音猬因子的功能受体斑片在培养神经干细胞中的表达

目的　观察在培养的神经干细胞内是否有发育调控分子———音猬因子 (sonichedgehog)功能受体———斑片 (patched)表达。　方法　神经干细胞克隆在体外培养传代后 ,用patched的特异性引物对培养的神经干细胞进行RT PCR分析 ,PCR产物经克隆测序后 ,用地高辛标记克隆的探针 ,对神经干细胞进行原位杂交分析。　结果　神经干细胞克隆内大量的细胞均可表达sonichedgehog的功能受体patched ,patched阳性细胞间未见明显差别 ,克隆边缘与中央的patched分布也未见明显差别。　结论　sonichedgehog信号传导路可能在神经干细胞的增殖与分化过程中起重要作用。     

Polyetheretherketone--cytotoxicity and mutagenicity in vitro

The results of the incubation of polyetheretherketone (PEEK) fibre material with seven different genotype variants of salmonella bacterium showed with and without an external metabolic activation system (S9) with no mutagenic or cytotoxic activity of the test material. In the so-called "plate incorporation test" in which the PEEK raw material is finely cut and applied direct to the agar plate without the addition of solvent there was, as expected, no evidence of cytotoxic or mutagenic effects. In the HPRT test there was a significant increase in the number of mutants per dish, both after addition of N-acetylaminofluorene and N-methyl-N'-nitro-N-nitrosoguanidine (with and without an external metabolic activation system = +S9), but not after treatment of the cells with PEEK-DMSO-eluate. This means that the PEEK material under study did not release any substances that cause V79 cells to mutate. The investigation of the toxic reaction on the material under study revealed that the number of surviving colonies per 10(5) surviving cells lay within the range of or below the solvent control even in the presence of high PEEK concentrations (5.0 microg/ml). Therefore, in summary, the study produced no evidence of cell damage caused by PEEK.     

Effects of divicine, one of its degradation products and hydrogen peroxide on normal and pre-treated rat erythrocytes

The effects of divicine (DV), one of its degradation products ("blue DV"), and H2O2 on normal and pre-treated rat erythrocyte (RBC) reduced glutathione (GSH) content, spontaneous hemolysis at different tonicity levels, optical absorption spectrum of the hemolysate, as well as on their morphology were investigated. The influence of experimental conditions (temperature, pre- and post-treatment incubation period, presence and absence of glucose in the medium, aerobic and anaerobic conditions and levels of DV and "blue DV") were also studied. Only DV caused a marked decrease in GSH, which is regenerated when the DV level is below 4mM, and in the absence of glucose the regenerating capacity is abolished. DV and "blue DV" not only failed to induce hemolysis but they actually increased the cells' resistance to it; especially "blue DV", which probably lacked GSH-depressing effect. DV caused changes in the absorption spectrum of the hemolysate and to some extent in that of a purified hemoglobin solution, whereas "blue DV" and H2O2 did not. DV also produced profound and long-lasting morphologic changes in the RBC.     

Deciphering the molecular effects of non-ablative Er:YAG laser treatment in an in vitro model of the non-keratinized mucous membrane

Lasers in Medical Science -     

Mast cell desensitization to IgE fails to induce a parallel adenosine receptor desensitization

Desensitization induced by challenge of mast cells with antigen is specific for IgE-dependent signals. During the secretory process mast cells release adenosine, which can induce a desensitization of adenosine receptors. To determine whether adenosine receptors may de desensitized from a previous antigen challenge, mast cells were sensitized with anti-DNP IgE antibody, challenged with DNP-BSA antigen, returned to culture overnight, resensitized, and rechallenged. Previously challenged cells exhibited increased spontaneous -hexosaminidase release, but adenosine retained its ability to augment -hexosaminidase release. Adenosine enhanced A23187-stimulated release of -hexosaminidase in control and previously challenged cells. Leukotriene C₄ generation followed a similar pattern. Mastoparan, a direct G protein activator and mast cells secretogogue, produced a doubling of -hexosaminidase release in previously challenged cells. Results using other G protein activators were equivocal. Degranulation alone is insufficient to induce adenosine receptor hyposensitization. Whether the hyperresponsiveness to mastoparan is a consequence of uncoupling of IgE receptors from G proteins remains uncertain.     

