bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective recruitment: Evidence for task-dependent gating of inputs to the cerebellum
Authors: Shahshahani Ladan , King Maedbh , Nettekoven Caroline , Ivry Richard , Diedrichsen Jörn
Published: April 2024

fMRI studies have documented cerebellar activity across a wide array of tasks. However, the functional contribution of the cerebellum within these task domains remains unclear because cerebellar activity is often studied in isolation. This is problematic, as cerebellar fMRI activity may simply reflect the transmission of neocortical activity through fixed connections. Here we present a new approach that addresses this problem. Rather than focus on task-dependent activity changes in the cerebellum alone, we ask if neocortical inputs to the cerebellum are gated in a task-dependent manner. We hypothesize that input is upregulated when the cerebellum functionally contributes to a task. We first validated this approach using a finger movement task, where the integrity of the cerebellum has been shown to be essential for the coordination of rapid alternating movements but not for force generation. While both neocortical and cerebellar activity increased with increasing speed and force, the speed-related changes in the cerebellum were larger than predicted by an optimized cortico-cerebellar connectivity model. We then applied the same approach in a cognitive domain, assessing how the cerebellum supports working memory. Enhanced gating was associated with the encoding of items in working memory, but not with the manipulation or retrieval of the items. Focusing on task-dependent gating of neocortical inputs to the cerebellum offers a promising approach for using fMRI to understand the specific contributions of the cerebellum to cognitive function.
Optogenetic silencing hippocampal inputs to the retrosplenial cortex causes a prolonged disruption of spatial working memory
Authors: Pinto-Correia Bárbara , Caldeira-Bernardo Patricia , Remondes Miguel
Published: April 2024

Working memory allows us to keep information in memory for the time needed to perform a given task. Such fundamental cognitive ability relies on a neural circuit including the retrosplenial cortex (RSC), connected to several cortical areas, functionally and anatomically, namely primary visual areas, and higher cognitive areas such as the cingulate, midcingulate, and subicular cortices. RSC bears intimate anatomical and functional connections with the hippocampus, and has been implicated in integrating and translating spatial-temporal contextual information between ego- and allocentric reference frames, to compute predictions about goals in goal-directed behaviors. The relative contribution of the hippocampus and retrosplenial cortex in working memory-guided behaviors remains unclear due to the lack of studies reversibly interfering with synapses connecting the two regions during such behaviors. We here used eArch3.0, a hyperpolarizing proton pump, to silence hippocampal axon terminals in RSC while animals perform a standard delayed non-match to place task. We found that such manipulation impairs memory retrieval, significantly decreasing performance and hastening decision-making. Furthermore, we found that such impairment outlasts light-activation of the opsin, its effects being noticed up to 3 subsequent trials.
Optogenetic silencing hippocampal inputs to the retrosplenial cortex causes a prolonged disruption of working memory
Authors: Pinto-Correia Bárbara , Caldeira Patricia , Remondes Miguel
Published: April 2024

Working memory allows us to keep information in memory for the time needed to perform a given task. Such fundamental cognitive ability relies on a neural circuit including the retrosplenial cortex (RSC), connected to several cortical areas, functionally and anatomically, namely primary visual areas, and higher cognitive areas such as the cingulate, midcingulate, and subicular cortices. RSC bears intimate anatomical and functional connections with the hippocampus, and has been implicated in integrating and translating spatial-temporal contextual information between ego- and allocentric reference frames, to compute predictions about goals in goal-directed behaviors. The relative contribution of the hippocampus and retrosplenial cortex in working memory-guided behaviors remains unclear due to the lack of studies reversibly interfering with synapses connecting the two regions during such behaviors. We here used eArch3.0, a hyperpolarizing proton pump, to silence hippocampal axon terminals in RSC while animals perform a standard delayed non-match to place task. We found that such manipulation impairs memory retrieval, significantly decreasing performance and hastening decision-making. Furthermore, we found that such impairment outlasts light-activation of the opsin, its effects being noticed up to 3 subsequent trials.
Glycosylated Antibiotics: New Promising Bacterial Efflux Pumps Inhibitors
Authors: Kamaz Zahraa Ali , Umar Haruna Isiyaku , Doshi Parth , Suri Praveenya
Published: April 2024

Antimicrobial resistance is considered a major concern problem; bacteria have evolved mechanisms to overcome antibiotics’ action through evolutionary process. One main resistance mechanism that bacteria developed is the pumping of the antibiotics out of bacterial cells by transmembrane transporter proteins known as efflux pumps. To overcome bacterial resistance guided by efflux pumps, efflux pumps inhibitors (EPIs) are small molecules that obstruct efflux pumps binding sites and its structural assembly leading to disability in the efflux pumps normal function, new EPIs which under the current study are created by modifying the chemical structure of most common antibiotics including Ampicillin, Penicillin, Chloramphenicol, Ciprofloxacin and Tetracycline, such antibiotics are modified by adding N-acetyl glucose amine moiety to acceptor OH group of the respective antibiotic, the newly modified antibiotics are glycosylated EPIs. To test the effectiveness of the new EPIs in inhibiting AcrB-TolC and MexA-OprM efflux pumps functions, ADME properties for all of glycosylated antibiotics have been measured through applying Lipinski’s role of 5, docking and simulation studies have been included as well. Docked glycosylated tetracycline has given the highest binding energy in the active sites of both pumps, with -9.4 against AcrB and -8.8 against MexA. The simulation study has confirmed the binding of the glycosylated tetracycline in the active sites of both pumps, as well as its stability during the biological dynamicity of both pumps (opening and closing channels). The results validation requires a long simulation time about 50 ns or more which was un applicable due to cost limitation, however, the newly glycosylated antibiotics have promising results that might make it eligible as drug candidates to overcome bacterial resistance.
Improved survival time: What can survival cure models tell us about population‐based survival improvements in late‐stage colorectal, ovarian, and testicular cancer?
Authors: Huang Lan , Cronin Kathleen A , Johnson Karen A. , Mariotto Angela B. , Feuer Eric J.
Published: April 2008

