Causative organisms in microbial keratitis, their sensitivity pattern and treatment outcome in western Nepal.

INTRODUCTION: Corneal infection is one of the major causes of monocular blindness in developing countries. OBJECTIVE: To determine the epidemiological characteristics, predisposing factors, microbiological pattern, sensitivity pattern and treatment outcome of microbial keratitis. MATERIALS AND METHODS: A retrospective analysis of hospital records of 414 patients with diagnosed infective keratitis was done. The outcome measures were microbial isolates, their sensitivity to therapeutic agents and treatment outcome. RESULTS: Of the total, 312 (75.4 %) patients were farmers by profession, 138 (33.3 %) had a history of ocular trauma and 17(4.1 %) were using topical corticosteroids. Among the 138 cases of the corneal ulcer with trauma, 52 (37.68 %) had fungi isolated in culture (RR=0.54, 95% CI = 0.44 - 0.68) and 32 (23.19 %) had a bacterial growth. Cultures were positive in 300 (72.5 %) cases, having 138 (33.3 %) patients with pure fungal infection, 121 (29.2 %) with pure bacterial and 41 (9.9 %) with mixed infection. Fusarium spp was the most common fungal pathogen while Staphylococcus epidermidis was the commonest bacterial isolate. The most sensitive antibiotics for the Gram positive bacteria was cephazolin (84.92 %), while for Gram negative, ciprofloxacin and ofloxacin were the most effective (79.31 %). Of 414 cases of corneal ulcers, 363 (87.7 %) cases healed completely. CONCLUSION: Microbial keratitis is mostly seen in farmers in this part of the world. Fusarium and Staphylococcus epidermidis were the most common isolates. Cephazoline and ofloxacin were the most effective antibiotics for Gram positive and Gram negative organisms respectively.

Molecular cloning and characterization of cDNA encoding buffalo (Bubalus bubalis) cytochrome P450 aromatase in the ovary.

One of the predominant causes of poor reproduction in buffaloes is low levels of ovarian estrogens. A rate limiting enzyme in estrogen biosynthesis is cytochrome P450 aromatase (P450 AROM), the product of CYP19 gene. In the present study CYP19 cDNA was cloned and its 5'UTR was characterized by 5'RACE in granulosa cells of large follicles. CYP19 transcripts with four different 5'UTRs (206, 114, 90 and 3 bases) were found in buffalo granulosa cells of large ovarian follicles. Interestingly, a predominant aromatase transcript with short 5'UTR (3 nucleotides) was found. Further studies are required to understand the relevance of these transcripts and their translational efficiency in granulosa cells of large follicles during folliculogenesis of buffalo ovary.

Mechanism delineating differential effect of an antiestrogen, tamoxifen, on the serum LH and FSH in adult male rats.

Tamoxifen, a synthetic non-steroidal antiestrogen with residual estrogenic activity, administered to adult male rats reduces their fertility. A decrease in the circulating LH and testosterone levels with a transient rise or no change in circulating FSH levels was observed. The present study was carried out to delineate the mechanism causing the differential effect of tamoxifen on circulating gonadotropins by correlating it to changes in the hypothalamic LHRH, pituitary gonadotropins and testicular inhibin/activin. Hypothalamus, pituitary-hypothalamus complex (PHC) and intact pituitary (PI) from control and tamoxifen-treated male rats were superfused in vitro, and pulsatile release of LHRH by hypothalamus and that of LH and FSH by the PHC and PI were studied. Concomitantly, testicular immunoexpression of alpha and betaB subunits of inhibin/activin were studied by immunohistochemistry and enzyme-linked immunosorbent assays (ELISA). At 0.4 mg/kg/day dose of tamoxifen a decrease in mean hypothalamic LHRH and LH pulse frequency from PHC construct was observed. FSH pulse frequency was not affected under the same experimental conditions. At the same dose of tamoxifen, testicular expression of both alpha and betaB subunits of inhibin/activin was upregulated. The study demonstrated that reduced circulating LH levels were due to a decrease in hypothalamic LHRH concentration and in LH pulsatility following tamoxifen treatment. The lack of effect on circulating FSH under the same experimental conditions was likely due to its modulation by inhibin and activin.

Anti-inflammatory activity of alkanoids and triterpenoids from Trichodesma amplexicaule Roth.

The phytochemical investigation of Trichodesma amplexicaule guided by bioassay, to isolation of triterpenoids and aliphatic phytoconstituents. To evaluate the anti-inflammatory activities of isolated phytoconstituents, models with carrageenan-induced acute arthritis and complete Freund's adjuvant (CFA)-induced chronic arthritis in rats were conducted. The investigated results showed that alkanoic acid significantly inhibited the carrageenan-induced acute arthritis. Moreover, alkane also supressed the development of chronic arthritis induced by CFA. It has been reported that alkane was the major phytoconstituent (1.03 +/- 0.00135%) in in vivo studies.

Antifertility effects of fluphenazine in adult male rats.

