Case report: Takayasu arteritis in a 3-month-old Chinese girl.

RATIONALE: Takayasu arteritis is a rare large vessel systemic vasculitis that predominantly affects the aorta and its main branches in women of childbearing age. Due to nonspecific symptoms during the acute phase of disease, early diagnosis is still a challenge for pediatricians. PATIENT CONCERNS: We reported a 3-month-old girl who presented with sustained elevated levels of acutephase reactants, which could not be explained by infectious diseases and malignant diseases. DIAGNOSES: The patient's angiography showed dilatation, stenosis, and inflammation of the aorta and its branches and was diagnosed as Takayasu arteritis. INTERVENTIONS: We prescribed glucocorticoids combined with immunosuppressive agents, which include cyclophosphamide used as an induction drug for 6 months, and mycophenolate mofetil used as a maintenance drug. Glucocorticoids gradually stopped. OUTCOMES: At present, the girl went into clinical remission with normal levels of acute-phase reactants and improvement of vascular inflammation demonstrated by angiography. LESSONS: This case report illustrates that Takayasu arteritis can occur in children at a very early age after birth before apparent clinical symptoms.

Stable folding core in the folding transition state of an alpha-helical integral membrane protein.

Defining the structural features of a transition state is important in understanding a folding reaction. Here, we use Φ-value and double mutant analyses to probe the folding transition state of the membrane protein bacteriorhodopsin. We focus on the final C-terminal helix, helix G, of this seven transmembrane helical protein. Φ-values could be derived for 12 amino acid residues in helix G, most of which have low or intermediate values, suggesting that native structure is disrupted at these amino acid positions in the transition state. Notably, a cluster of residues between E204 and M209 all have Φ-values close to zero. Disruption of helix G is further confirmed by a low Φ-value of 0.2 between residues T170 on helix F and S226 on helix G, suggesting the absence of a native hydrogen bond between helices F and G. Φ-values for paired mutations involved in four interhelical hydrogen bonds revealed that all but one of these bonds is absent in the transition state. The unstructured helix G contrasts with Φ-values along helix B that are generally high, implying native structure in helix B in the transition state. Thus helix B seems to constitute part of a stable folding nucleus while the consolidation of helix G is a relatively late folding event. Polarization of secondary structure correlates with sequence position, with a structured helix B near the N terminus contrasting with an unstructured C-terminal helix G.