Characterization of biofilm producing methicillin resistant coagulase negative Staphylococci from India.

Methicillin-resistant coagulase-negative staphylococci (MR-CoNS) cause infectious diseases due to their potential to form biofilm and further colonization in hospital materials. This study evaluated the antibiotic susceptible phenotypes, biofilm-producing ability, and biofilm-associated genes (mecA, icaAD, bap, cna, and fnbA). Biofilm formation was detected through Congo red agar (CRA) method and MTP method. The presence of biofilm and associated genes in MR-CoNS were detected by PCR. A total of 310 (55.95%) isolates produced the biofilm. Among these isolates, Staphylococcus haemolyticus (34.83%), Staphylococcus epidermis (31.93%), Staphylococcus capitis (16.77%), Staphylococcus cohnii (10.96%), and Staphylococcus hominis (5.48%) were identified. The antimicrobial susceptibility pattern of CoNS isolates indicated resistance to cefoxitin (100%), erythromycin (94.8%), ciprofloxacin (66.7%), sulfamethoxazole/trimethoprim (66.7%), gentamicin (66.12%), and clindamycin (62.9%). Resistance rate to mupirocin was 48.5% in S. epidermidis and 38.9% in S. haemolyticus isolates. All isolates were sensitive to vancomycin and linezolid. The prevalence rates of icaAD, bap, fnbA, and cna were 18.06%, 12.5%, 47.4%, and 27.4%, respectively. icaAD and bap genes were detected in 18.06% and 12.5% of MR-CoNS isolates. fnbA and cna genes were detected in 47.41% and 27.41% of MRCoNS isolates. icaAD positive strains exhibited a significant increase in the biofilm formation compared with those that lacked icaAD (0.86 (0.42, 1.39) versus 0.36 (0.14, 0.75), respectively; P < 0.001). In conclusion, the majority of MR-CoNS isolates were biofilm producers, and S. capitis, which possessed icaAD genes, ranked as the great biofilm producer than other Staphylococcus. The study's findings are important to form a strategy to control biofilm formation as an alternative strategy to counter the spread of MR-CoNS in healthcare settings.

Antidiabetic effects of Mukia maderaspatana and its phenolics: an in vitro study on gluconeogenesis and glucose uptake in rat tissues.

CONTEXT: Traditional medicine is used by over 60% of the world's population for health care. Mukia maderaspatana (L.) M. Roem. (Cucurbitaceae) (Mukia) is extensively used in folklore medicine as an antidiabetic plant. It is rich in phenolics that contribute to its medicinal properties. OBJECTIVE: Mukia extract and phenolics such as quercetin and phloroglucinol are investigated for their in vitro antidiabetic activity. MATERIALS AND METHODS: Quercetin, phloroglucinol, and methanol extract of the dried whole plant (0.25 and 0.5 mg/ml) were studied for the inhibition of gluconeogenesis in rat liver slices and glucose uptake in isolated rat hemi-diaphragm (50 and 100 µg/ml). Phenolics of Mukia were analyzed by HPLC. RESULTS AND DISCUSSION: Glucose (1.2 mg/g/h) was synthesized from pyruvate and the synthesis was completely inhibited by insulin (1 U/ml). Quercetin at 0.25 and 0.5 mg/ml caused 65% and 89% inhibition (0.42 mg/g/h and 0.13 mg/g/h glucose). Addition of insulin did not increase inhibition. Phloroglucinol inhibited 100% glucose production with or without insulin. Mukia (0.25 mg/ml) inhibited gluconeogenesis (0.65 mg/g/h) by 45%, and with insulin, inhibition increased to 50% (0.59 mg/g/h). At 0.5 mg/ml, glucose production was stimulated by1.2-fold, but with insulin it was inhibited by 89% (0.13 mg/g/h glucose). Mukia had no effect on glucose uptake, but potentiated the action of insulin mediated glucose uptake (152.82 ± 13.30 mg/dl/g/30 min) compared with insulin control (112.41 ± 9.14 mg/dl/g/30 min) (p < 0.05). HPLC analysis revealed the presence of phenolics. CONCLUSION: Results provide scientific rationale for the use of Mukia in folk medicine as an antidiabetic nutraceutical.

Hydrogen sulfide promotes nitric oxide production in corpus cavernosum by enhancing expression of endothelial nitric oxide synthase.

