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Biomedical subjects

A Takagi

Publications and source records attributed to A Takagi.

At least 289 records · Page 16Linked to original sources
PubMed1984

Hydrogen ion diffusion in dog gastric mucus glycoprotein: effect of associated lipids and covalently bound fatty acids.

The effect of neutral lipids, glycolipids and phospholipids associated with dog gastric mucus glycoprotein, and that of covalently bound fatty acids on the ability of glycoprotein to retard the diffusion of hydrogen ion was investigated. Purified mucus glycoprotein in its native form, placed between equimolar (0.155M) solutions of HCl and NaCl in a specially designed two-compartment chamber, caused a 90% reduction in permeability to hydrogen ion when compared with a layer of NaCl. Extraction of associated lipids lead to a 68% increase in permeability of the glycoprotein to hydrogen ion, while removal of the covalently bound fatty acids increased further the diffusion rate by 6%. Reassociation of the delipidated glycoprotein with its neutral lipids reduced the permeability to hydrogen ion by 34%, an 11% reduction was obtained with glycolipids, and 23% with phospholipids. Since neutral lipids account for 47% of the glycoprotein lipids, glycolipids 41.1% and phospholipids 11.9%, the quantitative decrease in permeability of the delipidated glycoprotein following its reassociation with phospholipids is 2.7 times greater than that of neutral lipids and 7.3 times greater than that of glycolipids.

Animals↗
PubMed1984

Cell growth and differentiation in vitro in mouse macrophages transformed by a tsA mutant of simian virus 40. II. Changes in the distribution of DNA content during the reversible transition between macrophage and nonmacrophage states in the cultures of tsA640-transformed macrophages.

Cultures of mouse macrophage cell lines transformed by wild-type or the tsA640 mutant of simian virus 40 (SV40) show a reversible phenotypic transition between the nonmacrophage (proliferating phase) and the macrophage (stationary phase) states (Takayama, 1980; Tanigawa et al., 1983). Distribution of DNA content in the cultures of the tsA640-transformed macrophage lines in the process of the phenotypic transition was determined by flow cytometry. Taking the mean DNA content of mouse peritoneal macrophages as 1 unit in the scale of fluorescence intensity in the flow cytogram, the transformed macrophages showed, at 33 degrees C, two peaks, one located around the 1.0-unit position (peak 1.0) and the other around the 1.6-unit position (peak 1.6), and a plateau distribution continuing to 3.2 units. Peak 1.0 was predominant in the stationary-phase culture, whereas peak 1.6 was predominant in the proliferating-phase culture. Almost the entire population of the strictly resting culture, which was obtained by culturing the stationary-phase culture for a further 5 days at nonpermissive temperature (39 degrees C), was phagocytic, and had accumulated at peak 1.0. Cells in peak 1.0 moved to peak 1.6 and to higher positions, after the strictly resting culture was sparsely reseeded and incubated at 33 degrees C. In contrast, the DNA content distribution of the successively proliferating cells, which were obtained by repeated passage of an extensively proliferating culture and none of which were phagocytic, was similar to that of proliferating hypotetraploid BALB/c3T3 fibroblasts with a G1 peak at 1.6 unit followed by a plateau containing S- and G2-phase cells. The peak 1.0 cell population appeared from the recloned population of the successively proliferating cells in company with the restoration of the culture condition-dependent phagocytic ability when cocultured with primary macrophages. Each peak in the flow cytogram reflected fairly well DNA content per cell as determined by other methods.

Animals↗
PubMed1984

The role of covalently bound fatty acids in the degradation of human gastric mucus glycoprotein.

The undegraded high-molecular-weight glycoprotein of human gastric mucus has been isolated free of noncovalently bound proteins and lipids, as judged by gel filtration, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, cesium chloride density gradient centrifugation, and lipid analysis. Mild alkaline methanolysis of the thoroughly delipidated glycoprotein revealed that, on the average, the native undegraded glycoprotein contains 2.9 mol of acyl linked fatty acids/mg glycoprotein. The low-molecular-weight glycoprotein subunits, obtained after pepsin digestion, contain 2 nmol of acyl linked fatty acids/mg glycopeptide. The highest content of covalently bound fatty acids was found in the fraction of glycoprotein which remained undegraded after pepsin digestion. On the average, 10.2 mol of fatty acids/mg was substituted on this pepsin-resistant glycoprotein. After deacylation with hydroxylamine, the undegraded pepsin-resistant glycoprotein became susceptible to proteolytic cleavage. The obtained results suggest that fatty acids covalently bound to gastric mucus glycoprotein are involved in the regulation of proteolytic digestion of mucus glycoprotein in the stomach.

Chemical Phenomena↗
PubMed1984

Muscular abnormalities in experimental hypothyroidism of rats with special reference to the mounding phenomenon.

