Electrooptics of beta-FeOOH Particles in Aqueous Media

Reversing-pulse electric birefringence (RPEB) of a nearly monodisperse iron(III) hydroxide oxide sample in the beta-form (beta-FeOOH) was measured at 25 degrees C and at a wavelength of 633 nm in aqueous media in the presence of NaCl. The concentrations of beta-FeOOH and added NaCl varied between 0.00111 and 0.0555 g/L and 0.03 and 2.0 mM, respectively. Except for the suspensions with high salt concentrations, each RPEB signal showed a dip or minimum in the reverse process upon electric field reversal, together with a smooth rise in the buildup and a fall in the decay process. The observed signals were analyzed with a new RPEB theory, which takes into account not only the permanent electric dipole moment (µ) but also the root-mean-square ionic dipole moment (<m(2)>(1/2)) due to the ion fluctuation in ion atmosphere, in addition to the field-induced electronic (covalent) dipole moment Deltaalpha' E. The results showed that the slowly fluctuating moment of <m(2)>(1/2) is by far the most predominant one for the field orientation of the beta-FeOOH particle, though the permanent dipole moment µ may not be completely excluded. The rotational relaxation time of the whole particle was evaluated from the decay signal, while the relaxation time for fluctuating ions was estimated from RPEB signal fitting. The sign of the steady-state birefringence for beta-FeOOH suspensions was positive without exception under the present conditions. The birefringence signals in the steady state (delta/d) were proportional to the second power of the applied field strength (E) in the low field region; thus, the Kerr law was verified to hold for beta-FeOOH suspensions. The specific Kerr constant was evaluated for each suspension by extrapolating the values of delta/d to zero field (E-->0). Copyright 2000 Academic Press.

An analysis of the variations in potency of grayanotoxin analogs in modifying frog sodium channels of differing subtypes

Responses of tetrodotoxin-sensitive (TTX-s) and insensitive (TTX-i) Na(+) channels, in frog dorsal root ganglion (DRG) cells and frog heart Na(+) channels, to two grayanotoxin (GTX) analogs, GTX-I and alpha-dihydro-GTX-II, were examined using the patch clamp method. GTX-evoked modification occurred only when repetitive depolarizing pulses preceded a single test depolarization; modification, during the test pulse, was manifested by a decrease in peak Na(+) current accompanied by a sustained Na(+) current. GTX-evoked modification of whole-cell Na(+) currents was quantified by normalizing the conductance for sustained currents through GTX-modified Na(+) channels to that for the peak current through unmodified Na(+) channels. The dose-response relation for GTX-modified Na(+) channels was constructed by plotting the normalized slope conductance against GTX concentration. With respect to DRG TTX-i Na(+) channels, the EC(50) and maximal normalized slope conductance were estimated to be 31 microM and 0.23, respectively, for GTX-I, and 54 microM and 0.37, respectively, for alpha-dihydro-GTX-II. By contrast, TTX-s Na(+) channels in DRG cells and Na(+) channels in ventricular myocytes were found to have a much lower sensitivity to both GTX analogs. In single-channel recording on DRG cells and ventricular myocytes, Na(+) channels modified by the two GTX analogs (both at 100 microM), had similar relative conductances (range, 0.25-0.42) and open channel probabilities (range, 0.5-0.71). From these observations, we conclude that the differences in responsiveness of DRG TTX-i, and ventricular whole cell Na(+) currents to the GTX analogs studied are related to the number of Na(+) channels modified.

