The prediction and control of behavior revisited: a review of the matching law. Experimental research conducted over the past 3 decades in relation to behavioral allocation and choice, collectively known as matching law research, is analyzed in this paper. The importance of the matching law for areas ranging from experimental to clinical psychology and psychiatry is discussed in relation to empirical findings that bear upon the validity and utility of the matching law for both the prediction and control of human behavior as well as for psychological and scientific inquiry in general.


Attitudes of Arabic psychology students toward behavior modification. Several American studies have investigated attitudes toward behavior modification. As there are no data on perceptions of this approach in other countries, this study was undertaken to examine such attitudes in Arab countries. The attitudes of 102 undergraduate psychology students at the University of Jordan were assessed. The results showed that behavior modification is favorably received. No significant differences were found between male and female students, or among second, third, and fourth year students. However, significant differences were found between students who had taken a behavior modification course and those who had not.


Skin temperature biofeedback: evaluation of non-clinical children's responses. The present study evaluated the extent to which children are able to learn to increase skin temperature with biofeedback training. Forty-nine children (ages 7-16) were randomly assigned to either standard biofeedback, novel biofeedback or control groups, which met for 16, 16, and 5 sessions, respectively. Results indicated children in the novel biofeedback group significantly increased their skin temperature as compared with the control group. The biofeedback groups exhibited significant skin temperature control during feedback. Results provide normative data on what to expect from children receiving skin temperature biofeedback.


Behavioral intervention to reduce water intake in the syndrome of psychosis, intermittent hyponatremia, and polydipsia. We describe a non-intensive behavioral intervention using an A-B design with extended follow-up on an open psychiatric unit to reduce water intake in a 52-year-old man with the syndrome of psychosis, intermittent hyponatremia, and polydipsia. A reinforcement schedule contingent upon weight gain secondary to water intake was employed. Mean diurnal weight gain was 7.1 pounds during a 23-week baseline which dropped to 4.1 pounds following 23 weeks of treatment and at a 1-year follow-up. Estimated fluid consumption dropped from 10 liters to 4 liters daily and incidents of hyponatremia decreased by 62%.


The efficacy of rational emotive therapy in adults: clinical fact or psychometric artifact? The efficacy of Rational-Emotive Therapy (RET) in reducing maladjustment, while insistently touted by its advocates, has not been unambiguously demonstrated in outcome research. Previous reviews have generally been quite partisan and subjective, and have not reflected available research. The object of the present review was to determine the extent to which RET significantly improved adjustment of adult subjects on different outcome measures in comparison with wait-list, placebo, and other treatment conditions. In 75 outcome reports, RET was effective in only about 25% of comparisons. Its main effect was to reduce scores of self-reported irrationality and dysphoria. Little change was noted in behavioral measures. The few comparisons favoring RET could be attributed to psychometric artifacts rather than to the reduction of irrational beliefs.


Monoclonal antibody JC1: new reagent for studying cell proliferation. To characterise a newly developed mouse monoclonal antibody JC1 which recognises a nuclear antigen present in proliferating cells in normal tissues and neoplastic lesions, and which is absent in resting cells. The methodology was established using a representative range of frozen sections from normal tissues and from certain tumours which were immunostained with antibodies Ki67 and JC1. The molecular weight of the antigen recognised by JC1 was obtained by western blot analysis and this was compared with that of Ki67. IM-9 cell lysates containing Ki67 derived plasmids were also tested with JC1 antibody. Biochemical investigation indicated that the antigen recognised by JC1 gives two molecular weight bands of 212 and 123 kilodaltons, which is distinct from the well characterised anti-proliferation monoclonal antibody Ki67 (395-345 kilodaltons). In addition recombinant Ki67 protein is not recognised by JC1. Immunohistological reactivity was seen in areas known to contain numerous proliferating cells such as lymphoid germinal centres, splenic white matter, cortical thymocytes and undifferentiated spermatogonia. In tumours many cells from adenocarcinomas, oat cell carcinomas, squamous cell carcinomas of lung, and seminomas were labelled by JC1 with a distribution and proportion similar to that seen with Ki67. In normal tissues the only apparent difference was in testis where JC1 stained a considerably greater number of cells than Ki67. In all cases studied the new antibody showed nuclear reactivity only. JC1 did not show any cytoplasmic crossreactivity with squamous cells as is frequently seen with Ki67. Antibody JC1, which recognises a nuclear antigen present in proliferating cells, should provide a useful adjunct to Ki67 as a marker of proliferation especially in those cases such as squamous cell carcinomas where a Ki67 index cannot be determined.


Demonstration of HIV-1 infected cells in human placenta by in situ hybridisation and immunostaining. To show the presence of HIV infected cells in the placentas and membranes exposed to HIV during pregnancy, and to trace the possible transmission routes from mother to fetus. Twenty three therapeutic abortions and 11 term placentas were investigated for the presence of HIV antigen by immunostaining with HIV core protein specific antibodies and HIV nucleic acids by in situ hydridisation (ISH) with a 35S-labelled HIV specific RNA probe. HIV antigen as well as HIV RNA positive cells were rarely found in placental tissue and membranes. In therapeutic abortions HIV antigen was shown in 10 out of 23 placentas, HIV RNA in two. HIV antigen was detected in five out of 11 term placentas and HIV RNA in two. Infected cell types comprised syncytiotrophoblasts, Hofbauer cells, amnionic epithelium, chorionic macrophages as well as maternal lymphocytes in the intervillous space and decidua. These data suggest that the transmission routes are: (1) a haematogenous route from the maternal intervillous space to villous stromal cells; (2) from chorion laeve to amnionic fluid and vice versa. Two additional transmission routes are partly suggested by the data: (1) in early gestation by direct extension from basal decidua to budding trophoblastic cells; (2) from the capsular decidua to chorion laeve and chorionic plate, entering the fetal circulation via the small veins.


Cell sizing in chronic lymphoproliferative disorders: an aid to differential diagnosis. To determine if leucocyte volume distribution analysis (LVDA), obtained using a Coulter Counter Model S Plus IV, can be used to aid differentiation of chronic lymphoproliferative disorder (CLPD) subtypes. Mean lymphocyte volume and lymphocyte distribution width were measured on each patient (n = 90) using a hard copy of an amplified LVDA histogram. The mean lymphocyte volume was taken as the mean of the values on either side of the peak at half maximum height. The lymphocyte distribution width was taken as the range of cell values between the two values used to calibrate the mean lymphocyte volume. A template showing typical histograms from commonly occurring CLPD was also produced on an acetate sheet. This was used to examine the histogram from each new patient to evaluate its usefulness as an alternative to the calculation of mean lymphocyte volume and lymphocyte distribution width. Mean lymphocyte volume and lymphocyte distribution width were significantly higher in B cell lymphocytic leukaemia of mixed cell type (B CLL/PL), B cell non-Hodgkin's lymphoma with peripheral blood spill, hairy cell leukaemia and T cell prolymphocytic leukaemia than in B cell chronic lymphocytic leukaemia (B CLL). The mean lymphocyte volume, but not the lymphocyte distribution width, was also significantly higher in T cell chronic lymphocytic leukaemia than in B CLL. The template gave an immediate preliminary indication of possible subtype(s) of disorder and could be used as an alternative to measurement of mean lymphocyte volume and lymphocyte distribution width. Electronic haematology analysers producing an LVDA provide a useful, cost effective cell sizing analysis which can aid the differentiation of subtypes of CLPD.


ICAM-1 expression in renal disease.

ICAM-1 expression in renal disease. To determine the role of intercellular adhesion molecule-1 (ICAM-1) in immune mediated damage in glomerulonephritis, and whether its expression correlates with disease activity. Fifty three renal biopsy specimens from a range of non-immune renal disease and low grade and high grade glomerulonephritides were stained with ICAM-1. Positivity was assessed in the tubules. Tubular damage and accompanying interstitial inflammation were also noted. The ICAM-1 positivity in damaged and undamaged tubules was correlated with the three groups of renal disease. ICAM-1 positivity in undamaged tubules was observed in glomerulonephritis, and this showed a strong correlation with disease activity. In contrast, ICAM-1 positivity on damaged tubules correlated with evidence of chronic tubular damage, and was seen in a large proportion of cases, regardless of the underlying disease. There was no correlation between ICAM-1 positivity and a local lymphocytic infiltrate. ICAM-1 probably has an important role in the pathogenesis of glomerulonephritis. Its expression may be secondary to cytokines released by cells participating in the glomerular damage. As these cytokines also influence tubule function, tubular ICAM-1 expression may be a marker of the extent of tubular disturbance in glomerulonephritis.


Nucleolar organiser regions (AgNORS) in anal intraepithelial neoplasia and invasive anal squamous cell carcinoma. To evaluate the usefulness of counting nucleolar organiser region associated proteins (AgNORs) in the management of anal squamous neoplasia. Using a silver staining technique for NOR associated proteins, 32 routinely processed paraffin wax embedded sections of anal epithelium were assessed. These consisted of normal anal epithelium (n = 9), anal intraepithelial neoplasia (AIN) grades I (n = 5), and III (n = 13), and invasive squamous neoplasia of the anus (n = 5). The median AgNOR counts for every 100 cells are as follows: normal anal epithelium 2.15 (95% CI 1.89-3.94); AIN I 3.21 (95% CI 2.89-7.14); AIN III 4.32 (95% CI 4.00-8.10); and invasive squamous cell carcinoma of the anus 5.51 (95% CI 2.48-10.62). There were significant differences between AgNOR counts in anal cancer and normal epithelium (p < 0.05; Mann-Whitney U test)), AIN III and normal anal epithelium (p < 0.005), and AIN III and AIN I (p < 0.05). No significant differences were observed between AIN I and normal anal epithelium, anal cancer and AIN I, and anal cancer and AIN III. There was a considerable degree of overlap among the different groups. Despite the strong association between AgNOR values and degree of dysplasia, the variability within pathological grade may preclude the adoption of this technique on its own as a prognostic indicator. It may, however, be useful in conjunction with other markers of neoplastic growth such as c-myc oncogene amplification or overexpression as a marker of disease progression in AIN and invasive anal squamous cell cancer.


