[Apoptosis of pancreatic acinar and expression of TNF-alpha mRNA, IL-10 mRNA in rats with acute pancreatitis]

OBJECTIVE

To investigate the apoptosis of pancreatic acinar and the expression of TNF-alpha mRNA, IL-10 mRNA in pancreatic tissue of rats with acute pancreatitis.

METHODS

The model of acute edematous pancreatitis(AEP) was established in 20 rats and that of acute necrotizing pancreatits(ANP) in another 20 by injection of sodium taurocholate into the pancreatic duct. Another 10 normal rats were used as controls. At 12 hours after the induction of pancreatitis, 10 rats in each group were sacrificed. Serum and pancreatic TNF-alpha and IL-10 levels were measured. The expression of TNF-alpha and IL-10 mRNA in pancreas was detected and the apoptotic rate of pancreatic acinar determined.

RESULTS

The apoptotic rate of pancreatic acinar in normal, AEP and ANP groups was 2.98%, 17.29% and 8.39%, respectively. TNF-alpha and IL-10 levels increased after the induction of acute pancreatitis. The level of TNF-alpha was lower while that of IL-10 higher in AEP group than in ANP group. Transcription level of TNF-alpha mRNA in ANP group and that of IL-10 mRNA in AEP group were upregulated.

CONCLUSIONS

The transcription levels of TNF-alpha and IL-10 mRNA in pancreatic tissue of rats with acute pancreatitis are positively correlated with their levels in serum and pancreas, suggesting that the pancreas is the organ to release cytokines. The apoptotic rate of pancreatic acinar is negatively correlated with the severity of disease and apoptosis may be a benign response to pancreatic injury.

Matrine inhibits production and actions of fibrogenic cytokines released by mouse peritoneal macrophages

AIM

To study the effects of matrine (Mat) on production and actions of fibrogenic cytokines from mouse peritoneal macrophages.

METHODS

Mouse peritoneal macrophages were primed with calcimycin 1 micromol/L for 8 h then elicited by lipopolysaccharides (LPS) 100 microg/L for 6 h to induce fibrogenic cytokines. Proliferative and collagen stimulating activity in the macrophage culture supernatants was determined by crystal violet staining assay and [3H]-proline incorporation assay using rat hepatic stellate HSC-T6 cell or mouse fibroblast NIH3T3 cell. Transforming growth factor beta (TGFbeta) activity was measured by [3H]-thymidine incorporation assay using Mv-1-Lu mink lung epithelial cell.

RESULTS

Mat (0.5-2 mmol/L) was shown to significantly inhibit LPS-induced collagen stimulating activities and TGFbeta production (P < 0.01) whereas did not inhibit proliferative activities induced by macrophages. Macrophage conditioned medium (MCM)-driven proliferation and collagen synthesis of HSC-T6 cells as well as NIH3T3 cells were attenuated by Mat (0.5-2 mmol/L) in a concentration-dependent manner.

CONCLUSION

Antifibrotic effects of Mat on hepatic stellate cells may be related to reduction of fibrogenic cytokine production and blockade of their actions.

Antifungal activity of histatin-5 against non-albicans Candida species

Fungicidal effects of histatin-5 against 26 oral isolates belonging to 5 non-albicans Candida species were examined. Fifty microM of histatin-5 killed more than 95% of Candida tropicalis and Candida guilliermondii isolates and more than 90% of Candida parapsilosis and Candida krusei. However, Candida glabrata was less sensitive to the peptide (mean 62.9%). Our results, taken together, demonstrated that histatin-5 possessed the fungicidal activity against Candida species other than C. glabrata.

Candida albicans growth on thermal cycled materials for maxillofacial prostheses in vitro

In the present study, the growth of a single isolate of Candida albicans on saliva-, serum-coated or protein free (uncoated), thermocycled (4-70 degrees C for 1 min, respectively; 0, 1000 and 10 000 times) 15 commercial maxillofacial materials was investigated, by monitoring pH changes in growth media. The inhibitory effect of the tissue conditioners on fungal growth was analysed using three parameters viz: (i) delay in the onset of the rapid decline in pH (ii) reduction in the rate of pH change and (iii) the pH minima reached. In the case of control materials (non-thermocycled and uncoated), significant antifungal effect was observed with two products. However, the antifungal effect of the materials was significantly reduced both by thermal cycling (Analysis of covariance [ANOVA]; P < 0.01) and a layer of protein coating (saliva, P < 0.05; serum, P < 0.01). When the interrelation between three parameters of fungal growth and the surface hydrophobicity of the materials were analysed, minimum pH of fungal growth on 10 000-thermocycled materials correlated well with the contact angles of the materials (Student t-test, P < 0.01), suggesting that thermocycling process reduced the unpolymerized components of the materials which showed the antifungal effects, resulted in that the cell growth depends on the surface hydrophobicity of the specimens. These results, taken together, suggest that the ageing of the materials and the biological fluids of the host enhanced the fungal growth on maxillofacial materials.

A rare premalignant prostate tumor epithelial cell syndecan-1 forms a fibroblast growth factor-binding complex with progression-promoting ectopic fibroblast growth factor receptor 1

The abnormal appearance and age-dependent loss of resident fibroblast growth factor receptor-2 (FGFR2) and gain of activity of FGFR1 in epithelial cells is a hallmark of the slow progression to malignancy in some models of prostate cancer. Pericellular matrix heparan sulfate (HS) is an integral subunit of the FGFR tyrosine kinase complex that restricts activity in absence of FGF, facilitates binding of an activating FGF, and confers specificity for FGF isoforms. In this report, we isolated and purified HS proteoglycan (HSPG) from premalignant prostate tumor epithelial cells based on the ability of the HS chains to form a binary complex with immunoglobulin module II of the ectopic and progression-promoting FGFR1 that was competent to bind FGF. The FGFR1 affinity-purified product exhibited a specific activity of over 600 times that of crude cellular HSPG enriched from cell lysates by ion exchange chromatography. The purified preparation exhibited a single NH(2)-terminal sequence with 11 of 13 residues identical to syndecan-1. The activity of purified recombinant glutathione S-transferase-tagged syndecan-1 expressed in premalignant epithelial cells confirmed that syndecan-1 bears HS chains that exhibit the rare motif that forms the FGF-binding complex with ectopic FGFR1. These results are the first to identify by affinity purification a specific HSPG core protein, the HS chains of which act as an integral subunit of the FGFR complex. The results suggest that syndecan-1 provides HS chains in premalignant epithelial cells to both the FGFR2- and FGFR1-signaling complexes that are integral to their dual roles in progression to malignancy.

