Biomedical subjects

S Oshima

Publications and source records attributed to S Oshima.

At least 91 records · Page 5Linked to original sources

PubMed1998

Subcellular localization of the US3 protein kinase of herpes simplex virus type 2.

One supposes that herpes simplex virus US3 gene product possessing serine/threonine protein kinase activity is a cytoplasmic enzyme. To determine its subcellular localization during viral replication we prepared an antiserum to a synthetic oligopeptide corresponding to the N-terminal region of the US3 protein of HSV type 2 strain 186. The US3 protein first appeared in the cytoplasm of infected cell at 4 h postinfection but strong fluorescence was detected in the nuclei at 8 h postinfection. At 12 h postinfection fluorescence was mainly detected in the cytoplasm, again. Further, the US3 protein expressed alone was widely distributed throughout the cell, indicating that the US3 protein by itself can be localized in the nuclei even in the absence of any other viral proteins. These observations suggest that the HSV-2 US3 protein kinase may function not only in the cytoplasm but also in the nuclei.

Amino Acid Sequence↗

PubMed1998

Characterization of the UL16 gene product of herpes simplex virus type 2.

We have raised rabbit polyclonal antisera against a His-tagged herpes simplex virus type 1 (HSV-1) UL16 fusion protein, one of which very specifically reacted with 40 kDa and 41 kDa proteins in the lysates of HSV-1 and HSV-2-infected cells, respectively. Since its reactivity to the 41 kDa protein was clearly eliminated by pre-adsorption with E. coli lysates expressing the UL16 fusion protein, the antiserum was used to characterize the UL16 products of HSV-2. The HSV-2 UL16 protein was produced at the late phase of infection in a manner highly dependent on viral DNA synthesis and was distributed in both the nuclei and the cytoplasma of infected cells. In immunofluorescence studies, the UL16-specific fluorescence in the nuclei was shown to be detected as small discrete granules. On the other hand, the cytoplasmic fluorescence was diffusely distributed around the nucleus at 8 h postinfection but, at later times of infection, it was mainly detected as a mass at a perinuclear region. The analysis on its association with capsids has revealed that the UL16 protein copurified with C capsids but not B and A capsids, and that the association with C capsids was not tight. Moreover, our experiments have shown that a detectable level of the UL16 protein was not associated with extracellular virions, and that the partially purified UL16 proteins had a DNA-binding activity. These observations are consistent with the hypothesis that the UL16 protein plays a role in capsid maturation including DNA packaging/cleavage. We have also determined the complete nucleotide sequence of the HSV-2 UL16 gene and found that a nonstandard initiation codon may be used for its translation.

Amino Acid Sequence↗

PubMed1998

Characterization of the UL4 gene product of herpes simplex virus type 2.

We have identified the herpes simplex virus type 2 (HSV-2) UL4 gene product using a rabbit polyclonal antiserum raised against a recombinant 6xHis-UL4 fusion protein expressed in Escherichia coli. The antiserum reacted specifically with a 27-kDa protein in HSV-2 186-infected cell lysates. The protein was not detectable in the presence of the viral DNA synthesis inhibitor, suggesting that the UL4 gene was expressed as a gamma 2 gene. Indirect immunofluorescence studies localized the UL4 protein within the nucleus as discrete punctate forms at late times postinfection. However, when expressed in the absence of other viral proteins, the UL4 protein was limited to the cytoplasm, indicating that an interaction with one or more other virus-induced proteins was responsible for the nuclear localization during infection. Subnuclear fractionation studies showed that the protein was released from the nuclear structure of infected cells by high salt treatment. Moreover, the UL4 protein was detected in purified virions and light particles.

Animals↗

PubMed1998

Assessing the knowledge of future internists and gynecologists in caring for a woman with tetraplegia.