Nasopharyngeal carcinoma in situ in nasopharyngeal carcinoma. To assess the presence of carcinoma in situ (CIS) in patients with nasopharyngeal carcinoma (NPC) and to see if the number of biopsy sites facilitates detection of CIS. Formalin fixed, paraffin wax embedded biopsy specimens (n = 285) from 187 patients with NPC in 1987 were studied for the presence of CIS as well as for the histological assessment of the subtype of CIS. Fifteen (8.0%) patients had CIS, representing 8.3% of all new patients with NPC and 11.6% of patients with persistent disease or relapse. CIS was undifferentiated or poorly differentiated, no cases of well differentiated squamous cell CIS were identified. There was no significant difference in the incidence of CIS when multiple endoscopic biopsy specimens were taken rather than single forceps biopsy specimens. CIS can only be identified in a few patients with NPC largely because of late presentation with advanced disease at the time of diagnosis and the focal nature of the dysplastic process. The presence of dysplasia in relapses of NPC suggests that these tumours may be second growths rather than regrowths of a primary tumour.


Modified latex agglutination test for antibodies to Toxoplasma gondii in eluates from Guthrie cards. To determine whether the Eiken particle agglutination test could be modified to make it sufficiently sensitive to screen blood samples collected on Guthrie cards for the presence of antibodies to Toxoplasma gondii; to evaluate the specificity of the modified system; and to compare seroepidemiological data on the prevalence of T gondii in pregnant women. Simulated dried blood spots were prepared from sera from pregnant women booking for antenatal care. Eluates from the simulated dried blood spot cards and sera were tested in parallel using the modified test (1 in 5 dilution of latex) and the standard assay (neat latex particles) and endpoints determined. Guthrie card eluates, from neonates in three Thames regions, were then tested using the modified test. The modified test produced a 4.21-fold increase in antibody titre in 85 sera when tested in parallel with the standard test. Eluates of 168/170 from simulated dried blood spots derived from seropositive patients gave a positive result in the modified test. The two eluates which gave a negative result were derived from patients with an equivocal titre of 1/16 in the standard serum test. Of the eluates derived from serum negative patients all 103 were negative at a dilution of 1 in 4 in the modified test. The seroprevalence of antibodies to T gondii in pregnancy was 21.8% using the standard test. A similar value of 20.5% was obtained when dried blood spots from neonates in a similar region of London were tested by the modified test. The modified Eiken Toxo-reagent test is sensitive, simple, and economic for screening large numbers of dried blood spots. The procedure could be easily semiautomated and the technique applied to the mass screening of neonatal blood samples collected on Guthrie cards to determine the seroprevalence of T gondii in pregnant women.


Use of the polymerase chain reaction to detect Toxoplasma gondii in human blood samples. To assess the value of detecting Toxoplasma gondii in human blood samples using the polymerase chain reaction (PCR). Blood samples in lithium heparin were examined from 34 patients with suspected toxoplasmosis, and six healthy volunteers with or without the addition of doubling dilutions of toxoplasma tachyzoites. Products of a nested PCR, using oligonucleotide primers of the B1 gene, were analysed by electrophoresis and stained by ethidium bromide. The primary product was 194 base pairs in length; the nested products were 160 or 97 base pairs. When toxoplasma tachyzoites were added to the leucocytes of six different volunteers, eight to 16 parasites were detected by nested PCR in one experiment and one to four parasites in eight experiments. All nine experiments were negative in samples without added tachyzoites. Of 34 patients, PCR was negative in 13 with recent lymphadenopathy; nine with persisting IgM, including two pregnant patients; four with reactivated infection due to immunodeficiency; and five with no evidence of active infection. Positive PCR results were found in three patients with reactivated infection. There was only one discrepancy between PCR and animal culture results; this was in an immunocompromised patient with a positive PCR and negative culture. The PCR technique was rapid, sensitive, and specific in human blood samples. Negative PCR results in patients with persisting IgM suggested that the fetus was not at risk, or that treatment was not indicated in myalgic encephalomyelitis-like illness. PCR results in immunocompromised patients permitted appropriate management--no treatment if negative, treatment if positive.


Laboratory examination for Cryptosporidium spp in Scotland. To ascertain the present practices of Scottish microbiological laboratories for examining faecal samples for Cryptosporidium spp and to compare these with practices elsewhere. A questionnaire was circulated to all 35 Scottish NHS bacteriological laboratories, where human stool samples are subjected to routine microbiological examination, to determine current laboratory testing methods and selection criteria used to examine faecal specimens for Cryptosporidium spp. All laboratories responded, of which the first began testing in 1984 and the last in 1990. At 15 sites all diagnostic stool samples submitted are routinely examined for Cryptosporidium spp. Elsewhere, selection criteria, principally based on age, specific request, and foreign travel, are used. The age distribution of Scottish cases differed significantly from that of the PHLS study of 16 laboratories (p < 0.001), probably as a result of the selection criteria used. The phenol-auramine staining procedure is used by 19 laboratories, with modified Ziehl-Neelsen staining used by 14 laboratories; eight used a second, confirmatory method. Currently applied selection criteria for examination of stools for Cryptosporidium in Scotland do not accord with published epidemiological data. Specimen selection based on age of patient and stool consistency may lead to cases of public health importance being missed. Nationally agreed criteria for testing of human samples based on epidemiological evidence are required.


Antithrombin III deficiency and cerebrovascular accidents in young adults. A young man with antithrombin III (AT-III) deficiency sustained a cerebellar venous infarct and recovered following treatment with AT-III concentrate. A family study showed that other members were affected. AT-III deficiency in this family was found to be due to a new variant AT-III TRURO 1. Young patients with strokes should be screened for thrombophilia.


Tissue artefacts caused by sponges.

Tissue artefacts caused by sponges. Artefacts which occur during the processing of small biopsy specimens can cause sufficient tissue distortion to impair interpretation and can be a considerable source of nuisance. Triangular artefacts were noted in renal and liver biopsy specimens which were caused by foam sponges in embedding cassettes. Scanning electron microscopic examination of the sponges showed they comprised a mesh of scimitar-shaped rigid spikes which closely match the artefacts seen in the tissues.


Alternative method of sampling placentas for the assessment of uteroplacental vasculature. A new method for the taking and embedding of placental blocks to obtain maximum information regarding the uteroplacental vasculature was developed. This method involves taking en face blocks of the basal plate of the placenta. Results show that normal and abnormal maternal vessels are clearly delineated. In addition to conventional full thickness blocks, which provide information about the chorionic plate such as inflammation and meconium pigment uptake, and about the parenchyma in the other zones remote from the basal plate of the placenta, it is recommended that en face blocks be taken for histological assessment of the placenta.


Tubulovillous adenoma arising 30 years after ileocystoplasty. The possibility of recurrent colonic metaplasia occurring as a complication of pelvic ileal pouches after ileo-rectal anastomosis has been raised. Several reports have documented malignant bladder tumours developing in patients many years after an ileocystoplasty. The case of a 50 year old man, who developed a tubulovillous adenoma in the ileal patch 30 years after an ileocystoplasty had been performed to enlarge a tuberculous shrunken bladder, is reported. The adjacent small intestinal mucosa showed features suggestive of colonic metaplasia.


Abnormal haemoglobin electrophoresis caused by BW 12C. BW 12C, a substituted benzaldehyde, stabilises haemoglobin in the oxy-conformation and has attracted interest as an anti-sickling agent. The drug causes a left shift in the oxygen saturation curve and may induce tumour anoxia and enhance the effect of cytotoxic drugs. During clinical trials in patients with cancer abnormal bands on haemoglobin electrophoretic strips were observed. This made correct diagnosis of abnormal haemoglobins impossible. Solubility tests for sickling disorders (Itano) also proved unreliable.


Diagnosis of toxoplasma infection in cardiac transplant recipients using the polymerase chain reaction. Cardiac biopsy samples taken from transplant recipients around the time of primary toxoplasma infection were investigated by conventional histology and amplification of the P30 gene of Toxoplasma gondii by the polymerase chain reaction (PCR). Toxoplasma was detected more frequently by PCR than histology which may reflect the enhanced sensitivity of the former technique. Further studies are required to determine the optimal amount of tissue which should be examined by each technique and to develop a PCR assay capable of distinguishing between quiescent infection and active toxoplasmosis.


Renal AA amyloidosis in a patient with Bence Jones proteinuria and ankylosing spondylitis. A patient with a 10 year history of monoclonal gammopathy of undetermined significance and Bence Jones proteinuria, and a 44 year history of ankylosing spondylitis, developed a nephrotic syndrome secondary to renal amyloidosis. Clinically the amyloidosis was ascribed to Bence Jones proteinuria rather than to the burnt out ankylosing spondylitis. However, histochemical and immunofluorescence staining techniques used to type the amyloid fibrils showed AA amyloidosis, implicating ankylosing spondylitis rather than monoclonal gammopathy as the underlying cause of the patient's systemic amyloidosis and consequent nephrotic syndrome. It is recommended that immunostaining of amyloid become a routine procedure to detect occult or apparently inactive disease.


Lobular carcinoma in a mammary hamartoma. Mammary hamartomas are uncommon breast lesions, sometimes presenting as mammographic abnormalities which require pathological clarification. Previous cases have all been benign. A unique case of mammary hamartoma containing atypical lobular hyperplasia (ALH), lobular carcinoma in situ (LCIS), and foci of microinvasive lobular carcinoma is presented. The need for adequately sampling macroscopically innocuous breast lesions is emphasised.


