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PubMed1978

[Characteristics of lactate dehydrogenase isoenzymes of loach differentiated tissues and eggs].

The degree of inhibition by pyruvate, oxalate and urea was determined for the lactate dehydrogenase (EC 1.1.1.27) of some tissues of adult loach (Misgurnus fossilis) and for the lactate dehydrogenase isozymes, which were resistant to the inhibition by AgNO3 and dominated by their activity in the unfertilized eggs of the investigated species. It was found that the skeletal muscle lactate dehydrogenase was not sensitive to the pyruvate excess, but was inhibited by high concentrations of urea and in lower degree by oxalate. The heart muscle lactate dehydrogenase was inhibited by the substrate but only at high concentrations of the last. The main part of the eggs' lactate dehydrogenase was not sensitive to the urea, but it was very sensitive to oxalate and pyruvate. The liver lactate dehydrogenase was inhibited by urea and oxalate in the higher degree than the skeletal muscle enzyme, but after the heat inactivation of the main liver-specific isozyme the differences between them became insignificant. The skeletal muscle lactate dehydrogenase had the lower pH optima than the investigated group of the eggs isozymes. The subunit structure of the lactate dehydrogenase isozymes of different loach tissues and eggs is discussed.

Animals↗
PubMed2001

Tissue differentiation and cytokine synthesis during strain-related bone formation in distraction osteogenesis.

To investigate the contributions of various cytokines that are involved in mechanically related bone formation, we applied defined uniaxial strains in a rabbit model of mandibular elongation and examined the regenerating bone during early stages of dist raction osteogenesis by histomorphometry. We also measured serum concentrations of various cytokines during the distraction. Cell proliferation and differentiation indices correlated significantly (P<0.001) with the extent of load application. Serum concentrations of insulin-like growth factor-1 (IGF-1) decreased after osteotomy whereas transforming growth factor beta1 (TGFbeta1) showed a postoperative increase. Prostaglandin E2 (PGE2) concentrations were constant throughout the experimental period. Collagen degradation decreased slightly postoperatively and increased in samples exposed to higher magnitudes of strain. Our data show that it is the magnitude of mechanical strain that decides tissue response by a characteristic cell proliferation and differentiation. The operative trauma leads to inverse changes in serum concentrations of TGFbeta1 and IGF-1, thereby promoting the recruitment of osteoblastic precursor cells as well as collagen matrix synthesis.

Animals↗
PubMed1982

Alpha-fetoprotein in the brain of developing rats and pigs. An immunofluorescent study of cell-and-tissue differentiation.

Alpha-fetoprotein (AFP) and some other serum proteins have been studied in the developing brain of rats and pigs using the indirect immunofluorescence technique. AFP is shown to be present in the ventricular ependyma, meningeal envelopes, the choroid plexus, blood vessel walls and in a wide scale of differentiating parenchymal cells ever since early embryonic ages of both species. In brain parenchyma the content of AFP is low in immature germinative cells; in both species it starts increasing in postmigratory neuroblasts and reaches a peak at the time of accelerated nerve cell differentiation. In rats, the amount of AFP is highest towards the end of the first postnatal week; then it starts decreasing and disappears towards the end of the 3rd week. In both species AFP is localized in the cytoplasm of nerve cell perikarya and their differentiating processes. Higher concentration of this protein has often been observed at the axonal pole of the cytoplasm of differentiating pyramidal neurons. Immunoglobulin G has been found in non-parenchymal structures, and small amounts also in parenchymal cells of embryonic and early postnatal rats following a pattern of cell-and-tissue distribution similar to that of AFP. In pigs, a low amount of albumin has been shown in differentiating leptomeninges. These data suggest uptake of AFP, and some other serum proteins, from the cerebrospinal fluid into cells of the immature rat and pig brain and its increase (or higher binding) in differentiating neurons.

Animals↗
PubMed1998

Camptothecin induces differentiation, tissue transglutaminase and apoptosis in cultured keratinocytes.

