Lipid peroxidation in tissues during subliminal electrostimulation of limbic system structures in the brain

The experiments on rats have shown that during prolonged subliminal electrostimulation of limbic brain system structures peroxidation is enhanced in the blood and tissues (myocardium, liver, parodontium), with it being realized via activation of sympathoadrenal and hypothalamo-hypophyseal systems and stipulated by the failure of physiologic antioxidative mechanisms.     

Effect of biogenic stimulators--aloe extract and biotrite--on lipid peroxidation processes in saliva in inflammatory periodontal disease

The influence of biostimulators of vegetative origin, such as aloes and biotritis, on the process of lipid peroxidation in parodontium tissues, was studied. Biotritis has a more considerable parodontoprotective effect than aloes.     

Morphologic and pathologic findings in teeth and jaws from the middle bronze age (Pitten, Lower Austria)

The detailed examination of the masticating apparatus of 18 skulls from the Middle Bronze Age in Pitten (Lower Austria) revealed numerous pathological findings of the teeth. Most remarkable were frequency and extent of dental abrasions. In addition to it, indications on inflammatory processes in the marginal parodontium were obtained, combined with partly immense formations of concrements on the surfaces of the teeth. The incidence of dental caries was relatively low. Abnormal positions of the teeth and pathological processes concerning the development of dentition as well as the eruption of the wisdom teeth could be observed repeatedly. Conclusions on insufficiences of the oral hygiene in this time follow especially from the concrement findings and from the inflammatory reactions of the marginal parodontium.     

内皮细胞间连接的研究进展

内皮细胞形成了大分子物质和循环细胞从知液到细胞的最主要屏障,内皮细胞的通航性主要是通过内皮细胞间连接进行调控的,本文从内容细胞间连接的几种方式,信号的传导,连接变化的调控,篾这中液体的流动及中性粒细胞渗出对内皮细胞间连接的影响进行阐述,讨论了目前内皮细胞间连接的研究进展,提出内皮细胞间连接和骨架结构对血管通透性的调控,中性粒细胞的渗出和血管内皮细胞间连接的重建都具有非常重要的作用,其中内皮细胞的渗     

Brain hypoxia and the role of active forms of oxygen and of energy deficit in the neuron degeneration

The concepts about physiological mechanisms of oxygen transport to the brain have recently changed substantially. Precise data on the capillary blood flow rate, on a substantial dispersion of corresponding values, on the influence of the capillary blood flow rate on pO2 in the capillaries and tissues have evolved. Krog's paradigm about an exclusive role of capillaries in the gas exchange between the blood and tissues amounting to almost 100 years was abandoned. All these data also changed the concepts about the development of various types of hypoxia in the brain tissues. The study of pO2 in the brain at normoxia showed that pO2 exhibits the fluctuations from 1-2 to 80-85 mm Hg. This means, in particular, that hypoxic phenomena take place in the normal healthy brain. During hypoxia the mass adhesion of leukocytes to the walls of microvessels was shown to hamper the capillary blood flow and can become one of the reasons for the death of the brain during hypoxia. The brain hypoxia is not an occasional pathologic process. It exists in an intact brain owing to physiological fluctuations of pO2 in various microregions of the brain. It occurs during various physiological states in the norm and also during various illnesses associated with the changes and disruptions in the oxygen transport. The final stage of hypoxia is the destruction of the cells. The development of this process and its particular reasons are nowadays the subject of multiple physiological and biochemical studies. Certain changes are introduced into modern ideas about the reasons for the degradation of the nervous cells upon hypoxia. The degradation of the neurons during hypoxia or anemia is postulated to be associated not only with the cell generation of active forms of oxygen (AFO), but also with the energy deficiency. This means a deficient synthesis or a complete absence of ATP in a cell during hypoxia, anemia, and ishemia.     

