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Biomedical subjects

T Ichikawa

Publications and source records attributed to T Ichikawa.

At least 199 records · Page 11Linked to original sources
PubMed1998

Postnatal developmental changes in NSE and NNE mRNA expression in the rat pineal gland: in situ hybridization histochemistry.

By in situ hybridization, neuron-specific enolase (NSE) and non-neuronal enolase (NNE) mRNAs were examined in the rat pineal gland at the postnatal developmental and adult stages. The distributions of hybridized signals were analyzed in comparison with immunohistochemical staining of synaptophysin (SYN), which is a marker for pinealocytes. In SYN-positive areas that were observed throughout postnatal developmental and adult stages, we detected both NSE and NNE signals, which increased simultaneously during early postnatal development and thereafter became stationary. Quantitative analysis revealed that NNE signals were 2- to 3-fold greater in number than NSE signals at any given stage. This predominant expression pattern of NNE differed from that in neurons, which usually showed both signals at similar levels and seemed to reflect the difference in physiological function from neurons. During the early postnatal stages, a cord-like arrangement of cells without distinct SYN staining was observed. This arrangement was the thickest at postnatal day 0 and became dispersed and thinner with development, showing a relationship with formation of vascularized connective tissue stroma. By in situ hybridization, many of the constituent cells showed weak NNE signals but no distinct NSE signals. However, some cells also showed weak NSE signals, suggesting heterogeneity of these cells. The characteristic NSE and NNE expression patterns in the pineal gland cells clarified in this study might provide a basis for further studies of the differentiation and function of the pineal gland.

Animals↗
PubMed1998

Distinct effects of tetragastrin, histamine, and CCh on rat gastric mucin synthesis and contribution of NO.

Although gastrin, histamine, and carbachol (CCh) accelerate gastric mucin metabolism, information about their target cells of mucin production is lacking. To clarify this, we examined the effects of these stimulants, including the possible participation of nitric oxide (NO), on mucin biosynthesis in distinct sites and layers of rat gastric mucosa. Pieces of tissue obtained from the corpus and antrum were incubated in a medium containing radioactive precursors and each stimulant, with or without NO synthase (NOS) inhibitor. Distribution of NOS was compared with that of the specific mucins by immunostaining using specific antiserum and monoclonal antibodies. In the full-thickness corpus mucosa, tetragastrin enhanced [3H]glucosamine incorporation into mucin but had no effect on [14C]threonine incorporation. Both histamine and CCh dose dependently increased 3H- and 14C-labeled corpus mucin. Only CCh stimulated antral mucin biosynthesis. CCh stimulation was noted in the corpus mucosa after removal of surface mucous cells, but stimulation by tetragastrin or histamine disappeared as a result of this pretreatment. Only tetragastrin-induced activation was completely blocked by the NOS inhibitor. NOS immunoreactivity was limited to surface mucous cells. Mucus-producing cells present in the different sites and layers of the gastric mucosa have distinct mechanisms for regulation of mucin biosynthesis. Gastrin-stimulated mucin biosynthesis mediated by NO is limited to surface mucous cells of rat gastric oxyntic mucosa.

Animals↗
PubMed1998

Relationship of prostate-specific antigen levels to prostate volume and age in mass screening subjects.

To evaluate the relationship between prostate-specific antigen (PSA) levels and prostate volume and age in a mass screening for prostatic disease, a total of 1,162 examinees from one Japanese prefecture who were over 45 years of age underwent a mass screening for prostatic disease that used the Hybritech (Tandem(R)RIA) kit, and the prostate volume was estimated by transabdominal ultrasonography. Differences among several groups of men according to prostate volume and age were examined by multiple comparisons using ranks. When some subjects visited several times, the data of the first visit were adopted only. The total number of individual subjects in this study was 589 men. The multiple comparisons using ranks and 10-year age brackets revealed that the levels of PSA showed significant differences between only two pairs of groups stratified by age. In contrast, the levels of PSA showed significant differences among seven pairs of groups stratified by the prostate volume according to 10-ml brackets. When a logarithmic transformation of the serum levels of PSA was used, the results showed the same tendencies. From the results of the present study, it can be said that the PSA reference range calculated with stratified prostate volume might be more useful in the detection of prostate cancer than that calculated with stratified age.

