Palmitic acid metabolism in the soleus muscle in vitro in hypo- and hyperthyroid rats

The aim of this study was to establish whether the rate of fatty acid (FA) incorporation and its utilization by the isolated soleus muscle is modified under conditions of thyroid hormone deficit or excess. The rate of palmitic acid (PA) uptake, oxidation and incorporation into intramuscular lipids with increasing PA concentration (0.5–1.5 mM) in the incubation medium were determined. In hypothyroid rats intramuscular triacylglycerol (TG) synthesis was increased, while the rate of PA oxidation to CO₂ and incorporation into mono- and diacylglycerols (MG/DG) and phospholipids (PL) remained unchanged. In rats with triiodothyronine (T₃) excess the rate of all processes studied was enhanced, although the percentage incorporation of PA into different classes of intramuscular lipids was fairly constant and, independently of thyroid state and FA concentration in the medium, was 56–66% for TG, 9-14% for MG/DG and 24–32% for PL. Our results thus indicate that even short-term T₃ excess accelerates the rate of FA uptake and metabolism in the oxidative soleus muscle, whereas in hypothyroid rats only intramuscular TG synthesis is affected.     

丹酚酸B对缺血小鼠脑能量代谢和脑水肿的影响

目的： 通过探讨丹酚酸B（SalB）对缺血小鼠脑能量代谢的影响，研究其对脑水肿的作用。方法：将NIH小鼠分为假手术组、缺血组、SalB治疗组和尼莫地平（Nim）治疗组，测定缺血30 min时脑组织能荷（EC）、磷酸肌酸（PCr）、ATP酶活性、兴奋性氨基酸（EAA）含量以及脑含水量。结果：SalB治疗组EC（0.520±0.034）和PCr［（98.344±13.249）μmol/g］的含量、Na⁺-K⁺-ATPase［（0.593±0.013）×10³ U/g］和Ca²⁺-ATPase［（0.484±0.053）×10³ U/g］的活性明显高于缺血组EC（0.465±0.037）、PCr［（81.614±9.919）μmol/g］的含量、Na+-K+-ATPase［（0.244±0.065）×10³ U/g］和Ca²⁺-ATPase［（0.321±0.086）×10³ U/g］ 的活性，2者相比显著差异（P<0.01）；而SalB治疗组Glu［（0.405±0.110）μmol/g］和Asp［（0.141±0.020）μmol/g］的含量和脑含水量［（38.1±0.1）%］ 则明显低于缺血组Glu［（0.550±0.140）μmol/g］、Asp［（0.287±0.050）μmol/g］的含量和脑含水量［（44.1±0.1）%］，2者比较亦有显著差异（P<0.05,P<0.01）。结论：增强脑组织能量代谢和ATP酶活性，并降低脑组织中兴奋性氨基酸的含量，可能是SalB减轻小鼠缺血性脑水肿的作用机制。     

Modulation of lymphocyte proliferation by enzymes that degrade amino acids.

In a previous study we demonstrated thirteen amino acids to be essential and two to be partially essential for lymphocyte proliferation. Arginine is one of the essential amino acids, and the highly purified arginase strongly inhibited lymphocyte proliferation. The modulation of lymphocyte growth by various amino acid-degrading enzymes was studied. Peripheral lymphocytes were cultured in RPMI 1640 with or without amino acid-degrading enzyme for 72 h. A total of 17 commercial L-amino acid-degrading enzymes were studied. At 10 micrograms/ml, both lysine decarboxylase and asparaginase completely inhibited lymphocyte proliferation, arginase resulted in 78% inhibition and tyrosinase 57% inhibition. Other enzymes inhibited less than 20% lymphocyte proliferation; they included alanine dehydrogenase, arginine decarboxylase, aspartase, glutamic decarboxylase, glutamic dehydrogenase, glutaminase, histidase, histidine decarboxylase, leucine dehydrogenase, phenylalanine decarboxylase, phenylalanine hydroxylase, tryptophanase, and tyrosine decarboxylase. All four enzymes that strongly inhibited lymphocyte proliferation degraded amino acids that are essential for lymphocyte growth.     

Spontaneous activity of single neurons in the olfactory bulb of the rainbow trout (Salmo gairdneri) and its modulation by olfactory stimulation with amino acids

Summary Spontaneous action potentials recorded from 126 neurons in the olfactory bulb of Salmo gairdneri show a higher tendency towards bursting patterns of activity than those shown in previous reports about other fish. Granule cells and periglomerular cells are more likely to fire in bursts than mitral cells. Natural chemical stimulation of the olfactory mucosa with amino acid solutions produced a unique pattern of excitatory and inhibitory responses across all units. Chi-square values were calculated for stimulatory effectiveness between forty-five pairs of odours. L-serine and L-alanine consistently showed a high degree of similarity with several other odours. The converse was true for GABA and L-histidine, although this pair had a high chi-square value when mutually compared. Enantiomeric pairs of amino acids were often found to have opposite stimulatory effects on bulbar units. These results are discussed in relation to the possible properties and configurations of odorant receptor sites for amino acids in the fish olfactory mucosa.     

