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Biomedical subjects

R D Gordon

Publications and source records attributed to R D Gordon.

At least 145 records · Page 8Linked to original sources
PubMed1989

Extended preservation of human liver grafts with UW solution.

The fate of 185 cadaveric liver homografts preserved for four to 24 hours with University of Wisconsin (UW) solution was compared with that of 180 grafts preserved for three to 9 1/2 hours with conventional Euro-Collins solution. Although the average preservation time of the UW-preserved livers was almost twice as long as that of the Euro-Collins-preserved livers, the UW-preserved grafts survived at a higher rate; permitted equal patient survival; and had a lower rate of primary nonfunction, a reduced need for retransplantation, and a lower rate of hepatic artery thrombosis. There was no correlation between the time of preservation of UW-preserved grafts up to 24 hours and liver function abnormalities in the first postoperative week. In contrast, livers preserved with Euro-Collins solution for more than five hours had significantly increased perturbations of hepatic function tests. The potential revolutionary effect of the UW solution on liver transplantation is described herein.

Cause of Death↗
PubMed1989

Arterial mycotic aneurysm and rupture. A potentially fatal complication of pancreas transplantation in diabetes mellitus.

Mycotic aneurysm at the site of a Carrel patch arterial anastomosis occurred in four patients who had undergone whole pancreas transplantation 2.5 to 14.5 months previously. In all patients, the graft had been removed, leaving the Carrel patch on the iliac artery. The aneurysms ruptured into the intestine or the extraperitoneal space. The ruptures were sudden and life-threatening in three of four cases. This diagnosis must be suspected in patients with a history of pancreas transplantation in the immediate or distant past if they present with unexplained hypotension, cardiac arrest, or gastrointestinal tract bleeding.

Adult↗
PubMed1989

Mixture models for partially unclassified data: a case study of renal venous renin in hypertension.

In many applications of discriminant analysis in medicine, data of known origin which can be reasonably assumed to be a random sample from the entire class may not be available for each of the possible classes. In this paper we note how such situations can be handled by using finite mixture models to formulate the estimation problem. This approach is adopted to model the distribution of the renal venous renin ratio (RVRR) between left and right kidneys in patients with hypertension. This distribution is used in the formation of a probabilistic allocation rule as an aid in the diagnosis of renal artery stenosis, which is potentially curable by surgery.

Chi-Square Distribution↗
PubMed1989

Biliary tract complications in orthotopic adult liver transplantation.

In a series of orthotopic liver transplantations performed between April and August 1987 at the University of Pittsburgh, the monofilament absorbable suture polyglyconate was compared with a braided absorbable suture, polyglactin 910, for its biliary complication rate over a 6-month postoperative period. Complications that were suture-related (obstruction or leak from the anastomotic site) occurred in 1 of 21 transplantations in the polyglyconate group compared with 8 of 26 in the polyglactin 910 group (p = 0.02). Even though the patient sample was relatively small, it appears that the type of suture used for the biliary anastomosis directly correlates with the outcome. A larger patient trial could confirm these initial results.

Anastomosis, Surgical↗
PubMed1989

Reversal of hypersplenism following orthotopic liver transplantation.

The purpose of this study was to clarify the effect of orthotopic liver transplantation on hypersplenism. In a 1-year period from July 1, 1986 to June 30, 1987, 196 adult patients underwent 233 orthotopic liver transplantations. Of the 58 patients with hypersplenism who were analyzed in this study, hypersplenism was more commonly associated with postnecrotic cirrhosis than other kinds of liver disease (55.3% (47/85) vs. 14.5% (11/76); p less than 0.001). Postoperative platelet counts were statistically higher than preoperative values (p less than 0.05). The latest platelet counts were more than 100,000/mm3 in 53 patients (91.4%). Of the eight patients whose preoperative and postoperative spleen volumes could be compared, all showed the reduction in the spleen size (p less than 0.02). We conclude that orthotopic liver transplantation, which is a radical surgical procedure for portal hypertension, reverses hypersplenism.

Adult↗
PubMed1989

Reduced adrenal secretory mass after unilateral adrenalectomy for aldosterone-producing adenoma may explain unexpected incidence of hypotension.

