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Biomedical subjects

P Stanley

Publications and source records attributed to P Stanley.

At least 163 records · Page 9Linked to original sources
PubMed1987

Long-term daily study of blood volume in cardiac autotransplanted dogs.

Cardiac transplantation is followed by the interruption of afferent nerves to the heart. Knowing that some of the afferent nerves are responsible for the homeostasis of the blood volume, we undertook a serial and long-term study of the blood volume in 25 dogs with denervated hearts. The animals were autotransplanted in order to eliminate repercussions linked to rejection and to its treatment. To discern the effects of surgery and of extracorporeal circulation from those of denervation, a group of 11 control dogs was operated upon and subjected to a period of extracorporeal circulation. In both groups, serial and long-term studies of blood volume were carried out daily with 131I-labeled albumin. Analysis of the results demonstrated that in the hours following surgery, blood volume is significantly decreased by 11% in the control group and by 22% in group 2. By the 5th postoperative day, the blood volume had increased gradually to attain normal values in both groups. At the 2nd postoperative week, the total blood volume remained normal in the control group, whereas blood volume had increased by 5.7% in the autotransplanted dogs, this being due to a 38% increase of the plasmatic phase. This increment persisted from the 14th to the 42nd postoperative day and attained 7.4%. Our conclusion is that the variations in blood volume during the 1st postoperative week in the autotransplanted heart are inherent in surgery and in extracorporeal circulation. Afterwards, the hypervolemia shown in the transplanted dogs is secondary to cardiac denervation.

Afferent Pathways↗
PubMed1987

Posttransplant renal artery stenosis: angiographic study in 32 children.

Renal artery stenosis was identified in 32 children who either developed or had an exacerbation of hypertension after renal transplantation. One child developed renal artery stenosis in two sequential transplants. Renal artery stenosis occurred only in those patients who received transplants from cadavers. In 14 of the 15 patients with end-to-end renal artery anastomoses, the stenosis was at the anastomosis. In 14 of the 18 patients with end-to-side anastomoses, the stenosis was distal to the anastomosis.

Angiography↗
PubMed1987

[Effect of cardiac rejection on blood volume].

The variations of blood volume after autotransplantation have been documented recently by our group. Since, in the homotransplanted heart, acute rejection affects cardiac function we felt that the blood volume variations might be different than that of the autotransplants. In thirty-one immunosuppressed dogs with an orthotopic homotransplanted heart, daily assessments of blood volume with iodine 131 tagged albumin was carried out from preoperative period (control) until death from acute rejection. In the immediate postoperative period there was a significant fall of 21% of the blood volume caused by a 20% fall of plasmatic volume and of a 23% fall in erythrocyte volume. From the second to the fifth postoperative day in spite of persistence of a low erythrocyte volume the blood volume progressed to normal due to a compensatory increase of the plasmatic volume. In the terminal phase of rejection there was a 32% increase of the plasmatic volume leading to an 8% increase of the total blood volume.

Animals↗
PubMed1987

[Congenital unilateral absence of a pulmonary artery].

Congenital absence of a pulmonary artery is a rare entity often followed by complications. Up to now only two patients have done well after revascularization of the affected lung. We have had the opportunity to operate upon the two youngest patients suffering from an absence of a right or left pulmonary artery. In both cases revascularization of the lung was achieved with the use of a PTFE graft. In the second case, a non previously described technique has been applied successfully. Both children have been doing well up to now. This experience has led us to believe that revascularization of the affected lung should be done even in very young patients and that pulmonary hypertension may regress.

Humans↗
PubMed1986

Lec1A Chinese hamster ovary cell mutants appear to arise from a structural alteration in N-acetylglucosaminyltransferase I.

