Optimizing Human Synovial Fluid Preparation for Two-Dimensional Gel Electrophoresis

Background

Prenatal screening for Down Syndrome (DS) would benefit from an increased number of biomarkers to improve sensitivity and specificity. Improving sensitivity and specificity would decrease the need for potentially risky invasive diagnostic procedures.

Results

We have performed an in depth two-dimensional difference gel electrophoresis (2D DIGE) study to identify potential biomarkers. We have used maternal plasma samples obtained from first and second trimesters from mothers carrying DS affected fetuses compared with mothers carrying normal fetuses. Plasma samples were albumin/IgG depleted and expanded pH ranges of pH 4.5 - 5.5, pH 5.3 - 6.5 and pH 6 - 9 were used for two-dimensional gel electrophoresis (2DE). We found no differentially expressed proteins in the first trimester between the two groups. Significant up-regulation of ceruloplasmin, inter-alpha-trypsin inhibitor heavy chain H4, complement proteins C1s subcomponent, C4-A, C5, and C9 and kininogen 1 were detected in the second trimester in maternal plasma samples where a DS affected fetus was being carried. However, ceruloplasmin could not be confirmed as being consistently up-regulated in DS affected pregnancies by Western blotting.

Conclusions

Despite the in depth 2DE approach used in this study the results underline the deficiencies of gel-based proteomics for detection of plasma biomarkers. Gel-free approaches may be more productive to increase the number of plasma biomarkers for DS for non-invasive prenatal screening and diagnosis.     

Differences in Elasticity of Vinculin-Deficient F9 Cells Measured by Magnetometry and Atomic Force Microscopy

We have investigated a mouse F9 embryonic carcinoma cell line, in which both vinculin genes were inactivated by homologous recombination, that exhibits defective adhesion and spreading [Collet al.(1995)Proc. Natl. Acad. Sci. USA92, 9161–9165]. Using a magnetometer and RGD-coated magnetic microbeads, we measured the local effect of loss and replacement of vinculin on mechanical force transfer across integrins. Vinculin-deficient F9Vin(−/−) cells showed a 21% difference in relative stiffness compared to wild-type cells. This was restored to near wild-type levels after transfection and constitutive expression of increasing amounts of vinculin into F9Vin(−/−) cells. In contrast, the transfection of vinculin constructs deficient in amino acids 1–288 (containing the talin- and α-actinin-binding site) or substituting tyrosine for phenylalanine (phosphorylation site, amino acid 822) in F9Vin(−/−) cells resulted in partial restoration of stiffness. Using atomic force microscopy to map the relative elasticity of entire F9 cells by 128 × 128 (n= 16,384) force scans, we observed a correlation with magnetometer measurements. These findings suggest that vinculin may promote cell adhesion and spreading by stabilizing focal adhesions and transferring mechanical stresses that drive cytoskeletal remodeling, thereby affecting the elastic properties of the cell.     

Human megakaryocytic progenitors (CFU-M) assayed in methylcellulose: Physical characteristics and requirements for growth

The basic culture requirements and several physical characteristics were defined for megakaryocytic colony-forming cells (CFU-M) from normal human marrow growing in methylcellulose. Ficoll-hypaque separated mononuclear cells from human, marrow gave rise to megakaryocytic colonies in the presence of normal human plasma and phytohemagglutinin-stimulated leukocyte-conditioned medium (PHA-LCM). Their identity as megakaryocytic colonies was confirmed by immunofluorescence staining with a monoclonal antibody to human factor VIII antigen and by electron microscopy of individually harvested colonies. Demonstration of the single-cell origin of the colonies was provided by analysis of the glucose-6-phosphate dehydrogenase (G-6-PD) enzyme type of individually harvested colonies grown from a G-6-PD heterozygote. The colonies grew best in heparinized or citrated plasma as opposed to serum. Detailed studies suggested that platelet-release products were responsible for this difference. Tritiated thymidine suicide studies showed that the percentage of CFU-M in DNA synthesis was 23 ± 8% (n = 10). The modal velocity sedimentation rate of CFU-M was 4.9 ± 0.6 mm/hr (n = 4) while that of concurrently studied granulocyte/macrophage colony-forming cells (CFU-GM) was 5.7 ± 0.5 mm/hr. Examination of the PHA-LCM dose-response characteristics suggested the presence in the conditioned medium of an inhibitor to megakaryocyte colony growth which was partially removed by chromatography of the medium on Sephadex G-100. The resulting conditioned medium increased the cloning efficiency for CFU-M compared with that with crude PHA-LCM (15.3 ± 7.0 and 8.2 ± 5.3/10⁵ marrow cells, respectively).     

