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Biomedical subjects

K Higuchi

Publications and source records attributed to K Higuchi.

At least 91 records · Page 5Linked to original sources
PubMed2000

Intraoperative map guided operation for atrial fibrillation due to mitral valve disease.

BACKGROUND: This study was designed to determine if intraoperative atrial activation mapping facilitates operations for chronic atrial fibrillation associated with mitral valve disease. METHODS: Surgical treatment guided by intraoperative electrophysiologic mapping was performed in 12 patients with chronic atrial fibrillation associated with isolated mitral valve disease. In 10 of 12 patients, regular and repetitive activation (cycle length ranged from 118 to 210 msec) originated in the left atrial appendage and/or orifice of the left pulmonary vein. In the remaining 2 patients, dominant repetitive activation and sporadic complex activation were alternately observed in the left atrium. However, the activation sequence of the right atrium was extremely complex and chaotic. RESULTS: On the basis of intraoperative mapping, surgical procedures, including resection of the left atrial appendage and/or cryoablation of the orifice of the left pulmonary vein, were applied on the breakthrough site of the repetitive activation. No surgical procedure was performed on the right atrium in 11 patients. Ten of 12 patients (83%) have maintained sinus rhythm for 6 to 40 months (average 24.8 months) after operation. CONCLUSIONS: In the majority of the patients with isolated mitral valve disease, the left atrium acts as an electrical driving chamber for chronic atrial fibrillation. Computerized intraoperative mapping should guide surgeons in determining the appropriate surgical procedure for chronic atrial fibrillation.

Aged↗
PubMed2000

Cloning and characterization of a Bacillus thuringiensis serovar higo gene encoding a novel class of the delta-endotoxin protein, Cry27A, specifically active on the Anopheles mosquito.

A novel gene encoding a 98-kDa mosquitocidal delta-endotoxin protein, designated Cry27A, was cloned from a Bacillus thuringiensis serovar higo strain. The Cry27A protein contained the five sequence blocks of amino acids commonly conserved in most B. thuringiensis Cry proteins. Relatively high homologies, ranging from 43.0% to 84.4%, existed between the Cry27A protein and several established classes of mosquitocidal Cry proteins (Cry4A, Cry10A, Cry19A, Cry19B, and Cry20A) in the sequence of 51 N-terminal amino acids. The complete sequence of this protein, however, showed low levels (<40%) of amino acid identity to those of the known Cry proteins. Although the expression level of the cry27A gene was low in the transformants under the control of its own promoter, the use of the cyt1A promoter resulted in high-level expression of the gene, leading to the formation of inclusions. The expressed Cry27A protein showed larvicidal activity highly specific for Anopheles stephensi, but lacked the toxicity against Culex pipiens molestus and Aedes aegypti. The results suggest that the Cry27A protein is responsible for the Anopheles-preferential toxicity of the B. thuringiensis serovar higo strain.

Amino Acid Sequence↗
PubMed2000

Larval susceptibility of the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae), to Bacillus thuringiensis H serovars isolated in Japan.

A total of 1700 Japanese strains of Bacillus thuringiensis, belonging to at least 47 H serogroups, were examined for insecticidal activity against larvae of the diamondback moth, Plutella xylostella. The high-level toxicity was associated with 612 isolates (36.0%). Of these, 608 isolates (99.3%) fell into 13 H serogroups belonging to the low-numbered H serotypes, H1-H10. Conversely, most isolates belonging to the high-numbered serotypes (>H10) had little or no larvicidal activity; only one isolate of the serovar japonensis H23 was active. P xylostella larvae were susceptible to 89.8% of the serovar morrisoni H8a:8b strains and 85.7% of galleriae H5a:5b strains. High values of 60-80% were also obtained in six serovars (thuringiensis H1, alesti H3a:3c, kurstaki H3a:3b:3c, kenyae H4a:4c, aizawai H7, and tolworhi H9), while relatively low values of <60% in two other common serovars, sotto H4a:4b and darmstadiensis H10a:10b. Five selected isolates, belonging to H serovars other than kurstaki and aizawai, were 10-60 times less toxic than the reference strain HD-1 (serovar kurstaki). Parasporal inclusion proteins of these strains were immunologically unrelated to those of the strain HD-1 and the aizawai type strain.

Animals↗
PubMed2000

Neutrophil accumulation in development gastric ulcer induced by submucosal injection of endothelin-1 in rats.

