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Biomedical subjects

K Uehara

Publications and source records attributed to K Uehara.

At least 55 records · Page 3Linked to original sources
PubMed2000

Potassium-adsorption filter for RBC transfusion: a phase III clinical trial.

BACKGROUND: Within the past 2 years, three cases of cardiac arrest just after rapid transfusion of RBCs preserved for over 7 days after 15-Gy irradiation were found. This severe complication caused transient hyperkalemia. To prevent potassium (K(+)) overload by RBC transfusion at the bedside, a K(+)-adsorption filter made of sodium polystyrene sulfonate was developed. STUDY DESIGN AND METHODS: After in vitro and animal safety and efficacy tests, a Phase III clinical trial was conducted with 65 patients given transfusions via the newly developed filter (filter group) and 37 patients in whom the filter was not used (control group) and transfusions were given at twice the usual flow rate (20 mL/min). RESULTS: More than 85-percent (94.4+/-3.8%) removal of K(+) in RBCs in mannitol-adenine-phosphate (MAP) that had been preserved for more than 14 days or that were used 3 days after 15-Gy irradiation (calculated K(+): 3.8+/-1.3 mEq/bag) was achieved in 82 of 83 bags of MAP RBCs in the filter group, with 79.6 percent removed in the other, even in rapid transfusions. RBC recovery 1 day after transfusion, determined by increments in RBCs, Hb, and Hct, were 24 and 0.4 x 10(4) per microL, 0.7 and 0.3 g per dL, and 1.6 and 0 percent, respectively, in the filter and control groups. No adverse transfusion reactions, such as hypotension, anaphylactoid reactions, or asthma-like attacks, were observed, except for one case of urticaria in the filter group. Mild fever (within 1 degrees C) after transfusion was observed in both groups. Serologic markers of hemolysis rose slightly in both groups, but there was no significant difference between the two groups. CONCLUSION: The newly developed K(+)-adsorption filter is useful, especially in a rapid transfusion setting.

Adenine↗
PubMed2000

The effects of epimerization at the 3(1)-position of bacteriochlorophylls c on their aggregation in chlorosomes of green sulfur bacteria. Control of the ratio of 3(1) epimers by light intensity.

R- and S-epimerization at the 3(1) position of bacteriochlorophyll (BChl) c and the formation of rod-like aggregates in chlorosomes of green sulfur bacteria were markedly affected in Chlorobium (Cb.) tepidum and Cb. limicola by cultivation under various light intensities (photon fluence rate). The stronger the light, the higher the ratio of the S-epimer to the R-epimer for each homolog of BChl c in the bacteria. S[P,E] BChl cF and S[I,E] BChl cF were found to be the major S-epimers in Cb. tepidum and Cb. limicola, respectively. R[P,E] BChl cF decreased markedly compared to R[E,E] BChl cF in Cb. tepidum, whereas no observable change in the ratio of R[P,E]/R[E,E] was detected for Cb. limicola. With increase in light intensity the Qy absorption maximum of the bacteria shifted to shorter wavelengths. In vitro spectroscopic studies of the aggregates showed a marked difference in the formation of aggregates from R- and S-epimers of BChl c; the S-epimers formed aggregates much more slowly than did the R-epimers. These results suggest that the ratio of the epimers of BChl c might significantly affect the aggregation of BChl in the chlorosome. We propose different roles for the R- and S-epimers in chlorosomes of Cb. limicola and Cb. tepidum.

Bacterial Proteins↗
PubMed2000

[Awake pronation of surgical patients with cervical spinal lesions].

