[Construction of the internal standard RNA and DNA templates for MRP gene quantitative RT-PCR analysis]

OBJECTIVE

To construct the internal standard RNA and DNA templates for quantitative reverse transcription-polymerase chain reaction (RT-PCR) and quantitatively measure the mRNA expression of MRP gene.

METHODS AND RESULTS

A 292 bp fragment was amplified by PCR from plasmid pRC/RSV-MRP containing full-length MRP cDNA and inserted into the Sma I site of PUC19 vector, constructing a recombinant plasmid-pUMRP292. A 238 bp HGV fragment was amplified by PCR from plasmid pUHGV and inserted into the Cla I site of pUMRP292, constructing a new recombinant plasmid-pUMRP 292/HGV as the internal DNA competitive template for quantitative PCR of MRP. A 530 fragment containing the 292 bp of MRP and the 238 bp of HGV was cut down by EcoR I and Xba I pUMRP292/HGV and cloned into the transcriptional vector pSP72 by the same enzyme sites, constructing a recombinant plasmid-pSMRP292/HGV, and then pSMRP292/HGV was cleaved with EcoR V and transcripted in vitro by SP6 RNA polymerase, obtaining a 530 bp mutant MRP-RNA positive strand as the internal RNA competitive template for quantitative RT-PCR.

CONCLUSION

The established quantitative RT-PCR assay is simple, rapid and sensitive, and the DNA competitive template is more simple, economic and reliable than the RNA one.

A chemically modified tetracycline inhibits streptozotocin-induced diabetic depression of skin collagen synthesis and steady-state type I procollagen mRNA

Wasting of connective tissues including skin, bone, and cartilage have been closely associated with elevated matrix metalloproteinase (MMP) activity and depressed collagen content in the streptozotocin (STZ)-induced diabetic rat, while tetracyclines have been reported to normalize total body weight, skin hydroxyproline and collagen content in this model, in part through inhibition of MMPs. In the present study, we report the effect of CMT-1, a chemically modified tetracycline that lacks antimicrobial properties but retains divalent cation binding and MMP inhibitory activity, on diabetic skin collagen synthesis and steady-state levels of procollagen alpha 1(I) mRNA. Male, 4-month old Sprague-Dawley rats received a single injection of 75 mg/kg STZ or citrate vehicle alone and diabetic status was confirmed by positive glucosuria. Some diabetic animals received 10 mg/day of CMT-1 by oral gavage and, 28 days after STZ treatment, body weight, blood glucose values and the in vivo rates of skin collagen production were measured using the pool-expansion technique. Steady-state levels of procollagen alpha 1(I) mRNA were analyzed 21 days after STZ treatment by hybridization of total RNA with a 32P labelled cDNA to rat type I procollagen alpha 1(I) mRNA in a dot-blot assay. STZ treatment was found to significantly depress body weight, skin collagen hydroxyproline content, the in vivo rate of collagen production, and hybridizable levels of type I procollagen alpha 1(I) mRNA. CMT-1 administered daily to STZ-treated rats inhibited the diabetic depression of these parameters but had little or no effect on non-diabetic controls or on STZ-induced hyperglycemia. Thus, in addition to the inhibition of MMP mediated extracellular collagen degradation, these results suggest CMT-1 also acts to inhibit diabetic connective tissue breakdown in STZ-induced diabetes by increasing both steady-state levels of type I procollagen mRNA and collagen synthesis through mechanism(s) that are independent of the antibacterial properties of tetracyclines.

Intracavity Frequency-Doubled and Frequency-Stabilized CW Ring Nd:YAP Laser

A frequency-doubled and frequency-stabilized ring Nd:YAP laser with a six-mirror cavity is demonstrated. This laser satisfies both the thermal insensitivity and optimal frequency-doubling conditions. A second-harmonic output to 1 W at 0.54 mum is achieved. The intensity fluctuation is less than ?1.5% and the frequency stability is better than ?1 MHz (5 min).

Detection of p53 gene mutations in human leukemia by PCR-SSCP analysis and direct nucleotide sequencing

OBJECTIVE

To look for mutations of the p53 gene in leukemic patients and study the relationship between abnormalities in p53 gene and leukemogenesis.

METHODS

The peripheral blood and Bone Marrow Samples were collected from 36 patients with various leukemia types including 14 cases of lymphocytic leukemia [8 cases of acute lymphocytic leukemia (ALL), 4 cases of chronic lymphocytic leukemia (CLL), 2 cases of hairy cell leukemia (HCL)] and 22 cases of myelocytic leukemia [11 cases of acute nonlymphocytic leukemia (ANLL), 11 cases of chronic myelocytic leukemia (CML)]. DNA structures of exon 5-8 of the p53 gene were scanned by PCR-SSCP (single strand conformation polymorphism analysis of polymerase chain reaction products). The appropriate DNA fragments were amplified, Purified and sequenced directly.

RESULTS

By PCR-SSCP analysis, shifts in electrophoretic mobility of the p53 gene were detected in 3 of 14 patients with lymphocytic leukemia (2 ALL and 1 CLL), but none in 22 patients with myelocytic leukemia including one in blastic crisis. Direct nucleotide sequencing in one patient with ALL showed transition of CTG to CAG at codon 257 of exon 7, resulting in a change of its encoded amino acids from aspartic acid to valine. To our knowledge, the mutation at this codon has not been previously reported hitherto.

CONCLUSIONS

The p53 gene mutations are specifically associated with lymphocytic leukemia. Alternations of the p53 gene may play a certain role in leukemogenesis in some cases of lymphocytic leukemia.

