Biomedical subjects

K Maeda

Publications and source records attributed to K Maeda.

At least 469 records · Page 26Linked to original sources

PubMed1997

Characterization of rat CD80 and CD86 by molecular cloning and mAb.

The CD28/B7 pathway provides a critical co-stimulatory signal for T cell activation. In the present study, we cloned rat CD80 and CD86 cDNA from a HTLV-1-transformed rat T cell line, Lewis-S1, expressing a high level of CTLA-4-Ig binding proteins. The predicted CD80 and CD86 polypeptides were composed of 321 and 313 amino acids respectively, and exhibited features common to human and mouse B7 family proteins. Both CD80 and CD86 mRNAs were abundantly detected in HTLV-1-transformed rat T cell lines but not in a thymic lymphoma cell line. To further explore the function of rat CD80 and CD86, we generated cDNA transfectants and anti-rat CD80 (3H5) and anti-rat CD86 (24F) mAb. Rat CD80 or CD86 transfectants exhibited a potent co-stimulatory activity for rat T cell proliferation, which was blocked by 3H5 and 24F mAb respectively. 3H5 or 24F immunoprecipitated a 80-90 or 90-100 kDa surface protein from Lewis-S1 cells. HTLV-1-transformed rat T cell lines expressed high levels of both CD80 and CD86 as estimated by staining with 3H5 and 24F, which acted co-stimulatory for allogeneic T cell activation as estimated by blocking with 3H5 and 24F. These mAb will be useful for investigating the pathophysiological functions of CD80 and CD86 in transplantation, autoimmune diseases and HTLV-1-associated pathologies in the rat system.

Amino Acid Sequence↗

PubMed1997

Oxidation conspires with glycation to generate noxious advanced glycation end products in renal failure.

The causes of long-term complications of uraemia are yet to be fully elucidated. It has recently been demonstrated that renal failure is associated with a dramatic elevation of advanced glycation end products (AGEs). These products are the result of the non-enzymatic Maillard reaction linking a protein amino group with a glucose-derived aldehyde group. A mild rise of AGEs is associated with normal ageing. Proteins with a slow turnover such as matrix proteins are thus modified and removed by an AGE-specific receptor-mediated process thought to be a part of normal tissue remodelling. A more striking rise of AGEs is observed in diabetic patients as a result of sustained hyperglycaemia. A greater variety of proteins is thus modified leading to tissue damage through alteration of tissue protein structure and function, stimulation of several cellular responses, or generation of reactive oxygen species. In uraemia, the rise of AGEs is even more marked than in diabetics and is associated with a variety of tissue disorders including vascular damage, dyslipidaemia, and beta 2-microglobulin amyloidosis. AGE accumulation in uraemia does not result from hyperglycaemia. Identification of its cause as well as of the involved precursors should contribute to the understanding of uraemic toxicity and open new therapeutic approaches. In this presentation, we propose the hypothesis that AGE generation is enhanced by an increased oxidative stress associated with uraemia. Under these conditions, a variety of compounds, both related and unrelated to glucose, may contribute to the advanced glycoxidation of proteins. In uraemia, AGEs could be taken as a marker of oxidative stress damage to proteins.

Glycation End Products, Advanced↗

PubMed1997

Survival in long-term haemodialysis patients: results from the annual survey of the Japanese Society for Dialysis Therapy.

The prognosis for haemodialysis patients is reported to be more favourable in Japan than in Europe or North America. Consequently, evaluation of the death predictors for haemodialysis patients in Japan is of considerable interest outside Japan. The Patient Registration Committee of the Japanese Society for Dialysis Therapy annually surveys the individual patient case mix, laboratory data and important events occurring in the previous years. Thus, using case mix data and laboratory data (including Kt/V and protein catabolic rate) from the 1993 questionnaire survey and the individual patients' life/death statistics from the 1994 questionnaire survey, a logistic regression analysis was conducted on 53867 patients. The analysis indicated that important death risk predictors were: (i) advanced age, (ii) occurrence of diabetes mellitus, (iii) male sex, (iv) Kt/V lower than 1.8, (v) haemodialysis time less than 5 h, (vi) protein catabolic rate less than 0.9 g/kg/day, and (vii) percentage body weight decrease less than 4% and more than 8% during the first haemodialysis session of the week.

