Dysrhythmia, dysphoria, and depression: The interaction of learned helplessness and circadian dysrhythmia in the pathogenesis of depression.

Increasing evidence suggests that endogenomorphic depressions involve a disruption of circadian rhythms. We review this evidence in relation to comparable findings in animal helplessness studies. We examine the neurophysiological, neuropsychological, and nosological implications of such findings for both helplessness and depression. A disruption of circadian rhythms provides a framework, which suggests three sets of possible interactions between psychology and biology in the pathogenesis of helplessness and endogenomorphic depressions. First, it offers a mechanism to account for the role of life events in the precipitation of such depressions. Second, it provides a potent stimulus to the generation of the misattributions typical of depression and helplessness. Third, it provides a stress to which certain personalities may be particularly vulnerable. We discuss the theoretical, research, and remedial implications of these interactions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

LTP, NMDA, genes and learning

PURPOSE: To describe the results of strabismus surgery on three patients with chronic progressive external ophthalmoplegia, a group of rare disorders characterized by ptosis and slowly progressive ophthalmoparesis that has been shown to result from defects in mitochondrial DNA. METHODS: Strabismus surgery using the adjustable suture technique was performed in three patients with strabismus and chronic progressive external ophthalmoplegia confirmed by clinical, biochemical, histopathologic, and genetic criteria. All three patients had mitochondrial DNA deletions. Two patients were exotropic; one patient was esotropic. RESULTS: Rectus muscle recessions were initially unsuccessful in correcting strabismus in one patient, although a subsequent procedure employing rectus muscle resections was successful in alleviating a significant head turn and improved ocular alignment. In the two other patients, a single procedure consisting of rectus muscle recessions combined with large rectus muscle resections successfully achieved good postoperative alignment. The amount of surgery performed in these three patients exceeded that predicted in standard strabismus tables. CONCLUSIONS: The myopathic process that results in chronic progressive external ophthalmoplegia renders rectus muscle recessions less effective compared with resections for correcting the associated strabismus seen in these patients. Rectus muscle resections therefore should be an integral procedure in the surgical management of the strabismus associated with chronic progressive external ophthalmoplegia.     

Ciliary neurotrophic factor null allele frequencies in schizophrenia, affective disorders, and Alzheimer''s disease

The membrane assembly of outer membrane proteins is more complex than that of transmembrane helical proteins owing to the intervention of many charged and polar residues in the membrane. Accordingly, the predictive accuracy of transmembrane beta strands is considerably lower than that of transmembrane alpha helices. In this paper we develop a set of conformational parameters for membrane spanning beta strands. We formulate an algorithm to predict the transmembrane beta strands in the family of bacterial porins based on the conformational parameters and surrounding hydrophobicities of amino acid residues. A Fortran program has been developed which takes the amino acid sequence as the input file and gives the predicted transmembrane beta strand as output. The present method predicts at an accuracy level of 82% for all the bacterial porins considered.     

Dietary fatty acids modulate hormone responses in lactating cows: mechanistic role for 5''-deiodinase activity in tissue

Eight Salmonella typhimurium (Copenhagen) and eight Salmonella dublin isolates from cattle were compared by their antibiotic resistance patterns, by their production of colicin, aerobactin, haemolysin and capsule, by their possession of transmissible R plasmids and the spvC gene, and by their ability to invade and replicate within cultured epithelial cells. The two groups differed in their antibiotic resistance profiles, with more of the host-adapted S. dublin isolates resistant to tetracycline than were the non-host-adapted S. typhimurium (Copenhagen) group, but more of the S. typhimurium (Copenhagen) isolates resistant to the other antibiotics tested. None of the isolates produced colicin, but all produced aerobactin. One isolate in each group was encapsulated. All of the S. typhimurium (Copenhagen) and S. dublin isolates contained plasmids, and all of them contained the spvC-homologous sequences. Four of the S. typhimurium (Copenhagen) isolates were able to transfer an R plasmid to a recipient organism by conjugation. One of the five S. dublin isolates, which showed resistance to some of the antibiotics tested, was able to transfer an R plasmid by conjugation. Both groups of isolates invaded cultured epithelial cells to a similar degree after 1 h, but the S. dublin isolates reached significantly higher levels within the cells than did S. typhimurium (Copenhagen) after 9 h. This ability may, in part, explain the association of S. dublin with more severe forms of salmonellosis and prolonged carrier states. Further study of the intracellular growth of these isolates seems warranted.     

