Role of the adhesion molecule lymphocyte function associated antigen 1 in toxic shock syndrome toxin 1-induced tumor necrosis factor alpha and interleukin-1 beta secretion by human monocytes. We previously demonstrated that the induction by staphylococcal toxic shock syndrome toxin 1 (TSST-1) of tumor necrosis factor alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) secretion by human monocytes requires direct T cell-monocyte contact. In the present study, a role for the adhesion molecule lymphocyte function associated antigen 1 (LFA-1) in TSST-1-induced cytokine secretion by human monocytes among 12 normal healthy donors was investigated. Monoclonal antibodies to the alpha chain (anti-CD11a) and to the beta chain (anti-CD18) of LFA-1 significantly inhibited TSST-1-induced TNF-alpha and IL-1 beta secretion (P < 0.025; Wilcoxon signed-rank test, two tailed), while a control monoclonal antibody directed against the monocyte CD14 antigen had no effect. These results suggest that LFA-1 may play an important role in the secretion of TNF-alpha and IL-1 beta by TSST-1-stimulated human monocytes, likely by promoting cell-cell adhesion between monocytes and lymphocytes.


Effect of immunization with Freund's adjuvant and pneumolysin on histologic features of pneumococcal infection in the rat lung in vivo. Immunization with Freund's adjuvant and pneumolysin and stimulation with Freund's adjuvant alone both reduced the severity of the pneumonia caused by injections of bacteria into the apical lobe bronchi of rats. Neither protocol influenced the incidence of pneumococcal bacteremia. Illness sufficiently severe to require sacrifice was delayed from 2.8 days in nonimmunized animals to 5.7 days in those immunized with Freund's adjuvant and pneumolysin (P < 0.05) and 4.5 days in those stimulated with Freund's adjuvant alone (P, not significant).


Human neutrophil azurocidin synergizes with leukocyte elastase and cathepsin G in the killing of Capnocytophaga sputigena. Azurocidin was purified in the presence of phenylmethylsulfonyl fluoride. Electrophoresis revealed at least seven species which exhibited N-terminal sequences consistent with azurocidin. Azurocidin exhibited no bactericidal activity against Capnocytophaga sputigena or other oral bacteria but synergized the bactericidal activity of enzymatically active elastase. Azurocidin also interacted synergistically with cathepsin G.


Human factors in firefighting: ergonomic-, cardiopulmonary-, and psychogenic stress-related issues. There are many issues in firefighting that involve human factors and cardiopulmonary conditioning. Population-based mortality and disability surveillance studies suggest a relatively small but significant excess of disability but not mortality from nonmalignant cardiovascular disease for firefighters. More targeted cohort and case-control studies do not support such an excess and instead suggest a strong healthy worker effect. Pulmonary function among firefighters has been extensively studied, with contradictory findings. Extreme exposures and long-term exposure in combination with cigarette smoking may be risk factors for respiratory disorders and accelerated decline in airflow. It appears likely that individual firefighters who show early signs of illness are often selectively transferred out of active firefighting positions. Despite exposure to substances such as carbon monoxide that may predispose to cardiovascular mortality and morbidity, excesses are not consistently shown in mortality studies. Clinical studies of individual firefighters do suggest an elevated risk for myocardial ischemia. The ergonomic demands of firefighting are extreme at peak activity because of high energy costs for activities such as climbing aerial ladders, the positive heat balance from endogenous and absorbed environmental heat, and encumbrance by bulky but necessary protective equipment. The psychological stresses of firefighting include long periods of relative inactivity punctuated by highly stressful alarms and extremely stressful situations such as rescues, as reflected in physiological and biochemical indicators. Firefighters are at risk for depression and post-traumatic stress disorder, although morale overall is generally much higher than in comparable occupations. Women firefighter candidates as a group perform less well on selection test simulating the demands of active firefighting, but some individual women perform very well.


Exposure to soluble barium compounds: an interventional study in arc welders. Soluble barium (Ba) compounds are well-known toxicants. Intoxications are mainly known in an acute form from casual or suicidal oral ingestion. No scientifically based data are available on possible health effects of inhalative exposure to soluble Ba salts at the workplace. Therefore, we investigated 18 welders in an interventional study over 1 week. They performed welding of Ba-containing stick electrodes and self-shielded flux cored wires under conditions similar to real working conditions. The welding fumes contained 31%-37% Ba, more than 90% of which was soluble in acids. Without appropriate preventive measures, a high rate of measurements exceeded the TLV values for total welding fumes of 5 mg/m3 and for soluble Ba of 0.5 mg/m3. The median fume concentrations were 13.2 mg/m3 in stick electrode welding and 12.3 mg/m3 in flux cored wire welding. The median Ba concentrations were 4.4 and 2.0 mg/m3 respectively. An integrated exhaust system built into the gun proved to be efficient in flux cored wire welding. The internal exposure to Ba reached median urine levels up to 101.7 micrograms/l (normal: below 20 micrograms/l) and median plasma concentrations of up to 24.7 micrograms/l (normal: below 8 micrograms/l). No health impact on the welders could be proven, but hypokalemia may have occurred as a result of the Ba exposure.


Use of pharmaceuticals in industrial workers--possible implications for epidemiological studies. A total of 129 workers exposed to carbon disulphide (CS2) and 81 non-exposed controls were asked about their current use of pharmaceuticals, using a self-administered questionnaire. In all, 31% of the exposed and 19.8% of the non-exposed used some medicine (P = 0.08). The average number of pharmaceuticals per subject amounted to 0.71 in the exposed vs. 0.36 in the non-exposed (P = 0.049). Predominant types of medicines used were analgesics (12.4% in the exposed vs. 8.6% in the non-exposed, P = 0.50) and sedatives/hypnotics (10.1% in the exposed vs. 4.9% in the non-exposed, P = 0.21). The pharmaceuticals consumed can cause numerous (side) effects that are similar to the toxic effects of CS2. To take into account these possibly confounding agents, a classification system for possible (side) effects of pharmaceuticals was developed, taking the dose into account. According to this method, many (side) effects of pharmaceuticals that could occur were recorded with higher frequency and intensity in the exposed subjects. Potential (side) effects that occurred significantly more frequently in the exposed than in the non-exposed were: tiredness, sedation, dizziness (20.9% vs. 4.9%, P = 0.001), excitation, anxiety (10.9% vs. 2.5%, P = 0.03), vision disturbances (7.0% vs. 0%, P = 0.01), and erection decrease (5.4% vs. 0%, P = 0.045). The implications of these findings for epidemiological studies are discussed.


Changing cancer risk pattern among Finnish hairdressers. A cohort of 3637 female and 168 male hair-dressers in Finland was followed up for cancer through the Finnish Cancer Registry in 1970-1987. Compared with the total population, the women had a significantly elevated risk (standardized incidence ratio 1.7) during the first third of the observation period, but not thereafter. For the total follow-up period, the relative risks were highest for nonmelanoma skin cancer (2.0), lung cancer (1.7), ovarian cancer (1.6), cervical cancer (1.5), and cancer of the pancreas (1.5); only the risk of ovarian cancer was statistically significant. A decrease in relative risk with time was observed for many primary sites, e.g., pancreas, cervix uteri, central nervous system, and thyroid. The opposite was true for lung and skin: An increased risk was found only in 1982-1987. The excess was most prominent in the oldest age groups with the longest time span since the first employment as a hairdresser. Among men, too, the general cancer risk was highest (1.6) during the first third of the observation period. An excess of cancers of the lung and the pancreas was observed. The small numbers, however, did not allow any further conclusions. The changes in the cancer risk pattern over time may be associated with changes in working conditions in hairdressing salons.


Immunological findings and respiratory function in cotton textile workers. Immunological parameters were studied in a group of 24 cotton textile workers. These were volunteers from a cohort of 106 (83 women and 23 men) previously studied textile workers. A group of 30 employees from a bottle packing plant served as a control for the immunologic studies. The subgroup of volunteers undergoing immunologic testing did not differ from the original cohort of textile workers in age, sex, smoking history, or prevalence of most chronic respiratory symptoms, nor were there any significant differences in baseline lung function or across-shift changes. The 24 cotton worker volunteers underwent skin testing with extracts of cotton dust and cotton seed. Eight of these 24 (33.3%) had positive tests, and 5 of the 8 had elevated serum immunoglobulin E (IgE) levels. Only one of the 8 skin-test-positive workers had symptoms of byssinosis. Only 1 of 30 control workers' skin tested with cotton extract reacted, and none had an increased serum IgE level (P less than 0.01). Both baseline lung function and across-shift changes did not differ between workers with positive and negative skin test reactions or between workers with normal and elevated IgE levels. Additionally, we studied the response in vitro of nonsensitized guinea pig trachea to cotton bract extract and demonstrated a dose-dependent contractile response. These data suggest that while immunological findings are frequent in textile workers, they correlate poorly with respiratory symptoms and function and may not be the basis for the airway obstruction seen in this disease.


Investigations on health hazards of chimney sweeps in Germany: results of a follow-up study. Within the framework of a longitudinal study, 127 chimney sweeps from the area of Upper and Middle Franconia (Bavaria, Germany), who had participated in a first medical check-up in 1974, were offered follow-up examinations in 1990. Eighty-one subjects participated in these examinations; in addition individual occupational case histories and medical case histories were obtained for a further 15 and 35 chimney sweeps, respectively. Five test subjects had died before the evaluation deadline (August 15, 1990). The causes of death were a non-Hodgkin's lymphoma, a bladder carcinoma, pulmonary metastases with unknown primary tumour, a suicide and an acute myocardial infarction. Conspicuous results were carcinoma of the oesophagus in one case and leucoplakia of the mucous membranes in the mouth and pharyngeal region in three cases; furthermore one chimney sweep had two haemorrhagic lumps on his vocal cords. Taking into account important non-occupational hazards (alcohol and nicotine abuse) as possible causes of these changes and the lack of relevant occupational exposure to products of incineration over a number of years, none of these cases nor any of the other ascertained results could be considered likely to be causally related to occupational activities. Due to the small number of cases, an epidemiological risk evaluation did not seem useful. Comparison with the results of other chimney sweep studies published in the international literature is not helpful due to the differences in study design, the varying case frequencies, and the different conditions of exposure.


