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Biomedical subjects

Y Gao

Publications and source records attributed to Y Gao.

At least 415 records · Page 23Linked to original sources
PubMed1995

[Studies on diagnosis for occupationally chronic toxic hepatopathy].

Data from 10-to-17-year periodical physical examinations for 10,858 employees exposed to hepatotoxic chemicals were sorted out and analyzed, and 1,514 cases of suspected chronic toxic hepatopathy were detected. Causes of under-recognition of those were: (1) liver function tests now available being not sensitive enough; (2) limitations of conventional methods for diagnosis of hepatopathy by excluding other disorders; and (3) lack of diagnostic criteria for it. In the light of existing problems, the following diagnostic procedures were applied in the studies: (1) analyzing data dynamically to understand when and to what extent the liver damaged during their work; (2) exploring several more sensitive liver function tests to be used in the diagnosis, and (3) incorporating industrial hygienic files into clinical data to get preliminary diagnosis for it, and then to differentiate from other disorders and to establish a definite conclusion. With these procedures, diagnosis of occupationally chronic toxic hepatopathy was established in 1,035 cases of 1,514 suspected ones.

Benzamides↗
PubMed1995

[National notification of incidence of chronic occupational poisoning during 1984-1993].

Incidence and distribution of chronic occupational poisoning caused by toxic chemicals during 1984 to 1993 throughout the country were summarized and analyzed. Totally, 28,901 cases of chronic occupational poisoning were notified during this period. Lead, benzene and trinitrotoluene were three major toxic chemicals which caused poisoning, with chronic lead poisoning listed the first place, accounting for 47.5% of the total cases. Most of the cases distributed in Laioning, Hunan and Jiangsu Provinces, and 75.4% of the cases occurred in machinery, chemical, metallurgical, non-ferrous, light industries, etc. Incidence of poisoning presented a decreased trend during the past 10 years and the reason of it was described in the paper. The authors indicated that quality assurance in notification of occupational diseases depended on regular implementation of the work in prevention and treatment of occupational diseases.

Benzene↗
PubMed1995

[Quantitative study of a SEM image processing system on the absorptive mesothelium of the diaphragmatic peritoneum].

SEM and a medical image processing system attached to SEM were used to study the peritoneal mesothelium on mice diaphragm. The absorptive mesothelium was first reported owing to its function and morphology. The absorptivity of diaphragmatic peritoneum was surveyed by the measurement of the area of the absorptive mesothelium. The arrangement of the absorptive mesothelium on diaphragmatic peritoneum was block-like with abnormal distribution, and the maximum and minimum areas of the block were 1153 microns 2 and 66 microns 2. But the absorptive mesothelium on left and right half diaphragm were normally distributed. The average areas of the absorptive mesothelium on all diaphragm, left half diaphragm and right half diaphragm were 432.6 microns 2, 270.5 microns 2 and 512.0 microns 2 respectively. The distributive law of the absorptive mesothelium was costal portion > sternum portion > vertebral column portion. The average absorptivity of all diaphragmatic peritoneum was 29.2%, but that of left and right half diaphragmatic peritoneum were 17.4% and 32.9% respectively.

Absorption↗
PubMed1995

[The value of CT and MRI in differentiating malignant nodule from tuberculoma].

Correlative study of CT, MRI and pathology was done on 121 cases with solitary pulmonary nodule less than 3 cm in diameter, including 97 malignant nodules and 24 tuberculoma. On CT, the main morphological characteristics of the malignant nodules is lobucation, spiculation, vessele involvement, heterogeneous density, and vacuole sign and air bronchogram, and that of the tuberculoma, the smooth margin, homogeneous density, calcification. On the other hand, the relative signal intensity of these pulmonary nodules were evaluated on T1, T2 weighted image. Our prelminary results indicated that though MRI is inferior to CT in the assessment of the margin and internal feature of the nodule, it can provide further information in differentiating between malignant nodule and tuberculoma.

Adenocarcinoma↗
PubMed1995

[Analysis of the results of fibrobronchoscopy relevant to x-ray examination in 138 cases with hemoptysis].

Only 90 abnormal cases of the chest X-ray examination were found among 138 patients with hemoptysis. However the main results of the fibrobronchoscopy for 138 cases were: chronic bronchitis and pulmonary inflammation 59 cases (42.8%), bronchogenic carcinoma 41 cases (29.7%), tuberculosis 10 cases (7.2%) and others 28 cases (20.3%). Authors conclude that fibrobronchoscopy can clarify the nature of lesions and the cause of hemoptysis on the basis of chest X-ray examination.

Adenocarcinoma↗
PubMed1995

[Prediction of retinoblastoma: linkage analysis of families with hereditary retinoblastoma by using polymorphic sites within the Rb gene].

