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Biomedical subjects

M Mohan

Publications and source records attributed to M Mohan.

At least 55 records · Page 3Linked to original sources
PubMed1993

Epidemiology of Pseudomonas aeruginosa infections in a neonatal intensive care unit.

During the 19-month study period, 48 (2 per cent) of the 2177 neonates admitted to the neonatal intensive care unit (NICU) yielded Pseudomonas aeruginosa growths in blood cultures. All these neonates had clinical and haematological evidences of sepsis. Prominent clinical features included sclerema, violaceus necrotic patches, necrotizing enterocolitis (NEC), conjugated hyperbilirubinaemia, and DIC. Over all mortality was 23 per cent, distinctly higher in premature neonates with RDS. The mean gestational age and birth weights (+/- SD) of these neonates were 36.42 (+/- 2.73) weeks and 2173.34 (+/- 567.33) g, respectively. Approximately half of the total cases had low birth weight. Other adverse perinatal events before the development of sepsis included birth asphyxia (60 per cent), neonatal resuscitation (67 per cent), meconium aspiration syndrome (29 per cent), hyaline membrane disease (8 per cent), prolonged hospitalization (44 per cent), closed incubator care (17 per cent), prolonged intravenous fluids (42 per cent), repeated blood sampling (63 per cent), and umbilical catheterization (4 per cent). Analysis of the trend of Pseudomonas sepsis in our NICU revealed six definite outbreaks (more than two cases) interspersed with occasional (one or two) cases. Six study months, however, remained free of Pseudomonas sepsis. Index case was demonstrable on seven occasions. Bacteriological surveillance of the NICU after onset of initial case/cases revealed statistically significant colonization of resuscitation equipment, baby placement sites, and various cleansing solutions by the same bacterial species (P < 0.05). It is possible that Pseudomonas was introduced to our NICU from transfer admissions from other hospitals since on four occasions index case was the one transferred from outside.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacteremia↗
PubMed1991

Atmospheric dispersion of inflammable substances for estimating vulnerable zones in hydrocarbon industry.

The present study utilizes an operational model as well as simple empirical relationships for estimating hazard zones due to fire, explosion, and toxic vapor cloud dispersion. The empirical relationships are based on giving appropriate weightage to each of the parameters on which the hazard in question (viz, fire, explosion, toxic vapour dispersion) is dependent. Results from these two approaches [i.e., an operational model FLAMCALC of U.K. Health and Safety Executive (HSE) and an empirical model named FIREX] have been compared with the data obtained from the Mexico City disaster in 1984. In general, results from the empirical approach and FLAMCALC are comparable to the observed effects.

Air Pollution↗
PubMed1991

Estimation of vulnerable zones due to accidental release of toxic materials resulting in dense gas clouds.

Heavy gas dispersion models have been developed at IIT (hereinafter referred as IIT heavy gas models I and II) with a view to estimate vulnerable zones due to accidental (both instantaneous and continuous, respectively) release of dense toxic material in the atmosphere. The results obtained from IIT heavy gas models have been compared with those obtained from the DEGADIS model [Dense Gas Dispersion Model, developed by Havens and Spicer (1985) for the U.S. Coast Guard] as well as with the observed data collected during the Burro Series, Maplin Sands, and Thorney Island field trials. Both of these models include relevant features of dense gas dispersion, viz., gravity slumping, air entrainment, cloud heating, and transition to the passive phase, etc. The DEGADIS model has been considered for comparing the performance of IIT heavy gas models in this study because it incorporates most of the physical processes of dense gas dispersion in an elaborate manner, and has also been satisfactorily tested against field observations. The predictions from IIT heavy gas models indicate a fairly similar trend to the observed values from Thorney Island, Burro Series, and Maplin experiments with a tendency toward overprediction. There is a good agreement between the prediction of IIT Heavy Gas models I and II with those from DEGADIS, except for the simulations of IIT heavy gas model-I pertaining to very large release quantities under highly stable atmospheric conditions. In summary, the performance of IIT heavy gas models have been found to be reasonably good both with respect to the limited field data available and various simulations (selected on the basis of relevant storages in the industries and prevalent meteorological conditions performed with DEGADIS). However, there is a scope of improvement in the IIT heavy gas models (viz., better formulation for entrainment, modification of coefficients, transition criteria, etc.). Further, isotons (nomograms) have been prepared by using IIT heavy gas models for chlorine, which provide safe distance for various storage amounts for 24 meteorological scenarios prevalent in the entire year. These nomograms are prepared such that a nonspecialist can use them easily for control and management in case of an emergency requiring the evacuation of people in the affected region. These results can also be useful for siting and limiting the storage quantities.

Accidents, Occupational↗
PubMed1991

Coagulase negative staphylococcal septicemia in newborns.

The case records of 2177 newborn infants admitted in the Neonatal Intensive Care Unit (NICU) from January, 1989, through July, 1990, with positive blood cultures for coagulase-negative staphylococci (C-NS) were evaluated. Seventy four (3.4%) neonates yielded C-NS in blood cultures during the study period. Of these, 58 (2.7%) infants had clinical and hematological features compatible with the diagnosis of septicemia. Remaining 16 babies with positive cultures had no evidence of sepsis, and were designated as "C-NS bacteremia". The age at which positive cultures were obtained differed between the bacteremic and septicemic groups. In bacteremic group, the onset occurred between one to four days of age. In contrast, in septicemic group the range was 6-20 days, with a mean of 10.22 (+/- 3.53) days. More than two third of total cases of C-NS sepsis were premature and low birth weight (LBW). Prominent clinical features included lethargy, poor feeding and fever. Besides this apneic spells were seen predominantly in babies weighing less than 1500 g. Further, before the diagnosis of C-NS sepsis, more than half of neonates had received prolonged intravenous fluid therapy, a quarter had undergone umbilical catheterization and a further quarter needed a ventilator support. Overall mortality in C-NS sepsis was 17.24%, distinctly higher in neonates with RDS and those requiring mechanical ventilation (p less than 0.05). Only 1.34% C-NS isolates were resistant to all routinely used antibiotics and sensitivity was maximum with newer cephalosporins, ciproflox and amikacin.

