Domoic acid enhances the K(+)-evoked release of endogenous glutamate from guinea pig hippocampal mossy fiber synaptosomes.

The presynaptic effects of domoic acid (Dom) on hippocampal mossy fiber synaptic transmission were examined using a subcellular fraction enriched in mossy fiber synaptosomes. Domoic acid significantly increased the K(+)-evoked release of endogenous glutamate from superfused guinea pig mossy fiber synaptosomes. The presynaptic facilitation produced by Dom was dose-dependent and was antagonized by the prior application of 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). At a concentration of 30 microM, both domoic acid and kainic acid significantly increased the extent to which membrane depolarization augmented the availability of cytosolic free calcium in mossy fiber synaptosomes. These results are consistent with the suggestion that domoic acid enhances the release of mossy fiber neurotransmitters in the guinea pig hippocampus through the activation of a CNQX-sensitive presynaptic receptor.

Inhibition of glutamate release: a potential mechanism of action for the anticonvulsant U-54494A in the guinea pig hippocampus.

U-54494A, a 1,2-diamine, is a potent inhibitor of glutamate release in a synaptosomal preparation that is highly enriched with hippocampal mossy fiber (MF) nerve endings. At a concentration of 100 microM, U-54494A significantly reduced the availability of cytosolic free calcium (Ca2+) in depolarized MF-enriched synaptosomes by 30% and inhibited the K(+)-evoked release of endogenous glutamate by 85%. The extent to which glutamate release was inhibited allows us to conclude that U-54494A acts directly on the MF subpopulation of glutamatergic nerve endings in the guinea pig hippocampus. In addition, this anticonvulsant effectively countered the presynaptic facilitation of K(+)-evoked glutamate release that is induced by kainic acid (KA). Thus, while KA (1 mM) by itself nearly doubled the rate of K(+)-evoked glutamate release, there was no net increase in the presence of both KA and U-54494A (100 microM). However, the opposed effects of these two compounds on glutamate release do not appear to be due to a direct interaction. In the presence of U-54494A (100 microM), KA (1 mM) significantly enhanced the K(+)-evoked release of glutamate. Finally, it is demonstrated that the KA-induced enhancement of glutamate release does not require the depolarization-induced entry of extracellular Ca2+.

A comparative study of the effects of UVC irradiation on select procaryotic and eucaryotic wound pathogens.

Managing wounds infected with a mixture of several types of microorganisms such as bacteria (procaryotes) and fungi (eucaryotes) is a challenging clinical situation. The purpose of this study was to determine the effectiveness of ultraviolet light (UVC) in eradicating select procaryotic and eucaryotic organisms, in both pure culture and mixed cultures in vitro. Five replications of each organism or mixture of organisms (10(6) organisms/mL singly or 10(15) organisms/mL mixed culture) were plated. The cultures were treated with a UVC light 1 inch from the surface. Irradiation times were 0, 2, 3, 4, 5, 15, 30, 45, 60, 90, 120, and 180 seconds. Bacterial cultures were incubated and colony counts performed. Upon exposure to UVC, a 99.9% kill rate was obtained at 3 to 5 seconds for the procaryotic organisms (Pseudomonas aeruginosa and Mycobacterium abscessus) tested. However, 15 to 30 seconds of UVC treatment was required to obtain 99.9% kill of the eucaryotic organisms (Candida albicans, Aspergillus fumigatus) tested. This study demonstrates a decreasing sensitivity of evolutionarily more complex organisms to UVC. This study also provides further evidence that short exposure times to UVC are detrimental to procaryotic and simple unicellular eucaryotic organisms while sparing more complex multicellular organisms.

The effects of UVC irradiation on group A streptococcus in vitro.