Aged↗
PubMed1998

[Analysis of angiographic computed tomography with rapid helical scan. Clinical usefulness for the diagnosis of hepatocellular carcinoma].

PURPOSE: The aim of this study was to clarify the clinical usefulness of combined CT during arterial portography (CTAP), and CT arteriography (CTA), for the diagnosis of hepatocellular carcinoma. MATERIALS AND METHODS: CTAP and CTA were performed in 58 patients with a combined 144 hepatocellular carcinoma (HCC) lesions. Arterial vascular access was obtained through bilateral punctures of the femoral artery with selective placement of catheters in the hepatic artery and superior mesenteric artery. CT scans were performed first during injection of contrast media into the superior mesenteric artery, followed by repeated imaging of the liver during injection of contrast media into the hepatic artery. Delayed CT (DCT) was also obtained 5 min after CTA. RESULTS: The detection rates for all 144 lesions were 73.6% with conventional contrast enhanced CT, 90.3% with CTAP, 95.8% with CTA, 87.5% with DCT, and 98.6% with combined CTAP and CTA. Of early HCC lesions (n = 18), 88.9%, 33.3%, 77.8%, 100%, and 88.9% were detected by conventional contrast enhanced CT, CTAP, CTA, DCT, and combined CTAP and CTA, respectively. Of classical HCC lesions (n = 126), 71.4%, 98.4%, 98.4%, 85.7%, and 100% were detected by conventional contrast enhanced CT, CTAP, CTA, DCT, and combined CTAP and CTA, respectively. CONCLUSION: Combining CTAP and CTA improved the radiologist's ability to detect lesions with confidence and to differentiate perfusion abnormalities of HCCs.

Adult↗
PubMed1998

Effect of roxatidine bismuth citrate (MX1) against acetylsalicylic acid- and indomethacin-induced gastric mucosal damage in rats.

We have studied the effect of the newly synthesized agent, roxatidine bismuth citrate (N-[3-(3-(1-piperidinyl-methyl)phenoxy)propyl]-hydroxyacetamide-2- hydroxypropane-1,2,3-tricarboxylate-bismuth(3+) complex), code name MX1, against acetylsalicylic acid (ASA)- and indomethacin-induced gastric mucosal damage in rats. Effects of MX1 (12.5, 50, 125, 184, 250 mg/kg) were compared to the effects of equimolar doses of roxatidine and bismuth subcitrate. Effect of MX1 (10(-6) M) on mucin biosynthesis measured by [3H] glucosamine incorporation in rat gastric corpus has been determined. MX1-pretreatment dose-dependently decreased the mean ulcer number and length in all doses used in an extent similar to that of roxatidine and more pronounced in comparison with bismuth subcitrate. The morphometrical results have been confirmed histomorphologically. The biosynthesis of mucin was found to be significantly enhanced after MX1 addition. The results of the present study suggest that MX1 has a gastroprotective effect against ASA- and indomethacin-induced ulcers which might be due both to its H2-blocking and mucus-stimulating activity.

Animals↗
PubMed1998

Quantitative analysis of hepatitis B virus precore mutant in hepatitis type B.

Active liver disease has been detected in chronic hepatitis B after seroconversion from positive HBe antigen to positive anti-HBe antibody. Active replication of HB virus (HBV) containing a precore stop-codon mutation has been implicated in this condition. The usual methods, such as direct sequencing, to characterize the responsible mutant of HBV are not suitable for routine clinical use. Here we employed the competitive mutation site specific assay (CMSSA) to detect precore mutant HBV-DNA in patients with positive HB surface antigen. In patients with HBe antigen, precore mutant HBV-DNA was significantly higher than in patients with HBe antibody. The level of precore mutant HBV-DNA in patients with elevated serum ALT was significantly higher than in patients with normal serum ALT. Sex, age and the level of serum HBV-associated DNA polymerase levels were not correlated with levels of precore mutant HBV-DNA. Ten of 11 negative patients for the precore mutant by polymerase chain reaction followed by restriction fragment length polymorphism assay (PCRRFLP) were positive for the precore mutant by CMSSA. These results suggest that the precore mutant has already emerged in the HBeAg-positive phase as determined by CMSSA, which is more sensitive than PCR-RFLP and is useful for evaluating the clinical course of patients with chronic hepatitis B.

Adult↗
PubMed1998

Diffusion-weighted MR imaging with a single-shot echoplanar sequence: detection and characterization of focal hepatic lesions.

