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Biomedical subjects

M Yamaguchi

Publications and source records attributed to M Yamaguchi.

At least 541 records · Page 30Linked to original sources
PubMed1998

Platelet-like particle production from cultured human megakaryocytic cell line.

The human megakaryocytic cell line CMK was positive for the expression of platelet glycoprotein(GP) IIb/IIIa but few cells were positive for GPIb. To establish a GPIb-positive CMK subclone, GPIb-positive CMK cells were purified, micromanipulated and cloned, but resulting sublines were all negative for GPIb expression. The combined presence of interleukin-3 (IL-3) and the anti-virus agent ribavirin strongly induced expression of GPIb on the cells. However, the megakaryocyte growth and development factor (MGDF)/thrombopoietin (TPO) failed to enhance GPIb expression. CMK themselves and particles are negative for GPIb expression. To utilize these particles as platelet substitutes, further appropriate culture systems are necessary.

Blood Platelets↗
PubMed1998

Inflammatory cytokine production in whole blood modified by liposome-encapsulated hemoglobin.

The effect of Neo Red Cells (NRC), liposome-encapsulated hemoglobin, on production of tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6) were studied in whole blood preparations ex vivo. Venous blood was collected with heparin and incubated in a CO2 incubator. Treatment of blood samples with NRC reduced the constitutive levels of TNF-alpha and IL-6. Lipopolysaccharide (LPS) treatment for 24 h increased production of TNF-alpha and IL-6 in a dose-dependent manner. Pretreatment with NRC (5%) for 24 h markedly potentiated the LPS-induced TNF-alpha production and, that of IL-6 to a lesser extent. Northern blotting analysis of total RNA in whole blood showed that pretreatment with NRC caused a marked increase in TNF-alpha mRNA expression in response to LPS. It is concluded that NRC potentiates LPS-induced TNF-alpha and IL-6 production in whole blood ex vivo, and that the potentiating effect of NRC on LPS-induced TNF-alpha production can be attributed, at least in part, to an increase in its mRNA expression.

Adult↗
PubMed1998

[A case of fibrous histiocytoma of the appendix with twisted stalk].

A 74-year-old man consulted this hospital with the chief complaint of lower right abdominal pain on February 13, 1998. He was hospitalized, subjected to abdominalechography and CT, and diagnosed as having subileus caused by an intraperitoneal tumor. Surgery was performed on February 25, 1998. When the abdomen was incised, a chicken egg-sized tumor at the end of theappendix were found. In addition, the stalk of the appendix was twisted. Appendectomy was therefore performed. Upon histopathological examination, it was found that the submucosal tumor originated at the end of the appendix, and proliferation of spindle-shaped fibroblast-like cells and histocytic oval cells was observed in the tumor. Since various histiocyte markers were positive upon immunohistological examination, the tumor was considered to be of histiocytic origin. However, the tumordid not exhibit polymorphism, heteromorphism, or mitotic figures which would confirm a diagnosis of malignant fibrous histiocytoma. It was thus diagnosed as a fibrous histiocytic tumor on the borderline between malignant and benign. We report the present case because the occurrence of a primary fibrous histiocytoma in an appendix of which the stalk is twisted is very rare.

Aged↗
PubMed1998

[A patient with EDTA-dependent pseudothrombocytopenia who underwent emergent clipping surgery for a ruptured aneurysm].

A 42-year-old female with EDTA-dependent pseudothrombocytopenia underwent emergent clipping surgery for a ruptured aneurysm. On admission, the platelet count was low, but bleeding time and coagulation test were within normal limits. The blood smear anticoagulated with EDTA revealed remarkable agglutination of platelets, while heparinized blood showed a normal level. Diagnosis of EDTA-dependent pseudothrombocytopenia was made. The progressive drop in platelet count occurred within 10 minutes in the presence of EDTA. The autocounter misjudged the agglutination of platelets as red or white blood cells. The earlier study reported the incidence of this diseases as 0.07%. This disease is often misdiagnosed. Therefore, thrombocytopenia without any clinical symptom should be considered as showing a possible symptom of EDTA-dependent pseudothrombocytopenia.

Adult↗
PubMed1998

High density culture of immortalized liver endothelial cells in the radial-flow bioreactor in the development of an artificial liver.

