Candidate genes and their interactions with other genetic/environmental risk factors in the etiology of schizophrenia.

Identification of causative factors for common, chronic disorders is a major focus of current human health science research. These disorders are likely to be caused by multiple etiological agents. Available evidence also suggests that interactions between the risk factors may explain some of their pathogenic effects. While progress in genomics and allied biological research has brought forth powerful analytic techniques, the predicted complexity poses daunting analytic challenges. The search for pathogenesis of schizophrenia shares most of these challenges. We have reviewed the analytic and logistic problems associated with the search for pathogenesis. Evidence for pathogenic interactions is presented for selected diseases and for schizophrenia. We end by suggesting 'recursive analyses' as a potential design to address these challenges. This scheme involves initial focused searches for interactions motivated by available evidence, typically involving identified individual risk factors, such as candidate gene variants. Putative interactions are tested rigorously for replication and for biological plausibility. Support for the interactions from statistical and functional analyses motivates a progressively larger array of interactants that are evaluated recursively. The risk explained by the interactions is assessed concurrently and further elaborate searches may be guided by the results of such analyses. By way of example, we summarize our ongoing analyses of dopaminergic polymorphisms, as well as infectious etiological factors in schizophrenia genesis.

Steroid-sparing effects of pentoxifylline in pulmonary sarcoidosis.

BACKGROUND: Agents that target pro-inflammatory cytokines may be useful in pulmonary sarcoidosis. OBJECTIVE: To determine effectiveness of a non-selective cyclic nucleotide phosphodiesterase (PDE) inhibitor, pentoxifylline (POF). DESIGN: Randomized, double-blind, placebo-controlled trial, SETTING: Clinical Research Center, National Institutes of Health. PATIENTS: 27 patients with biopsy-confirmed pulmonary sarcoidosis receiving prednisone. INTERVENTION: Placebo or POF (1200-2000 mg/day) for 10 months, as prednisone was tapered. MEASUREMENTS: Primary endpoints: sustained improvement in two or more pulmonary function parameters, or a combination of one pulmonary function parameter and dyspnea. RESULTS: Except for one patient, primary endpoints were not reached in POF-treated patients. Therefore, a post hoc analysis was performed. The observed relative risk reduction for flares associated with POF treatment was 54.9% (95% CI 0.21, 0.89) and the absolute risk reduction was 50.6% (95% CI 0.22, 0.80). Compared to placebo treatment, in the POF group, the mean prednisone dose was lower at 8 and 10 months (p = 0.007 and 0.01 respectively), and there was a trend towards less prednisone usage over the entire study period (p = 0.053), as determined by cumulative change analysis. CONCLUSIONS: Although our exploratory post hoc analysis suggested that POF reduced flares and had steroid-sparing effects, given the study limitations, definitive conclusions cannot be drawn regarding the efficacy of POF in pulmonary sarcoidosis. In addition, gastrointestinal side-effects, at the doses used, would seem to limit the use of POF in treating pulmonary sarcoidosis. Overall, however, this trial may provide a basis for using more specific, better-tolerated, PDE inhibitors in future clinical trials.

Mechanisms of sodium fluoride-induced endothelial cell barrier dysfunction: role of MLC phosphorylation.

NaF, a potent G protein activator and Ser/Thr phosphatase inhibitor, significantly increased albumin permeability and decreased transcellular electrical resistance (TER), indicating endothelial cell (EC) barrier impairment. EC barrier dysfunction induced by NaF was accompanied by the development of actin stress fibers, intercellular gap formation, and significant time-dependent increases in myosin light chain (MLC) phosphorylation. However, despite rapid, albeit transient, activation of Ca(2+)/calmodulin-dependent MLC kinase (MLCK), the specific MLCK inhibitor ML-7 failed to affect NaF-induced MLC phosphorylation, actin cytoskeletal rearrangement, and reductions in TER, suggesting a limited role of MLCK in NaF-induced EC activation. In contrast, strategies to reduce Rho (C3 exoenzyme or toxin B) or to inhibit Rho-associated kinase (Y-27632 or dominant/negative RhoK) dramatically reduced MLC phosphorylation and actin stress fiber formation and significantly attenuated NaF-induced EC barrier dysfunction. Consistent with this role for RhoK activity, NaF selectively inhibited myosin-specific phosphatase activity, whereas the total Ser/Thr phosphatase activity remained unchanged. These data strongly suggest that MLC phosphorylation, mediated primarily by RhoK, and not MLCK, participates in NaF-induced EC actin cytoskeletal changes and barrier dysfunction.

