Ecological analysis of collectivity of alcohol consumption in England: importance of average drinker

OBJECTIVE

To assess whether the average consumption of alcohol is associated with the prevalence of heavy drinking, problem drinking, and abstention in England.

DESIGN

Ecological analysis using data from a cross sectional household based survey of English adults.

SUBJECTS

Random sample of 32,333 adults from the English population who participated in the 1993 and 1994 health surveys for England.

MAIN OUTCOME MEASURES

Association, expressed as the correlation coefficient, between the regional mean and median alcohol consumption and the regional prevalence of heavy drinking, problem drinking, and abstention.

RESULTS

Mean consumption of alcohol in light to moderate drinkers was strongly positively associated with the prevalence of heavy drinking (r = 0.75 in men and r = 0.62 in women for drinking more than 21 and 14 units per week respectively). A similar association was found between median consumption and prevalence of heavy drinking. Abstention was not significantly associated with mean consumption in drinkers (r = 0.08 for men and r = -0.29 for women). Both the median and mean consumption in drinkers were positively associated with the prevalence of problem drinking as defined by the CAGE questionnaire on alcohol use (r = 0.53 for men and r = 0.42 for women for the association with mean consumption).

CONCLUSION

Factors that increase the average consumption of alcohol in the population may result in an increase in the prevalence of heavy drinking and related problems.

TGFbeta1 regulates gene expression of its own converting enzyme furin

TGFbeta1 is known for its potent and diverse biological effects, including immune regulation, and cell growth and differentiation. We have recently shown that TGFbeta1 precursor is processed by human furin COOH-terminal to the R-H-R-R278 cleavage site to generate authentic mature TGFbeta1. In the present study, we demonstrate that steady-state furin mRNA levels are increased in rat synovial cells by 2 and 20 ng/ml TGFbeta1. Stimulation with TGFbeta1 results in a significant increase in furin mRNA levels, starting at 3 h with the peak effect observed at 12 h (2.5-fold increase +/-0.4). TGFbeta1 did not increase furin mRNA stability, and treatment of synovial cells with actinomycin D, before TGFbeta1 addition prevented the increase in fur gene expression, suggesting that the observed regulation occurs at the level of gene transcription. Treatment of synovial and NRK-49F fibroblastic cells with exogenous TGFbeta1 (5 ng/ml) or TGFbeta2 (10 ng/ml) translates into an increase in pro-TGFbeta1 processing as evidenced by the appearance of a 40-kD immunoreactive band corresponding to the TGFbeta1 NH2-terminal pro-region. Furin processing activity stimulated by TGFbeta2 correlates with significant increase in extracellular mature and heat-activable TGFbeta1 as determined by an isoform-specific ELISA assay. Taken together, these results demonstrate for the first time that TGFbeta1 upregulates gene expression of its own converting enzyme, and that this expression is translated into augmented processing of the TGFbeta1 precursor form. Such adaptive responsiveness of the TGFbeta1 convertase may represent an important aspect of TGFbeta1 bioavailibility in TGFbeta1-related processes and pathological conditions.

Cellular localization of the prohormone convertases in the hypothalamic paraventricular and supraoptic nuclei: selective regulation of PC1 in corticotrophin-releasing hormone parvocellular neurons mediated by glucocorticoids

The prohormone convertases (PCs) are processing enzymes that activate proproteins via cleavage at specific single or pairs of basic residues. The hypothalamic paraventricular nucleus (PVN) and supraoptic nucleus (SON) are primary sites of biosynthesis of several neuroendocrine hormone precursors, including provasopressin (pro-AVP), pro-oxytocin (pro-OT), and procorticotrophin-releasing hormone (pro-CRH), which require post-translational processing to yield active products. Using in situ hybridization, we observed PC1 and PC5 mRNAs in PVN and SON magnocellular neurons, while PC2 mRNA was observed in both magnocellular and parvocellular PVN neurons as well as magnocellular SON neurons. Similar to furin, PC7 mRNA was expressed throughout the PVN and SON, whereas PACE4 mRNA levels were undetectable. Both immunohistochemical and Western blot studies were performed to demonstrate the presence of PC proteins and forms in the PVN and SON. Using double-labeling in situ hybridization, we examined the cellular colocalization of each PC mRNA with pro-AVP, pro-OT, and pro-CRH mRNAs in PVN and SON. PC1 mRNA was colocalized with both AVP and OT mRNA in PVN and SON magnocellular neurons. All AVP, OT, and CRH neurons expressed PC2. In contrast, PC5 mRNA was colocalized only with OT mRNA. We examined the effects of adrenalectomy (ADX) on PVN PC mRNA levels. PC1 mRNA levels were increased selectively within CRH/AVP parvocellular neurons but were unchanged in PVN magnocellular AVP or OT neurons. These results established the anatomical organization of each convertase and proneuropeptide substrates in the PVN and SON and suggested potential roles for each enzyme under resting and stimulated conditions.

Lattice fringe continuity in the absence of crystal continuity in enamel

Since high-resolution transmission electron microscopy (HRTEM) provides information on a nearly atomic level, the confidence level with this method is very high. Thus, when lattice fringe continuity is found between two enamel crystals in proximity, such continuity has been taken as evidence of crystal fusion (Daculsi and Kerebel, 1977). Similarly, selected-area dark-field (SADF) electron microscopic imaging has been used to study the axial and spatial orientation of crystals. These studies have shown that there is apparent continuity between enamel and dentin crystals (Arsenault and Robinson, 1989). This observation supported the hypothesis that enamel crystallites are initiated by crystallites in dentin. We have used both HRTEM and SADF methods to identify instances of spatial relationship between crystallites in sections of rat incisor enamel and shark enameloid. In each instance of apparent continuity, goniometric tilting was used to examine the continuous interface. All instances where two crystallites seemed to come into contact, and where HRTEM imaging showed the lattice fringes to be directly continuous, were separated into individual crystallites when the specimen was tilted a few degrees. Thus, adjacent crystallites can show lattice fringe continuity in the absence of real crystallite contact. When instances of overlapping crystallites were examined by SADF imaging, the overlapping crystallites gave a single bright image. Goniometric tilting revealed separate crystallites. Thus, neither lattice fringe continuity nor image continuity under SADF can be used as evidence of crystal continuity unless goniometric rotation and tilting are applied when spatial relationships are suspected.

