An innovative in vitro device providing continuous low doses of γ-rays mimicking exposure to the space environment: A dosimetric study.

Astronauts are exposed to microgravity and chronic irradiation but experimental conditions combining these two factors are difficult to reproduce on earth. We have created an experimental device able to combine chronic irradiation and altered gravity that may be used for cell cultures or plant models in a ground based facility. Irradiation was provided by thorium nitrate powder, conditioned so as to constitute a sealed source that could be placed in an incubator. Cell plates or plant seedlings could be placed in direct contact with the source or at various distances above it. Moreover, a random positioning machine (RPM) could be positioned on the source to simulate microgravity. The activity of the source was established using the Bateman formula. The spectrum of the source, calculated according to the natural decrease of radioactivity and the gamma spectrometry, showed very good adequacy. The experimental fluence was close to the theoretical fluence evaluation, attesting its uniform distribution. A Monte Carlo model of the irradiation device was processed by GATE code. Dosimetry was performed with radiophotoluminescent dosimeters exposed for one month at different locations (x and y axes) in various cell culture conditions. Using the RPM placed on the source, we reached a mean absorbed dose of gamma rays of (0.33 ± 0.17) mSv per day. In conclusion, we have elaborated an innovative device allowing chronic radiation exposure to be combined with altered gravity. Given the limited access to the International Space Station, this device could be useful to researchers interested in the field of space biology.

Use of fluorescent in-situ hybridisation in salivary gland cytology: A powerful diagnostic tool.

OBJECTIVE: Salivary gland cytology is challenging because it includes a diversity of lesions and a wide spectra of tumours. Recently, it has been reported that many types of salivary gland tumours have specific molecular diagnostic signatures that could be identified by fluorescent in-situ hybridisation (FISH). The aim of the present study was to demonstrate the feasibility and efficiency of FISH on routine cytological salivary gland smears. METHODS: FISH was conducted on 37 cytological salivary gland smears from 34 patients. According to the cytological diagnosis suspected, MECT1/MAML2 gene fusion and rearrangements of PLAG1, MYB, or ETV6 were analysed. The presence and percentages of cells that had gene rearrangements were evaluated. Results were compared with the histological surgical samples, available from 26 patients. RESULTS: The PLAG1 rearrangement was observed in 12/20 (60%) cases of pleomorphic adenoma. MECT1/MAML2 gene fusion was observed in 1:2 mucoepidermoid carcinomas but was not observed in five other tumours (two pleomorphic adenomas, one Warthin's tumour, one mammary analogue secretory carcinoma [MASC] and one cystic tumour). MYB rearrangement was observed in 4/4 adenoid cystic carcinomas. ETV6-gene splitting identified one MASC. CONCLUSION: Overall, FISH had a specificity of 100% and a sensitivity of 66.7%. When FISH and cytological analyses were combined, the overall sensitivity was increased to 93.3%. It can thus be concluded that when the FISH analysis is positive, the extent of surgery could be determined with confidence pre-operatively without needing a diagnosis from a frozen section.

Immunocytochemical staining for p53 and Ki-67 helps to characterise urothelial cells in urine cytology.

OBJECTIVE: The presence of atypical cells in urine cytology is unsatisfactory for both cytologists and clinicians. The objective of this study was to test whether p53 and Ki-67 immunostaining could improve urothelial carcinoma (UC) detection on urinary cytology. METHODS: A total of 196 urine samples were analysed, 142 from the bladder, 41 from the upper tract and 13 from ileal bladder replacement. Cytology results were expressed as normal (N) (n = 81), atypia cannot exclude low-grade UC (ALG) (n = 25), suspicious for high-grade UC (SHG) (n = 39) and high-grade UC (HG) (n = 51). Actual diagnoses were confirmed by histopathological analysis, cystoscopic examination or follow-up for at least 1 year. Immunocytochemistry performed on CytoSpin™ slides allowed the determination of the percentage of positive cells with p53 and Ki-67. RESULTS: The median percentage values [first to third quartile] of p53 and Ki-67 were 0 [0-5] and 0 [0-1] for N cytology, 5 [0-40] and 2 [1-10] for ALG, 10 [0-30] and 6 [3-25] for SHG, and 30 [10-80] and 20 [10-30] for HG, respectively. Statistically higher values were observed for both tests (P < 0.001) in positive cytologies (ALG, SHG and HG). The optimal cut-offs were 5% for p53 and 3% for Ki-67. The sensitivity and specificity for the detection of all UC were 86.4% and 76.7% for cytology alone, 81.3% and 93.2% for cytology and p53, 75.7% and 88% for cytology and Ki-67, and 68.9% and 97.5% for cytology, p53 and Ki-67, respectively. CONCLUSION: Using p53 and/or Ki-67 in addition to cytology increases the specificity without penalising the sensitivity.

