Biomedical subjects

R Tang

Publications and source records attributed to R Tang.

At least 55 records · Page 3Linked to original sources

PubMed2001

Identification of a human LNX protein containing multiple PDZ domains.

Recently PDZ domains have been recognized as crucial organizers of protein complexes at the plasma membrane. Here we report the cloning of a novel 3.7-kb cDNA LNX from a human fetal brain cDNA library. The deduced amino acid sequence shares about 88% identity with the p70 form of Lnx, which is the mouse ligand of Numb protein X. Motif analysis reveals five protein-interaction modules conservative to those in the Lnx protein, including four PDZ domains and a NPXY motif for binding of the Numb PTB domain. Northern blot analysis shows that the length of the transcript in brain is distinct from those in other tissues. By radiation hybrid mapping, we localize the LNX gene to human chromosome 4q12 between marker D4S1577 and marker D4S1594. We predict that LNX may be important for the organization of signaling complexes in Numb-involved pathways or pathways regulated by other PTB-containing proteins.

Amino Acid Motifs↗

PubMed2001

A novel human hydroxysteroid dehydrogenase like 1 gene (HSDL1) is highly expressed in reproductive tissues.

We report the cloning and characterization of a novel human hydroxysteroid dehydrogenase like gene (HSDL1) located on human chromosome 16q24.2. The HSDL1 cDNA is 3407 base pair in length, encoding a 309 amino acid polypeptide related to human 17beta-HSD3. Northern blot reveals that the HSDL1 is highly expressed in testis and ovary. In situ hybridization indicates that the expression of HSDL1 is predominantly increased in the prostate cancer tissue compared with the normal prostate tissue, which suggests that the gene expression is important to the arising of prostate cancer.

Amino Acid Sequence↗

PubMed2001

Cell cycle regulatory protein expression in fresh acute myeloid leukemia cells and after drug exposure.

Characteristics of treatment-induced cell cycle arrest are important for in vitro and in vivo sensitivity of acute myeloid leukemia (AML) cells to cytotoxic drugs. We analyzed the expression of the major G1 cell cycle regulators (p21Cip1, p27Kip1, cyclins D, cyclin E and pRb) in 41 fresh AML cell samples. The level of p27 expression was the only factor correlated with the response to chemotherapy, a high level of p27 expression being predictive of complete remission. There was a close relation between expression of pRb, cyclin D2 and FAB subtype, illustrated by the absence of both proteins in most samples having a monocytic component (M4, M5). We also assessed the expressions of pRb, cyclin E, p21 and p27 and the activity of cdk2, the major regulator of S-phase entry, after exposure to cytosine-arabinoside (AraC) and daunorubicin (DNR), and found these proteins could characterize time- and dose-dependent cellular response to each drug. We observed hyperphosphorylated pRb, increased levels of cyclin E and a high cdk2 activity, but no p21 induction, in AML cells exposed to 10(-6) M AraC. After exposure to 10(-5) M AraC, corresponding to the serum concentration reached in high-dose AraC regimens (HDAraC), a strong p21 induction was observed, associated with similarly overexpressed cyclin E and even higher cdk2 activity than after 10(-6) M AraC, while apoptosis was significantly increased. These data suggest that cdk2 activity is likely to play a role in AraC-induced apoptosis in AML cells. This mechanism may account for high efficacy of HDAraC in cells showing little sensitivity to conventional AraC doses.

Apoptosis↗

PubMed2001

Risk factors for surgical site infection after elective resection of the colon and rectum: a single-center prospective study of 2,809 consecutive patients.

