bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Oral Application of Mycophenolic Acid on the Clinical Health Status of Sheep
Authors: Mohr A. I. , Lorenz I. , Baum B. , Hewicker‐Trautwein M. , Pfaffl M. , Džidić A. , Meyer H. H. D. , Bauer J. , Meyer K.
Published: February 2007

Mycophenolic acid (MPA) is an immunosuppressive metabolite of various fungi, especially of Penicillium roqueforti, and can be found in considerable amounts in mouldy silage. The aim of this study was to investigate the effect of MPA on sheep. Thirty‐six castrated male sheep aged 7 ± 1 months were randomly divided into four groups of nine sheep. Different dosages of MPA were administered orally to all groups (group 1/2/3/4: 0/10/70/300 mg MPA/animal daily) for a period of 44 days. Throughout the trial, the sheep were examined daily. Jugular vein blood was taken twice weekly to analyse haematological and biochemical parameters. No significant influence was observed on the number of erythrocytes, thrombocytes, leucocytes (including differentiation), packed cell volume, haemoglobin‐, glucose‐ and bilirubin‐concentration, activity of alanine amino transferase, aspartate amino transferase and glutamate dehydrogenase. Even an oral application of up to 300 mg MPA/animal daily, which is equivalent to 5.4 mg/kg body weight, did not affect the sheep's general state of health and weight gain significantly. Mycophenolic acid and its glucuronide were analysed in plasma samples of groups treatments from day 1 on with mean concentrations up to 0.29 ± 0.13 μg/ml (MPA) and 11.0 ± 2.9 μg/ml (MPA glucuronide) respectively (group 4). There were no indications for a ruminal reduction of MPA. The postmortem dissection revealed minor alterations in lung, spleen, liver and kidneys, unrelated to the MPA dosage. The results of the study indicate that MPA concentrations occurring naturally in silage have no obvious impact on sheep health.
Physiological and behavioral responses of Bathynerita naticoidea (Gastropoda: Neritidae) and Methanoaricia dendrobranchiata (Polychaeta: Orbiniidae) to hypersaline conditions at a brine pool cold seep
Authors: Van Gaest Ahna L. , Young Craig M. , Young John J. , Helms Alicia R. , Arellano Shawn M.
Published: February 2007

Bathynerita naticoidea (Gastropoda: Neritidae) and Methanoaricia dendrobranchiata (Polychaeta: Orbiniidae) are two of the most abundant invertebrates associated with cold‐seep mussel beds in the Gulf of Mexico. At the methane seep known as Brine Pool NR‐1 (27 °43.415 N, 91 °16.756 W; 650 m depth), which is surrounded by a broad band of mussels (Bathymodiolus childressi), these species have distinctly different patterns of abundance, with the gastropod being found mostly at the outer edge of the mussel bed (average density in November 2003: 817 individuals·m−2 in outer zone, 20·m−2 in inner zone) and the polychaete being found almost exclusively near the inner edge (average density in November 2003: 3155 individuals·m−2 in inner zone, 0·m−2 in outer zone), adjacent to the brine pool itself. The salinity of the brine pool exceeds 120, so we hypothesized that M. dendrobranchiata should be more tolerant of high salinities than B. naticoidea. The opposite proved to be true. The gastropods were capable of withstanding salinities at least as high as 85, whereas the polychaetes died at salinities higher than 75. Both species were osmoconformers over the range of salinities (35–75) tested. Behavioral responses of B. naticoidea to salinities of 50, 60, and 70 were investigated in inverted vertical haloclines. Gastropods generally did not enter water of salinity greater than 60, but tolerated short periods at 60. Behavioral avoidance of brine should limit the vertical distribution of B. naticoidea in the inner zone to the top 2.5–5 cm of the mussel bed. Behavior is also a likely (though unproven) mechanism for controlling horizontal distribution of this species across the mussel bed. Methanoaricia dendrobranchiata can tolerate short excursions into the brine, but probably avoids hypersaline conditions by aggregating on the tops of the mussels.
Three‐year investigations into sperm whale‐fall ecosystems in Japan
Authors: Fujiwara Yoshihiro , Kawato Masaru , Yamamoto Tomoko , Yamanaka Toshiro , Sato‐Okoshi Waka , Noda Chikayo , Tsuchida Shinji , Komai Tomoyuki , Cubelio Sherine Sonia , Sasaki Takenori , Jacobsen Karen , Kubokawa Kaoru , Fujikura Katsunori , Maruyama Tadashi , Furushima Yasuo , Okoshi Kenji , Miyake Hiroshi , Miyazaki Masayuki , Nogi Yuichi , Yatabe Akiko , Okutani Takashi
Published: February 2007

We report the first study of sperm whale‐fall ecosystems, based on mass sinking of whale carcasses at shelf depths in the northwest Pacific. We conducted three observations over a 2‐year period on replicate sperm‐whale carcasses implanted at depths of 219–254 m off the southern part of Japan from July 2003 to August 2005. The study was made possible by a mass stranding of sperm whales in January 2002, and the subsequent sinking of 12 carcasses in the waters off Cape Nomamisaki. Dense aggregations of unique chemosynthesis‐based fauna had formed around the whale carcasses after 18 months (July 2003). The mytilid mussel Adipicola pacifica was the most abundant macrofaunal species and covered most of the exposed bone surfaces. The general composition of the fauna was similar to that of deep‐water reducing habitats, but none of the species appearing in this study has been found at hydrothermal vents, cold seeps or deep‐water whale falls. A new species of lancelet, which was the first record of the subphylum Cephalochordata from reducing environments, a new species of Osedax; a rarely encountered benthic ctenophore, and a rare gastropod species were discovered at this sperm whale‐fall site. Benthic communities were similar across all the carcasses studied, although the body sizes of the whales were very different. The succession of epifaunal communities was relatively rapid and the sulphophilic stage was considerably shorter than that of other known whale falls.
Diallel analysis of root‐knot nematode resistance based on galling index in upland cotton
Authors: Zhang J. F. , Waddell C. , Sengupta‐Gopalan C. , Potenza C. , Cantrell R. G.
Published: February 2007

