Biomedical subjects

M Kojima

Publications and source records attributed to M Kojima.

At least 199 records · Page 11Linked to original sources

PubMed1999

Area- and lamina-specific organization of a neuronal subpopulation defined by expression of latexin in the rat cerebral cortex.

The aim of the present study was to investigate the density, laminar distribution, size, morphology, and neurotransmitter phenotype of rat cortical neurons expressing latexin, an inhibitor of carboxypeptidase A. Immunohistochemical analyses established that latexin-immunoreactive neurons are restricted essentially to the infragranular layers of lateral cortical areas in the rat. The overall density, laminar or sublaminar localization, and cell size distribution of latexin-positive neurons differed substantially across cytoarchitectonic areas within lateral cortex. Numerous latexin-positive neurons had the morphology of modified pyramidal cells especially of layer VI. The vast majority of latexin-positive neurons were glutamate-immunoreactive in the six lateral neocortical areas examined, while neurons immunoreactive for both latexin and GABA were virtually absent. Thus the majority of latexin-positive neurons are likely to be excitatory projection neurons. The area- and lamina-specific distribution of the latexin-expressing subpopulation of glutamate-immunoreactive neurons is a distinctive feature that may contribute to the functional specialization of the lateral cortical areas.

Animals↗

PubMed1999

jumonji gene is essential for the neurulation and cardiac development of mouse embryos with a C3H/He background.

The recessive mutant mouse jumonji (jmj), obtained by a gene trap strategy, shows neural tube defects in approximately half of homozygous embryos with a BALB/cA and 129/Ola mixed background, but no neural tube defects with BALB/cA, C57BL/6J, and DBA/2J backgrounds. Here, we show that neural tube and cardiac defects are observed in all embryos with a C3H/HeJ background. In addition, abnormal groove formation and prominent flexure are observed on the neural plate with full penetrance, suggesting that abnormal groove formation leads to neural tube defects. We found morphogenetic abnormalities in the bulbus cordis (future outflow tract and the right ventricle) of homozygous embryo hearts. Moreover, myocytes in the ventricular trabeculae show hyperplasia with cells filling the ventricles. Together with the observation that the jmj gene is expressed in the neural epithelium of the head neural plate and in myocytes in the bulbus cordis and trabeculae, the results show that the jmj gene plays essential roles in the normal development of the neural plate, morphogenesis of bulbus cordis, and proliferation of trabecular myocytes on a C3H/He background.

Animals↗

PubMed1999

Trends in site-specific mortality from oral and pharyngeal cancer among Japanese males, 1950-94.

In order to obtain some etiological clues for oral and pharyngeal cancer in Japanese males, we examined mortality trends from cancer of the lip, buccal cavity and pharynx by site with other descriptive epidemiological features (1950-94). The data were obtained from Vital Statistics (Ministry of Health and Welfare, Japan). The 45-year trend in mortality was evaluated by computing crude and age-adjusted mortality rates, age-specific mortality rates, with birth cohort analysis. The crude mortality rate from cancer of the lip, buccal cavity and pharynx has increased by 3.7-fold, and age adjusted mortality rate by 1.7-fold in the 45-year period, with different mortality trends by site. In general, age-specific mortality has also been increasing with advancing age. The birth cohort analysis showed that the higher the mortality rate, the younger the birth cohort, but with different effects of birth cohort by site. Mortality from cancer of the lip, buccal cavity and pharynx has consistently been increasing in Japanese males from 1950 to 1994, with similar upward mortality trends for some specific sites.

Adult↗

PubMed1999

Hepatocyte growth factor and invasion-stimulatory activity are induced in pleural fluid by surgery in lung cancer patients.

