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Biomedical subjects

R A Kaplan

Publications and source records attributed to R A Kaplan.

At least 19 recordsLinked to original sources
PubMed1991

Job involvement and job satisfaction of South African nurses compared with other professions.

The study was designed primarily to compare the work outcomes of job satisfaction and job involvement of South African nurses with those of members of 13 other professional groups in South Africa and with American nurses where data was available. Secondary aims included identifying areas where job satisfaction was particularly low and demonstrating the relative independence of the job involvement and job satisfaction constructs. A questionnaire incorporating the Kanungo Job Involvement Scale and the Short Form of the Minnesota Job Satisfaction Questionnaire was mailed to random samples of people between the ages of 29 and 41 drawn from 14 professional registers. There were 114 nurses in the final sample and 1677 members of other professions. Differences among professions were tested for significance using one-way analyses of variance and Bonferroni ranges tests. South African Nurses were shown to have extremely low job satisfaction relative to American nurses and to other professional groups in South-Africa. By contrast their job involvement was moderately high. The implications of these findings for the medical profession as a whole and for nurses in particular are discussed. The fear is expressed that wide spread dissatisfaction may lead to fewer people entering the profession and highly trained people leaving.

Adult↗
PubMed1990

Affinity labeling of mu opioid receptors by sulfhydryl alkylating derivatives of morphine and morphinone.

After reduction of a disulfide bond at or near the mu opioid binding site in rat brain membranes, incubating membranes with 14 beta-bromoacetamido derivatives of either morphine, dihydromorphine, morphinone, or dihydromorphinone resulted in the irreversible inhibition of mu opioid binding to rat brain membranes. Without the addition of the disulfide bond-reducing reagent dithiothreitol, these affinity ligands bound reversibly to opioid binding sites. Binding to either delta or kappa opioid binding sites was not altered by alkylation of the membranes with the affinity ligands. The percentage of irreversible inhibition of mu opioid binding was dependent on the time and temperature of the incubation of membranes with the affinity ligands and on the concentrations of dithiothreitol and the affinity ligands. Incubating membranes with morphine afforded almost complete protection from alkylation of the mu opioid binding site. Naloxone and the l-isomer levorphanol also protected the site from alkylation, whereas the d-isomer dextrorphan and the kappa-selective opioid U50,488H did not protect the site. The mu-selective peptide [D-Ala2, (Me)Phe4,Gly(ol)5]enkephalin was the peptide that afforded the greatest protection. These studies have shown that, after the reduction of a disulfide bond at or near the mu opioid binding site, this sulfhydryl group can be specifically alkylated, resulting in the affinity labeling of the mu opioid binding site.

Affinity Labels↗
PubMed1985

Infectious peritonitis in patients receiving intraperitoneal chemotherapy.

A total of 32 episodes of infectious peritonitis developed in 90 patients receiving intraperitoneal chemotherapy. Staphylococcus epidermidis was the organism most commonly cultured, accounting for 65 percent of isolates. Result of initial gram stain was positive in 35 percent of cases. The development of fever and abdominal pain as well as rising peripheral and peritoneal fluid white blood cell counts was helpful in the making of a diagnosis of infectious peritonitis. Seventy-five percent of patients were cured with antibiotic therapy alone whereas one quarter also required removal of the semi-permanent catheter. Patients treated with intraperitoneal chemotherapy delivered by dialysis exchange over several days exhibited significantly more episodes of infection than patients treated by a single-drug instillation each month. Although the development of bacterial peritonitis remains a problem during intracavitary chemotherapy, the use of subcutaneous ports and meticulous sterile technique during catheter manipulation will hopefully decrease the risk of occurrence of this potentially avoidable complication.

Anti-Bacterial Agents↗
PubMed1984

Measurement of spatial stability of spark position in burst-mode breakdown with the Nd:YAG laser.

Measurements to determine the precise position of the spark produced by optical breakdown in ocular media with a repetitive sequence of pulses from a Nd:YAG laser have been made. The results show that the location of the spark along the beam axis remains fixed within +/- 10 micrometers (the resolution of the experiment) for pulses with a time separation of 20 milliseconds, indicating that the surgical effects of a sequence of pulses can be cumulative.

Lasers↗
PubMed1981

In vitro stimulation of 25-hydroxycholecalciferol 1 alpha-hydroxylation by parathyroid hormone in chick kidney slices: evidence for a role for adenosine 3',5'-monophosphate.

