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.     

Alterations in glucose transporter proteins in alcoholic liver disease in the rat.

We used the intragastric feeding rat model for alcoholic liver disease to investigate alterations in glucose transporter isoforms GLUT 1 and GLUT 2 in response to different dietary fats and ethanol. Six groups of rats (three rats/group) were fed ethanol or dextrose with either saturated fat, corn oil, or fish (menhaden) oil. All control animals were pair fed the same diets as ethanol-fed rats except that ethanol was isocalorically replaced by dextrose. In all animals, the following were assessed: pathological changes in the liver, immunohistochemical and Western blot analysis of GLUT 1 and GLUT 2 isoforms, and glycogen distribution. The most severe pathological changes were seen in fish oil/ethanol fed rats, moderate changes were seen in the corn oil/ethanol group and no changes were observed in the dextrose-fed or saturated fat/ethanol groups. In the groups of rats showing pathological liver injury (corn oil/ethanol and fish oil/ethanol), the depletion in liver glycogen was accompanied by decreased GLUT 2 expression and increased GLUT 1 expression. A decrease in glycogen and GLUT 2 expression was also seen in the fish oil/dextrose-fed rats. We hypothesize that the shift in glucose transporters from GLUT 2 to GLUT 1 probably reflects a compensatory response to attenuated gluconeogenic activity and to meet the increased intracellular demand for glucose. This demand for glucose in the presence of depleted glycogen may serve to provide a source for ATP synthesis in the centrilobular zone where hypoxia occurs secondary to ethanol metabolism.     

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.     

Use of total cholesterol/albumin ratio as an alternative to high density lipoprotein cholesterol measurement.

In a study of apparently healthy males, we noted a correlation between serum albumin and high density lipoprotein cholesterol (HDL-C) (r = 0.32, p less than 0.001). We then correlated the total cholesterol:albumin ratio (TC:Alb) with the TC:HDL-C ratio (r = 0.89, p less than 0.001). We used the TC:Alb ratio to determine whether this was better than TC by itself in predicting whether an individual had a TC:HDL-C ratio of less than or greater than or equal to 5. The ratio performed better than TC and correctly classified 89% of individuals (66% with TC) (p less than 0.001). Since measurements of TC and Alb are routinely available on multichannel analysers, use of this ratio would provide a less expensive alternative to HDL-C measurement.     

川芎嗪诱导大鼠骨髓间质干细胞分化为神经元样细胞的研究

目的用川芎嗪(ligustrazin hydrochloride)在体外定向诱导SD青年鼠骨髓间质干细胞(mesenchymal stem cells，rMSCs)分化为神经元样细胞。方法用低糖DMEM冲洗骨髓腔，收集骨髓细胞悬液，接种在塑料培养瓶中。经体外扩增、纯化，选用第5代后的骨髓间质干细胞进行诱导分化。用10μg／LbFcF预诱导24h，更换成含川芎嗪的无血清培养基DMEM诱导间质干细胞分化为神经元样细胞。用免疫组织化学SABC法鉴定神经丝蛋白(NF—M)、神经元特异性烯醇化酶(NSE)、巢蛋白(nestin)、微管联合蛋白-2(MAP-2)、生长相关蛋白-43(GAP-43)、胶质纤维酸性蛋白(GFAP)的表达。结果第5代间质干细胞形态达到均一，呈梭形。用川芎嗪诱导15min到3h，间质干细胞胞体逐渐增大，并伸出细长突起形似神经元样细胞。免疫组织化学显示NF-M、NSE、nestin、MAP-2和GAP-43表达阳性，而GFAP阴性。对照组上述染色均为阴性。结论川芎嗪可诱导骨髓间质干细胞分化为神经元样细胞。     

Androgen receptor YAC transgenic mice carrying CAG 45 alleles show trinucleotide repeat instability

X-linked spinal and bulbar muscular atrophy (SBMA) is caused by a CAG repeat expansion in the first exon of the androgen receptor (AR) gene. Disease-associated alleles (37-66 CAGs) change in length when transmitted from parents to offspring, with a significantly greater tendency to shift size when inherited paternally. As transgenic mice carrying human AR cDNAs with 45 and 66 CAG repeats do not display repeat instability, we attempted to model trinucleotide repeat instability by generating transgenic mice with yeast artificial chromosomes (YACs) carrying AR CAG repeat expansions in their genomic context. Studies of independent lines of AR YAC transgenic mice with CAG 45 alleles reveal intergenerational instability at an overall rate of approximately 10%. We also find that the 45 CAG repeat tracts are significantly more unstable with maternal transmission and as the transmitting mother ages. Of all the CAG/CTG repeat transgenic mice produced to date the AR YAC CAG 45 mice are unstable with the smallest trinucleotide repeat mutations, suggesting that the length threshold for repeat instability in the mouse may be lowered by including the appropriate flanking human DNA sequences. By sequence-tagged site content analysis and long range mapping we determined that one unstable transgenic line has integrated an approximately 70 kb segment of the AR locus due to fragmentation of the AR YAC. Identification of the cis - acting elements that permit CAG tract instability and the trans -acting factors that modulate repeat instability in the AR YAC CAG 45 mice may provide insights into the molecular basis of trinucleotide repeat instability in humans.      

Comparison of hospital staff performance when using desk top analysers for "near patient" testing.

The quality and reliability of four desk top analysers were evaluated. In the context of an outpatient clinic, intensive care unit, and a mock up of a physician's office. Seventeen nurses, 14 physicians, and 12 medical office personnel took part in the study. The instruments and tests evaluated were Reflotron (glucose, cholesterol, triglycerides, gamma-glutamyl transferase), Seralyzer (creatinine, glucose, potassium, aspartate aminotransferase), Vision (glucose, (creatinine, glucose, potassium, aspartate aminotransferase), Vision (glucose, urea, cholesterol, triglycerides alkaline phosphatase, uric acid), and DT60 (sodium, potassium, glucose, amylase, uric acid and creatinine). Of the 320 tests performed on the Vision, only two differed by more than 10% between the specialist staff and other groups. For those performed on the Seralyzer, 95 of 254 results differed by more than 10%, 19 of 199 by more than 10% for the Reflotron, and 50 of 318 by more than 10% for the DT60. In general, the nurses were more adept at using the analysers than the physicians and medical office personnel.     

Near-patient testing. Quality of laboratory test results obtained by non-technical personnel in a decentralized setting

The authors evaluated the quality and reliability of four desktop analyzers in the outpatient clinic. Twenty-seven nontechnologists (NTs) participated in the study. These included nurses, physicians, and medical students. The instruments and tests evaluated were as follows: Reflotron (glucose, cholesterol, triglycerides, gamma-glutamyltransferase and urea); Seralyzer (creatinine, glucose, potassium, aspartate aminotransferase, and hemoglobin); Vision (glucose, urea, cholesterol, triglycerides, alkaline phosphatase, and uric acid); and DT60 (sodium, potassium, glucose, amylase, uric acid, bilirubin, and creatinine). For precision studies, low and high control material was used, and method comparison was done with methods in routine use in the laboratory. The range of coefficients of variation (CVs) for the analyzers with NTs was as follows: Reflotron: CV, 2.4-7.9%; Seralyzer CV, 1.4-18.7%; Vision: CV, 1.5-2.7%; DT60: CV, 2.5-46.8. The percentage results that is different by greater than 10% between the NTs and trained technologists was related to the complexicity of procedure for each analyzer and was the lowest for the Vision analyzer and greatest for the Seralyzer.