[Pharmacokinetic, bacteriological and clinical studies on S-1108 in children]

Pharmacokinetic, bacteriological and clinical studies on S-1108 were performed in children. The results were as follows: 1. A total of 11 patients were treated with S-1108. Each dose was 3 mg/kg, orally administered 3 times daily for 4-14 days. The clinical efficacies of S-1108 in 10 patients with bacterial infections (1 with bacteremia, 4 with pneumonia, 1 with acute maxillary sinusitis, 1 with scarlet fever and 2 with streptococcal pharyngitis) were evaluated as excellent in 8 patients and as good in 2 patients with an efficacy rate of 100%. Only one patient with staphylococcal scalded skin syndrome due to methicillin resistant Staphylococcus aureus (MRSA) who received gamma-globulin was not evaluated. Fourteen causative strains of 5 species were found in 10 patients. Three strains of Streptococcus pneumoniae out of 5, 2 of 3 Branhamella catarrhalis strains, none of Staphylococcus aureus and all 3 strains of Streptococcus pyogenes were eradicated. No adverse reaction was observed in any of the 11 patients. 2. MICs of S-1108 against 5 clinically isolated S. pneumoniae from cases of infections were examined. All of them were relatively highly resistant to penicillins. S-1108 was compared with cefteram pivoxil, cefpodoxime proxetil, cefaclor and cefixime, and it showed better antibacterial activity or than other cephems. 3. Double peaks were obtained in plasma levels of S-1108 orally administered at a dose of 3 mg/kg at 30 minutes after meal and were 1.03 microgram/ml and 0.74 microgram/ml at 1 and 4 hours after administration, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of calcium ion in induction of apoptosis by etoposide in human leukemia HL-60 cells

The epipodophyllotoxin derivative etoposide, an inhibitor of DNA topoisomerase II, has been found to induce internucleosomal DNA fragmentation, characteristic of apoptosis. In the present study, we examined the effect of Ca2+ depletion on VP-16-induced endonucleolytic DNA cleavage in HL-60 cells. VP-16-induced internucleosomal DNA fragmentation could not be blocked by the extracellular Ca2+ chelator EGTA. However, an intracellular Ca2+ chelator BAPTA-AM, which was added after treatment with VP-16, abolished both internucleosomal DNA fragmentation and the morphologic features of apoptosis. No significant increase of intracellular Ca2+ was found after VP-16 treatment. We demonstrate for the first time that preexisting intracellular Ca2+ plays an essential role in induction of apoptosis by VP-16 in HL-60 cells.

Fluorocyclopropyl quinolones. 1. Synthesis and structure-activity relationships of 1-(2-fluorocyclopropyl)-3-pyridonecarboxylic acid antibacterial agents

A series of 1-(2-fluorocyclopropyl)-3-pyridonecarboxylic acids has been prepared. These derivatives are characterized by having a fluorine atom at the 2-position on the cyclopropane ring as the N1 substituent and consist of both cis and trans stereoisomers. Structure-activity relationship studies indicate that the cis derivatives are more potent against Gram-positive bacteria than the corresponding trans counterparts, but the difference in potency against most Gram-negative bacteria is much smaller. The inhibitory effect of compounds 4, 5, 26, 27, 38, and 39 on supercoiling activity of DNA gyrase obtained from E. coli KL-16 correlated with their MICs against the same strain and also depend on their (26, 27, 38, 39) stereochemistry. Introduction of a fluorine atom on the cyclopropyl group resulted in the reduction of lipophilicity compared with the corresponding nonfluorinated quinolones.

A factor binding to the xenobiotic responsive element (XRE) of P-4501A1 gene consists of at least two helix-loop-helix proteins, Ah receptor and Arnt

