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Biomedical subjects

J Claude

Publications and source records attributed to J Claude.

At least 19 recordsLinked to original sources
PubMed2001

Tomato (Lycopersicon esculentum) pectin methylesterase and polygalacturonase behaviors regarding heat- and pressure-induced inactivation.

The combined high pressure/thermal (HP/T) inactivation of tomato pectin methyl esterase (PME) and polygalacturonase (PG) was investigated as a possible alternative to thermal processing classically used for enzyme inactivation. The temperature and pressure ranges tested were from 60 degrees C to 105 degrees C, and from 0.1 to 800 MPa, respectively. PME, a heat-labile enzyme at ambient pressure, is dramatically stabilized against thermal denaturation at pressures above atmospheric and up to 500-600 MPa. PG, however, is very resistant to thermal denaturation at 0.1 MPa, but quickly and easily inactivated by combinations of moderate temperatures and pressures. Selective inactivation of either PME or PG was achieved by choosing proper combinations of P and T. The inactivation kinetics of these enzymes was measured and described mathematically over the investigated portion of the P/T plane. Whereas medium composition and salinity had little influence on the inactivation rates, PME was found less sensitive to both heat and pressure when pH was raised above its physiological value. PG, on the other hand, became more labile at higher pH values. The results are discussed in terms of isoenzymes and other physicochemical features of PME and PG.

Bioreactors↗
PubMed1988

Mortality among German vegetarians: first results after five years of follow-up.

A prospective study of vegetarians recruited from all regions of the Federal Republic of Germany, including West Berlin, was started in 1978 after a preparatory phase of two years in which the cohort was established. The mortality of the 1,904 study participants was evaluated after a follow-up of five years, comparing observed deaths with expected rates based on the national mortality statistics. Of the 858 men and 1,046 women, 89% had followed their diet for at least five years at study entry, the majority of them as strict vegetarians (1,163). By the end of 1983, only 82 persons had died, whereas 219 deaths were expected. In both sexes, the mortality was lowest from cardiovascular diseases [standardized mortality ratio (SMR) for ischemic heart disease about 20] and from cancer (SMR 58 for men, 54 for women). Deaths from diseases of the respiratory and digestive system were also reduced. For individual cancer sites the observed numbers were extremely small, but the risk of dying from lung cancer was significantly reduced; however, deaths from cancers of the colon and rectum, prostate, and breast were rare or even absent. More deaths than expected were observed from stomach, pancreatic, testicular, and brain cancers. An internal comparison of mortality between strict and moderate vegetarians (741) suggests a higher mortality from all causes and malignant neoplasms among strict vegetarians in both sexes, although not statistically significant, and a lower mortality from circulatory system diseases for males. The possible influence of selection factors (e.g., "healthy participant effect," socioeconomic level, and body weight) on the findings of a decreased mortality is discussed together with the role of diet.

Adolescent↗
PubMed1987

Drugs derived from thiazole and imidazole or with nitrogen-carbon-sulphur or tertiary amino groups. Prediction of secondary antithyroid activity by UV/visible spectroscopy.

The chemical structure of various drugs suggests their potential interference with thyroid metabolism by complexing molecular iodine in the thyroid gland. Spectroscopic analysis shows that such compounds form charge-transfer complexes with iodine in a 1:1 stoichiometry. The values of formation constant Kc indicate strong donor-acceptor interactions. Biochemical and histological studies carried out on the rat demonstrated that a correlation exists between the Kc values and the antithyroid activity. A mechanism of action of these molecules on thyroid function is proposed. The potential antithyroid activity of such compounds can therefore be predicted from the Kc values.

Animals↗
PubMed1986

Updating lung cancer mortality among a cohort of man-made mineral fibre production workers in seven European countries.

A historical cohort of 21,967 workers ever employed in 13 European factories manufacturing various types of man-made mineral fibres (MMMF) was observed until 1982. Overall there were 2719 deaths (standardised mortality ratio (SMR) = 111) of which 189 were from lung cancer (SMR = 125). For the glasswool and rockwool/slagwool production subcohorts the lung cancer SMRs rose with time since first exposure, exceeding 170 for the period of 30 or more years. Adjustment for regional variations in mortality substantially reduced the excess in the glasswool group, but not in the rockwool/slagwool. In neither subgroup was there any relationship of lung cancer mortality with length of employment. During the early years of rockwool/slagwool production there was the potential for much higher fibrous dust exposure than at present, because of the absence of dust suppressing oil and/or the use of a batch production process. In addition slag was widely used as a raw material. Amongst workers employed during the early phase, there were 10 lung cancer deaths giving SMRs of 270 and 244 for the periods 20-29 and 30 or more years since first exposure. This group accounts for most of the absolute excess of lung cancer for the rockwool/slagwool plants.

