Generation of 28 sequence-tagged sites (STSs) from yeast artificial chromosome (YAC) clones anchored at human chromosome 21q22.1 region

Twenty-eight sequence-tagged sites (STSs) were newly generated from the DNA sequences of vector-insert junctions from yeast artificial chromosomes (YACs) anchored at chromosome 21q22.1 region. The insert DNAs adjacent to vector arms were specifically amplified through inverse PCR method to clone into pUC19 vector for sequencing. Sixty DNA junctions from 44 CEPH YAC clones were cloned and sequenced. Of these DNA sequences of junctions between vector-arms and DNA inserts, twenty-eight STSs were finally obtained to show the accurate amplification, which is specific for human chromosome 21. The sets of 28 STSs were useful to build fine YAC contigs by STS-mediated YAC walking at the 21q22.1 region.

Renal lesion of type Ia glycogen storage disease: the glomerular size and renal localization of apolipoprotein

In order to investigate the glomerular size and renal localization of apolipoprotein in type Ia glycogen storage disease, a renal biopsy was performed in two proteinuric patients. Histopathological examination of the biopsy specimens revealed focal sclerotic glomerular sclerosis in both patients. The mean glomerular area was 21.6 +/- 11.6 x 10(3) microns 2, indicating enlargement of the glomeruli. Immunohistochemical staining of the specimens for apolipoprotein showed localization of apolipoprotein AI on the inner side of the glomerular capillary wall, and in proximal tubular epithelial cells. In one patient with a history of several episodes of hypoglycemia, treatment with corn starch improved the carbohydrate and lipid metabolic profile and reduced the daily urinary protein excretion from 2.23 to 0.5 g. These results suggest that focal sclerotic glomerular lesions associated with type Ia glycogen storage disease may be related to disorders of carbohydrate and lipid metabolism.

Effects of mood states, smoking and urinary catecholamine excretion on hemoglobin A1c in male Japanese workers

To know the association between psychological strain and glycosylated hemoglobin (HbA1c) and to examine roles of smoking and catecholamine excretion as a possible mediator in the association, we measured mood states (Profile of Mood States, POMS), urinary catecholamines (adrenalin, noradrenaline and dopamine) from urine sample in early morning, HbA1c and fasting plasma glucose (FPG) of 63 male employees on a rest day. After excluding 12 subjects who had diabetes or impaired glucose tolerance or had missing response to the questionnaire, data from 51 subjects were analyzed. The POMS anger-hostility score significantly and positively correlated with HbA1c (p < 0.05), while other scale scores did not (p > 0.05). Number of cigarettes smoked per day significantly and positively correlated with HbA1c (p < 0.05). Urinary excretion rate of any catecholamine did not significantly correlate with HbA1c (p > 0.05). Multiple linear regression analysis indicated that the anger-hostility score significantly correlated with HbA1c after controlling for number of cigarettes per day (p < 0.05). It is suggested that, among mood states, anger-hostility is associated with increased HbA1c. However, our study failed to find a mediating role of urinary catecholamines or smoking on the association between the mood and HbA1c.

Bone-resorbing activities of 24-epi-1 alpha-hydroxyvitamin D2 and 24-epi-1 alpha,25-dihydroxyvitamin D2

Bone-resorbing activities of 24-epi-1 alpha-hydroxyvitamin D2 [24-epi-1 alpha(OH)D2], 24-epi-1 alpha,25-dihydroxyvitamin D2 [24-epi-1,25(OH)2D2], and 1 alpha,24S,25-trihydroxyvitamin D2 [1,24S,25(OH)3D2], which might be a metabolite of 24-epi-1,25(OH)2D2, were investigated. In an in vitro bone resorption test, the activity of 24-epi-1 alpha(OH)D2 was similar to that of 1 alpha-hydroxyvitamin D3 [1 alpha(OH)D3] at 10(-9) M-10(-6) M. The activity of 24-epi-1,25(OH)2D2 was weaker than that of 1 alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3] at 10(-11) M-10(-8) M. On the other hand, the activity of 1,24S,25(OH)3D2 was similar to that of 24-epi-1,25(OH)2D2 at 10(-11) M-10(-9) M. In the formation assay of osteoclast-like cells, the activity of 24-epi-1 alpha(OH)D2 was weaker than that of 1 alpha(OH)D3 at 10(-7) M. The activity of 24-epi-1,25(OH)2D2 was almost similar to that of 1,25(OH)2D3 at 10(-11) M-10(-7) M. The activity of 1,24S,25(OH)3D2 was significantly weaker than that of 24-epi-1,25(OH)2D2 at 10(-11) M-10(-9) M. In the two experiments, the potencies of 24-epi-1,25(OH)2D2 were about 100 times higher than those of 24-epi-1 alpha(OH)D2. In an in vivo/in vitro bone resorption test, the activity of 24-epi-1 alpha(OH)D2 was almost similar to those of 1 alpha(OH)D3 and 1,25(OH)2D3 and higher than those of 24-epi-1,25(OH)2D2 and 1,24S,25(OH)3D2. 24-epi-1 alpha-(OH)D2 and 1 alpha(OH)D3 were longer lasting than 24-epi-1,25(OH)2D2 and 1,25(OH)2D3 in this experiment.(ABSTRACT TRUNCATED AT 250 WORDS)