In a prospective study of 37 patients who had unilateral adrenalectomy for an aldosterone-producing adenoma, five of 33 (15%) were symptomatically hypotensive after at least 1 year, and eight of 29 (28%) who were observed 3, 6, 12, 18 and 24 months after the operation showed 2-year blood pressures below the fifth percentile for age- and sex-matched controls. Postoperatively, plasma aldosterone was lower, and plasma renin activity higher than in controls, these differences being more marked in the hypotensive group. Pre-operatively elevated atrial natriuretic factor fell to levels lower than in controls. These serial changes in volume-regulatory hormones are consistent with chronic hypovolaemia, due to relative hypoaldosteronism. Plasma cortisol was lower 6 months after the operation and plasma adrenaline levels fell by half. A reduced adrenocortical (aldosterone and cortisol) and adrenomedullary (adrenaline) secretory mass may play a role in the hypotension observed after unilateral adrenalectomy.

Adenoma↗
PubMed1989

A controlled clinical trial on the cardiovascular effects of single doses of pseudoephedrine in hypertensive patients.

Twenty hypertensive patients received single oral doses of pseudoephedrine 60 mg or placebo in a double-blind, randomised, crossover trial. Systolic, diastolic, mean arterial blood pressure, and heart rate were measured at 5 min intervals for 30 min prior to and 210 min after the administration of pseudoephedrine or placebo. Statistically significant differences between the two treatments were observed with changes in systolic blood pressure (P less than 0.03) and heart rate (P less than 0.01) but not in diastolic (P greater than 0.03) and mean arterial blood pressure (P greater than 0.1). Minor differences in the number of reported side effects between the two treatments were not statistically significant.

Adult↗
PubMed1989

Levels of atrial natriuretic peptide are not always consistent with atrial pressure: is there alternative regulation as evidenced in Gordon's and Bartter's syndromes?

1. In Bartter's syndrome, atrial pressures were low, consistent with volume contraction, while atrial natriuretic peptide (ANP) levels were unexpectedly elevated. Infusion of normal saline increased both right atrial pressure (RAP) and ANP levels, while administration of prostaglandin inhibitors raised RAP, probably due to volume expansion, but ANP levels fell paradoxically. 2. In Gordon's syndrome, atrial pressures were unexpectedly low or normal despite volume expansion, while ANP levels were normal. Pressor infusions of angiotensin II either raised right and left atrial pressures (LAP) without increasing ANP, or increased ANP without increasing atrial pressures. 3. In these two syndromes, atrial pressures and ANP levels were poorly correlated, leading to the proposal that other regulators of ANP may be important.

Adenoma↗
PubMed1989

Phaeochromocytomas secreting adrenaline but not noradrenaline do not cause hypertension and require precise adrenaline measurement for diagnosis.

1. Urinary noradrenaline (NA) and adrenaline (ADR) determinations are a more sensitive index than plasma measurements for the diagnosis of phaeochromocytoma (phaeo). 2. Even though urinary NA excretion serve as a sufficient single diagnostic test for the majority of phaeos, it is necessary to measure urinary ADR excretion if ADR-only secreting phaeos are not to be missed, particularly in patients with multiple endocrine neoplasia (MEN) syndrome. 3. The clonidine suppression test confirmed all tumour diagnoses, and in this series was not responsible for any false negative or false positive results.

Adolescent↗
PubMed1989

Unexpected incidence of low blood pressure 2 years after unilateral adrenalectomy for primary aldosteronism.

1. Serial observations of blood pressure after unilateral adrenalectomy for aldosterone-producing adenoma revealed an incidence of hypotension (systolic BP less than fifth percentile for age- and sex-matched normal population) of 27% at 2 years, more than 5 times that predicted. 2. Serial observations of volume regulatory hormones showed significantly raised mean levels of plasma renin activity consistent with hypovolaemia. Significantly reduced mean aldosterone levels despite significantly raised mean plasma renin activity levels may reflect reduced responsiveness of the remaining adrenal. 3. Reduction of significantly elevated preoperative ANP levels to significantly reduced levels postoperatively is also in keeping with postoperative hypovolaemia. 4. A 50% reduction in plasma adrenaline after unilateral adrenalectomy might contribute to reduced noradrenergic activity (prejunctional beta-receptor) and reduced blood pressure, but plasma noradrenaline did not fall significantly postoperatively. 5. Postoperative levels of renin, aldosterone, adrenaline and noradrenaline were not significantly different between those who did, and those who did not, become hypotensive.

