Biomedical subjects

A Kojima

Publications and source records attributed to A Kojima.

At least 19 recordsLinked to original sources

PubMed2006

Observation and control of transverse energy-transport barrier due to the formation of an energetic-electron layer with sheared ExB flow.

Off-axis electron-cyclotron heating in an axisymmetric barrier mirror produces a cylindrical layer with energetic electrons, which flow through the central cell and into the end region. The layer, producing a localized bumped ambipolar potential Phi(C), forms a strong shear of radial electric fields E(r) and peaked vorticity with the direction reversal of E(r)xB sheared flow near the Phi(C) peak. Intermittent vortexlike turbulent structures near the layer are suppressed in the central cell by this actively produced transverse energy-transport barrier; this results in T(e) and T(i) rises surrounded by the layer.

Journal Article↗

PubMed2006

Comparison of Campylobacter isolated from humans and food-producing animals in Japan.

AIMS: To compare the antimicrobial resistance, serotypes and flagellin gene types of Campylobacter isolated from humans and food-producing animals and thereby facilitate elucidation of the origin of Campylobacter causing human infection in Japan. METHODS AND RESULTS: The MIC values of ampicillin, dihydrostreptomycin, gentamicin, erythromycin, oxytetracycline, nalidixic acid and enrofloxacin for Campylobacter isolated from humans (134 isolates), cattle (38 isolates), pigs (69 isolates), layers (84 isolates) and broilers (51 isolates) were compared. The MIC(90) values of ampicillin for Campylobacter jejuni isolates from poultry were higher than those from humans and cattle. Campylobacter coli that was resistant to dihydrostreptomycin and erythromycin was observed at a higher frequency in humans and pigs than in poultry. The restriction fragment profiles of flaA of human, bovine and broiler isolates were analysed by clustering, and the isolates were classified into five clusters. Cluster I contained only human and bovine isolates. Clusters III, IV and V contained human, bovine and broiler isolates. CONCLUSIONS: Campylobacter isolates from humans included isolates that exhibited characteristics identical to those of the bovine, porcine and poultry isolates. SIGNIFICANCE AND IMPACT OF THE STUDY: In addition to poultry, cattle and pigs are believed to be sources of campylobacteriosis in Japan.

Ampicillin↗

PubMed2006

Drug resistance and random amplified polymorphic DNA analysis of Photobacterium damselae ssp. piscicida isolates from cultured Seriola (yellowtail, amberjack and kingfish) in Japan.

AIMS: To investigate the antimicrobial susceptibility and genetic characteristics of Photobacterium damselae ssp. piscicida isolates obtained from cultured Seriola in Japan. METHODS AND RESULTS: Minimal inhibitory concentrations of 14 antimicrobials for 74 isolates from Seriola in Japan in 2002 were determined. Isolates showed high frequencies of resistance to sulfamonomethoxine (SMMX) (97.3%), oxytetracycline (OTC) (77.0%), flumequine (FMQ) (77.0%), chloramphenicol (CP) (75.7%), kanamycin (KM) (63.5%) and oxolinic acid (OA) (62.0%), but low to ampicillin (ABPC) (2.8%). All isolates were susceptible to bicozamycin (BCM), fosfomycin (FOM) and florfenicol (FF). Of these isolates, 45 (60.8%) showed same resistance pattern (SMMX-OTC-FMQ-OA-CP-KM). In random amplified polymorphic DNA (RAPD) analysis, no difference was observed among our 74 field isolates and ATCC51736 isolated from Seriola in 1974 in Japan, but different from ATCC 17911 isolated from white perch in USA. CONCLUSIONS: FF, BCM, FOM and ABPC were useful antimicrobials for treating pseudotuberculosis. However, the frequency of multidrug resistance was high. RAPD analysis showed homogeneity of isolates from Seriola in Japan. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates that some antimicrobials were still useful for treating pseudotuberculosis and that P. damselae ssp. piscicida strains of same origin might have spread among Seriola in Japan since 1974.

Animals↗

PubMed2006

[Embolism of the lower limb caused by native aortic valve thrombosis].

Native aortic valve thrombosis is an uncommon event with heart valve disease, during cardiac catheterization, bacterial endocarditis, or a hypercoagulative state as in antiphospholipid antibody syndrome. We report a case of thrombus formation on a native aortic valve, which was found by the transesophageal echocardiography during thrombectomy of the lower limb. We supposed that the atheromatous plaque of aortic valve was related to thrombus formation.

Aortic Valve↗

PubMed2005

Polysaccharides as a template for silicate generated by sol-gel processes.

