Culture of human vascular endothelial cells on a positively charged polystyrene surface, primaria: comparison with fibronectin-coated tissue culture grade polystyrene

Two culture surfaces, fibronectin-coated tissue culture grade polystyrene and a surface-modified polystyrene called Primaria (Falcon), were compared. The morphological (contact inhibition and cobblestone aspect), biological (production of von Willebrand factor and prostacyclin) and physiological (growth activity, non-thombogenicity and regeneration after mechanical injury) properties of human endothelial cells were studied. Adhesion and growth of endothelial cells at low and clonal density were identical on both substrates and the biological properties were preserved. Regeneration of injured endothelium was less easy to study on Primaria polystyrene because the extracellular matrix was damaged during the lesion process. Nevertheless, Primaria polystyrene can easily be substituted for fibronectin coating in growth experiments, especially at very low seeding density.     

Affiliation to mature B cell repertoire and positive selection can be separated in two distinct processes

Using an 'oligoclonal' model, we have previously shown that mice transgenic for a mu chain (H3) and deficient for kappa chain expression display a mature B cell repertoire largely dominated by the H3/lambda1 pair, while the four H3/lambda available combinations can be observed in the immature B cell compartment. This led us to propose the existence of a positive selection process. To test this hypothesis, we have introduced the SJL lambda locus coding for a defective lambda1 chain (lambda1(s)) that creates a dysfunctional Ig receptor complex during B cell differentiation. Our results show that the lambda1(s) defect impairs the development of mature B cells when the H3-mu transgene insert is present in the hemizygous state. This suggests that the Gly --> Val substitution present in the C(lambda)1(s) chain at position 155 is sufficient to abrogate the selection of the H3/lambda1 pair. Unexpectedly, when the H3-mu transgene array is present in a homozygous state in lambda1(s) mice but not in 'wild-type' lambda1 mice (lambda1(+)), a significant number of mature B cells expressing all H3/lambda combinations can be developed. These results indicate that the overriding H3/lambda1 dominance observed in lambda1(+) mice is due to a positive selection process and not to a negative selection of other H3/lambda combinations. They also show that the export of B cells to the periphery can be controlled by the expression of the mu chain.     

Allotypic restriction of the expression of MOPC460 idiotope after immunization with either anti-2,4-dinitrophenyl (DNP) or anti-idiotypic antibodies

The MOPC460 idiotype is expressed in mice with the IghCa allotypic haplotype after anti-2,4-dinitrophenyl (DNP) immunization. We have previously shown that two monoclonal syngeneic anti-idiotypic antibodies (IDM 92-13 and IDM 41-27) define two distinct idiotopes (the 460.92 and the 460.41) on the M460 idiotype. The current study demonstrates that only one idiotope (460.92) is recurrently expressed after antigen immunization in IghCa positive mice and also that, immunization against the monoclonal anti-idiotypic molecules induces the synthesis of 460.92 idiotope positive anti-DNP antibodies. However, the detection of such molecules is only possible when animals with the IghCa allotypic haplotype are immunized with the IDM 92-13 molecules. Immunization of mice with either of the two monoclonal anti-idiotypic antibodies never results in the synthesis 460.41 positive molecules. Therefore, whatever protocol of immunization used, the expression of 460.92 was allotypic restricted.     

Preferential VH/V lambda pairings occur in the available B cell repertoire of adult BALB/c mice.

To gain insights into the composition of the B cell repertoire, we have investigated VH gene family expression associated with individual light chains. For this purpose, we have examined the use of 12 VH gene families in a large collection of hybridomas expressing one of the four lambda light chains [lambda 1 (V1J1), lambda 2 (V2J2 and V x J2) and lambda 3 (V1J3)]. Our results show that the distribution of the VH families is very different from one lambda subtype to another. This suggests that a few substitutions between VL regions are sufficient to generate very different associated repertoires by strong selection mechanisms. Moreover, we assume that the global VH expression pattern is not random but rather composed of many preferential VH/VL associations.     

Inefficient protection of human TAP-deficient fibroblasts from autologous NK cell-mediated lysis by cytokines inducing HLA class I expression

We studied HLA class I expression and susceptibility to lysis of activated autologous NK cells in normal and TAP-deficient fibroblasts. These cells were cultured in the presence or absence of cytokines known to increase the surface expression of HLA class I molecules. All the cytokines tested (IFN-alpha, IFN-gamma, TNF-alpha and IFN-gamma + TNF-alpha) increased the expression of HLA class I molecules on fibroblasts after 48-h culture, but on TAP-deficient cells this expression remained very low as compared to that of normal cells. In the presence of IFN-alpha, IFN-gamma or IFN-gamma + TNF-alpha, normal target cells became resistant to lysis by autologous NK cells, whereas this effect was much less pronounced in the case of TAP-deficient fibroblasts. Addition of an anti-HLA class I mAb to fibroblasts treated with cytokines increased lysis of normal but not of TAP-deficient cells. These results suggest that activated TAP-deficient NK cells are strongly cytotoxic to normal autologous cells and that these cells cannot be efficiently protected by cytokines inducing HLA class I expression. Thus, in human TAP deficiency, activated NK cells may contribute to the progressive lung degradation which characterizes the clinical course of these patients.     

