[International expert consensus on gene therapy for hereditary hearing loss: based on clinical trials].
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Journal Article↗
Biomedical subjects
S Han
Publications and source records attributed to S Han.
Specific identification of collagens and their fragments by clostridial and anti-collagenase antibody.
A method specific for identification of collagens irrespective of type, species, or tissue origin, and of their derived fragments of molecular weight more than 10,000, is described. The method is based on the low-temperature affinity between clostridial collagenase and almost all types of collagens as well as on the affinity between collagenase and its antibodies. Various collagens or fragments derived from them by treatment with CNBr were separated by SDS-PAGE and immobilized onto a nitrocellulose membrane by a slot-blot technique or electrotransfer. Following binding of clostridial collagenase to a collagen or its fragments at 0 degrees C, the collagen-collagenase complex was fixed with glutaraldehyde. The complex was then allowed to bind anti-collagenase antibody at room temperature. The new complex was subsequently treated with 125I-labeled donkey anti-rabbit IgG and visualized as an autoradiogram. Under the conditions of low temperature used, the collagenase binds to collagens without causing their digestion. This procedure is specific for detection of soluble collagens as well as of insoluble collagens converted to fragments by treatment with CNBr. The method is uniquely suited for detection of fragments of tissue collagens. Also, it may serve as a prototype for methods for detection of other specific polymeric substances.
Amino Acid Sequence↗
[Characteristics of monoclonal antibodies against chorionic gonadotropin receptor].
We reported the production of monoclonal antibodies (McAb) against chorionic gonadotropin (CG) receptor by fusing spleen cells of BALB/c mice immunized with purified pseudomonas maltophilia CG receptor with mouse myeloma line (SP 2/0). Four hybridoma cell lines secreting CG receptor McAbs were obtained (ED 490, DG 390, AB 890, GE 590). GE 590 is IgG 1; ED 490, DG 390, AB 890 are IgG2b. I125-HCG and ED 490, DG 390. AB 890 recognized CG receptor different antigenic determinant. Increased concentrations of GE 590 were in inverse proportion to the amount of I125-HCG binding to human ovarian tissues showing that normal ovarian tissues and ovarian malignant tumors have different HCG receptor antigenic determinant. This study indicated that these McAbs may be useful in studying the structure of CG receptor and in providing a valuable evidence for early diagnosis and treatment of ovarian malignant tumors.
Adenocarcinoma, Mucinous↗
[Study of the estrogen receptor and progesterone receptor in human cervical carcinoma].
Three hundred and twelve different cervical specimens have been tested for estrogen (ER) and progesterone receptor (PR) content with dextran-coated charcoal method (DCC). The results showed that the concentrations of ER and PR in normal cervical tissues were higher than those in malignant cervical tissues, and that the percentage of positive scores for ER and PR in cervical squamous epithelial tissues were higher than that in malignant cervical tissues. That the variances of ER and PR in cervical malignant tumors were not parallel suggested that the production or/and the mechanism of receptor action might be impaired. The percentage of positive scores for ER was not correlated with the clinical stages whereas that of PR was inversely proportional to clinical stages. That some patient with cervical cancer had high level of PR and had both ER and PR positive implied the possibility for endocrine therapy. The content and distribution of ER and PR in normal cervical tissues are consistent with the effects of sex hormone.
Carcinoma, Squamous Cell↗
Nude mouse interim host model for human parathyroid grafts. II. Alteration of MHC antigens in human PTG grafts in the nude mouse.
Human parathyroid (PTG) tissues from cadaver (C-PTG), 5-month fetus (F-PTG) and PTG adenoma (A-PTG) were transplanted into the kidney subcapsular areas of Balb/C nude mice as interim host. Dynamic changes in the amount of tissue major histocompatibility complex (MHC) antigen present within the transplantation period were observed. The results showed that during 100 days of interim hosting, no obvious changes in the expression of tissue MHC class I antigens were seen, but the expression of tissue MHC class II antigens was significantly reduced. The changes of MHC antigens in different donor human PTG tissues were compared.
