MICROCALORIMETRIC STUDIES ON THE FORMATION OF MAGNESIUM COMPLEXES OF ADENINE NUCLEOTIDES

Values for the thermodynamic quantities (DeltaF, DeltaH, DeltaS) in reactions in which complexes of adenine nucleotides with magnesium ion (ATPMg(--), ADPMg(-), AMPMg) are formed have been obtained by a microcalorimetric technique by using an isothermic Calvet's apparatus.Experimental values measured at ionic strength mu = 0.2 indicate that complex formation reactions are driven by the entropic factor and that stability of complexes increases with length of the phosphate chain.     

TREATMENT OF ACROMEGALY BY EXTERNAL IRRADIATION

Despite the place of hypophysectomy as the primary treatment in acromegaly, external radiotherapy maintains a role as a relatively slow but effective therapy for inadequately treated patients or those unsuitable for operation. Over the last 25 years our radiotherapy regimen has differed from the published series in that we give a larger dose per fraction, with fewer treatments. We have analysed the efficacy and side-effects of this regimen in 27 subjects with acromegaly. Growth hormone levels have fallen by, on average, 27% per year in the first five years, 83% of subjects achieving a basal growth hormone of less than 10 mU/l. The acute and chronic side-effects of irradiation are discussed, including the relevance of estimates of biological potency, for example the Time Dose Fraction (TDF). One patient suffered visual loss that was most likely to be secondary to the radiotherapy. We also report the histological appearances of the pituitary fossa in five subjects previously treated with radiotherapy.     

丰宫并殖吸虫囊蚴、后尾蚴透射电镜观察

目的　了解丰宫并殖吸虫囊蚴、后尾蚴的超微结构。　方法　应用透射电镜进行观察。　结果　囊蚴壁是由电子密度中等而均匀的物质构成 ,未见细胞和微管道结构。囊内幼虫和后尾蚴的体被由外皮层、肌层、皮层细胞组成 ,外皮层为一合体层 ,包括外质膜、基质、基质膜 ,外皮层表面呈指状突起 ,皮层基质内有皮棘 ,其根部位于基质膜 ,顶端被外质膜覆盖。　结论　通过透射电镜观察比较 ,囊内幼虫和后尾蚴的体被结构无明显差异性。     

大骨节病病区饮水中有机物对体外培养兔软骨细胞损伤的电镜观察

饮水有机物学说是目前大骨节病三大病因学说之一。本研究首先对陕西省榆林市大骨节病病区马家兔村及非病区长海则村和陕西省彬县大骨节病病区韩家村的饮用水采水200L,经XAD—7高效吸附树脂富集,甲醇—丙酮洗脱后,进行体外培养兔关节软骨细胞损伤实验。经透射电镜观察发现:正常对照组和溶剂对照组的软骨细胞生长正常,非病区对照组软骨细胞有微弱的损伤,病区组的软骨细胞有较明显的毒性损伤。     

REDUCTION OF THROMBUS FORMATION ON DIALYSER MEMBRANES BY ASPIRIN AND RA 233

Thrombus formation, despite efficient heparin anticoagulation, takes place on the dialysis membranes of the Gambro-Alwall dialyser, causing a high blood-loss to the patient. This thrombus formation is associated with a fall in the patient's platelet-count over the course of dialysis. To test the hypothesis that platelet retention on these membranes is an early step in the reaction leading to thrombus formation, a double-blind trial of anti-platelet agents (aspirin and a pyrimido-pyrimidine compound [RA 233]) was carried out. These agents significantly lowered platelet-adhesiveness, reduced the fall in platelet-count over the duration of dialysis, abolished the significant fall in plasminogen level seen during placebo therapy, and reduced the dialyser blood-loss. The results of the trial support the initial hypothesis and also suggest that these anti-platelet agents may be valuable in preventing thrombotic disease.     

REPLICATION AND PROPERTIES OF DNA IN NICOTINAMIDE ADENINE DINUCLEOTIDE DEFICIENCY OF Escherichia coli CELLS

When niacin-requiring E. coli was starved of niacin, a precursor of nicotinamide adenine dinucleotide (NAD), the cells elongated and synthesis of DNA was inhibited while syntheses of RNA and protein continued. The cellular NAD concentration decreased to less than one tenth of the normal level in niacin deficiency, but no change in DNA ligase level was detected. The apparent inhibition of DNA synthesis can be explained as due to reduction in the activity of the cofactor, NAD, for the enzyme.The DNA synthesized in this state was small in an alkaline sucrose gradient but of normal size in a neutral sucrose gradient. The molecules had a double-stranded structure, as judged by hydroxyapatite chromatography. The small pieces of DNA were integrated into normal-size DNA molecules on addition of niacin, when the cellular NAD concentration was restored to the normal level but DNA synthesis was not. It is suggested that this small DNA is an intermediate in DNA replication.     

酒渣鼻组织病理学的光镜和电镜观察

目的：了解３型酒渣鼻病的不同病理学和超微结构的变化，及其与人体蠕形螨寄生的关系。方法：收集１４例３型酒渣鼻活检和手术材料，作光镜和电镜观察。结果：在３型酒渣鼻病理组织中可见在扩张的毛囊和增生的皮脂腺中有人体蠕形螨寄生，在真皮浅层有不同程度慢性炎症细胞浸润。在痤疮型和鼻赘型中，尚可见毛细血管扩张、增生，其基膜变薄或呈分层状增厚，肥大细胞有脱颗粒现象。结论：皮炎型酒渣鼻病的发病与人体蠕形螨寄生有关，另两型酒渣鼻发病机理复杂，除了与人体蠕形螨寄生有关外，与细菌感染也有关。不仅有细胞、体液免疫参与，而且可能与Ⅲ型、Ⅳ型变态反应有关。