Breakpoint mapping of 13 large parkin deletions/duplications reveals an exon 4 deletion and an exon 7 duplication as founder mutations

Early-onset Parkinson’s disease (EOPD) has been associated with recessive mutations in parkin (PARK2). About half of the mutations found in parkin are genomic rearrangements, i.e., large deletions or duplications. Although many different rearrangements have been found in parkin before, the exact breakpoints involving these rearrangements are rarely mapped. In the present study, the exact breakpoints of 13 different parkin deletions/duplications, detected in 13 patients out of a total screened sample of 116 EOPD patients using Multiple Ligation Probe Amplification (MLPA) analysis, were mapped using real time quantitative polymerase chain reaction (PCR), long-range PCR and sequence analysis. Deletion/duplication-specific PCR tests were developed as a rapid and low cost tool to confirm MLPA results and to test family members or patients with similar parkin deletions/duplications. Besides several different deletions, an exon 3 deletion, an exon 4 deletion and an exon 7 duplication were found in multiple families. Haplotype analysis in four families showed that a common haplotype of 1.2 Mb could be distinguished for the exon 7 duplication and a common haplotype of 6.3 Mb for the deletion of exon 4. These findings suggest common founder effects for distinct large rearrangements in parkin

The Sarbanes-Oxley Act and Accounting Quality: A Comprehensive Examination

This paper investigates the impact of the Sarbanes-Oxley (SOX) Act on the quality of financial statement information. Where other papers have only investigated the short-term effects of SOX, this paper takes a longer post-SOX period. A distinction is also made between technology and non-technology based firms. Earnings management, conservatism and value relevance measures were used in order to examine the impact of SOX on accounting quality. A significant increase was found on both the earnings management and value relevance measures, which was persistent over a four-year post-SOX period. On the contrary, a slight increase in conservatism was observed, however these results are not significant. Moreover, the technology based firms score worse on the earnings management measure, thus, the separate investigation between technology and non-technology based firms has revealed interesting information which would otherwise have stayed undetected

The Sarbanes-Oxley Act and accounting quality: a comprehensive examination

This paper investigates the impact of the Sarbanes-Oxley (SOX) Act on the quality of financial statement information. Where other papers have only investigated the short-term effects of SOX, this paper takes a longer post-SOX period. A distinction is also made between technology and non-technology based firms. Earnings management, conservatism and value relevance measures were used in order to examine the impact of SOX on accounting quality. A significant increase was found on both the earnings management and value relevance measures, which was persistent over a four-year post-SOX period. On the contrary, a slight increase in conservatism was observed, however these results are not significant. Moreover, the technology based firms score worse on the earnings management measure, thus, the separate investigation between technology and non-technology based firms has revealed interesting information which would otherwise have stayed undetected

GLYCOPROTEIN HORMONE ALPHA‐SUBUNIT AND PROLACTIN RELEASE BY CULTURED PITUITARY ADENOMA CELLS FROM ACROMEGALIC PATIENTS:CORRELATION WITH GH RELEASE

In‐vitro data of pituitary adenoma cells from 28 acromegalic patients were evaluated. In addition to GH, PRL was produced by 16 adenomas (57%) and alpha‐subunit by 15 adenomas (54%) while there was a significantly higher incidence of tumours producing PRL and alpha‐subunit simultaneously. From 26 pituitary adenomas enough cells were obtained in order to perform secretion studies. Percentage basal hormone release (medium: (medium + intra‐cellular hormone)) ± 100% of GH and alpha‐subunit by 11 adenomas showed a close correlation while such a correlation for GH and PRL was present only in a subgroup of 10 of 13 adenomas. The responses of GH and alpha‐subunit release to 10nM SMS201–995, 10nM bromocriptine, 100nM TRH and 10nM GHRH were closely related in that a response or an absent response of GH release to the four secretagogues was virtually always attended with a response or an absent response respectively of alpha‐subunit release. Such a relationship was less evident with respect to the effects of SMS201–995, bromocriptine, TRH and GHRH on GH and PRL release. We conclude that basal and secretagogue‐induced alpha‐subunit release by cultured pituitary adenoma cells from acromegalic patients closely follows the pattern of GH release while such a relationship for GH and PRL is present only in a subgroup of the adenomas secreting GH and PRL simultaneously.</p

