[A randomized controlled study of ligustrazine in combination with propranolol for prevention of recurrent esophageal varices bleeding]

OBJECTIVE

To assess the efficacy of Ligustrazine in combination with propranolol in the prevention of recurrent esophageal varices bleeding following liver cirrhosis, and its act mechanism.

METHODS

A prospective controlled study was conducted on 74 patients, in whom 38 belonged to treatment group, and 36 to control group. By detecting the portal system hemodynamics in patients with portal hypertension and esophageal varices using color Doppler ultrasound technique, the therapeutic efficacy and safety were investigated. Meanwhile the blood pressure, heart rate, hepatic and renal function were dynamically observed.

RESULTS

After four weeks administration of the drugs, the flow of portal vein and splenic vein, the diameter of portal vein and splenic vein in the treatment group were significantly decreased with the values of 1152.36A387.46 ml/min, 529.35A326.31 ml/min, 1.36A0.28 cm, and 0.94A0.19 cm, respectively. No adverse effect was observed on the system circulation and the liver function. In the follow-up period of two years, the rebleeding rate and mortality rate in the placebo group were higher than that in the treatment group, but patients with liver cirrhosis Grade C in the two groups were not significant different.

CONCLUSION

Low dose ligustrazine plus propranolol is a safe and effective therapy in preventing recurrent esophageal varices bleeding, and worth further trial.

[The difference of thrombin-induced TF/uPAR mRNAs expressions in cultured endothelial cells and U937 cell line]

OBJECTIVE

To compare the effects of thrombin on the expression of the tissue factor (TF) and urokinase-type plasminogen activator receptor (uPAR) mRNA in the cultured vascular endothelial cells (VEC) and U937 cell line.

METHODS

Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to detect the mRNA levels of TF and uPAR genes in the cultured cells under stimulation of thrombin, inactivated thrombin (DFP-T), or at the presence of the inducers and anti-thrombin receptor antibody (ATR-Ab).

RESULTS

In U937 cells, the TF and uPAR mRNA expression induced by thrombin could be fully quenched with the ATR-Ab, but in VEC, even at the presence of ATR-Ab, there still was a little stimulative effect of thrombin revealed. DFP-T had no effect on the expression of TF and uPAR mRNA in U937 cells, but could elicit a faint reaction in VEC.

CONCLUSION

The induction effects on TF and uPAR mRNA expression in both of the cultured cells by thrombin were mainly dependent on the TR activation, which may not be the unique pathway for thrombin to induce TF and uPAR mRNA expression in VEC.

Mitochondrial aconitase gene expression is regulated by testosterone and prolactin in prostate epithelial cells

BACKGROUND

m-aconitase catalyzes the first step leading to the oxidation of citrate via the Krebs cycle. It is a constituitive enzyme in virtually all mammalian cells, found in excess, and is considered to be a regulatory or regulated enzyme. In contrast to these general relationships, prostate secretory epithelial cells possess a uniquely limiting mitochondrial (m-) aconitase which minimizes the oxidation of citrate. This permits the unique prostate function of accumulating and secreting extraordinarily high levels of citrate. Previous animal studies demonstrated that testosterone and prolactin regulate the level of m-aconitase specifically in citrate-producing prostate cells. The present studies were conducted to determine if testosterone and prolactin regulated the expression of the m-aconitase gene in prostate cells, and to determine the effect of the hormones on human prostate cells.

METHODS

The studies were conducted with freshly prepared rat ventral, rat lateral, and pig prostate epithelial cells, and with the human malignant cell lines LNCaP and PC-3. The effects of 1 nM testosterone and 3 nM prolactin on the level of m-aconitase mRNA and on the transcription rate of m-aconitase were determined.

RESULTS

The studies revealed that both prolactin and testosterone increase the levels of m-aconitase mRNA and the transcription rates of m-aconitase in rat ventral prostate cells, pig prostate cells, and human malignant prostate cells (LNCaP and PC-3). In contrast, both hormones decreased the level of m-aconitase mRNA and repressed m-aconitase gene transcription in rat lateral prostate cells. The hormonal regulation of m-aconitase corresponded with the levels of m-aconitase enzyme, m-aconitase activity, and citrate oxidation.

CONCLUSIONS

In addition to the constitutive expression of m-aconitase, the m-aconitase gene is testosterone- and prolactin-regulated in specifically targeted prostate cells. The hormonal regulation of m-aconitase gene expression and biosynthesis of m-aconitase provide a regulatory mechanism for the oxidation of citrate, and consequently, the level of net citrate production by prostate. The hormonally increased expression and biosynthesis of m-aconitase in human malignant cells might be involved in the increased citrate oxidation associated with the development of true malignant cells in prostate cancer.

Structure of Aspergillus niger epoxide hydrolase at 1.8 A resolution: implications for the structure and function of the mammalian microsomal class of epoxide hydrolases

BACKGROUND

Epoxide hydrolases have important roles in the defense of cells against potentially harmful epoxides. Conversion of epoxides into less toxic and more easily excreted diols is a universally successful strategy. A number of microorganisms employ the same chemistry to process epoxides for use as carbon sources.

RESULTS

The X-ray structure of the epoxide hydrolase from Aspergillus niger was determined at 3.5 A resolution using the multiwavelength anomalous dispersion (MAD) method, and then refined at 1.8 A resolution. There is a dimer consisting of two 44 kDa subunits in the asymmetric unit. Each subunit consists of an alpha/beta hydrolase fold, and a primarily helical lid over the active site. The dimer interface includes lid-lid interactions as well as contributions from an N-terminal meander. The active site contains a classical catalytic triad, and two tyrosines and a glutamic acid residue that are likely to assist in catalysis.

CONCLUSIONS

The Aspergillus enzyme provides the first structure of an epoxide hydrolase with strong relationships to the most important enzyme of human epoxide metabolism, the microsomal epoxide hydrolase. Differences in active-site residues, especially in components that assist in epoxide ring opening and hydrolysis of the enzyme-substrate intermediate, might explain why the fungal enzyme attains the greater speeds necessary for an effective metabolic enzyme. The N-terminal domain that is characteristic of microsomal epoxide hydrolases corresponds to a meander that is critical for dimer formation in the Aspergillus enzyme.

Statistical theory of combinatorial libraries of folding proteins: energetic discrimination of a target structure

A self-consistent theory is presented that can be used to estimate the number and composition of sequences satisfying a predetermined set of constraints. The theory is formulated so as to examine the features of sequences having a particular value of Delta=E(f)-<E>(u), where E(f) is the energy of sequences when in a target structure and <E>(u) is an average energy of non-target structures. The theory yields the probabilities w(i)(alpha) that each position i in the sequence is occupied by a particular monomer type alpha. The theory is applied to a simple lattice model of proteins. Excellent agreement is observed between the theory and the results of exact enumerations. The theory provides a quantitative framework for the design and interpretation of combinatorial experiments involving proteins, where a library of amino acid sequences is searched for sequences that fold to a desired structure.

The pyruvate dehydrogenase E1 alpha gene is testosterone and prolactin regulated in prostate epithelial cells

The prostate gland of humans and other animals has the unique function of accumulating and secreting extraordinarily high levels of citrate. The prostate secretory epithelial cells synthesize citrate which, due to a limiting mitochondrial (m-) aconitase, accumulates rather than being oxidized. Thus citrate is essentially an end product of metabolism in prostate. For continued net citrate production, a continual source of oxaloacetate (OAA) and acetyl CoA is required. Glucose via pyruvate oxidation provides the source of Acetyl CoA. In prostate cells, citrate production is regulated by testosterone and/or by prolactin. Both hormones selectively regulate the level and activity of pyruvate dehydrogenase E1 alpha (E1a) in animal prostate cells; thereby regulating the availability of acetyl CoA for citrate synthesis. Studies were conducted to determine if testosterone and prolactin might regulate the expression of the E1a gene in prostate epithelial cells. Prolactin treatment of rat ventral and lateral prostate cells and human PC3 cells increased the levels of E1a mRNA and the rates of transcription of the E1a gene. Testosterone also increased the mRNA level and transcription of E1a in rat ventral prostate cells, and in PC3 cells transfected with androgen receptor. However, testosterone treatment resulted in a repression of E1a gene expression in lateral prostate cells. Evidence is presented which supports the view that prolactin regulation of E1a is mediated via PKC. The rapidity of the effects of both hormones is representative of an immediate-early gene response. To our knowledge this represents the first report in any mammalian cells that, in addition to its constitutive expression in all mammalian cells, the E1a gene is a hormonally-regulated gene in specifically targeted prostate epithelial cells.

