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Biomedical subjects

M Kurosawa

Publications and source records attributed to M Kurosawa.

At least 37 records · Page 2Linked to original sources
PubMed2000

Stem cell factor and IL-6 do not promote complete maturation of human cultured mast cells from umbilical cord blood cells: an ultrastructural study.

Human mast cells are classified into two phenotypes based on their neutral protease compositions. One type is a tryptase-positive and chymase-positive MCTC cell that is predominant in the skin, another is a tryptase-positive and chymase-negative MCT cell that is predominant in the lung. Cord blood-derived human mast cells cultured in the presence of stem cell factor and interleukin-6 are a mixture of MCTC and MCT at various ratios, as revealed by immunocytochemical staining. We performed an electron microscopic analysis of cord blood-derived human cultured mast cells and found that they were so immature that we could not distinguish MCT and MCTC from their ultrastructural morphology. The response to secretagogues was not the response of MCTC but rather of MCT. Although human cultured mast cells are the most useful cells for use in in vitro experiments, the present culture condition supplemented with stem cell factor and interleukin-6 does not develop fully mature mast cells in vitro.

Cell Differentiation↗
PubMed2000

Mast cells in the cutaneous lesions of sarcoidosis: their subtypes and the relationship to systemic manifestations.

Possible involvement of mast cells in pulmonary sarcoidosis has been suggested, however whether mast cells are involved in cutaneous sarcoidosis remains unknown. We undertook a morphological study of mast cells in the lesional skin from 17 patients with cutaneous sarcoidosis using immunohistochemical methods. Mast cells were present in non-parenchymal fibrous areas, but not in granulomatous areas, in the biopsy specimens from the cutaneous lesions. However, there were no significant differences between the number of mast cells in the lesional skin and that in non-lesional skin from the patients. Mast cells containing substantial quantities of both tryptase and chymase (MC(TC) cells) were present in 41% of the patients, and cells containing tryptase but not chymase (MC(T) cells) were present in 59% of patients. All patients of the former group showed systemic manifestations of the disease concomitantly. Serum angiotensin I-converting enzyme levels were elevated in 71.4% of the former group, and in 30% of the latter group. This study for the first time demonstrated that mast cells were present in non-parenchymal fibrous areas of the cutaneous lesions of sarcoidosis, and the mast cell subtypes may be related to systemic manifestations.

Adult↗
PubMed2000

Cultured human mast cells derived from umbilical cord blood cells in the presence of stem cell factor and interleukin-6 cannot be a model of human skin mast cells: fluorescence microscopic analysis of intracellular calcium ion mobilization.

To know whether cultured human mast cells raised from umbilical cord blood cells in the presence of stem cell factor (SCF) and interleukin-6 (IL-6) can be a model of human skin mast cells, the cells were stimulated, and intracellular calcium ion ([Ca(2+)](i)) mobilization was analyzed by fluorescence microscopic techniques in parallel with a measurement of histamine released from the cells. When IgE-sensitized mast cells were activated by anti-IgE, [Ca(2+)](i) elevation began at the periphery and subsequently proceeded toward the center of the cells. The increase in [Ca(2+)](i) in calcium ionophore A23187-stimulated mast cells began at the center and spread to the periphery of the cells. Significant histamine release was observed by each stimulation. However, either compound 48/80 or substance P failed to increase [Ca(2+)](i) with no appreciable histamine release. This study shows that there is heterogeneity of [Ca(2+)](i) mobilization in the activated human mast cells, and that cultured human mast cells derived from umbilical cord blood cells in the presence of SCF and IL-6 can not be a model of human skin mast cells.

Antibodies, Anti-Idiotypic↗
PubMed2000

Exogenous cholecystokinin-8 reduces vagal efferent nerve activity in rats through CCK(A) receptors.

