Biomedical subjects

Yasuo Yoshioka

Publications and source records attributed to Yasuo Yoshioka.

At least 37 records · Page 2Linked to original sources

PubMed2004

Optimal site-specific PEGylation of mutant TNF-alpha improves its antitumor potency.

Recently, we created a lysine-deficient mutant tumor necrosis factor-alpha [mTNF-alpha-Lys(-)] with full bioactivity in vitro compared with wild-type TNF-alpha (wTNF-alpha), and site-specific PEGylation of mTNF-alpha-Lys(-) was found to selectively enhance its in vivo antitumor activity. In this study, we attempted to optimize this PEGylation of mTNF-alpha-Lys(-) to further improve its therapeutic potency. mTNF-alpha-Lys(-) was site-specifically modified at its N-terminus with linear polyethylene glycol (LPEG) or branched PEG (BPEG). While randomly mono-PEGylated wTNF-alpha (ran-LPEG5K-wTNF-alpha) with 5 kDa of LPEG (LPEG5K) had about only 4% in vitro bioactivity of wTNF-alpha, mono-PEGylated mTNF-alpha-Lys(-) [sp-PEG-mTNF-alpha-Lys(-)] with LPEG5K, LPEG20K, BPEG10K, and BPEG40K had 82%, 58%, 93%, and 65% bioactivities of mTNF-alpha-Lys(-), respectively. sp-LPEG-mTNF-alpha-Lys(-) and sp-BPEG10K-mTNF-alpha-Lys(-) had much superior antitumor activity to those of both unmodified TNF-alphas and ran-LPEG5K-wTNF-alpha, though sp-BPEG40K-mTNF-alpha-Lys(-) did not show in vivo antitumor activity. Thus, the molecular shape and weight of PEG may strongly influence the in vivo antitumor activity of sp-PEG-mTNF-alpha-Lys(-).

Animals↗

PubMed2004

Poly(vinylpyrrolidone-co-dimethyl maleic acid) as a novel renal targeting carrier.

Poly(vinylpyrrolidone-co-dimethyl maleic acid) (PVD) was found to have high renal-targeting capability and safety as a drug carrier. To optimize the renal drug delivery system using PVD, the relationship between the molecular weight of PVD and its renal accumulation were evaluated in mice by their intravenous injection. It was found that the molecular size of 6-8 kDa was associated with the highest renal accumulation. The specific bioactivity of PVD-conjugated superoxide dismutase (SOD) relative to that of unmodified SOD gradually decreased with an increase in the degree of modification to SOD with PVD6K. The conjugated SOD (L-PVD-SOD) with the molecular size of 73 kDa, which had comparable specific bioactivity with native SOD, showed longer plasma half-life than native SOD. About sixfold more L-PVD-SOD was distributed to the kidneys than native SOD 3 h after intravenous injection, whereas extensive PVD modification did not enhance the renal accumulation of SOD. This L-PVD-SOD effectively accelerated recovery from mercuric chloride-induced acute renal failure in vivo. These results suggest that L-PVD-SOD may be the optimal derivative as a potential therapeutic agent to various renal diseases.

Acute Kidney Injury↗

PubMed2004

Lymph node metastasis of early oral tongue cancer after interstitial radiotherapy.

PURPOSE: To examine the prognostic factors for lymph node metastasis after brachytherapy for early (T1-T2N0M0) oral tongue cancer. METHODS AND MATERIALS: We reviewed the records of 571 patients (500 low dose rate and 71 high dose rate) treated at Osaka University Hospital between 1967 and 1999. RESULTS: Patients with lymph node metastasis had tumor with an average diameter of 26 +/- 8 mm and a thickness of 9 +/- 5 mm; for patients without lymph node metastasis, the corresponding dimensions were 23 +/- 8 mm and 7.5 +/- 4 mm (p = 0.0004 and 0.001, respectively). After 5 years, the ulcerative (48%) and indurative/infiltrative (39%) types showed a higher ratio of nodal involvement than the exophytic (31%) and superficial (19%) types (p <0.0001). Multivariate analysis showed ulceration (p = 0.006) and a thickness of <or =6 mm (p = 0.04) to be statistically significant predisposing factors for lymph node metastasis. The lymph node control rate was 68% in 1967-1979, 71% in 1980-1990, and 66% in 1990-1999; the corresponding successful salvage rates for lymph node metastasis were 43%, 33%, and 58% (p = 0.04). CONCLUSION: The appearance of the tumor, especially the presence or absence of ulceration and the diameter and thickness, are useful prognostic indicators for lymph node metastasis. Although the rates of lymph node metastasis did not change, the salvage outcome for recurrence after interstitial radiotherapy has recently improved.

