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Biomedical subjects

T Tanahashi

Publications and source records attributed to T Tanahashi.

At least 37 records · Page 2Linked to original sources
PubMed1999

Role of gamma interferon in Helicobacter pylori-induced gastric inflammatory responses in a mouse model.

The immune responses to Helicobacter pylori infection play important roles in gastroduodenal diseases. The contribution of gamma interferon (IFN-gamma) to the immune responses, especially to the induction of gastric inflammation and to protection from H. pylori infection, was investigated with IFN-gamma gene knockout (IFN-gamma-/-) mice. We first examined the colonizing abilities of eight H. pylori strains with a short-term infection test in order to select H. pylori strains which could colonize the mouse stomach. Only three strains (ATCC 43504, CPY2052, and HPK127) colonized C57BL/6 wild-type mice, although all of the strains except for ATCC 51110 could colonize IFN-gamma-/- mice. The number of H. pylori organisms colonizing the stomach in wild-type mice was lower than that in IFN-gamma-/- mice. Oral immunization with the CPY2052 sonicate and cholera toxin protected against infection with strain CPY2052 in both types of mouse. These findings suggested that IFN-gamma may play a protective role in H. pylori infection, although the degree of its protective ability was estimated to be low. In contrast, in a long-term infection test done to examine the contribution of IFN-gamma to gastric inflammation, CPY2052-infected wild-type mice developed a severe infiltration of mononuclear cells in the lamina propria and erosions in the gastric epithelium 15 months after infection, whereas CPY2052-infected IFN-gamma-/- mice showed no inflammatory symptoms. This result clearly demonstrated that IFN-gamma plays an important role in the induction of gastric inflammation caused by H. pylori infection.

Adjuvants, Immunologic↗
PubMed1998

Electro-optic Properties of Colloidal Crystals As Studied by Reflection Spectroscopy.

Electro-optic properties of colloidal crystals of silica spheres in the exhaustively deionized aqueous suspension have been studied by the reflection spectroscopy using a T-type cell. Acoustic shear waves are induced when sine-wave electric fields ranging from 0.01 to 1 Hz are applied. Modulation effects of the crystals on the applied AC fields such as phase delay, change in response intensity, waveform transformation, and harmonics generation are observed. The shear waves propagate outside the electrodes where the electric field is absent. The synchronous fluctuation of the colloidal spheres including expanded electrical double layers in the crystal lattice will be one of the main causes of the electro-optic nature of the crystals. Copyright 1998 Academic Press.

Journal Article↗
PubMed1998

Analysis of the 13C-urea breath test for detection of Helicobacter pylori infection based on the kinetics of delta-13CO2 using laser spectroscopy.

We have previously reported on laser spectroscopy as a simple alternative to mass spectrometry. To validate a simplified 13C-urea breath test (UBT) with laser spectroscopy for the detection of Helicobacter pylori in clinical use, we evaluated the optimal time of breath sample collection. The 13C-UBT was carried out on each of 102 infected and 70 non-infected subjects (32 without eradication and 38 after eradication therapy). Breath samples were taken at five time points within 60 min followed by 100 mg of 13C-urea administration. The ratio of 13CO2 to 12CO2 was measured using laser spectroscopy and the recovery of tracer in the exhaled breath was calculated. Results were compared with histological and culture examinations of gastric biopsies to establish the infection status. For statistical evaluation of 13C-UBT, the optimal timing of breath sample collection was examined on the basis of the kinetics of delta-13CO2. In 32 H. pylori-negative patients (without therapy), the mean +/- 2SD of delta-13CO2 was at its minimum 20 min after urea ingestion whereas in H. pylori-positive patients, the mean +/- SD delta-13CO2 was maximum at 20 min. In addition, receiver operating characteristic (ROC) curve analysis showed that the cut-off value was estimated between 2.5-3.0 per mil (%0) at 20 min before therapy. Based on the histology and culture results, the sensitivity, specificity and positive and negative predictive values were 98.0%, 100%, and 94.1%, respectively. In conclusion, 13C-UBT with laser spectroscopy is a non-invasive, simple, sensitive and specific test to determine H. pylori status. Our findings suggest that in clinical use, measurements made at 20 min after substrate administration could be recommended for most sensitive and specific 13C-UBT results.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1998

Chemokines in the gastric mucosa in Helicobacter pylori infection.

