Search PubMed⌕ Search

Biomedical subjects

E Watanabe

Publications and source records attributed to E Watanabe.

At least 55 records · Page 3Linked to original sources
PubMed1998

Effect of basic fibroblast growth factor on angiogenesis in the infarcted porcine heart.

Administration of growth factors is emerging as a new therapeutic approach for the enhancement of collateral vessel formation in the ischemic heart. We have investigated the effects of intramyocardial delivery of FGF-2 in the presence and absence of heparin on angiogenesis in a porcine model of myocardial infarction. Yorkshire pigs were subjected to myocardial infarction by the placement of an embolization coil in the left anterior descending artery (n = 5). Four to five weeks after creation of an infarct, FGF-2 (10 micrograms) alone or in complex with heparin, heparan sulfate, or heparin agarose beads was injected either into the normal myocardium or along the infarct border area. Histologic evaluation of each injection site was performed 4 to 5 weeks post-injection. The effect of FGF-2 on angiogenesis was evaluated by determining the number of capillaries (diameter < 20 microns (and arterioles (> 20 microns with tunica media) in each area observed. The number of capillaries were not affected by the treatment of FGF-2 both in normal myocardium and infarct border area. However, in the normal myocardium, the number of arterioles were increased with the treatment of FGF-2 alone (85 +/- 59%, P < 0.04), FGF-2 plus heparin (281 +/- 193%, P < 0.004) and FGF-2-coated heparin beads (241 +/- 141%, P < 0.01), as compared to control. Delivery of FGF-2 into the infarct border area, also increased the number of arterioles when FGF-2 was given with heparin (736 +/- 154%, P < 0.001) or heparin beads (700 +/- 109%, P < 0.001), as compared to control. FGF-2 administered with heparin was the most effective method of enhancing angiogenesis as compared to FGF-2 alone, FGF-2 plus heparan sulfate, or FGF-2 coated heparin agarose beads.

Affinity Labels↗
PubMed1998

Use of a channel biosensor for the assay of paralytic shellfish toxins.

Gonyautoxin (GTX), saxitoxin (STX) and tetrodotoxin (TTX), also known as paralytic shellfish poisons (PSP), block Na+ channels, including those in the frog bladder membrane. A tissue biosensor has been developed, consisting of a Na+ electrode covered with a frog bladder membrane integrated within a flow cell. The direction of Na+ transfer, investigated in the absence of Na+ channel blockers, established that active transport of Na+ occurs across the frogs bladder membrane from the internal to the external face. Transfer was shown to be TTX sensitive. The tissue sensor response to each of the different PSP was recorded and the results compared with toxicities determined by the standard mouse bio-assay. Using high concentrations of TTX from the puffer fish Takifugu niphobles, a linear correlation was found between the results from the two assay systems. However, the tissue biosensor system was also able to detect very low concentrations of TTX in samples from two species of puffer fish (Takifugu niphobles and Takifugu pardalis) at concentrations below the detection limit of the mouse bio-assay.

Animals↗
PubMed1998

Two types of brain chondroitin sulfate proteoglycan: their distribution and possible functions in the rat embryo.

The distribution of neurocan-like and 6B4 proteoglycan-like immunoreactivities in the rat embryo was investigated from gestational days 10.5-15.5 with monoclonal antibody 1G2 or 6B4 that immunoreacted with neurocan and 6B4 proteoglycan, respectively. In the brain region, the leptomeningeal layer in the myelencephalon, metencephalon, diencephalon or telencephalon was first stained with monoclonal antibody 1G2 at embryonic day 12.5. In the spinal cord, monoclonal antibody 1G2 stained the regions corresponding to the boundary caps (designated the boundary caps) after embryonic day 11.5 and the roof plate after embryonic day 12.5. The intensity of staining in the boundary caps reached a maximum at embryonic day 13.5, at around the time when the axons from the dorsal root ganglia reach this region. However, the points of contact of the axons with the boundary caps were hardly stained. By contrast, the roof plate was most strongly and widely stained at embryonic day 14.5, at around the time when the axons enter the spinal cord. Western blotting of preparations from the spinal cord that included the boundary caps revealed the presence of neurocan in this region. Thus, it is likely that neurocan serves as a barrier molecule to regulate the direction of axonal growth from the dorsal root ganglia. By contrast, in addition to staining of the future brain and spinal cord, monoclonal antibody 6B4 stained the trigeminal and sympathetic ganglia in the rat embryo on and after embryonic day 12.5, as well as the vestibular, facial and dorsal root ganglia after embryonic day 12.5. In studies in tissue culture, monoclonal antibody 6B4 prevented the inhibitory effects of 6B4 proteoglycan on the proliferation of PC12D cells. No immunostaining with monoclonal antibody 6B4 was observed in cells that had incorporated bromodeoxyuridine in vivo. Possible functions of 6B4 proteoglycan in the rat embryo are discussed.