The southern root‐knot nematode (RKN) [Meloidogyne incognita (Kofoid and White) Chitwood) RKN] is one of the most destructive pests in the Cotton Belt of the U.S. Developing and employing resistant cultivars is the most economical and efficient method for RKN management. This greenhouse investigation was conducted to understand the quantitative genetic basis of RKN resistance in the major RKN resistance sources using a nine‐parent diallel analysis based on improved RKN evaluation techniques. The selected genotypes consisted of three ‘Aubrun 623 RNR’ (here RNR = Root‐knot Nematode Resistance)‐derived resistant lines, one moderately resistant cultivar ‘Acala Nem‐X’, and five susceptible cultivars. Comparison between F1 and their parents in galling index revealed that the RKN resistance is partially dominant. The general combining ability was more important than the specific combining ability for RKN resistance. The estimates for broad‐sense and narrow‐sense heritabilities on galling index were 0.82 and 0.65, respectively, indicating that RKN resistance in the Auburn and Nem‐X resistance sources is largely controlled by genetic and additive effects. The minimum number of genes for RKN resistance was estimated to be two. Therefore, under reliable and uniform RKN inoculation and infestation conditions, single plant selection should be efficient in transferring Auburn RKN resistance into elite genetic backgrounds.
Heterosis in yield, endotoxin expression and some physiological parameters in Bt transgenic cotton
Authors: Dong H. Z. , Li W. J. , Tang W. , Li Z. H. , Zhang D. M.
Published: February 2007

Although heterosis in cotton has been studied for many decades, very little is known about the performance of hybrids derived from Bt transgenic cotton parents. In order to known better the heterosis performance, yield and endotoxin expression in 20 hybrids (F1) and their Bt transgenic parents were examined from 2002 to 2003 (Experiment 1), and the dynamics of source, sink and their ratios in a well‐performing hybrid H01 were investigated in 2004 and 2005 (Experiment 2). Results in Experiment 1 showed an average mid‐parent heterosis of 21.3% and an over check heterosis of 7.6% in lint yield. Considerable heterosis was also detected in boll numbers, boll size and Bt protein content. Of the 20 hybrids, H01 (K0215 × K643) exhibited the greatest heterosis in yield and Bt protein content in 2002 and 2003, while lint yields of H01 were increased 12.6% and 9.1% in 2004, and 11.7% and 8.9% in 2005, compared with K0215 and K643 in Experiment 2, respectively. Significant heterosis for dry matter accumulation and dry matter allocation to reproductive organs and ratio of fruiting forms/total plant (w/w) were also detected in H01. Sources (leaf area, leaf area index, leaf dry weight per plant and diurnal performance of photosynthesis), sinks (number of fruiting nodes, fruiting forms and dry weight of fruiting forms per plant) and the flow from source to sink were significantly enhanced in H01 relative to its parents. Both total N and Bt protein in H01 were higher than those in its parents. Significant correlation was also found between total N and Bt protein in the main‐stem leaves (R2 = 0.877**). It is concluded that there existed considerable heterosis in yield, yield components and endotoxin expression in some Bt transgenic hybrids. Yield advantage of hybrid cotton (F1) over parents can be attributed to improved source, sink and flow, while the enforced expression of Bt genes in hybrid cotton appeared to be due to the enhanced nitrogen level in plants.
Cytogenetics of a new trispecies hybrid in cotton: [(Gossypium hirsutum L. × G. thurberi Tod.)2 × G. longicalyx Hutch. & Lee]
Authors: Konan O. N. , D'Hont A. , Baudoin J.‐P. , Mergeai G.
Published: February 2007

A three‐species hybrid named HTL including Gossypium hirsutum L. [2n = 4 x = 52, (AD)1 genome] was created using the pseudophyletic introgression method with G. longicalyx Hutch. & Lee (2n = 2x = 26, F1 genome) as donor parent and G. thurberi Tod. (2n = 2x = 26, D1 genome) as bridge species. The new hybrid was totally self‐sterile and its interspecific status was confirmed using simple sequence repeat markers and cytogenetic analysis. Cytogenetic studies showed that its chromosome configuration was 2n = 52 = 14.13 I + 15.10 II + 1.03 III + 0.9 IV + 0.03 V + 0.13 VI (where I, II, III, IV, V and VI are univalents, bivalents, trivalents, tetravalents, pentavalents and hexavalents, respectively). Prospects for successfully exploiting the HTL hybrid in breeding programmes are discussed.
Personal supervision for paediatricians
Authors: O’Keeffe Mick J , Shelton Doug C
Published: February 2007

Abstract:  Contemporary paediatric practice includes considerable exposure to complex, chronic problems with prominent elements of social and emotional disruption. The psychological burden placed on paediatricians involved in this type of work is poorly recognised, both during training and beyond. Personal supervision for paediatricians is put forward as a potentially useful process to assist in maintenance of professional standards and personal well‐being.
Short‐term outcomes of infants of substance‐using mothers admitted to neonatal intensive care units in New South Wales and the Australian Capital Territory
Authors: Abdel‐Latif Mohamed E , Bajuk Barbara , Lui Kei , Oei Julee ,   the NSW on ACT Neonatal Intensive Care Units’ Study (NICUS) Group
Published: February 2007

Aim:  Illicit substance use during pregnancy is associated with an increased rate of perinatal complications. Our study examines if outcome of infants of substance‐using mothers (ISMs) in the neonatal intensive care unit (NICU) setting is similar to unexposed infants (controls).

