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Biomedical subjects

J Suzuki

Publications and source records attributed to J Suzuki.

At least 235 records · Page 13Linked to original sources
PubMed1997

Signal analysis and compression performance evaluation of pathological microscopic images.

Digitizing high-quality microscopic images and developing input/output technology for displaying those results is critical to telepathology in which pathological microscopic images are transferred to remote locations where they are diagnosed by specialists. This paper will discuss the results achieved by directly digitizing (nonfilm process) pathological microscopic images at a 2k x 2k resolution, and then using a super-high-definition imaging system to analyze their signals and evaluate compression performance. We will start off by digitizing samples that a pathologist will actually use in making a diagnosis, and then analyze their color distribution and spatial frequencies characteristics by comparing them to general images. This will make it apparent that such pathological images characteristically contain high spatial frequency in their chrominance components. We will also discuss the evaluation results of color differences for L*a*b* space and compression ratios achieved when using JPEG to encode pathological images. We will also present a subjective evaluation of the influence subsampling of chrominance components has on image quality.

Computer Systems↗
PubMed1997

Contrast mapping and evaluation for electronic X-ray images on CRT display monitor.

Simple chest X rays on film are the most common type of image in medical diagnosis. However, amongst the various types of medical X-ray images, they require the highest level of display quality due to the fact that the body structures they capture on film have varying degrees of permeability to X rays. Conventional high-definition digital display technology has not always been able to match the quality of such film images. This has been a major impediment against progress toward the complete digitization of simple chest X rays. The intent of this paper is to examine that, when applied to medical diagnosis of chest X rays, super-high-definition (SHD) images (digital images with resolution exceeding that of HDTV) are capable of producing a level of quality of diagnostic accuracy on a par with conventional film images. We will start out by seeking out the overall transmission characteristics of a system that uses digital radiography and a film digitizer to digitize images. We will then derive gray-scale transform characteristics based on the luminance linear method for approximating, as closely as possible on a CRT, film images on a light box that have wide dynamic range and high luminance. Finally, we will present the results of image evaluation experiments using high-definition CRT monitors. These results indicate that conventional film images and those on super-high-definition CRT monitors have nearly the same quality. They will also show that the contrast mapping selected by radiologists and theoretical luminance linear characteristics were almost the same except in low-luminance regions. We will also discuss radiologists' comments on CRT monitors after they participated in the evaluation experiment.

Data Display↗
PubMed1997

A long-term survey of methicillin-resistant Staphylococcus aureus in the oral cavity of children.

Methicillin-resistant Staphylococcus aureus (MRSA), an indigenous bacteria in healthy people, often causes nosocomial infections. If the host human becomes compromised, MRSA can cause a serious infection. The long-term colonization of MRSA increases this risk. The purpose of this study was to demonstrate the incidence of S. aureus and MRSA colonization in the oral cavities of healthy children, and to examine the stability of identical strains of MRSA over a long-term period. Fourteen children were examined in two stages (first stage: 1987-88, second stage: 1992-93). Five of the 14 children were negative for S. aureus in both stages, seven children were positive in both stages and two children were positive in only the second stage. The children who were colonized with S. aureus in the first stage always harbored the bacteria in the second stage. Of the seven children that were positive for S. aureus in both stages, three persisted in carrying MRSA. We compared two MRSA strains isolated from the same children in both stages by coagulase typing, antibiogram typing and DNA fingerprinting. In two children, the strains showed the same coagulase types, similar antibiograms and similar DNA fragment profiles. These data strongly suggest that identical strains of MRSA persisted in the oral cavities for more than five years, and that the oral cavity can serve as a reservoir for MRSA with the potential to cause nosocomial infections.

Carrier State↗
PubMed1997

Kidney transplantation and liaison psychiatry, part I: anxiety before, and the prevalence rate of psychiatric disorders before and after, transplantation.

