Biomedical subjects

S Hamano

Publications and source records attributed to S Hamano.

At least 55 records · Page 3Linked to original sources

PubMed1999

Cytocidal activity of PBL, LAK, and IDEC-C2B8 and expression of HLA class 1, ICAM-1, and CD20 in vincristine-resistant hematologic cell lines.

This study was designed to determine whether the cytocidal activity of immunotherapy such as cytotoxic peripheral blood lymphocytes (PBL), lymphokine-activated killer (LAK) cells, and chimeric anti-CD20 mouse/human monoclonal antibody, IDEC-C2B8, overcome vincristine (VCR) resistance in cultured cell lines derived from human leukemia/lymphoma. In addition, the relation between the susceptibility to these immunotherapies and the expression levels of HLA class 1 and ICAM-1 as well as CD20 on the cell surface was analyzed. Three of six VCR-resistant cell lines were less susceptible to PBL cytotoxicity compared with wild-type cells, whereas the susceptibility was kept in the other three VCR-resistant cell lines. Four of six VCR-resistant cell lines were less susceptible to LAK activity and the other two cell lines were as sensitive to LAK cells as their wild-type counterparts. There was no correlation between the susceptibility for PBL cytotoxicity and the expression of HLA class 1 in both wild and VCR-resistant cells. In contrast, ICAM-1 in the two cell lines that showed decreased susceptibility for LAK cytotoxicity disappeared, although that in one cell line increased. IDEC-C2B8 was effective only against B-cell lines expressing CD20. One cell line in which the expression of CD20 increased was nearly six times more sensitive to IDEC-C2B8 than wild type. Thus, we concluded that the resistance to VCR in some tumor cell lines is associated with modified susceptibility for immunotherapies by the different expression of target molecules from those of wild-type counterparts.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1999

Effect of ozagrel on locomotor and motor coordination after transient cerebral ischemia in experimental animal models.

The effect of ozagrel, a selective thromboxane A(2) (TXA(2)) synthetase inhibitor, on the obstruction after cerebral ischemia-reperfusion was studied in experimental animal models. The reduced spontaneously locomotor activity and the obstruction of motor coordination were improved by the administration of ozagrel in the conscious cerebral ischemia-reperfusion mouse model. Ozagrel suppressed the decrease in specific gravity of the brain tissue induced by the occlusion-reperfusion in the conscious cerebral ischemia-reperfusion SHR model, and recovered the postischemic decrease in cortical PO(2) after middle cerebral artery occlusion-reperfusion in cats. The level of TXB(2), a metabolite of TXA(2), in the brain increased after the cerebral ischemia-reperfusion, and ozagrel prevented this increase. Additionally, ozagrel also increased the level of 6-keto-PGF(1alpha), a metabolite of prostaglandin I(2) (PGI(2)), in the brain tissue after cerebral ischemia-reperfusion, and the administration of PGI(2) improved the reduced spontaneous locomotor activity in the conscious cerebral ischemia-reperfusion mouse model. Our data suggest that ozagrel suppressed the obstruction following cerebral ischemia-reperfusion by preserving the cerebral blood flow via preventing the increase in TXA(2) and causing an increase in the PGI(2) level.

6-Ketoprostaglandin F1 alpha↗

PubMed1999

Disulfide formation in bovine zona pellucida glycoproteins during fertilization: evidence for the involvement of cystine cross-linkages in hardening of the zona pellucida.

The time for solubilization of the bovine zona pellucida in a hypotonic buffer containing 5% (v/v) beta-mercaptoethanol and 7 mol urea l-1 increased by 10% after fertilization. Coupling with a specific fluorescent thiol probe, monobromobimane (mBBr), was markedly greater in the zona pellucida of ovarian eggs compared with fertilized eggs, indicating that the cysteine residues in the zona pellucida of unfertilized eggs are oxidized to cystines during fertilization. After endo-beta-galactosidase digestion to remove N-acetyllactosamine repeats of the carbohydrate chains, three zona pellucida glycoproteins (ZPA, ZPB and ZPC) coupled with the fluorescent bimane groups were fractionated efficiently by reverse-phase HPLC. Estimation of bimane groups in the three components and SDS-PAGE revealed that intramolecular disulfide bonds in ZPA and intra- and intermolecular disulfide bonds in ZPB were formed during fertilization, but oxidation of cysteine residues in ZPC was low. Specific proteolysis of ZPA during fertilization was also observed. These results indicate that the formation of disulfide linkages together with specific proteolysis result in the construction of a rigid zona pellucida structure, which is responsible for hardening of the zona pellucida.

