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Biomedical subjects

M Iwamura

Publications and source records attributed to M Iwamura.

At least 19 recordsLinked to original sources
PubMed2001

Anthraquinon-2-ylmethoxycarbonyl (Aqmoc): a new photochemically removable protecting group for alcohols.

[see structure]. Synthesis and photochemistry of a new photochemically removable protecting group for alcohols is described. Four carbonates of galactose derivatives (1-4) were synthesized from the corresponding arylmethanols via 4-nitrophenyl carbonate intermediates. Among them, photolysis of anthraquinon-2-ylmethoxycarbonyl (Aqmoc) galactose (1) proceeded with overall photolysis efficiency of 150 (quantum yield 0.10, and molar absorptivity 1500 M(-1) x cm(-1)) and rate constant of approximately 10(6) s(-1). To demonstrate its application to a biologically related molecule, 5'-Aqmoc-adenosine (5) was synthesized and photolyzed to yield adenosine in 91% yield.

Journal Article↗
PubMed2001

Reductive ring opening of o-nitrobenzylidene acetals of monosaccharides: synthesis and photolysis of some photolabile sugars.

[figure: see text] A 6-O-o-nitrobenzyl methylglucoside and methylmannoside were synthesized by reacting 4,6-O-o-nitrobenzylidene acetals with triethylsilane and boron trifluoride etherate. A 2,6-di-O-o-nitrobenzyl and a 3,6-di-O-o-nitrobenzyl methylmannoside were obtained from a 2,3:4,6-di-O-o-nitrobenzylidene methylmannoside by the same method. The photolabile sugars obtained were deprotected by irradiation at 350 nm to afford methylglycosides.

Benzylidene Compounds↗
PubMed2001

Retroperitoneoscopic radical nephrectomy by the posterior lumber approach for renal-cell carcinoma associated with chronic renal failure.

PURPOSE: To evaluate the efficacy and invasiveness of retroperitoneoscopic radical nephrectomy for renal-cell carcinoma (RCC) in patients with chronic renal failure (CRF), a group known to have relatively high surgical risk. PATIENTS AND METHODS: Between May 1996 and September 1999, six CRF patients maintained on hemodialysis underwent retroperitoneoscopic radical nephrectomy for clinically localized RCC by the posterior lumber approach. The excised kidneys were evacuated via a posterior skin incision (5 cm) between two port sites; the muscle layers were not incised. RESULTS: The procedure was completed in all patients with no major complications. The mean operative time was 162 (range 135-210) minutes, and the estimated blood loss was 58 (15-100) mL; none of the patients required a blood transfusion. Regular hemodialysis was restarted on postoperative day 2 or 3. CONCLUSIONS: This procedure seems to be minimally invasive and suitable for the treatment of small RCC in atrophic kidneys, especially in patients with CRF.

Atrophy↗
PubMed2001

p53 Mutation in bladder cancer patients in Japan and inhibition of growth by in vitro adenovirus-mediated wild-type p53 transduction in bladder cancer cells.

BACKGROUND: Altered expression of p53 has been described in nearly half of bladder cancers, and p53 mutations are presumed to play a role in the multistep progression of these tumors. MATERIALS AND METHODS: The incidence of mutation in the p53 gene and its correlation with histopathologic findings and patient survival were evaluated in 105 Japanese patients with bladder cancer. Laboratory experiments were also performed to confirm the infectivity and efficacy in tumor growth inhibition of an adenovirus expressing wild-type p53 in EJ bladder cancer cells. RESULTS: Mutations of p53 were observed in 38 bladder cancer specimens (36%), with a significantly higher incidence of mutation being seen in tumors of higher stage and grade. The overall survival was worse in patients with the p53 mutation. In laboratory experiments, adenoviral vectors infected bladder cancer cells in a dose- and cell density-dependent manner. The adenovirus-mediated transduction of wild-type p53 resulted in dose-dependent growth inhibition of bladder cancer cells in vitro. No significant cytotoxicity was observed after infection by a control adenovirus. CONCLUSION: Transduction of wild-type p53 might be a potential therapeutic option for bladder cancer.