Positioning of patients with cervical spinal lesions under general anesthesia may lead to serious neurological complications. The authors attempted awake pronation in eighteen patients to minimize the risks. In all patients, cervical instability or cervical spinal cord compression was diagnosed, and posterior fusion or laminoplasty under general anesthesia was planned. Naso-tracheal intubation was performed by broncho-fiberoptic scope under topical anesthesia and light sedation. After tracheal intubation, pronation was completed while patients were still awake. Twelve patients could change their position almost by themselves, and needed only a little assistance of the medical staff. After the patients settled in appropriate position, general anesthesia was induced. Neurological status was assessed before and after the intubation, and just before the induction of general anesthesia, to prove the absence of complications. Operations were accomplished without major troubles in all patients. During post anesthetic interviews, eight patients had memory of the positioning, but none of them had any complaints about the procedure. Awake pronation may be useful to minimize the risk of neurological complications related to positioning of surgical patients, and also need less assistance by medical staff.

Anesthesia, General↗
PubMed2000

[Analysis of inadvertent epidural injection of drugs].

We asked 31 anesthesiologists, who were on the Japanese Board of Anesthesiology, about inadvertent injection of drugs into the epidural space, and received answers from 28 (90%). Fifteen (54%) had an experience of inadvertent epidural injection, and five of them had two experiences. Injected drugs were ephedrine (6 times), a mixture of neostigmine and atropine (3), thiopental (2), etilefrine (2), vecuronium (1), suxamethonium (1), bicarbonate (1), midazolam (1), lactated Ringer's solution (1), nicardipine (1), and pentazocine (1). The inadvertent injection of thiopental or bicarbonate was noticed by back pain during injection. No treatment was added after the inadvertent injections, except a patient with an epidural steroid injection following thiopental. No neurological complications were found in any patients.

Anesthesia, Epidural↗
PubMed1999

Multiple cerebral infarctions associated with ovarian hyperstimulation syndrome.

A 26-year-old woman on human menopausal gonadotrophin-human chorionic gonadotrophin therapy for sterility showed multiple cerebral infarctions associated with ovarian hyperstimulation syndrome. A hypercoagulable state (hemoconcentration, increased plasma levels of D-dimer and thrombin-antithrombin III complex, and decreased protein S activity) was associated with her thromboembolic events. Cerebral infarction associated with mild neurologic deficits may be overlooked in patients with ovarian hyperstimulation syndrome.

Adult↗
PubMed1999

Stress fiber networks in sinus endothelial cells in the rat spleen.

The wall of the splenic sinus is well known to be a critical site in the control of the blood-cell passage through the splenic cord. However, there is little information on what mechanism controls the blood-cell passage between the sinus endothelial cells adhered with intercellular junctions. Stress fibers of sinus endothelial cells in the rat spleen were examined by transmission electron microscopy and immunofluorescence microscopy. After extraction with saponin, the stress fibers were found to be conspicuously electron-dense in the basal portion of the cells and demonstrated two characteristic types and the mixed type of these. One type of the stress fibers was corrugated and formed thick, electron-dense bundles, and the other type had straight bundles with electron-dense areas at intervals. Statistically, the lengths of two types of stress fibers are significantly different. Although most of the stress fibers were segmented by the ring fibers, some of them ran successively beyond the attachment site of the ring fibers and thus stretched longitudinally and tangentially in the basal part of the cell to form a widespread network. The peripheries of the networks were attached to the basal plasma membrane at the ring fibers and the lateral membranes at the focal adhesions and the cell-cell adherens junction, respectively. Phosphotyrosine is localized in the basal part and at the intercellular adhesion site of the endothelial cells. Two types of stress fibers were organized in the sinus endothelial cells, and they form a widespread network. The possibility might be considered that stress fibers play important roles in the signal transduction and the regulation of cellular attachment and detachment.

Animals↗
PubMed1999

Tubular invaginations with caveolae and coated pits in the sinus endothelial cells of the rat spleen.

