Glutathione-S-transferase activity toward aflatoxin epoxide in livers of mastomys and other rodents

In order to study the liver glutathione-S-transferase (GST) activity toward aflatoxin B1 (AFB1) epoxide in mastomys in comparison with other rodents, we performed in vitro studies of the cytosolic GST activity toward AFB1-epoxide using mastomys, rat, mouse and hamster liver. Also AFB1 metabolism by liver microsomes including formation of AFB1-DNA adducts was studied. Cytosolic GST activity toward AFB1-epoxide was highest in mastomys liver, and higher in the hamster and mouse livers than in the rat liver, correlating well with the differences of the sensitivity of these species to the toxicity of AFB1. However, no relationship was noted between the sensitivity of a given species to the toxicity of AFB1 and the microsomal activity of binding of AFB1 to DNA or metabolizing AFB1 to AFM1, AFQ1 and AFP1. These results demonstrate the importance of the GST mediated AFB1-epoxide conjugation with glutathione in determining the differing sensitivities of these species to AFB1 toxicity. The extremely high activity of GST in mastomys indicates that this species would be a good model animal for studying GST toward AFB1-epoxide.

Polychlorinated dibenzo-p-dioxin and dibenzofuran concentrations in serum samples of workers at intermittently burning municipal waste incinerators in Japan

OBJECTIVES

To find whether or not incinerator workers employed at intermittently burning municipal incineration plants are exposed to high concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs).

METHODS

20 Workers employed at three municipal waste incineration plants (incinerator workers) and 20 controls were studied. The previous job, dietary, smoking, and body weight and height were obtained from a questionnaire survey. Concentrations of PCDDs and PCDFs were measured in serum samples of the workers and the deposited dust of the plants. The influence of occupational exposure on concentrations of PCDDs and PCDFs in serum samples was examined by multiple regression analysis.

RESULTS

Dust analysis showed that dominant constituents were octachlorodibenzo-p-dioxin (OCDD) and 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (HpCDD) among the PCDDs, and 1,2,3,4,6,7,8-heptachlorodibenzofuran (HpCDF) and octachlorodibenzofuran (OCDF) among the PCDFs. The toxicity equivalents (TEQs) of summed PCDDs and PCDFs in the deposited dust were 0.91, 33, and 11 ng TEQ/g, respectively, for plants I, II, and III. The means of TEQ in serum samples of summed PCDDs and PCDFs in the incinerator workers and controls were 22.8 and 16.4 pg TEQ/g lipid for area I, 29.4 and 19.3 pg TEQ/g lipid for area II, and 22.8 and 24.9 pg TEQ/g lipid for area III, which were almost the same as for the general population of Japan. No significant differences in the TEQ of PCDDs and TEQ of PCDDs and PCDDs were found between the incinerator workers and the controls. However, the TEQ of PCDFs was significantly higher among the incinerator workers in areas I and II, and the 1,2,3,4,6,7,8-HpCDF concentration was also significantly higher for all three areas. When the occupational exposure index for each constituent of PCDDs and PCDFs was defined as the product of the duration of employment at the incineration plant and the concentration of the constituent in the deposited dust, multiple regression analysis showed that the concentrations of HxCDF, HpCDF, and TEQ of PCDFs in serum samples increased with the occupational exposure index. The multiple regression analysis also suggested that significant factors affecting the concentrations in serum samples were area for HxCDD, age for TCDD, PeCDD, PeCDF, TEQ of PCDDs, TEQ of PCDFs, and TEQ of summed PCDDs and PCDFs, and BMI for HxCDD, HpCDD, and OCDD.

CONCLUSION

This study showed that incinerator workers employed at intermittently burning incineration plants were not necessarily exposed to high concentrations of PCDDs and PCDFs. However, the increases in the concentrations in serum of HxCDF, HpCDF and TEQ of PCDFs with the occupational exposure index suggest that the incinerator workers had inhaled dust containing PCDDs and PCDFs during their work.

Dietary obesity-resistance and muscle oxidative enzyme activities of the fast-twitch fibre dominant rat

OBJECTIVES

To clarify whether the muscle fibre composition and/or muscle oxidative enzyme activity are related to dietary body weight gain and abdominal fat accumulation.

