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Y Kojima

Publications and source records attributed to Y Kojima.

At least 55 records · Page 3Linked to original sources
PubMed2001

Effect of ultrasonic frequency on polymerization of styrene under sonication.

The effect of ultrasonic frequency on polymerization of styrene under sonication at 50 degrees C was studied at the frequencies of 23.4, 45.7, 92, 518 kHz and 1 MHz. Polymerization under sonication was carried out at the ultrasonic intensity that gives the same reaction rate of decomposition of porphyrin. The magnitude of the polymerization rate increases in the order of 92, 45.7 and 23.4 kHz. At the high frequencies of 518 kHz and 1 MHz, no polymerization was observed. These facts mean that there is an optimum frequency in the range from 92 to 518 kHz for effective polymerization. The average-number molecular weights at the sonication time of 3 h are 5.5 x 10(4), 8.0 x 10(4) and 11.5 x 10(4) for the irradiated frequencies of 92, 45.7 and 23.4 kHz, respectively. Sonication for 3 h at 92 kHz gives polystyrene with very high polydispersity, about 5.0, in comparison with the results obtained at 23.4 and 45.7 kHz. These observations indicate that polymerization under sonication is influenced by the irradiated frequency.

Journal Article↗
PubMed2001

Effect of sonication on nitroxide-controlled free radical polymerization of styrene.

Effect of sonication on the autopolymerization of styrene in the presence of 2,2,6,6-tetramethylpiperidinyl-1-oxy as the mediating radical was investigated at 110-135 degrees C. The thermal polymerization under sonication proceeded in the manner of a "living" radical polymerization to afford well-defined polystyrene. The sonication was found to decrease the induction period and increase the polymerization rate.

Journal Article↗
PubMed2001

Somatosensory evoked high frequency oscillations recorded from subdural electrodes.

OBJECTIVES: To examine high frequency oscillations (HFOs) of somatosensory evoked potentials (SEPs) recorded directly from subdural electrodes to investigate the relationship between the primary somatosensory cortex and HFOs. METHODS: SEPs were recorded directly from subdural electrodes previously implanted in 3 patients for clinical evaluation prior to surgical treatment of intractable epilepsy. RESULTS: The primary sensory cortex (area 3b) was proposed as the source of somatosensory HFOs, because the distribution of HFOs recorded from the subdural electrodes agreed with the distribution of the N20-P20 components of the somatosensory evoked potential. The somatosensory HFOs showed a strictly somatotopic source arrangement. There was a polarity inversion of the prophase component and also the N20-P20 component of HFOs across the central sulcus. However, the phase was synchronized in the latter part of the HFOs. CONCLUSIONS: We propose that the origins of the early and latter parts of HFOs are different, and that there was a clear somatotopy.

Adult↗
PubMed2001

Inflammatory bowel disease is associated with a novel promoter polymorphism of natural resistance-associated macrophage protein 1 (NRAMP1) gene.

Inflammatory bowel diseases (IBD) representing both Crohn's disease and ulcerative colitis are characterized by chronic activation of macrophages. Natural resistance-associated macrophage protein 1 (NRAMP1) gene regulates macrophage activation of antimicrobial activity and has many pleiotropic effects on macrophage functions. To explore the role of the NRAMP1 gene in IBD susceptibility, we examined the promoter sequence of the NRAMP1 gene whose polymorphisms have been reported to influence the transcriptional activity of the NRAMP1 gene. One novel allele (allele 7) and two previously reported alleles (alleles 2 and 3) have been determined in a Japanese population. We investigated the association of IBD with these three alleles. The allele frequency of allele 7 was significantly higher in patients with Crohn's disease (11.1%) and ulcerative colitis (11.2%) than those in the healthy control group (4.5%) (Pc=0.015, Pc=0.018, respectively). Therefore, our findings suggest that the novel promoter polymorphism of the NRAMP1 gene may influence susceptibility to IBD in the Japanese population.

