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Biomedical subjects

V Srikanth

Publications and source records attributed to V Srikanth.

12 recordsLinked to original sources
PubMed2007

The association between non-melanoma skin cancer and osteoporotic fractures--a population-based record linkage study.

UNLABELLED: We studied the association between osteoporotic fractures and prior non-melanoma skin cancer (NMSC, a biomarker for cumulative sun exposure). The risk of prior NMSC in our fracture cohort was significantly reduced (standardised incidence ratio 0.69, 95% CI 0.61, 0.78). Adequate lifetime sun exposure may be necessary to protect against osteoporotic fractures in later life. INTRODUCTION: The relationship between cumulative sun exposure and osteoporotic fractures is uncertain. We aimed to study the association between non-melanoma skin cancer (NMSC), a marker of cumulative sun exposure, and osteoporotic fractures in an older cohort. METHODS: A retrospective cohort study in southern Tasmania in people aged at least 50 years with incident radiographic fracture (n = 2,283) was carried out. By record linkage to the Tasmanian Cancer Registry the cohort was followed backwards through time until the occurrence of NMSC or end-of follow-up. Relative risk was estimated by the standardised incidence ratio (SIR) using sex-, age- and calendar year-specific cancer incidence rates in southern Tasmania as reference. RESULTS: The incidence of prior NMSC in the fracture cohort was 31% lower than for the general population (SIR 0.69, 95% CI 0.61, 0.78). This effect was significant for most fracture subtypes except pelvic and wrist fractures and observed for both NMSC subtypes, squamous cell carcinoma and basal cell carcinoma. CONCLUSIONS: Older people with osteoporotic fractures may have had lifestyles linked to lower cumulative sunlight exposure. Achieving a balance between adequate lifetime sun exposure and protection against its adverse effects (such as fractures and skin cancer) may require assessment of individual risks.

Age Distribution↗
PubMed2006

Falls risk is associated with pain and dysfunction but not radiographic osteoarthritis in older adults: Tasmanian Older Adult Cohort study.

OBJECTIVE: To describe the association between knee and hip radiographic osteoarthritis (ROA), a measure of knee pain, stiffness and functional ability and objectively measured physiological falls risk predictors. METHODS: Cross-sectional, population-based study of 850 randomly selected men and women aged 50-80 years (mean 62.5, SD 7.4). Falls risk (Z score) was determined objectively with the short form Physiological Profile Assessment (PPA). Two observers assessed knee and hip ROA using the Altman atlas. Pain, stiffness and functional ability were assessed using the Western Ontario McMasters Osteoarthritis index (WOMAC). RESULTS: Overall, the study population was at a mild risk of falling. In multivariable analysis, the WOMAC function and pain score were significantly associated with reaction time, balance, proprioception, knee extension strength, and edge contrast sensitivity. Stiffness was associated with knee extension strength and edge contrast sensitivity. Males had a dose response association between the global WOMAC score and falls risk (r=0.17, P<0.001). Those who reported a global WOMAC score of 50 and above had a higher risk of falling compared to those with a score below 50 (Z score: 0.53 vs 0.14, P<0.001). Hip joint space narrowing (JSN) was significantly associated with knee extension strength (r=-0.10, P=0.003), however, no other significant associations were observed between ROA and falls risk predictors. CONCLUSION: Self-reported functional ability and pain, and to a lesser extent, stiffness (but not knee and hip ROA), have a modest but independent association with physiological predictors of falls risk.

Accidental Falls↗
PubMed2002

Baseline blood pressure but not early computed tomography changes predicts major hemorrhage after streptokinase in acute ischemic stroke.

BACKGROUND AND PURPOSE: Intracerebral hemorrhage is the most serious complication of thrombolytic therapy for stroke. We explored factors associated with this complication in the Australian Streptokinase Trial. METHODS: The initial CT scans (< or =4 hours after stroke) of 270 patients were reviewed retrospectively by an expert panel for early signs of ischemia and classified into the following 3 categories: no signs or < or =1/3 or >1/3 of the vascular territory. Hemorrhage on late CT scans was categorized as major or minor on the basis of location and mass effect. Stepwise, backward elimination, multivariate logistic regression analysis was used to identify risk factors for each hemorrhage category. RESULTS: Major hemorrhage occurred in 21% of streptokinase (SK) and 4% of placebo patients. Predictors of major hemorrhage were SK treatment (odds ratio [OR], 6.40; 95% CI, 2.50 to 16.36) and elevated systolic blood pressure before therapy (OR, 1.03; 95% CI, 1.01 to 1.05). Baseline systolic blood pressure >165 mm Hg in SK-treated patients resulted in a >25% risk of major secondary hemorrhage. Early ischemic CT changes, either < or =1/3 or >1/3, were not associated with major hemorrhage (OR, 1.58; 95% CI, 0.65 to 3.83; and OR, 1.11; 95% CI, 0.45 to 2.76, respectively). Minor hemorrhage occurred in 30% of the SK and 26% of the placebo group. Predictors of minor hemorrhage were male sex, severe stroke, early CT changes, and SK treatment. Ninety-one percent of patients with major hemorrhage deteriorated clinically compared with 23% with minor hemorrhage. CONCLUSIONS: SK increased the risk of both minor and major hemorrhage. Major hemorrhage was also more likely in patients with elevated baseline systolic blood pressure. However, early CT changes did not predict major hemorrhage. Results from this study highlight the importance of baseline systolic blood pressure as a potential cause of hemorrhage in patients undergoing thrombolysis.

