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Biomedical subjects

A King

Publications and source records attributed to A King.

At least 73 records · Page 4Linked to original sources
PubMed2001

Recommendations for susceptibility tests on fastidious organisms and those requiring special handling.

Fastidious organisms present problems in antimicrobial susceptibility testing related to particular cultural requirements or slow growth. Methods for commonly isolated fastidious organisms, including haemolytic streptococci, Neisseria spp. and Haemophilus spp., are included in the description of the standardized disc diffusion method. However, some further information is given here for Haemophilus influenzae and Neisseria spp. Other less commonly isolated fastidious organisms are detailed and modifications of the disc diffusion method are given for Campylobacter spp. and rapidly growing anaerobes. For those organisms where disc diffusion methodology is not recommended, Brucella spp., Helicobacter pylori and Leigionella spp., MIC determinations are often needed, although disc diffusion test results may be useful as screens for resistance. Where disc diffusion can be used it is important to use the correct medium and to include appropriate controls. Methodology is also given for testing isolates of Stenotrophomonas maltophilia, which are affected by both medium and temperature.

Anti-Bacterial Agents↗
PubMed2001

A survey of state programs to finance rehabilitation and community services for individuals with brain injury.

This article will review and compare existing state-funded programs and their approaches to financing, administering, and delivering an array of services, including rehabilitation and home and community-based services and supports to individuals with traumatic brain injury (TBI) and their families. A state-by-state chart provides funding and operational characteristics of the programs. The state menu of services provided and how they are delivered are also described. The article addresses how these programs fit within their overall state service delivery system, trends and changes that programs may be undergoing, and the influences that shape these programs.

Brain Injuries↗
PubMed2001

HLA-G expression by tumors.

PROBLEM: It has been proposed that the expression of the non-classical MHC class I antigen, HLA-G, by trophoblast is one mechanism by which the placenta evades attack by maternal uterine NK cells. A similar mechanism is thought to be operative in the escape from immunosurveillance by tumor cells. However, data on the expression of HLA-G by tumor cells are highly conflicting. METHOD OF STUDY: In the present study, we have examined tissue sections from a wide variety of tumors by immunohistology and also several cell lines by flow cytometry and RT-PCR. Whilst very faint bands were detected in three cell lines (hepG2, Mead, CaSki) by RT-PCR, no tumors or cell lines were observed to express HLA-G protein. Furthermore, we found that tumor deposits are not usually infiltrated by NK cells. CONCLUSION: Our observations, therefore, do not support the proposal that tumor cells express HLA-G in order to evade host NK cell cytolysis.

HLA Antigens↗
PubMed2001

Localization of c-Myb and induction of apoptosis by antisense oligonucleotide c-Myb after angioplasty of porcine coronary arteries.

Previous studies have shown that inhibition of the proto-oncogene c-myb inhibits neointimal formation in various animal models. However, the temporal and spatial expression of c-Myb in the vessel wall after injury is not known, and the mechanism of action of antisense oligonucleotide (AS-ODN-c-myb) inhibition remains unclear. One potential effect of cell cycle dysregulation by inhibition of c-myb is an increase in the rates of apoptosis. In this study, c-Myb expression after percutaneous transluminal coronary angioplasty (PTCA) injury and induction of apoptosis after AS-ODN-c-myb treatment were determined. Immunohistochemistry and cellular phenotyping were used to localize c-Myb expression in porcine coronary arteries at various time intervals after PTCA. In vitro, the effects of AS-ODN-c-myb on the apoptosis of porcine vascular smooth muscle cells (PVSMCs) and endothelial cells were determined by using a cell-death ELISA and time-lapse video microscopy. In vivo, local delivery of AS-ODN-c-myb was performed after PTCA of pig coronary arteries, and apoptosis was quantified at 6 hours. c-Myb is induced in pig coronary arteries after angioplasty, with maximal expression in inflammatory cells at 18 hours and in vascular smooth muscle cells at 3 to 7 days. In vitro, AS-ODN-c-myb enhanced PVSMCs (6.8+/-0.8% [P=<0.001] versus 0.5% serum) but not endothelial cell apoptosis (1.4+/-0.5% [P=NS] versus 0.5% serum). In vivo, 6 hours after porcine coronary angioplasty and delivery of AS-ODN-c-myb, the proportion of apoptotic cells within the media was 4.2+/-0.8% (PTCA alone), 2.3+/-0.2% (PTCA+vehicle), and 9.0+/-1.1% (PTCA+AS-ODN-c-myb; P<0.05 versus PTCA alone and P<0.01 versus PTCA+saline). c-Myb is expressed after PTCA of pig coronary arteries, and AS-ODN-c-myb induces apoptosis of PVSMCs in vitro and medial cells in vivo.