It has been proposed that the vagus nerve plays a role in mediating cholecystokinin-8 (CCK-8) effect on such gastric functions as motility, emptying and gastric acid secretion. To examine the contribution of the efferent pathways in realizing these effects, efferent mass activity in the ventral gastric vagal nerve in Sprague-Dawley rats was recorded. Intravenous infusion of CCK-8 (0.1-1 nmol) suppressed the efferent activity. The effect of CCK-8 was significantly reduced in animals with total subdiaphragmatic vagotomy in comparison to those with partial vagotomy. Intravenous infusion of CCK(A) receptor antagonist L-364,718 (1-100x10(-6) g) blocked the response of vagal efferent activity to 0.1 nmol CCK-8, but the CCK(B) receptor antagonist L-365,260 (1-100x10(-6) g) did not in the conditions of either partial or total vagotomy. Intracisternal infusion of L-364,718 (1x10(-6) g) blocked the response of vagal efferent activity to 0.1 nmol CCK-8 i.v. Infusion of exogenous CCK-8 did not affect the activity of supradiaphragmatic vagal afferents. The results suggest that the effect of systemically administered CCK-8 on vagal efferent activity is mediated by both peripherally (subdiaphragmatically) and centrally localized CCK(A) receptors.

Animals↗
PubMed2000

Nerve growth factor prevents apoptosis of cord blood-derived human cultured mast cells synergistically with stem cell factor.

BACKGROUND: Stem cell factor (SCF) has been identified as a critical survival factor of human mast cells. Other cytokines which possess survival promotion activity on human mast cells are less known. OBJECTIVE: We examined the survival promotion activity of nerve growth factor (NGF) on cord blood-derived human cultured mast cells. METHODS: Expression and function of NGF receptors on the mast cells were examined by RT PCR, flowcytometric analysis, immunoprecipitaion and western blotting. The survival promotion activity of NGF to the mast cells was examined. To evaluate the proliferating activity of NGF on the human cultured mast cells, flow cytometric analysis with propidium iodide staining was applied. To confirm whether the human mast cell growth activity of NGF was caused by a suppression of apoptosis, the proportion of the cells containing in situ DNA fragmentation was counted. RESULTS: The human cultured mast cells expressed the high affinity receptor p140trk but not the low affinity receptor p75LNGFR. NGF induced the phosphorylation of p140trk. NGF alone could not support the survival of the mast cells, however, the addition of NGF to the culture medium containing recombinant SCF led to a significant increase of the number of survival mast cells. No significant changes of the cell cycle from G0/G1 phase to the S/G2 + M phases were observed by NGF. In contrast, the addition of NGF to the medium with SCF showed a significant inhibitory effect on the apoptosis of the mast cells. CONCLUSION: NGF may act as a key factor to promote the survival of human mast cells synergistically with SCF through the prevention of apoptosis.

Apoptosis↗
PubMed2000

Relationship between Helicobacter pylori infection and smoking and drinking habits.

BACKGROUND: Helicobacter pylori is a major cause of various gastroduodenal diseases. Some risk factors related to H. pylori infection have been reported; however, studies on the relationship between H. pylori infection and smoking or drinking habits have given conflicting results. In the present study, these relationships were investigated by collecting sera and information from 8837 subjects. METHODS: Serum H. pylori immunoglobulin G antibody was measured by an enzyme-linked immunoassay. In addition to sex and age, information on smoking and drinking habits was collected by questionnaire. Age- and sex-adjusted odds ratios (95% confidence interval) of smoking and alcohol consumption were calculated for H. pylori seropositivity using logistic regression models. RESULTS: Current smokers had a 0.82 (0.74-0.91)-fold greater risk of H. pylori seropositivity than those who had never smoked. Current cigarette consumption showed a dose-dependently negative association with H. pylori seropositivity, and the association between smoking and H. pylori infection was strong in younger subjects. Current drinkers had a 0.88 (0.79-0.98)-fold greater risk of H. pylori seropositivity than those who had never drunk alcohol. The volume of alcohol consumed showed a negative association with H. pylori seropositivity. CONCLUSIONS: In the current study, smoking was negatively associated with H. pylori infection. The risk of H. pylori seropositivity decreased linearly with cigarette consumption per day. Increased gastric acidity in the stomach through smoking may be a cause of the dose-dependently negative association between H. pylori and smoking. Drinking was negatively and dose-dependently associated with H. pylori positivity, although the effect of drinking was weaker than that of smoking.

Adult↗
PubMed2000

Helicobacter pylori infection among Japanese children.

