Search PubMed⌕ Search

Biomedical subjects

R R Engel

Publications and source records attributed to R R Engel.

105 records · Page 6Linked to original sources
PubMed1972

Carbon monoxide production from heme compounds by bacteria.

Carbon monoxide formation from heme compounds by bacteria was investigated to study microbial hemoprotein catabolism with reference to heme degradation by mammalian tissues. Hemolytic and nonhemolytic bacteria were incubated aerobically and anaerobically with the following substrates: erythrocytes, hemoglobin, myoglobin, cytochrome c, hematin, iron hematoporphyrin, copper hematoporphyrin, protoporphyrin, and bilirubin. After 18 hr at 37 C the evolved CO was measured by gas chromatography. None of the bacteria formed CO anaerobically. Under aerobic conditions both alpha-hemolytic Streptococcus mitis and hemolytic Bacillus cereus formed CO from all of the heme compounds tested, whereas nonhemolytic Streptococcus mitis did not evolve CO from any of the substrates. The hemolytic bacteria did not produce CO when the iron of heme was either replaced by copper or removed, as in copper hematoporphyrin and in protoporphyrin, respectively.

Aerobiosis↗
PubMed1971

Factors influencing pulmonary methane excretion in man. An indirect method of studying the in situ metabolism of the methane-producing colonic bacteria.

Measurements of pulmonary excretion of methane (CH(4)) were used to obtain information on the CH(4)-producing bacteria in man. Preliminary studies indicated that (a) all CH(4) excreted by man is produced by colonic bacteria, (b) there is no appreciable utilization of CH(4) by man, and (c) breath CH(4) can serve as a relatively accurate indicator of CH(4) production in the intestine. The rate of pulmonary CH(4) excretion varied enormously, ranging from undetectable (<5 x 10(-6) ml/min) to 0.66 ml/minute. In general, the CH(4) excretion rate for subjects was consistently very low (nonproducers) or relatively large (producers). 33.6% of the adult population were producers of CH(4). Whereas diet, age over 10 yr, and sex did not influence the rate of CH(4) production, some familial factor appeared to play an important role. 84% of siblings of CH(4) producers also were producers, while only 18% of the siblings of nonproducers were found to be CH(4) producers. This familial tendency appeared to be determined by early environmental rather than genetic factors. These studies of CH(4) excretion demonstrate that the exposure of individuals to intestinal bacterial metabolites may differ markedly and that these differences may be chronic and determined by familial factors.

ABO Blood-Group System↗
PubMedDate not supplied

Arsenic in drinking water and mortality from vascular disease: an ecologic analysis in 30 counties in the United States.

Chronic arsenic consumption can cause vascular diseases. Adverse vascular effects of arsenic in drinking water in the United States have not been studied. This study investigated the ecological relationship between the population-weighted mean arsenic concentration in public drinking water supplies and mortality from circulatory diseases in 30 U.S. counties from 1968 to 1984. Mean arsenic levels ranged from 5.4 to 91.5 micrograms/l. Standardized mortality ratios (SMRs) for diseases of arteries, arterioles, and capillaries (DAAC) (ICD 8th/9th revision, 440-448) for counties exceeding 20 micrograms/l were 1.9 (90% confidence interval [CI] = 1.7-2.1) for females and 1.6 (90% CI = 1.5-1.8) for males. The SMRs for the three subgroups of DAAC--arteriosclerosis, aortic aneurysm, and all other DAAC--tended to be elevated. With respect to the same arsenic group, the SMRs for congenital anomalies of the heart (ICD-8/9, 746/745-746) and circulatory system (ICD-8/9, 747) also tended to be elevated. Two competing interpretations emerge as possibilities: either there are spurious associations resulting from invalid outcome data or causal associations.

Adult↗
PubMedDate not supplied

[Quantification of dementia-related disabilities in daily behavior with the DAFS (Direct Assessment of Functional Status): reliability and validity of a German test version].

The DAFS (Direct Assessment of Functional Status) is a new test for the assessment of competence of demented patients in situations of everyday life. The present study assesses objectivity, temporal stability, concurrent and discriminative validity of a German version of the DAFS. Sixteen patients with a DSM-III-R-diagnosis of dementia of the Alzheimer's type, 8 of which with a mild (MMSE 18-25) and 8 with a moderate (MMSE 12-17) dementia, and 8 control subjects without any symptoms of dementia (MMSE 28-30), matched with the patient groups in age, gender and education, were assessed three times within 3 weeks with the DAFS and once with the NOSGER (an ADL rating scale). The DAFS showed high objectivity (correlation between two test administrators r = .97) and stability (2 week retest reliability r = .98) and was able to discriminate significantly between the study groups and with a strong effect size. Correlations with the total score and the IADL subscale score of the NOSGER were high (r = .81 and r = .86, resp.), whereas correlations with the mood and the disturbing behavior subscale were much lower (both r = .54). This investigation could demonstrate that the DAFS is an objective, stable and valid test instrument. It has a high power to discriminate between demented and non-demented subjects as well as between various degrees of severity of illness. The test items are highly relevant for everyday functioning and the test itself is a good and necessary addition to the use of ADL or IADL rating scales.

Activities of Daily Living↗