Effects of resveratrol on oxidative modification of human low density lipoprotein

OBJECTIVE

To determine the antioxidative effects of resveratrol (RES), a polyphenolic compound in red wine, on the oxidation of human low density lipoprotein (LDL) using two different oxidation systems.

METHODS

Oxidation of LDL was induced by adding either Cu2+ or an azo compound. The extent of LDL modification was assessed by measuring the formation of thiobarbituric acid reactive substances (TBARS), the relative electrophoretic mobilities (REM), and the amount of oxidized LDL degradation by macrophages.

RESULTS

During Cu(2+)-induced oxidation, RES reduced TBARS formation in LDL by 70.5%, REM of LDL by 42.3% and the amount of macrophage degradation by 65.7%, respectively. The lag phase of LDL oxidation was also delayed by adding RES both in the copper ion and azo compound-induced oxidation systems.

CONCLUSION

RES can protect LDL against both Cu(2+)-induced and azo compound-initiated oxidative modification in vitro, which might be due to its free radical scavenging capacity.

Transgenic mice overexpressing protein kinase C epsilon in their epidermis exhibit reduced papilloma burden but enhanced carcinoma formation after tumor promotion

To determine the role that protein kinase C epsilon (PKCepsilon) may play in skin growth, differentiation, and tumor promotion, transgenic mice were generated that overexpressed an epitope-tagged protein kinase C epsilon (T7-PKCepsilon) in their epidermis using the human keratin 14 promoter. Three independent mouse lines that overexpressed the T7-PKCepsilon in their epidermis were produced. The three independent lines 206, 224, and 215 exhibited a 3-, 6-, and 18-fold elevation, respectively, in the level of PKCepsilon immunoreactive protein. Line 215 exhibited a 19-fold greater phosphatidylserine and 12-O-tetradecanoylphorbol-13-acetate (TPA) stimulated kinase activity than line 224. Line 206 exhibited a low basal T7-PKCepsilon activity, which failed to be stimulated by phosphatidylserine and TPA. All of the line 215 transgenic mice (F0 to the F2 generation) displayed phenotypic changes in the skin. The phenotypic changes progressed gradually, starting around 4-5 months of age, with mild dryness of the tail accompanied by hair loss and inflammation at the base of the tail. Hyperproliferation and ulceration of the affected regions were observed around 7-8 months of age. The hyperproliferative epidermis from the affected regions exhibited an expansion of the suprabasal epidermal cells. Inflammation and/or ulceration were also observed in the dorsal skin, the ears, and around the eyes. The line 215 mice, which expressed the highest level of PKCepsilon, were evaluated for sensitivity to mouse skin tumor promotion by TPA. Tumors were elicited by the initiation (7,12-dimethylbenz[a]anthracene, 100 nmol)-promotion (TPA, 5 nmol/twice weekly) protocol. The papilloma burden was reduced by 95-96% for male and female T7-PKCepsilon mice compared to wild-type controls. However, carcinomas developed rapidly in the T7-PKCepsilon mice treated with 7, 12-dimethylbenz[a]anthracene and TPA. These carcinomas appeared to form independently of prior papilloma development. These results demonstrate that PKCepsilon is an important regulator of skin tumor development.

Zinc induces mitochondria apoptogenesis in prostate cells

BACKGROUND AND PURPOSE

Prostate secretory epithelial cells have the unique function and capability of accumulating extremely high intracellular levels of zinc. One of the effects of this accumulation is inhibition of cell growth due, in part, to an increase in apoptosis. The present studies were conducted to determine if this zinc-induced apoptosis involves stimulation of mitochondrial apoptogenesis.

MATERIALS AND METHODS

The PC-3 a human malignant prostate cell line, which is zinc accumulating, was exposed to medium supplemented with physiologic levels of zinc.

RESULTS

By 24 h, zinc treatment resulted in the translocation of cytochrome c from the mitochondria to the cytosol, the activation of caspase-9 and caspase-3, and eventually, the cleavage of nuclear poly(ADP)-ribose polymerase (PARP). Under similar conditions, exposure of freshly prepared rat ventral prostate cells (which are also zinc accumulating) resulted in increased apoptosis following translocation of cyochrome c and activation of caspases-9 and 3. The human prostate PZ-HPV-7 cells, which do not accumulate zinc, did not exhibit any apoptotic effect from zinc treatment.

CONCLUSION

The accumulation of high intracellular levels of zinc by prostate cells induces mitochondrial apoptogenesis. This represents a newly identified physiological effect of zinc in the regulation of prostate cell growth.

Effects of antisense repression of an Arabidopsis thaliana pyruvate dehydrogenase kinase cDNA on plant development

Pyruvate dehydrogenase kinase (PDHK), a negative regulator of the mitochondrial pyruvate dehydrogenase (PDH) complex (mtPDC), plays a pivotal role in controlling mtPDC activity, and hence, the TCA cycle and cell respiration. This report describes the cloning of a pyruvate dehydrogenase kinase cDNA (AtPDHK) from Arabidopsis thaliana and focuses on the effects of antisense down-regulation of its expression on plant growth and development. The deduced amino acid sequence of AtPDHK exhibits extensive similarity to other plant and mammalian PDHKs, containing conserved domains typical of two-component histidine protein kinases. The Escherichia coli expressed AtPDHK specifically phosphorylated mammalian PDH E1 in a time-dependent manner. Antisense expression of the AtPDHK cDNA led to marked elevation of mtPDC activity in transgenic plants with increases ranging from 137% to 330% compared to control plants. Immunoblot analyses performed with a monoclonal antibody to the E1alpha mtPDH component (the subunit phosphorylated by PDHK) indicated that the increased mtPDC activity was not the result of an increase in the level of PDH protein. MtPDC from transgenic plants showed a reduced sensitivity to ATP-dependent inactivation compared to that observed in wild-type plants. Collectively, these data suggest that the antisense partial silencing of the negative regulator, PDHK, was responsible for the increased mtPDC activity observed in the antisense PDHK plants. Transgenic plants with partially repressed AtPDHK also displayed altered vegetative growth with reduced accumulation of vegetative tissues, early flower development and shorter generation time. The potential role for AtPDHK gene manipulation in crop improvement is discussed.

