Eyeblink conditioning leads to fewer synapses in the rabbit cerebellar cortex

Eyeblink conditioning involves the pairing of a conditioned stimulus (tone) to an aversive unconditioned stimulus (air puff). Although the circuitry that underlies this form of learning is well defined, synaptic changes in these structures have not been fully investigated. This experiment examined synaptic structural plasticity in the cerebellar cortex, a structure that has been found to modulate the acquisition and timing of the conditioned response. Long-term depression of Purkinje cells (PCs) in the cerebellar cortex has been proposed as a mechanism for releasing inhibition of the interpositus nuclei, a structure critical for the formation of the CR. Adult albino rabbits were randomly allocated to either a paired, unpaired, or exposure-only condition. The results showed a significant decrease in the number of excitatory synapses in the outer layer of the cerebellar cortex in the conditioned rabbits compared with controls. This finding suggests that a reduction in the number of excitatory synapses may contribute to the lasting depression of PC activity that is associated with eyeblink conditioning.

Analysis of age, stature, body mass, BMI and quality of elite soccer players from 4 European Leagues

AIM

The aim was to identify which league (English Premier League, Spanish La Liga Division, Italian Serie A and German Bundesliga) contained the highest quality players and whether differences in age, stature, body mass and BMI existed between the different positions in different leagues.

METHODS

Data were collected concerning 2,085 professional soccer players playing in these 4 leagues during the 2001-2002 season. Player quality was determined by the leagues' number of international players and their nations' FIFA World Ranking (FWR).

RESULTS

The La Liga Division contained the highest quality players (mean FWR) (11.5+/-13.8), followed by the Serie A (13.3+/-21.3), the Premier League (30.6+/-27.3) and the Bundesliga (30.7+/-27.1), respectively. Also, differences were found between the age, stature, body mass and BMI of players in different positions and in the different leagues. Age had a significant influence on position with goalkeepers (years) (27.4+/-5.3) being older than midfielders (26.2+/-4.3) and forwards (25.8+/-4.2) and defenders (26.8+/-4.3) being older than forwards. Players from the Bundesliga had the greatest stature (m) (1.83+/-0.06), body mass (kg) (77.5+/-6.4) and BMI (kg x m(-2)) (23.2+/-1.1) of the 4 leagues. In reflection, La Liga's players had the shortest stature (1.80+/-0.06) and the Serie A players had the least body mass (74.3+/-5.4) and BMI (22.8+/-1.1).

CONCLUSIONS

The differences discovered suggest either differences in playing style and physical demands of the different leagues, different physical conditioning methods or, alternatively, that there are desirable characteristics of players with teams in all 4 leagues seeking such players.

Environmental policy. Counting the cost of deforestation

To halt the dramatic alteration in our climate, there must be a reduction in the emission of greenhouse gases. As Bonnie and colleagues discuss in their Perspective, conservation of forests will increase carbon sequestration and decrease greenhouse gas emissions. In this issue, a cost-benefit analysis by Kremen et al. demonstrates the benefits of forest conservation on a local and global scale.

Global biodiversity scenarios for the year 2100

Scenarios of changes in biodiversity for the year 2100 can now be developed based on scenarios of changes in atmospheric carbon dioxide, climate, vegetation, and land use and the known sensitivity of biodiversity to these changes. This study identified a ranking of the importance of drivers of change, a ranking of the biomes with respect to expected changes, and the major sources of uncertainties. For terrestrial ecosystems, land-use change probably will have the largest effect, followed by climate change, nitrogen deposition, biotic exchange, and elevated carbon dioxide concentration. For freshwater ecosystems, biotic exchange is much more important. Mediterranean climate and grassland ecosystems likely will experience the greatest proportional change in biodiversity because of the substantial influence of all drivers of biodiversity change. Northern temperate ecosystems are estimated to experience the least biodiversity change because major land-use change has already occurred. Plausible changes in biodiversity in other biomes depend on interactions among the causes of biodiversity change. These interactions represent one of the largest uncertainties in projections of future biodiversity change.

