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Biomedical subjects

S Feng

Publications and source records attributed to S Feng.

At least 55 records · Page 3Linked to original sources
PubMed2001

Identification and quantitation of 11-nor-delta9-tetrahydrocannabivarin-9-carboxylic acid, a major metabolite of delta9-tetrahydrocannabivarin.

After incubation of delta9-tetrahydrocannabivarin with human hepatocytes, a major metabolic product was detected by gas chromatography-mass spectrometry that showed identical retention time and mass spectrum to the synthetic 11-nor-delta9-tetrahydrocannabivarin-9-carboxylic acid (11-nor-delta9-THCV-9-COOH). Analysis of human urine specimens from marijuana users and plasma samples from Marinol users showed that 11-nor-delta9-THCV-9-COOH was only present in urine specimens of marijuana users. These results supported the conclusion that identification of 11-nor-delta9-THCV-9-COOH in a donor's urine specimen indicates the use or ingestion of cannabis-related product(s) and would not explain the sole use of Marinol.

Chromatography, High Pressure Liquid↗
PubMed2001

Delta9-tetrahydrocannabivarin as a marker for the ingestion of marijuana versus Marinol: results of a clinical study.

Delta9-tetrahydrocannabinol (THC), the main psychologically active ingredient of the cannabis plant (marijuana), has been prepared synthetically and used as the bulk active ingredient of Marinol, which was approved by the FDA for the control of nausea and vomiting in cancer patients receiving chemotherapy and as an appetite stimulant for AIDS patients. Because the natural and the synthetic THC are identical in all respects, it is impossible to determine the source of the urinary metabolite of THC, 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH), in a urine specimen provided in a drug-testing program. Over the last few years there has been a need to determine whether a marijuana positive drug test is the result of the ingestion of marijuana (or a related product) or whether it results from the sole use of Marinol. We have previously proposed the use of delta9-tetrahydrocannabivarin (THCV, the C3 homologue of THC) as a marker for the ingestion of marijuana (or a related product) because THCV is a natural component of most cannabis products along with THC and does not exist in Marinol. We have also reported that THCV is metabolized by human hepatocytes to 11-nor-delta9-tetrahydrocannabivarin-9-carboxylic acid (THCV-COOH); therefore, the presence of the latter in a urine specimen would indicate that the donor must have used marijuana or a related product (with or without Marinol). In this study, we provide clinical data showing that THCV-COOH is detected in urine specimens collected from human subjects only after the ingestion of marijuana and not after the ingestion of Marinol (whether the latter is ingested orally or by smoking). Four subjects (male and female) participated in the study in a three-session, within-subject, crossover design. The sessions were conducted at one-week intervals. Each subject received, in separate sessions and in randomized order, an oral dose of Marinol (15 mg), a smoked dose of THC (16.88 mg) in a placebo marijuana cigarette, or a smoked dose of marijuana (2.11% THC and 0.12% THCV). Urine samples were collected and vital signs were monitored every 2 h for a 6-h period following drug administration. Subjects were then transported home, were given sample collection containers and logbooks, and were instructed to record at home the volume and time of every urine collection for 24 h, and once a day for the remainder of a week (6 days). Subjects were also instructed to freeze the urine samples until the next session. All urine samples were analyzed by GC-MS for THC-COOH and THCV-COOH using solid-phase extraction and derivatization procedure on RapidTrace and TBDMS as the derivative. The method had a limit of detection of 1.0 ng/mL and 1.0 ng/mL for THCV-COOH and THC-COOH, respectively.

Administration, Oral↗
PubMed2001

Hydrolysis of conjugated metabolites of buprenorphine. I. The quantitative enzymatic hydrolysis of buprenorphine-3-beta-D-glucuronide in human urine.

Buprenorphine, which is a powerful analgesic, a substitution drug for opioids widely used in Europe, and a promising new drug currently undergoing clinical trials in the treatment of opioid dependence in the U.S., is excreted in human urine mainly as glucuronide conjugates. In gas chromatographic-mass spectrometric analysis, the urine specimens must be first hydrolyzed to release buprenorphine from its glucuronide conjugates. In order to evaluate the existing hydrolysis methods and to find the optimal hydrolysis conditions, buprenorphine-3-beta-D-glucuronide (B3G) was synthesized. Urine fortified with synthetic B3G was hydrolyzed using acid, base, and beta-glucuronidases from different source species, including Helix pomatia, Escherichia coli, and Patella vulgata. Glusulase, a preparation containing both beta-glucuronidase (H. pomatia) and sulfatase, was also tested. Whereas both acidic and basic hydrolysis were ineffective, quantitative hydrolysis could be achieved by using beta-glucuronidases under appropriate conditions. However, we found that there was a marked difference in the reactivity of these enzymes (E. coli > H. pomatia >> P. vulgata). The optimal incubation conditions for enzymatic hydrolysis of B3G were 2 h at 37 degrees C for E coli and 4 h at 60 degrees C or 16 h at 37 degrees C for H. pomatia. Using 1000 Fishman units of either of these two enzymes, effective hydrolysis could be achieved even when the B3G concentration was as high as 2000 ng/mL. Glusulase was equally effective toward B3G if the fortified urine samples were incubated with 25 microL of this enzyme for 1 h at 60 degrees C.

