Biomedical subjects

T Fujisawa

Publications and source records attributed to T Fujisawa.

At least 55 records · Page 3Linked to original sources

PubMed2002

Nonequilibrium transport through a vertical quantum dot in the absence of spin-flip energy relaxation.

We investigate nonequilibrium transport in the absence of spin-flip energy relaxation in a few-electron quantum dot artificial atom. Novel nonequilibrium tunneling processes involving high-spin states, which cannot be excited from the ground state because of spin blockade, and other processes involving more than two charge states are observed. These processes cannot be explained by orthodox Coulomb blockade theory. The absence of effective spin relaxation induces considerable fluctuation of the spin, charge, and total energy of the quantum dot. Although these features are revealed clearly by pulse excitation measurements, they are also observed in conventional dc current characteristics of quantum dots.

Journal Article↗

PubMed2002

Selective inhibition of protein kinases blocks the formation of a new axis, the beginning of budding, in Hydra.

In Hydra, head regeneration and bud formation appear to be very similar processes. The fact that there are genes whose expression is specific for one of the two processes suggests that they do not have identical molecular bases. We analyzed the signal transduction pathways regulating bud development using inhibitors of protein kinase C, Src, PI3K and ERK. The four inhibitors reversibly blocked bud formation in Hydra when applied before stage 1. Once the bud reached stage 3, three of them had no effect and the bud developed normally. The inhibitors blocked the expression of Budhead, an early head marker, and of CnOtx which are specific for bud formation. The results are in agreement with the central role of a signaling pathway mediated by Src on bud development.

Animals↗

PubMed2002

Airway epithelial cells promote transmigration of eosinophils in a new three-dimensional chemotaxis model.

BACKGROUND: Prominent infiltration of eosinophils in airway mucosa is the pathognomonic sign of asthma. The role of airway epithelial cells in eosinophil infiltration, however, has not been fully elucidated. OBJECTIVE: The aim of this study is to develop a new in vitro transmigration system composed of airway epithelial cells and extracellular matrix, and to investigate the role of airway epithelial cells in eosinophil infiltration. METHODS: A layer of type I collagen gel was formed in Netwell, and BEAS-2B bronchial epithelial cells were cultured on the gel. Then the wells covered with epithelial monolayer were filled with medium, inverted, and new upper chambers were constructed on the gel side by applying a ring cap. After further incubation with or without exogenous cytokines for 48 h, eosinophils or neutrophils were loaded in upper chambers (the gel side) and cells transmigrated to lower chambers (the epithelial cell side) were counted. Immunohistochemical analyses were also performed. RESULTS: While a simple collagen gel hardly promoted eosinophil migration even in the presence of eotaxin or RANTES, significant numbers of eosinophils migrated to lower chambers in the presence of the epithelial cells. Replacement of medium in the lower chamber (the epithelial cell side) with fresh medium, addition of exogenous eotaxin or RANTES in the upper chamber (the gel side), or pre-treatment of eosinophils with anti-CCR3 all inhibited transmigration. We found that the epithelial cells produced and deposited extracellular matrix proteins such as type IV collagen onto the type I collagen gel. Separately, we found that type IV collagen itself was capable of enhancing eotaxin-induced eosinophil migration in a standard chemotaxis assay. Neutrophils also efficiently migrated in the present transmigration system. Pre-treatment of epithelial cells with TNF-alpha and IL-4 enhanced eosinophil transmigration, while that of neutrophils was enhanced by TNF-alpha but suppressed by IL-4. CONCLUSION: By utilizing a new in vitro transmigration system mimicking the airway mucosa, we have demonstrated that airway epithelial cells play an essential role in transmigration of eosinophils and that multiple factors such as chemokines, extracellular matrix proteins and exogenous inflammatory cytokines are involved in efficient transmigration.

Bronchi↗

PubMed2002

A case of primary low grade mucosa associated lymphoid tissue (MALT) lymphoma of the oesophagus.

