PubMed Health⌕ Search

Biomedical subjects

H Jouin

Publications and source records attributed to H Jouin.

At least 19 recordsLinked to original sources
PubMed1992

Plasmodium chabaudi p68 serine protease activity required for merozoite entry into mouse erythrocytes.

To define the role of malaria parasite enzymes during the process of erythrocyte invasion, we have developed an in vitro serum-free invasion assay of mouse erythrocytes by purified Plasmodium chabaudi merozoites. The sensitivity of a merozoite-specific serine protease (p68) to various inhibitors and the effect of these inhibitors on invasion indicate a crucial role for p68. The substrate specificity of the purified enzyme has been partially defined using fluorogenic peptides. Consistent with this, in vitro incubation of mouse erythrocytes with the merozoite enzyme led to the cleavage of band 3 protein. The possible implication of erythrocyte band 3 truncation for the successful entry of the merozoite into the erythrocyte is discussed.

Animals↗
PubMed1991

Dynamics of lymphocytes and inflammatory cells recruited in liver during murine listeriosis. A cytofluorimetric study.

During primary infection of mice by Listeria monocytogenes, bacterial elimination is dependent on the recruitment of myelomonocytic cells in the infectious foci and the activation of their bactericidal mechanisms through cytokines secreted by Listeria-specific T lymphocytes. The immune events occurring in the liver, one of the main infected organs, have not yet been studied in detail. In the present quantitative study, we describe the dynamics of recruitment of cells belonging to the lymphoid or myelomonocytic lineages in the liver. The different cell populations mobilized into the liver were isolated each day during the course of a sublethal L. monocytogenes infection and their phenotype was characterized by flow cytometry. Three distinct phases of recruitment were observed. 1) During the first day of infection, 17 x 10(6) lymphomyeloid cells were recruited in the liver with a predominance of myelomonocytic cells; 51% of the incoming cells were M1/70+; the NK cell population (detected by the 4D11 antibody) also increased transiently at this period. 2) From day 3 to 5, a high number of myelomonocytic cells infiltrated the liver (13 x 10(6) M1/70+ cells); most of these cells were macrophages (as detected with the macrophage-restricted antibody FA/11 or observed after May-Grünwald Giemsa staining); the antigranulocytic antibodies 7/4 and RB6.8C5 were found to label these mononuclear phagocytes at this period of infection. A subpopulation of Thy-1+ cells (16%) was found to be labeled by the RB6.8C5 antibody in normal liver and, at day 5 and 6, all Thy-1+ cells also bound the RB6.8C5 mAb.3) From day 5 onward, two waves of phenotypically distinct T lymphocytes were observed; the number of CD8+ T lymphocytes (15 x 10(6) cells) increased first at day 5 and peaked on day 7; CD4+ T lymphocytes (6.2 x 10(6) cells) were then recruited with a 2-day delay (on day 7) in the liver.

Animals↗
PubMed1991

Human chromosome 16 encodes a factor involved in induction of class II major histocompatibility antigens by interferon gamma.

Interferon gamma (IFN-gamma) induces expression of class II major histocompatibility complex (MHC)-encoded antigens in immunocompetent cells. To gain further insight into the mechanism of this induction, we prepared somatic cell hybrids between different human cell lines and a murine cell line, RAG, that does not express murine class II MHC antigens before or after treatment with murine IFN-gamma. Some of the resulting cell hybrids express murine class II MHC antigens when treated with murine IFN-gamma. This inducible phenotype is correlated with the presence of human chromosome 16. It has been shown previously that the induction of class I MHC antigens by human IFN-gamma in human-rodent hybrids requires the presence of species-specific factors encoded by chromosome 6, which bears the gene for the human IFN-gamma receptor, and chromosome 21, whose product(s) is necessary for the transduction of human IFN-gamma signals. In this report, we show that the induction of murine class II MHC antigens by human IFN-gamma in the human-RAG cell hybrids requires, likewise, the presence of human chromosomes 6 and 21, in addition to chromosome 16. In some of these hybrids, when all three of these human chromosomes were present, induction of cell-surface HLA-DR antigens was also observed. Our results demonstrate that human chromosome 16 encodes a non-species-specific factor involved in the induction of class II MHC antigens by IFN-gamma.

