Biomedical subjects

Y Shi

Publications and source records attributed to Y Shi.

At least 253 records · Page 14Linked to original sources

PubMed2000

[Association of HLA-DRB1 allele and the susceptibility to alveolar echinococcosis in the west of China].

OBJECTIVE: To investigat the association of HLA-DRB1 alleles and the susceptibility to alveolar echinococcosis (AE). METHODS: Thirty-five patients with AE in the high prevalence areas in the west of China were investigated for HLA-DRB1 gene by PCR/SSP technique. The results were compared with 104 normal healthy peoples. RESULTS: Frequency of HLA-DRB1 * 040x was 26% in patient group, which was significantly higher than in control group (9.62%), with a relative risk (RR) of 4.45 (chi(2) = 13.67, P < 0.01), and with an etiological fraction of 0.20. Frequency of HLA-DRB1 * 0701 allele was decreased in patient group (patient 2.86%, control 13.94%; chi(2) = 6.67, P < 0.05), with preventable fraction of 0.30. While the frequencies of other DRB1 alleles were not significantly different. CONCLUSION: Susceptibility to AE is strongly associated with the HLA-DRB1 * 040x allele. The high prevalence of human AE in this region was associated with genetic factor. HLA-DRB1 * 0701 geners resistant to Echinococcus multilocularis metacestode infection.

Adolescent↗

PubMed2000

[Diagnosis and surgical treatment of temporal lobe epilepsy].

OBJECTIVE: To discuss the diagnosis and surgical treatment of temporal lobe epilepsy. METHODS: From 1995 to 1998, 30 patients with intractable mesial temporal lobe epilepsy were identified by EEG and MR. Among them, 15 patients underwent anterior temporal lobectomy, while another 15 patients accepted selective amygdalahippocampectomy. The results of operation and follow-up were analyzed. RESULTS: As to seizure outcome, all patients were benefited from surgery. Surgical result was satisfactory in 18 patients, notable in 11, and good in 1. There was no complication. CONCLUSIONS: MR is beneficial for the localization of epileptic foci. Operation is an effective way for the treatment of temporal lobe epilepsy. Selective amygdalohippocampus is the first choice for medial temporal lobe epilepsy. Transzygmatic-temporal lobe base approach improves the safety of operation.

Adolescent↗

PubMed2000

[Hemorrhagic shock increases the occurrence of bacterial translocation].

OBJECTIVE: To determine whether hemorrhagic shock (HS) increases the occurrence of bacterial translocation (BT). METHODS: 100 patients were divided into 4 groups: control group (group I, 34 patients); group with hemorrhagic shock (HS) caused by closed blunt abdominal trauma (group II, 23); group caused by closed blunt abdominal trauma without HS (group III 15); and group with HS caused by intra-abdominal viscus hemorrhage (group IV 28). Preoperative and postoperative samples were taken from peripheral blood, visceral peritoneal swab, portal vein blood, ileal mesenteric lymph node, liver and spleen biopsy respectively for aerobic and anaerobic culture. RESULTS: The positive culture rates of these groups were 6%, 65%, 13%, 68% respectively. The difference between the control and experimental groups was significant(P < 0.05). The difference was also significant between group I and II and between I and IV (P < 0.01), whereas it was not significant between I and III, and between II and IV (P > 0.05). CONCLUSION: HS increases the occurrence of BT.

Abdominal Injuries↗

PubMed2000

[Cause and management of dislocated nuclear fragments during phacoemulsification].

