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Biomedical subjects

J F Thompson

Publications and source records attributed to J F Thompson.

At least 235 records · Page 13Linked to original sources
PubMed1990

End-stage renal failure in children: 16 years' experience at one Australian centre.

Sixty-five children over one year and under 15 years of age began treatment for end-stage renal failure between 1973 and 1988. Sixty-one renal transplants were performed in 53 children, 39 of these were from living donors (38 were first-degree relatives and one was an emotionally related volunteer). Thirteen children, of whom seven had received transplants and six had not, died, including three children with functioning transplants; nine deaths occurred in the first eight years of the programme. Cumulative five-year and 10-year patient survival rates were 78% and 75%, respectively. Eighteen transplants failed, 12 as a result of rejection, five as a result of disease recurrence and one due to primary non-function. Cumulative five-year and 10-year transplant survival rates for first grafts were 66% and 53%, respectively. For living donor transplants these rates were 85% and 68%, respectively. Growth rates fell by 0.4 +/- 0.05 standard deviation score (SDS) per year in children undergoing dialysis, were normal in children with renal transplants receiving prednisone (change in SDS per year, -0.02 +/- 0.08) and increased by 0.36 +/- 0.07 SDS per year in children with transplants receiving cyclosporin A alone. Currently, 32 (82%) of 39 transplant recipients and 7 (58%) of 12 patients undergoing dialysis attend school or work full time. Although both dialysis and transplantation are acceptable therapies for children with end-stage renal failure, successful transplantation provides the best opportunity for satisfactory growth and development.

Actuarial Analysis↗
PubMed1990

Aortic occlusion and vascular isolation allowing avascular hepatic resection.

Occlusion of the supraceliac abdominal aorta and hepatic vascular isolation were employed in a series of 15 patients as a definitive method to allow avascular hepatic resection. The series was compared with an earlier group of patients treated conventionally. In the avascular hepatic resection group there was no mortality; hypotension did not occur at the time of hepatic vascular isolation; rapid, accurate excision of the hepatic lesions could be achieved in a bloodless field; resection of midline lesions and those involving the great veins was possible; and "segmentectomies," or resections crossing segmental boundaries, could be performed where previously formal hepatic lobectomies were required. Concomitantly, the greatest amount of uninvolved hepatic parenchyma remained in situ. There was increased ease of operative management, reduced blood loss, and reduced operating time (mean, 2.8 hours).

Adult↗
PubMed1990

Impact of duplex scanning on carotid endarterectomy.

Duplex ultrasound permits safe and accurate assessment of the extracranial vasculature. This paper reports the change in patterns of referral to a specialized vascular unit following its introduction; increased referrals were seen in all specialties except neurology. A widely available and reliable duplex service has revealed more extracranial vascular disease than was previously recognized, and has increased referrals for carotid endarterectomy, thereby increasing surgical workload.

Adult↗
PubMed1990

First rib resection for vascular complications of thoracic outlet syndrome.

The surgical approach to vascular complications of the thoracic outlet syndrome remains controversial. When present, removal of a cervical rib alone has produced disappointing results. Our experience of 29 consecutive first rib excisions over a 5-year period is presented. Of 20 cases with uncomplicated subclavian artery compression 19 were cured, and of six cases with aneurysm or thrombosis five were improved. Of 12 cases with neurological symptoms nine were cured and two were improved. It is suggested that first rib excision is the essential primary treatment for patients with arterial symptoms due to thoracic outlet syndrome.

Adult↗
PubMed1990

A quantitative analysis of T lymphocyte populations in human liver allografts undergoing rejection: the use of monoclonal antibodies and double immunolabeling.

The aim of this study was to quantitate T-cell populations infiltrating portal tracts, bile ducts and hepatic lobules in 82 biopsy specimens from 25 patients after orthotopic liver transplantation. Biopsy specimens taken immediately after revascularization of the graft were used as controls. Patients studied include 18 with initial rejection episodes, 11 with unresolved rejection, five with vanishing bile duct syndrome and eight patients with other forms of liver injury. Quantitation was done in a blinded fashion for the first 20 biopsy specimens. A double immunolabeling technique was used to simultaneously immunolabel bile duct structures (with anti-major histocompatibility complex class II or antikeratins) and lymphoid populations (with anti-CD2, anti-CD4 or anti-CD8). This facilitated the accurate quantitation of intraepithelial lymphocytes within bile ducts. This technique also enabled simultaneous detection of CD4 and CD8 antigens on lymphocytes in portal tracts. The predominant lymphocyte subtype within biliary epithelium during acute and chronic rejection was of the CD2+/CD8+ phenotype. CD8+/CD4+ ratio in bile ducts was approximately 5:1 in acute, unresolved and chronic rejection. In vanishing bile duct syndrome, double immunolabeling enabled the detection of destroyed interlobular bile duct remnants that were not apparent on routine hematoxylin and eosin staining. Attached to some of these structures were CD8+ lymphocytes. Lobular CD8+ cells were not prominent in acute rejection but increased significantly in biopsy specimens from patients with unresolved and chronic rejection. In chronic rejection, a selective increase was seen in these CD8+ cells in centrizonal regions.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1990