The polysaccharides, as established previously (Yu.A. Shchipunov, J. Colloid Interface Sci. 268 (2003) 68; Yu.A. Shchipunov, T.Yu. Karpenko, Langmuir 20 (2004) 3882), can manipulate the formation of hybrid silica nanocomposites by sol-gel processes. Here atomic force microscopy was applied to show whether carbohydrate macromolecules serve as a template for silicate. Mica was used as a substrate to adsorb polysaccharide. It was found that its surface is not neutral to the sol-gel processes, providing the silica precipitation. To hinder it, the mica was protected by a monomolecular film of arachidic acid with the help of a Langmuir-Blodgett technique. Hydrophobically modified cationic hydrohyethylcellulose was adsorbed from a diluted aqueous solution. It was demonstrated that the carbohydrate macromolecules located on the hydrophobic surface did promote silica precipitation, serving as a template.

Journal Article↗

PubMed2005

A national surveillance of Shiga toxin-producing Escherichia coli in food-producing animals in Japan.

To assess the public health risk, the prevalence and anti-microbial resistance of Shiga toxin-producing Escherichia coli (STEC) among food-producing animals were studied throughout Japan. Faecal samples were collected from healthy animals of 272 cattle, 179 pigs, and 158 broilers on 596 farms in all 47 Japanese prefectures. STEC were isolated from 62 (23%) cattle and 32 (14%) pig samples but from no chicken samples. Of the bovine isolates, 19 belonged to serotypes frequently implicated in human disease (O157:H7/non-motile (NM)/H not typeable, O26:NM/H11/H21/H not typeable, O113:H21, and O145:NM). The eae genes were observed in 37% of bovine isolates; among them one O145:NM and all four O157 isolates possessed eae-gamma1, and one O145:NM, one O103:H11, and all five O26 isolates possessed eae-beta1 gene. Among the swine isolates, stx2e were dominant, and serotypes frequently implicated in human diseases or eae-positive isolates were not observed. Bovine isolates showed less anti-microbial resistance, but six isolates of 26:NM/H11 and O145:NM were multi-resistant and may need careful monitoring. Swine isolates showed various resistance patterns; chloramphenicol resistance patterns were more common than in bovine isolates. This first national study of STEC in the Japanese veterinary field should aid our understanding of Japan's STEC status.

Animals↗

PubMed2005

Emergence of fluoroquinolone resistance in Campylobacter jejuni in chickens exposed to enrofloxacin treatment at the inherent dosage licensed in Japan.

The objective of the present study was to determine whether selection of fluoroquinolone resistance could be easily induced in Campylobacter jejuni-colonized chickens by treatment with enrofloxacin of representative fluoroquinolones at the inherent dosage licensed in Japan (50 ppm in drinking water for 3 days). In the case of isolates from chickens of study 1, an increase in the population of susceptible isolates appeared after the cessation of treatment and maintained throughout the experiments. On the contrary, our results of study 2 demonstrated that administration of enrofloxacin generated a rapid increase of fluoroquinolone resistance in C. jejuni showing the mutation of Asp-90-Asn in the gyrA gene. Present results indicate that the enrofloxacin treatment for broilers at the inherent dosage is able to select fluoroquinolone resistance in C. jejuni. We conclude that whatever enrofloxacin dosage is used, an emergence of fluoroquinolone resistant of C. jejuni occurs.

Animals↗

PubMed2005

Drug resistance and pulsed-field gel electrophoresis patterns of Lactococcus garvieae isolates from cultured Seriola (yellowtail, amberjack and kingfish) in Japan.

AIMS: To investigate the existing antimicrobial susceptibility and genetic characteristics of Lactococcus garvieae isolates from cultured Seriola in Japan. METHODS AND RESULTS: Minimum inhibitory concentrations (MICs) of 14 antimicrobial agents for 170 isolates were determined using the agar dilution method. Seventy-five isolates (44.1%) were simultaneously resistant to erythromycin (EM) (MIC>or=2 microg ml-1), lincomycin (LCM) (MIC>or=128 microg ml-1) and oxytetracycline (OTC) (MIC>or=4 microg ml-1). Resistance to EM was grouped as intermediate- and high-level resistant by MIC values. All resistant isolates possessed ermB and tet(S) genes. The number of different bands between pulsed-field gel electrophoresis patterns of 25 isolates and two ATCC strains (isolated in 1974), determined using two enzymes (ApaI and SmaI), did not exceed 3. CONCLUSIONS: The present resistance pattern observed with ermB and tet(S) is similar to that observed in previous reports. Moreover, the genetic characteristics of L. garvieae isolates from a wide area in Japan in 2002 and ATCC strains were closely related. SIGNIFICANCE AND IMPACT OF THE STUDY: This study suggests that EM-, LCM- and OTC-resistant isolates have been present for 15 years and that L. garvieae strains with same origin have spread among Seriola spp. in Japan since 1974.