Cultured normal human adult keratinocytes were exposed to (S)-(+)- camptothecin over the concentration range 10(-5) to 10(-10) M. The dose-dependent inhibition of growth was recorded using cell counting. The induction of terminal differentiation was demonstrated by the relative increase in squamous and cornified cells, and the concomitant decrease in small, proliferative cells, with an overall decrease in total cell numbers on going from 10(-10) to 10(-6) M concentration of the drug. The induction of apoptosis was studied by assay of two types of transglutaminase, "tissue" and "keratinocyte", and by assay of histone-linked mono- and oligonucleosomes. Induction of apoptosis was accompanied with increase in "tissue" transglutaminase and in the amount of nucleosomes, the latter being indicative of endonuclease activity. This activity was sharply increased at a camptothecin concentration of 10(-5) M, and may have been facilitated by "tissue" transglutaminase at lower concentrations. The data suggest that camptothecin restricts keratinocyte growth by several mechanisms including apoptosis and emphasize its possible use in topical therapy for psoriasis.

Adult↗
PubMed2003

Differential tissue shrinkage and compression in the z-axis: implications for optical disector counting in vibratome-, plastic- and cryosections.

The optical disector is among the most efficient cell counting methods, but its accuracy depends on an undistorted particle distribution in the z-axis of tissue sections. Because the optical disector samples particle densities exclusively in the center of sections, it is essential for unbiased estimates of particle numbers that differential shrinkage or compression (and resulting differences in particle densities along the z-axis) are known and corrected. Here we examined, quantified, and compared differential shrinkage and compression of vibratome-, celloidin- and cryosections. Vibratome sections showed a significant z-axis distortion, while celloidin- and cryosections were minimally distorted. Results were directly compared with previous data obtained from paraffin and methacrylate sections. We conclude that z-axis distortion varies significantly between embedding and sectioning methods, and that vibratome-, methacrylate- and paraffin sections can result in grossly biased estimates. We describe a simple method for assessing differential z-axis shrinkage or compression, as well as simple strategies to minimize the bias of the optical disector. Minimal bias can be achieved by either adjusting the placement and extent of counting boxes and guard spaces for sampling, or by applying a correction factor in cases when guard spaces are deemed essential for particle recognition.

Animals↗
PubMed1988

Cell uncoupling and protein kinase C: correlation in a cell line but not in a differentiated tissue.

Second messengers have been implicated in the control of communication between cells of various tissues and of a number of cell lines. To assess whether protein kinase C (PKC) is involved in the regulation of gap junctions between primary differentiated cells, we studied the effects of 12-O-tetradecanoylphorbol-13-acetate (TPA) on PKC translocation and junctional conductance of rat pancreatic exocrine cells. Our results show that although TPA induced the translocation of PKC from a "cytosolic" to a "microsomal" fraction within minutes, it failed to block the junctional conductance of acinar cell pairs up to 30 min after application. By contrast, analogous experiments on a liver-derived cell line (WB cells) showed that TPA-induced PKC translocation was paralleled by a marked and irreversible inhibition of intercellular coupling. These results indicate that, in contrast to the effects on transformed or dedifferentiated permanent cell lines, PKC is not involved in gating gap junctional channels between primary differentiated secretory cells of the pancreas.

Animals↗
PubMed1994

Expression of the platelet-derived growth factor beta receptor during organogenesis and tissue differentiation in the mouse embryo.

In this study we used in situ hybridization to localize expression of the platelet-derived growth factor beta (PDGF beta) receptor mRNA during organogenesis in the mouse embryo (E 9.5-16.5). Expression was first seen in periaortic mesenchyme (E 9.5-10.5). Later (E 12.5-E 16.5), the receptor was expressed in the mesenchymal component of many developing tissues and organs, particularly derivatives of the primitive gut. The expression was exceptionally high in mesenchyme directly supporting an epithelium, typical of many developing organs such as the trachea and intestine. However, as the mesenchyme differentiated into smooth muscle, PDGF beta receptor mRNA was no longer detected. The expression of the PDGF beta receptor mRNA in mesenchymal components of developing organs, along with its absence in epithelial tissues, indicates that it may play a role in mesenchymal-epithelial interactions during organ development. Somewhat unexpectedly, the PDGF beta receptor was highly expressed in the endothelium of small blood vessels and vascular structures such as the hyaloid plexus and choroid plexus. In large blood vessels, PDGF beta receptor mRNA was found in the mesenchyme surrounding the endothelium. This suggests that the PDGF beta receptor is involved in growth and development of blood vessels.