We examined psychiatric problems before and after kidney transplantation in a sample of 36 patients with end-stage renal failure. The prevalence rate of psychiatric disorders was 11.1% (4 of 36 cases) before the transplantation and 36.1% (13 of 36 cases) within 2 months after the transplantation. Except for a patient with schizophrenic disorder, no patients were found to have a psychiatric disorder from 2 to 6 months after the transplantation. In this study, we also examined anxieties and/or conflicts related to the transplantation using the synthetic house-tree-person (HTP) drawing test, a measure of mood states by means of a non-verbal expression method. The upper part of the tree trunk was not drawn in 25% of this sample (5 of 20 cases). In the HTP drawing tests immediately after the transplantation, however, trees missing the upper part of trunk were not drawn. Based on these findings, we discussed psychiatric problems in kidney transplantation.

Adolescent↗
PubMed1997

Kidney transplantation and liaison psychiatry, part II: A case of dissociative identity disorder.

The authors examined the case of an adolescent patient with dissociative identity disorder secondary to psychological shock of a transplant rejection response. Psychiatric symptoms consisted of three components: visual hallucinations and delusions as a psychological defense against the anxiety of a transplant rejection; appearance of three personalities including proper self, the dead child (donor), and a prophet with strong predicting power; and a twilight state. These psychiatric symptoms may have been related to two psychological factors: immature personality characteristics formed during hemodialysis, and post-traumatic stress caused by a chronic rejection reaction from the patient's first transplant.

Adolescent↗
PubMed1997

[Properties of extracellular products produced by group A streptococci isolated from patients with streptococcal toxic shock syndrome].

Extracellular products of group A streptococci isolated from patients with streptococcal toxic shock syndrome (STSS) were examined. The outline of the discussion of the 3 products are as follows; streptolysin O (SLO), proteinase and erythrogenic toxin. SLO and proteinase showed a relatively large amount of products more than erythrogenic toxin. SLO produced by group A streptococci isolated from the patient with STSS had an isoelectric point (pI) of 6.0 and a molecular weight of 64,000 and showed hemolytic activity in the presence of 2-mercaptoethanol (2-ME). Furthermore, the hemolytic activities of all components were inhibited by gamma-globulin and cholesterol. Proteinase had pIs of 8.7 and 8.9, and a molecular weight of 21,000. These data suggest that STSS clinical criteria probably reflects a characteristic of a large amount of products of individual S. pyogenes isolates.

Bacterial Proteins↗
PubMed1997

[Urease-negative Helicobacter pylori isolates from gastrointestinal mucosa of patients with peptic ulcer].

It is well known that Helicobacter pylori produced a large amount of urease which plays an important role in the maintenance of infection and adhesion. Two thousand three hundred and thirty-one specimens of the gastrointestinal mucosa were obtained from patients with peptic ulcer to isolate H. pylori strains. Of these specimens, 1602 strains of H. pylori were isolated and 7 urease-negative H. pylori strains were found. Biological characteristics (except urease production) of urease-negative H. pylori were in accord with urease-positive reference strains (ATCC strains). Furthermore, these urease-negative strains were confirmed to be H. pylori strains by PCR. These results suggest that the emergence of urease-negative strains pose a new problem for H. pylori infection in patients with peptic ulcer.

Gastric Mucosa↗
PubMed1997

[Properties of extracellular products produced by group A streptococci isolated from patient with streptococcal toxic shock syndrome].

Extracellular products of group A streptococci isolated from patients with streptococcal toxic shock syndrome (STSS) examined. The outline of discussion of the 4 products are as follows; Products were streptolysin O (SLO), proteinase, erythrogenic toxin and DNase. SLO showed a large amount of products more than proteinase, erythrogenic toxin and DNase. It should not be concluded that there is a large amount of SLO in the isolated strains from patients with STSS. SLO produced by group A streptococci isolated from the patient with STSS has an isoelectric point (pI) of 6.0 and a molecular weight of 64,000 and shows a hemolytic activity in the presence of 2 mercaptoethanol (2-ME). Furthermore, the hemolytic activities of all components were inhibited by gamma-globulin and cholesterol. These results indicated that all component with hemolytic activity are SLO. These data suggest that STSS does not make up a single syndrome but, rather, that the multiple STSS clinical criteria probably reflects a different characteristic of individual S. pyogenes isolates.

