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At least 19 recordsLinked to original sources
PubMed1985

The substrate specificity, tissue specificity and regulation of the 5' deiodination systems in rat liver and kidney tissues.

Studies were carried out to compare the 5' deiodination reactions of thyroxine (T4) and 3, 3', 5'-triiodothyronine (rT3) in rat liver and kidney homogenates. The 5'-deiodinase activity was assayed by the 3, 5, 3'-triiodothyronine (T3) produced from T4 or by the 125I-iodide released from 125I-rT3. The two 5' deiodination reactions had similar ranges of optimal pH, incubation temperature, and apparent Km, T4 1.1 and rT3 1.3 microM. However, the apparent Vmax values for T4 and rT3 deiodination reactions were 0.9 and 220 pmol/mg protein/min, respectively. Both reactions were stimulated by thiol reagent but only rT3 deiodination showed complete thiol dependence. The inhibitory effect of 6-propyl-2-thiouracil (PTU) on the 5' deiodination of rT3 was 50 times as great as that of T4. Only the 5' deiodination of rT3 was inhibited by low concentrations of calcium and magnesium. The 5' deiodination reactions in the liver and kidney tissues showed very similar substrate specificity. However, only the hepatic deiodinase activity was reduced to 60-65% of the control value after fasting, whereas the renal 5'-deiodinase activity was unaffected or even enhanced by fasting up to 72 hours. The results showed the existence of a diverse and complex 5' deiodination system in the rat tissues which is comprised of multiple similar but distinct 5'-deiodinase enzymes with respect to their substrate specificity, tissue specificity and regulation.

Animals↗
PubMed1991

Tissue-specific and non-tissue-specific heavy-chain isoforms of myosin in the brain as revealed by monoclonal antibodies.

Four types of monoclonal antibody (BM-1, BM-2, BM-3 and BM-4) each having distinctive tissue specificity were obtained by immunizing mice with purified bovine cerebrum myosin. Both BM-1 and BM-2 reacted most efficiently with cerebrum myosin and less efficiently with myosins from other limited nonmuscle tissues, the tissue specificity of BM-1 being much narrower than that of BM-2. BM-3 reacted more efficiently with several other nonmuscle myosins than with cerebellar or cerebral myosin. BM-4 recognized various nonmuscle and smooth muscle myosins with a nearly equal efficiency. Cerebral myosin as well a cerebellar myosin contained two or more electrophoretic variants of the heavy chains. BM-1 and BM-3 as well as BM-2 and BM-3 were found to recognize selectively these distinct heavy-chain isoforms. The antigenic sites of the three tissue-specific antibodies (BM-1, BM-2 and BM-3) were all localized near the head/tail junction of the myosin molecules, while that of non-tissue-specific antibody BM-4 was near the center of the tail. These and additional results indicate that mammalian brain tissues as well as several other nonmuscle tissues contain multiple heavy-chain isoforms of myosin, the levels of which differed considerably from one tissue to another.

Animals↗
PubMed1986

[Levels of tumor markers (orosomucoid, pregnancy-associated alpha 2-glycoprotein, pregnancy protein-1, placental specific-tissue protein 10, placental specific-tissue protein 12, alpha 1-fetoprotein) in the serum of patients with bronchial carcinoma].

Concentration of orosomucoid, pregnancy associated alpha 2-glycoprotein (alpha 2-PAG), Schwangerschaftsprotein 1 (SP1), placental specific-tissue protein 10 (PP10), placental specific-tissue protein 12 (PP12), alpha 1-Fetoprotein (AFP) were estimated in serum samples of 83 patients with lung cancer of stages II-IV. The proteins were determined by means of the single radial immunodiffusion, the rocket immunoelectrophoresis, the radioimmunoassay and the enzymeimmunoassay. Orosomucoid, PP12 and AFP serum concentrations of the cancer group compared with those of the control group, were increased significantly. Orosomucoid (control group: means = 0.828 g/l; s = 0.301; tumour group: mean = 2.16 g/l; s = 0.862); PP12 (control group: mean = 54.08 micrograms/l; s = 61.70; tumour group: mean = 122.52 micrograms/l; s = 131.16); AFP (control group: mean = 3.05 micrograms/l; s = 3.76; Tumour group: means = 8.29 micrograms/l; s = 17.75). alpha 2-PAG was found only in 37 cases of the tumour group; SP1 in 22 cases. PP10 (control group: mean = 2.25 micrograms/l; s = 0.866; tumour group: mean = 2.503 micrograms/l, s = 1.508). On condition that 2 tested parameters at least were estimated in the pathological range the sensitivity amounted to 0.64 and the specificity to 0.92.

