Objective To evaluate the feasibility and establish the corresponding scanning plan through the clinical application of low-dose CT on diagnostic imaging for 111 AIDS patients with pnenmocystsis carinii pneumonia (PCP)and normal weight .Methods The thesis applied American GE(General Electric Company )FII double-row spiral CT scanner and the kV value is fixed to be 120 kV with the conventional dose (automatic mAs) and low-dose scanning applied respectively during the diagnosis .Meanwhile ,the low-dose scanning was carried out randomly in 50 mAs(50 mAs group) ,40 mAs(40 mAs group) and 30 mAs(30 mAs group) ,and then ,the iconographical imaging quality and radiation dose were analyzed ,the respective low-dose scanning plans was formulated at last .Results The high-quality film ratios for conventional close and 50 mAs group were 70 .3% and 62 .2% respectively ,and the good film ratios were 29 .7% and 37 .8% ,while no poor films occurred in both groups .The high-quality film ratios for conventional close and 40 mAs were 67 .6% and 56 .8% ,the the good film ratios were 32 .4% and 43 .2% and no poor films ,either .The high-quality film ratios for conventional close and 30 mAs were 70 .3% and 56 .8% ,the good were 29 .7% ,43 .2% and no poor films showed between both groups .From the results ,the consequential imaging films mainly show high and good quality ,all films meet the imaging diagnosis requirements and the difference are not statistically significant (P> 0 .05) .The radiation doses of conventional dose and low dose scanning (50 mAs ,40 mAs and 30 mAs groups) were 7 .6 mGy ,2 .6 mGy ,2 .1 mGy and 1 .5 mGy respectively , while the least radiation doses was for 30 mAs group and the corresponding dose is only 19 .8% of the original .The results from 111 patients applied conventional dose (automatic mAs) and low dose scanning all meet the imaging diagnosis requirements without any missed or erroneous diagnosis .Conclusion The chest low-dose CT scanning for AIDS patients with PCP and normal weight can fully meet the clinical diagnosis and treatment ,so it is practical and feasible .Meanwhile ,the conventional-dose scanning can be ap-plied at first and low-dose CT scanning later for reexamination to ensure the stability of image quality .For low-dose chest CT scan-ning ,the voltage fixed is 120 kV and the current 30 mAs .

AIM:To investigate the changes of connexin 43 (Cx43) via establishing a model of sympathomi-metic atrial fibrillation ( AF) .METHODS:The mongrels ( n=15) were randomly divided into control group , rapid atrial pacing (RAP) group and isoprenaline (ISO) perfusion+RAP group (ISO+RAP group).All mongrels’ hearts were taken out rapidly by median sternotomy to establish the cardiac model with Langendorff perfusion in vitro.The atrial effective re-fractory period ( AERP) and AF inducability were tested .The expression and distribution of tyrosine hydroxylase ( TH) were analyzed by immunohistochemistry .Total protein level of Cx 43 and phosphorylation of Cx 43 were determined by West-ern blot.The distribution of Cx43 were also observed by immunofluorescence staining .The cell apoptosis was analyzed by TUNEL staining.The generation of reactive oxygen species ( ROS) in the mitochondria was measured by fluorescence spec-trophotometry .RESULTS:No significant change of AERP was found between control group and RAP group , while that in ISO+RAP group was significantly decreased (P<0.05) and induced AF.Compared with control group, the expression of TH, apoptotic index and the generation of ROS increased gradually (P<0.05), while the content of Cx43 decreased grad-ually both in the total protein and the phosphorylation levels in RAP group and ISO +RAP group (P<0.05).The fluores-cence intensity of Cx43 was also attenuated and Cx43 were lateralized apparently in RAP group , while Cx43 were character-ized as punctate distribution in ISO +RAP group.CONCLUSION:Sympathetic nerves may activate autophagosome at in-tercalated discs and trigger cell apoptosis , resulting in remodeling and downregulation of Cx 43 via oxidative stress , thus having effects on mediating and maintaining AF .