OBJECTIVE: To investigate the cause and management of posteriorly dislocated lens nucleus in the vitreous cavity during phacoemulsification. METHODS: The authors performed a retrospective study of 18 patients with dislocation of nuclear fragment into vitreous cavity during phacoemulsification at Tong Ren Hospital from August 1994 to January 1999. RESULTS: 4 cases with dislocated nuclei floated in the anterior vitreous were removed by a lens loop from limbal extensive incision. 2 cases with their dislocated nuclei less than 1/4 of the normal size were under follow-up for 3 - 4 years, and no complications were observed. The final outcome in 1 case with a dislocated nucleus half of its normal size was ocular atrophy as a result of phacoanaphylactic endophthalmitis. 11 cases underwent pars plana vitrectomy. In the operation the nuclei were floated anteriorly by injection of perfluoro-1, 3-dimethylcyclohexane, then they were removed by a lens loop through the limbus and in 2 cases they were fragmented by ultrasound. The main post-operative complication was corneal edema. The final visual acuities generally were improved in varying degrees in 1 month to 4 years of follow-up. CONCLUSIONS: During phacoemulsification, the dislocation of a nucleus is liable to first occur in the peripheral sculpting stage, and secondly in central sculpting stage. A radial tear extending posteriorly from a discontinuous anterior capsulorrhexis is the major risk factor predisposing to posterior dislocation of the nucleus or nuclear fragment. During phacoemulsification, vitrectomy should be performed as soon as possible for a nucleus dislocated into middle or posterior vitreous cavity, and it is a safe and effective method for management of dislocated nucleus.

Adult↗

PubMed2000

[The relationship between angiotensin converting enzyme gene polymorphism and risk factors for coronary heart disease].

OBJECTIVE: To explore the relationship between angiotensin converting enzyme (ACE) gene polymorphism and risk factors for coronary heart disease (CHD). METHODS: 148 patients with CHD and 159 unrelated healthy individuals were studied using polymerase chain reaction (PCR) and genetic methods. Risk factors of CHD were assessed by standard questionnaire, physical examination and blood tests. RESULTS: (1) There were no significant differences among genotypes in terms of years, sex, body mass index (BMI), systolic blood pressure, diastolic blood pressure, total cholesterol (TC), triglyceride (TG), low-density lipoprotein-cholesterol (LDL), high-density lipoprotein-cholesterol (HDL), HDL(2), HDL(3), apolipoprotein (Apo) AI, ApoB, and lipoprotein (a) [Lp (a)]. The prevalence rates of hyperlipidemia, hypertension (HT), cigarette smoking, diabetes mellitus (DM) and obesity were similar in the ACE genotypes (P > 0.05). (2) The DD genotype frequencies in low CHD risk groups, as defined by ApoB < 125 mg/dl and BMI <or= 24 kg/m(2), or TC < 230 mg/dl, TG < 200 mg/dl, LDL < 160 mg/dl and BMI <or=24 kg/m(2) without HT and DM were significantly higher than that in normal subjects (0.257, 0.315, 0.273 vs 0.157, chi(2) = 3.98, 7.80, 4.01, P < 0.05). CONCLUSION: There was no correlations between ACE gene polymorphism and the classic CHD risk factors noticed. ACE DD genotype seemed to be an independent risk factor for CHD in the Chinese population.

Asian People↗

PubMed2000

[Evaluation of modified maze procedure by Doppler tissue imager].

