Imaging B lymphocytes in autoimmune inflammatory diseases.

B cells arise from stem cells precursor and develop through a tightly regulated and selective process that lead to the generation of different B cell populations such as transitional, mature, memory and plasma cells. These B cell subsets can be identified using flow cytometry by the expression of specific surface antigens. The growing knowledge of the pivotal role played by B cells in the development and progression of autoimmune diseases combined with the advances in monoclonal antibody technology, led in the last years to the generation of different biological agents targeting B cells. In this context, nuclear medicine can offer the possibility to use a panel of biologic radiopharmaceuticals for molecular imaging of inflammatory diseases. Radiopharmaceuticals bind to their targets with high affinity and specificity and have an excellent imaging diagnostic potential for the evaluation of disease activity, selection and monitoring of immune therapies. Several molecules have been radiolabelled for the imaging of T lymphocytes whereas, by now, the anti CD20 rituximab is the only biological therapy targeting B cells that demonstrated to be efficiently radiolabelled and used to detect inflammation in autoimmune patients.

Imaging B lymphocytes in autoimmune inflammatory diseases.

B cells arise from stem cells precursor and develop through a tightly regulated and selective process that lead to the generation of different B cell populations such as transitional, mature, memory and plasmacells. These B cell subsets can be identified using flow cytometry by the expression of specific surface antigens. The growing knowledge of the pivotal role played by B cells in the development and progression of autoimmune diseases combined with the advances in monoclonal antibody technology, led in the last years to the generation of different biological agents targeting B cells. In this context, nuclear medicine can offer the possibility to use a panel of biologic radiopharmaceuticals for molecular imaging of inflammatory diseases. Radiopharmaceuticals bind to their targets with high affinity and specificity and have an excellent imaging diagnostic potential for the evaluation of disease activity, selection and monitoring of immune therapies. Several molecules have been radiolabelled for the imaging of T lymphocytes whereas, by now, the anti CD20 Rituximab is the only biological therapy targeting B cells that demonstrated to be efficiently radiolabelled and used to detect inflammation in autoimmune patients.

High resolution mini-gammacamera and 99mTc [HMPAO] - leukocytes for diagnosis of infection and radioguided surgery in diabetic foot.

Discovery of osteitis may be delayed because of late appearance of X-ray signs in patients with diabetic foot. Scintigraphy with labelled leukocytes is able to detect flogosis but often misses bone involvement, due to inadequate resolution of Anger camera, the commonest detector used in nuclear medicine. Radioguided surgery and biopsy with high resolution scintigraphy (HRS) started to be studied since 2000: although this method had never been tested for planning and guiding diabetic foot surgery, in our opinion it can help early diagnosis and surgical treatment of diabetic foot. Five patients with diabetic foot and suspected infection were studied with standard 99mTc [HMPAO]-leukocyte scan. In the same patients 2 mm spatial resolution HRS was performed 24 hours after administration of labelled WBC, using our inch2 field-of-view portable mini-gammacamera. Operations were done just after the 24h scan and were guided with the portable high resolution device in the four patients who showed positive scan. Scintigraphy with Anger camera and HRS were positive in four patients. HRS showed a bar-shaped radioactivity corresponding to small phalanges, close to the main inter-digital hot spot. The presence of osteitis on phalanges that had been shown by HRS was confirmed at surgery, that was successfully driven with the high resolution mini-camera. In conclusion HRS is able to diagnose early osteitis of diabetic foot and to guide diabetic foot surgery.

An in vitro study to compare 99mTc-stannous colloids and 99mTc-HMPAO for labelling human leukocytes.

