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Biomedical subjects

J P Arnould

Publications and source records attributed to J P Arnould.

16 recordsLinked to original sources
PubMed2002

Variation in plasma leptin levels in response to fasting in Antarctic fur seals (Arctocephalus gazella).

Plasma leptin levels were determined in 8 lactating female and 20 pup Antarctic fur seals (Arctocephalus gazella) during fasting periods of normal duration. Plasma leptin levels ranged from 1.35 3.19 ng x ml(-1) in lactating females and 1.79-4.80 ng x ml(-1) in pups and were not positively correlated with body mass or condition. A negative trend, however, was observed between plasma leptin levels and body condition in lactating females upon their arrival at the colony following a foraging trip (beginning of fast). In accordance with findings in other species, plasma leptin levels dropped significantly (P < 0.02) in response to the 17-19% drop in body mass experienced by pups during fasting. In contrast, plasma leptin levels in lactating females increased during the first 24 h of fasting before decreasing throughout the remaining 48 h of the fast. This unexpected result could be due to the high level of energy expenditure by seals as they swim back to the colony (i.e. post-exercise response) or may be influenced by the intense suckling activity experienced by females during the onshore fasting periods. The results of this study support recent findings in other carnivore species which suggest the primary physiological role of leptin in these species may not necessarily be as a signal of the magnitude of body energy reserves.

Animals↗
PubMed2001

Fasting metabolism in Antarctic fur seal (Arctocephalus gazella) pups.

The metabolism of 52-73-day old Antarctic fur seal pups from Bird Island, South Georgia, was investigated during fasting periods of normal duration while their mothers were at sea foraging. Body mass decreased exponentially with pups losing 3.5-3.8% of body mass per day. Resting metabolic rate also decreased exponentially from 172-197 ml (O2) x min(-1) at the beginning of the fast and scaled to M(b)(0.74) at 2.3 times the level predicted for adult terrestrial mammals of similar size. While there was no significant sex difference in RMR, female pups had significantly higher (F(1,18)=6.614, P<0.019) mass-specific RMR than male pups throughout the fasting period. Fasting FMR was also significantly (t(15)=2.37, P<0.035) greater in females (823 kJ x kg(-1) x d(-1)) than males (686 kJ x kg(-1) x d(-1)). Average protein turnover during the study period was 19.3 g x d(-1) and contributed to 5.4% of total energy expenditure, indicating the adoption of a protein-sparing strategy with a reliance on primarily lipid catabolism for metabolic energy. This is supported by observed decreases in plasma BUN, U/C, glucose and triglyceride concentrations, and an increase in beta-HBA concentration, indicating that Antarctic fur seals pups adopt this strategy within 2-3 days of fasting. Mean RQ also decreased from 0.77 to 0.72 within 3 days of fasting, further supporting a rapid commencement of protein-sparing. However, RQ gradually increased thereafter to 0.77, suggesting a resumption of protein catabolism which was not substantiated by changes in plasma metabolites. Female pups had higher TBL (%) than males for any given mass, which is consistent with previous findings in this and other fur seal species, and suggests sex differences in metabolic fuel use. The observed changes in plasma metabolites and protein turnover, however, do not support this.

3-Hydroxybutyric Acid↗
PubMed2001

Chemical characterisation of the oligosaccharides in hooded seal (Cystophora cristata) and Australian fur seal (Arctocephalus pusillus doriferus) milk.

