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Biomedical subjects

P Bell

Publications and source records attributed to P Bell.

At least 55 records · Page 3Linked to original sources
PubMed1995

Efficacy of Coxiella burnetii and its chloroform-methanol residue (CMR) fraction against Rift Valley fever virus infection in mice.

Strains of Coxiella burnetii phase I and II whole cells (WC-I and WC-II) or whole cell fractions were assessed for their potential to induce long-lasting protection in endotoxin-non-responder C3H/HeJ or CD-1 mice against Rift Valley fever (RVF) virus challenge. Among the whole cell fractions, only the chloroform-methanol residue (CMR), administered as a single dose (100 micrograms per mouse) 24 h before viral challenge, effectively protected 100% of the mice from RVF virus; the CMR of the Ohio strain of C. burnetii was not protective. Most of the RVF virus-infected mice treated with other C. burnetii cell fractions died, although their times to death varied. Lipopolysaccharide (LPS) associated with CMR preparations used in these studies, did not protect against RVF virus challenge. A single dose of 100 micrograms of CMR given 24 h before viral challenge completely eradicated 4-5 logs of RVF virus in the serum, liver, spleen, and central nervous system. Compared to several other immunomodulators, CMR was an equally effective antiviral agent. Efficacy of CMR of both Henzerling and Ohio strains disappeared or was marginal when treatment was initiated 2-3 days before RVF viral challenge, even when a second or a third dose of CMR was administered after challenge. A single dose of liposome-encapsulated CMR to RVF virus-infected mice extended the range of therapeutic efficacy of this biologically active component of C. burnetii to 4 days before infection.

Adjuvants, Immunologic↗
PubMed1995

Characterization of the non-specific humoral and cellular antiviral immunity stimulated by the chloroform-methanol residue (CMR) fraction of Coxiella burnetii.

Modulation of the immune response by the chloroform-methanol residue (CMR) of phase I Coxiella burnetii whole cell was studied in Rift Valley fever virus-infected, or in naive endotoxin-non-responder C3H/HeJ mice. A single dose of CMR completely protected the mice from viral infection. Treating virus-infected mice with antibodies directed against interferons alpha/beta (IFN-alpha beta) and gamma (IFN-gamma) eliminated the CMR-induced protection. CMR stimulated the production of high levels of IFN-alpha/beta and 2'-5'-oligoadenylate synthetase activities in sera of the CMR-treated mice. IFN-gamma was present in supernatants of cultured spleen cells of CMR-treated, virus-infected mice, but not in their serum. Priming mice with CMR optimized the release of INF-gamma, interleukin-1 alpha (IL-1 alpha) and IL-6 from splenocytes in vitro. When stimulated in vitro, IL-2 and granulocyte-macrophage stimulating factor (GM-CSF) did not require in vivo priming for release from cultured spleen cells. Fluorescence-assisted cytometry of CMR-treated mouse spleen cells showed there was a CMR-dependent increase in the percentage of T-cells and Ia-positive T-cells. There also was a biphasic increase in the ratio between Th (L3T4) and Ts (Lyt2) cells. Biological activities stimulated by CMR indicate that CMR is a potent immunostimulant, which may modulate specific and non-specific antiviral responses.

2',5'-Oligoadenylate Synthetase↗
PubMed1995

Perception of the impact of assistive devices on daily life of three individuals with quadriplegia.

This qualitative study investigated the perceptions of three men with spinal cord injuries regarding the impact of assistive devices on their daily lives. Data were collected through open-ended face-to-face interviews and observations in the participants' homes. Thematic analysis yielded three recurrent themes; "getting out,'' "what do I do with all this time,'' and "I found an easier way.'' Concerns relating to personal freedom, choices, independence, and feelings regarding usefulness and control over daily lives were evident as main issues underlying the three themes. Assistive devices perceived as "advantageous'' were simple, appropriate for use in the home, and easy to use in the home. Devices perceived as "complex'' were abandoned or modified.

Activities of Daily Living↗
PubMed1995

Psychological consequences of the Kegworth air disaster.

