Biomedical subjects

K Kubota

Publications and source records attributed to K Kubota.

At least 19 recordsLinked to original sources

PubMed1995

Calcium destabilises Drosophila cactus protein and dephosphorylates the dorsal transcription factor.

The Drosophila cactus and dorsal proteins are required for the development of embryonic dorso-ventral polarity and probably also for the innate immune response of the insect. Like their mammalian counterparts (the cytoplasmic anchor protein I kappa B and the rel/NF kappa B transcription factors) cactus and dorsal are regulated at the level of nuclear localisation. We showed previously that increased intra-cellular calcium levels induced by the ionophore ionomycin can activate dorsal/cactus complexes in the Drosophila cell line SL2. In order to study further the activation of dorsal/cactus complexes by calcium, we have prepared a cell line (SLDL) in which dorsal is expressed constitutively. In this paper we show that in SLDL cells ionomycin induces a rapid destruction of cactus and dephosphorylation of dorsal. These results suggest a role for the protein phosphatase calcineurin in calcium mediated activation of dorsal/cactus complexes. They also indicate that in the resting cell constitutive phosphorylation of dorsal is in equilibrium with calcium dependent dephosphorylation.

Amino Acid Sequence↗

PubMed1995

The dorsal protein enhances the biosynthesis and stability of the Drosophila I kappa B homologue cactus.

The cactus and dorsal proteins are Drosophila homologues of mammalian I kappa B cytoplasmic anchor proteins and rel/NF kappa B transcription factors respectively. They are required for the generation of embryonic dorsoventral polarity and probably at later developmental stages for an innate immune response. In this paper we report on the properties of SLDL, a derivative of the SL2 cell line in which dorsal is expressed constitutively. In SLDL cells biosynthesis of cactus protein is stimulated by approximately 4-fold when compared with SL2 cells. Enhanced biosynthesis of cactus protein cannot be explained solely on the basis of increased expression of the cactus gene as the level of the corresponding mRNA is only 2-fold higher than in SL2 cells. On the basis of these findings we propose that free cytoplasmic dorsal protein is able, directly or indirectly to stimulate translation of the cactus mRNA. Such an arrangement would enable the dorsal protein to be buffered in the cytoplasm of the resting cell over a wide range of concentrations. We also show here that subsequent to biosynthesis the cactus protein is either rapidly degraded or incorporated into complexes with dorsal. Protein that does not associate with dorsal has a half-life of approximately 40 min whereas that which is incorporated into complexes is very stable, having a half life in excess of 24 h. The complexed cactus protein is acted on by protein kinases which generate distinct phophorylated isoforms.

Animals↗

PubMed1995

Wild type and constitutively activated forms of the Drosophila Toll receptor have different patterns of N-linked glycosylation.

Toll is a Drosophila membrane protein related in sequence to the mammalian platelet glycoprotein 1B and to the interleukin-1 receptor. It mediates a signal transduction pathway leading to the development of dorsoventral polarity in the Drosophila embryo. In this paper we show that a constitutively activated mutant receptor, Toll10B, is processed into a distinct isoform of slower electrophoretic mobility when compared with the wild type molecule in both cell lines and the embryo. The wild type protein can also be processed into this form if over-expressed but in the embryo is present as the smaller species. We show that the decrease in the mobility of Toll10B and over-expressed wild type receptors is caused by altered patterns of N-linked glycosylation and that both forms are secreted to the cell surface. On the basis of these results, we propose that the Toll10B receptor is unable to associate with a limiting co-factor which when bound directly or indirectly masks supplementary N-linked glycosylation sites.

Animals↗

PubMed1995

Carboxy-terminal degradation of peptides using perfluoroacyl anhydrides. A C-terminal sequencing method.