Methods:  A prospective state‐wide NICU study comparing ISMs to control infants admitted to 10 NICUs during a 3‐years period (2001–2003). An ISM was defined as an infant whose mother admitted to or was documented to have used substances of dependency (illicit or otherwise) during this pregnancy.

Results:  There was a preponderance towards prematurity with ISMs comprising 5.1% (n = 310) of 6120 high risk infants (6.2% (n = 165) <32 weeks gestation and 6.8% (n = 39) of 22–26 weeks gestation). More ISMs were outborn and had significantly lower mortality rate, particularly in the <32 week gestation subgroup (adjusted OR 0.517 95% CI 0.277–0.962, P < 0.037). ISMs also demonstrated a non‐significant trend towards an increased risk of neonatal morbidities. The pattern of rural and urban substance use was different, with a higher incidence of opiate use (49.3% vs. 26.9%, P < 0.001) in urban areas. Most opiate using mothers (85.6%), irrespective of rural or urban residence, were enrolled in methadone programmes. ISMs had a higher incidence of antepartum haemorrhage and chorioamnionitis and fewer were given antenatal steroids.

Conclusion:  ISMs are common in the high‐risk NICU population. Further studies are needed to confirm the lower mortality rate and long‐term outcomes in these infants.
Population‐based study of paediatric head injury
Authors: Mitra Biswadev , Cameron Peter , Butt Warwick
Published: February 2007

Aim:  There is a paucity of population‐based studies regarding the spectrum of paediatric head injury from mild through serious to fatal paediatric head injury. The aims of the present study were to determine the incidence, demographics and outcome of significant head injury in a state‐wide population of children aged 0–15 years. A secondary aim was to determine if any serious head injuries were being missed under the current management protocols of the state‐wide trauma system.

Methods:  A retrospective review of significant head injury in all paediatric patients over a period of 2 years was undertaken. Data were collected from the Victorian State Trauma Outcome Registry and Monitoring database, the Victorian Emergency Minimum Dataset and from the Victorian Institute of Forensic Medicine.

Results:  The incidence of paediatric head injury in Victoria over the 2‐year period was 765 per 100 000 per year. The incidence of admitted head injuries was 75 per 100 000 per year and the incidence of significant head injury was seven per 100 000 or 151 children. Forty‐one per cent of these injuries required surgical intervention. Mortality was 1.6 children per 100 000. All patients who died presented with a Glasgow Coma Score (GCS) of 3 and had multiple other risk factors. There were no deaths in patients discharged from hospital. Demographic and clinical factors associated with higher mortality and morbidity was determined.

Conclusion:  The incidence of significant paediatric head injury was low. Deaths occurred early and were always associated with significant early clinical features of severe head injury. This highlights the importance of strategies for the prevention of head injuries. There appeared to be no serious head injuries missed during the study period.
Trends in use and outcome of newborn infants treated with high frequency ventilation in Australia and New Zealand, 1996–2003
Authors: Tingay David G , Mills John F , Morley Colin J , Pellicano Anastasia , Dargaville Peter A ,   Australian and New Zealand Neonatal Network
Published: February 2007

Aim:  To examine the use of high frequency ventilation (HFV) to treat newborn infants in Australia and New Zealand and the associated complications and outcomes.

Methods:  Data for all infants receiving HFV were collected from the 28 neonatal intensive care units contributing to the Australian and New Zealand Neonatal Network database between 1996 and 2003, inclusive. For comparison, the same data were gathered on all infants who received conventional mechanical ventilation (CMV) and nasal continuous positive airway pressure.

Results:  HFV was used to treat 3270 infants (10.1% of all ventilated infants) between 1996 and 2003; uptake doubled during this period from 5.9% to 12.6% of ventilated infants per year. HFV was most frequently applied in the context of extreme prematurity (29.9% of ventilated infants <26 weeks gestation). HFV is being increasingly used to treat complex diseases such as meconium aspiration syndrome and congenital diaphragmatic hernia (12.2% and 10.6% in 1996 to 25.2% and 48.4% in 2003, respectively, χ2‐test for trend, P < 0.001). Infants receiving HFV spent longer on respiratory support than infants treated with CMV (median 21 days compared with 7 days, Mann–Whitney test P < 0.001) and required a higher initial FiO2 (median 0.8 compared to 0.5, Mann–Whitney test, P < 0.001). The use of HFV was associated with a higher mortality than CMV and nasal continuous positive airway pressure (39.7%, 10.1% and 0.4%, χ2‐test, P < 0.001). The incidence of death and intraventricular haemorrhage decreased over time in the HFV group (χ2‐test for trend, P < 0.001 and P = 0.02 respectively).

Conclusion:  HFV is an established mode of neonatal ventilation in Australia and New Zealand. HFV is being applied to infants at the greatest risk of serious adverse outcomes, most likely as a rescue therapy.
Nocturnal enuresis: Application of evidence‐based medicine in community practice
Authors: Cutting David A , Pallant Julie F , Cutting Felicity M
Published: February 2007

Aim:  To report the outcomes and follow‐up at 2 years of children with monosymptomatic nocturnal enuresis (MNE) managed in a private paediatric community practice utilising body‐worn alarms and supportive programmes.

