PHOTODYNAMIC THERAPY—AN UPDATE ON CLINICAL APPLICATIONS

Photodynamic therapy(PDT)has received increased attention since the regulatory approvals of several photosensitizers and light applicators in numerous countries and regions around the world.In recent years,much progress has been seen in basic research as well as clinical application.PDT clinical application has now extended from treating malignant diseases to nonmalignant diseases.This review article will present recent clinical data published in English journals.The data will be organized according to their clinical specialties.The new development and future direction in clinical applications of PDT for the management of both malignant and nonmalignant diseases will be discussed.

The sensitivity of neurons with non-periodic activity to sympathetic stimulation in rat injured dorsal root ganglion

Objective The relationship between compressed dorsal root ganglion （DRG） neurons and firing pattern and sensitivity of neurons was studied in chronically the Hindmarsh-Rose （HR） neuronal model. Methods Spontane- ous activities from single fibers of chronically compressed DRG neurons in rats were recorded, and divided into periodic and non-periodic firing patterns. The sensitivity of the two kinds of firing pattern neuron to sympathetic stimulation （SS） was compared. Result It was found that 27.3% of periodic firing neurons and 93.2% of non-periodic firing neurons responded to SS respectively （ periodic vs non-periodic, P 〈 0.01 ）. The responses to SS with different stimulation time were greater non-periodic firing neurons than periodic firing neurons （P 〈 0.01 ）. The non-periodic firing neurons obviously responded to SS. After the firing pattern of these neurons transformed to periodic firing pattern, their responses to SS disappeared or decreased obviously. The HR neuronal model exhibited a significantly greater response to perturbation in non-periodic （chaotic） firing pattern than in periodic firing pattern. Conelusion The non-periodic firing neurons with deterministic chaos are more sensitive to external stimuli than the periodic firing neurons.

Influence of sympathetic stumulating time series on activity of chronically compressed dorsal root ganglion neurons in rat

Objective: To study responses of injured DRG neurons to sympathetic stimulation with different temporal stimulating pattern. Methods: In chronically compressed DRG model, the spontaneous activity of single fiber from the injured DRG neuron was recorded, lumbar sympathetic trunk was electrical stimulated, and the responses of DRG neurons caused by chaotic and periodic sympathetic stimulation were compared. Results: It was found that the response of DRG increased gradually as the sympathetic stimulating frequency increased from 5 Hz to 20 Hz(P<0.01). The chaotic stimulation evoked much greater response than periodic stimulation did, even though the stimulating frequence was similar(P<0.01). Conclusion: Besides the stimulating frequency, the temporal stimulating pattern is one of important factor that effect response of DRG neuron to sympathetic stimulation. The chaotic activity of neurons might be one of effective way to transmit neural information.

Cloning of polyadenylated mRNA fragments of Escherichia coli with restriction display-polymerase chain reaction

Objective:To investigate the polyadenylation of mRNA in E. Coli. Methods: The mRNA of E. Coli was enriched from the total RNA with oligo(dT)-cellulose, prior to reverse transcription using oligo(dT)18as the primer. Double-stranded cDNA was subsequently synthesized, which was subjected to digestion with Sau3A I to produce multiple gene fragments for ligation with the adapters. PCR was carried out in 10 groups according to 10 different pairs of the selective primers, and the PCR products were then cloned into T-vectors. Results: More than 100 gene fragments had been cloned, 30 of which were sequenced. Conclusion:Polyadenylation of E. Coli mRNA may not be a biochemical curiosity but a general attribute of bacterial mRNA.

Three core techniques in surgery of neuroepithelial tumors in eloquent areas： awake anaesthesia, intraoperative direct electrical stimulation and ultrasonography

Background The goal of surgery in the treatment of intrinsic cerebral tumors is to resect the maximum tumor volume,and to spare the eloquent areas. However, it is difficult to discover the eloquent areas intraoperatively due to individual anatomo-functional variability both for sensori-motor and language functions. Consequently, the surgery of intrinsic cerebral tumors frequently results in poor extent of resection or permanent postoperative deficits, or both, and remains a difficult problem for neurosurgeons.Methods From January 2003 to January 2010, 112 patients with neuroepithelial tumors in/close to the eloquent areas were operated on under awake anesthesia with the intraoperative direct electrical stimulation for functional mapping of the eloquent areas. The extent of the tumors was verified by intraoperative ultrasonography. The maximal resection of the tumors and minimal damage of the eloquent areas were the surgical goal of all patients.Results Totally 356 cortical sites in 99 patients were detected for motor response by intraoperative direct electrical stimulation, 50 sites in 16 patients for sensory, 72 sites in 48 patients for language. Sixty-six patients （58.9%） achieved total resection, 34 （30.4%） subtotal and 12 （10.7%） partial. Fifty-eight patients （51.8%） had no postoperative deficit, while 37 patients （33.0%） had transitory postoperative paralysis, 26 patients （23.2%） with transitory postoperative language disturbance and 3 patients （2.7%） with permanent neurological deficits. No patient complained of pain recollection following operation.Conclusions Awake anesthesia, intraoperative direct electrical stimulation and ultrasonography are three core techniques for the resection of intrinsic cerebral tumors near the eloquent areas. This new concept allows an improvement in the quality of surgery for neuroepithelial tumors in/adjacent to eloquent areas.

