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Biomedical subjects

T D Rohde

Publications and source records attributed to T D Rohde.

At least 37 records · Page 2Linked to original sources

A double balloon catheter technique for alloxan diabetogenesis in the dog.

Venous injection of alloxan monohydrate is a standard method to produce a canine model of diabetes. Others have reported mortalities greater than 45 per cent and yields of diabetic dogs of less than 36 per cent with this technique. In this study, a new method for alloxan diabetogenesis is reported upon: alloxan monohydrate is injected intravenously with protection of the renal arteries at the time of injection by a 7F, triple lumen double balloon catheter placed in the abdominal aorta. The balloons are inflated under fluoroscopic control to occlude the renal arteries at the time of injection. Forty-three age-matched beagle dogs were initially injected with 60 milligrams per kilogram of alloxan monohydrate: 26 or 61 per cent became diabetic-defined as persistently doubled fasting serum glucose and glucosuria; ten failed to become diabetic, 23 per cent, and seven died, 16 per cent. The ten initial failures were reinjected with 65 milligrams per kilogram of alloxan monohydrate: six or 60 per cent then became diabetic, three were persistent failures, 30 per cent, and one dog died, 10 per cent. Thus, the over-all yield of diabetic dogs was 74 per cent, with an 18 per cent mortality. Minimal renal damage occurred, as evidenced by creatinine clearance, blood urea nitrogen and renal biopsy studies. These results suggest a significantly improved method--a twofold improvement over standard success rates with a twofold less mortality--of producing diabetic dogs by alloxan injection.

Alloxan↗

Intraarterial infusion chemotherapy for hepatic carcinoma using a totally implantable infusion pump.

Intraarterial infusion chemotherapy has several theoretical advantage over conventional therapy for the treatment of unresectable malignancies. However, the catheter problems and patient restriction to the hospital associated with its use have resulted in infrequent application and a notable lack of progress in this field of oncology. This paper describes the use of a totally implantable, percutaneously refillable infusion pump in 5 patients with primary or metastatic carcinoma of the liver. The infusion cannulae were placed into the hepatic arteries under direct vision at laparotomy, and the pumps were placed in subcutaneous pockets. Four patients received infusions of 5-fluorodeoxyuridine at rates of 0.2-0.5 mg/kg/day for periods of three to 29 weeks; the pump in the fifth patient was defective and was removed. The implanted pumps were well tolerated in these subjects, who received chemotherapy as outpatients; the only adverse effects noted were related to FUDR toxicity. This implantable infusion pump appears to be a practical means of delivering long-term intraarterial infusion chemotherapy to outpatients.

Antineoplastic Agents↗

Long-term, continuous intravenous heparin administration by an implantable infusion pump in ambulatory patients with recurrent venous thrombosis.

We studied the effect of long-term intravenous heparin infusion, delivered by a self-recycling, totally implantable infusion pump developed in our laboratory, in 21 patients with recurrent thromboembolic disease. Continuous infusions were maintained in these patients from 1 to 36 months, during which pumps were refilled by percutaneous needle injection at 4- to 8-week intervals. We maintained plasma heparin levels between 0.1 and 0.3 U/ml plasma. This regimen prevented thromboembolic phenomena in all except one patient, who apparently is refractory to heparin as well as oral anticoagulant drug therapy. Marked reduction of pain and improvement of mobility were reported by several patients with vena cava ligature syndrome. No spontaneous hemorrhagic complications occurred; however, several episodes of pump site hemorrhage were associated with pump refills. Bone mineral densities measured in eight subjects after 1 year of heparin infusion [1.00 +/- 0.06 (SE) gm/cm] were not significantly (P = 0.5) different from baseline values (0.98 +/- 0.08 gm/cm); however, osteoporosis did occur in one subject. Serum calcium, phosphorus, alkaline phosphatase, cholesterol, and triglycerides also remained unchanged in these subjects. These data suggest that continuous long-term heparin infusion is a viable therapeutic alternative in subjects with refractory thromboembolic disease.

Adult↗

The implantable infusion pump: a new concept in drug delivery.

Several of our most useful drugs cannot be administered orally. This paper is a summary of our work with a new drug delivery system: a totally implantable, continuous infusion pump, with a self-contained inexhaustible power source. Currently, after bench tests and animal experimentation, we have initiated clinical series utilizing this device to treat individuals with refractory thromboembolic conditions by intravenous heparin, and patients with localized solid tumors by intra-arterial chemotherapy. The use of this device for the infusion of insulin in the management of diabetes mellitus is yet in the laboratory stage of development. In addition to improving dy-today diabetic control and obviating the need for daily insulin injections, this pump offers an ideal opportunity to test whether optimal blood glucose control can significantly prevent or delay the onset of the crippling vascular complications of diabetes. The potential uses of this device, in many fields, are myriad.

Adult↗

Control of blood glucose in experimental diabetes by means of a totally implantable insulin infusion device.

Near-normal glucose tolerance tests in diabetic dogs were obtained during basal rate insulin infusions in restrained animals by use of extracorporeal infusion pumps and in conscious, unrestrained animals by means of implanted infusion pumps. Even better regulation of blood glucose in diabetic animals was obtained by the addition of predetermined pulses of insulin at higher flow rates than the basal flow rate, accomplished by use of a transcutaneously activated valve mechanism attached to the implanted infusion pump. We conclude that near-normal blood glucose concentrations can be maintained throughout the day in the dog by these means and that similar approaches, using implantable infusion pumps, in man may lead to better long-term control of diabetes than is currently available.

Animals↗

The effect of continuous heparin infusion for one year on serum cholesterol and triglyceride concentrations in the dog.

Fourteen normal dogs received continuous infusions of intravenous heparin for one year by means of an implantable infusion pump. Heparin wad admistered at an overall mean rate of 666 units/kg/day, a dose sufficient to prolong the Lee-White clotting time to greater than twice normal. Eight control, animals, under the same dietary and activity regimen, received continuous infusions of bacteriostatic water for one year by means of implanted pumps. Serum cholesterol concentrations rose to 50% above control values after one month of heparin infusion, and remained significantly (P less than 0.05) elevated at this level for the remaining 11 months. Serum triglyceride levels were unchanged. A possible mechanism for this elevation resides in the known effect of heparin to increase plasma free fatty acid concentrations by its activation of lipoprotein lipase. These results may have implications for the long-term use of heparin anticoagulation in the treatment of atherosclerotic states in man.

Animals↗

The Minnesota shunt.

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Ascites↗