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Biomedical subjects

M Kuroda

Publications and source records attributed to M Kuroda.

At least 19 recordsLinked to original sources
PubMed2006

Mucinous adenocarcinoma associated with chronic anal fistula reconstructed by gracilis myocutaneous flaps.

Mucinous adenocarcinoma associated with chronic anal fistula is extremely rare, and such tumors have often reached an advanced stage at the time of presentation. Here we report a case of mucinous adenocarcinoma associated with chronic anal fistula that involved repair with gracilis myocutaneous flaps and review other reported cases. A 67-year-old man with an approximate 30-year history of an anal fistula was referred to our hospital due to enlargement of the perianal induration accompanied by mucinous secretion and pain. Physical examination of the perianal region revealed an ulcerated and discharging lesion on the buttocks. Histologic examination of a biopsy specimen of the ulcerated lesion revealed mucinous adenocarcinoma. An abdominoperineal resection was performed with resection of the ischiorectal fossa, coccyx, part of the gluteus maximus, and the obturator internus. The extensive defect was repaired with bilateral gracilis myocutaneous flaps. The patient did not experience a decrease in the strength of hip adduction and survived for 58 months without recurrence until he died of pneumonia. The repair using myocutaneous flaps was considered to contribute to a physically active life without recurrence.

Adenocarcinoma, Mucinous↗
PubMed2006

Effective sludge solubilization treatment by simultaneous use of ultrasonic and electrochemical processes.

Sludge disintegration treatment by using simultaneously ultrasonic irradiation and electrolysis was investigated experimentally. A lab-scale diaphragm cell irradiated with ultrasound at a constant oscillating frequency of 20 kHz was used as a reactor. The batch experiments were carried out under different conditions of electric outputs of the ultrasonic generator, electric current for the electrolysis and different initial SS concentrations. A simultaneous treatment in the cathodic compartment without any chemical doses considerably facilitated the sludge solubilization, compared to the sonication alone. An increase in the electric current up to 400 mA under a constant ultrasonic density decreased the specific energy by 55% within the experimental range. The specific energy consumption was also reduced when the initial SS concentration increased. In addition, before carrying out the simultaneous treatment, a brief electrolysis was effective for further reduction of the specific energy and the acceleration of soluble COD generation.

Electrochemistry↗
PubMed2005

Dual axonal terminations from the retrosplenial and visual association cortices in the laterodorsal thalamic nucleus of the rat.

Light and electron microscopic tracing studies were conducted to assess the synaptic organization in the laterodorsal thalamic nucleus (LD) of the rat and the laminar origins of corticothalamic terminals from the retrosplenial and visual association cortices to LD. A survey of the general ultrastructure of LD revealed at least three types of presynaptic terminals identified on the basis of size, synaptic vesicle morphology, and synaptic membrane specializations: (1) small axon terminals with round synaptic vesicles (SR), which accounted for the majority of terminal profiles and made asymmetric synaptic contacts predominantly with small dendritic shafts and spines; (2) large axon terminals with round synaptic vesicles (LR), which formed asymmetric synaptic contacts mainly with large dendritic shafts; and (3) small to medium-size axon terminals with pleomorphic synaptic vesicles (SMP), which symmetrically synapsed with a wide range of postsynaptic structures from cell bodies to small dendrites. Synaptic glomeruli were identified, whereas no presynaptic dendrites were found. To characterize and identify corticothalamic terminals arising from the retrosplenial and visual association cortices that project to LD, wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) was injected into these cortices. Axons anterogradely labeled with WGA-HRP ended in both SR and LR terminals. On the other hand, dextran-tetramethylrhodamine injected into LD as a retrograde fluorescent tracer labeled large pyramidal cells of layer V as well as small round or multiform cells of layer VI in the retrosplenial and visual association cortices. These findings provide the possibility that corticothalamic terminations from cortical neurons in layer V end as LR terminals, while those from neurons in layer VI end as SR boutons.

Animals↗
PubMed2005

Comparative study on the bio-electrochemical denitrification equipped with a multi-electrode system.

Three biofilm-electrode reactors (BERs) with multiple cathodes were applied to investigate the effect of electrode configuration and flow direction on denitrification under laboratory-scale conditions. The distribution of nitrate, DO and pH varied among applied BERs, as a consequence of a different electrode position in the reactors, bringing about a difference in the performance. Flow-through configuration of electrodes with a downstream anode appears to be the most suitable configuration since nitrite did not accumulate in the effluent only in this experiment and the current-denitrification efficiency at low current densities was high. Thus, it is recommended for a low-loading operation.