Animals↗
PubMed1999

The interaction of hydrocortisone and thyroxine during fetal adipose tissue differentiation: CCAAT enhancing binding protein expression and capillary cytodifferentiation.

Late-term fetal pigs from genetically obese dams have elevated levels of thyroid hormones and glucocorticoids, depressed levels of GH, larger fat cells and elevated lipogenesis than do fetal pigs from lean dams. We investigated the influence of elevated levels of thyroid hormones and glucocorticoids per se on adipose tissue traits by chronically treating hypophysectomized (hypox; d 70) fetal pigs between d 90 and 105 of gestation with either thyroxine (T4), hydrocortisone (HC), or the combination of T4 + HC. Treatment with T4 and T4 + HC increased serum T4 and IGF-I levels and enhanced skin and hair development. Treatment with HC and T4 + HC increased serum HC levels, fat cell size, and inner subcutaneous adipose tissue thickness. Quantitative analysis of stained adipose tissue sections indicated that T4 + HC treatment increased lipid accretion and fat cell cluster development more than did either hormone alone. The T4 + HC markedly increased apparent fat cell number, because there was only a 19% increase in fat cell size. A hypox-induced deficit in cytodifferentiation of capillaries associated with adipocytes was not influenced by T4, but was partially normalized by treatment with HC and T4 + HC. Immunocytochemical and Western blot analyses showed no influence of hormonal treatment on expression of three CCAAT enhancing binding protein (C/EBP) isoforms. However, expression of C/EBPdelta in adipose tissue was markedly reduced in control fetal pigs compared with hypox fetal pigs. These studies indicate that concurrent action of glucocorticoids and thyroid hormones may be the critical aspect of endocrine regulation of fetal adipogenesis.

Adipocytes↗
PubMed2000

Identification and characterization of Caenorhabditis elegans gamma-tubulin in dividing cells and differentiated tissues.

gamma-Tubulin is an essential component of the microtubule-nucleation machinery and therefore plays a crucial role during mitosis. To gain further insights into the function of this protein in the events that take place during embryogenesis and differentiation, we carried out detailed studies on gamma-tubulin during all the developmental stages of Caenorhabditis elegans. We identified the gamma-tubulin gene from this organism and analyzed the localization of the protein by both immunofluorescence and GFP reporter construct. We show that gamma-tubulin association with the centrosome is highly dynamic in mitotic cells, being massively recruited at prophase and released at anatelophase. This accumulation in mitotic centrosomes is dramatic during the first embryonic divisions. We provide the first description of the morphological changes at the centrosome level during the orientation of the mitotic spindle and the flattening of the posterior aster. Loss of function of the gamma-tubulin gene by RNAi induces a strong polyploidization of mitotic germ cells and embryos, but does not affect meiosis and pronuclear migration. In addition, we demonstrate the prominent redistribution of gamma-tubulin in adults at basal bodies of amphid and phasmid neurons, and at the apical membrane of polarized intestinal cells.

Amino Acid Sequence↗
PubMed1992

Differential tissue expression of multiple genes for chicken smooth muscle/nonmuscle myosin regulatory light chains.

The cDNA clones for two distinct mRNAs encoding one of the two known isoforms of chicken smooth muscle/nonmuscle myosin regulatory light chain were isolated. The nucleotide sequences of these cDNAs were very similar to each other (99% nucleotide identities) in the 516 bp translated regions and in the first 33 bp of the 3' noncoding regions, whereas the rest of the 3' noncoding regions and the 5' noncoding regions had no significant similarity. Genomic Southern blot analysis showed that these two mRNAs were encoded in two individual genes. Whereas these two genes encoded almost identical polypeptides with only one conservative substitution of amino acid residues, expression of the mRNAs was differentially regulated both at the transcriptional and translational levels in various tissues of the chicken.