Adult↗

PubMed2004

The use of PVP as a polymeric carrier to improve the plasma half-life of drugs.

To achieve an optimum drug delivery such as targeting or controlled release utilizing bioconjugation with polymeric modifier, the conjugate between drugs and polymeric modifiers must be designed to show desirable pharmacokinetic characteristics in vivo. In this study, we assessed the biopharmaceutical properties of various nonionic water-soluble polymers as polymeric drug carriers. Polyvinylpyrrolidone (PVP) showed the longest mean resident time (MRT) after i.v. injection of all nonionic polymers with the same molecular size. In fact, tumor necrosis factor-alpha (TNF-alpha) bioconjugated with PVP (PVP-TNF-alpha) circulated longer than TNF-alpha bioconjugated with polyethylene glycol (PEG-TNF-alpha) with the same molecular size. Each nonionic polymeric modifier showed a different tissue distribution. Dextran was accumulated in the spleen and liver. Polydimethylacrylamide (PDAAm) tended to distribute in the kidney. However, PVP showed the minimum volume of tissue distribution. These results suggested that PVP is the most suitable polymeric modifier for prolonging the circulation lifetime of a drug and localizing the conjugated drug in blood.

Animals↗

PubMed2004

The targeting of anionized polyvinylpyrrolidone to the renal system.

We reported that the co-polymer composed of vinylpyrrolidone and maleic acid selectively distributed into the kidneys after i.v. injection. To further optimize the renal drug delivery system, we assessed the renal targeting capability of anionized polyvinylpyrrolidone (PVP) derivatives after intravenous administration in mice. The elimination of anionized PVP derivatives from the blood decreased with increasing anionic groups, and the clearance of carboxylated PVP and sulfonated PVP from the blood was almost similar. But carboxylated PVP efficiently accumulated in the kidney, whereas sulfonated PVP was rapidly excreted in the urine. The renal levels of carboxylated PVP were about five-fold higher than sulfonated PVP. Additionally, carboxylated PVP was effectively taken up by the renal proximal tubular epithelial cells in vivo after i.v. injection. These anionized PVP derivatives did not show any cytotoxicity against renal tubular cells and endothelial cells in vitro. Thus, these carboxylated and sulfonated PVPs may be useful polymeric carriers for drug delivery to the kidney and bladder, respectively.

Animals↗

PubMed2004

Selective enhancer of tumor vascular permeability for optimization of cancer chemotherapy.

Clinical approach using tumor necrosis factor-alpha (TNF-alpha) as selective destruction against tumor endothelial cells and selective enhancer of tumor vascular permeability for effective accumulation of antitumor chemotherapeutic agents has attracted attention. However, the clinical application of TNF-alpha as a systemic antitumor agent has been limited because of toxic side-effects. To systemically use TNF-alpha as an antitumor agent and the selective enhancer of tumor vascular permeability, we assessed the usefulness of PEGylated TNF-alpha (PEG-TNF-alpha). PEG-TNF-alpha at a dose of 1000 JRU showed marked hemorrhagic necrosis in S-180 tumors without side-effects due to selective destruction of tumor vasculature, whereas wild-type TNF-alpha at a dose of 10,000 JRU showed a little hemorrhagic necrosis with severe side-effects. PEG-TNF-alpha induced the enhancement of tumor vascular permeability. The permeability was increased at 1 h, after an i.v. injection of PEG-TNF-alpha and returned to the basal level at 2 h. In addition, high molecular weight of PEG (molecular weight; 500K) accumulated in tumor tissue as well as low molecular weight of PEG (molecular weight; 12K). On the other hand, PEG-TNF-alpha didn't affect the permeability of normal tissue and inflammation site. This data suggested that PEG-TNF-alpha was useful agent as selective enhancer of tumor vascular permeability with safe.