The biochemical and kinetic properties of UDP-GlcNAc:alpha-D-mannoside (GlcNAc to Man alpha 1,3) beta 1,2-N-acetylglucosaminyltransferase I (GlcNAc-TI) have been investigated in the Chinese hamster ovary glycosylation mutant Lec1A. Previous studies showed that, whereas Lec1A cells synthesize complex carbohydrates at levels consistent with partial GlcNAc-TI action, no GlcNAc-TI activity was detected in Lec1A cell-free extracts (Stanley, P., and Chaney, W. (1985) Mol. Cell. Biol. 5, 1204-1211). It is now reported that, under altered reaction conditions, GlcNAc-TI activity can be measured in Lec1A cell extracts. The GlcNAc-TI enzyme in Lec1A.2C has a pH optimum of 7.5 (compared with 6.25 for the parental enzyme) and apparent Km values for Man5GlcNAc2Asn and UDP-GlcNAc that are, respectively, 21- and 44-fold higher than the apparent Km values of GlcNAc-TI from parental Chinese hamster ovary cells. Two independent Lec1A mutants possess GlcNAc-TI activities with similarly altered biochemical and kinetic properties. In fact, under optimal assay conditions for each cell line, the level of GlcNAc-TI in Lec1A extracts is equal to that of parental Chinese hamster ovary cell extracts. Interestingly, the two glycosylation sites of the G glycoprotein of vesicular stomatitis virus are processed quite differently in Lec1A cells. The glycopeptide nearest the carboxyl-terminal appears to be a preferred substrate for the Lec1A GlcNAc-TI activity. The combined data suggest that the Lec1A mutation affects the gene that codes for GlcNAc-TI, giving rise to a structurally altered glycosyltransferase with different biochemical properties.

Animals↗
PubMed1986

Advances in pediatric tumor imaging.

The continuing improvement in the outlook for pediatric malignant disease depends on modern imaging techniques. The roles of magnetic resonance imaging, computed tomography, ultrasound, nuclear radiology, and angiography are discussed in relationship to the accurate staging of the primary tumor and the effect of therapy.

Angiography↗
PubMed1986

Methyldopa: an often overlooked cause of fever and transient hepatocellular dysfunction.

The clinical features and laboratory findings of 78 cases of methyldopa fever are reported. This drug reaction masqueraded as a variety of acute infectious diseases including septicaemia, meningitis, hepatitis and gastroenteritis, occurred within five weeks of starting the drug and appeared to be unrelated to its dosage. Eosinophilia and skin rashes were conspicuous by their absence. In the majority of patients, symptoms were relieved within 48 hours of the withdrawal of the drug. Sixty-one per cent of patients had biochemical evidence of liver damage but jaundice was uncommon. This pattern of mild hepatotoxicity in patients with early febrile reactions to methyldopa contrasts with the later more serious viral hepatitis-like illness due to the drug.

Adult↗
PubMed1986

Lectin-resistant CHO cells: selection of four new pea lectin-resistant phenotypes.

The cytotoxic plant lectins from P. sativum have been used to select new lectin-resistant mutants from Chinese hamster ovary (CHO) cells. Two novel phenotypes that behave recessively but fall into the same complementation group have been termed Lec13 and Lec13A. Both of these mutant types are phenotypically reverted to pea lectin sensitivity following growth in L-fucose. In contrast, two other unique phenotypes behave dominantly in somatic cell hybrids and maintain their pea lectin-resistance in the presence of L-fucose. They have been termed LEC14 and LEC18, respectively. The lectin-resistance and complementation properties of the four new mutant types suggest that they define three different glycosylation genes of the CHO genome.

Animals↗
PubMed1986

High-frequency transfection of CHO cells using polybrene.

High-frequency transfection of CHO cells has been achieved for several plasmids, a cosmid library, and genomic DNA using Polybrene and dimethyl sulfoxide. All plasmid transfectants examined were stable and exhibited plasmid sequences in genomic DNA. The method is simple, reproducible, and succeeded with several independent CHO clones in the presence or the absence of carrier DNA, even at very low concentrations of plasmid DNA.

Animals↗
PubMed1986

Pediatric hypertension: an approach to imaging.

Since 1981, we have made diagnoses of secondary hypertension using state of art imaging equipment in 18 pediatric patients. The most valuable tests were ultrasound in identifying renal parenchymal disease, computed body tomography for adrenal tumors and intra-arterial renal angiography for renovascular disorders. Based on our experience, we have formulated an algorithm for the evaluation of the hypertensive pediatric patient. The initial step is careful clinical and laboratory screening to identify those patients that are likely to have essential hypertension and who should not undergo imaging tests. In the cases where there is a possible secondary etiology, renal ultrasound is usually performed first to identify parenchymal disease. If catecholamines are elevated, then abdominal computed tomography is the initial test. If no etiology is identified from these noninvasive studies, then direct intraarterial renal angiography is performed. The authors do not feel that excretory urography, radionuclide renography, intravenous digital subtraction angiography or selective renal vein sampling for renin are useful or practical screening tests for renovascular hypertension.

