Biomedical subjects
Publications and source records attributed to F He.
The goal of treating true ankylosis of TMJ was to reconstruct the function of the joint and to prevent relapse. The authors have operated on 26 patients with true ankylosis of TMJ using semi-joint replacement of compound non-biological materials. Functionally and cosmetically good results were demonstrated after two to thirteen months' follow-up.
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Glycidamide (GA) is an epoxide metabolite of acrylamide (AA). Neurotoxicity of both GA and AA was compared by their performance in behavioral, neuro-biochemical and neuropathological studies. Male rats were injected peritoneally with AA (25 or 50 mg/kg) or GA (50 or 100 mg/kg) once daily for eight days. Results showed that toxic effects of AA were greater than those of GA in wheel rotation test, hind limb splay test, and activities of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in peripheral nerves in rats. Results of neuropathological examinations in experimental rats also provided evidence that AA could cause damage to peripheral nerves, but GA did not. It indicated that nerve tissue was more vulnerable to AA than to GA. Also, it suggested that neurotoxic effects of AA was caused by itself, and influenced less by its metabolite GA.
The authors introduced casing aspiration needle system (CANS) to irrigating root canal. The effect of root irrigation on removing canal debris and the variance of apical foramen pressure on extracted teeth were compared between the conventional irrigation and CANS irrigation. The results indicated that the effect of root canal irrigation by CANS was much better than the conventional method (P < 0.01). CANS irrigation didn't produce pressure to apical foramen during root canal irrigation. However, in the conventional method, with irrigation needle inserted deeper and deeper in root cancal the pressure of apical foramen gets higher and higher.
Treatment of cells with the DNA-alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) induces expression of the endogenous mammalian DNA polymerase beta (beta-pol) gene and of the cloned promoter in transient expression studies. The lone cAMP response element (CRE) in the core promoter, along with functional protein kinase A, is critical for the MNNG-induced up-regulation. Recently, we described a kinetic mechanism for transcriptional regulation of the beta-pol promoter in vitro and found that CRE-binding protein (CREB) from MNNG-treated cells differentially up-regulates the promoter by stimulating formation of closed preinitiation complex (RPc). Here, using a CRE-dependent chimeric beta-pol promoter, we purified the RPc assembled with nuclear extract from MNNG-treated and control HeLa cells. Comparison of proteins in the purified RPc samples revealed that the MNNG induction is associated with a strong increase in the Ser133-phosphorylated form of recombinant CREB (CREB-1). CREB depletion of the nuclear extracts diminished transcriptional activity, and addition of purified Ser133-phosphorylated CREB-1 restored activity, whereas unphosphorylated CREB-1 did not. Addition of phosphorylated CREB-1 to the control cell extract mimicked the MNNG-induced up-regulation of transcriptional activity. These results indicate that phosphorylation of CREB-1 is the probable mechanism of activation of the beta-pol promoter after treatment of cells with the DNA-alkylating agent MNNG.
Tyrosine kinases play central roles in the growth and differentiation of normal and tumor cells. In this study, we have analyzed the general tyrosine kinase expression profile of a prostate carcinoma (PCA) xenograft, CWR22. We describe here an improved reverse transcriptase-PCR approach that permits identification of nearly 40 different kinases in a single screening; several of these kinases are newly cloned kinases and some are novel. According to this, there are 11 receptor kinases, 9 nonreceptor kinases, and at least 7 dual kinases expressed in the xenograft tissue. The receptor kinases include erbB2, erbB3, Ret, platelet-derived growth factor receptor, sky, nyk, eph, htk, sek (eph), ddr, and tkt. The nonreceptor kinases are lck, yes, abl, arg, JakI, tyk2, and etk/bmx. Most of the dual kinases are in the mitogen-activating protein (MAP) kinase-kinase (MKK) family, which includes MKK3, MKK4, MEK5, and a novel one. As a complementary approach, we also analyzed by specific reverse transcriptase-PCR primers the expression profile of erbB/epidermal growth factor receptor family receptors in a variety of PCA specimens, cell lines, and benign prostatic hyperplasia. We found that erbB1, -2, and -3 are often coexpressed in prostate tissues, but not in erbB4. The information established here should provide a base line to study the possible growth and oncogenic signals of PCA.
A low-abundance DNA-binding protein for the DNA polymerase beta (beta-pol) promoter initiator element was purified from bovine testis. The transcriptional initiator element (Inr) of the mammalian beta-pol promoters characterized is highly conserved, and the bovine beta-pol promoter Inr has the sequence -11CAGAGGCGGCCATTGTT+6. The purified initiator element-binding protein (Inr-BP) binds with high affinity to an oligonucleotide corresponding to the beta-pol promoter Inr (Kd = 5 pM), and increasing ionic strength decreases stability of the protein-DNA complex. Mutational analysis of the Inr shows that the purified Inr-BP binds with sequence specificity to the sequence CCAT at -2 to +2 of the Inr, but that seven residues on the 5' side and three residues on the 3' side of the CCAT sequence are required also. Using an in vitro transcription assay with HeLa cell nuclear extract, we find that the endogenous Inr-BP is required for transcriptional activity of the beta-pol promoter; addition of purified Inr-BP restores activity to the nuclear extract depleted in Inr-BP by affinity chromatography. These results, based upon the sequence specificity for DNA binding, indicate that Inr-BP is a YY1-like protein and suggest that it is a required transcription factor in beta-pol gene expression.
