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Biomedical subjects

M Yamada

Publications and source records attributed to M Yamada.

At least 487 records · Page 27Linked to original sources
PubMed1999

Element content of human umbilical artery and vein in umbilical cord.

To elucidate the element content of newborn blood vessels, umbilical arteries and veins in human umbilical cords, which had the advantage of easy sampling, were examined by ICP-AES. Umbilical cords were removed after birth. Mothers' ages ranged from 26 to 35 yr. It was found that the content of sulfur was the highest in both umbilical arteries and veins, being higher than the content of calcium and phosphorus. With respect of the content of sulfur, calcium, and magnesium, there were significant differences between the arteries and veins.

Aged↗
PubMed1999

A possible balance of phosphorus accumulations among bone, cartilage, artery, and vein in single human individuals.

To elucidate relationships between the decrease of mineral contents in human bones and the accumulation of minerals in the other human tissues, the contents of phosphorus in human bones, arteries, veins, and cartilages in 27 subjects (17 men and 10 women) were analyzed by inductively coupled plasma-atomic emission spectrometry. These were resected from subjects who died in the age range 40-98 yr. Calcanei were chosen for analysis of mineral contents in contrast to arteries such as the femoral, popliteal, and common carotid arteries, veins such as superior and inferior venae cavae, internal jugular, and femoral veins, and pubic symphyses. It was found that the content of phosphorus in calcanei was in agreement with that in both the pubic symphysis and the arteries such as femoral, popliteal, and common carotid arteries, but it was not in agreement with that in the veins such as superior and inferior venae cavae, internal jugular, and femoral veins. This suggests that phosphorus released from bones is accompanied by accumulations of phosphorus in the artery and cartilage.

Adult↗
PubMed1999

Age-independent constancy of mineral contents in human ribs.

On age relationships of mineral contents in human bones, the contents of the sixth rib and a piece of its compact bone were determined by inductively coupled plasma atomic emission spectrometry (ICPS). The ribs were resected from 21 subjects (14 men and 7 women) who died in age ranging from 65 to 93 yr. There were no age-dependent decreases in Ca and P contents of the ribs in the age range on ICPS. It was found that there were no age-dependent decreases in Ca and P in compact bones of ribs.

Age Factors↗
PubMed1999

Age-related changes of elements in human anterior cruciate ligaments and ligamenta capitum femorum.

To elucidate compositional changes of human ligaments by aging, the content of elements in anterior cruciate ligaments (ACLs) and ligamenta capitum femorum (LCFs) was analyzed by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of 11 men and 7 women, ranging from 59 to 91 yr of age. With regard to the content of elements, the content of sulfur and iron was significantly higher in the LCFs than in the ACLs. It was found in the ACLs that the content of sulfur decreased gradually with aging, whereas the content of calcium, phosphorus, and magnesium increased progressively with aging. On the other hand, it was found in the LCFs that the content of magnesium decreased gradually with aging, where as the content of phosphorus increased progressively with aging. The common finding that the content of phosphorus increased with aging, but the content of iron decreased, was obtained in the ACL and LCF. Regarding sexual difference, it was found in both the ACLs and LCFs that the content of phosphorus was higher in women's ligaments than in men's.

Aged↗
PubMed1999

Age-related changes of elements in the human articular disk of the temporomandibular joint.

To elucidate compositional changes of the articular disk (AD) of the temporomandibular joint (TMJ) by aging, elements of the ADs resected from 18 cadavers were determined by inductively coupled plasma atomic-emission spectrometry. It was found that calcium contents of ADs in TMJs increased progressively with aging, whereas the sulfur contents of the ADs decreased slightly with aging. Regarding the content of phosphorus, the contents increased progressively with aging. The study revealed that age-related changes of calcium contents in the ADs of TMJs were similar to those in women's pubic symphyses, but not those in intervertebral disks and menisci.

Aged↗
PubMed1999

Intrathecal 5-fluoro-2'-deoxyuridine (FdUrd) for the treatment of solid tumor neoplastic meningitis: an in vivo study.