A computer-assisted method for making linear radiographic measurements using stored regions of interest. Accurate detection of changes in alveolar bone height requires radiographic measuring methods with a reliability of standard deviation (SD) of 0.15 mm or better. No periodontal digital imaging system has reached this reliability, although 3 analogue methods have achieved this goal. However, existing linear methods are time-consuming, difficult to use, unsuitable for measuring all possible (unsharp) anatomical sites and do not provide a confidence estimate for sites of change observed in serial standardized films. A rapid computer-assisted method using stored image regions of interest (ROI) has been developed which allows retest measurements for all possible sites and automatically calculates a 90%, 95%, 98%, or 99% confidence threshold value, derived from duplicate measurement variation, for sites of apparent crest height change. 28 examiners, with minimal training in operating the system, measured 14 different cement-enamel junction to crest height distances from a standard bitewing image, with and without the ROI method. The measurements were repeated 4 weeks later. 13/14 sites achieved an intra-examiner SD threshold of less than or equal to 0.15 mm with the ROI method but 0/14 without. A higher inter-examiner SD threshold of less than or equal to 0.22 mm was achieved for 13/14 sites using ROI and 0/14 without (p less than 0.001). The measurement of crest height changes in a region of previous severe vertical bone loss is demonstrated using serial films. The potential for using trabecular bone patterns as reference sites in regions where traditional measurement points are absent is demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)


Effects of ultrasonic and sonic scalers on dental plaque microflora in vitro and in vivo. The effects of ultrasonic and sonic scalers on the subgingival microflora were investigated in vitro and in vivo. In the in vitro investigation, 27 plaque samples collected from periodontal pockets were submitted to ultrasonic and sonic vibrations for 10, 30 and 60 s. Bacterial suspensions were examined by darkfield microscopy to detect qualitative changes and cultured to evaluate the total number of cultivable bacteria. Microscopic counts following both instrumentations showed a decrease in the proportions of spirochetes and motile rods and an increase in the % of coccoids and rods. The changes were directly related to the time-period of instrumentation. Comparison between both types of instrumentation showed significant differences and more pronounced changes were observed with the ultrasonic than the sonic scaler. Spirochetes and motile rods were reduced to approximately 0.1% after ultrasonic treatment versus 24.7% after sonic instrumentation. Cultural observations showed a marked increase in total number of colony-forming units following both treatments. The clinical investigation included 66 periodontal pockets which were instrumented subgingivally for 10 and 30 s with ultrasonic or sonic scalers. Qualitative changes were similar to those observed in vitro, i.e., reduction in spirochete and motile rod counts as well as the other morphotypes with an increase in coccoid cells. Total counts of bacteria were reduced following debridement. No difference in the microscopic or cultural data was found between ultrasonic and sonic instrumentation.


Cleaning effectiveness of chewing sticks among Tanzanian schoolchildren. The oral hygiene of habitual chewing stick and toothbrush users who participated in an oral health education (OHE) programme in schools was evaluated. The study comprised all chewing stick users (n = 45) in standard 4 in 8 randomly selected experimental schools and all chewing stick users (n = 17) in standard 4 in 4 randomly selected control schools. Each chewing stick user was randomly matched with a toothbrush user of the same sex, age and school. Their ages ranged from 10 to 13 years with a mean of 11.5 years. The children in standard 4 of the 8 experimental schools received OHE. Among many topics aiming to improve oral health of children, the practice of systematic brushing was taught. The children practised weekly brushing sessions in schools under the supervision of instructed teachers. At baseline, the chewing stick users exhibited statistically significant more plaque, but their gingival condition was comparable with their matched toothbrush counter-parts. After 3 months, the chewing stick and the toothbrush users in the experimental schools, had reduced their plaque and gingival bleeding scores significantly to the same extent, whereas no substantial changes in oral hygiene occurred in the control group. The findings show that schoolchildren who participated in a school programme that emphasizes effective toothbrushing were able to improve their oral hygiene regardless of whether they were habitual chewing stick or toothbrush users.


Associations between volume and flow rate of gingival crevicular fluid and clinical assessments of gingival inflammation in a population of British male adolescents. Gingival crevicular fluid (GCF) sampling was performed on 2 occasions separated by 1 year, at 2 sites in the mouths of 102 male adolescents, mean age 17.85 years. Samples were collected onto 5 filter paper strips which were sequentially applied to the mouth of the crevice over a 9-min collection period. Volume and flow rates of GCF were determined for each site and were compared with clinical measurements of plaque, gingival colour, bleeding, gingival index (GI) and pocket depth, using a general linear models (GLM) procedure. While the initial volume of GCF showed no association with any clinical measurement, there was an association between flow rate of GCF and gingival colour. The volume of GCF collected in the final, 5th sample was associated with the GI. The sample site strongly influenced all measures of GCF volume. It is proposed that the flow rate of GCF may be a better indicator of gingival inflammation than the more imprecise clinical assessments of inflammation, since GCF flow rates more precisely reflect changes in tissue permeability. The association between the final sample, collected after 9 min, and clinical measurements, was probably a reflection of the association between clinically-detectable inflammation and the susceptibility of the site to mild irritation.


Bleeding on probing as it relates to probing pressure and gingival health in patients with a reduced but healthy periodontium. A clinical study. A previous study demonstrated that the bleeding on probing (BOP) test using uncontrolled forces may result in a proportion of false positive readings when used as a parameter for inflammation. A strong possibility exists for the traumatization of clinically healthy gingival tissues if a probing force exceeding 0.25 N is applied. While these results originated form young dental hygienists exhibiting excellent oral hygiene, the aim of the present study was to evaluate the relationship between probing pressures and gingival conditions in patients with a history of treated periodontal disease, i.e., in situations with a reduced but healthy periodontium. 10 patients who had been enrolled in a periodontal maintenance program following treatment of moderate to advanced chronic inflammatory periodontal disease consented to participate in the study. They were all selected on the basis of a record of excellent oral hygiene practices for at least 2-6 years and almost complete absence of clinical inflammation following successful periodontal therapy. Applying a probing force of 0.125, 0.25, 0.375 and 0.5 N in the 4 jaw quadrants, respectively, at 2 different occasions with an interval of 10 days, bleeding on probing was assessed. Oral hygiene and gingival conditions were determined using the criteria of the plaque and gingival index systems. All subjects showed significant increases in mean BOP% with increasing probing force applied (2.5%-7.9%). Regression analysis revealed an almost linear correlation and a significant correlation coefficient between BOP% and probing force. Almost identical slope inclinations were found when the 6 subjects with the lowest mean BOP% at 0.25 N were compared with the regression analysis of the total group.(ABSTRACT TRUNCATED AT 250 WORDS)


The use of irradiated-crosslinked human collagen membrane in guided tissue regeneration. Irradiated glutaraldehyde-crosslinked human collagen membrane was evaluated for its effects on new attachment formation in clinical trials, using the principle of guided tissue regeneration (GTR). 19 adult periodontitis patients with 52 matched bilateral periodontal defects received scaling and polishing with oral hygiene instruction. The bilateral periodontal defects were treated by reflecting a flap with collagen membrane (test) or flap reflection alone (control). Plaque (P1I) and gingival index (GI) scorings, probing pocket depth (PPD) and probing attachment level (PAL) along with classification of furcation involvement (FI) and bony defects were made at pre- and post surgery (6 weeks, 3 and 6 months). Improvement of P1I and GI scores was seen in both test and control sites following the surgical therapy. Reductions in PPD and PAL were significantly (p less than 0.001) more pronounced at 6 months in the test sites compared to the controls. The 2 Class I furcations in the graft-treated teeth showed complete resolution, while the corresponding furcations in the control teeth showed incomplete closure. The use of human collagen membrane based on the GTR technique for treatment of human periodontal defects provided greater gain of clinical attachment than when flap surgery alone was undertaken.


Buccal attachment loss in Swedish adolescents. A case referent study was performed to identify factors connected with loss of buccal attachment in adolescents. The study group was identified among 18-year-olds who had participated 2 years earlier in a study of periodontal conditions in adolescents. The criterion for inclusion in the case group was buccal attachment loss (greater than or equal to 1 mm) in one or more sites. Information on 28 variables, identified earlier as being related to recessions, was collected in a clinical examination, interview and observation. The referent group consisted of 66 subjects and the case group of 71 subjects. The case group comprised 2 subgroups, one identified as having buccal attachment loss in 1987 and the other with attachment loss occurring in the years 1987-89. Statistical analyses, using the chi 2 test, logistic regression and a variance component model, were performed to detect factors related to buccal attachment loss. These factors were thin alveolar tissue, narrow width of the attached gingiva and presence of teeth with buccal displacement. The results indicate that the anatomy of the buccal alveolar process is related to the presence of buccal attachment loss in populations with a high level of oral hygiene. To evaluate the importance of possible risk factors or etiological factors for development of buccal loss of tooth support, prospective epidemiological or experimental studies are needed.


The relation between periodontitis and systemic bone mass in women between 46 and 55 years of age. It has been suggested that periodontitis and systemic bone mass might be related. In order to evaluate this possible relationship, we performed an intra-oral examination and measured lumbar bone mineral density (lumbar BMD) and metacarpal cortical thickness (MCT) in 286 female volunteers between 46 and 55 years of age. In addition, the alveolar bone height was measured on bite wing radiographs of the dentate subjects. Of the subject, n = 60 (21%) were edentulous. Compared to the dentate subjects, the lumbar BMD and MCT of the edentulous women were not significantly different. In the dentate subjects, no significant correlation was observed between the clinical parameters of periodontitis (mean probing depth, occurrence of bleeding after probing and number of missing teeth) and the bone mass parameters (lumbar BMD and MCT); nor was a significant relation observed between the bone mass measurements and alveolar bone height. We therefore suggest that systemic bone mass is not an important factor in the pathogenesis of periodontitis.


Gingivectomy versus flap surgery: the effect of the treatment of infrabony defects. A clinical and radiographic study. The aim of this paper was to compare the short-term results of gingivectomy (GV) and modified Widman flap (MWF) surgery in the treatment of infrabony defects. 14 patients with 68 bilateral infrabony defects were selected. At baseline, and 3 and 6 months postoperatively, assessments of oral hygiene, gingival conditions, bleeding on probing, probing pocket depth and attachment level, were recorded. Conventional radiograps were obtained in a way that assured a reproducible projection geometry. In a split-mouth design, one jaw quadrant was randomly treated with GV, while the contralateral with a MWF. The changes of the bone tissue were assessed by means of conventional and subtraction images by 2 observers. The interobserver agreement of the conventional and subtraction technique was studied. The majority of the sites demonstrated a significant improvement in gingival conditions and a reduction in bleeding. For both treatments, probing depths were reduced by an average of 3 mm, while a mean of 1.22-1.35 mm of probing attachment gain was obtained. The GV resulted in slightly more gingival recession (1.90 mm) than the MWF (1.60 mm). The radiographic examination demonstrated gain of bone in 7 defects treated with GV and in 9 defects treated with MWF. This study demonstrated that pockets associated with infrabony defects can be successfully treated by both treatment modalities. Furthermore, bone gain can occur after treatment but not in a predictable manner.


