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C Bensimon

Publications and source records attributed to C Bensimon.

10 recordsLinked to original sources
PubMed2003

A new 1-hydroxy-2,6-pyrazinedione associated with hypovirulent isolates of Sclerotinia minor.

A new 1-hydroxy-2,6-pyrazinedione, sclerominol (1), was isolated from cultures of hypovirulent isolates of Sclerotinia minor, a fungal plant pathogen associated with lettuce drop and other plant diseases. This compound was characterized by NMR, mass spectrometry, and X-ray crystallography. One other 1-hydroxy-2,6-pyrazinedione, flutimide, has been reported. Flutimide has activity as an inhibitor of influenza virus endonuclease, and therefore, sclerominol was evaluated for related biological activity. Sclerominol (1) displayed some activity against cancer cell lines but little activity against three influenza virus strains. The role of 1 in the physiology of hypovirulent isolates of S. minor has not been determined, but 1 has also been recovered from debilitated isolates of S. sclerotiorum.

Antineoplastic Agents↗
PubMed1996

Pancreatic transplantation in experimental non-insulin-dependent diabetic rats.

The effect of pancreatic transplantation on noninsulin -dependent diabetes mellitus (NIDDM) had not been evaluated in animal models. We assessed its impact by the insulin-glucose clamp study in experimental diabetic rats. NIDDM was induced in Lewis female rats by streptozocin at the age of 5 days (n5-STZ). To determine its effect on insulin sensitivity, we measured the glucose turnover rate and performed euglycemic hyperinsulinemic clamp studies, evaluating hepatic glucose production (HGP) and glucose uptake. This assessment was conducted on 5 groups of 6 female Lewis rats: 2 groups n5-STZ tested at the age of 10 and 14 weeks, respectively; 2 normal age-matched groups; and a fifth group (n5-STZ) transplanted at 10 weeks of age and tested at 14 weeks. Heterotopic pancreaticoduodenal transplantation was performed, using an end-to-side anastomosis between the donor celiac artery and portal vein to the recipient infrarenal aorta and vena cava, respectively. Pancreatic drainage was achieved by an end-to-side duodenojejunostomy. At 10 weeks of age, diabetic n5-STZ rats showed decreased body weight, hyperglycemia, moderate insulinopenia, a significantly higher basal HGP as compared with normal controls (28.5 +/- 10 vs. 10.7 +/- 4 mg/kg/minute, P<0.05), and ineffective suppression of the HGP by the insulin infusion. Glycemia, body weight, and basal HGP were normalized in the transplanted group and were statistically similar to age-matched normal controls. HGP was totally suppressed by the insulin infusion. However, the blood insulin level remained significantly higher than in the normal groups (P<0.05). We conclude that n5-STZ is a reliable model of NIDDM and that pancreatic transplantation, without immunosuppressive drugs in this isogenic line, corrects all tested parameters of glucose homeostasis and improves insulin sensitivity.

Animals↗
PubMed1996

[Is there a role for pancreas transplantation in the treatment of type II diabetes mellitus? Experimental study].

There is no experimental basis for transplantation of the pancreas in patients with non-insulin-dependent diabetes mellitus. We compared results in normal and grafted non-insulino-dependent Lewis rats. A heterotopic pancreatico-duodenal graft was implanted with end-to-side anastomosis of the coeliac artery and the portal vein of the donner on the infrarenal aorta and inferior vena cava of the recipient. The diabetic rats showed weight loss, high blood glucose levels (3.30 +/- 1.25 milligrams), moderate insulinopenia and significantly elevated liver production of glucose. Glycaemia, weight and liver production of glucose were the same as those in the group of normal animals. We concluded that transplantation of the pancreas in an isogenic model without immunosuppression can correct glucose levels and insulino-resistance. It could be suggested in man.

Animals↗
PubMed1994

Human lupus anti-DNA autoantibodies undergo essentially primary V kappa gene rearrangements.

We have recently characterized the heavy chain variable region (VH) genes expressed by a panel of human anti-DNA antibodies derived from four patients with systemic lupus erythematosus and expressing an idiotypic marker representative of a subset of pathogenic autoantibodies. Here, we have cloned and sequenced the kappa chain variable region genes (V kappa) of the clones whose VH genes had been previously analysed. All the V kappa genes utilized map to the 280 kb portion of the 3' end of the locus, suggesting that they represent essentially the products of primary rearrangements. This proximal clustering of the V kappa genes used contrasts with the broad distribution of immunization-induced human antibody V kappa genes over 1400 kb of the locus. In addition, lupus autoantibodies show no tendency to express the downstream junctional (J kappa) exons--another indication of infrequent secondary variable gene assembly. Since successive rearrangements may extinguish high-affinity recognition of self antigens, we propose that this bias in V kappa and J kappa expression reflects a low rate of secondary light chain rearrangements among lupus autoantibodies. We also postulate that the corrective mechanism capable of editing potentially aggressive, self-reactive antibodies in these patients may be deficient--a deficit that could be genetically determined and/or somatically acquired.

