Search PubMed⌕ Search

Biomedical subjects

M Kinjo

Publications and source records attributed to M Kinjo.

At least 73 records · Page 4Linked to original sources
PubMed1989

Species variation in the site and mechanism of the neuromuscular effects of diadonium in rodents.

The unusually wide, 80-fold species variation observed by others (1,2) in the neuromuscular (NM) potency of diadonium, a nondepolarizing muscle relaxant (MR), between cat and man suggested that the site and mechanism of its NM effect may vary in different species. To obtain information on this question, the NM potency of diadonium and the reversibility of its NM effect by neostigmine and/or 4-aminopyridine (4AP) was investigated on the in vitro phrenic nerve--hemidiaphragm preparations of rats, mice and guinea pigs. The concentration of diadonium that caused 90% NM block (IC90) was much greater in guinea pigs, 1.74 +/- 0.02 and 1.28 +/- 0.01 mu, when the preparations were stimulated with single stimuli at 0.1 Hz or with 0.1 s trains of 50 Hz tetani every 10 s, respectively, than in rats (IC90 = 62.4 +/- 0.89 and 52.1 +/- 1.00 microM) or mice (IC90 = 51.9 +/- 0.98 and 44.4 +/- 0.22 microM). In guinea pigs, the NM blocking effect of diadonium could be antagonized by neostigmine. This indicates that in this species the NM blocking effect of diadonium is primarily caused by inhibition of the interaction of acetylcholine (ACh), released by the nerve impulse, with the cholinergic receptors (cholinoceptors) of the postjunctional membrane (p.j.m.). By contrast, in rats and mice diadonium was not antagonized by neostigmine but was reversed by 4-aminopyridine. This suggests that in these species, in contrast to other nondepolarizing MR, diadonium does not inhibit NM transmission postsynaptically, but by inhibiting the positive nicotinic feedback mechanism of mobilization of ACh from reserve depots to release sites, causes a presynaptic NM block.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1988

The intermediate filament system of the keratinizing mouse forestomach epithelium: coexpression of keratins of internal squamous epithelia and of epidermal keratins in differentiating cells.

The internal epithelium of mouse forestomach represents a fully keratinized tissue that has many morphological aspects in common with the integumental epidermis. In the present study we have, therefore, analyzed keratin expression in the total epithelium, in subfractions of basal cells and in living and dead suprabasal cells that were obtained by Percoll density gradient centrifugation of trypsin-dissociated forestomach keratinocytes. The keratin analysis revealed that basal forestomach keratinocytes synthesize the same keratin types as basal epidermal cells (60000, 52,000 and 47,000 daltons), whereas differentiating cells contain both the epidermal suprabasal keratin pair (67,000 and 59,000 daltons) and the suprabasal keratin pair characteristic for other internal squamous epithelia (57,000 and 47,000 daltons). Indirect immunofluorescence using an antibody recognizing the members of the epidermal-type suprabasal keratin pair and in-situ-hybridization experiments using specific cDNA probes for the members of the internal-type keratin pair showed that the two keratin pairs are uniformly coexpressed in living suprabasal forestomach keratinocytes. Furthermore, it could be shown that distinct cells in the basal cell layer acquire the ability to express both the 67,000/59,000 dalton and the 57,000/47,000 dalton keratin pair and that some basal cells apparently lose the ability to synthesize mRNAs for basal keratins.

Animals↗
PubMed1988

Growth and metastasis of Lewis lung carcinoma in the footpad of mice.

When Lewis lung carcinoma cells were transplanted into the footpad of mice, exponential growth of tumour was seen from the 4th day. Intravasation of tumour cells was first seen at this time, then increased steadily up to the 10th day. Tumour cells entered the circulation by destructive degeneration of the vascular endothelium and also by transcellular passage, mainly through capillaries, venules and thin-walled tumour vascular channels. Multiple sites of entry of tumour cells into the circulation were frequently found. The rate of intravasation of tumour cells into the circulation was the same at the proximal, middle and distal portions of the tumour.

Animals↗
PubMed1988

Changes in muscarinic receptors and amylase secretion in regenerating acinar cells of rat pancreas.

