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Biomedical subjects

R Okamura

Publications and source records attributed to R Okamura.

At least 19 recordsLinked to original sources
PubMed2000

Extrahepatic large hepatocellular carcinoma with peritoneal dissemination: multimodal treatment, including four surgical operations.

We report a patient with extrahepatically growing large hepatocellular carcinoma (HCC) associated with disseminated intraabdominal tumor and spontaneous tumor bleeding who was treated with four operations, transcatheter arterial embolization, systemic chemotherapy, and hyperthermia. It took 12 months for the multimodal treatment to normalize the alpha-fetoprotein (AFP) level, and remission continued for 6 months. We performed the fourth surgical treatment for a recurrent abdominal tumor involving the small intestine and mesentery, but the patient died 26 months after the first admission. Multimodal treatment, including repeat surgical treatments, for such advanced HCC should be encouraged, to prolong life and to maintain quality of life.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

Wnt signaling regulates B lymphocyte proliferation through a LEF-1 dependent mechanism.

Lymphocyte enhancer factor-1 (LEF-1) is a member of the LEF-1/TCF family of transcription factors, which have been implicated in Wnt signaling and tumorigenesis. LEF-1 was originally identified in pre-B and T cells, but its function in B lymphocyte development remains unknown. Here we report that LEF-1-deficient mice exhibit defects in pro-B cell proliferation and survival in vitro and in vivo. We further show that Lef1-/- pro-B cells display elevated levels of fas and c-myc transcription, providing a potential mechanism for their increased sensitivity to apoptosis. Finally, we establish a link between Wnt signaling and normal B cell development by demonstrating that Wnt proteins are mitogenic for pro-B cells and that this effect is mediated by LEF-1.

Animals↗
PubMed1997

Ocular manifestations of familial amyloidotic polyneuropathy type I: long-term follow up.

AIMS: To obtain precise information on ocular manifestations of familial amyloidotic polyneuropathy (FAP) type I, the incidence of five main ocular manifestations--abnormal conjunctival vessels (ACV), keratoconjunctivitis sicca (KCS), pupillary abnormality, vitreous opacity, and glaucoma, were compared through long term follow up. METHODS: Ocular examinations were performed in 37 FAP type I patients (Met30) from once to 12 times over a period of 1 to 12 years and 7 months. RESULTS: The following incidences were observed on initial examination of each patient with FAP: ACV in 75.5%, pupillary abnormalities in 43.2%, KCS in 40.5%, glaucoma in 5.4%, and vitreous opacity in 5.4%. All ocular manifestations increased with the progression of FAP, and the incidence of ACV reached 100% during follow up: this may be helpful in the diagnosis of FAP. CONCLUSION: Since no precise statistical ocular study on FAP with long term follow up has been performed, this report may provide important information to help elucidate the mechanism of the amyloid distributing process in the amyloid targeted organs of FAP and to provide the natural course of ocular manifestations of FAP.

Adult↗
PubMed1996

Regional specification of motoneurons along the anterior-posterior axis is independent of the notochord.

Cek8 and low affinity NGF receptor (LNGFR) are expressed at high levels on the chick spinal motoneurons of the brachial and lumbar segments from embryonic day (E) 5 to E7, but weakly on the motoneurons of the non-limb-innervating segments. We determined by means of heterotopic neural tube transplantation, that the expression of these molecules was already intrinsically determined at E2. We used these spatiotemporal specific molecules as markers of motoneuron subpopulations. To analyze how motoneurons acquire regional specification along the anterior-posterior (A-P) axis and in the transverse plane, we observed the expression of these molecules on ectopic motoneurons induced by implanting a supernumerary notochord or floor plate at E2. The ectopic motoneurons induced by the graft obtained from either the thoracic or lumbar segments had the same expression profile as the normal motoneurons at each A-P level. These findings suggest that regional specification of motoneurons, at least of Cek8 and LNGFR expression, is independent of the notochord and the floor plate and that the whole neural tube appears to be committed to differentiate into the motoneuron subtypes along the A-P axis at the operative stages.

Animals↗
PubMed1996

[Studies on total nerve fivers of chorda tympani nerve in man].