A novel chitinase having a unique mode of action from Aspergillus fumigatus YJ-407

Chitinases are produced throughout the growth process of fungi and are thought to play important roles in morphogenesis. Aspergillus fumigatus, is an important pathogen of immunocompromised individuals in which it causes pneumonia and invasive disseminated disease with high mortality; it is also known to produce chitinase. We have induced an exceptionally stable extracellular chitinase in A. fumigatus YJ-407, which could be isolated readily in a homogeneous form by using ammonium sulfate precipitation followed by DEAE-cellulose chromatography and preparative PAGE. The molecular mass of this chitinase was estimated to be 46 000 by SDS/PAGE, and its isoelectric point was pH 5.6. The enzyme was most active at pH 5.0 and 60 degrees C, and was inhibited strongly by Hg2+, Pb2+, Ag+, Fe2+, Mn2+ and Zn2+. The enzyme was stable over a broad pH range 4-8 and below 45 degrees C. Tryptophan and carboxyl groups were found to be essential for the enzyme activity. The Michaelis constants for swollen chitin and chitosan were 1.12 mg.mL-1 and 1.84 mg.mL-1, respectively. The enzyme showed maximum activity towards glycol chitin and partially deacetylated chitosan, and lower activity towards colloidal chitin. Analysis of the hydrolysis product showed that the enzyme has both endo- and exo-hydrolytic activities. In addition, a transglycosyl activity was also observed.

The effect of calcitonin gene-related peptide on pancreatic blood flow and secretion in conscious dogs

The effects of human alpha-calcitonin gene-related peptide (alpha-CGRP) and beta-CGRP on pancreatic arterial (PA), superior mesenteric (SMA) and left gastric arterial (LGA) blood flows were studied by ultrasound transit-time blood flow meters in five conscious dogs. Intravenous injections of alpha-CGRP and beta-CGRP (5-200 pmol/kg) induced a dose-related increase in PA flow and a dose-related decrease in its resistance. At lower doses, alpha-CGRP was more potent than beta-CGRP, but their maximal responses were similar. The blood flow responses to alpha-CGRP (200 pmol/kg) were 153% of the basal flow in LGA, 313% in PA, and 534% in SMA, while those to VIP (100 pmol/kg) were 467% in LGA, 953% in PA and 163% in SMA. Somatostatin reduced blood flow in all arteries. alpha-CGRP, but not beta-CGRP, at higher doses induced gastric contractions and pancreatic protein-rich secretion, which were blocked by atropine. These results suggest that CGRP in perivascular nerves in the pancreas may regulate pancreatic blood flow in dogs but its physiological function remains to be studied.

[Cloning and expression of maltooligosyltrehalose synthase from Sulfolobus acidocaldarius in Escherichia coli]

The gene of MTSase (maltooligosyltrehalose synthase) from Sulfolobus acidocaldarius ATCC49426 was amplified by PCR. The primers were designed according to the published sequence of homologous gene from Sulfolobus acidocaldarius ATCC33909. This gene was inserted into the plasmid pBV220 and the resultant recombinant plasmid pBV220-GT was transformed to E. coli DH5 alpha. The activity of recombinant enzyme was about 10 u/g(wet cell). In order to improve the expression level of target protein, some nucleotides in the 3' and 5' of the gene were modified to optimize the second structure of mRNA by PCR amplification using the new primers devised according to the biosoftware GOLDKEY2.0. As a result, the activity of recombinant enzyme increase to 19.8 u/g(wet cell). Then, the helping plasmid pUBS520 which carried the gene encoding the tRNA of rare codons AGG and AGA was transformed to the recombinant strain. But it took little effect.

Role of cholecystokinin in the intestinal phase of pancreatic circulation in dogs

The regulatory mechanisms of postprandial pancreatic hyperemia are not well characterized. The aim of this study is to clarify the role of cholecystokinin (CCK) in the intestinal phase of pancreatic circulation. Pancreatic, gastric, and intestinal blood flows were measured by ultrasound transit-time blood flowmeters in five conscious dogs. Pancreatic and gastric secretion and blood pressure were also monitored. Synthetic CCK octapeptide (CCK-8) or gastrin heptadecapeptide (gastrin-17) was infused intravenously, and milk was infused into the duodenum with or without loxiglumide, a specific CCK-A receptor antagonist. CCK-8 induced dose-related increases of pancreatic, but not gastric or intestinal, blood flow and protein secretion without affecting systemic blood pressure. Gastrin-17 did not affect pancreatic blood flow. An intraduodenal infusion of milk increased pancreatic and intestinal blood flows and pancreatic protein secretion. Loxiglumide completely inhibited pancreatic blood flow and protein responses to CCK-8 and milk but not the intestinal blood flow response. CCK is a potent and specific pancreatic vasodilator, with its effect mediated by CCK-A receptors. CCK plays an important role in the regulation of the intestinal phase of the pancreatic circulation in dogs.

[Non-invasive prenatal diagnosis of Duchenne muscular dystrophy]

OBJECTIVE

This paper was designed to investigate the feasibility of non-invasive prenatal diagnosis of Duchenne muscular dystrophy(DMD).

METHODS

The nucleated red blood cells(NRBC) were separated with percoll using a discontinuous density gradient method. The cells were smeared on microscope slides using a cyto-centrifuge and then stained by Wright- Giemsa. NRBCs were detected and individually retrieved into glass capillary pipettes using a micromanipulator under microscopic observation. The whole genome of a single cell was amplified by improved primer extension preamplification(PEP). The procedures for making prenatal diagnosis of DMD and determining the origin of NRBCs proceeded at the same time using sex determination and linkage analysis of several STR loci of dystrophin. Genotypes were analyzed by amplifying the 9 STR fragments using fluorescence-PCR technique and NRBCs origin was further determined.

RESULTS

A case of DMD in male fetus was diagnosed.

CONCLUSION

With the use of the method reported, the non-invasive prenatal diagnosis of DMD is possible.

Heteronuclear nuclear magnetic resonance assignments, structure and dynamics of SUMO-1, a human ubiquitin-like protein

The structure of a ubiquitin-like protein, small ubiquitin-related modifier-1 (SUMO-1), was earlier determined using homonuclear nuclear magnetic resonance (NMR) spectroscopy, since the spectral quality of the protein was not suitable for heteronuclear NMR data collection. In this study, a slightly different construct of the SUMO-1 gene was used for protein over-expression. The protein purified from this construct showed high spectral qualities, therefore, multi-dimensional heteronuclear NMR data for a dynamic study and structural determination were acquired. The structure of SUMO-1 obtained in this study differs in several respects from the structure obtained from homonuclear NMR data. Furthermore, structural differences were observed between the new SUMO-1 and ubiquitin structures. These differences may be important for SUMO-1-specific recognition in cells. Additionally, relaxation parameters indicate that SUMO-1 undergoes highly anisotropic tumbling in solution and that the long amino (N)-terminal sequence of SUMO-1 is highly dynamic with increasing flexibility towards the end.

