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Biomedical subjects

Q Xu

Publications and source records attributed to Q Xu.

At least 379 records · Page 21Linked to original sources
PubMed1995

[Expression of intercellular adhesion molecule-1 and vascular adhesion molecule-1 in kidney of patients with lupus nephritis and membranoproliferative glomerulonephritis].

Immunohistochemical and computer-imaging analysis techniques were used to detect the expression of intercellular adhesion molecule 1 (ICAM-1) and vascular adhesion molecule 1 (VCAM-1) in the kidney of 25 patients with lupus nephritis (LN) type IV and in 15 patients with membranoproliferative glomerulonephritis (MPGN) type I. Results showed that ICAM-1 and VCAM-1 expressions were increased significantly in the kidneys of patients with MPGN and LN and that ICAM-1 in the glomeruli of LN patients correlated well with glomerular endothelial cell proliferation. ICAM-1 and VCAM-1 may well take a role in the pathogenesis of LN and MPGN.

Cell Adhesion Molecules↗
PubMed1995

Evaluation of serum troponin T measurement in acute myocardial infarction.

The release kinetics of the cardiac specific troponin T (cTnT), measured by an immunosorbent assay, in 32 patients with acute myocardial infarction (AMI) was evaluated. In 8 AMI patients (25%), the release kinetics of serum cTnT showed biphasic serum concentration curves with a large peak at 10 to 18 hours after onset and the serum cTnT concentrations were up to 30 to 120 times of the normal upper limit-detected (0.2 microgram/ml), and another samll cTnT peak at 70 to 100 hours after onset of pain. The serum cTnT measurements in the remaining 24 AMI patients (75%) gave only one large peak which was around 32 to 108 hours after onset of pain. cTnT appeared in serum as early as 3 to 4 hours and remained elevated until 240 hours after the infarctions. The results indicated that (1) cTnT was a sensitive and specific marker of AMI; (2) the biphasic curve of cTnT releae in general, the ratio of cTnT at around 14 to 32 (14/32) > 1 in particular, may be a useful marker suggesting early reperfusion; (3) the continuous elevation of serum cTnT in AMI course might be a prognostic indicator for unfavorable outcomes.

Aged↗
PubMed1995

[Manometric study of the esophagus and intrathoracic stomach after partial esophagectomy for carcinoma].

The pressure in the residual esophagus and in the thoracic stomach was measured by using SG-II computer manometer in 25 patients who underwent resection of esophageal cancer. Thirty normal mean were chosed as controls. The results indicated that a high pressure zone was present above the esophago-gastric anastomosis. It may be helpful in preventing and reducing reflux esophagitis. We stress that the prevention of gastroesophageal reflux after the operation is related to the operative method and the topography of the stomach.

Adult↗
PubMed1995

Atherosclerosis as an autoimmune condition.

Atherosclerosis is a multifactorial vascular disorder responsible for the highest rate of mortality in the western world. During the last decades, research on this disease has primarily focused on the role of lipids, which are essential to the formation of lesions in the vascular intima that ultimately leads to clinically apparent atherosclerotic plaques. More recently, several anecdotal findings have indicated the possible involvement of the immune system in the process of atherogenesis. In particular, the appearance of immunocompetent cells as well as humoral antibodies in the intima in the early stages of disease development supports the view of an inflammatory component in this disorder. In addition to the search for lipid-associated antigens that might entail full-blown atherosclerosis, other candidate antigens capable of inducing an immune response in the vascular wall have also been explored. Within the probable group of antigens for immune responsiveness, heat shock protein (hsp) 60/65 became a serious candidate, upon observation that immunization of rabbits with this protein led to arteriosclerotic changes of the aortic intima. In the last few years we have established this rabbit model for immunologic investigations of atherosclerosis and, in parallel, examined the pathogenesis of human atherosclerosis with regard to hsp 60/65 immune reactivity. Currently available data point to an autoimmune induction of early inflammatory arteriosclerotic changes triggered by a cellular and humoral immune reaction to stress-induced hsp 60-expressing areas of the endothelial cells.

Animals↗
PubMed1995

Magnetic resonance imaging and microsurgical treatment of intramedullary hemangioblastoma of the spinal cord.

Thirteen cases of intramedullary hemangioblastoma of the spinal cord were studied radiologically, especially with magnetic resonance imaging (MRI). Microsurgery was used to remove the tumors in all cases. Signs and symptoms were improved in 84.6% of the cases after operation. The diagnosis and microsurgical techniques for excision of intramedullary hemangioblastoma of the spinal cord are discussed. This disease should be differentiated from hydromyelia, intramedullary ependymoma, and vascular malformation of the spinal cord. Total removal of the tumor is recommended.

