Capillary zone electrophoretic chiral discrimination using a cationic cyclodextrin derivative: determination of velocity and association constants of each enantiomer of the amino acid derivative with 6-trimethylammonio-deoxy-beta-cyclodextrin

A positively charged beta-cyclodextrin possessing a trimethylammonio group, 6-trimethylammonio-6-deoxy-beta-cyclodextrin chloride 1 was prepared by the reaction of an amino derivative 3 with methyl iodide under very mild conditions. The cyclodextrin derivative discriminated between enantiomers of acetylphenylalanine 2 on capillary zone electrophoresis (CZE) analysis, which was possibly due to an electrostatic interaction between the trimethylammonio group of 1 and the carboxylate group of 2, and also due to the inclusion of 2 in a hydrophobic molecular cavity of 1. Double data normalization based on relative electrophoretic velocity of peaks due to indirect response of 1 and also water in an injected sample may be effective for elimination of variation and fluctuation of physical parameters of medium, such as viscosity and ionic strength, in order to determine intrinsic association constants and velocity of the complexes.

The NPK1 mitogen-activated protein kinase kinase kinase is a regulator of cell-plate formation in plant cytokinesis

Mitogen-activated protein kinase (MAPK) cascades play important roles not only in the transduction of extracellular signals but in the progression of the cell cycle. However, evidence for their role in cytokinesis is limited. Here, we show that a tobacco MAPK kinase kinase (MAPKKK), designated NPK1, is required for cytokinesis. The activity of NPK1 increases in the late M phase of the tobacco cell cycle. During expansion of a new cross-wall (cell plate) toward the cell cortex, NPK1 is consistently localized to the equatorial zone of the phragmoplast, the cytokinetic apparatus where the cell plate is formed. Expression of a kinase-negative mutant of NPK1 results in the generation of multinucleate cells with incomplete cell plates. Phragmoplasts can be formed, but its expansion toward the cell cortex is also blocked. Thus, our results indicate that the NPK1 MAPKKK is essential for the formation of the cell plate, especially for its lateral growth.

A rise of the serum level of von Willebrand factor occurs before clinical manifestation of the severe form of ovarian hyperstimulation syndrome

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) appears to be caused by increased capillary permeability in the vascular endothelial cells. Such cells secrete excess amounts of von Willebrand factor (vWF), a large adhesive glycoprotein.

METHODS

We retrospectively evaluated the circulating levels of vWF and of vascular endothelial growth factor (VEGF) twice, on the days of oocyte retrieval and embryo transfer, in 46 women who developed early-onset OHSS.

RESULTS

Nineteen, 14, and 13 women developed mild, moderate, and severe OHSS, respectively. Inconsistent changes were observed in the VEGF during oocyte retrieval and embryo transfer. However, the net increase in serum vWF during that period showed an increase in absolute value at the time of embryo transfer that paralleled an increase in the severity of OHSS. That is, in mild OHSS, the serum vWF increased from 140 +/- 44 to 164 +/- 28%; in moderate OHSS, it increased from 113 +/- 47 to 186 +/- 22%; and in severe OHSS, it increased from 120 +/- 35 to 274 +/- 63%. All 9 women with a vWF level > 230% at embryo transfer developed severe OHSS, while 9 of 13 women with severe OHSS exhibited a vWF > 230% at embryo transfer.

CONCLUSION

The results suggest that a rise of the serum level of vWF occurs prior to clinical manifestation of OHSS in patients with severe OHSS but not in patients with mild OHSS.

Characterization of a novel triphosphonooctaosylceramide from the eggs of the sea hare, Aplysia kurodai

We have reported the existence of a triphosphonoglycosphingolipid, EGL-I, in the eggs of a sea gastropod, Aplysia kurodai [Yamada, S., Araki, S., Abe, S., Kon, K., Ando, S., and Satake, M. (1995) J. Biochem. 117, 794-799]. We have now isolated a novel glycosphingolipid, named EGL-II, from the eggs of Aplysia. By component analysis, sugar analysis, permethylation studies, fast atom bombardment-mass spectrometry, secondary ion mass spectrometry, and proton magnetic resonance spectrometry, its structure was revealed to be as follows: Galalpha1-->3(GlcNAcalpha1-->2)Galalpha1-->3(3-O-MeGalalpha1-->2)Galalpha1-->3[6'-O-(2-aminoethylphosphonyl)Galalpha1-->2](2-aminoethylphosphonyl-->6)Galbeta1-->4(2-aminoethylphosphonyl-->6)Glcbeta1-->1ceramide. The major aliphatic components of the ceramide are palmitic acid, stearic acid, and anteisononadeca-4-sphingenine.

