Neocytoapheresis in the treatment of polycythemia vera

In absence of thrombocytosis, periodic bloodlettings represent the elective therapy of polycythemia vera. In the present study we tested if neocytoapheresis, a method able to remove large quantities of younger, and then bigger red cells could represent an alternative therapeutic choice in these patients. We found that the employment of neocytoapheresis produced a remarkable delay in the time of procedures with a mean interval of 100 +/- 55 days. The mean value of hematocrit before neocytopheresis is resulted statistically different in comparison with the hematocrit after the procedure (p = 0.0001). The reticulocyte count is resulted higher in apheresis product in comparison with the blood control measured before procedure (p = 0.0001). In the same way, the mean corpuscular volume in the collection bags was higher than the volume measured before neocytoapheresis (p = 0.0095). We did not find any variation about the mean values of white blood cells and platelets before and after neocytoapheresis in the patients examined. These preliminary data seem to underline a better withdrawal of big size cells by this technique suggesting the efficacy of neocytoapheresis in the treatment of polycythemia vera.     

Silicon heterojunction solar cell: a new buffer Layer concept with low-temperature epitaxial silicon

Amorphous silicon/crystalline silicon heterojunction solar cells, deposited by the plasma-enhanced chemical vapor deposition (PECVD) technique, have been fabricated using different technologies to passivate defects at the heterointerface: without treatment, the insertion of a thin intrinsic amorphous layer or that of a thin intrinsic epitaxial layer. The open circuit voltage of heterojunction solar cells fabricated including an intrinsic amorphous buffer layer is strangely lower than in devices with no buffer layer. The structure of the amorphous buffer layer is investigated by high resolution transmission electron microscope observations. As an alternative to amorphous silicon, the insertion of a fully epitaxial silicon layer, deposited at low temperature with conventional PECVD technique in a hydrogen-silane gas mixture, was tested. Using the amorphous silicon/crystalline silicon (p a-Si/i epi-Si/n c-Si) heterojunction structure in solar cells, a 13.5% efficiency and a 605-mV open circuit voltage were achieved on flat Czochralski silicon substrates. These results demonstrate that epitaxial silicon can be successfully used to passivate interface defects, allowing for an open circuit voltage gain of more than 50 mV compared to cells with no buffer layer. In this paper, the actual structure of the amorphous silicon buffer layer used in heterojunction solar cells is discussed. We make the hypothesis that this buffer layer, commonly considered amorphous, is actually epitaxial.     

Thin-film solar cells on commercial ceramic tiles

Amorphous silicon solar cells were deposited on porcelain stoneware tiles in order to develop a fully integrated PV building element. In a previous work we demonstrated the feasibility of adopting porcelain stoneware tiles as thin-film solar cell substrates and we fabricated solar cells on “industrial-level” ceramic substrates showing more than 4% efficiency. In this study we focus our attention on larger area devices deposited on tiles. As the active area increases additional problems arise from the surface of the substrate. In particular we find that short-circuit paths originate from the unfavorable properties of the substrate tiles (roughness, porosity, etc.) having dramatic consequences on the performance of larger area devices. With the assumption that spot-like regions, in which the back layer and the front layer are in electrical contact (local short-circuits), are present all over the device, we propose a new device structure to overcome the substrate drawbacks. A new contacts arrangement was designed in order to minimize the shunting effect of short-circuit paths. As a result an initial efficiency of 2.5% has been obtained using the new device structure for devices deposited on a PV mini-module tile.     

Influence of the sputtering system''s vacuum level on the properties of indium tin oxide films

The influence of the chamber residual pressure level in the radio frequency magnetron sputtering process on the electrical, optical and structural properties of indium thin oxide (ITO) is investigated. Several ITO films were deposited at various residual pressure levels on Corning glass using In₂O₃:SnO₂ target in argon atmosphere and without the addition of oxygen partial pressure. It is found that a very good vacuum is associated to metallic films and results in less transparent ITO films, with some powder formation on the surface. On the contrary highly transparent and conducting films are produced at a higher residual pressure. The best deposition conditions are addressed for ITO films as transparent conducting oxide layers in silicon heterojunction solar cells. Using the optimal vacuum level for ITO fabrication, a maximum short circuit current of 36.6 mA/cm² and a fill-factor of 0.78 are obtained for solar cells on textured substrates with a device conversion efficiency of 16.2%.     

Treatment of thrombotic thrombocytopenic purpura with high-dose immunoglobulins. Results in 17 patients. Italian Cooperative Group for TTP

BACKGROUND: The experimental observation that plasma from TTP patients sometimes exhibits a protein which can cause platelet agglutination, and that such agglutination can be inhibited in vitro by the use of IgG led some authors to treat plasma exchange-resistant TTP patients with high-dose IgG (HDIgG). METHODS: We report the results obtained with HDIgG treatment in 17 patients retrospectively examined by the Italian Cooperative Group for the study of TTP: 6 males and 11 females, mean age was 31.7 years for the women (range: 20-65) and 44.6 for the men (range: 26-66). In all cases HDIgG administration was combined with other treatment modalities. RESULTS: Of the 17 patients, 7 died from disease progression (41.1%), 2 achieved partial remission (11.7%) and the remaining 8 achieved complete remission (47%). Of the 10 cases (58.8%) with a positive response, only in 4 did the addition of HDIgG seem to produce significant improvement. All efforts made to characterize the subgroup of patients who responded to HDIgG and compare them with the non responders failed. CONCLUSIONS: Although our results do not unquestionably demonstrate the role of HDIgG in the treatment of TTP, they suggest a possible role for HDIgG in the treatment of those rare plasma exchange-resistant TTP cases.     

