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Biomedical subjects

H Adachi

Publications and source records attributed to H Adachi.

At least 271 records · Page 15Linked to original sources
PubMed1994

Isolation of Dictyostelium discoideum cytokinesis mutants by restriction enzyme-mediated integration of the blasticidin S resistance marker.

We have developed an improved REMI (restriction enzyme-mediated integration) system for generating mutant Dictyostelium cells quickly and efficiently for systematic screening of cytokinesis mutants. By means of this system, three cytokinesis mutants that grow as giant and multinucleate cells were isolated from 2,000 Dictyostelium transformants. Southern blot analysis of these mutants revealed that a single copy of the tag DNA was integrated into each genome. The tag with flanking genomic DNA at both ends was rescued from one of the mutants and reintroduced into the parental Ax2 strain. Homologous recombination of the rescued gene and the Dictyostelium genome led to the phenotypical changes expected for cytokinesis mutants.

Animals↗
PubMed1994

Implantation and growth of epidermal growth factor (EGF) receptor expressing human ovarian cancer xenografts in nude mice is dependent on EGF.

BACKGROUND: The importance of epidermal growth factor (EGF) receptor-dependent growth has not been clarified for in vivo growth of primary human ovarian cancers. METHODS: Seventeen primary human ovarian cancer tissue samples were examined for the presence of EGF receptors by a 125I-EGF-binding study. Three groups of mice were inoculated with EGF receptor expressing and not-expressing cancer tissues. The groups were as follows: control group, Sx group (mice that underwent sialoadenectomy; EGF depleted mice), and Sx+EGF (EGF-replaced) group. The ability of the inoculated tissues to implant and grow then was studied. RESULTS: Of the 17 primary ovarian cancers, 12 expressed EGF receptors and 5 did not. Eight of 12 EGF-receptor expressing cancer tissues implanted and formed growing tumors in control animals. None implanted in the Sx animals. Epidermal growth factor receptor-expressing cancers implanted in Sx animals that received EGF administration. Two of five EGF receptor-negative ovarian cancers implanted and grew in both control and Sx animals. CONCLUSION: Growth of EGF receptor-expressing primary human ovarian cancers may be dependent on EGF in vivo.

Animals↗
PubMed1994

Effects of a novel, selective and potent phosphodiesterase type V inhibitor, E4021, on myocardial ischemia in guinea pigs.

The anti-ischemic effects of a new, selective and potent cyclic 3',5'-guanosine monophosphate-specific phosphodiesterase (phosphodiesterase type V) inhibitor, sodium 1-[6-chloro-4-(3,4-methylenedioxybenzyl)aminoquinazolin-2-yl ]piperidine-4- carboxylate (E4021), in a vasopressin-induced guinea pig anginal model were examined and compared with those of coronary vasodilators with a guanylate cyclase-activating action. An intravenous injection of vasopressin (0.2 IU/kg) into anesthetized guinea pigs produced ST segment elevation on the electrocardiogram (an index of myocardial ischemia) of 0.28 +/- 0.02 mV (n = 10) from the baseline within 30 s. E4021 administered intravenously at doses of 0.03 and 0.1 mg/kg, 5 min before the injection of vasopressin, significantly inhibited the ST segment elevation to 0.15 +/- 0.03 mV (n = 6, P < 0.01) and 0.17 +/- 0.02 mV (n = 6, P < 0.01), respectively. Three guanylate cyclase activators, isosorbide dinitrate (0.1 mg/kg), nicorandil (0.1 mg/kg), and FK409 (0.3 mg/kg), also significantly reduced the ST segment elevation to 0.18 +/- 0.03, 0.11 +/- 0.02 and 0.17 +/- 0.02 mV, respectively. In a second experiment, E4021 was administered intraduodenally 30 min before the injection of vasopressin to examine its oral effectiveness. Intraduodenal E4021, at doses of 1.0 and 3.0 mg/kg, also significantly inhibited the ST segment elevation to 0.16 +/- 0.02 mV (n = 6, P < 0.01) and 0.13 +/- 0.02 mV (n = 6, P < 0.01), respectively. It is concluded that the potent phosphodiesterase type V inhibitor, E4021, administered intravenously or intraduodenally, ameliorated myocardial ischemia similarly to guanylate cyclase activators. Thus, E4021 may be an orally effective drug in the treatment of angina pectoris.

Animals↗
PubMed1994

The catalytic subunit of bovine brain platelet-activating factor acetylhydrolase is a novel type of serine esterase.

