Genetic variation of mitochondrial DNA in Phalacrocorax carbo in Japan

A Japanese resident bird, Phalacrocorax carbo hanedae (Japanese name: Kawa-u), was threatened with extinction due to deterioration of its habitat in the 1970s, but the population has since recovered thanks to environmental protection measures. This study analyzed the genetic diversity of 18 Kawa-u individuals living in the basins of the Abe and Warashina rivers in Shizuoka Prefecture, Japan. We obtained seven haplotypes of mitochondrial D-loop sequences and compared them with 49 European P. carbo D-loop haplotypes. We identified four new haplotypes but no clear genetic evidence distinguishing the Kawa-u as a distinct subspecies of P. carbo. Our results suggest the need for further surveillance of the P. carbo genetic lineage, regardless of the geographical distribution.

Effective countermeasures for Salmonella contamination in actual oilmeal-manufacturing plant in India

AIMS

Salmonella contamination in the manufacturing process of an overseas oilmeal plant was investigated and countermeasures for Salmonella contamination were evaluated.

METHODS AND RESULTS

Salmonella was detected from deposits and adhered materials inside the main processing equipment. Specifically high contamination was observed in the equipment associated with the meal cooler, with several Salmonella serovars being detected. A number of Salmonella serovars were also detected in the equipment of the fine powder recovery process. To prevent Salmonella contamination of oilmeal products, effective countermeasures that have been employed in Japan were implemented. By removing residues from the equipment and disinfecting the interior of the equipment, a significant decrease in the contamination rate of oilmeal products was achieved compared to before sanitation (P < 0·05).

CONCLUSIONS

Effective countermeasures to control Salmonella contamination in the overseas manufacturing process of oilmeal were established.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report focusing on Salmonella countermeasures in an actual oilmeal-manufacturing plant overseas.

Sequence-Based Characterization of Listeria monocytogenes Strains Isolated from Domestic Retail Meat in the Tokyo Metropolitan Area of Japan

The level of Listeria monocytogenes contamination of domestic retail meat in Tokyo, Japan, was assessed by comparison of isolates from 2004 to 2007 with those isolated before 2003. The overall prevalence of L. monocytogenes among these samples significantly diminished over time (1998-2003, 28.0%; 2004-2007, 17.6%) reflecting a significant decrease in the frequency of contamination of beef. Serotype 1/2a was isolated most frequently, reflecting a change in the predominant serotype in pork from 1/2c to 1/2a. We performed a simple genetic subtyping method based on 3 genes, iap, sigB, and actA, as well as traditional multilocus sequence typing to classify the allele types (ATs). No extensive variation among sequence types was detected. However, increased genetic diversity among the ATs of the 3 genes in the 2004-2007 isolates was evident. We identified AT 26 of the iap gene, which was not previously reported in Japanese isolates, and 6 ATs of the sigB gene, including 4 with nonsense mutations not currently registered in L. monocytogenes DNA databases. sigB is an evolutionally conserved gene that plays a role in the stress response. Our results indicate that the sigB gene may be relatively unstable among L. monocytogenes strains circulating in Japan.

Tissue toxicokinetics of perfluoro compounds with single and chronic low doses in male rats

To examine the kinetics of low doses of perfluoro compounds (PFCs), we administered perfluorohexanoic acid (C6A), perfluorooctanoic acid (C8A), perfluorononanoic acid (C9A) and perfluorooctane sulfonate (C8S) with a single oral dose (50-100 μg/kg BW), and in drinking water at 1, 5, and 25 μg/L for one and three months to male rats; and examined the distribution in the brain, heart, liver, spleen, kidney, whole blood and serum. C6A was very rapidly absorbed, distributed and eliminated from the tissues with nearly the same tissue t_1/2 of 2-3 hr. Considering serum Vd, and the tissue delivery, C6A was mainly in the serum with the lowest delivery to the brain; and no tissue accumulation was observed in the chronic studies as estimated from the single dose study. For the other PFCs, the body seemed to be an assortment of independent one-compartments with a longer elimination t_1/2 for the liver than the serum. The concentration ratio of liver/serum increased gradually from C₀ to a steady state. The high binding capacity of plasma protein may be the reason for the unusual kinetics, with only a very small fraction of free PFCs moving gradually to the liver. Although the tissue specific distribution was time dependent and different among the PFCs, the Vd and k_e of each tissue were constant throughout the study. The possibility of extremely high C6A accumulation in the human brain and liver was suggested, by comparing the steady state tissue concentration of this study with the human data reported by Pérez et al. (2013).

