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Biomedical subjects

M Kodama

Publications and source records attributed to M Kodama.

At least 217 records · Page 12Linked to original sources
PubMed1996

Synthesis and blood compatibility evaluation of segmented polyurethanes based on cholesterol and phosphatidylcholine analogous moieties.

New segmented polyurethanes based on cholesterol and phosphatidylcholine analogous moieties were synthesized. The soft segments used in this study were the poly(butadiene), poly(isoprene) or hydrogenated poly(isoprene) glycols; the hard segments of these segmented polyurethanes were composed of 4,4'-methylenediphenyl diisocyanate, 2-[bis(2-hydroxyethyl)methylammonio]ethyl 5-cholesten-3 beta-yl phosphate and 1,4-butanediol. The blood compatibilities of synthesized segmented polyurethanes were evaluated by platelet-rich plasma contact studies and scanning electron microscopy observation using glass as the reference. The results show that the blood compatibilities of the synthesized segmented polyurethanes have great difference between the glass contact side and air exposed side for the same cast films. Generally, the hydrogenated poly(isoprene)-based segmented polyurethane is the best surface in terms of platelet adhesion, and the morphology of adhered platelets undergoes the lowest degree of variation among the segmented polyurethanes investigated in this study.

Biocompatible Materials↗
PubMed1996

Demonstration by reverse transcription-polymerase chain reaction of multiple cytokine mRNA expression in bovine alveolar macrophages and peripheral blood mononuclear cells.

The expression of the mRNAs of the cytokines interleukin (IL)-1 alpha, IL-1 beta, IL-2, IL-4, IL-6, interferon (IFN) gamma, tumour necrosis factor (TNF) alpha, and granulocyte-macrophage colony-stimulating factor (GM-CSF) was demonstrated by the reverse transcription-polymerase chain reaction (RT-PCR) in bovine alveolar macrophages (AMs) and peripheral blood mononuclear cells (PBMCs). By the use of the RT-PCR, a specific and highly sensitive technique has been developed to analyse simultaneously the array of cytokine messenger RNAs in bovine AMs and PBMCs. AMs stimulated with lipopolysaccaride (LPS) for four hours in vitro expressed IL-1 alpha, IL-1 beta, IL-6, TNF alpha and GM-CSF; PBMCs stimulated with LPS for four hours expressed IL-1 alpha, IL-1 beta, IL-6, TNF alpha and GM-CSF and when stimulated with concanavalin A (ConA) expressed IL-2, IL-4, IFN gamma and GM-CSF efficiently.

Animals↗
PubMed1996

Antimicrobial activities of iodinated polystyrene derivatives.

The antimicrobial activities of insoluble halogenated acetamidomethy1-styrene polymers (prepared by covalent bonding of iodine to polystyrene) were assessed as were the factors determining antimicrobial efficacy. The most active materials were selected from chlorinated or iodinated polymers. Antimicrobial activities were assessed for Escherichia coli (ATCC 25922; American Type Culture Collection, Rockville, MD, U.S.A.), Saccharomyces cerevisiae, and Candida albicans by determining time-course changes in microbial counts in vitro. A 2-iodoacetamidomethylstyrene polymer (No.6-I:-CH2I) was found to have the greatest antimicrobial activity against both bacteria and fungi. No.6-I is the first antimicrobial material that did not make an inhibition hollow in the conventional diffusion test or for which conjugated iodine showed antibacterial activity. This material can be introduced into styrene units on the surface of devices by chemical modification. This material was most active at 37 degrees C. For coated dishes, antimicrobial activity depended on the depth or swollen character of the reactive layer. NO.6-I requires not only a minimum width of polymer layer, but also frequent contact with microbes to have an antimicrobial effect. No.6-I is valuable as a new material because it has strong antimicrobial activity by itself but does not release active iodine. This material is expected to have various applications in implantable clinical devices.

Anti-Infective Agents, Local↗
PubMed1996

Diurnal heart rate variability in healthy subjects: effects of aging and sex difference.

