Biomedical subjects
Publications and source records attributed to H Takamura.
The expression of the c-erbB-2 mRNA in human embryonic lung fibroblasts, a gastric cancer cell line, mature placenta, and 25 gastric cancer tissues was examined by using the polymerase chain reaction following reverse transcription. This technique can be used to examine c-erbB-2 mRNA expression in a small endoscopic biopsy specimen before surgery.
An immunohistochemical study for transforming growth factor-alpha (TGF alpha) and epidermal growth factor receptor (EGFR) was made with 167 primary tumors of advanced gastric cancer to demonstrate the potential existence of autocrine mechanism. TGF alpha stained positively in 87 (52%), and EGFR in 68 (41%) of the tumors. The authors classified the tumors into the following three groups: group 1 with neither TGF alpha nor EGFR staining positively (63 tumors); group 2 with either TGF alpha or EGFR staining positively (53 tumors); group 3 with both TGF alpha and EGFR staining positively (51 tumors). The incidence rates of macroscopically infiltrative tumors and large tumor measuring 6 cm or more in diameter were significantly higher for group 3 than for groups 1 and 2. The patients of group 3 had the poorest prognosis, with a 5-year survival rate of only 12%, while the 5-year survival rates were 45 and 36% for groups 1 and 2. There was a significant difference in survival between the patients of group 1 and those of group 3. Bromodeoxyuridine labeling indices were significantly higher in the tumors belonging to group 3 (median 15.8%) than in those of group 1 (median 10.8%). The results suggest that the autocrine mechanism between TGF alpha and EGFR may play an important role in the progression of gastric cancer, and that when such a mechanism becomes operative, prognosis may be poor.
Basilar and right vertebral artery occlusion, which caused a brain stem infarction, occurred in an 11-year-old boy. There have been nine previous cases of basilar artery occlusion with steno-occlusive lesion in the vertebral artery. It is suspected that dissection of the vertebral artery at the atlantoaxial level and a gradual progression of arterial dissection to the basilar artery were the major causes of this infarction.
A case of a dissecting aneurysm of the left posterior inferior cerebellar artery caused by giant cell angiitis is presented. A 22-year-old woman was admitted on August 30, 1990, with sudden onset of severe occipital headache and vomiting. Neurological examination on admission only showed severe meningismus. CT scan demonstrated subarachnoid hemorrhage and a small hematoma in the 4th ventricle. A left vertebral angiogram demonstrated that the left posterior inferior cerebellar artery was occluded at the lateral medullary segment. We diagnosed subarachnoid hemorrhage from a dissecting aneurysm. On the day following admission, the patient underwent a left suboccipital craniectomy. The posterior inferior cerebellar artery was enlarged for a distance of about 8 mm and there was typical purplish-red appearance in the dissecting aneurysm. This aneurysm was excised after trapping. The histological diagnosis was primary localized giant cell angiitis without systemic involvement. The etiology of the intracranial dissecting aneurysm is obscure, but this report suggests that cerebral angiitis can be considered as an important factor.
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Soybean seeds contain three lipoxygenase isozymes. The functions of these lipoxygenase isozymes in n-hexanal generation were investigated by using mutant lines which lack two or three isozymes. In the presence of linoleic acid, the level of n-hexanal produced was highest in the lipoxygenase-1, -3 double deficient line, followed by the lipoxygenase-2, -3 double deficient, wild type, and lipoxygenase-1, -2, -3 triple deficient lines in that order, and lowest in the lipoxygenase-1, -2 double deficient line. This suggests that lipoxygenase-3 itself cannot produce the n-hexanal precursor and inhibits the n-hexanal generation through other pathways.
A highly sensitive method was developed for quantitative analysis of phospholipid molecular species. Diradylglycerols prepared from phospholipids with phospholipase C were converted to the anthroyl-diradylglycerol derivatives, which could be separated into molecular species and sensitively quantified by reverse-phase HPLC using a fluorescence detector. All the molecular species of the derivatives had the same peak area per mole, and the peak areas were proportional to the amounts of the derivatives. Quantification could be carried out at the femtomole level.