OBJECTIVE: To assess the knowledge base and comfort level of potential physician "gatekeepers" when treating women with spinal cord injuries. Residents with at least 1 year of training in either internal medicine (IM) or obstetrics and gynecology (Ob/Gyn) from a large academic urban medical center were surveyed. STUDY DESIGN: This study used a written questionnaire that included a case scenario of a young woman with C6 tetraplegia who presented to her primary care physician for a routine visit. Information about the patient from her history and physical and laboratory exams was presented in stages, followed by open-ended queries to elicit information about the residents' problem-solving processes and management strategies. RESULTS: Thirty-eight percent (30 of 79) of the IM residents and 64% (14 of 22) of the Ob/Gyn residents completed the questionnaire. Significant deficits in knowledge about physical accessibility, spasticity management, and potential disability-related medical complications in pregnancy were found. More Ob/Gyn residents were aware of the risk of autonomic hyperreflexia than IM residents, whereas the IM residents demonstrated greater awareness of neurogenic bladder and skin problems. Both groups indicated they were not very comfortable in managing the patient's care. CONCLUSIONS: The results raise concern about the adequacy of the training of primary care physicians to meet the needs of people with severe disabilities.

Adult↗

PubMed1998

Characterization of the herpes simplex virus type 2 (HSV-2) US2 gene product and a US2-deficient HSV-2 mutant.

The herpes simplex virus type 2 (HSV-2) US2 gene product was identified by using a rabbit polyclonal antiserum raised against a recombinant 6 x His-US2 fusion protein expressed in Escherichia coli. The antiserum reacted specifically with a 39 kDa protein in HSV-2 strain 186-infected cell lysates. The protein was not detectable in the presence of the virus DNA synthesis inhibitor phosphonoacetic acid. Indirect immunofluorescence studies localized the US2 protein in the cytoplasm and as discrete granules at late times post-infection within and at the periphery of the nucleus, and nuclear fractionation studies showed that the protein was partially associated with the nuclear matrix of infected cells. The protein was easily detected in purified virions. Also, a US2 insertion mutant was constructed which contained an ICP6-lacZ insertion in the US2 gene. This mutant was as virulent as wild-type virus in mice when inoculated by the footpad route. The importance of the US2 protein of HSV-2 in the virus life-cycle may be apparent only in the natural human host.

Animals↗

PubMed1998

Characterization of the UL55 gene product of herpes simplex virus type 2.

We have identified the herpes simplex virus type 2 (HSV-2) UL55 gene product using a rabbit polyclonal antiserum raised against a recombinant 6 x His-UL55 fusion protein expressed in Escherichia coli. The antiserum reacted specifically with a 23 kDa protein in HSV-2 186-infected cell lysates. The protein was not detectable in the presence of the viral DNA synthesis inhibitor phosphonoacetic acid. Indirect immunofluorescence studies localized the UL55 protein within and at the periphery of the nucleus as discrete granules at late times post-infection, and nuclear fractionation studies showed that the protein was associated with the nuclear matrix of infected cells. Moreover, these discrete regions containing the UL55 protein were found to be adjacent to compartments, designated assemblons, containing the capsid protein ICP35. However, the UL55 protein was not detected in purified virions. These results suggest that the UL55 protein of HSV-2 may play an accessory role in virion assembly or maturation.

Animals↗

PubMed1998

Inhibitory effect of tomato juice on rat urinary bladder carcinogenesis after N-butyl-N-(4-hydroxybutyl)nitrosamine initiation.

The effects of tomato juice on urinary bladder carcinogenesis were studied in male Fischer 344 rats initiated with N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in rats. The animals (6 weeks old) were given 0.05% BBN in their drinking water for 8 weeks, followed by diluted tomato juice for 12 weeks, and killed at 20 weeks after the beginning of the experiment. Lycopene concentrations in the livers of rats given tomato juice were elevated. Histopathological analysis of urinary bladder lesions revealed the numbers, but not incidences, of urinary bladder transitional cell carcinomas (TCCs) to be decreased in the group given tomato juice. No influence on the incidence of simple and nodullopapillary hyperplasias, invasion or differentiation of TCC was noted. These results indicate that tomato juice, presumably the contained lycopene and other anti-oxidants in combination, exerts an inhibitory effect on the development of TCCs in the rat urinary bladder.

Animals↗

PubMed1998

Prevention of N-methylnitrosourea-induced colon carcinogenesis in F344 rats by lycopene and tomato juice rich in lycopene.

