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Biomedical subjects

H Matsuda

Publications and source records attributed to H Matsuda.

At least 19 recordsLinked to original sources
PubMed2007

Changes in regional cerebral blood flow during acute electroconvulsive therapy in patients with depression: positron emission tomographic study.

BACKGROUND: Although electroconvulsive therapy (ECT) is widely used to treat psychiatric disorders such as depression, its precise neural mechanisms remain unknown. AIMS: To investigate the time course of changes in cerebral blood flow during acute ECT. METHOD: Cerebral blood flow was quantified serially prior to, during and after acute ECT in six patients with depression under anaesthesia using [(15)O]H(2)O positron emission tomography (PET). RESULTS: Cerebral blood flow during ECT increased particularly in the basal ganglia, brain-stem, diencephalon, amygdala, vermis and the frontal, temporal and parietal cortices compared with that before ECT. The flow increased in the thalamus and decreased in the anterior cingulate and medial frontal cortex soon after ECT compared with that before ECT. CONCLUSIONS: These results suggest a relationship between the centrencephalic system and seizure generalisation. Further, they suggest that some neural mechanisms of action of ECT are mediated via brain regions including the anterior cingulate and medial frontal cortex and thalamus.

Adult↗
PubMed2006

Control of Schistosoma mekongi in Cambodia: results of eight years of control activities in the two endemic provinces.

In Cambodia, schistosomiasis is transmitted in the provinces of Kratie and Stung Treng where approximately 80000 individuals are estimated to be at risk of infection. The baseline prevalence of infection was estimated to be between 73% and 88%, and cases of severe morbidity (hepatosplenomegaly, puberty retardation) and mortality were very common. In 1994, the Ministry of Health of Cambodia started schistosomiasis control applying universal chemotherapy with praziquantel (40mg/kg). The coverage of the programme was between 62% and 86% for 8 years. This simple control measure resulted in the control of the disease: no cases were reported in 2004 and only three cases were reported in 2005. In addition, there are no longer reports of cases of severe morbidity due to schistosomiasis. Since the beginning of the control programme, a single dose of mebendazole (500mg) has been combined with praziquantel during the mass chemotherapy; as a result the prevalence of Ascaris lumbricoides and hookworms dropped from 74.5% to 10% and from 86% to 40% respectively. The experience in Cambodia demonstrates that, with political commitment, control of parasitic diseases is achievable even in a situation of minimal resources. The programme represents a successful model for other developing countries.

Adolescent↗
PubMed2006

Inclusion of the transcervical approach in video-assisted thoracoscopic extended thymectomy (VATET) for myasthenia gravis: a prospective trial.

BACKGROUND: Because evidence-based data regarding the quality of video-assisted thoracoscopic thymectomy for the treatment of myasthenia gravis are lacking, a prospective trial comparing three different operative approaches was conducted to evaluate their efficacy. METHODS: This prospective study enrolled 20 consecutive patients with nonthymomatous myasthenia gravis. A series of three approaches for bilateral video-assisted thoracoscopic extended thymectomy (VATET) using the anterior chest wall-lifting method (original), the original method with a flexed-neck position (modified), and the original method with a transcervical approach (final) were prospectively performed in each patient for quantitative and pathologic evaluation of the residual thymus after each approach. RESULTS: Complete VATET required 242 +/- 48 min, with the transcervical procedure requiring 23 +/- 12 min. After the modified method, the residual thymus in the cervical region was 1.5 cm in size and weighed 0.8 g (0.8% of the entire thymus), as compared with a size of 2.2 cm and a weight of 1.3 g (3.2%) after the original method. Each value is the result of comparison with the final method. Histopathologic studies showed residual tissue in the germinal center as well as Hassall's corpuscles in more than 70% of cases. CONCLUSION: The findings show that VATET without the transcervical approach could be an immunologically incomplete treatment for myasthenia gravis. Therefore, the transcervical approach should be included in VATET procedures to ensure radicality.

Adult↗
PubMed2006

Sulfidation treatment of copper-containing plating sludge towards copper resource recovery.