Genetic subtyping of Listeria monocytogenes via multiple-locus sequence typing using iap, sigB and actA

Pulse field gel electrophoresis (PFGE) is widely used for listeriosis surveillance. Although this technique is effective for epidemiology, the data among laboratories are inconsistent. We previously reported a method for Listeria monocytogenes subtyping combined with sequence analysis of partial iap and whole genome restriction fragment length polymorphism (RFLP) using XbaI, ClaI (BanIII) and PstI. However, distinguishing subtypes was challenging, because the output comprised complicated fragment patterns. In this study, we aimed to establish a simple genotyping method that does not depend on visual observation, rather it focuses on multi-locus sequence typing (MLST) using three genes, iap, sigB and actA. Sixty-eight strains of L. monocytogenes including EGD-e as a reference strain were investigated to ensure consistency with previous data on the genetic characterization. All strains were grouped into 29 types by both analyses. Although there are some differences in classification, major clades included the same strains. Simpson's indices of diversity (SID) by MLST and iap-RFLP-based typing were 0.967 (95% confidence interval [CI]: 0.955/0.978) and 0.967 (95% CI: 0.955/0.979), respectively. The discriminatory power of both methods can be considered almost identical. Compared with the results of 38 selected strains, the strains within the MLST clusters in this study coincided with those obtained using PFGE. Thus, the MLST strategy could help differentiate among L. monocytogenes isolates during epidemiological studies.

MR Imaging of Hippocampal Sulcus Remnant: Age-Related Differences

The hippocampal sulcus remnant (HSR) is often observed at the medial temporal lobe on MR images. In the present study, we made a retrospective assessment of the frequency and age-related differences in HSR in routine brain MR examinations of 1000 patients, 494 females and 506 males. Cases with one or several spots that were hypointense on T1-weighted and FLAIR images and hyperintense on T2-weighted images were defined as positive for HSR. Abnormal spots with the same intensity as cerebrospinal fluid were observed in 210 out of 506 males and in 193 out of 494 females. No significant sex-related differences were observed in the frequency of HSR. The HSR was seen more frequently with age in both males and females. Patients with hypertension had a significantly higher frequency of HSR.

The concentration of iodine in horse serum and its relationship with thyroxin concentration by geological difference

In this study, iodine and thyroxin (T4) concentrations in the serum of 69 horses were investigated. Higher iodine concentrations were obtained from the horses housed in Chiba Prefecture. In contrast, T4 concentrations of horses at Shizuoka Prefecture were higher than those of horses at Chiba Prefecture. There was a significant correlation (r = 0.643, P < 0.001) between the iodine and T4 concentrations of horses at Saitama and Shizuoka prefectures. Although a significant correlation (r = 0.794, P < 0.001) was also observed in the investigation of all horses at Chiba Prefecture, the distribution area of the data was separated from the data of horses housed in Saitama and Shizuoka prefectures. A higher iodine concentration in the environment is expected in the sampling area at Chiba Prefecture. Thus, it was suggested that the concentrations of iodine in the serum of horses are influenced by geological differences. It was thought that equine serum is a useful sample for monitoring.

Inflow Jet Patterns of Unruptured Cerebral Aneurysms Based on the Flow Velocity in the Parent Artery: Evaluation Using 4D Flow MRI

BACKGROUND AND PURPOSE

Inflow jet characteristics may be related to aneurysmal bleb formation and rupture. We investigated the visualization threshold on the basis of the flow velocity in the parent artery to classify the inflow jet patterns observed on 4D flow MR imaging.

MATERIALS AND METHODS

Fifty-seven unruptured aneurysms (24 bifurcation and 33 sidewall aneurysms) were subjected to 4D flow MR imaging to visualize inflow streamline bundles whose velocity exceeded visualization thresholds corresponding to 60%, 75%, and 90% of the maximum flow velocity in the parent artery. The shape of the streamline bundle was determined visually, and the inflow jet patterns were classified as concentrated, diffuse, neck-limited, and unvisualized.

RESULTS

At the 75% threshold, bifurcation aneurysms exhibited a concentrated inflow jet pattern at the highest rate. At this threshold, the inflow jets were concentrated in 13 aneurysms (group C, 22.8%), diffuse in 18 (group D, 31.6%), neck-limited in 11 (group N, 19.3%), and unvisualized in 15 (group U, 26.3%). In 16 (28.1%) of the 57 aneurysms, the inflow jet pattern was different at various thresholds. Most inflow parameters, including the maximum inflow velocity and rate, the inflow velocity ratio, and the inflow rate ratio, were significantly higher in groups C and D than in groups N and U.

CONCLUSIONS

The inflow jet pattern may depend on the threshold applied to visualize the inflow streamlines on 4D flow MR imaging. For the classification of the inflow jet patterns on 4D flow MR imaging, the 75% threshold may be optimal among the 3 thresholds corresponding to 60%, 75%, and 90% of the maximum flow velocity in the parent artery.

Biological index of environmental lead pollution: accumulation of lead in liver and kidney in mice

Lead (Pb) is known to be highly poisonous, and the acute poisoning of Cd causes the abdominal pains, vomiting, and shock. The digestive and nervous symptom is observed in the chronic lead poisoning. It was also known that the defect in hemoglobin synthesis by Pb produce anemia. The release of Pb into the environment presents a source of exposure for wild animals. In this study, we examined the utility of a new Pb-monitoring index in mice administered Pb. A solution containing 0.02, 0.2, 2, or 4 ppm lead chloride (PbCl2) was administered intraperitoneally to mice, and the Pb contents of the kidney and liver were determined at designated time points. The mean Pb content of both organs increased depending on the administered Pb dosage. Although the results of control was near the detection limits, the administration of 4 ppm in 4 weeks resulted in Pb levels of 260 mg ppm/wet weight and 110 ppm wet weight in the kidney and liver, respectively. However, there were no significant relationships among administered dose, duration of Pb treatment, and liver or kidney Pb content. Then, values in all mice administered control or 0.02 mg Pb were located inside the ellipse, representing the confidence area of the new index, and values in all mice administered more than 2 mg Pb were located outside the ellipse. These results confirm that animals exposed to high concentrations of Pb would be detected by this new index.

