In vitro antifungal and fungicidal activities and erythrocyte toxicities of cyclic lipodepsinonapeptides produced by Pseudomonas syringae pv. syringae

Recent increases in fungal infections, the few available antifungal drugs, and increasing fungal resistance to the available antifungal drugs have resulted in a broadening of the search for new antifungal agents. Strains of Pseudomonas syringae pv. syringae produce cyclic lipodepsinonapeptides with antifungal activity. The in vitro antifungal and fungicidal activities of three cyclic lipodepsinonapeptides (syringomycin E, syringotoxin B, and syringostatin A) against medically important isolates were evaluated by a standard broth microdilution susceptibility method. Erythrocyte toxicities were also evaluated. All three compounds showed broad antifungal activities and fungicidal actions against most of the fungi tested. Overall, the cyclic lipodepsinonapeptides were more effective against yeasts than against the filamentous fungi. Syringomycin E and syringostatin A had very similar antifungal activities (2.5 to > 40 micrograms/ml) and erythrocyte toxicities. Syringotoxin B was generally less active (0.8 to 200 micrograms/ml) than syringomycin E and syringostatin A against most fungi and was less toxic to erythrocytes. With opportunities for modification, these compounds are potential lead compounds for improved antifungal agents.     

Differential expression and autoradiographic localization of atrial natriuretic peptide receptor in spontaneously hypertensive and normotensive rat testes: diminution of testosterone in hypertension

Previous studies have shown that the diuretic hormone atrial natriuretic peptide (ANP) also regulates the steroidogenic responsiveness in isolated Leydig cells from mouse and rat testes. In the present study, we examined the distribution of specific receptors for ANP and C-type natriuretic peptide (CNP) in the testicular compartments of 12-week-old Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). We used an in vitro autoradiographic procedure on slide-mounted frozen testicular sections to localize the receptors of the natriuretic peptide hormone family using 125I-ANP and 125I-CNP as radioligands. A high level of specific 125I-ANP binding sites was localized largely in the Leydig cells of the interstitial compartment; other testicular cells were not significantly labeled. On the other hand, no significant difference was observed in 125I-CNP binding sites in the testicular cells of SHR and WKY. Semiquantitative analysis of the binding sites indicated that the density of 125I-ANP receptor binding in Leydig cells of WKY testis was ninefold higher than in those of SHR testis. A moderate level of 125I-ANP binding was also observed in seminiferous tubules, particularly in the spermatids of both SHR and WKY. 125I-ANP binding in WKY spermatids was approximately 2.5-fold higher than in SHR spermatids. Northern blot analysis showed that mRNA specific for guanylyl cyclase type A (Npra) was expressed at approximately twofold higher levels in WKY than in SHR testis. ANP (1 x 10(-8) mol/L) stimulated fourfold to fivefold increased levels of testosterone production in isolated Leydig cells from normotensive WKY compared with those from SHR. These findings support a new physiological role of ANP in Leydig cells, in which a functional relationship seems to exist between testicular ANP receptor expression and testosterone production and the state of hypertension in SHR.     

Effects of animal age on the responses along the outer segment of retinal rod photoreceptors

The aim of the present study was to determine whether the response gradient, known to exist along a rod outer segment, is influenced by age and developmental changes. Since intense light flashes saturate the responses of retinal rods and the time the response remains saturated increases from base to tip of the rod outer segment, one can use this difference in saturation times as a measure of the response gradient. During development and before sexual maturity (about one year postmetamorphosis) the differences between base and tip decreased, and this correlated with an acceleration of the light response in Xenopus laevis rods. The gradient along the rod outer segment then stabilized, while the response kinetics slowed and remained at a lower level. We conclude that photoreceptor responses and hence visual performance are affected by developmental changes.     

