Localization of secretory phospholipase A2 in mouse cochlear tissues and cultured cells

OBJECTIVE

To localize the expression of secretory phospholipase A2 (sPLA2) in the cochlear duct.

DESIGN

By means of an immunocytochemistry technique that used rabbit anti-porcine pancreatic phospholipase A2 antiserum, sPLA2 sites were identified in vivo and in vitro in the adult mouse cochlear duct.

SUBJECTS

Eight C57BL/6N normal adult male mice (11-12 weeks old) (6 mice for the in vivo study, 2 mice for the in vitro study).

RESULTS

Different patterns of immunostaining for sPLA2 were observed in tissues of the cochlear duct. High levels of sPLA2 were detected in the following areas: the basal cells of the stria vascularis, the organ of Corti, the spiral ganglion, and the cochlear nerve; moderate levels of sPLA2 were found in the suprastrial and poststrial portions of the spiral ligament; low levels of sPLA2 were observed in the marginal and intermediate cells of the stria vascularis and the infrastrial portion of the spiral ligament. Immunoreactivity for sPLA2 also was detected in cultured marginal cells of the stria vascularis and in fibrocytes of the spiral ligament.

CONCLUSIONS

Secretory phospholipase A2 is present in mouse cochlear tissues and individual cultured cells. These results suggest that the levels of sPLA2 expression in the cochlear duct are cell specific.

Structural maturation of the interface region between the stria vascularis and spiral ligament in the neonatal rat cochlea

The ultrastructural morphology of the interface region between the stria vascularis (SV) and spiral ligament (SL) was examined in the neonatal rat cochlea via transmission electron microscopy. At postnatal day (PND) 3, morphology of both basal cells and fibrocytes was simple and immature. Only a small number of fibrocytes was observed in the SL. Intercellular junctions between basal cells and fibrocytes, and between adjacent fibrocytes, were few. At PND 7, the number of fibrocytes increased, and more organelles appeared within their cytoplasm. From PND 11 to 14, nuclei of the basal cells appeared to be more spindle-shaped and contained more heterochromatin. The cytoplasm of the fibrocytes was pale, and a greater number of cytoplasmic vesicles and mitochondria emerged. More intercellular junctions were observed between basal cells and fibrocytes at the interface region and between fibrocytes in the SL. By PND 21, the morphology of basal cells and fibrocytes and their intercellular junctions appeared to be adult-like. These morphological observations correlate with previous reports on the functional maturation of the developing rat cochlea.

[Health assessment on safe treatment of night-soil on schistosomiasis endemic areas]

The family size biogas tanks were built in the study site. Their effects were monitored. Faecal coliform and parasite eggs were examined before and after biogas digestion. The results of whole-year operation indicate that faecal coliform and parasite eggs can be reduced by 99.7% and 99.8%, respectively. The schistosome eggs survival experiment showed that the eggs all died off in 100 days of retention in biogas tanks. Therefore, the appropriate technology of nightsoil treatment can effectively interrupt the life cycle of schistosome.

Na,K-ATPase alpha- and beta-isoforms in the developing cochlea of the mouse

Immunohistochemistry was used to investigate the presence of Na,K-ATPase alpha- and beta-subunits isoforms (alpha 1, alpha 2, alpha 3, beta 1 and beta 2) in the cochlea of the mouse at different ages between embryological day (E) 19 and postnatal day (P) + 30. alpha 1 was mainly found in the stria vascularis and in the spiral ligament; it increased steadily from p+4. These data correlates well with the morphological and electrophysiological maturation of the cochlea. alpha 3 predominated in the spiral ganglia and the cochlear nerve. This finding is well in accordance with reports that alpha 3 seems to be associated with the nervous system. The beta-subunit was found mainly in those tissues where staining of the alpha-subunit also was seen. Both subunits were localized in tissue regions where fluid regulation is expected to play an important role. For some isoforms, the expression pattern of Na,K-ATPase during development in the mouse is different from that in the rat. The expression of Na,K-ATPase and that of glucocorticoid receptors during development in the inner ear of the mouse show a similar pattern, which may indicate that glucocorticoid receptors could be involved in regulating the expression of Na,K-ATPase.

