Biomedical subjects

M Maeda

Publications and source records attributed to M Maeda.

At least 271 records · Page 15Linked to original sources

PubMed1999

Bioconjugation of laminin peptide YIGSR with poly(styrene co-maleic acid) increases its antimetastatic effect on lung metastasis of B16-BL6 melanoma cells.

A comb-shaped polymeric modifier, SMA [poly(styrene comaleic anhydride)], which binds to plasma albumin in blood was used to modify the synthetic cell-adhesive laminin peptide YIGSR, and its inhibitory effect on experimental lung metastasis of B16-BL6 melanoma cells was examined. YIGSR was chemically conjugated with SMA via formation of an amide bond between the N-terminal amino group of YIGSR and the carboxyl anhydride of SMA. The antimetastatic effect of SMA-conjugated YIGSR was approximately 50-fold greater than that of native YIGSR. When injected intravenously, SMA-YIGSR showed a 10-fold longer plasma half-life than native YIGSR in vivo. In addition, SMA-YIGSR had the same binding affinity to plasma albumin as SMA, while native YIGSR did not bind to albumin. These findings suggested that the enhanced antimetastatic effect of SMA-YIGSR may be due to its prolonged plasma half-life by binding to plasma albumin, and that bioconjugation of in vivo unstable peptides with SMA may facilitate their therapeutic use.

Animals↗

PubMed1999

Quantitative analysis of cerebral microvascular hemodynamics with T2-weighted dynamic MR imaging.

The purpose of this study was to quantify cerebral microvascular hemodynamics with T2-weighted dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI) using a half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence. We performed T2-weighted DSC-MRI with HASTE sequence in 19 normal subjects. After bolus injection of gadopentetate dimeglumine, HASTE images of two sections were acquired for the simultaneous creation of concentration-time curves in the internal carotid artery and in brain tissue. Absolute regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF), and mean transit time (MTT) values of brain tissue were calculated on a base of the indicator dilution theory, and all values were corrected on the assumption that rCBF of white matter is constant in 22 mL/100 g tissue/min without age-dependent alteration. A decrease in rCBV and rCBF of gray matter was age dependent, while rCBV of white matter did not show significant change with aging. The mean rCBF value in gray matter was 37.3 +/- 8.4 mL/100 g tissue/min. The mean rCBV value was 4.1 +/- 0.8 mL/100 g tissue in gray matter and 2.9 + 0.4 mL/100 g tissue in white matter. The rCBV and rCBF values of gray and white matter obtained from T2-weighted DSC-MRI with HASTE sequence were slightly lower than the published data calculated by gradient-echo sequence. We were able to perform absolute quantifications of the capillary blood volume and flow, using a HASTE sequence, which would not have been possible with a gradient-echo sequence. This technique provides a new method for estimating cerebral microvascular hemodynamics.

Adult↗

PubMed1999

Editorial

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Journal Article↗

PubMed1999

Primary CNS lymphoma associated with streptococcal abscess: an autopsy case.

This report describes a case of streptococcal abscess in the nodules of a primary central nervous system (CNS) lymphoma. Magnetic resonance imaging (MRI) of the brain revealed multiple lesions with ringlike enhancement over the bilateral frontal, right temporal, and left parietal lobes. On admission, acute brain edema occurred following angiography, which resulted in respiratory arrest. Autopsy findings showed that the ringlike enhanced lesions on MRI were streptococcal abscesses localized in the lymphoma nodules. The lymphoma was classified as non-Hodgkin, diffuse large cells of B-cell lineage. No other lymphoma mass was found extracranially. An immunohistochemical study showed that the lymphoma cells were positive for leukocyte common antigen, Epstein-Barr virus, bax. and bcl-XL, and negative for L-26 and bcl-2. This case demonstrated that an opportunistic streptococcal abscess developed in primary CNS lymphoma in a patient without acquired immunodeficiency syndrome (AIDS), though a few similar cases have been reported in patients with AIDS.

Brain Abscess↗

PubMed1999

Hyperacute infarction: a comparison of CT and MRI, including diffusion-weighted imaging.

We compared CT and MRI obtained within the first 3 h of onset of a cerebral infarct. Echo-planar diffusion-weighted MRI delineated the infarcted areas most clearly, and subtle low-density areas on CT were consistent with those shown to be abnormal by diffusion-weighted MR. The signal changes of affected areas on fast spin-echo proton-density, T2-weighted and fast FLAIR images were subtler than the low density on CT.

Cerebral Cortex↗

PubMed1999

Quantification of osteopontin in the urine of healthy and stone-forming men.

