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Biomedical subjects

K Takata

Publications and source records attributed to K Takata.

At least 127 records · Page 7Linked to original sources
PubMed1994

Cyclic sciatica. A case report.

We report a case of endometrioma in the pelvic cavity. A 41-year-old woman presented with a peculiar periodic sciatica associated with her menses. Computed tomography showed an oval-shaped mass in the pelvic cavity compressing the right sciatic nerve. To confirm the diagnosis, hormonal therapy through nose dropping of buserelin acetate was given to stop menstruation. After treatment, her symptoms disappeared completely. When a sciatica is closely related to menses, orthopedic surgeons should consider cyclic sciatica resulting from endometrioma as a differential diagnosis.

Adult↗
PubMed1994

Lectin binding pattern in normal human labial mucosa.

The pattern of lectin binding in normal human labial mucosa was examined by light and electron microscopy using eight different lectins (ConA, LCA, WGA, UEA-1, RCA-1, SBA, DBA and PNA) and compared with the patterns in normal human skin and oesophageal mucosa. As seen by light microscopy, ConA, LCA, and WGA stained cell membranes in all layers of the mucosae. RCA-1 stained the plasma membrane of cells in the basal and middle layers, whereas cells in the superficial layers showed little positive staining. UEA-1, SBA, and PNA stained the cells in the middle layers weakly in some cases. No positive staining for DBA was seen. By electron microscopy, reaction product indicating ConA-binding sites was observed in the plasma membrane, cisternae of the endoplasmic reticulum, nuclear envelope and the Golgi apparatus. Binding of LCA, WGA, and RCA-1 was observed in the plasma membrane. These results show that the binding pattern of PNA, SBA, and RCA-1 in labial mucosa is different from that in the normal skin or oesophageal mucosa, although the labial mucosal epithelium, epidermis, and oesophageal epithelium are all stratified squamous epithelia. These differences in the cell-surface sugar residues are likely to be related to the possible functional differences in these tissues.

Adult↗
PubMed1994

Immunolocalization of glucose transporter GLUT1 in the rat placental barrier: possible role of GLUT1 and the gap junction in the transport of glucose across the placental barrier.

GLUT1 is an isoform of facilitated-diffusion glucose transporters and has been shown to be abundant in cells of blood-tissue barriers. Using antibodies against GLUT1, we investigated the immunohistochemical localization of GLUT1 in the rat placenta. Rat placenta is of the hemotrichorial type. Three cell layers (from the maternal blood side inward) cytotrophoblast and syncytiotrophoblasts I and II, lie between the maternal and fetal bloodstreams. GLUT1 was abundant along the invaginating plasma membrane facing the cytotrophoblast and the syncytiotrophoblast I. Also, the infolded basal plasma membrane of the syncytiotrophoblast II was rich in GLUT1. Apposing plasma membranes of syncytiotrophoblasts I and II, however, had only a small amount of GLUT1. Numerous gap junctions were seen between syncytiotrophoblasts I and II. Taking into account the localization of GLUT1 and the gap junctions, we suggest a possible major transport route of glucose across the placental barrier, as follows: glucose in the maternal blood passes freely through pores of the cytotrophoblast. Glucose is then transported into the cytoplasm of the syncytiotrophoblast I via GLUT1. Glucose enters the syncytiotrophoblast II through the gap junctions. Finally glucose leaves the syncytiotrophoblast II via GLUT1 and enters the fetal blood through pores of the endothelial cells.

Animals↗
PubMed1994

A large painful Schmorl's node: a case report.

A 27-year-old woman presented with a 2-week history of low back pain and an unusually large Schmorl's node in the third lumbar vertebra. She reported no previous low back symptoms. Initially, a malignant spinal tumor was suspected because of the irregular osteolytic changes on the computed tomograms and high uptake with technetium bone mineral scanning. The lesion was subsequently diagnosed by discography as a Schmorl's node. The patient has now been followed for 3 years. At the time of this writing, she has been without low back symptoms or signs. Using serial computed tomography, we observed morphological changes in the Schmorl's node that were similar to those processes observed with fracture healing.

Adult↗
PubMed1994

Effects of respiratory interval on vagal modulation of heart rate.