Fluorescence in situ hybridization deletion mapping at 4p16.3 in bladder cancer cell lines refines the localisation of the critical interval to 30 kb

An allelotype analysis of transitional cell carcinoma of the bladder identified loss of heterozygosity (LOH) on chromosome arm 4p in 22% of tumours. In a more detailed LOH study of 178 bladder carcinomas, a 750 kb common region of deletion was identified between the markers D4S43 and D4S127 just telomeric to the Huntington disease locus. To refine this region of deletion at 4p16.3, we have carried out detailed fluorescence in situ hybridisation (FISH) analysis of 12 bladder cancer cell lines by using a chromosome 4 centromeric probe combined with a series of cosmid probes from contigs spanning the 750 kb region of deletion. A common 30 kb region of deletion was identified at 4p16.3 in over one-third of the bladder cancer cell lines analysed. The present study has refined the localisation of the critical region of deletion from 750 kb to approximately 30 kb, providing a precise starting point for positional cloning of the gene(s) involved in bladder cancer from within a very gene-rich region on chromosome band 4p16.3. This study demonstrates that FISH can be used for fine deletion mapping of potential tumour suppressor gene regions. The utilisation of FISH analysis to map chromosomal deletions should facilitate positional cloning of other genes as bacterial artificial chromosome (BAC) and yeast artificial chromosome (YAC) contigs of the human genome are established.

Appearance of glucocorticoid receptors in the inner ear of the mouse during development

CBA mice were sacrificed at different ages of developments at embryonic day 13 (E13), E14, E16, E19, E20 and postnatal day 1 (P1), P2, P3, P4, P6, P8, P10, P14, P16, P18, P20 and P30. The temporal bones were quickly removed and deep frozen in order to prepare cryosections for immunohistochemical staining with polyclonal antibodies against glucocorticoid receptors. The avidin-biotin, ABC-method was used to visualize binding. Both the vestibular and the cochlear regions of the inner ear were analysed. A faint staining of the crista ampullaris, the utricle and the cochlear duct was seen at E19; and staining became clearly visible at P1. A decrease in labelling was found at day 2-5 post partum whereafter an increased staining was again noticed until postnatal day 14 when an adult pattern was observed. The appearance of glucocorticoid receptors in the inner ear during development does not follow a linear curve. Further, the labelling pattern may indicate an impact of glucocorticoid receptors on the embryologic maturation itself as well as a functional role in the adult ear.

Responsiveness of alpha 1 and beta 1 cochlear Na, K-ATPase isoforms to thyroid hormone

The effects of thyroid hormone on Na, K-ATPase subunit isoforms under euthyroid (EUTH), hypothyroid (HYPO) and hyperthyroid (HYPER) states were investigated via immunocytochemistry and the use of polyclonal antibodies specific to each isoform (alpha 1, alpha 2, alpha 3 and beta 1, beta 2). In HYPO animals, there was a distinct decrease in Na, K-ATPase alpha 1 isoform immunoreactivity in the stria vascularis (SV), spiral ganglion (SG) cells, spiral limbus (SLi) and cochlear nerve (CN) as compared with that in EUTH animals by the 17th day of the experiment. Immunostaining of the alpha 1 isoform increased in HYPER animals as compared with that in HYPO animals, and reached a level comparable to that in EUTH animals after 2 days of triiodothyronine (T3) treatment. Levels of alpha 2, alpha 3 and beta 2 isoforms did not appear to be affected by T3 administration. By the 19th day of a low I2 diet, the immunoreactive intensity of the beta 1 isoform was reduced in cochlear tissues of HYPO animals as compared with that in EUTH animals. The immunoreactivity of the beta 1 isoform increased after treatment with T3 for 4 days and was comparable with levels in EUTH animals. These data indicate that alpha 1 and beta 1 isoforms within specific cochlear regions of the adult rat are responsive to thyroid hormone.