Streptococcus pyogenes (group A streptococcus--GAS) is a common cause of necrotizing fasciitis (NF)--a severe infection of the subcutaneous soft tissue. The purpose of this study was to determine if the topical therapy ultraviolet light C (UVC) is effective in killing GAS in vitro and to evaluate the most effective treatment parameters for use with UVC therapy. Five replications of GAS at 10(8) organisms/mL were plated. The cultures were treated with a UVC light 1 inch from the surface. Irradiation times were as follows: 0, 2, 3, 4, 5, 15, 30, 45, 60, 90, 120, and 180 seconds. Bacterial cultures were incubated and colony counts performed. A second set of GAS cultures were exposed to UVC for 30, 90, and 120 seconds either once daily (qd) or twice daily (bid). Kill rates were 99.9% for GAS at 4 seconds to 180 seconds. Kill rates of 99.9% were also obtained at 30 seconds and 90 seconds when UVC treatment was given either qd or bid. This data indicates that UVC is bactericidal for GAS at times as short as 4 seconds. In addition, UVC treatment was not effective when administered through thin film dressings.

The effects of ultraviolet radiation on antibiotic-resistant bacteria in vitro.

Wound infections produced by antibiotic-resistant bacterial strains are particularly difficult to manage. This study examined the effectiveness of ultraviolet (UV) light treatment in killing antibiotic-resistant strains of Staphylococcus aureus and Enterococcus faecalis in vitro. Between 2 and 5 replications of each organism at 10(8) organisms/ml were prepared and plated on sheep blood agar medium and treated with UV light (254 nm, 15.54 mW/cm2 output). Irradiation times were 0, 2, 5, 8, 15, 30, 45, 60, 90 or 120 seconds. Bacterial cultures were then incubated at 35 degrees C for 24 hours. Kill rates were 99.9 percent for the methicillin-resistant strain of S. aureus (MRSA) at 5, 8, 15, 30, 45, 60 seconds and 100 percent at 90 and 120 seconds. Kill rates were 99.9 percent at 5, 8, 15, 30 seconds for vancomycin-resistant E. faecalis (VRE) and 100 percent at 45, 60, 90, 120 seconds. Similar results were found with UV light treatment of the antibiotic-susceptible strains of S. aureus and E. faecalis. A significant difference in kill rates at 30 seconds of UV exposure was detected between the antibiotic-resistant strain of S. aureus and the antibiotic-resistant strain of E. faecalis (Student's t test, p < 0.01). Significant differences were also detected in the kill rates at 30 second exposure times for the antibiotic-susceptible strains of S. aureus and E. faecalis. These findings suggest that the Enterococcal bacteria is more susceptible to the killing effects of UV. This data also suggests that UV light at 254 nm is bactericidal for antibiotic-resistant strains of S. aureus and E. faecalis at times as short as 5 seconds and that the enterococcal bacteria is more susceptible to the killing effects of UV. With recommended patient treatment times for infected wounds being significantly longer than 5 seconds, this data indicates that patient treatment times need to be re-examined.

Analysis of practice-role perceptions of physical therapy, occupational therapy, and speech-language therapy students.

The purpose of this study was to determine whether physical therapy (PT), occupational therapy (OT), and speech-language therapy (SLP) students shared common perceptions of the practice roles of the three disciplines. The survey instrument used in this study contained 55 questions that addressed practice-role perceptions. The questions were based on a case study. A total of 172 undergraduate students (PT 71, OT 52, SLP 49) from a southeastern university participated. Chi-square test of association was used to analyze the data. Results showed that PT, OT, and SLP students shared common perceptions of administrative and educational practice roles but differed on their perceptions of assessment and physical/mental treatment roles. Practice-role confusion was particularly acute between OT and PT and between OT and SLP students in these areas.

Dextran sodium sulfate inhibition of real-time polymerase chain reaction amplification: a poly-A purification solution.

BACKGROUND: Dextran sulfate sodium (DSS) induces experimental colitis and promotes colitis-associated cancer in rodents. Here we document potent inhibition of real-time quantitative polymerase chain reaction (qPCR) using cDNA from DSS-exposed mouse tissues, which complicates gene expression analysis. METHODS: We characterize DSS inhibition of qPCR in-vitro and in a wide array of murine tissues following ingestion of DSS. We examine different approaches to RNA purification prior to cDNA synthesis in order to optimize real-time polymerase chain reaction amplification and gene expression analysis. RESULTS: DSS inhibits qPCR amplification of cDNA between 1 and 10 nM. Orally administered DSS interferes with qPCR amplification of cDNA derived from multiple tissues. Poly-A purification of DSS-exposed RNA allows reliable and cost-effective gene expression analysis in DSS-exposed tissue. CONCLUSIONS: DSS is a potent inhibitor of real-time qPCR amplification and interferes with tissue-specific gene expression analysis in DSS-exposed mice. Poly-A purification of tissue-derived RNA results in reliable and cost-effective gene expression analysis in DSS-exposed mice.