MicroRNAs; easy and potent targets in optimizing therapeutic methods in reparative angiogenesis

The age‐related senescence of adult tissues is associated with the decreased level of angiogenic capability and with the development of a degenerative disease such as atherosclerosis which thereafter result in the deteriorating function of multiple systems. Findings indicate that tissue senescence not only diminishes repair processes but also promotes atherogenesis, serving as a double‐edged sword in the development and prognosis of ischaemia‐associated diseases. Evidence evokes microRNAs (miRNAs) as molecular switchers that underlie cellular events in different tissues. Here, miRNAs would promote new potential targets for optimizing therapeutic methods in blood flow recovery to the ischaemic area. Effectively beginning an ischaemia therapy, a more characteristic of miRNA changes in adult tissues is prerequisite and in the forefront. It may also be a preliminary phase in treatment strategies by stem cell‐based therapy.     

成体干细胞的研究及潜在应用

成体干细胞(adultstemcells)存在于人和哺乳动物的多种成体中,具有自我更新和一定的分化潜能.现已从骨髓、软骨、血液、神经、肌肉、脂肪、皮肤、角膜缘、肝脏、胰腺等许多组织中获得干细胞,并在部分成体干细胞的体外分离培养、扩增及诱导分化等研究中取得突破性进展,发现部分成体干细胞具有预想不到的分化潜能.成体干细胞不仅是发育生物学研究的理想模型,而且是细胞移植治疗、人工组织或器官构建的种子细胞和基因治疗的理想载体细胞,因此,在揭示生命的本质和规律及再生医学中有十分广阔的应用前景.     

The role of angiogenic growth factors in organogenesis

Angiogenic growth factors are a class of molecules which exert a fundamental role in the process of blood vessel formation. Besides vasculogenic and angiogenic properties, these compounds mediate a complex series of patterning activities during organogenesis. Angiogenic factors cooperate in the growth and development of embryo tissues in a cross-talk between endothelial cells and tissue cells. It is well established that many tissue-derived factors are involved in blood vessel formation, but there is now emerging evidence that angiogenic factors and endothelial cells themselves represent a crucial source of instructive signals to non-vascular tissue cells during organ development. Thus, angiogenic factors and endothelial cell signalling are currently believed to provide fundamental cues for cell fate specification, embryo patterning, organ differentiation and postnatal tissue remodelling. This review article will summarize some of the recent advances in our understanding of the role of angiogenic factors and endothelial cells as effectors in organ formation.     

Self-Renewal of the Adult Skeletal Muscle Satellite Cell

The concept of the stem cell has evolved in dynamic systems such as those involved inembryonic development and, in the adult, in tissues such as blood and skin which arecontinuously renewed. It has proved difficult to establish whether stem cell mechanismsunderlie the maintenance of the more stable tissues that form the majority of the adultbody. We have investigated skeletal muscle, a low-turnover and largely postmitotictissue which nevertheless maintains a remarkable capacity to regenerate itself followinginjury. The contractile units of muscle are myofibers, elongated syncytial cells eachcontaining many hundreds of postmitotic myonuclei. Satellite cells are resident beneaththe basal lamina of myofibers and function as myogenic precursors during muscleregeneration. We have recently demonstrated that as few as seven Pax7+ satellite cellsassociated with one myofiber can regenerate a hundred or more new myofiberscontaining thousands of myonuclei. Satellite cells also undergo self-renewal, givingthem the ability to participate in multiple rounds of injury-induced regeneration. Thesatellite cell may thus serve as a prototype for stem cell function in stable adult tissues: atissue-specific progenitor which is normally quiescent but which has self-renewalproperties similar to those of better known stem cells.     

A hybrid bioregulatory model of angiogenesis during bone fracture healing

Bone fracture healing is a complex process in which angiogenesis or the development of a blood vessel network plays a crucial role. In this paper, a mathematical model is presented that simulates the biological aspects of fracture healing including the formation of individual blood vessels. The model consists of partial differential equations, several of which describe the evolution in density of the most important cell types, growth factors, tissues and nutrients. The other equations determine the growth of blood vessels as a result of the movement of leading endothelial (tip) cells. Branching and anastomoses are accounted for in the model. The model is applied to a normal fracture healing case and subjected to a sensitivity analysis. The spatiotemporal evolution of soft tissues and bone, as well as the development of a blood vessel network are corroborated by comparison with experimental data. Moreover, this study shows that the proposed mathematical framework can be a useful tool in the research of impaired healing and the design of treatment strategies.     