We report a very rare case of primary low grade mucosa associated lymphoid tissue (MALT) lymphoma of the oesophagus. An 83 year old woman was referred to our hospital in June 1999 for further examination and treatment of oesophageal tumour. Although a physical examination and laboratory data showed no significant abnormalities, endoscopic observation revealed two slightly elevated submucosal tumour-like lesions of the oesophagus. Tissue specimens were obtained by endoscopic mucosal resection of the oesophagus using a cap fitted panendoscope. The lesions were composed of diffuse small atypical lymphoid cells--that is, centrocyte-like cells--which were stained with CD20, L26, BCL-2, and kappa, but not with CD3, CD5, CD10, or cyclin D1. Monoclonality was detected by polymerase chain reaction analysis using the primer for CDR-3 of immunoglobulin H and diagnosed as low grade MALT lymphoma of the oesophagus. The tumours were considered to be completely resected and therefore additional treatment was not administered. The patient is alive and well 22 months after treatment and diagnosis.

Aged↗

PubMed2002

Subepithelial vascular patterns in bronchial dysplasias using a high magnification bronchovideoscope.

BACKGROUND: We have developed a method of high magnification bronchovideoscopy that enables improved observation of subepithelial vascular patterns of the bronchial mucosa. A study was undertaken to investigate the value of high magnification bronchovideoscopy in the detailed examination of dysplasia in the bronchial mucosa of patients with abnormal mucosal fluorescence. METHODS: Thirty one patients with sputum cytology specimens suspicious or positive for malignancy were entered into the study. Conventional white light examination was first performed under local anaesthesia and fluorescence bronchoscopy was also carried out using a light induced fluorescence endoscopy (LIFE) lung system. A high magnification bronchovideoscope (XBF 200HM2) was then used to examine the microvascular network in the bronchial mucosa at sites of normal and abnormal fluorescence and the images obtained were compared with pathological diagnoses from bronchial biopsy specimens. Vascular area ratios were calculated using image analysing apparatus. RESULTS: Vascular networks with regular patterns were observed at 20 of 22 abnormal fluorescence sites in biopsy specimens from patients with bronchitis. However, vascular networks with increased vessel growth and complex networks of tortuous vessels of various sizes were observed in 15 of 21 abnormal fluorescence sites in dysplasia specimens. There was a significant difference between bronchitis and dysplasia specimens (OR=25, 95% CI 5.5 to 113, p<0.0001). Mean vascular area ratios from 16 normal bronchial epithelium specimens with normal fluorescence, and 22 bronchitis and 21 dysplasia specimens with abnormal fluorescence were 0.054 (95% CI 0.039 to 0.07), 0.095 (95% CI 0.072 to 0.118), and 0.173 (95% CI 0.143 to 0.203), respectively. The results indicate a statistically significant increase in vascular area in the three groups (p<0.0001). CONCLUSION: Areas of increased vessel growth and complex networks of tortuous vessels in the bronchial mucosa detected using a high magnification bronchovideoscope at sites of abnormal fluorescence may enable discrimination between bronchitis and dysplasia.

Aged↗

PubMed2002

Bronchopleural fistula after lung cancer surgery. Multivariate analysis of risk factors.

BACKGROUND: To elucidate retrospectively the risk factors for bronchopleural fistulae after lung cancer surgery. METHODS: The subjects were 1,177 patients with lung cancer who underwent surgery between 1983 and 1997. Twenty-two clinical factors were examined by logistic analysis. RESULTS: Bronchopleural fistulae were observed in 35 patients (32 males, 3 females) with a mean age of 64 years. Eighteen (51%) of 35 patients died of BPF-related complications. The significant risk factors obtained by univariate analysis were male gender, heavy smoking, current smoking, low level of %FVC, metastases to lymph nodes, squamous cell carcinoma, increased WBC, decreased albumin, advanced postsurgical stage, sleeve lobectomy, and resection of the right lower lobe or middle and lower lobe. The significant risk factors noted by multivariate analysis were heavy smoking (30 or more pack/years), current rather than past smoking, metastases to lymph nodes, decreased albumin (3.5 mg/dl or less), and resection of the right lower lobe or middle and lower lobe. CONCLUSIONS: The above risk factors must be taken into account before surgical techniques followed by adequate perioperative management are selected.