We studied the effect of parathyroid hormone (PTH) on the in vitro conversion of 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] by kidney slices from vitamin D-deficient chicks. Bovine PTH (bPTH) stimulated 1,25-(OH)2D3 production at low concentrations, with maximal stimulation (65%) at a concentration of 25 ng/ml bPTH in the absence of theophylline. Higher concentrations of bPTH resulted in less stimulation. The addition of 5 mM theophylline to the incubation buffer decreased basal 1,25-(OH)2D3 production but potentiated the stimulation of 1,25-(OH)2D3 production by PTH. Maximal stimulation (170%) was observed with 2 ng/ml bPTH in the presence of theophylline. Maximal stimulation of cAMP production by the kidney slices required 2- to 3-fold larger concentrations of bPTH. However, cAMP by itself stimulated 1,25-(OH)2D3 production, with maximal stimulation (70%) at 10(-7)-10(-5) M cAMP. We conclude that stimulation by PTH of 1,25-(OH)2D3 production can be potentiated by theophylline and mimicked by cAMP. However, such stimulation occurs at PTH concentrations lower than that required for optimal stimulation of adenylate cyclase activity.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗
PubMed1979

The physiologic hyperparathyroidism of pregnancy. Is it primary or secondary?

Controversy exists over whether the increase in maternal serum parathyroid hormone levels observed during the second half of pregnancy is due to autonomous parathyroid function or is secondary to changes in maternal serum ionized calcium levels. In order to study this problem further, 9 subjects were followed serially throughout normal pregnancy. Total serum calcium, ionized calcium, parathyroid hormone (PTH), calcitonin, and albumin levels were measured monthly. Six of these subjects had the studies repeated 6 weeks postpartum. Serum ionized calcium levels were found to decrease from 3.81 +/- 0.12 mg/dl to 3.63 +/- 0.18 mg/dl between 21 and 25 weeks' gestation. This decrease was significant at P less than 0.01. The ionized calcium remained in this lower range until term. A significant return to 3.77 +/- 0.1 mg/dl was observed 6 weeks postpartum. Serum PTH levels showed a significant rise after 21 weeks' gestation (P less than 0.05). No serial change in serum calcitonin was observed during pregnancy, although the mean level of the group was significantly higher than in nonpregnant controls (P less than 0.01). The increase in maternal serum PTH observed during pregnancy appears to be due in part to a decrease in maternal serum ionized calcium.

Adolescent↗
PubMed1978

Selective effects of thiazide on intestinal absorption of calcium and adsorptive and renal hypercalciurias.

The effect of long-term thiazide therapy on the intestinal Ca absorption was measured in 10 well-defined cases of absorptive hypercalciuria with intestinal hyperabsorption of Ca and 8 with renal hypercalciuria ("renal leak" of Ca), many of whom had hyperabsorption of Ca. In most cases of absorptive hypercalciuria, the intestinal hyperabsorption of Ca persisted during treatment, despite restoration of normal urinary Ca. In contrast, the intestinal Ca absorption decreased significantly during thiazide therapy in 7 of 8 patients with renal hypercalciuria commensurate with the "correction" of the renal leak of Ca and secondary hyperparathyroidism. The results support the hypothesis that the intestinal hyperabsorption of Ca in absorptive hypercalciuria may be primary, whereas that in renal hypercalciuria may be associated with the hyperparathyroid state.

Adult↗
PubMed1978

Prostaglandin-mediated hypercalcemia in transitional cell carcinoma of the bladder.

A patient with known transitional cell carcinoma of the bladder and hypercalcemia was evaluated for urinary prostaglandin levels when no bone metastases or elevated parathormone levels could be demonstrated. Urinary levels of prostaglandin E metabolite were assessed in relation to serum and urinary calcium levels during treatment. The serum calcium levels decreased from the 13.0 mg. per cent range whenever the rpimary tumor was manipulated (transurethral resection) or when other treatments directed at the tumor were used (radiation therapy and chemotherapy). Serum and urinary calcium levels, and urinary prostaglandin E metabolite decreased when 3 gm. aspirin were given daily. These data suggest that the somewhat unusual hypercalcemia in our patient was caused by a prostaglandin-secreting transitional cell carcinoma. Prostaglandin-secreting tumors are reviewed herein.

Animals↗
PubMed1978

Metabolism of factor B of serum complement in rheumatoid arthritis.

An increased rate of catabolism of radio-iodinated Factor B has been shown in five out of ten patients with rheumatoid arthritis. Serum levels of Factor B were normal, the increased catabolism being matched by increased synthesis. The patients showing high catabolic rates had more manifestations of extra articular disease than did those with normal catabolic rates and they had higher rheumatoid factor titres. In seven patients, the catabolic rate for Factor B correlated significantly with the rate of IgG catabolism. In this series, the Raji-cell assay for immune complex-like material was in the normal or near normal range in all but one patient.

Adult↗
PubMed1977

Peripheral diabetic neuropathy treated with amitriptyline and fluphenazine.

The pain of diabetic peripheral neuropathy responds poorly to current modes of treatment. We treated eight patients with this disorder whose pain was refractory to standard regimens but who experienced remarkable pain relief within two to five days after treatment with fluphenazine hydrochloride, amitriptyline hydrochloride, or a combination of the two. In four patients whose regimens were discontinued, pain recurred within two days and again remitted on reinstitution of the drug regimens. These findings suggest that fluphenazine alone or in combination with amitriptyline may be of benefit in treating the painful peripheral neuropathy associated with diabetes.

Adult↗