Objective:To investigate the denoising performance of different deep learning (DL) strategies on low-dose brain 18F-FDG PET images. Methods:This retrospective methodological study was conducted on brain PET/CT images of 50 patients (35 males, 15 females, age 20-87 years) who received 3.7MBq/kg 18F-FDG at the Fifth Affiliated Hospital of Sun Yat-sen University between May 2023 and January 2024. Full-dose PET data were acquired with 2min scan. CT scans were acquired before PET scanning. Low-dose PET sinograms were generated by down-sampling the full-dose list mode data to 1/2, 1/4, and 1/20 of full-dose count level. Both full-dose and low-dose sinograms were reconstructed with random, CT-based attenuation and scatter corrections using the three-dimensional (3D) ordered-subsets expectation maximization (OSEM) algorithm (2 iterations, 20 subsets). A total of 4 DL denoising methods were established: (1) 3D conditional generative adversarial networks (GAN) using only low-dose PET as input (GAN-1); (2) 3D attention-based GAN (AttGAN) with low-dose PET input (AttGAN-1); (3) 3D AttGAN with low-dose PET and CT inputs (AttGAN-2); (4) 3D AttGAN with frequency-separation using low-dose PET and CT inputs (AttGAN-FS-2). For AttGAN-FS-2, during the frequency division process, high- and low-frequency components were extracted from the PET reconstructed images via Fourier transform, then inversed Fourier transform, denoised separately, and finally combined to produce the final denoised images. The dataset was separated into training (70%), validation (10%) and testing (20%) sets using simple random sampling without replacement with a fixed random seed. A 5-fold cross-validation scheme was then applied to test all 50 patients. Performance was evaluated against full-dose PET using normalized mean square error (NMSE), structural similarity (SSIM), peak signal-to-noise ratio (PSNR), contrast-to-noise ratio (CNR), SUV mean and SUV max bias of selected brain ROIs. Wilcoxon signed rank test was used to analyze the differences between the denoising methods. Results:AttGAN-FS-2 showed the best performance among all dose levels, with statistical difference as compared by low-dose PET and GAN-1 denoised images for NMSE, SSIM, PSNR, and CNR ( Z values: 2.92-6.15, all P<0.005). NMSE, SSIM quantitative evaluation results (median) of each model at 1/20 dose were: GAN-1: 0.08, 0.87, AttGAN-1: 0.08, 0.88, AttGAN-2: 0.07, 0.89, AttGAN-FS-2: 0.06, 0.91, respectively ( Z values: 3.24-5.77, all P<0.005). Conclusion:The DL-based method combined with multiple strategies AttGAN-FS-2 shows improved denoising performance for low-dose brain PET images.

Objective:To investigate the denoising performance of different deep learning (DL) strategies on low-dose brain 18F-FDG PET images. Methods:This retrospective methodological study was conducted on brain PET/CT images of 50 patients (35 males, 15 females, age 20-87 years) who received 3.7MBq/kg 18F-FDG at the Fifth Affiliated Hospital of Sun Yat-sen University between May 2023 and January 2024. Full-dose PET data were acquired with 2min scan. CT scans were acquired before PET scanning. Low-dose PET sinograms were generated by down-sampling the full-dose list mode data to 1/2, 1/4, and 1/20 of full-dose count level. Both full-dose and low-dose sinograms were reconstructed with random, CT-based attenuation and scatter corrections using the three-dimensional (3D) ordered-subsets expectation maximization (OSEM) algorithm (2 iterations, 20 subsets). A total of 4 DL denoising methods were established: (1) 3D conditional generative adversarial networks (GAN) using only low-dose PET as input (GAN-1); (2) 3D attention-based GAN (AttGAN) with low-dose PET input (AttGAN-1); (3) 3D AttGAN with low-dose PET and CT inputs (AttGAN-2); (4) 3D AttGAN with frequency-separation using low-dose PET and CT inputs (AttGAN-FS-2). For AttGAN-FS-2, during the frequency division process, high- and low-frequency components were extracted from the PET reconstructed images via Fourier transform, then inversed Fourier transform, denoised separately, and finally combined to produce the final denoised images. The dataset was separated into training (70%), validation (10%) and testing (20%) sets using simple random sampling without replacement with a fixed random seed. A 5-fold cross-validation scheme was then applied to test all 50 patients. Performance was evaluated against full-dose PET using normalized mean square error (NMSE), structural similarity (SSIM), peak signal-to-noise ratio (PSNR), contrast-to-noise ratio (CNR), SUV mean and SUV max bias of selected brain ROIs. Wilcoxon signed rank test was used to analyze the differences between the denoising methods. Results:AttGAN-FS-2 showed the best performance among all dose levels, with statistical difference as compared by low-dose PET and GAN-1 denoised images for NMSE, SSIM, PSNR, and CNR ( Z values: 2.92-6.15, all P<0.005). NMSE, SSIM quantitative evaluation results (median) of each model at 1/20 dose were: GAN-1: 0.08, 0.87, AttGAN-1: 0.08, 0.88, AttGAN-2: 0.07, 0.89, AttGAN-FS-2: 0.06, 0.91, respectively ( Z values: 3.24-5.77, all P<0.005). Conclusion:The DL-based method combined with multiple strategies AttGAN-FS-2 shows improved denoising performance for low-dose brain PET images.

