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J D Tissot

Publications and source records attributed to J D Tissot.

At least 19 recordsLinked to original sources
PubMed2001

Human peripheral blood leukocyte engraftment into SCID mice: critical role of CD4(+) T cells.

We examined the influence of donor T lymphocytes on human peripheral blood leukocytes (PBL) engraftment into severe combined immune deficient (SCID) mice. Mice were injected with unfractionated or subset-depleted human PBL, and treated at various times with OKT3, a cytotoxic monoclonal antibody against human CD3(+) T lymphocytes. PBL engraftment, high levels of human Ig, and high incidence of lymphoproliferative disease (lpd) were found in mice transplanted with unfractionated PBL and CD8- or CD14-depleted PBL, and in mice treated with OKT3 at distance from PBL transfer. Animals xenografted with CD3- or CD4-depleted PBL, or treated at transplantation time with OKT3, had very low levels of human Ig and did not develop lpd. PBL engraftment was minimal or absent in these animals, as determined by immunohistochemistry, dot-blot, and RT-PCR analyses. These results demonstrate that the presence of donor CD4(+) T lymphocytes at transplantation time is necessary for observing human PBL engraftment into SCID mice, an essential condition for human Ig production and lpd development.

Animals↗
PubMed2001

[Twelve years of liver transplantation in Lausanne].

From 1988 to June 2000 138 transplantations were performed in 129 adult patients. Actuarial patient and graft survivals have been 80.7% and 75.4% at one year and 67.8% and 63.5% at 10 years. This compares favourably with the statistics of the European Liver Transplant Registry that collected data from more than 30,000 grafts. Over the twelve years of activity, the indications have become more liberal and the techniques have been simplified. The waiting list has therefore grown and some patients are now unfortunately dying before a graft can be found because the number of brain dead donors remains stable. In order to palliate this shortage, older donors are now being accepted even with co-morbidities and/or moderate alterations of the liver function tests. The use of live donors and the split of the best cadaveric grafts for two recipients will also reduce the gap between the demand and the offer.

Actuarial Analysis↗
PubMed2001

[Risk management in the hospital milieu: needs and implications].

Medicine can be dangerous for the patients, the caregivers, the visitors and the environment. Technological progress provides devices and drugs that are always more powerful, more efficacious, but at the same time able to lead to severe side effects. This paper describes the system set up in a university hospital to fulfill legal requirements. Specialists in specific fields build up commissions, which are united in a coordination office. A general policy for the hospital has been decided, but each commission is responsible for managing the risks in its field. The overall philosophy moved from a quality assurance to a quality management system, in which the employee involved in an incident or an accident is no longer considered the only culprit except in cases of obvious violation of established procedures. In order to be efficient, the system must be as simple as possible, and well known, so that collaborators gain confidence in it. Once this cultural revolution is accomplished, quality but also security of the procedures will be improved. Its impact on cost is more questionable, as the system generates running costs which might be higher than the savings it might bring.

Algorithms↗
PubMed2000

[Autologous transplantation of peripheral blood stem cells in the framework of treatment for hematologic neoplasms. II. Determination of CD34+ cells and progenitor colonies].

119 collections of peripheral blood stem cells were performed in 60 patients suffering from various haematological malignancies. One patient was transplanted twice. Peripheral blood stem cell mobilisation was performed using various regimens. A correlation (r = 0.732) was found between the number of peripheral CD34+ cells and the number of CD34+ cells that were collected by apheresis. Furthermore, the number of collected peripheral blood stem cells correlated with the number of colony-forming units (CFU-GM) identified after cell culture (r = 0.607). After transplantation, the duration of neutropenia (> 0.5 x 10(9)/l) was 11.7 days (SD = 3.3) and of thrombocytopenia (> 20 x 10(9)/l) 12.7 days (SD = 6.8). For the whole group, no correlation was observed between the number of CD34+ cells infused and the length of the aplasia. However, when the patients were separated into two groups, according to the amount of CD34+ cells transplanted (< 10 x 10(6)/kg, n = 48 and > 10 x 10(6)/kg, n = 13), a statistically significant but moderate decrease in the duration of neutropenia and thrombocytopenia was observed in patients who received the highest doses of CD34+ cells. Our results confirm the utility of measuring the number of the CD34+ cells in peripheral blood as well as in the product collected by apheresis, but they challenge the place of cultures of progenitor haematopoietic cells. Moreover, the infusion of large amounts of CD34+ cells shortens the duration of the aplasia.