Transgenic mice overexpressing protein kinase Cdelta in the epidermis are resistant to skin tumor promotion by 12-O-tetradecanoylphorbol-13-acetate

To determine the role of protein kinase Cdelta in mouse skin carcinogenesis, we have developed transgenic FVB/N mouse lines expressing in the epidermis an epitope-tagged protein kinase Cdelta (T7-PKCdelta) regulated by the human keratin 14 promoter. The untreated T7-PKCdelta mice displayed excessive dryness in the skin of the tail with a variable penetrance over time. Histologically, the tail skin showed hyperplasia with evidence of hyperkeratosis. The epidermis of the rest of the T7-PKCdelta mouse was unremarkable. Despite this mild phenotype, the effects of PKCdelta overexpression on mouse skin tumor promotion by 12-O-tetradecanoylphorbol-13-acetate (TPA) were dramatic. Two independent lines of T7-PKCdelta mice (16 and 37) expressing the T7-PKCdelta transgene were examined for responsiveness to skin tumor promotion by 7,12-dimethylbenz[a]anthracene and TPA. By immunoblot analysis, the T7-PKCdelta-16 and T7-PKCdelta-37 mice showed an 8- and 2-fold increase of PKCdelta protein. The T7-PKCdelta-16 mice averaged 300% more T7-PKCdelta activity than the T7-PKCdelta-37 mice did. The T7-PKCdelta-37 mice did not manifest any difference in tumor burden or incidence. However, the reduction in papilloma burden at 25 weeks of promotion for the T7-PKCdelta-16 mice relative to wild-type mice averaged 72 and 74% for males and females, respectively. The T7-PKCdelta-16 mice reached 50% papilloma incidence between 12 and 13 weeks of promotion compared with 8 weeks for wild-type mice. Furthermore, the carcinoma incidence was also reduced in T7-PKCdelta-16 mice. Carcinoma incidence at 25 weeks of promotion treatment was: wild-type females, 78%; T7-PKCdelta16 females, 37%; wild-type males, 45%; and T7- PKCdelta-16 males, 7%. Thus, PKCdelta when expressed at sufficient levels can suppress skin tumor promotion by TPA.

Suppression of mitogenesis and regulation of cell cycle traverse by resveratrol in cultured smooth muscle cells

Resveratrol (3,5,4'-trihydroxystilbene), a natural product derived from grapes, has been reported to exert a plethora of biological functions. Recent studies suggest that resveratrol could act as a cardioprotective agent by controlling the oxidation of low density lipoproteins, as well as the proliferation of endothelial cells. Since migration and proliferation of smooth muscle cells (SMCs) in the intima of susceptible vessels is also widely accepted as a requisite for atherogenesis, we investigated the effects of resveratrol on proliferation and cell cycle control of cultured smooth muscle cells. Results of these experiments are reported herein. Resveratrol reduces SMC proliferation in a dose-dependent manner, with 50-100 microM resveratrol resulting in 70-90% reduction of SMC proliferation induced by such diverse mitogens as serum, endothelin and PDGF. The anti-mitogenic effects of resveratrol are not mediated by the induction of apoptosis, but appear to relate to a G1-->S block in cell cycle traverse. These results give further support to the hypothesis that resveratrol holds promise as an anti-atherosclerotic agent.

The Arabidopsis thaliana TAG1 mutant has a mutation in a diacylglycerol acyltransferase gene

In Arabidopsis thaliana (ecotype Columbia) mutant line AS11, an EMS-induced mutation at a locus on chromosome II results in a reduced diacylglycerol acyltransferase (DGAT; EC 2.3.1.20) activity, reduced seed triacylglycerol, an altered seed fatty acid composition, and delayed seed development. A mutation has been identified in AS11 in a gene, which we designated as TAG1, that encodes a protein with an amino acid sequence which is similar to a recently reported mammalian DGAT, and, to a lesser extent, to acyl CoA:cholesterol acyltransferases. Molecular analysis revealed that the mutant allele in AS11 has a 147 bp insertion located at the central region of intron 2. At the RNA level, an 81 bp insertion composed entirely of an exon 2 repeat was found in the transcript. While the seed triacylglycerol content is reduced by the lesion in AS11, there is no apparent effect on sterol ester content in the mutant seed. The TAG1 cDNA was over-expressed in yeast, and its activity as a microsomal DGAT confirmed. Therefore, the TAG1 locus encodes a diacylglycerol acyltransferase, and the insertion mutation in the TAG1 gene in mutant AS11 results in its altered lipid phenotype.

Molecular cloning of interleukin 1beta from rainbow trout Oncorhynchus mykiss reveals no evidence of an ice cut site

The complete coding sequence of rainbow trout IL-1beta has been obtained. The gene contains a short 5' UTR (97 bp), a 780 bp open reading frame and a 466 bp 3' UTR, which includes a polyadenylation signal, 7 ATTTA motifs and an 18 bp poly A tail. The predicted amino acid sequence (260 amino acids) contains 3 potential glycosylation sites, with a predicted molecular weight of 29 kDa, and shows between 49 and 56% amino acid similarity to mammalian IL-1betas and 57% similarity to carp IL-1beta. Greatest homology was apparent within the secondary structure of the gene, with few of the amino acids known to bind to the IL-1 receptor being conserved. No ICE cut site was apparent but multiple alignment with mammalian sequences allowed a putative mature peptide of 166 amino acids to be identified, in which Ala(95)would be the amino terminus. Northern blot analysis showed that whilst no IL-1beta expression was detectable in head kidney leukocytes immediately after isolation, expression could be induced by stimulation with LPS for 4 h in culture. Similarly, with isolated head kidney macrophages expression was significantly increased following stimulation with LPS.

Seroprevalence of markers for hepatitis B, C and G in male and female prisoners--NSW, 1996

OBJECTIVES

1. Establish the prevalence of markers for hepatitis B (HBV), C (HCV) and G (HGV) in a sample of male and female inmates. 2. Examine exposure to multiple viruses. 3. Compare risk factors for HGV infection with known risk factors for HBV and HCV.

DESIGN

Cross-sectional random sample stratified by sex, age and Aboriginality. Inmates were screened for three hepatitis markers. Participants were 789 inmates (657 male, 132 female) in 27 correctional centres in New South Wales, 1996.

RESULTS

Overall detection of each of the three screening markers was 35% for HBV, 39% for HCV and 10% for HGV. Exposure rates were higher in female prisoners than males. Increased rates of anti-HBc were observed in Aboriginal inmates compared with non-Aboriginals (54% cf. 27%); anti-HCV and HGV-RNA were comparable between the two groups (36% cf. 41% and 9% cf. 10%). Markers were significantly higher in female injecting drug users (IDU), particularly HCV (90% cf. 66%). Thirty-five per cent of inmates were unaware of their HCV status. For HBV, 72% did not self-report past or present exposure despite serological evidence to the contrary. The multivariate analysis identified Aboriginality, long-term injecting and injecting while in prison as risk factors for HBV. HCV risk factors were female sex, non-Aboriginality, institutionalisation and IDU-associated behaviours. For HGV, female sex and previous imprisonment were significant risk factors but IDU was not.

CONCLUSIONS

Blood-borne hepatitis viruses are common in prison inmates, particularly females (HBV, HCV and HGV), Aboriginals (HBV) and IDU (HBV and HCV). Infection can be related to a number of risk factors, which appear similar for HBV and HCV, but distinct from HGV.

Evaluation of disinfection and sterilization of reusable angioscopes with the duck hepatitis B model

PURPOSE

Nosocomial transmission of viral hepatitis and retrovirus infection has been reported. The expected risk is greatest for the hepatitis B virus (HBV). The duck HBV (DHBV) has similar biologic and structural characteristics to HBV and has been adopted as a suitable model for disinfectant testing.

METHODS

Angioscopic examination of the external jugular vein was performed on DHBV-infected ducks. After use, the instrument was air dried for 3 minutes. Samples were obtained by flushing the channel with 5 mL of phosphate buffered saline solution. The samples were collected immediately after drying (control), after flushing with 5 mL of water, after glutaraldehyde disinfection for 5, 10, and 20 minutes, and after ethylene oxide gas sterilization. Angioscopes were either precleaned or uncleaned before disinfection/sterilization. Residual infectivity was assessed with inoculation of samples into the peritoneal cavity of day-old ducks (n = 231).

