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Biomedical subjects

M Singh

Publications and source records attributed to M Singh.

At least 991 records · Page 55Linked to original sources
PubMed1985

Helminthiasis, mite-allergy and IgE in a homogenous tropical population.

Of 77 eosinophilic male adolescents studied, 12% were found to have helminthiasis and high circulating serum levels of IgE to Dermatophagoides pteronyssinus. This shows that worm-infested individuals can still mount high IgE responses to atopic non-helminthic allergens. The total serum IgE levels of these individuals were not significantly different from those with helminthiasis only, suggesting that there may be some form of repression of helminth-induced non-specific IgE in the presence of atopy; alternatively, allergen-related IgE may be repressed when an individual is worm-infested.

Adolescent↗
PubMed1985

Clinical pattern of vitiligo in Libya.

Patients with vitiligo attending the polyclinics of Benghazi during a 9-month period were reviewed. The proportionate case ratio was 0.33% of all skin cases. The mean age at onset of the disease was 19.38 years; mean age at reporting the disease was 23.06 years. There was more frequent involvement of exposed parts in men compared with women. Vitiligo areata responded better to treatment. The history did not confirm the genetic predisposition of the disease. Association with known autoimmune disease is reported.

Adolescent↗
PubMed1985

Biotransformation of dehydroabietic acid with resting cell suspensions and calcium alginate-immobilized cells of Mortierella isabellina.

Mortierella isabellina ATCC 38063 is a zygomycete capable of hydroxylating fish-toxic resin acids which occur in certain pulp mill effluents to nontoxic metabolites. Addition of dehydroabietic acid (1) (80 mg/liter) to a freshly inoculated culture of M. isabellina in dextrose-yeast extract broth resulted in precursor disappearance in 28 to 30 h. During growth phase, hydroxylation occurred at C-2, whereas hydroxylation at C-15 and C-16 commenced with onset of stationary phase. Alternatively, 1 added to stationary-phase culture (40 mg/liter) disappeared within 2 h and hydroxylation occurred concurrently at C-2, C-15, and C-16. Enzymatic activity of stationary-phase culture was totally cell associated and was present despite the absence of 1 during the preparatory growth phase. Resuspension of mature fungi as free mycelia or immobilized in calcium alginate beads did not diminish the effectiveness of the biotransformation, although two new metabolites, 15-hydroxy-8,9,11,12-tetradehydro-7,8-dihydroabietic acid (5) and 16-hydroxy-8,9,11,12-tetradehydro-7,8-dihydroabietic acid (7) were formed. Immobilized mycelia retained hydroxylase activity for greater than 110 days whether or not they were challenged with fresh 1 on a regular basis. In this respect they are more long-lived than resuspended free mycelia are.

Abietanes↗
PubMed1985

Evaluation of the common conditions associated with eosinophilia.

In an eosinophilic population of 47 boys of the same age, a large proportion (92%) were helminth infested or atopic, or both, compared with 36% of 36 controls. The methods used to detect these conditions were not costly or elaborate, except for the radioallergosorbent test, which was used to measure concentrations of circulating IgE antibodies to atopic allergens. It is suggested that an economical approach to detect helminthiasis and atopy in cases of eosinophilia is adopted using the methods employed here, with skin prick tests replacing the radioallergosorbent test.

Adolescent↗
PubMed1985

Ventilatory thresholds during a graded exercise test.

38 healthy male volunteers were administered a graded exercise test during which selected respiratory gas exchange variables were monitored. In each case, two distinct ventilatory thresholds were observed. The first threshold was detected by the power output at which the VE/VO2 ratio and FEO2 reached a minimum. The mathematical relationship between these two variables was such that at power outputs above this threshold, hyperventilation with respect to oxygen consumption had to occur. The second threshold was detected by the power output at which the VE/VCO2 ratio reached a minimum and the FECO2 reached a maximum. These two variables were related in a manner such that at power outputs above this threshold, hyperventilation with respect to carbon dioxide production had to occur.

Differential Threshold↗
PubMed1985

Alcohol and the integrity of the pancreas.