Antigens, CD↗
PubMed2000

[Autologous transplantation of peripheral blood hematopoietic stem cells in the treatment of hematological malignancies. I: patients].

61 autologous transplantations for haematological malignancies have been performed with peripheral blood stem cells in 60 patients. 26 grafts were performed for non-Hodgkin's lymphoma (18 patients were transplanted in first remission, 8 patients after progression or relapse), 13 for multiple myeloma, 7 for Hodgkin's disease and 10 for acute myeloid leukaemia. One patient died from thrombosis of the portal vein. 38 patients were in complete remission 29 months (extremes: 14-44) after transplantation. 21 of 60 patients progressed or relapsed after transplantation, and 14 died. No death was attributed to graft failure, infection or haemorrhage. In conclusion, transplantation with peripheral blood stem cells is well tolerated, has a low toxicity rate, and can be used safely for patients with haematological malignancies.

Adolescent↗
PubMed2000

The diversity of antigen-specific antibodies in humans and in two xenochimeric SCID mouse models.

We applied two-dimensional gel electrophoresis (2-DE) to study the repertoire of tetanus toxoid (TT)-specific antibodies produced after TT immunization in healthy humans and in severe combined immunodeficient mice xenotransplanted with either human peripheral blood leukocytes (PBLe) or with human adult tonsil (hu-ton) pieces. Specific anti-TT antibodies, as well as total immunoglobulins (Ig), were purified by affinity chromatography on TT-Sepharose or Protein G-Sepharose, respectively. 2-DE unambiguously allowed us to differentiate between the specific humoral responses produced either by humans or by the two xenochimeric mouse models. Anti-TT antibodies produced by humans were polyclonal with a superimposed oligoclonality that was donor-dependent and that did not change upon time. By contrast, immunized hu-PBLe-SCID mice exhibited an evident clonal restriction of the Ig, which increased with time after boosting. Hu-ton-SCID mice showed a clonal diversity which was intermediate between those observed in humans and in hu-PBLe-SCID mice, and which was stable over time. In addition, information was gained by 2-DE, correlating with data obtained by enzyme-linked immunosorbent assay (ELISA), on the isotype composition of the anti-TT IgM response. Altogether, our results clearly demonstrated that the clonal diversity of monospecific antibodies can be appreciated by 2-DE, and that the largest diversity was found in humans when compared to that in xenochimeric models. In addition, mice implanted with pieces of lymphoid organs had the broadest anti-TT Ig diversity, an observation supporting the use of this model for the generation of antibodies with restricted specificity.

Animals↗
PubMed2000

Human adult tonsil xenotransplantation into SCID mice for studying human immune responses and B cell lymphomagenesis.

OBJECTIVE: To generate a human-mouse xenochimeric model where human cells remain clustered in the animal to optimize their interactions and recovery. MATERIALS AND METHODS: Severe combined immune deficient mice (SCID) were xenografted subcutaneously with human adult tonsil pieces (hu-ton-SCID mice). Such animals were: (a) compared with those receiving tonsil cells in suspension, and (b) immunized with de novo and recall antigens. RESULTS: Human tonsil pieces survived a long period of time in SCID mice, while polyclonal human T- and B-lymphocytes persisted in close vicinity within the implantation area; however, little or no graft-versus-host disease was detectable. Not surprisingly, local development of lymphoproliferative disease was often observed in animals receiving lymphoid implants from donors previously infected by the Epstein-Barr virus. One month after surgery, higher serum levels of human IgG were found in SCID mice transplanted with tonsil pieces (2x10(7) cells/animal) than in animals injected with 5x10(7) tonsil cells in suspension (1.9 vs. 0.3 mg/mL, p < 0.002). Importantly, the production of human IgG in hu-ton-SCID mice remained polyclonal for at least 6 months and was linked to the presence of cells within the implants. Immunization of hu-ton-SCID mice with hepatitis B core, a de novo antigen, did not produce a significant IgG immune response; however immunization with tetanus toxoid (TT), a thymus-dependent recall antigen, yielded high (> 700-fold increase in anti-TT IgG levels) and long-lasting (> 6 months) secondary immune responses. CONCLUSION: The hu-ton-SCID mouse xenochimeric model described in this report may improve our understanding of human lymphoid cell interactions, secondary immune responses, and lymphomagenesis.

