Clinical outcomes of basilar artery aneurysms

To evaluate the effects of endovascular treatments, we retrospectively analyzed a consecutive series of patients with basilar artery aneurysms (BAAs) treated endovascularly. During a seven year period, 43 patients (mean age 42.2 years, male/female ratio 21:22) with BAAs were treated mainly with endovascular techniques at Beijing Tiantan Hospital. Pretreatment clinical grades were determined using the Hunt-Hess scale. Outcome was evaluated using the Glasgow Outcome Scale scores (GOS) during a mean follow-up period of 21.1 months (range, 1 to 72 months). Forty-three patients had 44 BAAs, one MCA aneurysm and one P1 aneurysm. Endovascular treatment was technically feasible in 40 patients. One aneurysm thrombosed spontaneously after initial angiography. Four (9.3%) patients died periprocedurally. Immediate postprocedural angiograms in 44 BAAs showed that complete occlusion was achieved in 33 BAAs, subtotal occlusion in one and incomplete occlusion in seven. Follow-up angiographic results in 30 patients confirmed complete occlusion of 27 aneurysms, subtotal occlusion in one, and incomplete occlusion in two. Two patients with vertebrobasilar atheromatous fusiform aneurysms were treated with antiplatelet medications. Long-term outcome was good (GOS Score 4 or 5) in 39 patients (90.7%) and fatal (GOS Score 1) in four (9.3%). Favorable overall long-term outcome can be achieved in patients with BA apex aneurysms, and in 78.6% of those with BA trunk aneurysms when using endovascular techniques. Endovascular coil embolization of BAAs is an effective treatment in the long-term. Patients with vertebrobasilar atheromatous fusiform aneurysms can be treated with antiplatelet medications.

Endovascular treatment of brain arteriovenous fistulas

BACKGROUND AND PURPOSE

Brain arteriovenous fistulas (BAVFs) are dangerous lesions with significant risks for hemorrhage and re-hemorrhage; thus, the management of BAVFs is an important subject. Flow disconnection can be accomplished by surgical or endovascular techniques. We reviewed the experience in our endovascular treatment of patients with BAVFs.

MATERIALS AND METHODS

From March 2006 to March 2008, a total of 9 consecutive patients with nontraumatic BAVFs were treated at Beijing Tiantan Hospital. Dural arteriovenous fistulas and Galen aneurysmal malformations were excluded from this study. We retrospectively reviewed the medical records, cerebral angiograms, and endovascular reports for each patient. Radiographic outcome was assessed by posttreatment angiography. Clinical outcome was assessed for every patient.

RESULTS

There were 9 patients with a total of 11 BAVFs. The mean age at presentation was 17.8 years. The clinical presentations were intracranial hemorrhage in 4 patients, headaches in 2 patients, and seizure in 1 patient, with 2 patients diagnosed incidentally. All lesions were supratentorial, and a venous varix was found on angiographic examination. Seven patients were treated with coils, 1 with Onyx-34, and 1 with a combination of coils and glue. All 9 lesions were completely obliterated as demonstrated on follow-up angiographic examination. With a mean follow-up of 5.7 months (range, 3-12 months), all patients were neurologically excellent with no symptoms (modified Rankin Scale, 0).

CONCLUSIONS

BAVFs are more frequent in younger patients and frequently lead to intracranial hemorrhage. Staged endovascular coil embolization of BAVFs may be a good appropriate treatment technique.

Dissecting aneurysm at the proximal anterior cerebral artery treated by parent artery occlusion

Aneurysms of the A1 segment of the anterior cerebral artery (ACA) are rare. We described the first documented endovascular treatment of an A1 portion dissecting aneurysm by parent artery occlusion. A 43-year-old man patient presented with subarachnoid hemorrhage. Cerebral angiography demonstrated a dissecting aneurysm of the left anterior cerebral artery (ACA) at A1 portion. Because of the dissecting nature of the A1 portion aneurysm, a 2.5x15-mm Neuroform stent was placed in the left A1 portion. However, regrowth of the aneurysm was found on the three month follow-up angiogram, so the aneurysm and the left A1 portion of ACA were occluded completely.

Vertebral dissecting aneurysm treated with wingspan stent deployment and detachable coils. A technical note

We describe the first documented endovascular treatment of vertebral dissecting aneurysm using a Wingspan stent and detachable coils. A 54-year-old man presented with a nonruptured vertebral dissecting aneurysm. Because of the dissecting nature of the vertebral aneurysms, a 3x15-mm Wingspan stent was placed in the left vertebral artery. One month later, several detachable coils were introduced into the aneurysm. Six-month follow-up angiogram confirmed the obliteration. Vertebral dissecting aneurysm can be treated with Wingspan stent placement and detachable coils.

Complications related to percutaneous transarterial embolization of intracranial dural arteriovenous fistulas in 40 patients

BACKGROUND AND PURPOSE

An increasing number of intracranial dural arteriovenous fistulas (DAVFs) are amenable to endovascular treatment with Onyx. However, reports on complications caused by this technique have been limited. We present the initial Beijing Tiantan Hospital experience with adverse events related to transarterial Onyx embolization for DAVFs.