Submucosal injection of endothelin (ET)-1 induces gastric ulcer. We investigated the roles of neutrophils and adhesion molecules (intercellular adhesion molecule (ICAM)-1 and CD18) in the development of ET-1-induced ulcers in rats. Ulcers were induced by submucosal injection of ET-1. Rats were injected with anti-neutrophil serum or F(ab')2 fragments of irrelevant mouse IgG2a (control), anti-ICAM-1 antibody, or anti-CD18 antibody. Ulcer tissues were subjected to measurement of myeloperoxidase (MPO) activity, ulcer size, and immunohistochemical study. Within 3 hr, arterial vasoconstriction and vascular congestion were observed at sites of ET-1 injection. By 6 hr, vascular congestion had disappeared, and ICAM-1 expression had markedly increased in venules in deep portions of the mucosa and submucosa, accompanied by an increase in the number of CD18-positive neutrophils. By 48 hr, ulcers that extended into the submucosa had developed. In controls, MPO activity gradually increased and was maximal by 6 hr. Neutrophil depletion, and immunoneutralizing of ICAM-1 and CD18 inhibited the increase in MPO activity, and decreased ulcer sizes measured at 48 hr. In conclusion, ET-1 causes ischemia-reperfusion injury, and neutrophil accumulation after reperfusion mediated by the ICAM-1-CD18 pathway may be important in the development of ET-1-induced gastric ulcer.

Animals↗
PubMed2000

Induction of signal transduction pathways in rat gastric epithelial cells stimulated with interleukin-1beta.

BACKGROUND: Interleukin-1beta (IL-1beta) participates in cell growth, differentiation and apoptosis via activation of several kinases in a variety of cells. Mitogen-activated protein (MAP) kinases are important intermediates of the signal transduction pathway from the cell surface to the nucleus, leading to activation of transcription factors. There are no reports on the effect of IL-1beta on these pathways in gastric epithelial cells. AIM: To investigate whether IL-1beta activates MAP kinases [extracellular signal-regulated kinases (ERKs), c-Jun NH2-terminal kinases (JNKs) and p38 MAP kinase (p38 MAPK)] and nuclear factor (NF)-kappaB. a transcription factor, in gastric epithelial cells (RGM1). METHODS: The activities of ERKs and JNKs were estimated by in-gel kinase assay, and p38 MAPK activity was measured by in vitro kinase assay at various time points (0-40 min) after addition of IL-1beta (100 pg/mL) for 20 min. The activity of NF-kappaB was analysed using gel mobility shift assay at times from 0 to 4 h after addition of IL-1beta. RESULTS: Activity of ERKs was detectable at 10 min, peaked at 20 min, and continued at increased levels until 40 min. Activity of both JNKs and p38 MAPK were detectable during 5-20 min, and then decreased within 40 min. Activation of NF-kappaB occurred at 30 min, and increased activity continued for 6 h. Interleukin-1beta activated MAP kinases and NF-kappaB in RGM1 cells. CONCLUSION: The activation induced by this cytokine may play an important role in the initiation of the inflammatory process in gastric mucosa.

Animals↗
PubMed2000

In vitro cytotoxicity of non-cyt inclusion proteins of a Bacillus thuringiensis isolate against human cells, including cancer cells.

A soil isolate designated 90-F-45-14, belonging to Bacillus thuringiensis serovar dakota (H15), was examined for characterization of in vitro cytotoxicity, associated with parasporal inclusion proteins, against human cells. When activated with proteolytic processing, inclusion proteins of the isolate 90-F-45-14 exhibited a moderate cytotoxicity against the human uterus cervix cancer cells (HeLa) with an EC(50) value of 60.8 microg ml(-1), while showing extremely high activities on the human leukaemic T cells (MOLT-4) and the normal T cells with EC(50) values of 0.27 and 0.20 microg ml(-1), respectively. Anti-leukaemic cell activity of the 90-F-45-14 proteins was eight to nine times greater than that of the B. thuringiensis serovar israelensis proteins containing the Cyt1 protein, a broad-spectrum cytolysin. The cytopathy by the 90-F-45-14 proteins was characterized by marked cell-ballooning, while the israelensis proteins induced early breakdown of the cells due to cytolysis. Inclusions of the isolate consisted of five major polypeptides of 170, 103, 73, 40 and 32 kDa. A 100% homology was observed in the sequence of 15 N-terminal amino acids between the proteins of 170 and 103 kDa. There was no N-terminal sequence homology between 90-F-45-14 proteins and the existing Cry/Cyt proteins of B. thuringiensis. Proteolytic processing by proteinase K yielded several proteins with molecular masses ranging from 40 to 28 kDa.