Electrochemistry↗
PubMed2004

Modulated hydrogen beam study of adsorption-induced desorption of deuterium from Si(100)-3x1:D surfaces.

We have studied the kinetic mechanism of the adsorption-induced-desorption (AID) reaction, H+D/Si(100) --> D2. Using a modulated atomic hydrogen beam, two different types of AID reaction are revealed: one is the fast AID reaction occurring only at the beam on-cycles and the other the slow AID reaction occurring even at the beam off-cycles. Both the fast and slow AID reactions show the different dependence on surface temperature Ts, suggesting that their kinetic mechanisms are different. The fast AID reaction overwhelms the slow one in the desorption yield for 300 K < or = Ts < or = 650 K. It proceeds along a first-order kinetics with respect to the incident H flux. Based on the experimental results, both two AID reactions are suggested to occur only on the 3x1 dihydride phase accumulated during surface exposure to H atoms. Possible mechanisms for the AID reactions are discussed.

Journal Article↗
PubMed2004

An orally active matrix metalloproteinase inhibitor, ONO-4817, reduces dextran sulfate sodium-induced colitis in mice.

OBJECTIVE: Over-expression of matrix metalloproteinases (MMPs) can accelerate tissue destruction and disrupt subsequent tissue repair. A dextran sulfate sodium (DSS) colitis model was established to examine the effects of MMP inhibition, by an orally active MMP inhibitor ONO-4847, on colonic inflammation. MATERIALS AND METHODS: Acute colitis was induced in female BALB/c mice by giving 8% DSS orally in drinking water for 7 days. The animals were randomized into groups receiving different concentrations of ONO-4847 or vehicle by oral gavage every day. mRNA levels of 4 MMPs and a tissue inhibitor of MMP (TIMP-1) were measured by RT-PCR in intestinal tissue isolated from mice after DSS administration. Colonic mucosal injury and inflammation were evaluated clinically, biochemically, and histologically. The clinical disease activity index (DAI), including body weight loss, stool consistency, and blood in feces, was examined. Moreover, mucosal tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma were determined by immunoassay. RESULTS: The intestinal expression of MMP-3, -7, 9, and -12 and TIMP-1 mRNA was upregulated after DSS administration. Shortening of the colon was significantly reversed by ONO-4847 at a dose of 30 mg/kg. DAI in DSS-treated mice was significantly lower in the ONO-4847-treated mice compared with the control mice. Histological study also showed a reduced infiltration of inflammatory cells, especially neutrophils, and reducedmucosal cell disruption in ONO-4847-treated mice compared with the control mice. The increases in tissue-associated myeloperoxidase activity and thiobarbituric acid-reactive substances after DSS administration were both significantly inhibited by co-administration with ONO-4847. ONO-4847 also inhibited increases in the mucosal TNF-alpha and IFN-gamma content after DSS administration. CONCLUSION: Improvements in DSS colitis in response to ONO-4847 suggest that activation of MMPs contributes to the initiation/amplification of colonic inflammatory injury by mechanisms including oxidative damage as well as enhancement of inflammatory cytokine release.

Administration, Oral↗
PubMed2004

Interleukin-8 expression in the esophageal mucosa of patients with gastroesophageal reflux disease.

BACKGROUND: It has been reported that inflammatory cell infiltration can be detected in patients with endoscopically negative gastroesophageal reflux disease (GERD) as well as those with erosive reflux esophagitis. In this study, we examined the expression of mRNA for interleukin (IL)-8, a potent chemokine for neutrophils, in the esophageal mucosa of patients with GERD and compared the results with their endoscopic findings and symptoms. METHODS: Biopsy samples were obtained from 80 patients. Endoscopic diagnosis was performed according to the Los Angeles classification. Patients with typical symptoms such as heartburn despite normal endoscopic findings were classified as the non-erosive GERD group. Total cellular RNA was extracted from the biopsy samples and IL-8 mRNA was quantified by real-time polymerase chain reaction (PCR). Localization of IL-8 protein in the esophageal mucosa was done by immunostaining. RESULTS: Expression of IL-8 mRNA was correlated with the endoscopic grade of esophagitis or with inflammatory cell infiltration, but not with the symptoms of the patients. Expression of IL-8 mRNA was also detected in all patients with non-erosive GERD. The level of IL-8 expression in non-erosive GERD was low compared with that in erosive GERD, but was higher than that in normal controls. IL-8 immunostaining was found in the basal layers of the esophageal mucosa. Administration of lansoprazole, a proton-pump inhibitor, decreased both IL-8 mRNA and protein levels in the esophageal mucosa. CONCLUSION: These results suggest that IL-8 in the esophageal mucosa may be involved in the pathogenesis of esophageal inflammation, including non-erosive GERD.