Bacterial Proteins↗
PubMed1997

Cloning and characterization of the fmt gene which affects the methicillin resistance level and autolysis in the presence of triton X-100 in methicillin-resistant Staphylococcus aureus.

In methicillin-resistant Staphylococcus aureus (MRSA) strains, Triton X-100 reduced the oxacillin resistance level, although the degree of reduction varied from strain to strain. To study the responses of MRSA strains to Triton X-100, we isolated a Tn551 insertion mutant of the COL strain that became more susceptible to oxacillin in the presence of 0.02% Triton X-100. The Tn551 insertion of the mutant was transduced back to the parent strain, other MRSA strains (strains KSA8 and NCTC 10443), and methicillin-susceptible strain RN450. All transductants of MRSA strains had reduced levels of resistance to oxacillin in the presence of 0.02% Triton X-100, while those of RN450 did not. Tn551 mutants of KSA8 and NCTC 10443 also had reduced levels of resistance in the absence of 0.02% Triton X-100. The autolysis rates of the transductants in the presence of 0.02% Triton X-100 were significantly increased. Amino acid analysis of peptidoglycan and testing of heat-inactivated cells for their susceptibilities to several bacteriolytic enzymes showed that there were no significant differences between the parents and the respective Tn551 mutants. The Tn551 insertion site mapped at a location different from the previously identified fem and llm sites. Cloning and sequencing showed that Tn551 had inserted at the C-terminal region of a novel gene designated fmt. The putative Fmt protein showed a hydropathy pattern similar to that of S. aureus penicillin-binding proteins and contained two of the three conserved motifs shared by penicillin-binding proteins and beta-lactamases, suggesting that fmt may be involved in cell wall synthesis.

Bacteriolysis↗
PubMed1997

Experimental IgA nephropathy induced by coxsackie B4 virus in mice.

Viruses have been suspected to be etiological agents of IgA nephropathy. Recently, viruses were detected in renal tissues from patients with IgA nephropathy. We tried to cause lesions similar to IgA nephropathy by inoculating virus into mice and to detect virus RNA in the lesion by in situ hybridization. A group of mice were inoculated intravenously with coxsackie B4 virus once a month from 1 to 5 months of age and sacrificed monthly from 6 to 12 months of age. Mesangial proliferation and deposits that stained positive with periodic acid-Schiff in light microscopy and electron-dense deposits in electron microscopy were found from 6 months of age. Positive findings for IgG and IgA deposition in the mesangium were noted and the intensity of IgA deposition was predominant after 10 months of age. The signals of coxsackie B4 virus by in situ hybridization were observed in the lesions. These observations indicate that coxsackie B4 virus inoculated repeatedly into mice induces lesions similar to IgA nephropathy. The depositions of the lesions may be immune complexes of coxsackie B4 virus and these immune complexes injure renal tissues.

Animals↗
PubMed1997

Effect of sairei-to on prostaglandin E2-induced phosphatidylinositol breakdown in aminonucleoside nephrotic rat.

We describe the effects of Sairei-to, a Chinese herbal medicine, on aminonucleoside-induced nephrotic rats (ANNR), and analyze the urinary excretion of protein and phosphatidylinositol (PI) turnover via prostaglandin E2 (PGE2) receptors in isolated glomeruli. Sairei-to suppressed urinary excretion of protein and PGE2 in ANNR, and inhibited acceleration of PI turnover in isolated nephrotic glomeruli. The affected responsiveness of the PI turnover system to PGE2 in a nephrotic state was presumed to be normalized by Sairei-to. These findings suggest that Sairei-to restores abnormal changes in the PI turnover system in ANNR kidneys, and thereby inhibit excretion of protein into the urine.