An analysis of nerve fibers of the chorda tympani taken from six patients with otitis media cholesteatoma in whom the nerve could not be spared during tympanoplasty was performed. This study was designed to measure the diameter and the number of nerve fibers by making a full reconstruction of human chorda tympani in order to clarify the composition of myelinated and unmyelinated fibers, and to estimate the total number of fibers based on the results of the compartment measuring method. The following results were obtained: 1) The area of cross-section of the nerve ranged from 0.059mm2 to 0.110mm2, mean 0.081mm2. The sectional area was related to the patients age. 2) The total number of myelinated nerve fibers ranged from 3,305 to 4,668, with a mean of 3,829. The distribution of diameters of myelinated fibers had a peak at 2 to 3 microns and fibers of 1 to 4 microns accounted for 93.4% of the total. The number of myelinated fibers reduced with an increase in the patients age. 3) The total number of unmyelinated nerve fibers ranged from 2,044 to 4,334, with a mean of 3,306. The number of Schwann cell units was distributed between 791 and 1,937, with a mean of 1,386. The number of unmyelinated fibers per one Schwann cell unit ranged between 1 and 5 in 93.6% of cases. There was no age-related reduction in the number of fibers. 4) Comparing the actual measurements and the result of the compartment measuring method, the distribution of the diameter of myelinated fibers could be approximated by sampling three compartments, which area was 0.0048mm2. The total number of nerve fibers could be estimated by sampling three compartments for myelinated fibers and four compartments, one of which contained unmyelinated fibers, for unmyelinated fibers. 5) The measurement of the number of nerve fibers by the compartment measuring method and the microscopic observation indicated the locality of unmyelinated fibers. These localized fibers were speculated to be secretory fibers to hypoglossal and submandibular glands.

Adolescent↗
PubMed1995

Secondary amyloidosis with severe autonomic dysfunctions.

A 46-year-old male underwent hemodialysis because of progressed glomerulo-nephritis. Since he suffered from severe diarrhea during the course of the illness, both gastric and colon biopsies were performed. Significant amyloid deposition was recognized in the submucosal layer of these specimen. This amyloid was positive for anti-AA-protein antibody staining and soluble in KMnO4 solution, indicating secondary induced amyloid. Despite of absence of orthostatic hypotension, examinations revealed extreme reduction in tears and salivary secretion, anhidrosis, a decrease in the coefficiency of variation of the cardiographic R-R interval, and a decrease in the accumulation of [123I]meta-iodobenzylguanidine (MIBG) in the heart, suggesting that severe glandular and visceral autonomic dysfunctions had occurred in the patient.

3-Iodobenzylguanidine↗
PubMed1995

Antiviral effect of oryzacystatin, a proteinase inhibitor in rice, against herpes simplex virus type 1 in vitro and in vivo.

Oryzacystatin (OC) is the first-described cystatin originating from rice seed; it consists of two molecular species, OC-I and OC-II, which have antiviral action against poliovirus in vitro (H. Kondo, S. Ijiri, K. Abe, H. Maeda, and S. Arai, FEBS Lett. 299:48-50, 1992). In the experiments reported here, we investigated the effects of OC-I and OC-II on the replication of herpes simplex virus type 1 (HSV-1) in vitro and in vivo. HSV-1 was inoculated onto monolayers of monkey kidney epithelial cells (CV-1 cells) at a multiplicity of infection of 0.1 PFU per cell. After adsorption of the virus onto cells, the cultures were incubated in the presence of either OC-I or OC-II in the concentration range of 1.0 to 300 microM, and the supernatant virus yield was quantitated at 24 h. The effective concentration for 90% inhibition of HSV-1 was 14.8 microM, while a cytotoxic effect on CV-1 cells without infection of HSV-1 was not observed below 500 microM OC-I. Therefore, the apparent in vitro chemotherapeutic index was estimated to be more than 33. In the mouse model of HSV-1-induced keratitis and encephalopathy, topical administration of OC-I to the mouse cornea produced a significant decrease in virus production in the cornea (mean virus yields: 3.11 log10 PFU in the treated group and 4.37 log10 PFU in the control group) and significant improvement in survival rates (P = 0.01). The in vivo antiherpetic effect of OC-I was comparable to that of acyclovir, indicating that topical treatment of HSV-1 infection in humans with OC-I might be possible. Our data also suggest the importance of some thiol proteinases, which may be derived from either the host's cells or HSV-1, during the replication process of HSV-1.