The underlying mechanisms in human infertility associated with hyperprolactinemia have yet to be established. Hyperprolactinemia is a known side-effect of fluphenazine, a broad spectrum, long-acting phenothiazine known to be D2 dopamine receptor antagonist. Dose-related effects of fluphenazine decanoate were ascertained on the fertility of 60-day treated, adult male rats. Significant increase in the serum levels of prolactin and decrease in the levels of LH and FSH were seen at doses of 1-3 mg/kg/day. No effect was evident on the serum testosterone (T) and estradiol. The tissue levels of Inhibins were not affected. The weights of testes, epididymides, seminal vesicles, ventral prostate, adrenal and pituitary glands were not affected. Testicular histology showed sloughing indicating the sensitivity of this parameter to FSH deficiency. Mating occurred within 10 days of cohabitation in the control and 1-2 mg/kg/day treated groups but delayed in the 3 mg/kg/day treated group with a significant effect on potency. Implantation sites, litter size and fertility index were significantly reduced at 2-3 mg/kg/day doses of fluphenazine. No effects however were seen on sperm counts or motility whereas morphological changes were apparent in the acrosome. Chromatin decondensation in vitro was enhanced and sperm chromatin structure assay revealed DNA denaturation. Hypothalamic tyrosine hydroxylase levels were increased in 1-3 mg/kg/day dose range. Hyperprolactinemic males sired fewer pups as compared to controls. Hypothalamic tyrosine hydroxylase was upregulated at all the doses. The antifertility effects of fluphenazine-induced hyperprolactinemia appeared to be unrelated to testosterone (T). In addition, FSH decrease might have affected the intrinsic sperm quality and thereby reduced litter size.

Anti-inflammatory activity of shikonin derivatives from Arnebia hispidissima.

Arnebia hispidissima ethanolic extract, after chromatography, yielded a number of shikonin derivatives, which were identified as arnebin-5, arnebin-6, teracryl shikonin, arnebinone and acetyl shikonin. All these compounds were firstly reported from this plant species and evaluated to the anti-inflammatory activity of ethanolic extract and isolated shikonin derivatives, models with carrageenan-induced paw edema and complete Freund's adjuvant (CFA)-induced chronic arthritis in rats were conducted. The observed results indicated that pre-treatment with arnebinone significantly inhibited the carrageenan-induced paw edema and also suppressed the development of chronic arthritis induced by CFA.

Anti-inflammatory and antimicrobial activities of triterpenoids from Strobilanthes callosus nees.

The anti-inflammatory and antimicrobial activities of the 95% ethanol extract, benzene fraction and isolated triterpenoids of Strobilanthes callosus were investigated. In the carrageenan-induced paw edema inflammation model, the taraxerol showed a high reduction of edema, but the antimicrobial effect observed was lower at the two doses employed. These results confirm the use of this plant in folk medicine as an anti-inflammatory and antimicrobial herbal drug.

Modulation of pituitary gonadotropins and prolactin secretion by testosterone in vitro.

Investigations were undertaken to study the differential modulation of LH, FSH and PRL secretion by testosterone (T) using whole pituitary (PI) or pituitary-hypothalamus coincubates (PHC) as in vitro constructs. PI and PHC from intact and castrated rats were incubated with or without T thrice, for 24 h each, (24 h x 3, total incubation period 72 h). The spent media was replenished every 24 h. At the end of 72 h, a few of the pituitary glands were challenged with 10 nM LHRH for 4 h. The spent media and pituitary glands were analyzed for LH, FSH and PRL using specific RIAs. Incubation of PI or PHC from intact rats with T stimulated the release of LH and FSH but inhibited the release of PRL. T had no effect on the intrapituitary contents of LH but inhibited intrapituitary contents of FSH and PRL, as compared to controls incubated without T. Castration increased intrapituitary contents of LH and FSH with concomitant decrease in PRL levels. Incubation of PI or PHC from castrated rats with T inhibited intrapituitary contents of LH to intact pituitary levels, while PRL levels were further reduced instead of being ameliorated. It is concluded that PI or PHC can be used as convenient in vitro models to monitor the effect of castration or of T modulation of pituitary and hypothalamus functions. T does not affect the synthesis of LH at the gonadotroph level but facilitates the regulation of intracellular LH and FSH levels. It is postulated that T inhibits the synthesis of FSH/PRL at the gonadotroph/lactotroph levels.

Cerebrospinal fluid and blood concentrations of luteinizing hormone, follicle stimulating hormone and prolactin following castration of adult male rats.

Comparative levels of LH, FSH, and PRL in the serum and cerebrospinal fluid (CSF) of adult male rats were studied at different periods following castration. Intact and sham-operated animals served as controls. Blood and CSF were collected at 1, 3, 7, 14, 21, 28, 35 and 46 days following castration. The CSF was collected via cisterna-magna puncture, while the blood was collected from abdominal aorta. Serum gonadotropins increased progressively beginning day 1 post-castration to reach maximum by day 35 or 46 post-castration. Sham operation and castration did not affect mean CSF, LH and FSH levels compared to intact controls. Analysis of the temporal pattern of serum and CSF gonadotropin levels following castration revealed significant positive correlation between CSF and serum LH (r = 0.58) and FSH (r = 0.64) levels respectively. The data suggest that CSF gonadotropins may be derived from systemic circulation. Serum PRL levels were not affected by castration, but CSF PRL levels were significantly reduced at days 28, 35 and 46 post-castration compared to intact controls. CSF PRL levels showed negative correlation with serum LH and FSH levels but failed to show a correlation with serum PRL levels. Hypothalamic norepinephrine turnover rate increased at days 28, 35 and 46 post-castration. Hypothalamic dopamine contents and turnover rates were reduced at days 21 and 28 post-castration. It is suggested that CSF PRL may have a role in the regulation of serum gonadotropins.