Adult↗
PubMed2001

Multiple hepatic peribiliary cysts discovered incidentally at a medical examination.

We report a living patient with multiple hepatic peribiliary cysts. It was discovered incidentally during an ultrasonographic screening at a medical examination. Peribiliary cysts are multiple retention cysts of peribiliary glands. Although many autopsy cases of peribiliary cysts have been reported, there are few clinical cases of it in living patients. A CT performed immediately after drip-infusion cholangiography (DIC) was most useful for diagnosis in various imaging tests we performed.

Bile Ducts, Intrahepatic↗
PubMed2001

Primary and salvage urethroplasty using Mathieu meatal-based flip-flap technique for distal hypospadias.

BACKGROUND: Numerous surgical procedures have been attempted for correction of distal hypospadias. The Mathieu procedure was employed in this study for secondary cases as well as primary cases. METHODS: The length of the skin flap is determined by measuring the distance from the meatus to the glans tip and then the ventral meatal-based skin flap is incised. The proximal skin flap is flipped and anastomosed to the distal urethral plate. Additionally, subcutaneous tissue of the flipped flap is sutured to cover the original suture lines completely. RESULTS: The Mathieu urethroplasty was successful in one stage in 13 of the 16 primary repair cases (81%). Twelve of the 13 (92%) who underwent a secondary Mathieu procedure were successfully repaired with no problems. An overall success rate of 86% was achieved at the first operation for both primary and secondary cases. In the remaining 14% of the cases, success was achieved with only one additional procedure. CONCLUSIONS: The Mathieu flip-flap procedure is feasible for relatively short urethral defects if the ventral penile skin demonstrates adequate mobility and there is no chordee. Even in patients who require revisional hypospadias surgery, the Mathieu procedure can give excellent functional and cosmetic results.

Adolescent↗
PubMed2001

One-stage repair of moderately severe hypospadias using a transverse preputial tubularized island flap.

BACKGROUND: Transverse preputial tubularized island flap (TPTIF) urethroplasty has been used for the repair of moderately severe hypospadias since Duckett described the procedure in 1980. In spite of the excellent results reported by Duckett, subsequent studies showed high complication rates. A TPTIF procedure modified to reduce the complication rate is presented. METHODS: Between 1996 and 1997, 13 boys with moderately severe hypospadias were repaired with the TPTIF procedure. Patient age ranged from 10 months to 3 years with an average age of 23 months. To prevent urethrocutaneous fistula, the neourethra was constructed with a two-layer closure and the portion of anastomosis was wrapped between the native urethra and the neourethra with the tissue of the corpus spongiosum. RESULTS: The moderately severe hypospadias was repaired without complication in 12 of 13 patients. A urethrocutaneous fistula developed at the midshaft of the penis in one patient. No meatal stenosis, urethral stricture or diverticulum developed. CONCLUSION: Transverse preputial tubularized island flap urethroplasty provided excellent cosmetic and functional results for moderately severe hypospadias, and postoperative complications could be decreased by the two-layer closure of the neourethra and application of the wrapping technique of the proximal anastomosed portion with corpus spongiosum tissue.

Child, Preschool↗
PubMed2001

Tubularized incised-plate urethroplasty for secondary hypospadias surgery.

PURPOSE: Reoperation for failed hypospadias has been considered to be seriously bothersome because abundant penile skin does not tend to remain for urethroplasty or for penile shaft skin coverage. In this study, the tubularization of incised urethral plate was employed for those who had no excessive penile skin after failure of hypospadias repair. METHODS: Five patients with hypospadias underwent tubularized incised-plate urethroplasty as salvage surgery. The surgical techniques necessary for the performance of the reoperation were not different from those for the primary repair. The urethral plate was incised sufficiently deeply in its midline from the tip of the glans to the regressed meatus. The incised urethral plate was tubularized without tension over a catheter of an appropriate size. RESULTS: Four of those who underwent secondary tubularized incised-plate urethroplasty were successfully repaired without complications. A urethrocutaneous fistula occurred at the corona in the remaining patient. CONCLUSIONS: The absence of preputial skin in reoperative cases makes tubularized incised-plate urethroplasty the ideal option, although the series was small and postoperative duration is still short. In addition, this procedure can give excellent functional and cosmetic results even in patients who require revisional hypospadias surgery.

