Infection of replication-deficient adenoviral vector enhances interleukin-8 production in small airway epithelial cells more than in large airway epithelial cells

OBJECTIVE

In clinical trials or experiments of gene therapy, airway administration of an adenoviral-based vector (E1A-deleted) elicits a dose-dependent inflammatory response with limitation in the duration of transgene expression. The purpose of this study was to evaluate the possibility that the adenoviral-based vector directly enhances IL-8 production independent of adenoviral E1A in normal human airway epithelial cells and to examine the different responses between primary human bronchial epithelial cells (HBE) and primary human small airway epithelial cells (HSAE) in production of IL-8 following exposure to an adenovirus vector.

METHODOLOGY

Interleukin (IL)-8 levels were evaluated in the culture medium from HBE and HSAE treated with increasing doses of E1A-deleted adenoviral vector contained the Escherichia coli LacZ reporter gene (AdCMVLacZ). To clarify the mechanism of enhancing IL-8 production in airway epithelial cells by infection with adenovirus vector, alphavbeta5 agonistic antibody as an analogue of adenoviral capsid and adenoviral capsid vector denatured by exposure to ultraviolet (UV) light were used in the present study.

RESULTS

Inoculation of HBE with AdCMVLacZ at a multiplicity of infection (MOI) of between 1 and 200 resulted in a dose-dependent expression of LacZ, and maximal expression was observed at a MOI of 100. In contrast, inoculation of HSAE with AdCMVLacZ resulted in maximum expression of LacZ at a MOI of 10. Interleukin-8 levels in culture media from the same experiments revealed significantly greater production of IL-8 in HSAE inoculated with AdCMVLacZ at a MOI of 50, compared to HBE under the same conditions. The capsid-denatured adenoviral vector did not enhance IL-8 production, and alphavbeta5 agonistic antibody induced IL-8 enhancement.

CONCLUSION

These results suggest that the adenoviral vector directly induces the expression of airway epithelial inflammatory cytokines in the pathogenesis of inflammation and that small airway cells have a greater affinity for adenovirus than other airway epithelial cells.

[Effect of ATP-sensitive K+ channel blocker (quinine) on the dopamine decrease induced by selective D3 agonist (7-OH-DPAT) in the rat striatum]

In vivo brain microdialysis was used to investigate the role of D3 receptors relating to dopamine auto-regulated systems in the rat. A local infusion of the dopamine D3 selective agonist, 7-OH-DPAT (100 nM), into the striatum through the dialysis membrane produced a significant decrease in extracellular concentrations of dopamine. A local application of ATP-sensitive K+ (KATP) channel blocker, quinine (10 microM, 100 microM, 1 mM), produced dose-dependent increases in extracellular concentrations of dopamine. Quinine (100 microM, 1 mM) significantly blocked a 7-OH-DPAT-induced decrease in the striatal dopamine levels in the dose-dependent manner. Because of many previous reports, the autoregulated functions of dopamine release by D3 receptors in the striatum can be regarded mainly as nerve terminal autoreceptors and/or a short-loop negative feedback system. Therefore these results suggest that KATP channels may be present in nigrostriatal dopaminergic terminals and that in the striatum, presynaptic dopamine D3 autoreceptors and/or a post-synaptic D3 related short-loop negative feedback system inhibit dopamine release tonically by the activation of KATP channels.

The N-terminal domain of the yeast permease Bap2p plays a role in its degradation

The amino acid permease Bap2p in Saccharomyces cerevisiae mediates a major part of the uptake of leucine, isoleucine, and valine from media containing a preferred nitrogen source. Although the transcriptional controls of BAP2 have been well studied, the posttranslational down-regulation mechanisms for Bap2p have not been established. Here we show that Bap2p is subject to a starvation-induced degradation upon rapamycin treatment or cultivation with proline as the sole nitrogen source. The starvation-induced degradation of Bap2p was dependent on the cellular functions of ubiquitination and endocytosis. Down-regulation of the permease required the most probable ubiquitination sites, the lysine residues situated in the N-terminal 49 residues, as well as the C-terminal domain. Furthermore, when the N-terminal domain of Bap2p was fused to the general amino acid permease Gap1p, the resultant chimeric permease became susceptible to the starvation-induced degradation, indicating that the Bap2p N-terminus contains a determinant responsive to the starvation signals.