[Prophylactic efficacy of a basidiomycetes preparation AHCC against lethal opportunistic infections in mice]

The prophylactic effects of a Basidiomycetes preparation, AHCC, against experimental opportunistic infections were investigated in leukopenic mice. In cyclophosphamide-induced leukopenic mice, oral or intraperitoneal administration of the AHCC at doses of 1000 or 50 mg/kg/day, respectively, for 4 consecutive days prior to Candida albicans infection significantly prolonged the survival periods of the infected mice, and decreased the viable counts of C. albicans cells recovered from their kidneys. Similarly, the oral treatment with AHCC protected mice from lethal infection with Pseudomonas aeruginosa and intraperitoneal one also protected mice from infection with methicillin-resistant Staphylococcus aureus (MRSA). These results suggest a potential usefulness of the AHCC as a prophylactic agent for the management of patients with opportunistic infections.

Platelet-activating factor acetylhydrolase gene mutation in Japanese children with Escherichia coli O157-associated hemolytic uremic syndrome

Platelet-activating factor (PAF) may be involved in the pathogenesis of Escherichia coli O157-associated hemolytic uremic syndrome (HUS). PAF is degraded to inactive products by PAF acetylhydrolase. In this study, we investigated whether a PAF acetylhydrolase gene mutation (G-->T transversion at position 994) is involved in HUS in Japanese children. A point mutation in the PAF acetylhydrolase gene (G994T) was identified using polymerase chain reaction in 50 Japanese children with E coli O157-associated HUS and 100 healthy Japanese. We then determined the relationship between the PAF acetylhydrolase G994T gene mutation and clinical features of HUS. There was no difference in genotype and allele frequencies between patients with HUS and healthy controls. The mean duration of oligoanuria was significantly longer in patients with the GT genotype than in those with the GG genotype (P = 0.012). Although 11 of 15 patients (73%) heterozygous for the mutant allele (GT) required dialysis, only 13 of the 35 wild-type homozygotes (GG; 37%) required dialysis (P = 0. 030). Mean plasma PAF acetylhydrolase activity was significantly less in patients with the GT genotype than in those with the GG genotype (P < 0.0001). In conclusion, we have shown an association between the G994T PAF acetylhydrolase gene mutation and the severity of renal damage in E coli O157-associated HUS. Our study suggests that analysis of the PAF acetylhydrolase gene mutation in Japanese children with E coli O157-associated HUS may allow the prediction of the severity of HUS.

Effect of sulfhydryl reagents on the regulatory system of the L-type Ca channel in frog ventricular myocytes

The effects of sulfhydryl (SH) reagents on the L-type Ca current (ICa) were studied in frog ventricular myocytes using the whole-cell patch-clamp method. Methanethiosulfonate ethylammonium (MTSEA+) was found to enter the cell through the membrane and cause a remarkable increase in Ica from the intracellular side. Methanethiosulfonate ethyltrimethylammonium (MTSET+) and methanethiosulfonate ethylsulfonate (MTSES-) could not penetrate the membrane and were effective only when directly applied to the intracellular side. In addition, suppressive effects on ICa of these MTS reagents were indicated by the following observation. A progressive decay in the peak amplitude of ICa after establishing maximal ICa, stimulated by intracellular MTSET+, was prevented by adding extracellular dithiothreitol (DTT). The SH-oxidizing agents N-ethylmaleimide (NEM), chloramine-T (CL-T), 2,2'-dithiodipyridine (DTDP) and 2,2'-dithio-bis-5-nitropyridine (DTBNP) also exerted a stimulatory effect on Ica. The effect of SH reagents persisted even when cAMP production was inhibited with Rp-cAMP-S, or when G-protein was inhibited with 1 mM GDPbetaS, indicating that the effect is not due to cAMP production or G-protein stimulation. It is concluded that there are sites on the Ca channels that are subject to direct modification by SH reagents.

