Biomedical subjects

K Fukuda

Publications and source records attributed to K Fukuda.

At least 361 records · Page 20Linked to original sources

PubMed1997

Clinical significance of asymptomatic sinus abnormalities on magnetic resonance imaging.

OBJECTIVE: To investigate the prevalence of abnormalities of the paranasal sinus detected by magnetic resonance imaging (MRI) in asymptomatic subjects. DESIGN: Prospective study. SETTING: Outpatient clinic. PATIENTS: A total of 325 patients who underwent MRI for suspected intracranial disease. Of those, 257 patients lacked nasal or sinus symptoms. RESULTS: Sinus abnormalities were seen on MRI in 153 (47.1%) of 325 patients, including 107 (41.6%) of the 257 asymptomatic patients. Subjects older than 50 years had a significantly higher frequency of sinus abnormalities on MRI (49.8%) vs those younger than 50 years (39.5%) (P < .05). The maxillary sinus abnormality was observed in 99 patients (38.5%) and the ethmoid sinus abnormality was observed in 52 (20.2%) (P < .01). The most common abnormality was mucosal thickening in the maxillary and ethmoid sinuses. CONCLUSION: A high prevalence of sinus abnormalities was detected in asymptomatic subjects on MRI.

Ethmoid Sinus↗

PubMed1997

Echocardiographic characteristics and causal mechanism of physiologic mitral regurgitation in young normal subjects.

BACKGROUND: It has become evident that mitral regurgitation (MR) is not uncommon in healthy subjects, and Doppler color flow mapping is a technique that imparts important information relevant to its detection. HYPOTHESIS: Using transthoracic echocardiography, this study evaluated the mechanism of physiologic MR in young normal subjects using transthoracic echocardiography. METHODS: The study population consisted of 48 young normal subjects (mean 21 +/- 5 years) with MR (physiologic MR group), 40 age-matched young normal subjects (mean 20 +/- 5 years) without MR (control group), 45 patients (mean 41 +/- 15 years) with mitral valve prolapse with MR (MVP group), and 27 patients (mean 59 +/- 13 years) with ruptured chordae tendineae (rupture group). RESULTS: Men were predominant in the rupture group, whereas there were no significant gender differences in the other three groups. Left ventricular end-diastolic dimension and left atrial systolic dimension were slightly smaller in the physiologic MR group than in the control group, but were significantly smaller than those in the MVP and rupture groups. The ratio of the maximum anteroposterior diameter to the maximum transverse diameter on chest radiography and the ratio of the short- to long-axis diameter of the left ventricular cavity at end diastole, determined from two-dimensional short-axis echocardiogram, were significantly lower in the physiologic MR group than in the other three groups. Mitral regurgitation occurred more frequently at the posteromedial commissural site in the physiologic MR and MVP groups, whereas there was no preference for location in the rupture group. Early systolic MR was often observed in the physiologic MR group, whereas pansystolic MR was common in the MVP and rupture groups. CONCLUSION: As a causal mechanism for physiologic MR detected in young normal subjects, "flattening" of the thorax during growth may cause morphologic abnormalities of the left atrial and ventricular cavities, resulting in spatial imbalance of the mitral complex and resulting in malcoaptation of the valve.

Adult↗

PubMed1997

Telomerase activity in gynecologic tumors.

The standard telomeric repeat assay protocol (TRAP) was used to examine telomerase activity in 16 ovarian tumors, 16 cervical carcinomas, 4 uterine tumors, and 3 vaginal tumors. Telomerase activity was detected in 95% of these tumors, 88% of ovarian malignancies, and 100% of cervical, endometrial, and vaginal malignancies. In contrast, telomerase activity was not evident in normal tissues or in benign proliferative lesions, such as leiomyomas, condyloma acuminata, and simple endometrial hyperplasia. These results suggest that telomerase activation is associated with immortalization or malignant transformation of gynecologic tumors.

Adolescent↗

PubMed1997

Hyaluronic acid inhibits interleukin-1-induced superoxide anion in bovine chondrocytes.