Animals↗

PubMed2004

[Creation of functional muteins using phage libraries for pharmacoproteomic-based drug discovery and development of DDS].

Tumor necrosis factor-alpha (TNF-alpha) has been expected to be a promising new antitumor agent, but toxic side effects by the systemic administration of TNF-alpha limit its clinical application. In this study, we attempted to improve the therapeutic potency of TNF-alpha by using our protein-drug innovation systems. Among phage libraries displaying various mutant TNF-alphas, we isolated some lysine-deficient super mutant TNF-alphas, typified by mTNF-alpha-K90R, with higher TNF-receptor affinities and stronger bioactivity in vitro, in spite of the importance of lysine residues for trimer formation and receptor binding. mTNF-alpha-K90R showed more than 10 times stronger in vivo antitumor effects and 1.3 times less toxicity than wild-type TNF-alpha (wTNF-alpha). Site-specifically mono-PEGylated mTNF-alpha-K90R (sp-PEG-mTNF-alpha-K90R) at N-terminus showed higher in vitro bioactivity than unmodified wTNF-alpha, whereas randomly mono-PEGylated wTNF-alpha at a lysine residue (ran-PEG-wTNF-alpha) had less than 6% of the bioactivity of wTNF-alpha. The antitumor therapeutic window of sp-PEG-mTNF-alpha-K90R was extended by about 5 times, 60 times and 18 times compared with those of mTNF-alpha-K90R, wTNF-alpha and ran-PEG-wTNF-alpha, respectively. sp-PEG-mTNF-alpha-K90R may, thus, be a potential systemic anti-tumor therapeutic agent. These data suggested that our fusion protein-drug innovation system composed of a creation system of functional mutant proteins based on phage display technique and a site-specific PEGylation system may open up a new avenue to the optimal protein therapy.

Animals↗

PubMed2004

Impact of mitochondrial DNA on radiation sensitivity of transformed human fibroblast cells: clonogenic survival, micronucleus formation and cellular ATP level.

The purpose of this study was to evaluate the impact of mitochondrial DNA (mtDNA) on the radiation sensitivity of transformed human fibroblast cells. The p+ and p0 human fibroblast cell lines were used, which carry wild-type mtDNA and no mtDNA, respectively. Clonogenic radiosensitivity was evaluated by colony formation assay and micronucleus (MN) formation assay. The ATP assay was then used to address the discrepancy between the results of the former two assays. Despite the lack of a significant difference in survival in the colony formation assay, p+ and p0 cells exhibited high and low radiosensitivities, respectively, in the MN formation assay (P < 0.003). This difference in MN formation correlated with high and low levels of cellular ATP content in p+ and p0 cells (P = 0.004). The addition of antimycin A suppressed differences in both MN formation and cellular ATP content. In the transformed human fibroblast cells we used, mtDNA played an important role in radiation-induced MN formation that was correlated with the levels of cellular ATP content. These results may imply the presence of an MN expression pathway that is dependent on the intrinsic ATP level and that may be compensated and lead to an equivalent level of clonogenic survival.

Adenosine Triphosphate↗

PubMed2004

Recent progress on tumor missile therapy and tumor vascular targeting therapy as a new approach.

Tumor targeting therapy, that is "Missile therapy", using a complex composed of a tumor suppressive drug and a whole antibody against tumor cells, is expected to become an attractive chemotherapy strategy. However, clinically convincing results have not yet been obtained mainly due to poor transport from the circulation to tumor tissue and marked toxicity. Recently, recombinant immunotoxins, composed of an Fv fragment of an antibody to a tumor-related antigen fused to various truncated toxins have been developed to overcome the distribution of immunotoxins in tumors. These recombinant immunotoxins have shown encouraging clinical results for some hematopoietic malignancies. However, there were no significant anti-tumor responses to many tumors, especially solid tumors, probably due to their rapid clearance from the circulation and their immunogenicity and antigenicity. More recently, PEGylation of recombinant immunotoxins has been attempted to overcome these drawbacks. It was found that PEGylation of recombinant immunotoxins improves their effectiveness. We discuss the recent progress in tumor missile therapy. In contrast to others, we developed "Missile therapy against tumor blood vessels" by using specific monoclonal antibodies against tumor endothelial cells rather than actual tumor cells. The complex between antibodies to tumor vascular endothelial cells and anti-tumor drugs can freely access the target cells without concern for their vascular permeability. These preparations have exhibited excellent anti-tumor effects for solid tumors. In this review, we also discuss this vascular targeting therapy as an attractive new strategy for tumor chemotherapy.