RESULTS

DNA analysis results of liver samples showed that all 38 control ducks became infected. The frequency of DHBV infection was reduced to 93% (14 of 15) by flushing the angioscope with 5 mL of sterile water. No transmission occurred after the use of any of the properly precleaned and disinfected/sterilized angioscopes. However, after the use of the uncleaned angioscopes, the transmission rate was 90% (9 of 10) and 70% (7 of 10) after 5 and 10 minutes of contact time, respectively, in 2% glutaraldehyde. Even after the recommended 20 minutes of contact time, there was still 6% (2 of 35) transmission. After ethylene oxide sterilization, two of the recipient ducklings (2 of 35) were infected with DHBV.

CONCLUSION

There was no disease transmission after reuse of disposable angioscopes adequately cleaned before disinfection or sterilization. However, if the angioscopes are inadequately cleaned, DHBV can survive despite glutaraldehyde disinfection or ethylene oxide sterilization. This contrasts with previous in vitro and in vivo data with solid surgical instruments. It is postulated that the presence of a narrow lumen or residual protein shielding within the lumen may compromise effective inactivation of hepadnaviruses on angioscopes, with the potential risk for patient-to-patient transmission.

Evidence for a zinc uptake transporter in human prostate cancer cells which is regulated by prolactin and testosterone

The glandular epithelial cells of the human prostate gland have the unique capability and function of accumulating the highest zinc levels of any soft tissue in the body. Zinc accumulation in the prostate is regulated by prolactin and testosterone; however, little information is available concerning the mechanisms associated with zinc accumulation and its regulation in prostate epithelial cells. In the present studies the uptake and accumulation of zinc were determined in the human malignant prostate cell lines LNCaP and PC-3. The results demonstrate that LNCaP cells and PC-3 cells possess the unique capability of accumulating high levels of zinc. Zinc accumulation in both cell types is stimulated by physiological concentrations of prolactin and testosterone. The studies reveal that these cells contain a rapid zinc uptake process indicative of a plasma membrane zinc transporter. Initial kinetic studies demonstrate that the rapid uptake of zinc is effective under physiological conditions that reflect the total and mobile zinc levels in circulation. Correspondingly, genetic studies demonstrate the expression of a ZIP family zinc uptake transporter in both LNCaP and PC-3 cells. The rapid zinc uptake transport process is stimulated by treatment of cells with physiological levels of prolactin and testosterone, which possibly is the result of the regulation of the ZIP-type zinc transporter gene. These zinc-accumulating characteristics are specific for prostate cells. The studies support the concept that these prostate cells express a unique hormone-responsive, plasma membrane-associated, rapid zinc uptake transporter gene associated with their unique ability to accumulate high zinc levels.

Fish macrophages express a cyclo-oxygenase-2 homologue after activation

In mammals, the increased generation of prostaglandins (PG) during the onset of inflammatory responses and activation of immune cell types has been attributed to the induction of a novel cyclo-oxygenase (COX) isoform, termed COX-2, which is distinct from the well-characterized constitutive activity (COX-1). Goldfish (Carassius auratus) macrophages exposed to bacterial lipopolysaccharide and leucocyte-derived macrophage-activating factor(s) showed a significant increase in the generation of the major COX product, PGE2, within the first 6 h of stimulation. The selective COX-2 inhibitor, NS398, inhibited this elevated generation of PGE, whereas the basal level of this product synthesized by unstimulated macrophages was unaffected by such exposure. PGE generation by goldfish macrophages was similarly inhibited by the glucocorticoid, dexamethasone, and an inhibitor of protein synthesis, cycloheximide, suggesting that this stimulation may be due to an inducible enzyme equivalent to mammalian COX-2. The complete coding sequence of rainbow trout (Oncorhynchus mykiss) COX-2 was obtained by PCR. The gene contains a 61 bp 5'-untranslated region (UTR), a 1821 bp open reading frame and a 771 bp 3'UTR containing multiple copies of an mRNA instability motif (ATTTA). The predicted translation product had high homology to known mammalian and chicken COX-2 (83-84%) and COX-1 (77%) sequences. Reverse-transcriptase PCR with cDNA from control and bacterially challenged fish revealed that trout COX-2 expression was not constitutive but could be induced. Overall, these studies show for the first time that the inducible isoform of COX has a long evolutionary history, probably dating back to the evolution of fish over 500 million years ago.

Cloning of two chemokine receptor homologs (CXC-R4 and CC-R7) in rainbow trout Oncorhynchus mykiss

Two rainbow trout chemokine receptors have been sequenced, with homology to CXC-R4 and CC-R7 molecules. The CXC-R4 sequence consisted of 1681 nucleotides, which translated into a mature protein of 357 amino acids, with 80.7% similarity to human CXC-R4. The CC-R7 sequence consisted of 2287 nucleotides, which translated into a 368-amino acid mature protein with 64.5% similarity to human CC-R7. Both sequences contained seven hydrophobic regions, representing the seven transmembrane domains (TM) typical of G-protein-coupled receptors. Extracellular cysteines, transmembrane prolines, and the DRY motif immediately following TM3 were conserved. Phylogenetic tree analysis revealed a tight clustering of trout CXC-R4 with CXC-R3-5 genes. Trout CC-R7 clustered with CC-R6-7 and CXC-R1-2. Reverse transcriptase-polymerase chain reaction analysis demonstrated a wide tissue distribution of CXC-R4 and CC-R7 message in trout, being present in head-kidney leukocytes, blood, gill, brain, spleen, and liver.

Inactivation of duck hepatitis B virus by a hydrogen peroxide gas plasma sterilization system: laboratory and 'in use' testing

Human hepatitis B virus (HBV) is an important cause of nosocomial infections and can be transmitted by contaminated instruments. However, tests of the efficacy of sterilization of materials and equipment contaminated by HBV are difficult to perform because the virus cannot be cultured in the laboratory. In this study, we aimed to evaluate the capability of a low temperature, hydrogen peroxide gas plasma sterilizer (Sterrad, Advanced Sterilization Products, Irvine California,) to inactivate duck hepatitis B virus (DHBV). In laboratory efficacy studies using DHBV dried on to glass filter carriers and exposed to one-half of the hydrogen peroxide gas plasma sterilization process, there was a 10(7) or greater decrease in the viral titer, with no infectivity detected on the carriers after treatment. In-use studies were performed using a laparoscope that was experimentally contaminated with DHBV to mimic the possible transmission of infection between successive patients. Following exposure to the hydrogen peroxide gas plasma sterilization process no transmission of DHBV infection from the laparoscope occurred despite obvious visual soiling with blood (N = 8) while the transmission rate for the unprocessed laparoscope (positive control) was 100% (26/26), and that for instruments after a water wash was 63% (7/11). In conclusion the hydrogen gas plasma sterilization process completely inactivates DHBV a representative of the hepadna group of viruses.

The rainbow trout Oncorhynchus mykiss interleukin-1 beta gene has a differ organization to mammals and undergoes incomplete splicing

The rainbow trout interleukin (IL)-1 beta gene consists of six exons/five introns, in contrast to mammals which have seven exons/six introns. The missing exon appears to be at the 5' end of the gene, probably equivalent to exon 1 or 2 of mammals. Fewer and smaller introns make the trout IL-1 beta only half the size of mammalian IL-1 beta genes. Highest homology (> 60% amino acid similarity) is seen between exon 5 of trout and exon 6 of mammals. Reverse transcription-PCR analysis revealed two additional incompletely spliced variants of the trout IL-1 beta gene, containing intron 5 or introns 4 and 5. All three transcripts are detectable in gill, kidney, liver and spleen tissue from bacterially challenged fish but only the fully spliced transcript is detectable in blood. Northern blot analysis revealed that the latter transcript is also induced following stimulation of kidney leucocytes with lipopolysaccharide for 4 h. A second inducible transcript is also detected but is larger (approximately 3 kb) than any of the above, suggesting that it could be from a second gene. Southern blot analysis also suggests at least two copies of the IL-1 beta gene or genes related to the 3' end of the IL-1 beta sequence, are present in trout.