BACKGROUND

The objective of the current study was to investigate the long‐term impact of treatment advances on the survival of patients with late‐stage ovarian, colorectal (American Joint Committee on Cancer stage III, men), and testicular cancers by estimating the increase in the percentage cured from their disease and the change in survival time of uncured patients.

METHODS

Cause‐specific survival data from 1973 to 2000 were obtained from the Surveillance, Epidemiology, and End Results Program. Survival cure models were fit and were used to estimate the gain in life expectancy (GLE) attributed to an increase in the fraction of cured patients and to prolonged survival among noncured patients.

RESULTS

Treatment improvement for ovarian cancer resulted in a total GLE of 2 years, and 80% of that GLE was because of an extension of survival time in uncured patients (from 0.9 years to 2.1 years) rather than an increased cure fraction (from 12% to 14%). In contrast, the cure rate rose from 29% to 47% for colorectal cancer, representing 82% of a 2.8‐year GLE, and from 23% to 81% for testicular cancer, representing 100% of a 24‐year GLE.

CONCLUSIONS

The current results suggested that treatment benefits for testicular and colorectal cancer in men with late‐stage disease primarily are the result of increases in cure fraction, whereas survival gains for ovarian cancer occur despite persisting disease. Cure models, in combination with population‐level data, provide insight into how treatment advances are changing survival and ultimately impacting mortality. Survival patterns reflect the underlying biology of response to cancer treatment and suggest promising directions for future research. Cancer 2008. Published 2008 by the American Cancer Society.
A practical interface for microfluidics and nanoelectrospray mass spectrometry
Authors: Freire Sergio L. S. , Yang Hao , Wheeler Aaron R.
Published: April 2008

We report a new method for fabricating nanospray ionization tips for MS, formed from glass substrates and the inert polymer, parylene‐C. Using a single photolithography step, the emitters are formed contiguously with microchannels, such that no dead volumes are observed. In addition, because the devices are very thin (∼0.3 mm) and the tips are formed at rectangular corners, the Taylor cone volumes are small, which makes the method attractive for future integration with microfluidic separations. Device performance was demonstrated by evaluating diverse analytes, ranging from synthetic polymers, to peptides, to nucleic acids. For all analytes, performance was similar to that of conventional emitters (pulled‐glass capillaries and the Agilent HPLC Chip™) with the advantage of rapid, batch fabrication of identical devices.
High incidence of distal vaginal atresia in mice lacking Tyro3 RTK subfamily
Authors: Wu Hui , Tang Hongmei , Chen Yongmei , Wang Haikun , Han Daishu
Published: April 2008

Vaginal atresia is a congenital abnormality of the female genitourinary system, and the specific molecular mechanism leading to failure of vaginal development remains to be elucidated. Here, we report that the female mice lacking Tyro3 RTK subfamily (Tyro3, Axl, and Mer) exhibit a high incidence of distal vaginal atresia. The ratios of the vaginal atresia in Tyro3 RTKs mutant female mice are as follows: 2.5% for Mer−/− mice, 4.0% for Axl−/−Mer−/−, 3.7% for Mer−/−Tyro3−/−, 16.06% for Tyro−/−Axl−/−Mer−/− mice. We did not find the vaginal atresia in Axl−/−, Tyro3−/−, Axl−/− Tyro−/−, and wild‐type mice. These observations suggest that Tyro3 RTKs play roles collaboratively in vaginal development, and Mer is more critical, Axl and Tyro3 support the function of Mer. The phenotype of mice with the vaginal atresia was characterized in this study. Tyro3 RTKs mutant mouse could be a useful model to study the mechanism of vaginal atresia formation. Mol. Reprod. Dev. 75: 1775–1782, 2008. © 2008 Wiley‐Liss, Inc.
Selective hydrogenation with copper catalysts: IV. Reaction of stearolate, oleate and conjugated esters with deuterium
Authors: Koritala Sambasivarao , Selke E.
Published: April 2008

