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Biomedical subjects

S Kaushik

Publications and source records attributed to S Kaushik.

At least 19 recordsLinked to original sources
PubMed2006

Lower energy levels adequate for effective transcleral diode laser cyclophotocoagulation in Asian eyes with refractory glaucoma.

PURPOSE: To study the treatment parameters for diode laser cyclophotocoagulation (DLCP) in Asian Indian eyes using laser energy titrated to clinical response. METHODS: This prospective interventional longitudinal study included 66 eyes of 66 patients with varied aetiology refractory glaucoma, no previous cycloablation, and minimum 1 year follow-up. DLCP was performed using the Oculight Diode laser system IRIS( Medical Instruments Inc., CA, USA). Power used per spot was titrated according to the audible 'pops' indicating tissue microexplosion. The mean laser energy delivered, post-laser intraocular pressure (IOP) reduction, complications, and requirement of re-treatment in various subgroups were analyzed. Differences in energy delivered in each subgroup were assessed by analysis of variance with post hocBonferroni corrections. Linear regression analysis was used to identify possible predictive factors for failure of cyclodiode therapy. RESULTS: The mean total energy delivered per eye was 87.80+/-31.8 J (range 105.4+/-36.8 J in neovascular glaucoma (NVG) to 61.5+/-8.8 J in uveitic glaucoma (P=0.134)). Mean pre treatment IOP was 36.4+/-10.7 mmHg, which reduced to 19.4+/-9.8 mmHg (P<0.001) at 1 week, and 15.6+/-6.6 mmHg at 1 year. At 1 year, 58 of 66 patients had IOP<22.0 mmHg (response rate 87.8%), and six patients had hypotony (success rate 78.8%). The uveitic glaucoma group had 100% success rate. NVG group required maximum re-treatments. CONCLUSIONS: DLCP with a titrated energy protocol needs resulted in lower energy in Asian Indian eyes compared to that reported in literature, and different energy levels are needed for different diseases. 'Standard treatment parameters' for DLCP may be inappropriate for all diseases and all races.

Adolescent↗
PubMed2006

Autophagy as a cell-repair mechanism: activation of chaperone-mediated autophagy during oxidative stress.

Proper removal of oxidized proteins is an important determinant of success when evaluating the ability of cells to handle oxidative stress. The ubiquitin/proteasome system has been considered the main responsible mechanism for the removal of oxidized proteins, as it can discriminate between normal and altered proteins, and selectively target the latter ones for degradation. A possible role for lysosomes, the other major intracellular proteolytic system, in the removal of oxidized proteins has been often refused, mostly on the basis of the lack of selectivity of this system. Although most of the degradation of intracellular components in lysosomes (autophagy) takes place through "in bulk" sequestration of complete cytosolic regions, selective targeting of proteins to lysosomes for their degradation is also possible via what is known as chaperone-mediated autophagy (CMA). In this work, we review recent evidence supporting the participation of CMA in the clearance of oxidized proteins in the forefront of the cellular response to oxidative stress. The consequences of an impairment in CMA activity, observed during aging and in some age-related disorders, are also discussed.

Animals↗
PubMed2006

Rapid metabolic adaptation in European sea bass (Dicentrarchus labrax) juveniles fed different carbohydrate sources after heat shock stress.