Rainbow trout cytokine and cytokine receptor genes

Transforming growth factor-beta (TGF-beta) and interleukin-1 beta (IL-1 beta) have been cloned from rainbow trout (Oncorhynchus mykiss) in our laboratory. The trout TGF-beta is typical of members of the cysteine knot cytokine family, and has highest homology to TGF-beta 1, TGF-beta 4 and TGF-beta 5. The gene organisation is different to other TGF-beta genes despite the presence of seven exons. Trout IL-1 beta has less homology to known IL-1 beta s (49-56% amino acid similarity) but shows clear conservation of the secondary structure of the "mature peptide". An interleukin-converting enzyme cut site is not apparent however, and it remains to be determined whether fish IL-1 beta must be cleaved for biological activity. The trout IL-1 beta gene consists of six exons, one less than in mammals, with the missing exon at the 5' end of the gene. Two trout chemokine receptors have also been isolated in our laboratory, having high homology to CXC-R4 and CC-R7 (67% and 56% nucleotide identity respectively). With a view to studying the biological effects of fish cytokines we have also cloned the inducible nitric oxide (iNOS) and cyclooxygenase (COX-2) genes in trout. Both have high homology to known mammalian and chicken genes, and have been shown to be inducible in trout.

[Heat shock response in experimental acute middle ear bacterial infection]

OBJECTIVE

To investigate the association between bacteria antigen and inner ear antigen and effects of stress on the expression spectrum and level of the antigen bearing hsp70 related epitope.

METHODS

Use monoclonal antibody against mammiferous hsp70 to recognize the related antigens of Bacillus pyocyaneus, Bacillus proteus, Bacillus coli, Staphylococcus aureus and Klebsiella pneumoniae with modified western blotting. The expression level of hsp70 in unstressed guinea pig inner ear was tested. An animal model of middle ear acute infection by Klebsiella pneumoniae was established. The dynamic changes of mammiferous hsp70 epitope related proteins were tested with modified western blotting.

RESULTS

All the bacteria antigens recognized by anti-mammiferous hsp70 antibody were not of the hsp70 family and the expression level of hsp70 in normal guinea pig was extraordinarily low. Klebsiella pneumoniae expressed 70,000 dalton and 17,000 dalton hsp after its invasion into guinea pig middle ear. 70,000 dalton antigen expressed most intensely at 3rd day of invasion and then fell. 17,000 dalton antigen was expressed most intensely at 5th day of invasion and then fell. The expression of 70,000 dalton hsp was much weaker than 31,000 dalton hsp at acute periods of middle ear infection.

CONCLUSIONS

The elevated expression of hsp both in bacteria and inner ear during middle ear acute infection provides material base for immune impairment on inner ear induced by bacterial infection. The low molecular weight hsp may be involved in the inner ear autoimmune impairment.

Repression of heat shock transcription factor HSF1 activation by HSP90 (HSP90 complex) that forms a stress-sensitive complex with HSF1

Heat shock and other proteotoxic stresses cause accumulation of nonnative proteins that trigger activation of heat shock protein (Hsp) genes. A chaperone/Hsp functioning as repressor of heat shock transcription factor (HSF) could make activation of hsp genes dependent on protein unfolding. In a novel in vitro system, in which human HSF1 can be activated by nonnative protein, heat, and geldanamycin, addition of Hsp90 inhibits activation. Reduction of the level of Hsp90 but not of Hsp/c70, Hop, Hip, p23, CyP40, or Hsp40 dramatically activates HSF1. In vivo, geldanamycin activates HSF1 under conditions in which it is an Hsp90-specific reagent. Hsp90-containing HSF1 complex is present in the unstressed cell and dissociates during stress. We conclude that Hsp90, by itself and/or associated with multichaperone complexes, is a major repressor of HSF1.

Relationship between cellular uptake rate and chemical behavior of diammine/diaminocyclohexane platinum (II) complexes with oxygen-ligating anionic groups

The uptake kinetics of the platinum (II) complexes of the formula Pt(NH3)2X, Pt(dach)X by human erythrocyte in the plasma isotonic buffer was studied. The results showed that across-membrane transport of all the platinum complexes studied follows a first-order kinetic process. The uptake rate constants decrease with the change of oxygen-ligating anionic group in the sequence: sulfato > selenato > anion of squaric acid > oxalato > anion of demethylcantharic acid > malonato and increase with increasing lipophilicity of carrier group. The relationship between uptake rate and reactivity of these complexes was established. The stereochemistry of dach isomers was shown without effect on the reactivity and the sequence.

Correlation between glutathione oxidation and trimerization of heat shock factor 1, an early step in stress induction of the Hsp response

The heat shock protein (Hsp) response is induced by heat shock and a large variety of different chemicals. Searching for a common denominator of these different inducers, we and others developed the notion that all inducers may generate abnormally folded, i.e. non-native, proteins, and that such non-native proteins may trigger the Hsp response. Experimentation prompted by this notion resulted, for example, in the demonstration that chemically denatured proteins, introduced in cells by microinjection, can activate the response. Based on the chemical nature of inducers and on results reported from several studies, we hypothesized that inducers of the Hsp response may be generally capable of triggering oxidation of non-protein thiols, particularly glutathione. Such oxidation is known to lead to formation of glutathione-protein mixed disulfides and protein-protein disulfides. Presumably, thiol adduction and cross-linking would affect the structure of proteins involved, resulting in unfolding of a fraction of these proteins, causing heat shock factor (Hsf) activation. To test the feasibility of this hypothesis, thirteen different inducers were selected, and it was shown that all chemical inducers as well as heat shock cause drastic oxidation of glutathione under conditions under which they induce HSE DNA-binding activity. Under the same conditions, all chemical inducers and heat shock also cause trimerization of Hsf1. For several inducers, it was also shown that they enhance thiol oxidation of proteins. Finally, in vitro experiments support the notion that activation of Hsf1 does not require oxidation of the factor itself or of its coregulators. These results are in complete agreement with the above hypothesis.

Detection of persistent vegetative bacteria and amplified viral nucleic acid from in-use testing of gastrointestinal endoscopes

Hospital-acquired infection attributed to inadequate decontamination of gastrointestinal endoscopes prompted an in use evaluation of recommended procedures. Specimens were obtained from the internal channels of 123 endoscopes before, during and after decontamination by flushing with saline and brushing with a sterile brush, and examined for vegetative bacteria by broth and plate culture. Four endoscopy units were tested; the chemical disinfectants used were: 2% glutaraldehyde in Centres 1 and 2 (automated) and Centre 3 (manual); peracetic acid in Centre 4 (automated). Samples from patients in Centre 1 with known chronic hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV-1) infection were also examined for viral nucleic acid by ultracentrifugation, nucleic acid extraction, reverse transcription (for RNA) and polymerase chain reaction (PCR). No persistent vegetative bacteria were found following standard manual cleaning and disinfection for 20 min in 2% glutaraldehyde in Centres 2 and 3 (N = 37). At Centre 1, while plate culture yielded no growth, 34% of samples (10/29) grew vegetative bacteria in broth culture after cleaning and disinfection for 20 min in 2% glutaraldehyde. Investigation revealed an error in manual cleaning; no bacteria were detected in 37 samples taken after this was corrected. At Centre 4, despite the use of peracetic acid as a sterilant, three out of 20 (15%) of post decontamination samples grew bacteria; one contained persistent bacteria. HBV and HCV PCR analysis detected viral nucleic acid in three out of four and four out of six samples from viraemic patients undergoing endoscopy in Centre 1 during the period of improper manual washing. After proper cleaning was instituted, samples from nine out of nine HCV viraemic patients were negative. HIV RNA was detected in five of 14 samples taken from endoscopes after use on HIV positive patients but all post decontamination samples were negative. Detection of bacteria in washes from endoscope channels is a useful warning of a breakdown in decontamination practice. Inadequate brushing of internal channels may result in persistent HCV and HBV viral nucleic acid, the significance of which is not clear. These results reinforce the importance of adequate manual cleaning of endoscopes before chemical disinfection.