Assessment of thyroid, testes, kidney and autonomic nervous system function in lead-exposed workers. The objective of the study was to assess whether moderate occupational exposure to lead may be associated with early changes in potential target organs (thyroid, testes, kidney, autonomic nervous system). Workers exposed to lead in a lead acid battery factory (n = 98; mean blood lead 51 micrograms/dl, range 40-75 micrograms/dl) and 85 control workers were examined. None of the indicators of kidney function (in urine: retinol-binding protein, beta 2-microglobulin, albumin, N-acetyl-beta-D-glucosaminidase; in serum: creatinine, beta 2-microglobulin), endocrine function (follicle-stimulating hormone, luteinizing hormone, thyroid-stimulating hormone, thyroxine, triiodothyronine) and autonomic nervous system (R-R interval variations on the electrocardiogram) were correlated with lead exposure (blood lead or duration of exposure) or showed significantly different mean values between the exposed group and controls. These results and an assessment of the published data suggest that compliance with the Directive of the Council of the European Communities on lead exposure (health surveillance in workers whose lead in blood exceeds 40 micrograms/dl and removal from exposure when blood lead exceeds 70-80 micrograms/dl) would prevent the occurrence of significant biological changes in the majority of lead-exposed workers.


Occupational risk factors for congenital heart disease. To investigate possible associations between cardiovascular malformations and maternal occupational exposure to various factors during the first trimester of pregnancy, 406 cases and 756 controls were studied retrospectively. The cases were taken from all infants diagnosed with cardiovascular malformations born in Finland during 1982 and 1983. The controls were randomly selected from all normal births in the country during the same period. All mothers were interviewed approximately 3 months after delivery by a midwife, using a structured questionnaire. Maternal overall exposure to chemicals at work was more prevalent among the case group (35.8%) than the control group (26.2%, P less than 0.01). Among the specific chemical groups, maternal exposure to dyes, lacquers, or paints was significantly associated with the risk of congenital heart disease. Exposure to organic solvents during the first trimester seemed to increase to risk of ventricular septal defect (P less than 0.05). Work at video display terminals was slightly more prevalent among the case group (6.3%) than among the control group (5.0%). The mothers' education level, regular exposure to passive smoking at work, or temperature at the workplace were not risk factors for congenital heart disease in the offspring, neither was maternal exposure to microwave ovens, disinfectants, pesticides, or anesthetic gases. It is concluded that many maternal exposures at work seem not to have a teratogenic effect on the fetal heart, although the limited power of this investigation needs to be borne in mind.


Increase in sister chromatid exchange rates in association with occupational exposure to N,N-dimethylformamide. The effects of occupational exposure to N,N-dimethylformamide (DMF) on sister chromatid exchange (SCE) rates were studied in peripheral lymphocytes from 22 DMF-exposed women (aged 22-52 years) in comparison with 22 sex-, age-, and residence-matched controls. All subjects were nonsmokers and nondrinkers as confirmed by medical interview. The 22 pairs were divided by the intensity of exposure to DMF into 3 subgroups of high-exposed (8 pairs with mean DMF exposure at 5.8 ppm), middle-exposed (5 pairs with DMF at 0.7 ppm in combination with toluene at 0.9 ppm), and low-exposed (9 pairs with DMF at 0.3 ppm). The SCE rates were significantly higher in the high (P less than 0.005) and middle (P less than 0.01) exposed than in their matched pairs, and the increase was related to the intensity of DMF exposure.


Elevated urinary thioether excretion among bidi rollers exposed occupationally to processed tobacco. Manufacture of bidis - the Indian version of cigarettes - is one of the largest cottage industries in India. Bidi rollers handle 225-450 g of bidi tobacco per day and inhale tobacco dust and volatile components present in the work environment. Since tobacco is known to be mutagenic and carcinogenic, urinary cotinine was estimated in bidi rollers and control subjects as an index of tobacco-specific exposure while the concentration of urinary thioethers was determined to ascertain exposure to electrophilic moieties. Detection of cotinine in urine samples from bidi rollers with no tobacco habits indicated that occupational exposure leads to cutaneous absorption of tobacco constituents and the resultant increase in exposure to alkylating agents was evident from elevated urinary thioether levels.


Occupational exposure to antineoplastic agents at several departments in a hospital. Environmental contamination and excretion of cyclophosphamide and ifosfamide in urine of exposed workers. The occupational exposure to cyclophosphamide (CP), ifosfamide (IF), 5-fluorouracil (5FU), and methotrexate (MTX) of 25 pharmacy technicians and nurses from four departments of a hospital was investigated. Previously developed methods for the detection of exposure to some antineoplastic agents were validated. Exposure to CP, IF, 5FU, and MTX was measured by the analysis of these compounds in the environment (air samples and wipe samples from possible contaminated surfaces and objects). Contamination of the work environment was found not only on the working trays of the hoods and on the floors of the different rooms but also on other objects like tables, the sink unit, cleaned urinals and chamber pots, and drug vials and ampules used for preparation and packing of drugs. The gloves used during preparation of the drugs and during cleaning of the hoods were always contaminated. The uptake of CP or IF was determined by the analysis of both compounds in urine. CP or IF was detected in the urine of eight pharmacy technicians and nurses. The amounts ranged from less than 0.01 to 0.5 micrograms (median: 0.1 microgram). CP and IF were found not only in the urine of pharmacy technicians and nurses actively handling these compounds (n = 2) but also in the urine of pharmacy technicians and nurses not directly involved in the preparation and administration of these two drugs (n = 6). CP and IF were excreted during different periods ranging from 1.40 to 24.15h after the beginning of the working day, suggesting different times of exposure, different exposure routes, and/or interindividual differences in biotransformation and excretion rate for these compounds.(ABSTRACT TRUNCATED AT 250 WORDS)


Absence of blue-yellow color vision loss among workers exposed to toluene or tetrachloroethylene, mostly at levels below occupational exposure limits. Possible color vision loss was examined with Lanthony's new color test and Ishihara's color vision test in 261 solvent workers and 120 controls (48 men and 72 women). The solvent workers were exposed to either predominantly toluene [46 ppm as geometric mean (GM); 63 men and 111 women], tetrachloroethylene alone (13 ppm; 30 men and 34 women), or a mixture (14 men and 9 women) of tetrachloroethylene (12 ppm) and trichloroethylene (7 ppm). The only instances of color vision loss that were detected in either the exposed workers or the controls were six cases of red-green loss (all in men). These six cases of red-green loss showed an unbiased distribution between the exposed workers and the nonexposed controls.


Detection of carbon disulfide in breath and air: a possible new risk factor for coronary artery disease. Carbon disulfide (CS2) is toxic to the heart and arteries; chronic exposure can result in accelerated atherosclerosis and coronary artery disease in humans and animals. Exposure to CS2 was investigated in normal volunteers working in New York City, using a new and highly sensitive assay. Volatile organic compounds in breath and air were captured in adsorbent traps containing graphitized carbon and molecular sieve, then thermally desorbed, concentrated by two-stage cryofocusing, and assayed for CS2 by gas chromatography/mass spectroscopy. Breath CS2 assays were performed in 42 normal volunteers, as well as in room air and in outdoor air collected at sites in and around New York City. The assay was linear, reproducible, and sensitive to picomolar (10(-12) mol/l) quantities. CS2 was detected in all samples of breath and indoor and outdoor air (mean concentrations were 5.25 pmol/l, SD = 3.89 in breath, 8.26 pmol/l in indoor air, and 3.92 pmol/l in outdoor air) (NS). The alveolar CS2 gradient (alveolar-inspired CS2) ranged from -20.0 to 8.0 nmol/l, separating subjects into either "excreters" or "retainers" of CS2. In view of the known toxicity of CS2, atmospheric pollution with CS2 merits attention as a possible new risk factor for the development of accelerated atherosclerosis and coronary artery disease.


Shiftwork: its impact on the length and quality of sleep among nurses of the Valencian region in Spain. Previous research has shown the repercussions of shiftwork for workers' sleep. The objective of the present work is to evaluate the impact of shiftwork on the length and quality of sleep among nurses and on the intake of psychotropic drugs. A cross-sectional epidemiological study was carried out in 606 female nurses and 367 male nurses selected at random from the public hospitals in the Valencian region. Information was collected by means of a questionnaire. Univariate and multivariate statistical analysis techniques were used. For both female and male nurses, shiftwork led to a reduction in the length of sleep (by 2 h in those permanently on night shifts and by 30 min in those on a rotating night shift system) and an alteration in the quality of sleep (difficulty in sleeping, intermittent sleep, early waking, etc. occurred 10% more frequently), but it did not lead to an increase in the consumption of psychotropic drugs.


Aptitude for physical exercise in a population of female hospital workers. The aim of this study was to evaluate the level of physical capacity in a female hospital population of Paris and its suburbs. A total of 1505 women working in the selected departments filled in a questionnaire concerning their working conditions, life habits and health and also attended a medical examination. The effort test performed consisted in flexing the legs 20 times with the chest held straight, in 40 s. The heart rates were measured for the first, the second and the third minutes of recovery (first 15 s multiplied by 4). The blood pressure was measured just after the heart rate, for the first and the third minute. Recovery indices have been constituted from the results. The respective weights of anthropometric and sociodemographic risk factors for recovery indices were studied in multiple logistic regression models. The classification enables us to consider about 25%-30% of our population as having a satisfactory physical capacity, about 26%-27% as having an acceptable capacity, and about 24%-27% as having a weak capacity. About 21% of the population presented an excessive pressure reaction and 44% a questionable pressure reaction. Our results concerning the level of physical capacity of the female nursing staff should be taken into account especially in the future planning of work loads and architectural choices, which must avoid excessive physical burdens in relation to this level. An improvement in the level of physical capacity could be envisaged as well.


Clinical studies in workers engaged in maintenance of watermark moulds in a paper mill. Thirty subjects engaged in maintenance and repair of moulds used for producing watermarks on paper were studied, along with 27 control subjects from the same paper mill. The workers were simultaneously exposed to copper, chromium, zinc, xylol, and fumes of sulphuric acid in the course of their work. The study subjects were investigated for clinical, occupational, radiological haematological and psychological details. The aforementioned combined exposure was found to be responsible for a high prevalence of symptoms pertaining to the respiratory system and higher nervous functions. Breathlessness (26.7%), expectoration (10.0%) and emphysema (10.0%) were significantly higher among the exposed subjects. The exposed subjects also showed lowered visuomotor coordination and delayed reaction to light and sound stimuli.


