The role of intraoperative salvage autotransfusion.
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Blood Transfusion, Autologous↗
Biomedical subjects
J F Thompson
Publications and source records attributed to J F Thompson.
Empirical estimation of protein-induced DNA bending angles: applications to lambda site-specific recombination complexes.
Protein-induced DNA bending is an important element in the structure of many protein-DNA complexes, including those involved in replication, transcription, and recombination. To understand these structures, the path followed by the DNA in each complex must be established. We have generated an empirical relation between the degree of bending and the altered electrophoretic mobility in polyacrylamide gels that allows estimation of protein-induced bends. This technique has been used to analyze 17 different protein-DNA complexes formed by six proteins including the four proteins involved in lambda site-specific recombination. The simplicity of this technique should make it useful in estimating angles for the construction of models of protein-DNA complexes and readily applicable to many systems where questions of higher-order structure are important for understanding function.
Bacteriophage lambda↗
The role of nuclear medicine in liver transplantation.
The role of hepatobiliary isotopic scanning after liver transplantation was assessed in the first 12 adult patients in the Pilot National Liver Transplantation Programme who underwent this procedure at the Royal Prince Alfred Hospital. Iminodiacetic-acid derivative (HIDA) studies were useful in the non-invasive assessment of hepatic function and biliary excretion. The following four clinical situations were assessed by hepatobiliary scans: early graft function; rejection episodes; vascular complications; and biliary-tract problems. Nuclear medicine has an important and valuable role in the postoperative monitoring of patients after liver transplantation. The studies are non-invasive and can be performed readily at the bedside in the intensive care unit.
Adolescent↗
The living, related kidney donor: a follow-up study.
Thirty-eight children received 41 living-donor kidney transplants in an 11-year period; 73% of the grafts are functioning well. The parents of the recipients were the usual donors (60% of the donors were mothers and 25% of the donors were fathers); however, there were five donations from siblings and one donation from a donor who was related emotionally to the recipient. The most frequent perioperative complications were respiratory but these were not serious and did not cause any long-term sequelae. The principal long-term complications that related to--or were perceived by the donor as being related to--the procedure were incisional pain (20% of donors) and depression (25% of donors). These were not related to the success or otherwise of the transplantation. At follow-up, five (12%) donors had diastolic blood pressure levels of greater than 90 mmHg or were receiving antihypertensive therapy; this prevalence is similar to that which is found in the community. Two donors had urinary protein excretion rates of greater than 200 mg/24 h (210 mg/24 h and 350 mg/24 h, respectively). Creatinine clearance rates fell by 15% in women and by 5% in men. Serum creatinine levels had risen by 40% in men and by 35% in women after the nephrectomy; these levels had changed little at follow-up. All donors said that they would have proceeded with the donation even with fore-knowledge of what they would experience during and after the donation. Living-donor renal transplantation is a procedure with very low but definite operative risks which nevertheless provides a means for the early effective replacement of renal function in children with growth potential. The donors are enabled to make a major contribution to the life and well-being of the child, and they regard the perioperative complications as minimal. There do not appear to be any serious long-term complications of renal donation.
Adolescent↗
Helical-repeat dependence of integrative recombination of bacteriophage lambda: role of the P1 and H1 protein binding sites.
The efficiency of site-specific recombination of bacteriophage lambda was found to depend on the spacing between distant protein binding sites. Insertions and deletions of up to 30 base pairs were made in the nonessential regions between the H1 and H2 protein binding sites. Recombination was found to occur in substrates with changes of integral multiples of a DNA helical repeat, whereas recombination was defective in substrates with nonintegral changes. The lambda recombinogenic complex is especially interesting because two different proteins are involved: integration host factor (IHF), which has been shown to bend DNA, and the phage-encoded integrase protein (Int), which has been shown to have two distinct DNA-binding domains. The importance of angular displacement of protein binding sites was confirmed by addition of ethidium bromide to defective substrates. Significant stimulation of recombination was observed when sufficient drug intercalated and unwound the DNA to allow improved orientation of sites. The orientation effects are dependent on supercoiling, as spacing is less important in conditions where supercoiling and the P1-H1 sites are not required for recombination.
