Envelope gene sequences of human T-lymphotropic virus type I in Taiwan

Summary Three major types of HTLV-I had been proposed, the Melanesian type, the Zairian type, and the cosmopolitan type, which was further divided into subtypes A, B and C, according to the phylogenetic tree constructed from LTR sequences of current HLTV-I isolates. In this study, the envelope gene sequences of HTLV-I from 9 Taiwanese were analyzed. Based on the phylogenetic tree constructed by unweighed pair group method and the sequence homology analysis by GCG computer programs, the envelope gene sequences of HTLV-I proviruses from these 9 Taiwanese belonged to subtype A or subtype B of the cosmopolitan type and were closely related to HTLV-I from Japan. Twelve subtype-specific nucleotide variations were deduced from the comparison of complete or partial envelope gene sequences of 16 HTLV-I isolates of known subtypes as well as those of 9 Taiwanese. These data provided the basis for subtyping the cosmopolitan type of HTLV-I by amplification of envelope gene sequences and restriction fragment length polymorphism studies. A more extensive survey based upon this proposal was warranted.     

Fibrosis progression in chronic hepatitis C patients with occult hepatitis B co-infection.

Occult hepatitis B virus (HBV) infection in individuals without hepatitis B surface antigen (HBsAg) can be identified in hepatitis C virus (HCV) infected patients. However, its role in fibrosis progression remains uncertain. This retrospective study compared the fibrosis progression (defined as fibrosis progression by at least one stage) and progression to severe fibrosis (fibrosis stage 3 or 4) in HCV patients with occult HBV infection. Occult HBV infection was diagnosed by the detection of HBV DNA in the serum of 74 consecutive anti-HCV positive patients by PCR. Thirty-one patients (41.9%) had occult HBV infection. All 74 patients had a median of 2 (range 2-3) liver biopsies. The median time between the first and last liver biopsy was 57.7 (range 15.0-132.8) months. Eleven of the 31 patients with occult HBV infection compared with 12 of the 43 patients without occult HBV infection had fibrosis progression (35.5% versus 27.9%, respectively, p=0.608). Six of the 31 patients with occult HBV infection compared with 8 of the 43 patients without occult HBV infection developed severe fibrosis (19.4% versus 18.6%, respectively, p=0.946). In conclusion, chronic HCV patients with occult HBV co-infection does not seem to progress more than patients without occult HBV infection. However, more large-scale studies are needed before a definite conclusion can be obtained.     

A 50-kDa membrane protein mediates sialic acid-independent binding and infection of conjunctival cells by adenovirus type 37

The ocular tropism of adenovirus type 37 (Ad37) does not correlate with the wide distribution of the 46-kDa coxsackievirus and adenovirus receptor (CAR), the major receptor for most adenovirus serotypes. We previously found that Ad37 infects and binds well to conjunctival cells (Chang C), but poorly to lung epithelial (A549) cells that express CAR and hypothesized that this serotype uses a distinct receptor that is selectively expressed on conjunctival cells. To test this, we produced particles of a fiber-deleted Ad5 vector containing the Ad37 fiber protein. The "pseudotyped" vector infected Chang C cells better than A549 cells using a CAR-independent pathway. Ad37 binding was calcium-dependent and was abolished by protease digestion of cell surface proteins. Using a virus overlay protein blot assay (VOPBA), we detected calcium-dependent Ad37 binding to 50- and 60-kDa membrane proteins on permissive Chang C cells. In contrast, calcium-dependent binding was detected with only the 60-kDa protein on nonpermissive A549 cells. Ad19p, a closely related serotype that failed to bind to conjunctival cells, recognized the 60-kDa, but not the 50-kDa, protein. Ad37 has been reported to use sialic acid instead of CAR as a cell receptor on A549 cells. Pretreatment of Chang C cells with neuraminidase abolished Ad37 binding to only the 60-kDa protein, suggesting that sialic acid mediates Ad37 binding to the 60-kDa protein. The pseudotyped Ad37 vector was also able to infect neuraminidase-treated Chang C cells. Thus, subgroup D adenoviral binding to the 50-kDa protein is calcium-dependent and cell type- and serotype-specific, whereas binding to the 60-kDa protein is not necessary for infection of conjunctival cells. Together, these data suggest that the 50-kDa protein is the major receptor for Ad37 on conjunctival cells.     

Sporadic fundic gland polyps: common gastric polyps arising through activating mutations in the beta-catenin gene

Fundic gland polyps (FGPs) are the most common gastric polyps. FGPs traditionally have been regarded as nondysplastic hamartomatous or hyperplastic lesions, but their pathogenesis remains unclear. We have recently shown that somatic adenomatous polyposis coli (APC) gene alterations are frequently present in FGPs associated with familial adenomatous polyposis (FAP), raising the possibility that mutations of the beta-catenin gene affecting the APC/beta-catenin pathway might be involved in the pathogenesis of sporadic FGPs. We analyzed somatic beta-catenin gene mutations in 57 sporadic FGPs from 40 patients without FAP and in 19 FGPs from 13 FAP patients. Direct DNA sequencing of exon 3 encompassing the glycogen synthase kinase-3beta phosphorylation region for beta-catenin was used with confirmation by HIN:fI restriction endonuclease digestion. The foveolar epithelium and dilated fundic glands of the polyps were separately microdissected and analyzed in 22 of 57 sporadic FGPs. Activating beta-catenin gene mutations were present in 91% (52 of 57) of sporadic FGPs. Both the foveolar epithelium and the dilated fundic gland epithelium comprising the polyps were shown to have the same somatic beta-catenin mutation in 21 of 22 (95%) sporadic FGPs. In contrast, beta-catenin gene mutations were not present in any of the 19 FAP-associated FGPs (P: < 0.000001). The high frequency of beta-catenin mutations in sporadic FGPs indicates that these lesions arise through activating mutations of the beta-catenin gene. Beta-catenin mutations in gastrointestinal tract polyps have previously only been demonstrated in a subset of adenomatous (dysplastic) or neoplastic polyps. Sporadic FGPs are therefore the only lesions of the gastrointestinal tract to demonstrate beta-catenin mutations while lacking dysplastic morphology.     