Mechanisms involved in the elevation of glutathione in RAW 264.7 cells exposed to low doses of gamma-rays

We examined the mechanisms of the elevation of glutathione level induced in macrophage-like RAW 264.7 cells by low doses of gamma-rays. The level increased soon after exposure of the cells to 50 cGy of gamma-rays, peaked between 3 hours and 6 hours and returned almost to the time 0 value by 24 hours post-irradiation. Doses between 25 and 100 cGy significantly increased the glutathione level at 4 hours post-irradiation. However, there was no significant elevation at doses of more than 100 cGy or less than 25 cGy. When the effect of dose rate was examined at a constant absorbed dose of 50 cGy, dose rates of more than 50 cGy/minute significantly increased the GSH level at 4 hours post-irradiation. It was also shown that the elevation of glutathione level in cells irradiated with low doses of gamma-rays followed the induction of mRNA coding for gamma-glutamylcysteine synthetase (gamma-GCS), a rate-limiting enzyme of the de novo glutathione synthesis pathway. When the cells were exposed to the radiation in the presence of genistein, calphostin C or nifedipine, the elevations of glutathione and gamma-GCS mRNA expression were both mostly blocked. EGTA also strongly inhibited these elevations. These results suggest that the tyrosine kinase, calcium channel and protein kinase C activities play an essential role in the low-dose-radiation-induced elevation of cellular glutathione.

Pulsed Electric Linear Dichroism of Triphenylmethane Dyes Adsorbed on Montmorillonite K10 in Aqueous Media

Electric linear dichroism (ELD) spectra of two cationic triphenylmethane dyes, crystal violet (CV) and malachite green (MG), bound to sodium montmorillonite K10 (MK-10) were studied at 20 degrees C in aqueous media at two mixing ratios, D/S, of 0.10 and 0.24 in the 700- to 400-nm wavelength region and in the applied electric field strength range between 0 and 3 kV/cm. The specific parallel and perpendicular dichroism (Delta A( ||)/A and Delta A( perpendicular)/A) spectra of dye-adsorbed MK-10 suspension were measured at a fixed field strength with an apparatus equipped with a 512-channel photodiode array detector. By changing the field strength over a wide range, a series of the reduced dichroism values of the bound dyes were measured at a fixed wavelength. By fitting these dichroism values to theoretical orientation functions, the intrinsic reduced dichroism (Delta A/A)(int) spectra at the limiting high fields (ELD spectrum) were determined for CV and MG bound to MK-10. No appreciable difference was observed at the two D/S values. The ELD spectra of these bound dyes are undulatory but never constant, throughout their absorption region; thus, the dye plane does not lie flatly either on the surface or between layers of MK-10 particle. The isotropic absorption spectra, A, of bound CV and MG were each deconvoluted to eight partial absorption bands, which were grouped into three differently polarized transitions, i.e., one out-of-plane and two mutually perpendicular in-plane. The optical transition dipole moment direction of each group was found to make a considerable angle with respect to the symmetry axis of the disklike MK-10 particle, whose plane (or surface) tends to orient toward the applied electric field at the limiting high fields. By simulating the observed ELD spectra of bound CV and MG with those deconvoluted bands, the roll, tilt, and inclination angles of both dyes were evaluated quantitatively with a new analytical method. The average angles (+/-&theta;(R), +/- &theta;(T), |&theta;(N)|) are -(34-47) degrees, 34 degrees, and 51 degrees for bound CV and -44 degrees, 32 degrees, and 53 degrees for bound MG at two D/S values; thus, the triangular plane of each dye is rolled as well as tilted with a large inclination angle. Copyright 2000 Academic Press.

Expression of gap junction protein connexin 32 in chronic liver diseases

BACKGROUND

Gap junctions contain intercellular channels through which contacting cells communicate directly. The expression of connexin 32, a major gap junction protein in the liver, during the progression of chronic liver diseases has not yet been clarified.

METHODS

Immunohistochemical staining was performed using anti-connexin 32 antibody on 6 specimens of normal human liver, 7 of chronic viral hepatitis, and 7 of liver cirrhosis.

RESULTS

The number of gap junction plaques in chronic viral hepatitis and liver cirrhosis was significantly smaller than that in normal liver (10350+/-2180 and 7550+/-3040 vs 22560+/-3700 spots/mm2, p<0.01). The number of gap junction plaques tended to be lower in liver cirrhosis than in chronic viral hepatitis.

