Identification of neuronal nitric oxide synthase (nNOS) in human penis: a potential role of reduced neuronally-derived nitric oxide in erectile dysfunction

Erectile dysfunction (ED) commonly occurs in approximately 15% of men over 70 years old. A number of causes of this condition are recognised with the major mechanism of ED being an impaired relaxation of the corpus cavernosum (CC) smooth muscle and resulting reduction in penile blood flow. There are reports that ED is associated with a reduction in local levels of endothelium-derived nitric oxide (NO) with most studies focussing on the potential role of endothelial nitric oxide synthase (eNOS) in the erectile process. Since there is a recognised neurogenic component of ED we have studied altered nerve density and neuronal nitric oxide synthase (nNOS) distribution by immunohistochemistry and nNOS protein expression by western blot analysis in penises from patients with neurogenic ED and diabetes compared with control tissue obtained from patients undergoing gender reassignment. There was a significant reduction in nerve density in tissue from ED compared with control patients (P < 0.05). Immunostaining for nNOS colocalised with nerves and was reduced in ED tissue, as were nNOS protein levels. We have shown that nerve degeneration observed in penile tissue from ED patients is accompanied by a decrease in nNOS suggesting that reduced neuronal- as well as endothelium-derived NO plays a role in this condition.     

Use of robust statistical methods to determine the effect of fragile X on means and variance components of a quantitative trait

Owing to the presence of outliers, an estimated 3.5% in the ridge breadth data and 1.7% in the height data, the effect of fragile X on height and ridge breadth was examined using robust statistical techniques for data collected from 54 families afflicted with this disorder. It is shown that fragile X affects ridge breadth and height in a different manner. Fragile X women had a greater mean ridge breadth than normal women, whereas there was a similar trend, but no significant difference, between normal and fragile X men. Fragile X men were shorter than normal men, but no significant difference between the mean height of normal and fragile X women was observed. However, fragile X girls were shown to grow more quickly and to stop growing earlier than normal girls. An examination of the covariance between relatives classified according to fragile X status showed that for both traits the effect of fragile X was to reduce the covariance between parents and offspring, which produced the effect of departure from an additive polygenic model of inheritance. ©1995 Wiley-Liss, Inc.     

Changes in purinergic responses of the rabbit isolated central ear artery after chronic electrical stimulation in vivo.

1. The effect of chronic (4-16 days) electrical stimulation (5 Hz, 0.3 ms, 4-10 V) of the great auricular nerve in vivo on sympathetic cotransmission in the rabbit isolated central ear artery was examined. 2. Chronic stimulation had no significant effect on frequency-dependent (4-60 Hz) neurogenic contractions or contractile responses induced by exogenous noradrenaline (0.1-300 microM). 3. In contrast, contractions induced by exogenous alpha, beta-methylene ATP (10.0 microM) were significantly decreased in preparations from 16-day stimulated animals in comparison with sham-operated, 4-day and 8-day chronically stimulated animal groups. 4. It is concluded that chronic electrical stimulation of nerves supplying the ear artery may lead to the selective alteration of postjunctional P2x-purinoceptor mechanisms, while the effects mediated by post-junctional alpha 1-adrenoceptors remain unchanged.     

Hypothesis: a potential role for the vasa vasorum in the maintenance of vein graft patency

Autologous saphenous vein is the most commonly used conduit for coronary artery bypass surgery with more than 50% grafts occluding within 10 years. In conventional preparation the vein undergoes considerable surgical trauma with damage to the outer layers during harvesting. Within these regions are situated the vasa vasorum and small vessels providing oxygen and nutrients to the vessel wall. Certain vasa vasorum terminate in the vessel lumen where it is suggested that they have a physiological role. Preservation of the vasa vasorum of saphenous veins used as bypass conduits may play an important role in the maintenance of graft patency.     

