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Biomedical subjects

H Sato

Publications and source records attributed to H Sato.

At least 91 records · Page 5Linked to original sources
PubMed2003

Differential relationship between changes in tumour size and microcirculatory functions induced by therapy with an antivascular drug and with cytotoxic drugs. implications for the evaluation of therapeutic efficacy of AC7700 (AVE8062).

A novel combretastatin A-4 derivative, AC7700, which is now in Phase I clinical trials under a new code, AVE8062, has shown strong antitumour effects against solid tumours in rodents because of its powerful and continued stanching of the tumour blood flow (TBF). Despite the strong tumour-suppressing qualities of AC7700, it does not produce an immediate reduction in tumour size. To elucidate the reason for this effect, we investigated the relationship between the change in tumour size in Sato lung carcinoma (SLC) and circulatory functions after therapy with AC7700, doxorubicin (Adriamycin [ADR]), or mitomycin C (MMC). To measure time-lapse changes in TBF with the hydrogen clearance method at the same site after drug administration, we developed a new apparatus for keeping electrodes within a tumour. AC7700 led to the destruction of both cancer cells and tumour vessels by interrupting the supply of nutrients. Intravenous (i.v.) administration of fluorescent dyes after AC7700 treatment revealed no fluorescence within the tumour vessels, which confirmed that the tumour microcirculation had been completely blocked. In contrast, ADR led to the destruction of SLC tumour cells, but did not have the same effect on tumour vessels. Intravenously administered fluorescent dyes immediately reached the tumour, which indicated that the tumour vasculature remained intact, and the TBF remained at the preadministration level, even 6 days after ADR treatment. In addition, although the size of the tumour increased slightly for 2 days with ADR treatment, possibly because of swelling of the cancer cells, thereafter it continued to decrease. MMC had virtually no effect on SLC tumour cells, tumour size or tumour vessels. We conclude that changes in tumour size brought about by cancer chemotherapy depend not only on the sensitivity of the cancer cells to the drug in question, but also on the nature of changes in the microcirculatory functions of the tumour brought about by the therapy. When both tumour cells and the tumour vasculature are destroyed, the effectiveness of therapy can not be determined from changes in tumour size alone.

Animals↗
PubMed2003

Ultrasonographic imaging of experimentally induced pancreatitis in cattle.

This study was conducted to determine the ultrasonographic patterns of pancreatitis evoked in cattle, with reference to laboratory and pathological findings. Using ultrasonographic guidance, acute necrotizing pancreatitis was induced in six cows by injecting chloroform into the pancreatic tissue. Ultrasonographic examination was then performed once daily for nine days. Pancreatic lesions were visible 24h after induction of pancreatitis, as represented by a uniform increase in echogenicity and by intralobular and subcapsular fluid accumulation. As the experiment progressed, patchy hypoechogenic foci appeared within the gland parenchyma. Amylase and lipase activities showed rapid increases. Post mortem examination revealed gross and microscopic necrotic and haemorrhagic lesions in the body and right lobe of the pancreas, accompanied by oedema and fibrosis. Ultrasonography was found to be extremely useful for the detection and characterization of experimentally induced pancreatitis and to monitor its progression in the cow. These findings are of potential value as a reference for the diagnostic workup of bovine pancreatitis, and ultrasonography is seen as a promising non-invasive technique for the diagnosis of suspected pancreatitis in cattle.

Animals↗
PubMed2003

Transcutaneous ultrasound-guided pancreatic biopsy in cattle and its safety: a preliminary report.

This study describes a free-hand technique for percutaneous pancreatic biopsy in cattle with ultrasound-guidance using a 14G spinal biopsy needle. Its safety was evaluated based on 36 consecutive procedures. To assess the immediate effects of pancreatic biopsy, 31 cows were necropsied shortly after the procedure and examined. The remaining five cows were examined daily for eight days and then necropsied and examined. No life-threatening complications nor clinically detectable abnormalities were observed. Changes indicative of inflammation were not apparent in total and differential WBC counts or in total protein and fibrinogen concentrations. A small increase of amylase activity was detected in only one cow kept for the eight-day observation period. Serum lipase activity increased significantly on day four after biopsy. Urea nitrogen, creatinine, glucose and the activities of aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyltransferase remained within reference ranges. Changes in the peritoneum and pancreas observed at necropsy were negligible. We conclude that percutaneous ultrasound-guided pancreatic biopsy did not appear to influence the cow's condition adversely and the procedure provided an excellent method of obtaining a pancreatic specimen for histological examination. The procedure was considered safe, fast, cost-effective, and practical when performed properly. We believe that the technique can be used in cows with suspected pancreatic disease for making an ante mortem diagnosis.