Adenoviridae↗
PubMed2000

Cell-type specificity of l-leucyl l-leucine methyl ester.

l-Leucyl l-leucine methyl ester (LeuLeuOMe) is a lysosomotropic agent which is converted to a membranolytic compound by dipeptidyl peptidase I and kills human leukocytes such as CD8+ T cells and monocytes but not B cells. The reagent has also been used in mice on the assumption that the cell-type specificity to murine leukocytes is the same as that to human leukocytes. During study on the effect of LeuLeuOMe on antigen-driven IL-2 production using murine splenocytes as antigen-presenting cells, however, we noticed that murine B cells were sensitive to LeuLeuOMe. We therefore examined the cell-type specificity using murine splenocytes and peritoneal macrophages. Flow cytometric analysis revealed that the most sensitive cells to LeuLeuOMe were CD8+ cells and that CD19+ cells (B cells) were as sensitive as CD3+ cells (T cells). Murine splenic B cells, which were either positively or negatively sorted with a cell sorter, were also sensitive to LeuLeuOMe, whereas human peripheral blood B cells, which were positively sorted, were not. Peritoneal macrophages were the most insensitive to LeuLeuOMe. Thus, this study demonstrated that the cell-type specificity to murine leukocytes is different from that to human leukocytes.

Animals↗
PubMed2000

Induction of apoptosis of activated murine splenic T cells by cycloprodigiosin hydrochloride, a novel immunosuppressant.

Two types of immunosuppressants, cycloprodigiosin hydrochloride (cPrG) and L-leucyl-L-leucine methyl ester (LeuLeuOMe), both have the ability to selectively inhibit the lysosomal function, and a related compound to cPrG, prodigiosin 25-C, and LeuLeuOMe have been reported to selectively inhibit the T cell function in vitro. We therefore examined the cell-type specificity of cPrG and LeuLeuOMe using murine splenocytes. Concanavalin A (Con A)- and lentil lectin-induced proliferation was suppressed by cPrG more profoundly than lipopolysaccharide-induced proliferation. At the optimal concentration, Con A induced the proliferation of both CD4+ and CD8+ cells, whereas at a supra-optimal concentration Con A induced rather selective proliferation of CD8+ cells. Irrespective of the dose of Con A, CD4+ and CD8+ cells were equally affected by cPrG. In contrast, LeuLeuOMe induced the selective loss of CD8+ cells. cPrG enhanced the apoptosis of murine splenocytes and nylon fiber column-purified T cells cultured in the presence of Con A, as shown by the decrease in cell size and/or DNA fragmentation. Overall, this study revealed that the cell-type specificity of cPrG is different from that of LeuLeuOMe, and that the immunosuppression by cPrG is associated with apoptosis.

Animals↗
PubMed1999

Parathyroid hormone-related protein is an independent prognostic factor for renal cell carcinoma.

BACKGROUND: Parathyroid hormone-related protein (PTHrP) has been shown to be the principal cause of humoral hypercalcemia associated with renal cell carcinoma (RCC). Recent studies have demonstrated that the amino-terminal region of PTHrP has growth factor-like activities, suggesting it may play a role in the development of RCC. In this study, expression of the carboxy-terminal region of PTHrP was assessed immunohistochemically and its significance in predicting the prognosis of RCC was studied. METHODS: Forty radical nephrectomy specimens were immunostained with a murine monoclonal antibody (9H7) against the carboxy-terminal region (amino acids 109-141) of PTHrP using the streptavidin-peroxidase enzyme conjugate method. Staining intensity was evaluated semiquantitatively and compared with clinicopathologic features of the corresponding RCC. RESULTS: Immunoreactivity to 9H7 was observed to be localized to the cytosol of tumor cells at various staining intensities. There were 30 cases (75.0%) with strong staining and 10 cases (25.0%) in which staining was weak or nonexistent. Staining intensity showed no significant correlation with gender, tumor greatest dimension, stage, or grade. Tumors of the clear cell type expressed PTHrP to a significantly greater extent than tumors of the granular cell type. Tumor recurrence was significantly greater in the weakly stained or unstained group compared with the strongly stained group (P = 0.035). Multivariate analysis indicated that PTHrP expression and tumor stage were equally significant prognostic indicators in RCCs measuring <10 cm in greatest dimension. CONCLUSIONS: Evident PTHrP(109-141) expression is present in the majority of RCCs. The results of the current study indicate PTHrP(109-141) may be a possible marker of cellular differentiation and may be useful for predicting recurrence free survival in RCC patients after radical nephrectomy.