[The relationship between cytosolic Ca2+ and two kinds of granule number in activated platelets]

The numerical density (Nv) of the alpha-granule (alpha G) and dense granule (dG) measured by using electron microscopic morphometry and the cytosolic free calcium concentration ([Ca2+]i) by using Ca-fluorescent indicator were observed for studying the relationship of [Ca2+]i and Nv of alpha G and dG in platelets activated by A23187, thrombin or ADP. The results showed that the [Ca2+]i rose markedly by A23187. Thrombin or ADP could also induce an increase of [Ca2+]i concentration-dependently. Under 3 different degrees of activation induced by different agonists, the close relationship between Nv of both granules, alpha G and dG, and [Ca2+]i in platelets was found (Pr(alpha G) < 0.05, Pr(dG) < 0.01). These findings indicate that the increase in [Ca2+]i may enhance the secretion of alpha G and dG.

Determining protein-protein interactions by oxidative cross-linking of a glycine-glycine-histidine fusion protein

The Ni(II) complex of the tripeptide NH2-glycine-glycine-histidine-COOH (GGH) mediates efficient protein-protein cross-linking in the presence of oxidants such as oxone and monoperoxyphthalic acid (MMPP). Here we demonstrate that GGH fused to the amino terminus of a protein can still support cross-linking. The tripeptide was expressed at the amino terminus of ecotin, a dimeric macromolecular serine protease inhibitor found in the periplasm of Escherichia coli. In the presence of Ni(OAc)2 and MMPP, GGH-ecotin is cross-linked to give a species that has an apparent molecular mass of a GGH-ecotin dimer with no observable protein degradation. The cross-linking reaction occurs between two ecotin proteins in a dimer complex. Furthermore, GGH-ecotin can be cross-linked to a serine protease target, trypsin, and the reaction is specific for proteins that interact with ecotin. The cross-linking reaction has been carried out on small peptides, and the reaction products have been analyzed by matrix-assisted laser desorption/ionization mass spectrometry. The target of the reaction is tyrosine, and the product is bityrosyl cross-links. The yield of the cross-linking is on the order of 15%. However, the reaction efficiency can be increased 4-fold by a single amino acid substitution in the carboxy terminus of ecotin that places an engineered tyrosine within 5 A of a naturally occurring tyrosine. This cross-linking methodology allows for the protein cross-linking reagent to be encoded for at the DNA level, thus circumventing the need for posttranslational modification.

[Role of programmed cell death in mediating arsenic-induced rat embryo anomalies]

With a view to further investigating teratogenicity, embryotoxicity and teratogenic mechanism of arsenic on developing embryos, the relationship between apoptosis (programmed cell death, PCD) and arsenic-induced teratogenesis was studied during head-fold stage by using in situ 3'end-labeling of DNA and Nile blue sulfate (NBS) vital staining. Sprague-Dawley rats were intraperitoneally injected on gestation day 9.5 with doses of 0, 1, 4 and 8 mg/kg arsenic respectively, and killed at day 12, the results show that teratogenic incidence and mortality increased to 35.7% and 23.8% respectively, in apparent dose-effect relationship. In NBS staining experience, it was found that arsenic induced PCD in many areas, which related with abnormal development of brain, optic system, somite segmentation, limb bud and so on. In situ 3' end-labeling of DNA further supported above-mentioned results. The positive rate of apoptotic cell death was up to 55.6% (P < 0.05). This research suggested a positive correlation between abnormal PCD and teratogenesis. It may be seen that over-apoptosis is one of teratogenic mechanisms of arsenic. Moreover, our results show that necrosis plays some role in teratogenesis as well.

Elevation in tumour necrosis factor-alpha (TNF-alpha) messenger RNA levels in the uterus of pregnant gilts after oestrogen treatment

In pigs, induction of embryonic degeneration, by exogenous oestrogens given early in gestation, has been long recognised. However, the underlying mechanisms responsible for this degeneration remain unclear. The present study was conducted to determine whether oestrogen-induced early porcine embryonic mortality was associated with changes in the levels of tumour necrosis factor-alpha (TNF-alpha) messenger RNA in the uterine endometrium. Prepubertal gilts were induced into oestrus with PG600 and artificially inseminated at their second natural oestrus and again 24 h later. After insemination, gilts were randomly assigned to treatment and given 0.5 ml intramuscular injections of either oestradiol valerate (10 mg ml-1) or corn oil on day 9 and 10 of gestation. The gilts were slaughtered on day 12, 15 or 18 of gestation. The reproductive tract was removed from each gilt and the uterine horns were flushed to check for the presence and integrity of embryos. Samples of uterine endometrial tissues were collected, snap-frozen in liquid nitrogen and stored at -80 degrees C. Total cellular RNA was isolated from frozen tissues using a guanidine isothiocyanate-cesium chloride method. The abundance of TNF-alpha messenger RNA was determined by Northern blot hybridisation analysis. Treatment of pregnant gilts with oestrogen resulted in severe fragmentation of embryos on days 15 (2/3) and 18 (2/2), confirming the embryocidal effect of exogenous oestrogen. Uterine TNF-alpha messenger RNA level was elevated in oestrogen-treated gilts compared with controls (P < 0.05). This observation of an association between increased levels of TNF-alpha mRNA in the uterus and embryonic degeneration in oestrogen-treated gilts suggests that TNF-alpha may be involved in mediating oestrogen-induced early embryonic mortality in the pig.

