Biomedical subjects

K Takeda

Publications and source records attributed to K Takeda.

At least 883 records · Page 49Linked to original sources

PubMed1991

Measurement of human hair growth by optical microscopy and image analysis.

We have developed a quantitative method for measuring hair growth using optical microscopy and image analysis, and have used this to investigate the rate of growth in subjects with and without alopecia. The hairs were cut from an area 7-8 mm in diameter and 24 h and 72 h later, images of the areas were obtained using an optical microscope and were recorded on a video disc. Measurements of the regrowing hairs, placed parallel to the scalp using a glass slide attached to the front of the microscope, were made using the image analyser. In subjects with little or no baldness there was a clear difference between fast-growing hairs and resting or slow-growing hairs. However, in subjects with alopecia there was no such difference and the growth rate of all the hairs showed a continuous distribution. Using this method other parameters such as the number of hairs per unit area and hair diameter as well as grouping of the hairs could be measured.

Adult↗

PubMed1991

Recombinant interleukin-1 alpha inhibits the growth of rat mesangial cells in culture.

We have investigated the effect of interleukin-1 (IL-1) on the growth of mesangial cells isolated from rat kidney. Recombinant IL-1 alpha inhibited 3H-thymidine uptake by mesangial cells in a dose-dependent manner in the presence of either 0.5% or 5% fetal bovine serum (FBS). In the presence of high concentration of FBS (10%), the effect of IL-1 was not prominent. The inhibitory effect of IL-1 on the growth of mesangial cells was also confirmed by a change in cell numbers and measurements of protein synthesis with 3H-leucine. IL-1-induced inhibition of mesangial cell growth was not affected by indomethacin. IL-1 showed no effects on intracellular Ca2+ levels in mesangial cells. These observations indicate that IL-1 inhibits the growth of mesangial cells, and thus may play a protective role for mesangial cells from abnormal proliferation in some pathophysiological states.

Angiotensin II↗

PubMed1991

Characteristic distribution of alpha 2 wave in electroencephalograms of schizophrenic patients during discriminative tasks: support for the hypofrontality hypothesis of schizophrenia.

In a preliminary study, we noticed that alpha 2 activity in the frontal regions was suppressed less in schizophrenic patients than in other patients during the discriminative tasks. This was confirmed with 37 schizophrenic and 16 nonschizophrenic patients under the treatment of neuroleptics, 15 nonmedicated schizophrenic patients and 32 normal controls. The EEGs in eye-closed resting and during the auditory and visual discriminative tasks were recorded. Alpha 2 power values of the frontal, central, parietal, occipital and temporal regions in every subject group were processed by cluster analysis. During the discriminative tasks, the frontal regions were the most isolated cluster in schizophrenic patients and, in the normal and medicated nonschizophrenic groups, the frontal regions were incorporated in a different cluster. The same result was obtained by different statistical analyses of F-alpha 2 power ratio. The relative abundance of alpha 2 power value shifts from the occipital to the frontal regions during the discriminative tasks in schizophrenic patients. The weakened suppression of alpha 2 waves in the frontal regions by the discriminative tasks in schizophrenic patients supports the hypofrontal hypothesis of schizophrenia.

Adolescent↗

PubMed1991

Improved technique for identification and enumeration of methanogenic bacterial colonies on roll tubes by epifluorescence microscopy.

Methanogenic fluorescent colonies can be clearly identified on roll tubes by using an epifluorescence microscope equipped with a x 2 objective. Methanogenic and nonmethanogenic colonies could be counted in roll tubes prepared from methanogenic enrichment cultures. Late-developing colonies appearing after 25 days of incubation were mainly methanogenic.

Journal Article↗

PubMed1991

Nucleotide sequence and characterization of the sfs1 gene: sfs1 is involved in CRP*-dependent mal gene expression in Escherichia coli.