Animals↗

PubMed1999

[Childhood multiple sclerosis and allied demyelinative diseases].

We report five cases of multiple sclerosis (MS) and three cases of allied demyelinative diseases starting during childhood. Three of the MS patients presented with atypical initial symptoms, such as acute encephalitis or myelitis, making an early clinical diagnosis difficult. Ophthalmologic symptoms were noted in four of MS children, and in two with allied demyelinative diseases. Therefore, if a child shows ophthalmologic symptoms (i.e. optic neuritis, ophthalmoplegia), brain magnetic resonance imaging (MRI) should be conducted for the differential diagnosis of MS and other demyelinative diseases. Cerebrospinal fluid analysis is not useful for the initial diagnosis of MS, because pleocytosis and increase of oligoclonal IgG band in cerebrospinal fluid are seen in both MS and other demyelinative disorders. However, neuron specific enolase (NSE) is slightly higher in the latter than in the former. T2-weighted MRI of multiple sclerosis showed multiple high intensity areas in the white matter of the cerebrum and cerebellum, capsula interna, and crus cerebri etc. Most of these lesions were clinically silent, being characteristic of MS. In two MS cases, however, initial MRI revealed no abnormal findings. Thus, the diagnosis of MS can not be made by initial MRI only.

Biomarkers↗

PubMed1999

[Lissencephaly type I: electroencephalographic findings and neuroradiological classification].

Lissencephaly type I is a diffuse type of migration disorder that contains agyria and/or pachygyria on the brain surface. We experienced 5 cases of this disease and evaluated their electroencephalographic findings and seizure types based on the neuroradiological classification of lissencephaly. Ages at seizure onset ranged from 2 months to 4 months (mean 3.2 months). The patients with complete agyria had generalized tonic seizures, and those with pachygyria partial seizures or tonic spasms. The characteristic findings of complete agyria in electroencephalogram were high-voltage alfa activity. The amount of high-voltage slow waves increased with the ratio of pachygyria on the brain surface. The appearance of multifocal spikes and sharp waves suggested irregular arrangement of pachygyria on the brain surface.

Brain↗

PubMed1999

[Topography and number of cortical tubers in tuberous sclerosis: comparison between patients with and without West syndrome].

To reveal the role of cortical tubers in the pathophysiology of West syndrome associated with tuberous sclerosis, we studied their numbers and topography, focusing on the differences between patients with infantile spasms and without infantile spasms. We reviewed the clinical date on the seizure types, seizure evolution and developmental status of 13 patients: 8 patients with infantile spasms (the West syndrome group) and 5 patients without infantile spasms (the non-West syndrome group). The number, size and location of the cortical tubers were evaluated on 5 mm-thick T2-weighted MR images. The average number of cortical tubers of the West syndrome group was 11.4 per patient, being larger than that of the non-West syndrome group (7.8). The West syndrome group included two patients with only one tuber. The average number of the cortical tubers in the occipital lobes of the West syndrome group was 2.4, which was larger than that of the non-West syndrome group (0.8). From these results, a large number of cortical tubers, which suggest involvement of larger cerebral cortical regions, increase the possibility of the West syndrome in patients with tuberous sclerosis. On the other hand, some patients with only one or few cortical tubers developed West syndrome, which may suggest the presence of a region critical on the development of West syndrome. Our results also suggest that lesions in the occipital lobes might be more significant than those in other lobes. However, the results of this study are diverse, to some extent, which may have resulted from variable epileptogenicity of the cortical tubers. It is necessary to conduct further study, including a greater number of patients, to reveal topographic pathophysiology in West syndrome.

Cerebral Cortex↗

PubMed1999

[Electroconductive lithotripsy: clinical results of the Sonolith sigma].

The electroconductive lithotripter (ECL) is a new concept for shockwave generation in which a highly conductive solution channels the discharge between the anode and cathode. Out of 152 patients treated, complete follow up data were available on 151 patients. The average number of shocks per treatment was 2,138. At 3 months the overall stone-free rate was 73.5%. Success rate, defined as stone-free or asymptomatic residual fragments measuring 4 mm or less, was 84.9% for renal and 94.9% for ureteral calculi. The overall success rate for all calculi was 89%.

Adult↗

PubMed1999

[Morphometric development and the variability of neurons of the human auditory system: ventral cochlear nucleus and superior medial olivary nucleus].