The nonsense-mediated decay pathway and mutually exclusive expression of alternatively spliced FGFR2IIIb and -IIIc mRNAs

Exons IIIb and IIIc of the FGFR2 gene are alternatively spliced in a mutually exclusive manner in different cell types. A switch from expression of FGFR2IIIb to FGFR2IIIc accompanies the transition of nonmalignant rat prostate tumor epithelial cells (DTE) to cells comprising malignant AT3 tumors. Here we used transfection of minigenes with and without alterations in reading frame and with and without introns to examine how translation affects observed FGFR2 splice products. We observed that nonsense mutations in other than the last exon led to a dramatic reduction in mRNA that is abrogated by removal of downstream introns in both DTE and AT3 cells. The mRNA, devoid of both IIIb and IIIc exons (C1-C2), is a major splice product from minigenes lacking an intron downstream of the second common exon C2. From these observations, we suggest that repression of exon IIIc and activation of exon IIIb inclusion in DTE cells lead to the generation of both C1-IIIb-C2 and C1-C2 products. However, the C1-C2 product from the native gene is degraded due to a frameshift and a premature termination codon caused by splicing C1 and C2 together. Derepression of exon IIIc and repression of exon IIIb lead to the generation of both C1-IIIc-C2 and C1-C2 products in AT3 cells, but the C1-C2 product is degraded. The C1-IIIb-IIIc-C2 mRNA containing a premature termination codon in exon IIIc was present, but at apparently trace levels in both cell types. The nonsense-mediated mRNA decay pathway and cell type-dependent rates of inclusion of exons IIIb and IIIc result in the mutually exclusive expression of FGFR2IIIb and IIIc.

Characterization of chromosome aberrations in salivary gland tumors by FISH, including multicolor COBRA-FISH

Fluorescence in situ hybridization (FISH), including COBRA-FISH, was used to characterize 11 salivary gland tumors that had been investigated by banding analysis. Five cases were pleomorphic adenoma (PA), three were adenoid cystic carcinoma, and one case each was mucoepidermoid carcinoma, carcinoma ex-pleomorphic adenoma (CaPA), and adenocarcinoma. All 11 cases were selected on the basis that they had shown rearrangement of 6q or 9p or had unresolved aberrations after karyotyping. The COBRA-FISH and FISH analyses led to a revised karyotype in all informative cases and made it possible to clarify almost all chromosomal rearrangements occurring in the tumors. Of particular note were the confirmation of the existence of 6q deletions, a common change in salivary gland carcinomas, and the demonstration that a seemingly balanced t(6;9) resulted in del(6q). Other rearrangements that were revealed by FISH included amplification of 12q sequences (MDM2 and CDK4) in one PA. We also investigated the status of the PLAG1 gene in four cases (one PA, one CaPA, one adenoid cystic carcinoma, and one mucoepidermoid carcinoma) with 8q12 rearrangements. Only in the former two cases were the FISH results compatible with intragenic rearrangements. Overall, the results of the study show that, even with good banding quality and in karyotypes of modest complexity, much new information will be gained by supplementing the banding analysis with a multicolor FISH approach, such as COBRA-FISH.

Identification of mouse Jun dimerization protein 2 as a novel repressor of ATF-2

A mouse cDNA that encodes a DNA-binding protein was identified by yeast two-hybrid screening, using activating transcription factor-2 (ATF-2) as the bait. The protein contained a bZIP (basic amino acid-leucine zipper region) domain and its amino acid sequence was almost identical to that of rat Jun dimerization protein 2 (JDP2). Mouse JDP2 interacted with ATF-2 both in vitro and in vivo via its bZIP domain. It was encoded by a single gene and various transcripts were expressed in all tested tissues of adult mice, as well as in embryos, albeit at different levels in various tissues. Furthermore, mouse JDP2 bound to the cAMP-response element (CRE) as a homodimer or as a heterodimer with ATF-2, and repressed CRE-dependent transcription that was mediated by ATF-2. JDP2 was identified as a novel repressor protein that affects ATF-2-mediated transcription.

Mannosylerythritol lipid induces characteristics of neuronal differentiation in PC12 cells through an ERK-related signal cascade

Rat pheochromocytoma PC12 cells undergo neuronal differentiation in response to nerve growth factor (NGF). The differentiation involves protein kinase cascades that include the kinases MEK and ERK, as well as activation of the transcription factors c-Jun and c-Fos. We show here, that exposure of PC12 cells to mannosylerythritol lipid (MEL), a yeast extracellular glycolipid, enhances the activity of acetylcholinesterase and interrupts the cell cycle at the G1 phase, with resulting outgrowth of neurites and partial cellular differentiation. Treatment with MEL stimulates the phosphorylation of ERK to a similar extent as treatment with NGF, although, the appearance of phosphorylated ERK is somewhat delayed. Both the MEL-induced outgrowth of neurites and the increase in the activity of acetylcholinesterase are prevented by PD98059, a specific inhibitor of MEK. Northern blotting analysis of c-jun transcripts and analysis of transcription in PC12 cells of a c-jun/CAT reporter construct demonstrated a significant increase in the rate of transcription of the c-jun gene upon treatment with MEL. The sequence elements required for the MEL-mediated activation of transcription of the c-jun gene are located between nucleotides -126 and -79 in the 5' flanking region. Our results suggest that MEL induces characteristics of neuronal differentiation in PC12 cells, with transactivation of the c-jun gene, via an ERK-related signal cascade that is partially overlapping the pathways activated in response to NGF. These results might provide the groundwork for the use of microbial extracellular glycolipids as novel reagents for the treatment of cancer cells.

Growth of Candida species on commercial denture adhesives in vitro

PURPOSE

Although denture adhesives are widely used by the elderly, it is unknown whether denture adhesives support microbial growth. Therefore, we investigated the growth of Candida species on six commercial denture adhesives.

MATERIALS AND METHODS

The growth of a single isolate of C albicans and C tropicalis on six commercial denture adhesives was investigated by monitoring pH changes in growth media.

RESULTS

In the preliminary study, the effect of each product on the pH value of the medium was examined; a single product itself significantly reduced the pH of medium below 5.0. When the yeast was grown on the materials, the pH changes in the media varied depending on the adhesive materials and, to a greater or lesser extent, on whether they showed antifungal activity. Two products (Cushion Collect and Collect Soft A) significantly suppressed C albicans growth (P < 0.01), and one product (Collect Soft A) effectively reduced C tropicalis growth (P < 0.01).

CONCLUSION

Our results suggest that denture adhesives possess antifungal activity to a greater or lesser degree. However, one product caused the reduction of pH below 5.0. Thus, in the daily use of denture adhesives, attention should be paid to both the materials and their microbiologic properties.

Identification of metabolites of phytosterols in rat feces using GC/MS

Beta-sitosterol, campesterol and stigmasterol have been known to the phytosterols the most frequently found in plants. Metabolism of phytosterols was investigated using rat feces and liver microsomes. Feces were collected after phytosterols (a well characterized mixture of beta-sitosterol 40%, campesterol 30% and dihydrobrasicasterol) were administered orally (0.5 g/kg) to rats. Metabolites of phytosterols were identified using GC/MS. Three peaks were eluted at 12.47, 12.65, 12.87 min and had characteristic molecular ions m/z 428, 430, 432, respectively. Three fecal metabolites were identified as androstadienedione, androstenedione, and androstanedione. No metabolites could be detected in the rat liver microsomal reaction mixture. The results suggest that the metabolites of phytosterols in rat feces are formed by oxidation at 3- position, saturation at 5- and 6- position, and 17- side chain cleavage in the rat large intestine.

