Applications of a Novel Microangioscope for Neuroendovascular Intervention

BACKGROUND AND PURPOSE

Visualization in neuroendovascular intervention currently relies on biplanar fluoroscopy and contrast administration. With the advent of endoscopy, direct visualization of the intracranial intravascular space has become possible with microangioscopes. We analyzed the efficacy of our novel microangioscope to enable direct observation and inspection of the cerebrovasculature, complementary to a standard fluoroscopic technique.

MATERIALS AND METHODS

Iterations of microangioscopes were systematically evaluated for use in neurodiagnostics and neurointerventions in both live animal and human cadaveric models. Imaging quality, trackability, and navigability were assessed. Diagnostic procedures assessed included clot identification and differentiation, plaque identification, inspection for vessel wall injury, and assessment of stent apposition. Interventions performed included angioscope-assisted stent-retriever thrombectomy, clot aspiration, and coil embolization.

RESULTS

The microangioscope was found helpful in both diagnosis and interventions by independent evaluators. Mean ratings of the imaging quality on a 5-point scale ranged from 3.0 (clot identification) to 4.7 (Pipeline follow-up). Mean ratings for clinical utility ranged from 3.0 (aspiration thrombectomy) to 4.7 (aneurysm treatment by coil embolization and WEB device).

CONCLUSIONS

This fiber optic microangioscope can safely navigate and visualize the intravascular space in human cadaveric and in vivo animal models with satisfactory resolution. It has potential value in diagnostic and neurointerventional applications.

Resistance training increases glucose uptake and transport in rat skeletal muscle

The aim of this investigation was to determine if resistance training exercise improved glucose uptake and transport in rodent skeletal muscle. Sprague-Dawley rats were assigned to one of the three groups: control (CON), resistance trained (RT) and aerobic exercise trained (AT). Resistance trained rats were placed in a rodent squat apparatus and performed three sets of 10 repetitions at 75% of their one repetition maximum 3 days week-1 for 12 weeks. Aerobic exercise training consisted of running the rats 3 days week-1 for 45 min over a 12-week period on a motor-driven treadmill (32 m min-1, 15% grade). Following the training period, all animals were subjected to hind limb perfusion in the presence of 500 microU mL-1 insulin. Hind limb glucose uptake was similar in the RT (9.91 +/- 0.7 micromol g-1 h-1) and AT (10.23 +/- 1.0 micromol g-1 h-1) animals and significantly greater than control (CON) (6.40 +/- 0.6 micromol g-1 h-1). Rates of 3-O-methyl-d-glucose transport in the RT animals were elevated in the muscles utilized for RT while in the AT animals rates of 3-O-methyl-d-glucose transport were increased in those muscles recruited for running. The increased rates of 3-O-methyl-d-glucose transport in the skeletal muscles of the resistance trained and aerobic exercise trained animals appeared to be, in part, because of an increased GLUT4 protein concentration. These findings suggest that both resistance or aerobic training exercise can improve insulin-stimulated skeletal muscle glucose uptake and transport, but the training adaptations are restricted to the muscles recruited for the exercise performance.

Simultaneous screening for three correlated lipids in the VA HDL Intervention Trial

We developed methodology to design the multistage lipid screen for the VA HDL Intervention Trial, a randomized double-blind placebo-controlled secondary prevention clinical trial of 2531 participants. The trial aimed to determine if HDL-raising therapy reduces coronary events in men with low HDL-cholesterol and desirable LDL-cholesterol. Joint lipid distributions for HDL-cholesterol, LDL-cholesterol, and triglycerides were derived on the basis of estimates from previous studies, and simulations were performed to determine the cutpoints for excluding screenees for the three lipid parameters to be used at each recruitment stage. Operating characteristics for different screening rules are presented. Comparisons between the predicted and actual study recruitment results show good agreement in lipid characteristics and underscore the complexity of simultaneously screening on correlated continuous physiologic parameters such as lipids.

Stabilized resection arthroplasty by an anterior approach in trapeziometacarpal arthritis: results and surgical technique

Resection arthroplasties were performed through a carpal tunnel incision in 72 hands of 57 patients with trapeziometacarpal joint arthritis and coexistent pathology of the anterior hand or wrist. Sixty-nine hands were followed for an average of 44 (range, 12-74 months). Pain relief was excellent in 60 hands, good in 7, and fair in 2, and thumb motion was satisfactory in 64 hands. Mean strength increase was 30%. Scaphometacarpal space loss was 0.5 mm each year, and residual space averaged 3.1 mm at 60 months. There were two failures. The study corroborated the frequent coexistence of other pathology of the anterior area of the hand and wrist, specifically, carpal tunnel syndrome and flexor carpi radialis tenosynovitis. Furthermore it demonstrated the possibility of an anterior approach to treat these conditions via the same incision. After 5 years, functional results remained good despite progressive collapse of the scaphometacarpal space.

Faculty differences in replacement decisions for amalgam restorations

During a 15-week period, six full-time faculty members supervised the replacement of amalgam restorations by clinical dental students. The tooth numbers, the amalgam surfaces replaced, the reasons for replacement, and the instructors were compared. The students removed 956 surfaces of amalgam from 436 teeth. The primary reasons cited for replacement were marginal breakdown (69%) and caries (33%).

Matrix vesicle biogenesis in vitro by rachitic and normal rat chondrocytes

Calcifying matrix vesicles (MVs) are released from chondrocytes and osteoblasts in monolayer culture. In the present studies, we tested the ability of rachitic versus normal rat growth plate chondrocytes in micromass or monolayer primary cultures to produce MVs. Unlike earlier reports of in vitro MV biogenesis by chicken chondrocytes in which most MVs were released into the medium, we found that most of the released rat matrix vesicles were entrapped in a newly formed cartilaginous matrix enveloping the cells. These matrix-associated MVs could be isolated by mild collagenase treatment and concentrated by differential centrifugation. Vesicle production slowed in the older 2- to 4-week-old cultures and, unlike vesicle release from cultured chicken chondrocytes, active vesicle production did not show a second burst of activity at 3 to 4 weeks. Alkaline phosphatase (ALP) activity diminished with time in culture in cells and matrix vesicles, suggesting a decrease in differentiative expression. Protein profiles on SDS polyacrylamide gels of native matrix vesicles and culture-derived MVs from rachitic and normal cells were quite similar and showed a typical simplified protein pattern as compared to chondrocyte plasma membrane proteins. There were distinctive proteins migrating at 130, 80 to 95, 66, 43, 20, and 14 kd. Culture-derived MVs showed vigorous in vitro calcifying activity that was ALP related. We conclude that 1) rachitic chondrocytes are essentially normal in their matrix vesicle production; 2) matrix entrapment of MVs is a characteristic of rat chondrocyte cultures; and 3) culture-produced MVs are similar to native MVs in protein profile and calcifiability, and thus can be studied as a model for normal MV composition and calcification.

Stereoscopic threshold in children and adults

The threshold of stereoacuity is reported as measured on 369 normal children aged 3 to 7 years, and on 51 normal adults. Four standard clinical stereotests were used and two different testing procedures adopted. The results show that both threshold and variability decrease with age, and performance becomes adult-like at different ages for different tests. Interest correlations are poor, and in cases where the correlation is significant, no identifiable pattern emerges between testing procedures, age, and stereotests. The procedures themselves gave no significant difference in stereoacuity values between all four tests.