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Biomedical subjects

H Singh

Publications and source records attributed to H Singh.

At least 37 records · Page 2Linked to original sources
PubMed2004

Quantitative hepatic phosphorus-31 magnetic resonance spectroscopy in compensated and decompensated cirrhosis.

Few studies have examined the physiological/biochemical status of hepatocytes in patients with compensated and decompensated cirrhosis in situ. Phosphorus-31 magnetic resonance spectroscopy ((31)P MRS) is a noninvasive technique that permits direct assessments of tissue bioenergetics and phospholipid metabolism. Quantitative (31)P MRS was employed to document differences in the hepatic metabolite concentrations among patients with compensated and decompensated cirrhosis as well as healthy controls. All MRS examinations were performed on a 1.5-T General Electric Signa whole body scanner. The concentration of hepatic phosphorylated metabolites among patients with compensated cirrhosis (n = 7) was similar to that among healthy controls (n = 8). However, patients with decompensated cirrhosis (n = 6) had significantly lower levels of hepatic ATP compared with patients with compensated cirrhosis and healthy controls (P < 0.02 and P < 0.009, respectively) and a higher phosphomonoester/phosphodiester ratio than controls (P < 0.003). The results of this study indicate that metabolic disturbances in hepatic energy and phospholipid metabolism exist in patients with decompensated cirrhosis that are not present in patients with compensated cirrhosis or healthy controls. These findings provide new insights into the pathophysiology of hepatic decompensation.

Adenosine Triphosphate↗
PubMed2004

Antifungal potential of Indian medicinal plants.

Fourteen Indian plants, selected based on their use in respiratory and other disorders in traditional systems of medicine, were analyzed for their potential activity against fungi. The antifungal activity was investigated by disc diffusion, microbroth dilution and percent spore germination inhibition tests against pathogenic Aspergilli. Methanolic extracts of Solanum xanthocarpum and Datura metel inhibited the growth of Aspergillus fumigatus, A. flavus and A. niger and their in vitro MICs were found to be 1.25-2.50 mg/ml by both microbroth dilution and percent spore germination assays. In disc diffusion assay, a concentration of 0.062 mg/disc of methanol extract of D. metel showed significant activity against Aspergilli. S. xanthocarpum exhibited similar activity at 0.125 mg/disc.

Antifungal Agents↗
PubMed2004

Heterosis studies for yield and its components in bread wheat over environments.

A set of diallel crosses involving 10 parents was made to have information on the extent of heterosis over mid-parent and better parent and inbreeding depression for yield and yield contributing characters under three different environments. Marked heterobeltiosis for grain yield and its important components were observed. For grain yield, 83 crosses showed significant positive heterobeltiosis in all the three sowing dates, however, twenty crosses showed significant consistent heterobeltiosis for grain yield per plant over all the three environments. The maximum heterobeltiosis for grain yield per plant observed was 50.94% (Raj 3765 x HD 2285), 121.08% (PBW 373 x HD 2329) and 93.96% (PBW 373 x HD 2329) under early, normal and late sowing conditions, respectively. Cross PBW 373 x HD 2329 in both early and normal plantings and cross Raj 3765 x HD 2285 under late planting were observed most heterotic for grain yield. The crosses showing heterosis for grain yield were not heterotic for all the characters. Heterosis for grain yield per spike followed by tillers per plant and 1000-grain weight was independently associated with heterosis for grain yield in early and normal plantings. However, heterosis for grain yield per spike, dwarf plant height and tillers per plant contributed maximum towards yield heterosis. Significant inbreeding depression was recorded frequently for yield and yield contributing traits, however, in a few traits it was observed significant negative indicated that F(2) was superior to F(1) considered desirable combination for trait(s). The study reveals good scope for commercial exploitation of heterosis as well as isolation of pure lines among the progenies of heterotic F(1) for improvement of yield levels in bread wheat.

Analysis of Variance↗
PubMed2004

High-pressure-induced interactions between milk fat globule membrane proteins and skim milk proteins in whole milk.