To determine whether paced breathing (PB) and respiratory interval of PB modify the relationship between spectral components of heart rate variability (HRV) and cardiac vagal tone, we studied seven healthy young males under the condition of beta-adrenergic blockade by intravenous propranolol (0.2 mg/kg). Compared with spontaneous breathing, PB at the same respiratory interval as that of individual spontaneous breathing showed no significant effect on the amplitude of the high-frequency (HF) component or the mean R-R interval in either the supine or tilt position, whereas the PB decreased the amplitude of the low-frequency (LF; 0.04-0.15 Hz) component in both positions (P = 0.004 and 0.042, respectively). When the respiratory interval was increased from 3 to 6 s, the HF amplitude showed a progressive increase in both positions (P = 0.001 and 0.035, respectively), while the LF amplitude and mean R-R interval remained unchanged. These results indicate that the effects of PB and respiratory interval on the spectral components of HRV are not mediated by the changes in mean cardiac vagal tone and support the hypothesis that increased respiratory interval amplifies the respiratory-related vagal modulation of heart rate.

Adrenergic beta-Antagonists↗
PubMed1994

Assessment of frequency shifts in R-R interval variability and respiration with complex demodulation.

A complex demodulation (CDM) method for continuous assessment of frequency shifts and time-dependent changes in amplitude in the rhythmic components existing in predefined frequency bands was proposed and applied to the analysis of high-frequency (HF) and low-frequency (LF) components of the R-R interval and to the analysis of respiration via impedance spirogram. Simulation studies revealed that this CDM technique furnishes mathematical features well suited to the investigation of non-stationary R-R interval signals and can delineate time-dependent fluctuations in both amplitude and frequency, accurately differentiating between HF and LF components. Analysis of data during paced breathing at different respiratory frequencies revealed that the estimated frequency of the HF component and respiration faithfully reflected the frequency of paced breathing. Analysis of data during dynamic exercise with increasing workload (20 W/min) showed that the frequency of the HF component was elevated with exercise and that both HF and LF amplitudes were reduced progressively with advancing load. CDM-derived frequency and amplitude of respiration were highly correlated to direct breath-by-breath respiratory frequency and tidal volume measurements. We conclude that this method could provide a powerful means for continuously assessing time-dependent changes in both cardiovascular and respiratory variations.

Adult↗
PubMed1994

Characterization of subspecies of apolipoprotein A-I-containing lipoprotein in homozygotes for familial lecithin:cholesterol acyltransferase deficiency.

We characterized the two species of lipoproteins containing apolipoprotein A-I (apoA-I), one containing only apoA-I (LpA-I) and the other containing apoA-I and apoA-II (LpA-I/A-II), in four homozygotes for familial lecithin: cholesterol acyltransferase (LCAT) deficiency. Two homozygotes lacked both LCAT mass and activity, whereas the other two had some residual LCAT mass and activity. In these patients, the amount of all apoA-I-containing lipoproteins was one fourth that of normal control subjects, and > 60% was LpA-I. The chemical composition of both LpA-I and LpA-I/A-II is characterized by markedly decreased ratios of neutral to polar lipids compared with those of normals and the sizes of LpA-I and LpA-I/A-II particles are shifted to smaller and larger diameter ranges when compared with those of normal particles. Changes in particle diameter are also reflected in slower electrophoretic mobilities of both LpA-I and LpA-I/A-II particles. All of these abnormalities were more evident in the two homozygotes who lacked LCAT activity. Incubation of LCAT-deficient plasma with LCAT markedly corrected the chemical and physical abnormalities in both LpA-I and LpA-I/A-II particles. These data, taken together, emphasize the importance of LCAT in modifying the chemical composition, size, and shape of LpA-I and LpA-I/A-II particles.

Adult↗
PubMed1994

Genetic cholesteryl ester transfer protein deficiency caused by two prevalent mutations as a major determinant of increased levels of high density lipoprotein cholesterol.

