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Biomedical subjects

J Wilson

Publications and source records attributed to J Wilson.

At least 199 records · Page 11Linked to original sources
PubMed1999

Pre-transplant immunological profile and risk factor analysis of post-transplant lymphoproliferative disease development: the results of a nested matched case-control study. The University of Pittsburgh PTLD Study Group.

Development of post-transplant lymphoproliferative disease (PTLD) is a major complication of organ transplantation. While immune mechanisms seem to play a major role in the development of PTLD, how the immune system contributes to the process of PTLD development or its regression remains unknown. Between 1990-1994, 303 organ transplant recipients were enrolled into a prospective study designed to analyze risk factors for PTLD. Using a nested case-control design, 9 PTLD and 18 control patients were matched for age, EBV serological status at the time of transplantation, and, in most cases, for the type of transplanted organ. The immunologic profiles of both groups were compared prior to and following transplantation. Immune measures included absolute numbers of lymphocytes and of subsets of T, B and natural-killer (NK) cells as well as spontaneous NK-cell and in vitro generated LAK-cell activities. A consistent trend for higher levels at baseline as well as following transplantation for almost all immune parameters was observed in patients who developed PTLD. A high absolute count of activated NK cells (CD56+ DR+) at baseline was found to be a significant predictor of PTLD development. The immunologic profile of patients who developed PTLD was consistent with pre- as well as post-transplant chronic immunologic stimulation, and not immunosuppression. In the PTLD group, 3 patients had pre-transplant autoimmune hepatitis and one had primary biliary cirrhosis, which suggests that the underlying presence of certain autoimmune disorders in organ transplant recipients might predispose to PTLD development.

Adult↗
PubMed1999

The treatment of ambulatory venous ulcer patients with warming therapy.

The standard treatment for ambulatory patients with venous ulcers is compression therapy. The aim of the present study was to develop a warming regimen to treat venous ulcers, which could be easily used by patients in their home or work environment. Five patients with a mean age of 66 years (51-80) who had venous ulcers for an average of 8 months (3-13) were treated with zip-up compression stockings (gradient compression 40 mmHg at the ankle) and a warming dressing. The latter was controlled by the patient to warm the ulcer to 38 degrees C for 1 hour three times daily. Warming therapy was carried out for 2 weeks and patients' ulcers were monitored for healing for 12 weeks. In all but one of the patients following warming therapy, there was marked increase in granulation tissue as well as a decrease in pain. Four of the five patients completely healed during the 12-week period. In conclusion, this study has demonstrated that warming therapy can be used by ambulatory patients with venous ulcers in conjunction with compression therapy. A randomized prospective study is in progress.

Aged↗
PubMed1998

Use of soybean oil and ammonium sulfate additions to optimize secondary metabolite production.

A valine-overproducing mutant (MA7040, Streptomyces hygroscopicus) was found to produce 1.5 to 2.0 g/L of the immunoregulant, L-683,590, at the 0.6 m3 fermentation scale in a simple batch process using soybean oil and ammonium sulfate-based GYG5 medium. Levels of both lower (L-683,795) and higher (HH1 and HH2) undesirable homolog levels were controlled adequately. This batch process was utilized to produce broth economically at the 19 m3 fermentation scale. Material of acceptable purity was obtained without the multiple pure crystallizations previously required for an earlier culture, MA6678, requiring valine supplementation for impurity control. Investigations at the 0.6 m3 fermentation scale were conducted, varying agitation, pH, initial soybean oil/ammonium sulfate charges, and initial aeration rate to further improve growth and productivity. Mid-cycle ammonia levels and lipase activity appeared to have an important role. Using mid-cycle soybean oil additions, a titer of 2.3 g/L of L-683,590 was obtained, while titers reached 2.7 g/L using mid-cycle soybean oil and ammonium sulfate additions. Both higher and lower homolog levels remained acceptable during this fed-batch process. Optimal timing of mid-cycle oil and ammonium sulfate additions was considered a critical factor to further titer improvements.

Ammonium Sulfate↗
PubMed1998

The comparative effects of the NOS inhibitor, Nomega-nitro-L-arginine, and the haemoxygenase inhibitor, zinc protoporphyrin IX, on tumour blood flow.