The association of beta-lactoglobulin (beta-LG) and alpha-lactalbumin (alpha-LA) with milk fat globule membrane (MFGM), when whole milk was treated by high pressure in the range 100 to 800 MPa, was investigated using sodium dodecyl sulfate (SDS)-PAGE under reducing and nonreducing conditions. In SDS-PAGE under reducing conditions, beta-LG was observed in the MFGM material isolated from milk treated at 100 to 800 MPa for 30 min, and small amounts of alpha-LA and kappa-casein were also observed at pressures >600 MPa for 30 min. However, these proteins were not observed in SDS-PAGE under nonreducing conditions. These results indicate that beta-LG and alpha-LA associated with MFGM proteins via disulfide bonds during the high-pressure treatment of whole milk. The amount of beta-LG associated with the MFGM increased with an increase in pressure up to 800 MPa and with increasing time of pressure treatment. The maximum value for beta-LG association with the MFGM was approximately 0.75 mg/g of fat. Of the major original MFGM proteins, no change in butyrophilin was observed during the high-pressure treatment of whole milk, whereas xanthine oxidase was reduced to some extent beyond 400 MPa. In contrast to the behavior during heat treatment, PAS 6 and PAS 7 were stable during high-pressure treatment, and they remained associated with the MFGM.

Animals↗
PubMed2004

A novel antifungal pyrrole derivative from Datura metel leaves.

Phytochemical investigation of the leaves of Datura metel Linn. led to the isolation of a new pyrrole derivative 1 which was characterised as 2beta-(3,4-dimethyl-2,5-dihydro-1H-pyrrol-2-yl)-1'-methylethyl pentanoate on the basis of spectral data analyses and chemical reactions. Compound 1 was endowed with antifungal activity and its MIC was found to be 87.5 microg/ml. Two proteins having molecular weights of 42 and 58 kD of Aspergillus fumigatus are potential targets for compound 1.

Antifungal Agents↗
PubMed2003

Monitoring of flocculation and creaming of sodium-caseinate-stabilized emulsions using diffusing-wave spectroscopy.

Diffusing-wave spectroscopy (DWS) has been used to study the stability of sodium-caseinate-stabilized emulsions. The emulsions underwent creaming as a result of depletion flocculation when excess sodium caseinate was added. The creaming process was monitored over a 3-h period and each autocorrelation function was collected for 2 min to ensure adequate signal-to-noise ratio. The temporal variation of average particle size times the coefficient of viscosity of the continuous phase was derived from the backscattering measurements, and the variation of the scattering mean free path length with time was found from the backscattering and transmission measurements. It was confirmed that the creaming process was delayed at high oil concentrations, presumably due to the formation of oil droplet networks.

Journal Article↗
PubMed2003

Mapping of a resistance gene effective against Karnal bunt pathogen of wheat.

A set of 130 wheat recombinant inbred lines (RILs) developed from a cross between parents susceptible (WL711) and resistant (HD29) to Karnal bunt (caused by Tilletia indica), were screened for 3 years with the pathogen populations prevalent in northern India. When 90 simple sequence repeats (SSRs) and 81 amplified fragment length polymorphism (AFLP) loci were mapped on the RILs, markers on chromosomes 2A, 4B and 7B accounted collectively for about one-third of the variation in the disease reaction. The genomic region of largest effect, identified on the long arm of chromosome 4B, reduced Karnal bunt disease by half in three different experiments and accounted for up to 25% of the phenotypic variation for KB reaction. A closely linked SSR marker, GWM538, may be useful in marker-assisted selection for Karnal bunt resistance in wheat.

Chromosome Mapping↗
PubMed2003

Distribution of Kir6.0 and SUR2 ATP-sensitive potassium channel subunits in isolated ventricular myocytes.

The subcellular distribution of ATP-sensitive potassium (K(ATP)) channel subunits in rat-isolated ventricular myocytes was investigated using a panel of subunit-specific antisera. Kir6.1 subunits were associated predominantly with myofibril structures and were co-localized with the mitochondrial marker MitoFluor red (correlation coefficient (cc) = 0.63 +/- 0.05). Anti-Kir6.1 antibodies specifically recognized a polypeptide of 48 kDa in mitochondrial membrane fractions consistent with the presence of Kir6.1 subunits in this organelle. Both Kir6.2 and SUR2A subunits were distributed universally over the sarcolemma. Lower-intensity antibody-associated immunofluorescence was detected intracellularly, which was correlated with the distribution of MitoFluor red in both cases (cc, Kir6.2, 0.56 +/- 0.05; SUR2A, 0.61 +/- 0.06). A polypeptide of 40 kDa was recognized by anti-Kir6.2-subunit antibodies in western blots of both microsomal and mitochondrial membrane fractions consistent with the presence of this subunit in the sarcolemma and mitochondria. Similarly, SUR2A and SUR2B subunits were detected in western blots of microsomal membrane proteins consistent with a sarcolemmal localization for these polypeptides. SUR2B subunits were shown in confocal microscopy to co-localize strongly with t-tubules (cc, 0.81 +/- 0.05). Together, the results indicate that Kir6.2 and SUR2A subunits predominate in the sarcolemma of ventricular myocytes consistent with a Kir6.2/SUR2A-subunit combination in the sarcolemmal K(ATP)channel. Kir6.1, Kir6.2 and SUR2A subunits were demonstrated in mitochondria. Combinations of these subunits would not explain the reported pharmacology of the mitochondrial K(ATP) channel (Mol Pharmacol 59 (2001) 225) suggesting the possibility of further unidentified components of this channel.