Angioplasty, Balloon, Coronary↗
PubMed2001

Angiogenic growth factor messenger ribonucleic acids in uterine natural killer cells.

Angiogenesis is essential for endometrial growth and repair, and disruption of this process may lead to common disorders of women, including menorrhagia and endometriosis. In pregnancy, failure of the endometrial spiral arterioles to undergo remodeling leads to preeclampsia. Here we report that in addition to vascular endothelial growth factor A (VEGF-A), human endometrium expresses messenger ribonucleic acids (mRNAs) encoding VEGF-C, placenta growth factor (PlGF), the angiopoietins, angiopoietin 1 (Ang1) and Ang2, and the receptors VEGFR-3 (Flt-4), Tie 1, and Tie 2. Levels of VEGF-C, PlGF, and Tie 2 changed during the menstrual cycle. Intense hybridization for VEGF-C and PlGF mRNAs was found in uterine nature killer cells in secretory phase endometrium and for Ang2 mRNA in the same cells in the late secretory phase. Interleukin-2 (IL-2) and IL-15 up-regulated VEGF-C, but not PlGF or Ang2, mRNA levels in isolated NK cells. Conditioned medium from decidual NK cells did not induce human umbilical vein endothelial cell apoptosis. These results indicate that human endometrium expresses a wide range of angiogenic growth factors and that uterine nature killer cells may play an important role in the abnormal endometrial angiogenesis that underlies a range of disorders affecting women.

Angiogenesis Inducing Agents↗
PubMed2001

Lymph node hilus: gray scale and power Doppler sonography of cervical nodes.

OBJECTIVE: To investigate the difference in the nodal hilus evaluated by gray scale and power Doppler sonography. METHODS: One hundred ninety-two patients with proven cervical lymphadenopathy were included in the study (metastases, n = 118; tuberculosis, n = 56; and lymphoma, n = 18). Lymph nodes were evaluated by gray scale sonography for the echogenic hilus and power Doppler sonography for hilar vascularity. RESULTS: Hilar vascularity was found even though the lymph node did not show an echogenic hilus on gray scale sonography (metastases, 59%; tuberculosis, 66%; and lymphoma, 91%). CONCLUSIONS: Sonologists should be aware that gray scale and Doppler sonography show different aspects of the hilus, and the absence of the hilus on gray scale sonography does not necessarily imply an associated absence of hilar vascularity.

Adolescent↗
PubMed2001

A national register for surveillance of inherited disorders: beta thalassaemia in the United Kingdom.

OBJECTIVE: To demonstrate the value of a national register for surveillance of services for an inherited disorder. METHODS: Data from the United Kingdom Thalassaemia Register and the United Kingdom Register of Prenatal Diagnosis for Haemoglobin Disorders were combined in a database; these registers include all fetuses known to have been diagnosed with beta thalassaemia major, beta thalassaemia intermedia, or haemoglobin E/beta thalassaemia in the United Kingdom. Data were extracted to show outcomes (selective abortion or live birth) of all fetuses and the status of those born with a disorder (alive, dead, successful bone marrow transplant, or lost to follow-up) by parents' region of residence and ethnicity. FINDINGS: At the end of 1999 the register included 1074 patients, 807 of whom were alive and residing in the United Kingdom. A successful bone marrow transplant has been performed for 117 out of 581 (20%) patients born since 1975. Residents of Pakistani origin are now the main group at risk in the United Kingdom, replacing residents of Cypriot origin. This has led to a marked shift in the need for services from the south-east of England to the Midlands and the north of England. Despite the acceptability of prenatal diagnosis, the proportion of affected births remains 50% higher than would be expected, reflecting a widespread failure to deliver timely screening and counselling to carriers. Even though effective treatment is available the annual number of deaths is rising, indicating that better tolerated treatments are needed. CONCLUSION: A national diagnosis register is a powerful instrument for monitoring the treatment and prevention of inherited disorders and for highlighting correctable shortcomings. In view of the increasing possibilities for genetic screening there is a strong case for central funding for such databases within modern health services.