METHODS

Genetically fast-twitch fibre dominant rats (FFDR) and control rats (CR) were divided into low-fat (20% of energy from fat) or high-fat (60% of energy from fat) diet groups: CR with a low-fat diet (CL); CR with a high-fat diet (CH); FFDR with a low-fat diet (FL); and FFDR with a high-fat diet (FH). After 6 weeks of following such diets, the body weight gain, abdominal fat content, food intake, muscle fibre composition and oxidative enzyme activities were estimated.

RESULTS

The total body weight gain in CH was from 18 to 62% higher than in the other groups (P<0.05) and percentage abdominal fat in CH was also from 26 to 61% higher than in the other groups (P<0.05), while the energy intake did not differ among the groups. The percentage of type IIX fibres of M. gastrocnemius in FL (33.4%) and FH (36.3%) were higher than in CL (16.8%) and CH (19.8%; P<0.05), and the type IIA fibres of M. soleus in FL (14.1%) and FH (11.8%) were higher than in CL (2.0%) and CH (3.5%; P<0.05). The citrate synthase (CS) activity of of M. plantaris in FL and FH were higher than CL (46 and 54%, respectively, P<0.05). beta-Hydroxyacyl CoA dehydrogenase (HAD) activity in FL and FH were higher than in CL (21 and 31%, respectively, P<0.05) and that in FH was higher than CH (23%, P<0.05). On the other hand, the enzyme activities of M. gastrocnemius and soleus were identical among the groups.

CONCLUSION

The FFDR was more obesity-resistant than the CR after a high-fat diet. These results suggest that the muscle oxidative capacity rather than muscle fibre composition is a possible determinant of obesity.

Relationship between insulin resistance, sex hormones and sex hormone-binding globulin in the serum lipid and lipoprotein profiles of Japanese postmenopausal women

The purpose of the present study was to investigate the relationship between insulin resistance, sex hormones and sex hormone-binding globulin (SHBG) in regard to the serum lipid and lipoprotein profiles of 82 Japanese postmenopausal women. A multiple regression analysis for lipids, lipoproteins, and apoproteins as dependent variables was performed. All regression models included the following variables as potential independent variables; BMI, percentage of body fat, waist-hip ratio, free testosterone (Free T) and SHBG. In addition, model A included insulin resistance evaluated by HOMA-R and model B included fasting insulin (FIRI). In model A, both Free T and HOMA-R were independent predictors of total-C (TC)/high-density lipoprotein-C (HDL-C) and low-density lipoprotein-C (LDL-C)/HDL-C. The BMI was independently associated with HDL-C. The Free T was a single independent predictor of TC and LDL-C. Both BMI and HOMA-R were independent predictors of triglyceride (TG). In addition, SHBG was also independently associated with apoprotein B (Apo B) and Apo B/Apo AI. In model B, FIRI was an independent predictor of lipid metabolism with similar results to those observed in model A. These results suggest that the lipid characteristics in postmenopausal women might be associated with insulin resistance and/or hyperinsulinemia, and relative hyperandrogenicity which thus induces an increase in the amount of Free T and a decrease in the SHBG within physiological ranges.

Fluctuations in plasma macrophage colony-stimulating factor levels during autologous peripheral blood stem cell transplantation for haematologic diseases

Plasma macrophage colony-stimulating factor (M-CSF) levels were measured in 13 haematologic patients treated with autologous peripheral blood stem cell transplantation (PBSCT). Six of the patients showed an increase in M-CSF peak levels (>3000 pg/ml) during the conditioning and stem cell infusion period. The peak levels of M-CSF in this phase correlated with thrombomodulin levels, indicating the endothelial origin of plasma M-CSF. However, the M-CSF levels were not influenced by TNFalpha. More patients with high M-CSF levels (>5000 pg/ml) suffered from organ failure than those with lower M-CSF levels. These results suggest that high M-CSF levels may correlate with cellular or organ damage in patients treated with PBSCT.

