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K Ohshima

Publications and source records attributed to K Ohshima.

At least 271 records · Page 15Linked to original sources
PubMed1994

[The relationship between Epstein-Barr virus and metastatic lymphoepithelioma in the cervical lymph nodes, in comparison with other metastatic carcinomas and granulomatous diseases].

The nasopharyngeal lymphoepithelioma is closely related with Epstein-Barr virus. The first clinical manifestation is frequently enlargement of the cervical lymph nodes of unknown origin. The histology of the metastatic lymphoepithelioma in the lymph nodes sometimes resembles those of other metastatic carcinoma and granulomatous diseases. To differentiate the lymphoepithelioma from other disorders, we detected Epstein-Barr virus (EBV), using stamp specimens. By polymerase chain reaction, all seven lymphoepitheliomas presented amplified EBV genomes, while five of the 58 other carcinomas and eight of the 19 granulomatous diseases also did. By in situ hybridization, lymphoepitheliomas showed EBV genomes which were confined to the tumor cells, though in the other diseases they were found in the lymphocytes. Detection of EBV is very useful in making a diagnosis of lymphoepitheliomas.

Adenocarcinoma↗
PubMed1993

Molecular characterization of a short interspersed repetitive element from tobacco that exhibits sequence homology to specific tRNAs.

We have characterized a family of tRNA-derived short interspersed repetitive elements (SINEs) in the tobacco genome. Members of this family of SINEs, designated TS, have a composite structure and include a region structurally similar to a rabbit tRNA(Lys), a tRNA-unrelated region, and a TTG repeat of variable length at the 3' end. Southern blot hybridization, together with a search of the GenBank data base, showed that various plants belonging to the families Solanaceae and Convolvulaceae contain sequences homologous to the TS family in the introns and flanking regions of many genes, whereas Arabidopsis in the family Cruciferae and several species of monocoytledonous plants do not. The TS family is widely involved in structural and genetic variations in the genomes of many plants that belong to the order Tubiflorae. All of nine sequences identified in a data base search are truncated at their 5' regions and lack the tRNA-related region of the TS family. We characterized the entire sequence of the members of the TS family and found that this family can be categorized as a member of a group of SINEs with a tRNA(Lys)-like structure, as can several animal SINEs. The TS family can be divided into two major subfamilies by analysis of diagnostic positions, and one of the subfamilies is clearly younger than the other. Amplification of many copies of the full sequence of the younger subfamily occurred during the recent evolution of the tobacco lineage. We also discuss mechanisms that could be involved in the generation of SINEs in animals and also in plants.

Base Sequence↗
PubMed1993

Several short interspersed repetitive elements (SINEs) in distant species may have originated from a common ancestral retrovirus: characterization of a squid SINE and a possible mechanism for generation of tRNA-derived retroposons.

Using labeled transcripts generated in vitro from squid total genomic DNA as a probe, we isolated and characterized a SINE that is present in the squid genome. The squid SINE appears to be derived from a tRNA(Lys). When the consensus sequences of five different SINEs with a tRNA(Lys)-like structure from distantly related species, including squid, were aligned, we found in the tRNA-unrelated region two sequence motifs that were almost identical among these five SINEs. This observation suggests a common evolutionary origin for these SINEs and/or some function(s) for these motifs. Similar sequences were unexpectedly found to be present in sequences complementary to the U5 regions of several mammalian retroviruses whose primer is a tRNA(Lys). On the basis of these findings, we present a model for the generation of SINEs. We propose that they are derived from a "strong-stop DNA" with a primer tRNA(Lys) that is an intermediate in the reverse transcription of certain retroviruses. Our model suggests that a certain group of SINEs may have been generated by horizontal transmission, although it is not clear whether information was transmitted via a similar retrovirus or via an RNA or DNA of a SINE.

Animals↗
PubMed1993

Adrenalectomy and castration in the genetically obese (ob/ob) mouse.