Osteopontin (OPN) is one of the most important components in calcium stone matrix, but its role in stone formation is not clear. Since quantitative data regarding the excretion of OPN are necessary to assess its role, we have developed a quantitative enzyme-linked immunosorbent assay (ELISA) for OPN, and measured the urinary OPN concentrations in urolithiasis patients. Forty-seven men with urinary stones composed chiefly of calcium oxalate participated in the study. The controls were 13 normal healthy male volunteers. Urine samples were collected early in the morning and analyzed by a quantitative ELISA employing purified polyclonal antibodies to synthesized OPN aminopolypeptides. The urinary ratio of the concentrations of OPN and creatinine (OPN/Cre) in the urolithiasis patients (0.039 +/- 0.029) was significantly lower than that in the control subjects (0.062 +/- 0.030) (P<0.05). Single stone formers (n = 26; 0.050 +/- 0.020) had significantly higher OPN/Cre ratios compared with recurrent stone formers (n = 21; 0.031 +/- 0.021) (P<0. 05). The results show that OPN excretion in urolithiasis patients was lowered, presumably because of the incorporation of OPN by kidney stones.

Adult↗

PubMed1999

Surgical outcome of intramedullary spinal cord ependymoma.

Surgical outcome of intramedullary spinal cord ependymoma was investigated in order to define the treatment strategy. We have operated on 18 cases of intramedullary spinal cord ependymoma based on the principle of radical resection. The follow-up periods ranged from 10 months to 249 months with an average of 86.2 months. Postoperative neurological status in the long follow-up periods was compared to the pre-operative status and was correlated with the histological grade of malignancy. Total removal of the tumour was achieved in 17 cases, and subtotal removal followed by radiation therapy was conducted in 1 case. There was neither surgical mortality nor radiological evidence of recurrence in the long-term follow-up periods. The final outcome of the neurological condition was improved in 1 case, unchanged in 15 cases (including a case of subtotal removal) and deteriorated in 2 cases. The deterioration was in the form of gait disturbance due to the worsening of proprioception in 2 cases and dysaethesia in 1 case. Histological examination showed no evidence of anaplasia in 6 cases, evidence of early anaplasia in 10 cases, and moderate evidence of anaplasia in 2 cases. No relationship between the histological malignancy and clinical course was found. Intramedullary spinal cord ependymoma should be removed radically as early as possible while taking great care to avoid posterior column injury. Histologically malignant ependymoma might be a clinical exception.

Adolescent↗

PubMed1999

Unique radiological appearance of a microcystic meningioma.

A 35-year-old female presented with partial complex seizures. Computed tomography (CT) showed a slightly high density mass over the right frontal convexity, with heterogeneous contrast enhancement. T1-weighted magnetic resonance (MR) imaging showed the tumour as a hypo-intense lesion, with faint reticular enhancement after intravenous injection of gadolinium-diethylenetriaminepenta-acetic acid. The tumour was totally removed. The specimen was extremely soft and moist. The histological diagnosis was microcystic meningioma. The tumour cells were composed of typical meningothelial cells and stellate cells. The degenerative character of the tumour may be reflected in the poor enhancement on CT and MR imaging. This faint enhancement effect may be a neuro-imaging characteristic indication of this rare microcystic variant of meningioma.

Adult↗

PubMed1999

Beneficial effect of prostaglandin E1 on blood flow to the gastric tube after esophagectomy.

BACKGROUND: A prospective study on the vasodilatory effect of prostaglandin E1 on blood flow to the gastric tube after esophagectomy is reported. METHODS: Twelve patients with thoracic esophageal cancer who underwent esophagectomy were enrolled in this study. In all patients, the esophagogastrostomy was performed in the cervical region, and the stomach was used for reconstruction. Immediately after the creation of the gastric tube, baseline blood flow was measured at the oral end, in the center, and at the pyloric ring of the gastric tube using a laser Doppler flowmeter. The prostaglandin E1 group (n = 6) was then infused with prostaglandin E1 until postoperative day 2; the control group (n = 6) received saline. At +5 minutes and +40 minutes after administration, blood flow was again measured at the same three sites. RESULTS: The control group did not show a significant increase of blood flow to any site over time. For the prostaglandin E1 group, blood flow at +40 minutes increased from the baseline measurements significantly at a rate of 63%, 39%, and 36%, respectively. CONCLUSIONS: Prostaglandin E1 has a characteristic vasodilating effect on the area of impaired microcirculation of the gastric tube, thereby increasing blood flow to the affected area.