Antenatal differentiation of the human intervertebral disc

Summary To study the antenatal differentiation of the human intervertebral disc, the columns of forty eight embryos and fetuses were examined histologically. The primitive disc is composed of two structures: the notochord which shows a progressive expansion into the disc, and the fibrocartilaginous perinotochordal disc. No histological sign of interaction between notochordal and perinotochordal cells, which may explain the notochordal expansion into the discs, was seen. On the other hand, the notochordal intervention in the cartilaginous differentiation of the inner zone is probable.

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Différenciation anténatale du disque intervertébral humain

Résumé Cette étude de la différenciation anténatale du disque intervertébral humain repose sur l'examen de coupes histologiques de quarante huit colonnes vertébrales d'embryons et de foetus. Le disque primitif est composé de deux structures : la notochorde, qui présente une expansion progressive de son diamètre au sein du disque, et le disque périnotochordal, d'abord mésenchymateux puis fibrocartilagineux. Il n'a pas été mis en évidence de signe histologique témoignant d'une interaction entre les cellules notochordales et les cellules périnotochordales qui puisse expliquer l'expansion de la notochorde au sein des disques. Le rôle de la notochorde dans la différenciation cartilagineuse de la zone centrale est par contre probable.

     

温血心停跳液与冷晶体心停跳液对狗心率变异性的影响

为探讨体外循环（ＣＰＢ）导致心脏植物神经系统（ＣＡＳ）损伤的机理,了解温血心停跳液能否防止ＣＰＢ后心率变异性（ＨＲＶ）的降低,采用对照方法观察了温血心停跳液与冷晶体心停跳液对狗ＨＲＶ的影响。结果显示：ＣＰＢ后温血心停跳液组（ＷＢ组）和冷晶体心停跳液组（ＣＣ组）的全频谱（ＴＰ）、低频（ＬＦ）和高频（ＨＦ）均较术前明显降低（Ｐ＜０．０５）,而且ＣＣ组比ＷＢ组降低更明显（Ｐ＜０．０５）,但ＬＦ／ＨＦ在组内及组间均无明显变化（Ｐ＞０．０５）。ＣＰＢ后２４小时平均心率（ＭＨＲ）明显增加（Ｐ＜０．０５）,且ＣＣ组高于ＷＢ组（Ｐ＜０．０５）。本研究表明：采用温血心停跳液或冷晶体心停跳液的ＣＰＢ不会干扰ＣＡＳ平衡,但均能使ＨＲＶ降低,温血心停跳液不能防止ＨＲＶ损害。     

Antithrombotic effects of (n-3) polyunsaturated fatty acids in rat models of arterial and venous thrombosis

The antithrombotic effects of dietary lipids were investigated in rat models of arterial and venous thrombosis. In the arterial model, thrombus formation was evaluated by determination of the occlusion time and the deposition of 111In-labeled platelets and 125I-labeled fibrinogen in a collagen-coated glass capillary inserted into an arterio-arterial shunt. Venous thrombosis was evaluated by measurement of the thrombus weight after administration of thromboplastin as a source of tissue factor and establishment of stasis in the vena cava. Diets were supplemented with saturated (SAT group) or (n-3) fatty acids, the latter being added either as MaxEPA oil (MaxEPA group), or as docosahexaenoic (DHA group) or eicosapentaenoic (EPA group) ethyl ester. Only the MaxEPA group displayed a prolonged occlusion time as compared with all other groups. Platelet accumulation, similar in the MaxEPA, EPA and DHA groups (13.3, 16.7 and 17.7 x 10(6) platelets/shunt, respectively), was significantly higher in the SAT group (25.3 x 10(6) platelets/shunt), while accumulation of fibrinogen-fibrin was similar whatever the group. There was a trend towards a lower venous thrombus weight in MaxEPA fed rats relative to those fed other diets. Our data indicate that the MaxEPA diet had antithrombotic effects in arterial and to a lesser extent venous thrombosis models, best attributed to its multiple targeting of platelets and coagulation.     

Headache and family history

In two headache questionnaire surveys we inquired about the occurrence of headache in the mothers, fathers, siblings and children of the respondents. In total, 633 people completed valid questionnaires, 260 in the first survey and 373 in the second. The hypothesis was that familial headache occurrence would be positively associated with headache frequency. In each survey, the regression of headache frequency on the number of parents having headache was highly significant. Neither sex nor the sibling and children variables were significant predictors. In the cross-tabulations of the parental occurrence of headache with headache frequency we saw a clear "break-point" between the "no headache" and the headache frequency categories studied. For the final analyses the dichotomy "headache/no headache" was related in fourfold tables to headache occurrence in the father and the mother separately, and to the number of headache parents. The positive associations were not simply due to the large number of migraine cases since they remained after removing the migraineurs.