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Biomedical subjects

K Ohashi

Publications and source records attributed to K Ohashi.

At least 145 records · Page 8Linked to original sources
PubMed2000

[Chirality of natural products: hyoscyamine and scopolamine].

Monthly changes of the content-ratio between S-(-)- and R-(+)-hyoscyamine as well as those between S-(-)- and R-(+)-scopolamine in the leaves of Datura metel L. cultivated in the field, were quantitatively analyzed by the use of HPLC with a chiral adsorbent. It was found that S-(-)-isomer was predominant for hyoscyamine and the ratio of R-(+)-isomer gradually increased during the growth, whereas in the case of scopolamine, S-(-)-isomer was the sole one found throughout the cultivation period. The 1H-NMR study in the CD3OD solution has suggested that S-(-)-hyoscyamine (1) and S-(-)-scopolamine (2) take a "face-to-face" conformation between their tropane skeletons and the benzene rings of the tropic acid moieties. In the presence of an equimolar NaOD in the CD3OD solution, the racemization at C-2' of 1 and 2 proceeded more rapidly than the hydrolysis at the tropic acid ester bond, presumably due to the steric hindrance caused by their "face-to-face" conformations. In the D2O and H2O solutions, on the other hand, the racemization and the hydrolysis of 1 proceeded smoothly, while those of 2 did not occur. It has been supposed that these individual reaction manners are ascribable in considerable extent to the different basicity of N atom in each tropane skeleton of 1 and 2 and to stronger intramolecular hydrogen bond occurring between the carbonyl oxygen at C-1' and the hydroxyl group at C-3' in the tropic acid moiety of 1.

Atropine↗
PubMed2000

[Antihypertensive substance in the leaves of kumis kucing (Orthosiphon aristatus) in Java Island].

The water decoction of leaves of kumis kucing, Orthosiphon aristatus (BL.) MIQ (Lamiaceae) which has been prescribed in Javanese traditional medicine (jamu) for the treatment of hypertension etc., was partitioned into a mixture of chloroform and water. The chloroform-soluble portion showed an inhibitory effect on the contractile responses on rat thoracic aorta smooth muscle stimulated with KCl beforehand, while the water-soluble portion showed no effect. The chloroform-soluble portion was separated to afford a new benzochromene [orthochromene A (7)], two new isopimarane-type diterpenes [orthosiphonone A (10), orthosiphonone B (11)], and two novel migrated pimarane-type diterpenes [neoorthosiphol A (12), neoorthosiphol B (13)], together with eight known compounds (1-6, 8, 9). Among those thirteen substances, it was found that a major constituent in the water decoction of leaves, methylripariochromene A (5), exhibited a continuous decrease in systolic blood pressure after subcutaneous administration in conscious stroke-prone spontaneously hypertensive rats (SHRSP).

Animals↗
PubMed2000

Deletion of the yhhP gene results in filamentous cell morphology in Escherichia coli.

The Escherichia coli yhhP gene was predicted to encode a small hypothetical protein of 81 amino acids, the cellular function of which is not known. To gain insight into the function of this uncharacterized YhhP protein, genetic and biochemical studies were done. We first tried to express and purify the YhhP protein to prepare an anti-YhhP antiserum. Western blotting showed that the hypothetical yhhP gene is indeed transcribed and translated as a minor cytoplasmic protein. YhhP-deficient (delta yhhP) cells formed colonies poorly on a rich medium (e.g., Luria-Bertani medium) containing a relatively low concentration of NaCl, while they can grow normally either in LB containing 3% NaCl or in a synthetic medium (e.g., M9-glucose). During exponential growth in rich medium, an early step of cell division was inhibited in delta yhhP cells, forming filaments. For the YhhP-deficient filamentous cells, the FtsZ-ring formation was analyzed with immunofluorescence microscopy. The FtsZ-ring formation did not occur normally in the delta yhhP filaments, although the filamentous cells contained the FtsZ protein at a certain level comparable to that in the wild-type cells. The ftsZ gene was found to function as a multicopy suppressor of the delta yhhP mutant. Another multicopy suppressor gene was identified as the dksA gene. Provided that either the ftsZ or dksA gene was introduced into the mutant cells with its multicopy state, the resulting transformants were capable of growing in rich medium, formed wild-type short rods. These results are discussed with regard to the presumed function of this ubiquitous protein.

