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Biomedical subjects

W Payne

Publications and source records attributed to W Payne.

53 records · Page 3Linked to original sources
PubMed1983

Screening for transplant renal artery stenosis in hypertensive recipients using digital subtraction angiography.

Digital subtraction angiography was used in 10 renal allograft recipients with sustained hypertension after transplantation to detect transplant renal artery stenosis. Recipients with end-to-end vascular anastomoses were visualized adequately in the anteroposterior projection. Two cases of transplant renal artery stenosis were identified by digital subtraction angiography and then verified by catheter angiography. Patients with end-to-side vascular anastomoses may require additional oblique projections. Digital subtraction angiography is a safe, noninvasive and cost-effective screening procedure to diagnose transplant renal artery stenosis in most recipients. Catheter angiography can be applied more selectively to those recipients with stenosis observed by digital subtraction angiography or when more detailed imaging is required.

Adolescent↗
PubMed1983

The influence on pretransplant blood transfusions from random donors on immune parameters affecting cadaveric allograft survival.

The number of pretransplant blood transfusions (BT) from random donors influences the recipient's immune response status and suppressor cell number and function, as well as allograft survival. The 54% one-year survival rate for 104 cadaveric renal allograft recipients treated with azathioprine and prednisone was divisible into two groups: 74.5% in 51 patients receiving greater than 5 BT and 34% for 53 patients with less than 5 BT (P less than 0.02). Transfusions enhanced the benefit of HLA A, B, and DR compatibility on graft survival: 33 recipients of well-matched grafts (less than 2 A, B, and 0-1 DR mismatches) had a one-year survival rate of 94% when pretreated with greater than 5 BT, compared with 38% when receiving less than 5 BT (P less than 0.05). The graft survival of 73% (36/49) displayed by patients determined preoperatively to be weak immune responders was significantly better than the 36% survival (20/55) demonstrated by strong immune responders (P less than 0.01). The transfusion history correlated with immune responder status: 76% (39/51) of patients receiving greater than 5 BT were weak immune responders, whereas 81% (43/53) of patients receiving less than 5 BT were strong immune responders (P less than 0.001). Ninety-two percent (12/13) of patients with greater than 5 BT, but only 58% (10/17) of patients with less than 5 BT, had a normal number of OKT8+ T suppressor cells. Only 1 X 10(5) mononuclear cells from patients with greater than 5 BT rather than 4 X 10(5) cells from patients with less than 5 BT caused 50% suppression of a third-party MLC. Thus, patients receiving greater than 5 BT are more likely to display weak immune responses, normal numbers of OKT8 cells, strong suppressor function in vitro, and prolonged allograft survival.

Antibodies, Monoclonal↗
PubMed1982

The cellular target of cyclosporin A action in humans.

The balance of immunoregulatory T-helper (TH) and T-suppressor (Ts) lymphocytes was assessed in recipients of living donor and cadaveric grafts treated with azathioprine (Az) or cyclosporin A (CyA). Enumeration of each subpopulation was performed with monoclonal OKT antibodies. While Az-treated patients had a normal ratio of circulating peripheral blood helper-inducer (OKT4+) to suppressor-cytotoxic (OKT8+) cells, recipients treated with CyA showed a reduced ratio resulting from a decreased number of TH cells with normal numbers of Ts cells. The functional activity of Ts cells was evaluated by their capacity to suppress the primary mixed lymphocyte culture response of a normal, unrelated individual. Az-treated recipients showed greater suppression than the CyA-treated group, hemodialysis patients, or normal individuals. The function of TH cells was evaluated by the capacity of isolated patient peripheral blood T cells to promote pokeweed mitogen--driven immunoglobulin release by normal B cells, which then produced hemolytic plaques.l TH function was depressed in CyA-treated but not Az-treated recipients as compared with normal individuals. These results demonstrate distinctive profiles of immunoregulatory cells in patients immunosuppressed with Az or CyA. On the one hand, successfully engrafted Az-treated patients showed enhanced suppressor-cell activity with normal helper activity. On the other hand, CyA-treated patients had reduced helper-cell function with activity. On the other hand, CyA-treated patients had reduced helper-cell function with modestly increased suppressor-cell activity. These findings may provide guidelines for the selection of and parameters for monitoring the therapeutic efficacy of immunosuppressive agents in allograft recipients.

Azathioprine↗
PubMed1982

Pseudomonas peritonitis and continuous ambulatory peritoneal dialysis.

In a population of 44 patients receiving continuous ambulatory peritoneal dialysis (CAPD) for a total of 591 patient months, there were 104 episodes of peritonitis. The organisms were gram-positive in 65.4%, gram-negative in 23.1%, and cultures of the dialysate were sterile in 11.5%. Pseudomonas aeruginosa was the most frequently encountered gram-negative organism, accounting for 38.5% of the gram-negative infections or 9.6% of all infections. In all cases of P aeruginosa peritonitis, aminoglycoside antibiotic therapy for up to four weeks failed to eradicate the infection, and all patients required removal of the Tenckhoff catheter because of the presence of a sinus tract infection. We conclude that P aeruginosa is the most frequent cause of gram-negative peritonitis in patients receiving CAPD. The presence of a sinus tract infection should be suspected in all patients in whom peritonitis secondary to this organism develops. Removal of the Tenckhoff catheter will be required to cure the peritoneal infection.

