Ultrasound analysis of cervical paraspinal muscles for needle EMG examination.

BACKGROUND: Ultrasound was used to determine optimal needle insertion parameters and assess the vasculature of paraspinal muscles at C5-T1 spinal levels across patients with different body mass indices (BMIs). METHODS: Thirty patients underwent ultrasound examination of the cervical paraspinal muscles at the C5-T1 levels. Images were analyzed to determine the optimal distance and angle of needle insertion to reach the base of the right lamina. Color and spectral Doppler analysis were used to identify and map paraspinal blood vessels. RESULTS: Mean distances and angles varied from 35.1 mm and 17.27 degrees for the low BMI group at C5 to 65.1 mm and 9.85 degrees for the high BMI group at T1. Paraspinal blood vessel mapping revealed a random distribution of vasculature. CONCLUSIONS: Longer distances and steeper angles of needle insertion are required for patients with higher BMIs. Cervical paraspinal arteries vary in distribution and can be visualized with ultrasound.

Magnetic resonance imaging findings of bilateral thalamic involvement in severe paroxysmal sympathetic hyperactivity: a pediatric case series.

PURPOSE: Paroxysmal sympathetic hyperactivity is a complication of brain injury that has mainly been described in the adult brain injury literature. METHODS: We present a case series of three pediatric patients that developed paroxysmal sympathetic hyperactivity of varying severity following hypoxic brain injury. RESULTS: Comparison of brain magnetic resonance imaging revealed bilateral and symmetric global ischemic changes in all three cases. However, the thalamus was not affected in the patient with the mild case of paroxysmal sympathetic hyperactivity. In contrast, bilateral and symmetric damage to the thalamus was observed in the two severe cases. CONCLUSIONS: Our case series suggests that in hypoxic brain injury, evidence of bilateral ischemic injury to the thalamus on magnetic resonance imaging may be an important early predictor of severity and length of paroxysmal sympathetic hyperactivity. While this is an interesting observation, definite proof of our hypothesis requires further research including analysis of larger numbers of patients and comparison of MRI findings in children with hypoxic brain injury that do not develop paroxysmal sympathetic hyperactivity.

The correlation of dystonia severity and serum transaminases in a child with a brain injury.

BACKGROUND: Severe anoxic brain injury can lead to prolonged episodes of status dystonicus. Sustained dystonia can result in skeletal muscle breakdown and elevation of serum transaminases, which can initially be confused with polypharmacy-related hepatotoxicity or an underlying metabolic condition. PATIENT: We present a 19-month-old boy who sustained a severe anoxic brain injury in the setting of a viral upper respiratory tract infection. Within 2 weeks after injury, he developed prolonged periods of severe dystonia. RESULTS: Serum creatine kinase peaked at 4504 U/L, alanine transaminase at 183 U/L, and aspartate transaminase at 198 U/L. CONCLUSIONS: This child demonstrated a clear correlation between severity of dystonia after brain injury and changes in serum alanine transaminase, aspartate transaminase, and creatine kinase. In the literature, aspartate transaminase and alanine transaminase elevations have been reported in seizures, myopathies, and extreme exercise. This is the first report of serum transaminase elevation secondary to dystonia. Early identification of skeletal muscle causes of increased alanine transaminase and aspartate transaminase may prevent unnecessary investigations and can reduce concern about medication-related hepatotoxicity.

Structural and functional analysis of Saccharomyces cerevisiae Mob1.

The Mob proteins function as activator subunits for the Dbf2/Dbf20 family of protein kinases. Human and Xenopus Mob1 protein structures corresponding to the most conserved C-terminal core, but lacking the variable N-terminal region, have been reported and provide a framework for understanding the mechanism of Dbf2/Dbf20 regulation. Here, we report the 2.0 A X-ray crystal structure of Saccharomyces cerevisiae Mob1 containing both the conserved C-terminal core and the variable N-terminal region. Within the N-terminal region, three novel structural elements are observed; namely, an alpha-helix denoted H0, a strand-like element denoted S0 and a short beta strand denoted S-1. Helix H0 associates in an intermolecular manner with a second Mob1 molecule to form a Mob1 homodimer. Strand S0 binds to the core domain in an intramolecular manner across a putative Dbf2 binding site mapped by Mob1 temperature-sensitive alleles and NMR binding experiments. In vivo functional analysis demonstrates that Mob1 mutants that target helix H0 or its reciprocal binding site are biologically compromised. The N-terminal region of Mob1 thus contains structural elements that are functionally important.