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Biomedical subjects

N F Rodman

Publications and source records attributed to N F Rodman.

At least 19 recordsLinked to original sources
PubMed1994

Predicting the annual concentration of indoor 222Rn from one or more short-term measurements.

Long-term and short-term measurements of indoor 222Rn from 480 houses located in eleven states were used to study the relationship between the annual living area average (ALAA) and 1) a single 2 d measurement and 2) the mean of multiple 2 d measurements (taken in different seasons). Of particular interest is the issue of using a short-term measurement(s) to predict the ALAA in a given house. The results indicate that with 95% confidence (approximately): 1) a single 2 d measurement gives an interval estimate of the true ALAA that is within a factor of 2.5 of the predicted ALAA; and 2) a mean of two 2 d measurements (taken in different seasons) gives an interval estimate that is within a factor of 2.2 of the predicted ALAA. If a more precise estimate of the ALAA is needed, then an alternative procedure to using 2 d measurements should be employed (e.g., measure the annual concentration directly).

Air Pollutants, Radioactive↗
PubMed1994

A performance evaluation of bare alpha track detectors.

Bare alpha track detectors are sensitive to radon progeny as well as to radon gas. This paper reports the test results for two brands of bare alpha track detectors that received several radon exposures at three progeny concentrations. The results show a relationship that is a linear combination of both the radon gas and the radon progeny concentrations. The reported radon concentration depended on the equilibrium factor assumed by the processor. The sensitivity of bare alpha track detectors increases with altitude, but this is a minor, correctable effect compared to the equilibrium factor.

Evaluation Studies as Topic↗
PubMed1992

Indoor 222Rn concentrations in a probability sample of 43,000 houses across 30 states.

The U.S. Environmental Protection Agency has assisted 30 of the 48 conterminous states in completing statistically designed surveys of indoor 222Rn over the past 4 y. In all states, the lowest livable level of 43,054 randomly selected houses was tested using charcoal canisters exposed for 48 h. The sampled population included owner-occupied ground-level houses having listed telephone numbers. Summary statistics along with the percentage of houses exceeding various concentration levels are given by state and over all states for houses with basements, for houses without basements, and for all houses. As expected, 222Rn concentration varies widely from one state to another and, in every state, basement houses exhibit higher concentrations than nonbasement houses. The lognormal distribution is shown to be a good approximation to the distribution of screening measurements over the 30-state area. There is, however, some evidence that the lognormal distribution underestimates, by a narrow margin, the upper tail of the observed distribution of basement measurements.

Air Pollutants, Radioactive↗
PubMed1985

Lung carcinoma by histologic type in coal miners.

Histologic types of lung carcinoma were studied in 171 coal miners in the National Coal Workers' Autopsy Study. These miners had an average underground mining tenure of 29 +/- 14 years and an average smoking history of 31 +/- 23 pack-years. The proportion of carcinomas by cell type were: squamous cell carcinoma, 30%; adenocarcinoma, 27%; small-cell undifferentiated carcinoma, 26%; large-cell undifferentiated carcinoma, 9%; and other carcinomas, 8%. More tumors were observed in the right lung and in the upper lobes of both lungs than in the left lung and in the lower lobes of both lungs, respectively. The majority of the tumors were centered on cartilaginous airways (81%) as compared with the peripheral regions of the lung (19%). Squamous cell carcinomas predominated in the older miners and in larger airways. Adenocarcinomas were more common in the peripheral lung. No significant interaction was demonstrated between cell type and years of underground mining. The data indicate that lung carcinoma in coal miners differs little in its pathologic features from men in the general population who smoke cigarettes. No effect of coal mine dust exposure on lung carcinoma histogenesis was demonstrated.

Adenocarcinoma↗
PubMed1976

Gastrointestinal effects of acute ferrous sulfate poisoning in rats.

Ferrous sulfate administered intragastrically to rats produced two types of intestinal lesions: corrosive injury to the stomach and upper part of the small intestine, and ileal infarcts associated with venous thrombosis in some animals given fatal doses. Iron was deposited at the interface of viable and necrotic mucosa and in blood vessels of all layers. By means of electron microscopy the iron deposits were located in the basement membrane of the vessels. Fatal doses were always associated with intestinal injury, although the time of death suggests that death was caused by absorption of iron rather than by the local injury.

Animals↗
PubMed1974

Venous thrombosis on prosthetic surfaces. Evolution and blood coagulation studies in a nonhuman primate model.

Thrombi deposited on prosthetic devices in the superior vena cava of the rhesus monkey were studied by morphologic and biochemical technics. Glass or silicone-coated glass (SCG) rings were implanted for 30 minutes to 14 days. Thrombus was deposited on the surface of each prosthetic device, and deposition was much greater and more rapid on glass surfaces than on SCG surfaces. On SCG surfaces, initial deposits consisting of single platelets, small platelet aggregates and erythrocytes were seen by scanning electron microscopy. These were followed by larger platelet aggregates, fibrin and, much later, leukocytes. Transmission electron micrographs revealed disintegration of the platelets forming aggregates and an osmiophilic deposit on the prosthetic surface. Shortened partial thromboplastin times were observed in all test animals but the sham-operated one, and therefore may be predictive of thrombus formation.

Animals↗
PubMed1972

Reactions of blood with nonbiologic surfaces. Ultrastructural and clotting studies with normal and coagulation factor deficient bloods.

Interaction of normal and coagulation factor deficient bloods with glass, Teflon and silicone-coated glass surfaces have been studied. The morphology of the blood-surface interaction was observed by scanning electron microscopy. Activation of the intrinsic coagulation system and progression of these changes, monitored by use of the partial thromboplastin time test, were influenced by both the type of surface to which blood was exposed and the deficiencies of coagulation Factors I, VIII, IX, or XII. Deficiency of fibrinogen appears to enhance, minimally, activation of the coagulation sequences by test materials. However, deficiency of fibrinogen markedly reduces adhesion of platelets to foreign surfaces. Deficiency of Factor XII, but not of Factors VIII or IX, decreases platelet adhesion to nonbiologic surfaces but to a lesser extent than does deficiency of fibrinogen. Roughness of test surfaces appears to encourage cellular deposition from blood. An ex vivo model designed for screening materials for their compatibility with blood is described.

Adult↗
PubMed1971

Effect of a new antiaggregating chemical on the structure and function of the human platelet.

A new antiaggregating chemical, alpha-(p-(fluoren-9-ylidenemethyl)phenyl)-2-piperidineethanol (RMI 10,393), designated FYPE, was found to be an effective inhibitor of platelet aggregation induced by adenosine diphosphate (ADP), thrombin, collagen, or epinephrine. Effects of the antiaggregant on platelets were concentration dependent. Aggregation was prevented by low concentrations of FYPE that produced in the platelet only minor ultrastructural changes consisting of loss of microtubules and of discoid shape. Low levels of FYPE that prevented platelet aggregation had no effect on platelet ATPase activities but did alter clot retraction, the thrombin-induced shift in electrophoretic mobility and platelet cholinesterase activity. Market decrease in ADP release and increase in adenyl cyclase activity were produced by low levels of FYPE. This study provides a model for evaluation of platelet antiaggregating compounds in vitro.

Adenosine Diphosphate↗