Adult↗

PubMed1997

Current status of renal replacement therapy in Japan: results of the annual survey of the Japanese Society for Dialysis Therapy.

Beginning in 1966, the Patient Registration Committee of the Japanese Society for Dialysis Therapy has conducted a survey once a year on renal replacement therapy in Japan. As of 1983, the survey covered the life/death of patients in the survey years, as well as the case mix of individual patients. In 1990 several laboratory variables were added to the survey items. The present report summarizes the data from the 1993 and 1994 surveys. The Committee mailed out questionnaire forms at the end of the survey year to the heads of all dialysis facilities. Survey forms were returned from 99.6% of the dialysis facilities in the 1993 survey, and from 99.8% of the facilities in the 1994 survey. Some 143709 patients were treated by renal replacement therapy in 1994 (7509 were treated by CAPD, and 131016 by extracorporeal haemopurification). The gross mortality rate was 9.5% in the same year. The mean values of the laboratory variables among 88693 patients undergoing thrice weekly haemodialysis were as follows in 1993: Kt/V, 1.31 +/- 0.30; protein catabolic rate, 1.04 +/- 0.30 g/kg/day; haemodialysis time, 4.12 +/- 0.50 h. In 1994, the variables were: predialysis serum creatinine concentration, 11.54 +/- 2.85 mg/dl; predialysis serum albumin concentration, 3.91 +/- 0.55 g/dl; predialysis haematocrit, 28.69 +/- 4.36%.

Aged↗

PubMed1997

Expression of aromatase cytochrome P450 protein and messenger ribonucleic acid in human endometriotic and adenomyotic tissues but not in normal endometrium.

To determine whether local estrogen production takes place in endometriotic or adenomyotic tissues, in eutopic endometrium from patients with endometriosis or adenomyosis, and in normal endometrium, tissue specimens were examined by immunohistochemistry, catalytic activity, and mRNA expression for aromatase cytochrome P450 (P450arom). P450arom was immunohistochemically localized in the cytoplasm of glandular cells of endometriotic and adenomyotic tissues, and of eutopic endometrium from patients with the respective diseases, whereas estrogen receptors and progesterone receptors were localized in the nuclei of the glandular cells and stroma. Aromatase activity in the microsomal fraction of adenomyotic tissues was inhibited by the addition of danazol, aromatase inhibitors, and anti-human placental P450arom monoclonal antibody (mAb3-2C2) in a manner similar to such inhibition in other human tissues. Reverse transcription polymerase chain reaction and Southern blot analysis also revealed P450arom mRNA in these tissues. However, neither P450arom protein activity nor mRNA was detected in endometrial specimens obtained from normal menstruating women with cervical carcinoma in situ but without any other gynecological disease. These results suggest that at a local level, endometriotic and adenomyotic tissues produce estrogens, which may be involved in the tissue growth through interacting with the estrogen receptor.

Adult↗

PubMed1997

Mapping of antigenic sites involved in neutralization on the capsid protein of feline calicivirus.

In order to locate amino acid residues involved in the formation of feline calicivirus (FCV) neutralizing epitopes, we analysed the capsid protein gene of monoclonal antibody neutralization-resistant variants of FCV. Amino acid substitutions in the variants were identified in the two hypervariable regions of the capsid protein. Four linear and two conformational epitopes were located in the regions from residues 426 to 460 and 490 to 520, respectively. The relative positions of individual epitopes agreed with our previous antigenic analysis. Two antigenic sites composed of the neutralizing epitopes were mapped in the hypervariable regions of the capsid protein, demonstrating that a relationship exists between the genetic variability and antigenic differences in the neutralization of FCV.

Animals↗

PubMed1997

Replication of feline syncytial virus in feline T-lymphoblastoid cells and induction of apoptosis in the cells.

Feline syncytial virus (FSV) was isolated from feline peripheral blood mononuclear cells of FSV-seropositive cats. When the susceptibility of feline T-lymphocytes to FSV was examined using three strains of FSV, FSV antigens were detected in the FSV-infected T-lymphoblastoid cells. Further, a diversity of biological properties, including replication kinetics and syncytia formation, was noted among the strains, and condensation of chromatin and the fragmentation of cellular DNA were observed in the infected cells. From these data, we conclude that FSV is lymphotropic and can induce apoptosis in the lymphocytes.

