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Biomedical subjects

K Iijima

Publications and source records attributed to K Iijima.

At least 145 records · Page 8Linked to original sources
PubMed1997

High shear stress attenuates agonist-induced, glycoprotein IIb/IIIa-mediated platelet aggregation when von Willebrand factor binding to glycoprotein Ib/IX is blocked.

High shear stress facilitates von Willebrand factor (vWF) binding to platelet glycoprotein (GP) Ib/IX, causing activation of GPIIb/IIIa to induce platelet aggregation. Here we report that activated GPIIb/IIIa, even occupied by ligands, is not sufficient to mediate platelet aggregation under high shear stress conditions when vWF binding to GPIb/IX is blocked. Platelet rich plasma or washed platelet suspension supplemented with purified human fibrinogen at a concentration of 2 mg/mL were treated with an anti-vWF monoclonal antibody NMC-4 which blocks the binding of vWF to GPIb/IX. After addition of 10 mumol/L ADP, aggregation was continuously monitored under various shear stress conditions (0-108 dyne/cm2) using a cone-plate type aggregometer previously described (Ikeda Y et al J Clin Invest 1991; 87:1234). The extent of maximal aggregation of agonist-stimulated platelets in the presence of NMC-4 correlated inversely with the level of shear stress applied, with the virtual absence of aggregation at 108 dyne/cm2. Once aggregated by 10 mumol/L ADP under low shear stress (12 dyne/cm2), platelets could be disaggregated, in part, by the application of high shear stress (108 dyne/cm2), and reaggregated when shear stress was returned to 12 dyne/cm2. Flow cytometric analysis revealed that platelets stimulated with 10 mumol/L ADP at 108 dyne/cm2 bound fluorescein isothiocyanate (FITC)-labeled fibrinogen, although aggregation was absent in this experimental condition. These results demonstrate the dual effect of shear stress on platelet functions; a pro-aggregating activity that induces vWF-GPIb/IX interaction leading to platelet activation, and an anti-aggregating force to prevent the growth of platelet thrombi. It is suggested that the efficacy of vWF blockade is greater under high shear than low shear stress conditions, and that a selective inhibition of platelet functions can be possible.

Adenosine Diphosphate↗
PubMed1997

Fumonisins as a possible contributory risk factor for primary liver cancer: a 3-year study of corn harvested in Haimen, China, by HPLC and ELISA.

Employing HPLC fluorometry, gas-liquid chromatography (GLC) and a novel enzyme-linked immunosorbent assay (ELISA) based on a monoclonal antibody, 40 corn samples, each collected in 1993 from agricultural stocks for human consumption in Haimen (Jiangsu County) and Penlai (Shandong Province), high- and low-risk areas for primary liver cancer (PLC) in China, respectively, were analysed for fumonisins (FBs), aflatoxins (AFs) and trichothecenes. Levels and positive rates of FBs and deoxynivalenol (DON) were significantly higher in Haimen than in Penlai. ELISA of the 40 corn samples harvested in the two areas in 1994 revealed that FB contamination levels and rates in these areas were comparable to those observed in 1993 in Haimen. ELISA analysis of 1993 and 1994 products revealed a wide occurrence of AFB1 but the positive rates as well as levels were not significantly different between these areas. ELISA of the same sample number of corn harvested in 1995 revealed that FB contamination in Haimen was significantly higher than in Penlai. These 3-yearly surveys of corn samples (240 in total) demonstrated that corn harvested in Haimen was highly contaminated with FBs and that the contamination level, as well as positive rate in 1993 and 1995, were 10-50-fold higher than those in Penlai, suggesting FBs as a risk factor for promotion of PLC in endemic areas, along with the trichothecene DON. Co-contamination with AFs, potent hepatocarcinogens, was assumed to play an important role in the initiation of hepatocarcinogenesis.

Aflatoxins↗
PubMed1997

Role of mesangial cells in macula densa to afferent arteriole information transfer.

