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Biomedical subjects

M Ishii

Publications and source records attributed to M Ishii.

At least 37 records · Page 2Linked to original sources
PubMed2005

A case of acquired smooth muscle hamartoma of the scrotum.

We report a case of acquired smooth muscle hamartoma (ASMH) of tunica dartos, believed to be only the fifth so far reported. A 24-year-old man had a 6-month history of an asymptomatic tight and thickened scrotum. The skin was difficult to pinch. A biopsy specimen from the skin showed increased and proliferated smooth-muscle bundles composed of well-differentiated and uniform spindle cells that showed typical features of acquired smooth muscle hamartoma. Interestingly, dilatations of the lymph vessels were noted in the upper dermis above the proliferated smooth muscles. It has been reported recently that long-standing severe lymphoedema may cause histological features mimicking ASMH. As the present case was not preceded by oedema of the scrotum, we consider this case to be true ASMH.

Adult↗
PubMed2005

Interferon-gamma is produced by CD8 T cells in response to HLA-A24-restricted hepatitis C virus epitopes after sustained virus loss.

Differences in cytotoxic T lymphocyte activity in hepatitis C virus infection may account for the outcome of interferon monotherapy. To investigate this hypothesis, we analysed the response of peripheral CD8(+) T cells that recognized epitopes presented by HLA-A*2402. We synthesized HLA/beta2-microglobulin/peptide complexes using two epitopes. Production of interferon-gamma by CD8(+) T cells in response to plastic-bound monomeric HLA/peptide complex was observed frequently in sustained virus responders (SVR) (n = 13) against all the peptides, NS31296-1304 (the percentage of responding patients, 61.5%) and core 129-137 (53.8%), while no interferon-gamma production was observed in non-responders (NR) (n = 13) for any of the peptides. Tetramer-staining showed the presence of CD8(+) T cells specific for all the peptides except NS31296-1304 in two SVR at the end of interferon monotherapy, although hardly any such cells were found in four NR. Specific killing was observed against peptides NS31296-1304 (3/4) and core 129-137 (1/4) in sustained responders but none in non-responders. These results suggest that the responses of cytotoxic T lymphocytes (CTLs) were induced during interferon therapy in these patients and that interferon-gamma production by CD8(+) T lymphocytes against HCV NS31296-1304 and core 129-137 are well maintained in patients with SVR compared with those with NR. These findings emphasize the importance of the CD8(+) T cell response in controlling HCV infection.

Adult↗
PubMed2005

Testicular dynamics in Syrian hamsters exposed to both short photoperiod and low ambient temperature.

The object of this study was to determine the details of morphological dynamics of spermatogenesis in Syrian hamsters exposed to both short photoperiod and low ambient temperature. Eight-week-old male hamsters, kept in a long photoperiod (14 h L, 10 h D), were transferred to a short photoperiod (6 h L, 18 h D) and kept there for 13 weeks to induce testicular regression. Some hamsters were then transferred from the room at 23 degrees C to that at 5 degrees C (5 degrees C group). Remaining hamsters were continuously kept at 23 degrees C (23 degrees C group). Thereafter, the morphology was examined. As a result, it took only 8 weeks until spermatogenesis recovered in the 23 degrees C group. However, it was not until 20 weeks that spermatogenesis was recognized in the 5 degrees C group. As the regulation of seasonal testicular activity is characterized by coordinated shifts in the relationships among mitosis, meiosis, and apoptosis, the changes in the proliferative and apoptotic activities were examined. Although no significant difference in proliferative activity of spermatogonia between the 5 degrees C and the 23 degrees C groups was confirmed, a notable increase in the rate of apoptosis was observed in the 5 degrees C group. Furthermore, this increase was more salient during the hibernation period. These findings suggest that both cold ambient temperature and hibernation caused the delay of testicular recrudescence and this delay arose from the increase of apoptotic activity but not the change in proliferative activity in spermatogonia in the 5 degrees C group.

Animals↗
PubMed2004

Induction of canine pyometra by inoculation of Escherichia coli into the uterus and its relationship to reproductive features.