Animals↗

PubMed1997

Malignant fibrous histiocytoma of the cecum: report of a case and review of the literature.

Malignant fibrous histiocytoma (MFH) of the gastrointestinal tract is extremely rare. Here we report a case of MFH of the cecum and review other cases of large bowel MFH in the literature. A 64-year-old man had a large tumor mass in the cecum associated with multiple small peritoneal implants. Histologically, most of the lesion showed inflammatory pseudotumor-like appearance; that is, a mixed proliferation of fibroblasts and myofibroblasts loosely arranged in sweeping fascicles or whorled structures and an admixture of chronic inflammatory cell infiltrate. The myofibroblastic nature of the spindle-shaped cells was confirmed by their immunohistochemical and ultrastructural findings. In addition, there was atypical histiocytic cells infiltrate in some areas and marked lymphatic involvement and lymph node metastasis by such histiocytic cells. These features were interpreted as MFH, although it had to be distinguished from inflammatory fibrosarcoma and leiomyosarcoma. The differential diagnosis is discussed here.

Actins↗

PubMed1997

New method to calculate creatinine generation rate using pre- and postdialysis creatinine concentrations.

The creatinine (Cr) generation rate reflects the muscle mass, a possible indicator of protein nutritional status. Thus, in this study, we developed equations for calculating the Cr generation rate. Depner and Daugirdas recently developed a method for determining the protein catabolic rate (PCR) from the pre- and postdialysis blood urea nitrogen concentrations. We modified their method to develop equations for calculating the total Cr generation rate from the measured predialysis Cr concentration and estimated postrebound concentration. The total Cr generation rate is defined as the sum of the intrinsic Cr generation rate and the extrinsic Cr generation rate (i.e., the generation rate of Cr derived from food). In the present study, the postrebound Cr concentration was estimated on the basis of postdialysis Cr concentration and the K/V for Cr. The intrinsic Cr generation rate was obtained by subtracting the extrinsic Cr generation rate, which was estimated on the basis of the PCR, from the total Cr generation rate calculated. The intrinsic Cr generation rate determined with this method was virtually the same as that obtained using the postrebound Cr concentration, the concentration immediately before the next hemodialysis (HD) session, and the PCR. The intrinsic Cr generation rate determined with the present method did not vary with changes in the HD prescription (i.e., with an increase in blood flow rate, a prolongation of the HD duration time, or a change in dialyzer membrane area). The present study also indicated that the intrinsic Cr generation rate decreased with age in both males and females.

Adult↗

PubMed1997

CD56-positive (nasal-type T/NK cell) lymphoma arising on the skin. Report of two cases and review of the literature.

Several authors have reported cases of patients with malignant lymphoma with unique characteristics, designated nasal-type T/NK cell lymphoma, which expresses the natural killer (NK) cell marker and shows frequent extra-nodal involvement and poor prognosis. We report 2 cases of this type of lymphoma which were CD56-positive and showed a histopathologically angiocentric pattern with cutaneous and subcutaneous tumorous lesions. Patient 1 had extensive invasion of skin, underlying skeletal muscle, spleen and bone marrow, and died of sepsis 34 months after onset. Patient 2 had multiple subcutaneous nodules and invasion to mammary gland, lung, lymph node and spleen at the time of her first visit. She died of a rapid invasion of lymphoma cells to the liver 5 months after onset. Both patients showed similar immunophenotypes of tumor cells (CD2+, CD3-, CD4-, CD8-, CD20-, CD56+) and germ line configuration of the heavy chain of immunoglobulin (JH), T-cell receptor C beta-1 subunit DNA and T-cell receptor J gamma subunit DNA. Epstein-Barr virus early regions RNA was demonstrated in the nuclei of tumor cells of both patients with in situ hybridization. The histopathological examination of the skin lesions of both patients revealed the features of angiocentric lymphoma. The detection of CD56 in the tumor cells of cutaneous lymphomas should be routinely performed for the early diagnosis of this type of lymphoma with extremely poor prognosis.

Antigens, CD↗

PubMed1997

Establishment of a murine model for metastasis of cytokine-producing tumor to the brain.