Cryosupernatant in thrombotic thrombocytopenic purpura (TTP): is it really useful?

PURPOSE: To identify proptosis as a manifesting sign of Weber-Christian disease (recurrent febrile nodular panniculitis). METHOD: Case report. A 61-year-old man had signs of right proptosis and orbital inflammation that resolved with oral corticosteroid therapy. Orbital inflammation later recurred with associated cutaneous nodules, myalgia, nausea, and malaise. RESULTS: Rheumatologic evaluation and subcutaneous nodule biopsy led to the diagnosis of Weber-Christian disease. The patient required systemic immunosuppressive agents to control the disease. CONCLUSION: This case shows the rare finding of proptosis as the manifesting sign of Weber-Christian disease.     

VACOP-B versus VACOP-B plus autologous bone marrow transplantation for advanced diffuse non-Hodgkin's lymphoma: results of a prospective randomized trial by the non-Hodgkin's Lymphoma Cooperative Study Group

PURPOSE: The aim of this multicenter randomized study was to compare conventional therapy with conventional plus high-dose therapy (HDT) and autologous bone marrow transplantation (ABMT) as front-line treatment for poor-prognosis non-Hodgkin's lymphoma (NHL). PATIENTS AND METHODS: Between October 1991 and June 1995, 124 patients, aged 15 to 60 years, with diffuse intermediate- to high-grade NHL (Working Formulation criteria), stages II bulky (> or = 10 cm), III, or IV were enrolled. Sixty-one patients were randomized to receive etoposide, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin (VACOP-B) for 12 weeks and cisplatin, cytarabine, and dexamethasone (DHAP) as a salvage regimen (arm A), and 63 to receive VACOP-B for 12 weeks plus HDT and ABMT (Arm B). RESULTS: There was no significant difference in terms of complete remissions (CRS) in the two groups: 75% in arm A, and 73% in arm B. The median follow-up observation time was 42 months. The 6-year survival probability was 65% in both arms. There was no difference in disease-free survival (DFS) or progression-free survival (PFS) between the two groups. DFS was 60% and 80% (P = .1) and PFS was 48% and 60% (P = .4) for arms A and B, respectively. Procedure feasibility was the major problem. In arm B, 29% of enrolled patients did not undergo HDT and ABMT. A statistical improvement in terms of DFS (P = .008) and a favorable trend in terms of PFS (P = .08) for intermediate-/high- plus high-risk group patients assigned to HDT and ABMT was observed. CONCLUSION: In this study, conventional chemotherapy followed by HDT and ABMT as front-line therapy seems no more successful than conventional treatment in terms of overall results. However, our results suggest that controlled studies of HDT plus ABMT should be proposed for higher risk patients.     

High prevalence of hepatitis C virus infection in patients with non-Hodgkin''s lymphoma at the onset. Preliminary results of an Italian multicenter study]

Inhibitors of carbonic anhydrase activity have been found to increase blood and organ PCO2 and to increase blood flow (BF) in individual organs. To determine whether carbonic anhydrase inhibition coordinately induces an increase in BF in several organs, we assayed the effect of the carbonic anhydrase inhibitor, acetazolamide (AZ), on BF in rabbit organs using the colored microsphere (CM) assay. Eight female white rabbits were anesthetized with ketamine and urethane, and administered three sequential doses of 4 mg/kg AZ. After each dose, the rabbits were injected with 9 x 10(5) CMs of different colors, and arterial blood was collected. We found that AZ had no effect on blood pressure, body temperature, hemoglobin concentration, or PaCO2. In contrast, 12 mg/kg AZ significantly increased PaO2 and significantly decreased base excess. When we measured organ BF, we observed, in response to 12 mg/kg AZ, an 82% increase in brain BF and a 55% increase in kidney BF, but no change in BF of the liver, stomach wall, or abdominal muscle. These findings suggest that the inhibition of carbonic anhydrase activity by AZ, which decreases the rate of CO2 conversion to HCO3-, causes the retention of CO2 in tissues and organs, and thus increases BF in specific organs. Administration of carbonic anhydrase inhibitors, such as AZ, may increase BF to the brain and kidney without reducing PaO2, thereby increasing the supply of oxygen in conditions involving hypoxia such as ischemia and shock.     

Role of front contact work function on amorphous silicon/crystalline silicon heterojunction solar cell performance

We investigated with numerical simulations the effects that a transparent conductive oxide front contact (TCO) can have on amorphous silicon/crystalline silicon heterojunction solar cells. We found that, due to the extremely thin emitter layer used in this kind of device, the built-in potential available cannot be merely defined by the difference between the work function of the emitter and the base, but it depends on TCO work function as well. As a consequence, because of the correlation between built-in potential and open circuit voltage, the TCO work function strongly affects the solar cell performance. Simulation results show that a higher work function leads to the best device efficiency.     

Factors affecting hemopoietic recovery after high-dose therapy and autologous peripheral blood progenitor cell transplantation: a single center experience

Major depression is one of the most common psychiatric problems complicating the treatment and prognosis of patients with active medical illness. Recognizing and treating major depressive conditions in this population can often be challenging, even for the most seasoned clinicians. This article reviews the medical and neurologic conditions that have been associated with the high prevalence rates of major depression. Highlights of the evaluation process that help confirm this suspected diagnosis are addressed, and management issues are discussed. Brief reviews of supportive psychotherapeutic tools that the clinician may find helpful are included, as well as current advances in pharmacologic interventions.