Arsenic induces overexpression of growth factors in human keratinocytes

Although epidemiological studies have shown that inorganic arsenicals are human skin carcinogens and induce hyperproliferation and hyperkeratosis, there is currently no known mechanism for their action or an established animal model for its study. We observed increased mRNA transcripts and secretion of keratinocyte growth factors, including granulocyte macrophage-colony stimulating factor (GM-CSF) and transforming growth factor-alpha (TGF alpha) and the proinflammatory cytokine tumor necrosis factor-alpha in primary human epidermal keratinocytes cultured in the presence of low micromolar concentrations of sodium arsenite. Treatment with sodium arsenite resulted in a significant increase in cell proliferation, as indicated by increases in cell numbers, c-myc gene expression, and incorporation of [3H]thymidine into cellular DNA. Studies of transcriptional regulation indicate that the rate of GM-CSF mRNA transcription is increased, while the elevated TGF alpha is likely the results of message stabilization. While a number of cytokine regulatory networks exist in the skin, studies utilizing neutralizing antibodies against the growth factors of interest indicate that inhibition of the arsenic-induced increase in TGF alpha results in a corresponding decrease in the gene expression and secretion of GM-CSF. The present studies demonstrate that growth-promoting cytokines and growth factors are induced in keratinocytes following treatment with arsenic and could play a significant role in arsenic-induced skin cancer.

[Factors influencing long-term survival in patients with nonoperable lung cancer: an analysis by Cox model]

This paper reports a prospective survey of 173 patients with nonoperable lung cancer between January. 1, 1983 to March. 1, 1985. The follow-up rate was 97.7% over five years. Fourteen factors including sex, age, course of disease before treatment, clinical stage, performance status, size of mass, metastatic status, hemoglobin before treatment, short-term response to treatment and so on which might influence long term survival were studied by univariate analysis (Kruskal-Wallis test for Kaplan-Meier survival curve) and by multivariate analysis (Cox's proportional hazad model and audio-visual chart test for goodness of fit). Multivariate analysis using Cox's model revealed 6 significant prognostic factors: performance status, short-term response to treatment, clinical stage, hemoglobin before treatment, smoking index and method of treatment. The survival prediction equation was chi 2 = 72.14, nu = 6, P < 0.0001. The results indicate that the performance status and the CR rate of the initial treatment, among other things, is the major factors affecting prognosis.

Role of endotoxin in tumor necrosis factor alpha expression from alveolar macrophages treated with urban air particles

The effects of urban air and diesel particles on inflammatory cytokine gene expression, tumor necrosis factor alpha (TNF-alpha) in particular, were studied in rat alveolar macrophages. TNF-alpha, interleukin (IL)-1, IL-6, cytokine-induced neutrophil chemoattractant (CINC), and macrophage inflammatory protein (MIP)-2 gene expression and TNF-alpha secretion were increased in cells treated with 50 to 200 micrograms/mL of urban air particles in a concentration-related manner. There was no cytokine induction by diesel particles at any of the concentrations tested. Cytokine expression was not related to reactive oxygen species since antioxidants, such as catalase, TMTU, or DMSO, had no effect on TNF-alpha secretion. However, cytokine induction by urban air particles was completely prevented by polymyxin B, an antibiotic capable of neutralizing bacterial lipopolysaccharide (LPS) activities. Furthermore, LPS was detected on the urban air particles, but not on diesel particle. These results suggest that activation of cytokine gene expression and secretion in rat alveolar macrophages by urban air particles is due to the presence of endotoxin on the particles.

Effects of mycotoxins on cytokine production and proliferation in EL-4 thymoma cells

The thymoma cell line EL4.IL-2 (EL-4) was used as a T-cell model to assess the immunotoxic effects of several mycotoxins produced by the Aspergillus-Penicillium and the Fusarium groups. EL-4 cells were stimulated with phorbol 12-myristate 12-acetate (PMA) in the presence of mycotoxins at various concentrations for 5 d and culture supernatants were analyzed for interleukins (IL) IL-2 and IL-5 by enzyme-linked immunosorbent assay (ELISA). The cytokine effects were further related to proliferation and cell viability using the MTT [3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide] assay with absorbance at 570 nm (A570) as the endpoint indicator. IL-2 and IL-5 levels were dramatically increased by cyclopiazonic acid at 50-1000 ng/ml, whereas IL-2 was significantly decreased at 10 microgram/ml. Proliferation was slightly increased at 100-1000 ng/ml cyclopiazonic acid but markedly depressed at 5 and 10 microgram/ml. When EL-4 cells were exposed to 5 and 10 microgram/ml of ochratoxin A, IL-2 production was markedly increased while IL-5 production was significantly decreased. The A570 was significantly decreased by ochratoxin A at 10 microgram/ml. IL-2 and Il-5 production was almost totally suppressed by patulin at concentrations > or = 500 ng/ml and by T-2 toxin at > or = 5 ng/ml. These effects occurred concurrently with marked depression of A570 in the MTT assay. Although A570 was unaffected by either zearalenone or alpha-zearalenol exposure, both IL-2 and IL-5 levels were significantly elevated by these toxins at 5 or 10 microgram/ml. IL-2 and IL-5 production were not affected in EL-4 cells cultured with either the Aspergillus-Penicillium toxins aflatoxin B1 and secalonic acid or the Fusarium toxins wortmannin, fumonisin B1, or fusaric acid at concentrations up to 10 microgram/ml. In total, the EL-4 culture studies indicated that cyclopiazonic acid, ochratoxin A, zearalenone, and alpha-zearalenol could stimulate cytokine production whereas patulin and T-2 toxin were inhibitory. Cytokine dysregulation was not always related directly to perturbations in proliferation. The results suggest that the EL-4 thymoma cell line could be a simple and effective in vitro model for evaluating immunotoxicity of various classes of environmental chemicals.

cDNA structure, tissue distribution, and chromosomal localization of rat PC7, a novel mammalian proprotein convertase closest to yeast kexin-like proteinases

By using reverse transcription-coupled PCR on rat anterior pituitary RNA, we isolated a 285-bp cDNA coding for a novel subtilisin/kexin-like protein convertase (PC), called rat (r) PC7. By screening rat spleen and PC12 cell lambda gt11 cDNA libraries, we obtained a composite 3.5-kb full-length cDNA sequence of rPC7. The open reading frame codes for a prepro-PC with a 36-amino acid signal peptide, a 104-amino acid prosegment ending with a cleavable RAKR sequence, and a 747-amino acid type I membrane-bound glycoprotein, representing the mature form of this serine proteinase. Phylogenetic analysis suggests that PC7 represents the most divergent enzyme of the mammalian convertase family and that it is the closest member to the yeast convertases krp and kexin. Northern blot analyses demonstrated a widespread expression with the richest source of rPC7 mRNA being the colon and lymphoid-associated tissues. In situ hybridization revealed a distinctive tissue distribution that sometimes overlaps with that of furin, suggesting that PC7 has widespread proteolytic functions. The gene for PC7 (Pcsk7) was mapped to mouse chromosome 9 by linkage analysis of an interspecific backcross DNA panel.

