Biomedical subjects

Ayako Suzuki

Publications and source records attributed to Ayako Suzuki.

26 records · Page 2Linked to original sources

PubMed2004

[Construction of a stress reaction scale based on an item response model and examination of the developmental process of psychological stress reactions by using test characteristic curves].

In this study, a stress reaction scale was constructed based on an Item Response Model, and the developmental process of psychological stress reactions was investigated by using test characteristic curves. Subjects consisted of 286 private college students and 234 national college students. The Job Stress Scale (JSS) was revised for college students, and used to assess psychological stress reaction. Graded response model of Item Response Theory (IRT) was used to estimate parameters. After estimating item and subject parameters, we assessed the precision of measurement and the fit of the model, and found both precision and fit to be satisfactory. Then we examined the test characteristic curves of each subscale to investigate the developmental process of psychological stress reactions of college students in comparison with company employees.

Adult↗

PubMed2003

In vivo anti-tumor effect through the controlled release of cisplatin from biodegradable gelatin hydrogel.

This paper is an investigation to achieve the in vivo controlled release of cisplatin (CDDP) from a biodegradable hydrogel. Hydrogels with different water contents were prepared through the chemical crosslinking of gelatin by various concentrations of glutaraldehyde. The gelatin hydrogel incorporating CDDP (CDDP-hydrogel) was prepared by allowing CDDP aqueous solution to sorb into the freeze-dried hydrogel. Irrespective of the hydrogel water content, approximately 10-30% of incorporated CDDP was released from the hydrogel in phosphate-buffered saline solution (PBS) at 37 degrees C within the initial 6 h, while little release was observed thereafter. The amount of CDDP released initially decreased with an increase in the time period of CDDP sorption. When intratumorally applied into Meth-AR-1 tumor-bearing mice, CDDP-hydrogel suppressed in vivo tumor growth to a significantly higher extent than free CDDP at the same dose. The survival rate was significantly higher by the application of CDDP-hydrogel of 40 microg CDDP. The CDDP concentration in the tumor tissue was maintained at a higher level for a longer time period than that of free CDDP. However, no problematic change in the mouse body and blood biochemical parameters was observed on the application of the CDDP-hydrogel. The time course of in vivo CDDP retention was in a good accordance with that of hydrogel remaining. Larger CDDP release was observed from the front surface of hydrogel onto which free CDDP was sorbed, than the back surface of hydrogel. These findings demonstrate that the controlled release of CDDP was based on biodegradation of the hydrogel carrier, but not simple diffusion of CDDP. It is possible that the CDDP molecules immobilized in the gelatin hydrogel were released from the hydrogel only when the hydrogel was degraded to generate some water-soluble gelatin fragments.

Animals↗

PubMed2003

Integration of orosensory and postingestive stimuli for the control of excessive fat intake in mice.

OBJECTIVES: Long-term preferences for, and reinforcement effects of, undigested fat substitutes were investigated by means of a two-bottle choice test and the conditioned place preference (CPP) test. METHODS: We tested intact corn oil and sorbitol fatty acid esters, which have been developed as non-digestible fat substitutes with low energy (1.5 kcal/g). RESULTS: Palatability of the sorbitol fatty acid esters was similar to corn oil over 30 min in the short-term two-bottle choice test in mice. However, mice did not continue to eat the fat substitute in the long-term two-bottle choice test, which included postprandial feedback effects. Moreover, sorbitol fatty acid ester did not act as a reinforcer in the CPP test. Mice with 0.1 mL of corn oil placed into their stomachs just before conditioning showed reinforcing effects on taking sorbitol fatty acid ester in the CPP test. However, intragastric administration of corn oil alone without stimulation of the oral cavity did not show any such reinforcing effects against corn oil. CONCLUSIONS: These results suggest that the postingestible effects of corn oil are involved in long-term preference and reinforcing effects.

Animals↗

PubMed2003

Increased hyaluronidase activity in the kidney of streptozotocin-induced diabetic rats.

We investigated changes in renal hyaluronidase activity in streptozotocin (STZ)-induced diabetic rats during the progression of diabetes. Prior to the study, we characterized rat renal hyaluronidase activity to find that its optimum pH is 3.5 and that it consists of two isomers of 73 and 63 kDa, as detected by zymography. Hyaluronidase activity was traced in one whole kidney and in the cortex and medulla of the other kidney up to the 18th week after STZ injection. Whole kidney hyaluronidase activity started to increase on day 3 and reached a maximum level 2.4 times that of the controls in the 3rd week. Cortical hyaluronidase showed a similar tendency to that of whole kidney hyaluronidase, while medullary hyaluronidase activity continued to increase until the 8th week, suggesting their different involvements in the progression of diabetic nephropathy. In zymography, the intensities of the two isomer bands increased with the progression of diabetes, but the intensity ratio did not change significantly and no new isomer band appeared. Renal HAase activity increased only in STZ-induced diabetic rats, but not in spontaneously diabetic Goto-Kakizaki rats still without remarkable renal disorder. Based on these findings, increased renal HAase activity may serve as a useful marker for diabetic nephropathy.

Animals↗

PubMed2003

PEP-19 overexpression in human uterine leiomyoma.

