Background: Secondary pulmonary hypertension (PH) and cor pulmonale are the major clinical cardiovascular complications affecting prognosis in patients with chronic obstructive pulmonary disease (COPD). It is also known that endothelin-1 (ET-1) is a potent vasoconstrictor peptide produced by the pulmonary vascular endothelium, and ET-1 may be implicated in the pathogenesis of PH. Objectives: The purpose of this study was to investigate the presence of ET-1 in patients with COPD and to assess the correlation of ET-1 levels in the plasma and bronchoalveolar lavage (BAL) fluid (BALF) in COPD patients with or without PH. Methods: Twenty-two patients with COPD and 15 healthy controls were enrolled in the study. Peripheral venous blood samples were collected in all patients and controls. BAL was obtained in COPD patients, and ET-1 levels were measured by radioimmunoassay in all plasma and BALF samples. Results: Plasma ET-1 levels were 2.46 ± 0.55 and 1.70 ± 0.42 pmol/dl in patients with COPD and controls, respectively (p < 0.0001). Sixteen of the 22 patients with COPD (73%) had PH established by echocardiography. The ET-1 level in these patients amounted to 2.59 ± 0.50 pmol/dl, and it was 2.10 ± 0.54 pmol/dl in 6 patients with COPD without PH. In COPD patients with and without PH, BALF ET-1 levels were 0.19 ± 0.08 and 0.24 ± 0.01 pmol/dl, respectively (p > 0.05). Conclusions: These results suggest that ET-1 is detectable in both the peripheral blood and BALF of COPD patients, but the levels do not statistically differ between patients with and without PH.

Radiolabeled antibiotics are promising radiopharmaceuticals for the precise diagnosis and detection of infectious lesions. Doxycycline Hyclate (DOX) was chosen to investigate new (99m) Tc-labeled antibacterial agent. Ready to use freeze dry kits were formulated with optimum labeling conditions. Human serum stability, sterility, and pyrogenicity of kits were estimated, and gamma scintigraphy, in vivo biodistribution, and histopathological studies with bacterial infected rats were performed. DOX were successfully labeled by (99m) Tc with high radiochemical purity, and the labeled compound was stable in human serum. Kits were sterile, pyrogen-free, and stable up to 6 months. Static images depicted rapid distribution throughout the body and high uptake in bacterial infected thigh muscle. The uptake ratios of radiopharmaceuticals in infected thigh muscle were found above 2 up to 5 h. Five hours after injection, the rats were sacrificed, and biodistribution was determined. Samples of bacterial infected muscle, healthy muscle, blood, liver, spleen, lung, kidney, stomach, intestine, urine and heart were weighed, and the radioactivity was measured by using a gamma counter. The %ID/g of (99m) Tc-DOX was found 0.23 ± 0.06 for infected thigh muscle. According to the imaging, biodistribution, and histopathological studies, the promising characteristics of (99m) Tc-DOX make the new radiopharmaceutical valuable to examine for future studies.

Radioisotope synovectomy (RS) is defined as the intra-articular injection of radioisotopic agents with the aim of fibrosis on hypertrophic synovium in the target joint. The aim of this study was to investigate genotoxic effects on lymphocytes and malign transformation induced by Yttrium(90) (Y(90)) and Rhenium(186) (Re(186)) in children with haemophilia undergone RS. Forty haemophilia patients were enrolled. The mean age was 16.4 +/- 6.2 years (range: 8-40). Y(90) was used for knees, Re(186) was used for other joints. For safety, cytogenetic analysis was performed to determine potential chromosomal changes after RS procedure at three different time points as prior to procedure, 3rd day and 90th day. For the stimulation of chromosomal breakages, diepoxybutane was used (DEB test). Chromosomal breakages (CBs) were found in 23 patients (67.6%) prior to RS. We have found CBs additionally in nine of 11 patients who had no CBs prior to RS after 3 days of radioisotope exposure. At that time, the patients who had CBs were 29 (85.2%). At day 90, only 21 patients revealed (61.7%) CBs. The mean frequency of CBs slightly but not significantly increased in the 3rd day. However, there was a significant decreasing trend between 3rd and 90th days. Radioisotope synovectomy with Y(90) and Re(186) does not seem to induce the genotoxic effects significantly on peripheral blood lymphocytes. However, CBs even after one year in the re-evaluation of four patients, significant decrease in the number of CBs between the 3rd and 90th days and de novo CBs after exposure may be accepted as warning signals for young population. It should also be pointed out that families and patients be informed properly related with historical and potential dangers of radioisotopic agents.

Radioisotope synovectomy (RS) seems to be a safe procedure not causing a significant genotoxic effect on hemophilic patients, however, further studies including larger series of patients are needed to better understand the effects of RS on patients' health.

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