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Biomedical subjects

K Murakawa

Publications and source records attributed to K Murakawa.

At least 55 records · Page 3Linked to original sources
PubMed1994

Chromosomal assignments of novel genes expressed in HL60 granulocytes.

By collecting 3'-directed cDNA sequences called gene signatures (GSs) on a large scale, it is possible to make an expression profile of genes in a particular tissue, as well as discovering a number of novel genes. A total of 305 novel GSs collected from granulocytoid cells derived from HL60, a human promyelocytic leukemia cell line, by exposure to dimethyl sulfoxide were radiolabeled and used for Southern blot analyses to determine the copy number of the corresponding genes. Of these, 198 GSs identified as representing single-copy genes were then used as probes for hybridization analyses using a monochromosomal hybrid cell DNA panel. Sixty-nine of them were assigned to individual chromosomes. These results demonstrate that the chromosomal distribution of the GSs seems not to be proportional to the cytogenetic length of each chromosome.

Animals↗
PubMed1994

Chromosomal assignment of short cDNA sequences by PCR using overlapping and tailed short primers.

Overlapping primers and tailed short primers are effective agents for mapping very short cDNA sequences. By using such primers, human cDNAs as short as 32 nucleotides in length can produce PCR bands. Using these and other primers of ordinary size, 44 cDNAs were assigned to chromosomes, of which 24 were assigned to single chromosomes, and 2 were assigned to two chromosomes and two were assigned to three chromosomes, respectively. Among the 24 cDNAs, all of which matched GenBank entries, 6 cDNAs were observed to map to the same chromosomes as reported previously.

Animals↗
PubMed1994

[Development of the brainstem and cerebellum in autistic children].

Studies of magnetic resonance images have revealed morphological disorders of the brainstem and cerebellum in autistic children and adults. When we studied development of the brainstem and cerebellum in autistic patients, these structures were significantly smaller in autistic patients than in controls. Although the brainstem and cerebellum significantly increased in size with age in both groups, the development of the pons, cerebellar vermis I-V and cerebellar vermis VI-VII was significantly more rapid in autistic patients than in controls. However, the development of the other brain structures in the posterior fossa did not differ between autistic patients and controls. The regression intercepts of the brainstem and cerebellum as well as those of their components were significantly smaller in autistic patients than in controls. These results suggested that significant anatomical changes took place in the posterior fossa brain structures in the prenatal period in autistic children, but were not progressive.

Adolescent↗
PubMed1994

[Circulatory effects of stellate ganglion block and high thoracic epidural block].

A comparative study of the circulatory effects of stellate ganglion block (SGB) and high thoracic epidural block (TEB) was conducted in 11 patients. Although blood pressure and heart rate showed no significant changes even after SGB, they both decreased significantly following TEB. The blood flow in the common carotid artery (CCA) increased markedly at 5 minutes after performing SGB, and at 20 minutes it reached its peak value of 163.5 +/- 7.8%, and the increase remained significant up to 75 minutes. On the other hand, it increased significantly from 5 minutes after performing TEB and reached its peak of 122.2 +/- 7.6% at 15 minutes, and this increase remained significant up to 60 minutes. In comparing these two nerve blocks, the blood flow in the CCA showed a more marked increase following SGB than after TEB from 5 to 60 minutes after performing. The blood flow rate in the CCA increased markedly from 5 minutes after performing SGB, reached its peak of 139.1 +/- 11.3% at 20 minutes, and this increase remained significant up to 60 minutes thereafter. After performing TEB no significant changes were observed. In comparing SGB and TEB, from 5 to 60 minutes after performing, the rate became markedly faster after SGB than after TEB. The vascular diameter of the CCA from 5 minutes after performing SGB showed a slight but significant enlargement, and at 20 minutes it reached its maximum of 111.7 +/- 3.0%, and this significant enlargement persisted up to 60 minutes. From 10 minutes after performing TEB, it showed a slight but significant enlargement.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Relationship between the regression of left ventricular hypertrophy and the changes in circadian blood pressure after long-term treatment with enalapril in hypertensive patients.