Bacteriophage lambda↗
Specific receptors for epidermal growth factor in rat intestinal microvillus membranes.
Epidermal growth factor (EGF) is present in high concentrations in milk, salivary, and pancreaticobiliary secretions. EGF, delivered to the intestinal lumen by these fluids, appears to influence intestinal proliferation. Because EGF exerts its mitogenic effect through binding to specific membrane-bound receptors, binding studies of 125I-labeled EGF to purified microvillus membrane (MVM) preparations from fetal, newborn, and adult rat small intestine were performed. Using the membrane filter technique, binding of 125I-EGF to adult MVM was specific, saturable, and reversible. Adult and fetal MVM binding was rapid and reached a plateau after 30 min at both 20 and 37 degrees C. No binding was detected at 4 degrees C. Specific binding increased linearly from 0 to 75 micrograms MVM protein. Scatchard analysis revealed a single class of receptors in fetal and adult MVM with an association constant of 1.0 +/- 0.35 X 10(9) and 2.3 +/- 1.6 X 10(9) M-1, respectively. Binding capacity was 435.0 +/- 89 and 97.7 +/- 41.3 fmol 125I-EGF bound/mg MVM protein for fetal and adult MVM, respectively. Newborn MVM binding was negligible. After binding, cross-linking utilizing disuccinimidyl suberate, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, autoradiography revealed a 170-kDa receptor. These data demonstrate specific receptors for EGF on MVM of rat small intestine and, thus, suggest a mechanism for the intraluminal regulation of enterocyte proliferation by EGF.
Animals↗
Liver graft revascularization by donor portal vein arterialization following "no touch" donor hepatectomy.
Unsatisfactory immediate function of the transplanted liver together with technical complications contribute to a persisting early mortality for hepatic transplantation in the 20% range. We report our initial clinical experience with methods, one not previously used clinically, that resulted in uniformly well-functioning liver grafts in 11 patients and contributed to a satisfactory success rate for the procedure. Donors were heart-beating. During the donor operation all manipulations of the liver were avoided until after cold preservation, achieved by external cooling at the same time as circulatory interruption, donor exsanguination and perfusion of the liver with cold oxygenated fluid of "extracellular" type. The organs were then gently dissected. At transplantation the livers were revascularized with arterial blood shunted from the recipient iliac artery to the graft portal vein after completion of the suprahepatic IVC anastomosis. The infrahepatic IVCs and hepatic arteries were then joined, the iliac artery shunts discontinued and the portal veins joined. Total ischaemic intervals for the allografts were 3 1/2-8 (average 5). Anhepatic intervals were 1-2 1/4 (average 2). The arterio-portal shunts were operating for 18-85 (mean 46) min. Blood loss and haemodynamic, acid-base and electrolyte abnormalities at revascularization were minimal. All grafts secreted bile immediately and all parameters reflected continuing improvement of liver function thereafter. Nine patients (82%) are alive between 4 and 18 (mean 11) months after transplantation. We conclude that these methods offer effective avoidance of serious organ damage during donor hepatectomy and preservation, reduced allograft ischaemic interval and reduced recipient anhepatic time. They result in avoidance of blood loss at the time of revascularization, together with minimal haemodynamic, acid-base or biochemical changes. In addition, they allow the surgeon to perform and test all anastomoses without time constraints, provide the capability to deal with unexpected complications, and assure good early graft function.
Adolescent↗
Australian National Pilot Liver Transplantation Program: the first year's report.
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Actuarial Analysis↗
Time and frequency of recurrence of cutaneous stage I malignant melanoma with guidelines for follow-up study.