β‐Eleostearate andtrans,trans‐conjugated diene were reduced with deuterium in the presence of copper chromite. Considerable exchange of hydrogen atoms of the starting material for deuterium atoms was observed. Conjugated double bond systems isomerized (positional and geometric) extensively during hydrogenation. Isomerization and exchange reactions occurred at a faster rate than hydrogen addition reaction. During early stages of the reaction, a large amount of the product formed contained no deuterium. Of the three possible mechanisms of hydrogen addition toβ‐eleostearate (1,2; 1,4 and 1,6), no one mechanism could account for all the products formed. Reduction oftrans‐9,trans‐11‐octadecadienoate at a higher temperature and pressure (200 C, 500 psi) caused a minimum of exchange and isomerization apparently due to sintering of the catalyst. Monoenes were formed fromtrans,trans‐conjugated diene by both 1,2 and 1,4 addition. Methyl oleate was not reduced, but extensive isomerization occurred. Deuterium was incorporated into isomeric monoenes. Mechanistic schemes are proposed to account for exchange, isomerization and hydrogen addition.
Liver cell transplantation for the treatment of inborn errors of metabolism
Authors: Meyburg J. , Hoffmann G. F.
Published: April 2008

Over the last 15 years, liver cell transplantation (LCT) has developed from an experimental laboratory technique to a potentially life‐saving therapeutic option. Because of its minimally invasive nature, the method is especially attractive for (small) children. In children with liver‐based inborn errors of metabolism, this transfer of enzyme activity can be regarded as a gene therapy, which can be installed independently and additionally to conservative treatment concepts. To date 14 children with inherited metabolic diseases have undergone LCT in various centres. Although individual results are encouraging, different treatment protocols, difficulties in the objective assessment of function of the transplant, and finally the lack of a controlled study make it difficult to judge the overall significance of LCTin the treatment of metabolic diseases and call forcollaborative clinical research.
Renewal-type limit theorem for the Gauss map and continued fractions
Authors: SINAI YAKOV G. , ULCIGRAI CORINNA
Published: April 2008

In this paper we prove a renewal-type limit theorem. Given $\alpha \in (0,1)\backslash \mathbb {Q}$ and R>0, let qnR be the first denominator of the convergents of α which exceeds R. The main result in the paper is that the ratio qnR/R has a limiting distribution as R tends to infinity. The existence of the limiting distribution uses mixing of a special flow over the natural extension of the Gauss map.
Algebraic polymorphisms
Authors: SCHMIDT KLAUS , VERSHIK ANATOLY
Published: April 2008

In this paper we consider a special class of polymorphisms with invariant measure, the algebraic polymorphisms of compact groups. A general polymorphism is—by definition—a many-valued map with invariant measure, and the conjugate operator of a polymorphism is a Markov operator (i.e. a positive operator on L2 of norm 1 which preserves the constants). In the algebraic case a polymorphism is a correspondence in the sense of algebraic geometry, but here we investigate it from a dynamical point of view. The most important examples are the algebraic polymorphisms of a torus, where we introduce a parametrization of the semigroup of toral polymorphisms in terms of rational matrices and describe the spectra of the corresponding Markov operators. A toral polymorphism is an automorphism of $\mathbb {T}^m$ if and only if the associated rational matrix lies in $\mathrm {GL}(m,\mathbb {Z})$. We characterize toral polymorphisms which are factors of toral automorphisms.
Signal transduction pathways that regulate muscle growth
Authors: Wackerhage Henning , Ratkevicius Aivaras
Published: April 2008

Progressive high-resistance exercise with 8–12 repetitions per set to near failure for beginners and 1–12 repetitions for athletes will increase muscle protein synthesis for up to 72 h; approx. 20 g of protein, especially when ingested directly after exercise, will promote high growth by elevating protein synthesis above breakdown. Muscle growth is regulated by signal transduction pathways that sense and compute local and systemic signals and regulate various cellular functions. The main signalling mechanisms are the phosphorylation of serine, threonine and tyrosine residues by kinases and their dephosphorylation by phosphatases. Muscle growth is stimulated by the mTOR (mammalian target of rapamycin) system, which senses (i) IGF-1 (insulin-like growth factor 1)/MGF (mechano-growth factor)/insulin and/or (ii) mechanical signals, (iii) amino acids and (iv) the energetic state of the muscle, and regulates protein synthesis accordingly. The action of the mTOR system is opposed by myostatin-Smad signalling which inhibits muscle growth via gene transcription.
Magnetic reconnection with pressure gradient effect in compressible electron magnetohydrodynamics
Authors: Cai Huishan , Li Ding
Published: April 2008

The general dispersion relation of the tearing mode with charge separation and pressure gradient effects in the whistler frequency is analytically derived in the framework of electron magnetohydrodynamics (EMHD). It is shown that pressure gradient effect enhances the growth rate, and makes the EMHD tearing mode drift. The growth rate of the EMHD tearing mode is significantly affected by the pressure gradient effect in the large pressure gradient limit. Furthermore, in this limit, the growth rate in the compressible EMHD fluid is much different from that in the incompressible EMHD fluid.
Growth performance, feed efficiency and carcass and meat quality of tropically adapted breed types from different farming systems in South Africa
Authors: Strydom P. E. , Frylinck L. , van der Westhuizen J. , Burrow H. M.
Published: April 2008

