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Biomedical subjects

S Arai

Publications and source records attributed to S Arai.

At least 91 records · Page 5Linked to original sources
PubMed2000

Staphylococcal scalded skin syndrome with prosthetic valve endocarditis.

We report staphylococcal scalded skin syndrome (SSSS) in a 67-year-old man. He showed diffuse erythema with erosion on his face and erythema with giant desquamation on his neck, axilla, genitalia, chest and abdomen 39 days after a coronary artery bypass graft and aortic valve replacement. He died of cardiac rupture caused by myocardial necrosis, and autopsy findings demonstrated prosthetic valve endocarditis due to a strain of exfoliative toxin-B producing methicillin-resistant Staphylococcus aureus. To the best of our knowledge, this is the first case of SSSS caused by prosthetic valve endocarditis.

Aged↗
PubMed2000

[Occurrence of angioimmunoblastic T-cell lymphoma six months after onset of Lyme disease].

A 68-year-old man, who had suffered a tick bite one week previously, consulted his home doctor because of fever and an erythematous rash around the bite scar. He underwent a skin biopsy, and Borrelia garinii was detected, from which Lyme disease was diagnosed. He received amoxicillin for two weeks and his symptoms disappeared. After 6 months he noticed swelling of his cervical, axillary and inguinal lymph nodes. A biopsy sample was taken from a left cervical lymph node, and this revealed angioimmunoblastic T-cell lymphoma. The patient achieved a complete remission after chemotherapy. The relationship between Lyme disease and lymphoma is discussed.

Aged↗
PubMed1999

A novel BTB/POZ transcriptional repressor protein interacts with the Fanconi anemia group C protein and PLZF.

Fanconi anemia (FA) is an autosomal recessive cancer susceptibility syndrome. The phenotype includes developmental defects, bone marrow failure, and cell cycle abnormalities. At least eight complementation groups (A-H) exist, and although three of the corresponding complementation group genes have been cloned, they lack recognizable motifs, and their functions are unknown. We have isolated a binding partner for the Fanconi anemia group C protein (FANCC) by yeast two-hybrid screening. We show that the novel gene, FAZF, encodes a 486 amino acid protein containing a conserved amino terminal BTB/POZ protein interaction domain and three C-terminal Krüppel-like zinc fingers. FAZF is homologous to the promyelocytic leukemia zinc finger (PLZF) protein, which has been shown to act as a transcriptional repressor by recruitment of nuclear corepressors (N-CoR, Sin3, and HDAC1 complex). Consistent with a role in FA, BTB/POZ-containing proteins have been implicated in oncogenesis, limb morphogenesis, hematopoiesis, and proliferation. We show that FAZF is a transcriptional repressor that is able to bind to the same DNA target sequences as PLZF. Our data suggest that the FAZF/FANCC interaction maps to a region of FANCC deleted in FA patients with a severe disease phenotype. We also show that FAZF and wild-type FANCC can colocalize in nuclear foci, whereas a patient-derived mutant FANCC that is compromised for nuclear localization cannot. These results suggest that the function of FANCC may be linked to a transcriptional repression pathway involved in chromatin remodeling.

Amino Acid Sequence↗
PubMed1999

The occurrence of polymorphism of mannose 6-phosphate/insulin-like growth factor 2 receptor gene in laboratory and wild rats.

Carcinogen-resistant inbred DRH rat strain was established from closed colony Donryu rats in the presence of 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB). Despite using 3'-Me-DAB during the stage of selection, the DRH rats developed normally and did not show any spontaneous tumor at over 1 year of age. In the present study, we examined the polymorphism in mannose 6-phosphate/insulin-like growth factor 2 receptor (M6p/Igf2r) gene and found that the DRH rat showed CCC (Proline)-type polymorphism in exon 48 and the Donryu rat had GCC (Alanine) sequence. Since the DRH rat was developed from the Donryu rat, we examined whether this polymorphism in exon 48 of M6p/Igf2r gene was due to mutation that occurred at the stage of selection in the presence of 3'-Me-DAB, using several other laboratory and wild rats. We detected the presence of polymorphism at the same site of the M6p/Igf2r gene among these rats. It is likely that the polymorphism in exon 48 of the M6p/Igf2r gene is present broadly in rats since ancient times and not due to the mutation during the course of selection unless this site is a hot spot for chemical carcinogens.

Alanine↗
PubMed1999

Activation of Arc gene, a dendritic immediate early gene, by middle cerebral artery occlusion in rat brain.

