Biomedical subjects

H Agata

Publications and source records attributed to H Agata.

At least 19 recordsLinked to original sources

PubMed2007

Effective bone engineering with periosteum-derived cells.

Bone augmentation via tissue engineering has generated significant interest. We hypothesized that periosteum-derived cells could be used in place of bone marrow stromal cells (which are widely used) in bone engineering, but the differences in osteogenic potential between these 2 cell types are unclear. Here, we compared the osteogenic potential of these cells, and investigated the optimal osteoinductive conditions for periosteum-derived cells. Both cell types were induced, via bFGF and BMP-2, to differentiate into osteoblasts. Periosteal cells proliferated faster than marrow stromal cells, and osteogenic markers indicated that bone marrow stromal cells were more osteogenic than periosteal cells. However, pre-treatment with bFGF made periosteal cells more sensitive to BMP-2 and more osteogenic. Transplants of periosteal cells treated with BMP-2 after pre-treatment with bFGF formed more new bone than did marrow stromal cells. Analysis of these data suggests that combined treatment with bFGF and BMP-2 can make periosteum a highly useful source of bone regeneration.

Adolescent↗

PubMed2001

[Phase I study with irinotecan hydrochloride (CPT-11) for advanced neuroblastoma].

A Phase I trial of irinotecan hydrochloride (CPT-11) was performed to determine the maximum tolerated dose (MTD), the dose-limiting toxicities, and the incidence and severity of other toxicities in children with advanced neuroblastoma. Three children received 11 courses of CPT-11 administered as a 90-min i.v. infusion, daily for 3 days every 21 days. Doses ranged from 100 mg/m2 to 220 mg/m2. Two peaks in the total number of instances of diarrhea was observed, 25 stools at 3 days and 32 stools at 10 days. Myelosuppression was well controlled and of brief duration. One child achieved a clinical complete response (CR) and 2 had a partial response (PR). The MTD of CPT-11 administration was 180 mg/m2 for 3 days. These results indicate the usefulness of CPT-11 for the treatment of advanced neuroblastoma. Further investigation is necessary to establish its role in combination chemotherapeutic regimens.

Adrenal Gland Neoplasms↗

PubMed2000

Dependence of Temperature-Sensitivity of Poly(N-isopropylacrylamide-co-acrylic acid) Hydrogel Microspheres upon Their Sizes.

Monodisperse poly(N-isopropylacrylamide-co-acrylic acid) hydrogel microspheres were prepared by a membrane emulsification method using membranes of pore diameters of 0.33, 0.73, 1.15, and 1.70 µm. The hydrogels were synthesized by polymerization of 3.6 M N-isopropylacrylamide (N-IPAAm or NIPAM) and 0.4 M acrylic acid (AAc). Their surface properties were studied by measuring the electrophoretic mobility of the microspheres in electrolyte solutions at pH 7.4 at 25, 30, 33, 35, 40, and 45 degrees C. Poly(N-IPAAm-co-AAc) microspheres have shown negative mobility. More negative values of electrophoretic mobility were obtained with the smaller microspheres than the larger ones at each temperature. The surface charge density of the microspheres increased and their surfaces became harder above 35 degrees C, since the microspheres contained thermosensitive poly(N-IPAAm) moiety and LCST increased by the addition of AAc, while that of poly(N-IPAAm) was 33 degrees C. It has recently been found that the smaller microspheres exhibit the stronger dependence of both surface charge density and softness on the temperature. Copyright 2000 Academic Press.

Journal Article↗

PubMed1999

Felypressin-induced reduction in coronary blood flow and myocardial tissue oxygen tension during anesthesia in dogs.