Purification and analysis of a flavoprotein functional as NADH oxidase from Amphibacillus xylanus overexpressed in Escherichia coli

The gene encoding the Amphibacillus xylanus flavoprotein has been cloned into pTTQ18 and overexpressed in Escherichia coli. The recombinant enzyme has been purified to homogeneity yielding 15 mg of pure enzyme/liter of cell culture. Recombinant flavoprotein is fully active and has an absorption spectrum identical to that of the enzyme purified from A. xylanus. The N-terminal sequence analysis and analytical gel filtration data confirm the structural identity of recombinant and A. xylanus enzymes. The Km value for oxygen and the Km value for NADH are 1.7 mM and 33.3 microM, respectively. In the presence of free additional FAD, however, the Km value for oxygen decrease dramatically. The NADH oxidase activity is accelerated markedly in the presence of additional FAD. The intracellular free FAD concentration of A. xylanus is calculated about 13 microM. This FAD concentration would be enough to accelerate the NADH oxidase activity of flavoprotein in cells of A. xylanus. Two-electron reduction of the enzyme FAD by the strong reductant dithionite occurs during the total uptake of 6 electrons. Such behavior usually indicates the presence of non-flavin redox centers. The high degree of homology between this enzyme and alkyl hydroperoxide reductase F52a protein and thioredoxin reductase suggests that these centers are the redox-active disulfide adjacent to the FAD and another disulfide, which is able to slowly interchange with the redox-active disulfide. The presence of two disulfides has been demonstrated.

Genomic structure and chromosomal localization of processed pseudogenes for human RBP-Jk

The functional gene for human recombination signal sequence-binding protein (RBP-Jk) and corresponding processed psudogenes have been isolated from various species, such as Drosophila, Xenopus, mouse, and human. Here we report the isolation of another two genomic pseudogenes of human RBP-Jk, named K2 and K7, from a cosmid library of Hela cells. The nucleotide sequences of both genes exhibited more than 95% homology to the functional human gene for RBP-Jk. Moreover, they did not contain any intron sequences and were interrupted by several stop codons in all frames. In situ hybridization demonstrated that the pseudogenes, K2 and K7, were localized at chromosomes 9p13 and 9q13, respectively. Their physical maps differed from those of the true functional gene and of the pseudogenes reported previously by Amakawa et al. (1993).

Microphthalmia-associated transcription factor as a regulator for melanocyte-specific transcription of the human tyrosinase gene