PURPOSE: To determine the relative effects of inhibiting nitric oxide synthase (NOS) and haemoxygenase (HO) on blood flow to the rat P22 carcinosarcoma. METHODS AND MATERIALS: HO is the enzyme responsible for in vivo production of carbon monoxide (CO). The vascular effects of zinc protoporphyrin IX (ZnPP), a competitive inhibitor of HO, were compared with those of copper protoporphyrin IX (CuPP), a poor inhibitor of HO, in isolated ex vivo perfusions of the P22 tumour and in intact tumour-bearing rats. In ex vivo perfusions, tumour vascular resistance was calculated from measurements of perfusion pressure at a known flow rate. In intact animals, blood flow to tumour and normal tissues was calculated using a radiotracer uptake method. The effects of ZnPP were compared with those of the NOS inhibitor, N(omega)-nitro-L-arginine (L-NNA), and the combination of the two drugs. RESULTS: HO activity in the P22 tumour was reduced by 50% following administration of either ZnPP or CuPP directly to ex vivo perfused tumours, suggesting an indirect effect on the enzyme. Enzyme inhibition was not associated with any significant vasoactive effect. Neither ZnPP nor CuPP, at a dose of 45 micromol x kg(-1) administered i.p., inhibited tumour HO in vivo. However, they did significantly decrease tumour blood flow to 60-70% of control, with similar effects in skin and brain. Skeletal muscle blood flow was increased to 150% of control. L-NNA decreased both tumour and skeletal muscle blood flow to around 40% of control. These differences suggest that the nonspecific effects of ZnPP and CuPP were not mediated by NOS inhibition. The combination of ZnPP and L-NNA improved the selective reduction in tumour blood flow achieved with either agent alone. CONCLUSION: This suggests that the HO/CO pathway does not play a major vasodilatory role in this tumour. However, ZnPP and CuPP could be useful for inducing a relatively selective decrease in tumour blood flow via mechanisms unrelated to HO inhibition, especially when combined with NOS inhibition.

Animals↗
PubMed1998

The aetiology, diagnosis and management of denture stomatitis.

This article examines the evidence for the aetiology, diagnosis and management of denture stomatitis. Extensive reviews of the literature using the Index to Dental Literature, references in relevant publications and computerised databases were employed. Microbiological confirmation of implicated Candida infection should be sought before prescribing antifungal drugs.

Antifungal Agents↗
PubMed1998

Methionine formation from alpha-ketomethiobutyrate in the trypanosomatid Crithidia fasciculata.

Methionine consumed during the synthesis of polyamines can be recycled in most organisms by a unique pathway wherein the final step is the transaminative conversion of alpha-ketomethiobutyrate to methionine (KMAT activity). In the trypanosomatid Crithidia fasciculata, three separate aminotransferases (KMAT-A, -B, -T) were found to catalyse this activity. All three aminotransferases were found to utilise aromatic amino acids as the amino donor for the KMAT reaction, but KMAT-A functioned optimally with histidine and KMAT-B with arginine as amino donors. KMAT-T was found to operate best with aromatic amino acids and glutamate as amino donors, and was also found to catalyse aspartate aminotransferase and tyrosine aminotransferase activities. Amino acid sequencing of internal peptides from KMAT-T yielded a sequence with very high identity to vertebrate, cytosolic aspartate aminotransferase. As pig heart cytosolic aspartate and alanine aminotransferases were found to be unable to catalyse KMAT activity, the crithidial enzyme appears to be an aspartate aminotransferase with unusual catalytic properties. Inhibition studies on C. fasciculata homogenates showed that carboxymethoxylamine, canaline, and nitrophenylalanine were effective inhibitors of total KMAT activity (63-100% inhibition at 1 mM in the presence of 1 mM alpha-ketomethiobutyrate and 30 mM total amino acid as substrates) and the individual, isolated enzymes. At 1 mg ml-1, canaline was found to inhibit cell growth in vitro by 62%, and carboxymethoxylamine caused cell death within 24 h.

