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Biomedical subjects

T Liu

Publications and source records attributed to T Liu.

At least 109 records · Page 6Linked to original sources
PubMed2001

Heart emergency room: effective for both geriatric and younger patients.

OBJECTIVES: To compare the 30-day cardiac event rate between patients aged at least 60 years (geriatric group) with those younger than 60 (younger group), who were enrolled in an Emergency department-based chest pain centre management protocol. METHODOLOGY: This was a retrospective, cohort study done at the Centre for Emergency Care at the University of Cincinnati, from 1 Oct 1991 to 31 March 1999 (from Oct 1991 to Dec 1998: 9-hour protocol in use; from Jan 1999 to March 1999: 6-hour protocol in use). Patients, at least 25 years, with the chief complaint of non-traumatic chest pain were eligible for management in the unit. Exclusion criteria included acute ST-elevation or depression > 1 mm in 2 contiguous leads, haemodynamic instability or clinical syndrome consistent with unstable angina. Outcomes studied were disposition and cardiac events at 30-days (defined as acute myocardial infarction, congestive heart failure, ventricular fibrillation / tachycardia arrest, coronary artery bypass surgery or percutaneous transluminal coronary angioplasty). The protocol was the standard of care and enrolled patients underwent continuous ECG and ST-segment trend monitoring, serial CK-MB draws at 0, 3, 6 and 9 hours, followed by either a graded exercise stress test or a sestamibi myocardial perfusion scan (from Oct 1998). With the 6-hour protocol the 9-hour draws were omitted and the GXTdone 3 hours earlier. RESULTS: A total of 2491 patients were enrolled; 304 (12.2%) in the geriatric age-group. The mean age was 66.8+/-5.9 and 41.3+/-8.6 years respectively. There were 133 (43.8%) female patients in the geriatric group and 1170 (53.5%) in the younger group. There were no statistically significant differences between the groups in terms of prevalence of risk factors, but there was significant (p < 0.001) and ECG changes from the baseline (p = 0.0015). The geriatric patients were also not different from the younger ones in terms of GXT positive for ischaemia (10, 5.3% vs 42, 2.7%; p = 0.124), admission rates (61, 20.1% vs 321, 14.7%; p = 0.312), coronary care unit admissions (8, 2.6% vs 63, 2.9%; p = 0.418 and 30-day complication rate (10, 3.6% vs 46, 2.4%; p = 0.303). CONCLUSION: The ED-based chest pain unit represents an effective way for the risk-stratification and management of both geriatric and young patients with low-to-moderate risk of acute coronary events.

Adult↗
PubMed2001

[Typing of Streptococcus mutans (serotype C) by arbitrarily primed polymerase chain reaction].

OBJECTIVE: To study the relationship between genetic diversity within Streptococcus mutans (C), and dental caries. METHODS: One reference strain (GS5) was used to establish the suitability of primers and the initial AP-PCR conditions. Isolates of Streptococcus mutans (C) were obtained from 19 caries-free and 40 caries-active patients, and were originally isolated on mitis-salivarius-bacitracin agar. Totally 278 isolates were biochemically and serologically confirmed as Streptococcus mutans (C). Chromosomal DNA was extracted from those isolates by Chelex. One random primer, OPA-05 was used as a template in PCR reaction. All amplification reactions were conducted in a volume of 20 microliters containing 2 microliters of 10 x reaction buffer, 200 mumol/L each of dATP, dCTP, dGTP and dTTP and 2.5 units of Taq DNA polymerase. We varied the concentrations of MgCl2 (1.5-4.5 mmol/L), template DNA (2-40 ng), and primer (0.3-0.5 mumol/L) to determine the optical conditions for AP-PCR. The temperature profile in a thermocycler was 35 cycles as follows: 94 degrees C for 1 min, at 36 degrees C for 2 min, at 72 degrees C for 2 min. The initial denaturation was at 94 degrees C for 5 min and the final extension at 72 degrees C for 5 min. RESULTS: The MgCl2 concentration in 4 mmol/L and the primer concentration in 0.5 mumol/L produced clearly distinct and reproducible fingerprints. We found 105 different patterns among the 278 isolates. In high-caries persons more than one genotype isolates of Streptococcus mutans (C) were colonized. CONCLUSIONS: Isolates of Streptococcus mutans (C) exist apparent genetic diversity. The genotypes of isolates might relate to differences in caries susceptibility.