Adolescent↗

PubMed2001

Characterization of genes encoding multi-domain proteins in the genome of the filamentous nitrogen-fixing Cyanobacterium anabaena sp. strain PCC 7120.

Computational analysis of gene structures in the genome of Anabaena sp. PCC 7120 revealed the presence of a large number of genes encoding proteins with multiple functional domains. This was most evident in the genes for signal transduction pathway and the related systems. Comparison of the putative amino acid sequences of the gene products with those in the Pfam database indicated that and PAS domains which may be involved in signal recognition were extremely abundant in Anabaena: 87 GAF domains in 62 ORFs and 140 PAS domains in 59 ORFs. As for the two-component signal transduction system, 73, 53, and 77 genes for simple sensory His kinases, hybrid His kinases and simple response regulators, respectively, many of which contained additional domains of diverse functions, were presumptively assigned. A total of 52 ORFs encoding putative Hanks-type Ser/Thr protein kinases with various domains such as WD-repeat, GAF and His kinase domains, as well as genes for presumptive protein phosphatases, were also identified. In addition, genes for putative transcription factors and for proteins in the cAMP signal transduction system harbored complex gene structures with multiple domains.

Bacterial Proteins↗

PubMed2001

Exhaled nitric oxide decreases during exercise-induced bronchoconstriction in children with asthma.

Nitric oxide (NO) produced in the airways can be either detrimental or protective to the host. To investigate the role of NO in the pathogenesis of exercise-induced bronchoconstriction (EIB), we measured exhaled NO (ENO) after exercise challenge in 39 asthmatic and six normal children. FEV(1) and ENO were measured before and at 0, 5, 10, and 15 min after exercise performed on a treadmill for 6 min. EIB was defined as a decrease in FEV(1) of more than 15% after the exercise. Normal children (control group) did not have EIB. Twenty-one patients with asthma had EIB (EIB group) whereas the remaining 18 patients did not (non-EIB group). The baseline ENO value was significantly higher in the asthmatic children than in the normal children, and there was a positive correlation between the maximal percent decrease in FEV(1) and the baseline ENO value (r = 0.501, p = 0.012). At the end of the exercise, ENO had decreased in all the subjects. In the non-EIB and control groups, ENO rebounded to above the baseline at 5 min after the exercise and thereafter. In contrast, ENO remained at a decreased level in the EIB group. The change in ENO did not correlate with the change in minute ventilation, and beta-agonist inhalation at the peak of EIB that accelerated the recovery of FEV(1) did not affect the depressed level of ENO, demonstrating that the reduction of ENO is not a simple consequence of increased ventilation nor airway obstruction. Among the EIB group, steroid-treated patients showed sooner recovery in ENO after the exercise than steroid-naive patients. Our study suggests that NO production in response to exercise may be impaired in patients with EIB, and that ENO represents not only airway inflammation but also a protective function of NO in EIB.

Administration, Inhalation↗

PubMed2001

Apoptosis and proliferative activity in mature and immature teratomas of the mediastinum.

