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Biomedical subjects

B D Wigness

Publications and source records attributed to B D Wigness.

At least 19 recordsLinked to original sources
PubMed1986

A new peritoneovenous shunt.

For today's most common peritoneovenous shunt catheters, the high incidence of complications (disseminated intravascular coagulation [DIC], pulmonary problems, clotting of the intravascular end, and shunt kinking) results in limited use. We have designed a new peritoneovenous shunt catheter in which we improved mechanical biocompatibility with respect to both the peritoneum and the vasculature. The device consists of: a multimicroorifice ascites filter in a double-chambered collecting device, a tubular compression pump with an intratubular check-valve, and a check-valve catheter at the intravascular end for positive exclusion of blood by reflux or back diffusion. This configuration filters the proteinaceous material from the ascites fluid, transports the filtrate into the blood stream, maintains patency, act to prevent DIC by inhibiting the creation and transport of microthrombi into the cardiovascular system, and eliminates clot formation at the intravascular end.

Aged↗
PubMed1983

Failure to find amyloidosis in dogs treated with long-term intravenous insulin delivered by a totally implantable pump.

We examined tissues of seven non-diabetic mongrel dogs and four diabetic beagle dogs treated with constant insulin infusion via totally implantable pumps for from 210 to 880 days. Kidney and skeletal muscle tissue from all dogs were stained with Congo Red and thioflavin-T and appropriately examined. Kidney tissues from the beagle dogs were examined by electron microscopy. No amyloid deposits were found in any of these tissues. Thus, we cannot confirm an earlier report of amyloid occurring in dogs given long-term intravenous insulin. It is concluded that amyloidosis is not a necessary complication of long-term intravenous insulin infusion in dogs.

Amyloidosis↗
PubMed1982

Diabetic nephropathy in the uninephrectomized dog: microscopic lesions after one year.

Carefully age-matched, purebred male beagle dogs that underwent uninephrectomy one month after they were made diabetic with alloxan were used to establish a model of rapidly developing diabetic nephropathy in a large animal. The diabetic animals, all requiring insulin, were divided into two groups: one group with control by insulin injections permitting elevated fasting and postprandial serum glucose values and substantial glycosuria; the other with better control and with near-normal serum glucose levels and less glycosuria. By 1 year of diabetes both diabetic groups had renal lesions different from the uninephrectomized control animals but differing only slightly from one another. With light microscopy, diabetic dogs had increased mesangial thickening. With electron microscopic morphometry, glomeruli of diabetic subjects demonstrated increased fractional volumes of the total mesangium and of its cellular and matrix components and increased width of the GBM. These quantitative measures of diabetic nephropathy in the dog within 1 year of onset of the disease describe a model potentially useful in evaluating the efficacy of improved diabetic control in preventing or ameliorating diabetic nephropathy.

Animals↗
PubMed1982

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↗
PubMedDate not supplied

The Minnesota shunt.

Explore the source record for details and available documents.

Ascites↗
PubMedDate not supplied

The spring-driven implantable pump. A low-cost alternative.

In the current era of cost containment in medicine, manufacturing economics have become increasingly important. The authors devised an implantable pump powered by spring force from an elastomeric Belleville washer, which is also the outer flexible wall of the drug reservoir. Use of formed and injection molded parts provides for low-cost manufacturing, in contrast to the precision welded alternative designs. Additional advantages include insensitivity to changes in ambient temperature and pressure. Finite element modeling of the elastomer spring allows prediction of the effects of parameter changes on performance, so that expansions and reductions of scale can be made without compromising the uniform spring rate of the device. A concern that subcutaneous fibrous encapsulation might markedly alter reservoir pressure was not supported by experimental data. In a unit implanted subcutaneously in a dog, reservoir pressures measured over a 4 year period were stable. This new, simple, implantable infusion pump can serve as an economical vehicle for prolonged parenteral drug treatment of ambulatory subjects in circumstances where continuous single-rate infusion is appropriate.

Animals↗
PubMedDate not supplied

A totally implantable drug infusion defice: laboratory and clinical experience using a model with single flow rate and new design for modulated insulin infusion.

The Infusaid implantable infusion pump with a single delivery rate has maintained chronic intravenous heparin infusion in man for greater than 35 mo and for greater than 5 yr in the dog. Intra-arterial infuson of fluorodeoxyuridine has been maintained for greater than 8 mo in man. In a pilot study using a commercially available, transcutaneously controllable, magnetically activated valve for baseline superimposed bolus insulin infusion, the feasibility of maintaining near normal serum glucose in diabetic dogs was demonstrated. The effect of long-term intravenous cannulation was investigated; it was found that the intimal tissues of the vena cava surrounding the cannulae were largely unaltered and microemboli could not be detected in the lungs of the animals studied. Cannula plugging, which occurred on several occasions due to thrombus formation in the final centimeter of the cannula, has been solved by changes in pump design and refilling procedures. The problem of insulin precipitation in flow passages of the pump remains unsolved, but there are indications that substances entering the cannula from the blood may be involved. A new pump design for modulated insulin infusion is described.

Animals↗