We have cloned at least 12 different Escherichia coli genes which enable strain MK2001 to use maltose. The genes were designated sfs1 through sfs12 (sugar fermentation stimulation). Previously, one (sfs7) of them was mapped at 65 min on the E. coli chromosome and identified as nlp, which has high homology to repressor protein (Ner) of Mu phage, which contains a putative DNA binding region (Y.-L. Choi, T. Nishida, M. Kawamukai, R. Utsumi, H. Sakai, and T. Komano, J. Bacteriol. 171:5222-5225, 1989). In this study, another gene (sfs1) located at 3.5 min was newly found and analyzed. The nucleotide sequence of sfs1 encoded a protein of 234 amino acids (molecular mass, 26,227 Da) which also has a putative DNA binding domain. Overexpression of the sfs1 gene in MK2001 resulted in a 10-fold increase of amylomaltase, which was still dependent on MalT. These results suggest that Sfs1 could be a new regulatory factor involved in maltose metabolism.

Amino Acid Sequence↗

PubMed1991

Adult and neonatal human brain: diffusional anisotropy and myelination with diffusion-weighted MR imaging.

Diffusional anisotropy of human brain was investigated clinically in six adult volunteers, eight premature neonates, and three infants aged 5-10 months. Diffusion-weighted magnetic resonance imaging was performed with gradient b of 450 sec/mm2. The direction of diffusion-sensitive gradients was changed among x, y, and z axes according to the orientation of neurofibers in white matter. T1- and T2-weighted images also were obtained for evaluation of myelination. Diffusional anisotropy was demonstrated in white matter in the adults. Extensive signal attenuation was observed when gradients were parallel to white matter fibers. Conversely, in neonates, diffusional anisotropy of white matter, in which no myelination was shown on T1- and T2-weighted images, was weak. Diffusional anisotropy was more distinct after brain maturation, as observed in adult white matter. Detection of diffusional anisotropy is useful in evaluating neonatal brain development and various white matter disorders.

Adult↗

PubMed1991

Slope of human left ventricular end-systolic force-length relation is independent of myocardial length.

We have introduced a new contractility index (Ec), i.e., the slope of the left ventricular (LV) end-systolic force-length (Fes-Les) relation. To examine whether Ec was dependent on the LV wall myocardial length, 16 normal hearts of human subjects were evaluated to determine the LV end-systolic force-dimension (Fes-Des) and pressure-dimension (Pes-Des) relations (dimension denotes the distance between the LV septum and posterior wall). LV end-systolic pressures and dimensions were estimated simultaneously by intra-arterial cannulation and LV echocardiography. In seven subjects, the effect of a dobutamine infusion was also assessed. The Fes-Des relation was found to be nearly linear. Slopes and extrapolated dimension intercepts were obtained for the LV Fes-Des and Pes-Des relations [Ec, slope of LV Pes-Des relation (Es), and extrapolated dimension intercept of LV Fes-Des (Do), and of Pes-Des relation (D'o), respectively]. Es showed a hyperbolic relation to the baseline LV Des, whereas Ec was unrelated to it. The average variation for Ec (9.5%) was smaller than that for Es (22.5%). Dobutamine infusion increased Ec, Es, and D'o, whereas Do was not changed. Thus the assumption of linearity of the LV Fes-Les relation was found to be reasonable in normal human hearts. Do appears to provide a more accurate parameter than D'o for estimating the actual unstressed myocardial length, whereas Ec could possibly serve as an index of LV wall performance in the normal human heart that is independent of myocardial length and nearly constant between individuals.

Adult↗

PubMed1991

Time-varying myocardial elastance of canine left ventricle.

A formula was derived from an active cross-bridge model for expressing the "time-varying myocardial elastance" of the left ventricular (LV) wall. To assess the validity of this model's predictions of the behavior of the intact left ventricle, eight healthy beagles were instrumented with ultrasonic crystals to measure LV diameter and a micromanometer for LV pressure measurement. During ejecting beats starting from short end-diastolic myocardial lengths, the predicted values for myocardial elastance and force closely approximated the measured values for the instantaneous external load-muscle length ratio and the external load, respectively. However, in cycles starting from long end-diastolic lengths, the predicted myocardial elastance and force values deviated from the actual values during the shortening phase of LV contraction. The differences between myocardial elastance and external load-muscle length ratio as well as those between force and external load during the shortening phase (shortening deactivation) appeared to result from an internal load in the shortening myocardium that was closely related to the product of instantaneous myocardial force and shortening velocity. Thus this model may provide reasonable approximations of myocardial elastance and force in the intact LV wall. In addition, time-varying myocardial elastance might reflect time-dependent changes in calcium activation.

