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Biomedical subjects

T Ao

Publications and source records attributed to T Ao.

At least 19 recordsLinked to original sources
PubMed2006

Optical properties in nonequilibrium phase transitions.

An open question about the dynamical behavior of materials is how phase transition occurs in highly nonequilibrium systems. One important class of study is the excitation of a solid by an ultrafast, intense laser. The preferential heating of electrons by the laser field gives rise to initial states dominated by hot electrons in a cold lattice. Using a femtosecond laser pump-probe approach, we have followed the temporal evolution of the optical properties of such a system. The results show interesting correlation to nonthermal melting and lattice disordering processes. They also reveal a liquid-plasma transition when the lattice energy density reaches a critical value.

Journal Article↗
PubMed2004

Direct observation of the saturation of stimulated Brillouin scattering by ion-trapping-induced frequency shifts.

We report the first measurement of the saturation of stimulated Brillouin scattering (SBS) by an ion-trapping-induced frequency shift, which was achieved by directly measuring the amplitude and absolute frequency of SBS-driven ion-acoustic waves (IAW). A frequency shift of up to 30% and a simultaneous saturation of driven IAW and SBS reflectivity were observed. The scaling of the frequency shift with the IAW amplitude compares well with theoretical calculations. We have further measured fast 30 ps oscillations of the SBS-driven IAW amplitude induced by the frequency shift.

Journal Article↗
PubMed2004

Single-state measurement of electrical conductivity of warm dense gold.

We report on a single-state measurement of electrical conductivity of warm dense gold in the solid to plasma transition regime. This is achieved using the idealized slab plasma approach of isochoric heating of ultrathin samples by a femtosecond laser, coupled with femtosecond probe measurements of reflectivity and transmission. The experiment also reveals the time scale associated with the disassembly of laser heated solid.

Journal Article↗
PubMed2003

Nonequilibrium and non-steady-state evolution of a shock state.

Using numerical simulations, we study the evolution of silicon in the passage of a constant-pressure shock wave launched from an adjacent pusher. We examine also its optical characteristics of reflectivity and emission. Our finding points to the study of shocked interfaces as a novel means to explore nonequilibrium, non-steady-state behaviors of shock states and an alternative approach to assess electron-ion equilibration rate in a shock wave. It also reveals important structures in such a shock wave in contrast to its usual notion as a propagating discontinuity. This offers some possibilities for reconciling the different findings on the compressibility of deuterium.

Journal Article↗
PubMed2003

Social and behavioural determinants of consistent condom use among hotel and bar workers in Northern Tanzania.

Bar and hotel workers (n=519) in Moshi, Tanzania were interviewed to obtain information about potential predictors of condom use. Samples were collected for the diagnosis of sexually transmitted diseases (STDs), including HIV. Consistent condom use was defined as always using condoms with sexual partners in the past five years. Overall consistent condom use in this population was 14.1%. In multivariate analyses, consistent condom use was inversely associated with low condom self-efficacy (adjusted odds ratio [AOR], 0.20; 95% confidence interval (CI), 0.06-0.71), low condom knowledge (AOR, 0.11; CI, 0.01-0.80), and having more than three children (AOR, 0.23; 95% CI, 0.09-0.54). Other significant predictors included perceived condom acceptability and using condoms when last exchanged sex for money or gift. These results indicate that increased specific condom knowledge, improved self-efficacy, and reduced social stigma could be effective strategies in the promotion of condom use in this population.

Adolescent↗
PubMed2001

[A case of gastrointestinal stromal tumor of rectum, difficult to differentiate from leiomyosarcoma of prostate].

A 70 year-old male was seen at the hospital with the chief complaints of frequent miction and incomplete urinary retention. A hen's egg-sized firm mass was palpable in anterior wall of rectum by digital rectal examination. Intravenous urography showed severe bilateral hydronephroureter. Transrectal ultrasound, CT scan and MRI revealed a mass with 5 cm in diameter between prostate and rectum, and the margin of them were unclear. On needle biopsy of the tumor, leiomyosarcoma of the prostate was suspected. We performed radical cytectomy and created continent urinary reserver. Because the tumor and rectum could not be lysed, part of the rectum was resected. Histological examination showed gastrointestinal stromal tumor (GIST) of rectum. GIST of rectum is a rare entity, and in case of contact with the prostate, it is difficult to differentiate from leiomyosarcoma of prostate.