Hepatocyte growth factor (HGF) is a stromal cell-derived cytokine that can stimulate matrix invasion by carcinoma cells. We analysed the concentrations of HGF and invasion-stimulatory activity in pleural fluid after lung surgery. The concentration of HGF in pleural fluids was measured by enzyme-linked immunosorbent assay in seven patients who underwent pulmonary resection for primary or metastatic lung cancer. The effect of the pleural fluid on cancer cell invasion across reconstituted basement membrane (Matrigel) was assessed with a Boyden chamber assay using a lung adenocarcinoma cell line, A549. HGF levels in the pleural fluid after lung surgery ranged from 6.0 to 23.0 ng ml(-1) (average: 10.2 +/- 4.3 ng ml(-1)). The matrix invasion of lung carcinoma cells in the presence of the pleural fluid was significantly higher than that in the presence of culture medium alone or sera from normal subjects (P < 0.01). The invasion-stimulatory activity of the pleural fluid was strongly inhibited by HGF-neutralizing antibody. Positive correlation was found between the HGF level and invasion-stimulatory activity in the pleural fluids and normal sera (P = 0.0073). This is the first report demonstrating that the lung surgery induces a considerable amount of HGF, which is closely correlated with the invasion-stimulatory activity of the pleural fluid.

Aged↗

PubMed1999

Pretreatment antimicrobial susceptibilities of paired gastric Helicobacter pylori isolates: antrum versus corpus.

BACKGROUND: Antimicrobial susceptibility testing of Helicobacter pylori isolates is the most useful tool for guiding specific therapy, especially when primary resistance is suspected. However, the most informative gastric biopsy site for detection of resistant H. pylori isolates is uncertain. We sought to determine whether susceptibilities to commonly used antimicrobials (amoxicillin, clarithromycin, minocycline, and metronidazole) were related to biopsy site. METHODS: H. pylori isolates were obtained from patients who had duodenal ulcer and had not received any therapy directed against H. pylori. Agar-dilution minimum inhibitory concentrations of each antimicrobial were compared between paired H. pylori isolates from the antrum and the proximal corpus. RESULTS: Differences in minimum inhibitory concentrations exceeding twofold were observed within the pairs of H. pylori isolates in 5 of the 40 patients tested. In three patients with clarithromycin-resistant isolates and two with metronidazole-resistant isolates, both antral and corporeal specimens revealed resistance. However, no patient had pairs of isolates categorized as resistant at one site and sensitive at the other. CONCLUSIONS: While we found that an individual may have a mixed H. pylori infection with respect to differing antimicrobial susceptibility in different parts of the stomach, a single biopsy specimen from either the antrum or the corpus should provide reliable detection of H. pylori isolates with primary resistance.

Adolescent↗

PubMed1999

Effect of vitamin E eye drops on naphthalene-induced cataract in rats.

The effect of vitamin E acetate (VEA) eye drops on naphthalene-induced cataract in rats was investigated by Scheimpflug image analysis. The control group was administered only naphthalene (1 g/kg), while the other group was additionally given 1% VEA eye drops into both eyes 5 times a day every day for 9 weeks from the start of naphthalene treatment. During those 9 weeks, the changes of the crystalline lens were documented by an anterior eye segment analysis system (EAS-1000, NIDEK) once a week in mydriasis (Mydrin-P, Santen Pharmaceutical Co., Ltd.). The characteristic density values of the anterior deeper cortex regions were measured. The light scattering intensity of lenses from VEA eye drop-treated animals was significantly lower than that of animals without VEA treatment. This difference was found 1 week, 4 weeks, and from 7 to 9 weeks after the start of naphthalene application. VEA eye drops may have the potential to delay the progression of naphthalene-induced cataract in rats.

Animals↗

PubMed1999

Corticocortical associative neurons expressing latexin: specific cortical connectivity formed in vivo and in vitro.

Latexin, a carboxypeptidase A inhibitor, is expressed in a subset of neurons in the infragranular layers of the lateral cortex in the rat. We here show that latexin-expressing neurons exhibit ultrastructural features common to cortical pyramidal neurons. We show in combined retrograde tracing and immunofluorescent experiments that latexin-expressing neurons contribute to specific corticocortical pathways. Thus, injections of the retrograde tracer fluorogold into either the primary somatosensory (SI) or the primary motor (MI) cortical area labeled many latexin-expressing neurons in the infragranular layers of the secondary somatosensory (SII) and visceral sensory (Vi) areas. In contrast, tracer injections involving the thalamus, striatum, or contralateral SII and Vi exclusively labeled latexin-nonexpressing neurons in both the SII and Vi. Finally, we show that the correct corticocortical projections can be formed in organotypic slice cultures in vitro from latexin-expressing neurons: when slices of developing SII were cocultured with those from the SI and the thalamus, latexin-immunoreactive neurons in the SII projected preferentially to their normal SI target. The specific connectivity formed in vivo and in vitro by this molecularly distinct neuronal population reveals its characteristic manner of cortical organization and provides a unique model system to analyze mechanisms underlying the formation of precise corticocortical pathways.