Animals↗

PubMed1991

Responses of baboons to prolonged hyperoxia: physiology and qualitative pathology.

Cardiopulmonary responses to prolonged hyperoxia and their relationships to the development of lung pathology have not been fully characterized in primates. In this study, circulatory hemodynamics and pulmonary function, vascular permeability, and leukocyte sequestration were measured in male baboons after 100% O2 exposure and related to ultrastructural changes of lung injury by electron microscopy. Three groups of animals were exposed to 100% O2 in an exposure cage for 40, 66, and 80 h, respectively. A fourth group of animals was exposed in a cage for 80 h and then anesthetized and ventilated with 100% O2 for additional time. These animals were exposed for a total duration of 110 h or until death from the injury. Physiological responses to hyperoxia were characterized by decreases in total lung capacity and inspiratory capacity at 80 and 110 h. A significant increase in pulmonary leukocyte accumulation was noted by 80 h. Extravascular lung water and permeability surface-area product increased at 80 and 110 h. Cardiac output and stroke volume also decreased, and systemic vascular resistance increased after 80 and 110 h of hyperoxia. Histopathological changes were present in the lungs of all but the 40-h exposure group. Animals exposed for 66 h showed endothelial injury and neutrophil accumulation. By 80 h, animals showed endothelial cell destruction, interstitial edema, and type I cell injury. At 110 h, animals showed substantial destruction of endothelial and type I epithelial cells, exposure of alveolar basement membrane, congestion of capillaries, and substantial interstitial edema. The data indicate that histological changes by electron microscopy precede physiological responses to hyperoxic pulmonary injury in baboons by as much as 14 h and that the physiological responses to early hyperoxic injury are relatively insensitive to the pathological injury.

Animals↗

PubMed1991

Screening of nineteen unrelated families with generalized resistance to thyroid hormone for known point mutations in the thyroid hormone receptor beta gene and the detection of a new mutation.

Generalized resistance to thyroid hormone (GRTH) is a syndrome characterized by impaired tissue responsiveness to thyroid hormone. Two distinct point mutations in the hormone binding domain of the thyroid hormone receptor (TR) beta have recently been identified in two unrelated families with GRTH. One, Mf, involves a replacement of the normal glycine-345 for arginine in exon 7 and another, Mh, replaces the normal proline-453 for histidine in exon 8. To probe for the presence of the Mf and Mh defect in 19 unrelated families with GRTH, we applied separate polymerase chain reactions using allele-specific oligonucleotide primers containing the normal and each of the two mutant nucleotides at the 3'-position. A total of 24 affected subjects and 13 normal family members were studied. The mode of inheritance was dominant in 13 families, was unknown in 5 families, and was clearly recessive in 1 family in which only the consanguineous subjects were affected. Primers containing the substitutions specific for Mf and Mh amplified exons 7 and 8, respectively, only in affected members of each of the two index families. Primers containing the normal sequences amplified exons 7 and 8 of the TR beta gene in all subjects except affected members of one family. In this family with recessively inherited GRTH, neither exon could be amplified using any combinations of primers and DNA blot revealed absence of all coding exons. These results indicate a major deletion of the TR beta gene, including both DNA and hormone binding domains. Since heterozygous members of this family are not affected, the presence of a single normal allele is sufficient for normal function of the TR beta. These data also support the hypothesis that in the dominant mode of GRTH inheritance the presence of an abnormal TR beta interferes with the function of the normal TR beta. Distinct mutations are probably responsible for GRTH in unrelated families.

Alleles↗

PubMed1991

Incidence of aneurysms in Takayasu's arteritis.