DNA, Bacterial↗
PubMed2001

Aortic and mitral valve replacement with retrograde perfusion in the beating heart.

OBJECTIVE: To estimate the value of aortic valves and combined mitral valve replacement with retrograde perfusion in beating hearts. METHODS: Continuous retrograde coronary sinus perfusion with beating hearts was used in 83 patients undergoing aortic valve or aortic valve combined with mitral valve replacement, without application of cardioplegia. After aortic valve replacement, the retrograde perfusion was changed to antegrade perfusion for mitral valve replacement or correction of the other deformities (group A). Cold blood cardioplegia solution (15 degrees C) was infused at intervals in 20 cases (group B). The following parameters were tested: lactate, ET, CTn-T and MDA in blood; myocardial ultra-structure; and cardiac rhythm and cardiac output (CO). RESULTS: All biochemical values increased after cardiopulmonary bypass (P < 0.05-0.01). Empty and beating heart sinus rhythm was maintained in group A. Myocardial ultrastructure did not change significantly. The pump was stopped smoothly as the surgical procedure finished. No postoperative low cardiac output syndrome or arrhythmia was observed. Eight-one patients recovered smoothly, two died from renal failure or infective shock. When the pump stopped, all patients in group B were supported by 5-10 micrograms.kg-1.min-1 dopamine. Transient pacing was used in 9 patients. One patient died from low cardiac output syndrome. CONCLUSION: This method is a good myocardial protection which simulates physiologic status. It is applicable to aortic valve and combined mitral valve replacement of patients with large heart or heart failure and long time aortic cross-clamping. Ideal clinical effect can be achieved.

Adolescent↗
PubMed2001

[Studies on the relationship between clinicopathological features and human papillomavirus types in female lower genital tract carcinoma].

OBJECTIVE: To investigate the relationship between clinicopathological features and human papillomavirus types in female lower genital tract carcinoma. METHODS: Clinicopathological features of 100 cases of female lower genital tract carcinoma (63 cervical carcinoma and 37 vulvar carcinoma) were studied retrospectively. Standard PCR (HPV type 6/11, 16, 18) was applied to formalin fixed, paraffin embedded sections. RESULTS: There were 54 cases of cervical carcinoma and 33 cases of vulvar carcinoma in the 87 cases of target DNA qualified samples. The HPV detection rate in cervical carcinoma was 83.3%. HPV16 (55.6%) and HPV 18(24.4%) were the predominant types. In vulvar carcinoma, HPVs, mainly HPV 16(70%, 7/10), were detected in basaloid (83.3%, 5/6) and warty carcinoma (83.3%, 5/6), but none in conventional type of keratinized squamous cell carcinoma (0.0%, 0/21). Three of the 6 women with basaloid carcinoma were associated with cervical squamous neoplasia, and the same HPV type was found in both lesions in 2 of the 3 patients with two primary tumors. Four patients with basaloid carcinoma recurred after simple vulvectomy or local excision, but no lymph node metastasis occurred and all were still alive at last follow-up, with a median follow-up of 6.3 years. In contrast, the majority of the women with keratinized squamous cell carcinoma were over 65 years of age, with histologic extensive keratinization and poorer prognosis. CONCLUSIONS: A high detection rate of HPV 16 and 18 was found in cervical carcinoma. However, the sensitivity of HPV in vulvar carcinoma seems to be more related to histologic type.

Adult↗
PubMed2001

[Apoptosis of myocardial cells in dilated cardiomyopathy].