BACKGROUND: Although chemokines have been suggested to play an important role in Helicobacter pylori associated gastritis, few studies have investigated the role of chemokines other than interleukin 8 (IL-8) in gastric mucosa. AIMS: To investigate the expression and production patterns of various chemokines using gastric biopsy specimens. METHODS: In 192 patients, expression patterns of C-X-C chemokines (IL-8 and growth regulated alpha (GRO alpha)) and C-C chemokines (regulated on activation, normal T cell expressed and presumably secreted (RANTES), monocyte chemotactic and activating factor (MCAF), macrophage inflammatory protein 1 alpha (MIP-1 alpha), and MIP-1 beta) were examined using reverse transcription polymerase chain reaction (RT-PCR) and enzyme linked immunosorbent assay (ELISA). cagA gene was identified using PCR. RESULTS: H pylori infection was associated with increased rates of expression of mRNA for IL-8, GRO alpha, RANTES, and MIP-1 alpha and with increased levels of mucosal IL-8 and GRO alpha. IL-8 and GRO alpha levels correlated with the density of H pylori in both the antrum and corpus. The levels of these chemokines correlated with cellular infiltration in the antrum but not the corpus. cagA gene positive H pylori infection was associated with increased rates of expression of mRNA for IL-8 and GRO alpha and with increased levels of these chemokines. CONCLUSION: H pylori infection is associated with increased expression rates and production of C-X-C chemokines (IL-8 and GRO alpha), but not with increased production of C-C chemokines. Although H pylori infection is associated with increased C-X-C chemokines in the antrum and corpus, there is a difference in the inflammatory response between these two areas of the stomach.

Adult↗
PubMed1998

[Combination chemotherapy with cis-platinum and ifosfamide for hormone unresponsive prostate cancer].

PURPOSE: There is no effective therapy against hormone refractory prostate cancer. This led us to evaluate the effectiveness and toxicity of cis-platinum (CDDP) and ifosfamide (IFM) combination chemotherapy in the patients with hormone-unresponsive carcinoma of the prostate. METHODS: Patients with hormone-unresponsive prostate cancer were scheduled to receive CDDP 70 mg/m2 intravenously on day 1 and IFM 1.2 g/m2/day intravenously on day 1 through day 5 of 28-day cycle. RESULTS: Twenty seven patients with hormone unresponsive prostate cancer were enrolled onto this trial. Of these patients, seven (26%) demonstrated a partial objective response (PR), and ten (37%) a stable disease (ST). The response duration of PR cases lasted from 6 to 49 months with a median of 16 months and the response duration of PR + ST cases lasted from 3 to 36 months with a median of 10 months. Subjective improvement was obtained in 11 patients (41%). Survival duration of all cases were 4 to 89 months with a median of 23 months and probabilities of survival at 3 years and 5 years were 36% and 24%, respectively. The toxicity of this treatment was mostly mild to moderate, anemia (96%), leukocytopenia (89%), anorexia (81%), alopecia (67%), thrombocytopenia (44%), hematuria (38%), renal dysfunction (19%) and liver dysfunction (7%) were noticed. Severe toxicity was observed in two cases, one acute renal failure and one endotoxin shock. CONCLUSION: We conclude that CDDP and IFM combination chemotherapy was active regimen for hormone unresponsive prostate cancer.

Aged↗
PubMed1998

[Asymptomatic pancreatic islet cell tumor (glucagonoma): case report].

A case of asymptomatic pancreatic islet cell tumor (glucagonoma) is reported. A 36-year-old woman undergoing a ultrasonic scan was found to have two masses in the body and tail of the pancreas measuring 5 cm and 4 cm in diameter, respectively. Investigations of serum peptide hormones revealed an elevated glucagon level of 27,500 pg/ml (normal < 100 pg/ml), suggesting the possibility of an islet cell tumor (glucagonoma). The patient, however, was asymptomatic although high levels of glucagon were present. The patient underwent distal pancreatectomy to remove the lesions in the body and tail of the pancreas. Histological findings revealed islet cell tumors of the pancreas, and immuno histochemical staining of the tumor cells demonstrated a positive reaction for chromogranin and glucagon.

Adult↗
PubMed1998

[Role of cytokines in the pathogenesis of gastrointestinal diseases associated with Helicobacter pylori infection].