Adenoma↗
Characterization of the DNF15S2 locus on human chromosome 3: identification of a gene coding for four kringle domains with homology to hepatocyte growth factor.
A human genomic DNA library was screened by using conditions of reduced stringency with a bovine cDNA probe coding for the kringle domains in prothrombin in order to isolate the human prothrombin gene. Twelve positives were identified, three of which coded for prothrombin (Degen & Davie, 1987). Phage L5 was characterized in more detail because of its strong hybridization to the cDNA probe and its unique restriction map compared to the gene coding for human prothrombin. The gene in L5 was sequenced and found to code for a kringle-containing protein. A human liver cDNA library was screened by using a genomic probe from the gene in L5. cDNAs were isolated that contained sequence identical with regions in the gene in L5. Comparison of the cDNA with the gene indicated that the gene in L5 was composed of 18 exons separated by 17 intervening sequences and is 4690 bp in length. Exons ranged in size from 36 to 242 bp in length while intervening sequences ranged from 77 to 697 bp in length. The putative protein encoded by the gene in L5 contains four kringle domains followed by a serine protease-like domain. This domain structure is identical with that found in hepatocyte growth factor (HGF), although the two proteins are only about 50% identical. On the basis of the similarity of the protein encoded by L5 and HGF, we propose that the putative L5 protein be tentatively called HGF-like protein until a function is identified. The DNA sequence of the gene and cDNA and its translated amino acid sequence were compared against GenBank and NBRF databases. Sequences homologous to DNF15S1 and DNF15S2, human DNF15S2 lung mRNA, and rat acyl-peptide hydrolase were identified in exon 17 to the 3' end of the characterized sequence for the gene. From our results, it is apparent that the gene coding for human HGF-like protein is located at the DNF15S2 locus on human chromosome 3 (3p21). The gene for acyl-peptide hydrolase is 444 bp downstream of the gene coding for HGF-like protein, but on the complementary strand. The DNF15S2 locus has been proposed to code for one or more tumor suppressor genes since this locus is deleted in DNA from small cell lung carcinoma, other lung cancers, renal cell carcinoma, and von Hippel-Lindau syndrome.
Amino Acid Sequence↗
Characterization of the mouse cDNA and gene coding for a hepatocyte growth factor-like protein: expression during development.
The cDNA and gene coding for mouse hepatocyte growth factor-like protein (HGF-like protein) were isolated and characterized. The size of the gene from the site of initiation of transcription to the polyadenylation site is 4613 bp in length and is composed of 18 exons separated by 17 intervening sequences. The exons range in size from 36 to 227 bp in length, while the intervening sequences range in size from 78 to 613 bp in length. The site of initiation of transcription was identified by primer extension analysis using total RNA isolated from mouse liver. On the basis of these results, the first exon is 146 bp in length and includes 94 bp of 5'-noncoding sequence. The sequence 5'TATGTG3' is present between 34 and 39 bp upstream of the transcription start site and could potentially be the TATA sequence found for many constitutively expressed eukaryotic genes to be the promoter for RNA polymerase II. The sequence 5'GCAAT3' at -96 to -92 may be the CCAAT sequence responsible for stimulation of transcription of some eukaryotic genes. The same sequences in the Genbank and NBRF databases were homologous to similar regions in the genes coding for both human and mouse HGF-like protein (Han et al., 1991). The acyl-peptide hydrolase gene is 410 bp downstream of the mouse HGF-like protein, but is transcribed from the complementary strand. The mouse cDNA for HGF-like protein codes for a putative protein with the same domain structure as its human homologue with four kringle domains followed by a serine protease-like domain. On the basis of the translated sequence of the cDNA, the mouse HGF-like protein would be 716 amino acids in length with a molecular weight of 80K. There are four potential N-linked carbohydrate attachment sites. The DNA and amino acid sequences of mouse HGF-like protein are compared to the human protein. Overall, the two proteins are about 80% identical with each other. In contrast to mRNA for human HGF-like protein, which is 2.4 and 3.0 kilobases in length in human liver, only the smaller species is seen in mouse and rat liver. The expression pattern of mRNA coding for HGF-like protein during development and in maternal rats was determined by Northern analysis. It is apparent that the majority of mRNA coding for HGF-like protein is expressed in liver. Messenger RNA is also expressed at a lower level in lung, adrenal, and placenta.