The ambulatory blood pressure (BP) was recorded for 24 hours in 28 untreated hypertensive patients, and mean values of systolic (SBP) and diastolic BP (DBP) were measured over 24 hours, during the day-time (6:00 to 19:30), and during the night-time (20:00 to 5:30). M-mode echocardiography was performed and several parameters of left ventricular size were calculated. In addition, 13 men of 18 patients with left ventricular hypertrophy (LVH) received long-term treatment with enalapril, and ambulatory BP monitoring and echocardiographic measurement were performed in 10 of these patients 6 months after active treatment ended. In all 28 patients, left ventricular mass index (LVMI) was significantly related to 24-hour, day-time and night-time SBP. Other parameters of hypertrophy were correlated with 24-hour and/or night-time BP, but not with day-time BP. In patients with LVH, night-time DBP was significantly higher and the night-time decline in DBP was significantly less than in those without LVH. The 6-month treatment with enalapril clearly decreased casual and ambulatory BP and reduced LVMI. The reduction of LVMI was strongly correlated with the decrease in night-time SBP and DBP compared with the decrease in day-time BP. These observations indicate that LVH is related to 24-hour BP (especially night-time BP) and that the regression of this condition may be related to a decline in night-time BP.

Adult↗
PubMed1994

[Circulatory effects of stellate ganglion block in idiopathic facial palsy].

The circulatory effects of stellate ganglion block (SGB) on the blood flow through the common carotid artery were determined in 35 patients in acute phase of idiopathic facial palsy (Bell's palsy). SGB was performed by para-tracheal approach with 8 ml of 1% mepivacaine. The blood flow was measured with an ultrasonic blood flowmeter before and 30 minutes after SGB at both sides of the common carotid artery in 20 cases. Measurement was performed continuously for 90 minutes on the palsy side in the other 15 patients. Before SGB, there were no significant differences between the blood flow of the palsy side and the intact side. Thirty minutes after SGB, the blood flow markedly increased to 169.4 +/- 6.2% on the performed side with no change on the non-performed side in 20 cases. In the other 15 patients, the blood flow increased significantly 5 minutes after SGB and reached its peak of 179.7 +/- 11.1% at 20 minutes later. This increase continued for 75 minutes after SGB. It is well known that impaired microcirculation in the facial nerve has an important role in the pathophysiology of Bell's palsy. In view of the fact that the nutrient arteries for the facial nerve are the peripheral branches of the external carotid artery, we believe that SGB which causes significant increase in the blood flow through the common carotid artery is an effective treatment in Bell's palsy.

Adolescent↗
PubMed1994

[MRI measurements of the brain stem and cerebellum in high functioning autistic children].

To determine involvements of the brain stem and/or cerebellum in autism, we compared midsagittal magnetic resonance images of the brains of high functioning autistic children with those of normal controls. We found that the midbrain and medulla oblongata were significantly smaller in these autistic children than in the control children. The pons area did not differ between the two groups, nor was there any difference in the cerebellar vermis area. The ratio of the brain stem and cerebellum to the posterior fossa area did not differ significantly between the high functioning autistic and the control children. The development of the cerebellar vermis area was delayed in autistic children as compared with that in the control children. Thus, it was suggested that significant anatomical changes in the midbrain and medulla oblongata existed in the autistic children.

Aging↗
PubMed1993

Serial changes in atrial and brain natriuretic peptides in patients with acute myocardial infarction treated with early coronary angioplasty.

To examine the role of brain natriuretic peptide (BNP) in acute myocardial infarction (AMI), we measured the plasma concentration of immunoreactive (ir) BNP together with that of atrial natriuretic peptide (ANP) over the 4-week course of AMI in 16 patients treated with early coronary angioplasty. Both the plasma ir-ANP and ir-BNP levels were increased on the first day of the infarction compared with the values in normal subjects. During the clinical course of the infarction, the plasma ir-ANP concentration soon decreased, while the plasma ir-BNP level remained elevated at 2 weeks after the infarction, also exhibiting a high level at 4 weeks. Plasma ir-BNP levels on day 1 or days 14 and 28 were inversely correlated with left ventricular ejection fraction obtained by left ventriculography at the acute or chronic phase, respectively. Plasma ir-BNP concentrations on days 14 and 28 were positively correlated with the maximal myosin light chain I level, an indicator of infarct size. These observations suggest that the plasma ir-BNP level increased to compensate for the ventricular dysfunction associated with the size of the infarct in AMI. BNP may act as a cardiac hormone in AMI, differing somewhat from ANP in its synthetic, secretory, or clearance behavior.

Angioplasty, Balloon, Coronary↗
PubMed1993

Stimulation of endothelin-1 release by low density and very low density lipoproteins in cultured human endothelial cells.

