BACKGROUND: Recently, many researches suggest that transcranial magnetic stimulation has effect on learning and memory. Moreover, the effects of magnetic fields simulating electroencephalogram (EEG) rhythm on memory have been investigated.OBJECTIVE: To explore the effect of magnetic field simulating EEG rhythm on memory retrieval ability and its mechanism.DESIGN: Randomized controlled study.SETTING: Department of Medical Imaging, Tianjin Medical University,and School of Precision Instrument & Photoelectronic Engineering, Tianjin University.MATERIALS: The experiment was conducted at the Electroscopic Center of TianjSn Medical University and Laboratory of Biomedical Engineering Department of Tianjin University from February 2002 to February 2004.Totally 25 Wistar rats and 5 domestic cats were selected from the Experimental Animal Center of Tianjin Medical University.INTERVENTIONS: All the 25 Wister rats were randomly divided into 5 group, 4 experimental groups and one control group with 5 rats in each group. Magnetic field simulating EEG rhythm was used to stimulate Wistar rats in the 4 experimental groups, but the time and frequency rate were different. Group 1 was stimulated by weak magnetic field with frequency in α rhythm (10 Hz); Group 2 was stimulated by weak magnetic field with frequency in β rhythm (20 Hz); Group 3 was stimulated by weak magnetic field with frequency changing from α to β rhythm; and Group 4 was stimulated by weak magnetic field with frequency changing from β to α rhythm. Memory retrieval ability and changes of neurotransmitters in the brain were recorded. Five cats were treated with weak magnetic field with frequency changing from α to β rhythm for 20 minutes, and the changes of EEG power spectra before and after stimulation were compared.information from long-term memory was tested with modified cross maze;hippocampus of the rats was measured with high performance liquid multiple-channel electrophysiological recording device.Comparison of memory retrieval ability: Memory retrieval ability in Group 2 and Group 4 was obviously higher than that in control group 5 hours after Content ofdopamine (DA) in rats' cerebral hippocampus: It was obviously higher in the 4 experimental groups than in control group [(192.72±18.66,percentage of power spectrum of β rhythm was increased after stimulation [(23.0±3.4, 14.2±1.3) %.].CONCLUSION: Most of the weak magnetic fields simulating EEG rhythm of human brain can decrease the retrieval of long-term memory, but magnetic field with special rhythm may increase memory retrieval ability.All the effects are related to the release of hippocampal neurotransmitters which is mediated by the change of intracellular calcium ([Ca2+]i) and synaptic vesicle.

Objective To evaluate the relationship between mRNA and protein expression of HtrA and Streptococcus mutans i-solated from the children with different caries experience and to provide the theoretical and experimental basis on prediction of dent-al caries in deciduous teeth .Methods The strains of Streptococcus mutans isolated from children with different carious experiences in the preliminary experiments were divided into three groups :high caries-susceptible group ,middle caries-susceptible group ,caries-free group .All strains were reanimated on the agar plate of MS ,and after smear pure culture examination ,typical bacteria were in-cubated in BHI ,then purified nucleic acid and extracted all the RNA of streptococcus mutans by reverse transcription PCR and de-tected it by agarose gel electrophoresis integrality .Synthetic cDNA and take further PCR amplification with cDNA products .Ob-serve records results by Gel imaging system .HtrA of target gene and electrophoresis image were gray scan by Gel quantitative soft-ware Gel-Pro analyzer 4 .0 was used to analyze relative expression value of gene .After purifying protein ,collected total protein of Streptococcus mutans strains by Western Blot method ,then tested the concentration of total protein sample .The results of Chemilu-minescence imaging were scanned into computer by Bio-Rad analyzing system ,calculated the gray value by software Quantity One 4 .4 .0 which showed the relative expression level of protein .Results There were significant differences in HtrA mRNA and protein expression of different Streptococcus mutans isolated from the children with different caries susceptibility .high caries-susceptible group> middle caries-susceptible group> caries-free group (P< 0 .05) .Conclusion There were significant differences in HtrA mRNA and protein expression of different Streptococcus mutans isolated from the children with different caries susceptibility .The higher caries susceptibility the group was ,the more HtrA mRNA and protein the strain express .

