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Biomedical subjects

J W Hollifield

Publications and source records attributed to J W Hollifield.

At least 37 records · Page 2Linked to original sources
PubMed1981

Papilledema in two patients with acromegaly and intrasellar pituitary tumors.

Two patients had bilateral papilledema complicating acromegaly. Both patients had enlarged blind spots, but otherwise visual fields were normal. Suprasellar extension of the pituitary tumors was diligently sought with the use of visual field examination, pneumoencephalography, internal carotid arteriography, and computed axial tomography, and tumor extension did not exist. Transphenoidal and transethmoidal routes were used to perform partial hypophysectomies in these patients. The procedure was completely successful in one patient and partially successful in the other patient. After hypophysectomy, papilledema resolved in both patients. This beneficial effect may be the result of anatomical changes, the reduction in growth hormone levels, or both. These observations suggest that the acromegaly may be different from papilledema that occurs secondary to suprasellar expansion of pituitary tumors.

Acromegaly↗
PubMed1980

Effect of some organic acids in the incubation step on plasma renin activity.

The organic acids potassium hydrogen phthalate (KHphthalate), maleic, critic, acetic, formic, and oxalic were used to adjust the pH of plasma to 5.6 +/- 0.2 in the incubation step of the procedure for the determination of plasma renin activity (PRA). When compared to the PRA determined after pH adjustment with hydrochloric acid (HCl), it was found that KHphthalate and maleic acid produced a statistically significant increase in PRA. In comparison to HCl, KHphthalate and maleic acid showed a mean percent difference of 61% and 27% respectively for a one hour incubation; and, 57% and 34% respectively for a three hour incubation.

Acetates↗
PubMed1980

[Surgical treatment of renovascular hypertension: results of operation in 400 patients with renal artery stenosis (author's transl)].

A report is given on patients treated surgically for renal artery stenosis (RAS) and renovascular hypertension. High-quality arteriograms, as well as renal vein (RVR) determination and split-function studies (SFS) are the most important preoperative diagnostic procedures. Since only 40% of the patients with renal artery stenosis have renovascular hypertension, the value of RVR and SFS for diagnosis, indication and prognosis in surgical cases is stressed. Unilateral RAS patients show a 50% cure rate with regard to arteriosclerosis (AS) and 74% in fibromuscular displasia (FD). Improvement following surgery was recorded in 92% and 96% of cases, respectively. Bilateral reconstructions are preferably done as staged procedures. Simultaneous repair results in a higher postoperative thrombosis rate, as well as being a significant risk to both kidneys; only 50% of patients really do need surgical treatment of the contralateral kidney. Patients older than 50 years became normotensive in 36% of cases, 86% showed improvement and 13% no benefit from operation; the mortality rate was 1.3% in patients over 50. Cases with a severe reduction in kidney function (less than 30 ml/min/kidney creatinine clearance) showed a significant increase in creatinine clearance with a 90% improvement in and 36% cure of hypertension, after reconstruction. 50% of totally occluded renal arteries could be revascularized via an appropriate distal vessel; the cure rate in this group was 55%. A higher incidence of renovascular hypertension is seen in patients under the age of 20. 68% of this group became normotensive, whilst only 8% did not show any benefit from surgery. Combined diagnostic procedures to evaluate morphology and functional status of the kidney, as well as the indications for and prognosis of surgery are emphasized; a more refined technical approach to RAS revascularisation is described.

Adolescent↗
PubMed1979

Prognostic factors in adrenal cortical tumors. A mathematical analysis of clinical and morphologic data.

Forty-one patients with adrenal cortical tumors were evaluated retrospectively for the presence of histologic and non-histologic features associated with malignant behavior. The patients who survived operation were followed at least five years. The association of these features with subsequent metastasis was examined by both parametric and nonparametric statistical methods. Twelve criteria were statistically significant in predicting subsequent metastasis. The most significant of these were: clinical evidence of weight loss, broad fibrous bands traversing the tumor, a diffuse growth pattern, vascular invasion, tumor cell necrosis, and tumor mass. The tendency toward metastasis for each tumor was expressed in indices that correlated well with diagnoses made by conventional histologic means, but were more accurate in predicting subsequent clinical behavior than nonquantitative methods of evaluation.

Adolescent↗
PubMed1979

Reduction of plasma renin activity by inhibition of the fatty acid cyclooxygenase in human subjects: independence of sodium retention.

