Biomedical subjects

S Nakashima

Publications and source records attributed to S Nakashima.

At least 127 records · Page 7Linked to original sources

PubMed1997

Papillary adenocarcinoma of the sigmoid colon associated with psammoma bodies and hyaline globules: report of a case.

We report a case of papillary adenocarcinoma of the sigmoid colon with psammoma bodies and intracytoplasmic hyaline globules. The patient was a 59-year-old woman. The tumor showed central ulceration with smooth elevated ridges. Histologically, the tumor was composed of numerous large irregular tubular structures accompanying infolded papillary growth. The tumor cells showed cytoplasmic basophilia and prominent nuclear atypia. Psammomatous-type calcification was scattered in the tumor stroma as well as in the glandular lumina. In addition, intracytoplasmic hyaline globules of various sizes were seen in the neoplastic cells. We propose the name papillary adenocarcinoma associated with psammoma bodies and hyaline globules for this tumor. Accumulation of further cases is needed to clarify the clinical significance of this type of tumor.

Adenocarcinoma, Papillary↗

PubMed1997

Subcellular localization of the major autolysin, ATL and its processed proteins in Staphylococcus aureus.

The Staphylococcus aureus autolysin gene, atl, encodes a unique 138-kDa protein (ATL) with amidase and glucosaminidase domains. ATL has been suggested to undergo proteolytic processing to generate two extracellular peptidoglycan hydrolases, 51-kDa endo-beta-N-acetylglucosaminidase (51-kDa GL) and 62-kDa N-acetylmuramyl-L-alanine amidase (62-kDa AM). To investigate cell-associated bacteriolytic enzymes for atl gene products, proteins were extracted from the cells as follows. The cells were exposed to 3 M LiCl followed by 4% SDS. Thereafter, the cells were disrupted and again extracted with 4% SDS. Whole SDS-stable cell-associated bacteriolytic proteins were extracted without disrupting the cells. Exposure to 3 M LiCl released major 138-, 115-, 85-, 62- and 51-kDa bacteriolytic proteins, and subsequent 4% SDS extraction released major 138- and 115-kDa bacteriolytic proteins. These bacteriolytic proteins were missing in extracts of atl mutant RUSAL2 (S. aureus RN450 atl::Tn551). Immunoblotting studies suggest that these are all atl gene products: the 138-kDa protein is an ATL with a cleaved signal sequence; the 115- and 85-kDa proteins are intermediates; and the 51- and 62-kDa proteins are cell-associated 51-kDa GL and 62-kDa AM, respectively. The trypsin susceptibility of these proteins suggests that they are located outside the cell membrane. Differences in extractability and immunoelectron microscopic studies suggest that atl gene products are associated with cells in two different ways, LiCl extractable and non extractable. We suggest that the 138-kDa ATL undergoes processing through intermediate proteins (115- and 85-kDa proteins) to mature as the active cell cluster-dispersing enzymes 51-kDa GL and 62-kDa AM on the cell surface.

Amino Acid Sequence↗

PubMed1997

Cloning and characterization of the fmt gene which affects the methicillin resistance level and autolysis in the presence of triton X-100 in methicillin-resistant Staphylococcus aureus.

In methicillin-resistant Staphylococcus aureus (MRSA) strains, Triton X-100 reduced the oxacillin resistance level, although the degree of reduction varied from strain to strain. To study the responses of MRSA strains to Triton X-100, we isolated a Tn551 insertion mutant of the COL strain that became more susceptible to oxacillin in the presence of 0.02% Triton X-100. The Tn551 insertion of the mutant was transduced back to the parent strain, other MRSA strains (strains KSA8 and NCTC 10443), and methicillin-susceptible strain RN450. All transductants of MRSA strains had reduced levels of resistance to oxacillin in the presence of 0.02% Triton X-100, while those of RN450 did not. Tn551 mutants of KSA8 and NCTC 10443 also had reduced levels of resistance in the absence of 0.02% Triton X-100. The autolysis rates of the transductants in the presence of 0.02% Triton X-100 were significantly increased. Amino acid analysis of peptidoglycan and testing of heat-inactivated cells for their susceptibilities to several bacteriolytic enzymes showed that there were no significant differences between the parents and the respective Tn551 mutants. The Tn551 insertion site mapped at a location different from the previously identified fem and llm sites. Cloning and sequencing showed that Tn551 had inserted at the C-terminal region of a novel gene designated fmt. The putative Fmt protein showed a hydropathy pattern similar to that of S. aureus penicillin-binding proteins and contained two of the three conserved motifs shared by penicillin-binding proteins and beta-lactamases, suggesting that fmt may be involved in cell wall synthesis.