Base Sequence↗
PubMed2004

Reflux esophagitis after eradication of Helicobacter pylori is associated with the degree of hiatal hernia.

BACKGROUND: Several studies have shown that reflux esophagitis (RE) occurs after eradication of Helicobacter pylori. However, endoscopic findings do not allow prediction of the development of RE after successful treatment. In this study, we evaluated the relationship between the prevalence of RE after eradication therapy and the degree of hiatal hernia. METHODS: The study comprised 148 patients who had undergone H. pylori eradication therapy over the past 5 years. The degree of RE and hiatal hernia was evaluated based on endoscopic findings. Hiatal hernia was graded according to Hill's gastroesophageal flap valve (GEFV; grades I-IV) classification. RE after eradication therapy was graded according to the Los Angeles classification system. H. pylori infection was confirmed in all patients by culture, urease test and histological examination of antral and fundic biopsy specimens. RESULTS: Among 148 patients, there were 122 patients (82.4%) with successful and 26 (17.6%) with failed eradication therapy. RE was diagnosed in 25 (20.5%) out of 122 patients with successful therapy but only in 1 (3.8%) out of 26 patients with failed therapy (P < 0.05). After successful eradication, 25 patients had mild RE (12 with grade A, 13 with grade B). Among patients of the successful eradication group (n = 122), RE was diagnosed in 2 (5.3%) out of 38 patients without hiatal hernia and in 23 (27.4%) out of 84 patients with hiatal hernia (P = 0.0051). Furthermore, RE was diagnosed in 2 (5.3%) out of 38 patients with GEFV grade I, 13 (24.1%) out of 54 with grade II, 7 (30.4%) among 23 with grade III, and 3 (42.9%) out of 7 patients with grade IV. The pH level of gastric juice after eradication therapy was lower in the group with successful eradication than in the group with failed therapy regardless of the incidence and degree of RE. CONCLUSIONS: There is a high incidence of RE after successful H. pylori eradication therapy. This incidence of RE was closely associated with the presence and degree of hiatal hernia and with the decrease in gastric juice pH. These findings suggest that the presence of hiatal hernia together with increase in gastric acidity are important determinant factors for the development of RE after successful H. pylori eradication therapy.

Endoscopy, Gastrointestinal↗
PubMed2004

Correlations of hemoglobin index (IHb) of gastric mucosa with Helicobacter pylori (H. pylori) infection and inflammation of gastric mucosa.

BACKGROUND: Helicobacter pylori (H. pylori) infection causes various gastric diseases, among them H. pylori-associated gastritis characterized by diffuse redness of the gastric mucosa. The haemoglobin index (IHb) of the fundic mucosa is an objective parameter of the extent of mucosal redness, but it is unclear whether or not IHb can be used as a diagnostic marker for H. pylori infection. The purpose of this investigation was to evaluate the correlations between IHb of the fundic mucosa and H. pylori infection, inflammatory cell infiltration, and inflammatory mediator production. METHODS: IHb of the fundic mucosa was measured in 108 patients with various gastric diseases (group 1), and values were compared between H. pylori-positive and H. pylori-negative patients. Fifteen patients with H. pylori infection from group 1 underwent H. pylori eradication therapy and IHb was measured before and after treatment. Both IHb and inflammatory cell infiltration were assessed in 61 patients (group 2). In 31 patients from group 2, the expression of interleukin (IL)-8 and inducible nitric oxide synthase (iNOS) messenger RNA (mRNA) was assayed in gastric biopsy specimens by the reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: IHb levels were significantly higher in H. pylori-positive patients than in H. pylori-negative patients (P < 0.001). IHb was decreased at one month after the eradication of H. pylori (P < 0.001). IHb was higher in patients with infiltration by both mononuclear cells and neutrophils (P < 0.001). There was a significant correlation between the IHb level and the expression of IL-8 mRNA (P < 0.001), as well as between IHb and iNOS mRNA expression (P < 0.05). CONCLUSIONS: There were significant correlations between IHb of the gastric mucosa and H. pylori infection, inflammatory cell infiltration, and IL-8/iNOS mRNA expression, suggesting that IHb is a reliable marker of H. pylori infection for use during follow-up endoscopy after H. pylori eradication therapy.

