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Biomedical subjects

S Saitoh

Publications and source records attributed to S Saitoh.

At least 253 records · Page 14Linked to original sources
PubMed1995

[Clinical application of digital TV tomosynthesis to disorders of the wrist and their post-operative evaluation].

The clinical utility of digital TV tomosynthesis was assessed in 13 patients with chronic disorders of the wrist and the first carpometacarpal joints, and a post-operative evaluation was carried out. The disorders included nonunion of the scaphoid in five patients, Kienböck's disease in four, subluxation of the distal radioulnar joint in two, and osteoarthrosis of the first carpometacarpal joint in two. The total time needed to obtain two sets of tomographs of a wrist by digital TV tomosynthesis was about 10 minutes, or approximately one third of the time required with conventional methods. The total radiation exposure in obtaining all tomographs of one direction with digital TV tomosynthesis was less than that in obtaining only one tomograph with conventional methods. Digital TV tomosynthetic images were judged superior to conventional tomographs by four orthopedic surgeons and four radiologists, because tomographic blur was reduced in part by a spatial frequency filter processing. Clinically, digital TV tomosynthesis was very helpful in evaluating nonunion of the scaphoid and Kienböck's disease, especially in their post-operative conditions with metallic fixative devices. Digital TV tomosynthesis was found to be a fast, feasible and inexpensive method with low radiation exposure for evaluating disorders of the wrist.

Adult↗
PubMed1995

Serial hemodynamic measurements in well-differentiated hepatocellular carcinomas.

We performed serial hemodynamics in 15 patients with 21 well-differentiated hepatocellular carcinomas. The total length of the observation period ranged from 129 to 678 days (median, 368). We investigated both arterial and portal blood flow at intervals of at least 4 months. Arterial blood flow was measured with carbon dioxide-enhanced ultrasonography (US), and portal blood flow was measured with computed tomographic arterial portography (CTAP). None of the tumors were hypervascular on the initial study; however, by the final study nine nodules (42.9%) had become homogeneously hypervascular, two (9.5%) had become partially hypervascular, and the others did not change. Of 10 nodules without portal blood supply on any study, 8 became hypervascular by the final study. Of 11 nodules with portal blood supply on the initial study, a follow-up study showed no change in portal flow in 6 and the loss of portal flow in 5. Four of these five became hypervascular, with a documented loss of portal flow before the increase in arterial flow. The doubling time of tumors with a homogeneous increase in arterial blood flow ranged from 89 to 333 days (median, 172), whereas the doubling time of other tumors ranged from 227 to 607 days (median, 392). Thus, growth rate and vascularity in well-differentiated hepatocellular carcinoma are closely correlated. When the well-differentiated hepatocellular carcinoma has portal blood flow and is not hypervascular, it grows slowly. On the other hand, when it loses portal blood flow and becomes hypervascular, it grows rapidly.

Adult↗
PubMed1994

Serum des-gamma-carboxyprothrombin concentration determined by the avidin-biotin complex method in small hepatocellular carcinomas.

BACKGROUND: Des-gamma-carboxyprothrombin (DCP) is a useful tumor marker for hepatocellular carcinoma (HCC). The present method for measurement of DCP concentration, however, does not have adequate sensitivity to detect small HCCs. METHODS: The serum DCP concentration was investigated by the avidin-biotin complex (ABC) method in patients with an HCC smaller than 20 mm in maximum dimension. A serum DCP concentration greater than 4.0 arbitrary units per liter using the ABC method was considered abnormal. RESULTS: Of 115 patients with small HCC, 45 (39.1%) had an abnormal DCP concentration. Ten of 141 patients with chronic hepatitis (7.1%), 18 of 115 (15.7%) with cirrhosis, and 0 of 30 normal control patients had abnormal DCP concentrations. This method yielded a sensitivity of 39.1%, a specificity of 89.1%, a positive predictive value of 61.6%, and a negative predictive value of 76.5% for detection of small HCC. The detectability of HCC increased to 56.5% when alpha-fetoprotein (AFP) was was measured (> 40 ng/ml). Abnormal DCP concentrations were seen in 8 of 34 (23.5%), 24 of 42 (57.1%), and 5 of 7 (71.4%) patients with Edmondson's Grade I, II, and III tumors, respectively. There was a significant relationship between DCP concentrations and histologic grade (P = 0.0017), but there was no association between DCP concentration and other patient characteristics. Elevation of serum AFP concentrations in patients with hepatitis B surface antigen positivity, however, was more frequent than that in patients who were antihepatitis C virus (HCV) positive. Therefore, the measurement of serum DCP concentrations may be more useful than that of serum AFP concentrations in patients with anti-HCV positivity. CONCLUSIONS: The measurement of serum DCP concentrations by the ABC method is a useful diagnostic tool for the monitoring of small HCC.