Psychological status in female carriers of premutation FMR1 allele showing a complex relationship with the size of CGG expansion

We utilized a sample of 299 adult females aged between 19 and 86 years, carrying fragile X mental retardation (FMR1) alleles with small CCG expansions ranging from 50 to 141 repeats to analyse the relationships between psychological symptoms as assessed by the Symptom Checklist‐90‐Revised (SCL‐90‐R) and the size of the CGG repeat in the FMR1 gene. There were highly significant (negative) correlations between the size of the CGG repeat and a great majority of SCL‐90‐R subscale scores and all the global indices, suggesting that carriers of premutations in the mid‐size CGG repeat range may be at greatest risk for the development of psychiatric disorder.     

Ultrastructural localisation of serotonin and substance P in vascular endothelial cells of rat femoral and mesenteric arteries

Summary An electron microscopic-immunocytochemical study has been made on the localisation of serotonin and substance P in endothelial cells of femoral and mesenteric arteries of the rat. In the femoral and mesenteric arteries, less than 10% of the endothelial cells showed positive immunolabelling for these substances. The distribution of serotonin and substance P in endothelial cells was similar in both arteries. The immunoprecipitate was confined to the cytoplasm, including subcellular organelles. The results are discussed in terms of endothelial mechanisms of local control of blood flow.     

The hypothalamo-neurohypophysial system in streptozotocin-diabetic rats. Ultrastructural evidence for neuronal alterations in the supraoptic and paraventricular nuclei and in the neurohypophysis

The ultrastructure of the hypothalamo-neurohypophysial system of rats was examined 8 weeks after streptozotocin-induction of type I diabetes. These studies provided evidence for numerous neuronal alterations to the hypothalamo-neurohypophysial system in streptozotocin-diabetic rats. Changes were observed in the somata, dendrites and axons of both the supraoptic and paraventricular nuclei as well as in axon profiles in the neurohypophysis. Many of these changes suggest an increased activity of the hypothalamo-neurohypophysial complex, with increased synthesis of neurohypophysial hormones in the hypothalamus together with depletion of neurosecretory granules in axons in the neurohypophysis. Some degenerative changes, however, were also observed. It is proposed that chronic dehydration and hypoxia in diabetes may contribute to the ultrastructural reorganization of the hypothalamo-neurohypophysial complex in streptozotocin-diabetic rats.     

Comparison of graduates of regular curriculum and unified basic-science-clinical curriculum

The purpose of the study reported here was to identify differences between graduates who were in different curricula at Loyola University of Chicago Stritch School of Medicine. The physicians who had been in the special track, which combined the basic and clinical sciences throughout the program, chose specialties in family practice and psychiatry more than the regular track students and more often were salaried. One-third of those in the special curriculum felt the greatest strength of their medical school training was the preparation for independent learning, and a majority viewed a practice in which there were uncertainties in diagnosis as desirable. The traditional program graduate preferred to deal with cases in which important decisions had to be made rapidly and the effects of treatment could be immediately addressed. The two groups disagreed as to who should have major control of health care, on issues of peer review in the office, and on the emphasis physicians should give preventive care.     

Nonpalpable breast lesions: recommendations for biopsy based on suspicion of carcinoma at mammography

Carcinoma was found in 30% (119 of 400) of biopsy specimens obtained for mammographically suspicious but nonpalpable findings. The authors reviewed the mammograms of these 400 cases without knowledge of the biopsy results and placed each examination into one of four groups based on their suspicion for carcinoma: minimal (n = 82), slight (n = 91), moderate (n = 174), and high (n = 53). In 127 cases, mammograms showed either minimally suspicious calcifications (n = 33) or minimally (n = 49) or slightly (n = 45) suspicious masses. A 4.7% (six of 127) rate of carcinoma was found in these groups; five of the six cancers were in situ. Had follow-up mammography been done rather than biopsy for these 127 less suspicious lesions, it is probable that the delay in diagnosis would not have altered overall prognosis. In the remaining 273 patients, the positive predictive value of mammography for carcinoma would have risen from 30% (119 of 400) to 41% (113 of 273). The authors conclude that in the management of suspicious nonpalpable mammographic findings, the rate of carcinoma for lesions at biopsy can approximate 40%. This is almost double the rate of most published series.