SHP-1 associates with both platelet-derived growth factor receptor and the p85 subunit of phosphatidylinositol 3-kinase

The Src homology 2 (SH2)-containing protein tyrosine phosphatase 1, SHP-1, is highly expressed in all hematopoietic cells as well as in many non-hematopoietic cells, particularly in some malignant epithelial cell lines. In hematopoietic cells, SHP-1 negatively regulates multiple cytokine receptor pathways. The precise function and the targets of SHP-1 in non-hematopoietic cells, however, are largely unknown. Here we demonstrate that SHP-1 associates with both the tyrosine-phosphorylated platelet-derived growth factor (PDGF) receptor and the p85 subunit of phosphatidylinositol 3-kinase in MCF-7 and TRMP cells. Through the use of mutant PDGF receptors and performing peptide competition for immunoprecipitation, it was determined that SHP-1 independently associates with the PDGF receptor and p85 and that its N-terminal SH2 domain is directly responsible for the interactions. Overexpression of SHP-1 in TRMP cells transfected with the PDGF receptor markedly inhibited PDGF-induced c-fos promoter activation, whereas the expression of three catalytically inactive SHP-1 mutants increased the c-fos promoter activation in response to PDGF stimulation. These results indicate that SHP-1 might negatively regulate PDGF receptor-mediated signaling in these cells. Identification of the association of SHP-1 with the PDGF receptor and p85 in MCF-7 and TRMP cells furthers our understanding of the function of SHP-1 in non-hematopoietic cells.

Combinatorial search for diagnostic agents: Lyme antibody H9724 as an example

Two peptide libraries, Ac-MXXXXXBBRM and Ac-VXXXXXBBRM, were constructed on TentaGel solid support to search for ligands that bind tightly with the H9724 Lyme antibody. By using an on-bead ELISA, approximately 120 ligands were selected as candidates for further study. Matrix-assisted laser desorption ionization mass spectrometry analysis of the candidate ligands indicated a high rate of occurrence of certain amino acids at the randomized positions. On the basis of the initial screening results, a small library was designed and iteratively synthesized. Subsequent library screenings led to the identification of four peptides, Ac-PQEEGX-NH2 (X = R, K, A, D), that showed specific affinity to the antibody. This combination of solid-phase screening and iterative synthesis is an effective strategy for rapid identification of ligands that bind tightly with disease-specific antibodies and should be applicable, at least in principle, to other ligand-receptor systems. This combinatorial library approach can also be a useful tool for the discovery of novel diagnostic agents.

[Expression characteristic of Bacillus thuringiensis cry1 gene in Pseudomonas fluorescens Pfx-18]

The plasmids of lepidopteran-specific Bacillus thuringiensis strain from our laboratory were hybridized with RNA probe of cry 1Aa EcoR I-F fragment labelled using DIG. Cry1 gene was located in 39.3 MD plasmid. The plasmid was digested with Hind III and analysed by southern blot. It appeared both 7.1 kb and of 6.5 kb positive bands. The 7.1 kb fragment was ligated to broad-host-range vector pSUP106 and transformed into Pseudomonas fluorescens Pfx-18. The cloned strain, LZP-1 was obtained. The plasmids of LZP-1 were analysed by PCR. The results showed that gene-type is cry1Ab. SDS-PAGE analysis demonstrated that LZP-1 could express 66 kD insecticidal crystal protein and some small molecular weight peptides. Bioassay showed that motality of 1000-fold diluted fermentation broth was 33% to 3rd instar plulella xyloslelly larvae.

[Comparison of prognosis between inguinal cryptorchic seminoma and scrotal seminoma]

OBJECTIVE

To analyse the prognosis of patients with inguinal cryptorchic seminoma.

METHODS

From 1985 through 1991, 43 patients with inguinal seminoma of undescended testis were treated and the therapeutic effect retrospectively reviewed. There were 33 patients in stage I, 8 in stage II, 1 in stage III, and 1 in stage IV. All patients had inguinal orchiectomy. Patients in stage I and II were primarily treated with radiotherapy, whereas one patient in stage III and another in stage IV were treated with radiotherapy or chemotherapy.

RESULTS

The 5- and 10-year overall survival was 93.0% and 90.3%, respectively. The corresponding disease-free survival was 88.1% and 85.3%, respectively. The overall 5- and 10-year survival by stage was 100% and 100% for stage I, 75.0% and 60.0% for stage II, respectively. Two patients relapsed and were successfully treated with radiotherapy.

CONCLUSION

Prognosis for inguinal cryptorchic seminoma is as good as that of scrotal testicular seminoma. Postorchiectomy radiotherapy encompassing para-aortic and ipsilateral iliac nodes is effective for stage I and early stage II inguinal crytorchic seminoma. The inguinal nodes should be included in the treatment ports only when they are involved or if there is obvious involvement of surrounding tissues by the primary tumor.

An HLA-restricted, p53 specific immune response from HLA transgenic p53 knockout mice

BACKGROUND

p53 is over-expressed in most human malignancies and is therefore an attractive target for immunotherapy. Unfortunately, a human cytotoxic T cell response to p53 is difficult to generate. p53 knockout transgenic mice may provide a model to circumvent immunologic tolerance to p53 and develop high-affinity p53-specific cytotoxic T lymphocytes (CTL).

METHODS

p53 knockout, HLA A2.1 transgenic mice were generated and immunized with the immunodominant wild-type p53 nonamer peptide epitope p53149-157. Two weeks later splenocytes were harvested and stimulated in vitro with acid-treated, p53 peptide-pulsed syngeneic blast cells. Cultures were restimulated weekly with acid-treated, p53 peptide-pulsed Jurkat cells transfected with the HLA A2.1 gene. Peptide-specific cytotoxic activity was measured by chromium release assay, and the resulting CD8+ effectors were cloned via limiting dilution.

RESULTS

P53 peptide-specific CTL were generated against p53149-157. Clones generated from the p53149-157 cell line demonstrated high affinity and specificity for p53149-157 when presented by HLA A2.1+ antigen-presenting cells. The p53149-157 CTL killed only cells overexpressing p53 cells that were HLA A2.1+ and did not kill cells with normal levels of p53 expression or those that were HLA A2.1-.

