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Biomedical subjects

R David

Publications and source records attributed to R David.

At least 127 records · Page 7Linked to original sources
PubMed1988

Effect of changing medication regimens in glaucoma patients.

When glaucoma medication fails to adequately control intraocular pressure (IOP), a second medication is frequently added. Before adding a second drug to patients whose IOP was no longer controlled by 0.5% timolol, we tested the effect of switching to another beta blocker, levobunolol (0.5 or 1%). We also evaluated the effect of study participation on compliance in the control group continuing to receive 0.5% timolol. In each treatment group, the IOP of approximately 30-40% of the patients was successfully controlled for the 3-month study period. The remaining patients did not exhibit significant pressure reductions and were dropped from the study within 2 weeks. We concluded that (1) the results of 'switch' studies without a control group must be interpreted carefully, and (2) the initiation of a 'new regimen' with an equieffective beta blocker may be sufficient to increase compliance and thereby control IOP.

Aged↗
PubMed1988

Epidemiology of retinal vein occlusion and its association with glaucoma and increased intraocular pressure.

A population-based study found an overall incidence rate of symptomatic retinal vein occlusion (RVO) in a 4-year period to be 2.14 per 1,000 in the 40 years and over age group. When cases found among glaucoma clinic patients were separated from the remainder of the population there was marked difference in the incidence rate of RVO in the same time period (1.85 and 17.3 per 1,000, respectively). The rate of RVO increased significantly (p less than 0.001) with age in the general population from 0.93 per 1,000 among persons under 64 years of age to 5.36 per 1,000 among persons over 65. The increase in the rate of RVO by age was less dramatic in the glaucoma clinic population. The two populations also differed in the frequency of the occlusion type: the ratio of the rate of branch vein occlusion to central vein occlusion was 3.2:1 in the general population, but equally distributed in the glaucoma clinic population. Persons with increased intraocular pressure and/or glaucoma were found to have a higher prevalence of RVO than persons with no history of elevated intraocular pressure.

Adult↗
PubMed1988

Presence of immunoreactive corticotropin-releasing factor in rat testis.

We attempted to demonstrate the presence of immunoreactive (ir) CRF in rat testis by RIA, and by an immunocytochemical technique. The RIA was performed on 27,000 x g supernatants of phosphate buffer extracts of adult rat testes, and revealed a high concentration of irCRF (51 - 74 ng/g testis), with a clear parallelism to the standard curve prepared with synthetic rat CRF. In contrast, the peripheral blood level of irCRF was extremely low (less than 0.05 ng/ml). Immunocytochemical studies of irCRF revealed strong specific staining in the Leydig cells and germ cells in normal adult rat testis. Epididymal spermatozoa also stained positive. Testicular irCRF fluctuated significantly with age. The levels (mean +/- SD) assayed in 10, 20, 60 and 90-day-old rats were 41.6 +/- 4.7, 8.7 +/- 0.2, 55.5 +/- 3.3 and 71.3 +/- 3.4 ng/g testis, respectively (P less than 0.01). The level was drastically reduced after abdominal translocation of a testis (9.6 +/- 1.3 ng/g testis), and after hypophysectomy (16.7 +/- 1.6 ng/g testis) in adult rats. However, neither hemicastration nor unilateral cryptorchidism influenced the irCRF levels in the contralateral testis. These data suggest a local production of irCRF which may play a role in regulation of Leydig cell function and sperm maturation in testis and epididymis.

Animals↗
PubMed1988

Closed chest cardiac massage in the newborn infant.

The recommended techniques for external cardiac compression during cardiopulmonary resuscitation of the newborn are reviewed. The American Heart Association advises the rescuer to depress the infant's midsternum with the index and forefingers. An alternative recommendation is to encircle the chest with both hands and appose the thumbs on the midsternum. The cases reported here prove the superiority of the latter maneuver over the former in improving cardiac output and systemic blood pressures. The history of external cardiac compression in infants and children is briefly reviewed, further supporting the conclusion that the technique of encircling the chest with thumbs at midsternum is more efficacious and hence the preferred approach to closed chest cardiac massage in the newborn.

Blood Pressure↗
PubMed1987

Adrenal function in thalassemia major following long-term treatment with multiple transfusions and chelation therapy. Evidence for dissociation of cortisol and adrenal androgen secretion.

