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Biomedical subjects

P Ren

Publications and source records attributed to P Ren.

At least 37 records · Page 2Linked to original sources
PubMed1997

Expression of growth factors in chicken growth plate with special reference to tibial dyschondroplasia.

Immunoreactive growth factors were identified in chick embryonic cartilage and bone, and in the growth plate of normal tibiotarsi and tibiotarsi affected with tibial dyschondroplasia (TD). A specific pattern of temporal and spatial expression was observed for each growth factor. Transforming growth factor beta and alpha (TGF beta and TGF alpha) and epidermal growth factor (EGF) were briefly expressed in chondrocytes of early chick embryos. Immunolabelling for TGF beta then gradually shifted into cartilaginous matrix and was not observed in cytoplasm of hypertrophic chondrocytes until the late embryonic and post-hatch stages. The distribution and intensity of TGF beta labelling was the same in chondrocytes of the TD and normal growth plate. Insulin-like growth factor I (IGF-I) labelling persisted from the early embryonic stage to the end of the mid-stage and then disappeared from chondrocytes. IGF-I appeared again in chondrocytes 1-2 days before hatching. After hatching, the labelling intensified in prehypertrophic and hypertrophic chondrocytes. TD lesions displayed IGF-I in the distal region, mainly in chondrocytes around small blood vessels. EGF reappeared in proliferative and hypertrophic chondrocytes of the mid-embryonic stage. By day 18 after hatching, EGF was present mainly in prehypertrophic and hypertrophic chondrocytes. EGF was demonstrated only in distal proliferative and early prehypertrophic chondrocytes of the dyschondroplastic growth plate. TGF alpha was identified in hypertrophic chondrocytes adjacent to the periosteum and in the distal tip of the mid-embryonic growth plate. With progressing ossification, TGF alpha labeling intensified in the embryonic hypertrophic chondrocytes. In the TD growth plate at day 18 after hatching, TGF alpha expression was limited to 1-3 concentric layers of chondrocytes surrounding blood vessels.

Animals↗
PubMed1997

[Detection of Chlamydia trachomatis and Ureaplasma urealyticum from aborted tissues by polymerase chain reaction technique].

OBJECTIVE: To study the prevalence of Chlamydia trachomatis (CT) and Ureaplasma urealyticum (UU) infection in spontaneous abortion patients. METHODS: CT and UU in aborted tissues were determined by polymerase chain reaction (PCR) technique in 45 spontaneous abortion patients (abortion group) and 25 artificial abortion cases (control group). RESULTS: The detective rate of CT and UU was 42.2% and 33.3% respectively in the abortion group. As compared with the control group significant difference (P < 0.01, P < 0.025) was shown. The detection rate of mixed CT and UU is 8.9%. CONCLUSION: CT and UU are important infection factors which may cause spontaneous abortion. PCR examination of the aborted tissue can submit an accurate, rapid microorganic diagnosis of CT and (or) UU infection.

Abortion, Spontaneous↗
PubMed1997

[Effect of sijunzi decoction on motilin and pharmacokinetic characteristics of tetramethylpyrazine in rat model of spleen deficiency syndrome].

OBJECTIVE: To explore relationship between the essence of Spleen Deficiency Syndrome (SDS) and pharmacokinetic characteristics (PK). METHODS: The level of motilin in serum and intestine, and PK of tetramethylpyrazine phosphate (TMPP) in rat model of SDS were observed simultaneously and treated with Sijunzi decoction (SJZD) for confirmation. RESULTS: The atrioventricular model of TMPP in SDS, normal and SJZD treated rats all belonged to the open double ventricular type; there were insignificant differences between normal and SJZD treated rats in motilin level and PK of TMPP, but the differences of these parameters between normal and SDS model rats were significantly (P < 0.01). The SDS state could markedly affect the absorption, distribution, metabolism and elimination of TMPP in rat; SJZD could normalize the abnormal PK of TMPP in SDS model rats. CONCLUSIONS: A supplementary scientific evidence for the hypothesis of "Pharmacokinetics of Syndrome Differentiation" is provided.

