Assessment of membrane potentials of mitochondrial populations in living cells.

Mitochondrial membrane potentials (MMP) reflect the functional status of mitochondria within cells. Fluorescent probes to estimate these potentials within cells have been available for some time, but measurements of populations of mitochondria are not possible by existing methods. Therefore, comparisons between different cell types (e.g., fibroblasts and neuroblastoma), fibroblast cell lines from different patients, or even the same cell following various experimental paradigms are not feasible. The current approach estimates populations of MMP within living cells at 37 degrees C using the combination of conventional fluorescence microscopy and three-dimensional deconvolution by exhaustive photon reassignment. With this method, raw images are acquired rapidly with low-intensity (nonlaser) light with minimal concentrations of fluorescent dye. The method uses the fluorescent dye tetramethylrhodamine methyl ester, which equilibrates in cells according to the Nernst equation and provides a numerical, replicable estimate of MMP for populations of cellular mitochondria. This method can detect either increases or decreases in MMP as small as 5%. Furthermore, MMP in different cell types appear distinct. Values in fibroblasts (-105 +/- 0.9 mV) and N2a cells (-81 +/- 0.7 mV) were very different by this method. This approach bridges investigations of individual mitochondria to those that assess MMP by examining global fluorescence from cells.

The Kubie "solution": an idea before its time?

Interpreted in historical context, Kubie's 1948 proposal to move the professional aspects of clinical psychology training and the awarding of the doctorate into the medical-school environment was an attempt to remedy a critical shortage of psychotherapists while maintaining medical control over the professional practice of psychology. The proposal failed, in part, because medicine had no legitimate claim to either training or regulating clinical psychologists. A parallel was drawn between that post-war situation and the current one in which many psychological practitioners are pressing for prescribing privileges in regard to psychoactive drugs, and similarities and important differences are noted between the two conditions. The requirement that medicine be involved importantly in the psychopharmacologic training of psychologists poses an acute problem concerning the maintenance of professional independence.

Pulmonary artery smooth muscle cell [Ca2+]i and contraction: responses to diphenyleneiodonium and hypoxia.

To investigate mechanisms of inhibition of hypoxic pulmonary vasoconstriction (HPV), we studied pulmonary artery smooth muscle cell (PASMC) responses to hypoxia, utilizing diphenyleneiodonium (DPI), which blocks HPV. We measured cell contraction in primary cultures of rat PASMC grown on collagen gels and cytosolic free Ca2+ concentration ([Ca2+]i) in PASMC grown on glass. DPI (5 and 20 microM) caused contraction of PASMC and increased [Ca2+]i. Omission of extracellular Ca2+ diminished the DPI-induced PASMC contraction and greatly reduced the increase in [Ca2+]i. DPI substantially inhibited KCl-induced PASMC contraction (1 microM DPI) and the increase in [Ca2+]i (5 microM DPI). Severe hypoxia contracted PASMC and quadrupled [Ca2+]i. DPI, 1 microM, substantially inhibited hypoxic contraction, but neither 1 nor 5 microM DPI diminished the hypoxia-induced increase in [Ca2+]i, which was greatly attenuated by 20 microM DPI. These data show 1) that DPI increases [Ca2+]i, accounting for DPI-induced PASMC contraction and 2) that 1 and 5 microM DPI inhibit the hypoxia-induced contraction but not the hypoxia-induced increase in [Ca2+]i, suggesting that DPI inhibits hypoxic PASMC contraction downstream of the Ca2+ signal by desensitizing the contractile apparatus and indicating a potential control point for modulation of HPV.

Aristotle, Galileo, and the DSM taxonomy: the case of schizophrenia.

With the diagnosis schizophrenia used as an example throughout, the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders's (American Psychiatric Association, 1994) approach to psychopathologic taxonomy is subjected to critical analysis as representing a fundamentally Aristotelian conception of the phenomena of mental disorders. This approach is contrasted, in the manner suggested by Kurt Lewin's early writing on the subject, with the Galileian mode of thought, emphasizing the dynamic causal matrix in which behavior occurs. Some of the positive implications of an altered view of the problem of taxonomy within the latter perspective are drawn out, and brief suggestions are made as to directions for the future.

Seamlessness in personality and its derangements.

A significant but often overlooked aspect of the circumplex structure of the domain of interpersonal functioning is its systematically continuous ordering of the quality of the behavioral variations addressed. It is a domain, in other words, explicitly lacking in categorical boundaries wherein a given behavior can be sharply discriminated from others proximal to it within a shared circumplex space; any identified border is at best a "fuzzy" one characterized by blending and interpenetration. It is argued that this observation has extended generalizability in respect to the organization of personality, rendering moot and suspect taxonomic systems that postulate categorical entities. The Diagnostic and Statistical Manual of Mental Disorders (4th ed.; American Psychiatric Association, 1994) used in the "diagnosis" of purported derangements of personality is one such system, one that would therefore be expected to yield certain predictable anomalies. These problems are illustrated with reference to the widespread occurrence of artifactual "comorbidities" among psychiatric diagnoses.