Platelet-activating factor (PAF) acetylhydrolase is the key enzyme in PAF inactivation. We recently purified one isoform of the enzyme from a bovine brain soluble fraction and revealed it as a heterotrimeric enzyme consisting of 29-, 30-, and 45-kDa subunits. Among them, the 29-kDa subunit possesses an active serine residue since diisopropyl fluorophosphate (DFP), an inhibitor of the enzyme, labeled only this subunit (Hattori, M., Arai, H., and Inoue, K. (1993) J. Biol. Chem. 268, 18748-18753). In the current study, we cloned the cDNA for the 29-kDa catalytic subunit. The predicted sequence of 232 amino acids is unique and is not homologous with those of any other proteins reported so far. When transfected into either Escherichia coli or COS7 cells, the cDNA produced PAF acetylhydrolase activity in both types of cells, indicating that this subunit alone is enough for catalysis. The recombinant 29-kDa protein was also inhibited and labeled by DFP. Furthermore, we isolated and sequenced the [3H]DFP-labeled peptide fragment, revealing that Ser47 is the active serine residue. The sequence surrounding it is different from the consensus sequence of the serine esterase family. Interestingly, the sequence of about 30 amino acids located 6 residues downstream from the active serine site exhibits significant homology to the first transmembrane region of the PAF receptor. These data demonstrate that the catalytic subunit of brain PAF acetylhydrolase is a novel type of serine esterase.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1994

Relative specificities of a series of beta-lactam-recognizing enzymes towards the side-chains of penicillins and of acyclic thioldepsipeptides.

In an attempt to understand more of the subtle differences between bacterial beta-lactamases and DD-peptidases, comparisons have been made between the specificities of these enzymes towards the phenylacetyl side chain, generally thought to be favoured by beta-lactamases, and the NN'-diacetyl-L-lysyl side chain, widely employed in low-molecular-mass substrates of DD-peptidases. These comparisons were carried out with both a penicillin and an acyclic thioldepsipeptide reaction nucleus and employing a range of both beta-lactamases and DD-peptidases. Rather contrary to general expectations, a general preference for reaction of both groups of enzymes with penicillins rather than thioldepsipeptides was observed and for the phenylacetyl rather than the NN'-diacetyl-L-lysyl side chain. Quantitative comparisons suggested that the side chains of penicillins may be bound in relatively similar sites in all of the enzymes whereas the side chains of thioldepsipeptides are more heterogeneously bound, both with respect to each other and to the comparable side chains of penicillins.

Binding Sites↗
PubMed1994

Cell type specific patterns of mRNA splicing in hepatoma cells transfected with the mutated albumin minigene of Nagase analbuminemic rats.

We constructed an SV40-derived expression vector containing a mutated albumin minigene of Nagase analbuminemic rats (NAR), and introduced it into cultured cells. Transient expression of the minigene mRNA was determined by RT-PCR. Three kinds of aberrant mRNAs were expressed by the non-hepatic cells COS-1, and the undifferentiated human hepatoma cells HLE, transfected with the minigene. Their predominant mRNA lacked exon H (delta H), while mRNAs lacking exons H and I, or exons G and H were less abundant. This pattern of the mRNAs was similar to that of albumin mRNAs in the liver of old NAR. In contrast, a differentiated type of human hepatoma cell line, HepG2, expressed only delta H mRNA, like young NAR. These findings indicate that the expression system of the mutated minigene in cultured hepatoma cells is useful for understanding two-exon-skipping of albumin pre-mRNA of NAR.

Alternative Splicing↗
PubMed1994

Miller-Dieker lissencephaly gene encodes a subunit of brain platelet-activating factor acetylhydrolase [corrected].

Platelet-activating factor (PAF) is involved in a variety of biological and pathological processes and PAF acetylhydrolase, which inactivates PAF by removing the acetyl group at the sn-2 position, is widely distributed in plasma and tissue cytosols. One isoform of PAF acetylhydrolase present in bovine brain cortex is a heterotrimer comprising subunits with relative molecular masses of 45K, 30K and 29K (ref. 4). We have now isolated the complementary DNA for the 45K subunit. Sequence analysis revealed a striking identity (99%) of the subunit with a protein encoded by the causative gene (LIS-1) for Miller-Dieker lissencephaly, a human brain malformation manifested by a smooth cerebral surface and abnormal neuronal migration. This indicates that the LIS-1 gene product is a human homologue of the 45K subunit of intracellular PAF acetylhydrolase. Our results raise the possibility that PAF and PAF acetylhydrolase are important in the formation of the brain cortex during differentiation and development.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1994

Cyclic GMP phosphodiesterase inhibitors. 2. Requirement of 6-substitution of quinazoline derivatives for potent and selective inhibitory activity.

