Effect of copper(II) chloride on suppression of racemization in peptide synthesis by the mixed anhydride and related methods

In segment couplings by the mixed anhydride method using isobutyloxycarbonyl chloride, the use of copper(II) chloride as an additive suppressed racemization completely in the same manner as in the carbodiimide method reported previously. This was confirmed by employing a number of couplings between Z-dipeptides and amino acid esters. The racemization-suppressing effect of other compounds were also evaluated by employing one of these model couplings to be at best only limitedly effective. Copper(II) chloride was effective also in the related method using EEDQ. Thus, in the couplings where a low level of racemization was observed without an additive, the addition of copper(II) chloride eliminated racemization even at ambient temperature where EEDQ is usually used. The effectiveness of copper(II) chloride was confirmed also in the BOP-C1 method. In the presence of HOBt racemization was reduced to a low but still detectable level, while it was suppressed completely by the addition of copper(II) chloride.     

Panoramic screening for dental anomalies assessed by professionals with identical and different backgrounds

Abstract – The aim of the present study was to evaluate how dental professionals with identical and different backgrounds assess dental anomalies viewed on panoramic radiographs. 101 panoramic radiographs performed of 9-to-10-yr-old children were examined independently by three orthodontists and two radiologists. All observers agreed on the recording of number and identification of congenitally missing permanent teeth. The observers' assessments of malpositioned teeth, teeth in infraocclusion, and primary teeth with atypical/non root resorption varied, however, to a great extent. Two of the orthodontists seemed to report only major deviations from normality (in 38 and 51 of the children respectively) while one reported several more findings (in 85 children). The radiologists reported abnormal findings in 80 and 88 children respectively. In only three children were no dental anomalies reported by any observer. The inconsistent reporting of the majority of dental anomalies (except for agenesis) in children, even among members of subgroups with a similar educational background (e.g. orthodontists), substantiates the need for an evaluation of the expedience of panoramic screening.     

混合神经动作电位的临床应用

目的研究混合神经动作电位（ＭＮＡＰ）波幅的正常值和在几种神经疾患时的改变，探讨ＭＮＡＰ的临床实用价值。方法以表面电极记录方法，检测正常人、运动神经元病、肘管综合征和周围神经病患者的ＭＮＡＰ，观察比较、分析其波幅的改变。结果肘管综合征和周围神经病患者的ＭＮＡＰ波幅明显低于正常（均Ｐ＜０．００１），而运动神经元病患者的ＭＮＡＰ波幅则无明显改变。结论ＭＮＡＰ具有一定的临床实用价值，是诊断和鉴别诊断手内肌萎缩的可靠电生理指标之一。     

Immunological detection of myeloperoxidase in poorly differentiated acute leukemia

Abstract: We performed immunocytochemical detection of myeloperoxidase (MPO), using monoclonal antibody MPO-7, in 15 consecutive cases of adult acute leukemia (AL) unclassified by conventional cytological and cytochemical criteria and 7 AML-M, with less than 10% of cytochemically MPO-positive blasts. In AL with negative MPO cytochemistry the anti-MPO reaction was positive in 5 of the 15 patients with 3, 3, 7, 11 and 45% positive blasts respectively. In AML-M₁, immunocytochemistry was positive in a larger percentage of blasts than cytochemistry in 2 cases. Immunological detection of myeloid surface markers was positive in all 15 cases of unclassified AL (including the 10 AL with negative anti-MPO reaction). Eleven of the 22 patients from this study had mixed lymphoid-myeloid phenotype. Discrepancy between immunological MPO detection and light cytochemistry was more frequent in patients with mixed immunophenotype than in patients without lymphoid markers. No relationship between MPO-antigen positivity and clinical or biological features was seen. These findings confirm immunological detection of MPO as useful for the diagnosis of poorly differentiated AL. The high incidence of inactive MPO detectable only by immunocytochemistry in mixed lineage AL needs to be confirmed.     

Neck mass with marked squamous metaplasia: a diagnostic pitfall in aspiration cytology

Fine-needle aspiration cytology (FNAC) is a highly accurate tool for the diagnosis of pleomorphic adenomas; however, this common salivary gland neoplasm can be diagnostically challenging, causing pitfalls in cytodiagnosis. A 50-year-old woman suffered from a painless, slowly-growing mass in the right posterior upper neck for 5 months. FNAC from this mass revealed many discohesive parakeratotic cells and keratin flakes, and a few stromal elements. Under the impression of metastatic well-differentiated squamous cell carcinoma, the tumor mass was totally excised. Histology confirmed a pleomorphic adenoma with marked squamous metaplasia and frequent keratin pearl formations without the evidence of malignancy. Pleomorphic adenoma occasionally reveals focal squamous metaplastic changes, when extensive, it may be misdiagnosed as metastatic well-differentiated squamous cell carcinoma in FNAC, particularly in the neck region.     

