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Biomedical subjects

H Kurata

Publications and source records attributed to H Kurata.

At least 73 records · Page 4Linked to original sources
PubMed1998

Effects of exercise training and etidronate treatment on bone mineral density and trabecular bone in ovariectomized rats.

This study was designed to assess the effects of exercise training (Tr) following an etidronate treatment (E) on bone mineral density (BMD) of the femur and trabecular bone of the tibia in ovariectomized (ovx) rats. Female Wistar rats were ovariectomized (ovx) or sham-operated (sham) at 15 weeks of age and divided into five experimental groups: sham; ovx; ovx + E; ovx + Tr; ovx + E + Tr. Etidronate treatment of 5 mg/kg, 5 days/week was administered for 2 weeks and exercised on a treadmill for 30 m/min, 60 min/day, 5 days/week for 10 weeks. BMD of the femur and the trabecular bone area of the proximal tibia were significantly (p < 0.05) higher in E and/or Tr compared to ovx groups. However, the cortical region was not affected significantly by ovariectomy. The area partially filled with the trabecular bone at the constant width was observed only in the E rats. The number of osteoclasts in E group was significantly lower (p < 0.05) than in the ovx and ovx + Tr groups. The ovx + Tr rats had a higher number of osteoblasts (p < 0.05) than the ovx and ovx + E groups. There was a significant interaction between ovx + Tr and ovx + E on BMD in the proximal region of the femur (p < 0.05) and trabecular bone area of the tibia (p < 0.001). These results suggest that the etidronate treatment for 2 weeks beforehand influenced the effects of subsequent exercise training on maintaining the BMD in the proximal femur and the trabecular bone area of the tibia.

Absorptiometry, Photon↗
PubMed1998

Intermittent light irradiation with a second-scale interval enhances caffeine production by coffea arabica cells

We developed novel equipment that intermittently illuminates Coffea arabica cell suspensions at a second-scale interval and investigated how intermittent irradiation enhances caffeine biosynthesis by C. arabica cells. The light/dark cycles consisting of 2 s of illumination and 18 s of darkness enhanced caffeine production, reaching the same level as for continuous light. The intermittent illumination increased the production efficiency regarding light consumption by a factor of 10. Caffeine production was determined by light intensity regardless of intermittent or continuous light irradiation. We propose a new concept for designing a photobioreactor that is applicable to secondary metabolite production by plant cell culture.

Journal Article↗
PubMed1998

Stem cell factor induces proliferation and differentiation of fetal progenitor cells in the mouse.

We have investigated the kinetics of the amplification of the progenitor cell compartments (CFC) in haemopoietic organs during murine ontogenesis and compared the growth requirements of fetal and adult CFC. Two haemopoietic phases were recognized in the fetal liver (FL): an exponential growth phase, from 11.5 to 15.5 d post conception (p.c.), during which the mean number of nucleated cells and of CFC in the FL increased from 4.9 x 10(5) to 7.0 x 10(7) and from 4.5 x 10(3) to 2.7 x 10(5), respectively, and a recessive phase after 15.5 d p.c., during which the CFC number in the FL gradually decreased, although some CFC were still detectable in the liver after birth. In serum-deprived cultures, FL and adult marrow (AM) CFC had similar responses to GM-CSF, and did not respond to G-CSF or IL-3. In contrast, FL, but not AM, erythroid colonies grew Epo-independently whereas SCF alone induced formation of maximal numbers of erythroid bursts from FL, but not from AM cells. The proliferative and differentiative effect of SCF alone on fetal cells was confirmed in serum-deprived cultures of purified early progenitor cells isolated by cell sorting on the basis of multiple parameters from FL and AM light-density cells. In culture of purified FL cells, SCF alone induced a similar amplification of total cells (maximal amplification at day 12: 800-300-fold) and total CFC (11-38-fold of maximal amplification at day 6) to the combination of SCF plus IL-3 (1300-800-fold amplification of total cells and 31-88-fold amplification of CFC). In contrast, SCF alone allowed only survival of purified AM early progenitor cells. Therefore FL early progenitor cells have an intrinsic higher potential than their adult counterpart to respond to SCF, confirming the potent role of this growth factor in the development of the murine haemopoietic system.

Animals↗
PubMed1998

Alternate activity in the synergistic muscles during prolonged low-level contractions.

