cDNA library screening using the SOS recruitment system

The SOS recruitment system (SRS), a recently developed method for detecting protein-protein interactions, provides an attractive alternative to identify biologically important protein interactions. In SRS, the protein-protein interactions take place in the cytoplasm instead of the nucleus, as is the case in the conventional two-hybrid system. Although the SRS has overcome some of the disadvantages of the conventional two-hybrid system, it still has several problems and limitations. Here, we describe a new protocol for SRS library screening. A new combination of growth media to avoid the tedious step of replica plating greatly increases the number of independent colonies in a single library screening. Furthermore, we designed a pair of ras-specific primers and a one-step simple PCR to rule out the most abundant false positive, the mammalian ras cDNA, in SRS library screening.

Thermal-Dependent dehydration process and intramolecular cyclization of lisinopril dihydrate in the solid state

The pathway of dehydration and intramolecular cyclization of lisinopril dihydrate in the solid state was investigated using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and a combination of thermal analyzer with Fourier transform infrared microspectroscopy (thermal FT-IR microscopic system). The results indicate that the dehydration from the solid-state lisinopril dihydrate had a two-step process from dihydrate to monohydrate at 76 degrees C and then from monohydrate to anhydrate at 99-101 approximately C, which could be clearly observed from the above three methods. Only the thermal FT-IR microscopic system could give vital information on diketopiperazine (DKP) formation via intramolecular cyclization in anhydrous lisinopril. A new peak at 1670 cm(-1) assigned to the carbonyl band of DKP formation was clearly evidenced. The water of reaction byproduct was liberated at a temperature >157 degrees C and appeared on the IR spectra near 3200-3400 cm(-1). Moreover, the peak at 1574 cm(-1) assigned to carboxylate shifted to 1552 cm(-1) due to the DKP formation. The peak at 1670 cm(-1) related to the DKP formation changed slightly in intensity from 147 degrees C and significantly near 157 degrees C. DSC and TGA methods were poor for use in supplying information on DKP formation in lisinopril. The thermal FT-IR microscopic system is useful from the view point that it can quickly and directly show the solid-state stability of drug.

Age-associated changes of superoxide dismutase and catalase activities in the rat brain

Oxygen free radicals have been proposed to be involved in the process of aging. Superoxide dismutase (SOD) and catalase are important for antioxidative defense. In this study, profiles of SOD, catalase, and their mRNA levels were investigated in the frontal, parietal, temporal and occipital lobes, subcortex and cerebellum of male Wistar rats at ages 1-21 months. The total SOD and Mn SOD activities increased with age and exhibited higher levels at 6 and 12 months but decreased thereafter. Activity of catalase showed a similar trend and notably peaked at 12 months. The mRNA levels of Cu/Zn SOD, Mn SOD, and catalase remained constant in all areas tested (frontal, parietal, temporal and occipital lobes, and subcortex) except the cerebellum. Post-transcriptional regulation was involved in modulating the enzymes' activities during aging. Furthermore, the rate of mitochondrial generation of the superoxide anion (O(2)(-).) increased gradually with aging. Taken together, the results suggest that the increase of oxidative potential and the loss of proper antioxidant defense in the rats appear to be highly involved in the aging process of the brain.

[The study of mechanism by which mild hypothermia reduced delayed neuronal death after cerebral ischemia in gerbils]

AIM

To study the effect of mild hypothermia on delayed neuronal death as well as the relationship between hydroxyl radicals generation in hippocampus and the change of dopamine and ATP content in striatum following ischemia/reperfusion in gerbils.

METHODS

The ischemia was induced by occlusion the both carotid common arteries for 10 minutes in gerbils. Animals were divided into four groups: sham-operated group, ischemic group, ischemia/reperfusion group and mild hypothermic ischemia/reperfusin group. The numbers of delayed neuronal death were assessed by histological examination. OH. outputs in hippocampus and dopamine content in striatum were specifically identified and quantitated by high performance liquid chromatography (HPLC) coupled with electrochemical detection (ECD). ATP content in striatum was also determined by HPLC.

RESULTS

Mild hypothermia significantly reduced the numbers of damaged neurons in hippocampus CA1 subfield after ischemia in gerbils. In MH group, 2,3-DHBA outputs were much less than that in IR group (P < 0.01). Dopamine and ATP content in striatum were higher than those in IR group (P < 0.01).

CONCLUSION

Mild hypothermia could decrease the delayed neuronal death in gerbils by reducing hydroxyl radicals production in hippocampus and inhibiting dopamine release as well as prompting the recovery of ATP content in striatum following ischemia/reperfusion in gerbils.

[Expression of CD44s and CD44v6 in laryngeal squamous cell carcinoma and their significance]

OBJECTIVE

To study the correlation between the expression of CD44s, CD44v6 and the clinicopathological characters of laryngeal squamous cell carcinoma (LSCC) so as to analyze the role of them in occurrence and progression of LSCC.

METHOD

Expression of CD44 and CD44v6 in 46 cases of LSCC and 20 cases of adjacent normal tissues was inspected with immunohistochemical SP method.

RESULT

The expression of CD44s increased significantly in lymphnode metastasis group (94.4%) and stage III-IV group (96.2%), but decreased in non-lymphnode metastasis group (67.9%) and stage I-II group (55.0%). The expression of CD44v6 was lower (21.7%), which wasn't associated with any clinicopathological characters.

CONCLUSION

The role of CD44 and CD44v6 in carcinoma maybe dependent on the species, type of carcinoma, and the expression of CD44s may be a biologic marker to evaluate metastasis of LSCC.

Predictors of survival among elders suffering strokes in Taiwan: observation from a nationally representative sample

BACKGROUND AND PURPOSE

Cerebrovascular disease was the leading cause of death in Taiwan from 1963 to 1982. Deaths due to stroke now rank second only to cancer, with more deaths resulting from strokes than from any other single pathology. It is important to understand stroke prognosis among elderly stroke survivors, with respect to survival and attendant predictive factors, because aged population in Taiwan is growing rapidly. The aim of the present study was to discern factors affecting survival in stroke patients from a nationally representative elderly sample.

METHODS

A total of 99 stroke survivors, from a representative national sample of elders aged >/=65 years on December 31, 1988, whose strokes occurred in the period 1989-1993, were followed for mortality until July 1, 1995. Personal data were gathered through home interviews conducted by well-trained community nurses, and mortality data were obtained from the national census office by using identification card numbers. Cox proportional hazards regression analysis and the stepwise technique were used to search for important prognostic factors of survival.

RESULTS

Women experienced a higher mortality rate (139.8 per 1000 person-years) than men (126.4 per 1000 person-years), as age-adjusted for World Health Organization world-population figures. Stroke patients who received continuous treatment for diabetes experienced mortality risks similar to those of patients without diabetes and much lower risks than those with discontinuous diabetes treatment. Cognitive impairment was also an independent predictor of survival (relative risk 2.69, P<0.05). In addition, patients with both cognitive and mobility impairments had a 2- to 3-fold greater risk of mortality than those with only a single abnormality.

CONCLUSIONS

This first report on the various prognostic factors related to survival of elderly stroke patients in Taiwan's Chinese population emphasized the benefit of continuous diabetes treatment in improving survival chances. These stroke patients should also be monitored for cognitive and mobility impairments and undergo rehabilitation.

Selective malformation of the splenic white pulp border in L1-deficient mice

Lymphocytes enter the splenic white pulp by crossing the poorly characterized boundary of the marginal sinus. In this study, we describe the importance of L1, an adhesion molecule of the Ig superfamily, for marginal sinus integrity. We find that germline insertional mutation of L1 is associated with a selective malformation of the splenic marginal sinus. Other splenic structures remain intact. Immunofluorescence analysis of the extracellular framework of the spleen, using an Ab to laminin, reveals that L1 knockout mice have an irregularly shaped, discontinuous white pulp margin. Electron microscopic analysis shows that it is associated with bizarrely shaped marginal sinus lining cells at the periphery of the white pulp. These abnormalities correlate with the localization of L1 in normal mice in that L1 is normally expressed on marginal sinus lining cells at the white pulp border. These L1-immunopositive lining cells coexpress high levels of mucosal addressin cell adhesion molecule-1 and vimentin, indicating that they are of fibroblastic lineage and express a well-characterized addressin. Our findings are the first to implicate L1 in splenic lymphoid architectural development. Moreover, these findings help define the poorly characterized sinusoidal boundary across which mononuclear cells cross to enter the splenic white pulp.