Magnetic resonance cholangiopancreatography (MRCP) in the assessment of pancreatic duct trauma and its sequelae: preliminary findings.

BACKGROUND: The purpose of this study was to determine the utility of magnetic resonance cholangiopancreatography (MRCP) in the evaluation of pancreatic duct trauma and pancreas-specific complications. METHODS: Ten hemodynamically stable patients with clinically suspected pancreatic injury related to blunt abdominal trauma (n = 8), penetrating trauma (n = 1), or iatrogenic trauma (n = 1) underwent MRCP. Two abdominal radiologists conducted a review of the MRCPs to assess for the presence or absence of pancreatic duct trauma and pancreas-specific complications such as pseudocysts. The MRCP findings were correlated with endoscopic retrograde cholangiopancreatograms (n = 2), surgical findings (n = 1), computed tomographic scans (n = 10), and with clinical, biochemical or imaging follow-up (n = 10). RESULTS: Diagnostic quality MRCPs were obtained in each of the 10 patients. A mean imaging time of 5 minutes was required to perform the MRCPs. Pancreatic duct injuries were detected in four patients; pseudocysts were detected in three of these four patients. The pancreatic duct injuries in three patients were acute or subacute. In one of the three patients, disruption of a side branch of the pancreatic duct diagnosed with MRCP was not detected with endoscopic retrograde cholangiopancreatography but was confirmed surgically. In the fourth patient, the pancreatic duct injury was chronic; MRCP revealed a posttraumatic stricture in this patient who had sustained blunt abdominal trauma 17 years previously. In the remaining six patients, pancreatic duct trauma was excluded with MRCP. The information derived from the MRCPs was used to guide clinical decision-making in all 10 patients. CONCLUSIONS: MRCP enables noninvasive detection and exclusion of pancreatic duct trauma and pancreas-specific complications and provides information that may be used to guide management decisions.

Shopping center wheelchair accessibility: ongoing advocacy to implement the Americans with Disabilities Act of 1990.

Although the regulations of the Americans with Disabilities Act (ADA) of 1990 were phased in by 1992, monitoring and enforcement continue to be problematic. This study of three large shopping centers in the Southwest included one mall that was opened in the mid-1990s, and two malls that were constructed prior to the law (but have undergone recent renovations). Use of the ADA Accessibility Guidelines Checklist for Buildings and Facilities (Architectural and Transportation Barriers Compliance Board [ATBCB], 1992) generated data which were analyzed descriptively to determine the frequency and percent compliance in: parking lots, entrances, ramps, elevators, telephones, restrooms, food courts, and 12 specific store-types. No mall was fully compliant in any area, other than telephone specifications. In other areas, compliance ranged from 0% (ramp slopes in the newer mall) to many areas of 100% compliance (for example, outdoor curb ramps and food court seating spaces and aisles). The implications are that shoppers who are wheelchair mobile cannot count on complete compliance and cannot predict which physical architectural barriers they will find in shopping centers.

Consumer empowerment through occupational therapy: the Americans With Disabilities Act Title III.

OBJECTIVE: The purpose of this study was to determine whether occupational therapists (a) value a role educating consumers about the Americans With Disabilities Act of 1990 (ADA; Public Law 101-336); (b) are knowledgeable regarding Title III of the ADA; and (c) implement provisions and empower consumers who use wheelchairs to access public accommodations. METHOD: A random sample of 510 occupational therapists was surveyed, with 229 responding. Of those surveys returned, 152 respondents who serve clients who use wheelchairs met inclusion criteria. RESULTS: Although 90% of the participants agreed that occupational therapists should have ADA knowledge and should educate consumers, the mean score of ADA accessibility knowledge on a 10-point quiz was 1.85. The mean score of reported actions to implement ADA provisions with clients was 11.78 of a possible 40 points. There was a significant positive correlation between implementation and attitude (r = .3609, p = .01) and between implementation and knowledge (r = .3376, p = .01); however, the correlation between attitude and knowledge (r = .1673, p = .05) was not significant. CONCLUSION: Therapists' lack of knowledge and their self-reported inaction with regard to ADA Title III may affect the accessibility of the environment, independence, and empowerment of clients who are wheelchair mobile and, therefore, may impede progress toward fully inclusive communities.