Animals↗
PubMed1995

Immunohistochemical analysis of Mcl-1 protein in human tissues. Differential regulation of Mcl-1 and Bcl-2 protein production suggests a unique role for Mcl-1 in control of programmed cell death in vivo.

The mcl-1 gene encodes an approximately 37-kd protein that has significant homology with Bcl-2, an inhibitor of programmed cell death that is expressed in many types of long-lived cells. In this study we determined the in vivo patterns of Mcl-1 protein production in normal human tissues by immunohistochemical means, using specific polyclonal antisera, and made comparisons with Bcl-2. Like Bcl-2, Mcl-1 immunostaining was observed in epithelial cells in a variety of tissues, including prostate, breast, endometrium, epidermis, stomach, intestine, colon, and respiratory tract. However, often the expression of mcl-1 and bcl-2 in complex epithelia occurred in gradients with opposing directions, such that Bcl-2 immunostaining tended to be higher in the less differentiated cells lining the basement membrane, whereas Mcl-1 immunostaining was more intense in the differentiated cells located in the upper layers of these epithelia. The in vivo patterns of mcl-1 and bcl-2 expression were also strikingly different in several other tissues as well. Within the secondary follicles of lymph nodes and tonsils, for example, germinal center lymphocytes were Mcl-1 positive but mostly lacked Bcl-2; whereas mantle zone lymphocytes expressed bcl-2 but not mcl-1. Intense Mcl-1 immunoreactivity was also detected in several types of neuroendocrine cells, including the adrenal cortical cells that are Bcl-2 negative, sympathetic neurons that also contain Bcl-2, a subpopulation of cells in the pancreatic islets, Leydig cells of the testis, and granulosa lutein cells of the ovarian corpus luteum but not in thyroid epithelium, which is strongly Bcl-2 positive. Little or no Mcl-1 was detected in neurons in the brain and spinal cord, in contrast to Bcl-2, which is present in several types of central nervous system neurons. Conversely, strong Mcl-1 immunostaining was found in cardiac and skeletal muscle, which contain comparatively less Bcl-2. Additional types of cells that are Bcl-2-negative but that expressed mcl-1 include chondrocytes and hepatocytes. These findings demonstrate that mcl-1 expression is widespread in vivo and imply that the Mcl-1 and Bcl-2 proteins fulfill different roles in the overall physiology of cell death regulation.

Apoptosis↗
PubMed2006

Multi-modal and tissue-differentiated experimental pain assessment: reproducibility of a new concept for assessment of analgesics.

Experimental pain models for assessment of analgesic effect needs to be reproducible, valid and responding in a uniform way to changes in pain level. The pain system differs in various tissue types and analgesics may have different effects in different tissues. This study assessed the reproducibility of an experimental model using mechanical, thermal and electrical stimulations. Pain was evoked in three tissues: Skin, muscle and viscera. Pain was evoked and assessed in 24 healthy volunteers. The experiment was repeated three times with 30 min. intervals and twice with a weekly interval. Systematic bias, intra-class correlation (ICC) and coefficient of variation (CV) and valid sample sizes for analgesic testing were assessed. The model proved to be feasible. Most tests were unbiased, showing stable means except for the mechanical and thermal stimulation in viscera, which showed decreasing pain thresholds when the tests were repeated with 30 min. intervals. Generally the pain tests showed relatively high CV (mean 71%, range 8-145%). The pain tests showed high ICC's (>0.80) when repeated on the same day. When the tests were repeated with an interval of one week, ICC was smaller (mean 0.79 range 0.49-0.96). This means that these tests are useful for analgesic testing recruiting useful sample sizes in a crossover (mean 31 range 2-84) and a parallel study (mean 59 range 3-164) design. Application of this experimental pain model in a cross-over study design with appropriate base-line recordings offers a unique opportunity of revealing analgesic effects on pain arising from different tissues.

Adult↗
PubMed1999

Human minibrain homologue (MNBH/DYRK1): characterization, alternative splicing, differential tissue expression, and overexpression in Down syndrome.