The present studies have tested the hypothesis that adrenalectomy could modify the phenotypic expression of genetic obesity by examining the effects of adrenalectomy on the function of the gonadal system in lean and ob/ob mice. Corticosterone concentrations were undetectable in the adrenalectomized animals. Adrenalectomy significantly slowed the weight gain of obese mice in comparison to sham-adrenalectomized controls. Gonadectomy had no independent effect on weight gain. The testes, prostate, and seminal vesicles in the ob/ob mice were significantly smaller than in the lean animals. Castration lowered the weights of the prostate and seminal vesicles in the lean mice to weights close to those observed in the castrated ob/ob mice. Castration significantly increased the concentrations of LH and FSH in both ob/ob and lean mice, but the absolute concentrations were higher in the lean mice in both conditions. Adrenalectomy per se had no effect on the concentration of LH, FSH, or testosterone or on the weights of the prostate or seminal vesicles. These data indicate that adrenalectomy has no effect on the physiologic control of the reproductive system in genetically obese mice, and are consistent with the hypothesis that the defect in the ob/ob mouse is a modulator of steroid action which over expresses glucocorticoid effects and under expresses gonadal steroid effects.

Adrenal Glands↗
PubMed1993

Molecular cloning, sequencing, and expression in Escherichia coli of the potato virus Y cytoplasmic inclusion gene.

Complete nucleotide sequences of cytoplasmic inclusion (CI) genes of two strains of potato virus Y (PVY) were determined from six polymerase chain reaction (PCR)-amplified cDNA clones. The size of the CI genes of both ordinary (PVY-O) and necrotic strains (PVY-T13) was 1902 nucleotides, with a sequence homology of 83.4%. Comparison of the predicted amino acid sequences showed more than 90% homology. When these were compared with those of other potyviruses, the homology ranged from 53 to 61%. cDNAs of all or a part of the PVY-O CI gene containing an additional initiation codon (ATG) at the 5' end and a stop codon at the 3' end were constructed by PCR amplification and cloned into an Escherichia coli expression vector, pKK 223-3. Complete and truncated PVY-O CI proteins were successfully produced in E. coli as judged by reactivities with PVY-O CI protein-specific antiserum. To our knowledge, this is the first report on expression of PVY CI proteins in E. coli.

Amino Acid Sequence↗
PubMed1993

A model for the mechanism of initial generation of short interspersed elements (SINEs).

Most animal genomes contain a large number of short interspersed elements (SINEs) that have a composite structure and contain a region that is homologous to a tRNA. The majority of SINEs have been found to be derived from a tRNA(Lys), being categorized as members of a superfamily of tRNA(Lys)-related SINEs. The consensus sequences of five SINEs that belong to this superfamily were aligned. It was found that, in the tRNA-unrelated region, there are two sequence motifs that are almost identical among these five SINEs and are at a distance of 10-11 nucleotides from each other. This observation suggests a common evolutionary origin of these SINEs and/or some function(s) for these motifs. Similar sequences were unexpectedly found to be present in the sequences complementary to the U5 regions of several mammalian retroviruses whose primer is a tRNA(Lys). On the basis of these findings, we propose a possible model for the generation of SINEs whereby they are derived from a "strong stop DNA" with a primer tRNA that is an intermediate in the process of reverse transcription of certain retroviruses.

Animals↗
PubMed1993

Amplified bcl-2/JH rearrangements in reactive lymphadenopathy.

Using the polymerase chain reaction (PCR) to examine the occurrence of bcl-2/JH joining produced by t(14;18) chromosomal translocation, amplified DNA was detected in 2 of 18 lymph nodes showing reactive lymphadenopathy. The PCR was repeated in these two lymph nodes using the same DNA samples, but no amplification was detected at the second attempt. Thus the amplified DNA was considered to be derived from one copy of joined bcl-2/JH in one cell, or from a few copies in a few clonal cells with the same joined bcl-2/JH. These results suggest that false joining of bcl-2/JH at the t(14;18) junction may occur in reactive lymph nodes.

