Biomedical subjects

K Tsuda

Publications and source records attributed to K Tsuda.

At least 181 records · Page 10Linked to original sources

PubMed1993

Productivity and some properties of egg yolk antibody (IgY) against human rotavirus compared with rabbit IgG.

Productivity and some properties of anti-Human Rotavirus (HRV) hen egg yolk antibody (IgY) were compared with those of anti-HRV rabbit serum antibody (IgG). The hens immunized with HRV (Wa strain, serotype 1 and Mo strain, serotype 3) were found to continuously to lay eggs without any change in the egg laying rate and the yolk of the eggs laid over a year showed a high level of neutralization titer against HRV. The production of anti-HRV IgY by a hen (one year) was at least 15 times (anti-Wa) and 120 times (anti-Mo) more effective than those by an immunized rabbit in the neutralization titer of the antibodies. The stability of anti-HRV IgY at temperature above 70 degrees C and low pH 2-3 was less than that of anti-HRV rabbit IgG. The temperature corresponding to the maximum of denaturation endotherm (Tmax) of IgY was 73.9 degrees C while that of rabbit IgG was 77.0 degrees C in the analysis by differential scanning calorimetry. This discrepancy in heat and acidic pH stability found between the two antibodies as discussed with regard to their protein structures.

Animals↗

PubMed1993

Treatment of hepatocellular carcinoma by chemoembolization: evaluation with 3DFT MR imaging.

OBJECTIVE: We evaluated the usefulness of an MR imaging technique that used dynamic three-dimensional Fourier transformation (3DFT) fast imaging with steady-state precession (FISP) with gadopentetate dimeglumine for detecting viable regions of hepatocellular carcinoma following transcatheter arterial chemoembolization with iodized oil (Lipiodol). Images obtained with the 3DFT FISP technique were directly correlated with hepatectomy specimens. SUBJECTS AND METHODS: Dynamic 3DFT FISP MR imaging was performed after transcatheter arterial chemoembolization and before partial hepatectomy in 10 patients with 10 tumors of hepatocellular carcinoma. Imaging parameters were 20/8/30 degrees (TR/TE/flip angle) with a slab thickness of 21-75 mm and seven or 15 partitions. 3DFT FISP images were obtained at the slice level where a tumor had been detected on T1- and/or T2-weighted spin-echo MR images before, just after (early phase), and 1 and 2 min after (late phase) IV administration of gadopentetate dimeglumine (0.1 mmol/kg). We directly compared the dynamic MR images of the 10 patients with the gross and microscopic findings. RESULTS: On early-phase images, tumors of hepatocellular carcinoma showed no enhancement in three patients and partial intense enhancement in seven. Viable regions of the tumor showed intense enhancement relative to the surrounding liver parenchyma in the early phase, whereas necrotic regions showed no enhancement in either the early or the late phase. Both viable and necrotic regions had lower signal intensities than did the surrounding liver parenchyma in the late phase. By using dynamic 3DFT MR imaging, we were able to accurately assess the effect of transcatheter arterial chemoembolization with iodized oil in nine of the 10 patients. However, in one patient in whom microscopically viable cells were seen in the capsule of the carcinoma, viable regions could not be detected with our technique. CONCLUSION: Dynamic 3DFT MR imaging was useful in differentiating viable regions of hepatocellular carcinoma from necrotic regions following transcatheter arterial chemoembolization with iodized oil.

Aged↗

PubMed1993

Immunoelectron microscopic studies of synaptic organization in the intralaryngeal ganglia of the cat.

The synaptic organization of nerve terminals containing calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP), substance P (SP) and enkephalin (ENK) in the intralaryngeal local ganglia of the cat was investigated by immunoelectron microscopy. CGRP-immunoreactive (IR) and VIP-IR varicose fibers formed mainly axo-dendritic synapses, whereas SP-IR and ENK-IR varicose fibers made axo-somatic synapses to the principal neurons of the local ganglion. The synaptic specializations of the CGRP-IR varicosities were asymmetrical, or Gray's type I, whereas the other peptide-IR varicosities showed symmetrical, or Gray's type II, synaptic specializations. After denervation of the extrinsic nerves, CGRP-IR varicose fibers disappeared from the ganglion, but VIP-IR, SP-IR and ENK-IR varicose fibers and synapses remained. These results suggest that local ganglia act as an integration center of laryngeal function rather than as a unidirectional parasympathetic relay center.

Animals↗

PubMed1993

Membrane fluidity of erythrocytes and its modulation by ouabain in essential hypertension--an electron paramagnetic resonance study.

