Search PubMed⌕ Search

Biomedical subjects

J Esteve

Publications and source records attributed to J Esteve.

At least 91 records · Page 5Linked to original sources
PubMed1991

Studies in gastric carcinogenesis. V. The effects of ascorbic acid on N-nitroso compound formation in human gastric juice in vivo and in vitro.

The concentrations of nitrite, thermo- and acetic acid-labile TEA-responsive compounds (TACs) and N-nitroso compounds (NOCs) as a group were measured in human gastric juice collected just before and 1, 2 and 4 h after oral ingestion of 1 g ascorbic acid (AA) or 200 mg sodium nitrate, separately or in combination. Individual responses of gastric [nitrite] following ingestion of AA alone varied widely, with both decreases and increases being observed, and showed no correlation with gastric pH. While a mixed response was also noted for [NOC] and [TAC], substantial decreases were observed in 5/6 individuals with initial [NOC] greater than 0.2 microM and 3/3 individuals with initial [TAC] greater than 0.2 microM, implying that (i) AA effectively inhibited gastric nitrosation and (ii) a basal amount of NOCs and TACs was present in gastric juice which could not be lowered by AA ingestion. Statistical analysis indicated that global mean values of gastric [NOC] were significantly reduced (P less than 0.02) 1-4 h after ingestion of AA. Ingestion of 200 mg sodium nitrate alone resulted in increases in gastric [NOC], which in some cases were very substantial. While nitrosation appeared lower following ingestion of the same dose of nitrate in combination with 1 g AA, the difference from the effects of nitrate alone was not statistically significant. In aqueous buffer, pH 2.5, and in the presence of 1 mM AA, 50 microM nitrite was consumed with a t1/2 of 50 min only if molecular oxygen had first been removed from the system. In the presence of oxygen, no consumption of nitrite could be detected in 50 min, reflecting nitrite recycling (oxidation of nitric oxide to higher oxides of nitrogen and hydrolysis back to nitrite). It is likely that nitrite recycling occurring after collection of gastric juice accounted for the inconsistent responses of gastric nitrite following ingestion of AA. Incubation of human gastric juice, pH 2.5, in vitro in the presence of 50 microM sodium nitrite for 60 min resulted in an increase of [NOC] and [TAC] from 0.10 to 0.70 and 1.10 microM respectively. Nitrosation was efficiently inhibited by AA, 2.27 mM AA resulting in 87 and 100% inhibition respectively. Removal of oxygen from the reaction mixture did not have any significant effect on the extent of nitrosation in the presence or absence of AA.

Ascorbic Acid↗
PubMed1989

Exposure to Legionellaceae at a hot spring spa: a prospective clinical and serological study.

Following the occurrence of five cases of Legionnaires' disease among patients and therapists at a French hot spring spa, a series of cleansing procedures and an epidemiological study were undertaken. During a 3-month period, the spring water was repeatedly sampled. Serum samples were taken from 689 randomly selected patients, 230 therapists, 134 administrative staff and a control group of 904 blood donors. Legionellaceae were present in the spring water at concentrations of 10(3)-10(5) colony forming units/l. Fifteen different species or serogroups were isolated with Legionella pneumophila serogroups 3 and 1 predominating. No clinical cases of Legionnaires disease were observed during the study. However, 11% of the therapists and 5% of the patients either had a high titre of antibody (greater than or equal to 256) to at least one species or serogroup or seroconverted during the study. Mean antibody titres in the three study groups were significantly higher than those in the blood donors against 11 of the 32 legionella antigens tested. Nine of these 11 antigens corresponded to species or serogroups isolated from the spring water. The highest mean antibody titres in all three study groups were against L. pneumophila serogroup 3, the most common legionella in the spring water. These findings have important implications for the maintenance of adequate standards of hygiene, bacteriological sampling and clinical surveillance in this and similar establishments.

Adult↗
PubMed1989

A comparison of two diet history questionnaires that measure usual food intake.

This study was conducted during the preparation of a case-control study on patients with adenomatous polyps or cancer of the large bowel. It was done to compare two dietary history methods for assessing individual current dietary intakes. Subjects were interviewed concerning their food consumption by meal in one of the questionnaires and by broad food groups in the other questionnaire. Two groups of 20 volunteers, comparable according to sex and age, were interviewed by a dietitian who used one of the questionnaires. Data on diets obtained with the questionnaire were compared with those of a 14-day dietary record. The subjects were informed of the importance of the validation procedure. Whatever the type of questionnaire, mean daily intakes of nutrients and foods were rather similar for the questionnaires and for the 14-day records. Thus, there were more significant correlations between the questionnaire by meal and the record than between the questionnaire by food group and the record. When using tertiles, it appears that the questionnaire by meal was better at classifying individuals with regard to their food intake than the questionnaire by food groups. Although extrapolating these results to a patient population is not straightforward, it seemed likely that interviewing patients on diet without using a pattern of meals would prove even less reliable than for healthy subjects. The questionnaire by meal was preferred to the questionnaire by food groups for the ongoing case-control study. Further studies are needed to know whether these results could be extrapolated to studies on past diet and to non-Latin populations.

