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Biomedical subjects

T Nakao

Publications and source records attributed to T Nakao.

At least 19 recordsLinked to original sources
PubMed2006

Compensatory cortical activation during performance of an attention task by patients with diffuse axonal injury: a functional magnetic resonance imaging study.

OBJECTIVE: To determine how cortical compensation occurs in higher cognitive systems during the recovery phase of diffuse axonal injury (DAI). DESIGN: 12 right-handed patients with a magnetic resonance imaging (MRI) lesion pattern compatible with pure DAI were identified. Pure DAI was defined as finding of traumatic microbleeds on T2*-weighted gradient-echo images in the absence of otherwise traumatic or non-traumatic MRI abnormalities. 12 matched healthy controls were also enrolled. Functional magnetic resonance imaging (fMRI) was used to assess brain activation during a working memory test (Paced Visual Serial Attention Test (PVSAT)). RESULTS: No significant group differences were observed in reaction times for the PVSAT. Although patients with pure DAI committed a few errors during the PVSAT, controls respond correctly to each probe. Controls showed activations in the left frontal gyrus, left parietal gyrus and right inferior parietal gyrus. Patients with pure DAI showed activations in the left inferior frontal gyrus, right inferior frontal gyrus and right middle frontal gyrus. Between-group analysis of the PVSAT task showed significantly greater activation of the right inferior frontal gyrus (BA 45) and right middle frontal gyrus (BA 9) in patient with pure DAI versus controls. CONCLUSIONS: Patients with pure DAI require compensatory activation of the contralateral (right) prefrontal region to carry out activities similar to healthy controls. These findings provide further evidence for the adaptive capacity of neuronal systems and brain plasticity during the recovery stages of DAI.

Adolescent↗
PubMed2006

Milk progesterone profile at and after artificial insemination in repeat-breeding cows: effects on conception rate and embryonic death.

The aim of this study was to investigate whether the skim milk progesterone concentrations at artificial insemination (AI) and day of rise of post-ovulatory progesterone concentration thereafter affect the conception and embryonic death rates in repeat-breeding cows. Milk samples were obtained from 96 repeat-breeding cows that failed to conceive to three or more AIs. The samples were taken from the cows at the day of AI and three times/week until day 45 post-AI. Skim milk was obtained after centrifugation and used for progesterone assay. The cows with a progesterone concentration more than 0.5 ng/ml at AI showed a significantly higher incidence of late embryonic death than those having a progesterone concentration<0.5 ng/ml at AI (p<0.01). As the progesterone level at insemination rose, conception rate declined. A negative correlation was shown between conception rate and skim milk progesterone level at AI. Of 56 cows showing a rise of progesterone to 1 ng/ml or more within 6 days after AI, 28 cows (50%) conceived. On the contrary, only eight of 39 cows (20.5%) conceived when the progesterone rose up to 1 ng/ml after day 6 post-AI. We concluded that increased progesterone concentration at the time of AI and delayed rise of progesterone post-AI might lead to decrease in fertility in repeat-breeding cows.

Animals↗
PubMed2005

Plasma estrone sulphate (E1S) and estradiol-17beta (E2beta) profiles during pregnancy and their relationship with the relaxation of sacrosciatic ligament, and prediction of calving time in Holstein-Friesian cattle.