Carbohydrates were extracted from hooded seal milk, Crystophora cristata (family Phocidae). Free oligosaccharides were separated by gel filtration and then purified by ion exchange chromatography, gel filtration and preparative thin layer or paper chromatography and their structures determined by 1H-NMR. The hooded seal milk was found to contain inositol and at least nine oligosaccharides, most of which had lacto-N-neotetraose or lacto-N-neohexaose as core units, similar to those in milk of other species of Carnivora such as bears (Ursidae). Their structures were as follows: Gal(beta1-4)Glc (lactose); Fuc(alpha1-2)Gal(beta1-4)Glc (2'-fucosyllactose); Gal(beta1-4)GlcNAc(beta1-3)Gal(beta1-4)Glc (lacto-N-neotetraose); Fuc(alpha1-2)Gal(beta1-4)GlcNAc(beta1-3)Gal(beta1-4)Glc (lacto-N-fucopentaose IV); Gal(beta1-4)GlcNAc(beta1-3)[Gal(beta1-4)GlcNAc(beta1-6)]Gal(1-4)Glc (lacto-N-neohexaose); Fuc(alpha1-2)Gal(beta1-4)GlcNAc(beta1-3)[Gal(beta1-4)GlcNAc(beta1-6)]Gal(beta1-4)Glc (monofucosyl lacto-N-neohexaose a); Gal(beta1-4)GlcNAc(beta1-3)[Fuc(alpha1-2)Gal(beta1-4)GlcNAc(beta1-6)]Gal(beta1-4)Glc (monofucosyl lacto-N-neohexaose b); Fuc(alpha1-2)Gal(beta1-4)GlcNAc(beta1-3)[Fuc(alpha1-2)Gal(beta1-4)GlcNAc(beta1-6)]Gal(beta1-4)Glc (difucosyl lacto-N-neohexaose); Gal(beta1-4)GlcNAc(beta1-3)Gal(beta1-4)GlcNAc(beta1-3)Gal(beta1-4)Glc (para lacto-N-neohexaose); Fuc(alpha1-2)Gal(beta1-4)GlcNAc(beta1-3)Gal(beta1-4)GlcNAc(beta1-3)Gal(beta1-4)Glc (monofucosyl para lacto-N-neohexaose). Milk of the Australian fur seal, Arctophalus pusillus doriferus (family Otariidae) contained inositol but no lactose or free oligosaccharides. These results, therefore, support the hypothesis that the milk of otariids, unlike that of phocids, contains no free reducing saccharides.

Animals↗
PubMed2000

Detection of benzo[a]pyrene-DNA adducts in leukocytes of coke oven workers.

Coke oven workers are often heavily exposed to polynuclear aromatic hydrocarbons (PAHs) and particularly to benzo[a]pyrene (B[a]P), which has been associated with a high incidence of cancer. B[a]P is metabolically activated to its diol-epoxide derivative, benzo[a]pyrene-trans-7,8-dihydrodiol-9,10-epoxide (BPDE-I), a potent carcinogen which binds covalently to DNA, thereby producing BPDE-I-DNA adducts. In this study, an investigation was made of the exposure of coke oven workers to PAH via the measurement of urinary 1-hydroxypyrene (1-OHP) levels, and of exposure to B[a]P by the analysis of BPDE-I-DNA adducts in leukocytes using an ELISA competitive immunoassay. 1-OHP levels measured in post-shift samples correlated with those of DNA adducts detected in leukocytes, with a mean value (140.11 fM/50 micrograms of DNA) which differed significantly from the control value (P < 0.001). It is concluded that measurement of BPDE-I-DNA adduct levels in coke plant workers is essential in determining cancer risk due to high exposure to PAHs, and in particular of B[a]P.

Air Pollutants, Occupational↗
PubMed1999

Biological monitoring exposure of workers from plant producing carbon electrodes: quantification of benzo[a]pyrene DNA-adducts in leukocytes, by a 32P-postlabelling method and an immunoassay.

The levels of benzo[a]pyrene were monitored for blood DNA-benzo[a]pyrene adducts in 17 workers from a plant producing carbon electrodes, with high exposure to benzo[a]pyrene (575-902-1149 ng m(-3)). Two different techniques, a 32P-postlabelling method and a competitive immunoassay using polyclonal antibodies obtained from rabbits immunised with DNA modified by benzo[a]pyrene-trans-7,8-dihydrodiol-9,10-epoxide were used. For each worker, urinary 1-hydroxypyrene, a potential indicator of exposure to polycyclic aromatic hydrocarbons, was measured. The effect of tobacco by urinary cotinine measurement was also considered. The postlabelling and immunoassay detection limits for DNA-benzo[a]pyrene adducts were respectively 0.15 and 10 fmol 50 microg(-1) of DNA. The results obtained by the two methods demonstrated a good detection of DNA-benzo[a]pyrene adducts, but no direct relationship between the quantity of adducts and the concentration of benzo[a]pyrene in air-borne was noted in the studied plant. The levels of DNA-benzo[a]pyrene adducts obtained by immunoassay were significantly higher than those obtained by the 32P-postlabelling (P < 0.001). For several workers, variations due to professional or non professional factors must be taken into account in interpreting the results. In conclusion, the two methods used proved very efficient in determining DNA-benzo[a]pyrene adducts, and may be useful in monitoring human exposure to known and previously unidentified environmental genotoxic agents.

