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Biomedical subjects

R Jin

Publications and source records attributed to R Jin.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Pharmacognostical studies on the roots of Stellera chamaejasme and S. chamaejasme f. chrysantha].

Morphological and histological characters of the roots of Stellera chamaejasme L. and S. chamaejasme L. f. chrysantha S. C. Huang, used as the origins of the Chinese medicine Langdu, were described and illustrated with line drawings. TLC analyses of the above two drugs were also undertaken. These studies provide referencial informations for the quality control, development and identification of these two drugs.

Chromatography, Thin Layer↗
PubMed2000

[Pharmacognostical studies on the roots of Euphorbia fischeriana].

Morphological and histological characters of the roots of Euphorbia fischeriana Steud., used as one of the origins of traditional Chinese medicine Langdu, were described and illustrated with line drawings. TLC analysis of the above drug was also undertaken. These studies provide referencial informations for clinics, quality control, development and identification of this crude drug.

Chromatography, Thin Layer↗
PubMed1999

Frequency of the fragile X syndrome in Chinese mentally retarded populations is similar to that in Caucasians.

Fragile X syndrome is recognized as the most common inherited cause of mental retardation in western countries. The prevalence of the fragile X syndrome in Asian populations is uncertain. We report a multi-institutional collaborative study of molecular screening for the fragile X syndrome from 1,127 Chinese mentally retarded (MR) individuals. We found that 2.8% of the Chinese MR population screened by DNA analysis had the fragile X full mutation. Our screening indicated that the fragile X syndrome prevalence was very close to that of Caucasian subjects. In addition, we found that 62.5% of fragile X chromosomes had a single haplotype for DXS548-FRAXAC1 (21-18 repeats) which was present in only 9.7% of controls. This unique distribution of microsatellite markers flanking the FMR1 CGG repeats suggests that the fragile X syndrome in Chinese populations, as in the Caucasian, may also be derived from founder chromosomes.

Alleles↗
PubMed1999

Shared and unique determinants of the erythropoietin (EPO) receptor are important for binding EPO and EPO mimetic peptide.

We have shown previously that Phe93 in the extracellular domain of the erythropoietin (EPO) receptor (EPOR) is crucial for binding EPO. Substitution of Phe93 with alanine resulted in a dramatic decrease in EPO binding to the Escherichia coli-expressed extracellular domain of the EPOR (EPO-binding protein or EBP) and no detectable binding to full-length mutant receptor expressed in COS cells. Remarkably, Phe93 forms extensive contacts with a peptide ligand in the crystal structure of the EBP bound to an EPO-mimetic peptide (EMP1), suggesting that Phe93 is also important for EMP1 binding. We used alanine substitution of EBP residues that contact EMP1 in the crystal structure to investigate the function of these residues in both EMP1 and EPO binding. The three largest hydrophobic contacts at Phe93, Met150, and Phe205 and a hydrogen bonding interaction at Thr151 were examined. Our results indicate that Phe93 and Phe205 are important for both EPO and EMP1 binding, Met150 is not important for EPO binding but is critical for EMP1 binding, and Thr151 is not important for binding either ligand. Thus, Phe93 and Phe205 are important binding determinants for both EPO and EMP1, even though these ligands share no sequence or structural homology, suggesting that these residues may represent a minimum epitope on the EPOR for productive ligand binding.

Circular Dichroism↗
PubMed1999

Ingested interferon alpha induces Mx mRNA.

We have demonstrated that ingested murine interferon alpha (IFN-alpha) suppressed clinical relapse in chronic relapsing experimental autoimmune encephalomyelitis (CR-EAE), decreased inflammation and suppressed the adoptive transfer of EAE, and is a biological response modifier in patients with multiple sclerosis. We examined the relative levels of the Mx mRNA signal using semiquantitative reverse transcription-polymerase chain reaction analysis on splenocytes from mice and peripheral blood mononuclear cells from man after IFN-alpha ingestion. Both mice and man demonstrated inducible levels of Mx mRNA after ingesting IFN-alpha. Murine spleen T cells and CD8(+)T cells also demonstrated upregulation of Mx mRNA. Murine whole splenocytes demonstrated upregulation of Mx mRNA after IFN-alpha ingestion of 10 and 100 U, but not after 0, 1000, 5000 U. Ingested IFN-alpha acts via established pathways of type 1 IFN signalling.