BACKGROUND: Mediastinal teratomas are the most frequent mediastinal germ cell tumor. Whereas mature teratomas are benign tumors, immature teratomas are malignant. The purpose of this study was to find characteristics that could be used to distinguish between the growth and prognosis of the two teratoma types. METHODS: Twenty-four mediastinal teratomas (18 mature and 6 immature) were examined for apoptosis by 3'-end labeling of DNA and stained immunohistochemically for proliferating cell nuclear antigen, Bcl-2, Bax, p53 protein, and alpha-fetoprotein (AFP) expression in formalin fixed, paraffin embedded specimens. RESULTS: AFP was expressed in both immature teratomas and mature teratomas. Whereas p53 protein was expressed by most teratomas, p53 gene mutation was observed in only one patient with an immature teratoma in which the same mutation occurred in all tumor tissue components tested. Bax protein expression was relatively diffuse in mature teratomas but was focally expressed in immature teratomas. Bcl-2 protein was expressed focally in both mature and immature teratomas. Although the proliferative index was significantly higher in immature teratomas compared with mature teratomas (P < 0.001), the apoptotic index (AI) was significantly higher in mature teratomas compared with immature teratomas (P < 0.05). All patients except one in this study remain alive and disease free after undergoing tumor resection. CONCLUSIONS: The relatively high AI in mature teratomas may be due to the overexpression of the p53 protein. In contrast, immature teratomas exhibited higher proliferative activity and lower rates of apoptosis, which may explain the more aggressive behavior of these tumors. However, patients with immature mediastinal teratomas have a good prognosis if the tumor is resected completely after chemotherapy.

Adolescent↗

PubMed2001

Adjuvant chemotherapy for large cell carcinoma with neuroendocrine features.

BACKGROUND: In 1999, the World Health Organization categorized large cell neuroendocrine carcinoma, large cell carcinoma with neuroendocrine differentiation, and large cell carcinoma with neuroendocrine morphology as a variant of large cell carcinoma. Patients with large cell carcinoma with neuroendocrine features have poor prognoses, comparable to those for small cell lung carcinoma. Small cell lung carcinoma is sensitive to chemotherapy; however, it is still unclear whether large cell carcinoma with neuroendocrine features is responsive to adjuvant chemotherapy. METHODS: The authors analyzed 73 patients with large cell carcinoma with neuroendocrine features who underwent resection of the tumor and studied the effect of adjuvant chemotherapy for large cell carcinoma with neuroendocrine features. RESULTS: In patients with Stage I disease, the overall survival for patients with adjuvant chemotherapy based on cisplatin, carboplatin, or cyclophosphamide, which were used as standard chemotherapy for small cell lung carcinoma, were significantly higher than the overall survival for patients without adjuvant chemotherapy. In patients with Stage II, III, and IV disease, there was no significant difference between patients with adjuvant chemotherapy and without adjuvant chemotherapy. CONCLUSIONS: Adjuvant chemotherapy based on cisplatin, carboplatin, or cyclophosphamide prolongs survival of patients with large cell carcinoma with neuroendocrine features in early stage.

Adult↗

PubMed2001

Increased telomerase activity and elevated hTERT mRNA expression during multistage carcinogenesis of squamous cell carcinoma of the lung.

BACKGROUND: Telomerase activation is believed to play a critical role in the immortalization of cells and carcinogenesis. Telomerase activity is undetectable in normal somatic cells (except for those cells undergoing proliferation) but is expressed in the majority of human tumors including lung carcinoma. The expression of hTERT mRNA has been found to be correlated with telomerase activity. In the current study, the authors analyzed telomerase activity and hTERT mRNA expression in preinvasive bronchial lesions using biopsy specimens obtained by fluorescence bronchoscopy. METHODS: The authors studied 150 bronchial biopsy specimens obtained by fluorescence bronchoscopy. The intensity of telomerase activity was determined by the fluorescence-based telomeric repeat amplification protocol method in 74 bronchial biopsy specimens (22 normal bronchial epithelium or bronchitis cases, 15 squamous metaplasia cases, 23 dysplasia cases, and 14 squamous cell carcinoma cases), and the level of hTERT mRNA was analyzed in another 76 specimens (24 normal bronchial epithelium or bronchitis cases, 15 squamous metaplasia cases, 20 dysplasia cases, and 17 squamous cell carcinoma cases) by real-time polymerase chain reaction. RESULTS: The mean values (+/- the standard deviation [SD]) of telomerase activity in normal bronchial epithelium or bronchitis, squamous metaplasia, dysplasia, and squamous cell carcinoma cases were 6.2 +/- 7.5, 13.9 +/- 14.8, 18.5 +/- 20.8, and 54.5 +/- 22.3 U/microg protein, respectively. The upper limit of telomerase activity in normal bronchial epithelium or bronchitis was 21 U/microg protein (mean + 2SD). It is interesting to note that, 5 of 15 squamous metaplasia biopsies (33%), 8 of 23 dysplasia biopsies (35%), and all squamous cell carcinoma biopsies (100%) exhibited levels of telomerase activity that were > 21 U/microg protein. The mean levels of hTERT mRNA in normal bronchial epithelium or bronchitis, squamous metaplasia, dysplasia, and squamous cell carcinoma cases were 891 +/- 840, 1936 +/- 1704, 3019 +/- 2607, and 12965 +/- 18008 copies/microg total RNA, respectively. Telomerase activity and hTERT mRNA expression were found to increase in proportion to the severity of histologic change from normal bronchial epithelium or bronchitis to squamous cell carcinoma. CONCLUSIONS: These results suggest that an increase in telomerase activity and hTERT mRNA expression are features of the early stages of the development of squamous cell carcinoma of the lung, with strong telomerase activity and hTERT mRNA expression being prominent during the latter stages.