To characterize oestrus-related factors affecting the induction of and recovery from pyometra in bitches, 60 clinically healthy beagle bitches were used for induction of pyometra by inoculation of Escherichia coli into the uterus during oestrous and metoestrous stages. The animals were classified into the following six groups according to inoculation time: Days 1-10, 11-20, 21-30, 31-40, 41-50 and 51-60 after LH surge. The incidence of pyometra during the periods Days 11-20 and 21-30 after LH surge was 90.9% and 78.9% respectively, while that during Days 1-10 and 51-60 after LH surge was less than 20%, and the patterns of the incidence of pyometra and the serum progesterone levels were similar. There was no difference in the incidence of pyometra induced in bitches less than 5 years old compared to bitches over 6 years old. Oestrus in all of the bitches with pyometra induced by E. coli returned with or without PGF 2alpha treatment, unlike in bitches with spontaneous pyometra. The duration of the oestrous cycle in the non-treated and PGF 2alpha-treated groups was 231.4+/-55.2 days and 162.1+/-40.6 days (P < 0.001), respectively, and there was no difference in the rate of return of oestrus between the two groups. The conception rate in all of the bitches in which oestrus had returned was 81.8%. The above findings indicate that the period during which severe pyometra could be induced was limited to the early stage in metoestrus.

Animals↗
PubMed2004

Occurrence, biochemistry and possible biotechnological application of the 3-hydroxypropionate cycle.

The 3-hydroxypropionate cycle, a pathway for autotrophic carbon dioxide fixation, is reviewed with special emphasis on the biochemistry of CO2 fixing enzymes in Acidianus brierleyi, a thermophilic and acidophilic archeon. In the 3-hydroxypropionate cycle, two enzymes, acetyl-CoA carboxylase and propionyl-CoA carboxylase, catalyze CO2 fixation. It has been shown in A. brierleyi, and subsequently in Metallosphaera sedula, that acetyl-CoA carboxylase is promiscuous, acting equally well on acetyl-CoA and propionyl-CoA. The subunit structure of the acyl-CoA carboxylase was shown to be alpha4beta4gamma4. Gene cloning revealed that the genes encoding the three subunits are adjacent to each other. accC encodes the beta-subunit (59 kDa subunit, biotin carboxylase subunit), accB encodes the gamma-subunit (20 kDa subunit, biotin carboxyl carrier protein), and pccB encodes the alpha-subunit (62 kDa subunit, carboxyltransferase subunit). Sequence analyses showed that accC and accB are co-transcribed and that pccB is transcribed separately. Potential biotechnological applications for the 3-hydroxypropionate cycle are also presented.

Acetyl-CoA Carboxylase↗
PubMed2004

Single-acquisition sequence for the measurement of oxygen partial pressure by hyperpolarized gas MRI.

Magnetic resonance imaging (MRI) with hyperpolarized 3-helium gas (HP 3He) offers the possibility of studying functional lung parameters such as the alveolar oxygen concentration and oxygen depletion rate. Until now, a double-acquisition technique has been utilized to extract these parameters. A complicated single-acquisition technique was previously developed to avoid the necessity of performing two identical breathing maneuvers. The results obtained with this technique were significantly less accurate than the results obtained with the double-acquisition method. In this work, a novel, easily implemented single-acquisition sequence is presented that provides results comparable to those obtained with the established double-acquisition method. This method is demonstrated in a phantom and a pig model on a 1.5 T scanner using a 2D fast low-angle shot (FLASH) gradient-echo sequence. Numerical simulations of the time evolution of the oxygen concentration were performed. Simulation results are presented to support the experimental data. Various parameter regimes were experimentally and numerically investigated.

Animals↗
PubMed2004

A small animal model of regional alveolar ventilation using HP 3He MRI1.

RATIONALE AND OBJECTIVES: The aim of this study was to establish a standardized procedure for the measurement of regional fractional ventilation in a healthy rat model as a baseline for further studies of pulmonary disorder models. MATERIALS AND METHODS: The lungs of five healthy male Sprague-Dawley rats were imaged using hyperpolarized helium-3 magnetic resonance imaging. From these images, regional fractional ventilation was calculated and maps generated detailing the distribution of fractional ventilation in the lung. The 1.56 mm x 1.56 mm x 4 mm regions of interest were assigned on 5 cm x 5 cm field of view lung maps. Histograms were also generated showing the frequency distribution of fractional ventilation values. To compare fractional ventilation values between animals, the ventilation procedure was standardized to results from individual pulmonary function tests. Each animal's spontaneous tidal volume, respiratory rate, and inspiration percentage (percent of total respiratory cycle in inspiration) were used in their mechanical ventilation settings. RESULTS: Results were similar among all five healthy rats based on examination of ventilation distribution maps and frequency distribution histograms. Mean (0.13) and standard deviation (0.07) were calculated for fractional ventilation in each animal. However, these values were determined to be influenced by slice selection, and therefore the maps and histograms were favored in analysis of results. CONCLUSION: This study shows consistent results in healthy rat lungs and will serve as a baseline study for future measurements in emphysematous rat lungs.

Animals↗
PubMed2004

Encephalomalacic lesions in pigs dually infected with porcine reproductive and respiratory syndrome virus and pseudorabies virus.