Administration, Oral↗
PubMed1999

A rapid screening and diagnosis on fragile X syndrome by PCR.

Polymerase chain reaction (PCR) technique combined with direct detection by silver staining on denaturing DNA sequencing gel was used to analyze the (CGG)n repeats within the FMR1 gene on 169 suspected patients with mental retardation and 33 kindreds of 6 fragile X families. The results showed that: (1) No PCR products were detected in 3 males in the suspected group. (2) In the fragile X family studies, the 5 male probands failed to show any PCR products. (3) Diplex PCR with the primers flanking the FRAXE locus was used to serve as an internal control for the 8 above-mentioned males and only normal products of the FRAXE locus were detected, indicating that the possibility of false negative results of the FRAXA locus could be eliminated. These findings suggested that analysis of (CGG)n repeat within the FMR1 gene by PCR technique could efficiently detect premutation carriers and that negative PCR products in mentally retarded males might highly imply the diagnosis of fragile X syndrome after the false negative results have been excluded by diplex PCR. This PCR assay is suitable for the screening and diagnosis of fragile X syndrome in a large number of populations due to its rapidity, simplicity, stability and reliability.

Alleles↗
PubMed1999

The organizational context of non-lethal workplace violence: its interpersonal, temporal, and spatial correlates.

This article examines 993 violent incidents involving faculty, students, and staff that occurred at a highly ranked teaching and research university and its affiliated medical center. Violent incidents were included in the sample if they involved faculty, students, or staff, regardless of their specific location or context (i.e., whether they occurred on campus and/or off-campus and whether they occurred within the context of work or some other activity). The theoretical goal of the project was to compare work-related incidents with non-work-related incidents of interpersonal violence occurring in a single, multifunctioning, and professionally hierarchical organization. Data were collected over a 7-year period from three police departments (city, county, and university), university records, and criminal history records obtained from the state police. The coding protocol was developed to capture crime-scene information pertinent to each of the incidents. This included information about the victim, the perpetrator, the relationship between the victim and perpetrator, and the violent incident. The data were examined using nonparametric statistics and logistic regression to model predictive differences between the workplace and non-workplace incidents. The results suggest that the workplace incidents of violence differ from the non-workplace incidents according to their time, victim age, degree of victim injury, and whether the workplace is a medical location. The authors conclude that these differences are better explained by the movement of people in and out of the workplace who bring societal violence with them, rather than by a category or type of workplace violence.

Adult↗
PubMed1999

The effect of electroacupuncture on auditory P300 potential in mongolism cases.

In treating children with mongolism (Down's syndrome) with electroacupuncture, the latent period of P3 is shortened, which shows that the cerebral reaction to external stimulus in classification, encoding and recognition is accelerated. Along with the elevated P3 amplitude, the cerebrum is more capable of processing the external information, showing improvement of the mental state.

Acupuncture Therapy↗
PubMed1999

[Studies on pharmacological junctions of hairy root of Astragalus membranaceus].

OBJECTIVE: To investigate the effect of hairy root of Astragalus membranaceus(HRA). METHOD: HRA were given 10 g/kg per day for 50 days to aged mice treated with D-galactose, and the effect on memory and antioxidant functions were estimated. After administration of HRA 10 g/kg for four days, anti-ischemia-reperfusion kidney model of rat was prepared. The kidney function, activity of superoxide dismutase (SOD) and content of malondialdehyde(MDA) in kidney were examined. Mice with immunosuppression induced by cyclophosphamide were given orally HRA 10 g/kg for 12 days. The activity of natural killer (NK) cells was measured. RESULT: HRA improved the memory, raised SOD activity in brain and liver, decreased the MDA content in the liver of aged mice, reduced the MDA content in ischemia-reperfusion kidney, decreased the creatinine level in blood of rats, and promoted the activity of NK cells in immunosuppressed mice. CONCLUSION: Similar to the natural A. membranaceus, HRA has senility-preventing, antioxidizing and immunomodulating functions.

Aging↗
PubMed1999

[HPLC determination of uracil xanthine, hypoxanthine and uridine in species of animal drugs].