Adolescent↗
PubMed2001

Long-term colonization levels of Helicobacter hepaticus in the cecum of hepatitis-prone A/JCr mice are significantly lower than those in hepatitis-resistant C57BL/6 mice.

Helicobacter hepaticus infection causes hepatitis in A/JCr mice but mild or no disease in C57BL/6 mice. Colonization of H. hepaticus in the cecum of experimentally infected A/JCr and C57BL/6 mice was quantified by use of real-time polymerase chain reaction (PCR) analysis with primers for the H. hepaticus cdtB gene and mouse 18srRNA. Eight-week-old mice were experimentally (n = 48) or sham (n = 24) infected with H. hepaticus, then were necropsied 6 months after infection. Liver specimens from experimentally infected mice had negative results of PCR analysis for H. hepaticus; thus, real-time quantification was not attempted. Quantitative PCR analysis of H. hepaticus in cecal specimens indicated that C57BL/6 mice were colonized to a greater extent than were A/JCr mice (P < 0.006). Appreciable typhlitis was not observed, but was consistent with that of previous reports; A/JCr mice developed more severe parenchymal necrosis, portal inflammation, and phlebitis in the liver (P < 0.0001), with mild disease observed in infected C57BL/6 mice. Thus, hepatitis in A/JCr mice caused by H. hepaticus infection is associated with significantly lower colonization levels of H. hepaticus in the cecum, compared with those of hepatitis-resistant C57BL/6 mice. Host responses of A/JCr mice that limit cecal colonization with H. hepaticus may have important roles in the pathogenesis of hepatic lesions.

Animals↗
PubMed2000

Induction of antigen-specific CD8+ T cells, T helper cells, and protective levels of antibody in humans by particle-mediated administration of a hepatitis B virus DNA vaccine.

A DNA vaccine against the hepatitis B virus (HBV) was evaluated for safety and induction of immune responses in 12 healthy, hepatitis-naïve human volunteers using the needle-free PowderJect system to deliver gold particles coated with DNA directly into cells of the skin. Three groups of four volunteers received three administrations of DNA encoding the surface antigen of HBV at one of the three dose levels (1, 2, or 4 microg). The vaccine was safe and well tolerated, causing only transient and mild to moderate responses at the site of administration. HBV-specific antibody and both CD4+ and CD8+ T cell responses were measured before and after each immunization. All the volunteers developed protective antibody responses of at least 10 mIU/ml. In volunteers who were positive for the HLA class I A2 allele, the vaccine also induced antigen-specific CD8+ T cells that bound HLA-A2/HBsAg(335-343) tetramers, secreted IFN-gamma, and lysed target cells presenting a hepatitis B surface antigen (HBsAg) CTL epitope. Enumeration of HBsAg-specific T cells producing cytokine indicated preferential induction of a Type 1 T helper cell response. These results provide the first demonstration of a DNA vaccine inducing protective antibody titers and both humoral and cell-mediated immune responses in humans.

Adult↗
PubMed2000

Cytokine-induced functional suppression of microencapsulated rat pancreatic islets in vitro.

BACKGROUND: It is likely that inflammatory cytokines are released near microencapsulated islets in vivo. METHODS: Rates of insulin release or glucose oxidation were measured after culture of microencapsulated rat islets with interleukin (IL)-1beta and tumor necrosis factor-(TNF-alpha). Their ability to recover from IL-1beta-induced suppression was also investigated. RESULTS: Microencapsulated islets were suppressed after exposure to IL-1beta, which was potentiated by TNF-alpha. After exposure to lower IL-1beta concentrations, microencapsulated islets had similar oxidation rates as corresponding controls. At higher concentrations, microencapsulated islets were more suppressed than nonencapsulated islets. Microencapsulated and control islets were able to recover from suppression after exposure to 2.5 U/ml of IL-1beta. CONCLUSIONS: Microencapsulation using the present alginate/poly-L-lysine/alginate capsules does not protect islets against the detrimental effects of IL-1beta and TNF-alpha. Indeed, microencapsulated islets seem to be more susceptible to suppression at higher concentrations of IL-1beta. However, after exposure to a lower concentration of IL-1beta, microencapsulated islets can recover.

