Multi-vessel dissections in Marfan syndrome demonstrated by multislice computed tomography.
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Adult↗
Biomedical subjects
K Ito
Publications and source records attributed to K Ito.
Occipital hypoperfusion in Parkinson's disease without dementia: correlation to impaired cortical visual processing.
OBJECTIVE: The purpose of this study was to analyse changes in regional cerebral blood flow (rCBF) in Parkinson's disease (PD) without dementia. METHODS: Twenty eight non-demented patients with PD and 17 age matched normal subjects underwent single photon emission computed tomography with N-isopropyl-p-[(123)I]iodoamphetamine to measure rCBF. The statistical parametric mapping 96 programme was used for statistical analysis. RESULTS: The PD patients showed significantly reduced rCBF in the bilateral occipital and posterior parietal cortices (p<0.01, corrected for multiple comparison p<0.05), when compared with the control subjects. There was a strong positive correlation between the score of Raven's coloured progressive matrices (RCPM) and the rCBF in the right visual association area (p<0.01, corrected for multiple comparison p<0.05) among the PD patients. CONCLUSIONS: This study showed occipital and posterior parietal hypoperfusion in PD patients without dementia. Furthermore, it was demonstrated that occipital hypoperfusion is likely to underlie impairment of visual cognition according to the RCPM test, which is not related to motor impairment.
Aged↗
Deformation of chondrocytes in articular cartilage under compressive load: a morphological study.
The main function of articular cartilage is to transmit load. The objective of this study was to describe the deformation of chondrocytes under static loading and its relation to collagen matrix deformation. Whole intact rabbit knee joints were loaded statically with either high or low magnitude and long or short duration. Specimens were cryopreserved while under load and prepared for morphological evaluation by field emission scanning electron microscopy. With this method an immediate preservation of the chondrocyte in its loaded state was possible. Static compression of articular cartilage produced a zone-specific deformation of chondrocyte shape, depending on the magnitude and duration of load. Under high-force and long-duration loading, the chondrocytes showed considerable deformation concomitant with the highly deformed collagen fibres. Chondrocyte deformation occurred mostly in the transitional and upper radial zones and less in the lower layers. There was no significant change of the chondrocyte shape in the tangential zone under high- or low-force short-duration loading. These results show that the chondrocytes undergo significant changes in shape ex vivo and that they are sensitive to differences in the magnitude and duration of loads being applied. Chondrocyte deformation is strongly linked to the deformation of the surrounding cartilage collagen matrix.
Adaptation, Physiological↗
Association of culture of mouse urogenital complexes in media containing rodent sera with the appearance of primordial germ cell-like cells.
Primordial germ cells differentiate into germ cells and have the ability to reacquire totipotency. Mouse primordial germ cells are identified by alkaline phosphatase staining of the extraembryonic mesoderm, and they proliferate and migrate to reach the genital ridges. Mouse primordial germ cells have never been maintained in culture exclusively for longer than a week without differentiation or dedifferentiation. Moreover, primordial germ cells have not been proliferated with urogenital complexes in vitro, because gonad culture has never been successful. It was thought that primordial germ cells could proliferate in a culture of urogenital complex under modified medium conditions resembling those in vivo; however, organ culture of mouse gonad has been performed with fetal calf serum or equine serum, and those sera produce conditions different from those in vivo. Therefore, mouse urogenital complexes were cultured in media containing rodent sera. As a result, it was possible to proliferate primordial germ cell-like cells outside gonads, and these cells very closely resembled primordial germ cells. In addition, motile primordial germ cell-like cells could be obtained. The ability to maintain primordial germ cell-like cells in culture by this intra-species culture method is important in the study of gametogenesis. Furthermore, this method is useful as a source of stem cells such as embryonic germ cells.
Animals↗
Purification of mouse primordial germ cells by Nycodenz.
Primordial germ cells are important cells for the study of germ cell lineage. It has proved difficult to obtain highly purified primordial germ cells for preparation of a specific antibody. In the present study, a new method for purifying mouse primordial germ cells was developed using a Nycodenz gradient. Furthermore, the polyclonal anti-mouse primordial germ cells IgG derived from mouse primordial germ cells was prepared. As this IgG reacted only with primordial germ cells obtained at day 12.5 after mating, this antibody appeared to recognize the stage-specific antigen of primordial germ cells. One reason that a continuous primordial germ cell marker has not been obtained is because the purity of the primordial germ cells used has been too low to prepare the antibody. This new method represents a significant improvement in the purification of primordial germ cells; it is simpler than previous methods, and produced mouse primordial germ cells with a purity of more than 95%. In addition, the separation reagent Nycodenz is non-toxic and achieved separation of primordial germ cells without attachment of antibodies against the primordial germ cell membrane surface. This new purification method and stage-specific antibody will be useful for the analysis of the mechanisms of primordial germ cell migration.