Animals↗
PubMed1998

Cloning and chromosomal mapping of the human gene of neuroglycan C (NGC), a neural transmembrane chondroitin sulfate proteoglycan with an EGF module.

Neuroglycan C (NGC) is a 150 kDa transmembrane chondroitin sulfate proteoglycan with a 120 kDa core glycoprotein that was originally isolated from the developing rat brain. A rabbit antiserum, raised against a recombinant polypeptide representing a protein of the rat NGC core protein, recognized an NGC homolog in homogenates of brains of various vertebrates including humans. Because of the possible involvement of this proteoglycan in the etiology of a human neuronal disease, we cloned a complete coding sequence from a human brain cDNA library using a rat NGC cDNA as a probe. The predicted protein contains 539 amino acids and shows 86% homology with the rat counterpart. The domain structure characteristic of rat NGC was completely conserved in human NGC, which consisted of an N-terminal signal sequence, a chondroitin sulfate-attachment domain, an acidic amino acid cluster, an EGF-like domain, a transmembrane domain and a cytoplasmic tail. Northern blot analysis revealed that a single transcript of 2.4 kb was detectable in the brain, but not in other human tissues. By fluorescence in situ hybridization (FISH) analysis, the human NGC gene was assigned to the chromosomal 3p21.3 band, where the Sotos syndrome has been mapped. Involvement of the NGC gene in the etiology of the Sotos syndrome remains to be examined.

Amino Acid Sequence↗
PubMed1998

Determination of Na channel blockers in paralytic shellfish toxins and pufferfish toxins with a tissue biosensor.

The biosensor consisted of a sodium electrode and covered with the frog bladder membrane within a flow cell was tested for the estimation of tetrodotoxin (TTX) and saxitoxin (STX). This sensor was applied to detect very low amounts of the Na+ channel blockers, STX and TTX, in different shellfishes and swellfishes. A good agreement was obtained between TTX activities determined by mouse assay and amounts of Na+ channel blockers estimated by frog membrane sensor. The lowest level of TTX (fg) that can be determined by frog membrane sensor does not cause human poisoning. The channel blockers in short-necked clam, which was assumed to be STX, were monitored by this sensor continuously every week for one year. It was discovered that the STX content increased from July until September and then decreased from October until March. The biosensor proposed here may be used for the estimation of STX and TTX conventionally in the future.

Animals↗
PubMed1997

Tensile strength of soldered gold alloy joints.

STATEMENT OF PROBLEM: Little information is available about the mechanical properties of soldered gold alloys after they have undergone various heat treatments. PURPOSE: This study investigated the influence of heat treating on the strength properties of soldered joints of two gold alloys (NC Type IV and Sofard), which can be age-hardened at intraoral temperature. MATERIAL AND METHODS: Dumbbell-shaped specimens were cast with each gold alloy and were cut at the center of the connecting bar for soldering. The two halves of the casting were then soldered with two different gold-based solders (Maingold and Degulor). Three different heat treatments were performed on the soldered gold alloy assemblies: solution heat treatment (ST) at 700 degrees C for 5 minutes (treatment A); aging at 37 degrees C for 7 days after ST (treatment B); and aging at 250 degrees C (Sofard) or 400 degrees C (NC type IV) for 15 minutes after ST (treatment C). The tensile strength, elongation and microhardness were evaluated after each heat treatment. RESULTS: The hardness values of Sofard significantly (p < 0.05) increased during aging at 37 degrees C (treatment B) and produced adequate strengths of the soldered joints, especially with the harder solder (645.7 MPa: Degulor [222 VHN] vs. 493.3 MPa: Maingold [165 VHN]). CONCLUSIONS: The results of this study indicated the possibility of strengthening soldered joints in the oral environment, thus eliminating the necessity for any additional hardening heat treatment.