Epidemiological studies have suggested a protective effect of lycopene and lycopene-rich tomatoes against various cancers. Here, the inhibition of colon carcinogenesis by lycopene and tomato juice was investigated. Seven-week-old female F344/NSlc rats received an intrarectal dose of 2 mg (experiment I) or 4 mg (experiment II) of N-methylnitrosourea 3 times a week for 3 weeks, and had free access to one of 4 drinking fluids: plain water (control group), 17 ppm lycopene water solution (Ly group), and diluted tomato juice containing 17 ppm (Tj group) or 3.4 ppm (tj group) lycopene, throughout the experiments. The colon cancer incidence at week 35 was significantly lower in the Tj group, but not in the Ly group, than in the control group: 21% and 33% vs. 54%, in experiment I (24 rats in each group). It was significantly lower in the Tj group than in the tj and control groups, 40% vs. 72% and 84%, in experiment II (25 rats in each group). An appreciable amount of lycopene (0.02 microgram/g) was detected in the colon mucosa of rats in the Tj group, but not in the tj group. The results suggest that tomato juice rich in lycopene may have a protective effect against colon carcinogenesis.

Animals↗

PubMed1998

Simple electrocardiographic criteria for identifying the site of origin of focal right atrial tachycardia.

UNLABELLED: To construct an algorithm for identifying the precise site of origin of focal right atrial tachycardia (RAT), we analyzed the P wave configuration in 32 patients with RAT who underwent successful radiofrequency catheter ablation. The RA was divided into three areas in the left anterior oblique view: superolateral, inferolateral, and inferomedial. There were 17 RATs arising from the crista terminalis (CT-AT), 12 from the tricuspid annulus (TA-AT), and 3 from the septum away from the TA (Sep-AT). A negative P wave in lead aVR identified CT-AT with a sensitivity (sens) of 100% and a specificity (spec) of 93%. In CT-ATs, positive P waves in the inferior leads differentiated superolateral AT from inferolateral AT with a sens of 86% and a spec of 100%. In any type of AT with inferomedial or inferolateral foci, the P wave deflections in at least one of the inferior leads was negative, and negative P waves in leads V5 and V6 identified inferomedial AT with a sens of 92% and a spec of 100%. In ATs near the apex of Koch's triangle, the P wave duration in the inferior leads was shorter than during sinus rhythm. CONCLUSIONS: (1) the P wave configuration in lead aVR can easily differentiate CT-AT from TA-AT and Sep-AT; (2) the P wave configuration in the inferior leads helps to determine a superior versus inferior origin in any type of AT; (3) in inferior AT, the P wave polarity in leads V5 and V6 is useful in determining a lateral versus medial origin; (4) this algorithm can predict accurately the origin of AT.

Algorithms↗

PubMed1998

Retrograde Purkinje potential activation during sinus rhythm following catheter ablation of idiopathic left ventricular tachycardia.

We describe two patients with idiopathic left ventricular tachycardia that were cured by radiofrequency catheter ablation. Tachycardia was inducible by ventricular stimulation and was verapamil sensitive. Two distinct presystolic potentials (P1 and P2) were recorded during tachycardia in the mid-septal or inferoapical area, but only one potential (P2) was recorded during sinus rhythm. After catheter ablation at this site, the P1 potential was noted after the QRS complex during sinus rhythm, while the P2 was still observed before the QRS complex. The P1 potential showed a decremental property during atrial or ventricular pacing. These data suggest that Purkinje tissue with decremental properties was responsible for the tachycardia mechanism, and that the reentry circuit involving this tissue is likely to be of considerable size.

Anti-Arrhythmia Agents↗

PubMed1998

Verapamil-sensitive left anterior fascicular ventricular tachycardia: results of radiofrequency ablation in six patients.