Animals↗

PubMed2003

Combination effects of complement regulatory proteins and anti-complement polymer.

We previously reported the development of a "cytomedicine" that consists of cells trapped in alginate-poly-L-lysine-alginate (APA) microcapsules and agarose microbeads. The functional cells that are entrapped in semipermeable polymer are completely isolated from cellular immune system. However, the ability of cytomedicine to isolate cells from the humoral immune system, which plays an essential role in xenograft rejection, is low. Therefore, the goal of the present study was to develop a novel cytomedicine that could protect the entrapped cells from injury of the complement system. We investigated the applicability of the complement regulatory protein (CRP), Crry, to cytomedicine. Crry-transfected cells entrapped within agarose microbeads resisted injury by complement to a degree, while entrapment of Crry transfected cells within agarose microbeads containing polyvinyl sulfate (PVS), a novel cytomedical device with anti-complement activity, clearly protected against complement attack. These data indicate that the combination of a CRP and a cytomedical device with anti-complement activity is a superior device for cytomedical therapy.

Animals↗

PubMed2003

Incorporation of adult organ-derived endothelial cells into tumor blood vessel.

In this study, we attempted to assess the incorporable potential of vascular endothelial cells derived from adult organ blood vessels into tumor blood vessels. Two kinds of adult organ-derived vascular endothelial cells, human aorta endothelial cells (HAEC) and umbilical vein endothelial cells (HUVEC), were administered into murine tumors inoculated to SCID mice. Many human blood vessel networks were visualized in the murine tumors. These cells in solid tumor not only survived and proliferated, but also incorporated into tumor endothelium. These results suggest that adult organ-derived vascular endothelial cells possess the potential to form the neovascular network in various tissues such as vascular endothelial progenitor-like cells in vivo. We propose that these cells can be regarded as a congenic (autologous) vector for vascular regeneration cell therapy and tumor vascular targeting gene therapy.

Adult↗

PubMed2003

A novel cytomedical vehicle capable of protecting cells against complement.

We have developed "Cytomedicine," which consists of functional cells entrapped in semipermeable polymer, and previously reported that APA microcapsules could protect the entrapped cells from injury by cellular immune system. However, microencapsulated cells were not protected from humoral immune system. Here, we developed a novel APA microcapsule, in which APA microbeads (APA(Ba) microbeads) were modified to contain a barium alginate hydrogel within their centers in an attempt to make it more difficult for antibody and complement to permeate the microcapsules. The permeability of APA(Ba) microbeads was clearly less than that of APA microcapsules, presumably due to the presence of barium alginate hydrogel. Cells encapsulated within APA(Ba) microbeads were protected against treatment with xenogeneic anti-serum. Furthermore, murine pancreatic beta-cells encapsulated in APA(Ba) microbeads remained viable and continued to secrete insulin in response to glucose. Therefore, APA(Ba) microbeads may be a useful carrier for developing anti-complement device for cytomedical therapy.

Alginates↗

PubMed2003

High-dose-rate brachytherapy as monotherapy for localized prostate cancer: a retrospective analysis with special focus on tolerance and chronic toxicity.