Age Factors↗

PubMed1999

Adrenomedullin and atrial natriuretic peptide concentrations in normal pregnancy and pre-eclampsia.

Adrenomedullin (AM) is a peptide that elicits a long-lasting vasorelaxant activity, while atrial natriuretic peptide (ANP) has also been shown to be a potent vasodilatory agent. To clarify the possible role of AM and ANP in the physiology of pregnancy and pathophysiology of pre-eclampsia, we measured plasma concentrations of these peptides in non-pregnant women, normal pregnant women and women with pre-eclampsia. A gradual increase in plasma AM was observed as pregnancy progressed. The plasma AM concentrations during the second trimester (12.7 +/- 1.4 fmol/ml) were significantly elevated, in comparison with the non-pregnant follicular phase (6.4 +/- 0.61 fmol/ml), luteal phase (6.0 +/- 0.49 fmol/ml), and the first trimester (6.5 +/- 0.8 fmol/ml). The plasma AM concentrations of the third trimester (21.5 +/- 1.4 fmol/ml) were significantly elevated when compared with those of the second trimester (P < 0.05). Northern blot analysis confirmed the expression of the AM mRNA transcript (1.6 kb) in third trimester placentas. In comparison with those observed at term (25.3 +/- 4.5 fmol/ml), the plasma concentrations were significantly reduced post-partum (6.4 +/- 0.6 fmol/ml). In the third trimester, plasma AM concentrations did not differ significantly between women with pre-eclampsia (17.2 +/- 2.3 fmol/ml) and normal pregnant women. In contrast, the plasma ANP concentrations in pre-eclampsia (39.5 +/- 7. 1 pg/ml) were significantly elevated when compared with those of the normal third trimester (14.4 +/- 1.4 pg/ml) (P < 0.05). ANP concentrations were reasonably constant throughout the pregnancy.

Adrenomedullin↗

PubMed1999

Hodgkin's disease expressing follicular dendritic cell marker CD21 without any other B-cell marker: a clinicopathologic study of nine cases.

Reed-Sternberg (RS) and Hodgkin's (H) cells are considered to be the neoplastic cells in Hodgkin's disease (HD). Although most data suggest their lymphoid origin, the nature of these cells still remains a subject of controversy. Recently, a number of RS cells have been found to express an antigen that is also present on follicular dendritic cells (FDCs), asserting FDCs as the possible progenitor cells of H-RS cells. This prompted us to investigate whether these CD21-positive cases had distinct clinicopathologic characteristics. In a series of 94 examined cases of HD, we identified 9 CD21-positive ones (4 of 37 cases of nodular sclerosis, 1 of 41 mixed cellularity, and 4 of 12 lymphocyte depletion HD) without any other B-cell marker on paraffin sections. The patients varied in age from 16 to 82 years (median, 50 years) and included six men and three women. They had superficial or mesenteric lymphadenopathy without hepatosplenomegaly. Peripheral blood leukocytosis was seen in three patients. The clinical course was indolent, and all patients but one achieved an initial complete response with HD-based treatment regimens, although three of them relapsed. Morphologically, two subgroups could be delineated. Six of the cases were characterized, besides by the classic RS cells, by a varying number of the cells with the distinctive walnutlike or cerebrumlike nuclei and cytologically with cytoplasmic processes. Their fine structural examination also revealed villous processes, but no desmosomes. The other three cases had multinucleated RS cells often with triangular nuclei, but not cytoplasmic processes. The percentage of CD21-positive tumor cells ranged from less than 10% to 60% among the H-RS cells. These RS cells were positive for CD30 (9 of 9), CD15 (7 of 9), CD68 (1 of 8), fascin (8 of 8), S-100 protein (1 of 7), and epithelial membrane antigen (2 of 8) on paraffin sections. Notably, of eight cases examined on frozen sections, two showed immunostaining for DRC1, CD35, R4/23, and Ki-M4p. Only CD35 was also detected in the other two cases. Genotypic investigation showed germline configuration of the T-cell receptor beta and gamma chain genes and the immunoglobulin heavy chain gene in all eight cases examined. In situ hybridization showed Epstein-Barr virus sequences in four cases, three of which were examined by the terminal region analysis and showed the Epstein-Barr virus to be monoclonal. We concluded that in a small proportion (9.6%) of HD, H-RS cells might be derived from FDCs and that they appear to represent a distinct pathologic variant based on morphologic and phenotypic traits within the framework of HD.