To study the effects of aging and gender, circadian profiles of heart rate variability were evaluated for 105 healthy volunteers by frequency domain analysis of a Holter electrocardiogram record. The low-frequency (LF) component representing cardiac beta-adrenergic function showed high values for the 0800-1200 period in male subjects and the 1200-2400 period in female subjects. The high-frequency (HF) component representing parasympathetic function showed a peak for the 0000-0600 period in both male and female subjects independent of age. Male subjects showed significantly higher %LF [LF/(LF + HF) x 100] than female subjects. LF showed consistently highly significant correlation with age. These basic findings can help elucidate the diurnal profile of cardiac nerve function and how it is affected by aging and sex difference.

Adult↗
PubMed1996

Analysis of heart-infiltrating T-cell clonotypes in experimental autoimmune myocarditis in rats.

Experimental autoimmune myocarditis (EAM) resembles the lethal giant cell myocarditis seen in humans, and the recurrent forms lead to dilated cardiomyopathy (DCM). EAM in rats induced by a subcutaneous injection of cardiac myosin has been shown to be a T cell-mediated autoimmune disease. Alpha beta T cells have proved to be important by the observation that antibodies to alpha beta T-cell receptor (TCR) prevent disease progression. Alpha beta cells recognize antigenic peptides bound to major histocompatibility (MHC) molecules by alpha beta TCR, and complementarity determining region 3 (CDR3) is considered the most important region for antigen recognition. To elucidate the nature of this T cell-mediated myocarditis, we analyzed TCR V beta chains of heart-infiltrating T cells. In the early state of EAM, none of 22 TCR V beta chain transcripts seemed to be dominant by reverse transcription-polymerase chain reaction analysis of total RNA and flow cytometric analysis. On the other hand, single-strand conformation polymorphism analysis of TCR V beta 8.2, V beta 8.5, V beta 10, and V beta 16 cDNA amplified by polymerase chain reaction encompassing the CDR3 revealed oligoclonal expansion in heart-infiltrating T cells isolated from animals at various disease stages. cDNA encoding V beta CDR3 from heart-infiltrating and pericardial effusion T cells in rats with EAM revealed more restricted sequences than did cells from rats with normal spleens. Clones from distinct lesions of the same animal were identical, and clones from heart-infiltrating and pericardial effusion T cells from the same animal showed overlap. Thus, CDR3 of the TCR beta chain may be important in rat EAM, and heart infiltrating T cells are considered to recognize the specific antigen.

Amino Acid Sequence↗
PubMed1996

A new haemocompatible phospholipid polyurethane based on hydrogenated poly(isoprene) soft segment.

A new haemocompatible phospholipid polyurethane based on hydrogenated poly(isoprene) glycol (HPIP) and 4,4'-methylendiphenyl diisocyanate (MDI) was synthesized using 2-[bis(2-hydroxyethyl)methyl-ammonio]ethylstearylphosphate (BESP) and 1,4-butanediol (BD) as chain extender. The bulk and surface characteristics of this material was investigated by differential scanning calorimetry (DSC), dynamic viscoelasticity and tensile property measurements, attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and contact angle measurement. This polymer possessed a hydrophobic surface revealed by contact angle measurement. The haemocompatibility of this polyurethane was evaluated by platelet rich plasma (PRP) contacting studies and scanning electron microscopy (SEM) observation using medical grade poly(vinyl chloride) (PVC) as the reference. The results show that this new polyurethane had relatively lower platelet adhesion and limited shape change for the attached platelets compared to PVC. The clotting time of the materials in contact with platelet poor plasma (PPP) was 99, 75, and 62 s and in contact with PRP was more than 240, 100, and 86 s for new polyurethane, PVC, and glass, respectively. This new phospholipid polyurethane is expected to have wide applications as coating or structural material for blood-contacting medical equipment due to its outstanding haemocompatibility and excellent mechanical strength.

Biocompatible Materials↗
PubMed1996

[TNF-alpha gene therapy for nonimmunogenic tumor using immunogenic variant induced with mutagen (N-methyl-N'-nitro-N-nitrosoguanidine)].