INTRODUCTION: Verapamil-sensitive left ventricular tachycardia (VT) with a right bundle branch block (RBBB) configuration and left-axis deviation has been demonstrated to arise from the left posterior fascicle, and can be cured by catheter ablation guided by Purkinje potentials. Verapamil-sensitive VT with an RBBB configuration and right-axis deviation is rare, and may originate in the left anterior fascicle. METHODS AND RESULTS: Six patients (five men and one woman, mean age 54+/-15 years) with a history of sustained VT with an RBBB configuration and right-axis deviation underwent electrophysiologic study and radiofrequency (RF) ablation. VT was slowed and terminated by intravenous administration of verapamil in all six patients. Left ventricular endocardial mapping during VT identified the earliest ventricular activation in the anterolateral wall of the left ventricle in all patients. RF current delivered to this site suppressed the VT in three patients (ablation at the VT exit). The fused Purkinje potential was recorded at that site, and preceded the QRS complex by 35, 30, and 20 msec, with pace mapping showing an optimal match between the paced rhythm and the clinical VT. In the remaining three patients, RF catheter ablation at the site of the earliest ventricular activation was unsuccessful. In these three patients, Purkinje potential was recorded in the diastolic phase during VT at the mid-anterior left ventricular septum. The Purkinje potential preceded the QRS during VT by 66, 56, and 63 msec, and catheter ablation at these sites was successful (ablation at the zone of slow conduction). During 19 to 46 months of follow-up (mean 32+/-9 months), one patient in the group of ablation at the VT exit had sustained VT with a left bundle branch block configuration and an inferior axis, and one patient in the group of ablation at the zone of slow conduction experienced typical idiopathic VT with an RBBB configuration and left-axis deviation. CONCLUSION: Verapamil-sensitive VT with an RBBB configuration and right-axis deviation originates close to the anterior fascicle. RF catheter ablation can be performed successfully from the VT exit site or the zone of slow conduction where the Purkinje potential was recorded in the diastolic phase.

Adult↗

PubMed1998

Selected slow pathway ablation in a patient with corrected transposition of the great arteries and atrioventricular nodal reentrant tachycardia.

We report the first known case of AV nodal reentrant tachycardia (AVNRT) associated with a corrected transposition of the great arteries to be treated successfully by ablation of the slow pathway. Triple AV nodal pathways were observed in the anterograde direction and two types of AVNRT were induced. Input of the fast pathway to the AV node was located at the anterior portion of the left-sided AV annulus, while the input of the intermediate and slow pathways was located at the anteroseptal portion of the right-sided AV annulus. Radiofrequency energy ablation at the right anteroseptal site eliminated the intermediate and slow pathways.

Atrioventricular Node↗

PubMed1998

Angiographic evaluation of culprit lesions in acute coronary syndrome: relation to the original site on previous coronary angiography.

Culprit lesions in acute coronary syndrome [acute myocardial infarction (AMI) and unstable angina pectoris (UAP)] were examined angiographically in 222 patients who had previously undergone coronary angiography (CAG). The observation period lasted 5 years after primary CAG in medically treated patients (group M, 127 cases) and after final follow-up CAG in patients treated by percutaneous transluminal coronary angioplasty (PTCA) (group B, 95 cases). There were 33 AMIs, including 5 deaths (22/127, 17.3%, in group M vs 11/95, 11.6%, in group B; p<0.01) and 189 UAPs (105/127, 82.7%, in group M vs 84/95, 88.4%, in group B; NS). High-grade stenoses (>75%) were found in 76 (59.8%) patients in group M, of which 41 lesions (54%) resulted in acute coronary syndromes (ACSs). In group M, ACSs resulted from insignificant stenosis (< or =50%) in 67 (53%) patients and from significant stenosis (>50%) in 60 (47%) patients. In group B, ACSs resulted from insignificant stenosis in 78 (82%) patients and from significant stenosis in 17 (18%) patients. Out of 95 PTCA sites, high-grade restenosis occurred in 3 lesions and ACSs (2 AMI, 14 UAP) in 16 (16.8%). We conclude that ACSs are more likely to develop from insignificant lesions than from significant lesions. High-grade stenoses are prone to become occlusive lesions and PTCA reduces this potential risk. Most target sites of PTCA that escaped restenosis were stable in the long term.

Aged↗

PubMed1998

Improved oxygen utilization during mild exercise in heart failure.