The A375 cell line, derived from human malignant melanoma, has characteristics of interleukin-6 (IL-6) production. By using this cell line, we have investigated a murine metastasis model of IL-6-producing tumors to the brain by injecting A375 cells directly into the left cardiac ventricle. Nude mice were anesthetized with intraperitoneal injection of pentobarbital sodium. Next, A375 cells suspended in phosphate-buffered saline (PBS) were injected into the left cardiac ventricle of mice. An intracardiac injection of 10(5) cells developed tumor colonies in the brain after 4 to 6 weeks. Metastatic cells were found in every lobe of the brain. An immunocytochemical study revealed IL-6 production by A375 cells at the metastatic sites in the brain. By the transfection of genes encoding proteins into A375 cells, a novel model of protein expression in the brain in vivo could be constructed. Our system does not require great skill. Our experimental model will facilitate future studies of the local effects of proteins in the brain.

Animals↗

PubMed1997

Immunohistochemical examination of the distribution of macrophages and CGRP-immunoreactive nerve fibers in induced rat periapical lesions.

To clarify the role of calcitonin gene-related peptide (CGRP) in the development of periapical lesions, we examined the distribution of CGRP-immunoreactive (IR) nerve fibers and macrophages, and the behavior of bone tissues in experimentally induced rat periapical lesions by immunohistochemical and quantitative methods. Although no extensive changes were observed at 7 days after pulp exposure, CGRP-IR nerve fibers increased in number until 28 days with a decrease thereafter. These neural changes were closely correlated with the alteration in number of macrophages except on day 7 when macrophages were significantly increased in number as compared with control rats. Tissue repair began to take place and a decrease in number of osteoclasts was observed when the density of CGRP-IR nerve fibers reached a peak. These results suggested that there might be a close relationship between macrophages and CGRP-IR nerve fibers and that CGRP-IR nerve fibers might participate in tissue repair in experimentally induced rat periapical lesions.

Animals↗

PubMed1997

Melanocyte-stimulating properties of secretory phospholipase A2.

Phospholipase A2 (PLA2) catalyzes the release of free fatty acids from membrane phospholipids, and its products derived from these fatty acids, such as prostaglandins and leukotrienes, significantly up-regulate the key melanogenic enzyme, tyrosinase, in melanocytes. This has led to suggestions that PLA2 itself triggers melanin synthesis in melanogenesis following UV irradiation or inflammation. We have examined the effect of secretory PLA2 (sPLA2) on melanogenesis in cultured human melanocytes. Secretory PLA2 stimulated DNA synthesis and melanin synthesis, and these phenomena were completely inhibited by treatment with a phospholipase inhibitor, p-bromophenacyl bromide, demonstrating that the catalytic activity of sPLA2 is required for melanogenesis. Secretory PLA2 also stimulated tyrosinase activity, increased the amount of tyrosinase-related protein-1 and up-regulated the expression of both mRNA. These findings suggest that sPLA2 is an important mediator of UV-induced or postinflammatory pigmentation.

Cells, Cultured↗

PubMed1997

[Campylobacter jejuni enteritis in three patients with HIV infection].

Gatrointestinal symptoms, which include diarrhea, are as common as respiratory symptoms in patients with HIV infection. Gastrointestinal symptoms may result from infections, neoplasma, HIV enteropathy or drug toxicity. Three HIV-infected patients admitted to our hospital complaining of diarrhea and fever. We confirmed their diagnosis as Campylobacter jejuni enteritis by bacteriological examination of their feces. All of them had eaten inadequately cooked meat in restaurants before the onset of their enteritis. Their symptoms immediately improved after the administration of antimicrobial agents. One strain of C. jejuni isolated in our cases, however, was resistant to ofloxacin. This case report suggests that we must counsel HIV-infected patients to avoid inadequately cooked food and observe resistant patterns of C. jejuni to antimicrobial agents in Japan in the future.

AIDS-Related Opportunistic Infections↗

PubMed1997

[Analysis of prognosis of bronchopulmonary infectious disease with lung cancer].

