712 research outputs found
Ultrasonication-induced Amyloid Fibril Formation of β2-Microglobulin
No full textThis research was originally published in the Journal of Biological Chemistry. Yumiko Ohhashi, Miho Kihara, Hironobu Naiki and Yuji Goto. Ultrasonication-induced Amyloid Fibril Formation of β2-Microglobulin. J. Biol. Chem. 2005; 280, 32843-32848. © the American Society for Biochemistry and Molecular BiologyTo obtain insight into the mechanism of fibril formation, we examined the effects of ultrasonication, a strong agitator, on β2 -microglobulin (β2-m), a protein responsible for dialysis-related amyloidosis. Upon sonication of an acid-unfolded β2-m solution at pH 2.5, thioflavin T fluorescence increased markedly after a lag time of 1–2 h with a simultaneous increase of light scattering. Atomic force microscopy images showed the formation of a large number of short fibrils 3 nm in diameter. When the sonication-induced fibrils were used as seeds in the next seeding experiment at pH 2.5, a rapid and intense formation of long fibrils 3 nm in diameter was observed demonstrating seed-dependent fibril growth. We then examined the effects of sonication on the native β2-m at neutral pH, conditions under which amyloid deposits occur in patients. In the presence of 0.5 mm sodium dodecyl sulfate, a model compound of potential trigger and stabilizer of amyloid fibrils in patients, a marked increase of thioflavin T fluorescence was observed after 1 day of sonication at pH 7.0. The products of sonication caused the accelerated fibril formation at pH 7.0. Atomic force microscopy images showed that the fibrils formed at pH 7.0 have a diameter of more than 7 nm, thicker than those prepared at pH 2.5. These results indicate that ultrasonication is one form of agitation triggering the formation of amyloid fibrils of β2-m, producing fibrils adapted to the respective pH
Conformation of Amyloid Fibrils of β2-Microglobulin Probed by Tryptophan Mutagenesis
No full textThis research was originally published in the Journal of Biological Chemistry. Miho Kihara, Eri Chatani, Kentaro Iwata, Kaori Yamamoto, Takanori Matsuura, Atsushi Nakagawa, Hironobu Naiki and Yuji Goto. Conformation of Amyloid Fibrils of β2-Microglobulin Probed by Tryptophan Mutagenesis. J. Biol. Chem. 2006; 281, 31061–31069. © the American Society for Biochemistry and Molecular Biologyβ2-Microglobulin (β2-m), a protein responsible for dialysis-related amyloidosis, adopts an immunoglobulin domain fold in its native state. Although β2-m has Trp residues at positions 60 and 95, both are located near the surface of the domain. Hence, β2-m does not have a conserved Trp common to other immunoglobulin domains, which is buried in close proximity to the disulfide bond. To study the structure of amyloid fibrils in relation to their native fold, we prepared a series of Trp mutants. Trp60 and Trp95 were both replaced with Phe, and a single Trp was introduced at various positions. Among various mutants, W39-β2-m, in which a Trp was introduced at the position corresponding to the conserved Trp, exhibited a remarkable quenching of fluorescence in the native state, as observed for other immunoglobulin domains. An x-ray structural analysis revealed that W39-β2-m assumes the native fold with Trp39 located in the vicinity of the disulfide bond. Comparison of the fluorescence spectra of various mutants for the native and fibrillar forms indicated that, while the Trp residues introduced in the middle of the β2-m sequence tend to be buried in the fibrils, those located in the C-terminal region are more exposed. In addition, the fluorescence spectra of fibrils prepared at pH 2.5 and 7.0 revealed a large difference in the fluorescence intensity for W60-β2-m, implying a major structural difference between them
Seeding-dependent Maturation of β2-Microglobulin Amyloid Fibrils at Neutral pH
No full textThis research was originally published in the Journal of Biological Chemistry. Miho Kihara, Eri Chatani, Miyo Sakai, Kazuhiro Hasegawa, Hironobu Naiki and Yuji Goto. Seeding-dependent Maturation of β2-Microglobulin Amyloid Fibrils at Neutral pH. J. Biol. Chem. 2005; 280, 12012-12018. © the American Society for Biochemistry and Molecular Biologyβ2-Microglobulin (β2-m) is a major component of amyloid fibrils deposited in patients with dialysis-related amyloidosis. Recent studies have focused on the mechanism by which amyloid fibrils are formed under physiological conditions, which had been difficult to reproduce quantitatively. Yamamoto et al. (Yamamoto, S., Hasegawa, K., Yamaguchi, I., Tsutsumi, S., Kardos, J., Goto, Y., Gejyo, F. & Naiki, H. (2004) Biochemistry 43, 11075-11082) showed that a combination of seed fibrils prepared under acidic conditions and a low concentration of sodium dodecyl sulfate below its