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Biomedical subjects

Y Hu

Publications and source records attributed to Y Hu.

At least 559 records · Page 31Linked to original sources
PubMed1995

[Effects of leech and ground beetle powder on hemorheology and blood lipid of ischemic stroke].

In order to improve blood supply for the brain, restore the functions of the cerebral cells and the limbs, and increas the curative rate, the leech (Hirudo nipponica and ground beetle Eupolyphage sinensis), powder (LGBP) to the patients according to the principle of promoting the blood circulation to remove the stasis was administered, and the clinical observation and experimental study was conducted. Its effects were compared with those of Western medicines. The results showed that after medication of LGBP, the blood flow of brain significantly increased, the hypoxia was improved, blood viscosity and blood lipid were lowered and thrombosis was inhibited in vitro or in vivo. No toxic side-effects caused by LGBP was found.

Adult↗
PubMed1995

[Rectal administration of ash bark].

A TLC-densitometric method was applied to determine aesculin in rabbit blood. The best way for ash bark rectal administration was found by orthogonal design [L4(2(3))]. The two routes of administration (per rectal, P.O.) were compared by bioavailabilities and the result indicated that per rectal was better than P.O. Modified isolated rectum-bag method was applied successfully to finding the best way for rectal administration of ash bark.

Administration, Rectal↗
PubMed1995

[A real-time analysis of 133 normal lens images by a computer].

According to the theory that the light scattering of the lens is correlated with the lens density, we designed a computerized system for the real-time analysis of the lens image. By measurement of the gray scale value of the lens optical section, the lens density is measured objectively and numerically. With the help of the system, 133 normal lens images were investigated. From the analysis of various age groups, we found that the grey scale values of the anterior cortex, posterior cortex and nucleus increase with the increase of age (P < 0.01), the grey scale values of the anterior and posterior cortex are significantly higher than the value of the nucleus (P < 0.05), but there is no significant difference between the values of the anterior and posterior cortex (P > 0.05), and there is also no significant difference in the comparisons of the grey scale values of the respective corresponding lens areas between the male and female.

Adolescent↗
PubMed1995

[Effect of dietary and/or exercise intervention on incidence of diabetes in 530 subjects with impaired glucose tolerance from 1986-1992].

577 subjects with impaired glucose tolerance (IGT) aged from 25 to 74 were identified in Daqing in 1986. They were stratified according to BMI > or = 25 (352 cases) and BMI < 25 (225 cases) and subjects in each BMI group were randomly assigned to four groups: control, diet, exercise and diet plus exercise intervention groups (each group had similar age, BMI, fasting and 2-hour plasma glucose level). A six-year follow up study indicated that incidence of diabetes per 100-person-year was 15.7, 10.0, 8.3 and 9.6 in control, diet, exercise and diet plus exercise groups respectively. Proportional hazards regression analysis controlling for differences in baseline factors (age, sex, BMI and plasma glucose) showed that diet and/or exercise intervention were inversely related to the incidence of diabetes. The better the actual intervention, the less the incidence of diabetes. Therefore, the results strongly indicate that diet and/or exercise intervention treatment are effective methods to reduce the incidence of diabetes.

Adult↗
PubMed1995

[Stability of refraction in post-operative two years of radial keratotomy].

In order to study the stability of the refraction after radial keratotomy, we took 123 cases (245) eyes who all had continuous follow-up records in two postoperative years to observe their dynamic changes. The mean preoperative spherical equivalent refraction was -6.74 D, and the mean keratometry was 44.32 D. The mean spherical equivalent refraction which was reduced after the surgery at one week, one month, three months, six months, one year and two years was 6.77 D, 5.74 D, 5.14 D, 5.09 D, 5.14 D and 5.27 D, respectively. The decrease of the spherical equivalent refraction in our cases showed that the maximum range of myopic drop was at one week after surgery. But the myopia obviously rose again in the postoperative three months. Statistical analyses showed that the differences between one week and one month and between one week and three months after surgery were significant (P < 0.01). There were little changes in the course of postoperative six months to two years, being not significant statistically (P > 0.05).

