Effects of gonadal steroids on reward circuitry function and anhedonia in women with a history of postpartum depression

BACKGROUND

Reward system dysfunction is evident across neuropsychiatric conditions. Here we present data from a double-blinded pharmaco-fMRI study investigating the triggering of anhedonia and reward circuit activity in women.

METHODS

The hormonal states of pregnancy and parturition were simulated in euthymic women with a history of postpartum depression (PPD+; n = 15) and those without such a history (PPD-; n = 15) by inducing hypogonadism, adding back estradiol and progesterone for 8 weeks ("addback"), and then withdrawing both steroids ("withdrawal"). Anhedonia was assessed using the Inventory of Depression and Anxiety Symptoms (IDAS) during each hormone phase. Those who reported a 30 % or greater increase in IDAS anhedonia, dysphoria, or ill temper during addback or withdrawal, compared with pre-treatment, were identified as hormone sensitive (HS+) and all others were identified as non-hormone sensitive (HS-). The monetary incentive delay (MID) task was administered during fMRI sessions at pre-treatment and during hormone withdrawal to assess brain activation during reward anticipation and feedback.

RESULTS

On average, anhedonia increased during addback and withdrawal in PPD+ but not PPD-. During reward feedback, both HS+ (n = 10) and HS- (n = 18) showed decreased activation in clusters in the right putamen (p < .031, FWE-corrected) and left postcentral and supramarginal gyri (p < .014, FWE-corrected) at the withdrawal scans, relative to pre-treatment scans.

LIMITATIONS

A modest sample size, stringent exclusion criteria, and relative lack of diversity in study participants limit the generalizability of results.

CONCLUSION

Although results do not explain differential hormone sensitivity in depression, they demonstrate significant effects of reproductive hormones on reward-related brain function in women.

Student Learning Dispositions: Multidimensional Profiles Highlight Important Differences among Undergraduate STEM Honors Thesis Writers

Various personal dimensions of students-particularly motivation, self-efficacy beliefs, and epistemic beliefs-can change in response to teaching, affect student learning, and be conceptualized as learning dispositions. We propose that these learning dispositions serve as learning outcomes in their own right; that patterns of interrelationships among these specific learning dispositions are likely; and that differing constellations (or learning disposition profiles) may have meaningful implications for instructional practices. In this observational study, we examine changes in these learning dispositions in the context of six courses at four institutions designed to scaffold undergraduate thesis writing and promote students' scientific reasoning in writing in science, technology, engineering, and mathematics. We explore the utility of cluster analysis for generating meaningful learning disposition profiles and building a more sophisticated understanding of students as complex, multidimensional learners. For example, while students' self-efficacy beliefs about writing and science increased across capstone writing courses on average, there was considerable variability at the level of individual students. When responses on all of the personal dimensions were analyzed jointly using cluster analysis, several distinct and meaningful learning disposition profiles emerged. We explore these profiles in this work and discuss the implications of this framework for describing developmental trajectories of students' scientific identities.

Shope fibroma virus RING finger protein N1R binds DNA and inhibits apoptosis

Shope fibroma virus (SFV) N1R gene encodes a RING finger protein that localizes to virus factories within the cytoplasm of infected cells. Altered proteins, with deletions and site-specific mutations, were transiently expressed in vaccinia virus-infected cells to discern regions of the protein that are required for localization. We have determined that at least part of the RING finger region is necessary for localization but that the RING motif alone is not sufficient. A chimeric protein, however, in which the RING finger region of the herpes simplex virus-1 ICP0 protein replaces the SFV N1R RING motif does localize to virus factories. A region of five highly conserved amino acids at the amino terminus of SFV N1R is also critical for localization. We report that the SFV N1R protein binds double- and single-stranded DNA, suggesting a mechanism for localization, and that overexpression of this protein in vaccinia virus-infected cells reduces apoptosis-associated fragmentation of nuclear DNA.

Preferential translation of reovirus mRNA by a sigma3-dependent mechanism

We have characterized reovirus strains that differ in the degree to which they inhibit cellular protein synthesis and used them to investigate mechanisms regulating gene expression in infected cells. A previous genetic study associated distinct effects of reovirus strains on cellular translation with polymorphisms in viral protein sigma3. In cell extracts, sigma3 sequesters double-stranded RNA (dsRNA) and blocks activation of the dsRNA-activated protein kinase (PKR), an interferon-induced enzyme that inhibits translational initiation by phosphorylating elF-2alpha. We found that in infected cells, cellular protein synthesis is translationally regulated in a strain-specific manner. Using immunoprecipitation and indirect immunofluorescence we showed that the effect of a strain on cellular translation is not determined by the level of sigma3, but appears to result from differences in sigma3 localization. In cells infected with a strain that spares cellular translation, sigma3 is present throughout the cytoplasm, whereas in cells infected with inhibitory strains, sigma3 is restricted to perinuclear viral factories. Biochemical studies suggested that diffuse localization of sigma3 is a consequence of low affinity for capsid protein mu1. Our findings are consistent with a model in which the efficiency of cellular translation is determined by the cytoplasmic level of sigma3 that is not complexed with mu1.