Global biodiversity scenarios for the year 2100

Scenarios of changes in biodiversity for the year 2100 can now be developed based on scenarios of changes in atmospheric carbon dioxide, climate, vegetation, and land use and the known sensitivity of biodiversity to these changes. This study identified a ranking of the importance of drivers of change, a ranking of the biomes with respect to expected changes, and the major sources of uncertainties. For terrestrial ecosystems, land-use change probably will have the largest effect, followed by climate change, nitrogen deposition, biotic exchange, and elevated carbon dioxide concentration. For freshwater ecosystems, biotic exchange is much more important. Mediterranean climate and grassland ecosystems likely will experience the greatest proportional change in biodiversity because of the substantial influence of all drivers of biodiversity change. Northern temperate ecosystems are estimated to experience the least biodiversity change because major land-use change has already occurred. Plausible changes in biodiversity in other biomes depend on interactions among the causes of biodiversity change. These interactions represent one of the largest uncertainties in projections of future biodiversity change.

Neonatal lupus syndrome: a case with chondrodysplasia punctata and other unusual manifestations

We report a case of a newborn infant whose mother had systemic lupus erythematosus (SLE) diagnosed before pregnancy. The child had clinical manifestations of neonatal lupus as well as chondrodysplasia punctata and other findings that resemble the congenital anomalies associated with the use of oral anticoagulants, with no history of exposure. We speculate that the combined action of the different maternal autoantibodies may produce the whole spectrum of manifestations.

Stability of human proportions through adolescent growth

Male and female subjects (n = 125) were measured on a battery of anthropometric tests every six months for a period of five years. Using maturity status as the temporal component (pubescent assessment stages one through five), proportionality characteristics of subjects were monitored as they matured toward the adult form. Subjects were assigned to one of the Hi, Mid and Lo sub-groups based on their score at PA stage one for each of 15 proportionality characteristics. Subsequently, those in the Mid group were removed from the analysis, while male and female subjects were pooled for the final ANOVA model. The results showed that a number of variables remained stable from PA stages one through five. That is, differences between the Hi and Lo groups were maintained throughout maturation. Predominantly, these included the proportional body segment breadth measures. Proportionality characteristics of the upper limbs appeared to stabilise from mid-adolescence. However, those related to the lower limb were not stable. In other words, a significant difference for the lower limb variables at PA stage one was not maintained through stages four and five. The results raised some doubts as to the suitability of using lower limb proportions as selection criteria in talent identification programs.

[Diagnosis of neonatal femoral thrombosis following umbilical arterial catheterization by ultrasonic flow detection]

At her second day of life, a 2,200 g, 34 weeks gestational age female newborn infant with idiopathic respiratory distress syndrome, under treatment with mechanical ventilation and monitored through an umbilical arterial catheter (UAC), had severe clinical signs of arterial obstruction of her left limb. Signs of occlusion at the common femoral artery level were evident at Doppler ultrasonography. Doppler determinations showed early arterial blood flow improvement before amelioration of skin coloration and arterial pulses, that allowed close observation and withholding of surgical treatment which was finally not necessary. Eighteen newborn babies with an umbilical arterial catheter were then prospectively followed by Doppler ultrasound flow determinations. No further cases with clinical signs of arterial occlusion were found and Doppler studies performed in these late cases showed normal results in all of them. Doppler ultrasound flow determination is helpful for the diagnosis and management of lower limb arterial obstruction in newborn infants with umbilical arterial catheters.

