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Biomedical subjects

J R Graham

Publications and source records attributed to J R Graham.

At least 91 records · Page 5Linked to original sources
PubMed1982

Long-acting and short-acting diuretics in mild essential hypertension.

A randomised, placebo-controlled, double-blind crossover study was conducted in 14 patients with mild essential hypertension comparing different regimens of administration of the "short-acting" diuretic, chlorothiazide and the "long-acting" diuretic, chlorthalidone. There were 6 randomised treatment phases each of 5 weeks duration. For blood pressure recorded both at the Clinic and at home the most prominent effects were seen with standing blood pressure, for which significant reductions of mean blood pressure compared to the placebo phase were observed with chlorthalidone 25 mg once daily (-5 +/- 1 (SE) mm Hg - p less than 0.05), chlorthalidone 50 mg once daily (-7 +/- 1 mm Hg - p less than 0.01) and chlorothiazide 500 mg twice daily (-4 +/- 1 mm Hg - p less than 0.05). Blood pressure reductions with chlorothiazide 500 mg once daily and 1000 mg once daily were not significant. About half of the patients completing the trial could be described as "non-responders". The observed biochemical changes (reduced plasma potassium and chloride concentrations and increased plasma bicarbonate and urate concentrations) were most marked in the phases with the most prominent blood pressure effects. The result support the suggestion that a sustained diuretic effect is desirable when diuretics are used in the treatment of hypertension. This can be obtained by selection of the appropriate dosage regimen for a particular diuretic, such as once daily administration for "long-acting" and twice daily for "short-acting" thiazide-type diuretics.

Adult↗
PubMed1981

Comparison of indapamide with thiazide diuretics in patients with essential hypertension.

The effect of the new diuretic antihypertensive drug, indapamide (2.5 mg a day), was compared with the effect of thiazide diuretics in 24 patients with hypertension (seven of whom were receiving a diuretic alone, six were taking a beta-blocker plus a diuretic, and 11 received other combinations of drugs, including a diuretic in all cases). The randomized crossover study with two six-week phases indicated that indapamide is an effective hypotensive agent with potency similar to that of the thiazide diuretics in lowering the blood pressure and in increasing the excretion of potassium.

Benzothiadiazines↗
PubMed1981

Peridural meperidine in humans: analgesic response, pharmacokinetics, and transmission into CSF.

Effective analgesia resulted from the injection of peridural meperidine in two groups of cancer patients, eight with postoperative pain and eight with intractable pain. Peridural meperidine HCl, 100 mg (n = 8), in 10 ml saline administered to patients following surgery was followed by a median duration of analgesia of 6 hours (range 4-20 hours) over periods ranging from 1-4 days. Peridural meperidine HCl, 30-100 mg (n = 8), in 10 ml saline administered to patients with intractable pain gave a median duration of analgesia of 8 hours (range 4-20 hours) over periods ranging from 1-9 days. There was no obvious tendency towards tolerance. In all patients, the onset of analgesia was within 5 min and was complete within 30 min. This analgesia paralleled the rise in CSF meperidine concentrations following peridural administration. Systemic absorption of peridurally administered meperidine occurred with a half-life of 15-30 min and produced blood concentrations high enough to contribute to analgesia after approximately 20 min in the majority of patients. There was no objective evidence in any neurological change nor sympathetic blockade after peridural meperidine. From this evidence the dorsal horn of the spinal cord may be the major site of action as distinct from the axonal blockade produced by local anesthetics, indicating 'selective' spinal analgesia.

Adult↗
PubMed1980

On the origins of 718 nm fluorescence from Porphyridium cruentum at 77 K.

Emission spectra and transient behavior of fluorescence in Porphyridium cruentum have been studied in search of the pathway of excitation energy from the phycobilisome to Photosystem I (PS I) of photosynthesis. For activating light at 436 nm, absorbed almost entirely by chlorophyll, fluorescence is dominated by the 718 nm band generally attributed to chlorophyll of PS I. Activating light at 550 nm, absorbed mostly by the phycobilisome, gives rise to the distinctive fluorescence band of PS II chlorophyll at 696 nm but also gives a large component at 718 nm. Analysis depends critically upon the source of emission at 718 nm under 550 nm activation: does it arise from PS I or PS IIC0 Ley and Butler (Ley, A.C. and Butler, W.L. (1976) Proc. Natl. Acad. Sci. U.S.A. 73, 3956-3960) have proposed that the 718 nm arises mostly from PS I, to which it is transferred by spillover from PS II. We suggest a different proposition: that under 550 nm activation most of the 718 emission arises from PS II. Analysis shows that this proposition provides an alternative explanation. Using the small change in fluorescence yield observed under 436 nm activation as a monitor of excitation in PS I, we provide evidence that under 550 activation most of the 718 nm fluorescence arises from PS II.

Darkness↗
PubMed1980

Comparison of labetalol, hydrallazine, and propranolol in the therapy of moderate hypertension.

The efficacy of labetalol, an alpha and beta adrenoceptor blocking drug, has been compared with that of placebo, of propranolol alone, of hydrallazine alone, and of hydrallazine plus propranolol in combination in a randomized double-blind, fixed-dose crossover trial. Labetalol (300 mg twice a day) was equally effective with propranolol (80 mg twice a day), and more effective than hydrallazine (50 mg twice a day) alone. The effect of labetalol was comparable with that of hydrallazine plus propranolol when the patient was standing, but less potent with the patient in the supine position. Side effects were few.

Antihypertensive Agents↗
PubMed1980

Spontaneous pigment mutants of Anacystis nidulans selected by growth under far-red light.

Under far-red (greater than 650 nm) illumination Anacystis nidulans grows poorly and develops a low chlorophyll content. During continued culture over many generations there are increases in growth rate and in the chlorophyll/phycocyanin ratio, usually occurring in concomitant and stepwise fashion. From such selection cultures six clones have been established which differ from the parent in pigment content and show improved growth rate in far-red light. From the evidence at hand the six clones are presumed to be spontaneous mutants selected under the photosynthetically restrictive condition of far-red illumination.

Chlorophyll↗