Adult↗
PubMed1998

Detection of benzo[a]pyrene-DNA adducts from leukocytes from heavy smokers.

Benzo[a]pyrene is a cigarette smoke component that is metabolized in the human body to the diol-epoxide derivative benzo[a]pyrene-trans- 7,8-dihydrodiol-9,10-epoxide (BPDE-I), which is the final carcinogen. BPDE-I binds covalently to DNA, producing BPDE-I-DNA adducts. A competitive immunoenzymetric assay was used to measure BPDE-I-DNA adducts in blood samples from 58 heavy smokers, 32 men and 26 women, attending a smoking cessation clinic. Cigarette consumption was evaluated based on urinary continine levels. None of the subjects worked in jobs involving exposure to polycyclic aromatic hydrocarbons (e.g., benzo[a]pyrene). Concentrations of BPDE-I-DNA adducts varied with cigarette consumption, ranging from 10.00 to 28.20 fmol/50 micrograms of DNA.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed1997

Detection of benzo[a]pyrene-DNA adducts in human placenta and umbilical cord blood.

Placenta constitutes a vital organ of exchange between mother and foetus. In addition to this favourable effect for foetal development, placenta indirectly may allow transfer of several maternal blood xenobiotics. Human placenta and umbilical cord blood are interesting models for investigating maternal environment and the metabolism, the bioactivation and the transfer of carcinogens such as polycyclic aromatic hydrocarbons. We used them to assess the effect of a woman's smoking on the foetus. Few studies cover this subject. In pregnant women who have continued to smoke, benzo[a]pyrene compound of cigarette smoke is metabolically activated to diol-epoxide derivative: benzo[a]pyrene-trans-7,8-dihydrodiol-9,10-epoxide, ultimate carcinogen (BPDE-I). This derivative is covalently fixed on DNA and gives BPDE-I-DNA adducts. By a competitive immunoassay technique, we determined BDPE-I-DNA adducts in 20 samples of placenta and umbilical cord blood from women who smoked (n = 15) and who did not (n = 10). Tobacco consumption was checked by urinary cotinine determination. In the group of smokers levels of adducts were found in 13 specimens of placenta (from 10 to 60 fmol/50 micrograms of DNA) and 12 umbilical cord blood (from 10 to 22.15 fmol/50 micrograms of DNA) samples. These results indicate that a mother's tobacco consumption is linked to the accumulation of BPDE-I-DNA adducts in the placenta, which are seen in smaller quantities in the umbilical cord blood, probably because of the metabolic capacity of the placenta and the transfer of B[a]P from the mother to the foetus.

Adolescent↗
PubMed1984

A new viscoelastometer for studying the rheological properties of bronchial mucus in clinical practice.

In clinical practice, a wide variety of drugs are given to modify the rheological properties of bronchial mucus but they are frequently not correctly chosen because there is not a simple apparatus available for the routine measurement of the mucus viscoelasticity. We designed a new viscoelastometer which is easy to operate and permit accurate measurement of the viscoelastic properties of mucus. The system has a Couette geometry and requires a sample of 1 ml. The outer cylinder is thermostated and rotates at a constant rate. The resulting torque is measured on the inner cylinder using a microdisplacement transducer. The inner cylinder is suspended by a special wire system which maintains a constant 0.75 mm gap between the two cylinders. The apparent viscosity is calculated up to 100 Pa.s. at a low shear rate (0.4 s-1) and the elasticity is analyzed by a stress relaxation method. The characteristics of the apparatus and the typical viscoelasticity behaviour of several sputum samples are reported.