PURPOSE: To determine whether felypressin reduced myocardial tissue oxygen tension (PmO2). METHODS: Seven open-chest dogs were studied under nitrous oxide and isoflurane anesthesia. Hemodynamic variables including heart rate (HR), blood pressure (BP), mean pulmonary arterial pressure (MPAP), PmO2 and coronary blood flow (CBF) were continuously recorded. After baseline measurements, felypressin was infused at 0.15, 0.3, 0.6 and 1.0 IU x hr(-1) in a successive manner. Hemodynamic variables were evaluated at 3, 6, 9 min after the start of each infusion. RESULTS: Felypressin caused reductions in CBF and inner layer PmO2 (int-PmO2). Decreases in CBF (-23%, P< 0.05) and int-PmO2 (-8%, P<0.05) observed at low dose (0.15 1U x hr(-1)) were not accompanied by changes in BP and HR. Negative correlations between cumulative doses of Felypressin (mIU x kg(-1)) and CBF (% change from base line) (r = -0.69, P<0.05) or int-PmO2 (% change from base line) (r = -0.48, P<0.05) were observed. CONCLUSION: Felypressin reduced PmO2 along with minimal changes in HR and BP.

Anesthesia↗

PubMed1999

Differences of genetic effects for the development of allergic diseases in two cities of Japan.

BACKGROUND: Differences in the effects of genetic factors on allergic diseases in two areas of the same race within the same country have not been studied with multiple logistic regression. OBJECTIVE: To determine whether the effects of genetic factors on allergic diseases differ between two areas. METHODS: A questionnaire provided information about family histories of allergic diseases and environmental factors was distributed to children attending kindergarten, elementary, or junior high school in two Japanese cities: Gifu, with a temperate climate, and Itoman, with a subtropical one. The number of subjects analyzed were 1,243 in Gifu and 1,953 in Itoman. Multiple logistic regression analysis was performed with SAS. RESULTS: Multiple logistic regression analysis showed that in both cities children of families with allergic histories have significantly higher risk of contracting allergic disease and atopic dermatitis, even after being controlled for environmental factors. In Gifu, in families where both parents suffered from allergy, there was a higher incidence of allergic diseases than when only one of the parents was suffering from it. On the other hand, in Itoman there were no differences of relative risk between paternal history and maternal history. CONCLUSIONS: We speculated that there are some differences of genetic factors between different areas of the same country, and these differences of genetic effects may influence on the difference of the prevalence of allergic diseases as well as the environmental factors.

Adolescent↗

PubMed1999

The first Japanese family with Sebastian platelet syndrome.

This report describes the first Japanese family diagnosed with Sebastian platelet syndrome. Within this family, a 6-year-old boy and 3 family members on his paternal side demonstrated thrombocytopenia with giant platelets and inclusion bodies in granulocytes, but the additional clinical features of Alport's syndrome occurring in the Fechtner syndrome were lacking. Light microscopy and ultrastructural findings of the leukocyte inclusion bodies distinguished these patients from the May-Hegglin anomaly. This family showed consistently higher levels of platelet-associated IgG (PAIgG), while surface expression of platelet membrane glycoproteins (GPIIb/IIIa and GPIb) and plasma glycocalicin levels were within the normal range. Careful observation of the giant platelet and leukocyte inclusion bodies in blood smears may help the diagnosis of this rare disease entity.

Adult↗

PubMed1998

Slow induction with sevoflurane was associated with complete atrioventricular block in a child with hypertension, renal dysfunction, and impaired cardiac conduction.

We describe the appearance of complete atrioventricular block (CAVB) with sevoflurane and nitrous oxide during the slow induction in a ten-year-old male patient with hypertension, renal dysfunction, and impaired cardiac conduction. Sinus rhythm was restored following the washout of the anaesthetic gas. And CAVB recurred after the subcutaneous injection of lignocaine. The present report shows that sevoflurane should be treated with care like other inhalational anaesthetics as regards the effect on cardiac conduction.

Anesthesia, General↗

PubMed1998

[Pilot study of relapsed osteosarcoma and brain tumor with ifosfamide, carboplatin and etoposide (ICE therapy)].

Ifosfamide, Carboplatin and Etoposide (ICE) therapy was used to treat 4 patients, 2 with refractory osteosarcoma, and one each with relapsed brain tumor and newly diagnosed brain tumor. ICE therapy was administered in doses of Ifosfamide 1,800 mg/m2 x 5, Carboplatin 400 mg/m2 x 2 and Etoposide 100 mg/m2 x 5. A total of 30 courses were administered. Two cases of osteosarcoma had a stable disease (range, 3-9 months) and 2 cases of brain tumor had a complete response by magnetic resonance imaging. Moderate or severe toxicity evaluated on a per course basis included: neutropenia 83%, thrombocytopenia 93%, fever 30%, hepatotoxicity 3%, and hemorrhagic cystitis 3%. The median time to hematologic recovery was 20 days. ICE therapy is highly effective for the treatment of refractory or recurrent solid tumors with acceptable toxicity.