Tyrosinase is a rate-limiting enzyme in melanin biosynthesis and is specifically expressed in differentiated melanocytes. We have identified the enhancer element in the 5'-flanking region of the human tyrosinase gene that is responsible for its pigment cell-specific transcription and have termed it tyrosinase distal element (TDE) (positions -1861 to -1842). Transient expression assays showed that TDE confers efficient expression of a firefly luciferase reporter gene linked to the tyrosinase gene promoter in MeWo pigmented melanoma cells but not in HeLa cells, which do not express tyrosinase. TDE was specifically bound by nuclear proteins of MeWo and HeLa cells, the binding properties of which were indistinguishable in gel mobility shift assays. TDE contains the CATGTG motif in its center, and mutation analysis indicates that the CA dinucleotides of this motif are crucial for protein binding and pigment cell-specific enhancer function. The CATGTG motif is consistent with the consensus sequence recognized by a large family of transcription factors with a basic helix-loop-helix structure, which prompted us to examine the possible involvement of a ubiquitous transcription factor, USF, and a novel factor, microphthalmia-associated transcription factor (MITF), recently cloned as the human homolog of the mouse microphthalmia (mi) gene product. The mi phenotype is associated with a mutant mi locus and characterized by small eyes and loss of melanin pigments. Both USF and MITF are predicted to contain a basic helix-loop-helix structure and a leucine zipper structure. We provide evidence that USF binds to TDE, whereas we were unable to detect the DNA-binding activity of MITF. Transient coexpression assays showed that MITF specifically transactivates the promoter activity of the tyrosinase gene through the CATGTG motif of TDE but not the promoter of the ubiquitously expressed heme oxygenase gene, while USF is able to activate both promoters. These results indicate that MITF is a cell-type-specific factor that is capable of activating transcription of the tyrosinase gene.

Regulation of c-jun by lung carcinogens in Clara cells of hamsters

In vitro differentiated hamster Clara cells were used to study the effects of lung carcinogens on the regulation of the c-jun oncogene. Northern blot analysis revealed a decrease in the expression of jun transcripts 24 h following the exposure of Clara cells to the direct acting forms of benzo[a]pyrene (BPDE*) or 5-methylchrysene (5MeCDE). To determine whether this decrease was mediated at the transcriptional level, we have used CAT reporter constructs driven by nested deletions of the 5' non-coding regulatory region of the c-jun oncogene. While BPDE was capable of activating certain regulatory domains of the c-jun promoter, this activation was not observed with either 5MeCDE or the less active lung carcinogens BADE or 6MeCDE. Analysis of enhancer elements identified the SP1 target site as a strong silencer after BPDE treatment. While positive regulatory element(s) mediating activation of c-jun by BPDE were localized within the promoter region up to -1639, further upstream sequences reduced this transcriptional activation. Thus, when the complete promoter region, up to -4500, was tested, no transcriptional activation was noted following BPDE treatment. These observations suggest that the regulation of c-jun in Clara cells exposed to potent lung carcinogens is mediated at the post-transcriptional level, possibly by reducing the stability and, in turn, the half life of c-jun mRNA. Overall, in contrast to the response of c-jun to numerous carcinogens and stress inducing agents noted in various other cell systems, our findings suggest the existence of a tissue-specific regulatory response for c-jun.

[Protective effect and antibody titer of intravenous immunoglobulin (IVIG) against clinical isolates of opportunistic bacteria]

Neonates and leukopenic, immunosuppressed patients are at high risk for severe infection of opportunistic pathogens despite of the availability of potent antimicrobial agents. In this study, antibody titers of immunoglobulin preparations (IVIG) were contrasted with the protective effect in mice against each of bacterial infection. Antibody titers were determined by ELISA. The antigens were 70-80 clinical isolates of Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus, respectively. Antibody titers of IVIG against these three gram-negative bacteria ranged 3200 to 102,400. ICR mice were inoculated intraperitoneally with each of several strains against which IVIG showed various titers. IVIG showed rather high protective activities against well-reactive strains, while it showed little protective activities against poor-reactive strains. In the case of P. aeruginosa, statistical analysis of the results obtained with the antibody titer and efficacy showed a good correlation (p < 0.01). On the other hand, IVIG showed a high and complicate antibody titer against S. aureus IVIG ranging 400,000 to 12,800,000, since apparent titers contained non-specific binding of Fc portion of IgG with protein A on the cell wall. IVIG was active in mice, where protein A was less and specific binding was stronger. Bacterial cells have various components; lipopolysaccharide, lipid A, capsule, flagella, pill, etc. that are responsive to specific antibodies. This study indicates that IVIG have such antibodies and that is associated with protective activity against bacterial infection in proportion to antibody titer.

