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Biomedical subjects

N Garg

Publications and source records attributed to N Garg.

52 records · Page 3Linked to original sources
PubMed1991

Long-term effects of soldering fumes upon respiratory symptoms and pulmonary function.

To evaluate the long-term effect of soldering gases and fumes, and of cigarette smoke on lung function, and the prevalence of respiratory symptoms, a comparative study of spirometric measurements in 57 solderers engaged in acetylene gas soldering of brassware joints in the brass industry (mean exposure: 12.4 +/- 1.1 years) and in 131 controls was performed. The two groups were similar in age, height, smoking habits and social class. The prevalence of respiratory symptoms in the solderers did not differ significantly from that in the unexposed controls (59.6 vs 56.4%). However, solderers who smoked showed higher prevalence of respiratory symptoms than those who did not smoke; a similar trend was observed in the controls. The study failed to demonstrate any association between the respiratory symptoms and length of exposure. The respiratory status of the solderers was unaffected as the results of spirometric measurements of lung function did not show any significant differences between the exposed and the control groups, indicating the absence of an additive effect of cigarette smoking and exposure to soldering fumes.

Air Pollutants, Occupational↗
PubMed1991

Effect of plasma glucose on infarct size in focal cerebral ischemia-reperfusion.

Although hyperglycemia has been shown to consistently exacerbate ischemia brain injury following global or diffuse cerebral ischemia, the effect of hyperglycemia in unilateral focal cerebral ischemia remains controversial. Recent advances in thrombolytic therapy have enhanced the clinical significance of postischemic reperfusion. We studied the effect of plasma glucose on ischemic brain injury in a newly developed focal cerebral ischemia-reperfusion model. Rats allowed free access to food until ischemic insult developed intra- and postischemic hyperglycemia and cortical infarction. Rats fasted for 24 hours had blunted hyperglycemic responses. Infarct volumes were correspondingly smaller. The protective effect of fasting was partially abolished by glucose loading during ischemia to induce intra-ischemic hyperglycemia. Glucose loading immediately or 3 hours after focal cerebral ischemia did not significantly alter the protective effect of fasting. Insulin treatment in fed rats before ischemia also reduced hyperglycemic responses and infarct volume. Timing of insulin treatment was also critical in the reduction of ischemic injury. These findings indicate that plasma glucose during the period of ischemia is an important determinant of brain injury in focal cerebral ischemia-reperfusion and there is a therapeutic window for normalization of plasma glucose to be efficacious.

Animals↗
PubMed1991

An investigation of metal concentrations in blood of industrial workers.

Pigments may contain chromates of zinc and lead, dioxide of manganese, oxides of copper and cobalt, and sulphides of cadmium. Workers engaged in the production of colored glass articles are exposed to fumes and dusts from these pigments. Exposure to these metals through inhalation may lead to a high concentration of these metals in blood. Correlations between biometric characteristics of workers and the blood levels of metals, and between blood levels of different metals were explored. Blood copper and chromium were correlated with occupational history. Significant correlations between blood levels of lead, copper, chromium and manganese were also observed.

Adult↗
PubMed1990

The identification, characterization, sequencing and mutagenesis of the genes (hupSL) encoding the small and large subunits of the H2-uptake hydrogenase of Azotobacter chroococcum.

The structural genes (hupSL) of the membrane-bound NiFe-containing H2-uptake hydrogenase (Hup) of Azotobacter chroococcum were identified by oligonucleotide screening and sequenced. The small subunit gene (hupS) encodes a signal sequence of 34 amino acids followed by a 310-amino-acid, 34156D protein containing 12 cysteine residues. The large subunit gene (hupL) overlaps hupS by one base and codes for a predicted 601-amino-acid, 66433D protein. There are two regions of strong homology with other Ni hydrogenases: a Cys-Thr-Cys-Cys-Ser motif near the N-terminus of HupS and an Asp-Pro-Cys-Leu-Ala-Cys motif near the carboxy-terminus of HupL. Strong overall homology exists between Azotobacter, Bradyrhizobium japonicum and Rhodobacter capsulatus Hup proteins but less exists between the Azotobacter proteins and hydrogenases from Desulfovibrio strains. Mutagenesis of either hupS or hupL genes of A. chroococcum yielded Hup- phenotypes but some of these mutants retained a partial H2-evolving activity. Hybridization experiments at different stages of gene segregation confirmed the multicopy nature of the Azotobacter genome.

Amino Acid Sequence↗
PubMed1989

Study of respiratory impairment among pesticide sprayers in Mango plantations.

