I269S Mutation in horse liver alcohol dehydrogenase S isoenzyme and its reactivity for steroids and retinoids

Ile-269 in horse liver alcohol dehydrogenase isoenzyme S(HLADH-S) was mutated to serine by phosphorothioate-based site-directed mutagenesis in order to study the role of the residue in coenzyme binding. The specific activity of the mutant(I269S) enzyme to ethanol was increased 49-fold. All turnover numbers of I269S enzyme toward 9 primary alcohols were increased. The mutant enzyme showed 3.6, 4.6, 11.6-fold higher catalytic efficiency for 5β-androstane-3,17-dione, 5β-cholanic acid-3-one and retinal than wild-type, respectively. The reaction mechanism of I269S enzyme was ordered bi bi as wild-type's. These results indicate that the hydrophobic interaction of Ile-269 residue with coenzyme plays an important role in dissociation of coenzyme from enzyme-coenzyme complex, which has been known as the rate limiting step of ADH reaction.     

Cellular Delivery of Nucleoside Diphosphates: A Prodrug Approach

Purpose. This study is concerned with cellular delivery/generation of 2′-azido-2′-deoxyuridine and -deoxycytidine diphosphate (N₃UDP or N₃CDP), potent inhibitors of ribonucleotide reductase. It characterizes the phosphorylation steps involved in the conversion of 2′-azido-2′-deoxyuridine (N₃Urd) and 2′-azido-2′-deoxycytidine (N₃Cyd) to the corresponding diphosphates and explores a prodrug approach in cellular delivery of the inhibitor which circumvents the requirement of deoxynucleoside kinases. Methods. Cell growth of CHO and 3T6 cells of known deoxycytidine kinase level was determined in the presence of N₃Urd and N₃Cyd. Activity of ribonucleotide reductase was determined in the presence of the azidonucleosides as well as their mono- or di-phosphates in a Tween 80-containing permeabilizing buffer. A prodrug of 5′-monophosphate of N₃Urd was prepared and its biological activity was evaluated with CHO cells as well as with cells transfected with deoxycytidine kinase. Results. N₃Urd failed to inhibit the growth of both cell lines, while N₃Cyd was active against 3T6 cells and moderately active against CHO cells. These results correlate with the deoxycytidine kinase levels found in the cells. Importance of the kinase was further established with the finding that the nucleoside analogs were inactive as reductase inhibitors in a permeabilized cell assay system while their mono- and di-phosphates were equally active. The prodrug was active in cell growth inhibition regardless of the deoxycytidine kinase level. Conclusions. The azidonucleosides become potent inhibitors of the reductase by two sequential phosphorylation steps. The present study indicates that the first step to monophosphate is rate-limiting, justifying a prodrug approach with the monophosphate.     

大鼠三叉神经本体觉中枢传导通路的电生理学证明

近年来形态学上发现了三叉神经领域本体感觉中枢通路,在此基础上,本文用电生理学方法,通过电刺激咬肌神经和压下颌,观察了由四级神经元组成的此通路的二级（三叉神经脊束核吻侧亚核背内侧部及邻接的网状结构）、三级（沿三叉神经感觉主核内缘存在的“带状区”）中继核团以及作为最后驿站的丘脑腹后内侧核等处的单位放电反应;另外又分别刺激或损毁二、三级中继核团,观察了丘脑腹后内侧核的单位放电变化,结果证明电刺激咬肌神经和压下颌,在上述核团都出现对本体觉冲动反应的单位放电,包括兴奋性反应单位、抑制性反应单位和无关单位三种类型,以兴奋性单位为主,占神经元单位放电总数的５２．９％～６７．７％．分别刺激二和三级神经元的所在核团,在丘脑腹后内侧核处发生相应的单位放电效应;损毁二和三级核团,本体觉传入冲动被阻断。本研究结果从电生理学上确证了形态学上发现的三叉神经本体感觉中枢通路的客观存在,从定性研究方面支持了定位研究的结果,并填补了以往生理学上只证明初级传入核团与丘脑腹后内侧核之间存在着一条多突触联系的本体觉传递通路但未能判断其具体行径和中继部位的空白,本研究并对方法论以及一些有关问题进行了讨论．     

Human papillomaviruses and papillomatosis lesions of the female lower genital tract

Objective: The objective of this study was to determine whether human papillomavirus (HPV) infections are involved in the development of papillomatosis lesions of the lower female genital tract.Methods: A total of 616 biopsy specimens of genital papillomatous lesions (307 nodular and 309 papular types) from 598 patients were anaylyzed for the presence of HPV DNA sequences by polymerase chain reaction (PCR). These specimens were also examined by histopathological assessment for characteristic HPV-associated cytological changes, by immunohistochemical staining for HPV-associated antigen, and by electron microscopy for the presence of virions.Results: HPV DNA sequences were found in 97.9% (140 of 143 cases) and 1.1% (1 of 91 cases) of the nodular and papular papillomatosis cases tested, respectively. In 18 patients who had both types of papillomatosis lesions, HPV DNA was invariably found only in nodular tissues. HPV-associated antigen, koilocytosis, and virions were found in 53.6% (98 of 183 cases), 70.5% (129 of 183 cases), and 5.9% (5 of 85 cases) of nodular papillomatosis lesions tested, respectively.Conclusions: These data suggest that nodular papillomatosis was closely associated with HPV infection, but that papular papillomatosis of the lower female genital tract may have an etiology other than HPV infection.     