Centromere cleavage is a mechanism underlying isochromosome formation in skin and head and neck carcinomas

Centromeric rearrangements, in the form of isochromosomes or whole-arm translocations, are the most common recurrent changes in head and neck and skin carcinomas. Little is known about the mechanisms behind the origin of these chromosome rearrangements. In the present study, one basal cell carcinoma and two squamous cell carcinomas of the head and neck were thoroughly studied by cytogenetic and fluorescence in situ hybridization techniques. All tumors showed intratumor heterogeneity in the form of cytogenetically related subclones (in all tumors) and unrelated clones (in one tumor). Assessment of karyotypic evolution in these tumors suggests that centromeric cleavage is a mechanism giving rise to isochromosomes. A similar mechanism may also be involved in the formation of whole-arm translocations.

[The effect of methylenum coeruleum in laparoscope cholecystectomy]

OBJECTIVES

To help the operator correctly judge in operation the cystic gall duct and choledoch, and eliminate the operation wound.

METHODS

To divide laparoscope cholecystectomy patients with the same weight at the same period into two groups: development group (589 cases) using methylenum coeruleum and conducting cholecysto-puncture visualization during the operation in which colors of cholecyst, cystic gall duct and choledoch turn blue; comparative group (553 cases) using regular laparoscope cholecystectomy.

RESULTS

The two groups differed remarkably in operation time, complication, and transferring rate (P < 0.01).

CONCLUSIONS

Methylenum coeruleum development technology in operation is a kind of visualization to help the operator judge in operation Calot triangular anatomy construction correctly, reduce the operation time obviously, and increase the rate of success.

Biological function of a novel gene overexpressed in human hepatocellular carcinoma

OBJECTIVE

To clone the full-length of a differentially expressed cDNA fragment, LC27, and study its biological function tentatively.

METHODS

Northern blot was used to analyze the expression pattern of LC27 in hepatocellular carcinoma, matched nontumor liver tissues, fetal liver and normal adult liver tissues, as well as BEL-7402 hepatocellular carcinoma cell line ESTs splicing and 5' rapid amplification of cDNA ends (5' RACE) were used to clone the full-length of LC27 cDNA. An antisense oligodeoxynucleotide approach was used to investigate the biological role of the gene in the proliferation of BEL-7402 cells.

RESULTS

A 2186 bp novel cDNA with an open reading frame encoding a 283 amino acid protein was cloned. Analysis of the deduced amino acid sequence indicated that it is 38% (88/229) identical to human Golgi 4-transmembrane spanning transporter MTP. The gene and the encoded protein was termed hepatocellular carcinoma overexpressed transmembrane protein (hotp) and HOTP, respectively. Hotp mRNA was almost undetectable in normal adult liver and fetal liver tissues. However, it was significantly up-regulated in hepatocellular carcinoma and some matched nontumor liver tissues, as well as BEL-7402 cells. The proliferation of BEL-7402 cells was suppressed by an antisense oligodeoxynucleotide against hotp mRNA at a concentration of 50 micrograms/ml.

CONCLUSION

HOTP may be an integral membrane transporter protein. The overexpression of the gene in hepatocellular carcinoma may play an important role in hepatocarcinogenesis and disease progression.

A telehealth project for supporting an isolated physiotherapist in a rural community of Hokkaido

Almost all towns and villages in the rural areas of Hokkaido suffer shortages of health-care professionals, particularly therapists (e.g. physiotherapists, occupational and speech therapists). A therapist in a rural community must work as a general rehabilitation therapist. This adds to the stress of both the responsibility and the isolation and it seems to be the major reason why therapists do not generally stay in rural communities. A telehealth project to overcome this vicious circle in Hokkaido was started at Sapporo Medical University in 1997, and the town of Betsukai joined the project. This outlines the support given to an isolated physiotherapist working in Betsukai, as part of a larger rehabilitation project. Regular videoconferences helped the physiotherapist gain confidence in her work in the rural community.

Consultation-liaison psychiatry training and supervision results in fewer recommendations for constant observation

In this study, we tested two hypotheses. First, that consultation-liaison (C-L)-trained psychiatry residents would order constant observation (CO) less frequently than psychiatry residents untrained in C-L. Second, we predicted that CO would be ordered less frequently under circumstances when experienced C-L psychiatry attending and fellows would be available to supervise psychiatry residents training in C-L. We reviewed a total of 138 consultations during a 6-month period. Constant observation was recommended in 31 cases (22.5%). Consultations were done by residents who had received training in C-L psychiatry (n=34) and by residents who were not trained in C-L (n=34). Residents not trained in C-L had a significantly higher percentage of CO orders (44.1%) compared to those trained in C-L (15.4%) (chi(2)=12.1, df=1, P<0.001). Because C-L-trained residents provided regular-hour and after-hour consults while residents without C-L training provided only after-hour consults, we also separately analyzed data from the 102 after-hour cases. We again found that residents with C-L training had a significantly lower rate of ordering CO (22.1%) than those who had not yet received C-L psychiatry training (44.1%) (chi(2)=5.31, df=1, P<0.05). We also found that C-L-trained residents ordered CO less frequently during regular hour consults (2.8%) when experienced staff are available in supervision compared to after hours (22.1%) (chi(2)=6.72, df=1, P<0.01). Our findings suggest that training in C-L psychiatry has a significant impact on the use of constant observation for patients in the general hospital thereby reducing the cost of care.

Neural system identification model of human sound localization

This paper examines the role of biological constraints in the human auditory localization process. A psychophysical and neural system modeling approach was undertaken in which performance comparisons between competing models and a human subject explore the relevant biologically plausible "realism constraints." The directional acoustical cues, upon which sound localization is based, were derived from the human subject's head-related transfer functions (HRTFs). Sound stimuli were generated by convolving bandpass noise with the HRTFs and were presented to both the subject and the model. The input stimuli to the model were processed using the Auditory Image Model of cochlear processing. The cochlear data were then analyzed by a time-delay neural network which integrated temporal and spectral information to determine the spatial location of the sound source. The combined cochlear model and neural network provided a system model of the sound localization process. Aspects of humanlike localization performance were qualitatively achieved for broadband and bandpass stimuli when the model architecture incorporated frequency division (i.e., the progressive integration of information across the different frequency channels) and was trained using variable bandwidth and center-frequency sounds. Results indicate that both issues are relevant to human sound localization performance.

Cloning and sequencing of sialyltransferase gene from human fetal liver

Based on sequences of the highly conserved segments in the previously cloned sialyltransferases, 150 bp fragments were amplified and sequenced using human fetal liver mRNA as template. One of them (s38) showed 57%-97% identities with the active domains of previously cloned sialyltransferases. Based on the sequence of s38, an oligonucleotide was synthesized and labeled to screen human fetal liver cDNA library. A cDNA encoding alpha 2, 3-sialyltransferase has been isolated. The cDNA sequence included an open reading frame coding for 340 amino acid residues, and the deduced amino acid sequence showed 100% identity with that of human submaxillary gland Gal beta 1, 3GalNAc alpha 2, 3-sialyltransferase, 83.2% identity with that of pig submaxillary gland alpha 2, 3-sialyltransferase. These results suggested that the protein encoded by the cDNA from human fetal liver cDNA library was a Gal beta 1, 3GalNAc alpha 2, 3-sialyltransferase.