Amino Acid Sequence↗
PubMed1989

Two distinct affinity binding sites for IL-1 on human cell lines.

We used two human cell lines, NK-like YT-C3 and an EBV-containing B cell line, 3B6, as models to study the receptor(s) for IL-1. Two distinct types of saturable binding sites were found on both cell lines at 37 degrees C. Between 1 pM and 100 pM of 125I-IL-1-alpha concentration, saturable binding sites were detected on the YT-C3 cells with a K of 4 x 10(-11) M. The K found for the IL-1-alpha binding sites on 3B6 cells was 7.5 x 10(-11) M. An additional binding curve was detected above 100 pM on YT-C3 cells with a K of 7 x 10(-9) M and on 3B6 cells with a K of 5 x 10(-9) M. Scatchard plot analysis revealed 600 sites/cell with high affinity binding and 7000 sites/cell with low affinity for YT-C3 cells and 300 sites/cell with high affinity binding and 6000 sites/cell with low affinity for 3B6 cells. At 37 degrees C, the internalization of 125I-labeled IL-1 occurred via both high and low affinity IL-1R on both YT-C3 and 3B6 cells, whereas the rates of internalization for high affinity binding sites on YT-C3 cells were predominant in comparison to that of low affinity binding sites. In chemical cross-linking studies of 125I-IL-1-alpha to 3B6 and YT-C3 cells, two protein bands were immunoprecipitated with Mr around 85 to 90 kDa leading to an estimation of the Mr of the IL-1R around 68 to 72 kDa. In similar experiments, the Mr found for the IL-1R expressed on the murine T cell line EL4 was slightly higher (around 80 kDa). Whether these distinct affinity binding sites are shared by a single molecule or by various chains remains to be elucidated.

Adolescent↗
PubMed1989

A monoclonal antibody recognizing 68- to 75-kilodalton protein(s) associated with the human IL-1 receptor.

We produced an IgM mAb termed 4.9 against an EBV-containing lymphoblastoid cell line, termed 3B6. This mAb reacted with both various B and T cell lines such as HSB2 cells, with an NK-like cell line YT-C3 cells, and with human fibroblast MCR-5 cells. It also reacted with normal resting peripheral B lymphocytes, monocytes, and anti-CD2- or anti-CD3-activated T lymphocytes. The 4.9 mAb immunoprecipitated two bands estimated to be of Mr 68 and 75 kDa from iodinated 3B6 cells. The 4.9 mAb inhibited the proliferation of peripheral T lymphocytes induced either by anti-CD3 mAb or anti-CD2 mAb. The 4.9 mAb inhibited also the proliferation of murine thymocytes both in the presence of PHA and IL-1 and the proliferation of human fibroblasts in the presence of IL-1. Radiolabeled IL-1 binding on 3B6 cells revealed two types of IL-1 binding sites with high and low affinity for IL-1 (300 sites/cell with a Kd of 6 x 10(-11)M and 6000 sites/cell with a Kd of 3 x 10(-9)M). On both 3B6 and YT-C3 cells, mAb 4.9 inhibited specifically the binding of 125I-labeled rIL-1, alpha or beta, whereas the irrelevant IgM mAb did not. Conversely, rIL-1, alpha or beta, could inhibit specifically the binding of radioiodinated 4.9 mAb to 3B6 or YT-C3 cells, whereas rIL-2, rIFN, or the irrelevant IgM mAb were ineffective. 125I-4.9 mAb bound 3B6 cells with an association constant (Ka) of 2 x 10(8)/M and demonstrated 6000 binding sites/cell. We thus conclude that mAb 4.9 recognizes a protein complex (68 to 75 kDa) closely associated with the IL-1R.

Adult↗
PubMed1983

Syndesmo-odontoid joint and calcium pyrophosphate dihydrate deposition disease (CPPD).

Twenty-seven patients with definite or probable CPPS have been investigated with systematic frontal and lateral tomograms of the cervicooccipital region. In 12 cases there were calcifications of the syndesmo-odontoid region. These calcifications are of two different types: linear calcifications (5 cases) and mottled calcifications (7 cases). The anatomic location of these calcifications is the transverse ligament or other structures of the syndesmo-odontoid joint. Although this type of calcification has already been described in other rheumatic diseases, it must lead to search for CPPD in the usual locations.

Aged↗