Adolescent↗
PubMed2001

The modified Koyanagi repair for severe proximal hypospadias.

OBJECTIVE: To report the method and results of a modified one-stage Koyanagi repair (urethroplasty with a parameatal-based and fully extended circumferential foreskin flap) to preserve the vascularity to the peripheral portion of the neourethra, in the repair of severe hypospadias. PATIENTS AND METHODS: Using a skin-incision line as in the original Koyanagi repair, a circumferential incision is made approximately 5 mm proximal to the corona and the urethral plate incised as for repair of chordee. A U-shaped skin incision is then made surrounding the meatus, extended to the dorsal prepuce for approximately 8 mm and parallel to the first incision. The tissue between the prepuce and dartos is dissected on the dorsal side to fix the prepuce as a neourethra to the dartos and to maintain blood supply. After mobilizing the loop-shaped skin flap through the button-hole of the pedicle, the internal and external sides of the loop are sutured to construct a neourethra. Twenty patients (aged 10 months to 9 years) with severe proximal hypospadias underwent the one-stage modified Koyanagi repair. RESULTS: The repair was successful after the initial procedure in 14 patients, but urethrocutaneous fistulae developed in three and meatal stenosis in three. The overall success rate was thus 70%. CONCLUSIONS: There were fewer complications than reported with the original Koyanagi repair, suggesting that the attempted vascular preservation of the neourethra was effective.

Child↗
PubMed2001

Role of advanced glycation end products in adynamic bone disease in patients with diabetic nephropathy.

Adynamic bone disease and elevated serum levels of advanced glycation end products (AGEs) often are found in patients with renal failure caused by diabetic nephropathy. To clarify the role of AGEs in adynamic bone disease, we investigated the effect of these substances on cultured human osteoblasts and parathyroid cells. After 72 hours of incubation with AGEs-bovine serum albumin (BSA) (1,000 microgram/mL), there was significant inhibition of the synthesis of type I collagen and osteocalcin in response to stimulation with 10(-10) to 10(-8) M of 1,25-dihydroxycholecalciferol. In a human osteoblastic cell line (MG 63), AGEs-BSA did not affect human osteocalcin promoter activity. In human parathyroid cells, a receptor for AGEs was detected by reverse-transcriptase polymerase chain reaction. Incubation with AGEs-BSA for 48 hours significantly inhibited parathyroid hormone secretion in response to a low calcium concentration of 0.81 mM (P < 0.01). In HEK-293 cells, expressing calcium-sensing receptors, the same AGE concentration caused a significant potentiation of the extracellular Ca(2+) induced-intracellular calcium concentration after 24 and 48 hours of incubation (P < 0.05 and P < 0.01). These data suggest that AGEs are involved in the pathogenesis of adynamic bone disease by inhibiting osteoblastic activity and by inhibiting parathyroid hormone secretion in response to hypocalcemia.

Calcitriol↗
PubMed2001

Rapid and wide-reaching delivery of HIV-1 env DNA vaccine by intranasal administration.

Although the potential of DNA vaccination is now beginning to be greatly appreciated, no detailed study of its localization in tissue or its expression kinetics has been reported. In this study, we investigated these issues using HIV-1 DNA plasmids administered either intranasally or intramuscularly. Fluorescence in situ hybridization (FISH) revealed that the human immunodeficiency virus (HIV) plasmids administered intranasally localized in the alveoli, lung, liver, spleen, regional lymph nodes, kidney, fetus, and esophagus. These HIV plasmids were detected 2 to 4 weeks after administration. We detected messenger RNA production of HIV env gene in the lung, liver and spleen, and human immunodeficiency virus type 1 (HIV-1)-specific proteins were detectable in the lung. These observations may provide important information for understanding the mechanisms of strong immune activation induced by DNA vaccination via the intranasal route. This technology of DNA administration suggests possible practical applications for vaccination and probably for gene therapy.