Adolescent↗

PubMed1999

Nodal cytotoxic lymphoma spectrum: a clinicopathologic study of 66 patients.

The expression of cytotoxic granule-associated proteins has been reported in some T-cell or natural killer (NK)-cell lymphomas of mostly extranodal origin, but rarely of nodal origin except for anaplastic large cell lymphoma (ALCL) and Hodgkin's disease (HD). This study analyzed 66 nodal lymphomas expressing T-cell intracellular antigen-1 (TIA-1) and/or granzyme B to characterize the clinicopathologic spectrum of these neoplasms. Four main groups could be delineated. The first group consisted of p80/anaplastic lymphoma kinase (ALK)-positive ALCL (n = 35). The patients were 2 to 62 years of age (median age, 16 years), and the lymphomas pursued a relatively indolent clinical course. The tumors were phenotypically of either T- or null-cell type with constant expression of CD30, epithelial membrane antigen (EMA), and p80/ALK, but not CD15 or BCL2. None harbored Epstein-Barr virus (EBV). The second group consisted of peripheral T/NK-cell lymphoma, the nodal high-grade cytotoxic type (n = 13). The patients were 29 to 72 years in age (median age, 55 years), and the tumors pursued an aggressive clinical course. The tumors often showed pleomorphic, anaplastic, or centroblastoid morphology, and were featured by either EBV association or CD56 expression. The third group consisted of peripheral T-cell lymphoma, of the nodal low-grade cytotoxic type (n = 8). The patients, three men and five women, were 31 to 75 years old (median age, 61 years). Notably, six of them exhibited lymphoepithelioid (Lennert's) lymphoma. The fourth group consisted of cytotoxic Hodgkin's-like ALCL/HD (n = 10), included seven cases of Hodgkin's-like ALCL and three cases of HD, and was characterized by the presence of Reed-Sternberg cells and often the CD15+ phenotype. The patients were all men except for one woman, and they ranged in age from 24 to 84 years (median age, 62 years). The link among these four groups was reinforced by the presence of a highly characteristic large cell with horseshoelike or reniform nuclei-the frequent expression of CD30 and EMA-and the often lack of T-cell receptor-alphabeta. In this series, the expression of p80/ALK and CD56 was also associated with favorable and poor prognoses respectively (p<0.001, log-rank test).

Adolescent↗

PubMed1999

Effect of ozagrel on locomotor and motor coordination after transient cerebral ischemia in experimental animal models.

The effect of ozagrel, a selective thromboxane A(2) (TXA(2)) synthetase inhibitor, on the obstruction after cerebral ischemia-reperfusion was studied in experimental animal models. The reduced spontaneously locomotor activity and the obstruction of motor coordination were improved by the administration of ozagrel in the conscious cerebral ischemia-reperfusion mouse model. Ozagrel suppressed the decrease in specific gravity of the brain tissue induced by the occlusion-reperfusion in the conscious cerebral ischemia-reperfusion SHR model, and recovered the postischemic decrease in cortical PO(2) after middle cerebral artery occlusion-reperfusion in cats. The level of TXB(2), a metabolite of TXA(2), in the brain increased after the cerebral ischemia-reperfusion, and ozagrel prevented this increase. Additionally, ozagrel also increased the level of 6-keto-PGF(1alpha), a metabolite of prostaglandin I(2) (PGI(2)), in the brain tissue after cerebral ischemia-reperfusion, and the administration of PGI(2) improved the reduced spontaneous locomotor activity in the conscious cerebral ischemia-reperfusion mouse model. Our data suggest that ozagrel suppressed the obstruction following cerebral ischemia-reperfusion by preserving the cerebral blood flow via preventing the increase in TXA(2) and causing an increase in the PGI(2) level.

6-Ketoprostaglandin F1 alpha↗

PubMed1999

A simple food frequency questionnaire for Japanese diet--Part I. Development of the questionnaire, and reproducibility and validity for food groups.