Biomarkers↗
PubMed2004

Development of a phantom compatible for MRI and hyperthermia using carrageenan gel-relationship between T1 and T2 values and NaCl concentration.

The authors developed a phantom, designated as the CAGN phantom, compatible for MRI and hyperthermia that is useful in the fundamental studies of non-invasive MR thermometry. The ingredients of this phantom are carrageenan, GdCl3 as a T1 modifier, agarose as a T2 modifier, NaCl as a conductivity modifier, NaN3 as an antiseptic and distilled water. Another phantom that was developed, the CAG phantom, has relaxation times that are adjustable to those of any human tissue. To use this phantom for electromagnetic heating, NaCl was added to change the conductivity of the phantom and clarified the relationship between the conductivity and NaCl concentration. This study examined the relationship between relaxation times and NaCl concentration of the CAGN phantom. The results showed that both T1 and T2 values were affected by NaCl and the experimental results led to the empirical formulae expressing the relationship between the relaxation rates (1/T1, 1/T2) and the concentrations of GdCl3, agarose and NaCl. The appropriate concentrations of T1 and T2 modifiers were calculated from these empirical formulae when making a specified phantom that has the required relaxation times and NaCl concentration.

Algorithms↗
PubMed2004

Development of a phantom compatible for MRI and hyperthermia using carrageenan gel--relationship between dielectric properties and NaCl concentration.

A phantom has previously been developed containing carrageenan, agarose and gadolinium chloride (called CAG phantom) for MRI with 1.5 T. T(1) and T(2) relaxation times of this phantom are independently changeable by varying concentrations of relaxation-time modifiers to simulate relaxation times of the various types of human tissues. The CAG phantom has a T(1) value of 202-1904 ms and a T(2) value of 38-423 ms, when the GdCl(3) concentration is varied from 0-140 micromol/kg and the agarose concentration is varied from 0-1.6%. A new phantom has now been developed (called CAGN phantom), made by adding an electric conductive agent, NaCl, to the CAG phantom for use in the areas of MRI and hyperthermia research. Dielectric properties of the CAGN phantom were measured and the results of experiments were expressed by the Cole-Cole equation in the frequency range of 5-130 MHz. The relationship between the conductivity of the CAGN phantom and the concentration of NaCl was expressed by a linear function in the frequency range of 1-130 MHz. The linear function involves a parameter of frequency and, when the frequency is 10 MHz, the conductivity of the CAGN phantom can be changed from 0.27-1.26 Sm(-1) by increasing the NaCl concentration from 0-0.7%. The CAGN phantom developed can be employed in basic experiments for non-invasive temperature measurement using MRI and as a loading phantom for MRI with up to 3 T.

Carrageenan↗
PubMed2004

Glomerular expression of biglycan and decorin and urinary levels of decorin in primary glomerular disease.

AIMS: Recent studies have suggested that small leucine-rich proteoglycans (SLRP) of the extracellular matrix play a major role in modulating the activity of growth factors and in regulating the deposition of collagens. In this study, the expression of the SLRPs biglycan and decorin in the glomeruli of patients with primary glomerular disease (minimal change disease, IgA nephropathy, and membranous nephropathy) and urine immunoreactive levels examined. METHODS: Renal biopsy specimens were obtained from patients with minimal change disease, IgA nephropathy and membranous nephropathy. Immunohistochemical staining was performed on fresh-frozen samples using anti-biglycan and anti-decorin antibodies. Examination of urine proteoglycan excretion from a total of 26 patients and 8 normal volunteers was performed by indirect ELISA. RESULTS: In normal kidney samples, biglycan and decorin expression was found predominantly in the intrarenal arteries and tubulointerstitium, with only minimal expression in the glomeruli. Glomerular expression of these proteoglycans in glomerular disease was unchanged in all of the 4 patients examined with minimal change disease. In the case of IgA nephropathy or membranous nephropathy, some of the patients showed minimally increased immunostaining of either biglycan or decorin, but there were no signs of simultaneous upregulation of both proteoglycans. To further examine the changes in proteoglycan expression, ELISA was performed on urine samples. Urine biglycan levels were below detection levels, but high values of urine decorin immunoreactivity were found in the patients with glomerular disease. A significant negative correlation was found between urine decorin and creatinine clearance. CONCLUSION: These results suggest that distinct changes in the expression of the SLRPs biglycan and decorin may be seen in patients with primary glomerular disease. Moreover, the negative relationship between urine decorin levels and renal function supports the hypothesis that decorin may be involved in the pathophysiology of renal dysfunction in humans.