Rheological and immunological findings in dockers with vibration-induced white fingers. The aim of the present study was to characterize rheological and immunological features involved in the pathogenesis of vibration-induced white fingers (VWF). Plasma viscosity, at two shear rates (580 s-1 and 1164 s-1), levels of immunoglobulins (IgG, IgM, IgA), circulating immune complexes, rheumatoid factor, antinuclear antibodies, fibronectin, fibrinogen, hemoglobin and erythrocyte sedimentation rate were analysed in 30 male dockers with VWF and in 30 healthy male referents unexposed for hand-arm vibrations. Decreased plasma viscosity was observed among the men with VWF, although formal significance (P less than 0.05) was only obtained at shear rate 580 s-1. The decrease was mainly seen among smokers. In the study there were no significant differences between the VWF group and the referents with regard to immunoglobulin levels, autoantibodies and other plasma proteins. From the study it is concluded that workers with VWF may have a decreased plasma viscosity. The biological relevance of this observation is uncertain and deserves further study.


Stereometabolism of ethylbenzene in man: gas chromatographic determination of urinary excreted mandelic acid enantiomers and phenylglyoxylic acid and their relation to the height of occupational exposure. Ethylbenzene is an important industrial solvent and a key substance in styrene production. Ethylbenzene metabolism leads to the formation of mandelic acid, which occurs in two enantiomeric forms, and phenylglyoxylic acid. To decide which enantiomer is preferably formed, 70 urine samples of exposed workers were taken at the end of shifts and--after 3-pentyl ester derivatisation--gas chromatographically analysed. The R/S ratio of mandelic acid enantiomers in urine amounts to 19:1, which means that R-mandelic acid is a major metabolite and S-mandelic acid is one of the minor urinary metabolites of ethylbenzene in man. The R/S ratio is independent of ambient air concentration of ethylbenzene within the investigated range. Compared to an ethylbenzene monoexposure the height of total mandelic acid excretion is decreased in the case of coexposure to other aromatic solvents.


Percutaneous absorption of N,N-dimethylformamide in humans. Skin penetration fo N,N-dimethylformamide (DMF) liquid or vapour was studied in volunteers. Exposure to liquid DMF was performed in two ways: in a "dipping experiment", one hand was dipped up to the wrist in DMF for 2-20 min, while in a "patch experiment", 2 mmol DMF was applied to the skin and allowed to be absorbed completely. The period of exposure to DMF vapour (50 mg.m-3) was 4 h. The DMF metabolites N-hydroxymethyl-N-methylformamide ("MF"), N-hydroxymethylformamide ("F"), and N-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC) were monitored in the urine. Liquid DMF was absorbed through the skin at a rate of 9.4 mg.cm-2.h-1. Percutaneous absorption of DMF vapour depended strongly on ambient temperature and humidity and accounted for 13%-36% of totally excreted "MF". The results suggest that skin absorption of liquid DMF is likely to contribute to occupational exposure substantially more than penetration of DMF vapour. The yield of metabolites after transdermal DMF absorption was only half of that seen after pulmonary absorption. Elimination of "MF" and "F" but not that of AMCC was delayed, which supports the contention that AMCC should be used instead of "MF" as the most suitable biomarker of DMF in cases where percutaneous intake can occur.


Absorption, metabolism and elimination of N,N-dimethylformamide in humans. Excretion of N,N-dimethylformamide (DMF) and DMF metabolites N-hydroxymethyl-N-methylformamide ("MF"), N-hydroxymethyl-formamide ("F") and N-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC) has been monitored in the urine of volunteers during and after their 8-h exposure to DMF vapour at a concentration of 10, 30 and 60 mg.m-3. The pulmonary ventilation in these experiments was typically about 10 l.min-1 and the retention in the respiratory tract was 90%. After exposure to 30mg DMF.m-3, the yield of compound determined in the urine represented 0.3% (DMF), 22.3% ("MF"), 13.2% ("F") and 13.4% (AMCC) of the dose absorbed via the respiratory tract. The excretion curves of the particular compounds attained their maximum 6-8h (DMF), 6-8h ("MF"), 8-14h ("F") and 24-34h (AMCC) after the start of the exposure. The half-times of excretion were approximately 2, 4, 7 and 23 h respectively. In contrast to slow elimination of AMCC after exposure to DMF, AMCC was eliminated rapidly after AMCC intake. This discrepancy could be explained by rate-limiting reversible protein binding of a reactive metabolic intermediate of DMF, possibly methylisocyanate.


Hand-arm vibration syndrome and its prevalence in the present status of private forestry enterprises in Japan. Currently there are no limitations on age of employment on private forestries in Japan. Hence, it was hypothesized that in these kind of enterprises, elderly chain saw operators, or those with long-term exposure, might be at higher risk of developing hand-arm vibration syndrome (HAVS). We consequently investigated the prevalence of HAVS in 447 chain saw workers on private forestries in Gifu Prefecture, Japan, with particular reference to age and exposure period. Of this population, 43 (9.6%) had signs and symptoms of vibration-induced white finger (VWF), and among these workers the severity of finger blanching was significantly correlated (P less than 0.01) with the exposure period. Classification of all subjects by exposure period showed that workers with greater than or equal to 30 years' exposure had higher prevalences of VWF (20.9%) and numbness of the hands (25.4%) compared to other groups. Significant differences (P less than 0.01) were found between the functional capacities of workers with VWF and those of control subjects. We concluded that (a) the elderly chain saw operators and those with longer exposure should be moved to other jobs with a lower or no risk of exposure to vibration, and (b) the results of screening tests, even without cold water immersion (which we did not employ, in order to protect workers' hands), could be helpful for the identification of workers with VWF.


Reference values for blood benzene in the occupationally unexposed general population. Blood benzene was determined by gas chromatography-mass spectrometry in 431 "normal" subjects, subdivided into 155 rural subjects and 276 urban subjects. Blood benzene (mean value 262 ng/l) was significantly lower in rural (200 ng/l) than in urban (296 ng/l) workers, as well as differing significantly between 293 non-smokers and 138 smokers (205 ng/l and 381 ng/l, respectively). Among non-smokers, values were significantly higher (307 ng/l) in 76 chemical workers. In the total study population, in 95% of cases blood benzene was less than 718 ng/l, the 95th percentile being 514 ng/l in non-smokers vs 901 ng/l in smokers and 576 ng/l in rural vs 822 ng/l in urban subjects. Within each population subgroup, the difference between non-smokers and smokers was statistically significant, except among office workers (non-smokers 234 ng/l, smokers 304 ng/l). Blood benzene (y) was directly proportional to the number of cigarettes smoked (x) (y = 201 + 12x; r = 0.44; n = 431), and inversely proportional to the interval between the last cigarette and the time at which the blood samples was taken (z) (log y = 6.167-0.0015z; r = -0.461; n = 135). The blood half-life of benzene was about 8h. The multiple correlation between blood benzene (Cb), number of cigarettes per day (x) and time since the last cigarette (z) is: Cb = 417 + 7.2x - 0.41z (n = 135; R = 0.20; P less than 0.00001).


Insect hemoglobins (Chi tI) of the diptera family Chironomidae are relevant environmental, occupational, and hobby-related allergens. Six hundred and forty-two persons with hobby-related (n = 205), occupational (n = 85), or environmental contact (n = 352) to the midge and larval allergen Chi tI were studied. Frequencies of IgE-mediated sensitization in these selected populations were 36.1%, 24.7%, and 9.6% respectively. Occupationally sensitized subjects who had been heavily exposed showed higher levels of antibodies, were more frequently diagnosed as having bronchial asthma and less frequently as having conjunctivitis, and had a significantly shorter latency period when compared to environmentally exposed people or aquarists. Our results are evidence for a higher risk of sensitization and of bronchial asthma in highly exposed subjects.


Decreased excretion of thioethers in urine of smokers after the use of beta-carotene. Epidemiologic studies have demonstrated an inverse relation between vitamin A intake and lung cancer rate. There is strong evidence that the provitamin A, beta-carotene, plays a more important role in the protective effect than vitamin A itself. The anticarcinogenic properties of beta-carotene have so far been attributed to its scavenger properties in deactivating or trapping reactive chemical species such as singlet oxygen and certain organic free radicals. Smoking results in increased excretion of detoxification products of electrophilic agents (mercapturic acids) in urine. Since reactive electrophilic intermediates are involved in carcinogenesis, we performed a double-blind, placebo-controlled intervention trial to investigate whether the intake of beta-carotene by smokers would affect urinary thioether excretion. Before the intervention the beta-carotene group (n = 62) and the placebo group (n = 61) had similar thioether excretion levels in urine (4.2 vs 4.3 mmolSH/mol creatinine). During the intervention (20 mg beta-carotene daily for 14 weeks) the placebo group showed a 12% increase, whereas the beta-carotene group showed a 5% decrease (P = 0.004). After the intervention the beta-carotene group had a 15% lower thioether excretion level than the placebo group (4.1 vs 4.7 mmolSH/mol creatinine; P = 0.0017). Our study shows that urinary thioether excretion varies considerably over time, and that smokers have a decreased excretion of thioethers in urine after the use of beta-carotene.(ABSTRACT TRUNCATED AT 250 WORDS)


Role of occupational exposure to airway irritants in the development of asthma. In order to study the role of occupational exposure in the etiology of asthma, 78 asthmatics and 56 nonasthmatics from the Finnish twin cohort were investigated by means of a postal questionnaire. Among those studied were 31 identical twin pairs discordant with regard to asthma (i.e., only one member of the pair had asthma). The questionnaire inquired into the diagnosis and status of the asthma, smoking habits, atopic background, smoking history of the parents, and history as regards pets, and requested a detailed description of occupational exposure to airway allergens and irritants. Classification into asthmatics and nonasthmatics was based on the information gathered with the questionnaire, supplemented by other information whenever possible. Estimation of exposure was based on the subject's own report, on the work descriptions, and on the general knowledge about the exposure levels associated with work tasks in question. Exposure to organic solvents was found only in the asthmatic members of the discordant pairs, and none of the nonasthmatic persons had been exposed to solvents. There were no statistically significant differences as regards exposure to other unspecific irritants. Combined exposure to organic allergens and airway irritants was more common in the asthmatics than in the nonasthmatics (P = 0.009). Exposure to irritants was also more common among the asthmatics than the nonasthmatics with similar exposure to organic allergens (P = 0.004).


