Electron Optics

Contains reports on two research projects.Joint Services Electronics Program (Contract DAAB07-75-C-1346

Developing Retina and PNS Segments for Transplantation Into the Adult Host Eye: Reconstruction of the Mammalian Visual System. 1. Methodology

Various techniques have been explored to determine the uses and limitations of techniques that enable the adult CNS to regenerate, but relatively little attention has been given to the consideration of a "reconstructed" visual system. Using this approach, one can design experiments to study the uses of exogenous tissues in reestablishing neuronal circuits that have been damaged. Toward this end, experiments were designed to determine whether embryonic retinal ganglion cells can project axons into a grafted PNS "bridge", and enter adult host targets that were partially deafferented. Embryonic eyes of E11, E14, E18 and E21 rats were sutured to peripheral nerve segments which served as bridges between the host eye and frontal cortex. Projections between the developing retina and the host brain could then be evaluated using HRP tracing techniques. From a methodological standpoint, the preparations are 65% effective; i.e., a viable bridge results between the embryonic eye and the host forebrain. The results presented in the accompanying paper demonstrate that the technique can yield results indicative of embryonic retinal development and axonal projection through the graft and into the host brain. This partial reconstruction of the visual system may prove a useful tool in understanding the uses and limitations of grafting in the CNS

PTPRC (CD45) is not associated with multiple sclerosis in a large cohort of German patients

BACKGROUND: Since contradictory results have been reported, we reanalysed the 77C→G transition in exon 4 of the protein-tyrosine phosphatase receptor-type C (PTPRC also known as CD45) in a large cohort of German MS patients and controls. Different isoforms of the protein are expressed, depending on alternative splicing of exons 4 (CD45RA), 5 (CD45RB) and 6 (CD45RC) (CD45RO, exons 4–6 spliced out). The 77C→G transition does not change the amino acid sequence, but it is probably part of a motif necessary for splicing leading to the isoform CD45RA. The expression of CD45RA is increased in 77C/G heterozygous individuals. The aim of the study was to clarify the importance of the PTPRC 77C→G transition in our German cohort of MS patients. METHODS: PCR products of exon 4 were digested using endonuclease MspI. The resulting restriction fragments of the wildtype C allele are 198 and 62 bp in length. In the G allele an additional restriction site is present yielding fragments of 114 and 84 bp. RESULTS: The G allele was identified in 10 of the 347 controls (1.4%) and in 7 of 454 MS patients (0.8%; Table 1). No homozygous individuals were found either in the control or in the patient group. Genetic association between the PTPRC 77C→G transition and MS susceptibility was excluded in the MS cohort. In addition, subgrouping patients according to differences in the clinical course of MS or according to HLA-DRB1*15 status did not yield significant differences. CONCLUSIONS: The 77C→G transition in exon 4 of the PTPRC gene may contribute to MS susceptibility only in very few families, if at all, but it is not relevant for the majority of MS cases, including virtually all German patients

Lymphedema in a 7-year-old boy infected with Wuchereria bancrofti in Sierra Leone: A case report

We present a case of congenital lymphedema in a 7-year-old boy in Sierra Leone with active filarial infection and penile edema. The genital edema with onset at 6 months of age may have been due to a congenital abnormality in lymphatic drainage. Other possible causes of childhood lymphedema, including Milroy's disease, are discussed

Objective measures for the assessment of post-operative pain in bos indicus bull calves following castration

The aim of the study was to assess pain in Bos indicus bull calves following surgical castration. Forty-two animals were randomised to four groups: no castration (NC, n = 6); castration with pre-operative lidocaine (CL, n = 12); castration with pre-operative meloxicam (CM, n = 12); and, castration alone (C, n = 12). Bodyweight was measured regularly and pedometers provided data on activity and rest from day −7 (7 days prior to surgery) to 13. Blood was collected for the measurement of serum amyloid A (SAA), haptoglobin, fibrinogen, and iron on days 0, 3 and 6. Bodyweight and pedometry data were analysed with a mixed effect model. The blood results were analysed with repeated measure one-way analysis of variance (ANOVA). There was no treatment effect on bodyweight or activity. The duration of rest was greatest in the CM group and lowest in the C group. There was a significant increase in the concentrations of SAA, haptoglobin, and fibrinogen in all of the groups from day 0 to 3. Iron concentrations were not different at the time points it was measured. The results of this study suggest that animals rest for longer periods after the pre-operative administration of meloxicam. The other objective assessments measured in this study were not able to consistently differentiate between treatment groups