Animals↗
PubMed1996

Control of C. elegans larval development by neuronal expression of a TGF-beta homolog.

The Caenorhabditis elegans dauer larva is specialized for dispersal without growth and is formed under conditions of overcrowding and limited food. The daf-7 gene, required for transducing environmental cues that support continuous development with plentiful food, encodes a transforming growth factor-beta (TGF-beta) superfamily member. A daf-7 reporter construct is expressed in the ASI chemosensory neurons. Dauer-inducing pheromone inhibits daf-7 expression and promotes dauer formation, whereas food reactivates daf-7 expression and promotes recovery from the dauer state. When the food/pheromone ratio is high, the level of daf-7 mRNA peaks during the L1 larval stage, when commitment to non-dauer development is made.

Amino Acid Sequence↗
PubMed1996

Inhibition of gap junctional intercellular communication by barbiturates in long-term primary cultured rat hepatocytes is correlated with liver tumour promoting activity.

Rodent liver tumor formation can be promoted by certain barbiturates and this may involve their ability to inhibit hepatocyte gap junctional intercellular communication (GJIC). In order to address the mechanisms and specificity of action of barbiturates on hepatocyte gap junctions, we have compared the effects of liver tumor-promoting barbiturates (phenobarbital, sodium barbital and amobarbital: PB, SB and AB, respectively) and a non-liver tumor-promoting barbiturate (barbituric acid: BA) on primary cultured rat hepatocyte GJIC and connexin32 (Cx32) expression after short (1-24 h) and long (2-14 days) treatment. GJIC was evaluated by fluorescent dye microinjection (dye-coupling); Cx32 expression was monitored by Northern blot, Western blot and immunohistochemistry. Both parameters were maintained at high levels over 14 days by coculture of the cells with WB-F344 rat liver epithelial cells in the presence of dexamethasone. Treatment with PB (2 mM) for 1 h sharply reduced dye-coupling from approximately 90-30%, but the cells fully recovered by 24 h. No inhibition was seen with the other barbiturates over this 1-day treatment period. Longer treatments (2-14 days) with the promoters PB, SB and AB, however, gradually reduced hepatocyte dye-coupling to approximately 30-50%. The non-promoter, BA, did not affect hepatocyte GJIC. These decreases in hepatocyte dye-coupling occurred without changes in Cx32 or gap junction expression. Dye-coupling of WB-F344 cells and expression of their predominant gap junction protein, connexin43 (Cx43), were also not affected. Thus, the inhibition of GJIC was specific to liver tumor promoting barbiturates in hepatocytes, was time-dependent and was not due to altered Cx32 expression.

Animals↗
PubMed1996

Effects of tetramethylpyrazine phosphate and sodium ferulate alone or in combination on hemodynamics in anesthetized dog.

Hemodynamic actions of intravenous (iv) administration of tetramethylpyrazine phosphate (TMPP) and sodium ferulate (SF) alone or in combination were studied in anesthetized dogs. When given alone, TMPP increased left ventricular systolic pressure (LVSP), peak positive first derivative of left ventricular pressure (+LVdp/dt), coronary blood flow (CBF) and heart rate (HR) while decreasing mean aortic pressure (mAoP). SF alone did not produce any significant hemodynamic changes. When the two were administered in combination, SF antagonized dose-dependently the hemodynamic actions of TMPP. Results of this study did not support the efficacy of combined treatment of Ligusticum wallichi and Angelica root, which contain TMPP and SF respectively.

Analysis of Variance↗
PubMed1996

Regulation of rat Na+/Pi cotransporter-1 gene expression: the roles of glucose and insulin.