To examine the effects of lipoproteins on the secretion of endothelin-1 from endothelial cells, we measured immunoreactive (ir) endothelin-1 release from cultured human umbilical vein endothelial cells in the presence or absence of various concentrations of native low density lipoprotein (LDL), oxidized LDL, and very low density lipoprotein (VLDL). Cultured endothelial cells secreted ir-endothelin-1 into serum-free medium in a time-dependent manner, and the secretion was clearly stimulated following a 15-24-h incubation with 10 micrograms/ml oxidized LDL. The secretion of ir-endothelin-1 increased in a dose-dependent manner after a 24-h incubation with oxidized LDL, while only a high dose of native LDL and VLDL significantly increased ir-endothelin-1 secretion. The release of ir-endothelin-1 stimulated by 20 micrograms/ml oxidized LDL was reproduced by the same concentration of acetylated LDL but not native LDL. These observations indicate that the release of ir-endothelin-1 from endothelial cells is stimulated by lipoproteins, in particular by oxidized LDL, probably through the endothelial scavenger receptor. This increase in ir-endothelin-1 release induced by oxidized LDL may contribute to the development of atherosclerotic vascular lesions.

Cells, Cultured↗
PubMed1993

Effect of endothelin receptor antagonist, BQ-123, on Ca2+ signaling in cultured rat mesangial cells.

Endothelin (ET)-1 causes mesangial cell contraction and proliferation. The present study was designed to evaluate the functional ET receptor subtype in cultured rat mesangial cells by measuring intracellular Ca2+ signaling with the use of a newly synthesized ET receptor type A selective antagonist-BQ123. The ET-1, ET-2 and ET-3 increased intracellular Ca2+ level in a dose-dependent manner. BQ-123 suppressed intracellular Ca2+ elevation in response to ET-1 in a dose-dependent manner with its half maximal inhibition value of 28 nM. BQ-123 (10(-6) M) did not affect ET-3 (10(-7) M)-induced Ca2+ response. The peak Ca2+ levels after addition of ET-3 without BQ-123 were similar to those in response to ET-1, ET-2 and ET-3 in the presence of BQ-123. Northern blot analysis showed that cultured mesangial cells expressed both ETA and ETB receptor mRNA. These results suggest that cultured mesangial cells have, at least, two types of functional receptors, one of which is an ETA receptor.

Amino Acid Sequence↗
PubMed1993

Effect of heparin on endothelin-1 production by cultured human endothelial cells.

Heparin shows a blood pressure-lowering effect in various hypertensive rat models. This study was designed to examine the effect of heparin on vasoconstrictor endothelin-1 (ET-1) production by cultured human umbilical vein endothelial cells (HUVECs). ET-1 and cyclic GMP levels in the medium were determined by radioimmunoassay. ET-1 mRNA was quantified by densitometric Northern blot analysis. ET-1 was released into the medium in a time-dependent manner, and its release was augmented by thrombin (10 U/ml). Heparin suppressed both basal and thrombin-stimulated ET-1 secretion and its mRNA expression in a dose-dependent manner. Heparin suppressed ET-1 mRNA expression in a time-dependent fashion. Heparin did not suppress both basal and thrombin-stimulated ET-1 production in the presence of NG-monomethyl-L-arginine (L-NMMA) (10(-5) M). The production of cGMP stimulated by thrombin was significantly enhanced by heparin, but not in the presence of L-NMMA (10(-5) M). Heparin may suppress vasoconstrictor ET-1 production mediated by the enhancement of endothelium-derived nitric oxide in HUVECs.

Blotting, Northern↗
PubMed1993

Brainstem involvement in high functioning autistic children.

To determine involvements of the brainstem and/or cerebellum in autism, we compared midsagittal magnetic resonance images of the brains of high functioning autistic children with those of normal controls. We found that the midbrain and medulla oblongata were significantly smaller in these autistic children than in the control children. The pons area did not differ between the two groups, nor was there any difference in the cerebellar vermis area. The ratio of the brain stem and cerebellum to the posterior fossa area did not differ significantly between the high functioning autistic and the control children. A positive correlation between age and area of the cerebellar vermis was observed in autistic children but not in control children. Thus, it was suggested that significant anatomical changes in the midbrain and medulla oblongata existed in the autistic children and that growth of the cerebellar vermis in autistic children was different from normal children.

Adolescent↗
PubMed1993

Interaction between a phorbol ester and dopamine DA1 receptors on vascular smooth muscle.