Amino Acid Sequence↗
Initial experience with a practical hyperfractionated accelerated radiotherapy regimen.
This paper presents early results of a trial of a three-fractions-per-day (TID) regimen that is more convenient to schedule than the Continuous Hyperfractionated Accelerated Radiotherapy (CHART) protocol currently being tested in Europe. The treatment schedule used in the CHART regimen has been modified from 36 fractions of 1.5 Gy TID in 12 days to 72 fractions of 1.1 Gy in 24 treatment days, with all fractions delivered during normal working hours. With no weekend treatments, the entire course of radiotherapy is completed in less than 5 weeks. The doses used were determined using the L-Q model, with correction for incomplete repair between fractions and for accelerated repopulation of cancer cells. Comparison with historical controls shows statistically significant improvements both in CR rates for the primary tumor and in acute toxicity, as measured by reduced treatment interruptions. L-Q model calculations predict that, compared to the highest dose achieved in previous studies without exceeding tolerance, we are able to obtain a 12% increase in bioeffect dose to the primary tumor due to accelerating the treatment. An analysis of the potential tumoricidal effectiveness of this new treatment regimen shows that it should be better than several other accelerated fractionation schedules being tested for all values of Tpot. For short Tpot times, the advantage may be as much as one log cell kill, corresponding to a 10-15% potential improvement in local control.
Aged↗
[Preparation of monoclonal antibodies against chorionic gonadotropin receptor and study of its characteristics].
We reported the production of monoclonal antibodies (McAbs) against chorionic gonadotropin hormone (CG) receptor by fusing spleen cells of BALB/c mice which had been immunized by purified bacteria (Pseudomonas maltophilia) CG receptor with mouse myeloma line SP2/0. Four hybridoma cell lines secreting CG receptor McAbs were obtained (ED490 DG390, AB890 and GE590). The titers of specific antibodies of both mice ascites and culture supernatant were 10(-2)-10(-6) and 1-10(-2) respectively, by solid phase ELISA. Double-Immunodiffusion test showed that the McAb GE590 was IgG1, and the McAbs ED490, DG390 and AB890 were IgG2b Immunoprecipitation indicated that 125I-HCG could bind the HCG receptor which had reacted with McAbs ED490, AB890 and DG390, suggesting that they may recognize the receptor with different antigenic determinant. Interaction of McAb GE590 with the receptor showed that the increased concentration of GE590 was in inverse proportion to the amount of 125I-HCG binding receptor, indicating that both the McAb and 125I-HCG could recognize a common site of receptor and that increased concentration of McAb GE590 may induce some change in conformation and structure of the receptor. Our study suggested that these McAbs may be used for studying structure of CG receptor.
Animals↗
Ferryl and hydroxy intermediates in the reaction of oxygen with reduced cytochrome c oxidase.
Cytochrome c oxidase catalyses the 4-electron reduction of dioxygen to water and translocates protons vectorially across the inner mitochondrial membrane. Proposed reaction pathways for the catalytic cycle of the O2 reduction are difficult to verify without knowing the structures of the intermediates, but we now have such information for the catalytic intermediates in the first steps of the reaction of O2 with cytochrome c oxidase from resonance Raman spectroscopy, a technique that enables iron-ligand stretching modes to be identified. Here we report on two more key intermediates: a ferryl-oxo (Fe4 = O2-) and a ferric-hydroxy (Fe3+--OH-) intermediate at the level of 3- and 4-electron reduction, respectively. We identified these intermediates by their characteristic iron-oxygen stretching frequencies (786 cm-1 for Fe4+ = O2-, and 450 cm-1 for Fe3+ -- OH-) and oxygen and deuterium isotope shifts. The oxo atom in the ferryl intermediate is hydrogen-bonded and the iron-oxygen bond in the hydroxy intermediate is anomalously weak. With the identification of the primary, ferryl and hydroxy intermediates, the predominant structures at almost all stages of O2 reduction are now known and the catalytic pathway can be described with more certainty.
