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Biomedical subjects

A Bernard

Publications and source records attributed to A Bernard.

At least 433 records · Page 24Linked to original sources
PubMed1988

Recurrent t(11;22) breakpoint mapping by chromosome flow sorting and spot-blot hybridization.

The breakpoint of the recurrent t(11;22) translocation, one of the most frequent chromosome anomalies encountered in human population, always involves bands 11q23.2 and 22q11.2. The involvement of the C lambda locus of the immunoglobulin lambda gene cluster on chromosome 22 has been suggested: however, in situ hybridization experiments have yielded conflicting results. In order to solve these discrepancies by another approach, we have used bivariate flow sorting to separate the chromosomes of interest and to map the specific breakpoints by direct spot-blot hybridization with the gene-specific radiolabelled DNA probes, Alu, V lambda, ets. The results showed unambiguously that in the t(11;22) patient analysed, a set of C lambda and V lambda genes was translocated to the der(11) chromosome. Since V lambda genes are situated proximally to C lambda genes, we demonstrate that, in the case studied here, the chromosome 22 breakpoint is not located within or even immediately close to the C lambda region.

Cell Line↗
PubMed1988

Intermolecular complexes between three human CD1 molecules on normal thymus cells.

The first cluster of differentiation (CD1) defines at least three distinct human thymic cell-surface differentiation antigens-CD1a, CD1b, and CD1c. We looked for structural homology of the three CD1 heavy chains at their peptide level by two-dimensional peptide maps. We show here that the CD1a Mr 49,000 heavy chain and the CD1b Mr 45,000 heavy chain appear to be more homologous to each other than to the CD1c Mr 43,000 heavy chain and that only one tyrosil peptide is common to the three heavy chains. Study of the CD1 heavy chains from several individuals reveals a very limited polymorphism of these molecules. We also demonstrate here that CD1a or CD1a-like molecules and other CD1 molecules can form intermolecular complexes on the surface of normal thymus cells. Molecules that are structurally very similar to CD1a molecules are associated noncovalently either with CD1c molecules or with CD1b molecules, and only CD1a molecules can associate covalently with CD8 molecules. In contrast, we could not find these intermolecular complexes on the surface of leukemic T-cell lines in culture.

Antibodies, Monoclonal↗
PubMed1988

Osmotic response of oocytes using a microscope diffusion chamber: a preliminary study comparing murine and human ova.

The hydraulic conductivity (Lp) of the plasma membrane determines how cells respond to the stresses of dehydration encountered during cryopreservation. We have used a microscope diffusion chamber which allows for direct real-time observation of the dynamic osmotic response of individual cells in microvolume suspension to compare the Lp of murine and human unfertilized ova. In this system, the response of an individual cell to the induced osmotic imbalance is documented via a series of photomicrographs or videotape; from these data the Lp can be computed. Donated human preovulatory oocytes were compared with macroscopically normal human ova, 43 hr after insemination, which had failed to fertilize (Ff) and with murine ova collected 13 hr post human chorionic gonadotropin injection. The permeability coefficients were 0.65 +/- 0.43, 0.84 +/- 0.39, and 0.36 +/- 0.07 micron3/micron2/atm/min. The results suggest that it may be possible to use Ff ova for experiments to design suitable cryopreservation procedures.

Animals↗
PubMed1988

Comparison of signals delivered through CD3 and CD2 for T-cell activation: the role of calcium influx and interleukin 1.

