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Biomedical subjects

H Handa

Publications and source records attributed to H Handa.

At least 217 records · Page 12Linked to original sources
PubMed1991

Inhibition of prostaglandin E2 and superoxide anion production in rat peritoneal macrophages by the calcium antagonists nifedipine and nisoldipine.

In order to clarify the possibility of an antiatherogenic action of the calcium antagonists nifedipine (CAS 21829-25-4) and nisoldipine (CAS 63675-72-9) the effect of nifedipine and nisoldipine on phorbol myristate acetate (PMA)- and calcium ionophore A23187-stimulated O2- and PGE2 production from macrophages was investigated. Nifedipine and nisoldipine inhibited dose-dependently PMA-stimulated O2- and PGE2 production, but not A23187-stimulated PGE2 production. The 50% inhibitory concentration (IC50) of nifedipine and nisoldipine for PMA-stimulated O2- production were 60 and 8 mumol/l, respectively, whereas those for A23187-stimulated O2- were 9.3 and 2.0 mumol/l. IC50 of nifedipine and nisoldipine for PMA-stimulated PGE2 production were 3.0 and 2.8 mumol/l, respectively. The release of [1-14C]-arachidonic acid from labeled macrophages stimulated with PMA was inhibited approximately by 39 to 43% in the presence of 20 mumol/l nifedipine and nisoldipine. The increase of (Ca2+)i in macrophages induced by A23187 could not be attenuated by nifedipine and nisoldipine, and (Ca2+)i level did not alter when stimulated with PMA. These results suggest that the inhibitory mechanism of nifedipine and nisoldipine for O2- production from the macrophages appears to directly inhibit the enzyme system of the NADPH-oxidase complex through the activation of protein kinase C, and that the inhibition of PMA-stimulated PGE2 production may be due to a decrease of phospholipase A2 through protein kinase C. On the basis of the inhibitory action on O2- and PGE2 production from the macrophages, a possible mechanism of antiatherogenic effect of calcium antagonists was discussed.

Animals↗
PubMed1991

Establishment of epithelial cell lines from human and mouse thymus immortalized by the 12S adenoviral E1a gene product.

To understand the role of thymic epithelial cells in the development of immature thymocytes, the establishment and cloning of thymic epithelial cell lines must be required. In the present study, we established human and mouse thymic epithelial cell lines through the immortalization by the transfection of cDNA sequences of adenoviral E1a 12S mRNA. This procedure resulted in the isolation of five stable cell lines (one human cell line and four mouse cell lines). These cell lines were positive in cytokeratin demonstrated by immunohistochemistry. Electron microscopic study revealed that they had bundles of tonofilaments and desmosome-like tight junctions. These findings indicate that the cell lines immortalized by E1a gene have retained the properties of epithelial cells. MHC class II antigens were not expressed on these cell lines. When interferon-gamma was added to the cultured epithelial cell lines, MHC class II antigens were induced in their cytoplasm and on their surface membrane, demonstrated by immunohistochemical and immunofluorescent studies. It is suggested that these stable cell lines from human and mouse thymus might serve a good tool for the further study of thymocytes differentiation and of unknown cytokines derived from thymus epithelium.

Animals↗
PubMed1991

Calcium induced differentiation of SV40 immortalized human epidermal keratinocytes cultured in a defined medium.

Human epidermal keratinocytes, immortalized by the introduction of SV40-adenovirus recombinants (9), were maintained in a low calcium (0.15 mM) defined medium. When differentiation was induced by a higher extracellular calcium concentration (1.5 mM), these cells altered in shape and developed stratification with formation of desmosomes, while they demonstrated limited terminal keratinization. The expression of involucrin, one of the precursor proteins of the cornified envelope, became elevated as the cell density increased, but was not affected by calcium. These results indicate that the SV40 immortalized human keratinocytes, maintained in a low calcium defined medium, partially respond to changes in extracellular calcium concentration.

Calcium↗
PubMed1991

[The responses of somatosensory evoked potentials and cerebral blood flow to acetazolamide in patients with occlusive carotid disease].