Animals↗
PubMed2003

Monoclonal IgA antibody-mediated expulsion of Trichinella from the intestine of mice.

To assess the potential role of IgA antibody in expulsion of the nematode of the genus Trichinella from the intestine, a panel of IgA monoclonal antibodies (mAbs) were produced from the mesenteric lymph node cells from BALB/c mice orally vaccinated with irradiated muscle larvae of Trichinella britovi. One IgA mAb, HUSM-Tb1, formed immunoprecipitates on the surface of live muscle larvae, and by immunohistochemistry reacted with their stichocytes and cuticular surface, but not with those tissues of the adult stage or newborn larvae. Intraperitoneal injection of BALB/c mice with this mAb 5 h before challenge conferred a high level of protection (more than 95%) against T. britovi infection, when 2.0 mg of specific IgA/20 g body weight was given to a mouse. The same treatment produced a similar effect in SCID mice lacking functional T- and B-cells, indicating no requirement of synergistc T-cell factors for the effect. Passive transfer of the mAb at the time of challenge or later showed less or no effect upon worm expulsion. It is concluded that the mucosal IgA response, when adequately induced, can impede the establishment of infective Trichinella parasites in the mouse intestine.

Animals↗
PubMed2003

Persistent infection of Mongolian jirds with a non-pathogenic trypanosome, Trypanosoma (Herpetosoma) grosi.

Non-pathogenic trypanosomes of the subgenus Herpetosoma are normally host specific, and laboratory models include Trypanosoma lewisi in rats and Trypanosoma musculi in mice. Two isolates of Trypanosoma grosi, originating from Apodemus agrarius and Apodemus peninsulae, grew well in Mongolian jirds, Meriones unguiculatus, after intraperitoneal inoculation of 2 x 10(5) or a minimum 500 bloodstream forms. The course of T. grosi infection in jirds resembled T. musculi infection in mice, rather than T. lewisi infection in rats. At week 2 to 3 p.i. trypanosomes disappeared from the bloodstream, and neither prednisolone treatment nor splenectomy prevented parasite elimination from the bloodstream. However, these treatments induced a marked increase in peak parasite counts. Regardless of prednisolone treatment or splenectomy, all jirds after day 21 p.i. became resistant to the reinfection. Although no trypanosomes were detected in the bloodstream of recovered jirds, dividing parasites persisted in the medullary capillaries of the kidney, like T. musculi infection in mice. We propose the T. grosi infection in jirds as an additional laboratory model for the study of non-pathogenic trypanosomes.

Animals↗
PubMed2003

Co-occurrence of three different mutations in the bilirubin UDP-glucuronosyltransferase gene in a Chinese family with Crigler-Najjar syndrome type I and Gilbert's syndrome.

Crigler-Najjar syndrome type I is a severe form of hereditary unconjugated hyperbilirubinemia and is caused by homozygous or compound heterozygous mutations of the bilirubin UDP-glucuronosyltransferase gene (UGT1A1). We analyzed the bilirubin UDP-glucuronosyltransferase gene in a female Chinese patient with Crigler-Najjar syndrome type I. Relatives of the patient were also analyzed. The patient was homozygous for a nonsense mutation of R341X. The patient's father, sister and brother, all diagnosed with Gilbert's syndrome, were compound heterozygotes of R341X, P229Q, and an insertion mutation of the TATA box [A(TA)7TAA]. Heterozygotes of nonsense mutations (Q331X and C280X) in our previous study had either Crigler-Najjar syndrome type II or Gilbert's syndrome, but heterozygotes of R341X (mother and grandmothers) were normal. An in vitro expression study of homozygous and heterozygous models of R341X showed 0 and 58%, respectively, of normal enzyme activity. Therefore, the present results indicate that carriers of the nonsense mutation could be normal for plasma bilirubin concentration, Gilbert's syndrome and Crigler-Najjar syndrome type II. The results also suggest the importance of the accumulation of prevalent or polymorphic mutation in the etiology of Gilbert's syndrome and Crigler-Najjar syndrome type II.

Adult↗
PubMed2003

Serum stem cell growth factor for monitoring hematopoietic recovery following stem cell transplantation.