BACKGROUND: The study sought to quantify psychiatric morbidity among survivors of a major air crash and to identify aetiological factors linked with post-traumatic stress disorder (PTSD). METHOD: Sixty-eight of the 79 survivors (86%) were assessed at a clinical interview within one year of the disaster. The majority also completed the General Health Questionnaire, the Impact of Events Scale (IES) and the Zung Anxiety and Depression Scales. RESULTS: Fifty-four of the study group (79%) met DSM-III-R criteria for a psychiatric disorder within one year of the disaster, of whom 27 (50%) had PTSD. Those who saw injured or dead people at the scene, or had sustained less severe injuries as measured by their Injury Severity Scores, or were under 35 years old, were significantly more likely to develop PTSD. CONCLUSIONS: High rates of psychiatric morbidity are found in survivors of transportation disasters. Further studies are needed to identify those at most risk and to evaluate the benefits of psychological intervention.

Adult↗
PubMed1994

The relationship of fasting insulin levels to vascular risk factors in a general practice in Northern Ireland.

OBJECTIVE: To investigate the relationship between insulin and vascular risk factors in a healthy male population at high risk of ischaemic heart disease. DESIGN: Computer-generated random number selection of subjects. SETTING: A suburban general practice population (total practice population 4500) in Northern Ireland. SUBJECTS: Four hundred male subjects, aged 35-65 years, were randomly selected with 273 responding. INTERVENTION: At interview, each subject completed a questionnaire, had blood pressure measured and a 12-lead ECG recorded. The next morning, fasting blood samples were taken and a timed overnight urine collection for the albumin excretion rate was returned. RESULTS: To exclude the confounding effects of other variables on insulin concentrations, a healthy nonobese, nondiabetic, normotensive group with no history of ischaemic heart disease, no family history of diabetes and not taking drugs was identified (n = 120). Within this group there was a significant correlation between insulin and triglyceride (r = 0.30; P < 0.05), high-density lipoprotein (HDL) cholesterol (r = 0.24; P < 0.05) and glucose (r = 0.30; P < 0.05). A group with higher insulin levels (n = 22) were compared to a group with lower insulin levels (n = 22). Serum triglyceride was higher (1.29 +/- 0.1 vs. 1.00 +/- 0.08 mmol L-1; P < 0.05), HDL cholesterol was lower (1.26 +/- 0.06 vs. 1.50 +/- 0.09 mmol L-1; P < 0.05) and plasma glucose higher (5.2 +/- 0.1 vs. 4.9 +/- 0.1 mmol L-1; P < 0.05) in the group with higher insulin levels. CONCLUSIONS: There is a relationship between insulin and triglyceride, HDL cholesterol and glucose but not blood pressure, cholesterol or low-density-lipoprotein (LDL) cholesterol in a healthy population at high risk of ischaemic heart disease.

Adult↗
PubMed1994

Recruitment for breast screening in a rural practice. Trial of a physician's letter of invitation.

OBJECTIVE: To evaluate a systematic effort to recruit women for breast screening. DESIGN AND SETTING: Individually addressed letters, signed by the woman's physician (followed by reminder letters and telephone calls as necessary) were sent to women in a rural family practice, prompting them to make an appointment for breast screening at the Ontario Breast Screening Program-the Kingston Centre. PARTICIPANTS: Women were eligible to receive a letter if they were aged 50 to 69, had not had a mammogram for at least 12 months, and did not have a previous diagnosis of breast cancer or current acute symptoms of breast disease. MAIN OUTCOME MEASURES: Response rates were measured to the initial letter, the reminder letter, and the telephone call. Women who came to the breast screening centre as a result of this recruitment effort were surveyed on their reaction to the letter. RESULTS: The response rate, as measured 9 months after the initial letters were sent, was 57.5%; 38% of respondents to the initial letter and 49% of respondents to the reminder letter said they would not have come to the centre without the letter. Both the breast screening program managers and the family physicians involved considered the project a success. CONCLUSION: Integrating with an organized breast screening program is one way for busy family physicians systematically to involve their patients in an early detection program without unduly burdening physicians or disrupting normal patient care.

Aged↗
PubMed1994

Private practice.

Explore the source record for details and available documents.

Holistic Health↗
PubMed1992

A mutant of TTX-resistant cardiac sodium channels with TTX-sensitive properties.

The cardiac sodium channel alpha subunit (RHI) is less sensitive to tetrodotoxin (TTX) and saxitoxin (STX) and more sensitive to cadmium than brain and skeletal muscle (microliter) isoforms. An RHI mutant, with Tyr substituted for Cys at position 374 (as in microliter) confers three properties of TTX-sensitive channels: (i) greater sensitivity to TTX (730-fold); (ii) lower sensitivity to cadmium (28-fold); and (iii) altered additional block by toxin upon repetitive stimulation. Thus, the primary determinant of high-affinity TTX-STX binding is a critical aromatic residue at position 374, and the interaction may take place possibly through an ionized hydrogen bond. This finding requires revision of the sodium channel pore structure that has been previously suggested by homology with the potassium channel.