CONCLUSION

These results suggest that in chronic liver diseases impaired intercellular communication between hepatocytes occurs.

Expression of galectin-1 mRNA correlates with the malignant potential of human gliomas and expression of antisense galectin-1 inhibits the growth of 9 glioma cells

Although its precise function has not yet been established, galectin-1 seems to play a role in tumor progression. In this study, we investigated galectin-1 mRNA expression in human glioma specimens and glioma cell lines. Northern blot analysis showed higher galectin-1 mRNA levels in glioma tissues. The 0.7-kb galectin-1 mRNA transcript was detected, and the expression level correlated with the malignant state, from low-grade astrocytoma to glioblastoma. In several human glioma specimens, immunohistochemical examination with antiserum against a synthetic peptide corresponding to the predicted C-terminal sequence of the protein showed high levels of galectin-1 expression. To clarify the correlation between the expression of galectin-1 and the malignancy of gliomas, we examined whether expression of antisense galectin-1 would suppress tumor growth in rat 9L cells that express high levels of galectin-1. The cells were transfected with a plasmid DNA that produces antisense galectin-1 mRNA under the control of the metallothionein promoter, and stable clones expressing low levels of galectin-1 protein in comparison with control clones were isolated. Cells with low levels of galectin-1 displayed dramatic phenotypic changes in their morphology and growth properties compared with vector-transfected control 9L cells. Our data suggest that decreased expression of galectin-1 may arrest the growth of rat 9L cells.

Inhibitory effects of post low dose gamma-ray irradiation on ferric-nitrilotriacetate-induced mice liver damage

We studied the effects of a single post whole-body low-dose irradiation (50 cGy of gamma-ray) on mice with ferric nitrilotriacetate (Fe3+-NTA)-induced transient hepatopathy. As a result, low-dose irradiation accelerated the rate of recovery. Based on the changes in glutamic oxaloacetic transaminase (GOT) activities, glutamic pyruvic transaminase (GPT) activities and lipid peroxide levels, it was shown that hepatopathy was improved by low-dose irradiation 3 h after Fe3+-NTA administration. This may be because of the enhancement of antioxidant agents such as total glutathione (GSH + GSSG), glutathione peroxidase (GPX), glutathione reductase (GR) and gamma-glutamylcysteine synthetase (gamma-GCS) by low-dose irradiation. These findings suggest that low-dose irradiation relieved functional disorders at least in the livers of mice with active oxygen species related diseases.

[Validity and reproducibility of a semi-quantitative food frequency questionnaire for nutritional education of patients of diabetes mellitus (FFQW65)]

BACKGROUND

A self-administered semi-quantitative food frequency questionnaire with 65 food lists (FFQW65) was developed for the nutritional education of patients of diabetes mellitus.

METHODS

Relative validity and reproducibility of nutrient intakes as assessed by FFQW65 were investigated in volunteers of 71 males. To assess the relative validity, a one-week diet record was used as a reference. The FFQW65 was administered twice at an interval of 10 month in order to assess the reproducibility. Log transformed data was used to obtain Pearson correlation coefficients.

RESULTS

As for the validity, Pearson correlation coefficient of total energy intake of breakfast was 0.74 and the relative difference between predicted value and diet record was relatively small (the difference was -5 kcal and relative difference rate was 1.1%). Compared with breakfast, those for lunch, supper and one-day total energy intakes were relatively lower (0.52, 0.66 and 0.64, respectively) and the relative differences were around 10%, respectively. The one-day intakes of sixteen nutrients (except for potassium and niacin) ranged from 0.28 to 0.64. Energy adjusted correlation coefficients for protein, iron and cholesterol were low (0.16, 0.14 and 0.19, respectively). Those for the other thirteen nutrients ranged from 0.26 to 0.65. As for the reproducibility, the second survey using FFQW65 was administered to 64 males. Pearson correlation coefficient of one-day total energy intake was 0.76 and those for the other nutrients ranged from 0.54 (vitamin D) to 0.81 (calcium).