Base Sequence↗
PubMed1993

Mechanism of motilin-induced contractions in isolated perfused canine stomach.

BACKGROUND: Motilin is known to induce gastric phase III contractions via neural pathways in vivo, but the local mechanism of action is not clearly determined. METHODS: An isolated perfused canine stomach was used to demonstrate the mechanism of motilin. Synthetic canine motilin at doses of 0.1, 0.3, 1.0, and 3.0 micrograms/h was infused intra-arterially, and effects of several receptor antagonists on motilin-induced contractions were examined. RESULTS: The immunoreactive motilin concentration of venous effluent showed that motilin at doses of 0.1 and 0.3 microgram/h was within the physiological range. Each dose of motilin induced phasic contractions in the isolated stomach, and a dose-related increase in frequency was observed, but not their mean amplitude. Atropine, hexamethonium, ICS205-930, BRL43694, phentolamine, yohimbine, and propranolol significantly inhibited motilin-induced contractions. Naloxone, methysergide, and timolol did not affect the response of motilin. Prazosin significantly increased the mean amplitude of motilin-induced contractions. CONCLUSIONS: Physiological dose of motilin can initiate phasic contractions in the stomach independently of the presence of the extrinsic nerves. The results suggest that cholinergic pathway, 5-hydroxytryptamine (HT)3 receptors, and alpha receptors are involved in the motilin-induced contractions.

Animals↗
PubMed1993

Medialbasal hypothalamic deafferentation modulates feeding response to insulin in rats.

Medialbasal hypothalamic (MBH) deafferentation induces hypothalamic obesity accompanied by hyperphagia and hyperinsulinemia. Insulin is essential in developing and maintaining obesity, but the role of insulin in food intake in hypothalamic obesity is still unclear. The present study demonstrated that exogenous insulin increased food intake dose relatedly in MBH deafferented diabetic rats without developing hypoglycemia. Insulin administrations suppressed hyperphagia in the sham-operated diabetic rats. In contrast, in the MBH deafferented diabetic rats, insulin increased food intake in sow-related manner concomitant with a greater increased body weight gain than the sham-operated diabetic rats. The blood glucose levels of the MBH deafferented diabetic rats were at all time higher than those of the sham-operated diabetic rats and were hyperglycemic throughout the insulin treatment. These data indicate that insulin action on food intake mediated through the central nervous system is modulated by MBH deafferentation. This modulated insulin action may contribute to the pathogenesis on obesity in MBH deafferented animals.

Afferent Pathways↗
PubMed1993

Immunohistologic studies of Kikuchi's disease.

An immunohistologic study of lymph nodes from 21 patients with Kikuchi's disease (histiocytic necrotizing lymphadenitis) was performed. The cell components of the affected areas were mainly CD4-positive cells, CD8-positive T cells, alpha/beta T-cell gene receptor-positive T cells, and lysozyme-staining cells. CD3-positive or alpha/beta T-cell gene receptor-positive T cells were composed mainly of CD8-positive and CD11b-negative cytotoxic T cells. Double staining demonstrated that CD4-positive cells usually were positive for Ki-M1p, a marker of plasmacytoid monocytes, but negative for T-cell markers. Although some lysozyme and CD4 double-positive cells were recognized, most CD4-positive cells were negative for lysozyme. The results indicate that CD4-positive cells in the affected foci of Kikuchi's disease were mainly composed of plasmacytoid monocytes.

Adolescent↗
PubMed1993

Cytokine (interleukin-1 alpha, interleukin-1 beta, tumor necrosis factor alpha, and interleukin-6)-possessing cells in lymph nodes of malignant lymphoma.