PURPOSE: To examine retrospectively fractionated high-dose-rate brachytherapy as monotherapy for localized prostate cancer with special focus on tolerance and toxicity, especially chronic toxicity. MATERIALS AND METHODS: Between May 1995 and October 2001, 43 patients with localized prostate cancer were treated with high-dose-rate brachytherapy without external beam irradiation at Osaka University Hospital. The stage was T1, T2, T3, and T4 in 8, 14, 18, and 3 patients, respectively. The adenocarcinoma was well, moderately, or poorly differentiated in 12, 16, and 15 patients, respectively. The median initial prostate-specific antigen level was 19.3 ng/mL (range 3.8-233.0). Thirty-eight patients also received hormonal therapy. Metallic needles were implanted transperineally under real-time ultrasound guidance, followed by a dose optimization program. Patients were irradiated twice daily at intervals of >6 h. A total dose of 54 Gy in nine fractions within 5 days (48 Gy in eight fractions within 5 days for the first 7 cases) was administered in one implant session. The median follow-up was 24 months (range 1-76). RESULTS: Radiation Therapy Oncology Group acute toxicity of Grade 4, 2, and 1 occurred in 1 (2%), 12 (28%), and 8 (19%) patients, respectively. Five patients had late toxicity: one with rectal ulcer (Grade 2) and four with rectal bleeding (Grade 1). The volume receiving 100% of the prescribed dose showed significant correlations with the incidence of acute and chronic toxicities (p = 0.005 and p = 0.014, respectively). The 3-year actuarial overall survival, local control, and biochemical no evidence of disease rate was 94%, 100%, and 55%, respectively. The crude biochemical control rate for low, intermediate, and high-risk patients was 100% (5 of 5), 80% (8 of 10), and 61% (17 of 28), respectively. CONCLUSIONS: High-dose-rate brachytherapy as monotherapy was found to be feasible and well tolerated. It showed a low chronic toxicity rate without any event of Radiation Therapy Oncology Group of Grade 3 or greater.

Adenocarcinoma↗

PubMed2003

Site-specific PEGylation of a lysine-deficient TNF-alpha with full bioactivity.

Addition of polyethylene glycol to protein (PEGylation) to improve stability and other characteristics is mostly nonspecific and may occur at all lysine residues, some of which may be within or near an active site. Resultant PEGylated proteins are heterogeneous and can show markedly lower bioactivity. We attempted to develop a strategy for site-specific mono-PEGylation using tumor necrosis factor-alpha (TNF-alpha). We prepared phage libraries expressing TNF-alpha mutants in which all the lysine residues were replaced with other amino acids. A fully bioactive lysine-deficient mutant TNF-alpha (mTNF-alpha-Lys(-)) was isolated by panning against TNF-alpha-neutralizing antibody despite reports that some lysine residues were essential for its bioactivity. mTNF-alpha-Lys(-) was site-specifically mono-PEGylated at its N terminus. This mono-PEGylated mTNF-alpha-Lys(-), with superior molecular uniformity, showed higher bioactivity in vitro and greater antitumor therapeutic potency than randomly mono-PEGylated wild-type TNF-alpha. These results suggest the usefulness of the phage display system for creating functional mutant proteins and of our site-specific PEGylation approach.

Animals↗

PubMed2003

Synthesis of a poly(vinylpyrrolidone-co-dimethyl maleic anhydride) co-polymer and its application for renal drug targeting.

We have synthesized a polymeric drug carrier, polyvinylpyrrolidone-co-dimethyl maleic anhydride [poly(VP-co-DMMAn)], for use in renal drug delivery. About 80% of the 10-kDa poly(VP-co-DMMAn) selectively accumulated in the kidneys 24 h after intravenous administration to mice. Although this accumulated poly(VP-co-DMMAn) was gradually excreted in the urine, about 40% remained in the kidneys 96 h after treatment. Poly(VP-co-DMMAn) was taken up by the renal proximal tubular epithelial cells and no cytotoxicity was noted. Higher doses did not produce toxicity in the kidneys or other tissues. In contrast, polyvinylpyrrolidone of the same molecular weight did not show any tissue-specific distribution. Poly(VP-co-DMMAn)-modified superoxide dismutase accumulated in the kidneys after intravenous administration and accelerated recovery from acute renal failure in a mouse model. In contrast, polyvinylpyrrolidone-modified superoxide dismutase and native superoxide dismutase were not as effective. Thus, poly(VP-co-DMMAn) is a useful candidate as a targeting carrier for renal drug delivery systems.

Acute Kidney Injury↗

PubMed2003

Results of low- and high-dose-rate interstitial brachytherapy for T3 mobile tongue cancer.

