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Biomedical subjects

N Mathur

Publications and source records attributed to N Mathur.

At least 19 recordsLinked to original sources
PubMed2002

Persistent chlorinated pesticides and intra-uterine foetal growth retardation: a possible association.

OBJECTIVE: To examine the association between DDT (dichlorodiphenyl trichloroethane) and HCH (hexachlorocyclohexane) exposure and intra-uterine growth retardation (IUGR, <10th percentile of birth weight for gestational age). METHOD: We detected p,p'-DDT, o,p'-DDT, p,p'-DDD, p,p'-DDE and alpha-HCH, beta-HCH, gamma-HCH, delta-HCH in maternal blood, placenta and cord blood, collected at parturition, from mothers with IUGR babies ( n=30) and from those with babies of normal weight ( n=24), using gas-liquid chromatography equipped with electron capture detector ((63)Ni). The adjusted odds ratios (ORs) for these pesticides in mothers and infants were determined by multiple logistic regression. RESULTS: There were statistically significant associations ( P<0.05) between maternal blood levels of alpha-HCH (OR=1.22; 95% CI: 1.02-1.46), gamma-HCH (OR=1.38; 95%CI: 1.05-1.80), delta-HCH (OR=1.61; 95% CI: 1.01-2.54), total HCH (OR=1.07; 95% CI: 1.01-1.13) and p,p'-DDE (OR=1.21; 95%CI:1.03-1.42) and IUGR after adjustment for potential confounders. Also, significant association (P<0.05) between cord blood levels of gamma-HCH (OR=1.14; 95% CI: 1.00-1.31), delta-HCH (OR=1.31; 95% CI: 1.00-1.75), total HCH (OR=1.07; 95% CI: 1.00-1.14) and IUGR were found after adjustment for potential confounders. A significant negative correlation between body weight of newborn babies and p,p'-DDE in maternal blood (r= -0.25; P<0.05) and delta-HCH and p,p'-DDE in the cord blood (r= -0.27 and -0.26; P<0.05) was noticed after gestational age had been accounted for. CONCLUSION: Exposure of pregnant women to organochlorine pesticides may increase the risk of IUGR, which is a contributing factor for infant mortality in India.

Adult↗
PubMed2002

Induced expression of early response genes/oxidative injury in rat pheochromocytoma (PC12) cell line by 6-hydroxydopamine: implication for Parkinson's disease.

The expression of early response gene proteins c-Fos, c-Jun, and GAP-43 and their association with 6-hydroxydopamine (6-OHDA)-mediated oxidative injury were investigated using catecholaminergic PC12 cell line. Significant induction in the expression of c-Fos (P < 0.01), c-Jun (P < 0.001) and GAP-43 (P < 0.05) was observed following 2 h exposure to 6-OHDA (10(-6) M), which persisted during 24 h of observation. The exposed cells exhibited an increase in lipid peroxidation (48, 59 and 33%) along with decreased catalase activity (49, 30 and 13%) and glutathione levels (39, 28 and 16%) following 24, 48 and 72 h exposure, respectively. A concentration-dependent functional impairment of mitochondria as studied by 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and decreased cell survival were also observed following 6-OHDA (10(-4), 10(-5) M) exposure for 24, 48 and 72 h. The results indicate a role of the early response gene in oxidative stress-mediated dopaminergic cell death by 6-OHDA. Similar mechanisms may also be operative in the development of Parkinson's disease, as an increased presence/formation of endogenous 6-OHDA has been reported in Parkinson's patients.

Animals↗
PubMed2001

The effect of smoking and eating habits on DNA damage in Indian population as measured in the Comet assay.

