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Biomedical subjects

G Jourdan

Publications and source records attributed to G Jourdan.

17 recordsLinked to original sources
PubMed1998

Evidence for high genetic diversity and long-term endemicity of hepatitis C virus genotypes 1 and 2 in West Africa.

During 1994 and 1995, the prevalence of hepatitis C virus (HCV) and its genotypes were studied in several rural and urban populations in three West African countries: Guinea, Burkina Faso, and Benin. The following groups were screened for antibodies to HCV (anti-HCV): 459 villagers in the forest region of Guinea; 965 individuals in urban, suburban, and rural populations of the Bobo Dioulasso area, Burkina Faso; and 582 blood donors in Cotonou, Benin. In Benin, 60 patients with sickle cell anemia (30 with and 30 without history of multiple transfusion) and 13 hospital patients with liver disease were also tested. RT-PCR detection of HCV-RNA was carried out on all anti-HCV positive samples, followed by genotyping and sequencing of unrecognized subtypes. The prevalence rates of anti-HCV were 1.1% in the Guinean population group, 1.4% among blood donors in Benin, and 4.9% in residents of Burkina Faso. In patients with sickle cell anemia, five of the 30 polytranfused patients (17%) had anti-HCV, whereas none of the patients without a history of blood transfusion had anti-HCV (P < 0.05). Among the 13 patients with liver disease, five had anti-HCV, of whom four had history of blood transfusion. HCV-RNA was detected in 41 anti-HCV positive sera. All belonged to genotypes 1 or 2, with a high genomic diversity; 18 different subtypes were identified, including 2c, 2d, and 16 new subtypes. Such genetic diversity poses a challenge for vaccine development and also implies that HCV infection is long-established in these West African regions.

Adolescent↗
PubMed1995

Pharmacokinetic, metabolic, and antidiarrheal properties of (D and L) heptapeptides of sorbin in rodent.

The C-terminal heptapeptide-amide (C7-sorbin) is the minimal biologically active fragment of sorbin inducing an increase in intestinal hydroelectrolytic absorption. An analogue (D7-sorbin), characterized by the replacement of the ultimate C-terminal amino acid L-alanine-amide by D-alanine-amide, was synthetized. For pharmacokinetic studies, D7-sorbin and C7-sorbin were tritium labeled. After IV injection, clearances were 10.6 and 30.2 ml-1 for D7-sorbin and C7-sorbin, respectively, and MRT were 34 and 18 min. After SC administration, Cmax attained 0.41% and 0.12% of the dose/ml, respectively. The IP route showed a 45-min delay before Cmax and a 100% bioavailability for both peptides. D7-sorbin was principally excreted in urine, as shown by balance study, and in part in intact form, as controlled by mass spectrometry. D7-sorbin induced a significant decrease of the VIP-induced ileal secretion, previously observed with C7-sorbin. The change of L-Ala to D-Ala increased the stability of the synthetic C-terminal peptide of sorbin whereas its biological activity, bioavailability, and route of elimination were unchanged.

Animals↗
PubMed1994

Pharmacokinetics and organ distribution of the sorbin C-terminal peptides.

Sorbin is a 153 amino acid peptide isolated from porcine small intestine. The heptapeptide-amide is the minimal active site of the natural molecule. A comparison of the distribution of C-7 and C-20 sorbin, which have been shown to share the activity of sorbin in increasing intestinal absorption of electrolytes, was undertaken by radioimmunoassay, after perfusion of 200 micrograms/kg/h. A longer half-life in plasma was observed for C-20 sorbin than for C-7 sorbin, with a clearance rate of 18 +/- 4 ml/min/kg vs. 40.6 +/- 13.5 ml/min/kg and a distribution volume of 192 +/- 35 ml/kg vs. 286 +/- 123 ml/kg. The accumulation of tritiated C-7 sorbin was observed in enterocytes, serosal acini of the salivary glands, and fundus chief cells. The recovery of intact peptide in the intestine was 0.06% per gram of tissue. Eighteen percent of the peptide was detected in urine.

Amino Acid Sequence↗
PubMed1993

Interaction between pepsin and acid secretion during fundic perfusion in cat and rabbit.