Stem cell growth factor (SCGF) is a novel cytokine for primitive hematopoietic progenitor cells. Although it has burst-promoting activity and granulocyte/macrophage colony-promoting activity in vitro, its significance in hematopoiesis in vivo has not been elucidated. In this study, we have established enzyme-linked immunosorbent assay (ELISA) to quantify human SCGF and measured serum cytokines in normal volunteers and 27 patients undergoing stem cell transplantation (SCT), including six autologous and 21 allogeneic transplants. SCGF levels gradually increased after SCT regardless of graft-versus-host disease or type of transplant. The maximum level of SCGF was observed during the rapid granulocyte recovery phase in patients subjected to an autologous transplantation, and during the granulocyte stabilization phase in allogeneic patients. SCGF levels in PBSCT patients began to rise earlier than in BMT patients. Two patients with no increment of SCGF after SCT showed delayed engraftment. The source of SCGF was further analyzed by RT-PCR and we found that SCGF was highly expressed in bone marrow (BM) CD34(+) and CD34(-)CD33(+) cells, but not in BM CD34(-)CD33(-) cells, BM stromal cells and peripheral blood cells. The cell population expressing SCGF in BM possess the colony-forming cell activity. Therefore, serum SCGF can be an indicator of hematopoietic recovery following SCT.

Adolescent↗
PubMed2003

Inhibitor kappa B-alpha (IkappaB-alpha) promoter polymorphisms in UK and Dutch sarcoidosis.

The aetiology of sarcoidosis is uncertain; current thinking implicates exposure of genetically susceptible hosts to environmental factors. The nuclear factor kappa B (NF-kappaB) family of transcription factors are critical regulators of immediate transcriptional responses in inflammatory situations and immune responses. Inhibitor kappa B-alpha (IkappaB-alpha) inhibits NF-kappaB and plays a major role in controlling its activity. We investigated IkappaB-alpha promoter polymorphisms using sequence-specific primer-polymerase chain reaction, at positions -881 (A/G), -826 (C/T), and -297 (C/T) in Caucasian sarcoidosis patients (UK and Dutch [NL]), each with their own controls. Disease severity at presentation was assigned using chest radiography and pulmonary function indices. In the combined populations, the -297T allele carriage was more prevalent in patients than in controls (P=0.008). Three common haplotypes were found, of which haplotype 2 (GTT) was significantly associated with sarcoidosis in comparison with control subjects (P=0.01). Subgroup analysis revealed that the -826T allelic carriage was most prevalent in stage II disease, and more prevalent in stage III than in stage IV (P=0.01). The -826T allelic carriage did not show any association with lung function. These results indicate that the NF-kappaB activation pathway might be associated with the inflammation of sarcoidosis.

Disease Progression↗
PubMed2003

Effects of staphylococci on cytokine production from human keratinocytes.

BACKGROUND: Staphylococcus skin infection is characterized by the infiltration of numerous neutrophils within the epidermis; however, the precise mechanism of epidermal infiltration of neutrophils during skin infection with staphylococci is not well understood and the factors regulating the neutrophil recruitment are yet to be determined. OBJECTIVES: We investigated the effects of staphylococci on cytokine production from keratinocytes, specifically to elucidate the mechanisms of neutrophil infiltration within the epidermis in cutaneous microbial infection. METHODS: Cytokine production from human keratinocytes was examined after stimulation with heat-killed Staphylococcus aureus, S. epidermidis and S. intermedius. RESULTS: Interleukin (IL)-6 and IL-8 were detected in the culture supernatants by enzyme-linked immunosorbent assay but IL-1beta, monocyte chemotactic protein-1 and tumour necrosis factor-alpha were not. IL-6 and IL-8 mRNAs were also confirmed by reverse transcription-polymerase chain reaction in the keratinocytes stimulated with killed staphylococci for 1, 3, 6, 10 and 24 h. CONCLUSIONS: These results could explain the epidermal infiltration of neutrophils in cutaneous infection with staphylococci, suggesting that the analysis of cytokines might add valuable information for the pathogenesis of cutaneous infection with Staphylococcus species.

Cells, Cultured↗
PubMed2003

A new and simple method for evaluating masticatory function using newly developed artificial test food.