Cultivation of hepatitis C virus in primary hepatocyte culture from patients with chronic hepatitis C results in release of high titre infectious virus

To investigate the viral replication cycle and genomic heterogeneity of hepatitis C virus (HCV), we established an HCV cultivation system by using a primary hepatocyte culture from patients with chronic hepatitis C. Liver tissue was obtained by needle biopsy or surgery, then hepatocytes were isolated by collagenase digestion. After several weeks, we determined the HCV RNA titre of the cultured cells and supernatant by a competitive polymerase chain reaction (PCR) method. A significant amount of HCV RNA was observed in the cells and supernatant during cultivation. Negative-strand RNA, regarded as a marker of viral replication, could be detected by a strand-specific reverse transcription PCR method and the HCV core protein could be detected by immunofluorescence microscopy. Many HCV particles released into the supernatant were infectious. In addition, we compared the nucleotide sequences in the E2/NS1 region of pre- and post-cultivation hepatocytes for 8 weeks. At the beginning of the culture period, three major HCV types containing two subtypes were isolated. Following cultivation, the same types were isolated from the cultured hepatocytes in the same ratio as prior to cultivation. We could detect the same clones in this patient's serum, but in vivo we observed genetic variability over a 6 month interval. One clone detected throughout the 6 month period mutated extensively in the hypervariable region. These results indicated that HCV can replicate in cultured hepatocytes, and that infectious virions are released into the supernatant. This cultivation system should facilitate the study of HCV genomic heterogeneity, infection and replication.

Myometrial estradiol and progesterone receptor changes in preterm and term pregnancies

OBJECTIVE

To determine if labor is associated with changes in myometrial estradiol (E2) and progesterone receptors.

METHODS

Lower myometrial segments were obtained from women undergoing cesarean deliveries at term in labor (n = 10), term not in labor (n = 10), preterm in labor (n = 9), and preterm not in labor (n = 11). Western immunoblotting was used to determine the presence and molecular size of E2 and progesterone receptor proteins. Immunocytochemistry was used to determine E2 and progesterone receptor changes in preterm and term pregnancies.

RESULTS

Myometrium from pregnant women contained 74-kilodalton (kDa) E2 receptor and 94- and 110-kDa progesterone receptor proteins. These receptors are present in both myometrial smooth muscle and myometrial blood vessels. The nuclei of myometrial smooth muscle cells primarily contain both receptors. The immunostaining for progesterone receptors was less in patients in labor compared with those not in labor in preterm and term pregnancies. In comparing patients not in labor, the immunostaining for progesterone receptors was less at term compared with preterm pregnancy. Unlike the differences in progesterone receptors, there are no obvious differences in E2 receptor immunostaining in myometrial samples from all four groups of women.

CONCLUSION

A myometrial decrease in progesterone receptors, rather than an increase in E2 receptors, may play a role in the onset of labor in women with term or preterm pregnancies.

Generation of a high-resolution genetic map and a YAC contig of the Lurcher locus on mouse chromosome 6

Lurcher (Lc) is a semidominant mouse mutant that displays progressive neurodegeneration during perinatal development. This genetic lesion results in apoptotic neuronal death in a dosage dependent and cell autonomous manner in specific neurons during their terminal differentiation. To understand the molecular basis of the Lc mutation, we have adopted a positional cloning approach based on its location on mouse chromosome 6. To define the Lc locus, we have extended our previous analysis of an intersubspecific backcross between Mus m. castaneus and B6CBACa-Aw-j/A-Lc consisting of 504 animals (Norman et al. 1991). In addition, 580 animals of a generic backcross between Mus spretus and C57BL/6 (The European Collaborative Interspecific Backcross) were utilized for the fine genetic mapping of the Lc locus. Using three RFLP markers and nine microsatellite markers in the vicinity of the Lc locus, we determined the order and relative genetic distances of these markers at a resolution of 0.1 cM. The Lc mutation was mapped between two flanking markers, D6Mit121 and D6Mit175, separated by a genetic distance of 0.5 cM. We then initiated the cloning of the genomic region surrounding these two markers by screening a YAC library and characterizing YAC end sequences for further screening. This effort has resulted in the construction of a YAC contig consisting of 14 YACs and spanning a 3-Mb region. Markers isolated from these YACs were used to further define the Lc locus, resulting in a physical map that places the Lc gene within an estimated 300-kb interval. This set of YACs and markers will serve as DNA sources for the identification of the Lc gene.