Porcelain laminate veneers with three-dimensional shade reproduction. A new system for creating porcelain veneers with three-dimensional shade options is described. The development of a new porcelain consisting of an intense colour which provides natural tooth aesthetics in layers of only 0.5 mm has made the system possible. In addition a masking porcelain may be used over discoloured tooth tissue. The new system is claimed to supersede the sometimes less aesthetic shades created with other laminate systems, as well as enhancing the marginal integrity of the veneer.


Chromosome aberrations and micronuclei in lymphocytes of workers exposed to low and medium levels of styrene. In the present study we analysed 19 workers exposed to styrene in two factories where polyester resins were used. Because of the different sizes of the pieces undergoing resin processing, the environmental styrene concentrations and urinary mandelic acid (MA) levels of the analysed subjects were quite different in the two plants examined. Cytogenetic monitoring was performed by analysis of chromosome aberrations (CAs) and micronuclei (Mn) in peripheral blood lymphocytes. Cytogenetic analysis revealed a significant increase in the percentage of aberrant cells and total aberrations in the group with higher styrene exposure (group 2) and no increase in the group with lower exposure (group 1), as compared with matched controls. Mn frequencies were not significantly increased in the two exposed populations. No correlations between length of exposure and CA or Mn frequency were found, and a weak correlation was found between exposure levels, measured as urinary MA, and Mn frequencies. Only 5 of the 12 exposed workers examined in group 2 had urinary MA levels higher than the limit recommended by the ACGIH in 1990-91 [1]. Significant increases in DNA damage are therefore already found at urinary MA levels lower than the internationally suggested exposure limits.


Saliva and dental caries: diagnostic tests for normal dental practice. Salivary diagnostics is now entering the surgery of the modern dentist, although no test yet available is so specific and sensitive that caries can be diagnosed from saliva samples only. The present tests are useful for estimating the caries activity due to bad dietary habits (salivary lactobacilli), establishing the presence of infection (salivary mutans streptococci), and identification of salivary yeasts for the determination of the medical condition of the patient. Buffer capacity reveals the most important host response factor acting against caries, while measures of flow rate form the diagnostic basis for treatment planning. These tests, alone or in combination, are now so easy to perform that they should be used in every dental practice.


Is there a need for gerodontology?

Is there a need for gerodontology? One of the major criteria of successful ageing is maintaining a natural, healthy, functional dentition throughout life, including all the social and biological benefits such as aesthetics and comfort, and the ability to chew, taste and speak. However, the oral health of elderly people is far from optimal. The treatment needs are high due to edentulism, missing teeth, caries, periodontal diseases and tooth wear resulting in impaired oral functions. The demand for treatment is much lower than the need. In the future the elderly will retain their natural dentition and more teeth per individual will be present. Despite this there will be a rise in edentulousness due to the sharp rise in numbers of the elderly population. The 'new elderly' will be more critical and more demanding of oral health care services. The dental profession and governments in all industrialised countries must be aware of these trends which should be reflected in undergraduate and postgraduate education of dentists and in research. The European College of Gerodontology has been founded to contribute to solving all problems related to oral health and oral health care of the elderly.


A comparison of patients' perception of dental care offered by male or female dentists in New Zealand. Recent increases in women dentists in New Zealand follow similar trends in other Western countries. The career patterns of female dentists, and male dentists' attitudes towards women dentists in New Zealand have been previously studied. The aim of this study was to compare the attitudes and preferences of patients towards dental care offered by either male or female dentists, to determine what influences these preferences, and to discover whether or not these opinions differed between regular or irregular attenders.


The role of the dental team in promoting dental health and general health through oral health. The two major dental diseases are related to diet and dirt. These are common risk factors for a number of chronic diseases. A logical approach to the prevention of chronic diseases is to focus on risk factors rather than on specific diseases, a common risk factor approach using health promotion. Health promotion is the process of enabling individuals and communities to increase control over the determinants of health and thereby improve their health. The concepts incorporated in health promotion include a promotion of health through public policy, creating supportive environments, developing personal skills, strengthening community action and reorienting health services. The dental team should incorporate the following principles: integration with general health education, encouraging participation of the community, the public and staff in the planning process; making healthy choices the easier choices. By adopting a Common Risk Factor Strategy incorporated into Primary Health Care, dental teams can promote dental health and general health. The latter objective will be achieved by reducing pain and suffering related to dental diseases. A much broader remit for dental teams is outlined, one which will do justice to the abilities and training of all members of the team.


Disturbances caused by dental materials in magnetic resonance imaging. Nuclear Magnetic Resonance (NMR) is the latest addition to medical imaging technology. This technique plays an important role in head and neck diagnosis. Radiologists may encounter patients with fixed dental prostheses that may produce image distortion on MRI scans of the face. The MRI appearances of dental prosthetic materials was studied in vitro, including precious alloys, non-precious alloys, ceramic prostheses, dental amalgam and composite materials. It was found that non-precious alloys produce large image deformations, whereas precious alloys had no effect on MRI images. An in vivo study showed the anatomical zones that were most affected on MRI scans.


Racial differences in perception of oral health and oral health behaviours in Singapore. Knowledge of prevention can influence preventive dental behaviours. This study surveyed knowledge and preventive dental behaviours on the prevention of dental caries and gum disease among the adult population of the three major racial groups in Singapore. Respondents were asked to rate the importance of several preventive measures against dental caries and gum disease. Questions were also fielded on dental behaviours such as preventive visits to the dentist, toothbrushing and flossing. Results showed that there was a general lack of appreciation for the use of flossing, dental sealants and fluoride supplements. Although a majority of respondents thought that regular dental checkups would be essential for prevention, the proportion who actually saw the dentist for preventive care was significantly lower. Respondents provided inappropriate reasons for brushing their teeth. Differences in both preventive knowledge and preventive dental behaviours among racial groups were evident although these were attributed to differences in education and exposure to product information rather than to racial or cultural factors.


Disinfection and sterilisation: the duties and responsibilities of dentists and dental hygienists. Disinfection and sterilisation have received a considerable amount of attention due to the spread of AIDS in the past few years. There appears to be a low risk of occupational transmission of HIV, but this is not the case with other transmissible diseases. There are about 40 infection hazards for the patient and dental personnel in the dental surgery. Disinfection and cleaning are important in disease containment and cross-infection control, and all members of the dental team must bear responsibility for this. Disinfection of hands, surfaces, instruments, impression materials, radiographic units and suction systems are discussed. In addition, sterilisation and hygiene management of the reception area are considered. The duties and responsibilities of the dental team are emphasised.


Rinses for the control of dental caries. Fluoride mouthrinsing at two different strengths and two different rinse frequencies has proven a versatile method of caries control for individual home-based programmes and community school-based programmes. An advantage of mouthrinsing is that the vehicle is not complex and does not interfere with the intraoral distribution of fluoride ions to caries predilection sites. An average caries reduction of about 30 per cent can be expected from use of this method. The percentage caries reduction, which is a relative figure, is considered to be a property that is intrinsic to the preventive regimen itself, in this case fluoride mouthrinsing, and is unaffected by the caries attack rate of the population being served. On the other hand, the benefit of the procedure is a function of the numerical caries reduction achieved by the intervention. Numerical reductions are absolute figures which do depend upon the caries rate of the population. High caries attack rates increase the numerical caries reduction because there are more lesions to inhibit; low attack rates produce low numerical reductions and consequently low benefits. Therefore, the decision to use fluoride mouthrinsing for either an individual or a community must be based upon knowledge of the caries risk of the targeted individual or group.


Rinses to control plaque and gingivitis. The dental profession and the public have two different perceptions when it comes to oral hygiene. The profession has oral health as its main objective whereas the public is more concerned with personal cleanliness and social acceptability. Nevertheless the desired outcome is the same, namely to remove supragingival plaque. The concept of using a mouthrinse as an adjunct to brushing with a dentifrice is a sound one. In recent years there has been a rapid increase in the use of mouthrinses and this review considers the relative merits of those currently on the market. It is evident that some progress has been made in satisfying the priorities of the consumer and clinician.


Subgingival irrigation systems for the control of oral infections. The use of subgingival irrigation systems for the control of oral infections is an attractive possibility. The main advantage would seem to be that it would provide a means of delivering therapeutic agents to sites otherwise inaccessible to the effects of mouthrinses. Much research has therefore concentrated on the methods of delivery and the agents so delivered. The effects of various trials on individuals with good and poor oral hygiene and using a variety of different agents is reviewed.


Microbiological evaluation of the efficacy of chlorhexidine in a sustained-release device for dentine sterilization. The aim of this in-vitro study was to evaluate the effect of chlorhexidine in solution and in a sustained-release device as an intracanal medication. Hollow cylindrical dentine specimens prepared from bovine incisors were incubated with Streptococcus faecalis for a period of 3 weeks. The intracanal medicaments tested were 0.2% chlorhexidine gluconate solution (CH), chlorhexidine in a sustained-release device (1.2 mg) (SBD), camphorated paramonochlorophenol (CMCP), and a control (no medication). Each medicament was introduced into the lumen of one dentine specimen and incubated for 5 min, 24 h, 48 h or 7 days at 37 degrees C. The bacteriological samples were taken by shaving the dentine inside the lumen with dental burs ranging in size from ISO 023-033. The dentine powder was collected in test-tubes containing growth medium and incubated for 24 h. The optical density of the medium was recorded by means of a spectrophotometer at a wavelength of 540 nm. There was a statistically significant difference between the control group and all the medicaments tested.


