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Biomedical subjects

R Mathew

Publications and source records attributed to R Mathew.

At least 73 records · Page 4Linked to original sources
PubMed1989

Cystic fibrosis in Saudi Arabia.

Cystic fibrosis (CF) is generally believed to be rare or nonexistent in Saudi Arabia. The aim of this report is to document the occurrence of CF in Saudi Arabia. Thirteen Saudi children were diagnosed as having CF, evidenced by typical clinical features and elevated sweat chloride concentrations (greater than 60 mmol/l). Duration of symptoms prior to diagnosis varied from 1 month-5 years (mean 23 months). The main clinical manifestations of the children were abdominal distention, failure to thrive, steatorrhoea, hepatomegaly, rectal prolapse and recurrent respiratory infections, often with Pseudomonas aeruginosa. In addition, eight patients with symptoms and a family history highly suggestive of CF, but without confirmatory sweat test results are presented. We hope that this report will increase the awareness of CF and ensure an earlier diagnosis of the disease in Saudi Arabia.

Child, Preschool↗
PubMed1989

Strain differences in pulmonary hypertensive response to monocrotaline alkaloid and the beneficial effect of oral magnesium treatment.

Magnesium therapy has been shown, by us, to attenuate monocrotaline (MCT)-induced pulmonary artery hypertension (PAH), right ventricular hypertrophy and pathological changes in the pulmonary vasculature in 75% of Sprague-Dawley rats. We studied Wistar rats to determine if there was a strain difference in response to MCT and magnesium therapy. Wistar rats were given 60 mg/kg of MCT and studied 3 weeks later, following a protocol similar to that for Sprague-Dawley rats. There was 100% mortality in Wistar rats weighing less than 230 g. The mortality rate in Sprague-Dawley rats of a similar weight range was significantly less (15%). With 40 mg/kg of MCT, Wistar rats developed pulmonary hypertension and right ventricular hypertrophy comparable to those seen in Sprague-Dawley rats administered 60 mg/kg MCT. The percent weight gain over a 3-week period was significantly higher in the Wistar control group than that in the Sprague-Dawley controls (61 vs. 39%; p less than 0.05). Oral magnesium therapy (magnesium aspartate HCl) attenuated pulmonary hypertension and right ventricular hypertrophy in 100% of the Wistar rats studied. A group of Sprague-Dawley rats was given 40 mg/kg of MCT and studied 3 weeks later. PAH and right ventricular hypertrophy in this group were not significantly different from the rats of the same strain injected with the higher dose of MCT. In conclusion, faster growing rats (Wistar) appear to be more sensitive to MCT. Both strains show a significant attenuation of cardiopulmonary changes induced by MCT when treated with oral magnesium.

Animals↗
PubMed1989

Effect of inhalation of insecticide spray on learning and memory in rats.

Acute exposure to insecticide (Baygon-spray; 5 ml/animal/5 min) inhalation in rats did not affect the learning process but produced a significant loss of memory (P less than 0.01 less than 0.001) whereas chronic exposure (one exposure per day for three weeks) produced a significant delay in learning (P less than 0.05) and memory (P less than 0.01). Acetylcholinesterase activity in brain after acute and chronic exposure declined significantly (P less than 0.01) during the learning process but returned to normal after 24 hr.

Acetylcholinesterase↗
PubMed1988

Magnesium aspartate hydrochloride attenuates monocrotaline-induced pulmonary artery hypertension in rats.