Pharmacological characterization of (10bS)-1,2,3,5,6,10b-hexahydropyrrolo[2,1-a]isoquinoline oxalate (YSL-3S) as a new alpha2-adrenoceptor antagonist

Alpha2-adrenoceptor antagonists, which can enhance synaptic norepinephrine levels by blocking feedback inhibition processes, are potentially useful in the treatment of disease states such as depression, memory impairment, impotence and sexual dysfunction. (10bS)-1,2,3,5,6,10b-Hexahydropyrrolo[2,1-a]isoquinoline oxalate (YSL-3S) was evaluated in several in vitro biological tests to establish its pharmacological profile of activities as an alpha2-adrenoceptor antagonist. Saturation binding assay revealed that [3H]rauwolscine bound to the alpha2-adrenoceptors with a Kd value of 6.3+/-0.5 nM and a Bmax value of 251+/-39 fmol/mg protein in rat cortical synaptic membranes. Competitive binding assay showed that YSL-3S inhibited the binding of [3H]rauwolscine (1 nM) in a concentration-dependent manner with a Ki value of 98.2+/-12.1 nM while it did not inhibit the binding of [3H]cytisine (1.25 nM) to neuronal nicotinic cholinergic receptors. The Ki values of yohimbine, clonidine and norepinephrine for [3H]rauwolscine binding were 15.8+/-1.0, 40.1+/-5.9 and 40.0+/-11.5 nM, respectively. In addition, the binding affinity of YSL-3S for alpha2-adrenoceptors was higher than that of its antipode and the racemic mixture. The functional activity of YSL-3S at the presynaptic alpha2-adrenoceptors was assessed using the prostatic portion of the rat vas deferens. Clonidine inhibited field-stimulated contractions of the vas deference in a dose-dependent manner. The presence of YSL-3S or yohimbine caused a parallel, rightward the dose-response curve of clonidine in a dose-dependent manner, indicating an antagonistic action at the presynaptic alpha2-adrenoceptors. The pA2 values of yohimbine and YSL-3S were 7.66+/-0.13 and 6.64+/-0.18, respectively. The results indicate that YSL-3S acts as a competitive antagonist at presynaptic alpha2-adrenoceptors with a potency approximately ten times lower than yohimbine, but is devoid of binding affinity for neuronal nicotinic cholinergic receptors.

Syntheses and binding affinities of 6-nitroquipazine analogues for serotonin transporter. Part 1

6-Nitroquipazine has been known as one of the most potent and selective inhibitors of serotonin transporter in vitro and in vivo. Nine derivatives of 6-nitroquipazine were synthesized and tested for their potential abilities to displace [3H]citalopram binding to the rat cortical membranes.

Environmental fluoride content in Tibet

As the first report of the environmental fluoride level in Tibet, the determination by the fluoride ion-selective electrode method of fluoride concentration in water, soil, fuel, grains, food, vegetables, and tea was made for the Tibetan people living on various land types with various ecological characteristics. The average level of fluoride concentration in water in Tibet was 0.06 mg/L; the level of dissolved fluoride in the soil was 0.45 mg/kg; the fluoride concentration in main fuels was 0.10 mg/kg; the levels in main grains, food, and vegetables were 0.06-0.33 mg/kg; those in buttered tea and Zanba mixed with brick tea were 3.09-3.61 mg/kg; and water-dissolved fluoride concentrations in the brick tea produced in Sichuan Province and Yunan Province were 533.89-617.32 mg/kg. Tibet is the prevailing area of brick tea fluorosis.

[Identification of high-lying odd energy levels of uranium by resonant ionization mass spectrometry]

Single-colour and two-colour multiphoton resonant ionization spectra of uranium atom were studied extensively with a Nd:YAG laser-pumped dye laser atomic beam apparatus time-of-flight mass spectrometer in our laboratory. The energy locations of high-lying odd-parity levels in the region 33,003-34,264 cm-1, measured by a two-colour three-step ionization technique, were reported here. The angular momentum quantum number J was uniquely assigned for these levels by using angular momentum selection rules.

[Cloning and expression of the gene encoding novel alpha-amylase from Sulfolobus shibatae in E. coli]

A novel alpha-amylase gene was amplified from Sulfolobus shibatae by using PCR technique. The amplified 1.7 kb DNA fragment was inserted into an expression vector pBV220 to yield the recombinant plasmid pSBAM. The novel alpha-amylase gene in pSBAM was expressed in E. coli. The production of the novel alpha-amylase activity reached over 8 units/100 mL of the culture. The molecular weight of this enzyme was about 61 kD by SDS-PAGE. The expressed novel alpha-amylase protein in E. coli DH5 alpha accounted for about 20% of the total protein in the recombinant cell. The cooperative action of the novel alpha-amylase and the maltooligosyltrehalose synthase from Sulfolobus shibatae was investigated and trehalose was detected by using HPLC analysis when using amylose and partial starch hydrolysates as substrates.

Elevated cholesterol metabolism and bile acid synthesis in mice lacking membrane tyrosine kinase receptor FGFR4

Heparan sulfate-regulated transmembrane tyrosine kinase receptor FGFR4 is the major FGFR isotype in mature hepatocytes. Fibroblast growth factor has been implicated in the definition of liver from foregut endoderm where FGFR4 is expressed and stimulation of hepatocyte DNA synthesis in vitro. Here we show that livers of mice lacking FGFR4 exhibited normal morphology and regenerated normally in response to partial hepatectomy. However, the FGFR4 (-/-) mice exhibited depleted gallbladders, an elevated bile acid pool and elevated excretion of bile acids. Cholesterol- and bile acid-controlled liver cholesterol 7alpha-hydroxylase, the limiting enzyme for bile acid synthesis, was elevated, unresponsive to dietary cholesterol, but repressed normally by dietary cholate. Expression pattern and cholate-dependent, cholesterol-induced hepatomegaly in the FGFR4 (-/-) mice suggested that activation of receptor interacting protein 140, a co-repressor of feed-forward activator liver X receptor alpha, may mediate the negative regulation of cholesterol- and bile acid-controlled liver cholesterol 7alpha-hydroxylase transcription by FGFR4 and cholate. The results demonstrate that transmembrane sensors interface with metabolite-controlled transcription networks and suggest that pericellular matrix-controlled liver FGFR4 in particular may ensure adequate cholesterol for cell structures and signal transduction.

[cDNA cloning, sequence analysis of trehalose-6-phosphate synthase gene from Saccharomyces cerevisiae AS2.1416]

The trehalose-6-phosphate synthase gene tps1 was amplified from yeast S. cerevisiae AS2.1416 cDNA library by polymerase chain reaction. This 1.5 kb fragment was cloned into PstI and BamHI sites of pGEM-T easy vector and the sequence of the gene indicated the cloned tps1 gene contained 1485 nucleotides encoding for 495 amino acid and shared a sequence homology of 99.6% with that from S. cerevisiae S288C.

