[Molecular cytogenetic study on four human esophageal cancer cell lines]

OBJECTIVE

To investigate the possible involvement of chromosome abnormalities in pathogenesis of human esophageal cancer.

METHODS

Four cell lines of human esophageal cancer (EC) established in our laboratory were analysed using interphase fluorescence in situ hybridization (FISH), chromosome painting technique and comparative genomic hybridization (CGH).

RESULTS

Chromosome gain of 1,2,3,8,16, 17, and 20 was found in the four cell lines, and loss of chromosome Y in cell line EC8712, EC8733 and EC8501 was noted. Other frequent changes were partial deletion of 1p, translocation of 2q and amplification of 5p in all 4 cell lines, and amplification of 8q and 13q in EC8733 and deletion of 17p in EC8712.

CONCLUSION

The data suggest that nonrandom chromosome aberrations may play an important role in the pathogenesis of human esophageal cancer.

Supercomputer description of human lung morphology for imaging analysis

A supercomputer code that describes the three-dimensional branching structure of the human lung has been developed. The algorithm was written for the Cray C94. In our simulations, the human lung was divided into a matrix containing discrete volumes (voxels) so as to be compatible with analyses of SPECT images. The matrix has 3840 voxels. The matrix can be segmented into transverse, sagittal and coronal layers analogous to human subject examinations. The compositions of individual voxels were identified by the type and respective number of airways present. The code provides a mapping of the spatial positions of the almost 17 million airways in human lungs and unambiguously assigns each airway to a voxel. Thus, the clinician and research scientist in the medical arena have a powerful new tool to be used in imaging analyses. The code was designed to be integrated into diverse applications, including the interpretation of SPECT images, the design of inhalation exposure experiments and the targeted delivery of inhaled pharmacologic drugs.

Cytochrome P450-dependent desaturation of lauric acid: isoform selectivity and mechanism of formation of 11-dodecenoic acid

Cytochrome P450-catalyzed desaturation reactions have been reported infrequently in the literature. Previously, we documented the formation of the terminal olefinic metabolite of valproic acid by various members of the CYP2B and CYP4B sub-families. However, despite the extensive use of fatty acid substrates in drug metabolism studies, other examples of terminal desaturation at non-activated carbon centers are lacking. The goals of the present studies were to determine whether the archetypal P450 substrate, lauric acid (dodecanoic acid; DDA), also undergoes desaturation reactions, identify specific rabbit P450 isoforms which catalyze this reaction and examine its mechanism. A highly sensitive, capillary GC/MS assay was developed to separate and quantitate the trimethylsilyl derivatives of 11-ene-DDA, cis- and trans-10-ene-DDA and cis- and trans-9-ene-DDA. Among all of these potential olefinic metabolites, only 11-ene-DDA was formed at a significant rate by rabbit liver microsomes. The formation of 11-ene-DDA was NADPH-dependent, and was induced markedly by acetone pre-treatment, but not by phenobarbital, rifampin or Arochlor 1254. Studies with seven purified, reconstituted rabbit P450 isoforms showed that the most rapid rates of desaturation were obtained with CYP2E1, CYP4A5/7 and CYP4B1. Non-competitive, intermolecular isotope effect experiments, conducted with [12,12,12-2H3]DDA and [11,11-2H2]DDA, demonstrated further that CYP4B1-mediated terminal desaturation of DDA is initiated by removal of a hydrogen atom from the omega-1 rather than the omega position.

[Detection and sequence analysis of the p53 gene mutation in epithelial ovarian cancer]

OBJECTIVE

To find the characteristics of p53 gene mutation in epithelial ovarian cancer and to analyze the relationship between p53 mutation and FIGO stage.

METHODS

p53 mutations in exon 5 to 7 were detected by single-strand conformational polymorphism (SSCP) and sequencing technique.

RESULTS

8 of 46 tumor tissues demonstrated a SSCP band shift in the region of the gene. All of them have been characterized to represent DNA alterations by sequencing, including 8 point mutations (6 missence, 1 silent mutation and 1 in intron) and a 1-base pair insertion (introducing a stop codon downstream). Overall, 88.9% of mutation were transitions, and most of them are G-->A transitions (7/8, 87.5%). 62.5% of the mutation were found in 175 and 245 codon. The percentage of the mutation in stage I and stage II was 20.0%, and in stage III and stage IV was 16.7% (P > 0.05).

CONCLUSION

The arising of p53 mutations in ovarian cancer is due to spontaneous error in DNA synthesis and repair. Codon 175, 245 are the two mutational hot spots. There is no relationship between the mutation of p53 gene and FIGO stage in epithelial ovarian cancer.

[Antivirus effect of polysaccharides of brewer yeast in vitro]

The antivirus effect of polysaccharides of brewer yeast from yeast mud on 13 kinds of viruses including DNA and RNA virus along with their mechanisms were studied. The result showed that this effect was remarkable on the infections with poliovirus III, adenovirus III, ECHO6 virus, enterovirus 71, vesicular stomatitis virus, herpesvirus I, II, coxsackie A16 virus and coxsackie B3 virus. The polysaccharides of brewer yeast could also inhibit the development of cytopathic effect(CPE) and protect cultural cells from being infected with the above viruses.

Experimental studies of electroacupuncture on ventricular fibrillation threshold in rats with acute ischemic myocardium

By ligating the proximate left anterior descend (LAD) of coronary artery and inducing the ventricular fibrillation with electrical stimulation, the preventive effects of electroacupuncture (EA) on ventricular fibrillation were observed. The results showed that the ventricular fibrillation threshold (VFT) of rats with acute ischemic myocardium was raised after acupuncturing some acupoints, which could prevent the occurrence of ventricular fibrillation. Furthermore, the combination of EA and propranolol could enhance the VFT effectively, and they showed a good synergistic effect.