The angiographic findings of Takayasu's arteritis in a series of 113 patients were reviewed. Predominant findings were stenotic or occlusive changes, but fusiform or saccular aneurysms were also found in 36 patients (31.9%) in the various sites of aorta and its major branches. Multiple aneurysms were found in 15 patients. The most common site of aneurysms was the ascending aorta (16 patients); in 7 of the patients these were complicated by aortic regurgitation. Aneurysms developed in the aortic arch in 3 patients, in the descending aorta in 11, in the abdominal aorta in 7, and in the major branches of the aortic arch in 9 patients. In 2 patients, follow-up angiograms showed enlargement of the aneurysms, and rupture of the aneurysm occurred in 1 patient. Aneurysms were found even in young patients. A fifteen-year-old female showed a huge aneurysm in the ascending aorta as the initial manifestation of this disease. Thickening of the walls of aneurysms was common and characteristic. This study revealed the moderately high incidence of aneurysms of various sites of arteries in patients with Takayasu's arteritis. The authors conclude that aneurysm, as well as occlusive changes, can be a primary lesion.

Adolescent↗

PubMed1991

Double aortic arch associated with coarctation of both limbs: a case report.

A case of double aortic arch with coarctation of both limbs is described. The patient, a thirteen-year-old girl, demonstrated only the symptoms of coarctation and had no intracardiac anomalies. Discrete coarctation of bilateral limbs distal to the subclavian artery was shown by aortography. Although either double aortic arch or coarctation of the aorta is not so rare, the combination of these two anomalies is quite unusual. This is the third case in the world literature.

Abnormalities, Multiple↗

PubMed1991

Elevated activity of low molecular weight insulin-like growth factor-binding proteins in sera of vitamin C-deficient and fasted guinea pigs.

We have previously reported that scorbutic and fasted guinea pig sera contain an insulin-like growth factor-I (IGF-I)-reversible inhibitor of collagen, proteoglycan, and DNA synthesis in cultured cells. Here we report that IGF-binding protein (IGFBP) activity is increased in serum containing the inhibitor [125I]IGF-I or -II bound to these sera was eluted in the 30- to 50-kDa region of an S200 gel column. [125I]IGF-I affinity cross-linking analysis revealed that a 38-kDa cross-linked species increased markedly in fasted and scorbutic sera, with a lesser increase in a 34-kDa species, while scorbutic sera also yielded a 44-kDa species. Gel filtration of unlabeled sera showed a 10-fold increase in the activity of two proteins in the 30- to 50-kDa region from the experimental sera. Their activity correlated with their ability to inhibit binding of [125I]IGF-I to its cellular receptor, suggesting that they have the potential to inhibit IGF-I-dependent functions. Ligand blotting showed that 29 and 35-kDa IGFBPs were almost undetectable in normal serum, but were dramatically induced by scurvy and fasting, so that they accounted for close to 40% of the total circulating BPs. Total IGFBP-3 in the experimental sera was increased about 30%, while there was little effect of scurvy or fasting on the level of BP-3 activity isolated by acid extraction of the high mol wt region of the S200 column. An IGF-I analog with normal affinity for the 30- to 50-kDa BPs from fasted and scorbutic sera, but with reduced affinity for the cell receptor, was equivalent to IGF-I in reversing the inhibition of collagen synthesis by scorbutic guinea pig serum in human fibroblasts. Thus, reversal of inhibition appears to require initial saturation of IGFBPs. The overall results suggest that two circulating IGFBPs with unoccupied binding sites are induced in vitamin C-deficient or fasted guinea pigs and may be responsible for inhibition of IGF-I-dependent functions by sera from these animals.

Animals↗

PubMed1991

Enhanced norepinephrine release in hypothalamus from locus coeruleus in SHR.

The hypothesis that a functional projection from the locus coeruleus (LC) to the posterior hypothalamus contributes to the development of hypertension in SHR, was tested by measuring norepinephrine (NE) in the posterior hypothalamus by brain dialysis after injections of L-glutamate (L-glu) into LC. L-glu elicited a prolonged elevation of blood pressure in both SHR and WKY. Pressor effects were significantly larger in SHR than in WKY. Extracellular NE in the posterior hypothalamus increased after LC stimulation; NE release was significantly higher in SHR than in WKY. Injections of 6-hydroxydopamine (6-OHDA) into posterior hypothalamus lowered the resting blood pressure and attenuated the pressor responses to L-glu injections into the LC in SHR. These findings suggest that the LC projects functionally to the posterior hypothalamus and that the projection can contribute to the development of hypertension in SHR.