Aged↗
PubMed2000

[Two cases of primary carcinoma developed in a vesical diverticulum treated with ileal neobladder for total bladder replacement].

Two cases of carcinoma developed in vesical diverticulum were encountered. Both these males, the first, 66-year-old and the second case, 68-year-old gentleman, visited our clinic with a complaint of asymptomatic gross hematuria. Total cystectomy was performed, and an ileal neobladder was constructed for total bladder replacement in both two cases. Pathological examination of the first case revealed transitional cell carcinoma, and the second case showed adenocarcinoma mixed with transitional cell carcinoma. Although primary carcinoma developed in vesical diverticulum was initially reported by Williams in 1883, adenocarcinoma is very rare. The diagnosis is often challenging and the prognosis is dire. Both our cases were successfully treated with total cystectomy and an ileal neobladder was constructed for total bladder replacement. Careful management and aggressive therapy for such patients may make even cure possible.

Adenocarcinoma↗
PubMed1999

Factors influencing morbidity in patients undergoing transurethral resection of the prostate.

OBJECTIVES: Transurethral resection of the prostate (TURP) has become the primary method to relieve bladder outlet obstruction for patients with benign prostatic hyperplasia (BPH). Data from 3861 consecutive patients with BPH who underwent TURP from 1971 to 1996 at our hospital were retrospectively analyzed. METHODS: The patients were classified into two groups comprising 1930 patients who underwent TURP from 1971 to 1985 (early group) and 1931 patients who underwent TURP from 1985 to 1996 (late group). Risk factors associated with blood transfusions and perioperative complications were analyzed in these patients. RESULTS: Mortality, morbidity, and blood transfusions were noted in 5 (0.1 %), 516 (13.4%), and 507 (13.1%) patients, respectively. The blood transfusion and morbidity rates decreased over the 25-year period (P <0.001, chi-square test for trends), which was reflected in a decrease in these rates in the late group (6.1% and 9.5%, respectively) compared with those of the early group (20.2% and 17.2%, respectively). Postoperative bleeding and morbidity were closely related to prostatic gland size and operating time. The most significant differences for the risk of a blood transfusion were related to resection time, the amount of tissue resected, age, and the decade (1970s, 1980s, or 1990s) in which the surgery was performed (P <0.0005), whereas resection time was significantly correlated with morbidity (P <0.0005). As risk factors for each complication, the time of surgical resection, the decade of surgery, and the amount of tissue resected directly correlated with the incidence of extravasation and hemostatic procedures (P < or =0.003), whereas the incidence of postoperative epididymitis positively correlated with a preoperative vasectomy and a closed drainage system (P <0.0005). CONCLUSIONS: Since the 1970s, the rates of blood transfusions and morbidity have decreased for patients undergoing TURP. Advances in techniques, instrumentation, and surgical and perioperative management, including anesthesia, have made TURP a relatively safe procedure, and it remains an effective means for treating patients with BPH.

Aged↗
PubMed1996

[Endothelin levels after extracorporeal shock waves, effects of renal function and blood pressure in rats].