Adult↗
PubMed1994

Hippocalcin expression in the brain of the Snell dwarf mutant mouse.

To determine factors contributing to the expression of the brain-derived protein, hippocalcin, we mapped its distribution in the brain of Snell pituitary dwarf mutant mice (dw) by immunohistochemical and immunoblot methods. Our findings are as follows. (1) In the hippocampus, hippocalcin immunoreactivity was found in the cell body and dendrites of pyramidal neurons of the normal controls and dw mice, although the intensity of immunoreactivity in the dw mice was lower. (2) In the cerebellum, hippocalcin immunoreactivity was strongly expressed in the Purkinje cell body of both the control and dw mice. However, the Purkinje cell dendrites were found to be more intensely stained in the dw mice than in the normal controls. (3) In the dw cerebral cortex, the pyramidal neurons of layers II to VI strongly expressed hippocalcin, whereas its expression in the controls was weak. (4) The amount of hippocalcin in the dw hippocampus was less than in the normal controls, whereas the amount in the dw cerebral cortex and cerebellum was greater. These results indicate that the developmental expression of hippocalcin in the dw brain is affected by the retarded maturation of the neuronal network due to the deficient hormonal state (the lack of growth and thyroid hormones).

Animals↗
PubMed1994

Fission yeast cut3 and cut14, members of a ubiquitous protein family, are required for chromosome condensation and segregation in mitosis.

Fission yeast temperature-sensitive mutants cut3-477 and cut14-208 fail to condense chromosomes but small portions of the chromosomes can separate along the spindle during mitosis, producing phi-shaped chromosomes. Septation and cell division occur in the absence of normal nuclear division, causing the cut phenotype. Fluorescence in situ hybridization demonstrated that the contraction of the chromosome arm during mitosis was defective. Mutant chromosomes are apparently not rigid enough to be transported poleward by the spindle. Loss of the cut3 protein by gene disruption fails to maintain the nuclear chromatin architecture even in interphase. Both cut3 and cut14 proteins contain a putative nucleoside triphosphate (NTP)-binding domain and belong to the same ubiquitous protein family which includes the budding yeast Smc1 protein. The cut3 mutant was suppressed by an increase in the cut14+ gene dosage. The cut3 protein, having the highest similarity to the mouse protein, is localized in the nucleus throughout the cell cycle. Plasmids carrying the DNA topoisomerase I gene partly suppressed the temperature sensitive phenotype of cut3-477, suggesting that the cut3 protein might be involved in chromosome DNA topology.

Amino Acid Sequence↗
PubMed1994

Molecular and clinical study of 61 Angelman syndrome patients.

We analyzed 61 Angelman syndrome (AS) patients by cytogenetic and molecular techniques. On the basis of molecular findings, the patients were classified into the following 4 groups: familial cases without deletion, familial cases with submicroscopic deletion, sporadic cases with deletion, and sporadic cases without deletion. Among 53 sporadic cases, 37 (70%) had molecular deletion, which commonly extended from D15S9 to D15S12, although not all deletions were identical. Of 8 familial cases, 3 sibs from one family had a molecular deletion involving only 2 loci, D15S10 and GABRB3, which define the critical region for AS phenotypes. The parental origin of deletion, both in sporadic and familial cases, was exclusively maternal and consistent with a genomic imprinting hypothesis. Among sporadic and familial cases without deletion, no uniparental disomy was found and most of them were shown to inherit chromosomes 15 from both parents (biparental inheritance). A discrepancy between cytogenetic and molecular deletion was observed in 14 (26%) of 53 patients in whom cytogenetic analysis could be performed. Ten (43%) of 23 patients with a normal karyotype showed a molecular deletion, and 4 (13%) of 30 patients with cytogenetic deletion, del(15) (q11q13), showed no molecular deletion. Most clinical manifestations, including neurological signs and facial characteristics, were not distinct in each group except for hypopigmentation of skin or hair. Familial cases with submicroscopic deletion were not associated with hypopigmentation. These findings suggested that a gene for hypopigmentation is located outside the critical region of AS and is not imprinted.

