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Biomedical subjects

K K Gupta

Publications and source records attributed to K K Gupta.

At least 19 recordsLinked to original sources
PubMed2005

Regenerative mode locking via superposition of higher-order cavity modes in composite cavity fiber lasers.

We demonstrate a new method of optical pulse generation in regeneratively mode-locked fiber ring lasers (RML-FRLs). The method is based on generating dominant longitudinal modes in the fiber ring cavity by means of a composite cavity structure and their intermode beating at the photodetector incorporated in the regenerative feedback loop. The beat signal is then used as a modulation signal to generate optical pulses in a regenerative mode-locking scheme, thereby eliminating the requirement for a high-Q rf bandpass filter in a conventional RML-FRL. Optical pulses with a repetition frequency of 3.6 GHz have been generated successfully with a supermode noise suppression of more than 48 dB and a low phase noise of -85 dBc/Hz at 10 kHz offset from the carrier frequency.

Journal Article↗
PubMed2005

Variability pattern and correlation studies in Silybum marianum Gaertn.

Phenotypic and genotypic coefficient of variability, heritability in broad sense and genetic advance were determined investigating the characters of 15 accessions of Silybum marianum. Seed yield/plant and number of capsules/plant had highest estimates of genotypic variation, heritability and genetic advance which suggest that direct selection for these traits is suitable for the improvement of this crop. Number of capsules/plant had a significant positive correlation with the number of branches/plant and leaf length (r=0.3398, 0.7547), whereas seed yield/plant had a positive significant correlation with leaf length, stem diameter, capsule diameter and silymarin content (r=0.6830, 0.3140, 0.3484, 0.2925).

Genetic Variation↗
PubMed2005

Metal contents in the groundwater of Sahebgunj district, Jharkhand, India, with special reference to arsenic.

A detailed study has been presented on groundwater metal contents of Sahebgunj district in the state of Jharkhand, India with special reference to arsenic. Both tubewell and well waters have been studied separately with greater emphasis on tubewell waters. Groundwaters of all the nine blocks of Sahebgunj district have been surveyed for iron, manganese, calcium, magnesium, copper and zinc in addition to arsenic. Normal distribution statistic, exploratory data analysis and robust Z-score analysis have been employed to find out the distribution pattern, localisation of data, outliers and other related information. Groundwaters of three blocks of Sahebgunj, namely, Sahebgunj, Rajmahal and Udhawa have been found to be alarmingly contaminated with arsenic present at or above 10 ppb. Arsenic distribution patterns in these blocks are highly asymmetric in nature with the common feature of increasing width from first to fourth quartile. A very broad fourth quartile in each case represents a long asymmetric tail on the right of the median. Tubewell waters of at least two more blocks require regular monitoring to identify the outbreak of arsenic at the onset. Groundwaters of Sahebgunj district in general contain high iron and manganese. It is by and large soft in nature. Well waters have been found to be better with regard to arsenic but iron and manganese contents do not vary significantly. Normal distribution analysis (NDA), box and whisker (BW) plot and Z-score analysis together can provide a reasonably complete statistical picture of metal contents in Sahebgunj district groundwaters.

Arsenic↗
PubMed2005

Assessment of hypertension control in chronic kidney disease patients by ambulatory blood pressure monitoring.

BACKGROUND: Inadequate control of blood pressure (BP) increases cardiovascular mortality and morbidity in chronic kidney disease (CKD) and renal transplant patients. 24 hour ambulatory BP was recorded to evaluate the adequacy of BP control in these patients. METHODS: 60 CKD patients (25 conservative therapy, 16 maintenance hemodialysis, 19 renal transplant patients) were studied prospectively. After achieving clinic BP control, 24 hour ambulatory BP was recorded at 1 and 6 months. The patients were followed up for one year. RESULTS: Mean daytime and nighttime systolic blood pressure (SBP) both at 1 month and at 6 month was higher in non-survivors than in survivors. The survivors had better control of their daytime (p=0.018) as well as nighttime SBP levels (p=0.018) at 6 months compared to those at 1 month. Survivors achieved nocturnal dipping of SBP at 1 and 6 months (p=0.047, p=0.025, respectively). Non-survivors failed to achieve lower daytime (p=0.375) or nighttime SBP (p=0.254) at 6 months as compared to SBP at 1 month in spite of optimizing antihypertensive therapy. Daytime (p=0.022) and nighttime (p=0.029) diastolic BP (DBP) in the non-survivors was higher than in survivors. Nocturnal dip in DBP was not seen in either survivors at 1 (p=0.177) and 6 months (p=0.434) or non-survivors at 1 (p=0.408) and at 6 months (p=0.081). Renal transplant patients did not exhibit nocturnal dipping of BP. CONCLUSION: We conclude that, unlike survivors, there was worsening of 24 hour BP control in non-survivors. ABPM has a role in better management of total BP burden in CKD patients.

Adult↗
PubMed2004

Evaluation and standardisation of a simple HG-AAS method for rapid speciation of As(III) and As(V) in some contaminated groundwater samples of West Bengal, India.