OBJECTIVE: To study apoptosis of myocardial cells in dilated cardiomyopathy (DCM) and its relation with cardiac function. METHODS: Myocardial samples of 21 patients in a DCM group were obtained from hearts of 14 patients undergoing endomyocardial biopsy (EMB) in right ventricular (EMB sub-group) and from the hearts of the 7 remaining patients at autopsy (Autopsy sub-group). Myocardial samples of a control group were obtained from hearts of 5 patients at autopsy, who died of causes other than cardiovascular disease. Apoptosis was evaluated histochemically by in situ end-labeled DNA (Tunel method). RESULTS: (1) Apoptotic index (AI) of the DCM group was significantly higher than that of the control group(P < 0.01), AI of EMB sub-group was significantly lower than that of autopsy sub-group (P < 0.01), but significantly higher than that of the control group (P < 0.01). (2) AI in patients with heart-thorax ratio (HTR) < 0.6, left ventricular end diastolic diameter (LVDd) < 65 mm and left ventricular ejection fraction (LVEF) > or = 40% was significantly lower than that of patients with HTR > or = 0.6, LVDd > or = 65 mm and LVEF < 40% respectively (P < 0.01 for all), but was significantly higher than that of the control group respectively (P < 0.01 for all). CONCLUSIONS: Apoptotic myocardial cells were frequently observed in the myocardial tissues of the DCM and the magnitude of apoptosis increased with the deterioration of cardiac function, indicating that apoptosis may be an important mechanism of loss of myocardial cells and cardiac dysfunction in the DCM.

Adult↗
PubMed2001

[Clinicopathological analysis of 6 cases of diffuse panbronchiolitis].

OBJECTIVE: To study the clinical and pathological characteristics of diffuse panbronchiolitis (DPB). METHODS: Clinical history of six cases of DPB and their pathological slides were studied and analyzed. RESULTS: Diffuse panbronchiolitis was characterized by chronic recurrent nasosinusitis and pulmonary infection and respiratory bronchiolitis. Pathologically, all layers of the respiratory bronchiole walls were involved. Prominent chronic inflammation with lymphocytes, plasma cells and histiocytes infiltration was noted in all cases. In the lumens of the bronchioles, PMN or mucus could be identified. The chronic inflammatory cell infiltration also contained numerous foamy macrophages within the walls of the small bronchioles and in the stroma of the lung as well. Among the 6 cases of DPB, two cases were associated with thymoma. CONCLUSIONS: DPB is a distinct clinicopathological entity. Open lung biopsy or thorocoscopic biopsy is necessary for the correct diagnosis of clinical atypical DPB cases.

Adolescent↗
PubMed2001

Gynecological procedures under gasless laparoscopy.

OBJECTIVE: To evaluate gasless laparoscopy in treating gynecological conditions. METHODS: With Kirschner wire lifting, transversely or longitudinally introduced into abdominal wall subcutaneously, we exposed the operative field and pelvic organs with routine operative instruments under epidural anesthesia. When a dense pelvic adhesion was confronted, we used the temporarily low-pressured pneumolaparoscopy to dissect it. RESULTS: All procedures were carried out without organ injury, hematoma, or other complications. The operative field can be clearly seen with this method. The mean time for appendagectomy was one hour and for laparoscopic assisted vaginal hysterectomy 80 minutes. CONCLUSION: Gasless laparoscopy avoids the complications which occur in the routine laparoscopy such as subcutaneous or mediastinal pneumatoma, hypercarbonemia, air embolism, cardiopulmonary dysfunction. Our lifting method is simple, convenient, time and money saving, as well as more flexible for treating gynecological conditions.

Adult↗
PubMed2001

[Study on the relationship between leptin and neonatal weight and the expression of leptin in placenta].

OBJECTIVE: To investigate the relationship between the leptin level and neonatal weight and the expression of leptin in placenta. METHODS: The concentrations of leptin in 100 maternal blood and umbilical blood of the term pregnant women were examined by radioimmunoassay (RIA). According to the neonatal weight to divide into the large for gestational age (LGA) group 19 cases, the appropriate for gestational age (AGA) group 65 cases, the small for gestational age (SGA) 16 cases. The level of leptin mRNA in 41 placental tissue was examined by Reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: (1) The expression level of leptin mRNA in placenta was 0.97 +/- 0.04, which was positively related to the neonatal weight significantly (r = 0.43, P < 0.01). The expression level of the LGA group (1.01 +/- 0.03) was significantly higher than the AGA group (0.97 +/- 0.02), (P < 0.01). The expression level of the SGA group (0.93 +/- 0.03) was significantly lower than AGA group, (P < 0.01). (2) The concentration of leptin in maternal blood was (14.22 +/- 7.66) micrograms/L, which was not related to the neonatal weight (r = 0.11, P > 0.05). (3) The concentration of leptin in umbilical blood was (7.58 +/- 5.15) micrograms/L, which was positively related to the neonatal weight (r = 0.57, P < 0.01). The concentration of leptin of LGA group was significantly higher than that of AGA group, which was (7.40 +/- 4.45) micrograms/L (P < 0.01). The concentration of leptin of SGA group was (2.79 +/- 1.54) micrograms/L, significantly lower than that of AGA group, (P < 0.01). CONCLUSIONS: The level of leptin in umbilical blood and placenta is closely related to the growth state of fetus. The level of leptin in maternal blood is not related to the neonatal weight. The placenta of pregnant woman is an important resource of leptin.