Liver endothelial cells are important components of the tissue along the hepatic sinusoid. They are responsible for microcirculation in the liver and scavenger functions. It would therefore be important to include these cells in any hybrid type of artificial liver in addition to hepatocytes. However, it is difficult to culture these cells in vitro. The development of a liver endothelial cell line, which maintains the characteristics of the primary culture, would thus be of great benefit in the development of an artificial liver. In the present study we established immortalized liver endothelial cells from the liver of an H-2Kb-tsA58 transgenic mouse, which harbors the SV40 TAg gene. Hepatic sinusoidal cells isolated from H-2Kb-tsA58 mouse proliferated in the presence of gamma-interferon at 33 degrees C. Four clones were established, out of which clone M1 had the highest amounts of PGI2 production, as well as plasminogen activator activity and internalized acetylated low density lipoprotein. On culture dishes the M1 cells grew individually and spread. Sieve plates on the cell surface were not readily visible, but small pores were detected under electron microscopic observation. These results suggest that M1 clone cells originated from liver endothelial cells. Moreover it was possible to culture the immortalized liver endothelial cells in a radial-flow bioreactor for 5 days, with a maximum 6-keto prostaglandin F1alpha production of 25 microg per day. This suggests that immortalized liver endothelial cells and a radial-flow bioreactor can prove useful tools in the development an artificial liver.

Animals↗
PubMed1998

[Medial collateral ligament of the knee and its surroundings: MRI findings of normal and abnormal structures].

Normal and abnormal structures of the medial corner of the knee were evaluated with coronal and axial MR images. MRI revealed 35 medial collateral ligament (MCL) tears and 61 medial meniscus (MM) tears in 200 consecutive examinations. Just under the MCL, little or no fluid retention was identified between the superficial and deep layers of the MCL or between the MM and MCL in normal knees and in cases of MM tears. At the anterior aspect of the MCL, the deep layer merges with the capsule of the suprapatellar bursa, potentially leaving space for fluid retention. Fluid collection posterior to the MCL was demonstrated in a few cases. Fluid retention with edematous swelling just under the MCL was noted in the cases of MCL tears. MM-MCL distances in the cases of normal structure, MM tears and MCL tears were 2.1 mm, 2.7 mm and 4.7 mm, respectively. The deep layer of the MCL, which was enhanced by the presence of joint fluid, was identified in 71% of cases.

Adult↗
PubMed1998

Quantitative analysis of nonuniform distributions in lung perfusion scintigraphy.

UNLABELLED: Nonuniform distributions of lung perfusion scintiscans obtained by SPECT were quantified to supplement qualitative lung scintiscans. A total of 126 lung perfusion scintigraphy examinations were performed between February and December 1996 on a subject population of 102 patients, including 8 control subjects. All of the subjects were broadly classified according to whether they had pulmonary disease or nonpulmonary disease. The latter group was subdivided into a group with cardiac disease and other diseases. The grade of breathlessness was classified according to whether oxygen inhalation was required, the clinical severity of the breathlessness and patient's performance status. Blood gas analysis was performed in 21 cases, and pulmonary function testing was performed in 26 cases. METHODS: With the subjects resting in the supine position, 185 MBq 99mTc-macroaggregate albumin was infused. From reconstructed SPECT images, the volume of lung as a whole calculated at 10% of threshold was assumed to be the functional lung volume, and the functional volume rates were calculated in 10% threshold widths from 10% to 100% of thresholds. Assuming the total absolute difference in functional volume rate between each subject and the control to be the distribution index of the lung as a whole (D index), we quantified the degree of nonuniform distribution in each subject. RESULTS: The D index of all subjects ranged from 2.7 to 72.2. The mean D index in pulmonary disease was significantly higher than in nonpulmonary disease (p < 0.0005) and cardiac disease (p < 0.005). It was significantly positively correlated with the grade of breathlessness, significantly negatively correlated with the oxygenation index and significantly positively correlated with measured vital capacity and forced expiratory volume in 1 sec as percentages of their predicted values. CONCLUSION: The D index is a useful indicator for quantifying nonuniform distributions on lung scintiscans. If it is used as a supplement to qualitative interpretation of scintiscans, pulmonary perfusion scintigraphy will become a more useful technique for clinical evaluation of treatment and assessment of breathlessness and respiratory failure than the usual one.

