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Biomedical subjects

S Kyo

Publications and source records attributed to S Kyo.

At least 19 recordsLinked to original sources
PubMed1999

Expression of human telomerase subunits in ovarian malignant, borderline and benign tumors.

Telomerase activity is involved in the maintenance of telomere length and is thought to be required for cellular immortality and oncogenesis. Three major subunits composing telomerase, human telomerase RNA (hTR), telomerase-associated protein (TPI) and human telomerase catalytic subunit (hTERT), have been identified. However, their functions and the regulatory mechanisms by which telomerase is activated have not been fully determined. In the present study, a total of 35 epithelial ovarian cancers, 5 ovarian low potential malignancies (LPM), 11 ovarian benign cysts and 12 normal ovaries, as well as various cell lines derived from ovarian cancers, were examined for the expression of hTR, TPI mRNA and hTERT mRNA. Correlations of expression with telomerase activity were evaluated. Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed that hTR and TPI mRNA were expressed in more than 80% of ovarian cancers, LPM, ovarian cysts and even in normal ovaries. However, hTERT mRNA was observed only in ovarian cancers, most of which exhibited telomerase activity. Normal ovarian tissues, ovarian cysts and LPM, most of which had no telomerase activity, did not express hTERT. Five telomerase-positive ovarian cancer cell lines expressed each of the telomerase subunits, whereas 2 telomerase-negative normal primary fibroblast cell lines expressed TPI mRNA and hTR, but not hTERT mRNA. There was a significant correlation of telomerase activity with hTERT mRNA expression but not with TPI or hTR expression. Expression of hTERT is thus specific to cancer lesions and appears to be a rate-limiting determinant of the enzymatic activity of human telomerase. Up-regulation of hTERT may play a critically important role in the development of ovarian cancers.

Adenocarcinoma, Clear Cell↗
PubMed1999

Cloning of human telomerase catalytic subunit (hTERT) gene promoter and identification of proximal core promoter sequences essential for transcriptional activation in immortalized and cancer cells.

Telomerase activation is thought to be a critical step in cellular immortalization and carcinogenesis. Of the three major subunits comprising human telomerase, human telomerase catalytic subunit (hTERT) has been shown to be a rate-limiting determinant of the enzymatic activity of human telomerase. However, little is known concerning how expression of hTERT is regulated in human cells. To identify the regulatory elements controlling hTERT gene expression, approximately 3.5 kb of the 5'-flanking sequence of hTERT was cloned and characterized. The promoter of hTERT was GC rich and lacked both TATA and CAAT boxes. The CapSite Hunting method identified transcription start site 19 bp upstream of the first nucleotide of the published cDNA sequence. Transient expression assays revealed that transcription of hTERT was significantly activated in cancer cell lines but repressed in normal primary cells. Using the fibroblast lineage at various stages of transformation, we found that transcription occurred in strains that had overcome replicative senescence and expressed telomerase activity. Deletion analysis of hTERT promoter identified the 181-bp core promoter region upstream of the transcription start site. Gel shift analysis revealed two major factors binding to core promoter, an E box (CACGTG) binding factor and Sp1. Overexpression of c-Myc resulted in a significant increase in transcriptional activity of the core promoter. These findings suggest that hTERT expression is strictly regulated at the transcription machinery, and that the proximal core promoter containing an E box and Sp1 sites is required for transactivation of hTERT.

Base Sequence↗
PubMed1999

Human telomerase reverse transcriptase as a critical determinant of telomerase activity in normal and malignant endometrial tissues.

Telomerase activation is thought to be essential for cellular immortality and oncogenesis. It is observed in most malignant tumors but not in most normal somatic tissues. Normal human endometrium is, however, known to express significant telomerase activity in a menstrual phase-dependent manner. The 3 major subunits composing telomerase have been identified. Using normal and malignant endometrial tissues, we studied how these components are involved in telomerase activation. A total of 23 endometrial cancers and 32 normal human endometria in various menstrual phases as well as cell lines derived from endometrial cancer were examined for the expression of each telomerase subunit using RT-PCR analysis. Telomerase activity in each sample was determined by the TRAP assay, and the correlation between subunit expression and telomerase activity was examined. RT-PCR analysis revealed that telomerase RNA (hTR) and telomerase-associated protein (TP1) mRNA were constitutively expressed in both normal and malignant endometrial tissues. Expression of human telomerase reverse transcriptase (hTERT) mRNA was observed in most endometrial cancers, while that in normal endometrium depended on the phases of menstrual cycles. Proliferative phase normal endometria expressed hTERT mRNA, while secretory phase endometria did not. There was a strong association between telomerase activity and hTERT expression but not TP1 or hTR expression in both normal and tumor tissues. Five telomerase-positive endometrial cancer cell lines expressed each of the telomerase subunits including hTERT, while 2 telomerase-negative normal primary fibroblast cells expressed TP1 mRNA and hTR, but not hTERT mRNA. Our findings suggest that hTERT is a rate-limiting determinant of enzymatic activity of human telomerase. Since some normal tissues with high regenerative potential can express hTERT, special attention should be paid to the clinical use of hTERT inhibitors as anti-cancer drugs.

