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Biomedical subjects

Masaki Takahashi

Publications and source records attributed to Masaki Takahashi.

At least 19 recordsLinked to original sources

Campylobacter coli enteritis and Guillain-Barré syndrome: no evidence of molecular mimicry and serological relationship.

Campylobacter coli was isolated from two Guillain-Barré syndrome (GBS) patients who had anti-GM1 and anti-GD1 IgG antibodies. Although both this bacteria and Campylobacter jejuni are common causes of diarrheal illness, previous studies have focused only on C. jejuni as the causal agent of GBS. To determine whether C. coli also is a causative agent, we examined the hypothesis that production of anti-ganglioside antibodies is induced by ganglioside-mimics on that bacterial lipo-oligosaccharide (LOS), as in C. jejuni-associated GBS. LOSs of both C. coli isolates had very weak reactivities with anti-GM1 and anti-GD1a IgG monoclonal antibodies, whereas those of some GBS-related C. jejuni isolates had strong reactivities. Anti-GM1 and anti-GD1a IgG antibodies from the two patients were not absorbed as much by the LOSs of their isolates as were those of GBS-related C. jejuni strains. These findings do not support the hypothesis of ganglioside mimicry on C. coli isolates' LOSs. We next made a serological assay of recent C. coli infection in 74 patients with GBS, 26 with Fisher syndrome (FS), 49 with other neurological diseases (OND), and 37 normal controls (NC) using the bacterial outer membrane protein as antigen. Eight (11%) GBS and two (8%) FS patients had two or three classes of IgG, IgM, and IgA anti-C. coli antibodies. Anti-C. jejuni IgG and IgA antibody titers were significantly higher than those of anti-C. coli (respectively, p = 0.03 and 0.01). This suggests that anti-C. coli antibodies cross-react with C. jejuni protein. We concluded that a C. coli infection was not the cause of GBS in our patients. Both isolation of a microorganism from, and the positive infectious serology of, GBS patients do not always indicate the causal agent.

Adult↗

Comprehensive analysis of bacterial risk factors for the development of Guillain-Barre syndrome after Campylobacter jejuni enteritis.

BACKGROUND: Guillain-Barre syndrome (GBS), a postinfectious autoimmune-mediated neuropathy, is a serious complication after Campylobacter jejuni enteritis. METHODS: To investigate the bacterial risk factors for developing GBS, genotypes, serotypes, and ganglioside mimics on lipo-oligosaccharide (LOS) were analyzed in C. jejuni strains from Japanese patients. RESULTS: Strains from patients with GBS had LOS biosynthesis locus class A more frequently (72/106; 68%) than did strains from patients with enteritis (17/103; 17%). Class A strains predominantly were serotype HS:19 and had the cstII (Thr51) genotype; the latter is responsible for biosynthesis of GM1-like and GD1a-like LOSs. Both anti-GM1 and anti-GD1a monoclonal antibodies regularly bound to class A LOSs, whereas no or either antibody bound to other LOS locus classes. Mass-spectrometric analysis showed that a class A strain carried GD1a-like LOS as well as GM1-like LOS. Logistic regression analysis showed that serotype HS:19 and the class A locus were predictive of the development of GBS. CONCLUSIONS: The high frequency of the class A locus in GBS-associated strains, which was recently reported in Europe, provides the first GBS-related C. jejuni characteristic that is common to strains from Asia and Europe. The class A locus and serotype HS:19 seem to be linked to cstII polymorphism, resulting in promotion of both GM1-like and GD1a-like structure synthesis on LOS and, consequently, an increase in the risk of producing antiganglioside autoantibodies and developing GBS.

Antibodies, Bacterial↗

Amyloid beta up-regulates brain-derived neurotrophic factor production from astrocytes: rescue from amyloid beta-related neuritic degeneration.