CONCLUSION

The results suggest that FFQW65 can be used for the evaluation of energy intake by usual meals for nutrition education of patients of diabetes mellitus.

On site of action of grayanotoxin in domain 4 segment 6 of rat skeletal muscle sodium channel

Grayanotoxin I (GTX I) is a diterpenoid extracted from the family of Ericaceae that binds to Na(+) channels and causes persistent activation. We investigated the interaction of GTX I with the amino acid residues I1575, F1579 and Y1586 in transmembrane segment D4S6 of micro1. In F1579A, GTX shifted the threshold potential about 50 mV in the hyperpolarizing direction and modified Na(+) channels twice as efficiently as that in wild-type. In contrast, these GTX-effects were eliminated completely in the I1575A mutant and were reduced substantially in mutant Y1586A. Lysine substitution for F1579 significantly reduced and for Y1586 completely eradicated the GTX-effect. Our data suggest that the GTX receptor site shares overlapping but non-identical molecular determinants with BTX in D4S6 and has common molecular determinants in D1S6.

Dose-dependency in local disposition of 5-fluorouracil under non-steady-state condition in rat liver

Dose-dependency in local disposition of 5-fluorouracil (5-FU) was evaluated using the rat liver in the once-through perfusion system under the non-steady-state condition. A curve-fitting program based on Finite Element Method, MULTI(FEM), was adopted to evaluate the capacity-limited elimination in the hepatic local disposition of 5-FU, which is described by a nonlinear dispersion model with a pulse input. The dose of 5-FU was increased from 10.4 to 208 microg for rat livers at five dose levels. Two nonlinear models, two-compartment dispersion models with Michaelis-Menten elimination from the central compartment or from the peripheral compartment, were employed for comparison. The hepatic recovery ratio, F(H), increased from 13.1% to 68.3% and the mean transit time, t(H), increased from 5.1 to 13.1 s with an increase in the dose. It was found that the hepatic local disposition of 5-FU was well represented by the peripheral elimination model. V(max) and K(m) in the model with peripheral Michaelis-Menten elimination were estimated to be 9.04 mg/h and 2.88 mg/L, respectively. V(max) estimated by the present investigation in situ was about seven times greater than that in vitro, whereas K(m) in situ was close to that in vitro. This result suggests that the elimination activity by the hepatocytes in vitro may be lowered, compared with that in situ.

Differential effects of interleukin-4 and interleukin-10 on nitric oxide production by murine macrophages

OBJECTIVE

To study the effect of interleukin (IL)-4 and IL-10 on nitric oxide (NO) production by macrophages.

MATERIALS AND METHODS

Elicited or resident peritoneal macrophages (PMO) and a macrophage cell line Raw264.7 were primed by IL-4 or IL-10 for 6 hours, and were further incubated in the presence of interferon (IFN)-gamma and/or lipopolysaccharide (LPS) for 48 hours. NO2- accumulation in the supernatant of cultured cells was used as an indicator of NO production and was determined by the standard Griess reaction adapted for microplates. The amount of tumor necrosis factor (TNF)-alpha in the culture supernatants was determined with a commercially available ELISA kit. The absorbance was measured at 450 nm with a microplate photometer.

RESULTS

IL-4 inhibited NO production by murine macrophages of different sources and the macrophage cell line Raw264.7. In contrast, different macrophage populations showed differential responses to IL-10. After stimulation with LPS or IFN-gamma, IL-10 suppressed NO production by elicited PMO but enhanced NO production by resident PMO or by Raw264.7. Both IL-4 and IL-10 inhibited the production of TNF-alpha, which has been shown to play a crucial role in NO production. In the presence or the absence of blocking antibody to TNF-alpha, IL-10 always enhanced NO production by resident PMO. This result suggests that the inhibition of TNF-alpha production and the enhancement of NO production by resident PMO stimulated with IL-10 are independent, coexisting events.

