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Biomedical subjects

E Yamada

Publications and source records attributed to E Yamada.

At least 127 records · Page 7Linked to original sources
PubMed1988

Intraepithelial nerve fibers in the rabbit ocular ciliary epithelium.

Ciliary processes, mainly iridial processes, of the adult rabbit eye were examined by electron microscopy. Intraepithelial nerve fibers were recognized in the ciliary epithelium. These were single, naked unmyelinated nerve fibers found between pigmented epitheliocytes but not between non-pigmented epitheliocytes. They displayed a beaded structure and contained in their dilated portions many clear vesicles, a few cored vesicles and filamentous mitochondria. Their possible functional significance is discussed.

Animals↗
PubMed1987

A new solid-phase synthesis of oligoribonucleotides by the phosphoro-p-anisidate method using tetrahydrofuranyl protection of 2'-hydroxyl groups.

Six nonaribonucleotides containing the 5'-splice site, one complementary nonamer and an octadecamer containing the 3'-splice site have been synthesized on a polymer support using the phosphoro-p-anisidate method. A 5'-linked 2'-O-tetrahydrofuranyl-N-protected nucleoside 3'-(o-chlorophenyl)phosphoro-p-anisidate was used as the starting nucleotide, and the chain elongated in the 3'-direction by removing the p-anisidate protecting group with isoamyl nitrite under neutral conditions. The octadecamer has been synthesized using dinucleotide blocks and a 3'-terminal trinucleotide.

Base Sequence↗
PubMed1987

In vitro production of human antibodies specifically reactive with human gastric cancer cells of established lines and autologous tissues.

Human lymphocytes derived from regional lymph nodes adjacent to the primary gastric cancer were transformed with Epstein-Barr virus (EBV) to establish lymphoblastoid cell lines secreting human antibodies reactive with cell surface antigens expressed on the gastric cancer cells. The EBV transformation technique was applied to lymph node lymphocytes obtained from 4 gastric cancer patients. As a result of mass screening with the radioactive cell binding assay for the production of anti-gastric cancer related antibodies, one culture (TGc-106) among 1,400 microcultures was identified to secrete human antibody specifically reactive with an established human gastric cancer cell line as target (MKN-45). Furthermore, it was demonstrated with the autologous assay system by the histoimmunofluorescence method that cell surface antigens of autologous gastric cancer cells could be clearly defined with human antibody from one culture (TEb-079) out of 470 microcultures established from a gastric cancer patient (GCP-26); there was no reactivity against the surrounding normal cells constructing the gastric wall. The immunoglobulin class of the human antibodies produced both in TGc-106 and TEb-079 was determined from immunodiffusion tests to be IgM.

Adenocarcinoma↗
PubMed1987

Ultrastructure of the synaptic ribbons in photoreceptor cells of Rana catesbeiana revealed by freeze-etching and freeze-substitution.

The three-dimensional structure of synaptic ribbons in photoreceptor cells of the frog retina was studied with freeze-etching and freeze-substitution methods, combined with a rapid-freezing technique. Although the synaptic ribbon consisted of two electron-dense plaques bisected by an electron-lucent layer in conventional thin sections, such lamellar nature was not so evident in freeze-etched replicas. The cytoplasmic surfaces of the synaptic ribbon presented an extremely regular arrangements of small particles 4-6 nm in diameter. Fine filaments 8-10 nm in diameter and 30-50 nm in length connected synaptic vesicles and the ribbon surface. These connections were mediated by large particles on both ends of the filaments. Approximately 3-5 filaments attached to one synaptic vesicle. Synaptic ribbons were anchored to a characteristic meshwork underlying the presynaptic membrane via another group of similar fine filaments. The meshwork seemed to be an etched replicated image of the presynaptic archiform density observed in thin sections.

Animals↗
PubMed1987

[A study on UFT concentration in tissues and serum of patients with malignant gynecologic tumors following oral administration].

UFT was orally given at a dose of 200 mg twice a day to seven female patients with malignant gynecological tumors. Measurements of blood and tissue concentrations of tegafur (TF), fluorouracil (FU) and uracil (U) showed that the concentrations of both FU and U were clearly increased. The ratio of concentration in the tumor to that in peripheral blood was 9.3, while that of the concentration in the internal iliac lymph nodes to that in the internal iliac artery was 11.2. The changes in blood levels of the three compounds were determined one and five days after UFT administration. There was a distinct difference in the blood levels of the drug among TF, FU and U. TF reached its peak concentration two hours after breakfast and four hours after supper; both FU and U reached their peak concentrations two hours after breakfast and one hour after supper. Furthermore, TF showed a tendency to accumulate after continuous administration, but this was not the case with FU or U. These findings suggest that even during continuous administration, the blood level of FU remains low.