Follow-Up Studies↗
PubMed1995

Findings of cholangiopancreatography in pseudotumorous pancreatitis.

The cholangiopancreatographic findings in 22 patients with pseudotumorous pancreatitis (PTP) were evaluated on the basis of endoscopic retrograde cholangiopancreatography (ERCP) and percutaneous transhepatic cholangiography (PTC). All patients were found with a focal mass in the pancreas based on the findings of ultrasound and/or CT. However, only one patient had been diagnosed correctly as suffering from chronic pancreatitis by ERCP. Normal pancreatic duct was found in 4 patients. There were five patients having abnormal pancreatic ducts, but findings of ERCP could not provide definite diagnosis. In the remaining 12 patients the abnormalities of pancreatic and/or bile ducts were strikingly similar to those found in pancreatic carcinoma. Double duct sign was also seen in one patient. All these 12 patients were incorrectly diagnosed as having pancreatic carcinoma. It is concluded that ERCP/PTC has little value in detecting PTP.

Adult↗
PubMed1995

Induction of osteogenesis by bovine platelet transforming growth factor-beta (TGF-beta) in adult mouse femur.

TGF-beta has been shown to be one of the most important regulators in chondrogenesis and osteogenesis. Daily subperiosteal injection of TGF-beta, which was extracted and purified from bovine platelets, into adult mouse femur resulted in proliferation and differentiation of the mesenchymal cells, chondrogenesis, and endochondral osteogenesis. After cessation of the injection, the endochondral ossification occurred widely, resulting in replacement of the cartilage with new bone. These phenomena demonstrate that exogenous TGF-beta stimulates mesenchymal proliferation and differentiation that occur in early fracture healing and suggest the possibility of clinical application of TGF-beta for fracture repair and bone transplantation.

Animals↗
PubMed1995

[153Sm-EDTMP for moderate and severe bone cancer pain].

One hundred and thirty-six patients with bone cancer pain were treated with 153Sm-EDTMP (ethylenediamine-tetramethylene phosphonic acid). Pain free was noted in 49 cases (36%, 49/136) and pain relief in 77 cases (56.6%, 77/136), the total relief rate being 92.6% (126/136). The data from 76 patients with moderate and severe pain showed there were no significant relationships between the patients' age, the dose of 153Sm-EDTMP and the analgesic effects (P > 0.05). The pain relief observed in the patients with chest pain (ribs metastases) was earlier than that in other groups (P < 0.05). We didn't find any clinical side-effects, so 153Sm-EDTMP is safe for use.

Adult↗
PubMed1995

[Characterization of human coagulation factor IX cDNA expressed in cultured cells and in transgenic mice].

Two recombinant genes containing human coagulation factor IX cDNA driven by SV40 early promoter or by mouse MT promoter were introduced into the cultured mouse fabroblasts, respectively. It was found that both of them could be expressed in the cultured cells. Then, the two recombinant genes were microinjected into the male pronuclei of fertillized mouse eggs for generating transgenic mice harbouring the introduced genes, respectively. However, we did not observed that the two genes could be expressed in transgenic mice. These results suggest that the in vivo expression of human coagulation factor IX cDNA be controlled by some cis regulatory element (s).

Animals↗
PubMed1995

Temporal and spatial distributions of yeast nucleoside diphosphate kinase activities and its association with the Cdc8p.