This study was undertaken with the aim of assessing the status of DNA damage in a normal healthy Indian population. The 62 male volunteers in this study belonged to the smoking, non-smoking, vegetarian and non-vegetarian categories, were well educated and aged between 23 and 57 years. The data revealed significant differences in the extent of DNA damage in the smokers versus non-smokers as well as between the vegetarians and non-vegetarians. A significant difference was also observed amongst the different groups of smokers depending on the extent of smoking. An age-dependent effect in DNA damage was also observed. This preliminary study has, for the first time, revealed differences in the extent of DNA damage in the normal Indian population depending on their eating and smoking habits as well as age.

Adult↗
PubMed2001

Hepatic and renal metallothionein induction by an oral equimolar dose of zinc, cadmium or mercury in mice.

The hepatic and the renal subcellular distribution of zinc, cadmium or mercury and induction of tissue metallothionein (MT) at 24, 48 and 72 h following an oral equimolar dose (15 micro;mol metal/kg) of zinc (II) chloride, cadmium (II) chloride or mercury (II) chloride in male albino mice were investigated. There was a moderate increase in hepatic and renal zinc levels mainly in their nuclear mitochondrial fraction (NMF) 24 h post zinc chloride administration. Subsequently, the hepatic zinc increased and the renal zinc declined with time. The zinc-induced hepatic MT level was maximum at 48 h, which decreased slightly thereafter, while there was no marked increase in renal MT level at any time interval. The cadmium was equally distributed in liver and kidney more in their supernatant cytosol fraction (SCF) than in their NMF at 24 h after a dose of cadmium chloride. The cadmium levels showed a decreasing trend in hepatic fractions and an increasing trend in renal fractions with time. The cadmium-induced hepatic and renal MT were substantial at 24 h post cadmium administration, the former decreased thereafter while the latter enhanced at 48 h before declining. The accumulation of mercury in kidney was 1.5 times that in liver, which was localised more in their SCF than in their NMF at 24 h in response to a dose of mercuric chloride. The mercury levels of hepatic and renal subcellular fractions started declining after 24 h and at 72 h they were significantly lower. The induction of hepatic and renal MT was maximum at 24 h after mercuric chloride administration, which declined thereafter concomitant with the decrease in their mercury levels. However, the MT levels in both the organs remained considerably higher than in normal animals at 72 h post exposure. The results show that the accumulation of metal in liver and kidney follows the order: Hg > Cd > Zn and the induction of MT follows Hg > Cd > Zn in liver and Cd > Hg > Zn in kidney. The alterations in zinc and copper homeostasis were more marked in liver than in kidney and follows the order: Hg > Cd > Zn.

Animals↗
PubMed2000

Fulminant pulmonary edema after intramuscular ketamine.

PURPOSE: To report an unusual case of pulmonary edema following intramuscular ketamine administration. CLINICAL FEATURES: An eight-year-old, healthy girl presented for dressing of first degree burns on dorsum of hand. Ten minutes after administration of 125 mg ketamine im, she developed laboured breathing, cyanosis, and bilateral crepitations and arterial blood gas analysis showed PaO2 55 mmHg. There was no evidence of upper airway obstruction. On intubating the trachea, pink frothy fluid emerged from the tube. She was diagnosed as a case of neurogenic pulmonary edema. She was managed with positive pressure ventilation with positive end expiratory pressure, morphine and furosemide. With this treatment she showed a favourable recovery. CONCLUSION: Ketamine was given im to aid burns dressing in this case because it has distinct advantages above the other anesthetic agents including that of being a good analgesic which is absorbed by im route. Its use led to the development of pulmonary edema.

Anesthesia, Intravenous↗
PubMed2000

Clinical, biochemical and neurobehavioural studies of workers engaged in the manufacture of quinalphos.

59 workers exposed to different chemicals during the manufacture of quinalphos, an organophosphate pesticide (OP) and 17 control subjects were studied. Despite similar blood acetylcholinestarase (AChE) levels in both the exposed and control subjects, a significant number of exposed subjects had altered plantar and ankle reflexes. Higher nervous functions such as memory, learning and vigilance were also found to be affected in these subjects. These findings were attributed to chronic low dose combined exposure to different chemicals used/formed in the manufacture of quinalphos. The study raises the doubt that monitoring of AChE alone among subjects engaged in the manufacture of OP pesticides may not be an adequate safeguard as regards to their health.