Genetic determinants of HDL cholesterol (HDL-C) levels in the general population are poorly understood. We previously described plasma cholesteryl ester transfer protein (CETP) deficiency due to an intron 14 G(+1)-to-A mutation(Int14 A) in several families with very high HDL-C levels in Japan. Subjects with HDL-C > or = 100 mg/dl (n = 130) were screened by PCR single strand conformational polymorphism analysis of the CETP gene. Two other mutations were identified by DNA sequencing or primer-mediated restriction map modification of PCR products: a novel intron 14 splice donor site mutation caused by a T insertion at position +3 from the exon14/intron14 boundary (Int14 T) and a missense mutation (Asp442 to Gly) within exon 15 (D442G). The Int14 T mutation was only found in one family. However, the D442G and Int14 A mutations were highly prevalent in subjects with HDL-C > or = 60 mg/dl, with combined allele frequencies of 9%, 12%, 21% and 43% for HDL-C 60-79, 80-99, 100-119, and > or = 120 mg/dl, respectively. Furthermore, prevalences of the D442G and Int14 A mutations were extremely high in a general sample of Japanese men (n = 236), with heterozygote frequencies of 7% and 2%, respectively. These two mutations accounted for about 10% of the total variance of HDL-C in this population. The phenotype in a genetic compound heterozygote (Int14 T and Int14 A) was similar to that of Int14 A homozygotes (no detectable CETP and markedly increased HDL-C), indicating that the Int14 T produces a null allele. In four D442G homozygotes, mean HDL-C levels (86 +/- 26 mg/dl) were lower than in Int14 A homozygotes (158 +/- 35 mg/dl), reflecting residual CETP activity in plasma. In 47 D442G heterozygotes, mean HDL-C levels were 91 +/- 23 mg/dl, similar to the level in D442G homozygotes, and significantly greater than mean HDL-C levels in Int14 A heterozygotes (69 +/- 15 mg/dl). Thus, the D442G mutation acts differently to the null mutations with weaker effects on HDL in the homozygous state and stronger effects in the heterozygotes, suggesting dominant expression of a partially defective allele. CETP deficiency, reflecting two prevalent mutations (D442G and Int14 A), is the first example of a genetic deficiency state which is sufficiently common to explain a significant fraction of the variation in HDL-C in the general population.

Adult↗
PubMed1994

Assessment of myocardial function during mechanical left ventricular support using serial echocardiography: a case report.

A 40-year-old man with valvular heart disease was successfully treated using a left ventricular assist device (LVAD) after open heart surgery. Echocardiography revealed left ventricular ejection fraction (LV-EF) at LVAD on/off: 23.4%/14.6% on the 4th, 23.8%/23.8% on the 5th, and 23.8%/26.8% on the 6th postoperative day (POD), respectively. The patient was weaned from LVAD on the 8th POD and discharged from the hospital on the 58th POD. The LV-EF improved to 54% 6 months after surgery and increased from 57% to 64% in response to exercise stress testing 1 year after surgery.

Adult↗
PubMed1994

Hamstring tightness and sciatica in young patients with disc herniation.

We evaluated the nerve roots of the cauda equina by CT myelography in 36 patients aged from 11 to 19 years with lumbar disc herniation. On straight-leg-raising tests, six younger patients had isolated hamstring tightness with no sciatica (group A) and 30 had sciatic pain (group B). CT myelography showed that no patient in group A had associated nerve-root swelling, and that the roots were displaced posteriorly, but not compressed. In 21 of the group-B patients, swelling of the nerve roots was confirmed, with compression between the herniated disc and the superior articular process. Our findings suggest that hamstring tightness in these patients may be caused by a different mechanism from that which causes sciatic pain.

Adolescent↗
PubMed1993

The role of N-glycosylation in the targeting and stability of GLUT1 glucose transporter.

The cDNAs encoding the GLUT1 glucose transporter protein were altered by site-directed mutagenesis at consensus sites for the addition of N-linked glycosylation. These cDNAs were transfected into CHO cells with an expression vector and the subcellular distribution and stability of the expressed glycosylation-defective GLUT1 protein were analyzed. Immunohistochemical analysis with a specific antibody demonstrated that a significant portion of glycosylation-defective GLUT1 protein remained in the intracellular compartment. By contrast, most of the wild-type GLUT1 protein expressed with the same procedures resided in the plasma membranes. Metabolic labeling studies revealed that the half-life of the glycosylation-defective GLUT1 protein was significantly shorter than that of wild-type GLUT1 protein. These results indicate that N-glycosylation of the glucose transporter affects its intracellular targeting and protein stability.

Animals↗
PubMed1993

Articular facets of the human spine. Quantitative three-dimensional anatomy.