BACKGROUND: In Japan, there are few reports describing Helicobacter pylori infection among young children. The aim of the present study was to identify risk factors associated with H. pylori in school-aged children. METHODS: Subjects were first-grade students of three elementary schools (n = 310) and second-grade students of a junior high school (n = 300). Personal information, such as student's medical history, parent's history, family size, sibshipsize and household pets, was collected from guardians using a questionnaire. Saliva samples and personal information were collected twice (1995 and 1996). By using the saliva samples, H. pylori IgG antibody was measured using a commercial kit. To analyze the risk factors for H. pylori infection, sex- and age-adjusted odds ratios (OR) were calculated using a multiple logistic model. RESULTS: Among the children, factors related to Helicobacter antibody in saliva included spending a longer period of time in a nursery school or kindergarten (OR = 4.0) and a maternal history of stomach disease (OR = 2.8). Birth order (OR = 2.2), sleeping situation (OR = 2.3) and sibshipsize (OR = 1.6) were not factors that were significantly related to Helicobacter antibody in the saliva. Chewing food for the infant, family size, rooms in the household, sharing a bedroom during childhood, pets, a past history and a paternal history were not related to positivity. CONCLUSIONS: The results indicate that transmission is person-to-person, mainly through close contact with other children and intrafamilial infection. Helicobacter pylori infection seems to occur frequently early in life, probably before 6 years of age.

Adolescent↗
PubMed2000

Effect of mast cell-derived mediators and mast cell-related neutral proteases on human dermal fibroblast proliferation and type I collagen production.

BACKGROUND: Possible involvement of mast cells in various fibrotic conditions has been suggested, but the relative contribution of each mast cell mediator and neutral protease to fibroproliferative activity remains to be elucidated. OBJECTIVE: We investigated the effect of mast cell-derived mediators and mast cell-related neutral proteases on type I collagen production and proliferation by human dermal fibroblasts. METHODS: Mast cell-derived mediators or neutral proteases were added to cultured fibroblasts from normal dermis, and cell proliferation and type I collagen synthesis were assayed. RESULTS: Fibroblast proliferation was increased by 2.8 x 10(-9) mol/L prostaglandin D(2) and 10 microgram/mL carboxypeptidase A, but not by leukotriene D(4) or cathepsin G at the concentrations studied. Proliferation was increased by tryptase in a concentration-dependent manner, and a significant increase was observed at concentrations of 1 and 10 microgram/mL. Production of type I collagen by fibroblasts was increased in the presence of 2.0 x 10(-9) mol/L leukotriene D(4) and 10 microgram/mL tryptase. CONCLUSION: Mast cell-derived mediators prostaglandin D(2) and leukotriene D(4) and mast cell-related neutral proteases carboxypeptidase A and tryptase increase the proliferation and type I collagen production of human dermal fibroblasts in various manners.

Cell Division↗
PubMed2000

Influence of IgE-mediated activation of cultured human mast cells on proliferation and type I collagen production by human dermal fibroblasts.

BACKGROUND: Mast cells have been suggested to be involved in fibrotic conditions, but it still remains unknown whether IgE-mediated activation of human mast cells promotes fibrogenesis by human fibroblasts. OBJECTIVE: The purpose of this study was to determine whether IgE-mediated activation of cultured human mast cells can promote fibrogenesis by cultured human dermal fibroblasts. METHODS: Mast cells derived from human umbilical cord blood cells were incubated with IgE and then activated by anti-IgE, and histamine release was measured. IgE-sensitized mast cells were cocultured with fibroblasts from normal dermis and activated with anti-IgE to induce histamine release, after which proliferation and type I collagen synthesis by the fibroblasts were determined. RESULTS: Coculture of subconfluent human dermal fibroblasts with IgE-sensitized mast cells did not affect fibroblast proliferation. However, fibroblast proliferation was increased by activated mast cells, and a significant increase was observed in the presence of 10(5) or 3 x 10(5) mast cells/mL. The promotion of fibroblast proliferation by mast cells (3 x 10(5)/mL) was partly inhibited by ketotifen at a concentration that significantly reduced histamine release from mast cells. On the other hand, IgE-mediated activation of mast cells did not increase type I collagen production by confluent human dermal fibroblasts. CONCLUSION: IgE-mediated activation of cultured human mast cells could increase the proliferation of human dermal fibroblasts, but did not promote type I collagen production by the fibroblasts under the conditions tested.

