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Biomedical subjects

K Y Mustafa

Publications and source records attributed to K Y Mustafa.

At least 19 recordsLinked to original sources
PubMed1998

Reversible airway obstruction in rheumatic mitral valve disease.

Lung function was studied in 24 patients with advanced mitral stenosis scheduled for mitral valve replacement (MVR), and revealed an obstructive ventilatory pattern. Forty per cent of the patients had a forced expiratory volume in 1 s (FEV1)<60% of that predicted in the preoperative period. Twenty-five per cent of those operated upon showed a similar pattern up to 110 weeks postoperatively. A blind study of the effect of placebo and beta2 agonist (salbutamol) inhalation was performed preoperatively and 6 months postoperatively, to evaluate the reversibility of airflow obstruction in these patients, flow volume curve and body plethysmographic measurement of airway resistance (Rex) and intrathoracic gas volume (VTG). Patients in the pre and postoperative period showed a significant difference between the placebo and the beta2 agonist responses for FEV1, FEV1 as percentage of FVC (FEV1% FVC), peak expiratory flow rate (PEFR), flow rate of 50% of expiratory vital capacity (Vmax50), Rex and VTG (P<0.001). We conclude that salbutamol inhalation improves obstructive impairment in patients with MVR pre- and postoperatively.

Adult↗
PubMed1997

Pathophysiology of bleeding in heat stress: an experimental study in sheep.

Widespread hemorrhagic manifestations commonly occur in patients with severe heat stroke. The pathogenesis of hemostatic disorders in these patients is not fully understood, although it is believed to be multifactorial in origin. The present investigation was designed to study the changes in blood platelets caused by heat stress in an experimental model of five merino sheep. The experiments were performed in two groups of five merino sheep each. In one group the sheep were subjected to a combination of heat (elevated environmental temperature) and exertional stress, and allowed to proceed throughout the experiment until a state of near collapse was reached (Task A). In the other group (Task B) the animals were heated in the same manner as those in Task A and also subjected to exertional heat; however, when the temperature reached 43.6 +/- 0.2 degrees C, the critical core temperature (CCT), they were subjected to evaporative cooling in a climatic chamber. Serial changes in the platelet counts and platelet functions were measured throughout the duration of the experiments. At the core temperature (CT) of 42.1 degrees C and above there was a significant impairment of adhesion of platelets to glass beads. During the early phases of elevation of CT, platelets showed hyperaggregation in the presence of different agonists (such as, collagen, ADP, ristocetin); this was followed by hypoaggregation when the CCT was raised above 43.6 +/- 0.2 degrees C. However, these impairments of platelet functions occurring at elevated CT and CCT were found to reverse to normal within 24 hours after the animals were cooled to 39 degrees C. It was also found that the hyperaggregation of platelets to different agonists induced by raised CT could be partially prevented by prior in vitro treatment of platelets with apyrase, a known enzyme destroying of ADP. The results of these experiments indicate that heat stress induced by exposing merino sheep to elevated controlled temperature directly activates the platelets. This may be an important contributing factor in causing altered hemostasis in heat stroke activated directly by heat. This mechanism may be operating in altered hemostasis in heat stroke.

Animals↗
PubMed1986

Hyperthermia-induced pulmonary edema.