The sleep-inducing lipid oleamide deconvolutes gap junction communication and calcium wave transmission in glial cells

Oleamide is a sleep-inducing lipid originally isolated from the cerebrospinal fluid of sleep-deprived cats. Oleamide was found to potently and selectively inactivate gap junction-mediated communication between rat glial cells. In contrast, oleamide had no effect on mechanically stimulated calcium wave transmission in this same cell type. Other chemical compounds traditionally used as inhibitors of gap junctional communication, like heptanol and 18beta-glycyrrhetinic acid, blocked not only gap junctional communication but also intercellular calcium signaling. Given the central role for intercellular small molecule and electrical signaling in central nervous system function, oleamide- induced inactivation of glial cell gap junction channels may serve to regulate communication between brain cells, and in doing so, may influence higher order neuronal events like sleep induction.

Formation of circular satellite tobacco ringspot virus RNA in protoplasts transiently expressing the linear RNA

The most abundant form of the satellite RNA of tobacco ringspot virus (sTRSV RNA) is a linear, unit length molecule of 359 nucleotide residues, designated L-(+)M. A postulated replication scheme for the satellite RNA has as its first, and apparently virus-independent, step the ligation of L-(+)M into the corresponding circular form C-(+)M. We transiently expressed L-(+)M wild type and L-(+)M mutants in tobacco protoplasts using an African cassava mosaic geminivirus vector. Measured extents of C-(+)M accumulation were correlated with computer-predicted folding to suggest wild-type secondary structure elements that might be deleted without reducing ligation. A 127-nucleotide residue mutant L-(+)M was created by replacing, with 7 and 3 residues, respectively, nucleotide residues 53-211 and 268-350, each of which was predicted to form a set of three adjacent imperfect stem-loops in wild-type L-(+)M. The mutant L-(+)M was found to be extensively ligated to C-(+)M in protoplasts and to retain a calculated helix of the wild-type molecule that incorporates the 3' terminal sequence. A trinucleotide in the 3' region was mutated so as to disrupt and restore, respectively, the calculated helix, reducing and restoring, respectively, C-(+)M formation. These results suggest that the 3' stem contributes to the suitability of the small L-(+)M molecules as a substrate for a protoplast RNA ligase and that computed folding of sTRSV RNA may be predictive of sTRSV RNA structure in vivo.

[Electroacupuncture along meridians activating subcutaneous primary afferents in acupoints--CB-HRP tracing study]

The experiment was performed to observe the segmental distribution of sensory afferent nerves in acupoints and the influence of electroacupuncture (EA) along meridians on it. 1% CB-HRP solution (5 microliters) was injected subcutaneously at unilateral "Zusanli" or "Ruzhong" acupoint of rats. The HRP labeled cells were counted in the related spinal dorsal root ganglia (DRG). The results were as follows: the sensory nerve terminals of "Zusanli" acupoint mainly projected to the neurons of L4 and L5 DRG and that of "Ruzhong" acupoint projected to the neurons of T4, T5 and T6 DRG; sensory nerve terminals of "Zusanli" or "Ruzhong" acupoint were activated by the EA stimulation along meridians, their ability of uptaking HRP was enhanced, so the HRP labeled cells increased in the related DRG, the HRP labeled DRG segments spread. This study provides a new morphological evidence for the mechanism's explanation of propagated sensation along the meridians.

[The relationship of C fiber to 5-hydroxytryptamine in spinal cord of rat in electroacupuncture analgesia]

By using spectrofluorophotometry, it was observed that electroacupuntrure at "Huantiao" points of rat could decease the content of 5-hydroxytryptamine (5-HT) and increase the content of 5-hydroxyindoleacetic acid (5-HIAA) in spinal cord. However, the above effects of electroacupunture were obviously reduced after the C fibers of rats had been destroyed by capsaicin, which suggesting that capsaicin-sensitive C fiber might take part in the roles of electroacupuncture's promoting the release and utilization of 5-HT in spinal cord.

[Segmental influence of dorsal root action potentials evoked by stimulating the acupoints after acupuncture along meridians]

Using the method of recording the corresponding dorsal root action potentials evoked by stimulating the acupoints, we found that electro-acupuncture could not only expand the segmental of potentials, but also amplitude the potentials. The results proved the acupuncture sensation may be transsegmental afferent after acupuncture along the meridians. This study gave a new evidence for the mechanism's explanation of propagated sensation along the meridians.

[The influence of electroacupuncture on the mast cells in the acupoints of the stomach meridian]

Giving electroacupuncture at unilateral "Biguan" and "Zusanli" points, we observed the rat subcutaneous mast cells of "Tianshu", "Biguan", "Futu", "Zusanli" and "Xiajuxu" acupoints in bilateral Stamach Meridian. It was found that the numbers of mast cells in all the acupoints studied were higher than that in the non acupoint area. The numbers of mast cell in acupoints were increased under electroacupuncture, while that in non acupoint area was not changed. The results suggested the mast cells play an important role in the functions of the Meridian.

[Influence of electroacupuncture and capsaicin treatment on AChE activity and [3H]-QNB binding sites in the spinal dorsal horn]

1.5% Capsaicin (Cap) or Vehicle was respectively used to treat the right or left sciatic nerve in 20 Sprague-Dawley rats. On the seventh day, the 20 rats were at random divided into electroacupuncture (EA) group and non-EA group, the spinal cord corresponding to the afferent segments of sciatic nerve was taken out for observing the changes of acetylcholinesterase (AChE) activity and [3H]-quinuelidinylbenzylate (QNB) binding sites in the spinal dorsal horn (SDH). The results were as follows: (1) EA "Huantiao" could enhance AChE activity in the SDH and decrease [3H]-QNB binding sites; (2) Cap treating sciatice nerve could weaken AChE activity in the SDH and merease [3H]-QNB binding sites; (3) Cap treatment could inhibit or partially inhibit the actions of EA as above. The results indicated that ACh participated in the primary afferent of acupuncture information and might exist in Cap-sensitive neurons.

