Biomedical subjects

S Xu

Publications and source records attributed to S Xu.

At least 307 records · Page 17Linked to original sources

PubMed1998

[The protective effect of captopril during myocardial ischemia and reperfusion and its mechanism].

OBJECTIVE: To investigate the myocardial protective effect of captopril (Cpl) during ischemia and reperfusion injury. METHODS: Sixteen mongrel dogs were randomly divided into the control and Cpl groups. In the control group, only modified St. Thomas cardioplegia was used. In the Cpl group, St. Thomas cardioplegia and reperfusional blood containing captopril 4.6 mumol/L were used. The plasma renin activity (RA), contents of angiotensin II (AT-II) and endothelin-1 (ET-1) in arterial blood were determined before cardiopulmonary bypass (CPB) and 5, 35, 60 min after reperfusion. The myocardial RA, contents of AT-II, ET-1 and malondyldialdehyde (MDA) were also measured. Parameters of cardiac function were monitored simultaneously. RESULTS: In the control group the plasma RA, AT-II and ET-1 contents were increased after reperfusion and significantly higher than those before CPB (P < 0.01). However, the content of AT-II in the Cpl group was not increased after reperfusion. The content of ET-1 in the Cpl group was increased but significantly lower than that in the control group (P < 0.01). The myocardial AT-II, ET-1 and MDA contents in the Cpl group were significantly lower than those in the control group. The cardiac index (CI) and coronary blood flow (CBF) in the Cpl group regained normal after reperfusion at 35 min. CONCLUSIONS: Cardioplegia and reperfusion blood containing 4.6 mumol/L captopril could ameliorate the cardiac performances by inhibiting myocardial and systemic RAS and decreasing the ET-1 production.

Angiotensin II↗

PubMed1998

[Clinical features, diagnosis and treatment of solitary vertebral arch tuberculosis].

OBJECTIVE: To explore clinical features of vertebral arch tuberculosis, and to discuss the diagnosis and treatment of this illness. METHOD: Seventeen of 3,825 cases of spinal tuberculosis who were hospitalized and treated from 1956 to 1996 were reviewed, and their clinical features, diagnosis and treatment were analyzed and reported. RESULT: Sixteen cases of vertebral arch tuberculosis were in adolescence and prime of life, and another one was a 2-year-old child. Their symptoms in early stages were untypical, including local fixed pain and tenderness, and later, abscess, fistula and symptoms of nerve system appeared. All the cases were diagnosed through summarizing of their history, signs, imaging examination and bacteriology tests, and only one case was misdiagnosed. In one of 17 cases, antituberculosis chemotherapy was conducted alone and non-operation was performed. In the other 16 cases, focal debridement of vertebral arch was performed on the basis of antituberculous chemotherapy, and in 4 cases of them with symptoms of nerve system, laminectomy and spinal decompression was performed homochronously. All the cases were healed and no relapse occurred during follow-up. CONCLUSION: It is difficult to diagnose vertebral arch tuberculosis in early stages due to its occult symptoms, but the symptom of confined pain and manifestation in X-ray, CT and MRI are much useful for early diagnosis. Abscess puncture and acid-fast staining smear microscopy can usually be used to confirm diagnosis. And surgical intervention is an important measure for its treatment.

Adolescent↗

PubMed1998

[Effect of Fucong tablets and its ingredients on ototoxicity of gentamycin in guinea pigs].

OBJECTIVE: To assess the antagonistic effect of Fucong Tablet (FCT) and its ingredients on ototoxicity of gentamycin in guinea pigs. METHODS: The guinea pigs were given gentamycin 80 mg/kg intramuscularly once daily for 20 days and FCT or its ingredients separately oral taken for 20 days. The auditory brain stem evoked response (ABR) threshold, vascular stria blood circulation condition, outer hair-cell count and cochlear ultrastructure of guinea pigs were observed before and after treatment to assess the antagonistic effect and protective effect of FCT on cochlear structure. RESULTS: FCT and its ingredients of tonifying Kidney, replenishing Qi and blood, promoting blood circulation could lower the impairment ratio of outer hair-cell induced by gentamycin (P < 0.05), protect morphosis and function of cochlea and lower the elevated ABR threshold (P < 0.05). CONCLUSIONS: FCT and its ingredients could reduce the toxic damage on ear induced by gentamycin effectively.