Two experiments measured the ability of tropically adapted beef breeds from resource-poor farmer herds in South Africa to produce high quality beef under commercial feedlot conditions. The resource-poor farming sector consists of ‘emerging’ and communal farmers. The herd and breed groups consisted of Sanga types (tropically adapted Bos taurus breed) including Nguni, Tuli, Bonsmara and Drakensberger, as well as Brahman and non-descript groups. The cattle were slaughtered after an average of 97 days in the first experiment and after an average of 92, 140 and 169 days on a grain-based diet in the second experiment. Growth performance, carcass quality and yield, occurrence of disease and meat quality were measured.
The performance of the breeds groups was a function of their genetic potential and herd type (carcass weight and condition at arrival). Steers from emerging and communal farmer herds enter the feedlot at a lighter weight, but show similar growth performance to achieve acceptable, albeit lighter carcass weights, than their commercial counterparts. The incidence of disease was no different between commercial, emerging and communal herds. Carcass and meat quality analyses indicate small or no differences between herd types or breeds, except that Brahman produced tougher meat. It was concluded that cattle from resource-poor farmer herds have the ability to meet the specifications of South Africa’s commercial beef markets, indicating a genuine opportunity for import substitution, whereby the more than 5 million cattle in resource-poor farmer herds could be used to overcome the significant shortfall in South Africa’s domestic beef market demand.
An evaluation of the Language and Thought software*
Authors: Ward R. , Lindley P. , Rostron A. , Sewell D. , Cubie R.
Published: April 2008

This paper describes an evaluation of software developed with the aim of enabling hearing‐impaired children to explore and experience the use and effects of language. The software allows interactive graphics to be discussed and controlled by means of a simple‘natural’ language interface, thereby allowing the user to hold a written conversation with the computer. It is argued that by making written language interactive in this way, prelingually deaf children should be able to use, in the written medium, language learning strategies similar to those normally used by hearing children in the spoken medium.
Conceptual change in science: A research programme*
Authors: Driver R. , Scanlon E.
Published: April 2008

Abstract Studies undertaken in the UK and elsewhere have shown that secondary school pupils have difficulties in understanding certain theories in the physical sciences and, moreover, that certain conceptual problems in these areas may even persist among science students in higher education.

The aims of this research project are to understand this process of conceptual change better, and to devise and test ways in which such a change can be promoted in classroom teaching programmes. Particular attention will be paid to the role that computer software tools can play in promoting such a change.

The effectiveness of these software tools will be investigated in small‐scale studies and in the context of classroom teaching. The findings will be made available to science teachers, teacher trainers and to those involved in educational software development.
Towards an educational Superlnterface
Authors: Diana I.P.F De , White T.N.
Published: April 2008

Abstract  It is presumed that recent technological innovations, combined with three more established (educational) technologies, could cause a drastic change in university education, if adequate organizational conditions could be created. Such conditions are needed to structure, channel and manage an as yet undreamed of flow of information. Closely related to the metaphor of the ‘Info Highway’, an educational ‘Superlnterface’ is described. Based upon networked computer platforms, such a human‐computer‐human interface is to support large scale telestudy (and teleworking). The Superlnterface is to be designed or is to evolve in such a way that reliable and valid organizational foundations for university education can be established. As the organizational foundation is so paramount, the authors would like to see serious research into the modelling of Superlnterface structures, resources, and dynamics. Indications of some such research issues are presented.
Modelling knowledge in Electronic Study Books
Authors: Hoede C.
Published: April 2008

Abstract  Knowledge graphs are a new form of knowledge representation. They are closely related to semantic networks and can be looked upon as in line with Schank's conceptual dependency theory and Sowa's conceptual graphs. The special feature of knowledge graphs is the use of a very restricted set of types of relations, that is considered to be the basic set of primitive relations. The theory of knowledge graphs is outlined in the first part of the paper. In the second part the possibilities of knowledge graphs for solving problems posed by Electronic (Study) Books will be discussed.
Interferon treatment of chronic hepatitis C with cirrhosis
Authors: Cooksley W. G. E.
Published: April 2008

Summary. Among patients with hepatitis C who have cirrhosis the rate of sustained response following interferon therapy is only half that of patients without cirrhosis. Although it has been suggested that a higher dose regime in patients with cirrhosis may improve response, this remains largely untested. The results of a recent Australian study of cirrhotic patients who were given an intense interferon programme of 4.5 MIU daily for 24 weeks were compared with previous studies of patients with hepatitis C. Of 11 studies of interferon response in chronic hepatitis C comparison of pretreatment variables showed considerable differences. Identification of predictors of response by univariate and multivariate analysis regularly indicated the importance of age and fibrosis. Analysis of six studies with either a poor (5% or less) or a reasonable (14–19%) sustained response rate to interferon in patients with cirrhosis suggested that a higher dose or longer duration of therapy was associated with better results. The experience of the Australian study, where 14% of patients had a sustained biochemical response to interferon and side‐effects were reasonably tolerated with careful monitoring, suggests that future studies in cirrhosis should be carried out exploring higher doses and longer durations of therapy.
Changing incidence of neural tube defects in Aegean Turkey
Authors: Çaglayan Suat , Kayhan Bülent , MentesLoglu Süreyya , Aksit Sadik
Published: April 2008

Summary. The incidence of neural tube defects was monitored among all live‐ and still‐births delivered between June 1986 and July 1988. In all there were 19115 total births. The incidence of neural tube defects (NTD) was 1.9 per 1000 among those whose conception time was prior to May 1986. However, in conceptions occurring in May, June and July 1986, the NTD rate increased to a level of 8.9 per 1000, subsequently gradually declining to previous levels within 9 months. This dramatic change in incidence, which parallels a previous finding from Turkey, suggests that this finding may be associated with the Chernobyl disaster of May 1986.
Childhood cancers and their association with pregnancy drugs and illnesses
Authors: Gilman Estelle A. , Margaret L. , Wilson Kinnier , Kneale G.W. , Waterhouse J.A.H.
Published: April 2008

