1141610241Altered expression of HuR, an mRNA stabilizing protein, mediates aberrant Placenta Growth Factor (PlGF) expression in preeclampsia

Background:  Control of mRNA stability is an essential regulatory process in eukaryotic gene expression. HuR, a 3'UTR mRNA binding protein, can protect AU-rich mRNA from degradation in response to stresses. PlGF, an angiogenic growth factor, contains two consensus AU-rich sites suggesting that under normal conditions HuR may protect PlGF mRNA from degradation. Trophoblast expression of PlGF is significantly decreased in preeclampsia and by hypoxia in vitro . We hypothesize that decreased levels of cytoplasmic HuR may contribute to decreased PlGF expression in hypoxic and preeclamptic trophoblast.
Methods:  Western blots were used to determine relative effects of in vitro hypoxia on HuR protein expression and subcellular localization in trophoblast. Immunohistochemistry was used to compare HuR expression patterns in trophoblast of preeclamptic and normal placentae.
Results:  Cytoplasmic expression of HuR was decreased 1.4 fold in the cytoplasm and 1.2 fold in the nucleus of JEG3 cells. A shift in HuR was more apparent in primary trophoblast with a greater than 2-fold decrease in the cytoplasm and a 1.4 fold decrease in the nucleus following 24 hr of hypoxia. Immunohistochemical analyses detected HuR expression in near term trophoblast in situ . However, this technical approach did not detect a significant change in HuR expression between normal and preeclamptic trophoblast.
Conclusions:  HuR expression is decreased in hypoxic trophoblast, at least in vitro , which may provide a causal link to decreased PlGF mRNA expression. Down regulation of trophoblast PlGF expression is thought to contribute to the pathophysiology associated with preeclampsia including the relative lack of perfusion of the placenta and systemic renal effects.     

Comparison of assays to detect cytomegalovirus shedding in the semen of HIV-infected men

We sought to determine the optimal assays for cytomegalovirus (CMV) shedding in semen. Over a 2-month period, 149 HIV-1-infected men who have sex with men each provided up to three semen specimens. Specimens were tested for CMV by culture, rapid assay (shell vial) and polymerase chain reaction (PCR). By culture, 30% of seminal plasma and 28% of seminal cell specimens grew CMV. By rapid assay, results were 38 and 33%, respectively. By PCR, 56% of seminal cell specimens demonstrated CMV: 20% in a single semen specimen; 33% in two specimens; and 34% in all three specimens. Overall, 69% of men had CMV detected by PCR in at least one seminal cell specimen. By quantitative PCR, 14% had ten, 14% had 100, 16% had 1000, and 12% had 10 000 copies in 6.25 μl of semen analyzed. Adjusting for initial CD4+ cell count, men with CMV shedding demonstrated by PCR at the first visit were approximately four times as likely to shed CMV at a subsequent visit (RR 4.28, CI: 2.30–7.95). CMV shedding was associated with decreased CD4+ cell counts in peripheral blood (P=0.05). It is concluded that the PCR assay provided the greatest sensitivity among the three detection methods.     

A model of corrective gene transfer in X-linked ichthyosis

Single gene recessive genetic skin disorders offer attractive prototypes for the development of therapeutic cutaneous gene delivery. We have utilized X-linked ichthyosis (XLI), characterized by loss of function of the steroid sulfatase arylsulfatase C (STS), to develop a model of corrective gene delivery to human skin in vivo. A new retroviral expression vector was produced and utilized to effect STS gene transfer to primary keratinocytes from XLI patients. Transduction was associated with restoration of full-length STS protein expression as well as steroid sulfatase enzymatic activity in proportion to the number of proviral integrations in XLI cells. Transduced and uncorrected XLI keratinocytes, along with normal controls, were then grafted onto immunodeficient mice to regenerate full thickness human epidermis. Unmodified XLI keratinocytes regenerated a hyperkeratotic epidermis lacking STS expression with defective skin barrier function, effectively recapitulating the human disease in vivo. Transduced XLI keratinocytes from the same patients, however, regenerated epidermis histologically indistinguishable from that formed by keratinocytes from patients with normal skin. Transduced XLI epidermis demonstrated STS expression in vivo by immunostaining as well as a normalization of histologic appearance at 5 weeks post-grafting. In addition, transduced XLI epidermis demonstrated a return of barrier function parameters to normal. These findings demonstrate corrective gene delivery in human XLI patient skin tissue at both molecular and functional levels and provide a model of human cutaneous gene therapy.      