The Drosophila caspase DRONC cleaves following glutamate or aspartate and is regulated by DIAP1, HID, and GRIM

The caspase family of cysteine proteases plays important roles in bringing about apoptotic cell death. All caspases studied to date cleave substrates COOH-terminal to an aspartate. Here we show that the Drosophila caspase DRONC cleaves COOH-terminal to glutamate as well as aspartate. DRONC autoprocesses itself following a glutamate residue, but processes a second caspase, drICE, following an aspartate. DRONC prefers tetrapeptide substrates in which aliphatic amino acids are present at the P2 position, and the P1 residue can be either aspartate or glutamate. Expression of a dominant negative form of DRONC blocks cell death induced by the Drosophila cell death activators reaper, hid, and grim, and DRONC overexpression in flies promotes cell death. Furthermore, the Drosophila cell death inhibitor DIAP1 inhibits DRONC activity in yeast, and DIAP1's ability to inhibit DRONC-dependent yeast cell death is suppressed by HID and GRIM. These observations suggest that DRONC acts to promote cell death. However, DRONC activity is not suppressed by the caspase inhibitor and cell death suppressor baculovirus p35. We discuss possible models for DRONC function as a cell death inhibitor.

Bile acid induction of cytokine expression by macrophages correlates with repression of hepatic cholesterol 7alpha-hydroxylase

In the studies reported herein, we show that two complementary experimental models: inbred strains of mice (i.e. C57BL/6 and C3H/HeJ), and a differentiated line of rat hepatoma cells (i.e. L35 cells), require the activation of cytokines by monocyte/macrophages to display bile acid negative feedback repression of cholesterol 7alpha-hydroxylase (CYP7A1). Feeding a bile acid-containing atherogenic diet for 3 weeks to C57BL/6 mice led to a 70% reduction in the expression of hepatic CYP7A1 mRNA, whereas no reduction was observed in C3H/HeJ mice. The strain-specific response to repression of CYP7A1 paralleled the activation of hepatic cytokine expression. Studies using cultured THP-1 monocyte/macrophages showed that the hydrophobic bile acid chenodeoxycholate, a well established potent repressor of CYP7A1, induced the expression of mRNAs encoding interleukin 1 (IL-1) and tumor necrosis factor alpha (TNFalpha). In contrast, the hydrophilic bile acid ursodeoxycholate, which does not repress CYP7A1, did not induce cytokine mRNA expression by THP-1 cells. Chenodeoxycholate activation of cytokines by THP-1 cells was blocked by the peroxisome proliferator-activated receptor gamma agonist rosiglitazone. The expression of cytokines (e.g. IL-1 and TNFalpha) by THP-1 cells paralleled with the ability of these cells to produce conditioned medium that when added to rat L35 hepatoma cells, repressed CYP7A1. Moreover, rosiglitazone, which blocks cytokine activation by macrophages, also blocked the repression of CYP7A1 normally exhibited by C57BL/6 mice fed the bile acid-containing atherogenic diet. The combined data indicate that the activation of cytokines may mediate CYP7A1 repression caused by feeding mice an atherogenic diet containing bile acids.

One or more labile proteins regulate the stability of chimeric mRNAs containing the 3'-untranslated region of cholesterol-7alpha -hydroxylase mRNA

Multiple AUUUA elements similar to those that regulate the degradation of several different mRNAs are conserved in the 3'-untranslated region (3'-UTR) of cholesterol-7alpha-hydroxylase (CYP7A1) mRNAs from several species. We examined if stabilization of mRNA decay could account for the >20-fold increase in the expression of CYP7A1 mRNA without a detectable change in transcription following dexamethasone treatment of rat hepatoma cells (L35 cells). Following RNA polymerase II-dependent transcription block or protein synthesis block, the decay of CYP7A1 mRNA displayed a short half-life ( approximately 30 min). Control experiments showed that in cells pre-treated with a RNA polymerase II inhibitor, dexamethasone had no detectable effect on CYP7A1 mRNA decay. Stable expression of luciferase reporter mRNAs in L35 cells showed that the CYP7A1 3'-UTR was required to observe a dexamethasone induction. To examine the hypothesis that a labile protein is required for dexamethasone-induced mRNA stabilization, cells were stably transfected with a tetracycline-repressible promoter that drives the expression of a green fluorescent protein analogue (ECFP) with or without the 3'-UTR of CYP7A1. Cells expressing ECFP with the 3'-UTR of CYP7A1 displayed a 3-fold dexamethasone induction of ECFP mRNA, whereas cells expressing ECFP without the 3'-UTR did not. Moreover, specific block of the transcription of ECFP containing the 3'-UTR by adding the tetracycline analogue doxycycline clearly displayed dexamethasone-induced stabilization of mRNA decay. These data provide compelling evidence that a putative labile protein and the 3'-UTR of CYP7A1 act together to decrease the rate of CYP7A1 mRNA degradation.

Crystal and molecular structure of an eight-coodinate N-methyltetraphenylporphyrin complex: diacetato(N-methyl-meso-tetraphenylporphyrinato)thallium(III)

The crystal structure of diacetato(N-methyl-meso-tetraphenylporphyrinato)thallium(III), Tl(N-Me-tpp)(OAc)2 (1), was established, and the coordination sphere around the Tl3+ ion is described as an eight-coordinate square-based antiprism in which two cis chelating bidentate OAc- groups occupy two apical sites. The plane of the three pyrrole nitrogen atoms (i.e., N(1), N(3), N(4)) strongly bonded to Tl3+ is adopted as a reference plane 3N. The pyrrole N(2) ring bearing the methyl group (i.e., C(45)H3) is the most deviated one from the 3N plane, making a dihedral angle of 21.4 degrees, whereas smaller angles of 9.1 degrees, 7.1 degrees, and 0.9 degree occur with pyrroles N(1), N(3), and N(4), respectively. Because of its larger size, the thallium(III) ion Tl3+ is considerably out of the 3N plane; its displacement of 1.17 A is in the same direction as that of the two apical OAc- ligands. The intermolecular acetate exchange process for 1 in THF-d8 solvent is examined through 1H NMR temperature-dependent measurements. In the slow-exchange region, the methyl and carbonyl carbons of the OAc- groups in 1 are separately located at delta 18.6 [3J(Tl-13C) = 405 Hz] and 170.8 [2J(Tl-13C) = 334 Hz] at -80 degrees C, respectively.

Novel gallium phosphate framework encapsulating trinuclear Mn3(H2O)6O8 cluster: hydrothermal synthesis and characterization of Mn3(H2O)6Ga4(PO4)6

A new manganese gallium phosphate, Mn3(H2O)6Ga4(PO4)6, has been synthesized under hydrothermal conditions at 150 degrees C and characterized by single-crystal X-ray diffraction, thermogravimetric analysis, magnetic susceptibility, and electron paramagnetic resonance (EPR) spectroscopy. It crystallized in the monoclinic space group, P2(1)/n, with a = 8.9468(4) A, b = 10.148(5) A, c = 13.5540(7) A, beta = 108.249(1) degrees, and Z = 2. The compound is unusual in that it is not only the first nonoranically templated MnGaPO phase but also the first instance where edge-shared trinuclear manganese-oxygen clusters are encapsulated in a metal phosphate lattice. The trimer involves a central Mn(H2O)4O2 octahedron, which links to two Mn (H2O)2O4 octahedra at trans edges. The Mn3(H2O)6O8 clusters reside in tunnels built from GaO5 trigonal bipyramids and PO4 tetrahedra. Our magnetic study revealed that superexchange interactions occurred between the neighboring MnII centers. A good fit of the magnetic susceptibility data for the isolated trimers was obtained by using a derived expression based on Van Vleck's equation. Unlike all existing linear trinuclear MnII complexes, the chi MT product in the range 8-4 K remains at a constant value corresponding to one spin S = 5/2 per three MnII centers. The Curie behavior at such low temperatures has been confirmed by EPR data. According to the thermogravimetric analysis/differential thermal analysis (TGA/DTA) results, the title compound is thermally stable up to ca. 200 degrees C.