Molecular species of several phospholipid classes and subclasses were quantitatively determined in human umbilical artery and vein endothelial cells. Both types of endothelial cells were similar in phospholipid class composition, whereas they were markedly different in phospholipid subclass and molecular species composition. The amounts of two ether subclasses in phosphatidylcholine and phosphatidylethanolamine were higher in artery endothelial cells than those in vein endothelial cells. The relative content of alkylacyl subclass in phosphatidylcholine, a precursor of platelet-activating factor, was about three times higher in artery endothelial cells than in vein endothelial cells. In artery endothelial cells, arachidonic acid was in highest amounts in alkenylacyl phosphatidylethanolamine, followed by diacyl phosphatidylcholine, diacyl phosphatidylethanolamine, and phosphatidylinositol. In the vein endothelial cells, arachidonic acid was highest in phosphatidylinositol, followed by diacyl phosphatidylethanolamine, diacyl phosphatidylcholine, and alkenylacyl phosphatidylethanolamine. Artery endothelial cells had higher amounts of molecular species containing arachidonic acid than vein endothelial cells in all phospholipid classes and subclasses. These differences are thought to reflect the functional differences of artery and vein endothelial cells.
Molecular species of diacyl, alkenylacyl, and alkylacyl subclasses in human platelet phospholipids were quantitatively analyzed. Dinitrobenzoyldiradylglycerol derivatives prepared from phosphatidylcholine and phosphatidylethanolamine were separated into subclasses by TLC or normal-phase HPLC. Each subclass consisting of more than 20 molecular species was quantified by reverse-phase HPLC with the eluting solvent of acetonitrile-2-propanol (80 : 20). The retention times of molecular species in the alkenylacyl and alkylacyl subclasses were approximately 1.24 and 1.56 times as long as that of the diacyl type. Phosphatidylcholine contained mostly diacyl subclass (94.5%) and small amounts of alkenylacyl (0.8%) and alkylacyl (4.7%) subclasses, while phosphatidylethanolamine was comprised of 44.2% diacyl, 54.4% alkenylacyl, and 1.4% alkylacyl subclasses. The diacyl subclass of phosphatidylcholine mainly consisted of monoenoic and dienoic molecular species, whereas the other subclasses of phosphatidylcholine and all subclasses of phosphatidylethanolamine were mostly comprised of polyenoic molecular species. The distribution of arachidonic acid-containing molecular species in the diacyl, alkenylacyl, and alkylacyl subclasses were 18.7, 48.2, and 47.9%, respectively, in phosphatidylcholine, and 60.1, 63.0, and 46.9% in phosphatidylethanolamine. Hence, the alkylacyl and alkenylacyl subclasses of phosphatidylcholine seem to play physiological roles different from the diacyl subclass in human platelets.
In an advanced stomach cancer with recurrence of regional lymph node metastasis, cis-diamminedichloro-platinum (CDDP) was administered intravenously (IV) according to the following doses and schedules. This treatment schedule consisted of CDDP at a dosage of 100 mg/body/time. This dosage was infused seven times for 24 months (total CDDP dose, 700 mg/body). The overall response rate to chemotherapy was determined as follows. Partial response (PR) was defined as a reduction of at least 50% in the sum of the products of the two greatest perpendicular diameters of all measurable lesions within 15 months of commencing therapy and the absence of disease progression elsewhere. The 56-year-old, male patient is being treated with an outpatient regimen at our Hospital.
The thromboxane A2 antagonist, ONO-3708, completely inhibited the increase in cytosolic free Ca2+ in human platelets during activation with collagen. Half-maximal Ca2+ release and influx required about 3 and 4 nM STA2, a stable thromboxane A2 mimetic, respectively. However, half maximal activation of phospholipase C required about 18 nM STA2. This suggests that thromboxane A2 directly causes Ca2+ mobilization without further activation of phospholipase C during activation of human platelets with collagen.
The Ca2+ channel blocker, nifedipine, a dihydropyridine derivative, inhibited the Ca2+ influx and release from internal stores caused by collagen or a low concentration of the thromboxane A2 (TXA2) analogue, 9,11-epithio-11,12-methano-TXA2 (STA2) (10 nM), but did not inhibit those caused by thrombin or a high concentration of STA2 (100 nM). These results indicate the presence of two distinct, dihydropyridine-sensitive and insensitive, Ca2+ channels dependent on the concentrations and classes of agonists in human platelets.
