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Biomedical subjects

J D Stevens

Publications and source records attributed to J D Stevens.

50 records · Page 3Linked to original sources
PubMed1983

Propranolol-hydralazine combination in essential hypertension.

The efficacy of a propranolol-hydralazine combination tablet was compared with that of each of its two components in the twice-daily treatment of mild to moderate essential hypertension (diastolic blood pressure: 100 to 125 mmHg). After a three-week, single-blind, placebo period, a 9- to 18-week, single-blind, dose-finding phase with the combination was performed. The daily doses of propranolol/hydralazine were 40 mg/25 mg, 80 mg/25 mg, 80 mg/50 mg, 120 mg/50 mg, 160 mg/50 mg, and 160 mg/100 mg. Of 83 patients, 73 (88%) had decreases in diastolic blood pressure equal to or greater than 10 mmHg. Thirty-eight (46%) patients had a diastolic blood pressure equal to or less than 90 mmHg while taking 80 mg propranolol/50 mg hydralazine or less given BID. Mean systolic and diastolic pressures were reduced by 16.8 mmHg (10.9%) and 17.6 mmHg (16.7%), respectively (P less than 0.001). A ten-week, double-blind, parallel-treatment phase followed in which patients were randomly assigned to the combination tablet or to propranolol or hydralazine. There were significantly larger increases in mean systolic (P less than 0.01) and mean diastolic (P less than 0.03) blood pressure when the components were taken alone than with the combination from the mean of the last three weekly dose-finding visits to the mean of the last four biweekly parallel-treatment visits. The changes in systolic/diastolic blood pressures were: hydralazine (n = 30), 14.43/8.62 mmHg; propranolol (n = 24), 9.87/6.09 mmHg; and the combination (n = 27), 1.47/1.53 mmHg. During the parallel-treatment phase, the proportions of patients with new complaints were: hydralazine, 16/31 (52%); propranolol, 10/25 (40%); and the combination, 11/27 (41%). In the hydralazine group, three patients had cardiovascular events (severe tachycardia, mild palpitations, and skipped heart beats) and two patients had mild anxiety; no such occurrences were noted in the propranolol or combination group. The mean change (increase) in heart rate from the end of dose-finding to the end of the double-blind period was significantly larger for patients taking hydralazine than for patients taking propranolol or the combination. Mean changes for these groups were: hydralazine, 12.4 beats/min; propranolol, 2.9 beats/min; and the combination, 1.8 beats/min (P = 0.0001). This study found the combination of propranolol plus hydralazine to be safe and more effective than either component.

Adult↗
PubMed1982

Propranolol-hydrochlorothiazide combination in essential hypertension.

The effect of a propranolol-hydrochlorothiazide combination tablet was compared with the effects of its two components alone in the twice-daily treatment of mild to moderate essential hypertension (100 to 125 mmHg diastolic blood pressure). Propranolol alone or in combination was given at 80, 160, 240, or 320 mg/day; hydrochlorothiazide, at 50 mg/day. After a 3-week placebo period, a 12-week single-blind dose-finding test with the combination was held: 149/158 (94%) patients had decreases greater than or equal to 10 mmHg in diastolic blood pressure. Mean systolic and diastolic pressures were reduced by 26.6 mmHg 917%) and 19.2 mmHg (18.6%), respectively (P less than 0.001). A 10-week double-blind parallel treatment test followed, in which patients were assigned by random code to combination tablet, propranolol, or hydrochlorothiazide. There were significantly larger increases (P less than 0.05) in mean systolic or diastolic pressure with each component than with the combination from the end of dose-finding to each of the last four biweekly visits, to the mean of those four visits, and to the endpoint (last visit). The mean increases in pressure at the endpoint evaluation were (systolic/diastolic): combination (n = 47), 3.0/1.5 mmHg; propranolol (n = 51), 10.2/6.3 mmHg; hydrochlorothiazide (n = 52), 13.1/9.3 mmHg. During the double-blind period, no significant differences were demonstrated between the proportions of patients in each treatment group reporting new complaints. This study showed the combination to be as safe as, and more effective than, either component given at the same dose strength.

Adult↗
PubMed1975

Tumor-inhibiting properties of the neutral P-O-ethyl ester of adenosine 3':5'-monophosphate in correlation with its crystal and molecular structure.

The P-O-ethyl ester of cAMP has been synthesized, its inhibition of solid and ascites tumors studied, and its pattern of urinary excretion followed. Et-cAMP is more effective than cAMP against solid sarcoma 180 in mice and against Ehrlich ascites carcinoma cells in tissue culture. The urinary excretion pattern of injected E-t-cAMP suggests that about two-thirds of the injected dose (13 mumol per animal) is retained in the rat rather than being promptly excreted. Liver slice studies of the effect on glycogenolysis suggest that the Et-cAMP is converted to cAMP intracellularly. The compound crystallizes in space group P21 with one molecule per asymmetric unit. The base ring has the anti conformation. The ethyl group is endo to the base ring and is axial in the flattened chair-conformer six-membered ring formed by the 3'-5' O-P-O cyclization. In most other respects the structure of the compound is closely similar to the known structures of other cyclic nucleotides.

Animals↗
PubMedDate not supplied

Phototherapeutic smoothing as an adjunct to photorefractive keratectomy in porcine corneas.

PURPOSE: To study the smoothing effect of phototherapeutic keratectomy (PTK) using masking fluids as an adjunct to standard photorefractive keratectomy ablations. METHODS: Six fresh porcine corneas underwent -6.00, -10.00, and -15.00 D sphere ablations using the VISX Star excimer laser. Multizone treatments to a maximum 6.5 mm radially symmetrical bed were used with a fluence of 160 mJ/cm2. Three of the treatments were supplemented with a thin layer of balanced salt solution and 6 microm of full beam PTK. The corneas were examined by electron microscopy. RESULTS: Smoother treatment zones were apparent in corneas undergoing PTK following PRK. The effect was more marked at higher dioptric ablations. CONCLUSION: PTK may improve surface smoothness after PRK, especially for higher dioptric ablations.

Animals↗
PubMedDate not supplied

Surgical treatment of keratoconus at the turn of the 20th century.

PURPOSE: This paper reviews surgical modalities for treatment of keratoconus at the threshold of the 20th century. METHODS: All ophthalmic literature from 1895 until 1925 in English and German, available at the library of the Institute of Ophthalmology, London, United Kingdom, was studied with respect to this topic. RESULTS: Three thermal procedures were described; galvanocauterization with perforation, without perforation, and a non-contact application of heat to the corneal apex. Radial extension of a thermal burn to correct the minus cylinder represented a further modification. Excision of the conical area was suggested either as a lamellar dissection or as a full thickness trephination. Incision of the cone appeared to be less popular. In staged procedures, a combination of galvanocauterization, splitting of the cornea, conjunctival flap, and a subsequent optical iridectomy were applied. CONCLUSION: The treatment of keratoconus 100 years ago used refractive surgery to improve visual function by modifying corneal shape.

Cornea↗