Adult↗

PubMed1999

Differences between bulimia nervosa and binge-eating disorder in females with type 1 diabetes: the important role of insulin omission.

This study explored the differences between bulimia nervosa ("BN," n=22) and binge-eating disorder ("BED," n=11) in type 1 diabetic females and the factors most predictive of poor glycemic control in patients suffering from these disorders. These two groups and a control group without eating disorders (n=32) were compared across a number of demographic, psychological, and medical variables. BN manifested significantly more severe disturbances related to eating disorders, depression, anxiety, a higher rate of co-occurring mental disorders, and poorer psychosocial functioning compared with BED. BN also showed poorer glycemic control. Multivariate analysis indicated that higher serum glycosylated hemoglobin (HbA1c) levels were most associated with the presence of severe insulin omission in type 1 diabetic females with binge eating. Clinicians may be able to determine the psychological/medical severity of illness in these patients by identifying the presence of compensatory behaviors to prevent weight gain such as severe insulin omission, as described in the DSM-IV.

Adolescent↗

PubMed1999

Correlation of telomerase activity with development and progression of adult T-cell leukemia.

Telomerase is an enzyme that adds hexameric TTAGGG nucleotide repeats to the ends of vertebrate chromosomal DNAs (i.e. telomeres) to compensate for losses that occur with each round of DNA replication. Telomerase activity, demonstrable in most human tumors, enables them to maintain telomere stability. Peripheral blood mononuclear cells were sampled from 57 patients seropositive for human T-lymphotropic virus type I (HTLV-I), including 24 asymptomatic viral carriers, ten smoldering type, five chronic type, and 18 acute type adult T-cell leukemia (ATL). Telomerase activity was determined in samples using a modified telomeric repeat amplification protocol. We semiquantitatively determined telomerase activity by serial dilution of each sample. All of 23 samples from acute and chronic type ATL patients were positive, seven of ten (70%) smoldering type patients and seven of 24 (29.2%) asymptomatic viral carriers were positive. Disease progression from asymptomatic viral carrier to acute type correlated with telomerase activity. Two samples from chronic type ATL patients with relatively high telomerase activity progressed to the acute type within 1 month. Serum lactate dehydrogenase level also correlated with telomerase activity. These results indicate that reactivation of telomerase activity is a key event in development and progression of ATL, and telomerase could be a useful marker for predicting the course of disease. Accordingly, ATL could be a good candidate disease for trials of telomerase inhibitors, as novel anticancer drugs.

Adult↗

PubMed1999

Differential gene expression of human telomerase-associated protein hTERT and TEP1 in human hematopoietic cells.

The maintenance of telomere length is crucial for the survival of cells. Recently, genes for proteins that consist of human telomerase have been cloned and the results have indicated a close relationship between telomerase activity and its gene expression. We studied the mRNA expression of the telomerase-associated genes, hTERT and TEP1, in hematopoietic cells in order to clarify the relation between them and telomerase activity using semiquantitative RT-PCR. In polymorphonuclear cells and monocytes isolated from peripheral blood, which had no detectable telomerase activity, no hTERT mRNA expression was seen. On the other hand, lymphocytes and CD34-positive cells both demonstrated hTERT mRNA expression. TEP1 mRNA was detected in all samples, showing no differential expression. We then assessed hTERT and TEP1 mRNA expression in CD34-positive cells cultured in vitro with growth factors. After 4 weeks of culture, all the cells showed myeloid differentiation and the telomerase activity was downregulated. hTERT mRNA was expressed in CD34-positive cells, but was downregulated in 4-week-cultured cells. TEP1 showed no apparent differential expression. We conclude that hTERT mRNA expression is downregulated in accordance with telomerase downregulation during the course of myeloid differentiation, which suggests that it plays a crucial role in the expression of enzyme activity, while TEP1 has a much smaller role to play, if any.

Carrier Proteins↗

PubMed1999

Effects of abdominal belts on intra-abdominal pressure, intra-muscular pressure in the erector spinae muscles and myoelectrical activities of trunk muscles.