It is well known that Helicobacter pylori can cause gastritis, gastroduodenal ulcers and malignant diseases. The infiltration of polymorphonuclear leukocytes is recognized in the lesions of these diseases, and the infiltration disappears by antibiotic therapy. However, it is not yet clarified how Helicobacter pylori induces the formation of lesions including leukocyte infiltration. Recently, we have confirmed that several kinds of cytokines are expressed in the gastric biopsy specimens of gastroduodenal diseases. Especially, it is conjectured that chemokines such as interleukin-8 (IL-8) which are expressed in the specimens, induce leukocyte infiltration, gastric mucosal inflammation and gastroduodenal ulcers. It is possible that Helicobacter pylori CagA gene is closely related with IL-8 expression because this cytokine is more strongly expressed in the specimens from the patients infected with CagA-positive Helicobacter than those with CagA-negative one.

Anti-Bacterial Agents↗
PubMed1997

Regression of atypical lymphoid hyperplasia after eradication of Helicobacter pylori.

A rare case of endoscopic and histological regression of a gastric lymphoid mucosal lesion after eradication of Helicobacter pylori is reported. A 72-year-old man was suspected of having a low-grade B-cell gastric mucosa-associated lymphoid tissue (MALT) lymphoma by endoscopic and histological findings. Histology of biopsy specimens showed massive infiltration of atypical lymphocytes and lymphoepithelial lesions. Immunohistochemical staining revealed kappa light chain expression in the infiltrated atypical lymphocytes to be twofold that of lambda light chain. The above diagnosis was thus highly suspected but not confirmed. Antibiotic therapy was given on the basis of evidence of H. pylori infection. Successful eradication of H. pylori resulted in remarkable improvement of endoscopic and histological findings. Follow-up studies were carried out 8 months after eradication, with no evidence of relapse. The eradication of H. pylori appears to be an effective alternative therapy for B-cell lymphoproliferative disease, although longer follow-up and further studies are needed before this treatment can be established.

Aged↗
PubMed1997

Bisbenzylisoquinoline alkaloids from Stephania cepharantha and their effects on proliferation of cultured cells from the murine hair apparatus.

Bisbenzylisoquinoline alkaloids were isolated from Stephania cepharantha Hayata and their proliferative activities on cultured hair cells from the murine skin were evaluated. Cepharanthine (1), cepharanoline (9), isotetrandrine (2), and berbamine (7) showed significant activities in the range of 0.01-0.1 microgram/ml, but had no activity on cultured keratinocytes or fibroblasts from the murine skin.

Alkaloids↗
PubMed1997

Spinal conduction block by intrathecal ketamine in dogs.

In addition to its use for intravenous (I.V.) anesthesia, ketamine can provide pain relief in humans when administered spinally. To elucidate the mechanisms of intrathecal (I.T.) ketamine analgesia, we observed differences in the effects of I.V. and I.T. ketamine on intraspinal evoked potentials (ISEPs) in 28 dogs anesthetized with pentobarbital. Bipolar extradural electrodes were inserted at the cervical and lumbar regions of the spinal cord for recording descending ISEPs represented by the two negative deflections, Waves I and II. I.V. ketamine 2 and 10 mg/ kg did not affect the amplitude and latency of Wave I, whereas the large dose (10 mg/kg) significantly decreased the amplitude but not the latency of Wave II. I.T. ketamine 1 and 5 mg/kg caused significant dose-dependent decreases in both Wave I and II amplitudes and prolongations of both Wave I and II latencies. These I.T. effects on ISEPs are consistent with previous in vitro observations that ketamine blocks axonal conduction. We conclude that axonal conduction block may contribute to the analgesic mechanism of I.T. ketamine.

Anesthesia, Spinal↗
PubMed1997

Sulfidoleukotriene release test (CAST) in hypersensitivity to nonsteroidal anti-inflammatory drugs.

There is a great need to develop a method for making an accurate and reliable in vitro diagnosis of adverse hypersensitivity reactions to drugs. We measured the amount of sulfidoleukotriene (sLT) released from the peripheral blood leukocytes obtained from 25 patients who developed hypersensitivity reactions following the administration of nonsteroidal anti-inflammatory drugs (NSAIDs); 12 patients demonstrated reactions to Voltaren, 8 patients to Bufferin, and 5 patients to Sedes G. The stimulation index, the ratio of the amounts of sLT (pg/ml) incubated with and without drugs, was considerably higher in the patients than in the controls, which consisted of 5 nonallergic healthy subjects. The sensitivity of the CAST (cellular antigen stimulation test) was evaluated to range from 62.5 to 80%, while the specificity was 70-100%. The CAST may thus be useful as a novel in vitro test system in order to screen for possible hypersensitive reactions to NSAIDs with both reliability and safety.