Butylhydroxytoluene (BHT) increases susceptibility of transgenic rasH2 mice to lung carcinogenesis

PURPOSE

Transgenic mice carrying the human prototype c-Ha-ras gene (rasH2 mice) are highly susceptible to lung carcinogens. In order to investigate the possibility of developing a rapid in vivo assay for lung carcinogens, we examined whether the tumor-promoting activity of butylhydroxytoluene (BHT) is efficacious in rasH2 mice.

METHODS

rasH2 mice and wild littermates of both genders were pre-treated with carcinogens [urethane (UR), 4-nitroquinoline 1-oxide (4NQO) or diethylnitrosamine (DEN)], and, one day later, given a 400 mg/kg dose of BHT.

RESULTS

Six weeks after the initiation treatment, evidence of carcinogenicity could be detected in male and female rasH2 mice that had received UR doses of > or = 250 mg/kg and > or = 125 mg/kg, respectively, prior to exposure to BHT, whereas only 500 mg/kg of UR was sufficient to induce tumors in female rasH2 mice given the carcinogen alone. The carcinogenicity of 15 mg/kg of 4NQO could be detected after 9 weeks in male rasH2 mice given the carcinogen followed by BHT. Similarly, the carcinogenicity of 60 mg/kg of DEN could be detected after 9 weeks and 6 weeks, respectively, in male and female rasH2 mice given the carcinogen followed by BHT. No carcinogenicity could be demonstrated through the experimental period with doses of 4NQO or DEN given alone.

CONCLUSIONS

These results indicate that BHT administration increases the susceptibility of rasH2 mice to lung carcinogens, and suggest that the use of BHT in rasH2 mice might lead to the establishment of a rapid in vivo assay for lung carcinogens.

Stable chromosome aberrations in atomic bomb survivors: results from 25 years of investigation

Frequencies of stable chromosome aberrations from more than 3,000 atomic bomb survivors were used to examine the nature of the radiation dose response. The end point was the proportion of cells with at least one translocation or inversion detected in Giemsa-stained cultures of approximately 100 lymphocytes per person. The statistical methods allow for both imprecision of individual dose estimates and extra-binomial variation. A highly significant and nonlinear dose response was seen. The shape of the dose response was concave upward for doses below 1.5 Sv but exhibited some leveling off at higher doses. This curvature was similar for the two cities, with a crossover dose (i.e. the ratio of the linear coefficient to the quadratic coefficient) of 1.7 Sv (95% CI 0.9, 4). The low-dose slopes for the two cities differed significantly: 6.6% per Sv (95% CI 5.5, 8.4) in Hiroshima and 3.7% (95% CI 2.6, 4.9) in Nagasaki. This difference was reduced considerably, but not eliminated, when the comparison was limited to people who were exposed in houses or tenements. Nagasaki survivors exposed in factories, as well as people in either city who were outside with little or no shielding, had a lower dose response than those exposed in houses. This suggests that doses for Nagasaki factory worker survivors may be overestimated by the DS86, apparently by about 60%. Even though factory workers constitute about 20% of Nagasaki survivors with dose estimates in the range of 0.5 to 2 Sv, calculations indicate that the dosimetry problems for these people have little impact on cancer risk estimates for Nagasaki.

Expression of multidrug resistance protein and messenger RNA correlate with (99m)Tc-MIBI imaging in patients with lung cancer

In vitro studies have shown that (99m)Tc-sestamibi (MIBI) is a transport substrate for the P-glycoprotein (Pgp) pump and the multidrug resistance-associated protein (MRP) pump. However, whether MRP and lung resistance protein (LRP) affect tumor accumulation and efflux of (99m)Tc-MIBI in lung cancer is not known. In this study, we explored whether Pgp and the other pumps, MRP and LRP, affect tumor accumulation and efflux of (99m)Tc-MIBI in lung cancer.