Nonrandom pattern of cytogenetic abnormalities in squamous cell carcinoma of the larynx

Cytogenetic analysis of short-term cultures from 105 squamous cell carcinomas of the larynx (LSCC) revealed clonal chromosome aberrations in 56 tumors. Simple karyotypic changes (less than four aberrations per clone) were found in 24 cases, and the remaining 32 tumors had complex karyotypes with multiple numerical as well as unbalanced structural rearrangements. Extensive intratumor heterogeneity, in the form of multiple related subclones or unrelated clones, was observed in a large fraction of the tumors. The structural changes most often affected chromosomes 3, 1, 11, 7, 2, 15, 5, 4, 8, and 12, with rearrangements in the centromeric regions, i.e., the centromeric bands p10 and q10 and the juxtacentromeric bands p11 and q11, accounting for 43% of the total breakpoints. The most common imbalances brought about by numerical and unbalanced structural rearrangements were loss of chromosomal region 3p21-pter, chromosome arms 4p, 6q, 8p, 10p, 13p, 14p, 15p, and 17p, and gain of chromosomal regions 3q21-qter, 7q31-pter, and 8q. Among 17 recurrent aberrations identified, the most common were i(8q), hsr(11)(q13), i(3q), i(5p), and del(3)(p11). No statistically significant association was found between major karyotypic features and histological differentiation or TNM stage. The karyotypic features of the LSCC were also compared with previously published oral SCC, a subgroup of SCC that has been more extensively characterized cytogenetically. No clear-cut karyotypic differences were found between LSCC and oral SCC, with the exception that i(8q) was significantly more frequent among the latter.

Purification and properties of genetic expressing product of thermostable protease from Bacillus stearothermophilus HY-69

The thermostable metal protease gene from Bacillus stearothermophilus HY-69 had been cloned and expressed in Bacillus subtilis MI113. The genetic expressing product of the enzyme was purified by CM-cellulose chromatography. The product shows homogeneity on PAGE. Its molecular weight is 27,000 +/- 1000 by SDS-PAGE and Sephadex G100 filtration, respectively. The alpha-helix content of the protease is estimated to be about 66%, the beta-turn about 28%, the random coil about 6%, but not beta-sheet, calculated from the circular dichroism data. The optimal temperature of the enzyme was 70 degrees C. When the enzyme was denatured in 3 mol/L of Gdn--HCl in phosphate buffer pH6.0 for 20 min, it remained about 40% of original activity. It shows that it is rather resistant to heat and Gdn-HCl denaturation. Its conformational variety coursed by Gdn-HCl was investigated by the far UV circular dichroism and fluorescence spectra. The results show that the enzyme has more compact conformation and internal hydrophobility.

[The effects of electroporation-mediated erythropoietin (EPO) gene transfer into skeleton muscle on renal anemia]

OBJECTIVE

To investigate the effects of erythropoietin (EPO) gene transfer into skeleton muscle mediated by electroporation on renal anemia.

METHODS

Renal failure models were created by adenine-excessive diet (150 mg per day). Plasmid vectors encoding EPO were transferred by electroporation after 80 days when mean blood urea nitrogen level (BUN) had increased from 3.4 mmol/L +/- 1.3 mmol/L to 18.1 mmol/L +/- 4.1 mmol/L and the hematocrit had decreased from 45.6% +/- 2.1% to 25.4% +/- 3.7%. During the process of treatment, adenine-excessive diet was given. Hb, HCT, BUN and Cre in blood were tested by automatic analyzer; EPO level in the serum was tested by EPO ELISA kit, EPO gene expression was proved by RT/PCR. The survival rate was calculated.

RESULTS

Hematocrit increased to 34.4% +/- 7.5% only 7 days after the treatment and reached 91.4% of normal level (46% +/- 2%) after 5 weeks. The survival rate of test models after 9 weeks was 77.8%, which was remarkably higher than that of controls (16.7%). mRNA level of EPO gene expression was indicated by RT/PCR.

CONCLUSION

Electroporation can increase the efficiency of EPO gene transfer and thus greatly improve hematocrit in mice and prolong the life-span of chronic renal anemia models. This method can provide a new way for treatment of EPO-responsive anemias.

Universal learning network and its application to chaos control

Universal Learning Networks (ULNs) are proposed and their application to chaos control is discussed. ULNs provide a generalized framework to model and control complex systems. They consist of a number of inter-connected nodes where the nodes may have any continuously differentiable nonlinear functions in them and each pair of nodes can be connected by multiple branches with arbitrary time delays. Therefore, physical systems, which can be described by differential or difference equations and also their controllers, can be modeled in a unified way, and so ULNs may form a super set of neural networks and fuzzy neural networks. In order to optimize the ULNs, a generalized learning algorithm is derived, in which both the first order derivatives (gradients) and the higher order derivatives are incorporated. The derivatives are calculated by using forward or backward propagation schemes. These algorithms for calculating the derivatives are extended versions of Back Propagation Through Time (BPTT) and Real Time Recurrent Learning (RTRL) of Williams in the sense that generalized node functions, generalized network connections with multi-branch of arbitrary time delays, generalized criterion functions and higher order derivatives can be deal with. As an application of ULNs, a chaos control method using maximum Lyapunov exponent of ULNs is proposed. Maximum Lyapunov exponent of ULNs can be formulated by using higher order derivatives of ULNs, and the parameters of ULNs can be adjusted so that the maximum Lyapunov exponent approaches the target value. From the simulation results, it has been shown that a fully connected ULN with three nodes is able to display chaotic behaviors.

Identification of connexin-interacting proteins: application of the yeast two-hybrid screen

Protein-protein interactions are recognized as one of the fundamental mechanisms for relaying the intra- and intercellular signals that are required for normal cellular activities affecting growth, development, and maintenance of homeostasis in tissues and organs. The yeast two-hybrid screen has become a valuable tool for identifying protein-protein interactions. The gap junction protein connexin 43 (Cx43) has been implicated in a number of biological processes including development and cellular growth control. To further advance our understanding of the ways in which Cx43 may influence these cellular activities, and to extend our knowledge of the regulation of Cx43 function and/or processing, we have employed the yeast two-hybrid screen technique to identify Cx43-interacting proteins. We present detailed methods for the yeast two-hybrid screen of a mouse embryonic cDNA library using the C terminus of Cx43 as "bait." We also describe additional methods to confirm the interactions between Cx43 and the identified proteins. These methods include in vitro binding assays, coimmunoprecipitation, and subcellular localization using immunofluorescence microscopy.

[Cloning and expression of the gene encoding maltoologosyl trehalose synthase from Sulfolobus shibatae in E. coli]

2.2 kb DNA fragment encoding a novel enzyme, maltooligosyl trehalose synthase (MTSase) was amplified from Sulfolobus shibatae by using PCR technique. The amplified 2.2 kb DNA fragment was inserted into an expression vector, pBV220, to yield the recombinant plasmid pSBGT1. MTSase gene in pBSGT1 was expressed in E. coli. The molecular weight of expressed MTSase detected by SDS-PAGE was about 74 kD, which is conformed with that deduced from nucleotide sequence. The expressed MTSase protein accounted for about 4.4% of the total cell protein. The MTSase from transformants containing pBSGT1 is capable of decreasing DE value, forming non-reducing or less-reducing saccharides when allowed to act on reducing partial starch hydrolysates.

