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Biomedical subjects

M Neuberger

Publications and source records attributed to M Neuberger.

54 records · Page 3Linked to original sources
PubMed1984

Carbon monoxide uptake and the resulting carboxyhemoglobin in man.

In order to calculate the carboxyhemoglobin concentration in human blood under various circumstances and for particular groups or individuals, the model proposed originally by Coburn and coworkers in a slightly revised form was tested. The relevant breathing parameters were measured as minute averages and used for computation of COHb time course. At the same time blood samples were taken and analysed for carboxyhemoglobin. For four different subjects, various breathing conditions and work rates the average deviation of experimental data from theoretical predictions is 7.4%. Some data are presented graphically. Excellent conformity of all the results indicate, that the model is suitable to show the influence of most physiological and breathing parameters on the dynamics of carbon monoxide uptake.

Adult↗
PubMed1984

[Heavy metals--toxicity at low doses in the environment and in the work place].

Ecotoxicity of heavy metals is related to their persistence, accumulation and dispersion tendency. Sources, pathways of exposure and adverse health effects of low doses are reviewed. Environmental and occupational toxicity of lead, cadmium and mercury compounds are discussed and the carcinogenic and sensitizing effects of chromium compounds as an example of a heavy metal which is essential in low doses. High risk groups, most susceptible target organs, early symptoms, signs of subclinical poisoning, numbers of diseases from heavy metals accepted in Austria as occupational diseases and environmental hazards are summarized.

Air Pollution↗
PubMed1983

[Different selection rates--fallacies in epidemiological studies].

Practical examples from preventive and curative medicine are given to demonstrate how competing selection rates distort the results of epidemiological studies. In order to quantify this distorsion the bias is tabulated and graphed for different combinations of features (diseases, symptoms, findings, etc.) on the one hand and different admission or participation rates on the other hand. With the help of a formula which can be stored in a pocket calculator the sample bias can be quantified also. Prerequisite is the estimation of selection rates. They have such a bearing on the results of epidemiological studies that it is advisable to ask two questions before any interpretation: 1. which factors can lead to different admission rates in the groups (A,B) under study and 2. which factors can lead to different admission rates of persons with and without the feature (X) under study.

Asbestosis↗
PubMed1982

[Carbon monoxide in mother and newborn infant from smoking during pregnancy].

COHb-values of 24 newborn infants investigated (cord blood) were higher altogether than the corresponding maternal concentrations (venous) at birth. COHb in percent of saturable Hb ranged from 0.3 to 0.7 in 10 infants of nonsmokers and from 0.8-11.9 in 14 infants of smokers. Correlations between maternal and infant COHb were statistically significant. At birth the mean infant/maternal COHb ratio was 2.5. The significant correlations between maternal COHb during pregnancy (32.-38. week) and infant COHb at birth (cord blood) is an indication for the predictive value of such tests.

Carbon Monoxide↗
PubMed1980

Comparison of lung cancer risks for dust workers, asbestos-cement workers and control groups.

In a prospective study, 1630 men exposed to dust for long periods (foundry workers and workers in metal, ceramics, glass, stone and other industries) and 1630 controls not exposed to dust were registered between the years 1950 and 1960; the population comprised workmen living in Vienna and born in 1910 or before. Controls were matched according to age and smoking habits. Causes of deaths were followed up to 1976 from official death certificates, mainly issued by hospitals with routine autopsy. General mortality was higher in the dust-exposed group, and there was a significant excess of deaths from lung cancer: 1.5 times higher than that for controls, 1.6 times higher than that for other Viennese men of the same age and 2.1 times higher than that for Austrian men. There were no excess deaths from lung cancer up to the age of 60. It is evident that only long exposure times raise the lung cancer risk for dust-exposed workers. In a historical prospective study of asbestos-cement workers and control groups, using the same criteria of sex, age and exposure time, the preliminary data show an age-standardized relative risk of 1.5 for asbestos-cement workers compared with cement workers, but no excess risk in comparison with the local and general population.

Age Factors↗
PubMed1979

[Silicotuberculosis in Austria and the industrial injuries act (author's transl)].