DNA fingerprinting involving fluorescence-labeled termini of any enzymatically generated fragments of DNA

We have developed a new fluorescence-based method for DNA fingerprinting that does not require a fluorescent linker or a synthetic oligonucleotide primer, both of which are normally used for labeling of DNA. Cosmid DNAs are digested with appropriate restriction enzymes and the 3' termini of DNA fragments are labeled with the corresponding, fluorescent dye-conjugated dideoxynucleotide triphosphate terminator (dye-ddNTP) by the Klenow fragment of DNA polymerase I from Escherichia coli, which has 3'-->5' exonuclease and replacement activities as well as its main 5'-->3' polymerase activity. Samples are separated on a DNA-sequencing gel and data are analyzed by application of both the Version 0.3.8a mapper program (Applied Biosystem Inc., Foster City, CA) and our Overlap I program that facilitate rapid analysis of the frequency of overlapping of cosmid DNAs. Using this method we have determined the overlap frequency of DNA fragments of each cosmid clone from the mouse MHC class I gene cluster.

The significance of right ventricular ischemia in reflex bradycardia in humans

Heart rates (HR) were measured before (control HR) and after (ischemic HR) balloon inflation during percutaneous transluminal coronary angioplasty in 96 patients with effort angina pectoris. The delta HR, defined as (ischemic HR-control HR), in the right coronary artery occlusion was significantly smaller than that in the left anterior descending artery or left circumflex artery occlusion. Among right coronary artery occlusions the delta HR in segment 1 occlusion was significantly smaller than that in segment 2 or segment 3 occlusion. It is suggested that the ischemia of the right ventricle plays an important role in producing a reflex bradycardic response in humans.

Response to osmotic stimuli in mesangial cells: role of system A transporter

It has been suggested that mesangial cells have an osmoregulatory mechanism like that of renal medullary cells, such as intracellular accumulation of polyols in response to hypertonicity. We examined osmoregulatory role of neutral amino acids transported by system A in cultured mesangial cells. The contents of almost all amino acids increased under hypertonic conditions to more than twice the value in isotonic cells. In hypertonic cells, the system A transport activity, measured by Na(+)-dependent 2-(methylamino)isobutyric acid (MeAIB) uptake, was 3.8-fold the uptake in isotonic cells, reaching a maximum 16 h after the switch to hypertonic medium. The response to hypertonicity was the result of an increase in maximal velocity without change in Michaelis constant and was dependent on RNA and protein synthesis. When medium osmolality decreased from hypertonic to isotonic, MeAIB uptake reverted to the isotonic level within 16 h and a large transient efflux of L-proline occurred within 10 min. These results suggest that mesangial cells respond to extracellular hypertonicity by increasing system A transport activity and neutral amino acids can function as compatible osmolytes in mesangial cells.

[The pathogenic mechanism of experimental autoimmune encephalomyelitis and approach for new immunological therapy]

Experimental autoimmune encephalomyelitis (EAE) is an autoimmune disease mediated by myelin protein-specific CD4 T cells of the Th 1 phenotype and is a major animal model for the study of multiple sclerosis. Here we review current research advancements on the pathogenic mechanism of disease induction, remission and exacervasion. Progresses both in the molecular biology and immunology permit us to make a new strategy of specific therapy for EAE. There are three important strategies to prevent disease; the first is to block the trimolecular complex and associated accessory molecules to stop the T cell activation, the second is to regulate the activated T cells with immunological networking system and the third is to modulate the immunological responses mediated by T cells in the central nervous system.

A novel pathway for retinoic acid-induced differentiation of F9 cells that is distinct from receptor-mediated trans-activation

Retinoic acid (RA) has striking effects on vertebrate development and induces differentiation of several lines of cells including embryonal carcinoma F9 cells. It is generally accepted that the actions of RA are mediated by nuclear receptors for RA. However, we now provide evidence that F9 cells can differentiate in response to RA without trans-activation by nuclear receptors. Irreversible differentiation of F9 cells was induced by 18 h of exposure to RA with subsequent incubation in the absence of RA. This induction of differentiation was not blocked after inhibition of protein synthesis and mRNA synthesis during the 18-h treatment with RA, but the endogenous RA receptors failed to activate transcription from their target genes that contain the receptor-binding sequences. During the commitment to RA-induced differentiation, at least five sets of four phosphorylated proteins underwent changes in the absence of protein synthesis de novo. These results suggest that there is a novel pathway for the action of RA that is independent of nuclear receptor-mediated trans-activation.