CONCLUSION

HLA transgenic mice not previously exposed to the p53 protein provide a useful model for generating high-affinity p53-specific CTL.

Evaluation of liquid chromatographic behavior of restricted-access media precolumns in the course of direct injection of large volumes of plasma samples in column-switching systems

The chromatographic behavior of an alkyl-diol silica (ADS, 25 x 4 mm I.D.) and a semipermeable surface (SPS, 10 x 10 mm I.D.) supports two types of restricted-access media (RAM), which served as precolumns in column-switching systems for direct injection of large volumes of plasma samples (500 microl), was studied with regard to peak performance, retention and column back pressure. The adsorption of matrix proteins both on sealings (porous frits and sieves) and packings was also examined. Columns of ADS and SPS were unchanged after the injection of 10-20 ml human plasma under normal working conditions. Even when changes occurred on the precolumns (>50 ml of plasma in total), it was still possible to regenerate the column performance by replacing the column sieves, or by washing and removing columns from the system for a period, since the changes were more related to the blockage of sealings and/or the adsorption of proteins on the hydrophilic surfaces. Proteins could eventually be unspecifically adsorbed on the hydrophobic ligand of the support. It was found on one ADS column that the retention decreased by 20% and the pressure increased 30 bar after an intensive loading of 75 ml plasma (injection volume, 500 microl) without reconditioning procedure. Studies showed that the column sealings played the most important role for the lifetime of RAM columns. For ADS columns, using sieves without polytetrafluoroethylene (PTFE) nets were the best. No significant difference in column life span between SPS and ADS was found.

Testosterone pharmacokinetics after application of an investigational transdermal system in hypogonadal men

This open-label, randomized, placebo lead-in, three-treatment crossover study in 19 hypogonadal men (27-82 years of age) evaluated dose proportionality of serum testosterone concentrations with application of one or two investigational transdermal testosterone systems for application to the arm or torso. Testosterone in vivo kinetics profiles were determined using DeMonS, a recently developed numerical deconvolution method that estimates drug absorption at different time intervals and/or drug disposition model parameters. After application of the investigational transdermal systems, the mean serum testosterone, dihydrotestosterone, estradiol, and free testosterone concentrations were elevated to normal levels. Treatment allowed approximation of the normal circadian pattern of endogenous testosterone secretion, and the increase in serum testosterone concentrations was proportional to the surface area of systems applied. The investigational transdermal system provided effective testosterone replacement therapy as judged by pharmacokinetic parameters.

[A laplace transform method for analysis of fluorescence dynamics]

A Laplace transform formula is developed for analysis of a multi-exponential fluorescence dynamic process. A dynamic spectrum function is introduced, calculation of which directly yields parameters of the corresponding dynamic process. The formula is applied to analyze fluorescence dynamics of beta subunit from R-phycoerythrin. It is demonstrated that electronic excited-states of the biomolecular system exhibit two exponential decay processes, the faster of which relates to excitation equilibrium among chromophores, and the slower to radiative relaxation of the chromophores.

[Protective effect of paeonol on repeated cerebral ischemia in rats]

Protcective effect of paeonol was observed in the repeated cerebral ischemia-reperfusion model in rats. Paeonol (100, 50 mg/kg x 7 d i.p.) could inhibit the increase of Ca2+, the decrease of superoxide dimutase (SOD) activity and the content of malondialdehyde (MDA), improve Ca(2+)-ATPase activity in ischemia brain tissue. The results showed that paeonol could protect cerebral ischemia by inhibiting accumulation of Ca2+ and production of oxygen free radical.

Structural characterization of human hemoglobin crosslinked by bis(3,5-dibromosalicyl) fumarate using mass spectrometric techniques

Diaspirin crosslinked hemoglobin (DCLHb) was analyzed by mass spectrometric-based techniques to identify the protein modifications effected by the crosslinking reaction with bis(3,5-dibromosalicyl) fumarate. DCLHb consists of two principal components. These components were isolated by size-exclusion chromatography and identified by measurement of their molecular weight using electrospray mass spectrometry and subsequent peptide mass mapping and mass spectrometric sequence analysis of their individual digests. Three major RP-HPLC fractions were observed from the major hemoglobin in DCLHb. Their MWs matched the MW of heme, intact hemoglobin beta-chain, and two hemoglobin alpha-chains crosslinked by a fumarate moiety, respectively. The minor HPLC peaks of DCLHb were also separated, and characterized by mass spectrometric methods. These minor components revealed additional details of the structural nature of covalent modification of DCLHb.

Effect of exogenous progesterone following mating on embryo survival in the gilt

At first observed estrus (day 0), 85 Yorkshire × Landrace gilts were artificially inseminated and assigned to receive daily injections of 50 mg progesterone from 2 to 14 d (n = 31), 4 to 14 d (n = 26) or to serve as controls and receive injections of oil from 2 to 14 d (n = 28). Gilts were slaughtered 25 to 28 d after breeding for determination of embryo survival. Supplemental progesterone had no effect on embryo survival. Key words: Gilt, embryo, progesterone

Transdermal testosterone administration in hypogonadal men: comparison of pharmacokinetics at different sites of application and at the first and fifth days of application

In this study of 13 hypogonadal men (25-69 years of age), three open-label, randomized treatments were administered to determine the pharmacokinetics of serum testosterone after application of an investigational testosterone transdermal system to the upper buttocks, upper arm, and back. Testosterone in vivo input kinetics profiles were estimated by DeMonS, a recently developed numerical deconvolution method for estimating drug absorption at different time intervals and/or drug disposition model parameters, and compared on the first and fifth days of system application. Area under the concentration-time curve from 0 to 27 hours (AUC0-27) values for testosterone after one-day applications to the upper buttocks, upper arm, and back were 9,560 ng.hr/dL, 8,651 ng.hr/dL, and 8,988 ng.hr/dL, respectively. Maximum observed concentration (Cmax) values were 482 ng/dL, 462 ng/dL, and 499 ng/dL, respectively. Serum testosterone concentrations were equivalent to each other, and Cmax values fell within the normal range. No drug accumulation was seen with repeated dosing over 5 days.