Short circuiting stress protein expression via a tyrosine kinase inhibitor, herbimycin A

We set out to identify pharmacological means by which to activate the so-called heat shock or stress response and thereby harness the protective effect afforded to the cell by its acquisition of a thermotolerant phenotype. An earlier report by Murakami et al. (1991, Exp. Cell Res., 195: 338-344) described the increased expression of the 70 kDa heat shock proteins in human A431 cells exposed to Herbimycin A (HA), a benzoquinoid ansamycin antibiotic. We show here that treatment of cells with HA results in the increased expression of all of the constitutively expressed stress proteins and confers upon the cells a thermotolerant-like phenotype. Increases in the expression of the stress proteins continued for as long as the cells were exposed to the drug and was independent of the pre-existing levels of the stress proteins. Unlike heat shock or other metabolic stressors, we did not observe any adverse cellular effects following HA exposure. For example, unlike most agents/treatments that elicit the stress response HA-treated cells exhibited no obvious abnormalities with respect to protein maturation, protein insolubility, the integrity of the intermediate filament cytoskeleton, or overall cell viability. In addition, unlike other metabolic stressors, HA treatment did not result in the translocation of hsp 73 into the nucleus/nucleolus. Finally, for at least rodent cells, HA exposure did not result in any obvious activation of the heat shock transcription factor. Based on these findings, we suggest that HA treatment of cells results in a "short-circuiting" of the pathway(s) that normally regulates the expression of the stress proteins. These results are discussed as they pertain to the potential use of HA in animals as a way to harness the protective effects afforded by the stress response.

Decreased expression of functional human chorionic gonadotropin/luteinizing hormone receptor gene in human uterine leiomyomas

Human myometrium contains functional hCG/LH receptors. The purpose of this study was to determine whether or not leiomyomas that arise from myometrium also contain these receptors. Northern blotting demonstrated that leiomyomas and normal adjacent myometria contained hCG/LH receptor mRNA transcripts. Western immunoblotting showed that leiomyomas and corresponding normal myometria also contained 60- and 50-kDa receptor proteins. Ligand blotting revealed that only the 50-kDa receptor protein in leiomyomas and corresponding normal myometria could bind 125I-hCG and that this binding inhibited by excess unlabeled hCG. In situ hybridization and immunocytochemistry revealed that smooth muscle cells in leiomyomas and corresponding normal myometria contained the hCG/LH receptor mRNA transcripts and receptor proteins. The receptor levels were lower in leiomyomas than in corresponding normal myometria. However, the receptors were functional, as treatment with hCG resulted in a decrease of connexin-43 protein levels in leiomyomas as in normal myometria. In summary, human uterine leiomyomas express a functional hCG/LH receptor gene at a reduced level compared with that for normal corresponding myometria. This finding could be relevant to an understanding of the growth control mechanisms in leiomyomas and the manner in which medical therapy for leiomyomas might work.

[Proto-oncogene point mutation of c-Ha-ras in bronchogenic carcinoma]

11 bronchogenic carcinoma and 8 corresponding paracarcinoma specimens were detected for activating point mutation in codon 12 of c-Ha-ras gene by Southern blotting hybridization technique. The c-Ha-ras gene was found to be activated by point mutation in codon 12 in 8 of bronchogenic carcinoma and 1 of paracarcinoma tissues. The mutative and unmutative hybrid band was both discovered in 2 of paracarcinoma tissues. Analysis of clinical and pathological features, we conclude that: (1) The point mutation of c-Ha-ras gene codon 12 is found in 77.8% bronchogenic carcinoma among Chinese; (2) At least in part cases, mutation of c-Ha-ras gene codon 12 is not the "initiation" event, but may be a early-stage event in the pathogenesis; (3) No apparent association between the c-Ha-ras gene codon 12 mutation and pathological types, disease stages and history of smoking is present.