Parent artery curvature influences inflow zone location of unruptured sidewall internal carotid artery aneurysms

BACKGROUND AND PURPOSE

Future aneurysmal behaviors or treatment outcomes of cerebral aneurysms may be related to the hemodynamics around the inflow zone. Here we investigated the influence of parent artery curvature on the inflow zone location of unruptured sidewall internal carotid artery aneurysms.

MATERIALS AND METHODS

In 32 aneurysms, the inflow zone location was decided by 4D flow MR imaging, and the radius of the parent artery curvature was measured in 2D on an en face image of the section plane corresponding to the aneurysm orifice.

RESULTS

The inflow zone was on the distal neck in 10 (group 1, 31.3%), on the lateral side in 19 (group 2, 59.4%), and on the proximal neck in 3 (group 3, 9.4%) aneurysms. The radius in group 1 was significantly larger than that in group 2 (8.3 mm [4.5 mm] versus 4.5 mm [1.9 mm]; median [interquartile range]; P < .0001). All 7 aneurysms with a radius of >8.0 mm were in group 1. All 18 aneurysms with a radius of <6.0 mm were in group 2 or 3. In two group 3 aneurysms, the inflow zone was located in a part of the neck extending beyond the central axis of the parent artery.

CONCLUSIONS

The inflow zone locations of sidewall aneurysms can be influenced by the parent artery curvature evaluated in 2D on an en face image of the section plane corresponding to the aneurysm orifice.

Identification of the inflow zone of unruptured cerebral aneurysms: comparison of 4D flow MRI and 3D TOF MRA data

BACKGROUND AND PURPOSE

The hemodynamics of the inflow zone of cerebral aneurysms may be a key factor in coil compaction and recanalization after endovascular coil embolization. We performed 4D flow MR imaging in conjunction with 3D TOF MRA and compared their ability to identify the inflow zone of unruptured cerebral aneurysms.

MATERIALS AND METHODS

This series comprised 50 unruptured saccular cerebral aneurysms in 44 patients. Transluminal color-coded 3D MRA images were created by selecting the signal-intensity ranges on 3D TOF MRA images that corresponded with both the luminal margin and the putative inflow.

RESULTS

4D flow MR imaging demonstrated the inflow zone and yielded inflow velocity profiles for all 50 aneurysms. In 18 of 24 lateral-projection aneurysms (75%), the inflow zone was located distally on the aneurysmal neck. The maximum inflow velocity ranged from 285 to 922 mm/s. On 4D flow MR imaging and transluminal color-coded 3D MRA studies, the inflow zone of 32 aneurysms (64%) was at a similar location. In 91% of aneurysms whose neck section plane angle was <30° with respect to the imaging section direction on 3D TOF MRA, depiction of the inflow zone was similar on transluminal color-coded 3D MRA and 4D flow MR images.

CONCLUSIONS

4D flow MR imaging can demonstrate the inflow zone and provide inflow velocity profiles. In aneurysms whose angle of the neck-section plane is obtuse vis-a-vis the imaging section on 3D TOF MRA scans, transluminal color-coded 3D MRA may depict the inflow zone reliably.

Biofilm formation under different temperature conditions by a single genotype of persistent Listeria monocytogenes strains

Some Listeria monocytogenes strains, termed persistent strains, originate from the same processing plant and have the ability to survive and grow over extended periods of time at contamination sources. In order to evaluate biofilm formation by such persistent strains, we isolated the pathogen from chicken samples collected from the same retail shop in repeated visits over 6 months. Strains that were of serotype 1/2b and were assigned to the same genotype by multi-virulence-locus sequence typing analysis were isolated on repeated occasions from December 1997 to June 1998 and thus were defined as persistent strains. In the present study, biofilm formation by the persistent strains was evaluated using microplates at 30 and 37°C. The biofilm-forming capability was measured after cells attaching to the microplate well were stained with crystal violet. Comparison of biofilm formation at 30°C among the persistent strains showed that a significantly higher amount of the stain was obtained from the persistent strains isolated from December to March than from those isolated from April to June. However, no significant difference in biofilm formation at 30°C was observed between persistent and nonpersistent groups of L. monocytogenes strains. In contrast, biofilm formation at 37°C was consistent among the persistent strains, and they produced significantly more biofilm at 37°C than did the nonpersistent strains. The persistent strains were also found to change their biofilm-forming ability in a temperature-dependent manner, which may suggest that the persistent strains alter their biofilm formation in response to changing environmental factors.

