Biomedical subjects
Publications and source records attributed to M S Bauer.
A 7-year-old spayed female Doberman Pinscher had a fluctuant red mass that filled the entire crypt of the left palatine tonsil. The mass was surgically excised and was found to be a tonsillar cyst on histologic examination. Because the cyst was lined with pseudostratified epithelium, embryonic origin was the most probable etiopathogenesis.
37 outpatients with at least one prospectively observed manic or hypomanic episode comprised a sample for comparison of five definitions of dysphoric (hypo)mania. Dysphoric symptoms were continuously rather than bimodally distributed. Prevalence of dysphoria varied from 5 to 73% depending on the definition used. Female gender was associated with dysphoria under two of the five definitions. Inter-episode stability in patients with at least two prospectively observed episodes (n = 15) was not significantly different from chance. These data do not indicate that (hypo)mania can be dichotomized on the basis of dysphoria. Advantages and disadvantages of dimensional and categorical approaches to specifying mood in mania or hypomania are discussed.
OBJECTIVE: The validity of rapid cycling as a distinct course modifier for bipolar disorder was assessed by comparing patients with and without a history of rapid cycling (4 or more affective episodes in 12 months) on demographic, clinical, family history, and outcome variables. These data were also used to formulate operational criteria for the modifier. METHOD: Data on subjects with rapid-cycling (N = 120) and nonrapid-cycling (N = 119) bipolar disorder from four sites were pooled and analyzed by using case-control and historical cohort methods. RESULTS: The rapid-cycling group contained more women and more subjects from higher social classes than the nonrapid-cycling group. Family history did not differ between the groups. The diagnosis had predictive validity in that the rapid-cycling patients had more episodes than the nonrapid-cycling patients during prospective follow-up. The relationship between gender and episode frequency supported the validity of the cutoff point of 4-8 episodes per year. The data regarding whether patients with rapid cycling based on truncated episodes more closely resembled rapid-cycling or nonrapid-cycling patients were equivocal. Patients whose only rapid cycling was associated with antidepressants resembled spontaneously rapid-cycling patients, while the majority of spontaneously rapid-cycling patients also had periods of antidepressant-associated rapid cycling. CONCLUSIONS: The validity of rapid cycling as a distinct course modifier for bipolar disorder is supported by differences in gender, prospectively assessed outcome, and perhaps social class between rapid-cycling and nonrapid-cycling patients. The relationship of gender to episode frequency supports the cutoff of 4 or more episodes per year.
Sleep deprivation and fragmentation occurring in the hospital setting may have a negative impact on the respiratory system by decreasing respiratory muscle function and ventilatory response to CO2. Sleep deprivation in a patient with respiratory failure may, therefore, impair recovery and weaning from mechanical ventilation. We postulate that light, sound, and interruption levels in a weaning unit are major factors resulting in sleep disorders and possibly circadian rhythm disruption. As an initial test of this hypothesis, we sampled interruption levels and continuously monitored light and sound levels for a minimum of seven consecutive days in a medical ICU, a multiple bed respiratory care unit (RCU) room, a single-bed RCU room, and a private room. Light levels in all areas maintained a day-night rhythm, with peak levels dependent on window orientation and shading. Peak sound levels were extremely high in all areas representing values significantly higher than those recommended by the Environmental Protection Agency as acceptable for a hospital environment. The number of sound peaks greater than 80 decibels, which may result in sleep arousals, was especially high in the intensive and respiratory care areas, but did show a day-night rhythm in all settings. Patient interruptions tended to be erratic, leaving little time for condensed sleep. We conclude that the potential for environmentally induced sleep disruption is high in all areas, but especially high in the intensive and respiratory care areas where the negative consequences may be the most severe.
A questionnaire, designed to gather information regarding the use of live animals, cadavers, inanimate models, and other innovative methods to teach veterinary surgery, was mailed to individuals in the surgery sections of all 31 veterinary schools in the United States and Canada. Of the 31 questionnaires mailed, 27 (87%) were completed and returned. Mean number of total, general, small-animal, and large-animal surgery laboratory sessions were 22, 5.9, 11, and 7.4, respectively. At 7 of 26 (27%) schools, animals were euthanatized prior to recovery from anesthesia in all teaching laboratories; in 18 schools (69%), small animals were euthanatized prior to recovery from anesthesia. In 4 (20%) of the 20 schools that offer large-animal laboratory courses, large animals were euthanatized prior to recovery from anesthesia. In 24 schools (88%), cadavers, models, or both were used in at least 1 laboratory session in their surgery training program. Models were used most frequently to teach suturing, knot typing, and hemostasis. Plastic bones were used in 8 (30%) schools to teach fracture repair. In several schools, models were used to teach other general psychomotor skills, and at several schools, models were available for sale to other teaching institutions. At 16 (59%) of the 27 veterinary schools, some type of program has been developed with local humane societies. At 13 (81%) of the 16 schools with such a program, small animals were euthanatized prior to recovery from anesthesia in their traditional laboratories. At 10 (37%) of the schools, some process was used to evaluate students in the laboratory, and at 5 (19%), course evaluations were completed by students taking the laboratory.(ABSTRACT TRUNCATED AT 250 WORDS)
Thyroid function in patients in a current major depressive episode during the course of recurrent major mood disorder with seasonal pattern according to DSM-IIIR was compared to that of controls before and after 4 weeks' light treatment, and to that of controls at baseline and after 4 weeks' of arising early without exposure to bright light. No consistent abnormalities in thyroxine, free thyroxine index, triiodothyronine, reverse triiodothyronine, thyrotropin, thyrotropin response to TRH infusion, or thyroid autoantibodies were seen in depressives at baseline. No differences in these parameters were seen at baseline between depressives and controls. No intergroup differences were seen with treatment, although reverse T3 decreased significantly during the protocol in all groups. These data do not support the hypothesis that the thyroid axis plays a role in the pathogenesis of winter depressive symptoms or their response to light treatment.