The influence of C3 and C4 vegetation on soil organic matter dynamics in contrasting semi-natural tropical ecosystems

This is a freely-available open access publication. Please cite the published version which is available via the DOI link in this record.Variations in the carbon isotopic composition of soil organic matter (SOM) in bulk and fractionated samples were used to assess the influence of C3 and C4 vegetation on SOM dynamics in semi-natural tropical ecosystems sampled along a precipitation gradient in West Africa. Differential patterns in SOM dynamics in C3/C4 mixed ecosystems occurred at various spatial scales. Relative changes in C/ N ratios between two contrasting SOM fractions were used to evaluate potential site-scale differences in SOM dynamics between C3- and C4-dominated locations. These differences were strongly controlled by soil texture across the precipitation gradient, with a function driven by bulk δ 13C and sand content explaining 0.63 of the observed variability. The variation of δ 13C with soil depth indicated a greater accumulation of C3-derived carbon with increasing precipitation, with this trend also being strongly dependant on soil characteristics. The influence of vegetation thickening on SOM dynamics was also assessed in two adjacent, but structurally contrasting, transitional ecosystems occurring on comparable soils to minimise the confounding effects posed by climatic and edaphic factors. Radiocarbon analyses of sand-size aggregates yielded relatively short mean residence times (τ ) even in deep soil layers, while the most stable SOM fraction associated with silt and clay exhibited shorter τ in the savanna woodland than in the neighbouring forest stand. These results, together with the vertical variation observed in δ 13C values, strongly suggest that both ecosystems are undergoing a rapid transition towards denser closed canopy formations. However, vegetation thickening varied in intensity at each site and exerted contrasting effects on SOM dynamics. This study shows that the interdependence between biotic and abiotic factors ultimately determine whether SOM dynamics of Published by Copernicus Publications on behalf of the European Geosciences Union. 5042 G. Saiz et al.: Influence of C3/C4 on SOM in tropical biomes C3- and C4-derived vegetation are at variance in ecosystems where both vegetation types coexist. The results highlight the far-reaching implications that vegetation thickening may have for the stability of deep SOM.UK National Environment Research CouncilAustralian Institute of Nuclear Science and Engineering (AINSE Ltd

Dropout in a longitudinal, cohort study of urologic disease in community men

BACKGROUND: Reasons for attrition in studies vary, but may be a major concern in long-term studies if those who drop out differ systematically from those who continue to participate. Factors associated with dropout were evaluated in a twelve-year community-based, prospective cohort study of urologic disease in men. METHODS: During 1989–1991, 2,115 randomly selected Caucasian men, ages 40–79 years from Olmsted County, Minnesota were enrolled and followed with questionnaires biennially; 332 men were added in follow-up. A random subset (~25%) received a urologic examination. Baseline characteristics including age, benign prostatic hyperplasia (BPH) symptoms, comorbidities, and socioeconomic factors were compared between subjects who did and did not participate after the twelfth year of follow-up. RESULTS: Of the 2,447 men, 195 died and were excluded; 682 did not participate in 2002. Compared with men in the 40–49 year age group, men ≥ 70 years of age at baseline had a greater relative odds of dropout, 2.65 (95% CI: 1.93, 3.63). In age-adjusted analyses, relative to men without stroke, men who had suffered a stroke had a higher odds of dropout, age-adjusted OR 3.07 (95% CI: 1.49, 6.33). Presence of at least one BPH symptom was not associated with dropout, (age-adjusted OR 1.12 (95% CI: 0.93, 1.36)). CONCLUSION: These results provide assurance that dropout was not related to primary study outcomes. However, factors associated with dropout should be taken into account in analyses where they may be potential confounders