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Biomedical subjects

K Okuda

Publications and source records attributed to K Okuda.

At least 217 records · Page 12Linked to original sources
PubMed1998

Coordinated expression of splice variants for luteinizing hormone receptor messenger RNA during the development of bovine corpora lutea.

We characterized splice variants for LH receptor mRNA in the bovine corpus luteum and examined the levels of expression of all the splice variants during the development of corpus luteum. Total RNA was extracted from bovine corpora lutea, and reverse transcriptase-polymerase chain reaction (RT-PCR) was performed to amplify a part of the extracellular and transmembrane domains. As a result, four distinct bands were observed on analyses with polyacrylamide gel electrophoresis, and sequencing of the products revealed that the largest form (519 bp) was the full-length A form and that the three shorter forms (438, 253, and 172 bp) were its splicing variants. Splicing patterns of the 438-, 253-, and 172-bp forms are identical to the F, B, and G forms, respectively, found in the ovine ovary. In order to examine the level of expression of all these splice variants simultaneously, semiquantitative RT-PCR was set up and performed. The relative intensities for all four forms of LH receptor mRNA significantly increased (P < 0.05) from Stage I (Days 1-4; Day 1 = day of ovulation) to IIS (Days 5-10, CL weight < 4 g), and from Stage IIS to IIL (Days 5-10, CL weight > or = 4 g). The intensities of all forms for LH receptor mRNA decreased slightly, but not significantly, from Stage IIL to III (Days 11-17). The ratios of the levels for all the forms did not change significantly during the development of the corpus luteum. Determination of the steady-state levels of LH receptor mRNA by Northern blotting showed similar changes during the development of the corpus luteum to changes of the splice variants examined by the semiquantitative RT-PCR. These results suggest that at least three splicing variants of LH receptor mRNA (i.e., F, B, and G forms) exist in the bovine corpus luteum and that the levels of all the forms of LH receptor mRNA increased in a coordinated manner during the development of bovine corpus luteum.

Alternative Splicing↗
PubMed1998

Right-sided pedunculated hepatocellular carcinoma: a form of adrenal metastasis.

Pedunculated hepatocellular carcinoma (HCC) or extrahepatic growth of HC C is an uncommon but not rare pathological form, but its genesis is unknown. Right-sided adrenal metastases of HCC that were abutting on or about to fuse with the right hepatic lobe were resected in three patients. The masses seemed to have originated in the para-adrenal tissue, leaving the adrenal gland intact. They were partially supplied by the hepatic artery as well as by the suprarenal artery. Four cases of autopsied pedunculated HCC of the right lobe were also studied. The mass was protruding caudad from the noncancerous parenchyma of the right lobe. Postmortem angiography carried out on one liver showed that only a small portion of the mass toward the liver was supplied from the hepatic artery. These observations suggest that some, perhaps most, of the right-sided pedunculated HCCs represent fusion of the right lobe and para-adrenal or adrenal metastatic HCC. This phenomenon may be explained by possible transport of cancer cells toward the right adrenal gland through the so-called adrenohepatic fusion, a relatively common anatomical change in advanced age.

Adrenal Gland Neoplasms↗
PubMed1998

Proposal of a new nomenclature for Budd-Chiari syndrome: hepatic vein thrombosis versus thrombosis of the inferior vena cava at its hepatic portion.

Budd-Chiari syndrome (BCS) was initially defined as a symptomatic occlusion of the hepatic veins, but subsequent reports on various obliterative changes that occur in the hepatic portion of the inferior vena cava (IVC) and hepatic vein orifices have resulted in a broadened and ambiguous definition. Membranous obstruction of the inferior vena cava has been regarded by many as a congenital vascular malformation, but its relation to the classical BCS has remained obscure. With modern imaging and recent histological study of new cases, membranous obstruction of the IVC is now considered to be a sequela to thrombosis. How to classify various forms of occlusion and stenosis of the IVC and hepatic vein ostia is a major challenge. In this review, we emphasize that primary hepatic vein thrombosis (classical Budd-Chiari) and an obliterative disease predominantly affecting the hepatic portion of the IVC, both of which account for most patients with venous outflow block, are clinically quite different. In the West, the former is more common than the latter, which constitutes the vast majority of cases of outflow block in developing countries such as Nepal, South Africa, China, and India. The latter is frequently complicated by hepatocellular carcinoma (HCC), and primary hepatic vein thrombosis is not. The major cause of thrombosis is a hypercoagulable state in hepatic vein thrombosis, but more of the latter cases are idiopathic. The clinical presentation of the latter is milder, and onset is frequently inapparent, whereas the former is more severe, sometimes causing acute hepatic failure. Markedly enlarged subcutaneous veins over the body trunk characterize the latter. We propose that these two disorders be clinically distinguished with a suggested term "obliterative hepato-cavopathy" for the latter against classical BCS.

