Search PubMed⌕ Search

Biomedical subjects

Kazuhiro Suzuki

Publications and source records attributed to Kazuhiro Suzuki.

At least 73 records · Page 4Linked to original sources
PubMed2003

Free/total PSA ratio is a powerful predictor of future prostate cancer morbidity in men with initial PSA levels of 4.1 to 10.0 ng/mL.

OBJECTIVES: To evaluate the usefulness of measuring the free/total prostate-specific antigen (PSA) ratio (%fPSA) in men with initial PSA levels of 4.1 to 10.0 ng/mL as a predictor of the future risk of developing prostate cancer. METHODS: Between 1989 and 2001, 201 subjects with an initial PSA level of 4.1 to 10.0 ng/mL, who had free PSA measured at initial screening using frozen serum and underwent consecutive screening at least once, were enrolled in this study. All participants were followed up by consecutive PSA measurements. Biopsies were performed for those with PSA levels greater than 10.0 ng/mL or with a PSA velocity of 1.0 ng/mL or greater in consecutive screening. The follow-up period was 1 to 12 years, and the mean number of screenings was 3.8. The usefulness of %fPSA, age, and total PSA as predictive factors of future prostate cancer morbidity was investigated. The cumulative non-prostate cancer rate was evaluated using Kaplan-Meier analysis relative to various %fPSA cutoffs. RESULTS: A total of 142 patients (71%) underwent prostate biopsy at least once during observation according to the biopsy criteria. The detection rate of prostate cancer was 26% (53 of 201) in consecutive screening. The most recent PSA velocity and serum PSA levels at last follow-up in patients with prostate cancer were significantly higher than in those without prostate cancer. The cumulative non-prostate cancer rate was significantly greater in subjects with %fPSA less than the cutoff than in those with %fPSA at the cutoff point or greater in the %fPSA cutoffs of 16% to 25%. CONCLUSIONS: Men with PSA levels of 4.1 to 10 ng/mL who are not suspected of having prostate cancer by whatever means should undergo %fPSA measurement and be carefully monitored at short intervals over the long-term if they have lower %fPSA levels.

Aged↗
PubMed2003

Natural history of PSA increase with and without prostate cancer.

OBJECTIVES: To investigate the natural history of prostate-specific antigen (PSA) increase in men with and without prostate cancer to clarify the probability of cancer-related PSA increase. METHODS: Between 1986 and 2001, 504 men aged 79 years or younger with baseline PSA levels of 4.0 ng/mL or less and a PSA increase greater than 4.0 ng/mL on consecutive screening were enrolled in this study. The types of PSA increase were classified as "non-cancer-related PSA increase," "suspicious cancer-related PSA increase," and "cancer-related PSA increase." The probability of a "cancer-related PSA increase" was investigated and stratified by baseline PSA levels and elapsed years until the PSA level increased to greater than 4.0 ng/mL. RESULTS: The probability of a "non-cancer-related increase," "suspicious cancer-related PSA increase," and "cancer-related PSA increase" was 57%, 15%, and 28%, respectively. The PSA velocity before the PSA increase was not significantly different between those with and without prostate cancer. A "non-cancer-related PSA increase" was observed in 92% of those with a PSA increase within 2 years of baseline PSA ranges of 2.0 ng/mL or less. Regardless of elapsed years until a PSA increase to greater than 4.0 ng/mL, a "suspicious cancer-related PSA increase" or "cancer-related PSA increase" was observed in almost one half of those with baseline PSA levels of 2.1 to 4.0 ng/mL. CONCLUSIONS: Intensive serial observations should be recommended before undergoing biopsy for those with a PSA increase within 2 years of a baseline PSA range of 0.0 to 2.0 ng/mL. It may be difficult to distinguish between those with and without cancer using only subsequent total PSA measurements for the remaining cases, and prostate biopsy should be recommended at present.

Adenocarcinoma↗
PubMed2003

Hormonal and morphologic evaluation of the effects of antiandrogens on the blood supply of the rat prostate.