Nucleoside diphosphate kinase (E.C. 2.7.4.6.) is a broad substrate-specific enzyme that catalyzes the phosphorylation of nucleoside diphosphates to the corresponding triphosphates in nucleic acid biosynthesis. In this report, we investigate its spatial and temporal distributions in yeast to understand how the enzyme exerts its gene function(s). Our results show that the enzyme is predominantly cytoplasmic. A substantial amount of enzyme activity (40-50%) may be associated with the cell membrane. Less than 1% of total activity was detected in the nuclear fraction. Approximately 3% was found in the mitochondrial fraction. When yeast cultures were synchronized, we found that Saccharomyces cerevisiae nucleoside diphosphate kinase did not show cell cycle periodicity, as Schizosaccharomyces pombe enzyme did. To explore its link with DNA synthesis, we investigated its relationship with the Cdc8p (dTMP kinase). We demonstrated a physical interaction between these proteins in vitro, as evidenced that the GST:Cdc8p protein affinity column could retain a subpopulation of nucleoside diphosphate kinase activity from yeast crude extract. Furthermore, when GST:Cdc8p protein was expressed in yeast, the protein could bind to the glutathione-agarose, along with nucleoside diphosphate kinase, suggesting that there is an interaction between GST:Cdc8p and nucleoside diphosphate kinase in vivo. Our results provide evidence for at least a two-enzyme complex that may well facilitate nucleotide channeling in the cell.

Cell Cycle↗
PubMed1994

Direct measurement of glutamate release in the brain using a dual enzyme-based electrochemical sensor.

The in vivo measurement of the rapid changes in the extracellular concentrations of L-glutamic acid in the mammalian brain during normal neuronal activity or following excessive release due to episodes of anoxia or ischemia has not been possible to this date. Current techniques for the measurement of the release of endogenous glutamate into the extracellular space of the central nervous system are relatively slow and do not measure the actual concentration of free glutamate in the extracellular space. An enzyme-based electrode with rapid response times (about 1 s) and high degree of sensitivity (less than 2 microM) and selectivity for L-glutamic acid is described in this paper. This electrode has both L-glutamate and ascorbate oxidase immobilized on its surface. The latter enzyme removes almost completely any interferences produced by the high levels of extracellular ascorbate present in brain tissue. The response of the electrode to glutamate and other potentially interfering substances was fully characterized in vitro and its selectivity, sensitivity and rapidity in responding to a rise in extracellular glutamate concentrations was also demonstrated in vivo. Placement of the electrode in the dentate gyrus of the hippocampus led to the detection of both KCl-induced release of L-glutamic acid and the release induced by stimulation of the axons in the perforant pathway. The development of this selective, sensitive and rapidly responding glutamate sensor should make it now possible to measure the dynamic events associated with glutamate neurotransmission in the central nervous system.

Animals↗
PubMed1994

Isolation of cDNAs encoding guanine nucleotide-binding protein beta-subunit homologues from maize (ZGB1) and Arabidopsis (AGB1).

We have isolated cDNAs from maize (ZGB1) and Arabidopsis (AGB1) encoding proteins homologous to beta subunits of guanine nucleotide-binding protein (G protein). The predicted ZGB1 and AGB1 gene products are 76% identical to each other and 41% or more identical to animal G protein beta subunits. Both predicted proteins contain seven repeats of the so-called "WD-40" motif, where WD is Trp-Asp. RNA blot analysis indicates that ZGB1 mRNA is present in the root, leaf, and tassel and that AGB1 mRNA is expressed in the root, leaf, and flower. DNA blot hybridizations indicate that maize and Arabidopsis genomes contain no other genes that are highly similar to ZGB1 and AGB1, respectively, suggesting that the newly isolated G protein beta-subunit homologues are likely to have unique functions. Furthermore, these G protein beta-subunit homologues are conserved among other plant species and may play important role(s) in plant signaling.

Amino Acid Sequence↗
PubMed1994

Secosteroid mechanism-based inactivators and site-directed mutagenesis as probes for steroid hormone recognition by 3 alpha-hydroxysteroid dehydrogenase.