The Effect of an Individualized Practice-Based CME Program on Physician Performance and Patient Outcomes

The Professional Competence Assurance Program (PROCAP) is an individualized educational program that examines physicians'' performance in ambulatory practice. It uses medical record review to identify deficiencies in the care process that guides development of the educational intervention. Medical care is reassessed one year later. This program was used with 51 private practitioners to assess the care of 1,229 hypertensive patients. The educational program included a computer printout comparing one physician''s performance with that of peers, readings targeted to management problems, and a conference call or group seminar with an expert stressing issues relevant to each physician''s performance. Postintervention assessment showed that physicians prescribed beta-blockers (P<.01) and vasodilators (P<.01) more often. Improvement (P<.05) occurred in the control of diastolic blood pressure (≤90 mm of mercury) and in several other criteria. These results show that well-designed, individualized continuing medical education addressing specific deficiencies can change physicians'' performance and patients'' intermediate outcome.     

Diagnostic accuracy of case-finding questions to identify perinatal depression

Background:

Guidelines for perinatal mental health care recommend the use of two case-finding questions about depressed feelings and loss of interest in activities, despite the absence of validation studies in this context. We examined the diagnostic accuracy of these questions and of a third question about the need for help asked of women receiving perinatal care.

Methods:

We evaluated self-reported responses to two case-finding questions against an interviewer-assessed diagnostic standard (DSM-IV criteria for major depressive disorder) among 152 women receiving antenatal care at 26–28 weeks’ gestation and postnatal care at 5–13 weeks after delivery. Among women who answered “yes” to either question, we assessed the usefulness of asking a third question about the need for help. We calculated sensitivity, specificity and likelihood ratios for the two case-finding questions and for the added question about the need for help.

Results:

Antenatally, the two case-finding questions had a sensitivity of 100% (95% confidence interval [CI] 77%–100%), a specificity of 68% (95% CI 58%–76%), a positive likelihood ratio of 3.03 (95% CI 2.28–4.02) and a negative likelihood ratio of 0.041 (95% CI 0.003–0.63) in identifying perinatal depression. Postnatal results were similar. Among the women who screened positive antenatally, the additional question about the need for help had a sensitivity of 58% (95% CI 38%–76%), a specificity of 91% (95% CI 78%–97%), a positive likelihood ratio of 6.86 (95% CI 2.16–21.7) and a negative likelihood ratio of 0.45 (95% CI 0.25–0.80), with lower sensitivity and higher specificity postnatally.

Interpretation:

Negative responses to both of the case-finding questions showed acceptable accuracy for ruling out perinatal depression. For positive responses, the use of a third question about the need for help improved specificity and the ability to rule in depression.The occurrence of depressive symptoms during the perinatal period is well-recognized. The estimated prevalence is 7.4%–20% antenatally^1,2 and up to 19.2% in the first three postnatal months.³ Antenatal depression is associated with malnutrition, substance and alcohol abuse, poor self-reported health, poor use of antenatal care services and adverse neonatal outcomes.⁴ Postnatal depression has a substantial impact on the mother and her partner, the family, mother–baby interaction and on the longer-term emotional and cognitive development of the baby.⁵Screening strategies to identify perinatal depression have been advocated, and specific questionnaires for use in the perinatal period, such as the Edinburgh Postnatal Depression Scale,⁶ were developed. However, in their current recommendations, the UK National Screening Committee⁷ and the US Committee on Obstetric Practice⁸ state that there is insufficient evidence to support the implementation of universal perinatal screening programs. The initial decision in 2001 by the National Screening Committee to not support universal perinatal screening⁹ attracted particular controversy in the United Kingdom; some service providers subsequently withdrew resources for treatment of postnatal depression, and subsequent pressure by perinatal community practitioners led to modification of the screening guidance in order to clarify the role of screening questionnaires in the assessment of perinatal depression.¹⁰In 2007, the National Institute for Health and Clinical Excellence issued clinical guidelines for perinatal mental health care in the UK, which included guidance on the use of questionnaires to identify antenatal and postnatal depression.¹¹ In this guidance, a case-finding approach to identify perinatal depression was strongly recommended; it involved the use of two case-finding questions (sometimes referred to as the Whooley questions), and an additional question about the need for help asked of women who answered “yes” to either of the initial questions (Box 1).