Budd-Chiari Syndrome↗
PubMed1998

Intranasal administration of HIV-DNA vaccine formulated with a polymer, carboxymethylcellulose, augments mucosal antibody production and cell-mediated immune response.

We previously reported that intramuscular (i.m.) immunization of DNA vaccine encoding human immunodeficiency virus type 1 (HIV-1)IIIB env and rev genes alone or in combination with appropriate adjuvant induces substantial and enhanced immune response against HIV-1. In the present study, we examined whether a polymer, low-viscosity carboxymethylcellulose sodium salt (CMCS-L), has an adjuvant effect on immune response induced by DNA vaccination. BALB/c mice were immunized with HIV-DNA vaccine formulated with CMCS-L via the intranasal (i.n.) and i.m. routes. The combination with the polymer elicited higher levels of antigen-specific serum IgG and fecal IgA antibodies than DNA vaccine alone. For cell-mediated immunity, HIV-specific delayed-type hypersensitivity response and cytotoxic T lymphocyte activity were measured by the footpad-swelling test and the 51Cr-release assay, respectively. Both were enhanced by the combination with CMCS-L via i.n. and i.m. inoculation. Cytokine analysis in culture media of bulk splenocytes harvested from immunized animals showed higher levels of IL-4 production in i.n. -immunized mice compared with i.m.-immunized mice. Nevertheless, the increased IFN-gamma production resulting from the combination with CMCS-L was observed only in i.n.-immunized mice. These data indicate that i.n. immunization of HIV-DNA vaccine formulated with CMCS-L enhances HIV-specific mucosal antibody (Ab) and systemic Ab and cell-mediated immune response.

AIDS Vaccines↗
PubMed1998

Prolonged decreases in plasma nitrate levels at early postoperative phase after hepato-pancreato-biliary surgery.

Nitric oxide (.NO) is known to influence circulatory, neural, immunologic, and metabolic alterations. To evaluate the clinical significance of .NO production under surgical stress, serial measurements of plasma nitrite plus nitrate levels were performed in 45 surgical patients. Group A included 19 patients who underwent major surgery with uneventful postoperative courses. Group B included 18 patients who underwent laparoscopic cholecystectomy. Group C included 8 patients whose surgery was complicated by intra-abdominal abscesses. Eight healthy volunteers served as controls. Plasma nitrate levels were determined with a redox chemiluminescence .NO analyzer and coincided with measurements made by high-performance liquid chromatography (r = 0.868, p < 0.0001, 58 samples). During laparotomy, arterial nitrate levels correlated well with peripheral, portal, and hepatic venous nitrate levels (r = 0.966, 0.938, and 0.949, respectively; p < 0.0001). A significant decrease in nitrate from preoperative levels in groups A (postoperative day (POD) 1 and 3; p < 0.0005) and B (POD 1, p < 0.0001) was observed; nitrate levels in group C did not decrease for 14 days after surgery. Plasma nitrate levels in groups A and B were significantly different (POD 1 through 6, p < 0.05) and at POD 3 were significantly lower in group A (p < 0.005). Plasma nitrate levels measured before and after fasting or food intake were not significantly different. These results suggest that surgical stress leads to a decrease in the end product of .NO in the whole body, and that the greater the surgical stress the longer the duration of decreased .NO production.

Adult↗
PubMed1998

Melittin, a metabostatic peptide inhibiting Gs activity.