OBJECTIVE: To make further studies on the water-soluble components in animal drugs by determining the contents of uracil, xanthine, hypoxanthine and uridine from ten species of animal drugs. METHOD: The determination was affected by RP-HPLC, using Shim-pack CLC-ODS column(150 mm x 6 mm), 0.05 mol/L dibasic ammonium phosphate solution as mobile phase, flow rate 0.8 ml/min and detection at 254 nm. RESULTS: This method is accurate, rapid and reproducible. Analytical data for Hirudo nipponia, Eupolyphaga sinensis, Scolopendra subspinipes mutilans, Buthus martensii, Bombyx mori, Mylabris cicorri, Aspongopus chinensis, Lytta caraganae, Tabanus bivittatus and Huechys sanguinea are given. CONCLUSION: There are marked discrepancies in the contents of the four components as shown on the chromatograms, a point that may be helpful in identifying the above-cited ten species of animal drugs.

Animals↗
PubMed1999

[Studies of Echinopsis multiplex on antineoplastic effects].

Fresh Echinopsis multiplex decoction(p.o. 30 g/kg and 60 g/kg) could inhibit the growth of solid tumour S180 and Lewis pulmonary carcinoma, prolong the survival date of the mice with the tumours. In vitro, the serum of animal, which took the herb, significantly suppressed the proliferation of EAC tumour cells and inhibited the YAC-1 tumour cell DNA synthesis when compared with the serum of normal animal. The decoction did not reduce the WBC, but increased the number of PFC of spleen cells at the effective dose in mice with tumour, indicating that it did not impair the immune system, but enhance the immune function.

Animals↗
PubMed1999

[The comparison of contents of uracil, xanthine and hypoxanthine in five species of leech].

Three constituents(uracil, xanthine, hypoxanthine) were isolated from five species of leech and determined by reversed phase HPLC. The column employed was Shim-pack CLC-ODS C18(150 mm x 6 mm). The mobile phase was 0.05 mol/l ammonium phophate dibasic solution(pH = 8.4). The flow rate was 0.8 ml/min and detection was effected at 254 nm. This method is accurate, rapid and reproducible. Analytical data for five species and Whitmania pigra samples from different places were given.

Animals↗
PubMed1999

[Pharmacognostical studies on the roots of Euphorbia prolifera].

Morphological and histological characters of the roots of Euphorbia prolifera Buch.-Han., a traditional Chinese medicine, were described and illustrated with line drawings. TLC analysis of the above drug was also undertaken. These studies provide referencial informations for clinics, quality control, development and identification of this crude drug.

Chromatography, Thin Layer↗
PubMed1998

Role of human CYP4F2 in hepatic catabolism of the proinflammatory agent leukotriene B4.

Leukotriene B4 (LTB4), an arachidonic acid derivative, is a potent proinflammatory agent whose actions are terminated by catabolism via a microsomal omega-hydroxylation pathway. Although the liver serves as the principal site for LTB4 clearance from the systemic circulation, the attributes of hepatic LTB4 metabolism are ill defined in humans. Thus, we examined metabolism of LTB4 to its omega-hydroxylated metabolite 20-hydroxyleukotriene B4 (20-OH LTB4) by human liver microsomes and also purified the hepatic P450 enzyme underlying this reaction. Liver microsomes from 10 different subjects converted LTB4 to 20-OH LTB4 at similar rates (1.06 +/- 0.3 nmol/min/nmol P450; 0.25 +/- 0.1 nmol/min/mg protein). Analysis of the microsomal LTB4 20-hydroxylation reaction revealed kinetic parameters (apparent Km of 74.8 microM with a VMAX of 2.42 nmol/min/nmol P450) consistent with catalysis by a single P450 enzyme. Conventional chromatography combined with immunochemical screening with rat CYP4A1 antibodies was then used to isolate a P450 enzyme from human liver microsomes with a molecular weight of 57,000 and an NH2-terminal amino acid sequence 94% homologous (12Trp --> 12Gly) over the first 17 residues with the human CYP4F2 cDNA-derived sequence. Upon reconstitution with P450 reductase and phospholipid, CYP4F2 converted LTB4 to 20-OH LTB4 at a turnover rate of 392 pmol/min/nmol P450, whereas the other human liver P450s tested, including CYP4A11, exhibited neglible LTB4 omega-hydroxylase activity. Polyclonal antibodies to CYP4F2 were found to markedly inhibit (91.9 +/- 5%; n = 5) LTB4 20-hydroxylation by human liver microsomes. Microsomal 20-OH LTB4 formation was also inhibited 30% by arachidonic acid, a known CYP4F2 substrate, and 50% by prostaglandin A1 but was unaffected by lauric acid, palmitic acid, and PGF2alpha. Finally, a strong correlation (r = 0.86; P < 0.002; n = 10) was observed between CYP4F2 content and LTB4 20-hydroxylase activity in the human liver samples. Our results indicate that CYP4F2 is the principle LTB4 omega-hydroxylating enzyme expressed in human liver and, as such, may play an important role in regulating circulating as well as hepatic levels of this powerful proinflammatory eicosanoid.