反复自然流产单向混合淋巴细胞培养

为了探讨原因不明的习惯性流产（ＲＳＡ）的发病机制，作者采用检测器官移植供、受者间ＨＬＡ－Ｄ位点抗原组织相容性程度的方法－－单向混合淋巴细胞培养＾〔１〕（单向ＭＬＣ），分别测定３５例ＲＳＡ夫妇间和２０例正常妊娠夫妇间的ＨＬＡ－Ｄ抗原相容性，并观察了ＲＳＡ和正常孕妇血浆对单向ＭＩＣ的不同影响。结果发现，ＲＳＡ夫妇单向ＭＬＣ与正常妊娠夫妇单向ＭＬＣ相对呈免疫低反应性；ＲＳＡ血浆对ＲＳＡ和正常妊娠夫妇单向     

混合植皮中自体皮岛免疫抑制效应和间接识别机理的关系初探

本文建立烧伤患者淋巴细胞与异体表皮细胞的混合培养体系（ＭＥＬＣ），并进一步添加自体表皮层细胞，以模拟混合皮肤移植时自体皮岛的局部微环境，探讨相应的免疫学机理。结果发现：１．自体表皮层细胞能有效地抑制ＭＥＬＣ反应；２．抗原加工阻断剂预处理自体表皮细胞之后，后者对自身淋巴细胞的增殖抑制现象消失或明显缓解，提示自体表皮层细胞有抗原递呈功能，参与对同种异体抗原的间接识别；３．单抗封闭实验显示ＤＲ分子不参与自体表皮的抗原递呈作用。据推测ＤＱ等非ＤＲ分子可能参与自体表皮对异体ＨＬＡ抗原的加工递呈。相应的免疫机制，有待进一步探讨。     

分段外剥内扎结合四指扩肛术治疗环形Ⅲ Ⅳ期混合痔

分段外剥内扎治疗环形混合痔配合四指扩肛术松解括约肌，治疗Ⅲ、Ⅳ期环形混合痔，近期治愈率100％。术后未发生残留皮肤水肿、肛门狭窄、排便困难及毒占膜外翻。术中注意毒占膜桥的保留，总结几点不处于同一水平面。皮桥的作用不如毒占膜桥，故可将皮肤多切除一些。     

Evidence for nonimmune mechanisms in the loss of hematopoietic chimerism in rat→mouse mixed xenogeneic chimeras

Abstract: We have recently described a relatively nontoxic, nonmyeloablative conditioning regimen allowing engraftment of T cell-depleted (TCD) rat bone marrow in mice, leading to a state of mixed xenogeneic chimerism and donor-specific skin graft tolerance, apparently by a deletional mechanism. The conditioning regimen involves depletion of host T and NK cells with mAbs, followed by administration of 7 Gy thymic irradiation (TI) and 3 Gy whole body irradiation (WBI) prior to transplantation of TCD F344 rat bone marrow cells (BMC). Although the percentage of rat cells gradually declines over time post-BMT in these animals, they demonstrate prolonged survival of donor-specific rat skin grafts and an absence of anti-rat antibody responses long after this decline is underway. We therefore hypothesized that the loss of rat hematopoietic repopulation may not be due to a loss of tolerance at the T cell or B cell level. We have now evaluated the effect of a repeat, late, donor marrow infusion on chimerism and tolerance. Treatment with 3 Gy WBI followed by TCD rat marrow infusion at 22 weeks following the original BMT led to a marked increase in rat cell repopulation of both myeloid and lymphoid lineages and prolonged the period of complete central and peripheral deletion of Vp5⁺ and Vβ11⁺ host T cells, which recognize endogenous (presumably mouse) superantigens presented by rat hematopoietic cells. Furthermore, the second marrow infusion did not induce a cytotoxic antibody response to rat marrow. Since these results suggested that the decline in rat chimerism in our model was not associated with a loss of T cell or B cell tolerance to the donor, we evaluated the possibility that a failure of NK cell tolerance led to the decline by comparing chimerism in animals receiving chronically NK cell-depleting mAb and controls. Chronic NK depletion did not markedly enhance the level of rat repopulation in any lineage. Together, our results are most consistent with the interpretation that the gradual decline in rat repopulation in our chimeras reflects a competitive advantage of host hematopoietic cells over xenogeneic cells rather than immune-mediated rejection, possibly due to species selectivity of cytokines and adhesion molecule interactions of hematopoietic progenitors and the marrow microenvironment. This host hematopoietic advantage might be counteracted by repeat donor-specific marrow infusions.