Retinoblastoma (Rb) is one of the most common intraocular tumors in childhood. 40% of the cases are hereditary in nature. 10% are due to the transmission of a germline mutation from an affected parent, and 30% are due to new germ cell mutation. In the hereditary form, the mutation is inherited via a germ cell; therefore, the mutant gene is present in all somatic cells. The segregations of four polymorphic sites within the Rb gene were analyzed in six families with hereditary retinoblastoma. Two families were informed with probe p123M1.8, three were informed with probe p68RS2.0 and one was informed with PCR amplification of XbaI site; all six families were informed with PCR amplification of intragenic VNTR site RB1.20. Our results showed that linkage analysis of families with hereditary retinoblastoma by using intrageneic polymorphic sites could be applied to detect carriers and for prenatal diagnosis in families with hereditary retinoblastoma.

Base Sequence↗
PubMed1995

[Sutureless incision for intraocular lens implantation].

The technique of incisional construction, the degree of automatic closure and the results of postoperative induced corneal astigmatism were reported in a series of 50 eyes with 5.5 mm sutureless incision for 6.0 mm PMMA intraocular lens (IOL) implantation. The patients ages ranged from 8 to 72 years. In this study, I-stage implantation was performed on 13 eyes and II-stage implantation, on 37 eyes. In this group, 19 aphakic eyes had had the histories of penetrating injuries and 1 to 3 times of operations. 15 aphakic eyes had had histories of senile cataract extractions, 14 eyes were congenital cataracts and another 2 eyes were other kinds. The surgical maneuvers included an external scleral frown incision 5 mm in chord length, a scleral-tunnel dissection and a corneal internal valve incision into the corneal limbus for 1 mm and keeping horizontally 6.0 mm in width. All the implantations were smooth, incisions closed watertightly without leakage or shallow anterior chamber. The means value of induced corneal astigmatism was -0.16(0.71)D with a range of +1.00 to -1.50 D. The complications were less than that of sutured operations. The results suggest that sutureless incision be safe, reliable, self-closed tightly, less induced astigmatism and could be a better kind of incision for standard IOL implantation.

Adolescent↗
PubMed1995

[The relationship between diabetic retinopathy and cataract extraction with intraocular lens implantation in diabetics].

47 diabetics (71 eyes) having undergone cataract extraction with intraocular lens (IOL) implantation were examined and followed up. The results show that there is significant difference in the last post-operative visual acuities between the diabetic group and non-diabetic group (P < 0.01). The main cause affecting the post-operative visual acuities of the diabetics is diabetic proliferative retinopathy (P < 0.001). There is no significant difference in the post-operative visual acuities between diabetic group with or without simple diabetic retinopathy and non-diabetic group (P > 0.05). The intra- and post-operative complications in the diabetic and non-diabetic group were also investigated and there was no significant difference. IOL implantation should be guarded for diabetics with proliferative retinopathy especially when complicated with maculopathy.

Aged↗
PubMed1995

[Non-radioactive detection of dinucleotide repeat polymorphisms and its application to genetic diagnosis].

We have developed a rapid and non-radioactive procedure for detecting dinucleotide repeat polymorphisms. Specific primers flanking the repeats were used in the polymerase chain reaction (PCR). The generated allelic fragments were resolved by thin-layer denaturing polyacrylamide gel electrophoresis and visualized by improved silver staining. This method is simple, fast and without labelling of PCR products. Resolution of 1 bp can be easily obtained. It can also be used in multiplex PCR analysis of (CA)n loci. This method will be a valuable tool for linkage analysis and DNA diagnosis as demonstrated by its successful application to the CA dinucleotide repeat haplotying of a DMD family.

Base Sequence↗
PubMed1995

The inductive effect of bone morphogenetic protein (BMP) on human periodontal fibroblast-like cells in vitro.

Bone morphogenetic protein (BMP) has the capability of 1) inducing bone formation in non-bone tissue such as muscle, 2) promoting proliferation and differentiation of human dental pulpal cells, and 3) inducing early formation of both osteodentin and regular tubular dentin. In addition, when BMP is implanted in periodontal defects, it stimulates regeneration of periodontal tissues. In the present study, we sought to explore the mechanisms by which BMP induces these effects, using immunohistochemical methods to investigate periodontal fibroblast-like cells in vitro. Cellular production of fibronectin, endogenous BMP and alkaline phosphatase were measured using image analysis of immunohistochemical reactivity. Periodontal fibroblast-like cells incubated with exogenous BMP showed decreased alkaline phosphatase activity, unchanged fibronectin production, but increased expression of endogenous BMP compared with control specimens incubated without BMP. These data suggest that regenerative as well as inductive effects of BMP on undifferentiated periodontal mesenchymal cells may be mediated through its ability to modulate cellular expression of these substances.

Alkaline Phosphatase↗
PubMed1995

Induction of reparative dentin formation in dogs by bovine bone morphogenetic protein bound to ceramic dentin.