Animals↗

PubMed2005

A comparison of the inflammatory response and the recovery of bowel function between trans- and extraperitoneal approaches of abdominal aortic aneurysmectomy.

AIM: To determine whether surgical stress is less with transperitoneal or extraperitoneal abdominal aortic aneurysmectomy, blood concentrations of inflammatory cytokines and other inflammatory markers with recovery of bowel function were examined. METHODS: Patients who underwent abdominal aortic aneurysmectomy electively via the transperitoneal (T-group; n=15) or the extraperitoneal approach (E-group; n=17) were evaluated. Inflammatory cytokines (interleukin[IL]) IL-6, IL-8, C-reactive protein concentrations, and systemic inflammatory response syndrome score were determined before operation and after operation on days (POD) 1, 3, 7, and 14. Recovery of bowel function was estimated by the time taken for resumption of bowel movement and oral intake, and by the volume of fluid collection from the nasogastric tube. RESULTS: Cytokine (IL-8) concentrations were higher in the T-group than the E-group with significant difference on POD 7 (4.8+/-0.5 versus 3.4+/-0.2 pg/mL, respectively; P=0.02). Recovery of bowel function and oral intake were earlier, and the volume of fluid collection from the nasogastric tube was smaller in the E-group than the T-group significantly. CONCLUSIONS: Early recovery of bowel function and low concentration of inflammatory cytokines suggest that the extraperitoneal approach to the abdominal aorta is less stressful to the transperitoneal approach. Postoperative inflammatory response may mainly depend on damage of the bowel in the operation of the abdominal aortic aneurysm.

Adult↗

PubMed2004

Heat-stress enhances proliferative potential in rat soleus muscle.

The effects of heat-stress on proliferative potential in vivo were studied in rat skeletal muscle. Male Wistar rats (7-weeks-old) were divided into two groups: control (n=24) and heat-stressed (n=24). Rats in the experimental group were exposed to environmental heat-stress (41 degrees C for 60 min) in a heat chamber without anesthesia. The soleus muscles were dissected 1, 7, and 14 days after the heat exposure. The wet and dry weights of soleus muscle relative to body weight in the heat-stressed group were significantly higher than controls 7 days after the exposure (10.1% and 17.5%, respectively, p <0.05). The distribution of 5-bromo-2'-deoxyuridine and proliferating cell nuclear antigen-positive nuclei, that are the indicators for the cell proliferation, were increased by 2.2 and 5.1 times, respectively 1 day after heating (p <0.05). The expressions of heat shock protein 72 (58.0%) and phosphorylated p70S6 kinase (52.3%) were increased 1 day following heat exposure (p <0.05). These results suggest that heat-stress could promote the cell proliferation and induce muscular hypertrophy.

Adaptation, Physiological↗

PubMed2004

Heat stress facilitates the recovery of atrophied soleus muscle in rat.

Effects of heat stress on the recovery of atrophied soleus muscle were studied in rats. Ten-week-old male Wistar rats were randomly divided into cage control (CC) and 5-day hindlimb suspension group (HS). The half of the rats in group HS was exposed to heat stress (41 degrees C for 60 min) in an incubator immediately after the hindlimb suspension (HS-H) and the other group of rats was not heat stressed (HS-C) prior to 10 days of ambulation recovery. One group of cage control rats (CH) was also exposed to heat similarly. The soleus muscles were dissected at four time points, i.e., immediately after the suspension (or heat stress), and 3, 5, and 10 days after the recovery (n=8 per group at each time point). The absolute wet weight and water and protein content of whole soleus muscle in group HS-C were approximately 36, 27, and 8 mg less than CC (p <0.05). Thus, the percentage contribution of water and protein loss to the decrease in muscle weight was 75 and 22%, respectively. Although water content, as well as muscle weight, was elevated within 3 days, the increase of protein was delayed. Heat exposure prior to recovery accelerated the increase in protein content even in the control group. These phenomena were closely associated with 72-kD heat shock protein (HSP72) content. It is suggested that heat stress applied at the end of hindlimb unloading facilitated the recovery of atrophied soleus muscle of rat, through possibly HSP72-related events of protein metabolism. The data also indicated that the combination of heat and mechanical stress evoked larger and long lasting HSP72 response than does heat or mechanical stress alone.