A study was conducted to evaluate the effect of two dietary carbohydrate sources (waxy maize starch and glucose) on the metabolic adaptation of sea bass juveniles (initial weight: 24 g) to a heat shock treatment (temperature rise from 18 degrees C to 25 degrees C within 24 h). Two isonitrogenous and isolipidic diets were formulated to contain 20% waxy maize starch (WS diet) or 20% glucose (GLU diet). Triplicate groups of fish were fed to near satiation for 4 weeks at both temperatures (18 degrees C and 25 degrees C). Then, fish previously maintained at 18 degrees C were submitted to a heat shock (18 degrees C to 25 degrees C) and continued to be fed with the same diets during 1 more week. The higher water temperature significantly improved growth performance, feed efficiency, as well as protein efficiency ratio, independently of diet. At 25 degrees C, but not at 18 degrees C, growth of fish fed the WS diet was higher than that of fish fed the GLU diet. Plasma glucose levels were higher in sea bass fed the GLU diet and not influenced by water temperature. Fish fed a glucose diet or reared at high temperatures (25 degrees C) showed enhanced liver glycolytic, lipogenic and gluconeogenic capacities compared to fish fed a starch diet or reared at low temperatures (18 degrees C). For the majority of the enzymes studied, 1 week seemed to be enough time for metabolic adaptation in sea bass submitted to an acute heat shock. Irrespective of carbohydrate source, HSP70 gene expression was similar in both cold water (18 degrees C) and warm water (25 degrees C) acclimated sea bass. A weak down regulation was observed after heat shock only in fish fed the GLU diet. This suggests that HSP70 gene expression is not affected by the rearing temperature per se.

Adaptation, Physiological↗
PubMed2006

Ultrasound biomicroscopic quantification of the change in anterior chamber angle following laser peripheral iridotomy in early chronic primary angle closure glaucoma.

AIMS: To prospectively evaluate by ultrasound biomicroscopy (UBM) and gonioscopy the anterior chamber angle widening following laser peripheral iridotomy (LPI) in eyes with early chronic primary angle closure glaucoma (CACG). METHODS: A total of 55 eyes of 55 patients with CACG presenting with less than 180 degrees peripheral anterior synechiae (PAS) were enrolled in the study. Angles were assessed by gonioscopy (Shaffer's grading) and UBM, before and 4 weeks after LPI. The angle opening distance at 250 and 500 microm from the scleral spur (AOD 250 and AOD 500) was computed. Results were analysed using the Wilcoxon signed-rank test. RESULTS: In the quadrant with LPI, the mean gonioscopy grade increased significantly from 0.45 to 1.45 (P<0.001) and the mean AOD 250 and AOD 500 increased from 38.5+/-25.9 to 83.5+/-48.4 microm (P<0.001) and 110.2+/-80.9 to 170.6+/-83.4 microm (P<0.001), respectively. The angles widened significantly in the opposite quadrant on UBM (AOD 250: 48.8+/-31.5-82.7+/-43.9 microm, P<0.001; AOD 500:117.2+/-65.5-172.2+/-81.7 microm; P<0.001), but the median gonioscopy grade remained unchanged. CONCLUSIONS: LPI significantly widened the anterior chamber angle in the quadrant with LPI and the quadrant furthest away in patients of CACG with established glaucomatous damage. This change was much better appreciated by the UBM than gonioscopy.

Adult↗
PubMed2006

Computed tomography and magnetic resonance imaging of unusual causes of ankle pain.

Computed tomography and MRI are frequently utilized to evaluate ankle pain that remains unexplained by radiography. The most common causes of ankle pain are related to trauma and the imaging appearances of these entities are well established in the radiologic and orthopedic literature. A smaller percentage is comprised of non-traumatic disorders. Our goal is to emphasize the value of CT and MRI in recognition of these less common and unusual causes of ankle pain.

Ankle Injuries↗
PubMed2005

Effect of normal and waxy maize starch on growth, food utilization and hepatic glucose metabolism in European sea bass (Dicentrarchus labrax) juveniles.