Immunocytochemical localisation of PTHrP (parathormone-related peptide) in myoepithelial cells of human sweat and parotid glands.

PTHrP is a HHM-inducing peptide. It exhibits certain structural similarity to PTH and the two hormones may act through the same receptors. PTHrP is known to be produced in various tissues as well as during development. In this study we decided to immunocytochemically demonstrate PTHrP in normal skin and squamous cell carcinomas as well as in parotid glands (normal, inflamed and neoplastic). In the skin, PTHrP expression was demonstrated in epidermis and in smooth muscle cell layer of blood vessels. In squamous cell carcinomas, the expression was noted in foci of keratinization. In parotid glands, the peptide was localised in excretory ducts and in blood vessels, while inflammation of the gland and its tumours resulted most frequently in the less intense immunoreaction. The results are consistent with those of other authors. The novel observations include demonstration of PTHrP expression in myoepithelial cells of sweat glands and in parotid glands, where it may be involved in the control of their contractile activity.     

Runx1 modulates developmental, but not injury-driven, hair follicle stem cell activation

Aml1/Runx1 controls developmental aspects of several tissues, is a master regulator of blood stem cells, and plays a role in leukemia. However, it is unclear whether it functions in tissue stem cells other than blood. Here, we have investigated the role of Runx1 in mouse hair follicle stem cells by conditional ablation in epithelial cells. Runx1 disruption affects hair follicle stem cell activation, but not their maintenance, proliferation or differentiation potential. Adult mutant mice exhibit impaired de novo production of hair shafts and all temporary hair cell lineages, owing to a prolonged quiescent phase of the first hair cycle. The lag of stem cell activity is reversed by skin injury. Our work suggests a degree of functional overlap in Runx1 regulation of blood and hair follicle stem cells at an equivalent time point in the development of these two tissues.     

Endothelial signaling during development

Blood vessels perfuse all tissues in the body and mediate vital metabolic exchange between tissues and blood. Increasing evidence, however, points to a direct role for paracrine signaling between blood vessel cells and surrounding target organ cells, during embryonic development and cell differentiation. Understanding the nature of this signaling and its heterogeneity, both in the embryo and in adult tissues, may not only provide insights into mechanisms for normal developmental cell fate decisions, but could also lead to novel targeted therapeutic approaches for a variety of diseases such as heart disease, diabetes or cancer.     

The Recirculation of Naive and Memory Lymphocytes

It has been clearly shown that continuous recirculation of lymphocytes is crucial for the development of primary immune responses and that naive CD4 cells are distinguished from memory CD4 cells by differences in expression of several adhesion molecules. These findings suggest that changes in migratory behavior accompany the naive to memory cell transition. This area is first reviewed and then to evaluate this hypothesis, we compare the tissue distributions of highly purified naive and memory CD4 cells after transfer to syngeneic recipients. Naive cells which express high levels of L-selectin, and low levels of α4 and β2 integrins, and CD44 localized in secondary lymphoid organs and were detectable in these tissues and in the blood for several weeks after transfer. Memory cells. which have a reciprocal phenotype, showed a markedly different distribution, particularly with respect to tissues where entry is controlled through high endothelial venules.     

Approaches to studying cell adhesion molecules in angiogenesis

Capillaries provide a vast interface between the blood and the tissues that is crucial for regulating nutrient delivery, blood coagulation and transmigration of leukocytes to sites of infection. The growth of new capillaries from pre-existing vessels (angiogenesis) is essential for normal embryogenesis and growth, but also occurs in the development of many diseases. Although relatively little is known about endothelial cell biology, progress is nevertheless being made towards understanding angiogenesis, and several laboratories have begun to identify cell adhesion molecules that may be required for the growth of microvessels.     