下颌骨的应力迹线与骨小梁构筑的关系

根据下頜光弹的等倾线图,描绘出主应力迹线规迹。在下颌侧位X线照片和去除唇侧及颊侧密质骨板的标本上,观察骨密质和松质的配布,以及骨小梁的排列和方向,试行探讨骨小梁方向与主应力迹线的关系。用光弹法求得的主应力迹线有两个系列:S_1系在下颌体近水平方向,在下颌支近垂直方向分布;S_2系力线与S_1系诸力线呈正交。在标本和X线照片上,主应力迹线规迹不同程度地在骨小梁的排列上有所反映。     

The significance of somatosensory stimulations to the human foot in the control of postural reflexes

 The purpose of this study was to investigate the possible pathways in the somatosensory system that relate to the postural reflexes in the leg muscles during a sudden, toes-up platform rotation. The inputs to the cutaneous mechanoreceptors in the sole of the foot as well as to the joint receptors in the ankle joint were modulated by standing on different supporting surfaces and by immobilizing the ankle joints; and three leg muscle responses (characterized by short latency, medium latency, and long latency) to the platform movement were recorded in 15 healthy young subjects. It was found that: (1) the short latency was not affected by the changes in either plantar pressure or ankle joint movement; (2) the medium latency was regulated by the plantar pressures under the foot, as sensed by the cutaneous mechanoreceptors in the sole of the foot, and by the ankle joint movement, as perceived by the joint receptors in the ankle joint; (3) the long latency was also related to the ankle joint movement, but this relation seems to be modulated by the plantar pressures under the foot; and (4) both medium and long latencies were well correlated with the time derivative of the pressure difference between the forefoot and the rear foot regions (r=0.7), as well as with the static pressure in the antagonist foot region (r>0.6). Received: 12 January 1996 / Accepted: 30 September 1996     

A controlled trial of early adjunctive treatment with corticosteroids for Pneumocystis carinii pneumonia in the acquired immunodeficiency syndrome. California Collaborative Treatment Group

BACKGROUND. Pneumocystis carinii pneumonia remains a common cause of serious morbidity and mortality in patients with the acquired immunodeficiency syndrome (AIDS). The extensive lung injury that accompanies pneumocystis-associated respiratory failure and the reports of clinical benefit from the use of adjunctive corticosteroids provided the rationale for this prospective multicenter trial. METHODS. A total of 333 patients with AIDS and pneumocystis pneumonia received standard treatment and were randomly assigned to receive either corticosteroids (beginning with the equivalent of 40 mg of prednisone twice daily) or no additional therapy. The primary end points in this unblinded trial were the occurrence of respiratory failure (hypoxemia ratio [partial pressure of arterial oxygen divided by fraction of inspired oxygen] less than 75, intubation, or death), death, and dose-limiting toxicity of the initial standard therapy. RESULTS. Of the patients with confirmed or presumed pneumocystis pneumonia (n = 225 and n = 26, respectively), those assigned to treatment with corticosteroids had a lower cumulative risk at 31 days of respiratory failure (0.14 vs. 0.30, P = 0.004) and of death (0.11 vs. 0.23, P = 0.009), as well as a lower risk of death within 84 days (0.16 vs. 0.26, P = 0.026). The frequency of dose-limiting toxicity of the standard therapy was similar in the two treatment groups. Intention-to-treat analyses of the entire cohort confirmed these findings. Clinical benefit could not be demonstrated, however, for patients with mild disease (hypoxemia ratio, greater than 350), equivalent to a partial pressure of oxygen greater than 75 torr on room air. The patients assigned to corticosteroid treatment had an excess of localized herpetic lesions (26 percent vs. 15 percent, P = 0.04) but not of other infections or of neoplasms. CONCLUSIONS. Early adjunctive treatment with corticosteroids reduces the risks of respiratory failure and death in patients with AIDS and moderate-to-severe pneumocystis pneumonia. Because the adverse effects are few, corticosteroids should be included as part of the initial treatment for persons with AIDS who have moderate-to-severe pneumocystis pneumonia.     

医学信息学的研究领域及人才培养

医学信息学(MedicalInformatics,又称医药信息学)是计算机科学、信息科学与医学科学结合,新近形成的前沿多学科交叉的科学,它以信息论、系统论、计算机科学技术为理论基础,几乎全方位地涉及所有的医药卫生领域,已成为现代和未来生物医学发展的基石。目前,医学信息学应用的领域,面临人才短缺的现象,本文论述了在生物医学工程学科中,建立医学信息本科专业方向,通过相关课程体系的设置,培养符合社会需要的医学信息人才。