Adolescent↗

PubMed1997

Cerebral cortex regional blood flow and tissue oxygen tension during the trigeminal depressor response in rabbits.

The trigeminal depressor response (TDR) is characterized with profound hypotension caused by sympathetic outflow decreases. The purpose of this study was: (1) to compare the hemodynamic changes during acute hypotension induced by the TDR with those induced by electrical stimulation of the vagal nerve (VS) as models of sympathetic inhibition and vagal activation and (2) to investigate the effects of nitrous oxide (N2O), a well-known sympathomimetic, on the hemodynamic changes during the TDR. Male Japan White rabbits were anesthetized with halothane in oxygen and mechanically ventilated. The electrode pair for the TDR was inserted into the submucosal tissue of the animal's tongue. The pair for the VS was applied to the isolated left vagal trunk. Both the TDR and the VS produced similar decreases in mean arterial pressure (MAP) and cerebral cortex regional blood flow (rCBF), although the decreases in heart rate (HR) and aortic blood flow were greater during the VS. Cerebral cortex tissue oxygen tension in both groups decreased slightly. 50% N2O, producing MAP elevation and HR decrease, ameliorated the hemodynamic changes including rCBF reduction during the TDR. A sudden diminution of sympathetic tone following noxious stimulation of the orofacial area, as in the case of the TDR, may be a possible trigger mechanism for vasodepressor reactions in dental patients. The sympathomimetic and possible antinociceptive effects of N2O may explain, at least in part, the preventive effects on vasodepressor reactions during dental procedures.

Animals↗

PubMed1997

A study of learning splice sites of DNA sequence by neural networks.

To predict of splice sites in DNA sequence, we developed a neural network system with back propagation. This system has a flexible network definition language which can describe any network structure. Three types of neural network were defined using the system for the prediction of splice sites. The neural networks are trained by the arrangements of bases around the splice sites of DNA sequences. The results of simulation showed the excellent ability of the neural networks to predict splice sites by applying and testing the arrangements of DNA sequences. This system also were used to predict the effects of point mutations on the splicing of the IX factor gene which may cause hereditary disease.

Algorithms↗

PubMed1997

Pulmonary hemosiderosis with hypersensitivity to buckwheat.

BACKGROUND: Adverse reactions after ingesting buckwheat are known to be IgE-mediated. Further, hypersensitivity reactions may be involved in some patients with pulmonary hemosiderosis related to cow milk sensitivity. We, however, encountered a patient with pulmonary hemosiderosis related to buckwheat protein without high levels of buckwheat-specific IgE antibodies. OBJECTIVE: The aim of this study was to investigate the mechanisms. METHODS: RAST for anti-buckwheat IgE, skin prick test, skin patch test, and proliferative responses of peripheral blood mononuclear cells to buckwheat were investigated in this patient. RESULTS: RAST values for buckwheat protein were negative, and skin prick test for buckwheat protein also gave negative results. On the other hand, skin patch testing for buckwheat protein elicited positive responses. Further, peripheral blood mononuclear cells of our patient responded to buckwheat protein. CONCLUSIONS: Our patient had pulmonary hemosiderosis related to non-immediate buckwheat protein hypersensitivity.

Cells, Cultured↗

PubMed1997

Combinations of IgE values and lymphocyte proliferative responses for consideration of the clinical course of infantile hen's-egg-sensitive atopic dermatitis.