Periodontal diseases and HIV infection. A review of the literature. There have been many references in the literature to HIV-related periodontal diseases, which although poorly substantiated, seem to have established them as part of the expected range of HIV-associated conditions. The original studies have produced conflicting reports which may stem from shortcomings in design. Consequently, the picture remains confused with respect to the classification, epidemiology, microbiology, natural history and management of HIV-related periodontal diseases. Future studies should give greater attention to sampling methods, the use of control groups and defining criteria. This will allow comparison of data between centres and facilitate study of what may be an uncommon disease.


Remodelling of periodontal tissues adjacent to sites treated according to the principles of guided tissue regeneration (GTR). The aim of the present study was to assess the remodelling of alveolar bone adjacent to periodontal sites following therapy according to the principles of guided tissue regeneration (GTR) using computer-assisted densitometric image analysis (CADIA), and to compare the radiographic results to traditional clinical parameters. As required for digital subtraction analyses, periodically reproducible radiographs were obtained using a modification of the Rinn System and individual acrylic bite blocks for periodical identical radiographs. Ideally, a digital subtraction image from a site where absolutely no change in density had occurred would show a perfect cancellation of the structures. An average grey level value of 128 (the middle of the digitizer grey level range set by software) would show up at each pixel. Areas with grey levels < 128 in the subtraction image would indicate loss in density and grey levels > 128 would indicate increase in density. Within the subtraction images, areas were defined using the cursor to draw "regions of interest" (ROI) projected on the bony defect exposed to GTR covering the crestal bone as well as the region of potential "bonefill". The mean, median, the standard deviation and range of the grey levels of pixels within a particular ROI were calculated. Similarly sized ROI were drawn in bone areas not exposed to the GTR procedure serving as controls. The differences in the mean grey levels of all pixels within a particular ROI between the baseline, 3 and 12 months images were calculated for documentation of gain or loss in density. From 14 patients, standardized radiographs were available from baseline, 3 months and 12 months postsurgically, depicting one infraosseous defect before and after treatment according to the principles of GTR. The densitometric changes observed in these defects were compared to the clinically assessed changes measured at the site with the deepest baseline pocket depth. A mean clinical attachment gain of 2.36 mm after 3 and 3.22 mm after 12 months was measured. This was associated with a mean reduction in the PPD amounting to 3.36 mm and 3.79 mm, respectively. The changes in the level of the FGM were rather small considering the deep original mean PPD of 7.07 mm. Over the first months, a mean recession of 1.14 mm was observed which was followed by a coronal displacement of 0.43 mm. With respect to the remodelling of the alveolar bone adjacent to the defects assessed by means of CADIA, the most pronounced changes occurred when comparing the baseline to the 12 months radiographs.(ABSTRACT TRUNCATED AT 400 WORDS)


Validity issues in split-mouth trials.

Validity issues in split-mouth trials. The main purpose of the split-mouth design is to remove all components related to differences between subjects from the treatment comparisons. By making within-patient comparisons, rather than between-patient comparisons, the error variance (noise) of the experiment can be reduced, thereby obtaining a more powerful statistical test. Unfortunately, comparisons made on a within-patient basis have potential disadvantages. Treatments may have effects on experimental units other than those which they were assigned to (carry-across effects). Such effects cannot be estimated from split-mouth data. Neither can treatment effects be estimated. The estimable parameter in a split-mouth design is the treatment effect plus the sum of all carry-across effects. Unless a priori knowledge indicates that no carry-across effects exist, reported estimates of treatment efficacy are potentially biased. In the design of split-mouth clinical trials, potential gain in precision should be carefully weighed against a potential decrease in validity.


Periodontal status in insulin-dependent diabetic adolescents. A cross-sectional study was designed to evaluate the periodontal status of 85 12-18 year-old French adolescents with insulin-dependent diabetes (IDDM) and 38 healthy controls in the same age group. The clinical examination consisted of plaque control and gingival inflammation evaluation and probing attachment level. The interproximal marginal bone level was assessed with bitewing radiographs taken on the first molars and on areas presenting an attachment loss over 2 mm. Diabetic children had significantly more gingival inflammation than children without diabetes, in spite of similar plaque scores. No significant relation between gingival condition and age, Tanner's index, HbAlc level or disease duration could be demonstrated. None of the subjects had sites with attachment loss > or = 3 mm or radiographic signs of periodontitis.


Guided tissue regeneration using biodegradable membranes of polylactic acid or polyurethane. The purpose of the present investigation was to evaluate the use of biodegradable membranes of polylactic acid or polyurethane for obtaining regeneration following treatment of circumferential periodontal defects in monkeys with the "guided tissue regeneration" procedure. Orthodontic elastic bands were placed around selected test and control teeth in 4 monkeys in order to induce breakdown of the periodontal tissues. When the destruction of the supporting tissues had progressed to a level corresponding to approximately half the length of the roots, the elastic bands were removed. After 1 to 8 months, full thickness flaps were raised on the buccal and lingual aspects of both test and control teeth. The exposed root surfaces were scaled and a notch was prepared in the root surface at the level of the reduced bone crest. Membranes of polylactic acid or polyurethane were placed circumferentially around the test teeth, while no membranes were placed around the control teeth. The tissue flaps were then sutured in a coronally displaced position. The surgical procedures and sacrifice of the animals were scheduled to provide observation times of 1, 4 and 8 months. During the healing period, various complications such as recession of the flap margins and exposure or exfoliation of the membranes were noticed. The histological analysis showed that the amount of new connective tissue attachment on test and control teeth did not differ and was restricted to the most apical part of the lesions. The bio-degradable membranes could be identified in a few specimens, and they were always surrounded by an epithelial layer.(ABSTRACT TRUNCATED AT 250 WORDS)


Histological evaluation of surgically treated oral tissues after application of a photocuring periodontal dressing material. An animal study. At present no information is available about biological effects on oral tissues of the photocuring periodontal dressing Barricaid. This animal study examines histologically the tissue responses of surgical areas covered during 7 days with either Barricaid, the eugenol-containing dressing Ward's Wondrpak or the bionert control gel Carboxyl Methyl Cellulose. One group was studied immediately after the removal of the dressings; in the other group, further healing was permitted for another week. Results after 7 days indicate acute inflammatory reactions in the test areas without significant differences between the 2 periodontal dressing materials. The control areas showed to a lesser degree basically the same tissue response. In the 2nd week, generally all areas healed. After 14 days, no differences between test- and control sites could be detected. From a biological point of view, these findings suggest no contra-indication for application of this photocuring dressing material after periodontal surgery.


Endodontic infection and calcium hydroxide-treatment. Effects on periodontal healing in mature and immature replanted monkey teeth. Large experimental defects with marginal communication, and small isolated experimental defects were created on the root surfaces of extracted monkey lateral incisors with either open or closed apices. The pulp tissue was either infected or removed, and calcium hydroxide placed in the root canal. The teeth were then replanted and the healing pattern evaluated histomorphometrically after 20 weeks. From the results, it was concluded that (1) an intrapulpal infection promotes marginal epithelial down-growth on a denuded dentin surface irrespective of tooth developmental stage, and that (2) the periodontal healing potential after calcium hydroxide-treatment appears to be higher in teeth with open apices compared with teeth with closed apices, where ankylosis was promoted as opposed to teeth with open apices where significantly more reparative cementum was found.


Progression of periodontal disease in patients with mild to moderate adult periodontitis. The aim of the present study was to determine the progression rate of periodontal disease in patients treated for localized or generalized mild to moderate adult periodontitis. 52 patients with a mean age of 53.7 years (S.D. 12.6 years) were instructed in optimal home care procedures and exposed to initial periodontal therapy, before reconstructive therapy was initiated. Following completion of the prosthetic procedures, supportive therapy was offered to a limited extent and maintenance visits were irregularly scheduled corresponding to traditional dental care. Clinical periodontal parameters from 4 sites per tooth were assessed at the initial examination, at the time of reevaluation after initial therapy and at the re-examination after 8-years. Full sets of intraoral radiographs from the initial and the 8-year re-examination were analyzed with respect to changes in the radiographic alveolar bone height as a % of the total tooth length. As the result of the home care instructions, the mean plaque index (plaque control record) amounted to 21% at the end of initial periodontal therapy. 8 years later, the re-examination revealed a mean plaque index of 49% and a mean gingival bleeding index of 24%. At the initial examination, the 52 patients presented with an average of 18.7 teeth. During treatment, 26 teeth were sacrificed and 19 teeth were lost over the 8 years of supportive therapy. Bicuspids were the most frequent teeth to be lost over the observation period. As a result of initial therapy, the mean pocket probing depths decreased significantly. However, after 8 years, only minor differences were found when compared to the initial examination.(ABSTRACT TRUNCATED AT 250 WORDS)


Marginal bone level in the normal primary dentition. The aim of the present study was to establish the normal range for the radiographic distance between the cemento-enamel junction (CEJ) and the marginal bone level (MBL) in the primary dentition, and to relate this distance to various physiological and pathological factors. 128 children at the ages 7, 8 and 9 years took part in the study. Clinical and radiographic examinations of the mesial and distal surfaces of all primary molars and the distal surface of the primary canines were performed. The clinical examination included measurements of the amounts of plaque, bleeding on probing, probing depth and probing attachment loss. In addition, increased mobility of the primary teeth and stage of eruption of the neighbouring permanent teeth were recorded. The radiographic examination included measurements of the CEJ-MBL distance and the remaining root length. Also, exfoliating teeth, presence of proximal dentin caries, restorations and calculus were recorded from the radiographs. Associations between various explanatory variables and the CEJ-MBL distance were tested with both a chi 2 test and a variance components analysis. The mean CEJ-MBL distance for all primary tooth surfaces was 1.0 mm. Individual surfaces displayed distances ranging from 0.0-4.0 mm. Of the variables tested for association with the CEJ-MBL distance, eruption of neighbouring permanent tooth and exfoliation of neighbouring primary tooth seemed to be associated with large CEJ-MBL distances. When surfaces with these characteristics were excluded, a CEJ-MBL range of 0.0-2.0 mm was obtained.(ABSTRACT TRUNCATED AT 250 WORDS)


The effect of using a pre-brushing mouthwash (Plax) on oral hygiene in man. The aim of this study was to investigate whether the use of a pre-brushing mouthwash (Plax) improved subjects' oral hygiene over a 2-week period. In a double-blind placebo controlled cross-over study, 33 adult subjects (mean age 35.3 years) used either Plax or a placebo mouthwash for 30 s prior to toothbrushing during a 2-week period. After a washout period of 4 weeks, the subjects used the other mouthwash in the same way. The modified plaque index of Quigley and Hein (QHI) was recorded for 16 teeth (16, 14, 13, 11, 21, 23, 24, 26, 36, 34, 33, 31, 41, 43, 44, 46) at each visit. The bleeding index (BI) was recorded at the beginning and end of the study. Results were analysed using a paired one-tailed t-test. Neither plax nor placebo mouthwashes reduced plaque scores significantly (p > 0.05) below baseline. There was no statistically significant difference between the mean BI at the beginning of the trial (0.42) and at the end (0.44). These results suggest that the routine use of Plax is not a useful adjunct to toothbrushing.