A simple HG-AAS technique has been evaluated and standardised for rapid speciation of As(III) and As(V) in a number of contaminated groundwater samples of West Bengal, India. Citric acid has been used for selective hydride formation of As(III). The sensitivity of the evaluated HG-AAS method is 7.91 mg(-1)l, standard deviation, 0.001 and detection limit, 0.4 microg l(-1). As(III) sensitivity remains constant in the sample pH range of 2.3-10.6. Concomitant mineral matrix of the water samples did not interfere with arsenic determination. Eight out of ten groundwater samples analysed for As(IlI)and As(V) contain more As(III), which lies in the range of 54-350 ppb. As(III) estimation in drinking water along with total arsenic should be invoked as a policy for a realistic risk assessment of the contaminated water.

Arsenic↗
PubMed2000

Prevalence of human immunodeficiency virus infection in and around Varanasi, Uttar Pradesh, India.

Human Immunodeficiency Virus (HIV) infection is rising rapidly in the eastern Uttar Pradesh; however no data is available regarding its positivity rate. We have screened 1239 cases of various groups. HIV seropositivity rate of 0.28% was noted. These results suggest that HIV infection is spreading rapidly in this part of the country. M. tuberculosis was the commonest co-infection amongst them (29.5%). We recommend routine HIV screening of all patients of tuberculosis, especially if the persons frequent the cities, visit foreign countries where sex tourism is encouraged or stay away from their spouses for long periods as true history of sexual contact with commercial sex workers was difficult to obtain from them.

Adult↗
PubMed2000

Spontaneous intraperitoneal expulsion of an unruptured hydatid cyst.

We report a 43-year-old man with a 20 x 20 cm hydatid cyst, spontaneously extruded out from the left lobe of the liver. This complication of hydatid cyst has not been recorded earlier, and makes the case unique in itself and worth reporting. The patient presented with a rare complication of biliary peritonitis of hydatid disease.

Abdominal Pain↗
PubMed1995

Status of Ca(2+)-channels in hearts perfused with Ca(2+)-free medium as well as upon reperfusion (Ca(2+)-paradox).

Although a wide variety of biochemical changes have been observed during the occurrence of Ca(2+)-paradox, very little is known about membrane alterations during Ca(2+)-free perfusion which may predispose the heart to the development of intracellular Ca(2+)-overload in the Ca(2+)-paradox phenomenon. In view of the marked influx of Ca2+ into the myocardial cell during Ca(2+)-paradox and the involvement of Ca(2+)-channels in the entry of Ca2+, we determined the status of Ca(2+)-channels by measuring the binding of a Ca(2+)-antagonist, [3H] PN200-110, with membranes obtained from rat hearts perfused with Ca(2+)-free medium. The density of Ca(2+)-channels in the membranes was increased upon perfusing the heart with Ca(2+)-free medium for > 2 min or when the perfusion medium contained less than 25 microM concentration of Ca2+. The increase in Ca(2+)-channel density was attenuated when the hearts were perfused with Ca(2+)-free medium in the presence of a low concentration (35 mM) of Na+ or at low temperature (21 degrees C); two conditions which are known to prevent the occurrence of Ca(2+)-paradox. These results indicate that increased density of Ca(2+)-channels due to Ca(2+)-free perfusion may contribute towards the massive Ca(2+)-influx into the myocardial cell for the induction of intracellular Ca(2+)-overload associated with Ca(2+)-paradox during reperfusion with Ca(2+)-containing medium.

Animals↗
PubMed1990

Subretinal fluid in the diagnosis of posterior scleritis.

The etiology of subretinal mass lesions is very difficult to establish. A 28-year-old man presented to us with an area of choroiditis, which progressed, despite corticosteroid and antibiotic therapy, to an exudative retinal detachment, secondary glaucoma and a painful blind eye. To develop a means of identifying the cause of such lesions, we did a subretinal fluid tap prior to enucleation. Cytopathology showed only inflammatory cells and the final histopathological diagnosis was that of a granulomatous scleritis.

Adult↗
PubMed1984

Role of metal ions in goat carboxypeptidase A-catalysed hydrolysis of acyl peptides.

The carboxypeptidase A purified from goat pancreas has been found to have a molecular weight of 34,600 +/- 300. The enzyme is a zinc-protein and the molar ratio of zinc to enzyme protein is 1:1. Removal of zinc yields an inactive apocarboxypeptidase A. The loss of activity of the native enzyme and restoration of the activity of the apoenzyme run parallel with the zinc content of the protein, thus showing the essentiality of zinc for the enzymatic activity. The exact role of zinc in the enzyme catalysed hydrolysis of the acylpeptides has been investigated after preparing metallo proteins by substituting the zinc of carboxypeptidase A with Co2+, Mn2+, Ni2+, Fe2+, Cd2+, Hg2+, and Cu2+ and determining the kinetic parameters of such metalloproteins. These studies indicate that the metal ion is involved in both binding the substrate and polarising the peptide bond.

Animals↗