OBJECTIVE: To evaluate the effects of abdominal belts on lifting performance, muscle activation, intra-abdominal pressure and intra-muscular pressure of the erector spinae muscles. DESIGN: Simultaneous measurement of intra-abdominal pressure, intra-muscular pressure of the erector spinae muscles was performed during the Valsalva maneuver and some isometric lift exertions. BACKGROUND: While several hypotheses have been suggested regarding the biomechanics of belts and performance has been found to increase when lifting with belts, very little is known about the modulating effects on trunk stiffness. At present, there is no reason to believe that spine tolerance to loads increases with belts. METHODS: An abdominal belt designed for weightlifting was used. Intra-abdominal pressure, intra-muscular pressure of the erector spinae muscles and myoelectric activities of trunk muscles (erector spinae, rectus abdominis and external oblique) were measured simultaneously during the Valsalva maneuver as well as three types of isometric lifting exertions (arm, leg and torso lift). A paired t-test was used to analyze for statistical differences between the two conditions (without-belt and with-belt) in intra-abdominal pressure, intra-muscular pressure of the erector spinae muscles and in the integrated EMG of the trunk muscles. RESULTS: Intra-muscular pressure of the erector spinae muscles increased significantly by wearing the abdominal belt during Valsalva maneuvers and during maximum isometric lifting exertions, while maximum isometric lifting capacity and peak intra-abdominal pressure were not affected. Integrated EMG of rectus abdominis increased significantly by wearing the abdominal belt during Valsalva maneuvers (after full inspiration) and during isometric leg lifting. CONCLUSIONS: Wearing abdominal belts raises intra-muscular pressure of the erector spinae muscles and appears to stiffen the trunk. Assuming that increased intra-muscular pressure of the erector spinae muscles stabilizes the lumbar spine, wearing abdominal belts may contribute to the stabilization during lifting exertions.

Abdominal Muscles↗

PubMed1999

Simultaneous determination of alpha-fetoprotein, human chorionic gonadotropin and estriol in serum of pregnant women by time-resolved fluoroimmunoassay.

We have developed a simple and rapid time-resolved fluoroimmunoassay (TR-FIA) for simultaneous determination of alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG) and estriol (E3) using europium and samarium ion chelate. In the proposed method, we used a combination of a 96-well microtiter plate for the AFP and hCG assay and transferable solid phase plate for the E3 assay. Therefore, these analytes could be measured simultaneously. The measurable ranges for AFP, hCG and E3 by the proposed method were 3.91-1000 ng ml(-1), 877-250000 IU l(-1) and 0.39 100 ng ml(-1), respectively. The proposed method which utilized characteristics of a rare earth ion chelate, was convenient (unnecessary diluting samples), quick (96 assays for 2 h), and required only a small quantity sample (50 microl). The principle of this proposed method is applicable to other antigens.

Antibody Specificity↗

PubMed1999

Postoperative chemo-endocrine treatment with mitomycin C, tamoxifen, and UFT is effective for patients with premenopausal estrogen receptor-positive stage II breast cancer. Nishinihon Cooperative Study Group of Adjuvant Therapy for Breast Cancer.

The effectiveness of combining mitomycin C (MMC), tamoxifen (TAM), and 1-(2-tetrahydrofuryl)-5-fluorouracil (tegafur) was evident in patients with estrogen receptor-positive (ER+) breast cancers. UFT, an oral preparation of tegafur and uracil at a molar ratio of 1:4, was reported to have higher antitumor effects than tegafur alone for patients with breast cancer. Therefore, the combined chemotherapy of MMC, TAM and UFT may possibly be effective for breast cancer. From 1988 to 1991. we studied the effects of postoperative adjuvant therapy for Japanese women with stage 11 breast cancer, all seen at 71 institutions in western areas of Japan. Five hundred and ninety four patients with stage II primary breast cancer who had undergone curative surgery, including total mastectomy and axillary lymph node dissection, were enrolled. On the day of surgery, each patient was given 13 mg/m2 of MMC intravenously. Patients with ER+ tumors were then assigned to group A or group B. Group A received 30 mg/day of TAM given orally from postoperative 2 weeks, for 2 years. Group B was additionally given an oral dose of 300 mg/day of UFT for 2 years, given concomitantly with 30 mg/day of TAM. Patients with ER- tumors were assigned to group C or group D. Group C were prescribed 300 mg/day of UFT, orally, from postoperative 2 weeks for 2 years, and group D were additionally given an oral dose of 30 mg/day of TAM together with 300 mg/day of UFT. There were no differences among the groups regarding prognostic factors or doses of MMC and TAM in ER+ patients and MMC and UFT in ER- patients. Toxicity rates for leukopenia, anorexia, and nausea/vomiting were higher in group B than in group A patients. There were no statistical differences in the overall survival and disease-free survival times between groups A and B, or groups C and D, for all eligible cases. In a retrospective subgroup analysis using Bonferroni's adjustments, the additional effect of UFT on the combined treatment of MMC and TAM lengthened the disease-free survival time for patients with premenopausal ER+ cancers (corrected P value by Bonferroni's adjustments <0.05). Multivariate analysis showed that effects of the combined treatment of MMC, TAM, and UFT was significantly related to the menopausal status (P<0.01). Our findings show that postoperative ingestion of MMC, TAM, and UFT was effective for patients with premenopausal ER+ stage II breast cancer.

