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Biomedical subjects

H Takano

Publications and source records attributed to H Takano.

At least 325 records · Page 18Linked to original sources
PubMed1995

Interferon-alpha-induced apoptosis in human erythroid progenitors.

Recombinant human interferon-alpha (rIFN-alpha) inhibits erythropoiesis, in vivo and in vitro. In an attempt to clarify mechanisms related to this inhibition, effects of rIFN-alpha on highly purified human peripheral blood burst-forming units-erythroid (BFU-E) (20-60% purity) were compared with effects on erythroid progenitors in various stages of development. Day-1 and -7 cultured cells were equivalent to primitive BFU-E and colony-forming units-erythroid (CFU-E), respectively. Day-1 BFU-E supported by recombinant human erythropoietin (rEpo) and interleukin-3 (rIL-3) was inhibited by rIFN-alpha in a dose-dependent manner, and a significant inhibition occurred at 2000 U/mL rIFN-alpha. Limiting dilution analysis demonstrated that rIFN-alpha directly inhibits BFU-E rIFN-alpha inhibited the proliferative capacity or the colony expression of erythroid progenitors, with no relation to the stage of development, but inhibition of differentiation was not apparent. This evidence suggested that apoptosis of erythroid progenitors was induced by IFN-alpha. When day-7 cells were incubated with IFN-alpha in the presence of rEpo, there was an increased breakdown of total cellular DNA into DNA fragments of less than 5 kb; hence, the inhibitory effect of IFN-alpha on erythroid progenitors may mediate apoptosis.

Adult↗
PubMed1995

Dentatorubral-pallidoluysian atrophy (DRPLA). Molecular basis for wide clinical features of DRPLA.

Dentatorubral-pallidoluysian atrophy (DRPLA) is a rare autosomal dominant neurodegenerative disorder characterized clinically by various combinations of myoclonus, epilepsy, cerebellar ataxia, choreoathetosis, dementia and psychiatric symptoms. Based on the phenomenon of anticipation, the gene for DRPLA was recently identified. DRPLA is caused by unstable expansion of a CAG repeat in the gene located on the short arm of chromosome 12. As have been observed in Huntington's disease and SCA1, there is a strong correlation between the age of onset and the size of CAG repeats. Furthermore, patients with larger repeats tend to show a PME (progressive myoclonus epilepsy) phenotype as well as earlier ages of onset. More prominent anticipation and larger intergenerational increase of CAG repeats in paternal transmission can be accounted for by the meiotic instability of CAG repeats in male gametogenesis. Comparison of size distributions of CAG repeats in Japanese, African-American and white populations revealed that 7.4% of the Japanese alleles had greater than 19 repeats, whereas none of the whites and 1% of the African-American alleles were of this size. The results may account for the ethnic predilection of DRPLA.

Adult↗
PubMed1995

Parameters of dynamic and static iodine-123-MIBG cardiac imaging.

UNLABELLED: Dynamic and static 123I-MIBG studies were used to investigate various parameters with regard to their usefulness in evaluating cardiac disorders. METHODS: Four patient groups and one control group were included in this study. Dynamic study was acquired immediately after injection at 1 frame/sec for 2 min and at 1 frame/6 sec for the next 30 min using a 64 x 64 matrix format. Static study consisted of planar images at the anterior and left anterior oblique 45 degrees views in a 512 x 512 matrix format for 1 min. The early and delayed planar images were acquired soon after dynamic acquisition and approximately 4 hr after injection, respectively. Net injection dose was calculated as the difference in syringe counts before and after injection. From the dynamic and static studies, the heart uptake ratios at 3 min and 30 min, early uptake ratio and delayed uptake ratio were calculated at various intervals. Early and delayed clearance rates, Ke and Kd, respectively were also determined. These parameters were compared and correlated with each other. RESULTS: Three-minute heart uptake ratios were significantly higher than early or delayed uptake ratios or uptake ratios at 30 min in all groups. All uptake ratios in hemodialysis patients were significantly higher than those in other groups. The Kd values in dilated cardiomyopathy, doxorubicin therapy and vasospastic angina patients were significantly higher than those in hemodialysis patients and normal controls. At least bi-exponential clearance patterns of MIBG from the heart were observed in all groups. CONCLUSION: Three-minute and delayed heart uptake ratios calculated from dynamic and static studies are helpful in elucidating the uptake at nonvesicular sites, which reflect the severity of sympathetic nervous system abnormalities in the heart.

3-Iodobenzylguanidine↗
PubMed1995

Radiological changes of frontometaphyseal dysplasia in the neonate.