Methods:  522 consecutive children presenting with MNE were assessed and managed with a comprehensive supportive programme and body‐worn alarm. Data were recorded prospectively and outcomes assessed at 6 and 24 months.

Results:  505 proceeded with management. A total of 79.0% achieved initial dryness within a median of 10 weeks. Of those achieving initial dryness 73.0% had remained dry at 6‐month follow‐up and 64% had remained dry at 24 months. A total of 99.2% follow‐up was achieved. Nineteen per cent of children required more than 16 weeks management with 56% achieving dryness. More girls achieved dryness than boys and in a shorter time. There was no gender difference in relapse rates at 6 and 24 months. No difference in achieving initial success was found with respect to initial severity of wetting, nor age. Relapse rates were unrelated to gender, age, or initial severity.

Conclusion:  MNE can be successfully managed using body‐worn alarms achieving good initial and long‐term complete dryness, without the need for expensive pharmacologic intervention. A strong supportive programme can make the management less arduous for child and family.
Determining causes of mortality in children enrolled in a vaccine field trial in a rural area in the Western Cape Province of South Africa
Authors: Moyo Sizulu , Hawkridge Tony , Mahomed Hassan , Workman Leslie , Minnies Deon , Geiter Lawrence J , Verver Suzanne , Kibel Maurice , Hussey Gregory D
Published: February 2007

Aim:  A mortality surveillance system was developed to identify and document causes of death among children enrolled in a tuberculosis vaccine field trial in South Africa. The aims of this study were to describe causes of mortality in children enrolled in a phase IV trial comparing intradermal with percutaneous administration of Bacille Calmette Guerin, and to compare causes of mortality recorded on death certificates with those obtained by clinical record review combined with verbal autopsies (CR/VA).

Methods:  For children who died, certified causes of death were compared with those determined by CR/VA.

Results:  Among 11 677 children enrolled, 177 deaths were notified over 4 years. The incidence rate of death was 6.8/1000 person‐years. Follow‐up time ranged from 0.03 to 35.3 months (median 4 months; interquartile range 1.4–8.5). The infant mortality rate was 12.5/1000 live births and the neonatal mortality was 3/1000 live births. Pneumonia, gastroenteritis and septicaemia were among top causes of mortality by both methods. ‘Sudden unexplained’ and ‘ill‐defined’ causes were among top causes of mortality based on CR/VA, while tuberculosis and ‘natural causes’ were among top causes based on death certificates. Important underlying causes of mortality by CR/VA include HIV/AIDS, prematurity/low birth weight and malnutrition. In 47% of deaths there was agreement on immediate causes of death. This increased to 54% when ‘natural causes’ and ‘sudden unexplained deaths’ were included.

Conclusion:  In this cohort mortality was largely due to infectious diseases. While CR/VA provided additional information on most deaths, this was not always sufficient to assign specific causes of death.
Blue blood
Authors: Robinson Paul D , Curtin Julie A , Van Asperen Peter
Published: February 2007

Abstract:  In a world of increasing immigration of a diverse range of nationalities, hereditary hemoglobin variants will be increasingly encountered, and should be considered in infants and children presenting with low saturations. We present a case report of an infant presenting with low oxygen saturations, who was extensively investigated before the correct diagnosis became apparent. Initial haemoglobin electrophoresis was normal, but subsequently abnormal on repeat testing. With further screening, a number of affected family members have since been identified.
Varicella encephalopathy in immunocompetent children
Authors: Carreño Amparo , López‐Herce Jesús , Verdú Alfonso , Riaza Mónica , García Elena
Published: February 2007

Abstract:  Two previously healthy girls presented acute encephalopathy due to varicella, with severe alteration of the conscious level and seizures. Both patients improved progressively after 15 days, with complete clinical recovery.
Molecular biological features of male germ cell differentiation
Authors: TANAKA HIROMITSU , HIROSE MIKA , TOKUHIRO KEIZO , TAINAKA HITOSHI , MIYAGAWA YASUSHI , TSUJIMURA AKIRA , OKUYAMA AKIHIKO , NISHIMUNE YOSHITAKE
Published: February 2007

Somatic cell differentiation is required throughout the life of a multicellular organism to maintain homeostasis. In contrast, germ cells have only one specific function; to preserve the species by conveying the parental genes to the next generation. Recent studies of the development and molecular biology of the male germ cell have identified many genes, or isoforms, that are specifically expressed in the male germ cell. In the present review, we consider the unique features of male germ cell differentiation. (Reprod Med Biol 2007; 6: 1–9)
Ovarian stimulation length, number of follicles higher than 17 mm and estradiol on the day of human chorionic gonadotropin administration are risk factors for multiple pregnancy in intrauterine insemination
Authors: GARRIDO NICOLÁS , MELO MARCO A.B. , SIMÓN CARLOS , REMOHÍ JOSÉ , PELLICER ANTONIO , MESEGUER MARCOS
Published: February 2007

Aim:  The aim of the present study was to identify the risk factors, their prognostic value on multiple pregnancies (MP) prediction and their thresholds in women undergoing controlled ovarian hyperstimulation (COH) with follicle stimulating hormone (FSH) and intrauterine insemination (IUI).

Methods:  A case‐control study was carried out by identifying in our database all the pregnancies reached by donor and conjugal IUI (DIUI and CIUI, respectively), and compared cycle features, patients’ characteristics and sperm analysis results between women achieving single pregnancy (SP) versus MP. The number of gestational sacs, follicular sizes and estradiol levels on the human chorionic gonadotropin (hCG) administration day, COH length and semen parameters were obtained from each cycle and compared. Student's t‐tests for mean comparisons, receiver–operator curve (ROC) analysis to determine the predictive value of each parameter on MP achievement and multiple regression analysis to determine single parameter influence were carried out.