The anatomical study of transoral atlantoaxial reduction plate internal fixation

Objective： To study relevant anatomical features of the structures involved in transorai atlanto-axiai reduction plate （TARP） internal fixation through transorai approach for treating irreducible atlanto-axiai dislocation and providing anatomical basis for the clinical application of TARP. Methods： Ten fresh craniocervicai specimens were microsurgicaily dissected layer by layer through transorai approach. The stratification of the posterior pharyngeal wail, the course of the vertebral artery, anatomical relationships of the adjacent structures of the atlas and axis, and the closely relevant anatomical parameters for TARP internal fixation were measured. Results： The posterior pharyngeal wall consisted of two layers and two interspaces： the mucosa, prevertebrai fascia, retropharyngeai space, and prevertebrai space. The range from the anterior edge of the foramen magnum to C3 could be exposed by this approach. The thickness of the posterior pharyngeal wall was （ 3.6 ± 0.3 ） mm （ranging 2.9-4.3 mm） at the anterior tubercle of C1, （6.1 ±0.4） mm （ ranging 5.2-7.1 mm） at the lateral mass of C1 and （5.5±0.4） mm （ranging4.3-6.5 mm） at the central part of C2, respectively. The distance from the incisor tooth to the anterior tubercle of C1, C1 screw entry point, and C2 screw entry point was （82.5 ±7.8） mm （ranging71.4-96.2 mm）, （90. 1 ±3.8） mm （ranging 82.2-96.3 mm）, and （89.0±4.1） mm （ranging 81.3- 95.3 mm）, respectively. The distance between the vertebral artery at the atlas and the midline was （25.2 ± 2.3） mm （ ranging 20.4-29.7 mm ） and that between the vertebral artery at the axis and the midline was （ 18.4 _ 2.6 ） mm （ ranging 13.1-23.0 mm）. The allowed width of the atlas and axis for exposure was （39.4 ±2. 2） mm （ ranging 36.2-42. 7 mm ） and （ 39.0 ± 2.1 ） mm （ ranging 35.8-42.3 mm ）, respectively. The distance （ a ） between the two atlas screw insertion points （center of anterior aspect of C1 lateral mass ） was （ 31.4 ± 3.3 ）mm （ ranging 25.4-36.6 mm）. The vertical distance （b） between the line connecting the two C1 screw entry points and that connecting the two C2 screw entry points （at the central part of the vertebrae, namely 3-4 mm lateral to the midline of C2 vertebrae） was （21.3±2.7） mm （ranging 19.4- 24.3mm）, with an a/b ratio of 1.3-1.5. The screws of TARP had a lateral tilt of 12.2°± 0.4° （ranging 10.2° -14.6°at C1 and a medial tilt of 7.3°±0.3° （ranging5.1°-9.4°） at C2 relative to the coronal plane. Conclusions ： An atlanto-axiai surgery through transorai approach is safe and feasible. This approach is suitable for an anterior TARP internal fixation, and the design of the internal fixation system should be based on the above anatomical data.

Transoral atlantoaxial reduction plate fixation for irreducible atlantoaxial dislocation

Objective： To design a clinically applicable transoraipharyngeai atlantoaxiai reduction plate （TARP）, introduce the operation procedure, and evaluate its preliminary clinical effects. Methods： A novel TARP system, including butterfly titanium alloy plate, self-locking screws, atlantoaxial reductor and other operational instruments was developed. This system was applied clinically on five patients with irreducible atlantoaxiai dislocation of congenital or traumatic origin. During operation, the reduction was completed by the combined action of the plate and the atlantoaxiai reductor after transoral joint release and cord decompression. Bone graft granules were implanted between the bilateral atlantoaxiai joints and TARP was used to immobilize subsequently the atlas and axis. Results： Clinical application demonstrated that TARP could induce instant reduction and that the method was operationally feasible and its postoperationai effect was satisfactory. Conclusions： The design of TARP is novel. The operational procedure is simple and easy to use. Furthermore, instant reduction can be completed during the operation and the fixation is relatively stable. TARP is an ideal alternative for irreducible atlantoaxiai dislocation and may have excellent prospects for further clinical applications.