Astrocytes, the most abundant type of glia in the brain, are considered to play a key role in Alzheimer's disease (AD) pathologies. In a cell culture study, we have previously shown that astroglial responses against amyloid beta (Abeta) occur before obvious neuronal damage could be detected, suggesting the possibility that astrocytes might be an attractive therapeutic target for treating AD. In the present study, we investigated astroglial gene expression changes in response to Abeta to elucidate further the role of astrocytes in Abeta toxicity. By using real-time PCR and ELISA analyses, we found that Abeta rapidly induced astrocytes to produce brain-derived neurotrophic factor (BDNF). Abeta42 was more effective than Abeta40 in increasing astroglial BDNF production. Moreover, BDNF treatment rescued the neuronally differentiated human neuroblastoma cells from neuritic degeneration caused by Abeta toxicity. This is the first study to demonstrate that astrocytes are capable of increasing the production of a particular neurotrophic factor in response to Abeta. Our findings also identify BDNF as a potential therapeutic agent for preventing Abeta-related neuritic degeneration.

Amyloid↗

Cardiorenal protective effects of year-long antihypertensive therapy with an angiotensin-converting enzyme inhibitor or a calcium channel blocker in spontaneously hypertensive rats.

BACKGROUND: The objective of this study was to evaluate the effect of year-long antihypertensive therapy with a calcium channel blocker and an angiotensin-converting enzyme (ACE) inhibitor on cardiac and renal injury. METHODS: Male 15-week-old spontaneously hypertensive rats (SHR) were given either a normal diet and normal drinking water (n = 10), a diet containing 0.05% nitrendipine (n = 10), or drinking water containing 50 mg/L of quinapril (n = 10). After 12 months of antihypertensive treatment, cardiovascular organ injuries were evaluated. RESULTS: Tail-cuff blood pressure (BP) at 12 months was significantly lower in animals receiving nitrendipine or quinapril than in control animals (control, 231 +/- 2 mm Hg; nitrendipine, 194 +/- 3 mm Hg; quinapril, 191 +/- 3 mm Hg; P < .001). Furthermore, aortic thickness was reduced by nitrendipine (-19%, P < .001) or quinapril (-21%, P < .001), and cardiac ventricular weight was significantly reduced by quinapril (-18%, P < .001) but not by nitrendipine (-5%, P = not significant [NS]). Echocardiography at 12 months revealed that midwall fractional shortening was higher in the quinapril group than in the control or the nitrendipine groups (control, 9.3% +/- 0.5%; nitrendipine, 9.8% +/- 0.5%; quinapril, 10.6% +/- 0.6%; P < .05). Left ventricular hydroxyproline levels were lower in the nitrendipine group (-21%, P < .01) and the quinapril group (-36%, P < .001) than in the control animals. In control SHR, creatinine clearance began to decrease and proteinuria began to increase at 6 to 9 months. Quinapril but not nitrendipine attenuated these markers of renal impairment (creatinine clearance at 12 months: control, 4.7 +/- 0.4 mL/min/kg; nitrendipine, 5.0 +/- 0.4 mL/min/kg; quinapril, 6.1 +/- 0.4 mL/min/kg; P < .05). Histologically, the glomerular injury score was lower in the quinapril group than in the control or nitrendipine groups (control, 19 [range, 8 to 30]; nitrendipine, 18 [range, 9 to 32]; quinapril, 7 [range, 3 to 12]; P < .01). CONCLUSIONS: It is suggested that year-long antihypertensive therapy with an angiotensin-converting enzyme (ACE) inhibitor is superior to a calcium channel blocker in terms of cardiorenal protection in SHR.

Angiotensin-Converting Enzyme Inhibitors↗

Effects of imidapril on left ventricular mass in chronic hemodialysis patients.