Results:  Women with MP in IUI stimulated cycles reached the adequate size of the dominant follicle (17 mm) significantly earlier than those achieving SP. Also, the mean follicles number, and estradiol levels on the hCG day were higher in the CIUI and DIUI MP group. Nevertheless, only ROC curve analysis revealed good prognostic value for estradiol and follicles higher than 17 mm. Multiple regression analysis confirmed these results. No feature of the basic sperm analysis, either in the ejaculate or in the prepared sample, was different or predictive of MP. When using donor sperm, different thresholds of follicle number, stimulation length and estradiol in the prediction of MP were noted, in comparison with CIUI.

Conclusions:  MP in stimulated IUI cycles are closely associated to stimulation length, number of developed follicles higher than 17 mm on the day of hCG administration and estradiol levels. Also, estradiol has a good predictive value over MP in IUI stimulated cycles. The establishment of clinical thresholds will certainly help in the management of these couples to avoid undesired multiple pregnancies by canceling cycles or converting them into in vitro fertilization procedures. (Reprod Med Biol 2007; 6: 19–26)
Recombinant‐follicle stimulating hormone is more effective than urinary human menopausal gonadotropin in ovarian hyperstimulation for assisted reproductive technology treatment
Authors: NAKAGAWA KOJI , OHGI SHIREI , KOJIMA RIEKO , SUGAWARA KANA , HORIKAWA TAKASHI , ITO MEGUMU , IRAHARA MINOARU , SAITO HIDEKAZU
Published: February 2007

Aim:  The aim of the present study was to establish a standard protocol for ovarian stimulation with gonadotropin‐releasing hormone analog (GnRH‐a) long protocol using recombinant‐follicle stimulating hormone (rec‐FSH) preparations for assisted reproductive technology (ART) treatment.

Methods:  In 86 patients who underwent ovarian stimulation with GnRH‐a long protocol for ART treatment, 53 were stimulated by rec‐FSH preparations (rec‐FSH group) and the others were stimulated by urinary‐hMG (u‐hMG group) preparations. The subjects were randomly assigned to either of these preparations. Hormonal profiles, total doses of gonadotropins, duration of stimulation and ART results were compared in both groups.

Results:  The duration of stimulation was similar in both groups (9.2 ± 0.3 days and 9.2 ± 0.2 days, respectively). The total doses of gonadotropin in the rec‐FSH group (1505.3 ± 29.2 IU) was significantly lower than those in the u‐hMG group (2130.3 ± 54.6 IU, P < 0.0001). The FSH and LH values on the day of human chorionic gonadotropin (hCG) administration in the rec‐FSH group were significantly lower than those in the u‐hMG group. Pregnancy rates were 31.3% in the rec‐FSH group and 33.3% in the u‐hMG group, respectively.

Conclusions:  The present study showed that rec‐FSH preparations were more potent than conventional u‐hMG preparations and the protocol of the present study with rec‐FSH was a new ovarian stimulation protocol with GnRH‐a long protocol. (Reprod Med Biol 2007; 6: 27–32)
Stochastic description of complex and simple spike firing in cerebellar Purkinje cells
Authors: Shin Soon‐Lim , Rotter Stefan , Aertsen Ad , De Schutter Erik
Published: February 2007

Cerebellar Purkinje cells generate two distinct types of spikes, complex and simple spikes, both of which have conventionally been considered to be highly irregular, suggestive of certain types of stochastic processes as underlying mechanisms. Interestingly, however, the interspike interval structures of complex spikes have not been carefully studied so far. We showed in a previous study that simple spike trains are actually composed of regular patterns and single interspike intervals, a mixture that could not be explained by a simple rate‐modulated Poisson process. In the present study, we systematically investigated the interspike interval structures of separated complex and simple spike trains recorded in anaesthetized rats, and derived an appropriate stochastic model. We found that: (i) complex spike trains do not exhibit any serial correlations, so they can effectively be generated by a renewal process, (ii) the distribution of intervals between complex spikes exhibits two narrow bands, possibly caused by two oscillatory bands (0.5–1 and 4–8 Hz) in the input to Purkinje cells and (iii) the regularity of regular patterns and single interspike intervals in simple spike trains can be represented by gamma processes of orders, which themselves are drawn from gamma distributions, suggesting that multiple sources modulate the regularity of simple spike trains.
Priority of repetitive adaptation to mismatch response following undiscriminable auditory stimulation: a magnetoencephalographic study
Authors: Hoshiyama Minoru , Okamoto Hidehiko , Kakigi Ryusuke
Published: February 2007