We have attempted a new approach, using peripheral blood mononuclear cells (PBMCs), to predict the clinical course of infantile food-sensitive atopic dermatitis (AD). In this study, we investigated the relationships between the clinical course of infantile hen's-egg-sensitive AD and laboratory data obtained at the early stage of AD, particularly on combinations of specific IgE antibodies to hen's egg and proliferative responses of PBMCs to ovalbumin (OA). Total IgE concentrations, specific IgE antibodies to hen's egg and proliferative responses of PBMCs to OA were measured in 31 hen's-egg-sensitive AD patients within 6 months after development of AD symptoms. After the acquisition of laboratory data, the clinical courses of all patients were followed up for 1 year. The stimulation index of proliferative responses of PBMCs to OA in hen's-egg-sensitive AD patients whose symptoms did not improve was significantly (p < 0.05) higher than that in hen's-egg-sensitive AD patients whose symptoms improved. On the other hand, the radioallergosorbent test (RAST) scores for hen's egg were not statistically different between the two groups. The degree of refractoriness of AD symptoms tended to be higher in the patients who showed a higher total IgE concentration at the beginning of the clinical course than in those who showed a lower one. These results might be attributed to the underlying cause of AD, i.e., a cell-mediated and an IgE-mediated allergy. We concluded that, in addition to total IgE concentrations, combinations of RAST values and lymphocyte proliferative responses to OA are important to predict the clinical course of infantile hen's-egg-sensitive AD.

Allergens↗

PubMed1996

Interferon-gamma and interleukin-4 production of ovalbumin-stimulated lymphocytes in egg-sensitive children.

BACKGROUND: The causal relation between egg allergy and cytokines derived from lymphocytes is unknown. OBJECTIVE: Interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) production of ovalbumin-stimulated and interleukin-2 (IL-2)-stimulated peripheral blood mononuclear cells from egg-sensitive patients was investigated and compared with that of stimulated peripheral blood mononuclear cells from nonatopic healthy children. METHODS: Peripheral blood mononuclear cells from egg-sensitive patients and nonatopic healthy children were cultured with ovalbumin and IL-2 for seven days. The IFN-gamma and IL-4 concentrations in culture supernatants of the peripheral blood mononuclear cells were investigated. RESULTS: The levels of IFN-gamma production of only IL-2-stimulated or both ovalbumin-stimulated and IL-2-stimulated peripheral blood mononuclear cells from egg-sensitive patients with atopic dermatitis was significantly higher than that of healthy children and that of egg-sensitive patients with immediate allergic symptoms. CONCLUSIONS: Increased IFN-gamma production by lymphocytes after IL-2 and antigen stimulation has important implications for the mechanism of food-sensitive atopic dermatitis.

Cell-Free System↗

PubMed1995

Genetic analysis of IgE and the IGHE, IGHEP1 and IGHEP2 genes in atopic families.

The familial occurrence of allergic diseases was studied in 478 individuals and their family members. The results showed that there was pronounced familial clustering. Total serum IgE concentrations of atopic patients and their parents were well correlated. Moreover, the concentration of specific IgE of the patients and their parents was also well correlated, suggesting that IgE production was genetically determined. To determine if major structural abnormalities of IGHE, IGHEP1 and IGHEP2 genes might lead to aberrant control and subsequent increase in IgE concentration, genomic DNAs from 55 individuals, i.e., 31 atopic patients and their family members, were examined. We detected the IGHE, IGHEP1 and IGHEP2 genes in all 55 leukocyte DNAs. We could not find any large deletions or duplications in the IGHE, IGHEP1 and IGHEP2 genes of atopic patients with high serum IgE concentrations.

Adolescent↗

PubMed1995

T cell proliferation restricted by HLA class II molecules in patients with hen's egg allergy.

We investigated the synergistic effect of anti-HLA class II monoclonal antibodies on proliferative responses to ovalbumin (OA) of T cell line (TCL) cells from five hen's-egg-sensitive patients. Among the five patients, the proliferation of the TCL cells from two patients with AD who have a low immune reaction was restored by the anti-HLA-DQ monoclonal antibodies, and the proliferation of the TCL cells from the other three patients was inhibited by the anti-HLA-DP monoclonal antibodies. These results suggest that a component of the T cell repertoire reactive with OA in hen's-egg-sensitive patients may be restricted by HLA-DP molecules. Furthermore, in hen's-egg-sensitive patients with AD who have a low immune reaction, low responsiveness may be regulated by HLA-DQ molecules.