An accurate carboxy-terminal sequencing method has long been sought to complement the Edman degradation procedure for amino-terminal amino acid sequence analysis. The method presented here is a unique and simple method to partly fulfill the needs. Exposure of a polypeptide to perfluoroacyl anhydride vapor at -20 degrees C for 0.5-1 h causes sequential chemical degradation of the molecule from the C-terminus. Fast-atom-bombardment mass spectrometric analysis of the resultant mixture of C-terminally truncated molecules permits the determination of the C-terminal sequence by simple calculation of the mass differences in molecular ions. Experiments suggested that this C-terminal degradation proceeds by active intermediates such as oxazolone at the C-terminal carboxyl residues.

Acetic Anhydrides↗

PubMed1995

Suppression of ischemia-reperfusion injury in murine models by neopterins.

We investigated the effects of D-neopterin (NP) and its reduced form, 5,6,7,8-tetrahydro-D-neopterin (NPH4), in two models of ischemia-reperfusion injury, i.e., ischemic paw edema in mice and gastric ischemia in rats. In ischemic paw edema, iv administration of either NP or NPH4 more potently inhibited the increase of paw thickness after release from ischemia than did administration of superoxide dismutase plus catalase or allopurinol. In gastric ischemia, NP and NPH4 also significantly suppressed the formation of gastric mucosal erosions. Lipid peroxidation in the stomach was increased by ischemia-reperfusion treatment, and the increase was inhibited by the administration of NP or NPH4. The minimum dose of NPH4 required to suppress the gastric ischemic injury in this experiment was 0.3 mg/kg of body weight. These results suggest that neopterin may be effective as a protective agent against ischemia-reperfusion injury, in which active oxygen species are believed to play a major role.

Allopurinol↗

PubMed1995

Vasodilation-related adverse events in diltiazem and dihydropyridine calcium antagonists studied by prescription-event monitoring.

The incidence of vasodilation-related events (flushing, headache, dizziness and oedema) was determined in a total of 37,670 patients treated with diltiazem, nicardipine, isradipine or amlodipine and studied by Prescription-Event Monitoring between 1984 and 1991. Event rates are expressed as the percentage of patients who experienced these events during the six months after the first prescription. The rates for all these events with the newer vasoselective dihydropyridines (nicardipine, isradipine and amlodipine) were higher than those with diltiazem. Among the three dihydropyridines, there were large individual differences in the rates. With nicardipine, the frequency of each of the four vasodilation-related events were similar to one another (approximately 3%). With isradipine, the rates were also similar to one another but all were approximately twice those measured in the nicardipine study (approximately 6%). These differences may have been due to confounding factors such as the publicity about adverse drug reactions, the indication for use by individual patients or the doses actually being used at the time the event occurred. With amlodipine, in contrast, the rate for oedema was two to four times larger than the rates for flushing, headache or dizziness.

Adult↗

PubMed1995

Local injection of bicuculline into area 8 and area 6 of the rhesus monkey induces deficits in performance of a visual discrimination GO/NO-GO task.

While performing a symmetrically reinforced visual discrimination GO/NO-GO task, five monkeys were injected with a GABAA antagonist, bicuculline methiodide (BMI), into Brodmann's area 9, 8, 6, or 4. The task consisted of five periods: START, OFF, CUE, RESPONSE, and an inter-trial interval. The monkey was trained to make either the GO response (lever release) or the NO-GO response (continued pressing of the lever), depending on the color of the cue, during the RESPONSE period. Analysis was limited to 102 sites in which muscle convulsions of the forelimb and/or shoulder did not result from BMI injections. Errors in performance increased 10-60 min after injection into 10 of 33 sites in area 9, 9 of 25 sites in area 8, 20 of 34 sites in area 6, and 2 of 10 sites in area 4. The number of trials finished in a 120-min session decrease. Injections induced PRE-RESPONSE errors (release of the lever in either the OFF or CUE periods), GO RESPONSE errors (failure to release the lever when signaled), and NO-GO RESPONSE errors (release of the lever despite a signal not to release). The results suggest that both areas 8 and 6 are involved in correct performance of the GO/NO-GO task.

Animals↗

PubMed1995

Effects of radiotherapy on the cellular uptake of carbon-14 labeled L-methionine in tumor tissue.