Cytosolic inorganic phosphate (P(i)) is important for glucose metabolism. It plays a role in homeostatic regulation of glucose by insulin and glucagon. Recently, we isolated two cDNA clones for rat Na+/P(i) cotransporter-1 (rNaPi-1) and demonstrated that they are expressed primarily in the rat liver and kidney. We now report that the expression of rNaPi-1 in these tissues is regulated by fasting and streptozotocin-induced diabetes. Using rat hepatocytes in primary culture, we also demonstrate that glucose and insulin upregulate rNaPi-1 expression, whereas glucagon and elevated intracellular adenosine 3',5'-cyclic monophosphate levels downregulate its expression. Because 2-deoxyglucose exhibits no effect on rNaPi-1 gene expression, we suggest that some metabolite accumulated during glucose metabolism may be responsible for the effects of glucose and insulin on rNaPi-1 gene expression. Our data also reveal that other known Na+/P(i) cotransporter genes, NaPi-2 and Ram-1 (a receptor for amphotropic murine retrovirus), are not regulated by insulin and glucose. It is therefore proposed that various subtypes of Na+/P(i) cotransporters are differentially regulated and that each subtype may be involved in a specific cellular function, rNaPi-1 may be responsible for Pi uptake by liver and kidney for glucose metabolism, whereas NaPi-2 may play a key role in P(i) reabsorption in the kidney.

Animals↗
PubMed1996

[Anterior chamber associated immune deviation inhibiting experimental autoimmune uveoretinitis].

OBJECTIVE: To study the inhibition of occurrence and development of experimental autoimmune uveoretinitis (EAU) by the induction of anterior chamber associated immune deviation (ACAID). METHODS: All animals (guinea pigs), except controls, were pretreated with anterior chamber injection of allogeneic retinal extract to induce ACAID, and thereafter, they received intradermal footpad immunization of the same antigen in complete Freund's adjuvant (CFA) for induction of EAU, and dead pertussis bacilli were also subcutaneously injected as a second adjuvant. The pathological changes were investigated by light and electron microscopy. RESULTS: The incidence of EAU in experimental group was 25.0%, whereas 85.7% in the positive controls. CONCLUSION: ACAID does, to a great extent, inhibit the incidence and development of EAU.

Animals↗
PubMed1995

Bacterial expression of human chorionic gonadotropin alpha subunit: studies on refolding, dimer assembly and interaction with two different beta subunits.

Human chorionic gonadotropin (hCG) is a member of a family of heterodimeric glycoprotein hormones that have a common alpha subunit but differ in their hormone-specific beta subunit. The common alpha subunit contains two asparagine (N)-linked oligosaccharides. To study the function of carbohydrates on in vitro refolding of alpha subunit and dimer assembly, we generated recombinant non-glycosylated hCG alpha subunit (rNGl-hCGalpha) from E. coli. The expression vector was constructed by inserting hCGalpha cDNA coding for the mature form in-frame into a pQE-30 vector, which contains a 6 x His sequence immediately before the 5'-end of hCGalpha cDNA for subsequent purification of rNG-hCGalpha. The rNG-hCGalpha expressed in inclusion bodies was efficiently purified by immobilized metal chelate affinity chromatography on Ni-NTA resin. SDS-PAGE, solid-phase binding assay and immunoblotting demonstrated the expression of rNG-hCG. Its alpha molecular weight on SDS-PAGE was 14.7 kDa under reducing conditions and 15 kDa for a monomer accompanied with some higher molecular weight oligomer under non-reducing conditions. Reconstitution of rNG-hCGalpha with native hCGbeta and oFSHbeta occurred in very low yield under standard conditions. However, the oxidation-reduction system cystamine (1.34 mM) and cysteamine (7.3 mM) facilitated both the refolding of rNG-hCGalpha and reconstitution of rNG-hCGalpha with native hCGbeta to regain partially correct conformation. These were revealed by conformationally sensitive antibody and receptor binding assays. Cystamine and cysteamine were more effective in the recombination of rNG-hCGalpha with oFSHbeta as indicated by a 22-36-fold decrease in the amount required to cause a 50% competitive inhibition in radioreceptor assay. They have no effect on assembly of rNG-hCGalpha with oLHbeta. Our results suggest the carbohydrate moieties confer greater conformational flexibility to the backbone of the beta subunit and the relative rigidity of the beta subunit may serve as a conformational template of the alpha subunit. The present approach has made it possible to prepare the non-glycosylated gonadotropin alpha subunit in adequate amounts for further study on their biological and topographical features in complete absence of carbohydrate.