The silicon concentration in cat urine and its relationship with other elements

To understand the effects of silicon (Si) in the urine with respect to the formation of urinary stones, the distribution of Si in urine was observed. Urine samples from cats with urolithiasis (n=10) and healthy cats (n=15) were used. The concentration of Si in the cats with urolithiasis was significantly higher (P<0.001). A significant correlation (P<0.05) was observed between the concentration of Si and those of other elements, such as calcium, magnesium, phosphorus, potassium and iron, only in the urine of the healthy cats. The distribution of elements in the urine differed between the cats with urolithiasis and the healthy cats. The Si concentration and its relationship with other elements were suggested to be useful biomarkers for urolithiasis in cats.

Interaction between titanium and cadmium in various guinea pig organs

Titanium (Ti) is used in many fields, while cadmium (Cd) is known to cause the itai-itai disease. In the present study, possible interactions between titanium and cadmium were investigated. Aorta, taenia coli, and liver were removed from male guinea pigs. Muscle tension was measured using intact aorta and taenia coli and using β-escin-permeabilized taenia coli in a physiological salt solution and a hyperpotassium solution containing Cd and/or Ti. Cellular Cd contents were determined using all tissues after washout with EDTA solution. Cadmium-induced relaxation in the hyperpotassium solution recovered significantly (P < 0.01) following Ti treatment in taenia coli, but not in the aorta. In β-escin-permeabilized taenia coli, the percentage recoveries after Cd treatment and after Ti plus Cd treatment were 67.3 ± 8.7 % (n = 4) and 87.7 ± 3.8 % (n = 4), respectively, compared with Ca-induced control contraction. Cellular Cd contents in taenia coli decreased significantly following treatment with Ti 10(-4) M. Although similar results were obtained using the aorta and the liver, there were no significant differences between the control and Ti 10(-5) M. High concentrations of Ti may reduce cellular Cd content.

Investigation of cadmium contamination using hair of the Japanese macaque, Macaca fuscata, from Shimokita Peninsula, Aomori Prefecture in Japan

The cadmium (Cd) contents in hair of macaques (n = 45, Macaca fuscata) living on the Shimokita Peninsula were investigated. The mean Cd contents in the hair of Japanese (n = 34, 5.01 μg/g) and macaques (3.05 μg/g) tendency to be higher than those of animals living other areas. The Cd contents of hair of wild macaques were significantly (p < 0.01) lower than that of humans, although three were no significant difference between Cd contents of humans and that of the macaque in captivity. The hair of the macaque was suggested as a useful sample for measurement of Cd contamination in the environment.

The distribution of several elements in cat urine and the relation between the content of elements and urolithiasis

The concentrations of elements in urine obtained from cats with urolithiasis were compared with those of healthy cats. The concentration of several elements, such as sodium (Na), phosphorus (P), sulfur (S), and potassium (K), in urine obtained from cats with urolithiasis was significantly higher than that of healthy cats. A significant correlation (p<0.01) was found between the concentration of magnesium (Mg) and that of other elements, such as P (r=0.8913), S (r=0.6817), and K (r=0.8391), in the urine obtained from healthy cats. A significant correlation (r=0.7422, p<0.05) was also obtained between the concentration of K and that of P in urine collected from cats with urolithiasis, but the slope of regression line was significantly different from that of the urine obtained from healthy cats. Other correlations observed in healthy cats were not obtained from cats with urolithiasis. However, a significant correlation between the concentration of magnesium (Mg) and that of calcium was obtained only from cats with urolithiasis. The results of the present study suggest that urinary concentrations of various elements in cats with urolithiasis are higher than those of healthy cats. Furthermore, the balance of elements in the urine of cats with urolithiasis was altered.

A basic study on the biological monitoring for vanadium-effects of vanadium on Vero cells and the evaluation of intracellular vanadium contents

A high concentration of vanadium (V) has toxic effects on human and animals and is one of environmental pollutants. In the present study, we have conducted a fundamental study using cultured Vero cells from monkey kidney for the future environmental monitoring. Orthovanadate (VAN), one of V compounds, of 10(-10) and 10(-8) M did not affect the cell growth although the higher concentration of above 10(-6) M VAN inhibited the cell growth accompanied with the decrease in cell numbers and morphological changes. Given that the washing method with ice-cold Li is also effective for determination of the cellular Na content, we used this method for the determination of the V content of the Vero cells. The V distributions in Vero cell; in the 10(-3) M VAN solution, extracellular and intracellular were obtained as 1:0.564:0.036 and 1:0.662:0.098 at 60 and 120 min after the treatment of VAN. The intracellular V content was 10% of the applied concentration of VAN. Consequently, it was suggested that V concentration of 10(-7) and 10(-6) M in the tissue and environment, respectively, might become the threshold concentration; a criterion of the environmental contamination when we carry out environmental monitoring.

Neurosarcoidosis: Radiologic Features in Five Patients

This paper describes the radiological features in five biopsy-confirmed cases of neurosarcoidosis. The imaging appearance of neurosarcoidosis is highly variable, making the diagnosis difficult on the basis of intracranial images alone. However, if there is evidence of spread along the pia mater, and meningeal mass formation with a lower intensity in the central area and higher intensity in the peripheral area on T2-weighted and FLAIR images, neurosarcoidosis can be considered.