Animals↗
PubMed1997

Experimental glomerulonephritis following successive inoculation of five different serotypes of group B coxsackieviruses in mice.

The purpose of the present investigation is to study renal injury by monthly viral inoculation into mice, using several different types of strains of enterovirus. A group of mice were inoculated intravenously with five different serotypes of group B coxsackieviruses (CB1 to CB5), once a month from 1 to 5 months of age and sacrificed monthly from 6 to 12 months of age. Mesangial proliferation and PAS-positive mesangial deposits in light microscopy and electron-dense deposits in electron microscopy were observed at maximum from 6 to 7 months of age. The CB viral RNA detected by in situ hybridization were observed in the mesangial lesion. By immunofluorescence findings, positive findings for IgG and IgA were observed. These results demonstrated that intermittent intravenous inoculation with different serotypes CB in mice provoked pathological changes closely resembling those in human proliferative glomerulonephritis. Moreover, the detection of CB viral RNA in glomerular lesions suggested that renal injury was induced by immune complexes correlated with CB viral replication in renal tissues.

Animals↗
PubMed1997

Changes in platelet calcium concentration by thromboxane A2 stimulation in patients with nephrotic syndrome of childhood.

In order to examine the intracellular thromboxane A2 (TXA2) signal transduction system in platelets of patients with nephrotic syndrome, we measured the levels of TXA2 metabolites in urine and blood and platelet calcium ion level as a result of STA2, an analog of STA2 (9,11-dimethylmethano-11,12-methano-TXA2) stimulation, and obtained the following results: (1) In pediatric patients with nephrotic syndrome, urinary thromboxane B2 (TXB2) and 11-dehydro-TXB2 excretion were signficantly higher in the onset and relapse groups compared to the remission and control groups. (2) The blood 11-dehydro-TXB2 level in the onset group was significantly higher than those in the remission and control groups. (3) Platelet calcium concentrations due to STA2 stimulation were significantly increased in the onset, relapse and remission groups compared to the control group. These findings suggest activation of the TXA2 signal transduction system in platelets of pediatric patients with nephrotic syndrome.

Blood Platelets↗
PubMed1997

Eosinophils as a source of matrix metalloproteinase-9 in asthmatic airway inflammation.

Bronchial asthma is characterized by eosinophil infiltration and tissue remodeling. Matrix metalloproteinases (MMPs) are thought to play critical roles by degradating interstitial matrices in a wide range of lung diseases associated with reorganization of the airway architecture. To investigate whether MMPs are involved in the pathologic processes of bronchial asthma, we examined MMP expression in asthmatic subjects. In situ hybridization revealed abundant expression of MMP-9 (gelatinase B) mRNA in biopsy specimens from asthmatic subjects (n = 5), with an average positive cell distribution of 117.8 +/- 41.1 (mean +/- SEM)/mm2. In contrast, sparse expression of the mRNA (10.8 +/- 4.8 /mm2) was observed in specimens from normal subjects (n = 4). The vast majority of cells expressing the mRNA were eosinophils in asthmatic tissues (92.2 +/- 1.2%). MMP-9 protein, which was confined to the submucosal cells in the normal subjects, was not abundantly expressed in inflammatory cells, but there was positive reactivity for MMP-9 protein in the extracellular matrix. Immunoelectron microscopic analysis showed sparse immunolocalization of MMP-9 in the perinuclear spaces of eosinophils, but not in the granules. These findings suggest the overexpression of MMP-9 by eosinophils in bronchial tissues of asthmatic individuals, and the participation of MMPs in the pathologic changes in asthmatic airways.

Adult↗
PubMed1997

Three novel mutations and a de novo deletion mutation of the DAX-1 gene in patients with X-linked adrenal hypoplasia congenita.