Aged↗
PubMed1991

Lymphocyte subset-specific and tissue-specific lymphocyte-endothelial cell recognition mechanisms independently direct the recirculation of lymphocytes from blood to lymph in sheep.

Tissue-specific and lymphocyte subset-specific lymphocyte recirculation patterns have been analysed simultaneously. Lymphocytes obtained from one lymph compartment were directly labelled with fluorochrome in vitro and returned to the blood of the same animal. Over the next 48-72 h, the recirculation of these cells into both the same lymph compartment and at least one different lymph compartment was monitored. The cells in all of these lymph collections, as well as an aliquot of the cells used for direct fluorescent labelling, were then phenotyped with monoclonal antibodies (mAb) which define the mutually exclusive small CD4+ and CD8+ T-lymphocyte subsets in sheep. All cell samples were analysed by flow cytometry and CD4/CD8 ratios were determined for the recirculated, fluorochrome-labelled population in each lymph collection. The mean CD4/CD8 ratio calculated for each lymph compartment was then compared with the CD4/CD8 ratio calculated for each lymph compartment was then compared with the CD4/CD8 ratio of the transfused, starting population. In one experiment employing efferent prescapular lymph cells, three experiments employing efferent intestinal lymph cells, and two experiments employing afferent intestinal lymph cells, tissue-specific recirculation was observed. In all of these experiments, the pattern of recirculation of small CD4+ and CD8+ T lymphocytes was non-random. Moreover, in each experiment, this non-randomness was completely unrelated to tissue-specific phenomena, since the mean CD4/CD8 ratio of the recirculated population was higher than the CD4/CD8 ratio of the transfused, starting population regardless of the lymph compartment examined. These data are therefore consistent with the hypothesis that tissue-specific and lymphocyte subset-specific lymphocyte-endothelial cell recognition mechanisms independently direct the recirculation of small lymphocytes from blood to lymph.

Animals↗
PubMed1991

Characterization of muscle and non muscle Xenopus laevis tropomyosin mRNAs transcribed from the same gene. Developmental and tissue-specific expression.

We have isolated and characterized three Xenopus laevis tropomyosin cDNAs (XTM alpha 2, XTM alpha 4 and XTM05). XTM alpha 2 and XTM alpha 4 were isolated from a stage-42 embryo cDNA library and XTM05 from an oocyte cDNA library. XTM alpha 2 and XTM alpha 4 both code for a 284-amino-acid protein homologous to the skeletal alpha tropomyosin but diverge in their 3' untranslated sequences. This divergence is due to an absence of splicing in the early embryo. XTM05 codes for a 248-amino-acid non-muscle tropomyosin. Sequence analysis indicates that the three cDNAs are generated from a single gene which uses two promoters and possibly three sets of alternate exons. Northern blot analysis, with specific probes against each cDNA, was used to study the expression of the X. laevis alpha tropomyosin gene during development and in specific tissues. This analysis showed a different temporal usage of the two promoters and characterized the tissue-specific expression of the different transcripts.

Amino Acid Sequence↗
PubMed1978

[Tissue-specific inhibition of DNA synthesis by contactins, factors that possess tissue-specific adhesive activity].

Highly purified factors extracted from the liver and lungs of adult rats, tissue-specifically increasing the stability of intercellular contacts and of cell plasma membranes to mechanical disruption, were found to decrease, in the same manner, the labeling index (LI) in explants of the embryonic tissue of mice. The comparison of the action of these factors on the LI, and on mechanical properties of the tissue has shown that the latter effect is manifested earlier than the former one.

Adhesiveness↗
PubMed1989

Late tissue-specific toxicity of total body irradiation and busulfan in a murine bone marrow transplant model.