We analysed two different neural mechanisms related to the unconscious processing of auditory stimulation, neural adaptation and mismatch negativity (MMN), using magnetoencephalography in healthy non‐musicians. Four kinds of conditioning stimulus (CS): white noise, a 675‐Hz pure tone, and complex tones with six (CT6) and seven components (CT7), were used for analysing neural adaptation. The seven spectral components of CT7 were spaced by 1/7 octaves between 500 and 906 Hz on the logarithmic scale. The CT6 components contained the same spectral components as CT7, except for the center frequency, 675 kHz. Subjects could not distinguish CT6 from CT7 in a discrimination test. A test stimulus (TS), a 675‐Hz tone, was presented after CS, and the effects of the presence of the same 675‐Hz frequency in the CS on the magnetoencephalographic response elicited by TS was evaluated. The P2m component following CT7 was significantly smaller in current strength than that following CT6. The equivalent current dipole for P2m was located approximately 10 mm anterior to the preceding N1m. This result indicated that neural adaptation was taking place in the anterior part of the auditory cortex, even if the sound difference was subthreshold. By contrast, the magnetic counterpart of the MMN was not recorded when CT6 and CT7 were used as standard and deviant stimuli, respectively, being consistent with the discrimination test. In conclusion, neural adaptation is considered to be more sensitive than our consciousness or the MMN, or is caused by an independent mechanism.
Methamphetamine‐induced structural plasticity in the dorsal striatum
Authors: Jedynak Jakub P. , Uslaner Jason M. , Esteban José A. , Robinson Terry E.
Published: February 2007

Repeated exposure to psychostimulant drugs produces long‐lasting changes in dendritic structure, presumably reflecting a reorganization in patterns of synaptic connectivity, in brain regions that mediate the psychomotor activating and incentive motivational effects of these drugs, including the nucleus accumbens and prefrontal cortex. However, repeated exposure to psychostimulant drugs also facilitates a transition in the control of some behaviors from action–outcome associations to behavior controlled by stimulus–response (S–R) habits. This latter effect is thought to be due to increasing engagement and control over behavior by the dorsolateral (but not dorsomedial) striatum. We hypothesized therefore that repeated exposure to methamphetamine would differentially alter the density of dendritic spines on medium spiny neurons (MSNs) in the dorsolateral vs. dorsomedial striatum. Rats were treated with repeated injections of methamphetamine, and 3 months later dendrites were visualized using Sindbis virus‐mediated green fluorescent protein (GFP) expression in vivo. We report that prior exposure to methamphetamine produced a significant increase in mushroom and thin spines on MSNs in the dorsolateral striatum, but a significant decrease in mushroom spines in the dorsomedial striatum. This may be due to changes in the glutamatergic innervation of these two subregions of the dorsal striatum. Thus, we speculate that exposure to psychostimulant drugs may facilitate the development of S–R habits because this reorganizes patterns of synaptic connectivity in the dorsal striatum in a way that increases control over behavior by the dorsolateral striatum.
Neuronal death in Drosophila triggered by GAL4 accumulation
Authors: Rezával Carolina , Werbajh Santiago , Ceriani María Fernanda
Published: February 2007

The GAL4/UAS system has been extensively employed in Drosophila to control gene expression in defined spatial patterns. More recently this system has been successfully applied to express genes involved in neurodegeneration to model various diseases in the fruit fly. We used transgenic lines expressing different levels of GAL4 in a particular subset of neurons involved in the control of rhythmic behaviour, so that its impact on neuronal physiology would result in altered locomotor activity, which could be readily assessed. We observed a striking correlation between gal4 dosage and behavioural defects associated with apoptotic neuronal loss in the specific GAL4‐expressing neurons. Increased gal4 dosage correlated with accumulation of insoluble GAL4, suggesting that the cascade of events leading to apoptosis might be triggered by protein deposits of either GAL4 or protein intermediates. Behavioural defects were rescued by expression of hsp70, a classic chaperone that also interferes with cell death pathways. In agreement with the latter, the viral caspase inhibitor p35 also rescued GAL4‐induced behavioural defects. Our observations demonstrate the intrinsic effects of GAL4 deregulation on neuronal viability and suggest that an excess of GAL4 might enhance neuronal deficits observed in models of neurodegeneration.
The midbrain raphe nuclei mediate primary reinforcement via GABAA receptors
Authors: Liu Zhong‐Hua , Ikemoto Satoshi
Published: February 2007

Because rats learn to lever‐press for brief electrical stimulation of the median and dorsal raphe nuclei (MRN and DRN, respectively), these brain sites have long been implicated in reward processes. However, it is not clear whether the MRN and DRN integrate reward‐related signals or merely contain fibers of passage involved in reward processes. To shed light on this issue, the present study employed chemicals that selectively modulate neurotransmission, in particular the GABAA receptor agonist muscimol. Rats quickly learned to lever‐press for muscimol infusions (50 and 100 µm) into the MRN or DRN. Muscimol was not self‐administered when cannulae were placed just outside these nuclei. The reinforcing effects of muscimol appeared to be greater when the drug was administered into the MRN than into the DRN, as demonstrated by higher infusion rates and better response discrimination. These observations are consistent with the additional finding that muscimol administration into the MRN, but not the DRN, induced conditioned place preference. The reinforcing effects of muscimol administration into the MRN were blocked by coadministration of the GABAA antagonist picrotoxin (100 µm) and by pretreatment with the dopamine receptor antagonist SCH 23390 (0.025 mg/kg, i.p.). The present results suggest that median and dorsal raphe neurons presumably inhibited by muscimol via GABAA receptors are involved in integration of primary reinforcement, and that median raphe neurons exert tonic inhibition over dopamine‐dependent reward circuitry. The midbrain raphe nuclei may be involved in a variety of reward‐related phenomena including drug addiction.
CB2 cannabinoid receptors promote mouse neural stem cell proliferation
Authors: Molina‐Holgado Francisco , Rubio‐Araiz Ana , García‐Ovejero Daniel , Williams Robert J. , Moore Jonathan D. , Arévalo‐Martín Ángel , Gómez‐Torres Oscar , Molina‐Holgado Eduardo
Published: February 2007

