The value of dual time point (18)F-FDG PET imaging for the differentiation between malignant and benign lesions.

AIM: To assess the clinical value of dual time point 2-[(18)F]-fluoro-2-deoxy-d-glucose positron emission tomography ((18)F-FDG PET) imaging for the differentiation between malignant and benign lesions. MATERIALS AND METHODS: Ninety-six patients (28 patients with primary lung cancer, 18 patients with digestive system carcinoma, 13 patients with other malignant tumours, and 37 patients with benign lesions) underwent FDG-PET/CT at two time points: examination 1 at 45-55 min and examination 2 at 160+/-24 (150-180) min after the intravenous injection of 233+/-52 (185-370)MBq (18)F-FDG. Reconstructed images were evaluated qualitatively and quantitatively. The maximum standardized uptake values (SUVmax) of the lesions were calculated for both time points. An increase was considered to have occurred if the SUVs at examination 2 had increased by >10% as compared with those at the examination 1. RESULTS: The lesions in 24 of 28 (86%) patients with primary lung cancer had an SUVmax > or = 2.5 at examination 1. Of these, SUVmax values increased in 23 patients, but had not changed in one patient, at examination 2. The lesions in the other four patients with primary lung tumour had SUVmax values between 1.5 and 2.5 at examination 1, which were considered as suspected positive, increased SUVmax values were observed in three of these patients at examination 2. The malignant lesions in 17 of 18 patients with digestive system carcinoma showed SUVmax values > or = 2.5 and only one patient had an SUVmax value < 1.5 at examination 1; all lesions showed an increase in SUVmax values at examination 2. In 13 patients with other malignant tumours, all lesions had SUVmax values > or = 2.5 at examination 1 and the SUVmax values were further increased at examination 2. Therefore, the malignant lesions in 54/59 (92%) of patients had SUVmax values > or = 2.5 at examination 1 and showed a further increase in SUVmax value at examination 2. Only 12 of 37 (32%) patients with benign lesions showed SUVmax values > or = 2.5 at examination 1 and nine patients with benign lesions had SUVmax values > or = 2.5 in examination 2. The sensitivity, specificity, accuracy, positive and negative predictive values for the early and delayed imaging were 91.5, 67.6, 82.3, 81.8, and 83.3%, and 98.3, 75.7, 89.6, 86.6, and 96.6%, respectively. CONCLUSION: The results of the present study provide further evidence that dual time point (18)F-FDG PET imaging is an important noninvasive method for the differentiation of malignant and nonmalignant lesions.

Somatostatin receptor scintigraphy in the follow-up of myasthenia gravis.

To evaluate the potential value of somatostatin receptor scintigraphy (SRS) using 111In-DTPA (diethylenetriaminepenta acetic acid)-D-Phe1-octreotide (111In-pentetreotide) in patients with recurring or persisting symptoms of myasthenia gravis (MG), 14 consecutive cases with such supplemental receptor imaging during neurological routine follow-up were retrospectively evaluated in this study. All 14 patients underwent SRS in addition to chest computed tomography (CT). Mean follow-up after imaging was 34 months. Eight patients had previous thymectomy, and three patients were referred to surgery after scintigraphy and chest CT. SRS was positive in one of the 14 patients with local recurrence of thymoma and pleural invasion, and negative in the remaining 13 patients. CT was positive for thymoma in three patients, inconclusive in four patients and negative in seven patients. In conclusion, while SRS may be able to detect thymoma lesions including metastases, it seems of limited value in patients with inconspicuous CT findings. Our initial experience fails to point out a benefit of SRS in the management of persisting or recurring MG (with regard to detection of thymic disorders) compared to CT. Whether SRS is useful for differentiating thymoma from non-neoplastic thymic disease may be investigated by larger series. A predominant proportion of patients with unsatisfactory treatment response, however, continue to suffer an unfavourable clinical course despite absent evidence for thymic pathology.

Model calculating annual mean atmospheric dispersion factor for coastal site of nuclear power plant.

This paper describes an atmospheric dispersion field experiment performed on the coastal site of nuclear power plant in the east part of China during 1995 to 1996. The three-dimension joint frequency are obtained by hourly observation of wind and temperature on a 100 m high tower; the frequency of the "event day of land and sea breezes" are given by observation of surface wind and land and sea breezes; the diffusion parameters are got from measurements of turbulent and wind tunnel simulation test. A new model calculating the annual mean atmospheric dispersion factor for coastal site of nuclear power plant is developed and established. This model considers not only the effect from mixing release and mixed layer but also the effect from the internal boundary layer and variation of diffusion parameters due to the distance from coast. The comparison between results obtained by the new model and current model shows that the ratio of annual mean atmospheric dispersion factor gained by the new model and the current one is about 2.0.