OBJECTIVES: To clarify the basic aspects of the regulation of the prostatic blood supply by antiandrogens, their effect on the prostatic blood supply was studied for both androgen content and morphology of true capillaries in the rat ventral prostate. The effectiveness of antiandrogens on the control of hemorrhagic status in prostatic diseases has been previously reported. METHODS: Androgen concentrations in the prostate were quantified after administration of chlormadinone acetate (CMA), finasteride, or flutamide. The prostatic blood supplies were measured after administration of CMA, finasteride, flutamide, or bicalutamide. The alpha-blockers, terazosin and tamsulosin, were included in the study as negative controls. The histologic changes in the capillaries of the ventral prostate were observed, and the luminal area was measured. RESULTS: The prostate dihydrotestosterone concentrations were decreased by the administration of all antiandrogens. Treatment with CMA, finasteride, flutamide, or bicalutamide reduced the prostatic blood supply by 50% to 65%. The parallel reduction in luminal areas of the true capillaries was observed in rats treated with CMA. Treatment with alpha-blockers did not affect the prostate androgen content, prostatic blood supply, or capillary luminal area. CONCLUSIONS: The reduction of the prostatic blood supply was suggested to be the result of a decrease in dihydrotestosterone content and the reduction in the luminal area of capillaries. The early reductive effect of antiandrogens on the prostatic blood supply suggests an alternative use for antiandrogens independent of their typical use for prostate volume regression. The results support the basic aspects of the advantage of preoperative treatment with CMA, flutamide, and bicalutamide, similar to finasteride, in reducing perioperative hemorrhage.

5-alpha Reductase Inhibitors↗
PubMed2003

CD100/Sema4D, a lymphocyte semaphorin involved in the regulation of humoral and cellular immune responses.

The semaphorin family consists of soluble and membrane-bound proteins that act as chemorepulsive factors in neuronal development, thereby playing a crucial role in axon guidance. Although they are expressed in a broad range of embryonic and adult tissues, their physiological role outside the nervous system remains to be determined. Recently, emerging evidence has suggested that several semaphorins function as part of the immune system. CD100/Sema4D is the first semaphorin family member for which a critical role in the immune response has been identified. CD100 is involved in several arms of the immune response, including humoral and cell-based immunity. This review will focus on our current understanding of the role of this immunoregulatory semaphorin.

Animals↗
PubMed2003

Bisphenol A significantly enhances the neutrophilic differentiation of promyelocytic HL-60 cells.

Bisphenol A (BPA) is a well-known endocrine disruptor. However, little information is available on its immunological effects. To investigate the effect of BPA on leukocyte differentiation, we investigated its action on the neutrophilic differentiation of HL-60 cells induced by dimethylsulfoxide and granulocyte colony-stimulating factor (G-CSF) for 6 days. At low concentrations (10(-10)-10(-8) M), BPA significantly increased the superoxide production by differentiated HL-60 cells stimulated with opsonized zymosan (OZ) by about 20%, and expression of CD18, a component of the OZ-receptor, was increased to a similar extent by 10(-9) M BPA. To investigate the effect of BPA on the activity of PU.1, a transcription factor specific for granulocytic differentiation, we established a stable clone that expressed luciferase as a reporter of PU.1 activity. PU.1 activity increased during the neutrophilic differentiation of HL-60 cells, reaching a peak on day 3 and decreasing thereafter. Nanomolar BPA augmented the PU.1 activity on day 3 by about 60%. On the other hand, tamoxifen, a competitive inhibitor of estrogen receptors, did not suppress the effect of BPA on the differentiation of HL-60 cells. These results suggest that BPA exerts an enhancing effect on the neutrophilic maturation of leukocytes through an estrogen receptor-independent pathway. Long-term exposure to BPA might significantly affect the innate immunity of mammals, even at low doses.

Benzhydryl Compounds↗
PubMed2003

Vitamin D receptor gene polymorphism in familial prostate cancer in a Japanese population.

AIM: Vitamin D acts as an antiproliferative agent against prostate cells. Epidemiological study has shown that a low level of serum vitamin D concentration is a risk factor for prostate cancer. Vitamin D acts via vitamin D receptor (VDR), and an association of genetic polymorphisms of the VDR gene has been reported. In the current study, we examined the association of VDR gene polymorphisms with familial prostate cancer in a Japanese population. METHODS: We performed a case-control study consisting of 81 familial prostate cancer cases and 105 normal control subjects. Three genetic polymorphisms (BsmI, ApaI and TaqI) in the VDR gene were examined by the restriction fragment restriction length polymorphism method. RESULTS: Overall, there was no significant association of the VDR gene polymorphisms with familial prostate cancer risk in the cases and control subjects. However, a weak association between BsmI or TaqI genotypes and cancer risk was observed in subjects under 70 years of age. Stratification of cases by clinical stage or pathological grade did not show significant association between the VDR gene polymorphisms and prostate cancer risk. CONCLUSION: In the present study, we could not confirm any significant association between VDR gene polymorphisms with familial prostate cancer risk in a Japanese population. Further large-scale case-control studies are warranted to confirm the importance of VDR gene polymorphisms in familial prostate cancer.

Adult↗
PubMed2003

Hands-free hook for endourological procedures.