Regulation of type I collagen and interstitial collagenase mRNA expression in human dermal fibroblasts by colchicine and D-penicillamine

Sclerosis is a disease process in which idiopathic hardening occurs in the skin and/or internal organs as a result of the accumulation of type I collagen, induced mainly by transforming growth factor-beta. Colchicine and D-penicillamine are widely used for its treatment. Their effects are known to be due to post-translational down-regulation of type I collagen synthesis, with colchicine also up-regulating interstitial collagenase. To determine whether or not they have any pre-translational effect on type I collagen and MMP-1, and also to observe their effects on the action of TGF-beta, cultured neonatal foreskin fibroblasts were treated with colchicine and D-penicillamine, singly and together. The amount of type I collagen and MMP-1 mRNA were quantitated by Northern blot hybridization. Colchicine suppresses the basal level of type I collagen mRNA but minimally stimulates the mRNA expression of MMP-1, whereas D-penicillamine does not have any significant effects on either. Colchicine was also able to significantly suppress the TGF-beta-induced up-regulation of type I collagen mRNA expression.     

The role of radiotherapy in the treatment of aggressive fibromatosis

Aggressive fibromatosis is a rare benign soft tissue tumor that is difficult to cure because of its infiltrative nature and high tendency to recur locally. The authors retrospectively analyzed 20 patients with histologically-confirmed fibromatosis. All patients underwent surgery with a wide or marginal margin. Five (25%) cases with histologically-negative margins had recurred. External beam radiotherapy was administered to patients whose margins were positive or who had local recurrence. However, out of concern for safety, radiotherapy was not given to two babies and a reproductive-aged woman. The average dose was 5,020 cGy. During the follow-up (mean 32.6 months), all the patients undergoing radiotherapy showed no evidence of local recurrence. A wide local excision has traditionally been the treatment of choice. However, postoperative radiotherapy could be an effective measure for preventing local recurrence in patients with a histologically-positive surgical margin and recurrence independent of any signs of relapse.     

Protective effects of garlic juice against embryotoxicity of methylmercuric chloride administered to pregnant Fischer 344 rats

In order to investigate the beneficial effects of 0.5 or 1.0 g/kg Korean garlic juice against the embryotoxicity of 20 mg/kg methylmercury chloride (MMC, CH3HgCl), pregnant Fisher 344 rats were simultaneously orally administered on day 7 of gestation. On day 20 of gestation the dams were laparotomized under ether anesthesia, and the fetuses were removed and examined for toxicity of methylmercury. Garlic juice depressed the toxicity in terms of some parameters. In the case of simultaneous treatment with 0.1 g/kg garlic juice and MMC, rates of increase were 17.5% in maternal body weight, 13.2% and 41.9% in fetal and litters' weight respectively, and 37.0% in fetal survival rate. Decreasing rates were 10.0% in maternal death rate, and 6.9% and 31.3% in pre- and post-implantation loss respectively. Decreasing rates of mercury levels in dams were 67.2% in liver, 57.6% in brain, 47.2% in kidney, 42.1% in spleen and 40.9% in blood. As well, decreasing rates of mercury level in fetuses were 54.9% in all body burden, 55.9% in liver, 46.7% in kidney and 37% in brain, respectively. The number of fetal ossification centers were reduced by 23.8% to 58.0% following simultaneous treatment with 1.0 g/kg garlic juice. These findings indicated that garlic juice effectively inhibited the embryotoxicity of methylmercury in pregnant Fischer 344 rats.     

A case of prominent epicardial fat mimicking a tumor on echocardiography

Epicardial fat may anteriorly produce an echo-free space that can be mistaken for pericardial fluid. We recently experienced a 67-year-old woman with prominent epicardial fat which was presented as an echogenic tumor-like mass. She underwent open pericardiostomy to relieve large amount of pericardial effusion. Operative findings revealed only prominent epicardial fat. Biopsy of the pericardial and fat tissues revealed an inflammation and normal fat cells without any malignant cell infiltration.     

血管紧张素Ⅱ Ⅰ型受体拮抗剂氯沙坦对急性心肌梗死的血流动力学效应

为观察口服氯沙坦(25mg,50mg)对急性心肌梗死患者的血流动力学效应,对10例急性心肌梗死患者放置漂浮导管,测量用药前及用药30min,1,2,3,4,6,9h时,收缩压(SBP)、舒张压(DBP)、平均动脉血压(MAP)、心率(HR)、外周血管阻力(SVR)、耗氧指数、心指数(CI)、肺毛压(PCWP)、左室每搏作功指数(LVSWI)、右房压(RAO)的变化。结果表明。服药后4h作用最明显,SBP、DBP、MAP、SVR、耗氧指数分别较用药前下降12％,11％,13％．14％和15％,25mg较50mg作用明显;CI轻度增加;HR、PCWP、RAP、LVSWI无明显变化。提示急性心机梗死患者口服氯沙坦产生外周阻力及心肌耗氧量下降,心指数增加等有益的血流动力学效应。氯沙坦25mg较50mg效果更明显。下壁心肌梗死早期应用需慎重。