The structure of physalin T from Physalis alkekengi var. franchetti

A new steroidal constituent named physalin T (3) was isolated from the aqueous extract of Physalis alkekengi var. francheti. Based on 1H and 13C NMR spectral studies the structure was assigned as 2,3-dihydrophysalin D, i.e., 5alpha,6beta-dihydroxy-2,3,5,6-tetrahydrophysalin B, which is the first example of a natural physalin possessing a saturated ring A moiety. The structure was confirmed by the chemical transformation from the known physalin D (2) to physalin T.

Job strain, social support in the workplace, and haemoglobin A1c in Japanese men

OBJECTIVES

To examine the association between job strain (defined in the model of job demands and job control) and social support at the workplace with levels of glycosylated haemoglobin A1c (HbA1c)

METHODS

All male employees aged 40-60 in a manufacturing firm, Japan, were invited to take part in the study. A blood sample was taken from the participants and HbA1c (%) was measured. Job strain and social support at the workplace were assessed with the job content questionnaire (JCQ). After excluding those who had a history of diabetes mellitus or other chronic diseases, data from 268 male day workers were analyzed.

RESULTS

Age adjusted average concentrations of HbA1c were significantly higher in the highest quartile group of job strain or the lowest quartile group of social support at the workplace (p<0.05). Multiple linear regression analysis indicated that job strain was significantly and positively related to HbA1c (p<0.05), whereas social support at the workplace was significantly and negatively related to HbA1c (p<0.05), both after controlling for other covariates.

CONCLUSIONS

Greater job strain and lower social support at the workplace may be associated with increased concentrations of HbA1c. Increased blood glucose may be a physiological mediator between job strain or social support at the workplace and coronary heart disease.

Validity and reliability of a revised Japanese version of the Arthritis Impact Measurement Scales version 2 (AIMS2)

Abstract This study aims to evaluate the validity and reliability of a Japanese version of the Arthritis Impact Measurement Scales, version 2 (AIMS2) for patients with rheumatoid arthritis (RA). The Japanese version of the AIMS2 questionnaire was administered to 1643 patients with classical or definite RA at 11 hospitals nationwide in Japan. Reliability was assessed by a test-retest procedure, 4 weeks apart, using 75 randomly selected patients. Internal consistency was measured by Cronbach's α, and factor analysis was used to obtain the proportion of variance explained by the first factor in principal component analysis. The validity of the AIMS2 scales was assessed by internal standards. Internal consistency (α coefficients, 0.84-0.94), test-retest reliability (intraclass correlation coefficients, 0.75-0.93), and factor analysis (0.62-0.85) of the AIMS2 health status scales proved that they are highly reliable in the Japanese version. Validity, as measured by the relationships among the scores on the questionnaire items, was also sufficiently secured. The validity and reliability of the Japanese version of the AIMS2 are sufficient for all practical purposes when compared with the original and with other translated versions of the questionnaire.