Animals↗
PubMed1994

Therapeutic intervention with chicken egg white ovomacroglobulin and a new quinolone on experimental Pseudomonas keratitis.

BACKGROUND: Chicken egg white ovomacroglobulin (ovoM) is a potent protease inhibitor with broad-spectrum activity against various proteases. The combined effects of ovoM and the new quinolone, ofloxacin (OFLX) on experimental Pseudomonas aeruginosa keratitis were investigated. METHODS: The in vitro inhibitory effects of ovoM on protease activity in culture fluid of clinically isolated P. aeruginosa and on activity of human neutrophil elastase and cathepsin G were assayed using azo-casein as substrate. Albino rabbits received intrastromal injection of the isolated Pseudomonas strain (1 x 10(5) colony-forming units). At 16 h after inoculation, three treatment groups--0.1% ovoM alone, 0.3% OFLX alone, and a combination of both--and a non-treatment control group were tested. RESULTS: Protease activity in the culture solution and human neutrophil elastase was inhibited by ovoM, whereas cathepsin G was not inhibited effectively. In vivo additive therapeutic effects of ovoM and OFLX were observed at 96 h (P < 0.05 compared with OFLX alone). CONCLUSION: The results indicate that inhibition of proteolytic activity with ovoM is useful in preventing stromal degradation in P. aeruginosa keratitis.

Animals↗
PubMed1994

Presacral epidermal cyst found in an adult male with a high CEA content: report of an unusual case.

A 63-year-old Japanese man presented with constipation, having noticed flat stools for several years. Digital examination of the rectum, followed by barium enema, colono-fiberscopy, computed tomography (CT), and magnetic resonance imaging (MRI) revealed an oval mass located between the retrorectal and presacral space without any mucosal lesion. This mass had narrowed the rectal lumen by compressing the rectum anteriorly. Although the plasma levels of the tumor markers were within the normal range, those of the tumor contents were elevated with a carcinoembryonic antigen (CEA) of 118 ng/mL, while the alpha-fetoprotein (AFP) value was 1 ng/mL. The tumor was completely extirpated through an abdominal incision, and there has been no evidence of recurrence thus far. Histological examination showed that the tumor wall was made of keratinized stratified squamous epithelium without any cutaneous adnexal structure, and hence it was diagnosed as an epidermal cyst. CEA was identified in these benign epithelial cells by immunoperoxidase staining using a monoclonal antibody. To the best of our knowledge, there have been only four other cases with a presacral epidermal cyst documented in the Japanese literature, all of whom were female. Our patient is the first reported case of an adult male with a presacral epidermal cyst.

Carcinoembryonic Antigen↗
PubMed1994

Suppression of polymorphonuclear leucocyte chemotaxis by Pseudomonas aeruginosa elastase in vitro: a study of the mechanisms and the correlation with ring abscess in pseudomonal keratitis.

Bacteria, or the culture supernatants of an elastase non-producing strain of Pseudomonas aeruginosa, elicited a chemotactic response from polymorphonuclear leucocytes (PMN) in vitro. The chemoattractive capacity was diminished under the presence of Boc-Phe-Leu-Phe-Leu-Phe, a receptor antagonist of N-formyl-Met-Leu-Phe (fMLP) which is a bacterial chemotactic peptide to PMN. This indicated that the chemoattractant derived from Pseudomonas aeruginosa was a fMLP-like molecule(s). In contrast, culture supernatants of an elastase producing strain of Pseudomonas aeruginosa produced negligible chemotactic response from PMN. Indeed, an inhibitory effect of the culture supernatants or of purified Pseudomonas aeruginosa elastase (PAE) on PMN chemotaxis was observed when fMLP was used as a chemoattractant. Another fMLP-induced function of PMN, respiratory burst activation, was also diminished by pretreatment of PMN with PAE. PAE hydrolysed fMLP at the Met-Leu bond and diminished the chemoattractant capacity. In addition, a receptor analysis with fML-3H-P demonstrated a decrease in numbers of fMLP receptors on PMN without changing the dissociation constant values after the treatment of the cells with PAE. In the primary structure of the fMLP receptor previously reported, a preferential amino acid sequence for cleavage by PAE was identified in what was believed to be an extracellular portion of the receptor molecule. These results suggested that PAE could diminish PMN infiltration in response to Pseudomonas aeruginosa in vivo by cleavage of the fMLP-like pseudomonal chemotactic ligand and the receptors on PMN.