In order to examine in vivo effects of irradiation on tumor uptake of L-[methyl-11C]methionine at a cellular level, the distribution of L-[methyl-14C]methionine (Met) in a rat AH109A tumor model was investigated using microautoradiography. Silver grain density of tumor cell layer decreased rapidly within the first day after 20 Gy of irradiation, and continued to fall during day 2. Grain density of granulation tissue was 25% of tumor cells and was unchanged after irradiation. Macrophages and necrotic tissue showed low grain density and a small post-irradiation decrease. One day after irradiation, tumor cell showed giant cell formation and decreased cell density per unit area. The number of grains was greater in giant tumor cells than in non-irradiated tumor cell. Rapid response of Met uptake by tumor cells without a significant uptake by granulation tissue and macrophages suggest that 11C-Met is a suitable tracer for monitoring tumor radiotherapy with positron emission tomography.

Animals↗

PubMed1995

How should polypoid lesions of the gallbladder be treated in the era of laparoscopic cholecystectomy?

BACKGROUND: Definitive criteria for choosing the most appropriate treatment for each type of polypoid lesion of the gallbladder (PLG) have yet to be established. METHODS: The shapes, sizes, echo patterns, and echogenicities of PLGs that had been evaluated by means of ultrasonography in 72 patients who had undergone resective surgery were analyzed retrospectively to elucidate the ultrasonic characteristics of polypoid cancers and to establish criteria for selecting the most suitable treatment such as laparoscopic cholecystectomy for each type of PLG. RESULTS: Histologic examinations showed cholesterol polyps in 47 patients, adenomas in 8, cancers in 16, and an inflammatory polyp in 1. The diameters of 61% of the benign PLGs were less than 10 mm, whereas those of 88% of the cancers were more than 10 mm; 80% of the former were pedunculated and 56% of the latter were sessile. Seven of eight early-stage cancers had diameters less than 18 mm, whereas those of all eight more advanced cancers were greater than 18 mm. Five of the eight early-stage cancers were pedunculated, and six of the eight more advanced cancers were sessile. Cholecystectomy with or without full-thickness dissection were main surgical procedures used to resect benign PLGs and early-stage cancers, whereas cholecystectomy with partial liver resection was used for more advanced cancers. Laparoscopic cholecystectomy was performed in the recent 34 patients, four of whom had early-stage cancers. CONCLUSIONS: A PLG with a diameter of less than 18 mm is a potential early-stage cancer and therefore can be resected by laparoscopic cholecystectomy with full-thickness dissection. However, when cancer invades the subserosal layer or beyond, a second-look operation is necessary. A PLG with a diameter of greater than 18 mm may be an advanced cancer and should be removed by using cholecystectomy with partial liver resection or a more extended procedure with lymph node dissection.

Adenocarcinoma↗

PubMed1995

Appraisal of intraoperative ultrasonography during laparoscopic cholecystectomy.

BACKGROUND: The usefulness of intraoperative ultrasonography during laparoscopic cholecystectomy (LC) has yet to be evaluated fully. METHODS: In 50 patients who underwent LC, the intraoperative ultrasonography findings were compared with those of preoperative ultrasonography, intraoperative cholangiography, and histology, and then its usefulness for examining anatomic relationships in the hepatoduodenal ligament, detecting bile duct stones, diagnosing gallbladder polyps and abnormally thickened walls, and determining the propriety of LC was appraised. RESULTS: The preoperative ultrasonography diagnoses were gallstones in 38 patients, polyps in 10, and cancer and adenomyomatosis in one each. In four patients endoscopic retrograde cholangiography showed bile duct stones. In all 50 patients intraoperative ultrasonography was useful for examining the anatomic relationships between the bile duct and vessels, such as the portal vein and hepatic artery, and showing the presence or absence of bile duct stones. On the basis of the intraoperative ultrasonography findings, gallstones were diagnosed in 38 patients, in five of whom bile duct stones were shown clearly, cholesterol polyps in eight, early-stage cancer or adenoma in two, and adenomyomatosis in two, and subsequently LC was performed. Histologic diagnoses of cholesterol polyps were made in eight of ten patients with polyps, and intramucosal cancer and an inflammatory polyp in one each. In one patient with a preoperative diagnosis of cancer the apparently elevated flat lesion was found to be partial thickening of the gallbladder wall, which was diagnosed as adenomyomatosis, and LC was chosen as the operative procedure. CONCLUSIONS: Intraoperative ultrasonography during LC is useful for detecting bile duct stones, diagnosing gallbladder polyps and abnormally thickened walls, and deciding whether LC is adequate for resection of the gallbladder.