The correlation between somatosensory evoked potential (SEP) and regional cerebral blood flow (rCBF) changes after acetazolamide administration was studied in six patients presented with transient ischemic attack (TIA) or minor completed stroke. All patients had no or only localized low density area on computed tomography, and severe occlusive disease in the ipsilateral common or internal carotid artery on cerebral angiography. In two patients with internal carotid artery occlusion, both marked decrease in ipsilateral N20 amplitude and prolongation of ipsilateral N20 latency were observed from 5-10 minutes after acetazolamide injection. These changes gradually improved and resolved 30-45 minutes after acetazolamide injection. In these cases, stable xenon CT revealed paradoxical rCBF decrease in the territory of the ipsilateral middle cerebral artery after acetazolamide injection. Especially, rCBF in the ipsilateral centrum semiovale fell to less than 20 ml/100 g/min. The other patients showed no change in SEPs and no paradoxical decrease in rCBF after acetazolamide injection. These results suggest that SEP test with acetazolamide loading could be valuable to evaluate a certain group of the patients with severely disturbed cerebral perfusion reserve in the carotid territory and suitable candidate for extracranial-intracranial arterial bypass (EC/IC bypass), although further investigations is needed.

Acetazolamide↗
PubMed1991

[Association of an epidermoid tumor with a cerebral aneurysm on the contralateral internal carotid artery].

A 71-year-old female was evaluated for a sudden loss of consciousness. Initial computed tomography and cerebral angiography revealed a severe subarachnoid hemorrhage, a large cystic lesion in the left occipital region, and an aneurysm at the bifurcation of the internal carotid and the posterior communicating artery on the right side. As the subarachnoid hemorrhage was thought to be due to rupture of the aneurysm, we attempted to clip the aneurysmal neck at first, and 2 weeks later the cystic tumor was removed for the purpose of internal decompression. The extirpated specimen proved to be an epidermoid tumor. Association of a brain tumor and an cerebral aneurysm is very rare, especially a combination of an epidermoid tumor and a cerebral aneurysm, and until now only 2 cases have been reported to the best of our knowledge. Moreover, the epidermoid tumor of our case was located intracerebrally. The phenomenon that the internal carotid aneurysm was on the left side and the tumor on the right side may suggest that these 2 lesions originated quite coincidentally. It is controversial to decide which lesion and when to treat first in a case of association of a tumor and an aneurysm, and we discussed as to the surgical therapy reviewing literature.

Aged↗
PubMed1991

[SEP monitoring during balloon occlusion test or operation for vertebro-basilar aneurysms].

SEP (somatosensory evoked potential) monitoring was carried out on seven patients with vertebro-basilar aneurysms during balloon occlusion test, during operation, or after operation. In the patient (case 5) with basilar tip aneurysm, the amplitude of N20 remarkably decreased and this finding closely correlated with disturbed consciousness during transient balloon occlusion of the basilar artery. In another patient (case 6) with vertebral dissecting aneurysm, cerebellar retraction caused transient prolongation of N20 latency during operation. In another case, postoperative SEP monitoring revealed marked reduction of N20 amplitude in the patient (case 7) who showed disturbed consciousness and bilateral oculomotor palsy after operation for basilar aneurysms, but who showed no abnormality in postoperative ABR (auditory evoked brainstem response). The other four patients showed no neurological deterioration and no SEP change during transient balloon occlusion of the parent arteries. Because of the high rate of "false-negative" findings, it remains unclear whether SEP monitoring during surgery for vertebrobasilar aneurysms is of value to predict postoperative deficit due to brainstem ischemia. In our study, however, the changes of SEP were well correlated with neurological deterioration and/or the location of postoperative infarction. In conclusion, SEP monitoring during balloon occlusion tests or operations for vertebro-basilar aneurysms is considered to be useful in predicting ischemic complication of the brainstem caused by the occlusion of the parent artery. However other methodologies have to be developed in order to monitor the pyramidal tract and reticular activating system of the brainstem more accurately.

Adolescent↗
PubMed1990

Strain-specific lethal effect of the adenovirus E1a protein on Saccharomyces cerevisiae.

Various adenovirus E1a proteins, including 13S protein, 12S protein and three other derivatives of 13S protein with deletions were expressed in Saccharomyces cerevisiae. Both the C-terminal 67 residues and the 13S unique domain are required for the nuclear targeting in yeast. The N-terminus containing multiple functional domains appears to be involved in the G1 arrest of diploid yeast and two other regions, the region containing amino acid residues between 122 and 139, and the 67 residues of the C-terminus are required for the lethal effect on haploid yeast. The latter effect, however, is dependent on strains. Thus, the yeast system may be utilized for functional dissection of E1a protein by further analyzing metabolic consequences.

Adenoviridae↗
PubMed1990

Transcription factor E4TF1 contains two subunits with different functions.