We determined the effect of dietary starch on growth performance and feed utilization in European sea bass juveniles. Data on the dietary regulation of key hepatic enzymes of the glycolytic, gluconeogenic, lipogenic and amino acid metabolic pathways (hexokinase, HK; glucokinase, GK; pyruvate kinase, PK; fructose-1,6-bisphosphatase, FBPase; glucose-6-phosphatase, G6Pase; glucose-6-phosphate dehydrogenase, G6PD; alanine aminotransferase, ALAT; aspartate aminotransferase, ASAT and glutamate dehydrogenase, GDH) were also measured. Five isonitrogenous (48% crude protein) and isolipidic (14% crude lipids) diets were formulated to contain 10% normal starch (diet NS10), 10% waxy starch (diet WS10), 20% normal starch (diet NS20), 20% waxy starch (diet WS20) or no starch (control diet). Another diet was formulated with no carbohydrate, and contained 68% crude protein and 14% crude lipids (diet HP). Each experimental diet was fed to triplicate groups of 30 fish (initial weight: 23.3 g) on an equivalent feeding scheme for 12 weeks. The best growth performance and feed efficiency were achieved with fish fed the HP diet. Neither the level nor the nature of starch had measurable effects on growth performance of sea bass juveniles. Digestibility of starch was higher with waxy starch and decreased with increasing levels of starch in the diet. Whole-body composition and plasma metabolites, mainly glycemia, were not affected by the level and nature of the dietary starch. Data on enzyme activities suggest that dietary carbohydrates significantly improve protein utilization associated with increased glycolytic enzyme activities (GK and PK), as well as decreased gluconeogenic (FBPase) and amino acid catabolic (GDH) enzyme activities. The nature of dietary carbohydrates tested had little influence on performance criteria.

Animals↗
PubMed2005

Rainbow trout can discriminate between feeds with different oil sources.

The purpose of present two-choice trials was to examine the capacity of groups of juvenile rainbow trout to differentiate between two isolipidic diets containing distinct oils and to detect an eventual preference. The choice was offered by means of two self-feeders per tank. One feeder distributed a standard diet with fish oil (FO), the other a diet containing vegetable oil, either rich in linolenic acid (linseed oil, LO), linoleic acid (sunflower oil, SO), or oleic acid (rapeseed oil, RO). Each 15-day preference test was preceded by a 15-day adaptation period during which both feeders distributed the same diet. The tests were followed by a 10- to 15-day validation period in order to confirm that feeder solicitations were steered by the characteristics of the diets. Preferences were expressed as relative changes in feed demands for a specific feeder. Averaged over all groups, the preference tests demonstrated the capacity of rainbow trout to discriminate between a diet with FO and a diet containing vegetable oil, and indicated a general preference for the diet with FO over the other diets irrespective of whether they received the diet with fish oil (Experiment 1) or with vegetable oil (Experiment 2) prior to the preference test. The tests also indicated a difference in the extent of relative avoidance of each of the three vegetable oil diets. Diet LO was the most avoided, as indicated by the 37-39% decrease in demands for the feeder with diet LO (P<0.05). Diet RO was the best accepted, causing a decrease in feed demands of only 15-17% (P>0.05). The avoidance of diet SO at the end of the preference test was 30% (P>0.05) after an initially higher avoidance of 43% (P<0.05). It is believed that the metabolic consequences of the excess of linolenic or linoleic acid negatively affected the feed acceptances of diets LO and SO. Further work is needed to elucidate a possible interference of differences in palatability. In all groups, the lower demands for the vegetable oil diets were compensated by increased demands for diet FO. Hence, changes in diet selection had no effect on total feed or energy intakes, measured as the sum of both selections.

Analysis of Variance↗
PubMed2005

Nutritional and hormonal control of lipolysis in isolated gilthead seabream (Sparus aurata) adipocytes.

We examined the effects of diet composition and fasting on lipolysis of freshly isolated adipocytes from gilthead seabream (Sparus aurata). We also analyzed the effects of insulin, glucagon, and growth hormone (GH) in adipocytes isolated from fish fed with different diets. Basal lipolysis, measured as glycerol release, increased proportionally with cell concentration and time of incubation, which validates the suitability of these cell preparations for the study of hormonal regulation of this metabolic process. Gilthead seabream were fed two different diets, FM (100% of fish meal) and PP (100% of plant protein supplied by plant sources) for 6 wk. After this period, each diet group was divided into two groups: fed and fasted (for 11 days). Lipolysis was significantly higher in adipocytes from PP-fed fish than in adipocytes from FM-fed fish. Fasting provoked a significant increase in the lipolytic rate, about threefold in isolated adipocytes regardless of nutritional history. Hormone effects were similar in the different groups: glucagon increased the lipolytic rate, whereas insulin had almost no effect. GH was clearly lipolytic, although the relative increase in glycerol over control was lower in isolated adipocytes from fasted fish compared with fed fish. Together, we demonstrate for the first time that lipolysis, measured in isolated seabream adipocytes, is affected by the nutritional state of the fish. Furthermore, our data suggest that glucagon and especially GH play a major role in the control of adipocyte lipolysis.

