Torsion of an accessory spleen

Torsion of an accessory spleen is extremely rare. We report a case of an acute torsion of an accessory spleen in a young patient who presented with acute left abdominal pain and discuss the computed tomographic findings of this exceptional condition. Awareness of this entity and familiarity with typical imaging findings are mandatory for preoperative diagnosis.

Still looking for Poppa

In 1992, V. Phares published an article titled "Where's Poppa?: The Relative Lack of Attention to the Role of Fathers in Child and Adolescent Psychopathology". Since that time, there have been modest gains in the research literature on clinical child issues, but there remains a wide gap between the inclusion of mothers and fathers in clinical child and family research. To provide an update of this issue for the field of developmental psychopathology, the authors of this comment conducted an updated review and analysis of the research on fathers and developmental psychopathology. These current data were compared with the data from the Phares and Compas (1992) study. It was found that there continues to be a dearth of research on fathers and developmental psychopathology.

A theoretical model of common process factors in youth and family therapy

Recently there has been an increasing emphasis in the youth and family mental health treatment literature on the use of empirically supported treatments (ESTs). In contrast there has been scant attention paid to more universal aspects of the therapy process that may have even greater impact upon therapy outcomes. It is likely that the success of the techniques proposed by ESTs may depend on the presence of common process factors. In this article, the authors explore the status of common process factors research in the youth and family therapy literature, and propose a theoretical model linking specific therapeutic relationship variables and treatment outcomes for children and adolescents. This model is intended to guide synthesis of the empirical evidence for common process factors in youth and family treatment and to stimulate future research on common process factors.

Are fathers involved in pediatric psychology research and treatment?

BACKGROUND

Recently, there has been a growing awareness of the importance of the roles of fathers in understanding normative developmental processes. Increased attention has been given to the roles of fathers in the area of clinical child research and therapy. However, the presence of fathers in research and treatment in pediatric psychology has not been fully examined.

OBJECTIVE

To explore the status of including fathers in both research and treatment in the area of pediatric psychology.

METHOD

An extensive review of published research.

RESULTS

The findings suggest that pediatric psychology research lags even farther behind clinical child research in including fathers in research designs and analyzing for maternal and paternal effects separately. There is also a concomitant lack of inclusion of fathers in family-based interventions in pediatric psychology.

CONCLUSION

These patterns are discussed, with an emphasis on strategies to increase the inclusion of fathers in research and treatment of pediatric psychology issues. Future directions for researchers and clinicians are also included.

Still looking for Poppa

In 1992, V. Phares published an article titled "Where's Poppa?: The Relative Lack of Attention to the Role of Fathers in Child and Adolescent Psychopathology". Since that time, there have been modest gains in the research literature on clinical child issues, but there remains a wide gap between the inclusion of mothers and fathers in clinical child and family research. To provide an update of this issue for the field of developmental psychopathology, the authors of this comment conducted an updated review and analysis of the research on fathers and developmental psychopathology. These current data were compared with the data from the Phares and Compas (1992) study. It was found that there continues to be a dearth of research on fathers and developmental psychopathology.

Computerized Evaluation of Mammographic Lesions:What Diagnostic Role Does the Shape of the Individual Microcalcifications Play Compared with the Geometry of the Cluster?

OBJECTIVE

The objective of this study was to compare the diagnostic role of features reflecting the geometry of clusters with features reflecting the shape of the individual microcalcification in a mammographic computer-aided diagnosis system.

MATERIALS AND METHODS

Three hundred twenty-four cases of clustered microcalcifications with biopsy-proven results were digitized at 42-microm resolution and analyzed on a computerized system. The shape factor and number of neighbors were computed for each microcalcification, and the eccentricity of the cluster was computed as well. The shape factor is related to the individual microcalcification; the average number of neighbors and the cluster eccentricity reflect the cluster geometry. Stepwise discriminant analysis was used to evaluate the contribution of the extracted features in predicting malignancy. The performance of a classifier based on the features selected by stepwise discriminant analysis was evaluated by receiver operating characteristic (ROC) analysis.