AIM: Aim of the present study was to compare in vitro the labelling efficiency (LE) and cell viability (TBE) of autologous leukocytes labelled with (99m)Tc-SnF(2) and (99m)Tc-HMPAO, and to evaluate the quantity and quality of spontaneously released (99m)Tc (SR) from labelled cells at several time points after labelling. METHODS: A total of 14 patients with different diseases and 18 normal subjects were included in this study. A blood sample was collected from each patient; purified autologous leukocytes were divided into 2 samples and labelled with (99m)Tc-SnF(2) and (99m)Tc-HMPAO. LE was evaluated at the end of labelling and TBE and SR were evaluated at 10 min and 1 h, 2 h and 4 h after labelling. RESULTS: LE of (99m)Tc-SnF(2)-WBC was higher than (99m)Tc-HMPAO-WBC (61.2+/-18.7% and 43.3+/-11.3; p<0.0001) and we found an inverse correlation between blood glucose and labelling efficiency for both methods (p=0.02). Minimal differences were also observed between 2 methods after 10 min and 1 h, as far as the cell viability is concerned. The percentage of radioactivity spontaneously released from (99m)Tc-SnF(2)-WBC was significantly higher compared to (99m)Tc-HMPAO-WBC at each time point. Radioactivity released from labelled cells was predominantly (99m)Tc-SnF(2) and (99m)Tc-HMPAO with few free (99m)Tc (<20%). CONCLUSION: Both radiopharmaceuticals are not toxic for WBC. Labelling with (99m)Tc-SnF(2) give a higher LE than with (99m)Tc-HMPAO; however, radiolabelled colloids are more released from labelled cells over a period of 4 h. While (99m)Tc-HMPAO is physiological excreted into gastrointestinal tract, (99m)Tc-SnF(2) can be re-uptaken in vivo by reticulo-endothelial cells of liver and spleen. These findings suggest that (99m)Tc-SnF(2)-WBC might be better than (99m)Tc-HMPAO-WBC for studying inflammatory bowel diseases.

[Radiology investment planning using the Break Even Point (BEP) method]. / Pianificazione di un investimento di radiologia mediante la metodica del Break Even Point (BEP).

The health care financing decision are becoming increasingly complex in all health care environments. As a managed care becomes a greater percentage of overall business, accurate financial planning and decision making will be key components of viable organization. Therefore, the priority for health care systems is to manage their costs at the same time as maintaining the relationships they have with patients, providers, payors, and communities in order to have long term success and short term survival. Principal wedge to value an investment is to define a planning in order to identify the activities, to attribute costs to the activities, to fix a full cost for every performances and to examine fixed costs and variable costs. This is the key to achieve a economic balance.

Chagas' disease screening in blood bank employing enzyme immunoassay.

Because of the high prevalence of Trypanosoma cruzi infection in Latin America, antibody screening in blood banks is mandatory in this area. This screening may also become a concern in the U.S.A. considering the high frequency of Latin American donors. The tests usually employed (indirect hemagglutination, direct agglutination, immunofluorescence and latex agglutination assays) involve subjective interpretation of results and do not fit the automated procedures requirements of large laboratories. Thus, an enzyme immunoassay was developed using a mixture of antigens purified from the membrane and the cytoplasm of the parasite. Serum of plasma could be used as sample, in a procedure involving 90 min total incubation time and 2 washing steps. Results could be interpreted either spectrophotometrically or by the naked eye. The method was used to test 661 samples from patients undergoing different stages of Chagas' disease, 120 patients suffering other parasitosis and 880 normal subjects. Results were compared with those obtained with the methods mentioned above. The proposed test showed better reproducibility, specificity and sensitivity than those of reference methods, plus an objective interpretation of results and suitability to automation.

Resistance to cymbidium ringspot tombusvirus infection in transgenic Nicotiana benthamiana plants expressing the virus coat protein gene.

Transgenic Nicotiana benthamiana plants expressing the coat protein gene of cymbidium ringspot virus (CyRSV) were tested for resistance against infection with CyRSV. Transgenic plants showed resistance to infection only when the purified virions concentration in the inoculum was as low as 0.05 micrograms/ml. No protection was observed in transgenic plants inoculated with virion concentrations of 0.5 and 5.0 micrograms/ml or when the inoculum was in vitro synthesized genomic RNA.

Monoclonal antibodies to beta subunit of choriogonadotropin: development and use in a sandwich ELISA pregnancy test.

Balb/c mice were immunized with beta subunit isolated and purified from crude human chorionic gonadotropin preparations. Spleen cells from the higher titered mouse were fused with Sp 2/0 myeloma cells. Four specific secreting hybridomas were obtained. Specificity, affinity, and suitability of secreted antibodies for use in enzyme immunoassays were studied. Ascites of the selected hybridoma was raised; the antibody was purified by protein A-affinity chromatography and coupled to horseradish peroxidase. This conjugate was employed in a simultaneous sandwich enzyme immunoassay on microtiter plates sensitized with goat polyclonal antibody to measure the hormone. The test has a sensitivity of 10 mlU/ml either on urine, serum, or plasma samples when read in a microplate reader. The results can also be evaluated by the naked eye, with a sensitivity of 20 mlU/ml. No cross reactivity was detected with other human gonadotropins.