ATP-Binding Cassette Transporters↗
PubMed2003

A retrospective audit of long-term lower limb complications following leg vein harvesting for coronary artery bypass grafting.

OBJECTIVE: To evaluate the prevalence of leg complications following leg-vein harvest for coronary artery bypass grafting. METHOD: A questionnaire was sent to patients who had coronary artery bypass surgery between January 1993 and December 1998. Questions addressed pain, numbness, infection, swelling and general healing. The relationship between the risk factors of diabetes, peripheral vascular disease, previous fractures/injuries to legs, previous deep vein clots and arthritis affecting the legs with post operative symptoms of pain, numbness, swelling and general healing was explored with multivariate analysis. RESULTS: Of 700 questionnaires sent out 497 were returned, of which 422 (60%) were suitable for analysis. Numbness or tingling related to the wound was reported by 256 (61%), of whom 94 (37%) improved within 3 months. However, 105 (41%) had persistent numbness beyond 2 years. Pain in the wound was reported by 193 (46%), of whom 149 (77%) reported that this had improved by 3 months and only 19 (10%) had pain persisting beyond 2 years. A leg wound infection was reported by 126 (32%) patients, with 82 (65%) of these receiving antibiotics. A total of 336 (87% of 387 responses) described their wound as completely healed at 3 months. Unilateral leg swelling was reported by 175 (41%) with 98 of these (56% of those with swelling) improving by 3 months and 41 (23%) with swelling persisting beyond 2 years. There was no relation of wound problems to examined risk factors diabetes (P-values for numbness 0.31, wound healing 0.15, swelling 0.21, pain 0.22) and peripheral vascular disease (P-values for numbness 0.8, wound healing 0.21, swelling 0.18, pain 0.09). There was insufficient data to comment on the influence of fractures/injuries to legs, previous deep vein clots and arthritis affecting the legs. CONCLUSIONS: Wound complications are common following leg vein harvest. Prevalence of infection was higher than has previously been reported. Few people suffer long-term pain from saphenous nerve damage although paraesthesia and swelling were common long-term complications. We did not identify either diabetes or peripheral vascular disease as a risk factor for pain, numbness, swelling or problems with general healing. There is a need for a large multicentre prospective study.

Adult↗
PubMed2003

Platelet indices as quality markers of platelet concentrates during storage.

The quality of platelet concentrates (PC) is an important issue in transfusion therapy. Recently, platelet indices have been used as markers for the quality control of PCs, as these reflect storage-induced shape changes in platelets. We also analyzed platelet indices such as platelet count, which could be detrimental and influence the rate of pH change during acceptable storage conditions. In the present study, platelet indices (with and without EDTA) were analyzed in stored PC. Forty pooled PRP-PCs were stored for 7 days and various platelet indices were analyzed with and without EDTA incubation. These indices included platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW) and platelet large cell ratio (PLCR). Difference in platelet paramters dPLT, dMPV, dPDW and dPLCR were calculated. Platelet indices correlating with pH changes, as determined by regression analysis, included dMPV and dPDW, while dPLT did not show much correlation (P < 0.05). Mean pH decreased from 7.25 to 6.86 between day 0 and day 7, respectively (P > 0.05). Platelet indices correlating with pH included PDW and MPV, while PLT did not show much correlation with pH. The platelet index dPDW (r = -0.26) and dMPV (r = -0.18) showed maximum, but not perfect, correlation with pH (P < 0.01). The coefficient of determination (R2) was maximum for the platelet indices dPDW and dP-LCR (R2 > 0.6). We conclude that measurements of platelet indices after EDTA incubation have great potential as quality markers of PC, especially when analyzed in combination with pH.

Biomarkers↗
PubMed2003

High frequency of hepatitis B virus infection in patients with beta-thalassemia receiving multiple transfusions.