Amino Acid Sequence↗
PubMed2000

Difference in the meq gene between oncogenic and attenuated strains of Marek's disease virus serotype 1.

Serotype 1 strains of Marek's disease virus (MDV1), except attenuated vaccine strains, are known to cause lymphomas in visceral organs of infected chickens. To know additional genetic differences between oncogenic and nononcogenic MDV1, polymerase chain reaction (PCR) was performed to amplify the meq gene of the viral genome. In addition to the 1,062-bp band including the native meq open reading frame (ORF), a 1.2-kb band was amplified from the DNA sample prepared from chick embryo fibroblast infected with an attenuated strain, CVI988, but not with oncogenic strains. Sequence analysis of the 1.2-kb band showed that a 178-bp sequence was inserted to the meq ORF of CVI988. This ORF could encode for the Meq protein with a different transactivator domain. Southern blot analysis also confirmed the insertion of the 178-bp sequence in the meq ORF of CVI988. This insertion of 178-bp sequence may explain the reason why CVI988 is not oncogenic.

Amino Acid Sequence↗
PubMed2000

Infection of bovine immunodeficiency virus and bovine leukemia virus in water buffalo and cattle populations in Pakistan.

A survey of antibodies to bovine immunodeficiency virus (BIV) known as bovine lentivirus and bovine leukemia virus (BLV) was conducted with samples from water buffalo and cattle populations in Pakistan. A total of 370 water buffaloes and 76 cattle were tested, and 10.3% and 15.8%, respectively, were found positive for anti-BIV p26 antibodies determined by Western blotting, while 0.8% of water buffaloes and no cattle were positive for anti-BLV antibodies determined by immunodiffusion test. BIV-seropositive water buffaloes and cattle were found to have BIV proviral DNA in the peripheral blood mononuclear cells determined by nested polymerase chain reaction. This is the first report of BIV infections in water buffaloes.

Animals↗
PubMed2000

Seroprevalence of bovine immunodeficiency virus and bovine leukemia virus in draught animals in Cambodia.

Since bovine immunodeficiency virus (BIV), known as bovine lentivirus, has been detected in dairy and beef cattle in various countries around the world, a prevalence study of antibodies to BIV and bovine leukemia virus (BLV) was conducted in draught animals in five provinces in Cambodia, where protozoan parasite infections were suspected in some animals. To clarify the status of draught animals including Haryana, Brahman, mixed-breed, local breed cattle and muscle water buffaloes, a total of 544 cattle and 42 buffaloes were tested, and 26.3 and 16.7%, respectively, were found positive for anti-BIV p26 antibodies determined by Western blotting. There were 5.3% positive for anti-BLV antibodies detected by immunodiffusion test among the cattle, but no reactors among buffaloes and no dual infection for both BIV and BLV was determined in this study. Peripheral blood mononuclear cells from BIV-seropositive cattle were found to have BIV-provirus DNA, as detected by polymerase chain reaction and subsequent Southern blot hybridization. This is the first evidence for the presence of BIV and BLV infections in draught animals in tropical countries such as Cambodia. This wide distribution of BIV suggests its association with problems in animal health as reported worldwide, and that a primary BIV infection can predispose death of affected animals by other aggressive pathogens or stresses.

Animals↗
PubMed2000

Sequence analysis of the genes encoding the phosphoprotein of recent isolates of canine distemper virus in Japan.

