Changes in thymic export of L-selectin+ γδ and αβ T cells during fetal and postnatal development

We have used the technique of in situ intrathymic injection of fluorescein isothiocyanate to examine L-selectin expression on γδ and αβ T cells immediately after emigrating from the thymus of fetal and postnatal animals. We found that the percentage of L-selectin⁺ thymocytes exported per day decreased by half after birth and that the export of T cells from the thymus does not rely on expression of the peripheral lymph node homing receptor, L-selectin. Analysis of L-selectin on emigrant and mature T cell subsets revealed a remarkable heterogeneity of expression, both in terms of the numbers of cells expressing this molecule as well as the level of expression. γδ T cells, reportedly not having a propensity for homing to lymph nodes, not only contained the highest proportion of L-selectin⁺ cells, but also expressed far more of this molecule than either CD4⁺CD8^? or CD4^?CD8⁺ αβ T cells. Furthermore, those emigrant T cells expressing L-selectin are somewhat immature in their expression of this molecule. Subsequent maturation resulted in up-regulation of L-selectin on mature peripheral blood T cells, maturation that was clearly independent of extrinsic antigen. This antigen-independent post-thymic maturation appeared to occur as part of the normal progression from immature thymocyte to mature peripheral T cell in both fetal and postnatal animals.     

Chemical Characterization of Macrophage Cytotoxicity Factor,Macrophage Migration Inhibitory Factor,T-Helper Cell-Replacing Factor and Colony-Stimulating Factor from Culture Supernatants of Concanavalin A-Stimulated Murine Spleen Cells

Supernatants from Concanavalin A-stimulated murine spleen cells were subjected to hydrophobic interaction chromatography on phenyl-Sepharose. Macrophage cytotoxicity factor (MCF), macrophage migration inhibitory factor (MIF), T-helper cell-replacing factor (TRF) and colony-stimulating factor (CSF) were bound at high ionic strength and were released stepwise at low ionic strength. CSF thus could be separated from MCF, MIF and TRF and the bulk of other proteins. Chromatography of pools containing MCF, MIF and TRF on Sephadex did not lead to a separation of the three activities which were all found in a molecular weight range of 25.000-55.000. Isoelectric focusing of these pools in pH range from 4 to 9 gave two peaks for MCF at pH 8.2 and 7.2, whereas MIF activity focused from pH 4.5 to 5.5. TRF activity was found in a single sharp peak at pH 5.3. The results demonstrate that the four biological activities can be distinguished on a chemical basis and are accessible for purification and chemical characterization.     

Intramesenteric fetal rat small-bowel transplantation

Previous studies have shown that transplantation of fetal rat small bowel into the greater omentum of adult recipient animals can be successfully carried out. However, the surface area of the omentum limits the length of implantable fetal small bowel. Furthermore, clinical experience has shown that due to adhesions, the greater omentum is no longer suitable as an implantation site after multiple laparotomies, which often precede a short-bowel syndrome. We wanted to examine whether recipient mesentery is a further possible site of fetal gut implantation. Four weeks after transplantation of the fetal graft into the mesentery of adult rats, mature intestine was found in 80% of the animals. Macroscopically, the developed transplants looked like bowel duplications"; light-microscopic examinations documented their morphologic integrity.     

胎鼠胃上皮细胞增殖和分化的电镜和免疫组化观察

用电镜和免疫组化的方法观察了15～16天胎龄的胚胎大鼠胃上皮组织在体外培养过程中增殖及分化的情况。结果表明未分化的上皮细胞在培养过程中大量增殖．并分化出粘液细胞、壁细胞等功能细胞。并初步表明氢化可的松可以促进这一分化过程的进行。实验为在体外研究胃粘膜未分化的干细胞的增殖和分化这一重要生理活动建立了方法,所得结果初步提示皮质激素可能会影响胃粘膜干细胞的增殖分化。     

Prognostic factors in fetal hydronephrosis: a multivariate analysis

With the increasing use of obstetric echography fetal hydronephrosis has been reported more frequently. The purpose of this study was to identify prognostic factors associated with adverse outcome, such as renal failure and death, in fetal hydronephrosis. One hundred and forty-eight children with fetal hydronephrosis were admitted, submitted to a systematic protocol, and prospectively followed. Prognostic factors associated with fetal echography and clinical and laboratory findings on admission were studied. The median follow-up was 39 months. The analysis was conducted in two steps. In a univariate analysis, variables associated with adverse outcome were identified by the Kaplan-Meier method. The variables that were significantly associated with adverse outcome were then included in a multivariate analysis. This analysis, using the multivariate Cox’s model, was performed to identify variables that were independently associated with a worse prognosis. Only variables that remained independently associated with adverse outcome were included in the final model. After final adjustment by Cox’s multivariate model, three variables were identified as independent predictors of adverse outcome: oligohydramnios, prematurity, and glomerular filtration rate lower than 20 ml/min. Thus, in the presence of oligohydramnios, prematurity, and abnormal renal function, the medical team must plan appropriate follow-up for infants at health centers prepared to investigate and treat uropathies in newborns. Received: 24 August 1998 / Revised: 7 December 1998 / Accepted: 11 December 1998     