Birth Weight↗
PubMed2001

[The malignant potential of ovarian atypical endometriosis].

OBJECTIVE: To investigate the malignant potential of ovarian atypical endometriosis and ovarian endometrioid adenocarcinoma. METHODS: 12 cases of ovarian endometroid adenocarcinoma with associated endometriosis were reviewed retrospectively. Microsatellite markers were used to detect the loss of heterozygosity on chromosome 10q23 in ovarian carcinoma and their coexisting endometriosis. RESULTS: Among the 12 cases, benign eosinophilic metaplasia was observed in 8 cases, 5 of which (41.7%) with atypia. In these 5 cases, a spectrum of benign-atypical endometriosis with a transition to endometrioid adenocarcinoma was identified, and common genetic lesions were also detected in 2 of the 5 atypical endometriosis and their coexisting carcinomas. CONCLUSION: Histological observations as well as the molecular genetic evidence indicate that ovarian atypical endometriosis may possess a precancerous potential or play a role in the pathogenesis of certain malignant ovarian cancers.

Adenocarcinoma↗
PubMed2001

[Detection of the expression of Smad4, transforming growth factor beta(1) and beta receptor II proteins in paraffin-embedded human pancreatic cancer tissues].

OBJECTIVE: To explore the relationships between Smad4, TGF beta1 and TbetaR II in the TGF-beta pathway and the possible mechanisms by which they effect pancreatic carcinoma. METHODS: The expression of Smad4, TGF beta1 and TbetaR II in paraffin embedded pancreatic carcinoma tissues was detected by using antibodies against Smad4, TGF beta1 and TbetaR II with EnVision immunohistochemistry. RESULTS: The positive rates of Smad4, TGF beta1 and TbetaR II were 58.93% (33), 66.07% (37) and 60.71% (34), respectively. The positive rates of the above three proteins in matched normal pancreatic tissues were 89.29% (50), 25.00% (14) and 25.00% (14) respectively. There was a significant relationship between the expression of TGF beta1, clinical stage and the metastasis of the tumor (P < 0.05). There was also a significant relationship between the expressions of TGF beta1 and TbetaR II (P < 0.05). CONCLUSIONS: The expression of Smad4 in pancreatic carcinoma tissue is significantly decreased but the expression of TGF beta1 and TbetaR II are increased. Smad4 may play an important role in the regulation of TGFbeta inducible gene expression and subsequent growth inhibition, but TGFbeta may also act in a Smad4-independent manner.

DNA-Binding Proteins↗
PubMed2001

Synthesis and anticancer activity of nordihydroguaiaretic acid (NDGA) and analogues.

Nordihydroguaiaretic acid (NDGA) 1 is a constituent of the creosote bush Larrea divaricata and is well known to be a selective inhibitor of lipoxygenases. NDGA can also inhibit the platelet derived growth factor receptor and the protein kinase C intracellular signalling family, which both play an important role in proliferation and survival of cancers. Moreover, NDGA induces apoptosis in tumour xenografts. Although it is likely to have several targets of action, NDGA is well tolerated in animals. These encouraging results have prompted interest in the compound for clinical study. However, high concentrations of NDGA are required for efficacy and more potent analogues are required. We have synthesized five analogues of NDGA with different lengths of carbon bridge between the two catechol moieties in order to establish the spacing required for optimum anticancer effect and to compare their activities with NDGA. In order to ascertain if the catechol moieties are essential for anticancer activity, we prepared five analogues of NDGA containing only one hydroxyl group on each aromatic ring. NDGA 1, its racemic form 2, the catechol derivatives 5, 6 with five or six carbon atom bridges and the phenol analogues 8-11 with bridges of three to six carbon atoms all showed similar activity, with IC50 values of approximately 3-5 microM against the H-69 small cell lung cancer cell line. Analogues with shorter (3) or longer bridges (7, 12) were much less active. The most potent analogue was the biscatechol with a four-carbon bridge 4 which was > 10 times more active than NDGA and therefore represents a new lead compound in this area. Surprisingly, the tetramethyl ether 14 of this compound was slightly more active than NDGA, but the trihydroxy analogue 13 was less active than NDGA. The conformationally restricted analogue 15 was also less active than NDGA. In summary, simplification of the structure of NDGA by removal of the methyl groups has produced a new lead compound 4, which is >10 times more potent than NDGA as a proliferative inhibitor of H-69 small cell lung cancer cells.