Analysis of Variance↗
PubMed1997

Inhibition of azoxymethane-initiated colon tumor by bovine lactoferrin administration in F344 rats.

The influence of bovine lactoferrin (bLF) on colon carcinogenesis was investigated in male F344 rats treated with azoxymethane (AOM). Following three weekly injections of AOM, the animals received 2 or 0.2% bLF for 36 weeks. No effects indicative of toxicity were noted, but significant reduction in both the incidence and number of adenocarcinomas of the large intestine was observed with both doses. Thus, the incidences of adenocarcinomas in the groups receiving 2% and 0.2% bLF were 15% and 25%, respectively, in contrast to the 57.5% control value (P < 0.01 and P < 0.05, respectively). The results indicate that bLF might find application for chemoprevention of colon cancer.

Adenocarcinoma↗
PubMed1997

Expression of thyrotropin-releasing hormone (TRH) receptor mRNA in somatotrophs in the rat anterior pituitary.

A response of growth hormone (GH) to thyrotropin-releasing hormone (TRH) is observed in lower mammals and patients with diseases such as a cromegaly, but not in normal subjects. We have previously demonstrated the existence of intact TRH receptor mRNA in GH-secreting adenoma. To examine whether intact somatotrophs in the anterior pituitary also express TRH receptor, we attempted to localize both TRHR mRNA and GH immunoreactivity simultaneously. In situ hybridization analysis revealed TRHR mRNAs specifically in the anterior pituitary, and 61.1% of the anterior pituitary cells expressed this transcript. Staining for GH and PRL on the same samples showed that the somatotrophs apparently expressed TRHR mRNA and approximately 62.3% and 30.9% of hybridization-positive cells were somatotorophs and mammotrophs, respectively. Moreover, TRHR mRNA level in the somatotrophs expressed as the number of silver grains per cell was equivalent to that in the mammotrophs. These findings demonstrated expression of the TRHR mRNA in somatotrophs in the rat anterior pituitary, and also showed that more than 50% of the TRHR mRNA detected in the anterior pituitary was derived from these cells.

Animals↗
PubMed1997

[Somatotopical mapping of the human somatosensory cortex with echo-planar MRI].

The somatotopical organization of the somatosensory cortex was analyzed. Echo-planar imaging was used to obtain functional images, and magnetic field strength was 1.5T. Natural stimulation at a frequency of 3 Hz (scrubbing or tapping) was applied to one of the three cutaneous areas: toes, fingertips, and tongue tip. The focal bands which show the significant signal increases were located on the contralateral post-central gyrus, and these changes of signal intensity originate from the cortical parenchyma because there were no major veins in the central sulcus. The focal bands which respond to each stimulation sites were anatomically distinct and located medially-to-laterally in the order of toes, fingertips, and tongue tip.

Adult↗
PubMed1997

[Treatment of acute myelogenous leukemia in patients more than 80 years old].

We studied fifteen patients older than 80 years of age with acute myelogenous leukemia (AML) treated between 1984 and 1996. Among 15 cases of AML including 7 de novo cases and 8 from myelodysplastic syndrome (MDS) or hypoplastic leukemia, 14 patients had complications, including cardiovascular disease, diabetes mellitus or other malignancies. Although patients with de novo AML showed high peripheral WBC counts and higher cellularity of bone marrow than those from MDS or hypoplastic leukemia, it was difficult in some cases to distinguish these types of AML from hematological findings. Of the 6 AML cases, three had entered complete remission (CR) by a standard dose of combination chemotherapy (BHAC-DMP). One CR patient has had CR for more than 9 years now with good QOL. Among the 3 patients treated by low-dose Ara-C, one attained CR but only for a short period. Four other patients received BRM, such as G-CSF or Ubenimex, and 2 patients died without chemotherapy. Since AML at more than 80 years of age is a highly heterogenous disease, it would be reasonable to give antileukemic agents according to the individual patient's condition.