Carrier Proteins↗
PubMed1999

[Single-dose and high-volume Bretschneider cardioplegic solution for congenital heart surgery].

Bretschneider cardioplegic solution is used widely in Europe. The aim of this study is to investigate the efficacy of Bretschneider cardioplegic solution for open heart surgery of congenital heart disease in comparison with blood cardioplegia. From June 1995 to July 1997, we treated 32 congenital heart disease patients using Bretschneider cardioplegic solution and 20 patients using blood cardioplegia. Hospital mortality, water balance during operation, percentage of arrhythmia, and intubation time were not significant in both group. Also CPK and CPK-MB were not significant in both group. Bretschneider cardioplegic solution had preserved the heart as same as blood cardioplegia. This is a very convenient method so that we can use only one time infusion.

Cardiac Surgical Procedures↗
PubMed1999

[Report of three cases of emergency operation for acute pulmonary embolism].

Three successful surgical cases of acute pulmonary embolism with severe cardiopulmonary impairment were reported. Currently, thrombolysis is widely accepted as the front-line treatment for most patients with pulmonary embolism. However, treatment failure is high and can lead to death in the most severe cases. If these patients have severe cardiopulmonary impairment, pulmonary embolectomy should be done immediately.

Acute Disease↗
PubMed1999

[The effect of milrinone for the shock patients after cardiac surgery].

The effect of milrinone in the 16 postoperative shock patients of cardiovascular surgery was studied. The preoperative hemodynamic status were 12 of cardiogenic shock, 2 cases of chronic heart failure and 2 cases of unstable angina pectoris. The operative procedure were 8 cases of coronary artery bypass grafting, 4 cases of valvular surgery, 2 cases of closure of ventricular septal perforation, 2 cases of Bentall operation and 1 case of ascending aortic replacement. The postoperative hemodynamic status were 15 cases of cardiogenic shock, 10 cases of hemorrhagic shock and 1 case of septic shock. Continuous intravenous infusion of 0.5 microgram/kg/min without initial bolus loading was administered immediately after the entrance of the intensive care unit. Significant increase in the maximum blood pressure 3 hours after the infusion were observed (84 +/- 17 mmHg vs 94 +/- 12, p = 0.033). The maximum blood pressure was increased gradually until 24 hours after the infusion. Significant increase in the peripheral body temperature 3 hours after the infusion were observed (32.5 +/- 2.0 degrees C vs 35.9 +/- 1.1 degrees C, p = 0.001). The difference between the peripheral temperature and the central body temperature diminished until 24 hours after the infusion. No significant change in the central venous pressure, pulmonary arterial pressure, pulmonary and cardiac index wedge pressure were observed. No significant change in the platelet number was observed until 3 days after the infusion. Twenty patients (75%) were discharged. Four hospital deaths included 1 cardiac and 3 septic cause were seen. These data suggest that the administration of milrinone for the shock patients after cardiac surgery showed safe and that the continuous intravenous infusion of 0.5 microgram/kg/min without bolus loading showed effective for the recovery of the peripheral circulation.

Aged↗
PubMed1998

hTERT is a critical determinant of telomerase activity in renal-cell carcinoma.