Acetylcholinesterase↗
PubMed2000

Identification and characterization of mutants with increased expression of hilA, the invasion gene transcriptional activator of Salmonella typhimurium.

Induction of invasion gene transcription and expression of the invasive phenotype of Salmonella strains are regulated by environmental conditions. Experimental evidence indicates that oxygen, pH, and osmotic conditions need to closely resemble those of the host intestinal lumen for invasion gene activation. The hilA gene, encoded on Salmonella pathogenicity island 1 (SPI-1), is a transcriptional activator which is required for invasion and whose expression is modulated by oxygen, pH, and osmolarity. Additionally, hilA is regulated by genetic elements encoded on SPI-1 (hilC/sirC/sprA and hilD), as well as by elements which reside outside of SPI-1 (phoP/phoQ and sirA), although how environmental signals modulate hilA is unknown. In an effort to further characterize the Salmonella invasion gene regulon, we have created and preliminarily characterized 18 Tn5 insertions which result in upregulation of a hilA::lacZY fusion. We have classified the mutations based on location and phenotype into three classes. Six class 1 and six class 2 mutants have insertions in SPI-1 near the invasion gene orgA or the invasion gene regulator hilD, respectively. Six class 3 mutants reside outside of SPI-1 in four different loci. The class 2 and 3 mutations induce overexpression of an episomal hilA::lacZY fusion and significantly increase S. typhimurium invasion of HEp-2 cells in a standard invasion assay. These data implicate new regions of SPI-1 as being involved in the regulation of invasion by S. typhimurium and identify new invasion gene regulators located outside of SPI-1.

Bacterial Proteins↗
PubMed1998

Mobilization of lead by calcium versenate and dimercaptosuccinate in the rat.

1. Calcium disodium ethylenediaminetetraacetate (CaNa2 EDTA) and meso-2,3-dimercaptosuccinic acid (DMSA) individually and in permutation-combination in various doses (0.1, 0.2 and 0.4 mmol/kg bodyweight) were investigated for their efficacy to mobilize lead from vital tissues into urine and faeces and to restore the lead-sensitive biochemical parameters in lead pre-exposed rats with a view to develop the most acceptable treatment regimen for lead poisoning with a minimal loss of endogenous essential elements. 2. The combined therapy was more effective than a single chelator treatment. 3. The combination of 0.2 mmol/kg CaNa2EDTA + 0.4 mmol/kg DMSA caused a lower depletion of zinc, calcium and iron but possessed almost equal capability to that of 0.4 mmol/kg CaNa2EDTA + 0.4 mmol/kg DMSA to produce urinary as well as faecal excretion of lead, to reduce the tissue burden of lead, including that of the brain, and to reverse lead-induced biochemical alterations. 4. The combination of 0.2 mmol/kg CaNa2EDTA + 0.4 mmol/kg DMSA has shown a definite improvement over previously reported combinations in terms of removal of lead from tissues, particularly the brain, restoration of urinary delta-aminolevulinic acid levels and a decrease in the loss of body zinc and is, therefore, recommended for the treatment of lead intoxication.

Animals↗
PubMed1998

Lung function norms in healthy working women.

Two hundred seventy four healthy working women subjects representing different states were subjected to pulmonary function testing to establish linear multiple regression model. Lung functions were considered as dependent variables while age, height and weight as independent variables. Highly significant negative correlation of all lung function parameters with age and positive correlations with height and weight were observed. Females showed a decline of 0.203, 0.199 and 0.210 litres per decade in FVC, FEV0.75 and FEV1.0 parameters respectively. An increase in FVC, FEV0.75 and FEV1.0 values was found to be 0.0217, 0.0132 and 0.0178 litres respectively per unit centimeter increase in height.

