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H Nishitani

Publications and source records attributed to H Nishitani.

At least 55 records · Page 3Linked to original sources
PubMed1998

[Cone beam CT utilizing a rotational digital radiographic system: early clinical experience on pulmonary and skeletal lesions].

Utilizing a rotational digital radiographic system (SF-VA 100, Hitachi) 289 digital images were obtained during a 360-degree rotation in 4.8 seconds. The images were transferred to a high-speed workstation and post-processed to create volume data in 9 minutes. The multi-planar reconstruction method reconstructed high-quality tomographic images with equal resolution in any direction. We applied this system as a cone beam CT in order to demonstrate pulmonary and spinal lesions. Early clinical experience suggested the usefulness of the method in the evaluation of diseases in organs with high radiographic contrast.

Arteriovenous Fistula↗
PubMed1997

A dual-specificity phosphatase Cdc25B is an unstable protein and triggers p34(cdc2)/cyclin B activation in hamster BHK21 cells arrested with hydroxyurea.

By incubating at 30 degrees C in the presence of an energy source, p34(cdc2)/cyclin B was activated in the extract prepared from a temperature-sensitive mutant, tsBN2, which prematurely enters mitosis at 40 degrees C, the nonpermissive temperature (Nishimoto, T. , E. Eilen, and C. Basilico. 1978. Cell. 15:475-483), and wild-type cells of the hamster BHK21 cell line arrested in S phase, without protein synthesis. Such an in vitro activation of p34(cdc2)/cyclin B, however, did not occur in the extract prepared from cells pretreated with protein synthesis inhibitor cycloheximide, although this extract still retained the ability to inhibit p34(cdc2)/cyclin B activation. When tsBN2 cells arrested in S phase were incubated at 40 degrees C in the presence of cycloheximide, Cdc25B, but not Cdc25A and C, among a family of dual-specificity phosphatases, Cdc25, was lost coincidentally with the lack of the activation of p34(cdc2)/cyclin B. Consistently, the immunodepletion of Cdc25B from the extract inhibited the activation of p34(cdc2)/cyclin B. Cdc25B was found to be unstable (half-life < 30 min). Cdc25B, but not Cdc25C, immunoprecipitated from the extract directly activated the p34(cdc2)/cyclin B of cycloheximide-treated cells as well as that of nontreated cells, although Cdc25C immunoprecipitated from the extract of mitotic cells activated the p34(cdc2)/cyclin B within the extract of cycloheximide-treated cells. Our data suggest that Cdc25B made an initial activation of p34(cdc2)/cyclin B, which initiates mitosis through the activation of Cdc25C.

Animals↗
PubMed1997

Carcinoma of the uterine cervix with myocardial metastasis.

Cardiac metastasis from pelvic malignancies is rare. We experienced a case of carcinoma of the uterine cervix with myocardial involvement in the right ventricle, and treated this patient with conventional methods until her death. The metastatic tumor was incidentally found in the right ventricle, eroding the myocardium. We used CT, MRI, and gallium scintigraphy to assess the lesion. This aggressive lesion proved fatal for our relatively young patient. We report this case for future reference.

Adult↗
PubMed1997

The cdc18 protein initiates DNA replication in fission yeast.

Recent work has demonstrated that cdc18p plays a crucial role in regulating the onset of S phase in fission yeast. cdc18p is a major product of START specific transcription and associates with ORC and MCM proteins which are required for the initiation of DNA replication. High expression of cdc18p induces continuing DNA synthesis and is thought to drive the assembly of initiation complexes. In addition to its role in bringing about DNA replication, cdc18p participates in the cell cycle checkpoint control linking S phase to START and mitosis. We propose that cdc18p is central to the molecular mechanism co-ordinating S phase and M phase in concert with changes in activity of the master cell cycle regulator, the cdc2 protein kinase.

CDC2 Protein Kinase↗
PubMed1997

[Evaluation by MR imaging of the velocity and volume of pre- and postprandial portal blood flow in the presence or absence of liver cirrhosis].

