PubMed Health⌕ Search

Biomedical subjects

J P Valet

Publications and source records attributed to J P Valet.

12 recordsLinked to original sources
PubMed1978

[Thalassemia in French-speaking Quebec residents].

Eighty-five cases of beta-thalassemia minor were found between January 1975 and November 1977 in 18 families of French-speaking Quebeckers without Mediterranean ancestry. Most of the families had settled in Quebec more than 200 years ago, largely in Portneuf county. This is the first report of such a number of cases of beta-thalassemia in this population. Thus, beta-thalassemia minor is a relatively common condition in Quebec and must be considered in cases of microcytic anemia without evidence of iron deficiency. The hematologic findings were similar to those reported in the past in other populations. Two cases of delta beta-thalassemia minor (in sisters) are also reported; this is the first report of such cases in French Canadians.

Female↗
PubMed1978

Polystyrene tube immunoradiometric assay for human alpha1-fetoprotein, and its use for mass screening.

We describe a two-site immunoradiometric assay for human alpha1-fetoprotein, with use of antibody-coated polystyrene tubes as solid phase. The sensitivity, precision, and simplicity of this system make it eminently suitable for mass-screening purposes. We currently use it for neonatal detection of hereditary tyrosinemia in the Province of Quebec; measurements are made on blood spotted and dried on paper. This system could be well suited for other mass surveys, such as prenatal screenings for fetal abnormalities.

Amino Acid Metabolism, Inborn Errors↗
PubMed1976

Isolation, composition and reactivity of the neutral glycoproteins from human meconiums with specificities of the ABO and Lewis systems.

Blood-group-specific A1, B, AB, H and Lea neutral glycoproteins were isolated from suitable pools of human normal meconiums by a preliminary fractionation with a cationic detergent at pH5 and 9 (borate), followed by ion-exchange and gel chromatography. The ABH materials have sedimentation coefficients of about 10S-11S, whereas the Lea preparation, not strictly homogeneous, shows a coefficient of 7S. From the detailed analytical data collected, the following relations are deduced between these various substances; they all possess a common peptide core; there are stable ratios of N-acetylglucosamine/N-acetylgalactosamine in the B, H and Lea materials and of N-acetylglucosamine/galactose in A, H and Lea materials, from which the numbers of A and B determinants are estimated. In the ABH substances, the ratio of glucosamine to the sum of threonine and serine is stable. Presumably because of genetic factors, the amount of fucose varies among the different glycoproteins, but it is always definitely lower than in the average cyst substances. Various serological tests and precipitin methods were used to measure the potency, purity and integrity of the preparations, including comparisons between A1 and A2 substances from this source. The Leb activity did not appear as high as it is in glycoproteins from adults and a possible interpretation would be the immature Lewis system as observed on erythrocytes; this could explain their very strong inhibiting power towards iso-agglutinins. This family of substances with various specificities has common features with that prepared from ovarian cysts, but differs clearly on some points.

ABO Blood-Group System↗
PubMed1975

Hepatitis B surface antigen: regional variation in sub-type ratio in the Canadian Red Cross donor population.

A total of 344 sera positive for hepatitis B surface antigen from volunteer blood donors at several Canadian Red Cross centres were subtyped for ad and ay specificity by counterelectrophoresis. Of the 50 sera from Toronto 21 (42%) were ad and 29 (58%) were ay; of the 95 from Montreal 82 (86%) were ad and 13 (14%) were ay; of the 199 from Quebec 179 (90%) were ad and only 20 (10%) were ay. The w and r specificities were also determined in 125 of the samples: 123 were w; the 2 samples of r specificity were from Toronto. On the other hand, among 45 sera from patients with acute hepatitis type B in Quebec 13 (29%) were ad and 33 (71%) ay.

Acute Disease↗
PubMedDate not supplied

[Cellular interaction in the pokeweed-mitogen induced terminal differentiation to polyclonal immunoglobulin production in human B lymphocytes in vitro].

The differentiation of human B lymphocytes in vitro into Ig secreting cells, as measured by a radioimmunoassay rendered specific to IgG and IgM, in response to a polyclonal stimulant, requires the participation of several cellular types. Upon poleweed-mitogen stimulation, B-cell enriched and monocyte containing cell suspensions prepared by elution of nylon wool adherent cells, when mixed with various concentrations of T cells purified by filtration through nylon wool column and depletion of EAC-rosette forming cells, synthesize 5 to 20 times more Ig than non separated lymphocytes. These experiments which demonstrate the cooperation of certain T cells also suggest that other cells eliminated by nylon wool adherence act as suppressor cells. The cooperation of these T cells is independent of their proliferation and can be obtained with allogeneic T cell.

B-Lymphocytes↗
PubMedDate not supplied

[Albumin secreting hepatocytes detected as plaque-forming cells in liquid medium].

Albumin-secretins hepatocytes were detected as plaque-forming cells when incubated in a complete culture medium containing sheep eythrocytes coated with purified anti-albumin, plus anti-albumin serum and complement added at appropriate dilutions. Plaque-formation is observed after incubation at 37 degrees C for 1 h 1/2 between two properly spaced microscope slides sealed with paraffin. Plaque enumeration revealed that 17-18% of normal adult rat lover cells secreted albumin. The assay which is reproductible and highly sensitive is also done in a single step.

Animals↗
PubMedDate not supplied

[Functional studies of T and B lymphocytes].

The means for analysing T-cell activities are very limited. Indeed, the numerical estimation of the changes which take place in human T lymphocytes had to rely solely on the observation of transformed cells (blasts). However, even if various mitogens appear selective for either T of B cells, we know that both types of lymphocytes are ultimately transformed into blasts. This is particularly true in studies conducted on mixtures of T and B cells where stimulated T cells can release substances which act on B cells. On the other hand, studies with purified populations of T or B cells do not express the cellular interactions that occur naturally between these two types of lymphocytes. For all these reasons, it seemed that the estimation of " quanta " of activity unique to T lymphocytes would contribute significantly to our knowledge of this line of cells. We describe a new method of detecting the in vitro stimulation of lymphocytes based on the appearance of cells having the property to cluster several layers of sheep red blood cells (SRBC) around themselves, forming multilayer rosettes (CFC). This formation is temperature-dependent and requires trypanblue-excluding, metabolically active blastoid cells. Non-separated cells as well as purified T cells stimulated with allogeneic leucocytes (MLR), specific antigens or polyclonal mitogens (PWM, ConA) gave rise to CFC. Such multilayer rosettes were not formed by separated B cells. In the MLR, CFC were detected 48 h after beginning of cultures and increased in number thereafter just like thymidine incorporation. The response to ConA and PWM was detected earlier and gave rise to two or three peaks, the first rise in the number of CFC coinciding with the peak of thymidine incorporation, but the maximal increase occurring two or three days later. Treatment of blastoid cells with a serum specific for T cells--but not with an anti-immunoglobulin serum--abolished their ability to form ordinary or multilayer rosettes. When separated, however, on a nylon wool column, CFC were more adherent than the bulk of T cells. It is suggested that CFC form a subpopulation of T cells with distinct characteristics, allowing a direct assessment of membrane changes which take place when T lymphocytes are activated in vitro.

B-Lymphocytes↗