Quantitative analysis of the tomographic technetium-99m MIBI (99mTc-MIBI) myocardial bullseye display: application to diagnosis of coronary artery disease.

In this study, the 99mTc-MIBI myocardial bullseye display of 31 healthy persons and 34 patients with myocardial ischemia and 17 patients with myocardial infarction were analyzed quantitatively; and compared with the results of myocardial tomography analysis and qualitative bullseye analysis. The sensitivities of the three methods were 88.2%, 91.2% and 94.1% respectively (P > 0.05), and the specificities were 93.5%, 83.9% and 83.9% respectively (P < 0.05). On the other hand, the quantitative analysis obviously outperformed the other two methods in the detection of ischemic segments of myocardium near infarction zone (P < 0.01). The quantitative analysis of 99mTc-MIBI myocardial bullseye (quantitative bullseye) was an objective, specific and sensitive method for diagnosis of coronary artery disease.

[Dilatation of stricture of anastomosis after reconstruction of esophagus].

This article reports the experience of the esophagus dilating technique in the treatment of 658 cases of postoperative anastomotic stricture for esophageal cancer and cardiac cancer during the period from May 1983 to May 1993, being delated add up to 3240 times with total effective rate 96.5%, among them 61.6% of the cases less than five, 84.5% of the cases less than ten. Of them, 27 cases (4.1%) had postoperative complications, of which the main ones were esophagus perforation 8 cases (1.2%), hemorrhage of anastomotic stoma 4 cases (0.6%), mediastinitis 1 case (0.2%) and loca trauma 14 cases (2.1%). The operative indication, surgical technique and complication were discussed.

[Early coverage of deep partial-thickness burn wound with porcine dermal collagen membrane. An experimental study].

Collagen was extracted by pepsin digestion from porcine skin and collagen membrane was prepared by salt precipitation. Collagen membrane as a wound dressing was evaluated in a deep partial-thickness burn wounds in a rat model. Burn wound, 4 x 4 cm, were inflicted by exposing skin to 75 degrees C for 15 seconds followed by de-epithelization. Wound healing was assessed by plenimetry of epithelization on day 10 postwounding. Open wounds exhibited a re-epithelialization of 24% of wound area. Collagen membrane dressing significantly improved the healing rate to approximately 70% of wound area.

Porcine dermal collagen as a wound dressing for skin donor sites and deep partial skin thickness burns.

Collagen was extracted by pepsin digestion from porcine skin, and collagen membrane was prepared by salt precipitation. The porcine collagen membrane was evaluated as a burn wound dressing in deep partial skin thickness burn wounds in rats. Burn wounds, 4 x 4 cm, were inflicted by exposure of skin to 75 degrees C for 15 s followed by de-epithelialization. Wound healing was assessed by planimetry of epithelialization on day 10 after injury. Open wounds exhibited 24 per cent of wound area re-epithelialized. Collagen membrane dressing significantly improved the healing to 69 per cent of wound area (P < 0.0001). In a completely separate experiment, the porcine collagen membrane was applied as a wound dressing to the donor sites of burn patients, and its effect on wound healing was compared with that of a petroleum jelly gauze dressing. The donor sites covered with petroleum jelly gauze had re-epithelialized by an average of 14.5 days (ranging from 13 to 16 days) after wounding. The wounds dressed with collagen membrane demonstrated a significant increase in the healing rate. Complete re-epithelialization was observed by 10.3 days (ranging from 10 to 12 days) after wounding (P < 0.0001).

[Construction of a cDNA library of Schistosoma japonicum].

The template mRNA was extracted from Schistosoma japonicum. The first strand of cDNA was synthesized by AMV-reverse transcriptase. The second strand cDNA was first digested by RNase H to remove mRNA and was then synthesized by AMV-reverse transcriptase, T4-DNA polymerase. Sizing of cDNA was applied on a NACS column to remove small fragments of less than 1 kb. Homopolymeric tailing of vector (pUC18) was done with dGTP and DNA terminal transferase and tailing of the cDNA with dCTP was carried out under the same conditions. After annealing, the plasmids with cDNA were transformed into E. coli MC1061. The efficiency of cloning was about 10(4)/micrograms mRNA with 30% of the transformants having the inserts of cDNA (Figs. 1-2).