Adult↗
PubMed2004

Application of a bio-electrochemical reactor process to direct treatment of metal pickling wastewater containing heavy metals and high strength nitrate.

The fundamental performance of a bio-electrochemical reactor for the direct treatment of metal pickling wastewater was investigated experimentally. In the reactor, carbon anode and cathode were installed. On the cathode, denitrifying microorganisms were immobilized. Continuous experiments were carried out by feeding a synthetic wastewater containing nitrate and binary heavy metal ions, copper and lead, under different operating conditions. Acetate as well as the electric current was supplied at the minimum amount for stoichiometry of the dissimilatory denitrification reaction. The results indicated that the dissolved copper and lead removal, denitrification and neutralization could be achieved simultaneously in a single bio-electrochemical reactor. The dissolved heavy metals were removed by electrochemical deposition on cathode and by the other phenomena such as the formation of insoluble suspensions and the sorption on suspended bacterial sludge. Denitrification proceeded effectively with the utilization of both added acetate and hydrogen gas generated by electrolysis of water. The pH value increased up to around neutral due to the occurrence of denitrification in the reactor, although the influent pH was less than 3. The removal efficiencies of heavy metals and nitrate increased with increasing the current density. The applied electric current was indispensable for sustaining the stable treatment in the reactor.

Acetates↗
PubMed2003

Follicular dendritic cell tumor in the oro-pharyngeal region: report of a case and a review of the literature.

A case of follicular dendritic cell tumor (FDC tumor) arised in the aro-pharyngeal region is reported in a 16-year-old Japanese boy. He had a swelling in the right retromolar trigone and soft palate. Clinical examination disclosed a 25 mm x 30 mm, elastic hard, ulcerated mass. CT scans showed a low density lesion in the right medial parapharyngeal area. The biopsy specimen revealed a low-grade malignant tumor. The patient underwent a tumorectomy which was extended to include the adjacent palatine tonsil. The tumor cells, with a clear cytoplasm and oval nucleus, were immunoreactive for S-100 (N/A), CD 21 (1F8), fascin (55K-2) and FDC (CNA42). The fascicular sheet pattern arrangement of the tumor cells was partly characteristic. The final diagnosis was an follicular dendritic cell tumor. Three courses of adjuvant chemoradiotherapy were administered postoperatively. Clinical features, pathological diagnosis and immunohistochemical markers for distinguishing FDC tumor are reviewed.

Adolescent↗
PubMed2002

The effect of the physical structure of a porous Ca-based sorbent on its phosphorus removal capacity.

A macroporous calcium-based sorbent made from bentonite, calcium hydroxide and Yalloun coal was prepared and tested for its phosphorus removal performance. The coal was added as a solid pore-forming agent. Pores sizes as large as a few micron were generated when the Yalloun coal was incorporated at a relatively high proportion. These pores were formed due to the burning out of the added coal during the thermal treatment conducted at 700 degrees C. Results of phosphorus removal experiments showed that the increase of the amount of phosphorus removed could be positively correlated with the increase of the total pore volume and the mean pore size. Decreases in pore sizes and total pore volume were pronounced in sorbents used to remove phosphorus due to the formation of a Ca-phosphate mineral on their surfaces. It was suggested that the widely formed pores avoided the rapid plugging and contributed to maintain the diffusional transport of the substrate to a certain extent. Hydroxyapatite was formed and coated on the surface of the sorbent during phosphorus removal. On the basis of these results, it was concluded that modification of the physical structure of Ca-based sorbents by creating large pore sizes, revealed to be effective for increasing their phosphorus uptake.

Adsorption↗
PubMed2002

Increase of gamma-glutamyl-beta-alanyl-histidine isopeptide in the macromolecular fraction of model chicken extract during heating and distribution in commercial chicken extracts.

Changes in the amino acid composition and contents of gamma-glutamyl-beta-alanyl-histidine isopeptide in the macromolecular fraction were measured during heating of chicken extract. Increases of histidine, 1-methylhistidine, and beta-alanine were observed, suggesting that carnosine and anserine were incorporated into the macromolecular fraction. The increase of gamma-glutamyl-beta-alanylhistidine isopeptide in the macromolecular fraction of chicken extract was also observed during the heating process. Furthermore, measurement of gamma-glutamyl-beta-alanylhistidine isopeptide in commercial chicken extract showed that all kinds of chicken extract contained the above isopeptide (from 0.09 to 0.31 micromol/g DM in the macromolecular fraction). These results suggest that the formation of gamma-glutamyl-beta-alanyl-histidine and related isopeptides occur during heating of chicken extract.

Animals↗