Total body irradiation (TBI) and busulfan were compared for late effects in a murine model of bone marrow transplantation (BMT). Male C57BL/6 mice were given fractionated TBI or busulfan given in 4 equal daily doses followed by infusion of 10(7) syngeneic bone marrow cells. Total doses of 16.4 Gy TBI and 3.4 mg busulfan were chosen for their equivalence in inducing near complete engraftment of allogeneic marrow from donor mice of the LP strain. The two treatment groups had a late wave of mortality starting at about 80 weeks after transplantation. Specific tissue damage was manifested in bone marrow stem cells, splenic T-cell precursors, hair greying and cataract formation for both TBI and busulfan but to varying degrees. Severe nephrotoxicity and anemia were observed only after TBI. Although both busulfan and TBI kill early marrow stem cells and are effective preparative agents in bone marrow transplantation, their effects on other stem cell and organ systems are not similar. In addition, many of the injuries seen are late to occur. The delayed expression of injury deserves careful long-term evaluation of BMT recipients before the therapeutic potential of effective preparative regimens can be fully appreciated.

Animals↗
PubMed1990

A tissue-specific puff (Balbiani ring a) in Chironomus thummi may contain a gene encoding a 67-kDa protein which exhibits non-tissue-specific expression.

A 2.3-kb genomic clone has been isolated from the region where the tissue-specific puff, Balbiani ring a (BRa), is found on chromosome IV of the special lobe of Chironomus thummi salivary gland cells. The clone was characterized by nucleotide sequence analysis. Two clusters of direct tandem repeats were identified, as well as large and small open reading frames (ORFs). The large ORF was fused to an Escherichia coli lacZ gene. Antibodies against the beta-galactosidase/ORF fusion protein reacted selectively on Western blots with a 67-kDa protein. Western-blot analysis and immunoelectron microscopy showed that this protein was distributed in the cells of all larval tissues examined. We concluded that BRa, a tissue-specific puff, whose activity correlates with the synthesis of 160-kDa secretory protein [Kolesnikov et al., Chromosoma 83 (1981) 661-677], may also contain a gene which is not expressed in a tissue-specific manner.

Amino Acid Sequence↗
PubMed1990

Promoter sequences from a maize pollen-specific gene direct tissue-specific transcription in tobacco.

A set of 5' promoter deletions from Zmg13, a genomic clone of a pollen-specific gene of maize, has been transcriptionally fused to a beta-glucuronidase (GUS) reporter gene in the binary vector pBI101. Tobacco leaf disks were transformed and mature plants analyzed for GUS activity directed by the Zmg13 promoter constructs. Transgenic plants containing the 375 bp Zmg13 sequence from -314 to +61 relative to the transcription start site transcribed GUS RNA and expressed active GUS enzyme in mature pollen but not in leaves. Plants transformed with a 35S CaMV promoter-GUS transcriptional fusion expressed GUS RNA in leaves but not in pollen. Neither GUS RNA or active enzyme could be detected in pollen or leaves from plants containing a 124 bp Zmg13-GUS transcriptional fusion missing the putative Zmg13 TATA box. No GUS RNA or enzyme expression was not detected in non-transformed tobacco. RNA and GUS histochemical analysis of the T1 generation confirmed that the temporal expression pattern of Zmg13-GUS transcription in tobacco followed that of the native gene in maize and that the Zmg13 promoter sequences from the maize gene are able correctly to direct genetically stable, tissue-specific gene expression in transgenic tobacco plants.

Base Sequence↗
PubMedDate not supplied

Disease-specific and tissue-specific production of unintegrated feline leukaemia virus variant DNA in feline AIDS.

Feline leukaemia viruses (FeLVs) have long been known to be associated with induction of proliferative and anti-proliferative diseases of domestic cats. Strains of FeLV have been recognized which specifically induce lymphosarcoma, aplastic anaemia, myelodysplastic anaemia, and, recently, feline AIDS (acquired immune deficiency syndrome), a naturally occurring immunosuppressive syndrome strikingly similar to human AIDS which is lethal in 100% of inoculated and viraemic specific-pathogen-free (SPF) cats. Here, we have analysed FeLV DNA in tissues of 22 SPF cats that had been inoculated with the feline AIDS strain (FeLV-FAIDS) and we find two classes of viral DNA--a monotypic common form which is detectable in bone marrow regardless of disease state, and variant forms, recognizable by restriction site differences, whose appearance correlates with onset of disease symptoms and persists throughout the course of the disease. FeLV-FAIDS variant DNA is detected at high concentration (10-50 copies per cell) and principally as unintegrated viral DNA (UVD) in bone marrow of cats with feline AIDS. In marked contrast high levels of UVD were not present in cats in the terminal-stages of T-cell lymphosarcoma, aplastic anaemia, or myelodysplastic anaemia induced by other FeLV strains. These results parallel recent observations in humans, where high levels of UVD were sometimes found in cells derived from AIDS patients infected with human T-lymphotropic virus type III (HTLV-III)/lymph-adenopathy-associated virus (LAV), and suggest that persistence of unintegrated variant viral DNA is a crucial indicator of retrovirus-induced cytopathic disease syndromes such as AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1987