Left ventricular hypertrophy is considered to be a major cardiovascular risk factor in hemodialysis patients. Not only high blood pressure but also humoral factors such as angiotensin II and aldosterone are thought to contribute to the increase in left ventricular mass. We examined the effects of an angiotensin converting enzyme (ACE) inhibitor, imidapril, on left ventricular mass in patients with end-stage renal diseases on maintenance hemodialysis. Thirty patients on chronic hemodialysis were randomly divided into 2 groups of 15 patients each and given placebo or 2.5 mg imidapril once daily for 6 months. Before and after the 6-month period, left ventricular mass was evaluated by echocardiography, and circulating factors of the renin-angiotensin-aldosterone system were measured. Background characteristics such as age, gender ratio, causes of renal failure, duration of hemodialysis, body mass index and pre-dialysis blood pressure were comparable between the placebo and the imidapril groups. Systolic and diastolic blood pressures were not significantly changed in either group during the study period. In the imidapril group, serum ACE was reduced (12 +/- 1 to 5 +/- 2 U/l, p < 0.01) and plasma renin activity was increased (3.3 +/- 0.8 to 8.1 +/- 3.2 ng/ml/h, p < 0.01), but plasma angiotensin II and aldosterone were not significantly changed after 6 months (13 +/- 3 to 17 +/- 3 pg/ml and 365 +/- 125 to 312 +/- 132 pg/ml, respectively). On the other hand, left ventricular mass index was significantly decreased in the imidapril group (132 +/- 10 to 109 +/- 6 g/m2, p < 0.05) but was unchanged in the placebo group (129 +/- 6 to 126 +/- 5 g/m2). These results suggest that an ACE inhibitor reduces left ventricular mass in hemodialysis patients by a mechanism that is independent of changes in blood pressure.

Angiotensin-Converting Enzyme Inhibitors↗

Monitoring synaptogenesis in the developing mouse cerebellum with an original oligonucleotide microarray.

Use of DNA microarrays in neuroscience have been limited to rough screening purposes, mainly because the reliability and sensitivity of available arrays are not high enough. Because only a few hundred to one thousand genes are usually found to change expression levels in most experiments, we attempted to develop a more quantitative array by the following strategies: 1) limit the genes to those relevant to the experimental system, 2) design oligonucleotide probes of specified molecular properties so that more stringent hybridization conditions can be employed, 3) place six spots per probe on one slide and use multiple normalization genes, and 4) use a new type of gold-coated slide with higher S/N ratio. Genes involved in the construction and functioning of the synapse were selected from the literature as well as experimentally by comparing cerebella from hypothyroid and control mice at postnatal day 15 (P15). Although the number of genes covered was not yet large (172 genes), the custom array "Synaptoarray" thus constructed was capable of detecting +/-20% difference in gene expression ratios. Analysis of the postnatal development of the mouse cerebellum by using Synaptoarray demonstrated a general expression pattern with a peak at P7, followed by a decline at P15 and a partial recovery after P21. P10 clearly marked the end of the initial growth stage and a major transcriptional turning point in this system. This result suggests that such a custom array should be useful in monitoring perturbations to the normal developmental program.

Animals↗

Atlantoaxial transarticular screw fixation and posterior fusion using ultra-high-molecular-weight polyethylene cable.

This article attempts to evaluate the effectiveness of the ultra-high-molecular-weight polyethylene (UHMW-PE) cable system in atlantoaxial transarticular screw fixation and posterior fusion through the clinical results of 10 postoperative patients with atlantoaxial subluxation secondary to rheumatoid arthritis. Among them, one patient with only one screw placed owing to an anomalous vertebral artery had the correction loss of the 3-mm atlas-dens interval after surgery. Another patient had a second operation to remove the screw and cable after 2 years 11 months because a unilateral transarticular screw had come to protrude through the lateral mass of the atlas ventrally. All patients had achieved C1-C2 osseous fusion without any complications associated with this cable system. The UHMW-PE cable is a very useful material as sublaminar wiring in atlantoaxial transarticular screw fixation and posterior fusion.

Aged↗

Epidemiology of Campylobacter jejuni isolated from patients with Guillain-Barré and Fisher syndromes in Japan.