Alanine↗
PubMed1998

The ihf mRNA levels decline as Neisseria gonorrhoeae enters the stationary growth phase.

Integration host factor (IHF) is a small heterodimeric DNA binding protein found in all Gram-negative bacteria and is implicated as a transcription cofactor of pilE in Neisseria gonorrhoeae (Hill, S.A., Samuels, D.S., Carlson, J.H., Wilson, J., Hogan, D., Lubke, L., Belland, R.J., 1997. Integration host factor is a transcriptional cofactor of pilE in Neisseria gonorrhoeae. Mol. Microbiol. 23, 649-656). The ihf genes (ihfA and ihfB) were cloned from N. gonorrhoeae through functional complementation of defined Escherichia coli ihf mutants for plating of phage lambda. The predicted aa sequences of each gonococcal IHF polypeptide showed extensive homology to other reported IHF polypeptide sequences. Northern blotting and primer extension analysis defined the tsp for each gene and indicated a disparity in ihfA and ihfB message levels over time, with ihfB mRNA being more abundant throughout the entire growth cycle. Furthermore, both the ihfA and ihfB message levels declined as cells entered the stationary growth phase. Overall, this study reveals several unique features of ihf transcription in the gonococcus which questions whether certain aspects if ihf transcriptional regulation are universally shared by all Gram-negative bacteria.

Amino Acid Sequence↗
PubMed1998

Principles for Sustainable Governance of the Oceans

Pressures being exerted on the ocean ecosystems through overfishing, pollution, and environmental and climate change are increasing. Six core principles are proposed to guide governance and use of ocean resources and to promote sustainability. Examples of governance structures that embody these principles are given.

Journal Article↗
PubMed1998

Clinical significance of viral load in the diagnosis of cytomegalovirus disease after liver transplantation.

In a cohort of 43 liver transplant recipients who did not receive antiviral prophylaxis, qualitative and quantitative polymerase chain reactions (PCRs) from peripheral blood were prospectively compared to determine their value in the diagnosis of established cytomegalovirus (CMV) disease and for the early detection of CMV replication as a marker for preemptive antiviral therapy. Using a cutoff of 7000 copies of CMV DNA per sample, the specificity and positive predictive values of qualitative PCR for the diagnosis of established CMV disease increased from 33% to 89% and from 54% to 82%, respectively, without reducing the 100% sensitivity and negative predictive value. By contrast, quantification of viral load provided no additional advantage to qualitative PCR for the early diagnosis of CMV infection before development of disease.

Blood↗
PubMed1998

The effect of ethanol on pancreatic enzymes--a dietary artefact?

The effects of ethanol on pancreatic digestive and lysosomal enzymes may be relevant to the pathogenesis of alcoholic pancreatitis since pancreatic enzymes are thought to play an important role in the development of pancreatic injury. Previous studies, using the Lieber-DeCarli pair-feeding model of ethanol administration, have demonstrated that ethanol significantly increases the content and gene expression of pancreatic enzymes. However, these findings have been questioned because, in the Lieber-DeCarli model, ethanol-fed rats have a lower carbohydrate intake than their pair-fed controls, making it difficult to ascribe any observed changes to ethanol alone. This study was designed to distinguish between the effects of ethanol and those of reduced dietary carbohydrate on pancreatic enzymes, using a quartet-feeding model of ethanol administration. Rats were fed liquid diets containing low (11%) and high (47%) amounts of carbohydrate, with and without ethanol, for four weeks. The effects of ethanol on pancreatic content and messenger RNA levels for digestive enzymes (trypsinogen, chymotrypsinogen and lipase) and a lysosomal enzyme (cathepsin B) were assessed. Ethanol feeding resulted in a significant increase in glandular content with a corresponding increase in mRNA levels for all four enzymes studied. By contrast, a reduction in dietary carbohydrate intake alone did not alter pancreatic content or gene expression for the above enzymes. These results indicate that (i) ethanol significantly increases the capacity of the acinar cells to synthesise digestive enzymes and the lysosomal enzyme cathepsin B, and (ii) these changes are due to ethanol itself and are not due to variations in dietary carbohydrate intake.

Animals↗