OBJECTIVE: The purpose of this study was to determine the usefulness of diffusion-weighted MR imaging with single-shot echoplanar imaging in characterizing focal hepatic lesions by apparent diffusion coefficient (ADC) and contrast-to-noise ratio (CNR) measurements. MATERIALS AND METHODS: Diffusion-weighted imaging on a 1.5-T MR unit was performed in 46 patients with 74 known focal hepatic lesions (11 hemangiomas, 15 metastases, and 48 hepatocellular carcinomas [HCCs]). Mean values for ADCs and CNRs of all lesions were calculated. Mean values for CNRs with diffusion-weighted imaging were also compared with those for breath-hold T2-weighted fast spin-echo images. RESULTS: The mean values for ADCs were different for each type of tumor (5.39 x 10(-3) mm2/sec +/- 1.23 in hemangiomas, 2.85 x 10(-3) mm2/sec +/- 0.59 in metastases, and 3.84 x 10(-3) mm2/sec +/- 0.92 in HCCs), and each of them was significantly greater than the mean values for ADCs of the normal liver (2.28 x 10(-3) mm2/sec +/- 1.23 in normal liver [p < .05] except metastasis versus normal liver [p < .1]). Also, the mean values for ADCs were based on differences of ADC values. Only four (6%) of 63 malignant tumors (three HCCs and one metastasis) could not be differentiated from hemangiomas. The mean value for CNRs with diffusion-weighted images (14.4 +/- 8.54 in HCC and 29.0 +/- 6.79 in metastasis) was significantly higher than the mean values for CNRs obtained with T2-weighted fast spin-echo images in both metastases and HCCs (p < .05), whereas no significant difference was seen for hemangiomas. CONCLUSION: Mean values for ADCs differed for the three types of the hepatic lesions and were higher than ADCs of the normal liver. We suggest that diffusion-weighted imaging may be useful for increased detection of HCCs and metastases and in distinguishing these entities from hemangiomas.

Carcinoma, Hepatocellular↗
PubMed1998

Characterization of hepatic lesions by perfusion-weighted MR imaging with an echoplanar sequence.

OBJECTIVE: The purpose of this study was to examine the usefulness of perfusion-weighted MR imaging with a single-shot gradient echoplanar sequence in characterizing hepatic tumors. SUBJECTS AND METHODS: Perfusion-weighted imaging was performed in 61 patients with 91 confirmed hepatic tumors (14 hemangiomas, 19 metastases, and 58 hepatocellular carcinomas). The perfusion-weighted imaging was started at the time of administration of 0.1 mmol/kg of gadolinium, and images were continuously obtained every 2 sec for 88 sec. Time-intensity curves for all the tumors were created for quantitative analysis. Patterns of enhancement were also evaluated. RESULTS: Changes in signal intensity that occurred throughout examination differed in three types of tumor. Transient signal intensity decreases in the perfusion phase significantly differed in three types of tumors (46% in hepatocellular carcinoma, 48% in hemangioma, and 15% in metastasis, p < .05 for hepatocellular carcinoma versus metastasis and for hemangioma versus metastasis). Signal intensity recovered rapidly for hepatocellular carcinoma and metastasis, whereas recovery was slower for hemangioma. Final signal intensity recovery was 94% in hepatocellular carcinoma, 91% in metastasis, and 54% in hemangioma compared with their initial signal intensities. (p < .05 for hepatocellular carcinoma versus hemangioma and for hemangioma versus metastasis.) The enhancement patterns also differed in three types of tumor. CONCLUSION: Perfusion-weighted imaging with a gradient echoplanar sequence provides real-time mapping of many points along the enhancement profile curves because of its excellent temporal resolution. Therefore, it accurately characterizes hepatic tumors based on their different negative-enhancement patterns.

Adult↗
PubMed1998

Cloning and sequencing of the rat cDNAs encoding class I beta-tubulin.

Two kinds of rat cDNA clones encoding class I beta-tubulin were isolated from the neonatal rat brain, and sequenced. They corresponded to mRNA species formed by the alternative usage of polyadenylation signals. The determined nucleotide sequence showed high (84.6%) identity to rat class II beta-tubulin, the only rat beta-tubulin sequence reported in the nucleotide database, in the coding region, but relatively low (47.3-50.7%) in the noncoding region. The Northern blot analysis using the 3'-noncoding fragment as a probe showed that both mRNA species of the class I beta-tubulin were down-regulated during brain development.