In heart failure with low cardiac output, exercise tolerance is reduced despite modulated regional blood distribution and oxygen extraction. However, low cardiac output does not necessarily lead to reduced exercise tolerance especially during mild exercise. In the present study, in order to understand the mechanisms regulating exercise tolerance in heart failure, we measured oxygen consumption (VO2) and cardiac output (CO) during both mild and intense exercise. Patients with heart failure were divided into 2 groups; group L (n = 8) consists of patients with low anaerobic threshold (AT) < 13 ml/min per kg and group H (n = 7) consisting of patients with AT > 13 ml/min per kg. At rest, VO2 was similar between groups L and H, whereas CO was lower in group L than in group H (3.5 + 0.3 vs 4.8 + 1.4 ml/min, p < 0.01). Increase in VO2 during warm-up exercise was not significant between the 2 groups (7.4 +/- 0.5 (group L) vs 6.2 +/- 0.3 ml/min per kg (group H), ns), but increase in CO was lower in group L than in group H (2.5 +/- 0.6 vs 3.4 +/- 0.4 ml/min, p < 0.01). After warm-up to the AT point, however, the increase in not only VO2 but also CO was markedly reduced in group L than in group H (VO2: 0.5 +/- 0.4 vs 3.7 +/- 0.8 ml/min per kg, p < 0.01, CO: 0.2 +/- 0.3 vs 1.1 +/- 0.3 L/min, p < 0.01). Based on these measurements, we calculated the arteriovenous oxygen difference (c(A-V)O2 difference) during exercise in individual patients using Fick's equation. The c(A-V)O2 difference was markedly increased in severe heart failure during the warm-up stage, but between the end of warm-up and the AT point, it remained at the same level as that of group H. These results suggest the presence of a unique mechanism regulating the c(A-V)O2 difference in severe heart failure patients, activation of which may, at least during mild exercise, contribute to efficient oxygen delivery to the peripheral tissues thus compensating for the jeopardized exercise tolerance in those patients.

Aged↗

PubMed1998

Detection of K-ras gene mutations in plasma DNA of patients with pancreatic adenocarcinoma: correlation with clinicopathological features.

We investigated the presence of K-ras gene mutation in plasma DNA and assessed its clinical value in patients with pancreatic adenocarcinoma. Mutations in codon 12 of the K-ras gene were examined by mutant allele-specific amplification method using DNA extracted from surgical specimens and plasma samples of 21 patients with pancreatic adenocarcinoma. K-ras gene mutation was detected in 15 of 21 (71%) primary tumors. In 9 of 15 (60%) patients with K-ras gene mutation-positive tumors, an identical mutation was detected in the plasma DNA. None of four patients with chronic pancreatitis or five healthy subjects had such mutations in plasma DNA. Tumors positive for K-ras gene mutation in plasma DNA were significantly larger (P = 0.04) and less likely to result in a curative cure after surgical resection (P = 0.09) than those negative for the mutation. Other clinicopathological features, including age, sex, histological type, mode of invasion, and metastasis, did not correlate with K-ras gene mutations in plasma DNA. Treatment resulted in disappearance of K-ras gene mutations in plasma DNA in six of nine (67%) patients. Three patients with a persistently positive K-ras gene mutation in pre- and post-treatment plasma samples were likely to show early recurrence or have a progressive disease. Our findings suggest that K-ras gene mutation can be detected in plasma DNA of patients with pancreatic adenocarcinoma. Detection of K-ras mutations in plasma may be clinically useful for evaluating tumor burden and efficacy of treatment.

Adenocarcinoma↗

PubMed1998

Relationship between serum angiotensin-converting enzyme activity and plasma plasminogen activator inhibitor activity in patients with recent myocardial infarction.

BACKGROUND: An elevated level of angiotensin-converting enzyme (ACE) has been demonstrated to increase the risk of myocardial infarction. Plasminogen activator inhibitor (PAI) is the most important physiological inhibitor of tissue plasminogen activator in plasma. An elevated level of PAI has been reported to be associated with decreased fibrinolytic capacity and to constitute a marker of the risk for recurrent coronary thrombosis. METHODS: We measured the serum ACE activity and plasma PAI activity in 34 patients with recent myocardial infarction, and evaluated the correlation between these two values by linear regression analysis. We also administered captopril (37.5 mg/day) to 17 of these patients and placebo to the other 17 patients at random, and compared the changes in PAI activity and ACE activity in these two groups over a 1-month period. RESULTS: There was a significant correlation between the serum ACE activity and the plasma PAI activity at baseline in the patients (r = 0.498, P < 0.01). The captopril-treated patients showed significantly reduced PAI activity (P < 0.01), and a concomitant decrease in ACE activity. CONCLUSION: These results suggest that elevated ACE activity is associated with impaired fibrinolysis and that treatment with an ACE inhibitor improves the fibrinolytic function in patients with recent myocardial infarction. The results also suggest that the renin-angiotensin system plays a role in the increased risk of ischemic cardiovascular events when it is activated, and in the reduction of risk of recurrent myocardial infarction by ACE inhibition.