This study is based upon 3,171 patients with clinical Stage I cutaneous malignant melanoma treated at the Sydney Melanoma Unit (SMU) in Australia. The mean follow-up period was 9.8 years, ranging from 2.5 to 36.2 years. During the course of this follow-up study, recurrence developed in 886 patients. Three factors that predicted both the risk of recurrence and the disease-free interval were determined. These were thickness of tumor, the first definitive surgical treatment (whether or not the patient underwent elective dissection of lymph nodes) and the ulcerative state of the primary tumor. Follow-up schedules were designed taking all three of the factors into consideration. The schedules so derived reflected both the risk of recurrence and its alteration with time. It will obviously be necessary, however, to modify the frequency of follow-up visits according to the institutional resources available and the specific wishes of the patient. Annual review for an indefinite period for all patients with melanoma is recommended to detect both additional cancers and late recurrences.
Follow-Up Studies↗
Initial report of the Australian National Pilot Liver Transplantation Programme.
Our group began a National Pilot Liver Transplantation Programme in January, 1986, for which this report documents the results of the first 15 months' work. Seventy potential recipients (55 adults, 15 children) were referred for consideration for liver transplantation either directly or by state selection committees that had been established in most Australian states. The most common conditions for referral of adults were chronic active hepatitis, primary sclerosing cholangitis and primary biliary cirrhosis; 11 patients had fulminant hepatic failure. In children, the most common condition for referral was biliary atresia. Twenty-nine (41%) patients were considered unsuitable candidates for liver transplantation, 25 patients (21 adults and four children) were accepted for transplantation at a later time, and 16 patients (11 adults and five children) were selected for immediate transplantation. Of these 16 patients, three patients died before a donor could be found. Of the 13 patients to receive transplants (one patient received two transplants), 10 patients (seven of nine adults; three of four children) are alive and well; nine patients have good liver function and one patient has impaired liver function. The additional costs of the Programme to the hospitals were estimated at approximately $2 million a year. It is concluded that for those persons who require liver transplantation in Australia, worthwhile survival after this procedure can be obtained.
Adolescent↗
Cellular factors couple recombination with growth phase: characterization of a new component in the lambda site-specific recombination pathway.
Here we characterize FIS (factor for inversion stimulation), a new cellular component of the lambda site-specific recombination pathway. This host protein binds to a specific region in the lambda attP overlapping the Xis binding sites and can bind cooperatively with Xis to these sites. FIS stimulates lambda excision up to 20-fold in vitro in the presence of suboptimal Xis concentrations, but has no effect in the presence of saturating Xis; FIS has no effect on integrative recombination. FIS can replace one Xis molecule in a series of cooperative and competitive interactions but cannot carry out excision in the absence of Xis. FIS's role in the regulation of recombination has been inferred from in vivo modification of DNA. In exponentially growing cells the lambda FIS site is fully occupied, whereas in stationary-phase cells this binding site is vacant.
Bacteriophage lambda↗
Protein-protein interactions in a higher-order structure direct lambda site-specific recombination.
The highly directional site-specific recombination of bacteriophage lambda is tightly regulated by the binding of three different proteins to a complex array of sites. The manner in which these reactions are both stimulated and inhibited by co-operative binding of proteins to specific sites on the P arm of attP and AttR has been elucidated by correlation of nuclease protection with recombination studies of both wild-type and mutant DNAs. In addition to co-operative forces, there is a specific competitive interaction that allows the protein-DNA complex to serve as a "biological switch". This switch does not depend upon the simple occlusion of DNA binding sites by neighboring proteins; but, rather, the outcome of this competition is dependent on long-range interactions that vary between the higher-order structures of attP and attR. These higher-order structures are dependent on cooperative interactions involving three proteins binding to five or more sites.
Allosteric Site↗
Cyclosporin conversion versus conventional immunosuppression: long-term follow-up and histological evaluation.