Some basic amphiphilic peptides are known to directly stimulate heterotrimeric GTP-binding proteins (G proteins). Mastoparan and melittin are known to stimulate Gi activities. Here, we found melittin inhibited guanine nucleotide-dependent adenylyl cyclase activity in synaptic membranes of the rat cerebral cortex. However, in insect cell membranes overexpressing specific heterotrimeric G proteins using baculovirus expression system, melittin showed unique effects different from those by mastoparan on G protein activities. This peptide markedly stimulated Gi1 and G11 activities, whereas it did inhibit Gs activities. Kinetic studies revealed that the inhibition of Gs activity by melittin is attributed to the inhibition of GDP release in exchange for added guanine nucleotides (or the association of guanine nucleotides). Thus, melittin may be the first metabostatic peptide inhibiting G protein (Gs) activity, and both mechanisms through the stimulation of Gi and inhibition of Gs might be involved in the melittin-induced inhibition of adenylyl cyclase.

Adenylyl Cyclases↗
PubMed1998

Stimulation of nitric oxide release from rat spinal cord by prostaglandin E2.

1. We recently demonstrated that intrathecal administration of prostaglandin E2 (PGE2) and PGF2alpha induced allodynia through a pathway that includes the glutamate receptor and nitric oxide (NO)-generating systems from pharmacological studies. In order to clarify the involvement of NO in prostaglandin-induced allodynia, we measured NO released from rat spinal cord slices by a chemiluminescence method. 2. PGE2 stimulated NO release from both dorsal and ventral regions all along the spinal cord. PGE2 stimulated the release within 10 min and increased it in a time-dependent manner. 3. The PGE2-induced NO release was observed at 100 nM-10 microM. PGF2alpha stimulated the release at concentrations higher than 1 microM, but PGD2 (up to 10 microM) did not enhance it. 4. 17-Phenyl-omega-trinor PGE2 (EP1 > EP3) and sulprostone (EP1 < EP3) were as potent as PGE2, but PGE1 was less potent, in stimulating NO release. While M&B 28767 (EP3) did not enhance the release, butaprost (EP2) stimulated it at 1 microM. The PGE2-evoked release was blocked by ONO-NT-012, a bifunctional EP1 antagonist/EP3 agonist. 5. The PGE2-evoked release was Ca2+-dependent and blocked by MK-801 (NMDA receptor antagonist) and L-NAME (NO synthase inhibitor). The release was also inhibited by PGD2 and dibutyryl-cyclic AMP. 6. The present study demonstrated that PGE2 stimulates NO release in the rat spinal cord by activation of NMDA receptors through the EP1 receptor, and supports our previous findings that the NO-generating system is involved in the PGE2-induced allodynia.

Animals↗
PubMed1998

Adjuvant effect of Ubenimex on a DNA vaccine for HIV-1.

Enhancement of DNA vaccine immunogenicity is a current topic of high priority in the field of applied immunology, especially as a means of controlling HIV infection. The adjuvant effect of Ubenimex (UBX), an anti-cancer immunomodulator, on a DNA AIDS vaccine which we developed was examined in a murine model. UBX was formulated into a preparation containing DNA plasmids encoding env and rev genes of HIV-1 strain III(B), and was inoculated intramuscularly into BALB/c mice. The sera obtained with this mixture had 2(3)-2(5) times higher specific IgG titres than those obtained without the use of the adjuvant. UBX also elicited both a stronger HIV-1-specific DTH reaction, as measured by the footpad swelling test, and stronger cytotoxic T lymphocyte activity, as assayed by the 51Cr-release method, compared with responses using DNA alone. The cytokine secretion profile of restimulated immune lymphoid cells showed that UBX raised IL-2 and interferon-gamma levels and decreased IL-4 production. HIV-1-specific immunoglobulin subtype analysis demonstrated that UBX stimulated IgG2a production but suppressed synthesis of IgG1 and IgE. These results indicate that activation of the T-helper type 1 subset was induced by UBX, suggesting a mechanism of immunomodulation mediated by this agent. We conclude that UBX acts as an immunologic adjuvant for DNA vaccination against HIV-1. UBX may be a suitable adjuvant for clinical use because of its lack of antigenicity and low toxicity.

AIDS Vaccines↗
PubMed1998

Intranasal administration of human immunodeficiency virus type-1 (HIV-1) DNA vaccine with interleukin-2 expression plasmid enhances cell-mediated immunity against HIV-1.