Adipocytes↗
PubMed2005

Effects of low protein intake on extra-hepatic gluconeogenic enzyme expression and peripheral glucose phosphorylation in rainbow trout (Oncorhynchus mykiss).

The objective of the study described here was to analyze in rainbow trout (Oncorhynchus mykiss) the effects of low protein intake on peripheral glucose phosphorylation capacities and gluconeogenic enzymes in kidney and intestine. Fish were food-deprived for 14 days or kept under a low and a high protein intake regime using a pair feeding protocol in order to maintain constant carbohydrate and lipid intakes. We analyzed the effect of protein restriction on (i) hepatic, renal and intestinal fructose-1.6-bisphophatase (FBPase) and glucose-6-phosphatase (G6Pase) enzymes at the molecular and enzymatic levels and (ii) glucose phosphorylation activities (hexokinases) in the liver, peri-visceral adipose tissue, red muscle and white muscle. Irrespective of the nutritional status, we observed the same levels of hexokinase activities in all the tissues studied. Renal G6Pase and FBPase gene expression and activities were not modified among the groups. In contrast, there was increased intestinal FBPase gene expression in fish under a low protein intake and higher G6Pase activities in both groups of fed fish. This result differs from what is observed in rats and suggest a role of intestine in the regulation of postprandial gluconeogenesis in fed trout. In conclusion, our data did not demonstrate any specific effect of low dietary protein intake to either gluconeogenic capacities or glucose phosphorylation capacities in rainbow trout.

Animals↗
PubMed2005

CDC staging based on absolute CD4 count and CD4 percentage in an HIV-1-infected Indian population: treatment implications.

CD4+ T-cell levels are an important criterion for categorizing HIV-related clinical conditions according to the CDC classification system and are therefore important in the management of HIV by initiating antiretroviral therapy and prophylaxis for opportunistic infections due to HIV among HIV-infected individuals. However, it has been observed that the CD4 counts are affected by the geographical location, race, ethnic origin, age, gender and changes in total and differential leucocyte counts. In the light of this knowledge, we classified 600 HIV seropositive antiretroviral treatment (ART)-naïve Indian individuals belonging to different CDC groups A, B and C on the basis of CDC criteria of both CD4% and CD4 counts and receiver operating characteristic (ROC) curves were generated. Importantly, CDC staging on the basis of CD4% indicated significant clinical implications, requiring an early implementation of effective antiretroviral treatment regimen in HIV-infected individuals deprived of treatment when classified on the basis of CD4 counts.

Adult↗
PubMed2005

Characterization of HIV-1 Gag-specific T cell responses in chronically infected Indian population.

India is at the epicentre of the global HIV/AIDS epidemic in South-east Asia, predominated by subtype C infections. It is important to characterize HIV-1-specific T cell responses in this particular population with the aim of identifying protective correlates of immunity to control HIV-1 infection. In this study, we performed a comprehensive analysis of the breadth and magnitude of T cell responses directed at HIV-1 subtype C Gag, one of the most conserved HIV-1 proteins. The study population consisted of antiretroviral naive, chronic HIV-1 subtype C-infected individuals at various stages of infection. We used recent advanced techniques such as enzyme-linked immunospot (ELISPOT) assay and intracellular cytokine staining to quantify the total CD4(+) and CD8(+) T cell response to HIV-1 gag at single peptide level, regardless of HLA haplotype of the infected individual. The p24-Gag was identified as the most frequently recognized subunit protein with the greatest magnitude of CD4(+) and CD8(+) T cell responses. Stronger and broader CD8 T cell responses were recognized, contrasting with the weaker and narrower CD4 T cell responses with regard to Gag protein subunits. The magnitude of the HIV-specific interferon (IFN)-gamma responses was observed to be higher than the corresponding interleukin (IL)-2 response, indicating the persistence of antigenic load in chronically infected Indian population due to the probable dysfunction of HIV-specific, IFN-gamma-secreting CD8 T cells in absence of IL-2 help.