This study provides the quantitative three-dimensional surface anatomy of the articular facets for the entire human vertebral column based on a study of 276 vertebrae. Means and standard errors of the means for linear, angular, and area dimensions of the superior and inferior articular facets were measured for all vertebrae from C2 to L5. Facet orientations were described as angles with respect to the sagittal and transverse planes and also as card angles. The plane angles are similar to the angles seen on traditional radiographic views--radiographs and computed tomographic scans. The card angles, a new concept, are better at helping visualize the three-dimensional orientations of the facets. Excluding the superior C2 facet, the following minimum and maximum dimensions were found for the facets from C3 to L5: width = 9.6-16.3 mm; height = 10.2-18.4; surface area = 72.3-211.9 mm2; interfacet width = 20.8-40.6; interfacet height = 12.2-33.0 mm; transverse plane angle = 41.0-86.0; sagittal plane angle = 67.4-154.8; X-card angle = 41.0-86.0; and Y-card angle = 5.8-66.1. The quantitative anatomy of the facets may improve the understanding of the spinal anatomy, help improve the clinical diagnosis and treatment, and provide the necessary data for constructing more realistic mathematical models of the spine.

Adult↗
PubMed1993

Continuous assessment of hemodynamic control by complex demodulation of cardiovascular variability.

Usefulness of complex demodulation (CDM) in assessing the frequency components of cardiovascular variability was assessed and, subsequently, this technique was utilized to determine the time-dependent responses of the low-frequency (LF) and high-frequency (HF) amplitudes of heart rate and blood pressure variabilities during postural tilt. CDM provides the time-dependent changes in amplitude of a particular frequency component on a continuous basis. Analysis of simulated data showed that CDM has sufficient frequency resolution to separately measure LF and HF amplitudes with a time resolution < 15 s and that CDM is robust to alterations in the frequency of the components. Analysis of actual data during postural tilt test in 23 young healthy subjects demonstrated that the HF amplitude of heart rate, an index of cardiac parasympathetic tone, rapidly decayed with head-up tilt (P < 0.01) and increased quickly showing an overshoot with tilt back to the supine position (P < 0.01). The LF amplitude of blood pressure, an index of vasomotor sympathetic activity, showed marked rhythmic fluctuation at an interval of 48-100 s during head-up tilt (P < 0.01), synchronizing with similar fluctuation in the LF amplitude of heart rate (P < 0.01). These results suggest that CDM can be used to provide a continuous assessment of cardiovascular variability components and that the dynamic responses of autonomic circulatory control to upright posture result in a phasic modulation of LF amplitude.

Adult↗
PubMed1992

Characterization of GLUT3 protein expressed in Chinese hamster ovary cells.

We have expressed GLUT3 protein, an isoform of a facilitative glucose transporter, in Chinese hamster ovary cells by transfection of its cDNA using an expression vector. The expressed GLUT3 protein was detected by Western-blot analysis as a broad band of 45-65 kDa, indicating intensive glycosylation of the protein. The expressed GLUT3 protein was observed, by immunofluorescence staining, to be located mainly at the plasma membrane, and its expression was associated with a marked increase in glucose-transport activity. Kinetic analysis revealed that the Km value of GLUT3 protein for 3-O-methylglucose uptake was approx. 35% of that of GLUT1 protein, whereas the Km value of GLUT3 protein for 2-deoxy-D-glucose uptake was very similar to that of GLUT1 protein. The Vmax. value of GLUT3 protein for 3-O-methylglucose and 2-deoxyglucose uptake was approx. 20-50% of that of GLUT1 protein. GLUT3 protein was well photolabelled with [3H]cytochalasin B or a mannose derivative, 2-N-4-[3H](1-azi-2,2,2-trifluoroethyl)benzoyl-1,3-bis-(D-mannos -4-yloxy)-2- propylamine. Thus GLUT3 protein has very similar characteristics to GLUT1 protein including its subcellular localization, but exhibits lower Km and Vmax. values for 3-O-methylglucose uptake.

3-O-Methylglucose↗
PubMed1992

Domains responsible for the differential targeting of glucose transporter isoforms.