OBJECTIVE: To examine the effect of hyaluronic acid (HA) on the induction of superoxide anion by IL-1 in chondrocytes. MATERIALS AND METHODS: Bovine articular chondrocytes were treated with different concentrations of IL-1. A chemiluminescent probe (L-012) was added to the medium and chemiluminescence detection was used to measure super oxide anion. RESULTS: IL-1 caused induction of superoxide anions in a dose-dependent manner. HA (10-100 micrograms/ml) countered superoxide induction caused by 20 ng/ml of IL-1. CONCLUSIONS: HA can afford protection against cartilage degradation, probably acting as a free-radical scavenger.

Animals↗

PubMed1997

Cultured retinal pericytes stimulate in vitro angiogenesis of endothelial cells through secretion of a fibroblast growth factor-like molecule.

Interaction between cultured endothelial cells (EC) and pericytes (PC) was studied in vitro to clarify the mechanism of diabetic proliferative retinopathy. Conditioned medium (CM) from retinal PC strongly increased the proliferation and moderately stimulated migration of retinal EC. Moreover, CM from PC caused stimulation of angiogenesis of retinal EC and umbilical cord vein EC in vitro at the same extent as basic fibroblast growth factor (bFGF). PC also stimulated angiogenesis by EC in mixed cultures. The angiogenic, proliferative and migration activities in CM from PC were inhibited by an antibody to bFGF. These data suggest that PC play an important role in angiogenesis through secretion of an FGF-like molecule.

Animals↗

PubMed1997

Cyclic tensile stretch on bovine articular chondrocytes inhibits protein kinase C activity.

Osteoarthrosis, a common pathway of joint deterioration, is caused by mechanical stress loaded on articular cartilage. We previously demonstrated the involvement of protein kinase C (PKC) in the development of osteoarthritis in vitro. In this study, we examined the effect of mechanical stress on chondrocyte metabolism and the activity of PKC in vitro. Low frequency and magnitude of cyclic tensile stretch loaded on chondrocytes increased proteoglycan synthesis. However, high frequency and magnitude of stress decreased its synthesis. In this condition, activity of PKC was reduced. These results suggest an involvement of PKC in the stress-mediated inhibition of proteoglycan synthesis.

Animals↗

PubMed1997

Urologic abnormalities in Menkes' kinky hair disease: report of three cases.

Menkes' kinky hair disease is a rare congenital disorder of copper metabolism with X-linked recessive inheritance. It is well known that it is frequently associated with urologic abnormalities. The authors experienced three such cases, but each of them was different. Multiple bladder diverticula, right vesico-ureteral reflux, and right hydronephrosis were noted on the first baby boy. In the second case, hematomas in the left kidney, pelvis, ureter and the adipose capsule, which were thought to be the abnormality of vessels, were noted in the neonatal period. In the third body, multiple bladder diverticular were noted at the age of 1 year. One year, 10 months later, a spontaneous rupture at the huge diverticulum occurred.

Abnormalities, Multiple↗

PubMed1997

A role for histamine receptors in rheumatoid arthritis.

Although neurotransmitters and various chemical mediators play an important role in the pathogenesis of rheumatoid arthritis (RA), precise underlying mechanisms have yet to be determined. Histamine is a classical mediator of inflammation and three types of receptors are known. We investigated the presence and functions of histamine receptors of lymphocytes, bone marrow cells, synovial fibroblasts, and chondrocytes in experimentally-induced arthritis and human RA. The function of H2 receptors in peripheral blood lymphocytes and bone marrow cells were down regulated as measured by increments of intracellular cAMP and IL-6 production. Synovial fibroblasts from RA patients did not respond to H2 agonist to synthesize hyaluronic acid. It is evident that H2 receptors are down-regulated in lymphocytes, bone marrow cells, and synovial fibroblasts. The reduced function of H2 receptors in collagen-induced arthritis was normalized by transfer of the receptor-bearing lymphocytes and bone marrow cells. These data suggest that histamine is involved in the pathogenesis of RA.