Improved method for detection of Vibrio parahaemolyticus in seafood

We have developed a new, effective procedure for detecting Vibrio parahaemolyticus in seafoods using enrichment and plating onto a chromogenic agar medium. Samples were cultured in salt Trypticase soy broth, which is a nonselective medium, and then a portion of the culture was cultured with salt polymyxin broth, which is a selective medium for V. parahaemolyticus. This two-step enrichment was more effective than the one-step enrichment in salt polymyxin broth alone. The enrichment cultures were then plated onto a new chromogenic agar containing substrates for beta-galactosidase. The V. parahaemolyticus colonies developed a purple color on this growth medium that distinguished them from other related bacterial strains. V. parahaemolyticus was isolated more frequently from naturally contaminated seafood samples using the chromogenic agar than thiosulfate citrate bile salts sucrose agar medium, which is currently used for the isolation of V. parahaemolyticus. Our findings suggest that this new enrichment and isolation scheme is more sensitive and accurate for identifying V. parahaemolyticus in seafood samples than previously used methods.

[Detection of TDH-producing Vibrio parahaemolyticus O3:K6 from naturally contaminated shellfish using an immunomagnetic separation method and chromogenic agar medium]

We attempted to isolate TDH-producing Vibrio parahaemolyticus O3:K6 from shellfish. Asari samples were incubated with TSB supplemented with 2% (w/v) NaCl for 6 h, and then the 6-h cultures were incubated with salt polymyxin broth for 18 h. After the two-step enrichment, a 1 ml portion of the culture was treated with magnetic beads coated with K6 antibody for immunoconcentration of V. parahaemolyticus O3:K6. The immunoconcentrated and untreated cultures were plated onto a chromogenic agar and TCBS agar media for isolation of V. parahaemolyticus. TDH-producing V. parahaemolyticus O3:K6 was isolated from 3 out of 66 lots (4.5%) of naturally contaminated Asari. Six of 4,265 colonies suspected as V. parahaemolyticus (0.14%) were TDH-producing V. parahaemolyticus O3:K6.

Numerical analysis of spectra of the Frobenius-Perron operator of a noisy one-dimensional mapping: toward a theory of stochastic bifurcations

A different method to detect the stochastic bifurcation point of a one-dimensional mapping in the presence of noise is proposed. This method analyzes the eigenvalues and eigenfunctions of the noisy Frobenius-Perron operator. The invariant density or the eigenfunction of the eigenvalue 1 of the operator possesses "static" information of the noisy one-dimensional dynamics while the other eigenvalues and eigenfunctions have "dynamic" information. Clear bifurcation phenomena have been observed in a noisy sine-circle map and both stochastic saddle-node and period-doubling bifurcation points have been successfully defined in terms of the eigenvalues.

Creatine kinase gene mutation in a patient with muscle creatine kinase deficiency

BACKGROUND

We describe a 56-year-old woman admitted to the hospital with a diagnosis of acute myocardial infarction without an increase of serum creatine kinase (CK) activity during her clinical course. She died on the 11th hospital day, and the diagnosis was confirmed by autopsy. The patient had had no previous muscular symptoms.

METHODS

Expression of the CK-muscle (CK-M) protein in cardiac tissue was examined by immunoblotting and immunochemical staining. CK-M mRNA expression was estimated by semiquantitative reverse transcription-PCR. Gene structure of CK-M was determined by Southern blotting and direct sequencing of 2251 bp. Existence of a point mutation in the CK-M gene was examined by restriction fragment length polymorphism analysis of PCR products (PCR-RFLP) in the patient and in 108 controls.

RESULTS

CK-M protein in the myocardial tissue of the patient was substantially lower (103 +/- 7 ng/mg protein) than in control myocardial tissue (35 800 +/- 2860 ng/mg protein). Immunoreactive CK-M in the patient tissue sample was 0.3% of the value for the control sample. CK-M mRNA was 53-fold less in the patient sample compared with the control. This very low expression of CK-M mRNA was considered to be the primary reason for CK-M deficiency. Direct sequencing revealed a point mutation at residue 54 in exon 2, which was specific for the patient. No other abnormalities were found in the CK-M gene of the patient.

CONCLUSIONS

This report identifies a molecular abnormality in human CK deficiency and discusses the physiologic relevance of CK-M.

Effects of chemotherapy on invasion and metastasis of oral cavity cancer in mice

BACKGROUND

Using an orthotopic implantation model in which oral cancer invasion and metastasis can be reproduced, we investigated the inhibitory effects of anticancer agents on invasion and metastasis.

METHODS

A highly invasive and metastatic human oral squamous cell carcinoma cell line, OSC-19, was implanted into the oral floor of nude mice, and cisplatin or peplomycin was administered to the mice 7 or 14 days after implantation. The effects of each anticancer drug and different administration timings on cancer invasion and metastasis were investigated.