Adult↗
PubMed1981

Composition of axolemma-enriched fractions isolated from bovine CNS myelinated axons.

Axolemma-enriched fractions were isolated from the white matter of bovine corpus callosum via a purified preparation of myelinated axons which were osmotically shocked and fractionated on a discontinuous density gradient. Two membrane fractions of differing density were obtained: both were somewhat enriched over white matter whole homogenate in specific activity of acetylcholinesterase and 5'-nucleotidase and maximal binding capacity for saxitoxin. Both membrane fractions contained appreciable amounts of 2', 3'-cyclic nucleotide 3'-phosphohydrolase; the specific activity of antimycin-sensitive NAPH-cytochrome c reductase and cytochrome c oxidase indicated low levels of contamination by microsomal and mitochondrial membrane. The myelin which is concomitantly isolated with the axolemma-enriched fractions has a lipid and protein composition comparable to that of myelin isolated by other procedures. Both axolemma-enriched fractions contain about one half of their dry weight as lipid comprised of approximately 25% cholesterol, 25% galactolipid (cerebrosides and sulfatides in a molar ratio of about 4:1) and 50% phospholipid, mostly choline phosphatides and ethanolamine phospholes in an equimolar ratio. The axolemma fractions are also enriched in ganglioside content relative to the myelin fraction. The polypeptides of the axolemma-enriched fractions range from 20,000 to over 200,000 in molecular weight; the predominant proteins are in the range from 50,000 to 69,000. The most dense axolemma-enriched fraction is over fourfold enriched in glycoprotein content compared with myelin, with at least 10 different molecular-weight classes of glycoproteins as identified by Schiff stain of polyacrylamide gel protein profiles. The differences and similarities in the molecular composition of axolemma-enriched preparations which have been characterized to date are discussed.

Animals↗
PubMed1975

The experimental contusion injury of the spinal cord in sheep.

The validity of reproduction of the controlled contusion injury to the spinal cord in the experimental animal is questioned. The dynamic pathology involving the microvasculature within the first two hours is illustrated using light microscopy. After 15-30 minutes swelling of axons and disruption of myelin sheaths become evident in most areas of white matter. After four hours microcysts have formed in the columns of white matter and are evidence of irreversible damage. Swelling of the cord following injury results from congestion, extravasation and intracellular swelling of neurones, rather than from any demonstrable increase in extracellular fluid. Oedema was only demonstrated with perfusion fixation. Isotope and contrast myelography were compared in the identification of the degree and extent of spinal cord swelling. Significant improvement in motor power was found in a group of paraplegic sheep treated with alpha-methyl paratyrosine. There was no significant improvement in the degree of recovery of motor power or sensation in those animals treated with intrathecal methyl prednisolone (Depo-Medrol). The histopathology in the crushed spinal cord tissue of the treated and untreated animals at various intervals of time was compared. Some possible explanations for the different patterns of clinical recovery in the treated animals are discussed.

Animals↗
PubMedDate not supplied

Instrumentation considerations of a clinical and a computerized technique for the measurement of foot angles.

Measurement of the foot angles either directly from the patient, from video images, or from radiographs is integral to podiatric clinical practice to confirm diagnoses and to plan, prescribe, and monitor treatment protocols. The reliability, precision, and accuracy involved in any measured value limits the validity and usefulness of the measurement to optimal patient management. Studies are described that ensured the accuracy and validity of the standard clinical tool, the universal goniometer (UG), by applying a calibration protocol. These same calibration angles were then measured by a computer-assisted human movement analysis system, the Ariel Performance Analysis System (APAS). The APAS was found to overestimate consistently the UG angular measures by less than 1 degree and this amount of error was considered clinically irrelevant. The angular results obtained by a clinician and a technician using the APAS on two separate days were tested and were found to be comparable and reliable to within 1 degree, and thus the analysis was deemed to be of excellent reliability and precision. The study found that clinicians could establish the accuracy and validity of their instruments by means of simple calibration, and that computer measures could be repeated on patients by a clinical or a technician. The simple calibration procedure described will assist the clinician to ensure that the measures obtained in the clinical setting have minimal measurement error and that the values can be confidently used to make decisions and draw clinical inferences.

Anthropometry↗
PubMedDate not supplied

Response of chickens carrying germline insert ALVA11 to challenge with a field strain of subgroup A avian leukosis virus.

The ALVA11 germline insert in chickens is a defective subgroup A avian leukosis virus (ALV) proviral insert that expresses a low-to-moderate level of subgroup A ALV envelope glycoprotein. Chicks carrying or lacking ALVA11 were evaluated for response to challenge by RPL-42, a pathogenic field strain of subgroup A ALV, by either exposure to chicks shedding RPL-42 or direct injection with various doses of RPL-42. Chicks carrying ALVA11 were significantly more resistant, as measured by infectious virus and viral antibody status, to horizontal infection and direct injection of RPL-42 than chicks lacking ALVA11.

Animals↗