Development and characterisation of an irradiation device for biomedical studies covering the solar spectrum with individual regulated spectral bands.

To understand the importance of terrestrial solar exposure on human skin, not only individual spectral components need to be considered in biomedical studies, but also the relevance of the combined action profile of the complete solar spectrum (cSS) must be established. We therefore developed a novel irradiation device that combines the emission of four individual lamps (UVB, UVA, VIS and nIR) to achieve exposure from 280 to 1400 nm with individual controllable lamps. The integrated irradiance of each spectral band is similar to the solar spectrum. The lamps can be utilised individually or in any desired combination. Here we present the design, realisation, and validation of this irradiation device as well as biological results on cellular metabolism (MTT assay), cell cycle alterations, and clonogenic growth in HaCaT cells after exposures to the individual spectral bands as well as their simultaneous combinations. Thereby, we demonstrate that UVB combined with UVA is the main determinant for the metabolic activity within cSS. Also, UVB-dependent effects dominate cell cycle regulation in cSS, whilst UVA and nIR have little influence. Lastly, also clonogenic growth is dominated by the UVB action profile in cSS, despite nIR showing modulatory activity when applied in combination with UVB. Together, this highlights the regulatory influence of the different spectral bands on the three biological endpoints and demonstrates their modulation when being part of the complete solar spectrum.

Unsupervised Performance of the CogState Brief Battery in the Brain Health Registry: Implications for Detecting Cognitive Decline.

INTRODUCTION: The feasibility and validity of unsupervised, longitudinal brief computerized cognitive batteries is unknown. METHODS: Participants aged 56-90 (N = 19476) from the Brain Health Registry (BHR) completed the CogState Brief Battery (CBB) at 6-month intervals over a period of 5 years. We used linear mixed-effects models to assess whether cross-sectional and longitudinal performance on CBB within BHR was associated with demographic and cognitive characteristics. We also defined a group of CBB decliners based on subject-specific slopes and estimated associations between decliner status and participant characteristics. RESULTS: We found weak associations between longitudinal change in CBB and participant characteristics. Cross-sectional CBB scores were significantly associated with participant characteristics such as age, gender, ethnicity, self-reported disease status, and memory concern. CBB decliners were more likely to self-report mild cognitive impairment (MCI) and memory concerns. DISCUSSION: Cross-sectional, remote CBB shows evidence of construct validity, but our results suggest that longitudinal assessment may not provide additional value for identifying those at risk for and with cognitive impairment.

Longitudinal Comparison of in Clinic and at Home Administration of the Cogstate Brief Battery and Demonstrated Practice Effects in the Mayo Clinic Study of Aging.

BACKGROUND: The Cogstate Brief Battery (CBB) is a computerized cognitive assessment that can be completed in clinic or at home. Design/Objective: This retrospective study investigated whether practice effects / performance trajectories of the CBB differ by location of administration. PARTICIPANTS/SETTING: Participants included 1439 cognitively unimpaired individuals age 50-75 at baseline participating in the Mayo Clinic Study of Aging (MCSA), a population-based study of cognitive aging. Sixty three percent of participants completed the CBB in clinic only and 37% completed CBB both in clinic and at home. MEASUREMENTS: The CBB consists of four subtests: Detection, Identification, One Card Learning, and One Back. Linear mixed effects models were used to evaluate performance trajectories in clinic and at home. RESULTS: Results demonstrated significant practice effects between sessions 1 to 2 for most CBB measures. Practice effects continued over subsequent testing sessions, to a lesser degree. Average practice effects/trajectories were similar for each location (home vs. clinic). One Card Learning and One Back accuracy performances were lower at home than in clinic, and this difference was large in magnitude for One Card Learning accuracy. Participants performed faster at home on Detection reaction time, although this difference was small in magnitude. CONCLUSIONS: Results suggest the location where the CBB is completed has an important impact on performance, particularly for One Card Learning accuracy, and there are practice effects across repeated sessions that are similar regardless of where testing is completed.

Is Early Treatment with a Cervical Pessary an Option in Patients with a History of Surgical Conisation and a Short Cervix?