Association of CYP1A1 and microsomal epoxide hydrolase polymorphisms with lung squamous cell carcinoma

Lung cancer is the leading cause of death among cancers in Taiwan. Although the etiology of lung cancer has yet to be defined, genetic variability in activities of metabolic enzymes has been correlated with lung cancer. In the present study, the possibility of association of CYP1A1 and microsomal epoxide hydrolase (HYL1) genetic polymorphisms with lung cancer was examined among 132 lung cancer patients and 259 controls in Taiwan. No significant association was observed for either CYP1A1 or HYL1 polymorphism alone and the overall incidence of lung cancer after adjusting for age, gender and smoking status. When cases were stratified according to histological type, there was significant association between CYP1A1*2A homozygote and squamous cell carcinoma (SCC) (odds ratio (OR) 2.86; 95% confidence interval (CI) 1.33-6.12). Similarly, the proportion of HYL1 genotypes corresponding to high or normal enzyme activities was higher in SCC than in controls (OR 1.96; 95% CI 1.04-3.70). A combination of susceptible CYP1A1 and HYL1 genotypes was found to be highly associated with lung cancer, especially with SCC (OR 6.76; 95% CI 2.29-19.10). Our results suggest that the combination of CYP1A1 and HYL1 polymorphisms is an important risk factor for lung SCC.

Heritable and inducible genetic interference by double-stranded RNA encoded by transgenes

Double-stranded RNA interference (RNAi) is an effective method for disrupting expression of specific genes in Caenorhabditis elegans and other organisms. Applications of this reverse-genetics tool, however, are somewhat restricted in nematodes because introduced dsRNA is not stably inherited. Another difficulty is that RNAi disruption of late-acting genes has been generally less consistent than that of embryonically expressed genes, perhaps because the concentration of dsRNA becomes lower as cellular division proceeds or as developmental time advances. In particular, some neuronally expressed genes appear refractory to dsRNA-mediated interference. We sought to extend the applicability of RNAi by in vivo expression of heritable inverted-repeat (IR) genes. We assayed the efficacy of in vivo-driven RNAi in three situations for which heritable, inducible RNAi would be advantageous: (i) production of large numbers of animals deficient for gene activities required for viability or reproduction; (ii) generation of large populations of phenocopy mutants for biochemical analysis; and (iii) effective gene inactivation in the nervous system. We report that heritable IR genes confer potent and specific gene inactivation for each of these applications. We suggest that a similar strategy might be used to test for dsRNA interference effects in higher organisms in which it is feasible to construct transgenic animals, but impossible to directly or transiently introduce high concentrations of dsRNA.

Proline inhibits aggregation during protein refolding

The in vitro refolding of hen egg-white lysozyme is studied in the presence of various osmolytes. Proline is found to prevent aggregation during protein refolding. However, other osmolytes used in this study fail to exhibit a similar property. Experimental evidence suggests that proline inhibits protein aggregation by binding to folding intermediate(s) and trapping the folding intermediate(s) into enzymatically inactive, "aggregation-insensitive" state(s). However, elimination of proline from the refolded protein mixture results in significant recovery of the bacteriolytic activity. At higher concentrations (>1.5 M), proline is shown to form loose, higher-order molecular aggregate(s). The supramolecular assembly of proline is found to possess an amphipathic character. Formation of higher-order aggregates is believed to be crucial for proline to function as a protein folding aid. In addition to its role in osmoregulation under water stress conditions, the results of this study hint at the possibility of proline behaving as a protein folding chaperone.

NAD(P)H: quinone oxidoreductase polymorphism and lung cancer in Taiwan

Lung cancer is one of the leading causes of death in Taiwan since 1996. Genetic variation in metabolic activation or detoxification enzymes has been associated with the occurrence of lung cancer. NAD(P)H:quinone oxidoreductase (NQO1) enzyme is a cytosolic two-electron reductase thought to be involved in bioactivation and detoxification of environmental carcinogens. The possible association between NQO1 genetic polymorphism and lung cancer risk was examined among 95 male smokers without cancer and 100 male smokers with lung cancer in Taiwan. There was no significant difference in the proportion of wild-type NQO1 among all cancer cases and controls. When cases were stratified according to histological subtypes, the wild-type NQO1 was more common in adenocarcinoma than in controls. The odds ratio was 2.93 (95% confidence interval, 1.23-7.02; p = .02). This is the first observation for the positive association of this locus with lung cancer in an Asian population. These results suggest that NQO1 polymorphism is an important genetic risk factor for lung adenocarcinoma among smokers in Taiwan.

Cytochrome P4502E1 genetic polymorphisms and lung cancer in a Taiwanese population

Cytochrome P4502E1 (CYP2E1) is involved in metabolic activation of carcinogenic nitrosamines, benzene and low molecular weight halogenated hydrocarbons. In this study, we assessed the association between CYP2E1 RsaI and DraI genetic polymorphisms and lung cancer in a Taiwanese population. The RsaI genotype distribution was significantly different between 119 lung cancer patients and 231 non-cancer controls. The homozygote variants of RsaI genotypes were more common in controls (6.9%) than in lung cancer patients (0.8%). The estimated odds ratio (OR) was 0.11 (95% confidence interval (CI), 0.01-0.87). After adjusting for age, sex, and smoking status, the OR was 0.12 (95%, CI, 0.02-0.95). This is the first observation of a positive association between this locus and lung cancer in an Asian population. No significant differences in CYP2E1 DraI genotype distributions were found between cases and controls. The results of this study indicate that CYP2E1 RsaI polymorphism, but not DraI polymorphism, may contribute to the development of lung cancer in Taiwan.

Height and weight percentile curves of Beijing children and adolescents 0-18 years, 1995

Nationwide growth survey has been performed once every 10 years in Mainland China since 1975. However, no percentile growth curves for children from birth to 18 years have ever been constructed for clinical use. The third survey was performed in 1995 and from this survey, data of the Beijing population were retrieved to construct the height for age and weight for age percentile curves. A total of 12218 healthy children were examined for height and weight, using the standardized methods. Height, but not weight, was normally distributed. Smoothing was performed separately for each sex, using JPA2 model for mean height for age > 2 years. Otherwise, smoothing was performed for the following curves by polynomial equations up to the order of the 5th degree for height and 12th degree for weight, mean height for age < 2 years, SD curve of height for age from birth to 18 years, median weight for age < 2 years, median weight for age > 2 years, differences between the 3rd, 10th, 25th, 75th, 90th, 97th centiles and the median for age from birth to 18 years. The predicted adult height was 173.43cm for boys and 160.86 cm for girls, with age of peak velocity at 13 years and 11.5 years for boys and girls respectively. Compared to those in Hong Kong, they were 2.3-2.5 cm taller signifying a geographical difference in growth even within one country. Compared to the Beijing data collected in 1975 and 1985 the secular changes in growth were more obvious in the first decade, suggesting that the Beijing population was approaching the optimal adult height.

The Drosophila caspase inhibitor DIAP1 is essential for cell survival and is negatively regulated by HID

Drosophila Reaper (RPR), Head Involution Defective (HID), and GRIM induce caspase-dependent cell death and physically interact with the cell death inhibitor DIAP1. Here we show that HID blocks DIAP1's ability to inhibit caspase activity and provide evidence suggesting that RPR and GRIM can act similarly. Based on these results, we propose that RPR, HID, and GRIM promote apoptosis by disrupting productive IAP-caspase interactions and that DIAP1 is required to block apoptosis-inducing caspase activity. Supporting this hypothesis, we show that elimination of DIAP1 function results in global early embryonic cell death and a large increase in DIAP1-inhibitable caspase activity and that DIAP1 is still required for cell survival when expression of rpr, hid, and grim is eliminated.