Immunohistochemical analysis of brainstem lesions in infantile spasms

Whether the cerebral or subcortical lesions are involved in the pathogenesis in infantile spasms (IS) remains to be determined. To investigate the functional lesions of the subcortical structures in IS, the brainstem expression of neurotransmitters, neuropeptides and calcium-binding proteins in IS autopsy cases of lissencephaly and of perinatal hypoxic ischemic encephalopathy (HIE/IS) was investigated. The IS patients consisted of four subjects each of lissencephaly and HIE. They suffered from both West and Lennox-Gastaut syndromes. The healthy and disease controls were composed of four subjects without neuromuscular disorders and six cases of HIE (HIE/C), neither of whom had the epileptic syndrome. In these subjects the expressions of tryptophan hydroxylase (TrH), tyrosine hydroxylase (TH), parvalbumin (PV), methionine-enkephalin (ME) and substance P (SP) were immunohistochemically determined in serial sections of the midbrain, pons and medulla oblongata. The immunoreactivity of neurons and neuronal processes for TH was altered in the mesencephalic periaqueductal gray matter, locus ceruleus, and dorsal vagal nucleus in the patients. The HIE/IS cases showed reduced TrH-immunoreactivity in the medullary raphe nuclei. The brainstem auditory tract was poorly discernible on anti-PV immunostaining in the IS patients. The immunoreactivity for ME in the spinal trigeminal nucleus was severely affected in the IS patients, while that for SP was comparatively well preserved. It is suggested that the presence of common brainstem lesions in IS is irrespective of etiologies. It is intriguing that some of the changes seemed to be interrelated with the neurophysiological abnormalities being reported in IS patients.

Polymorphisms of human paraoxonase 1 gene (PON1) and susceptibility to diabetic nephropathy in type I diabetes mellitus

AIMS/HYPOTHESIS

Oxidative stress is a putative mechanism in the development of diabetic nephropathy. Paraoxonase gene 1 is an HDL-bound enzyme that protects tissues against oxidative damage. Three common polymorphisms of paraoxonase gene 1, T-107C in the promoter, Leu54Met and Gln192Arg, that modify paraoxonase activity have been associated with cardiovascular disease. This study aimed to find whether these polymorphisms also contribute to the development of diabetic nephropathy.

METHODS

The association between diabetic nephropathy and these three polymorphisms was examined in a case-control study. For this purpose, genomic DNA was collected from 188 patients with Type I (insulin-dependent) diabetes mellitus and diabetic nephropathy and from 179 unrelated patients with Type I diabetes but without diabetic nephropathy despite the duration of diabetes of 15 or more years.

RESULTS

The genotype and allele frequencies for each of the three polymorphisms (T-107C, Leu54Met and Gln192Arg) were similar in cases and control subjects.

CONCLUSION/INTERPRETATION

The three polymorphisms in paraoxonase gene 1 that have been associated with serum levels of paraoxonase are not associated with diabetic nephropathy. We show that this genetically determined component of the antioxidant capacity of HDL does not play a critical part in the development of diabetic nephropathy.

APOE polymorphisms and the development of diabetic nephropathy in type 1 diabetes: results of case-control and family-based studies

The goal of this study was to examine the association between known polymorphisms in the apolipoprotein E gene (APOE) and diabetic nephropathy (DN) in type 1 diabetes. We used both a case-control comparison and a family-based study design known as the transmission/disequilibrium test (TDT). For the case-control comparison, we collected DNA from 223 subjects with clinically diagnosed DN and 196 control subjects with normoalbuminuria and long-duration type 1 diabetes (> or = 15 years). For the family-based study, we obtained DNA from both parents of 154 DN subjects and 81 control subjects. The frequency of the epsilon2 allele of exon 4 of APOE was significantly higher in DN subjects than in control subjects. The risk of DN was 3.1 times higher (95% CI 1.6-5.9) in carriers of this allele than in noncarriers. In the family study, heterozygous parents for the E2 allele preferentially transmitted epsilon2 to DN offspring (64 vs. 36%, P < 0.03). Four additional polymorphisms (i.e., -491 A/T, -219 G/T, IE1 G/C, and APOCI insertion/deletion [I/D]) that flank the APOE locus were not associated with DN in either the case-control comparison or in the family-based study. In conclusion, the results of the case-control as well as the family-based study provide evidence that the epsilon2 allele of APOE increases the risk of DN in type 1 diabetes. The molecular mechanisms underlying this risk are unclear at present.