To evaluate the possible intrathecal use of 5-fluoro-2'-deoxyuridine (FdUrd) for neoplastic meningitis, its antitumor activity and neurotoxicity in vivo were assessed. FdUrd at doses in the range 5-100 microg/animal was effective against meningeal carcinomatosis using Walker 256 carcinoma cells in rats and MM46 mammary cancer cells in mice and against meningeal gliomatosis using 203 glioma cells in mice. After four intrathecal injections, FdUrd at these doses also showed minimal neurotoxicity in the C57BL/6 mouse brain. To estimate the mechanism of FdUrd efficacy, thymidine phosphorylase (TPase) and thymidine kinase (TK), key enzymes in the metabolism of FdUrd, were measured in rat, mouse and normal human brain tissue, and in human brain tumor tissues and cerebrospinal fluid (CSF) from patients with malignant brain tumors including meningeal carcinomatosis. TPase levels were lower in brain and malignant brain tumors than in other organs and their tumors. Moreover, the activity of TPase in the gray matter of human brain, which faces the cerebrospinal fluid across the cortical surface and into which malignant cells invade in meningeal carcinomatosis, was lower than that in the white matter. TK was undetectable, and TPase was detected (at very low concentrations) in only 4 of 56 patients with brain tumors or meningeal carcinomatosis. These findings indicate that brain tissue and CSF are favorable sites for FdUrd chemotherapy because the rate of conversion of FdUrd to 5-FU would be minimal. In conclusion, FdUrd is potentially useful for intrathecal treatment of neoplastic meningitis from primary brain tumors and systemic cancer.

Animals↗
PubMed1999

Cellular sensitization to cisplatin and carboplatin with decreased removal of platinum-DNA adduct by glucose-regulated stress.

PURPOSE: Stress conditions, such as glucose starvation and hypoxia, that induce glucose-regulated proteins (GRPs) in cells, are seen in most solid tumors. These conditions have been shown to cause cellular resistance to multiple anticancer drugs, such as etoposide, doxorubicin, and camptothecin. We examined the effect of the GRP-inducing conditions on cellular sensitivity to cisplatin and carboplatin, which are widely used drugs against solid tumors. METHODS: We generated the GRP-inducing culture conditions by exposing cells to 2-deoxyglucose (2DG), calcium ionophore A23187 and tunicamycin, and examined cellular sensitivity to cisplatin and carboplatin under these conditions. We next measured platinum accumulation and DNA-bound platinum in 2DG-stressed cells after cisplatin exposure. RESULTS: The GRP-inducing stress conditions led to cellular sensitization to cisplatin and carboplatin. This sensitization was reversible, as the cellular sensitivity returned to normal levels 12 h after removal of 2DG. Platinum accumulation and DNA-bound platinum that were found immediately after exposure to cisplatin for 1 h were slightly increased in 2DG-stressed cells as compared with nonstressed cells. After a drug-free recovery incubation of 8 h, the DNA-bound platinum in the nonstressed cells was reduced by 33% while the amount in the 2DG-stressed cells was sustained at the initial levels. CONCLUSIONS: These results indicated that the decreased removal of platinum-DNA adducts was associated with increased sensitivity to cisplatin and carboplatin in the stressed cells. The sensitization of cancer cells under the GRP-inducing stress conditions would explain, in part, the clinical potency of platinum drugs against solid tumors.

Antineoplastic Agents↗
PubMed1999

Immunohistochemical, conventional and immunoelectron microscopical characteristics of periodic acid-Schiff-positive granules in the mouse brain.