The presence of cysts within the sacral spinal canal, so-called sacral cysts, is described in literature. These include 'sacral perineural cyst', 'sacral extradural cyst', 'occult intrasacral meningocele' and 'anterior sacral meningocele'. Sacral perineural cyst in these cystic disorders was first described as an incidental autopsy finding by Tarlov in 1938. Since then, several reports have been made describing the sign and symptom, neurological findings, roentgenographic diagnosis and cause and origin of the sacral perineural cysts, although many problems are not yet solved satisfactorily. This cyst occurs on the extradural components of sacral or coccygeal nerve roots. Although most are asymptomatic, these occasionally cause low back pain, sciatic and sacrococcygeal pain, sensory and motor disturbance in the lower extremities, and urinary dysfunction, which symptoms are similar to those brought on by lumbar disc herniation. In 1948, Tarlov reported a case of sciatic pain due to a perineural cyst, the removal of which relieved the symptoms. Symptoms occur because adjacent nerve roots are impinged upon by the thin-walled, fluid-filled cysts, which are formed in a space between the endoneurium and the perineurium. Microscopically, the cyst walls consist of peripheral nerve fibers or ganglionic cells covered with meningeal epithelium. Communication of the cyst with subarachnoid cerebrospinal fluid may be poor, but myelogram and CT myelogram demonstrate the cysts filling with contrast media. With the advent of magnetic resonance imaging (MRI), imaging of the sacral perineural cysts has improved. Recently we had the opportunity to evaluate a patient in whom perineural cysts had caused considerable erosion of the sacrum.(ABSTRACT TRUNCATED AT 250 WORDS)
Mass changes in the various molecular species of phospholipids were determined after stimulation of human platelets with thrombin and collagen. Upon stimulation, every molecular species of phosphatidylinositol and phosphatidylserine was equally hydrolyzed, whereas the molecular species of phosphatidylcholine and diacyl- and alkenylacylphosphatidylethanolamine containing arachidonic acid were selectively hydrolyzed. At low Ca2+ concentrations, which result from mobilization of intracellular Ca2+ stores, phosphatidylinositol, phosphatidylcholine, and diacylphosphatidylethanolamine were hydrolyzed after stimulation with thrombin, whereas only phosphatidylinositol was hydrolyzed with production of thromboxane B2 after stimulation with collagen. At high Ca2+ concentrations, phosphatidylcholine and diacylphosphatidylethanolamine were hydrolyzed after stimulation with collagen, and phosphatidylserine and alkenylacylphosphatidylethanolamine were degraded after stimulation with both thrombin and collagen. [1-14C]Arachidonic acid was heterogeneously incorporated into the individual molecular species of the various phospholipid classes, indicating that the determination of mass is essential for an accurate picture of phospholipid hydrolysis. The data reported here indicate that the Ca2+ concentration affects the differential degradation of phospholipid molecular species in activated human platelets.
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The aminergic and cholinergic innervation of choroid plexuses in three species of amphibia was investigated. Plexuses of the Japanese toad and the bullfrog had poor innervation by adrenergic nerves of sympathetic origin, but in the clawed toad, these plexuses were heavily innervated by adrenergic axons from ganglion cells located in the plexus stroma. Nerve fibers positive for acetylcholinesterase were not found in the plexuses, except for a few fibers with very weak enzyme activity in the clawed toad.
The quantitative analysis of phospholipid molecular species containing polyenoic fatty acids is described. Dinitrobenzoyl derivatives of diacylglycerols prepared from phospholipids were separated into individual molecular species by reversed-phase high performance liquid chromatography (HPLC) using a combination of two solvent systems and were quantified at 254 nm. Thirty-six molecular species were resolved from the phosphatidylcholines of rat hearts, human platelets and Chinese hamster V79-R cells. The derivatives of alkenylacyl molecular species from platelet phosphatidylethanolamine were resolved concomitantly with diacyl molecular species.