RESULTS

Tumor size and the ratio of proliferating cell nuclear antigen-positive cells was significantly reduced. In the control group, the tumors showed grade 4C mode of invasion, whereas in the groups treated with anticancer drugs, grade 3 was observed in 77.3% of the mice, with an inhibitory effect on tumor invasion being observed. The rate of metastasis in the cervical lymph node was significantly decreased in the groups treated with the cisplatin or peplomycin on day 7 after implantation. The tumor stage progression in the metastatic lymph nodes was also inhibited.

CONCLUSIONS

Chemotherapy is effective not only for tumor diminution but also for inhibiting invasion and metastasis. In light of these effects, administration of anticancer drugs may be clinically useful in this regard.

Platelet-derived growth factor and its receptors are expressed in areas of both active inflammation and active fibrosis in inflammatory bowel disease

The aim of the present study is to clarify in situ expression of platelet-derived growth factor (PDGF) and its receptors in different phases of inflammatory bowel disease (IBD). Tissues samples were obtained from 20 patients with ulcerative colitis (UC) and 29 with Crohn's disease (CD) at surgery. In situ hybridization and immunohistochemistry on frozen sections were performed for PDGF-A and -B and its alpha and beta receptors (alphaR and betaR). The area of active inflammation was infiltrated by abundant polymorphonuclear and mononuclear leukocytes, of which the latter expressed mRNA and proteins of PDGF-A, -B, and -alphaR and mRNA for PDGF-betaR. The area of active fibrosis, characterized by activated fibroblasts/ myofibroblasts, was juxtaposed to ulceration, which is induced as a repair process to tissue destruction. In these areas, activated fibroblasts/myofibroblasts were positive for mRNA and protein of PDGF-A, -B, -alphaR, and -betaR. The expression of PDGF-A, -B, and -alphaR declined significantly in the scar area. Our results suggest that PDGF is not only important as an inducer of fibrosis in the repair phase but also it is involved in the active inflammatory phase possibly as a chemoattractant for mononuclear inflammatory cells.

Detection of antinuclear antibodies by use of an enzyme immunoassay with nuclear HEp-2 cell extract and recombinant antigens: comparison with immunofluorescence assay in 307 patients

BACKGROUND

A new enzyme immunoassay (EIA) for automated detection of antinuclear antibodies (ANAs) uses a mixture of HEp-2 cell extracts and multiple recombinant nuclear antigens immobilized on beads. We compared this EIA and an immunofluorescence (IF) assay in a large group of patients and controls.

METHODS

We studied 492 healthy individuals and 307 patients with connective tissue diseases (CTDs). Sera were tested by an automated EIA (COBAS Core HEp2 ANA EIA; Roche Diagnostics) and IF. Samples were also tested for eight disease-specific antibodies, including antibodies against U1RNP, Sm, SSA/Ro, SSB/La, Scl-70, Jo-1, dsDNA, and centromere.

RESULTS

Areas under ROC curves for the EIA were greater than (P = 0.008-0.012) or numerically identical to areas for the IF method for each of six CTDs studied. ROC areas for EIA were 0.98 (95% confidence interval, 0.95-0.99), 0.99 (0.96-1.00), and 0.99 (0.98-1.00) in systemic lupus erythematosus (n = 111), systemic sclerosis (n = 39), and mixed connective tissue disease (n = 33), respectively. For all 258 CTD patients with conditions other than rheumatoid arthritis (RA), the sensitivity and specificity of the IF method at a cutoff dilution of 1:40 were 92% and 65%, respectively, vs 93% and 79% for the EIA at a cutoff of 0.6. For the IF method at a cutoff dilution of 1:160, sensitivity and specificity were 81% and 87%, respectively, vs 84% and 94%, respectively, for the EIA at a cutoff of 0.9. For 207 sera containing at least one of eight disease-specific ANAs, positivities for the EIA and the IF method were 97.1% and 97.6%, respectively, at cutoffs of 0.6 and 1:40 (P = 0.76).

CONCLUSIONS

An EIA that can be performed by a fully automated instrument distinguishes CTDs (except RA) from healthy individuals with both higher sensitivity and specificity than the IF method when the cutoff index was set at 0.9. Moreover, it can be used to exclude the presence of disease-specific ANAs by setting the cutoff index at 0.6 with almost the same efficacy as the IF method.