Antineoplastic Agents↗
PubMed2001

[Construction of eukaryotic expression plasmid pcDNA3-gtfB expressing glucosyltransferase B of Streptococcus mutans].

OBJECTIVE: Glucosyltransferase (GTF) of Streptococcus mutans is considered as a cariogenic virulence factor due to its ability to synthesize glucan, which facilitate sucrose-depended adherence and cell-to-cell accumulation of bacteria. In this study, gtfB, the target gene fragment which encodes multiple catalytic sites and antigen epitopes of GTF, was recombined into eukaryotic expression vector pcDNA3. The feasibility of the recombination plasmid pcDNA3-gtfB used as gene vaccine will be investigated in further study. METHODS: The target gene fragment gtfB (904-4578 bp) was obtained by standard PCR amplification while genome DNA of streptococcus mutans GS-5 was used as template. Then the PCR products were extracted and purified from low-melting temperature agarose. The gtfB and plasmid pcDNA3 were cut by Kpn I, Xho I, and the digested products were extracted and purified again for recombination. The purified gtfB and plasmid pcDNA3 were recombined by T4 DNA ligase, ligation products were transformed into competent cell, Escherichia coli JM109. Transformed colonies were screened by Ampr LB plate, then recombined plasmids were isolated and identified by restricted endonuclease cutting and Sanger dideoxy DNA sequencing. RESULTS: Identified by agarose gel electrophoresis, the target gene-gtfB obtained PCR amplification had the same molecular size (36 kb) as predicted. It was indicated that recombined plasmids contained inserted gtfB gene fragment by restricted endonuclease cut analysis, the sequencing data also indicated that inserted gtfB gene had correct DNA sequence and orientation according to DNA sequence of Streptococcus mutans GS-5 (gene bank M17361). CONCLUSION: Inserted gene-gtfB of recombined plasmid pcDNA3-gtfB encoded multiple catalytic sites and epitopes. It was proved that these epitopes had high immune antigenicity and that antiserum could significantly inhibit the synthesis of water-insoluble glucans and water-soluble glucan. In vitro adherence experiment also indicated that it could inhibit streptococcus mutans adherence to saliva-coated hydroxyapatite. Vector pcDNA3 was high expressing eukaryotic vector, and could stimulate antigen-representing cell. It was suggested that recombined plasmid pcDNA3-gtfB had high immune antigenicity and immune responsiveness, and this supported its use as gene vaccine candidates in the development of anti-caries vaccines.

Dental Caries↗
PubMed2001

[Effects of angiotensin II on the 3H-TdR incorporation and synthesis of collagen in cultured bovine trabecular meshwork cells].

OBJECTIVE: To investigate the effects of angiotensin II (Ang II) on the cell proliferation and collagen synthesis of bovine trabecular meshwork (TM) cells in vitro. It may probe into the mechanism of primary open-angle glaucoma(POAG). METHODS: (1) The bovine trabecular meshwork cells were cultured and identified by immunohistochemistry method(neuronal specific enolas, NSE, factor related antigan). The growing characteristics and morphological feature of cultured primary and passaged cells were observed by invered microscope and eletron-microscope; (2) Ang II(1 x 10(-7) mol.L-1 and 1 x 10(-8) mol.L-1) and angiotensin receptor type I (AT1) antagonist (losartan) were incubated with cultured TM cells. The cellular proliferation was measured by 3H-thymidine(3H-TdR) incorporation assay and collagen synthesis was indirectly professed though detects the hydroxyproline of medium with chemistry methods. RESULTS: The cells of bovine trabecular meshwork were cultured successfully. Most of them were epithelia type. Ang II increased the TM cells uptake of 3H-TdR and inhibited by losartan partially. Meanwhile the hydroxyproline of medium was increased correspondingly. CONCLUSION: Establishing the method of culturing bovine trabecular meshwork cells is an important method for researching the characteristics of TM cells. Ang II can induce the cell proliferation of bovine TM cells and increase the synthesis of collagen in vitro. The AT1 antagonist may inhibit this cell proliferation effect.