Prevalence of Listeria monocytogenes in retailed meat in the Tokyo metropolitan area

This study was conducted to determine the prevalence of Listeria monocytogenes in retailed meats, comprising beef, chicken, and pork, in the Tokyo metropolitan area. A total of 379 samples of retailed meat were collected from 1998 to 2003, most of which were obtained by simultaneously purchasing the three classes of meat from a shop and then making another simultaneous purchase of meat from the same shop a few weeks later. The prevalence of L. monocytogenes was 28.0%, and the serotypes isolated were mainly 1/2a, 1/2b, 1/2c, and 4b. Comparison of the prevalence of each serotype among the classes of meat showed a predominant distribution of serotypes 1/2a, 1/2b, and 4b in chicken, while serotype 1/2c was dominant in pork. A total of nine cases considered to be due to persistence and/or cross-contamination were found. Most of the strains involved in persistence and/or cross-contamination were of serotypes 1/2c or 4b. These results suggest that contamination in retailed meat in Japan is at almost the same level as in other countries and that chicken has the highest potential as a source of contamination and infection. In addition, we suggest that the ecological niche of serotype 1/2c is distinct from those of 1/2a, 1/2b, and 4b, which may explain why human hosts have less opportunity to be exposed to serotype 1/2c and why there is a lower rate of isolation of this serotype from cases of human listeriosis.

Prevalence of herpes B virus genome in the trigeminal ganglia of seropositive cynomolgus macaques

Herpes B virus infection is almost asymptomatic in macaques (Macaca spp.), which are the natural hosts of this pathogen, but is the cause of high mortality in humans. Reactivation of the latent virus in the trigeminal ganglia (TG) results in the shedding of infectious particles into the oral mucosal membrane. Saliva contaminated with the reactivated virus from the ganglia of the natural host is considered to be important for viral transmission to humans and other monkeys. In the present study, we investigated the prevalence of the herpes B virus genome in the left and right TG of seropositive asymptomatic cynomolgus macaques. The latent virus genome was detected using a polymerase chain reaction and microplate hybridization assay. We found that the virus DNA was present in one or both TG of 12 of the 30 macaques (40%) tested, with the virus being detected from both TG in five of the 12 macaques and from a single TG in the remaining seven.

A new index for evaluation of cadmium pollution in birds and mammals

The degree of cadmium (Cd) contamination in wildlife is often used as an indicator in the environmental monitoring of Cd poisoning. However, previous studies have not clarified the correlation between levels in wildlife and levels in the environment by comparing levels among different species of animals; therefore, assessing the level of pollution in this manner is not considered a reliably accurate indicator of levels in the environment. The aim of this study was to establish a new indicator for the non-polluted warm-blooded animals, one that is not species-dependent, which will facilitate using different species for Cd monitoring. First, the previous publications regarding Cd contents in wildlife, 27 reports in which Cd contents were represented as arithmetic means and described for both kidney and liver were selected. A regression line (CSRL) between Cd contents of kidney and that of liver was obtained in a high correlation coefficient (R (2) = 0.943, P < 0.01). The mean values from land and waterfowl, terrestrial mammals, seabirds, marine mammals, and non-polluted humans were located on the line and aligned in order. CSRL might allow an accurate determination of whether an animal is polluted by Cd. CSRL was confirmed using well-established and widely recognized pollution models such as Itai-itai patients and Cd-exposed experimental animals. The Cd contents from these models were located in different positions relative to CSRL depending on the level of contamination. Thus, this new indicator determining the Cd-pollution status of animals would be useful for environmental monitoring.

Inhibitory mechanism of monensin on high K+-induced contraction in guniea-pig urinary bladder

In this study, we examined the inhibitory mechanism of monensin on high K+-induced contraction in guinea-pig urinary bladder. The relaxant effect of monensin (0.001 - 10 microM) was more potent than those of NaCN (100 microM - 1 mM) and forskolin (3 - 10 microM). Monensin (0.1 microM), NaCN (300 microM), or forskolin (10 microM) inhibited high K+-induced contraction without decreasing [Ca2+]i level. Monensin and NaCN remarkably decreased creatine phosphate and ATP contents. Monensin and NaCN inhibited high K+-induced increases in flavoprotein fluorescence, which is involved in mitochondrial respiration. Forskolin increased cAMP content but monensin did not. Monensin increased Na+ content at 10 microM but not at 0.1 microM that induced maximum relaxation. In the alpha-toxin-permeabilized muscle, forskolin significantly inhibited the Ca2+-induced contraction, but monensin did not affect it. These results suggest that the relaxation mechanism of monensin in smooth muscle of urinary bladder may be an inhibition of oxidative metabolism.

Characteristics of Listeria monocytogenes isolated from imported meat in Japan

The genomic structure of the iap region in Listeria monocytogenes (serovar 4b), isolated from chicken imported into Japan, was compared with those from Japanese strains. The isolate was similar to the Japanese strains in a comparatively new, rare group. Such strains might be imported from foreign countries.