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There is evidence that the risk for recurrence increases with each additional mood episode. Substantial data show that the probability of relapse and recurrence in both unipolar and bipolar disorders can be decreased by extended pharmacologic treatment. In recommending prolonged treatment to prevent recurrence, however, the values of each patient need to be considered, along with the age of onset, the meaning of each mood episode, its severity, and the clinical and social circumstances. Several questions remain to be answered. For instance, are there characteristics of first-episode unipolar or bipolar patients that will indicate whether extended treatment will prevent the next episode? How long should treatment be continued, and at what dose? Given the variety of treatments available for mood disorders, are there particular subsets of patients that are better suited or matched for one agent as opposed to another? What are the characteristics of bipolar patients whose depressive episodes can be treated safely with antidepressants, without risk of switching to mania? What are the costs and benefits of extended treatment, not only in terms of side effects and health service utilization, but also in terms of whether the agents we use may actually worsen the subsequent course of illness? Further questions concern the role of psychotherapy in the continuation and maintenance treatment of recurrent mood disorders. Although few clinicians would advocate psychotherapy alone for treatment of unipolar and bipolar patients at high risk for relapse and recurrence, the specific role of psychotherapy remains to be evaluated. It will be important to determine whether structured psychotherapies can provide additional benefit in terms of both episode prevention and functional outcome. This latter issue is particularly important in view of the substantial social and occupational morbidity even in remitted unipolar and bipolar patients--morbidity which is clearly significant in terms of the overall costs of mental illness. Clearly, more work needs to be done. Even the best studies indicate that a substantial proportion of patients are not helped by current treatments.
Male rats made hypothyroid by administration of propylthiouracil plus sodium ipodate in drinking water were compared to controls in terms of period of circadian activity and temperature rhythms, amount of gross motor activity, and mean temperature. Animals were studied under entrainment, constant darkness (DD), and constant dim light (LL). There was no difference in the period of the circadian activity rhythm between groups in DD. However, hypothyroid rats showed significant blunting of the period-lengthening response to increasing ambient illumination. As expected, the period of the circadian temperature rhythm increased in controls with increasing ambient illumination. In contrast, the period of the circadian temperature rhythm in hypothyroid animals actually shortened under LL compared to DD. This blunting of the period-lengthening response to increasing ambient illumination of both activity and temperature rhythms in hypothyroid animals could not be explained by differences in activity level or mean temperature between the groups.
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External fixation is an effective method for stabilization of many mandibular fractures. Thorough physical examination and patient stabilization should be instituted before attending to the fractures and associated soft tissue trauma. Normal occlusion rather than perfect reduction is the goal of oral fracture repair. Loose teeth or teeth in the fracture should be removed, as should any avascular bone fragments. Soft tissue wounds should be treated as for any contaminated wound. Mucosal wounds are allowed to heal by second intention. Although prophylactic perioperative antibiotics are indicated, they are usually not needed postoperatively. The three basic types of external fixators described include the Kirschner-Ehmer splint, pins or screws and acrylic, and the biphase splint. All three types are relatively easy to apply, and the principles of their application are similar. A minimum of two pins or screws are placed percutaneously in each fragment, avoiding the mandibular canal. The Kirschner-Ehmer splint is more easily adjustable than the biphase splint or the pin-acrylic splint, which use acrylic connecting bars. The advantages of fixators that use acrylic bars are that the pins or screws need not all be in the same plane and that they are more lightweight than the Kirschner-Ehmer splint. The disadvantages of the biphase splint are its increased expense and its use being limited to larger dogs. External fixators are well tolerated by the animals, and postoperative care is minimal. Mandibular fractures are usually healed in 3 to 5 weeks, and the fixators can be removed with the animal under sedation.