Molecular basis of alpha-methyltryptophan resistance in amt-1, a mutant of Arabidopsis thaliana with altered tryptophan metabolism

A mutant of Arabidopsis thaliana, amt-1, was previously selected for resistance to growth inhibition by the tryptophan analog alpha-methyltryptophan. This mutant had elevated tryptophan levels and exhibited higher anthranilate synthase (AS) activity that showed increased resistance to feedback inhibition by tryptophan. In this study, extracts of the mutant callus exhibited higher AS activity than wild-type callus when assayed with either glutamine or ammonium sulfate as amino donor, thus suggesting that elevated AS activity in the mutant was due to an alteration in the alpha subunit of the enzyme. The mutant also showed cross-resistance to 5-methylanthranilate and 6-methylanthranilate and mapped to chromosome V at or close to ASA1 (a gene encoding the AS alpha subunit). ASA1 mRNA and protein levels were similar in mutant and wild-type leaf extracts. Levels of ASA1 mRNA and protein were also similar in callus cultures of mutant and wild type, although the levels in callus were higher than in leaf tissue. Sequencing of the ASA1 gene from amt-1 revealed a G to A transition relative to the wild-type gene that would result in the substitution of an asparagine residue in place of aspartic acid at position 341 in the predicted amino acid sequence of the ASA1 protein. The mutant allele in strain amt-1 has been renamed trp5-1.

Evaluation of isofagomine and its derivatives as potent glycosidase inhibitors

A pseudo-aza-monosaccharide and several pseudo-aza-disaccharide compounds were constructed based on replacement of the anomeric carbon with a nitrogen and the ring oxygen with a carbon. The inhibition constants of these compounds toward five different glycosidases, alpha-glucosidase, beta-glucosidase, isomaltase, alpha-mannosidase, and glucoamylase, were obtained. Isofagomine, the pseudo-aza-monosaccharide, shows a broad spectrum of strong inhibition against glycosidases. It is the most potent inhibitor of beta-glucosidase from sweet almonds reported to date and also a strong inhibitor of glucoamylase, isomaltase, and alpha-glucosidase. Isofagomine inhibits beta-glucosidase, glucoamylase, and isomaltase more strongly than 1-deoxynojirimycin where the ring oxygen has been replaced with a nitrogen. The alpha-1,6- linked pseudo-disaccharide showed very strong inhibition toward glucoamylase, being nearly as potent an inhibitor as acarbose. Pseudo-disaccharides in which the anomeric nitrogen was methylated to favor formation of either the alpha or beta substrate linkage generally had weakened inhibition for the glycosidases studied most likely due to steric interference with the various active sites. These results indicate that the presence of a basic group at the anomeric center is important for carbohydrase inhibition. The presence of a charged carboxylate group near the anomeric carbon which interacts with the basic nitrogen is suggested for these enzymes, particularly for beta-glucosidase. The presence of a second alpha-linked glucosyl residue is also critical for strong inhibition of glucoamylase.

Kinetic studies of calcium binding to the regulatory site of troponin C from cardiac muscle

We have studied the kinetics of the structural transitions induced by calcium binding to the single, regulatory site of cardiac troponin C by measuring the rates of calcium-mediated fluorescence changes with a monocysteine mutant of the protein (C35S) specifically labeled at Cys-84 with the fluorescent probe 2(-)[4'-(iodoacetamido)anilino]naphthalene-6-sulfonic acid. At 4 degrees C, the binding kinetics determined in the presence of Mg2+ was resolved into two phases with positive amplitude, which were completed in less than 100 ms. The rate of the fast phase increased linearly with [Ca2+] reaching a maximum of approximately 590 s-1, and that of the slow phase was approximately 100 s-1 and did not depend on Ca2+ concentration. Dissociation of bound Ca2+ from the regulatory site occurred with a rate of 102 s-1, whereas the dissociation from the two high affinity sites was about two orders of magnitude slower. These results are consistent with the following scheme for the binding of Ca2+ to the regulatory site: [formula: see text] where the asterisks denote states with enhanced fluorescence. The apparent second-order rate constant for calcium binding is Kok1 = 1.4 x 10(8) M 1 s-1. The two first-order transitions occur with observed rates of k1 + kappa-1 approximately 590 s-1 and kappa 2 + kappa-2 approximately 100 s-1, and the binding of Ca2+ to the regulatory site is not a simple diffusion-controlled reaction. These transitions provide the first information on the rates of Ca(2+)-induced conformational changes involving helix movements in the regulatory domain.

Expression of mRNA for somatostatin receptor (sstr) types 2 and 5 in individual rat pituitary cells. A double labeling in situ hybridization analysis

To characterize cell specific expression of sstr subtypes in the pituitary we have analyzed mRNA for sstr1-5 in rat pituitary somatotrophs by reverse transcriptase polymerase chain reaction and determined the pattern and level of expression of mRNA for sstr subtypes 2 and 5 in individual pituitary cell subpopulations by double label in situ hybridization. Purified somatotrophs expressed mRNA for all 5 sstrs. In situ hybridization analysis revealed sstr5 mRNA in 70% of somatotrophs, 57% of thyrotrophs, 38% of corticotrophs, 33% of lactotrophs, and 21% of gonadotrophs. mRNA for sstr2 occurred in 40% of somatotrophs, 36% of thyrotrophs, 26% of lactotrophs, 3% of corticotrophs, and 8% of gonadotrophs. Not only were more cells positive for sstr5 mRNA but the average number of autoradiographic grains/cell was also higher for sstr5 than sstr2. These results show expression of multiple sstr genes in individual pituitary cells. mRNA for sstr2 and 5 occur in each of the 5 major pituitary cell subsets, sstr5 mRNA being more widely and more abundantly expressed than sstr2.