The Bel-1 transcriptional transactivator encoded by human foamy virus (HFV) can efficiently activate gene expression directed by both the HFV long terminal repeat (LTR) and internal (Int) promoter elements. By DNA footprinting and gel retardation analysis, we demonstrate that Bel-1 can specifically bind to discrete sites in both the LTR and Int promoter elements in vitro. However, transactivation of the HFV LTR by Bel-1 was observed to require not only the promoter-proximal Bel-1 binding site identified in vitro but also additional promoter-distal sequences. These data suggest that Bel-1 binding is necessary but not sufficient for efficient transactivation of Bel-1-responsive promoters in mammalian cells and therefore raise the possibility that Bel-1 function may require the action of a cellular DNA binding protein(s). Importantly, these data demonstrate that Bel-1 is unique among retroviral regulatory proteins in being a sequence-specific DNA binding protein.
To demonstrate the antimutagenic effect of fermented milk in the human intestine, fecal mutagenicity and bacterial composition of six healthy subjects consuming their regular diet were investigated before and during the administration of milk fermented with Lactobacillus acidophilus LA-2. The administration of the fermented milk caused a remarkable decrease (71.9% on the average; range of 19.4 to 90.6%) in fecal mutagenicity compared with that before the administration; Lactobacillus spp. and Bifidobacterium spp. population increased in the feces of all subjects. The suppression of fecal mutagenicity appeared to be due to the change in fecal microflora caused by the presence of strain LA-2 in the human intestine.
Rapid turnover of nonsense-containing mRNAs in the yeast Saccharomyces cerevisiae is dependent on the products of the UPF1 (Upf1p), NMD2/UPF2 (Nmd2p) and UPF3 (Upf3p) genes. Mutations in each of these genes lead to the selective stabilization of mRNAs containing early nonsense mutations without affecting the decay rates of most other mRNAs. NMD2 was recently identified in a two-hybrid screen as a gene that encodes a Upf1p-interacting protein. To identify the amino acids essential to this interaction, we used two-hybrid analysis as well as missense, nonsense, and deletion mutants of NMD2, and mapped the Upf1p-interacting domain of Nmd2p to a 157-amino acid segment at its C-terminus. Mutations in this domain that disrupt interaction with Upf1p also disrupt nonsense-mediated mRNA decay. A dominant-negative deletion allele of NMD2 identified previously includes the Upf1p-interacting domain. However, mutations in the Upf1p-interacting domain do not affect dominant-negative inhibition of mRNA decay caused by this allele, suggesting interaction with yet another factor. These results, and the observation that deletion of a putative nuclear localization signal and a putative transmembrane domain also inactivate nonsense-mediated mRNA decay, suggest that Nmd2p may contain as many as four important functional domains.
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The core promoter of the human DNA polymerase beta (beta Pol)-encoding gene (POL beta) is regulated through cis-elements for the ATF/CREB protein(s), and GC box-binding and initiation-site-binding proteins. The mechanism of promoter regulation has been studied using a nuclear extract transcription system from HeLa cells [Narayan et al., J. Biol. Chem. 269 (1994) 12755-12763]. To study the homologous promoter (ppol beta) in a bovine system, we cloned and characterized the 5'-flanking region of the bovine gene (pol beta). A 15.3-kb fragment of bovine genomic DNA containing the first two exons and 11 kb of 5'-flanking region was isolated from a testis library in bacteriophage lambda EMBL3. S1 nuclease mapping and primer extension analysis of the 5'-end of the pol beta mRNA identified the major transcription start point (tsp), which is located 142-bp 5' of the translational start codon. In transient expression assays using a bovine cell line, analysis of various 5'-deletion mutants demonstrated that a fragment of only 91-bp 5' of the tsp had promoter activity similar to that of a 1.37-kb fragment, so that cis-elements for basal transcription are located within this approx. 100-bp core promoter, as in the human promoter (pPOL beta). Comparison of the core promoters from the bovine and human genes revealed striking similarity, including an almost precise match of the tsp, the ATF/CREB-binding and Sp1-binding sites, and the spacing separating them.