Animals↗
A model to assess the risk of the introduction into Japan of the bovine spongiform encephalopathy agent through imported animals, meat and meat-and-bone meal.
The authors developed a mathematical model to assess the release risk of the bovine spongiform encephalopathy (BSE) agent into a country through the importation of live cattle, bone-in bovine meat and meat-and-bone meal (MBM) from the United Kingdom and other countries with BSE. Monte Carlo simulation was attempted using this model and input variables. The release risk in Japan, expressed as the weight of infected MBM released in Japan between 1993 and 2000, was estimated to be 23.4 kg to 53.8 kg. The simulation also indicated that imported MBM represented the most important risk factor for releasing the BSE agent into Japan. This paper also provides details of the first five cases of BSE detected in Japan between September 2001 and the end of 2002. In addition, the results of the investigation conducted to determine the source of infection and the measures taken by the Government of Japan to prevent the BSE agent from entering the food and feed chains are also outlined.
Animals↗
Novel aspects to the structure of rabbit articular cartilage.
Applying cryo and modified chemical preparation techniques, mainly for scanning electron microscopy, revealed entirely new aspects to the structure of the radial zone of rabbit tibial plateau articular cartilage. The aggrecan component of the extracellular matrix was contained radially in columns, each with a diameter of 1-3 mm, by a tightly packed matrix of collagen fibrils. The collagen fibrils were arranged radially, some straight and others in an opposed spiral arrangement, with regularly repeating patterns. This organization existed in the regions surrounding the columns of chondrocytes, known as chondrons. The load bearing property of the tissue was explained by the directed flow and containment of the interstitial fluid, modulated by the protein-carbohydrate complexes, along these collagen bounded tubular structures. The reason why such a structure has not been described previously may be that it is not retained by aldehyde fixation followed by dehydration, the method commonly used for tissue preparation for electron microscopy.
Journal Article↗
A variable number of tandem repeats in the serotonin transporter gene does not affect the antidepressant response to fluvoxamine.
A variable number of tandem repeats (VNTR) in the second intron of the serotonin transporter gene (STin2) has been studied in association with the susceptibility to affective disorders. Recently, it was reported that selective serotonin reuptake inhibitors were more effective in patients with major depressive disorder having the homozygous allele pair (12-copy/12-copy) of VNTR in the STin2 than in ones having other allele combinations. As the study had methodological problems, further studies are needed to confirm the above finding. Therefore, the authors investigated whether the allelic variation of VNTR in the STin2 was associated with the antidepressant response to fluvoxamine in 66 patients with major depressive disorder. Fluvoxamine was prescribed up to 200 mg/day in the dosing protocol for 6 weeks. The present study showed no significant association between the polymorphism of VNTR in the STin2 and the treatment response to fluvoxamine.
Adult↗
Effects of barley yellow mosaic disease resistant gene rym1 on the infection by strains of Barley yellow mosaic virus and Barley mild mosaic virus.
Although a Chinese landrace of barley, Mokusekko 3, is completely resistant to all strains of Barley yellow mosaic virus (BaYMV) and Barley mild mosaic virus (BaMMV), and is known to have at least two resistant genes, rym1 and rym5, only rym5 has been utilized for BaYMV resistant barley breeding in Japan. In order to clarify the effect of rym1 on BaYMV and BaMMV, and to utilize the gene for resistant barley breeding, the susceptibilities of only rym1 carrying breeding lines against BaYMV and BaMMV were investigated. In the assessment of resistance to BaYMV-I, 341 F(2) populations derived from a cross between the resistant line Y4 with only rym1 and the susceptible cv Haruna Nijo shows that the segregation loosely fits a 1R:3S ratio (0.05 > P > 0.01), suggesting that the resistance is controlled by a single recessive gene, rym1. Further, none of the F(3) lines derived from the nine resistant F(2) plants showed any disease symptoms in the field infected by BaYMV-I. The same nine F(3) lines showed almost the same agronomic characters in the field infected by BaYMV-III as those in the uninfected field, apart from the symptom of showing numerous mosaics. This result indicates that the gene rym1 has an acceptable level of resistance to BaYMV-III. In the assessment of resistance to BaYMV-II, BaMMV-Ka1 and -Na1, an artificial infection method was adopted and the susceptibilities to those viruses were investigated. Although the control varieties, Ko A and Haruna Nijo, were infected with all of them, the rym1 gene carrying BC(2)F(3) lines were completely resistant to all strains. In summary, rym1 is completely resistant to BaYMV-I, -II, BaMMV-Ka1 and -Na1, and has an acceptable level of resistance to BaYMV-III. This study concludes with a discussion of the reason why the important resistance gene rym1 was eliminated along with resistant cultivars during breeding for resistance to BaYMV.