Abscess↗
PubMed1994

[Effect of prophylactic intra-arterial infusion of anticancer drugs on post hepatic resection for hepatic metastasis of colorectal cancer].

Prophylactic intra-arterial infusion of anticancer drug on post hepatic resection for hepatic metastasis of colorectal carcinoma were performed 8 cases. In our cases consisted of 8 patients of mean age of 54.3 years (male 3 cases and female 5 cases, synchronous metastasis 4 cases and metachronous 4 cases). All patients were received intra-arterial bolus injection of MMC (4-8 mg/body) at day 1 and continuous infusion of 5-FU (250-750 mg/body) for 7 days on admission. After discharged, patients were received bolus injection of 5-FU (250-750 mg/body) for once a week. Side effect of this treatment was not appeared and all of them obtained very good QOL. There were no recurrence sign of residual liver and this procedure was very useful method for post hepatic resection for hepatic metastasis of colorectal cancer.

Adult↗
PubMed1993

Chicken ovalbumin upstream promoter-transcription factor (COUP-TF) represses transcription from the promoter of the gene for ornithine transcarbamylase in a manner antagonistic to hepatocyte nuclear factor-4 (HNF-4).

Chicken ovalbumin upstream promoter-transcription factor (COUP-TF) and hepatocyte nuclear factor-4 (HNF-4) are orphan members of the steroid/thyroid receptor superfamily and exhibit ubiquitous and liver-enriched tissue distribution, respectively. The gene for rat ornithine transcarbamylase (OTC), an ornithine cycle enzyme, is mainly expressed in the liver and is under the control of the promoter and the 11-kilobase upstream enhancer, both of which are liver-selective. Two sites of the promoter region and two sites of the enhancer region of the OTC gene, as well as the ovalbumin promoter site, were recognized by both HNF-4 and COUP-TF, showing that these two factors have closely related binding specificities. Since HNF-4 activated expression from the OTC promoter in cotransfection analysis, this factor appears to participate in liver-selective activation of the OTC gene. On the other hand, COUP-TF repressed the expression from the OTC promoter, whereas it activated expression from several other promoters. Therefore, COUP-TF plays a dual regulatory role depending on the promoter context. Repression of a tissue-specific promoter by a ubiquitous transactivator and derepression by a related tissue-enriched transactivator is potentially an important mechanism for tissue-specific activation of a gene.

Animals↗
PubMed1993

The role of Pseudomonas aeruginosa elastase in corneal ring abscess formation in pseudomonal keratitis.

In order to identify the causative factors of ring abscess, which is the characteristic feature of pseudomonal keratitis, pseudomonal endotoxin, exotoxin A, and elastase were each separately injected into guinea pig cornea. There was no formation of ring abscess. Injection of living Pseudomonas aeruginosa strains IFO3455 and Takamatsu which produce all three molecules, clearly induced ring abscess. In contrast, when heat-killed bacteria strain IFO3455 or living bacteria of the non-elastase-producing strain PA103 were injected, ring abscess was not induced. Furthermore, when living bacteria strain IFO3455 were injected with anti-elastase antibody or a protease inhibitor, ovomacroglobulin, ring abscess formation was significantly inhibited. Histological examination demonstrated that the ring abscess was a dense accumulation and aggregation of polymorphonuclear leukocytes (PMN) with debris of cells and lamellae in the deep stroma at the corneal margins, suggesting prevention of PMN migration to the central lesion. The presence of anti-elastase antibody or a specific elastase inhibitor facilitated PMN migration towards living bacteria strain IFO3455 in an in vitro model. These results indicate that pseudomonal elastase is a necessary but not sufficient factor in the formation of ring abscess in pseudomonal keratitis.

ADP Ribose Transferases↗
PubMed1993

Metallic expanding biliary stents in malignant obstruction. Cases with stent in stent.