Pulmonary function studies were conducted on 489 pesticide workers engaged in spraying operations on mango plantations. These workers were exposed to a variety of organochlorine and organophosphorus pesticides. A reference group consisting of 208 controls, belonging to the same socioeconomic stratum, was taken from the same area for purposes of comparison. The results of the study showed 36.5 and 41.5% prevalence of respiratory impairment in the exposed workers and in the controls, respectively. The most common pulmonary impairment among the exposed subjects (18.8%) and controls (16.9%) was of the restrictive type, followed by mixed ventilatory defect. Bronchial obstruction affected 2.5 and 3.7% of the exposed and control populations, respectively. In a comparison of the prevalence of total respiratory impairment in the pesticide workers and the controls, the nonsmokers did not show any significant difference in this study. The prevalence rate of respiratory impairment showed an increasing trend in different exposure groups (p less than 0.05), thereby clearly indicating a dose effect. The study revealed that occupational exposure to pesticides had a direct bearing on the respiratory impairment identified in the exposed workers.

Adult↗
PubMed1978

Familial spastic paraplegia-clinical and pathologic studies in a large kindred.

Clinical studies of members of a six-generation kindred of familial spastic paraplegia support the diagnostic distinction of a pure form of this autosomal dominant disease. Onset was in the fourth decade or later and symptoms were those of progressive gait difficulties with lower limb spasticity and weakness. Sensor, cerebellar and cranial nerve changes were absent. Pathologic changes in one member were confined to the lateral corticospinal tracts and in the fasciculus gracilis.

Adult↗
PubMedDate not supplied

Dye-affinity techniques for bioprocessing: recent developments.

Textile or triazine dyes play an important role as affinity ligands in protein purification. Each step of the protein purification protocol can be divided into three stages, partitioning between two phases, separation of these phases and recovery of the target protein from the enriched phase. Now developments in dye-affinity techniques are discussed emphasizing the innovations in all three stages of the protein purification process. Dye-affinity chromatography has become a routine step in protein purification. New dyes have been developed and used successfully in both traditional chromatographic mode and new modes like affinity precipitation, polymer aqueous two-phase partitioning or expanded bed chromatography. The specificity of dye techniques has been increased by both purposeful designing of new dyes and decreasing non-specific protein-dye interactions with polymer shielding. One can envisage further development and ramification of dye-affinity techniques in protein purification.

Affinity Labels↗
PubMedDate not supplied

Polymer-shielded dye-affinity chromatography.

Polymer-shielded dye-affinity chromatography is a form of chromatography in which the dye matrix forms complexes with a nonionic, water-soluble polymer such as poly(vinylpyrrolidone) or poly(vinyl alcohol), prior to the column chromatography of a crude protein extract, the idea being that polymer shielding of the dye will prevent nonspecific interactions between the target protein and the dye. The concept of polymer shielding and a strategy for the rational selection of polymers suitable as shielding agents are presented.

Animals↗
PubMedDate not supplied

Poisoning in children: Indian scenario.

The retrospective data on childhood poisoning from eight regional hospitals in India has been reviewed. The demographic features and types of poisonings encountered have been compared. The analysis of the data indicated that pediatric poisonings constituted 0.23-3.3% of the total poisoning. The mortality ranged from 0.64-11.6% with highest being from Shimla. Accidental poisoning was common involving 50-90% of children below 5 years of age and males outnumbered the females. Suicidal poisoning was seen after 13 years of age and was due to drugs and household chemicals. One of the hospitals in Delhi recorded a very high incidence (66.6%) of drug poisoning in children. The drugs consumed belonged to phenothiazines, antiepileptics and antipyretics. Iron poisoning was seen in younger children. Kerosene was one of the causes of accidental poisoning at all hospitals except Shimla and rural Maharashtra were probably wood charcoal is widely used. Pesticide poisoning was more prevalent in Punjab and West Bengal whereas plant poisoning was very common in Shimla. Significant number of snake envenomation has been recorded from rural Maharashtra. Other less common accidental poisonings in children included alcohol, corrosives, heavy metals, rodenticides, detergents and disinfectants. Thus various regions in the country showed some variation in types and frequency of childhood poisoning which could be attributed to different geographical and socio-economic background.

Adolescent↗
PubMedDate not supplied

Plasma lipoprotein(a) levels in patients with pulmonary arterial hypertension.

BACKGROUND: Pulmonary artery hypertension is a common sequelae of a variety of cardiac and lung diseases. Pathogenesis of primary and secondary pulmonary artery hypertension is still debatable. METHODS AND RESULTS: We studied the serum lipoprotein(a) levels in patients with primary (n=27) and secondary (n=19) pulmonary artery hypertension (Eisenmenger syndrome). The results were compared with age and sex matched controls (n=46). We also studied the frequency of high levels of lipoprotein(a) (> 30 mg/dl) in pulmonary artery hypertension. Mean lipoprotein(a) levels were significantly higher in the pulmonary artery hypertension group compared to age- and sex-matched controls (31.60+/-15.49 mg/dl v. 14.66+/-14.7; p=0.0001). All patients were classified into two groups on the basis of their lipoprotein(a) levels (<30 mg/dl and >30 mg/dl). There was a higher frequency of lipoprotein(a) >30 mg/dl in patients of pulmonary artery hypertension v. controls (52% v. 24%; p= <0.001). Younger age, higher functional class, more severe congestive heart failure, shorter duration of symptoms. and more cases of hemoptysis were observed in the group with lipoprotein(a) >30 mg/dl. CONCLUSIONS: High lipoprotein(a) may be a marker and be associated with a more adverse prognosis in severe pulmonary artery hypertension. Larger prospective studies are needed to establish lipoprotein(a) as a risk factor for the development of pulmonary artery hypertension.