Adolescent↗
PubMed1994

Molecular cloning of a novel calcium-binding protein structurally related to hippocalcin from human brain and chromosomal mapping of its gene.

A cDNA clone (hHLP2) encoding a novel calcium-binding protein structurally related to hippocalcin has been isolated from the human hippocampus cDNA library. The primary structure consists of 193 amino acids, and contains three EF-hand structures and a possible NH2-terminal myristoylation site. A single transcript at a position corresponding to 1.7 kilobases was detected only in the brain. The hHLP2 gene was mapped to human chromosome 2.

Amino Acid Sequence↗
PubMed1994

Expression of hippocalcin in the developing rat brain.

Expression of hippocalcin in the developing rat brain was investigated by a combination of Northern blot, in situ hybridization, immunoblot and immunohistochemical methods. In the hippocampus, hippocalcin mRNA and immunoreactivity first appeared in the CA3 pyramidal cells on embryonic day 19 (E19) and postnatal day 1 (P1), respectively, and extended throughout Ammon's horn. After P14, the hippocampal pyramidal cells, especially in the CA1 region, maintained the highest expression level among the brain regions. The dentate granule cells expressed a small amount of hippocalcin mRNA and immunoreactivity from P7 and maintained a low level through the developmental stages. In the cerebral cortex, hippocalcin mRNA and immunoreactivity appeared in the pyramidal cells of the piriform cortex from P1 and P4, respectively. Their expression extended throughout the cerebral cortex and reached the maximum level on P14, and then declined gradually with age to half of the maximum level by adults. In the cerebellum, a few Purkinje cells expressed a small amount of hippocalcin mRNA and immunoreactivity on P7. Their expression became evident in most of the Purkinje cells on P14 and increased gradually by P28. Then, their expression declined with age; however, the immunoreactivity was concentrated in the cell bodies and proximal segments of the dendrites in adults. These results suggest that the expression of hippocalcin mRNA and protein is strictly controlled by both the cell type and the developmental process and that hippocalcin plays a role in neuronal differentiation in the early stages of development and may relate to other neuronal function in the adult brain.

Animals↗
PubMed1994

Immunohistochemical localization of neural visinin-like Ca(2+)-binding protein 2 in adult rat brain.

The distribution of neural visinin-like Ca(2+)-binding protein 2 (NVP2) in adult rat brain was analyzed by immunoblot and immunohistochemical methods. NVP2 immunoreactivity was expressed intensely in the pyramidal cells of the CA1 and 2 regions of Ammon's horn, the granule cells of the dentate gyrus and the pyramidal cells of the cerebral cortex layers II to VI, moderately in the pyramidal-shaped cells of the anterior olfactory nucleus and large spindle-shaped cells of the globus pallidus, and weakly in neurons in the nucleus accumbens and the anterior and dorsomedial thalamus. In most cell types, NVP2 immunoreactivity was located in the cytoplasm and plasma membrane of the cell bodies and dendrites.

Animals↗
PubMed1994

Molecular cloning of human hippocalcin cDNA and chromosomal mapping of its gene.

We have isolated a cDNA clone encoding human hippocalcin from a human hippocampus cDNA library. This clone (hHLP1) consists of 840 nucleotides, including the entire open reading frame of 582 nucleotides, 10 nucleotides of the 5' leader and 248 nucleotides of the 3' noncoding regions. Comparison of the human hippocalcin sequence with the corresponding rat sequence revealed an amino acid identity of 100% and nucleotide identity of 92%. Northern blot analysis showed that a single transcript at a position corresponding to 2.0 kb was detected only in the brain. The human hippocalcin gene was mapped to chromosome 1 by amplification of human hippocalcin-specific DNA fragment on DNA from human-rodent somatic cell hybrids by using the polymerase chain reaction.