Periodic acid-Schiff-positive granules (PGs) appear in the mouse brains in relation to advancing age. The exact location and pathophysiological significance of PGs, however, are not fully understood. The incidence, staining properties, and topographical distributions of PGs in the brains of 17 AKR mice ranging in age from 7 to 18 months were examined histochemically and immunohistochemically using antibody KM279 raised against a polyglucosan. In addition, to define the precise site of PG formation, we investigated the brains of 4 AKR mice of 24 months of age using conventional and immunoelectron microscopy. PGs were seen in all mice examined and the levels were increased with age. The PGs were located predominantly in the hippocampus and, to a lesser extent, in the cerebellum and olfactory bulb. Immunohistochemically, PGs in the hippocampus and cerebellum were labeled uniformly with KM279. On immunoelectron microscopy with this monoclonal antibody, the fibrillar or membranous structures corresponding to PGs seen using light microscopy were labeled specifically with gold particles. With conventional electron microscopy, fibrillar or membranous structures were seen along with synaptic vesicles and dense-core granules. Moreover, around the cells containing PGs, a few synaptic junctions with neighboring cells were observed, indicating that the cells contributing to formation of PGs were neuronal cells. The positive immunoreactivity of AKR mouse PGs for the antibody KM279 suggests that the PGs and similar structures in other species may share a common antigenicity. Thus, it is assumed that PGs in AKR mice might result from some abnormalities in glucose metabolism.

Age Factors↗
PubMed1999

A patient who survived total colonic type ulcerative colitis complicated by toxic megacolon, disseminated intravascular coagulation, methicillin-resistant Staphylococcus aureus infection and bilateral femoral phlebothrombosis.

We report a patient who survived total colonic type ulcerative colitis (UC) complicated by toxic megacolon (TM), disseminated intravascular coagulation (DIC), methicillin-resistant Staphylococcus aureus infection, and phlebothrombosis. A 69-year-old man was treated for about 4 months under the diagnosis of ischemic colitis at another hospital, and was transferred to our hospital. Based on endoscopic and pathological findings, we strongly suspected UC, and administered salazosulfapyridine and methylprednisolone, but TM and DIC developed, necessitating urgent subtotal colectomy. Despite his elderly age and the severe complications, he recovered and was discharged from our hospital about 4 months after admission. The mortality rate of UC complicated by TM and DIC in elderly patients is high, necessitating rapid initiation of high-dose steroid administration or surgical treatment.

Aged↗
PubMed1999

Intracellular localization of the UL31 protein of herpes simplex virus type 2.

We studied intracellular localization of the UL31 protein of herpes simplex virus type 2 (HSV-2) in infected and transfected cells. The UL31 protein localized diffusely throughout the nucleus in infected Vero cells and the distribution patterns of the UL31 protein appeared to be different from those of either replication protein ICP8 or capsid protein ICP35. In transfected Vero cells it localized diffusely throughout the nucleus except the nucleolus at early times after transfection. At very low efficiency, it accumulated in the nucleolus. At intermediate times after transfection, the UL31 protein showed punctate staining in the nucleus. These punctate forms fused and became larger. At later times after transfection, granular forms further fused and a nuclear diffuse pattern virtually disappeared. We also constructed five N and C terminal deletion mutants of the UL31 protein for transfection assays and showed that the region containing amino acids 44 to 110 was important for nuclear and nucleolar localization. Moreover, green fluorescent protein (GFP)-targeting experiments showed that the UL31 protein was able to transport nonnuclear GFP to the nucleus and nucleolus as a fusion protein.

Animals↗
PubMed1999

High expression of doublecortin and KIAA0369 protein in fetal brain suggests their specific role in neuronal migration.

The X-linked subcortical laminar heterotopia and lissencephaly syndrome is a disorder of neuronal migration caused by a mutation in XLIS, a recently cloned gene on chromosome Xq22.3-q23. The predicted protein product for XLIS, doublecortin (DC), shows high homology to a putative calcium calmodulin-dependent kinase, KIAA0369 protein (KI). Here we identified DC and KI in the brains of human and rat fetuses by immunochemical and immunohistochemical means. In this study, Western blotting demonstrated that both DC and KI are specific to the nervous system and are abundant during the fetal period, around 20 gestational weeks in humans and embryonic days 17 to 20 in rats. Immunostaining of the developing neocortex disclosed localization of DC and KI immunoreactivities in neuronal cell bodies and processes in the zones of ongoing neuronal migration. Although KI showed a somewhat wider distribution than DC, the temporal and spatial patterns of their expression were similar. These results suggest that DC and KI participate in a common signaling pathway regulating neuronal migration.