Adult↗
PubMed2003

Proteomic sensitivity to dietary manipulations in rainbow trout.

Changes in dietary protein sources due to substitution of fish meal by other protein sources can have metabolic consequences in farmed fish. A proteomics approach was used to study the protein profiles of livers of rainbow trout that have been fed two diets containing different proportions of plant ingredients. Both diets control (C) and soy (S) contained fish meal and plant ingredients and synthetic amino acids, but diet S had a greater proportion of soybean meal. A feeding trial was performed for 12 weeks at the end of which, growth and protein metabolism parameters were measured. Protein growth rates were not different in fish fed different diets; however, protein consumption and protein synthesis rates were higher in the fish fed the diet S. Fish fed diet S had lower efficiency of retention of synthesised protein. Ammonia excretion was increased as well as the activities of hepatic glutamate dehydrogenase and aspartate amino transferase (ASAT). No differences were found in free amino acid pools in either liver or muscle between diets. Protein extraction followed by high-resolution two-dimensional electrophoresis, coupled with gel image analysis, allowed identification and expression of hundreds of protein. Individual proteins of interest were then subjected to further analysis leading to protein identification by trypsin digest fingerprinting. During this study, approximately 800 liver proteins were analysed for expression pattern, of which 33 were found to be differentially expressed between diets C and S. Seventeen proteins were positively identified after database searching. Proteins were identified from diverse metabolic pathways, demonstrating the complex nature of gene expression responses to dietary manipulation revealed by proteomic characterisation.

Amino Acids↗
PubMed2003

Effect of partial substitution of dietary protein by a single gluconeogenic dispensable amino acid on hepatic glucose metabolism in rainbow trout (Oncorhynchus mykiss).

Our objective was to understand the influence of dietary gluconeogenic amino acids on hepatic glucose metabolism in rainbow trout (Oncorhynchus mykiss). We analyzed the effects of partial substitution of dietary protein by a single gluconeogenic dispensable amino acid (DAA: alanine, aspartic acid or glutamic acid), on the regulation of hepatic glycolytic and gluconeogenic enzymes. We fed juvenile rainbow trout with isonitrogenous and isoenergetic diets in which part of nitrogen from fishmeal was replaced by nitrogen from one of the three DAA. Fish were fed over 9 weeks and samples withdrawn 6 h after feeding or 5 days after food deprivation. Our data did not show a clear effect of an excess of DAA on activities of glycolytic enzymes (glucokinase and pyruvate kinase) compared to the control diet. In contrast, feeding caused a significant repression of gluconeogenic enzyme activities (glucose-6-phosphatase, fructose-1,6-bisphosphatase and mitochondrial phosphoenolpyruvate carboxykinase) only in fish fed the three DAA substituted diets. However, these differences were insufficient to affect postprandial glycemia significantly. In conclusion, an excess of dietary DAA tested does not seem to modify glycemia or to have a negative impact on dietary carbohydrate utilization in rainbow trout.

Alanine↗
PubMed2003

Cloning and nutritional regulation of a Delta6-desaturase-like enzyme in the marine teleost gilthead seabream (Sparus aurata).

