Psychological interventions with AIDS and HIV: prevention and treatment. In the decade since acquired immune deficiency syndrome (AIDS) was first diagnosed, behavioral research has focused intensively on risk reduction change processes and, to a lesser extent, on mental health needs of persons with human immunodeficiency virus (HIV) conditions. Although research to date has yielded important findings for primary prevention efforts and has identified some psychological dimensions relevant to mental health interventions, there is a pressing need for much more systematic intervention outcome research in both the prevention/behavior change and emotional coping areas. Progress in these areas will be facilitated by better linkage of intervention approaches to behavioral theory; identification of intervention elements that produce HIV risk behavior change; evaluated field-testing of promising intervention models; continued focus on populations that remain at risk (such as gay men and injection drug users); and expansion of prevention efforts to urban, poor, and minority populations increasingly threatened as AIDS/HIV enters a "second wave." Although AIDS is still a relatively new problem, existing behavioral medicine conceptual models and intervention strategies can be adapted to meet the enormous challenges created by AIDS and HIV infection.


Recent advances in the assessment and treatment of insomnia. Persistent insomnia has multiple potential causes such as medical, pharmacological, life-style, personality, and behavioral factors. Although many poor sleepers use hypnotic medications, a wide array of cognitive-behavioral interventions are available that target somatic and cognitive arousal, dysfunctional thoughts, and learned maladaptive sleep habits. Outcome research conducted over the past decade reveals that the single treatments of stimulus control and sleep restriction produced the best results, reducing self-reported target complaints by 50-60%. Approximately half of insomniacs show reliable change although only about one third become good sleepers. Multicomponent methods offer considerable promise but on the whole have not surpassed results achieved with the simpler stimulus control. Recommended new directions of pursuit include (a) examination of a broader range of insomnia sufferers, (b) use of multimodal assessment and more objective verification of self-reported benefits (c) research on treatments tailored to individual causal and maintaining factors, and (d) further scrutiny of newer interventions like sleep restriction and more comprehensive multifaceted strategies.


Type A behavior pattern: new perspectives on theory, assessment, and intervention. Research on the Type A behavior pattern (TA) has been plagued by inadequate theory, insensitive assessment, and insufficient interventions. These problems (e.g., using global dichotomous ratings of TA) have contributed to several failures of TA to predict cardiovascular outcomes prompting concern for new approaches. Conceptual models are discussed, such as a transactional model of TA, social cognitive theories (e.g., self-evaluative processes), and associative network theory (e.g., how emotions distort information). The view of hostility as the only pathogenic feature of TA is questioned. The ethnographic gap in TA research is described, and detailed descriptive and experimental case studies are recommended. Profile measures that assess all dimensions of TA are urged along with contextually sensitive multimodal assessments. Unlike results of some correlational studies, controlled TA interventions, although few, have consistently yielded positive results. Study of TA within an expanded conceptual perspective is encouraged, especially controlled experiments and interventions.


Behavioral medicine approaches to gastrointestinal disorders. Behavioral research in gastroenterology has grown exponentially over the last decade. Controlled studies demonstrate that psychotherapy, stress management, and hypnosis are effective for irritable bowel syndrome; and behavioral treatments are preferred over medical management for some types of fecal incontinence and vomiting. For peptic ulcer disease, interest in behavioral treatments has declined. However, a new syndrome, functional dyspepsia, is now recognized, in which ulcerlike symptoms occur without ulcer and frequently in association with psychological symptoms. For inflammatory bowel disease, stress management training has produced inconsistent outcomes. Newly recognized disorders for which behavioral treatments are needed include constipation associated with inability to relax the pelvic floor muscles during defecation, functional rectal pain (proctalgia), noncardiac chest pain, and aerophagia (excessive air swallowing).


Exercise in behavioral medicine.

Exercise in behavioral medicine. Research on the preventive and rehabilitative applications of exercise and literature on exercise adherence from the past 10 years are briefly reviewed. Although there is now substantial evidence that a low level of physical activity is associated with decreased life expectancy for both men and women and contributes independently to the development of many prevalent chronic diseases, most adults and children lead sedentary lives. Recent intervention studies suggest exercise adherence can be improved in a variety of populations. Researchers in the next decade should continue to elaborate the population- and disease-specific effects of physical activity and exercise and give priority to the problem of exercise adherence, which limits the effectiveness of exercise interventions and remains a significant challenge to behavioral medicine.


Psychological factors in rheumatoid arthritis. This article provides a review and discussion of recent developments in psychological research related to rheumatoid arthritis (RA). A description of the medical aspects of the disease is followed by an overview of the literature relating psychological variables to pain and disability in RA; a summary evaluating affective reactions, disease-related beliefs, and coping strategies in RA patients; and a discussion of psychological interventions with this patient population. Methodological weaknesses in the literature are noted and directions for future collaborative research between rheumatologists and psychologists are suggested.


Major developments in behavioral diabetes research. Over the past decade, there has been a major increase in behavioral diabetes research. This review focuses on 6 areas: self-treatment, psychosocial impact, diabetes-specific assessment, psychological stress, weight loss intervention, and neuropsychological effects. There has been great progress in identifying factors that predict self-treatment behaviors and psychological adjustment. This research has produced a number of diabetes-specific assessment tools. Psychological stress appears to affect both the etiology and the control of diabetes, but underlying mechanisms remain unclear. Weight loss studies demonstrate the potential benefits of behavioral interventions for diabetes management. Both acute and chronic abnormalities in diabetic blood glucose cause neuropsychological impairments and may cause permanent deficits. The challenge for the next decade is to translate these findings into interventions that improve quality of life and physical well-being for individuals with diabetes.


Psychological approaches to the treatment of asthma. Outcome literature on psychological treatment for asthma covers psychoeducational self-management programs, relaxation therapy, biofeedback, and family therapy. Psychoeducational approaches now being standardized in a national program are cost-effective. They produce improved adjustment, increased medication compliance, greater perceived self-competence in managing symptoms, and decreased use of medical services. Significant effects have been found for relaxation therapy, although it is not clear whether the effectiveness depends on whole-body relaxation or specifically facial- or respiratory-muscle relaxation. Family therapy is helpful to some asthmatics. Active components in these methods remain to be identified as do the populations whom they can best serve. Biofeedback for respiratory resistance, trachea sounds, and vagal tone shows promise but has not been given adequate clinical testing.


Axon populations in cat lingual and chorda tympani nerves. The lingual and chorda tympani nerves from five cats were examined so that normal axonal populations could be determined. After perfusion fixation, the chorda tympani and lingual nerves were removed and processed, and sections were taken from individual and combined nerves for both light and electron microscopy. The chorda tympani remained as a distinct group of smaller axons for at least 4 mm distal to its junction with the lingual nerve. The mean number +/- S.D. of myelinated axons in the chorda tympani central to the junction was 1322 (+/- 268) and in the lingual nerve central to the junction, 3227 (+/- 510). The counts were not significantly different distal to the junction, and there were no side-to-side differences. Mean myelinated axon circumferences were significantly smaller in the chorda tympani (12.86 +/- 0.87) than in the lingual nerve (22.79 +/- 1.99; p less than 0.01). The mean size of axons in the chorda tympani was slightly but consistently larger on the left (13.1 +/- 0.73) than on the right side (12.61 +/- 1.01; p less than 0.05). Distal to the junction, the average proportion of non-myelinated axons was 44% in both chorda tympani and lingual nerves.


Effect of calcium in model plaque on the anticaries activity of fluoride in vitro. The uptake of calcium by a polysaccharide (agarose) gel used as a model for plaque from a two-step treatment (consisting of a calcium rinse followed by a fluoride treatment) and the effect of the deposited calcium in model plaque on caries lesion formation in enamel were determined. Calcium uptake was measured by treatment of the model plaques with [45Ca]-CaCl2 solutions with or without NaF. A two-step treatment consisting of calcium followed by fluoride produced a 100% increase in calcium content of model plaque, presumably due to the formation of CaF2, compared with a treatment with artificial saliva followed by calcium alone. The effects of these increased plaque minerals on caries lesion formation were studied by subjecting model-plaque-covered enamel blocks to a cyclic demineralization-remineralization treatment. Artificial-plaque-covered enamel blocks were treated daily with 180 ppm calcium for ten min, then 100 ppm fluoride for ten min, followed by demineralization for 16 h, and finally, remineralization for seven h and 40 min. After five days, the blocks were sectioned, and lesion formation was determined by microradiography-microdensitometry. Artificial plaque treated with a calcium rinse followed by a fluoride rinse reduced lesion size by 90%, compared with a 68% reduction by a fluoride rinse alone. When the experiment was repeated with a simulated pre-brush calcium rinse (180 ppm calcium) followed by a fluoride dentifrice suspension (110 ppm fluoride), lesion size was reduced by 46%, compared with a 32% reduction by the fluoride dentifrice suspension alone.


Effect of age on the rate of tooth movement in combination with local use of 1,25(OH)2D3 and mechanical force in the rat. The purpose of this study was to compare the amount and rate of tooth movement in young and mature rats administered 1,25(OH)2D3 simultaneous with application of mechanical force. In 30 seven-week-old and 30 28-week-old male Wistar rats, the right maxillary first molar was moved buccally with a fixed appliance. The appliances delivered forces ranging from 5 to 20 g. Twenty microL of 1,25(OH)2D3 (10(-10) and 10(-8) mol/L) was injected locally into the submucosal palatal area of the root bifurcation of the right first molar. The left side was injected with phosphate-buffered saline (PBS). In young rats receiving 10(-10) mol/L 1,25(OH)2D3 every three days, tooth movement significantly increased to 126% of that in PBS-injected control rats on day 20. In 1,25(OH)2D3-injected mature rats, tooth movement was stimulated markedly and increased with 10(-10) mol/L to 245% and with 10(-8) mol/L to 154% of the amount of tooth movement seen in the PBS-injected controls by the end of the experiment. PBS-injected rats had a plateau stage where tooth movement did not occur at all, while there was no such lag-time in the 1,25(OH)2D3-injected group which showed continuous tooth movement. The local injection of 1,25(OH)2D3 did not change serum calcium, phosphate, and alkaline phosphatase activity, and there were no apparent clinical or microscopic side-effects.