Four pigs (group 1) were infected with an aerosol containing porcine reproductive and respiratory syndrome virus (PRRSV) followed 7 days later by pseudorabies virus (PRV). Three further pigs (group 2) received PRRSV alone, two (group 3) received PRV alone, and two (group 4) remained as uninfected controls. Despite the admittedly small numbers of animals, the experiment appeared to throw light on aspects of synergy. Thus, the group 1 pigs showed severe neurological signs characterized by ataxia and muscular tremors. Total cell numbers in the bronchoalveolar lavage fluid were increased in all PRRSV-infected pigs, and PRRSV antigen was detected in the alveolar macrophages. Total cell numbers in the cerebrospinal fluid of group 1 pigs were considerably greater than those demonstrated in group 3, but no PRV antigen was found. Pigs of groups 1 and 2 showed pulmonary lesions, characterized by interstitial pneumonia and PRRSV antigen immunolabelling. Non-suppurative encephalitis was found in five of the six pigs of groups 1 and 3. In particular, one group 1 animal had severe necrotizing encephalitis with intranuclear inclusion bodies and associated immunolabelling of PRV antigen. The other three group 1 pigs had prominent malacic lesions, with macrophages. These neuropathological findings strongly suggested that PRRSV infection in pigs enhances the severity of brain lesions caused PRV.

Animals↗
PubMed2004

Mild phenotype of familial cylindromatosis associated with an R758X nonsense mutation in the CYLD tumour suppressor gene.

Familial cylindromatosis is a rare dominantly inherited disease characterized by the development of multiple benign tumours of the skin appendages, including cylindromas, trichoepitheliomas and spiradenomas. The gene responsible was positionally cloned recently, and was designated CYLD. We describe a family with cylindromatosis, in which affected individuals have an inherited R758X nonsense mutation of CYLD. Affected members of this family manifest a relatively mild tumour phenotype; the largest tumour was only 30 mm in diameter. Thus far, there is no evident genotype-phenotype relationship in cylindromatosis, although the number of families reported with both phenotypic and genotypic data remains small.

Adult↗
PubMed2004

Effect of saliva on an antimicrobial tissue conditioner containing silver-zeolite.

The purpose of this study was to evaluate the influence of human saliva on the antimicrobial effect of a tissue conditioner containing an antibiotic agent, silver-zeolite. Samples of each tissue conditioner with or without silver-zeolite were prepared and a plastic disk was used as a control. Candida albicans and nosocomial respiratory infection-causing bacteria, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Pseudomonas aeruginosa and the Streptococcus milleri group (S. constellatus and S. intermedius), were selected as test microorganisms. Antimicrobial effects of samples after water or saliva immersion for 28 days were evaluated by counting the number of viable cells [colony forming unit (CFU)] in each microbial suspension (100 microL). All data were statistically analysed by one-way anova and Bonferroni's test (P < 0.05). The antimicrobial effects of samples with silver-zeolite immersed in saliva against C. albicans, S. aureus and MRSA were observed while CFU of P. aeruginosa indicated no significant difference from that of the control. As for the S. milleri group, its CFU after saliva immersion showed the significantly smaller value than that of the control. It is concluded that the antimicrobial effects of samples containing silver-zeolite against all tested microbes except for P. aeruginosa and the S. milleri group are not influenced by saliva immersion for 28 days.

Anti-Bacterial Agents↗
PubMed2004

Thermal characteristics of recombinant green fluorescent protein (GFPuv) extracted from Escherichia coli.

AIMS: The thermal stability of isolated and extracted recombinant green fluorescent protein (GFPuv) was evaluated by analysing the loss of fluorescence intensity. METHODS AND RESULTS: GFPuv was expressed by Escherichia coli, extracted by the three-phase partitioning method and purified by elution through an hydrophobic interaction column. The collected fractions were further diluted in Tris-HCl-EDTA (pH 8.0) and subjected to continuous heating at set temperatures (45-95 degrees C). From a standard curve relating fluorescence intensity to GFPuv concentration, the loss of fluorescence intensity was converted to denatured GFPuv concentration (microg ml-1). To determine the extent of the thermal stability of GFPuv, decimal reduction times (D-values), z-value and energy of activation (Ea) were calculated. CONCLUSIONS: For temperatures between 45 and 70 degrees C, extracted native GFPuv activity decreased from 11 to 75% relative to initial native protein concentration above 70 degrees C, the average decrease in GFPuv fluorescence was between 72 to 83%. SIGNIFICANCE AND IMPACT OF THE STUDY: The thermal stability of GFPuv provides the basis for its potential utility as a fluorescent biological indicator to assess the efficacy of the treatment of liquids and materials exposed to steam.

Cloning, Molecular↗