PURPOSE: We measured pre- and postprandial changes in the portal flow of normal volunteers and patients with liver cirrhosis using MR imaging and examined how to quantify portal flow to evaluate liver function. MATERIALS AND METHODS: Three groups were selected: middle aged normal volunteers (mean age 37.2 yrs., 5 persons), aged normal volunteers (mean age 61.5 yrs., 6 persons), and patients (mean age 67.6 yrs., 7 persons). We used cine-PC and the spin-echo method to measure portal flow velocity (PV) and vertical sectional area (PA), respectively. We repeated measurements of PV and PA in turn for about 60 minutes after a meal. RESULT: There were no significant differences in PV between the three groups before the meal. Study after the meal also indicated no significant difference between the two normal groups. In the normal group, PV and portal flow volume (Pvol.) increased by about 77% and 127%, respectively. In the cirrhotic liver group, PV and Pvol. increased by about 14% and 32%, respectively. A significant difference was seen between the normal and patient groups after the meal. We, therefore considered that the changing rate of Pvol. might be a sensitive parameter for evaluating liver function, including reserve.

Adult↗
PubMed1997

[Basic and clinical studies of oral barium sulfate preparations for CT].

In CT examination of the abdomen and pelvis, oral iodinated contrast agents and oral barium sulfate preparations are now being used to improve diagnostic accuracy, and studies have been carried out on their clinical usefulness. Although helical CT has come into wide spread use recently, most studies have used the ordinary type of CT. There have been no reports on studies using barium sulfate preparations with helical CT. We, therefore, prepared several barium sulfate preparations with different concentrations and particle diameters, and conducted a basic study to determine the optimal conditions for helical CT. In addition, we conducted a similar study using the ordinary imaging method for comparison with helical CT. Based on the results of these studies, we conducted a clinical study with several volunteers to find the most suitable barium sulfate preparation. Our basic study compared Baritop CT and Gastrografin, and a concentration of 1.5%-2.0% was found suitable. In our examination of particle size using animal intestines, fine particles were found to be most appropriate. Although little difference was observed between the helical procedure and the ordinary imaging procedure, the possible development of artifacts specific to the helical procedure was suggested. In the clinical study, the 2.0% preparation tended to show better contrast and a better filling rate for the upper abdominal organs than the 1.5% preparation. However, little difference in artifacts was found between them. The artifacts tended to be intensified when barium migrated toward the distal portion of the small intestine. Judging from these results, a 2.0% fine particle preparation appeared to be suitable for examination of the upper abdominal organs. For organs in the pelvic region, preparations with a lower concentration were considered suitable.

Administration, Oral↗
PubMed1997

[Transverse relaxation time of metabolites by proton MRS: one of the parameters concerned with quantification].

We examined the transverse relaxation time of metabolites observed by proton MRS at 6 different points of TE(18, 30, 60, 90, 135, and 270ms). The double exponential curve was better fitted to the 6 points than the single exponential curve for calculating the T2 values of the three major metabolites. We considered that these metabolites would have a long T2 component and short T2 component, and the correct T2 value is difficult to obtain under the limitations of measurement time available in clinical applications.

Adult↗
PubMed1997

[The measurement of the coronary flow by the phase contrast method (cine PC, Fastcard PC)].

We confirmed the accuracy of flow velocity measured by two kinds of phase contrast (PC) sequence. The fast PC sequence(FCARDPC) showed a little different value from the conventional PC, but the linear correlation was found between established values of the instrument and the measured velocity by the fast PC. The flow velocity of the right and left coronary arteries in one cardiac cycle was measured using two PC sequences on the same subject. It was found that the flow velocity in one cardiac cycle was almost the same pattern between the two method, though the absolute values of each other differed slightly. We considered that the comparison in the same sequence would be acceptable even in clinical cases unless the values measured by a different sequence or modality were compared directly. Though our experience on diseases are still preliminary, we suggest that myocardial ischemia and dysfunction will be related with not only the decrease of velocity but also the change of flow pattern of the coronary artery in one cardiac cycle. We believe that this method has a potential becoming one of the routine methods for evaluating cardiac functions.

Blood Flow Velocity↗
PubMed1997

[Accuracy and clinical utility of quantitative proton magnetic resonance spectroscopy (MRS) on phantom and chronic cerebral ischemia].

