Studies of mice with cyclic AMP-dependent protein kinase (PKA) defects reveal the critical role of PKA's catalytic subunits in anxiety.

Cyclic adenosine mono-phosphate-dependent protein kinase (PKA) is critically involved in the regulation of behavioral responses. Previous studies showed that PKA's main regulatory subunit, R1α, is involved in anxiety-like behaviors. The purpose of this study was to determine how the catalytic subunit, Cα, might affect R1α's function and determine its effects on anxiety-related behaviors. The marble bury (MB) and elevated plus maze (EPM) tests were used to assess anxiety-like behavior and the hotplate test to assess nociception in wild type (WT) mouse, a Prkar1a heterozygote (Prkar1a(+/-)) mouse with haploinsufficiency for the regulatory subunit (R1α), a Prkaca heterozygote (Prkaca(+/-)) mouse with haploinsufficiency for the catalytic subunit (Cα), and a double heterozygote mouse (Prkar1a(+/-)/Prkaca(+/-)) with haploinsufficiency for both R1α and Cα. We then examined specific brain nuclei involved in anxiety. Results of MB test showed a genotype effect, with increased anxiety-like behavior in Prkar1a(+/-) and Prkar1a(+/-)/Prkaca(+/-) compared to WT mice. In the EPM, Prkar1a(+/-) spent significantly less time in the open arms, while Prkaca(+/-) and Prkar1a(+/-)/Prkaca(+/-) mice displayed less exploratory behavior compared to WT mice. The loss of one Prkar1a allele was associated with a significant increase in PKA activity in the basolateral (BLA) and central (CeA) amygdala and ventromedial hypothalamus (VMH) in both Prkar1a(+/-) and Prkar1a(+/-)/Prkaca(+/-) mice. Alterations of PKA activity induced by haploinsufficiency of its main regulatory or most important catalytic subunits result in anxiety-like behaviors. The BLA, CeA, and VMH are implicated in mediating these PKA effects in brain.

Mediated Electron Transfer at Vertically Aligned Single-Walled Carbon Nanotube Electrodes During Detection of DNA Hybridization.

Vertically aligned single-walled carbon nanotube (VASWCNT) assemblies are generated on cysteamine and 2-mercaptoethanol (2-ME)-functionalized gold surfaces through amide bond formation between carboxylic groups generated at the end of acid-shortened single-walled carbon nanotubes (SWCNTs) and amine groups present on the gold surfaces. Atomic force microscopy (AFM) imaging confirms the vertical alignment mode of SWCNT attachment through significant changes in surface roughness compared to bare gold surfaces and the lack of any horizontally aligned SWCNTs present. These SWCNT assemblies are further modified with an amine-terminated single-stranded probe-DNA. Subsequent hybridization of the surface-bound probe-DNA in the presence of complementary strands in solution is followed using impedance measurements in the presence of Fe(CN)6 (3-/4-) as the redox probe in solution, which show changes in the interfacial electrochemical properties, specifically the charge-transfer resistance, due to hybridization. In addition, hybridization of the probe-DNA is also compared when it is attached directly to the gold surfaces without any intermediary SWCNTs. Contrary to our expectations, impedance measurements show a decrease in charge-transfer resistance with time due to hybridization with 300 nM complementary DNA in solution with the probe-DNA attached to SWCNTs. In contrast, an increase in charge-transfer resistance is observed with time during hybridization when the probe-DNA is attached directly to the gold surfaces. The decrease in charge-transfer resistance during hybridization in the presence of VASWCNTs indicates an enhancement in the electron transfer process of the redox probe at the VASWCNT-modified electrode. The results suggest that VASWCNTs are acting as mediators of electron transfer, which facilitate the charge transfer of the redox probe at the electrode-solution interface.

Outcomes after early splenectomy for hematological disorders.