Campylobacter jejuni isolation is the standard for the diagnosis of this type of bacterial infection, but there have been no epidemiological studies of a large number of C. jejuni isolates from patients with Guillain-Barre syndrome (GBS) and Fisher syndrome (FS). For 13 years, stool specimens from GBS/FS patients have been sent from 378 hospitals throughout Japan to the Tokyo Metropolitan Institute of Public Health. A total of 113 strains (11%) were isolated from the stool specimens from 1,049 patients. The isolation rate did not differ by region. The rates were 22% for 449 patients with a history of diarrhea and 2% for the others. An additional 18 isolates were provided by various hospitals. There was no noticeable seasonal distribution in the onset of C. jejuni isolated from patients with GBS/FS. The male/female ratios were 1.7:1 for GBS and 2.2:1 for FS. The patient age range showed a peak in 10- to 30-year-old subjects who had GBS and in 10- to 20-year-old subjects who had FS. The predominance of young adults and male patients who had C. jejuni-associated GBS/FS may be related to the preponderance of young adults and male patients who had C. jejuni enteritis. The median interval from diarrhea onset to neurologic symptom onset was 10 days for GBS/FS. Penner's C. jejuni serotype HS:19 was more frequently present in GBS (67%) than in enteritis (6%) patients. HS:2 was more frequent in FS (41%) than in enteritis (14%) patients. These findings suggest that certain C. jejuni strains specifically trigger GBS and that others specifically trigger FS.

Adolescent↗

Protective effects of an angiotensin II receptor blocker and a long-acting calcium channel blocker against cardiovascular organ injuries in hypertensive patients.

The purpose of this study is to compare the long-term effects of an angiotensin II receptor blocker (ARB) and a long-acting calcium channel blocker (CCB) on left ventricular geometry, hypertensive renal injury and a circulating marker of collagen synthesis in hypertensive patients. Patients with essential hypertension (24 men and 19 women; age, 37-79 years) were treated with a long-acting CCB, amlodipine (AML; 2.5-7.5 mg once daily) for 6 months. Then, AML was switched to an ARB, candesartan (CS; 4-12 mg once daily), in 22 patients (CS group), while AML was continued in the remaining 21 patients for another 6 months (AML group). At the end of each treatment period, ambulatory blood pressure monitoring (ABPM), echocardiography and sampling of blood and urine were performed. The average office blood pressure during the latter period was comparably controlled in the AML and the CS groups (AML: 130 +/- 8/87 +/- 7 mmHg; CS: 133 +/- 11/ 88 +/- 7 mmHg), while the average systolic blood pressure of 24-h ABPM was significantly lower in the AML than in the CS group (127 +/- 9 vs. 133 +/- 14 mmHg, p<0.05). Consequently, the left ventricular mass index was significantly decreased in the AML group (102 +/- 18 to 92 +/- 12 g/m2, p<0.05), while the change was insignificant in the CS group (103 +/- 25 to 98 +/- 21 g/m2). On the other hand, plasma procollagen I C-terminal peptide (PICP), a marker of collagen synthesis, was lowered by CS (86 +/- 21 to 70 +/- 21 ng/ml, p<0.01), but was not significantly affected by AML (80 +/- 127 to 74 +/- 91 ng/ml). CS reduced urinary albumin excretion (57 +/- 123 to 26 +/- 33 mg/g creatinine, p<0.05), but AML did not bring about significant changes (85 +/- 27 to 73 +/- 19 mg/g creatinine). The results suggested that long-acting CCBs are effective in improving left ventricular hypertrophy by controlling 24-h blood pressure, while ARBs possess protective effects against cardiovascular fibrosis and renal injury beyond their antihypertensive effects.

Adult↗

Cloning and expression of canine interferon-alpha genes in Escherichia coli.

We cloned five new subtypes of cDNA encoding canine interferon-alpha (CaIFN-alpha) from a canine epithelial cell line. CaIFN-alphas were divided into two groups by amino acid sequences and a molecular phylogenic tree. Two subtypes of them were expressed in Escherichia coli, and IFN proteins were purified. Recombinant CaIFN-alphas were highly species-specific and showed antiviral activity against Vesicular stomatitis New Jersey virus and canine adenovirus-1 , but not against canine herpesvirus-1.