[Incidence and prognosis of, and risk factors for the home-bound in a community elderly population]

This longitudinal study examined numbers of homebound and bed bound individuals over time, and risk factors in a rural community elderly populations. A total of 731 older persons who needed no assistance of another person in traveling from their homes participated in the baseline survey in 1992 and were assessed annually for their ability to travel for subsequent six-years. We defined operationally a homebound status as the necessity for assistance of another person to be able to leave home, but without being bedbound. During the follow-up period, 86 homebound (23.7 per 1,000 person-years) and 32 bedbound cases (8.4 per 1,000 person-years) were noted, the former being 2.8 times more likely to occur. Of the newly bound cases 26% returned to a state capable of leaving home by themselves one year later, and maintained this independent living level even two years later. Of the other cases who remained as homebound or bedbound one year later, only one (1/31) had returned to independent living after two years; most of them became bedbound at home, hospital admitted or deceased. Stepwise multiple logistic regression analysis showed that independent risk factors for the homebound include older age, male gender, slower walking speed, history of hospital admission in the previous year, lower masticatory ability, and higher level of serum beta 2-microglobin. These results indicate that health promotion programs for prevention of becoming homebound among community elderly people should target more intensively assistance to maintaining walking and masticatory ability. In addition, public health professionals should pay more attention to elderly people shortly after hospital discharge.

Laying season and egg shell cracks on the growth of Salmonella enteritidis in the egg albumen during storage

We studied the effects of laying seasons and egg shell cracks on the ability of egg albumen to support the growth of Salmonella Enteritidis (SE) in eggs. Hens eggs used were those laid in February, June, and October in a farm in Japan and stored at 10, 20, and 30 degrees C, and at 30 degrees C after storage at 10 degrees C, immediately after receipt or after cracking the shell. At several-day intervals during storage, the egg contents were poured into a dish, SE was inoculated into albumen, and then the growth of SE during 3 days incubation at 18 degrees C was measured. The results demonstrated that storage temperature and laying season affected the growth of SE in the egg albumen. The proportion of eggs upon which albumen allowed the growth of SE was higher in the eggs stored at 30 degrees C than those stored at 10 degrees C. The growth of SE in eggs was lowest in the following order of laying: February, October, and June. SE grew preferably in albumen of cracked eggs than intact eggs.

Weekly 1 hour paclitaxel infusion in patients with recurrent gynecological tumors: a pilot study

BACKGROUND

Intensifying the dose of paclitaxel given in a weekly schedule is useful towards improving the therapeutic index of paclitaxel in treating a variety of advanced and recurrent malignancies and is suitable for outpatient administration. This pilot study was carried out to evaluate the safety of weekly paclitaxel administration by 1 h infusion in the outpatient setting.

METHODS

Eleven patients with recurrent gynecological tumors who had previously been treated with at least one platinum-based chemotherapy regimen participated in the study between May 1999 and March 2000. Paclitaxel was given at a dose of 70 mg/m(2 ) as a 1 h infusion every week for at least 20 consecutive weeks unless lesions became progressive. Intravenous dexamethasone and cimetidine and oral diphenhydramine were administered 30 min before paclitaxel infusion.

RESULTS

The 11 patients received a total of 166 cycles of therapy. All patients received 70 mg/m(2 ) doses of paclitaxel without treatment delay. No hypersensitivity reactions were elicited. Grade 3 or 4 leukopenia and neutropenia occurred in 9 and 36% of the patients, respectively. Granulocyte colony-stimulating factor was required for only one patient and no patients experienced febrile neutropenia. Neurotoxicity was the most serious adverse effect and all patients experienced grade 1 or 2 peripheral neuropathy. Grade 1 or 2 myalgias were observed in 45% of the patients. Alopecia was universal. No Grade 3 or higher non-hematological toxicities were observed.

CONCLUSION

Weekly 1 h paclitaxel administration is considered safe as a salvage therapy for recurrent gynecological tumors, making its use more convenient and easier in the outpatient setting. The current results support further evaluation.