Heterogeneity of pituitary adenoma cell subpopulations from acromegalic patients obtained by Percoll density gradient centrifugation

Pituitary adenoma cells from 6 acromegalic patients were separated on continuous Percoll density gradients according to differences in their density. Two adenomas produced GH only in culture, the other 4 adenomas produced either GH and PRL (one adenoma) or GH and α-subunit (one adenoma) or GH, PRL and α-subunit (2 adenomas). The cell subpopulations obtained by this technique differed in the amount of hormone production per 105 cells: GH release decreased from the low density fractions to the higher density fractions in 5 of 6 adenomas. Intracellular GH levels completely followed this profile. In the mixed GH/α-subunit adenomas the α-subunit profile completely paralleled the GH profile, whereas in the mixed GH/PRL adenomas the PRL profile showed a pattern different from that of GH (and α-subunit). In neither of the adenomas did we find any differences between the subpopulations with respect to the responsiveness of GH, PRL or α-subunit release to GHRH, TRH and the somatostatin analogue SMS 201-995. Conclusions: 1. Within pituitary adenomas from acromegalic patients heterogeneity exists with respect to hormone production per cell. 2. The cell subpopulations obtained by density gradient centrifugation are not different in their responsiveness to SMS 201-995, GHRH or TRH. 3. Because GH and α-subunit release by the fractions from the mixed GH/α-subunit secreting adenomas were completely parallel, further evidence for co-release of GH and α-subunit by the same tumoural cells is provided.</p

Long-term culture of rat mammotrope and somatotrope subpopulations separated on continuous Percoll density gradients:Effects of dopamine, TRH, GHRH and somatostatin

Normal adult female rat mammotrope and somatotrope subpopulations were separated on continuous Percoll density gradients according to differences in their density. Viable cells were recovered in 16 fractions. The cells from each fraction were cultured during 7 days after which period 4-h incubations were performed. rPRL secretion per cell increased towards the higher density fractions. No major difference in TRH, dopamine and somatostatin responsiveness was observed between mammotropes that were recovered in the different gradient fractions. In addition, no differences in somatostatin responsiveness between the somatotrope cells in the different gradient fractions were observed. However, somatotropes that were recovered in the highest density region of the gradient appeared to be more responsive to GHRH than the lower density somatotropes. In the various gradient fractions there were no paradoxical effects of TRH and dopamine on rGH release and of GHRH on rPRL release. Conclusions: 1. In long-term cultures there is no evidence for functionally different subpopulations of mammotropes and somatotropes, separated according to differences in their density, with regard to dopamine and TRH responsiveness and with regard to somatostatin responsiveness, respectively. 2. There is no evidence for a (mammosomatotrope?) subpopulation of cells showing paradoxical responses of PRL or GH release to GHRH and dopamine or TRH, respectively.</p

Immunocytochemical localization of lysosomal acid phosphatase in normal and I-cell fibroblasts

This study represents the first example of immunological localization of lysosomal acid phosphatase. The intracellular localization of lysosomal acid phosphatase was investigated with immunocytochemical methods at the light and electron microscopical level in cultured fibroblasts obtained from normal subjects and from a patient with I-cell disease. Double-labeling studies using fluorescence microscopy showed that acid phosphatase is present in the same organelles as other hydrolases. At the electron microscopic level in control fibroblasts acid phosphatase was found in the rough endoplasmic reticulum, lysosomes, at the plasma membrane, in vesicles just below the plasma membrane and in multivesicular bodies. This localization was comparable with that of other lysosomal enzymes tested (acid alpha-glucosidase, N-acetyl-beta-hexosaminidase, beta-galactosidase). Acid phosphatase labeling was mainly found in association with the lysosomal membrane and with membranous material present within the lysosome. In I-cell fibroblasts the label was present in the same subcellular organelles but always associated with membranous structures. We suggest that the association of acid phosphatase with membranes might explain the normal enzyme activity found in I-cell fibroblasts