Since 1998 the cardiac surgeons of WCUMS have performed modified maze procedure for treating the patients with rheumatic mitral valve disease accompanied with chronic atrial fibrillation (Af). In this study, echocardiography, especially Doppler Tissue Imager (DTI), was used to evaluate atria contraction and function of such patients before and after the operation. 14 rheumatic mitral disease patients, aged 27-60 years, were chosen; among them, 11 had mitral stenosis, 3 mitral regurgitation. The control group consisted of 16 cases, aged 24-67 years, with normal echocardiogram. Before and half-1 year after the operation, left atrium, left ventricle, right atrium and ventricle were measured, and cardiac function and posterior wall motion of left atrium were measured. Velocity of mitral valve annual and tricuspid valve annual was measured in DTI. The results showed: There was no age difference between the two groups. The motion of posterior wall of left atrium was 4.18 +/- 0.37 mm in the operation group, 4.09 +/- 0.29 mm in the control group (P > 0.05). No difference in velocity of mitral/tricuspid valve annual between the two groups was observed; 3 peaks of mitral valve annual were S 0.11 +/- 0.02, e 0.11 +/- 0.01, a 0.09 +/- 0.01 (m/s) in operation group, and S 0.08 +/- 0.00, e 0.10 +/- 0.01, a 0.08 +/- 0.01 (m/s) in control group, (P > 0.05, respectively); 3 peaks of tricuspid valve annual were S 0.10 +/- 0.01 vs 0.11 +/- 0.08, e 0.11 +/- 0.08 vs 0.10 +/- 0.01, a 0.10 +/- 0.10 vs 0.09 +/- 0.01 (m/s), (P > 0.05, respectively). The diameter of left atrium after operation in cases of mitral stenosis decreased significantly, compared with that before operation (P < 0.01). The diameter of right atrium after operation decreased significantly, compared with that before operation (P < 0.01). There was no significant change in right ventricle/left ventricle/EF and FS. The diameter of left atrium after operation in cases of mitral regurgitation decreased significantly, compared with that before operation (P < 0.01). The diameter of left ventricle after operation decreased significantly, compared with that before operation (P < 0.05). No significant change in right ventricle/right atrium/EF and FS was noted. The authors conclude the DTI, as a new diagnostic method in echocardiography, has high sensitivity and is less influenced when used to observe motion of atrium-ventricle annual influenced. It can avoid the error caused by deviation of blood displacement. In the rheumatic mitral valve disease patients who had mitral valve replacement and modified maze procedure, atrial contraction respores, the risk of thromboembolism decreases and prognosis improves. So the operation is worth doing.

Adult↗

PubMed2000

[Preliminary echocardiographic evaluation on prosthetic valve replacement of preserving the subvalvular apparatus with artificial chorade for mitral stenosis].

The purpose of this study was to evaluate the preliminary results after prosthetic valve replacement of preserving the subvalvular apparatus with artificial chorade for mitral stenosis. 20 patients had received operation with expanded polytetrafluoroethylene(e-PTFE) as artificial chordade. The patients were followed up by means of echocardiography. The time of follow-up study varied from 4 to 18 months with a mean of 6 months. The left atrial, ventricular dimension as well as ventricular function were assessed. In addition, the length of artificial chorade and obstruction of left ventricular outflow track were observed. The results showed that left atrial diameter (LAD, from 57.59 +/- 13.51 mm to 47.05 +/- 9.55 mm), left ventricular end-diastolic dimension (LVEDD, from 46.23 +/- 12.56 mm to 42.41 +/- 10.86 mm), left ventricular end-systolic dimension (LVESD, from 33.50 +/- 10.20 mm to 29.68 +/- 8.40 mm) decreased (P < 0.01), and ejection fraction (EF, from 52.59 +/- 11.89% to 58.36 +/- 8.03%) increased (P < 0.05) after operation. There were no significant changes of fractional shortening (FS, from 29.23 +/- 8.99% to 31.05 +/- 6.08%). The length of artificial chorade ranged from 2.6 cm to 4.3 cm (the mean, 3.2 cm). There was no case of obstruction of left ventricular outflow track. It is believed that the result of preliminary echocardiographic observation on prosthetic valve replacement of preserving the subvalvular apparatus with artificial chorade for mitral stenosis is satisfactory.

Adult↗

PubMed2000

[Preparation of 131I-VIP and 131I-VIP receptor imaging].

This study was aimed at the preparation of 131I-vasoactive intestinal peptide (VIP) and its preliminary application in clinical imaging. VIP was labeled with Na 131I using chloramine-T method, then isolated by Sephadex G-10 column chromatography and examined by silica 60F254 thin layer chromatography. The bacteria and pyrogen were examined and the safety test was carried out. One control and two patients suffering from abdomen tumor were investigated. The results showed that the labeling rate of 131I was 80% and the specific activity of 131I-VIP was 36 TBq/mmol. The radiochemical purity of 131I-VIP was over 98%, and it decreased to 95% after six hours' storage at 4 degrees C. It was proved that the 131I-VIP eluate had no bacteria, no pyrogen and no poison. The injected 131I-VIP was distributed into the lungs immediately and was eliminated through kidneys. The primary tumor could be visualized about half an hour to 3 hours after injection. This study demonstrates that 131I-VIP is suitable for in vivo imaging and may be used as an effective tracer to identify the tumor site in patients with VIP receptor positive carcinoma.