Adolescent↗
PubMed1995

[Hoffa disease: diagnosis and arthroscopic treatment].

The diagnosis of Hoffa disease (syndrome of impigement of the infrapatellar fat pad) was established in 20 patients with anterior knee pain by clinical physical examination, magnetic resonance imaging and arthroscopic findings. Arthroscopic partial or total resections of the infrapatellar fat pad were performed after arthroscopic examination. According to the Larson's rating score for knee function, 18 cases had a satisfactory result at an average follow-up of 36 months. The results of follow-up also suggested there was no significant difference between the partial and total resections of the fat pad.

Adipose Tissue↗
PubMed1995

[Arthroscopic evaluation and treatment of the disorder resulted from open meniscectomy of the knee].

Between 1989 and 1994, twenty four cases of knee disorders caused by open meniscectomy had undergone the second operation by arthroscopic procedures. The results of retrospective study indicated that main reasons of early disorders following meniscectomy were locking of remanent posterior horn, tears of remanent meniscus and injuries of fat pad and the cause of late disorders were single compartment osteoarthritis and genu varum/valgum caused by meniscectomy. In early cases, the arthroscopic reshape or removal of meniscal remanents and partial resection of fat pads could get satisfactory results. In late cases of osteoarthritis with genu varum/valgum, arthroscopic debridement, high osteotomy of tibia or knee replacement should be carried out as means of treatment.

Adult↗
PubMed1995

[Risk factors on hyperglycemia in newborn infants].

OBJECTIVE: To investigate high risk factors of neonatal hyperglycemia. METHODS: According to the gestational age, postnatal age, weight, hypoxia, infection, 336 hospitalized newborns receiving continuous intravenous infusion of glucose controlled by pump were divided into the study and control groups respectively, the incidences of hyperglycemia between two groups were analysed statistically. RESULTS: The results showed that the high risk factors of neonatal hyperglycemia were gestational age ( < 37 week), postnatal age ( < 72h), weight ( < 2 500g), hypoxia and (or) infection. CONCLUSIONS: In neonates with one or more high risk factors of hyperglycemia, strict control of infusion speed; treatment of original diseases and frequent monitoring of blood glucose should be noted.

Glucose↗
PubMed1995

[Histochemical observation of the effect of electroacupuncture on the livers of rats with endotoxic shock].

The experimental rats were randomly divided into three groups: i.e. control group; endotoxic shock group (the model of endotoxic shock was induced by intravenous administration of E. Coli endotoxin, 16 mg/kg); and electroacupuncture (EA) group ("Renzhong" or "Zusanli" acupoint was stimulated for 15 minutes at 1 hr after injection of endotoxin). The experimental rats were decapitated at 75 minutes after injecting endotoxin. Their livers were taken out for cryostat section, and histochemical observation. The results were as follows: 1) The glycogen in the hepatic cells of endotoxic shocked rats were almost completely depleted. The activities of SDH Mg(++)-ATPase and G-6-Pase and 5'-Nase were decreased; especially the activities of 5'-Nase in the biliary canaliculi and sinusoids were apparently reduced. 2) The content of hepatic glycogen in EA group was increased, but some of them was still depleted. The activities of SDH, Mg(++)-ATPase and G-6-Pase were slightly increased as compared with that of the endotoxic shock group. The activity of 5'-Nase was obviously increased after EA. The preliminary results indicated that EA at "Renzhong" or "Zusanli" acupoint of rats with endotoxic shock might play certain role on improving the hepatic metabolism and promoting the membrane transport action.

Animals↗
PubMed1994

Secondary structure of the 33 kDa, extrinsic protein of Photosystem II: a far-UV circular dichroism study.

The 33 kDa extrinsic protein of Photosystem II is an important component of the oxygen-evolving apparatus which functions to stabilize the manganese cluster at physiological chloride concentrations and to lower the calcium requirement for oxygen evolution. Chou-Fasman analysis of the amino-acid sequence of this protein suggests that this component contains a high proportion of alpha-helical structure and only relatively small amounts of beta-sheet structure. A computational study using more sophisticated techniques (Beauregard, M. (1992) Environ. Exp. Bot. 32, 411-429) concluded that the protein contained little periodically ordered secondary structure. In this study, we have directly measured the relative proportions of secondary structure present in the 33 kDa protein using far-ultraviolet circular dichroism spectroscopy. Our results indicate that, in solution, this protein contains a large proportion of beta-sheet structure (38%) and relatively small amounts of alpha-helical structure (9%). A structural model of the 33 kDa protein based on a constrained Chou-Fasman analysis (Teeter, M.M. and Whitlow, M (1988) Proteins 4, 262-273) is presented.

