Development in in vitro toxicology

There are three principal pressures driving the development of in vitro toxicology: (1) the need for more efficient testing systems to cope with the large number of xenobiotics currently being developed; (2) public pressure to reduce animal experimentation; and (3) a need for a better understanding of the mechanisms of toxicity. Within this, in vitro toxicology is focused on local, systemic, and target-organ toxicity. It is becoming increasingly apparent that a step or decision-tree approach using input of a variety of experimental data (physicochemical properties, biokinetics, cytotoxicity) provides the most efficient system for predicting toxicity. Examples of the use of in vitro toxicity systems for prediction of systemic toxicity and target-organ (liver) toxicity are presented.Originally presented at ECCP 93.     

Age-related changes in polyamines in memory-associated brain structures in rats

Polyamines putrescine, spermidine and spermine are positively charged aliphatic amines and have important roles in maintaining normal cellular function, regulating neurotransmitter receptors and modulating learning and memory. Recent evidence suggests a role of putrescine in hippocampal neurogenesis, that is significantly impaired during aging. The present study measured the polyamine levels in memory-related brain structures in 24- (aged), 12- (middle-aged) and 4- (young) month-old rats using liquid chromatography/mass spectrometry and high performance liquid chromatography. In the hippocampus, the putrescine levels were significantly decreased in the CA1 and dentate gyrus, and increased in the CA2/3 with age. Significant age-related increases in the spermidine levels were found in the CA1 and CA2/3. There was no difference between groups in spermine in any sub-regions examined. In the parahippocampal region, increased putrescine level with age was observed in the entorhinal cortex, and age did not alter the spermidine levels. The spermine level was significantly decreased in the perirhinal cortex and increased in the postrhinal cortex with age. In the prefrontal cortex, there was age-related decrease in putrescine, and the spermidine and spermine levels were significantly increased with age. This study, for the first time, demonstrates age-related region-specific changes in polyamines in memory-associated structures, suggesting that polyamine system dysfunction may potentially contribute to aged-related impairments in hippocampal neurogenesis and learning and memory.     

休克过程中肾上腺髓质素变化的研究进展

Adrenomedullin (AM) is a new peptidergic regulator of vascular function. AM serves as a hormone, which has many biological properties, plays an important role in the many pathophysiological processes, especially shock. This review will highlight the structure, biological properties of AM and the relationship between AM and shock.     

Seasonal variations in acute toxoplasmosis in pregnant women in Slovenia

Between December 1999 and December 2004, 40 081 pregnant women were examined for toxoplasmosis with Toxo-IgG, Toxo-IgM enzyme immunoassay. Women with positive results were then retested with the Toxo-IgG avidity assay for recent toxoplasmosis. Recent acute toxoplasmosis in pregnant women was found to be significantly more frequent (p < 0.01) during winter than summer. The incidence of acute toxoplasmosis during winter-spring was also significantly more frequent (p < 0.025) than summer-autumn. This phenomenon should be taken into account when formulating preventive measures for toxoplasmosis, especially for pregnant women.     

Uteroglobin in the developing rabbit conceptus in vivo and in vitro

Summary Uteroglobin (UGL) was measured in day- 4 to day-10 rabbit conceptuses by a competitive ELISA. Levels in blastocyst fluid, tissues, coverings and in the early fetus were determined separately. The total amount of UGL increased from 18.4 ng to 6.8 g per conceptus. The UGL content of individual day-6 blastocysts was studied in vitro. Culturing was carried out up to 60 h in Ham's F10 medium with polyvinylpyrrolidone as macromolecular component, with and without progesterone, and with progesterone plus estradiol. UGL was determined in the blastocyst fluids, tissues with coverings and in the culture media. After labelling with [³⁵S]-methionine, protein patterns of total blastocysts and of culture media were analysed by two-dimensional gel electrophoresis and fluorography. The morphology of cultured blastocysts was examined by electron microscopy. During 60 h of culture, the blastocysts expanded in diameter by 84%, and released 19% of their initial UGL content into the medium, independent of the hormonal substitution. Neither de novo synthesis, nor degradation of UGL was found: the protein remained unlabelled in fluorography, and its total quantity was not significantly different from that of non-cultured controls. Trophoblast, endoderm and embryoblast cells showed well preserved cell organelles and intercellular junctions, while the morphological differentiation of the germ layer was inhibited.     