Bacterial invasion of non-exposed dental pulp. Anaerobic procedures were adopted to demonstrate the early bacterial invasion of non-exposed dental pulps, and to isolate and identify the bacteria. Of 19 freshly extracted teeth which originally exhibited deep dentinal lesions, clinical examination and electric pulp testing showed that nine of them had no pulpal exposure. Thus the pulps of these teeth were covered by clinically sound dentine beneath the carious lesion. Bacteria were found to have invaded the pulps of six of these nine teeth. The predominant bacteria were obligate anaerobes belonging to the genera Eubacterium, Propionibacterium and Actinomyces. Other obligate anaerobes were Lactobacillus, Peptostreptococcus, Veillonella and Streptococcus. The bacterial composition resembled that of the deep layers of dentinal lesions described previously, suggesting that the bacteria isolated in this study had passed through some individual dentinal tubules, to invade the dental pulp.


Efficacy of a sustained-release device containing chlorhexidine and Ca(OH)2 in preventing secondary infection of dentinal tubules. This study was conducted to evaluate the efficacy of the antibacterial activity of Ca(OH)2 and a sustained-release device containing chlorhexidine (SRD) in both sterilization and prevention of secondary infection of the root canal system. Bovine root dentine specimens previously incubated with Streptococcus faecalis were used in this experiment. Two different formulations of the SRD (differing in their cross-linkage), Ca(OH)2 and normal saline (control) were evaluated. The degree of bacterial infection of the root canal was tested after incubation periods of 24 h, 72 h and 7 days with these medicaments. Their efficacy in preventing secondary infection after recontamination was tested after 72 h and 7 days. The results demonstrated that both formulations of the SRD significantly reduced the bacterial population in the primary infected groups, as well as preventing secondary infection of the dentinal tubules in the recontaminated group. By contrast, Ca(OH)2 did not show any antibacterial activity, and failed to sterilize the dentinal tubules or prevent secondary infection after recontamination at the time periods examined.


A survey of endodontic procedures performed by practitioners in limited practice. Patients are sometimes referred for treatment to dentists who limit their practices to endodontics. A survey of consecutive referrals to seven such dentists was undertaken. The most common reasons for such referrals were (i) for the retreatment of a tooth with a previous root filling, (ii) because the referring dentist was unable to control pain and/or swelling, or (iii) because the referring dentist was unable to diagnose the endodontic problem. Only 60 (12.8%) of the 469 reasons reviewed were in teeth that were symptomless, uncomplicated and untouched by the referring dentist.


Dentine-removing characteristics of K-files energized by the Piezon-Endo. This in-vitro study evaluated the pattern of dentine removal when a size 25 K-file energized by the Piezon-Endo was applied to flat surfaces of dentine under standardized conditions. The effects of power setting, interfacial force between file and dentine, direction of file oscillation and operator-assisted movement were examined. Vinyl polysiloxane impressions of the instrumented surfaces revealed characteristic patterns consisting of a series of oblique crests, similar to those observed in a previous study using the Cavi-Endo. Each crest was parallel to the next and separated by a relatively constant distance. These crests were disposed along the line of contact with the file. The Reflex microscope was used to determine the height, width and separation of these crests. There were differences in the amount and pattern of dentine removal compared with the study on the Cavi-Endo. When the file was held against the dentine surface using the minimum power setting and an interfacial force of 30 g, the pattern of dentine removal was very similar to that produced by the Cavi-Endo. Increasing the power setting to the maximum recommended for endodontics produced a slight but statistically non-significant increase in dentine removal. Further increase of the power setting to the absolute maximum produced significantly deeper and wider areas of dentine removal by the apical part of the file.(ABSTRACT TRUNCATED AT 250 WORDS)


Diagnostic dilemma: an unusual presentation of an infected nasopalatine duct cyst. The pertinent literature on nasopalatine duct cysts is reviewed. A case is reported in which a nasopalatine duct cyst infected by Actinomyces presented clinically with unusual features. The clinical findings could have been confused with an early acute periapical abscess arising from an incisor tooth. The relevant aspects of diagnosis are discussed.


Comparison of six files to prepare simulated root canals. 1. A total of 300 simulated root canals of various angles and positions of curvature in clear resin blocks were prepared by hand using either K-files, K-Flex files, Flexofiles, Flex-R files, Hedstrom files or Unifiles. Each file type was used to prepare 50 canals employing a linear filing motion and an anticurvature stepback technique. Part 1 of this two-part report describes the efficacy of the files in terms of preparation time, instrument failure, loss of canal length and weight loss from the blocks. Two-way analysis of variance confirmed that there was significant variation for each parameter between instruments, between canal types, and with interaction between instruments and canal types. Overall, preparation with Hedstrom files was significantly quicker than with any other file, whilst preparation with K-files and K-Flex files took significantly longer. Fracture and deformation of instruments occurred substantially less often with Flex-R and Hedstrom files, but significantly more often with Unifiles. Loss of working distance occurred with all file types, but was significantly greater in canals prepared with K-files. Unifiles and Hedstrom files were responsible for significantly more weight loss than the other files, whilst K-files produced significantly less weight loss. Canals with rough undulating walls were created most often by Hedstrom files and Unifiles. Overall, under the conditions of this study, Flexofiles, Flex-R files and Hedstrom files appeared to be substantially more effective than K-files, K-Flex files and Unifiles.


Comparison of six files to prepare simulated root canals. 2. A total of 300 simulated root canals of various angles and positions of curvature in clear resin blocks were prepared by hand using either K-files, K-Flex files, Flexofiles, Flex-R files, Hedstrom files or Unifiles. Each file type was used to prepare 50 canals employing a linear filing motion and an anticurvature stepback technique. Part 2 of this two-part report describes the efficacy of the files in terms of the prevalence of canal aberrations, the amount and direction of canal transportation and the overall postoperative canal shape. Hourglass shaped canals were found in 4.5% of curved canals, the majority of these being created by K-files and K-Flex files. Perforations were seen in 6.3% of curved canals, the majority being produced by Flex-R files and K-files. Excessive removal of material from along the inner aspect of the canal curve occurred in 10.4% of canals, by far the majority being created by Hedstrom files. Transportation of canals was a consistent finding with all instruments. Two-way analysis of variance revealed how significant differences in the absolute magnitude of transportation occurred between instruments, between canal types and by an interaction between instrument and canal type. In general, transportation was towards the outer aspect of the canal curve at the end-point of preparation and the zip and elbow, but towards the inner aspect at the beginning of the curve. Further towards the orifice, transportation reverted to the outer aspect of the canal curve.(ABSTRACT TRUNCATED AT 250 WORDS)


Blood flow changes in the dental pulp during limited exercise measured by laser Doppler flowmetry. The effect of limited exercise on pulpal blood flow was assessed by laser Doppler flowmetry (LDF). The primary aim of the investigation was to determine whether clinically significant changes could be induced by mild exercise when LDF was used to monitor pulpal blood flow. Blood flow readings were obtained from the coronal pulps of 17 upper central incisor teeth of 10 human volunteers before, during and after limited exercise. Readings were also obtained from the adjacent attached gingivae. Pulse rate was recorded concurrently. Pulpal blood flow was found to vary during exercise, with a mean percentage change of 38% from the level at rest; the range was from a 100% decrease to a 200% increase. The mean percentage increase in gingival blood flow was 65%, with a range of 6-300%. The main indication that blood flow was being assessed was the pulsatile nature of the output. Results were compared only within individual teeth. The pulse rate increased during exercise (mean percentage increase 54%, range 11-98%). There was no direct relationship between increased pulse rate and pulpal blood flow. It was evident that the mechanisms controlling pulpal and gingival blood flows differed. Laser Doppler flowmetry readings were only reproducible in individual teeth provided that the patient was at rest, and this should be taken into account in clinical or research measurements.


Variables affecting electronic root canal measurement. This study was conducted in two parts. In the first part, 20 single-rooted teeth that had been scheduled for extraction were investigated. The electronic root canal lengths were measured in vivo with a Dental Sono-Explorer type Y-III, and the actual canal lengths were measured after extraction of the teeth. The rate of agreement of the two measurements was 77.5% within a range of +/- 0.5 mm, while it was 100% at +/- 2.0 mm, which is acceptable clinically. In the second part, there were 19 simulated canals whose lengths and apical foramen sizes were known beforehand. Experiments revealed a negative correlation between the areas of the apical foramina and the difference between the electronic and the actual root canal lengths. This relationship was shown by the linear regression equation: ŷ = 0.6-1.6x. With the exception of the smallest areas of foramina, electronic root canal length measurements were less than the actual lengths.


A method for experimental dental radiography. An apparatus was designed for experimental dental radiography, which permitted separate adjustment of the subject, target and film. The precision of the apparatus was tested by radiographing a test subject, consisting of small steel globes embedded in a plastic plate. The subject was placed in the apparatus and exposed 30 times on dental X-ray film with different adjustments of angles and distances. All exposures were repeated after readjustment of the same form. Three linear distances between pairs of the projected steel globes were selected and measured on each radiograph. Depending on the different orientations of film, target and subject, the distances measured ranged from 9.0-11.1 mm, from 7.0-10.7 mm and from 12.7-17.3 mm, respectively. From the measurements on the radiographs the error of method was calculated to be 0.07-0.08 mm and the error of measurement to be 0.05-0.06 mm. The precision of the apparatus was thus found to be adequate for measurement of differences in small, but clinically relevant, distances.


The role of intracanal medication in root canal treatment. The role of intracanal medication as a root canal dressing is re-examined. In pulpectomy and some root canal treatments, where the root canal contains vital pulp tissue, it is doubtful whether a routine intracanal medicament is needed. In infected root canals, intracanal medication has been advocated for many purposes. An intracanal medicament is used to: (i) eliminate any remaining bacteria after canal instrumentation; (ii) reduce inflammation of periapical tissues and pulp remnants; (iii) render canal contents inert and neutralize tissue debris; (iv) act as a barrier against leakage from the temporary filling; (v) help to dry persistently wet canals. However, most of the indications for intracanal medicaments are questionable. Intracanal medicaments should only be used for root canal disinfection as part of controlled asepsis in infected root canals, and their role is secondary to cleaning and shaping of the root canal. Thorough canal debridement and adequate canal preparation are more pertinent, and their importance is emphasized. Bacteriological sampling may be necessary if a tooth does not respond to treatment, to help in the choice of intracanal medicament.