Genes, Plant↗
Direct probe of the shape resonance mechanism in 2sigma(g)-shell photoionization of the N2 molecule.
Angular distributions of photoelectrons from a 2sigma(g) shell of fixed-in-space N2 molecules have been measured for left- and right-elliptically polarized and for linearly polarized light at several photon energies in the region of sigma(*) shape resonance. That allowed the determination of a set of dipole matrix elements and phase shift differences characterizing the process. These data clearly show the enhancement of the fsigma(u) partial cross section in the resonance simultaneously with an abrupt increase of the corresponding phase shift by pi, which is the first experimental demonstration of the nature of the sigma(*) shape resonance in homonuclear diatomic molecules.
Journal Article↗
Effect of MS-153 on the development of behavioral sensitization to locomotion- and ataxia-inducing effects of phencyclidine.
RATIONALE: Repeated administration of phencyclidine (PCP) produces behavioral sensitization to PCP. Although the precise mechanism is unknown, glutamatergic neurotransmission seems to play an important role in the development of sensitization. OBJECTIVES: The present study examined whether a novel compound, MS-153 (( R)-(-)-5-methyl-1-nicotinyl-2-pyrazoline), which has an ability to enhance glutamate uptake and inhibit glutamate release, would block the development of behavioral sensitization to PCP. METHODS: For studying effects of MS-153, locomotor activity was measured by an infrared sensor and ataxia was measured by a rating scale. RESULTS: MS-153 (10 and 100 mg/kg) enhanced locomotion and ataxia induced by a single injection of PCP (7.5 mg/kg). Repeated administration of PCP (20 mg/kg, once in every day, for 5 days) developed sensitization to locomotion- and ataxia-inducing effects of PCP (7.5 mg/kg). MS-153 given 60 min and 120 min later of every PCP treatment blocked the development of behavioral sensitization to both locomotion- and ataxia-inducing effects of PCP. Co-administration of MS-153 with repeated saline treatment did not produce hypersensitivity to PCP. CONCLUSIONS: These results suggest that the attenuation of glutamatergic neural transmission enhances acute effects of PCP, in contrast, blocks the behavioral sensitization developed by repeated PCP treatment. Therefore, glutamatergic neural transmission plays an important role in the development of behavioral sensitization to PCP.
Animals↗
Expression and sequence analyses of p33(ING1) gene in myeloid leukemia.
p33(ING1) is a novel candidate tumor suppressor gene which is involved in the regulation of apoptosis. p33(ING1) interacts with p53 signaling pathway and regulates cellular growth. It has reported that the expression of p33(ING1) mRNA was decreased in lymphoid malignancies. We thus investigated the potential involvement of p33(ING1) abnormalities in myeloid leukemias. However, the levels of p33(ING1) transcript were almost equal in 3 AML cell lines and 10 fresh AML samples. In addition, neither point mutations nor deletions in p33(ING1) gene were found in myeloid leukemias. These results suggest that p33(ING1) may not be a major candidate tumor suppressor gene in myeloid leukemias.
Adenocarcinoma↗
Discrimination between Alzheimer dementia and controls by automated analysis of multicenter FDG PET.