cDNA cloning and characterization of vascular apoptosis-inducing protein 1

Hemorrhagic snake venom induces apoptosis in vascular endothelial cells (VEC). In previous reports, we described the purification from crude venom of Crotalus atrox of two vascular apoptosis-inducing proteins (VAP1 and VAP2) that specifically induce apoptosis in vascular endothelial cells. We report here the cDNA cloning and characterization of VAP1. VAP1 cDNA encoded a protein with 610 amino acid residues. The amino acid sequence predicted from the cDNA indicated that VAP1 belongs to the metalloprotease/disintegrin family and that it is a multidomain polypeptide with a proprotein domain, a metalloprotease domain, a disintegrin-like domain, and a cysteine-rich domain. In the disintegrin-like domain, the sequence DECD replaces the RGD sequence that has frequently been found in such domains. We demonstrated that VAP1 has Zn(2+)-dependent metalloprotease activity and degrades fibrinogen. After incubation in the presence of either EDTA or EGTA, VAP1 was hardly able to degrade fibrinogen and to induce apoptosis in VEC. Our results indicated that VAP1 is a new type of snake venom metalloprotease/disintegrin and suggest that the metalloprotease activity of VAP1 might be involved in the induction of apoptosis by VAP1 in VEC.

[A patient of infantile polymyositis triggered by respiratory syncytium virus infection]

An 11-month-old boy developed acute polymyositis about 1 week after respiratory syncytium virus (RSV) pneumonia. He was admitted to our hospital because of interstitial pneumonia. RSV infection was confirmed by the presence of its antigen in his nasal discharge. Two weeks later, his chest X-ray findings improved and RSV antigen became negative, but severe generalized muscle weakness developed, causing respiratory failure. Muscle biopsy demonstrated inflammatory cellular infiltration with occasional fiber necrosis. Intravenous steroid pulse therapy was remarkably effective resulting in complete recovery of his muscle power. In this patient polymyositis was preceded with RSV infection, suggesting a close relationship between polymyositis and RSV infection. Although many patients of viral myositis have been reported to be associated with coxsackie B, HCV and HTLV-1 viruses, our patient is the first infantile polymyositis secondary to RSV infection.

Effects of occupational metallic mercury vapour exposure on suppressor-inducer (CD4+CD45RA+) T lymphocytes and CD57+CD16+ natural killer cells

OBJECTIVES

To examine the effects of metallic mercury vapour on the cellular and humoral immune system.

METHODS

We measured T lymphocyte and natural killer (NK) cell subpopulations, B lymphocytes, and serum immunoglobulins (i.e. IgG, IgA and IgM) together with total T (CD3 +) lymphocytes and total lymphocytes in blood samples from 20 male, fluorescent-lamp makers (mercury workers) and the same number of gender-, age- and smoking-matched controls. Urinary concentrations of inorganic mercury (UHg) in the 20 workers ranged from 1.8 to 163.5 (mean 44.8) microg/l. They had been exposed to mercury vapour for 4 to 62 (mean 31) months.

RESULTS

Numbers of CD4+CD45RA+ (suppressor-inducer) T lymphocytes and total CD4+ T lymphocytes in the mercury workers were significantly smaller than those in the controls (paired-sample t-test, P < 0.01). The number of CD57+CD16+ NK cells was inversely correlated with UHg.

CONCLUSION

It is suggested that numbers of CD4+CD45RA+ T lymphocytes and CD57+CD16+ NK cells are inversely affected by exposure to metallic mercury vapour in workers, with an average urinary inorganic mercury concentration of 45 microg/l being found.

Nocturnal enuresis and the pontine reticular formation

OBJECTIVES

To assess the previously proposed hypothesis that enuretic patients have a dysfunction in the pontine reticular formation.

METHODS

In 18 patients with intractable nocturnal enuresis, rapid eye movement (REM)-related phasic chin muscle activity loss in REM sleep was examined by means of a single-night polysomnography.

RESULTS

In 5 of 18 patients, this physiologically seen phenomenon was found to be disturbed.

CONCLUSIONS

Since REM-related phasic chin muscle activity loss is disturbed by the functional impairment in the pontine reticular formation, some enuretic patients could be considered as presenting a dysfunction in this structure.

1-Methyl-3-isobutylxanthine delays apoptosis induced by deprivation of growth factors in vascular endothelial cells

AIM

To investigate the effects of 1-methyl-3-isobutylxanthine (MIBX) on apoptosis induced by deprivation of acidic fibroblast growth factor (aFGF) and serum in vascular endothelial cells (VEC).

METHODS

Nuclear fragmentation was observed by fluorescence microscopy. Viability was determined by counting the cells that attached to dishes after treatments. DNA fragmentation was measured by agarose gel electrophoresis.