Cell Division↗
PubMed2000

Production of fibrogenic cytokines by cord blood-derived cultured human mast cells.

BACKGROUND: Mast cells are a potential source of cytokines, but their contribution to nonallergic inflammatory conditions, such as fibrosis, remains unclear. OBJECTIVE: We investigated whether cord blood-derived cultured human mast cells could produce fibrogenic cytokines by IgE-mediated activation. METHODS: Mast cells were obtained from human cord blood mononuclear cells by culture with stem cell factor and IL-6. The mast cells were incubated with human myeloma IgE and were activated with anti-IgE. The expression of messenger RNA for fibrogenic cytokines was examined by the reverse-transcription polymerase chain reaction, and cytokine protein was assayed by enzyme-linked immunosorbent assay, or bioassay. RESULTS: Cultured human mast cells constitutively expressed mRNA for transforming growth factor-beta(1), and its expression was not increased by anti-IgE stimulation. The cells released this factor into the culture medium spontaneously, which showed bioactivity after heat treatment. The mast cells also expressed mRNA for platelet-derived growth factor A, which was enhanced with a peak at 3 hours by stimulation with anti-IgE. Conditioned medium from nonactivated mast cells did not contain basic fibroblast growth factor, but this cytokine was released into the medium in a time-dependent manner after stimulation with anti-IgE. CONCLUSION: Human mast cells activated by IgE-mediated stimulation show production of fibrogenic cytokines that varies depending on the cytokine, which suggests possible involvement of mast cell cytokines in the development of fibrosis.

Cells, Cultured↗
PubMed2000

Long-term effect of Helicobacter pylori infection on serum pepsinogens.

Serum pepsinogen values are markers of gastric mucosal status and of gastric cancer risk. The effect of Helicobacter pylori infection and sibship size on change of serum pepsinogen values over a seven-year span was investigated. Data from 2584 subjects with phlebotomy were analyzed both in 1989 and in 1996. The subjects were classified by H. pylori serology and sibship size (1 - 3 vs. 4 and more). Pepsinogen I (PG I) to II (PG II) ratio in '96 minus that in '89 was defined as DeltaPG I / II and compared among the groups. DeltaPG I / II was lower and decrease of PG I / II was more frequent among H. pylori-positive subjects than among negative subjects. The difference was owing to a decrease of PG I in all subjects and owing to an increase of PG II in those not younger than 30 years in '89. In H. pylori-positive subjects, those with a larger sibship size showed lower DeltaPG I / II and higher frequency of PG I / II decline. H. pylori infection exerts a reducing effect on PG I / II during the seven-year span. The effect of H. pylori is stronger among those with a larger sibship size, who are expected to have been infected with H. pylori in childhood. Inducing atrophy of gastric mucosa, which is reflected by a decline of PG I / II, may be one of the mechanisms through which H. pylori elevates the risk of gastric cancer.

Adult↗
PubMed2000

Effect of age on the relationship between gastric cancer and Helicobacter pylori. Tokyo Research Group of Prevention for Gastric Cancer.

Helicobacter pylori is thought to be involved in the pathogenesis of gastric cancer, but the time point at which it produces its effects (critical time) is unknown. We measured the serum level of H. pylori antibody in 787 gastric cancer patients and 1007 controls aged 20 to 69. Odds ratios for different gastric cancer types and stages were determined for each 10-year age class. The overall odds ratio for gastric cancer decreased with age, being 7.0 for those aged 20 - 29, 14.5 for those aged 30 - 39, 9.1 for those aged 40 - 49, 3.5 for those aged 50 - 59, and 1.5 for those aged 60 - 69 (trend in odds ratios: P < 0.01). However, there was no such age-dependent trend for early diffuse-type cancer; the odds ratios were 12.6, 4.0, 7.2, 6.5, and 18.5 respectively (P = 0.29). Early cancer tended to show higher seroprevalence than advanced cancer, especially in older subjects. No significant difference in seroprevalence was observed between diffuse and intestinal cancers within each age-class. Seroreversion must have occurred in the time interval between the critical time and the diagnosis of the cancer, especially in older patients. The age-dependent relationship between H. pylori and gastric cancer may be due to seroreversion, which itself may be independent of age. This age-independence indicates that prolonged exposure to H. pylori does not increase the magnitude of its influence on gastric carcinogenesis. Possible mechanisms through which H. pylori exerts pathogenic effects are continuous inflammation in adulthood and / or irreversible damage to gastric mucosa in childhood or the teenage years.