Animals↗
PubMed2000

HIV-specific CD8(+) T cells produce antiviral cytokines but are impaired in cytolytic function.

The use of peptide-human histocompatibility leukocyte antigen (HLA) class I tetrameric complexes to identify antigen-specific CD8(+) T cells has provided a major development in our understanding of their role in controlling viral infections. However, questions remain about the exact function of these cells, particularly in HIV infection. Virus-specific cytotoxic T lymphocytes exert much of their activity by secreting soluble factors such as cytokines and chemokines. We describe here a method that combines the use of tetramers and intracellular staining to examine the functional heterogeneity of antigen-specific CD8(+) T cells ex vivo. After stimulation by specific peptide antigen, secretion of interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, macrophage inflammatory protein (MIP)-1beta, and perforin is analyzed by FACS((R)) within the tetramer-positive population in peripheral blood. Using this method, we have assessed the functional phenotype of HIV-specific CD8(+) T cells compared with cytomegalovirus (CMV)-specific CD8(+) T cells in HIV chronic infection. We show that the majority of circulating CD8(+) T cells specific for CMV and HIV antigens are functionally active with regards to the secretion of antiviral cytokines in response to antigen, although a subset of tetramer-staining cells was identified that secretes IFN-gamma and MIP-1beta but not TNF-alpha. However, a striking finding is that HIV-specific CD8(+) T cells express significantly lower levels of perforin than CMV-specific CD8(+) T cells. This lack of perforin is linked with persistent CD27 expression on HIV-specific cells, suggesting impaired maturation, and specific lysis ex vivo is lower for HIV-specific compared with CMV-specific cells from the same donor. Thus, HIV-specific CD8(+) T cells are impaired in cytolytic activity.

CD8-Positive T-Lymphocytes↗
PubMed2000

Nucleic acid mutation analysis using catalytic DNA.

The sequence specificity of the '10-23' RNA-cleaving DNA enzyme (deoxyribozyme) was utilised to discriminate between subtle differences in nucleic acid sequence in a relatively conserved segment of the L1 gene from a number of different human papilloma virus (HPV) genotypes. DNA enzymes specific for the different HPV types were found to cleave their respective target oligoribonucleotide substrates with high efficiency compared with their unmatched counterparts, which were usually not cleaved or cleaved with very low efficiency. This specificity was achieved despite the existence of only very small differences in the sequence of one binding arm. As an example of how this methodology may be applied to mutation analysis of tissue samples, type-specific deoxyribozyme cleavable substrates were generated by genomic PCR using a chimeric primer containing three bases of RNA. The RNA component enabled each amplicon to be cleavable in the presence of its matching deoxyribozyme. In this format, the specificity of deoxyribozyme cleavage is defined by Watson-Crick interactions between one substrate-binding domain (arm I) and the polymorphic sequence which is amplified during PCR. Deoxy-ribozyme-mediated cleavage of amplicons generated by this method was used to examine the HPV status of genomic DNA derived from Caski cells, which are known to be positive for HPV16. This method is applicable to many types of nucleic acid sequence variation, including single nucleotide polymorphisms.

Capsid Proteins↗
PubMed2000

Biotransformation of monoterpene alcohols by Saccharomyces cerevisiae, Torulaspora delbrueckii and Kluyveromyces lactis.