Invasion assay of Listeria monocytogenes using Vero and Caco-2 cells

The invasion ability of Listeria monocytogenes into cultured cells has been used to evaluate its pathogenicity. In this study, invasive ability was investigated using Vero and Caco-2 cell lines. The form of invasion showed no morphological differences between both cell lines inoculated with L. monocytogenes L89-H2 or L96-23C1 strains when double fluorescence stained with rhodamine and FITC or with Giemsa staining. Recovery count and recovery rate of L. monocytogenes from Vero cells was related to the number of inoculated bacteria (2 x 10(5) to 2 x 10(7)/ml) in a bell-shape pattern, though the relationship was unclear in Caco-2 cells. Recovery rate of L. monocytogenes was higher in Vero cells than Caco-2 cells at a multiplicity of infection (MOI) 10, though the rates in both cells showed different stable stages over a considerably wide range of MOI. The recovery rate of all five L. monocytogenes strains from listeriosis patients was 15% at MOI 10 from infected Vero cells, while meat-derived strains showed variable rates regardless of the serovar. These results suggest that the Vero cell line is suitable for an invasion assay and that a recovery rate of 15% may be the critical limit for the expression of pathogenicity in the host.

Discrimination of Listeria monocytogenes contaminated commercial Japanese meats

Discrimination was attempted on 14 Listeria monocytogenes strains isolated from commercially available Japanese pork and chicken. Examination of the isolates was performed by restriction fragment length polymorphism (RFLP) analysis of the chromosomal DNA and amplified products and comparison of the nucleotide sequences of the amplified products. A polymorphism region containing the repeated sequences in the iap gene was amplified by the polymerase chain reaction (PCR). The genetic analyses could discriminate the 14 isolates in combination with traditional serotyping, and some strains isolated from different meats were confirmed to have a genetically close relationship. Genetic analyses used in the present study would be useful for the elucidation of the pathogen tracks from contaminated sources to humans and of the ecological niche in the food environment.

[Infectious disease of simian herpes B virus]

The epidemiology and the method of diagnosis were elucidated for simian herpes B virus (SHBV) infection. It is important that usefulness was demonstrated for the methods of DNA diagnosis having high sensitivity and specificity for SHBV and HSV-1, 2 types, and of detectable serological diagnosis for each specific antibody. The methods allowed the final diagnosis of the human infection due to the reactivation of latent SHBV and the HSV infection from human to monkey. These results would be able to become important and fundamental knowledge for the sero-epidemiological analysis of the infectious stile.

Analysis of the molecular evolution of Listeria monocytogenes isolated from Japanese meats and environment

Food contaminated by Listeria monocytogenes is a problem on a worldwide level because it is a serious food-borne pathogen. Although 3 evolutionary divisions have been reported for L. monocytogenes, the evolution of Japanese isolates has not yet been clarified. Thus, in order to determine the lineage of these Japanese isolates, we classified and conducted phylogenetic analysis of 407 bp (position 1116-1522) of the iap gene derived from 88 isolates from Japanese listeriosis patients, foods and environment. The isolates were classified into 18 types commonly accompanied by serotypes, and the types were divided into 3 lineages. Our results suggest that these Japanese isolates belong to the 3 lineages of L. monocytogenes isolated in other countries.

Thallium Contamination in Wild Ducks in Japan

Although thallium (Tl) is toxic to both humans and animals, there is little information on contamination in wildlife. In this study, Tl contents in wild ducks in Japan were determined. Contents of Tl in kidney and liver ranged from 0.42 to 119.61 and 0.10 to 33.94 microg/g dry weight, respectively. Significant correlations between Tl contents in kidney and liver were observed for all dabbling ducks except mallard (Anas platyrhynchos); similar correlations were not observed in diving ducks. Variation in Tl content was observed between sampling locations with the highest mean Tl content in the Eurasian wigeon (Anas penelope) collected in Ibaraki Prefecture.

Specific detection and identification of herpes B virus by a PCR-microplate hybridization assay

Herpes B virus DNA was specifically amplified by PCR, targeting the regions that did not cross-react with herpes simplex virus (HSV). The amplified products, which were shown to be highly genetic polymorphisms among herpes B virus isolates, were identified by microplate hybridization with probes generated by PCR. The products immobilized in microplate wells were hybridized with the biotin-labeled probes derived from the SMHV strain of herpes B virus. The amplified products derived from the SMHV and E2490 strains of herpes B virus were identified by microplate hybridization. PCR products amplified from the trigeminal ganglia of seropositive cynomolgus macaques were identified as herpes B virus DNA. The utility of the PCR-microplate hybridization assay for genetic detection and identification of the polymorphic region of herpes B virus was determined.

Contrast-enhanced MRA for investigation of cerebral arteriovenous malformations

We evaluated contrast-enhanced MRA (enhanced 3-D fast gradient-echo [efgre3d] with spectral inversion recovery) for identification of 15 intracranial arteriovenous malformations (AVMs) in 14 patients. Demonstration of the feeding arteries was classified as good for 16 examinations on maximum-intensity projections and multiprojection volume reconstruction images. The nidus was seen well in all patients. Definition of the draining veins was good or fair except for one poor result. Therapeutic effects were clearly demonstrated in three follow-up series. Contrast-enhanced MRA using efgre3d is useful for delineation of AVMs and for follow-up after treatment.