AIDS Vaccines↗
PubMed2001

Ab initio structure determination of monoclinic 2,2-dihydroxymethylbutanoic acid from synchrotron radiation powder diffraction data: combined use of direct methods and the Monte Carlo method.

The crystal structure of 2,2-dihydroxymethylbutanoic acid (C(6)H(12)O(4)) in monoclinic form has been determined ab initio from synchrotron radiation powder diffraction data. Two O and five C atoms were first derived by direct methods. Two missing O atoms and one C atom were found by the Monte Carlo method without applying constraint to their relative positions. Positional and isotropic displacement parameters of these non-H atoms were refined by the Rietveld method. Molecules are linked by hydrogen bonds and they make sheet-like networks running parallel to the (010) plane. The Monte Carlo method is demonstrated to be a powerful tool for finding missing atoms in partially solved structure.

Journal Article↗
PubMed2001

Appendectomy protects against the development of ulcerative colitis and reduces its recurrence: results of a multicenter case-controlled study in Japan.

OBJECTIVES: Studies in the US and Europe have shown that appendectomy may prevent the development of ulcerative colitis, but no detailed study has been conducted in Japan, where ulcerative colitis is uncommon and the population is racially homogeneous. In addition, there has been no detailed analysis of the relationship between appendectomy and the clinical course of ulcerative colitis. In this multicenter clinical study, we evaluated the effects of appendectomy on ulcerative colitis in Japan. METHODS: A case-control study was undertaken in seven medical institutions comparing the incidence of appendectomy and tonsillectomy in 325 patients with ulcerative colitis and 325 controls matched for age (10-yr intervals) and sex. Disease duration, extent, and prognosis were determined in 21 patients with ulcerative colitis who underwent appendectomies and 304 patients with ulcerative colitis who did not undergo appendectomies. RESULTS: Appendectomy was performed in a significantly lower percentage of patients in the ulcerative colitis group (21/325, 6.5%) than in the control group (53/325, 16.3%) (p < 0.001) (odds ratios = 0.355, 95% CI = 0.208-0.603). In contrast, no significant difference was observed between the groups with respect to tonsillectomy. The mean age (25.7 +/- 10.9 yr) of patients with ulcerative colitis at the time of appendectomy was significantly higher than the mean age (20.1 +/- 8.7 yr) of patients in the control group at the time of appendectomy (p < 0.05). The incidence of proctitis was higher in the appendectomy group than in the group that did not undergo appendectomies (38.1% vs 18.1%). In addition, the recurrence rates were significantly lower in the appenectomy group than in the group that did not undergo appendectomies (57. 1% vs 78.6%, p < 0.05), although both groups were similar in composition as to sex, age, duration of disease, smoking status, and previous medical treatment. CONCLUSIONS: Our results indicate that appendectomy has a negative association with and perhaps a preventive effect on the development of ulcerative colitis in the Japanese population. Furthermore, appendectomy also appears to reduce the extent and recurrence of ulcerative colitis.

Adult↗
PubMed2001

Hearing improvement after therapy for hyperlipidemia in patients with chronic-phase sudden deafness.