The fine structure of plasmalemmal tubular invaginations with caveolae and coated pits in the sinus endothelial cells of the rat spleen has been demonstrated by scanning and transmission electron microscopy. In addition, the three-dimensional structure of the tubular invagination has been revealed by computer-aided reconstruction. The tubular invaginations of the plasma membrane plunged into the cytoplasm everywhere from the apical, lateral, and basal surfaces of the plasma membrane. The invaginations were tubular and branched away, and their plasma membranes were reinvaginated to form numerous caveolae and occasional coated pits. Numerous caveolae were found in clusters that looked similar to a bunch of grapes and the coated pits were present at the base of the clusters. The caveolae and coated pits derived from the tubular invaginations were almost ultrastructurally identical to those derived from the surface plasma membrane. From examination of the fractured surfaces of the endothelial cells treated with the aldehyde prefix osmium-dimethyl sulfoxide-osmium method and of ultrathin sections of those infiltrated by lanthanum nitrate, the tubular invaginations were found to not penetrate any endothelial cells. A computer-aided reconstruction revealed that the caveolae derived from the tubular invaginations were in close apposition to the surface-connected canaliculi. The reaction product of Concanavalin A conjugated to horseradish peroxidase was present on the outer leaflet of the membranes of the coated pits and coated vesicles and also in the contents of the endosomes, but it was absent from any caveolae. Based on our observations, the functional significance of the tubular invaginations in sinus endothelial cells is discussed.

Animals↗
PubMed1999

The surface-connected canalicular system in the sinus endothelial cells of rat spleen.

The existence of a surface-connected canalicular system in the splenic sinus endothelial cells of the rat has been demonstrated by transmission electron microscopy with lanthanum nitrate acting as a tracer for the extracellular space. In addition, the three-dimensional arrangement of the canaliculi has been revealed by computer-aided reconstruction. The surface-connected canalicular system of the sinus endothelial cells consists of slender canaliculi that are branched, anastomosed, and that show continuity with the plasma membrane. They twist in and out among the organelles and are often found in close apposition to the spherical invaginations of the plasma membrane and run alongside them. Canaliculi which are not infiltrated by lanthanum nitrate take the form of electron-lucent tubules and are accompanied by numerous spherical invaginations of the plasma membrane. From a computer-aided reconstruction, the canaliculi, which invaginate from various sites of the plasma membrane, have been found to be continuous with each other and to penetrate to the surface of the sinus endothelial cell; they also branch and anastomose to form a complex network in the cytoplasm. Although the surface-connected canalicular system in blood platelets and thrombocytes is believed to function as the main route for the discharge of granules and the uptake of foreign materials and also to take part in the storage and transport of calcium, it is unclear at present whether the network of the surface-connected canalicular system in splenic sinus endothelial cells has any physiological significance.

Animals↗
PubMed1999

Tight junction of sinus endothelial cells of the rat spleen.

The fine structure of the tight junctions between sinus endothelial cells of the rat spleen and the permeability of such sinus endothelial cells were examined by transmission electron microscopy, using freeze-fracture, triton extraction, and lanthanum-tracer techniques. In freeze-fracture replicas, the segmented strands and grooves of the tight junctions were frequently observed on the basolateral surfaces of the sinus endothelial cells irrespective of the location of the ring fiber. There were one or two wavy-strands or grooves which were, for the most part, oriented parallel to the long cell axis thus forming networks at places. In addition, some strands or grooves were discontinuous while some networks of the junctional strands were not closed. These strands also occasionally lacked intramembranous particles in the tight junctions. The junctional strands run apicobasically at certain sites. In the vertical sections of the sinus endothelial cells treated with lanthanum nitrate, although no tight junctions were observed wherever the endothelial cells were apposed, most of them were situated on the basal part of the lateral surfaces of the adjacent endothelial cells. Several fusions of the junctional membranes were observed in a vertical section of the lateral surfaces of the adjacent endothelial cells. The intercellular spaces of the adjacent endothelial cells except for the fusion of the junctional membranes, were electron dense and the infiltration of lanthanum nitrate was found not to be interrupted by these tight junctions. Based on these observations, the molecular 'fence' and paracellular 'gate' functions of the tight junctions in the sinus endothelial cells are discussed.

Adult↗
PubMed1999

Morphology of intestinal colonization of Yersinia enterocolitica serovar O3 in mice.