The aim of this study was to develop an objective evaluation system for the masticatory function. This system used paraffin wax cubes as a test food, which had six red- and green-coloured layers so that each of the six surfaces showed a pseudo-checkered pattern. A total of 100 paraffin cubes were chewed by 37 subjects and the images of these samples were captured and analysed using a digital image analyzer. With regard to the colour and the shape of each sample, five parameters were obtained. Furthermore, an independent examiner graded the degree of colour mixing in the chewed samples into three groups (poor, medium and good) by visual inspection. A discriminant analysis was performed using the five variables as predictors of two groups (good and poor). Mixing Ability Index (MAI) was calculated from the discriminant function and using this index, 97% of the samples from these two groups were classified correctly. This system needed only a few minutes to complete and is easy to use. Therefore, it has high potentials for clinical use.

Adult↗
PubMed2003

Validity and reliability of a newly developed method for evaluating masticatory function using discriminant analysis.

The objective of the study was to assess validity and reliability of a newly developed method for evaluating mixing ability of masticatory function. A two-coloured paraffin wax cube was used as a test food in the mixing ability test. Eleven full dentate and 33 denture wearers participated in the validity assessment. They were divided into three groups according to their dental state. Validity was assessed by the Spearman's coefficient of correlations between the mixing ability test and the sieving method used as a 'gold standard' test of the masticatory performance. The subjects were asked to masticate the test foods for 5, 7, 10, 15, 20 and 30 strokes in each test. Significant correlations (P < 0.001) were obtained in natural dentition group (r(s) = 0.66), in denture-natural dentition group (r(s) = 0.72) and in denture-denture group (r(s) = 0.56). In the reliability assessment, three full dentate subjects were asked to repeat the mixing ability test a number of times. The intraclass correlation coefficients were 0.94 in interexaminer consistency, 0.98 in intra-examiner consistency, 0.89 in test-retest consistency and 0.99 in measuring consistency. These results indicated that the mixing ability test had the validity and the reliability for evaluation of the masticatory performance.

Adult↗
PubMed2003

Influence of working side contacts on masticatory function for mandibular distal extension removable partial dentures.

The aim of this study was to clarify the influence of working side contacts for masticatory function for a distal extension removable partial denture. Five subjects who had edentulous arches from second premolar to second molar opposing natural teeth participated. Working side contacts were altered by using three types of artificial teeth attached to the denture base. A-form teeth made contact with opposite teeth while acting as the working side in a lateral excursion. The cusp angles of B- and C-form teeth were decreased by 10 degrees and 20 degrees, respectively compared with A-form teeth. B-and C-form teeth discluded with opposite teeth on the working side. Subjects were asked to perform two kinds of masticatory performance test. Obtained data were evaluated by the repeated-measures anova and the Tukey test for multiple comparisons. Results revealed that there was a significant difference (P=0.001) in the three types of teeth in the mixing ability test and the value of A-form teeth was statistically less value than those of the other teeth. However, there was no significant difference in the comminuting ability test. These results suggested that working side contacts between artificial teeth and opposite natural teeth influenced mixing ability, but not comminuting ability.

Adult↗
PubMed2003

Isolation of Mycoplasmas from nasal swabs of calves affected with respiratory diseases and antimicrobial susceptibility of their isolates.

Nasal swabs of 293 calves were examined for Mycoplasma. The samples were collected from calves affected with respiratory diseases on 71 farms in various parts of Japan between 1996 and 1997. Mycoplasma bovirhinis was isolated from 47 of 293 calves (16.0%). Mycoplasma alkalescens, M. bovis, M. arginini, M. bovigenitalium and Acholeplasma spp. were isolated from 19 (6.5%), seven (2.4%), four (1.4%), four (1.4%) and 18 (6.1%) calves, respectively. Pasteurella multocida and P. haemolytica were isolated from 60% of Mycoplasma-positive calves. However, other bacteria were not isolated from calves. To evaluate the antimicrobial susceptibility of their isolates, 68 M. bovirhinis, 21 M. alkalescens and 10 M. bovis strains were examined for 12 antimicrobial agents. All isolates showed higher susceptibility to tiamulin than to the other drugs used in the study. However, erythromycin had no effect on any of the Mycoplasma strains studied. The field isolates were less susceptible than the type strains to some drugs, such as spiramycin, oxytetracycline and tylosin.

Animals↗
PubMed2003

Feasibility study using a new small electronic pancreatoscope: description of findings in chronic pancreatitis.