We quantified the concentration of metabolites observed by proton MRS using the tissue water signal as an internal standard. A phantom containing known concentrations of NAA (10 mM) and Cr (5 mM) was used for the study of methodological accuracy. Clinical utility was evaluated by the measurement of patients with severe stenosis or obstruction of the unilateral internal carotid artery. The concentration of tissue water was compensated using a proton-density weighted image measured with a water bag attached to the head. The calculated concentrations of NAA and Cr in the phantom were 9.2 mM (SD: 1.2) and 5.6 mM (SD: 0.7), respectively. On the ischemic side of the brain, the concentrations of NAA and Cr were lower than on the opposite side, but the concentration of choline (Cho) was almost the same on the two sides. The NAA/Cr ratio showed no statistically significant differences between the two sides, because the concentration of Cr was shown to be decreased in the ischemic area. We consider that quantitative evaluation of proton MRS might reveal changes in single metabolites clearly, thereby facilitating understanding of the results of proton MRS.

Aspartic Acid↗
PubMed1996

Therapeutic efficacy of a case of pyruvate dehydrogenase complex deficiency monitored by localized proton magnetic resonance spectroscopy.

We experienced a case of pyruvate dehydrogenase deficiency observed by proton magnetic resonance spectroscopy (1H MRS). This case was diagnosed as West syndrome by characteristic convulsion and the periodic hypsarrhythmia pattern of EEG. At the age of 11 months, the first examination of 1H MRS revealed a high peak of lactate, and the high concentration of lactate and pyruvate was confirmed in sampled cerebrospinal fluid (CSF). Deficiency of pyruvate dehydrogenase complex was finally diagnosed by genetic examination. Dichloroacetate was administered to the patient as therapy. Decrease of lactate in the brain was found by 1H MRS. Lactate and pyruvate in the CSF was also decreased. In accordance with the suspension of dichloroacetate, increase of lactate in the brain was detected and the convulsions reappeared. After readministration of dichloroacetate, the patient was almost symptom free and lactate in the brain and CSF had decreased to the normal extent. We considered that 1H MRS provides useful information for screening metabolic disorders of infants and assessing the efficacy of therapy.

Brain↗
PubMed1996

A hamster temperature-sensitive G1 mutant, tsBN250 has a single point mutation in histidyl-tRNA synthetase that inhibits an accumulation of cyclin D1.

BACKGROUND: We have previously isolated a series of temperature-sensitive mutants for cell-proliferation from the BHK21 cell line, derived from the golden hamster. These mutants proliferate at 33.5 degrees C, the permissive temperature, but not at 39.5 degrees C the restrictive temperature. Using DNA-mediated gene transfer, human genes complementing these ts mutants were cloned. RESULTS: At 39.5 degrees C the tsBN250 cell line, a temperature-sensitive mutant of the BHK21 cell line, had a defect in the G1 phase, but not in the S phase. The human gene complementing tsBN250 cells was found to encode histidyl-tRNA synthetase. Indeed, the tsBN250 cell line had a single base change--guanine to adenine at the second position of the 362nd codon of hamster histidyl-tRNA-synthetase, converting arginine to histidine. Following release from serum starvation, cyclin E, but not cyclin D1, was accumulated, while, at 39.5 degrees C, the mRNA of cyclin D1 was normally expressed in tsBN250 cells. A similar inhibition of cyclin D1 accumulation was observed in another ts mutant, tsBN269, which has a single point mutation in lysyl-tRNA synthetase. Overexpression of cyclin D1 enabled tsBN250 cells to enter the S phase. CONCLUSION: tsBN250 cells have a single point mutation in histidyl tRNA synthetase that causes a loss of histidyl-tRNA synthetase activity which in turn reduces the content of cyclin D1, but not of cyclin E, thereby resulting in G1 arrest.

Amino Acid Sequence↗
PubMed1996

Case of a parathyroidectomized patient observed longitudinally by ultrasonography. Relationship between the growth rates and 1,25-dihydroxyvitamin D3 receptor contents in the parathyroid glands.