The effect of middle cerebral artery (MCA) occlusion on the activity-regulated cytoskeleton-associated protein (Arc) mRNA expression has been investigated using in situ hybridization. It was induced in the extensive regions of cerebral cortex, medial striatum, and distant areas such as the ipsilateral lateral septal nucleus, bilateral hippocampal formation and contralateral amygdala following MCA occlusion. In the hippocampal formation, it was induced in the granule cell layer and the stratum pyramidale at 1 h and in the molecular layer and in the stratum oriens and stratum radiatum bilaterally at 4 h. MK-801 pretreatment strongly attenuated the induction of Arc mRNA. The present results suggest that Arc may play an important role in the neuronal plasticity through NMDA activation following focal cerebral ischemia.

Animals↗
PubMed1999

Induction of Rheb mRNA following middle cerebral artery occlusion in the rat.

Rheb is a recently identified member of the Ras super-family and is an immediate early gene that is rapidly and transiently induced in the hippocampal granule cells by NMDA-dependent synaptic activity in the long term potentiation paradigm. The close homologies with Ras and its rapid inducibility strongly suggest that Rheb shares many biochemical and signaling properties with Ras. The present study investigated the effect of middle cerebral artery (MCA) occlusion on the expression of Rheb mRNA in the rat brain. In situ hybridization autoradiography showed that Rheb mRNA was induced in the extensive regions of cerebral cortex and medial striatum surrounding the ischemic region and bilateral hippocampal formation following MCA occlusion. The induction of Rheb mRNA in the cingulate cortex persisted prominently at 24 h of MCA occlusion. Although the Rheb mRNA induction in the medial striatum and hippocampal formation decreased after 8h of occlusion, it still remained significant at 24h of occlusion. The data suggest the possibility that Ras signaling pathways can be implicated in the cerebral ischemia-elicited events through NMDA receptor activation.

Animals↗
PubMed1999

A gustatory cyclic nucleotide-gated channels CNGgust, is expressed in the retina.

Cyclic nucleotide-gated (CNG) channels are essential proteins that contribute to the intracellular signal transduction of the senses of sight and smell. Recently, we found a novel CNG channel (CNGgust) in rat taste buds, and demonstrated its possible involvement in taste signal transduction. In the present study, we used RT-PCR and immunostaining to prove that this gustatory CNG channel is expressed in the outer segments of rat cone photoreceptor cells. The study strongly suggests that the senses of taste and sight share, at least in part, a common signal transduction pathway.

Animals↗
PubMed1999

Involvement of wiskott-aldrich syndrome protein in B-cell cytoplasmic tyrosine kinase pathway.

Bruton's tyrosine kinase (Btk) has been shown to play a role in normal B-lymphocyte development. Defective expression of Btk leads to human and murine immunodeficiencies. However, the exact role of Btk in the cytoplasmic signal transduction in B cells is still unclear. This study represents a search for the substrate for Btk in vivo. We identified one of the major phosphoproteins associated with Btk in the preB cell line NALM6 as the Wiskott-Aldrich syndrome protein (WASP), the gene product responsible for Wiskott-Aldrich syndrome, which is another hereditary immunodeficiency with distinct abnormalities in hematopoietic cells. We demonstrated that WASP was transiently tyrosine-phosphorylated after B-cell antigen receptor cross-linking on B cells, suggesting that WASP is located downstream of cytoplasmic tyrosine kinases. An in vivo reconstitution system demonstrated that WASP is physically associated with Btk and can serve as the substrate for Btk. A protein binding assay suggested that the tyrosine-phosphorylation of WASP alters the association between WASP and a cellular protein. Furthermore, identification of the phosphorylation site of WASP in reconstituted cells allowed us to evaluate the catalytic specificity of Btk, the exact nature of which is still unknown.

Agammaglobulinaemia Tyrosine Kinase↗
PubMed1999

Reversibility and hierarchy of thermal transition of hen egg-white lysozyme studied by small-angle x-ray scattering.

To clarify mechanisms of folding and unfolding of proteins, many studies of thermal denaturation of proteins have been carried out at low protein concentrations because in many cases thermal denaturation accompanies a great tendency of aggregation. As small-angle x-ray scattering (SAXS) measurements are liable to use low-concentration solutions of proteins to avoid aggregation, SAXS has been regarded as very difficult to observe detailed features of thermal structural transitions such as intramolecular structural changes. By using synchrotron radiation SAXS, we have found that the presence of repulsive interparticle interaction between proteins can maintain solute particles separately to prevent further aggregation in thermal denaturation processes and that under such conditions the thermal structural transition of hen egg-white lysozyme (HEWL) holds high reversibility even at 5% w/v HEWL below pH approximately 5. Because of the use of the high concentration of the solutions, the scattering data has enough high-statistical accuracy to discuss the thermal structural transition depending on the structural hierarchy. Thus, the tertiary structural change of HEWL starts from mostly the onset temperature determined by the differential scanning calorimetry measurement, which accompanies a large heat absorption, whereas the intramolecular structural change, corresponding to the interdomain correlation and polypeptide chain arrangement, starts much prior to the above main transition. The present finding of the reversible thermal structural transitions at the high protein concentration is expected to enable us to analyze multiplicity of folding and unfolding processes of proteins in thermal structural transitions.