Adult↗
PubMed1997

Hair selenium as a monitoring tool for occupational exposures in relation to clinical profile.

Nineteen workers exposed to low levels of selenium (0.047-0.202 mg/m3 air) along with 15 control subjects were studied for clinical, hematological, radiological, and neurobehavioral variables in relation to selenium concentration in hair. The levels of selenium in the hair of exposed subjects (1.44 +/- 0.37 micrograms/g) were significantly higher than those of control subjects (0.78 +/- 0.18 microgram/g). The levels of selenium in the hair of 22 nonvegetarian subjects were found to be significantly higher as compared to 12 vegetarian subjects. Complaints of weakness and/or fatigue were found to be more prevalent in the exposed subjects. The study holds promise that hair selenium may be used as a monitoring tool for low-level occupational exposure to selenium.

Adult↗
PubMed1997

Influence of L-lysine and zinc administration during exposure to lead or lead and ethanol in rats.

Influence of lysine and zinc administration on the lead-sensitive biochemical parameters and the accumulation of lead during exposure to lead or lead and ethanol was investigated in rats. The lead exposure inhibited blood delta-aminolevulinic acid dehydratase (ALAD) activity, increased blood zinc protoporphyrin (ZPP), urinary delta-aminolevulinic acid (ALA), serum glutamic oxalacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), blood and tissue lead levels, and decreased blood and hepatic glutathione (GSH) contents. Some of these effects were enhanced on coexposure to ethanol. The simultaneous administration of lysine and zinc reduced tissue accumulation of lead and most of the lead-induced biochemical alterations irrespective of exposure to lead alone or lead and ethanol. The depletion of endogenous calcium and magnesium owing to lead or ethanol exposure was also prevented by co-administration of lysine and zinc.

Alanine Transaminase↗
PubMed1997

Non-invasive Salmonella typhimurium mutants are avirulent because of an inability to enter and destroy M cells of ileal Peyer's patches.

Salmonella typhimurium initiates infection of a host by invading M cells of Peyer's patches within the small intestine. The ability of the bacteria to invade mammalian cells has been shown to be regulated by environmental conditions, including oxygen concentrations, osmolarity, and growth phase. We have previously created oxygen-regulated Tn5lacZY S. typhimurium mutants that are defective in invasion. We have now identified the invasion genes disrupted by eight of the transposon insertions. These genes encode transcriptional regulators (hilA and invF), type III secretory components (orgA, invG and spaR) and secreted proteins (invC and invD). Examination of the protein-secretion profiles of the non-invasive mutants indicated that each of the mutants was defective in secretion of between one and six proteins. We have also demonstrated that the loss of tissue culture cell invasiveness corresponds to an inability to invade and destroy M cells of Peyer's patches in a murine ligated loop model. Virulence studies, performed in mice, demonstrated that these defects significantly reduced the ability of the mutants to cause murine typhoid fever by an oral route of infection. Virulence by an intraperitoneal route of infection was unaffected. The data indicate that in vitro invasiveness, invasion-protein secretion, and M-cell invasion are critical indicators of S. typhimurium virulence.

Amino Acid Sequence↗
PubMed1995

(Z)-5-(2-thienylmethylene)-2,4-imidazolidinedione.

The major product formed in the thermolysis of 5-diazouracil in thiophene at 423-433 K has been identified as the unexpected compound (Z)-5-(2-thienylmethylene)-2,4-imidazolidinedione, C8H6N2O2S, by X-ray analysis. The molecule is a hydantoin derivative with a thienylmethylene group substituted at the 5-position. The structure is disordered in that the thiophene ring exists in two orientations which are related by an approximate 180 degree rotation about the C(6)-C(7) bond. All of the N and O atoms are involved in an intermolecular hydrogen-bonding network via N-H...O interactions. This network consists of an infinite chain along the a-axis direction and a cyclic trimer arrangement which branches from this chain. The molecules are arranged in the unit cell in pleated sheets which are approximately perpendicular to the c axis.