Box 1:

Case-finding questions recommended for the identification of perinatal depression¹⁰

• “During the past month, have you often been bothered by feeling down, depressed or hopeless?”
• “During the past month, have you often been bothered by having little interest or pleasure in doing things?”
• A third question should be considered if the woman answers “yes” to either of the initial screening questions: “Is this something you feel you need or want help with?”

Useful case-finding questions should be both sensitive and specific so they accurately identify those with and without the condition. The two case-finding questions have been validated in primary care samples^12,13 and examined in other clinical populations^14–16 and are endorsed in recommendations by US and Canadian bodies for screening depression in adults.^17,18 However, at the time the guidance from the National Institute for Health and Clinical Excellence was issued, there were no validation studies conducted in perinatal populations. A recent systematic review¹⁹ identified one study conducted in the United States that validated the two questions against established diagnostic criteria in 506 women attending well-child visits postnatally;²⁰ sensitivity and specificity of the questions were 100% and 44% respectively at four weeks. The review failed to identify studies that validated the two questions and the additional question about the need for help against a gold-standard measure.We conducted a validation study to assess the diagnostic accuracy of this brief case-finding approach against gold-standard psychiatric diagnostic criteria for depression in a population of women receiving perinatal care.     

Identification of a novel risk locus for progressive supranuclear palsy by a pooled genomewide scan of 500,288 single-nucleotide polymorphisms

To date, only the H1 MAPT haplotype has been consistently associated with risk of developing the neurodegenerative disease progressive supranuclear palsy (PSP). We hypothesized that additional genetic loci may be involved in conferring risk of PSP that could be identified through a pooling-based genomewide association study of >500,000 SNPs. Candidate SNPs with large differences in allelic frequency were identified by ranking all SNPs by their probe-intensity difference between cohorts. The MAPT H1 haplotype was strongly detected by this methodology, as was a second major locus on chromosome 11p12-p11 that showed evidence of association at allelic (P<.001), genotypic (P<.001), and haplotypic (P<.001) levels and was narrowed to a single haplotype block containing the DNA damage-binding protein 2 (DDB2) and lysosomal acid phosphatase 2 (ACP2) genes. Since DNA damage and lysosomal dysfunction have been implicated in aging and neurodegenerative processes, both genes are viable candidates for conferring risk of disease.     

Molecular evolution of P transposable elements in the genus Drosophila. III. The melanogaster species group

Phylogenetic relationships were determined for 76 partial P-element sequences from 14 species of the melanogaster species group within the Drosophila subgenus Sophophora. These results are examined in the context of the phylogeny of the species from which the sequences were isolated. Sequences from the P-element family fall into distinct subfamilies, or clades, which are often characteristic for particular species subgroups. When examined locally among closely related species, the evolution of P elements is characterized by vertical transmission, whereby the P-element phylogeny traces the species phylogeny. On a broader scale, however, the P-element phylogeny is not congruent with the species phylogeny. One feature of P-element evolution in the melanogaster group is the presence of more than one P-element subfamily, differing by as much as 36%, in the genomes of some species. Thus, P elements from several individual species are not monophyletic, and a likely explanation for the incongruence between P-element and species phylogenies is provided by the comparison of paralogous sequences. In certain instances, horizontal transfer seems to be a valid alternative explanation for lack of congruence between species and P-element phylogenies. The canonical P-element subfamily, which represents the active, autonomous transposable element, is restricted to D. melanogaster. Thus, its origin clearly lies outside of the melanogaster species group, consistent with the earlier conclusion of recent horizontal transfer.