Animals↗

PubMed1995

Differences in lymphocyte proliferative responses to food antigens and specific IgE antibodies to foods with age among food-sensitive patients with atopic dermatitis.

BACKGROUND: Clinical symptoms of patients with food-sensitive atopic dermatitis often improve with increasing age. OBJECTIVE: To investigate this tendency and the underlying mechanism. METHODS: We selected and divided 194 food-sensitive atopic dermatitis patients into three age groups. The proliferative responses of peripheral blood mononuclear cells (PBMCs) to food antigens and specific IgE antibodies to foods then were evaluated with respect to age. We also followed up 55 food-sensitive patients with atopic dermatitis and examined their improvement ratio after 1 year. Further, we investigated changes in lymphocyte proliferative responses to food antigens and specific IgE antibodies to foods in food-sensitive patients with atopic dermatitis during elimination diets. RESULTS: Proliferative responses of PBMCs to ovalbumin of patients in the over 6-years-old group were significantly (P < .05) lower than those of the less than 1-year-old group. Proliferative responses of PBMCs to bovine serum albumin of patients in the over 6-years-old group were significantly (P < .05) lower than those in the 1 to 5-year-old group and in the less than 1-year-old group. RAST values for hen egg in the over 6-years-old group were significantly (P < .05) lower than those for the less than 1-year-old group. Improvement was shown by 13 of the 33 hen egg-sensitive patients with atopic dermatitis, an improvement ratio of 39%, and by 9 of the 22 cow milk-sensitive patients with atopic dermatitis, an improvement ratio of 41%. Proliferative responses of PBMCs to food antigens in food-sensitive patients with atopic dermatitis decreased rapidly after patients were placed on elimination diets. CONCLUSION: The PBMC proliferative responses to food antigens and RAST values were higher for young children and lower for older ones who suffered from food-sensitive atopic dermatitis. Oral tolerance, in addition to the development of digestive and absorptive functions, may be responsible for these immunologic changes.

Adolescent↗

PubMed1995

Prevalence of and risk factors for allergic diseases: comparison of two cities in Japan.

BACKGROUND: Differences in the prevalence of allergic diseases and the effects of genetic and environmental factors on these diseases in two areas of the same country have not been examined by multiple logistic regression. OBJECTIVE: To determine whether the effects of genetic and environmental factors on allergic diseases differ between two areas. METHODS: A questionnaire was distributed in March 1991 to children less than 16 years old attending kindergarten, elementary, or junior high school in two Japanese cities; Gifu, with a temperate climate, and Itoman, with a subtropical one. The number of subjects analyzed were 1243 in Gifu and 1953 in Itoman. Multiple logistic regression analysis was performed using SAS. RESULTS: The prevalence of allergic diseases and atopic dermatitis in Gifu were significantly higher than in Itoman (P < .05). In contrast, the prevalence of bronchial asthma in Itoman was significantly higher than in Gifu (P < .05). Multiple logistic regression analysis showed that in both cities children of families with allergic histories have significantly higher risk of contracting an allergic disease and atopic dermatitis. The prevalences of allergic diseases and atopic dermatitis were higher in Gifu than in Itoman, even after being controlled for genetic and environmental factors. CONCLUSIONS: The increased risk of contracting an allergic disease and atopic dermatitis for the children in Gifu may be due to such factors not included in the study as climate, eating habits, or the level of air pollution.

Adolescent↗

PubMed1994

A general purpose neural network simulator system for medical data processing.

We developed a general purpose neural network simulator system for medical data processing. This system has a flexible network definition language. Users can define arbitrary hierarchical neural networks using the definition language to analyze medical data that contains some complex patterns. The learning algorithm used in this system is back propagation. Learning curves are displayed on multiple windows. This is a general purpose system, so it can be used for various kinds of medical data processing such as one dimensional signal processing or two dimensional image processing. The system can run on a standard UNIX workstation, which is faster and more powerful than most personal computers. The system needs an X window system/Motif and C compiler. These are standard system programs already available on most UNIX workstations. The source code of the system can be retrieved from our anonymous ftp site via Internet.

Algorithms↗