PurposePulmonary tuberculosis (PTB) in the patients with AIDS often manifest as an atypical clinical manifestations, less positive rate in lab and various imaging features. This paper aims to compare the clinical and imaging manifestations of PTB in patients with AIDS and in patients with normal immunity may help us to improve the understanding of PTB in AIDS.Materials and MethodsThe clinical manifestations, the lab results and chest imaging data of 142 conifrmed PTB in patients with AIDS (observation group) and 150 conifrmed PTB in patients with normal immunity (control group) were retrospectively analyzed, the imaging review included the site, shape, density, property and the enhancement patterns of the enlarged lymph node in mediastinum and the status of pleura.ResultsThe incidences of fever, dyspnea, asthenia, anorexia, loss of weight, diarrhea, blurred vision, urinary irritation, oral leukoplakia, pruritus, rash, other pulmonary infections and extrapulmonary tuberculosis in observation group were signiifcantly higher than those in control group (χ2=4.173-68.542,P<0.05,P<0.01,P<0.001). The positive rates of tuberculosis in cough, hemoptysis, putum smear and sputum culture in observation group were signiifcantly lower than those in control group (χ2=30.376, 9.254 and 16.200, P<0.05). Imaging manifestations: observation group of type I, type II, type IV and type V patients were more than those in the control group (χ2=5.977, 8.621, 18.769 and 20.864, P<0.05). The lesions located at middle and lower lobes and involved more than three lobes in observation group than in control group at the same time (χ2=18.692 and 5.860,P<0.05, P<0.001), military nodules, enlarged lymph nodes in mediastinum and pleural effusion appeared more commonly in observation group than in control group (χ2=13.404, 34.704 and 19.469,P<0.001), while calcification, fibrosis and cavity were less in observation group compared to control group (χ2=6.539, 4.658 and 7.280,P<0.05,P<0.01,P<0.001). ConclusionPTB should be considered when AIDS patients present multiple symptoms in whole body, with pulmonary lesions located at middle and lower lobes & involved more than three lobes, military nodules, mediastinal enlarged lymph nodes and pleural effusion.

Objective To investigate the clinical and head CT imageological features features in 276 cases of intracranial tubercu‐losis .Methods The clinical and CT features in 276 inpatients with confirmed intracranial tuberculosis were analyzed .Results These 276 cases of intracranial tuberculosis all were complicated by pulmonary tuberculosis ,among them blood‐borne type accoun‐ted for 49 .6% ; young and middle‐aged cases were predominant (72 .5% ) ; the majority manifested by the symptoms of fever (70 .0% ) and headache(66 .2% ) ;the summer and autumn had the higher incidence rate ,which were 167 cases(80 .7% ) .The posi‐tive detection rate of head CT plain scanning was 63 .4% ,which of enhanced scanning was 98 .6% .Among them ,236(85 .5% ) cases were tuberculous meningitis lesions ,158 cases(57 .2% ) were tuberculous encephalitis ,144 cases (52 .2% ) were tuberculoma and 133 cases (48 .2% ) were tuberculous vasculitis .Conclusion The clinical menifestations of intracranial tuberculosis are atypical ,but the head CT plain scannig displays multiple abnormalities .Moreover ,the enhanced scanning increases the positive detection rate . The lesions of meninges ,brain vessels and brain parenchyma often occur together .Therefore ,the diagnosis basis should be combined with clinic ,laboratory tests and head CT ,especially the clinical application of head CT enhanced scanning should be paid attention to .