The transcription factor E4TF1 stimulates transcription from the adenovirus early region 4 promoter by binding to a specific promoter element. E4TF1 has been purified to homogeneity from HeLa cells by sequence-specific DNA affinity chromatography and characterized. E4TF1 is composed of at least two distinct subunits identified as 60 kd and 53 kd polypeptides. The 60 kd protein alone is able to bind to the specific DNA sequence but not to stimulate transcription in vitro. The 53 kd protein alone neither binds to DNA nor stimulates transcription in vitro. However, the 53 kd protein is able to interact with the 60 kd protein and the interaction confers the ability to stimulate transcription in vitro and to increase the DNA binding affinity of the 60 kd protein. This study provides evidence that the interaction between the two different subunits of E4TF1 is required for it to function as a transcription factor, and that one of the subunits binds to a specific DNA sequence and the other works as a modulator.

Base Sequence↗
PubMed1990

In vivo inhibition of superoxide production and protein kinase C activity in macrophages from vitamin E-treated rats.

Rat peritoneal macrophages, which were induced by intraperitoneal injection of vitamin E for 6 successive days, contained 387.6 to 569.0 ng alpha-tocopherol/10(6) cells and produced 0.9 to 1.5 nmol O2-/min/10(6) cells following stimulation by phorbol myristate acetate (PMA). On the other hand, control macrophages contained 1.7 ng alpha-tocopherol/10(6) cells and produced 3.9 to 4.5 nmol O2-/min/10(6) cells. The particulate fraction of macrophages from vitamin E-treated rats contained 285.2 to 294.4 ng alpha-tocopherol/10(6) cells and showed scarcely any protein kinase C activity, whereas the specific activity of control rats showed 323 to 357 pmol/min/mg protein. From these results, we concluded that vitamin E seems to decrease O2- production from macrophages stimulated with PMA through inhibition of protein kinase C.

Animals↗
PubMed1990

[A latent form of essential thrombocythemia presented as portal hypertension and associated with acquired von Willebrand syndrome].

A 32 year-old male patient was admitted to our hospital because of abdominal tumor. The examination on admission showed massive splenomegaly and esophageal varices although peripheral blood cell counts were within normal limits. Exploratory laparotomy was performed with the diagnosis of portal hypertension and revealed the multiple thrombus formations in the splenic vein and the extramedullary hematopoietic findings in the spleen by the microscopic examination. In vitro colony forming assay showed the formation of spontaneous erythroid colonies in cultures of progenitor cells (from peripheral blood mononuclear cells) in erythropoietin-poor medium. Increasing thrombocytosis was observed immediately after splenectomy, and hemorrhagic diathesis of nasal bleeding and gastrointestinal bleeding were also detected. The analysis of plasma von Willebrand factor (vWF) revealed the decrease of ristocetin cofactor activity and the lack of large multimeric components of vWF. These abnormal findings observed after splenectomy led to recovery through the administration of busulfan with the improvement of thrombocytosis. Accordingly, the course of the disease clearly indicated it to be the essential thrombocythemia represented as portal vein thrombosis and in latent form with normal cell counts in peripheral blood at the time of diagnosis, and subsequently, to develop into a full-blown form associated with acquired von Willebrand syndrome following splenectomy.

Adult↗
PubMed1989

Purification of DNA-binding transcription factors by their selective adsorption on the affinity latex particles.

A simple method with the use of affinity latex particles has been developed for the fast and efficient purification of sequence-specific DNA-binding proteins on the basis of their ability to selectively bind to their target sequences. Complementary oligodeoxynucleotides that contained a recognition site for a sequence-specific DNA-binding protein were chemically synthesized, annealed and ligated to give oligomers. The oligomers were coupled to latex particles, composed of polyglycidyl methacrylate, using cyanogen bromide to yield affinity latex particles. The concentration of covalently bound DNA on the affinity latex particles was 6 times as much DNA per ml as that in the Sepharose resin conventionally used. By sequential batch-wise procedures with the affinity particles, one of the sequence-specific DNA binding transcription factors, ATF or E4TF3, was quickly and efficiently purified to homogeneity from either a protein fraction in which the factor was enriched or a crude cell extract.

Activating Transcription Factors↗
PubMed1989

Effect of DNA supercoiling on in vitro transcription from the adenovirus early region 4.

The effect of DNA supercoiling on in vitro transcription from the early region 4 (E4) promoter of adenovirus type 5 (Ad5) has been investigated by using a cell-free transcription system that maintains supercoiled DNA templates. The supercoiled DNAs yield several-fold higher levels of E4 transcripts and more faithfully reflect the regulation of in vivo transcription than the linear DNAs.

