Increases in nocturnal bruxism among college students implicate stress.

While the etiology of nocturnal bruxism is unknown, three major categories of theories have been advanced to explain its cause(s), i.e., local-mechanical theories, psychological theories and systemic/neurophysiological theories. The recent report of a four-fold increase in the incidence of self-reported nocturnal bruxism in college students over the last 23-year period emphasizes the role that psychological variables may play in the development of this disorder and it is suggested that the personality traits which contribute to stress management are primary among these.

Changes in the incidence of nocturnal bruxism in college students: 1966-1989.

The frequency of self-reported nocturnal bruxism in three large samples of college undergraduates was compared as a means of assessing change in the incidence of this disorder since 1966. We found the incidence of nocturnal bruxism had increased from 5.1% to 20.5% in college students over the period covered by these studies.

Arousability and stress-related physical symptoms: a validation study of Coren's arousal predisposition scale.

Coren's Arousal Predisposition Scale was validated against 249 college students' self-ratings of stress-related physical symptoms and an item that assessed general level of health. As we predicted, the 126 high-arousability subjects were substantially higher in mean stress-related symptoms score and lower in general health than the 123 peers low in arousability. These data suggest that the Arousal Predisposition Scale may be a useful instrument in the study of human stress.

Coping with a major stressor: differences between habitual short- and longer-sleepers.

We compared the coping strategies of 39 short-sleepers and 33 longer-sleepers to the stresses associated with the October 17, 1989 San Francisco Bay Area earthquake using their responses to the eight scales of the Ways of Coping Questionnaire. Over-all, the short-sleepers scored significantly higher on this questionnaire and in general, the pattern of their responses was consistent with inferences that could be drawn from a 1972 paper by Hartmann, Baekeland, and Zwilling.

The incidence of sleep problems among type A and type B college students: changes over a ten-year period (1982-1992).

Ten years ago we reported that Type A scoring students were twice as likely as their Type B peers to report sleep problems. In an exact 1992 replication of that study, no Type A-B differences in the frequency of self-reported sleep problems were observed; however, the over-all incidence of sleep problems among the 753 college students had increased substantially.

VNA of Boston addresses cultural barriers in home-based care.

Home care professionals know that communication is the key to successful treatment. But what if the patient speaks a different language? One home care agency addresses this problem with a culturally diverse staff and access to interpretation services.

Liver wedge biopsy in chimpanzees (Pan troglodytes) using an automatic stapling device.

Liver wedge biopsies were taken from 10 chimpanzees using an automatic stapling instrument. The procedure provided sufficient quantities of liver tissue for cell culture, provided excellent hemostasis and reduced surgery time.

A gastric trichobezoar in a chimpanzee.

A firm, mobile, oblong mass was discovered as an incidental finding in the stomach of a chimpanzee (Pan troglodytes) during routine surgery. It was removed and determined to be a trichobezoar.

Immobilization of a chronic intravenous catheter in the saphenous vein of African green and rhesus monkeys.

Long-term immobilization of intravenous catheters in the saphenous vein of nonhuman primates was accomplished through the application of a lightweight fiberglass tape casting system developed for human orthopedic use. The advantages of this technique are that it (a) permits successful retention of superficial vein catheters, (b) eliminates the need for deep vessel surgical procedures when only blood collection or perfusion protocols are being implemented and (c) permits repeated use of a single preparation without maintaining the animal under rigid restraint.

Comparison of North American and European malignant hyperthermia group halothane contracture testing protocols in swine.

Different in vitro halothane testing procedures have been used in the European malignant hyperthermia (MH) Group Protocol (EMHGP) and the North American MH Group Protocol (NAMHGP), whereas the caffeine-testing protocols are very similar. The present study compares the two halothane-testing protocols in ten MH susceptible swine and in four control swine. Halothane contracture testing was conducted in vitro 12-52 days following the barnyard challenge that established the MH susceptibility of the swine. There was one false positive and one false negative halothane test by the EMHGP. The MH-equivocal category in the EMHGP, which is treated clinically as MH-susceptible, affords a margin of safety in such cases. In contrast, there were no false halothane tests by the NAMHGP. While some skeletal muscle strips from MH pigs were normal by both protocols (NAMHGP 30%; EMHGP 10%), the outcome of halothane testing by the NAMHGP was unaffected. The response to halothane 3% is reduced if preceded by the EMHGP, suggesting that simply adding halothane 3% to the end of the EMHGP does not permit a direct quantitative comparison to the NAMHGP. However, the diagnostic outcomes of the two approaches are similar.

Effect of cage size on patterns of activity and health of beagle dogs.

Thirty-two male beagle dogs were assigned at random, 16 to standard size cages (30 X 30 X 30 inches) and 16 to large cages (90 X 30 X 30 inches) for a period of 13 weeks, and then were "crossed-over" for an additional period of 13 weeks. The dogs were observed daily and weighed weekly. Electrocardiographic and ophthalmologic examinations were made once and hematologic and biochemical measurements were made twice during the control period and at monthly intervals during the study. Photographs were taken of each dog every 60 seconds, 7 days a week, for about 8.5 hours each day. The film was processed and analyzed for the acf standing sitting, lying, or sleeping. In addition, dogs in the large cages were scored for the region (front, middle, or back) occupied. No statistically significant differences were found between dogs in the standard or large cages with respect to weight gain, percent of time standing, and percent of time sleeping. Statistically significant (p less than 0.05) differences were found for percent of time sitting (standard cages 12.7%; large cages 9.4%) and percent of time lying (standard cages 6.6%; large cages 8.3%); however, the differences were not large enough to be of any practical concern. Transient patterns of response over 13-week periods of the study were essentially the same (statistically verified) for dogs in either size cage. Also statistical results showed that there was no significant carryover (residual) effect associated with any of the parameters measured. No beneficial or adverse effects were noted that could be related to the size of the two cages. The size of the standard cage appeared adequate for laboratory beagle dogs and no advantage was found when the dogs were in larger cages with respect to behavior, patterns of activity, or health.