Failure characteristics of endodontically treated premolars restored with a post and direct restorative material. Ninety-one extracted maxillary premolar teeth were restored with a prefabricated post and amalgam, composite resin or glass-cermet core. Each group was again divided into three groups of 9-13 teeth to be subjected to an increasing load in one of three standardized directions (10, 45 and 90 degrees to the long axis of the tooth). Failure load and characteristics of failure were recorded. The glass-cermet-restored teeth had a lower strength than the other groups for every load direction (Student's t-test: P less than 0.01). Amalgam and composite resin groups showed a significant difference only for the 10 degrees loading condition (Student's t-test: P less than 0.02). Teeth restored with amalgam cores displayed a higher mean failure load, in combination with a 46% occurrence of root fracture.


The physical properties of a new sealing cement. This study was performed on a newly developed sealing cement, TS60, to evaluate its physical properties, namely sealing, setting time, compressive strength, solubility and ease of removal. It was compared with Temporary Stopping (GC Dental Industrial Corp., Tokyo, Japan), Eugedain (zinc oxide-eugenol based material, Showa Yakuhin Kako Co. Ltd, Tokyo, Japan) and Cavit-G (calcium sulphate based material, Espe Gmbh, Seefeld, Germany), which are typical commercially available sealing cements. The results of the study revealed that TS60 had excellent sealing properties, good compressive strength, low solubility, and was readily removable by heating and melting.


Pulp responses to two strains of bacteria isolated from human carious dentine (L. plantarum) (NCTC 1406) and S. mutans (NCTC 10919). A series of studies has been conducted in which monoinfected gnotobiotic rats were used to study the responses of the dental pulp to micro-organisms isolated from carious lesions in dentine. In this study pulp responses to L. plantarum (formerly odontolyticus) (NCTC 1406) in pure culture and in combination with S. mutans (NCTC 10919) are reported. The incidence of inflammation/necrosis/dentine bridge formation observed in animals monoinfected with L. plantarum was similar to that reported in previous germ-free studies. There was a greater incidence of dentine bridge formation in rats monoinfected with L. plantarum compared with those monoinfected with S. mutans. When the two organisms were combined, periapical inflammation was observed in 14% of the teeth examined after 28 days, but there was no significant difference in the incidence of dentine bridge formation. Considerable variation in the density of staining of the two microorganisms in histological sections was observed.


Pulp response to, and cariogenicity of, a further strain of Streptococcus mutans (NCTC 10832). The pulpal response to and cariogenicity of a third strain of Streptococcus mutans, namely S. mutans (NCTC 10832), was studied in monoinfected gnotobiotic rats of the Fischer strain using the techniques described previously by the present authors. Unlike S. mutans (NCTC 10449 and 10919), S. mutans (NCTC 10832) was associated with the presence of inflammatory cell infiltrates in the coronal pulp of a small number of teeth and extensive periapical inflammation 28 days after the creation of untreated pulpal exposures. S. mutans (NCTC 10832) was associated with the presence of extensive pulpal necrosis and reduced dentine bridge formation. These changes were similar to those noted with the other two strains of S. mutans. S. mutans (NCTC 10832) was non-cariogenic in monoinfected gnotobiotic rats of the Fischer strain.


Root fractures in permanent teeth: a clinical review. A retrospective study of 22 root fractures in 21 patients was performed. Ten patients were less than 11 years of age, and boys were involved more often than girls. Ten patients had more than one injured tooth, but there was no case of alveolar fracture. Twenty-one of the teeth were upper central incisors. Only 11 teeth were seen within the first week, so that not all teeth were splinted and not all displaced teeth were repositioned. Long-term clinical and radiographic review showed that loss of vitality of the coronal pulp could not be reliably detected for at least 1 year. No tooth became abscessed or developed a sinus tract, and resorption of bone at the fracture line was observed in only one out of five non-vital teeth. Lack of displacement and placing of a splint increased the chances of the pulp remaining vital and healing of the fracture occurring with hard tissue. Sclerosis of the coronal pulp occurred mainly when healing was by connective tissue. The apical pulp always remained vital, and there was sclerosis of the apical pulp in almost every case.


Asymmetry of the root canal foramen.

Asymmetry of the root canal foramen. Deviation of the major apical foramen from the anatomical root apex is a recognized phenomenon. To determine the frequency, position and mean distance of the major apical foramen from the anatomical root apex, 230 roots of permanent teeth were examined stereomicroscopically and radiographically. Radiographic analysis was used to establish how accurate the conventional radiograph was in displaying such a deviation. The frequency of deviation of the major foramen, determined stereomicroscopically, was 76%, and depended on the type of teeth examined. Radiographic analysis of the same sample revealed 57% of root canals had asymmetry of the root canal foramen. Agreement of stereomicroscopic and radiographic findings was found to be 61%. The most frequent deviation of the major foramen was on the distal root surface (29%), but this was not statistically significant. The mean distance between the deviation of the major foramen and the anatomical root apex was 0.99 mm. The study indicates that the clinician should consider deviation of the foramen during root canal treatment, as the deviation could not easily be detected radiographically.


Garré's osteomyelitis: a case report.

Garré's osteomyelitis: a case report. This is a case report of Garré's osteomyelitis caused by infection from a lower left molar which was successfully managed by root treatment following several unsuccessful attempts with antibiotic therapy alone. After 18 months there was complete resolution of the bony lesion.


Quantitative radioactive analysis of microleakage of four different retrograde fillings. Sealing properties of four different retrograde filling materials were investigated in vitro. Radioactive isotopes were applied in the root canal, and leakage into an extraradicular fluid was measured at regular intervals. The method permitted repeated observation of the specimens over prolonged periods of time. Forty single-rooted human teeth were biomechanically instrumented and obturated using calcium-hydroxide paste. Following obturation, an apicectomy was performed and retrograde cavities were filled with four different materials: group 1, non gamma 2 amalgam (Amalcap); group 2, glass ionomer cement (Ketac Silver); group 3, calcium-hydroxide-based root canal sealer (Sealapex); group 4, composite resin (Palfique Light-S). After removal of the calcium hydroxide, the teeth were immersed in a fluid. An isotope solution was then placed in the root canals. Samples were taken from the fluid at 0, 3, 7, 28, 56, 105, 210, 285 and 376 days to determine the radioactivity. It was found that Sealapex and Palfique Light-S showed significantly less leakage than amalgam and glass ionomer cement, which had the highest apical leakage.


Systemic release of corticosteroids following intra-dental use. Concern has been expressed in the past that the use of corticosteroids within root canal medicaments or pulp capping agents may lead to deleterious systemic effects. Calculations of the highest possible amounts that could be used, plus an analysis of the release and diffusion characteristics, and comparisons with known endogenous levels of corticosteroids, reveal that the intradental use of Ledermix paste and Ledermix cement is unlikely to result in any systemic side-effects.


Tissue responses to Hydron, assessed by intraosseous implantation. Teflon tubes containing freshly mixed, polymerized Hydron root canal filling material, fully set AH26 or Teflon were implanted into the mandible of guinea pigs and assessed histologically at 2 days, 1, 2, 4, 12 and 26 weeks. None of the materials tested elicited signs of overt or significant tissue damage, and polymerized Hydron was assessed to be as biocompatible as fully set AH26 and Teflon. Bone formed in very close apposition to the polymerized Hydron, whereas a soft tissue capsule separated the regenerated bone from implants of AH26 and Teflon.


Tissue responses to Hydron, assessed by intramuscular implantation. Freshly mixed polymerized Hydron root canal filling material, fully set AH26 and Teflon were implanted in the quadriceps muscle of guinea pigs and assessed histologically at 2 days, 1, 2, 3, 12 and 26 weeks after implantation. All materials were characterized by peri-implant fibrous connective tissue capsule formation. Von Kossa-positive calcific material was observed at the implant-tissue interface of Hydron implants. The amount of apparently calcified material increased with time. Inflammation was not a prominent tissue response for any of the test materials, nor was a foreign body giant cell response.


Cell responses to Hydron by a new in-vitro method. An in-vitro biotoxicity test system, suitable for the assessment of endodontic filling materials, has been developed and used to test cell responses to Hydron, AH26 and Tubliseal. A robust, well-characterized and stable cell line (L-cells) which was grown as uniform cultures on Millipore filters, has been used as indicator cells. As they approached confluence they were exposed to test substances for 24 h and biosynthetic activities were measured. The test system is a modification of that described by Wennberg et al. (1979). By inverting the cultures on organ-culture rafts, cells were separated from the test material, which was placed on top of the Millipore filters. Freshly mixed polymerizing Hydron and prepolymerized Hydron were tested. The cell responses were compared with those of cultures exposed to freshly mixed AH26 and Tubliseal. Polymerizing and prepolymerized Hydron depressed both cell division, assessed by 3H-thymidine incorporation, and the synthesis and secretion of matrix material as measured by precipitable 35S-sulphate. Prepolymerized Hydron decreased cell functions by 59% and 56% of live cell controls, respectively, while the freshly mixed polymerizing Hydron inhibited biosynthesis by 89% and 94%, respectively. The data for polymerizing Hydron were compared with results for other root-filling materials and showed similar values to those for Tubliseal (92% and 95%), but greater inhibition of biosynthesis than for AH26 (53% and 50%). The AH26 values were similar to those obtained from cultures exposed to the prepolymerized Hydron. Recovery of biosynthetic capacity by these cultures after removal of all endodontic material was also assessed. Partial biosynthetic recovery of cell cultures was observed 24 h after removal of preopolymerized Hydron.(ABSTRACT TRUNCATED AT 250 WORDS)


A five-year study of Hydron root canal fillings. A prospective clinical and radiographic study was conducted in order to compare Hydron and laterally condensed gutta-percha/AH-26 root canal fillings. Paralleling technique periapical radiographs were taken preoperatively, postoperatively and at recall appointments at post-treatment intervals of 6 months, 1 year, 2 years, 3 years and 5 years. Clinical examination at the recall appointments revealed no adverse signs or symptoms amongst all the patients who attended (mean attendance 44.5% at each interval). Radiographs were scored according to the periapical status of the treated root, and comparable bone healing rates were observed between the two root-filling materials. Among the patients attending recall appointments, there were no radiographic signs of failure of any of the 39 gutta-percha/AH-26 root canal fillings. However, three of the 35 canals filled with Hydron were classified as failures, and four required further assessment after the 5-year recall appointment. This study indicated that Hydron and gutta-percha/AH-26 root canal fillings were well accepted but, on the basis of radiographic assessment, success with gutta-percha/AH-26 was more predictable.