1. The effect of oral magnesium aspartate hydrochloride on monocrotaline (MCT)-induced pulmonary arterial hypertension was evaluated in rats. 2. A single subcutaneous injection of MCT, a pyrrolizidine alkaloid of plant origin, induces significant morphological changes in pulmonary vessels, pulmonary arterial hypertension and right ventricular hypertrophy in rats by 3 weeks. 3. Two groups of rats (Mg2+ control and Mg2+ + MCT) were started on oral Mg2+ (15.4 g/l magnesium aspartate hydrochloride dissolved in deionized water) 2 weeks before the MCT injection. The rest were given deionized water. At the start of the experiment, the control groups (deionized water and Mg2+) were given normal saline subcutaneously; the other groups (deionized water and Mg2+) were given MCT (60 mg/kg) subcutaneously. 4. Pulmonary artery pressure, right ventricular hypertrophy, lung pathology, organ weights and serum electrolytes were assessed 3 weeks after a single subcutaneous injection of MCT. Seventy-five per cent of the rats treated with MCT and oral Mg2+ (12 out of 16) showed significant reduction in pulmonary arterial hypertension, arterial pathology and right ventricular hypertrophy. 5. Our data indicate that Mg2+ attenuates experimentally induced pulmonary hypertension, possibly either by modulating the intracellular Ca2+ level and/or by directly affecting the pulmonary endothelial cell-smooth muscle cell complex involved in metabolism and maintenance of pulmonary vascular resistance.

Animals↗
PubMed1988

Magnesium and the lungs.

Recently, there has been considerable interest generated in the possible importance of magnesium ions (Mg2+) in the regulation of bronchial smooth muscle tone and pulmonary vascular tone. These factors have aroused interest in the possible utilization of Mg salts in the treatment of lung diseases (e.g., asthma, allergies, and pulmonary hypertension). Evidence is reviewed which indicates that Mg2+ can influence bronchial vasomotor tone, both indirectly and directly, as well as pulmonary vascular muscle contractility, mast cell granulation and neurohumoral mediator release. In addition, new experimental data suggest that Mg2+ influences a variety of lung structures and chemicals (e.g., capillary endothelial cell integrity, number of type II epithelial cells, surfactant, etc.). Surprisingly, pulmonary arterial muscle cells have a lower Mg content compared to other types of blood vessels and the myocardium, which might point to the vulnerability of the lung vasculature to lower than normal dietary intake of Mg. Several clinical reports point to the salutary actions of Mg2+ in asthma and asthma-like conditions. Very recent experimental findings in rats indicate that Mg2+ treatment can prevent development of experimental chemically induced pulmonary hypertension. Hypoxic pulmonary vasoconstriction has been reported to be attenuated by Mg2+. Although it is not clear as to whether dietary Mg2+ deficiency plays a role in development of some asthma-like conditions or pulmonary hypertension, Mg salts certainly appear to be potentially useful therapeutic avenues for these conditions and should be thoroughly investigated, both from clinical as well as experimental points of view.

Female↗
PubMed1985

Nephrocalcinosis due to primary hyperoxaluria: case report from Saudi Arabia.

Two Arab siblings with nephrocalcinosis and renal failure secondary to primary hyperoxaluria are presented. Percutaneous renal biopsies obtained from both siblings showed marked oxalate deposition in the renal medulla. Primary hyperoxaluria should be considered in the differential diagnosis of renal failure in infancy and early childhood especially when evidence of obstructive uropathy is lacking.

Child, Preschool↗
PubMed1978

Idiopathic atrial flutter in infancy: a review of eight cases.

The experience of three institutions in the management of atrial flutter in infants under 2 years of age without associated heart disease is reviewed. Five babies with neonatal onset were treated with digoxin and had uncomplicated resolution of their arrhythmia, although one continued to have episodes of paroxysmal supraventricular tachycardia for six years. Two of the three older infants required DC cardioversion for complications after quinidine was substituted for digoxin therapy. Digoxin continues to be the preferred initial therapy for non-acutely ill patients; those showing signs of cardiac decompensation should be converted with DC countershock.

Atrial Flutter↗
PubMed1977

Cardiac function in total anomalous pulmonary venous return before and after surgery.

