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.     

Anti-inflammatory activity of substituted 1,3,4-oxadiazoles

Various 2-(4-biphenoxymethyl)-5-arylamino-1,3,4-oxadiazoles were synthesized by cyclization of the corresponding 1-(4-biphenoxyacetyl)-4-substituted thiosemicarbazides. These compounds were characterized by their elemental analyses and infrared, mass, and nuclear magnetic resonance spectral data. All substituted thiosemicarbazides (100 mg/kg, ip) and cyclized substituted oxadiazoles (100 mg/kg, ip) possessed anti-inflammatory activity, as reflected by their ability to provide protection against carrageenin-induced edema in the rat paw which ranged from 28 to 68% and 36 to 76%, respectively. Cyclization of the substituted thiosemicarbazides, in general, resulted in an increase in the anti-inflammatory activity of their corresponding substituted oxadiazoles, with the exception of those containing 2,4-dimethyl and 3,4-dimethyl substituents in their molecular structure. Hydrocortisone (10 mg/kg, ip) and oxyphenbutazone (40 mg/kg, ip) were used as the standard reference drugs and these provided 45 and 53% protection, respectively. All compounds (1 mM) possessed antiproteolytic activity and the in vitro inhibition of trypsin-induced hydrolysis of bovine serum albumin ranged from 13 to 75% for substituted thiosemicarbazides and 39 to 70% for substituted oxadiazoles. There was no relationship between the anti-inflammatory activity of substituted thiosemicarbazides and substituted oxadiazoles and their antiproteolytic effectiveness. The low toxicity of these compounds was reflected by their high approximate LD50 values, ranging from 500 to 1000 mg/kg.     

Experimental scoliosis in the rat. II. Biomechanical analysis of the forces during Harrington distraction

The purpose of this study was to characterize the forces resulting from Harrington distraction of the spine in an experimental model of scoliosis in the rat, in order to establish both the similarity of this model to human scoliosis and identify potential force parameters that may be useful for clinical decision-making. Harrington distraction was performed in 36 rats that had been made scoliotic 9-12 weeks earlier by the method described in the previous paper. Distractions were carried out in discrete and timed steps until separation of the vertebral laminae (mechanical failure) occurred at the upper hook site. Distractive forces were monitored continuously by a strain gauge mounted on the tension side of the upper arm of the outrigger. The resulting data were compared among the various curvature groups. The relationship between the length of distraction and the maximum force produced was similar for all animals regardless of curvature. This relationship was quadratic and was characterized by an inflection point where forces increased rapidly with each distraction. The amount of distraction necessary to reach both the inflection and failure points differed only for curves above 100 degrees. The amount of force required to reach failure was lower for curves above 75 degrees. Curves above 50 degrees had a lower percent correction at the inflection point. Bending and tensile forces were calculated by vector analysis. Axial load efficiencies were greater for curves above 50 degrees, as evidenced by increased bending forces in these animals. The viscoelasticity of the spine decreased after inflection in all animals.(ABSTRACT TRUNCATED AT 250 WORDS)     

Application of a new transport and storage material for improving the quality of drinking water in rural African areas]

Although boreholes in rural african areas deliver safe drinking water, there is a daily consumption of water polluted by fecal bacteria. Contamination occurs during transport, storage and domestic allocation of water. This is directly attributable to ignorance of the rules of hygiene, and the use of traditional jars ineffective in maintaining water quality. Their replacement with more modern recipients and the initiation of sanitary education markedly decrease bacterial water contamination, however, WHO standards which define portable water are rarely attained. In fact, it seems that established WHO conditions can only be achieved with piped water or after chemical disinfection.