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Biomedical subjects

D R Chambers

Publications and source records attributed to D R Chambers.

16 recordsLinked to original sources
PubMed2003

Sudden, unexpected cardiac or unexplained death in England: a national survey.

BACKGROUND: Post-mortem examinations of adults who were apparently healthy but died suddenly and unexpectedly sometimes reveal no morphological abnormalities to explain their deaths. The frequency of such unexplained deaths in relation to other causes of sudden cardiac death is not known. AIM: To estimate the frequency of sudden unexpected cardiac or unexplained death in England. DESIGN: Prospective survey using a stratified random sample of 83 of the 132 H.M. Coroner's jurisdictions in England. METHODS: Consecutive White Caucasians, aged 16-64 years, with no medical history of cardiac disease, seen alive within 12 h of death, on whom autopsy found either a cardiac or no identifiable cause of death, were included. The coroner's officer sent a copy of the post-mortem report and a completed case registration form to the investigators, with tissue samples. RESULTS: Sixty-seven (81%) coroners participated, each maintaining prospective surveillance for 4 months. Of 692 ascertained cases, case registration forms were received for 650 (94%), post-mortem reports for 682 (99%), blood samples for 569 (82%), myocardial slices for 517 (75%) and whole hearts for 47 (7%). In cases with myocardial tissue, death was ascribed to ischaemic heart disease in 465 (82.4%). In 43.1% the ischaemia was acute, in 19.1% there was myocardial scarring but no acute ischaemia, and 20.2% had coronary atheroma only. Death was due to left ventricular hypertrophy in 32 (5.7%), to other cardiac causes in 30 (5.3%) and in 23 (4.1%) there was no clear cause. Those with cardiac causes were 81% male, median ages 55.9 (male) and 56.6 (female) years. The 23 unexplained deaths were 57% female, median ages 40.5 (male) and 54.9 (female) years. The estimated annual frequency of sudden unexpected death due to cardiac or unidentified causes, in English adults of employment age, was 11/100,000 (3481 annual deaths). DISCUSSION: In 4.1% of sudden unexpected deaths under 65 years, no cause was found. Until it becomes accepted practice to identify these cases by a name, such as Sudden Adult Death Syndrome (SADS), it will not be possible to study their aetiology systematically.

Adolescent↗
PubMed2002

In vitro RBC exposure to Plasmodium falciparum has no effect on RBC antigen expression.

Severe malarial anaemia is a leading cause of death in African children younger than 3 years of age who are infected with Plasmodium falciparum. The pathogenesis of this anaemia is not understood. The purpose of this study was to determine if P. falciparum induces changes in RBC membranes that contribute to the immune destruction of RBCs. RBCs were collected from healthy subjects and tested using standard haemagglutination assays for 45 antigens representing 21 blood group systems/collections before and after exposure to P. falciparum, strain FVO. Lectins were used to determine whether crypt or neoantigens were expressed on the RBC membrane. Polybrene was used to detect changes in sialic acid. RBCs were cultured in vitro with and without the parasite, and blinded serologic studies were completed. CD35 (complement receptor 1), CD55 (decay-accelerating factor), CD59 (membrane inhibitor of reactive lysis) and CD47 (integrin-associated protein) flow cytometric assays were compared for infected and uninfected RBCs. The percentage of parasitaemia was determined using Giemsa-stained thin blood films. Two (Ch, Lub) of the 45 antigens had differing strengths of agglutination between infected and uninfected RBCs, but these differences were resolved with a second source of antisera. Forty-three antigens showed no significant differences in the strength of agglutination between the infected and uninfected RBCs. Lectin and polybrene testing showed no differences. CD35, CD55, CD59 and CD47 levels showed no significant differences. P. falciparum does not appear to alter the expression of classified immunogenic antigens on the RBC membrane in this in vitro system. The pathogenesis of the haemolytic episode that occurs in these children remains unclear.

Animals↗
PubMed1989

Inner urban and national suicide rates, a simple comparative study.

The authors have calculated the suicide rate per million for individual causes of death in the Inner North London Coroner's jurisdiction and also a composite rate for all methods of self-destruction. These have been compared with the rates for England and Wales in the years 1979-1985 inclusive. Also calculated has been a total 'non-accidental' death rate comprising all deaths by self-destructive behaviour. For certain causes the two rates are similar but for the remainder there are wide differences. The effect of the law relating to suicide verdicts has been described and its effects discussed.

England↗
PubMed1986

Serotonergic mechanisms in brains of suicide victims.

Serotonergic mechanisms have been investigated in postmortem brain samples from controls and suicide victims. The concentrations of 5-hydroxytryptamine (serotonin; 5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were determined in occipital cortex and hippocampus and the high-affinity binding of ligands to the 5-HT1, 5-HT2 and imipramine-binding sites was assessed in frontal cortex, occipital cortex and hippocampus. The only significant difference between the two groups was a modest increase in 5-HIAA levels in the hippocampus of suicide victims. There was no evidence to suggest that those suicide victims with a clinical history of depression represented a subgroup with altered metabolite levels or binding values. The storage conditions of the samples were not related to the metabolite levels or binding values. There was, however, a significant positive correlation between [3H]imipramine binding and age in some brain regions. The results do not provide any evidence of gross alterations in 5-HT mechanisms in suicide or depression.

Adult↗