The objectives of this study were to investigate the plasma E(1)S and E(2)beta profiles during pregnancy and their relationship with the relaxation of sacrosciatic ligament in Holstein-Friesian cattle (n=37) and then to predict the calving time on the basis of E(1)S and E(2)beta profiles and relaxation of the ligament. Blood samples were collected at 4 weeks intervals from days 100 to 190, at 2 weeks intervals from days 190 to 250, every week from days 250 to 270 and thereafter every day from day 270 of gestation until the day after calving. The relaxation in the ligament was measured by using two scales as a distance at a schedule similar to blood sampling plus 5 days postpartum. One scale was kept firm exactly parallel to the ligament between the sacrum and the tuber ischii and other scale was erected perpendicularly to the first scale with the bottom just touching the ligament and the depth was measured in the second scale from the point where it touched the ligament to the point where it touched the first scale. Plasma samples were analyzed for E(1)S and E(2)beta by enzyme immunoassay. E(1)S concentration was low at day 100 (0.8+/-0.3 ng/ml), then increased progressively and drastically to reach the level of 28.4+/-3.6 ng/ml on the day before calving and declined significantly (p<0.05) at 9.5+/-3.1 ng/ml within 1 day postpartum. There was a gradual increase in concentration of E(2)beta from day 100 of gestation (0.1+/-0 ng/ml) until day 4 prepartum (0.6+/-0 ng/ml). Thereafter, it increased drastically and reached the peak level of 1.0+/-0.1 ng/ml (p<0.05) on the day before calving and declined markedly at 0.4+/-0.1 ng/ml within 1 day postpartum (p<0.05). Corresponding to E(1)S and E(2)beta concentrations, a gradual increase in the relaxation of the ligament was observed from day 100 of gestation (8+/-1mm) until day 2 prepartum (24+/-2mm). Thereafter, it showed a significant increase (p<0.05) within 1 day before calving (31+/-2mm) and almost no difference between day 1 prepartum and day 1 postpartum. A marked decrease (p<0.05) was observed thereafter until day 3 postpartum (10+/-2mm) and no significant change between days 3 and 4 as well as 4 and 5 postpartum. The increment of E(2)beta by >or=0.20 ng/ml from the preceding day concentration was 85.2% accurate for predicting calving within 24h in many of the cows (23 of 37) in the herd. The increment in ligament relaxation measurement by >or=5mm from the preceding day measurement was the most efficacious to predict calving within 24h with the highest accuracy (93.9%) in high proportions of cows (31 of 37) in the herd. In conclusion, plasma E(1)S and E(2)beta concentrations and relaxation of sacrosciatic ligament increased gradually as gestation advanced and reached the peak level on the day before calving. The relaxation in the ligament corresponded well to plasma E(2)beta concentrations. Prediction of calving was possible by E(2)beta profile and relaxation in the ligament but not by E(1)S profile. The increment in ligament measurement by >or=5mm from the preceding day measurement was the most useful and accurate in predicting calving within 24h. It is economical and easily applicable in the field condition.

Animals↗
PubMed2005

Survey of human exposure to PCDDs, PCDFs, and coplanar PCBs using hair as an indicator.

Our environment is polluted with toxic compounds including polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (Co-PCBs). We investigated the suitability of hair analysis for testing human exposure to toxic compounds. Hair analysis revealed that municipal solid-waste (MSW) incineration workers were exposed to PCDDs, PCDFs, and Co-PCBs at high levels. The total 2,3,7,8-TCDD toxic equivalent concentration in MSW incineration workers was 2.5 times higher than in the general population, thus indicating that the indoor environment of the incineration facility was more polluted than the general environment. There were also characteristic patterns of occurrence of these dioxin-like compounds in the hair of smokers from the general population. We confirmed that hair analysis is useful for evaluating human exposure to PCDDs, PCDFs, and Co-PCBs in the atmosphere.

Adult↗
PubMed2005

Enzyme immunoassay of progesterone in the feces from beef cattle to monitor the ovarian cycle.

The present study was undertaken to measure fecal progesterone concentration of beef cattle using antibody against authentic progesterone and to examine whether this method can monitor the ovarian cycle in beef cattle. Rectal fecal samples collected from 14 beef cattle were mixed with 6 ml of 100% methanol and shaken for 15 min. After centrifugation, supernatant was extracted with petroleum ether followed by an enzyme immunoassay (EIA) for progesterone. Specificity of the assay was examined by HPLC separation of fecal solution followed by the EIA in each fraction. The present assay identified only progesterone but not other metabolites in the feces sample that was extracted with petroleum ether. Sensitivity of the assay was estimated to be 0.0055 ng/ml (0.11 ng/g). Coefficient variations of intra- and inter-assay were 9.6-10.9% and 10.8-16.6%, respectively. Recovery rates ranged between 73 and 84%. Patterns in the fecal progesterone concentrations during the ovarian cycle were almost parallel to the plasma concentrations. A significant positive correlation was established between the fecal and plasma progesterone concentrations in individual animal (r=0.59-0.84, P<0.001, n=10) as well as pooled data (r=0.70, P<0.001, n=65). Fecal progesterone concentrations of day 0 (showing the nadir of concentration) of the ovarian cycle were less than 50 ng/g, which increased significantly toward day 9 (P<0.01). From days 14 to 18, there was significant reduction of fecal progesterone concentration (P<0.01). Ovarian cycles had at least 48 ng/g (mean=74 ng/g) of difference between minimum and maximum fecal progesterone concentrations. All cattle at days 9, 11 and 14 had higher fecal progesterone concentrations by more than 20 ng/g compared with day 0. These results suggest that the present EIA is suitable to measure the progesterone in cattle feces and can monitor ovarian cycle.

Animals↗
PubMed2005

Pregnancy diagnosis based on the fecal progesterone concentration in beef and dairy heifers and beef cows.