Animals↗
PubMed1991

[Anorectal manometry and ileo-anal anastomosis].

Seventeen patients (12 ulcerative colitis, 5 familial adenomatous polyposis) underwent proctocolectomy and ileal J pouch anastomosis. Anal manometry with determination of maximum tolerable volume and a liquid continence test were perform before ileo-anal anastomosis, before closure of the loop ileostomy and 12 months after closure of the loop ileostomy. All patients were continent during the daytime less 12 months after proctocolectomy. The mean stool frequency was 5 stools per day in our 17 patients. A significant increase in maximum tolerable volume and in the liquid continence test was observed during the first year after closure of the ileostomy. Anal manometry is unnecessary after ileoanal anastomosis, but preoperatively, this test is able to exclude some patients with low anal pressure.

Adenomatous Polyposis Coli↗
PubMed1990

Isolation and flow cytometric analysis of the free lymphomyeloid cells present in murine liver.

Recruitment of circulating lymphomyeloid cells in the liver during infection often plays a critical role, mediating control or exacerbation of the pathogen growth. This paper describes a simple and rapid technique to recover these lymphomyeloid cells from a normal or an infected liver. After portal perfusion with saline buffer, the liver is gently dissociated on steel screens and the resulting cell population spun in 35% Percoll in 100 IU/ml Calciparine to remove all nuclei and cell debris: the recovery of a pure liver lymphomyeloid cell population is usually achieved in 40-60 min. Phenotypic and functional analysis could then be easily carried out on this cell population. This methodology was applied to normal mouse liver: flow cytometric analysis of the purified free lymphomyeloid cells showed the presence of T lymphocytes (46% +/- 3 with a CD4/CD8 ratio of 2.8), B lymphocytes (20% +/- 2 IgG and 30% IgM positive) and myelomonocytic cells (14% +/- 2 complement receptor type III positive).

Animals↗
PubMed1990

Activation of a beta-galactosidase recombinant provirus: application to titration of human immunodeficiency virus (HIV) and HIV-infected cells.

A quantitative bioassay for human immunodeficiency viruses has been developed on the basis of the ability of the tat gene to transactivate the expression of an integrated beta-galactosidase gene in a HeLa-CD4+ cell line. Infection by a single virion of HIV-1 or HIV-2 corresponds to a unique blue syncytium or a cell cluster detected after fixation and addition of 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (a beta-galactosidase substrate). The number of infected lymphoid cells in a culture (stimulated human peripheral blood lymphocytes and cell lines) can also be quantified by cell-to-cell transmission of HIV into the HeLa-CD4(+)-beta-galactosidase monolayer. Infections by simian immunodeficiency viruses are similarly detected. This assay has been used to determine the dose response of drugs, the half-life of HIV at 37 degrees C, and the appearance of infectious particles after virus infection.

Blotting, Southern↗
PubMed1990

[Socioprofessional consequences of Crohn disease].

To evaluate evolutivity and social repercussions of Crohn's disease, the same gastroenterologist interviewed 151 out of 197 patients with Crohn's disease (77.5 percent) who had been hospitalized from 1964 to 1986 in our unit. The other 46 could not be traced or refused to participate. There was no difference regarding age, sex, duration of illness, pattern of lesions and operations between the two groups. At the time of observation, mean follow-up was 7.8 years and two thirds of the patients had inactive disease. During the previous year, the course of the disease was quiescent in 50 percent of all patients; this rate increased with duration of follow-up and time from surgery. A constant rate of stable course was observed (20 percent) irrespective of duration of disease and time of surgery. The interviews were compared with those obtained from an age and sex-matched group of 70 previously healthy subjects admitted to the hospital for less than one month. The education and socioeconomic levels were higher in patients with Crohn's disease than in controls, in spite of the fact that 25 percent of patients whose disease begun during scholarship complained of difficulties at school, and nearly 20 percent of all patients were partially or totally unable to work. Sports and cultural activities were the same in Crohn's disease and in the control group. Tobacco intake was slightly higher at time of diagnosis but it was equal in both groups at the time of the interview. Non allopathic advice or treatment were sought by 48 percent of Crohn's disease patients (7 percent in controls).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Is there an increased incidence of adenomatous polyps in breast cancer patients?