Telomerase is a ribonucleoprotein enzyme which stabilizes chromosomal structure, thereby inducing cellular immortality. Three major subunits composing telomerase complex have been cloned, designated hTR (human telomerase RNA), TPI (telomerase-associated protein I), and hTERT (human telomerase reverse transcriptase). In the present study, a total of 36 renal-cell carcinomas (RCC) and adjacent normal tissues, as well as cell lines derived from RCC or normal kidney, were examined for the expression of each telomerase subunit and telomerase activity. RT-PCR analyses revealed that hTR and TP I mRNA were constitutively expressed both in tumor and in normal tissues. In contrast, hTERT mRNA was expressed in most tumors, but not in normal tissues. Telomeric-repeat-amplification-protocol (TRAP) assay revealed that more than 80% of RCC tumor tissue exhibited telomerase activity, while none of the adjacent normal tissue did. There was a significant association of telomerase activity with expression of hTERT mRNA, but not with TPI mRNA or hTR expression. Two cell lines, derived from RCC and cervical cancer, expressed telomerase activity and hTERT mRNA, while normal renal cortical epithelial cells expressed neither of them. These findings suggest that hTERT plays a critical role in determining the enzymatic activity of human telomerase, and that up-regulation of hTERT probably plays a role in the progression of human cancers.

Adult↗
PubMed1998

Expression of human telomerase subunits and correlation with telomerase activity in cervical cancer.

Activation of telomerase and stabilization of telomeres are thought to be required for both cellular immortality and oncogenesis. Three major components of human telomerase, human telomerase RNA (hTR), telomerase-associated protein (TP1/TLP1), and human telomerase catalytic subunit (hTRT/hEST2), have been identified recently. However, it remains unclear what roles these subunits play in the regulation of telomerase activity. In the present study, a total of 25 cervical cancers and 14 normal cervices as well as various cell lines derived from cervical cancer were examined for the expression of hTR, TP1 mRNA, and hTRT mRNA, and the correlations between expression of these and telomerase activity were evaluated in 23 cancers and 14 normal cervices. Reverse transcription-PCR analysis revealed that hTR and TP1 mRNA were commonly expressed in cancers and noncancerous tissues. However, hTRT mRNA was observed only in cervical cancers and cell lines, and more than 80% of cervical cancers expressed it, whereas neither normal cervical tissues nor normal primary fibroblast cells did. There was a strong correlation of telomerase activity with hTRT mRNA expression but not with TP1 or hTR expression. Cervical exfoliated cells were subjected to reverse transcription-PCR analysis for detection of hTRT mRNA, and approximately 70% of cervical cancers were positive for such expression. These findings provide strong evidence that expression of hTRT is a rate-limiting determinant of the enzymatic activity of human telomerase and that up-regulation of hTRT expression may play a critical role in human carcinogenesis. Our findings also indicate that detection of hTRT mRNA is useful for cytological screening for cervical cancer.

Carrier Proteins↗
PubMed1998

Telomerase activity in cervical cancer is quantitatively distinct from that in its precursor lesions.

Studies using the telomeric repeat amplification protocol (TRAP) assay have demonstrated telomerase activity not only in cancers but also in non-cancerous lesions. However, quantitative differences in activity between both lesions have not been examined. In the present study, using a stretch PCR assay, telomerase activity was analyzed quantitatively in cervical cancer, its precursor squamous intra-epithelial lesions (SILs) and normal cervix. In stretch PCR assay, telomerase activity was expressed in relative units vs. control activity from C33A cells (100 units). Mean telomerase activities in cervical cancer, SIL and normal cervix were 72+/-35 units, 18+/-17 units and 7+/-4 units, respectively, suggesting that telomerase activity in cancer lesions was quantitatively distinct from that in pre-malignant lesions, which may mean a much more pronounced activation of telomerase in cancers than in SIL. Our findings also suggest that stretch PCR assay can distinguish telomerase activity in cancer from that in non-cancerous lesions and may be useful for the differential diagnosis of cancer lesions.

Adenocarcinoma↗
PubMed1998

Ovarian endometrioid adenocarcinoma with ectopic production of alpha-fetoprotein.

alpha-Fetoprotein (AFP) is well known as a tumor marker of ovarian endodermal sinus tumor or embryonal carcinoma in gynecological malignancies. However, AFP production is extremely rare in ovarian epithelial cancers. Here we report a case of a 53-year-old woman with an AFP-producing ovarian endometrioid adenocarcinoma. The serum AFP level was elevated up to 2759 ng/ml preoperatively, with a subsequent decrease to the normal range after treatment. Histological examination of the tumor revealed a well-differentiated endometrioid adenocarcinoma with small foci of clear cell components. None of endodermal sinus tumor, hepatoid carcinoma, or embryonal carcinoma components were observed. Immunohistochemical analysis revealed that AFP was expressed in the cytoplasm of the endometrioid glandular lesions, but not in the clear cell components. This is probably the first case of a pure type of ovarian endometrioid adenocarcinoma with significant levels of AFP expression.

