Suppurative corneal ulceration in Bangladesh

Suppurative keratitis is an important preventable cause of blindness, particularly in the developing world. This study analyses 142 cases of suppurative keratitis referred to Chittagong Eye Infirmary, Bangladesh. Some 53.5% of cases were bacterial and 35.9% were fungal. The five most common pathogens were: Pseudomonas sp. 24%, Streptococcus pneumoniae 17%, Aspergillus sp. 13%, Fusarium sp. 7% and Curvularia sp. 6%. Gram stain and culture results were consistent in 62.6% of cases. Previous antibiotic treatment was a significant factor for failure of culture isolation and less so for Gram stain failure. On Gram stain, 55.9% of pseudomonal cases were missed, but only 2% of fungal cases were missed. Over all, Gram stain had a sensitivity of 62% and positive predictive value of 84% for bacterial cases, and 98% and 94% for fungal cases, respectively. Fungal ulcers were typically filamentous, but an antecedent history of trauma was not common. The most frequent injury was due to rice grains, but the inoculum appeared to be introduced during eye washing with contaminated water. Pseudomonal ulcers occurred most frequently in the monsoon season, and Fusarium cases were seen only in the hot, dry season.     

Nonheme iron in sickle erythrocyte membranes: association with phospholipids and potential role in lipid peroxidation

Previous studies documented the abnormal association of heme and heme proteins with the sickle RBC membrane. We have now examined RBC ghosts and inside-out membranes (IOM) for the presence of nonheme iron as detected by its formation of a colored complex with ferrozine. Sickle ghosts have 33.8 +/- 18.2 nmol nonheme iron/mg membrane protein, and sickle IOM have 4.3 +/- 3.0 nmol/mg. In contrast, normal RBC ghosts and IOM have no detectable nonheme iron. The combination of heme and nonheme iron in sickle IOM averages nine times the amount of membrane- associated iron in normal IOM. Kinetics of the ferrozine reaction show that some of this nonheme iron on IOM reacts slowly and is probably in the form of ferritin, but most (72% +/- 18%) reacts rapidly and is in the form of some other biologic chelate. The latter iron compartment is removed by deferoxamine and by treatment of IOM with phospholipase D, which suggests that it represents an abnormal association of iron with polar head groups of aminophospholipids. The biologic feasibility of such a chelate was demonstrated by using an admixture of iron with model liposomes. Even in the presence of tenfold excess adenosine diphosphate, iron partitions readily into phosphatidylserine liposomes; there is no detectable association with phosphatidylcholine liposomes. To examine the bioavailability of membrane iron, we admixed membranes and t-butylhydroperoxide and found that sickle membranes show a tenfold greater peroxidation response than do normal membranes. This is not due simply to a deficiency of vitamin E, and this is profoundly inhibited by deferoxamine. Thus, while thiol oxidation in sickle membranes previously was shown to correlate with heme iron, the present data suggest that lipid peroxidation is related to nonheme iron. In control studies, we did not find this pathologic association of nonferritin, nonheme iron with IOM prepared from sickle trait, high-reticulocyte, postsplenectomy, or iron-overloaded individuals. These data provide additional support for the concept that iron decompartmentalization is a characteristic of sickle RBCs.     

Serum ionic fluoride levels in haemodialysis and continuous ambulatory peritoneal dialysis patients