Confirmation of cross-reactivity between Lyme antibody H9724 and human heat shock protein 60 by a combinatorial approach

A library of Ac-XXXXXPAPRM decapeptides was prepared on a TentaGel solid support using the approach of split synthesis and the strategy of partial chain termination. Epitope screening of the library (17(5) approximately 1.4 x 10(6) decapeptides) with a Lyme monoclonal antibody (H9724) and subsequent MALDI-MS analysis of candidate peptides from colored beads revealed a consensus structure of Xi-DLSXj (Xi = V, L, Y; Xj = G, R). These identified sequences presented no homology to the natural epitope from Borrelia burgdorferi flagellin. However, they were found to resemble a fragment at the N-terminus of human heat shock protein (Hsp60). Our results confirmed that H9724 cross-reacts between bacterial and human proteins and provided support for an autoimmunity mechanism of Lyme disease.

DNA immunization of neonates induces immunity despite the presence of maternal antibody

Neonatal animals were not considered as suitable vaccine recipients either because of immune immaturity or because passively delivered antibody interferes with immune induction. In this report, we evaluated the response of neonatal mice to immunization with naked DNA encoding a herpes simplex virus (HSV) protein, and determined if maternally derived HSV antibody interfered with immunogenicity. Our results show that neonatal mice develop effective humoral and T cell responses after immunization with either DNA or inactivated vaccines. The nature of the responses to HSV immunization, however, was more Th2-like in neonates than in adults. Whereas neonatal mice from HSV-naive mothers responded well to both DNA and inactivated vaccines, only DNA immunization induced effective immunity in neonates born to immune mothers. Our results indicate that DNA vaccines might provide a useful means of immunizing young animals that still possess high levels of potentially interfering maternal antibody.

Alkylation of a catalytic aspartate group of the SIV protease by an epoxide inhibitor

Specific irreversible inhibition of the SIV protease by FMOC-protected piperidine epoxide 1 involves alkylation of the protein. Tryptic digestion of the alkylated protein and mass spectrometric analysis of the peptides identify an active site aspartic acid (Asp-25) as the single residue that is alkylated. Computer modeling of 1 bound in the crystal structure of the SIV protease using DOCK 3.5 indicates that 1 has appropriate access to the active site. It is able to align in an orientation that allows a proton to be transferred to the epoxide from one of the catalytic aspartic acid groups in conjunction with nucleophilic attack on the epoxide of the carboxylate moiety of the second catalytic aspartic acid residue. Hydrophobic interactions are not optimal for this process due, in part, to the rigidity of the inhibitor ring system and the planar conformation of the amide. The combination of modeling with protein alkylation can provide insights into structural modifications of the inhibitor that may lead to improved inhibitory activity.

Characterization of a cellular RNA that activates PKR in 3T3-F442A cells

The double-stranded RNA dependent eIF-2 alpha kinase (PKR) has been implicated in the regulation of a number of cellular processes including cell growth and differentiation. Previous studies using embryonic mouse 3T3-F442A cells have indicated that PKR undergoes phosphorylation and activation in vivo. This activation of PKR has been attributed to a subset of poly(A)(+)-rich cellular RNA (R-RNA) having sufficient secondary structure to interact with the kinase. To characterize the R-RNA activity, a cDNA was prepared which, when transcribed in vitro, gave rise to an RNA transcript that retained its property to activate PKR. The ability of the transcript to activate PKR was sensitive to ribonuclease V1 and was abolished by the addition of high concentrations of poly(I).poly(C). The cloned cDNA was utilized for liquid RNA/DNA hybridization experiments, which disrupted the secondary structure of the R-RNA and for Northern blot analysis. The results from these studies indicated that the measurable RRNA activity was represented in a specific cellular RNA which was responsible for the activation of PKR. Furthermore it was found that the R-RNA was specifically associated with PKR and that this complex could be detected directly in cell extracts. The nucleotide sequence of the cDNA was determined. We propose that this novel cellular RNA may play a critical role in regulating the activation of PKR and thus be an important component in the control of cell growth and differentiation.

[Effects of Puerariae isoflavone on blood viscosity, thrombosis and platelet function]

Puerariae isoflavone (500, 1000 mg/kg% x 7 d, p.o.) significantly lowered blood viscosity and platelet adhesion rate, inhibited thrombosis and ADP-induced platelet aggregation in rats, and showed obvious antagonism for platelet thrombosis in ADP-treated mice.

[Comparative study on the lysis of leukemia cells by IL-2 activated bone marrow and cord blood]

OBJECTIVE

To explore the antitumor activity of IL-2 activated bone marrow (ABM) and cord blood (ACB) mononuclear cells.

METHODS

The antitumor activity of ABM and ACB mononuclear cells to the K562 (NK sensitive) and HL-60 (NK resistant) cells was studied by 3H-TdR release assay and semisolid culture method. The progenitor cell activity (PCA) of ABM and ACB was also assayed.

