Deficiency of pantothenate kinase 2 (Pank2) in mice leads to retinal degeneration and azoospermia

Pantothenate kinase-associated neurodegeneration (PKAN, formerly known as Hallervorden-Spatz syndrome) is a rare but devastating neurodegenerative disorder, resulting from an inherited defect in coenzyme A biosynthesis. As pathology in the human condition is limited to the central nervous system, specifically the retina and globus pallidus, we have generated a mouse knock-out of the orthologous murine gene (Pank2) to enhance our understanding of the mechanisms of disease and to serve as a testing ground for therapies. Over time, the homozygous null mice manifest retinal degeneration, as evidenced by electroretinography, light microscopy and pupillometry response. Specifically, Pank2 mice show progressive photoreceptor decline, with significantly lower scotopic a- and b-wave amplitudes, decreased cell number and disruption of the outer segment and reduced pupillary constriction response when compared with those of wild-type littermates. Additionally, the homozygous male mutants are infertile due to azoospermia, a condition that was not appreciated in the human. Arrest occurs in spermiogenesis, with complete absence of elongated and mature spermatids. In contrast to the human, however, no changes were observed in the basal ganglia by MRI or by histological exam, nor were there signs of dystonia, even after following the mice for one year. Pank2 mice are 20% decreased in weight when compared with their wild-type littermates; however, dysphagia was not apparent. Immunohistochemistry shows staining consistent with localization of Pank2 to the mitochondria in both the retina and the spermatozoa.     

“It’s a Little Different for Men”—Sponsorship and Gender in Academic Medicine: a Qualitative Study

BackgroundWomen remain underrepresented in top leadership positions in academic medicine. In business settings, a person with power and influence actively supporting the career advancement of a junior person is referred to as a sponsor and sponsorship programs have been used to diversify leadership. Little is known about how sponsorship functions in academic medicine.ObjectiveTo explore perceptions of sponsorship and its relationship to gender and career advancement in academic medicine.DesignQualitative study using semi-structured, one-on-one interviews with sponsors and protégés.ParticipantsTwelve sponsors (clinical department chairs) and 11 protégés (participants of a school of medicine executive leadership program [N = 23]) at the Johns Hopkins School of Medicine.Key ResultsAll sponsors were men and all were professors, six of the 11 protégés were women, and four of the 23 participants were underrepresented minorities in medicine. We identified three themes: (1) people (how and who): women seek out and receive sponsorship differently; (2) process (faster and further): sponsorship provides an extra boost, especially for women; and (3) politics and culture (playing favorites and paying it forward): sponsorship and fairness. Informants acknowledge that sponsorship provides an extra boost for career advancement especially for women. Sponsors and protégés differ in their perceptions of how sponsorship happens. Informants describe gender differences in how sponsorship is experienced and specifically noted that women were less likely to actively seek out sponsorship and be identified as protégés compared to men. Informants describe a tension between sponsorship and core academic values such as transparency, fairness, and merit.ConclusionSponsorship is perceived to be critical to high-level advancement and is experienced differently by women. Increased understanding of how sponsorship works in academic medicine may empower individual faculty to utilize this professional relationship for career advancement and provide institutions with a strategy to diversify top leadership positions.KEY WORDS: academic medicine, sponsorship, leadership, gender disparities     

HIV-1 Tat and Cocaine Impair Survival of Cultured Primary Neuronal Cells via a Mitochondrial Pathway