Animals↗

PubMed2000

[The study of facial neurapraxia].

OBJECTIVE: To study the clinical characteristics and mechanism of facial neurapraxia. METHOD: Patients were tested with nerve excitability method and judged the degree of facial paralysis. Animal mode of neurapraxia was made and threshold of evoked electromyographic potential was tested. The fibers of facial nerve were observed under transmission electromicroscope. RESULT: Average restoration time of evoked electromyographic potential was 52.5 min. The lamellar separation of myelin sheath of facial nerve was found under electromicroscope. Patients with facial neurapraxia was judged as denervation negative and residual function of facial muscles was above 65%. CONCLUSION: Facial neurapraxia is mild reversible facial paralysis and relevant to the lamellar separation.

Animals↗

PubMed2000

[Analysis of trace elements in liver, spleen and brain of rats infected with Toxoplasma gondii].

OBJECTIVE: To study the level of five trace elements(Fe2+, Cu2+, Zn2+, Ca2+, Mg2+) in the liver, spleen and brain of the rats infected with Toxoplasma gondii. METHODS: 20 rats were randomly and equally divided into two groups: normal group and experimental group. On the 64th day after injection of 1.5 x 10(6) T. gondii/2 ml, all of the rats were killed and the atomic absorption method were used. RESULTS: Compared with the normal group, the level of Cu2+ in liver in experimental group was significantly reduced (P < 0.01), and the amount of Fe2+ of sick rats were higher than that of the normal (P < 0.01). No differences in the content of Zn2+, Ca2+, Mg2+ between the experimental and control group were determined; the level of Fe2+, Cu2+ in spleen in experimental group was significantly altered (P < 0.01). The amount of Mg2+ of sick rats were higher than that of the normal (P < 0.01), and no difference on the content of Zn2+, Ca2+ between the experimental and control group were estimated; the level of Fe2+, Cu2+, Mg2+ in brain in experimental group was significantly reduced (P < 0.01). The amount of Ca2+ of sick rats were higher than that of the normal (P < 0.02). No difference on the content of Zn2+ between the experimental and control group were estimated. CONCLUSION: T. gondii infection might cause changes in trace elements in the liver, spleen and brain of rats.

Animals↗

PubMed2000

[Relationship between tissue inhibitors of metalloproteinase and metastasis and prognosis in breast cancer].

OBJECTIVE: To investigate the clinical significance of tissue inhibitors of metalloproteinase (TIMP) -3 and TIMP-4 in human breast cancer. METHODS: The levels of TIMP-3 and TIMP-4 mRNA in paraffin-embedded breast carcinoma specimens from 70 patients with primary invasive breast cancer who had undergone radical mastectomy from January of 1984 to December of 1985 were assessed by in situ hybridization assay. Intratumoral microvessel density (MVD) and vascular endothelial growth factor (VEGF) expression were detected by the standard streptavidin biotin peroxides method. RESULTS: Both TIMP-3 and TIMP-4 mRNA expressions were higher in patients with axillary lymph node metastasis than in those without metastasis (P < 0.01), and patients with higher expression of any of these two genes had a better prognosis than those with lower expression (P < 0.01). We introduced lymph node status, TNM staging, MVD and VEGF expression, plus TIMP-3 and TIMP-4 to the Cox's proportional hazards regression model for significant analysis, and found that the TIMP-3, TNM staging and MVD play an important role in prognosis of this group. CONCLUSIONS: TIMP-3 and TIMP-4 are correlated with metastasis in breast cancer, and TIMP-3 demonstrates an independent prognostic factor for the patients. These results provide a valuable clue for developing new, practical prognosticators in breast cancer patients.

Breast Neoplasms↗

PubMed1999

Radial capillary array electrophoresis microplate and scanner for high-performance nucleic acid analysis.