The distribution of molybdenum in the tissues of wild ducks

The Mo contents and the relations between Mo and Cu or Cr contents were investigated in the organs of Japanese wild ducks (spotbill duck, pintail, wigeon, scaup and tufted duck). The highest Mo content in kidney and liver of the dabbling ducks were more than 30 microg g(-1) dry weight (microg g(-1) d. wt.), though that of diving ducks were less than 11 microg g(-1) d. wt. The contents were lower in the ducks migrating within Japan, Eurasia and North America than those in the birds migrating between Japan and Eurasia. The contents of liver in all species were more than 50 and less than 5 microg g(-1) d. wt. for Cu and Cr, respectively. Significant correlations were found between Mo and both elements in pintail and scaup, and Mo and Cr in tufted duck. These results suggest that the contamination of wild ducks reflects the reproductive area, and not the collected area. Mo contents closely correlated with the Cu and/or Cr contaminations.

Swift and definite serotyping for isolated Listeria monocytogenes strains

The serotype is most important for molecular epidemiological analysis of Listeria monocytogenes (L.m.) contaminating marketed meats. An improvement on the traditional method was thus attempted in the present study because of the requirement of swift and definite serotyping. In the determination of O-antigen, definite judgement was allowed by an immediate cooling at 80 degrees C after autoclaving the bacteria. In the determination of H-antigen, use of a culture plate without Craigie's tube yielded the active bacteria only by single culture. The stable and clear agglutination in many samples was also obtained with a microplate using less antiserum. The availability was confirmed with 123 strains and the serovar 1/2b was dominant in the Japanese strains.

Cadmium contamination in wild birds as an indicator of environmental pollution

Cadmium (Cd) is an environmental pollutant that has serious toxicity in humans and animals and causes Itai-Itai disease. However, there is little available information on its contamination in wildlife as an indicator of environmental pollution. The Cd contents in the kidney and liver of 85 wild birds from 9 different prefectures in Japan were investigated. The ranges of the Cd contents in the kidney and liver in all birds were ND-174.4 and ND-21.2 microg g(-1) dry wt., respectively. The mean Cd contents were higher in the oil-contaminated birds than those in the non-contaminated ones. Furthermore, a strong correlation was obtained only between the Cd contents in the kidney and those in the liver of the oil-contaminated seabirds and not in the other non-contaminated ones. These results suggest that wild birds reflect the level of environmental contamination which should be monitored.

Contrast-enhanced MR angiography (enhanced 3-D fast gradient echo) for diagnosis of cerebral aneurysms

We evaluated contrast-enhanced MRA (enhanced 3-D fast gradient echo, EFGRE3D, with spectral IR) for the identification of unruptured cerebral aneurysms. We examined 22 aneurysms from 15 patients. In its ability to identify aneurysms, contrast-enhanced MRA was superior to 3-D-time of flight (3D-TOF) MRA in 4 instances, equal in 17, and inferior in 1. Contrast-enhanced MRA demonstrated thrombus formation more clearly and accurately than did 3D-TOF MRA. Contrast-enhanced MRA was performed in less than 1 min, and was found to be a useful method for the identification of intracranial aneurysms.

Simultaneous analysis for multiple heavy metals in contaminated biological samples

In the present study, the conditions of analysis by inductively coupled plasma-atomic emission spectrometry (ICP-AES) were investigated. Twenty-six elements (Mg: 25 ppm; Sc: 10 ppm; Ti: 50 ppm; others: 100 ppm) were used as the elements interfering with selected 24 wavelengths. Consequently, the background values in 19 elements were subjected to some influences. However, all of these effects disappeared at low concentrations--less than 1 ppm of interfering elements. Next, the values from the ordinary calibration method were compared with those from the standard addition method using several biological samples. There was a discrepancy in the results obtained from both methods because of the sample, and three patterns were observed. However, no discrepancy was observed in the values for the standard reference materials using both methods. There was no significant difference between the certified values of the standard reference materials and the obtained ones by ICP. Therefore, the analytical wavelengths and the methods in the present study were suggested to be useful for ICP-AES analysis for environmental and/or biological samples.

Contrast-enhanced fluid-attenuated inversion recovery MRI is useful to detect the CSF dissemination of glioblastoma

We present three cases of glioblastoma with CSF dissemination that contrast-enhanced fluid-attenuated inversion recovery MRI was sensitive enough to detect compared with contrast-enhanced T1-weighted MRI. An autopsy was performed on one patient, and its histologic findings proved the existence of CSF dissemination.

Importance of gap junction in gastric mucosal restitution from acid-induced injury

Evidence is accumulating that gap junctional intercellular communication (GJIC) plays an important role in the gastric mucosal defense system. This study was conducted to determine whether GJIC mediates a restitution process in gastric mucosa. Male Sprague-Dawley rats were fasted and anesthetized. Gastric injury was induced by luminal perfusion with 0.2N HCl for 10 minutes. Mucosal integrity was continuously monitored by measuring the clearance of chromium 51-labeled ethylenediaminetetraacetic acid, which was used for analysis of recovery from the injury. Perfusion with 0.25% octanol (OCT; inhibitor of GJIC) was started after acid injury to assess its effect on restitution. The effect of irsogladine (IG; activator of GJIC) was also tested. Gastric mucosal GJIC was immunohistochemically evaluated with monoclonal antibody gap junction protein (connexin 32). Recovery from acid-induced mucosal injury occurred rapidly when acid perfusion was discontinued (within about 60 minutes). OCT, which didn't cause any injury to normal gastric mucosa, significantly inhibited the restitution. IG reversed this inhibition in a dose-dependent manner. In an immunohistochemical study, OCT-induced damage of gap junction was demonstrated, but not after IG pre-treatment. These findings suggest that GJIC may play a critical role in restitution in rat gastric mucosa and that gap junction function may be one of the important factors for the mucosal defense system.