PURPOSE: Acute splenic sequestration crisis is a devastating complication of sickle cell disease that can require prophylactic splenectomy. Historically, splenectomy before 5 years of age was avoided because of fear of overwhelming postsplenectomy sepsis. Recently, splenectomy has been performed as early as 2 years of age, but the safety of this approach is unknown. This study compared outcomes of splenectomy performed in patients under 5 years of age with those 5 years of age and older. MATERIALS AND METHODS: A retrospective chart review of patients registered in a children's hospital hematology database was performed to examine intraoperative and postoperative outcomes after splenectomy. Statistical data analysis included Fisher's exact tests for categorical variables and the nonparametric median test for continuous variables. RESULTS: From 1997 to 2012, 30 sickle cell patients underwent splenectomy. At surgery, 18 of the 30 patients were under 5 years of age (Group 1), and 12 patients were 5 years of age or older (Group 2). Almost all procedures were laparoscopic. Both group had similar operative times, rates of conversion, and frequencies of complications. Both groups had similar lengths of follow-up (median, 62 months for Group 1 versus 63 months for Group 2). No portal vein thromboses or postsplenectomy sepsis events occurred in either group. CONCLUSIONS: In this study, there was no evidence that the incidence of complications was higher after splenectomy at a younger age. A large, multicenter study is needed to further evaluate the safety of this practice.

Anxiety phenotype in mice that overexpress protein kinase A.

The role of cyclic adenosine monophosphate/protein kinase A (cAMP/PKA) signaling in the molecular pathways involved in fear and memory is well established. Prior studies in our lab reported that transgenic mice with an inactivating mutation in Prkar1a gene (codes for the 1-alpha regulatory subunit (R1α) of PKA) exhibited behavioral abnormalities including anxiety and depression. In the present study, we examined the role of altered PKA signaling on anxiety-like behaviors in Prkar1a(+/-) mice compared to wild-type (WT) littermates. The elevated plus maze (EPM) and marble bury (MB) tests were used to assess anxiety-like behavior. The hotplate test was performed to evaluate analgesia. We further examined the impact of the Prkar1a inactivating mutation on PKA activity in specific nuclei of the brain associated with anxiety-like behavior. Results for the MB test showed a genotype effect, with increased anxiety-like behavior in Prkar1a(+/-) mice, compared to WT littermates (p<0.05). MANOVA analysis showed a significant genotype difference in anxiety-like behavior in the EPM between WT and Prkar1a(+/-) mice on combined dependent variables (open arm time and open to total time ratio; p<0.05). Results of hotplate testing showed no genotype effect however; the expected sex difference was noted. Analysis of PKA activity showed the loss of one Prkar1a allele led to an increase in basal and cAMP-stimulated kinase activity in both the basolateral and central amygdala. These results suggest that the alteration in PKA signaling in Prkar1a(+/-) mice is not a ubiquitous effect; and supports the importance of cAMP/PKA pathway in neurobiological processes involved in anxiety and fear sensitization.

Anthropometric measures and fasting insulin levels in children before and after cure of Cushing syndrome.

BACKGROUND & AIMS: Children with Cushing syndrome present with growth delay and excess adiposity that tends to be generalized rather than centripetal. There are no prospective studies of this phenotype as it evolves before and after treatment in children. The aims of this study were to evaluate children prior to and one-year after surgical cure compared to controls and to determine fasting insulin levels and their possible association with waist circumference and waist-height ratio, pre- and post-cure of Cushing syndrome. METHODS: 30 children with Cushing syndrome were evaluated prior to and one-year post-treatment and compared to 14 age and body mass index-matched controls. RESULTS: Only triceps skin fold z- score showed a significant difference between patients with active Cushing syndrome and controls. A positive correlation between fasting insulin levels and waist circumference z- score was found for children with Cushing syndrome; this association persisted one-year following cure. CONCLUSIONS: Unlike adults affected with Cushing syndrome, upper arm muscle area of children with Cushing syndrome did not differ from obese children without Cushing syndrome. The persistence of a positive correlation between waist circumference and fasting insulin despite remission of Cushing syndrome suggests that children with a history of Cushing syndrome may have an increased risk for adverse long-term effects of increased abdominal fat mass.