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Biomedical subjects

G M Collins

Publications and source records attributed to G M Collins.

At least 55 records · Page 3Linked to original sources
PubMed1984

The value of magnesium in flush solutions for human cadaveric kidney preservation.

A cooperative clinical trial was conducted among 5 transplant centers in the western United States to determine the value of magnesium sulfate in intracellular electrolyte flush solutions for hypothermic, human kidney storage. Kidneys from alternate donors were flushed with either magnesium-free Euro-Collins' solution or magnesium-containing Collins' 2 solution. Donor and recipient ages, and mean preservation times were not significantly different between the 2 groups. There was a significantly lower dialysis requirement during the first week in the magnesium-containing Collins 2 group (33 per cent) versus the Euro-Collins group (54 per cent). Function rates and serum creatinine nadirs at 1 month were not significantly different. The beneficial effect of magnesium sulfate was more evident when preservation times exceeded 24 hours.

Adult↗
PubMed1984

Improved function of perfused rabbit kidneys by prevention of oxidative injury.

This study explored the effect of adding small amounts of the reducing agents ascorbic acid and glutathione to a Ringer's-albumin perfusate used for 24-hr hypothermic perfusion of rabbit kidneys. Maintenance of function during preservation was evaluated with a shunt perfusion model and by measuring the ability of cortical slices to restore normal K/Na ratios after incubation in a electrolyte medium. When placed in contact with the unmodified perfusate, an electrode of pyrolytic carbon registered a potential of +190 mV relative to the silver-silver chloride couple. This reading fell rapidly by 100-125 mv when kidneys were placed on the circuit. The mean creatinine clearance after 24-hr perfusion was significantly improved from 162 +/- 56 ml/hr in controls to 284 +/- 92 ml/hr when the potential indicated by this electrode was preadjusted to 43-54 mv with reducing agents, and to 237 +/- 62 ml/hr when this adjustment was made after 2 hr. These creatinine clearances were similar to those of kidneys stored on ice for only 1 hr. These findings indicate minimal injury occurred in the chemically reduced groups and emphasize the importance of preventing oxidative damage to kidneys during hypothermic organ perfusion. The time course of the changes in potential registered by this electrode was consistent with our previous finding that much of the damage to perfused kidneys occurs very early in the course of perfusion. The tissue slice studies showed no detectable damage to the renal parenchyma of the kidneys in the control group despite diminished creatinine clearance. This suggests that the site of oxidation injury is the vascular compartment.

Animals↗
PubMed1983

Life expectancy and late stroke following carotid endarterectomy.

A review of the UCSD experience with 456 consecutive carotid endarterectomy procedures confirms the acceptably low operative mortality and morbidity associated with this operation. Immediate complications were not different when routine or selective shunting was performed, but the patients with a low internal carotid artery back pressure had higher operative complication rates. The coexistence of atherosclerosis in other parts of the body severe-enough to warrant surgery for them was not associated with either higher early or late carotid surgery complication rates. Following both coronary bypass and carotid procedures, the late mortality was decreased, and the late incidence of stroke was particularly low in comparison to the remainder of the patient group. Late follow-up emphasized the high continuing attrition rate from all causes in these patients. Late strokes continued to occur, particularly in patients with prior strokes and severe preoperative bilateral carotid disease. The late course of patients with posterior circulation transient ischemic attacks treated by carotid endarterectomy was quite similar to that of patients treated for anterior circulation transient ischemia attacks (TIAs). Newer postoperative screening procedures may decrease the incidence of late postoperative stroke by identifying recurrent carotid stenosis while it is still in the asymptomatic stage.

Aged↗
PubMed1982

Transplant renal artery thrombosis. Revascularization after 51/2 hours of ischemia.

Restoration of blood flow to a transplanted kidney following renal artery thrombosis should provide a good model for determining the tolerance of the human kidney to normothermic ischemia. Two cases were seen in which function returned after two and 51/2 hours of occlusion. These, together with two other similar cases reported previously, suggest that attempted revascularization is worthwhile even after several hours of ischemia.

Acute Disease↗
PubMed1982

Is carotid endarterectomy beneficial in prevention of recurrent stroke?