Adult↗
PubMed2000

ERK signaling mediates the induction of inflammatory cytokines by bufalin in human monocytic cells.

Treatment of human leukemia THP-1 cells with bufalin, a specific inhibitor of Na(+)-K(+)-ATPase, sequentially induces c-fos and inflammatory cytokines interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) gene expressions before the appearance of mature phenotypes of monocytic cells. In this study we examined the signal transduction leading to bufalin-induced gene expressions. Bufalin selectively activated extracellular signal-regulated kinase (ERK), compared with other mitogen-activated protein (MAP) kinase family members. Pretreatment of THP-1 cells with PD-98059, an inhibitor of the ERK-kinase cascade, abolished bufalin-induced c-fos and IL-1 beta gene expressions, indicating that the ERK-kinase cascade mediates the induction of inflammatory cytokines by bufalin. Inhibition of the Na(+)/Ca(2+) exchanger by KB-R7943 and of protein kinase C (PKC) by Ro-31-8220 suppressed ERK activation and gene expressions of c-fos and IL-1 beta. These findings suggest that Na(+)-K(+)-ATPase inhibition by bufalin induces calcium influx and thereby activates PKC and ERK. In cells treated with an inhibitor of p38 MAP kinases, SB-203580, bufalin-mediated ERK activation became persistent and the induction of IL-1 beta and TNF-alpha expressions was significantly augmented. These results suggest that cross talk in bufalin-mediated ERK activation is negatively regulated by endogenous p38 MAP kinase activations.

Bufanolides↗
PubMed2000

Development of a novel enzyme-linked immunosorbent assay for blood and urinary eosinophil-derived neurotoxin: a preliminary study in patients with bronchial asthma.

BACKGROUND: Eosinophil-derived neurotoxin (EDN), also called eosinophil protein X (EPX), has been suggested to be a useful marker of eosinophilic inflammation. However, no commercial enzyme-linked immunosorbent assay (ELISA) kit for EDN is available yet. METHODS: EDN was purified from pooled urine from healthy male volunteers. Polyclonal and monoclonal anti-EDN antibodies were subsequently raised, and a sandwich ELISA for EDN was established. EDN levels in serum, plasma and urine from asymptomatic patients with bronchial asthma were measured by the ELISA method. Some of the blood samples were also measured by a commercial radioimmunoassay (RIA) kit. RESULTS: The ELISA method detected human EDN with a minimum detection limit of less than 0.62 ng/ml and did not cross-react with other eosinophil granule cationic proteins including eosinophil cationic protein. The intra- and interassay coefficients of variation of the ELISA method ranged from 2.6 to 3.6% and from 6.5 to 9.4%, respectively. Good linearity was observed with serially diluted different samples, and the recoveries of the purified EDN added to serum samples ranged from 85 to 110%. Median EDN concentrations in serum (36.9 vs. 19.1 ng/ml), plasma (23.0 vs. 14.5 ng/ml) and urine (118.2 vs. 72.1 microg/mmol Cr) were significantly raised in asymptomatic asthmatic patients compared with healthy control subjects. EDN levels in serum, plasma and urine from the patients significantly correlated with the number of peripheral blood eosinophils, but not total serum IgE levels. A significant relationship between EDN values measured by the EPX-RIA kit and the EDN-ELISA method was observed. CONCLUSIONS: We have developed a novel efficient ELISA method to specifically measure blood and urinary EDN, which may be useful to study the role of eosinophils in allergic diseases including bronchial asthma.

Asthma↗