[Effects of electroacupuncture on the subcutaneous mast cells of zusanli acupoint in rat with unilateral sciatic nerve transection]

Electroacupuncture could induce the convergence and degranulation of subcutaneous mast cells in acupoints. After unilateral transection of sciatic nerve, we studied the numbers of subcutaneous mast cells and its degranulation in bilateral Zusanli and Xiajuxu acupoints with electroacupuncture in Zusanli. We found that sciatic nerve transection could reduce the total numbers of mast cells and the degranulation numbers of mast cells in Zusanli. The results suggested peripheral nerves play an important role in the convergence and degranulation of mast cells in acupoints by electroacupuncture induction.

Domain identification by clustering sequence alignments

A sequence databases are growing rapidly, results from sequence comparison searches using fast search methods such as BLAST and FASTA tend to be long and difficult to digest. In this paper, we present a new method to extract domain information from sequence comparison searches by clustering the resulting alignments according to their similarity to the query sequence. Efficient tree structures and algorithms are used to organize the alignment data such that structurally conserved elements can be easily identified. The hierarchical nature of the data structures used and the flexible X-Window based interface provide an efficient and intuitive means to explore the alignment data at different levels so the main domains as well as distantly related features can be explored.

Computer simulations of lung morphologies within planar gamma camera images

A mathematical model and computer code have been developed to unambiguously interpret planar gamma camera images. Specifically, the algorithm permits airway composition of the central, intermediate and peripheral partitions of scans to be determined quantitatively. The algorithm unambigously identifies the spatial coordinates of each of the millions of airways within the adult human lung, and assigns every individual airway to a precise location within the gamma camera image format prescribed by the clinician. This is done on a patient-by-patient basis. The algorithm has evolved from clinical applications of the previous work of Martonen et al. [1]. The objective of the current work was to advance the original protocol and derive an algorithm that was: (1) from a medical perspective, more physiologically realistic; and (2) from a technical perspective, easier to apply in the medical arena. Regarding (1), the major elements of the algorithm are that the outer boundary of the lung is formulated directly from lung perfusion imaging data and that the lung is divided into distinct left and right components. Regarding (2), the algorithm has been written for use with common workstations. It is our hope that the improvements will facilitate applications of the new model-code into aerosol therapy regimens.

Steroidogenic factor-1 is an essential transcriptional activator for gonad-specific expression of promoter I of the rat prolactin receptor gene

The expression of the prolactin receptor is under the control of two putative tissue-specific (PI, gonads; PII, liver) and one common (PIII) promoters (Hu, Z. Z., Zhuang, L., and Dufau, M. L. (1996) J. Biol. Chem. 271, 10242-10246). The three promoter regions were co-localized to the rat chromosomal locus 2ql6, in the order 5'-PIII-PI-PII-3'. To investigate the mechanisms of gonad-specific utilization of PI, the promoter domain, regulatory cis-elements, and trans-factors were identified in gonadal cells. The promoter domain localized to the 152-base pair 5' of the transcriptional start site at -549 is highly active in gonadal cells but has minimal activity in hepatoma cells. It contains a steroidogenic factor 1 (SF-1) element (-668) that binds the SF-1 protein of nuclear extracts from gonadal cells and is essential for promoter activation. A CCAAT box (-623) contributes minimally to basal activity in the absence of the SF-1 element, and two adjacent TATA-like sequences act as inhibitory elements. Thus, PI belongs to a class of TATA-less/non-initiator gene promoters. These findings demonstrate an essential role for SF-1 in transcriptional activation of promoter I of the prolactin receptor gene, which may explain the tissue-specific expression of PI in the gonads but not in the liver and the mammary gland.

Effects of propranolol on beta-adrenergic receptor of experimental acute myocardial infarction in rats

By using receptor autoradiography to observe the distribution and density of receptors, the effects of propranolol, a beta-blocker, on beta-adrenergic receptor of experimental acute myocardial infarction (AMI) were studied. One week after ligation of proximate left anterior descend (LAD) coronary artery, [3H] DHA binding sites were markedly decreased in both infarct region and non-infarct region. After treatment of propranolol (100 micrograms/kg), the [3H] DHA binding sites were obviously increased in the infarct region, and they were further decreased in the non-infarct region. The ratio of [3H] DHA binding sites of the infarct region to non-infarct region was from 0.24 at LAD ligation to 0.87 after propranolol treatment, which was close to 0.97 of control group (sham operation). The results indicated that the propranolol acted directly on myocardial beta- adrenergic through the receptor regulation of the balance of beta-receptors between the infarct region and non-infarct region, and improvement of the myocardial consonation and contraction synergism, thereby protecting the heart affected by AMI.

Localization and function of the connexin 43 gap-junction protein in normal and various oncogene-expressing rat liver epithelial cells

Clones of rat liver epithelial cells genotypically altered by mutation or by a variety of oncogenes were analyzed by microinjection-dye transfer, immunofluorescence confocal microscopy, and western blotting to determine at what level and to what degree these transformations disrupted gap-junctional intercellular communication (GJIC) mediated by connexin 43 (Cx43). Compared with normal rat liver epithelial cells, cells neoplastically transformed by src, neu, ras, and myc/ras all displayed reduced degrees of GJIC, reduced levels of membrane-associated Cx43 plaques, and hypophosphorylation of Cx43. Confocal analysis further demonstrated that the Cx43 protein was localized, at least in part, to the nucleus rather than to the plasma membrane in the src- and neu-transformed cells, but not in the ras- and myc/ras-transformed cells. Nuclei isolated from WB-neu cells showed substantially higher levels of Cx43 on western blotting than did nuclei from WB-neo control cells, supporting the idea that the nuclear-localized immunopositive material detected by confocal microscopy was Cx43 protein. In a GJIC-deficient mutant rat liver epithelial cell line containing normal numbers of plasma membrane-localized Cx43 plaques that appeared to be reduced in size, the Cx43 protein was also found to be hypophosphorylated. Cells overexpressing myc, on the other hand, displayed a normal degree of GJIC, increased levels of plasma membrane-localized Cx43 plaques, and hyperphosphorylation of the Cx43 protein. Cells expressing raf, previously shown to be GJIC competent, showed Cx43 immunostaining patterns similar to those in normal cells, whereas a cell line established from a tumor induced by injection of these raf-expressing cells into a mouse showed a marked reduction in GJIC and plasma membrane-associated Cx43 immunostaining. These data suggest that altered localization of the gap-junction protein Cx43, mediated in part by changes in the phosphorylation of this protein, contributes to the disruption of GJIC in neoplastically transformed rat liver epithelial cells.