The present study was made to know the morphology of the initial invasion and lesions involved in the intestinal colonization of Yersinia enterocolitica serovar O3 in the epithelium of Peyer's patches of mice. Microfold (M) cells formed a specific structure like a pseudopodium and the bacteria were observed on the surface of the pseudopodium-like structure 4 hr after oral administration of serovar O3. The colonies of serovar O3 were observed in the epithelium and the lamina propria of the Peyer's patches dome region, and the bacteria grown in the Peyer's patches were in direct contact with the lumen without covered with the host tissue 24 hr after the administration.

Animals↗
PubMed1999

Uptake of killed Yersinia enterocolitica by pseudopodia of M cells in the Peyers' patches of the murine small intestines.

To understand the mechanisms of uptake of killed bacteria of Yersinia enterocolitica serovar O3 into the epithelium of Peyer's patches, the killed bacteria were perorally inoculated into mice and observation was carried out by scanning and transmission electron microscopy. Microfold (M) cells formed a specific pseudopodium-like structure and the bacteria were observed on the surface and the interior of the pseudopodium-like structure 8 hr after oral administration of killed bacteria of serovar O3.

Animals↗
PubMed1999

Secretion of inhibin A, inhibin B and inhibin pro-alphaC during the oestrous cycle of the golden hamster (Mesocricetus auratus).

Plasma concentrations of inhibin pro-alphaC, inhibin A and inhibin B were determined by enzyme-linked immunosorbent assay at 6 h intervals throughout the 4-day oestrous cycle of the golden hamster. Plasma concentrations of follicle-stimulating hormone (FSH) and oestradiol-17beta were also measured by radioimmunoassay during the oestrous cycle. Plasma concentrations of inhibin A increased from the early morning of day 1 (day 1=day of ovulation) and reached plateau levels at 0500 h on day 2. An abrupt increase in plasma concentrations of inhibin A was found at 1700 h on day 4, when the preovulatory FSH surge was observed. An increase in plasma concentrations of inhibin B occurred on day 1 and reached plateau levels at 1700 h on day 1. The levels remained elevated until 0500 h on day 4 and declined gradually by 2300 h on day 4. Plasma concentrations of inhibin pro-alphaC gradually increased with some fluctuation from day 1 to 1700 h on day 4 and then declined. Significant negative relationships were noted between plasma FSH and both dimeric forms of inhibin from day 1 to day 3. Significant positive relationships were found between plasma oestradiol-17beta and inhibin A or inhibin pro-alphaC throughout the oestrous cycle. In contrast, no significant relationship was found between plasma oestradiol-17beta and inhibin B. These findings suggest that both dimeric forms of inhibin play a role in the regulation of FSH secretion during follicular development. These findings also suggest that inhibin pro-alphaC could be secreted primarily by large follicles, and early atretic follicles could also be responsible for inhibin pro-alphaC secretion. On the other hand, the secretory pattern of dimeric inhibins might shift from inhibin B to inhibin A with follicular development.

Animals↗
PubMed1998

Structural analysis of milk and testis beta-1,4-galactosyltransferase gene products.

There seems to exist a relatively low similarity between the amino acid sequences of the testis and milk beta-1,4-galactosyltransferase gene products. However, the predicted higher structures of testis and milk beta-1,4-galactosyltransferase proteins revealed a highly significant similarity in the regions required for enzymatic activities. Testis beta-1,4-galactosyltransferase protein contained a WD repeat similar to the motif of the G protein beta subunit type I and a Zn-finger motif at the N- and C-terminal portions of the protein, respectively. Phylogenetic analysis of glycosyltransferase proteins revealed that the ancestral gene of testis and milk beta-1,4-galactosyltransferases and alpha-1,3-galactosyltransferase evolved into three different destinations at about the same time on an evolutionary scale.

Amino Acid Sequence↗
PubMed1998

Higher sensitivity in induction of apoptosis in fibroblast cell lines derived from LEC strain rats to UV-irradiation.