The present study is concerned with the sulfidation treatment of copper-containing plating sludge towards copper resource recovery by flotation of copper sulfide from treated sludge. The sulfidation treatment was carried out by contacting simulated or real copper plating sludge with Na(2)S solution for a period of 5 min to 24 h. The initial molar ratio of S(2-) to Cu(2+) (S(2-) to Me(2+) in the case of real sludge) was adjusted to 1.00, 1.25 or 1.50, while the solid to liquid ratio was set at 1:50. As a result, it was found that copper compounds were converted to various copper sulfides within the first 5 min. In the case of simulated copper sludge, CuS was identified as the main sulfidation product at the molar ratio of S(2-) to Cu(2+) of 1.00, while Cu(7)S(4) (Roxbyite) was mainly found at the molar ratios of S(2-) to Cu(2+) of 1.50 and 1.25. Based on the measurements of oxidation-reduction potential, the formation of either CuS or Cu(7)S(4) at different S(2-) to Cu(2+) molar ratios was attributed to the changes in the oxidation-reduction potential. By contrast, in the case of sulfidation treatment of real copper sludge, CuS was predominantly formed, irrespective of S(2-) to Me(2+) molar ratio.

Copper↗
PubMed2006

Brain metabolic changes associated with predispotion to onset of major depressive disorder and adjustment disorder in cancer patients--a preliminary PET study.

OBJECTIVES: To explore neurobiological risk factors for major depressive disorder (MDD) and adjustment disorder in cancer patients by examining regional brain metabolism before psychiatric manifestation using positron emission tomography and by prospectively observing depressive and anxiety symptoms. METHOD: Cancer patients who showed no psychiatric symptoms when they underwent 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) were followed up for one year using the Hospital Anxiety and Depression Scale (HADS). Fourteen patients who showed high HADS scores and 14 patients who showed low HADS scores were assessed by a psychiatrist 2 years after the PET scan and grouped into the deterioration group (n=10) and the no-change group (n=9). 18F-FDG PET images were analyzed to examine the difference in local brain glucose metabolism between the two groups. RESULTS: The deterioration group showed a decreased glucose metabolism in the right medial frontal gyrus (BA6) and an increased glucose metabolism in the right posterior cingulate (BA29), right anterior cingulate (BA25), left subcallosal gyrus (BA25), and left caudate compared with the no-change group. CONCLUSION: Cancer patients who later developed MDD or adjustment disorder showed regional brain metabolic changes. These regions may be associated with vulnerability to the onset of MDD or adjustment disorder in cancer patients.

Adjustment Disorders↗
PubMed2006

Laparoscope-assisted anal sphincter-preserving operation preceded by transanal procedure.

BACKGROUND: Transanal intersphincteric resection (ISR) was introduced and has been increasingly performed as an ultimate surgical treatment for extremely low rectal cancer. We considered that high quality and less invasive surgery could be achieved if ISR and laparoscopic surgery were combined. METHODS: Between December 2003 and June 2004, we performed laparoscope-assisted ISR for two patients with very low rectal cancer and total colectomy for two patients with ulcerative colitis complicated by colorectal cancer. In all patients, the transanal procedure was preceded by trans-abdominal laparoscopic rectal excision. RESULTS: Preceding transanal dissection facilitated muscle layer-oriented curative dissection, and more importantly, made subsequent laparoscopic rectal excision effortless as a result of penetrating to the dissected pelvic cavity. All patients showed favorable recovery including postoperative anal function with no complication or recurrent disease. CONCLUSIONS: This procedure is feasible and has favorable short-term results for radical treatment of very low rectal disease, while preserving anal function.

Anal Canal↗
PubMed2006

Sulfidation of zinc plating sludge with Na2S for zinc resource recovery.