The case material comprising all persons who developed silico-tuberculosis since it was listed as an occupational disease almost 50 years ago is analysed. The relationship between various occupations and the incidence of silicosis is reviewed with special reference to the most exposed group: the wokers in the granite quarries of Upper Austria. The changes in the clinical picture of the lesion, legal aspects, diagnostic difficulties in distinguishing between silicosis with or without complicating tuberculosis are discussed.

Adult↗
PubMed1978

[Endemic pleural plaques and environmental factors (author's transl)].

In an agricultural town in Burgenland (Austria) we found an increased prevalence of pleural plaques. These calcifying thickenings of the pleura are related to minimal asbestos exposure such as is mesothelioma, but they cannot be regarded as a precancerosis. The increased occurrence of pleural plaques in this town of nearly 3500 inhabitants (in which during 1916 to 1945 asbestos was mined) we first found at the chest x-ray archives of a pulmologic hospital, then by mass radiography and blind comparison with control groups. A photofluoroscopy of 300 persons yielded 16 cases with definite pleural plaques (5.3%) among which were 4 cases with suspected asbestosis and another 14 cases with uncertain pleural plaques (4.7%). The 600 control persons showed no such radiological changes. Interviews wich persons detected for pleural plaques at mass radiography gave no indication that they had occupational asbestos exposure. But asbestos was detected in the soil of vineyards and in the dust of the houses. Asbestos was also detectable in the atmospheric dust by x-ray diffraction and scanning electron microscopic techniques.

Asbestos↗
PubMed1976

[A rapid carboxyhemoglobin determination by means of non-dispersive ultra-red gas analysis (author's transl)].

A rapid and reliable method of carboxyhemoglobin determination is described. Hemoglobin-bound carbon monoxide is released chemically into a continuous nitrogen stream and transported to an infrared gas analyser. The total amount of released CO is determined electronically. 100% CO Hb values are obtained in the same way from diluted blood samples after flushing with pure CO in special saturation vessels. The method described yields results with a standard deviation of +/- 2.5%.

Carbon Monoxide↗
PubMed1975

Identification of a deoxyribonuclease implicated in genetic transformation of Diplococcus pneumoniae.

A mutation of Diplococcus pneumoniae, end-1, reduces the major deoxyribonuclease activity of the cell, an endonuclease, to 10% of its normal value without impairing transformation. Further mutations, called noz, abolish the residual endonuclease activity and block transformation. The residual endonuclease is similar to the wild-type enzyme in size, charge, divalent cation dependence, inhibition by ribonucleic acid, and formation of oligonucleotide products. However, the mutant endonuclease is more temperature sensitive, which suggests that the end-1 mutation occurred in a structural gene for the enzyme. Genetic analysis showed that the noz mutations occur at the same genetic locus. A number of new end mutants were analyzed. Those that retained more than 1.4% of the normal endonuclease activity were essentially normal in transformation; those with less than 1% were defective. The transformation-defective end mutants appear to be blocked in the entry of deoxyribonucleic acid (DNA) since they carry out the prior step of binding DNA to the outside of the cell. The major endonuclease of the cell may act as a DNA translocase by attacking and degrading one strand of DNA, thereby facilitating entry of the complementary strand into the cell.

Cations, Divalent↗
PubMed1975

Membrane location of a deoxyribonuclease implicated in the genetic transformation of Diplococcus pneumoniae.

The cellular localization of enzymes in Diplococcus pneumoniae was examined by fractionation of spheroplasts. A deoxyribonuclease implicated in the entry of deoxyribonucleic acid (DNA) into the cell during genetic transformation was located in the cell membrane. This enzyme, the major endonuclease of the cell (endonuclease I), which is necessary for the conversion of donor DNA to single strands inside the cell and oligonucleotides outside, thus could act at the cell surface. Another enzyme, the cell wall lysin (autolysin), was also found in the membrane fraction. Other enzymes, including amylomaltase, two exonucleases, and adenosine triphosphate-dependent deoxyribonuclease, and a restriction type endonuclease, were located in the cytosol within the cell. None of the enzymes examined were predominantly periplasmic in location. Spheroplasts were obtained spontaneously on incubation of pneumococcal cells in concentrated sugar solutions. The autolytic enzyme appears to be involved in this process. Cells that were physiologically competent to take up DNA formed osmotically sensitive spheroplasts two to three times faster than cells that were not in the competent state. Although some genetically incompetent mutants also formed spheroplasts more slowly, other such mutants formed them at the faster rate.