Xenobiotic responsive element (XRE) is an inducible enhancer element that drives inducible expression of P-4501A1 gene in response to xenobiotic inducers. The XRE-binding factor appears in the nuclei of Hepa-1 cells treated with 3-methylcholanthrene (3-MC). Association of the Ah receptor and Arnt (Ah receptor nuclear translocator) in an XRE-binding complex was examined by anti-Ah receptor and Arnt antibodies. Both antibodies inhibited the sequence-specific XRE-binding activity of nuclear extracts from 3-MC-treated Hepa-1 cells and of the cytosolic fraction which was prepared from the nontreated cells and treated in vitro with 3-MC. These results indicate that Ah receptor and Arnt proteins are components of the XRE-binding factor and suggest that Arnt as well as the Ah receptor are localized in the cytosol of nontreated cells. The Ah receptor present in C4 cells, a mutant of Hepa-1 cells defective in the Arnt function, showed an inducer-dependent association with Arnt synthesized in an in vitro translation system. Co-transfection of the expression plasmids of the Ah receptor and Arnt exhibited synergistically more activated transcription from a reporter gene pMC6.3k consisting of the P-4501A1 gene promoter and enhancer than transfection with either of the two plasmids alone. These findings indicate that the Ah receptor and Arnt proteins form a complex that activates transcription in an inducer-dependent manner.

Differential sensitivity of rat cardiac sarcolemma and mitochondria to damage induced by lipid peroxidation

It is well known that the sarcolemma is the organelle most susceptible to lipid peroxidative attack in the isolated membrane preparations. To determine whether this also occurs in the intact heart, we studied the effect of cumene hydroperoxide, an agent capable of initiating lipid peroxidation, on the ultrastructure and lanthanum (La) staining of isolated rat hearts perfused with HEPES buffer (pH 7.4) containing: 140 mM NaCl, 5 mM KCl, 1 mM MgCl2, 3 mM HEPES, 1.5 mM CaCl2 and 11 mM glucose. No ultrastructural alterations or intracellular deposits of La were observed in myocytes of rats perfused with HEPES buffer. Perfusion with cumene hydroperoxide (0.5 mM) for 30 min induced a release of malondialdehyde-like substance in the perfusate and a spectrum of myocardial ultrastructural alterations. La was always observed only outside the sarcolemma in myocytes with moderate damage consisting of clearing of the mitochondrial matrix and slight margination of chromatin in the nuclei. Intracellular La was found in myocytes with severe and irreversible damages consisting of fragmentation of cristae and electron-dense amorphous particles in mitochondria. La was deposited on the outer surface of the mitochondrial membranes, lipid droplets and myofilaments. These data suggest that mitochondria are more susceptible than is the sarcolemma to lipid peroxidation induced by cumene hydroperoxide in the beating rat heart.

Erythromycin inhibits the production of elastase by Pseudomonas aeruginosa without affecting its proliferation in vitro

Extracellular proteases from Pseudomonas aeruginosa play important roles in infections in the respiratory tract. The effect of erythromycin (EM), a macrolide antibiotic, on the production of elastase by P. aeruginosa was investigated in vitro and compared with the effect of other antibiotics. Thirty-four (94.4%) of thirty-six different strains produced detectable amounts of elastase determined by the gel diffusion method. The elastase production was inhibited completely by EM in 27 (79.4%) of 34 strains at some concentrations between 0.125 and 64 micrograms/ml. At 4 micrograms/ml or less, the elastase production was inhibited completely in four (11.8%) strains and more than 50% in the other 10 (29.4%). At 8 micrograms/ml or less, the elastase production was inhibited completely in 11 (32.4%) strains and more than 50% in the other nine (26.5%). The proliferation was partially inhibited at 32 and 64 micrograms/ml. Roxithromycin inhibited the elastase production at higher concentrations than EM without inhibiting the proliferation. Midecamycin and ampicillin did not inhibit the elastase production or the proliferation. Doxycycline and ticarcillin inhibited the elastase production and/or the proliferation at concentrations greater than 16 micrograms/ml. Although ofloxacin (OFLX) inhibited both the proliferation and the elastase production in parallel at low concentrations, there were six (16.7%) strains resistant to OFLX. Among them the elastase production was inhibited in five strains by EM. These results suggest that EM acts on P. aeruginosa to inhibit extracellular production of elastase without affecting the proliferation of the bacteria.

Expression of glial fibrillary acidic protein in rabbit Müller cells after lensectomy-vitrectomy

PURPOSE

To assess retinal response after lensectomy-vitrectomy, the authors analyzed glial fibrillary acidic protein (GFAP), which retinal glial cells express in several pathologic conditions.

