Phosphorylation-dependent regulation of axon fasciculation.

Axons often grow along other axons to produce bundles called fascicles, and a number of cell adhesion molecules (CAMs) found on axon surfaces contribute to this process. The surprising observation that Fab fragments against individual CAMs can completely block fascicle formation suggests that the different axon-associated CAMs are functionally linked. The present studies investigate whether such a linkage might reflect intracellular regulatory mechanisms. Results obtained with chicken retinal explants in culture indicate that fasciculation is highly sensitive to cytoplasmic protein phosphorylation by means of a mechanism that does not alter levels of CAM expression. Moreover, the potent effect of individual Fabs on fasciculation disappears with enhanced phosphorylation. These observations suggest that growing axons possess a general regulatory process for the multiple CAMs that participate in fasciculation.     

F-19 MR imaging of glucose metabolism in the rabbit

Noninvasive metabolic magnetic resonance (MR) imaging reflecting glucose metabolism in the aldose-reductase-sorbitol (ARS) pathway was performed in the rabbit head; after administration of the fluorinated glucose analogue 3-fluoro-3-deoxy-D-glucose (3FD-glucose), fluorine-19 images were generated. Images of 3FD-glucose showed significant 3FD-glucose uptake by adipose tissue, indicating its buffering effects in case of excess loads of glucose. Images of 3-fluoro-3-deoxy-D-sorbitol (3FD-sorbitol) demonstrated the spatial distribution of aldose reductase activities and significant sorbitol accumulation in the lens. Images of 3-fluoro-3-deoxy-D-fructose (3FD-fructose) showed preferential uptake of fructose by muscle tissue. The extremely low toxicity of 3FD-glucose indicates promise for its clinical application in metabolic imaging.     

Computer simulations and the use of radiolabelled sulphur colloid to measure the efficiency of the mononuclear phagocyte system

Technique are described whereby the clearance of the radiolabelled blood borne colloid can be continuously and reproducibly measured non-invasively from the same animal in vivo or from the isolated perfused intact liver in vitro. Using these techniques, the rate of removal of radiolabelled sulphur colloid by the mononuclear phagocytes in vivo and in vitro was shown to be biexponential. The pattern of clearance of colloid and the factors contributing to this were analysed with the aid of a computer program which mimicked the in vitro liver perfusion.     

Creatine kinase isoenzyme (CK-BB) in combination to prostatic acid phosphatase measured by RIA in the diagnosis of prostatic cancer

Summary Creatine kinase isoenzyme (CK-BB) measured by mass was used to determine its value in the early diagnosis of prostatic cancer. Sera of patients with prostatic carcinoma of various stages (treated and untreated) were compared to normal male sera and sera of patients with benign hyperplasia of the prostate (BPH) with respect to CK-BB. The sera were simultaneously tested for PAP content. The sensitivity of the CK-BB-RIA was 1.63+/-0.08 g/l and reproducibility in the higher and lower concentration range 7.6% and 10.5%, respectively. CK-BB alone or in combination with PAP is no marker for early detection of prostatic cancer. In individual cases changes occurred similar to those found with a malignant growth of the prostate.     

Effect of sexual activity on cycle ergometer stress test parameters, on plasmatic testosterone levels and on concentration capacity. A study in high-level male athletes performed in the laboratory

BACKGROUND: The purpose of this study was to investigate the effect of sexual activity on cycle ergometer stress test parameters, on plasmatic testosterone levels and on concentration capacity in high-level male athletes. METHODS: Experimental design. Analysis of two days of testing accomplished in a laboratory setting, comparing a day with to a day without sexual activity (control day). Participants. Fifteen high-level male athletes, consisting of 8 team players, 5 endurance athletes and 2 weight-lifters, participated in the study. Measures. Each subject completed the following on each test day: two maximal graded stress tests on a cycle ergometer and a one-hour exercise stress test coupled to an arithmetic mental concentration test. Blood samples of testosterone were obtained and cardiac activity of each athlete was monitored with a 24-hour ECG tape recording over the two test days. RESULTS: Significantly higher differences were achieved for post-effort heart rate (HR) values at 5 minutes (p<0.01) and at 10 minutes (p<0.01) during the recovery phase of the morning stress test 2 hours after sexual activity. These differences disappeared during the recovery phase of the afternoon stress test performed approximately 10 hours after sexual intercourse took place. CONCLUSIONS: Our findings show that sexual activity had no detrimental influence on the maximal workload achieved and on the athletes' mental concentration. However, the higher posteffort HR values after the maximal stress test on the morning of sexual intercourse suggest that the recovery capacity of an athlete could be affected if he had sexual intercourse approximately 2 hours before a competition event.     