Scanning electron microscopic investigation of maxillary lateral incisors with a radicular lingual groove.

Fourteen human lateral incisors with a radicular lingual groove were observed under the scanning electron microscope to explore the communications between the groove and the pulp cavity. Observations showed that accessory foramina could be found not only in the groove, but also in the corresponding wall of the pulp cavity and a cross section. A complete lack of closure of the calcified tissues along the groove, allowing for direct connection of the pulp and the periodontium, was not found in these specimens. Therefore, it is suggested that accessory canals are the main way of communication between the pulp and the periodontium of the incisors with a radicular lingual groove. Because the accessory canals could be found either in the crown part or in the root part of the groove, infectious materials may get into the pulp cavity when there are pathologic conditions either through accessory foramina in the crown part or through accessory foramina exposed by localized periodontitis around the groove.

Seeding of arteriovenous prostheses with homologous endothelium. A preliminary report.

Endothelial cell seeding of expanded polytetrafluoroethylene (e-PTFE) arteriovenous prostheses was performed to compare seeding with homologous vs. autologous cells and to study the effect of homologous seeding with a larger vs. a smaller number of cells. Sixteen dogs were randomly assigned to four equal groups: I, control; II, light homologous seeded; III, heavy homologous seeded; and IV, autologous seeded. Bilateral femoral arteriovenous loop grafts were inserted in all. Efficiency of seeding was assessed by cell counts of instilled vs. retained cells. All grafts remained patent and were harvested approximately 8 weeks after implantation. Samples were evaluated grossly by scanning electron microscopy and light microscopy. There was a direct correlation between number of cells instilled and number retained for each graft; group III received and retained the largest number (p less than 0.001 and p less than 0.05, respectively). The amount of thrombus deposition on the lumen of all grafts was grossly the same. Endothelium was demonstrated in samples obtained from the midgraft of groups III and IV; in contrast no endothelium was seen in groups I and II. The percentage of endothelialized surface was not determined. No immunologic cellular reaction was detected in any of the samples. We conclude that in the animal laboratory it is possible to seed e-PTFE arteriovenous prostheses successfully with homologous cells and to improve the efficiency of seeding by implanting a larger number of cells obtained from an endothelial cell bank. The potential applications of this technique to the clinical field are discussed herein.

Coverage of full skin thickness burns with allograft inoculated with autogenous epithelial cells.

Since the supply of unburned autograft skin may be insufficient to cover very extensive burns, we have prepared allograft skin inoculated with a suspension of uncultured autogenous epithelial cells and grafted this material on to full skin thickness loss wounds. There was a satisfactory 'take' and permanent healing of this mixture of heterogeneous dermis and autogenous epidermis in two out of four patients. In this preliminary report we describe the clinical and histological observations which indicate that in the two patients with successful graft 'take' the epithelial cells proliferated and formed a continuous pale-coloured layer on top of the heterogeneous dermis between 30 and 40 days after application.

Hemodynamic and morphologic features of arteriovenous angioaccess loop grafts.

Bilateral femoral A-VLG (5 acute, 5 chronic) were implanted in 10 dogs (e-PTFE, 6 mm ID, 25 cm length). Acute studies included measurements of cardiac output (CO) and systemic vascular resistance (SVR). Blood pressure and pressure waveforms in the graft were obtained by retrograde catheterization and pull-back readings. Chronic dogs were sacrificed 8 wks postimplant; samples were obtained following a standardized protocol and studied by light microscopy (LM) and scanning electron microscopy (SEM). Hemodynamic data show a rise in CO, a decline in SVR and a high flow through each graft. Pull-back readings show a gradual drop in pressure and loss of pulsatility from the arterial to the venous side of the graft. LM studies show IH primarily in the proximal vein. SEM showed limited pannus ingrowth endothelium close to the anastomoses and otherwise a thrombus layer throughout the lumen. A-VLG are associated with high flow, pressure drop and loss of pulsatility. Proximal vein IH is a reproducible lesion. We conclude there is severe hemodynamic stress from disturbed flow and high flow velocity and it plays a critical role in the development of venous intimal hyperplasia in AV loop grafts.