BACKGROUND: Endothelin is a recently discovered peptide with strong vasoconstrictive effects which is of potential relevance in the development of renal hypertension and renal failure. It is secreted by endothelial cells in response to ischemia, endothelial lesions and inflammatory or traumatic processes. Endothelin level after extracorporeal shock waves, effects of renal function and blood pressure were examined in rats. METHODS: Changes of plasma endothelin-1 (ET-1) levels after extracorporal shock waves were studied by applying 500 shock waves to both kidneys in Wistar Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). Plasma ET-1 was measured before shock wave exposure and every thirty minutes up until 2 hours, then at 12 hours and 24 hours after shock wave exposure by specific sandwich enzyme immunoassay (EIA). Findings were then compared with those from the control group. Mean arterial pressure (MAP), glomerular filtration rate (GFR) and renal plasma flow (RPF) in rats were measured before shock wave exposure and every thirty minutes up until 2 hours after shock wave exposure, moreover made evaluation when ET-1 specific antibodies were administered intravenously into WKY and SHR. RESULTS: Plasma ET-1 was significantly increased in WKY (n = 6) and SHR (n = 7) after shock wave exposure as compared with that in the control group (p < 0.05). In SHR (n = 6), GFR temporarily decreased at 60 min but RPF remarkably decreased and renal vascular resistance (RVR) increased at 30 approximately 120 min after shock wave exposure (p < 0.05). However, infusion of ET-1 specific antibodies into SHR curbed change in those parameters, increased GFR and RPF at 60 approximately 120 min after shock wave exposure (p < 0.05). In WKY (n = 5), RPF temporarily decreased and RVR slightly increased, infusion of ET-1 specific antibodies curbed change in those parameters. MAP in SHR slightly increased at 30 min after shock wave exposure, but there was no significant change in WKY. CONCLUSION: These results suggest that plasma ET-1 levels elevated in both strains and ET-1 influenced renal function after extracorporeal shock waves, and that SHR is more sensitive to ET-1 in comparison with WKY.

Animals↗
PubMed1996

[A case of congenital penile curvature].

A case of congenital penile curvature is reported. A 21-year-old man was admitted because of penile pain curvature to the left at the erection and the difficulty of intercourse. He had no signs of Peyronie's disease and no history of penile fracture so that he was considered to have congenital penile curvature. By Nesbit's method the curvature of the penis was appropriately corrected. There were no signs of recurrence at either 1 or 5 months after the operation.

Adult↗
PubMed1995

Infrequent involvement of mutations on neurofibromatosis type 1, H-ras, K-ras and N-ras in urothelial tumors.

The neurofibromatosis type 1 (NF1) gene is considered a tumor-suppressor gene whose product acts upstream of ras. The ras gene is an oncogene very commonly detected in human cancers and consists of three families, H-ras, K-ras and N-ras. These genes are converted to active oncogenes by point mutations in codon 12, 13, or 61. Examination was made of the mutations of these genes in 39 urothelial malignant tumors (31 bladder cancer, 6 renal pelvic tumor, and 2 ureter tumors) using polymerase chain reaction single-stranded conformation polymorphism and direct sequencing methods. Three of 39 (7.7%) cases showed mobility shifts in the ras family gene but no point mutations in NF1 and N-ras genes could be detected. Mutations were found in 1 case in H-ras at codon 13 (GGT-GTT/GGT) and K-ras at codon 12 in 2 cases (GGT-GCT/GGT, GGT-GTT/GGT). All 3 cases had progressed far beyond grade 2 and stage pT2. It follows from the above that NF1 and ras gene mutations are infrequent in the pathogenesis of urothelial tumors.

Base Sequence↗
PubMed1994

[Experimental studies for immunoscintigraphy of adenocarcinoma of the prostate with 125I-labeled monoclonal antibody to gamma-seminoprotein].

We established LNCaP tumor in male nude mice after inoculation of LNCaP cells. The tumor produces the organ-specific glycoproteins in the human prostate, gamma-seminoprotein (gamma-Sm), which has been verified by immunohistochemistry and enzyme immuno assay. The LNCaP tumor is composed of 2 distinct portions, namely GEL/FLUID portion and SOLID portion. The GEL/FLUID portion contains much more gamma-Sm than the SOLID portion does. The monoclonal antibody against gamma-Sm (murine IgG1, K) was radio-labeled with iodine-125 by lactoperoxidase method followed by passage over column chromatography. Finally the conjugates with specific activity of 49.8-56.6 KBq/micrograms were obtained. Biodistribution of 125I-labeled monoclonal antibody to gamma-Sm (125I-gamma MAb) was evaluated by whole-body autoradiography (ARG) and by determination of label uptake (DLU) by the LNCaP tumor using the well type gamma counter. The ARG were obtained 1-9 days after intravenous administrations of 32-38 micrograms of 125I-gamma MAb to 12 nude mice bearing LNCaP tumor. The DLU were evaluated 3, 4 and 7 days after intravenous administrations of 18-25 micrograms of 125I-gamma MAb to 9 nude mice bearing LNCaP tumor. The DLU by organs (GEL/FLUID portion, SOLID portion, liver, kidney, spleen, lung, etc.) were expressed as F-values (%) which were calculated by the following formula: F = radioactivity per gram of tissue (dpm/g) divided by injected dose per gram of animal (dpm/g) x 100 and tissue-to-blood ratios (T/B). The specific uptake by the LNCaP tumors, especially in the GEL/FLUID portion, was observed on ARG, with optimal images of the tumor evaluated 4-7 days after administrations. The F-values and T/B of the LNCaP tumors were always higher than those of other organs. Especially T/B of GEL/FLUID portion were of 6.7 and 6.3, evaluated 4 and 7 days after administration of 125I-gamma MAb respectively. These results suggest that the radio-labeled gamma MAb is applicable for immunoscintigraphy of adenocarcinoma of the prostate.