A high amount of zinc disposed in the landfill sites as a mixed-metal plating sludge represents a valuable zinc source. To recover zinc from the plating sludge, a sulfidation treatment is proposed in this study, while it is assumed that ZnS formed could be separated by flotation. The sulfidation treatment was conducted by contacting simulated zinc plating sludge with Na(2)S solution at S(2-) to Zn(2+) molar ratio of 1.5 for a period of 1-48 h, while changing the solid to liquid (S:L) ratio from 0.25:50 to 1.00:50. The conversion of zinc compounds to ZnS was determined based on the consumption of sulfide ions. The reaction products formed by the sulfidation of zinc were identified by X-ray diffraction (XRD). As a result, it was found that the conversion of zinc compounds to ZnS increased with an increase in S:L ratio. A maximum conversion of 0.809 was obtained at an S:L ratio of 1.00:50 after 48 h. However, when the zinc sludge treated at S:L ratio of 1.00:50 for 48 h was subjected to XRD analyses, only ZnS was identified in the treated zinc sludge. The result suggested that the rest of zinc sludge remained unreacted inside the agglomerates of ZnS. The formation behavior of ZnS was predicted by Elovich equation, which was found to describe the system satisfactorily indicating the heterogeneous nature of the sludge.

Electroplating↗
PubMed2006

Food webs: experts consuming families of experts.

Food webs of habitats as diverse as lakes or desert valleys are known to exhibit common "food-web patterns", but the detailed mechanisms generating these structures have remained unclear. By employing a stochastic, dynamical model, we show that many aspects of the structure of predatory food webs can be understood as the traces of an evolutionary history where newly evolving species avoid direct competition with their relatives. The tendency to avoid sharing natural enemies (apparent competition) with related species is considerably weaker. Thus, "experts consuming families of experts" can be identified as the main underlying food-web pattern. We report the results of a systematic, quantitative model validation showing that the model is surprisingly accurate.

Animals↗
PubMed2006

Carbon dioxide insufflation attenuates parietal blood flow obstruction in distended colon: potential advantages of carbon dioxide insufflated colonoscopy.

BACKGROUND: Bowel distention after colonoscopy has been considered as a cause of blood flow disturbance. Carbon dioxide (CO2), with its higher absorbability and vasodilating effect, may reduce parietal blood flow disturbance of distended colon when used for intraluminal insufflation instead of air. The purpose of this study was to assess parietal blood flow of the colon distended with intraluminal air/CO2 insufflation. METHODS: A 5-cm segment of rat colon was insufflated with either air (air group) or CO2 (CO2 group). Two insufflation methods were employed: temporary insufflation up to an intraluminal pressure of 60 mmHg and continuous insufflation at a pressure of 5, 15, and 30 mmHg. Bowel distention and parietal blood flow measured by laser Doppler imaging were evaluated. RESULTS: For temporary insufflation, bowel distention was prolonged in the air group, whereas it rapidly resolved in the CO2 group. Parietal blood flow decreased in both groups; however, it recovered within 5 min in the CO2 group. For continuous insufflation, under 5 mmHg insufflation, blood flow decreased in the air group, whereas it increased in the CO2 group. Blood flow decreased in both groups under 15 mmHg insufflation; however, it decreased less in the CO2 group. There was a reverse relationship between insufflation pressure and blood flow difference. Inhibition of nitric oxide synthase, ATP-sensitive K+ channel, or heme oxygenase was ineffective against a CO2-induced increase in blood flow. CONCLUSION: CO2 insufflation preserved parietal blood flow not only by rapid resolution of bowel distention but also by its potential vasodilative effect.

Air↗
PubMed2006

Inhibition of donor-derived T cells trafficking into target organs by FTY720 during acute graft-versus-host disease in small bowel transplantation.

