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Biomedical subjects

D R Jenkins

Publications and source records attributed to D R Jenkins.

At least 19 recordsLinked to original sources
PubMed2006

Screening strategies in surveillance and control of methicillin-resistant Staphylococcus aureus (MRSA).

With reports of hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) continuing to increase and therapeutic options decrease, infection control methods are of increasing importance. Here we investigate the relationship between surveillance and infection control. Surveillance plays two roles with respect to control: it allows detection of infected/colonized individuals necessary for their removal from the general population, and it allows quantification of control success. We develop a stochastic model of MRSA transmission dynamics exploring the effects of two screening strategies in an epidemic setting: random and on admission. We consider both hospital and community populations and include control and surveillance in a single framework. Random screening was more efficient at hospital surveillance and allowed nosocomial control, which also prevented epidemic behaviour in the community. Therefore, random screening was the more effective control strategy for both the hospital and community populations in this setting. Surveillance strategies have significant impact on both ascertainment of infection prevalence and its control.

Cross Infection↗
PubMed2005

Optimal spacing and penetration of cracks in a shrinking slab.

A method based on energy minimization is used to determine the spacing and penetration of a regular array of cracks in a slab that is shrinking due to a changing temperature field. The results show a range of different crack propagation behavior dependent on a single dimensionless parameter, being the ratio of the slab thickness and a characteristic length for the material. At low parameter values the minimum energy state can be achieved by continually adding more cracks until a steady state is achieved. At higher values, a minimum crack spacing is reached at finite time, beyond which the cracks are constrained to propagate with the minimum spacing. In the latter case, the uniform propagation is potentially unstable to a spatial period doubling, leading to increasingly complex crack penetration patterns. The energy minimization combined with the period doubling instability provides a means of determining the minimum energy state of cracks for all time. The problem considered here can be seen as a paradigm for cracking phenomena that occur on a large range of scales, from planetary to microscopic.

Journal Article↗
PubMed2005

Disseminated Sporothix schenckii in a patient with AIDS.

Sporothrix schenckii is a widespread dimorphic fungus which can cause cutaneous infection following local implantation. Disseminated sporotrichosis may occur in immunodeficient individuals but meningitis remains a rare complication. Diagnosis is usually difficult, requiring isolation of the organism from the CSF or skin so appropriate treatment can be promptly initiated. We present the first case of S. schenckii meningitis reported in the UK in a patient with AIDS. He presented with insidious features of meningoencephalitis, hydrocephalus and multiple cutaneous lesions and failed to respond to therapy.

AIDS-Related Opportunistic Infections↗
PubMed2005

The pharmacokinetics of linezolid in the non-inflamed human eye.

AIM: This study describes the ocular pharmacokinetics of linezolid, an antibiotic with broad spectrum activity against those Gram positive bacteria that are the most frequent cause of postoperative endophthalmitis. METHOD: Patients undergoing routine cataract surgery were given a single oral 600 mg dose of linezolid at a variable time before surgery. Aqueous and serum levels of linezolid were assayed by high performance liquid chromatography, and a pharmacokinetic curve constructed from the pooled results. RESULTS: Orally administered linezolid rapidly achieves levels in the aqueous of non-inflamed eyes that exceed the concentration required to kill Gram positive bacteria (maximum mean concentration 6.8 (SD 1.2) microg/ml at 2-4 hours post-dose). An effective concentration is maintained for at least 12 hours, the standard interdose interval for this antimicrobial. CONCLUSION: Linezolid offers the possibility of a rapid, oral approach to effective treatment of most cases of postoperative endophthalmitis, with the potential of improving visual outcome.

Acetamides↗
PubMed1998

Non-tuberculous mycobacterial infection in children with cancer.

Reported here is the clinical presentation and management of patients with rapidly growing non-tuberculous mycobacterial infection diagnosed in a paediatric oncology unit. A retrospective analysis that correlated patient isolates with the children's cancer registry revealed two cases of non-tuberculous mycobacterial infection; both had been observed within the last 6 years and were due to Mycobacterium chelonae. The first case was line-associated and the second was a disseminated infection. In both cases the patients were lymphopenic and had had indwelling vascular catheters. Neither patient was neutropenic. The literature on mycobacterial infection in children with cancer is also reviewed.

Child, Preschool↗
PubMed1996

A mixed outbreak of cryptosporidium and campylobacter infection associated with a private water supply.

In an outbreak of gastroenteritis affecting 43 people, cryptosporidium and campylobacter were isolated from stool specimens and in two cases dual infection was found. All the cases had drunk unboiled water from a private untreated water supply. Investigations revealed the carcasses of three lambs in a collection chamber connected with the water supply, and these, or run-off of slurry from surrounding fields, were the presumed source of contamination. Issues relating to the maintenance and monitoring of private water supplies are discussed. Problems with such supplies include old piping, proximity of livestock, inadequate knowledge of the layout and limited resources for monitoring and maintenance.

Adult↗
PubMed1995

Sporadic isolates of Escherichia coli O157.H7 investigated by pyrolysis mass spectrometry.

