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Biomedical subjects

H Hama

Publications and source records attributed to H Hama.

At least 91 records · Page 5Linked to original sources
PubMed1990

[Treatment of paroxysmal nocturnal hemoglobinuria with danazol].

Glucocorticoid and androgen therapy have been used with moderate success in paroxysmal nocturnal hemoglobinuria (PNH). However, both are poorly tolerated, especially in women, although the side effects of glucocorticoid can be diminished by alternate day therapy. We have treated two patients with PNH with danazol. One of patient is man, 64 years old age with stomach cancer, and the other patient is 34-year-old man. Their disease has existed for 6-14 years. They required many blood transfusions, their hemoglobins ranging between 7.1 and 9.9 grams per deciliter. When treated with danazol by mouth, the hemoglobin level increased approximately 2 to 5 grams in each patient within 3 week, and clinical hemoglobinuria improved. None of the patients has had any side effects.

Adult↗
PubMed1989

Evaluation for roles of periventricular cholinoceptors in vasopressin secretion in response to angiotensin II and an osmotic stimulus.

In conscious rats, intracerebroventricular (i.c.v.) injections (10 microliters) of carbachol (1.4 nmol), angiotensin II (AII; 48.2 pmol) or a hypertonic solution (990 mOsm/kg) produced increases of plasma vasopressin (AVP) and arterial pressure. The effects of carbachol were inhibited not by a nicotinic cholinergic blocker hexamethonium (28 nmol), but by a muscarinic cholinergic blocker atropine (28 nmol). However, neither hexamethonium nor atropine affected the AVP and pressor responses to AII or the hypertonic solution. We concluded that periventricular cholinoceptors may not be involved in the central actions of AII and hypertonicity on AVP release and blood pressure.

Angiotensin II↗
PubMed1989

Facilitatory role of central dopamine in the osmotic release of vasopressin.

In conscious rats, intracerebroventricular (i.c.v.) injection of the dopamine antagonist haloperidol (0.15 mumol) blocked increases in plasma vasopressin (AVP) and arterial pressure caused by i.c.v. administration of a hypertonic solution (990 mOsm/kg, 10 microliters), without affecting plasma osmolality, electrolytes or hematocrit. The application of the alpha-adrenergic antagonist phenoxybenzamine (0.15 mumol), however, did not significantly inhibit the responses of plasma AVP and arterial pressure to the hypertonic solution. We concluded that brain dopamine may play a facilitatory role in the osmotically stimulated AVP secretion.

Animals↗
PubMed1989

Purification and characterization of membrane-bound 5'-nucleotidase of Vibrio parahaemolyticus.

Membrane-bound 5'-nucleotidase from Vibrio parahaemolyticus was solubilized and purified using a nonionic detergent, heptyl-beta-D-thioglucoside, and was characterized. This enzyme required Mg2+ for activity, maximum activity being observed at 5 and 20 mM Mg2+ with AMP and ATP, respectively, as substrates. Of the divalent cations tested, Mn2+ and Co2+ were able to replace Mg2+ partially, whereas Ca2+ was ineffective. Zinc strongly inhibited the enzyme activity and Ni2+ caused partial inhibition. This enzyme required Cl- for activity, the optimal concentration being 20 mM or more. The order of effectiveness of anions was Cl- greater than Br- greater than I- approximately NO3-. Sulfate and acetate were ineffective. The optimal pH was 8.0. The activity of the purified enzyme was stimulated by the addition of lipid to the assay mixture. This enzyme hydrolyzed all 5'-nucleotides tested, but did not hydrolyze 3'-nucleotides or ribose 5-phosphate. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the enzyme appeared to be a single polypeptide, with a molecular weight of 72 kDa.

5'-Nucleotidase↗
PubMed1989

Cloning and expression of the 5'-nucleotidase gene of Vibrio parahaemolyticus in Escherichia coli and overproduction of the enzyme.

The gene encoding the membrane-bound 5'-nucleotidase of Vibrio parahaemolyticus was cloned and expressed in Escherichia coli. Cells of E. coli harboring a plasmid, pNUT5, which carries the 5'-nucleotidase gene were able to grow on ATP as the sole source of carbon, although the original cells were not. The 5'-nucleotidase activity was detected in whole cells of E. coli harboring pNUT5 and in membrane vesicles prepared from these cells. Most properties of the 5'-nucleotidase produced in E. coli, that is, its requirements for Cl- and Mg2+, substrate specificity, and inhibition by Zn2+, were similar to those observed in V. parahaemolyticus, but some alterations in properties were observed: The 5'-nucleotidase was partially inducible in V. parahaemolyticus, but its expression in E. coli was completely constitutive. The specific activity of the 5'-nucleotidase in membrane vesicles of E. coli harboring the plasmid was 30 times that observed in whole cells, whereas the specific activities in membrane vesicles and in whole cells of V. parahaemolyticus were almost the same. A new, dense band of protein with an apparent molecular mass of 63 kDa was detected when membrane proteins of E. coli harboring the plasmid were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

5'-Nucleotidase↗
PubMed1988

Characterization of a novel L-serine transport system in Escherichia coli.