Cell Fractionation↗
PubMed1974

Role of a deoxyribonuclease in the genetic transformation of Diplococcus pneumoniae.

Two steps in the uptake of DNA by Diplococcus pneumoniae were characterized by analyzing mutants defective in transformation. A strain deficient in the two major deoxyribonucleases of D. pneumoniae takes up DNA normally and converts it to single strands within the cell and oligonucleotide fragments outside the cell. Extracts of this strain contain a residual deoxyribonuclease that produces similar oligonucleotide fragments in vitro. This enzyme is missing in transformation-defective mutants blocked in the second or entry step. Cells of this mutant class bind large amounts of DNA to their surface in a form accessible to external agents. Another class of nontransformable mutants fails to bind DNA at all. Their deoxyribonuclease content is unchanged, and they are apparently blocked in the first or binding step of DNA uptake. The binding step requires a source of energy and prior activation of the cells by competence factor. Entry may be independent of these requirements and may come about by action of the deoxyribonuclease on one strand of DNA with energy for the transport of the intact strand deriving from hydrolysis of the degraded strand. The enzyme may thus act as a DNA translocase.

Binding Sites↗
PubMedDate not supplied

Environmental asbestos exposure and cancer mortality.

From 1970 to 1980, mortality from cancer of the lung and stomach was analyzed in a town with asbestos deposits and in a town with asbestos processing. The populations of the entire country, the province, the district, and of all communities of the same size and agricultural index were used as references. In the town with asbestos contamination of air and water from natural tremolite deposits and an endemic occurrence of pleural plaques, no increased risk for lung or stomach cancer was found. In the town with asbestos cement production lung cancer rates were lower in males and higher in females, and stomach cancer rates were lower than expected. No significant differences could be attributed to environmental asbestos exposure.

Asbestos↗
PubMedDate not supplied

[The influence of smoking on uteroplacental blood flow and maternal carboxyhemoglobin levels].

The effect of nicotine consumption on uteroplacental blood flow and on the carboxyhemoglobin concentration in maternal serum was examined in 20 pregnant women. It was found that poor uteroplacental circulation is more frequent in women who smoke than in those in whom placental insufficiency is suspected. Normal circulation of Type I was only recorded in gravidae smoking not more than 10 cigarettes a day. Determination of the carboxyhemoglobin concentration in the maternal serum as an indicator of the overall level of contamination by tobacco smoke revealed a significant correlation of the morning value with the placental blood flow type. The average birthweight of the newborns of smokers was 300 g lower than might have been expected. In isolated cases chronic nicotine abuse led to intra-uterine growth retardation, with no other apparent causes of placental insufficiency.

Adult↗
PubMedDate not supplied

Moderate carbon monoxide exposure during sleep: neuro- and psychophysiological effects in young and elderly people.

In order to assess age-related effects of carbon monoxide (CO) on brain wave-activity and sleep, auditory evoked potentials (AEP) were measured during sleep in 10 healthy young volunteers (20-25 years) and in a group (N = 10) of healthy elderly Ss (55-72 years) under control- and exposure-conditions in counterbalanced order. Sleep-stages were classified according to the Rechtschaffen and Kales scoring-system. In addition to electrophysiological measures memory-performance and subjective feeling (mood-scale) was assessed before and after sleep. Eight hours of CO-exposure (100 ppm) gave rise to about 8% COHb. In the group of young Ss there was a significant (p less than 0.05) increase of deep sleep (stages 3,4), and a decrease of stage REM-sleep during CO-exposure, whereas in elderly Ss similar but non-significant sleep-changes occurred. Some CO-related AEP-changes within different sleep-stages, namely shorter latencies in elderly Ss and higher amplitudes in young Ss, approached significance. Within the group of young Ss there was a tendency to more depressed mood after CO-exposure, as well as to CO-related impairment of memory consolidation; no such effects were observed in elderly Ss. The general hypothesis of more pronounced CO-susceptibility of elderly people was, therefore, not supported in this study.

Adult↗