Solubilization of dentin matrix collagen in situ. The effects of the oral environment on dentin matrix collagen were studied. In the partial prostheses of 12 participants, two completely demineralized dentin specimens were mounted covered by a Dacron gauze. After an experimental period of seven weeks, the specimens were transferred to a trypsin-containing buffer for determination of the amount of denatured collagen. Subsequently, the specimens were incubated with a bacterial collagenase for assessment of the amount of collagen. After the intra-oral exposure, there was a collagen loss varying between 1 and 47 wt%. This variation might be due to differences in proteolytic activity of the colonizing microflora. After exposure to the oral environment, only about 0.5 wt% of the available collagen was trypsin-degradable. This indicates a rapid solubilization of the denatured collagen from the specimens into the oral cavity. A separate group of specimens was examined by light microscopy and transmission electron microscopy. Various degrees of breakdown could be discerned. Some experimental specimens showed loss of surface integrity and tubules heavily infected with different types of micro-organisms. The lumens of the tubules were enlarged, sometimes creating caverns as a result of the loss of the intertubular collagenous matrix.


Determination and selection of the optimum number of sites and patients for clinical studies. Calculating required sample sizes is a critical step in the design of any study. For dental studies, the sample size needs to be specified at two levels: (1) the number of patients (n) enrolled in the study, and (2) the average number of sites (m) examined per patient. In general, m and n should be selected in such a way that the precision of the research findings is maximized, while the cost of the study is minimized. This objective can be realized by taking stock of the components of variation and the costs involved with enrolling patients and examining sites. The research cost for n patients ($C1/patient), at an average of m sites per patient ($C2/site), can usually be approximated by nC1 + nmC2. The precision varies as a function of the variance components, m, and n. To optimize precision for a fixed cost, the average number of sites examined per patient (m(opt)) should be approximately equal to [formula: see text] where rho is the within-patient correlation coefficient of the site-specific variable measured. When m(opt) is approximately equal to or in excess of the average number of sites available per patient, whole-mouth examinations are indicated. When m(opt) is considerably smaller than the average number of sites available, the sample of optimum size should be obtained by some random mechanism. Examination of a number of sites considerably different from m(opt) results in a waste of resources, regardless of the number of patients studied. Standard statistical analyses for determination of the patient sample size required to obtain a pre-specified precision or power are discussed.


Chewing pressure vs. wear of composites and opposing enamel cusps. The effects of various chewing pressures on the wear of composites and enamel were assessed in vitro. Standardized composite discs (8 mm in diameter, 2 mm in height) were made of a fine-particle hybrid (FPH), a coarse-particle hybrid (CPH), and a homogeneous microfilled composite (HMC). The composite specimens were chemically degraded by immersion in 75% ethanol for 24 h, brushed for 30 min, and then thermocycled 300 times (5-55-5 degrees C) while being occlusally loaded 120,000 times at 1.7 Hz, with chewing forces of 25, 50, 75, and 100 N. Standardized human enamel cusps with a uniform contact area of 0.384 mm2 served as antagonists in the chewing machine. Wear of the composites and enamel cusps, their combined wear, and the increase of the enamel contact surfaces were quantified. An increase in chewing pressure significantly enhanced the wear of both composite and enamel in all groups except for the antagonists opposing a HMC. The FPH was most wear-resistant to in vitro chewing pressures in the range of 6.58 to 19.74 MN/m2, the CPH at 26.32 MN/m2, while the HMC was the most enamel-friendly of the three composites tested. The FPH composite had the least disintegration in the occlusal contact area. The ranking of the composites generally varied at the different chewing pressures with respect to the three types of quantified wear--that is, composite wear, enamel wear, and total wear.


Morphological aspects of the resin-dentin interdiffusion zone with different dentin adhesive systems. Cross-sections of resin-dentin interfaces were etched with an argon-ion beam to make their substructure detectable by scanning electron microscopy. The dentin adhesive systems were categorized morphologically into three groups, and an attempt was made to clarify their adhesive mechanism. The first group of products removed the smear layer. The argon-ion bombardment clearly disclosed a hybrid or resin-impregnated dentin layer. It is hypothesized that conditioning with acidic or chelating agents demineralized the dentin surface-layer to a certain depth, leaving behind a collagen-rich mesh-work. Hydrophilic monomers are then believed to alter this collagen-fiber arrangement in a way that facilitates penetration of the adhesive resin, resulting in a mechanical, intermingled link between collagen and the adhesive resin. The second group preserved the smear layer. In this case, the dentinal tubules were obliterated with globular particles at their orifices and remained patent underneath these smear plugs. This type of adhesive system aims at the incorporation of the smear layer into the hydrophilic monomers, which have an affinity for the organic and/or inorganic components of the underlying dentin. Finally, a third, small group only partly dissolved the smear layer, creating a thin resin-impregnated dentin layer and a resin-impregnated smear plug. This study clearly showed that the application of recent adhesive systems induced structural changes in the dentin surface morphology, creating a retentive interface, called the inter-diffusion zone, between the deep, untouched dentin layers and the composite filling material. This resin-dentin interdiffusion zone offers bonding sites for copolymerization with the resin composite and, concurrently, might have protective potential for the pulp tissues.


Characterization of external ear impulse responses using Golay codes. This report explains the use of a complementary series, Golay codes, for probing the impulse response of the external ear. The codes are used to measure both the resonance of the human ear canal, using a sealed sound-delivery system, and to measure the transfer function of the pinna, using a free-field source. With two series of 512 binary numbers, the improvement in signal-to-noise ratio over a single impulse approaches the theoretical value of 30.1 dB [10 log(2.512)]. This technique has many of the same properties as maximal-length sequences [M. R. Schroeder, J. Acoust. Soc. Am. 66, 497-500 (1979)], but it has the added advantage that the sequence length is an integer power of two and is, therefore, particularly convenient to use with modern Fourier transform techniques.


Lack of association between otoacoustic emissions and hearing difficulty in subjects with normal hearing thresholds. Evoked otoacoustic emissions (EOAE) are a sensitive indicator of subtle cochlear damage and hence might explain why some people complain of excessive difficulty understanding speech in a background of noise, despite having normal hearing thresholds. This phenomenon has been termed "Obscure Auditory Dysfunction" (OAD). Recorded EOAE waveforms from a group of 50 OAD patients were compared with those from a group of 50 matched controls. No significant difference could be found between the two groups across a range of objective and subjective descriptors of the EOAEs. Any cochlear component of OAD does not appear to affect the function of the outer hair cells sufficiently to modify EOAEs materially.


Ultrasonic attenuation in articular cartilage. Previous studies have utilized articular cartilage from joints as a model to investigate the influence of various constituents in a connective tissue matrix on ultrasonic properties. These studies have assumed a degree of homogeneity of articular cartilage taken from the same joint. However, tactile loads on articular cartilage vary significantly with location in a joint, and the effects of mechanical load on the connective tissue matrix and the resulting effects on ultrasonic properties are not known. This work reports the variations in acoustical properties of bovine articular cartilage from the stifle (knee) joint both among different joints and within each joint. A pulse-echo transmission technique was used to measure acoustic attenuation in the frequency range of 10 to 40 MHz. The attenuation coefficient was characterized by the integrated attenuation (mean value) over the frequency bandwidth considered. Integrated attenuation averaged over each joint varied among joints from 3.2 to 7.5 NP/cm (6.0 +/- 2.0, mean +/- s.d.). Additionally, a linear regression (r = 0.59) of all the data versus location along the patellar groove indicated that within joints integrated attenuation increased from proximal to distal locations by 6% to 60% (32 +/- 25, mean +/- s.d.). The variations observed among joints and along the patellar groove within a given joint suggest that studies utilizing articular cartilage to determine the role of connective tissue constituents on acoustic properties require control for joint and location. An additional outcome of this study was the observation that damage to the load-bearing surface of articular cartilage may be detectable ultrasonically through characteristics of the acoustic reflection from the articular surface.


Inferring articulation and recognizing gestures from acoustics with a neural network trained on x-ray microbeam data. This paper describes a method for inferring articulatory parameters from acoustics with a neural network trained on paired acoustic and articulatory data. An x-ray microbeam recorded the vertical movements of the lower lip, tongue tip, and tongue dorsum of three speakers saying the English stop consonants in repeated Ce syllables. A neural network was then trained to map from simultaneously recorded acoustic data to the articulatory data. To evaluate learning, acoustics from the training set were passed through the neural network. To evaluate generalization, acoustics from speakers or consonants excluded from the training set were passed through the network. The articulatory trajectories thus inferred were a good fit to the actual movements in both the learning and generalization conditions, as judged by root-mean-square error and correlation. Inferred trajectories were also matched to templates of lower lip, tongue tip, and tongue dorsum release gestures extracted from the original data. This technique correctly recognized from 94.4% to 98.9% of all gestures in the learning and cross-speaker generalization conditions, and 75% of gestures underlying consonants excluded from the training set. In addition, greater regularity was observed for movements of articulators that were critical in the formation of each consonant.