A novel transport system for L-serine was found in Escherichia coli cells grown on medium containing amino acid mixture. This novel system is distinguishable from the known three transport systems for L-serine, namely, the serine-threonine system, one of the leucine-isoleucine-valine systems, and the glycine-alanine system. Uptake of L-serine via this novel system was inhibited by none of the amino acids tested, indicating that it is highly specific for L-serine. This system was induced by L-leucine, but not by L-serine. The Km for L-serine was 50 microM, and the Vmax was 23 nmol/min per mg of cell protein. Transport of L-serine via this system was strongly inhibited by KCN, an inhibitor of the respiratory chain, or by carbonyl cyanide m-chlorophenylhydrazone, an H+ conductor. Uptake of H+ was induced by L-serine influx. These results indicate that an H+-serine cotransport mechanism is operative in this novel L-serine transport system.

Alanine↗
PubMed1988

Central effects of catecholamine antagonists on angiotensin-induced vasopressin secretion in conscious rats.

To evaluate the roles for catecholamines in angiotensin II (ANG II)-induced vasopressin (AVP) release, we examined in conscious rats the effects of intraventricular (ivt) administrations of catecholamine antagonists on plasma AVP responses to ivt applications of its agonists and ANG II. Plasma AVP was determined by RIA using trunk blood collected after decapitation. Dopamine (0.15 mumol), phenylephrine (an alpha-adrenergic agonist, 0.15 mumol) or ANG II (48.2 pmol) augmented plasma AVP 90 sec after the injection, whereas after isoproterenol (a beta-adrenergic agonist, 0.15 mumol) plasma AVP was unaffected. The plasma AVP responses to both dopamine and ANG II were significantly (P less than 0.01) inhibited by haloperidol (a dopamine blocker, 0.15 mumol) given 10 min before administration of these agents. Pre-administration of phenoxybenzamine (an alpha antagonist, 0.15 mumol) which was confirmed to abolish the effect of phenylephrine, or propranolol (a beta antagonist, 0.15 mumol) did not block the effect of ANG II. Administration of haloperidol, phenoxybenzamine or propranolol alone was without effect on plasma AVP level. On the basis of these results, we concluded that ANG II-induced AVP secretion may be mediated and/or modulated by dopamine.

Angiotensin II↗
PubMed1987

Properties of a Na+-coupled serine-threonine transport system in Escherichia coli.

Based on the following experimental results we conclude that the serine-threonine transport system in Escherichia coli is a Na+-coupled cotransport system. (1) Addition of serine to cell suspensions induced H+ efflux in the presence of Na+. (2) Addition of serine to cell suspensions induced Na+ uptake by cells. (3) Imposition of an artificial electrochemical potential of Na+ in starved cells induced serine uptake. Some of these phenomena were observed when threonine was added instead of serine or inhibited when cells were preincubated with threonine. The Na+/serine (threonine) cotransport system was considerably repressed when cells were grown on a mixture of amino acids. Serine transport in cells grown in the absence of amino acids mixture was stimulated by Na+. The half maximum concentration of Na+ was 21 microM. Sodium ion increased the Vmax of serine transport without affecting the Km.

Amino Acid Transport Systems↗
PubMed1987

Isolation and properties of a mutant of Escherichia coli possessing defective Na+/H+ antiporter.

A mutant of Escherichia coli with defective Na+/H+ antiporter was isolated. The rationale for its isolation was that cells possessing defective Na+/H+ antiporter, which is essential for establishment of a Na+ gradient, could not grow with a carbon source that was taken up with Na+. The mutant had no appreciable Na+/H+ antiporter activity, but its K+/H+ antiporter and Ca2+/H+ antiporter activities were normal. Judging from the reversion frequency, the defect seems to be due to a single mutation. The mutant could not grow at alkaline pH. Therefore, the Na+/H+ antiporter, but not the K+/H+ antiporter or the Ca2+/H+ antiporter, seems to be responsible for pH regulation in alkaline medium. This mutant will be useful for cloning the Na+/H+ antiporter gene and for detection of Na+-substrate cotransport systems.

Carrier Proteins↗
PubMed1987

[The sibling status effects and the personality scales of the MMPI].