Salbutamol and the conditioning of latissimus dorsi for cardiomyoplasty.

BACKGROUND: Cardiomyoplasty is a new surgical alternative therapy for CHF. Although conditioning of muscle for cardiomyoplasty has a positive effect on fatigue resistance it also produces negative effects. In this study we assessed the effect of salbutamol, a beta2-agonist, on both the positive and the negative effects of conditioning. METHODS: In a control group of six animals one latissimus dorsi was subject to chronic, 1 Hz, low-frequency stimulation (CLFS) while the other served as a control. The experimental group of seven dogs received a continuous SC infusion of salbutamol and one latissimus dorsi was subjected to CLFS. The other muscle demonstrated the effects of salbutamol per se. After 42 days the animals were anesthetized and fatigue resistance, muscle mass, and mechanical properties of the muscles were evaluated. RESULTS: Salbutamol increased muscle mass, tetanic tension, and rate of rise and fall of tetanic tension. It diminished fatigue resistance and had no effect on shortening velocity. Chronic stimulation decreased muscle mass, tetanic tension, rate of rise and fall of tetanic tension, and muscle shortening velocity in both groups of dogs. Salbutamol diminished the declines in muscle mass, rate of tension development, and rate of muscle shortening due to CLFS, but did not change the effects of CLFS on tetanic tension and the rate of fall of tetanic tension. Salbutamol did not alter the increase in fatigue resistance induced by CLFS. CONCLUSIONS: The favorable effect of CLFS on fatigue resistance was unaffected by salbutamol. The unfavorable effects of CLFS on loss of muscle mass, rate of tension development, and decline in shortening velocity were partially blocked by salbutamol, improving the ability of the latissimus dorsi to augment cardiac systole.

Biochemical regulation of the nonmuscle myosin light chain kinase isoform in bovine endothelium.

Specific models of vascular permeability are critically dependent on myosin light chain phosphorylation, a reaction catalyzed by a novel high molecular-weight (214 kD) Ca2+/calmodulin (CaM)-dependent myosin light chain kinase (MLCK) isoform recently cloned in human endothelium (Am. J. Respir. Cell Mol. Biol., 1997;16:489-494). To evaluate mechanisms of endothelial cell (EC) barrier dysfunction evoked by the serine protease thrombin, we studied the regulation of the 214-kD EC MLCK isoform expressed in bovine endothelium. The EC MLCK isoform bound biotinylated CaM in a Ca2+-dependent manner and co-immunoprecipitated in a functional complex with myosin, actin, and CaM. Thrombin rapidly increased MLCK activity in concert with time-dependent translocation of the enzyme to the actin cytoskeleton. To evaluate whether EC MLCK activity was regulated by direct phosphorylation, amino acid sequence analysis identified multiple potential EC MLCK sites for Ser/Thr phosphorylation, including highly conserved phosphorylation sites for cyclic adenosine monophosphate-dependent protein kinase A (PKA) adjacent to the CaM-binding region. EC MLCK activity was attenuated by either PKA-mediated MLCK phosphorylation or inhibition of Ser/Thr phosphatase activity (fluoride or calyculin), which significantly increased MLCK phosphorylation while decreasing MLCK activity (3- to 4-fold decrease). In summary, although the EC MLCK isoform exhibits multiple features intrinsic to this family of kinases, thrombin-mediated EC contraction and barrier dysfunction requires increased EC MLCK-actin interaction and MLCK translocation to the cytoskeleton. EC MLCK activity appears to be highly dependent upon the phosphorylation status of this key contractile effector.

Afterload sensitivity of nonlinear end-systolic pressure-volume relation vs preload recruitable stroke work in conscious dogs.