[Effects of different dilution of specific antibodies against the cell surface protein P1 of S. mutans MT 6R upon its adherence]

The sera and saliva were obtained from BALB/C mice by injection of the cell surface protein P1 and Freud's adjuvant. High antibody titers were showed in the sera and saliva by an enzyme-linked immunosorbent assay. Different dilution of the specific antibodies against the protein P1 of S. mutans had different inhibition effects on adhering of S. mutans MT 6R. Adherence of streptococcus mutans MT 6R on saliva-coated hydroxyapatite was reduced significantly by using sera and salivary antibodies in dilution of 1:1, 1:2, 1:4, 1:8, 1:16, 1:32 (P < 0.05).

[Effects of specific antibodies against the cell surface protein P1 of streptococcus mutans MT 6R upon adhered streptococci]

The sera and saliva were obtained from BALB/C mice by injection of the cell surface protein P1 and Freud's adjuvant. High antibody titers were showed in the sera and saliva by an enzyme-linked immunosorbent assay. The cells of S. mutans (serotype c, e and f) adhered on saliva-coated hydroxyapatite could be detached by the antibodies of the protein P1 of S. mutans MT 6R including in the sera and saliva (P < 0.05), but the antibodies had no influence on the cells of S. cricetus AHT, S. sobrinus OMZ176, S. sobrinus 6715 and S. rattus BHT (P > 0.05).

Cloning and molecular characterization of an Arabidopsis thaliana RING zinc finger gene expressed preferentially during seed development

The RING (Really Interesting New Gene) finger is a zinc-binding domain that is found in proteins from a variety of species. This paper reports the cloning and characterization of, as yet, only the second RING finger protein gene from plants, A-RZE, in Arabidopsis thaliana. In addition to the RING-finger motif, A-RZF also contains a putative nuclear localization signal. A-RZF is encoded by a single copy gene with an intron of 595 bp interrupting the 5' leader sequence and the coding region. Northern blot analysis indicated that A-RZF is expressed preferentially during seed development. The RING-finger motif, putative nuclear localization signal, and unique expression pattern, predict an important role during seed development for A-RZF.

Modification of seed oil content and acyl composition in the brassicaceae by expression of a yeast sn-2 acyltransferase gene

A putative yeast sn-2 acyltransferase gene (SLC1-1), reportedly a variant acyltransferase that suppresses a genetic defect in sphingolipid long-chain base biosynthesis, has been expressed in a yeast SLC deletion strain. The SLC1-1 gene product was shown in vitro to encode an sn-2 acyltransferase capable of acylating sn-1 oleoyl-lysophosphatidic acid, using a range of acyl-CoA thioesters, including 18:1-, 22:1-, and 24:0-CoAs. The SLC1-1 gene was introduced into Arabidopsis and a high erucic acid-containing Brassica napus cv Hero under the control of a constitutive (tandem cauliflower mosaic virus 35S) promoter. The resulting transgenic plants showed substantial increases of 8 to 48% in seed oil content (expressed on the basis of seed dry weight) and increases in both overall proportions and amounts of very-long-chain fatty acids in seed triacylglycerols (TAGs). Furthermore, the proportion of very-long-chain fatty acids found at the sn-2 position of TAGs was increased, and homogenates prepared from developing seeds of transformed plants exhibited elevated lysophosphatidic acid acyltransferase (EC 2.3.1.51) activity. Thus, the yeast sn-2 acyltransferase has been shown to encode a protein that can exhibit lysophosphatidic acid acyltransferase activity and that can be used to change total fatty acid content and composition as well as to alter the stereospecific acyl distribution of fatty acids in seed TAGs.

Prolactin regulation of mitochondrial aspartate aminotransferase and protein kinase C in human prostate cancer cells

Citrate production is a major physiological function of the prostate that is regulated by testosterone and prolactin. Mitochondrial aspartate aminotransferase (mAAT) is a key enzyme in the metabolic pathway of prostate citrate production. In addition, prolactin stimulates expression of mAAT in the rat lateral prostate. In this report we establish the role of prolactin in the regulation of mAAT in two prostate cancer cell lines, LNCaP and PC-3. LNCaP cells respond to hormonal stimulation with increased secretion of prostate specific products. PC-3 cells, on the other hand, are testosterone independent and apparently do not respond to other growth factors either. Results showed that both LNCaP and PC-3 cells responded to prolactin with increased mAAT activity and an increased steady state level of mAAT mRNA. Prolactin also increased protein kinase C (PKC) activity in both these cell lines. Treatment of LNCaP and PC-3 cells with the phorbol ester 12-O-tetradecanoylphorbol (TPA) caused the same effect on mAAT activity and mRNA level as prolactin. The results suggest that the diacylglycerol-PKC signal transduction system mediates the prolactin effect on mAAT. In addition, these results also show that the prolactin effect on mAAT is independent of androgens since PC-3 cells reportedly lack androgen receptor expression. Thus, these results provide evidence that prolactin is a physiological regulator of prostate function in human as well as rat prostate. In addition, the results also show that though prostate cancer cells are androgen independent, they remain responsive to prolactin. This could have important implications for the treatment and management of prostate cancer.

Differential associations between the cytoplasmic regions of the interleukin-12 receptor subunits beta1 and beta2 and JAK kinases

The role of the cytoplasmic regions of interleukin-12 receptors (IL-12R) beta1 and beta2 in stimulating proliferation was examined. The transmembrane and cytoplasmic regions of IL-12Rbeta1 or IL-12Rbeta2 were fused to the extracellular domain of the epidermal growth factor (EGF) receptor, yielding chimeric receptors E12R1 and E12R2, respectively. These chimeras were stably transfected into BaF3 cells, a factor-dependent murine pro-B cell line. Only E12R2 or E12R1+E12R2 transfectants were capable of EGF-dependent proliferation. EGF-dependent phosphorylation of E12R2, JAK2, Tyk2, and STAT3 was observed. JAK2 was phosphorylated in E12R1-, E12R2-, and E12R1+E12R2-expressing cells. However, direct associations were detectable only between E12R2 and JAK2. Tyk2 phosphorylation was observed only in cells expressing E12R1 or E12R1+E12R2. In parallel with this activation pattern, direct interactions only between Tyk2 and E12R1 were demonstrable. Phosphorylation of STAT3 was observed in cells expressing E12R1, E12R2, and E12R1+E12R2. The expression levels of STAT4 protein in BaF3 cells are undetectable by the methods employed here; therefore, STAT4 phosphorylation was not observed. Taken together, the data indicate that differential interactions take place between the cytoplasmic regions of the two IL-12R subunits and JAK2/Tyk2 and that the cytoplasmic region of IL-12Rbeta2 alone is capable of delivering a proliferative signal.

Synthesis, antitumor activity and acute toxicity of diammine/diamino-cyclohexane platinum(II) complexes with oxygen-ligating leaving group

In order to clarify the relation between the reactivity of the leaving groups in cisplatin-like complexes and their activity / toxicity, six new complexes of the formula Pt(NH3)2X and Pt(dach)X (where X is selenato, anion of squaric acid, or demethylcantharic acid) have been synthesized and compared. These complexes have been characterized by elemental analysis, infrared spectroscopy, and conductivity measurements. Six human neoplastic cell lines (HCT, KB, BGC, HL-60, K-563 and Bel-7402) were used to screen these compounds. The results demonstrated that four of them have comparable IC50 and even lower IC50 in a few kinds of tumor cell lines compared to cisplatin. Their LD50 values showed that the toxicity of these platinum complexes is related to the reactivity of the leaving groups. All of these complexes have lower acute toxicity than cisplatin, but the anticancer activity is not affected.

