Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Histological and histochemical aspects of the whole encephalic ventricular system of eight specimens of Bradypus tridactylus were studied. After anesthesia and perfusion, the encephalons were obtained by craniotomy. Transverse serial sections of the encephalon, stained according to Azan (Heidenhain's method) or Kluver-Barrera for nerve cells and myelinated nerve fibers; silver impregnation was carried out according to Cajal-De Castro's or Palmgren's methods. The following histochemical reactions were used: PAS (McManus), metachromasia, acid phosphatase (Gomori), Brachet's and Gomori's trichromic reaction (modified by Bargmann for neurosecretion). Histologically, different characteristics of the ependymal cells in different areas were observed, which would be related to functional peculiarities of each area of the encephalic ventricles. The ependymal cells showed discrete apical basophilia due to the presence of RNA which disappears after treatment with crystalline ribonuclease. The PAS reaction indicated the presence of a small quantity of PAS-positive substances in the apical zone of the ependymal cells and the subependymal tissue. These substances disappeared after the salivary amylase test, indicating the presence of glycogen. The acid phosphatase reaction was negative.
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PMID:Histological and histochemical study on the ependyma of Bradypus tridactylus. 116 4

A model of gastric ulceration in the rat has been used to determine the expression of four messenger RNAs (mRNAs) encoding peptides considered to play active parts in the healing response. The trefoil peptides, rat spasmolytic polypeptide (rSP) and rat intestinal trefoil factor (rITF), along with epidermal growth factor (EGF) and transforming growth factor alpha (TGF alpha) were the molecules studied. Ulceration was caused under anaesthesia by brief application of a liquid nitrogen-filled cryoprobe to the gastric serosal surface and RNA expression was monitored over the next 10 days. Each mRNA was quantified by ribonuclease protection assay, and mRNAs encoding rSP and rITF were localized within tissue sections by hybridization in situ with 35S antisense riboprobes. Ulceration induced the very rapid expression of first rSP and then rITF mRNA, whereas the mRNAs encoding EGF and TGF alpha increased at later times, with maxima recorded at 3 and 6 days, respectively. Hybridization in situ detected extensive rSP mRNA expression in the regenerative epithelia. The pronounced, but temporally different patterns of mRNA induction after ulceration suggest that the trefoil peptides may fulfil different and more immediate roles than the more 'traditional' healing proteins EGF and TGF alpha.
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PMID:Experimental ulceration leads to sequential expression of spasmolytic polypeptide, intestinal trefoil factor, epidermal growth factor and transforming growth factor alpha mRNAs in rat stomach. 779 Sep 95

Type I NOS (nNOS) catalytic activity represents the activity of full-size protein and truncated protein variants originated from many different spliced mRNA variants. Splice mRNA variants are thought to be important in determining the differential organ and subcellular expression of Type I NOS. The present study was directed to increase our understanding of the developmental regulation of Type I NOS in fetal brain. In four discrete areas of the fetal brain, we measured steady-state mRNA levels and catalytic activity and protein mass in the soluble and particulate fractions. Under general anesthesia, we collected sensory-motor cortex, striatum, hippocampus and cerebellum from sheep fetuses at 105, 115, 125 and 135 days gestation (32 fetuses). NOS protein in the soluble and particulate fractions was characterized using Western blot (molecular weight) and arginine to citrulline conversion (enzymatic activity). At the mRNA level, steady state levels were determined using probes directed against exon 2 and exon 21/22 by ribonuclease protection assay (RPA). Our data show that NOS catalytic activity is regulated in a region, subcellular and temporal manner. NOS activity was higher in the soluble fraction in all brain regions and significantly higher levels were found in the soluble fraction of striatum and particulate fraction of hippocampus (P<0.05 by ANOVA). Western blot analysis revealed three distinct molecular weight bands for Type I NOS (155, 144 and 136 kDa). The bands were present in all brain regions and in both cellular compartments with the 155 kDa band being the most abundant molecular form. Truncated protein variants accounted for 25% and 15% of total Type I NOS protein in the soluble fraction and particulate fraction respectively. RPA analysis showed a differential regulation of mRNA variants with exon 2 frame deletions in striatum and hippocampus. A coordinated increase with advancing gestational age of catalytic activity, the full-length protein, the protein variants and steady state mRNA levels was observed in cortex and striatum as demonstrated by higher levels at 125 and 135 days gestation (P<0.05 by ANOVA). NOS enzymatic activity was Ca(2+) and calmodulin dependent. However, in the particulate fraction 20% of the NOS activity was resistant to calmodulin inhibition. In summary, fetal brain Type I NOS mRNA variants are differentially regulated according to brain regions. Our data suggests that exon 2 deleted mRNA variants have low translation efficiency as indicated by the lack of parallel expression of truncated Type I NOS protein variants.
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PMID:Developmental and regional expression patterns of Type I Nitric Oxide Synthase mRNA and protein in fetal sheep brain during the last third of gestation. 1111 24