Facilitative glucose transporter isoforms, GLUT1 and GLUT4, have different intracellular distributions despite their very similar structure. In insulin-responsive tissues such as adipose tissues and muscle, GLUT4 protein resides mainly in the intracellular region in a basal condition and is translocated to the plasma membrane upon stimulation of insulin. In contrast, GLUT1 protein was distributed about equally between plasma membranes and low density microsomal membranes in 3T3-L1 adipocytes. Furthermore, GLUT1 and GLUT4 were reported to be differentially targeted to the plasma membrane and intracellular region, respectively, when expressed in Chinese hamster ovary cells and HepG2 cells. To elucidate the differential intracellular targeting mechanisms, several chimeric glucose transporters in which portions of GLUT4 are replaced with corresponding portions of GLUT1 have been stably expressed in Chinese hamster ovary cells. Immunofluorescence and immunoelectron microscopy as well as measurement of glucose transport activity revealed that two domains of GLUT4, which are not the NH2- or COOH-terminal domain, determine its targeting to the intracellular vesicles. The first domain contains the consensus sequence of the leucine zipper structure, suggesting that a dimer-forming structure of the glucose transporter might be required for its proper targeting. The other domain contains 28 amino acids, nine of which are different between GLUT1 and GLUT4. Immunoelectron microscopy revealed that the chimeric transporters containing both of these two domains of GLUT1, only the first domain of GLUT1, and none of the domains, exhibited a different cellular distribution with approximately 65, 30, and 15% of the transporters apparently on the plasma membrane, respectively. The addition of insulin did not alter the apparent cellular distributions of these chimeric transporters. These domains would be specifically recognized by intracellular targeting mechanisms in Chinese hamster ovary cells.

Animals↗
PubMed1992

Immunohistochemical localization of Na(+)-dependent glucose transporter in rat jejunum.

Glucose is actively absorbed via a Na(+)-dependent active glucose transporter (Na-GT) in the small intestine. We raised a polyclonal antibody against the peptide corresponding to amino acids 564-575 of rabbit intestinal Na-GT, and localized it immunohistochemically in the rat jejunum. By means of immunofluorescence staining, Na-GT was located at the brush border of the absorptive epithelial cells of the intestinal villi. Electron-microscopic examination showed that Na-GT was localized at the plasma membrane of the apical microvilli of these cells. Little Na-GT was found at the basolateral plasma membrane. Along the crypt-villus axis, all of the absorptive epithelial cells in the villus were positive for Na-GT. In addition to the brush border staining, the supranuclear positive staining, which was shown to be the Golgi apparatus by use of electron microscopy, was seen in cells located between the base to the middle of the villus. Cells in crypts exhibited little or no staining for Na-GT. Goblet cells scattered in the intestinal epithelium were negative for Na-GT staining. These observations show that Na-GT is specific to the apical plasma membrane of the absorptive epithelial cells, and that the onset of Na-GT synthesis may occur near the crypt-villus junction.

Animals↗
PubMed1992

Localization of erythrocyte/HepG2-type glucose transporter (GLUT1) in human placental villi.

The syncytiotrophoblast covering the surface of the placental villi contains the machinery for the transfer of specific substances between maternal and fetal blood, and also serves as a barrier. Existence of a facilitated-diffusion transporter for glucose in the syncytiotrophoblast has been suggested. Using antibodies to erythrocyte/HepG2-type glucose transporter (GLUT1), one isoform of the facilitated-diffusion glucose transporters, we detected a 50 kD protein in human placenta at term. By use of immunohistochemistry, GLUT1 was found to be abundant in both the syncytiotrophoblast and cytotrophoblast. Endothelial cells of the fetal capillaries also showed positive staining for GLUT1. Electron-microscopic examination revealed that GLUT1 was concentrated at both the microvillous apical plasma membrane and the infolded basal plasma membrane of the syncytiotrophoblast. Plasma membrane of the cytotrophoblast was also positive for GLUT1. GLUT1 at the apical plasma membrane of the syncytiotrophoblast may function for the entry of glucose into its cytoplasm, while GLUT1 at the basal plasma membrane may be essential for the exit of glucose from the cytoplasm into the stroma of the placental villi. Thus, GLUT1 at the plasma membranes of syncytiotrophoblast and endothelial cells may play an important role in the transport of glucose across the placental barrier.

Biological Transport↗