Limb muscles of vertebrates are derived from migratory dermomyotomal cells which emanate from a limited number of somites located adjacent to the developing limb buds. We have generated additional limb buds in chicken embryos by implantation of FGF-beads into the interlimb region in order to analyze whether these somites can be programmed to supply ectopic limbs with myogenic precursor cells. We show that migrating myogenic precursor cells are released from somites at the level of the newly formed limb, even when cell migration into the natural limb has been completed. The implantation of FGF beads in the lateral plate mesoderm rapidly induces SF/HGF expression. FGF beads implanted between HH stages 10 and 12 inhibit limb bud formation or shift the normal limb position. When an additional FGF bead was implanted at the original limb position at HH stage 15, SF/HGF expression was transiently induced to low levels without inducing a new limb. This demonstrates that the initial induction of SF/HGF by FGF does not require limb formation. Expression of SF/HGF during early limb bud stages was found in the entire developing bud and the adjacent lateral plate mesoderm with direct contacts to the lateral edge of the dermomyotome. Later, the SF/HGF expression domain retracts to a distal region below the apical ectodermal ridge. To investigate the role of SF/HGF in the migratory process, we implanted beads soaked in SF/HGF-alone or together with FGF into different locations of the developing chick embryo. In the experiments SF/HGF caused delamination of migratory cells from the dermomyotomal epithelium but no chemotactic attraction of migrating cells toward the SF/HGF source.
1H-MR spectra of human skeletal muscle feature peak splittings due to dipolar coupling. Quantitative difference spectroscopy in a double-blind cross-over trial testing oral creatine supplementation revealed that most of the resonances affected by dipolar coupling can be assigned to creatine and/or phosphocreatine. The assignment was performed in two different skeletal muscles and confirmed by measurements at the magic angle where dipolar splittings vanish. Numerical spectral simulations revealed that the observed spectra are consistent with partly-averaged dipolar coupling among methylene and methyl protons of (phospho)creatine. The possible nature of the molecular dynamics leading to incomplete dipolar averaging is discussed.
Noninvasive observation of Cr and PCr after Cr supplementation shows an increase in a muscle specific manner. Higher preexercise levels of PCr/ATP at rest compensate for significantly slower recovery rates of PCr/ATP after Cr supplementation.
Cr supplementation is effective in improving short-term performance, and the methods used show no detrimental side effects with this supplementation protocol.
Myf-5 Revisited: Loss of Early is dependent on Myf-5 and a number of potential induc-Myotome Formation Does Not Lead tive signals expressed in myotome like FGFs and PDGF are absent in Myf-5 mutant mice (Grass et al., 1996), to a Rib Phenotype in Homozygous this hypothesis appeared plausible and logical.
Background
Herpes simplex virus (HSV) is commonly associated with oro-facial and genital manifestations. It rarely causes encephalitis and even less commonly, in heavily immunosuppressed patients, visceral disease or bronchopneumonitis. We present a case of cytologically-proven, PCR-positive HSV-1 tracheobronchitis and pneumonitis in a patient with less severe immunocompromise.
Case presentation
A 64 year old white man with steroid-induced diabetes mellitus and progressive small-cell bronchial carcinoma despite chemo- and immunotherapy with two checkpoint inhibitors presented with symptoms of lower respiratory tract infection. Community-acquired pneumonia was suspected and empirical broad-spectrum antibacterial treatment was initiated. Chest CT-scan revealed ground-glass opacities and tree-in bud lesions. Cytology of BAL showed extensive cytopathic effects typically caused by infection with herpes virus and PCR confirmation of HSV-1. Acute phase HSV serology was positive for IgG and borderline for IgM. The patient deteriorated clinically due to tumor progress and infection despite high-dose acyclovir therapy and died 2 weeks after admission.
Conclusions
We report an unusual case of fatal HSV-1 pneumonitis due to reactivation in a patient with lung cancer, steroid-induced diabetes and treatment with two checkpoint inhibitors. In immunosuppressed patients with non-improving pneumonia invasive diagnostic procedures are warranted including cytology and molecular diagnostics.
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