METHODS

GFAP expression was examined by means of immunohistochemistry, Western blot analysis, and enzyme-linked immunosorbent assay (ELISA) in rabbit retina after lensectomy-vitrectomy.

RESULTS

Müller cells had detectable GFAP immunoreactivity in peripheral retina 3 days after surgery. GFAP immunoreactivity was present in both peripheral and posterior regions 7 days, 14 days, and 6 months after surgery. The authors confirmed that anti-GFAP antibody recognized the 51 kDa protein specifically by Western blot analysis. Time-dependent increase of GFAP in peripheral retina was also obtained by ELISA:

CONCLUSIONS

Such progressive GFAP accumulation in Müller cells, which are sensitive to microenvironmental changes, may reflect some underlying retinal response after lensectomy-vitrectomy.

Immunohistochemical studies of S-100 protein expression in myoepithelial cells of benign breast diseases and normal breast tissues

We studied benign breast diseases using polyclonal anti S-100 protein and monoclonal anti a-subunit or beta-subunit of S-100 protein antibodies. The antibody gave positive staining in most of the cytoplasms and nuclei of the myoepithelial cells of normal breast tissues, gynecomastia, fibroadenoma, intraductal papilloma and mastopathy. However, immunohistochemical methods using the monoclonal antibodies for them did not reveal positive staining in the myoepithelial cells.

Ascorbic acid deficiency reduces the level of mRNA for cytochrome P-450 on the induction by polychlorinated biphenyls

Ascorbic acid (AsA) deficiency causes a decrease in hepatic concentration of cytochrome P-450 and a decrease in hepatic activity of drug-metabolizing enzymes in rats unable to synthesize AsA (ODS rats). To study the mechanism of the decrease in hepatic concentration of cytochrome P-450 isozymes by AsA deficiency, we chose the xenobiotics-inducible cytochrome P-450 and performed the experiments indicated below. AsA-deficient rats were fed polychlorinated biphenyls (PCB) which markedly induce both CYP1A subfamily and several isozymes in CYP2B subfamily. First, we assayed the activities of two drug-metabolizing enzymes so that one could be functionally distinguished from another. AsA deficiency significantly reduced the hepatic activity of aminopyrine-N-demethylase in ODS rats with and without dietary PCB, but had no effect on benzo(a)pyrene hydroxylase activity. Secondly, quantitative immunoblot analyses demonstrated that the levels of CYP2B1/2B2 and CYP1A1 in the AsA-deficiency rats fed PCB were approximately 60 and 80% lower than those found in rats fed AsA-supplemented diet. The degree of reduction in CYP2B1/2B2 was greater than CYP1A1. Thirdly, AsA deficiency caused a decrease in hepatic abundance of CYP2B1/2B2 mRNA, whereas it had no effect on the levels of CYP1A1 and 1A2 mRNA. These results indicated that dietary AsA selectively affects the levels of CYP2B1/2B2 mRNA among cytochrome P-450 induced by PCB and plays important roles for optimum induction of drug-inducible cytochrome P-450. We concluded that AsA deficiency decreases specific froms of drug-inducible cytochrome P-450, especially CYP2B1/2B2 and that the reduction of CYP2B1/2B2 mRNA level in AsA-deficient rats caused a decrease in cytochrome P-450 concentration and hepatic activity of drug-metabolizing enzymes.

Regulation of cholesterol metabolism in adrenal cortex: comparative studies on cholesterol esterase in human adrenal glands

We have studied the nature and characteristics of cholesterol esterase (CEase) in human adrenal adenoma and hyperplasia tissues showing Cushing's syndrome, comparing with those in normal tissue. Each tissue demonstrated that two pH optima were found at around 4.5 and 8.0. The results of a subcellular distribution study show that acid and alkaline CEase are mainly located in lysosomes and microsomes, respectively. Our previous data suggested that phosphatidylcholine which was sonicated with cholesteryl oleate as a substrate may play a crucial role in the regulation of CEase in rat adrenal. The effect of phosphatidylcholine was therefore investigated in the present study. Acid CEase in normal tissue was increased in a dose-dependent manner by phosphatidylcholine, but not in the adenoma or hyperplasia tissues. None of those tissues showed any enhancement in alkaline CEase activity when phosphatidylcholine was added to the substrates. It is therefore suggested that the mechanism of regulation of CEase among three different kinds of human adrenals may be different from the data for the effect of phosphatidylcholine. Basal activity of acid CEase in adenoma and hyperplasia was significantly higher than that in normal tissue, and also that of alkaline CEase in hyperplasia tissue was significantly higher than that in normal tissue. Thus it is suggested that such an adrenocortical disorder as Cushing's syndrome due to adenoma and diffuse hyperplasia of the adrenal cortex may possess the nature and characteristics of autonomy of steroidogenesis which seems to be induced by the active metabolism of cholesterol, when compared with normal tissue.