Objective To observe the effects of maternal high fat diet (MHFD) during pregnancy and lactation on intestinal barrier function in offspring mice.Methods C57BL/6 pregnant mice were divided into high fat diet (MHFD) group and normal diet group (MND) randomly and were given high fat diet and normal diet during pregnancy (3 weeks) and lactation (3 weeks) respectively.Both groups of offspring mice were naturally given and bodyweight of pups was monitored at birth and weekly.After weaning,the intestinal permeability of offspring mice was detected by fluorescein isothiocyanate conjugated-dextran method (FITC-D).Immunofluorescence was used to detect the expression of ZO-1 in intestinal tissues.HE staining was used to assess the villus length and crypt depth.The intestinal cell proliferation (expression of Ki-67) and Mucin 2 (MUC2) were assessed by immunohistochemistry.PAS staining was used to evaluate the goblet cells.The expression of inflammatory cytokines including IL-1β,IL-6,and TNF-α in intestinal tissue were measured by real-time PCR.Results At the age of 2 and 3 weeks,the offspring in MHFD group were significantly heavier than those in MND group.HE staining showed no obvious microscopic inflammation in both groups of 3 weeks old offspring mice,however,the relative expression levels of IL-1β (1.95±0.53 vs.1.13±0.15;t =3.65,P=0.005),IL-6 (1.40±0.71 vs.0.73±0.17;t=2.72,P=0.04),and TNF-α (1.63±0.53 vs.1.04±0.12;t=2.64,P=0.02) mRNA were significantly higher in the MHFD group.Compared with the 3 weeks old offspring mice in MND group,MHFD significantly increased the permeability of intestine and decreased the expression of ZO-1 in membrane.The number of Ki-67 positive cells (18.00±4.74 vs.24.60±4.17;t =3.31,P=0.004) in each villus,goblet cells (14.70±2.91 vs.28.10±4.95;t =7.38,P＜0.001) and MUC2 positive cells (20.60± 3.13 vs.30.00±3.33;t=6.50,P＜0.001) in each crypt were significantly lower than those in MND group.Conclusion Maternal high fat diet in early life of offspring mice can induce intestinal low grade inflammation and lead to the disruption of intestinal mucosal barrier in offspring mice,which may be involved in the progeny diseases.

Objective To explore the effect of tea polyphenols on the growth of human papillomavirus 16 (HPV16) subgenes-immortalized human cervical epithelial cells (H8 cells).Methods Cultured H8 cells were divided into 5 groups to be treated with 0 (control group),6.25,12.5,25 and 50 mg/L tea polyphenols respectively for 24,36,and 48 hours,and then cell counting kit-8 (CCK8)assay was performed to detect cell proliferation.After 24 hours of incubation,flow cytometry was conducted to detect cell apoptosis and cell cycle,and fluorescence microscopy to observe the morphology of apoptotic cells.Results After incubation with tea polyphenols at different concentrations for 24,36 and 48 hours,the proliferation of H8 cells was inhibited,and 12.5 mg/L tea polyphenols could inhibit the relative growth rate of H8 cells in a time-dependent manner.Flow cytometry showed that there was a significant difference in cell apoptosis rate among the 6.25-,12.5-,25-,50-mg/L tea polyphenols groups and the control group (52.62％ ± 0.62％,52.22％ ± 0.72％,42.52％ ± 0.90％,45.96％ ± 2.11％,29.96％ ± 0.70％ respectively,F =272.0,P ＜ 0.05).Moreover,all the tea polyphenol groups showed significantly increased cell apoptosis rate compared with the control group (all P ＜ 0.05).Fluorescence microscopy showed karyopyknosis,nuclear fragmentation and other typical apoptotic morphological changes in H8 cells in tea polyphenols groups.There were significant differences in the percentage of cells in G1,G2 phase and cell proliferation index among the 5 groups (all P ＜ 0.05).Compared with the control group,the 6.25-,12.5-,25-mg/L tea polyphenols groups showed significantly increased percentage of cells in G1 phase (55.96％ ± 0.72％,54.12％ ± 3.20％,65.30％ ± 1.51％ respectively,all P ＜ 0.05),but significantly decreased percentage of cells in G2 phase (3.17 ± 1.82％,4.94 ± 1.46％,4.65 ± 4.26％ respectively,all P ＜ 0.05) and lower cell proliferation index(0.44 ± 0.01,0.46 ± 0.02,0.36 ± 0.01 respectively,all P ＜ 0.05).Conclusion Tea polyphenols can inhibit the proliferation of H8 cells,induce cell apoptosis,and block cell cycle progression.