Dilemmas in the pathway of the DSM-IV.

It is argued that the format for developing recent versions of the Diagnostic and Statistical Manual of Mental Disorders (DSM) taxonomy is constrained in ways that seriously impair the quality of the product. These constraints include inappropriate assumption of a categorical model, ensured persistence of traditional categories of disorder, excessive concern with interdiagnostician agreement, insufficient attention to the issue of construct validity, and excessive preoccupation with clinician acceptance. These problems and certain others are illustrated with an analysis of the nosologic status of the schizophrenia construct. There is a significant danger that the adequacy of DSM-IV will be compromised by continuing difficulties of this sort.

Pancreas transplantation. A new program.

Sixteen pancreatico-duodenal transplants were performed on 15 insulin-dependent diabetics, aged 25-46, during a 20-month period beginning May 1, 1988. Fourteen patients received a combined cadaveric pancreas/renal transplant with bladder drainage. One patient received a second pancreas transplant 24 hours after the first pancreas graft failed due to portal vein thrombosis. One patient received a pancreas graft 3 years after kidney transplantation. Complications included five cases of hematuria, two bladder leaks, two wound infections, one cytomegalovirus pneumonia, three cases of graft pancreatitis, one pseudocyst, one urine reflux pancreatitis requiring conversion to pancreatico-enterostomy, and two late deaths. Average time to discharge was 17 days following transplant, with 2.9 re-hospitalizations per patient and an average of 38 in-hospital days during the first 6-12 months. Seventeen rejection episodes occurred in 12 patients, diagnosed by declining urine amylase and pH and/or finding of rejection on kidney biopsy. Patient and kidney graft survival is 87 per cent. Pancreas graft survival is 81 per cent (1-20 months follow-up). All patients are insulin-independent and normoglycemic. Mean glycosylated hemoglobin concentration is 4.0 +/- 0.9 post-transplant vs. 7.5 +/- 0.6 pretransplant. Mean serum creatinine is 1.4 +/- 0.7 mg/dl. A new program of pancreas transplantation can be successful in carefully selected diabetic patients, with special attention to avoidance of preservation injury to the pancreas during multiorgan donor procurement. Combined pancreatic/renal transplantation is believed to be the therapeutic treatment of choice in Type I diabetic patients who have impaired renal function and have no significant cardiovascular disease.

Pancreatitis necessitating urinary undiversion in a bladder-drained pancreas transplant.

After successful combined pancreaticoduodeno-renal transplant in an insulin-dependent diabetic, recurrent episodes of transplant pancreatitis were treated with Foley catheter drainage. The apparent cause of pancreatitis was increased pressure on the pancreatic duct due to infrequent voiding and a large bladder. A frequent voiding program partially relieved the pancreatitis, but final resolution necessitated conversion of the pancreaticoduodeno-cystostomy to a Roux-en-Y duodenojejunostomy at 6 months posttransplant. Both renal and pancreatic function are stable after 1 year, with no recurrence of pancreatitis since urinary undiversion. We believe pressure pancreatitis or urine reflux pancreatitis to be an infrequently reported cause of graft dysfunction in bladder-drained pancreas transplant recipients.

Assessment: what role the assessor?

The advent of automated assessment contains the seeds of both threat and promise for professional assessors. Placing the problem in the historical and sociological contexts, this article examines computer-based test interpretation (CBTI) and the frequently misunderstood role of actuarial data in relation to it. I argue that sound clinicianship is central not only to the development of adequate CBTI systems, but also to the systems' appropriate and skillful use in practice. When properly utilized by otherwise well-qualified clinicians, CBTI can substantially enhance practice.

Seizure-induced delay of puberty in female rats: effects of age, stress and opioid antagonists.

We have shown that pre- and post-pubertal female rats are sensitive to seizures. For example, daily convulsions commencing at 24 days of age delay puberty. Here we examine the effect of seizures at various ages. In addition, because opioid peptides are implicated in regulating the onset of puberty and are activated by convulsions, we also investigate the effect of opioid antagonists in the seizure-induced delay of puberty. A single daily electroconvulsive shock (ECS) was given for 10 days to neonatal (days 2-11), infantile (days 15-24) and juvenile (days 22-31) rats. The treatment delayed vaginal opening (VO) in juvenile rats. Neonatal and infantile rats were unaffected. VO was also delayed by daily ECS for only 5 days in the late juvenile (days 27-31) period. The opioid receptor antagonists naloxone, naltrexone and nalmefene injected before and after single daily ECS were unable to block this effect of ECS on VO. To examine whether the effect of ECS is related to stress, we examined several stressors known to induce opioid-mediated alterations in gonadotrophin secretion. Footshock, immobilization and ether stress administered in the juvenile period (days 27-31) did not affect the timing of VO. In addition, rats anaesthetized with halothane, and then given ECS, still showed a delay of VO. These data demonstrate that rats in the late juvenile stage of development are most sensitive to convulsions. We also suggest that opioids are not critical to the mechanism by which the ECS disturbs puberty, and that ECS elicits its effect seemingly independently of the convulsive stress.