T cell–derived interleukin (IL)-21 promotes brain injury following stroke in mice

T lymphocytes are key contributors to the acute phase of cerebral ischemia reperfusion injury, but the relevant T cell–derived mediators of tissue injury remain unknown. Using a mouse model of transient focal brain ischemia, we report that IL-21 is highly up-regulated in the injured mouse brain after cerebral ischemia. IL-21–deficient mice have smaller infarcts, improved neurological function, and reduced lymphocyte accumulation in the brain within 24 h of reperfusion. Intracellular cytokine staining and adoptive transfer experiments revealed that brain-infiltrating CD4+ T cells are the predominant IL-21 source. Mice treated with decoy IL-21 receptor Fc fusion protein are protected from reperfusion injury. In postmortem human brain tissue, IL-21 localized to perivascular CD4+ T cells in the area surrounding acute stroke lesions, suggesting that IL-21–mediated brain injury may be relevant to human stroke

Reversal of Fragile X Phenotypes by Manipulation of AβPP/Aβ Levels in Fmr1KO Mice

Fragile X syndrome (FXS) is the most common form of inherited intellectual disability and the leading known genetic cause of autism. Fragile X mental retardation protein (FMRP), which is absent or expressed at substantially reduced levels in FXS, binds to and controls the postsynaptic translation of amyloid β-protein precursor (AβPP) mRNA. Cleavage of AβPP can produce β-amyloid (Aβ), a 39–43 amino acid peptide mis-expressed in Alzheimer's disease (AD) and Down syndrome (DS). Aβ is over-expressed in the brain of Fmr1KO mice, suggesting a pathogenic role in FXS. To determine if genetic reduction of AβPP/Aβ rescues characteristic FXS phenotypes, we assessed audiogenic seizures (AGS), anxiety, the ratio of mature versus immature dendritic spines and metabotropic glutamate receptor (mGluR)-mediated long-term depression (LTD) in Fmr1KO mice after removal of one App allele. All of these phenotypes were partially or completely reverted to normal. Plasma Aβ1–42 was significantly reduced in full-mutation FXS males compared to age-matched controls while cortical and hippocampal levels were somewhat increased, suggesting that Aβ is sequestered in the brain. Evolving therapies directed at reducing Aβ in AD may be applicable to FXS and Aβ may serve as a plasma-based biomarker to facilitate disease diagnosis or assess therapeutic efficacy

The Fetal Growth And Development Of Otoconia In The Vestibular Apparatus Of The Rat.

PhDAnatomy & physiologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/178561/2/7907162.pd

Progressive multifocal leukoencephalopathy after fludarabine therapy for low-grade lymphoproliferative disease.

To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldFludarabine is becoming the initial therapy for low-grade lymphoproliferative malignancies, such as CLL and follicular lymphoma. Fludarabine is highly immunosuppressive in addition to being myelosuppressive and has been associated with neurotoxicity. Progressive multifocal leukoencephalopathy (PML) is an infection with JC virus of the white matter of the central nervous system seen mostly in immunosuppressed patients. We describe two patients treated with fludarabine who developed PML. Immunolabeling was positive for JCV in both patients, but PCR was repeatedly negative in one of them. We suggest that fludarabine may increase the risk of PML in patients with lymphoproliferative diseases

Mitochondrial DNA–Deletion Mutations Accumulate Intracellularly to Detrimental Levels in Aged Human Skeletal Muscle Fibers

Skeletal muscle–mass loss with age has severe health consequences, yet the molecular basis of the loss remains obscure. Although mitochondrial DNA (mtDNA)–deletion mutations have been shown to accumulate with age, for these aberrant genomes to be physiologically relevant, they must accumulate to high levels intracellularly and be present in a significant number of cells. We examined mtDNA-deletion mutations in vastus lateralis (VL) muscle of human subjects aged 49–93 years, using both histologic and polymerase-chain-reaction (PCR) analyses, to determine the physiological and genomic integrity of mitochondria in aging human muscle. The number of VL muscle fibers exhibiting mitochondrial electron-transport-system (ETS) abnormalities increased from an estimated 6% at age 49 years to 31% at age 92 years. We analyzed the mitochondrial genotype of 48 single ETS-abnormal, cytochrome c oxidase–negative/succinate dehydrogenase–hyperreactive (COX(−)/SDH(++)) fibers from normal aging human subjects and identified mtDNA-deletion mutations in all abnormal fibers. Deletion mutations were clonal within a fiber and concomitant to the COX(−)/SDH(++) region. Quantitative PCR analysis of wild-type and deletion-containing mtDNA genomes within ETS-abnormal regions of single fibers demonstrated that these deletion mutations accumulate to detrimental levels (>90% of the total mtDNA)

Intramedullary disseminated sporotrichosis in an immunocompetent patient: case report and review of the literature

Abstract Background Disseminated sporotrichosis is a severe opportunistic infection that often affects immunocompromised patients after a cutaneous inoculation. Here we present a rare case of disseminated sporotrichosis discovered as a solitary intramedullary thoracic spinal cord lesion in an immunocompetent patient. Case description A 37-year-old man presented with progressive lower limb weakness and sensory changes over 1 week. A spinal magnetic resonance imaging (MRI) revealed a contrast-enhancing intramedullary lesion centered at T10. The patient was afebrile and reported no history of trauma or cutaneous lesions. The lesion was unresponsive to a trial of corticosteroids. A thoracic laminectomy was performed and a biopsy obtained. A cutaneous lesion on the arm was concurrently discovered, which was also biopsied. Both the skin and spinal cord biopsies showed Sporothrix schenckii by macroscopic and microscopic morphology which were later confirmed by MALDI-TOF mass spectrometry. Conclusion This is a rare case of intramedullary disseminated sporotrichosis affecting the central nervous system of an immunocompetent patient. This unusual presentation should be taken into consideration when such intramedullary lesions are encountered

Friedreich's ataxia associated with mitochondrial myopathy: clinicopathologic report.

A 13-year-old boy with clinical and electrophysiologic findings of Friedreich's ataxia developed unusually prominent myopathy. Skeletal muscle biopsy showed mitochondrial proliferation and structural abnormalities. No mutation was found in skeletal muscle mitochondrial DNA to explain this finding. Molecular genetic and pathologic studies confirmed a diagnosis of Friedreich's ataxia in the proband and affected relatives. Although the Friedreich's ataxia phenotype results from decreased expression of a mitochondrially targeted protein, frataxin, mitochondrial myopathy has not been described as a feature of the disease. The association between the frataxin gene mutation and mitochondrial myopathy in this case suggests that severe or cumulative insults to mitochondrial function may produce myopathic changes in some cases of Friedreich's ataxia. The patient also responded clinically to carnitine supplementation, suggesting a potential palliative therapy for the disease.Case ReportsJournal Articleinfo:eu-repo/semantics/publishe