Search PubMed⌕ Search

Biomedical subjects

H Adachi

Publications and source records attributed to H Adachi.

At least 433 records · Page 24Linked to original sources
PubMed1987

A water-soluble form of penicillin-binding protein 2 of Escherichia coli constructed by site-directed mutagenesis.

Penicillin-binding protein (PBP) 2 of Escherichia coli is located in the cytoplasmic membrane. The N-terminal hydrophobic segment (31 amino acids, residues 15-45) of PBP2 was removed by a deletion in the PBP2 gene by site-directed mutagenesis, resulting in the production of a water-soluble form of PBP2 (called PBP2*). PBP2* retained the penicillin-binding activity, was localized in the cytoplasm and was overproduced under the control of the lpp-lac promoter. this indicates that the removed hydrophobic segment is an uncleaved signal sequence required for translocation of PBP2 across the cytoplasmic membrane, and also suggests that the segment anchors the protein to the membrane.

Bacterial Proteins↗
PubMed1987

Synthesis and degradation of H1 histone subtypes in mouse lymphoma L5178Y cells.

H1 histone of mouse lymphoma L5178Y was fractionated into five subtypes, I-V, by Bio-Rex 70 column chromatography. The rates of synthesis of subtypes III and V were higher than those of I, II, and IV, as determined by the measurement of [3H]lysine incorporation. The degradation of the subtype was estimated assuming first order kinetics; subtypes III and V had half-lives of 18 h and 25 h, respectively, and the three other subtypes all had half-lives of 63 h. The syntheses of these subtypes during the cell cycle were examined using synchronized cultures. The syntheses of subtypes I, II, and IV started at the beginning of S phase, whereas those of III and V started in mid-S phase. The syntheses of III and V were at least 1.5-2 times more rapid than those of I, II, and IV, and their active synthesis was accompanied by their rapid degradation. The five subtypes of H1 were further characterized in relation to phosphorylation. Each showed characteristic differences in its synthetic pattern or phosphorylation, and we concluded that each H1 subtype has its own specific function at least in the process of replication of chromatin.

Animals↗
PubMed1987

Identification of the active site of Citrobacter freundii beta-lactamase using dansyl-penicillin.

The active site sequence of a beta-lactamase encoded by chromosomal gene(s) in Citrobacter freundii GN346 was determined using dansyl-penicillin as a fluorescent probe. The tryptic digest of the labelled enzyme gave a fluorescent peptide containing 22 amino acids. The sequence of this peptide was identical to the consensus sequence of class C beta-lactamases, Gly-Ser-X-Ser-Lys. The residue labelled was the serine adjacent to the glycine. The active site sequence corresponded to positions 46-67 of the entire sequence of the Citrobacter freundii beta-lactamase determined on the basis of the DNA sequence of the structural gene [(1986) Eur. J. Biochem. 156, 441-445]. The labelled serine corresponded to Ser-64.

Amino Acid Sequence↗
PubMed1987

Assessment of myocardial blood flow by real-time infrared imaging.

In order to evaluate the applicability of infrared imaging for the assessment of myocardial perfusion, 10 open-chested dogs were studied by a real-time infrared imaging system. The left anterior descending coronary artery was occluded for 90 min followed by 210 min of reperfusion. During the experiment, myocardial surface temperature was mapped by an infrared imaging system with a thermal resolution power of 0.1 degree C and correlated with regional myocardial blood flow measured using radiolabeled microspheres. Following the experiment, acute myocardial injury was evaluated using triphenyltetrazolium chloride staining. After 90 min of ischemia, there was a significant correlation between myocardial blood flow and myocardial surface temperature (R = 0.694, P less than 0.001). After reperfusion, temperature did not correlate with blood flow, but there was a significant correlation between temperature and ischemic myocardial injury (R = 0.551, P less than 0.05). Temperature changes during acute regional ischemia and reperfusion may be regulated by the changes in myocardial blood flow and myocardial metabolism. Temperature analysis using real-time infrared imaging may be a useful means for the evaluation of myocardial blood flow and myocardial injury during ischemia and reperfusion.

Animals↗
PubMed1987

Usefulness of selective arterial secretin injection test for localization of gastrinoma in the Zollinger-Ellison syndrome.

Secretin was injected into a feeding or nonfeeding artery of a gastrinoma and blood samples were taken from the hepatic vein (HV) or a peripheral artery (PA) to measure the changes of serum immunoreactive gastrin concentration (IRG). The IRG in the HV rose within 40 seconds and in the PA rose within 60 seconds after the injection of secretin into a feeding artery, but not after secretin was injected into a nonfeeder. These results indicated that secretin directly stimulates a gastrinoma to release gastrin in vivo. The selective arterial secretin injection test (SASI test) was applied in three patients in whom gastrinomas could not be located by computed tomography, ultrasonography, or arteriography, and functioning gastrinomas were located in all three patients. In one patient, malignant gastrinomas in the head of the pancreas and in the duodenum could be resected radically with the help of this test.