Deuterium↗
Primary intermediate in the reaction of mixed-valence cytochrome c oxidase with oxygen.
The reaction of dioxygen with mixed-valence cytochrome c oxidase was followed in a rapid-mixing continuous-flow apparatus. The optical absorption difference spectrum and a kinetic analysis confirm the presence of the primary oxygen intermediate in the 0-100-microseconds time window. The resonance Raman spectrum of the iron-dioxygen stretching mode (568 cm-1) supplies evidence that the degree of electron transfer from the iron atom to the dioxygen is similar to that in oxy complexes of other heme proteins. Thus, the Fe-O2 bond does not display any unique structural features that could account for the rapid reduction of dioxygen to water. Furthermore, the frequency of the iron-dioxygen stretching mode is the same as that of the primary intermediate in the fully reduced enzyme, indicating that the oxidation state of cytochrome a plays no role in controlling the initial properties of the oxygen binding site.
Chemical Phenomena↗
Metastable intermediates in myoglobin at low pH.
Resonance Raman and optical absorption spectra of ligand-free (deoxy) myoglobin and CO-bound myoglobin (MbCO) at pH 2.6 have been measured by using continuous-flow/rapid-mixing techniques. The spectra of deoxy myoglobin at low pH within 6 ms of the pH drop demonstrate that the iron-histidine bond has been ruptured but that the heme is still five-coordinate. Comparison with data from model complexes indicates that a weak-field ligand, such as a water molecule, is coordinated at the fifth position. The Raman spectrum of MbCO at low pH has an Fe-CO stretching mode that is characteristic of a six-coordinate heme with an unhindered Fe-CO moiety. Immediately following the pH drop in this case, there is no indication that the iron-proximal histidine bond is broken. Three different structural changes are detected at low pH: (i) the iron-proximal histidine (F8) bond in ligand-free myoglobin is broken and replaced by a weak-field ligand, (ii) the distal pocket in MbCO is opened, and (iii) protein constraints on the heme group in MbCO are relaxed. Previous conclusions that the kinetics of CO-binding in hemoproteins at low pH is modified by rupturing the iron-proximal histidine bond are supported by these new results which, however, demand a more complete reevaluation of the phenomenon.
Animals↗
[The clinical use of sodium hyaluronate eyedrops as a substitute for tears].
The present paper reports on the curative effect of the 0.1% Sodium hyaluronate (Na-HA) eyedrops jointly manufactured by Guangzhou Red Cross Hospital and Guangzhou Institute of Medical & Pharmaceutical Industry. 70 cases were studied. There were kerato-conjunctivitis sicca, lagophthalmos corneal fluorescein diffuse punctate epithelial lesion caused by contact lens, and keratitis punctata superficialis. The results showed effective treatment which occupied 95.7%. In the discussion, the authors point out that Na-HA has the same stagnatisity and elasticity as biotears because of its adhesion to the corneal epithelium. Moreover, it has the water-retaining microsponge action similar to that of mucopolysaccharide. Hence, Na-HA has protective effects on corneal epithelium. Finally, the authors conclude that Na-HA eyedrop is so far the most ideal substitute for tears and superior to other artificial tears.
Adult↗
Marginal gap formation in the composite resin/glass ionomer cement Class V restoration.
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Composite Resins↗
Calcium homeostasis after parathyroidectomy in normal and shocked states.
