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Biomedical subjects

H van Urk

Publications and source records attributed to H van Urk.

117 records · Page 7Linked to original sources
PubMed1978

Selective arterial embolization for control of traumatic pelvic hemorrhage.

Operative techniques for control of massive extraperitoneal bleeding after pelvic trauma have been disappointing. Extensive blood supply by ample collaterals alledgedly is responsible for the failure of proximal ligation of hypogastric arteries. Angiography has proved to be a valuable technique in the diagnosis and treatment of pelvic vascular injuries. Three patients are reported in which the diagnostic and therapeutic applications of angiography with subsequent embolization enabled the surgeon to avoid a difficult and possibly frustrating exploration. In addition, it provided an accurate indication for surgical intervention in one patient.

Adolescent↗
PubMed1978

Compensatory hyperplasia with increasing loss of renal mass.

When a rat with two kidneys is cross-circulated with an anephric rat, compensatory renal hypertrophy occurs as indicated by an increased ratio of RNA to DNA within 6 hours and an increased ratio of kidney weight to body weight within 12 hours. Removal of three kidneys between the rats further increases residual renal mass and RNA/DNA after 24 and 48 hours of cross-circulation as compared with results of removing two kidneys. Trinephrectomy triples the mitotic index and doubles the proliferative index. Increasing the magnitude of renal loss causes appreciable hyperplasia as well as increasing the magnitude of compensatory renal hypertrophy.

Animals↗
PubMed1975

Rapid reversal of compensatory renal hypertrophy after withdrawal of the stimulus.

The permanence of the early phases of compensatory renal hypertrophy was tested by interrupting vascular parabiosis between an anephric rat and a normal rat after 48 hours. At the time of interruption, the weights and the ratio of ribonucleic acid (RNA) content to deoxyribonucleic acid (DNA) content of the kidneys were the same as those of the remaining kidney in a single rat subjected to unilateral nephrectomy, previously reported. Within 12 hours after parabiosis was stopped, renal mass and nucleic acid concentrations returned to normal. Compensatory hypertrophy could be produced again by unilateral nephrectomy. Regression of the early phase of compensatory hypertrophy appears to be faster than muscular atrophy produced by disuse or denervation. Compensatory hypertrophy can be activated at least twice.

Animals↗
PubMedDate not supplied

Dobutamine-atropine stress echocardiography in elderly patients unable to perform an exercise test. Hemodynamic characteristics, safety, and prognostic value.

OBJECTIVE: To establish the hemodynamic effects, safety, and prognostic value of dobutamine-atropine stress echocardiography in patients 70 years of age or older. DESIGN AND SETTING: Observational study at a university hospital. PATIENTS: One hundred seventy-nine patients (mean age, 75 years; range, 70 to 90 years) referred for chest pain (n = 73) or preoperative risk assessment for major vascular noncardiac surgery (n = 106). MEASUREMENTS: All patients underwent clinical evaluation and dobutamine-atropine stress test. RESULTS: One hundred seventy-nine stress tests were performed. Test end points were the target heart rate (85% of theoretical maximum heart rate), reached in 165 tests (92%); inadequate echo images, two tests (1%); and side effects, 12 tests (7%). Side effects that caused a premature end of the test were severe chest pain (n = 5 [2.8%]), electrocardiographic changes (n = 1 [0.6%]), hypotension (n = 2 [1.1%]), chills (n = 2 [1.1%]), and cardiac arrhythmias (paroxysmal atrial fibrillation) (n = 2 [1.1%]). New wall motion abnormalities as a marker of myocardial ischemia occurred in 50 tests (28%). No death or myocardial infarction occurred during the test. Perioperative events occurred in 12 patients (four cardiac deaths, three myocardial infarctions, and five episodes of unstable angina). During 16 +/- 6 months (mean +/- SD) of follow-up of 166 patients, 22 cardiac events occurred (eight cardiac deaths, four myocardial infarctions, and 10 episodes of unstable angina pectoris). By multivariate regression analysis, only perioperative cardiac events (odds ratio, 51; 95% confidence interval, 5.8 to 454) and late cardiac events (odds ratio, 5.2; 95% confidence interval, 2.0 to 14) were correlated with new wall motion abnormalities during stress. CONCLUSION: Dobutamine-atropine stress echocardiography is a feasible and safe test for assessing elderly patients with suspected and/or proven coronary artery disease, providing useful prognostic information for perioperative and late cardiac risk with relatively few side effects.

Aged↗