Adult↗

PubMed1997

Purification and characterization of the protein kinase encoded by the UL13 gene of herpes simplex virus type 2.

The proteins encoded by the UL13 genes of herpes simplex virus types 1 (HSV-1) and 2 (HSV-2) have been predicted to be protein kinases. To identify the UL13 gene product, we have raised a rabbit polyclonal antiserum against a His.Tag-HSV-1 UL13 fusion protein. The antibody specifically reacted with the 60-kDa UL13 fusion protein expressed in Escherichia coli and also recognized 56- to 57-kDa late proteins in nuclear fractions of HSV-1- and HSV-2-infected cells. On the other hand, novel casein kinase activity was induced at the late stage of infection when Vero cells were infected with HSV-1 and HSV-2. The induction of the activity was most prominent in the nuclear fractions of HSV-2-infected cells and therefore we purified the protein kinase (PK) from the nuclear extracts by successive column chromatography (phosphocellulose, DEAE-cellulose, and hydroxyapatite) using casein as an exogenous substrate. The final preparation of the enzyme contained a single major protein with an apparent molecular weight of 56 kDa which was specifically reacted with the UL13 antiserum. The PK activity was optimal in the absence of NaCl and at relatively high pH. Acidic proteins such as casein and phosvitin were efficiently phosphorylated by the PK. A basic protein, protamine, which is the best substrate for the HSV-2 US3 PK, was not detectably phosphorylated but histone was a relatively good substrate for the UL13 PK. Phosphoamino acid analysis revealed that the PK phosphorylated serine and threonine but not tyrosine. Moreover the enzyme was found to be highly resistant to heparin, a potent inhibitor of casein kinase II (CK II) and also resistant to CK I-7, a synthetic inhibitor of CK I, but very sensitive to a bioflavonoid quercetin. These results indicate that the HSV-2 UL13 PK had unique catalytic properties different from those of cellular CK I, CK II, and the viral PK encoded by the US3 gene. We have also determined the complete nucleotide sequence of the HSV-2 UL13 gene. The overall amino acid homology between the HSV-2 and HSV-1 UL13 PKs was 85.9% and the homology was highly conserved in the C-terminal region.

Amino Acid Sequence↗

PubMed1997

Pulse-spray thrombolysis in acutely obstructed coronary artery in critical situations.

Pulse-spray thrombolysis (PST) was performed to treat large coronary thrombus in 3 patients in critical situations. The originally developed pump system and a custom infusion catheter (SciMed/Boston Scientific, Maple Grove, MN) were used in combination. Case 1, a 48-yr-old male with extensive anterior myocardial infarction, failed to be recanalized by systemic thrombolysis. He underwent emergent coronary angiography, which revealed proximal occlusion of a large left anterior descending artery (LAD). TIMI 3 flow was achieved after 20 min with 200,000 units of urokinese by PST, followed by balloon angioplasty. In case 2, a 57-yr-old male, subacute stent thrombosis occurred 4 days after two and a half Palmatz-Schatz stents were implanted in mid-LAD. TIMI 3 flow was recovered at 20 min with 240,000 units of urokinese and an additional 72,000 units of rt-PA, followed by redilatation with a quarter-size larger balloon than that used in stent deployment. In case 3, a 70-yr-old male, during ultrasound study for unstable angina, a massive thrombotic complication occurred which occluded the left main trunk. PST was immediately performed under cardiac resuscitation, and the patient recovered from shock after 15 min. TIMI 3 flow was restored after 25 min. Two Palmatz-Schatz stents were implanted after thrombus completely disappeared. There were no complications, including distal embolization, intimal dissection, or bleeding. There was also no recurrence of the ischemic event. PST may be considered a potential treatment modality for coronary artery disease where large thrombus plays a major role.

Aged↗