We present here a hook that can be used to free both hands from holding the endoscope during endourological procedures. We made the hook from a wire hanger, and thus, it is a convenient, cheap and easy tool to make using this everyday item. As this hook makes the insertion of the endoscope into the urethra easier, it allows urologists to perform endourological procedures, which require the handling of biopsy forceps, a basket wire and lithotripsy probes, unassisted.

Cystoscopes↗
PubMed2003

Involvement of CD100, a lymphocyte semaphorin, in the activation of the human immune system via CD72: implications for the regulation of immune and inflammatory responses.

CD100/Sema4D belongs to the semaphorin family, factors known to act as repulsive cues for axons during neuronal development. Mouse CD100 plays a crucial role in both humoral and cellular immunity through ligation of the lymphocyte receptor, CD72. It remains controversial, however, whether human CD100 can function through human CD72 in a manner similar to mouse CD100. To determine the function of human CD100, we generated a recombinant soluble human CD100 protein comprised of the extracellular region of human CD100 fused to the human IgG1 Fc region (hCD100-Fc). hCD100-Fc specifically binds to cells expressing human CD72. As observed previously in the mouse, hCD100-Fc induces the tyrosine dephosphorylation of human CD72, leading to the dissociation of SHP-1 from the CD72 cytoplasmic tail. Consistent with findings for mouse CD100, hCD100-Fc exerts a co-stimulatory effect on B cells and dendritic cells that are stimulated with anti-CD40 mAb. Furthermore, both hCD100-Fc and anti-human CD72 agonistic mAb induce the production of the pro-inflammatory cytokines tumor necrosis factor-alpha, IL-6 and IL-8, even in the absence of anti-CD40 mAb. Collectively, our findings not only demonstrate that human CD100, interacting with human CD72, can function as a ligand in a manner similar to mouse CD100, but also suggest the involvement of human CD100 in inflammatory responses.

Animals↗
PubMed2003

Possible involvement of optimally phosphorylated L-plastin in activation of superoxide-generating NADPH oxidase.

The involvement of protein phosphatases in the activation of superoxide (O2-)- generating enzyme in human neutrophils was examined using calyculin A, an inhibitor of protein phosphatase type 1 and 2A. Calyculin A inhibited the phorbol myristate acetate (PMA)- and opsonized zymosan (OZ)-activated O2- generation by human neutrophils. This inhibitory effect of calyculin A on PMA-activated O2- generation was reversed by the addition of KT5926, a specific inhibitor of myosin light chain kinase and Ca2+/calmodulin-dependent protein kinase II. These results suggest that the addition of calyculin A may cause hyperphosphorylation of some protein(s) that plays a crucial role in the PMA-dependent activation of O2- generating enzyme, and that this protein hyperphosphorylation may be evoked by a KT5926-sensitive kinase or its downstream kinase. Whereas two-dimensional analysis involving 32P revealed that calyculin A caused the hyperphosphorylation of many proteins, KT5926 mainly reduced the calyculin A-induced hyperphosphorylation of a 67 kDa protein in activated neutrophils, suggesting that the hyperphosphorylation of the 67 kDa protein might inhibit the PMA-dependent activation of NADPH oxidase. The 67 kDa cytosolic protein was moderately phosphorylated on the addition of PMA. On the other hand, in the absence of calyculin A, KT5926 inhibited both PMA-induced O2- generation and phosphorylation of the 67 kDa protein. Amino acid sequence analysis of peptides derived from the 67 kDa protein revealed that the 67 kDa protein was identical to L-plastin, an actin-bundling protein. We conclude that optimally phosphorylated L-plastin may play some crucial role in the activation of NADPH oxidase.

Amino Acid Sequence↗
PubMed2003

Cryptococcus neoformans induces alterations in the cytoskeleton of human brain microvascular endothelial cells.