CONCLUSIONS

Factors other than TNF-alpha have been suspected to influence NO production by macrophages, and this study indicates that IL-10 may be a candidate cytokine for resident PMO.

Low-dose gamma-ray irradiation reduces oxidative damage induced by CCl4 in mouse liver

We examined the effects of irradiation (50 cGy of gamma-ray) reducing the oxidative damage in carbon tetrachloride (CCl4)-hepatopathy mice. We made pathological examinations and analyzed transaminase activity (glutamic oxaloacetic transaminase and glutamic pyruvic transaminase), lipid peroxide level and the activities of endogenous antioxidants in the mouse. The irradiation was found to accelerate the recovery. Based on pathological examination as well as changes in each transaminase activity and lipid peroxide levels, it was shown that hepatopathy improved 3 d after the irradiation. The activities of glutathione reductase and glutathione peroxidase rapidly elevated after irradiation, and the total glutathione content gradually increased in the irradiation group. Both activities of gamma-glutamylcysteine synthetase and catalase were higher than normal at all times after the irradiation and gradually increased. In addition, the gamma-glutamylcysteine synthetase activity changed in a similar fashion to the total glutathione content. However, superoxide dismutase activity in both groups decreased and that of the irradiation group was significantly lower than that of the sham-irradiation group. These findings suggest that low-dose radiation relieved functional disorder at least in the liver of mice with active oxygen diseases.

Polymorphisms within the interleukin-10 receptor cDNA gene (IL10R) in Japanese patients with systemic lupus erythematosus

OBJECTIVE

To assess the association between polymorphisms within the interleukin-10 receptor cDNA gene (IL10R) and systemic erythematosus (SLE) in Japanese people.

METHOD

We examined the IL-10 receptor genotype of 109 SLE patients and 102 healthy subjects by the reverse transcription-polymerase chain reaction-restriction fragment length polymorphism (RT-PCR-RFLP) method.

RESULTS

There was no difference in the IL10R genotype frequencies of these two groups.

CONCLUSION

The IL10R genotype does not determine susceptibility to SLE in Japanese people.

Chemical characterisation of six oligosaccharides in a sample of colostrum of the brown capuchin, Cebus apella (Cebidae: primates)

Carbohydrates were extracted from a sample of brown capuchin colostrum and six of the component oligosaccharides were separated and purified by gel filtration and preparative thin layer chromatography. Their structures were determined by 1H-NMR to be as follows: Gal beta 1-->4[Fuc alpha 1-->3]Glc (3-fucosyllactose) Gal beta 1-->3Gal beta 1-->4Glc (beta-3'-galactosyllactose) Gal beta 1-->6Gal beta1-->4Glc (beta-6'-galactosyllactose) Gal beta-->3[Gal beta 1-->4GlcNAc beta 1-->6]Gal beta 1-->4Glc (lacto-N-novopentaose I) Gal beta 1-->4GlcNAc beta 1-->3[Gal beta 1-->4GlcNAc beta 1-->6]Gal beta 1-->4Glc (lacto-N-neohexaose) Neu5Ac alpha 2-->3Gal beta 1-->4Glc (3'-N-acetylneuraminyllactose) Of these, all except lacto-N-novopentaose I have been previously found in human milk or colostrum.