The purpose of the present study was to examine alterations in membrane fluidity of erythrocytes in essential hypertension by means of an electron paramagnetic resonance (EPR) and a spin labeling method. In addition, we investigated the effects of ouabain on the fluidity of erythrocytes, and elucidated a possible role of Na+, K(+)-ATPase in the regulation of membrane fluidity in hypertension. Erythrocytes obtained from patients with essential hypertension were examined compared with those from age-matched normotensive subjects. The EPR spectra for 5-nitroxide stearate incorporated into erythrocyte membranes were studied. The values of the outer hyperfine splitting and order parameter (S) of the EPR spectra were significantly higher in patients with essential hypertension than in normotensive subjects. This finding shows that the membrane fluidity of erythrocytes might be lower in essential hypertension. Ouabain-loading of erythrocytes decreased the membrane fluidity (S value was increased). The ouabain-induced changes were significantly greater in essential hypertension than in normotensive subjects. These results demonstrate that the membrane fluidity of erythrocytes might be lower in essential hypertension than in normotensive subjects. Furthermore, the membrane fluidity might be highly dependent on the Na+, K(+)-ATPase activity in essential hypertension, which would suggest an abnormality in Na(+)-related cellular functions in hypertension.

Electron Spin Resonance Spectroscopy↗

PubMed1993

[Effects of loud noise on nasal skin temperature].

It has been demonstrated that stress conditions for babies such as a brief mother-infant separation cause the nasal skin temperature to drop. Changes in skin temperature may be taken as a representative sample of bodily reaction correlated with emotional changes. The purpose of this study is to investigate nasal skin temperature changes under loud noise situation. Fifty-two undergraduates were divided into two groups. Each group had 13 male and 13 female subjects. One group was given 100 dB and another was given 45 dB white noise. The Infrared Telethermograph Imager was used to measure nasal skin temperature changes. The results showed that the nasal skin temperature under 100 dB white noise decreased by about 0.5 degree C. However, under 45 dB no significant change was found. These findings suggest that the facial skin temperature will be one of the promising indices to detect various emotional changes.

Adult↗

PubMed1993

[Measurement of bone mineral density of metacarpal and phalangeal bones of the hand by dual X-ray absorptiometry].

Bone mineral density (BMD) of the metacarpal and phalangeal bones of the hand was evaluated using dual X-ray absorptiometry (DXA) in 104 healthy subjects, 35 patients with rheumatoid arthritis (RA) and 6 young male volunteers with a short arm cast. BMD was positively correlated with the bone volume of metacarpal and phalangeal bones in skeletal specimens. In healthy subjects, the mean values for BMD of metacarpals of the index and middle fingers were significantly higher than those of the ring and little fingers (p < 0.001). The BMD of the middle proximal phalanx was the highest among the proximal phalanges. The BMD of the middle phalanges was the same pattern as in the proximal phalanges. There was no significant difference in the BMD of the distal phalanges between the fingers. In 62 healthy women aged from 22 to 82 years, BMD was at its peak in the metacarpal and proximal phalangeal bones in their thirties, and in the distal phalanges in their forties. Thereafter, BMD decreased linearly with age. In contrast, age-related changes in BMD were not shown in 42 healthy men aged from 22 to 76 years. BMD of the metacarpal and phalangeal bones in RA markedly decreased with disease stage. Four-week immobilization of the hand by a short arm cast affected BMD of the metacarpal bones in 6 healthy volunteers. The mean change in BMD was -4.1% after 4 weeks of immobilization, followed by a return to the initial value in 12 weeks after removal of the plaster. We concluded that the bone mineral measurement of metacarpal and phalangeal bones could be useful for evaluation of age-related bone loss and the deterioration of bone in metabolic disorders.

Absorptiometry, Photon↗

PubMed1993

Detection of viable tumor cells in hepatocellular carcinoma following transcatheter arterial chemoembolization with iodized oil. Pathologic correlation with dynamic turbo-FLASH MR imaging with Gd-DTPA.