The chirality selectivity in the uptake of platinum (II) complexes with 1,2-cyclohexanediamine isomers as carrier ligand by human erythrocytes

The uptake kinetics of cisplatin analogs of 1,2-cyclohexanediamine(dach) isomers with various leaving groups, by human erythrocytes in plasma isotonic buffer, were studied. The experimental results showed that the uptake rate constants (k values) decrease with the change of leaving group in the sequence: chloride (Cl) > squaric acid (SA) > oxalate (OX) > demethylcantharic acid (DA), with the same dach isomer as carrier group. It is noteworthy that for the platinum (II) complexes with the same leaving group, the k values always reduce as: 1R, 2R-dach > 1R, 2S-dach > 1S, 2S-dach. This result reflects the chirality selectivity. No differences in reactivity to protein thiols and effects on membrane permeability were found for the R,R-, R,S-, S,S-isomeric complexes. It is proposed that the chirality selectivity in uptake is due to the recognition of the chirality of the platinum complexes by the erythrocyte membrane. The interactions between the chiral platinum complexes and the head groups of the membrane phospholipid molecules are probably involved.

Approaches and reconstruction in skull base operation

OBJECTIVE

To design convenient lateronasal and infrafrontal approaches or lateronasal subvolution approach to radically resect skull base tumors involving cranial cavity.

METHODS

From 1987 through 1994, 22 patients with malignant tumors, 6 with benign tumors, one with a giant sphenoid sinus cyst and one with intranasal meningoencephalocele underwent the operation. Twenty-three cases had anterocranial fossa involved; 4, midcranial fossa; 2, anteromedial cranial fossa; and 1 case, posteromedial cranial fossa. Among the patients with malignant tumors, 11 underwent expansive maxillectomy and 10 had orbital contents resected. The intracranial approaches through lateronasal and infrafront (21 cases), nasal columella lateral subvolution (3 cases) and other approaches were used.

RESULTS

The reconstruction of bony skull base defect in excess of 3.00 cm x 3.00 cm with total front musculocutaneous flap (8 cases), galeal and pericranial flap (5 cases) or other tissues (3 cases) has effectively prevented meningoencephalocele. Twelve cases had the dura resected in a range of 2.00 cm x 2.00 cm to 7.00 cm x 6.00 cm. Reconstruction of the dura defect with autofascia lata in 9 cases and other tissues in 3 cases effectively prevented the cerebrospinal fluid leak. Eight of 22 (36.4%) patients with malignant tumors have been alive and free of disease for 3-7 years after the operation. Six patients with benign tumors, one patient with giant sphenoid sinus cyst and one with meningoencephalocele were cured with this reconstructing method.

CONCLUSIONS

Frontal musculocutaneous and pericranial flaps have advantages over free bone because of easy surviving and easy operating without occurrence of osteonecrosis and exclusive reaction.

An observation on otoacoustic emission and ultrastructure of cochlea in experimental autoimmune inner ear disease

OBJECTIVE

To acquire the detailed knowledge of immune lesion of inner ear.

METHODS

A simultaneous study on physiology and ultrastructure was carried out in guinea pigs immunized with homogenous inner ear antigen. The specific antibody was analysed by a modified immunotransfer electrophoresis method.

RESULTS

Three positive bands (with molecular weights of 68.0 kD, 62.7 kD and 60.1 kD) were found in all the sera of immunized animals but not in the control animals. Threshold shift of auditory brainstem response over 10dB HL was found in 42% of secondary system immunized animals and 32% of secondary endolymphatic sac (e.sac) immunized animals. Amplitude of distortion production otoacoustic emission dropped obviously in the above two groups. Transmission electron microscope showed the mitochondria of outer hair cells in the cochlea was impaired in animals with auditory disorder.

CONCLUSIONS

The research suggests that the immune reaction against homogenous inner ear antigen results in dysfunction of hydroxycorticosteroid during the early stage.

Establishment of an in-use testing method for evaluating disinfection of surgical instruments using the duck hepatitis B model

Nosocomial transmission of hepatitis B virus (HBV), associated with interventional procedures, has been attributed to its survival on improperly decontaminated instruments. To date, guidelines for chemical disinfection of potentially contaminated heat-sensitive instruments have been based largely on extrapolation of data from in-vitro disinfectant testing. Direct infectivity testing has not been possible for HBV because of the lack of a practical culture assay or susceptible experimental animal model. In this study the related duck hepadnavirus was used to simulate in-vivo transmission of a HBV during surgery, and to evaluate the effectiveness of 2% glutaraldehyde disinfection of surgical laparoscopes. Multiple laparoscopic liver biopsies were performed on 'biohazardous' duck hepatitis B (DHBV) positive ducks. Laparoscopes were then subjected to different disinfection regimes using 2% glutaraldehyde, and residual infectivity tested by placing their tips into the peritoneal cavities of uninfected four-day-old ducklings. Direct transmission of DHBV occurred in all ducks when laparoscopes were not washed. Rinsing with water lowered the transmission rate to 64% and no infection transmission occurred after 5 min of contact time with the disinfectant. In contrast, previous in-vitro studies had shown complete viral inactivation after a shorter period of disinfection. It is postulated that the longer inactivation time observed in our study may be a result of surface interactions of virus and instrument, interfering with disinfectant access or activity. Tests of instrument surface samples for viral DNA by the polymerase chain reaction (PCR) did not correlate with transmission of virus infection in vivo. PCR is an inappropriate test for evaluating the efficacy of disinfectant action despite its sensitivity. This in use method will allow testing of other decontamination procedures and their effectiveness on more complex surgical instruments.

Cloning of a cDNA encoding the 21.2 kDa oleosin isoform from Arabidopsis thaliana and a study of its expression in a mutant defective in diacylglycerol acyltransferase activity

A full-length cDNA clone (pA23) of 832 bp encoding an oleosin from Arabidopsis thaliana was isolated by differential screening of a silique-specific cDNA library with probes prepared from poly(A)+ RNA isolated from developing seeds of wild-type (WT) Arabidopsis and from mutant AS11 with a lesion affecting diacylglycerol acyltransferase (DGAT) activity during embryo development. The encoded protein has a calculated molecular mass of 21.2 kDa, and its amino acid sequence shows strong sequence homology and structural similarity to other known oleosins. Transcription of the oleosin gene during seed development was both reduced and delayed in AS11 compared to WT. However, the level of oleosin protein did not appear to be down-regulated during seed development, and at maturity, the overall level of oleosin protein was similar in both WT and AS11. These findings indicate that regulation of oleosin gene expression is part of a highly complex, and co-ordinated expression of storage lipid biosynthesis and related (oleosin) genes during oilseed development.

Evidence for a role of Hsp70 in the regulation of the heat shock response in mammalian cells

Heat and other environmental insults (stress) cause unfolding of proteins, triggering the activation of heat shock transcription factor HSF (HSF1 in vertebrates) that, in higher eukaryotes, involves trimerization of the factor and acquisition of heat shock element (HSE) DNA-binding ability. Interaction of activated HSF1 with HSEs in promoters of genes encoding heat shock proteins (Hsps) enhances their expression. It was suggested that Hsp70 may function as the negative regulator of HSF1. In the simplest model, stress-unfolded proteins would compete with monomeric HSF1 for Hsp70 binding. This competition would result in dissociation of an HSF1-Hsp70 complex, allowing trimerization of released HSF1 monomers. In support of this model, we present evidence herein that 1) non-activated HSF1 forms a 1:1 complex with Hsp70, 2) both rates of heat-induced appearance of HSF1 oligomers and rates of disappearance of HSF1 heterodimers and monomers decrease when concentrations of unengaged Hsps are increased, and 3) transient overexpression of Hsp70 inhibits heat activation of HSF1.

