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Biomedical subjects

H R Smith

Publications and source records attributed to H R Smith.

At least 91 records · Page 5Linked to original sources
PubMed1998

Serum antibodies to secreted proteins in patients infected with Escherichia coli O157 and other VTEC.

Certain strains of verotoxigenic Escherichia coli (VTEC), and in particular those belonging to serogroup O157, cause attaching and effacing (AE) lesions of the host gut mucosa during pathogenesis. The mechanisms involved with bacterial attachment and the destruction of microvilli are determined by a cluster of genes within the LEE region, which also encode five secreted proteins. Sera from patients with antibodies to the lipopolysaccharide (LPS) of E. coli O157 and other VTEC were tested for antibodies to these secreted proteins. Twenty-one of 34 (62%) sera with antibodies to the lipopolysaccharide (LPS) of E. coli O157 also contained antibodies to one or more of the secreted proteins. Five of 12 sera containing antibodies to the LPS of a range of other VTEC serogroups also contained antibodies to 1 or more of the 5 secreted proteins, as did 16 of 70 (23%) sera from patients with haemolytic uraemic syndrome (HUS), haemorrhagic colitis (HC) or diarrhoea, but without bacteriological evidence of infection with VTEC and which did not contain antibodies to VTEC serogroups O5, O115, O145, O153 or O157. The detection of serum antibodies to secreted proteins may provide additional information for interpreting the results of established lipopolysaccharide-based VTEC serology.

Antibodies, Bacterial↗
PubMed1998

Long-acting blockade of biogenic amine transporters in rat brain by administration of the potent novel tropane 2beta-propanoyl-3beta-(2-Naphthyl)-tropane.

2beta-Propanoyl-3beta-(2-naphthyl)-tropane (WF-23) is a potent cocaine analog with activity at dopamine and serotonin transporters. The purpose of these experiments was to characterize the time course of effects of acute administration of WF-23 on spontaneous locomotion and biogenic amine transporters. Rats received injections i.p. with WF-23 (1 mg/kg), cocaine (30 mg/kg) or vehicle and locomotor activity was measured at various times postinjection. Animals were killed immediately after behavioral activity. Locomotor activity was significantly increased by WF-23 administration, reaching maximum at 4 hr and persisting for 24 hr. Cocaine-elicited elevations in locomotor activity occurred only at the earliest times. WF-23 decreased DA transporter binding in striatal membranes ([125I]RTI-55 binding), with >50% loss in binding for up to 49 hr postinjection. WF-23 increased the Kd of the high affinity site, with no effect on Bmax. Cocaine depressed binding (20%) only at the earliest times. WF-23 decreased levels of [3H]WIN 35,428 binding sites up to 95% of control in both dorsal and ventral striatum with a similar time-course when assessed autoradiographically. WF-23 also reduced [3H]citalopram binding to serotonin transporter sites throughout the brain. The slow onset and very long duration of action of WF-23, taken together with its actions at dopamine and serotonin transporters, suggest a potential role for treatment of disorders characterized by their involvement of these neural systems.

Animals↗
PubMed1998

Improved serological detection of infection with Vero cytotoxin producing Escherichia coli.

Vero cytotoxin producing Escherichia coli (VTEC)--including all those of serogroup O157--and enteropathogenic E. coli produce attaching and effacing lesions in gut epithelium. Immunoblotting was used to detect antibodies to secreted proteins associated with the formation of these lesions. These tests should provide additional evidence of VTEC infection in conjunction with current assays for antibioties to E. coli O157 lipopolysaccharide.

Bacterial Toxins↗
PubMed1997

Magnesium ions are required for HEp-2 cell adhesion by enteroaggregative strains of Escherichia coli O126:H27 and O44:H18.

Enteroaggregative strains of Escherichia coli, belonging to serotypes O44:H18 and O126:H27, were used to show that magnesium ions were essential for the adhesion of these enteroaggregative strains to HEp-2 cells. The removal of Mg2+ ions from culture media was correlated with the inability of strains to produce an outer membrane-associated protein of 18 kDa and a pellicle. It was concluded that magnesium ions were directly involved with the expression of an 18 kDa outer membrane-associated protein by strains of E. coli O126:H27 and O44:H18, and that the outer membrane-associated protein was involved in both HEp-2 adhesion and pellicle formation.

Antibody Specificity↗
PubMed1997

Identification of entero-aggregative Escherichia coli based on surface properties.

Twenty-nine strains of Escherichia coli that adhere to HEp-2 cells with a 'stacked brick' pattern (EAggEC), and four nonadherent control strains, were examined for the ability to hybridize with gene probes for aggregative (AA) and diffuse (DA) HEp-2 cell adhesion phenotypes. These strains were also tested for the ability to express an 18 kDa membrane-associated outer-membrane protein (MAP), to agglutinate erythrocytes, and to produce a pellicle during broth culture. Thirteen of the 29 HEp-2 adherent strains of E. coli hybridized with the gene probes for both AA and DA, and expressed an 18 kDa outer membrane protein (OMP) which was antigenically related to the MAP expressed by strains of E. coli O126:H27. The strains that did not carry the additional DA genes did not express an 18 kDa OMP. Although strains of EAggEC share the ability to adhere to HEp-2 cells with a stacked brick pattern, these strains exhibit a diverse range of physical and biochemical properties. From the results of this study, it was concluded that currently, the possession of EAggEC genes or the ability to adhere to HEp-2 cells in a stacked brick formation, remain the only reliable means of identifying EAggEC.