Parathyroid glands enlarge gradually with the progression of secondary hyperparathyroidism. The significance of down-regulation of the 1,25-dihydroxyvitamin D receptor (VDR) in parathyroid glands has been emphasized. Here we report a case in whom the relationship between the growth rates of the parathyroid glands and their VDR content was examined. A 36-year-old man, who had been hemodialyzed for 8.8 years because of chronic renal failure due to chronic glomerulonephritis, developed severe secondary hyperparathyroidism. The first ultrasonographic examination of the parathyroid glands, performed 10 months before parathyroidectomy, revealed that the sizes of the right upper (RU) and left upper (LU) glands were 10 x 8 x 5 and 14 x 10 x 9 mm3, respectively, although the right lower (RL) and left lower (LL) glands were not detected. The second ultrasonographic examination performed 5 days before PTX revealed that the RU gland had enlarged up to 24 x 12 x 10 mm3, while the LU gland remained unchanged at 16 x 9 x 8 mm3. At this time, the sizes of the RL and LL glands were determined only in the longitudinal section to be 10 x 5 and 4 x 3 mm2, respectively. In the excised specimens, the sizes and weights of the RU and RL glands were 25 x 10 x 9 mm3 and 1,950 mg and 17 x 10 x 8 mm3 and 1,160 mg, respectively, while those of the LU and LL glands were 16 x 10 x 7 mm3 and 850 mg and 9 x 8 x 7 mm3 and 350 mg, respectively. Histopathologic study demonstrated that the RU and RL glands exhibited nodular hyperplasia, while the LU and LL glands exhibited diffuse hyperplasia. Using a ligand binding assay, the VDR content of the rapidly growing RU and RL glands were significantly reduced to 32.6 +/- 9.6 and 32.7 +/- 5.2 fmol/mg protein, respectively, as compared to that of the LU gland with no significant proliferating activity (111.8 +/- 0.8 fmol/mg protein). It is of great interest that the smallest LL gland, which showed some proliferating potential in spite of a histologic pattern of diffuse hyperplasia, has a VDR content of 41.0 +/- 2.6 fmol/mg protein. In summary, it was implied from this case that the VDR content in the parathyroid gland might reduce as the growth rate of the parathyroid gland increases and, furthermore, that the VDR content seems to depend to some degree on the histopathologic pattern rather than on gland weight.

Adult↗
PubMed1996

Relative activity of N-(beta-D-glucopyranosyl)nicotinic acid to nicotinic acid as a niacin nutrient in rats and in Lactobacillus plantarum ATCC 8014.

We investigated the relative activity of N-(beta-D-glucopyranosyl)-nicotinic acid as a niacin nutrient in rats and in Lactobacillus plantarum ATCC 8014. N-(beta-D-Glucopyranosyl)-nicotinic acid is a detoxified product or storage form of nicotinic acid that is found in plants. The relative activity of N-(beta-D-glucopyranosyl)nicotinic acid to nicotinic acid in rats was 1/2.3, 1/2.2, 1/1.0, and 1/1.7 as indices of the body weight gain, food intake, blood NAD content, and the increased urinary excretion of niacin and its metabolites, respectively. N-(beta-D-Glucopyranosyl)nicotinic acid had no niacin activity in Lactobacillus plantarum ATCC 8014.

Animals↗
PubMed1996

[Age-dependent changes in metabolites of the normal brain in childhood : observation by proton MR spectroscopy].

We investigated aging-dependent changes in proton magnetic resonance spectroscopy (1H-MRS) of the normal brain in childhood, and observed differences in the four portions of the brain. Measurement by 1H-MRS was carried out on the frontal lobe, parietotemporal lobe, temporal lobe and cerebellum. The NAA/Cho ratio increased rapidly in the period from 0 to 2 years of age in all portions except for the cerebellum, and gradually increased after three years of age. The number of measurements of the cerebellum was not sufficient to reach a conclusion, but no clear aging-related change was found. The Cho/Cr ratio decreased according to the neural development in all portions except the cerebellum. Because the T2 relaxation time of water after four years of age was almost the same as that of young adults, we used the relaxation times specified in the literature to quantify the metabolites observed by 1H-MRS. The subjects used for quantification were aged from 4 to 12 years. The concentration of NAA in the temporal lobe was the lowest of the four portions, and that of Cho and Cr in the cerebellum was the highest in four portions. These results could not be obtained by signal ratios alone, and we considered that the quantification of metabolites is necessary for a better understanding of 1H-MRS. This study showed that the results of 1H-MRS vary depending on age and the portion in the brain. Our results may serve as a normal basis for the detection of pathological changes by 1H-MRS.