[The multicolour three-photon resonant ionization spectrum studies in uranium atom]

The multicolour three-photon resonant ionization spectra of 238U were measured by using the pulsed dye lasers system synchronously pumped by a frequency doubled Nd:YAG-laser 532 nm output(operated at 10 Hz), a device for atomic beam of U, time-of-flight mass spectrometer and boxcar integrator. The dye laser pulses have a 6 ns duration. Beams from the dye lasers, which have the same polarization direction and are focused by lenses, entered an interaction chamber through opposite windows on a common axis and spatially overlapped the U atomic beam. The optical pulse from dye laser DL2 was delayed to arrive at the interaction region 8 ns after the pulse from dye laser DL1; in the same way, the pulse from DL3 was delayed 8 ns after from DL2. The atomic beam device was made from stainless steel. We generated the U vapor by heating solid U in a graphite crucible by e-type electron-field on first excited states were studied in uranium atom. The question how to determine single-colour, two-colour and three-colour three-photon resonant ionization peak in the three-colour three-photon resonant ionization spectra diagram were solved.

[Individual biomass of natural Pinus densiflora]

The aboveground biomass of individuals with different growth potentials in natural Pinus densiflora forest with different stand densities was measured in Yanbian, Jilin Province. The variation of individual biomass affected by densities was in order of dominant tree < intermediate tree < suppressed tree, while the distribution proportion of biomass in different organs affected by densities was: in order of trunk > branch > needle > bark. The biomass components of P. densifliora with different growth potentials varied markedly with the approaching of density class III, and the change of intermediate trees was similar to the whole stand. The vertical distributions of biomass of different trees were different from each other, but all showed that the biomass of trunks and barks was mainly distributed below 6 m high from ground, that of branches was within 6-10 m high, that of needles was uniform in the upper, middle and lower layers, and that of branches and needles in upper layer was least affected by density.

[Spectral characteristics of solar radiation in broadleaved Korean pine forest in Changbai Mountain]

Based on the measurement above and below forest canopy and meteorological data, the spectral characteristics of solar radiation in broadleaved Korean pine forest in Changbai Mountain was analyzed. The results show that the photosynthetically active radiation(PAP) coefficients of total radiation, direct radiation and scatter radiation changed daily and yearly, with an annual averages of 0.46, 0.43 and 0.56 respectively. The average reflectivity, transmissitvity and absorptivity of single leaves of different tree species in Korean pine forest were 27.0%, 23.4%, 49.6% respectively. Single leaves nearly absorbed all of the ultraviolet radiation(UV) and 71.8% of photosynthetically active radiation, but transmitted 9.6% and reflected 18.6%. As for near-infrared radiation (NIR), the reflectivity and transmissitivity of leaves were a little less than the absorptivity. The forest canopy absorbed 93.9% PAR and 94.1% UV, but reflected and transmitted less. It absorbed 59.2%, reflected 26.3% and transmitted 14.4% NIR.

Interactions between thermal cycled resilient denture lining materials, salivary and serum pellicles and Candida albicans in vitro. Part II. Effects on fungal colonization

In the present study, the growth of a single isolate of Candida albicans on saliva-, serum-coated or protein free (uncoated), thermocycled (4-70 degrees C for 1 min, respectively; 0, 1000 and 10 000 times) seven commercial soft lining materials were investigated, by adenosine triphosphate (ATP) analysis. In the case of control resilient liners (not thermocycled and uncoated), the fungal colonization appeared to depend upon the type of commercial resilient liner used. Thus, the lowest colonization was observed with fluoric and heat-cured silicone materials, cold-cured silicone materials, except for one product, and heat-cured acrylic resin exhibited the highest colonization capacity, and cold-cured acrylic resilient liners exhibited the intermediate. However, the fungal colonization on the materials was significantly promoted both by thermal cycling (ANOVA, P<0.01) and a layer of protein coating (saliva, P<0.01; serum, P<0.01). These results, taken together, suggest that the ageing of the materials and the biological fluids of the host promote yeast colonization on resilient lining materials.

The role of membrane potential and calcium kinetic changes in the pathogenesis of vascular hyporeactivity during severe shock

OBJECTIVE

To determine the role of membrane potential and intracellular calcium kinetic changes in producing vascular hyporeactivity during severe hemorrhagic shock.

METHODS

Rats were subjected to hemorrhagic shock (HS) for 2 hours. The spinotrapezius muscle was prepared for microscopy and the responses of arterioles in the muscle to norepinephrine (NE) were tested. The resting membrane potentials of isolated arterial strips were measured with a microelectrode. Membrane potential and intracellular Ca2+ ([Ca2+]i) changes in isolated arteriolar smooth muscle cells (ASMCs) were determined with fluorescent probes and a confocal microscopy.

RESULTS

The arteriolar resting membrane potential was decreased from -36.7 +/- 6.3 mV in control to -29.2 +/- 5.3 mV concurrent with the increase of vasoreactivity to NE at 20 minutes after HS. At 120 minutes post-HS, the resting potential hyperpolarized to -51.9 +/- 9.1 mV, and NE stimulated [Ca2+]i increase was reduced to 50% of the control values during the appearance of arteriolar hyporeactivity, i.e. the NE threshold of the arteriolar response increased 15 fold 2 hours after the onset of hemorrhage as compared with normal animals. The state of vasoreactivity was closely related to the resting potential of vascular smooth muscle in hemorrhagic shock, with a correlation coefficient of 0.96. Treatment with glybenclamide, a selective blocker of ATP-sensitive K+ (KATP) channels, decreased the resting potential, increased NE-stimulated [Ca2+]i increase, and partially restored vasoreactivity in severe hemorrhagic shock.

CONCLUSION

The results suggested that membrane hyperpolarization and the reduction of NE-stimulated [Ca2+]i increase in smooth muscle cells appeared to contribute to the vascular hyporeactivity in hemorrhagic shock. The mechanism is likely to involve in KATP channels.

Interactions between thermal cycled resilient denture lining materials, salivary and serum pellicles and Candida albicans in vitro. Part I. Effects on fungal growth

In the present study, the growth of a single isolate of Candida albicans on seven saliva-, serum-coated or protein free (uncoated), thermocycled (4-70 degrees C for 1 min, respectively; 0, 1000 and 10 000 times) commercial resilient lining materials was investigated by monitoring pH changes in growth media. The inhibitory effect of the tissue conditioners on fungal growth was observed using three parameters, i.e. (i) the delay in the onset of the rapid decline in pH, (ii) the reduction in the rate of pH change and (iii) the pH minima reached. In the case of control soft liners (not thermocycled and uncoated), the antifungal effect appeared to depend upon the type of commercial soft liner used. Thus, an initial delay in pH decline and a very high pH minima were observed with fluoric and heat-cured silicone materials. High pH minima were also observed with cold-cured acrylic soft liners, whereas cold-cured silicone materials did not significantly differ from heat-cured acrylic resin (P>0.05). However, the antifungal effect of the materials was significantly reduced both by thermal cycling (ANOVA, P<0.01) and a layer of protein coating (saliva, P<0.05; serum, P<0.01). These results, taken together, suggest that the ageing of the materials and the biological fluids of the host, particularly serum, promote yeast growth on soft lining materials.