PURPOSE: To evaluate the treatment results of low-dose-rate (LDR) and high-dose-rate (HDR) interstitial brachytherapy (ISBT) for T3 mobile tongue cancer. MATERIAL AND METHODS: Between 1974 and 1992, 61 patients with T3 mobile tongue cancer were treated with LDR ISBT using (192)Ir hairpins with or without single pins. In addition, between 1991 and 1999, 14 patients were treated with HDR ISBT. For nine patients treated with ISBT alone, the total dose was 59-94 Gy (median 72 Gy) within one week in LDR ISBT and 60 Gy/10 fractions/5 days in HDR ISBT. For 66 patients treated with a combination therapy of external beam radiotherapy (EBRT) and ISBT, the total dose was 12.5-60 Gy (median 30 Gy) of EBRT and 50-112 Gy (median 68 Gy) within 1 week in LDR ISBT or 32-60 Gy (median 48 Gy)/8-10 fractions/5-7 days in HDR ISBT. RESULTS: The 2- and 3-year local control rates of all patients were both 68%. The 2- and 3-year local control rates of patients treated with LDR ISBT were both 67%, and those with HDR ISBT were both 71%. The local control rate of patients treated with HDR ISBT was similar to those with LDR ISBT. CONCLUSIONS: ISBT for T3 mobile tongue cancer is effective and acceptable. The treatment result of HDR ISBT is almost similar to that of LDR ISBT for T3 mobile tongue cancer.

Adult↗

PubMed2003

Anti-angiogenic effects of dimethyl sulfoxide on endothelial cells.

Dimethyl sulfoxide (DMSO) has anti-inflammatory and analgesic properties and is the only intravesical agent approved by the FDA for the treatment of interstitial cystitis. While it is known that DMSO has numerous biological effects on cell differentiation and alteration of cell-surface carbohydrate structures, the anti-inflammatory mechanism of DMSO has been not clear yet. Therefore, further investigation of DMSO in terms of inflammation therapy is needed. This study assessed the in vitro anti-angiogenic effects of DMSO on human aorta endothelial cells to clarify one of the mechanisms of its anti-inflammatory activity. DMSO did not affect expression of E-selectin on endothelial cells in the presence of TNF-alpha. Furthermore, DMSO effectively inhibited capillary tube formation; this mechanism would be due to suppression of matrix metalloproteinase-2 (MMP-2) production. These results provide useful knowledge about the anti-inflammatory effects of DMSO and the regulatory mechanism of MMP-2.

Angiogenesis Inhibitors↗

PubMed2003

Brachytherapy for early oral tongue cancer: low dose rate to high dose rate.

To examine the compatibility of low dose rate (LDR) with high dose rate (HDR) brachytherapy, we reviewed 399 patients with early oral tongue cancer (T1-2N0M0) treated solely by brachytherapy at Osaka University Hospital between 1967 and 1999. For patients in the LDR group (n = 341), the treatment sources consisted of Ir-192 pin for 227 patients (1973-1996; irradiated dose, 61-85 Gy; median, 70 Gy), Ra-226 needle for 113 patients (1967-1986; 55-93 Gy; median, 70 Gy). Ra-226 and Ir-192 were combined for one patient. Ir-192 HDR (microSelectron-HDR) was used for 58 patients in the HDR group (1991-present; 48-60 Gy; median, 60 Gy). LDR implantations were performed via oral and HDR via a submental/submandibular approach. The dose rates at the reference point for the LDR group were 0.30 to 0.8 Gy/h, and for the HDR group 1.0 to 3.4 Gy/min. The patients in the HDR group received a total dose of 48-60 Gy (8-10 fractions) during one week. Two fractions were administered per day (at least a 6-h interval). The 3- and 5-year local control rates for patients in the LDR group were 85% and 80%, respectively, and those in the HDR group were both 84%. HDR brachytherapy showed the same lymph-node control rate as did LDR brachytherapy (67% at 5 years). HDR brachytherapy achieved the same locoregional result as did LDR brachytherapy. A converting factor of 0.86 is applicable for HDR in the treatment of early oral tongue cancer.

Adult↗