Search PubMed⌕ Search

Biomedical subjects

J Wilkinson

Publications and source records attributed to J Wilkinson.

At least 37 records · Page 2Linked to original sources
PubMed2001

Changes in hepatitis C virus population in serum and peripheral blood mononuclear cells in chronically infected patients receiving liver graft from infected donors.

BACKGROUND: We have previously studied hepatitis C (HCV)-infected recipients of livers from HCV-infected donors and found that either the donor's strain or the recipient's strain predominate in serum. The current study was undertaken to determine whether these changes are complete and whether they are reflected in the population of virus associated with peripheral blood mononuclear cells (PBMCs). METHODS: We analyzed HCV ribonucleic acid from sequential serum and PBMC samples from 11 and 8 patients, respectively. The relatively stable NS5 region was chosen for analysis because it allowed for dependable identification of donor and recipient strains. Viral sequences were analyzed by direct sequencing and by sensitive strain-specific polymerase chain reaction assays. These assays were capable of detecting the minor sequence present at a concentration 1:104-10-7 below that of the major sequence. RESULTS: Five patients retained their original infecting strain; the donor strain was detected only transiently. In the remaining six patients, recipient strain was detected for the first few weeks, after which only the donor strain was consistently present. However, in one patient the second nondominant strain was detected from the background of the major strain on a single occasion 8 months after transplantation. All changes in serum were closely paralleled by those occurring in PBMCs. CONCLUSIONS: Viral population changes in the setting of liver transplantation from HCV-infected donors to HCV-infected recipients occur simultaneously in PBMCs and serum. The takeover of one strain by another in PBMC- and serum-derived viral populations seemed to be complete and long lasting.

Base Sequence↗
PubMed2001

A role for smooth endoplasmic reticulum membrane cholesterol ester in determining the intracellular location and regulation of sterol-regulatory-element-binding protein-2.

Cellular cholesterol homoeostasis is regulated through proteolysis of the membrane-bound precursor sterol-regulatory-element-binding protein (SREBP) that releases the mature transcription factor form, which regulates gene expression. Our aim was to identify the nature and intracellular site of the putative sterol-regulatory pool which regulates SREBP proteolysis in hamster liver. Cholesterol metabolism was modulated by feeding hamsters control chow, or a cholesterol-enriched diet, or by treatment with simvastatin or with the oral acyl-CoA:cholesterol acyltransferase inhibitor C1-1011 plus cholesterol. The effects of the different treatments on SREBP activation were confirmed by determination of the mRNAs for the low-density lipoprotein receptor and hydroxymethylglutaryl-CoA (HMG-CoA) reductase and by measurement of HMG-CoA reductase activity. The endoplasmic reticulum was isolated from livers and separated into subfractions by centrifugation in self-generating iodixanol gradients. Immunodetectable SREBP-2 accumulated in the smooth endoplasmic reticulum of cholesterol-fed animals. Cholesterol ester levels of the smooth endoplasmic reticulum membrane (but not the cholesterol levels) increased after cholesterol feeding and fell after treatment with simvastatin or C1-1011. The results suggest that an increased cellular cholesterol load causes accumulation of SREBP-2 in the smooth endoplasmic reticulum and, therefore, that membrane cholesterol ester may be one signal allowing exit of the SREBP-2/SREBP-cleavage-regulating protein complex to the Golgi.

Acetamides↗
PubMed2001

Exposure of hepatitis C virus-negative recipients to > or =2 infected blood donors.

This study analyzed 4 cases of hepatitis C virus (HCV)-naive transfusion recipients who developed hepatitis after receiving blood from >1 HCV-infected donor. One recipient was exposed to 4 donors, 2 were exposed to 3 donors, and 1 was exposed to 2 donors. For 3 recipients, the strain from 1 of the donors predominated in all follow-up samples collected for 8-40 months. For 2 recipients, the strain from the second donor was occasionally detectable with sensitive strain-specific assays. For the fourth recipient, the initially dominant strain was later supplanted by a strain from the other donor. Simultaneous exposure to multiple HCV strains may result in concomitant infection by >1 strain, although a single strain rapidly establishes its dominance. These observations are compatible with the presence of competition among infecting HCV strains that results in the dominance of 1 strain and competitive exclusion or suppression of other strains.