Elevation of glutathione in RAW 264.7 cells by low-dose gamma-ray irradiation and its responsibility for the appearance of radioresistance

We examined the relationship between the induction of glutathione (GSH) level in macrophage-like RAW 264.7 cells by a low (adapting) dose gamma-rays and the cell damage caused by a lethal dose of gamma-rays at various intervals after the adapting dose. The reduced glutathione (GSH) level increased soon after exposure of the cells to 25 cGy of gamma-rays, peaked between 3 hr and 6 hr, and returned almost to the zero time (0 hr) level by 24 hr post-irradiation. Cell damage was assessed by measuring the 3H-thymidine (3H-TdR) incorporation into cellular DNA. gamma-Ray irradiation produced a dose-dependent cell damage in RAW cells, causing about 40% and 60% inhibition of 3H-TdR incorporation into DNA at 1.0 Gy and 2.0 Gy, respectively, as compared with non-irradiated cells. Treatment with the adapting dose of 25 cGy at 1 hr or 24 hr before the lethal irradiation was ineffective. However, pre-irradiation with 25 cGy at 3 hr or 6 hr prior to lethal irradiation inhibited the decrease of 3H-TdR incorporation into DNA, indicating a protective effect. GSH exogenously added to the medium also inhibited the cell damage induced by lethal doses of gamma-Rays in a dose-dependent manner. These results indicate that the induction of endogenous GSH in living cells immediately following low-dose gamma-Ray irradiation is at least partially responsible for the appearance of radioresistance to a subsequent lethal dose of radiation, and may make it possible to use higher doses of radiation in radiotherapy for tumor patients.

Changes of SOD-like substances in mouse organs after low-dose X-ray irradiation

We demonstrated that low-dose irradiation with 50 cGy of X-ray induces in vivo production of superoxide dismutase (SOD)-like substances and accelerates antioxidant activity. To elucidate the defense mechanism against X-ray radiation, we examined which components among these SOD-like substances, such as SOD, vitamin C and celuroplasmin, are produced by low-dose irradiation. Our study revealed that SOD-like specific activity hardly involved SOD-like substances other than SOD. Moreover, it is suggested that low-dose irradiation induced synthesis and production of SOD itself, leading to elevation of SOD-specific activity.

Point-mutations related to the loss of batrachotoxin binding abolish the grayanotoxin effect in Na(+) channel isoforms

The effect of grayanotoxin (GTX) on site-specific mutants of the alpha-subunit of rat skeletal muscle Na(+) channels (micro1) (micro1-I433K, micro1-N434K and micro1-L437K), which are resistant to batrachotoxin (BTX) (Wang and Wang (1998) Proc Natl Acad Sci USA, 95, 2653-2658) was studied using a whole-cell patch-clamp method. The GTX modification of the Na(+) channels was detected as a characteristic-sustained Na(+) current flow with repetitive pulses. We also studied the GTX action on mutants of the alpha-subunit of rat heart Na(+) channels (RH1) (RH1-V406K and RH1-L410K) which match with micro1-I433 and micro1-L437. All the mutants lost their sensitivity to GTX. This finding indicates that GTX may share a binding site with BTX in transmembrane segment I-S6 of two different Na(+) channel isoforms, micro1 and RH1.

[Validity of urinary glucose test for diabetes screening in workplace regular medical checkups]