Aged↗
PubMed1998

[Effect of combination chemotherapy of low-dose CDDP. Continuous infusion of 5-FU, and intermittent CPT-11 administration for 2 advanced pancreatic cancer cases with liver metastasis].

For advanced pancreatic cancer, there is no typical chemotherapy regimen non single chemotherapeutic agent. For example, 5-FU, Doxorubicin, MMC and Epirubicin obtained only 15-24% efficacy, and general combination chemotherapy was FAM, 5-FU+CDDP and 5-FU+Leucovorin for pancreatic cancer. Generally, in pancreatic cancer cases the performance status was poor, and most could not endure the chemotherapy regimen. 5-FU continuous infusion and low-dose CDDP regimen were effective and showed fewer side effects for pancreatic cancer. Then, for 2 cases of advanced pancreatic cancer with liver metastasis, 5-FU continuous infusion + low-dose CDDP + intermittent CPT-11 administration (5-FU 500 mg/body/24 hr + CDDP 5mg x 5 days-6 courses + CPT-11 100 mg-125 mg-150 mg, bolus i.v. intermittently) was effective. Thus, this regimen could well be effective for advanced pancreatic carcinoma.

Adenocarcinoma↗
PubMed1998

Role of calcium-binding protein regucalcin in regenerating rat liver.

Regucalcin is a novel calcium-binding protein which does not contain EF-hand motif as a Ca2+-binding domain. The organization of the rat regucalcin gene consists of seven exons and six introns. Its mRNA is mainly present in liver but slightly in kidney with a size of 1.8 kb. Hepatic regucalcin mRNA expression is stimulated by various factors including calcium, calcitonin, insulin, and oestrogen in rats. The mRNA is also expressed in hepatoma cells (Morris hepatoma and HepG2). Regucalcin plays a role in the maintenance of cytosolic Ca2+ homeostasis in liver cells. Moreover, regucalcin has an inhibitory effect on Ca2+/calmodulin-dependent enzyme activation, protein kinase C activation, and many Ca2+-activated enzymes, indicating a role in the regulation of the Ca2+-signalling system. Recently, regucalcin has been demonstrated to regulate nuclear function in liver cells. Regucalcin can inhibit Ca2+-activated nuclear DNA fragmentation in rat isolated liver nuclei. Furthermore, the liver nuclear DNA and RNA syntheses are inhibited by regucalcin. Such an effect of regucalcin is also seen in the nuclei of regenerating rat liver. The regucalcin mRNA level is increased in regenerating liver. These findings suggest that regucalcin plays a regulatory role in the suppression for overexpression of proliferative cells.

Animals↗
PubMed1998

In vitro expansion of CD34+/CD41+ cells from human peripheral blood CD34+/CD41- cells: role of cytokines for in vitro proliferation and differentiation of megakaryocytic progenitors.

The aim of this study is to clarify the transitional change of the proliferation and differentiation of human peripheral blood CD34+ cells to megakaryocytic lineage, focusing on its clinical application. We developed a rapid system to purify human peripheral blood CD34+ cells from healthy volunteers, which produced CD34+ cells with a 90% purity. The purified CD34+ cells predominantly consisted of CD41- cells, and the rate of coexpression of CD41 was 0.6% +/- 0.5%. When the purified cells were cultured in liquid phase for 10 days in the presence of recombinant human stem cell factor (rSCF: a ligand for c-kit), interleukin-3 (rIL-3), and thrombopoietin (rTPO: a ligand for Mpl), the number of CD34+/CD41+ cells increased to 19% +/- 7% of total expanded cells on day 4 (4 days of liquid culture) and then gradually decreased to 2.2% +/- 0.6% on day 10. The absolute number of CD34+/CD41+ cells increased and reached a plateau on day 6, and 1.7 +/- 0.6 x 10(5) CD34+/CD41+ cells were produced by 1 x 10(5) CD34+/CD41- day 0 cells. The CD34-/CD41+ cells appeared on day 6, continuously increased in number until day 10, and constituted the main population of expanded cells on day 10, with a value of 38% +/- 18%. On day 10, 19.5 +/- 10.6 x 10(5) of CD34-/CD41+ cells were produced by 1 x 10(5) CD34+/CD41- day 0 cells. The deletion of rTPO from this cytokine combination decreased the number of CD34+/CD41+ and CD34-/CD41+ cells, after days 6 and 8, respectively. Day 0 cells required rIL-3 for promoting colonies containing megakaryocytes, whereas rTPO alone promoted almost no megakaryocytic colonies from day 0 cells. Thus, a combination of IL-3 and SCF expands CD34+/CD41+ cells from CD34+/CD41- cells, and TPO mainly acts to increase CD34-/CD41+ cells. This study suggests that if the expansion of CD34+/CD41+ is performed in vitro, the 6 days' culture of peripheral blood CD34+/CD41- cells with a combination of IL-3 and SCF with TPO provides the most rapid and stable products of CD34+/CD41+ cells for the rapid recovery of platelets in patients with peripheral blood stem cell transplantation.