The effects of temperature (37-45 degrees C) on pulmonary edema formation and transendothelial albumin clearance were investigated using isolated perfused guinea pig lungs and bovine pulmonary arterial endothelial cells grown to confluency on a gelatinized membrane. Perfusion of isolated lungs with Ringer-albumin solution at 37 or 41 degrees C for 90 min produced no change in lung wet-to-dry weight ratios (W/D) or in pulmonary capillary pressure (measured by the double-occlusion method). When perfused at 43 degrees C, lung wet weight increased 0.8 +/- 0.4 g over base line (final W/D = 7.43 +/- 0.7) within 90 min. Perfusion at 45 degrees C increased lung weight by 2.7 +/- 0.9 g over base line (final W/D 11.8 +/- 2.3 vs. control value of 5.2 +/- 0.23 at 37 degrees C perfusion) within 60 min. The changes in pulmonary capillary pressure were small (from a base-line value of 4.3 +/- 0.8 to 4.9 +/- 0.4 at 43 degrees C and from a base-line value of 4.9 +/- 0.8 to 5.9 +/- 0.6 at 45 degrees C). The clearance of 125I-albumin (microliter/min) across the endothelial monolayer system increased threefold (from 0.295 +/- 0.035 to 1.048 +/- 0.107) at 45 degrees C, an effect comparable to positive controls of trypsin (from 0.272 +/- 0.046 to 1.595 +/- 0.138) or oleic acid (from 0.278 +/- 0.043 to 0.672 +/- 0.26). An increase in temperature from 37 to 45 degrees C had no effect on the permeability of the gelatinized membrane alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗
PubMed1985

Microprocessor-based system for on-line analysis of respiratory responses to exercise.

A microprocessor-based system was developed for the measurement and on-line calculation of values and derivatives of expiratory variables and their response to exercise. The system accepts analog signals from gas analysers, ECG electrodes and flow transducer, digitizes these signals, calculates values of required parameters and presents results on a video display. The system offers the user various options of logging and data processing. Plots of the values of calculated parameters versus exercise time and correlation between variables can be easily produced by the system. A mass storage unit was available with the system to enable the storage of calculated variables for off-line analysis. Hardcopy of displayed results and plots can be provided by the system.

Computers↗
PubMed1985

Blood coagulation and fibrinolysis in heat stroke.

Blood coagulation and fibrinolysis were assessed in 55 cases of heat stroke who presented with or without bleeding tendencies during the Makkah pilgrimage of 1983. 17 patients were identified to have evidence of disseminated intravascular coagulation (DIC). Bleeders with DIC had a higher incidence of shock and a higher mortality when compared to non-bleeders. Thrombocytopenia and liver cell damage were not limited to cases with DIC. Coagulation factors and serum enzyme studies suggested non-specific tissue damage as the trigger mechanism for DIC possibly proceeding through the extrinsic system of blood clotting. We conclude that the breakdown of haemostasis in heat stroke is multifactorial: thrombocytopenia, liver cell damage and DIC.

Blood Coagulation↗
PubMed1984

Pulmonary function before and sequentially after valve replacement surgery with correlation to preoperative hemodynamic data.

Hemodynamic results after valve replacement surgery are well documented, but there are few follow-up studies on pulmonary function. Pulmonary function and hemodynamic studies were made, preoperatively, in 149 patients with predominant, mitral, aortic or combined mitral and aortic stenosis. A sequential postoperative follow-up of the pulmonary function was performed on 88 patients for as long as 125 wk after valve replacement. All patients had reduced preoperative values for forced vital capacity (FVC), single-breath carbon monoxide diffusing capacity (DLCO), forced expiratory volume in one second, peak expiratory flow rate, and maximal flow after exhalation of 75, 50, and 25% of FVC, and increased total airway resistance, resistance during expiration, and residual volume. The aortic group tended toward more normal values. There was significant correlation between the pulmonary function parameters and the hemodynamic data. In the early postoperative period (10 wk), deterioration of pulmonary function was significant in the aortic group and variable in the mitral and the combined groups; these responses correlated with preoperative hemodynamic and pulmonary function status. Between 10 to 125 wk, all patients showed progressive improvement, especially among those in the mitral group. Patients who died during or soon after mitral valve replacement were found to have significantly lower FVC and DLCO and significantly higher peripheral vascular resistance and cardiothoracic ratio. It is concluded that deterioration in pulmonary function is correlated to severity of cardiac dysfunction, and is reversible late after surgery, except in very advanced cases that have poor prognosis.