Regulation of citrate metabolism by androgen in the LNCaP human prostate carcinoma cell line

Citrate production and accumulation are characteristic physiological functions of the prostate gland that are regulated by testosterone and prolactin. Results reported here show that treatment of LNCaP cells with dihydrotestosterone (DHT) resulted in increased intracellular citrate and increased citrate accumulation in the medium. Moreover, DHT also caused an increase in both mitochondrial aspartate aminotransferase (mAAT) activity and the steady state level of pmAAT (precursor) mRNA. Androgen treatment increased the rate of citrate oxidation by LNCaP cells as it does in rat ventral prostate which suggests that DHT increased aconitase activity in LNCaP cells. The results reported here are consistent with the operation of the glutamate-aspartate-citrate pathway that we described for rat ventral prostate. In addition, these results provide the first evidence that androgen responsive functions associated with citrate metabolism are retained in LNCaP cells. In addition, and more important, these results suggest that the more aggressive PC-3 carcinoma cell line has a higher rate of citrate oxidation than the less aggressive LNCaP cell line. This could have significant implications for our understanding of the relationship between alterations in prostate citrate metabolism and expression of the malignant phenotype.

Induction of Lipid and Oleosin Biosynthesis by (+)-Abscisic Acid and Its Metabolites in Microspore-Derived Embryos of Brassica napus L.cv Reston (Biological Responses in the Presence of 8[prime]-Hydroxyabscisic Acid)

Microspore-derived (MD) embryos of Brassica napus L. cv Reston were used to test the effects of (+)-abscisic acid ([(+)-ABA]) and its metabolites, 8[prime]-hydroxyabscisic acid (8[prime]-OH ABA) and (-)-phaseic acid (PA), on the accumulation of very long-chain monounsaturated fatty acids (VLCMFAs) and induction of genes encoding a 19-kD oleosin protein and a [delta]15 desaturase during embryogenesis. Developing early to mid-cotyledonary MD embryos at 16 to 19 d in culture were treated with 10 [mu]M hormone/metabolite for 4 d. At various times during incubation, embryos and medium were analyzed to determine levels of hormone/metabolite, VLCMFAs, and oleosin or [delta]15 desaturase transcripts. The VLCMFAs, 20:1 and 22:1, primarily in triacylglycerols, increased by 200% after 72 h in the presence of (+)-ABA and 8[prime]-OH ABA relative to the control. In contrast, treatment with PA for 72 h had little effect (20% increase) on the level of VLCMFAs. The first 24 to 72 h of (+)-ABA treatment were critical in the induction of VLCMFA biosynthesis, with 8[prime]-OH ABA lagging slightly behind (+)-ABA in promoting this response. The accumulation of VLCMFAs was positively correlated with an increase in elongase activity. (+)-ABA and its 8[prime]-OH ABA metabolite induced the accumulation of a 19-kD oleosin transcript within 2 to 4 h in culture. In addition, both (+)-ABA and 8[prime]-OH ABA induced the same level of [delta]15 desaturase transcript by 8 h. PA had no effect on the induction of either oleosin or [delta]15 desaturase transcripts. To our knowledge, this is the first report of the biological activity of 8[prime]-OH ABA and of stimulatory effects of (+)-ABA and 8[prime]-OH ABA on lipid and oleosin biosynthesis.

Alteration of seed fatty acid composition by an ethyl methanesulfonate-induced mutation in Arabidopsis thaliana affecting diacylglycerol acyltransferase activity

In characterizing the enzymes involved in the formation of very long-chain fatty acids (VLCFAs) in the Brassicaceae, we have generated a series of mutants of Arabidopsis thaliana that have reduced VLCFA content. Here we report the characterization of a seed lipid mutant, AS11, which, in comparison to wild type (WT), has reduced levels of 20:1 and 18:1 and accumulates 18:3 as the major fatty acid in triacylglycerols. Proportions of 18:2 remain similar to WT. Genetic analyses indicate that the fatty acid phenotype is caused by a semidominant mutation in a single nuclear gene, designated TAG1, located on chromosome 2. Biochemical analyses have shown that the AS11 phenotype is not due to a deficiency in the capacity to elongate 18:1 or to an increase in the relative delta 15 or delta 12 desaturase activities. Indeed, the ratio of desaturase/elongase activities measured in vitro is virtually identical in developing WT and AS11 seed homogenates. Rather, the fatty acid phenotype of AS11 is the result of reduced diacylglycerol acyltransferase activity throughout development, such that triacylglycerol biosynthesis is reduced. This leads to a reduction in 20:1 biosynthesis during seed development, leaving more 18:1 available for desaturation. Thus, we have demonstrated that changes to triacylglycerol biosynthesis can result in dramatic changes in fatty acid composition and, in particular, in the accumulation of VLCFAs in seed storage lipids.

[Clinical evaluation of the vulva reconstruction with myocutaneous flap transposition after radical vulvectomy]

Thirty-three cases with carcinoma of vulva were treated in the division of gynecologic oncology from July, 1989 to April, 1994. Out of 33 cases, 18 with stage II or III underwent radical vulvectomy, pelvic and inguinal lymphadenectomy. These were divided into 3 groups based on the different methods of vulval reconstruction: (1) simple suture group (6 cases); (2) cutaneous flap group (4 cases); (3) myocutaneous flap transposition group (8 cases). The large defect area left by radical vulvectomy and inguinal lymphadenectomy was reconstructed by myocutaneous flap, tensor fascia latae flap, in 6 cases and musculus gracilis myocutaneous flap in 2 cases. All the cases in group 1, 2 suffered from breakdown of wounds, infection or necrosis, resulting in long term hospitalization (mean duration 36.3 days), delayed scar pains, and problems in walking or sexual activity. Primary wound-healing was observed in the 6 cases of group 3, wound infection occurred in one case with diabetes and one case of relapse cancer after radiation therapy. The mean duration of hospitalization in group 3 was 20 days, and neither scar pains nor problems in sexual activity was found after a follow up of 6 months to 4 years. One case in this group died of brain metastases of cancer of vulva. The indications and advantages of myocutaneous flap transposition are discussed. It is suggested that myocutaneous flap transposition surgery is clinically one of the best and safest methods for reconstruction of the vulva and it can improve the quality of life.

Asparagine-linked glycosylation in Schizosaccharomyces pombe: functional conservation of the first step in oligosaccharide-lipid assembly

The gene gpt encoding uridine diphosphate N-acetyl-D-glucosamine:dolichol phosphate N-acetylglucosaminylphosphoryltransferase (L-G1PT) was isolated by screening a Schizosaccharomyces pombe genomic DNA library in lambda phage under low-stringency hybridization using the Saccharomyces cerevisiae gene ALG7 as probe. Sequencing 2.4 kb of S. pombe DNA revealed a 1338-bp open reading frame (ORF) encoding a hydrophobic protein of 446 amino acids with a predicted molecular weight of 49,852. The S. pombe protein was 50% identical to the S. cerevisiae protein and 43% identical to the protein from Chinese hamster ovary (CHO) cells. Overexpression of the gpt gene in S. pombe cells increased resistance to tunicamycin 25-fold and increased the specific activity of the enzyme in isolated cell membranes 13-fold. This was accompanied by a 50-fold increase in poly(A)+ RNA hybridizing to the gpt probe. Northern analysis indicated a single 1.8-kb message is transcribed from the gpt gene. The gpt gene is essential for viability of S. pombe. Cells containing a disrupted ORF could be rescued by an expression plasmid containing either the intact S. pombe gpt ORF or the CHO L-G1PT cDNA. The S. pombe gpt gene was mapped to chromosome 2 near top1 and ade1.