Amino Acid Sequence↗
PubMed1994

Isochromosome 15q of maternal origin in two Prader-Willi syndrome patients previously diagnosed erroneously as cytogenetic deletions.

Since our previous report on two Prader-Willi syndrome (PWS) patients with t(15q;15q) (Niikawa and Ishikiriyama; Hum Genet 69:22-27, 1985) was erroneous, we report here new data and a corrected interpretation. Reexamination of the parental origin of their t(15q;15q) using polymorphic DNA markers that are mapped to various regions of 15q documented no molecular deletions at the 15q11-q13 region in either patient. Both patients were homozygous at all loci examined and their haplotypes on 15q coincided with one of those in their respective mothers. These results indicate that the presumed t(15q;15q) in each patient was actually an isochromosome 15q producing maternal uniparental disomy, consistent with genomic imprinting at the PWS locus.

Aneuploidy↗
PubMed1994

Excess functional copy of allele at chromosomal region 11p15 may cause Wiedemann-Beckwith (EMG) syndrome.

Wiedemann-Beckwith syndrome (WBS) is a genetic disorder with overgrowth and predisposition to Wilms' tumor. The putative locus of the gene responsible for this syndrome is assigned to chromosome region 11p15.5, and genomic imprinting in this region has been proposed: the paternally derived gene(s) at 11p15.5 is selectively expressed, while the maternally transmitted gene(s) is inactive. We examined 18 patients for the parental origin of their 11p15 regions. DNA polymorphism analyses using 6 loci on chromosome 11 showed that 2 patients with duplications of 11p15 regions from their respective fathers and one from the mother, indicating the transmission of an excessive paternal gene at 11p15 to each patient. Our results, together with the previous findings in karyotypically normal or abnormal patients and in overgrowth mouse experiments, are consistent with imprinting hypothesis that overexpression of paternally derived gene(s) at 11p15.5, probably the human insulin-like growth factor II (IGF-II) gene, may cause the phenotype. Total constitutional uniparental paternal disomy (UPD) or segmental UPD for the 6 loci examined of chromosome 11 was not observed in our 12 sporadic patients. In order to explain completely the inheritance of this syndrome in patients with various chromosomal constitutions, we propose an alternative imprinting mechanism involving the other locus that may be paternally imprinted and may suppress the expression of this gene.

Alleles↗
PubMed1994

Muscle glycogen repletion and pre-exercise glycogen content: effect of carbohydrate loading in rats previously fed a high fat diet.

We have recently reported that rates of muscle glycogen repletion during the early period of recovery were increased by carbohydrate (CHO) loading in rats previously fed a high fat diet. However, the reason for this remained unanswered. The purpose of this study was to examine whether an increase of glycogen utilization due to an elevated pre-exercise glycogen store would enhance rates of glycogen repletion in muscle. Despite an equal degree of glycogen depletion, the rates of glycogen repletion of soleus, red and white gastrocnemius muscles by postexercise administration of glucose (3.0 g.kg-1 body mass) and citrate (0.5 g.kg-1 body mass) were faster in the CHO loaded (3 days) rats than in the nonloaded rats, as a result of elevated pre-exercise glycogen content and consequently the greater glycogen utilization. The higher rate of muscle glycogen repletion may in part be explained by increased postexercise glycogen synthase activity.

Animal Feed↗
PubMed1994

Specific detection of positive and negative stranded hepatitis C viral RNA using chemical RNA modification.