critical micelle concentration enabled extensive fibril formation at pH 7.0. Here, we found that repeated self-seeding at pH 7.0 with fibrils formed at the same pH causes a marked acceleration of growth, indicating the maturation of fibrils. The observed maturation can be simulated by assuming the existence of two types of fibrils with different growth rates. Importantly, some mutations of β2-m or the addition of a low concentration of urea, both destabilizing the native conformation, were not enough to extend the fibrils at pH 7.0, and a low concentration of sodium dodecyl sulfate (i.e. 0.5 mm) was essential. Thus, even though the first stage fibrils in patients are unstable and require stabilizing factors to remain at neutral pH, they can adapt to a neutral pH with repeated self-seeding, implying a mechanism of development of amyloid deposition after a long latent period in patients
Primary paraganglioma of the urinary bladder: a report of two cases
No full textWe report two cases of primary paraganglioma of the urinary bladder. Case 1. A 61-year-old man was hospitalized with the chief complaints of gross hematuria, dysuria and headache. The patient had a history of hypertension. Cystoscopy disclosed a nonpapillary, sessile tumor in the retrotrigonum of the bladder. An attack of paroxysmal hypertension was induced by bimanual palpation of the tumor, and paraganglioma was suspected. Partial cystectomy with staging pelvic lymphadenectomy was performed. Case 2. A 65-year-old man was hospitalized with the chief complaints of gross hematuria and urinary retention. The patient had no history of hypertension. Cystoscopy disclosed a nonpapillary tumor in the right lateral wall of the bladder. Transurethral resection was performed with no cardiovascular complication. Prostatic needle biopsy showed the histological evidence of prostatic adenocarcinoma. Radical retropubic prostatectomy with limited lymphadenectomy was performed. There was no histological evidence of lymph node involvement of paraganglioma or adenocarcinoma. The histological and biochemical examinations revealed a chromaffin positive, functioning and non-malignant tumor in Case 1, and a chromaffin negative, non-functioning and non-malignant tumor in Case 2. In total, 29 cases of primary paraganglioma of the urinary bladder have been so far reported in Japan. The tumor recurrence, multiple or metastases were recorded in 8 of 29 cases (27.6%), mainly in regional lymph node metastases. We recommend lymphadenectomy at the initial operation, irrespective of pathological finding of the primary paraganglioma of the urinary bladder
Intravesical bacillus Calmette-Guerin therapy for superficial bladder tumor: experience of 13 cases
No full textWe treated 13 patients with superficial bladder cancer via intravesical bacillus Calmette-Guerin (BCG) for 1) prophylaxis of recurrent tumor (prophylaxis group, 8 patients), and 2) therapy of carcinoma in situ (CIS group, 5 patients), with a mean follow up of 13.3 and 14.2 months, respectively. BCG (Tokyo 172 strain) was given intravesically (80 mg in 40 ml, saline) weekly for 8 weeks after transurethral resection or biopsies. In the prophylaxis group, the recurrence rate per 100 patient-months was significantly decreased from 16.1 to 2.83, before and after the BCG therapy (p less than 0.005, chi-square). In 6 patients on whom previous intravesical chemotherapy (MMC and/or ADM) was unsuccessful, the recurrence rate at 100 patient-months was significantly decreased from 15.3 to 2.33, before and after the BCG therapy (p less than 0.005, chi-square). Therefore, we considered that BCG therapy was effective for the patients on whom previous intravesical chemotherapy was unsuccessful. In the CIS group, urine cytology changed to negative in all patients after the BCG therapy. Four of the 5 patients had no recurrence for a mean follow up of 13.8 months. In our cases (12 cases), OKT-4, and OKT-8 proportion of peripheral blood lymphocytes measured from immune reactions had not significantly changed after BCG therapy. This study suggests that BCG is effective not only in therapy of CIS, but in prophylaxis of previously treated cases
Optical internal urethrotomy after traumatic disruption of the urethra
No full textWe report 4 cases of complete traumatic disruption of urethra treated by endoscopic management, core-through optical internal urethrotomy. A direct vision urethrotome was used to incise the totally obliterated urethra with transvesical endoscopic guidance and digital rectal or perineal control. Postoperatively, the patients required an average of 1.3 subsequent urethrotomies. The results were satisfactory in three cases and one case was under observation. All patients were continent and three of them were potent. We suggest that the endoscopic approach should be considered as an initial procedure for restoring urethral continuity prior to more extensive surgical repair