A clinical comparison of nomifensine and amitriptyline.

1. The study consists of a double-blind evaluation of nomifensine and amitriptyline in a group of 37 patients with primary depressive illness. 2. The patients were referred by their family doctors on the basis that they would ordinarily have been prescribed a tricyclic antidepressant drug. Random allocation to the treatment groups took place. Assessment took place at weekly intervals over a 4-week period using the Visual Analogue Scale for depression and anxiety, and a side-effects check-list. Patients were also assessed on the Hamilton Depression Scale before the onset and at the end of the trial. 3. No significant difference was found between the two groups as regards relief from depression and anxiety, although marginal differences were found in favour of the amitriptyline group. 4. The overall frequency of side-effects was similar in the nomifensine and amitriptyline patients, But the development of severe side-effects was significantly more common in the amitriptyline group.

Trazodone. A comparative clinical and predictive study.

The clinical efficacy and tolerability of trazodone and amitriptyline were compared in 74 hospital patients suffering from depressive illness. The daily doses of trazodone and amitriptyline were 150-300 mg and 75-225 mg, respectively, with half-strength capsules for patients over the age of 65 years. Twenty-five and 29 patients receiving trazodone and amitriptyline, respectively, completed the 6 week treatment period. Antidepressant activity was measured using the Hamilton Depression Rating Scale (HDRS), the Zung Scale of Depression, visual analogue scales and a Global Assessment Scale. Trazodone and amitriptyline were both effective but not statistically different from each other in terms of antidepressant action. Moreover, patients with neurotic or endogenous depression responded equally well on either treatment. Trazodone was less troublesome in respect of the persistent dry mouth and severe adverse psychiatric reactions which occurred with amitriptyline. Patients should be advised to take trazodone after meals.

Facial dyskinesia: a 16-year follow-up study.

The 109 female survivors of a mental hospital population surveyed in 1965 for facial dyskinesia were followed up 16 years later. The 99 survivors with non-organic brain syndromes were analysed. Prevalence of dyskinesia had risen from 18.4% to 46.5% during follow-up and its development was significantly associated with neuroleptic dosage. Enlarged ventricles on brain scans were significantly associated with dyskinesia, cognitive impairment and neuroleptic prescribing.

The comparative antidepressant value of lofepramine and amitriptyline. Results of a controlled trial with comments on the scales used.

A double-blind controlled trial comparing the antidepressant activity of amitriptyline with lofepramine is reported. Forty-six patients entered the 4-week trial. Analysis of the Hamilton Depression Rating Scale scores at the beginning and end of the trial showed no significant difference between the therapeutic efficacy of lofepramine and amitriptyline. However, patients with endogenous depression responded significantly more rapidly to lofepramine as measured by Visual Analogue Scales and showed a significantly greater degree of clinical improvement after 4 weeks' treatment, as measured by Global Assessment. Adverse effects were similar in the two treatment groups. The use of rating scales in trials of depressive illnesses is discussed. The Visual Analogue Scale for depression was found to be a simple, useful and valid measure.

cDNA cloning of mouse and human cholesterol 25-hydroxylases, polytopic membrane proteins that synthesize a potent oxysterol regulator of lipid metabolism.