Since hepatitis C virus (HCV), a major causative agent of posttransfusional non-A, non-B hepatitis, is a positive stranded RNA virus, it is supposed to replicate via a negative RNA strand. Although strand specific reverse transcription-polymerase chain reaction (RT-PCR) method was recently developed to detect each strand of HCV RNA, the specificity of the strategy has remained to be determined. In this study, using in vitro transcribed positive and negative stranded HCV RNAs mixed with hepatic cellular RNA from normal liver, we found that this strategy did not distinguish between the two RNA strands, but that chemical modification of RNA samples at the 3' end followed by strand specific RT-PCR made specific detection possible. Liver tissues, sera and peripheral blood mononuclear cells (PBMC) from ten patients with chronic HCV infection were analyzed with the novel strategy of RT-PCR combined with RNA modification. Positive and negative strands of HCV RNA were detected in liver tissues of ten (100%) and nine (90%) cases, respectively. Negative RNA strand was detected also in sera of five cases (50%), positive strand being detected in nine cases (90%). In PBMC, positive strand of HCV RNA was detected in eight cases (80%), whereas negative strand in only one case (10%), suggesting that HCV has much less cellular tropism to PBMC than to hepatocytes.

Adult↗
PubMed1994

Interferon retreatment of nonresponders with HCV-RNA-positive chronic hepatitis C.

Interferon has been shown to be an effective treatment for some patients with chronic hepatitis C. In this study, the value of retreatment of nonresponders to interferon was investigated. Thirty-eight patients with hepatitis C virus (HCV)-RNA-positive chronic hepatitis C who had been treated with beta-interferon but still showed an alanine aminotransferase (ALT) level > 50 KU upon completion of therapy were retreated with alpha-interferon. Eight patients (21.1%) had normalization of ALT levels for at least 6 months after the completion of retreatment. The factors related to normalization of ALT levels after interferon retreatment were studied. Of 16 patients with transient HCV-RNA negativity 1 month after the initial interferon therapy, 7 (43.8%) had a complete response, with normalization of ALT levels and undetectable HCV-RNA, more than 6 months after interferon retreatment. On the other hand, of the 22 patients with HCV-RNA activity 1 month after the initial interferon therapy, only 1 (4.5%) had a complete response. Multivariate analysis, using a multiple logistic model, indicated that a complete response to readministration of interferon was most strongly correlated to transient negative conversion for HCV-RNA after the initial course of treatment.

Alanine Transaminase↗
PubMed1994

Evaluation of transvaginal color Doppler sonography, transvaginal sonography and CA 125 for prediction of ovarian malignancy.

OBJECTIVES: To evaluate the efficacy of color Doppler ultrasonography as the predictor of malignant ovarian tumors and to compare the results with CA 125 levels and ultrasonographic morphological patterns. METHODS: We compared color Doppler ultrasound with sonographic findings and serum CA 125 levels for predicting ovarian malignancy in 16 patients with malignant and 12 patients with benign ovarian tumors. RESULTS: There was a significant difference in pulsatility index (PI) value of ovarian vessel between benign and malignant tumors (2.42 +/- 0.67 for benign and 1.35 +/- 0.78 for malignant, respectively, P < 0.01). The specificity of morphological findings and CA 125 was lower than that of PI measurements, but sensitivity was not different between the three methods. In addition, the combination of color Doppler and CA 125 or morphological assessments resulted in a sensitivity of 100% and a negative predictive value of 100%, respectively. CONCLUSION: PI measurements by transvaginal color Doppler ultrasound combined with CA 125 levels or morphological findings could be an accurate and appropriate screening method for ovarian tumors.

Adult↗
PubMed1994

Arterial grafting with the telescoping anastomotic technique for arterial defects.

An arterial graft was taken from the left femoral artery of the rat and grafted into the right femoral artery using the telescoping anastomotic technique at both the proximal and distal anastomoses to compare the patency rate with that of the vein grafts interposed into the arterial defect with the same telescoping technique. The time required for each anastomosis was about 10 minutes and all of the 31 grafts remained patent without application of xylocaine, yielding a higher patency rate than the vein grafts interposed in an arterial defect. The telescoping technique proved to be so dependable that it could be used at least twice in an artery. Inserting one vessel stump into another using the telescoping technique may not itself be responsible for the failure of vein grafts interposed in an arterial defect, but distortion of the slack venous wall of the graft by high arterial blood pressure is.

Anastomosis, Surgical↗