Animals↗
PubMed2001

MR arthrography of the glenohumeral joint: a tailored approach.

OBJECTIVE: The purpose of this study was to anatomically confirm that anterior shoulder injection could result in penetration of the anterior stabilizing structures of the glenohumeral joint and to advocate the use of a tailored approach to MR arthrography based on presenting symptoms. CONCLUSION: A tailored approach to MR arthrography may be a useful way to isolate expected pathology in the shoulder and limit confounding findings related to the performance of the procedure.

Aged↗
PubMed2001

[Complex segregation analysis of systemic lupus erythematosus].

OBJECTIVE: To explore the genetic model of systemic lupus erythematosus(SLE). METHODS: Complex segregation analysis was performed by using statistical analysis for genetic epidemiology-REGTL(SAGE-REGTL). The genetic model and gene frequency were estimated. 300 pedigrees with SLE were collected from 300 patients as probands. RESULTS: The complex segregation analysis found the genetic model of SLE to be additive,the gene frequency 0.336. The authors believe the possibility of some different modes coexisting under different circumstances. The genetic effect on young man is stronger than that on old one. CONCLUSION: This study suggests that the genetic mode of SLE could be the major gene trait, and additive mode is the best fitted one.

Adolescent↗
PubMed2001

Atrioventricular block complicating inferior acute myocardial infarction treated with thrombolytic therapy.

OBJECTIVE: To investigate the influence and mechanism of incidence of atrioventricular block (AVB) treated with thrombolytic therapy in acute inferior myocardial infarction (AIMI). METHODS: A total of 46 patients with AIMI were divided into the thrombolytic group (n = 23) and the non-thrombolytic group (n = 23). Intravenous or intracoronary urokinase was given to the former group. We observed the advancing courses of AVB, and further assessed the relationship between occurrence of AVB and stenosis of infarct-related artery (IRA) with coronary angiography. RESULTS: Two cases died of III degree AVB in the non-thrombolytic group, but none was found in the thrombolytic group. The occurrence rate of AVB was similar in both groups; but that of III degree AVB was much lower in the thrombolytic group (4 cases) than that in the non-thrombolytic group (11 cases, P < 0.05), and the duration of AVB decreased from 201 +/- 113 hours to 102 +/- 60 hours after thrombolytic therapy (P < 0.01), which was mainly due to the decrease of AVB in the vanishing interval, but not in the developing interval. The coronary angiography demonstrated that there were an increasing reperfusion flow and a decreasing coronary stenosis of the infarct-related artery after thrombolytic therapy. CONCLUSION: Thrombolytic therapy can reduce the incidence of severe AVB, shorten its duration and decrease the mortality by increasing the coronary reperfusion flow in the patients with AIMI.

Adult↗
PubMed2001

[Establishment of trans-inactivation system for haloalkane dehalogenase gene in Arabidopsis thaliana].

With haloalkane dehalogenase gene (dhlA) of Xanthobacter autothophicus as a negative selection marker, a novel trans-inactivation system for transgenes in plants was developed. After the Arabidopsis plants were transformed with dhlA, one plant was shown dhlA post-transcriptional silencing by nuclear run-off transcriptional analysis. The Arabidopsis plants containing silencing locus were crossed to those efficiently expressed dhlA, referred as a homologous transgenic locus, and 96% of F1 plants became the homologous dhlA inactivated in trans. When the F1 plants were selfed, and the silencing locus and the homologous locus were separated in some progenies, 42 of the 200 progenies exhibited DhlA activity, and 158 no DhlA activity, and the proportion of the DhlA-expressing plants to the dhlA-silencing ones was 3.76 to 1, which suggested that the silencing locus inactivated in trans the homologous transgenic locus as a Mendelian dominant factor.

Arabidopsis↗
PubMed2001

[Modification of transnasal medial canthopexy].

OBJECTIVE: To study the curative effect of transnasal medial canthopexy. METHODS: By a coronal or medial canthal incision, we applied transnasal medial canthopexy to repair medial canthal detachment. A total of 78 patients received the operation. RESULTS: Of them, 64 patients obtained satisfactory postoperative appearance with one operation; 6 patients obtained satisfactory results with two operations. The operation was unsuccessful in 8 patients. CONCLUSION: This method is one of the ideal methods of repairing medial canthal detachment, however its indications should be observed.

