Biomedical subjects
M K Lim
Publications and source records attributed to M K Lim.
Doppler assessment of the interventricular pressure drop in patients with ventricular septal defects.
Doppler ultrasound was used to assess the pressure drop between the ventricles in 109 infants and children (61 less than two years old) with a ventricular septal defect who underwent cardiac catheterisation. The pressure in both ventricles was measured at catheterisation in 103 patients either simultaneously through two catheters (41) or with a single catheter withdrawn across the septum or removed from one ventricle to the other (62). When pressure was measured simultaneously with two catheters (41 patients) the peak to peak and instantaneous gradients showed a maximum difference of 20 mm Hg with levels within 10 mm Hg of each other in 36. Comparison of the difference in the gradients with the average of the measurements demonstrated a tendency for Doppler to underestimate the difference when it was high (greater than 50 mm Hg) and overestimate it when it was low. A Doppler estimate of a low pressure difference between the ventricles indicates pulmonary arterial hypertension and a high one low pulmonary artery pressure, but in the intermediate group Doppler is as yet not sufficiently sensitive to allow selection of those patients who require further investigation and possible operation. Doppler ultrasound was found to be a sensitive method of detecting a very small ventricular septal defect. Thus although Doppler is a very useful means of assessing and following patients with a ventricular septal defect, further studies are required to determine its exact place in clinical practice.
Medical support at the Hotel New World disaster.
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Spontaneous pneumothorax occurring in flight.
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Altitude decompression sickness.
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Traumatic rupture of the pericardium.
Patients with traumatic rupture of the pericardium rarely survive to reach a hospital. Ten cases from the Maryland Institute for Emergency Medical Services Systems and 132 previously published cases are reviewed. Patients were usually men who were victims of violent thoracic trauma. The median age was 40 years. Half of the patients had left pleuropericardial tears; tears of the diaphragmatic pericardium, right pleuropericardium, and superior mediastinal pericardium were less frequent. Associated injuries of the heart or left hemidiaphragm were common. Pericardial rupture was usually discovered during surgical exploration for other indications, but physical or radiographic signs were occasionally present. Repair is indicated for most pericardial tears to prevent herniation of the heart or abdominal viscera.
Amino acids as possible mediators of the intestinal phase of gastric secretion.
In a group of six dogs with Heidenhain pouches, the infusion of a solution of L-amino acids caused identical increases in gastric secretion when given into the jejunum as when administered directly into the portal venous system. Elevations in plasma amino nitrogen were also similar in the two circumstances. In four dogs with Heidenhain pouches and portacaval transposition, a similar infusion caused an identical increase in gastric secretion when given into the jejunum as when given into the peripheral venous system; plasma amino nitrogen levels were almost as high with the jejunal administration as with venous infusion. It is concluded that all, or almost all, of the gastric secretion evoked by amino acids in the canine intestine can be accounted for by the direct effect of absorbed amino acids on parietal cell secretion, with little or no contribution from release of an intestinal hormone.
Amniotic fluid creatinine as index foetal weight.
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Experience with serum magnesium estimations.
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Effect of frusemide on calcium excretion.
After giving oral frusemide (Lasix) to 14 normal volunteers significant hypercalciuria occurred in all of them. This could not be accounted for by any change in glomerular filtration rate, but was possibly due to decreased tubular reabsorption.