BACKGROUND AND OBJECTIVES: Hepatitis B virus (HBV) may occasionally be transmitted through transfusion of blood units that are hepatitis B surface antigen (HBsAg) negative but HBV DNA positive. Children with beta-thalassemia are particularly susceptible to HBV because they receive multiple blood transfusions. These children have high infection rates despite vaccination against HBV. Post-vaccination infections may be a result of viruses harbouring surface (S)-gene mutations (e.g. G587A) in a region critical for reactivity to antibody to hepatitis B surface antigen (anti-HBs). The true prevalence of HBV in individuals with beta-thalassemia has not been studied previously. PATIENTS AND METHODS: Seventy patients with beta-thalassemia (median age 6 years; range 8 months to 22 years; 49 male), who had received seven to 623 (median 61) units of blood each and three doses (10/20 micro g) of HBV vaccine (Engerix B) before presentation to us, were included in the study; 50 of the 70 patients had received transfusions prior to vaccination. Enzyme-linked immunoassay for serological markers [HBsAg, antibody to hepatitis B core antigen (anti-HBc) and quantitative anti-HBs] and polymerase chain reaction (PCR) followed by Southern hybridization for molecular detection of hepatitis B, was performed on all samples. The PCR-amplified product was cloned, sequenced and the nucleotide and deduced amino acid sequences for the HBV S and polymerase (P) genes were analysed for mutations. RESULTS: Four of 70 (5.7%) individuals with beta-thalassemia were HBsAg positive and 14 (20%) were anti-HBc positive. The prevalence of serological markers increased with number of transfusions (P < 0.01). Of 70 patients, 53 (75.7%) had an anti-HBs titre of > 10 IU/l following vaccination and 17 (24.3%) were non-responders (< 10 IU/l); 22 (31.4%) of the 70 were DNA positive. The frequency of HBV infection in beta-thalassemia was similar in vaccine responders and non-responders. The virus was of subtype ayw (genotype D) in the five DNA-positive samples in which a 388-nucleotide region of the S gene was sequenced. Mutations occurred at 13 positions in the S gene and at 10 positions in the P gene. Hydrophobicity plots revealed differences in amino acid regions 117-165 and 195-211. Some of these amino acid substitutions coincided with the putative cytotoxic T-lymphocyte epitopes of both S and P proteins. CONCLUSIONS: A high frequency of HBV infection was seen using molecular methods in thalassemic patients. The frequency of infection was similar in vaccine responders and non-responders. A number of mutations were observed in the S gene, which could have implications for viral replication as well as virus-host cell interaction.

Adolescent↗
PubMed2003

Artificial neural networks in predicting optimum renal stone fragmentation by extracorporeal shock wave lithotripsy: a preliminary study.

OBJECTIVE: To assess the ability of artificial neural networks (ANNs) to predict optimum renal stone fragmentation in patients being managed by extracorporeal shock wave lithotripsy (ESWL). PATIENTS AND METHODS: The study included 82 patients with renal stones who were being treated by ESWL. Data (input and output values) from 60 patients in whom there was optimum fragmentation of stones by ESWL were used for training the ANN. These data mainly included the 24-h urinary variables, the radiological features of the stone disease and the ESWL settings used. The predictability of the trained ANN was tested on 22 subsequent patients, by supplying the input variables of the 22 patients into the trained ANN and recording the output values (predicted values). After subjecting these patients to ESWL, the actual results (observed values) were recorded. The predicted and the observed values were then compared. RESULTS: In the 22 patients in whom predictability was tested, the trained ANN predicted optimum fragmentation at < or = 13 000 shocks/stone (as per study protocol) in 17 and optimum fragmentation at> 13 000 shocks/stone in the other five. In the 17 patients (test set) where the trained ANN had predicted optimum fragmentation at < or = 13 000 shocks/stone, the optimum fragmentation was at that value, although the predicted and observed values were not identical. The overall correlation between the predicted and the observed values was 75.5% (correlation coefficient 0.7547) in these 17 patients. Of the other five patients, none had optimum fragmentation at < 13 000 shocks/stone, as predicted by the trained ANN, giving complete accuracy for this factor. CONCLUSION: This was a pilot study, i.e. an initial attempt to use an ANN in this regard, and although there were few patients, such that it is not possible to make final recommendations, the overall predictability was approximately 75%. An encouraging outcome of the study was that the trained ANN identified patients unlikely to benefit from ESWL. Using a larger dataset and identifying more significant variables, while eliminating inputs with a negative effect, the efficiency and utility of this ANN can probably be enhanced and in future it might be possible to predict stone fragmentation with reasonable accuracy.