Administration, Oral↗
PubMed1986

Effects of weakly basic amines on proteolytic processing and terminal glycosylation of secretory proteins in cultured rat hepatocytes.

We examined the effects of weakly basic amines on the secretion and post-translational modifications of secretory proteins in cultured rat hepatocytes. Weakly basic amines such as methylamine, chloroquine and NH4Cl strongly inhibited not only protein secretion, but also the proteolytic conversion of a proform of complement C3, allowing the precursor to be released into the medium. The amines, however, had no effect on the proteolytic conversion of prohaptoglobin into its subunits. Since available evidence indicates that the conversion of pro-C3 occurs at the Golgi complex while that of prohaptoglobin takes place in the endoplasmic reticulum, it is most likely that the weak bases specifically affect the proteolytic event occurring at the Golgi complex. Electron microscopic observations confirmed that the amines caused morphological changes of the Golgi complex, consisting of dilated cisternae and swollen vacuoles. When the glycosylation of alpha 1-protease inhibitor and haptoglobin was examined, it was found that the amines caused a marked accumulation in the cells of both glycoproteins corresponding to the mature secreted forms. Neuraminidase digestion demonstrated that the glycoproteins accumulating in response to the amines had acquired terminal sialic acid. The results indicate that the amines do not significantly affect terminal glycosylation, in contrast with their definite effect on proteolytic processing, despite the fact that both modifications take place in the Golgi complex.

Amines↗
PubMed1986

Elastase, collagenase, and cathepsin D activities in the aortas of spontaneously hypertensive and renal hypertensive rats.

In an attempt to clarify the roles of proteases in the developmental mechanisms of hypertensive vascular lesions, changes in activities of aortic elastase, collagenase, and cathepsin D in spontaneously hypertensive rats (SHR) and renal hypertensive rats were biochemically investigated. In SHR, elastase activity initially showed a significant increase, once two-fold higher than that in the control; but the activity tended to decrease earlier than that in the control. In both SHR and normotensive control rats collagenase activities tended to increase with advancing age. The activity in SHR was two-fold higher than that in the control at all ages examined. In both younger SHR and normotensive rats cathepsin D activities proved to be increased with advancing age, while in old rats the activities tended to decrease. The activity in SHR was three- to fivefold higher than that in the control at all ages examined. In renal hypertensive rats, the activities of elastase, collagenase, and cathepsin D increased gradually with increasing blood pressure, at levels significantly higher than those in the control. These findings suggest that the metabolisms of proteins such as elastin and collagen, expressed by these enzyme activities, are accelerated under hypertensive conditions.

Aging↗
PubMed1986

Early changes of experimentally induced cerebral aneurysms in rats. Light-microscopic study.

The changes of the anterior cerebral artery/olfactory artery junction, one of the favorite sites of aneurysm formation, in rats treated with unilateral ligation of the common carotid artery and renal hypertension were investigated by light microscopy. The initial changes of aneurysm occurred not at the apex itself, but on the distal side of the major branch adjacent to the apex, at the intimal pad and the neighboring distal portion. Here the internal elastic lamina showed various degenerative changes and disappearance. The neighboring distal portion adjacent to the intimal pad showed a shallow depression associated with a thinning of the media due to a decrease of medial smooth muscle cells in number even in some control animals. Such degenerative changes of the internal elastic lamina and medial smooth muscle cells caused by hemodynamic stress due to branching structure, including intimal pads, augmented by the experimental treatment, are supposed to be the basis for aneurysm formation.

Animals↗
PubMed1985

Total pelvic exenteration for advanced carcinoma of the lower colon.

Thirteen patients with advanced carcinoma of the lower colon and no evidence of extrapelvic metastasis were submitted to total pelvic exenteration. Nine of the 13 patients had ureteral urinary diversion by the ileal segment conduit. Three had colonic conduit bladder using the terminal portion of the descending colon. One patient had bilateral uretero colonic anastomosis. The operative mortality rate was 7.7%. Determinate 5-year survival rate of 38.5% was achieved. Histological examinations of the surgical specimen revealed associated abscesses adjacent to the tumor in six cases, although the cancer extended to the bowel wall and adhered to the surrounding structures in all specimens. Total pelvic exenteration assures a better quality of life, lessening of symptoms, disease control and, in selected patients, a cure.

Adenocarcinoma↗
PubMed1985

Effects of the lysosomal fraction of polymorphonuclear leukocytes on proliferation of cultured vascular cells.