Adult↗
PubMed1997

Norreticuline and reticuline as possible new agents for hair growth acceleration.

(S)-Norreticuline and (S)-reticuline have been shown to stimulate the proliferation of cultured cells from the murine hair apparatus significantly. Furthermore, these activities were found on cultured hair cells, but not on cultured keratinocytes or fibroblasts from murine skin. In addition, (S)-norreticuline significantly stimulated mouse hair regrowth. These results suggest that (S)-norreticuline and (S)-reticuline could have specific activities on hair apparatus cells and might be useful as active compounds for accelerating hair growth.

Alkaloids↗
PubMed1996

Identification of a 79-kDa heparin-binding fibroblast growth factor (FGF) receptor in rat hepatocytes and its correlation with the different growth responses to FGF-1 between hepatocyte subpopulations.

We reported previously that the potency of heparin-binding fibroblast growth factor-1 (FGF-1) as a mitogen for rat hepatocytes in primary culture is as high as that of epidermal growth factor (EGF) and hepatocyte growth factor. To gain insight into the pathophysiological significance of FGF-1 in hepatocyte growth, we analyzed the cooperative mitogenicity of FGF-1 and EGF. Results from a nuclear labeling assay using [3H]thymidine suggest that most hepatocytes in primary culture consist of two cell populations that differ in response to FGF-1; one is an FGF-1-responsive cell population, and the other is an EGF-responsive (but not FGF-1-responsive) cell population. On the other hand, autoradiographic analysis of 125I-FGF-1 binding demonstrated that high affinity FGF receptors were homogeneously distributed on the surface of all hepatocytes. Cross-linking 125I-FGF-1 to the nonstimulated hepatocyte surface indicated that the high affinity FGF receptors comprise two FGF receptors that differ in molecular mass (128 and 79 kDa). Furthermore, the 79-kDa receptor was preferentially down-regulated when the hepatocytes were stimulated with EGF or hepatocyte growth factor. These data suggest that the abundant expression of the 79-kDa FGF receptor on some populations of hepatocytes is involved in their lack of response to FGF-1. The 128- and 79-kDa FGF receptors were assigned as FGFR2 using an antibody specific to the ectodomain of FGFR2, whereas the 79-kDa receptor was not reactive to the antibody against the carboxyl terminus of FGFR2. This 79-kDa FGF receptor was not tyrosine-phosphorylated in response to FGF-1 stimulation, while the 128-kDa FGF receptor was recognized by anti-phosphotyrosine antibody under the same conditions. Also, the heterodimer of 79- and 128-kDa FGF receptors was less tyrosine-phosphorylated than the homodimer of 128-kDa FGF receptors. These data suggest that the 79-kDa FGF receptor inhibits the function of the 128-kDa FGF receptor through their heterodimerization. Thus, we surmise that the difference in response to FGF-1 between the cell populations of normal rat hepatocytes was caused by the different levels of the 79-kDa FGF receptor in each cell population.

Animals↗
PubMed1996

A novel chimeric fibroblast growth factor for liver parenchymal cells.

Although fibroblast growth factor 1 (FGF-1) (formerly known as acidic FGF) but not FGF-2 (or basic FGF), has been suggested to play a pathophysiological role in liver regeneration, its clinical application has been restricted by its limited mitogenecity and heparin dependence. We report here that a chimeric human FGF protein, FGF-C(1211), is a heparin-independent potent mitogen for liver parenchymal cells both in vitro and in vivo. In the presence of serum and physiological concentration of insulin, FGF-C(1211) by itself induces as much as 55% of hepatocytes in culture to proliferate and up to 88% when used in combination with hepatocyte growth factor or epidermal growth factor. Furthermore, hepatocytes nuclear labeling in vivo with bromodeoxyuridine was markedly enhanced when FGF-C(1211) was injected intravenously into carbon tetrachloride-administered mice. Because FGF-C(1211) is heparin independent and nonantigenic, it has potential for clinical and preclinical applications.

Animals↗