Adult↗
PubMed2000

Preparation and analysis of fetal liver extracts.

The aim of this work is to describe the techniques that have been used for preparation and analysis of whole fetal liver extracts destined for in utero transplantation. Nine fetal livers between 12 and 17 weeks of gestation were prepared: cell counts and assessment of the hematopoietic cell viability were performed on cell suspensions. Hepatocytes represented 40 to 80% of the whole cell population. The remaining cells were constituted by hematopoietic cells (mainly erythroblasts), as well as by endothelial cells. The latter expressed CD34 on their surface, interfering with the assessment of CD34+ hematopoietic cells by flow cytometry. Direct visual morphologic control using alkaline phosphatase anti-alkaline phosphatase techniques was needed to differentiate hematopoietic from extra-hematopoietic CD34+ cells. Between 3.0 and 34.6 x 10(6) CD34+ viable hematopoietic cells were collected per fetal liver. Adequate differentiation of these cells into burst-forming units erythroid (BFU-E), colony-forming units granulocyte-macrophage (CFU-GM), and colony-forming units granulocyte erythroid macrophage megakaryocyte (CFU-GEMM) has been shown for each sample in clonogeneic cultures. In conclusion, fetal liver is a potential source of hematopoietic stem cells. Their numeration, based on the presence of CD34, is hampered by the expression of this antigen on other cells contained in the liver cell extract, in particular endothelial cells.

Antigens, CD34↗
PubMed2000

Hypocomplementemic panniculitis with paraprotein.

Two episodes of severe panniculitis accompanied by fever and an acute phase response were the main clinical features in a patient who had an unusual IgG kappa paraprotein. Both episodes responded promptly to steroids. Complement proteins of the early classical pathway were depleted in the patient's serum, and in vitro experiments indicated that the IgG kappa paraprotein activated complement directly. The association of recurrent panniculitis and paraproteinemia-hypocomplementemia has been described in 2 other patients. It should be recognized since its response to steroids is immediate.

Acute-Phase Reaction↗
PubMed1999

Monomeric complement-activating IgG paraproteins.

Three patients presented a unique syndrome of recurrent panniculitis with an IgGkappa paraprotein and depletion of the early components of the classical pathway of complement. The IgGkappa paraproteins were monomers with a normal structure, and with no evidence for aggregation, as assessed by electron microscopy and ultracentrifugation. Both heavy and light chains were of normal molecular size (SDS-PAGE), and the paraproteins were not heavily glycosylated. However, the paraproteins from all three patients had unusual features that included abnormal behavior on gel filtration chromatography and a heavy chain of high pI. When analyzed by fast protein liquid chromatography (Superdex 200), elution of the paraproteins was retarded, particularly when the ionic strength was increased. This retardation was partially reversed in 20% alcohol, and fully reversed in 6 M guanidine-HCl. Neither anti-C1 inhibitor nor anti-C1q autoantibodies were found in any of the patients' sera. However, the paraproteins bound to the globular heads of C1q at normal ionic strength. They activated C4 in normal human serum, but not in C1q-deficient serum. Activation led to the formation of C1s-C1 inhibitor complexes. Taken together, the data suggest that the unusual paraproteins have the capacity to bind C1q, which then leads to activation of C1. The ability of these paraproteins to activate C1, in spite of their being soluble monomers, is likely to be related to their unique physicochemical features.

Chromatography, Gel↗
PubMed1999

Micropurification and two-dimensional polyacrylamide gel electrophoresis of immunoglobulins for studying the clonal diversity of antigen-specific antibodies.