Improvement of the cytological diagnostic accuracy of follicular thyroid lesions by the use of the Ki-67 proliferative index in addition to cytokeratin-19 and HBME-1 immunomarkers: a study of 61 cases of liquid-based FNA cytology with histological controls.

OBJECTIVES: To evaluate HBME-1, cytokeratin-19 (CK-19) and Ki-67 immunomarkers in order to increase the diagnostic accuracy of preoperative thyroid fine needle aspiration (FNA) cytology. METHODS: Immunocytochemistry against HBME-1, CK-19 and Ki-67 was performed on 123 thyroid FNAs processed by liquid-based cytology (LBC). Statistical analysis was carried out on 61 cases with histological control and sufficient material for one or more of the three markers. The Bethesda System was used for cytological diagnosis. RESULTS: Taking into account all the cytological categories, with a cut-off of 30% of positive cells, HBME-1 (n = 47) and CK-19 (n = 53) showed a sensitivity for malignancy of 66.7% (95% confidence interval, 53.2-80.1) and 90.5% (82.6-98.4) and a specificity of 90.6% (82.3-99) and 75% (63.3-86.7), respectively. For Ki-67 (n = 54) with a cut-off of 1% of positive cells, the sensitivity was 85.0% (75.5-94.5) and the specificity 70.6% (58.4-82.7). In the follicular neoplasm/suspicious for follicular neoplasm (FN/SFN) category (n = 37), which was the focus of the study, papillary thyroid carcinomas (PTCs) were less numerous (four cases, three of which were the follicular variant), the positivity of the three immunomarkers combined showed an overall accuracy of 91% (21/23). The mean percentage of Ki-67-positive cells was increased in malignant lesions, with the exception of follicular variant PTCs: 16% ± 15.6% in two follicular carcinomas, 4.8% ± 3.2% in 13 classical PTCs, 1% ± 1.2% in five follicular variant PTCs and 0.5% ± 1.9% in 34 non-malignant lesions. CONCLUSIONS: Immunocytochemistry using HBME-1, CK-19 and the Ki-67 proliferative index increased the diagnostic accuracy of FNA in the FN/SFN category of the Bethesda System, which may help to distinguish lesions in this category with a low or high risk of malignancy. Thus, clinical management would be improved.

Investigation of the significance of Oil Red O-positive macrophage excess in bronchoalveolar lavage fluid during HIV infection.

OBJECTIVE: To assess the significance of increased levels of Oil Red O-positive macrophages (ORO-PM) in bronchoalveolar lavage fluids (BALFs) from HIV-positive patients. METHODS: Cytological data for seventy BALF samples from 66 consecutive HIV-infected patients were analysed according to antiretroviral therapy regimen, presence of Pneumocystis jiroveci infection, blood CD4(+) T cell count, HIV-1 viral load and plasma lipid levels. Non-parametric tests were used to compare the values between groups. RESULTS: The percentages of ORO-PM were high in this group: 40% [6-80] (median [interquartile range]). They were positively correlated with the BALF total cell count, 21% [5-48.5] for <300 cells/mm(3) and 60% [26.5-80] for >300 cells/mm(3) (P<0.01) but inversely correlated with the percentage of BALF lymphocytes, 50% [20-80] for <15% lymphocytes and 11.5% [2-47] for ≥15% lymphocytes (P<0.01). Antiretroviral therapy with or without protease inhibitors, plasma lipid levels, HIV-1 viral load, blood CD4(+) T cell count or presence of a Pneumocystis jiroveci infection were not correlated with the ORO-PM status. CONCLUSION: Significantly increased numbers of ORO-PM were correlated with high total cell counts and low lymphocyte counts in BALF, irrespective of disease activity or treatment. Extended work on a larger series of patients needs to be conducted.