Bacteriolysis↗

PubMed1997

Localized perforation of the cell wall by a major autolysin: atl gene products and the onset of penicillin-induced lysis of Staphylococcus aureus.

We investigated the cell surface localization of the atl gene products of Staphylococcus aureus exposed to a lytic concentration (4 MIC) of penicillin G (PCG) by means of immunoelectron microscopy using anti-62-kDa N-acetylmuramyl-L-alanine amidase or anti-51-kDa endo-beta-N-acetylglucosaminidase immunoglobulin G. Protein A-gold conjugates reacting with antigen-antibody complex localized at sites of defects of the cell wall at the nascent cross wall. Anti-62-kDa N-acetylmuramyl-L-alanine amidase or anti-51-kDa endo-beta-N-acetylglucosaminidase immunoglobulin G inhibited the decreased turbidity caused by PCG-induced lysis and the formation of defects in the wall. The autolysis-defective mutant, S. aureus RUSAL2 (atl::Tn551), exposed to 4 MIC of PCG resisted autolysis and formation of the wall defect. These results suggest that activation or deregulation of the atl gene products at localized sites where formation of new cross wall was disturbed by PCG causes small defects in the cell wall in situ, eventually leading to general autolysis.

Antibodies↗

PubMed1997

cDNA cloning, characterization, and chromosome mapping of UBE2E2 encoding a human ubiquitin-conjugating E2 enzyme.

A cDNA encoding a human ubiquitin-conjugating enzyme (E2) with N-terminal extension (UBE2E2/UbcH8) was isolated. Amino acid sequence within the UBC domain of UBE2E2 shares over 90% identity with human UbcH6, mouse UbcM2, and Drosophila UbcD2, whereas the N-terminal region shows little amino acid sequence similarity with known proteins. The UBE2E2 gene is transcribed in various tissues as a 1.9-kb transcript. The UBE2E2 protein formed a thioester bond with ubiquitin in an E1-dependent manner, indicating that the gene product is a functional E2 enzyme. The UBE2E2 gene was assigned to human chromosome 3p24.2 by fluorescence in situ hybridization.

Amino Acid Sequence↗

PubMed1997

Molecular cloning and chromosome mapping of rat phospholipase D genes, Pld1a, Pld1b and Pld2.

We have previously obtained three partial rat phospholipase D (PLD) cDNA fragments by a reverse transcriptase-polymerase chain reaction (RT-PCR) method using degenerate primers based on two conserved amino acid sequences in PLDs of human and yeast. The entire coding regions of these genes were isolated and sequenced. The longest clone, Pld1a encodes a 1075 amino acid (aa) protein that was highly similar (89% identity) to human PLD1a, especially in four conserved regions present in other PLDs. The nucleotide sequence of the second clone was identical to that of Pld1a except that the clone lacked 114 nucleotides corresponding to 38 aa in the middle. A shorter alternatively spliced form of human PLD1 (PLD1b) lacking the corresponding 38 aa was also identified. Therefore, the second clone (Pld1b) was considered to correspond to the rat counterpart of human PLD1b. The third clone, Pld2 encoding 933 aa was smaller than that of Pld1 and its aa identity to rat Pld1 was 56%. However, it contains four conserved regions and aa sequences of these regions are homologous to those of rat Pld1 and human PLD1. Its entire aa sequence was very similar (96% identity) to the recently cloned mouse PLD, Pld2. Chromosome locations of the Pld1a, Pld1b and Pld2 genes were determined in the rat and mouse by fluorescent in situ hybridization. As expected, both Pld1a and Pld1b clones were hybridized to the same chromosome regions. The Pld1 and Pld2 genes were localized to rat chromosome 2q23.3-->q24 proximal end and the proximal region of mouse Chromosome 3B, and rat chromosome 10q23.3-->q24 proximal end and mouse Chromosome 11B3, respectively. They were mapped in regions where conserved linkage homology has been identified between the two species.

Amino Acid Sequence↗

PubMed1997

Epitope analysis of human T-cell response to MSP-1 of Plasmodium falciparum in malaria-nonexposed individuals.

