Investigation of the immunoreactivities of NOS enzymes and the effect of sumatriptan in adolescent rats using an experimental model of migraine

The aim was to investigate the immunoreactivities for NOS enzymes in frontal cortex and meningeal vessels after chemical stimulation of the subarachnoid space of adolescent rats and the effect of sumatriptan pre-treatment on the immunoreactivities of the NOS enzymes. Male adolescent Wistar rats were used. Rats in group 1 did not taken intracisternal injection. Rats in group 2 were taken intracisternal autologous blood injection, but no sumatriptan pre-treatment. Rats in group 3 were taken intracisternal autologous blood injection, but they were taken sumatriptan pre-treatment. Tissue samples were investigated for the presence of NOS immunoreactivity. The mean values of immunolabeling intensities for NOS enzymes in frontal cortex and meningeal vessels were significantly increased in group 2 compared to group 1. The mean values of immunolabeling intensities for NOS enzymes in frontal cortex and meningeal vessels were significantly reduced in group 3 compared to group 2. These results suggest that, chemical stimulation of the subarachnoid space increased the immunoreactivities of NOS enzymes in the brain of adolescent rats. The increased NOS immunoreactivities could be antagonized by pre-treatment with sumatriptan.     

Magnetic resonance imaging of mouse skeletal muscle to measure denervation atrophy

We assessed the potential of different MRI measures to detect and quantify skeletal muscle changes with denervation in two mouse models of denervation/neurogenic atrophy. Acute complete denervation and chronic partial denervation were examined in calf muscles after sciatic nerve axotomy and in transgenic SOD1^G93A mice, respectively. Serial T₂, diffusion tensor, and high resolution anatomical images were acquired, and compared to behavioral, histological, and electrophysiological data. Increase in muscle T₂ signal was first detected after sciatic nerve axotomy. Progressive muscle atrophy could be monitored with MRI-based volume measurements, which correlated strongly with postmortem muscle mass measurements. Significant increase in muscle fractional anisotropy and decreases in secondary and tertiary eigenvalues obtained from diffusion tensor imaging (DTI) were observed after denervation. In SOD1^G93A animals, muscle denervation was detected by elevated muscle T₂ and atrophy in the medial gastrocnemius at 10 weeks. Changes in T₂ and muscle volume were first observed in medial gastrocnemius and later in other calf muscles. Alterations in secondary and tertiary eigenvalues obtained from DTI were first observed in tibialis anterior and medial gastrocnemius muscles at age 12 weeks. We propose that MRI of skeletal muscle is a sensitive surrogate outcome measure of denervation atrophy in animal models of neuromuscular disorders, with potential applicability in preclinical therapeutic screening studies in rodents.     

The effect of maturation and age on oestrogen-induced functional hypertrophy of the female rabbit bladder

OBJECTIVE: To evaluate the effect of maturation and ageing on oestrogen-induced functional hypertrophy of the female rabbit bladder. MATERIALS AND METHODS: Twenty female rabbits were separated into two groups of 10 each by age, young (immature) and old rabbits and each age group was subdivided into three subgroups. The rabbits in subgroup 1 were controls, subgroup 2 were ovariectomized (Ovx) and subgroup 3 were Ovx and received 17-beta oestradiol (1 mg/kg/day) by a subcutaneous slow-release tablet implant. After 15 days of treatment, the rabbits were killed, the bladder was excised, and the body and base separated; two full-thickness longitudinal strips from the ventral surface of the bladder body, and one full-thickness strip from the base, were prepared for contractile studies. The contractile responses to electrical-field stimulation, carbachol, ATP and KCl were determined for both the bladder body and base strips. In addition, full-thickness strips of bladder body and base were fixed in formalin for histological and immunohistological studies. RESULTS: Ovx plus oestradiol resulted in significant increases in bladder weight and responses to all forms of stimulation in young and old rabbits (except for the response to KCl). Vascular density and the smooth muscle (SM)/collagen ratio significantly increased after oestradiol replacement. Interestingly, the increase in vascular density was greater in the young than in the old rabbits. CONCLUSIONS: The present study shows that oestrogen supplementation mediates a functional hypertrophy characterized by increased contractile responses to all forms of stimulation in both young and old rabbits. The increased contractile responses might be explained by the increases in vascular density and SM/collagen ratio.     

Frontal infundibular cells: pathway to the frontal sinus

A frontal infundibular cell (FIC) is an uncommon anatomic variant of an anterior ethmoid pneumatization that originates from the frontal recess and typically extends into the lumen of the frontal sinus ostium. FICs may show several anatomic variants that impact the anatomy of the frontal recess. Familiarity with these variants is required for safe endoscopic sinus surgical procedures. We conducted a retrospective chart review, examining 1,040 frontal recesses in 520 adults with no frontal sinus disease, to explore the anatomy of the healthy frontal recess and to describe the prevalence of FICs in patients without a history of conditions that cause frontal pneumatization. Review of axial and coronal computed tomography data, which were reformatted for sagittal reconstruction, was performed at a computer workstation. Bent and Kuhn's classification was used to define types of FICs. We identified 167 patients (32.1%) as having unilateral or bilateral FICs. Type I infundibular cells were the most common type (found in 15.7% of the entire study population). Type II and type III FICs were found in 3.8% and 12.1%, respectively; type IV FICs were present in 0.4%. The FIC has not been emphasized as an important potential cause of frontal sinus obstruction in the radiology literature, but clinicians should specifically watch for it on all routine computed tomography of the frontal sinus. Fine-cut computed tomography scans aid in the identification of each individual cell and allow the surgeon to formulate a clear and precise surgical plan. A surgical plan with a thorough understanding of the anatomy enables confident dissection of this complex and difficult area.