METHODS

Thirty-four lung cancer patients who underwent surgery were examined. Before surgery, (99m)Tc-MIBI SPECT was performed 15 min and 180 min after injection, and early uptake, delayed uptake (L/Nd), and washout rate (L/Nwr) of (99m)Tc-MIBI were obtained. Pgp, MRP, and LRP expression were investigated by immunohistochemistry. The messenger RNA (mRNA) level of Pgp, MRP, and LRP was determined by real-time reverse-transcription polymerase chain reaction. The lung cancer (99m)Tc-MIBI images were correlated with protein and mRNA expression.

RESULTS

The mean L/Nd of the Pgp (-) group was significantly higher than that of the Pgp (++) group (P = 0.0324). The Pgp (++) group had a higher L/Nwr than did the Pgp (-) group (P = 0.0269). The mean L/Nd of the Pgp mRNA low-expression group was significantly higher than that of the Pgp mRNA high-expression group (P = 0.0127). The Pgp mRNA high-expression group had a higher L/Nwr than did the Pgp mRNA low-expression group (P = 0.0825). No appreciable correlation was found between the lung cancer (99m)Tc-MIBI images and the expression of MRP or LRP on the level of protein or mRNA.

CONCLUSION

These data suggest that an increased level of Pgp expression correlates with a low accumulation on delayed scans and a high L/Nwr of (99m)Tc-MIBI in lung cancer. Neither MRP nor LRP expression on the level of either protein or mRNA correlated significantly with tumor accumulation or efflux of (99m)Tc-MIBI in lung cancer.

[Evaluation of spontaneous pneumothorax in patients with pulmonary lymphangioleiomyomatosis]

We retrospectively evaluated the development of spontaneous pneumothorax in patients with pulmonary lymphangioleiomyomatosis (LAM). Fifteen patients with LAM, whose diagnosis was confirmed histopathologically, were enrolled. All were women, and had a mean age at diagnosis of 31.6 +/- 7.3 years. They were divided into two groups according to the presence or absence of pneumothorax at the time of onset, Group A consisting of nine patients with pneumothorax, and Group B, of six without pneumothorax. Spontaneous pneumothorax developed in 15 out of a total of 18 hemithoraces in Group A patients in whom 13 hemithoraces were surgically treated for pneumothorax (eight open thoracotomies and five video-assisted thoracoscopic surgeries). Bullectomy with either parietal pleurectomy, pleural abrasion, or instillation of chemical irritants to prevent the recurrence of pneumothorax offered better outcomes than bullectomy alone in terms of the postoperative recurrence rate of pneumothorax (p < 0.05). On the other hand, three of the five Group B cases developed pneumothorax during the course of LAM, but none was operated because of severely impaired lung function. The other patient in Group B was not only free of pneumothorax at onset, but also did not develop pneumothorax or suffer from impaired lung function. There were no deaths due to pneumothorax recorded among Group A patients, but two patients in group B died. A better survival rate was noted in Group A than in Group B by Kaplan-Meier analysis, suggesting that these two groups may represent the broad clinical spectrum of LAM.

Detection of stable chromosome aberrations by FISH in A-bomb survivors: comparison with previous solid Giemsa staining data on the same 230 individuals

PURPOSE

To evaluate the relative abilities of the solid Giemsa staining (conventional) and fluorescence in situ hybridization (FISH) methods in the detection of stable chromosome aberrations in the peripheral blood lymphocytes of A-bomb survivors.

MATERIALS AND METHODS

Lymphocytes from a total of 230 A-bomb survivors for whom prior chromosome aberration data had been obtained by the conventional method were recently examined afresh using FISH in which chromosomes 1, 2 and 4 were painted with composite probes.