Recently, hydrogen sulfide (H2S) has been identified as a potential therapy for ED. However, a thorough understanding of its molecular mechanisms of action would be essential to develop H2S as a new therapy for ED. In this study, the effect of H2S on nitric oxide (NO) production, especially through the expression of constitutive nitric oxide synthase (NOS) isoforms-endothelial NOS (eNOS) and neuronal NOS (nNOS) in rat corpus cavernosum (CC) were explored. Real-time PCR studies subsequent to in vitro treatment of sodium hydrosulfide hydrate (NaHS), a stable H2S donor, showed increases in eNOS but not nNOS mRNA. Western blot studies confirmed that the exogenously applied NaHS increased eNOS but not nNOS protein expression in the rat CC. Furthermore, NaHS did not alter the expressed amounts of Caveolin-1 (CAV-1), a dominant inhibitory interaction partner of eNOS, in these tissues. Not surprisingly, NaHS also enhanced the NO production in eNOS-associated membrane fraction of rat CC. Taken together, we ascertain that H2S could exert its proerectile effects by augmenting NO pathway. It appears that H2S would be particularly useful in improving the clinical outcome of ED patients, whose erectile impairment is due to an inherent attenuation of the endothelial NO formation in the cavernosum.

Efficacy of red clover isoflavones in the menopausal rabbit model.

OBJECTIVE: To evaluate the effectiveness of phytoestrogens as alternatives for selective dysfunctional changes in the menopausal rabbit model. DESIGN: Prospective, vehicle-controlled experimental study. SETTING: Reproductive pharmacology laboratory in a university department. ANIMAL(S): Twenty-four rabbits with experimentally induced menopause and six intact controls. INTERVENTION(S): Surgical menopause was induced in 24 rabbits by ovariectomy. After 4 weeks of convalescence, three groups (n = 6) were given 100 microg/kg E(2) valerate, 100 microg/kg daidzein, or 6.68 mg/kg red clover extract daily for 12 weeks. The remaining six rabbits served as the operated control group. MAIN OUTCOME MEASURE(S): Vaginal blood flow using Doppler flowmetry, before, during, and after pelvic nerve stimulation; and measured parameters of uterine weight, femoral bone density, clitoral cavernosal histology, and hormone levels. RESULT(S): After pelvic nerve stimulation, blood flow increased remarkably in the daidzein-treated group. Serum E(2) and uterine weight increased significantly in the estrogen group. Cavernosal structure was well preserved in all three treatment groups, and bone mineral density was lowest in ovariectomized controls (0.3467 g/cm(2)) and highest in the red clover (0.4012 g/cm(2)) groups. CONCLUSION(S): Supplementing isoflavones for menopause leads to significant improvements in bone density, tissue integrity, and vaginal blood flow with minimal effect on uterine weight and may therefore be a viable alternative to conventional regimens using synthetic estrogens.

Relevance of oestradiol-testosterone balance in erectile dysfunction patients' prognosis.

INTRODUCTION: The ageing process in man is accompanied by a number of endocrine changes including decline in testosterone (T), physiological imbalance between androgen and oestradiol (E2) and changes in the E2-T ratio. In this study, hormone profile data from a group of erectile dysfunction (ED) patients were reviewed to evaluate its impact on ED, with emphasis on oestradiol derangement. METHODS: 30 ED patient case notes with a record of hormone profiles were retrospectively reviewed. Laboratory investigation included levels of total testosterone, total oestradiol, prolactin, luteinising and follicle stimulating hormones, in addition to lipid profile and glucose, based on specific history. These patients were divided into two groups based on the history of presence (Group A) or absence (Group B) of adequate sexual desire. RESULTS: In Group B patients, the E2-T derangement with increasing age was statistically significant with lower serum T level (2.6 ng/ml; range, 1.6-3.7 ng/ml) and elevated E2 level (60 pg/ml; range, 40-120 pg/ml). CONCLUSION: In this preliminary report, although low total testosterone level is seen together with impaired libido and erectile impairment, the accompanying significant increase in E2 indicates the possible role for oestrogen in causation and/or persistence of ED in this group of patients.

Characterization of hypertriglyceridemia-induced erectile dysfunction.