[Motoneuronal death following prevention of reinnervation during postnatal development]

The hypothesis that survival of motoneurons depends on targets postnatally was tested in Wistar rats of known age. Under ether anesthesia, the cut distal end of a medial gastrocnemius (MG) nerve was anchored to the lateral gastrocnemius (LG) muscle to prevent reinnervation. The compound action potential (CAP) in response to stimulation of the MG nerve was recorded from L4 and L5 ventral roots to evaluate the degree of motoneuronal death in the nerve. CAPs of MG nerves were greatly reduced 1 to 8 months after the operation in the rats operated on at 6 or 9 days of age, which indicates that the majority of MG motoneurons died after the operation. In contrast, the CAPs in the animals which were operated on at older than 12 days were similar to normal animals. However, the number of motor units that remained in the implanted MG nerve was 1.3 on the average in the rats operated on at 12-days-old. In normal rats, it was 87. Thus, the results indicate that in the rats operated on at 12 days of age, a majority of MG motoneurons survived without making functional synapses. We conclude that there is a sharp critical period, between 9 and 12 days after birth, during which motoneuronal target dependency changes.

Mortality study of construction workers in the UK

BACKGROUND

Construction is one of the most dangerous industries in the world. However, there has been little literature on occupational epidemiology in this field. A study of the mortality experience over a 13-year period among construction workers in the UK was carried out.

METHOD

This was based on 15,007 death certificates of members of the Building and Civil Engineering Holiday and Benefit Scheme, who had died during 1975 to 1987 aged 20-64 years. Proportional mortality ratio (PMR) and mortality odds ratio techniques were used.

RESULTS

Significantly elevated PMR were found for deaths from all cancers, including cancer of the lung and stomach, and for accidental deaths. Associations were demonstrated between several job categories and an increased risk of cancer mortality. Occupational exposures to hazardous substances may have contributed to the elevated cancer mortality, although the study findings should be interpreted with caution. Inadequate supervision of safety procedures, together with a high proportion of young and inexperienced workers, may be associated with the high number of accidental deaths.

CONCLUSIONS

The results support the hypothesis that working in the construction industry is associated with a high risk for accidental death and probably also for malignant diseases including lung, mesothelium and stomach cancers. Further epidemiological studies among construction workers are needed to support policies aimed at improving occupational health, including the prevention of accidents.

c-KIT expression enhances the leukemogenic potential of 32D cells

The growth of human leukemic cells in culture and in vivo is dependent upon the presence of hematopoietic growth factors. Most populations of human leukemic acute myeloblastic leukemia (AML) cells express c-Kit on their surface and respond to Kit ligand (KL) in culture. To determine if this interaction was of potential significance in vivo we used a mouse model system. 32D cells, a murine IL-3-dependent myeloid cell line, were rendered KL responsive by transfection of the murine c-Kit. After injection of 32D or 32D-Kit cells into syngeneic hosts, animals bearing 32D-Kit cells, but not 32D cells, became moribund and were killed. These animals had circulating leukemic blast cells, infiltration of bone marrow, spleen, brain, liver, lung, and kidney. Cells recovered from some of the animals continued to be dependent upon IL-3 or KL for growth while in other cases the cells were factor independent. This model illustrates that the constitutive expression of c-Kit enhances the leukemic potential of 32D cells. The model will be useful for studying the progression of leukemia in vivo and testing whether interruption of the interaction of Kit and KL can affect the growth of leukemic cells.

Matrix protein synthesis by glomerular mesangial cells in culture: effects of transforming growth factor beta (TGF beta) and platelet-derived growth factor (PDGF) on fibronectin and collagen type IV mRNA

The pathogenesis of glomerular scarring is multifactional; recent evidence suggests that transforming growth factor beta (TGF beta), a pleiotropic cicatricial mediator, may promote mesangial sclerosis by enhancing the production of extracellular matrix proteins. We studied the effect of TGF beta 1 and TFG beta 2 on collagen type IV and fibronectin (FN) synthesis in human glomerular mesangial cells in culture (GMC). Two hours after addition of TGF beta, an up to twofold increase in abundance of collagen type IV mRNA was found, which further increased up to fivefold within 24 h. Addition of cycloheximide did not inhibit the TGF beta effect, but caused by itself an up to twofold increase in the abundance of collagen type IV mRNA after 2 h. Together with collagen mRNA, the mRNA for FN and for platelet-derived growth factor (PDGF) was also enhanced. PDGF was found to enhance abundance of the collagen type IV and fibronectin mRNA in GMC. A neutralizing antibody to PDGF or a PDGF-antisense oligonucleotide partly inhibited the TGF beta-induced increase of collagen type IV mRNA, suggesting that TGF beta can affect the collagen type IV synthesis not only directly but also indirectly via the synthesis of PDGF.

The lef-3 gene of Autographa californica nuclear polyhedrosis virus encodes a single-stranded DNA-binding protein

The Autographa californica nuclear polyhedrosis virus (AcNPV) replicates in the nuclei of infected cells and encodes several proteins required for viral DNA replication. As a first step in the functional characterization of viral replication proteins, we purified a single-stranded DNA-binding protein (SSB) from AcNPV-infected insect cells. Nuclear extracts were chromatographed on single-stranded DNA agarose columns. An abundant protein with an apparent molecular weight of 43,000 was eluted from the columns at 0.9 to 1.0 M NaCl. This protein was not evident in extracts prepared from control cells, suggesting that the SSB was encoded by the virus. SSB bound to single-stranded DNA in solution, and binding was nonspecific with respect to base sequence, as single-stranded vector DNA competed as efficiently as single-stranded DNA containing the AcNPV origin of DNA replication. Competition binding experiments indicated that SSB showed a preference for single-stranded DNA over double-stranded DNA. To determine whether SSB was encoded by the lef-3 gene of AcNPV, the lef-3 open reading frame was cloned under the control of the bacteriophage T7 promoter. Immunochemical analyses indicated that LEF-3 produced in bacteria or in rabbit reticulocyte lysates specifically reacted with antiserum produced by immunization with purified SSB. Immunoblot analyses of infected cell extracts revealed that SSB/LEF-3 was detected by 4 h postinfection and accumulated through 48 h postinfection.

Failure to demonstrate a protein coat on enamel crystallites by morphological means

Phosphotungstic acid (PTA) treatment of section of Epon-embedded enamel dissolves the crystallites and stains material postulated to be crystal-bound proteins. Alternative, capillarity forces within the channels left after crystallite removal may draw in PTA. This prediction was tested on three systems. (1) Protein free synthetic hydroxyapatite was embedded in Epon; treatment of thin sections with PTA removed most crystals, leaving empty holes outlined by stain that could not represent protein. (2) Sections of rat incisor enamel were treated with PTA and then re-embedded in Epon and sectioned at 90 degrees to the original plane. In these sections-of-section the cut ends of dissolved crystallite profiles were coated with stain. To determine if stained protein coats can be detected in the absence of the crystallite profiles, Epon sections were partially demineralized with formic acid, re-embedded in Epon and sections-of section were PTA treated. Previously extracted crystallites left no stained coats, and only the crystallites that were not removed by formic acid left PTA-stained outlines. (3) PTA-treated sections of dogfish shark enameloid were flooded with 5-nm colloidal gold particles and sections-of-section were prepared. The presence of gold particles on the section surface and in holes previously occupied by crystallites suggested that PTA solution could also be sucked into similar holes. It is concluded that PTA outlines are not crystal-bound proteins but artefacts caused by stain lining holes left in the section when the crystallites have been extracted.