1. The effect of perfusion at pH 5.5 of a Heidenhain pouch on acid and pepsin secretion was studied in cats and rabbits. 2. In basal conditions, acid secretion was not modified by the perfusion while pepsin secretion was increased in both species. 3. After a meal, the perfusion did not modify the stimulation of acid secretion in cats nor the absence of secretions in rabbit. Stimulation of pepsin secretion was the same with or without perfusion in both species. 4. In rabbit, in contrast to cat, pepsin and acid secretions were independent during the meal-induced phase of gastric secretion.

Animals↗
PubMed1992

Effect of sorbin on duodenal absorption of water and electrolytes in the rat.

Sorbin is a newly isolated intestinal peptide that has been purified because of its ability to induce water absorption. The effects that sorbin and some synthetic peptides corresponding to its C-terminal sequence have on duodenal absorption of water, chloride, and sodium were studied in comparison with the effects of vasoactive intestinal peptide (VIP), [D-Ala,Met]-enkephalinamide (DAMA), and angiotensin II. The technique of an in situ ligated duodenal loop in the rat was used for all peptides. Under the experimental conditions used, a low basal secretion of water, chloride, and sodium was obtained; VIP induced an increase of the secretion, whereas DAMA induced an absorption, both in the nanomolar dose range. Angiotensin II and sorbin induced an absorption in the picomolar dose range. The most effective doses of sorbin peptides but not of angiotensin induced the lowest final concentrations of Na+ and Cl- obtainable without inducing secondary water secretion. All synthetic peptides containing the C-terminal heptapeptide of sorbin were active in the picomolar dose range. Contrary to angiotensin, they had no effect on blood pressure.

Amino Acid Sequence↗
PubMed1991

Isolation and characterisation of porcine sorbin.

Sorbin has been isolated from extracts of porcine upper intestine, and the biological activity in absorbing water and electrolytes utilized to monitor the purification procedure. Pure sorbin was obtained in a yield of about 1 mg/Mg boiled intestine. The protein chain has 153 amino acid residues and the primary structure was determined by analyses of CNBr-cleaved fragments and four enzymatic digests. The protein has a free N-terminal Met and an amidated C-terminal Ala. No structural similarity was observed with other known proteins in data bases, but several segments have special properties and the C-terminal half is rich in Pro and Arg.

Absorption↗
PubMed1991

[Investigation of a transfusion contaminated by HTLV-I virus].

In front of the successive development of an HTLV-I seroconversion and a neuromyelopathy in a French Caucasian following a cardiac transplantation, an ascendant epidemiologic investigation must be manage to search a risk factor or a possible blood donor contaminated with HTLV-I virus. We selected an HTLV-I seropositive donor whose RBC participated to the patient's transfusion. This woman from Martinique island was a regular donor in our blood center and a second investigation was initiated to examine the patients transfused with the blood products issued from her previous donation. Nine were identified and controlled among them a patient who has received a RBC was found HTLV-I seropositive. An evaluation of the infectivity of the different blood products according to their type and specificity has been done. These data confirm that transmission of the HTLV-I is possible through donation of healthy seropositive donor and can induce the development of associated pathology, and prove the importance of screening blood donors for HTLV-I antibodies.

Adult↗
PubMed1990

Effect of D ala2 metenkephalinamide on feline jejunal and ileal water and electrolyte transport.

The aim of this investigation was to compare the effect of an opioid, D ala2 metenkephalinamide (DAMA), on net jejunal and ileal water and electrolyte fluxes using the gut perfusion technique in the anesthetized cat. Intestinal transport was measured during intravenous infusion of serial doses of 2, 6, and 18 micrograms.kg-1.h-1 of DAMA in 6 cats. Each cat was its own control during an intravenous infusion of 150 mmol/l NaCl preceding the first dose of peptide and following the last dose of DAMA. Both jejunal and ileal segments were isolated by inflated balloons and were studied at the same time. Fifteen ml of an iso-osmolar test solution with hypo-osmolar ion contents and complementary mannitol were administered in the upstream tube and collected 1 h later in the downstream tube. In the jejunum, water secretion was dose-dependently reversed to an absorption from a control value of +0.5 +/- 0.4 to -0.83 +/- 0.5 ml.h-1.10 cm-1; in the ileum, water absorption was increased from -0.5 +/- 0.3 to -1.5 +/- 0.2 ml.h-1.10 cm-1. The net absorption of all electrolytes, ie sodium, chloride, bicarbonate, potassium and calcium also increased during peptide administration. However, a qualitative difference in the ion transport was observed between the jejunum and the ileum.