Proton magnetic resonance spectroscopy of vitreal changes in experimental streptococcal endophthalmitis

We used magnetic resonance spectroscopy to examine endophthalmitis in rabbits inoculated with a virulent strain of Streptococcus pneumoniae. On different days after infection, the animals were sacrificed and the vitreous isolated and examined with water-suppressed proton magnetic resonance spectroscopy. A broad resonance corresponding to the methyl envelope of lipoprotein lipids appeared 2 days after infection and persisted until the eyes developed phthisis (around 10 days postinfection). This resonance was absent in the control eye and the bacterial culture; it could be used as the marker of breakdown of blood-vitreous barrier and onset of endophthalmitis-induced changes.

Effect of the rice bran-derived phytosterol cycloartenol ferulic acid ester on the central nervous system

In order to investigate the effect of cycloartenol ferulic acid ester (CFE, CAS 21238-33-5), a component of gamma-oryzanol which is a phytosterol derived from rice bran, on the central nervous system, a variety of pharmacological tests were performed. It was shown that CFE had a suppressant effect on the central nervous system, but its properties were different from those of existing major and minor tranquilizers. In addition, its efficacy in several models of cerebral dysfunction was demonstrated. Since any clear effects could not be obtained under the treatments with gamma-oryzanol, CFE seems to be more useful than gamma-oryzanol. Thus the results of this study suggest that CFE may serve as a new plant-derived cerebral activator possessing a wide range of pharmacological actions.

[Pharmacokinetic, bacteriological and clinical studies on cefditoren pivoxil in children]

Pharmacokinetic, bacteriological and clinical studies on cefditoren pivoxil (CDTR-PI, ME 1207) were performed in children. The results were as follows: 1. A total of 18 patients (19 infections) were treated with CDTR-PI. The doses ranged 2.1-3.2 mg/kg, and it was orally administered 3 times daily, for 4-10 days. Clinical efficacies of CDTR-PI in 18 patients with 19 bacterial infections (3 with tonsillitis, 1 with bronchitis, 7 with pneumonia, 1 with acute maxillary sinusitis, 4 with otitis media, 1 with urinary tract infection, 2 with skin and soft tissue infection) were evaluated as excellent in 13 infections and as good in 6 infections with an efficacy rate of 100%. Twelve causative strains of 5 species were found in 11 patients. Streptococcus pneumoniae in 2 cases out of 3, Haemophilus influenzae in 4/4, Staphylococcus aureus in 2/2, Haemophilus parainfluenzae in 2/2 and Escherichia coli in 1/1 were eradicated. Two patients had mild diarrhea but did not need specific treatment. Severe adverse reaction was not observed in any of the 18 patients. 2. MICs of CDTR were examined against 4 clinically isolated S. pneumoniae strains. Two strains of S. pneumoniae were relatively resistant to penicillins. 3. Pharmacokinetic studies Peak serum CDTR concentrations in 3 patients were 2.38 micrograms/ml, 0.72 micrograms/ml and 2.25 micrograms/ml at a dose of CDTR-PI 3 mg/kg orally administered at 30-minute after meal.(ABSTRACT TRUNCATED AT 250 WORDS)

Anomalous Cloquet's canal in a case of optic nervehead coloboma associated with extensive retinal detachment

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Effect of vasoactive intestinal peptide, somatostatin, and substance P on spontaneous IgE and IgG4 production in atopic patients