Neurospheres are clonal cellular aggregates of neural stem/precursor cells that grow in culture as free‐floating clusters. Activation of CB1 cannabinoid receptors, which are expressed by these cells, promotes proliferation. In the present study we investigated the expression of CB2 cannabinoid receptors and the effect of exogenous cannabinoids on neural stem/precursor cell proliferation. Neurospheres containing nestin‐positive and sn‐1 diacylglycerol lipase α‐positive cells expressed both CB1 and CB2 receptors, which were maintained through several passages. Application of the non‐selective cannabinoid agonist (HU‐210, 0.5 µm) stimulated bromodeoxyuridine incorporation and neurosphere formation. This action involved both CB1 and CB2 receptors as neurosphere formation was stimulated by either selective CB1 [arachidonyl‐2’chloroethylamide/(all Z)‐N‐(2‐cycloethyl)‐5,8,11,14‐eicosatetraenamide (ACEA), 200 nm and 1 µm] or CB2 (JWH‐056, 0.5 µm) agonists. In addition, CB1 or CB2 antagonists (1 µm SR‐141716A and SR‐144528, respectively) blocked basal proliferation, suggesting that endogenous cannabinoids are implicated in neurosphere proliferation. In addition, cannabinoid agonist‐stimulated proliferation was reduced by the Akt translocation inhibitor BML‐257 (12.5 µm), suggesting a role for phosphoinositide‐3 kinase signalling. Together, our results suggest that cannabinoids stimulate proliferation of neural stem/precursor cells acting on both CB1 and CB2 cannabinoid receptors through a phosphoinositide‐3 kinase/Akt pathway.
Hydrogen peroxide increases GABAergic mIPSC through presynaptic release of calcium from IP3 receptor‐sensitive stores in spinal cord substantia gelatinosa neurons
Authors: Takahashi Ayako , Mikami Maya , Yang Jay
Published: February 2007

GABAergic interneurons of the spinal cord substantia gelatinosa regulate the transmission of nociceptive information. Hydrogen peroxide (H2O2) is likely a diffusible messenger contributing to the development of long‐lasting pathological pain states after nerve injury. In this study, we examined the presynaptic effects of H2O2 on the inhibitory interneurons of mouse substantia gelatinosa (SG) using whole‐cell patch‐clamp recordings from spinal cord slices. H2O2 increased the frequency of GABAergic miniature inhibitory postsynaptic current (mIPSC) in a concentration‐dependent (10–1000 µm) manner. The profound increase in mIPSC frequency was diminished by thapsigargin or cyclopiazonic acid suggesting that the intracellular stored pool was the source of presynaptic calcium. Further examination revealed the 2‐aminoethoxydiphenil borate blockable inositol‐(1,4,5) trisphosphate receptor (IP3R) regulated pool of stored calcium as the likely source. The phospholipase C (PLC) blocker, 1‐(6‐[([17β]‐3‐methoxyestra‐1,3,5[10]‐trien‐17‐yl)‐amino]hexyl)‐1H‐pyrrole‐2,5‐dione (U73122), did not block the frequency increase, which suggested that the site of action of H2O2 lies downstream in the IP3 signalling pathway, and nifedipine‐sensitivity of the frequency increase indicated a possible role of calcium‐induced calcium‐release. However, a direct examination of L‐type voltage‐gated calcium channels (VGCC) demonstrated that H2O2 did not increase the calcium influx through these channels. The H2O2 effect on mIPSC frequency was markedly reduced in the opisthotonus (Opt) mutant mice with a known deletion in the IP3R1 gene. We demonstrated that H2O2 increased presynaptic activity in the GABAergic interneurons by the release of calcium from the IP3R‐regulated intracellular pool. The presynaptic IP3R could emerge as a novel target for preventing H2O2‐induced synaptic plasticity in substantia gelatinosa leading to pathological pain states.
Potassium currents in the hair cells of vestibular epithelium: position‐dependent expression of two types of A channels
Authors: Russo Giancarlo , Calzi Daniela , Martini Marta , Rossi Maria Lisa , Fesce Riccardo , Prigioni Ivo
Published: February 2007

The complement of voltage‐dependent K+ currents was investigated in hair cells of the frog crista ampullaris. The currents were recorded in transversal slices of the peripheral, intermediate and central regions of the crista by applying the patch clamp technique to cells located at different positions in the slices. Voltage‐clamp recordings confirmed that cells located in each region have a distinctive complement of K+ channels. Detailed investigation of the currents in each region revealed that the complement of K+ channels in intermediate and central regions showed no variations among cells, whereas peripheral hair cells differed in the expression of two classes of A‐type currents. These currents showed different kinetics of inactivation as well as steady‐state inactivation properties. We termed these currents fast IA and slow IA based on their inactivation speed. The magnitude of both currents exhibited a significant gradient along the transversal axis of the peripheral regions. Fast IA magnitude was maximal in cells located in the external zone of the crista slice and decreased gradually to become very small in the median zone (centre) of the section, while the gradient of slow IA magnitude was reversed. A‐type currents appear to act as a transient buffer that opposes hair cell depolarization induced by positive current injections. However, fast IA is partially active at the cell resting potential, while slow IA can be recruited only following large hyperpolarizations. Thus, two types of A currents are differentially distributed in vestibular hair cells and have different roles in shaping receptor potential.
Nitrogenase gene expression in the Chesapeake Bay Estuary
Authors: Short Steven M. , Zehr Jonathan P.
Published: February 2007