The present study was undertaken to examine whether pregnancy diagnosis was possible by measuring fecal progesterone concentrations in beef and dairy heifers and beef cows. Rectal fecal samples collected on days 18-24 after insemination or days 11-17 after embryo transfer were mixed with methanol and shaken for preparation of a fecal solution. After centrifugation, the supernatant was extracted with petroleum ether followed by an enzyme immunoassay for progesterone. All pregnant animals showed fecal progesterone concentrations greater than 50 ng/g of fecal material on days 18-24 after AI or estrus. In non-pregnant animals, however, the fecal progesterone concentrations ranged widely from 5 to 180 ng/g of fecal material. In non-pregnant cattle, the percentage of cattle with <50 ng progesterone/g of fecal material compared with the total number was 37-60% on days 18-20, whereas the percentages increased more than 70% to a maximum of 78.1% on day 23. When 50 ng/g was considered as the cut-off value, the sensitivity and specificity of positive pregnancy tests were less than 70% on days 21-24, and 100% for negative pregnancy tests on days 18-24. There were significant differences in the mean fecal progesterone concentrations between pregnant and non-pregnant cattle on days 19-24. These results suggest that feces can be utilized to substitute for plasma and milk to measure progesterone for the purpose of pregnancy diagnosis in heifers and cows.

Animals↗
PubMed2005

Apoptosis in the antral follicles of swamp buffalo and cattle ovary: TUNEL and caspase-3 histochemistry.

The present study was carried out to investigate the pattern of apoptosis in the healthy antral and atretic follicles of Philippine swamp buffaloes (BU) in comparison with Holstein-Friesian (HF) cows. Paraffin sections of healthy follicles and various stages of atretic follicles were stained using the terminal deoxynucleotidyl transferase (TdT)-mediated biotinylated deoxyuridine triphosphates (dUTP) nick end-labelling (TUNEL) method to detect DNA fragmentation and cleaved caspase-3 antibody to detect cells committed to undergo apoptosis. Five equidistant areas of a follicle were counted for the presence of TUNEL- and caspase-3-positive cells. Healthy follicles of BU and HF contained no TUNEL-positive cells in the granulosa and theca layer but showed some caspase-3 positivity. The granulosa layer of advanced atretic follicles showed a significantly higher frequency of caspase-3 positivity than the healthy and early atretic follicles in both breeds. The frequency of caspase-3-positive cells of BU was significantly higher than HF in the granulosa layer of healthy, early atretic and advanced atretic follicles. In the theca interna layer, BU and HF showed a significantly lower and higher frequency of TUNEL-positive cells in the late atretic follicles compared with advanced atretic follicle, respectively. However, the frequency of caspase-3-positive cells of both BU and HF in the late atretic follicles was significantly higher than the advanced atretic follicles in the theca interna layer. These results indicate that caspase-3 and DNA fragmentation is involved in the buffalo ovarian apoptotic process.

Animals↗
PubMed2005

Some characteristics of primary and secondary oestrous signs in high-producing dairy cows.

Shortened and weakened oestrous signs in dairy cows may cause a failure of oestrus detection and artificial insemination timing error leading to poor reproductive performance. The aims of this study were to investigate the duration of standing oestrus in high-producing dairy cows under a free stall system, to determine the duration of expression of secondary oestrous signs before and after standing oestrus (Expt 1) and to compare the duration and intensity of oestrus between cows and heifers (Expt 2). Cattle were checked for primary and secondary oestrous signs at an interval of 4 h. Heat detection aids were also used. In Expt 1, of 56 cows which were detected in oestrus, 36 cows (64.3%) showed standing oestrus and other 20 cows (36.6%) showed secondary oestrous signs only. Duration of the standing oestrus was 6.6 +/- 6.3 h on average (+/-SD), ranging between 2 and 32 h. The cows in standing oestrus showed secondary oestrous signs during a period from 9.6 +/- 8.1 h before onset of standing to 18.4 +/- 18.8 h after the end of standing oestrus. In the cows that did not show standing oestrus, expression of secondary oestrous signs were observed for 25.7 +/- 20.5 h, which was 7.5 h shorter than the average duration of oestrus in cows showing standing oestrus. In Expt 2, nine (82%) of the 11 lactating cows in oestrus showed standing, while all the 10 heifers exhibited standing oestrus. Average duration of standing oestrus was 6.4 +/- 4.3 h in cows and 6.2 +/- 3.9 h in heifers, respectively. It may be concluded that the duration of standing oestrus is substantially shortened in lactating dairy cows, and more than one-third of cows did not show standing oestrus. In cows showing standing oestrus, duration of expression of secondary oestrous signs before and after standing is not shortened. Duration of standing oestrus in heifers was as short as that in cows.