The development of the human ventral cochlear and medial superior olivary nuclei was studied. We made serial sections of the brain in 10 fetuses at 16-40 weeks of gestation (WG), an infant at 2 months of age and an adult of 63 years using an electronic planimeter with a computer. Although the shape of neurons of the two nuclei was different, our morphometric analysis showed that the development of both of them accelerates between 18 and 21 WG in terms of the columnar length and volume, neuronal size and circularity ratio and the amount of Nissl bodies increases gradually.

Cochlear Nucleus↗

PubMed1998

Detection of histo-blood group ABO mRNA in human chronic myeloid leukemia cell lines using reverse transcription-polymerase chain reaction (RT-PCR).

ABH carbohydrate antigens are cell surface carbohydrates which occur in three allelic forms, namely A, B and O blood groups. It is unknown how the ABO blood group is expressed in hemopoietic stem cells. In an attempt to verify the ABO mRNA expression in hemopoietic precursor cells, mRNAs were isolated from human chronic myeloid leukemia (CML) cell lines which are believed to be at the most immature level of hemopoietic differentiation among hemopoietic malignancies. In particular, K-562 and KOPM-28 cells were used with the reverse transcription-polymerase chain reaction (RT-PCR) technique for amplifying ABO gene transcripts. The amplified ABO cDNAs from two cell lines were characterized by the digestion of Kpn-I restriction enzyme. The blood types were determined by polymerase chain reaction of the specific allele (PASA) method. Both of the human chronic myeloid leukemia cell lines expressed ABO mRNA. The quantity of ABO mRNA in the K-562 cell line is significantly higher than that of the KOPM-28 cell line. The ABO blood type of these two cell lines was type O. Because the CML cell lines are presumed to be at the immature stem cell level of hematopoietic cell differentiation and because it is believed that the cultured cell lines from hematologic malignancy reflect the characteristics of normal corresponding hemopoietic cells, the hemopoietic stem cells should express mRNA of the ABO blood group.

ABO Blood-Group System↗

PubMed1998

Vinblastine enhancement of hyposmosis-induced catecholamine release in cultured adrenal chromaffin cells: lack of relation to cell swelling and microtubule disruption.

Exposure of chromaffin cells to hyposmotic solution has been shown to cause catecholamine release through the elevation of intracellular Ca2+ level. While cell volume change observed under hyposmotic conditions has been shown to be accompanied by the movement of various ions and suggested to be associated with the reorganization of cytoskeletons. In the present study, the effects of cytoskeleton-disrupting agents on hyposmosis-induced catecholamine release were examined to investigate a possible relationship between catecholamine release and cell volume change under hyposmotic conditions. Hyposmosis-induced catecholamine release was enhanced by pre-treatment of the cells with a microtubule-disrupting agent vinblastine, but not significantly altered by a microfilament-disrupting agent cytochalasin B. Vinblastine also caused an additional increase in the intracellular Ca2+ but failed to affect the cell volume change under hyposmotic conditions. In contrast, the hyposmosis-induced release was not significantly altered by either colchicine, another microtubule-disrupting agent, or taxol, a microtubule-stabilizing agent. These results indicate that vinblastine enhances hyposmosis-induced catecholamine release through an additional increase in the intracellular Ca2+ and furthermore suggest that this effect of vinblastine on the hyposmosis-induced release is unassociated with the disruption of the microtubule system, providing evidence for a lack of the direct relationship between catecholamine release and the cell volume change observed under hyposmotic conditions.

Animals↗

PubMed1998

Role of macrophages in acute murine cytomegalovirus infection.

It has been recognized that macrophages play an important role in controlling virus infection in experimental animal models. To evaluate the role of macrophages in acute murine cytomegalovirus infection, macrophages in the spleen and the liver were eliminated by an intravenous injection of liposomes containing a cytolytic agent, dichloromethylene diphosphonate. The depletion of macrophages led to a significant increase of virus titer in the spleen and lungs in both susceptible BALB/c and resistant C57BL/6 mice during the first three days after intravenous infection. In the spleen, the increase of virus titer in macrophage-depleted BALB/c mice was much greater than that in NK cell-depleted mice. These results suggest that macrophages contribute to protection mainly by the mechanisms which are independent of NK cells during the first three days after infection. The increase of virus titer in macrophage-depleted C57BL/6 mice was as great as that in NK cell-depleted mice because of the high contribution of NK cells to protection in C57BL/6 mice. In the liver in both strains of mice, the effects of macrophage depletion on virus titer were not as much as those in the spleen and lungs. Furthermore, the local depletion of peritoneal macrophages resulted in a great increase of virus titer in the spleen at three days after intraperitoneal infection. We conclude that macrophages greatly contribute to decreasing the virus load in some organs possibly through either or both intrinsic and extrinsic mechanisms in the early phase of primary infection with murine cytomegalovirus.