Native language factors affecting use of vocalic cues to final consonant voicing in English. Preceding vocalic information can cue final consonant voicing for native English speakers. This study examines subjects' use of two vocalic cues, vocalic duration, and F1 offset frequency, as a function of two native language factors, experience with final stop consonants, and experience with phonemic vowel length. Native speakers of English are compared to native speakers of Japanese and Mandarin Chinese who are learning English as a second language. Experiment 1 measured the F1 offset frequency and vocalic duration in productions of "pod" and "pot." Experiment 2 assessed identification of natural tokens of "pod" and "pot" with and without closure segments and bursts. Experiment 3 assessed categorization of synthetic "pod"-"pot" stimuli that systematically manipulated vocalic duration and F1 offset frequency. Native speakers of English showed the strongest implementation of and sensitivity to vocalic duration, Mandarin speakers showed significantly weaker effects, and Japanese speakers fell in between. Group-related differences in use of F1 offset frequency were smaller, and much clearer in the case of production than perception. It is hypothesized that a lack of experience with final consonants penalizes use of vocalic cues among the Japanese and Mandarin subjects, in general. The advantage of the Japanese subjects for use of vocalic duration further suggests a facilitation effect of experience with phonemic vowel length.


Phonetic prototypes: influence of place of articulation and speaking rate on the internal structure of voicing categories. In this investigation, the effects of context on the perception of voicing contrasts specified by voice-onset-time (VOT) in syllable-initial stop consonants were examined. In an earlier paper [J.L. Miller and L.E. Volaitis, Percept. Psychophys. 46, 505-512 (1989)], it was reported that the listener's adjustment for one contextual variable, speaking rate, was not confined to the region of the phonetic category boundary, but extended throughout the phonetic category. The current investigation examines whether this type of perceptual remapping also occurs for another contextual variable, the place of articulation of the syllable-initial consonant. In a preliminary experiment that involved acoustic measurement of natural speech, it was confirmed that as place of articulation moves from labial to velar, VOT increases, and it was established that this occurs across a range of speaking rates (syllable durations). In the main experiments, which focused on the voiceless category, it was found that this acoustic change was reflected in perception not only as a shift in the location of the voiced-voiceless category boundary, but also a change in both the specific range of stimuli identified as members of the voiceless category and the set of stimuli judged to be the best exemplars, or prototypes, of the category. These findings extend earlier research by showing that a change in place of articulation, like a change in speaking rate, systematically alters the internal perceptual structure of voicing categories.


Acoustic measures for linguistic features distinguishing the semivowels/wjrl/in American English. Acoustic properties related to the linguistic features which characterize the semivowels in American English were quantified and analyzed statistically. The features can be divided into those which separate the semivowels from other sounds and those which distinguish among the semivowels. The features of interest are sonorant, syllabic, consonantal, high, back, front, and retroflex. Acoustic correlates of these features were investigated in this study of the semivowels. The acoustic correlates, which are based on relative measures, were tested on a corpus of 233 polysyllabic words, each of which was spoken once by two males and two females. For the most part, the appropriate distinctions are made by the chosen acoustic properties for features. However, for each property, there was some overlap in the acoustic correlates of features for the sounds being distinguished. An examination of the sounds in the overlap regions reveals that their surface manifestation varies substantially from the canonical form. In large part, the observed variability can be explained in terms of changes due to feature spreading and lenition.


A cognitive influence on the loudness of tones that change continuously in level. The loudness of tones that change continuously in level over time was studied using magnitude estimation and a delayed loudness-balance procedure. In the magnitude estimation task, subjects estimated the loudness of continuous and intermittent 1000-Hz tones that either increased or decreased continuously in level over roughly 3 min. Two stimulus ranges were used: 30 to 70 and 50 to 90 dB SPL. For the low-level conditions, the results are essentially identical to those of Canévet and Scharf [J. Acoust. Soc. Am. 88, 2136-2142 (1990)], who ran similar conditions. Tones that increased in level changed in loudness as a function of SPL at a slower rate than tones that decreased in level. For the high-level conditions, the same result was obtained, but the magnitude of the difference among conditions is smaller. A delayed loudness-matching procedure was used to measure the physical magnitude corresponding to loudness differences among a subset of the conditions. Judged equal-loudness levels showed a sharp decline in loudness for conditions with tones that decreased continuously in level, but the magnitude of the reduction was less than that interpolated from magnitude estimates for identical stimuli. The source of the difference is unclear. To explore the role of cognitive influences, subjects' attention was diverted by a video word-identification task during the period of adaptation. For this task, the loudness decline was reduced for loudness balances and magnitude estimations compared to conditions where attention was concentrated on the adapting stimulus. In another magnitude-estimation task, the loudness decline for monaural stimulation was found to occur only in the "adapted" ear.(ABSTRACT TRUNCATED AT 250 WORDS)


Dynamic frequency change among stimulus components: effects of coherence on detectability. Experiments were performed to determine the effect of coherent dynamic frequency change among stimulus components on detection of one of those components. Detectability of a frequency glide signal, centered at 660 Hz, was measured in the presence of two additional frequency glides centered at 220 and 440 Hz. Results show that the signal is most difficult to detect when it is changing coherently with the other stimulus components, and that detectability gradually improves as the frequency change among stimulus components becomes less coherent. A control experiment indicated that detectability of the signal is influenced somewhat by the average spectral distance between the signal and the other stimulus components. In order to separate the effects of dynamic frequency change from those of altering harmonic relationships, the experiment was repeated with stimulus components not harmonically related. Results are similar in pattern, though with somewhat smaller shifts. A final experiment was performed to determine if the observed shifts in detectability might be due to changes in the maximum spectral distance between signal and masker when their frequencies are changing incoherently. Results of this experiment indicate that detectability improves when frequency change of signal and masker is not coherent, even when maximum spectral distance does not change. These data indicate the likelihood that the auditory system is able to use coherent dynamic frequency change among stimulus components.


Auditory filter bandwidths as a function of level at low frequencies (125 Hz-1 kHz). Auditory filter bandwidths were measured using the symmetric notched-noise method in five normally hearing listeners at four masker levels (40-70 dB SPL/Hz in 10-dB steps) and four probe frequencies (125-1000 Hz in octave steps). Accurate stimulus spectrum shape and level were ensured by use of a headphone monitoring technique. Auditory filter bandwidths decreased with decreasing frequency from 1 kHz down to 125 Hz. On the whole, bandwidths increased with increasing level, but the effect of level on bandwidth was greater as frequency increased, with little or no effect of level at 125 Hz. Insofar as the results from the notched-noise method reflect basilar membrane vibration patterns, basilar membrane mechanics appear to become less nonlinear as one approaches the apex of the cochlea.


Intensity discrimination in forward masking. A nonmonotonic intensity discrimination function was recently reported in which a midlevel hump occurred for 25-ms sinusoidal standards ranging from 20 to 100 dB SPL and presented 100 ms after an intense narrow-band noise forward masker [F.-G. Zeng et al., Hear. Res. 55, 223-230 (1991)]. This paper provides additional data on how the midlevel hump is affected by three factors of forward masking: signal delay, masker level, and frequency. Specifically, just-noticeable differences (jnd's) in intensity were obtained at signal delays of 50, 200, and 400 ms. Results show that at the midlevels the forward-masked intensity jnd's did not recover to their unmasked values, even at the 400-ms signal delay. The longer the signal delay, the smaller this midlevel hump. This slow recovery of the midlevel jnd's is consistent with the finding that low-spontaneous rate (SR) neurons have a slow recovery from forward masking [E. M. Relkin and J. R. Doucet, Hear. Res. 55, 215-222 (1991)]. The large midlevel effect decreased sharply as masker level was reduced from 90 to 60 dB SPL, and disappeared for masker levels less than 40 dB SPL. A frequency selectivity effect for the large midlevel jnd effect was also observed, as maskers with frequency components 2 to 3 oct away from the signal frequency did not affect the jnd's. Overall, the present data are consistent with the hypothesis of Zeng et al. (1991) that low-SR neurons are involved in the midlevel hump of intensity discrimination in forward masking.


On the consistency of tapping to repeated noise. Repeated noise at 1-4 cycles per second evokes an effortless heard rhythmic sensation which is often heard as "clanks" and "rasping." Tapping in synchrony with the period of the perceived structure is easy and consistent within one presentation. The present study addresses the question of whether the tapping to presentations at different times is consistent across presentations and across subjects. Nine listeners from three countries were presented with repeated Gaussian noise samples in 300 separate cyclical presentations. Nine samples of Gaussian noise with sample lengths ranging from 500 to 700 ms were used. In each of the presentations, one of these samples was selected at random and presented cyclically with transientless juxtapositions. The listeners were instructed to tap in synchrony with the perceived structure (i.e., once per period). Tapping to later presentations of a given sample was found to be consistent with prior tapping to the same sample: In most cases, one or two different tapping points per noise sample could be reproduced in different presentations. In the case of two possible tapping points in different presentations, the two points are usually far away from each other (most likely half a period away). The correlation between subjects is noticeable, although not perfect. The correlation between subjects of the same country is not significantly higher. The noise generating algorithm is given explicitly to allow subsequent studies to use exactly the same noises.


Use of sound-pressure level in auditory distance discrimination by 6-month-old infants and adults. Six-month-old infants have been found to respond differentially to sounding objects placed within reach and beyond reach when no visual cues were available. The goal of the present study was to investigate whether sound-pressure level (SPL) serves as an auditory cue in distance discrimination. Thirty-two 6-month-olds were presented with recordings of sounding objects first in the light at midline position, then in the dark at 45 degrees to the right and left. On half of the dark trials the object was near (15 cm), and on half it was far (100 cm). For the control group the near sound was naturally 7 dB louder than the far. The experimental group had SPL counterbalanced across near and far locations to provide an inconsistent cue. Measures of infant reaching were scored from videotape. Two groups of adults were run under similar conditions; adults were tested on reaching as well as verbal reports of distance judgment. All infants reached more for the near object, regardless of the sound's SPL, suggesting that infants did not rely on this as a major distance cue. In contrast, adults' verbal judgments of distance were based heavily on SPL, a strategy that produced higher error rates in the group with SPL counterbalanced across distance. A followup study in which adults were instructed to move their heads before judging the sound's distance did not support the hypothesis that infants' head movements were responsible for their overcoming the misleading SPL information.