The fungal pathogen Cryptococcus neoformans has a predilection for the central nervous system (CNS), resulting in devastating meningoencephalitis. At present, it is unclear how C. neoformans traverses the blood-brain barrier (BBB) and causes CNS infection. The present study has examined and characterized the interaction of C. neoformans with human brain microvascular endothelial cells (HBMEC), which constitute the BBB. Adhesion of and transcytosis of HBMEC by C. neoformans was inoculum- and time-dependent and occurred with both encapsulated and acapsulated strains. C. neoformans induced marked morphological changes in HBMEC, for example membrane ruffling, irregular nuclear morphology and swelling of the mitochondria and the ER. These findings suggest that C. neoformans induced actin cytoskeletal reorganization of the host cells. In addition, it was observed that the dephosphorylated form of cofilin was increased during cryptococcal adherence to HBMEC, concomitant with the actin rearrangement. Cryptococcal binding to HBMEC was increased in the presence of Y27632, a Rho kinase (ROCK)-specific inhibitor. Since ROCK activates LIM kinase (LIMK), which phosphorylates cofilin (inactive form), this suggests the involvement of the ROCK-->LIMK-->cofilin pathway. In contrast, the phosphatase inhibitor sodium orthovanadate decreased adherence of Cryptococcus to HBMEC, concomitant with the increase of phosphorylation of cofilin. Furthermore, the tight junction marker protein occludin became Triton-extractable, indicating alteration of tight junctions in brain endothelial cells. This is the first demonstration that C. neoformans is able to adhere to and transcytose across the HBMEC monolayer and alter the cytoskeleton morphology in HBMEC. Further characterization of the interactions between C. neoformans and HBMEC should help the development of novel strategies to prevent cryptococcal meningitis and its associated morbidity.

Actin Depolymerizing Factors↗
PubMed2003

Ultrastructural changes in subepithelial capillaries and their surrounding stroma in rat prostate and seminal vesicle after castration.

The purpose of this study was to clarify the androgen-ablation-induced morphological changes in the capillaries and stroma near the epithelial cells in prostate and seminal vesicles (SV) using transmission electron microscopy (TEM). In ventral prostate (VP) and SV of immature male rats, the luminal areas of subepithelial capillaries and the width of the stromal layers between endothelia and epithelia were measured quantitatively after castration using TEM and a computed image analyzer. The luminal areas of the capillaries were significantly reduced in VP and SV in the short-term after castration. In the stromal layer, the width of the collagen layer surrounding the capillary significantly increased in VP and SV in the long-term after castration. These data suggest that the reduction of the capillaries and the thickening of collagen surrounding them are related to the involution of glandular epithelial cells in VP and SV after castration.

Animals↗
PubMed2003

[Treatment strategy for locally advanced prostate cancer].

With the increasing aged population, prostate cancer has become one of the commonest malignant tumors in the United States. The incidence of prostate cancer is the highest among malignant tumors in males, and the mortality rate is the second highest following lung cancer. Even when prostate cancer is diagnosed to be in the early stage preoperatively, its excised lesions are often judged pathohistologically to be locally advanced tumor (staging error). Therefore, to estimate the exact pathological stage of excised lesions by preoperative parameters such as clinical T, PSA and biopsy Gleason Score, Partin's nomogram is generally used in the United States. However, according to the annual update version of the 2001 millennium update, radical prostatectomy should not be applied to T3, and it was excluded from the nomogram. Currently, the standard methods for the treatment of locally advanced prostate cancer may be external beam radiotherapy and brachytherapy with neoadjuvant hormonal therapy and intraprostate 125I and 103Pd seeds with neoadjuvant hormonal therapy, although the long-term results are unknown. In our study, similar to a report by Messing et al., adjuvant hormonal therapy might be effective in patients in whom the tumor was diagnosed as being in the early stage but was later found to be N (+) after its operation.

Brachytherapy↗
PubMed2003

[Clinical study of endocrine therapy in stage B and C prostate cancer].

To evaluate the usefulness of endocrine therapy for stage B and C prostate cancer, we carried out a retrospective study on overall survival rate, cause-specific survival, PSA recurrence-free rate, and their predictive factors in 118 patients with stage B prostate cancer, 61 with stage C prostate cancer who underwent endocrine therapy at our department between 1985 and 2001. The cause-specific survival rate and PSA recurrence-free rate of stage B patients who underwent endocrine therapy were well, and they will take a good clinical course. Thus, in this stage of prostate cancer, aged patients and patients with complications may be good candidates for endocrine therapy. The cause-specific survival rate and PSA recurrence-free rate in the stage C patients who underwent endocrine therapy were significantly low. In stage C patients, endocrine therapy should be combined early with other methods such as radiotherapy. In the stage B patients who underwent endocrine therapy, PSA and Gleason score appeared to be associated with the cause-specific survival rate and PSA recurrence-free rate.

Aged↗
PubMed2002

The diagnostic accuracy of the age-adjusted and prostate volume-adjusted biopsy method in males with prostate specific antigen levels of 4.1-10.0 ng/mL.