Acute Disease↗

PubMed1998

Transurethral ureterolithotomy in 100 lower ureteral stones.

A total of 100 patients with lower ureter stones received transurethral ureterolithotripsy (TUL) using a pulsed dye laser and/or a pneumatic lithotriptor. Extracorporeal shock wave lithotripsy treatment was added in 15 patients because fragments larger than 4 mm had been pushed back to the renal pelvis. The median stone size was 8 mm (range 3-22 mm). Operative time ranged between 3 and 157 min with a median of 30 min. Stone size correlated well with impaction, when impaction was defined as the inability of a guidewire to pass over the stone. Complete removal was defined as total clearance at 1 month without retreatment. The overall stone-free rate was 93%. Among the 7 not-stone-free cases, 5 cases were considered to have been treated successfully because asymptomatic residual fragments were smaller than 4 mm, 1 case required retreatment to become stone free, and 1 case with a silent residual fragment of 8 mm had been followed up for 3 months. The success rate was 98% when successful treatment was defined as total clearance or the presence of asymptomatic residual fragments of 4 mm or less without retreatment. Impaction was not a significant determining factor of stone-free rate (95.7 and 86.7%, respectively, p > 0.05) and in situ stone-free rate (TUL alone; 85.7 and 76.7%, respectively, p > 0.05). Two minor ureteral perforations were encountered. No patient required percutaneous nephrostomy or open surgery, or showed any late complications. TUL is a safe and successful method in managing lower ureteral stones.

Adolescent↗

PubMed1998

Expression of growth factor ligand and their receptor mRNAs in bovine ova during in vitro maturation and after fertilization in vitro.

We analyzed the expression of mRNAs for growth factor [epidermal growth factor (EGF), insulin-like growth factor-I (IGF-I), basic fibroblast growth factor (bFGF) and platelet-derived growth factor A chain (PDGF-A)] and their receptor (R) by reverse transcription-polymerase chain reaction in bovine ova during oocyte maturation in vitro (0-21 hr) and after fertilization in vitro (6-144 hr: zygotes to blastocysts). Transcripts for EGF were not found before fertilization. Transcripts for IGF-I were present in immature oocytes immediately after collection and in embryos from the 2-cell stage onward. Transcripts for bFGF were present in all stages of oocyte maturation and after fertilization up to the 16-cell stage. Transcripts for PDGF-A were present in all stages of oocyte maturation and after fertilization up to the 2-cell stage. Transcripts for ErbB3 (a member of the EGF-R subfamily), and bFGF-R were present in all stages of oocyte maturation, after fertilization up to the 2-cell stage, and the blastocyst stage. Transcripts for IGF-I-R and PDGF-Ralpha were present in all stages of oocyte maturation and embryo development. The results of this study showed that eight different messages for growth factor and their receptor were detectable in bovine ova during oocyte maturation and/or after fertilization in vitro and their expression patterns were the gene-specific rather than the developmental stage of bovine ova.

Animals↗

PubMed1998

Effect of MDR antagonists on the cidal activity of vincristine for cells expressing MDR-1 is superior to those expressing MRP.

In an attempt to identify the target protein, P-GP or mrp, of each MDR antagonist, verapamyl (Ver), dipyridamole (Dip), or cyclosporin A (Cy-A), this study was designed to compare the activity of the three afore-mentioned drugs and to test their combined effect on the cidal activity of vincristine (VCR) in five types of wild and the corresponding VCR-resistant cultured cell lines from human leukemia and lymphoma. Three of the VCR-resistant cell lines are characterized by the overexpression of mdr-1, while two cell lines overexpress mrp. We found that all three antagonists additively to synergistically enhanced the cidal activity of VCR for the five wild-type and VCR-resistant cell lines in a dose dependent manner when used singly. Combinations consisting of a 20% inhibitory concentration (IC20) of VCR plus two antagonists also showed additive to synergistic effects on both wild and VCR-resistant cell lines. It is of interest that the combined effect of IC20 VCR plus MDR antagonists on the three VCR-resistant cell lines expressing mdr-1 was significantly superior to those of the two cell lines expressing the mrp gene. These results suggest that the combined effect of MDR antagonists work better than their single use and that the MDR antagonists work more efficiently in cells showing drug resistance through mdr-1 than in those utilizing mrp.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1998

[Topography, size and number of cortical tubers in tuberous sclerosis with West syndrome].