OBJECTIVE: To identify the risk factors for surgical site infection (SSI) in patients undergoing elective resection of the colon and rectum. SUMMARY BACKGROUND DATA: SSI causes a substantial number of deaths and complications. Determining risk factors for SSI may provide information on reducing complications and improving outcome. METHODS: The authors performed a prospective study of 2,809 consecutive patients undergoing elective colorectal resection via laparotomy between February 1995 and December 1998 at a single institution. The outcome of interest was SSI, which was classified as being incisional or organ/space with or without clinical leakage. A likelihood ratio forward regression model was used to assess the independent association of variables with SSIs. RESULTS: The overall SSI, incisional SSI, and organ/space SSI with and without clinical anastomotic leakage rates were 4.7%, 3%, 2%, and 0.8%, respectively. Risk factors for overall SSI were American Society of Anesthesiology (ASA) score 2 or 3 (odd ratio [OR] = 1.7), male gender (OR = 1.5), surgeons (OR = 1.3-3.3), types of operation (OR = 0.3-2.1), creation of ostomy (OR = 2.1), contaminated wound (OR = 2.9), use of drainage (OR = 1.6), and intra- or postoperative blood transfusion (1-3 units, OR = 5.3; >/=4 units, OR = 6.2). However, SSIs at specific sites differed from each other with respect to the risk factors. Among a variety of risk factors, only blood transfusion was consistently associated with a risk of SSI at any specific site. CONCLUSIONS: In addition to ASA score and surgical wound class, blood transfusion, creation of ostomy, types of operation, use of drainage, sex, and surgeons were important in predicting SSIs after elective colorectal resection.

Adolescent↗

PubMed2001

Molecular cloning and characterization of a novel peptidylprolyl isomerase (cyclophilin)-like gene (PPIL3) from human fetal brain.

During the large-scale sequencing analysis of a human fetal brain cDNA library, we isolated two cDNA clones encoding two novel proteins, which show 52% and 72% identity to the cyclophilin isoform 10 of C. elegans, respectively. Sequence analysis revealed these two cDNA clones are two different splicing variants of a novel cyclophilin-like gene (PPIL3). The PPIL3 gene was identified on a completely sequenced BAC (GenBank accession AC005037) from chromosome 2q33 between STS markers stSG2762 (proximal) and SHGC-3074 (distal), oriented toward the telomere. The PPIL3 gene consisted of eight exons spanning more than 18 kb of genomic DNA. RT-PCR analysis indicated that PPIL3 was ubiquitously expressed in adult human tissues.

5' Untranslated Regions↗

PubMed2001

Remnant lipoproteins are related to intima-media thickness of the carotid artery independently of LDL cholesterol and plasma triglycerides.

Remnants of triglyceride-rich lipoproteins (TRL) have been implicated in the early development of atherosclerosis. We tested this hypothesis by quantifying the plasma concentration of remnant-like particle cholesterol (RLP-C) in a cohort of healthy 50-year-old men in whom the common carotid artery intima-media thickness (CCA-IMT) was assessed by B-mode ultrasound as a surrogate marker for atherosclerosis. The subjects were given a fat-rich meal to study the generation of RLP-C during postprandial lipemia. Fasting plasma RLP-C and other major fasting plasma lipids and lipoproteins were determined twice, and the mean RLP-C concentration was strongly correlated with CCA-IMT (r = 0.32, P = 0.002). In addition, low density lipoprotein (LDL) cholesterol (r = 0.25, P = 0.01) and plasma triglycerides (r = 0.20, P = 0.05) were significantly related to CCA-IMT. Multivariate analyses showed a triglyceride-independent contribution of RLP-C to CCA-IMT. After fat intake, the median plasma RLP-C concentration was doubled after 3 h. The increase was strongly related to the postprandial generation of TRL apolipoprotein (apo)B-48, and large (S(f) 60;-400) TRL apoB-100. The association with CCA-IMT was somewhat stronger for the 3-h RLP-C level than for the fasting RLP-C concentration [r = 0.27, P < 0.01 (3 h) compared with r = 0.22, P < 0.05 (0 h)]. We conclude that the plasma concentration of RLP-C is related to CCA-IMT, independent of plasma triglycerides and LDL cholesterol, in a healthy middle-aged male population. - Karpe, F., S. Boquist, R. Tang, G. M. Bond, U. de Faire, and A. Hamsten. Remnant lipoproteins are related to intima-media thickness of the carotid artery independently of LDL cholesterol and plasma triglycerides. J. Lipid Res. 2001. 42: 17;-21.

Apolipoproteins↗

PubMed2001

[Application of computer image process to the research on the contact characteristics of subtalar joint].