Retinoid and androgen regulation of cell growth, epidermal growth factor and retinoic acid receptors in normal and carcinoma rat prostate cells

Recent in vivo and in vitro studies suggest that retinoic acid receptor (RAR)-mediated processes may be involved in androgen regulation of prostate cells in a manner that may be altered during prostatic carcinogenesis. We tested this hypothesis in the newly established carcinoma and non-carcinoma rat prostate epithelial cell lines, NRP-154 and NRP-152, respectively. In DMEM/F-12 medium supplemented with 10% charcoal stripped fetal calf serum (cFCS), the number of both NRP-152 and NRP-154 cells were stimulated by testosterone (T), with a 4-fold greater effect in NRP-152 than in NRP-154 cells. Retinoic acid (RA) alone also stimulated the growth of NRP-152 cells, but failed to induce cell growth of NRP-154 cells. Importantly, the level of RAR alpha mRNA was elevated whereas the levels of RAR gamma and androgen receptor (AR) mRNA were lower in NRP-154 cells compared to those in NRP-152 cells. Treatment of NRP-152 cells with increasing doses of T resulted in a dose-dependent decrease and rebound of the level of RAR alpha and gamma mRNA in NRP-152 cells; these effects were not apparent, if not reversed, in NRP-154 cells. Both ligand binding and Western blot analyses revealed that epidermal growth factor receptor (EGF-R) was stimulated by 20 nM T but was suppressed by 0.1 microM RA, which also attenuated the stimulating effects of T on EGF-R in NRP-152 and to a lesser extent in NRP-154 cells. The differences in the level and androgen regulation of RAR mRNAs and reciprocal regulation of EGF-R expression by T and RA between NRP-154 and NRP-152 cells suggest that variations in the EGF-R and RAR signal events may contribute to differences in growth rate between these two cell lines.

A cloning method to identify caspases and their regulators in yeast: identification of Drosophila IAP1 as an inhibitor of the Drosophila caspase DCP-1

Site-specific proteases play critical roles in regulating many cellular processes. To identify novel site-specific proteases, their regulators, and substrates, we have designed a general reporter system in Saccharomyces cerevisiae in which a transcription factor is linked to the intracellular domain of a transmembrane protein by protease cleavage sites. Here, we explore the efficacy of this approach by using caspases, a family of aspartate-specific cysteine proteases, as a model. Introduction of an active caspase into cells that express a caspase-cleavable reporter results in the release of the transcription factor from the membrane and subsequent activation of a nuclear reporter. We show that known caspases activate the reporter, that an activator of caspase activity stimulates reporter activation in the presence of an otherwise inactive caspase, and that caspase inhibitors suppress caspase-dependent reporter activity. We also find that, although low or moderate levels of active caspase expression do not compromise yeast cell growth, higher level expression leads to lethality. We have exploited this observation to isolate clones from a Drosophila embryo cDNA library that block DCP-1 caspase-dependent yeast cell death. Among these clones, we identified the known cell death inhibitor DIAP1. We showed, by using bacterially synthesized proteins, that glutathione S-transferase-DIAP1 directly inhibits DCP-1 caspase activity but that it had minimal effect on the activity of a predomainless version of a second Drosophila caspase, drICE.

G169R mutation diminishes the metabolic activity of CYP2D6 in Chinese

The molecular basis of the reduced ability of a Chinese to metabolize debrisoquine was explored by sequencing all of the nine exons of the CYP2D6 gene. The subject has T188, A1846, T2938, and C4268 (CYP2D6*14) instead of C188, G1846, C2938, and G4268 as in wild-type subjects. XbaI restriction fragment length polymorphism indicated that the subject has a 29-kb allele and a gene deletion (11.5 kb) in another allele (CYP2D6*5). A CYP2D6*14 allele together with a CYP2D6*5 allele may cause the poor metabolism of the subject. T188, T2938, and C4268 are common haplotypes in Chinese-extensive metabolizers. The effect of G1846 to A mutation in CYP2D6 metabolism has not been reported. A polymerase chain reaction-based endonuclease digestion test was designed for the G/N1846 polymorphism and 124 Chinese subjects were screened. With DNA sequencing, two other subjects showed the heterozygous G/A1846 and have a relatively high metabolic ratio of debrisoquine hydroxylation. The site-directed mutagenesis was used to create recombinant CYP2D6 cDNA with T188, A1846, or C4268. The cDNA was then transfected into Rat-1 cells. The transfection was confirmed by Southern, Northern, and Western blots. Based on the same microsomal protein level, the bufuralol 1'-hydroxylation activity of CYP2D6(T188) or CYP2D6(A1846) was significantly lower than that of the wild-type CYP2D6. P34S mutation (C188 to T) significantly decreased CYP2D6 activity. G169R mutation (G1846 to A) also decreased CYP2D6 activity and may further reduce the metabolic activity of CYP2D6 protein with P34S, R296C, and S486T mutations.

Translocation-arrested apolipoprotein B evades proteasome degradation via a sterol-sensitive block in ubiquitin conjugation

In this study, we explored how sterol metabolism altered by the expression of cholesterol-7alpha-hydroxylase NADPH:oxygen oxidoreductase (7alpha-hydroxylase) affects the ubiquitin-dependent proteasome degradation of translocation-arrested apoB53 in Chinese hamster ovary cells. Stable expression of two different plasmids that encode either rat or human 7alpha-hydroxylase inhibited the ubiquitin conjugation of apoB and its subsequent degradation by the proteasome. Oxysterols (25-hydroxycholesterol and 7-ketocholesterol) reversed the inhibition of apoB degradation caused by 7alpha-hydroxylase. The combined results suggest that the normally rapid proteasome degradation of translocation-arrested apoB can be regulated by a sterol-sensitive polyubiquitin conjugation step in the endoplasmic reticulum. Blocked ubiquitin-dependent proteasome degradation caused translocation-arrested apoB to become sequestered in segregated membrane domains. Our results described for the first time a novel mechanism through which the "quality control" proteasome endoplasmic reticulum degradative pathway of translocation-arrested apoB is linked to sterol metabolism. Sterol-sensitive blocked ubiquitin conjugation appears to selectively inhibit the proteasome degradation of apoB, but not 7alpha-hydroxylase protein, with no impairment of cell vitality or function. Our findings may help to explain why the hepatic production of lipoproteins is increased when familial hypertriglyceridemic patients are treated with drugs that activate 7alpha-hydroxylase (e.g. bile acid-binding resins).

Oncogenic ras induces gastrin gene expression in colon cancer

BACKGROUND & AIMS

The expression of gastrin, as a tumor growth factor, is significantly increased in some colon cancers compared with the low levels found in normal mucosa. The aim of this study was to elucidate the transcriptional mechanisms of gastrin induction in colon cancer.

METHODS

Gastrin messenger (mRNA) levels and K-ras genotype were determined in colon cancer cell lines and surgical specimens. Colon cancer cells were transfected with oncogenic ras expression vectors, and transcriptional activity was assayed with gastrin-luciferase reporter genes.

RESULTS

Colon cancer cell lines and tissues with K-ras mutations all had significantly higher gastrin mRNA levels than those that were ras wild type. Treatment of several ras mutant cell lines with PD98059, an inhibitor of mitogen-activated protein kinase kinase, resulted in a decrease in endogenous gastrin mRNA levels. The effects of ras on gastrin expression appeared to be mediated through the gastrin promoter because transfection of oncogenic ras and activated raf expression vectors both induced gastrin-promoter, luciferase-reporter genes. The inductive effects of oncogenic ras could be blocked by the coexpression of dominant negative forms of raf and extracellular regulated kinase.

CONCLUSIONS

Oncogenic ras induces gastrin gene expression through activation of the Raf-MEK-ERK signal transduction pathway.