RESULTS

To obtain the best discrimination model, we used stepwise discriminant analysis to select the average number of neighbors and the shape of the individual microcalcification, but excluded cluster eccentricity. A classification scheme assigned the average number of neighbors a weighting factor, which was 1.49 times greater than that assigned to the shape factor of the individual microcalcification. A scheme based only on these two features yielded an ROC curve with an area under the curve (A(z)) of 0.87, indicating a positive predictive value of 61% for 98% sensitivity.

CONCLUSION

Computerized analysis permitted calculations reflecting the shape of individual microcalcification and the geometry of clusters of microcalcifications. For the computerized classification scheme studied, the cluster geometry was more effective in differentiating benign from malignant clusters than was the shape of individual microcalcification.

Altered transcription in yeast expressing expanded polyglutamine

Expanded polyglutamine tracts are responsible for at least eight fatal neurodegenerative diseases. In mouse models, proteins with expanded polyglutamine cause transcriptional dysregulation before onset of symptoms, suggesting that this dysregulation may be an early event in polyglutamine pathogenesis. Transcriptional dysregulation and cellular toxicity may be due to interaction between expanded polyglutamine and the histone acetyltransferase CREB-binding protein. To determine whether polyglutamine-mediated transcriptional dysregulation occurs in yeast, we expressed polyglutamine tracts in Saccharomyces cerevisiae. Gene expression profiles were determined for strains expressing either a cytoplasmic or nuclear protein with 23 or 75 glutamines, and these profiles were compared to existing profiles of mutant yeast strains. Transcriptional induction of genes encoding chaperones and heat-shock factors was caused by expression of expanded polyglutamine in either the nucleus or cytoplasm. Transcriptional repression was most prominent in yeast expressing nuclear expanded polyglutamine and was similar to profiles of yeast strains deleted for components of the histone acetyltransferase complex Spt/Ada/Gcn5 acetyltransferase (SAGA). The promoter from one affected gene (PHO84) was repressed by expanded polyglutamine in a reporter gene assay, and this effect was mitigated by the histone deacetylase inhibitor, Trichostatin A. Consistent with an effect on SAGA, nuclear expanded polyglutamine enhanced the toxicity of a deletion in the SAGA component SPT3. Thus, an early component of polyglutamine toxicity, transcriptional dysregulation, is conserved in yeast and is pharmacologically antagonized by a histone deacetylase inhibitor. These results suggest a therapeutic approach for treatment of polyglutamine diseases and provide the potential for yeast-based screens for agents that reverse polyglutamine toxicity.

A yeast sensor of ligand binding

We describe a biosensor that reports the binding of small-molecule ligands to proteins as changes in growth of temperature-sensitive yeast. The yeast strains lack dihydrofolate reductase (DHFR) and are complemented by mouse DHFR containing a ligand-binding domain inserted in a flexible loop. Yeast strains expressing two ligand-binding domain fusions, FKBP12-DHFR and estrogen receptor-alpha (ERalpha)-DHFR, show increased growth in the presence of their corresponding ligands. We used this sensor to identify mutations in residues of ERalpha important for ligand binding, as well as mutations generally affecting protein activity or expression. We also tested the sensor against a chemical array to identify ligands that bind to FKBP12 or ERalpha. The ERalpha sensor was able to discriminate among estrogen analogs, showing different degrees of growth for the analogs that correlated with their relative binding affinities (RBAs). This growth assay provides a simple and inexpensive method to select novel ligands and ligand-binding domains.