Amino Acid Sequence↗
PubMed1992

The McCollough effect as a measure of central cholinergic activity in man.

The McCollough Effect (ME) is an orientation contingent colour after-effect which has been proposed as an indicator of central neurotransmitter activity. Shute (1979) suggested that the ME could reflect a hippocampal "forgetting" mechanism which should be inhibited by GABAergic neurones and stimulated by cholinergic neurones. The purpose of the present study was to demonstrate that the ME is in fact sensitive to cholinergic and anticholinergic drugs and to compare its sensitivity to more conventional tests of psychomotor and cognitive function. Ten healthy subjects received single doses of physostigmine (0.75 mg SC), hyoscine (1.2 mg), temazepam (20 mg), flecainide (200 mg) or placebo in a double-blind double-dummy presentation. Subjects were tested on a battery of psychomotor and cognitive function tests at baseline and 1 h, and adapted to the ME at 1.5 h. Visual analogue rating scales and conventional tests of psychomotor function and saccadic eye movements indicated that both subjective and objective measures of arousal were impaired by temazepam. The subjective, but not the objective, measures of arousal were also impaired by both hyoscine and physostigmine, but not by flecainide. Initial strength and duration of the ME were decreased by physostigmine and increased by hyoscine and temazepam, relative to placebo (P less than 0.01). Thus, the ME is capable of detecting cholinergic, anticholinergic and GABA mimetic drug effects in man, in therapeutic doses.

Adaptation, Ocular↗
PubMed1992

In vitro assembly of prenucleolar bodies in Xenopus egg extract.

Nuclei assembled in Xenopus egg extract from purified DNA or chromatin resemble their natural counterparts in a number of structural and functional features. However, the most obvious structural element of normal interphase nuclei, the nucleolus, is absent from the in vitro reconstituted nuclei. By EM, cytological silver staining, and immunofluorescence microscopy employing antibodies directed against various nucleolar components we show that nuclei assembled in vitro contain numerous distinct aggregates that resemble prenucleolar bodies (PNBs) by several criteria. Formation of these PNB-like structures requires pore complex-mediated nuclear transport of proteins but is independent of the genetic content of the in vitro nuclei as well as transcriptional and translational events. Our data indicate that nuclei assembled in vitro are capable of initiating early steps of nucleologenesis but that the resulting PNBs are unable to fuse with each other, probably due to the absence of a functional nucleolus organizer. With appropriate modifications, this experimental system should be useful to define and analyze conditions promoting the site-specific assembly of PNBs into a coherent nucleolar body.

Animals↗
PubMed1992

Familial Conn's syndrome.

We describe the occurrence of primary hyperaldosteronism in two sisters. Although this is only the second published report of familial Conn's syndrome, it does have implications for the relatives of patients with Conn's syndrome and these are discussed.

Adenoma↗
PubMed1991

Donor-recipient age difference--an independent risk factor in cyclosporin-treated renal transplant recipients.

Whilst HLA matching is routine in renal transplantation the possible benefits of matching donor to recipient age have not been previously explored. The simultaneous effect on graft survival of donor and recipient age was therefore investigated for 274 consecutive first cadaver transplant recipients treated by cyclosporin immunosuppression in two centres. The overall graft survival was 77%, and was not significantly different between the two centres. Individually there was no significant effect of donor or recipient age but taken together, the difference in age significantly affected graft survival (P less than 0.01) regardless of the mode of failure. The 1-year graft survival for all failures was 66.2% when the donor was 5 or more years older. 84.5% when the donor was 5 or more years younger and 71.7% when the donor was within 5 years of the recipient's age. Multivariate analysis, taking into account other variables (HLA matching, dialysis time and type, donor/recipient sex, local/imported kidneys, sensitivity, operation time, total ischaemic time, pre-operative transfusions) indicated that age difference was the single most important variable (P less than 0.01). The only other important covariate risk factor in improving graft survival was HLA-DR matching (P less than 0.05). Donor-recipient age difference is a potentially important recipient selection criterion in cyclosporin-treated renal transplant patients.

Adolescent↗