Adenocarcinoma↗
PubMed1998

[Aortic regurgitation caused by the proximal dissecting flap invagination to the left ventricle].

A 68-year-old male with sudden back pain and cardiogenic shock status transferred to our ward. Transthoracic echocardiography revealed that the abnormal round shape string was in the left ventricular outflow tract. The continuity from the staring to the aortic valve was unclear. Intimal flap could not be detected at the level of the ascending aorta. Color Doppler flow imaging showed that the severe AR jet extended into the round string. TEE showed that the intimal tear and flap was seen just above the left subclavian artery. Preoperative diagnosis was acute Stanford type A dissection and acute severe AR due to the inversion of the proximal intimal flap to the left ventricular outflow tract through the aortic valve. At operation, the proximal intimal flap was dissected circumferentially and was cut all the way around 8 cm above the aortic valve ring and was inverted to the left ventricular outflow tract. The aortic valve was preserved because of its normal character after exclusion of the proximal intimal flap. Ascending and arch replacement was carried out. Postoperative TEE and TTE slowed no findings of AR. The patient's postoperative course was uneventful. To our knowledge, this is the first reported case that severe AR caused by the proximal intimal invagination to the left ventricle.

Acute Disease↗
PubMed1998

Expression of telomerase activity in human endometrium is localized to epithelial glandular cells and regulated in a menstrual phase-dependent manner correlated with cell proliferation.

Telomerase activity is observed in most malignant tumors and germ cells, whereas normal somatic cells usually do not express it. Human endometrium is composed of glandular and stromal components and exhibits dramatic changes in proliferative activity during the menstrual cycle, which is exquisitely regulated by estrogen function. We previously reported that normal human endometrium expresses telomerase activity. However, it remains unclear which of the above components are the major sources of telomerase activity and how levels of telomerase activity are regulated over the menstrual cycle. Quantitative analysis of telomerase activity revealed that it changes dramatically over the course of the menstrual cycle and is strictly regulated in a menstrual-phase-dependent manner. Maximal activity equivalent to that in endometrial cancer was present in late proliferative phase, and minimal activity in late secretory phase. Postmenopausal endometrium and endometrium treated with anti-estrogen drugs exhibited decreased telomerase activity. Testing isolated epithelial glandular cells and stromal cells, we found that telomerase activity was localized to epithelial glandular cells. In situ RNA hybridization analysis also revealed epithelial-specific expression of human telomerase RNA. In vitro analysis of cultured epithelial cells demonstrated that telomerase activity is correlated with epithelial proliferation but not affected by estrogen treatment. These findings suggest that expression of telomerase activity is specific to epithelial cells and linked to cell proliferative status. The involvement of estrogen in telomerase regulation remains to be elucidated.

Cell Division↗
PubMed1998

Endoscopic harvest of saphenous vein graft for coronary artery bypass grafting: Saitama-Olympus technique.

OBJECTIVE: This study was undertaken to examine the clinical feasibility of a newly developed video-assisted endoscopic technique (Saitama-Olympus technique) to harvest saphenous vein graft (SVG) in 40 CABG patients. METHODS: There were 37 males and three females with an average age of 59+/-11 years. The special instruments developed were optical sheath, solid dilators, tunnel retractor, vessel dissector, GCC forceps which were utilized in conjunction with the thoracoscopic surgery system (Olympus, Tokyo, Japan). The course of the saphenous vein (SV) was marked on the skin prior to operation. SV was identified in the femoral region with a 4-cm skin incision and dissected with an open technique. The anterior surface of SV was dissected for 30 cm by the optical sheath mounted on the endoscope. Then another 4-cm skin incision above SV was placed in the popliteal region, resulting in a subcutaneous space over the SV. The subcutaneous space was then dilated and maintained with the tunnel retractor which has an endoscope channel at the top. With this system SV was visualized stably by endoscope without any assistance. All side branches were dissected and divided with the vessel dissector. When longer SVG is required, the same procedure was extended to the ankle with additional one or two skin incisions. RESULTS: SV was easily harvested in all patients with spending 15-84 min. The average number of skin incisions was 2.4+/-0.5 and the average length of the harvested SVG was 41+/-12 cm. The average number of bypassed grafts was 3.4+/-1.0 with use of left internal mammary artery (IMA) in 31 patients. The average operation time was 272+/-52 min, there were no significant prolongation relating to endoscopic SVG harvesting. The remainder of SVG in each patients was pathologically examined and there were no evidence of intimal injury. There were no major wound complications during the average follow-up of 10+/-4 months and this technique seemed to be advantageous for patients with less wound pain and better cosmetic appearance. CONCLUSIONS: The Saitama-Olympus technique to endoscopically harvest the SV is a clinically feasible surgical technique with the unique potential of a significant reduction in morbidity and decreased wound scarring in CABG patients.