Bronchi↗
PubMed1984

A new apparatus for measuring the thread-forming property (spinability) of biological fluids.

Spinability is a rheological parameter which characterizes the property of fluids to be drawn into threads when stretched. It has been shown that this property is of particular importance in the mucus transport process. This paper describes an automatic apparatus which measures the spinability of a calibrated volume (20 microliters) of sample at a stretching rate of 10 mm.sec.-1. The reproducibility of the measurements is analyzed on mucus simulants and on different types of bronchial mucus. Using this technique, we observed that the spinability of bronchial secretions is significantly correlated (r = 0.69, p less than 0.001) with their transport rate measured on the depleted frog palate. This device is suitable for measuring the spinability of all conductive types of mucus and other biological fluids.

Body Fluids↗
PubMed1984

A technique for continuously measuring filtration resistance at constant pressure.

A device for continuously measuring, at constant pressure, the filtration resistance of different liquid suspensions is described. It is made up of two main parts: flowmeter system and electronic circuit. The flowmeter consists of a capillary tube and a sensitive pressure transducer, and has a time response of 100 ms and a linearity of +/- 1% from 1 uls-1. The electronic part allows the calculation and recording of flow versus time and filtration resistance versus the volume which passes through the filter. Principle, technical characteristics of the system and examples of recording with several Red Blood Cell populations are reported.

Electronics↗
PubMed1978

Primary malignant melanoma of the cerebellum: a case with metastases outside the nervous system.

A case of primary intracranial melanoma in a 65-year-old female is described. A complete postmortem examination revealed multiple metastases in the liver, and eliminated the possibility of an extraneural primary melanoma. A review of the literature confirmed that such cases are highly exceptional, and that an exhaustive autopsy including particularly the eyes is indispensable to substantiate the diagnosis. When these conditions are fulfilled, there is no reason not to consider the eventuality of visceral deposits from a primary melanoma of the central nervous system.

Aged↗
PubMedDate not supplied

The composition of Australian fur seal (Arctocephalus pusillus doriferus) milk throughout lactation.

The proximate chemical composition of milk was determined throughout lactation in the Australian fur seal (Arctocephalus pusillus doriferus Wood Jones), a temperate species with an 11-mo lactation period typical of most temperate otariids. Average lipid and protein contents were 42% and 10%, respectively, which is similar to that recorded for the polar otariid species but higher than reported in other temperate, long-lactation species. Milk composition, however, varied substantially throughout lactation, with lipid content rising from 30% soon after parturition to 50% at 230 d postpartum before decreasing to 45% toward weaning. The trend in water content was opposite to that of lipid, while protein content increased only slightly during lactation from 10% to 12%. The peak in lipid content occurred at approximately 70% of the way through lactation, similar to that found in the Australian sea lion and several phocid seal species. Significant positive relationships were found between milk lipid content and both the duration of the preceding foraging trip and body mass. A highly significant and close correlation was found between milk water and lipid contents such that gross energy content may be accurately predicted from water content alone. Similar predictive equations have been found for several other otariid and phocid species, but these appear to differ between phylogenetic groups.

Animals↗
PubMedDate not supplied

[A microprocessing system for respiratory epidemiological studies (author's transl)].

A microprocessing system designed to collect and analyse data from respiratory epidemiological studies is described. It has several independent modules. The first module presents the questions from the European Coal and Steel Community questionnaire in a logical sequence and analyses and stores the responses. The second module is associated with a device that measures CO diffusion and determines gas exchange; it calculates, displays and stores the results. The last module collects and integrates digitally the flow measured at the mouth by a pneumotachograph during forced expiration, then displays and calculates the principal indices when certain programmed criteria for selection of flow-volume curves are met. All modules are connected to a numerical magnetic tape-recorder which centralizes the information data. The system is easily transportable and satisfactory for epidemiological studies.

Carbon Monoxide↗