Animals↗

PubMed1997

Prevalence of GBV-C and hepatitis G virus variants in patients with fulminant hepatic failure in Japan.

BACKGROUND/AIMS: Whether GB virus C and hepatitis G virus participate in fulminant hepatic failure is controversial. We studied the prevalence of the viral RNA in 48 patients. There were possible routes of infection, including blood transfusion, in 22 patients (group 1), and no risk factors in the other 26 (group 2). METHODS: We assayed serum viral RNA with reverse transcription and nested polymerase chain reactions. Serum was obtained at admission, and after transfusion in group 2. RESULTS: Five (10%) serum samples from group 1 at admission had viral RNA of the 5'-untranslated region, and three of these samples had viral RNA of the NS3/helicase region. All five patients had transfusions before sampling. Two (4%) samples from group 2 were positive by both tests only after transfusion. Of two patients, one with non-A-E fulminant hepatic failure survived. Her serum alanine aminotransferase did not increase further after transfusion, but did stay above the reference range during follow-up. The other patient, with infection with hepatitis B virus detected at admission, died. After transfusion, his alanine aminotransferase did not increase further. Partial nucleotide sequences of GB virus C and hepatitis G virus from three fulminant hepatic failure patients and five control patients with chronic hepatitis C were compared with published sequences. A viral variant causing fulminant hepatitis, suggested elsewhere, was not found, nor was all of a characteristic pattern of six mutations found elsewhere. CONCLUSIONS: GB virus C and hepatitis G virus may cause hepatitis, but probably not severe hepatitis such as fulminant hepatic failure.

Base Sequence↗

PubMed1997

Demonstration of antibodies against human papillomavirus type-11 E6 and L2 proteins in patients with recurrent respiratory papillomatosis.

Recurrent respiratory papillomatosis (RRP) is highly prevalent in Thailand, with the human papillomavirus (HPV) type-11 being the most widespread. In this study, we isolated the HPV type-11 (HPV-11) genome from subjects with RRP and subcloned the E6 and L2 open reading frames (ORFs) with the expression vectors pEX1 and pEX3. The recombinant E6/beta-gal and L2/beta-gal fusion proteins were expressed in E. coli. Using the recombinant proteins, we demonstrated the presence of antibodies against HPV-11 E6 and L2 in RRP patients by Western blot analysis. The prevalence of seropositivity for HPV-11 E6 and L2 were 5% (1/20) and 10% (2/20), respectively. Although RRP is caused by infection on the mucosal surface, it appears that an immune response occurs against viral proteins expressed in the epithelial lesions.

Antibodies, Viral↗

PubMed1997

The expulsion of Echinostoma trivolvis: worm kinetics and intestinal reactions in C3H/HeN mice treated with dexamethasone.

C3H/HeN mice were each infected with 40 Echinostoma trivolvis metacercarial cysts on day 0, given intramuscular injections of dexamethasone (DEX) daily for 30 days, and necropsied on days 5, 8, 12, 15, 20 and 30 p. i. Control mice were each infected with 40 echinostome cysts on day 0, but were not treated with DEX and necropsied on the same days as the DEX-treated mice. DEX treatment caused an inhibition of worm expulsion and suppressed the increase in goblet cell numbers that peaked around day 12 p. i. in the untreated control mice. Increase in the number of mucosal mast cells and eosinophils in the control mice that peaked around day 15 and 12 p. i., respectively, was also suppressed by the DEX treatment. The mean body area of the worms from the DEX-treated mice was about the same as that of the control worms on day 5 p. i., and then significantly greater than the control worms on days 8 and 12 p. i. The worms in the treated mice continued to grow until the end of the experiment, on day 30 p. i. Enzyme-linked immunosorbent assay (ELISA) showed that serum IgM from the treated and control mice increased from day 12 p. i., peaked on day 15 p. i., and then decreased. An IgM titre of the treated mice was slightly higher than that of the controls. No marked rise in IgG and IgA titres occurred throughout the experiment in both groups.