Adult↗

PubMed2001

Clinical characterization of pulmonary large cell neuroendocrine carcinoma and large cell carcinoma with neuroendocrine morphology.

BACKGROUND: Large cell carcinoma has been classified as four potential types based on its neuroendocrine morphology and evidence of neuroendocrine differentiation discernible by immunohistochemistry or electron microscopy. However, the clinical relation among these four categories has not been clearly defined. In 1999, the World Health Organization (WHO) categorized large cell neuroendocrine carcinoma as a variant of large cell carcinoma. MATERIAL AND METHODS The authors analyzed 119 cases of large cell carcinoma from a total of 2070 primary lung carcinoma cases resected surgically between 1969-1999. Using light microscopy, electron microscopy, and immunohistochemical staining, the authors reclassified these cases into large cell neuroendocrine carcinoma (LCNEC), large cell carcinoma with neuroendocrine differentiation (LCCND), large cell carcinoma with neuroendocrine morphology (LCCNM), and classic large cell carcinoma (CLCC). RESULTS: In multivariate analyses, the authors found that large cell carcinoma with neuroendocrine features, which combined LCNEC, LCCND, and LCCNM, impacted both the overall survival and disease-free survival of patients. The clinical behavior of LCCNM was similar to that of LCNEC. CONCLUSIONS: Large cell carcinomas with neuroendocrine features appear to be more clinically aggressive than CLCCs. The authors' findings suggest that the histologic identification of neuroendocrine features in tumor tissue from patients diagnosed with large cell carcinoma of the lung may have clinical relevance.

Adult↗

PubMed2001

The shapes and sizes of two domains of tropomodulin, the P-end-capping protein of actin-tropomyosin.

Tropomodulin, the P-end (slow-growing end)-capping protein of the actin-tropomyosin filament, and its fragment (C20) of the C-terminal half were studied by synchrotron small-angle X-ray scattering, restoring low-resolution shapes using an ab initio shape-determining procedure. Tropomodulin is elongated (115 A long) and consists of two domains, one of 65 A in length and the other being similar to C20 in shape and size if the long axes of the two are tilted by about 40 degrees relative to each other. We propose a model for tropomodulin in association with tropomyosin and actin: the N-terminal half of tropomodulin, a rod, binds to the N-terminus of tropomyosin and the C-terminal triangle domain protrudes from the P-end being slightly bent towards the actin subunit at the end, thereby blocking the P-end.

Actin Depolymerizing Factors↗

PubMed2001

Large-scale domain movements and hydration structure changes in the active-site cleft of unligated glutamate dehydrogenase from Thermococcus profundus studied by cryogenic X-ray crystal structure analysis and small-angle X-ray scattering.