BACKGROUND: MSP-1 of Plasmodium falciparum induces strong proliferative T cell responses even in malaria-nonexposed individuals. Epitopes recognized by malaria-nonimmune T cells have not been identified, and immunological mechanisms inducing such T cell responses remain to be uncovered. MSP-1 is a vaccine candidate, and it should be understood whether those epitopes have any roles in MSP-1-mediated protective immunity. The T epitopes-inducing malaria-naive T cell response was analyzed in the hope of understanding the underlying mechanisms. METHODS: Human T cell lines and clones reactive to MSP-1 of P. falciparum were established from malaria-nonexposed Japanese donors in vitro, and epitope peptides were identified. Sequences of those epitope peptides were compared to unrelated peptides in the data base. One of those peptides was tested for both binding to HLA-DR molecules and inducing proliferative responses of MSP-1-reactive T cells. RESULTS: There are at least 6 epitopes recognized by malaria-naive T cells under the restriction by HLA-DRB1*1502 or 0802. Important amino acids for the T cell recognition were identified for an MSP-1 peptide. A yeast peptide which shared those residues induced proliferative responses of MSP-1-reactive T cells. CONCLUSION: We identified T epitopes in the N-terminal region of MSP-1, some of which showed molecular similarities with unrelated environmental antigens, suggesting the presence of cross-reactive T epitopes in MSP-1. Cytokine production in response to those epitopes suggests regulatory functions of those T cells during primary infection with P. falciparum.

Amino Acid Sequence↗

PubMed1997

[Neuronal migration disorders and epilepsy].

We retrospectively studied 32 patients who had cortical dysplasia and epilepsy. Cortical dysplasia was classified into diffuse cortical dysplasia (8 patients), bilateral localized cortical dysplasia (5), unilateral diffuse cortical dysplasia (2), and focal cortical dysplasia (17). The onset of epilepsy was younger in patients with more widespread lesions. At the onset, patients with bilateral lesions generally had symptomatic generalized epilepsy, while those with unilateral cortical dysplasia tended to have symptomatic localization-related epilepsy. In patients with focal cortical dysplasia, however, 4 patients had West syndrome, either at the onset of epilepsy or during the follow up period. Seizure outcome was poor in any type of cortical dysplasia. An evaluation of prognostic factors in patients with focal cortical dysplasia did not show any of statistical significance, including gender, age at onset of epilepsy, psychomotor delay and the presence of high intensity areas in T2-weighted MRI.

Adolescent↗

PubMed1997

[Abdominal aortic surgery in Stanford type B chronic dissecting aortic aneurysm].

Three cases of a chronic type B dissecting aneurysm which required abdominal aortic reconstruction are presented. Constriction of the iliac artery due to dissection was found in case 1, in case 2 the left subclavian artery originated from a giant false lumen, and arteriosclerosis obliterans was observed in case 3. The left renal artery originated from a false lumen in all cases. Each patient underwent preliminary graft replacement of the abdominal aorta because using the femoral artery for extracorporeal circulation had a higher risk factor. The distal arch and descending aorta were then replaced with woven dacron graft. In a chronic type B dissecting aneurysm, the surgical procedure is sometimes complex because of the narrowing of the true lumen and the enlargement of the false lumen or arteries originating from the false lumen to major organs. It is necessary to consider preliminary abdominal reconstruction in cases of 1) dilatation of abdominal aneurysm, 2) obstruction, stenosis or thrombus below the abdominal aorta, or 3) presence of a giant false lumen.

Aged↗

PubMed1997

[Surgical strategy for Stanford type A aortic dissection with Marfan syndrome].

Between January 1979 and May 1996, 23 Marfan patients underwent surgeries for type A aortic dissection; 8 patients with localized type dissection and 15 with extensive type. All of the 23 patients suffered from annuloaortic ectasia (AAE) which was treated by composite graft replacement, 10 of these patients had a concomitant replacement of the aortic arch. The operative mortality rate was 8.7%, and the causes were associated with the methods of coronary artery reattachment to the graft. Of the 15 patients with the extensive type dissection, there were 11 patients who had a non-thrombotic communicating false lumen in the untreated segments of the distal dissected aorta after the first operation and from this group there were seven patients who had anastomotic leakage around the distal suture line of the graft replacement that was demonstrated by aortography. Extensive graft replacement ranging from the entire thoracic aorta to the total aorta were performed in 10 (43.5%). Late deaths occurred in three patients (13.0%) and these causes were LOS and graft infection after the second operation and prosthetic valve endcarditis 6 months after the first operation. The present data indicate that Stanford type A aortic dissection with Marfan syndrome should be undertaken on the basis of a prior achievable plan to perform an entire aortic replacement. The dissection should also be performed using a procedure which doesn't leave distal anastomotic leakage.