With the use of computer image processing technology, a new method was proposed for studying the contact characteristics of the subtalar joint. The results showed the total subtalar articulation area was 9.52 +/- 0.40 cm2. On neutral position and under 600 N load, the contact area of the subtalar joint was 2.00 +/- 0.11 cm2. The contact area of the posterior articulation was significantly larger than that of the anterior and medial articulation (p < 0.01). The average contact pressure was 19.3 +/- 1.38 N, the force transmitted by the subtalar was 389.16 +/- 28.75 N, which accounted for about 64.86% of the applied shank load (600 N), and 69.39% of the force was transmitted by the posterior articulation. The posterior articulation plays an important role in the load. The fracture line of the calcaneus often appears in this area.

Adult↗

PubMed2001

[Clinical application and evaluation of polymerase chain reaction-microwell plate hybridization assay in the detection of Mycobacterium tuberculosis].

OBJECTIVE: To evaluate the clinical application and feasibility of polymerase chain reaction-microwell plate hybridization assay in the detection of Mycobacterium tuberculosis. METHODS: 1130 specimens with strong suspicion for mycobacterium tuberculosis were collected from the hospitals and were detected by fast bacilli stain, culture, PCR-electrophoresis and PCR-microwell plate hybridization respectively. The laboratory results were analyzed in combination with the symptoms and signs of patients and the observations on treatment. Also detected were 100 samples from the clinically evidenced non-tuberculosis patients. RESULTS: In the 100 samples collected from the patients without tuberculosis, the PCR-hybridization method and culture method did not detect Mycobacterium tuberculosis, but the fast bacilli stain method and PCR-electrophoresis method brought out one and two false-positive results respectively. The results of testing the 1030 clinical samples which probably contained Mycobacterium tuberculosis demonstrated that the PCR-hybridization method had the highest positive rate (481/1030) among the four methods, and the positive rates of the other three methods were PCR-electrophoresis (406/1030), culture (365/1030) and fast bacilli stain (256/1030) in proper order. The chi-square test showed that there were significant difference between the PCR-hybridization method and the other three methods respectively (P < 0.0083 or P < 0.0017). CONCLUSION: PCR-Hybridization method is specific, sensitive, accurate and fast in detecting mycobacterium tuberculosis; it is worthy to be used clinically.

Evaluation Studies as Topic↗

PubMed2000

Recombinant respiratory syncytial viruses with deletions in the NS1, NS2, SH, and M2-2 genes are attenuated in vitro and in vivo.

Respiratory syncytial virus (RSV) encodes several proteins that lack well-defined functions; these include NS1, NS2, SH, and M2-2. Previous work has demonstrated that NS2, SH, and M2-2 can each be deleted from RSV genome and thus are considered as accessory proteins. To determine whether RSV can replicate efficiently when two or more transcriptional units are deleted, we removed NS1, NS2, SH, and M2-2 genes individually and in different combinations from an infectious cDNA clone derived from human RSV A2 strain. The following six mutants with two or more genes deleted were obtained: DeltaNS1NS2, DeltaM2-2SH, DeltaM2-2NS2, DeltaSHNS1, DeltaSHNS2, and DeltaSHNS1NS2. Deletion of M2-2 together with NS1 was detrimental to RSV replication. It was not possible to obtain a recombinant RSV when all four genes were deleted. All of the double and triple deletion mutants exhibited reduced replication and small plaque morphology in vitro. Replication of these deletion mutants was more reduced in HEp-2 cells than in Vero cells. Among the 10 single and multiple gene deletion mutants obtained, DeltaM2-2NS2 was most attenuated. DeltaM2-2NS2 formed barely visible plaques in HEp-2 cells and had a reduction of titer of 3 log(10) compared with the wild-type recombinant RSV in infected HEp-2 cells. When inoculated intranasally into cotton rats, all of the deletion mutants were attenuated in the respiratory tract. Our data indicated that the NS1, NS2, SH, and M2-2 proteins, although dispensable for virus replication in vitro, provide auxiliary functions for efficient RSV replication.

Animals↗

PubMed2000

Analogs of lactam derivatives of alpha-melanotropin with basic and acidic residues.