129 patients who received a cadaver renal transplant entered a randomised prospective trial of cyclosporin for 3 months with conversion to azathioprine and prednisolone compared with conventional therapy of azathioprine and prednisolone. In the 64 patients who received cyclosporin, actuarial patient survival was 92%, and actuarial graft survival was 72% and 67% at 1 and 4 years after transplantation. Graft survival was significantly better (p less than 0.03) than in the 65 patients who received conventional therapy, in whom actuarial patient survival was 94%, and actuarial graft survival was 59% and 47% at 1 and 4 years. Renal function and other side-effects improved quickly after conversion with the better renal function maintained throughout follow-up. Renal biopsies at 90 days and 1 year in all patients did not show consistent improvement after conversion from cyclosporin in the histological features that might be attributable to cyclosporin toxicity. After conversion, 32% of the patients had acute rejection, generally within 30 days. 1 graft was lost to early acute rejection after conversion and another was lost 3 months later from acute-on-chronic rejection. A total of 8 grafts were lost to chronic rejection in the cyclosporin-treated group and 6 in the conventional group. The improvement in renal function obtained with this protocol of short-term cyclosporin with conversion to azathioprine and prednisolone has to be balanced against the risk of acute rejection and even loss of the graft after conversion.
Administration, Oral↗
The influence of HLA-A,B and -DR matching on leucocyte infiltration in renal allografts.
The influence of donor and recipient HLA-A,B and -DR matching on the cellular infiltration in renal allografts was examined in 78 transplant recipients who received either cyclosporin (Cy) or azathioprine and low-dose prednisolone (AP) immunosuppression. Transplant biopsies (n = 161) were routinely obtained up to 40 days after transplantation, and biopsy material was therefore available from both rejecting grafts and grafts with stable function. Tissue sections were labelled with a panel of monoclonal antibodies and stained using an indirect immunoperoxidase technique. Cellular infiltration was assessed using a morphometric point counting technique. In AP-treated patients with well-functioning grafts, poor HLA-AB and HLA-DR matching was associated with increased leucocyte infiltration, while in patients receiving Cy therapy the effect of matching on cellular infiltration was seen only during rejection in grafts poorly matched for HLA-AB antigens. In addition, where an effect of HLA-AB matching on cellular infiltration was found, CD8+, but not CD4+ cells, were significantly increased in number, while when an HLA-DR matching effect was seen, a significant increase was observed in the CD4+ and not the CD8+ infiltration. Thus, HLA matching may influence the magnitude of the cellular response in renal allografts and the phenotype of the infiltrating cells.
Azathioprine↗
Morphometric analysis of cellular infiltration assessed by monoclonal antibody labeling in sequential human renal allograft biopsies.
The mononuclear cell infiltrate in a total of 279 human renal allograft biopsies was determined by a panel of monoclonal antibodies using an indirect immunoperoxidase technique. Two hundred and seventy-two biopsies were obtained from 83 patients randomly allocated to receive short-term cyclosporine (CsA) or conventional azathioprine and low-dose prednisolone (AP). Biopsies were obtained routinely at days 0 (control biopsies), 7, 21, 90, and 365, as well as at other times when clinically indicated. A further 7 patients on AP therapy were biopsied several years after transplantation (median: 6 years 1 month). Morphometric analysis of cryostat tissue sections using a point-counting technique has shown that the infiltration in rejecting grafts is significantly greater than in grafts with stable function. However, significant infiltration also occurs within the first week after transplantation in grafts with stable function. While this infiltrate diminishes with time, it remains significant even in grafts biopsied several years after transplantation. The infiltration with CsA treatment is significantly less than with AP therapy. The magnitude of the infiltrate therefore varies with time, graft status, and immunosuppression. In contrast the phenotypic composition of the infiltrate remains relatively constant in all biopsies after transplantation with T lymphocytes (CD3+), accounting for approximately 35% of infiltrating cells and CD8+ cells more common than CD4+. Monocytes and macrophages account for most of the remainder of the infiltrate.
Antibodies, Monoclonal↗
Studies on the Mechanism of Regulation of the mRNA Level for a Soybean Storage Protein Subunit by Exogenous l-Methionine.
