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Biomedical subjects

L Raymond

Publications and source records attributed to L Raymond.

At least 73 records · Page 4Linked to original sources
PubMed1988

[Swiss interregional epidemiologic study of the risk of cancer in the contralateral breast].

This epidemiologic investigation in three Swiss regions (Geneva, St. Gall-Appenzell, Vaud) included 5,193 women diagnosed as having a first primary breast cancer. The patients were followed up for ten years (the observation totalled 24,994 women-years). Overall, these results confirmed that the relative risk of a second breast cancer was greatly increased during the first year following the primary diagnosis, but this was largely due to simultaneously discovered contralateral tumours. Beyond the first year of follow-up, the relative risk of a second tumour was lower but still significantly greater than unity. No significant diminution of the excess risk was observed in the first 10 years of follow-up. Relative risk of a second breast cancer was generally higher before age 50, independently of the latency. The relative risk of a second breast cancer differed significantly from one region to another, possibly due to specific techniques of registration.

Adult↗
PubMed1987

[Nutritional profile of patients with cancer of the pancreas].

A case control study was carried out in the Geneva area from 1976 to 1980 to determine correlation between cancer of the pancreas and nutrition. The controls were randomly selected from the general population and 88 patients with pancreatic cancer were interviewed on their food habits by two experienced dietitians. Bias may always be suggested, but even Anglo-Saxon workers are increasingly adopting this method. Comparison between patients with pancreatic cancer and controls revealed different alimentary habits. Consumption of beer (2.9 times higher risk), of butter (2.1 times) and pasta (2.5 times) considerably increases the risk, whereas margarine, fruit and fresh vegetables are associated with a significant reduction of risk.

Beer↗
PubMed1987

[A plan for a randomized evaluation study for improving the memory of the aged].

The training is realised through exercises carried out during courses and at home. The effectiveness of this training is assessed by psychometric tests (before/after) and a questionnaire for self evaluation (after). An equal number of subjects to be trained and controls are selected among 100 or so voluntary participants.

Aged↗
PubMed1987

[Assessment of the nutritional intake of the adult population of Geneva based on individual quantitative questionnaires].

This paper presents the variation in dietary intake, according to sex and age, observed among a representative sample of the over-19-years old residents of Canton Geneva (Switzerland). 576 men and 384 women have been interviewed by 2 specially trained dietitians using a dietary history questionnaire (7.9% of the total population). Differences between sexes are essentially a matter of quantities: in grams or kilocalories, men eat more of all nutriments than women. The energetic intake of the males exceeds by 600 kcal the one of the females. This difference is partly due to a mean alcoholic intake of 44 g for the men and 13.7 g for the women. But the percent of each nutriment in the energetic intake, without alcohol, is the same in both sexes, i.e. 15 +/- 2% of proteins, 40 +/- 6% of lipids and 45 +/- 7% of glucids. The same phenomenon can be seen in Oriental Flandras, in Liège or in Calvados. Age is an important factor influencing all types of nutrient intakes. Our data show that when men or women get older, the percentage of lipids and protids in the energetic intake tends to decrease while the percentage of glucids increases. The total lipid intake decreases with age but the polyunsaturated/saturated fatty acid ration remains constant with age. This observation could be associated with a change in dietary habits of the elderly, a difference of diet from one generation to the other, or the result of a mortality excess among individuals that had an hyperlipidic diet.

Adult↗
PubMed1986

C-ras expression decreases during in vitro senescence in human fibroblasts.

Expression of the c-ras oncogene was determined in growing early and late passage human (IMR-90) fibroblasts using northern blot analysis of total cellular RNA. It was found that late passage cells demonstrated lower levels of c-ras by about four fold when compared to levels found in early passage cells. Southern blot analysis of genomic DNA from early and late passage fibroblasts digested with either SacI or BamHI showed somewhat increased hybridization levels in early passage cells compared to late passage cells. Data is discussed in relation to a previous report of c-ras expression and gene amplification.