To evaluate the effect of transcatheter arterial chemoembolization (TACE) with iodized oil for hepatocellular carcinoma (HCC), dynamic turbo-fast low angle shot (turbo-FLASH) (TR/TE/flip angle/TI, 8.5/4.6/10/200) MR imaging with gadopentetate dimeglumine was performed in 10 patients with HCC after TACE with iodized oil and before partial hepatectomy. Immediately after 0.05 mmol/kg b.w. of gadopentetate dimeglumine was administered intravenously, 10 images were obtained in the first 20 s (early phase). Then, one image every 30 s from 1 to 3 min (late phase), and images at 5 min and 7 min (delayed phase) were obtained serially. In the early phase, HCC showed no enhancement in 5 patients, partial hyperintense enhancement in 4, and total hyperintense enhancement in one. Viable regions of the tumor, evaluated at histopathology, showed hyperintense enhancement relative to the surrounding liver parenchyma in the early phase, while necrotic regions showed no enhancement. Both viable and necrotic regions showed lower signal intensities than the surrounding liver parenchyma in both late and delayed phases. By using dynamic turbo-FLASH MR imaging, we were able to accurately evaluate the effect of TACE with iodized oil for HCC in 8 of the 10 patients. In 2 patients, in whom small viable cells were seen in the HCC, viable regions could not be detected with our technique. It is concluded that turbo-FLASH dynamic MR imaging was useful for evaluating the effect of TACE for HCC.

Aged↗

PubMed1993

[An hourglass type intrathoracic lipoma--a case report of surgical treatment].

We report a rare case of hourglass type intrathoracic lipoma. Until now, there are 114 reported cases on intrathoracic lipoma in Japanese literature, among which 22 are hourglass type. The patient was a 43-year-old woman, who was found to have a pleural tumor on her chest X-ray examination for healthy check-up. Computed tomography showed that it had intra- and extrathoracic portion with almost the same density as the subcutaneous fat tissue. The tumor was excised along with pleura, periostia and intercostal muscle approximately 1 cm apart from it. It was dumbbell-shaped and weighed 30 grams. Microscopically it was found to be intramuscular lipoma. According to Fletcher, intramuscular lipoma was classified into two groups of infiltrative and non-infiltrative type. In their cases, infiltrative intramuscular lipomas recurred up to 19%, mainly secondary to incorrect resection. Our case corresponds to infiltrative type. We consider that intrathoracic lipoma, though benign, have to be resected radically with utmost care.

Adolescent↗

PubMed1992

[MR imaging evaluation of plica synoviallis mediopatellaris of the knee joint].

To evaluate the diagnostic ability of MR imaging for plica synoviallis mediopatellaris (PSM), we retrospectively reviewed the MR imaging findings of patellofemoral space in 20 knee joints of 11 patients. In all 20 knee joints, arthroscopy and MR imaging were available. MR imaging was performed with a 1.5 Tesla Magnetom (Siemens) using a round surface coil. Pulse sequences were SE (TR 600 ms/TE 26 ms), SE (TR 200 ms/TE 26, 70 ms) and FLASH (TR 450 ms/TE 15 ms/FA 90 degrees). In six of the 20 knees with PSM proved by arthroscopy, a low intensity band was shown above the medial condyle of the femur on both T1- and T2-weighted MR images, and on FLASH images this band was shown as intermediate intensity. In the other 14 knees with no PSM observed by arthroscopy, the low intensity band was not shown on MR imaging. In all 20 knees, a similar low intensity band was shown about 1 cm cranial to the medial condyle of the femur. This should not be diagnosed as PSM. The low intensity band seen on T1- and T2-weighted MR images and its anatomical relation to the medial condyle are important in diagnosing PSM.

Adolescent↗

PubMed1992

[Dynamic 3DFT FISP MR imaging of hepatocellular carcinoma].

Dynamic 3 dimensional Fourier transformation (3DFT) FISP MR imaging was performed in 5 patients with hepatocellular carcinoma before partial hepatectomy. Immediately after 0.1 mmol/kg of Gd-DTPA was administered intravenously, 3DFT FISP images (TR/TE/flip angle/slice thickness, 20 msec/8 msec/30 degrees/2-4 mm) were obtained every 30 seconds until 150 sec. We correlated dynamic MR images of the 5 patients with gross and microscopic findings. Some regions in the tumor corresponding to viable cells showed high intensity enhancement and other regions corresponding to necrotic regions showed no enhancement on the early phase images. We concluded that dynamic 3DFT FISP MR imaging which had good spatial resolution was useful in evaluating the vascularity of the tumor.

Aged↗

PubMed1992

[Differentiation between hepatoma and hemangioma by inversion recovery snapshot FLASH MR imaging with variable TIs].

To differentiate hepatoma from hemangioma, MR studies were performed for 18 patients with 21 untreated liver tumors (hepatoma 10, hemangioma 11). We obtained inversion recovery snapshot FLASH images of liver tumors with variable TIs (50, 100, 150, 200, 250, 300, 400, and 500 msec). 8 hemangiomas showed higher intensity than liver parenchyma on the images at 150 msec and less of TI, and lower intensity at 200 msec or more TI. In 7, signal intensity of hepatoma became low at 150 msec or less of TI or remained high with prolonged TI. Inversion recovery snapshot FLASH imaging with variable TIs will be useful for differentiating between hepatoma and hemangioma.