[Early onset neonatal septicemia caused by Listeria monocytogenes]

Listeria monocytogenes can cause sepsis and meningitis during the neonatal period. Six cases of early onset neonatal sepsis caused by Listeria monocytogenes are reported here. These cases were diagnosed in a private hospital at Santiago, Chile from December 1984 throughout November 1986. The incidence rate was 1.4 x 1,000 liveborns. Clinical findings included prematurity (6), meconium stained amniotic fluid (6), hepatomegaly (6), splenomegaly (6), maculopapular exanthem (4), anal prolapse (3) and meningitis (1). Additionally 5 patients developed respiratory distress and 4 required ventilatory support. Overall mortality was 50% (3/6). All deaths were related to respiratory failure and occurred during the first week of disease. All patients received ampicillin and amikacin early in the course of their infection. Listeriosis of the newborn infant might be preventable by prompt recognition and treatment of maternal infections. Since Listeria infection in pregnancy is usually mild and symptoms and signs are nonspecific, prevention may be difficult. Pregnant women with fever of no clear origin or with an influenza like syndrome should be screened for listeriosis with cultures from blood, vagina and cervix samples.

Physical linkage of a GABAA receptor subunit gene to the DXS374 locus in human Xq28

We report the physical linkage of the gene encoding one of the subunits of the GABAA receptor (GABRA3) to the polymorphic locus DXS374 on the human X chromosome at Xq28. X-linked manic depression and other psychiatric disorders have been mapped to this region, and thus GABRA3 is a potential candidate gene for these disorders. DXS374--and therefore GABRA3--lies distal to the fragile X locus at a recombination fraction of approximately .15.

[Mortality by birth weight and survival by gestational age and route of delivery in premature infants]

Specific mortality rates for birthweight (BW) and survival for gestational age were determined in babies under 1500 g and less than 34 weeks gestational age (GA), which were born in a private hospital at Santiago, Chile, between 1983 and 1988. Mortality rates were 875/1,000 in babies under 750 g, 391/1,000 for BW between 750 and 999 g, 185/1,000 for BW 1,000 to 1,249 g, and 125/1,000 in newborns who weighed 1,250 to 1,499 g. Survival increased with gestational age from 39% under 26 weeks to 57% at 26 and 27 weeks, reaching 83% at 28 and 29 weeks, 90% at 30 and 31 and 87% at 32 and 33 weeks. No significant difference was found neither in mortality nor in intracranial hemorrhage (ICH) incidence between newborns delivered by cesarean section or vaginal way. Survival of babies born after 26 weeks GA and weighing over 750 g was comparable with that reported by others. The type of delivery is not likely to play a role by itself in mortality or in incidence of severe ICH.

Therapeutic potential of fish oil in the treatment of ulcerative colitis

In a pilot study six patients with active ulcerative colitis and six healthy controls were given fish oil (MaxEPA) containing 3-4 g of eicosapentaenoic acid daily for a period of 12 weeks. There was a significant improvement in the patients' symptoms and histological appearance of the rectal mucosa by the end of the treatment period. There was significant fall in neutrophil chemiluminescence during treatment in patients, whereas no change was observed in the control group. Neutrophil leukotriene B4 levels fell significantly during treatment. Serum from patients receiving fish oil was significantly less chemotactic for neutrophils compared with control serum. Eicosapentaenoic acid inhibited neutrophil chemotaxis and chemiluminescence in vitro. The omega-3 fatty acids, which occur naturally in fish oils, may exert a beneficial effect by decreasing the production of inflammatory mediators.

Genetic and physical mapping of a novel region close to the fragile X site on the human X chromosome

We report the isolation and characterization of a novel DNA marker (1A1) in Xqter in the region of the fragile X. Genetic studies in families segregating for the fragile X syndrome suggest that 1A1 lies between the disease mutation and the distal locus, DXS52. Studies in normal and fragile X families show that 1A1 is tightly linked to DXS52 (Zmax = 17.20; theta max = 0.03) and F8 (Zmax = 7.01; theta max = 0.08). Multipoint mapping of families supports the order Xcen-DXS105-FRAXA-1A1-DXS52-(F8, DXS115)-Xqter. Pulsed-field gel electrophoresis (PFGE) studies demonstrate that 1A1 defines a new region of at least 2 Mb of DNA not physically linked to DXS52 or F8, thus extending the physical map of Xq27-qter to over 4 Mb. Complex partial digestion PFGE patterns, probably due to differing degrees of methylation, are observed with 1A1 in unrelated normal and fragile-X-positive individuals, whereas other distal markers give uniform digestion profiles. Physical data suggest that 1A1 lies in a region less CpG rich than other distal markers in Xq27-qter.