Gap junction endocytosis and lysosomal degradation of connexin43-P2 in WB-F344 rat liver epithelial cells treated with DDT and lindane

Treatment of WB-F344 rat liver epithelial cells with DDT (1,1-bis(p-chlorophenyl)-2,2,2-trichloroethane) or lindane induces a loss of gap junction plaques and a decrease in the phosphorylated gap junction protein connexin43-P2 (Cx43-P2), which is associated with the plaques. In this study we have considered several mechanisms. The loss of junctional plaques could be due to disaggregation of junctional particles or to endocytosis of the plaques, while the loss of Cx43-P2 could be due to dephosphorylation or degradation. Immunohistochemical analyses of DDT- or lindane-treated cells revealed a reduction in plasma membranous Cx43-positive gap junction plaques coincident with the appearance of Cx43-positive punctate cytoplasmic structures. The cytoplasmic Cx43-positive structures eventually disappeared after 4 h treatment. Diffuse Cx43-positive plasma membranous staining was not seen following DDT or lindane treatment. Western blot analyses of these cells indicated that Cx43-P2 decreased in a time-dependent manner that paralleled the disappearance of gap junction plaques from the plasma membrane. The loss of Cx43-P2 was not due to dephosphorylation, since no increase in non-phosphorylated (Cx43-NP) or other phosphorylated (Cx43-P1) forms of the protein were evident. The decrease in Cx43-P2 and the disappearance of cytoplasmic Cx43-positive structures were prevented by colchicine and chloroquine, which suggests that Cx43-P2-containing plaques were internalized and degraded in lysosomes. In addition, two small (approximately 18 and approximately 22 kDa) bands appeared in Western blots coincident with the loss of Cx43-P2 and may be degradation products of the protein. These immunohistochemical and biochemical data strongly suggest that the loss of gap junction plaques and of Cx43-P2 in WB-F344 cells treated with DDT and lindane were due to endocytosis of the plaques and degradation of Cx43-P2 in lysosomes.

Collaborative study on evaluation of immunodiagnostic assays in schistosomiasis japonica by treatment efficacy assessment. Collaboration Group

OBJECTIVE

This paper is the summary of "National Symposium on the Value of Immunodiagnostic Assays in Schistosomiasis by Treatment Effects Assessment" which was directed by the Expert Advisory Committee for Schistosomiasis of the Ministry of Public Health. This symposium was held to evaluate the diagnostic effects of the new system of detection in the sensitivity and specificity by treatment assessment.

MATERIALS AND METHODS

Twelve laboratories with 14 assay systems participated in this collaborative study, in which, 450 sera were detected by double blind trial using a classical antibody detection with ELISA as a control.

RESULTS

The results showed that 6 test systems were superior or close to the classical antibody detection, especially in evaluating the value of treatment effects.

CONCLUSIONS

It is unanimously recognized that much progress has been made in the research of immunodiagnosis of schistosomiasis in China, but many problems remain to be solved and worth further studying.

Localization and function of the connexin 43 gap-junction protein in normal and various oncogene-expressing rat liver epithelial cells

Clones of rat liver epithelial cells genotypically altered by mutation or by a variety of oncogenes were analyzed by microinjection-dye transfer, immunofluorescence confocal microscopy, and western blotting to determine at what level and to what degree these transformations disrupted gap-junctional intercellular communication (GJIC) mediated by connexin 43 (Cx43). Compared with normal rat liver epithelial cells, cells neoplastically transformed by src, neu, ras, and myc/ras all displayed reduced degrees of GJIC, reduced levels of membrane-associated Cx43 plaques, and hypophosphorylation of Cx43. Confocal analysis further demonstrated that the Cx43 protein was localized, at least in part, to the nucleus rather than to the plasma membrane in the src- and neu-transformed cells, but not in the ras- and myc/ras-transformed cells. Nuclei isolated from WB-neu cells showed substantially higher levels of Cx43 on western blotting than did nuclei from WB-neo control cells, supporting the idea that the nuclear-localized immunopositive material detected by confocal microscopy was Cx43 protein. In a GJIC-deficient mutant rat liver epithelial cell line containing normal numbers of plasma membrane-localized Cx43 plaques that appeared to be reduced in size, the Cx43 protein was also found to be hypophosphorylated. Cells overexpressing myc, on the other hand, displayed a normal degree of GJIC, increased levels of plasma membrane-localized Cx43 plaques, and hyperphosphorylation of the Cx43 protein. Cells expressing raf, previously shown to be GJIC competent, showed Cx43 immunostaining patterns similar to those in normal cells, whereas a cell line established from a tumor induced by injection of these raf-expressing cells into a mouse showed a marked reduction in GJIC and plasma membrane-associated Cx43 immunostaining. These data suggest that altered localization of the gap-junction protein Cx43, mediated in part by changes in the phosphorylation of this protein, contributes to the disruption of GJIC in neoplastically transformed rat liver epithelial cells.

Gap-junction disassembly and connexin 43 dephosphorylation induced by 18 beta-glycyrrhetinic acid

Gap-junction channels connect the interiors of adjacent cells and can be arranged into aggregates or plaques consisting of hundreds to thousands of channel particles. The mechanism of channel aggregation into plaques and whether plaques can disaggregate are not known. Many carcinogenic and tumor-promoting chemicals have been identified that inhibit cell-cell gap-junctional coupling. Here, we provide morphological evidence that 18 beta-glycyrrhetinic acid (18 beta-GA), a saponin isolated from licorice root that is an inhibitor of gap-junctional communication, caused the disassembly of gap-junction plaques in WB-F344 rat liver epithelial cells. This effect was dose (5-40 microM) and time dependent (1-4 h treatment). Gap-junction channels in WB-F344 cells are comprised of connexin 43 (Cx43), and the protein is phosphorylated to a species known as Cx43-P2 coincident with the assembly of channels into plaques. Consistent with this, the disassembly of plaques induced by 18 beta-GA was correlated with decreases in Cx43-P2 levels and increases in nonphosphorylated Cx43. Biochemical evidence indicated that these changes in the P2 and NP forms of Cx43 represented 18 beta-GA-induced dephosphorylation of Cx43-P2 and not its degradation or the inhibition of Cx43-NP phosphorylation. Okadaic acid and calyculin A, which are inhibitors of type 1 and type 2A protein phosphatases, prevented the dephosphorylation of Cx43, suggesting that one or both of these phosphatases were involved in Cx43 dephosphorylation. These data indicate that 18 beta-GA causes type 1 or type 2A protein phosphatase-mediated Cx43 dephosphorylation coincident with the disassembly of gap-junction plaques.

