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Biomedical subjects

K Maejima

Publications and source records attributed to K Maejima.

At least 55 records · Page 3Linked to original sources
PubMed1990

[An evaluation method for hematological and clinico-biochemical values in aged F 344 rats on chronic toxicity tests such as long-term inhalation studies on the effects of diesel exhaust].

To determine the chronic toxicity of diesel exhaust, 2,150 F 344 rats were made to inhale various dilutions of exhaust under specific pathogen-free conditions for 16 hours a day, 6 days a week, for 30 months. Ten experimental groups, each with 120 male and 95 female 5 week-old rats, were set up and 14 males and 9 females were usually sacrificed for measurement of the 51 hematological and clinico-biochemical parameters at 7, 13, 19, and 25 months of age, respectively. These parameters were also examined in all surviving rats after 30 months of exhaust inhalation. In this experiment, no remarkable change in any of the parameters was observed in the periodic examinations. Therefore, tendencies of change in parameters were examined by comparing histograms for control and experimental groups. For the reference histograms, we used the values obtained from 144 males and 116 females aged 13-31 months. The first histogram was based on data from 1,352 rats, and the range from the minimum to the maximum value was divided into eight parts. When almost all the values were centered on a peak in the first histogram, this peak was divided into a further eight parts in the second histogram. Histogram evaluation clarified the differences between the control and experimental groups better than general statistical methods such as Student's t-test.

Administration, Inhalation↗
PubMed1990

[Heat and ozone resistance of Bacillus spores isolated from laboratory animals].

Heat resistance of free-spores of 78 Bacillus strains isolated from laboratory animals was examined. Spores of 41 out of 78 strains survived for 320 minutes at 70 degrees C, 27 for 160 min, at 100 degrees C, only one for 20 min. at 110 degrees C by autoclaving, and none for 5 min. at 120 degrees C. D-values at 100 degrees C of 9 strains determined were between 5.03 and 30.06 min. Spores of 9 strains from stock cultures were exposed to ozone gas at various conditions. Ozone resistance of spores was closely dependent upon relative humidity. D-values of the spores tested by treatment with 200 ppm ozone at 60% RH were over 200 min., especially over 1,000 min. in 4 strains, indicating that exposure to ozone at a moderate humidity for 6 hours could not sterilize Bacillus spores. At 90% RH, however, treatment with 200 ppm ozone for 6 hr. might be effective for a routine sterilization in laboratory animal facilities.

Animals↗
PubMed1990

Wear of artificial denture teeth by use of toothbrushes. Part 1: Abrasive wear of anterior teeth.

High-strength denture teeth (HS teeth) were developed in order to improve the hardness and wear resistance of conventional plastic denture teeth (PL teeth), while retaining their feature of easy occlusal adjustment. The objective of this study was to evaluate the abrasive wear resistance of HS teeth. We conducted wear tests and measured surface roughness using six types of anterior artificial teeth, i.e., three types of HS teeth and three types of PL teeth, the latter serving as the control. The results of the toothbrush abrasion test revealed that the HS teeth had about 5 times greater wear resistance than the PL teeth. It was also found that the type of artificial teeth and the number of abrasive wear-testing strokes had a significant (P less than 0.05) influence on the surface roughness of artificial teeth.

Dental Stress Analysis↗
PubMed1988

[Serological survey of feline leukemia virus infection and the outcome of antibody-positive cats].

A serological survey was carried out to examine the presence of antibodies against feline leukemia virus (FeLV) and feline oncornavirus-associated cell membrane antigen (FOCMA) in 208 cat sera collected at Teikyo University School of Medicine. Seven cats (3.4%) were positive for FeLV antibodies by enzyme-linked immunosorbent assay whereas no cat was positive for FOCMA antibody by indirect membrane immunofluorescent test. Anemia, leukemia and/or lymphoma formation were not observed in these FeLV antibody-positive cats. But among these seven cats, three were positive for toxoplasma antibodies. One of them was also positive for Chlamydia psittaci antibody and it died in pneumonia. Among the four toxoplasma antibody negative cats, one was died in eosinophilic granuloma. Furthermore, two of three cats, which were used for experiments, had cold and took therapy.