Marine fish are presumed to have a lower capacity than freshwater fish for the bioconvertion of 18C fatty acids into 20-22C highly unsaturated fatty acids (HUFA). The present work investigated the first step of this pathway, the Delta6-desaturation, in gilthead seabream. A full-length desaturase-like cDNA was identified from total RNA extracted from viscera of juvenile fish fed for 96 days on an experimental HUFA-free diet containing olive oil as the sole lipid source. The open reading frame encodes a 445-amino acid peptide that contains two membrane-spanning domains, three histidine-rich regions, and a cytochrome b(5) domain, which are characteristic of Delta6- and Delta5-desaturases. Predicted protein sequence of seabream desaturase-like indicated a high percentage of identity with mammalian Delta6-desaturases (approx. 65%). Northern analysis showed two transcripts of approximately 3.7 and 1.8 kb which were highly expressed in fish fed on HUFA-free diet and slightly expressed in fish fed on HUFA-rich diet. The fatty acid profile of the former group was characterized by high levels of Delta6-desaturation products (18:2 n-9 and 20:2 n-9) with no detectable levels of Delta5-desaturation product (20:3n-9). These results demonstrate for the first time the presence and nutritional modulation of a Delta6-desaturase-like cDNA in a marine fish.

Amino Acid Sequence↗
PubMed2003

Role of in vivo proton MR spectroscopy in the evaluation of adult brain lesions: our preliminary experience.

CONTEXT: A definite diagnosis and characterization of intracranial mass lesions, based on structural Magnetic Resonance Imaging (MRI) alone may be difficult. In such cases Proton Magnetic Resonance Spectroscopy (1H-MRS) along with other non-invasive techniques represents an advance in the specificity of brain lesion diagnosis. AIMS: The primary aim of this study was to evaluate the extent of the utility of 1H-MRS in adult brain tumors and their differentiation from similar-appearing space-occupying lesions. MATERIAL AND METHODS: MRS studies were performed on 1.5 Tesla whole body MR system using standard imaging head coil. Sixty patients (aged 30-65 years), including 35 males (31-65 years) and 25 females (30-65 years) were studied, along with 25 age-matched healthy volunteers (30-64 years). The Student 't' test was used to statistically analyze the spectroscopic data for significant difference in the metabolite ratios of the lesions from normal brain tissue. RESULTS: The Cho/Cr ratio was significantly raised in low and high-grade glioma and meningioma patients (1.85 +/- 0.36, 3.50 +/- 1.00 and 6.65 +/- 2.83 respectively) (mean +/- standard deviation), as compared with the control group (1.16 +/- 0.18); and NAA/Cr and NAA/Cho ratios were found to be lower than normal values in our study (P<0.01). However, in the non-neoplastic lesions, the Cho/Cr ratios were not statistically significant. The tubercular lesions revealed an average Cho/Cr ratio of 1.24 +/- 0.18, while it was 1.14 +/- 0.07 for infarcts. CONCLUSION: MR Spectroscopy was useful to arrive at a more definitive diagnosis in doubtful intracranial space-occupying lesions with similar morphological imaging patterns.

Adult↗
PubMed2002

Gluconeogenic enzyme gene expression is decreased by dietary carbohydrates in common carp (Cyprinus carpio) and gilthead seabream (Sparus aurata).

Our objective is to understand the low metabolic utilization of dietary carbohydrates in fish. We compared the regulation of gluconeogenic enzymes at a molecular level in two fish species, the common carp (Cyprinus carpio) and gilthead seabream (Sparus aurata), known to be relatively tolerant to dietary carbohydrates. After cloning of partial cDNA sequences for three key gluconeogenic enzymes (glucose-6-phosphatase (G6Pase), fructose biphosphatase (FBPase) and phosphoenolpyruvate carboxykinase (PEPCK) in the two species, we analyzed gene expressions of these enzymes 6 and 24 h after feeding with (20%) or without carbohydrates. Our data show that there is at least one gluconeogenic enzyme strongly regulated (decreased expression after feeding) in the two fish species, i.e. the PEPCK for common carp and G6Pase/FBPase for gilthead seabream. In these fish species, the regulation seems to be similar to the mammals at least at the molecular level.

Amino Acid Sequence↗
PubMed2002

Atypical manifestation of dural arteriovenous fistula.

A case of secondary dural arteriovenous fistula presenting as infantile stroke, in a fifteen month old boy, is reported. The initial impression on CT scan in this case was misleading, due to the atypical appearance of the pathological periventricular blood vessels, interpreted as periventricular calcification.

Central Nervous System Vascular Malformations↗