1. Extraglomerular mesangial cells are strategically positioned between the macula densa and the afferent arteriole. These cells form a syncytium and are connected with glomerular mesangial cells via gap junctions. The model of immunoablation of mesangial cells in anti-Thy-1 glomerulonephritis carries the promise for understanding the function of mesangial cells as potential transmitters of information between the macula densa and the afferent arteriole. 2. The above anatomical relations between structures in the juxtaglomerular apparatus predict several possible routes of information flow. This review charts some hypothetical routes. 3. Research into the messenger systems involved in the transfer of signals from the macula densa to mesangial cells and from mesangial cells to the afferent arteriole suggests several candidate molecules to function in this capacity. Mechanisms of action for each candidate are discussed. 4. The oscillating nature of the afferent signal and efferent function in the tubuloglomerular feedback system, as well as other discoveries, offer a fertile field for future studies.

Animals↗
PubMed1997

[A clinicopathological study of 90 children with acute renal failure].

Clinical presentation, laboratory findings, renal biopsy findings and subsequent clinical course were studied retrospectively in 90 children with acute renal failure to intrinsic renal damage. The mean age at presentation was 8.1 years. Diagnosis and number of patients were as follows: Hemolytic uremic syndrome (HUS) in 32 patients, tubulo-interstitial nephritis in 19, idiopathic nephrotic syndrome in 10, IgA nephropathy on 9, membranoproliferative glomerulonephritis in 8, lupus in 5, poststreptococcal glomerulonephritis in 4, cortical necrosis in 1, Henoch Schoenlein purpura nephritis in 1 and anti-neutrophil cytoplasmic antibody associated glomerulonephritis in 1. Thirty-nine patients needed dialysis, but 36 of these were able to stop dialysis, 3 patients with HUS without gastrointestinal symptoms needed chronic dialysis. The mean follow-up period was 7.3 years from onset, and the the latest follow-up 82 patients had normal renal function, 3 showed chronic renal failure, 2 had regular dialysis, 2 had successful renal transplantation, an 1 had died due to heart failure. A poor outcome was associated with diffuse crescents and the presence of severe vascular changes. The early biopsy findings were very useful for the management of children with acute renal failure.

Acute Kidney Injury↗
PubMed1997

[Cord blood stem cell transplantation for infantile acute lymphoblastic leukemia after primary cytomegalovirus infection].

We report a 1-year-old boy with infantile lymphoblastic leukemia in first complete remission who received a cord blood stem cell transplantation (CBSCT) from an HLA identical sibling. We collected 120 ml of cord blood when his brother was born, which contained 4.2 x 10(8) mononuclear cells (4.2 x 10(7)/kg) and 3.1 x 10(5) CFU-GM (3.1 x 10(4)/kg). One month prior to transplantation, he showed persistent fever and liver dysfunction, and was finally diagnosed as having primary cytomegalovirus (CMV) infection which was demonstrated by elevation of serum anti-CMV-IgM. The administration of ganciclovir dramatically improved the clinical symptoms and abnormal laboratory findings, and was continued up to 1 month after transplantation to suppress the CMV reactivation. The preconditioning regimen consisted of busulfan (16 mg/kg/4 days) and cyclophosphamide (120 mg/kg/2 days), and cyclosporin A (CyA) alone was used for graft-versus-host disease (GVHD) prophylaxis. Fever suspicious of grade I GVHD developed on day 19, but subsided by increasing the dose of CyA. The WBC and platelet counts reached greater than 1,000/microliter and 50 x 10(3)/microliter on days 12 and 42, respectively. It is now at 13 months since transplantation, and he remains in a disease free state.

Antiviral Agents↗
PubMed1997

[Nutritional support in terminal patients--evaluation of 109 cases receiving home parenteral nutrition].

For end-stage patients with malignant disease, home parenteral nutrition (HPN) is an effective and useful treatment in terms of pain control and nutritional support. Therefore, these patients are able to spend their final days at home with their family. In 1990, we started the treatment and have been experienced 109 cases. In this report, we evaluate these cases and which condition or circumstance are necessary to perform HPN for the terminal patients.