The DAX-1 [DSS (dosage sensitive sex)-AHC critical region on the X, gene 1] gene is responsible for X-linked adrenal hypoplasia congenita (AHC). However, DAX-1 protein structure-function relationships are not well understood. Identification of missense mutations may help to reveal these relationships. We analyzed the DAX-1 gene from seven patients in six kindreds with X-linked AHC and identified one frameshift mutation, two missense mutations, and three deletion mutations. Case 1 had a 388delAG frameshift mutation, inducing a premature stop codon at position 70. Case 2 had a missense mutation, Lys382Asn, which encodes an asparagine (Asn) for lysine (Lys) at position 382. Sibling cases of 3-1 and 3-2 had a missense mutation of Trp291 Cys, which encodes a substitution of cysteine (Cys) for tryptophan (Try) at position 291. The tryptophan (Trp) at position 291 and lysine (Lys) at position 382 in human DAX-1 protein are highly conserved among other related orphan nuclear receptor superfamily members. Cases 4, 5, and 6 showed deletion mutation. In case 6, a de novo deletion mutation was revealed by both southern hybridization and polymerase chain reaction (PCR) of a GGAA tetranucleotide tandem repeat. These findings suggest that: 1) Trp at position 291 and Lys at position 382, located in the C-terminal presumptive ligand binding domain, are important to the functional role of the DAX-1 protein in adrenal embryogenesis and/or in hypothalamic-pituitary activity; and 2) molecular analysis of the DAX-1 gene may help genetic counseling, even in cases with deletion mutation, because a detection of de novo deletion may exclude another affected or carrier child.

Adrenal Insufficiency↗
PubMed1997

Assessment of beta 2- and beta 3-adrenoceptors in rat white adipose tissues by radioligand binding assay.

We investigated the characteristics of beta-adrenoceptors (beta-ARs) in rat white adipose tissues (WAT) with a radioligand receptor binding assay using (-)-[3H]-CGP12177. Scatchard analysis revealed that there are high- and low-affinity sites for (-)-[3H]-CGP12177 in WAT. The (-)-[3H]-CGP12177 bound to a high-affinity site was displaced by 1 microM propranolol. The rank of pKi values of catecholamines for the site was isoproterenol > epinephrine > norepinephrine. By contrast, BRL37344A, BRL35135A and SR59230A, beta 3-selective agonists had high affinity for the low-affinity site of (-)-[3H]-CGP12177, whereas (-)-[3H]-CGP12177 bound to a low-affinity site was completely displaced by 100 microM bupranolol but not 1 microM propranolol. The pKi values of the catecholamines (isoproterenol, norepinephrine, epinephrine) for this site were very low. In addition, the correlation between the pKi values of various beta-agonists for the low-affinity site of rat WAT and those obtained from rat cloned beta 3-ARs was significant, but those of human cloned beta 3-ARs were not. Consequently, the results suggested that the high- and low-affinity sites were beta 2-ARs and beta 3-ARs in rat WAT, respectively.

Adipose Tissue↗
PubMed1997

Arthritis and meningitis--the first manifestations of bacterial endocarditis in 2 patients.

We have encountered 2 patients in whom the first manifestations of bacterial endocarditis were arthritis (in 1 case septic arthritis and in the other nonseptic arthritis) and bacterial meningitis. These presentations were followed by acute heart failure due to aortic valve destruction, although the patients showed no significant cardiovascular manifestations on admission. Aortic valve replacement was performed in each case and the patients' postoperative course was comfortable. We would like to emphasize the following points. (1) Arthritis and meningitis are uncommon in patients with bacterial endocarditis. However, it is necessary to consider the possibility of bacterial endocarditis when these clinical manifestations present together. Such a combination can cause rapid valve destruction. When more than 2 rare complications of bacterial endocarditis coexist, surgery should be considered as soon as the definite diagnosis of bacterial endocarditis is established, even if congestive heart failure has not yet developed. (2) Arthritis associated with bacterial endocarditis might be truly septic rather than mediated by circulating immune complexes as is commonly believed.

Aged↗