bluuebunny/crossref_metadata_2025 huggingface dataset:
Follicular Dynamics in Heifers during Pre‐pubertal and Pubertal Period Kept under Two Levels of Dietary Energy Intake
Authors: Romano MA , Barnabe VH , Kastelic JP , De Oliveira CA , Romano RM
Published: June 2007

Contents

The objective of this study was to characterize follicular dynamics in pre‐pubertal, pubertal and post‐pubertal periods, as well as the effect of high‐energy intake on follicular development and age at puberty in heifers. Thirty‐one Nelore (Bos indicus) heifers, 6 months old, were randomly assigned to receive two different diets: one of low (GI) and other of high dietary energy intake (GII). Animals were evaluated in relation to body weight gain by being weighed every 21 days. Heifers were evaluated every other day by real‐time linear ultrasonography to characterize ovarian structures development from weaning to post‐pubertal period. Blood samples were collected to determine plasmatic concentrations of progesterone by RIA method. The ovulation was determined when progesterone concentrations were >1 ng/mL in three consecutive samples, and by ultrasound images of corpus luteum; and oestrous behaviour in some animals. Age at puberty differed among heifers of GII (17.00 ± 0.46 months) compared with heifers of GI (19.87 ± 0.47 months; p ≤ 0.05). Maximum size of the dominant follicles at pre‐pubertal period was greater in GII heifers than in GI (10.52 ± 0.33 and 9.76 ± 0.15 mm, respectively; p ≤ 0.05). As heifers approached first ovulation time, size of dominant follicle increased (11.75 ± 0.37 mm for GI and 12.52 ± 0.91 mm for GII; p ≤ 0.05). Body weight at puberty was not different in both groups (302.33 ± 27.31 kg for GI and 326.19 ± 27.78 kg for GII heifers; p > 0.05). We conclude that animals receiving high dietary energy intake attained the puberty earlier and the development of follicles were different than in low dietary energy intake.
Cenomanian (Upper Cretaceous) carbon isotope stratigraphy of terrestrial organic matter for the Yezo Group, Hokkaido, Japan
Authors: Uramoto Go‐ichiro , Fujita Tomotaka , Takahashi Akinori , Hirano Hiromichi
Published: June 2007

Abstract  Carbon isotope fluctuations of sedimentary organic matter along the two geological traverses in the Yezo Group, Hokkaido, northern Japan, elucidate a detailed chemostratigraphy for the Cenomanian Stage on the northwestern Pacific margin. Visual characterization of the kerogen from mudstone samples shows that the major constituents of sedimentary organic matter originated as terrestrial higher plants. The atomic hydrogen/carbon ratios of the kerogen suggest that the original δ13C values of terrestrial organic matter (TOM) have not been affected significantly by thermal diagenesis. The patterns in two δ13CTOM curves are similar and independent of changes in lithology and total organic carbon contents, which suggests that TOM was mixed sufficiently before the deposition in the Yezo forearc basin for the δ13C composition having been homogenized. In addition, this implies that the Hokkaido δ13CTOM profiles represent the averaged temporal δ13C variations of terrestrial higher‐plant vegetation in the hinterlands of northeast Asia during Cenomanian time. Three shorter‐term (ca. 0.1 my duration) positive‐and‐negative δ13CTOM fluctuations of ∼1‰ are present in the Lower to Middle Cenomanian interval in the Yezo Group. On the basis of the age‐diagnostic taxa (ammonoids, inoceramids and planktic foraminifers), these discrete δ13CTOM events are interpreted to be correlated with those in the δ13C curves of pelagic carbonates from European basins. The correlation of δ13C events between the European and Yezo Group sections suggests that the shorter‐term δ13C fluctuations in Cenomanian ocean‐atmosphere carbon reservoirs are useful for global chemostratigraphic correlation of marine strata. In particular, the correlation of δ13C fluctuations of the so‐called ‘Mid‐Cenomanian event’ (MCE) implies: (i) the δ13C variations of global carbon reservoir during the MCE are precisely recorded in the δ13CTOM records; and (ii) the MCE δ13CTOM event is an efficient chronostratigraphic index for the Lower/Middle Cenomanian boundary of the Mid‐Cretaceous sequences.
Coxiella burnetii and acute exacerbations/infections in patients with chronic lung disease
Authors: OKIMOTO Niro , KIBAYASHI Takashi , MIMURA Kimihiro , YAMATO Kenji , KURIHARA Takeyuki , HONDA Yoshihiro , OSAKI Kohichi , ASAOKA Naoko , OHBA Hideo
Published: June 2007

The aim of the present study was to determine the incidence of Q fever in patients with an acute exacerbation of a chronic lower respiratory tract infection. Eighty patients treated for acute exacerbation of chronic lower respiratory tract infections during a 30‐month period were studied. Q fever was diagnosed by ELISA. Two elderly woman with pre‐existing bronchiectasis (2.5%) were diagnosed as having an acute infection by Coxiella burnetii. The acute illness was considered to be a result of mixed infection with Pseudomonas aeruginosa and Haemophilus influenzae with C. burnetii. Co‐infection with C. burnetii can occur during a bacterial exacerbation of a chronic lower respiratory tract infection.
Pleural fluid exchange in rabbits
Authors: STASHENKO Gregg J. , ROBICHAUX Amy , LEE Y.C. (Gary) , SANDERS Jonathan R. , ROSELLI Robert J. , LIGHT Richard W.
Published: June 2007

Background and objectives:  The study was designed to better characterize pleural fluid absorption in rabbits with the following two objectives: to determine the relative absorption of saline versus high‐protein solutions, and to identify the relative rates of absorption of dextran molecules of varying sizes.