Adenoviruses, Canine↗

Total synthesis of (-)-incarvilline, (+)-incarvine C, and (-)-incarvillateine.

The first total syntheses of new monoterpene alkaloids (-)-incarvilline, (+)-incarvine C, and (-)-incarvillateine, corresponding to the natural enantiomers, have been accomplished. The strategy for the synthesis of these natural products utilized 6-epi-incarvilline as a common precursor, which was assembled by a three-component coupling reaction using (4S)-4-siloxy-2-cyclopenten-1-one to construct an appropriately trisubstituted cyclopentanone, followed by ring closure to the cis-perhydro-2-pyrindine skeleton by means of a reductive Heck-type reaction. Furthermore, topochemically controlled [2 + 2] photodimerization of cinnamic acid derivatives in the solid state for the stereospecific construction of a 1,2,3,4-tetrasubstituted cyclobutane ring was also investigated as a means to access (-)-incarvillateine.

Alkaloids↗

[Investigation of pesticide residues in foods distributed in Kitakyushu City].

We investigated 160 kinds of pesticide residues in 715 samples of 116 kinds of foods distributed in Kitakyushu city. Sixty kinds of pesticides were detected in 55 kinds of foods (204 samples) in the range of 0.002-22 mg/kg. Five kinds of pesticides in 7 samples violated the residue standards and the indication of "unused". The detection ratios of unregulated pesticide in domestic and imported foods were 27.8 and 33.0%, respectively. Iprodione, dicofol, diethofencarb, procymidone and chlorfenapyr (for domestic food) and total bromine, benomyl, chlorpyrifos, dicofol, fenvalerate, cypermethrin and dimethoate (for imported food) showed relatively high detection ratios. Chinese cabbage, garland chrysanthemum, tomatoes and green teas (domestic) and broccoli, bananas, grapefruit, lemons, oranges, frozen edamame and frozen kidney beans (imported) showed high relative pesticide detection ratios. Residual pesticides were detected with relatively high frequency in imported fruits, imported frozen foods and imported processed foods.

Chromatography, Gel↗

[Effect of hemodialysis on peak velocity of early diastolic mitral annulus motion].

OBJECTIVES: Peak velocities of early diastolic mitral annulus motion (Ea) assessed by tissue Doppler imaging are relatively preload independent. Whether Ea decreases after hemodialysis or not is unclear. This study investigated the effect of hemodialysis on Ea. METHODS: The study group consisted of 23 hemodialysis patients without organic heart disease. Echocardiography was performed before and after hemodialysis, and Ea was compared with the peak velocity of early mitral inflow (E). Decreases in the body weight, E and Ea were calculated as indexes of decrease by hemodialysis. RESULTS: After hemodialysis, E decreased significantly (p = 0.005) but Ea did not change (p = 0.09). The decrease in Ea was significantly smaller than that in E (p < 0.0001). The decrease in E correlated significantly (r = 0.52, p < 0.05) with the decrease in the body weight, but the decrease in Ea did not correlate with the decrease in the body weight. CONCLUSIONS: Ea is little affected by hemodialysis compared with E. The effect of hemodialysis on Ea can be ignored if the amount of fluid removal is small.

Aged↗

Ependymal cell reactions in spinal cord segments after compression injury in adult rat.