Adult↗
PubMed1997

[Verapamil pretreatment extended the viability of non-beating donor hearts in situ].

An animal study was designed to examine whether the viability of asphyxiated cadaver hearts in situ could be extended by the verapamil pretreatment. Verapamil was administered separately at a dose of 0.1 (n = 9), 1.0 (n = 9), or 10 mg/kg (n = 16) to male adult Sprague-Dawley rats (440-500 g) 15 minutes prior to asphyxiation to death. Verapamil was not administered in control rats (n = 9). All dead rats were left at room temperature for 30 minutes followed by excision of their hearts and washout of coronary vascular beds with a cold University of Wisconsin solution. After simple cold storage for 30 minutes, hearts were reperfused on an isolated working rat heart apparatus in a nonworking mode with modified Krebs-Henseleit buffer for 60 minutes. After 30 minutes of the subsequent working mode, hemodynamics were measured and the hearts were perfused with 3% glutaraldehyde for the ultrastructural examination using electron microscopy. The hearts of the 10 mg/kg group were irreversibly contracted (0/16 vs. 8/9 in control hearts, p < 0.0001) during reperfusion, and most of them could make a pressure enough to keep a working mode (14/16 vs. 1/9 in control hearts, p = 0.0003). Satisfactory results were not found with 0.1 and 1.0 mg/kg verapamil groups. In ultrastructural examination, coronary vessels after preservation were dilated in the 10 mg/kg group, whereas were not dilated enough to washout of the red blood cells by the solution in controls. Irreversible changes of myocytes after reperfusion such as contraction bands and amorphous densities were presented in controls, but not in the 10 mg/kg group. Verapamil pretreatment before cardiac arrest may contribute to preserve cadaver hearts with dilating the coronary vessels and probably preventing the calcium influx into cardiomyocytes during ischemia and reperfusion. Verapamil provides dose-dependent extension of viability of non-beating donor hearts in situ.

Animals↗
PubMed1996

Activation-induced expression of vascular permeability factor by human peripheral T cells: a non-radioisotopic semiquantitative reverse transcription-polymerase chain reaction assay.

Vascular permeability factor, also known as vascular endothelial growth factor (VPF/VEGF), is a disulfide-linked dimeric glycoprotein of about 40 kDa that enhances vascular permeability, induces chemotaxis and activation of monocytes/macrophages, and promotes growth of vascular endothelial cells. It has been reported that several tumor cell lines and normal cells produce VPF/VEGF. To examine the possibility of VPF/VEGF mRNA expression in human peripheral T cells and its mechanism(s) of regulation, we developed a non-radioisotopic semiquantitative reverse transcription-polymerase chain reaction (RT-PCR; VPF/VEGF, GAPDH co-amplification) assay which detects all species of VPF/VEGF mRNA alternative splicing products. T cells expressed negligible VPF/VEGF mRNA in the resting state. However, TPA markedly enhanced the expression of 121-, 165- and 189-amino-acid-containing isoforms of VPF/VEGF mRNA in T cells. Both CD4+ and CD8+ T cells expressed VPF/VEGF mRNA in response to TPA treatment. Moreover, T cell receptor stimulation with monoclonal anti-CD3 antibody with or without IL-1 beta enhanced VPF/VEGF mRNA expression in T cells. These findings suggest that T cell activation induces VPF/VEGF expression in the cells, resulting in induction of its biological activities.

Endothelial Growth Factors↗
PubMed1996

A Case Reprot of Lactating Adenoma of the Breast and Review of the literatures in Japan.

We experienced a rare case of lactating adenoma in the mammary gland of a pregnant woman. A 21-year-old pregnant woman visited our clinic with a chief complaint of left mammary gland tumor. Based on palpation, mammograms and echograms, fibroadenoma or phyllodes tumor was diagnosed and enucleation was performed at the time of biopsy. The histopathological diagnosis was lactating adenoma.