Animals↗
PubMed1999

Ultrastructural localization of S100A3, a cysteine-rich, calcium binding protein, in human scalp hair shafts revealed by rapid-freezing immunocytochemistry.

We have characterized the subcellular distribution of S100A3, a cysteine-rich calcium binding protein, in human scalp hair shaft. This was accomplished using rapid-freezing immunocytochemistry, a technique that combines rapid-freezing, freeze-substitution fixation without chemical fixatives, and subsequent electron microscopic detection of immunocytochemical labeling. This technique preserves both the antigenicity and the ultrastructural integrity of fully keratinized tissues, which are highly unmanageable when prepared for immunoelectron microscopy. In the hair shaft, S100A3 was primarily identified in the endocuticle and was also present in the intermacrofibrillar matrix surrounding macrofibril bundles of intermediate filament keratins in cortex cells. Double immunolabeling of S100A3 and hair keratins revealed the in situ spatial relationship between them. In the endocuticle, S100A3 was present on the inner portion of the endocuticle adjacent to the cell membrane complex, whereas hair keratins were present on the outer portion. These results provide the first ultrastructural evidence that an S100 protein is localized in specific subcompartments in human hair cells. (J Histochem Cytochem 47:525-532, 1999)

Adolescent↗
PubMed1999

Antisense oligonucleotide complementary to the BamHI-H gene family of Marek's disease virus induced growth arrest of MDCC-MSB1 cells in the S-phase.

DNA synthesis was effectively inhibited by antisense oligonucleotide A1 complementary to the BamHI-H gene family in Marek's disease virus (MDV)-derived lymphoblastoid MDCC-MSB1 cells. When a cell cycle distribution of a total cell population was analyzed by flow cytometry, the proportion of S-phase cells increased in the cell populations by treatment with oligonucleotide A1. Approximately 60-70% of the cells appeared in the S phase for 24 and 36 hr of incubation in the presence of oligonucleotide A1 (20-30% in the untreated control cells). The inhibition of cell cycle progression by treatment with oligonucleotide A1 was reversible. When the cells were treated with 5 microM aphidicolin for 12 hr, a similar pattern of cell cycle distribution was observed to that obtained after treatment with oligonucleotide A1. Aphidicolin is an inhibitor of cellular DNA polymerase alpha, and it halts progression of the cell cycle at the G1/S border or early S phase. When the cells were treated with aphidicolin for 12 hr and subsequently incubated with oligonucleotide A1, no significant difference was observed in the cycle phase distribution of cells in the presence and absence of oligonucleotide A1. In contrast, when the cells were treated with oligonucleotide A1 for 12 hr and subsequently incubated with aphidicolin, the cell cycle did not progress from the G1/S border or early S phase to the next phase.

Animals↗
PubMed1999

Preparation of antibodies directed to the Babesia ovata- or Theileria sergenti-parasitized erythrocytes.

To investigate the surface antigens of the bovine red blood cells (RBCs) parasitized by Babesia ovata or Theileria sergenti, attempts were made to produce monoclonal antibodies (mAbs) with BALB/c mice. Comparable numbers of hybridomas producing anti-piroplasm mAbs, as well as anti-bovine RBC mAbs, were obtained from the mice immunized with B. ovata- or T. sergenti-PRBCs. However, mAbs directed to the surface of parasitized RBCs (PRBCs) were obtained only from the mice immunized with B. ovata-PRBCs, but not from those immunized with T. sergenti-PRBCs. When serum samples from the immunized mice and the infected cattle were examined, antibodies recognizing B. ovata-PRBC surface were detected in the sera against B. ovata, but analogous antibodies were undetectable in the sera against T. sergenti, despite that the sera showed substantial antibody titers to T. sergenti piroplasms. The results suggest that significant antigenic modifications occur on the surface of B. ovata-PRBCs, but not on the surface of T. sergenti-PRBCs.

Animals↗
PubMed1999

Abnormal accumulation of G2/M-phase cells from LEC strain rats after X-irradiation at S phase.