High serum fluoride (F-) in patients with chronic renal failure (CRF) and end-stage renal disease (ESRD) is associated with risk of renal osteodystrophy and other bone changes. This study was done to determine F- in normal healthy controls and patients with ESRD on haemodialysis (HD) or peritoneal dialysis (PD). Seventeen healthy controls (12 males, 5 females) and 39 ESRD patients on dialysis (17 males, 22 females) were recruited in the study in a community with 47.4 +/- 3.28 microM/l (range 44-51 microM/l) of F- content in drinking water. Control subjects showed a mean serum F- concentration of 1.08 +/- 0.350 microM/l. Males in control group showed slightly higher F- levels (1.15 +/- 0.334, range 0.55-1.9 microM/l) than females (0.92 +/- 0.370, range 0.6-1.5 microM/l). Mean serum F- concentration did not correlate significantly with age and sex among control subjects, whereas such correlation was observed in patients with ESRD on dialysis. Mean serum F- concentration was significantly higher in patients on dialysis (2.67 +/- 1.09, range 0.8-5.2 microM/l) than normal controls. When grouped according to sex, the mean serum F- concentration in males (3.05 +/- 1.04, range 1.8-5.2 microM/l) was significantly higher than females (2.38 +/- 1.08, range 0.8-5.2 microM/l). When patients were grouped according to age, it was observed that F- concentration was significantly higher in patients with age groups 21-70 (2.86 +/- 1.05) than those with age group 13-20 years (1.42 +/- 0.531). Thus F- concentration correlated with age and sex, being higher in males and above 20 years. Despite appreciable clearance of F- (39-90%) across the peritoneum, patients on CAPD showed higher serum F- concentration than those on HD (3.1 +/- 1.97 vs 2.5 +/- 1.137 microM/l). Of the total 39 patients on dialysis 39% had their serum F- concentration above 3.0 microM/l, posing the risk of renal osteodystrophy.      

The effect of ketone bodies on leucine and alanine metabolism in dogs

1. The effect of an infusion of sodium beta-hydroxybutyrate on leucine and alanine metabolism was investigated in dogs starved for 12 h. To determine whether the metabolic changes produced by this infusion were due to the resultant alkalaemia the effect of an equimolar infusion of sodium bicarbonate was also studied. 2. The sodium beta-hydroxybutyrate infusion reduced alanine concentration as a result of a decrease in alanine production rate and an increase in alanine metabolic clearance rate. The sodium bicarbonate infusion induced a small decrease in alanine concentration which was due to an increased metabolic clearance rate. Alanine production rate showed no change. This demonstrates that the fall in alanine concentration after a sodium beta-hydroxybutyrate infusion is due both to a ketone-specific inhibitory effect on alanine production rate and an increased metabolic clearance rate caused by the alkalaemia. 3. Leucine concentration was increased after the ketone infusion due to a small increase in production rate and there was a small increase in the rate of leucine incorporation into protein. Alkalaemia had no effect on leucine concentration or metabolism.     

新疆家畜蠕形蚤病病原研究

本文详细介绍了在新疆发现的花蠕形蚤、叶氏蠕形蚤、北山羊蠕形蚤、羊长喙蚤和狍长喙蚤的形态学特点、地理分布和某些生物学特性。     

Cholinergic amacrine cells of the chicken retina: a light and electron microscope immunocytochemical study

Cholinergic amacrine cells of the chicken retina were detected by immunohistochemistry using an antiserum against affinity-purified chicken choline acetyltransferase. Three populations of cells were detected: type I cholinergic amacrine cells had cell bodies on the border of the inner nuclear and inner plexiform layers and formed a prominent laminar band in sublamina 2 of the inner plexiform layer, while type II cholinergic amacrine cells had cell bodies in the ganglion cell layer, and formed a prominent laminar band in sublamina 4 of the inner plexiform layer. Type III cholinergic amacrine cell bodies were located towards the middle of the inner nuclear layer, and their processes were more diffusely distributed in sublaminas 1 and 3-5 of the inner plexiform layer. Type I and type II cells were present at densities of over 7000 cells/mm2 in central areas declining to less than 2000 cells/mm2 in the temporal retinal periphery. The cells were organized locally in a non-random mosaic, with regularity indices ranging from 3 peripherally to over 5 centrally. Neither at the light nor electron microscopic levels was a lattice of cholinergic dendrites of the kind reported by Tauchi and Masland [J. Neurosci. 5, 2494-2501 (1985)] detectable. Within the two prominent dendritic plexuses, a major feature of the synaptic interactions of the type I and type II cholinergic cells was extensive synaptic interaction between cholinergic processes. Apart from this, there was little, if any, input to cholinergic processes from non-cholinergic amacrine cells, but there was input from bipolar cells. Output from the cholinergic amacrine cell processes was directed towards non-cholinergic amacrine cells as well as other cholinergic amacrine cells, and ganglion cells.