Ultrastructure of the neuroglial fatty metamorphosis (virchow) in the perinatal period

Summary The ultrastructure of neuroglial fatty metamorphosis (GFM) has been investigated in the telencephalic white matter of 12 premature and mature infants (gestational age 22–40 weeks; survival 0–96 days). GFM was found in all cases apart from a 22-week-old fetus, and involves predominantly astrocytic cells (68.8%), then glioblasts (43.5%), but only 7.4% of oligodendrocytes. GFM, therefore, seems to be independent of the myelination process and indicates the vulnerability of the immature neuroglial population in the metabolic and circulatory disorders of the perinatal period. Since GFM is found in almost all children dying within the early postnatal period, this subtle alteration reflects a special form of minimal brain damage. The relationship between GFM, astrocytic hypertrophy and periventricular leucomalacia and their role in the telencephalic leucoencephalopathy are discussed.

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Zusammenfassung Die Gliazellverfettung im unreifen Großhirn-Marklager wurde bei 12 Kindern ultrastrukturell untersucht (Gestationsalter 22–40 Wochen; Überlebenszeit 0–96 Tage). Die fettige Metamorphose der Neuroglia (Virchow) fand sich in allen Fällen, ausgenommen den 22 Wochen alten Feten, und betrifft vorwiegend junge Astrozyten (68,8%), ferner zu 43,5% unreife Vorstufen, jedoch nur zu 7.4% die (z.Z. der Geburt erst in Erscheinung tretende) Oligodendroglia. Die Fett-Metamorphose der unreifen Glia stellt einen sensiblen Indikator für metabolisch-zirkulatorische Störungen der Perinatalperiode dar und erfolgt unabhängig von dem Prozeß der Markscheidenbildung. Zusammen mit einer oft auffälligen Astroglia-Proliferation ist die intracytoplasmatische Akkumulation nicht membrangebundener Lipide Ausdruck einer temporären Differenzierungsstörung der unreifen Neuroglia. Die resultierende Reifungsdissoziation mit Unterdrückung der oligodendrozytären Zellinie führt zur retardierten Markscheidenbildung und dem Bild der telencephalen Leucoencephalopathie.

     

Transport of urea and amino acids through the isolated human placenta

By means of a method of two-way perfusion of the isolated human placenta the transport of urea from the fetal to the maternal placental circulation and the transport of amino acids in the opposite direction were studied. Experiments showed that the method provides for sufficiently complete perfusion of the intervillous space and creates suitable conditions for the study of placental transport. If the amino nitrogen concentrations in the two circulatory systems are equal, its concentration in the fetal circulation rises in the course of the experiment. On the addition of an amino acid to the maternal circulation, this increase develops to a greater degree. The results of these experiments confirm the view that amino acids are secreted by trophoblast cells into the fetal circulation.Laboratory of Biochemistry, Institute of Obstetrics and Gynecology, Academy of Medical Sciences of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR M. A. Petrov-Maslakov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 4, pp. 394–397, April, 1976     

弓形虫分离株表膜脂肪酸的色质谱分析

本文采用有机质谱法（ＧＣ／ＭＳ）对弓形虫不同分离株，虫体表膜脂肪酸的种类和含量进行观察分析，实验结果表明弓形虫速殖子细胞膜含有６种主要脂肪酸，范围在Ｃ１４－Ｃ１８之间，分别为肉豆寇酸、棕榈油酸、软脂酸、硬脂酸、油酸和亚油酸，而油酸和软脂酸约占总脂肪酸含量的７０％（５２－８４％）。本室自畸胎儿分离获得的ＳＨ多个虫株的脂肪酸含量及组分与国际标准人源ＲＨ株相一致，而ＳＨ４，ＳＨ（１０）与ＰＰ株，ＲＴ株相似，与平行观察的人和哺乳动物细胞膜的脂肪酸在含量与组分上均有明显差异，为鉴定分离的弓形虫株提供了实验依据。     

Effect of basic amino acids on susceptibility to carbapenems in clinical Pseudomonas aeruginosa isolates

We evaluated effects of medium composition, including basic amino acid content and pH, on susceptibility to carbapenems such as imipenem, panipenem and meropenem, in clinical isolates of Pseudomonas aeruginosa. Susceptibility to carbapenems was reduced by basic amino acids in the medium, while susceptibilities to ceftazidime and aztreonam were not. Among carbapenems, susceptibility to panipenem was most sharply reduced by addition of basic amino acids to 1:16 Mueller-Hinton agar (MHA). In 174 of 175 clinical isolates, MICs for carbapenems were affected to different degrees by medium composition. One isolate, in which MICs for carbapenems did not differ between MHA and 1:16 MHA, showed reduced production of porin (OprD). Our results suggest that susceptibility to individual carbapenems, especially panipenem, is difficult to evaluate based on MICs for other carbapenems determined on MHA. For a better prediction of antibiotic efficacy, it may be important to evaluate the susceptibility for each carbapenem individually.     

O-acylated sialic acid variants in mucinous tumours of the ovary

Summary O-acylated sialic acid variants (site 8) can be demonstrated histochemically by the PB/KOH/PAS method. They are secreted by goblet cells of the lower gastrointestinal tract, by colorectal adenocarcinomas, and by their metastases. Since the metastases are positive only when the primary tumour is positive, O-acylated sialomucins can be considered to be specific markers of colorectal adenocarcinomas if identified in metastases of a tumour of unknown origin. In our histochemical study we evaluated 29 mucinous cystomas of the ovary (23 benign and 6 malignant). We found that six cases were positive to PB/KOH/PAS. The positivity was observed in a limited number of cells and only in areas which presented an intestinal type epithelium. It was also more evident in malignant cystomas than in benign ones. We therefore think that the PB/KOH/PAS positivity can not only be considered a marker of colorectal adenocarcinomas, but also of all neoplasms which originate from an intestinal epithelium or appear to an intestinal type epithelium.This work is partially supported by the M.P.I. (40%)