Animals↗
PubMed1987

[Method of separating mouse platelets by discontinuous sucrose-gradient centrifugation].

A discontinuous sucrose gradient was employed in the separation of mouse blood platelets using a modified Booyse method. The platelets of male CD-1 mice aged 8 to 12 weeks were divided into five distinct populations (A, B, C, D & E). Distribution of light to heavy platelets patterns in 10 normal CD-1 mice was demonstrable at; A (S.G. 1.188), as 14.8 +/- 5.6%; B (S.G. 1.199), 44.0 +/- 4.6%; C (S.G. 1.207), 24.1 +/- 3.4%; D (S.G. 1.214), 13.0 +/- 3.6%; and E (S.G. 1.221), 4.0 +/- 1.5%.

Animals↗
PubMed1985

Effect of oral antibiotics and bacterial overgrowth on the translocation of the GI tract microflora in burned rats.

Infections in burned patients have generally been considered to arise from exogenous organisms. Consequently, the therapy of burned patients has emphasized the use of infection control policies and topical antimicrobial agents to reduce bacterial colonization. Even though enteric bacteria are frequently found in the burn wound little attention has been paid to the patient's own GI tract microflora as a potential source of organisms colonizing the burn wound. The current experiments were carried out to determine if the bacteria present in the GI tract of healthy animals would penetrate (translocate) through the GI mucosa and spread to visceral organs after a moderate or major thermal injury. The results of these experiments indicated that bacteria can translocate across the wall of the GI tract and survive in the mesenteric lymph nodes in healthy rats. Furthermore, when the GI tract microflora is altered, either due to bacterial overgrowth or under the influence of oral antibiotic therapy, not only will bacteria translocate to the mesenteric lymph nodes but bacteria will also spread to other visceral organs. The results of these experiments support the hypothesis that the GI tract can serve as a reservoir for nosocomial infections in the burned patient, since bacteria can translocate across the mucosal barrier of the GI tract after thermal injury and survive in visceral organs before colonization of the burn wound occurs.

Administration, Oral↗
PubMed1985

[An outbreak of staphylococcal dermatitis in laboratory mice].

An epizootic of dermatitis with erosion, ulcer and crust broke out in an experimental colony of JCL-ICR mouse over a period from December 1975 to June 1976. The disease was detected in 592 of a total of 1831 mice of 3-24 months old, especially in males of 7-24 months old (517/821). At the beginning of December 1975, only a few males of 12 months old were found to have the lesion on the back skin, and thereafter the dermatitis prevailed gradually among the mice. Histopathologic examinations showed the loss of the epidermis, necrosis and/or collapse of the corium, accumulation of serous exudate with neutrophilic cell infiltration and a few cocci scattered on the surface. In chronic cases, fibrous granulation tissues with neutrophilic cell infiltration were formed in the corium. Staphylococcus aureus was isolated in pure culture from the skin lesions in all of the mice examined. Skin disease similar to that of the field case was reproduced in mice inoculated subcutaneously with 10(7) viable organisms of the fresh isolate. By giving chlortetracycline in drinking water for 7 days, treatment of the affected mice was efficacious in mild cases, but not in severe cases.

Aging↗
PubMed1985

[Biological properties, phage typing and antimicrobial susceptibility of Staphylococcus aureus isolated from dermatitis in laboratory mice].