Adult↗

PubMed1995

Segmental occlusion of the pancreatic duct with prolamine to prevent fistula formation after distal pancreatectomy.

OBJECTIVE: The authors used prolamine (Ethibloc, Ethicon GmBH, Norderstedt, Germany) for segmental obstruction of the pancreatic duct to prevent pancreatic fistula development after distal pancreatectomy combined with total gastrectomy for gastric malignancies. SUMMARY BACKGROUND DATA: Although the initial clinical application of prolamine was pancreatic duct obstruction for patients with pancreatitis and undergoing pancreatic transplantation and pancreaticoduodenectomy for pancreatic cancer, there are no reports on prevention of pancreatic fistula formation after distal pancreatectomy. METHODS: Prolamine (0.2 mL) was injected into the distal segment of the main duct in the remaining pancreata of 51 patients. Small pancreatic ducts on the cut surface, from which prolamine extravasates, were closed by ligation, the main duct was ligated doubly, and the transected pancreatic margin was closed 15 minutes after phenylpropanolamine hydrochloride injection. RESULTS: No patient developed a pancreatic fistula or the complication of arterial bleeding due to prolonged infection. CONCLUSION: Segmental obstruction of the pancreatic duct with prolamine is useful for preventing pancreatic fistula development after distal pancreatectomy.

Amylases↗

PubMed1995

A time correlation study between reflectance spectroscopic cutaneous vasoconstriction and plasma corticosteroid concentration.

Although cutaneous vasoconstriction assays are used as a primary screen for ranking the in vivo efficacy of new corticosteroids and in vivo human drug delivery studies, little is known about the relationship between the blanching reaction and corticosteroid tissue or plasma concentrations. We measured cutaneous vascular reactions in five volunteers, using an improved reflectance spectroscopic method, and a sensitive radioimmunoassay technique was employed to measure plasma betamethasone concentrations. Using a specially developed betamethasone-17-valerate patch prepared in BIO-PSA, constant corticosteroid release was ensured, and correlations between cutaneous blanching and plasma corticosteroid concentrations were calculated. Maximal skin blanching was documented 12 h post-application, whereas plasma corticosteroid concentrations peaked later, at 32 h post-application, when a paradoxical telangiectatic vasodilatation occurred. At 72 h post-application, when the plasma corticosteroid concentration was still above the 12 h level, this paradoxical vasodilatation was maximal. The corticosteroid-induced vascular reactions were mainly due to arterial haemoglobin (Oxy Haem), and both vasoconstriction and vasodilatation were related to changes in Oxy Haem. Our results suggest a dual, probably both time and concentration related, interaction between corticosteroids and dermal vessels in which lower concentrations at 6-12 h exposure caused vasoconstriction, but as the exposure time increased (> or = 24 h) paradoxical vasodilatation was induced, although plasma corticosteroid concentrations were still rising.

Adult↗

PubMed1995

Acquired total immunoglobulin G deficiency in a patient with primary biliary cirrhosis.

A 38-year-old Japanese woman was hospitalized for susceptibility to respiratory tract infections. Clinical examinations revealed asymptomatic primary cholestasis, abnormally elevated immunoglobulin M (IgM) and antimitochondrial antibody, being consistent with asymptomatic primary biliary cirrhosis. Three years later her serum immunoglobulin G (IgG) decreased remarkably, whereas other immunoglobulins were unchanged. Immunological examinations on the peripheral blood lymphocytes demonstrated spontaneous over-synthesis of serum IgM and decreased synthesis of IgG due to abnormal function of both T and B cells. Our case suggests a new possible association between primary biliary cirrhosis and IgG deficiency.