MATERIALS AND METHODS

Between September 2005 and February 2008, a total of 40 patients with DAVFs were treated at our institute with Onyx-18. There were 11 women and 29 men with a mean age of 43.15 years (age range, 23-60 years). We reviewed the clinical presentation, angiographic features, treatment, and outcome.

RESULTS

In 40 patients, total obliteration was achieved in 25 DAVFs (62.5%), with the remaining 15 patients not cured with residual shunts. Complications occurred in 9 patients, 5 DAVFs were located at tentorium, 2 were located at the transverse-sigmoid sinus, 1 was found at the inferior petrosal sinus, and 1 was found at the cavernous sinus, leading to permanent disability in 3 patients (morbidity, 7.5%). Complications included reflexive bradyarrhythmia in 3 (7.5%) patients, hemifacial hypoesthesia in 3 (7.5%) patients, hemifacial palsy in 2 (5%) patients, posterior fossa infarction in 2 (5%) patients, jaw pain in 1 (2.5%) patient, microcatheter gluing in 1 (2.5%) patient, hallucinations in 1 (2.5%) patient, and Onyx migration in 1 (2.5%) patient.

CONCLUSION

Although complete cure can be achieved by transarterial embolization with Onyx, the potential for serious complications exists with this procedure.

Photostimulation of astrocytes with femtosecond laser pulses

The involvement of astrocytes in brain functions rather than support has been identified and widely concerned. However the lack of an effective stimulation of astrocytes hampers our understanding of their essential roles. Here, we employed 800-nm near infrared (NIR) femtosecond laser to induce Ca2+ wave in astrocytes. It was demonstrated that photostimulation of astrocytes with femtosecond laser pulses is efficient with the advantages of non-contact, non-disruptiveness, reproducibility, and high spatiotemporal precision. Photostimulation of astrocytes would facilitate investigations on information processing in neuronal circuits by providing effective way to excite astrocytes.

[Survey of the dietary status and physical activity level and fitness of college freshmen in Chengdu]

OBJECTIVE

To study the effect of diet and physical activity on the physical fitness of college students.

METHODS

1200 freshmen come from different five universities in Chengdu were random recruited chosen (600 males and 600 females). A semi-quantitative food frequency questionnaire and international physical activity questionnaire were used, and meanwhile the fitness test was performed.

RESULTS

Micronutrients of iron, zinc, selenium, vitamin E could play important roles in college student fitness. The physical activity level, the time of sitting and the body component could affect college student fitness.

CONCLUSION

Physical activity and diet proved to contribute a lot to the general fitness test system, which is helpful for college students to form healthy habits.

Beam spot size evolution of Gaussian femtosecond pulses after angular dispersion

Beam spot size evolution of spatially Gaussian femtosecond laser pulses after angular dispersion is analyzed and verified with experiments. A general analytical expression for beam spot size at arbitrary propagation distances is obtained, which indicates that beam spot size evolution after angular dispersion is determined by the direct interaction of spectral lateral walk-off by angular dispersion and the intrinsic divergence of the Gaussian beam. This work reveals insights into the propagation of Gaussian femtosecond laser pulses and beams after angular dispersion and may be important for the generation and application of femtosecond laser pulses.

Development of a cell-based assay for monitoring hepatitis C virus ns3/4a protease activity

Hepatitis C virus (HCV) NS3/4A (non-structural 3 and 4 B) protease plays a key role in the processing of polyprotein precursor and it becomes an attractive target for antiviral drug discovery. We developed a cell-based assay for monitoring of the NS3/4A protease activity in mammalian cells that is an important step in screening of specific drugs against the protease. The recombinant caspase 3 (rCasp3) was used as the specific substrate for NS3/4A protease. The endogenous cleavage sites in the procaspase 3 molecule were substituted by decapeptides specific for NS3/4A protease. The activation of rCasp3 depended on its specific cleavage by NS3/4A protease and resulted in an apoptosis of stable cells expressing the protease. The difference in cell viability between the cells expressing NS3/4A protease transfected with rCasp3 and the counterparts pretreated with NS3/4A protease inhibitors could be estimated by a spectrophotometry based on 3-(4,5-dimethylthioazol- 2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) staining of cells in microplates. Thus, we developed a simple and cost-effective colorimetric assay for evaluating NS3/4A protease activity enabling the screening of candidate NS3/4A protease inhibitors.

Trigeminocardiac reflex in embolization of intracranial dural arteriovenous fistula

We report a case of immediate reproducible and reflexive response of asystole upon stimulation of Onyx injection during embolization of a tentorial dural arteriovenous fistula in a 53-year-old man. Upon recognition of the reflexive relationship between Onyx injection and increased vagal tone, the patient was given anticholinergic in an effort to block cholinergic hyperactivity. After atropine was given, no further dysrhythmias occurred.