Adult↗
PubMed1987

High alkaline phosphatase activity of telangiectatic osteosarcoma (TOS) and its diagnostic significance.

Telangiectatic osteosarcoma (TOS) which occurred in the metaphysis of the right femoral bone in a 13-year-old female was reported. It showed osteolytic and cystic lesion without sclerotic change on roentgenogram and consisted histologically of various sized blood-filled spaces lined by layers of round to oval tumor cells in the thin fibrous septa. In some solid areas, a proliferation of atypical tumor cells with large prominent nucleoli was evident, embedded in the lace-like osteoid tissue. Mitotic cells were easily encountered. A large population of tumor cells revealed high alkaline phosphatase activity as well as 5'-nucleotidase activity, indicative of osteogenic cell origin. Ultrastructurally, they showed osteogenic characteristics of well-developed rough endoplasmic reticula, cytoplasmic microfibrils, and dense bodies, but not for those of endothelial cells. In this report, we suggest that alkaline phosphatase activity in biopsy and surgical specimens is useful for distinguishing TOS from other osteolytic bone tumors, with regard to its ontogenic discussion.

Adolescent↗
PubMed1987

Carbachol regulates cholecystokinin receptor on pancreatic acinar cells.

We have examined the effect of carbamylcholine on the binding of cholecystokinin (CCK) to dispersed acini from rat pancreas. The CCK receptor on pancreatic acini possesses two classes of binding sites. Simultaneous addition of carbamylcholine inhibited binding of CCK to acini due to an apparent loss of high affinity CCK binding sites. Atropine prevented the inhibitory effect of carbamylcholine, whereas calcium ionophore A23187 did not alter binding of CCK. 12-O-tetradecanoylphorbol-13-acetate (TPA) inhibited binding of CCK in the same manner as carbamylcholine. Inhibition by carbamylcholine was reversible and the recovery was time dependent. By contrast, inhibition of binding of CCK by TPA did not reverse after a 60-min incubation without the agent. These findings, at least in part, account for the inhibition of the CCK-induced stimulation of amylase secretion by carbamylcholine. The action of TPA on binding of CCK suggests the possible involvement of the activation of protein kinase C in the inhibition of binding.

Animals↗
PubMed1987

Cholecystokinin-stimulated pepsinogen secretion and cholecystokinin receptors on gastric chief cells in guinea pigs.

We investigated cholecystokinin (CCK) receptors on isolated gastric chief cells from guinea pig. CCK stimulated pepsinogen secretion from chief cells at the same efficacy as that induced by carbamylcholine. Binding of 125I-labeled CCK-33 (125I-CCK) to chief cells was temperature-dependent, and was saturable and reversible at 37 degrees C. Hofstee plots of the ability of CCK-8 to inhibit binding of 125I-CCK showed a linear regression line, suggesting that CCK receptors possessed one binding site. The dissociation constant of the binding site was calculated to be 3.8 x 10(-10) M. The dose-response curve of CCK for pepsinogen secretion was superimposed on that for the binding to its receptors. These results indicated that gastric chief cells from the guinea pig possess CCK receptors that relate closely to the action of CCK involved in pepsinogen secretion.

Animals↗
PubMed1987

[One-year chronic dietary toxicity study of d.d-T80-prallethrin in rats].

d.d-T80-prallethrin, a pyrethroid insecticide for sanitary use, was administered to Crj : CD (Sprague Dawley) rats at concentrations of 120, 600 or 3,000 ppm in diet for one year to assess the chronic toxicity potential and the reversibility. The summarized results obtained are as follows: 1. Chronic toxicity study 3,000 ppm : Decreases in body weight gain, food consumption, and water intake were observed. Slight alopecia in the neck and/or back was noticed during the first and second weeks, but the animals were recovered thereafter. Slight anemic changes such as decreases in hemoglobin concentration, hematocrit value, MCV and MCH were observed in the females at 52 week. Blood biochemistry revealed increases in total cholesterol (in the males and females at 13, 26 and 52 weeks), phospholipid (in the males and females at 13, 26 and 52 weeks), albumin (in the males at 13 and 26 weeks, in the females at 52 week), total protein (in the males at 26 week, in the females at 52 week), A/G ratio (in the males at 13 week, in the females at 26 week), creatinine (in the males at 52 week), urea nitrogen (in the females at 52 week), GOT (in the males and females at 52 week) and GPT (in the males and females at 52 week), and decreases in triglyceride (in the females at 26 and 52 weeks) and alkaline phosphatase (in the males at 13 and 52 weeks). In urinalysis, an increase in bilirubin was observed in the males at 52 week. Gross-pathology revealed a lower incidence of accentuated lobular pattern of liver (in the males at 26 week) and a higher incidence of enlarged liver (in the males at 52 week). In organ weight, increases in liver (in the males and females at 26 and 52 weeks), kidney (in the males at 26 and 52 weeks) and thyroid weights (in the males at 26 and 52 weeks, in the females at 26 week), and decreases in spleen (in the females at 26 and 52 weeks) and adrenal weights (in the females at 52 week) were observed. Histopathological examination revealed a lower incidence of fatty metamorphosis in the liver of females at 52 week. 600 ppm: An increase in liver weight was observed in the males at 26 week. 120 ppm: No effect was observed. 2. Reversibility study Almost all the above chronic toxicities were reversible.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

[Effects of acid-base balance and Apgar score on fibrinopeptide A and fibrinopeptide B beta 15-42 in umbilical cord blood].