Acute Disease↗
PubMed2000

Curved trajectory prediction using a self-organizing neural network.

Existing neural network models are capable of tracking linear trajectories of moving visual objects. This paper describes an additional neural mechanism, disfacilitation, that enhances the ability of a visual system to track curved trajectories. The added mechanism combines information about an object's trajectory with information about changes in the object's trajectory, to improve the estimates for the object's next probable location. Computational simulations are presented that show how the neural mechanism can learn to track the speed of objects and how the network operates to predict the trajectories of accelerating and decelerating objects.

Acceleration↗
PubMed1999

Effects of ethanol ingestion on sperm monosaccharides and fertility.

Chronic alcohol abuse is often associated with reproductive disorders. Sperm monosaccharides play an indispensable role in sperm-egg interactions and fertilization. Ethanol (3 g/kg body weight as 25%, v/v) was given by gastric intubation twice daily for 30 days while in another group, rats which had been treated with ethanol were withdrawn from treatment for a further period of 30 days, in order to assess the reversibility of the ethanol-induced effects. Epididymal ethanol content, sperm monosaccharides and the fertility of ethanol treated and ethanol withdrawn rats were assessed. Ethanol ingestion caused a significant decrease in sperm monosaccharides suggesting defective glycosylation of sperm surface proteins. Sperm monosaccharides and fertility were returned to normal following the withdrawal of ethanol. Ethanol-induced changes in sperm monosaccharides may be one of the reasons for the reduced fertility of ethanol treated rats.

Animals↗
PubMed1999

Effects of ethanol treatment on epididymal secretory products and sperm maturation in albino rats.

Alcoholics are often associated with fertility disturbances with low sperm count and impaired sperm motility. Spermatozoa attains forward motility and fertilizing capacity during their transit through the epididymis. Epididymal secretory products form a suitable microenvironment, which favors sperm maturation. To study the effects of ethanol on epididymal sperm maturation, ethanol (3 g/kg body weight as 25%, v/v) was given by gastric intubation twice daily for 30 days, and in another group, rats given treatment for 30 days were withdrawn of treatment for a further period of 30 days to assess the reversibility of ethanol-induced changes. Serum and epididymidal testosterone and dihydrotestosterone (DHT), epididymidal tissue and sperm carnitine, acetyl carnitine, glycerylphosphoryl choline (GPC), and sialic acid were studied along with epididymidal sperm count and cauda epididymidal sperm motility. Ethanol treatment significantly reduced the epididymal tissue/sperm carnitine, acetyl carnitine, GPC, and sialic acid, suggesting its adverse effect on these secretory products. Impaired cauda epididymidal sperm motility and fertility (in vivo) of ethanol-treated rats imply the defective sperm maturation. All these changes were reverted back to normalcy after withdrawal of ethanol treatment, indicating the transient effects of ethanol. In conclusion, it is evident that ethanol has an adverse effect on sperm maturation, which may be affected due to the decrease in serum/epididymal testosterone and DHT level and epididymal secretory products.

Acetylcarnitine↗
PubMed1998

Effects of ethanol ingestion on epididymal glycosidases and fertility in the rat.

Epididymal glycosidases play a role in sperm maturation by modifying sperm surface glycoproteins. To study the effects of ethanol on epididymal sperm maturation, ethanol (3 g/kg body weight as 25%, v/v) was administered to a group of rats by gastric-intubation twice daily for 30 days. In another group, rats were also treated with alcohol for 30 days but were then withdrawn from treatment for 30 days to assess the reversibility of ethanol-induced effects. Ethanol-induced changes in epididymal tissue and sperm glycosidases, cauda epididymal sperm motility and the fertility of rats were assessed. Ethanol treatment caused a marked decrease in the specific activities of glycosidases in both tissues and spermatozoa from epididymal segments. Cauda epididymal sperm motility and the fertility of ethanol-treated rats were significantly impaired compared to control rats fed an isocaloric diet. These changes are likely to be the consequence of direct and indirect effects of ethanol mediated through subnormal testosterone and dihydrotestosterone. Most of these changes were found to be reversible. The present study suggests that impaired activity of sperm glycosidases may be one of the factors responsible for defective sperm motility and fertilizing potential in ethanol-treated rats.