Adenoma↗
PubMed1989

Effects of altitude on atrial natriuretic peptide: the Bicentennial Mount Everest Expedition.

1. Overnight recumbent atrial natriuretic peptide levels were significantly elevated in all ten subjects of the Australian Bicentennial Mount Everest Expedition during the first week at 5400 m, during acclimatization. 2. Twenty-four hour urine volume and urine sodium increased markedly at altitude. 3. Plasma renin activity and plasma aldosterone levels decreased significantly at altitude. 4. No significant changes in plasma cortisol, plasma sodium or potassium, body temperature, systolic or diastolic blood pressure or heart rate were observed. 5. Although it was impossible to control or measure salt and water intake during the study, results suggest that atrial natriuretic peptide may be important in the reduction in renin and aldosterone levels and in the diuresis and natriuresis necessary to adapt to hypoxia at altitude.

Adult↗
PubMed1989

Renal artery duplex ultrasonography: a reliable new screening test for functionally significant renal artery stenosis.

1. Renal artery duplex ultrasonography (RADU) has recently become available as a rapid, relatively inexpensive, non-invasive screening test for renal artery stenosis causing renovascular hypertension. 2. We compared the sensitivity of RADU with that of computerized nuclear renography (CNR) in 16 patients with renovascular hypertension. All had lateralizing renal venous renin ratio (RVRR) studies, 15 had renal artery stenosis (RAS) on angiography and one had unilateral chronic parenchymal renal disease (CPRD). 3. We found RADU to be at least as reliable as CNR with sensitivities of 100% and 93.7%, respectively. Neither RADU nor CNR was successful (sensitivity 25% and 0%, respectively) in detecting minor, functionally insignificant contralateral renal artery stenosis in four patients, two of whom had multiple small renal arteries--a recognized difficulty in the use of RADU. 4. After successful (RVRR became negative) therapeutic intervention in two patients with RAS (dilatation one, surgery one), RADU changed from positive to negative and may therefore be a useful alternative to repeat angiography in this setting. 5. Performed in conjunction with renal parenchymal B mode ultrasound, RADU correctly identified the presence of CPRD in one patient.

Humans↗
PubMed1989

Liver transplantation for alcoholic liver disease: a consideration of reasons for and against.

Orthotopic liver transplantation is a clinical procedure that has been accepted widely as the treatment of choice for individuals with advanced chronic liver disease. As such, its application to the important clinical problem of alcoholic liver disease is inevitable. The arguments for and against liver transplantation for individuals with advanced alcoholic liver disease are presented.

Humans↗
PubMed1989

Infusions of adrenaline stimulate noradrenergic transmission in man, but adrenaline is not released later as a co-transmitter.

A pre-junctional beta-adrenoceptor facilitating noradrenergic transmission may be affected by elevations in circulating adrenaline, and represent a mechanism whereby mental stress might predispose to hypertension. The proposition that circulating adrenaline can be taken up into noradrenergic nerve terminals and later co-released with noradrenaline in response to an appropriate stimulus was examined. The effects of upright posture, before and after a 60 min adrenaline infusion were as follows: (1) Changes in heart rate and diastolic blood pressure were not augmented. (2) Plasma noradrenaline response was not increased. (3) Plasma adrenaline basally and in response to posture remained low. (4) Radiolabelled adrenaline disappeared from the circulation on cessation of infusion, and did not reappear in response to posture or isometric exercise. While adrenaline infusion again increased noradrenaline, we found no evidence of subsequent adrenaline release in response to noradrenergic stimulation. These studies do not exclude adrenaline uptake and re-release in amounts sufficient to stimulate the prejunctional beta-adrenoceptor, but insufficient to reach the circulation after local metabolism.

Adult↗