Methods:  Twenty New Zealand white rabbits received a 12‐mL intrapleural injection of saline solution and a 10% protein solution on opposite sides, each solution containing dextran molecules with varying MWs. At sacrifice at 1, 4, 8, 18 and 24 h, the volume of pleural fluid and the concentrations of the dextran molecules were determined.

Results:  Saline was absorbed faster than the high‐protein fluid (P < 0.001). Dextran concentrations in the saline were significantly higher than those in the protein solution at all times after injection (P = 0.005; P < 0.001, respectively). The higher‐MW dextrans were cleared more slowly than the lower‐MW dextrans in a continuously graded manner.

Conclusions:  Saline was absorbed faster than a solution with a high protein content. There was a continuous spectrum in the rate of absorption of the dextran molecules, with the larger molecules being absorbed more slowly.
Effect of 1,25‐(OH)2D3 (a vitamin D analogue) on passively sensitized human airway smooth muscle cells
Authors: SONG Yingfang , QI Haowen , WU Changgui
Published: June 2007

Background and objectives:  In asthma, airway smooth muscle cell (ASMC) hyperplasia plays an important role in airway remodelling. Increased expression of matrix metalloproteinases‐9 (MMP‐9), a disintegrin and metalloprotease 33 (ADAM33) in ASMCs are also relevant to asthmatic airway remodelling. 1,25‐dihydroxyvitamin D3 (1,25‐(OH)2D3) has potent antiproliferative properties in vitro in various cell types; however, its role in ASMCs is not well understood. This study investigated the effect of 1,25‐(OH)2D3 on passively sensitized human bronchial (airway) smooth muscle cell (HASMC) proliferation and MMP‐9 and ADAM33 expressions.

Methods:  The effect of 1,25‐(OH)2D3 on cell proliferation was examined by 3‐(4,5‐dimethylthiazole‐2‐yl)‐2,5‐diphenyltetrazolium‐bromide colorimetry assay; cell cycle analysis by flow cytometry; and immunocytochemical staining for proliferating cell nuclear antigen (PCNA). The expression of MMP‐9 and ADAM33 in HASMCs was investigated by real‐time quantitative PCR and Western Blot analysis.

Results:  1,25‐(OH)2D3 effectively suppressed passively sensitized HASMC proliferation, proliferating cell nuclear antigen expression and G1/S transition in HASMCs passively sensitized with asthmatic serum. Further analysis showed that 1,25‐(OH)2D3 significantly down‐regulated the expressions of protein for MMP‐9 and ADAM33, as well as their mRNA levels in passively sensitized HASMCs.

Conclusions:  1,25‐(OH)2D3 has direct inhibitory effects on passively sensitized HASMCs in vitro, including inhibition of cell proliferation and expression of MMP‐9 and ADAM33, suggesting a possible beneficial role for 1,25‐(OH)2D3 in preventing and treating asthmatic airway remodelling.
The epidemiology of lymphangioleiomyomatosis in Japan: A nationwide cross‐sectional study of presenting features and prognostic factors
Authors: HAYASHIDA Mie , SEYAMA Kuniaki , INOUE Yoshikazu , FUJIMOTO Keisaku , KUBO Keishi ,   The Respiratory Failure Research Group of the Japanese Ministry of Health, Labor, and Welfare
Published: June 2007

Background and objective:  To evaluate the characteristics and prognostic factors of Japanese patients with lymphangioleiomyomatosis (LAM).

Methods:  A nationwide survey to identify patients with LAM was conducted by questionnaire. Survival probability was estimated using the Kaplan–Meier method, and the prognostic factors were analysed by Cox regression.

Results:  Data were collected on 173 patients with pulmonary LAM. The major presenting features were pneumothorax (43%) and exertional dyspnoea (37%). The survival probabilities for patients presenting with exertional dyspnoea (Group A) were 85%, 60% and 47% after 5, 10 and 15 years, respectively, and for patients presenting with pneumothorax (Group B) were 95%, 89% and 89%, respectively. Although the age at symptom onset was higher among patients in Group A than in Group B, Cox regression revealed that the presenting feature was a prognostic factor independent of age at symptom onset (Group A/B hazard ratio = 5.732, P < 0.01). In the subgroup of patients whose initial FEV1 was >1000 mL, or FEV1/FVC >40%, or %DLCO >40%, the rate of deterioration in these tests was greater in Group A than in Group B (P < 0.01 for FEV1, P < 0.05 for FEV1/FVC and %DLCO).

Conclusions:  There are two possible subgroups of LAM patients. One subgroup that presented with pneumothorax, had onset of symptoms at a younger age and a more favourable prognosis; the other presented with exertional dyspnoea, had onset of symptoms at an older age and a poorer prognosis.
Pediatricians’ satisfaction with their abilities to care for children with developmental, behavioral and psychosocial problems
Authors: SENECKY YEHUDA , INBAR DOV , DIAMOND GARY , GROSSMAN ZACHI , APTER ALAN , KAHAN ERNESTO
Published: June 2007

Background: Developmental and behavioral pediatrics has emerged as an area of special interest and new responsibility for pediatricians. The aim of this study was to evaluate the impact of training, experience, and other factors on pediatricians’ satisfaction with their abilities to care for children with developmental, behavioral and psychosocial problems.