Cut-off values and significance of Oil Red O-positive cells in bronchoalveolar lavage fluid.

OBJECTIVE: To evaluate the percentage and predictive value of Oil Red O-positive macrophages (ORO-PM) to identify lipid-laden macrophages in bronchoalveolar lavage fluids (BALF) from patients with different pathologies. METHODS: The percentage and absolute numbers of ORO-PM were evaluated in 305 BALF. The patients were separated into ten groups: corticosteroid treatment (n = 18), amiodarone treatment (n = 8), interstitial fibrosis (n = 11), human immunodeficiency virus (HIV)-positive (n = 25), infectious pneumonia (n = 43), severe haematological disorder (n = 25), interstitial syndrome (n = 109), suspicion of cancer (n = 17), transplant recipients (n = 50) and controls (n = 43). The total and differential cell counts in BALF were recorded. The presence of specific pathogens was also noted. Parametric and non-parametric tests were used to compare the values between groups. Receiver-operating characteristics (ROC) curves were established in order to determine a cut-off value. RESULTS: The percentages of ORO-PM were (mean +/- standard deviation) 21.67 +/- 29.12 in the corticosteroid group, 10.00 +/- 12.49 in the amiodarone group, 19.45 +/- 20.72 in the interstitial fibrosis group, 47.80 +/- 30.46 in the HIV group, 19.72 +/- 26.26 in the infectious pneumonia group, 27.42 +/- 30.04 in the severe haematological disorder group, 25.18 +/- 30.63 in the interstitial syndrome group, 17.64 +/- 27.76 in the suspicion of cancer group, 22.50 +/- 27.27 in the transplanted recipients group and 2.63 +/- 3.48 in the control group. Significantly higher values were found in all groups when compared with the control group (P < 0.001). Only the HIV group showed higher numbers of ORO-PM when compared with the interstitial syndrome group (P < 0.01). According to ROC curves, > 6% ORO-PM was suggested as the positive cut-off value. CONCLUSION: Significantly increased numbers of ORO-PM were associated with various lung pathologies. However, the higher numbers observed in HIV patients require further investigations.

Effect of continuous irradiation with a very low dose of gamma rays on life span and the immune system in SJL mice prone to B-cell lymphoma.

Ionizing radiation has been shown to have dose- and dose-rate-dependent carcinogenic effects on the hematopoietic and lymphoreticular systems. We report here that continuous exposure to a low dose of gamma rays influences the course of spontaneous B-cell lymphoma in SJL mice. We studied the biological effects of 10 cGy year(-1) gamma rays on the life span of 560 4-week-old SJL/J female mice and on various parameters of the cell-mediated immune response. Life span was slightly prolonged. The mean survival was 397 days for controls and 417 days for irradiated mice that died with lymphoma (P = 0.34). In lymph nodes and spleen, lower percentages of CD4+ and CD8+ T cells were observed in irradiated mice before 32 weeks. Interestingly, the percentages of CD49+ NK cells were increased in the spleens of irradiated mice at 28 weeks (0.61 +/- 0.08% compared to 0.43 +/- 0.12% in controls, P = 0.01) and at 32 weeks (0.62 +/- 0.24% compared to 0.33 +/- 0.09%, P = 0.02), while NK cell activity remained unchanged in exposed mice. These results provide further support for the absence of harmful effects of a continuous very low dose of radiation on life span and incidence of lymphoma in SJL mice.