The characteristics of 167 isolates of S. aureus from 106 mice suffering dermatitis were examined. All 167 isolates coagulated both rabbit and human plasmas and 161 of them also coagulated bovine plasma. All the isolates produced heat-stable and heat-labile DNase, phosphatase and yellow pigment, reduced nitrate, hydrolysed egg yolk, Tween 80, and hippurate, and grew on crystal violet agar in colonies of the negative type C and on medium with 10% NaCl. The majority of them produced fibrinolysin, protease and acetoin. Fifty-three percent were gelatinase positive. In hemolysis tests, 25, 57 and 45 isolates showed alpha-, beta-, alpha beta-hemolysis, respectively. Forty isolates did not produce hemolysins in the rabbit and sheep blood agar. All of 75 isolates tested produced acid from fructose, galactose, glucose, glycerol and mannose, but did not from arabinose, dextrin, inulin, raffinose, salicin, sorbitol and xylose. Most of these isolates produced acid from lactose, mannitol, sucrose and trehalose. All of the 75 isolates were highly sensitive to penicillin, methylphenylisoxazolyl penicillin, erythromycin, spiramycin, lincomycin, chloramphenicol, tetracycline, kanamycin, gentamicin and cephaloridine, but were resistant to sulfisoxazole. With phages of human set, all 167 isolates were typable at 100 X RTD. All but one of the typable isolates belonged to mixed lytic groups. These were I + III (35 isolates), I + M (1), I + III + M (124) and I + II + III + M (6), with long phage patterns. When the 167 isolates were biotyped as described by Hájek and Marsálek [7, 8], 5 belonged to biotype A, 1 to biotype B and 60 to biotype C.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Promotion by burn stress of the translocation of bacteria from the gastrointestinal tracts of mice.

A mouse burn model was established to test the effect of nonlethal thermal injury on the translocation of indigenous bacteria from the gastrointestinal (GI) tract to other organs. Specific pathogen-free (SPF) mice were given 15% or 30% total body surface area burns, and the mesenteric lymph nodes (MLNs), spleens, livers, blood, and peritoneal cavities were cultured for translocated bacteria at various time intervals. No viable aerobic, facultatively anaerobic, or strictly anaerobic bacteria of the indigenous flora grew in cultures from the MLNs of these mice. Consequently, SPF mice were antibiotic decontaminated and then colonized with Escherichia coli to develop a model in which E coli maintains abnormally high cecal population levels and translocates continuously to the MLN. These mice received 15% or 30% thermal burns four days after colonization with E coli. The incidence of bacterial translocation and the numbers of E coli translocating to the MLN, spleen, liver, blood, and peritoneal cavity increased with increasing burn area compared with controls. Mice receiving 15% burns could not clear intravenously challenged E coli from their bloodstream, MLN, or liver. Thus, burn stress promotes the translocation of bacteria from the GI tract to other organs to cause bacteremia.

Animals↗
PubMed1984

Bacterial translocation from the gastrointestinal tracts of rats receiving thermal injury.

Rats receiving nonlethal thermal burns over 20 or 40% of their total body surface area were tested at various intervals for the translocation of indigenous bacteria from their gastrointestinal tracts to their mesenteric lymph nodes, peritoneal cavities, and bloodstreams. No indigenous bacteria were cultured from these organs of control rats or from rats receiving 20% burns. However, 44% of the rats receiving 40% burns exhibited viable Escherichia coli, Proteus mirabilis, Staphylococcus sp. and Clostridium sp. in their mesenteric lymph nodes 2 days after thermal injury. Bacterial translocation after burn stress also was tested in antibiotic-decontaminated rats monoassociated with E. coli. E. coli attained population levels in these animals of 10(8) to 10(9) per g cecum. E. coli translocated to 100% of the mesenteric lymph nodes of both the control and 40% burned rats. However, E. coli translocated at a greater incidence to the spleens, livers, and peritoneal cavities of the burned rats compared with translocation to these organs in control rats. The numbers of E. coli translocating to the mesenteric lymph nodes, spleens, and livers also were greater in the 40% burned rats than in control rats. By 14 days after thermal injury, the rats were able to clear E. coli from their spleens and livers, and the infection remained localized in the mesenteric lymph nodes. These results support the concept that the indigenous gastrointestinal flora or exogenous organisms colonizing the gastrointestinal tract are potential sources of septicemia after thermal injury.

Animals↗
PubMed1984

Assessment of mouse strain on bacterial translocation from the gastrointestinal tract.