Methods: A questionnaire was sent to 211 pediatricians working in primary care clinics in the community in Israel. Items included personal characteristics and experience, practice and satisfaction with the care of children with developmental, behavioral and psychosocial problems. Overall, pediatrician satisfaction with their personal abilities in this domain was defined as the dependent variable on multivariate analysis.

Results: The response rate was 76.3% (n = 161). Pediatricians’ satisfaction with their overall professional ability to care for children with developmental, behavioral and psychosocial problems was significantly and positively associated with the following independent variables: (i) satisfaction with training received in the child development field; (ii) satisfaction with psychiatric updates; (iii) general satisfaction with the available child development services; (iv) prescription of methylphenidate to children with attention deficit/hyperactivity disorder; and (v) having completed their medical studies in a country in which the issue is emphasized.

Conclusions: Imparting more knowledge and skills in child development and behavioral pediatrics in pediatric residency and continuing education programs will help improve the attitudes of primary care pediatricians towards developmental and behavioral problems, encourage them to treat these patients and their families, and better the quality of care.
Growth of patients with congenital hypothyroidism detected by neonatal screening in Japan
Authors: SATO HIROKAZU , SASAKI NOZOMU , AOKI KIKUMARO , KURODA YASUHIRO , KATO TADAAKI
Published: June 2007

Background: The growth of patients with congenital hypothyroidism detected by neonatal screening in Japan was investigated. The data investigated were obtained from Medical Aid Program for Chronic Pediatric Diseases of Specified Categories registered in 2002.

Method: The present study included 2341 patients (1030 male, 1311 female) registered as having congenital hypothyroidism. To investigate the growth of these patients, their heights plotted on cross‐sectional growth charts for boys and girls, their bodyweights expressed as percentage of bodyweight for height and the frequency distribution of percentage of bodyweight for height were assessed.

Results: Cross‐sectional growth charts of both male and female patients showed that the heights of the majority of the patients with congenital hypothyroidism were within ±2SD. Approximately half of the patients with heights below −2SD, had some complications. The mean percentages of ideal bodyweights for height were 103.0 ± 12.9% for both sexes (±SD, n = 2033), 103.3 ± 12.7% for boys, and 102.7 ± 12.9% for girls. The frequency distribution of percentage of bodyweight showed no tendency of shifting to either ends in comparison with normal distribution curve.

Conclusion: Patients with congenital hypothyroidism detected by neonatal screening had normal growth in general, suggesting that the neonatal screening system is being performed efficiently from detection to treatment of the disease in Japan. However, it remains unclear whether some uncomplicated patients with a height below −2 SD are sufficiently treated or not. Close observation of these patients may be needed.
Three mutations analysis of glucose‐6‐phosphate dehydrogenase deficiency in neonates in South‐west China
Authors: DENG CHUN , GUO CHUN‐BAO , XU YOU‐HUA , DENG BING , YU JIA‐LIN
Published: June 2007

Background: Glucose‐6‐phosphate dehydrogenase (G6PD) deficiency, one of the most common human enzymatic defects, is characterized by extreme molecular and biochemical heterogeneity. The underlying DNA changes associated with G6PD deficiency in Asian subjects have not been extensively investigated.

Methods: Three gene mutations (G1388A, G1376T, A95G, corresponding amino acid change: Arg463His, Arg459Leu, His32Arg, respectively) were examined in 240 G6PD‐deficient subjects originating from South‐west China using specific polymerase chain reaction.

Results: Of the 240 patients with G6PD deficiency, 190 were found to have the G1388A mutation, 48 had G1376T and two had A95G. There were no significant differences between the clinical manifestations caused by the former two gene mutations, which both cause acute hemolytic anemia and jaundice. Therefore the most common gene mutations of G6PD deficiency in neonates in South‐west China are G1388A and G1376T mutations.

Conclusion: It is suggested that G6PD deficiency screening be done in higher risk neonates with jaundice in qualified hospitals as soon as possible.
Is childhood asthma still underdiagnosed and undertreated in Istanbul?
Authors: KARADAG BULENT , KARAKOC FAZILET , ERSU REFIKA , DAGLI ELIF
Published: June 2007

Background: Childhood asthma is reported to be underdiagnosed and undertreated worldwide. The purpose of the present study was to investigate the rate of underdiagnosis and undertreatment among children diagnosed with asthma in a tertiary reference center in Turkey.

Methods: A questionnaire survey was carried out among the parents of 1134 patients diagnosed with asthma in a tertiary reference outpatient clinic.

Results: Mean age of the patients was 4.9 years (range 1–17 years). Of these children 45.5% had recurrent asthma attacks (average 4.8 attacks per year) and 24.7% had only the symptom of vigorous fits of coughing. Although they had been symptomatic for 29.6 months, only 41.1% were diagnosed as having asthma before admission to the clinic. In this study group 61.3% had received some form of asthma treatment, but only 21.1% of all patients were treated according to the guidelines. The rate of treatment according to guidelines was lower in the children under 6 years of age than older children (18.8 vs 24.2%, respectively, P  = 0.02).

Conclusions: Underdiagnosis and undertreatment of childhood asthma still seem to be a major problem in the management of childhood asthma, especially in preschool children, even after the recommendations of guidelines.
Permanent prostate brachytherapy for Japanese men: Results from initial 100 patients with prostate cancer
Authors: Okaneya Toshikazu , Nishizawa Shuji , Nakayama Tsuyoshi , Kamigaito Takayuki , Hashida Iwao , Hosaka Noriko
Published: June 2007

Objective:  To evaluate the initial results of brachytherapy for prostate cancer with permanent iodine‐125 implant in Japan.