Induction of B cell apoptosis by co-cross-linking CD23 and sIg involves aberrant regulation of c-myc and is inhibited by bcl-2

A novel system to study the effects of co-cross-linking CD23/FceRII and sIg on murine B lymphocytes utilizes a highly multivalent form of anti- Ig prepared by covalently linking anti-Ig antibodies to a DNP-dextran backbone. CD23-sIg co-cross-linking is accomplished by the addition of DNP-specific monoclonal IgE. Previous studies demonstrated that co- cross-linking CD23 and sIg significantly inhibited mouse B cell proliferation, especially at high doses of the multivalent anti-Ig. Interestingly, examination of early activation signals reveals no difference in B cells subjected to co-cross-linking conditions as compared to B cells activated with anti-Ig alone. Total cellular protein tyrosine phosphorylation levels are unchanged by co-cross- linking. Analysis of B cell mRNA reveals that co-cross-linking the receptors does not alter the expression levels of ornithine decarboxylase 8 h after stimulation as compared to the controls. In contrast, levels of the proto-oncogene c-myc were significantly elevated 1 h after inducing B cell activation under co-cross-linking conditions. However, it remains unclear whether this aberrant c-myc regulation plays any role in inducing apoptosis. In addition, on day 3 after stimulation, the co-cross-linking of CD23 and sIg resulted in the formation of apoptotic B cells, determined by both photomicroscopy of the B cell cultures and FACS analysis of B cell nuclei. B cells obtained from bcl-2 transgenic mice proliferated as well as controls, and failed to undergo apoptosis when CD23 and sIg were co-cross-linked on their surface. These studies indicate that co-cross-linking of CD23 with B cell sIg inhibits B cell proliferation by a mechanism that is distinct from that seen by co-cross-linking of the Fc gamma RII and sIg. In addition, these results suggest a means by which antigen- specific IgE can down-regulate additional B cell activation and IgE synthesis.      

医药类专业本科物理课程的设置及目标与定位探讨

目的：探讨物理课程在高等医药类专业教育中的作用与地位。方法：对全国部分城市不同类别医院从业医务工作者进行调查，综合国际医学教育标准和我国现实医学教育以及医疗服务行业状况进行分析。结果：探讨了我国高等医药类专业教育中物理课程的设置及目标与定位问题，给出了明确的课程定位与设置标准。结论：现代医学高等教育不应忽视或淡化物理课程在医学人才培养中素质教育和专业水平提高的积极作用与基础地位，在有限的学时空间内合理安排基础性内容和与专业素质培养相关的应用内容。     

The M RNA of impatiens necrotic spot Tospovirus (Bunyaviridae) has an ambisense genomic organization.

The nucleotide sequence of Impatiens necrotic spot virus (INSV) M RNA was determined from cDNA clones. The INSV M RNA was 4972 nucleotides in length with two open reading frames (ORFs) in an ambisense genomic organization. The larger ORF near the 3' end of the viral RNA, coding for a protein with a predicted molecular weight of 124.9 kDa, was in the viral complementary sense and produced the G2 and G1 proteins. A smaller ORF in the viral sense was capable of coding for a 34.1-kDa polypeptide, designated the NSm protein. Two subgenomic RNA species were detected in INSV-infected tissue that corresponded to the predicted sizes (3.3 and 1.0 kb) of the G2-G1 and NSm mRNAs. The ORFs were separated by a 478 nucleotide A-U-rich intergenic region similar to the regions found in other viral RNAs with ambisense ORFs. The intergenic region was predicted to form a stable stem-loop structure (-81.2 kcal/mole). The ambisense genomic organization is characteristic of the S RNA for members of the Phlebovirus, Uukuvirus, and Tospovirus genera in the Bunyaviridae family. This is the first report of an ambisense Bunyaviridae M RNA.     

病灶清除内固定植骨治疗胸椎结核

目的;探讨手术治疗胸椎结核的更好方法。方法;自１９９０年以来,对２１例胸椎结核导致椎柱不稳的患者,应用病灶清除,哈氏棒内固定,椎间及椎板植骨的手术方法。本组平均３３．２岁。胸７椎体６例,胸８椎体８例,胸１０椎体７例,椎体压缩〈１／２椎体高度１３例,〉１／２椎体高度８例,并不全瘫１４例。手术中先行病灶清除,然后哈氏棒内固一,撑开后再次清除病灶,取肋骨和髂骨行椎间及椎板上植骨。术后化疗１２～１５月。结