Distinct mRNA expression of the highly homologous convertases PC5 and PACE4 in the rat brain and pituitary

Posttranslational endoproteolysis is essential for the production of biologically active peptides from inactive precursors. Six kexin/substilisin-like endoproteases have been characterized in mammalian species. To understand the complex physiological functions of each convertase within a cellular context it is necessary to comprehensively define its tissue distribution and cohabitation with other members of the family. Previous studies demonstrated the distinct distribution of PC1, PC2, and furin mRNAs in the pituitary and brain, suggesting a unique function for each enzyme. In the present study, the mRNA tissue distributions of the two most recent and homologous members, PC5 and PACE4, were analyzed in rat pituitary and brain using in situ hybridization histochemistry. In the pituitary, the anterior lobe exhibited moderate levels of PC5 and high levels of PACE4 mRNAs. The intermediate lobe showed low levels of PC5 expression, while PACE4 mRNA levels were undetectable. PACE4 transcripts were detected throughout cells of the neural lobe suggesting expression in pituicytes. In the brain, PC5 expression was more restricted than PACE4. PC5 mRNA was detected only in neuronal cells, whereas PACE4 mRNA was expressed in both neuronal and glial cells. In areas that are rich in neuropeptides such as cortex, hippocampus, and hypothalamus, mRNA levels of PC5 were high but PACE4 were low or undetectable. In regions, such as the amygdaloid body and thalamus, distinct but complementary distributions of PC5 and PACE4 mRNAs were observed. The medial habenular and cerebellar Purkinje cells expressed very high levels of PACE4 mRNA. The present data strongly suggest unique tissue-specific functions of PC5 and PACE4.

[Determination of piperylpiperidine in wuwei qingzhuo powder by reversed phase HPLC]

A quantitative method has been developed for the determination of piperylpiperidine in Wuwei Qingzhuo powder by reversed phase HPLC. The average recovery is 102.0% (RSD = 0.46%) and lowest detection concentration 0.03 microgram/ml. The linear range of piperylpiperidine is 1.875-30 micrograms/ml, r = 0.9999.

The distinct gene expression of the pro-hormone convertases in the rat heart suggests potential substrates

The present study examined the distribution of the pro-hormone convertases PC1, PC2, furin, PACE4 and PC5 in the rat heart. Northern blot analysis of RNA extracted from cardiac tissues showed high levels of furin and PACE4 mRNA in the atria and ventricles, while PC5 mRNA was found to be expressed at high levels in the dorsal aorta. Although undetectable by Northern blot analysis, both PC1 and PC2 mRNA were detected by in situ hybridization and immunohistochemistry in discrete regions of the intracardiac para-aortic ganglia. In situ hybridization studies also showed that furin mRNA was observed in all cardiac tissues and cells, consistent with the previously reported ubiquitous expression of this gene. PACE4 mRNA was highly abundant in both the atria and ventricular cardiomyocytes, with low to undetectable levels observed in blood vessels. Finally, PC5 transcripts were expressed in the endothelial cells lining coronary vessels and the valve leaflets of the heart. The present localization studies in the heart and cardiac blood vessels suggests potential roles for each convertase in the processing of various neuropeptides, hormones and growth factors.

Changes in the serum concentrations of gonadotrophins and oestradiol in peripubertal Chinese Beijing black gilts

Four gifts of the Chinese Beijing Black breed, all from the same litter, had their blood serum concentrations of luteinizing hormone (LH), follicle stimulating hormone (FSH) and oestrogens (E2) measured by radioimmunoassay at intervals of 20 days between the ages of 5 and 185 days. The concentrations of LH declined sharply between days 5 to 25 and remained low until rising again from day 85 and reaching a peak at day 105 before declining again and remaining constant. The concentrations of FSH increased from day 85, peaking at day 105, followed by a slow decline to day 185. Serum E2 concentrations were high at day 5 then decreased dramatically, but increased considerably at 185 days. These results are similar to those reported from European breeds.

Co-activation of RanGTPase and inhibition of GTP dissociation by Ran-GTP binding protein RanBP1

RCC1 (the regulator of chromosome condensation) stimulates guanine nucleotide dissociation on the Ras-related nuclear protein Ran. Both polypeptides are components of a regulatory pathway that has been implicated in regulating DNA replication, onset of and exit from mitosis, mRNA processing and transport, and import of proteins into the nucleus. In a search for further members of the RCC1-Ran signal pathway, we have identified proteins of 23, 45 and 300 kDa which tightly bind to Ran-GTP but not Ran-GDP. The purified soluble 23 kDa Ran binding protein RanBP1 does not activate RanGTPase, but increases GTP hydrolysis induced by the RanGTPase-activating protein RanGAP1 by an order of magnitude. In the absence of RanGAP, it strongly inhibits RCC1-induced exchange of Ran-bound GTP. In addition, it forms a stable complex with nucleotide-free RCC1-Ran. With these properties, it differs markedly from guanine diphosphate dissociation inhibitors which preferentially prevent the exchange of protein-bound GDP and in some cases were shown to inhibit GAP-induced GTP hydrolysis. RanBP1 is the first member of a new class of proteins regulating the binding and hydrolysis of GTP by Ras-related proteins.

Ubiquitin is attached to membranes of baculovirus particles by a novel type of phospholipid anchor

Purified budded virions of Autographa californica nuclear polyhedrosis virus (AcNPV) contain abundant amounts of free ubiquitin, which has an altered electrophoretic mobility on SDS gels as compared with standard ubiquitin. Phase extraction of virion proteins with Triton X-114 indicated that the modified form of ubiquitin behaved as an integral membrane protein. The membrane-bound form of ubiquitin was labeled with both phosphate and palmitate, and its electrophoretic mobility was altered by treatment with phospholipase A2 and a phosphatidylcholine-specific phospholipase D. Mild trypsin digestion indicated that the acyl group was not linked to the C-terminus of the protein. Acylated ubiquitin could not be radiolabeled with a membrane-impermeable Bolton-Hunter reagent unless virus was pretreated with detergent. Together, these experiments suggest that ubiquitin is attached to the inner face of the viral membrane by a novel type of phospholipid anchor.