The effect of X-irradiation on the progression of the cell cycle in cell lines from LEC and WKAH rats was investigated by a flow cytometer. When the cells were exposed to 5 Gy of X-rays at S phase, the proportion of S-phase cells in both cell populations decreased with incubation time and that of G2/M-phase cells was approximately 80% at 6 hr post-irradiation. At 12 hr post-irradiation, approximately 45% of the WKAH rat cells appeared in the G1 phase. However, 80-90% of LEC rat cells remained in the G2/M phase and less than 5% in the G1 phase during 6-12 hr post-irradiation. Thus, the LEC rat cells irradiated at S phase remained in the G2/M phase for at least 6 hr longer than did the WKAH rat cells.

Animals↗
PubMed1999

Short-term longitudinal changes in subcutaneous fat distribution and body size among Japanese women in the third decade of life.

This research clarified the changes in body shape among Japanese women aged in their 20's, by measuring the subcutaneous fat distribution over the whole body and its circumference at certain points. The subjects, 13 healthy women, were measured twice, once in their early 20's and 5 years later in their late 20's. Subcutaneous fat thickness was measured at 14 points on the body using the B-mode ultrasound method and the body size was measured directly at 8 points on the body using a steel measure. Subcutaneous fat thickness tends to increase with age, except at the cheek, neck, bust and leg. Significant increases were detected especially at lower parts of the trunk such as the waist and infragluteal region. Meanwhile, despite the significant change in subcutaneous fat thickness, the circumferences measured did not change, and also weight tended to decrease with age. Based on this finding, except for fat, body mass, such as muscle and bone, decreases with age due to decreased exercise and changes in calorie intake. Cluster analysis of the accumulation patterns of subcutaneous fat indicated that there were the following 3 patterns of subcutaneous fat accumulation from the early 20's to the late 20's. I. Accumulation on the whole trunk (bust, abdomen, waist and back) and upper arm--trunk/upper arm accumulation pattern. II. Significant accumulation around waist--waist accumulation pattern. III. Even accumulation at abdomen, side abdomen, hip and lower hip--abdomen/hip accumulation pattern.

Adipose Tissue↗
PubMed1999

Perceived, actual, and seasonal changes in the shape of the face, hands and legs.

In this study, we measured the shape of the face, legs, hands and fingers during the course of a day to determine the amount of swelling. We examined the relationship between the perception of swelling and the degree of actual swelling, and considered the influence of seasonal factors. The topology of the face was measured using the 3D curved shape measuring apparatus, VOXELAN, while the circumference of the legs and fingers and the volume of the hands were also recorded. The measurements were used to determine the amount of change in each parameter, which was then used to determine the degree of swelling. The subjects for the experiment were 10 healthy Japanese women aged 24 to 30 years of standard build (BMI: 19.3-25.0). Measurements were carried out twice a day in the mornings and afternoon, first between 8:30 and 10:00 a.m. and then between 4:00 and 5:30 p.m. At each measurement session, subjects were asked if they perceived swelling to have occurred. We investigated the relationship between the degree of actual swelling and the reported perception of swelling. We also investigated the influence of seasonal factors by conducting the same tests on the same subjects in summer (August 1997) and in winter (February-March 1998). The relationship between perceived and actual swelling differs depending on the part of the body. For the face, actual swelling correlates strongly with perceived swelling. This trend is particularly noticeable for the upper eyelids. For the thigh and lower leg, on the other hand, there was no significant difference. The frequency with which subjects reported the perception of swelling varied depending on the area of the body, and was generally extremely low for the thighs, hands and fingers. With respect to seasonal variation, swelling in the face, hands and feet tended to be more pronounced during the summer. In the facial region, the biggest difference was in the lower eyelid, where swelling increased more than five times. This level of variation suggests that the atmospheric temperature is the main factor affecting swelling.

Adult↗
PubMed1999

Pseudogout attack associated with chronic thyroiditis and Sjögren's syndrome.

A 66-year-old woman, diagnosed with chronic thyroiditis at age 63, presented with anorexia and fatigue. Therapy for the chronic thyroiditis consisted of levothyroxine sodium (100 microg/day). Her symptoms were attributed to the insufficient supply of levothyroxine sodium. Following a dosage increase to 150 microg/day, she suffered from an acute attack of pseudogout. Clinical features were complicated by Sjögren's syndrome, which appeared after treatment onset. Pseudogout was effectively treated by colchicine after administration of diclofenac sodium failed to alleviate the symptoms. Pseudogout is a recognized complication of thyroid replacement therapy, but association with Sjögren's syndrome has not been previously reported.

Aged↗