Attenuation of sound by schooling fish.

Attenuation of sound by schooling fish. Attenuation of sound by schooling fish was measured or estimated for yellowtail (Seriola quinqueradiata), sea bream (Pagrus major), and spotted mackerel (Scomber australasicus) in culture nets and a net cage. The results, along with those of other researchers, are normalized to obtain extinction cross sections per 2/3 power of the body weight. In the normalized cross sections there are no large differences among fish species, sizes, and measuring methods. The attenuation increases slightly with the frequency. Attenuations to be encountered in field observations by echo sounders are estimated and the results reveal that ordinary fish schools do not attenuate sound significantly.


Career patterns and job satisfaction of Canadian nurse educators. The purpose of this study was to describe the career patterns and job satisfaction of Ontario university and college nurse educators. A descriptive survey design was employed using mailed questionnaires. The sample comprised 60 nurse educators, 30 from three universities and 30 from three colleges. Forty-four returned the completed questionnaire, giving a response rate of 73%. The variables about the career patterns and goals of the nurse educators included their past and present job satisfaction. Career patterns were described as stable, double-track, interrupted and unstable. Similarities and differences were compared and described in relation to these factors. Significant differences in job satisfaction were found between university and college faculty on nine of the 36 job characteristics (for example, leadership style, independence, autonomy and salary). There were no significant differences in job satisfaction for each of the career patterns and the selected demographic variables of age, years in nursing education, educational level and salary between the university and college faculty.


Client-public health nurse relationships in child health care: a grounded theory study. Client-public health nurse relationships are considered to be important in nursing literature. However, little research in nursing has touched this area. The purpose of this paper is to describe a study of the patterns of interaction in terms of relationships between clients (mother and child under 1 year of age) and public health nurses in child health care at Finnish health centres. The qualitative data were collected by observing client-public health nurse interactions during visits. In total, 1554 interactions were observed over 2 years from 20 visits to child health centres. The grounded theory method was used in this study. Various relationships were identified between child and mother, child and public health nurse and mother and public health nurse. The relationship between child and mother during the visit was called a tender, protective and persuasive relationship. The relationship between child and public health nurse was called a persuasive and entertainment relationship. The main relationship between mother and public health nurse was called relationship supporting self-confidence. Suggestions for nursing practice and further research are made.


Middle-Eastern immigrant parents' social networks and help-seeking for child health care. The purpose of this research was to describe: (a) Arab-American immigrant parents' perceptions of their social networks, including social support; and (b) Arab-American immigrant parents' perceptions of their help-seeking related to child health care. Seventy-three immigrant parents who were Egyptian-American (n = 17), Palestinian-American (n = 44) and Yemeni-American (n = 12) completed the Norbeck Social Support Questionnaire, four Supplementary Social Support Questions, a Support System Map and a Child Health Interview Guide. Family and relatives were perceived as the major source of support and comprised the highest percentage of social network members. Compared with published scores of a normative American sample, the immigrant parents' scores were lower (P less than 0.01) on all social network and social support variables. There was a moderate negative correlation (r = 0.47) between parents' number of years of residence in the USA and percentage of network members living outside the USA (P less than 0.01) and a weak positive correlation (r = 0.36) between number of years in the USA and percentage of network members living close to the parent (P less than 0.01). Parents' help-seeking for child health care involved use of a variety of resources, with reliance on some long-distance support from family in the Middle-East. This descriptive research provides a basis for further research on patterns of support and help-seeking in immigrant parents.


The non-existence of non-compliant families: the influence of Humberto Maturana. Non-compliance is not only an epistemological error but a biological impossibility. This profound statement arises from the influence of Humberto Maturana's revolutionary meta-theory of cognition. The definitions and significant implications of two major theoretical concepts of this meta-theory of cognition, namely structural determinism and objectivity-in-parenthesis, are discussed. These radical concepts challenge the approved North American Nursing Diagnostic Association's nursing diagnosis of non-compliance. Maturana's theory reveals the impossibility of instructive interaction, leading the authors to conclude the non-existence of non-compliant families.


Suffering: a relatively unexplored phenomenon among family caregivers of non-institutionalized patients with cancer. Suffering is a phenomenon with physical and emotional components. Although several studies have drawn attention to the needs of, and demands placed on families who provide care for patients with a diagnosis of cancer at home, few have discussed the suffering which many of these caregivers experience. This paper will illustrate the phenomenon of suffering as seen in the responses made by family caregivers of patients with cancer. Eighty-three family caregivers drawn from a probability sample of patients with a diagnosis of cancer were interviewed in their homes to determine needs they encountered in their caregiving roles. The caregivers consisted of 43 males and 40 females, with mean ages of 53 and 54 years respectively. Families not only identified their needs, they also indicated several areas which were for them sources of suffering. The findings revealed that family suffering often stemmed from fear of loneliness; uncertainty about the future (their own and that of the patients); lifestyle disruption; communication breakdown; lack of support; and their sense of helplessness. These findings suggest that health professionals, particularly nurses, who work with families in their homes, must be alert and sensitive to cues and circumstances which could indicate suffering, and in so doing, take the necessary steps to ameliorate their situation.


Effectiveness and cost efficiency of interventions in health promotion. The effect of a stress management programme as a component of an overall fitness programme was evaluated. Psychological, physiological and economic parameters were examined in relation to stress management activities in an experimental study. Subjects were stratified by life stressors and then randomly assigned to groups. Stress-related physical symptoms decreased significantly (P less than 0.05) in the treatment group. Those who practised the relaxation techniques regularly had significantly lower systolic blood pressure (P less than 0.05). Results of cost evaluation demonstrate the benefits from a programme with relatively low overall costs.


Coping: an essential element of nursing. How well a person copes is central in determining his or her well-being, no matter how ill he or she is. Without an accurate appreciation of what coping is and how it may be facilitated, attempts to help patients may be both ineffective and harmful. But the subject is multifaceted and poses many problems for clinicians and researchers alike. This paper attempts to synthesize available knowledge on coping from various disciplines and apply it to life as nurses know it.


The drama of nursing.

The drama of nursing. This exploratory paper considers a few possibilities for conceiving nursing as a form of aesthetic praxis. More specifically, drawing on the works of Erving Goffman on dramaturgy, and Elizabeth Burns on theatre, it makes some suggestions concerning nursing as a form of dramatic performance, and briefly attempts to relate this to concepts of praxis drawn from the writings of Hannah Arendt and critical social theorists. In contrast to Goffman's dramaturgy, which stresses the artifice of social relations and suggests a cynical view of human interactions, a critical theory of dramatic praxis introduces a normative dimension in which performance may become self-realizing and emancipatory as it aspires to the status of aesthetic praxis. Conceived in such terms, nursing practice becomes a powerful form of self-expression which has the potential to become liberating for the nurse and the patient.


The nature of dilemmas in dialysis nurse practice. Dilemmas are a part of nurse practice. In situations where a problem potentially has two or more unsatisfactory resolutions, the nurse chooses which course of action to take. The decision to choose constitutes a dilemma. This study focuses on the dilemmas faced by nurses in dialysis units and the context in which they occur. A qualitative design was employed, using open interviews with eight nurses currently employed in dialysis nursing. This approach was taken in order to explore and gain in-depth understanding of the dilemmas in practice. Analysis reveals that dilemmas encountered in dialysis nursing emerge from conflicts in relationships with other people in the work environment. The dilemmas relate to the nurses' perception of the limited power they have in the determination of their practice. This powerlessness is reinforced by their perceived and real isolation from nurses working outside their area of practice. Traditionally, literature on dilemmas in nursing has focused on the development of ethical frameworks to guide practice and the resolution of dilemmas. However, the findings of this study suggest that if nurses are to deal with dilemmas effectively, both for the nurse and the patient, there must be an examination of the structural constraints affecting their practice. Models that are employed by nurses to guide practice must account for the structural elements in the work environment.


Patient satisfaction with care in the emergency department. This paper looks at the patient satisfaction levels with care in an emergency department (ED) setting. Specific aspects of nursing care, information given to patients, auxiliary personnel and ED environment are examined in the light of the current literature on the subject. Recommendations for practice are provided to assist the nurse and administrator in updating their accountability to the ED patient.


Quality of life as quality of being: an alternative to the subject-object dichotomy. The opening section of this paper is concerned with certain questions concerning the concept 'quality of life'. Is it possible for one person to make judgements about the quality of life of another? If it is possible, then is it morally acceptable? Given that quality of life is a concept and therefore not amenable to direct observation, which visible phenomena will be chosen as its indicators, and how can their choice be justified? Do the components of a life of quality vary from person to person, or can features be identified which are common to all? Next, it is argued that instruments which have been developed to measure quality of life give clues to the ontological beliefs of their authors; those which address fragments of the human experience, or accept the artificial limits of the subjective/objective dichotomy, are expressive of a fractured and reductionist view of what it means to be a human being. Finally, it is suggested that the adoption of insights drawn from Heidegger's work would enable us to develop a rather more unified view of quality of life as quality of being, and that this theoretical principle might constitute a common link between nurses of varying professional backgrounds.


Labelling students in nursing.

Labelling students in nursing. This paper is concerned with the factors which can lead to the labelling of students in nursing. It commences with some of the considerations involved when one elects to enter a profession. This is examined in the light of changing ideologies about the ways in which it is believed that nurses should be taught and whether teaching aims to train or educate nurses. This analysis is applied to the issues that arise in terms of labelling students, and the possible subsequent effects on the students' capacity to succeed. The continuing dissonance inside the educational environment and between education and clinical practice are proposed as contributory factors in the processes that can lead to student frustration and disenchantment. Finally, some suggestions are made to attempt to address these issues.