In the absence of monocytes, resting T lymphocytes extensively purified from human peripheral blood failed to proliferate when stimulated with a mixture of calcium ionophore, which elevates intracellular calcium levels, and TPA, which activated protein kinase C. A third signal, i.e., the triggering via CD3 or CD2 molecules, was necessary in order to observe proliferation. These highly purified T cells required the presence of monocytes in both CD3 and CD2 systems for their proliferation. Exogenous interleukin 1 clearly substituted for monocytes in CD2- but not in CD3- triggered T-cell proliferation. In contrast, the effect of CD2 and CD3 antibodies on Ca++ influx was apparently not dependent on the presence of monocytes. In the presence or absence of the monocytes, CD3, as well as certain combinations of CD2 monoclonal antibodies including the D66 monoclonal antibody, were able to increase the intracellular calcium concentration as measured by Quin 2 fluorescence. EGTA, a Ca++ chelator, completely inhibited CD2- and CD3- mediated T-cell proliferation, indicating that calcium uptake is necessary during the T-cell proliferation. The addition of TPA abrogated the inhibitory effect of EGTA and completely restored the response of the T cells stimulated by CD3, but not by CD2, monoclonal antibodies. In the CD2 pathway, EGTA-inhibited proliferation of T cells could be completely restored by addition of exogenous interleukin 2 as well as exogenous recombinant interleukin 1. Our results indicate that EGTA inhibits the production of interleukin 1 but has no direct effect on either interleukin 2 production or on Tac antigen expression. In this system, recombinant interleukin 1 alpha demonstrated a more potent ability for restoring the T-cell response than did recombinant interleukin 1 beta. These results suggest that interleukin 1 could act as a potent costimulatory factor in the non-antigen-specific T-cell activation.

Antibodies, Monoclonal↗
PubMed1988

Hyperinsulinemia induced by canine distemper virus infection of mice and its correlation with the appearance of obesity.

1. Weanling Swiss mice surviving an acute infection with canine distemper virus were persistently infected. Among these mice, up to 30% had hyperinsulinemia and this was followed by an obesity syndrome. 2. Analysis of the lipid composition of various organs revealed that compared to control animals, the obese had an accumulation of triglycerides in both liver and adipose tissue. 3. Studies on the lipid metabolism using a number of radioactive lipid precursors showed a specific accumulation of the triglycerides of the obese animals. 4. A decrease of lipogenesis was observed in white adipose tissue of obese mice. Glycogenesis and serum glucose levels were unaffected during obesity. 5. The model of canine distemper virus-induced obesity is compared with other experimental models.

Adipose Tissue↗
PubMed1988

A randomized comparative study of purified follicle stimulating hormone and human menopausal gonadotropin after pituitary desensitization with Buserelin for superovulation and in vitro fertilization.

Twenty patients entered a randomized, crossover study of purified follicle-stimulating hormone (pure-FSH) or human menopausal gonadotropin (hMG) superovulation, 2 ampules per day after pituitary desensitization with the luteinizing hormone-releasing hormone (LH-RH) analogue Buserelin (D-Ser tBu6 LH-RH 1-9 ethylamide) nasal spray. There were no cycles cancelled. Six patients conceived (five on pure-FSH, one on hMG). There were 24.2 +/- 2.5 (mean +/- standard error of the mean [SEM]) ampules of pure-FSH and 24.3 +/- 3.6 ampules of hMG stimulation required. There were similar numbers of preoperation follicles: 6.9 +/- 1.0 on hMG and 6.6 +/- 1.1 on pure-FSH, of oocytes collected; 8.5 +/- 1.4 on hMG and 5.8 +/- 1.4 on pure-FSH, and of pre-embryos achieved; 5.1 +/- 0.9 on hMG and 3.4 +/- 1.0 on pure-FSH; on either treatment. The fertilization rate on hMG was 60% and on pure-FSH was 55%. Pre-embryo transfer rates were 3.2 +/- 0.3 in the hMG group and 2.7 +/- 0.4 in the pure-FSH group. There were no differences in serum FSH, LH, estradiol, or progesterone levels between the hMG and pure-FSH groups. Mean +/- SEM luteal phase length was 10.6 +/- 0.4 days in the nonpregnant cycles.

Adult↗
PubMed1988

[Peroperative bronchospasm during surgery of hydatid cysts].