Amino Acid Sequence↗
PubMed1998

Estimation of residual stress in dental porcelain by laser-Raman spectroscopy.

Residual stress in the surface of dental porcelain was estimated using laser Raman spectroscopy. Sixteen different magnitudes of residual stress were generated in commercial porcelain disks by tempering, ion exchange, and slow cooling. The specimens were analyzed using a laser-Raman spectrometer with an Ar+ laser. The Raman shift of the largest peak near 500 cm-1 originating from silica was used as an indicator of the level of residual stress. For comparison, the residual stress in the specimen was estimated by the indentation micro-fracture method. The Raman shift of the porcelain increased with increasing residual stress at 3.7 x 10(-2) cm-1/MPa (R2 = 0.89). The increase in the Raman shift corresponded to the increase in compressive stress. In addition, the value of full width at half maximum on the peak corresponded to the residual stress (-1.57 x 10(-1) cm-1/MPa: R2 = 0.82). These results revealed that the increase of residual stress in porcelain clearly appears on the Raman spectrum as an increase in the Raman shift. It is thus feasible to estimate residual stress in porcelain by laser-Raman spectroscopy.

Aluminum Silicates↗
PubMed1998

[Bilateral pheochromocytomas with von Hippel-Lindau's disease: a case report].

A case of bilateral pheochromocytomas with von Hippel-Lindau's disease (VHL) is reported. A 46-year-old woman who had hyperglycemia was admitted to our hospital because of abdominal tumors. Her elder sister and niece had been diagnosed as VHL. Ultrasonography, CT, and MRI revealed bilateral adrenal tumors. Noradrenaline levels in serum and urine were elevated and 131I-MIBG scintigraphy showed accumulation in bilateral adrenal glands. Moreover, she had bilateral renal cysts and cerebellar hemangioblastoma. Bilateral adrenalectomies were performed and pathological diagnosis was pheochromocytoma. This is the seventh case of bilateral pheochromocytomas with VHL reported in Japan.

Adrenal Gland Neoplasms↗
PubMed1998

[Three-dimensional CT angiography for cerebral aneurysm using a multi-angle reconstruction plan method].

The purpose of this study was to evaluate the clinical usefulness of three-dimensional CT angiography (3D-CTA) for the diagnosis of cerebral aneurysm using a new reconstruction method called Multi-Angle Reconstruction Plan (MARP). The threshold values, region of interest and six angles of view were preset for the MARP method on the basis of our experience with cerebral 3D-CTA. Spiral CT angiography was performed in 27 patients with 29 aneurysms. The six images reconstructed with the MARP method were generated from the volumetric CT data. Two radiologists independently reviewed the six 3D-CT images for the presence of aneurysm. It took about five minutes to semiautomatically reconstruct the six 3D-CT images with the MARP method. There were no discrepancies in the evaluation of the 3D-CT images. Twenty-six aneurysms of 24 patients were demonstrated on the six 3D-CT images. Three aneurysms in 3 patients were not depicted on the 3D-CT images by the MARP method. In them, the additional 3D-CT images which were generated after evaluating the 2D-CT images clearly showed the aneurysms. The MARP method is considered to be a useful three-dimensional reconstruction technique for the diagnosis of cerebral aneurysm.

Adult↗
PubMed1998

[Clinical study of transcatheter arterial embolization for pulmonary arteriovenous fistula].

PURPOSE: To evaluate the efficacy of transcatheter arterial embolization for pulmonary arteriovenous fistula (PAVF). MATERIALS AND METHODS: Eight patients with 14 PAVFs were treated by TAE for feeding arteries. In 5 of 8 cases, detachable balloons were used, and, in 3 of 8 cases, metalic coils were used for embolization of the feeding arterial branch. Detachable balloons or a series of metalic coils were placed at the feeding artery proximal to the fistula. The diameter of detachable balloons was twice the diameter of the feeding arterial branch. The diameter of metalic coils was 1 mm larger than the diameter of the feeding artery. RESULTS: No complications were apparent in our cases. All PAVFs were completely occuluded by the embolization of a feeding branch. One month after the procedures, the arterial oxygen pressure increased to normal values in all cases and clinical symptoms disappeared. On postcontrast CT, the fistulas treated by the embolization of a feeding arterial branch were not enhanced. CONCLUSION: The embolization of a feeding branch provided a radical cure for PAVFs.