Adult↗
PubMed1989

Reproductive and sexual risk factors and human papilloma virus infection in cervical cancer among Hong Kong Chinese.

In this case-control study of cervical neoplasia in Hong Kong, 48 dysplasia and 68 cancer patients were matched with 116 surgical in-patient controls. The cases had an earlier age at first intercourse and more sex partners than the controls. The cases' husbands also had more sex partners and were less likely to use condoms regularly. In a multiple regression model the odds ratio were 6.0 (95% Confidence Interval 2.5-14.6) for the husband having more than one sex partner, 4.0 (1.5-10.7) for the woman having more than one sex partner, and 1.15 (1.05-1.28) per year younger for the woman's age at first intercourse. The odds ratio of 5.4 for women whose partners did not habitually use condoms was not significantly different from 1.0. In a sub-sample, 37% of cancer patients and 18% of dysplasia patients, but only 6% of gynaecological controls, showed a positive DNA hybridization to Human Papilloma Virus (Type 16). These findings suggest that cervical cancer and dysplasia are sexually transmitted in our population, with a possible viral aetiology.

Adult↗
PubMed1989

Cervical screening attendance and its effectiveness in a rural population in China.

The results of a cervical cancer screening program in a population of 22,106 women aged over 25 years in a rural county of China are evaluated in a case-control analysis. The relative risk of cervix cancer was 0.33 in women with three or more negative tests (compared with one or less) and 11.4 for women whose last negative smear was 8 or more years previously (compared with 2 years or less). Attendance at the screening program was positively associated with some risk factors for cervix cancer (sexual behavior of the woman and her partner) and negatively associated with others (genital hygiene). Controlling for the confounding effect of these risk factors resulted in only small changes in the estimate of the protective effect of screening.

Adult↗
PubMed1988

Effects of timing and type of tobacco in cigarette-induced bladder cancer.

We analyzed a case-control study of bladder cancer in Torino (512 male and 55 female cases; 596 male and 202 female controls) with emphasis on the timing of cigarette smoking and the use of black or blond tobacco. The risk of bladder cancer was 2 to 3 times higher among smokers of black tobacco than among smokers of blond tobacco. Both groups of smokers showed a beneficial effect of smoking cessation, with an immediate decline in risk. This pattern is consistent with a late-stage effect of smoking. Among smokers of black tobacco, there was a gradient of risk with early exposure, and smokers who had quit never showed a drop to base-line levels of risk. These patterns, not apparent in users of blond tobacco, suggest an early stage effect of black tobacco, perhaps due to the higher concentration of aromatic amines in black than blond tobacco smoke and the higher blood levels of the hemoglobin adduct with 4-aminobiphenyl (a human bladder carcinogen) among smokers of black tobacco.

Age Factors↗
PubMed1988

Pharmacological profile of droxicam.

In Studies of anti-inflammatory activity, droxicam has shown itself to be as active as piroxicam and much more active than phenylbutazone, isoxicam and suprofen, both in acute studies such as carrageenin oedema, nystatin oedema and ultraviolet erythema, and in longer-term tests such as that of the cotton pellet. In the studies of anti-arthritic activity, which require long-term treatment, droxicam was as effective as piroxicam, both on primary and on secondary lesions. The study of analgaesic activity, conducted by means of the tests of protective activity against writhing induced by phenylbenzoquinone and acetylcholine bromide in the mouse and by acetic acid in the rat, droxicam activity was superior to that of acetylsalicylic acid, dipyrone, isoxicam and phenylbutazone. Droxicam also showed antipyretic activity in the rat, greater than that of acetylsalicylic acid, dipyrone and 4-aminoantipyrine, in the brewer's yeast and Salmonella typhi tests. Droxicam also acts as an ex vivo platelet aggregation inhibitor in the dog. In the study of inhibition of peritoneal capillary permeability in the mouse, droxicam was considerably more potent than isoxicam or phenylbutazone. Studies of general pharmacology have demonstrated that droxicam, at high doses, has no cardiovascular or respiratory effects, and that neither does it modify behaviour in rats and mice, determined by the Irwin test. Gastrointestinal tolerance of droxicam has been compared with that of piroxicam, and it has been found that droxicam is far better tolerated. The study of induction of gastrointestinal lesions in the rat demonstrated that the gastrolesive potential of droxicam is 10 times inferior to that of piroxicam.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Effects of droxicam on in vivo prostaglandin synthesis and ex vivo platelet aggregation.

Droxicam, similar to piroxicam, inhibits in vivo renal synthesis of PGF2 alpha. This study was performed in rats; droxicam and piroxicam were administered orally at doses of 0.5, 1.2 and 8 mg/kg. Inhibitory activity of the two compounds was similar (40-60%) but showed no dose-effect relationship. Maximum inhibition was obtained with the 1 mg/kg dosage. In dogs droxicam has shown a clear inhibitory effect on arachidonic acid induced ex vivo platelet aggregation. Droxicam was administered orally at a dose of 2 mg/kg. Maximum inhibition (-40%) was achieved 24 hr post-administration and the effect was sustained up to 72 hr (-23%).