The radiological manifestation of frontometaphyseal dysplasia has been well elucidated in later childhood and adulthood, but it has not been thoroughly clarified in the neonate. Here we report the radiological features of a neonate with frontometaphyseal dysplasia. Most features, including twisted ribs, increased interpediculate distances of the lumbar spine, flared ilia, mildly flared and bowed long bones, and arachnodactyly with undermodeled short tubular bones, were reminiscent of those found in older children and adults. A previously undescribed abnormality was advanced ossification of the femoral and tibial epiphyses.

Abnormalities, Multiple↗
PubMed1995

[Experience and problems with home parenteral nutrition for patients with peritonitis carcinomatosa].

Since 1987, we have been using home parenteral nutrition (HPN) for patients with peritonitis carcinomatosa, who had undergone surgery for cancer of the digestive tract and who could not take food orally. We have been inserted catheterization for HPN in 90 patients. Nine of them underwent the treatment as training, but HPN was possible in the remaining 81 patients (90%). The patients in whom the treatment failed to be transferred to HPN showed worsening of their general condition during hospitalization, because the period of training was long. As a result, they could not be discharge. We considered that the timing of transfer to HPN was inappropriate. The largest number of patients, 57, had undergone surgery for cancer of the stomach and esophagus, which was the underlying disease. The mean period of HPN was 108.2 days. According to the underlying disease, the period was longest, 115.7 days, for cancer of the stomach and esophagus, followed by 93.8 days for colorectal cancer. The performed rate of HPN for 60, 90, 180 and 270 days were 56.7, 36.0, 17.9 and 6.5%, respectively, with the one-year cumulative rate of 3.3%. HPN for terminal stage of cancer is an effective treatment for patients with peritonitis carcinomatosa, and it allowed improvement in the quality of life. Cooperation with various medical staff members is also necessary and a hospital system should be established for safe and smooth achievement of the treatment method.

Ascitic Fluid↗
PubMed1994

Excitation-contraction uncoupling and muscular degeneration in mice lacking functional skeletal muscle ryanodine-receptor gene.

Contraction of skeletal muscle is triggered by the release of Ca2+ from the sarcoplasmic reticulum (SR) after depolarization of transverse tubules. The ryanodine receptor exists as a 'foot' protein in the junctional gap between the sarcoplasmic reticulum and the transverse tubule in skeletal muscle, and is proposed to function as a calcium-release channel during excitation-contraction (E-C) coupling. Previous complementary DNA-cloning studies have defined three distinct subtypes of the ryanodine receptor in mammalian tissues, namely skeletal muscle, cardiac and brain types. We report here mice with a targeted mutation in the skeletal muscle ryanodine receptor gene. Mice homozygous for the mutation die perinatally with gross abnormalities of the skeletal muscle. The contractile response to electrical stimulation under physiological conditions is totally abolished in the mutant muscle, although ryanodine receptors other than the skeletal-muscle type seem to exist because the response to caffeine is retained. Our results show that the skeletal muscle ryanodine receptor is essential for both muscular maturation and E-C coupling, and also imply that the function of the skeletal muscle ryanodine receptor during E-C coupling cannot be substituted by other subtypes of the receptor.

Animals↗
PubMed1994

Effects of systemic or spinal cord cooling on conductive spinal evoked potentials.

To elucidate the mechanism of alterations of spinal evoked potentials after hypothermia, the effects of systemic and local cooling on conductive spinal evoked potentials were studied in cats. Conductive spinal evoked potentials were recorded from the L1 epidural space after epidural stimulation at the T4 level and during concomitant reduction of body temperature followed by rewarming. On local cooling and rewarming of the stimulating area or the recording area, conductive spinal evoked potentials changes were also analyzed. Systemic cooling provoked an increase in latency, duration, and amplitude as the body temperature decreased. Evoked potentials were not changed by the local cooling of the stimulating area. Thus, the evoked potentials changes of the spinal cord suggest that spinal cord cooling does not influence the stimulus threshold, but may affect the interaction between the amplitude change and the duration in individual spike potentials, and produces changes in temporal dispersion.

Animals↗
PubMed1994

Complex terminal structure of a linear mitochondrial plasmid from Physarum polycephalum: three terminal inverted repeats and an ORF encoding DNA polymerase.

The mitochondria of Physarum polycephalum have a linear plasmid (mF) which promotes mitochondrial fusion. To determine the terminal structure of the mF plasmid, restriction fragments derived from its ends were cloned and sequenced. The sequences showed that the mF plasmid has three kinds of terminal inverted repeats (TIRs). The most characteristic feature is a 144-bp repeating unit which exists between a 205-bp TIR at the extreme ends of the plasmid and another 591-bp TIR. All of the clones showed at least one of these 144-bp repeating units. The GC content of the 205-bp TIR (49%) was higher than those of the other TIRs and of another sequenced region (23%). This TIR can form three thermodynamically-stable hairpin structures based on complex internal palindromic components. Moreover, in the right terminal region of the mF plasmid, there is an open reading frame (ORF) which covers the entire 591-bp TIR and most of one of the 144-bp repeating units. This ORF encodes a 547-amino-acid polypeptide, ORF-547, and shows extensive homology with the polymerization domain of the putative DNA polymerases of linear mitochondrial plasmids from other sources.