The proportion of S-phase cells in a WKAH rat cell population decreased and that of G1-phase cells increased at 8 and 18 hr post-incubation following UV-irradiation, although no significant change was observed in the ratio of the proportion of S-phase to G1-phase cells in a LEC rat cell population. Thus, UV-radiation-induced delay in the progression from the G1 to S phase was observed in WKAH rat cells but was not apparent in LEC rat cells. The fraction of LEC rat cells containing a sub-G0 DNA content increased with post-incubation time after UV-irradiation, but not that of WKAH rat cells. The proportion of the sub-G0 fraction in LEC rat cells increased with increasing doses of UV-rays. Low molecular weight DNAs extracted from UV-irradiated LEC rat cells exhibited an intense DNA ladder pattern at 18 and 24 hr post-irradiation by electrophoretic analysis, but not those from UV-irradiated WKAH rat cells. These results showed a higher sensitivity of LEC rat cells in induction of apoptosis than that of WKAH rat cells to UV-irradiation, although there was no difference in the survival curves among the cell lines from LEC and WKAH rats after UV-irradiation.

Animals↗
PubMed1998

Inhibition of ovarian follicular development associated with a decrease in luteinizing hormone levels during the estrous cycle of the rat.

To examine the importance of tonic LH secretion in ovarian follicular development, plasma concentrations of LH were lowered by administering antiserum to GnRH (GnRH AS). At 1100 h on metestrus or diestrus of the 4-day estrous cycle, rats were injected with GnRH AS, and blood samples were collected at 6 h intervals until 1100 h on the next metestrus. Separately, rats were injected with hCG after the administration of GnRH AS to examine the effect of lowered LH on the number of ovulatory follicles. Treatment with GnRH AS on either metestrus or diestrus lowered plasma concentrations of LH, inhibin, and estradiol. In contrast, the plasma concentrations of FSH increased after the GnRH AS treatment, probably due to a decrease in plasma levels of inhibin associated with suppression of ovarian follicular development. Administration of GnRH AS on metestrus noticeably reduced the number of ovulatory follicles in spite of the high FSH secretion. Such a reduction in the number of ovulatory follicles was blocked by replacing rat LH with ovine LH. These data indicate that tonic secretion of LH plays an important role in the regulation of follicular development during the estrous cycle of the rat.

Animals↗
PubMed1998

[Basic principles and historical consideration of MR cholangiopancreatography].

Basic principle of MR cholangiopancreatography (MRCP) is heavily T2-weighted imaging (hydrography) to use bile and pancreatic juice as "natural contrast medium". Firstly developed sequence for MRCP was a CE-FAST sequence, which employed time-reversed FID signal. The current most popular sequences for MRCP are single-shot fast spin-echo sequences, which are divided into three types (2D single slice, 2D mutiple slice and 3D methods). The advantage of 2D single slice method is conveniently obtained projection imaging within a few seconds of examination time. Both 2D multiple slice and 3D methods consists of a MIP image and a series of source images. The MIP image creates global images of pancreatico-biliary system. The source images provide detailed evaluation of various anatomical structures and abnormalities. By using these sequences properly, MRCP can yield valuable informations of pancreatico-biliary diseases non-invasively.

Biliary Tract↗
PubMed1998

[Elimination of artifacts in MRCP: technical consideration].

Artifacts of MR cholangiopancreatography (MRCP) include fluid-filled gastrointestinal tracts, respiratory motion artifacts, spasm of Oddi's sphincter, vascular compression of bile ducts, overlapping of various anatomical structures and bright signal of surrounding fatty tissue. In this article, various technical considerations to eliminate these artifacts were described for the better imaging analysis of MRCP. The use of high-concentration ferric ammonium citrate (Ferriseltz) is recommended to reduce bright signal of fluid-filled gastrointestinal tracts. In case of long breathhold sequences, O2-inhalation study is useful to eliminate respiratory motion artifacts. Careful attention should be paid to the spasm of Oddi's sphincter and the vascular compression of bile ducts to avoid erroneous interpretation of MRCP findings.

Arteries↗