Amino Acid Sequence↗
PubMed2000

Oesophageal cavernous haemangioma diagnosed histologically, not by endoscopic procedures.

Haemangioma of the oesophagus is uncommon in patients with benign oesophageal tumours. We present a patient with an oesophageal haemangioma detected during mass screening of the upper gastrointestinal tract. The patient, a 59-year-old man, had neither abdominal complaints nor a history of gastrointestinal diseases. Endoscopic examination revealed a blue-coloured submucosal tumour (approximately 3 cm in diameter) at the middle portion of oesophagus. Endoscopic Doppler ultrasonography showed an homogeneous and hypoechoic mass without blood flow in the submucosal layer of the oesophagus. However, a magnetic resonance imaging scan did not give a typical image for oesophageal haemangioma. Therefore, partial resection of the tumour was performed to obtain a differential diagnosis using the procedures of endoscopic ligation and polypectomy. Histological examination of the resected tissue showed a cavernous haemangioma in the oesophagus. This endoscopic technique may be useful for the differential diagnosis of oesophageal haemangioma.

Diagnostic Imaging↗
PubMed2000

Effect of branched-chain amino acids on the composition and cytolytic activity of liver-associated lymphocytes in rats.

BACKGROUND: Although branched-chain aminoacids (BCAA) are reported to be effective in prolongation of the mean survival time of patients with liver cirrhosis, it is not clear whether BCAA could influence the immune function in those patients. METHODS: Branched-chain amino acids were given as a supplement to carbon tetrachloride-induced cirrhotic rats, and an aminogram of the liver and kinetics of liver-associated lymphocytes (LAL) were then analysed. RESULTS: Liver cirrhosis was established at the 12th week, and glutathione S-transferase placental form (GST-P)-positive lesions, which are known to be pre-neoplastic lesions, occupied 1.72+/-0.84% of the liver at the 16th week in the controls. At this time the LAL showed an increase in the number of CD5-, CD8- and CD18-positive cells and augmentation of lectin-dependent cellular cytotoxicity (LDCC) activity. Furthermore, supplementation of BCAA increased the number of LAL, especially CD8-positive cells and natural killer cells, and augmented LDCC activity of LAL at the 16th week. The number of LAL was positively correlated with the valine concentration in the plasma and liver, and the area of GST-P-positive lesions tended to be decreased in the BCAA group. CONCLUSION: These findings suggest that BCAA administration has stimulatory effects on the local immune systems of the liver, which may have a potential to inhibit hepatocarcinogenesis. Moreover, among all amino acids valine might be an important amino acid for enhancing the immune function of LAL.

Amino Acids, Branched-Chain↗
PubMed2000

High-expression of sphingomyelin deacylase is an important determinant of ceramide deficiency leading to barrier disruption in atopic dermatitis.

We have previously demonstrated that there is abnormal expression of sphingomyelin (SM) deacylase-like enzyme in the epidermis of patients with atopic dermatitis (AD), which results in decreased levels of ceramides in their involved and uninvolved stratum corneum. For quantitation of the expression of SM deacylase in AD, we synthesized 16-(9-anthroyloxy) hexadecanoylsphingosylphosphorylcholine or [palmitic acid-14C] SM and used them as substrates to directly measure the activity of SM deacylase by detecting the release of labeled free fatty acid. Direct enzymatic measurements demonstrated that stratum corneum from lesional forearm skin (volar side) of AD patients has an extremely high SM deacylase activity that is at least five times higher than in the stratum corneum from healthy controls. In stratum corneum from nonlesional skin of AD patients, SM deacylase activity is still at least three times higher than in healthy controls. In contrast, stratum corneum from contact dermatitis patients shows levels of SM deacylase similar to healthy controls. In extracts of whole epidermis biopsies from AD patients, SM deacylase activities are significantly (3-fold) increased over healthy controls in the particulate fraction, whereas there is no significant difference in the activity of sphingomyelinase between AD and healthy control. In peripheral blood lymphocytes of AD patients, there is no increase in activity compared with healthy controls, indicating a possibility that the high expression of SM deacylase is highly associated with the skin of AD patients. These findings suggest that, in contrast to changes in sphingolipid metabolism due to aging, the hitherto undiscovered enzyme SM deacylase, is highly expressed in the epidermis of AD patients, and competes with sphingomyelinase or beta-glucocerebrosidase for the common substrate SM or glucosylceramide, which leads to the ceramide deficiency of the stratum corneum in AD.