Presented here is a simplified method for purifying antigen-specific antibodies and analysing them by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). For this procedure, specific immunoglobulins (Ig) are bound to resin beads coated with antigen and, in the presence of sodium dodecyl sulphate and dithioerythritol, loaded directly onto isoelectric focusing strips for 2D-PAGE analysis. This technique bypasses antigen-specific Ig elution and concentration and therefore minimises antibody loss and simplifies sample preparation. Because of its high sensitivity, this technique permits clonal analysis of samples containing small quantities of Ig. We studied Ig anti-tetanus toxoid (TT) and IgG in sera from several sources. The resulting oligoclonal Ig anti-TT patterns contrasted with the polyclonal patterns of total IgG visualised after 2D-PAGE analysis of the respective serum samples.

Animals↗
PubMed1999

[Prevention of post-transfusion cytomegalovirus infection: recommendations for clinical practice].

Based on a review of the literature, guidelines for the clinical use of cytomegalovirus (CMV) seronegative cellular blood products are presented. The clinical fields of application include obstetrics and foetal, neonatal, and transplantation medicine. Seronegative blood products are indicated for the transfusion of pregnant women, foetuses, and neonates until the 3rd month of life. They are also indicated in patients undergoing transplantation, if the donor and the recipient are both seronegative for CMV. This indication is extended to all transplanted patients with unknown CMV serology, and for all patients after lung transplantation. Finally, deleucocyted blood products are not equivalent to CMV seronegative blood products, but their use can be an acceptable alternative in the event of shortage of CMV seronegative blood products.

Blood Component Transfusion↗
PubMed1999

Two-dimensional electrophoretic analysis of cryoproteins: a report of 335 samples.

Cryoproteins are defined as proteins precipitating at low temperature. Most frequently, the precipitate contains immunoglobulins (Igs), and are therefore called cryoglobulins. Three types of cryoglobulins have been described: type I contains a single monoclonal Ig, whereas type II is a mixture of a monoclonal Ig with polyclonal Igs, and type III is a mixture of polyclonal Igs of different isotypes, most frequently IgG and IgM. Type II and type III are also called mixed cryoglobulins. A new type of cryoglobulins, containing polyclonal IgG associated with a mixture of polyclonal and monoclonal IgM has recently been described after two-dimensional polyacrylamide gel electrophoresis (2-DE). This type of cryoglobulin has been called type II-III cryoglobulin. In this study, we report on 2-DE analysis of 335 cryoproteins from patients with heterogeneous clinical conditions. In 69 out of 335 samples (20.7%), 2-DE revealed patterns that were inadequate to characterize the cryoproteins. Out of 335 (79.3%) cryoproteins, 266 were identified according to their two-dimensional patterns: 265 samples contained Igs and were diagnosed as cryoglobulins, and one sample consisted of fibrinogen, and was identified as cryofibrinogen. Among the 265 cryoglobulins, types I, II, and III were observed in 9 (3.4%), 69 (26%), and 116 (43.8%) cases, respectively, whereas type II-III was detected in 71 (26.8%) cases. Eleven of the latter consisted of oligoclonal Igs (IgM in 10 cases, IgA in 1 case) mixed with traces of polyclonal IgG. These cryoproteins were tentatively named type II-IIIvariant cryoglobulins. Taken together, our result clearly show that 2-DE is a suitable technique to analyze cryoproteins.

Cryoglobulins↗
PubMed1999

Hepatitis virus-related and ethanol-induced chronic liver disease with or without cryoglobulins--is there a difference concerning clinical or laboratory manifestation?

Mixed cryoglobulinemia is frequent in southern Europe and attributed to hepatitis C infection. We analyzed prevalence and clinical symptoms of mixed cryoglobulinemia in our region among patients with chronic hepatitis C (n = 29) and B (n = 7) in comparison to alcoholic liver cirrhosis without evidence of hepatitis virus infection (n = 10). Cryoglobulinemia was found in 13/29 patients with hepatitis C (11 type III, one type I1-III and one type II), 2/7 with hepatitis B (one type II, one type III) and 4/10 with alcoholic liver cirrhosis (one type II, three type III). Patients with moderate active hepatitis had more type II than type III cryoglobulins. Concerning clinical symptoms, only sicca syndrome was more frequent in patients with hepatitis C. Rheumatoid factor (RF) and immune globulin M (IgM) levels were higher in hepatitis C than in the other groups. Renal disease was rare in all but not different between the groups. Mixed cryoglobulinemia in hepatitis C (and B) is most frequently of type III. Patients with hepatitis C had the same prevalence of cryoglobulins as patients with alcoholic liver cirrhosis. Cryoglobulins had no influence on clinical syndromes or organ damage.