Adult↗
PubMed1999

Observations of prostate specific antigen doubling time in Japanese patients with nonmetastatic prostate carcinoma.

BACKGROUND: To understand better the natural history and biology of prostate carcinoma occurring in Japanese patients, the authors attempted to define changes with time in prostate specific antigen (PSA) measurements in 48 men with clinically resectable T1-T3 nonmetastatic disease. METHODS: The authors analyzed PSA changes prospectively in prostate carcinoma patients who were managed by watchful waiting. PSA doubling time was calculated by linear regression. These values and their distribution were compared with clinical parameters and with published series of prostate carcinoma patients. RESULTS: The mean age of the 48 patients at the time of diagnosis was 74.2 years. The median follow-up from the time of diagnosis was 24.0 months. The median PSA doubling time was 35.7 months. In 27.1% of patients, there was no increase in the PSA level over the observation period. A rapid rise in PSA (doubling time of <2 years) was observed in 29.2% of patients. These results in Japanese patients are virtually the same as those reported in Western countries. There was no statistically significant relation between calculated PSA doubling time and clinical disease stage, tumor grade, PSA level at the time of diagnosis, probability of extraprostatic disease, patient age at diagnosis, or prostate volume (P > 0.05). CONCLUSIONS: Prostate carcinoma may not differ significantly by race once it becomes clinically manifest. The magnitude of positive changes in PSA over a given period of observation may not be helpful in determining the need for therapy. The previously reported incidence of clinically insignificant prostate carcinoma, which primarily was based on pathologic findings in surgical specimens, may have been an underestimation.

Aged↗
PubMed1999

Retroperitoneoscopic adrenalectomy by a lumbodorsal approach: clinical experience with solo surgery.

Laparoscopic adrenalectomy by transperitoneal approaches necessitates the retraction of intraperitoneal organs and, hence, the creation of extra ports for retractors and assistants. The feasibility of retroperitoneoscopic adrenalectomy by a lumbodorsal approach was assessed in 26 patients with adrenal tumors. In six patients the procedure was carried out as solo surgery using the ABSOP robot camera holder, and the performance was compared with that reported for the most recent series of six cases operated upon with one human assistant. The procedures were successful in 25 patients. One patient had to be converted due to tension pneumothorax caused by diaphragmatic injury. The mean blood loss was 43.5 +/- 67.5 ml, and the procedure time averaged 144 +/- 33 min. We required an average of only 3.1 trocars to accomplish solo surgery in 5 of 6 patients (83%). The number of lens smearings decreased to one-fourth of that observed by a human assistant.

Adrenal Gland Diseases↗
PubMed1999

Limited suppression of prostate-specific antigen after salvage radiotherapy for its isolated elevation after radical prostatectomy.

OBJECTIVES: To investigate the clinical outcome and degree of prostate-specific antigen (PSA) suppression after salvage radiotherapy performed because of isolated PSA elevation after radical prostatectomy. METHODS: We examined the outcomes of 32 patients who underwent radiotherapy after radical prostatectomy. Hypersensitive, as well as conventional, PSA assays were used to measure PSA levels after irradiation. RESULTS: Of 125 patients who underwent radical prostatectomy for clinically resectable prostate cancer, 42 (33.6%) developed detectable PSA an average of 13.5 months postoperatively. Thirty-two patients underwent salvage radiotherapy. In 13 patients (40.6%), PSA became undetectable (less than 0.1 ng/mL) at a mean of 1.2 months. Two of these patients later developed detectable PSA within 1 2 months. Of 22 patients who had at least 12 months of follow-up, 8 had a durable PSA response. Of 13 patients who attained an undetectable PSA postoperatively and then showed a delayed progressive increase, 7 exhibited a durable response lasting for more than the 12 months after irradiation. By contrast, only 1 of 9 patients with persistently elevated postoperative PSA showed undetectable levels after irradiation. Frozen sera from the 8 patients with a durable response to irradiation were available to measure levels less than 0.1 ng/mL by hypersensitive assay. The mean value was 0.035 ng/mL at an average of 26.9 months after irradiation. Only 3 patients had levels less than 0.01 ng/mL. CONCLUSIONS: Although radiotherapy may be beneficial in a small number of patients, many patients continue to have measurable levels of PSA (more than 0.01 ng/mL) after irradiation. Our results suggest that this treatment in its current form is inadequate to eradicate residual carcinoma.