Adult↗
PubMed1998

Continuous and simultaneous cultivation of benthic food diatom Nitzschia sp. and abalone Haliotis sieboldii by using deep seawater.

By using low-temperature, clean, and nutrient-rich properties of deep seawater (DSW; seawater below the euphotic layer), a continuous and simultaneous cultivation system for a benthic food diatom, Nitzschia sp., and juvenile abalone was established. Cell suspension of Nitzschia sp. was added to a bioreactor made of acrylic pipe (7 cm diameter x 50 cm long) containing short vinyl tubes (2 cm diameter x 2 cm long) as substrata. DSW collected from 320 m depth at Muroto City, in Kochi Prefecture, Japan, was supplied to the reactor and incubated under natural light (ca. 6000 lux) with a continuous DSW flow rate of 40 turnovers per hour. After growing enough benthic diatoms in the reactor, juveniles of abalone, Haliotis sieboldii (shell length ca. 10-20 mm) were put into a reactor, and cultivated simultaneously with food diatoms in the continuous flow system. During the four-month incubation, 7-month-old abalone juveniles with a shell length of 12.4 (average) +/-0.2 (SD) mm were grown to 19.4 (+/-1.7) mm in the reactor. Daily growth rates of abalones were 50-110 µm/day. These results indicate that the continuous cultivation system with DSW supports the growth of juvenile abalone without any supply of seaweed until it grows to release size.

Journal Article↗
PubMed1998

[Disturbance of deep sensation in medial medullary syndrome. Topographical localization of medial lemniscus in the medulla oblongata].

Medial medullary infarction is characterized by ipsilateral hypoglossal nerve palsy with contralateral hemiparesis and disturbance of deep and discriminative sensory perception. We examined the extent and distribution of disturbances in deep sensation and compared the findings with the lesion location in the medial lemniscus detected by MRI in 3 patients with medial medullary infarction. We classified the lesion location into 2 groups; type I and type II. Type I was ventral to the middle medial lesion of the medial lemniscus, and type II was ventral to the dorsal medial lesion. In our series, type I (Case 1) impairment of the three kinds of deep sensations was more severe in the lower extremities than in the up-per extremities. In type II (Cases 2, 3) the severity or impairment in the upper extremities was moderate or severe and nearly equal to that in the lower extremities. There was no difference in the severity of impairment for the four kinds of discriminative sensations. In the literature, type I (8 patients) impairment of position sense in deep sensation was found in 1 of 7 patients in the upper extremities and 5 of 7 patients in the lower extremities. Impairment of vibration sense was found in 1 of 7 patients in the upper extremities and in all patients in the lower extremities. In type II (14 patients) severe impairment of position and vibration sense in deep sensation was found in 3 patients in the upper extremities equal to that in the lower extremities. There was no tendency in the severity of impairment of four kinds of discriminative sensations. Including our 3 cases and 22 in the literature, impairment of deep sensation was more severe in the lower extremities than in the upper extremities in type I (9 patients) and the extent was none (7), mild or moderate (2) in the upper extremities, mild (2), moderate (1), severe (2), obscure (4) in the lower extremities, while in type II (16 patients) the severity in the upper extremities was nearly equal to that in the lower extremities and the extent was none (1), mild or moderate (1), severe (5), obscure (9) in the upper extremities, none (2), mild or moderate (1), severe (6), obscure (7) in the lower extremities. It is concluded that hemiparesis appeared with lesions located in the pyramidal tract of the medulla, hemiparesis and disturbance of deep sensation in the upper and lower extremities, predominantly in the lower extremities with the lesion of the pyramidal tract to the middle of medial lemniscus in the medulla, hemiparesis and disturbance of the upper and lower extremities deep sensation with lesions of the pyramidal tract to the whole of the medial lemniscus in the medulla. Evaluating deep sensation of the upper and lower extremities is useful for speculation of the lesion location in the medial lemniscus in medial medullary infarction.