It has been acknowledged that urinary glucose level varies depending on the time after meal which may hence affect validity of urinary glucose test as a screening test for diabetes. However, sample collection time has not been standardized for urinary glucose test in workplace regular medical checkups. In this study, we investigated the effect of timing of urine sampling on results of urinary glucose screening tests, and using data obtained from the 75 g oral glucose tolerance tests (OGTT) evaluated the validity of urinary glucose test in workplace medical checkups. Also, we made a survey among industrial physicians about the timing of sample collection. Between 1991 and 1996, 455 males and 116 females who participated in a 2-day health examination including the OGTT in a hospital in Chiba were used as study subjects. These did not include an additional 22 subjects who had already been diagnosed as having diabetes but received the OGTT. The examinees observed a strict fast after supper the previous evening and urine and blood samples were collected before and 2 hours after glucose intake for the OGTT. Diagnosis of diabetes was made following the criteria of WHO (1985) and screening test results were defined positive when urinary glucose level was equal to or more than 40 mg/dl. Sensitivity and specificity were calculated for diabetes and impaired glucose tolerance separately for male and female. Industrial physicians who participated in a lecture course for qualification were surveyed about the timing of urine sample collection for urinary glucose test in workplace regular medical checkups. For the urine samples collected 2 hours after glucose intake, sensitivity was very high (male 84%, female 100%), in addition to a relatively high specificity (male 71%, female 92%). However the samples collected before glucose intake showed extremely poor sensitivity (male 11%, female 0%). Similar results were obtained when screening was made for impaired glucose tolerance and both diabetes and impaired glucose tolerance combined. The survey among the industrial physician revealed that in the majority (58%) of workplace medical checkups, the urine sample had been collected when examinees were fasting. The largest reason for this was that the urinary glucose test was performed together with upper gastro-intestinal examination or measurement of serum triglyceride both of which require fasting of examinees. The results of the present study showed that urinary glucose tests have been frequently performed at a timing that produces low validity. The procedures of workplace regular medical checkups should be evaluated with the concept of Evidence Based Medicine. The standard of the timing of urine sample collection for urinary glucose test should be carefully examined.

The electric dipole moment of DNA-binding HU protein calculated by the use of an NMR database

Electric birefringence measurements indicated the presence of a large permanent dipole moment in HU protein-DNA complex. In order to substantiate this observation, numerical computation of the dipole moment of HU protein homodimer was carried out by using NMR protein databases. The dipole moments of globular proteins have hitherto been calculated with X-ray databases and NMR data have never been used before. The advantages of NMR databases are: (a) NMR data are obtained, unlike X-ray databases, using protein solutions. Accordingly, this method eliminates the bothersome question as to the possible alteration of the protein structure due to the transition from the crystalline state to the solution state. This question is particularly important for proteins such as HU protein which has some degree of internal flexibility; (b) the three-dimensional coordinates of hydrogen atoms in protein molecules can be determined with a sufficient resolution and this enables the N-H as well as C = O bond moments to be calculated. Since the NMR database of HU protein from Bacillus stearothermophilus consists of 25 models, the surface charge as well as the core dipole moments were computed for each of these structures. The results of these calculations show that the net permanent dipole moments of HU protein homodimer is approximately 500-530 D (1 D = 3.33 x 10(-30) Cm) at pH 7.5 and 600-630 D at the isoelectric point (pH 10.5). These permanent dipole moments are unusually large for a small protein of the size of 19.5 kDa. Nevertheless, the result of numerical calculations is compatible with the electro-optical observation, confirming a very large dipole moment in this protein.

Th1/Th2 balance of peripheral T helper cells in systemic lupus erythematosus

OBJECTIVE

To analyze the Th1/Th2 balance of peripheral Th cells in patients with systemic lupus erythematosus (SLE).

METHODS

The Th1:Th2 ratio was analyzed in 3 groups: SLE without proteinuria (group I; n = 23), SLE with proteinuria (group II; n = 31), and normal controls (group III; n = 24). Group II patients who had undergone renal biopsy were classified into 3 subgroups based on their renal histopathologic findings. The intracellular cytokine detection method with flow cytometry was used to quantitate Th1 and Th2 cells.

RESULTS

There was no difference in the mean Th1:Th2 ratio between SLE patients (groups I and II) and healthy controls (group III). However, the mean value in group II was significantly higher than those in groups I and III. Moreover, within group II, the mean value in SLE patients who had diffuse proliferative lupus nephritis (World Health Organization class IV) was especially high.

CONCLUSION

Although SLE has been considered to be a disease in which Th2 cells predominate, the Th1/Th2 balance of peripheral Th cells in SLE patients in the present study did not show a predominance of these cells. In contrast, among SLE patients with WHO class IV lupus nephritis, there was a strong predominance of Th1.