Amino Acid Sequence↗
PubMed1998

Probing the ligand binding domain of the GluR2 receptor by proteolysis and deletion mutagenesis defines domain boundaries and yields a crystallizable construct.

Ionotropic glutamate receptors constitute an important family of ligand-gated ion channels for which there is little biochemical or structural data. Here we probe the domain structure and boundaries of the ligand binding domain of the AMPA-sensitive GluR2 receptor by limited proteolysis and deletion mutagenesis. To identify the proteolytic fragments, Maldi mass spectrometry and N-terminal amino acid sequencing were employed. Trypsin digestion of HS1S2 (Chen GQ, Gouaux E. 1997. Proc Natl Acad Sci USA 94:13431-13436) in the presence and absence of glutamate showed that the ligand stabilized the S1 and S2 fragments against complete digestion. Using limited proteolysis and multiple sequence alignments of glutamate receptors as guides, nine constructs were made, folded, and screened for ligand binding activity. From this screen, the S1S21 construct proved to be trypsin- and chymotrypsin-resistant, stable to storage at 4 degrees C, and amenable to three-dimensional crystal formation. The HS1S21 variant was readily prepared on a large scale, the His tag was easily removed by trypsin, and crystals were produced that diffracted to beyond 1.5 A resolution. These experiments, for the first time, pave the way to economical overproduction of the ligand binding domains of glutamate receptors and more accurately map the boundaries of the ligand binding domain.

Amino Acid Sequence↗
PubMed1998

Anticarcinogenic effects of shikaron, a preparation of eight Chinese herbs in mice treated with a carcinogen, N-butyl-N'-butanolnitrosoamine.

We studied the effects of Shikaron, which is composed of 8 Chinese herb extracts, on carcinogenesis and the cytotoxic activity and cytokine production of lymphocytes in mice treated with a carcinogen, N-butyl-N'-butanolnitrosoamine (BBN). We found a significantly lower incidence of urinary bladder carcinoma in mice treated with BBN plus Shikaron 200 mg/kg/day (5 of 20 mice, 25%), than in mice treated with BBN alone (16 of 20 mice, 80%). Shikaron protected the cytotoxic activity of lymphocytes against YAC-1 cells from suppression by BBN. Cytotoxic activity against P-815 cells significantly increased in mice treated with BBN plus Shikaron, as compared with normal mice and BBN-treated mice. Shikaron also protected production of interleukin-2 and interferon-gamma by lymphocytes from suppression by BBN. These findings strongly suggest that Shikaron exerted an anticarcinogenic effect in carcinogen-treated mice through activation of NK and LAK cells and cytokine production by T lymphocytes.

Animals↗
PubMed1998

[Effects of hairy root huangqi on hemopoietic function].

The effects of hairy root Huangqi on hemopoietic system were studied in this paper. The oral administration of 5-20 g/kg hairy root Huangqi per day for 5-12 days could increase the count of RBC and reticulocytes in mice with hemorrhagic anemia, raise the hemoglobin, RBC and hematocrit in mice with hemolytic anemia, enhance the number of WBC and nucleared cells in bone marrow of mice treated with cyclophosphamidum or x-rays. The experiments showed that hairy root Huangqi promoted the hemopoietic function. The effects were similer to those of natural Huangqi.

Anemia, Hemolytic↗