Methods:  The results obtained with brachytherapy in the initial 100 Japanese patients treated at Nagano Municipal Hospital were reviewed. Patients with a prostate‐specific antigen (PSA) level of less than 10 ng/mL and a Gleason's scores of 5, 6, 3 + 4 were classified as having a low risk of recurrence. Patients with a PSA level of 10–20 ng/mL and/or a Gleason's score of 4 + 3 were classified as having an intermediate risk for recurrence. Seventy‐eight of the low‐risk patients and 19 of the intermediate‐risk patients were treated by seed implants alone, or seed implants combined with preceding external radiation, respectively. A total of 53 patients received neoadjuvant hormone therapy. The efficacy and morbidity of brachytherapy were investigated using the serum PSA, International Prostate Symptom Score, quality of life score and uroflowmetry data.

Results:  The average V100 and D90 obtained by post‐implant dosimetry was 94.3 and 113.7%, respectively. Serum PSA decreased gradually after treatment, although it had still not reached a nadir after 1 year. There was little difference of the PSA level between the patients with and without neoadjuvant hormone therapy even at 1 year after seed implantation. There were no PSA biochemical failure or clinical recurrence during the follow‐up period. Voiding symptoms worsened until 3 months after treatment, and then gradually improved. Acute urinary retention occurred transiently in one patient (1%). Rectal bleeding and severe diarrhea did not occur.

Conclusion:  Brachytherapy is a feasible and effective option for the treatment of prostate cancer in Japanese men. Brachytherapy may have a different effect in Japanese patients with respect to voiding symptoms. Urinary retention was rare, but voiding symptoms were persistent in Japanese patients. Neoadjuvant hormone therapy deserves investigation to determine whether it can achieve better results, especially in patients with an intermediate risk.
Urinary concentration of osteopontin and association with urinary supersaturation and crystal formation
Authors: Tsuji Hidenori , Tohru Umekawa , Hirotsugu Uemura , Masanori Iguchi , Yuji Hatanaka , Takashi Kurita
Published: June 2007

Objective:  In this study, we measured urinary osteopontin (OPN) concentrations in urolithiasis patients as well as in healthy volunteers, and investigated the relationship between urinary excretion of OPN and urinary supersaturation level.

Methods:  Supersaturation levels (AP indexes) were determined by using Tiselius's index. Crystals with a maximum diameter of 12 ìm or larger and less than 5 ìm were counted by scanning electron microscopy. A sum of cross‐sectional areas of crystals was also calculated as the total crystal volume (VT).

Results:  Urinary OPN concentrations in the group with no urinary stone were significantly higher than that in the urolithiasis patients with a tendency toward stone enlargement. AP indexes were observed to be significantly higher in patients with stone enlargement, whereas urinary OPN concentrations bore no definite relation to the urinary supersaturation levels. VT and number of large crystals (12 ìm or larger) in patients with a tendency toward stone enlargement were higher than healthy volunteers, but no differences were found between the number of micro‐crystal with the diameter of less than 5 ìm. On the basis of the plots of VT and OPN concentrations, regression analysis revealed that VT and log OPN had a significant correlation.

Conclusion:  Urinary OPN tended to be lower in cases with larger crystal volumes and is potentially associated with crystal growth for inhibitory effect.
Overactive bladder and glaucoma: A survey at outpatient clinics in Japan
Authors: Kato Kumiko , Furuhashi Kenichi , Suzuki Koichi , Murase Tatsuro , Sato Etsuko , Gotoh Momokazu
Published: June 2007

Objective:  To determine the prevalence of a history of glaucoma and the relative safety of prescribing anticholinergics to patients with overactive bladder (OAB).

Methods:  Between 2003 and 2005, 267 female OAB patients (mean age, 65.8 years) and 100 male OAB patients (mean age, 73.0 years) were directly asked about their history of glaucoma. Those with a positive history were referred to ophthalmologists to differentiate types of glaucoma.

Results:  For direct history taking, 31 (11.6%) of the female OAB patients and five (5.0%) of the male OAB patients admitted their history of glaucoma. Referrals to ophthalmologists revealed that 27 had open‐angle glaucoma and nine had angle‐closure glaucoma. Six of the patients with angle‐closure glaucoma had already received laser iridotomy, and the remaining three (8.3% of patients with coexisting glaucoma) were diagnosed as true contraindications for anticholinergics.

Conclusions:  As both OAB and glaucoma increase with age, it is not surprising that approximately 10% of OAB patients have glaucoma. Although the majority have had either open‐angle glaucoma or angle‐closure glaucoma already treated, some of them may be true contraindications for anticholinergics due to uncontrolled angle‐closure glaucoma. It seems necessary to treat OAB patients based on accurate information on the relationship between glaucoma and anticholinergics.
Crack tip displacements of microstructurally small cracks in 316L steel and their dependence on crystallographic orientations of grains
Authors: SIMONOVSKI I. , NILSSON KARL‐FREDRIK , CIZELJ L.
Published: June 2007