Animals↗

PubMed1998

[Study on gas exchange of the patients with lung cancer in perioperation].

OBJECTIVE: To study changes of gas exchange in perioperative patients with lung cancer. METHOD: Indices including P/F, a/A, P50O2 and PaCO2 on gas exchange in 68 male patients(50-78 y) with lung cancer were monitored on preoperative day 1 2 3 and postoperative day 7. RESULT: Comparing with preoperation data P/F a/A decreased significantly in 3 days(P < 0.01) and PaCO2 P50O2 increased significantly on the day after operation (P < 0.01), especially in the group of pneumonectomy and abnormal ventilation, hypoxemia measured in preoperation. CONCLUSION: The gas exchange of the patients with lung cancer reduced significantly in postoperative 3 days.

Aged↗

PubMed1998

[Assessment of responsiveness of spontaneous baroreceptor-heart rate reflex under gravitational stress].

Beat by beat arterial blood pressure was measured using Finapres 2300 monitor. Sequences of 3 or more beats with systolic pressure and next beat interval changed in the same direction were identified as baroreflex sequences from 6-min data segments. A linear regression was applied to each sequence and the slope (correlation coefficient > or = 0.85) was taken as a measure of the baroreflex response slope (BRS). The changes in mean BRS during + 65 degrees head-up tilt (HUT), -6.67 kPa lower body negative pressure (LBNP) and 16 days -6 degrees head-down tilt (HDT) bed rest were observed. The results showed that there was a significant decrease in the mean BRS during LBNP or HUT as compared with that of the supine control, though the blood pressure responses differed. The mean BRS was also significantly decreased during bed rest. It suggests that the responsiveness of spontaneous baroreceptor-heart rate reflex can be evaluated in humans under gravitational stress.

Adaptation, Physiological↗

PubMed1998

[Mechanism of Canscora lucidissima xanthones against arrhythmia induced by myocardial ischemia-reperfusion in rats].

OBJECTIVE: To study the protective effect of 1,8-dihydroxy-3,5- dimethoxyxanthone (Xan-I) 1-hydroxy-5-dimethoxyxanthone(Xam-II) and 1-hydroxy-3,7,8-trimethoxyanthone (Xan-III) on arrhythmia induced by myocardial ischemia-reperfusion injury and their mechanism. METHOD: A rat model was used. The experimental result shows that. RESULT: An intravenous injection of Xan-I, Xan-II and Xan-III 1 mg/kg given 3 min before left coronary artery ligation reduces significantly the incidence of ventricular arrhythmia and its duration, diminishes the release of glutamic oxaloacetic transaminase and lactate dehydrogenase, elevates the activity of superoxide dismutase and reduces the amount of malondialdehyde. The potency of the above effect among 3 Xans is Xan-I > Xan-III > Xan-II. CONCLUSION: It follows that the protective effect of Xans on myocardial ischemia reperfusion induced by arrhythmia might be associated with the reduction of myocardial lipid peroxidation and the enhancement of SOD activity, and the amount and site of-OH(hydroxy) and -OCH3 (methoxy) on the benzenoid structure may be related to the affinity of Xan.

Animals↗

PubMed1998

[An experimental observation of repair after transection of cauda equina fibers in cat].

OBJECTIVE: To explore the regeneration characteristics after cauda equina transection. METHODS: Fibrin glue was chosen to repair transected left L6,7 roots in cat, and right roots in situ of the transected ends were served as the control. The characteristics of regeneration were observed by immunohistocytochemistry and morphometric analysis. RESULTS: Regeneration was found not only in site of anastomosis, but also in corresponding spinal segments and DRGs. Sensory and motor evoked potentials (SEP and MEP) performed before and after transection and before taking specimen revealed the course of functional recovery on severed and regenerated nerve roots. The regeneration of moter roots was better than that of sensory roots, and they were mainly blocked at the site of central-peripheral transition zone. CONCLUSIONS: The method of adhesion by fibrin glue can replace traditional suture, and it is superior to suture.

Animals↗

PubMed1998

Clinical observation on vertical transmission of human papillomavirus.