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Behavioral, neuropharmacological, and molecular studies of light-induced phase shifting of rodent circadian rhythms evaluate carefully the phase dependence of light responsivity. However, much less information is available regarding the dependence of such effects on the duration and irradiance of the photic stimulus used. In this study, very brief (5-min) white light pulses of 50 microW/cm2 (175 lux) administered to hooded rats elicited unequivocal type-1 phase responsivity, without significant changes in period, and with phase shift variability comparable to that in studies using longer, higher intensity pulses. Irradiance dependence was demonstrated in the phase-delay, phase-advance, and crossover portions of the phase-response curve, with minimal phase shifting seen during the dead zone even at very high irradiance. These results indicate that maximal phase-shifting magnitude may be achieved with shorter, less intense photic stimuli than are often used in studies of the neural mechanisms involved in light responsivity of rat circadian rhythms.
Measurements of the lithium concentration in the occipital pole of the head and calf muscle of nine patients with bipolar disorder in remission were performed using in vivo lithium-7 nuclear magnetic resonance spectroscopy (7Li NMR). 7Li NMR measurements were performed on a 1-m-bore, 1.85-T, superconducting magnet supplemented with a multinuclear spectrometer, using 11.5-cm-diameter surface coils. The average lithium concentration in the occipital pole was 0.36 +/- 0.10 mEq/L, whereas in the muscle it was 0.50 +/- 0.17 mEq/L, both lower than the average serum lithium concentration (0.79 +/- 0.23 mEq/L). The average brain/serum lithium concentration ratio was 0.47 +/- 0.12 whereas the average muscle/serum lithium concentration ratio was 0.66 +/- 0.20. There was a positive correlation between the brain versus serum and brain versus muscle lithium concentrations. The hypothesis is advanced that the minimal effective concentration of brain lithium concentration for maintenance treatment of bipolar disorder is around 0.2-0.3 mEq/L.
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We report the reliability and validity of the Internal State Scale, a self-report instrument for the simultaneous assessment of severity of manic and depressive symptoms. The Internal State Scale consists of four empirically derived subscales: Activation, Well-Being, Perceived Conflict, and the Depression Index. All subscales had good internal consistency reliability. Activation subscale scores were significantly higher in manic patients than in depressed patients or control subjects, while Well-Being subscale scores were significantly lower and the Depression Index subscale scores were significantly higher in depressed patients than in the other two groups. Activation subscale scores were correlated specifically with clinician ratings of mania. Depression Index subscale scores were correlated specifically with clinician ratings of depression. Further evidence for the validity of the subscales of the Internal State Scale in reflecting manic or depressive symptoms came from discriminant function analysis in which these subscales assigned 88% of subjects to the correct diagnostic groups. In affectively ill patients who were studied in two or more mood states, Activation, Depression Index, and Well-Being subscale scores changed significantly in the predicted directions, while the same discriminant algorithm assigned 79% of mood states to the correct diagnostic category. Bimodal distribution of scores of manic patients on the Well-Being and Depression Index subscales substantiated earlier findings that euphoric mood is not an essential feature of mania. Based on findings from this and previous studies, the hypothesis is proposed that variables related to activation level, and not to mood state, constitute the core characteristics of the manic syndrome.
The major direct cutaneous vessels identified in the cat include the omocervical, thoracodorsal, deep circumflex iliac, and caudal superficial epigastric arteries. Axial pattern skin flaps based on the thoracodorsal and caudal superficial epigastric arteries have been developed in cats. Rotation of these flaps as islands allows skin coverage to the carpus and metatarsus, respectively. The thoracodorsal and caudal superficial epigastric flaps provide a practical, one-step option in the reconstruction of large skin defects involving the distal extremities of cats.
A Phase I trial of 4-aminopyridine (4-AP) was carried out in 39 dogs referred to the veterinary teaching hospital with naturally occurring traumatic paraplegia or paraparesis. The rationale for the study was provided by the observation that 4-AP restores conduction in demyelinated nerve fibers in experimental spinal cord injury. Most injuries (77%) resulted from degenerative disk disease, occurring at or near the thoracolumbar junction, and producing chronic, complete paraplegia. Neurological examination of each dog was recorded on videotape before and at intervals after administration of 4-AP. The drug was administered systemically in total doses between 0.5 and 1 mg/kg body weight. Three areas of neurological status changed significantly at 15-45 minutes following administration of 4-AP: (a) striking improvements in hindlimb placing occurred in 18 animals; (b) increased awareness of painful stimuli to the hindlimb in 10 animals; (c) partial recovery of the cutaneus trunci muscle reflex of the back skin in 9 animals. These effects reversed within a few hours of administration. Other animals (36%) showed no change in neurological signs except a slight enhancement of hindlimb reflex tone. Significant side effects were seen in 6 dogs receiving higher intravenous doses, with elevation of body temperature and apparent anxiety, leading to mild seizures in 3 of the animals. These seizures were controlled with diazepam. The results indicate that conduction block may contribute significantly to functional deficits in closed-cord injuries and that potassium channel blockade may prove to be a valid, if limited approach to therapeutic intervention in chronic paraplegia and paraparesis.