Secular change in menarche in women in Madrid

The age at menarche was estimated by recollection in 1617 women between the ages of 18 and 60 in Madrid and a nearby suburb, Pinto. The population of Pinto is working-class and the Madrid group, taken from residential neighbourhoods , belongs to the upper middle class. In both groups we found a diminution in average age at menarche, from 14.04 to 13.02 years in Madrid and from 14.55 to 13.16 years from about 1935 to about 1965 in Pinto. These changes have been more intense in the group which is less well-off economically, where living conditions have varied much more drastically.     

The cyclic-AMP concentration in plasma and in muscle in response to exercise and beta-blockade in man

At rest the cAMP concentration in (muscle samples of) the quadriceps femoris ranged from 1.55 to 3.00 μmol per kg dry muscle and in plasma from 15.3 to 32.3 nmol per 1. Blockade of the beta adrenoreceptors with propranolol resulted in a significant decrease in the concentration in muscle at rest, the magnitude of the fall being related to the inital level. Similarly in plasma there was a trend towards lower levels of cAMP in those with the highest pretreatment levels, but the overall change was not statistically significant. There was no relation between the concentrations in muscle and plasma, before or after beta-blockade. Maximum dynamic exercise for 4–8 min resulted in an approximate doubling in the cAMP concentration in both muscle and blood. The increase in plasma was closely related to that in muscle. Beta-blockade inhibited totally the rise in cAMP in muscle during exercise but was marginally less effective in preventing the increase in blood. No increase in plasma or muscle cAMP levels during 40–70 s isometric contraction were observed.     

Cystic echinococcosis in equids in Italy

Between March 2003 and February 2007, the livers and the lungs of 2,231 horses from various Italian regions were examined for cystic echinococcosis presence at the time of slaughter. Hydatid cysts were found in six horses, namely four from Sardinia, one from Sicily, and one from Tuscany. The location, number, morphology, and fertility of the cysts found were determined. DNA was extracted from the germinal layers and protoscoleces of the fertile cysts and polymerase chain reactions (PCR) were performed in order to strain type DNA isolates for reduced nicotinamide adenine dinucleotide dehydrogenase subunit 1 (ND1), cytochrome c oxidase subunit 1 (CO1) and 12S partial genes. The PCR products were then purified and sequenced in forward and reverse. Hydatid materials obtained from positive animals were identified as Echinococcus granulosus s.s. (old G1, sheep strain) and Echinococcus equinus (old G4, horse strain) for ND1, CO1, and 12S partial genes. This allowed us to record the presence of the E. equinus in Italy for the first time with molecular tools and also to report new data on the epidemiological situation of this parasite in Italy.     

生物材料在多尺度力治疗学中应用的2022年度研究进展

随着对生物力学与力学生物学机制理解的深入,力学如何应用于疾病治疗受到越来越多的关注,由此产生了力治疗学这一新兴领域。 生物材料与力治疗学的结合,为疾病的力学治疗提供了多样化的干预途径与丰富的技术手段。 本文结合 2022 年度生物材料在力治疗学中应用的最新进展,着眼于多尺度的力治疗途径分析,从器官与组织、微组织、细胞与亚细胞和分子 4 个尺度,探讨生物材料如何服务于力治疗学应用,以期助力多学科交叉研究发展、推动力治疗研究的转化与应用。     

Pythiosis in cats in northeastern Brazil

The epidemiological, clinical and anatomopathological aspects of pythiosis in cats in northeastern Brazil are described. From January 2000 to December 2018 the Laboratory of Animal Pathology of the Federal University of Campina Grande received 1928 tissue samples of cats, three of which were diagnosed as pythiosis. Grossly, the cats showed a multinodular mass in the oral cavity associated with facial deformity (case 1), a large multinodular mass thickening the jejunum wall (case 2), and an ulcerated nodule in the skin at the base of the tail (case 3). Histologically, pyogranulomatous inflammation and necrosis, with intralesional predominantly negatively stained hyphae, were observed in all cases. Immunohistochemistry for Pythium insidiosum revealed strong immunolabelling of the hyphae. The diagnosis of pythiosis was based on the epidemiological, clinical and anatomopathological findings, and was confirmed by immunohistochemistry. Although uncommon in cats, pythiosis should be readily considered as a differential diagnosis of chronic pyogranulomatous infections of the gastrointestinal tract and skin, especially in endemic areas, where the disease is often diagnosed in other animal species.     