Adolescent↗
PubMed1996

[Magnetic resonance studies of dentato-rubro-pallido-luysian atrophy--correlation with clinical severity and age of onset].

Dentato-rubro-pallido-luysian atrophy (DRP-LA) is a rare autosomal dominant neurodegenerative disorder. Recently the genetic abnormality has become clear. We encountered four patients with DRPLA (including a 14-year-old boy and his father) in whom the final diagnosis was made by DNA analysis. In addition to performing conventional MRI, we quantified brain metabolites by proton MR spectroscopy. We also compared the expanded repeat size of CAG trinucleotide in a gene on the short arm of chromosome 12 to the MR findings which consisted of the findings of clinical severity and age of onset. The method reported by Nagafuchi et al. was used to determine the size of the CAG repeat on the focus chromosome. Repeat size was closely correlated with age at onset and disease severity. The MR studies were performed with a Magnetum H-15SP (Siemens, 1.5 Tesla) equipped with a C-P type head coil. Axial T2-WIs (TR = 2000 ms, TE = 90 ms) and T1-WIs (TR = 200 ms, TE = 15 ms) were measured. Atrophy of the brainstem, the tegmentum, and the cerebellum, and periventricular hyperintensity could be seen. The sequence for 1H-MRS was PRESS, voxel size was 8 ml, and regions of interest were placed on right basal ganglia and right parietal white matter. After compensating the observed signals, we obtained metabolite concentrations by using compensated water intensity as an internal standard. Despite the absence of abnormalities of the basal ganglia on MRI, NAA concentrations differed from patient to patient and were low in severe clinical cases. We propose that the CAG repeat size of the focus chromosome and NAA concentration quantified by 1H-MRS are closely correlated with clinical severity and age of onset. In conclusion, DNA analysis may be useful in early diagnosis and 1H-MRS can detect metabolic abnormalities non-invasively even when no markedly abnormal findings can be detected with other clinical modalities.

Adolescent↗
PubMed1996

[Myocardial metastasis in the right ventricle from uterine cervical carcinoma with high 67Ga-citrate accumulation: a case report].

We report a case of high 67Ga-citrate accumulation with myocardial metastasis in the right ventricle from uterine cervical carcinoma. A 41-year-old woman was admitted to our hospital because of acute abdomen after operation and radiotherapy for uterine cervical carcinoma. On performing 67Ga-scintigraphy for differentiation from fever of unknown origin, we found significant 67Ga-citrate accumulation in the right ventricle. To the best of our knowledge, this is a rare case.

Adult↗
PubMed1996

[A case of recurrent squamous cell carcinoma of cervix successfully treated with BOMP].

Combination chemotherapy consisting of bleomycin, vincristine, mitomycin C and cisplatin (BOMP) was applied to a case (57 years old) with recurrence of squamous cell carcinoma of the cervix. The patient with FIGO stage IIIb cervical carcinoma had been treated with radiotherapy seven years ago. She was affected by malignant pericardial effusion, and was treated with direct intrapericardial administration of cisplatin (20 mg). After instillation, ultrasonography and computed tomography showed the wall thickening of colon and marked ascites. Barium enema showed the circumferential narrowing and serrations of colon, and it was diagnosed to be carcinomatous peritonitis. She was treated with BOMP consisting of BLM (5 mg, i.m., days 1 - 5), VCR (1 mg, i.v., day 5'), MMC (8 mg, i.v., day 5), and CDDP (70 mg, d.i.v., day 5). After three courses of BOMP therapy, she achieved a complete response with few toxic effects and did not require special care. She has been free of disease for six months and her performance status is 0. This encouraging result warrants the use of this combination chemotherapy regimen in other patients with recurrent squamous cell carcinoma of the cervix.

Antineoplastic Combined Chemotherapy Protocols↗