The nucleotide sequences of the phosphoprotein (P) of canine distemper virus (CDV) strains isolated between 1992 and 1996 in Japan were determined. This is the first report of the complete sequences of the P genes of recently prevalent CDV strains. The deduced amino acid sequences of the P, C and V proteins showed that in the new Japanese isolates, these proteins have approximately 93%, 90-91% and 92% identities with those of the Onderstepoort vaccine strain, respectively. The predicted functional regions were conserved. RNA editing resulting in a shift to the open reading frame (ORF) of the V protein was shown to occur with the same efficiency in both the field isolates and vaccine strain.

Amino Acid Sequence↗
PubMed2000

The expression and cellular localization of the sperm flagellar protein MC31/CE9 in the rat testis: possible posttranscriptional regulation during rat spermiogenesis.

We isolated the MC31 cDNA clone coding the antigen specifically recognized by the monoclonal antibody mMC31, and found that MC31 was identical to rat CE9. Therefore, this molecule is called MC31/CE9. MC31/CE9, a member of the immunoglobulin superfamily molecules, was localized on the rat sperm flagellar plasma membrane. We analyzed the expression and cellular localization of MC31/CE9 mRNA and protein in the adult rat testis by use of Northern hybridization, in situ hybridization, and immunohistochemical analyses. In the course of spermatogenesis, MC31/CE9 mRNA first appeared in type B spermatogonia. The mRNA signal intensity increased progressively to pachytene spermatocytes and remained constantly at a considerable level throughout the subsequent phases of spermatocytes and round spermatids, and then decreased gradually from step-11 spermatids to disappear in step-15 spermatids. On the other hand, MC31/CE9 protein expression showed a bimodal pattern. Immunohistochemical analysis for the MC31/CE9 protein revealed its most intense immunoreactivity on the flagella of step-8 to step-19 elongated spermatids. The cytoplasmic immunoreactivity of the MC31/CE9 protein also appeared in preleptotene to early pachytene spermatocytes and elongated spermatids, with particularly intense immunoreactivity in the Golgi complexes of zygotene and early pachytene spermatocytes (stage XIII to III) as well as step-8 to step-13 spermatids. Between these two phases, the MC31/CE9 protein proved undetectable in the cytoplasm of any spermatogenic cells. Sertoli cells and Leydig cells were devoid of MC31/CE9 mRNA and its protein. Therefore, the production of MC31/CE9 is thought to be posttranscriptionally regulated during spermiogenesis.

Animals↗
PubMed2000

[A retrospective study of the length of hospitalization following allogeneic bone marrow transplantation].

To estimate the length of hospitalization following bone marrow transplantation(BMT), we conducted a retrospective study of 190 patients who had received allogeneic BMTs at our institution. By our criteria, patients were considered ready for discharge if they were afebrile, did not need intravenous chemotherapy or blood transfusions more than 2 times per week, had maintained these conditions for 1 week or more, and also had no medical history of hepatic veno-occlusive disease, grade-II-or-higher graft-versus-host disease, interstitial pneumonitis, or severe hepato-renal dysfunction. The median length of hospitalization was 108.5 days. Of 82 patients who satisfied our discharge criteria by their 70th hospital day, 10 experienced mild complications during the next 30 hospital days. Of 89 patients who were considered ready for discharge by the 40th hospital day, 30 and 38 experienced complications during the next 30 and 60 hospital days, respectively, and 16 required emergency treatment. No significant baseline characteristics distinguished the patients who experienced complications from those who did not, either after 40 or 70 hospital days. This compounded the difficulty of predicting the development of complications in patients who satisfied our discharge criteria. Although management on an outpatient basis should be safe and feasible for BMT patients who meet our discharge criteria by the 70th day of hospitalization, caution is advised for early discharges after only 40 hospital days.

Adolescent↗
PubMed2000

[Varicella-zoster virus infection after hematopoietic stem cell transplantation].