Objective To investigate the drug-resistance of Staphylococcus aureus induced by erythromycin in vitro and its changes in growth and susceptibility of antibiotics.Methods Erythromycin in vitro induction was conducted with the S.au-reus reference strain ATCC25923 on the serial of erythromycin agar plates.The growth of S.aureus,and the susceptibility a-gainst other antibiotics was compared after induced to the parent strain.Results Resistance to erythromycin was successful-ly,and themaximum MIC was over 256 mg/L.The Erythromycin-resistant S.aureus grew much slower than the susceptible parent,and the strains didn’t have cross-resistance to other antibiotics.Conclusion S.aureus could be induced resistance in vitro by erythromycin,and this resistance inherited stably.Some phenotype and biochemical characteristic features of the strain were changed after induced.

Objective To investigate the application value of 16S rDNA-based detection technique in the rapid screening for and confirmation of gonococcemia. Methods A 41-year-old male patient was hospitalized for recurrent regular fever and chills for 1 month. Several days before the admission, he developed urgent micturition, frequent micturition and pain in urination, anemia with emaciation appearance, slightly pale-looking skin and mucous membranes. No petechia, skin eruption or superficial lymphadenectasis was observed, but routine blood test and urine test results were abnormal. No abnormality was found in stool test or hepatic and renal function. DNA was extracted from the blood of the patient and subjected to PCR for the amplification of 16S rDNA followed by sequence analysis and homology analysis. At the same time, bacterial culture of blood and drug sensitivity test for the bacterial isolate were performed. Results Homology analysis indicated that the amplicon sequence was consistent with the known sequence of 16S rDNA of Neisseria gonorrhoeae in GeneBank, which agreed well with the culture result of peripheral blood. Conclusion The detection of 16s rDNA with PCR from peripheral blood is highly efficient, specific, sensitive, rapid and accurate for the screening for and confirmation of gonococcemia.

Objective To study the influence of sunscreens with different efficacy on delayed type hypersensitivity (DTH) and their immunoprotective effect in mice.Methods A cohort of mice were randomly divided into 5 groups with 10 mice in each group:group 1 as the positive control without irradiation,group 2 receiving solar-simulated radiation (SSR) only,group 3 receiving SSR and protected by sunscreen l with sun protection factor 15(SPF15)and persistent pigment darkening(PPD)12,group 4 receiving SSR and protected by sunscreen 2 with SPF 50 and PPD 28,and group 5 as the negative contml receiving SSR only.SSR was carried out on the back of mice with the UVA dose being 1.4 J/cm2 and UVB dose being 100 mJ/cm2 for 10 days.After a 5-day irradiation,the groups 1 to 4 were immunized by intraperitoneal injection with 100 μl(107 cells/ml) of Candida albicans suspension.On the 10th day both sides of the posterior foot pad were measured;then the foot pads were injected with additional 50 μl of the Candida albicans suspension.Twenty-four hours after the injection,the thickness of each foot pad was measured,and immunosuppression rate was calculated.Finally,the mice were sacrificed and skin samples were obtained from the back of these mice followed by the examination of CDla, CD80 and CD86 expression by Western blot.Resets The thickness of edema in foot pads was 0.41±0.38 mm,0.21±0.23 mm and 0.30 ± 0.25 mm in group 1,3 and 4,respectively,significantly higher than in group 5 and 2(0.04±0.03 mm,0.14±0.12 mm,respectively,all P<0.05),while no significant difference was observed between the group 3 and 4(P>0.05).Significant differences were observed in the immunosuppression rate between group 2,3 and 4(73.0%±11.3%,54.1%±6.4%,29.7%±7.5%,respectively,all P<0.01).Western blot revealed a significant increment in the expression of CDla protein in group 1 compared with group 2 as well as in the expression of CD86 protein in group 1 and group 3 compamd with group 2 and group 5(all P<0.05),but no statistical difference was observed between the other groups in the expression level of CDla,CD80 or CD86(P>0.05).Conclusions The exposure to sub-erythema dose of UV can induce DTH,and sunscreens have an immunoprotective effect in this process.Epidermal Langerhans cells are not essential for UV-induced immunosuppression.

Objective To characterize the prevalence and occurrence of respiratory viruses in chil-dren in Southern China. Methods Respiratory virus were identified from nasopharyngeal aspirates and throat swabs collected from children with bronchiolitis, bronchopneumonia and asthmatic bronchitis who visi-ted the Pediatrics of Affiliated Hospital to Shantou University, Shenzhen Fourth People's Hospital, Jieyang People's Hospital, during the period of June 2006 to June 2008. Respiratory virus was detected by multiplex PCR. Results Viruses were detected in 362 patients(52.77% ), among them, RSV infection was the most frequent, 31.22% of 113 patients. RHV was found in 16.85% (61 patients), IVA in 14.36% (52 pa-tients), ADV in 9.67% (35 patients), PIV in 16. 02% (58 patients), hBOV in 6. 08% (22 patients), hMPV in 4.97% ( 18 patients) and IVB in 0. 83% (3 patients). Conclusion The data indicate that RSV, RHV and IVA is an important etiological agent for respiratory infections in children during the survey period. RSV, IVA combined other virus are the most virus for combined infection, and the manages are worked out by the doctor for the diagnosis and treatment depended on the detected results of the pathogen.