The mounding phenomenon was examined in vitro on the excised extensor digitorum longus or soleus muscle of hypothyroid rats. The mounding phenomenon was more prominent and lasted longer in hypothyroid muscles than in controls. In single skinned muscle fibers of both type 1 and type 2 from hypothyroid animals, the maximum tension produced by Ca ion was reduced and activity of Ca uptake by the sarcoplasmic reticulum was also decreased, judging from the response to caffeine. Decreased Ca uptake might retard the relaxation of contracture, thereby rendering the mounding more prominent. Morphological studies of both extensor digitorum longus and soleus muscles showed an increase of type 1 muscle fiber population as well as mild changes in arrangement of the internal membrane system. However, there was no muscle necrosis or other derangements. These results supported the idea that functional abnormality of the sarcoplasmic reticulum could be the basis of the exaggeration of the mounding phenomenon in hypothyroidism.

Animals↗
PubMed1984

Transformation of protoplasted yeast cells is directly associated with cell fusion.

The frequency of cell fusion during transformation of yeast protoplasts with various yeast plasmids with a chromosome replicon (YRp or YCp) or 2 mu DNA (YEp) was estimated by two methods. In one method, a mixture of protoplasts of two haploid strains with identical mating type and complementary auxotrophic nuclear markers with or without cytoplasmic markers was transformed. When the number of various phenotypic classes of transformants for the nuclear markers was analyzed by equations derived from binominal distribution theory, the frequency of nuclear fusion among the transformants was 42 to 100% in transformations with the YRp or YCp plasmids and 28 to 39% with the YEp plasmids. In another method, a haploid bearing the sir mutation, which allows a diploid (or polyploid) homozygous for the MAT (mating type) locus to sporulate by the expression of the silent mating-type loci HML and HMR, was transformed with the plasmids. Sporulation ability was found in 43 to 95% of the transformants with the YRp or YCp plasmids, and 26 to 31% of the YEp transformants. When cytoplasmic mixing was included with the nuclear fusion, 96 to 100% of the transformants were found to be cell fusants. Based upon these observations, we concluded that transformation of yeast protoplasts is directly associated with cell fusion.

Cell Fusion↗
PubMed1984

Idiopathic hyperCKemia.

In three adult men, serum creatine kinase activity was constantly raised for at least 4 years. They had been normal in other neuromuscular functions and did not have any established disease. Quantitative morphologic and pharmacologic studies were performed on biopsied muscle. The biceps brachii of patient 1 contained 0.3% necrotic fibers. In patient 2, only slight variation of muscle fiber diameter was noted. Muscle of patient 3 contained a few small angular fibers, and 11% of fibers exhibited internal nuclei. Sensitivity to caffeine in vitro was increased in patients 2 and 3, as seen in survivors of malignant hyperthermia; patients in hyperCKemia may be susceptible to malignant hyperthermia.

Adult↗
PubMed1984

[Renovascular hypertension with a solitary kidney associated with retrocaval ureter: a case report].

A case of renovascular hypertension in a patient with a congenitally solitary kidney associated with retrocaval ureter is reported. Aortorenal bypass with autogenous saphenous vein graft and concomitant mobilization of the ureter by division and reanastomosis of the inferior vena cava were performed. Pathogenesis of the stenotic lesion of the renal artery was fibromuscular dysplasia. Postoperative improvement of hypertension was not so good as expected. Soon after administration of nifedipine (20mg/day) was started, blood pressure decreased down to 130/80mmHg and had been well controlled. Problems regarding renovascular hypertension with a solitary kidney and surgical treatment of retrocaval ureter are discussed.

Adult↗
PubMed1984

[Isolated iliac aneurysms].

An isolated iliac aneurysm is an uncommon entity with a relative incidence to abdominal aortic aneurysm of 0.9 to 1.9 percent. Analysis of 16 cases with 20 isolated iliac aneurysms experienced at our vascular service makes the basis of this report. Seventeen aneurysms involved the common iliac artery, two the internal iliac artery and one the external iliac artery. As we experienced 341 abdominal aortic aneurysms during the same period, relative incidence of isolated iliac aneurysm to abdominal aortic aneurysm was 4.7 percent. Fifteen of the 16 cases were male; isolated iliac aneurysms had significantly higher preponderance for the male. Six of the cases were presented with ruptured aneurysms, giving a rupture rate of 37.5 percent. This rupture rate was significantly higher than that of abdominal aortic aneurysms of 11.1 percent. Operation was performed on 15 patients; the remaining one died before surgery. Although there was no operative death among the elective cases, three patients in the ruptured group died postoperatively giving a mortality rate of 60 percent. The least diameter of the ruptured aneurysms was 3.5 centimeter. Among the 16 patients 5 presented with a ruptured aneurysm and 3 had no symptoms related to the aneurysm. Five patients complained of a pulsatile abdominal mass. Two of the ruptured aneurysms were associated with an iliac arteriovenous fistula. Both of them involved the common iliac artery. Although emergency operation was performed on one of them, he died of acute renal failure due to preoperative dehydration and hypovolemia. The another one was operated on electively after intensive medical treatment for heart failure and the patient survived.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Studies on peptides. CXIII. Synthesis of the heptacosapeptide amide corresponding to the entire amino acid sequence of chicken secretin.