[Antimicrobial properties of Flos Lonicerae against oral pathogens]

The antimicrobial effect of Flos Lonicerae on oral pathogens was studied. The results showed that 73.9% of the tested pathogens were inhibited at a concentration below 6.25mg/ml. Streptococci mutants, actinomyces viscosus and bacteroides melaninogenicus were comparatively more sensitive to Flos Lonicerae.

Identification of three new microsatellite markers in the spinocerebellar ataxia type 2 (SCA2) region and 1.2 Mb physical map

Spinocerebellar ataxia type 2 (SCA2) is a neurodegenerative disease recently mapped to chromosome 12q close to the locus D12S84 by genetic linkage analysis. To generate additional genetic markers in the SCA2 region, we constructed a physical map of the region using yeast artificial chomosome (YAC), P1 artificial chromosome (PAC) and cosmid clones. The physical map was found to agree well with the genetic map. Three novel microsatellite markers were isolated and physically mapped. A novel approach to isolate CAG repeats directly from YAC DNAs is described.

[The selection of highly lung metastatic salivary adenoid cystic carcinoma clone]

After 5 times repeated selection in vivo, combined with cloning technique in vitro and analysing of platelet aggregation activity, we had selected a highly lung metastatic salivary adenoid cystic carcinoma clone M-5clone24 (Acc-M). Compared with Acc-2, its metastatic rate was 96% vs. 18%; the weight of metastatic lung was 0.88 g vs. 0.31 g. The metastatic rate and the weight of metastatic lung positively correlated with platelet aggregation activity. The aggregation activity might be used as a useful parameter to assess Acc metastasis potential.

Detection of RNA polymerase II promoters and polyadenylation sites in human DNA sequence

Detection of RNA polymerase II promoters and polyadenylation sites helps to locate gene boundaries and can enhance accurate gene recognition and modeling in genomic DNA sequence. We describe a system which can be used to detect polyadenylation sites and thus delineate the 3' boundary of a gene, and discuss improvements to a system first described in Matis et al. (1995) [Matis S., Shah M., Mural R. J. & Uberbacher E.C. (1995) Proc. First Wrld Conf. Computat. Med., Public Hlth, Biotechnol. (Wrld Sci.) (in press).], which predicts a large subset of RNA polymerase II promoters. The promoter system used statistical matrices and distance information as inputs for a neural network which was trained to provide initial promoter recognition. The output of the network was further refined by applying rules which use the gene context information predicted by GRAIL. We have reconstructed the rule-based system which uses gene context information and significantly improved the sensitivity and selectivity of promoter detection.

Alignments of DNA and protein sequences containing frameshift errors

Molecular sequences, like all experimental data, are subject to error. Many current DNA sequencing protocols have very significant error rates and often generate artefactual insertions and deletions of bases (indels) which corrupt the translation of sequences and compromise the detection of protein homologies. The impact of these errors on the utility of molecular sequence data is dependent on the analytic technique used to interpret the data. In the presence of frameshift errors, standard algorithms using six-frame translation can miss important homologies because only subfragments of the correct translation are available in any given frame. We present a new algorithm which can detect and correct frameshift errors in DNA sequences during comparison of translated sequences with protein sequences in the databases. This algorithm can recognize homologous proteins sharing 30% identity even in the presence of a 7% frameshift error rate. Our algorithm uses dynamic programming, producing a guaranteed optimal alignment in the presence of frameshifts, and has a sensitivity equivalent to Smith-Waterman. The computational efficiency of the algorithm is O(nm) where n and m are the sizes of two sequences being compared. The algorithm does not rely on prior knowledge or heuristic rules and performs significantly better than any previously reported method.

Reduction of growth and acetyl-CoA carboxylase activity by expression of a chimeric streptavidin gene in Escherichia coli

The streptavidin gene from Streptomyces avidinii was expressed in E. coli as a non-fusion protein and as a glutathione S-transferase fusion protein. The streptavidin protein accumulated primarily in the inclusion bodies and did not alter cell growth. In contrast, the glutathione-S-transferase-streptavidin fusion protein was soluble. Nondenaturing polyacrylamide gel electrophoresis indicated that the chimeric glutathione-S-transferase-streptavidin protein was present mostly as a monomer, with some detectable polymeric forms. Cells grown in the presence of [3H]-biotin had label specifically associated with the expressed glutathione-S-transferase-streptavidin fusion protein, indicating this protein bound biotin in vivo. The majority of the radiolabeled biotin was associated with polymeric forms of the glutathione-S-transferase-streptavidin protein. The growth rates of biotin auxotrophs of E. coli growing in biotin-deficient media were substantially decreased by the expression of the glutathione-S-transferase-streptavidin gene. The decreased growth rate correlated with a decrease in acetyl-CoA carboxylase activity.