Objective: Patients with a history of one or more conizations have an increased risk of spontaneous preterm birth (SPTB). The aim of this study was to investigate the outcome of pregnancies in patients with a history of conization and early treatment with a cervical pessary. Methods: In this pilot observational study we included 21 patients and evaluated the obstetric history, the interval between pessary placement and delivery, gestational age at delivery, the neonatal outcome and the number of days of maternal and neonatal admission. Results: Among the study group of 21 patients, 20 patients had a singleton and one had a dichorionic/diamniotic twin pregnancy. At insertion, the mean gestational age was 17 + 2 (10 + 5-24 + 0) weeks and the mean cervical length was 19 (4-36) mm. Six patients presented with funneling at insertion with a mean funneling width of 19.7 (10-38) mm and funneling length of 19.9 (10-37) mm. Five patients had already lost at least one child due to early spontaneous preterm birth and another five had at least one previous abortion, who have now delivered beyond 34 weeks. The mean gestational age at delivery was 38 (31 + 1-41 + 0) gestational weeks and the mean interval between insertion and delivery was 145 (87-182) days. Conclusion: Our findings suggest a beneficial effect of an early pessary placement for patients at high-risk for preterm birth due to conization.

Distinct profiles of brain and cognitive changes in the very old with Alzheimer disease.

OBJECTIVE: To determine whether age-standardized brain morphometric and cognitive profiles differ in young-old (aged 60-75 years) and very-old (aged 80-91 years) patients with Alzheimer disease (AD). METHODS: Using a case-control retrospective design, we compared hippocampal volume and cortical gray matter thickness in areas known to be affected by AD in 105 patients with AD and 125 healthy control (HC) participants divided into young-old and very-old subgroups. Brain morphometric and cognitive scores of the AD groups were standardized to their respective age-appropriate HC subgroup and then compared. RESULTS: Several cognitive domains (executive function, immediate memory, and attention/processing speed) were less abnormal in the very old with AD than in the young old with AD. Similarly, the very old with AD showed less severe cortical thinning than the young old with AD in the left posterior cingulate cortex, right lateral temporal cortex, and bilateral parietal cortex and in overall cortical thickness. This effect is partially explained by an age-related decrease in cortical thickness in these brain regions in the HC participants. CONCLUSIONS: The typical pattern of AD-related cognitive and morphometric changes seen in the young old appear to be less salient in the very old. Thus, mild cases of AD in the very old may go undetected if one expects to see the prototypical pattern and severity of cognitive or brain changes that occur in the young old with AD. These results underscore the importance of interpreting neuropsychological test performance and morphometric brain measures in reference to the individual's age.

Decreased white matter integrity in late-myelinating fiber pathways in Alzheimer's disease supports retrogenesis.

The retrogenesis model of Alzheimer's disease (AD) posits that white matter (WM) degeneration follows a pattern that is the reverse of myelogenesis. Using diffusion tensor imaging (DTI) to test this model, we predicted greater loss of microstructural integrity in late-myelinating WM fiber pathways in AD patients than in healthy older adults, whereas differences in early-myelinating WM fiber pathways were not expected. We compared 16 AD patients and 14 demographically-matched healthy older adults with a whole-brain approach via tract-based spatial statistics (TBSS), and a region of interest (ROI) approach targeting early-myelinating (posterior limb of internal capsule, cerebral peduncles) and late-myelinating (inferior longitudinal fasciculus [ILF], superior longitudinal fasciculus [SLF]) fiber pathways. Permutation-based voxelwise analysis supported the retrogenesis model. There was significantly lower fractional anisotropy (FA) in AD patients compared to healthy older adults in late-myelinating but not early-myelinating pathways. These group differences appeared to be driven by loss of myelin integrity based on our finding of greater radial diffusion in AD than in healthy elderly. ROI analyses were generally in agreement with whole-brain findings, with significantly lower FA and increased radial diffusion in the ILF in the AD group. Consistent with the retrogenesis model, AD patients showed demonstrable changes in late-myelinating WM fiber pathways. Given greater change in the ILF than the SLF, wallerian degeneration secondary to cortical atrophy may also be a contributing mechanism. Knowledge of the pattern of WM microstructural changes in AD and its underlying mechanisms may contribute to earlier detection and intervention in at-risk groups.