The observations in vivo of a non-linear, afterload-sensitive end-systolic pressure-volume relation (ESPVR) and a linear, load-insensitive preload recruitable stroke work (PRSW) relation may be reconciled by considering the PRSW as a product of both the ventricular ESPVR and the arterial elastance (Ea). We obtained pressure-volume data from eight conscious dogs. The ESPVR was nonlinear, and its trajectory was afterload-dependent. The PRSW was linear and load-independent. Arterial elastance changed with both acute reductions in preload and steady-state changes in afterload. The PRSW relation thus describes both myocardial function and ventricular-arterial interaction and is a useful index of cardiovascular performance in patients.

Regulation of endothelial cell myosin light chain phosphorylation and permeability by vanadate.

The involvement of tyrosine protein phosphorylation in the regulation of endothelial cell (EC) contraction and barrier function is poorly understood. We have previously shown that myosin light chain (MLC) phosphorylation catalyzed by a novel 214 kDa EC myosin light chain kinase (MLCK) isoform is a key event in EC contraction and barrier dysfunction [Garcia et al. (1995): J Cell Physiol 163:510-522; Garcia et al. (1997): Am J Respir Cell Mol Biol 16:487-491]. In this study, we tested the hypothesis that tyrosine phosphatases participate in the regulation of EC contraction and barrier function via modulation of MLCK activity. The tyrosine phosphatase inhibitor, sodium orthovanadate (vanadate), significantly decreased electrical resistance across bovine EC monolayers and increased albumin permeability consistent with EC barrier impairment. Vanadate significantly increased EC MLC phosphorylation in a time-dependent manner (maximal increase observed at 10 min) and augmented both the MLC phosphorylation and permeability responses produced by thrombin, an agonist which rapidly increases tyrosine kinase activities. The vanadate-mediated increase in MLC phosphorylation was not associated with alterations in either phosphorylase A Ser/Thr phosphatase activities or in cytosolic [Ca2+] but was strongly associated with significant increases in EC MLCK phosphotyrosine content. These data suggest that tyrosine phosphatase activities may participate in EC contractile and barrier responses via the regulation of the tyrosine phosphorylation status of EC MLCK.

Pseudomembraneous clostridium after autologous bone marrow transplantation.

Clostridium difficile (C. difficile) pseudomembraneous colitis was diagnosed in a 13-year-old boy with Hodgkin's disease 3 months after autologous bone marrow transplantation. Hematopoiesis was fully reconstituted at the time. C. difficile infection occurred after gall bladder empyema had been treated conservatively with i.v. antibiotics and prophylactic 4-week administration of oral amoxicillin. C. difficile colitis was diagnosed early and intensive supportive therapy combined with administration of i.v. and subsequently oral vancomycin therapy failed. It is a phenomenon rarely seen and successful eradication of the clostridium infection was only achieved by a combination of higher dose vancomycin with metronidazole. During the post-colitis recovery the patient experienced a relapse of Hodgkin's disease and died following further surgical intervention 137 days post-transplantation.

Role of tyrosine phosphorylation in thrombin-induced endothelial cell contraction and barrier function.

Thrombin-induced endothelial cell (EC) barrier dysfunction is highly dependent upon phosphorylation of serine and threonine residues present on myosin light chains (MLC) catalyzed by a novel EC myosin light chain kinase (MLCK) isoform. In this study, we examined the participation of tyrosine protein phosphorylation in EC contraction, gap formation and barrier dysfunction. We first determined that thrombin significantly increases protein tyrosine kinase activity and protein tyrosine phosphorylation in bovine pulmonary artery EC. Tyrosine kinase inhibitors, genistein and 2,5 DHC, reduced EC tyrosine kinase activities, however, only genistein significantly attenuated thrombin-mediated increases in albumin clearance and reductions in transendothelial electrical resistance. Similarly, genistein but not 2,5 DHC, decreased basal and thrombin-induced Ca2+ increases and MLC phosphorylation in the absence of alterations in Type 1 or 2A serine/threonine phosphatase activities. Immunoprecipitation of the EC MLCK isoform revealed a 214 kD immunoreactive phosphotyrosine protein and genistein pretreatment significantly reduced MLCK activity in MLCK immunoprecipitates. Although thrombin induced the translocation of p60src from the cytosol to the EC cytoskeleton, a detectable increase in the level of MLCK tyrosine phosphorylation was not noted after thrombin challenge. Taken together, our data suggest that genistein-sensitive tyrosine kinase activities are involved in thrombin-mediated EC MLCK activation, MLC phosphorylation, and barrier dysfunction.