Aged↗
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↗
PubMed1999

Mechanism of apoptosis induced by a lysosomotropic agent, L-Leucyl-L-Leucine methyl ester.

Lysosomes are fundamental for cell growth, and thus inhibition of the lysosomal function often leads to cell death. L-Leucyl-L-leucine methyl ester (LeuLeuOMe) is a lysosomotropic agent that induces apoptosis of certain immune cells. LeuLeuOMe is taken up through receptor-mediated endocytosis, and then converted into (LeuLeu)n-OMe (n>3) by dipeptidyl peptidase I (DPPI) in lysosomes, which reportedly causes rupture of the lysosomes and DNA fragmentation. In this study we examined how lysosomal damage causes DNA fragmentation in LeuLeuOMe-treated HL-60 cells. When acridine orange was employed to monitor lysosomal membrane integrity, orange or red granular fluorescence was seen in normal cells. In contrast, LeuLeuOMe-treated cells showed orange, yellow or green cellular fluorescence all over the cytoplasm, suggesting that LeuLeuOMe induced a loss of lysosomal membrane integrity. The loss was inhibited by a DPPI inhibitor, GlyPheCHN2 (GFCHN2), but not by a caspase-3 inhibitor, Ac-DEVD-CHO, indicating that a condensation product was responsible for the loss. LeuLeuOMe also induced the activation of caspase-3-like protease and DNA fragmentation, both of which were inhibited by either GFCHN2 or Ac-DEVD-CHO. Therefore, the activation of caspase-3-like protease links the loss of lysosomal membrane integrity to DNA fragmentation during apoptosis induced by LeuLeuOMe.

Journal Article↗
PubMed1999

Efficacy and limitations of delayed/salvage radiation therapy after radical prostatectomy.

OBJECTIVE: To assess the kinetics of prostate specific antigen (PSA) and the degree of PSA suppression, to better understand the efficacy and limitations of delayed/salvage radiation therapy after radical prostatectomy. PATIENTS AND METHODS: The PSA doubling time was calculated in patients with biochemical failure after radical prostatectomy and in those who underwent delayed/salvage radiation therapy. Patients in whom PSA was undetectable by conventional assay after irradiation were followed using a hypersensitive PSA assay. RESULTS: Of 125 patients who underwent radical prostatectomy for clinically resectable prostate cancer, 47 developed biochemical failure at a mean of 11.8 months after surgery; 38 of these patients underwent radiotherapy (36 for isolated biochemical failure and two for local progression with elevated PSA levels). The mean (sd) PSA doubling time after surgery was 14.6 (16.2) months (n=44) and after radiation therapy it was 13.3 (23.9) months (n=32). Eleven of 30 evaluable patients (37%) had a sustained PSA suppression lasting at least 12 months after radiotherapy. Only the time to biochemical failure after surgery approached statistical significance for predicting a durable response to radiotherapy (P=0.08). The mean nadir value of PSA in the 11 patients with at least 12 months of sustained PSA suppression was 0.032 ng/mL at 26.9 months. CONCLUSIONS: The rapidity with which PSA levels double after surgery may provide a clinically significant indication of the nature of these recurrent tumours, which deserve the best possible attempt at cure. Slow-growing tumours with longer PSA doubling times may be better candidates for delayed/salvage radiation therapy. Larger studies involving more patients are needed to determine whether the PSA doubling time can define subgroups for which specific treatment strategies should be developed.

Aged↗
PubMed1999

Spontaneous recovery from pathologically confirmed lymphocytic adenohypophysitis with a dramatic reduction of hypophyseal size.