We have already reported that a combination of TNF-alpha and immunogenic variant was effective for immunotherapy of nonimmunogenic tumor. Immunogenic variants (A2 and A7) were obtained from nonimmunogenic fibrosarcoma (parent cell: 1767-3) by mutagen treatment with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). In this study, we studied about the possibility of TNF-alpha gene immunotherapy for nonimmunogenic tumor. We established two types of TNF-alpha producing cell lines. One is TNF-alpha producing nonimmunogenic variant (1767 TR 2), and another is TNF-alpha producing immunogenic variant (A7 TR3). We compared them about the ability of producing specific immunity against parent tumor. TNF-alpha producing immunogenic variant (A7TR3) could induce strong specific immunity to parental cell compared to TNF-alpha producing nonimmunogenic variant (1767TR2). Immunogenicity of tumor is very important when we want to perform TNF-alpha gene immunotherapy against cancer.

Animals↗
PubMed1996

Mitochondrial biosynthesis controls the sensitivity of Chinese hamster cells to hydrogen peroxide.

The mechanism of H2O2-resistance of Hpr-4, a variant of Chinese hamster V79 cells, was investigated. The effect of H2O2 on the mitochondria of the parental and Hpr-4 cells was compared. First, both biochemical and ultrastructural results showed that mitochondria in the parental cells were damaged by exposure to H2O2, while those in Hpr-4 cells recovered from the damage. Second, the H2O2-resistance of Hpr-4 cells was reversibly reduced or recovered by the addition or removal of inhibitors of mitochondrial biosynthesis, respectively. Third, the parental cells were auxotrophic to pyruvate after exposure to H2O2. Fourth, H2O2-sensitivity of the parental cells was also enhanced by the inhibition of mitochondrial biosynthesis. From these results, it was concluded that the mitochondria of Hpr-4 cells apparently had a greater resistance to H2O2 than those of the parental cells and that functional mitochondria were involved in the recovery of Chinese hamster V79 cells from H2O2-induced damage.

Adenosine Triphosphate↗
PubMed1996

[A clinical study of recurrent breast cancer].

In a recent 14-year period from December 1978 to December 1993, 180 patients with breast cancer were treated at the hospital, and out of these 180 patients, 38 patients (21.1%) who had a recurrent breast cancer were clinically evaluated. The first recurrence occurred in the local skin in 13 patients, regional lymph node in 1, bone in 13, lung in 4, liver in 4 and in other areas in 3. Histologically, the incidence of scirrhous carcinoma recurrence was higher than that of papillotubular carcinomas. There was no recurrence in mucinous carcinomas. The frequency of recurrence became higher in accordance with TNM classification, namely, 6.7% in Stage I, 23.7% in Stage II, 37.5% in Stage IIIa, and 47.1% in Stage IIIb cancers. An increasing tendency in the recurrence rate was also noted with an increase of tumor diameter or lymph node metastasis. Otherwise, there was no difference in cumulative survival after recurrence between TNM classification. There were no correlations between the estrogen receptor and incidence of recurrence or 5-year survival rate. The disease free interval (DFI) was less than 2 years in about 60% of the recurrent cases. DFI of bone metastasis was longer than for the other sites of recurrence. The survival rate increased according to prolongation of DFI. After through evaluation of these results, one should pay close attention to follow-up after mastectomy.

Adult↗
PubMed1996

[Informed consent of the esophageal cancer].