Summary. In a case/control study of 8059 matched pairs, the effect of maternal exposure to drugs and illnesses during pregnancy on the relative risk (RR) of cancer in the child was investigated using conditional logistic regression techniques. Acute respiratory infections, particularly viral infections such as influenza, were associated with a significantly increased RR of all childhood cancers and of neoplasms of the reticuloendothelial system (RES) in particular, (RR = 1.69 all cancers, RR = 1.81 RES neoplasms, RR = 1.59 solid cancers). An analysis of illnesses according to their physiological effects yielded a significant association between childhood leukaemia and febrile illnesses (RR = 1.27 RES neoplasms). A significant increase in RR was associated with maternal history of epilepsy (RR = 1.31 all cancers) rather than with exposure to anticonvulsant drugs. Vaccines showed a pattern of RR similar to that of acute viral infections. Consumption of antipyretics and analgesics significantly increased the RR of childhood cancer (RR = 1.36 all cancers). An analysis of drugs according to their metabolic reactions yielded a significant association between those undergoing amino acid conjugation (predominantly antipyretics and analgesics) and childhood cancer risk (RR = 1.76 solid cancers).
Recent trends in the prevalence and secondary prevention of Down's syndrome
Authors: Stone David H. , Rosenberg Kathryn , Womersley John
Published: April 2008

Examination of data from the Glasgow Registry of Congenital Anomalies indicated that 184 infants with Down's syndrome were born (live or still) to mothers residing in the Greater Glasgow Health Board area between 1974 and 1986 inclusive. This represents a period prevalence of 1.1 per 1000 total births. Despite a strongly positive correlation between prevalence and maternal age, most of the Down's syndrome infants were born to mothers aged under 35 years. There was no evidence either of a recent decline in the annual prevalence rate or of a changing pattern of risk in relation to maternal age. Antenatal diagnosis resulted in the termination of less than a tenth of all Down's syndrome pregnancies. These findings point to a need for further aetiological research, for continued epidemiological monitoring, for an improvement in the relatively low uptake of amniocentesis by older mothers, and for the development of a screening test which can be offered to the entire pregnant population.
Antenatal and perinatal care in southern Italy. I. The mothers' reports
Authors: Quagliata Luigi , Scarpellino Benedetto , Mendes Claudia , Cafiero Maurizio , Coppol Angelo , Mazzarella Gianfranco , Pisacane Alfredo
Published: April 2008

Summary. A population‐based cross‐sectional study of antenatal and perinatal care was performed in Campania, a region of southern Italy. One thousand three hundred women who had given birth in 1982 were interviewed. The number of antenatal visits was very low, less than 1% of the mothers having attended more than three times during pregnancy. The women at high obstetric risk did not attend more than those at low risk and certain aspects of their antenatal care were unsatisfactory. The place of birth was similar for high risk and low risk mothers, with 40% delivering in small private facilities (with few neonatal resuscitation facilities and often with inadequate infant transport services). The labour was induced or accelerated in 60% of the mothers. The organisation of perinatal care did not take into account many of the needs of the mothers such as presence of a relative at delivery, ambulation during labour, early relationship with the newborn, rooming‐in, or encouragement to breastfeed.
Prenatal exposure to prescribed drugs in Tennessee Medicaid, 1983–1988
Authors: Piper Joyce M. , Mitchel Edward F.
Published: April 2008

Summary. This report describes the prenatal exposure histories of 107 804 women to prescribed drugs other than vitamins, iron and other minerals. The data were obtained from Tennessee Medicaid pharmacy files linked to birth and fetal death certificates for 1983–1988. The utility of these data to other investigators in predicting power or estimating sample size for studies of drug exposure in pregnancy associated with adverse birth outcomes is discussed.
The central New Jersey neonatal brain haemorrhage study: design of the study and reliability of ultrasound diagnosis
Authors: Pinto‐Martin Jennifer , Paneth Nigel , Witomski Thomas , Stein Irving , Schonfeld Steven , Rosenfeld David , Rose Walter , Kazam Elias , Kairam Ram , Katsikiotis Vasilis , Susser Mervyn
Published: April 2008

Summary. Over a 34‐month period, 1105 newborns weighing between 501 and 2000 g at birth were enrolled in a prospective study of the aetiology and consequences of neonatal brain haemorrhage. The three participating hospitals cared for approximately 85% of births in the study weight range in Middlesex, Monmouth and Ocean counties, New Jersey. Cranial ultrasonographic imaging through the anterior fontanelle was carried out at a mean age of 4.9 ± 2.2 hours, 25.5 ± 4.8 hours and 7.2 ± 0.8 days to detect haemorrhage and other brain lesions. In 93.2% of study infants, scans were read by two independent expert readers (blind to the clinical status of the child) with submission of the scan to a third reader in cases of disagreement. Confirmation of both presence or absence and, when present, scan of first diagnosis of germinal matrix and/or intraventricular haemorrhage (GM/IVH) by two independent readers was achieved in 76.3% of study infants. The first two readers agreed as to presence or absence of GM/IVH in 82.4% of infants (Kappa = 0.56). Interobserver agreement was affected by the reported scan quality and by the number of scans available, but not by the hospital of origin, race or birthweight of the infant.
Ethnic variation in postnatal assessments of gestational age: a reappraisal
Authors: Alexander Greg R. , de Caunest Francois , Hulsey Thomas C. , Tompkins Mark E. , Allen Marilee
Published: April 2008