Adolescent↗
PubMed1986

Two Chinese hamster ovary glycosylation mutants affected in the conversion of GDP-mannose to GDP-fucose.

A biochemical basis for the pea and lentil lectin resistance of two Chinese hamster ovary (CHO) cell mutants, Lec13 and Lec13A, was investigated. Studies of the G glycopeptides of vesicular stomatitis virus grown in the mutants indicated that Lec13 cells essentially lack the ability to add fucose to complex carbohydrates while Lec13A cells synthesize significant proportions of fucosylated, complex moieties. However, both mutants were known to be reverted to lectin sensitivity by growth in L-fucose, making them similar to the mouse lymphoma mutant, PLR1.3, which is defective in the conversion of GDP-mannose to GPD-fucose [M. L. Reitman, I. S. Trowbridge, and S. Kornfeld (1980) J. Biol. Chem. 255, 9900-9906]. Optimal conditions for the production of GDP-fucose from GDP-mannose by CHO cytosol were found to occur at pH 8 in the presence of 7.5 microM GDP-mannose, 15 mM Mg2+, 0.2 mM NAD+, 0.2 mM NADPH, 10 mM niacinamide, 5 mM ATP, and 50 mM Tris-HCl. Under these conditions, Lec13 cytosol produced no detectable GDP-fucose nor GDP-sugar intermediates while Lec13A cytosol produced significant quantities of both. Mixing experiments with Lec13 cytosol identified the first enzyme of the conversion pathway (GDP-mannose 4,6-dehydratase, EC 4.2.1.47) as the site of the block. In addition to being markedly reduced, the Lec13A 4,6-dehydratase activity was relatively insensitive to changes in pH in comparison to the activity in parental cytosol, suggesting that Lec13A cells might possess a structurally altered GDP-mannose 4,6-dehydratase enzyme.

Animals↗
PubMed1986

Percutaneous drainage of hepatic abscesses in children.

Ultrasound guided percutaneous drainage of seven hepatic abscesses in five pediatric patients was performed. Abscesses were pyogenic in four of the patients and amebic in one. All patients recovered completely without surgical intervention. Methodology necessary in the pediatric patient is stressed.

Adolescent↗
PubMed1986

Percutaneous aspiration and catheter drainage of abscesses.

Since 1980, we have treated 23 abscesses in 21 pediatric patients by percutaneous needle aspiration or catheter drainage or both. Percutaneous management has been completely successful in 16 of 21 patients and 18 of the 23 abscesses. In two patients, abscess drainage was technically successful and improved the patient's condition, but surgery was later required because of other complicating conditions. There were three failures of percutaneous aspiration or catheter drainage. Three serious complications occurred, but there was no mortality. Percutaneous management of abscesses is often a safe and effective procedure in pyogenic liver and postoperative abscesses.

Abdomen↗
PubMed1986

Pediatric percutaneous nephrostomy: experience with 50 patients.

Percutaneous nephrostomy tube placement was performed on 50 children with obstructed urinary tracts. The youngest patient was 3 days old and the smallest weighed 1,400 gm. The most common indication was obstruction after ureteral reimplantation (17 cases) followed by preoperative placement for pelvioureteral junction obstruction (15 cases). Infection was the most common presenting feature (14 cases), followed by a mass (11 cases) and renal failure (11 cases). Catheter placement was performed with basal sedation and general anesthesia was not used. There were no failures. In 26 patients no further surgery was required, including 16 of the 17 patients who had obstruction secondary to ureteral reimplantation. The only 2 significant complications were sepsis after catheter exchange in 1 patient and brisk hematuria upon placement of the catheter in another patient. Percutaneous nephrostomy tube placement is the method of choice for temporary relief of obstruction of the upper urinary tracts in children, since the hazards of surgery and general anesthesia are avoided.

Acute Kidney Injury↗