Objective To explore the effect and the mechanism of modulated magnetic pulse fields on memory retention and retrieval ability of rats. Methods The influence of different pulsed magnetic fields on memory performance of rats was evaluated by using cross maze test, the morphological changes of neurons and nerve synapses in the hippocampus of rats were observed by the electronic microscopy. Results The 20 Hz modulated-pulse magnetic field impaired the memory retrieval ability and the memory retention significantly after 1 hour of exposure of the rats to it ( P 0.05). These influences on nerve tissues were also observed in rats underwent the 10Hz modulated magnetic stimulation, manifested as an initial increase in ability of memory in the first 24 hours after the stimulation, but no significant difference from the control was found. The influence of magnetic fields on memory depended on what the rats remembered. Conclusion Changes in the nerve synapses may be a main factor of mechanisms of the influence of pulse magnetic fields on memory ability of rats.

Objective To study the effect of different attention states on auditory ERP and EEG power in normal subjects. Methods In three different states such as passive attention,active attention with target counting and active attention without target counting,EEG were recorded using oddball paradigm in 8 normal subjects while the test tones were presented;Then the peak-peak amplitude and latency of ERP were evaluated and the EEG power spectra were observed. Results The condition of active attention with target counting resulted in the smallest peak-peak amplitude of P 2-N 1 and the largest one of P 3-N 2,and it led to the increment of EEG power at the frequency of 10Hz,while the latencies did not differ among the three different attention states. Conclusion Reduced P 2-N 1 amplitude and increased P 3-N 2 amplitude reflected the allocation changes of attention resource in different states,and increased EEG power reflected more energy consumption in the process of recognition and memory,but the latency was relatively stable and not affected significantly by subject's attention condition.

Objective To investigate the effect and safety of photodynamic therapy (PDT) with topical aminolevulinic acid (ALA) in moderate to severe acne. Methods Seventy patients with moderate to severe acne were randomly divided into two groups, one group was treated with topical ALA-PDT for 1-3 sessions with an interval of 2 weeks, the other group received oral isotretinoin 10 mg twice a day for 6 weeks. Patients were evaluated for efficacy on week 2, 4 and 6 after the initial treatment. A 3-month follow up was performed to monitor adverse events following the end treatment. Results The total effective rate was 97.1% in ALA-PDT group after 1-3 sessions of treatment, 80.0% in the control group on week 6, and the difference was significant between the two groups (P<0.05). Acne lesions tended to recur more slightly with a longer remission period in ALA-PDT group than in the control group. A temporary and local pigmentation was observed in some patients treated with ALA-PDT, but no scar was noticed. Conclusion Topical ALA-PDT is a simple and effective treatment option for moderate to severe acne with mild side effects.

Objective To investigate the effects of 5-aminolaevulinic acid-photodynamic therapy (ALA-PDT) on precancerous changes and carcinoma of the skin in situ. Methods Fifteen patients with actinic keratosis, 3 patients with erythroplasia of Queyrat and 8 patients with Bowen′s disease were given topical ALA followed by PDT. Results The clearance was achieved in 17 lesions of 15 patients with actinic keratosis, 2 patients with erythroplasia of Queyrat and 7 patients with Bowen′s disease by topical ALA-PDT. The recurrence rates were 13.33%, 0 and 14.28% for actinic keratosis, erythroplasia of Queyrat and Bowen′s disease, respectively. Conclusions Topical ALA-PDT is a simple, effective and new treatment with lower recurrent rates, no scar formation and excellent cosmetic results for precancerous changes and carcinoma in situ of the skin, especially for the large and multifocal lesions located on the face and external genitalia.

Objective To investigate the optimal concentration and incubation time of 5-aminole-vulinic acid (ALA) in photodynamic therapy of acne vulgaris. Methods Thirty patients with facial acne vulgaris were equally divided into two groups. In group 1, ALA (10%)cream was applied to acne lesions and protoporphyrin Ⅸ (PpⅨ) fluorescence was examined visually and spectroscopically at 1, 2, 3, 4 and 5 hours. In group 2, ALA cream of 3%, 5% and 10% was applied to lesions in the right cheek, left cheek, and forehead, respectively, of the same patient and incubated for 3 hours followed by photodynamie diagnosis and quantification of fluorescence intensity; clinical outcome and side effects were analyzed. Results Strong brick red PpⅨ fluorescence was observed in inflammatory papules, pustules, and cysts alter applica-tion of 10% ALA cream and irradiation with excitation light. The relative intensity of Ppix fluorescence was 1.3, 4.3, 5.1 and 5.8 in comedones, inflammatory papules, pustules and cysts, respectively, and it increased with the severity of lesions. A higher intensity of PpⅨ fluorescence was noted in patients with longer incu-bation period (3, 4 or 5 hours) compared with those with shorter incubation period (1 or 2 hours), and the difference was significant (P < 0.05). However, there was no significant difference in PpⅨ fluorescence intensity among lesions receiving ALA of different concentrations (P > 0.05). The overall clearance rate was 73% (11/15) after two courses of ALA-photodynamic therapy (PDT) in group 2. Side effects mainly included mild to moderate erythema, swelling and little exudation (occasionally). A transient pigmentation was observed in 2 patients. Neither ulceration nor scarring was noted. Conclusions ALA-PDT is suitable for the manage-ment of acne vulgaris mainly characterized by inflammatory papules, pustules and cysts. The results strongly suggest that 3% and 3 hours are the optimal concentration and incubation time of ALA in PDT of acne vulgaris.