Journal Article↗
PubMed1996

Sister chromatid exchanges in the peripheral lymphocytes of newborns with Down syndrome after in vitro exposure to blue or green light.

This study determines whether irradiation by blue or green light has an adverse effect on the DNA of Down syndrome (DS) cells by examining the sister chromatid exchange (SCE) frequency of peripheral lymphocytes obtained from five neonates with DS and five karyotypically normal neonates (control). Lymphocytes in G0 of the cell cycle were irradiated with blue or green fluorescent light for 1, 2, 4 or 6 h, and then cultured using a conventional method. Our results revealed that the induction of SCEs per cell in both groups increased in a dose-dependent manner, although more SCEs were respectively induced by the blue light. In addition, after 6 h of blue light irradiation, the net-induced SCEs in the DS groups were higher than those in the control groups.

Cells, Cultured↗
PubMed1996

Primary malignant melanoma of the rectum.

We present a case of primary malignant melanoma arising in the rectum of a 71-year-old woman who had presented with intermittent rectal bleeding following bowel movement 2 months previously. Digital and sigmoidoscopic examination of the rectum revealed a 3 x 2 x 1 cm exophytic tumor with a granular surface in the rectum 35 mm from the dentate line. No increased pigmentation was detected. Biopsy revealed degenerated mucosa accompanied by severe infiltration of inflammatory cells, but no malignant cells. The tumor and normal mucosa surrounding the tumor was excised 12 days after the biopsy. Light microscopy revealed the tumor to consist of malignant melanocytes and showed that the tumor was surrounded by normal mucosa. Immunohistochemical staining with antimelanoma antibody and HMB-45 substuntiated the diagnosis. Clinical and laboratory examination excluded the presence of melanoma at sites other than rectum. The patient refused an abdomino-perineal resection of the rectum and combination chemotherapy was performed. She died 18 months after the initial operation due to local recurrences and metastases to pelvic lymph nodes, liver, and lung.

Aged↗
PubMed1996

Distribution of diaphragm blood flow during sevoflurane anaesthesia in dogs.

PURPOSE: The purpose of this study was to determine the effect of increasing the concentrations of sevoflurane anaesthesia on the distribution of diaphragm blood flow (Qdi) in ten dogs during mechanical ventilation. METHODS: Animals were divided into two groups, sevoflurane (n = 6) and time control (n = 4) groups. Blood flow to the crural and the costal diaphragm (Qcru, Qcost) was determined by the hydrogen clearance technique at 0, 0.5, 1.0 and 1.5 minimum alveolar concentration (MAC) of sevoflurane after a 30 min period of steady-state conditions. Cardiac output (CO) and the mean arterial blood pressure (MBP) were also measured. RESULTS: Sevoflurane anaesthesia caused a reduction in CO (L.min-1) from a control value of 1.51 +/- 0.21 to 1.38 +/- 0.1 (0.5 MAC), 1.09 +/- 0.15 (1.0 MAC) and 0.98 +/- 0.12 (1.5 MAC) (Mean +/- SD). Mean blood pressure, Qcru and Qcost also decreased with increasing depth of anaesthesia. In addition, the decrease of Qcru was greater than that of Qcost at all levels of MBP and CO. No change occurred in these variables in the time control group. CONCLUSION: Sevoflurane anaesthesia changes the distribution of Qdi with a greater reduction occurring in Qcru than in Qcost.

Anesthetics, Inhalation↗
PubMed1996

Molecular remission achieved by interferon therapy in a patient with cytogenetically relapsed chronic myelogenous leukemia after syngeneic bone marrow transplantation.