Adolescent↗
PubMed1982

Adrenergic and cholinergic induced contractions of tracheal smooth muscle in the rabbit as demonstrated by a new in vivo method.

An in vivo tracheal muscle preparation in the rabbit was developed which enabled us to measure changes in the isometric tension of the trachealis muscle in response to electrical stimulation of autonomic nerves and to i.v. administration of autonomic agonists and antagonists. The preparation was very sensitive to injections of carbachol, and showed graded contractions to stimulation of the caudal end of the cut cervical vagus as frequency and strength of stimulation were increased. Stimulation of the rostral end of the cut cervical sympathetic nerve fibers produced contractions in all preparations. This effect was mimicked by the alpha-adrenoceptor agonist, phenylephrine. The effects of both sympathetic stimulation and phenylephrine were blocked by phentolamine and not inhibited by pretreatment with atropine or propranolol. Sympathetic stimulation produced contractions of the trachealis muscle whether the initial tone was normal or actively increased by carbachol, while adrenaline produced relaxation when the initial tone was high. Using this new in vivo trachealis muscle preparation in the rabbit, we could show that sympathetic stimulation produced contractions of the trachealis muscle. This effect is consistent with the existence of smooth muscle activating alpha adrenoceptors.

Adrenergic Fibers↗
PubMed1979

Serum vitamin A levels of patients with onchocerciasis from two areas of the Sudan.

Two areas of the Sudan known to be endemic to onchocerciasis were surveyed for skin and ocular changes, and serum vitamin A levels in patients and normal controls. In Southern Sudan severe eye lesions and blindness are common complications. In Northern Sudan skin lesions predominate, and no case of blindness was recorded. Serum vitamin A levels were found to be adequate in all groups studied. However, patients from Southern Sudan with both eye and skin lesions due to onchocerciasis had the lowest mean serum vitamin A level. The significance of these findings is discussed in relation to the possible aetiological role of vitamin A deficiency in the pathogenesis of ocular complications of onchocerciasis.

Adolescent↗
PubMed1978

The effects of fasting in Ramadan. 1. Serum uric acid and lipid concentrations.

1. The changes in serum levels of uric acid and lipids during 1 month of starvation-refeeding were measured in sixteen male volunteers. 2. Uric acid levels increased linearly with the duration of the experiment. The increase was positively correlated with the increase in serum triglycerides but not with cholesterol or phospholipids. 3. Triglycerides increased at a faster rate than uric acid implying that the increase in uric acid was secondary to that of the lipid. 4. It was concluded that the purine and lipid synthetic pathways are linked through a common small-molecular-weight effector rather than through the sharing of a common enzyme.

Adult↗
PubMed1977

Spirometric lung function tests in normal men and African ethnic origin.

Measurements of forced vital capacity, forced expiratory volume in 1 sec; and peak expiratory flow were carried out in 623 normal Northern Sudanese, Soutehrn Sudanese, and Tanzanian men 17 of 70 years of age. The widely used prediction formular of these parameters for American, British, and Swedish subjects gave significantly higher values than the observed values in this study. From the results in Northern Sudanese subjects, prediction formulas and nomograms were constructed. They were found to provide accurate predictions for subjects from Southern Sudan and Tanzania. It is therefore confirmed that racial variations in the values of these parameters occur. The present prediction formulas and nomograms are recommended for subjects who are of African ethnic origin.

Adolescent↗
PubMedDate not supplied

An integrated microprocessor-based system enhanced with graphics for the evaluation of slope-ratios and other flow-volume curve parameters.

A microprocessor-based system is developed to measure and analyse flow-volume curves produced from forced expiratory manoeuvres. The system evaluates the slope-ratio parameter and displays it as a scaled plot against fractions of vital capacity together with a scaled plot of the flow-volume curves on a graphic display. Other conventional parameters and their predicted values are also calculated. Freedom is allowed for the operator to select or reject manoeuvres from several runs. The system is easily run and guided even by an operator with no programming knowledge.

Computers↗