Objective To evaluate the usefulness of protoporphyrin Ⅸ (PpIX) fluorescence diagnosis after topical application of 5-aminolevulinic acid (ALA) in human papillomavirus (HPV) related diseases.Methods Photodynamic diagnosis (PDD) was conducted in 36 patients clinically diagnosed as genital condylomata acuminata. PpIX fluorescence was observed 2 hours following the application of 5-aminole-vulinic acid 20% cream on the lesions and subclinical lesions of these patients. Biopsy samples were resected from the lesions, subclinical lesions, and normal skin area (0.5 cm and 2 cm around the lesions) of the patients,and subjected to histopathological examination and microarray analysis for HPV DNA. Acetowhitening test was also performed at the four skin areas. Results Of the 36 patients, 30 were diagnosed as condylomata acuminata, 5 as bowenoid papulosis, and 1 as keratosis seborrheica by histopathological examination.Brick-red fluorescence of PpIX was observed in both lesions and subclinical lesions of all patients with condylomata acuminata and those with bowenoid papulosis, in subclinical lesions of 28 patients, at the area 0.5 cm around the lesions of 17 patients, and at the area 2 cm around the lesions of 5 patients. Acetowhitening and HPV DNA were also positive in lesions and subclinical lesions of patients with condylomata acuminata and those with bowenoid papulosis. Mucosa, inflammatory infiltration area and erosion tissue were prone to develop nonspecific PpIX fluorescence. Conclusions ALA-PpIX-mediated PDD can be used for the diag-nosis of clinical and subclinical HPV infection, as well as 'the location of latent HPV infection, however, it'snot recommended to be used in mucosa, inflammatory infiltration area or erosion tissue.

Objective To investigate the value of interventional therapy for nephrorrhagia after mini-invasive percutaneous nephrolithotomy(MPCNL).Methods From February 2007 to December 2008,16 cases with nephrorrhagia after MPCNL underwent interventional therapy,of them,14 cases treated with super-selective embolization,one case treated by kindey arterial embolization and one case with renal subcapsular bleeding treated by reptilase intra-arterial infusion.Results In 16 cases,15 cases were successfully treated by embolization.Conclusion Interventional therapy is the first choice method for treating nephrorrhagia after MPCNL.

Objective To investigate the efficacy and safety of 5-aminolaevulinic acid-photodynamic therapy (ALA-PDT) in cervical condyloma acuminatum. Methods Forty-five patients with cervical condyloma acuminatum topically applied 10% ALA thermal gel followed by PDT. The treatment was repeated 14 days later if the lesion was not completely removed. Totally, 1 - 4 treatment sessions were given. Thirty-five patients with cervical condyloma acuminatum who received CO2 laser treatment served as the control. All patients were followed up for 12 weeks. Results Complete remission was achieved in 97.8% (44/45) of patients with cervical condyloma acuminatum treated by ALA-PDT, and among the 44 cured patients, 3 were treated by 1 cycle of ALA-PDT, 6 by 2 cycles, 20 by 3 cycles, and 15 by 4 cycles. The lesions of condyloma acuminatum were removed after 1 session of CO2 laser treatment in 30 patients, and after repeated treatments in 5 patients, with the complete remission rate being 100% (35/35). The overall recurrence rate calculated for the whole followup period in patients treated with ALA-PDT was significantly lower than that in patients treated with CO2 laser [6.8% (3/44) vs 31.4% (11/35), x2 = 6.497, P ＜ 0.05]. However, no significant difference in complete remission rate was found between the two groups (P ＞ 0.05). Almost all the patients in ALA-PDT group presented with pain of bythus during illumination, but no severe side effects or scar formation was observed. In patients treated with CO2 laser, adverse reactions mainly included bleeding, erosion, shallow ulcer and even scar formation. Conclusions Topical ALA-PDT is effective and safe for the treatment and reduction in recurrence of condyloma acuminatum, and may serve as a therapeutic option for cervical condyloma acuminatum.