Adult↗

PubMed1999

Primary culture of lymphoid organ cells and haemocytes of kuruma shrimp, Penaeus japonicus.

A primary cell culture system was developed for the cells of lymphoid organ tissue of kuruma shrimp, Penaeus japonicus. Minced tissues of lymphoid organs were seeded and incubated at 30 degrees C in medium 199 supplemented with 20% foetal bovine serum, a salt mixture and a lactalbumin hydrolysate (0.1 g/l). Fibroblast-like cells and epithelioid-like cells survived for 54 days. Cells did not survive after trypsin, collagenase or hyaluronidase treatment used for cell dissociation. Mitogens (Con A, PHA-P, Pokeweed) and insulin did not enhance cell proliferation. When penaeid rod-shaped DNA virus (PRDV) was inoculated into the lymphoid organ cell culture, a cytopathic effect was observed within 8 days. On the other hand, large granular haemocytes that were fractionated using a Percoll continuous density gradient were not infected with PRDV in vitro within 10 days, which was the longest period of haemocyte maintenance.

Animals↗

PubMed1999

Identification of an adhesion molecule expressed on adult T cell leukemia cells derived from a patient with gastrointestinal involvement: implication for a possible role of integrin beta 7 in leukemic cell infiltration into intestinal mucosa.

Patients with adult T cell leukemia (ATL) often manifest leukemic cell infiltration into various organs such as lung, liver, skin, and gut. To analyze the mechanism of intestinal infiltration of ATL cells, we made mAbs against ATL-43T, a human T cell line derived from an ATL patient with severe intestinal mucosal infiltration. One of the mAbs, named H920, was noted for a high and relatively specific reactivity with ATL-43T. Molecular cloning was done to identify this molecule and disclosed that the Ag molecule was identical to integrin beta 7. Since integrin beta 7 and its ligand MAdCAM-1 had been reported to mediate homing of lymphocytes to endothelial cells in intestinal mucosa, we next examined wither ATL-43T cells could adhere to MAdCAM-1+ cells. Human MAdCAM-1 transfectants of MMCE, a mouse epithelial cell line, were made and used to evaluate cell adhesion mediated by integrin beta 7 and MAdCAM-1. Considerable levels of cell adhesion were observed between ATL-43T and the transfectant cells, which was inhibited by H920 mAb in a dose-dependent manner. Furthermore, peripheral blood leukemic cells or lymphoma cells from 10 ATL patients were examined for expression of integrin beta 7 with regard to organ involvement. Samples from three patients with gastrointestinal tract involvement showed considerably higher expression of integrin beta 7. These results suggest that integrin beta 7 may play a role in adhesion and subsequent infiltration of a certain type of ATL cells into intestinal mucosa.

Adult↗

PubMed1999

WASP is involved in proliferation and differentiation of human haemopoietic progenitors in vitro.

The Wiskott-Aldrich syndrome (WAS) is an X-linked recessive disorder characterized by thrombocytopenia, immunodeficiency and eczema. X-linked thrombocytopenia (XLT) is a mild form of WAS with isolated thrombocytopenia. Both phenotypes are caused by mutation of the Wiskott-Aldrich syndrome protein (WASP) gene. In this study we investigated the role of WASP in the differentiation of CD34-positive (CD34+) cells isolated from the bone marrow of patients with WAS (n = 5) or with XLT (n = 4). Megakaryocyte colony formation was significantly decreased in patients with WAS when compared with normal controls. The formation of granulocyte-macrophage colonies and erythroid bursts were also decreased in WAS patinets. In contrast, in XLT patients, formation of all these colonies was normal. However, in vitro proplatelet formation of megakaryocytes induced by thrombopoietin was markedly decreased in both XLT and WAS. Electron microscopic examination revealed that megakaryocytes obtained from WAS or XLT patients grown in vitro had abnormal morphologic features, which seemed to be caused by defective actin cytoskeletal organization, including labyrinth-like structures of the demarcation membrane system and deviated distribution of the alpha-granules and demarcation membrane system. These observations indicate that WASP is involved in the proliferation and differentiation of CD34+ haemopoietic progenitor cells probably by its participation in signal transduction and in the regulation of the cytoskeleton.

Blood Platelets↗