Cerebral Infarction↗
PubMed1997

The placenta is not the main source of leptin production in pregnant rat: gestational profile of leptin in plasma and adipose tissues.

The gestational profiles of leptin in plasma, adipose tissue and placenta were investigated in rats. Leptin in plasma and the adipose tissue of the maternal compartment increased as pregnancy advanced and remained high during the latter half of pregnancy (approximately 2-fold compared with the non-pregnant state), followed by a rapid decrease just before parturition. Leptin in fetal plasma and amniotic fluid was first detectable on day 19 and then increased to levels comparable to those in maternal plasma of non-pregnant and day 21 pregnant rats. The total amount of mRNA in maternal adipose tissues significantly increased as pregnancy advanced and reached about 2.5-fold of those of non-pregnant rats on day 19 of pregnancy, followed by a marked decrease on day 3 of lactation. Placentae and decidual tissues did not show any expression of leptin mRNA on day 12 and 19 of pregnancy. These results indicate that the placenta is not a major source of leptin production in rats and also suggest the physiological significance of leptin in rat pregnancy.

Adipose Tissue↗
PubMed1997

Increase of mouse leptin production by adipose tissue after midpregnancy: gestational profile of serum leptin concentration.

The serum concentration of leptin in 10 week old virgin ICR mice assessed by RIA was 1.70 +/- 0.08 ng/ml. The serum leptin concentration in the pregnant mice mated at 10 weeks of age significantly increased from day 11 of pregnancy and reached a peak on day 17 of pregnancy (42.2 +/- 4.8 ng/ml). AFter the delivery, the serum leptin concentration rapidly decreased and reached the level of the virgin mouse on the seventh day in the puerperium. Tissue contents of leptin in the placenta, the decidua, the uterus, and the adipose tissue were between 40 to 130 ng/g wet tissue. However, leptin mRNA was expressed only in the adipose tissue and the level of leptin mRNA on days 13 and 17 of pregnancy increased 3- to 5-fold compared with that of virgin mouse. Tissue content of leptin in the adipose tissue significantly increased from day 17 of pregnancy compared with that of the virgin mouse. The m-leptin secretion from the adipose tissue also significantly increased in vitro. These results suggest that leptin, which was secreted by adipose tissue, may play important roles in mouse reproduction after midpregnancy.

Adipose Tissue↗
PubMed1997

Distinct roles of E2F recognition sites as positive or negative elements in regulation of the DNA polymerase alpha 180 kDa catalytic subunit gene promoter during Drosophila development.

The transcription factor E2F plays a key role in transcriptional control during the growth cycle of higher eukaryotic cells. The promoter region of the DrosophilaDNA polymerase alpha 180 kDa catalytic subunit gene contains three E2F recognition sequences located at positions -353 to -342 (E2F site 1), -21 to -14 (E2F site 2) and -12 to -5 (E2F site 3) with respect to the transcription initiation site. Various base substitutions were generated in each or all of the three E2F sites in vitro to allow examination of their effects on E2F binding and promoter function in cultured Kc cells as well as in living flies. Glutathione S-transferase (GST)-E2F and GST-DP fusion proteins were found to cooperate in binding to the three E2F sites in the DNA polymerase alpha gene promoter in vitro. In contrast, an E2F-specific activity detected in nuclear extracts of Kc cells showed little affinity for E2F site 1 but strong binding to sites 2 and 3. Transient expression of Drosophila E2F in Kc cells activated the DNA polymerase alpha gene promoter and the target sites for activation coincided with E2F sites 2 and 3. However, analyses with transgenic flies indicate that E2F site 3 functions positively in terms of DNA polymerase alpha gene promoter activity, while E2F sites 1 and 2 rather have a negative control function. Thus E2F sites play distinct roles as positive or negative elements in regulation of the DNA polymerase alpha gene promoter during Drosophila development.

Animals↗