Enzymatic removal of polysialic acid from neural cell adhesion molecule perturbs the migration route of luteinizing hormone-releasing hormone neurons in the developing chick forebrain

During development in the chick embryo, luteinizing hormone-releasing hormone (LHRH) neurons migrate along the olfactory nerve from the olfactory epithelium to the forebrain. At embryonic day 5.5 (E5.5) to E6.0, the majority of LHRH neurons begin to enter the medial forebrain and then course dorsocaudally along the forebrain substance just beneath the pia matter in association with the somatostatin (SST)-positive fibers, which branch medially from the SST-positive olfactory nerve. By E6.5, the neurons and SST-positive medial branch of the olfactory nerve have proceeded toward the septal area. Intense immunoreactivity for the polysialylated form of neural cell adhesion molecule (PSA-NCAM) on both the LHRH neurons and the SST-positive fibers during this period suggests that this less adhesive form of NCAM is involved in the migratory process. This possibility was examined by using a polysialic acid (PSA)-specific endoneuraminidase. PSA removal did not alter the behavior or appearance of the SST-positive olfactory fibers within the migration pathway. However, it induced a significant deviation of migrating LHRH neurons from the regular path in the forebrain. The effect of PSA removal is more likely to involve changes in the interaction of the migrating neurons with a subset of the SST-positive olfactory fibers and/or other elements in the forebrain rather than an alteration in the pattern of their axonal substrate. On the basis of these results, it is suggested that PSA contributes to the specific pattern of LHRH neuronal migration in the forebrain by limiting interaction of these LHRH neurons with their surrounding environment.     

Limited engraftment of donor microbiome via one-time fecal microbial transplantation in treated HIV-infected individuals

Many HIV-infected individuals on antiretroviral therapy (ART) exhibit persistent systemic inflammation, which predicts morbidity and mortality. ART-treated subjects concurrently exhibit marked compositional alterations in the gut bacterial microbiota and the degree of dysbiosis correlates with systemic inflammation. Whether interventions to modulate the microbiome can affect systemic inflammation is unknown. An open-label fecal microbial transplantation (FMT) was delivered by colonoscopy to asymptomatic HIV-infected ART-suppressed individuals without antibiotic pre-treatment. Stool was assessed before and after FMT for engraftment of donor microbes, and peripheral blood was assayed for immune activation biomarkers. Six participants received FMT and 2 participants served as controls. No serious adverse effects occurred during 24 weeks of follow-up. At baseline, HIV-infected individuals exhibited microbiota profiles distinct from uninfected donors. During the 8 weeks post-FMT, recipients demonstrated partial engraftment of the donor microbiome (P < 0.05). Recipient microbiota remained significantly distant from donors, unlike that observed following FMT for treatment of C. difficile infection. Systemic inflammatory markers showed no significant change post-FMT. FMT was well-tolerated in ART-treated, HIV-infected individuals. Engraftment was detectable but modest, and appeared to be limited to specific bacterial taxa. Whether antibiotic conditioning can enhance engraftment and the capacity of microbiota to modulate inflammation remains to be investigated.     

Streptococcal Toxic Shock Syndrome in Two Patients Infected by a Colonized Surgeon

Summary The incidence of severe invasive infections caused by Streptococcus pyogenes, a group A streptococcus (GAS), has increased in the past 10 years. Most cases occur outside of the hospital setting. We report on two patients with nosocomial streptococcal toxic shock syndrome (StrepTSS). In patient 1 the syndrome was associated with the development of necrotizing fasciitis following inguinal hernia repair. Patient 2 suffered from StrepTSS shortly after receiving a tetanus vaccine in her left deltoid. Epidemiologic investigations of these cases, which were noted within 48 hours of each other, showed that the same surgeon performed the vaccination on patient 2 after assisting a colleague during the hernia repair procedure on patient 1. He was found to be a nasal carrier of GAS. All GAS isolates from the patients and the surgeon were indistinguishable by pulsed field gel electrophoresis. PCR analysis demonstrated the presence of streptococcal pyogenic exotoxins A and F. All strains were of the T-1 serotype and possessed the gene for M-protein 1. This report demonstrates that a virulent strain of GAS may be spread by asymptomatically colonized medical personnel via the air route. Received: February 26, 1999 · Revision accepted: May 26, 1999     

Recurrence of stenosis after first and repeat coronary angioplasty. Clinical and angiographic follow-up

The incidence of restenosis after initially successful first coronary angioplasty and the long-term effectiveness of repeat angioplasty for recurrence were examined on the basis of data on 282 consecutive patients with successful angioplasty. Primary success of first coronary angioplasty was obtained in 86% of patients and major complications (death, acute myocardial infarction and emergency coronary bypass surgery) occurred in 5% of patients. Control coronary angiography 10 +/- 6 months after successful angioplasty in 195 patients documented recurrence of stenosis in 33%. Repeat angioplasty was attempted in 52 patients with a primary success of 92%. One patient sustained an acute infarction as a complication of the procedure (2%). Control coronary angiography 7 +/- 4 months after a successful second procedure in 28 patients documented a second recurrence of stenosis in 39%. Recurrence rates after first and second coronary angioplasty were comparable (33 vs 39%, ns) but, for lesions of the left anterior descending coronary artery, recurrence was observed more frequently after second than after first angioplasty (47 vs 31%, p less than 0.05). Restenosis after second angioplasty, but not after first, was more frequent in women than in men. Patients with second recurrence were older than those with continuing angiographic success (59 +/- 8 vs 50 +/- 12 years, p less than 0.05). Recurrence was treated by a third coronary angioplasty in 5 patients, with success in all. Clinical follow-up 8 +/- 6 months after the last successful procedure was available for all 43 patients with repeat angioplasty who did not cross over to coronary surgery.(ABSTRACT TRUNCATED AT 250 WORDS)