Angiotensin II↗
PubMed2001

[Investigation on genotype constitution of different Plasmodium vivax isolates and its geographical distribution in China].

OBJECTIVE: To investigate the population constitution and geographical distribution of Plasmodium vivax in China using molecular technique. METHODS: Blood-spot filter paper samples with related epidemiological data were collected from vivax malaria patients living in malarious area of 10 provinces (autonomous region) in China. Semi-nested- or nested-allelic-specific PCR genotyping method was used to identify CSP genotypes, families and types of Plasmodium vivax of each isolate from these patients. RESULTS: Of 384 field isolates of Plasmodium vivax, 258 temperate zone family strains were identified, including 14 allelic variant genotypes spreading among 10 sampling provinces; allelic variants sized less than 731 bp were only seen in 5 provinces in southern China; 79 tropical zone family strains including 5 genotypes were also distributed in 5 provinces of southern China south to 25 degrees N. lat; and 14 PV Type-2 strains including 2 genotypes were found in some areas of Hainan and Yunnan Provinces. In addition, 33 isolates from genotype-mixed infections were revealed. CONCLUSION: At present, area north to 25 degrees N. lat. of the country is the sole area prevalent for Plasmodium vivax family strains of temperate zone; there is overlapping distribution of P. v. of temperate zone family and tropical zone family of this parasite in the southern China south to 25 degrees N. lat; where the most complex isolate constitution is in Yunnan and Hainan Provinces, and PV Type-2 strains have been found in some areas of the two provinces. Besides, there were 2 groups of genotype with distinct geographic distribution feature within the temperate zone family.

Animals↗
PubMed2001

[Empty nose syndrome].

OBJECTIVE: The aim of this article is to present the concept of empty nose syndrome(ENS) and help ENT doctors take care of regular nasal turbinate surgery. METHODS: Fourteen patients who was diagnosed as ENS in our department were reviewed retrospectively. All patients had undergone various forms of nasal surgery (all had had turbinectomy). Their age ranged from 13 to 52 years. All patients were treated conservatively, among these patients 5 subjects who had more serious symptoms received submucous and subperiostal nasal implantation with ilium. RESULTS: All patients had nasal obstruction and dryness of nasal cavity, nasopharynx and oto-pharynx in 6 months--5 years after their first nasal surgery, some presented symptoms of depression. Nasoscope examination showed all patients had a cylindrically enlarged nasal cavity. Conservative treatment was effective in most cases. The effectiveness of operative treatment was encouraging during short-term follow-up. CONCLUSION: Extensive turbinectomy may cause secondary nasal mucosal atrophy and a series of subsequent symptoms. The presentation of this concept is to remind the ENT doctors prudently performing turbinectomy to avoid the occurrence of irreversible injury to the nasal cavity.

Adolescent↗
PubMed2001

[Expression and distribution of Aquaporin 1 in the nasal polyps].

OBJECTIVE: To confirm the expression and distribution of Aquaporin 1 (AQP1) in the nasal polyps and to investigate the relation between AQP1 and the nasal polyp edema. METHODS: fourteen cases of normal inferior turbinates and 26 cases of nasal polyps were used. The expression and distribution of AQP1 in nasal polyps were examined by immunohistochemical technique. RESULTS: The level of AQP1 in the epithelial cells and serous cells from nasal polyps was higher than that in inferior turbinates, and the level of AQP1 in the epithelial cells and cilium cells from inferior turbinate was higher than that in nasal polyps. CONCLUSION: There is close relationship between AQP1 and nasal polyp edema.

Adult↗