Using flexible proctosigmoidoscopy, the incidence of adenomatous polyps was studied in 161 patients previously operated on for breast cancer and also in 147 hospitalized controls not presenting with colorectal symptoms. The acceptance and tolerance of the examination were good in both populations. The mean age and length of the colons explored were not statistically different for the two groups. The incidence of adenomas was high in the breast cancer group (14.2%) in comparison to the control group (4.7%) (P less than 0.01). This strong incidence especially concerned very small polyps with a diameter smaller than 3 mm. There were also two polyps with superficial carcinomas in the breast cancer group. Breast cancer does indeed seem to represent a condition with a high risk of colorectal adenomas. Our results prompt us to propose the adoption of systematic screening measures and a surveillance schedule as soon as the breast cancer is found.

Adenoma↗
PubMed1989

Visualizing interleukin 2 gene expression at the single cell level.

To analyze the expression of the interleukin (IL)2 gene at the single cell level, we have constructed a chimeric gene in which the regulatory sequences from the mouse IL2 gene were fused 5' proximal to the coding region of the Escherichia coli beta-galactosidase (lacZ) gene. Once stably introduced into a T cell hybridoma, the IL 2-lacZ reporter gene was shown to display a pattern of induction similar to the one observed for the resident IL 2 gene. Two points emerged from monitoring IL 2 expression for the resident IL2 gene. Two points emerged from monitoring IL 2 expression at the single cell level. First, upon activation the expression of the IL2-lacZ gene appears asynchronous. Second, at the peak of induction the percentage of beta-galactosidase+ cells never reached 100% and the level of beta-galactosidase reached among positive cells was highly heterogeneous within a cloned population of T cells. In combination with the possibility to sort viable lymphocytes according to lacZ expression, the IL2-lacZ reporter gene described herein should provide a way to isolate somatic cell mutants deficient in signal transduction by the T cell antigen receptor complex.

Animals↗
PubMed1989

Characterization of human IFN-gamma response using somatic cell hybrids of hematopoietic and nonhematopoietic origin.

A panel of 27 rodent-human somatic cell hybrids composed of cells of hematopoietic (nonadherent cells) and nonhematopoietic origin (adherent cells) was used to identify the chromosomes involved in the biological response to human IFN-gamma (Hu-IFN-gamma). We found that the stimulation of class-I histocompatibility antigen expression correlates with the presence of human chromosomes 6 and 21 in adherent cell hybrids, while human chromosome 6 alone is sufficient in nonadherent hybrids. Scatchard analysis of the binding of radiolabeled Hu-IFN-gamma to nonadherent cell hybrids gave a Kd value similar to that found on human cell lines. Induction of a reporter gene placed under the transcriptional control of the interferon responsive sequence (IRS) in adherent cell hybrids requires both chromosomes 6 and 21. The antiviral protection by Hu-IFN-gamma in adherent cell hybrids was reached at physiological doses (2 units/ml) when human chromosomes 6 and 21 were present, while higher doses of Hu-IFN-gamma (5000 units/ml) were required for hybrids lacking chromosome 21. Thus, we demonstrate that differences exit in the response to Hu-IFN-gamma depending on the origin of the cell type.

Animals↗
PubMed1988

Plasmodium falciparum: molecular analysis of a putative protective antigen, the thermostable 96-kDa protein.