The paper presents an analysis of the effect of the grain orientations on a short Stage I surface crack in a 316L stainless steel. The analysis is based on a plane‐strain finite element crystal plasticity model. The model consists of 212 randomly shaped, sized and oriented grains that is loaded monotonically in uniaxial tension to a maximum load of 1.12Rp0.2 (280 MPa). The influence of random grain structure on a crack is assessed by calculating the crack tip opening (CTOD) and sliding displacements (CTSD) for single crystal and polycrystal models, considering also different crystallographic orientations. In the single crystal case the CTOD and CTSD may differ by more than one order of magnitude. Near the crack tip slip is activated on all the slip planes whereby only two are active in the rest of the model. The maximum CTOD is directly related to the largest Schmid factors. For the more complex polycrystal cases it is shown that certain crystallographic orientations result in a cluster of soft grains around the crack‐containing grain. In these cases the crack tip can become a part of the localized strain, resulting in a large CTOD value. This effect, resulting from the overall grain orientations and sizes, can have a greater impact on the CTOD than the local grain orientation. On the other hand, when a localized soft response is formed away from the crack, the localized strain does not affect the crack tip directly, resulting in a small CTOD value. The resulting difference in CTOD can be up to a factor of 4, depending upon the crystallographic set. Grains as far as 6xCracklength significantly influence the crack tip parameters. It was also found that among grains with favourable orientation the CTOD increased with the size of such a grain. Finally, a significant change in CTOD and CTSD was observed when extending the crack into the second grain and placing it in the primary or the conjugate slip plane.
Experimental investigations on the growth of small fatigue cracks in naval steel
Authors: ELMALKI ALAOUI A. , THEVENET D. , ZEGHLOUL A.
Published: June 2007

The concept of damage tolerance is now largely employed to evaluate the fatigue life of structures. However, part of this fatigue relies on the initiation and growth of small cracks. The fatigue behaviour of a naval structural steel (S355NL) was investigated. In order to characterize the behaviour of short and long cracks, tests were performed under constant amplitude loading for several load ratios between –1.0 and 0.5. A major part of fatigue life is constituted by short crack initiation and propagation.
Investigation of small crack behaviour under cyclic loading in a dual phase steel with an FIB tomography technique
Authors: MOTOYASHIKI Y. , BRÜCKNER‐FOIT A. , SUGETA A.
Published: June 2007

Damage accumulation is investigated in the early stage of fatigue life in a ferritic martensitic dual phase steel. Microcrack initiation and propagation are influenced by microstructure, such as grain boundaries, grain orientation and/or phase distribution morphology. The dominant crack initiation pattern is one in which microcracks are generated in a ferrite grain along slip bands inclined at a certain angle with respect to the loading direction. Subsurface observation with a focused ion beam (FIB) device and additional crystallographic characterization by means of the electron backscatter diffraction (EBSD) technique show that a slip system having a high Schmid factor value is activated and results in a crack nucleus. The FIB tomography technique with the help of EBSD measurement allows a three‐dimensional investigation of small crack behaviour to be performed.
A new methodology to guarantee the structural integrity of Al2O3/SiC composite using crack healing and a proof test
Authors: ONO M. , NAKAO W. , TAKAHASHI K. , NAKATANI M. , ANDO K.
Published: June 2007

Structural ceramics are brittle and sensitive to flaws. As a result, the structural integrity of a ceramic component may be seriously affected by inherent flaws. Self‐crack‐healing is an excellent answer to this problem. At the moment, however, there is no technique to heal embedded flaws. Therefore, a technique to guarantee the reliability of ceramic components is demanded, and thus a technique using crack healing followed by proof test was developed by K. Ando et al. to accomplish this. With this technique, testing the mechanical behaviour of the crack‐healed zone is very important for ensuring the structural integrity of a ceramic component. In this study, first Al2O3/SiC composite with an excellent crack‐healing ability was sintered. Second, a crack was introduced on the sample (3 mm × 4 mm × 36 mm), which reduced the bending strength by about 80%, and subsequently the crack was healed. Third, a proof test was carried out on the crack‐healed sample. Last, using the crack‐healed and proof‐tested sample, a fracture test was carried out up to 1373 K. The measured minimum fracture stress (σFmin) was compared with the theoretical minimum strength (σG) from room temperature (R.T.) to 1373 K. It was concluded that σG showed good agreement with σFmin up to 1373 K and that the crack healing followed by proof test was an excellent technique to increase the survival probability by administering a proof test and to guarantee the reliability of Al2O3/SiC composite.
Properties of paired‐pulse firing thresholds and the relationship with paired‐pulse plasticity in hippocampal CA3–CA1 synapses
Authors: Huang Fen‐Sheng , Meng Kai , Tang Jing‐Shi
Published: June 2007

A large variability of paired‐pulse plasticity (PPP) has been reported in CA3–CA1 synapses, and paired‐pulse facilitation (PPF) has long been extensively used as a relative index of release probability (Pr) from the presynaptic terminal. One of the most common ways of studying Pr and PPP is to pass paired‐pulse stimulation (PPS) through an electrode to fire an action potential (AP), which in turn opens Ca2+ channels in the presynaptic boutons to evoke transmitter release. However, when the postsynaptic responses were elicited by electrical stimulations, the presynaptic APs were usually not monitored. The reliability of presynaptic activation, the difference of AP firing thresholds between the first and the second pulses of PPS, and its relationship with Pr and PPP have been largely ignored. Here we show that the AP firing thresholds in the same CA3 pyramidal cells (axons) are obviously lower for the second pulses of the PPS than for the first pulses. When single (or small numbers of) presynaptic axons were stimulated by low‐intensity PPS, a large variation in the postsynaptic response probability of the first pulses (Pres1) and PPP was observed. Increasing stimulation intensities resulted in the conversion of a lower Pres1 and PPF to a higher Pres1 and paired‐pulse depression. These results indicate that changes in the reliability of AP initiation by the first pulse of the PPS may account for the high variability of Pres1 and PPP observed in CA1 pyramidal cells of the hippocampus, therefore PPF may not be a reliable index of Pr .
Reorganization of GABAergic circuits maintains GABAA receptor‐mediated transmission onto CA1 interneurons in α1‐subunit‐null mice
Authors: Schneider Gasser Edith M. , Duveau Venceslas , Prenosil George A. , Fritschy Jean‐Marc
Published: June 2007