Myocardial oxygen consumption in the rabbit heart after ischemia: hyperpolarized arrest with pinacidil versus depolarized hyperkalemic arrest.

BACKGROUND: This study was designed to test the hypothesis that adenosine triphosphate-sensitive potassium channel opener (PCO)-induced hyperpolarized arrest with pinacidil minimizes cellular energy requirements during global ischemia compared with traditional, hyperkalemic depolarized arrest, which is known to be associated with ongoing energy-consuming ion transport. METHODS AND RESULTS: Using a blood-perfused parabiotic rabbit heart Langendorff model, myocardial oxygen consumption (MVO2) was compared in hearts protected with either Krebs-Henseleit solution (K-H), pinacidil (50 micromol/L in K-H), or hyperkalemic St. Thomas' solution during a 30-minute period of global, normothermic (37 degrees C) ischemia followed by 30 minutes of reperfusion. MVO2 (mL/100 g of myocardium per beat) was calculated at baseline and continuously during reperfusion with the use of an in-line flow probe and an in-line coronary sinus oximetric catheterizationeter. Systolic function (percentage recovery of developed pressure) was measured over a range of volumes using a balloon in the left ventricle. Percentage recovery of developed pressure with pinacidil (60.3%+/-3.1%) was not statistically different from that with St Thomas' solution (53.3%+/-2.8%). Pinacidil provided superior protection versus K-H (44.4%+/-4.8%, P<.05). The MVO2 was significantly (P<.05) elevated in the pinacidil group (0.77+/-0.12) compared with the St Thomas group (0.29+/-0.04) during the first 6 minutes of reperfusion. CONCLUSIONS: The cardioprotective properties of PCOs are associated with an increased myocardial oxygen demand on reperfusion. This may be related to reparative processes of viable myocytes or to a higher oxygen debt generated during ischemia that presents a significant limitation to PCO cardioplegia.

Myosin light chain kinase in endothelium: molecular cloning and regulation.

The phosphorylation of myosin light chains by myosin light chain kinase (MLCK) is a key event in agonist-mediated endothelial cell gap formation and vascular permeability. We now report the cloning and expression of a nonmuscle MLCK isoform in cultured endothelium. Screening of a human endothelial cell cDNA library identified a 7.7 kb cDNA with substantial (> 95%) homology to the coding region of the rabbit and bovine smooth muscle (SM) MLCK (amino acid #923-1913) as well as with the reported avian nonmuscle MLCK (65-70% homology). Sequence analysis also identified, however, a 5' stretch of novel sequence (amino acids #1-922) which is not contained in the open reading frame of mammalian SM MLCK, and is only 58% homologous to the avian fibroblast MLCK sequence. Immunoprecipitation with NH2-specific antisera revealed a 214 kD high molecular weight MLCK in bovine and human endothelium which exhibits MLC phosphorylation properties. Amino acid sequence analysis revealed endothelial MLCK consensus sequences for a variety of protein kinases including highly conserved potential phosphorylation sites for cAMP-dependent protein kinase A (PKA) in the CaM-binding region. Augmentation of intracellular cAMP levels markedly enhanced MLCK phosphorylation (2.5-fold increase) and reduced kinase activity in MLCK immunoprecipitates (4-fold decrease). These data suggest potentially novel mechanisms of endothelial cell contraction and barrier regulation.

Job descriptions and performance appraisals: perceptions of staff occupational therapists and their supervisors.