Amino Acid Sequence↗
PubMed1994

Detection of human cytomegalovirus DNA in dried newborn blood filter paper.

To detect human cytomegalovirus (HCMV) DNA, filter paper spotted with peripheral blood from newborns 4 to 7 days after birth was dried and subjected to the polymerase chain reaction (PCR) followed by Southern blot hybridization with a nonradioactive oligonucleotide probe. The detection rates were 25.1% in healthy individuals and 33.0% in low body weight neonates weighing not more than 2500 g at birth, most of whom appeared to have been infected transplacentally or by other means within the uterus. HCMV was detected after only heating the dried blood on the filter paper, and may be applied as a screening method for the early diagnosis of HCMV.

Adult↗
PubMed1994

Monitoring for spinal cord ischemia by use of the evoked spinal cord potentials during aortic aneurysm surgery.

PURPOSE: This clinical study was to evaluate changes of evoked spinal cord potentials (ESCPs) elicited by direct spinal cord stimulation and to determine their relation to spinal cord ischemia during aortic aneurysm surgery. METHODS: We monitored descending ESCPs from the thoracic spinal cord and lumbar enlargement after cervical spinal cord stimulation (thoracic descending ESCP and lumbar descending ESCP), and segmental ESCP at lumbar enlargement elicited by bilateral tibial nerve stimulation in 22 aortic aneurysm surgical operations. RESULTS: ESCP changes were classified into three types: (1) decrease of amplitude in lumbar descending ESCP and segmental ESCP; (2) decrease of amplitude in segmental ESCP alone; (3) decrease of amplitude in all ESCPs. The late negative waves of both lumbar descending ESCP and segmental ESCP were more sensitive than other components of ESCPs. Postoperative paraplegia occurred in the two cases that showed persistent diminution of amplitude in the late negative waves. Segmental ESCP was less reliable than lumbar descending ESCP, because it depended entirely on the adequate perfusion of the lower extremities. CONCLUSIONS: Lumbar descending ESCP was the best method for the spinal cord ischemia during aortic aneurysm surgery. Spinal cord ischemia could be detected by diminution in the amplitude of the late negative wave of lumbar descending ESCP. The recovery amplitude of the late negative wave after declamping correlated with the neurologic outcome.

Aged↗
PubMed1994

Novel method to determine instantaneous blood volume in pulsatile blood pump using electrical impedance.

A novel real-time volumetric method was developed for a pulsatile pump. This method, the impedance method, used electrical impedance change in the blood chamber according to volume change while pumping. This method was evaluated with two kinds of air-driven diaphragm pumps. During in vitro tests, the impedance method indicated real-time volume change, and there was excellent correlation between computed stroke volume with the impedance method and measured stroke volume with the electromagnetic flowmeter. In chronic animal tests with goats and in a clinical case, the impedance method measured pump output accurately, and it detected diaphragm motion in real-time. In addition, excellent durability was seen. Full-fill to full-empty drive was realized accurately with this method. Application of the impedance method was easy, and it did not deteriorate native antithrombogencity of the pump. The impedance method is practical and useful to estimate the pumping condition of a pulsatile blood pump, especially a diaphragm pump. This method would be useful in clinical application.

Aged↗
PubMed1994

Colonic submucosal tumors: comparison of endoscopic US and target air-enema CT with barium enema study and colonoscopy.

PURPOSE: To compare the imaging characteristics of colonic submucosal tumors at endoscopic ultrasound (US) and target air-enema computed tomography (TACT) with those at conventional double-contrast barium enema study and colonoscopy. MATERIALS AND METHODS: Twenty consecutive patients with suspected colonic submucosal tumors at barium enema study and colonoscopy underwent endoscopic US, TACT, or both. Morphologic features and posture-related change in shape of tumor were evaluated with barium enema study, color and consistency of tumor with colonoscopy, internal echogenicity of tumor and layer of origin in normal colonic wall with endoscopic US, and CT attenuation number with TACT. RESULTS: Eight lipomas, seven carcinoids, three leiomyomas, four lymphangiomas, and one hemangioma were found at histologic examination. Lipomas and lymphangiomas had characteristic findings at endoscopic US and TACT. The differential diagnosis of the other submucosal tumors was facilitated by using endoscopic US. CONCLUSION: Endoscopic US and TACT may play a valuable role in the evaluation of colonic submucosal tumors.

Adult↗