Adult↗
PubMed1986

Association of cancer of the lower urinary tract with consumption of alcoholic beverages. A case-control study.

This preliminary report deals with findings on the consumption of alcoholic beverages (beer, high-proof spirits, wine) and risk of tumors of the lower urinary tract from 340 male patients with urothelial cancer and an equal number of matched hospital controls (age and sex) without any malignant disease. After adjustment for smoking, beer drinkers had an overall increased odds ratio of 1.6 and showed a clear dose-response relationship (odds ratio of 1.2, 2.1 and 2.8 after daily consumption of up to 0.5, 0.5-1.0 and greater than 1 1). Drinkers of high-proof spirits also revealed an elevated odds ratio (of 1.7) compared with abstainers or occasional consumers, as well as increased risks with higher consumption (odds ratios were 1.5 and 2.7 after drinking up to 0.5 and greater than 0.51 per week). No relationship was found with wine drinking. In a multiple logistic regression analysis, only beer consumption showed a significant association.

Alcohol Drinking↗
PubMed1986

Life-style and occupational risk factors in cancer of the lower urinary tract.

In a matched case-control study of cancer of the lower urinary tract in northern Germany in which 340 male and 91 female case-control pairs were interviewed between 1977 and 1982, cigarette smokers were found to have an odds ratio of 2.3 for males and 2.9 for females compared with nonsmokers. A significant dose-response relation was observed for increasing cigarette consumption, and a significant decrease in risk was shown for ex-smokers. Employment in rubber, plastics, dye, textiles, and mining industries was associated with a higher risk, and increased odds ratios were also observed for exposure to spray painting, coal pitch, chromium, and zinc. Controlling for smoking, an elevated risk of 2.3 for drinking more than four cups of coffee per day and significant odds ratios of 2.1 and 2.8 for a daily consumption of 0.5-1.0 liter and above 1.0 liter of beer, respectively, were noted among men. A highly significant odds ratio of 4.0 was found for a daily fluid intake of more than 2 liters. Dietary habits such as the frequent consumption of canned food and fatty meals were associated with a higher risk, whereas a regular consumption of fruits and vegetables was associated with a lower risk. Fourteen determinants found to be important in this case-control series were analyzed by using multiple logistic regression.

Aged↗
PubMed1986

The man-made mineral fiber European historical cohort study. Extension of the follow-up.

The study concentrated on 21,967 workers producing rock wool/slag wool, glass wool or continuous filament in 13 European factories. The expected deaths and incident cancer cases were derived from multiplying the accumulated person-years by national reference rates across sex, age, and calendar-year strata, correction factors for regional lung cancer mortality also being used. Exposure assessment was based on the results of a historical environmental investigation reported elsewhere. There were 189 deaths (151.2 expected), and for rock-wool/slag-wool and glass-wool workers the standardized mortality ratios for lung cancer showed a pattern of increasing mortality with time since first exposure but not duration of employment. There was an excess of lung cancer among rock-wool/slag-wool workers employed during an early technological phase before the introduction of dust-suppressing agents, and fiber exposure, either alone on in combination with other exposures, may have contributed to the elevated risk. No excess of the same magnitude was evident for glass-wool production, and the follow-up of the continuous filament cohort was too short to allow for an evaluation of possible long-term effects. There was no evidence of an increased risk for pleural tumors or nonmalignant respiratory diseases.

Calcium Compounds↗
PubMed1986

Mortality of workers in a German rock-wool factory--a second look with extended follow-up.

A cohort of 2,092 workers employed in a German rock-wool factory was followed until the end of 1982, and the mortality experience was compared with the national mortality rates and the rates of an internal reference cohort. This mortality analysis revealed a standardized mortality ratio (SMR) of 110 for overall mortality. Significantly more malignant neoplasms occurred than were expected (SMR 127). The increase in risk for lung cancer (SMR 121), which was not statistically significant, was also not related to time since first exposure or length of employment. The occurrence of an unusually high SMR of 336 for benign and unspecified neoplasms could not be clarified. Most of the excess from other specific causes of death, such as stomach cancer, pancreatic cancer, and alcoholism, appear to be unrelated to the rock-wool production since they occurred either among workers employed for very short periods (less than one year) or as frequently among workers in the reference cohort.

Construction Materials↗
PubMed1985

Cancer risk of arc welders exposed to fumes containing chromium and nickel.