The relationship between locus of control, instrumental and expressive traits among nurses. The purpose of this study was to explore the relationship between locus of control and sex role orientation among nurses. Ninety-eight participants, working female registered nurses between the ages of 30 and 59, were placed into one of four sex type groups using scores on the Personal Attributes Questionnaire. The groups were then compared to each other using Rotter's Locus of Control Scale. Previous research findings had indicated that women in a traditional female occupation would be sex typed in role orientation and externally locused. The subjects in this study exhibited variability in locus of control and sex role orientation. Locus of control orientation was not related to sex role orientation. The implications of the results were discussed and directions for future research were considered.


Facilitator not teacher: a role change for tutors in open learning nursing education. Open learning is now an established, if rapidly changing, part of post-compulsory education and training in the United Kingdom. It has also developed in significant ways within nurse education. A key role in successful open learning is that of the tutor. Differences between the activities of teaching and facilitation are defined and ways of mapping the tutor's role within these are suggested. Differences in approach can be clustered around the topics of: the locus of control; learning methodology; the learning context and media; and the curriculum. These are discussed in turn to elicit what are the key issues for tutoring in relation to each one.


Using a manpower database to analyse the nurse limbo stock. A manpower database for nurses employed by the Department of Health and Social Services (DHSS) in Northern Ireland is used to identify the qualified nurses not currently employed by the DHSS, i.e. the limbo stock, and describe this stock in terms of age, sex, length of previous service, grade and location. This information is invaluable for manpower planners who must decide on how many vacancies can be filled by recruitment from the limbo stock, as opposed to training new nurses. Such a methodology provides a valuable tool for the nurse manpower planner.


Freshmen baccalaureate nursing students' perceptions of their academic and nonacademic experiences: implications for retention. As a component of the evaluation for a program designed to enhance recruitment and retention of disadvantaged nursing students, qualitative interviews were conducted, with a sample of 20 baccalaureate nursing students at the end of their freshman year. Students were asked to describe positive aspects of their academic and nonacademic experiences as well as problems that were experienced, with recommendations for resolving these problems. Positive aspects of the freshman experience that were identified included academic, social, familial, and financial support. Problems cited were related to two categories of factors, external and internal. Problems related to external factors included excessive academic loads, course-specific problems such as with the sciences, large class size, faculty inattentiveness, racial tensions, dorm/roommate problems, and parking or commuting time. Problems related to internal factors included poor study habits, loneliness, homesickness, family conflicts, and difficulties with peer relationships. The findings can be used by nursing faculty to determine the extent to which programs address students' perceived needs and to identify innovative retention strategies that would enhance students' perceptions of their college experience.


Psychiatrically hospitalized college students: a pilot study. This pilot study presents data on an underreported group: college students who require psychiatric hospitalization. Although the study is too small to sustain broad generalizations, the authors found indications of significant correlations between students' hospitalization and the academic cycle, substance abuse, and distance from home. It is hoped that other institutions will undertake similar studies of this group of students to provide a broader body of data from which to draw inferences regarding prevention, intervention, and psychiatric hospitalization.


Spiritual well-being: a predictor of hardiness in patients with acquired immunodeficiency syndrome. This study examined the relationship between spiritual well-being and hardiness in a group of 100 subjects who either tested positive for the human immunodeficiency virus (HIV+) or who had diagnoses of acquired immunodeficiency syndrome (AIDS)-related complex (ARC) or AIDS. Each subject completed the Spiritual Well-Being Scale, the Personal Views Survey (to measure hardiness), and a Demographic Data Survey. Analysis of data included Pearson Product-Moment Correlation Coefficients and multiple regression techniques. The results demonstrated that there was a significant relationship between spiritual well-being and hardiness (multiple R = .4165; P less than .001) as well as between the existential component of spiritual well-being and hardiness (multiple R = .5047; P less than .001). The conclusions of the study are that in this sample those individuals who were spiritually well and who were able to find meaning and purpose in their lives were also hardier. This finding has significance for the care that is provided to persons who are HIV+ or who have diagnoses of ARC or AIDS.


Screening for Chlamydia trachomatis in college women on routine gynecological exams. Chlamydia trachomatis infection poses a serious threat to sexually active college women. Past research has demonstrated the difficulty of predicting infection on the basis of symptoms or physical exam. Recent studies highlight the prevalence of asymptomatic chlamydia infections. This study presents the results of screening 2,303 women for chlamydia infection on routine annual gynecological examinations at a college health center during a 22-month period. A prevalence of 6% was found. The study also assessed the differences between the 140 women identified as chlamydia positive and a control sample of 140 women who were chlamydia negative. The authors compared groups for signs and symptoms that might predict infection, but found no useful predictors. In fact, 79% of the patients who tested positive had no symptoms, and 58% of these had no signs, symptoms, or concurrent infections. Routine screening of women on annual gynecological exam is necessary to bring the chlamydia epidemic under control, the authors conclude.


Refusal to care for patients with human immunodeficiency virus/acquired immunodeficiency syndrome: issues and responses. Nurses historically have accepted the risk of contagion while caring for patients with infectious diseases. The duty to care for patients is directly related to the care the patient requires, the nurse's knowledge, and the extraordinary risk to the nurse. The current infection with human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) highlights other factors, such as fear, ignorance, and homophobia, that influence a nurse's decision to refuse to provide care. Professional associations, nurse administrators, and educators must assist nurses to gain the knowledge and skill necessary to provide care as well as explore feelings about different life-styles.


Judgment: the nurse's key to knowledge.

Judgment: the nurse's key to knowledge. Recently, nursing has turned more of its attention to judgment and has given it a high priority for study. A significant part of that study asks: What is judgment? How is it made? Why is it important? The ancient Greeks discovered reason and then created enduring art that demonstrates it. Three nurses are excerpted from this literature to evoke and explain how judgment is made. Euryclea, Cilissa, and Medea's nurse also illustrate the personal commitment in judgment. Human beings depend on the nurse's judgment. They depend on the nurse as knower. Nurses are obliged to move from doubt and opinion towards knowledge and certitude. Judgment is the nurse's key to that knowledge.


Student mental health needs: survey results and implications for service. In preparation for planning counseling and mental health services at Columbia University, the authors conducted a mental health needs assessment survey that sampled representative numbers of students. Respondents were most concerned about academic and school-related issues, followed by concerns in the area of love relationships. Multiple regression analysis revealed certain subgroups that were more likely to have these concerns and certain health and mental health problems that were significantly associated with these concerns. The study identified serious psychological problems, including suicidal/homicidal thoughts and sexual abuse, and surveyed respondents' treatment preferences. Finally, the authors discuss how the study findings contributed to sharpening and expanding focus on different aspects of program development in the collaboration between mental health and health education.


Sexual behavior patterns of gay university men: implications for preventing HIV infection. Gay male university students less than 25 years old were studied to determine whether they had changed their sexual activity patterns to reduce the risk of HIV infection. Most had not established sexual behavior patterns typical of the older gay men who had been studied in earlier research. Although most of the participants surveyed were concerned about HIV infection, some did engage in risky sexual behavior. The risk-reduction strategies most often used were having fewer sexual partners and being more selective in choosing partners. Future HIV-prevention interventions must be designed to address the needs of this generation of gay men.


The status of nutrition education in ACHA college and university health centers. An assessment of the prevalence and scope of nutrition services offered through 208 randomly selected American College Health Association member student health centers revealed that 79% of the 160 respondents provided some type of nutrition education for students. One-to-one counseling, available at 96% of the institutions, was the most common approach. The larger the school's enrollment, the more likely it was to provide programs in nutrition. All of the institutions with student populations of more than 35,000 offered some type of nutrition service, as did 52% of the 19 schools with enrollments between 2,000 and 5,000. Health educators, nurses, doctors, dietitians, and trained peer educators provided the services, with registered dietitians the most common providers and often coordinators of the programs. Costs to students for nutrition interventions were nominal; weight-management programs were the most expensive and showed the greatest variation in content.


A statewide consortium initiative to establish an undergraduate clinical internship program. The amount of time and the type of experience needed by undergraduate students in the clinical setting to actually practice nursing has been the subject of many debates between nurses in academe and service. Rather than blaming each other for the culture shock and transition problems of neophyte nurses, members of the academic and practice community in Rhode Island decided to address the problem together. The development of the collaborative program described in this article grew out of a research study and was coordinated through the efforts of nurses from service and academe. The central outcome of this statewide consortium's project was to increase the students' level of nursing competencies. "Turf" issues that related to the colleges and the hospitals involved became secondary. Everyone involved believed that students from different collegiate programs working together presented exciting opportunities to share and learn from one another. In addition, other outcomes included increased recruitment and retention of these baccalaureate-prepared nurses in the hospitals, and greater ease in their orientation and transition. In addition, a cluster of three research studies were conducted by members of the consortium. This ongoing program, in which nurses in education and service are working together in a statewide consortium to break down the turf issues that separated them, is achieving outcomes that could not have been accomplished had it been undertaken independently. This article describes the process used to develop, implement, and evaluate such a program.(ABSTRACT TRUNCATED AT 250 WORDS)


Barriers to health care for Vietnamese refugees. This study was undertaken to determine the dynamics of why Vietnamese refugees may not optimally use existing health services in the United States. A random sample of 75 refugees was interviewed by a bilingual translator. Multivariate analysis of variance was used to analyze the effects of time of arrival on whether the following are barriers to care: not having a translator available in health care facilities, feeling understood by health care providers, being able to understand the written and verbal instructions of providers, and not having a primary provider. The hypothesis, that time-of-arrival groups would differ significantly on these variables, was supported (F = 4.81; df = 8,136; P less than .001). Concern about not having a translator in health care facilities ranked first in distinguishing the groups (F = 17.09; df = 2.71; P less than .001), followed by primary provider (F = 5.68; df = 2.71; P less than .01), feeling understood by the provider (F = 5.15; df = 2.71; P less than .01), and being able to understand written and verbal instructions given by the provider (F = 4.25; df = 2.71; P less than .05). The time-of-arrival groups also differed significantly on supplemental analyses. Subjects expressed willingness to seek more frequent health care if translators were available in health care facilities (F = 18.22; df = 2.72; P less than .001) and to change health care sites to gain a translator (F = 13.74; df = 2.72; P less than .001).


