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Biomedical subjects

J Landman

Publications and source records attributed to J Landman.

62 records · Page 4Linked to original sources
PubMed1984

The non-invasive measurement of urea kinetics in normal man by a constant infusion of 15N15N-urea.

A two-pool model is described for the non-invasive measurement of urea kinetics in man. The isotope, 15N15N-urea, was given until an isotopic steady state was reached in urine and the time taken to achieve this is defined. During an isotopic steady state, a comparison was made of the effect of giving the isotope orally, intravenously and intragastrically; no differences were found between the different routes. Measurements of enrichment were made on excretion products in urine. In six normal adults with a protein intake of 200 mg N/kg/d, the urea production rate was 139 +/- 15 mg N/kg/d, 70 per cent of which was excreted in urine. Of the 34 mg N/kg/d produced by hydrolysis of urea in the gastrointestinal tract, 41 per cent was resynthesized to urea, and about 48 per cent was available for other synthetic processes.

Adult↗
PubMed1978

Evaluation of testicular function in prepubertal boys by means of the luteinizing hormone-releasing hormone test.

Luteinizing hormone (LH)-releasing hormone (LH-RH) tests (50 microgram/sq m intravenously) were performed in 112 prepubertal boys ages 13/12 to 11 years (mean +/- standard deviation, 75/12 +/- 16/12 years) suspected of having a testicular disorder because of improperly located testes (77 boys) or hypogonadism (35 boys). Four of the patients were retested within a period ranging from 6 to 16 months. Of the 112 boys tested, 17% were found to have high basal levels of follicle-stimulating hormone (FSH) and 23% were found to have an abnormally high release of FSH after LH-RH administration. Only three patients had abnormally high basal levels of LH and/or elevated LH responses to LH-RH. The basal plasma testosterone levels were found to be normal in all 112 bosy. The fact that plasma FSH levels were elevated more often than LH levels suggests that the tubular elements are damaged more frequently than are the Leydig cells. The surprisingly high incidence of an abnormal response of plasma FSH to LH-RH in boys with mobile testes calls for an increased awareness of the importance of regular examination of these patients until full puberty has been achieved. It is concluded that determination of basal plasma FSH levels and the response to LH-RH stimulation is a useful diagnostic tool for evaluating testicular function in prepubertal boys with suspected pathology of the testes.

Child↗
PubMedDate not supplied

Child rearing in poor urban Jamaica.

Child rearing practices and attitudes were investigated using a questionnaire, among 75 families with 31--60-month-old children in poor suburban Kingston. A pattern emerged of many social contacts, outdoor activities and authoritarian discipline. While teaching and preparation for school were highly regarded, there was little conscious effort to foster cognitive and language development through play. Child rearing appears to reflect the influences of an African heritage, Western urbanization and poverty. Items from the questionnaire were used to devise an index of stimulation. Developmental assessments (DQs) were performed on a subgroup of 45 children. The results correlated positively with the index of stimulation.

Child Development↗
PubMedDate not supplied

Laparoscopic repair of diaphragmatic defect by total intracorporeal suturing: clinical and technical considerations.

OBJECTIVE: The use of laparoscopy in urology is increasing. Tumor of the kidney or adrenal gland and, in some cases, metastatic disease can involve the diaphragm. We describe the application of laparoscopic suturing techniques in the case of diaphragmatic involvement with a renal tumor. METHODS: After resection of the tumor and a small area of the diaphragm, a chest tube was placed under laparoscopic guidance. The tube was kept clamped until the end of the procedure. Decreasing intraabdominal pneumoperitoneum pressure made suturing easier with less tension on the edges of the diaphragmatic incision. Nonabsorbable interrupted horizontal mattress sutures were placed to close the diaphragmatic defect. RESULTS: The repair was uneventful; no intraoperative complications occurred. Extubation was done at the end of the procedure in the operating room. The chest tube was removed on postoperative day 2, and the patient was discharged on postoperative day 3. CONCLUSIONS: Laparoscopic repair of the diaphragm should be commensurate with traditional open surgical principles. In this regard, it is essential that surgeons interested in performing "advanced" laparoscopic oncologic surgery become facile in laparoscopic suturing.

Diaphragm↗