Interleukin (IL)-1 alpha, IL-1 beta, tumor necrosis factor (TNF) alpha, and IL-6 are the most important triggers in the response of the immune system to infection and neoplasia. We examined the histochemical distribution of cytokine-possessing cells in neoplastic lymph nodes of 68 malignant lymphomas. The HLA-DR positive interdigitating reticulum cells (IRCs), histiocytes/macrophages (H/Ms) and epithelioid histiocytes with these cytokines were frequently encountered in Hodgkin's disease, B cell lymphoma of lymphoplasmacytic/cytoid, centroblastic and immunoblastic types, and T cell lymphoma of Lennert's and anaplastic large cell types. In almost all cases of B cell lymphoma of chronic lymphocytic leukemia, centrocytic, follicular centroblastic/centrocytic, Burkitt's types and T cell lymphoma of lymphoblastic, angioimmunoblastic lymphadenopathy and pleomorphic types, the cytokine-possessing cells were rarely or occasionally present. These lymphomas with less cytokines had also few or occasionally encountered IRCs, while H/Ms were frequently or occasionally present. Well-developed dendritic reticulum cells in some types of lymphoma had few cytokines. The population of cytokine-possessing cells was related with histologic type of lymphoma and the volume of IRCs. The IRCs might act as an important initiator of reactive cells against tumor cells. In addition, neoplastic T cells influenced the cytokines' possession of IRCs and H/Ms. Although lacunar, Hodgkin's and Reed-Sternberg cells in Hodgkin's disease and the neoplastic cells in peripheral T cell lymphoma showed weak positive reaction of TNF alpha in one third of the cases, lymphoma cells in the majority might have few cytokines, especially IL-1s and IL-6.

Adolescent↗
PubMed1993

Human herpesvirus-6 genomes in histiocytic necrotizing lymphadenitis (Kikuchi's disease) and other forms of lymphadenitis.

The cervical lymph nodes of 27 patients with histiocytic necrotizing lymphadenitis (HNL) were examined, as were those of 9 patients with tuberculous lymphadenitis (Tb), 10 with reactive paracortical hyperplasia (RPH), and 10 with nonspecific lymphadenitis (NSL). Southern blot analysis, the polymerase chain reaction (PCR), and in situ hybridization were use to locate the human herpesvirus-6 (HHV-6) genome. Southern blot analysis showed that all cases were negative for HHV-6 genomes, although all but one HNL case expressed HHV-6 genome using PCR. On in situ hybridization all 10 HNL cases, 6 of the 10 RPH cases, 6 of the 10 NSL cases, and 2 of the 9 Tb cases showed HHV-6 DNA. These results indicate that the presence of HHV-6 genome is not specifically related to HNL, and that this virus could hibernate in a latent form in the cervical lymph nodes. In addition, we examined three different primers (A, B, and C) for PCR amplification of HHV-6 genomes.

Adolescent↗
PubMed1993

Physiological and pathological changes in levels of the two small stress proteins, HSP27 and alpha B crystallin, in rat hindlimb muscles.

The two small stress proteins, HSP27 and alpha B crystallin, are expressed widely in normal rat tissues and abundantly in skeletal muscle. In order to clarify the physiological significance of these stress proteins, the changes in their levels were determined immunochemically, in the slow-twitch soleus muscle and fast-twitch extensor digitorum longus muscle or rectus femoris muscle of growing rats, and in those of adult rats during denervation and tenotomy. HSP27 was quantitated by specific immunoassay, similar to that for alpha B crystallin, with antibodies raised in rabbits against purified rat HSP27. In adult rats, HSP27 was present at high levels in tissues composed of striated muscle, and it was present at much higher levels in the soleus muscle than in the rectus femoris or extensor digitorum longus muscle, as is alpha B crystallin. However, in rats of perinatal age (from prenatal day 2 to postnatal day 3), levels of HSP27 in the rectus femoris muscle were enhanced like those in the soleus muscle, reaching the maximum levels at postnatal day 3. Thereafter HSP27 in the fast-twitch muscle showed a steep decrease. The increase in alpha B crystallin in the hindlimb muscles was also observed in the perinatal period. However, alpha B crystallin concentrations in the soleus muscle of perinatal rats were as low as those in rectus femoris muscle. The transection of the sciatic nerve resulted in decreases in the levels of HSP27 and alpha B crystallin in the soleus muscle of adult rats, together with increases in the levels of the two proteins in the extensor digitorum longus muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1993

Clinicopathologic, enzyme and histochemical studies of centrocytic (mantle cell) lymphoma: comparison with other types of low-grade B cell lymphoma based on the updated Kiel classification.