A patient with chronic myelogenous leukemia (CML) in chronic phase (CP) had been treated with a syngeneic bone marrow transplantation (BMT). Cytogenetic remission was confirmed 3 months later. One year after transplantation, hematological remission persisted while cytogenetic analysis revealed a recurrence of Philadelphia chromosome (Ph1). Five months later, we began treatment with human lymphoblastoid interferon (HLBI), a natural interferon (IFN)-alpha. Fourteen months after initiation of HLBI administration, cytogenetic analysis of the patient's bone marrow showed disappearance of Ph1 positive cells. One year after confirming cytogenetic remission, the absence of bcr-abl transcripts by polymerase chain reaction (PCR) assay indicated molecular remission. IFN therapy appears to be the first choice of treatment for cytogenetic relapse after syngeneic BMT. The efficacy of IFN appears to be due to an anti-malignancy effect, not to graft versus leukemia (GVL) effect.

Adult↗
PubMed1996

Effects of lycopene, a carotenoid, on intrathymic T cell differentiation and peripheral CD4/CD8 ratio in a high mammary tumor strain of SHN retired mice.

We previously reported that lycopene, one of the carotenoids, significantly suppressed the development of spontaneous mammary tumors of mice and the contribution of lycopene to the maintenance of physical homeostasis was suggested. In this study, we investigated the effects of lycopene on the intrathymic and peripheral T cell subpopulation as immunoregulatory parameters. In tumorous control mice, inactivation of intrathymic T cell differentiation, an increase of the percentage of CD4+ CD8+ cells and a decrease of CD4+CD8+ cells were observed. On the other hand, in the lycopene-treated mice, the abnormal intrathymic T cell differentiation was recovered and brought to non-tumorous levels. The peripheral CD4/CD8 ratio was partially augmented by lycopene treatment which resulted from an increased CD4+ subpopulation. These observations suggest that one of the immunomodulating roles of lycopene is to normalize the change of intrathymic T cell differentiation caused by tumorigenesis.

Animals↗
PubMed1996

Expression of type IV collagen alpha 3 and alpha 4 chain mRNA in X-linked Alport syndrome.

X-Linked Alport syndrome is caused by mutations in the COL4A5 gene encoding the Type IV collagen alpha 5 chain (alpha 5(IV)). The authors' recent immunohistochemical study demonstrated abnormal expression of alpha 3(IV) and alpha 4(IV), as well as of alpha 5(IV), in patients with this syndrome, and a correlation between abnormal alpha 3(IV) and alpha 4(IV) expression and severity of the disease. The mechanism linking alpha 5(IV) mutations with abnormal alpha 3(IV) and alpha 4(IV) expression is unknown. To examine alpha 3(IV) and alpha 4(IV) mRNA expression in renal cortical tissues of patients with X-linked Alport syndrome, a nonradioisotopic, semiquantitative reverse transcription-polymerase chain reaction assay (alpha 3(IV) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), alpha 4(IV), and GAPDH coamplification) was performed. There were no significant differences among severely affected male (N = 3), mildly affected male (N = 2), and female (N = 1) X-linked Alport patients and control subjects (N = 2) with respect to alpha 3(IV) and alpha 4(IV) mRNA expression in renal cortical tissue. These findings indicate that alpha 3(IV) and alpha 4(IV) transcription is not turned off in X-linked Alport syndrome and suggest that abnormal expression of alpha 3(IV) and alpha 4(IV) proteins in this syndrome may be the result of failure of incorporation of alpha 3(IV) and alpha 4(IV) into the glomerular basement membrane.

Adult↗
PubMed1996

[Influence of social environments on brain aging].

To investigate influence of social activity on normal brain aging, we studied the social activity score, cognitive functions, self-rating depression scale, cerebral blood flow (CBF), MRI and motor function in the normal elderly people living in different social environments. There was no difference in risk factors for stroke, MRI findings and CBF between the two groups. However, the subjects living in a home for elderly showed significantly lower social activities than those living with families. Cognitive functions and motor function were lower, and SDS was higher in subjects living in retirement house than those living with families. The social environment including social activities closely related to life style may significantly influence brain aging with regard to silent brain infarctions or risk factors for stroke.

Aged↗