Aged↗
PubMed1996

Involvement of specific macrophage-lineage cells surrounding arterioles in barrier and scavenger function in brain cortex.

The transport of solutes between blood and brain is regulated by a specific barrier. Capillary endothelial cells of brain are known to mediate barrier function and facilitate transport. Here we report that specific cells surrounding arterioles, known as Mato's fluorescent granular perithelial (FGP) cells or perivascular microglial cells, contribute to the barrier function. Immunohistochemical and in situ hybridization studies indicate that, in normal brain cortex, type I and type II macrophage scavenger receptors are expressed only in FGP/perivascular microglial cells, and surface markers of macrophage lineage are also detected on them. These cells mediate the uptake of macromolecules, including modified low density lipoprotein, horseradish peroxidase, and ferritin injected either into the blood or into the cerebral ventricles. Accumulation of scavenged materials with aging or after the administration of a high-fat diet results in the formation of honeycomb-like foam cells and the narrowing of the lumen of arterioles in the brain cortex. These results indicate involvement of FGP/perivascular microglial cells in the barrier and scavenger functions in the central nervous system.

Adult↗
PubMed1996

A membrane-bound heparan sulfate proteoglycan that is transiently expressed on growing axons in the rat brain.

Monoclonal antibodies were raised to membrane-bound proteoglycans derived from rat brain and three monoclonal antibodies that recognized a 200-kDa heparan sulfate proteoglycan (designated H5-PG) with a core glycoprotein of 140 kDa were obtained. The expression of H5-PG was spatially and temporally regulated in the central nervous system. In the cerebellar cortex, H5-PG was associated mainly with the actively growing parallel fibers of granule cells. The expression was abruptly down-regulated in parallel with the formation of synapses on dendrites of Purkinje cells. In the cerebral cortex, the proteoglycan was widely distributed throughout the cortex. The temporal pattern of expression was similar to that in the cerebellar cortex; the peak level of expression was observed during the period from postnatal days 0 to 20 when neuritogenesis and synaptogenesis occur most extensively in the rat cerebral cortex. H5-PG in the central nervous system disappeared prior to adulthood except in the olfactory bulb. High-level expression was recognized on the olfactory nerves and glomeruli, where the renewal of both axons and synapses is occurring constantly. The data suggest that H5-PG is a glycoconjugate on axonal surface that is involved in axonal outgrowth and/or synaptogenesis.

Animals↗
PubMed1996

Non-invasive functional mapping with multi-channel near infra-red spectroscopic topography in humans.

Near-infrared spectroscopy (NIRS) is a new technique for non-invasive monitoring of tissue oxygenation and its kinetics. Up to this date, it has been used solely in research for the global hemodynamic change of the brain and for rough regional activation after stimulating the brain physiologically. This paper describes functional brain mapping using multi channel (ten channel) NIRS by applying the motor stimulation in humans. Our results demonstrate that the regional hemodynamic change was detected in a small area around the motor cortex with a time resolution of 1-2 s. NIRS technique offers considerable potential for research and clinical applications with no invasion.

Adult↗
PubMed1996

Influence of cluster formation of acidic phospholipids on decrease in the affinity for ATP of DnaA protein.

DnaA protein is the initiator of chromosomal DNA replication in Escherichia coli. We examined the influence of artificial mixed membrane composed of synthetic acidic (phosphate) lipid and basic (ammonium) lipid on the affinity of DnaA protein for ATP. Two sets of acidic and basic lipids with distinguishable numbers of hydrophobic alkyl chains were devised. Synthetic membranes made of the sole acidic lipid but not the basic bilayers inhibited the ATP binding to DnaA protein and stimulated the release of ATP from the ATP-DnaA complex. The basic bilayer-forming compounds served as the matrix for the guest acidic lipids. Acidic lipids dispersed in the basic matrix membrane had little effect on ATP binding and on ATP release. Conversely, acidic lipids forming cluster structures in the mixed artificial membranes inhibited the ATP binding and stimulated the release of ATP. These observations suggest that in mixed lipid bilayers, a cluster structure of acidic lipids seems to be an important parameter to decrease the affinity of DnaA protein for ATP.