The purpose of this study was to investigate the functional interrelationship between synergistic muscle activities during low-level fatiguing contractions. Six human subjects performed static and dynamic contractions at an ankle joint angle of 110 degrees plantar flexion and within the range of 90-110 degrees (anatomic position = 90 degrees) under constant load (10% maximal voluntary contraction) for 210 min. Surface electromyogram records from lateral gastrocnemius (LG), medial gastrocnemius (MG), and soleus (Sol) muscles showed high and silent activities alternately in the three muscles and a complementary and alternate activity between muscles in the time course. In the second half of all exercise times, the number of changes in activity increased significantly (P < 0.05) in each muscle. The ratios of active to silent periods of electromyogram activity were significantly higher (P < 0.05) in MG (4.5 +/- 2.2) and Sol (4.3 +/- 2.8) than in the LG (0.4 +/- 0.1), but no significant differences were observed between MG and Sol. These results suggest that the relative activation of synergistic motor pools are not constant during a low-level fatiguing task.

Adult↗
PubMed1998

Idiopathic spinal cord herniation. Report of two cases and review of the literature.

The authors describe two occurrences of idiopathic spinal cord herniation, an entity that has been reported previously in only 11 cases. The patients described in this report presented in midlife with Brown-Séquard syndrome. Computerized tomography myelography and magnetic resonance (MR) imaging showed ventral displacement of the spinal cord with no apparent dorsal mass. Intraspinal cerebrospinal fluid (CSF) flow studies in which phase-contrast pulse sequence cine MR imaging was used displayed a normal pattern dorsal to the spinal cord. Percutaneous intrathecal endoscopic observation did not disclose dorsal intradural cysts, but ventral adhesions were seen between the spinal cord and the dura. Microsurgical intradural exploration revealed ventrolateral herniation of the cord and a ventral root through a dural defect into an epidural arachnoid cyst. The adhesions were released, the cord was repositioned intradurally, and the dural defect was patched. The patients showed gradual improvement postsurgery, as did most of the patients in the previously reported cases. The CSF flow and endoscopic studies were found to be particularly informative, and dural patching with surgical membrane is recommended.

Brown-Sequard Syndrome↗
PubMed1998

Evaluation of antifungal activity of an antifungal drug by in vitro simulation of in vivo pharmacokinetics of the drug against fungal hyphal growth.

An automatic drug concentration simulator (DCS) has been developed and its applicability has been demonstrated by in vitro simulation of the human plasma concentration-time curve of fluconazole (FLCZ) against hyphal growth of Candida albicans and Aspergillus fumigatus. The response of hyphal growth to FLCZ was continually monitored and analyzed using an automatic hyphal growth analyzing system (Bio-Cell Tracer). The simulated concentration of FLCZ by DCS was confirmed by HPLC. The DCS assay was reproducible with a mean coefficient of variation (C.V., n=3) of 5.38 %. When the growth of C. albicans hyphae was tested, there was a lag of onset of FLCZ effect between the time when FLCZ concentration became maximal (C MAX, 7.95 microg/ml ) and the point at which hyphal growth ceased. In contrast, FLCZ was found inactive against A. fumigatus. The newly devised technique could provide clinicians with important information in determining optimal dosing regimens for antifungal drugs.

Antifungal Agents↗
PubMed1998

A candidate high density lipoprotein (HDL) receptor, HB2, with possible multiple functions shows sequence homology with adhesion molecules.

High density lipoprotein (HDL), an antiatherogenic lipoprotein comprises several subclasses differing in composition and metabolic function. This physiological complexity appears to be matched with the growing number of candidate HDL receptors, since several HDL binding proteins have recently been identified in various tissues. Because these putative receptors may signal different pathways it is important to identify their structure and potential role in HDL metabolism. We review recent progress in the cloning and characterization of HB2, one of a pair of HDL binding proteins (HB1 and HB2) first purified from rat liver. The structure of HB2 is consistent with a receptor role for this membrane protein and when expressed in cells, increases HDL binding 2 fold. HB2, minimally present in THP-1 cells, is substantially upregulated in macrophages and appears sensitive to cholesterol loading of these cells. The protein shows high homology with adhesion molecules ALCAM and BEN and the possibility that HDL by binding to HB2, reduces adhesion induced arterial wall injury, is discussed in the context of the known protective role of HDL against atherosclerosis. The possible functions of HB2 are also compared with other recently cloned HDL receptors.

Animals↗
PubMed1997

Flow sensing in mycelial fungi.