Animals↗
PubMed1998

Effects of ethanol ingestion on insulin binding to rat Leydig cells.

Effects of ethanol treatment and its withdrawal on insulin binding to isolated rat Leydig cells were studied. Mature rats were given ethanol by gastric intubation for 30 days at a dose of 3.0 g/kg body weight, twice daily, as a 25% (v/v) aqueous solution and treatment was withdrawn for the subsequent 30 days in an another group. Ethanol treatment markedly increased serum insulin and reduced the 125I-insulin binding to Leydig cells and the activities of Leydig cellular steroidogenic enzymes such as 3 beta-HSD and 17 beta-HSD. Withdrawal of ethanol treatment restored these changed values to their normal levels. The results suggest the possible involvement of subnormal insulin actions, as that of LH, in the ethanol-induced impairment of Leydig cellular steroidogenesis and the resulting hypoandrogenization associated with alcohol abuse.

Animals↗
PubMed1995

Effects of ethanol treatment on Leydig cellular NADPH-generating enzymes and lipid profiles.

Effects of ethanol treatment on Leydig cell NADPH-generating enzymes and lipid profiles were studied. Ethanol treatment (3.0 g/kg b.wt.) twice daily as a 25% (v/v) aqueous solution given to adult Wistar rats reduced the body weight, testis weight and relative weights of the seminal vesicles and ventral prostate. Serum LH and testosterone were also decreased. Similarly, the NADPH-generating enzymes such as G-6-PDH, 6-PGDH, NADP-ICDH were reduced, but malic enzyme was unaltered. Leydig cell total lipid was decreased: neutral lipids such as esterified cholesterol and triacyl glycerol were decreased but free cholesterol and diacyl glycerol were increased. The reduction in total phospholipid was contributed to by fractions such as phosphatidyl inositol, phosphatidyl serine, phosphatidyl choline and phosphatidyl ethanolamine. Withdrawal of ethanol treatment for 30 days restored these to the normal level. The present findings suggest that the ethanol treatment impairs Leydig cellular NADPH generation which may be one of the biochemical mechanisms mediating the direct and indirect effects of ethanol resulting in hypoandrogenization.

Animals↗
PubMed1993

Effect of chronic alcoholism on semen--studies on lipid profiles.

The effect of chronic alcoholism on various seminal parameters (sperm concentration, rate of forward motility, percentage of abnormal spermatozoa, lipid profiles of seminal plasma and spermatozoa) was studied together with the serum levels of testosterone and oestradiol. In chronic alcoholics there was a marked reduction in sperm concentration and in the rate of their forward motility, and increase in the number of spermatozoa with morphological abnormalities when compared to age-matched normal fertile subjects. Serum levels of testosterone were decreased while oestradiol levels were increased in chronic alcoholic men. Studies of lipid profiles showed a marked decrease in the total phospholipid concentration in spermatozoa, primarily in sphingomyelin, phosphatidyl choline and ethanolamine fractions. The cholesterol:phospholipid ratio in spermatozoa was increased in alcoholics. In the seminal plasma of chronic alcoholics, there was a decrease in total lipid, in glyceride glycerol and in free and esterified cholesterol. Of the phospholipid classes, sphingomyelin and phosphatidyl ethanolamine showed a significant reduction. In general, the present study provides evidence for the adverse effects of chronic alcoholism on serum hormones, sperm count, morphology, motility and seminal lipid profiles. These may be responsible for the fertility disorders common in chronic alcoholics.

Alcoholism↗
PubMed1993

Specific activities of seminal vesicular phosphomonoesterases and Mg2+-,Ca2+- and Na+/K(+)-adenosine triphosphatases in hypo- and hyperthyroid albino rats.

Hypothyroidism (surgical thyroidectomy) inhibited the activities of acid phosphatase and Mg(2+)-ATPase in seminal vesicular tissue and fluid and that of Ca(2+)- and Na+/K(+)-ATPases in fluid alone, and T4 supplementation restored normalcy in all, except acid phosphatase. Hyperthyroidism (T4 25 micrograms/100g body weight/day for 60 days, im) enhanced the activities of alkaline phosphatase and ATPases in seminal vesicular tissue and fluid, and decreased acid phosphatase activity in tissue alone. Withdrawal of T4 treatment from hyperthyroid rats (after 30 days) augmented the activity of ATPases in tissue and impaired the same in fluid, while phosphomonoesterases remained at hyperthyroid level. The results suggest specific responses of various seminal vesicular phosphatases to altered thyroid hormone status. Modification in the specific threshold of androgen/estrogen action on different phosphatases in seminal vesicles appears to be the plausible mechanism underlying these changes in hypo- and hyperthyroid conditions.

Adenosine Triphosphatases↗