Animals↗
PubMed1990

[The treatment of imported Plasmodium falciparum malaria with halofantrine. Apropos of 59 case reports (corrected and republished article orginally printed in Med Trop (Mars) 1990 Jan-Mar;50(1):113-7)].

59 cases of Plasmodium falciparum malaria fever occurring in non-immune Caucasian subjects having got a correct chemoprophylaxis by chloroquine were treated by halofantrine (HALFAN). They were given 1500 mg divided in 3 doses of 500 mg every 6 hours from D1 to D8. All them were back from a malarial highly endemic zone with chloroquine resistance. Analysis of the main biological and clinical efficiency parameters displayed very satisfactory results: disappearances of fever (mean 22 H) and parasitemia (mean 36 H) are short. After two months of monitoring, no malaria recrudescence was noted. With an efficacy of 10 p.c. associated to a noticeable clinical and biological tolerance Halofantrine is a first-class treatment of chloroquine resistant malaria fever.

Adolescent↗
PubMed1985

Capsaicin in adult frogs: effects on nociceptive responses to cutaneous stimuli and on nervous tissue concentrations of immunoreactive substance P, somatostatin and cholecystokinin.

Adult frogs (Rana esculenta) were given subcutaneous injections of 10, 20, 30, 50 and 100 mg/kg capsaicin in sequential order over 5 days, or the vehicle only. The nociceptive thresholds to electrical, thermal and chemical stimuli were measured before, and 1, 5 and 24 h after each injection. Capsaicin was followed by a dose-related reduction of nociceptive responses to all stimuli, but these effects lasted for only 1-5 h after the given injection. Water/acetic extracts of undivided brains and spinal cords were prepared at the corresponding time periods for the radioimmunoassay of peptides. Spinal cord concentrations of immunoreactive substance P were essentially unaffected by capsaicin, while those of immunoreactive somatostatin were significantly increased after the second for fourth injections (20, 30 and 50 mg/kg) of capsaicin. Brain extracts showed an increase of somatostatin and substance P concentrations after the dose of 50 mg/kg. In an additional experiment, immunoreactive substance P, somatostatin and cholecystokinin were measured in tissue samples taken at 2 and 10 min, and 1, 5 and 24 h after a single dose of either 50 mg/kg capsaicin or the vehicle. The only significant effect of capsaicin was an increase of immunoreactive somatostatin concentration in brain homogenates at 5 h, while the vehicle in itself elicited major variations of all three peptides in spinal cord and/or brain. These results indicate that capsaicin reduces the nociceptive responses to cutaneous stimuli in adult frogs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Pesticide-containing diets augment anti-sheep red blood cell nonreaginic antibody responses in mice but may prolong murine infection with Giardia muris.

The effects of oral ingestion of different pesticides (lindane, phosalone, carbaryl) and of a polychlorinated biphenyl (pyralene) on nonreaginic antibody production in BALB/c mice and also on the duration of Giardia muris infection have been studied using the animal model of this disease. Only lindane and carbaryl produced significant effects on systemic antibody production following oral immunization with sheep red blood cells (SRBC). Lindane ingestion led to a twofold increase in IgG2b antibody titer to SRBC (P less than 0.05) and carbaryl significantly increased both IgG1 and IgG2b titers. No reduction was seen in the synthesis of any antibody class. The effect of feeding with lindane was to increase the duration of giardiasis significantly (P less than 0.002), and these mice developed systemic anti-Giardia antibodies more frequently than Giardia-infected mice on normal diets. These results suggest that in the doses used these pesticides may increase systemic antibody responses to orally ingested antigens, and by inference that spontaneous elimination of giardiasis is independent of the systemic nonreaginic antibody response to the parasite.

Animals↗
PubMedDate not supplied

Secondary immune response to oral and nasal rough mutant strains of Salmonella typhimurium.

The variations in anti-Salmonella typhimurium antibody levels was measured in BALB/c mice which had been orally and nasally vaccinated with S. typhimurium live mutants of different lipopolysaccharide lengths. Together with the demonstration of immunological memory, the intensity of the secondary response was correlated with the length of the polysaccharide chain at intestinal and serum levels. Nasally administered antigen seemed to be at least as immunogenic as when orally administered.

Administration, Intranasal↗