Animals↗
PubMed1999

Identification of an autoimmune enteropathy-related 75-kilodalton antigen.

BACKGROUND & AIMS: We have previously reported a 75-kilodalton autoantigen specific to X-linked autoimmune enteropathy (AIE) associated with tubulonephropathy. The aim of this study was to identify the autoantigen. METHODS: Complementary DNA (cDNA) clones were isolated by immunoscreening a human duodenal cDNA-expression library with serum from a patient with AIE. RESULTS: cDNA encoding the 75-kilodalton antigen (AIE-75) was identified. The composite nucleotide sequence of the cDNA for AIE-75 was 2214 base pairs long and encoded 552 amino acids. The genomic sequence of AIE-75 was found in Sequence DataBank, which consisted of 21 exons and was located on the chromosome 11p14.3. Recombinant AIE-75 specifically reacted with sera from 3 of 4 unrelated patients with AIE but not with 58 control sera. AIE-75 was predominantly distributed in the epithelial cells of the luminal surface and the upper half of the crypts of the intestine and in the proximal renal tubulus. Similarity searches revealed that the AIE-75 cDNA sequence was an authentic form of several colon cancer-related cDNAs of unknown function. The deduced amino acid sequence contained 3 conserved PSD-95/Dlg/ZO-1 (PDZ) domains. CONCLUSIONS: AIE-75 is a PDZ domain-containing protein expressed in the differentiated epithelial cells of the intestine and kidney and may be involved in protein-protein interaction. The identification of the autoantigen may prove useful in the approach to the pathogenesis of this poorly understood disease.

Amino Acid Sequence↗
PubMed1999

Ruptured anterior spinal artery aneurysm: a case report.

BACKGROUND: Spinal artery aneurysms are rare, and are usually found in association with arteriovenous malformations or coarctation of the aorta. CASE REPORT: A 42-year-old man with a ruptured anterior spinal artery aneurysm is presented here. He experienced subarachnoid hemorrhage, which was confirmed by computed tomography. Magnetic resonance imaging revealed an aneurysm in front of the upper part of the medulla. Angiography demonstrated bilateral vertebral artery occlusion. Distal vertebral arteries and the basilar artery were perfused via the dilated anterior spinal artery, which originates in the right subclavian artery. The aneurysm was located at the distal part of the anterior spinal artery, and was successfully clipped through a lateral suboccipital craniotomy 2 months after bleeding from the aneurysm. After rehabilitation, the patient was able to walk with no apparent neurologic deficit. CONCLUSIONS: This case suggests that the anterior spinal artery as a collateral route after bilateral vertebral artery occlusion is under hemodynamic stress, resulting in aneurysm formation and rupture.

Adult↗
PubMed1999

Allopurinol, an inhibitor of xanthine oxidase, improves the development of IVM/IVF bovine embryos (>4 cell) in vitro under certain culture conditions.