A case is reported of isolated bronchospasm occurring during the removal of two hydatid cysts in the same patient at the same time. This 44 year old man already had had a hydatid cyst removed one year previously; no complication had occurred at the time. The patient had a past history of asthma, easily treated by salbutamol spray. All went well until the first cyst was manipulated: the ventilating pressures rose, and wheezing rhonchi appeared in both lung fields. This bronchospasm was resistant to an increase in anaesthetic depth, to salbutamol, terbutaline, steroids and 3% halothane for 15 min. It however disappeared completely as soon as the cyst was removed. There were no other signs of an anaphylactic reaction. The same thing occurred during the removal of the second cyst. Postoperative investigations showed the patient to be sensitized to house dust and mites. His asthma is confirmed. Allergologic tests showed no reaction with the anaesthetic drugs used, but a hypersensitivity to the echinococcal antigens. The bronchospasm was probably due to the increased bronchial sensitivity of this patient.

Adult↗
PubMed1988

The renal uptake of proteins: a nonselective process in conscious rats.

The selectivity of the renal reabsorption of proteins has been investigated by competition experiments in conscious rats. The animals were intravenously injected with increasing doses of proteins over a wide range of net charge and size, including lysozyme, cytochrome C, metallothionein, beta 2-microglobulin, retinol-binding protein, albumin and IgG. The urinary excretion of exogenous proteins injected concomitantly (human beta 2-microglobulin, retinol-binding protein, albumin and/or egg white lysozyme depending on the experiment) and of rat beta 2-microglobulin, albumin and IgG was determined with specific immunoassays. The results show that low molecular weight cationic proteins and low or high molecular weight anionic proteins can increase each other's urinary excretion. Several observations strongly suggest that these effects result from a competitive inhibition of renal uptake. The phenomenon is dose-related in most cases and, as evidenced by cytochrome C injection, transient, reproducible and saturable. In addition, the injected proteins induce a tubular type proteinuria irrespective of their net charge and size. In the case of cationic proteins, this finding excludes the possibility of an enhanced glomerular permeability due to a partial neutralization of the glomerular polyanion which, as demonstrated with protamine sulfate, entails a glomerular type proteinuria. These quantitative data on the mutual inhibition of renal uptake of a wide spectrum of specific proteins lead us to challenge the concept of charge- and size-selective tubular reabsorption of proteins, and to postulate that proteins filtered through the glomeruli are taken up by common tubular endocytotic sites irrespectively of their physicochemical features. As demonstrated by the ability of beta 2-microglobulin and IgG to inhibit the uptake of lysozyme, the affinity of a protein for reabsorption sites is not simply related to its size and net positive charge. Evidence is also presented that proteins, when administered intravenously at high doses, induce a lysosomal enzymuria most likely reflecting a stimulated exocytosis.

Absorption↗
PubMed1988

HLA class I molecules are associated with CD1a heavy chains on normal human thymus cells.

The molecules encoded by the major histocompatibility complex play a pivotal role in regulatory interactions between cells of the immune system, which can result in the activation and function of T cells. The function of the CD1 molecules, which are homologous to the major histocompatibility complex-encoded molecules but are encoded on human chromosome 1, is not known. HLA class I molecules and CD1a heavy chains share the ability to associate with several different cell-surface molecules. We show here, by several technical approaches, that HLA class I molecules are associated with CD1a heavy chains on the surface of normal thymus cells. The functional significance of this association during T-cell differentiation is discussed.

Antibodies, Monoclonal↗
PubMed1988

Studies on the human chromosome 3 centromere with a newly cloned alphoid DNA probe.

Starting from a chromosome-specific DNA library, we have isolated a human chromosome-specific satellite DNA sequence. This sequence of 635 base pairs (bp) consists of 3.7 alpha DNA monomers of 170-171 bp. Under high stringency it hybridizes to the centromere of chromosome 3 in a region composed of 2,750 bp tandem repeats characterized by the regular spacing of Hind III and TaqI restriction enzyme recognition sites. It has diverged and undergone amplification after the human speciation. The amplification allows an easy monitoring of the chromosome 3 centromere by in situ hybridization with a nonradioactive probe.

Animals↗
PubMed1988

[Multiple proximal coronaro-pulmonary fistulae. Review of the literature apropos of a new case].