Adenocarcinoma↗
PubMed1994

[Clinical feature and quality of life of urinary diversion patients with bladder cancer].

A clinical survey was performed on 95 cases who were treated by total cystectomy with urinary diversion at our hospital between August 1971 and March 1992. Urinary diversions were classified by ureterocutaneostomy (Group I) in 27 patients, ileal or colon conduit (Group II) in 45 and continent urinary reservoir (Group III) in 23. The patients ranged in age from 29 to 76 with an average age of 60.6 year and the male to female ratio was 68 to 27. Histopathological typing of bladder cancers showed 82 cases of transitional cell carcinoma, 8 cases of squamous cell carcinoma, 4 cases of adenocarcinoma, and 1 mixed carcinoma with transitional cell carcinoma, squamous cell carcinoma and adenocarcinoma. At present, patients alive of Group I, II and III were 14, 27 and 16, respectively, totally 57 (60.0%) patients were alive. Five-year actuarial survival rates of Group I, II and III were 45.2%, 54.1%, and 56.8%, respectively. A questionnaire survey was carried out to assess the quality of life (QOL) of 57 alive patients. The analysis of replied questionnaire showed that even all patients of each groups adapted to the basic life activities after urinary diversion, though a step forward quality of life with hobby, travel and job were decreased postoperatively in 3 groups. We obtained results that the patients of Group III were more satisfactory with daily (bath) and social life (job) than the patients of Group I, II and preoperatively. We have a new comprehension of importance of enough informed consent and mental support to the urinary diversion patients preoperatively, and of a new operative procedure not to impair the QOL.

Adenocarcinoma↗
PubMed1993

[Prognosis of incidental (stage A) prostatic cancer].

Incidentally discovered prostatic cancer can pursue a benign clinical course or it can rapidly progress. For the purpose of this study, we summarized pathological and clinical results of 107 (5.3%) stage A prostatic cancer patients in 2008 transurethral resection of the prostate for clinically diagnosed benign prostatic hyperplasia. For each patient, 3.9 slides, 13.6 tissue chips per slide and 52.5 tissue chips per patient (from 16 to 140 chips) were examined microscopically. The survival rates of patient with well, moderately and poorly differentiated groups were 62, 37 and 12% at 10 years, and those with Gleason score 2 to 4, 5 to 7 and 8 to 10 group were 63, 42 and 0% respectively. The survival rates in stage A1 (well differentiated or Gleason score 4 or less in less than 5% of the tissue removed during transurethral resection of the prostate) and stage A2 (anything other than stage A1) were 63 and 41% at 10 years, respectively. And cancer specific survival rates in stage A1 and stage A2 were 96% and 64% at 10 years, respectively. The number of cancer specific death were 1 in 30 (3.3%) in stage A1 group and 14 in 77 (18.2%) in stage A2 group. Our results indicated that tumors with low potential for aggressive behavior had a volume extent of less than 5% and a well differentiated group. Aggressive treatments should be recommended to all patients who were diagnosed stage A2 prostatic cancer.

Aged↗
PubMed1993

[An experience with a continent appendix stoma].