Comparative sequence analysis of the reovirus S4 genes from 13 serotype 1 and serotype 3 field isolates

The reovirus sigma 3 protein is a major outer capsid protein that may function to regulate translation within infected cells. To facilitate the understanding of sigma 3 structure and functions and the evolution of mammalian reoviruses, we sequenced cDNA copies of the S4 genes from 10 serotype 3 and 3 serotype 1 reovirus field isolates and compared these sequences with sequences of prototypic strains of the three reovirus serotypes. We found that the sigma 3 proteins are highly conserved: the two longest conserved regions contain motifs proposed to function in binding zinc and double-stranded RNA. We used the 16 viral isolates to investigate the hypothesis that structural interactions between sigma 3 and the cell attachment protein, sigma 1, constrain their evolution and to identify a determinant within sigma 3 that is in close proximity to the sigma 1 hemagglutination site.

A poxvirus protein with a RING finger motif binds zinc and localizes in virus factories

Shope fibroma virus (SFV) is a Leporipoxvirus closely related to the highly virulent myxoma virus. The DNA sequence of the BamHI N fragment of the SFV DNA genome was determined, and the single complete open reading frame (N1R) was characterized. The protein encoded by the N1R gene was found to contain a C3HC4 RING finger motif at the C terminus. This C3HC4 motif is the hallmark of a growing family of proteins, many of which are involved in regulation of gene expression, DNA repair, or DNA recombination. Complete homologs of the SFV N1R gene were also detected in variola virus, myxoma virus, and vaccinia virus strain IHD-W. In contrast, the gene is completely absent from vaccinia virus strain Copenhagen, and in vaccinia virus strain WR, the open reading frame is truncated prior to the zinc binding domain because of an 11-bp deletion, thus producing a frameshift and premature stop codon. Recombinant N1R protein from SFV was expressed in Escherichia coli and shown to bind zinc in a specific manner. Using fluorescence microscopy to visualize a peptide epitope tag (derived from ICP27 of herpes simplex virus) fused to the N terminus of the poxvirus proteins, we observed that the N1R protein of SFV and its homologs in myxoma virus and vaccinia virus IHD-W were localized primarily to the virus factories in the cytoplasm of infected cells and, to a lesser degree, the host cell nucleus. The truncated protein of vaccinia virus strain WR failed to localize in this manner but instead was observed throughout the cytoplasm.

How to start a direct patient care team

Many American hospitals are embracing the philosophies of continuous quality improvement (CQI) or total quality management (TQM). To date, case studies in the literature have largely dealt with administrative processes. However, CQI can also improve direct patient care (clinical) processes using direct patient care teams. The establishment of such teams has been an elusive task at many organizations, largely because of the traditional paradigm of the appropriate relationship between provider and patient. However, similarities between direct patient care teams and other cross-functional teams far exceed differences. Using case studies from two teams (HIV and chest pain) at HCA West Paces Ferry Hospital and Southeastern Health Services, this article suggests ways facilitators can help providers examine, redesign, and improve direct patient care processes.

Quality improvement: an imperative for medical care

For continuous process improvement to be successful at the site of care, an organizational structure for quality improvement should be in place. Quality improvement requires (1) an environment for quality improvement and (2) tools for improvement, including statistical and meeting tools. Physicians and all other care givers and support personnel must cooperate for process knowledge to be complete and usable. Perhaps there is no such thing as a purely "clinical" system, because the contiguous systems influence clinical behavior so completely they are almost inseparable. Process improvement specifications are not the same thing as standards as we now understand them. Process improvement specification are process based. They expect, are designed for, and handle divergent pathophysiologic conditions by focusing on processes. Individual institutions define and measure their outputs, but these outputs are judged against their customers' needs and expectations (thereby becoming outcomes) for performance, features, reliability, conformance, durability, serviceability, aesthetics, and perceived quality. Outcomes research as known today can help us understand the needs and expectations of our customers. Moreover, any team can improve the framework of quality improvement.