Adult↗

PubMed1992

High HTLV-I proviral DNA level associated with abnormal lymphocytes in peripheral blood from asymptomatic carriers.

The level of proviral DNA in peripheral blood mononuclear cells from a representative group of asymptomatic HTLV-I carriers in Miyazaki district, an HTLV-I endemic area in Japan, was determined by a single-cycle polymerase chain reaction method (PCR). Of 217 subjects, 26% had a high level of proviral DNA, 43% a medium level, 18% a low level, and 13% an undetectable level. In the high-DNA group, 60% had at least 0.6% abnormal lymphocytes on peripheral blood smears, significantly higher than in those with low DNA levels (19%). This association was present for men of all ages and for women under 55. Men were more than twice as likely to have abnormal lymphocytes as well as high levels of proviral DNA. These differences may reflect different host responses to the virus by sex or by the time or route of infection. This study supports the utility of PCR for molecular screening in epidemiologic studies of the natural history of HTLV-I, and may lead to the identification of those carriers who are at greatest risk of developing HTLV-I-induced malignancy.

Age Factors↗

PubMed1992

Effects of verapamil on [3H]acetylcholine release in the striatum of spontaneously hypertensive rats.

In the present study, we describe the effects of Ca2+ channel antagonist (verapamil) on [3H]acetylcholine (ACh) release in the central nervous system of spontaneously hypertensive rats (SHR). The electrically stimulated release of [3H]ACh from striatal slices was not different between SHR and normotensive Wistar Kyoto (WKY) rats. Verapamil inhibited electrically stimulated [3H]ACh release in a dose-related fashion. The inhibitory effect of verapamil was significantly greater in SHR than in WKY rats. These results suggest that the Ca2+ sensitivity of central cholinergic neurons might be enhanced in SHR, which could attribute, at least partially, to the pathogenesis of hypertension.

Acetylcholine↗

PubMed1992

Stimulative effect of non-parenchymal liver cells on ability of tyrosine aminotransferase induction in hepatocytes.

Hepatocytes and non-parenchymal liver cells were isolated from adult rat liver and co-cultured for 48 hours as a monolayer on polystyrene culture dishes. The ability of tyrosine aminotransferase (TAT) induction in hepatocytes was examined in the presence of dexamethasone and dibutyryl cAMP. Non-parenchymal cells greatly enhance the ability of TAT induction of hepatocytes. A soluble factor with molecular weight of more than 10,000 is responsible for this enhancement, because conditioned medium prepared from non-parenchymal cells is also stimulatory. Non-parenchymal cells restored the ability in hepatocytes damaged with the addition of D-galactosamine. Conditioned medium prepared from non-parenchymal cells treated with D-galactosamine had higher activity of enhancement than the medium from normal cells. The soluble factor might be released in response to some signal of injury. Hepatocytes and non-parenchymal cells were immobilized within Ca-alginate, and although immobilized hepatocytes rapidly lost the ability to induce TAT, hepatocytes co-immobilized with non-parenchymal cells maintained the ability during 4 days of culture. These results indicated that non-parenchymal liver cells, as well as hepatocytes, could be used to construct a bioartificial liver support system.

Animals↗

PubMed1992

Glucagon, insulin and somatostatin secretion in response to sympathetic neural activation in streptozotocin-induced diabetic rats. A study with the isolated perfused rat pancreas in vitro.

Changes in glucagon, insulin and somatostatin secretion induced by electrical splanchnic nerve stimulation were examined in rats treated with streptozotocin as neonates and as adults. In order to study the direct neural effects we used the isolated perfused rat pancreas with intact left splanchnic nerve in vitro. In normal rats splanchnic nerve stimulation causes significant decreases in insulin (30-40%) and somatostatin (30-50%) secretion at both 16.7 mmol/l and 1 mmol/l glucose concentrations. In the neonatal streptozotocin-diabetic rat splanchnic nerve stimulation at 16.7 mmol/l glucose decreased insulin secretion (14%) further than in the control rats (30%), however, somatostatin secretion did not decrease to the same extent. Similar results were also observed at the low (1 mmol/l) glucose concentration. On the other hand, percent decreases of insulin and somatostatin secretion induced by splanchnic nerve stimulation in the streptozocin-diabetic rats were similar to the values observed in the normal control rats. The glucagon secretion in response to splanchnic nerve stimulation at 16.7 mmol/l glucose from pancreatic Alpha cells in both types of induced diabetes is exaggerated, and the degree of exaggeration seems to parallel the severity of the hyperglycaemia. However, the splanchnic nerve stimulation-induced glucagon secretion at 1 mmol/l glucose was impaired in the streptozotocin-diabetic rats, but not in the neonatal streptozotocin-diabetic rats. These data suggest that the sensitivity of diabetic Alpha and Delta cells to sympathetic neural activation are blunted, whereas the sensitivity of Beta cells is enhanced in the diabetic animal model.