Adaptation, Physiological↗

PubMed2004

Adverse effects of energy restriction on changes in immunoglobulins and complements during weight reduction in judoists.

AIM: A preliminary study to investigate the combined effects of dietary restriction and weight reduction through exercise on markers of immune function in college judoists before and after a single competition. METHODS: Forty-nine judoists participated in the study. Thirty-eight athletes combined exercise and dietary restriction (WR group), and 11 athletes did not require dietary restriction (EX group). Changes in anthropometric parameters, energy intake, concentrations of serum immunoglobulins and complements, and white blood cell counts were assessed at 4 time points: 20 days (pre-values), 4 days and 1 day before the competition, and 7 days after the competition. RESULTS: Compared with pre-values, the WR group exhibited significant decreases in body weight (-2.8 kg at 1 day before) and fat free mass (-1.7 kg at 1 day before); there were no changes in these variables in the EX group. The WR group exhibited significant decreases in IgG, IgM and C3 at 7 days after the competition (all p<0.01). In the EX group, significant decreases in IgM and C3 (both p<0.05) were observed at 7 days after the competition, though to a lesser degree than in the WR group. CONCLUSIONS: Energy restriction seemed to exacerbate alterations in immune markers such as immunoglobulin and complement induced by vigorous exercise at 7 days after a competition. Although the changed values were still within normal limits, we hypothesize that the potential cumulative effect of these changes over many competitions in 1 year might well induce abnormal levels with a possibly harmful clinical effect on judoists.

Adult↗

PubMed2003

Human papillomaviruses in the normal oral cavity of children in Japan.

The purpose of this study was to determine the frequency of human papillomavirus (HPV) infections in the normal oral cavity of children in Japan. Oral squamous cell specimens were collected from 77 children (44 boys and 33 girls), aged 3 and 5 years. Extracted DNA was evaluated for HPV infections by polymerase chain reaction (PCR) methods, using consensus primers for the L1 region, specific primers, and direct DNA sequencing analysis. Thirty-seven of 77 specimens (48.1%) were positive for HPV DNA. Positive rates of boys and girls in all specimens were 28.3 (22/77) and 19.5 (15/77)%, respectively. The positive rate in 3-year-old children was 45.2 (14/31)%, and positive rates in boys and girls were 52.6 (10/19) and 33.3 (4/12)%, respectively. The positive rate in 5-year-old children was 50.0 (23/46)%, and positive rates in boys and girls were 48.0 (12/25) and 52.4 (11/21)%, respectively. HPV types were determined by specific PCR and direct DNA sequencing analysis. Frequent HPV types in the specimens of all children were HPV-16 (11/37; 29.7%),-1 (6/37; 16.2%),-2 (6/37; 16.2%),-75 (6/37; 16.2%). The results of the present investigation indicate that many HPVs, including HPV-16 (a high-risk type for cancer), are present in the oral cavity of 3- and 5-year-old children. It is suggested, therefore, that the oral cavity is already a reservoir of HPVs in childhood where later HPV-associated diseases, such as oral cancer and other oral lesions, may develop.

Age Distribution↗

PubMed2003

Explanations for the smoking paradox in Japan.

The prevalence of cigarette smoking among Japanese men has been consistently high compared with Western males over the past 30 years. However, during the same period, the incidence of and mortality rates for lung cancer have consistently been lower in Japan than in Western countries ('Japanese smoking paradox'). The odds ratio/relative risk of cigarette smoking for lung cancer mortality/incidence relative to the same number of cigarettes smoked per capita in Japan, were apparently lower than those in Western countries. This must be the cause driving the 'Japanese smoking paradox'. Furthermore, low carcinogenic ingredients in Japanese cigarettes and a congenitally-related resistance to smoking-related lung carcinogenesis emerged as the main factors which have brought the 'Japanese smoking paradox'.

Adolescent↗

PubMed2003

Survey of nasal colonization by, and assessment of a novel multiplex PCR method for detection of biofilm-forming methicillin-resistant staphylococci in healthy medical students.