Bone morphogenetic protein (BMP) refers to a group of bone-inducing growth factors used to enhance experimental osseous repair. Previous studies have indicated that BMP promotes the proliferation and differentiation of fibroblasts from human dental pulp both in vitro and in vivo. Furthermore, when BMP is used as a pulp capping agent, it has ability to induce the formation of both osteodentin and tubular dentin. In this study, we sought to explore whether or not BMP, complexed to ceramic dentin (BMP/CD), would constitute a more effective pulp capping agent than BMP alone. Experimental pulp exposures were created in dogs, and BMP/CD was placed on the surface of the exposed dental pulp. The inductive effect of such stimulation on reparative dentin formation was observed morphologically. Results showed that two weeks after exposure, some osteodentinal matrix was formed in the space surrounding the implanted BMP/CD particles while the remainder of the space was occupied by proliferating fibroblasts. At 4 weeks postoperatively, the dential bridge was complete. When ceramic dentin without BMP was used, there was minimal bone-like matrix formed even at 4 weeks postoperatively. These results suggest that the BMP/CD complex is effective as a stimulant of reparative dentin formation and shows potential as a therapeutically useful pulp-capping agent in a clinical setting.

Animals↗
PubMed1994

Synthesis, ligand binding, and QSAR (CoMFA and classical) study of 3 beta-(3'-substituted phenyl)-, 3 beta-(4'-substituted phenyl)-, and 3 beta-(3',4'-disubstituted phenyl)tropane-2 beta-carboxylic acid methyl esters.

Several new 3 beta-(4'-substituted phenyl)-, 3-beta-(3'-substituted phenyl)-, and 3 beta-(3',4'-disubstituted phenyl)tropane-2 beta-carboxylic acid methyl esters were prepared and assayed for inhibition of [3H]WIN 35,428 binding to the dopamine transporter. The 3 beta-(3',4'-dichloro) and 3 beta-(4'-chloro-3'-methyl) analogues (2w and 2y; RTI-111 and RTI-112, respectively) with IC50 values of 0.79 and 0.81 nM showed the highest affinity. The contributions of quantitative structure-activity relationship (QSAR) models derived from the classical and comparative molecular field analysis (CoMFA) approaches to rational drug design were examined. CoMFA models were derived using steric and electrostatic potentials with SYBYL default values while the classical models were derived from pi and MR parameters. Using a 12-compound training set, both models were used for predicting the binding affinity of compounds both inside and outside the training set. The CoMFA study provided new insight into the steric and electrostatic factors influencing binding to the DA transporter and provided additional support for our original finding that CoMFA is useful in predicting and designing new compounds for study. The classical QSAR models, which were easier to obtain, suggest that the distribution property (pi) of the compounds is an important factor. Overall, the SAR, CoMFA, and conventional QSAR studies elaborated some features of the cocaine binding site pharmacophore and provided useful predictive information.

Animals↗
PubMed1994

An adrenomedullin fragment retains the systemic vasodepressor activity of rat adrenomedullin.

The present study was undertaken to investigate the effects of human adrenomedullin, a newly discovered peptide present in normal human plasma, as well as a fragment of adrenomedullin, on systemic hemodynamics in the anesthetized rat. Intravenous (i.v.) bolus injections of rat adrenomedullin, rat adrenomedullin-(11-50), human adrenomedullin-(13-52) decreased mean systemic arterial pressure in a dose-dependent manner. Since rat adrenomedullin and human adrenomedullin did not decrease cardiac output, the decreases in systemic arterial pressure reflect dose-dependent reductions in systemic vascular resistance. The systemic vasodepressor responses to similar doses of the adrenomedullin fragments studied and to their respective parent adrenomedullin peptides were similar. The present data demonstrate that the entire adrenomedullin molecule is not required for full systemic vasodilator activity in vivo suggesting that rat adrenomedullin-(11-50) or a structurally similar peptide, if formed endogenously, could mediate the hemodynamic properties of adrenomedullin in vivo. Since rat adrenomedullin had significantly greater systemic vasodilator activity than human adrenomedullin at similar doses in the rat, the present data suggest that adrenomedullin has greater systemic vasodilator activity in its native species and that limited changes in the peptide's sequence confer markedly different vascular activity in vivo.

Adrenomedullin↗
PubMed1994

Structural and functional divergences of the columbid annexin I-encoding cp37 and cp35 genes.

Annexin-I proteins in the pigeon are encoded by two genes. One encodes a constitutively expressed cp37 protein, and the other encodes a major prolactin (PRL)-regulated protein (cp35). As one goal in understanding the differential regulation of these genes, we have determined a 10.8-kb genomic sequence of the cp37 gene containing 1.3 kb of 5'-flanking region and the first six exons. The promoters of cp37 and cp35 are 84% identical over the first 210 bp upstream from the transcription start point (tsp). Cell-free transcription demonstrated that this -210 region of cp37 contained an active promoter. Two nuclear protein-binding sites, which may be involved in the constitutive expression of cp37, were localized between -205 and -106 bp. PRL-dependent transcription factors bind to the -73 to -8 region of cp35, but not cp37. The sequences of these regions contain six single-base differences, which may be responsible for the genes' divergent transcriptional regulation. The 5'-flanking regions of cp37 and cp35 were cloned into a reporter plasmid and transfected into T-47D cells. Transient transfection analysis revealed that the constructs containing cp35 5'-flanking regions were inactive, whereas the cp37 promoter was constitutively active and contained both positive and negative cis-acting sequences.

Amino Acid Sequence↗