Rapid turnover of nonsense-containing mRNAs in yeast in dependent on the product of the UPF1 gene (Upf1p). Mutations in UPF1 lead to the selective stabilization of mRNAs containing early nonsense mutations without affecting the decay rates of most other mRNAs. To identify other integral components of this decay pathway, we have employed a two-hybrid screen, seeking those cellular factors that specifically interact with Upf1p. Screening of yeast genomic libraries identified six genes encoding potential Upf1p-interacting proteins. These include four previously uncharacterized genes, NMD1-4 (nonsense-mediated mRNA decay), DBP2, a gene encoding a putative RNA helicase with homology to mammalian p68 RNA helicase, and SNP1, a gene encoding a U1 snRNP 70-kD protein homolog. In this paper we report the identification and characterization of NMD2, a yeast gene that encodes a specific Upf1p-interacting protein. Disruption of NMD2 yields a nonsense-mediated mRNA decay phenotype identical to that obtained in UPF1-deletion strains, indicating that the NMD2 gene product (Nmd2p) is a new factor in the nonsense-mediated mRNA decay pathway. Deletion analysis demonstrated that the acidic carboxyl terminus of Nmd2p constituted the Upf1p-interacting domain. High-level expression of a fragment of Nmd2p containing this domain had a dominant-negative effect on nonsense-mediated mRNA decay when the protein was localized the cytoplasm but not when it was localized to the nucleus, indicating that this decay pathway has a cytoplasmic component. The association of a dominant-negative phenotype with a gene fragment identified in a two-hybrid screen suggests a generalized approach to confirming the function of genes identified in such screens.
Interstitial cystitis (IC) patients present with irritative and painful bladder symptoms and are diagnosed clinically by their symptoms, negative urine cultures, absence of other diseases, and cytoscopic findings of glomerulations and/or ulcers. The histological evaluation usually is described as nonspecific chronic inflammation. Although numerous theories of pathogenesis have been proposed, the etiology of IC is unknown. The hypothesized causes of IC include infectious, lymphovascular obstruction and neurogenic, endocrinologic, psychoneurotic, inflammatory (especially mast cells), and autoimmune pathologies. In this Review we discuss the evidence supporting a role for autoimmunity in IC and link the mast cell to the expression of the disease. Moreover, we discuss newly developed animal models that may provide insight into the etiology of IC.
We describe a clinical syndrome of delayed dystonia in children subsequent to initial gastrointestinal symptoms and acute noninflammatory encephalopathy. The syndrome was caused by the ingestion of mildewed sugarcane containing the Arthrinium-produced mycotoxin, 3-nitropropionic acid (3-NPA). In the severely affected patients, intoxication usually was heralded by coma, with dystonia appearing 7 to 40 days after recovery from the coma. The dystonia was manifested as choreoathetosis, torsion spasms, or painful paroxysmal spasms of the extremities and was neither progressive nor reversible. CTs of the dystonic patients consistently showed bilateral hypodensities in the lenticular nuclei. The pathogenesis of the selective lenticular lesions induced by 3-NPA is not yet clear.
Two cases of androgen-secreting ovary tumor were reported. patients' chief complaints were menoxemia and hirsutism; clitorism was found by physical examination. Their serum testosterone (T) were high (10.2-6.7nmol/L) and could not be suppressed to normal range by middle-dose dexamethasone inhibiting test. ACTH stimulating test could not stimulate the high serum T to raise futher, but HCG stimulating test could increase serum T to higher level. Pelvic examination, type B ultrasonic and CT scan confirmed a mass on one of the ovaries. Sertoli-Leydig cell tumor and gynandroblastoma were proved respectively by pathology. After removing the tumor, their serum T were returned to normal level.
Water deprivation test was done in 44 healthy elderly persons, 26 were male, and 18 were female. They were deprived of the intake of water for 25 hours. The results showed that the maximal renal concentration function both in the elderly males and females was 887 +/- 91 mmol/L and 888 +/- 127 mmol/L respectively. The renal excretion of waste products in 24 hours both in the elderly males and females was 815 + 170 mmol/d and 620 + 132 mmol/d respectively. On the basis of point estimation, the minimal essential urine volume per day in the elderly males and females was 926 ml/d and 708 ml/d respectively, if the daily urine volume of the elderly is less than this level, then, the metabolic products generated per day can not be excreted by the kidney, and it would result in disorders of internal environment. Therefore, the oliguric standard in elderly males and females must be less than 926 ml/d and 708 ml per day respectively.
The long-term propagation of primary human prostate cancer (PCA) in vivo or in vitro has been rare. Most such PCAs are phenotypically different from most PCAs in humans; i.e., they make little prostate specific antigen and respond little, if at all, to androgen deprivation. A serially transplantable, primary human PCA, designated CWR22, exhibits a clonal cytogenetic aberration, causes high elevations of prostate specific antigen in the peripheral blood of nude mice, and is unusually responsive to androgen deprivation as compared with other xenografts. Studies of mRNA from CWR22 have demonstrated the expression of prostate specific antigen and the epidermal growth factor receptor family including erbB1/epidermal growth factor receptor, erbB2/neu, and erbB3, but not erbB4. A ligand for these receptors, the neu differentiation factor, is also expressed.