A role of the aromatic and of the basic residues of the potent agonist (MTII) and antagonist (SHU9119) at the human melanocortin receptors 4 in the formation and stabilization of ligand-receptor complexes was examined. Analogs of MTII and SHU9119 with glutamic acid replacing one amino acid at a time were synthesized and tested for their ability to bind to and activate human melanocortin receptors 3, 4, and 5. Replacement of Phe (Nal) or Trp with Glu resulted in analogs of MTII and SHU9119 which were practically inactive at the receptors studied. The rather large (and unexpected) tolerance toward the presence of Glu in the position of His or Arg of MTII and SHU9119 clearly suggested that in the ligand receptor complexes these basic residues are not in contact with the receptors but probably face the extracellular environment. This identified the aromatic residues of MTII and SHU9119 as the primary structural features determining interactions of the agonist/antagonist with hMCR3-5.

Amino Acid Sequence↗

PubMed2000

Acceptability of serum screening as an alternative to cytogenetic diagnosis of down syndrome among women 35 years or older in Hong Kong.

The addition of second trimester serum markers to maternal age increases the efficacy of screening for Down syndrome by maternal age alone. Among women aged 35 years or older, serum screening makes a large proportion of amniocentesis unnecessary. However, there are ethical and medicolegal concerns about serum screening in 'old' women, largely because some of the pregnancies affected by Down syndrome and other chromosomal abnormalities may not be detected. We investigated the acceptability of serum screening in women aged 35 years or older when it was offered as an alternative to prenatal cytogenetic diagnosis after detailed counselling. Women referred for prenatal diagnosis of Down syndrome because of advanced maternal age were given the options of cytogenetic diagnosis by chorionic villus sampling (CVS) or amniocentesis. As an alternative, they could choose to undergo second trimester serum human chorionic gonadotrophin (hCG) and alpha-fetoprotein (AFP) screening first before deciding on whether to undergo amniocentesis. Between January 1997 and October 1999, 3419 subjects were recruited. 1807 women (52. 9%) chose to undergo serum screening, 1516 women (44.3%) chose to have amniocentesis and 96 women chose to have CVS (2.8%). The proportion of women who chose serum screening rose steadily from 38. 8% in the year of 1997 to 63.4% in 1999. Significantly fewer Chinese women chose serum screening than non-Chinese. The decision as to whether to undergo an invasive diagnostic procedure or to be content with the relatively safer but less accurate screening test varies, being affected by the women's background and culture.

Adult↗

PubMed2000

Surgical outcome after curative resection of rectal leiomyosarcoma.

PURPOSE: The aim of this study is to present the prognosis and possible associated prognostic factors after curative resection of rectal leiomyosarcoma. METHODS: From 1979 to 1996 our hospital saw 40 patients with rectal leiomyosarcoma, including 19 females, who did not have metastasis initially and received curative resection and regular postoperative follow-up. RESULTS: The mean age of the 40 patients was 58.7 years. Anal bleeding and perianal pain were the two most common symptoms at initial diagnosis. Twenty-nine patients received a radical surgical resection, such as abdominoperineal resection or low anterior resection; the other 11 patients received a wide local excision, such as transrectal excision or Kraske's operation. Sixteen tumors were classified as high-grade leiomyosarcoma, and 23 as low grade. Nineteen patients (48 percent) developed recurrence or metastasis postoperatively (median follow-up, 35 months). The overall and disease-free (1-year, 3-year, and 5-year) survival rates were 97, 90, and 75 percent and 90, 59, and 46 percent, respectively. In univariate analysis, younger group (<50 years, n = 9, P = 0.033) and high-grade leiomyosarcoma (P = 0.043) showed poorer prognosis in the disease-free survival curve. In the multivariate Cox model, gender, tumor size, tumor location, and operation type did not significantly affect disease-free survival, whereas histologic grade (P = 0.037) and age divided by a level of 50 years (P = 0.009) were shown to be independent factors. There was a strong trend toward higher local recurrence rate for the wide local excision group than for the radical resection group (55 vs. 24 percent, P = 0.067) despite the wide local excision group being composed of smaller tumors (5.1 vs. 7.5 cm, P = 0.069). There was no difference in the incidence of distant metastasis between the two groups with different operation types. The metastasis rates of the wide local excision and radical resection groups were 27 and 38 percent, respectively. CONCLUSION: A younger age (<50 years) and a high histologic grade of tumor were the two most significant poor prognostic factors for rectal leiomyosarcoma. Radical resection may be superior to wide local excision in the prevention of local recurrence but not distant metastasis.