Of 456 consecutive carotid endarterectomies performed at the University of California, San Diego, 127 were in patients who had sustained a previous completed stroke and had recovered with minimal but permanent neurologic deficits (PNDs). Operative mortality for the entire series was 0.9%, but it was 3.1% for the stroke group. A postoperative PND was observed in 2.1% of patients without neurologic deficits but occurred in 3.9% of the patients after stroke. A 97% one-to-ten-year follow-up was obtained. The total early and late serious morbidity and mortality in this surgically treated series of patients after stroke was 24% at five years. We conclude that carotid endarterectomy for the prevention of recurrent stroke carries a high risk and may not be superior to nonoperative treatment.

Adult↗
PubMed1982

Should aortography be used routinely in the elective management of abdominal aortic aneurysm?

Until recently aortography was performed routinely for elective abdominal aortic aneurysm at our institution. A death resulting from this procedure prompted us to evaluate this policy by a retrospective study of 105 elective aneurysm patients. These studies identified 21 renal artery stenoses, 2 renal artery aneurysms, 2 cases of multiple renal arteries, 8 celiac stenoses, 6 superior mesenteric artery stenoses or occlusions, and a number of peripheral occlusive processes and associated iliac aneurysms. However, the impact of these findings on surgical management was limited to six renal artery reconstructions: one for reimplantation of a renal artery arising from the aneurysm, one for serious hypertension, and four in normotensive patients with severe arterial stenosis. No celiac or mesenteric reconstructions were undertaken, and no visceral complications ensured. In only one patient, the one with renal artery reimplantation, was the angiographic information unsuspected and significant for operative management. This did not appear to justify the risk and expense involved in routine preoperative aortography.

Aorta, Abdominal↗
PubMed1981

Nonaneurysmal suppurative aortitis.

Two patients had nonaneurysmal suppurative aortitis. In one, the aortic ruptured and the patient died. The second patient had Salmonella sepsis and occlusion of the infrarenal aorta. He was treated with aortic resection and extra-anatomic bypass, but died 20 months later of an unrelated illness. Patients with Salmonella sepsis who are over 50 years of age or who are suspected of having aortic atherosclerosis should be evaluated carefully for aortitis since rupture or aneurysm formation is associated with a dismal prognosis.

Aged↗
PubMed1980

Studies of the ideal [H+] for perfusional preservation.

The neutral point of water, being a function of its dissociation constant, is temperature dependent. This is also true of protein-buffered solutions such as perfusates. In organ preservation these facts have been long ignored and, as a result, perfusions have been carried out in a relatively acidotic environment. These studies evaluated the effects of correcting the pH partially or completely for the level of hypothermia involved in perfusional preservation. The findings both in rabbits and dogs were that a pH of 7.4 (measured at 7 C) is dangerously close to the pH below which there is rapid deterioration of function. On the other hand, perfusate pHs up to 7.75 in dogs and 8.25 in rabbits were tolerated at no detriment. As a result, the recommendation is made to carry out hypothermic organ perfusion at a pH well above 7.4; 7.60 or 7.65 seems reasonable.

Animals↗
PubMed1979

Pharmacological protection of rabbit kidneys from normothermic ischemia.

This study investigated the influence of the administration of pharmacological agents on the recovery of rabbit kidneys from the effects of 1 hr of situ normothermic ischemia, utilizing acute and chronic models. The agents tested included the diuretics mannitol and furosemide, the vasoactive agents phenoxybenzamine, propranolol, and dopamine, and the membrane stabilizers chlorpromazine and methylprednisolone. A beneficial effect was detected only with the diuretic agents and propranolol when given prior to the ischemic insult.

Animals↗
PubMed1978

Transplant renal artery stenosis occurring in both recipients from a single donor.

Stenosis of the renal artery is increasingly being recognized as a cause of hypertension and renal failure after kidney transplantation. To our knowledge, this is the first report of an almost simultaneous occurrence of this complication in both recipients of kidneys from a single donor. In both cases, surgical correction led to improved renal function and amelioration of the hypertension.

Adult↗