Adolescent↗
PubMed2000

Arteriovenous malformation of the penis in an infant.

Arteriovenous malformations (AVMs) are common benign lesions in infancy, although they are rare in the genitourinary region. The authors report on a 2-year-old boy with a penile AVM. At presentation, there was venous dilatation and tortuosity of the prepuce without ulceration, which had been recognized at 1 year of age. Left internal iliac arteriography showed early venous filling leading to the diagnosis of AVM. Surgical excision was performed at age 2. The postoperative course was uneventful. At the 6-month follow-up, there was no evidence of recurrence. This is the first report of a penile AVM that was successfully treated by surgical excision.

Arteriovenous Malformations↗
PubMed2000

Wild type ApoA-II gene does not rescue senescence-accelerated mouse (SAMP1) from short life span and accelerated mortality.

Biochemical and genetic data suggest that the Apoa2c allele of the apolipoprotein A-II gene causes severe senile amyloidosis (AApoAII) in SAMP1, a mouse model for accelerated senescence. We analyzed the effects of replacement of Apoa2c in SAMP1 mice with non-amyloidogenic Apoa2b on amyloidosis, lipoprotein metabolism, and progression of senescence using a congenic strain, P1.R1-Apoa2b, which has the Apoa2b chromosome region of SAMR1 in the genome of SAMP1. Age-associated amyloid deposition was not observed, but plasma concentrations of apoA-II protein and HDL-cholesterol decreased with age in P1.R1-Apoa2b. P1.R1-Apoa2b showed lower scores of senescence than did SAMP1. However, the life span and mortality rate doubling time were similar in P1.R1-Apoa2b and SAMP1. These results suggest that replacement of Apoa2c with non-amyloidogenic Apoa2b does not rescue SAMP1 mice from a short life span and accelerated mortality.

Aging↗
PubMed2000

Serum lipid concentrations and mean life span are modulated by dietary polyunsaturated fatty acids in the senescence-accelerated mouse.

The senescence-accelerated mouse (SAMP8) is an animal model used in studies of aging. This study was undertaken to investigate the effects of dietary PUFA on longevity (Experiment 1) and serum lipid concentrations (Experiment 2) in SAMP8 mice. Male mice were fed either an (n-3) PUFA-rich (9 g/100 g perilla oil) or an (n-6) PUFA-rich (9 g/100 g safflower oil) diet beginning at 6 wk of age. Experiment 1: The groups did not differ in body weight gain, but those fed perilla oil had significantly lower scores of senescence relative to those fed safflower oil (P<0.05). The mean life span of mice fed perilla oil was 357+/-21 d and of those fed safflower oil, 426+/-24 d (P<0.05). Pathological studies revealed that the incidence of tumors was significantly lower in the perilla oil group than in the safflower oil group (P<0.05). Approximately half the mice fed perilla oil had died after 10 mo, and the direct causes closely connected with death could not be specified. Experiment 2: The serum total cholesterol, HDL cholesterol, triglyceride and phospholipid concentrations were significantly lower in the perilla oil group than in the safflower oil group (P<0.01). A marked decrease of serum HDL cholesterol and apolipoprotein A-II (ApoA-II)concentrations in advanced age were observed in the mice fed perilla oil (P<0.01). Ten-month-old mice fed perilla oil had a significantly greater ratio of apolipoprotein A-I (ApoA-I) to ApoA-II than those fed safflower oil. Separation of HDL subfractions revealed that the smaller HDL species were much more abundant than the larger HDL species in both dietary oil groups. These findings suggest that dietary (n-3) and (n-6) PUFA differ in their effects on serum lipid metabolism which may modulate the mean life span of SAMP8 mice fed each dietary oil.

Aging↗
PubMed2000

Molecular cloning and characterization of a new neuron-specific homologue of rat polypyrimidine tract binding protein.

Cancer-associated retinopathy (CAR) is a rare form of retinal degeneration and also one of the paraneoplastic neurologic disorders. Sera of CAR patients usually contain high titers of antibodies against retinal proteins, and CAR is believed to be an autoimmune disease. Using serum from a CAR patient as a molecular probe, a homologue of the polypyrimidine tract-binding protein (PTB) was isolated from a cDNA library of rat neonatal retina. This homologue, named PTB-like protein (PTBLP), encodes a 532 amino acid residue protein and has 73.5 and 68.8% homology with PTB and with a regulator of differentiation 1, respectively. Functional domains in the PTB, such as nuclear localization signals and four RNA recognition motifs (RRMs), were highly conserved. The expression of PTBLP mRNA was observed in the retina and brain but not in liver, kidney, spleen, or lung. The expression of PTBLP protein in rat retina was distributed in most of the cells in the ganglion cell layer and some cells in the inner nuclear layer. The PTBLP protein was localized in the nuclei of these cells. These results suggest that PTBLP is a new member of the PTB gene family and a neuron-specific homologue.