The effect of vasoactive intestinal peptide (VIP), somatostatin (SOM), and substance P (SP) on spontaneous human IgE and IgG4 production in atopic patients was studied. In cultures of mononuclear cells (MNC), VIP inhibited both IgE and IgG4 production without affecting IgM, IgA, IgG1, IgG2, or IgG3 production. In contrast, SOM inhibited only IgE production whereas SP inhibited only IgG4 production without affecting production of other isotypes or other IgG subclasses. The effect of neuropeptides was specific because each was specifically blocked by a corresponding neuropeptide antagonist. To achieve the effect noted above, neuropeptides must be added at the start of the culture. IFN-alpha and IFN-gamma were found to inhibit both IgE and IgG4 production whereas prostaglandin E2 (PGE2) inhibited only IgE production. However, the inhibition of IgE and IgG4 production by neuropeptides could not have been mediated by IFN-alpha, IFN-gamma, or PGE2 because the addition of anti-IFN-alpha, anti-IFN-gamma, and indomethacin, respectively, did not reverse the inhibition. In contrast to their effects on MNC, neuropeptides did not affect production of either IgE or IgG4 by purified B cells; the addition of either T cells or monocytes to B cells had no effect on this. However, neuropeptides were effective in inhibiting IgE and IgG4 production by B cells cultured together with both T cells and monocytes. Depletion of sIgE+ and sIgG4+ B cells resulted in abrogation of IgE and IgG4 production, respectively. However, stimulation of sIgE- B cells with IL-4 plus anti-CD 40 mAb induced IgE production, which was inhibited by VIP and SOM, but not SP, in the presence of both T cells and monocytes. These results suggest that neuropeptides inhibited spontaneous IgE and IgG4 production by interaction with sIgE+ and sIgG4+ B cells in a T cell- and monocyte-dependent fashion. In addition, VIP and SOM also inhibited IgE production by modulating switching induced by IL-4 plus anti-CD 40 mAb in a T cell- and monocyte-dependent fashion.

Effect of vasoactive intestinal peptide, somatostatin, and substance P on spontaneous IgE and IgG4 production in atopic patients

The effect of vasoactive intestinal peptide (VIP), somatostatin (SOM), and substance P (SP) on spontaneous human IgE and IgG4 production in atopic patients was studied. In cultures of mononuclear cells (MNC), VIP inhibited both IgE and IgG4 production without affecting IgM, IgA, IgG1, IgG2, or IgG3 production. In contrast, SOM inhibited only IgE production whereas SP inhibited only IgG4 production without affecting production of other isotypes or other IgG subclasses. The effect of neuropeptides was specific because each was specifically blocked by a corresponding neuropeptide antagonist. To achieve the effect noted above, neuropeptides must be added at the start of the culture. IFN-alpha and IFN-gamma were found to inhibit both IgE and IgG4 production whereas prostaglandin E2 (PGE2) inhibited only IgE production. However, the inhibition of IgE and IgG4 production by neuropeptides could not have been mediated by IFN-alpha, IFN-gamma, or PGE2 because the addition of anti-IFN-alpha, anti-IFN-gamma, and indomethacin, respectively, did not reverse the inhibition. In contrast to their effects on MNC, neuropeptides did not affect production of either IgE or IgG4 by purified B cells; the addition of either T cells or monocytes to B cells had no effect on this. However, neuropeptides were effective in inhibiting IgE and IgG4 production by B cells cultured together with both T cells and monocytes. Depletion of sIgE+ and sIgG4+ B cells resulted in abrogation of IgE and IgG4 production, respectively. However, stimulation of sIgE- B cells with IL-4 plus anti-CD 40 mAb induced IgE production, which was inhibited by VIP and SOM, but not SP, in the presence of both T cells and monocytes. These results suggest that neuropeptides inhibited spontaneous IgE and IgG4 production by interaction with sIgE+ and sIgG4+ B cells in a T cell- and monocyte-dependent fashion. In addition, VIP and SOM also inhibited IgE production by modulating switching induced by IL-4 plus anti-CD 40 mAb in a T cell- and monocyte-dependent fashion.