Cell Cycle↗
PubMed1986

Gating of a voltage-dependent channel (colicin E1) in planar lipid bilayers: the role of protein translocation.

The voltage-dependent channel formed in planar lipid bilayers by colicin E1, or its channel-forming C-terminal fragments, is susceptible to destruction by the nonspecific protease pepsin under well-defined conditions. In particular, pepsin acts only from the cis side (the side to which colicin has been added) and only upon channels in the closed state. Channels in the open state are refractory to destruction by cis pepsin, and neither open nor closed channels are destroyed by trans pepsin. Colicin E1 channels are normally turned on by cis positive voltages and turned off by cis negative voltages. For large (greater than 80 mV) positive voltages, however, channels inactivate subsequent to opening. Associated with the inactivated state, some channels become capable of being turned on by cis negative voltages and turned off by cis positive voltages, as if the channel-forming region of the molecule has been translocated across the membrane. Consistent with this interpretation is the ability now of trans pepsin to destroy these "reversed" channels when they are closed, but not when they are open, whereas cis pepsin has no effect on them in either the open or closed state. Our results indicate that voltage gating of the E1 channel involves translocation of parts of the protein across the membrane, exposing different domains to the cis and trans solutions in the different channel states.

Alkanes↗
PubMed1986

Gating of a voltage-dependent channel (colicin E1) in planar lipid bilayers: translocation of regions outside the channel-forming domain.

C-terminal fragments of colicin E1, ranging in mol wt from 14.5 to 20 kD, form channels with voltage dependence and ion selectivity qualitatively similar to those of whole E1, placing an upper limit on the channel-forming domain. Under certain conditions, however, the gating kinetics and ion selectivity of channels formed by these different E1 peptides can be distinguished. The differences in channel behavior appear to be correlated with peptide length. Enzymatic digestion with trypsin of membrane-bound E1 peptides converts channel behavior of longer peptides to that characteristic of channels formed by shorter fragments. Apparently trypsin removes segments of protein N-terminal to the channel-forming region, since gating behavior of the shortest fragment is little affected by the enzyme. The success of this conversion depends on the side of the membrane to which trypsin is added and on the state, open or closed, of the channel. Trypsin modifies only closed channels from the cis side (the side to which protein has been added) and only open channels from the trans side. These results suggest that regions outside the channel-forming domain affect ion selectivity and gating, and they also provide evidence that large protein segments outside the channel-forming domain are translocated across the membrane with channel gating.

Colicins↗
PubMed1986

[The contribution of alcohol to nutrition: addition or substitution according to cultural origins].

The relation of alcohol intake to diet is analyzed through multiple linear regression for a sample of 475 males living in Geneva. Control variables are age, relative weight index, marital status and employment status. Whereas alcohol is associated with higher dietary intake for people of mediterranean origin, it tends to replace food calories for natives of german speaking areas.

Age Factors↗
PubMed1986

[Colorectal polyps and cancers by sub-site: epidemiologic findings in Geneva and Vaud].

The present study is a comparative analysis of the adenomatous polyps and colorectal cancers, registered during a determined period within the population of the cantons of Geneva and Vaud. The analysis is particularly based on the polyp/cancer ratio by sub-site. Histological type as well as age and sex of the patient are taken into consideration.

Adult↗
PubMed1985

[Interaction of alcohol and nutrition factors in the etiology of hepatic cirrhosis in men].

Habitual food and alcohol intake throughout adult life were assessed by interview in 211 patients suffering of liver cirrhosis and 387 control subjects selected at random from the corresponding general population. In the cirrhotics only the habits prior to clinical disease were taken into account. A significant dose-response relationship between alcohol intake and relative risk of cirrhosis, as well as the protective effect of total caloric intake and of its protein fraction, was demonstrated by logistic regression analysis.

Adult↗
PubMed1985

Channels formed by colicin E1 in planar lipid bilayers are large and exhibit pH-dependent ion selectivity.