Elevated gene expression and production of interleukins 2, 4, 5, and 6 during exposure to vomitoxin (deoxynivalenol) and cycloheximide in the EL-4 thymoma

Aberrant elevation of serum IgA and induction of murine IgA nephropathy following dietary exposure to the naturally occurring trichothecene vomitoxin (VT or deoxynivalenol) may involve dysregulation of cytokine production at the T cell level. EL4.IL-2 (EL-4), a cloned thymoma that produces interleukins (IL)-2, 4, 5, and 6, was used as a T cell model to investigate the in vitro effects of VT on interleukin production and gene expression. When supernatants of cells stimulated with phorbol 12-myristate 13-acetate (PMA) were assessed by enzyme-linked immunosorbent assay, IL-2, 4, and 5 were increased in the presence of 50 and/or 100 ng/ml VT for 2 and/or 8 days of culture. IL-2, 5, and 6 were also significantly elevated in the presence of 10-100 ng/ml of cycloheximide (CHX), another protein synthesis inhibitor, after 8 days of culture. As demonstrated by Northern analysis, VT at the levels between 50 and 100 ng/ml superinduced IL-2, 4, 5, and 6 mRNAs in PMA-stimulated EL-4 cells during a 24 hr culture period. Similar effects in PMA-treated samples were observed for CHX at 50, 100, 250, 1000, and 10000 ng/ml. mRNA levels for both IL-4 and IL-5, but not IL-2 and IL-6, were increased in unstimulated EL-4 cultures exposed to 50 and 100 ng/ml VT for 48 hr when analyzed by reverse transcriptase-polymerase chain reaction. Using [3H]leucine incorporation as a measurement of protein synthesis, IC50s for VT and CHX were estimated to be 280 and 55 ng/ml, respectively. This study indicates that VT as well as CHX could increase production of several interleukins in the EL-4 model even when present at concentrations that partially inhibited protein synthesis, whereas IL mRNA superinduction occurred across a broader range of concentrations that included maximal protein synthesis inhibition.

Effects of inhibitor of endothelium-derived relaxing factor on hypoxic contraction of isolated pig coronary artery

Exposure of isolated pig coronary artery with endothelium intact to hypoxia Krebs-Henseleit solution aerated with 95% N2 + 5% CO2 caused a transient contractile response, and the coronary artery without endothelium exhibited a gradual decrease in basal tension. The endothelium-dependent contractile response to hypoxia was almost completely blocked by nitro-L-arginine (0.2 mmol.L-1), and inhibited by methylthioninium chloride (10 mumol.L-1). The inhibitory effect of the NLA was partially reversed by L-arginine (2 mmol.L-1). Sodium nitroprusside (10 mumol.L-1) was also completely antagonized and nicorandil (0.3 mol.L-1) remarkably reduced the hypoxic contractile response. Tetraethylammonium (10 mmol.L-1) and glibenclamide (1 mumol.L-1) had little effect on hypoxia-induced vascular contraction, whereas cromakalim (1 mumol.L-1) produced obvious relaxing effect on hypoxic response. These results suggest that suppression of basally released nitric oxide (NO) is an important mechanism of coronary vasoconstriction induced by hypoxia.

Functional dissection of the Autographa california nuclear polyhedrosis virus enhancer element hr5

The hr5 enhancer element of Autographa californica nuclear polyhedrosis virus stimulates transcription from baculovirus-delayed early promoters in the presence of the viral transactivator, IE1. Gel retardation analyses of interactions between a fragment of hr5 and extracts prepared from cells transfected with an IE1-encoding plasmid revealed the presence of three DNA-protein complexes. In order to better define the functional domains of the hr5 enhancer, we constructed a set of plasmids containing partial deletions in the enhancer element. These constructs were tested for both in vitro DNA binding activity and enhancer function in transient assays. The results indicated that the minimum sequence required for DNA-protein interactions was half of the conserved 24-bp palindrome that is contained within a 60-bp direct repeat (DR60). However, the minimum sequence required for enhancer function was a complete copy of DR60. Template challenge experiments indicated that IE1 bound with equal affinity with a complete or a half copy of DR60. The deletion analyses were confirmed by in vitro binding and transient expression assays with synthetic oligonucleotides.

Progressive serum IgE elevation in the B6C3F1 mouse following withdrawal of dietary vomitoxin (deoxynivalenol)

Vomitoxin (deoxynivalenol) is a fungal toxin that induces serum IgA hyperelevation, IgA autoantibodies, mesangial IgA deposition in mice upon dietary exposure. The capacity of dietary vomitoxin to similarly alter serum IgE was assessed in female B6C3F1 mice. Ingestion of 25 ppm vomitoxin in AIN-76A semipurified diet resulted in 2.7-, 4-, 5- and 2.3-fold increases in serum IgE relative to controls after 12, 16, 20, and 24 weeks of toxin feeding, respectively. When mice were fed 25 ppm vomitoxin for 8 weeks and continued on toxin-free diet, serum IgE levels were 2.4, 4, 4.9, and 2-fold that of controls at 12, 16, 20, and 24 weeks, respectively. IgE levels were not significantly different between treatment and withdrawal groups at Weeks 12-24. These results differed from those of serum IgA, which increased much earlier and only during toxin administration, and those of IgG, which was largely unaffected compared to controls. The results indicate that a defined period of vomitoxin ingestion can subsequently induce progressive dysregulation of IgE production in addition to previously described IgA-related pathologic effects.

Capsid assembly and involved function analysis of twelve core protein mutants of duck hepatitis B virus

The roles of different regions of the duck hepatitis B virus (DHBV) core protein on viral capsid assembly and related functions were examined. Twelve deletion and insertion mutations which covered 80% of the DHBV C open reading frame were constructed and expressed in Escherichia coli. The N-terminal region (amino acids 3 to 66) of DHBV core protein was important for its tertiary structure and function in E. coli. The expressed core mutants without this region apparently inhibited E. coli growth. The results of transmission electron microscopy of E. coli thin sections, capsid agarose gel, and sucrose gradient sedimentation demonstrated that a few DHBV core mutants with insertion in the N terminus and deletion in the C terminus retained the ability to form core-like particles in E. coli. However, other mutations in most of N-terminal and central regions strongly inhibited the self-assembly ability of DHBV core protein in E. coli. In addition, the mutant with a C-terminal region deletion (amino acids 181 to 228) lost most of the nucleic acid-binding activity of the DHBV core protein.