Physical training modifies the age-related decrease of GAP-43 and synaptophysin in the hippocampal formation in C57BL/6J mouse

We investigated the effect of a moderate amount of prolonged physical training initiated at 3 months of age on the expression of GAP-43 and synaptophysin in the hippocampal formation. C57BL/6J mice were divided into three groups which were trained (24 months old), sedentary (24 months old) and young (3 months old). From 3 months of age on, mice of trained group were treated with voluntary running wheel for 1 h each day (5 days per week) until 24 months of age (21 months running), whereas mice of sedentary group were put in immobilized wheels for the same time. Using immunohistochemistry and image analysis system, GAP-43 and synaptophysin were analysed quantitatively in the CA1, CA3 areas and the dentate gyrus of the hippocampal formation. As compared with young mice, the densities of GAP-43 and synaptophysin immunostaining showed a significant decrease in the hippocampal formation in sedentary group (P<0.01). After 21 months of running, the densities of GAP-43 and synaptophysin immunostaining significantly increased in the examined areas of the hippocampal formation in trained mice compared to their age-matched sedentary controls (P<0.05, 0.01). These results indicate that a moderate amount of prolonged physical training could modify the age-related decrease of the expression of GAP-43 and synaptophysin in the hippocampal formation, and that the increased expression of GAP-43 and synaptophysin might be associated with the anatomical sprouting and synaptogenesis.

Effect of physical training on the age-related changes of acetylcholinesterase-positive fibers in the hippocampal formation and parietal cortex in the C57BL/6J mouse

We investigated the effect of a moderate amount of prolonged physical training initiated at 3 months of age on the age-related changes of the hippocampal and cortical cholinergic fibers. A total of 80 male C57BL/6J mice were divided into five groups which were trained (including adult and old trained, AT and OT), sedentary (adult and old sedentary, AS and OS) and young (Y). From 3 months old, the mice of the trained groups were treated with a voluntary running wheel for 1 h each day, 5 days per week. AT had been trained up to 13-month-old whereas OT up to 24 months old. At the same time, the mice of the sedentary groups were put in immobilized wheels. We set the criterion for effective training in the trained mice such that the heart-to-body weight ratio should be at least 2 S.D. above the mean in the age-matched groups. Using AChE histochemistry and stereology, the AChE-positive fibers were analyzed quantitatively in the molecular layers in CA1, CA3 and the dentate gyrus of the hippocampal formation, and in III, V layers in the motor and somatosensory cortex. Comparison of Y, AS and OS (3, 13 and 24 months of age) showed minimum AChE-positive fiber density in the hippocampal formation and the cortex in OS (P < 0.01). After 10 and 21 months of running, the AChE-positive fibers in all regions examined in the trained groups were significantly increased compared to their age-matched controls (P < 0.05 or 0.01). In the hippocampal formation, the increase was about 17% in AT and 23% in OT, whereas, in the cortex, it was 13% in AT and 22% in OT. These results indicated that a moderate amount of prolonged physical training could modify the age-related loss of cholinergic fibers in the hippocampal formation and cortex, furthermore the modified loss of cholinergic fibers might be associated with the regeneration of hippocampal and cortical cholinergic fibers stimulated by chronic running.

Sialographic characterization of the normal parotid gland of the miniature pig

OBJECTIVE

To characterize the structure of the parotid gland of the miniature pigs (minipig).

METHODS

Sialographic, anatomical, histological and ultrastructural studies of the parotid gland were performed on 11 minipigs.

RESULTS

Sialograms showed a long main duct and a triangular shaped gland. All branching ducts extended from the inferior-posterior margin of the main duct. No accessory glands were found. Typical serous acini were found microscopically and histochemically.

CONCLUSION

This study provides basic structural information on the parotid gland of the minipig.

Changes in populations of Listeria monocytogenes inoculated on packaged fresh-cut vegetables

A variety of wholesale and retail packaged vegetables and salads were inoculated with a mixture of strains of Listeria monocytogenes and incubated at 4 and 10 degrees C. Whole rutabagas, butternut squash, and onions, as well as packaged Caesar salad, carrots, coleslaw mix, and stir-fry vegetables were purchased from local supermarkets in the Ottawa area. L. monocytogenes population levels remained constant on all fresh-cut vegetables stored at 4 degrees C for 9 days, except for carrots and butternut squash: counts of cell numbers declined on carrots and increased on the butternut squash. Fresh-cut vegetables stored at 10 degrees C, however, supported good growth of L. monocytogenes on all vegetables tested, except for chopped carrots, where the population decreased approximately 2 log units over a 9-day storage period. As in the situation with the produce stored at 4 degrees C, butternut squash supported the highest rate of cell growth. In addition, Caesar salad and coleslaw mix were kept at 25 degrees C for 1 or 2 days before subsequent storage at 4 or 10 degrees C to stimulate extreme temperature-abuse conditions. In Caesar salad stored at 4 degrees C, by day 6 an initial 24- and 48-h temperature abuse at 25 degrees C led to a 1.21- and 2.55-log-unit population increase, respectively, over the control. Similar increases were observed on Caesar salads stored at 10 degrees C. Compared to Caesar salad, coleslaw mix temperature-abused at 25 degrees C and then stored at 4 degrees C supported slightly greater increases in the population of L. monocytogenes, i.e., a 3.22- and 3.83-log-unit increase over the control for the 1- and 2-day abused samples, respectively. Coleslaw mix samples temperature-abused and then stored at 10 degrees, however, only showed log unit increases of 1.75 and 1.94, respectively, compared to the controls. These results point to the importance of strict temperature control to prevent or reduce the growth of L. monocytogenes cells on fresh-cut vegetables.

Investigation of the clinical value of total saliva flow rates

The symptom of dry mouth was correlated with unstimulated (UWSFR) and stimulated (SWSFR) whole-saliva flow rate on chewing medical paraffin in 62 patients with dry-mouth complaints (30 with Sjögren's syndrome, 32 with sialosis) and 23 controls. The symptom of dry mouth was classified into grades 0,1,2,3,4 according to a Treatment Emergent Symptom Scale (TESS). UWSFR and SWSFR were determined after fasting in the morning. UWSFR was 0.070 +/- 0.089 ml/min in Sjögren's syndrome, 0.175 +/- 0.115 ml/min in sialosis, 0.330 +/- 0.188 ml/min in controls. SWSFR was 0.709 +/- 0.720 ml/min in Sjögren's syndrome, 1.561 +/- 0.867 ml/min in sialosis, 1.894 +/- 0.661 ml/min in controls. A highly significant correlation was found between TESS score and UWSFR and between TESS score and SWSFR. Only UWSFR was decreased in the patients with a TESS score of 1 or 2, while both UWSFR and SWSFR were significantly decreased in the patients with TESS scores of 3, 4. It is concluded that UWSFR is more sensitive in relation to dry-mouth complaints than SWSFR, and that a mild dry mouth is mainly related to decreased UWSFR.

Incidence of NIDDM and the effects of gender, obesity and hyperinsulinaemia in Taiwan

Our aim is to determine non-insulin-dependent diabetes mellitus (NIDDM) incidence in Taiwan and examine its relation to obesity and hyperinsulinaemia in Chinese men and women. A total of 995 men and 1195 women aged 35-74 years free from diabetes in two townships in Taiwan were followed up with a second examination. At baseline general and metabolic data were recorded, and detailed anthropometric parameters and plasma glucose and insulin were assessed. World Health Organisation (WHO) criteria of fasting glucose 7.8 mmol/l or greater was utilized for defining diabetes. The age-standardized incidence rate based on the United States population in 1970 was 9.3/1000 (CI 5.8-12.8) in men and 9.3/1000 (CI 6.2-12.4) in women and the based on the WHO population in 1976 was 8.9/1000 (CI .5-12.3) in men and 8.9/1000 (CI 5.9-11.9) in women for the Chinese who had a mean BMI slightly greater than 24 (kg/m2). The predictability of the plasma glucose level was greater than that of the insulin level and the obesity indices. NIDDM incidence increased approximately threefold with each 0.67 mmol/l increase in plasma glucose level in men and women. The present study demonstrated the essential relationship of not only BMI but also central obesity indices (such as subscapular and waist circumference) to the incidence of NIDDM among men and women and a stronger relationship between NIDDM incidence and obesity in women than in men. The predictive effects of obesity indices and fasting plasma insulin values on NIDDM risk were independent of each other in men. Obesity and hyperinsulinaemia each without the presence of the other can lead to an increased risk of NIDDM. In women the NIDDM incidence increased more than additively in those with both obesity and hyperinsulinaemia compared to those with single obesity or hyperinsulinaemia. A slightly higher incidence of NIDDM in Taiwan than in western countries was found. The importance of obesity is indicated for predicting NIDDM in the community. Hyperinsulinaemia was found to play a significant role in predicting NIDDM incidence independent of obesity in men and synergistically with obesity in women.