Adenosine Triphosphate↗
PubMed1996

Spinal intermittent claudication due to cervical and thoracic degenerative spine disease.

STUDY DESIGN: Neurogenic intermittent claudication can be caused by spinal cord compression. In this study, 20 patients with spinal intermittent claudication due to degenerative spine diseases were evaluated. OBJECTIVES: This study clarified the clinical features and pathomechanism of spinal intermittent claudication due to degenerative spine diseases. SUMMARY OF BACKGROUND DATA: Spinal intermittent claudication may either be produced by intrinsic or extrinsic lesions. Little is known about spinal intermittent claudication due to extrinsic lesions such as spinal cord compression. Twenty patients with spinal intermittent claudication, caused by cervical or thoracic lesions, who were given surgical treatment except for one, were studied. Their main subjective symptoms were tightness, weakness, and numbness in the lower limbs and a strangulated sensation in the trunk to lower limbs. The objective findings were occurrence and/or aggravation of spinothalamic signs. METHODS: The gait loading test was performed on these 20 patients. Selective spinal angiography was performed on the patients with thoracic myelopathy and its therapeutic effects were evaluated. A radiographic assessment was made in all patients. RESULTS: The subjective symptoms and objective findings were reproduced by the gait loading test. Selective spinal angiography temporarily relieved or improved the spinal intermittent claudication due to the thoracic myelopathy. Spinal intermittent claudication disappeared immediately after surgical treatment. CONCLUSIONS: Circulatory impairment of the spinal cord seems to be closely related to the etiology of spinal intermittent claudication. Besides providing diagnostic information, selective spinal angiography may also have a temporary therapeutic effect.

Adult↗
PubMed1996

Development of an ultra high sensitive tissue biosensor for determination of swellfish poisoning, tetrodotoxin.

A simple tissue biosensor for measuring Na+ channel blockers such as tetrodotoxin (TTX) and saxitoxin (STX) has been developed. The membrane of frog bladder has Na+ channels which control the passage of Na+. It is well known that TTX blocks Na+ channels. The tissue biosensor consists of a Na+ electrode integrated within a flow cell. The tip of the electrode was covered with frog bladder membrane sandwiched between two sheets of cellulose acetate membrane, and the electrode was set in a flow cell. A solution of 8% NaCl was carried in the cell and the output of the electrode allowed to stabilize. TTX was injected into the sensor system and measured from the inhibition ratio of the sensor peak output. One assay took approximately 5 min. The lower limit of detection was 86 fg. The continuous determination of TTX was feasible for 250 h in the presence of 0.003% NaN3. A Linear correlation was obtained between TTX activities of F-niphobles and F-parudale determined by the methods of TTX sensor and mouse assay.

Animals↗
PubMed1996

Sex and strain differences in constitutive expression of fatty acid omega-hydroxylase (CYP4A-related proteins) in mice.

The constitutive expression of hepatic fatty acid hydroxylase was examined in both sexes of ddY mice by measuring the activities of lauric acid omega-hydroxylase (LAH). The activity of male mice was significantly higher than that of female mice. Such a sex difference of hepatic LAH activity was not observed in other strains of mice, including BALB/c and C57BL/6. To examine whether decreased total P450 activities caused low LAH activity levels in female ddY mice, ethoxycoumarin O-deethylase activity, which is exhibited by many P450s, was measured in both sexes of mice. This activity had no sex difference. The developmental regulation of hepatic fatty acid hydroxylase was then examined by making consecutive measurements of LAH activity in ddY mice. The activity is the same in immature male and female mice, but is differentiated in the sexually mature state. Furthermore, in male mice, orchiectomy caused a dramatic decrease in hepatic LAH activity and the activity was restored by testosterone treatment to the level of the intact animal. In female mice, ovariectomy and estradiol treatment had no effect on the activity, but testosterone treatment caused an increase in the activity. The above data are consistent with the constitutive expression of CYP4A-related proteins measured by using anti-rat CYP4A1 polyclonal antibody. Anti-CYP4A1 antibody inhibited LAH activity, but not lauric acid (omega-1)-hydroxylase activity. These results suggest that some factors associated with male sex hormone are involved in the regulation of hepatic fatty acid omega-hydroxylase in ddY mice.

Animals↗