RESULTS

The cells deprived of aFGF and serum were treated with MIBX 25-200 mumol/L for 3, 6, 9, and 12 h, respectively. Morphological changes including the formation of apoptotic bodies and DNA fragmentation of these cells were significantly suppressed by IBMX 50-200 mumol/L at 3 h and 6 h. But after 12-h treatment, no difference was observed between the treated and untreated cells.

CONCLUSION

MIBX delays apoptosis of vascular endothelial cells induced by deprivation of aFGF and serum.

Pathology of familial amyloidotic polyneuropathy with TTR met 30 in Kumamoto, Japan

Seventeen autopsy and 12 sural nerve biopsy cases of familial amyloidotic polyneuropathy (FAP) with transthyretin (TTR) Met 30 were examined clinicopathologically. In the autopsy cases, amyloid deposits were prominent in the peripheral nerve tissues, autonomic nervous system, choroid plexus, cardiovascular system and kidneys. Amyloid involvement in the posterior and anterior roots of the spinal cord, spinal ganglia, thyroid and gastrointestinal tract were also frequent. In the sural nerve biopsy, degenerative changes corresponding in degree to the duration of the clinical course were observed in the endoneurium, and amyloid deposition occurred around the blood vessels. Electron microscopy revealed degenerative changes in the axon, myelin sheath and Schwann cells. The morphometric study showed decreased numbers of small-caliber myelinated fibers during the early stage. TTR was confirmed immunohistochemically as a major component of amyloid deposits. In transgenic mice carrying the human mutant TTR gene, amyloid deposition was observed in various organs except in the peripheral nerves and choroid plexus. Liver transplantation therapy to FAP patients has been carried out and future follow-up studies should investigate the effects of therapy.

Influence of monopoly privatization and market liberalization on smoking prevalence in Japan: trends of smoking prevalence in Japan in 1975-1995

AIMS

In Japan, smoking prevalence in males has been among the highest among industrialized countries, while the prevalence in females has remained relatively low. There have been long-term declining trends since the early 1970s. In the mid-1980s, the public tobacco monopoly was privatized and the tobacco market was liberalized in Japan. This study examines whether the trends in smoking prevalence changed at the time of these market changes.

DESIGN AND MEASUREMENTS

Smoking prevalence data, tabulated by age group and sex, were plotted over the period 1975-95. Trends of smoking prevalence were then analyzed by using linear regressions, and their changes at the time of monopoly privatization and market liberalization were examined by Chow tests.

FINDINGS

The trends in smoking prevalence changed at the time of the monopoly privatization and trade liberalization in both males and females, except for the males in their twenties and thirties. Rates of decline in smoking prevalence diminished in many age groups and prevalence for younger females started to increase.

CONCLUSIONS

Market changes, that result from the privatization of a public tobacco monopoly and trade liberalization, may adversely affect smoking prevalence in many age groups and in both sexes, unless effective countermeasures are taken.

Emulsifying ability of porphyran prepared from dried nori, Porphyra yezoensis, a red alga

A suspension of low-quality dried nori processed from Porphyra yezoensis, a red alga, was autoclaved at 120 degrees C for 30 min, and from the supernatant, five preparations of porphyran of differing molecular masses and chemical compositions were obtained by preprecipitation with ethanol at stepwise-increasing concentrations of 50 and 67% followed by size-exclusion chromatography. The porphyran preparations exhibited a high emulsifying activity index and high emulsion stability over a wide range of pH and temperature and also in the presence of sodium chloride. An adequately high coefficient of correlation between the median diameter of oil droplets and their 3,6-anhydrogalactose content suggests that 3,6-anhydrogalactose could take part in emulsification with porphyran.

Magnetic order in the heavy fermion compound CeCu6 at mK temperatures

We have measured the ac magnetic susceptibility in various fields and thermal expansion of single crystals of the heavy fermion compound CeCu6 at temperatures down to 250 &mgr;K. The susceptibility of CeCu6 shows a peak at about 2 mK and has a large anisotropy. We also detected an anomaly of thermal expansion at the same temperature. The observed behaviors of the susceptibility and the thermal expansion in CeCu6 indicate the occurrence of an antiferromagnetic order.