Here we describe the large-scale domain movements and hydration structure changes in the active-site cleft of unligated glutamate dehydrogenase. Glutamate dehydrogenase from Thermococcus profundus is composed of six identical subunits of M(r) 46K, each with two distinct domains of roughly equal size separated by a large active-site cleft. The enzyme in the unligated state was crystallized so that one hexamer occupied a crystallographic asymmetric unit, and the crystal structure of the hexamer was solved and refined at a resolution of 2.25 A with a crystallographic R-factor of 0.190. In that structure, the six subunits displayed significant conformational variations with respect to the orientations of the two domains. The variation was most likely explained as a hinge-bending motion caused by small changes in the main chain torsion angle of the residue composing a loop connecting the two domains. Small-angle X-ray scattering profiles both at 293 and 338 K suggested that the apparent molecular size of the hexamer was slightly larger in solution than in the crystalline state. These results led us to the conclusion that (i) the spontaneous domain motion was the property of the enzyme in solution, (ii) the domain motion was trapped in the crystallization process through different modes of crystal contacts, and (iii) the magnitude of the motion in solution was greater than that observed in the crystal structure. The present cryogenic diffraction experiment enabled us to identify 1931 hydration water molecules around the hexamer. The hydration structures around the subunits exhibited significant changes in accord with the degree of the domain movement. In particular, the hydration water molecules in the active-site cleft were rearranged markedly through migrations between specific hydration sites in coupling strongly with the domain movement. We discussed the cooperative dynamics between the domain motion and the hydration structure changes in the active site of the enzyme. The present study provides the first example of a visualized hydration structure varying transiently with the dynamic movements of enzymes and may form a new concept of the dynamics of multidomain enzymes in solution.

Binding Sites↗

PubMed2001

X-ray diffraction evidence for the lack of stereospecific protein interactions in highly activated actomyosin complex.

The structure of actomyosin complex while hydrolyzing ATP was investigated by recording X-ray diffraction patterns from rabbit skeletal muscle fibers, in which exogenously introduced rabbit skeletal subfragment-1 (S1) was covalently cross-linked to the endogenous actin filaments in rigor by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC). Approximately two-thirds of the introduced S1 was cross-linked. The cross-linking procedure did not affect the profile of the S1-induced enhancement of the actin-based layer line reflections in rigor, indicating that the acto-S1 interactions remained highly stereospecific. In the presence of ATP, the MgATPase of the S1 was highly activated regardless of calcium levels, presumably because the availability of the stereospecific binding sites for both proteins was maximized by the cross-linking. However, the diffraction pattern in the presence of ATP was striking in that the intensity profile of the strong 1/5.9 nm(-1) layer lines was indistinguishable from that from bare actin filaments, despite the fact that the majority of the S1 was still associated with actin. The change of the intensity profiles upon addition of ATP was completely reversible. Model calculations showed that this result can be explained if the S1 is not only swinging around its pivoting point, but the pivoting point itself is also moving on the actin surface in a range of a few nanometers. The results suggest that the stereospecific binding sites, which have been considered important for actomyosin cycling, are paradoxically left unoccupied for most of the time in this highly activated actomyosin complex.

Actins↗

PubMed2001

Change in cellular localization of a rheumatoid arthritis-related antigen (RA-A47) with downregulation upon stimulation by inflammatory cytokines in chondrocytes.