The authors report a new case of multiple proximal coronaro-pulmonary fistula between right coronary arteries, anterior interventricular artery and the trunk of the pulmonary artery, in a 64 year-old female patient with chest pain and a continuous murmur located in the third left intercostal space. The coronary steal is demonstrated by a myocardial scintigraphy during stress with return to normal after surgical ligation. A review of the literature enabled to find 33 cases of this major congenital anomaly of the coronary arteries, defined as an abnormal communication between at least two main coronary vessels and the trunk of the pulmonary artery. This results in a left-right shunt, usually minor without any repercussions on the right cavities and pulmonary pressures. The entire clinical, electrocardiographic, radiological, sonographic, scintigraphic, haemodynamic and angiographic picture is reported for these 33 cases. A physiopathological discussion is proposed. The course of this disease is usually favorable (only one case of myocardial infarction was published, without cardiac failure. Osler's endocarditis or sudden death); this seems to authorize simple monitoring as a logical therapeutic approach except when a myocardial ischemia secondary to coronary steal is demonstrated, imposing a surgical correction.

Arterio-Arterial Fistula↗
PubMed1988

[Left coronaro-ventricular microfistula].

Microfistulae between coronary arteries and left ventricle have long been regarded as mere curiosities, but their frequency seems to have been underestimated. A review of 2,520 consecutive coronary arteriographies performed in adults has yielded 34 cases. In most of the 28 patients without infarction or valve disease, the symptoms were suggestive of coronary pathology. Signs of ischaemia were found at electrocardiography in 19 of these 28 patients, and exercise tests or myocardial scintigraphy were positive in 2 out of 3 cases. Patients' mean age was 53.4 years. The coronary arteriographic diagnosis was usually easy when technical conditions were perfect. The division of patients into two groups according to the presence or absence of significant coronary lesions revealed that the "isolated microfistulae" group was primarily composed of women (19/21). It is generally accepted that these fistulae are of embryonic origin, but their relation to atherosclerosis needs to be determined. The causes of ischaemic manifestations (coronary artery steal, global disturbances of myocardial microcirculation) are considered. Treatment is essentially medical, surgery being exceptional. Prognosis is habitually favourable (mean follow-up 28.3 months in our series). Thus, microfistulae between coronary arteries and left ventricle usually present as angina-like symptoms in women in their fifties who are free from atheromatous disease. They are found in more than 1 p. 100 of coronary arteriographies in adults, i.e. 8 p. 100 of "normal" coronary arteriographies. Their origin, the mechanisms of their symptoms and their relationship with the "so-called healthy coronary arteries angina" are obscure.

Coronary Angiography↗
PubMed1988

Progesterone and oestradiol levels and cytoplasmic receptor concentrations in the human myometrium at term, before labour and during labour.

Progesterone (P) and oestradiol (E2) cytoplasmic receptor levels in the myometrium of 12 women, who underwent cesarean section at term were determined by means of an exchange assay. Six of the women had an elective cesarean section, and the other six were in active labour when the operation was performed. Both the P and the E2 receptor concentrations were significantly higher in the myometrium of those women who were in labour. The plasma P and E2 levels did not change before labour and during labour. The myometrial E2 concentrations were also similar in both groups. The myometrial P concentration was lower in the labour group, but the difference was not statistically significant. This study is the first which compares the steroid receptor levels at term before labour and during labour in human myometrium, although only the unbound and the cytosol receptor levels were determined. The change of levels in receptor concentrations could be a sign of the decrease of the P dominance in the myometrium during labour.

Cesarean Section↗
PubMed1988

The limitations in utilizing phenotypic markers to detect minimal residual disease in acute leukaemias (AL).

So far, in spite of the evergrowing number of available anti-leucocyte mAb, phenotypic markers proved to be of limited value for the detection of a minimal residual disease in leukemias. The question is to detect malignant leucocytes in a normal hematological environment. However no marker is specific for the malignant state perse. In addition, many markers are not absolutely specific of a given lineage of differentiation. Consequently the precise characterization of a leukaemic population must rely on a battery of markers. Finally, normal leucocyte populations are much more heterogeneous than initially thought. Prospects for efficient methods are discussed; they rely mainly on the possibilities to enrich the malignant clone and to induce its in vitro expansion.

Antibodies, Monoclonal↗