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Biomedical subjects

K Suresh

Publications and source records attributed to K Suresh.

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

Hemophilia A: role of FVIIIC/vWF Ag in assisting linkage analysis for carrier detection.

Carrier detection for hemophilia A was carried out in 52 females from 30 families presenting to the Haematology Department AIIMS, using linkage analysis and factor VIIIC (FVIIIC)-von Willebrand factor (vWF) antigen assay. The allelic frequency for the marker Bcl 1 and Xba 1 was 0.58 and 0.54, respectively, for the positive alleles and 0.42 and 0.46, respectively, for the negative alleles. The heterozygosity frequency of Bcl I and Xba 1 was 0.65 and 0.55, respectively. Of the 52 females, 30 were mothers of hemophilic patients and 22 were sisters of hemophilic patients. Of the 30 mothers, positive family history was present in 14. In these patients, the defective X chromosome was tracked in 10, and in four the defective X chromosome could not be tracked because the mothers were homozygous for the marker used. Of the 16 mothers without a family history of disease, three were observed to be carriers based on linkage analysis and reduced factor VIII levels in mother/sister. Possible defective X chromosome was tracked in 11 mothers and five were noninformative because they did not show heterozygosity for the markers used. Using linkage analysis, nine of the 22 sisters were found to be definite carriers, 10 noncarriers, and three were noninformative. It is thus concluded that using Bcl 1 and Xba 1 linkage analysis, carrier status can be definitely ascertained in 50% females and this level of information can be increased to 61.5% by measuring FVIIIC/vWF antigen levels in them.

Chromosome Mapping↗
PubMed2000

Trends and determinants of immunisation coverage in India.

The 20th century has witnessed many important events in the control of infectious diseases that mostly affect children. In addition to the eradication of smallpox, the interruption of poliomyelitis transmission in many countries with a distinct possibility of its eradication by the turn of this century are some of the major achievements. Also, the rates of other vaccine preventable diseases such as measles, pertussis and diphtheria have gone down significantly. The discovery and use of vaccines have made it possible to save approximately 8 million deaths, annually. This is in addition to the reduction in millions of children's suffering and disability. It is now important to build on these gains through adequate utilisation of other vaccines e.g., hepatitis B, typhoid and Haemophilus influenzae type b that are currently available, but in limited use. But, a high level of coverage for any vaccination programme is a pre-requisite to witness the effective reduction of the specific disease against which child population is vaccinated. This paper reviews the coverage levels by surveys in the last 3 years. It has been observed that vaccination coverage levels are falling. Keeping the promises of immunising every child to fulfill his/her right is the need of the hour. To achieve this the major action points are: (a) The need for organising fixed immunisation sessions at the community, where low proportion of sessions are held; and (b) The need to improve demand generation activities where the coverage is poor despite better service availability at the community level. Therefore, the challenge for the next century is to make sure that the enormous impact of vaccines on the health and well-being of the population is maintained as well as expanded. Vaccines that effectively prevent rotavirus diarrhoea, pneumococcal pneumonia, menigococcal meningitis, if made available, could prevent deaths up to two million a year. Research efforts are currently under progress to develop new vaccines against malaria, tuberculosis, shigella-induced dysentery, and Esch coli-induced diarrhoea.

Child, Preschool↗
PubMed1999

Field's stain--a rapid staining method for Acanthamoeba spp.

Acanthamoeba sp. is a free-living amoeba known to cause chronic central nervous system infection or eye infection in humans. Many cases remain undetected for want of a good detection system. We report for the first time a rapid staining method to facilitate the identification of Acanthamoeba sp. using the modified Field's staining technique. A. castellanii, which was used in the present experiment, is maintained in our laboratory in mycological peptone medium (Gibco). The cultures were pooled together and smears were made on glass slides for staining purposes. Different types of stains such as Field's stain, modified Field's stain, Wright's stain, Giemsa stain, Ziehl-Neelsen stain, and trichrome stain were used to determine the best stain for the identification of this amoeba. The concentration of various stains and the duration of staining were varied to provide the best color and contrast for each stain. Acanthamoeba was also obtained from the brain of experimentally infected mice and was stained with various stains as mentioned above to determine the best stain for use in identifying the presence of this parasite in experimentally infected animals. The modified Field's stain gives a very good color contrast as compared with other stains. Furthermore, it takes only 20 s to be carried out using the least number of reagents, making it suitable for both laboratory and field use.

Acanthamoeba↗
PubMed1999

Isolate resistance of Blastocystis hominis to metronidazole.

Isolates of Blastocystis hominis from infected immigrant workers from Indonesia, Bangladesh and infected individuals from Singapore and Malaysia were assessed for growth pattern and degree of resistance to different concentrations of metronidazole. Viability of the cells was assessed using eosin-brillian cresyl blue which stained viable cells green and nonviable cells red. The Bangladeshi and Singaporean isolates were nonviable even at the lowest concentration of 0.01 mg/ml, whereas 40% of the initial inoculum of parasites from the Indonesian isolate at day one were still viable in cultures with 1.0 mg/ml metronidazole. The study shows that isolates of B. hominis of different geographical origin have different levels of resistance to metronidazole. The search for more effective drugs to eliminate th parasite appears inevitable, especially since surviving parasites from metronidazole cultures show greater ability to multiply in subcultures than controls.