We carried out the present studies to determine whether the suppression of plasma renin activity (PRA) that follows inhibition of prostaglandin (PG) synthesis can be dissociated from the sodium-retaining effects of these drugs. In an initial investigation we studied the effect of indomethacin on PRA in normal subjects in balance on a 10 mM Na+ diet to prevent Na+ retention. Under these experimental conditions indomethacin did not lower PRA even though the fatty acid cyclooxygenase was inhibited, as indicated by a greater than 70% reduction in the major urinary metabolite of prostaglandin E (PGE-M). Sodium depletion leads to enhanced sympathetic activity. We therefore studied the effect of indomethacin on a group of subjects in 10 mM Na+ balance in whom the effect of increased beta-sympathetic activity was blocked by the administration of propranolol. In this group, indomethacin caused 65% suppression of PGE-M and had no effect on Na+ balance, but reversibly reduced PRA in the supine and upright positions by 84% and 70%, respectively. In normal subjects in 10 mM Na+ balance, the isoproterenol-induced increase in PRA also was unaffected by indomethacin. These data establish that inhibition of the cyclooxygenase can result in a reduction of PRA that is independent of changes in Na+ balance or beta-sympathetic tone.

Adult↗
PubMed1979

Primary aldosteronism: diagnosis, localization, and treatment.

New diagnostic techniques have enhanced the detection of primary aldosteronism. However, the response of blood pressure after operation in unilateral and bilateral adrenal disease is different. We have compared four localizing techniques--adrenal venography, adrenal isotopic scanning, a modified adrenal venous sampling for steroid measurements, and the anomalous postural decrease in plasma aldosterone concentration--in 51 patients with primary aldosteronism, all of whom had undergone operative confirmation. Adrenalectomy resulted in normal blood pressure in 59%, improvement in 25%, and no change in 16%. Correct localization of the lesion was obtained in 47% by the adrenal isotopic scan, in 66% by adrenal venography, and in 91% by the modified adrenal venous hormone technique despite four false-positives. Of the 26 patients with an anomalous postural decrease in plasma aldosterone, 88% had a unilateral lesion.

Adenoma↗
PubMed1979

Revascularization of the poorly functioning kidney.

The effect of renal vascularization on renal function in kidneys with poor preoperative excretory function is summarized in this report. Twenty-five patients with kidneys having preoperative creatinine clearance of less than 30 ml/min, as determined during split renal function studies (SRFS), which were revascularized for treatment of secondary renovascular hypertension and then were reevaluated by repeat SRFS form the basis of this report. There were 13 male and 12 female patients. The type of renal artery lesion was atherosclerotic in 21 patients and fibromuscular dysplastic in four patients. Eight individuals had total renal artery occlusion. Significant contralateral renal artery disease was present in 15 patients (60%). Preoperative creatinine clearances in the affected kidneys ranged from 0.27 ml/min (mean, 16 +/- 9 ml/min). after operation, creatinine clearances ranged from 0 to 72 ml/min (mean, 32 +/- 16 ml/mn). Fifteen of the 16 kidneys with preoperative creatinine clearances less than 20 ml/min had improvement in renal function following revascularization (P less than 0.01). Improvement (60%) or cure (36%) in hypertension followed revascularization in 24 of the 25 patients. The most dependable predictor of successful management of both hypertension and retrieval of renal function in these patients was the arteriographic demonstration of a patent distal vessel without evidence of severe intrarenal stenoses. These results support an aggressive attitude toward the use of revascularization in the operative treatment of such patients with renovascular hypertension, even when the residual excretory function is minimal or absent.

Adult↗
PubMed1978

Effects of caffeine on plasma renin activity, catecholamines and blood pressure.

Using a double-blind, randomized, cross-over protocol, we studied the effect of a single dose of oral caffeine on plasma renin activity, catecholamines and cardiovascular control in nine healthy, young, non-coffee drinkers maintained in sodium balance throughout the study period. Caffeine (250 mg) or placebo was administered in a methylxanthine-free beverage to overnight-fasted supine subjects who had had no coffee, tea or cola in the previous three weeks. Caffeine increased plasma renin activity by 57 per cent, plasma norepinephrine by 75 per cent and plasma epinephrine by 207 per cent. Urinary normetanephrine and metanephrine were increased 52 per cent and 100 per cent respectively. Mean blood pressure rose 14/10 mm Hg one hour after caffeine ingestion. There was a slight fall and then a rise in heart rate. Plasma caffeine levels were usually maximal one hour after ingestion but there was considerable individual variation. A 20 per cent increase in respiratory rate correlated well with plasma caffeine levels. Under the conditions of study caffeine was a potent stimulator of plasma renin activity and adrenomedullary secretion. Whether habitual ingestion has similar effects remains to be determined.

Administration, Oral↗