Expression of nm23-H1 in human meningioma cells

The expression of nm23-H1 has been demonstrated to be highly correlated with the metastatic potential of various tumors. In the present investigation, meningiomas of different pathological grades were used to study on their nm23-H1 expression. Immunohistochemistry showed that nm23-H1 was expressed mainly in the cytoplasm especially in the perinuclear region in explants under short-term culture. Western-blotting demonstrated the specific expression of nm23 protein in all tumor samples. The expression was also found to be sex-dependent on tumor progression in female, but not in male patients. RT-PCR results confirmed nm23-H1 expression was higher in benign tumors than in their normal counterpart. Our observations thus suggest that nm23-H1 may play an important role in the progression of meningiomas in female patients.

Coordinate regulation of lipogenesis, the assembly and secretion of apolipoprotein B-containing lipoproteins by sterol response element binding protein 1

Stable plasmid-driven expression of the liver-specific gene product cholesterol 7alpha-hydroxylase (7alpha-hydroxylase) was used to alter the cellular content of transcriptionally active sterol response element binding protein 1 (SREBP1). As a result of stable expression of 7alpha-hydroxylase, individual single cell clones expressed varying amounts of mature SREBP1 protein. These single cell clones provided an opportunity to identify SREBP1-regulated genes that may influence the assembly and secretion of apoB-containing lipoproteins. Our results show that in McArdle rat hepatoma cells, which normally do not express 7alpha-hydroxylase, plasmid-driven expression of 7alpha-hydroxylase results in the following: 1) a linear relationship between (i) the cellular content of mature SREBP1 and 7alpha-hydroxylase protein, (ii) the relative expression of 7alpha-hydroxylase mRNA and the mRNA's encoding the enzymes regulating fatty acid, i.e. acetyl-CoA carboxylase and sterol synthesis, i.e. HMG-CoA reductase, (iii) the relative expression of 7alpha-hydroxylase mRNA and microsomal triglyceride transfer protein mRNA, a gene product that is essential for the assembly and secretion of apoB-containing lipoproteins; 2) increased synthesis of all lipoprotein lipids (cholesterol, cholesterol esters, triglycerides, and phospholipids); and 3) increased secretion of apoB100 without any change in apoB mRNA. Cells expressing 7alpha-hydroxylase contained significantly less cholesterol (both free and esterified). The increased cellular content of mature SREBP1 and increased secretion of apoB100 were concomitantly reversed by 25-hydroxycholesterol, suggesting that the content of mature SREBP1, known to be decreased by 25-hydroxycholesterol, mediates the changes in the lipoprotein assembly and secretion pathway that are caused by 7alpha-hydroxylase. These data suggest that several steps in the assembly and secretion of apoB-containing lipoproteins by McArdle hepatoma cells may be coordinately linked through the cellular content of mature SREBP1.

Cholesterol 7alpha-hydroxylase influences the expression of hepatic apoA-I in two inbred mouse strains displaying different susceptibilities to atherosclerosis and in hepatoma cells

C57BL/6 mice are susceptible to diet-induced atherosclerosis, whereas BALB/c mice are resistant. The susceptibility of C57BL/6 mice has been linked to decreased plasma HDL cholesterol in response to a diet containing fat, cholesterol, and cholic acid. Feeding C57BL/6 mice a diet consisting of fat and cholesterol, but no cholic acid, increased plasma high density lipoprotein (HDL) cholesterol. The increase in HDL was associated with increases in both plasma apolipoprotein (apo)A-I and hepatic apoA-I mRNA. Supplementation of the cholesterol-rich diet with cholic acid inhibited the stimulatory effect of cholesterol on hepatic apoA-I mRNA expression, resulting in similar hepatic apoA-I mRNA levels compared to chow-fed mice. Atherosclerosis-resistant BALB/c mice were also resistant to diet-induced changes in plasma HDL, apoA-I, and hepatic apoA-I mRNA levels. Previous studies showed that the diets changed both the activity and mRNA encoding the liver specific enzyme 7alpha-hydroxylase (1993.J. Lipid Res. 34: 923-931). In both strains of mice, hepatic expression of apoA-I and 7alpha-hydroxylase mRNA varied in parallel. Whereas susceptible C57BL/6 mice also showed a significant correlation between HDL cholesterol and expression of 7alpha-hydroxylase, no such correlation was observed in BALB/c mice, suggesting that genetic differences in HDL metabolism, not hepatic apoA-I synthesis, are responsible for the strain specific differences in plasma HDL levels. The finding that lecithin: cholesterol acyltransferase (LCAT) activity was significantly decreased in C57BL/6 mice, but not in BALB/ c mice fed the atherogenic diet, further supports this conclusion. Additional studies show that McArdle hepatoma cells stably expressing plasmid-derived rat 7alpha-hydroxylase recapitulated the parallel linear relationship between 7alpha-hydroxylase and apoA-I mRNA expression observed in both strains of mice. These data link hepatic apoA-I mRNA expression to hepatic cholesterol/bile acid metabolism.

Production of chitinase from shellfish waste by Pseudomonas aeruginosa K-187

The production of chitinolytic enzyme by Pseudomonas aeruginosa K-187, using shrimp and crab shell powder (SCSP) as the carbon source, was studied. It was observed that chemically treated SCSP induced a significant increase of enzyme production, as compared with untreated SCSP. Spent HCl and NaOH from the chitin production industry was used to process SCSP. Various strategies of SCSP processing are examined and compared in terms of chitinolytic enzyme production. A three-and-one-half-fold increase of enzyme production (0.68 U/ml to 2.4 U/ml) was attained using HCl/NaOH treated SCSP. The microorganism (K-187) was isolated from soil in Taiwan and has been characterized and reported in a previous paper.

The large ribosomal protein gene cluster of a cryptomonad plastid: gene organization, sequence and evolutionary implications

The complete sequence of the major ribosomal protein gene cluster of the plastid genome of the cryptomonad alga Guillardia theta (formerly Cryptomonas phi) is presented. The ribosomal protein genes (corresponding to the S10, spc, alpha and L13/S9 operons of E. coli) are found upstream of the previously reported plastid str operon, and transcribed in the same orientation. The genes are very tightly packed with as little as two nucleotides between the rpl14 and rpl24 genes. The gene arrangement is very similar to that reported for the rhodophyte alga, Porphyra purpurea, and the chromophyte diatom, Odontella sinensis, indicating a close evolutionary relationship between these groups of algae. Northern analysis indicates that the 29 genes are arranged as one operon and are transcribed as a single mRNA that is subsequently processed into smaller transcripts.

Time-dependent alteration of epidermal growth factor receptor in rat stomach by ethanol feeding

This study investigated the time-dependent effects of ethanol (EtOH) feeding on epidermal growth factor binding and epidermal growth factor-mediated functions in the stomach. Adult male rats were fed either an isocaloric control or EtOH-containing liquid diet (36% total calories as EtOH) for 2, 4 and 6 weeks. At the end of each feeding period, animals were sacrificed and the stomach was dissected for the sample preparation. EtOH caused a time-dependent alteration (r = 0.89) of the 125I-epidermal growth factor binding to the gastric mucosal membrane (% control: week 2, 114%; week 4, 64%* and week 6, 45%*, n = 5, *P < 0.05). Protein kinase analysis also showed that EtOH caused a time-dependent decrease of epidermal growth factor-stimulated autophosphorylation of epidermal growth factor receptor protein (180 kDa) during three feeding periods. Western blot analysis, using anti-tyrosine phosphorylated epidermal growth factor receptor (active form) antibody, revealed a major immunoreactive protein band (180 kDa) in all samples pre-incubated with 1 microM epidermal growth factor. Consistent with data from kinase analysis, treatment of EtOH decreased the immunoreactivity of the active form of epidermal growth factor receptor (180 kDa) in the stomach. In conclusion, EtOH feeding caused a time-dependent alteration of epidermal growth factor receptor in the stomach, which may be one of the mechanisms underlying the gastric pathology associated with alcohol abuse.