The potential for increased sparing of normal tissue in parallel opposed techniques with a multileaf collimator

A multileaf collimator (MLC) can be used in parallel opposed techniques as a direct replacement for standard-shaped beam blocks. However, improved shielding is possible if the MLC field is designed to fit a target rather than to mimic a straight-edged block. This study has compared the treatment areas produced by the MLC and by conventionally blocked fields with the target area for 43 parallel opposed treatments. It was found in every case that the MLC treated less than 10% excess tissue, and, in over 70% of patients, the excess was less than 5%. The conventional fields, however, treated more than 10% excess tissue in 70% of patients. The effect of MLC orientation and the benefits of using an MLC are discussed.     

Cumulative pregnancy and live birth rates after gamete intra-Fallopian transfer

To evaluate the efficacy of gamete intra-Fallopian transfer (GIFT) the Kaplan-Meier life table method was used to analyse a patient cohort treated with GIFT between 1991 and 1994. In a tertiary referral centre for reproductive medicine, 1628 women with a median age of 33 years and various causes of infertility were included to calculate cumulative pregnancy and live birth rates. Age and cause of infertility were main factor variables and the study was based on a total of 2941 consecutive GIFT cycles, leading to a first clinical pregnancy, and 3052 cycles, leading to a first live birth. The cumulative pregnancy and live birth rates were 49.6 and 38.8% respectively, after three initiated cycles and 64.1 and 52.0% respectively, after five initiated cycles. The multiple pregnancy rate was 22.6%. The implantation rate of 13.1% after GIFT demonstrates that the developing embryo benefits from a period of exposure within the environment of the Fallopian tube. The present results indicate that approximately 50% of couples will have at least one live baby after five initiated GIFT cycles. Advancing age was a major negative prognostic factor for the cumulative live birth rate because of higher cancellation rates, lower implantation rates and higher pregnancy failure rates.     

Dietary protein, urea nitrogen appearance and total nitrogen appearance in chronic renal failure and CAPD patients

This study was carried out to examine the mathematical relationships between the urea nitrogen appearance (UNA), total nitrogen appearance (TNA) and dietary nitrogen intake (DNI) in patients with chronic renal failure. Studies were conducted in 20 nondialyzed patients with advanced chronic renal failure (CRF) who were fed 27 constant protein diets for 24.8 +/- 9.5 days (SD) and eight patients undergoing continuous ambulatory peritoneal dialysis (CAPD), who ingested 13 constant protein diets for 20.3 +/- 4.9 days. All patients lived in a hospital research ward throughout the study and underwent full nitrogen balance measurements. Data were analyzed after patients attained equilibrium or near equilibrium with each dietary protein intake. In the CRF patients, using the mean values obtained during the equilibrium phase, there was a direct and precise correlation between the TNA and UNA, where TNA g/day = 1.19 UNA g/day + 1.27 g/day, r = 0.948. The correlation between DNI and UNA was also highly significant, but less precise, with somewhat greater 95% confidence intervals: DNI g/day = 1.20 UNA g/day + 1.74 g/day, r = 0.865. The relationship between DNI and TNA was not much more precise: DNI g/day = 0.97 TNA g/day + 0.65 g/day, r = 0.880. With the CAPD patients, the relationships were as follows: TNA g/day = 0.94 UNA g/day + 5.54 g/day, r = 0.956; DNI g/day = 0.97 UNA g/day + 6.80 g/day, r = 0.705; DNI g/day = 1.07 TNA g/day + 0.63 g/day, r = 0.760. For the CAPD patients, the lowest 95% confidence intervals were also found for the correlation between TNA and UNA. Thus, in both CRF and CAPD patients, the TNA is highly and precisely correlated with the UNA. The DNI is also significantly correlated with UNA and TNA, but the relationship is less precise. In both of these two groups of patients, the difference between the regression equations for TNA versus UNA and DNI versus UNA was, to a substantial degree, accounted for by the intercept.     

Atrial fibrillation: a review of pathophysiology

Atrial fibrillation is the most common sustained tachyarrhythmia and, as such, has become the recent focus of intense clinical and experimental interest. Because of its associated morbidity and mortality, there is a multidisciplinary effort to understand the pathophysiology that may ultimately lead to improved therapeutic options.     