RESULTS

It was found that the early use of the solid Giemsa staining method had allowed the detection of translocations with a mean frequency of 73% of the value for the genome-equivalent translocation frequency (F(G)) that was now obtained using FISH. The disparity may at least in part be due to the reciprocal exchange of seemingly identical amount of chromosome material; such exchanges can escape detection by the conventional method but can be readily identified using FISH.

CONCLUSION

It has previously been established that the conventional method can detect about 20% of radiation-induced translocations as abnormal monocentric chromosomes. Present results indicate that an additional 50% can be detected if proper karyotyping is conducted and the remaining 30% are not likely to be detected unless FISH or banding methods are used. Thus, solid Giemsa staining accompanied by karyotyping may not be quite as unsuitable as is generally assumed for retrospective biodosimetry analyses, which deal mainly with stable aberrations.

Chromosome aberration analysis in persons exposed to low-level radiation from the JCO criticality accident in Tokai-mura

Chromosome aberrations were studied in peripheral blood lymphocytes of 43 persons who were exposed to low-level radiation of mixed neutrons and gamma-rays resulting from the JCO criticality accident. When the age-adjusted frequencies of dicentric and ring chromosomes were compared with the dose calibration curve established in vitro for 60Co gamma-rays as a reference radiation, a significant correlation was observed between the chromosomally estimated doses and the documented doses evaluated by physical means. The regression coefficient of the chromosomal doses against the documented doses, 1.47 +/- 0.33, indicates that the relative biological effectiveness of fission neutrons at low doses is considerably higher than that currently adopted in the radiation protection standard.

Infrastructure of pharmaceutical research and development in Japan

OBJECTIVE

To examine the roles of different types of hospitals in implementation of multicenter Phase II/III trials in Japan, specifically focusing on two dichotomies: public versus private, and academic versus nonacademic. Possible explanation was sought as to why a hospital of one category was more likely to participate in specific types of trials in the Japanese medical environment.

METHODS

A database containing attributes of published clinical trials (n = 217) was established from four journals featuring reports of clinical trial results. The preferences of public and academic hospitals for specific types of trials were estimated by applying a linear regression model. The trial compositions of these institutions were also estimated, taking the actual prevalence of trials in 1995 into consideration.

RESULTS

Public sector hospitals, which were established for particular policy purposes in the national healthcare system, were more likely to accept trials in some fields (e.g., cardiovascular diseases, anesthesiology, antineoplastics, pediatrics) and of some kinds (e.g., Phase II rather than Phase III trials, trials supervised by the principal investigator in the public sector). Academic hospitals also showed preferences for some types of trials (e.g., cardiovascular diseases, dermatology; Phase II rather than Phase III trials). The analysis focusing on public hospitals suggested that policy purposes were achieved at least in some fields such as antineoplastics and anesthesiology.

CONCLUSIONS

Japanese clinical trials were unevenly distributed between public and private sectors, and also between academic and nonacademic sectors. These data provide fundamental information about the clinical research environment for future pharmaceutical research and development strategies and policies.

Genetic loci controlling susceptibility to gamma-ray-induced thymic lymphoma

BALB/c is a susceptible strain for the development of gamma-ray induced mouse thymic lymphoma whereas MSM shows resistance. Association analysis of 220 backcross mice between the two strains using 67 markers was carried out to identify loci involved in the control of susceptibility. The genotype of mice with lymphoma showed excess heterozygosity relative to MSM homozygosity at D2Mit15 and D4Mit12 and was skewed toward MSM-derived alleles at D5Mit5. The P values in Mantel-Cox test were 0.0048 (D2Mit15), 0.0034 (D4Mit12) and 0.0048 (D5Mit5), suggesting association at the three loci in the susceptibility. Cooperative effect on lymphomagenesis was also observed among the three loci. To obtain independent evidence for linkage at D4Mit12, we made partially congenic mice in which a D4Mit12 region in BALB/c was replaced by MSM-derived homolog. Examination for the lymphoma susceptibility in 78 progeny of the congenic mice confirmed the effect of the locus near D4Mit12 (P=0.0037). The result, together with the linkage analysis, shows that the locus near D4Mit12 is regarded as a confirmed linkage but the other two loci as marginally suggestive.

