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Biomedical subjects

T Taniguchi

Publications and source records attributed to T Taniguchi.

At least 19 recordsLinked to original sources

Unusual location and function of the operator in the Escherichia coli galactose operon.

The operator of the gal operon is located about 60 base pairs preceding the startpoints of the transcription of the two gal promoters. This location contrasts with the location of the operator in other phage or bacterial operons where the repressor binds more closely to the respective transcription initiation sites. Models explaining how the repressor-operator interactions may control the two gal promoters are presented.

Base Sequence

Nasal secretion from normal subjects.

A new method of collection of nasal secretion, by dilution with condensed mositure of the exhaled air, is described. This method may be defined as a sefl-administered nasal lavage. The method permits quantitative determination of pH, relative viscosity, and electrolyte and protein composition. Concentrations of sodium, potassium, calcium, total protein, IgA, IgG, IgM, secretory compoenent and polysaccharide are reported for normal subjects. Significant correlations were noted between the relative viscosity and variables: dry weight, total protein and calcium.

Calcium

Interaction site of Escherichia coli cyclic AMP receptor protein on DNA of galactose operon promoters.

Cyclic AMP (cAMP) and its receptor protein (CRP) have a dual role in the regulation of the two promoters that control the galactose (gal) operon of Escherichia coli. One promoter, P1, requires cAMP-CRP for activity; the other, P2, is inhibited by these factors. We have examined the interactions site of cAMP-CRP on gal DNA by using two types of protection experiments, involving DNase digestion and methylation by dimethyl sulfate. Our results indicate that cAMP-CRP binds to gal DNA in a segment located between 50 and 24 base pairs preceding the P1 start point for transcription. Although the location of the cAMP-CRP interaction site is clearly different in gal and lac DNA, comparison of the DNA sequences suggests a similar recognition sequence. The location of the cAMP . CRP-binding site in gal further suggests that protein-protein interactions between RNA polymerase and cAMP . CRP play an important role in transcription initiation at the gal and possibly other cAMP-dependent promoters.

Base Sequence

Effect of acetylcholine on the norepinephrine-induced positive chronotropy and increase in cyclic nucleotides of isolated rabbit sinoatrial node.

Transmural stimulation of, or application of nicotine to, the isolated rabbit sinoatrial (SA) node resulted in initial negative and late positive chronotropy. Simultaneous application of acetylcholine and norepinephrine produced a similar biphasic chronotropic effect. These procedures produced an initial increase in cyclic guanosine 3':5'-monophosphate (cyclic GMP) and a delayed elevation in cyclic adenosine 3':5'-monophosphate (cyclic AMP). The initial and late effects on rate and nucleotide levels were inhibited by pretreatment with atropine and propranolol, respectively. Pretreatment with atropine shortened the time of maximum increase in cyclic AMP level and heart rate from 3 to 1 minute after the simultaneous application of acetylcholine and norepinephrine and enhanced the positive chronotropic effect. Physostigmine prolonged the duration of the increase in cyclic GMP and negative chronotropic effect after the simultaneous application. These results suggest that when acetylocholine and norepinephrine are present simultaneously in the SA node region, the former interacts predominantly with muscarinic receptors and stimulates the cyclic GMP system, which in effect delays the cyclic AMP elevation and reduces the positive chronotropic effect of norepinephrine. However, these effects of acetylcholine cannot be explained solely on the basis of changes in the cyclic GMP level, because sodium nitroprusside produced a marked elevation of the cyclic GMP levels without decreasing the heart rate and did not affect the norepinephrine-induced increase in pacemaker rate and cyclic AMP. Sodium nitroprusside may affect cyclic GMP pools other than those susceptible to acetylcholine. These cyclic GMP pools may not exert chronotropic effects.

Acetylcholine

Simultaneous surgical treatment of tetralogy of Fallot and coronary artery aneurysm due to mucocutaneous lymph node syndrome in a 4-year-old child.

The simultaneous correction of tetralogy of Fallot and an aneurysm of the coronary artery due to mucocutaneous lymph node syndrome (MCLS) in a 4-year-old boy was successfully performed. Of the four aneurysms found on the coronary angiogram at the age of six months, the smaller three regressed spontaneously leaving slight dilatation and thickening of the arterial wall during the 4-year follow-up period. However, the largest one in the right coronary artery, which remained almost the same size, showed marked stagnation of blood in the aneurysm with the possibility of thrombosis and resultant myocardial infarction. At operation, there was a large aneurysm in the right coronary artery, 9 mm in width and 18 mm in length. The wall of the aneurysm was very thick and tightly adherent to the myocardium. The aneurysm was resected and an aorto-coronary bypass graft was fashioned from a saphenous vein taken from the patient's mother, since an autogenous vein was not available. A ventricular septal defect was closed and pulmonary stenosis was relieved without any difficulty. Postoperative cardiac catheterization and coronary angiography four weeks after the operation revealed satisfactory correction of the tetralogy of Fallot and a patent aorto-coronary vein graft. Several problems regarding surgical treatment of coronary artery aneurysm due to MCLS are discussed.

Adult

Combined effect of BCG and coenzyme Q10 on ATP-ase activity and coenzyme Q content in spleen lymphocytes of tumor-bearing rats.

Effect of BCG, coenzyme Q10, or their combination on ATPase activity in spleen lymphocytes of tumor-bearing rats was investigated in relation to changes in the content of individual coenzyme Q homologs in these cells. Contents of both coenzyme Q9 and Q10 in spleen lymphocytes significantly decreased in the late stage of Donryu rats bearing Sato lung carcinoma. Oligomycin-sensitive ATPase activity in spleen lymphocytes was also significantly depressed in this stage. The depressed, oligomycin-sensitive ATPase activity was significantly recovered by a 3-time intramuscular administration of coenzyme Q10 emulsified with ethanol and saline, and the decreased contents of coenzymes Q9 and Q10 were slightly restored by this treatment. This enzyme activity was also significantly recovered by an intravenous administration of BCG, and was elevated more by the combined treatment with BCG and the emulsified coenzyme Q10. These results suggest that the combined treatment with BCG and emulsified coenzyme Q10 can contribute to the improvement of the depressed bioenergetics in lymphocytes of tumor-bearing animals, and that this combined effect of BCG and emulsified coenzyme Q10 might be based on the combination of their individual activating effect on lymphocytes.

Adenosine Triphosphatases

Effect of cholera enterotoxin on pacemaker rate and cyclic adenosine 3':5'-monophosphate in isolated rabbit sinoatrial node.

The positive chronotropic effect of cholera enterotoxin on isolated rabbit sinoatrial (S-A) node was investigated. This toxin produced a time and dose-related increase in pacemaker rate and cyclic adenosine 3':5'-monophosphate (cyclic AMP) levels and shifted to the left the dose-response curves of norepinephrine on the pacemaker rate and cyclic AMP content in the S-A node. Thus, the sensitivity of the S-A node to norepinephrine was increased by the toxin. These effects of the toxin were not blocked by propranolol. There was a linear relation between the increases in pacemaker rate and cyclic AMP content after application of both the toxin and norepinephrine. However, the slope of the regression line relating pacemaker rate to cyclic AMP level differed with these two agents. These results suggest that cholera enterotoxin increases pacemaker rate with activation of the adenylate cyclase system in the S-A node, but the mechanism differs from that of norepinephrine.

Adenylyl Cyclases