Assessments of social support exchanges: cognitions of the old-old. In this study of the old-old, perceptions of thirty-one individuals regarding exchanges in their social relationships are explored. Two questions are addressed: 1) What cognitive mechanisms are used to assess equity in social exchanges? 2) What is the relationship between these mechanisms and other psychological phenomena? Using a qualitative methodology, six cognitive mechanisms are identified. Their use appears to be associated with both beneficial and detrimental subjective reactions. Findings from this study suggest that cognitive mechanisms are an important focus of inquiry because they may mediate the relationship between social exchanges and well-being.


Employment, social networks, and health in the retirement years. The impact of employment on the health of retirees is examined, with particular attention to the hypothesis that social roles affect health through their impact on social networks. Data are based on comprehensive assessment questionnaires completed by 175 participants of a corporate sponsored geriatric clinic. Results indicate that employment in the retirement years is related to larger social networks and indirectly, through this relationship, to better perceived health. Of the three social network factors identified through factor analysis: family, friends, and confidant relationships, employment was significantly related only to the friendship component. A summary analytic model is presented and implication for interventions are discussed.


Quality in grandparent/grandchild relationships. Five elements identified from the literature as expressive of quality in grandparent/grandchild relationships were used in this study. Three hundred ninety-one young adults at a midwest university responded to questions concerning the quality of their relationships with their "most close" grandparent. Responses of the students validated the following five elements of quality as being associated with successful grandparent/grandchild relationships: 1) a fairly high degree of closeness, 2) a strong sense of being known by the grandparent, 3) a strong sense of the young adult's knowing the grandparent, 4) a sense of the grandparent being a fairly strong influence in the life of the grandchild, 5) a sense of an authentic or independent grandparent/grandchild relationship not dominated by, but supported by, the middle generation. Analysis of variance identified the impact of seven independent variables on the quality of grandparent/grandchild relationships.


The impact of stressful life events and social support on drinking among older adults: a general population survey. This article is an analysis of stressful life events, the buffering hypothesis, and alcohol use in a national sample of 1,418 respondents 60 years of age and over. The results indicate that older adults who experience stressful losses are significantly more likely to drink excessively than those who have not experienced such losses or who have experienced them to a lesser extent. Increased drinking among older adults may therefore be a reaction to life circumstances in which alcohol represents an attempt to cope with traumatic loss, personal as well as within the kinship network. Supportive resources of spouse, family, friends, and church appear to have a stress-buffering effects that reduces the excessive-drinking response to life crisis. Data suggest, however, that older persons are vulnerable to the magnitude of losses experienced as they grow older and lose more of their family, friends, and peers. These stressors appear to seriously impact their drinking behavior and are not effectively buffered. Respondents report that drinking may increase during periods of prolonged exposure to emotionally depleting life change and loss, when supportive needs may exceed the capacities of personal and social support resources.


African-American, Anglo-American, and Anglo-Canadian grade 4 children's concepts of old people and of extended family. A cross-national study of 104 fourth grade children's concepts of old people and extended family was conducted in Canada and the United States, using the Children's Attitudes Toward the Elderly Scale (CATE), and a modified version of the Gilby and Pederson (1982) Family Concept Interview. Both Anglo-American and African-American children were included in the U.S. sample. Results indicated that Anglo-American and Anglo-Canadian children were significantly more similar in their attitudes toward the elderly and their concepts of family than African-American and Anglo-American children. In comparison with the other two cultural groups, Anglo-American children were significantly more likely to include extended family members in their concept of who is family; Anglo-Canadian children had a significantly higher level of age discrimination ability; and African-American children showed a trend toward more positive attitudes toward older people. Overall findings of negative attitudes toward old people were consistent with earlier studies. The implications of children's ageist attitudes for increasingly aging Western societies are noted, particularly given impoverished children's potential need for extrafamilial social supports.


Service utilization by well-organized frail elderly individuals. In spite of extensive legislation intended to provide social services for elderly individuals, there is a lingering question about how much elderly persons actually use these services. This article reports findings from a study involving an innovative program called STAES (System to Assure Elderly Services), located in downtown St. Louis, Missouri and in particular finds that frail elderly individuals in the STAES program are using services in greater numbers than the review of the literature seems to suggest. In-home services such as homemaker services and visiting nurses' services are indeed used by elderly individuals who are in greater need than others. Through discussing the objective and operation of this program, the article explains why elderly individuals participating in the STAES program are effective users of publicly provided social services.


Development of an interview-based geriatric depression rating scale. The geriatric depression rating scale (GDRS) is a new interview-based depression rating scale designed for use with adults 60 years of age or older. The scale was developed to fill a need for an instrument that would be sensitive to the problems encountered in assessing depression among older adults. The GDRS was designed by using items from the self-report Geriatric Depression Scale (GDS) as topic areas in a structured clinical interview similar to that of the Hamilton Rating Scale for Depression (HRSD). The 35-item rating scale was administered to 68 older individuals with a range of affective disturbance. The scale was found to have internal consistency and split-half reliability comparable to the HRSD and GDS. Concurrent validity, construct validity, external criterion validity, sensitivity, and specificity were all found to be acceptable.


Socio-cognitive skills as a determinant of life satisfaction in aged persons. The purpose of this study was to explore the viability of a revised model of elderly life satisfaction, specifically evaluating the contribution of socio-cognitive skills. The role of such skills in relation to life satisfaction among aged persons has not been explored in research to date. Pilot data gathered from 60 community-living aged individuals indicated that numerous variables (e.g., subjective/objective health, education, financial satisfaction, role participation, subjective integration) significantly correlated with life satisfaction. However, the combined effects of two variables, persons' feelings of loneliness and isolation from their families and a measure of socio-cognitive skill, accounted for 49 percent of the variability in elderly life satisfaction. The effects of each on life satisfaction were unique however. Implications of these data and possible interventions for increasing elderly persons' life satisfaction are discussed.


A comparison of office and adult day care center older volunteers: social-psychological and demographic differences. Numerous researchers have compared older adults who volunteer with those who do not volunteer on several demographic variables. In contrast, in the present study we compared older adults (minimum age = 55 years old) who volunteered to work for a community organization at an office or in a day care center on social-psychological and demographic predictors. It was hypothesized that day care center volunteers would have higher scores than office volunteers on sympathy, role taking, and self-based salience of volunteer role (i.e., personal identity). In addition, office volunteers were expected to have higher scores than day care center volunteers on other-based salience of volunteer role (i.e., social identity). Discriminant function analysis indicated that day care center volunteers were higher than office volunteers on sympathy whereas office volunteers were higher than day care center volunteers on educational attainment, involvement in clubs and organizations, and role taking.


Enhanced detection of reactive oxygen species produced by human spermatozoa with 7-dimethyl amino-naphthalin-1, 2-dicarbonic acid hydrazide. A new chemiluminescence technique has been assessed for the detection of reactive oxygen species generated by purified populations of human sperm. This revised protocol involves the use of horse-radish peroxidase (HRP) in combination with a luminol analogue, 7-dimethyl amino-naphthalin-1,2-dicarbonic acid hydrazide (DNDH), that exhibits two-three times the quantal efficiency of luminol itself. The chemiluminescent signal generated with these reagents was significantly (P less than 0.001) greater than that obtained with the conventional luminol-based methodology for both the steady-state situation and following stimulation of the sperm with PMA and A23187. Dose-response analyses indicated that the DNDH/HRP chemiluminescence system could give linear standard curves with hydrogen peroxide concentrations into the nmol l-1 range. In contrast, the exponential rise in chemiluminescence recorded with luminol was not observed until hydrogen peroxide concentrations exceeded 10 mumol l-1. It is concluded that the enhanced sensitivity of the DNDH/HRP system to low levels of hydrogen peroxide should facilitate the application of chemiluminescent techniques to the diagnosis of oxidative stress in cases of male infertility.


Effect of isotypes of antisperm antibodies on semen quality. A direct immunobead test (IBT) was performed on 233 men who attended an immunological centre. Thirty-four (14.6%) of these men were found to be positive (greater than 20% binding) for antisperm antibodies (ASA). IgA, IgG and IgM were the most common sperm-associated immunoglobulins. In 50% of men with ASA asthenozoospermia, teratozoospermia, leukocytospermia or hypofunction of the seminal vesicles was observed. Semen parameters were altered most frequently when IgM was present in association with IgA and/or IgG. This suggests that there is an active inflammatory process in the reproductive tract, as evidenced by leukocytospermia, and this could be responsible for the abnormal semen parameters. ASA generation could be a consequence of this process rather than being the cause of the abnormal semen quality. If ASA do affect fertility, this could take place in the female reproductive tract.


Effect of zinc on human sperm motility and the acrosome reaction. This study has assessed the effect of zinc on human sperm motility and the acrosome reaction in vitro. Progressively motile human sperm were selected by swim-up and by glass bead columns and then incubated in a medium in which capacitation happened in an asynchronous way. Different doses of zinc (1, 10, 100 and 1000 microM) were added for periods of 2, 4 or 6 h. Other samples were incubated with zinc (1000 microM), and after 1 h incubation, the zinc was removed. Aliquots of each culture were used to evaluate progressive motility and the acrosome reaction using a triple-stain technique. Sperm motility was reduced when the amount of zinc added was greater than or equal to 100 microM, and these doses also caused a significant reduction in the % of sperm undergoing the acrosome reaction. After removal of zinc and further incubation in zinc-free medium for 1 h, an increase in the percentage of motile and acrosome-reacted sperm was observed. However, the increase in acrosome reaction did not reach the values observed in controls. Results suggest that extracellular zinc acts as an inhibitor of human sperm motility and the acrosome reaction (and/or capacitation and the acrosome reaction). This inhibitory effect is reversible and occurs in a dose-dependent fashion. The probable mechanisms involved are discussed.