Adolescent↗

PubMed1997

[Simultaneous surgical treatment for distal aortic arch aneurysm associated with innominate artery aneurysm and coronary artery disease].

The patient was 69-year-old male who admitted to our hospital in November 1995 with the complaint of abnormal shadow on chest C-ray. CT scan and aortogram revealed aneurysms of the distal aortic arch and innominate artery. Seventy-five percent stenosis of the right coronary artery was also found in coronary angiogram. The total arch replacement and reconstruction of the innominate artery and CABG to right coronary artery were performed with the aid of cold blood cardioplegia and selective cerebral perfusion and open distal anastomosis. Ascending aorta was used for arterial cannulation to avoid the thromboembolism due to retrograde perfusion from the femoral artery. Satisfactory postoperative course was obtained except transient left hemiplegia and post operative three-dimensional CT scan demonstrated the successful reconstruction. The patient was doing well 8 months postoperatively.

Aged↗

PubMed1997

[Concomitant composite graft replacement of the aortic root and the aortic arch for type A aortic dissection].

Successful surgical treatment of type A aortic dissection with annuloaortic ectasia (AAE) and severely destroyed aortic root was reported. Between April 1991 and April 1996, 26 patients with type A aortic dissection underwent the surgical treatment in our institute. Among those cases, 4 cases (15%) needed the total aortic root replacement with composite graft. Two cases had Marfan syndrome and AAE and aortic regurgitation. Other two cases had severely destroyed aortic root because of the extension and advancement of the dissection to the aortic root. One was the case of disrupted right coronary ostia. And another was the case of frank rupture and massive bleeding from the aortic root during the operation. Cases of AAE were treated successfully by the routine composite graft that was made before the operation. However, the reconstruction of the aortic root for the cases who had destroyed aortic root with normal relation and size of the aortic root was cumbersome because of non displaced coronary artery ostia and the relatively narrow aortic root. For these cases, composite graft was fixed just below the aortic valve annulus by the sutures enforced with Teflon felt strip from the outside of the aorta and it made the reimplantation of the coronary ostia easier. As for the technique of the reimplantation of the coronary ostia, Carrel patch technique was used because good coaptation and fixation of the suture line around the coronary ostia could be obtained with this technique which prevent the complication such as the pseudoaneurysm or the periostial aneurysm formation around the coronary artery in the long term period. Concomitant procedures were aortic arch replacement in all cases, total arch replacement with four vessels graft in 3 cases and hemiarch replacement in 1 case. Each operations were performed with the aid of selective cerebral perfusion and open distal anastomosis.

Aged↗

PubMed1997

Persistent sciatic artery aneurysm with ruptured internal iliac artery aneurysm.

A case of aneurysm of persistent sciatic artery with ruptured aneurysm of the internal iliac artery is reported. A 62-year-old man was admitted to our hospital in emergency because of abdominal severe pain. Abdominal CT and angiography showed aneurysm of the infrarenal aortic aorta and left internal iliac artery and left persistent sciatic artery. The persistent sciatic artery aneurysm was coursed down the left thigh. Left superficial femoral artery was supplying blood to the popliteal artery as normal connection. Emergency operation was performed. The left internal iliac aneurysm was ruptured to a retroperitoneal space. The aneurysm was replaced by a Y-shaped dacron double velour graft from the infrarenal abdominal aorta to right common iliac and left external iliac arteries, which was followed by a ligation at the origin of left persistent sciatic aneurysm. The pulsation of the left lower extremity was good and additional bypass procedure to the popliteal artery was not performed. The post-operative course of the patient was excellent and post-operative angiography showed normal anatomy of the left lower extremity. Optimal management of ruptured abdominal aneurysm thus requires not only an emergency operation but detailed observation of preoperative CT and angiography in order to scrutinize the associated vascular anomalies.

Aneurysm↗

PubMed1997

[Clinical evaluation of heparin concentration and activated clotting time monitoring (HEPCON HMS) system].

The HEPCON HMS system provides both activated clotting time (ACT) and accurate whole blood heparin concentration measurements. We evaluated the impact of heparin and protamine administration using this system on the incidence and treatment of bleeding after performing a cardiopulmonary bypass. Patients were randomly divided into two groups. Heparin and protamine administration during extracorporeal circulation was determined by classical ACT management in Group A (n = 15) and by HEPCON HMS system in Group H (n = 19). There were no statistical differences in the coagulation factor, the postoperative chest tube drainage or the blood products used between the two groups. Patients in Group H received a higher dosage of heparin and a lower dosage of protamine compared with Group A. By facilitating the maintenance of a therapeutic heparin concentration and by determining an appropriate protamine dosage, the HEPCON HMS system may be useful in managing extracorporeal circulation.