Hyphae of a variety of mycelial fungi were shown to reorient their direction of growth to grow upstream in a continuous flowing current of liquid medium. Among those tested fungi, Aspergillus niger hyphae was most polarized towards the upstream. Hyphae of A. niger which had been attached to poly-L-lysine coated plates on the base of a continuous-culture flow cell were exposed to a current of medium of flow rates in the range of 0-6400 microns s-1 for 1-4 h. Hyphal tips quickly reoriented towards the upstream of the flowing medium and became aligned parallel to the flow axis as they grew larger. At flow rates above 1600 microns s-1, however, the percentage of polarization of hyphae reached a constant level. With other fungi, germ tube emergence was not polarized but hyphae and branches grew towards the upstream. There was no detectable difference in the pH and oxygen concentration of the flowing medium between inlet and outlet of the flow cell. This result suggests that hyphae of mycelial fungi sense transient flow of liquid medium over their surface and reorient their direction to grow upstream.

Aspergillus niger↗
PubMed1997

Cloning and characterization of HB2, a candidate high density lipoprotein receptor. Sequence homology with members of the immunoglobulin superfamily of membrane proteins.

The protection against coronary artery disease attributed to high density lipoprotein (HDL) may be associated with several functions, including its central role in reverse cholesterol transport, possible antioxidant and antithrombotic properties and others not yet identified which may depend on specific interactions between HDL and cell receptors. Several HDL-binding proteins have been identified including two candidate liver HDL receptors, HB1 and HB2 recently purified in this laboratory. We now report the cloning, sequencing, and some properties of HB2, the most abundant of the pair. It shows significant homology with the adhesion molecules ALCAM and BEN of the immunoglobulin superfamily and the cDNA, when transfected into HepG2 or COS cells, caused specific HDL3 binding to increase by 80-100%. Further, ligand blotting of glycoproteins isolated from phorbol 12-myristate 13-acetate-treated THP-1 cells or from transfected HepG2 and Chinese hamster ovary cells also provided evidence of increased binding of HDL3 to HB2. Differentiation of THP-1 cells into macrophages resulted in a striking increase in HB2 mRNA which was attenuated if cells were cholesterol-loaded by incubation with acetylated low density lipoprotein. If the interaction between HDL and HB2 reduces the adhesion-induced inflammatory cellular events that characterize arterial wall injury, thereby achieving the protection associated with higher plasma levels of HDL, these findings may provide a clue to one mitigating effect of HDL in heart disease.

Activated-Leukocyte Cell Adhesion Molecule↗
PubMed1997

Renal expression of serum-type mannan-binding protein in rat.

Mannan-binding proteins (MBPs) occur as liver and serum forms, which are encoded by separate genes and synthesized by the liver. Serum MBP plays a role in the first defense against a variety of pathogens. We found in this study, by reverse-transcriptional PCR, that rat serum MBP mRNA but not liver MBP is also expressed in the kidney. The level of the serum mRNA expression in the kidney as estimated by competitive PCR was about one-eighth that of the liver. Transcripts of serum MBP were detected in the renal corpuscles and distal convolutions by in situ hybridization. Affinity chromatography of the extract of rat kidney on a column of Sepharose-4B-mannan isolated a 29-kDa protein. These results indicate that serum MBP is synthesized in the kidney as well as in the liver. The kidney protein may be associated with local host defense around the kidney.

Animals↗
PubMed1997

Electromyogram patterns during plantarflexions at various angular velocities and knee angles in human triceps surae muscles.

To investigate the influence of the various knee angles and ankle angular velocities on synergistic muscle activities, the surface electromyograms (EMG) were recorded from the triceps surae muscles, i.e. lateral gastrocnemius (LG), medial gastrocnemius (MG) and soleus (SOL) muscles. Six healthy young men performed ankle plantarflexions at three ankle angular velocities of 6, 30 and 60 degrees.s-1 and three knee angles of 0, 30 and 60 degrees (0 degree equalling full extension) under constant load (5% and 10% maximal voluntary contraction). At the fully-extended knee angle (0 degree), peak values of integrated EMG (peak iEMG) during ankle plantarflexions were significantly increased (P < 0.05) in MG and in LG, but significantly decreased (P < 0.05) in SOL with increasing angular velocity. On the other hand, although the patterns of variation of the peak iEMG in each muscle at flexed knee angles (30 and 60 degrees) were very similar to the patterns seen at the fully-extended knee angle, there were no significant differences among angular velocities. During ankle plantarflexions at any of the angular velocities (6, 30 and 60 degrees.s-1) the peak iEMG were significantly increased (P < 0.05) in SOL, but were significantly decreased (P < 0.05) in MG following increases in the knee angles. These results would suggest the possibility of selective recruitment of motor units in humans depending on the angular velocity; however, this behaviour would appear to be weakened by fixing at flexed knee angles which cause an inhibitory influence on gastrocnemius muscles and a facilitative influence on SOL.