Two-hybrid analysis of the Saccharomyces cerevisiae 26S proteasome

A two-hybrid screen against an activation domain array of Saccharomyces cerevisiae proteins was carried out for 31 yeast proteasome proteins. Fifty-five putative interactions were identified: 21 between components of the proteasome complex and 34 between proteasome proteins and other proteins. Many of these latter interactions involved either proteins of the ubiquitin pathway, cell cycle proteins, protein kinases or a translation initiation factor subunit. The role of eleven proteins associated with proteasome function by these screens was analyzed by examining the corresponding deletion strains for temperature sensitivity and canavanine sensitivity and for the stability of a ubiquitin-beta-galactosidase fusion protein. These assays additionally implicated three proteins, Bim1, Ump1, and YKL171W, in proteasome function. This study demonstrates the utility of genome-wide two-hybrid assays as an entry point for the further analysis of a large protein complex.

The interplay of biology and technology

Technologies for biological research arise in multiple ways-through serendipity, through inspired insights, and through incremental advances-and they are tightly coupled to progress in engineering. Underlying the complex dynamics of technology and biology are the different motivations of those who work in the two realms. Consideration of how methodologies emerge has implications for the planning of interdisciplinary centers and the training of the next generation of scientists.

A protein interaction map for cell polarity development

Many genes required for cell polarity development in budding yeast have been identified and arranged into a functional hierarchy. Core elements of the hierarchy are widely conserved, underlying cell polarity development in diverse eukaryotes. To enumerate more fully the protein-protein interactions that mediate cell polarity development, and to uncover novel mechanisms that coordinate the numerous events involved, we carried out a large-scale two-hybrid experiment. 68 Gal4 DNA binding domain fusions of yeast proteins associated with the actin cytoskeleton, septins, the secretory apparatus, and Rho-type GTPases were used to screen an array of yeast transformants that express approximately 90% of the predicted Saccharomyces cerevisiae open reading frames as Gal4 activation domain fusions. 191 protein-protein interactions were detected, of which 128 had not been described previously. 44 interactions implicated 20 previously uncharacterized proteins in cell polarity development. Further insights into possible roles of 13 of these proteins were revealed by their multiple two-hybrid interactions and by subcellular localization. Included in the interaction network were associations of Cdc42 and Rho1 pathways with proteins involved in exocytosis, septin organization, actin assembly, microtubule organization, autophagy, cytokinesis, and cell wall synthesis. Other interactions suggested direct connections between Rho1- and Cdc42-regulated pathways; the secretory apparatus and regulators of polarity establishment; actin assembly and the morphogenesis checkpoint; and the exocytic and endocytic machinery. In total, a network of interactions that provide an integrated response of signaling proteins, the cytoskeleton, and organelles to the spatial cues that direct polarity development was revealed.

Oral clearance and pathogenic oropharyngeal colonization in the elderly

The elderly have an increased incidence of oropharyngeal colonization with respiratory pathogens, a well-known risk factor for the development of pneumonia. Changes in the oral milieu may occur secondary to decreased salivary production and abnormalities in swallowing. These abnormalities, common in the elderly, may result in impaired clearance of organisms, allowing pathogenic colonization. To test this hypothesis, we performed a prospective cross-sectional analysis of 75 elderly institutionalized patients and measured oral clearance using (99m)Tc-human serum albumin (HSA) administered to the oropharynx. Oropharyngeal cultures, salivary cell populations, elastase activity, and clinical parameters were measured simultaneously. Retention of radiolabel ranged from 100% to 2.3% over 120 min of observation. Clearance in the oropharynx was significantly decreased in those patients who had oropharyngeal colonization with gram-negative bacilli (GNB), Staphylococcus aureus (SA), or yeast compared with those demonstrating normal flora by 95% confidence intervals. Decreased clearance was also seen in patients on antidepressants by 95% confidence levels. The absolute number of salivary lymphocytes/ml and buccal cells/ml was increased in colonized patients versus noncolonized persons (mean +/- SEM, 128 x 10(3) +/- 49 x 10(3), 25.4 +/- 11.6 x 10(3)). Elastase activity was elevated in patients who had GNB compared with patients without GNB (mean +/- SEM, 10.6 nM +/- 5.7, versus 2.2 nM +/- 1.2, p = 0.036). We conclude that a decrease in salivary clearance of potentially pathogenic organisms may be a major risk factor for the development of colonization in the elderly.