Adult↗
PubMed2001

Female control of sexuality: illusion or reality? Use of vaginal products in south west Uganda.

This paper reports on a trial of vaginal products that were distributed and used by 131 women and 21 men in south west Uganda. It focuses specifically upon the issue of female control in heterosexual relationships and examines whether methods which are ostensibly under women's control, will in practice give women greater control of their sexual health. Participants were invited to select two from a range of vaginal products that included the female condom, contraceptive sponge, film, tablets, foam and gel, and use each for five weeks and their favourite product for a further three months. They were interviewed up to seven times over a five-month period. Although the women perceived that a major advantage of the products (with the exception of the female condom) was that they could be used secretly, less than 40% were using the products without their partner's knowledge after one week and this proportion declined over time with only 22% using the products secretly after ten weeks. In the main male partners were told as women felt it their duty to inform them. In general the women were very much more positive about the products than they were about the male condom, as were the men. A contributory factor to their popularity among women was the greater control they gave them. Even though, use of these products in practice often involved negotiation with male partners, the fact that use was contingent on women's action was empowering and increased somewhat their ability to control their sexual health.

Adolescent↗
PubMed2001

Effect of overexpression of fatty acid 9-hydroperoxide lyase in tomatoes (Lycopersicon esculentum Mill.).

To modify the flavor properties of tomato fruits, cucumber fatty acid hydroperoxide lyase (HPL), which can act on 9-hydroperoxides of fatty acids to form volatile C9-aldehydes, was introduced to tomato plants. Through enzyme assay, high activity of the introduced HPL could be found in either the leaves or fruits of transgenic tomatoes; however, the composition of volatile short-chain aldehydes and alcohols in the transgenic tomato fruits was little modified. This was unexpected because tomato fruits have high lipoxygenase activity to form 9-hydroperoxides. When linoleic acid was added to a crude homogenate prepared from the transgenic tomato fruits, a high amount of C9-aldehyde was formed, but the amount of C6-aldehyde was almost equivalent to that in nontransgenic tomatoes. Through quantification of fatty acid hydroperoxides, it has been revealed that 13-hydroperoxides of fatty acids are preferably formed from endogenous substrate, whereas 9-hydroperoxides are formed from fatty acids added exogenously. From these observations, possible mechanisms to regulate metabolic flow of the lyase pathway are discussed.

Aldehydes↗
PubMed2001

Fragrance contact dermatitis: a worldwide multicenter investigation (Part II).

The purpose of this study was to determine the frequency of responses to selected fragrance materials in patients who were fragrance sensitive. 178 patients were evaluated in 8 centers worldwide with a fragrance mix (FM) and 20 other fragrance materials. Reaction to the fragrance mixture (FM) occurred in 78.7% of the subjects. Substances reacting at a rate of 2% or higher included jasmine absolute, geranium oil bourbon, l-citronellol, spearmint oil, 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-gamma-2-benzopyran, omega-6-hexadecenlactone, dimethyltetrahydrobenzaldehyde (isomer mixture), and alpha-amylcinnamaldehyde. These chemicals should be furthur evaluated to corroborate their allergenicity. We are constantly looking for new fragrance allergens to extend the diagnostic capability of the fragrance mix (FM).

Allergens↗
PubMed2001

Linkage analysis of the 5q31-33 candidate region for asthma in 240 UK families.

Atopy and asthma are complex genetic diseases resulting from the interactions of a number of genetic and environmental factors. We had previously reported allelic association between the IL9 marker on chromosome 5q31-33 and atopy. In order to further investigate the role of susceptibility genes on 5q31-33 in the development of atopy and asthma we have studied 240 UK families comprising 131 families selected at random, 60 multiplex families with affected sib pairs, and 49 single proband nuclear families. Polymorphic markers on 5q31-33 were genotyped and both single and multipoint linkage analysis was undertaken using the BETA program. We have used both affection status and quantitative scores for atopy and asthma for phenotypic variables, combining data into scores for asthma and atopy. The strongest suggestion of linkage using multipoint analysis was centred around D5S410 with a maximum Lod of 1.946 at location 171.3 cM and a standard error of 3.3 for the asthma quantitative score. There was no evidence of linkage with atopy, the atopy quantitative score or total serum IgE.