Of 264 patients aged 15 years or more who underwent hematopoietic stem cell transplantation between 1989 and September 1998 at the Tokyo Metropolitan Komagome Hospital, 47 were infected by the varicella-zoster virus (VZV). In 2 patients, visceral disease preceded cutaneous dissemination. One of these patients exhibited gastrointestinal symptoms followed by disseminated skin rash 6 days later. In the other patient, epigastralgia developed and was followed by seizures secondary to meningitis; the appearance of a skin rash 5 days after these initial symptoms yielded the diagnosis. Early diagnosis and treatment of VZV infection are important, especially for patients who present with visceral symptoms suspected to be due to VZV.

Acyclovir↗
PubMed2000

[Allogeneic bone marrow transplantation for primary myelofibrosis after splenectomy].

A 46-year-old woman was given a diagnosis of primary myelofibrosis (PMF) in 1996. Because of the progression of anemia and splenomegaly, she was scheduled for allogeneic bone marrow transplantation (BMT) from an HLA-matched sibling donor in April 1998. Cyclophosphamide and busulfan were used as the conditioning regimen. Before BMT, the patient was treated with hydroxycarbamide, which did not resolve splenomegaly. She then underwent a splenectomy, which was followed by massive portal vein thrombosis without any significant clinical outcome. After BMT, the patient obtained rapid hematologic engraftment. Moreover, the alleviation of marrow fibrosis was confirmed 4 months after BMT. We concluded that allogenic BMT can cure patients with PMF, but that the issue of splenectomy and the indications for BMT need to be evaluated further.

Bone Marrow Transplantation↗
PubMed2000

Novel mutations in the microsomal triglyceride transfer protein gene causing abetalipoproteinemia.

Abetalipoproteinemia (ABL) is an inherited disease characterized by the virtual absence of apolipoprotein B (apoB)-containing lipoproteins from plasma. Only limited numbers of families have been screened for mutations in the microsomal triglyceride transfer protein (MTP) gene. To clarify the genetic basis of clinical diversity of ABL, mutations of the MTP gene have been screened in 4 unrelated patients with ABL. Three novel mutations have been identified: a frameshift mutation caused by a single adenine deletion at position 1389 of the cDNA, and a missense mutation, Asn780Tyr, each in homozygous forms; and a splice site mutation, 2218-2A-->G, in a compound heterozygous form. The frameshift and splice site mutations are predicted to encode truncated forms of MTP. When transiently expressed in Cos-1 cells, the Asn780Tyr mutant MTP bound protein disulfide isomerase (PDI) but displayed negligible MTP activity. It is of interest that the patient having the Asn780Tyr mutation, a 27-year-old male, has none of the manifestations characteristic of classic ABL even though his plasma apoB and vitamin E were virtually undetectable. These results indicated that defects of the MTP gene are the proximal cause of ABL.

Abetalipoproteinemia↗
PubMed1999

Sterol regulatory element-binding protein-1 as a key transcription factor for nutritional induction of lipogenic enzyme genes.

To elucidate the physiological role of sterol regulatory element-binding protein-1 (SREBP-1), the hepatic mRNA levels of genes encoding various lipogenic enzymes were estimated in SREBP-1 gene knockout mice after a fasting-refeeding treatment, which is an established dietary manipulation for the induction of lipogenic enzymes. In the fasted state, the mRNA levels of all lipogenic enzymes were consistently low in both wild-type and SREBP-1(-/-) mice. However, the absence of SREBP-1 severely impaired the marked induction of hepatic mRNAs of fatty acid synthetic genes, such as acetyl-CoA carboxylase, fatty acid synthase, and stearoyl-CoA desaturase, that was observed upon refeeding in the wild-type mice. Furthermore, the refeeding responses of other lipogenic enzymes, glycerol-3-phosphate acyltransferase, ATP citrate lyase, malic enzyme, glucose-6-phosphate dehydrogenase, and S14 mRNAs, were completely abolished in SREBP-1(-/-) mice. In contrast, mRNA levels for cholesterol biosynthetic genes were elevated in the refed SREBP-1(-/-) livers accompanied by an increase in nuclear SREBP-2 protein. When fed a high carbohydrate diet for 14 days, the mRNA levels for these lipogenic enzymes were also strikingly lower in SREBP-1(-/-) mice than those in wild-type mice. These data demonstrate that SREBP-1 plays a crucial role in the induction of lipogenesis but not cholesterol biosynthesis in liver when excess energy by carbohydrates is consumed.