RESULTS

After coculturing for 24 hrs with IL-2, the tumor-killing activities of ABM to K562 cells and to HL-60 cells were identical, while the activity of ACB to K562 cells was higher than that to HL-60 cells. After 72 hr coculturing, the activities of ABM to K562 and HL-60 cells were still higher than that of ACB. The optimum conditions for the activation of ABM and ACB were 1000U/ml IL-2, 1 x 10(6)/ml cells, 100 : 1 effector to target ratio and 72 hr culturing. PCA was not affected after IL-2 activation, while the immunophenotypic markers changed greatly. TNFalpha and IL-6 were detectable after culturing for 24 hrs, and went higher at 72 hrs. Large granular lymphocytes were generated both in cord blood and bone marrow after 24 hr culturing with IL-2.

CONCLUSION

Both bone marrow and cord blood could be activated by IL-2 and gained cytotoxic effects, but the cytotoxicity of ACB was slightly lower than that of ABM under the same culturing condition. The mechanism of cytotoxicity might be cell mediated cytotoxicity and releasing of cytokines such as TNFalpha and IL-6.

[Effects of yizhi pills on memory, superoxide dismutase and malondialdehyde of brain and immunity in mice]

Passive avoidance tests have shown that Yizhi Pills (YZ) markedly improve the memory of normal mice at a dose of 100 mg/kg after oral administration for fifteen days, and significantly reverse the scopolamine, NaNO2 and EtOH-induced disruptions of memory retention in mice at doses of 100, 200, 500 mg/kg after oral administration for five days. In aged mice induced by D-galactose, YZ also significantly improve the impaired memory, increase the activity of SOD and decrease the content of MDA in brain. All these effects were observed at doses of 200, 500 mg/kg after oral administration for forty-one days. YZ significantly promote blood carbon particle clearance, enhance hemolysin antibody in immunodepressed mice induced by cyclophosphamide, and increase earswelling in immunodepressed mice induced by prednisolonum.

DeMonS--a new deconvolution method for estimating drug absorbed at different time intervals and/or drug disposition model parameters using a monotonic cubic spline

DeMonS-a new numerical deconvolution method for estimating the amount of drug absorbed at different time intervals and/or drug disposition model parameters-is presented here. In DeMonS, the amount of drug absorbed at different time intervals and/or drug disposition model parameters are the unknown parameters to be calculated. The Fritsch-Butland non-decreasing cubic spline was constructed from the cumulative amount of drug absorbed-time data directly derived from the calculated amount of drug absorbed at different time intervals. The drug absorption rate, which is the derivative of this non-decreasing cubic spline, is therefore represented by a piecewise non-negative quadratic function. The drug concentrations were obtained by convoluting the drug absorption rate quadratic function with the drug disposition model function. The nonlinear optimization method with simple parameter bounds was used to estimate the optimal set of unknown parameters by minimizing the sum of squares of residuals between the observed and predicted drug concentrations. DeMonS has been applied to (i) the griseofulvin data for estimating drug absorbed at different time intervals when the drug disposition model parameters were determined separately from intravenous data, (ii) veralipride double-peak phenomenon data to estimate simultaneously the percentage of cumulative veralipride absorbed and the veralipride disposition model parameters without reference intravenous data, (iii) a comparative bioequivalence study of gastrointestinal therapeutic system (GITS) pseudoephedrine HCI (PeHCI) controlled-release oral dosage forms when the drug disposition model parameters were not available, and (iv) estimation of both drug disposition model parameters and the absorption rate of drug from Testoderm (testosterone transdermal system) in the presence of endogenous testosterone production. DeMonS was implemented using MATLAB and NAG MATLAB Toolbox, and is available for Windows 3.1.

A minK-HERG complex regulates the cardiac potassium current I(Kr)

MinK is a widely expressed protein of relative molecular mass approximately 15K that forms potassium channels by aggregation with other membrane proteins. MinK governs ion channel activation, regulation by second messengers, and the function and structure of the ion conduction pathway. Association of minK with a channel protein known as KvLQT1 produces a voltage-gated outward K+ current (I[sK]) resembling the slow cardiac repolarization current (I[Ks]). HERG, a human homologue of the ether-a-go-go gene of the fruitfly Drosophila melanogaster, encodes a protein that produces the rapidly activating cardiac delayed rectifier (I[Kr]). These two potassium currents, I(Ks) and I(Kr), provide the principal repolarizing currents in cardiac myocytes for the termination of action potentials. Although heterologously expressed HERG channels are largely indistinguishable from native cardiac I(Kr), a role for minK in this current is suggested by the diminished I(Kr) in an atrial tumour line subjected to minK antisense suppression. Here we show that HERG and minK form a stable complex, and that this heteromultimerization regulates I(Kr) activity. MinK, through the formation of heteromeric channel complexes, is thus central to the control of the heart rate and rhythm.

Neurokinin-1 receptor antagonist SR140333: a novel type of drug to treat cerebral ischemia

Substance P (SP) has been implicated in immune responses and could increase glutamate release, and inflammatory reactions are known to be able to potentiate ischemic damage. We have previously found that SP was over-expressed in cerebral ischemia and speculated that SP may play a role in exacerbating ischemic damage. In this study, we examined whether a neurokinin-1 (NK-1) receptor antagonist, SR140333, would have an effect on brain ischemia. Intra-cerebroventricular (i.c.v.) administration of SR140333 (30 micrograms) markedly reduced (37.1 +/- 7.8%, p < 0.001) infarct volume measured 24 h after focal cerebral ischemia in the rat. The SR140333-treated group also exhibited a significantly improved neurological function reflected by the neurological deficit score. The results represented the first demonstration that a NK-1 receptor antagonist may be a novel type of drug for treatment of cerebral ischemia.

[Comparison on pharmacological functions of pheretima]

Hot water extraction of Pheretima have marked actions in antipyretic, hypotensive, antiasthmatic and diuresis. Among them Guang-Pheretima and Hu-Pheretima are stronger than Tu-Pheretima in antipyretic. The difference of the intensity of Pheretima in the other actions is not obvious.

