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Biomedical subjects

L D Cowgill

Publications and source records attributed to L D Cowgill.

At least 37 records · Page 2Linked to original sources
PubMed1992

Pathophysiology and management of anemia in chronic progressive renal failure.

Hypoproliferative anemia is a predictable and serious complication of progressive renal failure and contributes significantly to the overall morbidity of the uremic state. Until recently, there has been no satisfactory therapy to resolve the anemia. Now the anemia can be explicitly corrected with erythropoietin-replacement therapy, and the clinical debility generally attributable to renal insufficiency can be lessened and retarded. Anemia must no longer be regarded as an intractable consequence of the uremic syndrome and should be managed as conscientiously as the other polysystemic features of uremia.

Anemia↗
PubMed1991

The Fontan procedure: a historical review.

Complete bypass of the right ventricle was first performed successfully and subsequently reported by Fontan and Baudet for patients with tricuspid atresia. By eliminating congenital and surgical shunts, ventricular volume overload and pulmonary hypertension were avoided. A logical extension of its predecessor, the partial right heart bypass procedure introduced by Glenn, the Fontan operation has great application for patients with various forms of univentricular heart. It is one of the historic advances in the surgical treatment of congenital heart disease.

Cardiac Surgical Procedures↗
PubMed1988

Effects of combination cyclosporine/mizoribine immunosuppression on canine renal allograft recipients.

Heterotopic renal allografts following bilateral nephrectomies were placed in 21 healthy mongrel dogs. One group of 11 dogs received cyclosporine (5 mg/kg/24 hr, orally), and 1 group of 10 dogs received cyclosporine and mizoribine (5 mg/kg and 3 mg/kg/24 hr, orally). Body weights, blood cell counts, serum chemistry profiles, serum electrolyte levels, urinalysis with cytology and culture, lymphocyte stimulation assays, immunoglobulin levels, whole blood levels of cyclosporine, and serum levels of mizoribine were followed. At the end of each survival period, necropsy and histopathologic examinations were performed. The mean survival time for the cyclosporine group was 12.8 +/- 7 days. The mean survival time for the cyclosporine/mizoribine group was 33.6 +/- 16.4 days, significantly longer (P = .0006) than the cyclosporine group. Death in the cyclosporine/mizoribine group was attributed to the combined effects of renal allograft rejection and development of a mizoribine-dependent enteritis. Serum levels of mizoribine were greater in the last half of the survival period due to compromised renal excretion of the drug. There were no complications due to infection, myelosuppression, or hepatotoxicity. Combination cyclosporine/mizoribine immunosuppression enhanced canine renal allograft survival in this study. Monitoring serum concentrations of mizoribine is imperative to determine toxic (enteritis) levels. Availability of an intravenous form of mizoribine would facilitate immunoregulation during periods of variable intestinal absorption or renal excretion.

Animals↗
PubMed1988

Semiautomated renal region-of-interest selection method: validation in a dog model.

A successful method of automated region-of-interest (ROI) selection by polar edge search for use in technetium-99m-diethylenetriaminepentacetate (99mTc-DTPA) renography is presented in a dog model. The accuracy of the resultant ROI was tested by comparing renal uptake within the ROI to simultaneously monitored arterial 99mTc-DTPA concentration. The automatically selected ROI resulted in renal uptake curves that better matched arterial clearance than either systematically larger and smaller ROIs or a manually chosen ROI.

Algorithms↗
PubMed1988

Effects of mizoribine on canine renal allograft recipients.

Heterotopic renal allograft transplantation and bilateral nephrectomies were performed on 12 mixed-breed dogs. Histoincompatibility was confirmed by serologically defined and lymphocyte-defined antigen testing. Mizoribine (5 mg/kg, q 24 h) was administered orally starting the day of surgery. Body weights, blood cell counts, serum biochemical and electrolyte values, immunoglobulin concentration, and serum mizoribine concentrations were determined. Complete urinalyses, including bacteriologic culturing and lymphocyte stimulation assays were performed. The mean survival time for the allograft recipients was 20 +/- 14 days; significantly longer than nontreated historic controls surviving 8.1 +/- 0.6 days (P = 0.0098). Death was attributed to the combined effects of renal allograft rejection and development of a mizoribine-dependent gastroenteritis. Serum mizoribine concentrations were greater in dogs undergoing rapid allograft rejection because of compromised renal excretion of the drug. This resulted in a rapid onset of gastroenteritis. There were no complications resulting from infection, myelosuppression, or hepatotoxicosis.

Alanine Transaminase↗
PubMed1987

A practical approach to prosthetic valve endocarditis.

Prosthetic valve endocarditis (PVE) is an infrequent but dread complication, occurring in 1 to 2% of patients both early (less than 60 days) and late postoperatively. Diagnosis is always (99%) possible by two sets of blood cultures, but occasional exogenous causes of bacteremia may cloud the diagnosis, as will culture-negative cases of PVE and skin contaminants. With obvious exogenous sources of bacteremia, achieving sterile blood cultures after eradication of the noncardiac source permits discontinuation of antibiotics after two weeks. When skin contaminants are suspected, withholding antibiotics and obtaining two sets of blood cultures is recommended, because the bacteremia with PVE is continuous. Preventive measures, including perioperative antibiotics, are warranted but will probably not significantly reduce the low incidence of infection already achieved. The major cause of improved survival in recent years is earlier operation (valve rereplacement). This has been demonstrated in the last ten years and is absolutely indicated for major heart failure, ongoing sepsis, fungous etiology, valve obstruction, new-onset heart block, and unstable prosthesis by fluoroscopy.

Anti-Bacterial Agents↗
PubMed1987

Ventricular septal defect due to nonpenetrating chest trauma: use of the intra-aortic balloon pump.