Bacterial Adhesion↗
PubMed1997

250 years of military dermatology: the British Army experience.

The British Army has encountered significant morbidity due to skin disease from the eighteenth century to the present time. The young age and pre-deployment screening of soldiers coupled with adverse environmental conditions produce a predominance of infective and eczematous conditions. The dermatologist still has a significant contribution to make in keeping the individual soldier healthy.

Dermatology↗
PubMed1997

Skin disease in British troops in the Bosnian winter.

During the winter of 1995-1996, there took place a major deployment of North Atlantic Treaty Organization peacekeeping forces to Bosnia. Epidemiological surveillance of British troops through the ARRC-97 program has provided detailed information about their dermatological health. Skin disease was responsible for 12.7% of primary care consultations. Dry skin prove a common problem for troops. We recommend that emollients be placed on general issue during winter deployments to the Balkans. Dermatology should be included in pre-Bosnia training for all medical personnel.

Adult↗
PubMed1997

Aeromedical evacuation in Bosnia.

The objective of this study was to assess the value of aeromedical evacuation when compared to road ambulance transportation in predominantly trauma patients in a rural area. Uniquely, trauma was the most common presenting condition (75%), distances to secondary care facilities were long and road routes were poor with a risk of being mined. Data were collected of all British aeromedical flights in Multi-National Division Southwest, Bosnia-Herzegovina, over a six-month period, and benefit to the patient was assessed by a panel of experts when compared to calculated road ambulance evacuation. Sixty-nine patients were evacuated by air on 57 flights and transported to a secondary care facility for further management. The panel of experts found that only 15 of the 69 patients (22%) had benefited from aeromedical evacuation. This study again shows the low benefit to the patient from indiscriminate use of aeromedical evacuation, despite the air ambulance being operated in apparently ideal conditions of a high percentage of trauma, a rural setting and poor road communications. Crew safety and the high costs further highlight the need to devise a system that can screen out unnecessary flights and identify those patients who would benefit most.

Adult↗
PubMed1996

The Ly-49D receptor activates murine natural killer cells.

Proteins encoded by members of the Ly-49 gene family are predominantly expressed on murine natural killer (NK) cells. Several members of this gene family have been demonstrated to inhibit NK cell lysis upon recognizing their class I ligands on target cells. In this report, we present data supporting that not all Ly-49 proteins inhibit NK cell function. Our laboratory has generated and characterized a monoclonal antibody (mAb) (12A8) that can be used to recognize the Ly-49D subset of murine NK cells. Transfection of Cos-7 cells with known members of the Ly-49 gene family revealed that 12A8 recognizes Ly-49D, but also cross-reacts with the Ly-49A protein on B6 NK cells. In addition, 12A8 demonstrates reactivity by both immuno-precipitation and two-color flow cytometry analysis with an NK cell subset that is distinct from those expressing Ly-49A, C, or G2. An Ly-49D+ subset of NK cells that did not express Ly-49A, C, and G2 was isolated and examined for their functional capabilities. Tumor targets and concanovalin A (ConA) lymphoblasts from a variety of H2 haplotypes were examined for their susceptibility to lysis by Ly-49D+ NK cells. None of the major histocompatibility complex class I-bearing targets inhibited lysis of Ly-49D+ NK cells. More importantly, we demonstrate that the addition of mAb 12A8 to Ly-49D+ NK cells can augment lysis of Fc gamma R+ target cells in a reverse antibody-dependent cellular cytotoxicity-type assay and induces apoptosis in Ly-49D+ NK cells. Furthermore, the cytoplasmic domain of Ly-49D does not contain the V/Ix-YxxL immunoreceptor tyrosine-based inhibitory motif found in Ly-49A, C, or G2 that has been characterized in the human p58 killer inhibitory receptors. Therefore, Ly-49D is the first member of the Ly-49 family characterized as transmitting positive signals to NK cells, rather than inhibiting NK cell function.

Amino Acid Sequence↗
PubMed1996

PHLS begins a national case control study of Escherichia coli O157 infection in England.

Infection with Vero cytotoxin producing Escherichia coli O157 (VTEC O157) is a growing public health problem and the commonest cause of acute renal failure in children in the United Kingdom. Foodborne outbreaks of VTEC O157 infection have been reported in the United Kingdom, other European countries, and North America. Most cases of infection are sporadic, however, and the contribution of food vehicles, animal contact, and person to person spread in the acquisition of infection needs to be clarified. The PHLS is starting a case control study in England to identify and estimate the relative importance of risk factors for the acquisition of VTEC O157 infection. The study will run for 12 months. This article describes its objectives and asks microbiologists, public health physicians, clinicians, and others who may be asked for details about cases or to find suitable controls for their help in achieving a successful outcome.

Case-Control Studies↗