E.coli Fis protein activates ribosomal RNA transcription in vitro and in vivo.

An upstream activation region (UAR) contributes to the extremely high activity of the Escherichia coli ribosomal RNA promoter, rrnB P1, increasing its activity 20- to 30-fold over that of the same promoter lacking the UAR. We have used DNase footprinting to define three specific sites in the rrnB P1 UAR that bind Fis, a protein identified previously by its role in recombinational enhancer function in other systems. We find that purified Fis activates transcription from promoters containing these sites 10- to 20-fold in vitro at concentrations correlating with the filling of these sites. Three approaches indicate that Fis contributes to the function of the UAR in vivo. First, there is a progressive loss in the activity of rrnB P1-lacZ fusions as Fis binding sites are deleted. Second, an rrnB P1 promoter with a mutation in a Fis binding site has 5-fold reduced transcription activity in vivo, dramatically reduced Fis binding in vitro, and shows no Fis dependent transcription activation in vitro. Third, upstream activation is reduced 5-fold in a Fis- strain. We show that rRNA promoters derepress in response to the loss of Fis in vivo in accord with the predictions of the negative feedback model for rRNA regulation. We find that fis is not essential for the function of two control systems known to regulate rRNA, growth rate dependent control and stringent control. On the basis of these results, we propose roles for Fis and the upstream activation system in rRNA synthesis.

Base Sequence↗
PubMed1990

Determination of aconitate isomerase in plants.

We have developed a method for measuring aconitate isomerase (EC 5.3.3.7) in plants which depends on the release of tritium from labeled trans-aconitate. The released tritium is separated from labeled aconitate by passage through a column of strong anion-exchange resin. This method is more sensitive, simpler, and more specific than previous methods, especially with crude extracts. The validity of the method was demonstrated by a comparison of the quantity of tritium released with the amount of cis-aconitate isomerized and this comparison demonstrated an isotope effect. Aconitase did not interfere. The method was tested by measuring aconitate isomerase in crude extracts of several higher plant species and tissues and these analyses showed that wheat and corn have more aconitate isomerase than the other species tested.

Aconitate Hydratase↗
PubMed1990

Protein tyrosine kinase activity and its substrates in rat intestinal microvillus membranes.

Tyrosine phosphorylation has recently been recognized as a unique system involved in the regulation of cellular growth and differentiation. The role of tyrosine kinase activity in regulating intestinal proliferation has received little attention. The aim of this study was to document the presence of tyrosine kinase activity in intestinal microvillus membranes and to characterize the major endogenous tyrosine kinase substrates in microvillus membranes. Microvillus membranes, prepared from 21-day gestation fetal and adult CD rats by the calcium precipitation method, were solubilized in 0.1% Triton X-100 and incubated with [32P]adenosine triphosphate and (Glu80Tyr20)n, which is a heterogeneous population of synthetic peptides containing glutamate and tyrosine. Fetal, and to a lesser extent adult, microvillus membranes were shown to phosphorylate (Glu80Tyr20)n assayed by trichloroacetic acid-precipitable 32P incorporation as well as autoradiography of sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Preliminary identification of the endogenous substrates of microvillus membrane tyrosine kinase activity was determined by three techniques. First, phosphorylated microvillus membrane proteins were solubilized in sodium dodecyl sulfate and separated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the resultant gel was incubated in 1 mol/L KOH at 55 degrees C to selectively retain phosphotyrosine proteins. The patterns of tyrosine phosphorylation were dissimiliar in fetal and adult microvillus membranes; specifically, two major bands, 80 and 190 kilodaltons, were present in fetal microvillus membranes and were not prominent in adult microvillus membranes. These proteins were both phosphorylated on tyrosine residues as determined by phosphoamino acid analysis. Second, a specific antiphosphotyrosine monoclonal antibody was used to immunoprecipitate phosphotyrosine proteins from solubilized phosphorylated microvillus membranes. This antibody specifically immunoprecipitated proteins of molecular weights 36 and 68 from fetal and 33, 54, and 68 from adult microvillus membranes. Third, using a polyclonal antiphosphotyrosine antibody, Western blot analysis showed that the 68-kilodalton protein is the most abundant phosphotyrosine protein in fetal and adult microvillus membranes. These data will focus new investigations into the cellular mechanisms of the regulation of intestinal growth, particularly the role of luminal factors that may modulate microvillus membrane tyrosine kinase, and thus modulate enterocyte proliferation, differentiation, and function.