Nonrandom karyotypic features in squamous cell carcinomas of the skin

We report the finding of clonal chromosome abnormalities in 13 short-term cultured squamous cell carcinomas (SCCs) of the skin. Intratumor heterogeneity, in the form of cytogenetically related (subclones) or unrelated clones, was detected in six tumors. Whereas clones with complex karyotypic changes were found in 6 tumors, clones with simple anomalies were observed in 10 tumors, and sometimes these clones coexisted with highly abnormal clones. Rearrangement of chromosome 8, in the form of isochromosome i(8q) or whole arm translocation, was the most common aberration, found predominantly in complex clones. Another recurrent feature, i.e., the centromeric rearrangement of chromosome 1, as isochromosome i(1q) or i(1p), or whole arm translocations, was always part of a complex karyotype. Homogeneously staining regions were found in two cases, one with a highly complex karyotype and the other with a simple karyotype. In order to obtain an overall karyotypic picture in SCC of the skin, the cytogenetic findings in 10 SCCs reported earlier were reviewed. The chromosomes most commonly affected were, in decreasing order, chromosomes 1, 11, 8, 9, 5, 3, and 7. Chromosomal sites most frequently rearranged were almost all pericentromeric: they were 8q10-q11, 1p10-q12, 5p10-q11, 11p15, and 9p10-q10. Recurrent anomalies were i(1q), i(8q), i(5p), i(1p), i(9p), and i(9q). Among them, only i(8q) and i(9q) might be assumed to be early genetic events, considering the fact that they could occasionally be identified in simple clones. The most frequent losses included part of or the entire chromosomes 2, 4, 9, 11, 14, 18, and 21, arm 8p, and chromosomes X, Y, and 13. Overrepresentation most frequently involved 1q, chromosome 7, and 8q. The characteristic karyotypic pattern observed in skin SCC was in line with the experience in several other carcinomas. Genes Chromosomes Cancer 26:295-303, 1999.

Low convulsive activity of a new carbapenem antibiotic, DK-35C, as compared with existing congeners

Since carbapenems and cephalosporins have been suggested to induce convulsive side effects through an inhibitory action on the central gamma-aminobutyric acid (GABA)-mediated inhibitory transmission, the present study evaluated the convulsive activity of a new carbapenem antibiotic (1R,5S,6S)-6[(R)-1-hydroxyethyl]-2-[(3S,5S)-5(S-methyl-4thiomorpholin ylcarbonyl)pyrrolidin-3-thio]-l-methylcarbapen-2-em-3- carboxylic acid (DK-35C) in in vitro and in vivo experiments, in comparison with cefazolin, imipenem and meropenem. In in vitro experiments, their abilities to inhibit [3H]muscimol (5 nM) binding to GABA(A) receptors were measured using crude synaptic membranes prepared from the rat cerebral cortex. The concentrations (mM) of the antibiotics which inhibit 50% of the specific binding, were 0.6 for imipenem, 1.8 for cefazolin, 15.4 for DK-35C and 27.6 for meropenem. In in vivo experiments, intracerebroventricular (i.c.v.) injections of cefazolin, imipenem and DK-35C induced convulsions in a dose-dependent manner in rats. The doses (nmol/rat) of the antibiotics which induce convulsions in 50% of rats, were 57 for imipenem, 96 for cefazolin, 377 for DK-35C and >3000 for meropenem. In the mouse pentylenetetrazole (PTZ) convulsive model, intravenous pretreatment with cefazolin (800 mg/kg) or imipenem (200 mg/kg) shifted the dose-response curve of PTZ (i.p.) to the left, indicating enhancement of the convulsive activity of PTZ. However, pretreatment with cefazolin, meropenem or DK-35C at a dose of 400 mg/kg did not produce any marked effects on the convulsive activity of PTZ compared with the saline vehicle-pretreated control. The results clearly demonstrate a good correlation between in vitro GABA(A) receptor binding assay and in vivo i.c.v. convulsive model using rats, and suggest that DK-35C may possess a relatively weak convulsive activity mediated through an interaction with GABA(A) receptors.

Binding affinities of 3-(3-phenylisoxazol-5-yl)methylidene-1-azabicycles to acetylcholine receptors

A series of 3-(3-phenylisoxazol-5-yl)methylidene-1-azabicycles synthesized showed different binding characteristics to acetylcholine receptors depending on the substituents on the phenyl ring. Small polar substituents gave preferential binding affinity to nicotinic receptors, and large hydrophobic substituents to muscarinic receptors.

Human localisation of band-pass filtered noise

In this work we study the influence and relationship of five different acoustical cues to the human sound localisation process. These cues are: interaural time delay, interaural level difference, interaural spectrum, monaural spectrum, and band-edge spectral contrast. Of particular interest was the synthesis and integration of the different cues to produce a coherent and robust percept of spatial location. The relative weighting and role of the different cues was investigated using band-pass filtered white noise with a frequency range (in kHz) of: 0.3-5, 0.3-7, 0.3-10, 0.3-14, 3-8, 4-9, and 7-14. These stimuli provided varying amounts of spectral information and physiologically detectable temporal information, thus probing the localisation process under varying sound conditions. Three subjects with normal hearing in both ears have performed five trials of 76 test positions for each of these stimuli in an anechoic room. All subjects showed systematic mislocalisation on most of these stimuli. The location to which they are mislocalised varies among subjects but in a systematic manner related to the five different acoustical cues. These cues have been correlated with the subject's localisation responses on an individual basis with the results suggesting that the internal weighting of the spectral cues may vary with the sound condition.

Molecular cloning and expression of Galbeta1,3GalNAc alpha2, 3-sialyltransferase from human fetal liver

Based on the sequences of the highly conserved segments in the previously cloned sialyltransferases, a cDNA encoding Galbeta1, 3GalNAc alpha2,3-sialyltransferase (SIATFL) has been isolated from human fetal liver. Expression analysis of the gene has been performed with various carcinoma cell lines, fetal tissues, fetal and adult liver and both hepatoma and the surrounding tissue from the same liver. The SIATFL gene was expressed poorly in fetal liver and in adult liver, slightly in hepatoma and highly in the surrounding tissue of hepatoma. The cDNA encoding the putative active domain was expressed in COS-1, Escherichia coli, and Pichia pastoris. The recombinant protein expressed in COS-1 could catalyse the transfer of NeuAc from CMP-NeuAc to asialo-fetuin. No enzyme activity was detected with a 32-kDa protein in E. coli and both 32-kDa and 41-kDa proteins in P. pastoris. These results suggested that correct glycosylation of the enzyme might play a key role in its folding that may be directly related to the enzymatic activity.