Adult↗

PubMed2000

Primary colorectal lymphoma.

PURPOSE: The purpose of this study was to review the clinical presentation and characteristics of primary colorectal lymphoma, analyze the prognostic factors, and assess the results of treatment with adjuvant chemotherapy. METHODS: We identified 37 cases at our institution between 1980 and 1996. They comprised 0.48 percent of all cases of colon malignancies (37/7,658) during this period. The following clinical information was obtained: age, gender, signs and symptoms, tumor site, tumor size, histology grade, pathology, and adjuvant chemotherapy. RESULTS: The most common presenting signs and symptoms were abdominal pain (62 percent), abdominal mass (54 percent), and weight loss (43 percent). The most frequent site of involvement was the cecum (45 percent). Histologically, 29 (78 percent) were classified as high-grade, and 8 (22 percent) as intermediate-grade-to-low-grade lymphoma. Nine (24.3 percent) of the cases were Stage EI, 23 (62.2 percent) were Stage EII, and 5 (13.5 percent) were Stage EIV. Twenty-one (57 percent) cases received adjuvant chemotherapy. The five-year survival rate was 33 percent for all patients and 39 percent for patients treated with combination chemotherapy. Overall median survival time was 24 months and 36 months for those with adjuvant chemotherapy. Only histology grade, among the factors examined, was a significant prognostic factor for survival. The mean survival time of the patients with Stage II disease who received chemotherapy was 117.4 months, and it was 47.9 months for the patients with Stage II disease who did not received chemotherapy. CONCLUSIONS: In our retrospective study high-grade lymphoma was the only significant adverse prognostic factor for survival. Receiving adjuvant chemotherapy significantly improved survival in patients with Stage II disease. Patients with diffuse large-cell type had better survival than patients with small noncleaved-cell type in Stage II high-grade lymphoma.

Adult↗

PubMed2000

Colon carcinoma with synchronous ovarian metastasis--report and discussion of five cases.

Ovarian metastasis may present at the time of initial diagnosis of colon carcinoma or as a later recurrence. Little meaningful information is available regarding the treatment and outcome of synchronous ovarian metastasis of colon carcinoma. This report describes the clinical course of five patients with synchronous ovarian metastasis of colon carcinoma who were treated with aggressive surgery and chemotherapy. The treatment consisted of maximal surgical debulking followed by systemic chemotherapy with weekly 24 h infusion of high-dose 5-fluorouracil and leucovorin. All of the five patients had subsequent disease-free periods ranging from 6 to 43+ months following operation. Two of the patients who had no or minimal peritoneal involvement were still alive without disease at 33 and 43 months. The data from these cases suggest that aggressive surgery and systemic chemotherapy may be highly efficacious in the treatment of colon carcinoma with synchronous ovarian metastasis. Maximal debulking followed by chemotherapy may be particularly effective in those patients with minimal peritoneal involvement.

Adenocarcinoma↗

PubMed2000

Baseline reproducibility of B-mode ultrasonic measurement of carotid artery intima-media thickness: the European Lacidipine Study on Atherosclerosis (ELSA).

