Enhanced surface registration techniques for patient positioning control in breast cancer radiotherapy

Experimental data, describing patient inter-fractional set-up errors in the clinical practice of breast radiotherapy, were exploited to simulate the performance in errors detection and correction of a constrained surface registration procedure, based on a hybrid configuration of control points (passive and laser). During 47 treatment sessions in three patients undergoing post-quadrantectomy radiotherapy, an opto-electronic localizer was used to acquire the three-dimensional coordinates of the hybrid control points, being two passive markers placed on selected skin landmarks on the sternum. Laser scanning technique was also applied for the acquisition of the 3-D surface model of the irradiated body area, which was used as reference for the automatic position correction procedure. A constrained surface registration algorithm was applied to estimate the rigid spatial transformation, describing the local errors affecting the control points. The improvement of the irradiation geometrical set-up, by correcting the patient position according to the estimated spatial transformation parameters, was simulated. Results showed that the proposed surface registration method allowed us to detect and significantly (Wilcoxon signed rank analysis) reduce the initial misalignments, which exhibited overall median and 75th percentile values equal to 4.26 mm and 5.76 mm. Simulated residual errors dropped down to median and 75th percentile values measuring 2.95 mm and 3.87 mm, respectively. These results confirmed the high potentiality of surface registration techniques for the opto-electronic automatic patient positioning control in breast cancer radiotherapy.     

Sertoli cell-induced adult rat islet beta-cell mitogenesis: causative pathways

We have previously observed that in vitro co-incubation of rat pre-pubertal Sertoli cells (SC), or their dialyzed/concentrated secretory products with homologous islets, resulted in significant stimulation of the islet beta-cell mitotic index. Aim of the present work was to assess both the specificity and nature of the mechanisms underlying this phenomenon. For this purpose, first we tested astrocytes (AA), separated and purified from the rat brain cortex, where they are known to release a number of growth factors and neurotrophic cytokines, for co-incubation with the islets. However, under the same experimental conditions used for SC, AA did not induce any changes in the beta-cell life cycle, thereby confirming specificity of SC, with respect to induction of beta-cell mitogenicity. For the second purpose, we examined the products of PD-1, a gene located in the cytoplasm of SC, where it promotes spermatogenesis. By blocking the protein encoded by PD-1, under appropriate culture conditions, we observed that the SC-induced increase in beta-cell mitotic activity lost its statistical significance, which suggested a role of PD-1 with respect to SC-related mitogenic properties on beta-cells. These findings corroborate the idea that SC, by either direct contact, or by means of their secretory products, clearly affect the islet beta-cell mitotic rate. Preliminarily, PD-1 gene, located in the cytoplasm of SC, might be one of the factors involved with the induction of beta-cell mitotic activity. In conclusion, SC-induced beta-cell mitotic activity is specific, seemingly mediated by humoral factors whose acting mechanisms have started being unfolded.     

Selective determination of cholesterol in high density lipoprotein subfractions (HDL2 and HDL3) in patients with cerebral and peripheral arteriosclerosis

Cholesterol levels in high density lipoprotein subfractions (HDL2 and HDL3) were evaluated in 69 patients (55 males, average age +/- SD 58.3 +/- 8.8, and 14 females, average age +/- SD 63.1 +/- 10.3) with extra-coronary arteriosclerosis (lower limbs, supraaortic trunks and both sites), and in 79 healthy age-matched control subjects. HDL cholesterol was significantly reduced in male and female patients. The HDL cholesterol decrease was due to a fall in both HDL2 and HDL3 cholesterols; nonetheless, an analysis of the HDL2-cholesterol/HDL3-cholesterol ratio disclosed that HDL2 cholesterol was the most reduced. Slightly higher plasma cholesterol and triglyceride levels were found in the patients as well as a higher plasma cholesterol/HDL-cholesterol ratio. On the contrary, the HDL2-cholesterol/HDL3-cholesterol ratio was significantly reduced in the patients. These preliminary findings suggest that, as in ischemic heart disease, the HDL cholesterol reduction in cerebral and peripheral arteriosclerosis is also mainly due to a reduction in the HDL2 subfraction. These results also lend further support to the proposal that determination of the HDL subfractions is useful for a better assessment of the risk profile for arteriosclerosis.     

In vitro evaluation of permeation,toxicity and effect of praziquantel-loaded solid lipid nanoparticles against Schistosoma mansoni as a strategy to improve efficacy of the schistosomiasis treatment

Solid lipid nanoparticles (SLN) are a promising drug delivery system for oral administration of poorly-water soluble drugs because of their capacity to increase the solubility of drug molecules when loaded in their lipid matrices, with the resulting improvement of the drug bioavailability. In the present work, we have developed praziquantel (PZQ)-loaded SLN and explored the biological applications of this system for intestinal permeation of PZQ. The effect in vitro on Schistosoma mansoni culture and the cytotoxicity in HepG2 line cell were also evaluated. The results showed a significant decrease in the intestinal absorption of PZQ loaded in SLN compared to free PZQ, suggesting that the SLN matrix could act as reservoir system. In culture of S. mansoni, we observed that PZQ-loaded SLN were more effective than free PZQ, leading the death of the parasites in less time. The result was proportional to doses of PZQ (25 and 50 μg mL⁻¹) and lipid concentration. Regarding cytotoxicity, the encapsulation of PZQ into SLN decreased the toxicity in HepG2 cells in comparison to the free PZQ. From the obtained results, PZQ-loaded SLN could be a new drug delivery system for the schistosomiasis treatment especially in marginalized communities, improving the therapeutic efficacy and reducing the toxic effects of PZQ.     