Genetic alterations in microRNAs in medulloblastomas

MicroRNAs (miRNAs) regulate a variety of cellular processes via the regulation of multiple target genes. We screened 48 medulloblastomas for mutation, deletion and amplification of nine miRNA genes that were selected on the basis of the presence of potential target sequences within the 3′‐untranslated region of the MYCC mRNA. Differential PCR revealed deletions in miR‐186 (15%), miR‐135a‐1 (33%), miR‐548d‐1 (42%), miR‐548d‐2 (21%) and miR‐512‐2 (33%) genes, whereas deletion or amplification was detected in miR‐135b (23%) and miR‐135a‐2 (15%). In miR‐33b, deletion, amplification or a mutation at the precursor miRNA were detected in 10% of medulloblastomas. Overall, 35/48 (73%) medulloblastomas had at least one alteration. Real‐time RT‐PCR revealed MYCC overexpression in 11 of 37 (30%) medulloblastomas, and there was a correlation between MYCC overexpression and miR‐512‐2 gene deletion (P = 0.0084). Antisense‐based knockdown of miR‐512‐5p (mature sequence of miR‐512‐2) resulted in significant upregulation of MYCC expression in HeLa and A549 cells, while forced overexpression of miR‐512‐2 in medulloblastoma/PNET cell lines DAOY, UW‐228‐2, PFSK resulted in the downregulation of MYCC protein. Furthermore, the results of luciferase reporter assays suggested that miR‐512‐2 targets the MYCC gene. These results suggest that alterations in the miRNA genes may be an alternative mechanism leading to MYCC overexpression in medulloblastomas.     

自噬在肥胖中的研究进展

Obesity is a harmful nutritional metabolic disorder to human health. Autophagy is a catabolic mechanism whereby cells degrade intracellular substances. Recent studies show that autophagy was closely correlated with insulin resistance, fat composing, and lipid droplet and triglyceride accumulation. Here, we review the association between autophagy and obesity, which may provide theoretical and experimental evidence for prevention of obesity and related diseases.     

放射基因组学在精准放疗中的研究进展

在精准医疗的背景下,放射基因组学作为一种将放射组学与基因组学结合在一起进行多组学研究的新型策略,在预测基因组结构及表达的改变、构建放射生物学的物理模型上等方面具有独到的优势。尤其是在精准放疗方面,囊括影像-基因两个维度的具有放射基因组学特点的模型可以提供多组学的信息,进而精准地指导临床决策,在提高患者生存率的同时,减少放疗带来的并发症。     

肩胛骨内固定在飘浮肩治疗中的意义

目的 探讨肩胛骨出固定治疗飘浮肩的必要性。方法 自2001年12月至2004年9月通过手术对锁骨和肩胛骨均行切复内同定治疗飘浮肩患者12例。结果 术后12例均获得随访，随访时间4个月至3年，平均2年。其中优7例，良3例，差3例(术前合并臂丛神经损伤3例)。结论 对飘浮肩患者，锁骨和肩胛骨均应行内固定，可获得满意的临床疗效。     

Differences in microcalcification in breast tumors

Summary Microcalcifications in benign and malignant tumors can be analyzed by X-ray diffraction and electron microprobe analysis in human specimen. Our systematic investigations revealed calcium hydroxyapatite in cases of invasive carcinoma but calcium oxalate (weddelite) in proliferating but non-invasive diseases. The differences in calcification depending on the underlying disease may indicate basic differences in cell metabolism.     

Pitfalls in TRAP assay in routine detection of malignancy in effusions

Telomerase has been found to be reactivated in a majority of cancers but is inactive in most somatic cells. Our principal goal was to determine the potential use of the telomeric repeat amplification protocol (TRAP) assay as marker for malignancy in cytological effusions. The simple selection criterion was the cytological diagnosis, and routine samples were classified into malignant (58 samples) and nonmalignant (233 samples). Of the malignant samples, 44/58 (76%) were positive by TRAP assay. Of the 14 telomerase-negative cytology-positive samples, RNA integrity was poor in 9, indicating suboptimal sample conservation for molecular analysis. In 3 of the remaining 5 samples with a negative TRAP assay, a high number of malignant cells was observed, and these cells might have been telomerase-negative. Thus, the sensitivity of TRAP assay for the presence of malignant cells was about 76%. In the cytologically nonmalignant effusions, the presence of telomerase activity was observed in 24% (55/233). Of these, 6% were highly suspicious for malignancy, 9% were doubtful, and 9% were cytologically nonmalignant effusions confirmed by a follow-up of 12 mo or more. According to these data, the specificity of the TRAP assay to detect tumor cells in effusions ranged only between 82-91%. Our results indicate that, although the TRAP assay is positive in 6-15% of putative malignant effusions, the relatively high number of TRAP false-negative and false-positive cases renders this test unsuitable for routine diagnostic purposes.