The E1 subgroup (E1, A, Ib, etc.) of antibacterial toxins called colicins are known to form voltage-dependent channels in planar lipid bilayers. The genes for colicins E1, A and Ib have been cloned and sequenced, making these channels interesting models for the widespread phenomenon of voltage dependence in cellular channels. In this paper we investigate ion selectivity and channel size--properties relevant to model building. Our major finding is that the colicin E1 channel is large, having a diameter of at least 8 A at its narrowest point. We established this from measurements of reversal potentials for gradients formed by salts of large cations or large anions. In so doing, we exploited the fact that the colicin channel is permeable to both cations and anions, and its relative selectivity to them is a function of pH. The channel is anion selective (Cl- over K+) in neutral membranes, and the degree of selectivity is highly dependent on pH. In negatively charged membranes, it becomes cation selective at pH's higher than about 5. Experiments with pH gradients cross the membrane suggest that titratable groups both within the channel lumen and near the channel ends affect the selectivity. Individual E1 channels have more than one open conductance state, all displaying comparable ion selectivity. Colicins A and Ib also exhibit pH-dependent ion selectivity, and appear to have even larger lumens than E1.

Colicins↗
PubMed1985

[Individual and familial characteristics in the etiology of cancer: epidemiologic approach].

The present report discusses the main constraints influencing the choice in the method in the epidemiological approach of host factors and family factors. It briefly describes 3 of the usual methods in this field, i.e. the migrant studies, the twin studies and the family studies. The practical problems and the conceptual limitations met by each of these 3 methods are reviewed. A brief review of the literature provides an opportunity for examining the main misunderstandings between geneticists and epidemiologists in their study of human groups when analysing the role of such factors in the etiology of cancer.

Diseases in Twins↗
PubMed1985

Increased risk for male bladder cancer among a cohort of male and female hairdressers from Geneva.

A cohort of 703 male and 677 female hairdressers born from 1880 onwards, who started to run salons in Geneva between 1900 and 1964 was followed-up to the end of 1982. Cause-specific mortality was analysed from 1942 to 1982 and a significant excess mortality from bladder cancer (observed deaths = 10, expected deaths = 3.9) was found among males. Cancer incidence recorded for the years 1970 to 1980 showed a significant increase among males for all neoplasms (O = 65, E = 51.4), cancer of the buccal cavity and pharynx (O = 6, E = 2.5), cancer of the prostate (O = 12, E = 6.1), and bladder cancer (O = 11, E = 5.3). Among female hairdressers no significant increase in mortality or in cancer incidence was found. Mean age at diagnosis of the 18 deaths and/or incident cases from bladder cancer found among the male hairdressers was 68.6 years (range 51-88) and mean latency period since first exposure was 52.2 years (range 24-73). Occupational history was obtained for most of the 18 cases and of 54 controls randomly selected from the cohort. Little evidence was found of a causal relationship between exposure to hair dyes and the excess risk for bladder cancer among the male hairdressers. It is a suggestion that this excess might be related to some colouring agent(s) in brilliantines which were widely used in men's hairdressing salons in Geneva until about 1950.

Adult↗
PubMed1985

Mortality and cancer incidence in the perfumery and flavour industry of Geneva.

An analysis has been made of the mortality and cancer incidence of 1168 workers who entered the three factories of the perfumery industry of the Canton of Geneva from their establishment at the turn of the century to the end of 1964. The workers were followed up from their entry until 31 December 1980, at which date 344 were dead and 28 lost to follow up. Among the whole study population only mortality from tuberculosis was significantly raised; there was no significant increase in the incidence of or mortality from any cancer. Analysis by four exposure categories showed a significant excess of deaths from heart disease among the compounders. In addition, two deaths from aplastic anaemia were recorded in chemical process workers exposed to benzene. Further analysis by cohort of entry and by birth cohort indicated that, among the subgroup of men first employed in 1900-29 and born in 1880-99, the mortality from a wide range of causes was significantly increased below the age of 70. This increase is unlikely to be due to an occupational factor as indicated by the absence of an upward trend of mortality with longer exposure.

Aged↗