Are we making any progress?

Are we making any progress? This report offers a limited view, by example, of dentistry's multifaceted interactions with several agencies on selected issues. It is intended to be neither comprehensive nor predictive.


Legally speaking: when dentistry and government clash in court. This article focuses on ADA advocacy in the courts. As these cases illustrate, organized dentistry's relationship can be adversial when cooperation fails. But that doesn't mean there is no room for agreement.


Analyzing dental procedures performed by an HIV-positive dental student. No evidence of HIV transmission was found between an HIV-positive dental student and 163 treated patients.


Reattaching fractured tooth segments: an esthetic alternative. Reattaching fractured tooth segments offers an esthetic transitional restorative alternative to bonded composite and full crowns. The authors review this technique and demonstrate its application.


Suture removal-induced bacteremia: a possible endocarditis risk. Multiple intraoral suture removal isn't always a benign procedure for cardiac patients at high risk from bacteremia. Under certain conditions, antibiotic prophylaxis is recommended.


Third molars and incisor crowding: when removal is unwarranted. Recent evidence indicates that extracting unerupted mandibular third molars neither decreases interdental force measurably nor prevents mandibular incisor crowding. There are valid reasons for extracting third molars. But extraction for the exclusive purpose of relieving interdental pressure and thereby preventing incisor crowding is unwarranted.


Recollections of pioneers in nutrition: landmarks in the development of parenteral nutrition. Total parenteral nutrition (TPN) has been available for only 30 years. The successful development of this therapy, in a modern sense, was initiated in the late 30s. However, history in this field goes back more than 350 years, with the first landmark being the description of general blood circulation by William Harvey in 1628. His discovery is the anatomical basis for intravenous infusions. Many investigations were performed during the following centuries showing that solutions containing electrolytes and glucose could be given intravenously in man. The accumulated knowledge of protein metabolism formed the basis for studies on intravenous nutrition with protein hydrolysates, peptides and amino acids. The observation in the late 30s by Robert Elman that amino acids in the form of protein hydrolysate could be administered safely in man was the first major step toward TPN. During the following years, major efforts were made to find methods to prepare infusion solutions with a high energy content and low osmotic pressure. The most realistic alternative seemed to be fat in the form of an emulsion. Many studies of a large number of various fat emulsions were made from the 20s until the end of the 50s. However, all of these emulsions caused severe adverse reactions in man. The first safe fat emulsion, Intralipid, was made available in the early 60s. This was the second major step toward TPN. It was then no problem to include vitamins, electrolytes and trace elements in the fat emulsions and the solutions of amino acids and glucose.(ABSTRACT TRUNCATED AT 250 WORDS)


Dietary palmitic and oleic acids exert similar effects on serum cholesterol and lipoprotein profiles in normocholesterolemic men and women. To compare the effects of dietary palmitic acid (16:0) vs oleic acid (18:1) on serum lipids, lipoproteins, and plasma eicosanoids, 33 normocholesterolemic subjects (20 males, 13 females; ages 22-41 years) were challenged with a coconut oil-rich diet for 4 weeks. Subsequently they were assigned to either a palm olein-rich or olive oil-rich diet followed by a dietary crossover during two consecutive 6-week periods. Each test oil served as the sole cooking oil and contributed 23% of dietary energy or two-thirds of the total daily fat intake. Dietary myristic acid (14:0) and lauric acid (12:0) from coconut oil significantly raised all the serum lipid and lipoprotein parameters measured. Subsequent one-to-one exchange of 7% energy between 16:0 (palm olein diet) and 18:1 (olive oil diet) resulted in identical serum total cholesterol (192, 193 mg/dl), low-density lipoprotein cholesterol (LDL-C) (130, 131 mg/dl), high-density lipoprotein cholesterol (HDL-C) (41, 42 mg/dl), and triglyceride (TG) (108, 106 mg/dl) concentrations. Effects attributed to gender included higher HDL in females and higher TG in males associated with the tendency for higher LDL and LDL/HDL ratios in men. However, both sexes were equally responsive to changes in dietary fat saturation. The results indicate that in healthy, normocholesterolemic humans, dietary 16:0 can be exchanged for 18:1 within the range of these fatty acids normally present in typical diets without affecting the serum lipoprotein cholesterol concentration or distribution. In addition, replacement of 12:0 + 14:0 by 16:0 + 18:1, but especially 16:0 or some component of palm olein, appeared to have a beneficial impact on an important index of thrombogenesis, i.e., the thromboxane/prostacyclin ratio in plasma.


Nutritional modulators of lipoprotein metabolism in patients with risk factors for coronary heart disease: diet and moderate exercise trial. To study the role of diet as a risk factor for coronary heart disease (CHD), 463 adults (25-65 years, 419 males) at risk of or with CHD were assigned to group A (n = 231) receiving a cardiovasoprotective diet or group B (n = 232) receiving a normal diet in a randomized, single-blind fashion. Age, sex, risk factors and incidence of CHD were comparable between the two groups. Group A received a significantly higher percentage of calories in relation to complex carbohydrates, vegetable proteins, polyunsaturated fatty acids, and had a higher polyunsaturated:saturated fatty acid (P:S) ratio compared to control group B, which received more saturated fat and cholesterol. Group A also received more soluble dietary fiber and magnesium (Mg) and was physically more active than group B. Exercise and dietary adherence were tested by a questionnaire. After 12 weeks, results indicated a significant decrease in mean serum total cholesterol (9.0 vs 3.1%), low-density-lipoprotein cholesterol (LDL-C) (9.8 vs 3.8%) and triglyceride (11.1 vs 5.4%), and an increase in serum Mg (8.5%) in the intervention group compared to initial levels. No significant changes in mean levels were noted in the control group. Body weight significantly decreased and physical activity was significantly higher in the intervention group compared to the control group during the 12-week followup on similar intakes of energy. There were insignificant changes in high-density-lipoprotein cholesterol (HDL-C) in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)


Copper deficiency in rats: the effect of clofibrate. This study was undertaken to determine whether hepatic lipogenesis plays a role in the exacerbation of copper (Cu) deficiency. Forty-eight male rats were fed from weaning a Cu-deficient or adequate diet containing 62% carbohydrate as either starch or fructose with or without clofibrate for 5 weeks. Clofibrate was fed since it had been shown to possess hypolipidemic properties. Administration of clofibrate reduced the activity of the lipogenic enzyme glucose-6-phosphate dehydrogenase. Total hepatic lipid, however, was not reduced. Clofibrate did not affect hepatic lipid concentration and the pathology associated with Cu deficiency when fructose was fed was not prevented by the consumption of clofibrate.


Electrophysiologic effects of magnesium sulfate infusion in patients with cardiac conduction defects. We report the electrocardiographic and electrophysiologic effects of magnesium (Mg) sulfate infusion in 25 normomagnesemic patients (16 men and 9 women, aged 22-74 years; mean +/- SD, 60.4 +/- 11.9) with different cardiac conduction impairments. Ten patients had chronic ischemic heart disease, two had idiopathic dilated cardiomyopathy, two had hypertensive heart disease, three had valvular heart disease, five had sclerodegenerative heart disease and three had no clinical evidence of cardiac disease. Five patients had trifascicular block [first degree atrioventricular (A-V) block+right bundle branch block (RBBB)+left anterior hemiblock (LAH)], eight had bifascicular block (6 RBBB+LAH, 2 first degree A-V block+RBBB), four had isolated first degree A-V block and eight had bundle branch block [5 RBBB, 3 left bundle branch block (LBBB)]. Before and during Mg infusion (50 mg/min/60 min) we evaluated the A-V (P-R), intraatrial (P-A), suprahisian (A-H), infrahisian (H-V) conduction times, electrical ventricular systole (Q-T), Q-T index (Q-Tc) intraventricular conduction time (QRS) and heart rate. At the end of infusion the P-R, P-A, A-H, H-V increased from 215.4 +/- 36.6, 33.6 +/- 9.1, 112.8 +/- 37.3, 69.0 +/- 12.8 ms to 217.6 +/- 37.1 (p less than 0.002), 33.8 +/- 9.4 (NS), 114.2 +/- 38.1 (p less than 0.005), 69.6 +/- 13.3 (NS) ms. QRS complex did not change (125 +/- 16.9 ms).(ABSTRACT TRUNCATED AT 250 WORDS)


Plasma and erythrocyte magnesium changes following a glucose challenge during pregnancy. This study examined the effects of pregnancy and glucose loading on plasma and erythrocyte (RBC) magnesium (Mg) concentrations. In a completely randomized design with repeated measures, 15 nonpregnant, 15 early pregnant (13-17 weeks) and 15 late pregnant (28-34 weeks) women ingested 100 g glucose. Blood was collected at 0, 30, 60, 120 and 180 minutes to evaluate changes in Mg levels. Fasting plasma Mg concentrations decreased slightly but not significantly as gestational age of the groups increased. Fasting RBC Mg concentrations were significantly higher (p less than 0.05) in late pregnant women compared with early pregnant and nonpregnant women. Plasma Mg responses to a glucose challenge in nonpregnant women exhibited a curvilinear pattern whereas responses in pregnant women appeared unaffected by the glucose challenge. RBC Mg concentrations for nonpregnant and early pregnant women failed to respond to the glucose challenge whereas it decreased in a linear pattern during late pregnancy. The diabetogenic effect of late pregnancy appears to affect RBC Mg. This redistribution of Mg during late pregnancy could suggest a possible role for RBC as a Mg pool.