Transcriptional interactions of transforming growth-factor-β with pro-inflammatory cytokines

BACKGROUND

Inflammation and tissue injury are characterized by a massive infiltration of mononuclear cells. These pro-inflammatory cells, which are the precursors of an inflammatory response by the immune system, secrete a variety of cytokines and growth factors that alter the biosynthetic repertoire of the resident connective tissue cells. Specifically, expression of connective tissue matrix metalloproteinases, such as stromelysin and interstitial collagenase, is enhanced, together with the expression of chemoattractants for leukocytes, such as interleukin-8 (IL-8). These events lead to increased connective tissue degradation. We have examined the growth factor regulation of expression in cultured fibroblasts of the prototypic pro-inflammatory factors interstitial collagenase and IL-8.

RESULTS

We demonstrate that transforming growth factor-beta (TGF-beta) does not interfere with cytokine-induced IL-8 gene expression, nor does it affect the activity of NF-kappaB-driven promoters. In contrast, TGF-beta down-regulates collagenase gene expression through the induction of the jun-B proto-oncogene. Jun-B is a negative regulator of c-jun, which mediates cytokine activation of collagenase gene expression through its action as a component of the AP-1 transcription factor.

CONCLUSION

Our data suggest that TGF-beta may attenuate the deleterious events that occur in inflammation by preventing cytokine-induced extracellular matrix degradation, although it does not affect cytokine-induced recruitment of pro-inflammatory cells. Furthermore, our data suggest a potential therapeutic use for jun-B, which may be a candidate for gene therapy in disease states that are characterized by excessive connective tissue degradation.

Study on cytomegaloviral infection in acute leukemia patients by polymerase chain reaction

Polymerase chain reaction (PCR) and blot hybridization by probe labelled with digoxin were used to detect human cytomegalovirus (HCMV) DNA in 31 patients with acute leukemia and 20 controls. The positive rate detected by PCR in acute leukemia was 74.2% and 15.0% in the controls. The difference was statistically significant. The results suggest that acute leukemia patients are the high risk population with high infection rate of HCMV. The positive rate detected by digoxin method in acute leukemia was 58.1%. Six patients showed negative results by digoxin method, but positive by PCR. It was demonstrated that PCR was superior to digoxin method in sensitivity. Anti-HCMV IgM in serum of patients was detected at the same time, the positive rate was 16.1%. Only 6 of the 23 PCR positive patients showed positive anti-HCMV IgM. It suggests that the immune response is weak in acute leukemia patients and HCMV recently infected could not be excluded in the anti-HCMV IgM negative cases.

Detection of HCV infection by cPCR in patients with acute leukemia

HCV RNA and anti-HCV were detected respectively by complemented DNA polymerases chain reaction (cPCR) and ELISA in the sera of 28 acute leukemia patients with repeated blood transfusion and changes in liver function. HCV RNA positive rate was 78.6%. Anti-HCV positive rate was 60.7%. 25 subjects showed positive results in HCV RNA or anti-HCV, or in both of them. By combined assessment, the HCV infection rate was 89.3%. Acute leukemia patients were the high risk group of HCV infection because of the lowered immune function and repeated blood transfusion. By cPCR, HCV RNA can be detected earlier and the sensitivity is higher than by anti-HCV. So cPCR is a sensitive and specific method for early diagnosis of HCV infection. The combination of HCV RNA and anti-HCV detection methods may improve the diagnostic rate of HCV infection.

[Alternative combination chemotherapy with mitomycin C, vincristine, methotrexate, 5-fluorouracil, cis-platinum and adriamycin for adenocarcinoma of the lung]

Efficacy of an alternative combination chemotherapy with MMC, VCR, MTX, 5-FU, CDDP and ADM for adenocarcinoma of the lung is reported. Forty-one advanced cases (stage III: 9; IV: 32) were chosen for the chemotherapy. Two combination chemotherapies MMC + VCR + MTX + 5-FU + CDDP: MVMFP; MMC + VCR + MTX + 5-FU + ADM: MVMFA were repeated alternatively for 8 consecutive weeks with 2 interposed rest weeks, and this regimen was completed in 34 cases. All 41 cases were evaluable. Three and 26 cases achieved complete and partial responses, respectively. The response rate was 70.7%, and the median survival time was 13 months. The adverse effects of the chemotherapy observed were tolerable: alopecia (63.4%), gastrointestinal symptoms (14.5%), bone marrow toxicity (12.2%) and liver dysfunction (4.8%). These results indicate that our MVMFP/MVMFA alternative chemotherapy is quite effective for adenocarcinoma of the lung, comparable or superior to conventional chemotherapies.

In vitro vomitoxin exposure alters IgA and IgM secretion by CH12LX B cells. Relationship to proliferation and macromolecular synthesis

The CH12LX cell line was used as a clonal model to assess the direct effects of vomitoxin on IgM and IgA secretion in B cells. When vomitoxin was included in LPS-driven CH12LX B cell cultures, it had multiple effects on Ig secretion. Whereas vomitoxin doses of 115 and 120 ng/ml caused 50% inhibition (ID50) of IgA and IgM production, respectively, toxin concentrations in the 5 to 50 ng/ml range slightly stimulated IgA production. However, low vomitoxin doses did not induce switching of membrane IgM+ CH12LX B cells to membrane IgA+. Total cell number was unaffected at vomitoxin concentrations up to 100 ng/ml but dropped markedly at 200 ng/ml (ID50 = 170 ng/ml). Using the MTT reduction assay as another measure of viability and cell function, vomitoxin was also inhibitory (ID50 = 130 ng/ml). Both thymidine incorporation and leucine incorporation were also inhibited by the toxin with estimated ID50s being 120 and 110 ng/ml, respectively. The results indicate that although at high doses, vomitoxin inhibits proliferation, Ig secretion and DNA/protein synthesis in the clonal B cell model, the toxin marginally stimulated IgA secretion at lower doses.