Purification and characterization of two bifunctional chitinases/lysozymes extracellularly produced by Pseudomonas aeruginosa K-187 in a shrimp and crab shell powder medium

Two extracellular chitinases (FI and FII) were purified from the culture supernatant of Pseudomonas aeruginosa K-187. The molecular weights of FI and FII were 30,000 and 32,000, respectively, by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and 60,000 and 30,000, respectively, by gel filtration. The pIs for FI and FII were 5.2 and 4.8, respectively. The optimum pH, optimum temperature, pH stability, and thermal stability of FI were pH 8, 50 degrees C, pH 6 to 9, and 50 degrees C; those of FII were pH 7, 40 degrees C, pH 5 to 10, and 60 degrees C. The activities of both enzymes were activated by Cu2+; strongly inhibited by Mn2+, Mg2+, and Zn2+; and completely inhibited by glutathione, dithiothreitol, and 2-mercaptoethanol. Both chitinases showed lysozyme activity. The purified enzymes had antibacterial and cell lysis activities with many kinds of bacteria. This is the first report of a bifunctional chitinase/lysozyme from a prokaryote.

Transcriptional induction of cholesterol 7alpha-hydroxylase by dexamethasone in L35 hepatoma cells requires sulfhydryl reducing agents

It is known that hepatic levels of reduced glutathione correlate with the activity of the liver-specific enzyme cholesterol-7alpha-hydroxylase. We examined the possibility that sulfhydryl reducing agents activate transcription of cholesterol 7alpha-hydroxylase. Adding dithiothreitol (DTT, 1 mM) and dexamethasone to L35 hepatoma cells increased the content of 7alpha-hydroxylase mRNA 3-fold above the levels observed with dexamethasone alone. Without dexamethasone, DTT had no affect. The addition of reduced glutathione to L35 cells demonstrated a similar potentiation of expression dependent on dexamethasone. Nuclear run-on assays showed that in the presence of both dexamethasone and DTT, the transcription of the 7alpha-hydroxylase gene was clearly increased. In contrast, by itself, dexamethasone did not cause a detectable increase in the transcription of the 7alpha-hydroxylase gene. Dexamethasone and DTT did not affect the transcription of beta-actin, suggesting a selective induction of the 7alpha-hydroxylase gene. DTT reversed repression of 7alpha-hydroxylase expression by insulin but not the repression by phorbol ester. Our data show for the first time that the sulfhydryl redox potential of the hepatocyte (i.e. level of reduced glutathione) has a marked influence on the transcription and expression of the liver-specific gene 7alpha-hydroxylase.

Chronic ethanol feeding alters the structure and function of the epidermal growth factor receptor in rat stomach

We investigated the effect of chronic ethanol feeding on the EGF receptor in rat stomach. Adult male rats were fed either an isocaloric control or ethanol (EtOH)-containing liquid diet (36% total calories as EtOH) for 4 weeks EtOH significantly reduced the specific binding of 125I-EGF to the gastric mucosal membrane (control vs. EtOH, 2.07 +/- 0.2 vs. 0.94 +/- 0.16 fmol/mg protein; p < 0.01). Scatchard analysis suggested that the lower binding might be due to the reduction of EGF receptor number, and/or the affinity of the high-affinity binding site. Western blot analysis, using anti-EGF receptor antibody, revealed four immunoreactive protein bands (180, 150, 60, and 50 kDa) in the lectin-purified gastric membrane prepared from both groups. However, the intensities of these protein bands in the EtOH-fed animals were 90% lower compared to the controls. In the EGF-responsive protein kinase assay, 32P-ATP was incubated with lectin-purified samples in the absence or presence of 1 microM EGF. EGF stimulated autophosphorylation of the EGF receptor (180 kDa) in stomach from the control groups, but not the EtOH-fed animals. This EtOH-related alteration of the gastric EGF receptor may be one of the mechanisms underlying the gastric pathology associated with alcohol abuse.

Histopathologic alterations of periodontium in cyclosporin-treated rats. Is the periodontium a target tissue for the drug?

Gingival dimensions and histopathologic alterations in periodontium were examined in rats continuously exposed to cyclosporin-A (CSA). 60 male Sprague-Dawley rats were divided into 2 groups. Rats in the test group daily received CSA in mineral oil by gastric feeding at a dosage of 30 mg/kg body weight for 6 weeks. Rats in the control group received mineral oil only. 10 rats from each group were sacrificed at 2-week intervals. Gingival dimensions were assessed from stone models obtained from the maxillary and mandibular incisal regions. Horizontal, sagittal and frontal tissue sections were obtained from these regions as well. Gingival dimensions in the mandibular and maxillary incisal regions were significantly increased in rats exposed to CSA. Light-microscopic observations revealed a granulation tissue formation at tooth-gingiva interface and an irregular bony surface on dental alveoli in experimental animals. Because both soft and hard tissue of periodontium in experimental rats being significantly effected by CSA compared to control animals, we hypothesized that the periodontium is a target tissue for CSA.

Formation of morphine from codeine in Chinese subjects of different CYP2D6 genotypes

Codeine and morphine pharmacokinetics among different CYP2D6 genotypes was compared in this study. Polymerase chain reaction tests were used to determine CYP2D6 genotypes in leukocyte deoxyribonucleic acid in 32 unrelated volunteers. Based on the genotypes, subjects were categorized into three groups: homozygous C/C188 (n = 8), heterozygous C/T188 (n = 12), and homozygous T/T188 (n = 12). Each subject was given a single oral dose of 30 mg codeine phosphate tablet after overnight fasting. Plasma concentration of codeine and 24-hour urinary morphine recovery were measured with HPLC. All three genotypes of subjects showed almost identical time profiles of plasma codeine. Urinary morphine glucuronide was hydrolyzed with beta-glucuronidase. The total recovered amount of morphine and glucuronides was 4349 +/- 646, 2564 +/- 242, and 1127 +/- 164 nmol (mean +/- SEM), respectively, for C/C188, C/T188, and T/T188 subjects (p < 0.05). The significant lower amount of urinary morphine but identical codeine plasma concentration suggested a lower partial clearance of the formation of morphine from codeine in T/T188 subjects. The results suggest a future study to assess the analgesic effect of codeine in different genotypes of CYP2D6 extensive metabolizers.

[Medullary mechanism of the inhibition on renal sympathetic efferent activities by stimulation of the cervical vagal afferent nerve in rabbits]

Experiments were performed on 63 rabbits anesthetized with pentobarbital, paralyzed with gallamine triethiodide and ventiled artifically. Ipsilateral renal sympathetic nerve discharge (RSND), unit discharges of rostral ventrolateral medulla (RVL), caudal ventrolateral medulla (CVL) and blood pressure (BP) were recorded. The sympatho-inhibitory response were evoked by stimulation of the central end of vagal nerve (CVN) (731/788 exp.). The inhibitory duration is 3.6 +/- 0.185 s. The responses vary with the functional state of the CNS. The RSND inhibitory duration could be shortened or prolonged, depending on the excitatory background of RSND or the basal sympathetic tonic activity. The results indicate that CVN-induced inhibitory of RSND may be mediated, at least partly, by excitation of NTS and CVL, which results, in turn, in depressing RVL and final reduction of sympathetic efferent activity.