Adolescent↗
PubMed2001

Evaluation of diagnostic methods for Helicobacter bilis infection in laboratory mice.

Disease-susceptible (C3H) and -resistant (B6) immunocompetent and immunodeficient (C3H-scid and B6-rag1) mice were examined up to 10 weeks after inoculation with Helicobacter bilis (a prototype species of proven virulence). Infection was monitored weekly by use of fecal culture, polymerase chain reaction (PCR) nucleic acid amplification, membrane extract enzyme-linked immunosorbent assay (ELISA), and histologic examination. All mice became infected by three to five weeks after inoculation, on the basis of results of culture and PCR analysis of feces. The PCR analysis was more sensitive than culture at determining infection status, particularly during early infection. None of the mice had evidence of disease by week 10. Immunoglobulin G seroconversion was detectable in C3H mice by week eight and in B6 mice by week nine. Results indicated that culture and PCR analysis are more sensitive than is membrane extract ELISA serologic testing for detecting early infection in individual mice, regardless of genotype or immune status. Results underscore the need for improved seroassays for this important group of murine pathogens.

Adoptive Transfer↗
PubMed2001

[Expression of leukemia inhibitory factor in the decidua of normal early pregnancy, threatened abortion and inevitable abortion].

OBJECTIVE: To investigate the expression of leukemia inhibitory factor (LIF) in the decidua of normal early pregnancy, threatened abortion and inevitable abortion. METHOD: We examined LIF gene expression in the above-mentioned decidua by a quantitative reverse transcription-polymerase chain reaction (RT-PCR) method, and also examined the serum pregesterone, human chorionic gonadotrapin (hCG) by radioimmunoassay in all cases. RESULTS: (1) Serum levels of pregesterone and hCG are: (91.5 +/- 27.2) nmol/L, (69.9 +/- 14.9) kU/L in normal early pregnancy; (88.4 +/- 24.7) nmol/L, (57.6 +/- 11.2) kU/L in threatened abortion respectively. There was no difference in the levels of pregesterone and hCG between the two groups (P > 0.05). While serum pregesterone, hCG levels in inevitable group were (33.1 +/- 19.6) nmol/L, (10.3 +/- 3.2) kU/L respectively. Compared with normal early pregnancy and threatened abortion group, the levels of serum pregesterone and hCG reduced significantly (P < 0.05). (2) The expression of LIF in three groups: There was no statistically significant difference in the levels of LIF expression between the normal early pregnancy group (2.10 +/- 0.32) and threatened abortion (1.92 +/- 0.20) groups, while the levels of LIF expression in inevitable abortion group (0.7 +/- 0.06) was lower than those in normal early pregnancy group and threatened abortion group (P < 0.05, respectively). CONCLUSION: The reduction of LIFmRNA expression in the decidua of early pregnancy may decrease the serum pregesterone and hCG levels and cause inevitable abortion.

Abortion, Spontaneous↗
PubMed2001

Studies on the development of DNA vaccine against Cysticercus cellulosae infection and its efficacy.

DNA vaccine against Cysticercus cellulosae infection was developed and its efficacy was tested. A pair of primers specific to antigen B gene of C. cellulosae was designed which amplified the gene successfully with RT-PCR. The gene was ligated to PV93 vector, and the recombinant of antigen B gene and PV93 was transformed to JM83 cells. The transformed JM83 cells were cultured in a large scale and the plasmid purified. Based on the recombinant plasmid. a DNA vaccine was developed and used to vaccinate two groups of experimental pigs. In each group, there was a routine vaccine, an enhanced vaccine and a control group. Groups 1 and 2 were challenged at 4 months and at 14 days post vaccination respectively with eggs of Taenia solium. The antibody response was also tested with ELISA. The results suggested that all animals vaccinated AgB gene DNA vaccine, no matter by routine or enhanced vaccine, their antibodies reached maximum peak 23 days post vaccination and decreased gradually. When the animals were challenged 4 months after vaccination, they had strong immunity and the parasites decrease rates were 91.2% and 93.1% respectively. When pigs vaccinated with AgB gene DNA vaccine were challenged 14 days post vaccination with 18,000 eggs/pig. The animals showed strong immunity and the parasite decrease rates were 99.5% and 84.9% respectively. However at that time, the antibodies did not reach the peak. While in the control group, the number of C. cellulosae was as many as 2,500. It was concluded that the pigs vaccinated with DNA vaccine had strong immunity against infection of eggs of T. solium.

Animals↗
PubMed2001

Approach to the management of allograft recipients following the detection of hepatitis B virus in the prospective organ donor.