Blood Coagulation Tests↗

PubMed1997

[A case of paraplegia after graft replacement of the ascending aorta and the total aortic arch for the DeBakey type I acute aortic dissection].

A rare case of paraplegia after an emergency operation for DeBakey type I acute aortic dissection was reported. The patient was a 52-year-old female who complained of severe chest and back pain. She underwent graft replacement of the ascending aorta and the total aortic arch. No neurological symptoms were observed before the operation. The cause of the paraplegia was assumed to be a thrombotic occlusion of costal arteries which originated from the false lumen.

Aortic Dissection↗

PubMed1997

[Redo operation for recurrent pulmonary artery aneurysm associated with pulmonary stenosis and regurgitation].

A 63-year-old woman who underwent surgical correction of a recurrent pulmonary artery aneurysm associated with pulmonary stenosis and regurgitation is reported. On April 1986, she underwent commissurotomy of pulmonary valve, reconstruction of right ventricle out flow tract using a Polystan monocusp patch and pulmonary aneurysmorrhaphy for pulmonary artery aneurysm. Pathological examination of the resected pulmonary arterial wall revealed mucoid degeneration of media and fragmentation of elastic fiber. Nine years after the operation, recurrence of pulmonary artery aneurysm, pulmonary stenosis and regurgitation were recognized. On September 1995, she underwent redo operation with graft replacement of pulmonary artery and pulmonary valve replacement using woven Dacron prosthesis containing a Carpentier-Edwards bioprosthetic valve. We should choose as an initial procedure with graft replacement for pulmonary artery aneurysm with fragility of the pulmonary arterial wall. She is now doing very well at one year and 5 months after the redo operation.

Aneurysm↗

PubMed1997

Synthesis and evaluation of oligonucleotides incorporating novel artificial nucleobases for the selective formation of non-natural type triplexes.

Regulation of specific gene expression by the sequence specific triplex formation has been expected as a new biological tool or a new therapeutic method in the so-called antigene strategy. As native nucleobases form triplexes only within homopurine-homopyrimidine duplexes, expansion of the target sequences to general ones has been desired. We have previously reported the selective formation of base triplets by the non-native nucleobases (1, 2) with a CG or a TA base pair, respectively, in the organic solvent. In this paper, we wish to report the synthesis of the new non-native bases (3, 4, 9-11) and their incorporation into the triplex-forming oligonucleotides (TFOs), as well as their ability of triplex formation.

Base Composition↗

PubMed1996

Bradykinin B2 receptor-induced and inositol tetrakisphosphate-evoked Ca2+ entry is sensitive to a protein tyrosine phosphorylation inhibitor in ras-transformed NIH/3T3 fibroblasts.

Signal transduction from mouse bradykinin B2 receptors to calcium influx was studied in ras-transformed NIH/3T3 (DT) fibroblasts. DT cells were preloaded with fura-2 and whole-cell voltage-clamped. Activation of B2 receptors resulted in a decrease of cellular fluorescence at the excitation wavelength of 340, or 360 nm after MnCl2 application, in both the presence and absence of external Ca2+ in DT cells, at a holding potential of -40 mV. This Mn2+ entry through the Ca2+ influx pathway increased with membrane hyperpolarization. Internal application of inositol 1,3,4,5-tetrakisphosphate (InsP4), but not of inositol 1,4,5-trisphosphate, mimicked membrane potential-dependent Mn2+ entry. Bradykinin- and InsP4-induced Ca2+ influx was blocked by 10-100 microM genistein, a tyrosine kinase inhibitor. B2 receptor activation induced time-dependent tyrosine phosphorylation of mitogen-activated protein kinase and 120 kDa protein, which was dose-dependently inhibited by genistein. Bradykinin was unable to induce Ca2+ oscillations in genistein-treated DT cells. Our results show that bradykinin-induced Ca2+ influx and oscillations depend upon protein tyrosine phosphorylation. The results suggest that two bradykinin B2 receptor-activated signal pathways, protein tyrosine phosphorylation and formation of InsP4, merge at the Ca2+ influx process in ras-transformed NIH/3T3 fibroblasts.

3T3 Cells↗