Lymph nodes from 21 cases of malignant lymphoma of a centrocytic (mantle cell) type, (ML, cc (mc)) were examined. All the cases had monoclonal surface immunoglobulin (sig) M and/or D, but were negative for CD10 (CALLA), and CD11c (LeuM5). Lymphoma cells with CD25 (anti-Tac)+, CD5 (Leu1)+, and alkaline phosphatase (ALPase)- in eight cases showed bone marrow involvement (10-66% of the nucleated cells; mean 32 +/- 18%) but with no leukemic changes. These eight cases had a similar phenotype and were distributed by the lymphoma cells to the examined B-chronic lymphocytic leukemia. Seven cases showed an infiltration of CD25-, CD5+, and ALPase- lymphoma cells, in which only two cases showed focal bone marrow involvement. There was a close relationship between CD25 expression and bone marrow invasion by the lymphoma cells in ML, cc (mc). Three of the six CD25- and CD5- cases presented zonal proliferation of ALPase+ lymphoma cells with round nuclei and a high anti-proliferating cell nuclear antigen/cyclin (PCNA/c) rate in the mantle zone and paracortex, accompanied by a prominent interdigitating dendritic and histiocytic cell reaction. Examined CD25-, CD5- and ALPase+ lymphoma showed a neoplastic counterpart of so-called marginal zone lymphocytes, which was different from other cases of ML, cc (mc). Lymphoma cells in ML, cc (mc), except for those of the so-called marginal zone lymphoma, might be derived from slgM+, D+/-, CD25+/-, CD5+/-, ALPase-, CD10- and CD11c- lymphocytes present in the mantle zone and primary lymph follicles.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Demonstration of the Epstein-Barr genome by the polymerase chain reaction and in situ hybridisation in a patient with viral pericarditis.

A 42 year old man admitted with effusive-constrictive pericarditis had diastolic dysfunction and pericardial thickening. Pericardiectomy was performed because of uncontrolled heart failure. The Epstein-Barr viral IgG antibody titre was exceptionally high. The EB viral genome was demonstrated in the resected pericardium by polymerase chain reaction and in situ hybridisation. EB viral pericarditis was diagnosed.

Adult↗
PubMed1993

Analysis of human herpes virus-6 genomes in lymphoid malignancy in Japan.

Ninety cases of malignant lymphoma and 56 cases of reactive lymphadenopathy were studied using Southern blot analysis and the polymerase chain reaction to identify human herpes virus-6 (HHV-6) DNA. This was detected in cases of lymphoid malignancy at a rate which ranged from 50.0% to 68.8%. There were no differences in rates for different types of lymphoid malignancies. Herpes virus-6 DNA was detected by PCR in lymphoid malignancies less frequently than in reactive lymphadenopathies. It was not detected in lymphoid malignancies using Southern blotting. These results suggest that HHV-6 DNA was not related to lymphoid malignancy and was only a latent infection of non-neoplastic cells in tumour tissue.

Base Sequence↗
PubMed1993

A histochemical study of the distribution of acetylcholinesterase-positive nerves in the goat pancreas.

The distribution of acetylcholinesterase (AChE)-positive nerve fibers in the goat pancreas was investigated with histochemical methods at the light- and electron-microscopical level. Intrapancreatic ganglia showing AChE activity were found in the interlobular connective tissue or between acini. AChE-positive nerve fibers were distributed in whole glands and formed perivascular and periinsular plexus. Terminals were identified in both the exocrine and the endocrine tissue. These observations make clear that the cholinergic system is involved in the regulation of both the exocrine and endocrine pancreas in the goat.

Acetylcholinesterase↗