OBJECTIVE: To observe the possibility of maternal-fetal vertical transmission of human papillomavirus (HPV) via amniotic fluid. SUBJECTS AND METHODS: Specimens of cervical secretions from 30 pregnant women were obtained during the third trimester before rupture of membrane, and specimens of pharyngeal secretions of their neonates were obtained 12-48 h after birth. Amniotic fluids were collected in 13 pregnant women during cesarean section. The presence of HPV types 6, 11, 16, 18, 31, 33, 35, 38 deoxyribonucleic acid were detected by consensus polymerase chain reaction. RESULTS: HPV deoxyribonucleic acid was found in 16 cervical secretions, 14 pharyngeal secretions and in 3 amniotic fluids, the positive rate was 53.3%, 46.7%, 23.1% respectively. The pharyngeal secretion was also HPV positive in one of the three neonates from the amniotic fluid positive mothers. CONCLUSION: The results indicate that HPV can be transmitted in utero through amniotic fluid and cesarean section can not protect the neonates against vertical transmission completely.

Adult↗

PubMed1998

[Surgical treatment of infective endocarditis].

OBJECTIVE: To summarize the experience of surgical treatment of infective endocarditis in 28 patients. METHOD: Open heart surgery under cardiopulmonary bypass was performed in all patients: valve replacement (24), VSD repair and tricuspid annuloplasty (3), and Bentall (1) 17 mechanical and 7 homograft valves were placed. RESULT: Two died in hospital, 4 died from infection, 1 had periprosthetic leakage and incompetence respectively. 22 survivors showed improved heart function. CONCLUSION: Combined medication and surgical treatment is superior to antibiotic treatment in long-term survival and convalescence. Infective reccurrence, reinfection and advanced heart failure are major risk factors after operation.

Adolescent↗

PubMed1998

[Timosaponins E1 and E2].

By means of silica gel chromatography and HPLC, two compounds were isolated from Anemarrhena asphodeloides Bge.. On the basis of chemical and spectral (MS, 1H, 13CNMR, IR) analyses, their structures were elucidated as (25S)-26-O-beta-D-glucopyranosyl-22-hydroxy-5 beta-furost-3 beta, 15 alpha, 26-triol-3-O-beta-D-glucopyranosyl (1-->2)-beta-D-galactopyranoside (1), and (25S)-26-O-beta-D-glucopyranosyl-22-methoxy-5 beta-furost-3 beta, 15 alpha, 26-triol-3-O-beta-D-glucopyranosyl (1-->2)-beta-D-galactopyranoside (2). They are named as timosaponin E1 (1) and timosaponin E2 (2) respectively. The structure of anemarrhenasaponin-I (A) is briefly discussed. Timosaponins are the main active constituents of Anemarrhena asphodeloides, most of them were shown to can inhibit platelet aggregation.

Anemarrhena↗

PubMed1998

[Effect of eel oil capsule on mice memory].

Step-down test, step-through test and water maze in mice were used to observe the effect of eel oil capsule on mice memory. The results indicated that during the administration period (30 days), the eel oil capsule treating groups with dosages of 0.129, 0.387, and 1.161 g/kg obviously improved the learning and memory abilities. Compared with the control test, the eel oil capsule promoted the memory and smart.

Animals↗

PubMed1998

[Clinical manifestation of AIDS in oral and maxillofacial region (Report of a case)]

The prevalence morbidity of AIDS rises day after day. As the first symptom of this disease usually occurs in maxillofacial region,it must be well attentioned to the dentists. Here introducing a case who was a patient of AIDS. He was first see doctor in july 1995 in our Department, associating with foreign documents, the authors described all kinds of clinic symptoms of AIDS on oral and maxillofacial region in early to late stage.The typical one includes hairy leukoplakia,monilia albicans infection of angular stomatitis and mucous membrane,KS,etc.At last,the authors indicated there are some preventive methods to the disease for the dentists.

Journal Article↗

PubMed1998

In vivo three-dimensional MR microscopy of mice with chronic relapsing experimental autoimmune encephalomyelitis after treatment with insulin-like growth factor-I.