Oral absolute bioavailability and intravenous dose-proportionality of cefprozil in humans. The absolute bioavailability (F) and dose proportionality of cefprozil were investigated in a parallel design study with an embedded two-way crossover leg. Twenty-four healthy male subjects divided into 3 dosing groups received a single 250-, 500-, or 1000-mg dose of cefprozil by a 30-minute intravenous infusion. Subjects assigned to the 500-mg dose group also received a 500-mg oral dose of cefprozil in crossover manner with a wash-out period of 7 days between each treatment. Cefprozil consists of cis and trans isomers in an approximate 90:10 ratio. Serial blood and urine samples were collected and analyzed for the concentrations of the cis and trans isomers of the cephalosporin using high-pressure liquid chromatographic assay with UV detection methods. After the 250-, 500-, and 1000-mg intravenous administration of cefprozil, the peak concentrations were 13.2, 26.0, and 48.5 micrograms/mL, and area under the plasma concentration versus time profiles were 17.2, 31.4, and 58.1 micrograms.hour/mL, respectively, for the cis isomer increasing in a dose proportional manner. Total body clearance, renal clearance, and volume of distribution at steady state, adjusted for body weight, were not significantly different among all groups. Mean residence time, elimination half-life, and urinary recovery were invariant with the dose. Based on the plasma and urine data, the estimates of F were 89% and 94% for the cis isomer, respectively. The plasma concentrations of the trans isomer were about 1/10th of the cis isomer, and all parameters were similar to those observed for the cis isomer. In summary, cefprozil exhibits linear pharmacokinetics and is essentially completely absorbed after oral administration.


Sustained antihypertensive activity of diltiazem SR: double-blind, placebo-controlled study with 24-hour ambulatory blood pressure monitoring. A new polymeric matrix technology provides a sustained-release formulation of diltiazem hydrochloride (diltiazem SR) suitable for once-daily therapy. The efficacy and safety of diltiazem SR were evaluated in a multicenter, randomized, double-blind, placebo-controlled, parallel-group study. After a single-blind, placebo lead-in period, 275 patients with mild to moderate essential hypertension were assigned to receive placebo or diltiazem SR 120, 240, 360, or 480 mg once daily for 4 weeks. The efficacy evaluation was based on office and 24-hour ambulatory blood pressure monitoring. Twenty-four hours after the last dose in the 4-week, double-blind treatment period, the mean reduction from baseline in supine diastolic blood pressure ranged from 5.1 to 10.6 mm Hg in the diltiazem SR 120- to 480-mg groups, resulting in a significant linear trend across all treatments (P less than .001). Reductions in systolic blood pressure were similar. Ambulatory blood pressure monitoring, performed in 138 patients, confirmed the dose-response relationship and showed consistent antihypertensive activity throughout the 24-hour dosing interval. The percentage of patients reporting adverse events was similar in the placebo- and active-treated groups. The results of this study indicate that diltiazem SR is well tolerated, lowers blood pressure in a dose-related manner, and provides sustained activity throughout the 24-hour dosing interval.


Circadian changes of valproate kinetics depending on meal condition in humans. The objective of this study was to examine the effect of meal condition on circadian changes in valproic acid (VPA) kinetics. Two experiments were performed in 16 healthy men that were synchronized with diurnal activity and nocturnal rest as their routine life. In both experiments, four 200-mg tablets of VPA were given orally on two occasions in the morning (8:30 AM) or in the evening (8:30 PM). In each study, a randomized, single-dose, two-way crossover design was used, and 2 weeks elapsed between morning and evening trials. In experiment 1, eight subjects took a light meal as breakfast between 8:00 and 8:15 AM and a heavy meal as dinner between 6:00 and 6:30 PM to fit the subject's usual food amount. The mean peak plasma concentration (Cmax) was significantly higher (P less than .01), the time to peak concentration (tmax) was shorter (P less than .05), and the absorption rate (Ka) was larger (P less than .05) after the morning dose than after the evening dose. In experiment 2, the size and contents of meal in breakfast and dinner were prepared in the same manner as the standard breakfast for the subjects. Namely, eight subjects took the same light meal between 8:00 and 8:15 AM in the morning and between 8:00 and 8:15 PM in the evening. There was no significant circadian change in VPA kinetics under this same meal condition. These results suggest that the differences of meal condition between morning and evening in our daily life play a major role in the mechanism underlying the circadian changes of VPA absorption in man.


Impact of food on the bioavailability of encainide. The bioavailability of drugs that undergo extensive presystemic hepatic metabolism may be increased by concomitant ingestion with food. The effect of food on the bioavailability of encainide, a class IC antiarrhythmic agent, was evaluated in 14 healthy subjects in this randomized crossover study. The subjects received encainide 35 mg every 8 hours for 7 days and were randomized to receive their test dose of encainide with food or after an overnight fast. Encainide area-under-the-concentration versus time curve (AUCs) were detectable in 3 of 14 subjects after fasting and in 7 of 14 after feeding. Although food increased the mean encainide AUC by more than threefold, this increase did not reach statistical significance because of the large number of subjects with indeterminate encainide AUCs. Food did significantly increase the AUC of O-demethyl-encainide (ODE), but not the AUC of methoxy-O-demethyl-encainide (MODE). Despite the increase in ODE AUC, no significant effect on the surface electrocardiogram 2 hours after dose administration could be detected. Food may increase the bioavailability of encainide and one of its active metabolites (ODE). The clinical relevance of this pharmacodynamic effect warrants further evaluation.


Chronopharmacology of furosemide in the elderly. The authors have previously reported the time-dependent change in the diuretic effects of furosemide, a loop diuretic agent, in young and middle-aged subjects. The current study was undertaken to examine an influence of aging on this chronopharmacologic phenomenon. Ten milligrams furosemide was given intravenously to 12 elderly subjects (greater than 70 years of age) at 9:00 AM (day trial) or at 9:00 PM (night trial) by a cross-over design. One-hour urine samples were collected for 3 hours after each administration, and urine volume and urinary excretions of sodium and furosemide were determined. Urine volume and urinary sodium excretion increased after furosemide administration. Contrary to the findings in the young and middle-aged subjects, no significant differences were observed in these parameters at any observation period between the day and night trials in the elderly subjects. Urinary furosemide excretion of the day and night trials did not significantly differ. These results suggest that the chronopharmacologic profiles of furosemide are altered in the elderly.


A new specific antibody reveals octopamine-like immunoreactivity in cockroach ventral nerve cord. An antiserum was raised in rabbits immunized with octopamine conjugated to thyroglobulin. The specificity of this antiserum for octopamine is shown by dot blot immunoassay analysis. The antiserum does not crossreact with dopamine, noradrenaline, and serotonin, but slight crossreactivity with the amine tyramine at high concentrations was observed. The tyramine crossreactivity could be eliminated by preabsorption with a tyramine-glutaraldehyde-BSA conjugate. Using this antiserum, we describe the topographical distribution of octopamine-immunoreactive (ir) neuronal elements in wholemounts and paraffin sections of the ventral nerve cord of the American cockroach. The pattern of octopamine immunostaining is completely different from that obtained with an antidopamine serum, and can be blocked by preabsorbing the antioctopamine serum with BSA-conjugated octopamine. Cell bodies and dendritic processes of putatively octopaminergic dorsal (DUM) and ventral (VUM) unpaired median neurons were clearly octopamine-ir in all ganglia examined. The numbers of stained DUM somata in the mesothoracic, metathoracic, and terminal ganglion of females correspond to those of peripherally projecting DUM cells revealed previously by retrograde tracing (Gregory, Philos Trans R Soc Lond [Biol] 306:191, 1984; Tanaka and Washio, Comp Biochem Physiol 91A:37, 1988; Stoya et al., Zool Jb Physiol 93:75, 1989). In addition, various, previously unknown, paired cells with octopamine-like immunoreactivity were found in all ventral ganglia except abdominal ganglia 3-6. Some of these probably project intersegmentally.


Functional degeneration of isolated central stumps of crayfish sensory axons. In the crayfish, Procambarus clarkii, nerve 5 carries primarily sensory axons from the tail fan to the 6th abdominal ganglion where they synaptically activate interneuron A. Since the sensory neurons have their somata located at the periphery, transection of nerve 5 part way to the ganglion allowed us to examine the fate of their soma-less central stumps. Up to 3 weeks postlesion the response to stimulation of nerve 5 consisted of a brief latency spike in interneuron A, similar to that in control animals and to stimulation of the intact nerve 4. Stimulation of the lesioned nerve 5 beyond 3 weeks failed to fire interneuron A. This loss of function was correlated to loss of axons in nerve 5 deduced by comparing the numbers in the lesioned nerve 5 to its contralateral intact counterpart. The numbers are about equal in the paired nerves but rapidly decline on the lesioned side to 50% within 1 week, 20% within 3 weeks, and less than 10% in subsequent weeks. This loss affects all size classes of axons. However, in the 3 week lesioned nerve large glial infoldings subdivided some of the larger axons and single nuclei were seen in a few of the medium-sized axons. Possibly subdivision of large axons by glial infolding may introduce glial nuclei into axons.