Animals↗
PubMed1990

Prospective randomised evaluation of a new cell saving device in elective aortic reconstruction.

In order to evaluate the clinical and haematological implications of salvage autotransfusion using the Haemolite device (Haemonetics, Leeds, UK), 67 aortic reconstructions were studied. Bank blood transfused during the operation fell from a median of four units in the control group to zero using the cell saver (P less than 0.0001), and wound drainage decreased from 250 to 200 ml (P = 0.12). Evidence of fibrinolytic and platelet activation was found during salvage, but no bleeding diathesis was encountered. There was no morbidity or mortality related to the technique, and median hospital stay was reduced in autotransfused patients. The Haemolite is a safe effective device for autotransfusion in elective aortic surgery, and can substantially reduce exposure of both patients and staff to the dangers of homologous blood.

Aorta, Abdominal↗
PubMed1990

Abscisic Acid inhibition of endosperm cell division in cultured maize kernels.

The response of developing maize (Zea mays L.) endosperm to elevated levels of abscisic acid (ABA) was investigated. Maize kernels and subtending cob sections were excised at 5 days after pollination (DAP) and placed in culture with or without 90 micromolar (+/-)-ABA in the medium. A decreased number of cells per endosperm was observed at 10 DAP (and later sampling times) in kernels cultured in medium containing ABA from 5 DAP, and in kernels transferred at 8 DAP to medium containing ABA, but not in kernels transferred at 11 DAP to medium containing ABA. The number of starch granules per endosperm was decreased in some treatments, but the reduction, when apparent, was comparable to the decreased number of endosperm cells. The effect on endosperm fresh weight was slight, transient, and appeared to be secondary to the effect on cell number. Mature endosperm dry weight was reduced when kernels were cultured continuously in medium containing ABA. Endosperm (+)-ABA content of kernels cultured in 0, 3, 10, 30, 100, or 300 micromolar (+/-)-ABA was measured at 10 DAP by indirect ELISA using a monoclonal antibody. Content of (+)-ABA in endosperms correlated negatively (R = -0.92) with endosperm cell number. On the basis of these studies we propose that during early kernel development, elevated levels of ABA decrease the rate of cell division in maize endosperm which, in turn, could limit the storage capacity of the kernel.

Journal Article↗
PubMed1990

Mazabraud's syndrome: intramuscular myxoma associated with fibrous dysplasia of bone.

A 53 year old male with a large swelling on the medial aspect of his right thigh was referred with a presumptive diagnosis of soft tissue sarcoma. However, biopsy revealed intramuscular myxoma and X-rays and CT scans suggested fibrous dysplasia of adjacent bone. Angiography had shown an expanded, hypervascular, intramedullary lesion in the femur, and a large avascular soft tissue mass lying medially in the distal thigh. Fibrous dysplasia of the femur was confirmed on bone biopsy. Subsequently one large and two smaller intramuscular myxomata were excised, with an uneventful postoperative course. This case illustrates Mazabraud's syndrome: the rare association between benign intramuscular myxoma and fibrous dysplasia of bone.

Femur↗
PubMed1990

Hemodynamics of conscious unrestrained baboons, including cardiac output.

A method is described for comprehensive hemodynamic study of undisturbed baboons (Papio hamadryas) that incorporates cardiac output measurement by thermodilution. Instrumentation includes arterial, aortic, and central venous catheterization by a surgical technique that does not require entry to peritoneal or thoracic cavities. It provides a means for right atrial indicator delivery with aortic temperature recording of thermodilution curves. Accuracy was confirmed by comparison to measurement by Swan-Ganz catheters. Diurnal variations of systemic arterial pressure in long-term study of conscious baboons were shown to result from significant increases in cardiac output by day (P less than 0.001), despite concomitant falls in systemic vascular resistance. The cardiac output values obtained were 0.13 l.min-1.kg-1 at night and 0.16 l.min-1.kg-1 by day. Comparison of these results to previous reports of cardiac output in baboons highlights the inadequacies of methods that require physical restraint or anesthesia. This technique also leaves the baboons intact for subsequent breeding or experimental use after catheter removal without the need for further surgery.