Coronary Artery Bypass↗
PubMed1998

Incidence of febrile convulsions in children with congenital hypothyroidism.

Brain excitability has been inconsistently reported to be increased both in hypo- and hyperthyroidism, but there have been few studies on the effects of thyroid hormones on brain excitability in children. With this in mind, we investigated the incidence of febrile convulsions (FCs) among patients with congenital hypothyroidism, who have been taking L-thyroxine since the age of 1 month. The incidence of FCs among congenital hypothyroid patients was 1.6% (1/63) which was significantly low (p < 0.05) compared with that of normal control children who visited our hospitals as outpatients (28/341, 8.2%) and that of others (322/3301, 9.8%) investigated 33 years ago in the same area. The incidence of FC among siblings of the 63 patients (7/74, 9.5%) was not statistically different from the controls. At least 8 of the 126 parents (6.4%) had experienced FC, however, only one child was affected in the 8 families. In conclusion, it seems likely that patients with congenital hypothyroidism on regular L-T4 replacement are less prone to experience FC. More studies on the incidence of convulsive disorders in children with thyroid diseases are needed to clarify the effects of thyroid hormones on brain excitability.

Adolescent↗
PubMed1998

Quantitative differences in telomerase activity among malignant, premalignant, and benign ovarian lesions.

Telomerase activation has been demonstrated in both cancers and some noncancerous lesions. However, few studies have determined levels of telomerase activity in these lesions. In the present study, using a recently developed stretch PCR assay, telomerase activity was quantitatively determined in a variety of ovarian lesions including 36 ovarian cancers, 5 ovarian low potential malignancy (LPM) lesions, 10 ovarian cysts, and 12 normal ovaries. Telomerase activity was normalized to control activity (100 units) in C33A cell line and given in relative units. Telomerase activity in ovarian cancer (51 +/- 7 units, mean +/- SE) was significantly higher than that in LPM lesions, ovarian cysts, and normal ovaries (7 +/- 3, 10 +/- 2, and 10 +/- 2 units, respectively; P < 0.001). Interestingly, all LPMs, ovarian cysts, and normal ovaries exhibited low telomerase activity less than 30 units, and no significant difference in level of telomerase activity was found among them. We also found a significant correlation between the level of telomerase activity and the clinical stage of ovarian cancer. Our quantitative telomerase assay thus clearly distinguished telomerase activity in ovarian cancers from that in LPM lesions and ovarian cysts. Significant levels of telomerase activation frequently occurred in cancer but rarely occurred in premalignant and benign lesions, suggesting that telomerase activation is a critical step in cancer development.

Female↗
PubMed1998

[A surgical case of quadricuspid aortic valve associated aortic regurgitation and severe mitral regurgitation due to infective endocarditis].

We report a case of rare anomaly of quadricuspid aortic valve associated aortic regurgitation and severe mitral regurgitation due to infective endocarditis. A 50-year-old man was admitted to our hospital for fever and dyspnea. The transesophageal echocardiography showed severe aortic regurgitation due to four equal aortic cusps and severe mitral regurgitation due to infective endocarditis. At the operation, aortic valve and mitral valve were replaced with 23 mm and 29 mm SJM valves. His postoperative course was uneventful.

Aortic Valve↗
PubMed1998

Dispensability of p53 degradation for tumorigenicity and decreased serum requirement of human papillomavirus type 16 E6.

Certain types of human papillomavirus (HPV), such as types 16 and 18, are etiological agents for carcinogenesis of the uterine cervix. These HPVs have two oncogenes, E6 and E7, that have transforming activities in established murine cells. Tumorigenicity and decreased serum requirement for cell growth are conferred by the E6 gene, whereas anchorage-independent growth is mainly governed by the E7 gene. To understand the mechanism of cellular transformation by the HPV16 E6 gene, we examined three mutant E6 proteins defective for p53 binding, p53 degradation, or transactivation of the adenovirus E2 promoter for the ability to induce tumorigenicity and decreased serum requirement. The results showed that tumorigenicity and decreased serum requirement were associated with the ability of E6 to bind to p53, although the subsequent degradation of p53 was not required for these functions.

Animals↗