We synthesized various 4-[[3,4-(methylenedioxy)benzyl]amino]quinazolines substituted at the 5- to 8-positions and evaluated their inhibitory activities toward cyclic GMP phosphodiesterase (cGMP-PDE) from porcine aorta. Monosubstitution at the 6-position was essential for the inhibitory activity, and the preferred substituents were compact and hydrophobic: methoxy (3b, IC50 = 0.23 microM), methyl (3c, 0.10 microM), chloro (3d, 0.019 microM), thiomethyl (3f, 0.031 microM), and cyano (3p, 0.090 microM) groups. Compounds 3b-d,f,p lacked inhibitory activity toward other PDE isozymes (all IC50 values > 100 microM), and their relaxing activities in porcine coronary arteries were well correlated with the inhibitory activities toward cGMP-PDE (r = 0.88, p < 0.05). One of these compounds, 3b, elevated the intracellular cGMP level in isolated porcine coronary arteries without causing any change in the cAMP level. We consider that this series of compounds dilates coronary arteries via potent and specific inhibition of cGMP-PDE.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1994

Effects of a pyranocoumarin compound isolated from a Chinese medicinal plant on ischemic myocardial dysfunction in anesthetized dogs.

A pyranocoumarin compound, 3'-angeloyloxy-4'-acetoxy-3',4'-dihydroseselin (Pd-Ia), isolated from Bai-Hua Qian-Hu, a Chinese medicine, is known to possess a Ca2+ channel antagonist action. We examined the effect of Pd-Ia on cardiohemodynamics and regional myocardial dysfunction after transient ischemia in anesthetized open-chest dogs. I.v. injections of Pd-Ia (0.1-3.0 mg/kg, n = 7) significantly and dose dependently increased coronary blood flow and decreased mean aortic pressure, maximal rate of rise in left ventricular pressure, rate pressure product and systemic vascular resistance, together with a slight increase in heart rate. Diltiazem (0.03-1.00 mg/kg, n = 6) showed effects on the cardiohemodynamics similar to those of Pd-Ia, except for a marked decrease in heart rate. The effects of Pd-Ia on mean aortic pressure and rate pressure product were approximately 10 times less potent than those of diltiazem. In the second experiment, the effect of a 30-min infusion of Pd-Ia (0.15 mg/kg/min) or vehicle on regional myocardial dysfunction was examined in 16 anesthetized dogs subjected to a 15-min occlusion of the left anterior descending coronary artery followed by a 3-h reperfusion. Infusion of Pd-Ia was started 15 min before coronary occlusion. The vehicle caused a decrease in percent segment shortening throughout the reperfusion period (n = 8). However, Pd-Ia at the dose that produced no significant changes in cardiohemodynamics resulted in a marked improvement in percent segment shortening of the ischemic and reperfused myocardium (n = 8, P < 0.05 vs. control group).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Antemortem diagnosis of cardiac sarcoidosis by abnormal uptake of 201Tl in bilateral hilar lymph nodes.

The antemortem diagnosis of cardiac sarcoidosis is extremely difficult. We present a patient with congestive heart failure and cardiomyopathy of unknown cause who exhibited an abnormal accumulation of 201Tl in both hilar lymph nodes in addition to a perfusion defect of the left ventricular myocardium. The findings ultimately led to a diagnosis of myocardial sarcoidosis, which was treated successfully with prednisolone. Although such uptake in the hilar nodes has rarely been reported previously, and the mechanism is not known, this was a remarkable finding in diagnosing cardiac sarcoidosis in this case. When the abnormal hilar lymph nodes uptake of 201Tl is combined with the defect in the left ventricular myocardium, we should take cardiac sarcoidosis into consideration as the cause of secondary cardiomyopathy.

Adrenal Cortex Hormones↗
PubMed1994

Role of endogenous PGE2 in osteoblastic functions of a clonal osteoblast-like cell, MC3T3-E1.