The submucosally embedded in situ appendix guarantees an ideal continence mechanism in patients with ileocecal urinary reservoirs. To date this modification of the Mainz pouch technique was performed successfully in 10 patients between September 1990 and October 1992. Pouch capacity ranged from 350 ml to 900 ml (mean: 565 ml), frequency of intermittent self-catheterization ranged from 3 to 7 times per day (mean: 4.4-5.4 times) and complete urinary continence without difficulty of self-catheterization was obtained in eight patients. Two patients with stomal stenosis needed to indwell a catheter. The follow up periods ranged from 3 to 24 months (mean: 14.7 months). The main advantages of appendix stoma technique are shorter operation time, a short ileal segment, no risk of nipple gliding or prolapse, no need for staples, thereby decreasing significantly the risk of stone formation, and facilitating easy catheterization. This method seemed to be valuable for continent urinary reservoir assuring patients of high quality of life.

Adenocarcinoma↗
PubMed1993

[Immunohistochemical study of the prostatic tissues with monoclonal antibody against gamma-seminoprotein. Analyses of benign prostatic hyperplasia, metastatic foci from adenocarcinoma of the prostate and malignant neoplasms other than adenocarcinoma of the prostate].

The immunohistochemical specificity of the monoclonal antibody (43-21-1-1) against gamma-seminoprotein (gamma-Sm) in the prostatic tissues was evaluated by avidin-biotin peroxidase complex method. The normal tissues of various organs, other than male genitourinary organs already examined in the previous study, the brain, skin, spinal cord, tongue, esophagus, stomach, small intestine, rectum, trachea, lung, pleura, diaphragm, liver, spleen, pancreas, mesentery, kidney, lymph node, bone, bone marrow and striated muscle were examined for control study. The prostatic tissues obtained by surgery or biopsy, benign prostatic hyperplasia (BPH; 72) urethral polyp with prostatic-type epithelium (1), bone (3) or testicular (2) metastases from adenocarcinoma of the prostate and malignant neoplasms other than adenocarcinoma of the prostate, including primary small-cell carcinoma (1), secondary embryonal carcinoma (1) and secondary mucinous adenocarcinoma (1) of the prostate were then examined. Since all but 2 (97%) specimens of BPH were obtained by transurethral resection (TUR), which might cause non-specific staining due to electro-mechanical effects, the tissue of BPH obtained by suprapubic prostatectomy were examined simultaneously, serving as a control for immunostaining. The normal tissues of various organs were never stained positively for gamma-Sm. Positive reactions of gamma Sm with this monoclonal antibody were recognized in the cytoplasms of urethral polyp with prostatic-type epithelium, bone or testicular metastases from adenocarcinoma of the prostate. The malignant neoplasms other than adenocarcinoma of the prostate examined in this study, were never stained positively. There was obviously evidence of non-specific staining in the TUR tissues of BPH.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1993

[Clinical analysis in 2266 cases of transurethral resection of the prostate].

During the past 20 years from August 1971 to July 1991, 3215 cases of transurethral resection were performed at Kitasato University Hospital, and consisted of 2008 benign prostatic hyperplasias, 692 bladder tumors, 258 prostate cancers, 167 bladder neck contractures, 38 urethral strictures, 20 chronic prostatities and 32 various urologic diseases. On 2266 transurethral resections of the prostate including 2008 benign prostatic hyperplasias, and 258 prostate cancers analysis was conducted. Patient age ranged from 44 to 97 (mean, 70.1). Resected tissue varied from 1 to 177 (mean, 26.9) grams. The time required for resection was from 9 to 245 (mean, 73.0) minutes. The volume of irrigation fluid was from 4 to 92 (mean, 25.0) liters. The duration of catheter placement after operation was 3 to 44 (mean, 4.1) days and hospitalization, 10 to 81 (mean, 12.1) days. The number of complications and blood transfusions were 308 (13.6%) and 381 (16.8%) respectively. Resected amount of tissue, volume of irrigation fluid, duration of catheter placement and frequency of complication in the benign prostatic hyperplasia group exceeded those in prostate cancer group. The length of hospitalization and blood transfusion rates were higher in the prostate cancer group. The rate or frequency of each item increased with the operating time and amount of resected tissue. Today, 60 minutes of operating time as a limiting factor of transurethral resection is not considered a important factor. Based on the results of the 2266 TURP cases, an attempt will be made to establish safer methods of treatment.

Adult↗