To determine the origin of free oxygen radicals in the culture medium of bovine embryos, the effect of allopurinol, an inhibitor of xanthine oxidase, on the development of embryos (>4 cell) in modified synthetic oviduct fluid (m-SOF) medium was examined. When embryos were cultured in the presence of 0.2 mM allopurinol under high oxygen tension (5% CO2 in air), the blastocyst rate significantly (P<0.05) increased compared with the absence of allopurinol (allopurinol (+) 42 vs. (-) 25%; Day 6, 63 vs. 51%; Day 7, 69 vs. 58%; Day 8). However, allopurinol had no effect on embryo development under low oxygen tension (5% CO2, 5% O2, 90% N2). Moreover, it was found that the developmental rate and the total cell number of blastocysts decreased (development rate: 60 vs. 28%, cell number: 132 vs. 74) when the embryos were cultured in medium containing 0.01 U/mL xanthine oxidase (XOD) and 0.1 mM hypoxanthine (HXT), and the damaging effect of XOD and HXT was removed by the addition of 0.2 mM allopurinol. The beneficial effect of allopurinol was also observed when the glucose concentration was increased to 4.5 mM from 1.5 mM (control: 22% vs. allopurinol: 34%; Day 8), but no beneficial effects were observed in the media without glucose (control: 55% vs. allopurinol: 59%). Taken together, these results suggested that a portion of the free oxygen radicals are generated from the XOD and HXT reactions under culture conditions, and this generation is enhanced by high oxygen tension in the gas atmosphere or by high glucose concentrations in the medium.

Allopurinol↗
PubMed1999

Ultrasound-guided follicle aspiration: the collection of bovine cumulus-oocyte complexes from ovaries of slaughtered or live cows.

To increase the collection efficiency of bovine cumulus-oocyte-complexes (COCs) by transvaginal aspiration, the effects of aspiration pressure and needle diameter on bovine follicular oocyte collection were assessed. Oocytes were aspirated from ovaries of slaughtered cows using 2 different diameter needles (18- or 21-gauge) with 4 different aspiration pressures (40, 80, 120 or 160 mmHg) and of live cows using 18-gauge needles with 40 or 80 mmHg, or using 21-gauge needles with 80 or 120 mmHg. The recovered oocytes were divided into 4 categories according to the surrounding cumulus cells and quality of oocytes: 1) 4 or more layers, 2) between 1 and 3 layers, 3) completely or partially denuded and 4) all others, including expanded cumulus cells and degenerated oocytes. The highest oocyte recovery rates from Categories 1 and 2 were obtained using 18-gauge needles with 40 mmHg pressure and 21-gauge needles with 120 mmHg pressure, respectively, from the ovaries of slaughtered cows. When oocytes were collected from live cows, the highest recovery rates for Categories 1 and 2 were obtained using an 18-gauge needle and 40 mmHg pressure, and 21-gauge needle and 80 mmHg, respectively. In addition, the proportion of oocytes in each category were compared between ovaries from slaughtered and live cows. The proportion of Category 1 oocytes collected from live cows was lower than from slaughtered cows when 18-gauge needles at 80 mmHg (P<0.05). The results show that the combination of aspiration pressure and needle diameter is crucial for COC collection, and they suggest that optimal aspiration conditions for ovaries of slaughtered cows are not necessarily applicable to live cows.

Animals↗
PubMed1999

Brain-derived neurotropic factor prevents superoxide anion-induced death of PC12h cells stably expressing TrkB receptor via modulation of reactive oxygen species.

In our previous report (Satoh et al., 1999. Regulation of reactive oxygen species by nerve growth factor but not by Bcl-2 as a novel mechanism of protection of PC12 cells from superoxide anion-induced death. J. Biochem. 125, 952-959), we reported that nerve growth factor (NGF) protected PC12 cells from superoxide anion (O2-)-induced cell death through a novel regulation of reactive oxygen species (ROS) which increased O2- and decreased hydrogen peroxide (H2O2), indicating that decreasing conversion from O2- to H2O2 is a critical process for the protection by NGF. In the present study, we performed a comparative study on protective mechanisms between NGF and brain-derived neurotrophic factor (BDNF) using TrkB-expressing PC12h cells. When compared with NGF, BDNF induced a weaker but significant protective effect on the cells from O2- induced death. BDNF did not seem to change the total amount of ROS in the cells treated with xanthine and xanthine oxidase. On the other hand, BDNF increased O2- and decreased H2O2- levels in the same cells, although not so strongly as NGF. These results suggest that decreasing conversion from O2- to H2O2 is also critical for the protection by BDNF, which is considered to play a central role in survival and differentiation of CNS neurons.

Animals↗