Effects of transforming growth factor-beta1 and tumour necrosis factor-alpha on cultured fibroblasts from skin fibroma as modulated by toremifene

To determine how toremifene, an anti-oestrogen triphenylethylene derivate, reduces tumour mass, we investigated its modulation of TGF-beta1 and TNF-alpha in fibroma fibroblasts. Normal and fibroma fibroblasts, isolated from patients affected by Gardner's syndrome without or with fibroma manifestation, were cultured in vitro. Secretion of GAG, collagen and TGF-beta1 was increased in fibroma fibroblasts compared to healthy cells. The increase in TGF-beta1 secretion into the medium was associated with a parallel increase in TGF-beta1 gene expression and receptor number. Receptor cross-linking studies using radiolabelled TGF-beta1 revealed more receptors, particularly types I and II, in fibroma fibroblasts than in normal cells. Normal and fibroma fibroblasts did not synthesise TNF-alpha, but they had TNF-alpha membrane receptors, as shown by TNF-alpha assay. TNF-alpha secreted by human monocytes, which may be present in the peritumoral area, increased cell proliferation and GAG accumulation and was, in turn, enhanced by TGF-beta1 treatment. Both growth factors increased angiogenesis, as shown by the CAM assay. Toremifene reduced TGF-beta1 secretion by fibroma fibroblasts and TNF-alpha secretion by monocytes, thus downregulating cell proliferation, ECM macromolecule accumulation and angiogenic progression. We hypothesise that increased TGF-beta1 gene expression and TGF-beta1 secretion in fibroma fibroblasts as well as the subsequent rise in TNF-alpha production by monocytes may facilitate fibroma growth and that toremifene inhibits autocrine and paracrine growth factor production.     

Hyperbaric oxygen in diabetic gangrene treatment

We treated a group of 18 hospitalized adult diabetic patients (all with retinopathy, 17 with symptomatic neuropathy, and 6 with macroangiopathy) presenting with gangrenous lesions of the foot by a combined regime consisting of strict metabolic control, daily debridement of necrotic tissues, and daily hyperbaric oxygen (HBO) treatments given in a multiplace oxygen chamber. Another group of 10 adult subjects with comparable foot lesions (all with retinopathy, 9 with symptomatic neuropathy, and 4 with macroangiopathy) was treated in exactly the same way except for HBO. In the test treatment group, 16 patients were healed, and the remaining 2 showed no improvement and later underwent amputation. The number of HBO treatments required for healing was significantly related to the size of gangrenous lesions. In the non-HBO-treated group, only 1 patient improved, 5 of 10 showed no change, and 4 of 10 worsened until leg amputation was unavoidable. Comparison of the two groups by chi 2-test revealed a highly significant difference (P = .001). In practical terms, HBO treatment drastically reduced leg amputations in patients so treated in the last 3 yr compared with earlier and current figures for patients not receiving HBO treatment.     

Analysis of prognostic factors and clinicopathological staging of thymoma

The prognostic value of four clinical variables (age and sex of patients, association with myasthenia gravis, and clinical stage) and histological type was analyzed in 83 consecutive patients with thymoma, histologically classified as cortical, medullary, and mixed. Age, sex, and association with myasthenia gravis did not prove to represent significant prognostic factors; clinical stage and histological type, on the contrary, had a highly significant prognostic value (p less than 0.001). A model of clinicopathological staging, based on both clinical stage and histological type, in which three major prognostic groups are considered is proposed. The degree of significance of this model is higher (p less than 0.0001) than that of clinical stage and histological type considered individually; its validity is further supported by the results of multivariate analysis according to the Cox regression model (p = 0.0001). We think it represents a prognostically valuable approach to the problem of management of thymoma.     

HBV and HIV expression in lymph nodes of HIV positive LAS patients: histology and in situ hybridization

The presence of hepatitis B virus (HBV) and human immunodeficiency virus (HIV) was investigated using hybridization in 15 lymph nodes and one Kaposi's sarcoma skin lesion obtained from HIV-positive patients. Cryostat tissue sections were hybridized with chemically modified DNA probes for HBV and HIV. HIV genome was mainly observed in the cytoplasm of cells present in 7/15 lymph nodes and in the Kaposi's sarcoma skin lesion, thus indicating the expression of HIV replication. Control samples hybridized with an HTLV I probe were negative. HBV genome was found in the cytoplasm of lymphoid mononuclear cells in 2/7 lymph nodes, obtained from HIV+ patients without serum markers of ongoing HBV infection. Lymph node positivity for HBV DNA also confirms that lymphoid cells may be a target for HBV. Since HBV infection seems to precede HIV infection in nearly all patients, it is possible that it may represent a factor facilitating the development of the HIV-related disease.