The majority of hippocampal interneurons strongly express GABAA receptors containing the α1 subunit, suggesting that inhibitory control of interneurons is important for proper function of hippocampal circuits. Here, we investigated with immunohistochemical and electrophysiological techniques how these GABAA receptors are replaced in mice carrying a targeted deletion of the α1‐subunit gene (α10/0 mice). Using markers of five major populations of CA1 interneurons (parvalbumin, calretinin, calbindin, neuropeptide Y and somatostatin), we show that these interneurons remain unaffected in α10/0 mice. In triple immunofluorescence staining experiments combining these markers with the GABAA receptor α1, α2 or α3 subunit and gephyrin, we demonstrate a strong increase in α3‐ and α2‐GABAA receptors clustered at postsynaptic sites along with gephyrin in most CA1 interneurons in α10/0 mice. The changes were cell type‐specific and resulted in an increased number of GABAergic synapses on interneurons. These adjustments were mirrored functionally by retention of spontaneous IPSCs with prolonged decay kinetics, as shown by whole‐cell patch‐clamp recordings of CA1 interneurons. However, a significant decrease in frequency and amplitude of miniature IPSCs was evident, suggesting reduced affinity of postsynaptic receptors and/or impaired vesicular GABA release. Finally, to assess whether these compensatory changes are sufficient to protect against a pathological challenge, we tested the susceptibility of α10/0 mice against kainic acid‐induced excitotoxicity. No genotype difference was observed in the effects of kainic acid, indicating that the absence of a major GABAA receptor subtype is functionally compensated for in hippocampal interneurons by a reorganization of inhibitory circuits.
Small‐world network topology of hippocampal neuronal network is lost, in an in vitro glutamate injury model of epilepsy
Authors: Srinivas Kalyan V. , Jain Rishabh , Saurav Subit , Sikdar Sujit K.
Published: June 2007

Neuronal network topologies and connectivity patterns were explored in control and glutamate‐injured hippocampal neuronal networks, cultured on planar multielectrode arrays. Spontaneous activity was characterized by brief episodes of synchronous firing at many sites in the array (network bursts). During such assembly activity, maximum numbers of neurons are known to interact in the network. After brief glutamate exposure followed by recovery, neuronal networks became hypersynchronous and fired network bursts at higher frequency. Connectivity maps were constructed to understand how neurons communicate during a network burst. These maps were obtained by analysing the spike trains using cross‐covariance analysis and graph theory methods. Analysis of degree distribution, which is a measure of direct connections between electrodes in a neuronal network, showed exponential and Gaussian distributions in control and glutamate‐injured networks, respectively. Although both the networks showed random features, small‐world properties in these networks were different. These results suggest that functional two‐dimensional neuronal networks in vitro are not scale‐free. After brief exposure to glutamate, normal hippocampal neuronal networks became hyperexcitable and fired a larger number of network bursts with altered network topology. The small‐world network property was lost and this was accompanied by a change from an exponential to a Gaussian network.
Disruption of reelin signaling attenuates methamphetamine‐induced hyperlocomotion
Authors: Matsuzaki Hideo , Minabe Yoshio , Nakamura Kazuhiko , Suzuki Katsuaki , Iwata Yasuhide , Sekine Yoshimoto , Tsuchiya Kenji J. , Sugihara Genichi , Suda Shiro , Takei Nori , Nakahara Daiichiro , Hashimoto Kenji , Nairn Angus C. , Mori Norio , Sato Kohji
Published: June 2007

To clarify whether reelin signaling is involved in dopaminergic neurotransmission in the adult mouse brain, we investigated dopamine function in mice lacking reelin (reeler). We found that methamphetamine‐induced locomotor activity is significantly attenuated in reeler mice. To elucidate the mechanism of this phenomenon, we first investigated presynaptic dopamine release; however, there were no significant differences in wildtype, heterozygous reeler and homozygous reeler mice. Next, we examined the locomotor response to intra‐accumbens injection of dopamine D1 and D2 receptor agonists, and found that lack of reelin signaling results in decreases in both D1 and D2 receptor‐mediated dopaminergic functions. In addition, we measured dopamine receptor binding in the striatum, and found that both D1 and D2 classes of dopamine receptors are reduced in reeler mice. Furthermore, we found that the phosphorylation levels of DARPP‐32 are also changed by lack of reelin signaling. Finally, to distinguish between a developmental role of reelin or an acute role of reelin in adult mouse, we intraventricularly infused CR‐50, a monoclonal antibody against reelin. Interestingly, infusion of CR‐50 also significantly reduced methamphetamine‐induced hyperlocomotion in wildtype mice, showing that reelin has an acute role in the dopaminergic system. These results indicate that reelin signaling plays a pivotal role in the dopaminergic system in adult mice, especially in postsynaptic levels.
Brainstem cholinergic modulation of muscle tone in infant rats
Authors: Gall Andrew J. , Poremba Amy , Blumberg Mark S.
Published: June 2007