Adult↗
PubMed1997

Smoking cessation increases the resistance of low-density lipoprotein to oxidation.

The effects of smoking cessation on the susceptibility to oxidation of low-density lipoprotein (LDL) was investigated in 14 men who quit smoking for 3 months. LDL was isolated and susceptibility of LDL to V-70 (4-methoxy-2,4-dimethylvalerinitrile)-mediated oxidation was assessed by measuring conjugated diene production at 234 nm, the lag phase being a measure of the resistance of LDL to oxidation. The mean duration of the lag phase became 1.9-fold longer after 3 months (P < 0.001). The result suggests that the increase in resistance of LDL to oxidation contributes to the reduction of the risk of coronary heart disease by smoking cessation.

Adult↗
PubMed1997

[The clinical analysis of pediatric meningioma: 5 cases].

Five cases of pediatric meningioma were reported with special emphasis on the clinical features. These cases consisted of three boys and two girls between eight and fifteen years old. Two were falx meningioma, two were suprasellar, and one was petroclival. One falx meningioma was associated with Neurofibromatosis II, and a suprasellar case had no dural attachment, but had cystic component after recurrence. Histologically, there were three meningothelial, one transitional, and one fibrous meningioma. No malignant meningioma was found among any of the cases. Two cases received postoperative irradiation and had no recurrence. A falx meningioma with Neurofibromatosis II and a suprasellar with no dural attachment had evidence of recurrence. The latter suffered from severe neurological deficits after reoperation. It was suggested that irradiation against residual tumor should be considered. However, total removal should be carried out in pediatric cases of meningioma. The authors concluded that our cases had features intermediate between adult meningiomas and pediatric meningiomas because the majority of cases were senior children.

Adolescent↗
PubMed1997

[High-dose methylprednisolone pulse therapy for respiratory failure after open heart surgery].

After open-heart surgery, we sometime experience a patient whose respiratory function worsens extremely, though a heart function is improved. We experienced four such cases and treated with high-dose methylprednisolone. Then, we recognized that the respiratory function was improved at all cases. However, one case deteriorated again regarding the respiratory function, as a start of the treatment was delayed. There is a possibility that host resistance to infection is decreased by administration of corticosteroids. Therefore, we hesitate to treat with corticosteroids. Concerning respiratory failure after open heart surgery, however, we think that a respiratory function of a patient is improved if high-dose methylprednisolone pulse therapy is started in early stage.

Aged↗
PubMed1997

[A case of intracranial hemorrhage following superior sagittal sinus thrombosis associated with nephrotic syndrome].

A case of intracranial hemorrhage due to superior sagittal sinus thrombosis occurring in a boy with nephrotic syndrome is described. A twelve-year-old boy with nephrotic syndrome presented sudden onset of generalized convulsions. CT scan revealed a subcortical hematoma in the left frontal lobe. A left carotid angiography revealed the occlusion of the superior sagittal sinus. Neurological findings included disturbance of consciousness, right hemiparesis, and motor aphasia after the convulsions. All symptoms and signs disappeared immediately. There has been no evidence of rebleeding or convulsions for the last two years. This case had no abnormality of the coagulation system in routine investigation, but nephrotic syndrome and steroid therapy appeared to be associated with several disorders of the coagulation system. The authors suggested that it was necessary to pay attention to possible intracranial hemorrhage caused by cerebral venous sinus thrombosis in patients with nephrotic syndrome or who had undergone steroid therapy.

Cerebral Hemorrhage↗
PubMed1996

Acrania: report of the first surviving case.

The first known surviving case of acrania is presented. The patient was the first child of a 29-year-old Japanese woman. Fetal ventriculomegaly was documented in the 35th gestational week. Prenatal sonography and magnetic resonance imaging suggested hydrocephalus with a wide encephalomeningocele. The baby was born at 38 weeks of gestational age by vaginal delivery. The patient had no calvarium, but did have a complete skull base with a partial defect in the occipital scalp and an underlying dural defect. Subsequently, the patient underwent repair of the scalp defect. At 3 months of age, after hydrocephalus developed, a subduro-peritoneal shunt was placed because of cosmetic and nursing problems. His developmental quotient was 10 at 3 years.

Adult↗