A group of three Plasmodium falciparum antigens of distinct pI, migrating with an apparent MW of 96 kDa has been previously identified as a target of protective immunity both in humans and in monkeys (Jouin et al. 1987, Dubois et al. 1987). These antigens are produced during the late stages of asexual intraerythrocytic development. One of these 96-kDa proteins, the 96 tR, has a pI of 5.25, is thermostable, and is released in the culture supernatant (Jouin et al. 1987). We report here the cloning and expression in Escherichia coli of the gene coding for this antigen. Antibodies raised to the recombinant 96 tR immunoprecipitated exclusively the 96 tR, indicating that the other two antigens of 96 kDa are the product(s) of distinct gene(s). Northern and Southern blots as well as DNA sequencing of the gene showed that the 96 tR antigen is identical to proteins identified in other laboratories as the glycophorin binding protein GBP 130 (Perkins 1984, Ravetch et al. 1985) and Ag 78 (Bianco et al. 1987). The 96-kDa antigen is produced at the trophozoite stage and more actively in the schizonts. It is released in the culture supernatant at the time of schizont rupture, together with two minor products, forming a characteristic triplet. This triplet was also detected in immunoblots of merozoites. An approximate quantification on immunoblots indicated that the largest proportion of the protein is found in the culture supernatant, a minor fraction being loosely associated with merozoites. By immunofluorescence and immunoelectron microscopy, intense signals were observed in the erythrocyte cytoplasm. The 50-amino acid repeats were found in all strains examined, the protein showing some size polymorphism. The antigen was detected in the serum of infected monkeys as well as in that of infected humans.

Amino Acid Sequence↗
PubMed1988

[Gastroesophageal reflux in asthmatic and chronic bronchitis patients].

To determine the relationship between gastroesophageal (GE) reflux and pulmonary disease, we studied 21 asthmatics, 30 chronic bronchitics, 6 patients with GE reflux and no pulmonary symptoms, and 10 control subjects; GE reflux was diagnosed by pH monitoring and GE scintiscanning. Frequency of GE reflux in the asthmatics was 57%; in chronic bronchitis it was 56%. Pulmonary function tests did not show any differences between patients with or without reflux. The GE reflux episodes were more numerous but shorter in asthmatics than in chronic bronchitis. Patients with digestive symptoms alone were no different from chronic bronchitis with respect to reflux. The mechanism whereby reflux triggers pulmonary problems was investigated using the following 2 tests: scintiscan for pulmonary aspiration, and esophageal acid infusion (0.1N HCI). Six pulmonary aspirations were detected. Only asthmatics, with or without reflux, showed any significant variations in maximal expiratory flow at 50% and 25% of VC after HCI infusion. Thus, our results show that asthmatics differ from bronchitis patients by the characteristics of their reflux.

Adult↗
PubMed1987

Characterization of a 96-kilodalton thermostable polypeptide antigen of Plasmodium falciparum related to protective immunity in the squirrel monkey.

Protective immunity against Plasmodium falciparum malaria in the squirrel monkey (Saimiri sciureus) is, in part, antibody mediated. We have previously shown that polypeptides of 41, 76, and 96 kilodaltons (kDa) are specifically immunoprecipitated with monkey sera which are protective in passive transfer experiments. We report here that three different 96-kDa polypeptides, of pI 5.15, 5.25, and 5.35, can be visualized when parasite extracts are analyzed in bidimensional gels. Only one of them (of pI 5.25) was stable after being heated at 100 degrees C for 5 min. The 96-kDa thermostable polypeptide of pI 5.25 was immunoprecipitated by protective monkey sera and by sera from adult humans living in hyperendemic areas and thus seems to be correlated with humoral protective immunity. This antigen was found in culture supernatants at the time of schizont rupture. It was synthesized during the schizont stage and is apparently not a glycoprotein.

Adult↗
PubMed1987

Gastroesophageal reflux in patients with asthma and chronic bronchitis.

To determine the relationship between gastroesophageal (GE) reflux and pulmonary disease, we studied 21 asthmatics, 30 chronic bronchitics, 6 patients with GE reflux and no pulmonary symptoms, and 10 control subjects; GE reflux was diagnosed by pH monitoring and GE scintiscanning. Frequency of GE reflux in the asthmatics was 57%; in the chronic bronchitics it was 56%. Pulmonary function tests did not show any differences between patients with or without reflux. The GE reflux episodes were more numerous but shorter in asthmatics than in chronic bronchitics. Patients with digestive symptoms alone were no different from chronic bronchitics with respect to reflux. The mechanism whereby reflux triggers pulmonary problems was investigated using the following 2 tests: scintiscan for pulmonary aspiration, and esophageal acid infusion (0.1N HCl). Six pulmonary aspirations were detected. Only asthmatics, with or without reflux, showed any significant variations in maximal expiratory flow at 50% and 25% of VC after HCl infusion. Thus, our results show that asthmatics differ from chronic bronchitics by the characteristics of their reflux.

Adult↗