Inhibition of gap junctional intercellular communication and enhancement of growth in BALB/c 3T3 cells treated with connexin43 antisense oligonucleotides

Many studies have correlated reductions in gap junctional intercellular communication (GJIC) with altered cellular growth, tumor promotion, and neoplastic transformation. To test directly whether reduced GJIC affects cellular growth, GJIC was inhibited in murine BALB/c 3T3 fibroblasts by treatment with a phosphorothioate-modified antisense oligonucleotide targeted against the connexin43 translation start codon, and in vitro cell growth was monitored. The cells were incubated with the oligonucleotide (0.1-0.5 microM) in liposomes in serumless culture medium for 16 h; washed and refed with serum-containing medium; and analyzed for dye-coupling, connexin43 protein and mRNA levels, and cell growth over the next 5 d. The antisense oligonucleotide inhibited dye-coupling and reduced connexin43 protein levels in a concentration-dependent manner but had no effect on connexin43 mRNA levels. Cell growth rate was not affected, but saturation density was increased approximately threefold by the oligonucleotide. These data support a role for GJIC in the establishment of contact inhibition of in vitro cell growth.

Isolation of YAC insert sequences by representational difference analysis

We present a method for the isolation of YAC insert sequences by representational difference analysis (RDA). To achieve maximal representation of the sequences, the amplicons were generated from a Mbol digestion product. RDA was performed using a 970 kb insert YAC clone. After two rounds of re-association and selective amplification 92% of the difference product represented sequences derived from the YAC insert. Twenty insert-specific sequence-tagged sites were readily defined. The difference product was also successfully used to isolate microsatellite markers, to identify clones from a human PAC library and as a chromosome painting probe in fluorescence in situ hybridization.

An integrated high-resolution physical map of the DPC/BRCA2 region at chromosome 13q12

We identified a homozygous deletion in a pancreatic carcinoma (DPC) that localized to a 1-cM region at chromosome 13q12.3, which lay within the 6-cM locus of familial breast cancer susceptibility (BRCA-2). Here we present a physical map of the region, consisting of YAC, PAC, and cosmid contigs. The YAC contig comprises 16 clones that together span the entire BRCA2 region. The PAC contig comprises 22 clones that together span the DPC region. Seventy cosmid clones were localized within and near the DPC region. Thirty-five sequence-tagged sites were defined and localized within the map. The map indicates the size of the DPC region to be near 250 kb, and provides mapped and cloned resources for the search for the putative tumor suppressor gene(s) in the region.

Down-regulation by butylated hydroxytoluene of the number and function of gap junctions in epithelial cell lines derived from mouse lung and rat liver

The mouse pneumotoxicant and lung and liver tumor promoter butylated hydroxytoluene (BHT) was examined for its effects on gap junctional intercellular communication (GJIC) in mouse lung epithelial (C10) and rat liver epithelial (WB-F344) cell lines. GJIC, as measured by fluorescent dye microinjection, was inhibited in both types of cells by BHT in dose- and time-dependent fashions. Inhibition was detected in WB-F344 cells at BHT concentrations > or = 62.5 microM and in C10 cells at concentrations > or = 150 microM after 4 h treatment. Inhibition occurred within 15-30 min and was reversed by removing BHT from the culture medium. The highly toxic BHT metabolite 6-t-butyl-2-(hydroxy-t-butyl)-4-methylphenol (BHTOH) and the non-toxic BHT metabolite, 2,6-di-t-butyl-4-hydroxymethylphenol (BHTBzOH) were also tested. In both cell lines BHTOH was a more potent inhibitor of GJIC than BHT, whereas BHTBzOH was ineffective. The mechanisms of inhibition of GJIC by BHT were also examined. The initial rapid inhibition detected within 15-30 min may have been due to gap junction channel closure or blockage, since no changes in gap junction number, connexin (Cx) 43 levels or Cx43 phosphorylation were observed. By 2-4 h, however, gap junctions were internalized into the cytoplasm, the number of immunodetectable plasma membrane gap junctions was reduced and phosphorylated Cx43-P2 was decreased. Treatment of the cells for 24 h with 12-O-tetradecanoylphorbol-13-acetate (TPA) prevented inhibition of GJIC by TPA, but not by BHT. Western blot analyses of TPA-treated WB-F344 or C10 cells revealed the presence of a hyperphosphorylated form of Cx43 (Cx43-P3) and no reduction in Cx43-P2, in contrast to BHT-treated cells. These data suggest that BHT and TPA inhibit lung and liver epithelial cell GJIC through distinct mechanisms.

Changes in gap junction permeability, gap junction number, and connexin43 expression in lindane-treated rat liver epithelial cells

The pesticide lindane (gamma-hexachlorocyclohexane) is a mammalian neurotoxin and hepatocarcinogen. Lindane can inhibit gap junctional intercellular communication (GJIC) and this effect may contribute to its toxic properties. The mechanism of inhibition of GJIC by lindane in WB-F344 rat liver epithelial cells was studied to determine if altered gap junction permeability, gap junction number, and/or gap junction protein (connexin43) expression were involved. GJIC was monitored by fluorescent Lucifer Yellow CH dye microinjection (dye-coupling). Gap junction number was quantified visually after indirect immunostaining of gap junctions using an anti-connexin43 monoclonal antibody. Connexin43 mRNA and protein levels were determined by Northern and Western blotting, respectively. Short-term treatment (10-30 min) with lindane (50 microM) resulted in the rapid (within 10 min), nearly complete loss of dye-coupling but no changes in gap junction number of connexin43 mRNA or protein levels. Medium-term treatment (1-4 hr) resulted in the loss of dye-coupling, gap junctions, and phosphorylated connexin43 proteins. Long-term treatment (1-14 days) led to reductions in dye-coupling, total connexin43 protein, and connexin43 mRNA. Nuclear run-on assays indicated that transcription of the connexin43 gene was reduced nonspecifically by lindane. These data indicate that reductions in gap junction permeability, number, and expression may be involved in the inhibition of GJIC depending on pesticide treatment duration.

Detection of chromosome 12q amplification in sarcomas by chromosome microdissection and interphase fish

We describe the microdissection of a homogeneously staining region (hsr) in the neuroblastoma cell line NGP-127 which contains the SAS gene. Fluorescence in situ hybridization (FISH) of this probe to NGP-127 cells confirms its derivation from the hsr, while FISH to normal chromosomes establishes that the hsr is composed of sequences from two segments of chromosome 12q. The hsr microdissection probe yields fluorescent signals which are sufficiently intense to readily identify amplification of homologous sequences in interphase nuclei.