The study of IL-1 beta, TNF-alpha, IL-6 gene expression and plasma levels on hemodialysis before and after dialyzer reuse

OBJECTIVE

To investigate the biocompatibility of dialyzer reuse.

METHODS

Twenty-two hemodialysis patients were randomized into cuprophan (CU, 7), polymethylmethacrylate (PMMA, 7) and polysulphone (PS, 8) membrane groups to observe IL-1 beta, TNF-alpha, IL-6 gene expression and their plasma levels by using themselves as control with enzyme-linked immunosorbent assay (ELISA), reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization.

RESULTS

Plasma levels of interlukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) were 14.07 +/- 3.32 pg/ml, 67.41 +/- 19.79 pg/ml, 83.67 +/- 40.34 pg/ml; 12.80 +/- 3.01 pg/ml, 49.65 +/- 9.75 pg/ml, 33.36 +/- 12.14 pg/ml and 14.41 +/- 3.16 pg/ml, 80.56 +/- 23.22 pg/ml, 48.14 +/- 16.01 pg/ml, respectively, after patients dialyzed with CU, PMMA and PS membranes. Plasma cytokine levels decreased after reuse compared with those before reuse in each group. But no significant difference was found between them (P > 0.05); the levels of IL-1 beta, TNF-alpha, IL-6 gene expression after reuse were 5.61 +/- 0.33, 2.11 +/- 0.12, 5.04 +/- 0.19%; 2.43 +/- 0.19, 1.29 +/- 0.11, 3.48 +/- 0.20% and 2.48 +/- 0.20, 1.24 +/- 0.11, 3.22 +/- 0.20% respectively by in situ hybridization, and 0.92 +/- 0.07, 0.63 +/- 0.05, 0.53 +/- 0.05; 0.61 +/- 0.06, 0.47 +/- 0.04, 0.37 +/- 0.03 and 0.59 +/- 0.05, 0.44 +/- 0.04, 0.38 +/- 0.03 by RT-PCR, respectively. After reuse there was significant decrease as compared with that before reuse (P < 0.001, P < 0.005 and P < 0.05, respectively).

CONCLUSIONS

This suggested reprocessing dialyzer with formaldehyde reduced cytokine release and gene expression in peripheral blood mononuclear cells and enhanced dialyzer biocompatibility. It would be beneficial to reduce the dialysis cost and may reduce the complication related to a long term hemodialysis.

[Meningo-cerebral arteriovenous malformations]

22 patients with meningo-cerebral arteriovenous malformations, we treated in our hospital between 1990 and 1995. Clinical manifestations included headache, nausea, seizure, intracranial hemorrhage, and progressive hemispheric neurologic deficits. The niduses were extensive and had dual feeding from internal and external carotid arteries. All patients underwent endovascular treatment and 4 surgical operations. The curative effect was satisfactory. The clinical and angiographic characteristics were discussed.

[Adaptation of myocardial function to simulated weightlessness]

To observe the changes in myocardial function and calcium ion release of sarcoplasmic reticulum in rats under simulated weightlessness, 24 Sprague-Dawley male rats were divided into control (CON), 8 week tail-suspension (SUS) and recovery for 2 weeks (RE) groups. The results showed that there was no change in resting tension of myocardial twitch in SUS. While the developed tension (DT) of myocardial twitch significantly decreased in SUS as compared with CON. The time to peak tension (TPT) and time to half relaxation (T1/2R) of myocardial twitch were prolonged in SUS. DT, TPT and T1/2R recovered to their corresponding control values after 2 w of recovery from tail-suspension. The early recovery curve of force-interval relation in SUS was in a higher position over that of CON, but the rest potentiation and rest depression curve was positioned under that of CON. These results suggested that there might be an adaptative change in myocardial function in medium- or long-term tail-suspended rats while 8 w tail-suspension reduces calcium ion release from cardiac sarcoplasmic reticulum in rats.

[Study on the relationship between intratumor microvessel density and neck metastasis of laryngeal and hypopharyngeal squamous cell carcinomas]

Sixty-one laryngeal and hypopharyngeal squamous cell, carcinoma (LC, HPC) tissue slides were immunochemically stained using LSAB method to study epithelium cells. The results demonstrated that (1) intratumor microvessel density (ITMD) in LC and HPC group was higher than that of the benign group (P < 0.05). ITMD was higher in the subgroup of LC and HPC with positive lymph node positive than that with negative lymph nodes. This result suggest that ITMD is relevant not only to the nature of the tumor, but also to lymph node metastasis. The level of ITMD is an important predictive sign of metastasis. (2) The relationship between ITMD and the clinical staging had no statistic significance (P > 0.05). (3) The analysis on the relationship between ITMD and pathologic differentiation indicated that the level of ITMD raised gradually with the lowering of the pathologic differentiation.

Effects of superoxide anion, B(alpha)P and TPA on the membrane fluidity of NIH3T3 cells

The membrane fluidity of NIH3T3 cells treated with low and high concentration of cell stimulatives (extracellular generated superoxide anion(O2-.),12-O-tetra-decanoyl-phorbol-13-acetate(TPA), and benzo(alpha)-pyrene[B(alpha)P]) was investigated by means of fluorescence labels 1,6-diphenyl-1,3,5 hexatriene (DPH) and N-(3-pyrene) maleimide (N(3p)M). The high concentration of O2-., TPA, B(alpha)P greatly increased the fluidity of cell membrane lipid domain. No changes of the florescence polarization of DPH was found in membrane lipid domain treated with low concentration of O2-., TPA, and B(alpha)P. However, decrease in the fluoresence polarization of N(3p)M on the cell membrane protein domain damaged by low concentration of cell stimulatives was observed, showing that these treatment could influence the conformation of membrane protein. The possible relationship between the changes of the conformation of membrane protein and the cell transformation and its carcinogenic machenisms were discussed.