Adenoviridae↗
PubMed1989

Repression of cytochrome P-450c gene expression by cotransfection with adenovirus E1a DNA.

Gene expression of rat cytochrome P-450c (P-450c) depends upon inducible enhancers scattered in the 5'-upstream region of the gene. We show that expression of the P-450c gene is repressed by contransfection with adenovirus E1a DNA, regardless of the presence or absence of inducers, in a transient expression system of HeLa cells. Since cotransfection of either 13S or 12S E1a cDNA was effective in the repression, the region necessary for repression could be separated from that of transactivation of other adenovirus early genes. Moreover, we investigated the regions responsible for the inhibitory activity using in-frame deletion mutants lacking internal or external portions of the E1a proteins. The sequence responsible for the repression was located in the amino-terminal half of the E1a proteins. The inducible expression of the chimeric plasmid containing a 24-base-pair enhancer sequence of the P-450c gene placed in a heterologous promoter of SV40 was repressed by cotransfection with E1a DNA, suggesting strongly that the inhibitory effect of the E1a proteins upon P-450c gene expression was caused by blocking the enhancer activity.

Adenoviridae↗
PubMed1989

Transcription in the reverse orientation at either terminus of the adenovirus type 5 genome.

The right terminus of the adenovirus type 5 (Ad5) genome, which contained the early-region 4 (E4) promoter, was capable of initiating transcription in the reverse orientation in in vitro and in vivo assays. Multiple cis-acting elements, required for original-oriented transcription, were also important for reverse-oriented transcription except for the original TATA box. We constructed a plasmid in which the E4 promoter region was linked to the chloramphenicol acetyltransferase gene in the original orientation and linked to the lacZ gene in the reverse orientation and tested the ability of a co-transfected E1A gene to stimulate transcription in both orientations. Activities of transcription in both orientations were stimulated 6- to 10-fold in this assay. More than one cis-acting element was necessary for the stimulation. The region between -39 and -177 was necessary for the E1A-mediated trans-activation of transcription in both orientations, indicating that the region functioned in a bidirectional manner. The activity of transcription in the reverse orientation was similarly detected at the left terminus of the Ad genome and the activity was stimulated several-fold by E1A gene products.

Adenoviridae↗
PubMed1989

A novel kinin, Met-Ile-Ser-bradykinin (Met-T-kinin) is released from T-kininogen by an acid proteinase of granulomatous tissues in rats.

Acid proteinase of granulomatous tissues in rats with carrageenin-induced inflammation released two types of kinin from T-kininogen. The kinin was identified as Ile-Ser-bradykinin (T-kinin) and a novel kinin, Met-Ile-Ser-bradykinin (Met-T-kinin), from determination of its amino acid composition and its immunoreactivity toward anti-bradykinin antiserum. The release of T-kinin and Met-T-kinin from T-kininogen were found to occur by consecutive cleavage by cathepsin D and 72 kDa protease.

Amino Acids↗
PubMed1989

Glandular kallikrein, renin and angiotensin converting enzyme of diabetic and hypertensive rats.

To clarify the relationship between kallikrein-kinin and renin-angiotensin systems, glandular kallikrein, renin and angiotensin converting enzyme in the submandibular gland, the kidney and plasma were investigated in streptozotocin diabetic and spontaneously hypertensive rats. Kallikrein content in the submandibular gland, the kidney and plasma of diabetic rats was found to be decreased compared with nondiabetic controls. Renin activity in diabetic rats was also reduced in the submandibular gland, but the activity showed no significant changes in the kidney and plasma. The activity of angiotensin converting enzyme (ACE) in plasma significantly increased in diabetic rats. On the other hand, kallikrein content in hypertensive rats was depressed in the kidney, while the content was unchanged in the submandibular gland and plasma. Renin activity in hypertensive rats was found to be higher than that of normotensive rats in the submandibular gland, but the activity showed no remarkable changes in the kidney and plasma. ACE activity in plasma markedly decreased in hypertensive rats in contrast to diabetic rats. In hypertensive-diabetic rats, changes in the levels of these enzymes in tested materials were similar to those of diabetic rats. From these results it is reasonable to assume that (1) reduced kallikrein generation and elevated ACE activity may induce impaired kinin formation and contribute to the development of diabetes mellitus apart from the presence of hypertension and (2) low kallikrein content in the kidney could cause hypertension.

Animals↗