In previous studies (GL Creason et al. 1983 Biochem Biophys Res Commun 117: 658-662; LP Holowach et al. 1984 Plant Physiol 74: 576-583), we have shown that when soybean (Glycine max L. Merrill cv Provar) cotyledons are cultured in medium supplemented with l-methionine, the beta-subunit of 7S protein and beta-mRNA are absent. We have carried out further studies on the mechanism of the methionine action. In one experiment, cotyledons were cultured for 16 days with or without methionine. After 4 days, some cotyledons were transferred from methionine-supplemented to basal (no methionine) medium and vice versa. In basal medium, beta-subunit was detected at 4 days whereas in methionine-supplemented medium, no beta-subunit was present. When cotyledons were transferred from basal to methionine-supplemented medium, the beta-subunit increased within a 4 day period and then remained constant (on a per cotyledon basis). This result indicated that methionine was not acting by accelerating the degradation of the beta-subunit. Four days after transfer from supplemented to basal medium cotyledons contained beta-subunit, thus demonstrating that the inhibition was reversible. During this time, the uncombined methionine declined from 7 to 1.5 mumoles methionine per gram fresh weight. When beta-mRNA was measured by in vitro translation, functional beta-mRNA was absent in tissue that was not accumulating beta-subunit. The messenger RNA for the beta-subunit had a half-life of about 1 day in the presence of methionine. Hybridization of cotyledon mRNA with cDNA complementary to beta-mRNA revealed that the 1700 nucleotide beta-mRNA was not present in supplemented cotyledons. Thus, expression of the beta-subunit gene is controlled at the level of transcription, RNA processing, or RNA turnover, rather than at the level of translation.
Journal Article↗
The lipoxygenases in developing soybean seeds, their characterization and synthesis in vitro.
A number of lipoxygenase isoenzymes were identified in developing soybean (Glycine max L. Merrill cv Provar) seeds and two have been partially characterized. In a study of lipoxygenase level in developing soybean seeds, the enzyme content increased markedly during development. Comparisons of the lipoxygenases from mature soybean seeds and immature seeds by isoelectric focusing, chromatofocusing, sodium dodecyl sulfate polyacrylamide gel electrophoresis and peptide mapping identified two categories of isoenzyme. The isoenzymes from immature seeds were found by electron paramagnetic resonance spectroscopy to be isolated at least in part as the high spin iron(III) or active form of the enzyme in contrast to lipoxygenases from mature seeds which were isolated as electron paramagnetic resonance silent, high spin iron(II) species. The discovery of increased levels of lipoxygenases during seed development and their isolation in an active form suggests that the enzyme may play a physiological role during the maturation process. The incorporation of iron-59 from the nutrient medium into lipoxygenase during culture of immature seeds was indicative of de novo synthesis of the enzyme. The efficiency of the iron uptake was high, as indicated by the level of radioactivity found in the enzyme (one gram atom of iron per mole of lipoxygenase).
Journal Article↗
Mutations in an integration host factor-binding site: effect on lambda site-specific recombination and regulatory implications.
The manner in which integration host factor (IHF) regulates lambda site-specific recombination has been analyzed by examining the behavior of both wild-type and mutant DNAs in integrative and excisive recombination as well as in protein binding. While integrative recombination of an attP with two base changes in the H1 site required 8-fold more IHF than did wild type, binding to this site was lowered at least 500-fold, suggestive of cooperative interactions. A mutant attP with nine base changes did not integrate at all in vitro, with the defect being less severe in vivo. IHF inhibition of excisive recombination was relieved by both mutations in vitro and in vivo. These results imply that occupancy of the H1 site is critical for determining the direction of recombination. It is proposed that IHF inhibition of excision provides a monitor of the strength of the induction stimulus and the nutritional state of the cell; this would allow the prophage to excise selectively in conditions which favor successful completion of the lytic cycle.
Bacterial Proteins↗