Complex nonlinear dynamics of the Hodgkin-Huxley equations induced by time scale changes

The Hodgkin-Huxley equations with a slight modification are investigated, in which the inactivation process (h) of sodium channels or the activation process of potassium channels (n) is slowed down. We show that the equations produce a variety of action potential waveforms ranging from a plateau potential, such as in heart muscle cells, to chaotic bursting firings. When h is slowed down--differently from the case of n variable being slow --chaotic bursting oscillations are observed for a wide range of parameter values although both variables cause a decrease in the membrane potential. The underlying nonlinear dynamics of various action potentials are analyzed using bifurcation theory and a so-called slow-fast decomposition analysis. It is shown that a simple topological property of the equilibrium curves of slow and fast subsystems is essential to the production of chaotic oscillations, and this is the cause of the large difference in global firing characteristics between the h-slow and n-slow cases.

Quantification of red blood cell fragmentation by automated haematology analyser XE-2100

The extent of red blood cell fragmentation in peripheral blood is useful for diagnosis and follow-up in many diseases, e.g. haemolytic uremic syndrome, transplantation-associated thrombotic microangiopathy (BMT-TMA). However, this quantification still relies on manual counting of fragmented red cells on blood smears. We have developed a quantification system by gating a fixed area of fragmented red blood cells (Gate 1) on an automated haematology analyser (XE-2100, Sysmex Co., Kobe, Japan). The fragmented red cell percentage (FRC%) calculated with this system, from 100 samples, was highly correlated with the manual count (r=0.902, P < 0.0001). Because microcytic anaemia specimens usually occupy a lower position on the XE-2100 scattergram, with microcytic cells overlapping Gate 1 and causing a spuriously high FRC% calculation, a supplementary gate (Gate 2) was added. Using the particle number in this gate as well as in Gate 1, a revised method for such samples was developed and its validity confirmed (revised FRC% correlated with a manual count for 10 subjects (P < 0.001). Because this gating system can be programmed on any XE-2100, it is likely to prove useful for accurate quantification of red blood cell fragmentation and for the monitoring of the development of BMT-TMA.

Polymorphisms of the mannose binding lectin gene in patients with Sjögren's syndrome

OBJECTIVE

To investigate polymorphisms of both codon 54 allele and promoter variants of the mannose binding lectin (MBL) gene in patients with primary Sjögren's syndrome (SS).

METHODS

Polymorphisms of codon 54 allele and promoter variants of the MBL gene in 104 patients with SS and 143 healthy controls were determined by polymerase chain reaction-restriction fragment length polymorphism and allele specific polymerase chain reaction respectively.

RESULTS

The allele frequency of the wild type of MBL codon 54 was significantly higher in patients with SS than in controls (0.836 v 0.741; p=0.011), and the frequency of the homozygous wild type of MBL codon 54 was significantly higher in patients with SS than in controls (0.692 v 0.539; p=0.024). On the other hand, the allele frequencies of the MBL promoter gene did not differ between patients and controls (chi(2)=4.01, df=2, p=0.135).

CONCLUSION

The polymorphism of the MBL gene may be one of the genetic factors that determines susceptibility to SS.

[A modified administrated schedule for combination therapy with irinotecan and cisplatin as a neoadjuvant chemotherapy in locally advanced cervical cancer--a report of 2 cases as a pilot study]

To shorten the treatment term of neoadjuvant chemotherapy (NAC) for locally advanced cervical cancer, a combination of irinotecan (CPT-11) and cisplatin was administered on a modified administrated schedule for 2 eligible patients as a pilot study. CPT-11 70 mg/m2 was administered (div) on days 1 and 8, followed by cisplatin 70 mg/m2 given (div) on day 1. Treatment was repeated every 3 weeks for a total of two cycles. Both patients showed a complete clinical response. No severer toxicities were observed than with the usual regimen, and both cases could undergo radical hysterectomy after NAC. The results suggest that this modified regimen of combination of CPT-11 and cisplatin can be effective as an NAC in cases of locally advanced cervical cancer, especially in terms of shortening treatment term. This regimen is worthy of further study.