Bronchopulmonary infection affects the prognosis of lung cancer patients. Thus, we investigated the relationship between the prognosis of bronchopulmonary infectious diseases and their causative bacteria isolated by transtracheal aspiration (TTA) in lung cancer patients. In the present study, we determined which factor is more predisposing for the outcome of bronchopulmonary infections, the type of causative bacteria or the host nutritional status. A total of 107 lung cancer patients, which consisted of 105 males and 5 females (mean age 67.3 +/- 8.0), were included in this study. The study was conducted from 1981 to 1994. They were classified into the survival group and the deceased group. Causative agents of infection were compared between these 2 groups. S. pneumoniae, alpha-Streptococcus sp., M. catarrhalis, and Neisseria sp. were predominant in organisms isolated from TTA-specimens of lung cancer patients with bronchopulmonary infections, regardless of prognosis. Nutritional status, as determined by serum levels of cholinesterase, albumin, and cholesterol, was poor in the deceased group than in the survival group. These results indicate that the outcome of bronchopulmonary infections in lung cancer patients are affected mainly by the nutritional status of the host.

Aged↗

PubMed1997

[The evaluation of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-alpha) level in peripheral blood of patients with chronic lower respiratory tract infection].

In the present study, we assessed the serum level of IL-6 and TNF-alpha by ELISA in patients with chronic lower respiratory tract infection. The serum levels of IL-6 and TNF-alpha of patients in acute exacerbation phase are higher than that of in stable phase. We also classified patients in acute exacerbation phase into two groups according to the microorganism of persistent infection. The serum level of IL-6 and TNF-alpha in the patients with persistent infection with Pseudomonas aeruginosa were higher than that with Haemophilus influenzae. Moreover, the serum level of IL-6 and TNF-alpha were found to be related with malnutrition which assessed by clinical indices such as the serum level of albumin and cholinesterase. The present result suggests that IL-6 and TNF-alpha may have relationship with not only inflammation in airway but also indices of nutrition in patients with chronic lower respiratory tract infection.

Acute-Phase Reaction↗

PubMed1997

[Prognostic analysis of sepsis in patients with lung cancer].

Sepsis is one of the most serious infections occurring in patients with lung cancer. Thus, we determined what is most predisposing factor in prognosis of sepsis in lung cancer patients; the type of causative bacteria, neutropenia or host nutritional status. A total of 27 lung cancer patients with sepsis, which consisted of 23 males and 4 females (mean age 70.7 +/- 6.6), were included in this study. The study was conducted from 1991 to 1995. All subjects were classified into the survival group and the dead group. Staphylococcus aureus or Esherichia coli most frequently isolated from the blood of the patients in the survival group, while either E. coli alone or multiple organisms were predominant in the dead group. Neutropenia did not affect the outcome of sepsis in lung cancer patients. In contrast nutritional status, as determined by serum albumin levels, was closely related to the mortality in septic lung cancer patients. These results predict that the prognosis of sepsis is dependent on nutritional status of lung cancer patients.

Aged↗

PubMed1997

[A case of multiple muscular abscesses of the lower limbs by Staphylococcus aureus after chemotherapy for lung cancer].

A 67-year-old male was admitted to our hospital because of lung cancer and interstitial pneumonia. Cisplatin, vindesie and mitomycin C were administered for treatment of lung cancer. The leucocyte-counts declined to 1700/microliter on the eighth day after the chemotherapy. Though granulocyte colony-stimulating factor was administered, pain in the right thigh and high grade fever developed. Because Staphylococcus aureus was isolated from the blood specimen, piperacillin was administered. But the high grade fever continued and the pain was expanded to the right hip, left hip, thigh and leg. Because a computed tomograph of the lower limbs showed low density areas in bilateral gluteus maximus muscle right adductor magnus muscle, left biceps femoris muscle and left soleus muscle and the culture of an aspirate from abscess of right leg detected S. aureus, multiple muscular abscesses of the lower limbs was confirmed. We changed the antibiotics from PIPC to imipenem/cilastatin and minocycline on nineteenth day after the chemotherapy. His symptoms improved after the change of antibacterial agents. But he died of acute exacerbation of interstitial pneumonia, after about two months of the chemotherapy. Muscular abscesses of the limbs are very rare in Japan. Only four cases with muscular abscess of the limbs were reported in Japan, since 1988. This case suggests that a muscular abscess must be considered in the differential diagnosis of fever in patients with neutropenia.

Abscess↗