Animals↗
PubMed1990

Liver transplantation: an Australian experience.

During a 4 and a half-year experience, 283 patients were referred to the Australian National Liver Transplant Unit. Sixty (21%) were children. The major causes of liver failure in the adults were chronic active hepatitis (27%), primary biliary cirrhosis (13%), primary sclerosing cholangitis (12%), fulminant hepatic failure (9%), alcoholic cirrhosis (9%), and malignancy (9%). In the children they were biliary atresia (43%) and inborn errors of metabolism (18%). One hundred and ninety-seven (69%) were accepted for liver transplantation. Of 111 (39%) accepted for early transplantation, 18 (16%) died before a donor became available. There were 319 possible organ donors. Ninety patients (24 of them children) received 100 grafts. Sixty-three (70%) patients survived. For all recipients, 1-year survival was 73%. Two-, 3- and 4-year survivals were 67%. One- to 4-year survivals for adults with benign conditions were 76%, contrasting with results for those with hepatic malignancy (20% 1-year survival). Children weighing greater than 8 kg did well whether they received whole grafts (80% 1- to 4-year survival) or reduced grafts (75% 1- to 4-year survival). Infants weighing less than 8 kg who received reduced adult grafts did significantly worse (20% 1- to 4-year survival). All 8 (100%) patients with fulminant hepatic failure who received grafts survived, including 3 who received ABO-incompatible grafts, though 2 of these subsequently required retransplantation. Rehabilitation of survivors was excellent with 91% of adults and 94% of children pursuing normal activities. Only 2 (2%) grafts failed with primary nonfunction, both in infants because of infarction. Graft survival was significantly worse (p less than 0.01) in patients with a positive direct crossmatch test against the donor. We calculate that the need for liver transplantation in Australia is approximately 7 per million of population per year. Increased donor offers are required to avoid deaths of patients on the waiting list. Reduced-size adult livers are successful for children and have alleviated considerably the critical shortage of pediatric donor livers. Liver transplantation is a highly satisfactory treatment for patients with benign liver disorders but not for those with malignant conditions. Patients with fulminant hepatic failure not responding to conservative therapy should be treated by liver transplantation. In this and other urgent circumstances, an ABO-incompatible liver may be lifesaving though retransplantation with an ABO-compatible liver may subsequently be required. The results of liver transplantation for nonmalignant conditions have improved steadily with clinical experience, with 1- and 2-year patient survivals during the past 28 months of 85%.

Adult↗
PubMed1990

Varicose vein surgery using a pneumatic tourniquet: reduced blood loss and improved cosmesis.

A prospective controlled randomised study has been performed of 100 consecutive patients undergoing varicose vein surgery. One group underwent saphenofemoral flush ligation and multiple lower leg avulsions with the leg exsanguinated with a Rhys-Davies cuff, and ischaemia maintained with a pneumatic tourniquet. The other group underwent identical surgery but with a 30 degree head down tilt only. Blood loss was significantly less (13.5 +/- 12 ml vs 133 +/- 78 ml; P less than 0.01) and postoperative cosmesis was significantly improved in patients in the tourniquet group. Operating time was similar (27 +/- 11 min vs 30 +/- 13 min) in the two groups.

Esthetics↗
PubMed1990

The justification for surgical treatment of metastatic melanoma of the gastrointestinal tract.

Fifty-six patients with symptomatic metastatic melanoma of the gastrointestinal tract (GIT) treated surgically at the Sydney Melanoma Unit between 1974 and 1989 were reviewed. The majority of these patients presented with abdominal pain or symptoms of anemia. The small intestine was the site of metastasis in more than 80 per cent. The mean over-all survival time was 11.7 months (range of one to 60 months) after surgical treatment of a first metastasis to the GIT and 3.6 months (range of zero to 12 months) postoperatively for a second GIT metastasis. Forty-four of the patients reported complete relief of their symptoms postoperatively. The results suggest that an aggressive approach to symptomatic GIT metastases from malignant melanoma is justified both to relieve distressing symptoms and to prolong life.

Adolescent↗