A tissue-specific protein in rat osteogenic tissues.

A tissue-specific protein fraction has been detected in rat osteogenic tissue. Dissociative extraction of adult rat bone matrix with 4 M guanidinium chloride solution was followed sequentially by gel chromatography and polyacrylamide gel electrophoresis. By the latter procedure a prominent protein component of molecular weight 19,000 was isolated from the low molecular weight fraction, and antibodies directed against this protein were raised in rabbits. The antibodies were mainly against antigenic sites on this protein, as shown by protein blotting techniques. By embedding rat tissues in hydrophilic plastic and by using immunohistochemical procedures the presence of this protein was demonstrated specifically in bone matrix in vivo, in osteogenic tissue developing in diffusion chamber culture, and in a malignant osteoblast cell line (UMR 106). Soft tissues (liver, kidney, spleen, gut, skin, thymus, eye) showed no reactivity with the antiserum and in vitro a further malignant osteoblast cell line (ROS 17/2.8) did not synthesize the 19,000 molecular weight protein. This protein appears to be expressed solely by osteogenic tissue and may be used as a biochemical criterion of osteogenic differentiation.

Animals↗
PubMed1989

The three mouse multidrug resistance (mdr) genes are expressed in a tissue-specific manner in normal mouse tissues.

The gene responsible for multidrug resistance (mdr), which encodes the P-glycoprotein, is a member of a multigene family. We have identified distinct mdr gene transcripts encoded by three separate mdr genes in the mouse. Expression levels of each mdr gene are dramatically different in various mouse tissues. Specific mdr RNA transcripts of approximately 4.5, 5, and 6 kilobases have been detected. Each of the mdr genes has a specific RNA transcript pattern. These results should be considered in relation to understanding the normal physiological function of the mdr multigene family.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1985

Aryl hydrocarbon hydroxylase tissue-specific activities: evidence for baseline levels in mammalian tissues.

The tissue-specific activities (units per gram tissue) of arylhydrocarbon hydroxylase benzo[a]pyrene [AHH(BaP)] (EC 1.14.14.2) in human, mouse, rat, and hamster have been reviewed. Three categories of AHH activities are defined: baseline values from tissues that have been protected from adventitious exposures to AHH inducers; background levels from tissues where there have been no overt measures to protect against exposure; and induced levels resulting from overt exposure to chemical inducers. Evidence that the baseline category exists is derived from the observations that an upper limit of AHH tissue-specific activity of about 1.5 nmol/h . g tissue occurs in human placenta, human foreskin, lymphocyte, and epitheliod and fibroblastoid cell lines; mouse lung and liver; rat fetal liver, and noninducible rat cell lines from lung, liver, embryo kidney, and adrenals; and hamster kidney. The collected values for nonexposed tissues range from 0.02 nmol/h . g to values less than 1.5 nmol/h . g. The most consistent observation of this type was from human placental material from nonsmoking mothers. Animals raised under standard laboratory conditions without special dietary precautions show background AHH activities that range from 2 nmol/h . g to 200 nmol/h . g in portal of entry tissues such as liver, lung, and intestines. Almost all tissue samples showed induced AHH levels of up to 500 nmol/h . g when those tissues were overtly exposed to substances containing chemical inducers of AHH. Measurements of placental AHH from smoking mothers showed that more than 95% of those samples had AHH values exceeding 2.5 nmol/h . g. This natural bimodal distribution of AHH activities, across species and in different tissues, of baseline values of less than 1.5 nmol/h . g and background or induced AHH activities with values greater than 1.5 nmol/h . g, may provide a reference set of values for use in quantification of the role of AHH in the induction of disease.

Animals↗
PubMed1992

Tissue-specific nutritional regulation of angiotensinogen in adipose tissue.