Alcohol may affect the integrity of the pancreatic parenchyma, as seen in alcoholic pancreatitis, some cases of chronic alcoholism without clinical pancreatitis, and experimental studies. The composition of pancreatic juice may reflect some of these changes. One type of parenchymal alteration is the loss of differentiative features of acinar cells, so that they take on the characteristics of ductular cells. Concomitant fibrosis completes the formation of the tubular complexes found in association with alcoholic chronic pancreatitis. Sustained alcohol intake may produce the accumulation of lipid droplets in parenchymal cells, some of which may be shown to be within the rough endoplasmic reticulum of acinar cells. Epithelial cells may undergo mucous metaplasia. The epithelial-basal lamina barrier frequently is breached in the area of intraluminal aggregates, with or without obvious inflammation in the immediate area. Loss of barrier function may lead to interaction among components of the external compartment (lumen) and the internal compartment (stroma). Increased levels of blood proteins and glycosaminoglycans in the juice, enzyme activation, fibrin formation, and complement activation are potential consequences of barrier loss. Increased lactoferrin levels could result in part from the activity and degranulation of polymorphonuclear leukocytes.

Alcoholism↗
PubMed1985

Type B atrial receptor discharge increases on opening a nonhypotensive arteriovenous shunt in the dog.

A vagovagal cardioacceleratory reflex is activated when an arteriovenous (a-v) shunt is opened in the dog. However, the receptors which initiate this reflex have not been localized. Type B atrial receptor excitation was considered to be a major component of this reflex. The effect of opening a femoral nonhypotensive a-v shunt (i.e., shunt open plus infusion of blood to compensate for the resultant fall in mean arterial and pulse pressure) on type B atrial receptor discharge and heart rate was therefore studied in seven anesthetized, artifically ventilated dogs with beta-adrenergic blockade. Right atrial and aortic blood pressures, heart rate, and type B atrial receptor discharge was studied before and after opening a femoral a-v shunt. On opening the a-v shunt there was a significant increase (44%) in the average activity of type B atrial receptors and a small, but significant (6.8%) increase in heart rate. A significant linear positive correlation was observed between the change in activity of type B atrial receptors and the shunt flow. The results suggest that type B atrial receptors may be one of the receptor groups that initiate this vagovagal reflex.

Afferent Pathways↗
PubMed1985

Effect of cyclic nucleotide phosphodiesterase regulators on isolated rat uterus: with observations on their mechanism of action.

The effect of PDE regulators on isolated rat uterus and their probable mechanism of action was investigated. The potassium chloride-induced contracture was enhanced by imidazole (3.67 X 10(-3)M) and potassium bicarbonate (1.5 X 10(-2)M). In contrast, imidazole (pH adjusted with potassium dihydrogen orthophosphate or HCl) produced a biphasic effect, i.e. initial transient relaxation followed by a sustained contracture. A similar biphasic effect of imidazole was observed in uterine preparations suspended in calcium free K2SO4-Ringer, but in preparations which were allowed to equilibrate to a new base line, it produced sustained contracture. The imidazole-induced increase in contracture appears to be mediated through increased influx of calcium. Phosphodiesterase (PDE) stimulation plays only a minor role, if any. The transient relaxant effect of imidazole may be due to inhibition of thromboxane synthetase and the resultant decrease of intracellular calcium release. The relaxant effect of PDE inhibitors (aminophylline, papaverine, diazoxide), catecholamines and db-cyclic AMP on the K2SO4-Ringer and calcium chloride induced contracture was antagonized by imidazole (pH adjusted with HCl). This inhibitory effect of PDE inhibitors may be mediated through the altered membrane permeability to calcium.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1985

Diphtheria in Afghanistan--review of 155 cases.

During the 3-year study period, 155 culture-positive cases of diphtheria were reviewed at the Institute of Child Health, Kabul. They comprised 0.6% of hospital admissions due to medical disorders in our institute. About 80% of patients belonged to an age group of 1-10 years and only two patients were less than 1 year old. The male to female ratio was 1.3:1. There was no history of previous vaccination against diphtheria in 96.7% of patients. In the majority of patients faucial diphtheria was diagnosed (77.4%), followed by laryngeal (16.1%) an combined pharyngolaryngeal (6.5%). Clinical presentation was with a mild to moderate degree of fever, sore throat, cervical lymphadenopathy, toxaemia, tachycardia and a characteristic thick greyish-white membrane. The main early complications were laryngeal obstruction (35), myocarditis (18), shock (3), polyneuritis (3) and renal failure (2). The overall case fatality rate was 19.3%. Prognosis was unfavourable in patients with laryngeal diphtheria when there was a delay of more than 4 days before reaching the hospital and if there was a delay in relieving laryngeal obstruction by tracheostomy. Outcome was unrelated to the age of the patient.

Adolescent↗