Hepatitis B virus (HBV) is a highly infectious blood-borne pathogen that can be transmitted by a solid organ allograft and result in substantial morbidity and mortality. Recent advances in the management of HBV infection prompt a reappraisal of the approach to the management of allograft recipients from cadaver donors previously exposed to HBV, because of the on-going shortage of organ donors. This report reviews current knowledge regarding the risk of HBV transmission by an organ from cadaver donors testing positive for markers of HBV infection and makes recommendations for the evaluation, treatment, and surveillance of the allograft recipients.

Hepatitis B↗
PubMed2001

[Studies on the genotoxic effects of acrylonitrile].

The effect of acrylonitrile (AN) on the reproduction was investigated in 341 male and 365 female exposed workers, 384 male and 438 female unexposed controls by questionnaires on the process of childbearing and the outcome of child birth. The results showed that AN caused menstrual disorder and dysgenesis in exposed female workers and the wife of exposed male workers. It is concluded that AN is harmful to the reproduction of exposed male and female workers.

Acrylonitrile↗
PubMed2000

A dendritic cell line genetically modified to express CTLA4-IG as a means to prolong islet allograft survival.

BACKGROUND: Dendritic cells are potent antigen-presenting cells that bind allogeneic T cells. They are thus candidates for targeting immunoregulatory molecules to the alloreactive T cell compartment and suppressing the alloimmune response. METHOD: A dendritic cell line derived from the BALB/c mouse (H2d) was genetically modified to express the immunoregulatory molecule CTLA4-Ig. The ability of these dendritic cell transfectants to downregulate the alloimmune response was tested in an islet transplant model. Allogeneic C57Bl/6 (H2b) mice were rendered diabetic with streptozocin, and they received BALB/c islet (H2d) transplants. Mice were administered 25 million untransfected or CTLA4-Ig-transfected D2SC/1 cells i.v. on the day of islet transplantation and 6 days later[fnc]. RESULT: Mice treated with CTLA4-Ig-transfected D2SC/1 cells demonstrated prolonged allograft survival (mean = 20 days, median = 17 days, SD = 9.39) compared with mice treated with untransfected D2SC/1 cells (mean = 12 days, median = 11 days, SD=2.74) or untreated control mice (mean = 11 days, median = 11 days SD = 1.41). Third party allograft survival was not prolonged in mice receiving similar treatment. CONCLUSIONS: These results demonstrate that a genetically modified dendritic cell line can suppress the alloimmune response and prolong islet allograft survival in an allospecific manner. The findings also suggest that genetically modified dendritic cells may be useful in targeting alloreactive T cells and prolonging allograft survival.

Abatacept↗
PubMed2000

Cytoplasmic domains of GpIbalpha and GpIbbeta regulate 14-3-3zeta binding to GpIb/IX/V.

Shear stress causes the platelet glycoprotein (Gp) Ib/IX/V to bind to von Willebrand factor, resulting in platelet adhesion. GpIb/IX/V also functions to stimulate transmembranous signaling, leading to platelet activation and the expression of a ligand-receptive GpIIb-IIIa complex. The highly conserved cytoplasmic domain of GpIbalpha binds directly to a dimeric 14-3-3 adapter protein zeta isoform. To explore structural determinants of GpIb/IX/V binding to 14-3-3zeta, the authors examined 14-3-3zeta interactions with GpIbalpha and GpIbbeta in heterologous cells and platelets. Truncations of GpIbalpha at amino acid 542 or 594, or deletions of residues 542 through 590, inhibited binding of 14-3-3zeta. Deletion of GpIbalpha from Trp(570) to Ser(590) eliminated 14-3-3zeta binding, and deletion of the sequence from Arg(542)-Trp(570) enhanced binding of 14-3-3zeta to GpIbalpha. All GpIbalpha mutations that eliminated GpIbalpha binding to the GST-14-3-3zeta fusion protein also eliminated GpIbbeta binding to the fusion protein. Forskolin treatment of Chinese hamster ovary cells expressing wild-type GpIbalpha/beta/IX resulted in the phosphorylation of GpIbbeta associated with enhanced binding of GpIbbeta to GST-14-3-3zeta fusion protein and increased 14-3-3zeta coimmunoprecipitated with GpIbalpha. When intact human platelets aggregated in response to 90 dynes/cm(2) shear stress, 14-3-3zeta disassociated from GpIbalpha. Prostacyclin treatment of platelets inhibited shear stress-induced aggregation and the release of 14-3-3zeta from GpIbalpha. These data demonstrate that amino acid residues in the cytoskeletal interaction domains of GpIbalpha regulate 14-3-3zeta binding to GpIbalpha/beta/IX, and suggest that protein kinase A-dependent phosphorylation of GpIbbeta enhances 14-3-3zeta binding to the GpIb/IX/V complex in human platelets. (Blood. 2000;95:551-557)

14-3-3 Proteins↗