Distribution of the mRNA for a metabotropic glutamate receptor (mGluR1) in the central nervous system: an in situ hybridization study in adult and developing rat. Distribution of the mRNA for a metabotropic glutamate receptor (mGluR1), which is linked to phosphoinositide (PI) hydrolysis, was investigated in adult and developing rat central nervous system (CNS) by in situ hybridization. Transcripts of mGluR1 were specifically localized to neurons and widely distributed throughout the adult rat brain. Most intensely labeled neurons were Purkinje cells of the cerebellum, mitral and tufted cells of the olfactory bulb, and neurons in the hippocampus, lateral septum, thalamus, globus pallidus, entopeduncular nucleus, ventral pallidum, magnocellular preoptic nucleus, substantia nigra, and dorsal cochlear nucleus. Moderately labeled neurons were seen in high density in the dentate gyrus, striatum, islands of Calleja, superficial layers of the retrosplenial, cingulate and entorhinal cortices, mammillary nuclei, red nucleus, and superior colliculus. In the developing rat brain, the level of mGluR1 expression gradually increased during early postnatal days in accordance with the maturation of neuronal elements. These results show prominent expression of mGluR1 in the major targets of putative glutamatergic pathways and unique distribution pattern of mGluR1 distinct from those reported for ionotropic subtypes of glutamate receptors, suggesting specific roles of mGluR1 in the glutamatergic system.


Projections of leg proprioceptors within the CNS of the fly Phormia in relation to the generalized insect ganglion. We previously reported a modality-specific layering of leg sensory axons in the CNS of the flies Phormia regina and Drosophila melanogaster with tactile and gustatory axons projecting into a ventral layer and the proprioceptive hair plate axons into an intermediate layer. Here the description is expanded to include the afferent projections of campaniform sensilla on the legs and wings of Phormia. The leg campaniform sensilla produce a number of patterns of projections within an intermediate layer of their ganglion, some of which project intersegmentally into the other thoracic ganglia. One of these patterns is shared by the hair plate sense organs. Selected wing campaniform sensilla were also stained and showed that there is little or no overlap between the projections of leg and wing campaniform sensilla. Similarities with the arrangement of campaniform sensilla and their central processes in Drosophila melanogaster are discussed. To apply the results of this study to a broader range of insects we provide an atlas of the fly CNS and compare it with the locust, which has been the model for much insect neuroanatomy and neurophysiology.


Distribution of protein gene product 9.5 (PGP 9.5) in the vertebrate retina: evidence that immunoreactivity is restricted to mammalian horizontal and ganglion cells. Using light microscopic immunocytochemistry, we have studied the distribution of protein gene product 9.5 (PGP 9.5), a neuron-specific protein first extracted from human brain (Doran et al., '83:J. Neurochem. 40:1542-1547), in the vertebrate retina. Retinas were obtained from frog, chicken, rat, rabbit, cow, cat, dog, and human. No immunoreactivity was observed in frog and only a faint staining was present in chicken. In mammalian retinas, a strong positive reaction was restricted to horizontal and ganglion cells, with minor interspecies variations. Immunostaining was present throughout the cell body and the dendritic tree in horizontal cells. At the level of retinal ganglion cells, immunolabel was particularly abundant in cell bodies and axons forming the optic nerve. Only the main dendrites were stained, the remainder of the dendritic tree giving rise to a diffuse punctate reaction in the inner plexiform layer. In rats, displaced amacrine cells, which are known to contribute largely (40-50%) to the total neuronal population within the ganglion cell layer (Perry, '81: Neuroscience 6:931-944) were not immunoreactive, as demonstrated from (i) analysis of the morphology, cell size and cell density of immunoreactive neurons in wholemounts; (ii) colocalization of retrograde label and PGP 9.5 immunoreactivity in about 80% of ganglion cells after injection of peroxidase into the optic nerve; and (iii) reduction of immunoreactivity in the inner plexiform and ganglion cell layers following optic nerve transection. Western blot analysis of extracts from rabbit retinas indicated that the immunoreactive species is PGP 9.5 or a closely related molecule. Recent studies have demonstrated that PGP 9.5 is a ubiquitin carboxyl-terminal hydrolase (Wilkinson et al., '89:Science 246:670-673). The present results, therefore, suggest that differences in the ubiquitination process exist between retinal neurons.


Neurons in the cockroach nervous system reacting with antisera to the neuropeptide leucokinin I. Antisera were raised against the myotropic neuropeptide leucokinin I, originally isolated from head extracts of the cockroach Leucophaea maderae. Processes of leucokinin I immunoreactive (LKIR) neurons were distributed throughout the nervous system, but immunoreactive cell bodies were not found in all neuromeres. In the brain, about 160 LKIR cell bodies were distributed in the protocerebrum and optic lobes (no LKIR cell bodies were found in the deuto- and tritocerebrum). In the ventral ganglia, LKIR cell bodies were seen distributed as follows: eight (weakly immunoreactive) in the subesophageal ganglion; about six larger and bilateral clusters of 5 smaller in each of the three thoracic ganglia, and in each of the abdominal ganglia, two pairs of strongly immunoreactive cell bodies were resolved. Many of the LKIR neurons could be described in detail. In the optic lobes, immunoreactive neurons innervate the medulla and accessory medulla. In the brain, three pairs of bilateral LKIR neurons supply branches to distinct sets of nonglomerular neuropil, and two pairs of descending neurons connect the posterior protocerebrum to the antennal lobes and all the ventral ganglia. Other brain neurons innervate the central body, tritocerebrum, and nonglomerular neuropil in protocerebrum. LKIR neurons of the median and lateral neurosecretory cell groups send axons to the corpora cardiaca, frontal ganglion, and tritocerebrum. In the muscle layer of the foregut (crop), bi- and multipolar LKIR neurons with axons running to the retrocerebral complex were resolved. The LKIR neurons in the abdominal ganglia form efferent axons supplying the lateral cardiac nerves, spiracles, and the segmental perivisceral organs. The distribution of immunoreactivity indicates roles for leucokinins as neuromodulators or neurotransmitters in central interneurons arborizing in different portions of the brain, visual system, and ventral ganglia. Also, a function in circuits regulating feeding can be presumed. Furthermore, a role in regulation of heart and possibly respiration can be suggested, and probably leucokinins are released from corpora cardiaca as neurohormones. Leucokinins were isolated by their myotropic action on the Leucophaea hindgut, but no innervation of this portion of the gut could be demonstrated. The distribution of leucokinin immunoreactivity was compared to immunolabeling with antisera against vertebrate tachykinins and lysine vasopressin.


Localization of 3H-nicotine, 125I-kappa-bungarotoxin, and 125I-alpha-bungarotoxin binding to nicotinic sites in the chicken forebrain and midbrain. We have previously localized cholinergic cell bodies and fibers within the midbrain of the chicken with choline acetyltransferase immunohistochemistry. In a continuing effort to characterize the central cholinergic system, the present study examines the distribution of various nicotinic acetylcholine receptors in the forebrain and midbrain of the chicken. The binding of 3H-nicotine, 125I-kappa-bungarotoxin, and 125I-alpha-bungarotoxin was localized by film autoradiography in adjacent sections of the adult chicken brain, allowing a comparison of the distribution of different classes of nicotinic binding sites within the brain. Although all three ligands were often co-localized, there were areas that bound 3H-nicotine but not the 125I-neurotoxins, or vice versa. Very high densities of all three ligands were found in the hyperstriatum ventrale; the nucleus geniculatus lateralis, pars ventralis; the griseum tectale; the nucleus dorsolateralis anterior thalami; the nucleus lentiformis mesencephali, pars lateralis and pars medialis; the periventricular organ; and the stratum griseum et fibrosum superficiale, layer f of the optic tectum. The nucleus spiriformis lateralis had the highest levels of 3H-nicotine binding in the chicken brain, but it did not bind either of the two snake neurotoxins. On the other hand, high levels of both 125I-alpha-bungarotoxin and 125I-kappa-bungarotoxin binding were found in the nucleus semilunaris and the nucleus ovoidalis, but these areas contained little or no 3H-nicotine binding. No unique 125I-kappa-bungarotoxin sites, unrecognized by 125I-alpha-bungarotoxin, were identified by the low resolution autoradiography performed in this study. In general, nicotinic receptors were found in areas that have been reported to contain cholinergic cell bodies or fibers. Comparison of our results with the expression of neuronal nicotinic receptor subunits, as determined by in situ hybridization, suggests that many of the high affinity 3H-nicotine sites are localized presynaptically, as, for example, in the retinorecipient nuclei and the nucleus interpeduncularis. The lack of 125I-kappa-bungarotoxin binding in the presence of alpha-bungarotoxin indicates that the chicken brain has only very low levels of a unique kappa-bungarotoxin site. This is in marked contrast to chicken, frog, and rat autonomic ganglia, where a unique kappa-neurotoxin-sensitive receptor has been identified and shown to mediate nicotinic neurotransmission.


Novel developmental boundary in the cerebellum revealed by zebrin expression in the lurcher (Lc/+) mutant mouse. The cerebellar cortex contains at least two classes of Purkinje cells, which are organized into alternating arrays of parasagittal bands. The clearest demonstration of this compartmentation is the pattern of expression of a family of polypeptide antigens, the zebrins, which are expressed selectively by Purkinje cell subsets. Furthermore, anterograde tracing experiments show that the zebrin compartments are closely correlated with both afferent and efferent projection maps. The further subdivision of long parasagittal bands into smaller modules may occur through several different mechanisms, including the intrinsic cerebellar lobulation and the selective distribution of afferent terminal fields. However, while the longitudinal subdivisions are straightforwardly shown, the mediolateral boundaries are more subtle. In this report we describe a novel mediolateral and anteroposterior compartmentation boundary in mice, running across lobule VIII, that is revealed by the consequences of the lurcher (Lc/+) allele for zebrin expression. In normal mice zebrin compartmentation develops in several discrete stages: until postnatal day 5 (PD5) there is no zebrin expression; from PD5-PD7 zebrin is found only in the posterior lobe vermis, with immunoreactive Purkinje cells in lobules X, IX, and VIII but not elsewhere; from PD7-PD12 most Purkinje cells in the vermis become zebrin+; from PD12-PD15 immunoreactivity also appears in the hemispheres so that almost all Purkinje cells now are zebrin+; and finally, from PD15-PD25 zebrin is gradually suppressed in those Purkinje cells that are zebrin- in the adult until the mature pattern of parasagittal compartments is revealed. In the Lc/+ mutant the normal developmental progression is interrupted at around PD7. As a result, the pattern of zebrin expression becomes frozen at that stage when immunoreactive Purkinje cells are confined exclusively to the posterior lobe vermis. A reproducible boundary between expressing and nonexpressing zones runs mediolaterally across the dorsal surface of lobule VIII. Apart from zebrin expression itself, there are no obvious structural correlates of this transition. This mediolateral boundary identifies a developmental unit in the posterior lobe vermis of the cerebellum, and provides further evidence that the cerebellum is a highly heterogeneous structure.