Previous studies on asphyxia neonatorum show that the infant's blood is in a state of hypercoagulability at such a time. In the present study, we determined the amount of fibrinopeptide A (FPA) and fibrinopeptide B beta 15-42 (FPB beta), new sensitive indicators of the coagulation-fibrinolytic system, in the newborn, and examined their relationship to the acid-base balance in umbilical artery blood in elective cesarean section and vaginal delivery, as well as to the Apgar score (Ap. S). In addition, the findings in umbilical cord blood were then compared with those in the blood of normal adults. The results were as follows: In vaginal delivery, infants with Ap. S at 5-7, pH, had significantly lower HCO-3 and BE readings lower while PCO2 was significantly increased, which indicated respiratory and metabolic acidosis. In the vaginal delivery group, FPA was significantly increased in infants with pH under 7.24, PCO2 over 50 mmHg, BE under -8 and Ap. S at 5-7, and as well as in infants in the elective cesarean section group with Ap. S at 5-7. This suggests that the production of thrombin is accelerated if the fetus is asphyxiated. FPB beta was not significantly different among groups. However, FPB beta was significantly higher in various vaginal delivery groups than in the elective cesarean section group (Ap. S greater than or equal to 8), which implies acceleration of the production of plasmin and fibrinolysis in vaginal delivery. FPA and FPB beta were markedly increased in umbilical cord blood as compared with the blood of normal adults. This suggests that blood coagulation and fibrinolysis were accelerated in umbilical cord blood.

Acid-Base Equilibrium↗
PubMed1987

Effects of verapamil and nitroglycerin on coronary and systemic hemodynamics in conscious dogs.

Effects of i.v. bolus administration of verapamil (10-300 micrograms/kg) and nitroglycerin (0.01-30 micrograms/kg) on coronary and systemic hemodynamics were studied in chronically instrumented conscious dogs. Verapamil in a dose of 10 micrograms/kg dilated the large epicardial coronary artery, increased the coronary blood flow and heart rate and decreased the aortic pressure. A reduction of left ventricular dP/dt was observed when over 30 micrograms/kg of verapamil was administered. Nitroglycerin in a dose of 0.01 micrograms/kg dilated the large epicardial coronary artery. Other variables such as coronary blood flow, aortic pressure and heart rate were influenced when over 0.1 micrograms/kg of nitroglycerin was given. The effects of these drugs on coronary and systemic hemodynamics were augmented when incremental doses were given. Duration of the increases in coronary diameter and coronary blood flow persisted longer after verapamil than after nitroglycerin. To estimate the changes in coronary diameter, independent of flow change, the effects of verapamil (100 micrograms/kg) and nitroglycerin (20 micrograms/kg) on the large epicardial coronary artery were reexamined when the coronary blood flow was maintained constant using a cuff occluder. The extent of coronary artery dilation, unaffected by coronary blood flow, was 62% with verapamil and 100% with nitroglycerin. Thus, although nitroglycerin preferentially and flow-independently dilates the large epicardial coronary artery, dilation of the large epicardial coronary artery after verapamil is augmented by the process of flow-induced arterial relaxation.

Animals↗
PubMed1987

Successful extended cardiopulmonary preservation in the autoperfused working heart-lung preparation.

Myocardial and pulmonary preservation can be prolonged in the autoperfused working heart-lung (AWHL) preparation by metabolic substrate enhancement. However, uncontrolled pulmonary hypertension following denervation may result in extensive lung injury and occasional early failure of the preparation. To determine whether cardiopulmonary preservation could be reliably extended without development of pulmonary hypertension, six heart-lung blocks were harvested from calves, placed in a normothermic AWHL circuit, and studied. Continuous infusions of isoproterenol and dextrose/insulin were administered for the duration of the preparation. Thirteen heart-lung preparations received neither isoproterenol nor metabolic substrate and served as controls. Myocardial function was assessed by sonomicrometric techniques and pulmonary preservation was evaluated by extravascular lung water, arterial oxygenation on 100% inspired oxygen, static lung compliance, and pulmonary vascular resistance. Pulmonary hypertension developed in the control group and these animals did not survive beyond 7.5 hours. The addition of isoproterenol and metabolic substrate increased organ survival from 4.8 +/- 0.4 to 18.0 +/- 1.4 hours (p = 0.0001) and significantly reduced postexplant pulmonary vasoconstriction (p less than 0.05). Addition of isoproterenol and metabolic substrate to the AWHL model prolonged support of cardiorespiratory function and provided a reliable method for distant procurement in heart-lung transplantation.

Animals↗