Multiple layers of regulation of human heat shock transcription factor 1

Upon heat stress, monomeric human heat shock transcription factor 1 (hHSF1) is converted to a trimer, acquires DNA-binding ability, is transported to the nucleus, and becomes transcriptionally competent. It was not known previously whether these regulatory changes are caused by a single activation event or whether they occur independently from one another, providing a multilayered control that may prevent inadvertant activation of hHSF1. Comparison of wild-type and mutant hHSF1 expressed in Xenopus oocytes and human HeLa cells suggested that retention of hHSF1 in the monomeric form depends on hydrophobic repeats (LZ1 to LZ3) and a carboxy-terminal sequence element in hHSF1 as well as on the presence of a titratable factor in the cell. Oligomerization of hHSF1 appears to induce DNA-binding activity as well as to uncover an amino-terminally located nuclear localization signal. A mechanism distinct from that controlling oligomerization regulates the transcriptional competence of hHSF1. Components of this mechanism were mapped to a region, including LZ2 and nearby sequences downstream from LZ2, that is clearly separated from the carboxy-terminally located transcription activation domain(s). We propose the existence of a fold-back structure that masks the transcription activation domain in the unstressed cell but is opened up by modification of hHSF1 and/or binding of a factor facilitating hHSF1 unfolding in the stressed cell. Activation of hHSF1 appears to involve at least two independently regulated structural transitions.

Expression of Na, K-ATPase alpha and beta isoforms in the neonatal rat cochlea

The postnatal expression of five Na, K-ATPase alpha (alpha 1, alpha 2, alpha 3) and beta (beta 1, beta 2) subunit isoforms in the rat cochlea was investigated by immunocytochemistry. High levels of expression of the alpha 1 and beta 2 isoforms were observed in stria vascularis (SV) at all developmental stages. alpha 1 and beta 1 isoforms showed a distinct time-dependent developmental expression pattern in tissues of the spiral ligament (SL) and spiral limbus (SLi). Limited, temporary expression of alpha 2 and alpha 3 subunit isoforms were found in SV and SL. Expression of each isoform was also seen in organ of Corti (OC), spiral ganglion (SG), cochlear nerve (CN) and Kölliker's Organ (KO). These observations suggest that individual isoforms may exert specific actions postnatally during final cochlear maturation.

Glucocorticoid receptor expression in the postnatal rat cochlea

The glucocorticoid receptor (GR) expression in the neonatal rat cochlea was investigated by utilization of a polyclonal antibody against GR, the immunoreactivity of which exhibited a distinct, age-dependent developmental pattern in tissues of the spiral ligament (SL). Immunostaining of GR appeared initially at the 7th postnatal day (PND), increased rapidly between the 14th and 21st PND, and reached adult-like expression levels by the 21st PND. Less pronounced, developmentally regulated expression patterns of GR were observed in cells of the spiral limbus (SLi), spiral ganglion (SG), organ of Corti (OC), and cochlear nerve (CN). For example, high expression levels of GR were observed in the SLi, SG and OC at 3 PND; subsequently, GR immunoreactivity levels decreased from 7 to 14 PND, and then GR immunoreactivity intensified in these regions by 21 PND. No remarkable changes in GR expression were observed in stria vascularis (SV). These data indicate that GR expression in the inner ear is tissue and age-specific, and that GR expression parallels both Na,K-ATPase expression and endocochlear potential development.

