Biological applications of cryo-soft X-ray tomography.

X-rays are used for imaging many different types of biological specimen, ranging from live organisms to the individual cells and proteins from which they are made. The level of detail achieved as a result of the imaging varies depending on both the sample and the technique used. One of the most recent technical developments in X-ray imaging is that of the soft X-ray microscope, designed to allow the internal structure of individual biological cells to be explored. With a field of view of ∼10-20 × âˆ¼10-20 µm, a penetration depth of ∼10 µm and a resolution of ∼40 nm(3), the soft X-ray microscope neatly fits between the imaging capabilities of light and electron microscopes.

Parental needs among children with birth defects: defining a parent-to-parent support network.

The objective of this study was to explore how a parent-to-parent support network could impact parents of a child with a structural birth defect by specifically looking at parents' continued needs, aspects influencing their participation in support networks, and their recommendations. Structural birth defects occur in approximately 3 % of all infants, representing a significant public health issue. For many reasons, parents are uniquely qualified to provide support to each other. Data were collected retrospectively through a qualitative approach of focus groups or one-on-one interviews. Thirty one parents of infants registered in the Utah Birth Defect Network participated in the study. Three themes emerged, "current sources and inconsistencies in parent-to-parent-support," "aspects that influence participation in parent-to-parent network," and "recommendations for a parent-to-parent program." Health care providers need to be aware of the services and inform parents about these options. A statewide parent-to-parent network integrated into all hospitals would be a valuable resource to facilitate sharing of issues related to caring for an infant or child with a birth defect.

Age of acquisition, not word frequency affects object recognition: evidence from the effects of visual degradation.

Four experiments examined how age of acquisition (AoA) and word frequency (WF) interact with manipulations of image quality in a picture-naming task. Experiments 1 and 2 examined the effect of overlaying the to-be-named picture with irrelevant contours. The magnitude of the AoA effect increased when the contours were added (Experiment 1), but the effect of WF remained constant (Experiment 2). Experiments 3 and 4 examined the effects of reducing the contrast of the contours defining the to-be-named picture. Both the effects of AoA (Experiment 3) and WF (Experiment 4) remained constant in the face of contrast reduction. These results provide an empirical dissociation of the effects of AoA and WF. The results are consistent with the idea that both AoA and the addition of irrelevant contours affect the efficiency of object recognition, but WF affects later processes involved in retrieval of object names. The theoretical implications of these findings in relation to accounts of AoA and frequency and their functional localisation in the lexical system are discussed.

Improved molecular diagnosis of dystrophinopathies in an unselected clinical cohort.

Mutations in the DMD gene result in Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD). Readily available clinical tests detect only deletions of one exon or greater, which are found in approximately 60% of cases. Mutational analysis of other types of DMD mutations, such as premature stop codons and small frameshifting insertions or deletions, has historically been hampered by the large size of the gene. We have recently reported a method that allows the rapid and economical sequencing of the entire coding region of the DMD gene, and that is more sensitive than methods based on single-strand conformational polymorphism (SSCP) screening or other preliminary screening steps. Here we use single condition amplification/internal primer (SCAIP) sequencing analysis, in combination with multiplex amplifiable probe hybridization (MAPH) analysis of duplications, to report the frequency of mutations in a large cohort of unselected dystrophinopathy patients from a single clinic. Our results indicate that 7% of dystrophinopathy patients do not have coding region mutations, suggesting that intronic mutations are not uncommon. The availability of rapid and thorough mutation analysis from peripheral blood samples, along with an improved estimate of the percentage of non-coding region mutations, will be of benefit for improved genetic counseling and in identification of cohorts for clinical trials.

Development of combined imbibition and hydrothermal threshold models to simulate maize (Zea mays) and chickpea (Cicer arietinum) seed germination in variable environments.

* The ability of hydrothermal time (HTT) and virtual osmotic potential (VOP) models to describe the kinetics of maize (Zea mays) and chickpea (Cicer arietinum) seed germination under variable conditions of water potential was investigated with a view to gaining an improved understanding of the impact of on-farm seed priming on seedling establishment through simulation. * Germination and/or imbibition time courses were recorded over a wide range of constant temperatures and water potentials and simple stepwise changes in water potential. * Both models adequately described germination under constant environmental conditions, but not conditions of water potential that varied. To test the hypothesis that this inaccuracy resulted from the use of ambient water potential, a parsimonious model of seed imbibition was developed to calibrate the HTT and VOP models (IHTT and IVOP) and drive them with estimates of seed water potential. * The IHTT and IVOP models described germination during stepwise changes in water potential more accurately than the conventional models, and should contribute to improved predictions of germination time in the field.

Congenital malformations of the diaphragm: findings of the West Midlands Congenital Anomaly Register 1995 to 2000.