Cardiac performance was evaluated in 12 infants with isolated total anomalous pulmonary venous return. Four had significant pulmonary venous obstruction and severe pulmonary hypertension (group A). Eight had no obvious venous obstruction, and the pulmonary pressures were lower (group B). In all subjects, right ventricular end-diastolic volume was increased (197% of predicted normal) and its ejection fraction was normal. Left ventricular volume was, generally speaking, still in the normal range (87% of predicted normal); however, its ejection fraction was reduced (0.57 vs normal of 0.73) and left ventricular output was low (3.08 L/min/m2 vs normal of 3.98). Left atrial volume was consistently small (53% of predicted normal) with an appendage of normal size. The infants in group A had smaller chamber volumes/m2 BSA than those in group B. Left atrial function was abnormal, characterized by reduced reservoir function and a greater role as "conduit" from right atrium to left ventricle. Left atrial size was not found to be critical in the surgical repair of TAPVR. Cardiac function is restored to normal following surgery.

Angiocardiography↗
PubMed1976

Right ventricular mass estimation by angioechocardiography.

A combined angiocardiographic-echocardiographic method for estimating right ventricular wall mass is described. Biplane cineangiocardiograms are analyzed for ventricular volume in end-diastole, and wall thickness is determined from echocardiograms obtained with a high frequency transducer and strip chart recorder, The intracavitary and the external surface volumes of the ventricle are derived, and the difference multiplied by 1.050, the specific gravity of myocardium. Excellent correlation was observed between right ventricular wall mass and body surface area in normal children (r = 0.93). The mean right ventricular mass was 44.5 g/M2 as compared to 78.1 g/M2 for the left ventricle, corresponding mass/EDV values were 0.48 g/cm3 and 1.26 g/cm3, respectively. In isolated right ventricular pressure overload, the increase in right ventricular mass is chiefly due to the increase in wall thickness; in volume overload, it is due mostly to the increase in chamber volume,

Adolescent↗
PubMed1976

Comparative response of right and left ventricles to volume overload.

The cardiac volume data of 49 normal children were compared with those of 23 with secundum atrial septal defect and 24 with patent ductus arteriosus. Significantly smaller ventricular end-diastolic volumes were observed in the normal infants than in older children (right ventricle 53.9 versus 75.5 cm3/m2; left ventricle 46.7 versus 63.6 cm3/m2). "Distensibility" of the right ventricle (DRV), left ventricle (DLV) and left atrium increased normally with age. DRV and DLV were similar shortly after birth; thereafter, DRV increased more rapidly than DLV (mean DRV 12.7; mean DLV 7.8 cm3/m2 per mm Hg, P less than 0.001). In both atrial septal defect and patent ductus arteriosus, the ipsilateral (involved) ventricles had increased volume, increased output, normal ejection fraction and increased distensibility. The contralateral (left) ventricle in atrial septal defect was smaller than normal (39.6 versus 49.7 cm3, P less than 0.001), and had a smaller ejection fraction (0.63 versus 0.71, P less than 0.01) and output (3.70 versus 4.57 liters/min per m2, P less than 0.005). In contrast, the contralateral (right) ventricle in patent ductus arteriosus remained normal. Left atrial maximal volume was larger than normal in atrial septal defect (46.6 versus 35.9 cm3/m2, P less than 0.001). The left atrial and left ventricular volumes in patent ductus arteriosus were, respectively, 152 and 142 percent of normal, indicating comparable response to the volume load. The left head changes in atrial septal defect may be related both to a functionally restrictive defect and to the difference in distensibility of the ventricles.

Adolescent↗
PubMed1975

Hemodynamics and annuloplasty in isolated mitral regurgitation in children.

Isolated mitral insufficiency in children is quantitated angiographically by comparing the stroke volumes of the right ventricle and left ventricle. The disease results in greater enlargement of the left atrium than of the left ventricle and is accompanied by a significant increase in left atrial "distensibility." Right and left heart pressures may be normal or may be increased; they tend to be elevated in the group with regurgitant fractions of over 50%. Annuloplasty results in marked clinical and hemodynamic improvement and may even be corrective.

Adolescent↗
PubMed1975

Right juxtaposition of the atrial appendages.

We present an infant with right-sided juxtaposition of atrial appendages who had open heart surgery for ventricular septal defect and patent ductus arteriosus. Of 12 cases thus far reported, ventricular d-loop was observed in nine, and normal position of great vessels in four. Contrary to previous views, this condition may not be accompanied by severe conotruncal anomalies.

Adolescent↗