Recent studies have found that angiotensinogen is expressed in white and brown fat pads, and adipocytes have been implicated as a primary source of angiotensinogen in several other tissues. The functional significance of this unexpected expression is unknown. To address this, we studied angiotensinogen messenger RNA (mRNA) expression and angiotensinogen secretion in adipose tissue and isolated adipocytes comparing fasted and refed rodents and those with genetic obesity with normal controls. Control 2-month-old Sprague-Dawley rats, those fasted for 3 days, or those fasted for 2 days and refed for 6 days were killed, and adipocytes were isolated from epididymal fat pads using collagenase digestion. Angiotensinogen mRNA was reduced to 14.6 +/- 2.3% of control levels under fasted conditions and increased to 228 +/- 53% of control levels after refeeding. Angiotensinogen release from adipocytes was reduced to 33% of control levels by fasting and increased to 183% by refeeding. These effects of fasting and refeeding on angiotensinogen regulation were tissue specific since liver angiotensinogen mRNA and serum angiotensinogen concentrations were unaffected. Systolic blood pressure, however, was modulated by fasting and refeeding in a manner parallel to adipocyte angiotensinogen expression. In related experiments, angiotensinogen secretion per epididymal fat pad of the ob/ob mouse model of obesity was increased an average of 3.4-fold compared with control. We conclude angiotensinogen expression in white adipocytes is regulated nutritionally in a tissue-specific manner. We propose that adipocyte angiotensinogen could play a previously unrecognized role in regulating adipose tissue blood supply and thereby fatty acid efflux from fat.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1991

A quantitative genetic analysis of tissue-specific catalase activity in Mus musculus.

Tissue-specific catalase activity in 3-week-old animals from inbred mouse strains 129/ReJ, BALB/c, C3H/HeAnl/Cas-1b, C3H/HeSnJ, C3H/S, C57BL/6J, and Swiss-Webster was found to be highly variable by analysis of variance (P = 0.01). Appropriate crosses were made among strains which were classified as normal (BALB/c, C3H/HeSnJ, C3H/S), hypocatalasemic (129/ReJ, C57BL/6J), and acatalasemic (C3H/HeAnl/Cas-1b) with respect to blood catalase activity to study the inheritance of the blood, kidney, liver, and lung catalase activity levels in a number of generations (reciprocal F1's, F2, two backcrosses--BC1 and BC2--and some RI lines). Segregation analysis and statistical methods which tested different models of inheritance as well as calculations of heritability were used in an effort to assess and evaluate genetic parameters that affect catalase activity. Results indicate that the inheritance of blood catalase activity in the cross involving acatalasemic and normal (BALB/c, C3H/HeSnJ) strains is compatible with the single-locus difference between the parental strains; however, the difference between the acatalasemic and the hypocatalasemic strain (C57BL/6J) would require additional genetic interaction for a satisfactory explanation. A similar pattern of generalization also applies to the inheritance of kidney catalase activity. The segregation pattern for the liver and lung catalase activity in most crosses is significantly different from the expectations of the single locus model. These results are compatible with the concept that a number of genes must affect tissue-specific catalase activity in mice. These may include previously described (e.g., Ce-1 and Ce-2) or novel genetic regulators/modifiers which interact with a single structural gene (Cas-1) or its product to produce the catalase phenotype characteristic of specific tissues in each strain.

Acatalasia↗
PubMed1989

A thyroid-specific nuclear protein essential for tissue-specific expression of the thyroglobulin promoter.

A rat thyroglobulin promoter fragment, capable of directing thyroid-specific transcription, binds at least three different factors, TTF-1, TTF-2 and UFA, which are all present in nuclear extracts of the differentiated rat thyroid cell line FRTL-5. TTF-1 and TTF-2 are FRTL-5 specific, as demonstrated by their absence in nuclear extracts prepared from cell lines that do not express any thyroid-differentiated function, while UFA is present in all cell lines tested. TTF-1 has been extensively purified. It binds to the rat thyroglobulin promoter at three different sites which share sequence homology. Mutations in two of the three sites decrease both binding of TTF-1 in vitro and promoter function in vivo. This suggests that the tissue-specific expression of the thyroglobulin genes is mediated, at least in part, by the presence of a transcription factor exclusively in thyroid cells.

Animals↗