DNA vaccine against human immunodeficiency virus type-1 (HIV-1) can induce substantial levels of HIV-1-specific humoral and cell-mediated immunity. To develop more potent HIV-1 DNA vaccine formulations, we used a murine model to explore the immunomodulatory effects of an interleukin-2 (IL-2) expression plasmid on an HIV-1 DNA vaccine following intranasal administration of the combination. When the vaccine and expression plasmid were incorporated into cationic liposomes and administered to mice, the HIV-1-specific delayed-type hypersensitivity response and cytotoxic T lymphocyte activity were significantly increased. Restimulated immune lymphoid cells showed enhanced production of both IL-2 and interferon-gamma and reduced secretion of IL-4. The level of total antibody to HIV-1 antigen was not greatly changed by coadministration of the DNA vaccine and IL-2 expression plasmid. An analysis of serum HIV-1-specific IgG subclasses showed a significant drop in the IgG1/IgG2a ratio in the group that received the plasmid-vaccine combination. These results demonstrate that the IL-2 expression plasmid strongly enhances the HIV-1-specific immune response via activation of T helper type-1 cells.

Adjuvants, Immunologic↗
PubMed1998

Effect of flunitrazepam on sleep and memory.

Flunitrazepam's (FNZ) effect on sleep and memory 1 mg and 2 mg was investigated in 6 healthy volunteers (mean age 21.5 +/- 0.8 years) by polysomnography (PSG) and memory testing. A PSG was recorded on each study night. Memory testing was done before sleep (40 min after taking FNZ or placebo), and after waking (560 min after medication). Rapid eye movement (REM) latency was found to be prolonged on the FNZ 2 mg night (FNZ2N) compared to the baseline night (BN). Percentage of stage 2 sleep was increased in the FNZ2N as compared to BN, while REM percentage on both FNZ nights did not significantly differ from BN. The number of total REM and REM density were decreased in the FNZ2N compared to BN. Memory testing showed significant differences between before sleep and after waking on the FNZ2N. There was a significant correlation between the degree of impairment on memory testing and the rate of reduced REM density, but there was no significant correlation between degree of impairment on memory testing and the rate of increased non-REM sleep on the FNZ2N. The results of this study suggest that impairments in memory result from the dose of FNZ, and that there is a possibility of a relationship between memory disturbance and REM sleep suppression caused by this benzodiazepine.

Adult↗
PubMed1998

Predictive value of remnant-like particles cholesterol/high-density lipoprotein cholesterol ratio as a new indicator of coronary artery disease.

BACKGROUND: There is as yet no definite consensus on the predictive value of the various lipid profiles and fibrinolytic parameters that became available in clinical use recently for coronary artery disease. METHODS: Levels of lipoprotein(a), high-density lipoprotein cholesterol (HDL-C), remnant-like particles cholesterol (RLP-C), tissue plasminogen activator (TPA), TPA inhibitor, antithrombin III, and protein C were measured in 124 patients who underwent diagnostic coronary angiograms. RESULTS: Of these patients, 37 had no significant stenoses (group N) and 87 had significant stenoses (group S). There were no significant differences in patient characteristics between the two groups. HDL-C was significantly lower (p = 0.0071 ) and RLP-C was significantly higher (p = 0.0022) in group S. When a product and a ratio of each of two factors were calculated, RLP-C/HDL-C was demonstrated to be a highly significant predictor for coronary artery stenoses (p < 0.0001). There were also significant increases in RLP-C/HDL-C levels with increasing number of vessels involved (r = 0.359, p < 0.0001 ). CONCLUSION: Our present study disclosed the predictive value of RLP-C/HDL-C ratio as a new indicator of coronary artery disease.

Adult↗
PubMed1998

Autonomic dysfunction in elderly bedfast patients.

OBJECTIVE: to quantify autonomic function in bedfast elderly patients. PATIENTS AND METHODS: we analysed orthostatic blood pressure, heart rate response to tilt, heart rate response to deep breathing, quantitative sudomotor axon reflex test (QSART) and beat-to-beat blood pressure during phases II and IV of the Valsalva manoeuvre (VM) in 15 patients with (OH+) and without orthostatic hypotension (OH-) and 12 age-matched controls. RESULTS: all bedfast patients had a poor response in the late phase II of beat-to-beat blood pressure, while OH+ patients had an additional abnormality in phase IV. QSARTs in the distal leg and foot were decreased in both OH+ and OH- groups. There was no difference between the two groups in duration of being bedfast or in activities of daily living. CONCLUSIONS: (i) being bedfast results in postganglionic sympathetic dysfunction in the lower extremities; (ii) some patients who have beta-adrenergic dysfunction have OH and (iii) preventing patients from becoming being bedfast may be important for the maintenance of normal autonomic functions.