Summary. While the possibility of an ethnic bias in postnatal assessments of gestational age has been suggested by several investigators, others have reported that postnatal assessments do not provide biased estimates in non‐White ethnic groups. In the light of this ongoing controversy, this study examines the validity of the Ballard postnatal assessment of gestational age by ethnicity, using a relatively large hospital data base that allows for the inspection of ethnic variations in the agreement between the Ballard assessment and last menstrual period (LMP). The results indicate that there is a greater over‐estimation of the LMP interval by the Ballard method in Blacks compared with Whites and suggest that systematic differences exist by ethnicity of mother in the agreement between the Ballard postnatal assessment and the LMP interval. After taking maternal characteristics and pregnancy complications into account, for a given gestational age interval, Blacks have on average a greater level of maturity as measured by Ballard. One interpretation of these findings is that postnatal assessments may provide biased overestimates of the LMP gestational age interval in certain ethnic groups. An alternative interpretation of these data is that the gestational age interval based on LMP is not a valid indicator of fetal maturity, readiness for birth and infant risk status across all ethnic groups.
Variations in family visiting policies in neonatal intensive care units in eleven EC countries
Authors: Reid Margaret , Andersen Else
Published: April 2008

Summary. The paper addresses the lack of information concerning parental visiting in neonatal intensive care units (NICU) across European Community (EC) countries. It reports on a study involving 11 EC countries and 38 units carried out under the auspices of a Concerted Action project. Information gathered from the 38 units yields data on the parental and family visiting policies. The study reveals a wide variation in the policies from considerable parental access to the infant in the NICU to restricted visiting. Policies concerned with unit facilities and unit support staff reflect the orientation of the overall unit policy with regard to visiting.
Gestational age and intrauterine growth retardation among white and black very low birthweight infants: a population‐based cohort study
Authors: Berg Cynthia J. , Zupan Jelka , D'Almada Philip J. , Khoury Muin J. , Fuller Lisa J.
Published: April 2008

Summary. Very low birthweight (VLBW) is a commonly used endpoint in perinatal epidemiology, but the population of VLBW infants comprises a wide range of gestational ages and rates of fetal growth. We used data from a population‐based study of all 1072 black and white VLBW liveborn infants born in 29 counties in Georgia between April 1986 and March 1988. Less than 1% of the VLBW infants were ≥ 37 weeks gestation; most were 29–32 weeks (26%) or 25 to 28 weeks (40%); 12% were 22 weeks or less. All infants 33 weeks gestation or greater were growth retarded. The population of VLBW infants seems to comprise three groups: approximately 11% very immature infants of 22 weeks or less; the majority of infants, born between 23 and 30 weeks, 90% of which are of normal weight for their gestational age; and a group of less premature, growth‐retarded infants from 31 to 36 weeks. We found little or no difference in the distribution of gestational age or the percentage of intrauterine growth rates (IUGR) between black and white infants. In the USA the VLBW rate among black infants is over three times greater than that among white infants and consequently the rates of the three types of VLBW among black infants are likely to be triple those among white infants.
Relationship between the incidence of sudden infant death syndrome (SIDS) and other causes of infant mortality in the industrialised countries
Authors: Kelmanson Igor A.
Published: April 2008

Summary. This study compared the incidence of sudden infant death syndrome (SIDS) in 12 industrialised countries during the 1980s with that of other known causes of infant mortality using WHO demographic data. Regression analysis showed a statistically significant negative relationship between registered SIDS rate and infant mortality rate, as a result of perinatal conditions. The results are discussed, and possible explanations are suggested.
The relationship between maternal skinfold thickness, smoking and birthweight in black and white women
Authors: Neggers Yasmin , Goldenberg Robert L. , Cliver Suzanne P. , Hoffman Howard J. , Copper Rachel L.
Published: April 2008

Summary. A prospective study was conducted in a sample of 1491 multiparous women to ascertain whether the relationship between maternal tricep skinfold thickness and infant birthweight is modified by smoking status and whether the relationship is different in white and black infants. Maternal tricep skinfold thickness measured at midpregnancy was a significant predictor of infant birthweight in both white and black infants after adjusting for gestational age at birth, maternal height, maternal age, parity, alcohol consumption and sex of the infant. However, maternal tricep skinfold thickness was a better predictor of birthweight in smokers compared with nonsmokers. Both white and black women with tricep skinfold thickness below the sample mean had lower infant birthweight than women with tricep skinfold at or above the mean, after adjusting for gestational age at birth, but the difference was greater in smokers (198 g for white and 221 g for black infants) than in nonsmokers (124 g for white and 120 g for black infants). These results suggest that maternal subcutaneous fat measured by tricep skinfold thickness has a greater effect on infant birthweight in smokers compared with nonsmokers, with similar effects in white and black infants.
Low birth weight as a determinant of infectious disease mortality: a methodological evaluation
Authors: Read Jennifer S. , Clemens John D.
Published: April 2008