The design, fabrication, and operation of a radial capillary array electrophoresis microplate and scanner for high-throughput DNA analysis is presented. The microplate consists of a central common anode reservoir coupled to 96 separate microfabricated separation channels connected to sample injectors on the perimeter of the 10-cm-diameter wafer. Detection is accomplished by a laser-excited rotary confocal scanner with four color detection channels. Loading of 96 samples in parallel is achieved using a pressurized capillary array system. High-quality separations of 96 pBR322 restriction digest samples are achieved in < 120 s with the microplate system. The practical utility and multicolor detection capability is demonstrated by analyzing 96 methylenetetrahydrofolate reductase (MTHFR) alleles in parallel using a noncovalent 2-color staining method. This work establishes the feasibility of performing high-throughput genotyping separations with capillary array electrophoresis microplates.

Electrophoresis, Capillary↗

PubMed1999

Specificity in transforming growth factor beta-induced transcription of the plasminogen activator inhibitor-1 gene: interactions of promoter DNA, transcription factor muE3, and Smad proteins.

Transforming growth factor beta (TGF-beta) regulates a broad range of biological processes, including cell growth, development, differentiation, and immunity. TGF-beta signals through its cell surface receptor serine kinases that phosphorylate Smad2 or Smad3 proteins. Because Smad3 and its partner Smad4 bind to only 4-bp Smad binding elements (SBEs) in DNA, a central question is how specificity of TGF-beta-induced transcription is achieved. We show that Smad3 selectively binds to two of the three SBEs in PE2.1, a TGF-beta-inducible fragment of the plasminogen activator inhibitor-1 promoter, to mediate TGF-beta-induced transcription; moreover, a precise 3-bp spacer between one SBE and the E-box, a binding site for transcription factor muE3 (TFE3), is essential for TGF-beta-induced transcription. Whereas an isolated Smad3 MH1 domain binds to TFE3, TGF-beta receptor-mediated phosphorylation of full-length Smad3 enhances its binding to TFE3. Together, these studies elucidate an important mechanism for specificity in TGF-beta-induced transcription of the plasminogen activator inhibitor-1 gene.

Base Sequence↗

PubMed1999

Neuralization of the Xenopus embryo by inhibition of p300/ CREB-binding protein function.

p300/ CREB-binding protein (CBP) is a transcriptional coactivator for a plethora of transcription factors and plays critical roles in signal transduction pathways. We report that the inhibition of p300/CBP function in the Xenopus embryo abolishes non-neural tissue formation and, strikingly, initiates neural induction and primary neurogenesis in the entire embryo. The observed neuralization is achieved in the absence of anterior or posterior gene expression, suggesting that neural fate activation and anterior patterning may represent distinct molecular events. We further demonstrate that the neuralizing and anteriorizing activities of chordin and noggin are separable properties of these neural inducers. This study reveals that all embryonic cells possess intrinsic neuralizing capability and that p300/CBP function is essential for embryonic germ layer formation and neural fate suppression during vertebrate embryogenesis.

Animals↗

PubMed1999

Crystal structure of the PTEN tumor suppressor: implications for its phosphoinositide phosphatase activity and membrane association.

The PTEN tumor suppressor is mutated in diverse human cancers and in hereditary cancer predisposition syndromes. PTEN is a phosphatase that can act on both polypeptide and phosphoinositide substrates in vitro. The PTEN structure reveals a phosphatase domain that is similar to protein phosphatases but has an enlarged active site important for the accommodation of the phosphoinositide substrate. The structure also reveals that PTEN has a C2 domain. The PTEN C2 domain binds phospholipid membranes in vitro, and mutation of basic residues that could mediate this reduces PTEN's membrane affinity and its ability to suppress the growth of glioblastoma tumor cells. The phosphatase and C2 domains associate across an extensive interface, suggesting that the C2 domain may serve to productively position the catalytic domain on the membrane.

Amino Acid Sequence↗

PubMed1999

Fast repair of hydroxy radical purine deoxynucleotide adducts by phenylpropanoid glycosides and their derivatives from Chinese herbs.