Fructose- 1,6-bisphosphate did not affect hippocampal neuronal damage caused by 10 min of complete umbilical cord occlusion in fetal sheep

Fructose-1, 6-bisphosphate (FBP) has a neuroprotective effect in neonatal and adult rats. The purpose of this study was to examine the effects of FBP on hippocampal neuronal damage in fetal sheep asphyxiated by 10 min of complete umbilical cord occlusion. Thirteen fetal sheep at 124 days of gestation were surgically instrumented with catheters. Cardiorespiratory parameters were monitored, and biochemical analyses were performed with the blood samples. During the insult seven fetuses were given FBP (500 mg/kg) and six were given iso-osmotic saline, and hippocampal neuronal damage was examined histologically and scored. Cardiorespiratory changes were the same in both groups, and there was no neuroprotective effect of FBP in this study. However the decrease of serum total Ca level implied the Ca- chelating effect of FBP.

The effect of pregnancy on cytochrome P4501A2, xanthine oxidase, and N-acetyltransferase activities in humans

OBJECTIVE

Our objective was to evaluate the activity of cytochrome P4501A2 (CYP1A2), xanthine oxidase (XO), and N-acetyltransferase 2 (NAT2) from early to late pregnancy and after delivery.

METHODS

Twelve women were studied on three occasions during pregnancy (early, 8-16 weeks' gestation; middle, 20-28 weeks' gestation; and late, 32-39 weeks' gestation) and about 1 month after delivery. Caffeine was used as a metabolic probe. After the women ingested a can or a bottle of caffeine-containing soft drink, urine samples were collected for 12 hours. The caffeine metabolites measured were 5-acetylamino-6-amino-3-methyluracil (AAMU), 1-methylxanthine (1X), 1-methyl-uric acid (1U), 1,7-dimethyl-uric acid (17U), and 1,7-dimethylxanthine (17X). The hepatic enzyme activities were estimated by the urinary caffeine metabolic ratios as follows: CYP1A2 = (AAMU + 1X + 1U)/17U; XO = 1U/(1X + 1U); NAT2 = AAMU/(AAMU + 1X + 1U).

RESULTS

Statistically significant differences were found in CYP1A2 (P < .0001) and NAT2 (P < .01). The mean metabolic ratios for CYP1A2 during pregnancy (6.80, 5.18, and 4.97 for the early phase, middle phase, and late phase, respectively) were significantly lower than the ratio after delivery (10.39). The mean metabolic ratio for NAT2 in the early phase (0.57) was significantly lower than after delivery (0.66). There was no significant difference in metabolic ratios for XO during pregnancy and after delivery.

CONCLUSION

The data demonstrate that pregnancy influences CYP1A2 and NAT2 activity. CYP1A2 activity decreases not only in late pregnancy but also in early and middle pregnancy.

FISH examination of lymphocytes from Mayak workers for assessment of translocation induction rate under chronic radiation exposures

PURPOSE

To estimate the translocation-induction rate under chronic exposure conditions by measuring chromosome aberration frequencies in lymphocytes from Mayak nuclear workers using fluorescence in situ hybridization (FISH).

MATERIALS AND METHODS

Lymphocytes were examined from 27 nuclear workers at the Mayak Production Association and two control individuals using FISH with probes for chromosomes 1, 2 and 4. Official doses derived from worker film-badge records varied from 0 to 8.50 Gy.