Adult↗

PubMed1995

Mnemonic firing of neurons in the monkey temporal pole during a visual recognition memory task.

1. We examined single-neuronal activity in the temporal pole of monkeys, including the anterior ventromedial temporal (VMT) cortex (the temporopolar cortex, area 36, area 35, and the entorhinal cortex) and the anterior inferotemporal (IT) cortex, during a visual recognition memory task. In the task, a trial began when the monkey pressed a lever. After a waiting period, a visual sample stimulus (S) was presented one to four times on a monitor with an interstimulus delay. Thereafter, a new stimulus (R) was presented. The monkeys were trained to remember S during the delay period and to release the lever in response to R. Colored photographs of natural objects were used as visual stimuli. 2. About 70% of the recorded neurons (225 of 311) responded to at least one of the Ss tested. Thirty percent of these neurons (68 of 225) continued to fire during the subsequent delay periods. In 75% of these neurons (51 of 68), the firing during the delay period strongly correlated with the response to S. 3. The discharge rate during the delay period did not correlate with the monkey's eye movements, pressing or releasing of the lever, or the reaction time. 4. If the monkey erroneously released the lever in response to S or during the delay period, the firing disappeared after the erroneous lever release. If the monkey failed to release the lever in response to R, the firing persisted even after R was withdrawn. The discharge rate in incorrect trials was comparable with that in correct trials. The neurons were considered to fire for as long as the memory of S was necessary. 5. Firing persisted even when an achromatic version or half (even a portion) of S was presented, indicating that the color, a particular portion, or the entire shape of S was not always necessary to elicit firing. 6. An S that elicited firing during the delay period invariably elicited a visual response. Neurons that fired during the delay period showed a higher stimulus selectivity than other visually responsive neurons in the anterior VMT cortex. Thus neurons that fire during the delay period represent a subgroup of visually responsive neurons that are selectively tuned to a certain stimulus. 7. More neurons fired during the delay period in the anterior VMT cortex than in the anterior IT cortex. 8. We conclude that firing during the delay period by neurons in the temporal pole reflects the short-term storage of visual information regarding a particular S.

Animals↗

PubMed1995

Phase II study of concurrent radiotherapy and chemotherapy for unresectable stage III non-small-cell lung cancer. Southern Osaka Lung Cancer Study Group.

PURPOSE: To evaluate the response rate, toxicity, and 2-year survival rate of concurrent radiotherapy and chemotherapy for unresectable stage III non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Between July 1989 and October 1990, 65 patients with histologically or cytologically proven unresectable stage III NSCLC without T3N0-1M0 disease were entered onto this study. Sixty-one patients were eligible for response, survival, and toxicity analysis. Chemotherapy consisted of vindesine (3 mg/m2 on days 1, 8, 29, and 36), cisplatin (100 mg/m2 on days 1 and 29), and mitomycin (8 mg/m2 on days 1 and 29). Radiotherapy was administered for 3 weeks (2 Gy given 13 times, five fractions per week), followed by 10-day rest periods and then the previous schedule of radiotherapy repeated for 3 weeks. RESULTS: Of 61 eligible patients, 53 (86.9%) had a partial response (PR). The median response duration was 39.1 weeks (range, 8.4 to 163+). The median survival time was 16 months and the 2-year survival rate was 36.7%. Of 53 responding patients, 10 (16.4%) are alive and disease-free after 2 years. The major toxicity was leukopenia (> or = grade 3, 95%). Other toxicities of > or = grade 3 included thrombocytopenia (45%), anemia (28%), nausea/vomiting (16%), fever (11%), and esophagitis (6%). Treatment-related death occurred in two patients. One patient died of pulmonary toxicity (interstitial pneumonitis) and the other of esophagobronchial fistula with pulmonary infection. CONCLUSION: Concurrent radiotherapy plus chemotherapy with mitomycin, vindesine, and cisplatin (MVP) can be safely administered to patients with stage III NSCLC, with excellent response rates and 2-year survival rates.