The heptacosapeptide amide corresponding to the entire amino acid sequence of chicken secretin was synthesized by assembling four peptide fragments followed by deprotection with thioanisole-mediated trifluoromethanesulfonic acid in TFA. The deprotected peptide was purified by gel-filtration on Sephadex G-25, followed by ion-exchange chromatographies on CM-cellulose and DEAE-Sepharose. Synthetic peptide stimulated the flow of pancreatic alkaline juice and decreased systemic blood pressure in rats.

Amino Acid Sequence↗
PubMed1983

Cell growth and differentiation in vitro in mouse macrophages transformed by a tsA mutant of simian virus 40. I. Cellular response in proliferative and phagocytic activities to the shift of temperature differs depending on the culture state in mouse bone marrow cells transformed by the tsA640 mutant of simian virus 40.

It was shown previously that mouse bone marrow cells transformed by simian virus 40 (SV40) show a reversible cell density-dependent phenotypic transition between the nonmacrophage (rapidly growing) and the macrophage (stationary) states; cells in low-density cultures are in the growing phase, express SV40 T antigen strongly as revealed by immunofluorescence, and lose typical macrophage properties such as immune phagocytosis; whereas cells in high-density cultures are in the stationary (nongrowing) phase, express SV40 T antigen weakly, and recover their macrophage properties (Takayama, 1980). In the hope of clarifying the relationship between T antigen, cell growth, and macrophage-specific cellular function, we examined the behavior at 33 and 39 degrees C of mouse bone marrow cells transformed by an SV40 gene A mutant (tsA640) whose mutation renders the molecular weight of 90K (large) T antigen temperature sensitive. The results presented in this paper suggest that functional large T antigen is required for cells in the stationary phase to initiate multiplication when transferred at lower density and is not necessary for a majority of them to maintain the nongrowing state (viability) at both high and lower cell densities, whereas it is required for cells in the growing phase to keep multiplying without losing their viability. The results also suggest that the functional large T antigen does not play a direct role in maintaining the cells as either phagocytic or nonphagocytic. It is also suggested that the physiological or tsA mutation-mediated arrest of growth may or may not be accompanied by induction and/or maintenance of cellular phagocytic activity depending on the culture state.

Animals↗
PubMed1983

Malignant hyperthermia and related neuromuscular diseases: caffeine contracture of the skinned muscle fibers.

Using the skinned fiber preparation, the response to caffeine was studied on the skeletal muscle of malignant hyperthermia or other neuromuscular diseases. The sensitivity to caffeine was increased in the muscle of malignant hyperthermia. The sensitivity also was increased in Duchenne muscular dystrophy or asymptomatic patients with raised serum creatine kinase activity. Judging from the interaction between caffeine and the contractile system, the abnormal response originated from the sarcoplasmic reticulum in malignant hyperthermia. In Duchenne muscular dystrophy, the contractile system also might be involved in the increased sensitivity. Since the disease spectrum presenting abnormal responses is broad, it is suggested that muscle fibers become sensitive to caffeine when they are degenerating or regenerating.

Adolescent↗
PubMed1983

Pathophysiology of muscle fiber necrosis induced by bupivacaine hydrochloride (Marcaine).

A single direct injection of a local anesthetic, 0.5% bupivacaine hydrochloride (BPVC) (Marcaine), into rat soleus and extensor digitorum longus (EDL) muscles produced massive fiber necrosis with extensive phagocytosis followed by rapid regeneration, predominantly in the soleus. Since the sarcoplasmic reticulum (SR) was functionally disturbed by BPVC administration as confirmed by an in vitro study, the sarcolemmal lysis seen in the early phase of degeneration was not assumed to simply result from direct damage to the plasma membrane caused by BPVC. The extracellular fluid containing a high concentration of calcium (Ca) ions then permeated into the sarcoplasm through the defective membrane resulting in hyper-contracted myofibrils. Selective damage to the Z-line, an early sign of muscle degeneration, was shown by electron microscopy and SDS gel electrophoresis (preferential loss of alpha-actinin). Administration of leupeptin, a thiol protease inhibitor, proved to be ineffective in inhibiting the necrotic process, because the BPVC induced muscle fiber breakdown was probably too acute and fulminant to demonstrate the inhibitory effect upon the degenerative process. Well preserved satellite cells, peripheral nerves, and acetylcholinesterase activity, and the absence of fibrous tissue proliferation in this system may be responsible for the extremely rapid regeneration with complete muscle fiber type differentiation. Since the sequence of fiber breakdown induced by BPVC administration was similar to that of progressive muscular dystrophy, this chemical will be one of the most useful tools for studying the pathophysiology of fiber necrosis and regeneration in diseased muscle.

Animals↗