Rat liver 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSD, EC 1.1.1.50) inactivates circulating androgens, progestins, and glucocorticoids. 3 alpha-HSD is a member of the aldo-keto reductase superfamily, and the X-ray structure of the apoenzyme shows the presence of an (alpha/beta)8 barrel [Hoog, S. S., Pawlowski, J. E., Alzari, P. M., Penning, T. M., & Lewis, M. (1994) Proc. Natl. Acad. Sci. U.S.A. 91, 2517-2521]. As yet, a three-dimensional structure of the ternary complex E.NADPH.steroid is unavailable. To identify regions of the enzyme involved in steroid hormone recognition, we have employed mechanism-based inactivators and site-directed mutagenesis. (3 RS)-1,10-Seco-5 alpha-estr-1-yne-3,17 beta-diol (1) and (17 RS)- 17-hydroxy-14,15-secoandrost-4-en-15-yn-3-one (3) are secosteroids which contain latent Michael acceptors (alpha,beta-unsaturated alcohols) at opposite ends of the steroid nucleus (at the C-3 and C-17 positions, respectively). It was found that compounds 1 and 3 inactivated 3 alpha-HSD only in the presence of NAD+. The requirement for cofactor implies that 1 and 3 are oxidized to the corresponding alpha,beta-unsaturated ketones for inactivation to occur. Chemically prepared 17 beta-hydroxy-1,10-seco-5 alpha-estr-1-yn-3-one (2) and 14,15-secoandrost-4-en-15-yne-3,17-dione (4), the presumed products of 1 and 3 oxidation, behaved as stoichiometric inactivators of 3 alpha-HSD. In the presence and absence of NAD+, 2 and 4 inactivated > 50% of the enzyme in 10 s or less.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Hydroxysteroid Dehydrogenases↗
PubMed1994

Appearance of a novel Ca2+ influx pathway in Sf9 insect cells following expression of the transient receptor potential-like (trpl) protein of Drosophila.

Activation of phospholipase C, elevation of free cytosolic Ca2+ concentration ([Ca2+]i) and stimulation of Ca2+ influx have been implicated in Drosophila phototransduction. Electrophysiological studies suggest that trp and trpl proteins may be important for the light-activated Ca2+ current found in Drosophila photoreceptor cells. Although these proteins exhibit homologies to voltage-gated Ca2+ and Na+ channels, their actual function in insect cells and their relation to proteins involved in mammalian cell Ca2+ signaling remains unknown. In the present study, [Ca2+]i was examined in fura-2-loaded Sf9 insect cells infected with recombinant baculovirus containing cDNA for the trpl protein. Ca2+ influx was examined by use of Ba2+, a Ca2+ surrogate that is not a substrate for Ca(2+)-pumps or carriers and by measurement of whole-cell membrane currents. The results suggest that expression of trpl is associated with appearance of a Ca2+ permeable, non-selective cation channel formed by the trpl protein.

Animals↗
PubMed1994

Synaptobrevin/vesicle-associated membrane protein (VAMP) of Aplysia californica: structure and proteolysis by tetanus toxin and botulinal neurotoxins type D and F.

Synaptobrevin/vesicle-associated membrane protein (VAMP) and syntaxin are potential vesicle donor and target membrane receptors of a docking complex that requires N-ethylmaleimide-sensitive factor (NSF) and soluble NSF-attachment proteins as soluble factors for vesicle fusion with target membranes. Members of this docking complex are the target of clostridial neurotoxins that act as zinc-dependent proteases. Molecular cloning of the Aplysia californica synaptobrevin cDNA revealed a 180-residue polypeptide (M(r), 19,745) with a central transmembrane region and an atypically large C-terminal intravesicular domain. This polypeptide integrates into membranes at both the co- and posttranslational level, as shown by modification of an artificially introduced N-glycosylation site. The soluble and membrane-anchored forms of synaptobrevin are cleaved by the light chains of the botulinal toxins type D and F and by tetanus toxin involving the peptide bonds Lys49-Ile50, Gln48-Lys49, and Gln66-Phe67, respectively. The active center of teh tetanus toxin light chain was identified by site-specific mutagenesis. His233, His237, Glu234, and Glu270/271 are essential to this proteolytic activity. Modification of histidine residues resulted in loss of zinc binding, whereas a replacement of Glu234 only slightly reduced the zinc content.

Amino Acid Sequence↗