Adult↗
PubMedDate not supplied

Role of thrombolytic therapy for stuck prosthetic valves: a serial echocardiographic study.

BACKGROUND: Thrombotic occlusion of a prosthetic valve continues to be an uncommon but serious complication. Intravenous thrombolytic therapy has been proposed as an alternative to surgical treatment, but only in critically ill patients. METHODS AND RESULTS: Forty-one consecutive patients presenting with 48 episodes of prosthetic valve thrombosis (44 mitral and 4 aortic) were treated with thrombolytic therapy under serial echocardiographic guidance. There were 14 male and 27 female patients. The anticoagulation status was inadequate in 89.6% of episodes. Atrial fibrillation was present in 47.9% of episodes. The prostheses involved in these episodes were tilting disc in 45, bileaflet in 2, and ball and cage type in 1. The Sorin prosthetic valve was the most commonly involved. The time interval between valve replacement and thrombosis ranged from 1 month to 108 months (mean 20.4+/-20.6 months). Patients were in New York Heart Association functional class III in 47.9% and in class II in 43.9% of episodes. Thrombolytic agents used were streptokinase and urokinase in 44 and 4 episodes, respectively. The mean duration of thrombolytic therapy was 27.9+/-15.0 hours and the overall success rate was 87.5%. Patients developed peripheral embolism with almost complete recovery in 5 episodes while significant bleeding that required termination of thrombolytic therapy was observed in 2 episodes. Redo valve replacement was done in 3 episodes because these patients did not improve on thrombolytic therapy (all 3 cases were of recurrent prosthetic valve thrombosis and were found to have pannus peroperatively). Three patients died during thrombolytic therapy because of persistent heart failure. Six patients experienced a total of 13 epidoses of recurrent prosthetic valve thrombosis including index episodes (rethrombosis in 5, re-rethrombosis in 1). They were treated with repeated thrombolysis with a success rate of 76.92%. The mean duration of thrombolytic therapy in these episodes was 36.1+/-14.0 hours. CONCLUSIONS: In patients with prosthetic valve thrombosis, intravenous thrombolysis guided by echocardiography is a safe and effective method that may expand the indications for nonsurgical treatment of prosthetic valve thrombosis. By using serial echocardiography, the duration of thrombolytic therapy can be tailored to the patient's requirement for normalization of valve hemodynamics.

Adolescent↗
PubMedDate not supplied

Utility of carotid intimal medial thickness as a screening tool for evaluation of coronary artery disease in pre-transplant end stage renal disease.

BACKGROUND: Coronary artery disease (CAD) is associated with a higher incidence of allograft failure and mortality in patients with end-stage renal disease (ESRD) following renal transplant. AIM: To evaluate the efficacy of using carotid intimal medial thickness (CIMT) to predict the presence of CAD in patients with ESRD, using coronary angiography (CAG) as the gold standard. MATERIALS AND METHODS: This prospective study enrolled consecutive patients with ESRD who underwent CAG as a part of pretransplant evaluation to rule out the presence of atherosclerotic CAD. An operator who was blinded with respect to the results of the CAG, measured carotid IMT in all patients prior to CAG and recorded it on videotape. Two independent observers blinded to the results of CAG measured carotid IMT offline to validate its predictive accuracy as a noninvasive test in predicting the presence or absence of CAD. Measurement of carotid IMT was done on USG B mode 7.5 MHZ probe [HP 5500 andover, Massachusetts]. Student's t-test was used for inter-group comparisons. Pearson correlation coefficient test was used to assess the relation between CAD and various risk factors and carotid IMT. Linear regression analysis was applied to identify independent factors determining presence of CAD. A P value < 0.05 was considered statistically significant. RESULTS: Mean CIMT was significantly higher in those with CAD as compared to those without [0.80+/- 0.06 vs.0.70+/-0.06 mm, P< 0.0001). Patients with CIMT> 0.75 mm were older and had more incidence of diabetes(78% vs. 47%; P=0.001). Only 4/53 (7%) of patients with CIMT< 0.75 mm had CAD, vs. 38/52 (73%) in those with CIMT >0.75 mm. The sensitivity and specificity of using CIMT > 0.75 as a predictor of CAD was 90.47%and 73% and its positive and negative predictive values were 0.73 and 0.92. On multivariate analysis, only CIMT was a significant predictor of CAD. CONCLUSION: Carotid IMT can be used to predict CAD in patients with ESRD. In the absence of other risk factors,patients with IMT< 0.75 mm may not need a pretransplant CAG.

Adult↗