Like many estuaries, the Chesapeake Bay has pronounced gradients in salinity and nutrients. Previous studies have shown that there is a high diversity of nitrogenase (nifH) genes in the estuary, and that there are specific distributions of individual nifH phylotypes. In contrast to previous work that revealed the remarkable diversity of nifH phylotypes in the Chesapeake estuary, in this study of nifH expression we only detected two phylotypes, and both were phylogenetically related to cyanobacterial nifH genes. One of the phylotypes was closely related to a nifH sequence from the filamentous, heterocystous cyanobacterium Anabaena cylindrica, and was found at the head of the estuary. The other phylotype was found in a sample collected near the mouth of the estuary and was closely related to nifH sequences from Group A unicellular cyanobacteria, which has previously been reported in oceanic waters only. These nifH phylotypes had distinct patterns of expression that were restricted to different regions of the Chesapeake Bay. This study provides the first evidence of nifH expression in the Chesapeake Bay, and suggests that diazotrophic unicellular cyanobacteria have a broader distribution and activity than previously recognized.
Earthquake relief: Iranian nurses’ responses in Bam, 2003, and lessons learned
Authors: Nasrabadi A. N. , Naji H. , Mirzabeigi G. , Dadbakhs M.
Published: February 2007

Background:  Man‐made or natural disasters appear to be occurring more frequently around the world. It is important that nurses in all specialties should be prepared to care for people affected by disasters.

Aim:  To explore Iranian Registered Nurses’ experiences in disaster relief in the Bam earthquake, Iran in 2003.

Methods:  This study was qualitative with 13 participant nurses. Data were obtained through semi‐structured serial interviews and analysed using the latent content method.

Findings:  Three general themes emerged: (a) the need for previously prepared practical protocols, (b) the need for qualified and real teamworking in the situation, and (c) the need to establish periodic comprehensive training programmes in disaster relief nursing.

Conclusion:  It has become urgent for health agencies and related public services to collaborate, and for all health professionals to become knowledgeable about disaster preparedness. Crisis management, which has become more prevalent for many organizations, is an important strategic initiative for nursing, helping them provide the infrastructure to respond effectively to emergencies and unpredictable events. It is important in today’s world that hospital and nursing organizations develop a strategic system to handle disaster situations.
Narrative inquiry into life experiences of refugee women and men
Authors: Pavlish C.
Published: February 2007

Background:  Africa is the site of many refugee camps, and non‐governmental agencies are often responsible for providing programmes and services to improve refugees’ quality of life and health in temporary encampments. Rwanda hosts three refugee camps as a result of the 1994 genocide.

Aim:  This research examines meaningful life experiences as narrated by women and men Congolese refugees residing in a refugee camp in Rwanda.

Methods:  Two in‐depth interviews were conducted with 15 refugee men and 14 refugee women. Content in the research text was analysed separately by gender.

Findings:  Women’s experiences revealed themes of leaving the good life behind, worrying about their daughters, feeling ambivalent about marriage and lacking hope. Men’s experiences revealed themes of leaving the good life behind, having no peace in the heart and fearing the future.

Conclusions:  Listening to refugee voices in narrated life experiences provides an opportunity for non‐governmental organizations to create programmes and services that pertain closely to refugees’ life experiences.
Government chief nursing officers’ perceptions of barriers to using research on staffing
Authors: Baernholdt M. , Lang N. M.
Published: February 2007

Background:  Current global healthcare problems include nursing shortages contributing to low nurse staffing. Low nurse staffing is associated with poor patient and nurse outcomes, but research utilization using these findings especially at the policy level remains slow.

Research objective:  To assess high‐ranking government nurses’ perceptions of barriers to using research on nurse staffing.

Methods:  An electronic information message about the impact of nurse staffing was presented to government chief nursing officers (CNOs) from 110 countries. The CNOs’ perceptions of local barriers to utilizing these research findings were then assessed in an electronic survey. The four factors that influence the first two stages of Rogers’s five‐stage model of diffusion were examined. The factors, characteristics of the adopter, organization, innovation and communication, were measured using an adapted version of the BARRIERS scale.

Results:  Barriers were present in all four characteristics. The top barrier was lack of reports and studies in one place. Other barriers were lack of cooperation within the organization and lack of awareness of the research findings. Differences according to Gross National Income were also noted.

Conclusions:  The CNOs and other health policy advisors can use the findings in planning for adequate nurse staffing. Development of electronic newsletters with summaries of pertinent research for CNOs and other policy advisors is needed. Future studies on nurse staffing are warranted. They should focus on other settings and how best to share research findings with policymakers.
Psychosocial response in emergency situations – the nurse’s role
Authors: Hughes F. , Grigg M. , Fritsch K. , Calder S.
Published: February 2007

Background:  It is critical to ensure that nurses have the skills and knowledge to respond effectively and to contribute to the psychosocial recovery of survivors of emergencies, particularly as an increasing proportion of the population is at risk of being exposed to a catastrophe. Over a decade ago it was reported that 16% of the world’s population was at risk of experiencing some kind of catastrophic event. That has now risen with a total of 16% vulnerable to flood alone worldwide (Ministry of Health 2005). In the first semester of 2005, there were 174 natural disasters affecting 86 countries, resulting in the deaths of 5967 people, affecting a total of 60 million with an estimated damage of $6.3 billion (US$) (Centre for Research on the Epidemiology of Disasters 2005).

Aim:  To describe the nursing contribution to the psychosocial recovery of survivors of emergencies during the emergency preparedness and planning stage and in promoting recovery over the longer term.

Methods:  Data for this article was sourced from relevant literature including World Health Organization policy and guidelines regarding mental health in emergencies.

Implications for education, training and practice:  It is vital that nurses realize they are too vulnerable to the effects of an emergency situation and that steps can be taken to protect nurses from enduring psychosocial effects.