We surveyed the prevalence of nasal colonization by biofilm-forming methicillin-resistant staphylococci in healthy medical students, who had never had contact with patients, using polymerase chain reaction (PCR) to detect themec A gene, production of penicillin-binding protein 2' (PBP2'), and quantitative assay of biofilm formation on polystyrene. Anterior nasal swabs from 90 students were cultured on mannitol salt and oxacillin salt screening agar plates. In total, 231 staphylococcal isolates belonging to 10 species from 88 students were identified, of which 139 from 77 (88%) students were Staphylococcus epidermidis. The overall prevalences of methicillin-resistant and biofilm-forming staphylococci were 48% (43 of 90) and 59% (53 of 90) for the medical students, respectively. In total 30 (33%) students carried biofilm-forming methicillin-resistant staphylococci in the nares, all of which were identified as S. epidermidis. For rapid detection of biofilm-forming methicillin-resistant S. epidermidis (MRSE), we devised a novel multiplex PCR method to assess a total of 243 staphylococcal isolates, including the 231 isolates from the students. The multiplex PCR assay used six primers to amplify atl E and ica ADB, which are responsible for the biofilm formation ofS. epidermidis, and mec A genes. The multiplex PCR assay revealed that 68 (96%) isolates were detectable in 71 biofilm-forming MRSE isolates, which corresponded to 93% (28 of 30) of biofilm-forming MRSE carriers. Surveillance of nasal colonization with biofilm-forming MRSE using this multiplex PCR in healthcare workers and patients, might provide useful information for the establishment of infection control procedures toward biofilm-forming MRSE.

Adult↗

PubMed2003

Patchy atrophy and lacquer cracks predispose to the development of choroidal neovascularisation in pathological myopia.

AIMS: To determine the incidence and predisposing findings for choroidal neovascularisation (CNV) in a large series of highly myopic patients. METHODS: The medical records of 218 consecutive patients (325 eyes) with myopic fundus changes in the macula were reviewed. The incidence of CNV during a follow up of at least 3 years of highly myopic patients and identification of predisposing findings for the development of myopic CNV were examined. RESULTS: Among 325 highly myopic eyes examined, 33 eyes (10.2%) developed myopic CNV. The incidence was higher (34.8%) among the fellow eyes of patients with pre-existing CNV than among eyes of patients without pre-existing CNV (6.1%). CNV developed in 3.7% with diffuse chorioretinal atrophy, in 20.0% with patchy atrophy, and in 29.4% with lacquer cracks. CONCLUSION: Approximately one in 10 highly myopic eyes developed myopic CNV in average 130.2 months. Patchy atrophy and lacquer cracks were shown to be important predisposing findings for CNV development.

Adolescent↗

PubMed2003

Peripapillary crescent enlargement in highly myopic eyes evaluated by fluorescein and indocyanine green angiography.

AIMS: To evaluate angiographic features of myopic crescents using fluorescein angiography (FA) and indocyanine green angiography (IA). METHODS: FA and IA angiograms of 88 highly myopic eyes (47 consecutive patients) were reviewed. The follow up period ranged from 5-28 years. RESULTS: FA revealed two zones of the myopic crescent: a consistently hypofluorescent inner zone and an outer zone with delayed choroidal filling. IA revealed dislocation of the Zinn-Haller ring to the border between the two zones. Myopic crescent enlargement occurred in 68.1%. Only the outer zone increased significantly in most of the eyes with enlarged crescents. CONCLUSIONS: The inner zone might develop as a result of mechanical stretching, and the outer zone might be the result a secondary circulatory disturbance and mechanical stretching.

Adolescent↗

PubMed2003

Transmission of alien chromosomes from selfed progenies of a complete set of Allium monosomic additions: the development of a reliable method for the maintenance of a monosomic addition set.

Selfed progeny of a complete set of Allium fistulosum - Allium cepa monosomic addition lines (2n = 2x + 1 = 17, FF+1A-FF+8A) were produced to examine the transmission rates of respective alien chromosomes. All eight types of the selfed monosomic additions set germinable seeds. The numbers of chromosomes (2n) in the seedlings were 16, 17, or 18. The eight extra chromosomes varied in transmission rate (%) from 9 (FF+2A) to 49 (FF+8A). The complete set of monosomic additions was reproduced successfully by self-pollination. A reliable way to maintain a set of Allium monosomic additions was developed using a combination of two crossing methods, selfing and female transmission. FF+8A produced two seedlings with 18 chromosomes. Cytogenetical analyses, including GISH, showed that the seedlings were disomic addition plants carrying two entire homologous chromosomes from A. cepa in an integral diploid background of A. fistulosum. Flow cytometry analysis showed that a double dose of the alien 8A chromosome caused fluorescence intensity values spurring in DNA content, and isozyme analysis showed increased glutamate dehydrogenase activity at the gene locus Gdh-1.

Allium↗