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Biomedical subjects

H Falk

Publications and source records attributed to H Falk.

At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

An interactive computer simulation program for the design of statistical control procedures in clinical chemistry.

A computer simulation program has been developed to aid in the design of statistical quality control procedures in clinical chemistry. This 'QC simulator' permits the user to study the effects of parameters in the analytical procedure (method standard deviation, components of variance, rounding of data) and parameters in the control procedure (choice of statistics, control limits, decision criteria, number of control observations). The performance of the control procedures being studied are characterized by their probability for ejection, estimated at several different levels of random and systematic error, and presented by plots of statistical power vs the size of the analytical errors. The relative performance of different control procedures can be compared based on these performance characteristics. Another important application of the program is in the design of control procedures to assure that a specified level of analytical quality is achieved in routine laboratory analyses. The utility of this interactive simulation tool is illustrated in two typical sample runs.

Chemistry, Clinical↗
PubMedDate not supplied

Mount St. Helens eruptions: the acute respiratory effects of volcanic ash in a North American community.

After the May 18, 1980 volcanic eruption of Mount St. Helens, increases were observed in the number of patients who, because of asthma or bronchitis, sought medical care at emergency rooms of major hospitals in areas of ashfall. An interview study of 39 asthma and 44 bronchitis patients who became sick during the 4 wk following the eruption and who attended the emergency rooms of two major hospitals in Yakima, Washington, and of healthy matched controls indicated that a history of asthma, and possibly of bronchitis, were risk factors for contracting respiratory problems. The interview study also indicated that the main exacerbating factor was the elevated level of airborne total suspended particulates (in excess of 30,000 micrograms/m3) after the eruption. An interview study of 97 patients who had chronic lung disease and who lived in the same area as the above-mentioned patients, but who did not go to a hospital, showed that the ashfall exacerbated the condition in about one-third of these. Emergency planners and their geologist advisers should be aware that special preventive measures are justified for people with a history of asthma or chronic lung disease who live in communities at risk to volcanic ashfalls.

Adolescent↗
PubMedDate not supplied

Cancer and birth defects near the Drake Superfund site, Pennsylvania.

The Drake Superfund site in Clinton County, Pennsylvania, has been contaminated with the carcinogens beta-naphthylamine, benzidene, and benzene. The authors reviewed county-wide, age-adjusted, sex-, race-, and site-specific cancer mortality rates for the years 1950-1959, 1960-1969, and 1970-1979, and type-specific birth defects incidence rates for 1973-1978. During the 1970s, a significantly increased number of bladder cancer deaths occurred among white males in Clinton County, and a significantly increased number of other cancer deaths occurred in the general population of Clinton and three surrounding counties. There were no statistically significant clusters of any specific birth defect or of all birth defects. County-wide data on cancer and birth defects can be used for initially screening counties with Superfund sites, but more definitive studies are needed to assess the actual health effects caused by these sites.

Age Factors↗
PubMedDate not supplied

A pilot epidemiologic study of possible health effects associated with 2,3,7,8-tetrachlorodibenzo-p-dioxin contaminations in Missouri.

In 1971, 2,3,7,8-tetrachlorodibenzodioxin (TCDD)-containing waste oils were sprayed for dust control on residential, recreational, and work areas in Missouri. In several of these areas, the magnitude and the extent of this environmental contamination were not known until late 1982 or 1983. In the first phase of the investigation, a group of persons considered to be at highest risk of exposure and an appropriate comparison group were selected from reviews of Health Effects Survey screening questionnaires. These persons received complete medical examinations and a series of laboratory tests focused on detecting presymptomatic effects in key target organ systems (i.e., hepatic, dermatologic, immunologic, and neurologic effects). Comparisons of these two groups did not produce any firm indications of increased disease prevalence directly related to the putative exposures; of significance is the fact that no cases of chloracne or porphyria cutanea tarda were seen. Nevertheless, no overall definitive conclusion should be based just on this initial pilot study. Insights were provided that are being examined in more refined epidemiologic studies using different designs and strategies--especially of larger, more homogeneous population groups in which exposure status can be better characterized--focused primarily on discerning any potential effects on the urinary tract, liver, neurological, and immune systems. Concurrently, research into the development of replicable laboratory analytical methods and reference ranges for measuring TCDD body burden are being pursued.

Adolescent↗
PubMedDate not supplied

Purification of murine and feline type-C virus envelope polypeptides as micellar protein complexes.

A technique originally described for the isolation of Friend leukaemia virus envelope polypeptides [1] yields equivalent structures from Moloney leukaemia. AKR and BALB/c xenotropic virus as well as feline leukaemia virus. The envelope polypeptides are obtained as micellar protein complexes, named rosettes. Rosettes of the five mammalian type-C viruses examined are indistinguishable by electron microscopy. Separation of these aggregates in polyacrylamide gel electrophoresis under nonreducing conditions reveals a glycoprotein of about 85000 d as their major component. Tryptic peptide analyses identify the viral origin of these polypeptides and emphasize strain specific differences in their primary structure.

Animals↗
PubMedDate not supplied

The public health response to 2,3,7,8-TCDD environmental contamination in Missouri.

In 1971, waste oil containing 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was sprayed for dust control on a number of residential, recreational, and work areas in Missouri. In several of them, the level and extent of environmental contamination were not known until late 1982 or 1983. Extrapolation from existing toxicological data indicated the potential for substantial adverse health effects in highly exposed populations. As a result, the Missouri Division of Health and the Centers for Disease Control initiated close collaboration with the Environmental Protection Agency (EPA) on review and evaluation of environmental data, the development of health advisories to EPA on the need for remedial or preventive actions at specific contaminated sites, a health education effort for the medical community and general public, establishment of a dermatological screening clinic, establishment of a central listing of potentially exposed persons through administration of a health effects survey questionnaire, and a pilot medical study of a "highest risk" cohort. Strategies for additional interventions will continue to be based on findings derived from this first phase of the investigation.

Animals↗