Institutionalized elderly women have lower food intake than do those living more independently (Dutch Nutrition Surveillance System). The habitual intake of energy and nutrients (assessed through dietary history) among elderly women (aged 65 and over) living in a nursing home (n = 54), elderly women living in service flats and receiving their dinners from the nursing home kitchen (n = 29), and elderly women living independently (n = 52) was evaluated within the framework of the Dutch Nutrition Surveillance System. Intake of energy and nutrients was lowest among women in the nursing home and highest among those living independently. Almost all differences in absolute intake found were significant, both unadjusted and adjusted for age. In the nursing home the intake of energy and nutrients was lower at higher age. In qualitative terms the differences among the groups of women were less striking. Mean daily intakes of iron, vitamin A, thiamin, vitamin B6 and vitamin C were below the Dutch recommended dietary allowances (RDAs) among the nursing home women. Several interrelationships among nutrient intakes were found, low intake levels clustering somewhat among elderly subjects. Our data indicate that these nutritional risks are due to a lower food intake resulting in a lower intake of energy and nutrients, and owing to differences in food choice resulting in a lower nutrient density. We conclude that it is difficult to design a diet containing all essential nutrients at the RDA level in a nursing home with residents who have a relatively low intake of energy, especially among those at higher age.


Vitamin E status of US children.

Vitamin E status of US children. Data from several national surveys consistently show that American children have lower than recommended intakes of vitamin E, which is reflected in lower than average serum levels. Reduction in dietary fat can further exacerbate the low vitamin E status of children. The consequences of low vitamin E intake may include impaired immune responses, as seen in a study of over 500 Canadian children. Low vitamin E status has been correlated with increased risk of atherosclerosis and cardiovascular disease, cancer, cataract and impaired immune responses in adult populations. Since early signs of chronic degenerative diseases of aging have been seen in autopsies of children, efforts should be made to ensure that prolonged low intakes of vitamin E are avoided in children as well as adults.


A review of cancer cachexia and abnormal glucose metabolism in humans with cancer. In 1919, glucose intolerance became the earliest recognized metabolic abnormality in cancer patients. Prior to the development of severe malnutrition, colon, gastric, sarcoma, endometrial, prostate, localized head, neck, and lung cancer patients had many of the metabolic abnormalities of type II (noninsulin dependent) diabetes mellitus. These metabolic abnormalities include glucose intolerance, an increase in both hepatic glucose production (HGP) and glucose recycling, and insulin resistance. In a study of over 600 cancer patients, a diabetic pattern of glucose tolerance test was noted in over one-third of the patients. An increased rate of HGP, commonly seen in diabetics, has been noted in almost all types of cancer patients studied to date. Etiology of the increased glucose production in the cancer patient is not known, but abnormalities in the counter regulatory hormones, especially growth hormone, may contribute to the development of abnormal glucose metabolism. A second possible stimulus for the increase in HGP could be the glucose needs of the tumor. Abnormally high glucose utilization rates in small amounts of tumor tissue have recently been described. This suggests that small tumors may have large needs for glucose calories. An increase in anaerobic glycolysis in the tumor tissue can increase lactate production in the tumor-bearing human, thus supplying substrate to the liver to increase glucose production rates. In this paper, the nature of abnormal glucose metabolism in cancer patients is described.


Morbid obesity: selection of patients for surgery. Massive obesity is associated with serious co-morbidities. After failure of extensive conservative measures, surgical procedures have developed as the only successful method for sustained weight loss. Criteria for operation are: presence of serious diseases associated with morbid obesity; greater than 45 kg above ideal weight or body mass index greater than 40 kg/m2 for usually greater than 5 years; failure of sustained weight loss on extensive conservative regimens; commitment to lifelong follow-up; and acceptable operative risk. Angina pectoris itself is not a contraindication to these operations. Patients who do not quite meet the weight criteria may still be candidates for an obesity operation in certain instances, e.g., debilitating musculoskeletal pains in weight-bearing joints, diabetes, significant hypertension, reflux esophagitis, urinary stress incontinence. Although current operations result in lasting weight loss of greater than 50% of excess weight in the majority of patients, the surgical candidate must understand and accept the principles of the procedures, the potential for serious complications, the dietary necessities, and occasional failures.


Sports vision and the high school student athlete. Thorough sports vision evaluations (SVE) utilizing a 30-test battery of established sports vision tests, variations of commonly accepted procedures, and newly designed instruments and/or methods were performed by the Wisconsin Sports Vision Project (WSVP) staff on 232 teenage male and female high school student athletes. Tests are described and results reveal that a state tournament qualifying girls volleyball team (n = 8) demonstrated significantly better visual skills and abilities than 1) the male and female general high school athlete sample (n = 224), 2) the female athlete sample (n = 78), and 3) the other female volleyball players in the sample (n = 46) in some areas of dominant eye vision contrast sensitivity, distance judgement, dynamic visual acuity, tachistoscopic skills, low light and glare-affected vision.


Dichromacy and its effect on a young male. Deuteranopia is a dichromatic color vision defect which may cause problems for an individual asked to perform color-oriented tasks. This can especially create problems for grade school children in classrooms whose instructional material depends heavily on color. This case report presents a child with a deuteranopic color vision defect who was mistakenly labeled learning disabled because of his inability to learn and perform color oriented tasks.


Inferior punctal occlusion with removable silicone punctal plugs in the treatment of dry-eye related contact lens discomfort. Thirty subjects complaining of a decrease in soft contact lens wearing time secondary to dry eye discomfort were selected for our study. All subjects were between the ages of 25 and 40 and selected on the basis of subjective dry eye complaints alone. Five of these subjects had punctum that were too small to facilitate plug placement and were therefore eliminated from further study. Removable silicone punctal plugs were monocularly placed in the lower puncta of the remaining 25 subjects. In an attempt to minimize the placebo effect, both puncta were manipulated equally prior to plug insertion and the patient was not told which eye had been treated. Three weeks following plug placement, blind data assessment showed that 18 of the 25 subjects reported, on average, a 34.6 percent increase in comfortable contact lens wearing time in the treated eye. Three subjects reported no subjective increase in comfortable wearing time and four subjects were unable to tolerate the punctal plugs for more than a week due to plug-related discomfort. Problematic epiphora was not reported in any of the treated eyes. Reversible inferior punctal occlusion, when tolerated, can significantly increase comfortable contact lens wearing time while still allowing enough drainage from the upper puncta to prevent epiphora.


Pigment dispersion syndrome and pigmentary glaucoma. The pigment dispersion syndrome is a relatively uncommon condition, occurring as a result of pigment loss from the posterior-pigmented epithelium of the iris, with subsequent redeposition of the pigment throughout the anterior chamber. Obstruction of the trabecular meshwork occasionally leads to pigmentary glaucoma, with increased intraocular pressure, optic nerve head changes, and visual field loss. We present two cases of pigmentary dispersion syndrome, one of which progressed to pigmentary glaucoma with the eventual need for laser trabeculoplasty.


The True Daylight Illuminator (TDI): a less expensive source of illumination for color vision screening. This experiment was designed to examine the feasibility of using the True Daylight Illuminator (TDI) as an illumination option for conducting color vision screening with the Ishihara Test(s). The MacBeth Easel Lamp was designed to provide proper illumination for performing color vision screening with a variety of pseudoisochromatic (PIC) plate tests including the Ishihara. However, over the years, the MacBeth Lamp has become so expensive that many smaller programs cannot afford to purchase one. This problem has promoted the use of alternate light sources that have had a deleterious effect on test results and in some instances contributed to job discrimination. Recently the MacBeth Division of the Kollmorgan Corporation discontinued the manufacture of the MacBeth Lamp due to lack of demand. Thus, it is important to find an inexpensive illumination option for conducting color vision screening. Two groups of subjects were used to compare test results for the 24-plate edition of the Ishihara Test using both the MacBeth Lamp and the True Daylight Illuminator. The first group contained 45 subjects with inherited color defective vision. The second group was made up of 30 color normals. The Nagel anomaloscope was used to confirm the color vision status of the subjects in both groups. Statistics to test the significance of differences between group means clearly demonstrated that there were no significant differences between the mean error scores of the two groups for these two pieces of equipment. Thus, it was concluded that the TDI can be used in lieu of the MacBeth Easel Lamp for screening color vision with the Ishihara test.


Retinopathy of prematurity--review of the pathophysiology and classification. This paper provides an update on current concepts concerning retinopathy of prematurity (ROP). It considers the history, risk factors and pathophysiology of ROP as well as clinical recognition of the condition. The paper also describes the approved method of classification of the disease and presents treatment options.


A 1988 survey of federal service optometrists. A mailed questionnaire was used to survey federal service optometrists in the U.S. Air Force, U.S. Army, U.S. Navy, U.S. Public Health Service, and the Department of Veterans Affairs. The purpose of this survey was to determine the scope of practice and level of job satisfaction of these optometrists. The results of the study were compared with those of a similar survey conducted 5 years earlier.


Conservative and surgical management of incidentally discovered adrenal tumors (incidentalomas). Of 50 patients with incidentalomas (INC), 18 were adrenalectomized and in 18 patients the INC was left in place. For 14 patients clinical data were insufficient for evaluation. Follow-up investigation of the 18 unoperated subjects 11-101 months (median 32.2) after the diagnosis had been made revealed unchanged size of the INC [initially 2.1 +/- 0.8 cm (mean +/- SD) at follow-up 2.0 +/- 1.0 cm]. Cushing's syndrome developed in one patient, which was not evident at the initial discovery of the INC 32 months before. "Pre-Cushing's Syndrome" was detected in 1 patient and confirmed in a second who had displayed a pathologically high dose dexamethasone suppression test 101 months before. In addition, 3 male patients with a hitherto unknown mild subclinical defect of 21-hydroxylase activity were identified. The remaining 12 patients had normal endocrine activity of their adrenals. Eighteen patients were adrenalectomized with an average tumor size of 3.96 +/- 1.88 cm. Histologically, 10 (52%) adenomas were observed, including 3 with signs of hypercortisolism. Adrenal hyperplasias were observed in 2 patients, metastasis in 1 patient. 31.5% of the INC which were removed were nonmalignant tumors of other than adrenal origin. We conclude that initially endocrinologically inactive adrenal tumors can eventually develop autonomous endocrine activity and therefore need to be reexamined at regular intervals. Conservative management with regular follow-up investigations is the preferable treatment for small incidentalomas when endocrine over-activity has been excluded and no indications of malignancy exist. Based on these observations and the literature a diagnostic and therapeutic strategy is presented.