RESULTS

The mean (+/-SD) genome-equivalent translocation frequency (F(G)) was 2.30 (+/-0.75)% in the zero-dose group (n = 7), and Poisson regression analysis provided the best-fit equation of F(G)(%) = 2.96(+/-0.39) + 0.69(+/-0.14)D + 0.12(+/-0.05)A, where D is the film-badge-derived dose (Gy), and A is age centred at 67 years. The induction rate would increase to nearly 1% Gy(-1) if the radiation dose to bone marrow, one of the major organs for lymphocytes and where their precursor cells reside, is considered.

CONCLUSION

The estimated induction rate in vivo appeared substantially smaller than linear coefficients estimated from various in vitro studies.

Isolation and characterization of a gene specific to lager brewing yeast that encodes a branched-chain amino acid permease

We found two types of branched-chain amino acid permease gene (BAP2) in the lager brewing yeast Saccharomyces pastorianus BH-225 and cloned one type of BAP2 gene (Lg-BAP2), which is identical to that of Saccharomyces bayanus (by-BAP2-1). The other BAP2 gene of the lager brewing yeast (cer-BAP2) is very similar to the Saccharomyces cerevisiae BAP2 gene. This result substantiates the notion that lager brewing yeast is a hybrid of S. cerevisiae and S. bayanus. The amino acid sequence homology between S. cerevisiae Bap2p and Lg-Bap2p was 88%. The transcription of Lg-BAP2 was not induced by the addition of leucine to the growth medium, while that of cer-BAP2 was induced. The transcription of Lg-BAP2 was repressed by the presence of ethanol and weak organic acid, while that of cer-BAP2 was not affected by these compounds. Furthermore, Northern analysis during beer fermentation revealed that the transcription of Lg-BAP2 was repressed at the beginning of the fermentation, while cer-BAP2 was highly expressed throughout the fermentation. These results suggest that the transcription of Lg-BAP2 is regulated differently from that of cer-BAP2 in lager brewing yeasts.

Transgene expression of thioredoxin (TRX/ADF) protects against 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced hematotoxicity

TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) has a variety of toxic effects on a number of organs, including the hematopoietic system. The importance of TCDD-induced oxidative stress has been evaluated in several target organs. However, its role in hematotoxicity remains poorly understood, although bone marrow is known to produce reactive oxygen species. The aim of this study is to evaluate not only the contribution of oxidative stress to TCDD-induced hematotoxicity but also the protective function of TRX/ADF, a known anti-oxidative stress agent, on the hematotoxicity of TCDD in ADF wild-type (WT) and transgenic (Tg) mice. WT and Tg mice received a single intraperitoneal injection of 20 microg TCDD/kg. One day after the treatment, blood and bone marrow cellularity was measured and bone marrow levels of granulotyce/macrophage colony-forming units were determined in the in vitro colony assay. The expression of human TRX transgene by their bone marrow cells was analyzed by Western blot electrophoresis. Our results showed that overexpression of TRX/ADF protects against TCDD-induced hematotoxicity, indicating that induction of oxidative stress that results in disruption of redox regulation may be an important mechanism in TCDD-induced bone marrow toxicity. Moreover, we detected a significant decrease of AhR mRNA levels in bone marrow cells of Tg mice following TCDD treatment, suggesting a biological role of TRX/ADF in the AhR-mediated pathway through which TCDD induces oxidative stress.

Intramedullary schwannoma of the spinal cord: report of two cases

We report magnetic resonance findings in the intramedullary schwannoma of the cervical spinal cord in two patients. In both cases, the solid portions of the tumours enhanced intensely after administration of Gd-DTPA and the enhanced border was sharply delineated from the adjacent spinal cord. Schwannomas should be considered in the differential diagnosis of intramedullary tumours when magnetic resonance images show a strongly enhancing mass with sharply delineated borders.