Atrophic pancreatic acinar cells of copper-deficient rats recovered after copper supplementation. To clarify whether the recovered cells are regenerative and amylase secretion via muscarinic receptors alters, [3H]-thymidine uptake, [3H]-quinuclidinyl benzilate binding and amylase release were studied in these rats and compared with the values of 5-day-old and 21-week-old rats. The [3H]-thymidine uptake study indicated that the recovered acinar cells were regenerative. The number of muscarinic receptors in regenerating cells was equal to that in mature cells and was one third in cells of 5-day-old rats. The apparent dissociation constant of muscarinic receptors was about 0.73 x 10(-10) M for the regenerating cells, 0.65 x 10(-10) M for 5-day-old rats, and 1.70 x 10(-10) M for 21-week-old rats. Amylase release, as a percent of total amylase, was maintained relatively steady in spite of the low amylase content in regenerating cells. These observations suggest that the affinity of muscarinic receptors increases to compensate the impaired amylase synthesis in regenerating acinar cells and that their amylase secretion via muscarinic receptors is different from that in 5-day-old or mature rats.

Amylases↗
PubMed1988

Fluidity and osmotic sensitivity changes of phospholipase A2-treated liposomes.

Membrane fluidity and osmotic sensitivity were examined in DPPC liposomes treated with phospholipase A2 (PL.A2) in the presence of Ca2+ or Mg2+. The amount of liposome phospholipid hydrolyzed differed with the two ions. Embedded DPH, a rod-like fluorescent probe, was employed in the determination of membrane fluidity. Membrane fluidity decreased according to the degree of phospholipid hydrolization in liposomes by PL.A2. The reciprocal value of absorption at 450 nm was measured as the index of osmotic sensitivity of liposomes. Intact sonicated liposomes showed osmotic insensitivity. PL.A2-treated liposomes in which about 40% of total phospholipid was hydrolyzed showed osmotic sensitivity. No change in the membrane fluidity was obtained when PL.A2-treated liposomes were exposed to hypertonic or hypotonic solution. These results suggested that the motion of the acyl-chain of phospholipids and free fatty acids was resisted in PL.A2-treated liposomes. The resistance may be due to a phase separation between phospholipids and free fatty acids. The pore for water permeation might be induced in the border between phase-separated domains in PL.A2-treated liposomes.

Calcium↗
PubMed1987

alpha-Neoendorphin-like immunoreactivity in medullary carcinoma of the thyroid.

alpha-Neoendorphin-like immunoreactivities (alpha-NE-IR) were demonstrated in tissues from three patients with medullary carcinoma of the thyroid (MCT). A large amount of alpha-NE-IR was detected in the extracts of primary tumors and metastatic lymphatic tissues by a highly sensitive and specific radioimmunoassay (RIA). Gel filtration analyses showed two different molecular-weight forms of the alpha-NE-IR: One eluted at the void fraction and the other at the position of [125I]-alpha-NE on Sephadex (Pharmacia Fine Chemical, Uppsala, Sweden) G-50 chromatography. Immunohistochemical examination revealed the presence of alpha-NE-IR in the C-cell carcinoma. These data presumably reflect that alpha-NE, the opioid peptide derived from preproenkephalin B, is synthesized in the MCT.

Adolescent↗
PubMed1987

Morphological and biochemical changes in the pancreas of copper-deficient rats.

Two types of experimental chronic pancreatic damage were induced in rats by a copper-deficient diet containing D-penicillamine (DP rats) and by a similar diet without D-penicillamine (D rats). At 5-6 weeks after commencement of treatment, serum copper levels showed a significant decrease in both DP rats (1.5 +/- 0.9 micrograms/dl, M +/- SE) and D rats (18.8 +/- 1.4 micrograms/dl) compared with the findings in control rats (111.8 +/- 4.4 micrograms/dl). Histology revealed loss and atrophy of acinar cells in DP rats and mild vacuolar degeneration of acinar cells in D rats, whereas the islets of Langerhans were intact in both groups. The secretion of the exocrine pancreas showed a marked decrease in enzymes and protein output in DP and D rats compared with findings in the control rats. Our study confirmed the relationships between serum copper levels and morphological damage of pancreatic acinar cells or the reduction of enzyme secretion. On the other hand, the reductions in volume and bicarbonate output of pancreatic juice in DP rats and in D rats were detected, but no relationship was found between these reductions and the serum copper levels. The endocrine pancreatic function in DP rats showed a slight disturbance in intravenous glucose tolerance test. These results support the conclusion that copper-deficiency causes disturbances in enzyme-synthesis and selective destruction of acinar cells.

Animals↗
PubMed1987

Coronary atherosclerosis in patients with systemic lupus erythematosus at autopsy.