Asthma↗
PubMed2001

Administration of blood transfusions to adults in general hospital settings: a review of the literature.

The Serious Hazards of Transfusion (SHOT) haemovigilance scheme for the United Kingdom and Republic of Ireland has clearly indicated that there are avoidable risks to which recipients of blood transfusion are exposed. Sometimes errors in practice have led to serious and even fatal consequences, particularly when a haemolytic response occurs due to an incompatible transfusion. Despite the risks, blood transfusion is an important and frequently life-saving therapy and its use in clinical practice is common. This paper discusses recently published national guidelines for the care of recipients of blood transfusion in the light of a review of the literature relevant to the administration of blood transfusions to adults in general hospital settings. Recommendations for practitioners, managers and teachers are offered in relation to preventing errors and to patient care associated with blood transfusion in the context of contemporary emphasis upon evidence based care.

Adult↗
PubMed2001

National audit of the blood transfusion process in the UK.

The objectives of this initiative were to produce nationally tested audit tools, to influence the content of national guidelines, and to enable performance indicators to be set for the clinical transfusion process. Audit tools were developed for blood transfusion practice through a collaboration between Royal Colleges and specialist Societies with an interest in blood transfusion. National audits were carried out involving 50 hospitals in the first audit and 23 of the same hospitals in the second. Over 20% of participating hospitals did not have Hospital Transfusion Committees. Most hospitals had written policies for the taking of blood samples for grouping and compatibility testing. Formal training for the phlebotomists and nurses who took blood samples was almost universal, but only one-third gave training to doctors. The audits of transfusion practice demonstrated considerable variation in the performance of standard procedures in relation to the administration of blood, and little change in practice between the two audits. The first two objectives have been met in that audit tools were developed and published, and information from the first audits was used in the development of national guidelines for the administration of blood. A significant shortfall in the systems for monitoring and delivering transfusions is present in many hospitals. This justifies pursuing the third objective but this will require a new initiative. The type of analysis and the method used for the presentation of audit data developed in this study may be useful for setting performance indicators for the clinical transfusion process.

Blood Transfusion↗
PubMed2001

Successful treatment of perianal warts in a child with 5% imiquimod cream.

Treatment of anogenital warts in children is difficult. Commonly used therapeutic regimes can be painful, variably effective and recurrence rates are high. Imiquimod is a recently developed imidazoquinolin heterocyclic amine that is an immune response modifier. Topical imiquimod has been used successfully to treat anogenital warts in adults. This case documents the effective use of topical imiquimod in the treatment of perianal warts in children.

Adjuvants, Immunologic↗
PubMed2001

Immune interventions.

A better understanding of the immune response to HIV and the deleterious effect that HIV infection may have on the immune system in general, allows us to consider how best to restore protective immune responses to HIV and other opportunistic pathogens in the immunocompromised host. In this chapter, we summarise areas of current innovation and provide an update of the current state of knowledge concerning interventions which could result in the immunocompromised state being reversed. We describe the kinds of immune responses, which are thought to be useful in combating both the human immunodeficiency virus and other pathogenic organisms, and methods which are being considered to stimulate such responses. Lessons which may be learned from other disease states, which lead to immunodeficiency and methods for measuring successful outcome of treatment will be described.

AIDS Vaccines↗
PubMed2001

Exposure of hepatitis C virus (HCV) RNA-positive recipients to HCV RNA-positive blood donors results in rapid predominance of a single donor strain and exclusion and/or suppression of the recipient strain.

We have analyzed three cases of hepatitis C virus (HCV)-infected recipients who received blood from HCV-infected donors. Two recipients were exposed to two different HCV RNA-positive donors, and one was exposed to a single donor. All parental genomes from the actual infecting units of blood and the recipients were defined, and their presence in the follow-up serum samples was determined using sensitive strain-specific assays. The strain from one of the donors was found to predominate in all recipients' serum samples collected throughout the follow-up period of 10 to 30 months. In two recipients exposed to two infected donors, the strain from the second donor was occasionally found at very low level. However, the original recipients' strains were not detected. Our observations show that HCV-infected individuals can be superinfected with different strains, and this event may lead to eradication or suppression of the original infecting strain. Furthermore, our findings demonstrate that simultaneous exposure to multiple HCV strains may result in concomitant infection by more than one strain, although a single strain could rapidly establish its dominance. The results of the present study suggest the existence of competition among infecting HCV strains which determines the ultimate outcome of multiple HCV exposure.