The effects of the lysosomal fraction isolated from polymorphonuclear leukocytes (PLF) on the growth of cultivated aortic medial smooth muscle cells (SMCs) and arterial endothelial cells (ECs) were studied by assaying DNA synthesis and counting the numbers of cells. PLF proved to promote the growth of cultivated SMCs and ECs. There was a positive correlation between an increase in DNA synthesis and the dose of PLF. The growth-promoting effect was observed in sparsely cultivated SMCs and ECs, in densely cultivated SMCs, but not in confluently cultivated ECs. The difference in response between SMCs and ECs seems to depend on their biological characteristics. Because a small amount of PLF showed potent growth-promoting activity in the presence of 10% fetal bovine serum which possesses a high protease blocking activity, the mechanism of this promoting activity is suggested to be independent of the proteases contained in PLF.

Animals↗
PubMed1985

Production of antibody associated with non-A, non-B hepatitis in a chimpanzee lymphoblastoid cell line established by in vitro transformation with Epstein-Barr virus.

A continuous cell line of chimpanzee lymphocytes producing an antibody specifically associated with non-A, non-B hepatitis (NANB) was established. Peripheral blood lymphocytes of a chimpanzee convalescent from experimental infection with NANB hepatitis were transformed in vitro by Epstein-Barr virus infection into lymphoblastoid cell lines. Supernatants of the cell cultures were screened by immunofluorescence for antibody activity against the liver tissue of a chimpanzee with NANB hepatitis. Nineteen of the 1402 cultures were found to be positive for the activity. Ten of these 19 gave cytoplasmic reactions and the remaining 9 gave nuclear reactions in hepatocytes. One culture (48-1) stably producing the antibody was further characterized. The antibody produced in 48-1 was IgM and gave granular cytoplasmic reactions in hepatocytes. Cloning of 48-1 was performed by the soft agar method and cloned cell lines stably producing the antibody were obtained. The 48-1 antibody reacted with liver biopsy specimens from 12 chimpanzees obtained during the acute or chronic phase of hepatitis caused by five different NANB strains, but not with biopsy specimens from chimpanzees with hepatitis A or B or from normal chimpanzees. In addition, examinations of serial liver biopsy specimens obtained from 2 chimpanzees experimentally infected with NANB hepatitis demonstrated that the antibody reacted with the biopsies obtained during the preacute, acute, and chronic hepatitis, but not with those obtained before inoculation, early incubation period, or during convalescence. The present results indicate the specific association of the antibody with NANB hepatitis. Immunoelectron microscopy revealed that the antibody reacted with the microtubular aggregates identical to those previously described in a patient and chimpanzees with NANB hepatitis.

Animals↗
PubMed1985

5'-Nucleotidase activities in human fetus.

Specific 5'-nucleotidase (5'-N) activity in 17 human fetuses was systemically studied in order to get basic values of the enzyme activity. A wide spectrum of 5'-N activity among the organs was revealed. Very strong activity was found in placenta (42.62 +/- 19.24 nmol adenosine/mg protein/min), skeletal muscle (31.80 +/- 11.10) and skin (27.31 +/- 13.00); strong activity in liver (18.96 +/- 7.60), pituitary (15.06 +/- 6.13) and thyroid (12.69 +/- 4.47); moderate activity in lung (8.43 +/- 3.68), pancreas (8.20 +/- 2.26), small intestine (8.07 +/- 2.28), lymph node (7.26 +/- 2.22), thymus (7.06 +/- 2.52), spinal cord (5.86 +/- 1.96) and spleen (5.65 +/- 2.52), and weak activity in testis (4.02 +/- 0.79), heart (3.95 +/- 1.22), adrenal (3.46 +/- 1.68), kidney (3.16 +/- 0.83), ovary (3.16 +/- 0.72), aorta (2.98 +/- 1.20), cerebellar hemisphere (2.28 +/- 1.09) and frontal lobe of the cerebrum (1.49 +/- 0.54). These data are the first to be reported on specific 5'-N activity in the human fetus. The significance of the wide range of 5'-N activity among the organs, and future aspects on the study of 5'-N activity with respect to cell differentiation, maturation, development, aging or malignant transformation were discussed.

5'-Nucleotidase↗
PubMed1985

A light and electron microscopic study of lamellated nerve endings found in the rat cheek mucosa.

Lamellated nerve endings in the cheek mucosa of fifteen adult Sprague-Dawley rats were studied with light and electron microscopes. Serial sections revealed that the terminal axon of the lamellated nerve endings is in the central portion, and that the inner core is made up of two stacks of lamellae. These are characterized by many corpuscles located within a single papilla, which shows structural specializations at several levels. Electron microscopy showed that the corpuscles are circular in shape and that the lamellar sheets possess a rich rough endoplasmic reticulum, mitochondria and numerous glycogen-like granules. Numerous bundles of collagen fibers and an amorphous substance are located in the interlamellar spaces. The axon terminal is characterized by the presence of neurofilaments, neurotubules and mitochondria. The capsule consists of several laminae formed by cytoplasmic extensions of perineural cells presenting many caveolae, mitochondria, rough endoplasmic reticulum profiles and microfilaments.

Animals↗