International variations in cardiovascular mortality associated with diabetes mellitus: the WHO Multinational Study of Vascular Disease in Diabetes

The WHO Multinational Study of Vascular Disease in Diabetes was launched in 1975-77 to investigate international variations in the occurrence of different manifestations of vascular disease in subjects with insulin-dependent and non-insulin-dependent diabetes. A morbidity and mortality follow-up extending until January 1, 1988 was carried out in 10 centres, including five European centres (London, Switzerland, Berlin, Warsaw and Zagreb), two East Asian centres (Hong Kong and Tokyo), two Native American centres (Arizona and Oklahoma) and one Caribbean centre (Havana). Of a total of 4714 diabetic subjects (2310 men and 2404 women) aged between 35 and 55 years at baseline who were successfully followed up, 1266 were classified as having insulin-dependent diabetes and 3448 as having non-insulin-dependent diabetes. There was a large variation between the centres in ischaemic heart disease and cerebrovascular disease mortality rates for both insulin-dependent and non-insulin-dependent diabetic subjects, presumably reflecting in part differences between the background populations in mortality rates from these cardiovascular causes. The lowest ischaemic heart disease mortality rates for diabetic subjects were observed in Hong Kong and Tokyo centres, representing industrialized countries which have continued to have low ischaemic heart disease mortality rates. The importance of raised blood pressure and proteinuria as potentially modifiable cardiovascular risk factors in diabetic subjects was confirmed in this study.

Epidermal growth factor in gingival crevicular fluid and its binding capacity in inflamed and non-inflamed human gingiva

Epidermal growth factor (EGF) is a pro-inflammatory small peptide (6000 Da) with a variety of biological activities including stimulation of cell differentiation and mediation of proteolysis by binding to its specific receptor on the cell surface. The purpose of this study was to determine the levels of EGF in gingival crevicular fluid (GCF) and the EGF-binding capacity to its receptor in gingival tissue. The GCF samples were collected from six patients by inserting paper strips into shallow (< 5 mm) and deep pockets (> or = 5 mm) for 30 s. The strips were soaked in 0.2 M acetate for extraction and the EGF in the supernatants was analysed by radioimmunoassay. To determine the binding capacity of EGF to its receptor, inflamed gingival tissues (pocket depth > or = 5 mm, Gingival Index = 1, 2 or 3) were collected during periodontal flap surgery and non-inflamed gingival tissues (pocket depth < 5 mm, Gingival Index = 0) were collected during surgical "crown lengthening' for aesthetic purposes. The tissues were pooled by group, homogenized for membrane preparation and the supernatants obtained after centrifugation were used in a 125IEGF binding assay. To determine the effect of inflammation on gingival EGF receptor, inflamed and non-inflamed gingival tissues were collected from six patients and prepared similarly to the binding assay. Gingival preparations were then electrophoresed for Western blot analysis with EGF receptor antiserum. The EGF level in GCF was significantly lower (P < 0.05) in the samples collected from pockets > or = 5 mm (0.9 +/- 0.6 ng/ml) than in those from pockets < 5 mm (2.4 +/- 2.1 ng/ml). The average Gingival Index was higher (2.6 +/- 0.6) in pockets > or = 5 mm than in pockets < 5 mm (1.4 +/- 1.0). Specific binding of 125I-EGF to its receptor in inflamed gingiva was 2.7-fold higher than in non-inflamed gingiva (14.4 +/- 4.9 vs 5.4 +/- 1.8 fmol/g wet tissue). Western blot analysis showed two major immunoreactive bands (180 and 120 kDa), which represent EGF receptor and its degradation products, in inflamed gingiva. The findings show that inflammation activates EGF binding capacity in gingiva and that the up-regulation of EGF receptor in inflamed gingiva might be associated with a lowered concentration of EGF in GCF produced adjacent to inflamed gingiva. This up-regulation of EGF receptor during inflammation might be an important mechanism in the pathogenesis of periodontal disease.

Cyclosporin A-induced gingival overgrowth in rats: macroscopic and microscopic observations

Because the existence of cyclosporin A-induced gingival overgrowth in animals has not been well established, a pilot study was undertaken to determine whether such gingival overgrowth could be observed in Sprague-Dawley rats. Thirty-six male rats, age 6 weeks, were randomly divided into two groups. The test group was given 30 mg/kg of body weight of cyclosporin A daily by gastric feeding. The control group was given mineral oil instead. Stone casts of the gingiva in the mandibular incisor region were made biweekly for 6 weeks. The three-dimensional growth pattern-the buccolingual width, the mesiodistal width, and the vertical height of the gingiva-was analyzed on the casts. The animals were killed after the last impression was taken, and tissue sections were made. Stereomicroscopy revealed marked overgrowth of the gingiva in the test rats. All three-dimensional measurements on the stone casts were greater in the test group, beginning 2 weeks after cyclosporin A was given. Histologically the overgrowth of the epithelia and connective tissue was easily confirmed in the buccal and lingual gingiva of the test rats.

Translocation of apolipoprotein B across the endoplasmic reticulum is blocked in abetalipoproteinemia

Abetalipoproteinemia (ABL) is an autosomal recessive disease characterized by the inability of the liver and intestine to secrete apolipoprotein B (apoB). Mutations in the microsomal triglyceride transfer protein (MTP) gene, but not the apoB gene, are responsible for the ABL phenotype. It is not clear how loss of MTP in ABL patients leads to a complete, but specific, block in the secretion of apoB. It is to this question that our work is directed. In cultured cells lacking MTP, translocation of apoB is completely arrested, leading to the hypothesis that apoB requires MTP in order to completely enter the lumen of the endoplasmic reticulum, the site of lipoprotein assembly. We examined this hypothesis by determining the presence in plasma of distinct N-terminal apoB peptides, produced exclusively from translocation arrested apoB, in the plasma of six ABL patients and six normal subjects. The data show that N-terminal apoB peptides are present in the plasma of six ABL patients, whereas intact apoB-100 was barely detectable. Moreover, the plasma of all six ABL patients displayed a 2000-fold increase in the amount of an 85 kDa N-terminal apoB peptide relative to apoB-100. These data provide the first in vivo data supporting the essential role that MTP plays in apoB translocation. In normal humans, varied expression of MTP may be responsible for the post-transcriptional regulation of apoB secretion.

Detection of epidermal growth factor receptor in inflammatory periapical lesions

Epithelial cell proliferation is often observed in periapical lesions of endodontic origin. The mechanisms which stimulate the epithelial cell rests of Malassez to proliferate are not understood fully. Fifteen inflammatory periapical lesions (10 granulomas and five cysts) obtained from periapical surgery and six additional periapical lesions (four granulomas and two cysts) collected from extracted teeth were examined using immunohistochemical staining and 125I-EGF (epidermal growth factor) binding assay to detect the presence of epidermal growth factor receptor. The results indicated that the periapical lesions without epithelial cell proliferation had a weak immunoperoxidase staining or low specific binding of 125I-EGF. In contrast, the periapical lesions with epithelial cell proliferation and cyst formation exhibited a strong immunoperoxidase staining in the epithelial cells or high specific binding of 125I-EGF.

Excess mortality and its relation to hypertension and proteinuria in diabetic patients. The world health organization multinational study of vascular disease in diabetes

OBJECTIVE

To determine the extent that mortality in IDDM and NIDDM patients is in excess of that of the general population and examine its relation to hypertension and proteinuria in diabetic patients.

RESEARCH DESIGN AND METHODS

A stratified random sample of 4,714 diabetic patients aged 35-55 years participating in the World Health Organization Multinational Study of Vascular Disease in Diabetes has been followed up from 1975 to 1987. Excess mortality, compared with the background population, was assessed in terms of standardized mortality ratios (SMRs) for each of the 10 international cohorts. The relationship between excess mortality and proteinuria/hypertension was examined by diabetes type and sex.

RESULTS

SMRs were in general higher in patients with IDDM (ranging from 188 to 686 for men and from 336 to 790 for women) than with NIDDM (from 138 to 370 for men and from 126 to 435 for women). For both diabetes types and in both sexes, SMRs decreased with increasing age and increased with increasing diabetes duration. Patients with both hypertension and proteinuria experienced a strikingly high mortality risk: 11-fold for men with IDDM and 18-fold for women with IDDM and 5-fold for men with NIDDM and 8-fold for women with NIDDM. Even in the absence of proteinuria and hypertension, SMRs were significantly increased in both IDDM (284 men and 360 women) and NIDDM (192 men and 236 women) patients.

CONCLUSIONS

Considerable international differences were found not only in mortality rates for the two types of diabetes but also in the extent of excess mortality among centers. IDDM patients had a high excess mortality in comparison with the general population. The significant excess mortality was demonstrated even in patients without proteinuria and without hypertension for both sexes and diabetes types.