In small bowel transplantation (SBTx), graft-versus-host disease (GVHD) is mediated by donor-derived T cells recognizing host major histocompatibility complex (MHC) alloantigens, and represents an important immunological event influencing life in experimental and clinical situations. We evaluated the possibility that a new sphingosine 1-phosphate receptor agonist, FTY720, could diminish GVHD in a rat SBTx model through traffic alteration of donor-derived T cells in target organs. Heterotopic SBTx was performed using a parent (WF)-into-F(1) (WF x ACI) rat combination. Recipient survival, body weight, histopathology, donor-derived T cell subpopulation and cytokine production were compared with untreated controls. FTY720 inhibited lethality and histopathological changes in target organs when administered at 0.5 mg/kg, possibly due to sequestration of donor-derived T cells in the intestinal graft. FTY720 caused a significant reduction in donor T cell numbers in target organs by promoting these cells to home into donor, but not recipient, secondary lymphoid tissues. FTY720 significantly decreased production of interferon (IFN)-gamma in target organs. These findings indicate that FTY720 effectively reduced recirculation of activated donor-derived T cells and recruitment to target organs in GVHD, and was also associated with down-regulated IFN-gamma production. These properties may offer the potential to treat ongoing GVHD in SBTx.

Acute Disease↗
PubMed2006

Antigen clearing from porcine heart valves with preservation of structural integrity.

Bioprostheses currently used for replacement of diseased cardiovascular tissue are preserved and partially protected from immune rejection through chemical fixation. However, after implantation, chemically preserved (fixed) material has limited durability and lacks the ability to revitalize through cellular ingrowth and remodeling. As an alternative to fixation, we aimed at thoroughly removing antigens from tissue, leaving an intact scaffold, suitable for integration and revitalization in the host. Extensive washing of porcine heart valves with a mixture of two detergents (SDS and Triton X-100) yielded an intact matrix devoid of cells and depleted of soluble proteins that was minimally immunogenic in rabbits. A detailed characterization of the biomechanics and durability of the tissue is under way. If the lack of immunogenicity is confirmed in primates, our results would suggest that a detergent-washed, unfixed porcine heart valve can be an attractive non-inflammatory scaffold for heart valve regeneration in humans.

Animals↗
PubMed2006

Establishment of a GIS monitoring system for schistosomiasis japonica in Kofu, Japan.

Although the incidence of human infection with Schistosoma japonicum in Japan fell to zero in 1977, the threat of the possible re-emergence of the disease caused by this trematode still exists. Surveillance of the parasite's intermediate host, Oncomelania nosophora, in Kofu basin therefore began in 1996. A simple, new method for monitoring O. nosophora in an at-risk area in Kofu, which is based on a geographical information system (GIS), was established. At each monitoring site (of which there were 120 from 1996 until 2000, and 60 from 2001 until 2003), the O. nosophora in two quadrats, each measuring 25 x 25 cm, were collected. During the study, the exact location of each site was determined using a hand-held global-positioning system (GPS). This allowed all the sites to be digitally mapped, so that anyone with a hand-held GPS could and can reach each site. The snail and location data were processed using commercial GPS/GIS software packages and used to create a risk map for schistosomiasis re-emergence. Although all snails collected between 1996 and 2003 were uninfected, the proportion of investigated sites in which O. nosophora was detected increased from 36.7% in 1996 to 56.7% in 2003. The mean number of O. nosophora collected per snail-positive site fluctuated widely, between 8.2 and 57.4, in each calendar year. Over the study period there appeared to be a shift southwards in the areas with high densities of O. nosophora. The present results indicate that it is possible to utilize a GIS-based method for the long-term monitoring of the possible re-emergence of schistosomiasis japonica in Japan.

Agriculture↗
PubMed2006

Chronic hypoxia alters calbindin D-28k immunoreactivity in lingual and laryngeal taste buds in the rat.

The distribution and abundance of the calcium binding protein, calbindin D-28k (CB) immunoreactivity in the taste buds of the circumvallate papillae and larynx were compared between normoxic and chronically hypoxic rats (10% O2 for 8 weeks). In the normoxic rats, CB immunoreactivity was observed in some cells and fibers of the intragemmal region of the taste buds in the circumvallate papillae. In contrast, in the subgemmal region of the laryngeal taste buds, fibers but not cells were immunoreactive for CB. In chronically hypoxic rats, CB immunoreactive cells and fibers in the taste buds were decreased in the circumvallate papillae. In the laryngeal taste buds, the density of the subgemmal CB immunoreactive fibers in chronically hypoxic rats was greater than in normoxic rats. It is considered that function of the laryngeal taste buds is different from that of the lingual taste buds, so that laryngeal taste buds may be involved in chemosensation other than taste. The altered density of CB immunoreactive cells and fibers in the lingual and laryngeal taste buds is a predominant feature of hypoxic adaptation, and chronic hypoxic exposure might change the chemical sensitivity of the circumvallate papillae and larynx through the regulation of intracellular Ca2+.