Although uterine leiomyomas represent one of the most common neoplasms in adult women, their pathogenesis remains poorly understood. A cDNA microarray analysis was performed to search for candidate genes expressed to a greater degree in leiomyoma compared with matched myometrium. A total of 15 candidate genes was obtained; neuron-specific protein PEP-19 (Purkinje cell protein 4; PCP 4) exhibited a striking difference in expression between leiomyoma and myometrium. Although PEP-19 expression has been reported exclusively in the central nervous system, the present study demonstrated that PEP-19 is also expressed in other human organs, including prostate, kidney and uterus. To clarify the role of PEP-19 in the pathogenesis of leiomyomas, PEP-19 expression was investigated for a series of human leiomyoma, as well as normal myometrium and leiomyosarcoma. PEP-19 mRNA and protein expression were much stronger in leiomyomas compared with normal myometrium, suggesting that PEP-19 might be involved in leiomyoma pathogenesis.

Adult↗

PubMed2002

Direct determination of pindolol enantiomers in human serum by column-switching LC-MS/MS using a phenylcarbamate-beta-cyclodextrin chiral column.

A direct analytical method of pindolol enantiomers in body fluids was developed by means of column-switching semi-microcolumn liquid chromatography/tandem mass spectrometry (LC-MS/MS). A pre-column packed with a silica-based cation-exchanger was used for on-line sample cleanup. Subsequent enantioseparation was conducted with a phenylcarbamate-beta-cyclodextrin (ph-beta-CD) bonded semi-micro chiral column (2.0 mm inner diameter (i.d.)). A 25-microl aliquot of serum/urine samples was directly injected into the system after simple filtration with a membrane filter. Separated enantiomers were monitored with positive electrospray ionization (ESI) and selected reaction monitoring (SRM). R(+)- and S(-)-pindolol in serum and urine were determined separately within 16 min at a resolution factor of 1.9. The detection limits at a signal-to-noise (S/N) ratio of 5 were 0.13 ng ml(-1) for both enantiomers. The linearity of the method was in the range of 0.25-100 ng ml(-1) with regression coefficient greater than 0.997. Recoveries from spiked serum and urine samples, estimated by the external standard method, were between 94.8 and 117.6% with a relative standard deviation (RSD) ranging from 2.1 to 18%.

Adrenergic beta-Antagonists↗

PubMed2002

Oral tolerance and pyruvate dehydrogenase in patients with primary biliary cirrhosis.

Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease characterized by the immunological destruction of intralobular bile ducts and serum anti-mitochondrial antibodies (AMA). Based upon previous work of oral tolerance and autoimmunity, we hypothesized that feeding the mitochondrial autoantigens of PBC would alter the clinical course and the level of antimitochondrial antibodies. The bovine pyruvate dehydrogenase complex (PDC) was purified and 5 mg fed in gelatin capsules to 6 patients with early stage PBC for 6 months. Antimitochondrial antibodies and liver biochemistries were measured at every 3 months for 12 months. The clinical trial was completed for all patients except for 1 who showed deterioration of pre-existing skin rash during treatment, which disappeared within 2 weeks after treatment was discontinued. However, after 1 year, neither the titers of AMAs nor liver biochemistries were significantly changed by this treatment. This is the first trial to test the efficacy of oral tolerance induction in PBC. However, the data, which limited in scope, did not demonstrate efficacy and further highlights the difficulties in showing continuing evidence of tolerance induction in autoimmunity.

Administration, Oral↗

PubMed2002

[Inter-observer agreement and validity of photographic dietary assessment].

PURPOSE: Estimation of nutritional intake from photographs of served meals has been proposed. We examined the inter-observer agreement and validity of this method for assessment of the daily diet. METHODS: Twenty-five family members (13 men and 12 women, mean age +/- SD: 47.3 +/- 5.6 years) of students in a dietetic course performed both meal photography and traditional weighed dietary records for four days. For the photo method, two observers independently identified foods and estimated their portion sizes from the photographs, converting them into energy and nutrient intake with a food composition table. The inter-observer agreement with the photo method was assessed in terms of inter-observer ratios, correlations, and coefficients of variation (CV), and the method was validated using the weighed dietary records as the reference. Its running cost was also calculated. RESULTS: The inter-observer ratios for estimation of mean daily nutritional intake ranged from 0.89 (magnesium) to 1.14 (retinol) with a median of 1.03. The correlation coefficients between observers varied from 0.65 (saturated fatty acids [SFA]) to 0.92 (vitamin C) on a daily basis (median, 0.79), and from 0.65 (SFA) to 0.96 (vitamin C) on an individual basis (median, 0.78). The CVs ranged from 7.9% (energy) to 23.8% (carotenc) (median, 13.3%), and from 5.2% (energy and magnesium) to 17.8% (carotene) (median, 8.8%) for daily and individual intake, respectively. Regarding validity, the ratios between methods (the photo method/weighed dietary records) ranged from 0.96 (potassium and SFA) to 1.11 (retinal and salt) with a median of 1.00. Correlations between the two methods were distributed from 0.40 (salt) to 0.82 (vitamin C and retinol) on a daily basis (median, 0.67), and from 0.47 (salt) to 0.90 (vitamin C) on an individual basis (median, 0.74). The CVs ranged from 10.5% (energy) to 39.6% (carotene) (median, 16.9%), and from 6.1% (protein) to 20.6% (carotene) (median, 11.2%), respectively. It was calculated to cost 105 Japanese yen per meal when using a lens-attached film for 25 shots. CONCLUSIONS: Inter-observer agreement and validity of the photo method, though varying with the nutrient, were generally acceptable. Although some modifications are needed for diners-out, the method appears to be useful as a dietary recording tool.

Diet Surveys↗