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Biomedical subjects

G Hill

Publications and source records attributed to G Hill.

At least 55 records · Page 3Linked to original sources
PubMed1998

Host reactive donor T cells are associated with lung injury after experimental allogeneic bone marrow transplantation.

Noninfectious lung injury is common after allogeneic bone marrow transplantation (BMT), but its association with acute graft-versus-host disease (GVHD) is unclear. Using a murine BMT system where donor and host differ by multiple minor histocompatibility (H) antigens, we investigated the nature of lung injury and its relationship both to systemic GVHD and host-reactive donor T cells. Lethally irradiated CBA hosts received syngeneic BMT or allogeneic (B10.BR) T-cell-depleted (TCD) bone marrow (BM) with and without the addition of T cells. Six weeks after BMT, significant pulmonary histopathology was observed in animals receiving allogeneic BMT compared with syngeneic controls. Lung damage was greater in mice that received allogeneic T cells and developed GVHD, but it was also detectable after TCD BMT when signs of clinical and histologic acute GVHD were absent. In each setting, lung injury was associated with significant alterations in pulmonary function. Mature, donor (Vbeta6(+) and Vbeta3(+)) T cells were significantly increased in the broncho-alveolar lavage (BAL) fluid of all allogeneic BMT recipients compared with syngeneic controls, and these cells proliferated and produced interferon-gamma (IFN-gamma) to host antigens in vitro. These in vitro responses correlated with increased IFN-gamma and tumor necrosis factor-alpha (TNF-alpha) in the BAL fluid. We conclude that alloreactive donor lymphocytes are associated with lung injury in this allogeneic BMT model. The expansion of these cells in the BAL fluid and their ability to respond to host antigens even when systemic tolerance has been established (ie, the absence of clinical GVHD) suggest that the lung may serve as a sanctuary site for these host reactive donor T cells. These findings may have important implications with regard to the evaluation and treatment of pulmonary dysfunction after allogeneic BMT even when clinical GVHD is absent.

Animals↗
PubMed1998

The Vitek analyser for routine bacterial identification and susceptibility testing: protocols, problems, and pitfalls.

Automated and semiautomated technology in microbiology has seen great advances in recent years. The choice of automated equipment for the identification and susceptibility testing of bacteria in a routine diagnostic laboratory depends on speed, accuracy, ease of use, and cost factors. The Vitek analyser (bioMerieux, UK) was installed in a busy diagnostic teaching hospital laboratory in London. This report describes one year's experience. Changes to work practice as a result of incorporating the equipment into the laboratory, and the advantages and disadvantages of automation in key areas are described in detail, together with possible solutions to problems. The Vitek analyser was found to be valuable for the speed and accuracy with which results were available for the common bacterial pathogens. Results of susceptibility testing were standardised according to NCCLS guidelines and used breakpoint MICs to ascertain susceptibility and resistance; they were an improvement on disc testing. This equipment is not a reference facility for difficult to identify organisms and many manual techniques, including some disc susceptibility testing, will have to be retained by the laboratory.

Bacterial Typing Techniques↗
PubMed1998

Nitric oxide is formed in a subpopulation of rat pineal cells and acts as an intercellular messenger.

In the rat pineal, formation of the second messenger cyclic GMP (cGMP) is under adrenergic control. Two important sequential steps mediate adrenergic signal transduction by cGMP, receptor-stimulated nitric oxide (NO) formation by the enzyme NO synthase I (NOS I), and NO-induced cGMP formation by the cytosolic enzyme guanylyl cyclase. With regard to the first step in cGMP transduction (i.e. NO formation) we found, by means of NOS I immunostaining and NADPH-diaphorase staining, that the presence of NOS I was restricted to a subpopulation of pineal cells, generally surrounded by NOS I-negative cells. Considering the fact that NO is able to permeate the cell membrane, the question arises whether the second step in cGMP signalling (i.e. NO-induced cGMP formation) is restricted to the NO-forming cell itself or takes place in neighboring cells as well. It was found that oxyhemoglobin, which scavenges NO but does not enter cells, strongly decreased adrenergic cGMP response. This suggests that a considerable part of adrenergically induced NO stimulates cGMP formation in neighboring cells. Our findings indicate that in the rat pineal the components of adrenergic cGMP transduction are largely distributed among two types of cells: NOS I-containing pineal cells where adrenoceptor stimulation induces NO formation, and neighboring cells in which NO stimulates cGMP formation.

Animals↗
PubMed1998

Commentary: Medicaid reform issues affecting the Indian health care system.

Substantial numbers of Indian people rely on Medicaid for their primary health insurance coverage. When state Medicaid programs enroll Indians in managed care programs, several unintended consequences may ensue. This paper identifies some of the perverse consequences of Medicaid reform for Indians and the Indian health care system and suggests strategies for overcoming them. It discusses the desire of Indian people to receive culturally appropriate services, the need to maintain or improve Indian health care system funding, and the duty of state governments to respect tribal sovereignty. Because of their relatively small numbers, Indians may be treated differently under Medicaid managed care systems without significantly endangering anticipated program savings. Failure of Medicaid programs to recognize the uniqueness of Indian people, however, may severely weaken the Indian health care system.