Adaptation, Physiological↗
PubMed2006

An attempt to study the economic loss arising from Schistosoma japonicum infection and the benefits derived from treatment.

From the northern and southern portions of Leyte Province, which are endemic for schistosomiasis, a total of 801 infected individuals were interviewed, examined, and classified into mild, moderate, severe and very severe forms of disease with an assumed loss of working capacity for each category. The frequency rate or number of spells of illness for the past year under observation were correlated with the degree of incapacity to get the total days lost per person per year. Following a series of computations, of which the disability rate was considered as the most important, a total of 45.4 days lost per infected person per year was arrived at. Treatment of the disease with praziquantel was carried out and the patients were followed up one year after treatment, at which time the same methodology was applied. The results show that the 45.4 days lost prior to treatment went down to 4 days lost. There was an economic gain of 41.4 days as a result of treatment. This can be expressed in terms of financial value if we consider half of the infected cases as breadwinners receiving a minimum wage. It should be noted that a number of assumptions in this study were made. It is, however, hoped that this work will serve as a guide and a starting point for others to carry out related studies on economic loss and subsequent economic benefits to justify budgetary requests/allocations for the implementation of various preventive and control measures.

Adolescent↗
PubMed2005

The transcriptional landscape of the mammalian genome.

This study describes comprehensive polling of transcription start and termination sites and analysis of previously unidentified full-length complementary DNAs derived from the mouse genome. We identify the 5' and 3' boundaries of 181,047 transcripts with extensive variation in transcripts arising from alternative promoter usage, splicing, and polyadenylation. There are 16,247 new mouse protein-coding transcripts, including 5154 encoding previously unidentified proteins. Genomic mapping of the transcriptome reveals transcriptional forests, with overlapping transcription on both strands, separated by deserts in which few transcripts are observed. The data provide a comprehensive platform for the comparative analysis of mammalian transcriptional regulation in differentiation and development.

3' Untranslated Regions↗
PubMed2005

Some properties of the speciation model for food-web structure-mechanisms for degree distributions and intervality.

We present a mathematical analysis of the speciation model for food-web structure, which had in previous work been shown to yield a good description of empirical data of food-web topology. The degree distributions of the network are derived. Properties of the speciation model are compared to those of other models that successfully describe empirical data. It is argued that the speciation model unifies the underlying ideas of previous theories. In particular, it offers a mechanistic explanation for the success of the niche model of Williams and Martinez and the frequent observation of intervality in empirical food webs.

Animals↗
PubMed2005

Approach for simultaneous measurement of two-dimensional angular distribution of charged particles: spherical aberration correction using an ellipsoidal mesh.

An approach for simultaneous measurement of two-dimensional angular distribution of charged particles is proposed. This concerns spherical aberration correction in electrostatic lenses with potential use of a mesh. In an earlier work, an effective use of a spherical mesh has succeeded to obtain a large acceptance angle limited to around 60 degrees (+/- 30 degrees). The present work is aimed at dramatically increasing acceptance angles limited in conventional lenses. For this purpose, spherical aberration behavior of mesh lenses is studied in detail using an analytical approximation and ray tracing, with particular attention paid to the effect of the mesh shape. It is shown here that the lens ability to correct spherical aberration over wide aperture angles can be effectively enhanced by the ellipsoidal deformation of a spherical mesh. We demonstrate that an effective use of an ellipsoidal mesh provides remarkable performance characteristics for electrostatic lenses, which opens new possibilities in surface and materials analysis techniques. Simple examples of ellipsoidal mesh lenses are presented that allow very wide acceptance angles of up to 120 degrees.

Journal Article↗