Cloning of rat grp75, an hsp70-family member, and its expression in normal and ischemic brain

Following metabolic stress a variety of gene products are induced in cells in the brain, some of which may protect the tissue from subsequent stresses. The heat shock proteins (hsps), in particular hsp70, have been widely studied in this context, but evidence for the involvement of known hsps in protection of the CNS is inconclusive. We have therefore undertaken the search for other stress-induced proteins which may mitigate ischemic injury. Beginning with degenerate RT-PCR, we have isolated a rat-brain cDNA encoding a protein highly similar to human grp75, a mitochondrial member of the hsp70-family of stress proteins. It is also highly similar to two non-mitochondrial proteins; mortalin, a senescence-related gene product, and pbp74, a protein implicated in B-cell peptide processing. Sequence structure and phylogenetic analyses predict mitochondrial localization and induction by a calcium ionophore and glucose deprivation in PC12 cells support its identification as rat grp75. In situ analysis of normal brain reveals an unusual distribution, with very high expression in neurons of the basal forebrain, reticular and subthalamic nuclei, globus pallidus, amygdala and elsewhere. grp75-mRNA is upregulated following focal brain ischemia in a distinctive fashion. When the degree of injury is small, induction occurs in the area of injury, similar to the pattern observed for hsp70. However, when the injury is extensive, hsr is upregulated in neurons outside the ischemic area. The induction of grp75 may represent a sensitive marker of metabolically compromised tissue.

Scrapie prions selectively modify the stress response in neuroblastoma cells

The fundamental event underlying scrapie infection seems to be a conformational change in the prion protein. To investigate proteins that might feature in the conversion of the cellular prion protein (PrPC) into the scrapie isoform (PrPSc), we examined mouse neuroblastoma N2a cells for the expression and cellular distribution of heat shock proteins (Hsps), some of which function as molecular chaperones. In scrapie-infected N2a (ScN2a) cells, Hsp72 and Hsp28 were not induced by heat shock, sodium arsenite, or an amino acid analog, in contrast to uninfected control N2a cells, while other inducible Hsps were increased by these treatments. Following heat shock of the N2a cells, constitutively expressed Hsp73 was translocated from the cytoplasm into the nucleus and nucleolus. In contrast, the distribution of Hsp73 in ScN2a cells was not altered by heat shock; the discrete cytoplasmic structures containing Hsp73 were largely resistant to detergent extraction. These alterations in the expression and subcellular translocation of specific Hsps in ScN2a cells may reflect the cellular response to the accumulation of PrPSc. Whether any of these Hsps feature in the conversion of PrPC into PrPSc or the pathogenesis of prion diseases remains to be established.

Helicobacter pylori infection and gastric metaplasia in the duodenum in China

Biopsy specimens from antral and duodenal mucosa were obtained from 64 patients with active duodenal ulcer and from 78 with nonulcer dyspepsia. Gastric metaplasia in the duodenal bulb was more frequent in patients with duodenal ulcer (82.5%) than in patients with dyspepsia and duodenitis (53.1%) or in patients with dyspepsia without duodenitis (34.5%). Helicobacter pylori infection in the duodenal bulb was found more often in patients with moderate to severe gastric metaplasia (62.3%) than in patients with mild gastric metaplasia (20%). Therefore, patients from a developing country, China, showed the same relationship between duodenitis, gastric metaplasia, duodenal colonization with H. pylori, and duodenal ulcer previously demonstrated in developed countries.

Inspection for gastric occult blood at regular intervals is the optimum program for the screening of esophageal-gastric cancer

Gastric occult blood screening has been performed for 242296 persons from 1986 to 1993. 30227 persons had positive reactions to the occult blood reagent. Among them, 17915 persons were asked to accept gastroscopy exam, and 638 esophageal-gastric cancers were found. The cancer detection rates were 3.56%. 4774 persons were asked to accept screening twice and 203 persons were asked to accept screening three times. After follow-up, the cancer detection rates were 2.11% for occult blood positive group if the screening was conducted once a year. The missing case was 0.77% for negative group and it was 0.05% in the same group if the screening was performed twice. Lastly, the missing case would be decreased to 0% when the patients undergone the exam, for three times in continuity. Two thirds of patients still belonged to the early-middle stage of cancer. The 5-year survival rates were 95.2%. The missing case of cancer would be reduced to 0% if the screening was conducted for three years in continuity. The death rates were deducted as well. It is certified that this method is the most effective and reliable way for reducing the death rate of cancer and screening of the upper digestive tract cancer.