Adult↗
PubMed1998

[3D-CT cystography with perspective volume-rendering].

We evaluated the clinical utility of 3D-CT cystography using the perspective volume rendering technique in 5 patients with disorders of the urinary bladder and prostate. Unlike the conventional orthostatic volume-rendering technique, the capability of optional visual point settlement in the urinary bladder precluded cutting a subset of acquired data for luminal inspection, and permitted observation closer to lesions. Consequently, the technique enabled the evaluation of the accurate size, shape, and relation to adjoining mucosa and the region shaded by bulky tumor. 3D-CT cystography using the perspective volume-rendering technique facilitated 3-D inspection of the bladder lumen.

Aged↗
PubMed1998

[Appearance of extrahepatic lesions in the superior lip and orbit of a patient with liver metastases of gastric cancer following partial response by hepatic arterial infusion chemotherapy].

A 76-year-old man was totally gastrectomized in June, 1996 for advanced gastric cancer. In February, 1997, multiple liver metastases were found by abdominal CT scan, and hepatic arterial infusion chemotherapy was started with 5-FU, EPI and MMC by an implantable reservoir indwelled via the left subclavian artery. This treatment was judged to have led to a partial response because reduced focus size of the liver metastasis was revealed by CT scan and levels of tumor markers decreased significantly. However, metastatic foci were found in the skin of the superior lip and the orbit in December 1997. He was treated with a variety of therapies, but died in January, 1998. Many cases with metastatic hepatic cancer have a poor prognosis because of the appearance of extrahepatic lesions in spite of the fact that a partial response can be obtained by hepatic arterial infusion chemotherapy. The present case was unique since extrahepatic lesions appeared at very rare sites such as the superior lip and the orbit.

Aged↗
PubMed1998

[Gene transduction for experimental brain tumors using recombinant adenovirus vector].

Recent advances in molecular biology have permitted significant progress toward the treatment of malignant brain tumors using gene transduction methods. Adenovirus vectors have recently been shown to transduce genes successfully into brain tumor cells both in vitro and in vivo. We have investigated the feasibility of gene transduction for brain tumors using adenovirus vectors. To evaluate in vitro transduction rate by adenovirus vectors, rat 9L gliosarcoma cells or human glioblastoma cells were infected with recombinant replication-deficient adenovirus vectors containing the E. coli beta-galactosidase gene (Adex-CALacZ) and stained with X-Gal. We observed a multiplicity of infection (MOI)-dependent rate. Approximately 100% transgene expression was achieved at a MOI of 5 after seven days of incubation. To evaluate transgene expression in a rat brain tumor model, AdexCALacZ was stereotactically injected into established rat 9L brain tumors. Intratumoral injection of AdexCALacZ resulted in high transgene expression in tumor cells. Although injection of AdexCALacZ in the normal basal ganglia resulted in broad and diffuse transduction into endogenous neural cells, direct intratumoral injection resulted in transduction that was relatively restricted to the tumor cells as well as some neighboring normal cells. Transduction rates were relatively elevated at the margin of the tumor. Our results suggest that adenovirus vectors might be a feasible method to transfer therapeutic genes into malignant brain tumors.

Adenoviridae↗
PubMed1998

[Breath-hold MR cholangiopancreatography with 2D and 3D-FASE sequence at 0.5 tesla: evaluation based on measurements of signal intensity ratio and contrast-to-noise ratio].

Single-slice 2D-FASE (more than 2 cm) and 3D-FASE images proved to be reliable techniques by which to create high-resolution MRCP images at 0.5 T. In particular, 3D-FASE sequence can provided MIP and its thin source images with sufficient SIR and CNR of the images, which are useful to evaluate detailed structures. Using 3D-FASE sequence, even the non-dilated pancreatobiliary system can frequently be demonstrated because each source image retains satisfactory SIR and CNR of the images due to 3D acquisition and is not affected by motion artifacts of any kind. The most important problem for 3D-FASE sequence is that view-to view amplitude modulation errors may persist, though gradient moment errors can be reduced because of no actual motion during acquisition, resulting in degraded the MIP images due to the different positions of the source images in a few patients with inconstant respiration.

Biliary Tract↗