PURPOSE: The purpose of this study was to determine the ability of three-dimensional in vivo MR microscopy to depict the treatment effects of insulin-like growth factor-I (IGF-I) in SJL mice with chronic relapsing experimental autoimmune encephalomyelitis (crEAE). METHODS: The experiments were performed at 4.7-T on 10 crEAE mice and on one set of control animals. Five crEAE mice were treated with IGF-I and five were treated with a placebo. RESULTS: In the crEAE mice treated with the placebo, in vivo MR microscopy showed areas of abnormal signal throughout the cerebrum, brain stem, and cerebellum. These findings were not present in either the IGF-I-treated mice or the normal control animals. The diffuse alterations in signal intensity in the placebo-treated crEAE mice were not identified on histologic sections of the same areas. CONCLUSION: Differences between the IGF-I- and placebo-treated groups may reflect changes in stabilization or permeability of cell membranes and/or of the blood-brain barrier, although other alternative contrast mechanisms could be playing a role. In vivo MR microscopy depicted changes resulting from treatment of crEAE with IGF-I.

Animals↗

PubMed1997

MEKK1 binds directly to the c-Jun N-terminal kinases/stress-activated protein kinases.

Mitogen-activated protein (MAP) kinases mediate responses to a wide array of cellular stimuli. These cascades consist of a MAP kinase or extracellular signal-regulated kinase (ERK), activated by a MAP/ERK kinase (MEK), in turn activated by a MEK kinase (MEKK). MEKK1 has been shown to be a strong activator of the c-Jun N-terminal kinase/stress-actived protein kinase (JNK/SAPK) pathway. We report here that JNK/SAPK binds directly to the N-terminal, noncatalytic domain of MEKK1 in vitro and in transfected cells. Immobilized MEKK1-derived peptides extract JNK/SAPK selectively from cell lysates. MEKK1 coimmunoprecipitates with multiple JNK/SAPK isoforms in transfected cells. Expression of the N terminus of MEKK1 lacking the kinase domain increases activation of endogenous JNK/SAPK by MEKK1. The data are consistent with a model in which MEKK1-JNK/SAPK binding facilitates the receipt of signals from upstream inputs and localizes JNK/SAPK to intracellular targets of the pathway.

Amino Acid Sequence↗

PubMed1997

A cluster of four novel human G protein-coupled receptor genes occurring in close proximity to CD22 gene on chromosome 19q13.1.

In our search for novel human galanin receptor (GALR) subtypes, human genomic DNA was PCR amplified using sets of degenerate primers based on conserved sequences in human and rat GALR. The sequence of one of the subcloned PCR products revealed homology to a sequence in the 3' region of the human CD22 gene following a BLAST search of GenBank's database. A search for open reading frames (ORF) in the non-coding CD22 sequence resulted in identification of two novel putative intronless genes, GPR40 and GPR41. The recent submission of sequence overlapping the downstream CD22 sequence revealed a possible polymorphic insert containing a third intronless gene, GPR42, sharing 98% amino acid identity with GPR41, followed by a fourth intronless gene, GPR43. Thus, the GPR40, GPR41, GPR42, and GPR43 genes, respectively, occur downstream from CD22, a gene previously localized on chromosome 19q13.1. The four putative novel human genes encode new members of the GPCR family and share little homology with GALR.

Amino Acid Sequence↗

PubMed1997

Cloning of the BssHII restriction-modification system in Escherichia coli : BssHII methyltransferase contains circularly permuted cytosine-5 methyltransferase motifs.

BssHII restriction endonuclease cleaves 5'-GCGCGC-3' on double-stranded DNA between the first and second bases to generate a four base 5'overhang. BssHII restriction endonuclease was purified from the native Bacillus stearothermophilus H3 cells and its N-terminal amino acid sequence was determined. Degenerate PCR primers were used to amplify the first 20 codons of the BssHII restriction endonuclease gene. The BssHII restriction endonuclease gene (bssHIIR) and the cognate BssHII methyltransferase gene (bssHIIM) were cloned in Escherichia coli by amplification of Bacillus stearothermophilus genomic DNA using PCR and inverse PCR. BssHII methyltransferase (M.BssHII) contains all 10 conserved cytosine-5 methyltransferase motifs, but motifs IX and X precede motifs I-VIII. Thus, the conserved motifs of M. BssHII are circularly permuted relative to the motif organizations of other cytosine-5 methyltransferases. M.BssHII and the non-cognate multi-specific phiBssHII methyltransferase, M.phiBss HII [Schumann,J. et al . (1995) Gene, 157, 103-104] share 34% identity in amino acid sequences from motifs I-VIII, and 40% identity in motifs IX-X. A conserved arginine is located upstream of a TV dipeptide in the N-terminus of M.BssHII that may be responsible for the recognition of the guanine 5' of the target cytosine. The BssHII restriction endonuclease gene was expressed in E.coli via a T7 expression vector.

