Biomedical subjects
R Lewis
Publications and source records attributed to R Lewis.
Bronchial hyperreactivity after inhalation of distilled water and saline.
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Prediction of urinary excretion of 131I-orthoiodohippurate.
A new formula is presented for the prediction of urinary excretion at approximately 35 min after injection of 131I-orthoiodohippurate, derived from a large series of normal kidney donors, before and after unilateral nephrectomy, and a few patients with diseases in which there was no evidence of urinary tract obstruction. The best formula was: Expected percent dose excretion at 35 min = 79.3[1-e--(0.004798 X ERPF)] with a standard error of estimate (Sy.x) of 5.2% dose. This value has been particularly useful in clinical practice in the calculation of an excretion index (actual/expected percent dose excretion) which separates various post-transplantation entities and various nephrourologic processes.
Comparative electrophysiologic effects of digoxin in the nonsedated chronically instrumented puppy.
The electrophysiologic effects of acute but not chronic administration of cardiac glycosides have been studied. Nineteen chronically instrumented beagle puppies underwent 2-week courses of parenteral digoxin in three dosage regimens: six received digoxin, 0.04 mg/kg/day; seven received 0.03 mg/kg/day; and 11 received 0.02 mg/kg/day. Mean serum concentrations were 3.2 ng/ml, 1.3 ng/ml, and 1.0 ng/ml, respectively. Significant electrophysiologic effects on sinus node function were produced only by the highest dose. Atrioventricular node conduction was significantly delayed among animals receiving both high and middle dosages. All three regimens significantly effected atrioventricular specialized conduction system functional refractory periods. Atropine decreased digoxin-induced effects on all measured parameters but totally eliminated the digoxin effect on the corrected sinus node recovery time.
A double-blind randomized trial of low-dose oral urea to prevent sickle cell crises.
Seventy-nine homozygous SS patients were randomly assigned to control or oral prophylactic urea treatment in a double-blind trial designed to determine whether prophylactic oral urea, in low doses, prevents sickle cell crises. The average follow-up time for these patients was 13.7 months and 33 patients were diagnosed as having one or more crises during the study. No statistically significant treatment differences were found in weight changes, bilirubin changes, or hemoglobin changes over the course of the study or in the distribution of time to first crises or time to second crisis. This study gives no evidence in favor of the hypothesis that prophylactic oral urea, in low doses, prolongs time to crisis.
Uptake of prolactin from cerebrospinal fluid in rat brain.
The fate of prolactin in the cerebrospinal fluid was studied by the use of fluorescein labelled prolactin. The distribution was compared to the immunocytochemical distribution of endogenous prolactin. High intensity fluorescence was found in the ependyma of the area postrema, rostral dorsolateral cerebral aqueduct close to the subcommissural organ, and in some cells of the floor of the cerebral aqueduct. This distribution was not seen when excess unlabelled prolactin was injected. The results suggest prolactin uptake from CSF at specific sites which correspond to sites of localization of immunoreactive prolactin.
Differential effects of antioxidants and indomethacin on compound 48/80 induced histamine release and Ca2+ uptake in rat mast cells.
The effect of nordihydroguaiaretic acid (NDGA), vitamin E, butylated hydroxytoluene (BHT) and indomethacin on histamine release and Ca2+ uptake in rat mast cells stimulated with compound 48/80 was studied. NDGA inhibited both the release of histamine and Ca2+ uptake in stimulated cells; however, there was no correlation between inhibition of Ca2+ uptake and the amount of histamine release. At a concentration of 5 microM, NDGA completely inhibited Ca2+ uptake, while histamine release was decreased by less than 50%. BHT (50 microM) inhibited both the Ca2+ uptake and histamine release. On the other hand, vitamin E (50 microM) inhibited histamine release by 70% without impairment in Ca2+ uptake. In the absence of the stimulus, vitamin E increased the cell-associated Ca2+; however, it had no effect on spontaneous release of histamine. Indomethacin (3 microM) inhibited Ca2+ uptake in stimulated cells by 50%, but did not affect the release of histamine. The results suggest that a part of Ca2+-influx may not be related to the coupled activation--secretion response and that lipid peroxidation through the lipoxygenase pathway may be involved in secretion of histamine from mast cells.
Teaching the mental status examination: comparison of three methods.
The authors compared videotape and lecture methods of teaching the mental status examination to a second-year medical school class. The results of each teaching method were evaluated by a multiple-choice examination and a feedback questionnaire and were compared with the results from teaching the mental status examination using simulated patients in a previous year's class. There was no clear difference in examination results for students exposed to different instructional methods. On the feedback questionnaire, students appeared to prefer instruction in whatever form it was given. The authors discuss the significance of these findings.
Deficient natural killer cell activity in a patient with Fanconi's anaemia and squamous cell carcinoma. Association with defect in interferon release.
A child with Fanconi's anaemia diagnosed at 7 years of age presented in adult life with lymphopenia, recurrent warts and Bowen's disease. The latter resulted in the development of multiple cutaneous squamous cell carcinomas which metastasized to the skeleton. Investigation of her immune function revealed selective defects in natural killer (NK) cell activity. Humoral immunity and several tests of cell-mediated responses were within normal or became normal after treatment with levamisole or transfer factor. Analysis of the defect in NK activity revealed that low levels could be induced in vitro by fibroblast interferon. Stimulation of blood lymphocytes from the patient with the interferon inducer poly (I)-poly (C) resulted in an increase in NK activity but incubation of her lymphocytes on tumour cells did not result in an increase in NK activity or the release of interferon. This contrasted with the marked increase in NK activity and interferon release observed when lymphocytes from normal controls were incubated on tumor cells. These findings suggested the absence of NK activity in this patient was secondary to a defect in interferon release from lymphocytes on exposure to tumour antigens. It is considered that these defects may have been an important predisposing factor in the development of malignancy in this patient and possibly other patients with Fanconi's anaemia.
New Orleans physician challenges hospital's policy on MD contracts.
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Bay Area hospital takes Madison Avenue approach.
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Move to deny hospital reimbursement for union organizing costs spreads.
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Systemic blastomycosis presenting with acute prostatic abscess.
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Temporal lobe epilepsy and schizophrenia: comparison of reaction time deficits.
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Systemic complications of rheumatoid arthritis.
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Cautionary tales from general practice. Authentic case histories from Australian general practice illustrating pitfalls in diagnosis and management. 'A real headache'.
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Shortage of MDs seen hampering research.
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