We developed a simple food frequency questionnaire (FFQ) based on one-day dietary records (DRs) among 1001 subjects in Nagoya, Japan. A total of 97 foods and dishes were selected through a two-step procedure; first by ranking food items according to the contribution to the population intake of nutrient variables, and second by stepwise multiple regression analyses of individual food items as the independent variables and of total nutrient intake as the dependent variables. For simplicity, questions on portion sizes were not included except for a few selected food items, which resulted in short time (about 20 minutes) to complete the questionnaire. This FFQ was validated for food groups by referring to four 4-day DRs among 88 men and women in central Japan, from 1996 to 1997. The energy-, sex- and age-adjusted test-retest correlation coefficients between the two FFQs administered at an one year interval ranged from 0.34 to 0.78. The de-attenuated, energy-, sex- and age-adjusted correlation coefficients between the second FFQ and the DRs were larger than 0.40 for most food groups, indicating the usefulness of this simple FFQ with its sufficient validity in epidemiological surveys.

Adult↗

PubMed1999

A simple food frequency questionnaire for Japanese diet--Part II. Reproducibility and validity for nutrient intakes.

A self-administered 97-item simple food frequency questionnaire (FFQ), without portion size questions for most items, was completed twice at an one-year interval by 88 men and women in central Japan to evaluate its reproducibility. This FFQ was further validated by referring to four 4-day weighed dietary records (DRs) which were performed at 3-month intervals. Mean energy and 18 nutrient intakes measured by the first and the second FFQs were quite similar to those measured by the DRs. In our reproducibility study, Pearson and intraclass correlation coefficients, adjusted for energy intake, sex and age, ranged from 0.48 to 0.82 (median = 0.67). In the validation study, adjusted and de-attenuated correlation coefficients between the second FFQ and the DRs ranged from 0.42 for iron to 0.83 for calcium (median = 0.61). The proportion of subjects classified by the FFQ into the same or adjacent quintiles defined by the DRs was between 65.9% and 83.0% (median = 69.9%). These findings essentially suggested that our FFQ is well reproducible and sufficiently valid, and therefore, reasonably useful for nutritional epidemiological studies for Japanese diets, particularly for those of Tokai Area.

Adult↗

PubMed1999

Epidemiological studies on UV-related cataract in climatically different countries.

Cataract epidemiological surveys applying objective judgement through lens images in the climatically different places of Noto and Amami, Japan, Singapore and Reykjavik, Iceland yielded several significant results about the influence of solar UV. 1) The percentage of transparent and of lens opacification was significantly higher in the Reykjavik subjects than in the Singaporeans. 2) The percentages including early changes were higher in Amami and Singapore than in Noto and Reykjavik. 3) Progressed lens opacification was highest in Singapore. While the main type of lens opacification was cortical in Noto and Reykjavik, that of Singapore was nuclear. 4) A significant correlation between cortical opacification and the history of time spent outdoors was noticed. The UV risk for formation and/or progression of cortical opacification should be acceptable from the epidemiological standpoint.

Age Distribution↗

PubMed1999

UV damage to the eye lens: further results from animal model studies: a review.

UV irradiation has the potential to induce the development of lens opacities. This has been demonstrated since long with animal experiments. Unfortunately these animal cataracts did not explain or elucidate the epidemiological observation that the frequency of human cataracts--such as the so called senile cataract--is remarkably higher in regions with increased cosmic UV irradiation or in the population being in close professional contact with UV-irradiation. The main problem was that the type of UV induced animal cataracts differs remarkably with respect to onset, localization of the opacity, size and its timely progression from the cataract classes observed in human. The research of the last 10 years comes to the conclusion that beside the direct (acute) damage--as seen in animal studies due to high UV dosages--we have to realize a syn- or co-cataractogenic potential of UV irradiation even below the threshold dose which is able to accumulate in the lens and to initiate together with other risk factors (chronic damage) the opacification of the lens. The mechanism for the animal cataract and the human cataract (with an UV risk participation) are different. The epidemiological research about cataract frequency in different regions of the world have to take into account that UV irradiation--even below a threshold dose--is a possible risk among the multifactorial pathogenesis of human cataract.

Animals↗

PubMed1999

[Bladder dysfunction in dementia patients showing urinary incontinence: evaluation with cystometry and treatment with propiverine hydrochloride].