Thirty-six encoded isolates of Escherichia coli. 32 of which were of serotype O157, were examined by pyrolysis mass spectrometry (PyMS). Thirty-one of the serotype O157 isolates possessed the flagellar antigen H7 and produced Verocytotoxin (VT), the other isolate serotyped as H45 and was non-toxigenic. Eighteen of the VT-producing E. coli (VTEC) isolates were from sporadic disease in residents of the Northern Region. Standard principal component (PC) and canonical variate (CV) analysis of the data distinguished only the four non-O157 isolates from the remainder which were indistinguishable by this approach. A similarity matrix based on differences between individual CV means distinguished a further ten isolates. The matrix correctly clustered 2 pairs of isolates from siblings and 4 isolates from an affected family. A further 5 clusters of 3 or more isolates and 6 pairs of isolates were defined. These groupings proved to be homogenous for toxin phenotype but occasionally entrained isolates of dissimilar phage type. However, in general, PyMS-derived clustering of apparently sporadic isolates accorded with geographical locations as determined by postcode. PyMS, which is a quick and high volume capacity phenotypic technique, may be a useful addition to existing methods in the investigation of the epidemiology of sporadic VTEC disease.

Escherichia coli↗
PubMed1992

Immunologic and structural relatedness of the integrin beta 7 complex and the human intraepithelial lymphocyte antigen HML-1.

We recently cloned the newest human integrin beta subunit, termed beta 7, from a cDNA library constructed from SEA-activated T lymphocytes. In this communication, we report on the structure of the human integrin beta 7 protein complex determined using a rabbit anti-beta 7 peptide antibody raised to an N-terminal 22 amino acid residue sequence deduced from the human beta 7 subunit cDNA. The beta 7 subunit (Mr 116,000) expressed on PHA lymphoblasts associates with a single major alpha subunit (alpha H) that is distinct from the prominent T cell marker, integrin alpha 4. The alpha H subunit (Mr 180,000 nonreduced) displays a distinctive shift in size on reduction to an apparent Mr of 150,000. We show that these structural properties of the integrin beta 7 complex are shared with the cell surface antigen HML-1 found highly expressed on T cells which populate the intestinal epithelium and are proposed to be involved in mucosal immunity. Sequential immunoprecipitation and Western blotting demonstrate identity or close homology between the alpha H beta 7 and HML-1 proteins.

Amino Acid Sequence↗
PubMed1988

Effect of granulocyte-macrophage colony-stimulating factor and interleukin 3 on the v-src oncogene. Inhibition of tyrosine kinase activity in the absence of changes in gene expression.

Three cloned murine interleukin 3 (IL-3)-dependent cell lines have been converted to interleukin 2 (IL-2) or granulocyte-macrophage colony-stimulating factor (GM-CSF) growth-dependent states. FD.C/1 32Dcl-23 and GM cells grown and maintained as IL-3-dependent cell lines, and cells grown with GM-CSF have been infected with a murine recombinant retrovirus containing the v-src oncogene, and grown as lymphokine-independent cell lines. There is a significant increase in tyrosine kinase activity in cells which become lymphokine-independent. FD.C/1 and 32Dcl-23 cells maintained as IL-2-dependent cells lines and infected with the same virus did not grow as IL-2-independent cells. The lymphokine-independent cells FD.C/1src, 32Dsrc, and GMsrc all expressed high levels of tyrosine kinase activity, ranging from 5- to 20-fold more than levels measured in virus-infected cell lines maintained as IL-2-dependent cells. The exposure of FD.C/1src and 32Dsrc cells to IL-3, and GMsrc cells to IL-3 or GM-CSF, resulted in significant decreases in tyrosine kinase activity. These changes were rapidly reversed by removal of IL-3 or GM-CSF from these cells. However, the synthesis of v-src-specific RNA was not affected by the presence of IL-3 or GM-CSF in these cell lines. The biochemical pathways activated by IL-3 or GM-CSF inhibit the activity of the tyrosine kinase encoded by the v-src oncogene without altering gene transcription.

Animals↗
PubMed1987

Expression of genes in cloned murine cell lines that can be maintained in both interleukin 2- and interleukin 3-dependent growth states.

Two cloned murine cell lines, FD.C/1 and 32Dcl-23 exhibit switching of lymphokine-dependent growth states. The bone marrow-derived FD.C/1 and 32Dcl-23 cell lines are normally grown in culture medium supplemented with interleukin 3 (IL3). The replacement of IL3 with interleukin 2 (IL2) in the medium results in an increase in IL2 receptor expression in FD.C/1 and 32Dcl-23 cells and the switching of cells to an IL2-dependent growth state. We have compared patterns of protein and phosphoprotein synthesis, as well as the expression of the c-abl, c-ras, c-myb, and c-fos oncogenes in these cell lines maintained in IL3- and IL2-dependent growth states. The synthesis of a series of proteins and phosphoproteins are identified with each of the lymphokine-dependent growth states. All of the oncogenes examined are expressed in both IL2- and IL3-dependent cells and are not altered by phenotypic changes in lymphokine growth dependence. The relationship of oncogene expression to intracellular pathways regulated by lymphokine-receptor interactions is considered.

Animals↗
PubMed1985

Covalent binding of [35S]cysteine to the labile binding site of the third component of complement: a physiological approach.

The alternative pathway of complement was activated physiologically by agarose beads to which [35S]cysteine had been bound by a disulfide link. The activated form of the third component of complement, C3b, which had bound to the radioactive cysteine was then released from the agarose bead with dithiothreitol. The [35S]cysteine was shown to be covalently bound to the alpha' chain of C3b, and to its known major breakdown product, the 66,000-Da polypeptide. This is highly suggestive that complement activation has led to formation of a peptide bond between the radioactive cysteine and the labile binding site on the alpha' chain of C3b. This radioactive marker will enable the amino acid sequence of the labile binding site to be determined, with the knowledge that the labeling of the amino acid(s) has occurred during physiological activation.

Complement Activation↗