Neurovascular developmental interaction: a specific form of vascular maldevelopment in the malformed brain

The process of the development of the intracranial vessels was studied by means of immunohistochemical analysis of factor VIII in normal and exencephalic chick fetuses. The results revealed that the development of blood vessels in exencephalic brain was far advanced beyond the norm, with intense immunoreactivity to factor VIII on postincubation day 16 exceeding that on day 21 in normal controls. Compared with results regarding the direction of the overgrowth in the neuronal maturation process in the previous study using the chick exencephaly model, the findings of overmatured blood vessels were compatible with NSE- and somatostatin-positive elements that appeared especially in the overgrowth foci. The results of the present study suggested the pathogenic development of the area cerebrovasculosa in the neural placode as a phenomenon consequent upon hypervascularization in response to neuronal overgrowth, as seen in human cases of exencephaly or anencephaly. We emphasize the significance of this specific phenomenon in the development of the fetal central nervous system, namely neurovascular developmental interaction.     

Definition of inseparably fused ventricular myocardium in thoracopagus: Fetal echocardiographic utility and pathologic refinement

Summary Correlative echocardiographic and pathological findings in a thoracopagus with conjoined hearts are reported. One twin had tricuspid atresia with discordant atrioventricular connections and concordant ventriculoarterial connections. The morphologic right ventricle was hypoplastic and there was a large muscular ventricular septal defect. The other twin had hypoplasia of the mitral valve anulus and left ventricle with double-outlet right ventricle and pulmonary valve atresia. The tricuspid valve was severely insufficient in part because of a large orifice and redundant, elongated leaflets with abnormal chordal attachments. The left ventricles of these two twins shared a perforated common free wall with at least two large defects allowing mixing of the circulations at that level. Not all anatomic details were established conclusively by fetal echocardiography; however, sufficient diagnostic information was obtained to support a decision not to aggressively resuscitate these twins after elective cesarean delivery at 31 weeks' gestation.     

Fetal Krabbe leukodystrophy

Summary Two new cases of Krabbe disease were diagnosed prenatally in a family with two previous affected children. The activity of galactosylceramide--galactosidase was virtually absent in cultured amniotic cells.The prenatal diagnosis was confirmed enzymatically in cultured fibroblasts, brain, and visceral organs.Light and electron microscopy studies in both fetuses, 20 and 23 weeks of gestational age respectively, revealed the presence of typical globoid cells in the white matter of the spinal cord. Specific inclusions were also found in the brain stem and in peripheral nerves of the second fetus.A comparison with other Krabbe disease fetuses described in the literature contributes to the consensus that abnormal morphological findings can be expected in particular in the most actively myelinating areas of the nervous system.Although most of the cells containing the specific melusions are probably non-glial in nature, some of them could represent myelination glia.This work was supported by the FGWO (grants nos. 3.0033.77 and 3.0012.77), by the FRSM (grant no. 3.4542.79), and by the Baron Charles Bracht Foundation     

胎儿生长的数学模型

根据孕 16～ 2 8周胎儿双顶径、头围、腹围及股骨长等的超声测量值拟合 Rossavik数学模型 [P=c(t) k+ s( t) ]建立胎儿个体生长曲线。结果显示 ,2 0例正常单胎的超声参数与 Rossavik模型的拟合效果好 ,孕 2 8～ 41周胎儿各项参数的模型预测值与实测值比较均无显著差异     

白细胞介素2激活脐血单个核细胞体外抗肿瘤活性的实验研究

为探讨白细胞介素２（ＩＬ－２）激活脐血单个核细胞（ＡＣＢ）对白血病细胞株ＨＬ－６０和Ｋ５６２细胞的杀伤作用以及脐血被激活后能否保持其造血祖细胞生成活性（ＰＣＡ），采用３Ｈ－胸腺嘧啶核苷前标记释放法和半固体培养等方法对其进行了研究。结果：ＩＬ－２激活的脐血细胞具有明显的抗肿瘤活性，且不影响其ＰＣＡ。ＩＬ－２激活脐血细胞的最适条件为：（１）细胞浓度为１×１０６ｍｌ；（２）ＩＬ－２浓度为１０００Ｕ／ｍｌ；（３）效靶比为１００１；（４）体外培养７２小时。脐血经ＩＬ－２激活后免疫表型发生明显变化，产生肿瘤坏死因子（ＴＮＦα）及白细胞介素６（ＩＬ－６），且生成大颗粒淋巴细胞（ＬＧＬ）。ＬＧＬ与Ｋ５６２细胞作用后，后者呈凋亡特征。研究结果为临床应用ＡＣＢ治疗白血病提供了实验依据。