In a total of 46 dementia patients with urinary incontinence, filling cystometry was performed to evaluate bladder function, followed by peroral administration of propiverine hydrochloride. Therapeutic effects were evaluated in terms of changes in cystometric bladder capacity and urinary incontinence. Based on cystometric findings, 58.1%, 35.3% and 6.4% of Alzheimer dementia patients proved to have overactive bladder, normoactive bladder and low compliant bladder, respectively. Similarly, 90.9% and 9.1% of vascular dementia patients had overactive detrusor and low compliance, respectively. As a result of propiverine hydrochloride administration for 2 weeks, both bladder capacity and incontinence improved in around 40%, irrespective of the dementia type (Alzheimer vs vascular). It is of interest, however, that patients with overactive bladder demonstrated more satisfactory response to the treatment than those with normoactive bladder. It is accordingly suggested that propiveline hydrochrolide is a promising treatment option for urinary incontinence in demented elderly and cystometry could be useful in predicting treatment outcome.

Aged↗

PubMed1999

Effect of timing of meal intake after squat exercise training on bone formation in the rat hindlimb.

We hypothesized that bone acquisition was affected by the timing of meal intake after resistance exercise training. This was based on the following previous results: 1) Nutrient intake right after exercise resulted in an increase in muscle mass and a decrease in abdominal fat mass as well as muscle protein synthesis when compared to the intake of a meal later after the exercise; and 2) body composition has been proposed to be a good predictor of bone mass. To substantiate our hypothesis, 20 male rats were assigned to either a group fed a meal right after squat exercise (R) or a group fed a meal 4 h after the exercise (L). The 10-wk training program consisted of approximately 70% of one repetition maximum for each animal, 15 repetitions per set, 10 sets per day, 3 d per week. As a result, hindlimb muscle mass in the R group was greater (p < 0.05) than that in the L group and abdominal fat mass was less (p < 0.01) in the R group as compared to the L group, regardless of there being no significant difference in body weight between the groups. Bone volume in the tibia (p < 0.01) and femur (p < 0.05) were both significantly greater in the R group than in the L group. Bone mineral content index (BMCI) and bone mineral density index (BMDI) in the tibia of the R group were significantly (p < 0.05) greater than the corresponding values of the L group. The greater BMCI and BMDI in the tibia were positively and significantly (p < 0.05) related with hindlimb muscle mass, but not with abdominal fat mass. There was no significant difference in BMCI and BMDI in the femur between the groups. These results suggest that the R regimen may contribute to increased bone acquisition in the tibia as compared to the L regimen, and this effect is partly due to the enlargement of muscle mass in the R group as compared to the L group.

Adipose Tissue↗

PubMed1999

Antifungal activities of D0870 against fluconazole-resistant Candida albicans.

We compared the in vitro and in vivo antifungal activities of D0870, a new triazole antifungal agent, with those of other antifungal agents against 8 clinical isolates of fluconazole-resistant Candida albicans. Microdilution testing was performed according to National Committee for Clinical Laboratory Standards (NCCLS) document M27-T. Minimal inhibitory concentration of D0870 (<0.004-1.0 micro g/ml) was lower than those of fluconazole (2->64 microEg/ml) and itraconazole (0.031-8.0 microEg/ml). In systemic infection models with C. albicans in normal and immunosuppressed mice, D0870 at 0. 3-30 mg/kg/day for 5 days after infection prolonged survival of the animals and showed the highest efficacy among the triazole antifungal agents. At pH 7 and 37C in Sabouraud dextrose broth (SDB), D0870 inhibited the growth of C. albicans and acted cytocidally against one of the middle-resistant strains. In an in vivo study against this strain, D0870 at 10 mg/kg/day for 5 days after infection significantly reduced kidney colony counts (2850+406-997+537 CFU/kidney, P<0.05) on day 7 after infection in comparison with those of the control mice at 24 h after infection. Plasma concentration of D0870 after a single oral administration at 10 mg/kg maintained a sufficient level for interpretation of in vivo antifungal activities. These results suggest that D0870 has strong antifungal activities against clinical isolates of fluconazole-resistant C. albicans in vitro and in vivo, and that these strong activities are at least partially concerned with the fungicidal action.

Animals↗