Gender- or age-related binding characteristics of valproic acid to serum proteins in adult patients with epilepsy

The aim of the present study was to determine the gender- or age-related binding characteristics of valproic acid (VPA) to serum proteins in the adult population. Serum samples examined in the study were obtained from 70 adult patients (36 males, 34 females) with epilepsy on VPA monotherapy. Their age ranged from 16 to 68 years (mean age with (SD), 37.7 (15.7) years; <45 years, n=44; >/=45 years, n=26). The in vivo population binding parameters of VPA to serum proteins and theoretical minimal unbound serum VPA fraction (Fu) were determined using an equation derived from the Scatchard equation in: (1), all; (2), male and female subgroups; and (3), younger (<45 years) and older (>/=45 years) subgroups. There was a significant difference in serum concentration of unbound VPA between male and female patients. The mean association constant (K) was 0.010 microM(-1) in all, male, and female patients. The mean total concentration of binding sites (n(Pt)) was 1453 microM for all patients, and 1561 and 1394 microM for male and female patients, respectively. The Fu was 0.064 for all patients, and 0.060 and 0.067 for male and female patients, respectively. There were no significant differences in the binding characteristics of VPA to serum proteins between the male and female groups. On the other hand, there were significant differences in the serum albumin concentration and molar concentration ratio of free fatty acids to albumin in serum between the younger and older patients. The mean value of K was 0.016 microM(-1) for the younger patients and 0.007 microM (-1) for the older patients. The mean n(Pt) was 1157 microM for the younger patients and 1703 microM for the older patients. The Fu was 0.051 for the younger patients and 0.077 for the older patients. Thus, significant differences were observed in the binding characteristics of VPA to serum proteins between the younger and older groups. Our results show that age, but not gender, has significant influences on the binding characteristics of VPA to serum proteins in our patient population.

Effect of temperature on serum protein binding characteristics of phenytoin in monotherapy paediatric patients with epilepsy

OBJECTIVES

To determine the effects of temperature on binding characteristics of phenytoin to serum proteins in paediatric patients with epilepsy.

METHOD

Serum samples examined in the study were obtained from 41 paediatric patients (23 male, 18 female) with epilepsy on phenytoin monotherapy. Their age ranged from 1 to 15 years (mean +/- SD, 10;2 +/- 4;0 years). Protein binding of phenytoin was evaluated by ultrafiltration under current laboratory routine conditions (25 +/- 3 degrees C) or at a temperature of 37 degrees C. The in vivo binding parameters of phenytoin to serum proteins were determined using a binding equation derived from the Scatchard equation for a one-site binding model.

RESULTS

Significant differences were observed in serum concentrations of unbound phenytoin at the two temperatures (P < 0;05). The mean association constant L/micromol (K) of phenytoin to serum proteins is 0.016 L/micromol at 25 +/- 3 degrees C and 0;009 L/micromol at 37 degrees C, while mean total concentration of binding sites (n(Pt)) seems to be similar between the two temperatures (682 micromol/L for 25 +/- 3 degrees C and 746 micromol/L for 37 degrees C). Significant differences were observed in binding characteristics of phenytoin to serum proteins for the different temperature conditions of ultrafiltration (P < 0;05).

CONCLUSION

Our study confirms that binding affinity for phenytoin-serum protein interaction is approximately 44% lower at 37 degrees C than at 25 +/- 3 degrees C and consequently, binding potential (K.n(Pt)) is approximately 38% lower at 37 degrees C than at 25 +/- 3 degrees C.

Design and evaluation of PCR primers to amplify bacterial 16S ribosomal DNA fragments used for community fingerprinting

Denaturing gradient gel electrophoresis of PCR-amplified 16S ribosomal DNA (rDNA) fragments has frequently been applied to the fingerprinting of natural bacterial populations (PCR/DGGE). In this study, sequences of bacterial universal primers frequently used in PCR/DGGE were compared with 16S rDNA sequences that represent recently proposed divisions in the domain Bacteria. We found mismatches in 16S rDNA sequences from some groups of bacteria. Inosine residues were then introduced into the bacterial universal primers to reduce amplification biases caused by these mismatches. Using the improved primers, phylotypes affiliated with Verrucomicrobia and candidate division OP11, were detected in DGGE fingerprints of groundwater populations, which have not been detected by PCR/DGGE with conventional universal primers.

