鸡后根神经节多巴胺细胞在体及体外培养中的免疫细胞化学观察

应用免疫细胞化学PAP法,研究了鸡胚和雏鸡后根神经节细胞内多巴胺递质的表现与胚胎发育过程中的变化,并在细胞培养条件下研究了周围靶组织——皮肤对后根节细胞胚胎发育的影响。鸡后根节细胞内多巴胺的免疫反应最先出现于E_(10),只占后根节细胞的0.8%,E_(18)时达5.6%,出壳后雏鸡为8.6%。在鸡后根节内,多巴胺免疫反应阳性细胞主要为较大的A类细胞,和极少较小的B类细胞。免疫反应阳性的周围神经末梢位于皮肤和交感干内。当取自E_9的鸡胚后根节细胞经7天培养后,部分神经细胞出现多巴胺免疫反应阳性;而取自E_6的鸡胚后根节细胞虽经10天培养后仍为免疫反应阴性;然而,将取自E_6后根节细胞与皮肤组织联合培养10天后,少量神经细胞及轴突出现多巴胺免疫阳性反应。作者认为:鸡后根节多巴胺细胞在胚胎时期的发育有赖于周围靶组织的作用。     

Interleukin-1β and anaphylatoxins exert a synergistic effect on NGF expression by astrocytes

C3a and C5a anaphylatoxins are proinflammatory polypeptides released during complement activation. They exert their biological activities through interaction with two G protein-coupled receptors named C3aR and C5aR, respectively. In the brain, these receptors are expressed on glial cells, and some recent data have suggested that anaphylatoxins could mediate neuroprotection. In this study, we used RT-PCR and ribonuclease protection assays (RPA) to investigate the role of anaphylatoxins on neurotrophin expression by the human glioblastoma cell line T98G and by rat astrocytes. Our data show that for both cell types, anaphylatoxins upregulate expression of NGF mRNA. This response depended on a G protein-coupled pathway since pre-treatment of cells with pertussis toxin (PTX) completely blocked NGF mRNA increases. This effect was anaphylatoxin-specific since pre-incubation with anti-C3a or anti-C5aR antibodies abolished the effects of C3a and C5a, respectively. The regulation of NGF mRNA by anaphylatoxins was not accompanied by translation into protein expression, but there was a significant synergic effect of anaphylatoxins/IL-1b costimulation. Our demonstration of involvement of anaphylatoxins in the NGF release process by astrocytes suggests that C3a and C5a could modulate neuronal survival in the CNS.     

Effect of intensive swimming training on lung volumes, airway resistances and on the maximal expiratory flow-volume relationship in prepubertal girls

The aim of the present study was to analyse the effect of 1 year of intensive swimming training on lung volumes, airway resistance and on the flow-volume relationship in prepubertal girls. Five girls [9.3 (0.5) years old] performing vigorous swimming training for 12?h a week were compared with a control group of 11 girls [9.3 (0.5) years old] who participated in various sport activities for 2 h per week. Static lung volumes, maximal expiratory flows (MEF) at 75, 50 and 25% of vital capacity, 1-s forced expiratory volume (FEV_1.0) and airway resistance (R _aw) were measured by means of conventional body plethysmograph techniques. Prior to the training period there were no significant differences between the two groups for any of the parameters studied. Moreover, for both groups, all parameters were within the normal range for children of the corresponding age. After 1 year of training, vital capacity (VC), total lung capacity (TLC) and functional residual capacity (FRC) were larger (P<0.05) in the girl swimmers than in the control group, while physical development in terms of height and weight was similar. FEV_1.0 (P<0.01), MEF₂₅, MEF₅₀ (P<0.05) and MEF₇₅ as well as the ratio MEF₅₀ / TLC (P<0.05) had increased in the girl swimmers but were unchanged in the control group. R _aw tended to be lower in the girl swimmers and higher in the control group. The results indicate that intensive swimming training prepuberty enhances static and dynamic lung volumes and improves the conductive properties of both the large and the small airways. As to the causative mechanism, it can be speculated that at prepuberty intensive swimming training promotes isotropic lung growth by harmonizing the development of the airways and of alveolar lung spaces.     

Isolations of Corynebacterium kroppenstedtii from a breast abscess

The recently described species Corynebacterium kroppenstedtii was isolated from a breast abscess in a 38-year-old woman on two occasions. We discuss the pathogenic role of this bacteria and the methods used for its isolation.     

