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Biomedical subjects

E Barnett

Publications and source records attributed to E Barnett.

At least 19 recordsLinked to original sources
PubMed1992

Geographic and socioeconomic variation in the onset of decline of coronary heart disease mortality in white women.

BACKGROUND: Regional, metropolitan, and socioeconomic factors related to the onset of decline of coronary heart disease (CHD) mortality among White women are reported. Such studies are important for planning population-level interventions. METHODS: Mortality data for 1962 to 1978 were used, to estimate the year of onset of decline. Ecological analyses of socioeconomic data from the US census were used to emphasize structural and organizational aspects of changes in disease, rather than as a substitute for an individual-level design. RESULTS: Onset of decline of CHD mortality among White women was estimated to have occurred by 1962 in 53% of 507 state economic areas (SEAs), ranging from 79% in the Northeast to 39% in the South. Metropolitan areas experienced earlier onset of decline than did nonmetropolitan areas. Average income, education, and occupational levels were highest in early onset areas and declined across onset categories. CONCLUSIONS: The results provide additional evidence for previously observed geographic and social patterns of CHD decline. Emphasis on structural economic factors determining the shape of the CHD epidemic curve does not detract from the medical importance of risk factors, but underscores the importance of community development to public health improvements. The results are consistent with the idea that the course of the CHD epidemic in the United States has been strongly influenced by socioeconomic development.

Adult↗
PubMed1990

Splenic responses to acute insulin-induced hypoglycaemia in humans.

1. The effects of acute hypoglycaemia on the spleen were examined in normal humans using radioisotopic techniques, complemented by ultrasonic examination of the spleen. Hypoglycaemia had a modest effect on splenic area, measured by ultrasonography, which declined to 62 +/- 6% (mean +/- SEM) of the basal value after the onset of the acute hypoglycaemic reaction. 2. Hypoglycaemia had a pronounced effect on the splenic radioactivity, which decreased significantly to a mean of 10 +/- 7% of basal radioactivity at 15 min after the onset of hypoglycaemia. The splenic image completely disappeared at some time after hypoglycaemia in all subjects. 3. The reduction of splenic radioactivity was abolished during non-selective alpha-adrenergic blockade with phentolamine, but was unaffected by beta-adrenergic blockade with propranolol, or cholinergic blockade with atropine, which suggests that the response of vessels perfusing the spleen is mediated by alpha-adrenoceptors.

Adult↗
PubMed1990

Evaluation of a new high-efficiency blood warmer for children.

Because currently available blood warmers are inadequate for infants and children requiring massive transfusion, the performance of a new high-efficiency pediatric blood warmer (System 250TM, LEVEL 1 Technologies Inc., Marshfield, Massachusetts) was evaluated and compared with a commonly used conventional blood warmer (Model DW1000A, American Pharmaseal, Valencia, California). Cold (5-6 degrees C), diluted red blood cells (RBC) (Hct = 30%) were infused through the warmers over a series of flow rates, and the resulting temperatures of the infusate were measured. The flow rates of diluted packed RBC were also measured over a series of infusion pressures. At a flow rate of 225 ml/min, the output temperature of the System 250TM was 33.6 degrees C compared with 24.6 degrees C (P less than 0.05) for the conventional warmer. Above a flow rate of 250 ml/min, however, the water bath of the System 250TM cooled significantly, resulting in a deterioration of performance and an output temperature of only 24.2 degrees C at a flow rate of 400 ml/min. With a 16-G catheter attached, the flow rate at a pressure of 300 mmHg was 223 ml/min through the System 250TM compared with 160 ml/min (P less than 0.05) for the conventional warmer. The System 250TM produced higher output temperatures and a lower resistance to flow compared with the conventional warmer, but flow rates of cold blood through the System 250TM should be restricted to 250 ml/min or less to ensure adequate warming.

Blood Transfusion↗
PubMed1984

Human auto-antiidiotypes regulating T cell-mediated reactivity to tetanus toxoid.

While investigating the effect on B cells of repetitive in vivo immunization with tetanus toxoid (TT), we observed the subsequent development of specific anergy for T cell delayed hypersensitivity (DTH) to TT. This appeared approximately 35 d after a series of five booster immunizations. Concurrently, in vitro T cell blastogenic responses were preserved. Serum obtained when the skin tests were nonreactive demonstrated a profound inhibitory activity on T cell reactivity. This activity was shown to be anti-antibody activity that was both anti-F(ab)'2 and, specifically, anti-TT F(ab)'2. It blocked binding of TT to a pool of allogeneic antibodies and also inhibited allogeneic antigen-specific T cell blastogenesis. Thus, we could identify activity in the serum of hyperimmunized individuals that appeared auto-anti-idiotypic (anti-id) and represented a single or family of major crossreacting idiotypes (id) for TT. The expression of the auto-anti-id correlated with the loss of T cell reactivity in vivo and in vitro. Subsequent examinations revealed persistent, specific cutaneous anergy beyond six months, which was then associated with a failure of T cells to react with antigen in vitro. Mixing experiments with cells from these later times and cryopreserved autologous cells obtained prior to hyperimmunization revealed there had been the development of antigen-specific T suppressor cells. Thus, in vivo DTH tolerance following hyperimmunization was associated with an inhibitory serum activity that appeared to be anti-id. Persistence of tolerance (greater than 6 mo) occurred with the development of T suppressor cells.

Adult↗
PubMed1982

Ultrasonic characterisation of diffuse liver disease - the relative importance of frequency content in the A-scan signal.

Successful methods of ultrasonic characterisation of alcohol-induced diffuse liver disease using texture analysis (Lerski et al. 1979, 1980a, b) have studied the radiofrequency (RF) A-scan ultrasonic signal. In the present paper the Fourier spectra of such signals have been partitioned and a statistical analysis implemented to determine the diagnostic usefulness of certain frequency groups present in the signal. Although this method has not, of itself, been found to compared favourably with texture analysis it has shown that useful information is present in the high frequency portion of the frequency spectra. This information would not be available if the smoothed and denodulated A-scan signal were studied.

Fatty Liver, Alcoholic↗
PubMed1975

Ultrasound in the diagnosis of fluid collections following renal transplantation.

Ultrasound examinations of the pelvis and kidney have been carried out following 68 renal transplants. In 16 patients moderate sized or large perirenal or pelvic fluid collections were demonstrated. The composition of the fluid was lymph in seven cases, pus in four, blood in three and urine in two. Ten of these 16 patients had clinical features compatible with a pelvic fulid collection while six had no such localising features. We have found ultrasound to be extremely valuable in the diagnosis and precise localisation of pelvic fulid collections following transplantation, often at a stage before pressure effects and symptoms have appeared. It also provides a rapid and reliable means of excluding a pelvic or perirenal abscess in the pyrexial patient.

Abscess↗
PubMed1975

Ultrasound in the staging of bladder tumours.

The ultrasonic features of 162 bladder tumours are described. Comparing clinical staging by the TNM system and the ultrasonic appearances, there is a high degree of accuracy in staging by ultrasound. The use of this painless non-invasive technique is assessed and should be used in staging bladder tumours only in conjunction with other established methods, and not in isolation.

Cystoscopy↗