Survival and integration of bovine chromaffin cells transplanted into rat central nervous system without exogenous trophic factors. Our previous studies have demonstrated that suspension grafts of isolated bovine chromaffin cells survive in the periaqueductal gray (PAG) of rat midbrain for up to 1 year after transplantation. The current study aimed to determine whether this type of graft could survive transplantation into sites other than the PAG that can benefit from chromaffin cell secretory products. In this study, electron microscope analysis showed that chromaffin cells implanted into the frontal neocortex, striatum, PAG, or the subarachnoid space overlying the spinal cord survived for at least 8 weeks without evidence of degeneration. Intraparenchymally placed grafts appeared relatively avascular and well integrated within the host parenchyma. When blood vessels were found, they were primarily at the host-graft border and were of the nonfenestrated central nervous system (CNS) type. Numerous synapses were present between the grafted cells and host neuronal processes. In addition, extensive intercommunication, via gap junction-like structures, was common in the grafts. Morphologic evidence of granular secretion was most commonly seen in striatal grafts. In contrast, subarachnoid grafts displayed minimal interaction with the host spinal tissue and were heavily vascularized with fenestrated capillaries. Despite morphologic differences between intra- and extraparenchymal grafts, this study demonstrates that isolated suspensions of bovine chromaffin cells survive transplantation into CNS sites without exogenous trophic factors and suggests that these cells are potential candidates for neural transplantation into these regions.


Rapid rearrangement of intrinsic tangential connections in the striate cortex of normal and dark-reared kittens: lack of exuberance beyond the second postnatal week. Clustered intrinsic connections in the kitten striate cortex originate from an unclustered, diffusely organized pattern prevailing during the first postnatal week. We have studied the progress of this reorganization and its dependence on visual input by determining the topographies of the intrinsic tangential connections at various postnatal ages by means of axonal tracing methods. Neurons were labeled either by diffusion of the carbocyanin dye DiI in animals ranging in age between 1 day and 30 days, or by retrograde transport of fluorescent microspheres in animals ranging in age between 7 days and 11 months. Quantitative evaluation of retrogradely labeled neurons revealed that during the first postnatal week, intrinsic tangential connections are organized in an unclustered fashion. During the second postnatal week a rapid rearrangement of connections occurs and is complete around postnatal day 11. The main events taking place during the course of this rearrangement are a decrease in the density of tangential connections and an arrangement of them in a clustered fashion. Once the clusters have been formed, the periodicity of the clustered pattern of connections and the size and distinctness of the clusters do not change. This means that the system of clustered tangential connections is adult-like at the end of the second postnatal week. Dark rearing affects neither the rapid rearrangement of horizontal connections into an adult-like system of clusters, nor the integrity of this clustered topography until the end of the first postnatal month. The overall distribution and the lateral extent of the tangential connections remain about the same during the postnatal period and are not affected by dark rearing until the end of the first postnatal month. We conclude that the clustered system of tangential connections in the cat's striate cortex is determined innately.


Müller cells in vascular and avascular retinae: a survey of seven mammals. Eight monoclonal antibodies were used to label Müller cells in four mammals that have vascular retinae (cats, dogs, humans, and rats) and in three with avascular retinae (echidnas, guinea pigs, and rabbits). Müller cells were found to have a fairly uniform retinal distribution in seven species, with a mean density of 8,000-13,000 cells mm-2. Müller cells in avascular retinae differ from their vascular counterparts in four respects. First, they are shorter than those in vascular retinae. This difference is mainly due to a reduction in the thickness of the outer nuclear layer. Second, the trunks of Müller cells in avascular retinae tend to be thicker, although those in echidnas are an exception to this trend. Third, Müller cell rootlets in avascular retinae follow a more tortuous course than those in vascular retinae, reflecting the fact that photoreceptor nuclei in the two types of retina have different shapes and stacking patterns. Fourth, due to a reduction in the density of photoreceptors in avascular retinae, there are fewer neurones per Müller cell. Although these four features may enable Müller cells to assist the nutrition of neurones in the inner layers of avascular retinae, they are unlikely to be morphological specializations that have evolved for that purpose. Rather, these features appear to be a direct consequence of the fact that avascular retinae are thinner and have a differently organised outer nuclear layer. These features aside, Müller cells in avascular retinae closely resemble their counterparts in vascular retinae.


Prenatal formation of the normal mouse corpus callosum: a quantitative study with carbocyanine dyes. Judgment of abnormalities in fetal cortical axon development is more sensitive when a good standard of normal ontogeny is established. The recent availability of postmortem tract tracing methods has greatly improved the observation of axon extension and growth cone morphology in mouse fetuses, which allows much stronger statements about the timing of crucial steps in the formation of the corpus callosum in particular. The first outgrowth and crossing of midplane by axons of the corpus callosum (CC) were examined in 153 normal mouse embryos and fetuses of the hybrid cross B6D2F2/J with carbocyanine dyes applied to brains fixed by perfusion. In most brains a crystal of DiI was inserted into either frontal, parietal, temporal, or occipital cortex in one hemisphere, and a crystal of DiA was placed into a different site in the opposite hemisphere. Although dye diffusion obscured the emergence of axons, linear regression analysis revealed that the first callosal axons emerged from their cortical cells of origin at about 0.4 g body weight or 15.5 days after conception for all four sites. Subsequent axon growth rate was substantially faster for those from frontal cortex (3.2 mm/day) than occipital cortex (1.8 mm/day). Axons from frontal cortex crossed the cerebral midplane first (0.69 g, E16.3), followed by those from parietal (0.74 g), temporal (0.77 g) and occipital cortex (0.92 g, E16.9). Prior to crossing midplane, the pioneering CC axons were usually 200 microns or less in advance of the main bundle, but when they crossed midplane and encountered CC axons growing from homotopic sites in the opposite hemisphere, the pioneering axons were often 0.5 to 2.5 mm ahead of the main bundle. Growth cones were usually large and complex until they had crossed midplane and were thereafter smaller with simple and flat morphologies. The topography of axons in the CC at midplane was organized according to cortical region of origin from the very beginning, when the CC was only a small cap over the hippocampal commissure and dorsal septum. The quantitative results provide a convenient standard for normal callosal development in mice and should facilitate comparative studies.


Distribution of corticotropin-releasing factor-like immunoreactivity in squirrel monkey (Saimiri sciureus) amygdala. Previous anatomical studies of corticotropin-releasing factor (CRF)-like immunoreactivity in rat brain have reported prominent clustering of neuronal elements containing this peptide within the amygdala. The highest concentrations of both CRF-positive cells and fibers were evident in the central nucleus, an observation consistent with the putative role of this peptide in autonomic and endocrine regulation. In addition, lower densities of CRF-positive somata and processes have been noted in other amygdaloid nuclei. However, the distribution of CRF-like immunoreactivity in the amygdala has not been described for any primate species. Such a description would be of interest since substantial differences in the distribution of CRF in rodent and primate have been reported for other brain regions. The present study uses immunohistochemical methods, with a polyclonal antiserum directed against the human form of CRF, to determine the distribution of this peptide in non-colchicine-treated monkeys (Saimiri sciureus). Within the amygdaloid complex, the most numerous and concentrated collections of CRF-positive neurons were seen in the basal and lateral nuclei. The highest densities of CRF-positive fibers and terminals were seen in the lateral and central amygdaloid nuclei. Moderately dense plexuses of CRF-positive fibers also were seen in layer Ia of the periamygdaloid cortex, nucleus of the lateral olfactory tract, anterior and posterior cortical nuclei, and the medial nucleus. Thus, the distribution of CRF-like immunoreactivity differs substantially in monkey and rat amygdala. Since CRF-positive perikarya in monkey are most prominent in nuclei with pronounced interconnections with neocortex, these differences may be an integral component of the increased cortical development that characterizes the primate brain.


Lucifer yellow, retrograde tracers, and fractal analysis characterise adult ferret retinal ganglion cells. The dendritic morphology of retinal ganglion cells in the ferret was studied by the intracellular injection of lucifer yellow in fixed tissue. Ganglion cells were identified by the retrograde transport of red or green fluorescent microspheres that had been injected into different target nuclei, usually the lateral geniculate nucleus or superior colliculus. This approach allows the comparison of dendritic morphologies of ganglion cells in the same retina with different central projections and also identifies cells with branching axons. The digitised images of dendritic arbors were analysed quantitatively by a variety of measures. Dendritic complexity was assessed by calculating the fractal dimension of each arbor. The ferret has distinct alpha, beta, and gamma morphological classes of cells similar to those found in the cat. The gamma cell class was morphologically diverse and could be subdivided into "sparse," "loose," and "tight" groups, reflecting increasing dendritic complexity. Whereas the beta cell projection was limited to the lateral geniculate nucleus alone, alpha and gamma cells could project to either or both nuclei. Retinal ganglion cells labelled from the pretectal nuclei formed a morphologically distinct class of retinal ganglion cells. The ipsilateral projection lacked alpha cells and the most complex, "tight" gamma cells. However, ipsilaterally projecting "loose" gamma cells overlapped alpha cells in both soma and dendritic dimensions. Different morphological classes of retinal ganglion cells hence show characteristic axon behaviour both in their decussation at the chiasm and in which targets they innervate. Fractal measures were used to contrast variation within and between these identified classes.