Animals↗
PubMed1987

Acute, subacute and subchronic toxicity of besulpamide.

The acute oral and intraperitoneal toxicity of besulpamide has been studied in the rat and mouse, together with the subacute and subchronic oral toxicity in the rat at doses of 0, 125, 500 and 2000 mg/kg/day. The LD50 is in excess of 12,800 mg/kg by the oral route and in excess of 5,000 mg/kg intraperitoneally. Toxic signs were very slight and autopsy did not reveal lesions which could be attributed to the test substance. In the subacute and subchronic toxicities the characteristic effects of the diuretic activity were observed. In the subchronic toxicity study significant, although not dose-related, increases were observed in calcium, alkaline phosphatase, GPT and GOT levels. A decrease in liver-weight of the female animals with respect to controls was also noted. Histopathological studies did not reveal any changes which could be attributed to administration of the test substance. Besulpamide has demonstrated the typical effects of diuretics which are derivatives of 3-sulfamoyl-4-chlorobenzoic acid and in acute, subacute and subchronic tests by the oral route in the rat it has shown itself to be a substance of very low toxicity.

Administration, Oral↗
PubMed1987

Pharmacokinetics of besulpamide in rats and dogs.

The pharmacokinetics of besulpamide were studied in rats and its urinary excretion in rats and dogs. Kinetic characteristics were the same for both male and female rats according to a two-compartment open model. Biological half-life was 1-4 hr, absorption half-life was approximately 10 min and absolute bioavailability was nearly complete (F = 86.4%). In rats, urinary excretion of unchanged besulpamide was 30% after i.v. administration and 7% after oral administration, whereas in dogs after oral administration it was 54%. Values of the area under the plasma concentration-time curve in rats and percent of urinary excretion in dogs show that the kinetics of besulpamide are not dose-related when the drug is administered at doses of 10-50 mg/kg.

Animals↗
PubMed1987

Comparative light and electron microscopic observations of the lesive effects of two non-steroid anti-inflammatory drugs plus stress on rat gastric mucosa.

In this histological study it has been demonstrated that a single-dose administration of piroxicam, at the same dosage (4 mg/kg) as droxicam, has a greater erosive potential on the gastric mucosa of rats later exposed to cold stress. For this purpose the depth of all lesions found was evaluated by light microscopy and results showed that piroxicam produces lesions deeper and more numerous than those of droxicam. The transmission and scanning electron microscopic studies showed that the lesive mechanism was very similar for both drugs and that both local and general factors induced by these drugs and stress come into play. Absorption or penetration and uptake by the cells of the mucosa have been considered among the most important local factors in the development of erosive gastric lesions caused by non-steroid anti-inflammtaory drugs. As this absorption is in direct relation to the depth of the lesions, it can be considered from the results of this study that the lesser lesive effect of droxicam on the gastric mucosa when compared to that of piroxicam is due to the fact that, owing to its hydrolysis to piroxicam the absorption rate is slower.

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

Mortality experience in a polyamide-polyester factory.

Chemical workers have become increasingly concerned about the presence of carcinogens in their occupational environment. As a result, a number of studies of excess cancer mortality have been undertaken in groups of workers with well-characterized exposures. This paper reports the results of one such study carried out in a polyamide-polyester factory in France. A retrospective cohort design was chosen to evaluate the effect of exposure to phthalates, nickel catalyzers, and other chemicals in the work environment. Only a slight excess of cancers, marginally related to exposure category yet not significantly related to length of exposure, was found. The cohort, however, was young but stable, and a continued follow-up is therefore both feasible and justifiable, since it is likely to yield important information about the potential hazards associated with the tergal polymer industry.

Chemical Industry↗
PubMed1985

A collaborative study of a preparation of normal human serum for use as a reference in the assay of beta 2 microglobulin.

A biological standard for beta 2 microglobulin (beta 2m) determination has been prepared from pooled human serum by sampling and freeze-drying. A preliminary study of parallelism between the dose-response curves of the preparation and pure beta 2m or biological fluids was made with four different methods of assay and gave satisfactory results. In a collaborative study in five laboratories in five countries using a common method of assay, evidence was obtained that the preparation coded 80-12-3200 was suitable to serve as a standard for the assay of beta 2 microglobulin. Criteria included the constancy of the amount of material per vial and the stability of the freeze-dried product. The technique used for beta 2m determination was a radioimmunoassay.

Drug Stability↗
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↗
PubMed1983

Pipe, commercial and hand-rolled cigarette smoking in oesophageal cancer.

The relative risks of oesophageal cancer involved in the smoking of pipe, commercial and hand-rolled cigarettes were examined after adjustment for age, alcohol and total tobacco consumption. In contrast with what has been observed for lung and laryngeal cancer, pipe and hand-rolled cigarettes entail a risk of oesophageal cancer that is not inferior and probably greater than commercial cigarette smoking. This indicates that the mode of action of tobacco on the oesophagus may be related to the swallowing of smoke condensates.

Aged↗