Field evaluation of chicken egg yolk immunoglobulins specific for bovine rotavirus in neonatal calves

The oral efficacy of chicken egg yolk immunoglobulins (yIg) specific for bovine rotavirus (BRV) serotypes G6 and G10 in protecting neonatal calves was examined in a herd of cattle under field conditions. In one of the three trials, yIg-treated calves tested under high relative humidity (RH) showed a significantly increased mean body weight (P < 0.05) and a decrease in number of calves shedding high titer of BRV (G6) in stool compared to control calves (P < 0.01), suggesting that our yIg product was effective in a field condition with an epidemic outbreak of BRV diarrhea.

Adherence protects the binding sites of Helicobacter pylori urease from acid-induced damage

Colonization by Helicobacter pylori partly depends on acid-dependent adherence by urease to gastric mucin. To further verify the relevance of urease adherence to colonization, the influence of acidity on the binding sites of H. pylori urease was investigated. When enzyme-based in vitro ligand capture assays were used, the effect of acidity on the binding site of H. pylori urease was determined against a backdrop medium consisting of acidic buffers simulating the luminal side of gastric mucus. A high degree of stability was exhibited by adherent urease, suggesting a pivotal role by the denatured enzyme in the persistence of the bacterium within the acidified compartment of gastric mucus.

Adsorption effect of activated charcoal on enterohemorrhagic Escherichia coli

The adsorption property of activated charcoal on verotoxin (VT)-producing Escherichia coli (VTEC) was examined using E. coli O157:H7. In the present study, E. coli O157:H7 strains were effectively adsorbed by activated charcoal. Adsorption was dose-dependent, and the maximum adsorption occurred within 5 min. At 10 mg of activated charcoal, bacteria tested were completely adsorbed. Activated charcoal also had the capacity to adsorb toxin (verotoxin 2) activity from the bacterial extract. Furthermore, the adsorption efficiency of activated charcoal for the normal bacterial flora in the intestine was assessed using Enterococcus faecium, Bifidobacterium thermophilum, and Lactobacillus acidophilus. Activated charcoal showed lower binding capacity to the normal bacterial flora tested than that to E. coli O157:H7 strains. These results suggest that activated charcoal could be a good adsorbent system for the removal of VTEC and verotoxin.

Mechanism of action of benzene toxicity: cell cycle suppression in hemopoietic progenitor cells (CFU-GM)

The aim of this study was to clarify previously reported controversial data and hypotheses concerning the effect of benzene on the cell cycle of hemopoietic stem cells. In this study, the bromodeoxyuridine UV (BUUV) suicide assay was performed in normal C57BL/6 and p53 knockout (KO) C57BL/6 mice during and after exposure to 300 ppm of benzene for 2 weeks. Our kinetic studies revealed that the cell cycle of hemopoietic myeloid progenitor cells (colony-forming unit granulocyte-macrophage [CFU-GM]), rather than being stimulated, was suppressed by exposure to benzene. The fraction of CFU-GM in S phase was significantly depressed, from 37.1% in controls to 16.3% in normal mice. BrdUrd incorporation in both groups revealed significantly different slopes for untreated and benzene-exposed normal C57BL/6 mice. p53 appeared to induce suppression of both the number and the cycling fraction of hemopoietic progenitor cells, as demonstrated by the lack of benzene-induced suppression of these parameters in p53 KO mice. The likelihood that suppression of bone marrow cellularity and cell cycling is mediated by p53 was supported by the upregulation of p21, a cyclin-dependent kinase inhibitor. Our present study revealed the mechanism of action of benzene hematotoxicity. Benzene suppresses the cell cycle by p53-mediated overexpression of p21, a cyclin-dependent kinase inhibitor, resulting not simply in suppression of hemopoiesis but rather in a dynamic change of hemopoiesis during and after benzene exposure. Thus, the controversies raised by previously reported data are resolved by our present findings of hemopoietic stem cell kinetics.