Amino Acid Sequence↗
PubMed1995

Lymphocyte proliferation response to S antigen in patients with uveitis and optic neuritis.

PURPOSE: To evaluate the autoimmunity which may play a major role in the etiology of certain forms of uveitis and optic neuritis. METHODS: Lymphocyte proliferation response to retinal soluble antigen in vitro by incorporation 3H-thymidine with DNA was tested in 115 patients with anterior uveitis, posterior/pan-uveitis, optic neuritis, and 50 volunteers with unrelated diseases such as congenital ptosis, strabismus, or completely healthy persons as control. RESULTS: The positive rate of lymphocyte stimulation was 34% (18/53) in anterior uveitis, 41.5% (17/41) in posterior/pan-uveitis, and 57.1% (12/21) in optic neuritis. The results in the experimental groups were significantly different from those of the control group (X2 = 14.76, P < 0.05, x2 = 19.14, P < 0.005, x2 = 26.38, P < 0.005, respectively). CONCLUSION: The autoimmunity plays a role in the pathogenesis in certain forms of uveitis and optic neuritis. Such immune responses may be secondary to the exposition or release of retinal antigens by various causes, leading to activation or augmentation of meager or low-affinity S antigen specific lymphocytes which may pre-exist in the circulation and starting the pathogenic autoimmune process.

Adolescent↗
PubMed1994

Enhancement of liver cell gap junction protein expression by glucocorticoids.

Gap junctional intercellular communication (GJIC) and the expression of gap junction proteins (connexins) may be involved in growth regulation and neoplastic transformation. The mechanisms of connexin gene regulation in normal and neoplastic tissues are poorly understood. In this study, the glucocorticoids, dexamethasone and hydrocortisone, enhanced fluorescent dye-coupling in primary cultured rat hepatocytes and MH1C1 rat hepatoma cells. Other types of steroids (beta-estradiol, testosterone, aldosterone and progesterone) had no effect. Northern blot, Western blot, nuclear run-on and immunohistochemical analyses showed that glucocorticoids enhanced the expression of connexin32 in these cells in a dose- and time-dependent fashion. Connexin26 expression was also enhanced slightly by dexamethasone in hepatocytes, but not MH1C1 cells. Connexin43 expression in these cells was not affected by steroids. In WB-F344 rat liver epithelial cells, which were highly coupled and expressed high levels of connexin43 and no detectable connexin32 or connexin26, dexamethasone had no effect on coupling or connexin expression. These results indicate that dye-coupling and the expression of connexin32 and connexin26, but not connexin43, were upregulated by glucocorticoids in a cell-specific manner. These effects on GJIC and connexin expression may be involved in the induction of hepatic differentiation and inhibition of growth.

Animals↗
PubMed1994

[Pharmacokinetic characteristics of tetramethylpyrazine and study on hemorheology in rat model of spleen deficiency syndrome].