Using a computed image analyser, coronary arteries from 50 autopsied patients with systemic lupus erythematosus (SLE) were examined on the three vessels (RCA, LAD, LCX) and compared with those of age-matched controls. The intima of coronary artery was significantly thickened much more in the case of SLE than in the case of age-matched controls. This was statistically significant (p less than 0.01). Hypertension and glomerulonephritis did not but corticosteroid therapy had an influence on the development of intimal thickening ratio of the coronary arteries in SLE patients. The mean intimal thickening ratio of the coronary arteries in the patients with SLE and without corticosteroid therapy was larger than that of patients with corticosteroid therapy (p less than 0.1). It appears possible to conclude that inflammatory change of SLE itself is one of the promoting factors of coronary atherosclerosis.

Adolescent↗
PubMed1986

Synthesis of hydrocarbons under presumed prebiotic conditions using high-frequency discharge.

Various hydrocarbons were synthesized by high-frequency discharge in a primordial terrestrial model atmosphere. The products were extracted by benzene or methanol and analyzed by GC-MS. The mean carbon chain length of the hydrocarbons formed by the discharge through pure CH4 gas was less than 6. Benzene was also obtained. Some isomers were obtained for each of the hydrocarbons containing a given number of carbons. When a small amount of C2H2 was added to the CH4, longer chain compounds were formed, as compared with discharge in CH4 only. However, when the amount of C2H2 was increased, unextractable high molecular weight compounds were produced. The amounts of products decreased as the mixing ratio of CO2 to CH4 increased. No hydrocarbons were detected when the ratio of CO2/CH4 exceeded 1.

Acetylene↗
PubMed1986

Enzymatic synthesis and some properties of a model primitive tRNA.

A model primitive tRNA with the nucleotide sequence GGCCAAAAAAAGGCCp was synthesized using T4 RNA ligase. The nucleotide sequence of this newly synthesized oligonucleotide was confirmed by ladder analysis of several enzymatic digestion products. The secondary structure of the oligonucleotide was examined by comparison of the products of its digestion by single- and double-strand-specific nucleases with those of the digestion of the intermediate oligonucleotide GGCCAAAAAAAOH. The results indicated that the two GGCC segments of the 5' and 3' ends of the model tRNA may form base pairs in solution. The same conclusion was derived from the result of affinity-column chromatography of the model oligonucleotide. When 32pGGCCAAAAAAAGGCCOH was passed through a poly(U)-agarose column, about 70% of the applied sample bound to the poly(U)-agarose. In contrast, when the model oligonucleotide was passed through a poly(C)-agarose column, only 15% of the sample bound to the poly(C)-agarose. These results indicate that the newly synthesized oligonucleotide adopts a hairpin structure in solution. Two aspects of a potential biological activity of the synthetic model tRNA were examined. It was found that the oligonucleotide can bind to poly(U)-programmed 30S ribosomes and is recognized by Q beta replicase as a template for RNA synthesis.

Base Sequence↗
PubMed1986

Leiomyosarcoma of the spermatic cord. A case report and a brief review of literature.

A case of leiomyosarcoma of the spermatic cord, occurring in a 79-year-old male patient, is reported. The tumor was resected with high inguinal ligation and orchiectomy. It was located at the scrotal part of the spermatic cord on the left side and was shown to have originated from the spermatic duct using the dissecting method. Histologically, it was identical to leiomyosarcoma showing a typical morphological appearance of smooth muscle cell tumor in the conventional histochemical preparations as well as a focal positive reaction to antidesmin antibody, a marked nuclear pleomorphism, and abundant mitotic figures. The patient had been untroubled for six months after the resection of the tumor. Leiomyosarcoma arising in spermatic cord is quite rare.

Aged↗
PubMed1985

Incidence and significance of intrarenal vasculopathies in patients with systemic lupus erythematosus.

A clinicopathologic autopsy study of the vascular changes in the kidneys of 100 patients with systemic lupus erythematosus was undertaken. Necrotizing arteritis was found in seven patients, mucinous intimal thickening in nine, onion-skin intimal thickening in two, and renal vein thrombosis in two. Active necrotizing arteritis was present most frequently in the arterioles and interlobular arteries, with healing necrotizing arteritis predominating in the arcuate and interlobar arteries. These events were closely related to the activity of glomerular lesions, and immunologic vascular injury seemed to be the causative factor. Rapidly progressive renal failure and severe hypertension had characterized the clinical courses of the patients. Mucinous intimal thickening, present in the arterioles and interlobular arteries, had been accompanied by accelerated hypertension. Although dialysis or accelerated hypertension may have been causes, other factors, including glucocorticoid therapy, must be considered. In one patient with class II lupus nephritis, renal vein thrombosis was considered the cause of the nephrotic syndrome. These vasculopathies, often detected in patients with lupus at autopsy, seem to alter the clinical course.

Adolescent↗