A THEORETICAL STUDY OF THE STRUCTURES OF (GLY-PRO-LEU)n AND (GLY-LEU-PRO)n*

Theoretical conformation studies have been carried out for the polytripeptides (Gly-Pro-Leu)_n and (Gly-Leu-Pro)_n and the Fourier transforms of the structures have been calculated. X-ray powder patterns of these polymers had indicated that both these polymers take up coiled-coil triple-helical structures, but in the case of (Gly-Pro-Leu)_n it was not clear whether the triple helix is formed by three parallel polypeptide chains or by a single chain folding back on itself (Scatturin et al 1975). Our studies show that both the polytripeptides can take up stereochemically satisfactory triple-helical structures with three parallel chains. There is also very good agreement between the calculated intensity distribution and that of the observed X-ray pattern, in each case.     

Effective high-dose chemotherapy with autologous bone marrow infusion in resistant ovarian cancer

Two patients with persistent minimal ovarian cancer after conventional polychemotherapy were treated with high doses of cyclophosphamide and VP 16-213 followed by autologous bone marrow infusion. Ten months afterward no clinical signs of tumor were apparent. In one patient the complete response was surgically documented. Toxicity included cardiac and pulmonary arrest during marrow infusion in one patient, but was otherwise manageable. This method of late intensification of chemotherapy in patients with persisting ovarian cancer merits further investigation.     

Choriocarcinomatous change with immunocytochemically HCG-positive cells in the gastric carcinoma of the males

Summary Gastric choriocarcinoma is a rare tumor and attracts interest because of its controversial pathogenesis. The present study reports a choriocarcinomatous change with immunocytochemically hCG-positive cells in the gastric carcinoma. The patients were males, one was 41 years old and the other 42 years old. The tumor of both cases consists of adenocarcinoma and choriocarcinoma. A sequential process of morphological transition of the adenocarcinoma to the choriocarcinoma can be traced. Indirect immunoperoxidase stain (PAP method) for human chorionic gonadotropin (hCG) demonstrates the localization of hCG in the syncytiotrophoblasts. Small number of cytotrophoblasts are weakly positive. None of the components of adenocarcinoma of both cases is positive for hCG. Human placental lactogen is not demonstrated in both cases. Stain for pregnancy specific -1 glycoprotein is weakly positive in the adenocarcinoma of one case but not in the choriocarcinoma. In one case, the concentration of hCG was 19.9mIU/ml in the preoperative serum and decreased to 1.2mIU/ml after gastrectomy. HCG production by gastric carcinoma was discussed with regard to possible pathogenesis of gastric choriocarcinoma.     

Skeletal muscle: Dependence of potassium contractures on extracellular calcium

Summary The effects of Ca-free salines were tested in frog skeletal muscle fibres. It was found that the decrease of the (Ca) in the saline from 1.8 mM to about 3.2×10^–10 M (with 4 mM Mg present) did not change the resting potential of the fibres and the depolarizations induced by 40 and 80 mM K. The action potentials, however, were significantly reduced in amplitude and duration by 24% and 33% respectively. K contractures induced with a 117 mM KCl saline had a peak and a slow component. The exposure of the fibres to a Ca-free saline [(Ca)ca. 1.6×10^–9M] for 40 sec reduced the slow component to 39±16.5% (mean±s.e; 6 fibres) of the control value. The peak component, on the other hand, was slightly decreased to 78±10.5%. These effects were reversible.The inhibition of the K contractures by extremely low (Ca)_o cannot be explained by an alteration of the electrical properties of the muscle fibres or by a depletion of the Ca content of the sarcoplasmic reticulum. It is postulated that the drastic removal of external Ca reduces the driving force for a Ca influx that may take place during the excitation of the muscle and that may be essential for the excitation-contraction coupling.This work was supported by grants from the Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina (CONICET) and, partially, from the USPHS (ROI-NS 06935-03NEUA).     

Quantitative histological studies on the aged human brain

Summary Brains from 75 people were studied to assess the occurrence of senile plaques and argyrophilic tangles in a population selected as far as possible for its probable mental normality.Histological methods were devised and validated to permit quantitative assessment of the numbers of these lesions as well as their frequency of occurrence in the two areas studied—frontal cortex and Ammon's horn.There was significant correlation between increasing age over 60 years and the proportion of patients who showed these changes at both sites. No definite relationship was found between age, site of occurrence and the intensity of the pathological changes.

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Zusammenfassung 75 menschliche Gehirne wurden untersucht, um das Auftreten von senilen Plaques und argyrophilen Fibrillen in einer wegen mutmaßlicher psychischer Unauffälligkeit ausgewählten Population zu erfassen. Die histologischen Methoden wurden standardisiert und überprüft, um eine quantitative Erfassung der Zahl und Häufigkeit dieser Läsionen in zwei untersuchten Hirnregionen — Frontalrinde und Ammonshorn — zu ermöglichen. Es fand sich eine signifikante Korrelation zwischen zunehmendem Alter über 60 Jahren und dem Anteil an Patienten mit diesen Veränderungens in beiden Regionen. Zwischen Alter, Ort des Auftretens und Intensität der pathologischen Veränderungen fand sich keine Beziehung.

     

TUVP+疝补片治疗BPH并腹股沟疝的探讨(附19例报告)

目的 探讨经尿道前列腺汽化电切术(TUVP) 疝补片治疗BPH并腹股沟疝的可行性及其优越性。方法 用杯状网塞充填疝环口，以达到修补缺损，用片状补片加强腹股沟管后壁；然后一期行TUVP。结果 术后近期效果良好，对患者创伤小、恢复快，腹股沟区无紧缩感，疼痛轻。拔除尿管后患者排尿顺畅，伤口愈合好。近期无术后并发症及疝复发现象。结论 TUVP 疝补片一期治疗前列腺增生症并腹股沟疝，疗效良好。特别是对高龄BPH并腹股沟疝同时又并有其他内科疾患的病人，更显示出其优越性和实用性。     

Characteristics of Acid Reflux in Blarrett‘s Esophagus

Barrett's esophagus is a precancerous condi-tion in which the squamous mucosa of the esopha-gus is replaced by columnar epithelium.Patientsunder this condition are at greater risk for the de-velopmentof esophagealadenocarcinoma.Barrett'sesophagus is an acquired condition resulting fromlongstanding gastroesophageal reflux disease[1] .But only approximately1 0 % of patients with re-flux esophagitis develop Barrett's esophagus.Thisstudy analyzed the correlation of acid reflux withreflux esophagi…     

H n.m.r. spectrum from the flexible N-terminal segment of Streptomyces subtilisin inhibitor

The ¹H n.m.r. spectrum of Streptomyces subtilisin inhibitor shows a limited number of unusually sharp signals at room temperature. Some of these signals are assigned uniquely to protons of the side chains of the N-terminal segment, Aspl-Ala2-Pro3-Ser4-Ala5-Leu6-Tyr7-based on experiments of spin decoupling, pH titration, and enzymatic cleavage of the protein. Quantitative examination of these signals indicates that the N-terminal end of this protein is heterogeneous in that the protein contains a considerable fraction whose sequence starts with Ala2 rather than with Asp1. The pK_a values for the amino groups of Asp1 and Ala2 exposed at the N-terminus are determined to be 8.9 ± 0.4 and 9.0 ± 0.1, respectively. Furthermore, examination of the line-widths of the methyl proton resonances of Ala2 and Ala5 residues indicates that the N-terminal peptide segment is free and undergoes rapid segmental motions in the order of 10^?9s.