MC3T3-E1 cells actively synthesized and released prostaglandin E2 (PGE2) during culture. PGE2 release was minimal on day 9 and gradually increased with culture up to day 27. DNA content gradually increased until day 27. Alkaline phosphatase (ALP) activity increased up to day 15 and decreased thereafter. In contrast to the decrease in ALP activity, calcium accumulation increased rapidly after day 21, possibly due to mineralization by the cells. Indomethacin, a cyclooxygenase inhibitor, blocked PGE2 production completely at concentrations higher than 0.3 mumol/L. In the presence of indomethacin (3 mumol/L), DNA content was slightly decreased on day 27. Furthermore, ALP activity on day 15 was greater than that of the control and this high activity was maintained until day 27. However, calcium accumulation was not affected by the addition of indomethacin. These results suggest that endogenous PGE2 down-regulates ALP activity and slightly stimulates the proliferation of MC3T3-E1 cells as an autocrine mediator, although it does not directly influence the cells' mineralizing activity.

Alkaline Phosphatase↗
PubMed1994

Anchorage and retentive effects of a bisphosphonate (AHBuBP) on tooth movements in rats.

The purpose of this study was to examine the effect of 4-amino-1-hydroxybutylidene-1,1-bisphosphonate (AHBuBP), a potent blocker of bone resorption, on orthodontic tooth movements in rats. In the first experiment, the right and left upper first molars were moved buccally for 3 weeks with a uniform standardized expansion spring under systemic administration of AHBuBP every other day. The total tooth movement during the 3-week experimental period was 40% of that in the control at a dose of 0.5 mg P/kg. In the second experiment, the right and left upper first molars were first moved buccally for 3 weeks without AHBuBP. The spring was then removed and administration of AHBuBP was initiated. The total relapse movement during the 3-week experimental period was 50% of that in the control at a dose of 0.5 mg P/kg. Results of the first and second experiments were both dose dependent. Histologic examination showed that in the experimental animals fewer osteoclasts appeared on the alveolar bone surface, and both bone resorption and root resorption were inhibited. Inhibition of tooth movement was also observed when AHBuBP was applied topically. These results suggest that AHBuBP could be useful in enhancing anchorage or retaining teeth in orthodontic treatment.

Alendronate↗
PubMed1994

Myocardial beta-receptor and cardiac angiotensin alterations during the acute and chronic phases of viral myocarditis.

Recovery from viral myocarditis is usually excellent and complete although it occasionally results in sudden death during its acute stage. While neurohormonal mechanisms play an important role in the adaptation to heart diseases, little is known about the alteration of the neurohormonal system in viral myocarditis. Therefore, we examined the myocardial beta-adrenergic receptor and cardiac angiotensin I and II concentrations in a murine model of viral myocarditis induced by an encephalomyocarditis virus. The down-regulation of the beta 1-adrenergic receptor subtype was observed on day 10. The heart weight, heart weight/body weight ratio and myocardial necrosis were significantly increased at this stage. On day 30, the beta 2-adrenergic receptor subtype was up-regulated without up-regulation of the total beta-adrenergic receptor. Both angiotensin I and II concentrations were significantly increased with myocardial hypertrophy in the left ventricle on day 30. The up-regulation of the total beta-adrenergic receptor and beta 2-subtype was observed on day 120, but neither the angiotensin I nor II concentration was increased. Therefore, the up-regulation of the beta 2-adrenergic receptor density and the temporal increase of the angiotensin I and II concentrations in the murine ventricle during viral myocarditis may play an important role in the pathophysiology of post-viral myocarditis.

Angiotensin I↗
PubMed1994

Assessment of aortic disease using three-dimensional CT angiography.

The recently developed technique of three-dimensional CT angiography (3D-CTA) was applied to 68 patients with aortic disease. These patients were examined using a unique method of data collection: a helical scanner with continuous tube rotation and continuous table feed. The scanner was used in conjunction with administration of dynamic intravenous contrast material to enhance the vascular image. The group of patients included 35 with aortic dissection, 19 with true thoracic aneurysms, and 14 with abdominal aortic aneurysms. Three-dimensional evaluation was achieved in all patients with no complications. Surgical intervention was used in 45 patients with aortic dissections and aortic aneurysms, and 44 of these patients (98%) survived and were discharged. Preoperative 3D-CTA findings were quite similar to intraoperative findings, and were useful in determining operative procedures. Rapid and accurate assessment of aortic disease was achieved by 3D-CTA. Three-dimensional CT angiography can play an important role in the preoperative assessment of aortic dissections and aortic aneurysms leading to successful surgical treatment.

Adult↗
PubMed1994

Oxygen uptake kinetics are determined by cardiac function at onset of exercise rather than peak exercise in patients with prior myocardial infarction.