An informed consent (IC) is composed of sufficient explanation from medical providers about illness and proposed treatment and its acceptance by a patient with a principal intention to protect patients. Esophageal cancer has some characteristic features in contrast to other malignancy that is (1) high prevalence in elderly with advanced stage (2) significant malignant potential in nature (3) high surgical risk with mortality of 3% and morbidity of over 50% (4) availability of diverse treatment modality such as resection, irradiation and chemotherapy. Therefore it is highly advised for medical providers to inform patients of their diagnosis and explain anticipated surgical risks to help them understand the negative features mentioned above although extent of revelation of illness should be highly individualized according to the judgment of medical providers. It is also mandatory for medical providers to inform patients of available treatment modalities applicable according to the stage of disease and evaluated surgical risk before obtaining a consent to a proposed treatment. Illustrated figures advocate patients to further understand the stage of disease, the necessity of proposed treatment, surgical risk with anticipated complication etc, and explanatory forms if accompanied are even more helpful in this respect. An informed consent is to be signed to verify the acceptance of a proposed treatment by a patients who has been fully aware of illness. An informed consent should be utilized to establish ensured patient, doctor relationship through its make-up process instead of being considered as an exclusive legal document of agreement.

Esophageal Neoplasms↗
PubMed1996

Postoperative hypercoagulable state followed by hyperfibrinolysis related to wound healing after hepatic resection.

BACKGROUND: Coagulative disorders may result from a breakdown in the balance between coagulation and fibrinolysis. It is important to assess the relative physiologic states of coagulation and fibrinolysis related to operation. STUDY DESIGN: A prospective study of 16 patients who underwent hepatic resection was performed. Coagulative and fibrinolytic activities were examined for comparison with those of patients having total thoracoesophagectomy or colorectal resection. In addition, mice underwent hepatic resection, and histologic analysis was conducted to detect local fibrinolysis. RESULTS: In patients who underwent hepatic resection, circulating levels of thrombin-antithrombin III complex were significantly elevated during operation, whereas the levels of plasmin-alpha 2-plasmin inhibitor complex, fibrin-fibrinogen degradation products, and D-dimer were slightly elevated. After operation, the values of thrombin-antithrombin III complex decreased but plasmin-alpha 2-plasmin inhibitor complex peaked on the third postoperative day and both fibrin-fibrinogen degradation products and D-dimer increased again to reach maximum levels on postoperative day 7. Immediately after operation, the ratio of thrombin-antithrombin III complex to plasmin-alpha 2-plasmin inhibitor complex was significantly greater and the ratio of tissue-type plasminogen activator to plasminogen activator inhibitor-1 was significantly lower in patients who underwent hepatic resection than comparable ratios in patients who underwent colorectal resection. In the murine model, fibrin-like products with immunostaining of plasminogen activator inhibitor-1 were broadly deposited at the edge of the residual liver on postoperative day 5, then disappeared by postoperative day 14. CONCLUSIONS: These findings indicate that immediately after operation the stress of hepatic resection led to extensive hypercoagulation and hypofibrinolytic activity, as compared with colorectal resection, and suggest that fibrinolysis without hypercoagulation in the late postoperative period might be caused by local fibrinolysis in the healing wound.

Aged↗
PubMed1996

[A case study of metastatic renal cell carcinoma in lungs showing complete response to continuous subcutaneous injection of interferon alpha and gamma].

Previously, we reported a case of complete response (CR) of metastatic renal cell carcinoma with inhalant interferon-gamma. This inhalant therapy was considered effective against metastatic lung hilar tumors. On the other hand, metastatic tumors of the peripheral lung field tumor did not respond to the inhalation therapy. We report, a case of metastatic renal cell carcinoma in peripheral lungs showing complete response to continuous subcutaneous administration of interferon alpha and gamma. A 53-year-old woman was admitted to our hospital because of a large palpable mass in the left upper quadrant in March, 1994. Computerized tomographic (CT) scan disclosed a huge renal tumor. To reduce the tumor size, transarterial embolization, and subcutaneous administration of interferon-gamma were performed. In April 1994, the tumor was completely excised. In the post-operative course, multiple metastases were recognized in the lower peripheral lung field, subcutaneous administration of IFN-gamma and inhalation of IFN-gamma were begun, but the tumor size increased in October 1994. She underwent continuous subcutaneous administration of IFN-alpha and gamma. Three months later, the lung tumor disappeared. She has remained tumor-free as of October 1995. We concluded that this therapy may be effective against metastatic renal cell carcinoma in the lungs.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

[Treatment of superficial carcinoma of the esophagus--a review of responses to questionnaire on superficial carcinoma of the esophagus collected at the 49th conference of Japanese Society for Esophageal Diseases].