Altered [3H]ryanodine binding is not associated with malignant hyperthermia susceptibility in terminal cisternae preparations from swine.

Based on comparisons between Pietrain malignant hyperthermia susceptible swine and Yorkshire control swine, other investigators have reported a 3-fold lower Kd for [3H]ryanodine binding to terminal cisternae in the malignant hyperthermia swine. However, the Kd of [3H]ryanodine binding did not correlate with malignant hyperthermia susceptibility when examined within the same strain (a Yorkshire/Duroc cross) in the present study. The values of Kd for the malignant hyperthermia susceptible and control swine in the present study were similar to those previously reported for the Pietrain strain, suggesting that the control strain chosen, not malignant hyperthermia susceptibility, accounts for what appeared to be a low Kd in Pietrain muscle.

Caffeine and halothane contracture testing in swine using the recommendations of the North American Malignant Hyperthermia Group.

Caffeine and halothane contracture testing is widely used to detect malignant hyperthermia (MH) susceptibility. The accuracy and reliability of the 3% halothane test and the incremental caffeine test, as recommended by the North American MH Group, were assessed in 11 swine (five MHS, six control). Nine swine were tested twice, 4-6 weeks apart. Accuracy of the in vitro diagnosis was also assessed by in vivo anesthetic challenge. Of all muscle bundles from MH-susceptible swine, 65% reacted positively to 3% halothane and 70% to 2 mM caffeine. Only 35% had a positive caffeine-specific concentration, and 25% developed an increase in baseline tension greater than or equal to 7% at 2 mM caffeine. However, when only the most positive response to 3% halothane or to 2 mM caffeine was used (a minimum of three fresh muscle strips is recommended), these two tests were highly sensitive and specific. In control swine one of 30 muscle bundles reacted positively to 3% halothane. A positive caffeine-specific concentration developed in one of 25 control muscle bundles exposed to caffeine. The variability in the results of these tests mandated that at least three muscle bundles be used for each test. Nonviable muscle bundles could not be relied upon to provide accurate results. In this porcine model, MH susceptibility could be detected by performing the Caffeine Halothane Contracture Test (CHCT) according to the guidelines of the North American MH Group. However, only the 3% halothane test and the response to 2 mM caffeine produced adequate diagnostic results in this breed of swine.

Cage activity in the laboratory beagle: a preliminary study to evaluate a method of comparing cage size to physical activity.

The use of time-lapse and normal speed photography as a tool in evaluating the effect of cage size on physical activity in the beagle dog was examined. Normal speed motion pictures also served to demonstrate the degree of physical activity possible within specific sized cages, and the effect of changes in external activity on the dogs' activity within the cage. Viewing of these films showed that specific activity measurements can be made, providing a feasible scientific method for evaluating cage activity in a wide range of cage sizes. Physiological data collected over the course of this experiment from dogs housed in 2 different sized cages failed to show a cause-and-effect relationship.

Fatty acids modulate calcium-induced calcium release from skeletal muscle heavy sarcoplasmic reticulum fractions: implications for malignant hyperthermia.

Based on studies in swine, the malignant hyperthermia syndrome has been postulated to result from an enhanced sensitivity (low threshold) of the Ca2(+)-induced Ca2(+)-release process. However, fatty acid production is elevated in homogenates of skeletal muscle from pigs and humans susceptible to malignant hyperthermia. In the present study, we demonstrate that the threshold of Ca2(+)-induced Ca2+ release is normal in susceptible humans and in susceptible swine depleted of triglycerides. Exogenously added unsaturated fatty acids decreased the threshold of Ca2(+)-induced Ca2+ release to a much greater extent in porcine and equine muscle than in human muscle. When triglyceride and free fatty acid values were reduced to about 40 and 60%, respectively, of control values, malignant hyperthermia-susceptible swine did not exhibit muscle rigidity when challenged in vivo with halothane and succinylcholine and the threshold of the Ca2(+)-induced Ca2(+)-release process in heavy sarcoplasmic reticulum fractions was normal. Despite the reduced triglyceride and fatty acid levels, these swine had a positive in vitro contracture test for malignant hyperthermia. A low Ca2(+)-induced Ca2(+)-release threshold is not essential for malignant hyperthermia susceptibility, but appears to be the result of excessive free fatty acids produced during organelle isolation.

Studies in chimpanzees of live, attenuated hepatitis A vaccine candidates.

Human hepatitis A virus was attenuated in virulence for chimpanzees by passage in FRhK6 and human diploid lung fibroblast cell cultures. A number of variants were developed by passage in cell cultures which showed different levels of virulence/attenuation for chimpanzees. These results were compared to those obtained with marmosets and reported previously. In general, most variants behaved similarly in the two animal types. Two chimpanzees which gave vaccine-like responses following inoculation with HAV cell culture variants were challenged with virulent HAV. Both animals were immune to HAV infection. These findings provide further evidence for the feasibility of developing live, attenuated vaccines against human hepatitis A.