Animals↗

PubMed1997

Inhibition of Ca2+ channel current by mu- and kappa-opioid receptors coexpressed in Xenopus oocytes: desensitization dependence on Ca2+ channel alpha 1 subunits.

1. Desensitization of mu- and kappa-opioid receptor-mediated inhibition of voltage-dependent Ca2+ channels was studied in a Xenopus oocyte translation system. 2. In the oocytes coexpressing kappa-opioid receptors with N- or Q-type Ca2+ channel alpha 1 and beta subunits, the kappa-agonist, U50488H, inhibited both neuronal Ca2+ channel current responses in a pertussis toxin-sensitive manner and the inhibition was reduced by prolonged agonist exposure. 3. More than 10 min was required to halve the inhibition of Q-type channels by the kappa-agonist. However, the half-life for the inhibition of N-type channels was only 6 +/- 1 min. In addition, in the oocytes coexpressing mu-opioid receptors with N-type or Q-type channels, the uncoupling rate of the mu-receptor-mediated inhibition of N-channels was also faster than that of Q-type channels. 4. In the oocytes coexpressing both mu- and kappa-receptors with N-type channels, stimulation of either receptor resulted in a cross-desensitization of the subsequent response to the other agonist. Treatment of oocytes with either H-8 (100 microM), staurosporine (400 nM), okadaic acid (200 nM), phorbol myristate acetate (5 nM) or forskolin (50 microM) plus phosphodiesterase inhibitor did not affect either the desensitization or the agonist-evoked inhibition of Ca2+ channels. 5. These results suggest that the rate of rapid desensitization is dependent on the alpha 1 subtype of the neuronal Ca2+ channel, and that a common phosphorylation-independent mechanism underlies the heterologous desensitization between opioid receptor subtypes.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗

PubMed1997

Modulation of apolipoprotein gene expression in fatty liver of obese rats: enhanced APOA-IV, but no APOB expression by a high sucrose diet.

OBJECTIVE: Hepatic lipoprotein production is important to the understanding of mechanisms involved in the development of fatty liver and hyperlipidemia. Previously, we have reported that hepatic fatty acid synthesis and apolipoproteinB transcription are increased in obese rats. Here, we describe the effects of a high sucrose diet on hepatic fatty acid synthesis and apolipoprotein gene expression in obese rats. DESIGN: Obese rats with ventromedial hypothalamic lesions were fed on a high sucrose diet (30.3% of cal) or lab chow for 11 weeks. RESULTS: Serum triglycerides and plasma immuno-reactive insulin concentrations were further increased in the obese rats fed a high sucrose diet. The experimental diet increased the activity of hepatic acetyl-CoA carboxylase, the rate limiting enzyme for hepatic fatty acid synthesis, and triglycerides content, concurrent with an increase abundance of apolipoproteinA-IC mRNA in the obese rats. Despite further accumulation of hepatic triglycerides there was no further increase in hepatic apolipoproteinB mRNA abundance in the obese rats fed the high sucrose diet. CONCLUSION: These data suggest that the synthesis of hepatic fatty acids but not of apolipoproteinB is further increased in obese rats fed the high sucrose diet, and that apolipoproteinA-IV gene expression may be modulated in response to alterations in hepatic triglycerides flux.

Acetyl-CoA Carboxylase↗

PubMed1997

Glucoregulatory disorders in school refusal students.