BACKGROUND AND OBJECTIVE: The European Lacidipine Study of Atherosclerosis (ELSA) is a prospective, randomized, double-blind, multi-national interventional trial to determine the effect of four-year treatment using the calcium antagonist lacidipine versus the beta-blocker atenolol on the progression of carotid atherosclerosis in 2259 asymptomatic hypertensive patients. B-mode ultrasound is used to measure the primary and secondary endpoints including the mean maximum intima-media thickness (IMT) of the carotid bifurcations and the common carotid arteries (CBM(max)), the mean maximum IMT of 12 standard carotid sites (M(max)) and the overall maximum IMT (T(max)). This paper reports the cross-sectional reproducibility of ultrasound measurements at baseline. METHOD: To evaluate measurement reliability, each patient is scanned twice at baseline and again at four annual visits, with 80% of the replicate scans performed by the same sonographer and 20% by a different sonographer; 50% of the replicate scans are read by the same reader and the other 50% by different readers. RESULTS: The overall coefficient of reliability (R) was 0.859 for CBM(max), 0.872 for M(max) and 0.794 for T(max). The reliability for CBM(max) was stable during the 1 3/4-year baseline period (R = 0.848 to 0.953) and was uniform among the 23 field centres (R = 0.798 to 0.926). Intra- and inter-reader reliability were 0.915 and 0.872 respectively, and intra-sonographer reliability was 0.866. CONCLUSION: The results demonstrate that by implementing standardized protocols and strict quality control procedures, highly reliable ultrasonic measurements of carotid artery IMT can be achieved in large multi-national trials.

Adrenergic beta-Antagonists↗

PubMed2000

[Detection of differentially expressed genes in hepatocellular carcinoma using DNA microarray].

Large scale gene expression profiles between normal hepatocytes and hepatocellular carcinomas are detected with high throughput microarray. DNA microarrays were made by spotting PCR products of 4,096 human cDNAs onto a specially treated glass slides. The probes were prepared by labelling normal tissue mRNA and cancer tissue mRNA with Cy3-dUTP and Cy5-dUTP separately through reverse transcription. The arrays were then hybridized against the cDNA probe mixture and the fluorescent signals were scanned. The obtained data were analyzed from 4 repeated experiments. There are 903 genes of which the average ratios between Cy3 signal and Cy5 signal are greater than 3.0. These genes identified through this approach are potential candidates for hepatocellular carcinoma diagnosis and therapy.

Carcinoma, Hepatocellular↗

PubMed2000

[Etiological study on patients with seronegative viral hepatitis].

OBJECTIVE: To investigate the etiology of hepatitis patients who were seronegative for viral hepatitis A through E. METHODS: By using PCR, HBV DNA, HCV RNA, HEV RNA and HGV RNA were detected in sera of 104 patients with seronegative viral hepatitis. The partial nucleotide sequences of 2 HCV and 17 HEV isolates were analysed by direct sequencing. RESULTS: Among the 104 patients with seronegative viral hepatitis, the positive rates of HBV DNA, HCV RNA, HEV RNA and HGV RNA were 29.8%, 3.8%, 22.1% and 7.7%, respectively, with only 38 cases (36.6%) negative for the genome of all known hepatitis viruses. CONCLUSION: In addition to serological tests, the polymerase chain reaction of all known hepatitis viruses should be used to make the diagnosis of non-A - E hepatitis.

Base Sequence↗

PubMed1999

[The treatment effect of ribavirin to hemorrhagic fever with renal syndrome on the kinetics of serum creatine phosphate kinase isoenzyme].

OBJECTIVE: To study the effect of ribavirin treatment on kinetics of serum creatine phosphate kinase isoenzyme(CK-MB) of patients with hemoarrhagic fever with renal syndrome(HFRS). METHODS: CK-MB levels in 155 HFRS patients treated with larger dose of ribavirin and with routine therapeutic dose were observed dynamicaly, using randomly controlled double-blind method. In addition, CK-MB levels in different disease phases and different clinical types of HFRS were compared. RESULTS: The results showed that CK-MB levels were significantly increased in febrile phase and decreased gradually to normal during convalescent phase in both groups, but in febrile phase, CK-MB levels in ribavirin-treated group and control group were 55.25 +/- 18.25 IU/L and 69.63 +/- 23.52 IU/L, respectively, the treated group had a lower level (P < 0.05). The severe and critical group treated by ribavirin showed a lower CK-MB level of 47.74 +/- 24.82 IU/L, while the control group showed a higher level of 66.08 +/- 25.01 IU/L(P < 0.05). CONCLUSION: These results indicated that an early application of large dose of ribavirin in treatment of HFRS can reduce the serum CK-MB levels in patients with HFRS.

Adult↗