OBJECTIVES: To characterize the effects of experimental hypertriglyceridemia on erectile function. METHODS: The daily water intake of 40 sexually mature male rats (groups II to V) was supplemented for 12 weeks with 10% fructose solution to induce hypertriglyceridemia. In addition, animals from three groups (III, IV, and V) were given through daily oral gavage metformin (group III), fenofibrate (group IV), and fish oil (group V) to estimate their therapeutic effects on fructose-induced metabolic alterations. Another group (I) of 10 rats served as controls. At 12 weeks, changes in sexual behavior and cavernous pressure response to nerve stimulation were correlated with serum triglyceride levels and response to preventive measures. RESULTS: After administration of 10% fructose, triglyceride levels increased fourfold to 1.79 +/- 0.31 mmol/L (mean +/- standard deviation) (group II). Coinciding with this elevation was a significant impairment of the copulatory pattern, with prolongation of mount (3.70 +/- 3.44 minutes), intromission (7.09 +/- 4.49 minutes), and ejaculatory latencies and reduced intracavernous pressure (27.56 +/- 2.04 mm Hg) response to nerve electrical stimulation. Whereas similar significant impairment was seen in group III, the other two groups (IV and V) showed beneficial effects of triglyceride reduction on these parameters. CONCLUSIONS: Our results provide the first evidence for an impact of triglycerides on erectile function. This detrimental effect is likely to be due to functional vascular and neuronal deficits related to hypertriglyceridemia.

Estrogen and phytoestrogen predispose to erectile dysfunction: do ER-alpha and ER-beta in the cavernosum play a role?

OBJECTIVES: To investigate the functional changes in rabbit penile corpus cavernosum (CC) secondary to experimental hyperestrogenism and attempt to identify sites of immunoexpression for estrogen receptor subtypes alpha and beta (ER-alpha and ER-beta) in the CC. Although the role of testosterone in sexual function has been extensively studied in clinical settings and experimental animal models, the effect of hormonal modulation/imbalance arising from estrogenic excess has not been characterized. METHODS: Eighteen New Zealand white male rabbits (2.5-3.0 kg) were divided into control and two treatment groups. The two treatment groups were given orally 0.1 mg of estradiol valerate (estradiol group) or phytoestrogen, daidzein (phytoestrogen group) daily for 12 weeks. Blood and tissue samples were collected for hormone levels and in vitro pharmacologic studies. CC samples from untreated rabbits (n = 4) were cryosectioned and incubated with appropriate mouse monoclonal antibody for identification of ER-alpha and ER-beta. RESULTS: Through immunohistochemistry, color signals for nuclear ER-alpha and ER-beta receptors were localized within the CC. Chronic treatment with estradiol and phytoestrogen significantly reduced the systemic total testosterone levels. In organ bath experiments, relaxant responses to acetylcholine, nitroglycerin, and nitrergic transmission were significantly attenuated compared with the control response. With regard to the contractile effect, both types of estrogen treatments significantly potentiated norepinephrine-induced antierectile contraction of the CC. CONCLUSIONS: These results indicate that estradiol treatment and chronic exposure of phytoestrogen may cause receptor-mediated pathophysiologic changes in erectile function, leading to erectile dysfunction.

Oestrogen-androgen crosstalk in the pathophysiology of erectile dysfunction.

Ageing in man is associated with a decline in testosterone following changes in the hypothalamo-pituitary-testicular axis. This may offset the physiologic equilibrium between oestrogen and androgen and at some point when the ratio of free testosterone to oestradiol reaches a critical level, the oestrogenic gonadotropin suppressive effect predominates with decreased release of FSH and LH. Adding to this endocrinal complexity is the continued peripheral conversion to oestradiol through aromatisation. Although the androgen deficiency is not the sole cause for impotence in the elderly, there is a gradual decrease in nocturnal penile tumescence (NPT) and spontaneous morning erections with ageing. Despite the age related increase in oestrogen levels, the information on the pathophysiological role of the "female hormone" in erectile dysfunction has been scanty. Together with our identification of oestrogen receptors within the penile cavernosum, we have delineated dysfunctional changes on male erection mediated by oestradiol. These findings parallel the recent concerns over environmental oestrogens on fertility declines in young men. Oestrogenic activity is also present in plants and thereby in human diet. These phytoestrogens are structurally and functionally similar to oestradiol and more potent than the environmental oestrogenic chemicals such as organochlorine and phenolic compounds. Thus in the light of growing concerns of possible compromising effects on sexuality by endogenous and environmental oestrogens, we are faced with the scientific need to delineate their role on the mechanism of male erectile pathway in health and disease for clinical correlates and prognostics.

Oestrogen-mediated hormonal imbalance precipitates erectile dysfunction.