Effect of alpha-2 adrenoceptor antagonists on colonic function in rats

We studied the effect of alpha-2 adrenoceptor antagonists on colonic function stimulated by water-avoidance stress, 5-hydroxytryptamine (5-HT), bethanechol and castor oil by comparison with the effects of atropine and a 5-hydroxytryptamine 3 (5-HT3) receptor antagonist, ondansetron. Yohimbine, idazoxan and atropine, but not ondansetron, significantly inhibited water-avoidance stress-stimulated faecal excretion. Yohimbine and idazoxan inhibited neither 5-HT- nor bethanechol-stimulated faecal excretion. In contrast, atropine inhibited both 5-HT- and bethanechol-stimulated faecal excretion and ondansetron inhibited 5-HT-stimulated faecal excretion. Yohimbine did not inhibit the incidence of diarrhoea induced by castor oil, but idazoxan significantly inhibited diarrhoea observed during a 1-h period after the administration of castor oil. Both atropine and ondansetron inhibited diarrhoea during a 2-h period after the administration of castor oil. These findings suggest that alpha-2 adrenoceptor antagonists specifically inhibit colonic motor function stimulated by stress in rats.

Relationship between vanadate induced relaxation and vanadium content in guinea pig taenia coli

Abstract: Vanadate has been known to induce a transient increase in high K+ induced contraction, and also gradually relax the high K+ contraction itself in guinea pig taenia coli. The relationship between the rate of relaxation and ion content of Na+, K+, and V ion at the cellular level was investigated when vanadate was applied to contracted muscle. Tissue Na+ and V ion content increased linearly, depending on the time after vanadate treatment, reaching maximum levels of approximately 50 mM x kg(-1) and 0.25 mM x kg(-1) wet weight, respectively. There was a positive correlation between the V ion and Na+ contents, while there was a negative correlation between both ions and the relaxed rate of the high K+ induced contraction. The uptake of V ion was affected by the external K+ concentration, and the maximum rate of V ion uptake decreased to 40% in the presence of 90 mM external K+. These results suggest that a small amount of V ion was enough to inhibit the Na+ pump activity and muscle contraction in the high K+ solution.

Characterization of iap gene in Listeria monocytogenes strains isolated in Japan

Variation of the iap gene region (407bp) encoding an invasion-associated protein p60 was studied on 12 strains of Listeria monocytogenes of different origin in Japan. These 12 strains are known to have 2 types of serotype (1/2a and 4b) and have a diversity among the strains (Saito et al., 1998). The dye-primer cycle sequencing method was employed to determine the genomic structure, and the nucleotide sequences obtained were compared with those of reference strain SV 1/2a EGD. Differences found in the nucleotides were as follows; point mutations of 33 variations in 32 places; an insertion and 3 deletions of 3 bases; AAT position (po.) 1282-1283, and GCA po. 1307-1309, ACA po. 1412-1414, AAT po. 1439-1444, respectively. Different repeating numbers by 6 base unit, ACA AAT, were also found in the tandem repeat region (po. 1394-1423). Classification of 12 strains was attempted, then 8, 4 and 5 types were obtained from the point mutations, the insertions and deletions, and the repeating numbers, respectively. Consequently, 8 patterns were profiled regardless of each serotype. From these results, genomic structures were partially clarified in the iap gene 407bp of L. monocytogenes isolated in Japan. Then, the possibility of detailed epidemiology for L. monocytogenes infection using a combination of serotype and genome structure was suggested because of the previous polymorphism thought to be due to the nucleotide differences in the region.

Relationship between vanadate induced relaxation and vanadium content in guinea pig taenia coli

Vanadate has been known to induce a transient increase in high K+ induced contraction, and also gradually relax the high K+ contraction itself in guinea pig taenia coli. The relationship between the rate of relaxation and ion content of Na+, K+, and V ion at the cellular level was investigated when vanadate was applied to contracted muscle. Tissue Na+ and V ion content increased linearly, depending on the time after vanadate treatment, reaching maximum levels of approximately 50 mM·kg-1 and 0.25 mM·kg-1 wet weight, respectively. There was a positive correlation between the V ion and Na+ contents, while there was a negative correlattion between both ions and the relaxed rate of the high K+ induced contraction. The uptake of V ion was affected by the external K+ concentration, and the maximum rate of V ion uptake decreased to 40% in the presence of 90 mM external K+. These results suggest that a small amount of V ion was enough to inhibit the Na+ pump activity and muscle contraction in the high K+ solution.Key words: vanadate, high K+, relaxation, taenia coli, vanadium.