In week‐old rats, lesions of the dorsolateral pontine tegmentum (DLPT) and nucleus pontis oralis (PnO) have opposing effects on nuchal muscle tone. Specifically, pups with DLPT lesions exhibit prolonged bouts of nuchal muscle atonia (indicative of sleep) and pups with PnO lesions exhibit prolonged bouts of high nuchal muscle tone (indicative of wakefulness). Here we test the hypothesis that nuchal muscle tone is modulated, at least in part, by cholinergically mediated interactions between these two regions. First, in unanesthetized pups, we found that chemical infusion of the cholinergic agonist carbachol (22 mm, 0.1 µL) within the DLPT produced high muscle tone. Next, chemical lesions of the PnO were used to produce a chronic state of high nuchal muscle tone, at which time the cholinergic antagonist scopolamine (10 mm, 0.1 µL) was infused into the DLPT. Scopolamine effectively decreased nuchal muscle tone, thus suggesting that lesions of the PnO increase muscle tone via cholinergic activation of the DLPT. Using 2‐deoxyglucose autoradiography, metabolic activation throughout the DLPT was observed after PnO lesions. Finally, consistent with the hypothesis that PnO inactivation produces high muscle tone, infusion of the sodium channel blocker lidocaine (2%) into the PnO of unanesthetized pups produced rapid increases in muscle tone. We conclude that, even early in infancy, the DLPT is critically involved in the regulation of muscle tone and behavioral state, and that its activity is modulated by a cholinergic mechanism that is directly or indirectly controlled by the PnO.
Group I metabotropic glutamate receptors enable two distinct forms of long‐term depression in the rat dentate gyrusin vivo
Authors: Naie Katja , Tsanov Marian , Manahan‐Vaughan Denise
Published: June 2007

The existence of long‐term depression (LTD) in the dentate gyrus of freely moving rats, as well as the contribution of different types of metabotropic glutamate receptors (mGluRs) to this form of plasticity, has been the subject of much debate. Here, we describe two distinct forms of mGluR‐dependent hippocampal LTD in the dentate gyrus of freely moving adult rats. LTD, induced by low‐frequency stimulation (LFS) of the medial perforant path (LFS‐LTD), was prevented by antagonism of the phospholipase C‐coupled receptors, mGluR1 but not mGluR5. Chemical LTD, induced by intracerebral application of the group I mGluR agonist (R,S)‐3,5‐dihydroxyphenylglycine, was blocked by antagonism of both mGluR5 and mGluR1. Selective activation of mGluR5, using (R,S)‐2‐chloro‐5‐hydroxyphenylglycine (CHPG), also led to chemical LTD. To test whether LFS‐LTD and chemical LTD share common induction mechanisms, we applied LFS following the induction of chemical LTD by CHPG (CHPG‐LTD). Surprisingly, LFS impaired CHPG‐LTD. Further analysis revealed that induction of CHPG‐LTD led to altered calcium dynamics sufficient for its reversal by LFS. We found that LTD induced by (R,S)‐3,5‐dihydroxyphenylglycine, but not by CHPG, is impaired byN‐methyl‐d‐aspartate receptor antagonism. Both forms of chemical LTD strongly require calcium influx throughL‐type voltage‐gated calcium channels. This contrasts with previous findings that LFS‐LTD in the dentate gyrus is bothN‐methyl‐d‐aspartate receptor and voltage‐gated calcium channel independent. LFS‐LTD and LTD induced by group I mGluR agonists thus appear to comprise distinct forms of LTD that require the activation of specific group I mGluRs and recruit calcium from different sources.
Individual differences in the effects of chronic prazosin hydrochloride treatment on hippocampal mineralocorticoid and glucocorticoid receptors
Authors: Kabbaj Mohamed , Morley‐Fletcher Sara , Le Moal Michel , Maccari Stefania
Published: June 2007

The aim of this study was to investigate the noradrenergic regulation of mineralocorticoid receptors (MRs) and glucocorticoid receptors (GRs) in high responder (HR) and low responder (LR) male rats, an animal model of individual differences in hypothalamo‐pituitary‐adrenal axis activity and vulnerability to drugs of abuse. The effects of a chronic treatment with the noradrenergic α1 antagonist (1‐[4‐amino‐6,7‐dimethoxy‐2‐quinazolinyl]‐4‐[2‐furanylcarbonyl] piperazine) hydrochloride (prazosin) (0.5 mg/kg, i.p., 35 days) were assessed on stress‐induced corticosterone (CORT) secretion and on hippocampal MRs and GRs in adrenally intact rats. In order to ascertain whether the effects of chronic prazosin treatment on hippocampal MRs and GRs were direct or indirect, through prazosin‐induced CORT secretion, we also assessed the effects of the same treatment on adrenalectomized rats with CORT substitutive therapy. When compared with LR rats, HR rats exhibited a delayed return to the basal level of CORT following acute restraint stress; this was associated with a lower binding of MRs and GRs in HR rats than in LR rats. Chronic prazosin treatment had no effect in HR animals but markedly reduced hippocampal MRs and GRs, and increased stress‐induced CORT secretion in LR rats. In LR adrenalectomized rats, prazosin reduced hipppocampal MRs but did not change GRs. Our results provide evidence of a differential regulation by noradrenaline of hippocampal MRs and GRs in HR and LR rats. These data could have clinical implications in terms of individual differences in the resistance to antidepressant treatments and individual differences in drug abuse.
No improvement by amphetamine on learned non‐use, attempts, success or movement in skilled reaching by the rat after motor cortex stroke
Authors: Alaverdashvili Mariam , Lim Diana H. , Whishaw Ian Q.
Published: June 2007