Hearing in patients with chronic-phase sudden deafness and associated hyperlipidemia tends to improve with therapy for hyperlipidemia. We studied 12 patients with unilateral sudden deafness and hyperlipidemia in whom more than 1 month had elapsed since the onset of the hearing disturbance. The disturbance was considered to be irreversible without therapy. The 4 men and 8 women ranged in age from 32 to 73 years, with a mean age of 54.3 years. The hearing disturbance was evaluated by measuring the air conduction thresholds at 125 to 8,000 Hz with pure tone audiometry. Hyperlipidemia was diagnosed when the total blood cholesterol level was 230 mg/dL or greater. The therapy for hyperlipidemia consisted of diet therapy and the administration of antilipemic agents. The hearing level was measured both before therapy and when the total blood cholesterol level had decreased to less than 230 mg/dL. After therapy, the mean hearing level had improved significantly (Wilcoxon's test, p < .05) at each of 125, 250, 500, and 2,000 Hz, but the changes in the level were not significant at 1,000, 4,000, or 8,000 Hz. Our results suggest that with therapy for hyperlipidemia, hearing tends to improve in patients with chronic-phase sudden deafness and associated hyperlipidemia, even when more than 1 month has elapsed since the onset of the presumably otherwise-irreversible hearing disturbance.

Adult↗
PubMed2001

New insulinomimetic zinc(II) complexes of alpha-amino acids and their derivatives with Zn(N2O2) coordination mode.

Zinc(II) complexes of alpha-amino acids and their derivatives with a Zn(N2O2) coordination mode were found to have in vitro insulinomimetic activity as estimated with the inhibition of free fatty acid release in isolated rat adipocytes treated with epinephrine. It was revealed that the insulinomimetic activities of zinc(II) complexes with over-all stability constants (log beta) less than 10.5 are higher than those of ZnSO4 and VOSO4. The high blood glucose level of KK-Ay mice with type 2 diabetes mellitus was lowered by daily intraperitoneal injections of a zinc(II) complex, cis-[Zn(L-Thr)2(H2O)2], for 14 d. The improvement of diabetes mellitus was confirmed with the oral glucose tolerance test.

Adipocytes↗
PubMed2001

Neonatal nucleated red blood cell counts in twins.

We counted nucleated red blood cells (NRBC) per 100 white blood cells (WBC) in the umbilical cord blood from 98 twins born to 49 women with uncomplicated twin pregnancies at > or = 34 weeks of gestation to better characterize NRBC in twins. Twelve women with monochorionic (MC) placentas and 37 with dichorionic (DC) placentas gave birth at 36.7 +/- .9 and 36.5 +/- 2 weeks of gestation, respectively. All twins were born with an Apgar score of > or = 7 at 1 min. Log10 (NRBC/100 BC) in 98 twins exhibited a nearly normal distribution, and was significantly associated with gestational age for both MC (r = -0.457, p = 0.025) and DC twins (r = - 0.275, p = 0.018), and with birth weight for both MC (r = -0.682, p < 0.001) and DC twins (r = -0.336, p = 0.003). Log10 (NRBC/100 WBC) tended to be larger in smaller twins than in larger twins in the MC group, and significantly larger in smaller twins than in larger twins in the DC group (p < 0.05). Intertwin difference in Log10 (NRBC/100 WBC) was defined as the value of Log10 (NRBC/100 WBC) of the smaller twin minus Log10 (NRBC/100 WBC) of the larger twin, and became greater with increasing intertwin difference in birth weight (r = 0.411, p = 0.003). These findings suggest that neonatal NRBC reflected gestational age and birth weight in twins. This preliminary observation using a small number of twins suggests that the smaller twin may have experienced a relative lack of oxygen compared with the larger twin in utero.

Adult↗
PubMed2001

[Young children's inference of moral disgust from situational and emotional response cues].

The main purposes of this study were to examine young children's ability to infer disgust in another person elicited by someone else's immoral action, and their ability to properly use the person's reactions in order to infer his/her emotion. Stories with pictures were used, and these abilities were compared with those for anger, which was also elicited by someone else's immoral action. Children of five and six years old, 52 and 54 respectively, and 251 undergraduates participated in the study. Main results were as follows: (a) children were adequately able to infer disgust in another person from a story showing a situation with an immoral action, although not as well as undergraduates; (b) children used the person's reaction toward the immoral action for inferring disgust as well as undergraduates did; and (c) inferring disgust for them seemed to be as easy as inferring anger.

Adult↗