DNA damage and cell killing by camptothecin and its derivative in human leukemia HL-60 cells

Camptothecin (CPT) has been recognized as a topoisomerase I (Topo I) inhibitor. However, the mechanism of cytotoxicity of this agent remains unknown. In the present study, we analyzed the kinetics of Topo I-mediated DNA single-strand breaks and internucleosomal DNA cleavage produced by CPT and its derivative, 7-ethyl-10-hydroxycamptothecin (SN-38), in HL-60 cells. DNA single-strand breaks were detected using alkaline sucrose gradient centrifugation when HL-60 cells were incubated with 10 microM CPT or 10 microM SN-38 for 30 min. These DNA single-strand breaks were rapidly repaired after drug removal, while the cytotoxic action of these drugs was sustained. Treatment of HL-60 cells with CPT or SN-38 for 3 h produced extensive degradation of DNA. Agarose gel electrophoresis showed a ladder of DNA fragments consisted of multimers of approximately 200 base pairs, characteristic of apoptosis. Interestingly, this type of DNA fragmentation was also induced within 4 h after repair of DNA single-strand breaks, and subsequently loss of cell viability was observed. When zinc ion, a potent inhibitor of endonuclease, was added to drug-free medium after treatment with CPT or SN-38, internucleosomal DNA cleavage was abolished. Furthermore, addition of zinc ion reduced the loss of cell viability. These data suggest that Topo I-mediated DNA single-strand breaks may be necessary but are not sufficient for cell death, and the endonuclease involved in induction of internucleosomal DNA cleavage may play an important role in HL-60 cell death induced by Topo I inhibitor.

Increased mechanical extraction of T-tubule/junctional SR from cardiomyopathic hamster heart

We determined the contents of L-type calcium channels (LCC) and other membrane proteins in ventricular homogenates and microsomes prepared from hearts of 30- to 70-day-old Syrian cardiomyopathic (Bio 14.6) and normal hamsters. Quantitative immunoblot assay revealed that myopathic microsomes, as compared with normal controls, were enriched about twofold with the alpha 1-subunit of LCC, the ryanodine receptor calsequestrin, and Na(+)-K(+)-adenosinetriphosphatase (ATPase), whereas the contents of these proteins in ventricular homogenates were not different. In contrast, Na(+)-H+ antiporter and sarcoplasmic reticulum (SR) Ca(2+)-ATPase showed no difference in their contents in both homogenates and microsomes. Radioligand binding assay further showed no significant difference in the number of binding sites for [3H]prazosin, [125I]iodocyanopindolol, and [3H]saxitoxin between myopathic and normal microsomes. These result suggest that whereas membrane densities of LCC and the other proteins examined are not increased in myopathic cardiomyocytes, T-tubule/junctional SR membranes are more easily extracted from them by mechanical disruption. This, together with 1.5-fold higher yield of microsomal fractions from myopathic heart muscle, shows that abnormality exists in the mechanical property of cell membrane in the myopathic heart.

5' structure and expression of human glucose-6-phosphate dehydrogenase mRNA

The human glucose-6-phosphate (G6PD) cDNAs cloned from normal and carcinoma cells can encode 545-amino-acid residues starting from the first in-frame chain initiation codon. However, it was reported that the G6PD mRNAs of carcinoma cell lines were shorter and could encode only 515-amino-acid residues (Martini et al., 1986). We demonstrated the existence of two major G6PD mRNAs in normal reticulocytes, lymphoblasts, and hepatocytes by the primer extension analysis. The longer mRNA has a cap site at approx. nucleotide -166 and can encode 545-amino-acid residues, whereas the shorter mRNA has a cap site at approx. nucleotide -66, and encodes 515-amino-acid residues. These two naturally existing mRNAs (cDNAs) and an artificially truncated mRNA, which can encode the carboxy-terminal 479-amino-acid residues of the subunit, were expressed in the in vitro reticulocyte and wheat germ systems and in the in vivo E. coli system. All three species of mRNA (cDNA) were efficiently translated and produced proteins with the expected molecular sizes. The peptide with 515 residues formed the catalytically active enzyme, but the 545-residue protein and the 479-residue protein were catalytically inactive. The larger 545-residue protein may correspond to the larger G6PD precursor observed in the rat. The extended amino-terminal region encoded by the larger mRNA contains the -Arg-Gly-Gly-Arg-Arg-Arg-Arg-sequence, which is conserved in the nucleotide-binding protamine family.