Dispersion characteristics of acousto-optic deflector for scanning Gaussian laser beam of femtosecond pulses

Pulse evolution after the acousto-optic deflector (AOD) and its dependence on AOD parameters is not clear, but is important to AOD applications in scanning microscopy. By considering the abnormal Bragg AOD as a combination of a dispersion media and a diffraction grating with Littrow structure, the dispersion characteristics of AOD when scanning Gaussian laser beam of femtosecond pulses were analyzed. Pulse width about AOD parameters was explored theoretically and verified with experiments. It is found that after exiting AOD, the pulse width of laser beam either merely decreases or first decreases and then increases before it finally goes steady with the propagation distance, depending on the interaction between the material dispersion and angular dispersion.

Analysis of the dispersion compensation of acousto-optic deflectors used for multiphoton imaging

The acousto-optic deflector (AOD) is highly preferred in laser scanning microscopy for its fast scanning ability and random-addressing capability. However, its application in two-photon microscopy is frustrated by the dispersion of the AOD, which results in beam distortion and pulse lengthening. We report the analysis of simultaneous compensation for the angular dispersion and temporal dispersion of the AOD by merely introducing a single dispersive element such as a prism or a grating. Besides serving as a scanner, the AOD is also a part of the compressor pair by integrating the dispersive nature of the AO interaction. This compensation principle is effective for both one-dimensional (1-D) AOD and two-dimensional (2-D) AOD scanning. Switching from a 1-D to a 2-D system requires proper optical alignment with the compensation element, but does not involve any new components. Analytical expressions are given to illustrate the working principle and to help with understanding the design of the system. Fluorescence images of beads and cells are shown to demonstrate the performance of two-photon microscopy when applying this compensated 2-D AOD as scanner.

Acousto-optic modulator system for femtosecond laser pulses

Femtosecond laser pulses have made a revolution in multiphoton excitation microscopy, micromachining, and optical storage for their unprecedented high peak power. However, modulation of their intensity with acousto-optic modulator (AOM) is frustrated by dispersion which results in a significant stretch in pulse width. Here we report a scheme composed of two acousto-optic deflectors (AODs) to modulate the intensity of the femtosecond laser pulses with simultaneous compensation for the temporal dispersion. With commercial AODs, we demonstrated such an AOM system for the femtosecond laser pulses with overall transmission efficiency of around 80%. The pulse width of the exit beam is 115-177 fs for an input pulse of 110 fs, across the wavelength range of 720-920 nm when the temporal dispersion compensation is optimally tuned at 800 nm. The fluorescence intensity in a two-photon microscopy experiment performed using this system increased 5.5-fold over that of the uncompensated AOM.

Position of the prism in a dispersion-compensated acousto-optic deflector for multiphoton imaging

The performance of a dispersion-compensated acousto-optic deflector (AOD) for steering femtosecond laser pulses was examined with the prism located before or after the AOD, which is regarded as prism-AOD and AOD-prism, respectively. Comparisons are made over parameters including the spot spatial pattern, output pulse width, scanning linearity, the field of view, and the transmission rate. Fluorescence images of 170 nm diameter beads and cells were measured to provide an overall evaluation for these femtosecond laser beam scanning configurations. On the basis of these experiments, the prism-AOD configuration is concluded to be more advantageous for the purpose of simultaneous compensation for the spatial and temporal dispersion.

Simultaneous compensation for spatial and temporal dispersion of acousto-optical deflectors for two-dimensional scanning with a single prism

The dispersive nature of the acousto-optical deflector (AOD) presents a challenge to applications of two sequential orthogonal AODs (a two-dimensional AOD) as XY scanners in multiphoton microscopy. Introducing a prism before the two-dimensional (2D) AOD allows both temporal and spatial dispersion to be compensated for simultaneously. A 90 fs laser pulse was broadened to 572 fs without compensation, and 143 fs with compensation. The ratio of long axis to short axis of the exiting laser beam spot was 3.50 without compensation and 1.14 with compensation. The insertion loss was 37%. Two-photon fluorescence microscopy used the compensated 2D AOD scanner to image a fluorescent microsphere, which improves signal intensity -15-fold compared with the uncompensated scanner.

In vivo DNA-protein interactions at hypersensitive site 3.5 of the human beta-globin locus control region

Using ligation-mediated polymerase chain reaction and in vivo footprinting methods to study the status of DNA-protein interactions at hypersensitive site 3.5 (HS3.5) of the locus control region in K562 and HEL cells, we found that there was protein occupancy in vivo at HS3.5 in both cell lines and the status of DNA-protein interaction was different between K562 and HEL. These data provide direct evidence that specific nuclear factor-DNA complexes form in vivo at functionally important sequence motifs of the HS3.5 in erythroid cells. This indicates that HS3.5 may play an important role in the regulation of the beta-globin gene cluster. K562 is a human erythroleukemia cell line in which the embryonic epsilon-globin gene is predominantly expressed, while the HEL cell line expresses predominantly the fetal beta-globin genes. Thus, HS3.5 might also be involved in the regulation of developmental stage-specific expression of beta-globin genes. Our results are also consistent with the model that each hypersensitive site acts as a functional unit and HS3.5 may facilitate the formation of the HS3 functional unit.