Summary. Low birthweight (LBW) is cited as an important determinant of infectious disease mortality during infancy, both in developed and developing countries. We applied methodological standards to evaluate the scientific validity and clinical applicability of epidemiological studies of this relationship. Three published studies, all reporting an elevation of the risk of infectious disease mortality in infants born with LBW, were identified. Noteworthy methodological deficiencies found in one or more studies included failure to obtain objective data about birthweight and gestational age for a high proportion of study subjects, lack of explicit criteria for assigning causes of death, failure to safeguard against biases in assessment of cause of death and inadequate control for potential confounding variables. In addition, clinical application of the results of these studies was limited by lack of exploration of the roles of preterm birth vs. small‐for‐gestational‐age (SGA) birth, as well as by inattention to the role of congenital anomalies, in explaining the elevated risk. Although our evaluation does not necessarily negate the results of these studies, the failure of any of the studies to comply with all of the standards highlights the need for further research to provide credible evidence regarding the presence and strength of a relationship between LBW and infectious disease mortality in both developed and developing countries.
Influence of branched‐chain amino acid infusion on arterial concentrations and brain exchange of amino acids in patients with hepatic cirrhosis
Authors: Sato Yuzo , Eriksson Siw , Hagenfeldt Lars , Wahren John
Published: April 2008

Summary.

The influence of branched‐chain amino acid (BCAA) infusion on arterial concentrations and brain exchange of amino acids was studied in seven patients with hepatic cirrhosis and in six healthy control subjects. Arterial levels and arterial‐jugular venous (A‐JV) concentration differences for amino acids, glucose, ketone bodies and lactate were measured in the basal state and during a constant rate, 150 min intravenous infusion of a BCAA solution (250 fmiol/min, 70% L‐leucine, 20% L‐valine and 10% L‐isoleucine).

In the basal state the arterial whole blood concentrations of tyrosine, phenylalanine and methionine were 40–130 % higher in the cirrhotic patients compared to the controls, while the levels of the BCAA were 20–35 % lower. The patients' concentration of aspartic acid was 70% below the corresponding control value.

During BCAA infusion the arterial leucine concentration rose 4–5 fold while valine increased 60–95% and isoleucine rose 45–50%. The arterial levels of several amino acids decreased progressively in a similar manner in patients and controls. At the end of the 150 min infusion period methionine had decreased 35% (P<001), tyrosine 25% (P<0–001) and phenylalanine 35% (P<0–001) in the patient group.

Positive A‐JV differences in amino acid concentration–indicating net brain uptake–were seen for leucine, isoleucine, valine, serine, tyrosine and lysine in both groups in the basal state. The patients had a greater A‐JV difference than the controls for tyrosine (P<0–05) while the uptake of the other amino acids, including the BCAA, was similar in the two groups. The fractional uptake of leucine and valine was significantly increased in the patients.

During BCAA infusion the A‐JV difference for leucine increased 2–3 fold in both patients and controls and the net uptake to the brain of tyrosine and phenylalanine was abolished in the patient group.

It is concluded that (a) patients with hepatic cirrhosis show a decreased whole blood concentration of aspartate indicating a reduced intracellular concentration of this amino acid, (b) brain uptake of tyrosine and fractional uptake of leucine and valine is augmented in patients with hepatic cirrhosis, demonstrating abnormal brain amino acid uptake in this disorder, and (c) BCAA infusion effectively lowers the arterial concentrations for tyrosine, phenylalanine and methionine in cirrhotic patients as well as in healthy controls and blocks the abnormal brain uptake of tyrosine. These findings provide a biochemical background to the suggested beneficial effect of BCAA infusion in patients with hepatic cirrhosis and portal systemic encephalopathy.
A simple and reliable method for determination of skin perfusion pressure in patients with severe occlusive arterial disease
Authors: Støckel Mikael , Brøchner‐Mortensen Jens
Published: April 2008

Summary. In an attempt to simplify the pre‐operative assessment of amputation level in patients with severe occlusive arterial disease of the legs the skin perfusion pressure (SPPi) on calf and/or thigh was determined photo‐electrically in 38 patients, aged 41–85 years and compared to the pressure values (SPPi) determined by the widely used but cumbersome isotope washout technique. SPPi was determined as the minimal external counter pressure (applied by a blood pressure cuff) sufficient to stop the washout from an intracutaneous depot of Na131I‐ mixed with histamine. SPPP was determined as the minimal external counter pressure required to prevent skin reddening after blanching of the skin. The systolic blood pressure, determined indirectly by strain gauge technique at the same level of the leg, was used for reading the SPPP as that counter pressure at which the photo‐electric tracing moves away from a straight line placed on the tracing through the counter pressure corresponding to the systolic blood pressure. In the studied range 18–88 mmHg there was no significant difference between SPPP and SPPi. The total day‐to‐day variation of SPPP, determined from ten double determinations in eight patients was 6‐6 mmHg (range of SPPP: 23–80 mmHg). The present results indicate that assessment of amputation level from SPPp using the standardized reading should offer a reliable alternative to the isotope washout method. The photo‐electric technique is simple and fast, and gives only negligible discomfort to the patient.
Vibration sense and sympathetic vasoconstrictor activity in patients with occlusive arterial disease
Authors: Bjerre‐Jepsen K. , Henriksen O. , Parm M. , Agerskov K. , Tønnesen K. H.
Published: April 2008