Eight patients with beta-thalassemia who were given long-term treatment with combined multiple transfusions and chelation therapy underwent adrenal testing. The six male and two female patients ranged in age from 7 to 19 years. Six of eight patients had delayed bone ages and height greater than 2.5 SDs below the mean. Of the six patients more than 13 years of age, two had clinical evidence of isolated adrenarche and only one had evidence of true puberty. Cortisol levels were similar in patients and controls at zero time (10.6 +/- 1.8 micrograms/dL [292 +/- 50 nmol/L] vs 10.8 +/- 1.4 micrograms/dL [298 +/- 39 nmol/L]) and at 60 minutes (26.6 +/- 2.5 micrograms/dL [734 +/- 69 nmol/L] vs 24.9 +/- 1.9 micrograms/dL [687 +/- 52 nmol/L]) after insulin hypoglycemia (all values are the mean +/- SE). During an eight-hour infusion of ACTH, cortisol responses in the patients with thalassemia were not significantly different from those of controls. Baseline levels of the adrenal androgens dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEA-S) were significantly lower in the subjects with thalassemia compared with controls of similar bone age and pubertal status. The prolonged ACTH infusion caused a significant increase in the DHEA level (79.2 +/- 14.7 ng/dL [2.74 +/- 0.51 nmol/L] vs 538.6 +/- 38.1 ng/dL [18.67 +/- 4.79 nmol/L]) and the DHEA-S level (37.5 +/- 10.8 micrograms/dL [1.02 +/- 0.29 mumol/L] vs 70.5 +/- 18.3 micrograms/dL [1.19 +/- 0.50 mumol/L]) in the patients. The patients' peak stimulated levels of DHEA-S were significantly lower than those of the controls, whereas peak levels of DHEA were similar in the patients and the controls. These results indicate that combined multiple transfusions and chelation therapy preserve the integrity of the ACTH-cortisol axis in patients with thalassemia. The reduced levels of adrenal androgens, short stature, and delayed puberty noted in our patients suggest, however, that alternative approaches to the therapy of thalassemia are needed.

Adolescent↗
PubMed1987

Epidemiology of intraocular pressure in a population screened for glaucoma.

This study evaluated the association between intraocular pressure and various sociodemographic characteristics, ocular findings, and cardiovascular risk factors in a population screened for glaucoma. A total of 2594 subjects older than 40 years residing in three urban areas of southern Israel participated. Of those screened 6.1% had a raised intraocular pressure (IOP greater than or equal to 21). The mean IOP increased with age, was higher among persons born in Africa or Asia than those born in Europe or America, higher among myopes than hypermetropes and among those with an enlarged cup-disc ratio (CDR). Analysis of variance tests indicated that refractive status, CDR, age, country of birth, and diabetes were each independently associated with IOP. In addition, associations between raised intraocular pressure and age, country of birth, myopia, CDR, diabetes, and glaucoma in the family were found.

Adult↗
PubMed1987

Immunocytochemical localization of hFSH as an index of Sertoli cell function in the human testis.

The FSH receptor in the human testis has not been well characterized in vivo. Using an immunoperoxidase technique we have attempted the immunocytochemical localization of FSH in testicular tissue from patients with a variety of disorders including oligo- or azoospermia (N = 6), cryptorchidism (N = 3), and prostatic carcinoma (N = 3). Specific staining for hFSH was observed inside the seminiferous tubule, generally near the basal membrane in all except the cryptorchid patients. Specific staining was also localized in the luminal area of the seminiferous tubule. In most cases, FSH-positive cells were also found in the interstitium, with a minority of the cells being macrophages. The latter were more prevalent in the undescended testes and in orchiectomy specimens from patients with prostatic cancer. The pattern of FSH localization observed in this study probably represents receptorbound hormone, and may reflect damage to the Sertoli cell and its tight junctions. Further study of the changes in receptor distribution as an indication of Sertoli cell malfunction, may be helpful in our understanding of human testicular disorders.

Adult↗
PubMed1987

Treatment of elevated intraocular pressure with concurrent levobunolol and pilocarpine.

Between July 1983 and January 1986, 54 patients with open-angle glaucoma or ocular hypertension were treated for 3 months with 2% pilocarpine hydrochloride (given four times daily) and one of two beta-adrenoceptor blocking drugs, levobunolol hydrochloride (0.5% [17 patients] or 1% [19 patients]) or 0.5% timolol maleate (18 patients), given twice daily. Before entry into the study all patients had had stable intraocular pressure (IOP) with treatment with 0.5% timolol and 2% pilocarpine. Stable IOP was successfully maintained in up to 88% of the patients in the two levobunolol-pilocarpine groups and in 83% of those in the timolol-pilocarpine group. Two patients experienced adverse reactions: one, who received timolol and pilocarpine, suffered blepharoconjunctivitis, and the other, who received 1% levobunolol and pilocarpine, experienced bradycardia. The results indicate that the levobunolol-pilocarpine regimens were as safe and effective as the timolol-pilocarpine regimen in stabilizing IOP.

Adrenergic beta-Antagonists↗
PubMed1987

Osteomyelitis, acute and chronic.

In certain patient populations, osteomyelitis is a significant clinical problem. The judicious use of plain film radiographs and radionuclide bone imaging by the imaging consultant has a critical role in the early detection and diagnosis of osteomyelitis. This complementary imaging approach produces the highest and greatest accuracy in the documentation of skeletal infections. Inadvertent delay in the initiation of appropriate therapy can be obviated utilizing these imaging techniques and undue morbidity averted.

Acute Disease↗