Strategies to promote the use of advance directives in a residency outpatient practice

OBJECTIVE: To evaluate patient education and resident education strategies to promote advance directives in the outpatient setting, and to assess barriers to implementation. DESIGN: Controlled clinical trial. SETTING: The internal medicine residents' practice of an urban, university medical center. PATIENTS/PARTICIPANTS: Medical residents and 250 patients seen at least twice in the 3 months prior to the study. INTERVENTIONS: We randomized practice days: one to patient education, one to resident education, and three controls. Resident education consisted of a lecture, a videotape of a model advance directives discussion, and videotaping of an actual discussion by each resident, followed by individual review. Patient education consisted of distributing pamphlets in the waiting room and offering all patients an opportunity to discuss advance directives. MEASUREMENTS AND MAIN RESULTS: We interviewed 187 of these patients (response rate 75%) and surveyed 62 residents (response rate 70%). After 18 months, there were no significant differences in the number of advance directives in charts among the three groups. Documented advance directives discussions with patients in the resident education group increased from 3% to 17% (p < .001), more than those in the patient education (5%) or control group (10%, p = .04). Residents in the resident education group were more likely to report discussing advance directives than those in the patient education or control groups (p = .05). Lack of time (95%) and lack of continuity (76%) were the most frequently cited barriers. In multivariate logistic regression, nonwhite race and non-U.S. birth were negatively associated with patient interest in advance directives. Patient race and birthplace were not associated with actual discussions of advance directives. CONCLUSIONS: Even with intensive efforts to educate outpatients and residents about advance directives, important barriers remain, raising questions about how best to promote advance directives among outpatients.     

Cerebral blood flow as a predictor of outcome following traumatic brain injury

As part of a prospective study of the cerebrovascular effects of head injury, 54 moderate and severely injured patients underwent 184 133Xe-cerebral blood flow (CBF) studies to determine the relationship between the period of maximum blood flow and outcome. The lowest blood flows were observed on the day of injury (Day 0) and the highest CBFs were documented on postinjury Days 1 to 5. Patients were divided into three groups based on CBF values obtained during this period of maximum flow: Group 1 (seven patients), CBF less than 33 ml/100 g/minute on all determinations; Group 2 (13 patients), CBF both less than and greater than or equal to 33 ml/100 g/minute; and Group 3 (34 patients), CBF greater than or equal to 33 ml/100 g/minute on all measurements. For Groups 1, 2, and 3, mean CBF during Days 1 to 5 postinjury was 25.7 +/- 4, 36.5 +/- 4.2, and 49.4 +/- 9.3 ml/100 g/minute, respectively, and PaCO2 at the time of the CBF study was 31.4 +/- 6, 32.7 +/- 2.9, and 33.4 +/- 4.7 mm Hg, respectively. There were significant differences across Groups 1, 2, and 3 regarding mean age, percentage of individuals younger than 35 years of age (42.9%, 23.1%, and 76.5%, respectively), incidence of patients requiring evacuation of intradural hematomas (57.1%, 38.5%, and 17.6%, respectively) and incidence of abnormal pupils (57.1%, 61.5%, and 32.4%, respectively). Favorable neurological outcome at 6 months postinjury in Groups 1, 2, and 3 was 0%, 46.2%, and 58.8%, respectively (p < 0.05). Further analysis of patients in Group 3 revealed that of 14 with poor outcomes, six had one or more episodes of hyperemia-associated intracranial hypertension (simultaneous CBF > 55 ml/100 g/minute and ICP > 20 mm Hg). These six patients were unique in having the highest CBFs for postinjury Days 1 to 5 (mean 59.8 ml/100 g/minute) and the most severe degree of intracranial hypertension and reduced cerebral perfusion pressure (p < 0.0001). These results indicate that a phasic elevation in CBF acutely after head injury is a necessary condition for achieving functional recovery. It is postulated that for the majority of patients, this rise in blood flow results from an increase in metabolic demands in the setting of intact vasoreactivity. In a minority of individuals, however, the constellation of supranormal CBF, severe intracranial hypertension, and poor outcome indicates a state of grossly impaired vasoreactivity with uncoupling between blood flow and metabolism.