The interaction between dopamine DA1 receptors and a phorbol ester was studied to elucidate the role of protein kinase C in the response of this receptor. The in vitro binding of [3H]Sch 23390 to DA1 receptor sites on vascular smooth muscle cells was saturable. The extent of [3H]Sch 23390 binding to phorbol ester-treated cells was increased without any change in the dissociation constant. The production of adenosine 3',5'-cyclic monophosphate (cAMP) in response to DA1 receptor stimulation was enhanced by preincubation of vascular smooth muscle cells with the phorbol ester for 4 h. However, no enhancement was observed when the medium used for preincubation was supplemented with a protein kinase C inhibitor. Direct stimulation of stimulatory guanine nucleotide-binding regulatory protein with 5-guanylylimidodiphosphate and direct stimulation of adenylate cyclase with forskolin produced no significant differences in cyclase levels between phorbol ester-treated and untreated cells. These results suggest that activation of protein kinase C triggers an increase in the membrane expression of DA1 receptors, thereby enhancing receptor-coupled cAMP generation.

Adenylyl Cyclases↗
PubMed1993

Natriuretic peptides inhibit mesangial cell production of endothelin induced by arginine vasopressin.

The present study examined the effects of atrial, brain, and C-type natriuretic peptides (ANP, BNP, and CNP, respectively) on endothelin-1 (ET-1) secretion after stimulation with arginine vasopressin (AVP), using cultured rat glomerular mesangial cells. AVP stimulated immunoreactive (ir) ET-1 secretion in a concentration-dependent manner via a receptor-mediated process. Rat ANP-(1-28) and rat BNP-45 potently inhibited this stimulated secretion in a concentration-dependent manner. Inhibition by ANP and BNP of AVP-stimulated ET-1 secretion was paralleled by an increase in the medium level of guanosine 3',5'-cyclic monophosphate (cGMP). The addition of a cGMP analogue, 8-bromo-cGMP, reduced the stimulated ET-1 secretion. CNP was much less effective than rat ANP-(1-28) or rat BNP-45 with respect to inhibiting irET-1 secretion and increasing cGMP levels. High-performance liquid chromatography indicated that the major component of irET-1 in the culture medium corresponds to ET-1-(1-21). These findings indicate that AVP stimulates ET-1 secretion in cultured rat mesangial cells and that rat ANP and BNP inhibit this stimulated secretion, probably through a cGMP-dependent process.

Animals↗
PubMed1993

Brainstem and cerebellar vermis involvement in autistic children.

Recent reports have suggested functional abnormalities of the brain stem in autistic children, and structural abnormalities have also been reported. We obtained magnetic resonance imaging (MRI) scans for 21 autistic children and compared them with 21 control MRI scans. The areas of the brain stem and cerebellar vermis were measured using midsagittal images. The brain stem and cerebellar vermis lobules VIII to X were found to be significantly smaller in autistic children. A positive correlation between the size of the brain stem and cerebellar vermis was observed in the autistic children. This correlation was not observed in the control children. This suggests that the size of the brain stem and cerebellar vermis are anatomically altered in autistic children and that growth of the brain stem and cerebellar vermis in autistic children is different from normal children.

Autistic Disorder↗
PubMed1993

Chemical blockage of cervical sympathetic trunks for facial palsy.

Impairment of microcirculation of the facial nerves is considered to play an important role in etiology of facial palsy, and the main emphasis of the conservative treatment is aimed at circulatory improvement. Therefore, at the pain clinic, improved blood flow to the facial nerve by chemical blockage of cervical sympathetic trunks (stellate ganglion block; SGB) is employed in treating patients with facial palsy. The circulatory effects of SGB were clinically determined in 20 patients with acute Bell's palsy, and the effects of chemical blockage of cervical sympathetic trunks on the tissue circulation of facial nerve were also experimentally evaluated in dogs. In the clinical study, the blood flow volume of the common carotid artery increased significantly in 5 minutes after SGB, and has reached its peak of 176.4% in 20 minutes. This significant increase continued up to 75 minutes. In the animal model experiments, the common carotid arterial blood flow volume increased immediately after performing experimental SGB with a peak rise of 143.5% in 15 minutes, and the significant increase continued up to 45 minutes. The blood flow volume in the facial nerve tissue also increased for 5 minutes with a peak rise of 115.2% in 20 minutes after SGB, and this significant increase persisted for up to 60 minutes. A marked increase was observed in the blood flow volume in the facial nerve tissue as well as through the common carotid artery. The circulatory improvement performed by SGB extended as far as the facial nerve itself. From the facts above mentioned, SGB is considered to be an extremely effective treatment for the Bell's palsy.

Adolescent↗