The translocation of indigenous bacteria from the gastrointestinal tract to the mesenteric lymphnodes was compared in ten strains of mice. Indigenous Escherichia coli were cultured from the mesenteric lymphnodes of only two of the six mouse strains examined. Thus, spontaneous translocation of indigenous enteric bacteria across the intestinal barrier did not occur to any significant extent in any of the mouse strains examined. Since bacterial overgrowth in the gastrointestinal tract promotes bacterial translocation, bacterial translocation was tested in ten mouse strains including B10 series after antibiotic-decontaminated and subsequent colonization with streptomycin-resistant E. coli C25. E. coli C25 populated the ceca of the mice at levels of 10(8) to 10(9) per gram and translocated to 90-100% of the mesenteric lymphnodes with mean of 10(1.13) to 10(1.86) per mesenteric lymphnode. However, there were no significant differences between mouse strains as to the translocation incidence or the numbers of viable E. coli C25 per mesenteric lymphnode. Thus, genetic differences between mouse strains did not influence bacterial translocation from the gastrointestinal tract to the mesenteric lymphnodes.

Animals↗
PubMed1984

Drug resistance in Streptococcus faecalis, Streptococcus faecium and Staphylococcus epidermidis isolated from laboratory animals.

A total of 1,278 strains of Streptococcus faecalis, 688 of Str. faecium and 796 of Staphylococcus epidermidis were collected from laboratory animals of 20 colonies in 1980, and tested for their resistance to 20 drugs. Thirteen percent of Str. faecalis, 12% of Str. faecium and 25% of Staph. epidermidis were drug resistant. Multiple drug resistant organisms were frequently detected in laboratory animal colonies where antibiotic treatment had been undertaken. TC-resistant streptococci and EM-resistant Staph. epidermidis were distributed in about half of the colonies regardless of the history of antibiotic usage.

Animals↗
PubMed1983

[The antibacterial activity of new cephem antibiotics against clinical isolates. A comparison of the antibacterial activity of cefotaxime with 6 other antibiotics].

During the period from May through July 1981, a comparative study was carried out on the antibacterial activities of cefotaxime (CTX) and ceftizoxime (CZX), cefoperazone (CPZ), latamoxef (LMOX), cefotiam (CTM), cefmetazole (CMZ) and cefazolin (CEZ). CTX and these other cephem antibiotics were tested against fresh clinical isolates which had been obtained from clinical materials by the laboratories of 14 participating medical institutions. 1. The clinical isolates were obtained from various clinical materials in the following decreasing order: urine, sputum and pus/discharge; 85.7% of the isolates came from these materials. 2. Concerning the sources of each species of clinical isolates, it was found that P. aeruginosa was isolated from the greatest number -9- of different clinical materials. This was followed by E. coli and E. cloacae, each isolated from 8 different clinical materials, and C. freundii and E. aerogenes, each found in 7 different clinical materials. 3. In relation to S. pyogenes, S. agalactiae and S. pneumoniae, CTX showed the best antibacterial activity; the second most potent antibiotic was CZX. CMZ and LMOX were found to show relatively high MIC values for those species. Against S. aureus, CEZ showed the best antibacterial activity, but 3 resistant strains had MICs of greater than 100 micrograms/ml. 4. With regard to Gram-negative bacteria, CTX and CZX showed the best antibacterial activities for all of the species, except for P. aeruginosa. These were followed, in order, by LMOX and CPZ. Compared with these 4 antibiotics, CTM, CMZ and CEZ were found to have inferior antibacterial activities against these bacteria. In relation to P. aeruginosa, the peak of the MIC distribution for CPZ was 6.25 micrograms/ml, and this was the best antibacterial activity detected with the various antibiotics tested. This was followed by CTX (25 micrograms/ml) LMOX (25 micrograms/ml) and CZX (50 micrograms/ml). CTM had an MIC of 100 micrograms/ml for 1 strain, and MICs of greater than 100 micrograms/ml for all of the other strains of P. aeruginosa, indicating them to be resistant to this antibiotic. All of the strains were resistant to CMZ and CEZ, showing MICs of greater than 100 micrograms/ml. 5. For each of the tested antibiotics, no correlation was found between the MIC and the serogroup for either P. aeruginosa or S. marcescens.

Bacteria↗