Amphetamine (AMPH) has been proposed as a treatment for post‐stroke motor deficits when coupled with symptom‐relevant physical rehabilitation. Whereas a number of experimental studies report improvements in endpoint measures of skilled reaching for food by rats, there has been no assessment of whether beneficial effects extend to overcoming learned non‐use of the limb in the acute post‐stroke period or to the qualitative deficits in movement in the chronic post‐stroke period. In addition to evaluating the effects of AMPH on success, these were the objectives of the present study. In three different reaching experiments, groups of rats were pre‐trained in skilled reaching for food prior to receiving a motor cortex stroke via pial removal. Postoperatively the rats received periodic AMPH treatment and daily rehabilitation. In the acute post‐stroke period, AMPH failed to prevent the development of learned non‐use of the limb, and in the acute and chronic period failed to improve recovery of reaching success, and also failed to improve the qualitative aspects of reaching movements. Nevertheless, AMPH did enhance adjunct non‐reaching movements of locomotion, rearing and turning. The results are discussed in relation to the idea that the beneficial effects of post‐stroke AMPH treatment do not extend to all movements, especially the movements of a forelimb in retrieving and consuming food.
Decreased motivation to eat in µ‐opioid receptor‐deficient mice
Authors: Papaleo Francesco , Kieffer Brigitte L. , Tabarin Antoine , Contarino Angelo
Published: June 2007

Altered motivational processes might participate to the physiopathology of eating‐related disorders. The endogenous opioid system is thought to mediate the hedonic properties of food intake. To assess the role for the µ‐opioid receptor (MOR) pathway in the motivational properties of food intake, in the present study we tested wild‐type and MOR‐deficient mice (MOR–/–) in a nose‐poke operant paradigm for chow or sucrose pellets. To avoid confounding factors linked to food restriction/deprivation experience, mice were always provided with foodad libitum. Although less MOR–/– than wild‐type mice initiated operant behaviour, under a fixed ratio‐1 (FR‐1) reinforcement schedule the two genotypes showed similar patterns of food‐driven nose‐poking, indicating preserved cognitive abilities in MOR‐deficient mice. However, during FR‐3 and progressive ratio (PR) reinforcement experiments, MOR–/– mice showed lower levels of nose‐poking for either chow or sucrose pellets than wild‐type mice, indicating a crucial role for the MOR pathway in the motivational properties of food intake. Moreover, under the PR reinforcement schedule mice nose‐poking for sucrose pellets showed higher genotype‐independent breakpoint levels than mice working for chow pellets, indicating that the MOR pathway is not essential for hedonic processing of palatable food intake. Finally, MOR–/– mice did not differ from wild‐type mice in the rate of operant responding extinction, further supporting the notion of unaltered cognitive abilities in the MOR‐deficient mice. The present findings strongly indicate that the MOR pathway mediates the motivational properties of food intake, but it is not essential for hedonic processing of ingestive behaviour.
Role of the midbrain dopaminergic system in modulation of vocal brain activation by social context
Authors: Hara Erina , Kubikova Lubica , Hessler Neal A. , Jarvis Erich D.
Published: June 2007

In a well‐studied model of social behaviour, male zebra finches sing directed song to court females and undirected song, used possibly for practice or advertisement. Although the two song types are similar, the level of neural activity and expression of the immediate early geneegr‐1are higher during undirected than during directed singing in the lateral part of the basal ganglia song nucleus AreaX (LAreaX) and its efferent pallial song nuclei lateral magnocellular nucleus of the anterior nidopallium (LMAN) and the robust nucleus of the arcopallium (RA). As social interactions are dependent on brain motivation systems, here we test the hypothesis that the midbrain ventral tegmental area–substantia nigra pars compacta (VTA–SNc) complex, which provides a strong dopaminergic input to LAreaX, is a source of this modulation. Usingegr‐1expression, we show that GABAergic interneurons in VTA–SNc are more active during directed courtship singing than during undirected singing. We also found that unilateral removal of VTA–SNc input reduced singing‐dependent gene expression in ipsilateral LAreaX during both social contexts but it did not eliminate social context differences in LAreaX. In contrast, such lesions reduced and eliminated the social context differences in efferent nuclei LMAN and RA, respectively. These results suggest that VTA–SNc is not solely responsible for the social context gene regulation in LAreaX, but that VTA–SNc input to LAreaX enhances the singing‐regulated gene expression in this nucleus and, either through LAreaX or through direct projections to LMAN and RA, VTA–SNc is necessary for context‐dependent gene regulation in these efferent nuclei.
Disgust sensitivity predicts the insula and pallidal response to pictures of disgusting foods
Authors: Calder Andrew J. , Beaver John D. , Davis Matt H. , Van Ditzhuijzen Jenneke , Keane Jill , Lawrence Andrew D.
Published: June 2007

The anterior insula has been implicated in coding disgust from facial, pictorial and olfactory cues, and in the experience of this emotion. Personality research has shown considerable variation in individuals' trait propensity to experience disgust (‘disgust sensitivity’). Our study explored the neural expression of this trait, and demonstrates that individual variation in disgust sensitivity is significantly correlated with participants' ventroanterior insular response to viewing pictures of disgusting, but not appetizing or bland, foods. Similar correlations were also seen in the pallidum and orofacial regions of motor and somatosensory cortices. Our results also accord with comparative research showing an anterior to posterior gradient in the rat pallidum reflecting increased ‘liking’ of foods [Smith, K. S. and Berridge, K. C. (2005) J. Neurosci., 25, 849–8637].