[Development of chromogenic agar medium for isolation of enterohaemorrhagic Escherichia coli O26]

Agar media for isolation of enterohaemorrhagic Escherichia coli (EHEC) have been developed primarily for E. coli O157, because this bacterium has most frequently caused EHEC infection. However, there have been few studies for isolation of other serotypes of EHEC, and media appropriate for isolation of such organisms, especially from food samples, are not yet available. Among such serotypes, E. coli O26 has often been isolated from clinical specimens from patients and animals, but not from food samples in outbreaks, because of lack of an appropriate method for isolation. In this study, we tried to develop a new chromogenic agar medium for selective isolation of E. coli O26 using the characteristics of E. coli O26. Fifteen strains of E. coli O26, 11 strains of E. coli O157 and 36 strains of other sero-types E. coli were tested for fermentation of rhamnose, cellobiose, dulcitol, salicin, raffinose, sorbitol, sucrose, lactose, mannitol, arabinose, maltose, xylose and glucose. Rhamnose was fermented by all E. coli strains except for E. coli O26. The other substrates were not effective for differentiating E. coli O26 from the other strains of E. coli. Thus the medium containing rhamnose and 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside, which is a substrate of beta-galactosidase specific to coliforms, produced a color of E. coli O26 colonies different from colors of the other bacteria. Furthermore, cefixime and sodium tellulite were added to the composition of the medium for gaining higher selectivity.

Detection of Salmonella enteritidis in shell and liquid eggs using enrichment and plating

Detection methods using various enrichment and plating media and immunoconcentration for Salmonella enteritidis in shell and liquid eggs were evaluated. For liquid egg samples naturally contaminated with S. enteritidis, pre-enrichment in 225 ml of buffered peptone water with cysteine followed by selective enrichment in 10 ml of tetrathionate broth was the superior, resulting in the detection of S. enteritidis in all samples on six of the seven types of selective agar substrate investigated. This enrichment procedure also enabled detection of S. enteritidis in most of artificially inoculated shell egg and pasteurized liquid egg samples.

Blockade of Salmonella enteritidis passage across the basolateral barriers of human intestinal epithelial cells by specific antibody

Antibodies specific to Salmonella enteritidis (S.E.) were obtained from immunized egg yolk, and their protective effects against S.E. were studied by using monolayer-cultured human intestinal epithelial cells, Caco-2 and T84. The Salmonella adherence and entry to the cells were partially inhibited by the antibodies. The antibodies inhibited the decrease in transepithelial electrical resistance (TEER) of the intestinal epithelial monolayers and IL-8 secretion of the cells induced by S.E. invasion. Also, the antibodies blocked the penetration of bacteria through the cell layer although they did not inhibit the growth of bacteria in the cells. Confocal microscopic photographs revealed the bacteria in the infected monolayer cells were bound to antibodies. These results indicate that anti-S.E. antibodies may protect the cells from destruction induced by S.E. invasion in intestinal epithelial cells in addition to the partial inhibition of adhesion and invasion of S.E. at the cell surface. Passive antibodies against invasive bacteria would be useful to prevent the migration of S.E. to blood not only at the cell surface but also inside of intestinal epithelial cells.

Immunofluorescence--still the 'gold standard' in ANA testing?

A usefulness of enzyme immunoassay (EIA)-based antinuclear antibodies (ANA) tests was evaluated in comparison with the immunofluorescence ANA assay (IF-ANA). COBAS-ANA and MBL-ANA were used, in the former a mixture of antigens extracted from HEp-2 cells and multiple recombinant antigens was immobilized on beads as the antigen, and in the latter 9 kinds of purified or recombinant proteins are immobilized on 96-well plates. We first compared an ability to differentiate 258 connective tissue disease (CTD) patients (except rheumatoid arthritis) from 257 healthy subjects between COBAS-ANA and IF-ANA. The sensitivity and specificity of COBAS-ANA were 84% and 94%, respectively, while those of IF-ANA at a cutoff dilution of 1:160 were 81% and 87%. The receiver operating characteristic (ROC) analysis showed a significant superiority of COBAS-ANA to IF-ANA. Moreover, when the cutoff index was set at 0.6, the COBAS-ANA could detect the 8 disease-specific ANAs as well as IF-ANA at a cutoff dilution of 1:40. A possible availability of MBL-ANA in a periodic health examination in certain towns was also demonstrated. Among the 1123 subjects, a total of 145 disease-specific ANAs were detected in 126 subjects. MBL-ANA could catch disease-specific ANAs with almost same efficacy of IF-ANA. Annual survey of the residents by MBL-ANA may lead to a detection of CTD patients. EIA-based ANA tests are very useful for both detecting disease-specific ANAs and screening CTD patients. We believe that EIA-ANA should be the 'gold standard' especially for screening a large number of samples, although there is some room for technical improvement.