The natural history of parathyroidectomy was studied for 75 weeks in two dogs. After parathyroidectomy, the dogs required intravenous and intramuscular calcium supplementation for 1 week. Despite calcium supplementation, in 2 weeks the ionized calcium (Ca++) level fell from 4.67 mg/dl to 2.39 mg/dl. The Ca++ level rose to 4.25 mg/dl by 7 weeks after which the intramuscular calcium supplement was gradually weaned so that no calcium was given after 20 weeks. The Ca++ level stabilized at 3.15 to 3.25 mg/dl after 20 weeks. Postoperative parathormone (PTH) levels remained low. The response to hemorrhagic shock in these two calcium-independent dogs was compared with that seen in two calcium-dependent dogs 4 weeks after parathyroidectomy and to that seen in two euparathyroid dogs. Shock caused a sharp decrease in Ca++ in all animals that had parathyroid ectomy. Prostaglandin E2 (PGE2) was elevated preoperatively in these dogs and fell markedly during shock. Ca++ remained normal and PGE2 increased slightly after shock in the euparathyroid dogs. Cardiac output rose with resuscitation in the euparathyroid dogs but remained constant in the calcium-dependent dogs and increased slightly in the calcium independent parathyroidectomized animals. PTH levels were low in the parathyroidectomy groups and did not react to shock. PTH increased markedly after resuscitation in the euparathyroid dogs, suggesting its role as an acute-phase hormone. All levels returned to baseline levels within 3 days after shock. Adaptation to hypocalcemia occurs in parathyroidectomized dogs and involves PGE2 as well as other factors. Hemorrhagic shock exceeds this compensatory response which in euparathyroid dogs involves active PTH release in response to hypocalcemia.
Animals↗
Neurospora crassa and S1 nuclease cleavage in hsp 83 gene chromatin.
We have examined the distribution of Neurospora crassa and S1 nuclease cleavage products in the chromatin of the hsp 83 heat shock gene from the Drosophila melanogaster cytogenetic locus 63 BC. Both of these nucleases generate double strand breaks in chromatin at specific sites close to the 5' end of the hsp 83 gene. With N. crassa nuclease we observe one major 5' fragment which is derived from nuclease cleavage in a DNA segment mapping approximately 120 base-pairs from the beginning of the transcription unit. With S1 nuclease we observe one major fragment which overlaps the transcription start site. In addition to the major hypersensitive sites at the beginning of the gene, the hsp 83 transcription unit is also sensitive to attack by these nucleases both before and after heat shock; however, the yield of cleavage products from within the gene is considerably greater after heat induction.
Animals↗
Identification and quantitation of O-phosphoserine in human plasma fibronectin.
O-Phosphoserine was positively identified as the phosphorylated moiety in human plasma fibronectin by 31P-NMR of intact peptides. These data correlated completely with chemical analyses which demonstrated the presence of O-phosphoserine at a concentration of 2 residues/molecule. Neither O-phosphothreonine nor O-phosphotyrosine was detected in partial acid and partial alkaline hydrolysates, respectively.
Fibronectins↗
Chromatin structure of the 87A7 heat-shock locus during heat induction and recovery from heat shock.
We have examined the chromatin organization of the 87A7 heat-shock locus (which contains two hsp 70 genes transcribed in opposite orientation) as a function of the time of heat induction and during the course of recovery from heat shock. Our studies show that both induction and recovery from heat shock are accompanied by highly specific alterations in the nucleoprotein structure of this locus. Moreover, these changes parallel the transcriptional activity of the hsp 70 heat-shock genes. We have also examined the effect of inhibitors of transcription and translation. Cycloheximide, an inhibitor of translation, blocks both the attenuation of the heat-shock response (which occurs after a long-term incubation at elevated temperatures) and the re-establishment of the pre-induced chromatin organization of the locus during recovery from heat shock. Actinomycin D, an inhibitor of transcription, prevents some but not all of the alterations in chromatin structure which normally accompany heat induction.
Animals↗