IL-1 induces expression of p21(WAF1) independently of p53 in high-passage human embryonic fibroblasts WI38

We tested the effect of IL-1 on the expression of p21(WAF1) in human embryonic fibroblasts WI38. Exposure to IL-1 caused induction of p21(WAF1) protein in high-passage WI38 cells but not in early-passage cells. However, IL-1 did not stimulate the transcription of a CAT-reporter gene having two copies of the p53-responsive element on its promoter or the p53-binding capacity of nuclear extracts, although it increased transcriptional rate of p21(WAF1) in these high-passage cells. These results suggest that the induction of p21(WAF1) by IL-1 occurs at the transcriptional level, but p53 function is not required in these cells. Further studies found that IL-1 did not cause cell-cycle arrest, and the overexpression of p21(WAF1) resulted in only a slight delay of cell growth, while the level of p21(WAF1) coprecipitated with cyclin-dependent kinase-2 (Cdk2) was increased by IL-1. Moreover, a kinase assay of Cdk2 immunoprecipitates showed that IL-1 did not reduce the kinase activity, and IL-1 did not affect the status of phosphorylation of the retinoblastoma gene product (Rb). These findings imply that despite the induction of p21(WAF1), this cannot fully account for the growth arrest in high-passage WI38 cells. Thus, IL-1 mediates p21(WAF1) induction through a p53-independent pathway(s) in high-passage WI38 cells, but the cell cycle is regulated independently of p21(WAF1).

Chromosome analysis of human spermatozoa from an oligoasthenozoospermic carrier for a 13;14 Robertsonian translocation by their injection into mouse oocytes

We present a case of a 46,XY der(13;14) Robertsonian translocation carrier whose spermatozoa were karyotyped after injection into mouse oocytes. Fresh semen samples as well as recovered samples were used. There was no significant difference in the survival rate of mouse oocytes (fresh: 78.1% versus frozen: 81.7%), activation rate (fresh: 84.0% versus frozen: 90.6%), fertilization rate (fresh: 72.0% versus thawing of frozen: 76.5%) between fresh or frozen spermatozoa. Metaphase chromosome spreads from 45 spermatozoa were analysed. The frequency of spermatozoa that were chromosomally unbalanced with respect to the translocation was 8.9%, and the frequency of abnormalities unrelated to translocation was 4.4%. An excess of spermatozoa with balanced chromosomes was observed: compared with normal, 23 (51.1%) versus 16 (35.6%) respectively; but this segregation difference was not statistically significant (chi(2) = 0.9, P > 0.3). After genetic counselling with the carrier and his partner, intracytoplasmic sperm injection treatment was performed. Healthy female and male infants were delivered at 36 weeks gestation via a Caesarean section. Both babies were carriers for the balanced Robertsonian translocations detected for prenatal diagnosis at 16 weeks gestation. The present study demonstrates that patients can be given further information about the proportion of the spermatozoa which carry a chromosomal abnormality.

Decrease of glucose utilization rate in the spinal cord of experimental 2,5-hexanedione poisoning rats: application of microdetermination technique

To examine the effects of 2,5-hexanedione (HD) on the glucose metabolism in the spinal cord, glucose utilization rate (GUR) and distribution volume of glucose (DV) were measured in the white matter and anterior horn of the spinal cord in 8 rats exposed to HD for 4 weeks and in 10 control rats. The GUR and DV were determined by the quantitative microdetermination method using non-tracer 2-deoxyglucose based on the three-compartments model of Sokoloff. GURs in the white matter and anterior horn and DV in the anterior horn in the HD-exposed rats were significantly lower than those in the control rats. In the multiple regression analysis, GUR in the white matter of HD-exposed rats was significantly related to blood HD concentration. It is suggested that the decrease of GUR in the white matter is a major effect of HD in the spinal cord.