Animal Husbandry↗
PubMed2005

A case of novel de novo paired box gene 6 (PAX6) mutation with early-onset diabetes mellitus and aniridia.

BACKGROUND: Paired box gene 6 (PAX6) is a transcription factor involved in eye development. Mutations of PAX6 cause congenital eye anomalies, such as aniridia. PAX6 is also involved in the development of the endocrine pancreas, and reported to be a genetic factor common to aniridia and glucose intolerance, although the latter is usually mild. Here, we describe a case of PAX6 mutation with early-onset diabetes mellitus. CASE REPORT: A 27-year-old woman was referred to our clinic. She was diagnosed having diabetes at the age of 15 with negative glutamic acid decarboxylase (GAD) antibody. Insulin treatment was started at age 24. Because she had aniridia, PAX6 gene mutation was investigated and a heterozygous 2-bp deletion (c.402del2) was identified. Her parents did not have aniridia and PAX6 mutations. Heterozygous PAX6 mutation may cause glucose intolerance. However, cases of early-onset diabetes mellitus have not been reported. Her parents did not have diabetes, but their insulinogenic indices were low (0.25 and 0.3, respectively). We thought her early-onset diabetes was partly as a result of PAX6 mutation and partly because of an unknown insulin secretory defect inherited from her parents. We could not find any mutations in HNF-1alpha, -1beta, -4alpha, IPF-1, ISL-1, BEAT2/NeuroD1, PAX4, and amylin genes. CONCLUSIONS: We report a case of PAX6 gene mutation with early-onset diabetes mellitus and aniridia. Low insulin secretory capacity in her parents suggested that her insulin secretory defect is as a result of not only PAX6 mutation but other genetic factors inherited from her parents.

Adult↗
PubMed2004

Pregnancy diagnosis in miniature pig by direct ELISA of oestrone derivatives in faeces.

The objectives of the present study were to measure oestrone derivatives [oestrone, oestrone sulphate (E1S) and oestrone glucuronide] in sow faeces by direct enzyme-linked immunosorbent assay (ELISA) and to explore the changes of oestrone derivative profile in faeces of miniature pig for demonstrating the possibility of pregnancy diagnosis. Faecal samples (1.5 g) were put into 6 ml of buffer, shaken and centrifuged. Then supernatant was added to the wells of multi-plate without extraction and incubated with anti-oestrone antibody and horseradish peroxidase-labelled oestrone. Standard solution was prepared at various concentrations of E1S. Sensitivity was estimated as 0.035 ng/ml (0.14 ng/g). Intra- and inter-assay coefficient variations were 3.5-7.7% and 10.9-15.3%, respectively. When 1-5 ng/ml E1S were added to a faecal solution, recovery rates ranged between 80.0 and 103.3%. There is a temporal increase in the E1S equivalent concentration of miniature pig faeces from day 25 to 31 after mating. From day 35 to 70, the E1S equivalent concentrations remained low. Thereafter its concentrations increased again towards farrowing. On day 27 and 29 after mating pregnancy diagnosis by the faecal E1S equivalent concentrations agreed with the results of farrowing (seven of seven animals). These results suggest that the present direct ELISA is practical and suitable as a routine assay for measuring the faecal concentration of oestrone derivatives and that this assay might be usable for pregnancy diagnosis in sows at day 27-29.

Animals↗
PubMed2004

Cell proliferation in the atretic follicles of buffalo and cattle ovary.

The present study was carried out to describe the proliferative activity of granulosa and theca cells in healthy antral and atretic follicles of Philippine buffaloes (BU) and Holstein-Friesian (HF) cows. Paraffin sections of ovary were immunostained with mouse monoclonal antibody to proliferating cell nuclear antigen (PCNA). Then the follicles were classified into healthy and various stages of atretic follicles. The granulosa layer of healthy follicles had a significantly higher frequency of PCNA-positive cells than the early and advanced atretic follicles in both breeds. In the theca interna, significantly reduced populations of the PCNA-positive cells were found in both breeds as atresia progressed. Moreover, HF had significantly higher PCNA-positive cells in the theca interna of healthy, early atretic and advanced atretic follicles than BU. A reduction of PCNA-positive cells during atresia was also noted in the theca externa in both animals although differences were not significant. The results of the present work suggest that the proliferative activity of granulosa and theca cells decreases in association with follicular atresia in the BU similar to HF. Furthermore, a significantly deficient cell proliferative activity of theca interna was found in BU compared with HF.