Identification of a leucine-to-proline mutation in the keratin 5 gene in a family with the generalized Köbner type of epidermolysis bullosa simplex

We have previously reported linkage of a large Finnish family with the generalized (Köbner) type of epidermolysis bullosa simplex to chromosome 12q in the region containing the type II keratin gene cluster (Ryynänen et al., Am J Human Genet 49:978-984, 1991). In this study, we examined the possibility that keratin 5, the type II keratin expressed in the basal keratinocytes, harbors the mutation in this family. Nucleotide sequencing revealed a T-to-C transition within exon 7 of the keratin 5 gene in the affected individuals of the family, while the unaffected individuals showed no evidence of C. The presence of the T-to-C transition in the affected individuals was confirmed by restriction enzyme digestion analysis with NciI endonuclease, as well as with PCR amplification of specific alleles (PASA) analysis. The PASA analysis also indicated that the mutated allele was not found among the 100 alleles tested within the general Finnish population indicating that the mutated allele is not a common polymorphism. Furthermore, the mutated allele was not present in nine individuals representing three different EBS families of Finnish origin. The T-to-C transition at the nucleotide level resulted in substitution of a leucine by a proline at the amino acid level, and the substitution affected a leucine residue which was invariant among eight different human keratins in a highly conserved segment at the carboxy-terminal region of the keratin 5 polypeptide.(ABSTRACT TRUNCATED AT 250 WORDS)

Persistent dysregulation of IgA production and IgA nephropathy in the B6C3F1 mouse following withdrawal of dietary vomitoxin (deoxynivalenol)

To assess whether vomitoxin-induced dysregulation of IgA production and IgA nephropathy are reversible, relevant immunologic parameters were compared among experimental groups of B6C3F1 mice that were fed: (1) 25 ppm vomitoxin in AIN-76A semipurified diet for 24 weeks (treatment group), (2) 25 ppm vomitoxin for 8 weeks and then control diet for 16 weeks (withdrawal group), and (3) control diet for 24 weeks (control group). Levels of serum IgA and microhematuria index in the treatment group were elevated after 4 to 8 weeks and continued to increase with further vomitoxin exposure. IgA immune complexes and mesangial IgA deposition, as quantitated by interactive laser cytometer image analysis, were also increased with toxin exposure at Weeks 8, 16, and 24, whereas IgM, IgG, and complement component C3 deposition were unaffected or depressed. Serum IgA, microhematuria index, and mesangial IgA deposition in withdrawal mice remained elevated over those of the controls at Weeks 16 and 24 but were less than those of the treatment group. Cell recovery from Peyer's patches (PP) as well as the percentages of IgA+ and CD4+ cells in PP and spleen at Weeks 16 and 24 were greater in treatment mice than in controls, but only the percentage of IgA+ cells in PP was elevated in the withdrawal mice at these the same time points. When IgA secretion by unstimulated and LPS-stimulated splenic lymphocytes was used as the measure of systemic production, it was elevated in both treatment and withdrawal mice at Weeks 16 and 24. The results indicated that experimental dysregulation of IgA production and IgA nephropathy persisted up to 4 months after a discrete period of dietary vomitoxin exposure, but that the severity of these effects did not increase in a progressive fashion.

Baculovirus phosphoprotein pp31 is associated with virogenic stroma

The PstI K fragment of Autographa californica nuclear polyhedrosis virus (AcMNPV) encodes a protein with a molecular weight of 31,000. To define the role of this protein (pp31) in virus infection further, it was overexpressed in bacteria and used to produce polyclonal antiserum. Radioimmunoprecipitation analysis indicated that pp31 was synthesized during both the early and late phases of virus infection, consistent with previous analyses indicating that the gene was regulated by tandem early and late promoters. Metabolic labeling of cells with carrier-free phosphate indicated that pp31 was phosphorylated. Biochemical fractionation experiments showed that pp31 was localized in the nucleus and that it was more stably associated with the nucleus at later times of infection. Immunoblot analysis of subnuclear fractions indicated that pp31 was associated predominantly with the chromatin and nuclear matrix fractions. Immunofluorescence experiments confirmed that the pp31 protein was localized in the nucleus. Nuclear staining was relatively uniform early but was more centrally nuclear later in infection. Immunoelectron microscopy indicated that the pp31 protein was a component of virogenic stroma. Southwestern (DNA-protein) blot analysis demonstrated that pp31 is a DNA-binding protein. These findings suggest a possible role for pp31 in the virus life cycle.

[Protective action of phenytoin on cerebral ischemia in rats]

In order to study and modify the ischemic brain lesions, protecting the reversible damage of neurons, and limiting the ischemic damage both models of cerebral ischemia--focal cerebral ischemia induced by photochemically, and brain reperfusion after ligation of common carotid arteries bilateral in Wistar rats were used to investigate the protective effect of diphenylhydantoin (DPH) on cerebral ischemia. Two groups of rats received DPH 10 mg/kg and 30 mg/kg respectively were compared with those having received normal saline immediately after cerebral ischemia. The effects of DPH on the changes of EEG, biochemical marker and pathologic lesion in focal cerebral ischemia in rats were evaluated. The results showed that the degree of restoration of EEG in the group treated with DPH was better than in the group with normal saline, the content of water in ischemic cerebral tissue was decreased significantly (P < 0.05), the activity of Na-K-ATPase and antioxidant was increased significantly (P < 0.01, P < 0.05, respectively), and the percentage of necrotic neurons in periischemic area was decreased markedly (P < 0.001) in groups treated by DPH. The results suggest that there is a definite protective effect of DPH on cerebral ischemia.

Effects of various noise exposures on endocochlear potentials correlated with cochlear gross responses

Changes in endocochlear potentials (EP), cochlear microphonics (CM), and compound action potentials (CAP) with noise exposure were investigated in guinea pigs. The animals were anesthetized and immobilized and exposed to white noise at intensities ranging from 105 to 125 dB. The negative EP (N-EP) was induced by anoxia and was investigated during and after noise exposure. It was found that the general EP (G-EP, the sum of both positive EP (P-EP) and N-EP) increased remarkably during exposure to 115 dB noise but decreased during exposure to 125 dB noise. A smaller absolute value of N-EP was encountered only during exposure to 125 dB noise. The results shed light on the relationship between EP and CM, CAP changes, and the potential mechanism of EP change and its significance in noise-induced hearing loss.

[Relation between malondialdehyde generation by platelets and plasma thromboxane B2 and diagnostic classification by syndrome differentiation of traditional Chinese medicine in stroke during acute stage]

The malondialdehyde generation by platelets and TXB2 in poor platelet plasma were examined in 36 patients with stroke during acute stage. By CT examination 19 cases were diagnosed hemorrhagic, 17 cases ischemic; while by syndrome differentiation of TCM 16 cases belonged to Zhongzangfu(middle internal organs), 20 cases Zhongjingluo (middle channels). Results showed that the malondialdehyde generation by platelets was reduced, TXB2 in poor platelet plasma increased in patients, compared with those in the healthy controls. This finding was common in stroke during acute stage and was not related to diagnostic classes by either CT examination or syndrome differentiation of TCM. This study indicates that maintenance of normal platelet function may have significant implication in the prevention and treatment of cerebrovascular disease.