BACKGROUND: Resting cardiac function does not necessarily affect exercise capacity. However, to determine whether it affects early dynamics of oxygen uptake (VO2) during exercise, we measured VO2 during a constant work rate and during incremental exercise testing in patients with a history of myocardial infarction. VO2 kinetics and exercise capacity were compared between patients with relatively high left ventricular ejection fractions (LVEF > or = 35%, group 1) and those with lower ejection fractions (LVEF < 35%, group 2). METHODS AND RESULTS: Forty patients with a history of prior myocardial infarction (age, 57 +/- 10 years) were monitored during 6 minutes of moderate constant work rate testing (40 +/- 8 W) and during symptom-limited incremental exercise testing with a cycle ergometer. VO2 was calculated from respired gas analysis on a breath-by-breath basis. Cardiac output determinations were made with a computerized cadmium telluride detector every 10 seconds during exercise. The VO2 time constant during constant work rate exercise was slower in group 2 (58.0 +/- 7.6 seconds) compared with group 1 (45.8 +/- 10.5 seconds, P = .0002), indicating slower kinetics in group 2. The time constant for the rise in cardiac output during exercise was also slower in patients with lower EFs (63.0 +/- 12.8 versus 50.0 +/- 12.2 seconds). However, there were no differences in exercise capacity parameters, such as the VO2 or cardiac output at peak exercise, obtained during incremental exercise testing among the two groups. CONCLUSIONS: The prolonged time constant of VO2, which is primarily determined during early parts of exercise, reflects delayed cardiac output response in patients with severely impaired LV function. The time constant of VO2 during submaximal constant work rate exercise can be used as a sensitive and discriminant measure of impaired cardiac reserve in these patients.

Adult↗
PubMed1994

Effects of topical administration of a bisphosphonate (risedronate) on orthodontic tooth movements in rats.

In orthodontics, undesirable movement of anchor teeth during tooth movement and relapse of moved teeth after treatment are the main causes of unsuccessful results. If these tooth movements could be prevented with pharmacological agents, a less complex orthodontic force system and less extensive retention would be required. The purpose of this study was to examine the effect of topical administration of a bisphosphonate (risedronate), a potent blocker of bone resorption, on orthodontic tooth movements in rats. In the first experiment, both the right and left upper first molars were moved buccally with a standardized expansion spring under administration of risedronate. Risedronate solution was injected into the subperiosteum area adjacent to the left upper first molar. The right first molar served as a control with an injection of 0.9% NaCl solution. The topical administration of risedronate caused a significant and dose-dependent reduction of tooth movement after the orthodontic force was applied. In the second experiment, the right and left upper molars were first moved buccally for three weeks. The spring was then removed, and administration of risedronate was begun. The topical administration of risedronate inhibited relapse of the tooth in a dose-dependent manner. The administration of risedronate did not affect either overall growth of the animals or longitudinal growth of tibiae. These results suggest that topical application of risedronate may be helpful in anchoring and retaining teeth under orthodontic treatment.

Administration, Topical↗
PubMed1994

Epidermal growth factor promotes adipogenesis of 3T3-L1 cell in vitro.

We have reported the importance of epidermal growth factor (EGF) for the induction of obesity in mice. In this study, we studied the effects of EGF on the induction of lipogenic enzymes and on the accumulation of triglyceride in a differentiated mouse adipocyte cell in vitro. Mouse 3T3-L1 preadipocytic cells differentiated into mature adipocytes after the differentiation procedure by insulin, dexamethasone, and methyl-isobutyl-xanthine. 125I-EGF binding studies in the differentiated 3T3-L1 cells showed specific 125I-EGF bindings, and they expressed gene transcripts for EGF receptors by reverse transcription and polymerase chain reaction at all differentiative stages examined. Although EGF showed inhibitory effects on the triglyceride accumulation when administered to the preadipocytic 3T3-L1 cells, EGF enhanced the adipogenesis in the differentiated cells in dose- and time-dependent manners. Administration of EGF at 0.1-1 nM from 4 days after the differentiation procedure for 10 days, significantly enhanced the acyl-Co A synthetase and lipoprotein lipase messenger RNA levels, both of which are rate-limiting enzymes to synthesize triglyceride in adipocytes. Moreover, 0.1-1 nM EGF increased the amounts of triglyceride accumulated in the cells, in proportion to the acyl-Co A synthetase and lipoprotein lipase messenger RNA levels. EGF rather failed the adipogenesis at 10 nM. Time course studies revealed that 1 nM EGF significantly increased the intracellular triglyceride levels from 4 through 16 days administration. These results suggest that EGF shows biphasic effects on adipocytes: although EGF inhibits preadipocytes differentiation into mature adipocytes, it promotes adipogenesis in the differentiated adipocytes.

3T3 Cells↗