Objective To investigate the CT imaging manifestations of tumor-like proliferation of extramedullary hematopoiesis(EMH)in thalassemia(TM).Methods A retrospective analysis was conducted on the clinical data of 41 patients with tumor-like proliferation of EMH in TM.The CT imaging features of the patients were analyzed,including the location,lesion morphology,density,and degree of enhancement of the lesions.Results Lesions of varying sizes were identified on both sides of the thoracic vertebrae in all 41 cases,including 20 cases with lesions in the inner edge of the ribs and 1 case within the spinal epidural space.A total of 23 abdominal scans and 2 lumbar scans,lesions were found in the sacral region in 18 cases,primarily in the presacral area and sacral wings.Lesions adjacent to the thoracic paravertebral and in the sacral region were quasi-circular,while those on the ribs were quasi-circular or flat and mound-shaped,closely adhering to the inner edge of the ribs.Intraspinal epidural lesions were characterized by a longitudinal orientation,positioned adjacent to the posterior part of the thoracic spinal canal.Most lesions showed homogeneous moderate density.Bone erosion was observed in 14 rib lesions and 7 sacral region lesions,resulting in heterogeneous slightly high density shadow of the lesions.Small nodular high density shadow were identified in 4 cases,and small amounts of fatty density shadow were observed in 4 cases.20 cases showed mild-to-moderate enhancement on enhanced scan,and 11 cases showed"vascular traversal sign"in thoracic paravertebral lesions.Conclusion The CT manifestations of tumor-like proliferation of EMH in TM are characteristic.The combination of typical CT manifestations and medical history facilitates an accurate diagnosis.Indicators such as fat replacement,iron deposition nodules,bone erosion,and"vascular traversal sign"are valuable in the diagnosis of tumor-like proliferation of EMH.

Objective To investigate the CT imaging manifestations of tumor-like proliferation of extramedullary hematopoiesis(EMH)in thalassemia(TM).Methods A retrospective analysis was conducted on the clinical data of 41 patients with tumor-like proliferation of EMH in TM.The CT imaging features of the patients were analyzed,including the location,lesion morphology,density,and degree of enhancement of the lesions.Results Lesions of varying sizes were identified on both sides of the thoracic vertebrae in all 41 cases,including 20 cases with lesions in the inner edge of the ribs and 1 case within the spinal epidural space.A total of 23 abdominal scans and 2 lumbar scans,lesions were found in the sacral region in 18 cases,primarily in the presacral area and sacral wings.Lesions adjacent to the thoracic paravertebral and in the sacral region were quasi-circular,while those on the ribs were quasi-circular or flat and mound-shaped,closely adhering to the inner edge of the ribs.Intraspinal epidural lesions were characterized by a longitudinal orientation,positioned adjacent to the posterior part of the thoracic spinal canal.Most lesions showed homogeneous moderate density.Bone erosion was observed in 14 rib lesions and 7 sacral region lesions,resulting in heterogeneous slightly high density shadow of the lesions.Small nodular high density shadow were identified in 4 cases,and small amounts of fatty density shadow were observed in 4 cases.20 cases showed mild-to-moderate enhancement on enhanced scan,and 11 cases showed"vascular traversal sign"in thoracic paravertebral lesions.Conclusion The CT manifestations of tumor-like proliferation of EMH in TM are characteristic.The combination of typical CT manifestations and medical history facilitates an accurate diagnosis.Indicators such as fat replacement,iron deposition nodules,bone erosion,and"vascular traversal sign"are valuable in the diagnosis of tumor-like proliferation of EMH.

Objective To investigate the killing effect of herpes simplex virus thymidine kinase/gancyclovir (HSV-tk/GCV) suicide gene therapy system on retinoblastoma (Rb) cells and the mechanism of bystander effect. Methods By using liposome, pCMV/hytk-IREShrGFP plasmid was transferred into HXO-Rb44 cells. A fluorescence microscope was used to detect the transduction effeciency. The positive cell clones were selected by hygromycin and were named HXO-Rb44/tk. RT-PCR was resorted to demonstrate the sucessful transduction and transcription of hytk gene in the HXO-Rb44/tk cells. The morphologic features and growth patterns of HXO-Rb44/tk were compared with those of HXO-Rb44. Then MTT assay was used to determined the killing effect of GCV on HXO-Rb44/tk and the mixture of HXO-Rb44/tk and HXO-Rb44 in different ratios ("bystander effect"). The mechanism of bystander effect was studied by the experiment of supernatant shifting. Results The transduction effeciency was 20%. 530bp hytk gene strand was seen through HXO-Rb44/tk RT-PCR. There were no differences in the morphologic features or the growth patterns between HXO-Rb44/tk and HXO-Rb44. HXO-Rb44/tk was more sensitive to GCV than was HXO-Rb44. The cytotoxicity of HXO-Rb44/tk was dose and time dependent. An obvious "bystander effect" was seen even with low proportions of HXO-Rb44/tk, but this effect disappeared when transferring GCV containing supernatant of HSV-tk-positive cells to the negative cells. Conclusion The transfer of the HSV-tk gene into Rb cells followed by the administration of GCV could serve as a model for gene therapy for retinoblastoma, the "bystander effect" in HSV-tk/GCV-mediated gene therapy occurs by transfer of GCV metabolite from cell to cell through gap junction.

Objective　To study the occupational lung cancer among Yunnan tin miners during 1992-1997 by sputum cytology. Methods　The data of cases and occupational high-risk population for lung cancer among tin miners (Age≥40 years old and worked underground and／or at smeltery≥10 years) were analyzed. Results　There were 339 patients with lung cancer determined during six years, in which squamous cell carcinoma was 56.34％. The average incidence age was 65.78 years of age. The average positive rate to sputum cytology examination was 32.74％. The accuracy, specificity and sensitivity to sputum cytology examination were 99.35％, 99.81％ and 39.22％ respectively. The positive predictive value of sputum cytology examination was 62.01％, which was significantly higher than X-ray (33.05％)(P＜0.01). There were 48 recessive lung cancer cases and 12 suspicious recessive lung cancer cases found with sputum cytology during the six years. Conclusion　The sputum cytology examination is still one of the most effective methods for lung cancer screening among occupational high-risk population. The occupational high-risk population should be defined again (the tin miners' age≥50 years old and had worked underground and／or at smeltery≥10 years).