Summary. The function of sympathetic vasoconstrictor fibres was studied in 18 patients with occlusive arterial disease of the legs and somatic neuropathy, as evidenced as an increased vibration perception threshold. Nine patients suffered from long‐term diabetes mellitus. Sympathetic vasoconstrictor function was studied by the capability of the local sympathetic venoarteriolar reflex (Henriksen 1977) elicited by lowering the leg to induce an arteriolar constriction in subcutaneous tissue at the ankle level. Blood flow was measured by the local isotope washout technique. In only five patients with loss of vibration sense, abnormal vasoconstrictor function was found. In three of these patients, the abnormal response most likely could be ascribed to impaired function of the vascular smooth muscle cells.

Neither in diabetics nor in non‐diabetics could an abnormal vibration sense be taken as evidence for loss of sympathetic vasoconstrictor function. It is suggested that this is studied by a simple postural test as used in the present study.
The effects of naloxone on circulating metabolites, glycoregulatory hormones and gut peptides during pelvic surgery
Authors: Hall G. M. , Adrian T. E. , Bloom S. R. , Mashiter K.
Published: April 2008

Summary. The role of endogenous opioid peptides in mediating the endocrine and metabolic response to pelvic surgery was investigated. Fourteen patients were studied; seven were infused with the specific opioid antagonist, naloxone, at a rate of 20 μg kg‐1 (body weight) hr‐1, while the remainder acted as a control group.

Naloxone exacerbated the glycaemic response to surgery but had no statistically significant effect on changes in the glycoregulatory hormones, pancreatic glucagon, insulin, cortisol and growth hormone. However, there was a wide individual variation in the glucagon response to naloxone with marked stimulation in some patients. Naloxone infusion increased plasma pancreatic polypeptide secretion during the 1st hour of surgery and reversed the decline in plasma motilin concentrations, but had no effect on circulating somatostatin, vasoactive intestinal polypeptide, gastrin, enteroglucagon and neurotensin values. We conclude that endogenous opioid peptides have only a limited role in modulating the endocrine and metabolic response to surgery.
Effect of the degree and speed of tilt on the immediate heart rate reaction
Authors: Sundkvist Göran , Lilja Bo
Published: April 2008

Summary. The effect of the degree and speed of tilt on the immediate heart rate reaction measuring cardiac autonomic nerve function was evaluated in nine healthy subjects. The results showed that the tilt angle determined the immediate increase in heart rate. The increase in heart rate was maximal when a 90° tilt was performed. After the immediate increase there was a transient decrease in heart rate after rapid tilts (2–5 s). A rapid 90° tilt is preferred when automatic nerve function should be evaluated from the immediate heart rate response.
An evaluation of a duodenal perfusion technique in human studies
Authors: Björnsson Ó. G. , Fletcher D. R. , Chadwick V. S.
Published: April 2008

Summary. A retrospective evaluation was carried out on the standard duodenal perfusion technique in human subjects. Polyethylene glycol (PEG 4000), non‐labelled or labelled with 14C, and phenol red were used as duodenal and gastric recovery markers, respectively. The evaluation was limited to the 2‐h equilibration period in each study. The studies were carried out on the subjects sitting in an armchair. Multi‐perforated wide‐bore aspiration tubes accompanied with air ventiles were used for duodenal and gastric aspiration. High perfusion flow rates (≤ 13·5 ml min‐1) and a long perfusion segment (15–20 cm) were applied in the duodenum and the collection periods were kept short. An efficient gastric and duodenal aspiration was obtained in most studies with a limited gastro‐duodenal and duodeno‐gastric flux. On average, the fluctuations in concentration of the duodenal marker (PEG 4000) (‘steady state’), expressed as a coefficient of variation (CV), were 13·1± 1·0% (SEM, n=66). Correlation analysis suggested that the ‘steady state’ conditions in the duodenum were improved by an efficient gastric and duodenal aspiration and a high perfusion flow rate. This was supported by an inverse correlation found between the magnitude of the gastro‐duodenal flux and the marker's fluctuations, the efficiency of the gastric aspiration and the magnitude of the gastro‐duodenal flux, and the efficiency of the duodenal aspiration and the magnitude of the duodeno‐gastric flux. A high correlation was found between the two duodenal perfusion markers used, PEG 4000 and 14C PEG 4000.
Is there a change in relative muscle fibre composition with age?
Authors: Grimby G. , Aniansson A. , Zetterberg C. , Saltin B.
Published: April 2008

Summary. Muscle biopsy was taken from the vastus lateralis muscle during surgery of recent fractures of the neck of the femur in 52 patients aged 66–100 years. The percentage of slow twitch (ST) fibres was close to 55% with no significant change with age and no difference between patients with and without clinical diagnoses prior to the fracture. Also subgrouping of fast twitch (FT) fibres showed insignificant changes in this age range. Muscle fibre areas were smaller for FT than for ST fibres. A comparison between proximal and distal sampling site in the muscle did not show any significant difference. Combining these results and previous results from our laboratories no change in relative fibre composition with age could be proven.