Addictive stimulant drugs, such as cocaine, are known to increase the risk of exposure to HIV-1 infection and hence predispose towards the development of AIDS. Previous findings suggested that the combined effect of chronic cocaine administration and HIV-1 infection enhances cell death. Neuronal survival is highly dependent on the health of mitochondria providing a rationale for assessing mitochondrial integrity and functionality following cocaine treatment, either alone or in combination with the HIV-1 viral protein Tat, by monitoring ATP release and mitochondrial membrane potential (ΔΨm). Our results indicate that exposing human and rat primary hippocampal neurons to cocaine and HIV-1 Tat synergistically decreased both mitochondrial membrane potential and ATP production. Additionally, since previous studies suggested HIV-1 infection alters autophagy in the CNS, we investigated how HIV-1 Tat and cocaine affect autophagy in neurons. The results indicated that Tat induces an increase in LC3-II levels and the formation of Parkin-ring-like structures surrounding damaged mitochondria, indicating the possible involvement of the Parkin/PINK1/DJ-1 (PPD) complex in neuronal degeneration. The importance of mitochondrial damage is also indicated by reductions in mitochondrial membrane potential and ATP content induced by HIV-1 Tat and cocaine.     

Increased Risk for Multidrug-Resistant Tuberculosis in Migratory Workers,Armenia

To understand use of tuberculosis (TB) services for migrant workers, we conducted a cross-sectional census of 95 migrant workers with TB from Armenia by using medical record reviews and face-to-face interviews. Prolonged time between diagnosis and treatment, treatment interruption, and treatment defaults caused by migrant work might increase the risk for multidrug-resistant TB.     

Evaluation of Depression and Quality of Life in Patients With Psoriasis

Objective::To measure the prevalence of depression in patients with psoriasis and to evaluate the relationship between the severity of psoriasis and depression ...     

Pyridoxine-dependent epilepsy: an under-recognised cause of intractable seizures

Pyridoxine-dependent epilepsy (PDE) is a rare autosomal recessive disorder causing intractable seizures in neonates and infants. PDE patients are typically resistant to anti-epileptic treatment but respond to the administration of pyridoxine. Different seizure types have been reported in PDE, and episodes of status epilepticus are common. Electroencephalographic or neuroimaging abnormalities are not pathognomonic for this disorder. Intellectual disability is frequent at the follow-up. Recently, elevated urinary α-aminoadipic semialdehyde has been shown to be a reliable biomarker of this disorder, and mutations in the ALDH7A1 gene, encoding α-aminoadipic semialdehyde dehydrogenase, have been demonstrated in the large majority of PDE patients. However, early consideration of a pyridoxine trial remains the most important issue in a neonate or in an infant with intractable early onset seizures.     

Growth inhibition of malignant glioblastoma by DING protein

Malignant gliomas are a highly aggressive type of brain tumor with extremely poor prognosis. These tumors are highly invasive and are often surgically incurable and resistant to chemotherapeutics and radiotherapy. Thus, novel therapies that target pathways involved in growth and survival of the tumor cells are required for the treatment of this class of brain tumors. Previous studies revealed that epidermal growth factor receptor and extracellular-signal-regulated kinases (ERKs), which are involved in the induction of cell proliferation, are activated in the most aggressive type of glioma, i.e. glioblastoma multiforme (GBM). In fact, GBMs with increased levels of ERK activity exhibit a more aggressive phenotype than the others with moderate ERK activity, pointing to the importance of ERK and its kinase activity in the development and progression of these tumors. In this study, we have evaluated the effect of p38SJ, a novel member of the DING family of proteins, derived from Hypericum perforatum calluses, on the growth of malignant glioma cell lines, T98G and U-87MG by focusing on cell cycle and signaling pathways controlled by phosphorylation of various regulatory proteins including ERK. p38SJ, which exhibits profound phosphatase activity, shows the capacity to affect the phosphorylation status of several important kinases modulating signaling pathways, and cell growth and proliferation. Our results demonstrate that p38SJ reduces glioma cell viability and arrests cell cycle progression at G0/G1. The observed growth inhibitory effect of p38SJ is likely mediated by the downregulation of several cell cycle gatekeeper proteins, including cyclin E, Cdc2, and E2F-1. These results suggest that p38SJ may serve as a potential candidate for development of a therapeutic agent for the direct treatment of malignant gliomas and/or as a potential radiosensitizer.