[Virological and clinical features of patients with sporadic hepatitis C]

In this study, the transmission route in 16 sporadic hepatitis C (SHC) patients was investigated. Three of them were surgeons who had often had occupational needlestick accidents, another 3 had close household contact with their spouses who had been diagnosed as chronic posttransfusion viral hepatitis C (PTHC), and the remaining 5 had potential parenteral exposure such as tooth extraction, injection or inoculation and so on. Five patients with SHC didn't have such history, their transmission route was not determined. Our result showed a lower viremia level in patients with SHC when compared to PTHC patients (the serum dilutions for HCV RNA detection was 10-100 times in the former and 100-10000 times in the latter. P<0.01). Only 1 patient with SHC was anti-HCV positive. Comparing to PTHC, the patients with SHC in our study had milder liver demage and lower ALT levels, and most of them (10/16) were symptomless.

The use of transgenic mice to generate high affinity p53 specific cytolytic T cells

P53 is an attractive target immunotherapy because it is overexpressed in up to one half of all malignancies, and its overexpression often correlates with a worsened prognosis. We wanted to determine the feasibility of targeting wild-type epitopes p53 on human tumor cells. HLA A2.1 transgenic mice were immunized with the immunodominant wild-type p53 peptide epitopes, p53(149-157) and p53(264-272), along with a pan-DR helper epitope peptide in incomplete Freund's adjuvant (IFA). Twelve days later, splenocytes were harvested and stimulated with syngeneic blast cells that had been acid-treated to remove endogenous peptide and p53 peptide-pulsed. The responding cells were subsequently restimulated weekly with acid washed, peptide-pulsed Jurkat cells transfected with HLA A2.1. Peptide specific activity was tested in a chromium release assay. The resulting cytotoxic T cells (CTL) were cloned by limiting dilution. Peptide specific CTL were generated against both p53(149-157) and p53(264-272. Only p53(149-157) specific CTL were able to recognize and lyse cells that overexpressed endogenous p53. CTL clones derived from the p53(149-157) cell line demonstrated high affinity and specificity for p53(149-157) when presented by HLA A2.1+ cells. The p53(149-157) specific CTL were tested for specificity against a variety of cultured human cell lines. The CTL clones only lysed cells that overexpressed p53 in the context of HLA A2.1 and did not lyse cells with normal p53 expression or cells that lacked HLA A2.1 expression. This study demonstrates the possibility of targeting tumors, which overexpress p53, and raises the possibility transferring the high affinity, p53 specific T cell receptors from the murine CTL to human T cells.

[Pharmacological study on the compatibility of cortex Cinnamomi with Halloysitum Rubrum]

The decoction of Cortex Cinnamomi (CC, 1 g/kg p.o.) and Halloysitum Rubrum (HR, 3 g/kg p.o.) or the combination of the two drugs (4 g/kg p.o., CC 1 g/kg, HR 3 g/kg) could antagonize the diarrhea caused by p.o. water ex tract of Radix et Rhizoma Rhei in mice; and inhibit the platelet aggregation induced by ADP in vitro. Meanwhile, the effect of the combination of the two drugs was not different from that of each single one. In addition, CC was able to inhibit the spontaneous movement of intestine in situ and showed an analgesic effect (hot-plate method) in mice; HR was ineffective in these aspects and did not reduce the effect of CC. CC(20 g/kg p.o., i.p. or i.v.) exhibited very strong toxicity in mice, while HR(60 g/kg p.o., i.p. or i.v.) was nontoxic. When the two drugs were used together, the toxicity was markedly reduced.

A low molecular weight substance purified from human placenta inhibits cAMP-dependent protein kinase and activates protein kinase C

We have purified from human placenta a low molecular mass substance that inhibits cAMP-dependent protein kinase and activates protein kinase C. This protein kinase regulator was purified in three steps: (1) homogenizing placentas in chloroform/methanol and extracting the regulator into water; (2) eluting a strong anion exchange high performance liquid chromatography (HPLC) column with a quaternary gradient; and (3) eluting a reversed-phase HPLC column with a binary gradient. The regulator was found to be highly purified by HPLC, thin-layer chromatography (TLC) and laser desorption ionization mass spectrometry with a molecular mass of 703 Daltons by the latter procedure. The physical and biochemical properties of this protein kinase regulator suggest that it is a phospholipid but it did not co-elute by HPLC or by TLC with any of the known phospholipid activators of protein kinase C.

Suppression of pentylenetetrazol-induced seizures by carnitine in mice

When ddY mice were pretreated with L-carnitine (5, 10 or 20 mmol/kg), clonic as well as tonic seizures induced by pentylenetetrazol (PTZ) were dose-dependently suppressed. A time/response study (PTZ was injected 1, 5, 15 or 30 min after L-carnitine) showed that the anticonvulsive effects were apparent when the interval between L-carnitine and PTZ administration was 15-30 min. Saline containing 43% sucrose prolonged the latency to the first clonic seizure but was less effective than 20 mmol/kg L-carnitine and did not suppress clonic or tonic seizures. Alterations in brain energy metabolites caused by PTZ including increase of lactate and decrease of ATP and phosphocreatine were also suppressed by L-carnitine. L-carnitine was more potent than D-carnitine in prolonging the latency to the first clonic seizure and in decreasing the frequency of clonic as well as tonic seizures. The anticonvulsive effects of L-carnitine in PTZ-induced seizures may be unrelated to the transport of long-chain acyl CoA since they were not interfered with by D-carnitine.