A pituitary mass compressing the optic nerve was revealed by magnetic resonance imaging (MRI) in a 35-year-old woman complaining of visual disturbance in the post-partum period. Responses of plasma gonadotropin and corticotropin-cortisol levels to respective hypothalamic hormones were delayed or blunted, but the response of plasma prolactin to thyrotropin-releasing hormone was exaggerated. Diabetes insipidus was not associated. Biopsy revealed lymphocytic adenohypophysitis, and no hypophysectomy was performed. Only five weeks later, the pituitary mass spontaneously disappeared on MRI. The pituitary function was normalized. Anti-thyroidal and anti-pituitary antibodies were negative throughout the clinical course. Pituitary masses developing during late pregnancy or the post-partum period should be carefully observed.

Adult↗
PubMed1999

[Indication of repeat prostatic biopsy following previous negative findings].

BACKGROUND: Many men with clinically suspicious findings would not be diagnosed to have prostate cancer. Establishing criteria for indicating repeat biopsy is imperative for early detection of prostate cancer. METHODS: Eighty-one patients underwent repeat prostatic biopsies under sonographic guidance at Kitasato University Hospital between March 1992 and October 1996. Clinicopathological parameters such as age, prostate specific antigen (PSA), PSA adjusted for transition zone volume (PSAT), PSA density (PSAD), PSA velocity, transition zone volume, prostatic volume, rectal findings, ultrasound findings and initial biopsy histology were compared with the results of repeat biopsy for searching for possible predictors of positive biopsy. RESULTS: Cancer was confirmed in 14 patients (17.3%), 10 patients by the second biopsy (15.4%, 10/65) and 4 patients by the third biopsy (28.6%, 4/14). No cancer was found at the 4th or more biopsies. Twelve (85.7%) of these patients had prostatic volume less than 40 cm3. Univariate analysis indicated PSAT, PSAD, transition zone volume and prostatic volume to be more frequent in men with positive biopsies (p < 0.05). But multivariate logistic regression analysis failed to identify any significant predictors of positive results in repeat biopsies. CONCLUSIONS: No clinicopathological parameters could reliably predict repeat biopsy findings. One or 2 additional sets of biopsies is recommended based on clinical judgement (symptoms, life expectancy, small glands < or = 40 cm3 etc.) for the purpose of early detection of prostate cancer in patients with previously negative biopsy but still with suspicious findings in consideration of approximately 20% false negative rates by the initial biopsy.

Aged↗
PubMed1999

[Histological characteristics and clinical significance of Japanese prostate cancer with low levels of prostate specific antigen of 4.0 ng/ml or lower].

PURPOSE: They set a normal limit of prostate specific antigen (PSA) to 4.0 ng/ml in Tandem R assay at most institutions. We investigated clinical and histological characteristics of prostate cancer based on whole mount step-section histology of radical prostatectomy specimens, and taking notice of Japanese prostate cancer whose levels of PSA are less than 4.0 ng/ml in normal levels. MATERIALS AND METHODS: One hundred and twenty-two patients underwent radical prostatectomy for clinically resectable prostate cancer at University Hospital from February 1992 to April 1997. Clinicopathological findings were stratified according to the preoperative PSA levels in 111 patients without preoperative endocrine therapy. Immunohistochemical study for PSA was conducted in 7 randomly selected patients. RESULTS: Of the patients 22 (19.8%) had normal (4.0 ng/ml or lower) preoperative serum PSA. Mean tumor volume in this PSA range was 1.5 cm3 with one pT 0 case included. Pathologically organ confined, potentially curable disease (< pT 3) was found in 17 (77.3%) patients and extracapsular extension and seminal vesicle invasion in 5 (23.8%), respectively. No patients had positive pelvic lymph nodes. Well differentiated tumors of Gleason scores 2-4 were found in 9 (40.9%) of the patients, moderately differentiated tumors (Gleason scores 5, 6) in 5 (22.7%) and poorly differentiated histology (Gleason scores 7-10) in 7 (31.8%). Sixteen (72.7%) patients had clinically significant tumors (> 0.5 cm3, Gleason score > or = 7). All 7 patients had positive staining for PSA, but its intensity did not correlate with serum PSA levels. CONCLUSIONS: Many prostate cancers found in surgical specimens were clinically significant despite the low levels of PSA and potentially curable by definitive treatment. Age, co-morbidity and other clinicopathological variables as well as PSA levels should all be taken into account when treatment options are discussed.

Aged↗