Amino Acid Sequence↗
PubMed1994

Compatibility of paclitaxel injection vehicle with intravenous administration and extension sets.

The compatibility of paclitaxel injection vehicle with a variety of i.v. administration and extension sets was studied in terms of the amount of diethylhexyl phthalate (DEHP) leached from the sets. Test solutions of paclitaxel injection vehicle corresponding to paclitaxel injection 0.3 and 1.2 mg/mL were prepared in polyolefin bags of 5% dextrose injection. The solutions were delivered in triplicate over 24 hours through 26 models of administration sets and 24 models of extension sets and collected in glass containers. Portions were removed after delivery and analyzed in duplicate for DEHP concentration by high-performance liquid chromatography. All the extension sets were compatible with paclitaxel injection vehicle. Most of the administration sets were also compatible. However, two administration sets were incompatible with paclitaxel vehicle corresponding to either drug concentration, and five sets were incompatible with the vehicle simulating the high (1.2-mg/mL) concentration. Some of the incompatible sets were labeled as not containing polyvinyl chloride (PVC). Solutions of paclitaxel vehicle leached DEHP from administration sets containing PVC and from some sets labeled as not containing PVC.

Chromatography, High Pressure Liquid↗
PubMed1994

Compatibility and stability of ondansetron hydrochloride with morphine sulfate and with hydromorphone hydrochloride in 0.9% sodium chloride injection at 4, 22, and 32 degrees C.

The physical compatibility and chemical stability of ondansetron hydrochloride 0.1 and 1 mg/mL with morphine sulfate 1 mg/mL and with hydromorphone hydrochloride 0.5 mg/mL in 0.9% sodium chloride injection were studied. Test solutions of the drugs in 0.9% sodium chloride injection were prepared in triplicate and stored at 4, 22, and 32 degrees C. Samples were removed immediately and at various time points over 31 days and stored at -70 degrees C until analyzed. Physical compatibility was assessed visually and by measuring turbidity with a color-correcting turbidimeter and particle content with a light-obscuration particle sizer and counter. Chemical stability was determined by measuring the concentration of each drug in duplicate with stability-indicating high-performance liquid chromatography. There were no visual or subvisual changes in turbidity or particle content in any of the test solutions at any of the time points. There was little or no loss of any of the drugs. When admixed in 0.9% sodium chloride injection, ondansetron hydrochloride 0.1 and 1 mg/mL plus morphine sulfate 1 mg/mL or hydromorphone hydrochloride 0.5 mg/mL were compatible and stable for at least 7 days at 32 degrees C and for at least 31 days at 4 and 22 degrees C.

Chromatography, High Pressure Liquid↗
PubMed1994

Mutational analysis of photosystem I polypeptides in Synechocystis sp. PCC 6803. Subunit requirements for reduction of NADP+ mediated by ferredoxin and flavodoxin.

The subunit requirements for NADP+ reduction by photosystem I were assessed in mutants of Synechocystis sp. PCC 6803 created by targeted inactivation of the psaD, psaE, psaF, and psaL genes. The PsaE-less, PsaF-PsaJ-less, and PsaL-less mutants showed normal photoautotrophic growth, while the growth of PsaD-less mutants was slower without glucose. In isolated wild-type membranes, the rate of flavodoxin reduction and flavodoxin-mediated NADP+ reduction were 800 and 480 mumol/mg of chlorophyll/h, respectively. The rate of ferredoxin-mediated NADP+ photoreduction was 460 mumol/mg of chlorophyll/h. There was no diminution in NADP+ photoreduction in membranes isolated from the PsaF-less and PsaL-less mutants. The rates of ferredoxin-mediated NADP+ photoreduction in membranes of the PsaE-less mutants were 25 mumol/mg of chlorophyll/h. However, the rate of flavodoxin reduction was 380 mumol/mg of chlorophyll/h, and that of flavodoxin-mediated NADP+ photoreduction was 170 mumol/mg of chlorophyll/h. PsaD-less membranes showed < 20% of the wild-type rates of flavodoxin-mediated NADP+ photoreduction, but were completely deficient in ferredoxin-mediated NADP+ photoreduction. Therefore, the roles of PsaE and PsaD are more crucial for "docking" of ferredoxin than of flavodoxin. Proteolysis studies showed that while PsaD was susceptible to rapid in vitro degradation by thermolysin, the number and sizes of protease-resistant fragments were not affected by the absence of PsaE. Protease accessibility studies further indicated that the C-terminal domain of PsaD is surface-exposed on the n-side. These results suggest that PsaE and the C-terminal domain of PsaD generate the docking site for the electron acceptors of photosystem I.