Cloning of the human DOPAchrome tautomerase/tyrosinase-related protein 2 gene and identification of two regulatory regions required for its pigment cell-specific expression

We have cloned and sequenced the human genomic DNA segments encoding the 5'-flanking region and the first two exons of the DOPAchrome tautomerase (DT)/tyrosinase-related protein 2 (TRP-2) gene. The DT gene is a member of the tyrosinase gene family and specifically expressed in melanin-producing cells. A transcriptional initiation site of the DT gene was identified by S1 nuclease-mapping and primer-extension analyses using RNA prepared from human pigmented melanoma cells. To study the mechanism for pigment cell-specific expression of the human DT gene, we analyzed the promoter function of its 5'-flanking region by transient expression assays. The fusion genes, containing the DT gene promoter upstream from a firefly luciferase reporter gene, were introduced into human pigmented melanoma cells and HeLa cells, and the pigment cell-specific promoter activity was evaluated by comparing the luciferase activity expressed in both cell lines. A series of 5' deletion studies of the human DT gene promoter revealed that the 32-bp element, located between -447 and -415, is sufficient to confer pigment cell-specific expression of a reporter gene on a homologous promoter, but not on a heterologous simian virus 40 promoter. Internal deletion studies using a homologous or a heterologous promoter revealed that the pigment cell-specific expression of a reporter gene mediated by the 32-bp element is dependent on the presence of another region of the DT gene spanning from -268 to -56, which was termed the proximal region. However, the proximal region by itself is not sufficient to confer cell type-specific expression. These results indicate that the presence of two regulatory regions, the 32-bp element and the proximal region, is required for pigment cell-specific expression of the DT gene. Both regulatory regions contain a CANNTG motif, a well known binding site for a large family of transcription factors possessing a basic helix-loop-helix structure.

Effects of TNF-alpha on hemodynamic changes and circulating endothelium-derived vasoactive factors in dogs

To elucidate the relation of tumor necrosis factor-alpha (TNF-alpha)-induced hemodynamic change to endothelium-derived vasoactive factors, we simultaneously measured hemodynamic parameters and circulating endothelin (ET)-1, ET-3, nitrite/nitrate (NOx), and 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) in anesthetized dogs following administration of TNF-alpha with or without NG-nitro-L-arginine (L-NNA), a nitric oxide (NO) synthase inhibitor, and indomethacin, a cyclooxygenase inhibitor. Natural human TNF-alpha (10 micrograms/kg, n = 5) with or without L-NNA (1 mg/kg, n = 5) or indomethacin (2 mg/kg, n = 5) was administered intravenously as a bolus, while administration of vehicle served as control (n = 5). After administration of TNF-alpha, mean arterial pressure and cardiac index significantly decreased, whereas systemic (SVRI) and pulmonary (PVRI) vascular resistance index increased. Plasma levels of ET-1, ET-3, NOx, and 6-keto-PGF1 alpha significantly (P < 0.01) increased at 1 h. L-NNA or indomethacin blocked TNF-alpha-induced hypotension and remarkably increased SVRI but did not affect decreased cardiac index. Our data suggest that endogenous ET-1 may partly contribute to TNF-alpha-induced increases in SVRI and PVRI, against which ET-3, NO, and prostacyclin may function as compensatory vasodilators.

[Effect of gamma-immunoglobulin in experimental colitis induced by dextran sulfate]

To clarify the mechanisms of action of immunoglobulin (IgG) in intravenous immunoglobulin therapy for the ulcerative colitis (UC) patients, we studied the therapeutic effect of IgG on experimental rat colitis induced by dextran sulfate sodium and on the production of inflammatory cytokines such as TNF alpha, IL-1 alpha and IL-8. The administration of rat IgG demonstrated to suppress the development of blood stool and the induction of the ulcerative lesion in large intestine. The levels of TNF alpha, IL-1 alpha and IL-8 were increased in blood and mucosa of the large intestine in this model. Rat IgG showed a tendency to decrease the levels of the cytokines in colonic mucosa. This result seems to provide a piece of explanation of how massive administration of IgG shows an improvement in the ulcerative lesion of UC patients.