The purpose of this study is to find out if the personalities of siblings are similar or different. Subjects used were Doshisha University students and members of their families, provided those families had only two children. Altogether 29 pairs of boys and their younger brothers, 47 pairs of boys and their younger sisters, 44 pairs of girls and their younger brothers, and 51 pairs of girls and their younger sisters were given the MMPI individually. Sibling status effects were found in many of the MMPI scores according to the type of sibling dyads and birth order, especially for the sibling dyad of elder brother and younger sister. Personality relationships between the first and second child showed that there were significant correlations in many MMPI scales: L, K, Pd, Pa, Pt, Sc, Si, Conflict resolution, Manifest anxiety, Repression-Sensitization, and Hostility. Among the four types of sibling dyad, the pairs of girls and their younger brothers showed the highest correlation in their personality.

Birth Order↗
PubMed1986

[A study of itch intensity in relation to two-point tactual discrimination].

This study was designed to investigate whether or not the areas of the human body most sensitive to itch stimuli are identical with the body parts least sensitive to tactual discrimination, a hypothesis which arouse from our previous studies of itching. Subjects were 12 college students (six males and six females). The itching was induced by grated Japanese yam. The body areas were the upper arm (with large two-point thresholds), the lower leg (with intermediate two-point thresholds), and the middle finger (with small two-point thresholds). An experimental session consisted of a stimulus-application period (200 s), and a post-application period (600 s) during which the itching increases markedly. (After wiping off the grated yam, itching is increased because of the needle-crystals of calcium oxalate contained in the yam peel which penetrate slightly into the skin in the process of wiping.) Self-ratings on itching and the volume of dermal blood flow were recorded during two periods. The results support our hypothesis and suggest that tactile sensation has some interaction with itching.

Adolescent↗
PubMed1985

Deletion of seven amino acid residues from the gamma subunit of Escherichia coli H+-ATPase causes total loss of F1 assembly on membranes.

A mutant gene for the gamma subunit of H+-translocating ATPase was cloned from Escherichia coli mutant NR70 isolated by B. P. Rosen [J. Bacteriol. 116, 1124-1129 (1973)]. Determination of its nucleotide sequence revealed a deletion of 21 base pairs between nucleotide residues 64 and 84, resulting in a deletion of seven amino acid residues (LysAlaMetGluMetValAla) from the amino-terminal portion. This deletion resulted in the loss of a hydrophobic domain of the subunit estimated by an analysis of its hydropathic character. Since F1 subunits are reported not to be assembled on the normal F0 portion of NR70, it is concluded that the hydrophobic domain deleted in the mutant subunit is important for assembly of the F1 portion. Introduction of a plasmid pNR70 carrying the mutant allele of NR70 into a wild-type strain gave no recombinants resistant to neomycin. This result suggested that the neomycin-resistant phenotype is not directly related to the defect in the gamma subunit of NR70.

Amino Acid Sequence↗
PubMed1985

Plasma vasopressin response to peripheral administration of angiotensin in conscious rats.

To assess a role for peripherally administered angiotensin II (ANG II) in regulating vasopressin (antidiuretic hormone, ADH) release, the effects on plasma ANG II and ADH of intraperitoneal injections of ANG II dissolved in various solutions were examined in conscious rats. Plasma ANG II and ADH were determined by radioimmunoassay using the trunk blood collected after decapitation. Injections of 150 mM NaCl containing ANG II (6, 12, or 24 micrograms X 2 ml-1 X 100 g body wt-1) caused dose-related increases in plasma ANG II 15 and 30 min after, but plasma ADH remained unchanged. The lack of effect on plasma ADH of the ANG II dissolved in isotonic saline was also confirmed in another series of experiments in which the solution with a higher ANG II concentration was loaded by much smaller injection volume (14.3 micrograms X 0.1 ml-1 X 100 g-1). However, when given together with 600 mM NaCl, ANG II (8 micrograms X 2 ml-1 X 100 g-1) significantly potentiated the plasma ADH response to the vehicle at 15, 30, and 60 min, without affecting those of plasma osmolality, sodium, and hematocrit. The elevations of plasma ANG II and osmolality brought about by the treatment were comparable with those previously observed in rats deprived of water for 46 h. ANG II was without effect on the plasma ADH responses to the intraperitoneal injections of hypertonic sucrose or mannitol solution that did not alter plasma sodium, although these solutions were equipotent to 600 mM NaCl in augmenting plasma ADH and osmolality.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗
PubMed1985

[Change in conflict strength measured by Color-Word Test in childhood, adulthood, and the aged].

A life span survey of conflict induced in color naming when words and colors appear in incongruent combination was carried out. Subjects' ages ranged from six years to 89 years, totaling 721. As the index of conflict, (C-B)/A was used. The result indicated that conflict scores were highest in six-year-old children and the next highest in the eldery of 70 to 89 years. The result of ANOVA indicated no sex difference on conflict scores, but showed a difference in faster performance by females on the color and color-word cards. The result suggested that six-year olds are immature in cognitive ability and that the 70-year olds and above declined in their cognitive ability. The elevation of conflict scores in 10 years may be due to the stage of puberty.

Adolescent↗