Monoterpenoids are important flavour compounds produced by many plant species, including grapes (Vitis vinifera) and hops (Humulus lupulus). Biotransformation reactions involving monoterpenoids have been characterized in filamentous fungi, but few examples have been observed in yeasts. As monoterpenoids are in contact with yeasts during beer and wine production, biotransformation reactions may occur during the fermentation of these beverages. This paper describes the biotransformation of monoterpene alcohols, of significance in the alcoholic beverage industries, by three yeast species. All three species analysed had the ability to convert monoterpenoids. Saccharomyces cerevisiae and Kluyveromyces lactis reduced geraniol into citronellol, whilst all three yeasts produced linalool from both geraniol and nerol. Monocyclic alpha-terpineol was formed from both linalool and nerol, by all three yeasts. alpha-Terpineol was then converted into the diol cis-terpin hydrate. K. lactis and Torulaspora delbrueckii also had the ability to form geraniol from nerol. Finally, the stereospecificity of terpenoid formation was analysed. Both (+) and (-) enantiomers of linalool and alpha-terpineol were formed in roughly equal quantities, from either geraniol or nerol.

Acyclic Monoterpenes↗
PubMed2000

HLA-E is expressed on trophoblast and interacts with CD94/NKG2 receptors on decidual NK cells.

Non-classical MHC class I molecule HLA-E is the ligand for CD94/NKG2 NK cell receptors. Surface expression of HLA-E requires binding of specific HLA class I leader sequences. The uterine mucosa in early pregnancy (decidua) is infiltrated by large numbers of NK cells, which are closely associated with placental trophoblast cells. In this study we demonstrate that trophoblast cells express HLA-E on their cell surface in addition to the previously reported expression of HLA-G and HLA-C. Furthermore, we show that the vast majority of decidual NK cells bind to HLA-E tetrameric complexes and this binding is inhibited by mAb to CD94. Thus, recognition of fetal HLA-E by decidual NK cells may play a key role in regulation of placentation. The functional consequences of decidual NK cell interaction were investigated in cytotoxicity assays using polyclonal decidual NK cells. The overall effect of CD94/NKG2 interaction with HLA-E is inhibition of cytotoxicity by decidual NK cells. However, since decidual NK cells are unable to kill trophoblast even in the presence of mAb to MHC class I molecules and NK cell receptors, HLA-E interaction with CD94/NKG2 receptors may regulate other functions besides cytolysis during implantation.

Antigens, CD↗
PubMed2000

Towards the proteome of Mycobacterium tuberculosis.

Human tuberculosis is caused by the intracellular pathogen Mycobacterium tuberculosis. Sequencing of the genome of M. tuberculosis strain H37Rv has predicted 3924 open reading frames, and enabled identification of proteins from this bacterium by peptide mass fingerprinting. Extracellular proteins from the culture medium and proteins in cellular extracts were examined by two-dimensional gel electrophoresis using immobilized pH gradient technology. By mass spectrometry and immunodetection, 49 culture filtrate proteins and 118 lysate proteins were identified, 83 of which were novel. To date, 288 proteins have been identified in M. tuberculosis proteome studies, and a list is presented which includes all identified proteins (available at http://www.ssi.dk/publichealth/tbimmun). The information obtained from the M. tuberculosis proteome so far is discussed in relation to the information obtained from the complete genome sequence.

Bacterial Proteins↗
PubMed2000

A case of Miller-Dieker syndrome in a family with neurofibromatosis type I.

The Miller-Dieker syndrome (type I lissencephaly) is a neuronal migration disorder which is associated with microdeletions in the short arm of chromosome 17. Neurofibromatosis type I (NF1) is an autosomal dominant condition associated with mutations in the long arm of chromosome 17, and characterised by neurofibromas, café-au-lait spots and axillary freckling. The neonatal period for a female infant born at 39 weeks gestation by emergency Caesarean section was complicated by frequent epileptic seizures as well as hypotonia. A computed tomography scan revealed evidence of lissencephaly, and chromosomal analysis showed a microdeletion on the short arm of chromosome 17 (17p13.3), confirming the diagnosis as Miller-Dieker syndrome. The child died at the age of 4 years and examination of the brain confirmed lissencephaly with a thickened cortex, deficient white matter, and grey matter heteropias. The mother had café-au-lait spots, and axillary freckling. In addition, the mother's and maternal grandmother's genetic analysis showed identical mutations in the neurofibromatosis I gene on the long arm of chromosome 17, confirming the diagnosis of NF1. The child did not possess the mutation. This case illustrates a rare neuronal migration disorder appearing in a child from a family with a history of NF1.

Abnormalities, Multiple↗