Neuronal organization of fetal striatal grafts in kainate- and sham-lesioned rat caudate nucleus: light- and electron-microscopic observations

Behavioral and biochemical studies have suggested that fetal striatal grafts in the adult rat neostriatum can reverse deficits induced by excitotoxic lesions of the host caudate tissue. In this study, fetal day 17-18 striatal grafts were examined at 2, 5-6, 12, and 44-48 weeks following their implantation into saline- or kainic acid-treated host caudate nucleus in order to compare the neuronal organization of the grafts and the host caudate nucleus and to determine whether the differentiation of graft tissue was influenced by the period of implantation or prior lesion of the host caudate nucleus with kainic acid. Compared to host neostriatum, the grafts at the light-microscopic level lacked bundles of myelinated axons and had neurons that were tightly packed in clusters and rich in Nissl substance. Neurons in the grafts were mostly of medium size, had significantly larger cross-sectional areas, and more frequently exhibited indented nuclei than host caudate neurons. At the electron-microscopic level, grafts 2 weeks following implantation contained many features seen in the normally developing neostriatum, such as growth cones, immature synapses, and degenerating profiles. Grafts appeared mature by 5-6 weeks and contained at least 6 types of neurons and 8 types of axon terminals, which formed synapses with cell bodies, dendrites, spines, and axon initial segments. Both symmetric and asymmetric synapses were found within the grafts. The density of synapses was significantly lower in all the transplants than in host tissue, with the exception of the 5-6 week grafts, where values were statistically comparable to host caudate. A significantly higher proportion of axodendritic synapses was present in the graft neuropil than in the caudate nucleus. The lengths of the synaptic junctions in the grafts were the same as those in the neostriatum. There was little qualitative or quantitative difference in synaptic organization between transplants in kainic acid and sham-lesioned host, with grafts in both host treatment conditions exhibiting the same synaptic density and proportion of axodendritic/axospinous synapses. The development of a high differentiated ultrastructure within striatal grafts is consistent with recent anatomical evidence showing interconnections between striatal grafts and host-lesioned caudate nucleus. Although graft neuropil shows striking similarities in neuronal organization to the caudate nucleus, it also exhibits some distinct differences that may have implications for understanding the functional properties of fetal striatal grafts in animal models of Huntington's disease.

Jaundice. Clinical pearls and perils revisited

I recount some clinical "pearls and perils" to help reassess the contributions of abdominal ultrasound, cholangiography, needle biopsy of the liver, and laparoscopy. Abdominal ultrasound demonstrates stones in the gallbladder in approximately 98% of cases, but in only 15% in the common bile duct, whereas computerized tomography scan reveals them in greater than or equal to 50%. On cholangiography a blood clot (in hemobilia) may closely resemble a common duct stone, as may spasm or tumor of the distal duct. Iatrogenic stricture at the junction of the left and right hepatic ducts may be indistinguishable from a Klatskin tumor. Differentiation of extrahepatic from intrahepatic cholestasis is frequently impossible in needle specimens of the liver. Needle biopsy provides the best means of establishing a diagnosis of alcoholic hepatitis. Laparoscopy is particularly valuable in the diagnosis of cirrhosis missed in blind biopsy specimens.

Cytochrome oxidase activity in the rat caudate nucleus: light and electron microscopic observations

Cytochrome oxidase (CO) activity was examined in the neostriatum of normal adult rats at the light and electron microscopic level. At the light microscopic level a heterogeneous distribution of CO activity was observed and was characterized by patches of high activity ranging in size from 200 to 800 microns surrounded or adjacent to regions of lower activity. The most dorsomedial and ventromedial regions of the caudate nucleus appeared to be consistently high in activity in all animals. At the ultrastructural level CO reaction product was localized to the membranes and intracristal spaces of mitochondria. The most reactive mitochondria (those containing the denest precipitates of reaction product) were found within the dendrites of spiny neurons in all caudate regions. In areas of high CO activity the mitochondria within bundles of myelinated fibers and in many axon terminals were also highly reactive whereas those in neuronal somata, primary dendrites, and glial cells and processes exhibited relatively little activity. Quantitative study showed that mitochondria within dendrites accounted for most of the CO activity in caudate neuropil. The mitochondria within dendrites and axon terminals were more reactive in regions of high CO activity than in regions of low CO activity. No differences in the density of synapses or in the proportions of axospinous and axodendritic synapses were observed between CO-rich and CO-poor areas. Heterogeneity in the distribution of CO activity in the caudate nucleus may be related to the "patchy" pattern of localization previously observed for some neostriatal afferents, enzymes, transmitters, peptides, and receptor ligands.(ABSTRACT TRUNCATED AT 250 WORDS)

Prolonged intrahepatic cholestasis secondary to acute hepatitis A

Viral hepatitis characterized by prolonged cholestasis has not been associated with a specific serologic marker. We report the cases of six patients presenting with a clinical syndrome typical of cholestatic hepatitis who were subsequently found to have acute hepatitis A. Usual features include pruritus, fever, diarrhea, and weight loss with serum bilirubin levels greater than 10 mg/dL, and a clinical course lasting at least 12 weeks. All patients recovered completely without sequelae. Knowledge of this unusual manifestation of hepatitis A may help avoid potentially invasive procedures involved in the evaluation of suspected obstructive jaundice and facilitate appropriate immunoprophylactic measures.