Operational stabilization of a high-power ultrashort dye oscillator-amplifiers laser chain

Stable operation of a high-power ultrashort dye laser chain is achieved with an inexpensive heating technique. The femtosecond oscillator and its pumping laser are separately covered with boxes to isolate them from external temperature fluctuations. Both laser-isolating boxes are lined with a heating pellicle that permanently and uniformly warms the lasers to preset operating temperatures. The power, spectrum, and duration of the laser-chain output pulse remain constant from day to day. This technique could be applied to other ultrafast laser devices that require long-term performance stability.

Taurine conjugation of ibuprofen in humans and in rat liver in vitro. Relationship to metabolic chiral inversion

Following administration of a single oral dose (400 mg) or RS-ibuprofen (RS-IBP) to humans, a novel metabolite was isolated from urine and identified by tandem mass spectrometry as the taurine conjugate of IBP (IBP-Tau). The corresponding glycine conjugate was sought but was not detected in these studies. Quantitative analyses indicated that taurine conjugation represents a minor biotransformation pathway for IBP (1.52 +/- 0.43% of the dose over 24 h, n = 4), but it is nonetheless one of mechanistic significance in that it requires the prior formation of the coenzyme A thioester of IBP (IBP-CoA). The latter conjugate, which has not been detected in vivo because of its intracellular compartmentalization, plays a key role in the metabolic chiral inversion of R- to S-IBP. By means of stereoselective gas chromatography-mass spectrometry, it was found that IBP liberated from the urinary IBP-Tau under nonracemizing conditions consisted mainly (ca. 87%) of molecules of S configuration. From separate experiments with volunteers given a pseudoracemic mixture of the drug (R-IBP/S-[2H3]IBP), it was shown that the majority of the S-IBP-Tau was derived from S-IBP, rather than from R-IBP by way of chiral inversion. These findings, together with the results of in vitro experiments with rat liver mitochondrial preparations and isolated rat hepatocytes, demonstrate that although activation of IBP to its CoA thioester favors the R enantiomer over its antipode, S-IBP also participates in CoA-dependent reactions, including metabolic chiral inversion.

L-dopa reverses castration-induced disruption of dishabituation responses to female chemical cues in male rats

In the present experiment, habituation/dishabituation behavioral tests were conducted to measure discriminatory olfactory recognition responses to chemical cues among control, castrated, and castrated+L-3,4-dihydroxyphenylalanine (L-DOPA)-treated male rats. Castration produced a disruption of dishabituation responses to female urine, and this effect was reversed by treatment with L-DOPA. In the posterior olfactory bulb, 3,4-dihydroxyphenlacetic acid (DOPAC) levels were significantly increased in L-DOPA-treated animals compared with the vehicle-treated control and castrated groups. No significant differences in olfactory bulb norepinephrine or dopamine concentrations among the three treatment groups were obtained. The restoration of behavioral dishabituation responses following L-DOPA treatment suggests that the catecholaminergic system of the olfactory bulb may play a critical role in the recognition and possibly attractions for or preferences to female chemical cues.

Age related changes of social memory/recognition in male Fischer 344 rats

Two different habituation-dishabituation test paradigms were used to evaluate differences in social memory/recognition among 3-, 15- and 22-month-old male Fischer 344 rats. For test 1, males received three 2-min exposures to the same stimulus ovariectomized female, followed by three 2-min exposures to a different stimulus female with an inter-trial interval of 6 min. All groups showed a habituation response with investigation times decreasing on trials 2 and 3. Introduction of a different stimulus female on trial 4 (dishabituation) resulted in significant differences with investigation times of the 3-month animals being significantly greater than both the 15- and 22-month animals and those of the 15- being greater than the 22-month animals. Notably, the 22-month-old animals failed to dishabituate on this task. For test 2, all animals received two trials with different stimulus females used in each trial. While investigation times of the 3-month animals remained elevated in trial 2, indicative of an absence of habituation to these different stimuli, those of the 15- and 22-month-old animals decreased significantly, suggesting that habituation had occurred to the task and these animals failed to recognize differences in the stimuli. Taken together, these results demonstrate that the 22-month-old rats show enhanced habituation, but markedly deficient dishabituation responses compared to the 3-month-old animals, while the performance of the 15-month animals was intermediate. These results suggest an age dependent decrement in social memory/recognition processes in the male Fischer 344 rat.

Loss of gap junctions from DDT-treated rat liver epithelial cells

The mechanism by which the liver tumor promoter 1,1-bis(p-chlorophenyl)-2,2,2-trichloroethane (DDT) inhibits gap junctional intercellular communication (GJIC) in WB-F344 rat liver epithelial cells could involve gap junction loss and/or decreased gap junction channel permeability. We examined these two possibilities in the present study. Immunohistochemical studies using antibodies specific to connexin43, the major gap junction protein expressed by these cells, revealed that gap junction number and size were reduced during exposure to DDT. The reductions in gap junctions (33-91%) correlated with dose-dependent (1-10 microM) and time-dependent (0.5-4 h) decreases in cell-to-cell fluorescent dye-coupling (64-85%), as well as cellular levels of phosphorylated connexin43. These effects were reversible following removal of the tumor promoter from the culture medium, although cycloheximide reduced the level of gap junction reformation. The losses in gap junctions were not due to decreased connexin43 gene expression since steady-state levels of connexin43 mRNA were not similarly affected by DDT. Fenarimol (10 microM), a structural analog of DDT, did not inhibit GJIC and had no effect on gap junction structure or connexin43 expression. These data suggest that the inhibition of GJIC by DDT resulted from the removal of gap junctions from the plasma membrane and their degradation rather than simply a decrease in their permeability.