OBJECTIVES: The purpose of this study was to survey pediatric hospital-based staff occupational therapists and their supervisors to determine if they are satisfied when accurate staff job descriptions are reflected in the staff performance appraisals. METHODS: Satisfaction Surveys were completed by 22 sets of staff occupational therapists and their supervisors. The supervisors also completed Department Surveys for demographic information. Correlational and t-test analyses were completed. Descriptive information was also reported. RESULTS: Both staff occupational therapists and supervisors appear generally satisfied with the job descriptions and performance appraisals they utilize. Only staff therapists' responses were found to indicate relationships between job description accuracy and performance appraisal satisfaction and job description-performance appraisal correspondence and satisfaction with the performance appraisal. CONCLUSION: Staff satisfaction with job descriptions and performance appraisals was high. Data regarding content of these documents may provide useful information to department directors who wish to revise their documents and increase employee satisfaction.

A review of selected school-based conflict resolution and peer mediation projects.

Many U.S. schools are implementing curricula and other activities to reduce interpersonal violence among students. Most involve conflict resolution or peer mediation (CR/PM) training. Little is known about the effectiveness or manner of implementing these projects. This paper examines nine projects supported by four state health departments. Available data suggest some projects may modify youths' self-reported attitudes about violent behavior, improve school discipline, and reduce absenteeism. The review also revealed considerable variation in implementation, especially in the role of professionally trained consultants and amount of teacher and student training. More attention should be paid to evaluating CR/PM projects. Some data suggest they may contribute positively to community efforts to reduce violence among youth, but insufficient information exists to know which projects best serve which students, and how projects should be implemented. Until consensus emerges, project personnel should carefully assess the implementation and impact of their activities. Routinely collected data, such as disciplinary actions, can be used for evaluation, often with only minor modification.

Restaurant wheelchair accessibility.

This study was designed to determine the compliance of restaurants to the wheelchair accessibility standards set forth in the Uniform Federal Accessibility Standards. The standards that were operationalized in this study are also found in Title III of the Americans With Disabilities Act of 1990. The data were collected at 120 sites in three midwestern states. For one who uses a wheelchair, parking the car is often an obstacle to eating out. Only 53% of the restaurants surveyed provide handicapped parking. Entering the building may also be a problem. Of the restaurants that required a ramp, only 66% provided them. Inside the restaurant, the key problems were accessible rest-rooms and the height of tables. The study provided comparisons between restaurants in rural and urban settings, as well as comparisons between conventional restaurants and fast food restaurants. No notable differences emerged for these comparisons.

Occupational therapists in private practice.

Although increasing numbers of occupational therapists are choosing to work in private practice, little data exist describing this sector of the profession. In the present study, experienced occupational therapists were asked about their moves into private practice, including (a) their motivation, (b) their preparation, and (c) their perceptions of the move's risks and benefits before and after the move. A survey was sent to a national random sample of 105 occupational therapists, 74 of whom responded. According to the survey, autonomy was the most important motivating factor for occupational therapists moving into private practice. However, once they were in private practice, the occupational therapists noted that increased income was a major benefit. These occupational therapists had planned for the risks of reimbursement, referral sources, and overhead but had not anticipated problems with staffing shortages. Incomes increased for occupational therapists who moved into private practice. The survey compared the incomes of occupational therapists before and after they entered private practice. It also compared their income and educational levels. Other comparisons included income and work experience, income and work role, and income and geographic location. Autonomy and financial considerations appear to be the overriding issues for occupational therapists choosing careers in private practice. Almost unanimously, the survey respondents said that private practice was a good career choice.

Human fetal response to vibroacoustic stimulation as a function of stimulus duration.

The effect of stimulus duration on the initial fetal heart rate (FHR) acceleration response was evaluated by assessing its amplitude and span following a single vibroacoustic stimulation with durations of 0 (sham), 1, 3, or 5 seconds. Statistically significant differences were observed in the mean amplitude and duration of acceleration in groups 3 and 5 when compared with groups 0 and 1 (P less than .05). In addition, groups 3 and 5 demonstrated significantly greater fetal reactivity than group 0 and a decrease in testing time over groups 0 and 1 (P less than .05). Our results suggest that the magnitude of the FHR acceleration response is dependent on the duration of the stimulus. Furthermore, a 3-second sound stimulus appears to be adequate for a shift to the fetal behavioral "awake" state.