Aged↗
PubMed1998

Long-range effect of mutation of calcium binding aspartates [correction of asparates] on the catalytic activity of alkaline protease from Pseudomonas aeruginosa.

Apart from a catalytic domain, the alkaline protease of Pseudomonas aeruginosa has a novel parallel beta-helix domain stabilized through Ca2+ binding. In order to clarify the importance of the beta-helix structure in maturation of the enzyme, aspartic residue D-356 or D-365 in the Ca2+ binding sequence motif was replaced with L-alanine, and the catalytic activity of each mutant was assayed. These mutants did not show any proteolytic activity, although the composition of their polypeptide chains was the same as that of the wild type except for the mutated alanine residue. These results suggest that D-356 and D-365 are important in control of the beta-helix folding induced by Ca2+ binding and that incomplete beta-helix folding due to the lack of their side-chains affects the maturation of the enzyme in the long-range order.

Aspartic Acid↗
PubMed1998

Cryoglobulinaemia among maintenance haemodialysis patients and its relation to hepatitis C infection.

It has been shown that hepatitis C virus (HCV) infection is closely associated with mixed type cryoglobulinaemia. It is also known that HCV infection is rampant among chronic haemodialysis patients. We studied 531 renal failure patients on maintenance dialysis including 170 with positive HCV antibodies for cryoglobulinaemia, and its incidence was compared with controls which consisted of 242 chronic hepatitis C patients without renal failure and 183 healthy adults. Cryoglobulinaemia was present in 30.6% of dialysis patients with HCV infection, 10.8% of dialysis patients without HCV infection, 29.8% of patients with chronic hepatitis C without renal failure, and 0% of healthy adults. Among the 30 new renal failure patients who were started on dialysis within 6 months, four were positive for HCV antibodies, and one of them had cryoglobulinaemia; of the 26 HCV-negative patients, four (15%) were cryoglobulinaemic. The cryocrit values among dialysis patients were much lower than those of the control cases and other reports on non-dialysis cases. Patients with cryoglobulinaemia were generally younger compared with patients negative for this condition. There was no correlation between cryoglobulinaemia and past blood transfusion, underlying disease or length of dialysis. Cryoglobulinaemic patients seem to develop renal failure at relatively young ages and a considerable proportion of cryoglobulinaemic dialysis patients may have already had cryoglobulinaemia at the time of the start of haemodialysis. There was no indication that the presence of cryoglobulin in serum adversely affects the liver disease nor increases serum virus load in HCV-infected dialysis patients. Thus, it was concluded that although HCV infection has a certain role in the development of cryoglobulinaemia in dialysis patients, they develop cryoglobulinaemia less frequently and produce cryoglobulin to a lesser degree in the presence of HCV infection as compared with non-dialysis patients.

Adult↗
PubMed1998

Acute hepatitis C among renal failure patients on chronic haemodialysis.

Hepatitis C virus (HCV) infection is common in haemodialysis units, yet little information is available about the clinical feature of acute hepatitis C among renal failure patients. The present study is based on 49 cases of acute hepatitis C seen at a haemodialysis centre where sporadic nosocomial infection was occurring up to June 1993. Liver function tests were done at 4 weekly intervals on all dialysis patients, anti-HCV antibodies were tested by the C-100 and second generation tests and serum HCV-RNA was determined by the branched DNA and Amplicore tests. Diagnosis of acute hepatitis C was made on the basis of an acute rise in alanine aminotransferase (ALT) and seroconversion to positive anti-HCV antibodies. Clinical presentation of acute hepatitis was generally mild with rare overt jaundice and the diagnosis was possible only from increased ALT, which was generally low. Spontaneous resolution of acute hepatitis within 8 months with clearance of viral RNA occurred in only four cases, 91.8% of patients developing chronic hepatitis. Biopsy in 12 cases with high ALT levels showed mild to moderate inflammatory activities. In conclusion, the clinical presentation of acute hepatitis C is generally mild in chronic haemodialysis patients, but spontaneous resolution is infrequent. A longer follow-up period is required for defining the long-term prognosis.

Acute Disease↗