The multiple promoter methylation profile of PR gene and ERalpha gene in tumor cell lines

The changes of methylation status of various gene promoters are a common feature of malignant cells and these changes can occur early in the progression process. Therefore, abnormal methylation can be used as cancer marker. Such studies will first require the development of a panel of methylated markers that are methylated in cancer tissues but unmethylated in normal tissues or methylated status is different between cancer tissues and normal tissues. By using methylation-specific PCR (MSP) assay method, we observed alterations in DNA methylation at the double promoter regions of the progesterone receptor (PR) gene and estrogen receptor (ERalpha) gene in various tumor cell lines. Compared with normal white blood cell, the methylation status of PRA promoter in various cancer cell lines changed from unmethylation pattern to methylation pattern. That of PRB promoter changed from both unmethylated and methylated alleles to only methylated allele. The methylation status of ERalpha-A and ERalpha-B promoter in various cancer cell lines are cell -specific. This study indicates that PR promoter methylation may be a molecular marker in various cancer detections. And the methylation status of ERalpha-A and ERalpha-B is cell-specific.     

Expression of sarcolectin in the human pituitary gland and amniotic fluid

Sarcolectin (SCL) is a 55 kDa protein cross-reacting with a cytokeratin 7 monomer found in placental blood, sarcomas and various tissues. It blocks the synthesis of interferon-dependent secondary proteins, induces cell DNA activation and sensitizes cells to viral infection. SCL is a potent promoter of tissue growth. In the present report, we demonstrate that SCL is expressed in the human pituitary gland at the mRNA and protein levels. We show also its presence in human amniotic fluid in high titres while interferon titres is weak. These results allow to postulate a potential role of SCL as a growth factor participating in human foetal development.     

Differential Expression of Oncogenicity and Nopaline Synthesis in Intact Leaves Derived from Crown Gall Teratomas of Tobacco

The results reported in the present study demonstrate that oncogenicity and nopaline synthesis are differentially expressed under conditions in which the neoplastic state is persistently suppressed in crown gall teratoma tissues of tobacco. While an active and continued synthesis of nopaline occurs in cells present in intact teratoma-derived leaves, the reexpression of oncogenicity depends on the development of new cell divisions. It is suggested that these new cell divisions are required either (a) to reestablish positive feedback control mechanisms upon which the development of a capacity for autonomous growth of these plant tumour tissues appears to depend, or (b) to establish the pattern of metabolism concerned with cell growth and division which is then maintained in the plant tumour cells by positive feedback control mechanisms.     

Distribution, cellular localization, and postnatal development of VASP and Mena expression in mouse tissues

Vasodilator-stimulated phosphoprotein (VASP) and mammalian Enabled (Mena) are members of the proline-rich Ena/VASP protein family that links the cell membrane proteins, signal transduction pathways, and the actin cytoskeleton. VASP and Mena, substrates of cyclic nucleotide-dependent protein kinases, are associated in different cell types with microfilaments, focal adhesions, cell-cell contacts, and highly dynamic membrane regions. Here, the analysis of mRNA and protein expression, cellular localization, and postnatal development of VASP in different mouse tissues is reported and compared with that of Mena. The expression levels of VASP and Mena differ markedly among various tissues and cell types. The highest levels of VASP are observed in platelets, but stomach, intestine, spleen, lung, and blood vessels are also rich sources of VASP. Mena is abundantly expressed in brain, whereas it is not detectable in platelets and spleen. In intestine and stomach, prominent VASP and Mena immunoreactivity is detected in intestinal smooth muscle cells and blood vessels and cellular membranes of epithelial cells. In kidney, VASP and Mena are abundantly expressed in glomerular mesangial cells and in papilla. VASP and Mena immunoreactivity in heart is associated with blood vessels and with the intercalated discs of cardiac myocytes, where they colocalize with connexin-43. During postnatal development of heart, the level of VASP and Mena expression gradually decreases from neonatal to adult animals. The data demonstrate a clear colocalization of VASP and Mena in cells of stomach, intestine, kidney, and heart. These data and other recent developments suggest that proteins of the Ena/VASP family exert similar functions and may compensate for each other in these tissues.