To predict the prognosis of tuberous sclerosis with West syndrome, we studied the relation between the cortical tubers and the neurological evolution. We reviewed the clinical data on the seizure evolution and developmental status of 7 patients (3 males and 4 females) and estimated the number, size and location of cortical tubers on 5 mm-thick T2-weighted MR images. The cortical tubers were grouped into categories: small (10 mm or less in maximum diameter), medium (10 to 25 mm) and large (25 mm or more). The first MRI study was performed at ages form 3 months to 18 years, and the follow-up study was performed on 6 out of the 7 patients. We also estimated the interval change of cortical tubers. The average number of cortical tubers was 12.1 per patient, being larger than the values previously reported for the patients of tuberous sclerosis without West syndrome. However, the numbers varied widely from 1 to 29. Two patients with good outcome had more than 10 tubers, whereas two patients with poor outcome had less than 5 tubers. All the patients with good outcome were female. Follow-up MRI in one patient revealed a marked increase in the number of cortical tubers, from 15 (at the age of 5 months) to 23 (at 4 years 2 months), which probably resulted from physiological hypomyelination during infancy. Some tubers corresponded to a electroencephalographic focus, whereas others did not. There was no difference in the topography of cortical tubers between the patients with good prognosis and those with poor prognosis. Thus, it was hard to make the prognosticate a case of tuberous sclerosis based solely on the number and topography of cortical tubers on MRI.

Cerebral Cortex↗

PubMed1998

[Trends of prostate cancer: comparison between 1986-90 and 1991-95 at Asahi General Hospital].

Patients with prostate cancer treated during 1986-95 were divided into two groups: the first five years as early period and the recent five years as late period. Background factors, therapeutic modality and prognosis were compared between these two groups. The number of patients during the late period (245) was about 1.5 fold that during the early period (161). The average age for each stage are similar within the same period, and also similar between early and late periods. Almost the same ratios were noticed on stage distribution and on histological grade between early and late periods. Therefore, the increase in the number of patients in recent years was due mainly to expansion with the same proportion of background factors. Patients with T2 and T3 during the late period received more aggressive treatments with/without endocrine therapy. Subsequently these patients seemed to show better prognosis than the patients during the early period. No differences in survival of patients with metastosis was revealed between these two periods. Therefore, the outcome was not improved by recent endocrine therapy.

Androgen Antagonists↗

PubMed1997

Correlation between permeability-related glycoprotein expression and susceptibilty to oxygen radicals in vincristine-resistant hematologic cell lines.

This study was designed to test the correlation between the expression of permeability-related glycoprotein (P-GP) and susceptibility to oxygen radicals derived from the reaction of hypoxanthine (HX)-xanthine oxidase (XO) in wild type and vincristine (VCR)-resistant hematologic cell lines. A marked correlation between P-GP expression and susceptibility to oxygen radicals was found in VCR-resistant cells, while it was weak in wild cell lines. In contrast, there was neither correlation between sensitivity to VCR and oxygen radicals nor between sensitivity to VCR and P-GP expression in both wild type and VCR-resistant cells. No correlation between sensitivity to adriamycin or oxygen radicals and P-GP expression were observed in both cells tested. These results may suggest a new mechanism of drug resistance in cells expressing P-GP.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1997

Development of the human principal sensory trigeminal nucleus: a morphometric analysis.

The anatomical development of the principal sensory trigeminal nucleus was assessed with morphometric features using serial celloidin sections of 15 human brains, including 12 brains obtained from fetuses and neonates. A microscope and an optical electronic planimeter combined with a computer were employed for morphometric measurements of columnar areas, neuronal numbers, neuronal areas and neuronal perimeters to statistically analyze and evaluate the development of neuronal densities, neuropil indexes and circularity ratios. We could not detect the principal sensory trigeminal nucleus in the specimen of 12 gestational weeks (GW). Microscopic observation disclosed that the fetal principal sensory trigeminal neurons approached those of the adult around 33 GW in terms of cell arrangements, amounts of Nissl bodies and morphology of neurons. Our morphometric analysis showed that the columnar volume, the neuronal area and the neuropil index increased with gestational age. The neuronal density decreased with gestational age, especially from 16 to 32 GW. Comparing the neuronal area with the columnar volume, it developed before the columnar volume during the fetal period. The neurons of the principal sensory trigeminal nucleus matured around 33 GW under microscopic observation and in terms of the distribution of neuronal areas. The development of the neuropil may accelerate after individual neurons of principal sensory trigeminal nucleus mature.

Adolescent↗