Bacterial Proteins↗
PubMed1994

Course of spinocerebellar axons in the ventral and lateral funiculi of the spinal cord with projections to the anterior lobe: an experimental anatomical study in the cat with retrograde tracing techniques.

The fiber course of the spinocerebellar tracts in the ventral and lateral funiculi of the cat spinal cord were studied by a new approach, making cordotomies at different spinal levels or lesions of the restiform body followed by injections of HRP or WGA-HRP into the anterior cerebellar lobe. The retrogradely labeled axons showed characteristic distribution patterns related to the level and extent of the lesions. The results show the following. 1) The dorsal spinocerebellar tract (DSCT) originating ipsilaterally from the thoracic and upper lumbar segments ascends in the dorsolateral fasciculus. It undergoes a dorsal shift during its rostral course. The tract is topically arranged and passes through the restiform body. 2) The ventral spinocerebellar tract (VSCT) arising contralaterally from lower thoracic, lumbar, and more caudal segments passes via the ventral funiculus and ascends in the ventrolateral fasciculus. This tract is also topically arranged. It makes a lateral and then a dorsal shift during its ascending course. The main portion of the VSCT enters the cerebellum via the superior cerebellar peduncle. A minor portion originating from the sacrococcygeal region enters via the restiform body. 3) The spinocerebellar fibers originating ipsilaterally from the cervical enlargement ascend in the lateralmost part of the lateral funiculus in the area between the dorsolateral and ventrolateral fasciculi. These fibers form two groups, one passing through the restiform body, the other through the superior cerebellar peduncle. 4) The spinocerebellar fibers originating contralaterally from the central cervical nucleus pass through the ventral funiculus and ascend in the lateralmost part of the lateral funiculus, mainly in the ventrolateral fasciculus. Most of the fibers seem to pass through the superior cerebellar peduncle.

Animals↗
PubMed1994

Function and organization of photosystem I in a cyanobacterial mutant strain that lacks PsaF and PsaJ subunits.

Photosystem I functions as a light-driven plastocyanin-ferredoxin oxidoreductase in the photosynthetic membranes of cyanobacteria and chloroplasts. A mutant strain of the cyanobacterium Synechocystis sp. PCC 6803 that contains a deletion of the psaF gene and a transcriptionally inactive psaJ gene has assembled photosystem I complexes that lack PsaF, a lumenal protein and PsaJ, a 4-kDa hydrophobic protein. The cells of the mutant and wild type strains have similar rates of photosynthetic electron transfer and P700+ rereduction under linear and cyclic electron transfer conditions. Analysis of flash-induced absorption transients at 700 nm demonstrate that the absence of PsaF in purified mutant photosystem I did not affect the rate of P700 rereduction by cytochrome c553. Therefore, PsaF is not essential for docking of cytochrome c553. We also studied the organization of the proteins of mutant and wild type photosystem I by comparing their accessibility to digestion by thermolysin or to removal by 1 M NaI. The PsaA-PsaB subunits were more easily degraded by thermolysin in the mutant photosystem I. Thermolysin cleavage of PsaB yielded two major fragments that were immunoreactive with an antibody raised against the C terminus of PsaB. The N termini of these PsaB peptides mapped at Ile482 and Ile498 residues, thus identifying a surface-exposed domain of the core of photosystem I. The PsaE subunit could be removed by 1 M NaI and was rapidly digested by thermolysin in the mutant but not in the wild type photosystem I. Therefore, PsaF and PsaJ subunits of photosystem I have dispensable accessory roles in the function and organization of the complex.

Amino Acid Sequence↗
PubMed1994

Cloning and identification of testis-specific transcription elongation factor S-II.

A new S-II cDNA clone was isolated from a rat testis library. This cDNA contained an open reading frame encoding 299 amino acid residues. The deduced amino- and carboxyl-terminal regions were very similar with those of Ehrlich cell S-II, which we reported previously, but the sequence of the intervening 46 amino acid residues was unique. This new S-II was expressed in the testis but not in the other rat tissues examined, suggesting that it was a testis-specific S-II. Recombinant testis-specific S-II produced in Escherichia coli was shown to stimulate RNA polymerase II.

Amino Acid Sequence↗