Animals↗
PubMed1998

Oxygen supply without gas-liquid film resistance to xanthomonas campestris cultivation

Alternative methods of oxygen supply are of crucial importance, especially in viscous fermentations and shear-sensitive fermentations. A method of oxygen supply that completely eliminates the gas-liquid transport resistance has been presented. The method involves a need-based liquid-phase decomposition of hydrogen peroxide to provide the necessary oxygen. When Xanthomonas campestris was cultivated (viscous cultivation) using this method of oxygen supply, dissolved oxygen (DO) levels were maintained above the setpoint of 50% throughout the cultivation, whereas the conventional cultivation was able to meet culture oxygen demand only for about 6 h in a 72-h fermentation. Furthermore, the maximum specific growth rate and xanthan yields in the novel cultivation were 89% and 169%, respectively, of those obtained in conventional cultivation. A mathematical model was also developed to simulate and predict results in fermentations employing the presented methodology. In addition, studies with HOCl pretreatments indicated that monofunctional catalase may be responsible for the decomposition of H2O2 supplied externally to cells; HOCl pretreatments also increased the tolerance of cells to H2O2. The decomposition kinetics of externally supplied H2O2 was Michaelis-Menten in nature with vmax = 1.196 x 10(-6) M s-1 and Km = 0.21 mM. The catalase concentration was estimated to be 3.4 x 10(-10) mol/g of cells. Copyright 1998 John Wiley & Sons, Inc.

Journal Article↗
PubMed1998

Maximizing the hemodynamic benefit of enhanced external counterpulsation.

BACKGROUND: Enhanced external counterpulsation (EECP) has been demonstrated to be an effective treatment for angina and exertional ischemia in patients with coronary disease. HYPOTHESIS: It is hypothesized that the ability of EECP to enhance the recruitment or development of coronary collaterals in coronary artery disease may be determined by the relative magnitude of diastolic augmentation (DA) and systolic unloading (SU). This study examines the relation between the proposed EECP effectiveness ratio (DA/SU), as assessed by finger plethysmography, and changes in descending aortic flow as assessed by Doppler echocardiography in 15 patients during EECP. METHODS: Varying external cuff pressures (0-275 mmHg) were used to generate a range of DA/SU ratios. The effect on aortic antegrade systolic and retrograde diastolic flow was assessed by Doppler echocardiography to determine whether there was an optimal EECP effectiveness ratio that maximizes the hemodynamic effects of EECP. With increasing DA/SU there was an initial positive linear increase in both systolic and diastolic flow volume. Systolic flow maximized at an effectiveness ratio of 1.5 and diastolic flow at a ratio of 2.0 RESULT: Therefore, effectiveness ratios (DA/SU) in the range of 1.5-2.0 are optimal for maximizing the hemodynamic effects of EECP.

Adult↗
PubMed1997

A putative role for calmodulin in the activation of Neurospora crassa chitin synthase.

The possible role of calmodulin in cell wall formation and chitin synthesis was studied in Neurospora crassa by examining the effects of anti-calmodulin agents on protoplast regeneration and possible associations between chitin synthase and calmodulin related proteins in microsomal isolates. Protoplast regeneration was inhibited by trifluoperazine (> 20 microM), an anticalmodulin agent. Chitin synthase activity in microsomes was associated with that of calmodulin-dependent protein kinase and inhibited by trifluoperazine (100 microM). In vitro activity of chitin synthase was enhanced upon inclusion of calmodulin (300 ng) in the assay mix, 63% over and above the stimulation brought about by trypsin, an activator of the enzyme. Autoradiography studies on microsomal proteins revealed calmodulin-dependent phosphorylation of two microsomal calmodulin-binding proteins (106 and 89 kDa). The results indicate that calmodulin-mediated phosphorylation of specific microsomal proteins may be important in the in vivo activation of chitin synthase.

Calcium-Calmodulin-Dependent Protein Kinases↗
PubMed1996

Isolation and characterization of a copper containing protein from blue cell walls of Neurospora crassa.

Culturing Neurospora crassa in presence of toxic amounts of copper (0.63 mM) resulted in blue coloured mycelia and cell walls. Significant amounts (approximately 45%) of total mycelial copper were associated with cell wall isolates under conditions of copper toxicity. Hence, such blue cell walls were analysed to identify specific ligands involved in copper binding. While decuprification of the blue cell walls with 8-hydroxy quinoline (8 HQ) did not alter their copper binding abilities, similar treatment with EDTA (10 mM) decreased such abilities indicating that EDTA treatment lead to loss of copper binding ligands from cell walls. Treatment of blue cell walls with 8 HQ followed by EDTA resulted in the solubilization of a copper binding protein (relative MW approximately 14 kDa) which was associated with phosphate and carbohydrate moieties. On amino acid analysis, this protein was found to be devoid of free thiol groupings but enriched in acidic and basic amino acids, distinguishing it from classical intracellular metal binding proteins such as metallo-thioneins and phytochelatins that are inducively synthesized under conditions of metal toxicity. The biological significance of the isolated wall-bound copper binding protein, which appears to be a normal constituent of cell walls, is discussed in relation to cytoplasmic metal binding proteins and mechanism(s) adapted by fungi in countering metal toxicity.

Cell Wall↗