Using the Lac repressor system to identify interacting proteins.

The present protocol describes a series of procedures to identify peptides interacting with PDZ domains. It is conceivable that the procedures can be applied to other purified protein modules or intact proteins without substantial modifications. With the deduced consensus combined with sequence information, it is possible to identify proteins present in the database with compatible sequences. If the expression of target protein and potential interacting candidate overlap temporally and spatially, biochemical and molecular experiments can be designed to study their physical and functional interactions.

Fine-resolution mapping by haplotype evaluation: the examples of PFIC1 and BRIC.

Loci for two inherited liver diseases, benign recurrent intrahepatic cholestasis (BRIC) and progressive familial intrahepatic cholestasis type 1 (PFIC1), have previously been mapped to 18q21 by a search for shared haplotypes in patients in two isolated populations. This paper describes the use of further haplotype evaluation with a larger sample of patients for both disorders, drawn from several different populations. Our assessment places both loci in the same interval of less than 1 cM and has led to the discovery of the PFIC1/BRIC gene, FIC1; this discovery permits retrospective examination of the general utility of haplotype evaluation and highlights possible caveats regarding this method of genetic mapping.

The kinetic cycle of cardiac troponin C: calcium binding and dissociation at site II trigger slow conformational rearrangements.

The goal of this study is to characterize the kinetic mechanism of Ca2+ activation and inactivation of cardiac troponin C (cTnC), the Ca2+ signaling protein which triggers heart muscle contraction. Previous studies have shown that IAANS covalently coupled to Cys84 of wild-type cTnC is sensitive to conformational change caused by Ca2+ binding to the regulatory site II; the present study also utilizes the C35S mutant, in which Cys84 is the lone cysteine, to ensure the specificity of IAANS labeling. Site II Ca2+ affinities for cTnC-wt, cTnC-C35S, cTnC-wt-IAANS2, and cTnC-C35S-IAANS were similar (KD = 2-5 microM at 25 degrees C; KD = 2-8 microM at 4 degrees C), indicating that neither the IAANS label nor the C35S mutation strongly perturbs site II Ca2+ affinity. To directly determine the rate of Ca2+ dissociation from site II, the Ca2+-loaded protein was rapidly mixed with a spectroscopically sensitive chelator in a stopped flow spectrometer. The resulting site II Ca2+ off-rates were k(off) = 700-800 s(-1) (4 degrees C) for both cTnC-wt and cTnC-C35S, yielding calculated macroscopic site II Ca2+ on-rates of k(on) = k(off)/KD = 2-4 x 10(8) M(-1) s(-1) (4 degrees C). As observed for Ca2+ affinities, neither the C35S mutation nor IAANS labeling significantly altered the Ca2+ on- and off-rates. Using IAANS fluorescence as a monitor of the protein conformational state, the intramolecular conformational changes (delta) induced by Ca2+ binding and release at site II were found to be significantly slower than the Ca2+ on- and off-rates. The conformational rate constants measured for cTnC-wt-IAANS2 and cTnC-C35S-IAANS were k(delta on) = 120-210 s(-1) and k(delta off) = 90-260 s(-1) (4 degrees C) . Both conformational events were slowed in cTnC-wt-IAANS2 relative to cTnC-C35S-IAANS, presumably due to the bulky IAANS probe coupled to Cys35. Together, the results provide a nearly complete kinetic description of the Ca2+ activation cycle of isolated cTnC, revealing rapid Ca2+ binding and release at site II accompanied by slow conformational steps that are likely to be retained by the full troponin complex during heart muscle contraction and relaxation.

Genetic and morphological findings in progressive familial intrahepatic cholestasis (Byler disease [PFIC-1] and Byler syndrome): evidence for heterogeneity.