OBJECTIVES: Our previous studies demonstrated autonomic nervous system disorders and cerebral blood hypoperfusion in school refusal students with underlying emotional distress due to fear or anxiety associated with school attendance. Because severe stress is known to affect glucoregulatory metabolism, this study used the oral glucose tolerance test (OGTT) to measure glucose metabolism in school refusal students. DESIGN: A three-hour OGTT was performed. In preparation for the test, students fasted overnight. After a fasting blood sample was drawn, students were given solutions containing a predetermined amount of glucose based on their body weight (1.75 g/kg to a maximum 75 g). After glucose ingestion, blood samples were drawn at 30, 60, 90, 120, 150, and 180 mm to measure blood glucose (BG), immunoreactive insulin (IRI), pancreatic glucagon (IRG) and growth hormone (GH) levels. BG levels, IRI response, cumulative BG (sigma BG), cumulative IRI (sigma IRI), insulin/glucose ratio (delta IRI/delta BG), and insulinogenic index (sigma IRI/sigma BG) were then compared to previously reported normal control data. As an index of emotional difficulties, the self-rating depressive scale (SDS) was carried out. PATIENTS: Eighty-one school refusal students (40 males and 41 females), 11-19 years of age (14.8 +/- 2.1), were studied. Their school refusal periods ranged from one month to eight years. All students were within -15 to +20% (-0.04 +/- 8.6) of ideal body weight. MEASUREMENTS: BG levels were determined using a glucose oxidase reaction method. Serum hormones were measured by radioimmunoassay. RESULTS: BG levels at all OGTT time intervals and sigma BG were significantly higher in school refusal students than the normal control data (sigma BG: 39.5 +/- 4.4 vs 33.3 +/- 3.4 mmol/l P < 0.001). Although the insulin response was abnormally low relative to the prevailing hyperglycaemia (sigma IRI/ sigma BG: subjects vs control = 232 +/- 129 vs 375 +/- 271, P < 0.01), normal beta cell secretory ability was speculated (sigma IRI: subjects vs controls = 2805 +/- 1274 vs 2523 +/- 1219 pmol/l). This suggests a relative suppression of insulin secretion. A paradoxical increase of GH was observed in 19 students after glucose ingestion. CONCLUSIONS: Glucoregulatory disorders observed in school refusal students may be caused by emotional distress. Multiple factors including autonomic nervous system disorders, derangement of neuropeptides in the hypothalamus, and hormonal imbalances may also affect glucoregulatory metabolism, predisposing these students to hyperglycaemia. We speculate that the glucoregulatory system compensates for decreased blood flow to the brain by increasing blood glucose concentrations, thereby providing sufficient glucose as the primary energy source used during normal brain metabolism.

Adolescent↗

PubMed1997

Early specification of intestinal epithelium in the chicken embryo: a study on the localization and regulation of CdxA expression.

CdxA, a chicken homeobox-containing gene related to caudal in Drosophila, has been implicated in the regionalization of endoderm. It is reported here that, in the development of the chicken embryo, CdxA expression appears in the endoderm at day 1.5 of development as bilateral bands on either side of the splanchnopleure which later contribute to intestinal epithelium. The CdxA-expressing area extends medially and caudally as formation of the gut tube progresses. It is also shown that the rostral limit of CdxA expression demarcates the boundary between stomach and duodenum after day 3 of development. CdxA is not expressed in digestive tract appendages which open into the intestine, such as pancreas, liver and allantois. Early restriction of CdxA expression in intestinal lineage suggests that the intestinal specification involving CdxA expression commences before the gut tube is formed. The expression of CdxA in epithelial-mesenchymal tissue recombinants suggests that mesenchymal influence regulating CdxA expression plays an important role in confirming the boundary between the stomach and intestine. Chronological change in the spatial distribution of CdxA transcripts and the results of tissue recombination experiments, together with precise fate maps of early endoderm and splanchnic mesoderm, lead to a model of mechanisms by which intestinal specification is brought about.

Animals↗

PubMed1997

Reduction in formation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)-induced aberrant crypt foci in the rat colon by docosahexaenoic acid (DHA).