A new diagnostic indicator of FDG PET scan abnormality, based on age-adjusted t statistics and an automated voxel-based procedure, is presented and validated in a large data set comprising 110 normal controls and 395 patients with probable Alzheimer's disease (AD) that were studied in eight participating centers. The effect of differences in spatial resolution of PET scanners was minimized effectively by filtering and masking. In controls FDG uptake declined significantly with age in anterior cingulate and frontolateral perisylvian cortex. In patients with probable AD decline of FDG uptake in posterior cingulate, temporoparietal, and prefrontal association cortex was related to dementia severity. These effects were clearly distinct from age effects in controls, suggesting that the disease process of AD is not related to normal aging. Women with probable AD had significantly more frontal metabolic impairment than men. The new indicator of metabolic abnormality in AD-related regions provided 93% sensitivity and specificity for distinction of mild to moderate probable AD from normals, and 84% sensitivity at 93% specificity for detection of very mild probable AD (defined by Mini Mental Score 24 or better). All regions related to AD severity were already affected in very mild AD, suggesting that all vulnerable areas are affected to a similar degree already at disease onset. Ventromedial frontal cortex was also abnormal. In conclusion, automated analysis of multicenter FDG PET is feasible, provides insights into AD pathophysiology, and can be used potentially as a sensitive biomarker for early AD diagnosis.
Aged↗
A comparison of the progression of early Parkinson's disease in patients started on ropinirole or L-dopa: an 18F-dopa PET study.
OBJECTIVE: To study the relative rates of progression of early Parkinson's disease (PD) in patients started on a dopamine agonist, ropinirole, or L-dopa. METHODS: A double-blind study of 45 early PD patients [mean age 61 +/- 9.8 SD and mean symptom duration, 26 +/- 16 SD months] randomized 2 : 1 (ropinirole : L-dopa). Supplementary L-dopa was allowed if, during the trial, there was lack of a therapeutic effect. (18)F-dopa PET scans were performed at baseline (n = 45) and 2 years (n = 37). RESULTS: At two years, the mean percentage reduction in putamen (18)F-dopa uptake (Ki(o)) was not significantly different between the two groups (13% ropinirole, n = 28 versus 18% L-dopa, n = 9). CONCLUSIONS: We found no significant overall difference in underlying PD progression, after two years treatment, between patients groups. In summary, (18)F-dopa PET can be employed to objectively evaluate the effect of potential neuroprotective agents on dopaminergic function.
Aged↗
Optimal use of tacrolimus in living donor renal transplantation in children.
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Adolescent↗
Intracellular recordings of pontine medial gigantocellular tegmental field neurons in the naturally sleeping cat: behavioral state-related activity and soma size difference in order of recruitment.
Intracellular recordings and neurobiotin labeling of medial pontine gigantocellular tegmental field (m-PFTG) neurons in the undrugged, naturally sleeping cat were performed to establish the relationship between soma size and membrane potential (MP) activity before and during the onset of the rapid eye movement (REM) phase of sleep. Initial recordings without labeling revealed that recorded neurons in the m-PFTG had a tonic, sustained membrane depolarization in REM sleep as compared with more polarized MP levels in slow-wave sleep (S) and phasic depolarizations in wakefulness (W) on a more polarized MP level. In neurobiotin-labeled neurons, there was a strong correlation between the soma size of m-PFTG neurons and the 'lead time', the time of onset relative to the beginning of REM, of a sustained increase in membrane depolarization. Thirty-nine m-PFTG neurons with soma cross-sectional areas ranging from 2098 microm(2) to 5958 microm(2) (mean value 3833.8 microm(2)) were analyzed. A majority of these m-PFTG neurons showed an increase in membrane depolarization associated with depolarizing postsynaptic potentials (PSPs) and spike generation that occurred before electrographic signs of REM sleep onset, while the rest of the neurons depolarized at the beginning of or just after REM sleep onset. Our previous work had suggested that many of these m-PFTG neurons were output neurons to the spinal cord. Analysis of the onset time of sustained membrane depolarization (Leadtime(MP)) revealed that larger cells had a longer lead time, while analysis of the lead times for onset of sustained PSPs and action potentials (Leadtime(AP)) showed this measure not to be dependent on soma size, but to be rather uniform, occurring just before the onset of REM sleep. Hence recruitment time, defined as the difference between Leadtime(AP) and Leadtime(MP), was dependent on cell soma size, implying that larger neurons may take longer to depolarize to an MP level critical for generating sustained action potentials, while smaller neurons may require less time.
Action Potentials↗
A case of drug-induced colitis complicating the administration of hydroxycarbamide.
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Antineoplastic Agents↗