Declining testosterone (T) in an aging male offsets the equilibrium between androgen and oestrogen (oestradiol, E(2)) with a resultant increase in E(2)-T ratio. Similar functional hormone imbalance is existent in clinical states of hypogonadism and is likely to arise from exposure of males to environmental oestrogens. The pathophysiological significance of this derangement on erectile function, hitherto unknown, was estimated in sexually mature male rats following acute and chronic treatment with oestrogen. A total of 60 male Sprague-Dawley rats (200-250 g) were divided into control and two treatment groups, administered 0.01 and 0.1 mg of oestradiol through oral gavage daily for 1 week (n=30, acute study) and 12 weeks (n=30, long-term study), respectively. Sexual activity in the presence of hormonally primed female rats and intracavernous pressure (ICP) response to electrical stimulation estimated treatment-induced changes, which were correlated with hormone levels and penile morphology at 12 weeks. Following two to five-fold elevation in serum E(2) levels (and simultaneous reduction in testosterone), there was a significant prolongation of mount, intromission, ejaculation latencies and some decrease in frequencies. The ICP response to nerve stimulation was also impaired in all the treated groups. Histologically, trichrome staining highlighted the cavernosal connective tissue hyperplasia in the long-term study groups. Results of this investigation indicate that oestradiol causes pathophysiological changes in erectile function. These observations provide an indirect evidence for the possible sexual health hazards in man upon inadvertent exposure to environmental oestrogens, ageing and derangement of E(2)-T ratio.

Elevated low-density lipoprotein cholesterol (LDL-C) enhances pro-erectile neurotransmission in the corpus cavernosum.

Hypercholesterolaemia is thought to foster atherosclerosis and impotence through its effects on vascular endothelium. In this study, we investigated the pharmacological changes in rabbit corpus cavernosum (CC) secondary to incubation with lysolecithin and hypercholesterolaemia. A daily egg yolk dietary supplement induced gross hypercholesterolaemia in our rabbits. Group A of test animals (n-12) was fed with the yolk content of single egg and group B (n-6), that from two eggs for eight weeks. Serum level estimation revealed a progressive elevation of cholesterol to 15 and 30 times respectively, in the two treated groups as compared to values in the control group (n-6). Early histological manifestations of atherosclerosis were perceived as fat cell lesions in the cavernosum of treated animals. In vitro pharmacological studies on CC strips from both groups of test animals demonstrated a profound accentuation of the contractile responses to noradrenaline and histamine and attenuation of relaxant response to acetylcholine. However, in contrast to single-egg treated group, which demonstrated a reduction in the relaxant response to electrical field stimulation (EFS), there was a marked and statistically significant potentiation of this nitrergic transmission, in the two-eggs group. Prior incubation of CC strips of normolipidaemic rabbits (n-7) with lysolecithin, reproduced similar exaggerated response to EFS. Therefore, from the results of our study, it is concluded that oxidised LDL or its major amphiphile lysolecithin, at some critical level or beyond, may be capable of reverting at least some of the adverse effects of hypercholesterolaemia on erectile function, through its mediating effect on nitrergic transmission.

Sexual dysfunction related to antihypertensive agents: results from the animal model.

The present investigation elucidates the deleterious effects of three prototypical antihypertensive drugs namely, propranolol, clonidine and captopril on the erectile physiology. In order to delineate the direct drug effects from vascular insufficiency inherent in hypertensive states, the study was conducted on a normotensive animal model. The adverse effects of these drugs were estimated as changes in sexual behaviour and intracavernous pressure response of electrical stimulation in the treated rats compared to normal age-matched controls (n = 10, each group). Copulation studies indicated significant impairment of sexual function in the groups on propranolol and clonidine. The cavernous pressure response to nerve stimulation at the end of sixteen weeks further reinforced the gross compromise on sexual function in these two treated groups. In contrast, the captopril administration produced only marginal alterations to the responses recorded. The results from this study clearly indicate that propranolol and clonidine interfere with sexual behaviour and nerve mediated response to erection whereas captopril which is devoid of significant effects on these parameters, may be a better therapeutic option.

Effects of feeding egg yolk on the serum lipid levels in rabbits.

Healthy, nonobese, young rabbits developed hypercholesterolemia following daily intake of fresh egg yolk for 8 weeks. On a quantitative basis, this diet had a profound effect on serum cholesterol level which rose to 15 or 30 times the baseline value depending on whether the test group consumed the yolk content of one or two eggs during the study. Similar drastic changes observed in low density lipoprotein cholesterol levels in these test animals make this a useful method for defining the early pathological changes of atherosclerosis in man. In addition, the present study provides direct evidence of the deleterious effect of hen's egg yolk on the serum cholesterol level in an appropriate and easily reproducible animal model.