Crystallography, X-Ray↗
PubMed1995

Modified technique of tension band wiring in flexion injuries of the middle and lower cervical spine.

STUDY DESIGN: This study evaluated simple modifications in tension-band wiring for 52 patients with acute flexion injuries of the middle and lower cervical spine. OBJECTIVE: To determine the usefulness and effectiveness of a modified technique for stabilizing unstable flexion injuries of the cervical spine. SUMMARY AND BACKGROUND DATA: The prevalent surgical techniques of Segal et al and Davey et al fix unstable injuries of the cervical spine by passing two transverse "K" wires through the skin and the spinous process itself, with tricortical iliac crest grafts placed on the sides. This is supplemented with "figure of 8" wiring for long-term stability. METHODS: Fifty-two patients with acute flexion injuries of the cervical spine were fixed with tension-band wiring with slotted grafts placed over the "K" wires and passed through the spinous process, instead of the "K" wire being passed through grafts. RESULTS: Patients free of neurologic symptoms achieved mobility early with the cervical collar. All patients achieved posterior bony fusion. There was no migration or rupture of tension bandwires or tricortical graft in our series. CONCLUSIONS: The modifications used were simple to apply and resulted in good fixation and fusion in patients with acute flexion injuries of the cervical spine.

Adolescent↗
PubMed1995

Socio-economic, environmental and health aspects of farm workers engaged in mango plantations.

A cross-sectional survey of 489 male subjects in the age group 15 to 65 years engaged directly or indirectly in mango cultivation along with 208 control subjects was carried out to find their socio-economic, environmental and health conditions. The conditions like high illiteracy rate (49.5%), poverty (PCI less than Rs 100 per month, 52.2%), poor housing (mud houses, 66.7%) unsafe water supply (78.6%) were prevailing in the surveyed population. The high respiratory morbidity may be attributed to high prevalence of smoking and prolonged inhalation of organic dusts during farming operation associated with illiteracy and poor socio-economic status. Gastrointestinal disorders were related to poor hygienic conditions, smoking and consumption of contaminated water. The symptoms pertaining to CNS, skin and eyes were found to be associated with exposure to pesticides.

Adolescent↗
PubMed1995

Organochlorine pesticide exposure and thyroid function: a study in human subjects.

We examined the serum levels of thyroxine and thyroid stimulating hormone in 103 rural subjects with respect to blood levels of organochlorine pesticide and occupation. We found that 24.3% of study subjects had depleted thyroxine levels in association with significantly lower organochlorine pesticide residues in blood. Sex, nutritional status, thyromegaly, or handling of pesticides in the course of work were not found to be factors contributing to depleted thyroxine levels.

Adult↗
PubMed1994

Influence of dietary iron deficiency on nickel, lead and cadmium intoxication.

The influence of dietary iron deficiency on acute nickel, lead or cadmium toxicity as reflected by the induction of hepatic, renal, and intestinal metallothionein (MT), disposition of the metals and alterations in hematological parameters, was investigated in young rats to ascertain whether the toxic effects of these metals modify under anemic conditions. The administration of Cd induced hepatic, renal and intestinal MT while that of Ni or Pb induced hepatic MT only. While dietary Fe deficiency did not affect MT induction by Cd, it enhanced the synthesis of renal and intestinal MT by Ni and Pb. The accumulation of Pb in liver and kidney and that of Cd in liver only, were enhanced by Fe deficiency; the tissue deposition of Ni remained unaffected by Fe deficiency. The induction of hepatic MT by Ni, Pb or Cd appears to be related to the concomitant rise in the hepatic Zn, Ca and Fe levels in normal rats. However, dietary Fe deficiency increased the hepatic Zn in response to Ni or Cd and the hepatic Ca in response to Pb administration.

Animals↗