Docosahexaenoic acid (DHA), a major component of fish oil, suppresses the formation and growth of aberrant crypt foci induced by 1,2-dimethylhydrazine and azoxymethane. In the present study we examined the effects of intragastric gavage administration of DHA on the yield of rat colonic aberrant crypt foci due to treatment with a heterocyclic amine, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), which induces colon cancer in male F344 rats and is considered to be a possible human colon carcinogen. Male F344 rats were given a standard diet (AIN-76A) and received 10 doses of PhIP (75 mg/kg body wt, by intragastric intubation, on days 1-5 and 8-12) with or without intragastric application of 1 ml DHA 4 h prior to each carcinogen treatment, followed by further DHA dosing. The numbers of PhIP-induced aberrant crypt foci per colon after 4 and 12 weeks DHA administration were significantly reduced to 47 and 38% respectively of the values obtained when PhIP alone was used. The mean number of aberrant crypts per focus was also decreased by DHA treatment. At week 4 the PhIP-DNA adduct levels in the colon of rats from the PhIP+DHA group were approximately two thirds of the PhIP group value. The results thus suggest that DHA exerts a preventive effect on PhIP-induced colon carcinogenesis.

Animals↗

PubMed1997

Suppression of azoxymethane-induced rat colon carcinoma development by a fish oil component, docosahexaenoic acid (DHA).

The effects of intragastric gavage administration of docosahexaenoic acid (DNA) , a major component of fish oil, on azoxymethane (AOM)-induced colon carcinogenesis in rats was investigated. Male F344 rats were treated with 15 mg/kg body wt of AOM once a week, for two weeks. The animals were given either 1 ml of DHA or water intragastrically 5 times a week, starting the day before the first carcinogen treatment. The numbers of AOM-induced aberrant crypt foci in the rats given DHA were 76% and 62% of the control values, at 4 and 12 weeks, respectively. After 36 weeks of DHA treatment, colon tumors were counted and examined histologically. The blood plasma levels of prostaglandin E2 (PGE2) and polyunsaturated fatty acids were also quantified. The incidences of colon cancer did not differ, being 96% and 92% in the AOM and AOM+DHA groups, respectively. Colon cancer multiplicity was, however, significantly decreased by the DHA treatment; 3.65 +/- 2.18 in the AOM group and 2.41 +/- 1.58 in the AOM+DHA group (P <0.01). Notably, the numbers of moderately differentiated adenocarcinomas in the middle and distal colon in the DHA-treated group were lower than in the AOM group. The levels of PGE2 and arachidonic acid in the blood plasma of DHA-treated rats were also significantly lower than in the AOM group. These results suggest that DHA exerts its inhibitory effect on colon carcinogenesis by modulating lipid metabolism and inhibiting the arachidonic cascade.

Animals↗

PubMed1997

Does corpus luteum locally affect follicular growth negatively?

In this study bilateral ovarian follicular growth during the luteal phase was investigated in relation to the ovary where ovulation occurred. The diameter of the largest follicle in the contralateral ovary without corpus luteum and in the ipsilateral ovary with corpus luteum was measured using vaginosonography in a total of 66 natural cycles of 27 normally cycling women undergoing treatment with intrauterine insemination (IUI). None of the women received ovarian stimulation or luteal support. Follicles from 2 to 11 mm in diameter were measured in early luteal phase (day +1 to +4), mid-luteal phase (day +5 to +9) and late luteal phase (day +10 onwards). The mean diameters of the largest follicle in the contralateral ovary without corpus luteum during the early, mid- and late luteal phases were 6.81 +/- 1.33 (mean +/- SD), 6.14 +/- 1.29 and 5.71 +/- 1.17 mm respectively, while those of the ipsilateral ovary with corpus luteum were 6.48 +/- 1.40, 5.65 +/- 1.47 and 4.98 +/- 1.19 mm respectively. While there was no significant difference during the early luteal phase, the mean diameter of the largest follicle in the ipsilateral ovary with corpus luteum was significantly smaller than that of the contralateral ovary without corpus luteum during the mid-luteal phase (P < 0.004) and the late luteal phase (P < 0.0005). These results indicate that the corpus luteum locally affects neighbouring follicular growth negatively during the luteal phase of the menstrual cycle, with the most pronounced effect expressed in the mid- and late luteal phases.

Adult↗