DNA damaged by oxygen radicals has been implicated as a causative event in a number of degenerative diseases, including cancer and aging. So it is very significant to look for ways in which either oxygen radicals are scavenged prior to DNA damage or damaged DNA is repaired to supplement the cells' inadequate repair capacity. The repair activities and reaction mechanism of phenylpropanoid glycosides (PPGs) and their derivatives, isolated from Chinese folk medicinal herbs, towards both dGMP-OH* adducts and dAMP-OH* adducts were studied with the pulse radiolytic technique. On pulse irradiation of nitrous oxide saturated 2 mM dGMP or dAMP aqueous solution containing one of the PPGs or their derivatives, the transient absorption spectra of the hydroxyl adduct of dGMP or dAMP decayed with the formation of that of phenoxyl radicals of PPGs or their derivatives within several decades of microseconds after electron pulse irradiation. The result indicated that dGMP or dAMP hydroxyl adducts can be repaired by PPGs or their derivatives. The rate constants of the repair reactions were deduced to be 0.641-1.28 x 10(9) M(-1) s(-1) for dGMP-OH* and 0.2-0.491 x 10(9) M(-1) s(-1) for dAMP-OH*, which positively correlated to the number of phenolic hydroxyl groups in the glycoside structure. A deeper understanding of this new repair mechanism may help researchers to design strategies to prevent and/or intervene more effectively in free radical related diseases.

DNA Adducts↗

PubMed1999

Fast repair of deoxynucleotide radical cations by phenylpropanoid glycosides (PPGs) and their analogs.

The repair effects on deoxynucleotide radical cations of phenylpropanoid glycosides (PPGs) and their analogs, isolated from a Chinese folk medicinal herb, were studied using the pulse radiolysis technique. The radical cations of deoxynucleotides were formed by the reaction of SO4*- with deoxynucleotides. On pulse irradiation of a nitrogen saturated deoxynucleotide aqueous solution containing 20 mM K2S2O8, 200 mM t-BuOH and one of the PPGs or their analogs, the transient absorption spectra of the radical cations of nucleotide decayed with the formation of those of the radical cation of PPGs or their analogs within several tens of microseconds after electron pulse irradiation. The result indicates that deoxynucleotide radical cations can be repaired by PPGs or their analogs. The rate constants of the repair reactions were determined to be 0.48-1.1 x 10(9), 0.64-1.80 x 10(9) and 2.12-4.4 x 10(9) M(-1) s(-1) for dAMP, dGMP and dCMP radical cations respectively. It is obvious that the rate constants of the repair reaction depend on the number of phenolic hydroxyl groups contained in the PPGs and their analogs. A deeper understanding of this new repair mechanism will undoubtedly help researchers design strategies to prevent and/or intervene more effective in free radical related diseases.

Cations↗

PubMed1999

Ligation of CD28 in vivo induces CD40 ligand expression and promotes B cell survival.

Functional activation of T cells requires ligation of Ag receptors with specific peptides presented by MHC molecules on APCs concurrent with appropriate contacts of cell surface accessory molecules. Among these accessory molecules, interactions between CD28/CTLA-4 with B7 family members (CD80 and CD86) and CD40 with CD40 ligand (CD40L) play a decisive role in regulating the progression of balanced immune responses. However, most information regarding the role of accessory molecules in immune responses has been derived in the context of signals from the TCRs. Little understanding has been achieved regarding the consequence of ligation of costimulation molecules in absence of signals from the TCR. By employing an in vivo murine system, we show, herein, that ligation of CD28 alone with anti-CD28 Abs leads to a dramatic enlargement of the peripheral lymphoid organs characterized primarily by the expansion of B cells. B cells from anti-CD28-treated mice are resistant to spontaneous and anti-IgM-induced apoptosis. These cells are also unsusceptible to FasL-mediated apoptosis. Interestingly, this in vivo effect of CD28 on B cells is largely mediated by inducing the expression of CD40L, since coadministration of a blocking Ab against CD40L inhibited CD28-mediated B cell survival and expansion. Therefore, CD28-mediated expression of CD40L may play an important role in the regulation of lymphocyte homeostasis.

Animals↗