Inactivation and elimination of viruses during preparation of human intravenous immunoglobulin

We report here the results of our evaluation of virus inactivation during the manufacturing steps of two intravenous immunoglobulin (IGIV) preparations. Virus inactivation and/or removal by processing steps, such as ethanol fractionation and polyethylene glycol precipitation, and deliberate virucidal steps, such as solvent/detergent treatment and pasteurization, were tested on a variety of human pathogenic and experimental model viruses, including human immunodeficiency, Hepatitis C, Mumps, Vaccinia, Chikungunya, Vesicular Stomatitis, Sindbis, and ECHO viruses. All viruses were successfully inactivated and/or eliminated by the processing steps studied. In some cases, however, multiple steps were required. We conclude that the incorporation of steps deliberately designed to inactivate or remove viruses during the production of IGIV provides an extra measure of viral safety.

Potent cholesterol-lowering effect by human granulocyte-macrophage colony-stimulating factor in rabbits. Possible implications of enhancement of macrophage functions and an increase in mRNA for VLDL receptor

The mechanism by which granulocyte-macrophage colony-stimulating factor (GM-CSF) lowers plasma cholesterol levels is not well understood. We tested recombinant human GM-CSF (rhGM-CSF) on plasma cholesterol and triglycerides in rabbits and attempted to determine the mechanisms of the cholesterol-lowering effect. rhGM-CSF (20 micrograms.kg-1.d-1) was administered to normal and cholesterol-fed rabbits for 2 weeks and to Watanabe heritable hyperlipidemic (WHHL) rabbits for 1 week. The administration of rhGM-CSF markedly lowered cholesterol and triglycerides, an effect that persisted in normal and cholesterol-fed rabbits even after termination of treatment. The cholesterol-lowering effect of rhGM-CSF was also observed in WHHL rabbits. rhGM-CSF was capable of stimulating granulocyte-macrophage colony formation in vitro in rabbits with an effect comparable to that in humans. Northern blot analysis with rabbit very-low-density-lipoprotein (VLDL) receptor cDNA revealed that rhGM-CSF increased the levels of VLDL receptor mRNA in muscle of rabbits after only 1.5 hours of treatment compared with control (2.6-fold), with the 1.5-fold increase following a 5-day administration. No changes in the levels of LDL receptor mRNA in liver, spleen, and bone marrow were observed in the treated rabbits. These findings suggest that the cholesterol-lowering effect of rhGM-CSF may be mediated by enhancement of macrophage functions in lipid metabolism and the increase in mRNA for VLDL receptor in rabbits.

Tissue distribution of macromolecular conjugate, adriamycin linked to oxidized dextran, in rat and mouse bearing tumor cells

Tissue distribution of the radioactivities after intravenous administration of [14C]adriamycin ([14C]ADM) or [14C]ADM linked to oxidized dextran ([14C]ADM-OXD) in mouse bearing Lewis lung carcinoma (LLC) and rat bearing Walker 256 carcinosarcoma was studied. ADM conjugated with OXD increased plasma half-life and gave high area under the plasma concentration-time curve (AUC). The AUC values were 13.0 and 5.8 times higher than those of the [14C]ADM group in mice and rats, respectively. In the tumor tissues, AUC values of the [14C]ADM-OXD group were also respectively 1.6 and 1.9 times higher than those of the [14C]ADM group. However, the AUC values in the heart of the [14C]ADM-OXD group were about half those of [14C]ADM group in both animals. Thus the distribution of ADM was changed by the conjugation with OXD. The excretion profile of ADM was also changed by the conjugation. During 6 h after administration, [14C]ADM-OXD was mainly excreted into rat urine at 45.2% of the original dose, but in the [14C]ADM group recovery in urinary excretion was 4.2%. Using [14C]ADM-OXD and ADM-[14C]OXD, the respective tissue distribution of ADM and OXD portions in the ADM-OXD was studied in rats bearing Walker 256. The radioactivities of both [14C]ADM-OXD and ADM-[14C]OXD groups increased in tumor and liver within 1 h after administration. In the liver, both radioactivities were retained for 24 h, which suggested that ADM and OXD were retained as conjugated form, however, different behavior was observed between the two groups in tumor tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Application of neurophysiological methods in occupational medicine in relation to psychological performance