UNLABELLED: In this experiment, the essence of Spleen Deficiency Syndrome (SDS) was explored with the rat model of SDS using tetramethylpyrazine (TMP). 120 Wistar rats were divided into two groups, 60 each for control and test group, they were treated with normal saline and reserpine respectively. The hemorheological parameters were also studied in 6 each of both groups. The pharmacokinetic properties were investigated in the remaining control group and test group. RESULTS: (1) Two-compartment open model of the control group was turned into that of one-compartment in test group; (2) The SDS model significantly affected the absorption and distribution of TMP in rats. AUC was much higher and serum concentration of TMP increased significantly than that of control. Hemorheological parameters (viscosity of whole blood, fibrinogen, etc.) increased significantly (P < 0.05-0.01), it demonstrated that the SDS model was in a state of Blood Stasis. It might be one of the pharmacokinetic mechanisms of TMP in the SDS model of rats.

Animals↗
PubMed1994

[Influence of combined Salvia miltiorrhiza and Ligusticum wallichii on pharmacokinetics of tetramethylpyrazine in rats].

Influence of Salvia miltiorrhiza (SM) and/or Ligusticum wallichii (LW) on pharmacokinetics of tetramethylpyrazine (TMP) was observed in rats. The content of TMP in LW and LW-SM decoctions were 375.8 and 236.2 micrograms/ml respectively. The rat serum components after oral administration of LW were analyzed by modified HPLC. One of 3 compounds was detected, which was identified as TMP by the comparison of the parameters of 4 spectrums (UV, IR, MS and NMR) with those of TMP in literature. Pharmacokinetics of TMP in rats after the oral administration of LW and LW-SM decoction respectively showed that: (1) both of the data fitted adequately to two-compartment open model; (2) Ka, AUC and serum concentration were higher (P < 0.05-0.01) for LW decoction than that for LW-SM decoction, indicating a higher bioavailability. It demonstrated that the absorption of TMP of LW-SM decoction was slower and the bioavailability of TMP of LW-SM decoction reduced. Contents of TMP in LW and LW-SM decoction and serum concentration of TMP were determined by HPLC method.

Animals↗
PubMed1992

Combined treatment with photodynamic therapy and chemotherapy for advanced cardiac cancers.

In all, 144 patients with advanced cardiac cancers have been treated by photodynamic therapy (PDT), combined chemotherapy and chemotherapy alone from September 1982 to July 1990. A total of 5 mg kg-1 haematoporphyrin derivative (HpD) was intravenously given 48-72 h prior to PDT. The light source was an argon dye laser with an output beam of 630 nm. The irradiation time varied between 12 and 25 min with a fluence of 100-350 mW cm-2. The entire tumour was irradiated with a light dose of 100-250 J cm-2. The combination of UFT and mitomycin C was used as standard chemotherapy. There were 26 responders out of 55 patients (47.3%) in the group treated with PDT alone, 24 out of 41 (58.5%) in the PDT+chemotherapy group, and 24 out of 48 (50.0%) in the chemotherapy alone group. In the PDT+chemotherapy group 19.5% patients had complete remission, which was better than the other two groups (5.5%, 8.3%, p less than 0.05). The following survey of all patients lasted from six months to seven years. The results suggest that a combination of PDT and chemotherapy may prove effective.

Combined Modality Therapy↗
PubMed1992

High dose mitomycin C for treatment of advanced gastric cancer.

Thirty five patients (26 males and 9 females) with advanced gastric cancer confirmed by pathology were treated by high-dose mitomycin C. According to the following dose and schedules: Mitomycin C 20 mg intravenously per week and a total of 60 mg. Three weeks later, all the patients received FT-207 600 mg daily and a total of 20-40 g. The ages ranged from 24 to 75 years, 11 had cancer of cardia, 6 had cancer of gastric body, and 18 had cancer of gastric antrum. Eleven patients could not have an operation. Seventeen patients were recurrence of post operation. Eighteen of 35 patients received CR (7/35) and PR (11/35), the response rate was 51.43% of the responders, the median duration of remission and survival were 7.3 (range, 2-16) and 12.2 (range, 3-30) months, respectively. Common doses were instilled. The main side effects were leukopenia (10/35) and thrombocytopenia (7/35). None of these patients had liver and kidney function damage.

Adult↗