[A retrospective cohort study on long-term health effects of shift work]

A retrospective cohort study was conducted to examine the long-term effects of shift work including night work upon sick leave utilization. The cohort consisted of all blue-collar workers aged 16 to 28 years, who entered a steel production plant between 1967 and 1970, who were then divided into a shift worker group (790 persons) and a day worker group (309 persons) according to their initial baseline work pattern. A 20 year follow-up study of the health administration files of the two groups was performed in November 1991. The main results were as follows: 1. Reasons for and time trends for retirements in the shift worker group were very similar to those in the day worker group. 2. With respect to illnesses needing hospitalization or medically certified absence lasting more than one month, the cumulative incidence rates during a 5-year period and a 10-year period in the shift worker group were 17% and 28% respectively, and 16% and 28% in the day worker group. No significant effect of shift work upon occurrence of illnesses could be found after controlling for factors at entrance and history of engagement in hazardous work although there were differences between the two groups. 3. No significant differences in incidence rates of any diagnostic categories were detected between the groups. 4. Among the workers still employed in 1990, we found no differences in prevalence rates of any diagnostic categories between the groups. These results lead to the conclusion that shift work appears to have no severe adverse effects upon morbidity when there is a high level of health and labor administration.

Tumor induction by concurrent oral administration of ethylenethiourea and sodium nitrite in mice

Carcinogenic potential of ethylenethiourea (ETU) in combination with sodium nitrite was investigated in ICR mice of both sexes. Groups of 30 males and 30 females each were given 10 weekly oral administrations of ETU and sodium nitrite with the following combinations of dosing (ETU vs sodium nitrite, mg/kg/wk): 0 vs 0, 100 vs 0, 0 vs 70, 25 vs 17.5, 50 vs 35, and 100 vs 70. Thereafter, the animals were allowed to live without treatment up to 18 mo after the first administration. Concurrent administration of ETU and sodium nitrite caused earlier development of tumors and/or dose-dependent increases in the incidences of tumors in the lymphatic tissue, lung, forestomach, Harderian gland, and uterus, whereas treatment with either ETU or sodium nitrite failed to show carcinogenic activity. In addition, carcinomas in the forestomach and uterine horn were limited to mice receiving concurrent administrations of ETU and sodium nitrite. These results indicate that ETU is most probably converted in vivo into N-nitroso ETU and that the N-nitroso ETU has a greater carcinogenic potential in mice than ETU alone.

Regulation of cholesterol metabolism in adrenal cortex: effects of apoproteins on cholesterol esterase in rat adrenal glands

We have investigated the effects of apoproteins on cholesterol esterase (CEase) in rat adrenal glands in order to clarify the mechanism of synthesis of free cholesterol which is the most important substrate for steroidogenesis. We prepared lipid mixtures containing cholesteryl oleate plus apoproteins with and without phosphatidylcholine as a substrate for CEase in order to investigate the effect of the substrate state on CEase. The substrate containing only cholesteryl oleate and apo-HDL increased both acid and alkaline CEase activities. Both acid and alkaline CEase activities were also increased by a substrate containing apo-HDL plus cholesteryl oleate and phosphatidylcholine more than by a substrate containing cholesteryl oleate plus apo-LDL with phosphatidylcholine or cholesteryl oleate with phosphatidylcholine. We have already reported that phosphatidylcholine is an important factor for the regulation of adrenal CEase. Therefore, the present studies show that apoproteins as well as phosphatidylcholine may be important factors for the regulation of adrenal CEase.

Synaptic connections of a periodontal primary afferent neuron within the subnucleus oralis of the cat

The central axon of a primary afferent neuron that responded to light mechanical stimulation of the lower premolar teeth in a fast adapting fashion was intra-axonally injected with horseradish peroxidase in the cat. The labeled terminals within the rostrodorsomedial (Vo.r) and dorsomedial (Vo.dm) parts of subnucleus oralis were examined electron microscopically. The labeled ending had pale axoplasm, contained clear spherical synaptic vesicles, and formed multiple synapses with dendrites and/or unlabeled axonal endings with pleomorphic vesicles (P-endings). In these synaptic contacts, the labeled primary ending was presynaptic to dendrites and postsynaptic to P-endings. Labeled endings simultaneously synapsing with both dendrites and P-endings were more frequent in Vo.dm (28%) than in Vo.r (8.3%).