Primary infiltrating signet ring carcinoma of the eyelids

A 61-year old man presented with a five-year history of a swelling initially developing in his right lower lid that progressed to involve the lateral canthal skin and eventually the upper lid and anterior orbit. He was discovered to have an infiltrating, poorly differentiated, mucin-producing carcinoma. Systemic work-up failed to disclose a visceral malignancy, and it was concluded that his tumor was primary in the lids, arising from an adnexal sweat gland. Three other reports in the literature also share almost identical clinical and pathologic features, in that all of the earlier reports dealt with middle-aged or elderly men who had diffusely indurated lids. Histopathologically, the tumor cells grow diffusely in a sclerotic stroma, and resemble the "histiocytoid" variant of metastatic breast carcinoma to the lids in women. Ultrastructural studies in our case point toward an apocrine origin, although earlier authors have favored an eccrine origin. Despite its indolent clinical course, the tumor is capable of producing regional and distant metastases on long-term follow-up. Complete local excision, possibly necessitating radical surgery, is probably the preferred method of treatment, but local radiotherapy may have a beneficial effect in retarding spread of the disease.     

The capsid protein-encoding sequence of foot-and-mouth disease virus O2Brescia

Summary Nucleotide sequences encoding the four capsid proteins of foot-and-mouth disease virus subtype O₂Brescia/1947 have been determined. These and the deduced amino acid sequences were compared with those of a subtype O₁ virus strain. The nucleotide sequences differed at 259 positions, causing only 35 amino acid changes. VP 4 and VP 2 differed by 2.4 and 1.8%, whereas VP 1, known as major viral antigen, and VP 3 differed by 8% and 5.5%, respectively. The differences occur mainly in protein domains not involved in the formation of -helices and -sheets, suggesting that the surfaces of both viruses are more variable than their scaffolds. The O₂Brescia sequence has been submitted to the GenBank data base and has the accession number M 55287.     

Hydrolysis of ochratoxin A by the microbial activity of digesta in the gastrointestinal tract of rats

This study established the influence of dietary neomycin sulphate on the rate of hydrolysis of ochratoxin A (OA) by digesta from the intestine, and its effect on the excretion of OA and its hydrolyzed metabolite, alpha ochratoxin (O), in the urine and feces of the rat. The first in vitro study demonstrated that digesta from the cecum and the large intestine were able to hydrolyze OA whereas digesta from the small intestine and stomach had very low hydrolytic activity against this substrate. Homogenates of the liver had no hydrolytic activity. The second in vivo study demonstrated that digesta from the large intestine and cecum of the neomycin treated rats was much less effective (P<0.001) in promoting the hydrolysis of OA than digesta from the control rats. Neomycin when added directly to the in vitro system, however, did not affect the rate at which OA was hydrolyzed. In a third study, OA was administered in vivo to control and neomycin-treated rats. Rats fed the neomycin containing diet compared to those fed the control diet had a higher concentration (P<0.005) of blood OA, and a greater cumulative excretion of OA plus O over the entire 5 day collection period in the feces (P<0.0001) and a corresponding decrease in the cumulative excretion of OA plus O in the urine (P<0.0001). Individually, there was a marked increase in cumulative fecal excretion of OA (P<0.05) and a corresponding decrease in excretion of O (P<0.05). Individual OA and O values in the urine tended to follow an opposite pattern to that seen in the feces but the differences were not significant (P<0.05). Overall, the results demonstrate that an antibiotic such as neomycin when added to the diet greatly reduces the rate of hydrolysis of OA by digesta from the lower sections of the gastrointestinal tract. Neomycin also alters the pattern of excretion of OA and O in the feces and possibly the urine in rats fed OA. These results suggest that intestinal microorganisms affect disposition of OA.     

脊髓栓系综合征研究近况

脊髓栓系综合征(Tethered cord syndrome，TCS)是指由于各种原因造成的脊髓纵向牵拉、圆锥低位、脊髓发生病理改变而引起的神经损害症候群，包括下肢感觉运动功能障碍、畸形、大小便功能障碍等。1953年首次临床报道，1981年由Yamada命名。