Nonpenetrating traumatic ventricular septal defect is rare. A triad of blunt chest trauma, holosystolic precordial murmur, and ECG abnormalities should suggest the diagnosis. Surgical repair, when indicated by progressive failure, rising pulmonary artery pressures, or significant (2:1 or larger) left-to-right shunt, has been shown to be very effective. Optimally, a period of several weeks from the injury should elapse before operative intervention is undertaken. Intra-aortic balloon pump may be helpful to stabilize patients acutely, and, in selected instances, allow delay of surgical repair so that the tissue around the defect may hold sutures more securely.

Adolescent↗
PubMed1986

Localization of phosphorus metabolites and sodium ions in the rat kidney.

Relative amounts of phosphorus-containing metabolites and sodium ions present in different regions of the in vivo rat kidney were obtained using a surface-coil probe and recently developed NMR rotating-frame methods. During altered physiologic states, changes in distribution of metabolites and sodium ions within the kidney were identified in one-dimensional metabolite maps. This technique may have important applications to disorders commonly found in clinical medicine.

Acidosis↗
PubMed1986

Repair of pulmonary valve insufficiency using an autologous monocusp.

A 3 1/2-year-old boy experienced right ventricular failure approximately two years after an operation for critical pulmonic stenosis. Severe pulmonary and tricuspid valvular insufficiency was documented echocardiographically and at cardiac catheterization. Treatment consisted of a tricuspid valve annuloplasty and creation of an autologous monocusp valve using the anterior wall of the pulmonary artery. The procedure was well tolerated, and early competence of the pulmonary valve was shown intraoperatively by pressure recordings and postoperatively by Doppler echocardiography. However, at recatheterization one year later, there was no evidence that the monocusp valve was functioning. This experience does not support the prior successful application of this technique in animals.

Cardiac Catheterization↗
PubMed1986

Aortoventriculoplasty in a five-month-old infant: an alternative approach to the treatment of critical aortic stenosis in infancy.

A newborn with critical aortic stenosis and anular hypoplasia was treated with an aortic valvotomy using inflow occlusion. Five months later, important valvular insufficiency and residual stenosis necessitated aortic valve replacement. An aortoventriculoplasty using a 19 mm St. Jude Medical Valve was successfully performed with a good hemodynamic response.

Angiography↗
PubMed1979

Evidence for an intrinsic renal tubular defect in mice with genetic hypophosphatemic rickets.

To investigate the role of parathyroid hormone (PTH) and(or) an intrinsic renal tubular reabsorptive defect for phosphate in mice with hereditary hypophosphatemic rickets, we performed clearance and micropuncture studies in hypophosphatemic mutants and nonaffected littermate controls. Increased fractional excretion of phosphate in mutants (47.2+/-4 vs. 30.8+/-2% in controls) was associated with reduced fractional and absolute reabsorption in the proximal convoluted tubule and more distal sites. Acute thyropara-thyroidectomy (TPTX) increased phosphate reabsorption in both mutants and controls with a fall in fractional phosphate excretion to congruent with7.5% in both groups indicating that PTH modified the degree of phosphaturia in the intact mutants. Absolute reabsorption in the proximal tubule and beyond remained reduced in the mutants, however, possibly because of the reduced filtered load. Serum PTH levels were the same in intact mutants and normals as was renal cortical adenylate cyclase activity both before and after PTH stimulation. To evaluate the possibility that the phosphate wasting was caused by an intrinsic tubular defect that was masked by TPTX, glomerular fluid phosphate concentration was raised by phosphate infusion in TPTX mutants to levels approaching those of control mice. Phosphate excretion rose markedly and fractional reabsorption fell, but there was no change in absolute phosphate reabsorption in either the proximal tubule or beyond, indicating a persistent reabsorptive defect in the absence of PTH. We conclude that hereditary hypophosphatemia in the mouse is associated with a renal tubular defect in phosphate reabsorption, which is independent of PTH and therefore represents a specific intrinsic abnormality of phosphate transport.

Animals↗
PubMed1979

Percutaneous nephropyelocentesis and nephropyelostomy in the dog: a description of the technique.

Percutaneous nephropyelocentesis or nephropyelostomy was done on 20 anesthetized dogs of both sexes with the aid of fluoroscopy. The upper urinary tracts were visualized by the use of IV radiopaque contrast material and distended by application of an abdominal compression band positioned over the caudal abdomen. Renal pelvic urine was readily obtained by both procedures in each dog. Bloody urine was an infrequent result, and usually occured only after repeated attempts had been made to enter the renal pelvic lumen. To ascertain the degree of renal parenchymal damage caused by passage of the needle and catheter, dogs were euthanatized and necropsied on the 1st, 3rd, 7th, and 14th days after the procedure was done. Repair of the tissue damage was rapid and the lesions were difficult to visualize grossly by the 14th day.

Animals↗
PubMedDate not supplied

Comparison between the scintigraphic uptake and plasma clearance of 99mTc-diethylenetriaminepentacetic acid (DTPA) for the evaluation of the glomerular filtration rate in dogs.

The scintigraphically measured percentage dose uptake of 99mTc-DTPA by the kidneys and the plasma clearance of 99mTc-DTPA have been reported to correlate well with inulin clearance. These two parameters were evaluated in seven dogs with known or suspected naturally occurring renal disease and compared to simultaneously measured renal inulin clearance. Correlation between inulin clearance and the 99mTc-DTPA plasma clearance was better (p = .0016) than the correlation between the percentage DTPA uptake by the kidney. It was concluded that measurement of 99mTc-DTPA plasma clearance is a more accurate method to estimate global glomerular filtration rate (GFR) than the percentage kidney uptake.

Animals↗