We previously isolated a rheumatoid arthritis-related antigen (RA-A47) protein that had reactivity with RA sera from a human chondrosarcoma-derived chondrocytic cell line, HCS-2/8. Sequencing analysis of ra-a47 cDNA revealed RA-A47 as a product of the colligin-2 gene, which is also known as the human heat shock protein (HSP) 47 gene. Expression of hsp47 has been shown to be cooperatively altered with that of collagen genes upon stimulation. In this study, it was confirmed that the mRNA expression of ra-a47 and COL2A1, a type II collagen gene, was upregulated on stimulation with transforming growth factor (TGF) beta in chondrocytes. However, in contrast, inflammatory cytokines such as tumor necrosis factor (TNF) alpha, interferon (IFN) beta, and interleukin (IL)-6 downregulated the expression of ra-a47 mRNA, whereas the expression of COL2A1 mRNA was not repressed, or even upregulated, in HCS-2/8 cells. Of note, inducible NO synthase (iNOS) and matrix metalloproteinase (MMP)-9 mRNAs were strongly stimulated by TNFalpha. We also found that cell-surface type II collagen disappeared upon such a stimulation, suggesting that decrement of RA-A47 may inhibit the secretion of type II collagen and lead to its accumulation inside the cells. RA-A47 was detected in the cultured medium of TNFalpha-treated HCS-2/8 cells and of IL-1-treated rabbit chondrocytes by Western blot analysis. Under the same conditions, RA-A47 was detected on the cell surface by immunofluorescence staining. These findings demonstrate that the RA-A47 chaperone protein is specifically downregulated, causing the intracellular accumulation of unsecretable type II collagen, while the extracellular matrix (ECM) is degraded by MMPs and iNOS through the stimulation of chondrocytes by TNFalpha. The altered localization of RA-A47 to the surface or outside of cells may represent the mechanism for the recognition of RA-A47 as an autoantigen during rheumatoid arthritis.

Animals↗

PubMed2001

Polyps, peptides and patterning.

Peptides serve as important signalling molecules in development and differentiation in the simple metazoan Hydra. A systematic approach (The Hydra Peptide Project) has revealed that Hydra contains several hundreds of peptide signalling molecules, some of which are neuropeptides and others emanate from epithelial cells. These peptides control biological processes as diverse as muscle contraction, neuron differentiation, and the positional value gradient. Signal peptides cause changes in cell behaviour by controlling target genes such as matrix metalloproteases. The abundance of peptides in Hydra raises the question of whether, in early metazoan evolution, cell-cell communication was based mainly on these small molecules rather than on the growth-factor-like cytokines that control differentiation and development in higher animals.

Amino Acid Sequence↗

PubMed2001

Evaluation of urinary rapid test for Helicobacter pylori in general practice.

There is increasing interest in noninvasive tests for the diagnosis of Helicobacter pylori (H. pylori) infection. One such test, a urine-based rapid test kit (RAPIRUN H. pylori Antibody, Otsuka Pharmaceutical Co., Ltd.) for detection of antibody to H. pylori, has been developed and is considered ideal. In addition to its noninvasiveness and safe handling-due to use of urine as a sample-the assay procedure used for the urinary rapid test is very simple. Only 10-20 minutes are required to complete an assay, and no instruments are needed. The aim of this study was to examine the clinical usefulness of this urine-based rapid test. A total of 189 patients, including 76 patients with gastroduodenal disease, were recruited. A pair of random single-void urine and serum samples was collected from each of the 189 patients, and antibody to H. pylori in the urine and serum samples was measured using the urine-based rapid test kit and three commercially available serum-based ELISA kits. For the patients with gastroduodenal disease, invasive diagnostic methods using endoscopic biopsy specimens such as culture, histology, and rapid urease test were also performed. The sensitivity, specificity, and accuracy of the urinary rapid test were evaluated on the basis of the three serum ELISA results or the invasive diagnostic results. In addition, various urinalyses were performed, and the effects of substances existing in urine on the urinary rapid test results were examined. Of the 189 patients, the urinary rapid test was positive for 110 (58.2%), negative for 78 (41.3%), and invalid for only one patient (0.5%). Based on the three serum-based ELISA results, the sensitivity, specificity, and accuracy of the urinary rapid test were 93.7, 88.9, and 92.2%, respectively. On the basis of the biopsy-based test results, the sensitivity of the urinary rapid test was 100% and its accuracy (95.2%) was equivalent or superior to that of each serum-based ELISA. In addition, no significant differences were observed between groups positive and negative on urinary rapid testing in any urinalysis parameter examined. The novel urinary rapid test kit evaluated in this study enables simple, rapid, and accurate diagnosis of H. pylori infection, and is an ideal test method for point-of-care testing.

Adult↗