A retrospective follow-up study among chromium- and nickel-exposed welders, which took into consideration welding procedures, duration of exposure, and smoking habits, yielded an increased cancer risk in a comparison with an internal reference group of turners, milling cutters, and drillers, as well as in a comparison with the general population of the Federal Republic of Germany. Due to the cohort size (1 224 welders, 1 694 turners) and the fact that the observation period is still too short, confirmed statements as to the target cancer sites cannot yet be made. However, it emerges that welding with coated electrodes shows a higher cancer risk as compared to the other welding processes observed. This finding may be explained by the fact that the share of hexavalent chromium compounds in the welding fumes is greater with coated electrodes than with other processes so that a follow-up study observing the health risks of chromium and nickel fumes separately would be warranted. For the confirmation of a more favorable outcome with gas-shielded welding, a larger investigation group or a longer observation period would be required.

Adolescent↗
PubMed1984

Validity of cause of death statements from relatives.

In countries where death certificates are inaccessible for various reasons, cause of death statements made by relatives may gain greater importance. The validity of the cause of death of a deceased family member as stated by relatives compared to the underlying cause as stated on the death certificate has been examined in 310 cases. The sensitivity and the rate of confirmation are highest for neoplasms (both 89.6%). For cardiovascular diseases, the sensitivity (70%) is lower than the rate of confirmation (90%), indicating a certain amount of underreporting. The sensitivity is found to be lowest (50%) for diseases of the respiratory system. Violent deaths, on the other hand, were detected in 93.7%, although confirmed for only 75%. Closer relatives were able to report the cause of death more accurately. The time elapsed since the death of the family member, however, did not affect the recall of the relative. The concrete additional information from relatives, especially for cancer cases, is recommended in the absence of other data sources.

Death Certificates↗
PubMed1984

Telemetry of electrophysiologic variables from conscious dogs: system design, validation, and serial studies.

The necessity for conscious animal models in the study of cardiac physiology has been established for hemodynamics. The characterization of the electrophysiologic properties of the heart has not been performed in a serial fashion in a conscious animal model. Implanted telemetry sensing devices for recording atrial, ventricular, and His electrograms and stimulation systems for both atrium and ventricle allowed serial evaluation of eight dogs for up to 4 months. There were significant fluctuations in some electrophysiologic variables with time, particularly heart rate, sinus node recovery time, and pacing rate for induction of Wenckebach block. This variability did not appear to deviate with time after implantation, and no significant differences in the basal electrophysiologic state were found between the period early after surgery (0 to 2 1/2 weeks) and later (3 to 8 weeks).

Animals↗
PubMed1984

Mortality and incidence of cancer of workers in the man made vitreous fibres producing industry: an international investigation at 13 European plants.

A total of 25 146 workers at 13 plants producing man made mineral fibres (MMMF) in seven European countries (Denmark, Finland, Federal Republic of Germany, Italy, Norway, Sweden, and United Kingdom) were studied in a historical cohort investigation. At 12 of the 13 plants an environmental survey was carried out to determine present day concentrations of airborne man made mineral fibres that showed levels of respirable fibres usually below 1 f/ml and most commonly in the range 0.01 to 0.1 f/ml. Workers were entered into the cohort at the moment of their first employment at one of the 13 factories (which started to operate between 1900 and 1955), and were followed up to at least 31 December 1977. Three per cent of the workers were lost to follow up. National death rates and national cancer incidence rates, where applicable, were used for each of the seven countries for comparison with the workers' cohort. A single death from mesothelioma was reported out of a total of 309 353 person-years of observation. No consistent differences (within and between plants) were noted between observed and expected numbers concerning individual causes of death or individual cancer sites, apart from lung cancer. For this cause a tendency was observed for the standardised mortality ratio (SMR) to increase with time from first employment. When the data from all the plants were pooled a statistically significant raised SMR of 192 (17 observed, 8.9 expected; 95% confidence interval 117-307) appeared in the group with 30 years or more since first employment. The relevance of this finding, to which different factors including uncontrolled confounders such as smoking habits may have contributed, cannot be established at present. The result is suggestive, however, of an increased risk associated with the man made mineral fibres working environment of 30 or more years ago.

Europe↗
PubMed1984

A mortality study of workers employed in a German rock wool factory.

As part of a coordinated European study including 13 plants, 2,096 workers employed in rock wool production, packing, and maintenance activities in a German factory were followed until 1979 for cause-specific mortality. There were no consistent differences between the observed and expected deaths in the study cohort on the basis of the experience of the general population. The separate analysis of persons engaged in rock wool production and packing and those engaged in maintenance yielded an excess of lung cancer deaths with borderline significance for occurrence among the maintenance workers and an elevation in standardized mortality ratio for stomach cancer related to time since first employment in the production group. Comparison with a factory-based reference cohort did not show any increased health risk for the exposed cohort. An extension of the follow-up for five years is planned in an attempt to clarify the present findings.

Construction Materials↗