Objective: To explore the expression of myocardial levels of connexin 43(Cx43), Cx40 in experimental dog model of sympathomimetic atrial fibrillation (AF). Methods: 15 mongrels dogs were randomly divided into 3 groups: Control group, Rapid atrium pacing (RAP) group and RAP+isoprenaline (ISO) perfusion group. n=5 in each group. The hearts were taken to establish in vitro langendorff cardiac perfusion model. Atrial effective refractory period (AERP) and AF inducing rate were tested;intracellular expression and distribution of nerve growth factor (NGF) and tyrosine hydroxylase (TH) were examined by immunohistochemistry, total protein contents of Cx43 and Cx40 were measured by Western blot analysis, mitochondria morphology was observed by transmission electron microscope and mitochondria reactive oxygen species (ROS) generation was detected by fluorescent colorimetric method. Results: AERP was similar between Control group and RAP group (166±5.1) ms vs (160±3.2) ms which cannot induce AF; while it was shortened in RAP+ISO group (148±3.7) ms, P<0.05 which may successfully induce AF.Compared with Control group, mitochondria was slightly swollen in RAP group and the matrix was intact, while mitochondria was obviously swollen in RAP+ISO group and part of matrix was transparent; total protein contents of Cx43 and Cx40 were lower in both RAP group and RAP+ISO group, P<0.05; in addition, they were even lower in RAP+ISO group than RAP group, P<0.05. Compared with Control group and RAP group, RAP+ISO group had increased expression and distribution of NGF, TH and mitochondria ROS generation, P<0.05; NGF, TH and ROS in RAP group were higher than Control group, P<0.05. Conclusion: Sympathetic AF has been related to the contents and changes of myocardial levels of CX43 and Cx40; sympathetic nerve might trigger AF by oxidative stress induced down-regulation of myocardial CX43 and Cx40 in experimental dog model.

Objective:To investigate the features of chest computed tomography (CT) imaging and dynamic changes of severe corona virus disease 2019 (COVID-19).Methods:The clinical and CT data of 17 patients diagnosed with severe COVID-19 admitted to Chongqing Public Health Medical Center from January 24 to February 6, 2020 were collected. The first chest CT manifestations and the dynamic changes of imaging during treatment were retrospectively analyzed.Results:The first chest CT manifestations of the 17 patients showed that 16 cases presented with peripheral and subpleural distributions, and two cases presented with three lobes involved, one case with four lobes involved and 14 cases with five lobes involved, and 17 cases presented with ground-glass opacities, ten cases with consolidation, seven cases with subpleural line, nine cases with air bronchogram, three cases with thickened lobular septum, two cases with bronchiectasis, two cases with pleural effusion, three cases with lymphadenopathy with the short diameter of 1.0-1.2 cm.Among 16 patients who underwent repeated CT examination, the lesions of eight patients showed continuous improvement, and those of the other eight patients showed fluctuating changes.Conclusions:The CT findings of severe COVID-19 patients are mainly ground-glass opacities and consolidation, with the peripheral distribution. The range of lesions is wide, with five-lobe involvement mostly. Lymphadenopathy or pleural effusion is rare. Pynamic monitoring chest CT is useful for the evaluation for the therapeutic effects.

Objective: To investigate the features of chest CT imaging and dynamic changes of severe coronavirus disease 2019 (COVID-19). Methods: The clinical and computed tomography (CT) data of 17 patients diagnosed with severe COVID-19 admitted to Chongqing Public Health Medical Center from January 24 to February 6, 2020 were collected. The first chest CT manifestations and the dynamic changes of imaging during treatment were retrospectively analyzed. Results: The first chest CT manifestations of the 17 patients showed that 16 cases presented with peripheral and subpleural distributions, and 2 cases presented with 3 lobes involved, one case with 4 lobes involved and 14 cases with 5 lobes involved, and 17 cases presented with ground-glass opacities, ten cases with consolidation, seven cases with subpleural line, nine cases with air bronchogram, 3 cases with thickened lobular septum, two cases with bronchiectasis, two cases with pleural effusion, two cases with lymphadenopathy with the short diameter of 1.0-1.2cm. Among 16 patients who underwent repeated CT examination, the lesions of 8 patients showed continuous improvement, and those of the other 8 patients showed fluctuating changes. Conclusions The CT findings of severe COVID-19 patients are mainly ground-glass opacities and consolidation, with the peripheral distribution. The range of lesions is wide, with 5-lobe involvement mostly. Lymphadenopathy or pleural effusion is rare. Chest CT is useful for the evaluation for the therapeutic effects.