Acetyl-CoA Carboxylase↗
PubMed1999

A crucial role of sterol regulatory element-binding protein-1 in the regulation of lipogenic gene expression by polyunsaturated fatty acids.

Dietary polyunsaturated fatty acids (PUFA) are negative regulators of hepatic lipogenesis that exert their effects primarily at the level of transcription. Sterol regulatory element-binding proteins (SREBPs) are transcription factors responsible for the regulation of cholesterol, fatty acid, and triglyceride synthesis. In particular, SREBP-1 is known to play a crucial role in the regulation of lipogenic gene expression in the liver. To explore the possible involvement of SREBP-1 in the suppression of hepatic lipogenesis by PUFA, we challenged wild-type mice and transgenic mice overexpressing a mature form of SREBP-1 in the liver with dietary PUFA. In the liver of wild-type mice, dietary PUFA drastically decreased the mature, cleaved form of SREBP-1 protein in the nucleus, whereas the precursor, uncleaved form in the membranes was not suppressed. The decreases in mature SREBP-1 paralleled those in mRNAs for lipogenic enzymes such as fatty acid synthase and acetyl-CoA carboxylase. In the transgenic mice, dietary PUFA did not reduce the amount of transgenic SREBP-1 protein, excluding the possibility that PUFA accelerated the degradation of mature SREBP-1. The resulting sustained expression of mature SREBP-1 almost completely canceled the suppression of lipogenic gene expression by PUFA in the SREBP-1 transgenic mice. These results demonstrate that the suppressive effect of PUFA on lipogenic enzyme genes in the liver is caused by a decrease in the mature form of SREBP-1 protein, which is presumably due to the reduced cleavage of SREBP-1 precursor protein.

Animal Feed↗
PubMed1999

Increased cytosolic Ca(2+) concentration in endothelial cells by calmodulin antagonists.

Many functions of endothelial cells are Ca(2+)/calmodulin dependent, whereas the role of calmodulin in the regulation of cytosolic Ca(2+) ([Ca(2+)](i)) remains largely unexplained. In the present study, effects of various calmodulin antagonists on [Ca(2+)](i) were investigated in cultured aortic endothelial cells loaded with the Ca(2+)-sensitive dye fura-2/AM, and were compared with those of calmodulin-dependent protein kinase II (CaM kinase II) inhibitors. The calmodulin antagonists W-7, calmidazolium and fendiline provoked dose-dependent increases in [Ca(2+)](i). However, the CaM kinase II inhibitors KN-93 and lavendustin C had no effect on [Ca(2+)](i). In the absence of extracellular Ca(2+), pretreatment of cells with bradykinin (BK) and thapsigargin completely prevented W-7-stimulated increase in [Ca(2+)](i). Alternatively, pretreatment with W-7 also completely blocked BK- and thapsigargin-stimulated increases in [Ca(2+)](i). The time course of the Ca(2+)-response in W-7 treated cells was identical to that in thapsigargin-treated cells, but not that in BK-stimulated cells, suggesting that calmodulin antagonists could share a common signaling pathway with thapsigargin to increase [Ca(2+)](i) in endothelial cells. These findings indicate that calmodulin is involved in the regulation of [Ca(2+)](i), and may play an important role in the uptake of Ca(2+) to intracellular stores.

Animals↗