Animals↗

PubMed1991

Cross-bridge cycling energy of cardiac muscle estimated from an active cross-bridge model.

A mathematical formula was derived from an active cross-bridge model to express the changes in the active myocardial force which occurred during systole. Using the formula and the assumption that the energy expenditure for cross-bridge cycling (Um) was a linear function of the force-time integral (FTI), we developed formulae describing the left ventricular Um versus FTI relation, the Um versus force relation, and the Um versus pressure-volume area (PVA) relation. There were strong disagreements between the model predictions and the experimental findings relating oxygen consumption of the heart versus the PVA relation. These differences may have resulted from the oversimplification of important mechanical and/or biochemical properties of the myocardium in the model. However, the model appeared to accurately reproduce the Fenn effect (effect of contraction modes on energy liberation) for the myocardium as well as the effect of catecholamine infusion, hypothermia, and hypothyroidism on the changes in the binding rate of Ca2+ with the regulatory proteins, the myosin ATPase activity, the peak force developed, and the myocardial energy expenditure. We present this work as an intermediate step towards a complete theoretical linkage between the molecular biology, dynamics, and energetics of the human heart.

Biomechanical Phenomena↗

PubMed1991

Afterloading increases the left ventricular end-systolic force-length relation slope in dogs.

We evaluated the effects of pressure loading produced by gradual aortic occlusion on left ventricular (LV) myocardial contractility by assessing changes in the slope of the LV end-systolic force-diameter (Fes-Des) relation. Eleven adult mongrel dogs were prepared with ultrasonic crystals for measuring LV diameter and a micromanometer for measuring LV pressure. Preload was decreased by vena caval occlusion (VCO), and afterload was increased by aortic occlusion (AOO). The slopes (Ec) and extrapolated diameter intercepts (Do) of the LV Fes-Des relation were determined for each dog from the end-systolic data obtained during VCO and AOO. During VCO and also AOO, the heart rate showed little change (134 +/- 18 vs. 134 +/- 16 bpm in VCO, 135 +/- 16 vs. 132 +/- 17 bpm in AOO). The values of Ec and Do during VCO were 62.8 +/- 15.6 g/cm and 1.20 +/- 0.36 cm, respectively, while during AOO the respective values were 122.6 +/- 18.6 g/cm and 1.66 +/- 0.38 cm. Ec and Do were both significantly increased during AOO in comparison with VCO (p less than 0.001). These results suggest that gradual aortic occlusion increases LV myocardial contractility in anesthetized, open-chest dogs under autonomic blockade. This phenomenon might be related to length-dependent calcium activation.

Animals↗

PubMed1991

Initial pathophysiological changes in chronic pancreatitis induced by pancreatic ductular obstruction model.

An experimental chronic pancreatitis model was made in five dogs with chronic pancreatic fistula by injection of microspheres into the peripheral pancreatic duct. Sequential changes of pancreatic exocrine and endocrine functions with morphology were studied. Significant decreases in volume bicarbonate output and amylase output were detected in each sample collected separately on secretin and secretin cerulean stimulation. While the viscosity of pancreatic juice was significantly increased with a concomitant increase in hexosamine concentration, chronic pancreatitis was demonstrated morphologically. These results suggest that concentrated pancreatic juice caused by a decrease in volume and an increase in viscosity of pancreatic juice with a concomitant increase in hexosamine concentration brings about the progression of chronic pancreatitis in this experimental model.

Amylases↗

PubMed1991

Changes of duodenal pH and pancreatic exocrine function after upper G-I intraluminal ethanol administration.

Using 3 outbred dogs with pancreatic, gastric and jejunal fistulas, we examined changes in pancreatic exocrine secretion, duodenal pH and plasma CCK concentration after intragastric or intrajejunal administration of ethanol. Intragastric administration of 20% or 40% ethanol significantly lowered the pH in the duodenal cavity, and pancreatic fluid secretion and bicarbonate excretion were stimulated. Intrajejunal administration of ethanol elicited stronger responses. Plasma CCK concentration was not changed or was only slightly lowered by ethanol administration in the digestive tract. It is assumed that stimulation of pancreatic exocrine secretion was mediated by the secretion of gastric acid.

Animals↗