We reviewed a total of 13 stent (Gianturco-Rosch biliary Z-stent) placements in 11 patients with biliary obstruction due to malignancy and report the cases treated with the stent-in-stent technique for treatment of stent occlusion due to tumor ingrowth. Causes of biliary obstruction included cholangiocarcinoma (four cases), hepatic hilar metastasis of gastrointestinal carcinoma (five cases), and pancreatic carcinoma (two cases). After transient percutaneous transhepatic biliary drainage (PTBD), the stents were successfully inserted by transhepatic route in all patients without any serious complication that needed further surgical intervention. Almost all patients were freed from the external PTBD tube about a week after stent placement and discharged from the hospital with improvement in quality of life as well as normal serum bilirubin levels. The technical advantages of stent placement include ease of insertion and the ability to drain both right and left biliary systems from a single transhepatic route by arranging the stents in a variety of configurations. Furthermore, it provides a second chance of stent placement when the previous stent has been occluded by tumor ingrowth.

Aged↗
PubMed1993

Effects of external high K+ on Na+ and H+ activities at the posterior cortical layers of rat lens in vitro.

Intralenticular Na+ and rat lens H+ activities (aNa and pHi, respectively) were measured in vitro at the posterior cortical layers of lens fibers using ion-selective microelectrodes. In control HCO(3-)-free solution (K+: 5 mM; external pH (pHo): 7.3), intralenticular potential (Vm) was -61.5 +/- 2.4 mV, aNa was 19.4 +/- 4.6 mM and pHi was 6.90 +/- 0.06 (mean +/- SD). In O-mM K+ solution, Vm slightly depolarized, but aNa and pHi did not change. Increasing K+ concentration to 35 mM induced a large depolarization of Vm, associated with a reduction in aNa and an increase in pHi. pHi was decreased by lowering pHo, but internal acidification thus induced did not show a complete recovery upon reintroduction of a normal solution. The pHi was immediately increased by superfusion with a solution containing 20 mM NH4Cl, and subsequent removal of NH4Cl led to a sustained decrease in pHi. Ouabain and amiloride (a blocker of Na(+)-H+ exchanger) did not exert any effects on aNa or on pHi in normal solution at pHo 7.3. Amiloride applied after the removal of NH4Cl did not alter pHi. These results provide evidence that aNa and pHi at the posterior cortical fiber layers of the rat lens are influenced by Vm, and that, depending on the value of Vm, passive movements of Na+ and H+ can exert direct local effects on pHi and aNa.

Amiloride↗
PubMed1993

Inhibition of in utero galactose-induced cataract development by an aldose reductase inhibitor in rat--electron microscopic study.

The effect of an aldose reductase inhibitor (ARI) on the development of in utero galactose-induced cataract was evaluated by following the morphological changes as seen by light and transmission electron microscope. Pregnant rats were fed a 30% galactose diet until day 17, 18, 19 or 20 of gestation and then given a galactose diet containing ARI. The lenses of newborn rats when mothers were given an ARI diet after day 17, 18 or 19 of gestation showed no morphological change. On the other hand, in the lenses from newborn rats when mothers were given an ARI diet after day 20 of gestation, 30% of those tested showed small vacuoles limited to the posterior cortex, while 70% showed normal structure. When mothers were given a galactose diet during the entire term of pregnancy all lenses of newborn rats showed extensive vacuole formation. ARI was confirmed to completely inhibit congenital galactose cataracts in rats when it was given to the mother rat after day 19 of gestation (ie, on the last 3 days before delivery).

Aldehyde Reductase↗
PubMed1993

Effect of pregnancy on development of galactose-induced cataract in rat.

The effect of pregnancy on the development of galactose-induced cataract was studied in rats. Eight-week-old rats were fed a 50% galactose diet for 4 weeks. The rats were divided into three groups: nonpregnant females, pregnant females, and males. All eyes were examined by slit-lamp biomicroscope at 11 and 12 weeks of age, and the lenses were morphologically examined at 12 weeks. Clinically, the cataract showed a less advanced stage in the eyes of pregnant rats than in the eyes of the other two groups. Morphologically, the lenses of pregnant rats retained their normal structure. However, the lenses of the other two groups showed extensive damage. The plasma galactose levels and galactitol levels in lenses showed no significant difference among the three groups. Pregnancy was proved to inhibit the development of galactose cataract.

Animals↗