An intronic region within the human factor VIII gene is duplicated within Xq28 and is homologous to the polymorphic locus DXS115 (767)

The genomic sequences recognized by the anonymous probe 767 (DXS115) are localized to two sites within Xq28. One site lies within intron 22 of the factor VIII gene (FBC). Physical mapping suggests that the second site lies within 1.2 megabases of the F8C gene. The RFLPs detected by 767 are located within the second site. Genetic data suggest that F8C and DXS115 are tightly linked (theta max = .04; Zmax = 8.30). Recombination events in meioses informative for DXS52 (St14), DXS115, and F8C suggest that DXS115 and F8C lie distal to DXS52.

[Height, weight and head circumference according to gestational age in newborn infants born before 35 weeks]

A retrospective and collaborative study was done in Santiago, Chile, in order to obtain national data on birth-weight, height and head circumference of babies born at 24 to 34 weeks of gestation: 370 babies with reliable gestational age, single pregnancies and no maternal nor fetal morbidity were included in the study. Babies were born in three government and one private hospitals from 1982 to 1987. Mean birthweight, height and head circumference for each gestational age from 24 to 34 weeks are presented in tables with their S.D. and charts +/- 1.5 S.D. The national use of these tables and curves is recommended.

Inertial characteristics of adolescent male body segments

In response to the presently limited information on body segment inertial characteristics of children and adolescents this investigation estimated the mass, centre of mass and principal moments of inertia of adolescent male body segments. Significant prediction equations based on anthropometric measurements were then sought. Thirteen subjects were measured at 6-monthly intervals for 2.5 yr to provide inertial characteristics for the leg, thigh, lower trunk and upper trunk segments. These characteristics were derived using an elliptical zone modelling technique. Following a correlation analysis, significant prediction equations of segment inertial parameters were derived from five, or fewer, anthropometric measurements. For all cases, more than 84% of the variance in the dependent variable was accounted for with a maximum R2 value of 94% being recorded for the prediction of thigh segment mass. The use of these prediction equations offered accurate and convenient estimates of body segment inertial characteristics within the limitations applicable to all modelling approaches. In contrast to recent studies, these equations accommodated the current morphological status of the subject.

The anatomical and physiological characteristics of pre-adolescent males and females

Two hundred and two pre-adolescent subjects aged 7-12 years were examined on a battery of anatomical and physiological tests. The total sample comprised non-competitive children, and those involved in training for swimming or tennis. A series of analyses of variance were applied to the data to determine whether any differences existed between preadolescent males and females. No significant interaction between age, sex and sporting involvement was found which indicated sex differences to be independent of age and training group. The results revealed that males were superior to females in physical exercise capacity, PWC170, forced vital capacity, and hand grip strength. Males also demonstrated a lesser proportion of body fat than females but were more mesomorphic. No significant differences existed in any of the other tests.

Biological characteristics of young swimmers, tennis players and non-competitors

One hundred and twelve finalists in the State Swimming Championships aged between seven and twelve years and 65 ranked tennis players of similar age were selected on the basis of their sporting performances. A third group comprised children of similar socio-economic status who only took part in casual sport. The tests which were used in the study were those considered to be important for successful athletic performance. A multifactorial analysis of variance and post-hoc t-tests were applied to the data to determine if any statistical differences were apparent between the three groups. The results demonstrated that no size, body shape, flexibility, strength or lung function differences were evident between the competitors and non-competitors, but that the swimmers and tennis players were superior to the non-competitors in cardiovascular endurance.