Malaria infection during childbirth and in newborns in Bécédi (Ivory Coast)]

Authors studied the parasitological and serological status of 108 new-born children from 102 deliveries during the 2nd term of 1987 at the Bécédi Maternity Hospital in Ivory Coast. The parasitism frequency of different studied bloods (mother, cord, delivery) is varying from 8 to 14%, antibodies have been found in 81 to 83% cases. The parity has an effect on the placental lesions frequency but not on the parasitism frequency. Children born with a pathogenic placenta have a lower birth weight. The retrospective study of 11,070 deliveries from last years shows that birth weight are lower while the two first pregnancies.     

Hemorrhagic forms of Rift Valley fever in Mauritania

During and after a Rift Valley fever (RVF) epidemic in Southern Mauritania, we collected 600 clinical observations. 348 were confirmed to be RVF cases. Among the 5 clinical forms we observed, some are benign but others, especially those with hemorrhagic signs are serious. We observed 48 icterohemorrhagic forms with 25 deaths. An icterus was associated with hemorrhagic signs, varying from gingivorrhagia to abundant bleeding. Biological hepato-nephritis was always present in major hemorrhagic forms. Fulminant forms, spectacular and characteristic are excellent markers for epidemiological studies in the field.     

Phosphatidylserine externalization in human sperm induced by calcium ionophore A23187: relationship with apoptosis, membrane scrambling and the acrosome reaction

BACKGROUND: Translocation of phosphatidylserine (PS) from the inner to the outer leaflet of the plasma membrane is a modification of the lipid architecture occurring in sperm. This is one of the earliest signs of apoptosis that can be monitored by the calcium-dependent binding of annexin V. METHODS AND RESULTS: Flow cytometric analysis of annexin V binding was performed. Calcium ionophore A23187 led to a significant increase in the proportion of living sperm with PS exposure: 7.3 3.2% of cells in the untreated ejaculate versus 47.5 5.6% of cells after 1 h of incubation with A23187. Conversely, diminution of mitochondrial membrane potential [DiOC6(3)/propidium iodide (PI) assay], caspase activation [fluorescein isothiocyanate (FITC)-Val-Ala-Asp-fluoromethylketone (VAD-FMK)/PI assay], increased plasma membrane permeability (Yo-Pro-1/PI assay) and increased DNA fragmentation [TdT (terminal deoxynucleotidyl transferase)-mediated dUDP nick-end labelling assay], which are among the main signs of apoptosis, were not observed in sperm, even after 4 h of incubation with A23187. However, A23187 significantly increased the proportion of sperm with plasma membrane scrambling and with a reacted acrosome, as detected with the merocyanine 540 probe (M540) and the monoclonal anti-human CD46-PE antibody respectively. CONCLUSIONS: Our results suggest that PS exposure in human sperm, as induced by A23187, is mainly related to the acrosome reaction rather than to apoptosis.     

Diblock Copolymers Based on 1,4‐Dioxan‐2‐one and ε‐Caprolactone: Characterization and Thermal Properties

Summary: Various poly(ε‐caprolactone‐block‐1,4‐dioxan‐2‐one) (P(CL‐block‐PDX)) block copolymers were prepared according to the living/controlled ring‐opening polymerization (ROP) of 1,4‐dioxan‐2‐one (PDX) as initiated by in situ generated ω‐aluminium alkoxides poly(ε‐caprolactone) (PCL) chains in toluene at 25 °C. 1 ¹H NMR, PCS and TEM measurements have attested for the formation of colloids attributed to a growing PPDX core surrounded by a solvating PCL shell during the polymerization of PDX promoted by ω‐Al alkoxide PCL chains in toluene. The thermal behavior of the P(CL‐block‐PDX) copolymers was studied by DSC; showing two distinct melting temperatures (as well as two glass transition temperatures) similar to those of the respective homopolyesters. Finally, the thermal degradation of the P(CL‐block‐PDX) block copolymers was investigated by TGA simultaneously coupled to a FT‐IR spectrometer and a mass spectrometer for evolved gas analysis (EGA). The degradation occurred in two consecutive steps involving a first unzipping depolymerization of the PPDX blocks followed by the degradation of the PCL blocks via both ester pyrolysis and unzipping reactions.

TEM observation of P(CL‐block‐PDX) block copolyesters ( = 11 600 and = 22 100) as formed by vaporization starting from a diluted suspension in toluene/TCE mixture solvent (50/50 v/v).