Adolescent↗
PubMed1999

Haematological parameters of parvovirus B19 infection in 13 fetuses with hydrops foetalis.

Thirteen cases of fetal parvovirus B19 infection with hydrops foetalis are reported. Viral DNA was identified by polymerase chain reaction (PCR) of amniotic fluid sampled between the 19th and the 29th week of gestation. Haematological examination revealed severe anaemia in all cases and thrombocytopenia in 11/13 cases, which was severe in two cases. Six fetuses died in utero; two after intrauterine transfusion. Complete recovery was observed in seven fetuses; five cases were treated by intrauterine transfusions, and in two cases spontaneous recovery occurred. Upon follow-up, no case of congenital anaemia was observed.

Anemia↗
PubMed1999

The direct antiglobulin test: still a place for the tube technique?

OBJECTIVES: Antibodies of different immunoglobulin isotypes, or complement, may coat red blood cells in vivo. They are detected by the direct antiglobulin test (DAT), usually performed by the conventional tube technique. The purpose of this study was to compare the latter technique with the gel test. METHODS: Three hundred and ninety-eight consecutive samples, sent to our laboratory for direct antiglobulin testing, were analyzed with the tube technique and the gel test, using reagents from different manufacturers. Eighty-seven samples had been collected from newborns and 23 from fetuses. Results were expressed as positive or negative. RESULTS: In 162 out of 398 cases, the DAT was negative with both methods, whereas in 178 out of 398 cases, the DAT was positive with both techniques using polyspecific antibodies (observed agreement: 84.5%; kappa = 0.71). Discrepancies between the two methods were observed in 58 cases: 51 samples appeared as DAT positive using the tube method and negative with the gel test, whereas only 7 were positive exclusively with the gel test. Among the 178 samples that were positive with both techniques, 93 samples showed discordant results when evaluated with monospecific antisera (11 with anti-IgG and 82 with anti-C3d, respectively). The sensitivity of the DAT performed by the gel test, in comparison with the conventional tube technique, was 75.4% (95% confidence interval (CI): 69.4-80.8). 96. 8% (95% CI: 92.8-99.0), and 16.3% (95% CI: 9.8-24.9) with polyspecific, anti-IgG and anti-Cd3 reagents, respectively. CONCLUSIONS: The gel test appeared to be less sensitive than the conventional tube technique when utilized for DAT, particularly when C3d was present on red blood cells. These results emphasize that before implementing a new technique in the laboratory, comparison with existing techniques, using different reagents, is mandatory.

ABO Blood-Group System↗
PubMed1999

Microheterogeneity of serum glycoproteins in patients with chronic alcohol abuse compared with carbohydrate-deficient glycoprotein syndrome type I.

BACKGROUND: Chronic alcohol abuse alters the normal N-glycosylation of transferrin, producing the carbohydrate-deficient transferrin isoforms. This alteration could be similar to that present in patients with carbohydrate-deficient glycoprotein syndrome type 1 (CDG1). We thus compared the alterations of N-glycans present in patients with alcoholism and patients with CDG1. METHODS: The N-glycans of serum glycoproteins were compared in sera of patients with alcoholism, patients with CDG1, and controls by two-dimensional electrophoresis, neuraminidase, peptide:N-glycosidase F, and endoglycosidase F2 treatments. A specific antibody directed against the amino acid sequence surrounding the N-432 N-glycosylation site of transferrin was prepared (SZ-350 antibody). RESULTS: In patients with alcoholism, the abnormal transferrin and alpha(1)-antitrypsin isoforms were devoid of a variable number of entire N-glycan moieties and were identical with those present in CDG1. In the serum of patients with alcoholism, this finding was less pronounced than in CDG1. In contrast to CDG1, there was no decrease in clusterin or serum amyloid P in patients with alcoholism. The SZ-350 antibody recognized only transferrin isoforms with one or no N-glycan moieties. CONCLUSION: Antibodies directed against specific N-glycosylation sites of glycoproteins could be useful for developing more specific immunochemical tests for the diagnosis of chronic alcohol abuse.

Alcoholism↗