Adult↗
PubMed2001

Breast cancer and human immunodeficiency virus: a report of 20 cases.

Carcinoma of the breast is the most common malignancy in women in the United States. More than 40% of patients with human immunodeficiency virus (HIV) infection develop cancer during their illness, but breast cancer has seldom been reported. Twenty patients with breast cancer and HIV infection seen at the University of Miami/Jackson Memorial Hospital between January 1988 and August 2000 were retrospectively analyzed. Seventeen patients had a previous or concurrent diagnosis of HIV at the time of the breast cancer diagnosis. Their CD4 count ranged from 13-1126/microL (median, 309/microL). Most patients were premenopausal (16 of 20), with ages ranging from 31-61 years (median, 44 years). All stages of breast cancer were seen: ductal carcinoma in situ (2 patients), stage I (1 patient), stage II (9 patients), stage III (6 patients), and stage IV (2 patients). Ten tumors had estrogen receptors. Four of the 13 patients who underwent axillary lymph node dissection had abnormal lymph node findings, including 2 with follicular hyperplasia and 2 with caseating granulomas. Seven patients received chemotherapy with very poor tolerance. Estrogen receptor-positive patients were treated with tamoxifen. Of the 18 patients who presented with local disease, 7 have died: 2 of breast cancer, 4 of acquired immunodeficiency syndrome, and 1 of cardiac arrest. Nine patients remain free of disease (5 of them > 5 years) and 2 patients are alive with metastatic disease. Breast cancer in the HIV-positive population is similar to that seen in seronegative women. Most of the patients that are long-term survivors were treated with surgery and tamoxifen. The benefits of adjuvant chemotherapy are not clear.

Adult↗
PubMed2001

Enhanced levels of the aroma and flavor compound S-linalool by metabolic engineering of the terpenoid pathway in tomato fruits.

The aromas of fruits, vegetables, and flowers are mixtures of volatile metabolites, often present in parts per billion levels or less. We show here that tomato (Lycopersicon esculentum Mill.) plants transgenic for a heterologous Clarkia breweri S-linalool synthase (LIS) gene, under the control of the tomato late-ripening-specific E8 promoter, synthesize and accumulate S-linalool and 8-hydroxylinalool in ripening fruits. Apart from the difference in volatiles, no other phenotypic alterations were noted, including the levels of other terpenoids such as gamma- and alpha-tocopherols, lycopene, beta-carotene, and lutein. Our studies indicate that it is possible to enhance the levels of monoterpenes in ripening fruits by metabolic engineering.

Acyclic Monoterpenes↗
PubMed2000

Fatty acid 9- and 13-hydroperoxide lyases from cucumber.

Fatty acid hydroperoxide lyase (HPL) is a novel P-450 enzyme that cleaves fatty acid hydroperoxides to form short-chain aldehydes and oxo-acids. In cucumber seedlings, the activities of both fatty acid 9HPL and 13HPL could be detected. High 9HPL activity was especially evident in hypocotyls. Using a polymerase chain reaction-based cloning strategy, we isolated two HPL-related cDNAs from cucumber hypocotyls. One of them, C17, had a frameshift and it was apparently expressed from a pseudogene. After repairing the frameshift, the cDNA was successfully expressed in Escherichia coli as an active HPL with specificity for 13-hydroperoxides. The other clone, C15, showed higher sequence similarity to allene oxide synthase (AOS). This cDNA was also expressed in E. coli, and the recombinant enzyme was shown to act both on 9- and 13-hydroperoxides, with a preference for the former. By extensive product analyses, it was determined that the recombinant C15 enzyme has only HPL activity and no AOS activity, in spite of its higher sequence similarity to AOS.

Aldehyde-Lyases↗