BACKGROUND AND STUDY AIMS: Numerous images characteristic of chronic pancreatitis have been obtained with fiberoptic peroral pancreatoscopy systems. However, the resolution of these images is inferior to that obtained with peroral electronic pancreatoscopy (PEPS). Clearer images of the pancreatic duct with chronic pancreatitis have now been documented, in some cases using PEPS alone. The significance of this finding is reported here. PATIENTS AND METHODS: A total of 42 PEPS procedures were carried out in 36 patients with chronic pancreatitis, without sphincterotomy or balloon dilation of the papilla of Vater. Using endoscopic retrograde pancreatography, the patients were classified as having equivocal (n=5), mild (n=5), moderate (n=15), or marked (n=11) degrees of chronic pancreatitis. The insertion rate with PEPS was 90 % (38 of 42 procedures), and it was ultimately possible to examine five, three, 13, and 11 patients in each group, respectively. RESULTS: Images of turbid pancreatic juice, protein plugs of various shapes, pancreatic calculi, indistinct vascular markings, whitish mucosa, local redness, scattered redness, disappearance of the fold, deformation of the fold, irregularly dilated lumen, and stenosis were found to be characteristic of chronic pancreatitis. These images were obtained using PEPS. CONCLUSIONS: PEPS proved to be a feasible new technique for diagnosing chronic pancreatitis, and it was able to detect abnormal findings more clearly than other imaging methods.

Aged↗
PubMed2003

On the importance of early reflections for speech in rooms.

This paper presents the results of new studies based on speech intelligibility tests in simulated sound fields and analyses of impulse response measurements in rooms used for speech communication. The speech intelligibility test results confirm the importance of early reflections for achieving good conditions for speech in rooms. The addition of early reflections increased the effective signal-to-noise ratio and related speech intelligibility scores for both impaired and nonimpaired listeners. The new results also show that for common conditions where the direct sound is reduced, it is only possible to understand speech because of the presence of early reflections. Analyses of measured impulse responses in rooms intended for speech show that early reflections can increase the effective signal-to-noise ratio by up to 9 dB. A room acoustics computer model is used to demonstrate that the relative importance of early reflections can be influenced by the room acoustics design.

Adult↗
PubMed2003

Variation during the week in the incidence of acute myocardial infarction: increased risk for Japanese women on Saturdays.

BACKGROUND: Variations in the incidence of acute myocardial infarction during the week may differ between and within communities, according to lifestyle. OBJECTIVE: To identify potential triggering factors for acute myocardial infarction by examining variations in incidence in the days of the week within the Osaka area of Japan. PATIENTS: Of 2511 consecutive patients in this region who were admitted to hospital for acute myocardial infarction between April 1998 and March 2001 and consented to take part, 2400 who had a definitely identified time of onset were enrolled. RESULTS: For this group as a whole, no significant difference in incidence was noted between days of the week. However, in subgroup analyses women were shown to have significant variation through the week, peaking on Saturday with a 39% increase in relative risk (p = 0.037); working subjects showed a peak on Monday, with a 26% increase in relative risk (p = 0.038). Stratified analyses showed that in working men there was a prominent Monday peak in the onset of infarction, with a 30% increase in relative risk (p = 0.022), while in working women, there was no significant variation through the week. CONCLUSIONS: Earlier findings of a Monday peak linked to increased physical and mental occupational stress are confirmed. There is also an increase in uncertain risk factors on Saturdays for Japanese women, possibly involving a stressful weekend burden for women. Confirmation of this finding in other communities may help identify triggers of acute myocardial infarction and be useful in prevention.

Adult↗
PubMed2003

Diffuse retinochoroiditis due to Baylisascaris procyonis in Monglian gerbils.

Baylisascaris procyonis, raccoon roundworm, causes a severe retinal lesion in humans. The lesion is termed as diffuse unilateral subacute neuroretinitis (DUSN). To understand the pathogenesis of B. procyonis in gerbils, we inoculated 17 embryonated eggs/g body weight of B. procyonis into 15 male Mongolian gerbils, Merionis ungiculatus, and monitored their fundi with an ophthalmoscope. Six of 15 gerbils (40%) showed severe retinitis with a sinuous track due to larval movement. The lesions extended across nearly half of the affected fundi. Histopathological examination revealed perivasculitis in the optic disk region, inflammatory proliferation of the pigment cells, and vitreitis in most cases. These findings were similar to those in human cases of DUSN, suggesting that gerbils might be a useful model for understanding the pathogenesis of B. procyonis infection in humans.

Animals↗