Weight reduction lowers blood pressure independently of salt restriction. The existence of a link between obesity and hypertension is nowadays universally accepted; however, there are still some doubts about the fact that weight reduction induces a significant long-term decrease in blood pressure. This clinical trial aimed at evaluating the effects of marked weight loss (at least 30% of excess body weight) induced by a low-energy (600 Kcal), normal sodium diet in severely obese patients, on blood pressure at rest and during sympathetic stimulation. Eight of the 20 patients initially recruited for the study were able to reach the therapeutical goal and brought their body weight from 107 +/- 6 to 91 +/- 4 kg. Their blood pressure (BP) at rest was at the same time reduced from 137/81 +/- 5/4 to 122/74 +/- 4/4 mmHg. Also, blood pressure measured during three different stimuli (cold pressor test, handgrip and mental arithmetic test) was lowered by this nonpharmacological means. These effects are related solely to weight reduction, since no change in salt intake occurred, as demonstrated by measurements of the 24-h sodium excretion test (191 +/- 13 vs 185 +/- 10 mEq/24 h). In conclusion, these results support the hypothesis that a drastic weight loss, independently of salt restriction, significantly reduces BP at rest and during stimulation of the adrenergic nervous system.


Direct effects of protirelin (TRH) on cultured porcine thyrocytes. In several cases of thyroid adenoma in which no TSH was detectable in the serum, a paradoxical decrease of PB123I and its conversion rate Q (PB123I/serum total radioactivity) was observed after infusion of protirelin (TRH). The possibile direct effect of TRH on thyrocytes was therefore studied in vitro. Porcine thyroid cells were cultured in NCTC-135 medium supplemented with a serum substitute and insulin. TRH and some of its analogs enhanced the incorporation of [3H]thymidine into DNA and the uptake of radioiodide into thyrocytes. In the presence of TSH, TRH did not stimulate radioiodine uptake, whereas incorporation of [3H]thymidine into DNA was not antagonized by TSH. Thus, in this culture system, TRH had a direct effect on both growth and metabolism of thyrocytes. TSH can modulate these effects.


Percutaneous intranodular ethanol injection: a new treatment for autonomous thyroid adenoma. Established methods for definitive ablation of autonomous thyroid nodules are surgery and radioiodine. Since it has been demonstrated that percutaneous ethanol injection can inactivate parathyroid adenomas and small hepatocellular carcinomas, we started a trial of this treatment in patients with autonomous thyroid nodules. Twenty-eight patients, 22 toxic and 6 nontoxic, all with undetectable thyrotropin serum levels and suppressed extranodular tissue on scintigraphy, were treated. Treatment consisted of percutaneous intranodular ethanol injection under ultrasound guidance. The total amount of alcohol injected ranged from 0.4 to 2.2 times the estimated nodule volume, divided into 4 to 9 injections performed at 2 to 7 day intervals. Most patients were treated with a single cycle of injections, but 7 of them required 2 cycles. The signs and symptoms of hyperthyroidism disappeared in all cases. Apparently complete cure (normal serum free thyroid hormones, thyrotropin in basal conditions and after thyrotropin releasing hormone, reactivation of extranodular tissue on scintigraphy with nodule no longer visible) was obtained in 17 patients (13 after 1 cycle and 4 after 2 cycles). Partial cure (normal serum free thyroid hormone levels, detectable thyrotropin levels with normal or blunted response to thyrotropin releasing hormone and partial reactivation of extranodular tissue on scintigraphy with nodule or parts of it still visible) was obtained in 10 patients (8 after 1 cycle and 2 after 2 cycles). In 1 patient with a very large nodule thyrotropin levels remained undetectable, but thyroid hormone levels eventually became normal. No recurrences were observed after a follow-up of 12 to 32 months (mean 20 months). No serious side effects were encountered. A clinically valuable result was obtained in all patients. These data suggest that this form of treatment could constitute an alternative to surgery and radioiodine for the ablation of autonomous thyroid nodules.


A case of rheumatoid arthritis associated with silent thyroiditis. A 41-year-old female with rheumatoid arthritis had nontender enlarged thyroid gland. Thyroid function tests revealed increased concentrations of serum free T3 (FT3, 10.8 pmol/L) and free T4 (FT4, 31.1 pmol/L) with suppressed concentration of thyrotropin (TSH, lower than 0.1 mU/L) and low 24-hour thyroidal radioactive iodine uptake (1.6%). Serum thyrotropin receptor antibody (TRAb) was negative (0%) and she had positive anti-thyroglobulin and anti-microsomal antibodies. A diagnosis of silent thyroiditis was made based on laboratory findings. Serum concentrations of FT3 and FT4 normalized one month later without treatment. The causal relationship between the two diseases is discussed.


A marked molecular heterogeneity of growth hormone (GH) detected in the plasma but not pituitary of a patient with acromegaly: comparison with other acromegalics and an implication for discrepant plasma levels of GH and insulin-like growth factor. We experienced a 41-year-old acromegalic male (Case 1) in whom the basal plasma GH was extremely high (320-450 ng/mL) but plasma IGF-I was only slightly elevated (2.0-2.8 U/mL). His nutritional condition and associated diabetes mellitus did not appear to be responsible for the relatively low IGF-I level, and a GH-autoantibody in the plasma was absent. We thus performed gel filtration analyses of his plasma and somatotroph adenoma to determine elution patterns of immunoreactive (IR) and receptor active (RA) GH. For comparison, the same studies were carried out on plasmas and somatotroph adenomas obtained from three other acromegalics (Cases 2-4) whose basal plasma GH and IGF-I levels were 22-45 ng/mL and 3.5-6.0 U/mL, respectively. IR GH in Case 1's plasma distributed over an extremely wide range keeping similar titers rather than showing three discernible components (big-big, big, and little GH) as did plasmas and adenomas from Cases 2-4. And, most of the IR GH in Case 1's plasma was eluted in such fractions that contained low levels of RA GH, indicating a minor proportion of biologically active GH. However, interestingly, the chromatographic profile and total GH content of Case 1's adenoma were similar to those of Cases 2-4's adenomas. These results may, at least in part, explain the discrepancy between the plasma GH and IGF-I levels of Case 1. The unexpectedly different GH elution patterns between the plasma and adenoma from this patient, may suggest a contribution of certain plasma factor(s) to the unusual chromatographic profile of plasma GH.


Effect of progesterone supplementation in repeat-breeder cattle on conception and plasma progesterone. Reposital-type progesterone (75 mg/d for cows, 40 mg/d for heifers) or saline were administered to 24 Holstein cattle to assess the effects of exogenous progesterone (P) on fertility in repeat-breeders. Treatments were administered daily from day 6 to 10 after fourth, fifth and sixth insemination. Cumulative conception rate (57.1%) for the fourth through sixth insemination was affected by lactation number, service number, plasma P (4.67 ng/ml for pregnant cows vs 4.06 ng/ml for nonpregnant cows) and corpus luteum size on days 5 and 15. Plasma P concentrations were affected by day of cycle and size of corpus luteum on both ovaries on day 15. A treatment by day interaction accounted for higher plasma P in P-treated cattle than saline-treated cattle from day 5 through 15. Administration of exogenous P during early life of the corpus luteum in the repeat-breeder increased plasma P. Higher plasma P was associated with insemination success.


Quantitative studies on fatty acid metabolism in isolated parenchymal cells from normal and cirrhotic livers in rats. Parenchymal cells isolated from normal and thioacetamide-induced micronodular cirrhotic rat livers were used to evaluate changes in hepatocellular fatty acid (FA) metabolism in cirrhosis. Exogenous free FA (FFA) are rapidly taken up by hepatocytes obtained either from normal or cirrhotic livers. They are predominantly esterified to triglycerides and accumulate intracytoplasmatically as lipid droplets with increasing cellular FFA uptake. In the parenchymal cells of cirrhotic livers, however, the following changes were observed when compared with controls: (i) decreased cellular output of esterified FA derived both from exogenous sources and from de novo FA synthesis; (ii) increased total ketone body production, mainly as beta-hydroxybutyrate; (iii) decreased cholesterol synthesis; and (iv) enhanced incorporation of newly synthesized FA into phospholipids in spite of an unaffected rate of FA synthesis. In summary, the data provide evidence for intrinsic alterations in the lipid metabolism in the parenchymal cells of cirrhotic livers which are preserved in the isolated hepatocytes under optimum incubation conditions for oxygen and substrate supply.


Comparative effects of epidermal growth factor, an insulin-glucagon combination, and a hepatocyte growth factor preparation on epidermal growth factor receptors. We investigated the changes in cell surface epidermal growth factor (EGF) receptors in the liver after partial hepatectomy, and in primary adult rat hepatocyte cultures following stimulation with either EGF, or a preparation of hepatocyte growth factor, or an insulin-glucagon combination. We confirmed a reduction in EGF receptors on hepatocytes after partial hepatectomy and a rapid down-regulation of EGF receptors on normal hepatocytes in vitro following exposure to EGF. Insulin and glucagon and hepatocyte growth factor, whilst initiating hepatocyte DNA synthesis, had only slight effects on their EGF binding capacity and EGF-receptor affinity. These results indicate that changes in cell membranes early in proliferation have only non-specific effects on EGF receptors, and, therefore, support the role of ligand binding to the EGF receptor as an important component of hepatocyte proliferation in vivo.