OBJECTIVES: To describe trends in incidence, associated anomalies, clinical outcomes and sensitivity of prenatal diagnosis for congenital malformations of the diaphragm in the West Midlands Region between 1995 and 2000. METHODS: Information was retrieved from a population-based register of major congenital malformations in a health region of England, the West Midlands Congenital Anomaly Register (WMCAR), between 1995 and 2000. RESULTS: One hundred and sixty-one confirmed cases of congenital malformations of the diaphragm were notified from 396 577 births. This gives an incidence of 4.1 per 10,000 births. After natural losses and terminations, the incidence at birth was 2.9 per 10,000 registered births. For live-born cases, the infant mortality rate was 317 per 1000 births. 47% of the cases had additional structural or chromosomal anomalies; the infant mortality rate for these complex cases was 533 per 1000, an increased relative risk of 2.37 compared with isolated lesions. 66% of the cases were diagnosed prenatally, 51% of isolated lesions and 84% of complex cases. Fourteen prenatally diagnosed cases (12%) were false-positives; however, 11 of these cases had other significant pathology. These 14 cases were not included in the 161 confirmed cases. CONCLUSION: Congenital malformations of the diaphragm remain associated with considerable infant mortality. Most cases are now diagnosed before birth and the prognosis is adversely affected by the presence of other structural or chromosomal anomalies. This presents significant challenges for those involved in counselling the parents of affected fetuses.

Pure trisomy 10p resulting from an extra ring chromosome: characterization by methods of advanced molecular cytogenetics.

With the use of advanced molecular cytogenetic techniques, we have identified an extra ring chromosome consisting of the entire short arm of chromosome 10 (10p) in a 9-month-old girl with multiple congenital anomalies. This case represents another cytogenetic mechanism leading to the formation of pure complete trisomy 10p, which has not been reported previously. Pure trisomy 10p is rare. This case will further delineate those features associated with trisomy 10p.

Neuroticism is not associated with the serotonin transporter (5-HTTLPR) polymorphism.

A deletion/insertion polymorphism in the transcriptional control region of the serotonin transporter gene (5-HTTLPR) was reported to be associated with dimensional measures of neuroticism, although subsequent replication attempts have failed. These replication attempts, however, have been dissimilar to the initial study in sample size, distribution of allelic frequency and/or assessment of neuroticism. The current study was conducted in a further attempt to replicate the initial finding using: (a) a sample that was more comparable to each of the individual samples in the initial report; and (b) identical psychometric methodology to assess neuroticism. Two hundred and twenty-five Caucasian adults were genotyped for the 5-HTTLPR polymorphism and completed the NEO Personality Inventory. Results did not replicate the association between the 5-HTTLPR polymorphism and neuroticism; individuals with the short form of this variant did not report higher NEO Neuroticism. Indeed, men with the short form reported lower Anxiety, a finding that is directionally opposite to the initial results. These findings, combined with other failures to replicate, indicate that the reproducibility of the association between the 5-HTTLPR polymorphism and neuroticism must be regarded as questionable. The contradictory findings suggest the need for a replication attempt in a large, normative sample that is stratified by ethnicity and sex.

Aggression and anger-related traits associated with a polymorphism of the tryptophan hydroxylase gene.

BACKGROUND: Central nervous system (CNS) serotonergic activity correlates inversely with human aggressive behavior, and individual differences in aggressive disposition are at least partially heritable. This study was conducted to evaluate the possible association between measures of antagonistic behavior and an intronic polymorphism of the gene coding for tryptophan hydroxylase (TPH), the rate-limiting enzyme in serotonin biosynthesis. METHODS: Locally recruited men and women (n = 251) were genotyped for the A218C polymorphism located in intron 7 of the TPH gene. All subjects were administered standard interview and questionnaire indices of aggression and anger-related traits of personality; in a portion of subjects, CNS serotonergic activity was assessed by neuropsychopharmacologic challenge (prolactin response to fenfluramine hydrochloride). RESULTS: Persons having any TPH U allele scored significantly higher on measures of aggression and tendency to experience unprovoked anger and were more likely to report expressing their anger outwardly than individuals homozygous for the alternate L allele. In men, but not women, peak prolactin response to fenfluramine was also attenuated among subjects having any U allele, relative to LL homozygotes. CONCLUSIONS: Individual differences in aggressive disposition are associated with an intronic polymorphism of the TPH gene in a nonpatient sample of community-derived volunteers.

Correlation of cellular differentiation in human colorectal carcinoma and adenoma cell lines with metabolite profiles determined by 1H magnetic resonance spectroscopy.

The aim was to determine whether proton magnetic resonance spectroscopy (MRS) could grade human colorectal cells of differing malignant potential. A cell model of tumour development and progression comprising 2 non-tumorigenic adenoma lines and 4 carcinoma lines of increasing tumorigenicity was chosen. A gradual reduction in cellular differentiation and an accumulation of genetic alterations from adenoma to carcinoma characterized the selected cell lines. One-dimensional and 2-dimensional MRS showed that reduced differentiation in the cell model correlated with an increase in the levels of lipid, metabolites, the glycosylation intermediate uridine diphospho-N-acetylglucosamine and cell-surface fucosylation. Mutations involving the K-ras, APC and DCC genes are present both in adenoma- and in carcinoma-derived lines in this model, but the first evidence of an abnormality in the p53 gene was concomitant with the cells' ability to grow as a tumour in athymic nude mice. This genetic change coincided with the detection, by MRS, of UDP-hexose (ribose moiety, 2D MRS cross peak between H2 at 4.38 ppm and HI at 5.99 ppm) and the appearance of an additional fucosyl resonance (cross peak between-CH3 at 1.41 and H5 at 4.30 ppm) in the least tumorigenic of the carcinoma cell lines. An increase in complexity of the fucosylation spectral pattern was observed with further cellular de-differentiation and increased tumorigenicity. Collectively these data support the existence of an adenoma-carcinoma sequence.