Humans↗
PubMed2003

Utility of intradermal smear in the diagnosis of malaria.

The objective of this preliminary study was to evaluate the usefulness of the intradermal smear test in the diagnosis of malaria. One hundred cases of suspected malaria (having received no prior antimalarials) were investigated. Both peripheral blood film (PBF) and intradermal smears (IDS) were simultaneously prepared and patients placed on antimalarial therapy. The slides were repeated for the next 2 days. At admission, 70 cases were positive on PBF--59 were Plasmodium falciparum (PF) and 11 were Plasmodium vivax (PV) whereas surprisingly 62 cases were positive on IDS at admission--61 were PF, one was PV. IDS identified two more cases of PF [P value (not significant)] but failed to identify any new cases of PV (P value NS). On subsequent days IDS positivity for PF was higher than for PBF (P < 0.05 for day 1 and P < 0.001 for day 2). However, the PV yield was poor for any further statistical evaluation on subsequent days. We conclude that IDS is simple, easy to perform, requires no special infrastructure compared to PBF, and is a helpful diagnostic tool in cases where malaria is strongly suspected but peripheral blood slides are repeatedly negative due to prior use of antimalarial therapy. IDS may be added to routine PBF in malaria (especially PF).

Adolescent↗
PubMed2003

Rheological properties of concentrated skim milk: importance of soluble minerals in the changes in viscosity during storage.

Properties of condensed milks prior to spray drying dictate to a large extent the functionality of the resulting milk powder. Rheological properties of concentrated skim milk, with total solids content of 45% but different mineral content, were studied as a function of shear rate and storage time at 50 degrees C. These milks are proposed as a model to study the effects of minerals on rheology and age gellation of condensed milk prior to drying. During storage of the concentrated milk, the apparent viscosity, particularly after 4 h, increased markedly at all shear rates studied. The yield stress also increased steeply after 4 h of storage at 50 degrees C. The changes in apparent viscosity of concentrated milk stored for up to 4 h were largely reversible under high shear, but irreversible in samples stored for longer time. The appearance of yield stress suggested the presence of reversible flocculation arising from weak attraction between casein micelles, with a transition from reversible to irreversible aggregation during storage. Particle size analysis confirmed irreversible aggregation and fusion of casein micelles during storage. Gradual reduction of mineral content of concentrated milks resulted in a marked decrease in the apparent viscosity and casein micelle aggregation during storage, while addition of minerals to milk had the opposite effect. The results demonstrated that the soluble mineral content is very important in controlling the storage-induced changes in the rheology of concentrated milks.

Animals↗
PubMed2003

Endoscopic third ventriculostomy in obstructed hydrocephalus.

Forty-three ETV were performed in 46 patients of obstructive hydrocephalus. Study was divided into two groups. Group 1 was with 29 children of less than two years age. Group 2 had seventeen patients of more than 2 years, adolescent and adults. Group 1 had 70% clinical and 63% radiological improvement whereas Group 2 showed 100% clinical and 73% radiological improvement. ETV failed in relieving the symptoms of hydrocephalus in eight patients. They were eventually benefited with VP Shunt. There was one postoperative death, which was not related to the procedure. ETV is an important alternative to VP Shunt in relieving hydrocephalus due to obstruction in CSF pathway.

Adolescent↗
PubMed2003

Clinical profile in gelatinous bone marrow transformation.

OBJECTIVE: To study the clinical spectrum associated with gelatinous bone marrow transformation (GMT). METHODS: All subjects whose bone marrow aspiration showed pink purple material on Leishman stain underwent a detail history, clinical examination and investigation (biochemical/microbiological/radiological). Additionally, in each subject the smear was stained with special stains of Periodic Acid Schiff and Alcian blue. RESULTS: Out of total 1498 marrows, 65 showed evidence of GMT. All of these had anaemia. The associated clinical spectra of diseases noticed were: Infection (31 cases), Nutritional deficiency (5 cases), Haematological disorders (Aplastic/toxic depression) (17 cases), Malignancies (3 cases), and Miscellaneous (9 cases). CONCLUSION: Based on the heterogenecity of associated clinical disorders, GMT indicates severe illness and not a particular disease. GMT may be a result of bioregulatory process (which presently needs further prospective studies) that are activated in different pathologic conditions but resulting in similar lesion in the bone marrow and so till then it may be concluded that GMT is a symptom of bone marrow.

Adolescent↗