Animals↗

PubMed1992

Facilitatory effects of diltiazem on dopamine release in the central nervous system. Focus on interactions with D2 autoreceptors and guanosine triphosphate binding proteins.

The purpose of the present study was to investigate the effects of a Ca antagonist (diltiazem) on dopamine release in the central nervous system. Rat striatal slices prelabeled with [3H]dopamine (DA) and superfused with Krebs-Ringer solution were stimulated electrically at a frequency of 1 Hz. Exposure to diltiazem (3.3 x 10(-7) to 1 x 10(-5) mol/L) significantly increased both the basal and stimulation-evoked [3H]DA release in a dose-dependent manner. Exogenously applied unlabeled DA inhibited the stimulation-evoked [3H]DA release. Diltiazem significantly antagonized the capacity of the unlabeled DA to inhibit stimulation-evoked [3H]DA release. The blockade of D2 receptors by a preferential D2 antagonist, sulpiride, reduced the facilitatory effect of diltiazem on stimulation-evoked [3H]DA release. Pretreatment with pertussis toxin, which interferes with the coupling of the inhibitory guanosine triphosphate-binding proteins to adenylate cyclase, significantly diminished the effects of diltiazem on stimulation-evoked [3H]DA release. These results show that diltiazem increased DA release in rat striatum, at least partially by interactions with the D2 autoreceptors and pertussis toxin-sensitive guanosine triphosphate-binding proteins.

Adenylate Cyclase Toxin↗

PubMed1992

Dihydrofolate reductase as a new "affinity handle".

Dihydrofolate reductase (DHFR) has been demonstrated to be a versatile "affinity handle" for expression of recombinant proteins. The DHFR "handle" has advantages not only in terms of efficiency of expressing the fusion protein as a soluble form but also in stabilizing unstable polypeptides and facilitating purification of the expressed protein by means of methotrexate-bound affinity chromatography and by making use of the enzyme activity. Fifteen genes encoding different lengths of polypeptides of 5 to 44 amino acids were chemically synthesized and introduced into expression vectors, pTP70-1 or its derivatives. All the polypeptide genes were efficiently expressed in Escherichia coli cells as fusion proteins which show DHFR activity. The respective fusion proteins were highly purified from cell-free extracts by monitoring the DHFR activity at each purification step. The use of methotrexate-bound affinity chromatography was very effective. In order to cut out the polypeptides, the purified fusion proteins were treated with either BrCN or site-specific protease according to the spacer sequence. The objective polypeptide was purified by means of a reversed-phase high-pressure liquid chromatography (HPLC) system. Specific cleavage of the purified fusion protein actually yielded very few peptide fragments, so the assignment and isolation of the objective polypeptide were carried out without difficulty.

Amino Acid Sequence↗

PubMed1992

Lack of homology between two haloacetate dehalogenase genes encoded on a plasmid from Moraxella sp. strain B.

Two genes encoding haloacetate dehalogenases, H-1 and H-2, are closely linked on a plasmid from Moraxella sp. strain B. H-1 predominantly acts on fluoroacetate, but H-2 does not. To elucidate the molecular relationship between the two enzymes, we compared their structural genes. Two restriction fragments of the plasmid DNA were subcloned on M13 phages and their nucleotide sequences were determined. The sequence of each fragment contained an open reading frame that was identified as the structural gene for each of the two dehalogenases on the basis of the following criteria; N-terminal amino acid sequence, amino acid composition, and molecular mass. The genes for H-1 and H-2, designated dehH1 and dehH2, respectively, had different sizes (885 bp and 675 bp) and G+C contents (58.3% and 53.4%). Sequence analysis revealed no homology between the two genes. We concluded that the dehalogenases H-1 and H-2 have no enzyme-evolutionary relationship. The deduced amino acid sequence of the dehH1 gene showed significant similarity to those of three hydrolases of Pseudomonas putida and a haloalkane dehalogenase of Xanthobacter autotrophicus. The dehH2 coding region was sandwiched between two repeated sequences about 1.8 kb long, which might play a part in the frequent spontaneous deletion of dehH2 from the plasmid.

Amino Acid Sequence↗