Adult↗

PubMed1995

Effect of 5,6,7,8-tetrahydroneopterin on the bovine endothelial cell injury induced by cumene hydroperoxide.

Neopterin is an 2-amino-4-hydroxypteridine derivative and a precursor of biopterin, which is derived from guanosine triphosphate. Previously, we have reported that 5,6,7,8-tetrahydroneopterin (NPH4), a reduced form of neopterin, possesses an antioxidant activity in various systems. In this study, we investigated the activity in more detailed manner and discussed the possible applications of this antioxidant. Analysis by electron spin resonance spectrometry indicated that NPH4 scavenged superoxide anion radicals and hydroxyl radicals as well. Moreover, NPH4 protected the rat brain homogenate from autoxidation. Next, we examined the effect of NPH4 on the cell injury induced by cumene hydroperoxide (CHP) in cultured bovine artery endothelial cells. The activity of lactate dehydrogenase, a marker enzyme of cell injury, was elevated by CHP in a dose-dependent manner, and this elevation was dose-dependently suppressed by NPH4. The elevation of lipid peroxide content was also inhibited by NPH4 in the same fashion. These data suggest that NPH4 would be effective against various diseases whose pathogenesis is active oxygen-related.

Animals↗

PubMed1995

Overview of effects of electrical stimulation on osteogenesis and alveolar bone.

One endpoint of periodontal therapy is to regenerate structure lost to periodontal disease. Periodontal regeneration requires both formation of a new connective tissue attachment to the tooth and formation of alveolar bone. Several procedural advances may support regeneration of the attachment, however, regeneration of alveolar bone does not occur consistently. Therefore, factors which stimulate bone repair are areas for research in periodontal reconstructive therapy. Effects of cytokines or growth factors on bone repair are examples of such areas. Another one is electrical stimulation which naturally occurs in bone, and as such bone may be particularly susceptible to electrical therapy. This overview describes the potential of electrical stimulation for bone regeneration and applications in alveolar and periodontal research.

Alveolar Bone Loss↗

PubMed1995

Periodontal repair in dogs: recombinant human bone morphogenetic protein-2 significantly enhances periodontal regeneration.

This study evaluated bone and cementum regeneration following periodontal reconstructive surgery using recombinant human bone morphogenetic protein-2 (rhBMP-2) in six beagle dogs. Surgically created mandibular supraalveolar premolar tooth defects in contralateral jaw quadrants were randomly assigned to receive rhBMP-2 or control vehicle. Clinical defect height was prepared to 5 mm. rhBMP-2 was applied with synthetic bioerodable particles and autologous blood using 20 micrograms rhBMP-2 per 100 microliters implant volume. Flaps were advanced to submerge the teeth and sutured. The dogs were sacrificed 8 weeks postsurgery. Histometric recordings included defect height, height and area of alveolar bone regeneration, height of cementum regeneration, root resorption, and ankylosis. Group means, standard deviations, and P values are shown (Student t test; n = 6). Histometric defect height for rhBMP-2 and control defects was 3.7 +/- 0.3 and 3.9 +/- 0.4 mm, respectively (P = 0.446). Height of alveolar bone regeneration amounted to 3.5 +/- 0.6 and 0.8 +/- 0.6 mm for rhBMP-2 and control defects, respectively (P = 0.000). Corresponding values for bone area were 8.4 +/- 4.5 and 0.4 +/- 0.5 mm2, respectively (P = 0.006). Cementum regeneration was observed in all experimental defects (17/17) and in 15 out of 17 controls, averaging 1.6 +/- 0.6 and 0.4 +/- 0.3 mm for rhBMP-2 and control defects, respectively (P = 0.005). Small amounts of root resorption were seen in rhBMP-2 defects, whereas controls exhibited substantial resorption (0.2 +/- 0.1 and 1.1 +/- 0.3 mm, respectively; P = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Alveolar Bone Loss↗