Alteration of glucose metabolism in the spinal cord of experimental lead poisoning rats: microdetermination of glucose utilization rate and distribution volume

To examine the effects of lead on glucose metabolism in the spinal cord, glucose utilization rate (GUR) and distribution volume of glucose (DV) in the anterior horn and white matter were determined in 9 rats exposed to lead for 4 weeks and 10 control rats. The GUR and DV were determined by the quantitative microdetermination method using non-tracer amount of 2-deoxyglucose based on the three-compartments model of Sokoloff. The GUR and DV in the anterior horn in the lead-exposed rats were significantly lower than those in the controls. It is thus suggested that glucose metabolism, as measured by the GUR and DV, in the anterior horn is inhibited by lead; the anterior horn cells seem sensitive to lead neurotoxicity.

Circadian rhythms of seven heavy metals in plasma, erythrocytes and urine in men: observation in metal workers

To elucidate circadian rhythms (variation within a day) of 7 toxic or essential metals in plasma and erythrocytes in relation to the rhythms in urine in men, 19 male metal foundry workers were examined; they were exposed to lead (Pb), zinc (Zn) and copper (Cu) occupationally but separated from the exposure during the study. Circadian rhythms were found for plasma concentration of Pb, cadmium (Cd), Zn, Cu and chromium (Cr) in the workers. Circadian rhythms were also found for Pb, inorganic mercury (Hg), Zn and Cr in erythrocytes and for all metals except Zn in urine. Both the plasma and urinary levels of Pb, Cd, Cu and Cr together with urinary excretion of Mn and creatinine tended to decrease during night hours; both the erythrocyte and urinary levels of Hg together with both the plasma and erythrocyte levels of Zn tended to increase during morning hours. The results of profile analysis suggested that the circadian rhythm of Pb in urine was affected more strongly by its plasma and erythrocyte rhythms than by the rhythm of creatinine in urine, i.e. the rhythm of glomerular filtration; the urinary rhythms of Cd, Cr, and Mn were affected more by the creatinine rhythm; and the urinary rhythm of Cu was affected by both its plasma and creatinine rhythms. On the other hand, the urinary rhythm of Hg was assumed to be independent of the creatinine rhythm and be affected by its erythrocyte rhythm. The present study suggested that different biological limit values might be needed for different hours of the day especially for shift workers who are exposed to various heavy metals. Instead, further studies should be conducted to find the adjustment methods by which no circadian rhythms are discerned.

Role of SNAP23 in insulin-induced translocation of GLUT4 in 3T3-L1 adipocytes. Mediation of complex formation between syntaxin4 and VAMP2

Both syntaxin4 and VAMP2 are implicated in insulin regulation of glucose transporter-4 (GLUT4) trafficking in adipocytes as target (t) soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) and vesicle (v)-SNARE proteins, respectively, which mediate fusion of GLUT4-containing vesicles with the plasma membrane. Synaptosome-associated 23-kDa protein (SNAP23) is a widely expressed isoform of SNAP25, the principal t-SNARE of neuronal cells, and colocalizes with syntaxin4 in the plasma membrane of 3T3-L1 adipocytes. In the present study, two SNAP23 mutants, SNAP23-DeltaC8 (amino acids 1 to 202) and SNAP23-DeltaC49 (amino acids 1 to 161), were generated to determine whether SNAP23 is required for insulin-induced translocation of GLUT4 to the plasma membrane in 3T3-L1 adipocytes. Wild-type SNAP23 (SNAP23-WT) promoted the interaction between syntaxin4 and VAMP2 both in vitro and in vivo. Although SNAP23-DeltaC49 bound to neither syntaxin4 nor VAMP2, the SNAP23-DeltaC8 mutant bound to syntaxin4 but not to VAMP2. In addition, although SNAP23-DeltaC8 bound to syntaxin4, it did not mediate the interaction between syntaxin4 and VAMP2. Moreover, overexpression of SNAP23-DeltaC8 in 3T3-L1 adipocytes by adenovirus-mediated gene transfer inhibited insulin-induced translocation of GLUT4 but not that of GLUT1. In contrast, overexpression of neither SNAP23-WT nor SNAP23-DeltaC49 in 3T3-L1 adipocytes affected the translocation of GLUT4 or GLUT1. Together, these results demonstrate that SNAP23 contributes to insulin-dependent trafficking of GLUT4 to the plasma membrane in 3T3-L1 adipocytes by mediating the interaction between t-SNARE (syntaxin4) and v-SNARE (VAMP2).