Animals↗
PubMed2004

Incidence of silent ovulation in dairy cows during post partum period.

The present study was undertaken to show the incidence of silent ovulation in high producing dairy cows, by monitoring ovarian cyclicity based on practical milk progesterone assay which was established in this study. The direct milk progesterone enzyme linked immunosorbent assay (ELISA) was developed using anti-progesterone-3(E)-carboxymethyloxime-BSA antibody for the antibody and horse radish peroxidase labeled progesterone for tracer. High sensitivity (26 pg/mL, 0.65 pg/well), high recovery rates (83-97%), high reproducibility (CV of intra-assay 4.8-11.5%; CV of inter-assay 14.3-19.1%) and high correlation between milk progesterone concentrations measured by the direct ELISA and the values obtained by the ELISA after extraction proved the reliability of the assay. In second experiment the incidence of silent ovulation was investigated based on the milk progesterone concentrations in 32 dairy cows within 70 days post partum. The incidences of silent ovulation at the first, second, third and fourth ovulation post partum were 83, 46, 13 and 0%, respectively. Most commonly observed patterns of sequential occurrence of silent ovulation in cows ovulating 2, 3 or 4 times within 70 days post partum were silent-estrus (50%), silent-silent-estrus (60%) and silent-silent-estrus-estrus (67%), respectively. These results suggest that the present ELISA is a reliable and practically applicable method for determination of progesterone in milk and that high producing dairy cows show a high incidence of silent ovulation at the first post partum ovulation as well as the second ovulation, which then decreased with the increased frequency of ovulation.

Animals↗
PubMed2003

Distribution of cytochrome P450-side chain cleavage in the theca interna layers of bovine small antral and cystic follicles.

Cystic follicle is anovulatory follicular structure that is caused by an endocrine imbalance. The activity of cytochrome P450-side chain cleavage (P450scc) is essential for the initiation of steroidogenesis in the follicle. The present study was designed to compare the frequency of cells containing P450scc between healthy and atretic small antral follicles, and among several types (I, II and III, classified based on the presence of granulosa layer) of cystic follicles. Paraffin sections of healthy (2-5 mm in diameter), atretic (2-5 mm) and cystic follicles (>25 mm) were immunohistochemically stained with rabbit polyclonal antibody to bovine P450scc. The P450scc-positive cells were counted in four different regions of the follicles from the apical to the basal side. In small antral follicles and cystic follicles, P450scc-positive cells were localized in the theca interna layers but not granulosa layers. The P450scc-positive cell populations decreased in the late atretic follicles compared with the early and advanced atretic follicles at all the regions of follicle. Type III cystic follicles showed significantly lower frequencies of P450scc-positive cells than those in the types I and II cystic follicles. These results suggest that in both small and cystic follicles in cows, total loss of granulosa cells may be associated with the reduction of frequency of P450scc-positive cells in theca interna layer.

Animals↗
PubMed2001

Gene expression profiles for Fc epsilon RI, cytokines and chemokines upon Fc epsilon RI activation in human cultured mast cells derived from peripheral blood.

Mast cells have been reported to release not only chemical mediators, but also cytokines upon Fc epsilon receptor I(Fc epsilon RI) cross-linking. Recently, we have established a culture system to derive chymase-rich human mast cells from mononuclear cells in peripheral blood. However, the functional properties of these mast cells have remained unrevealed. In this study, we examined the functions of peripheral blood-derived human cultured mast cells (pHCMCs). pHCMCs expressed functional Fc epsilon RI, and most of them contained tryptase. These pHCMCs sensitized with immunoglobulin E (IgE) and interleukin 4 (IL-4) were activated through cross-linking of Fc epsilon RI. The time-dependent mRNA expression profiles of Fc epsilon RI subunits, cytokines and chemokines in the sensitized pHCMCs upon Fc epsilon RI engagement were examined by reverse transcriptase polymerase chain reaction (RT-PCR). mRNA for most of cytokines and chemokines, which were observed in allergic inflammation, was detected in activated pHCMCs. In addition, gene expression for monocyte chemoattractant protein 3 (MCP-3) in human mast cells, and liver and activation-regulated chemokine (LARC), thymus and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC) in mast cells was revealed for the first time in our study. Fc epsilon RI-mediated cytokine and chemokine production at protein level was evaluated using enzyme-linked immunosorbent assay (ELISA). These data suggest that pHCMCs, which are capable of producing a variety of cytokines and chemokines, can be a useful candidate for investigating roles of mast cells as a conductor for allergic inflammation.

Cells, Cultured↗