Byler disease (ByD) is an autosomal recessive disorder in which cholestasis of onset in infancy leads to hepatic fibrosis and death. Children who have a clinically similar disorder, but are not members of the Amish kindred in which ByD was described, are said to have Byler syndrome (ByS). Controversy exists as to whether ByD and ByS (subtypes of progressive familial intrahepatic cholestasis [PFIC]) represent one clinicopathological entity. The gene for ByD has been mapped to a 19-cM region of 18q21-q22. PFIC caused by a lesion in this region, including ByD, can be designated PFIC-1. Examination of haplotypes in siblings with ByS in two unrelated non-Amish families showed that the gene(s) responsible for their disorder(s) did not lie in the PFIC-1 candidate region. On light microscopy and transmission electron microscopy (TEM), liver tissue differed between Amish children with PFIC-1, who had coarsely granular bile and at presentation had bland intracanalicular cholestasis, and the children with ByS in the two non-Amish families, who had amorphous or finely filamentous bile and at presentation had neonatal hepatitis. Bile acid composition of bile also differed: In the Amish children with PFIC-1 and in one ByS family, the proportional concentration of chenodeoxycholic acid (CDCA) in bile was low compared with normal bile; in the other ByS family, it was only slightly reduced. Genetic analysis and light microscopy and TEM of liver may help distinguish PFIC-1 from other forms of ByS.

PDZ domain of neuronal nitric oxide synthase recognizes novel C-terminal peptide sequences.

PDZ domains are multifunctional protein-interaction motifs that often bind to the C-terminus of protein targets. Nitric oxide (NO), an endogenous signaling molecule, plays critical roles in nervous, immune, and cardiovascular function. Although there are numerous physiological functions for neuron-derived NO, produced primarily by the neuronal NO synthase (nNOS), excess nNOS activity mediates brain injury in cerebral ischemia and in animal models of Parkinson's disease. Subcellular localization of nNOS activity must therefore be tightly regulated. To determine ligands for the PDZ domain of nNOS, we screened 13 billion distinct peptides and found that the nNOS-PDZ domain binds tightly to peptides ending Asp-X-Val. This differs from the only known (Thr/Ser)-X-Val consensus that interacts with PDZ domains from PSD-95. Preference for Asp at the -2 peptide position is mediated by Tyr-77 of nNOS. A Y77D78 to H77E78 substitution changes the binding specificity from Asp-X-Val to Thr-X-Val. Guided by the Asp-X-Val consensus, candidate nNOS interacting proteins have been identified including glutamate and melatonin receptors. Our results demonstrate that PDZ domains have distinct peptide binding specificity.

Biocompatibility of ferric calcium phosphorous oxide ceramics.

The objective of this investigation was to ascertain the biocompatability of a ferric calcium phosphorous oxide ceramic (FECAP). The FECAP ceramic was fabricated from stock powders combined in a ratio of 46:40:14 by weight of Fe2O3:CaO:P2O5. The composite oxides were mixed for homogeneity, pressed into a 20g block, and calcined in a crucible at 1100 degrees C for 12 hours. The calcined ceramic was then ground in a ball mill before separation into particle sizes of 38-45 microns and 63-75 microns, by an automatic siever and shaker. Calcined powders of each particle size were mixed with polyvinyl alcohol binder (0.025g PVA/1.0g of FECAP), and pressed into 0.5g pellets in a 5/16" (internal diameter) die at a 1820 kilogram load using a Carver hydraulic press. FECAP pellets were then sintered at 1100 degrees C for 12 hours. For this investigation, sixty albino (Sprague-Dawley) rats weighing 125-425 g each, were distributed into four groups: non-operated controls, sham-operated controls, and two groups subcutaneously implanted with ceramics 38-45 microns and 63-75 microns FECAP ceramics, respectively. Three rats from each group were sacrificed at three, five, seven, and twenty-one days post-surgery. Morphologic examination of the implant and implant site as well as hematocrit data indicate that this ferric-calcium-phosphorous oxide ceramic is biocompatible. Data obtained todate suggest that sintered FECAP should have a wide variety of dental and medical applications, especially where iron deficiency is a concern.