CT-guided biopsy of paraaortic lesions: report of three cases
No full textComputed tomographic (CT)-guided biopsies of the lesions in paraaortic region were performed for three urologic disease conditions: retroperitoneal fibrosis, lymph node metastases of transitional cell carcinoma of renal pelvis and lymph node metastasis of renal cell carcinoma. The biopsies were performed without complications using the Bard Biopty biopsy gun with a Bard Biopty-Cut needle. Every biopsy specimen we obtained by the Biopty rendered an excellent biopsy core from which a definite histopathological diagnosis was made. CT-guided biopsy is considered to be safe and useful for diagnosis of the disease of the paraaortic region, even when ultrasonography guided biopsy is difficult. The use of the Biopty for CT-guided biopsy provides a high quality specimen for histopathological diagnosis
Urinary continence in patients undergoing nerve sparing radical prostatectomy
No full text神経保存的前立腺全摘術20例と従来の術式による前立腺全摘術13例とで術後の排尿コントロールおよび尿道機能につき比較検討した.1)術後continentであった症例は, 神経保存群で14例, 従来群で6例であり, 尿失禁のある場合も, 神経保存群ではその程度が軽い.2)術後1ヵ月目の平均最高尿道内圧は, 神経保存群31.5±5.4 cmH2O, 従来群23.2±5.7 cmH2Oであり, 機能的尿道長では両群の間に有意差はみられなかった.3)前立腺全摘術において神経血管束を保存することは, 術後の勃起機能の保持の面からではなく, 排尿コントロールに対して重要な意味を持つRecently, the morbidity of radical prostatectomy has been reduced by improvements in surgical techniques and greater understanding of pelvic anatomy. The nerve sparing technique has been considered to be a major contribution to this advance. In our study, urinary control was compared in 33 consecutive patients undergoing a radical retropubic prostatectomy. In 13 patients, a conventional radical prostatectomy was performed and in 20 subsequent patients, a nerve sparing operation was performed. The staff surgeons were the same throughout the study. The age of the patients and pathological stage of the tumor were not significantly different between the groups. The operative time was shorter and intraoperative blood loss was less both significantly in the nerve sparing group. In the conventional operated group, there was one patient with total incontinence and two with significant incontinence requiring absorbable pads. In the nerve sparing group, there were no patients having total incontinence and one had stress incontinence requiring absorbable pads. Urethral pressure profile was measured postoperatively in 17 in the nerve sparing group and in 7 in the conventional group. The maximum urethral pressure in the nerve sparing group was 31.5 cm H2O (SD = 5.4) and in the conventional group 23.2 cm H2O (SD = 5.7) with a significant difference between groups (p less than 0.01). The functional urethral length of the nerve sparing group was 16.7 mm (SD = 5.2) and in the conventional group 13.3 mm (SD = 3.7) with no significant difference between the groups. These results suggest that preservation of neurovascular bundles from the pelvic plexus during radical prostatectomy has no important role in postoperative urinary continence
Author response image 1.
No full textNeurotransmitter is released at synapses by fusion of synaptic vesicles with the plasma membrane. To sustain synaptic transmission, compensatory retrieval of membranes and vesicular proteins is essential. We combined capacitance measurements and pH-imaging via pH-sensitive vesicular protein marker (anti-synaptotagmin2-cypHer5E), and compared the retrieval kinetics of membranes and vesicular proteins at the calyx of Held synapse. Membrane and Syt2 were retrieved with a similar time course when slow endocytosis was elicited. When fast endocytosis was elicited, Syt2 was still retrieved together with the membrane, but endocytosed organelle re-acidification was slowed down, which provides strong evidence for two distinct endocytotic pathways. Strikingly, CaM inhibitors or the inhibition of the Ca2+-calmodulin-Munc13-1 signaling pathway only impaired the uptake of Syt2 while leaving membrane retrieval intact, indicating different recycling mechanisms for membranes and vesicle proteins. Our data identify a novel mechanism of stimulus-and Ca2+-dependent regulation of coordinated endocytosis of synaptic membranes and vesicle proteins
Statistics of the operation at Division of Urology, Shimada Municipal Hospital: 1987-1991
No full text1)年間入院患者数は徐々に増加してきたが, 最近の2年間は約300人で固定した。2)手術件数はESWLを除くと減少傾向を示した。年間の平均件数は約200件となった。3)60歳以上の人が占める割合はほぼ40～50%であった。4)前立腺肥大症に対する手術は年間50～60件で, 全体の約18%になった。5)悪性腫瘍の手術は年間約30件で, 全体の10～15%であった。6)全身麻酔は全体の約18%, 脊椎麻酔は約42%を占めたA recent 5-year (1987-1991) statistic survey was carried out on the operations experienced at the Division of Urology, Shimada Municipal Hospital
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