Bacteremia↗
PubMed1991

Intrauterine growth predictors.

The present study was conducted to construct standards for midarm circumference and midarm/head circumference ratio to identify neonates at risk for metabolic complications and to assess the anthropometric variable which could be used to substitute weight to identify low birth weight neonates. A study of 2925 consecutive live births showed significant correlation (p less than or equal to 0.001) between different anthropometric variables studied. Since midarm circumference (MAC), midarm circumference/head circumference ratio (MAC/HC) and ponderal index (PI) had the least correlation with gestation, these were used as independent markers for gestation. Among these three, MAC had the best correlation with birth weight (r = 0.808). A midarm circumference of less than or equal to 8.6 cm and less than or equal to 7.4 cm had the best sensitivity and specificity for identifying neonates with a birth weight of less than or equal to 2500 and less than or equal to 2000 g, respectively. All the anthropometric variable studied can rule out low birth weight with great accuracy (high negative predictive value greater than 90%).

Arm↗
PubMed1991

Effect of head-up tilting on systolic time intervals in normal young volunteers.

Systolic time intervals (STI) are sensitive indices of myocardial function. Passive tilting is a rapidly reversible and non-invasive method for inducing cardiovascular stress. The present work was conducted to study the effect of graded head-up tilt (HUT) on STI. 20 male medical students were subjected to 30 degrees, 60 degrees and 80 degrees HUT on a tilting table. ECG, phonocardiogram and carotid pulse were recorded simultaneously on Grass polygraph. Electromechanical systole (QS2), left ventricular ejection time (LVET), pre-ejection period (PEP), PEP/LEVT ratio, heart rate (HR) and corrected STI were determined immediately after and at 1, 2, 3, 4 and 5 min after each angle tilt. HUT produced a decrease in QS2 which was more pronounced at higher angle tilt. LVET decreased after 60 degrees and 80 degrees HUT. PEP and PEP/LVET ratio decreased after each angle tilt. These changes in STI can be explained on the basis of sympathetic stimulation-induced increase in the inotropic state of the heart.

Adolescent↗
PubMed1991

Congenital syphilitic hepatitis.

Hepatitis is a known manifestation of congenital syphilis, however hepatitis developing during penicillin therapy is unknown. Ten patients of congenital syphilis were studied and serial liver enzymes were done before and after starting penicillin therapy. Eight of the ten patients developed hepatitis after initiating penicillin therapy. Whether hepatitis in these cases was secondary to toxic reaction to the products of treponemal lysis or an autoimmune reaction needs to be investigated.

Alanine Transaminase↗
PubMed1990

Oxidative stress induced by a copper-thiosemicarbazone complex.

Copper thiosemicarbazones cause considerable oxidative stress. This effect may be related to their cytotoxicity. In the present work, the chemical and cellular properties of a new ligand, pyridoxal thiosemicarbazone (H2T), and its copper(II) chelate (CuT) are assessed. CuT is toxic to cultured Ehrlich ascites tumor cells, producing nearly complete cell kill at drug/cell ratios of 2.5-4 nmol/10(5) cells in a monolayer culture over a 48-h treatment period. This concentration is at least 1 order of magnitude lower than those required for a similar degree of cytotoxicity by H2T or CuCl2. The following observations support the view that activated oxygen species are generated by interaction of CuT with Ehrlich cells: (1) Room-temperature electron spin resonance spectroscopy and atomic absorption measurements show rapid cellular uptake and CuT-thiol adduct formation. (2) Cellular thiol content is reduced. (3) High levels of DNA strand scission result from 1-h treatments of cells by concentrations of CuT that cause growth inhibition and toxicity. (4) The extent of strand scission can be increased by addition of superoxide dismutase and decreased by catalase or DMSO in the treatment medium. Catalase and DMSO do not inhibit the toxic effect of CuT. This suggests that DNA damage is not responsible for inhibition of cell proliferation by CuT.

Animals↗
PubMed1990

Results of penetrating keratoplasty in vascularized corneas.

A retrospective longitudinal study of 105 penetrating keratoplasties for vascularized corneal opacities was done. The results of cases with an etiology of healed trachoma or healed corneal ulcers were compared. The vascularization was graded from Grade I to V depending on the quadrant and type of vascularization. Graft clarity of 2+ or more in cases of trachomatous opacity was achieved in 93% of cases and that after postinfectious opacity in 71.8%. Prognosis was poor in cases where deep vascularization was present in more than two quadrants or more than 180 degrees.

Adolescent↗
PubMed1990

Ultrasonic intrauterine growth curves.

Intrauterine growth was studied by serial ultrasonic measurements of biparietal diameter (BPD), femur length (FL) and abdominal circumference (AC) in 241 normal low risk obstetric patients. These measurements were used to construct normal ultrasonic fetal weight and length curve. The data correlate well with the already established, postnatal weight and length curves after 28 weeks of gestation. The fetal ponderal index curve was compared with postnatal ponderal index curves available. Antenatal recognition of fetal weight, length and ponderal index can be used to evaluate pregnancies at risk for altered fetal growth.

Birth Weight↗
PubMed1990

Campomelic syndrome.

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Abnormalities, Multiple↗
PubMed1990

Bromhexine.

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Adult↗