The seasonal variation of thermophilic campylobacters in beef cattle, dairy cattle and calves

The epidemiology of clinical cases of campylobacter in temperate climates shows a striking seasonality. In the search for a seasonal environmental reservoir changes in the carriage rate and population size of campylobacters in bovine hosts with time have been measured. Most probable number (MPN) methodology was used to enumerate thermophilic campylobacters in samples taken from the small intestines of beef cattle at slaughter and the fresh faeces of four dairy herds and new-born calves. Statistical analyses revealed significant evidence for seasonal periodicity in the data from dairy herds (P = 0.044). Not only was there a departure from constancy within a 12-month interval but these data revealed a true seasonality, that is, the same periodicity in numbers from one year to the next. Each herd had two peaks per year, in approximately spring and autumn. Peaks coincided in herds on neighbouring farms but those on farms in the north preceded those on farms in the south by 2 and 1 months, respectively (P = 0.0057). Intestinal carriage by beef cattle at slaughter was 89.4% (n = 360) with an average MPN campylobacters per gram fresh weight (MPN gfw-1) of 6.1 x 10(2). Average MPN gfw-1 in faeces from the dairy herds and calves were 69.9 (S.D. 3) and 3.3 x 10(4) (S.D. 1.7 x 10(2)). There was no evidence of seasonal periodicity in the size of the campylobacter population in beef cattle at slaughter. Calves were campylobacter free at birth but became colonized with a few days.     

Histomorphometry of the optic nerves of normal dogs and dogs with hereditary glaucoma

The beagle dog with hereditary primary open-angle glaucoma, unlike other animal models of human glaucoma, possesses a slowly progressive, sustained elevation of intraocular pressure. The effects of this insidious elevation in intraocular pressure on the axons of the optic nerves of three beagles at early stages of glaucoma and two beagles with advanced signs of glaucoma were compared to the optic nerves of four age-matched normal dogs. Plastic embedded optic nerve cross-sections (1 micron) 1 mm posterior to the lamina cribrosa were osmicated and stained with Toluidine Blue. Axons from 0.2 to > 2.0 microns in diameter were counted and measured in 16 cross-sectional regions of equal size within the whole optic nerve using a computerized image analysis system. The mean optic nerve axon diameters in the normal, early glaucomatous, and advanced glaucomatous dogs were 1.53, 1.25 and 1.13 microns respectively. The average total optic nerve axon count in the normal dogs was 148,303. Approximately 16% of the total axonal fibers were counted in each nerve. The counts of optic nerve axons 2.0 microns or greater in diameter were reduced by up to 60% in the central regions of the optic nerves of affected beagles. The large diameter axons of the peripheral optic nerve of the beagle dogs with glaucoma were more resistant to the elevated intraocular pressure. The counts of axons > 0.6 to 0.8 micron in diameter were significantly increased in glaucomatous beagles.     

Long-term survival of patients with Wegener''s granulomatosis from the American College of Rheumatology Wegener''s Granulomatosis Classification Criteria Cohort

Thirty children, aged between five and 15 years, were randomly allocated to receive postoperative analgesia from continuous morphine infusion (CMI) or patient controlled analgesia (PCA), also using morphine. The children's morphine consumption, respiratory rates, oxygen saturations and observation points during which they were sleeping were recorded during two periods, one on the day of operation and one the following day. The median dose of morphine consumed by the children using PCA was significantly larger than that consumed by the children having continuous infusions. Children aged between nine and 15 years using PCA had significantly lower minimum respiratory rates and minimum oxygen saturations than similarly aged children receiving continuous infusions. There was no significant difference between the PCA and CMI groups in the number of observation times that the children were asleep or in the minimum respiratory rates and minimum oxygen saturations in the awake and sleeping children.     

The regulation of cell volume: the mechanisms, coupled cellular reactions and pathophysiological significance

A review contemplates as a whole the problem of regulation of the cellular volume. The first part of the review considers the influences inducing alterations in the cells volume on account of changes in the tonicity of extracellular milieu and cytoplasm. The review elucidates the ways of implementing the fast and slow regulatory volume increase as well as decrease (RVI, RVD). The volume increase seems to enhance cells' proliferative ability due to activation of ions transport. The volume decrease needs further investigations. The last chapter of the review considers pathophysiological significance of the volume regulation in hyponatremia, diabetes, neutrophil activation.