BACKGROUND: The authors evaluated a new age-adjusted and prostate volume-adjusted biopsy method for the detection of prostate carcinoma through the transperineal and the transrectal approaches in men with PSA levels of 4.1-10.0 ng/mL. METHODS: The value of the adjusted biopsy method was calculated by using the following four factors: 1) life expectancy in Japanese men in 1998, 2) prostate volume estimated by transrectal ultrasonography, 3) tumor doubling time (4 years), and 4) tumor volume that influenced death (20 cc). The number of biopsy sites was set at 8-20. Between August, 1999 and December, 2001, 100 men age or= 50 cc, and men with PSA density (PSAD) levels /= 50 cc), and patients with PSAD levels <or= 0.15 ng/mL/cc. The authors recommend that patients undergo an additional transition zone biopsy at the anterior aspect through the transperineal approach.

Age Factors↗
PubMed2002

Biphasic modulation of synaptic transmission by hypertonicity at the embryonic Drosophila neuromuscular junction.

Puff-application of hypertonic saline (sucrose added to external saline) causes a transient increase in the frequency of spontaneous miniature synaptic currents (mSCs) at the neuromuscular junctions of Drosophila embryos. The frequency gradually returns to pre-application levels. External Ca(2+) is not needed for this response, but it may modify it. At 50 mM added sucrose, for example, enhanced spontaneous release was observed only in the presence of external Ca(2+), suggesting that Ca(2+) augments the response. In a high-K(+) solution, in which the basal mSC frequency was elevated, higher sucrose concentrations produced an increase in mSC frequency that was followed (during and after the hypertonic exposure) by depression, with the magnitude of both effects increasing with hypertonicity between 100 and 500 mM. Evoked release by nerve stimulation showed only depression in response to hypertonicity. We do not believe that the depression of spontaneous or evoked release can be explained by the depletion of releasable quanta, however, since the frequency of quantal release did not reach levels compatible with this explanation and the enhancement and depression could be obtained independent of one another. In a mutant lacking neuronal synaptobrevin, only the depression of mSC frequency was induced by hypertonicity. Conversely, only the enhancing effect was observed in wild-type embryos when the mSC frequency was elevated with forskolin in Ca(2+)-free saline. In cultured embryonic Drosophila neurons, Ca(2+) signals that were induced by high K(+) and detected by Fura-2, were reduced by hypertonicity, suggesting that the depressing response is due to a direct effect of hypertonicity on Ca(2+) influx.

Animals↗
PubMed2002

Class IV semaphorin Sema4A enhances T-cell activation and interacts with Tim-2.

Semaphorins are a family of phylogenetically conserved soluble and transmembrane proteins. Although many soluble semaphorins deliver guidance cues to migrating axons during neuronal development, some members are involved in immune responses. For example, CD100 (also known as Sema4D), a class IV transmembrane semaphorin, signals through CD72 to effect nonredundant roles in immune responses in a ligand-receptor system that is distinct from any seen previously in the nervous system. Here we report that the class IV semaphorin Sema4A, which is expressed in dendritic cells and B cells, enhances the in vitro activation and differentiation of T cells and the in vivo generation of antigen-specific T cells. Treating mice with monoclonal antibodies against Sema4A blocks the development of an experimental autoimmune encephalomyelitis that is induced by an antigenic peptide derived from myelin oligodendrocyte glycoprotein. In addition, expression cloning shows that the Sema4A receptor is Tim-2, a member of the family of T-cell immunoglobulin domain and mucin domain (Tim) proteins that is expressed on activated T cells.

Amino Acid Motifs↗
PubMed2002

Antisense oligonucleotide to cofilin enhances respiratory burst and phagocytosis in opsonized zymosan-stimulated mouse macrophage J774.1 cells.

Phagocytes play a central role in the host defense system, and the relationship between the mechanism of their activation and cytoskeletal reorganization has been studied. We have previously reported a possible involvement of cofilin, an actin-binding protein, in phagocyte functions through its phosphorylation/dephosphorylation and translocation to the plasma membrane regions. In this work, we have obtained a new line of evidence showing an important role of cofilin in phagocyte functions using the mouse macrophage cell line J774.1 and an antisense oligonucleotide to cofilin. Upon stimulation with opsonized zymosan (OZ), cofilin was phosphorylated, and it accumulated around phagocytic vesicles. As the antisense oligonucleotide to cofilin, a 20-mer S-oligo corresponding to the sequence including the AUG translational initiation site was found to be effective. In the cells treated with the antisense oligonucleotide, the amount of cofilin was less than 30% of that in the control cells, and the level of F-actin was two or three times higher than that in the control cells before and throughout the cell activation. In the antisense oligonucleotide-treated cells, OZ-triggered superoxide production was three times faster than that in the control cells. Furthermore, phagocytosis of OZ was enhanced by the antisense. These results show that cofilin plays an essential role in the control of phagocyte function through regulation of actin filament dynamics.

Actin Depolymerizing Factors↗