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Biomedical subjects

Y Takagi

Publications and source records attributed to Y Takagi.

At least 721 records · Page 40Linked to original sources

Clinical studies on human pancreatic deoxyribonuclease I.

Duodenal juice collected after administration of Boot's pancreozymin and secretin to patients with various pancreatic diseases was subjected to deoxyribonuclease I (DNase I) assay, as well as measurements of total volume, amylase output and maximum bicarbonate concentration. It was observed that the DNase I output is well correlated with each of three factors. The DNase I output was much lower in patients with chronic pancreatitis or pancreatic cancer than in control subjects, and DNase I output was even found to be low in patients suspected of having chronic pancreatitis, who did not give abnormal resulsts with other assay methods. These results imply that DNase I output may be a good indicator of exocrine function of the pancreas, and thus may be useful for early detection of pancreatic diseases.

Amylases↗

Packaging of ColE1 DNA having a lambda phage cohesive end site.

The mechanism of lambda phage-mediated transduction of hybrid colicin E1 DNAs of various lengths was studied, and factors influencing the formation of these transducing particles were investigated. The results were as follows: 1. The presence of a cohesive end site of lambda phage (coslambda) on colicin E1 DNA was essential for packaging of the DNA. 2. Packaging of colicin E1 DNAs, which carry coslambda with molecular sizes corresponding to 68% of that of lambda phage DNA, was observed in the absence of all known recombination functions of E. coli K-12 and of lambda phage. 3. Hybrid colicin E1 DNAs having coslambda with molecular sizes corresponding to 28% of that of lambda phage DNA were packaged within lambda phage particles as trimers; hybrid DNAs with coslambda of 40 and 47% of the length of lambda phage DNA were packaged as dimers; and those with molecular sizes of 68% of that of lambda phage DNA were packaged mostly as monomers. These results demonstrated that two factors are essential for the packaging of DNAs within lambda phage particles; the presence of coslambda on the DNA molecule and an appropriate size of DNA.

Bacteriocin Plasmids↗

Precocious differentiation of mouse parotid glands and pancreas induced by hormones.

Changes of alpha-amylase activity (1,4-alpha-D-glucan glucanohydrolase, EC 3.2.1.1) in mouse parotid gland and pancreas were investigated during embryonic and postnatal development. Amylase activity in the parotid gland increased from around day 12 and reached the adult level on day 30. On the other hand, the activity in the pancreas increased during the last stage of gestation, decreased after birth, and then gradually increased from around day 15, reaching the adult level on day 35. Precocious differentiation of the parotid gland was induced by injections of hydrocortisone or thyroxine after birth, but these hormones did not have additive effects on the parotid gland. Injection of insulin had little effect when given alone, but suppressed the effects of the other two hormones on the gland. Only hydrocortisone increased the amylase activity in mouse pancreas during postnatal development, the other two hormones causing slight decrease in pancreatic amylase. Adrenalectomy and injection of hydrocortisone affected the parotid gland but not the pancreas of adult mice. These results suggest that hydrocortisone is involved in cytodifferentiations of the parotid gland and pancreas, and in maintenance of the parotid gland. Thyroxine may also be important in differentiation of the parotid gland.

Adrenalectomy↗

Colicinogenic mutant of ColE1 plasmid that fails to confer immunity to colicin E1.

Insertion of the ampicillin transposon (Tn3) into ColE1 DNAs causes various mutations in the plasmids. Escherichia coli K-12 cells carrying one of these mutants showed novel properties; they were sensitive to colicin E1 and were able to produce active colicin E1. The site and the orientation of Tn3 insertion in this mutant ColE1 DNA were determined by heteroduplex analysis and by enzymatic digestion with restriction endonucleases. The potential usefulness of this mutant ColE1 DNA as a cloning vehicle is discussed.

Ampicillin↗

Purification and the ultrastructure of a bacteriocin produced from Shigella sonnei strain 100052.

A bacteriocin produced by strain 100052 of Shigella sonnei (shigellacin 52) was purified about 80-fold from a mitomycin C-induced culture supernatant. The purified preparation gave a single band on sodium dodecyl sulfate-gel electrophoresis with an approximate molecular weight of 10,000. The negatively stained electron micrograph of the purified bacteriocin preparation revealed the existence of three different particles. They were a small cylindrical tube (4.2 by 6.0 nm), a ring-shaped particle and a filamentous structure. The molecular weight calculated from the shape of the small tube was approximately 50,000. The latter two particles appeared to be constructed from subunits which were morphologically similar to the cylindrical tube. These results suggested that the morphological subunit of shigellacin 52 consisted of five chemical subunits with molecular weights of 10,000 each, and it assembled into two types of polymers, a ring-shaped particle and a filamentous structure, which seemed to be the main components of the purified shigellacin 52 preparation.

Bacteriocins↗

Isolation and characterization of a plaque-forming lambda bacteriophage carrying a ColE1 plasmid.

A plaque-forming lambdaimm434 bacteriophage carrying the entire genome of colicinogenic factor E1 has been isolated and characterized. This phage, lambdaimm434ColE1, can lysogenize as a stable plasmid within a recombination-deficient Escherichia coli cell that lacks the normal attachment site for lambda phage. Furthermore, it has been found that lambdaimm434ColE1 phage carrying amber mutations in the O and P genes of the lambda genome, i.e., lambdaimm434OamPamColE1, behaves as a plaque-forming phage, and this finding suggests that the ColE1 factor DNA permits replication of the DNA of the plaque-forming phage.

Bacteriocin Plasmids↗

Ultrasonic features of anomalous origin of the left coronary artery from the pulmonary artery.

Two cases of anomalous origin of the left coronary artery from the pulmonary artery with and without marked dilatation of the right coronary artery were studied by M-mode echocardiography and cross-sectional echocardiography. The M-mode echocardiogram obtained from the case with the dilated right coronary artery demonstrated an abnormal structure anterior to the aortic root. The cross-sectional echocardiogram of the same case visualized the origin of the dilated right coronary artery. In addition, echocardiographic abnormalities suggesting the ischemia of the left ventricle were observed in both cases. Although many of the ultrasonic features are nonspecific, the combination of ultrasonic technique provides useful clues to the diagnosis of anomalous origin of the left coronary artery from the pulmonary artery.

Adult↗

Echocardiographic features of congenital pulmonary regurgitation.

Eight patients with congenital pulmonary regurgitation documented by cardiac catheterization and angiography were studied by echocardiography. Echocardiographic features of the pulmonary valve observed in this condition included a) diastolic fluttering (5 cases), b) diastolic separation (2 cases), and c) increase of posterior motion during atrial systole (a wave). Maximum a wave depth exceeded the upper limit of the normal value in 2 cases and averaged 6.1 +/- 0.7 (standard error of the mean) mm. In addition, d) diastolic fluttering of the anterior tricuspid valve was seen in 5 cases and e) abnormal interventricular septal motion in 2 cases (one, paradoxical and the other, flat). Of these findings, the diastolic fluttering of the pulmonary valve, which results from the turbulent stream of blood in the outflow of the right ventricle striking the pulmonary valve, is pathognomonic for pulmonary regurgitation. Although the other findings are nonspecific, all patients had at least 1 of these 5 findings. Echocardiography, therefore, provides useful clues to the diagnosis of pulmonary regurgitation. Furthermore, echocardiography should be of use in differentiating congenital from functional pulmonary regurgitation and from aortic regurgitation.

Adolescent↗