The shell region of the nucleus ovoidalis: a subdivision of the avian auditory thalamus. The connectivity of a region surrounding the established thalamic auditory nuclei, n. ovoidalis (Ov) and n. semilunaris parovoidalis (SPO), was explored in the ring dove by using the anterograde tracers, Phaseolus vulgaris leucoagglutinin (PHAL) and biocytin, and the retrograde tracer, fluorogold. The Ov-SPO surround received a projection from a cell group along the interface of the auditory midbrain and the n. intercollicularis, as revealed with PHAL and biocytin, and was composed of neurons exhibiting a common morphology. These features and the presence of overlapping projections from different portions of the Ov-SPO surround suggest that this region comprises a functionally discrete area, which we term the Ov shell. Single unit recording within the shell established the existence of acoustically responsive units. Both PHAL and fluorogold labeling revealed a robust projection from the Ov shell to the caudomedial hypothalamus. Major telencephalic projections of the shell terminated within the ventral paleostriatal complex, "end-zones" of the field L, the caudomedial hyperstriatum ventrale, and regions immediately dorsal and lateral to the auditory neostriatum. Except for a portion of the shell bordering medial ovoidalis, PHAL injections into the shell also labeled fibers within the caudolateral neostriatum and along the lateral neostriatal rim. The connectivity of the Ov shell suggests that this region may integrate auditory pathways with brain regions associated with endocrine mediated behavior. In addition, the shell may constitute a source of converging input to several levels of central auditory pathways.


Development of the olivocerebellar projection in the rat: I. Transient biochemical compartmentation of the inferior olive. In the present study the early phases of the development of the inferior olive were examined by using immunocytochemical techniques. We observed that, from embryonic day 16 onward, antibodies against the calcium binding proteins parvalbumin and calbindin and the calcitonin gene related peptide stain partially overlapping territories of the inferior olive. This staining delimits a biochemical zonation of the inferior olive which is combinatory and transient. We have previously observed a biochemical parcellation of the cerebellar Purkinje cells which, like that of the inferior olive, is first observed at E16, involves the combined expression of marker proteins and is also transient. In order to know whether the biochemical compartmentations of the cerebellum and inferior olive arise independently, the time course of the development of the olivocerebellar projection was studied by anterograde and retrograde in vitro axonal tracing by using the fluorescent carbocyanine dye DiI. The olivocerebellar axons were found to reach the limit of the cerebellar plate at E16 and to enter it at E17. Even at this age the great majority of the climbing fibers are tightly fasciculated, which minimizes their interactions with the PC clusters. These observations indicate that the topographical heterogeneity of Purkinje cells and inferior olive neurons arise independently. The transient biochemical individualization of subgroups of neurons during development could contribute to recognition mechanisms.


Development of the olivocerebellar projection in the rat: II. Matching of the developmental compartmentations of the cerebellum and inferior olive through the projection map. A transient biochemical parcellation has been observed by immunocytochemical methods, during the perinatal development of both the inferior olive and the cerebellum. In the present study, we sought a relationship between this developmental compartmentation and the organization of the olivocerebellar projection. In the inferior olive, a transient parvalbumin immunoreactivity restricted to the dorsal cap of the medial accessory olive is observed around birth. The climbing fiber projection of the dorsal cap was identified in the cerebellum of newborn rats based on its parvalbumin immunoreactivity. The pattern of this projection, restricted to lobules IX and X of the vermis, and to the flocculus, is indistinguishable from that of the adult medial accessory olive, which was previously described from axonal tracing experiments. The parvalbumin immunoreactive climbing fibers were followed between birth and postnatal day 7. In the caudal vermis, Purkinje cell subpopulations can be identified between embryonic day 20 and postnatal day three, on the basis of their differential immunostaining with an antibody directed against a specific peptide, PEP 19. In lobule X, the parvalbumin immunoreactive climbing fibers form two sagittal bands on each side of the midline, one medial and one lateral. The medial parvalbumin immunoreactive climbing fiber band is coextensive with a PEP 19 negative Purkinje cell cluster, indicating a clear relationship between the biochemical parcellations of the cerebellum and inferior olive.


Myelin-axon relationships in the rat phrenic nerve: longitudinal variation and lateral asymmetry. It is known that the myelin sheath thickness-axon perimeter relationship varies between peripheral nerves. This study examines the possibility that that relationship may vary between levels along a given nerve or between corresponding levels of the right and left examples of the same nerve. The relationship is examined for large and small fibre classes at well separated upper and lower intrathoracic levels in the rat phrenic nerve. The study shows that the myelin-axon relationship differs between levels along the same nerve bundle in the same (intrathoracic) environment. Thus, for a given increase in the perimeter of large axons, sheath thickness increases significantly more at lower than at upper levels. In addition, myelin sheath thickness shows a statistically significant lateral asymmetry in favour of the left side for the large fibre class at the upper thoracic level. The setting of the myelin sheath thickness-axon perimeter relationship also differs between the large and small fibre classes at each level examined. Large fibres have proportionately thicker sheaths than small fibres and this difference is reflected in the significantly smaller g-ratio of the former. Systematic differences in the setting of the myelin sheath thickness-axon perimeter relationship between large and small fibre classes may be a widely occurring phenomenon. It may be concluded that the myelin-axon relationship varies significantly both within and between nerves and also between fibre classes. Accordingly, morphometric studies of normal or pathological nerves should take into account possible consistent longitudinal variation or lateral asymmetry in fibre parameters and myelin-axon relationships within a given nerve bundle or fibre class, in order to avoid introducing systematic bias and to minimize variance between samples.


Time of origin of cortico-collicular projection neurons in the rat visual cortex. The time of origin and the radial gradient of neurogenesis of cortico-collicular neurons have been studied in the rat visual area 17. We used a combined technique for the histochemical detection of the retrogradely transported horseradish peroxidase from the superior colliculus and the autoradiographic detection of the [3H]-thymidine administered during the gestational period. The cortico-collicular neurons of visual area 17 are located in layer V and are generated on gestational day (GD) 15 (59.78%), GD 16 (36.21%), and GD 17 (4.01%). This finding reveals that, for the cortico-collicular neuronal population, the birth date is well-correlated with the laminar position in the adult animal. To see whether the cortico-collicular neurons located at various radial levels of layer V are generated concurrently, or whether they follow an "inside-out" pattern of positioning, we divided layer V into three (upper, middle and lower) sublaminae. Most cortico-collicular neurons located in the lower two-thirds of layer V are generated on GD 15 (65%), whereas the neurons located in the upper third of the layer are generated both on GD 15 and GD 16 in almost equal proportions (52.53% and 44.39%, respectively).


Effects of sex and androgen treatment on dendritic dimensions of neurons in the sexually dimorphic preoptic/anterior hypothalamic area of male and female ferrets. A sexually dimorphic group of cells at the dorsal border of the preoptic/anterior hypothalamic area (POA/AH) of ferrets has been previously identified in Nissl-stained tissue. In this study, Golgi-stained tissue was examined in order 1) to determine whether sex differences exist in dendritic dimensions of neurons from this region, and 2) to assess the effects of adult androgen treatment on dendritic morphology in ferrets of both sexes. Brains from adult ferrets given daily injections of testosterone propionate (5 mg/kg body weight) or oil vehicle for 5 weeks after gonadectomy were impregnated by Golgi-Cox procedures. After sectioning at 120 microns, 78 multipolar neurons were selected from the sexually dimorphic POA/AH of 12 ferrets and reconstructed in three dimensions with the aid of a computer-assisted neuron tracing system. Large sex differences were observed in somal area and most aspects of dendritic morphology, including total length, number of branches, and total dendritic surface area. Androgen also appeared to accentuate dendritic arborization in both sexes, but this effect was weaker than the sex effect, more apparent in males than females, and restricted to fewer variables. The most statistically significant effects of adult androgen treatment in males were found for total dendritic surface area and percentage of fourth order dendrites, and in females, average dendritic thickness. These data show that strong sex differences exist in dendritic structure of neurons in the POA/AH, and suggest that alterations in levels of gonadal steroids in adulthood may promote synaptic remodeling in a region of the brain involved in the control of sexually dimorphic behaviors.


Projections from the lateral nucleus to the basal nucleus of the amygdala: a light and electron microscopic PHA-L study in the rat. A recent study, carried out in the monkey brain demonstrated a hitherto undescribed projection from the lateral to the basal nucleus of the amygdaloid complex. In the present study, we used light and electron microscopic techniques to determine whether a similar connection exists in the rat brain and to define what type(s) of synaptic contacts are produced by fibers of this projection. Injections of the lectin tracer Phaseolus vulgaris leucoagglutinin (PHA-L) were placed into several levels of the lateral nucleus and the distribution of fibers in the basal (basolateral) nucleus was evaluated. All lateral nucleus injections resulted in labeled fibers in the basal nucleus, though the density and distribution of labeled fibers depended on the position of the injection site within the lateral nucleus. In general, the heaviest labeling of the basal nucleus was observed after injections at midrostrocaudal levels of the lateral nucleus, especially when the injection was located ventrally. Fibers originating from cells labeled by these injections were observed throughout much of the rostrocaudal extent of the basal nucleus. Rostrally situated injections resulted in substantially lower levels of labeled fibers in the basal nucleus. Injections placed caudally in the lateral nucleus resulted in light to medium levels of labeled fibers in the basal nucleus; the terminal field in these cases did not extend as far rostrally as after the rostral and midlevel injections. Electron microscopic analysis of PHA-L labeled fibers revealed that they contributed synapses to the basal nucleus. The majority of PHA-L labeled terminals formed asymmetric contacts on dendritic spines or shafts; a smaller number of PHA-L labeled terminals formed symmetrical synapses.


Photic regulation of Fos-like immunoreactivity in the suprachiasmatic nucleus of the mouse. In mammals, the suprachiasmatic nucleus (SCN) of the hypothalamus functions as the primary pacemaker of the circadian system. Light has been shown to induce Fos-like immunoreactivity (Fos-LI) in the SCN of rats and hamsters. The purpose of the present study was to evaluate extensively the effect of light on Fos-LI in the mouse SCN. Brief pulses of light administered to animals otherwise in constant darkness were found to induce Fos-LI. This photic induction was unaffected by the rd mutation, which causes the profound loss of photoreceptors but fails to affect circadian responses to light. Light regulation of Fos-LI was dependent upon the phase of the circadian cycle in which the light pulse was administered. Phases at which light causes phase shifts of the circadian system were permissive for Fos-LI induction (CT 16 and 24), while phases in which light does not cause phase shifts were not permissive (CT 6 and 9). The time course of the induction at CT 16 was also described. In a light/dark cycle, Fos-LI was found to be rhythmically expressed with Fos-LI elevated soon after the lights came on but remaining low throughout the rest of the cycle. However, this rhythm is a direct consequence of the light because in constant darkness Fos-LI was always low. These results have implications regarding the possible functional roles of Fos in the circadian system and add to our understanding of light regulation of circadian physiology in the mouse.