Phorbol 12-myristate 13-acetate stimulates proliferation and ductal morphogenesis and inhibits functional differentiation of normal rat mammary epithelial cells in primary culture

The effect of the tumor promoter phorbol 12-myristate 13-acetate (PMA) on proliferation and differentiation of normal mammary epithelial cells from 50-day-old virgin rats was investigated using a model system that allows for full morphological and functional development of the cells. In this model, mammary epithelial cells are grown within a reconstituted basement membrane in a defined serum-free medium. PMA at a concentration of 10(-6) M effected translocation of protein kinase C from cytosol to membrane. At the same concentration, it stimulated cell proliferation both in the presence and absence of EGF, and this stimulation was observed even when PMA exposure was limited to 15 min at the time of each media change. In contrast to the effect on proliferation, PMA at concentrations of 10(-7) and 10(-6) M inhibited functional differentiation as assessed by casein accumulation. Phorbol 12,13-dibutyrate at 10(-6) M also stimulated proliferation and inhibited casein accumulation and was more effective than PMA in both cases. In contrast, the nonactive tumor promoter 4-alpha PMA had no effect on either proliferation or differentiation. One of the most striking effects of PMA was its ability to stimulate an atypical ductal morphogenesis, as manifested by the formation of intricate web-like colonies, and to inhibit the development of the well-differentiated alveolar-like multilobular colonies. PMA was also shown to completely suppress the growth of the squamous-like colonies that develop when EGF is absent or deficient. These effects of phorbol esters in mammary epithelial cells to stimulate proliferation, inhibit functional differentiation, and stimulate the development of ductal colonies are consistent with the suggestion that the signal transduction pathways evoked by PMA could act to stimulate the growth of initiated cells or render normal cells more sensitive to carcinogen.

Depletion of olfactory bulb norepinephrine by 6-OHDA disrupts chemical cue but not social recognition responses in male rats

In the present experiment, 6-OHDA was infused directly into the olfactory bulb (OB) to produce a localized neurotoxic lesion. Habituation/dishabituation behavioral tests were then conducted to measure recognition responses to chemical cues (urine as a stimulus) and to social stimuli (ovariectomized rat as a stimulus). Infusion of 6-OHDA resulted in a near complete depletion of OB-norepinephrine (NE), whereas it had little effect (15% reduction) on OB dopamine (DA) contents. Nor were any significant effects on hypothalamic, hippocampal, olfactory tubercle, and corpus striatal NE and DA contents observed. Behaviorally, dishabituation responses to chemical cues were greatly impaired, however, there was relatively little effect on social behavior dishabituation responses. These results demonstrate that 6-OHDA can be used to produce a near complete but localized depletion of OB-NE. This treatment impairs dishabituation responses to chemical cues but not social stimuli indicating that OB-NE appears necessary for processing of chemical cue, but not social memory recognition process.

Role of olfactory bulb norepinephrine in the identification and recognition of chemical cues

In this report the role of olfactory bulb (OB) norepinephrine (NE) in the identification and recognition of urinary chemical cues was examined. In Experiment 1, sexually naive adult male Sprague-Dawley rats were treated with either the noradrenergic neurotoxin, DSP-4, or the water vehicle, and tested for their ability to identify and recognize urinary chemical cues using a habituation-dishabituation paradigm. Treatment with DSP-4 produced an overall decrease in the amount of investigation directed to urine stimuli, with greatest reductions to urine from Zucker females. Overall, DSP-4 treatment did not alter habituation-dishabituation responses. Animals treated with DSP-4 showed a significant reduction in OB-NE, but not dopamine, concentrations. In Experiment 2, hypothalamic catecholamine concentrations and serum samples assayed for testosterone were determined from identically treated animals. Although the NE and dopamine content in MBH was significantly lower in the DSP-4 group, no significant differences in testosterone concentrations were obtained between DSP-4 and controls. These results demonstrate that DSP-4 produces significant reductions in OB-NE and in the amount of investigation directed to urinary chemical cues from females without altering serum testosterone levels. Treatment with DSP-4 treatment does not impair the male rats' ability to demonstrate a habituation-dishabituation response.

Puberty acceleration in female mice induced with a partially purified male urine extract: effects on catecholamine release from the olfactory bulbs and hypothalamus

In the present experiment peri-pubertal female mice were treated with a partially purified puberty accelerating urine extract (PAUE). Mice treated with the PAUE showed an advance in the onset of puberty as indicated by significantly increased uterine weights. Treatment with the PAUE did not alter basal or potassium- (K+, 30 mM) stimulated release of catecholamines (dopamine or norepinephrine) from either anterior or posterior superfused olfactory bulb tissue fragments. There was, however, an overall significantly greater amount of basal and K(+)-stimulated release of NE from the posterior vs. the anterior olfactory bulb. Potassium-stimulated-, but not basal, release of catecholamines from the medial basal hypothalamus of PAUE-treated female mice were increased, with dopamine showing a statistically significant difference compared to water-treated females. These data demonstrate that treatment with the PAUE is a very effective means to accelerate the onset of puberty and results in accompanying increases in catecholaminergic activity, in particular dopamine, within the medial basal hypothalamus.

An artificial intelligence approach to DNA sequence feature recognition

The ultimate goal of the Human Genome project is to extract the biologically relevant information recorded in the estimated 100,000 genes encoded by the 3 x 10(9) bases of the human genome. This necessitates development of reliable computer-based methods capable of analysing and correctly identifying genes in the vast amounts of DNA-sequence data generated. Such tools may save time and labour by simplifying, for example, screening of cDNA libraries. They may also facilitate the localization of human disease genes by identifying candidate genes in promising regions of anonymous DNA sequence.

The rise of technology in Chinese hospitals

Chinese hospitals in the 1980s are in the midst of a technological revolution. Based upon data from several regions in China, this paper describes the political, organizational, economic, and philosophical changes which have accompanied the shift in focus from primary care medicine to high technology tertiary care. The increased authority of physicians, greater contact with the West, and increased funding for medical equipment are key factors in these changes. Although the Chinese state continues to control the administration and financing of most hospitals, the decentralizing reforms of Deng Xiaoping have undermined its ability to effectively plan for, and assess new technology. At present, limited resources prevent most regions from excessive technology acquisition, but the state must rebuild its planning capacity in order to foster rational allocation of scarce medical resources.