The human homologue (MNBH/DYRK1) of the Drosophila minibrain gene maps to human chromosome 21 within the Down syndrome (DS) critical region and is within the region minimally deleted in chromosome 21-linked microcephaly. As a first step in gaining insight into the role that MNBH may have in human neurogenesis, and as a lead-up to the development of mouse models for MNBH overexpression, we have characterized the gene at the molecular level. We describe here the MNBH full-length transcript, alternative splicing, expression profile, and genomic organization. The full-length cDNA of MNBH is 5. 2 kb and is composed of 17 exons spanning 150 kb, between markers D21S335 and D21S337. Transcripts MNBHa and MNBHb arise from the use of different first exons in the 5'-UTR and are differentially expressed. MNBHa is expressed ubiquitiously in a broad spectrum of tissues and is apparently under the control of a CpG island. MNBHb is expressed only in heart and skeletal muscle and is apparently under the control of a TATA-like box. Four alternative splicing events affecting the C-terminus of the protein yield at least four isoforms of MNBH (MNBH-iso1, MNBH-iso2, MNBH-iso3, and MNBH-iso4). A PEST sequence, potentially involved in the rapid degradation of the protein, is present in all the isoforms. A histidine repeat and a serine/threonine domain are present only in the largest form of the protein (MNBH-iso1). MNBH was overexpressed 1.5-fold in DS brains and Dyrk1 about 2.1-fold in the brains of the Ts65Dn mice. The information provided here should be valuable for MNBH mutation studies and aid in the development of DS animal models.

3' Untranslated Regions↗
PubMed1979

Tissue differentiation and susceptibility to embryonal tumor induction by ethylnitrosourea in the opossum.

Opossums (Didelphis virginiana Kerr) exposed to 100 mg ENU/kg in single or incremental doses early in postnatal life developed a spectrum of epithelial and mesenchymal neoplasms including several types of embryonal neoplasms not previously induced in laboratory animals. A correlation was apparent to a varying degree between susceptibility to tumor induction and the state of morphologic maturation of the presumed target tissues at the light microscopic level for embryonal tumors of the eye, kidney, and brain. The susceptibility of the opossum eye to an ENU-induced intraocular teratoid medulloepithelioma extended over the period from 1 to between 3 and 4 weeks of age and was correlated with the differentiation of the apparent target cell, the nonpigmented ciliary epithelium of the pars ciliaris retinae. Induction of nephroblastomas was correlated with the presence in the kidney of stem cells (metanephric blastema) through the period from birth to between 6 and 8 weeks of age. Although susceptibility of the opossum brain to ENU induction of gangliogliomas was correlated with the state of differentiation of the germinal matrix from birth to 56 days of age, induction of these tumors was essentially limited to the 1st week postpartum. No definite correlation between vulnerability to tumor induction and tissue maturation was evident for a tumor of the jaw (ameloblastoma) with presumed origin from embryonic dental remnants. Our results indicated that the opossium early in postnatal life is a useful model for the induction and characterization of certain of the major dysontogenetic tumors, which have been difficult or impossible to reproduce in the traditional laboratory species.

Age Factors↗
PubMed1995

Application of fuzzy c-means segmentation technique for tissue differentiation in MR images of a hemorrhagic glioblastoma multiforme.

The application of a raw data-based, operator-independent MR segmentation technique to differentiate boundaries of tumor from edema or hemorrhage is demonstrated. A case of a glioblastoma multiforme with gross and histopathologic correlation is presented. The MR image data set was segmented into tissue classes based on three different MR weighted image parameters (T1-, proton density-, and T2-weighted) using unsupervised fuzzy c-means (FCM) clustering algorithm technique for pattern recognition. A radiological examination of the MR images and correlation with fuzzy clustering segmentations was performed. Results were confirmed by gross and histopathology which, to the best of our knowledge, reports the first application of this demanding approach. Based on the results of neuropathologic correlation, the application of FCM MR image segmentation to several MR images of a glioblastoma multiforme represents a viable technique for displaying diagnostically relevant tissue contrast information used in 3D volume reconstruction. With this technique, it is possible to generate segmentation images that display clinically important neuroanatomic and neuropathologic tissue contrast information from raw MR image data.

Adult↗