Amino Acid Sequence↗
PubMed2000

Histological estimation of the efficacy of endoscopic laser coagulation therapy for diffuse antral vascular ectasia.

We present the case of a 72-year-old woman with successful control of repeated episodes of bleeding from diffuse antral vascular ectasia (DAVE) by laser coagulation therapy. In addition to DAVE, the patient also suffered from severe iron deficiency anaemia (due to recurrent bleeding), liver cirrhosis, and huge tumours of hepatocellular carcinoma (HCC). She was referred from another hospital after failure to stop her bleeding episodes. Endoscopic examination revealed diffuse speckled telangiectasia over most of the stomach (from antrum to the upper portion of the body) and large numbers of blood clots. The patient had received repeated blood transfusions, haemostatic drugs, and H2 receptor antagonists at the other hospital, without improvement of the repeated bleeding. She underwent three sessions of endoscopic laser coagulation therapy for the lesions at our hospital after the final diagnosis of DAVE had been made based on the characteristic histological findings of biopsied specimens. This treatment improved her general condition and stopped the bleeding from the gastrointestinal tract even without fasting. Unfortunately, however, her liver function gradually worsened due to HCC and previous massive bleeding, and she finally died of liver failure three months after the last laser session. Autopsied specimens obtained from the patient's stomach revealed that macroscopic diffuse speckled telangiectasia and microscopic typical vasodilatation in mucosal and submucosal layers of gastric tissue had disappeared in the treated areas but not all portions of the DAVE lesion. These histological findings for the treated areas, in addition to the clinical improvement of bleeding, suggest that endoscopic laser coagulation therapy may be useful and one of the first choices in treatment for DAVE.

Aged↗
PubMed2000

Marked enhancement by fish meal of Helicobacter pylori-induced gastritis in Mongolian gerbils.

In a search for dietary factors influencing Helicobacter pylori-induced gastritis, the effects of fish meal in the diet were examined in Mongolian gerbils. When a conventional diet containing 10% fish meal was given to Mongolian gerbils for 4 weeks after inoculation of H. pylori, edematous thickening with severe neutrophil and mononuclear cell infiltration in both the mucosa and submucosa was observed in the glandular stomach of 19 out of the 20 animals, and hemorrhagic spots were evident in 11 cases. These gastric lesions were enhanced by a 20% fish meal supplement, and edema and hemorrhage in the gastric mucosa were observed in 19 and 17 out of 20 animals, respectively. Although almost the same levels of viable bacteria were detected independent of the diet, edema and hemorrhage were seen in only 2 and 1 of 20 gerbils fed a diet containing 10% casein, instead of 10% fish meal, respectively. Neither edema nor hemorrhage was observed in 10% beef diet animals. These results suggest that fish meal contains factors which greatly enhance H. pylori-induced gastritis in Mongolian gerbils. Since the incidences of gastritis and gastric cancer are very high throughout the world, it is very important to identify these gastritis-enhancing factors.

Animals↗
PubMed2000

Parasporin, a human leukemic cell-recognizing parasporal protein of Bacillus thuringiensis.

An unusual property, human leukemic cell-recognizing activity, associated with parasporal inclusions of a noninsecticidal Bacillus thuringiensis soil isolate was investigated, and a protein (named parasporin in this study) responsible for the activity was cloned. The parasporin, encoded by a gene 2,169 bp long, was a polypeptide of 723 amino acid residues with a predicted molecular weight of 81, 045. The sequence of parasporin contained the five conserved blocks commonly found in B. thuringiensis Cry proteins; however, only very low homologies (<25%) between parasporin and the existing classes of Cry and Cyt proteins were detected. Parasporin exhibited cytocidal activity only when degraded by proteases into smaller molecules of 40 to 60 kDa. Trypsin and proteinase K activated parasporin, while chymotrypsin did not. The activated parasporin showed strong cytocidal activity against human leukemic T cells (MOLT-4) and human uterus cervix cancer cells (HeLa) but not against normal T cells.

Amino Acid Sequence↗