Acidification of testicular and epididymal fluids in the rat after surgically-induced varicocele. Experimental left varicocele (ELV) in adult rats produces a bilateral increase in testicular blood-flow and temperature which may alter the intraluminal environment in which sperm mature. The purpose of the present study was to evaluate the effect of ELV on the in-situ pH, PCO2 and bicarbonate concentration ([HCO3-]) in seminiferous tubules (ST), initial segment (IS), proximal caput (PCP), middle caput (MCP), middle corpus (MCR), and proximal cauda epididymidis (PCD) of the rat employing pH and PCO2 microelectrodes. Adult male rats with ELV or sham-surgeries (control) were studied after 30 days. Relative to controls, ELV significantly reduced the in-situ PCO2 in the testicular artery, ST, IS, PCP, MCP, MCR and PCD. In spite of this reduction, all values remained significantly higher than the systemic arterial blood PCO2. Values for in-situ pH in ST, IS, PCP, MCP, MCR, and PCD of control rats were significantly more acidic than systemic arterial blood. Furthermore, ELV decreased the pH in ST, IS, PCP, and MCP when compared to control values. The calculated [HCO3-] in ST from control animals was less than half that in systemic arterial blood and was reduced further in IS, PCP, and MCP. Varicocele did not change the [HCO3-] in systemic arterial blood but reduced markedly the values in ST, IS, PCP, and MCP. These alterations in the in-situ pH, PCO2, and [HCO3-] in structures of the rat testis and epididymis may play a role in the anti-spermatic effect of ELV.


Effects of induced peripheral anosmia on gonadal maturation in prepubertal male rabbits. The effect of induced peripheral anosmia on gonadal development and maturation was investigated in sexually immature male rabbits. Furthermore, the effect of agents promoting gonadal maturation (LHRH, hMG or methyl testosterone) on testicular development was examined in anosmic rabbits. Peripheral anosmia was induced by spraying the olfactory mucosa with 5% ZnSO4 solution; its effects were evaluated after a 45-day period, corresponding to the duration of spermatogenesis. Evaluation was based on measurement of body-weight, testicular size, testicular biopsy score count (TBSC) and a standard LHRH test (0 and 30 min) involving measurement of the blood levels of FSH, LH and testosterone before and at the end of the test. Markedly lower final and incremental values were noted in anosmic, compared to intact, animals for body-weight (P less than 0.001), TBSC (P less than 0.001), FSH (P less than 0.01) and LH (P less than 0.05). On the other hand, treatment of the anosmic rabbits with 0.9% saline, resulted in lower FSH, TBSC and testicular size increments than in rabbits treated with LHRH, hMG or testosterone, while testosterone levels and body-weight increments were similar in all groups. These findings indicate that induced peripheral anosmia is probably responsible for the inadequate gonadal maturation in prepubertal anosmic male rabbits. This relationship was confirmed by the observed stimulatory effect of administration of agents activating pituitary gonadotrophin secretion or gonadal function in anosmic animals.


Possible involvement of the accessory sex glands in the regulation of pituitary hormones. A time-course alteration in the blood levels of gonadotrophin was evaluated in male rats aged 49 days after: (a) removal of the seminal vesicles, (b) bilateral orchidectomy, or (c) bilateral orchidectomy together with removal of the seminal vesicles. Age-matched sham-operated animals served as controls. Removal of the seminal vesicles resulted in elevation in the blood levels of LH, FSH and prolactin compared to controls. As expected, bilateral orchidectomy also resulted in the elevation of serum gonadotrophins. In the absence of both the seminal vesicles and the testes, LH and FSH levels were increased further compared to orchidectomy alone. Thus the present study suggests the presence of a feedback mechanism between the seminal vesicles and pituitary which is more pronounced in the absence of the testes.


Isolation and culture of testicular macrophages from a seasonally breeding species, Phodopus sungorus. Evidence for functional differences between macrophages from active and regressed testes. We have developed an isolation and cultivation protocol for testicular macrophages from the seasonally breeding Siberian hamster, Phodopus sungorus which allows serum-free culture. Macrophages were isolated from the active testes of adult Phodopus kept in long photoperiod (LD, 18hL:6hD), and from the inactive testes of animals with gonadal regression induced by exposure to a short photoperiod (SD, 6hL;18hD; for 10 weeks). The isolated cells were identified as macrophages by (a) electron microscopy, (b) non-specific phagocytosis, and (c) the presence of Fc-receptors. Treatment of the cultures with oFSH (at 0.5 and 1 micrograms ml-1 for 1 and 4 days) significantly stimulated lactate secretion by testicular macrophages from LD hamsters, as expected from studies in the rat. In marked contrast, oFSH did not affect lactate secretion by testicular macrophages from SD hamsters, or by peritoneal macrophages. To test possible macrophage-Leydig cell interactions, the influence of testicular macrophage-conditioned medium (TM-CM) from FSH-responsive LD macrophage cultures was assessed and compared with the effect of peritoneal macrophage-conditioned medium (PM-CM) on testosterone production by testicular parenchyma from LD hamsters. Unexpectedly, and in contrast to previous reports in rats, testosterone production by testes was inhibited significantly by TM-CM from cultures pretreated with either 0.1 or 0.5 micrograms FSH ml-1. FSH alone stimulated testosterone production (due either to LH contamination or to possible paracrine effects). PM-CM from cultures pretreated with FSH did have an inhibitory effect. It is concluded that: (i) There is indirect evidence for the presence of functional FSH receptors on macrophages from the active testes of Phodopus. (ii) Testicular macrophages from inactive testes of Phodopus are not responsive to FSH, implicating impaired macrophage function in the regressed testes of Phodopus exposed to SD. (iii) Testicular macrophages produce a factor which can inhibit testosterone production by incubated testicular tissue.


Model-based decision support system for individual prescription of the dialysate bicarbonate concentration in hemodialysis. A decision support system has been developed that determines the optimal dialysate bicarbonate concentration in hemodialysis therapy for each patient individually. The knowledge about the behavior of the acid-base state during treatment has been provided by a mathematical model for the description of dynamic exchange processes during hemodialysis. This model simulates the sodium and water distribution, the acid-base state as well as the ventilation. The decision support system uses the model for the prediction of the end-dialysis acid-base state and calculates by means of linear optimization the dialysate bicarbonate concentration which is necessary to reach a specified end-dialysis state. If the aspired acid-base state can not be reached, the system varies the dialysate sodium concentration and the treatment time. The whole program can be used on a PC and is easy to use. One decision making process lasts between 10 seconds and 5 minutes depending on the computer.


Biocompatibility of high-flux membranes. Standard dialysis with cuprophane membranes is known to stimulate the immune system. As a result of activation of macrophages various interleukins and tumor necrosis factor (TNF) are secreted, presenting further evidence of the poor biocompatibility of cuprophane. We investigated the immunogenic properties of three modern high-flux membranes. Seven patients were studied during hemodiafiltration sessions using either a polysulfone (F60, Fresenius), a polymethylmetacrylate (BK 2.1, Toray) or a cellulose triacetate (FB-210 U, Nipro) dialyzer in a hemodiafiltration procedure. Serial measurements were made during each treatment of interleukin-1 beta (II-1 beta), TNF, soluble IL-2 receptor (sII-2r), soluble CD4 (sCD4), soluble CD8 (sCD8), interferon gamma (IFNg) and neopterin. In contrast to the known increase of IL-1 beta, IL-2r and TNF with cuprophane membranes, none of the modern high-flux dialyzers stimulated the production of these factors. Significant decreases of neopterin and sCD4 were observed. IFNg and sCD8 did not change significantly. Our results suggest that the modern high-flux dialyzers are non-immunogenic, and thus provide further evidence of the superior biocompatibility of synthetic or semisynthetic membranes over the conventional cuprophane.


Disinfection of regenerated dialyzers with ozone. Regenerated, ozone-disinfected dialyzers were use for a total of 190 hemodialyses in 35 patients without the occurrence of any complication or pyrogen reactions; the efficiency of hemodialysis was identical with that of new or formalin-disinfected dialyzers. The priming fluid contained in both compartments of ozone-disinfected dialyzers proved to be sterile. The ozone did not damage the dialyzer membrane or the supporting structure of dialyzer. Ozone can effectively substitute formalin and other chemical sterilants as a disinfectant of regenerated capillary dialyzers. The process can also be automated.


Differences between KT/V measured during dialysis and KT/V predicted from manufacturer clearance data. We retrospectively analyzed data from 3,863 dialysis treatments in 329 end-stage renal disease patients over a period of 33 months to evaluate the accuracy of in vitro KT/V estimated by manufacturer's urea clearance data in relation to in vivo measured KT/V. In 1,087 urea clearances measured, mean actual clearance was 87% of predicted. At all blood flows, actual clearances were significantly lower than predicted (8-16% lower than predicted). In 2,807 KT/V measurements, predicted KT/V was 1.238 +/- 0.005 whereas the mean of actual measured KT/V was 16% lower or 1.024 +/- 0.005 (P less than 0.0001). At different blood flows and with different dialyzers, predicted KT/V overestimated actual values. With increasing numbers of reuse, actual/predicted clearance ratios and actual/predicted KT/V ratios progressively dropped. Prescribing dialysis treatments using manufacturer's in vitro generated clearance data can lead to marked underdialysis of patients.


Blood flow rate and access recirculation in hemodialysis. We studied the effect of extracorporeal blood flow rate (BFR) on access recirculation (recirc) in 19 hemodialysis patients. BUN was determined in simultaneous peripheral (P), arterial (A), and venous (V) blood obtained at BFRs of 200, 400, and 600 ml/min. Percent recirc was calculated for each BFR using the formula (P-A)/(P-V) x 100. Venous drip-chamber (VP) and pre-blood-pump (AP) pressures were measured at each BFR. Fistulograms were performed in 10 patients, and stenoses were identified in 5, all at the proximal (arterial) end of the access. Recirc increased with increasing BFR from 200 to 400 ml/min but increased little from 400 to 600 ml/min. At all BFRs recirc in the stenotic patients was higher than that of non-stenotic or unstudied patients. Urea clearance, corrected for recirc, rose with blood flow both in stenotic and non-stenotic patients. There were no differences in AP or in VP between stenotic and non-stenotic patients. At BFR greater than or equal to 400 ml/min, a recirc threshold of 15% identified stenoses with sensitivity 100% and specificity 71%. We conclude (1) recirc increases with increasing BFR but not enough to outweight the concomitant increase in urea clearance; (2) significant access stenosis and recirc may be present even with low VP; (3) recirc was associated with arterial side stenoses; (4) at BFR greater than or equal to 400 ml/min, access stenosis is associated with recirc greater than 15%.