Recently, it has been suggested that neural stem cells and neural progenitor cells exist in the ependyma that forms the central canal of the spinal cord. In this study, we produced various degrees of thoracic cord injury in adult rats using an NYU-weight-drop device, assessed the degree of recovery of lower limb motor function based on a locomotor rating scale, and analyzed the kinetics of ependymal cell proliferation and differentiation by proliferating cell nuclear antigen (PCNA), nestin, glial fibrillary acidic protein (GFAP), or GAP-43 immunostaining. The results showed that the time course of the ependymal cell proliferation and differentiation reactions differed according to the severity of injury, and that the responses occurred not only in the neighborhood of the injury but in the entire spinal cord. An increase in the locomotor rating score was related to an increase in the number of PCNA-positive cells, and the differentiation of ependymal cells into reactive astrocytes was involved in injury repair. No apoptotic cells in the ependyma were detectable by the TUNEL method. These results indicate that the ependymal cells of the spinal central canal are themselves multipotent, can divide and proliferate according to the severity of injury, and differentiate into reactive astrocytes within the ependyma without undergoing apoptosis or cell death.

Animals↗

Anterior fusion and posterior correction of severe cervical kyphosis using pedicle screw fixation in a patient with neurofibromatosis: a case report.

We present a 15-year-old boy with severe cervical kyphosis due to neurofibromatosis (NF), who underwent one-stage anterior fusion and posterior correction using pedicle screw fixation. The kyphosis was corrected from 72 degrees to 35 degrees. At the follow-up 16 months postoperatively, anterior fusion and posterior stabilization had been obtained without correction loss. Cervical pedicle screw fixation is a useful method for the correction of severe cervical kyphosis in patients with NF.

Adolescent↗

Multiple left ventricular diverticula detected by second harmonic imaging: a case report.

A 51-year-old Japanese man was admitted to hospital for evaluation of anterior chest pain at rest. He had a past history of cerebellar infarction when he was 47 years old. A conventional 2-dimensional echocardiogram revealed normal left ventricular function, and no abnormal findings. However, second harmonic imaging demonstrated 2 noncontractile diverticula at the submitral annular portion of the posterior wall of the left ventricle. Second harmonic imaging revealed another contractile diverticulum at the anterior wall of left ventricle in the short-axis view. These findings were confirmed by left ventriculography. After confirming the diagnosis of multiple left ventricular diverticula, a rare type of congenital anomaly, anticoagulant therapy was started and he is well to date. Left ventricular diverticula are clinically very important because they are often associated with serious complications such as systemic thromboembolism. Enhancement of the left ventricular endocardial borders by second harmonic imaging is useful for the diagnosis of left ventricular diverticula.

Anticoagulants↗

[Myocardial systolic function of the left ventricle along the long axis in patients with essential hypertension: a study by pulsed tissue Doppler imaging].

OBJECTIVES: Myocardial contractility of the left ventricle along the long axis in hypertensives is not well characterized. The systolic velocities of the left ventricular myocardium along the long axis were measured by pulsed tissue Doppler imaging in patients with mild to moderate essential hypertension. The relationships between the systolic velocity of left ventricular myocardium along the long axis and the blood pressure, and the left ventricular geometry were investigated. METHODS: The study included 60 untreated hypertensive patients (hypertension group) and 59 age-matched healthy subjects (control group). M-mode echocardiograms were recorded, and the relative wall thickness, left ventricular mass index and left ventricular end-systolic stress were calculated. The peak systolic velocities of the left ventricular posterior wall motion (Sw) were measured by pulsed tissue Doppler imaging. RESULTS: The Sw was significantly lower in the hypertension group than in the control group (8.3 +/- 1.9 vs 9.2 +/- 2.0 cm/sec, p < 0.05). The Sw was correlated inversely with systolic blood pressure (r = -0.31, p < 0.005), diastolic blood pressure (r = -0.25, p < 0.0001), interventricular septal thickness (r = -0.41, p < 0.0001), left ventricular posterior wall thickness (r = -0.39, p < 0.0001), relative wall thickness (r = -0.33, p < 0.001), and left ventricular mass index (r = -0.37, p < 0.001) in all subjects. CONCLUSIONS: The systolic velocity of the left ventricular myocardium along the long axis is decreased in patients with mild to moderate essential hypertension, and is negatively correlated with blood pressure and the severity of left ventricular concentric hypertrophy.

Adult↗