Eligibility Determination↗
PubMed1997

International Federation of Clinical Chemistry and International Union of Pure and Applied Chemistry 2. Properties and Units in the Clinical Laboratory Sciences. VI. Properties and Units in IOC Prohibited Drugs (IFCC-IUPAC Recommendations 1997).

The term designating a substance being an active ingredient of a drug may be a generic name, a nonproprietary name, a registered trade name, a fantasy name or other. This causes difficulties in the transmission of request and report on such substances to and from the clinical laboratories, and in the collating of this information from different sources. The document comprises a list of properties of drugs of abuse in biological fluids as defined by the International Olympic Committee Medical Code for use in electronic transmission systems. Standard systematic names are presented with a code value for each. The coding schemes thus prepared are accessible on Internet from C-NPU Home page address: http://inet.uni-c.dk/ qukb7642.

Pharmaceutical Preparations↗
PubMed1997

Plasma concentrations of tumour necrosis factor-alpha and interleukin-6 during burn wound surgery or dressing.

BACKGROUND: Clinical deterioration after burn wound manipulation may be related to the release of cytokines including tumour necrosis factor-alpha (TNF) and interleukin-6 (IL-6). METHODS: The two cytokines were assayed by immunoenzymetric assay in blood samples taken before and during manipulation of the burn wound. An antibiotic, teicoplanin, was administered to half the patients at the start of the procedure in a randomized fashion as part of a separate trial. FINDINGS: Sixty patients with a median burn size of 8% (range 1-56%) were studied during dressing change (n = 40) or burn excision (n = 20). There was little change in TNF levels between preoperative and recovery samples but IL-6 concentrations increased three-fold, particularly in those with large recent burns or bacteraemia, and were correlated with poor clinical outcome. The presence of teicoplanin did not significantly affect the levels of either cytokine. INTERPRETATION: The systemic cytokine response to burn wound dressing or debridement is predominantly that of IL-6 and it is not significantly reduced by preventing Gram-positive bacteraemia during the procedure.

Adult↗
PubMed1997

Screening for neuroblastoma is ineffective in reducing the incidence of unfavourable advanced stage disease in older children.

Neuroblastoma exhibits many characteristics which would suggest that preclinical detection may improve outcome. The Quebec Neuroblastoma Screening Project was initiated to determine whether mass screening could reduce mortality in a large cohort of infants. All 476,603 children born in the province of Quebec during a 5-year period of time (1 May 1989 to 30 April 1994) were eligible for determinations of urinary catecholamine metabolites at 3 weeks and 6 months of age. Children with positive screening were referred to one of four paediatric cancer centres in Quebec for uniform evaluation and treatment. Standardised incidence ratios (SIRs) were calculated for neuroblastoma in Quebec and two comparable population-based controls during the same period of time using similar ascertainment procedures. Compliance with screening in Quebec was 91% at 3 weeks (n = 425,816) and 74% at 6 months (n = 349,706). Up to 31 July 1995 with a follow-up of the birth cohort of 15-75 months, 118 cases of neuroblastoma were diagnosed, 43 detected preclinically by screening, 20 detected clinically prior to screening at 3 weeks of age and 55 detected clinically after 3 weeks of age having normal screens (n = 52) or never screened (n = 3). Based on data from concurrent control populations, 54.5 cases of neuroblastoma would have been expected in Quebec during the study period for an SIR of 2.17 (95% CI 1.79-2.57, P < 0.0001). For the two control groups, the overall SIR was 1.00 (NS). SIRs for Quebec by age at diagnosis in yearly intervals show a marked increased incidence under 1 year of age (SIR = 2.85, 95% CI 2.26-3.50), with no reduction in incidence in subsequent years. We conclude that screening for neuroblastoma markedly increases the incidence in infants without decreasing the incidence of unfavourable advanced stage disease in older children. It is unlikely that screening for neuroblastoma in infants will reduce the mortality of this disease.

Canada↗
PubMed1996

Transmission of the results of tests for International Olympic Committee-defined drugs of abuse.

The hardware and software facilities for electronic storage, transfer and handling of data is such that multipurpose databases can be made accessible without geographic restriction at low cost. The versatile and flexible underlying structures allow for ease of access and retrieval of data and gives presentation formats fully comparable to printed counterparts. Because of the apparent ease of use and because of the wider distribution of the information, misinterpretation is more likely to occur than in oral or written presentation for more restricted and more culturally homogeneous audiences. This necessitates some degree of harmonisation/standardisation of data on transfer, while allowing local expression forms at sender and receiver ends (Fig. 1). This document is part of an ongoing international effort to agree on some sort of "standardisation" of the transmission and presentation of "laboratory results". It centers on the domain of drugs of abuse as defined by the International Olympic Committee.

Clinical Laboratory Information Systems↗