Histopathological characteristics and optimal treatment modality for superficial esophageal carcinoma were reevaluated by the way of nationwide questionnaires to the members of the Japanese Society for Esophageal Diseases. A questionnaire was designed for patients with preoperatively untreated superficial carcinoma of the esophagus who had undergone either surgical or endoscopic treatment between January 1, 1990 and December 30, 1994. As the results, the incidence of positive lymphatic invasion or lymphnode metastases tended to increase markedly as cancer infiltration reached the lamina muscularis mucosa. The majority of the cases with 0-I or 0-III components were sm. cancer. The indication of endoscopic mucosal resection (EMR) was limited to m1 and m2 superficial carcinoma in 76% of the institutions surveryed. Tumors measuring 2cm or more in diameter were resected piecemeal in 94% of the patients. The complications of EMR were observed in approximately 6.8% of patients, which denoted perforation, stenosis, and hemorrhage on most of the cases. As for the result of the treatment, almost all patients with m1 or m2 cancer survived. There was no significant difference in prognosis between m3 cancer and m1 or m2 cancer, but sm1 cancer showed worse prognosis than mucosal carcinoma. From this review, further study was advocated to refine the treatment strategy against m3 or sm1 cancer in the future.

Endoscopy↗
PubMed1996

[Atherosclerosis in subjects with mild hyperglycemia].

We have evaluated quantitatively the thickness of intimal plus median wall of the carotid arteries (IMT) in subjects with mild hyperglycemia determined by the OGTT recommendation criteria of Japanese Diabetes Association, consisting of IGT and non IGT. IMTs of IGT and non IGT hyperglycemic subjects were significantly thicker than those of normal volunteers with any decade and were quite comparable with those of diabetics. Accumulation of risk factors of atherosclerosis linearly increased IMT in subjects with mild hyperglycemia. IMT of subjects with hyperglycemia and hyperin-sulinemia after OGTT was significantly higher than that with relatively hypoglycemia and hypoinsulinemia. IMT was inversely related with insulin resistance but not with endogenous insulin secretory ability. These data indicate that insulin resistance is one of major risk factor for advancing carotid arteriosclerosis in subjects with mild hyperglycemia.

Arteriosclerosis↗
PubMed1996

[Dynamic Gd-DTPA-enhanced MR imaging in evaluation of the function of transplanted kidneys].

The purpose of the study was to evaluate the potential of dynamic Gd-DTPA-enhanced MR imaging in assessing of the function of transplanted kidneys. Dynamic MR imaging was performed using the GRASS pulse sequence in 21 subjects (56 examinations), and in each examination 30 images were obtained after a bolus injection of Gd-DTPA. Imaging findings including signal increase and/or signal drop in cortex, signal drop in medulla, and signal drop in calyces were utilized for the evaluation of renal function. Renal function was also evaluated using the following parameters: Ta, time between the initial observation of signal increase in cortex and signal drop in medulla. Tb, time between the initial observation of signal drop in medulla and in calyces; Tc, Ta + Tb, and Max. C/M, maximum ratio of signal intensity between cortex and medulla among 30 images. In the group of patients with normal graft function (Ccr > or = 60ml/min), all imaging findings were observed. In the group of patients with mild graft dysfunction (30ml/min < or = Ccr < 60ml/min), all imaging findings but signal drop in cortex were observed. The time parameters of Ta, Tb, and Tc were significantly larger, and Max. C/M was significantly smaller than those observed in the group with normal graft function. In the group of patients with severe graft dysfunction (Ccr < 30ml/min), almost none of the findings were observed. The investigation in patients in the postoperative state revealed a close correlation of the imaging findings and the values of parameters with changes in graft function over time. The results indicated the usefulness of the method in semiquantitative evaluation of graft function, including that of patients in postoperative state. This study suggests that dynamic Gd-DTPA-enhanced MR imaging could be a valuable method for the management of transplanted kidneys.

Adolescent↗