Amino Acid Sequence↗

PubMed1997

Calcium ionophore-treated peripheral blood monocytes and dendritic cells rapidly display characteristics of activated dendritic cells.

Human peripheral blood contains a small subpopulation of immature dendritic cells (iDC) distinguished from circulating monocytes by their low expression of CD14. We utilized leukapheresis and countercurrent centrifugal elutriation to obtain myeloid origin mononuclear cell (MOMC) fractions of monocytes and iDC for study. These subpopulations were ultrastructurally and immunophenotypically similar before culture. After a 20- to 96-h culture either alone, with recombinant human granulocyte-monocyte CSF, or with endotoxin, greater up-regulation of costimulatory molecule expression was observed among iDC than among monocytes, and only iDC expressed the activation molecule CD83. Treatment with rhIL-4 caused many MOMC to develop morphologic properties of dendritic cells within 96 h, but costimulatory molecule up-regulation and CD14 down-regulation were heterogeneous, and CD83 expression was infrequent. In contrast, calcium ionophore (CI) treatment induced rapid and consistent effects in MOMC from both healthy volunteers and cancer patients, including down-regulated CD14 expression, acquisition of dendritic cell morphologic properties, up-regulated MHC and costimulatory molecule expression, and de novo CD83 expression. Many such effects occurred within 20 h of treatment. CI treatment activated purified CD14+ monocytes and also enhanced the spontaneous activation of purified CD14-/dim iDC in culture. Unfractionated MOMC, purified monocytes, and purified iDC displayed equivalently enhanced T cell-sensitizing efficiency following CI treatment. CD4+ T cell sensitization to keyhole limpet hemocyanin and CD8+ T cell sensitization to MART-1 melanoma-associated peptide were achieved in a single culture stimulation. Therefore, circulating monocytes and iDC can be induced by CI to manifest properties of activated DC, providing large numbers of efficient, nontransformed autologous APC for T cell sensitization strategies.

Bone Marrow Cells↗

PubMed1997

Differential roles of IRS-1 and SHC signaling pathways in breast cancer cells.

Several polypeptide growth factors stimulate breast cancer growth and may be involved in tumor progression. However, the relative importance of diverse growth factor signaling pathways in the development and maintenance of the neoplastic phenotype is largely unknown. The activation of such growth factor receptors as the insulin-like growth factor I receptor (IGF-I R), erbB-type receptors (erbB Rs) and FGF receptors (FGF Rs) controls the phenotype of a model breast cancer cell line MCF-7. To evaluate the function of 2 post-receptor signaling molecules, insulin receptor substrate-1 (IRS-1) (a major substrate of the IGF-IR) and SHC (a common substrate of tyrosine kinase receptors), we developed several MCF-7-derived cell clones in which the synthesis of either IRS-1 or SHC was blocked by antisense RNA. In MCF-7 cells, down-regulation of IRS-1 by 80-85% strongly suppressed anchorage-dependent and -independent growth and induced apoptotic cell death under growth factor- and estrogen-reduced conditions. The reduction of SHC levels by approximately 50% resulted in the inhibition of monolayer and anchorage-independent growth but did not decrease cell survival. Importantly, cell aggregation and the ability of cells to survive on the extracellular matrix were inhibited in MCF-7/anti-SHC clones, but not in MCF-7/anti-IRS-1 clones. Cell motility toward IGF was not attenuated in any of the tested cell lines, but motility toward EGF was decreased in MCF-7/anti-SHC clones. Our results suggest that in MCF-7 cells: 1) both IRS-1 and SHC are implicated in the control of monolayer and anchorage-independent growth; 2) IRS-1 is critical to support cell survival; 3) SHC is involved in EGF-dependent motility; and 4) normal levels of SHC, but not IRS-1, are necessary for the formation and maintenance of cell-cell interactions.

Adaptor Proteins, Signal Transducing↗