Oxysterols regulate the expression of genes involved in cholesterol and lipid metabolism and serve as intermediates in cholesterol catabolism. Among the most potent of regulatory oxysterols is 25-hydroxycholesterol, whose biosynthetic enzyme has not yet been isolated. Here, we report the cloning of cholesterol 25-hydroxylase cDNAs from the mouse and human. The encoded enzymes are polytopic membrane proteins of 298 and 272 amino acids, respectively, which contain clusters of histidine residues that are essential for catalytic activity. Unlike most other sterol hydroxylases, cholesterol 25-hydroxylase is not a cytochrome P450, but rather it is a member of a small family of enzymes that utilize diiron cofactors to catalyze the hydroxylation of hydrophobic substrates. The cholesterol 25-hydroxylase gene lacks introns, and in the human it is located on chromosome 10q23. The murine gene is expressed at low levels in multiple tissues. Expression of cholesterol 25-hydroxylase in transfected cells reduces the biosynthesis of cholesterol from acetate and suppresses the cleavage of sterol regulatory element binding protein-1 and -2. The data suggest that cholesterol 25-hydroxylase has the capacity to play an important role in regulating lipid metabolism by synthesizing a co-repressor that blocks sterol regulatory element binding protein processing and ultimately leads to inhibition of gene transcription.

Mortality and facial dyskinesia.

In 1965 a psychiatric in-patient population was surveyed for the prevalence of facial dyskinesia. The present investigation reports on their survival time. Among male and female patients with functional disorders (mostly schizophrenia) there was a strong association between moderate or severe facial dyskinesia and shortened survival, but no clinical factors were found to explain this. Mild facial dyskinesia in functional disorders was not associated with reduced life expectancy and may be attributable to the general effects of ageing rather than to a specific pathological process. Among patients with primary organic brain syndromes, dyskinesia was not associated with reduced life expectancy.

Molecular basis for feedback regulation of bile acid synthesis by nuclear receptors.

The catabolism of cholesterol into bile acids is regulated by oxysterols and bile acids, which induce or repress transcription of the pathway's rate-limiting enzyme cholesterol 7alpha-hydroxylase (CYP7A1). The nuclear receptor LXRalpha binds oxysterols and mediates feed-forward induction. Here, we show that repression is coordinately regulated by a triumvirate of nuclear receptors, including the bile acid receptor, FXR; the promoter-specific activator, LRH-1; and the promoter-specific repressor, SHP. Feedback repression of CYP7A1 is accomplished by the binding of bile acids to FXR, which leads to transcription of SHP. Elevated SHP protein then inactivates LRH-1 by forming a heterodimeric complex that leads to promoter-specific repression of both CYP7A1 and SHP. These results reveal an elaborate autoregulatory cascade mediated by nuclear receptors for the maintenance of hepatic cholesterol catabolism.

Evidence for the corelease of dynorphin and glutamate from rat hippocampal mossy fiber terminals.

Hippocampal mossy fiber (MF) nerve endings may be isolated in a subcellular fraction (P3) that releases both prodynorphin-derived peptides and glutamate (Glu) in a calcium-dependent manner when depolarized. However, this isolation procedure does not yield a pure preparation of MF synaptosomes. The present study evaluates the proportion of dynorphin (Dyn) and Glu that is released from synaptosomes in the P3 fraction that are of MF origin. We have addressed this issue by determining the degree to which a selective lesion of the dentate granule cell/MF system in vivo concomitantly reduces the exocytosis of Dyn and Glu from the P3 subcellular fraction. Unilateral injections of colchicine into the dentate gyrus resulted in a substantial and selective degeneration of the granule cell/MF pathway in the rat hippocampal formation. The overall integrated density of the Timm-stained band, which corresponds to the position of the MF terminal field, was estimated to be reduced by 75%. After this extensive loss of MF boutons, the K(+)-evoked release of Dyn and Glu from the P3 fraction was reduced by 95 and 51%, respectively. The loss of Timm staining and evoked Dyn release indicate that colchicine effectively eliminated MF synaptosomes from the P3 fraction. Those subcellular entities that were not destroyed by colchicine comprised approximately 50% of the protein and evoked Glu release measured by using the P3 fraction. In addition, the present results demonstrate that the inhibitory potency of the kappa opioid agonist U-50,488H was not altered by the elimination of MF boutons from this synaptosomal preparation. This finding indicates that U-50, 488H is capable of suppressing Glu exocytosis from both MF and non-MF synaptosomes. These results are consistent with the hypothesis that Dyn peptides and Glu are co-released from hippocampal MF terminals.