Many years ago, we introduced advanced neurophysiological and psychobehavioural methods to our laboratory and have since applied our techniques on workers exposed to various occupational factors. In this article, we summarized our recent findings on the neurophysiological subclinical effects of lead, mixed solvents, toluene, styrene, local vibration and visual display terminal (VDT) work in relation to psychobehavioural effects. The methods used were as follows: 1) cerebral evoked potentials, i.e. short-latency somatosensory and visual evoked potentials (SSEP and VEP) and brainstem auditory evoked potential (BAEP), 2) event-related potential (P300), 3) psychological performance test, 4) computerized static posturography, 5) electrocardiographic R-R interval variability (CVRR), 6) distribution of nerve conduction velocities (DCV), and 7) conventional nerve conduction velocity (NCV). The following results were obtained: 1) Delay in SSEP latency in lead workers, in VEP latency in lead and VDT workers, in BAEP latency in vibrating tool workers and in P300 latency in lead workers, as well as significant correlations of P300 latency with blood lead concentrations in lead workers and of BAEP latency with length of work in brush saw operators; 2) Increase in postural sway and its significant correlation with urinary hippuric acid in toluene workers; 3) Decrease in CVRR in lead, mixed solvent, toluene, styrene and vibrating tool workers, and a significant correlation of the CVRR with length of exposure in mixed solvent workers; 4) Slowing of faster nerve fibre conduction in DCV and of NCV in lead, mixed solvent, styrene and vibrating tool workers, and their correlations with blood lead and length of work in lead and chain saw operators, respectively; 5) Decrease in the score on picture completion test in lead and styrene workers and its correlation with blood lead in lead workers. These findings suggest that recent advances in neurophysiological methods have enabled the detection of subclinical effects of various occupational and environmental factors.

[A new electrode (HN-5) for CM measurement in extra-tympanic electrocochleography]

A new electrode (HN-5) for CM measurement in extra-tympanic electrocochleography (ECochG) has been developed. The electrode consists of a silver wire 2.0 mm in diameter and 5 cm in length connected to a low noise cable. The electrode impedance values were low and the frequency characteristics were excellent. In order to explore various artifacts, the electrode was inserted into a glass cup containing 100 ml of tap water, which served as a dummy ear. A sound stimulus with an intensity of 90 dBnHL was delivered by a shielded loudspeaker located 50 cm from the dummy ear (glass cup). In this dummy test, contamination with measurable artifacts, such as electromagnetic inductions generated by a sound transducer and the CM-like mechanical vibrations which activated the dummy ear acoustically, was kept within the noise levels inherent in the recording system. The CMs were recorded from subjects with normal hearing by placing an electrode adjacent to the postero-inferior rim of the tympanic membrane (annulus tympanicus). Short tone bursts were employed as acousti stimuli and delivered by the shielded loudspeaker. CM detection thresholds were very low and CM-like responses with delayed onset time (delayed CM) were clearly observed at lower stimulus levels. The input-output curves of the CMs and delayed CMs were non-linear. These findings from the CMs did not differ from those obtained by the transtympanic needle electrode technique. Responses obtained had satisfactory S/N ratios and resulted in almost the same average calculations as those with transtympanic ECochG.(ABSTRACT TRUNCATED AT 250 WORDS)

Transforming growth factor beta 1-mediated induction of junB is selectively inhibited by expression of Ad.12-E1A

Transforming growth factor beta (TGF-beta), a multifunctional polypeptide growth factor, regulates the expression of many genes critical to cell cycle progression, such as members of the jun gene family which encode components of the transcription factor complex AP-1. The transforming proteins encoded by the early region 1A of adenovirus12 (Ad.12-E1A) abrogate some of the cellular responses to TGF-beta as well as affecting, differentially, the expression of cellular jun genes. Our data demonstrate that expression of Ad.12-E1A in rat 3Y1 fibroblast cells inhibits induction of junB by TGF-beta 1 while not altering the regulation of junB by phorbol ester or serum. Regulation of c-jun gene expression by TGF-beta 1, phorbol ester, and serum is not appreciably altered by the expression of Ad.12-E1A. Inhibition of TGF-beta induced junB expression is not due to a defect in TGF-beta/receptor interaction on Ad.12-E1A transformed cells and is not observed in other isotypic fibroblast cells transformed by SV40 or polyomavirus. These data suggest that multiple, independent, intracellular signal transduction pathways exist which mediate genomic responses to TGF-beta. Cellular expression of Ad.12-E1A-12S gene products results in selective disruption of some TGF-beta 1 signaling cascades and not those activated by phorbol ester or serum. These data further suggest that some cellular targets which mediate TGF-beta 1 action may also be unique targets of action for the E1A-12S transforming protein of adenovirus12.