Phase-contrast enhanced synchrotron micro-tomography of human meniscus tissue.

OBJECTIVE: To investigate the feasibility of synchrotron radiation-based phase contrast enhanced micro-computed tomography (SR-PhC-µCT) for imaging of human meniscus. Quantitative parameters related to fiber orientation and crimping were evaluated as potential markers of tissue degeneration. DESIGN: Human meniscus specimens from 10 deceased donors were prepared using different preparation schemes: fresh frozen and thawed before imaging or fixed and paraffin-embedded. The samples were imaged using SR-PhC-µCT with an isotropic voxel size of 1.625 µm. Image quality was evaluated by visual inspection and spatial resolution. Fiber voxels were defined using a grey level threshold and a structure tensor analysis was applied to estimate collagen fiber orientation. The area at half maximum (FAHM) was calculated from angle histograms to quantify orientation distribution. Crimping period was calculated from the power spectrum of image profiles of crimped fibers. Parameters were compared to degenerative stage as evaluated by Pauli histopathological scoring. RESULTS: Image quality was similar between frozen and embedded samples and spatial resolutions ranged from 5.1 to 5.8 µm. Fiber structure, including crimping, was clearly visible in the images. Fibers appeared to be less organized closer to the tip of the meniscus. Fiber density might decrease slightly with degeneration. FAHM and crimping period did not show any clear association with histopathological scoring. CONCLUSION: SR-PhC-µCT is a feasible technique for high-resolution 3D imaging of fresh frozen meniscus tissue. Further work is needed to establish quantitative parameters that relate to tissue degeneration, but this imaging technique is promising for future studies of meniscus structure and biomechanical response.

Assessment of Salmonella survival in dry-cured Italian salami.

The inactivation of Salmonella during curing of Italian traditional pork salami was investigated. A total of 150 batches of ground raw meat (GRM) used for salami manufacturing by four producers were tested for Salmonella by real-time PCR followed by ISO 6579 cultural confirmation and MPN enumeration. Salami produced with Salmonella positive GRMs were re-tested at the end of their curing period. Aw, pH and NaCl content were also measured. Detection of Salmonella was performed testing both 25 and 50g of the samples. By Real-Time PCR 37% of the GRMs resulted positive, but cultural detection of Salmonella was obtained in 14% of the samples only. Salmonella enumeration ranged from 31 MPN/g to <1.3 MPN/g. The difference between testing 50g and 25g of the samples was statistically significant (p value≤0.01). In particular, ISO-50g detected Salmonella in 100% of all positive samples, vs. 62% of ISO-25g. Salami made of the contaminated GRMs were 29% Salmonella-positive, as most batches of salami produced with Salmonella-positive GRMs resulted negative after regular curing (20-48days). Overall, 13% of salami produced with Salmonella-contaminated GRMs were positive. They belonged to six batches, which turned out negative after prolonged curing ranging between 49 and 86days. Salmonella enumeration in salami ranged from 8.7 MPN/g to <1.3 MPN/g. Unlike GRMs, no significant difference was observed between the ISO-50g and the ISO-25g in detecting Salmonella in cured salami (p value: >0.05). The most common Salmonella serovars in GRMs were Derby (52%), Typhimurium monophasic variant 4, (Barbuti et al., 1993), 12:i:- (19%) and Stanley (10%). Salmonella Derby (56%), London, Branderup, Panama (13%, respectively) and Goldcoast (6%) were most frequent in cured salami. The study showed negative correlation between real-time CT values and cultural confirmation of Salmonella, as well as the importance of sample size for Salmonella detection. Among considered factors with possible effect on the occurrence of Salmonella in salami, statistical analysis revealed a role for aw in salami and for Salmonella load in GRMs, while pH and NaCl content did not significantly affect the probability of finding Salmonella in dry-cured salami in the context of this study. In particular the lower aw values due to longer curing were associated with lower Salmonella presence in traditional dry-cured salami.

Analysis of UbcH10 expression represents a useful tool for the diagnosis and therapy of astrocytic tumors.

Previous studies suggest the expression of UbcH10 gene, that codes for a protein belonging to the ubiquitin-conjugating enzyme family, as a valid indicator of the proliferative and aggressive status of tumors of different origin. Therefore, to look for possible tools to be used as diagnostic markers in astrocytic neoplasias, we investigated UbcH10 expression in normal brain, gliosis and low-grade and high-grade astrocytic tumors by immunohistochemistry. UbcH10 expression was observed in low-grade astrocytoma and in glioblastoma. Our data indicate a clear correlation between UbcH10 expression and the histological grade of the astrocytic tumors. Moreover, the analysis of UbcH10 expression allows the differentiation between gliotic and malignant tissues. Finally, since proteasome inhibitors have recently been considered as possible drugs in the chemotherapy of various tumors, our results would suggest new perspectives for the treatment of brain malignancies based on the suppression of the UbcH10 function.

Treating voxel geometries in radiation protection dosimetry with a patched version of the Monte Carlo codes MCNP and MCNPX.

The question of Monte Carlo simulation of radiation transport in voxel geometries is addressed. Patched versions of the MCNP and MCNPX codes are developed aimed at transporting radiation both in the standard geometry mode and in the voxel geometry treatment. The patched code reads an unformatted FORTRAN file derived from DICOM format data and uses special subroutines to handle voxel-to-voxel radiation transport. The various phases of the development of the methodology are discussed together with the new input options. Examples are given of employment of the code in internal and external dosimetry and comparisons with results from other groups are reported.

Computer- and robot-assisted total knee replacement: analysis of a new surgical procedure.

This paper describes a nonstandard procedure for total knee replacement (TKR), based on the use of modern tools such as computers, electronic sensors, and robots, to achieve accurate and optimal implant results. The intervention is planned on a standard PC connected to the CT scanner. Dedicated software shows the surgeon limb alignment and knee status and assists in the choice of the best prosthesis. The intervention is then performed with a new device and surgical procedure. At first the femur and the tibia are fixed to the operating table with a special clamp and the knee bones are exposed with the standard technique; then the surgeon digitizes the shape of the joint and the computer transfers the planned surgical strategy to a dedicated surgical robot. Resections are performed by the surgeon on a constrained guide held by the robot. In this paper we summarize the main results on the system performances, and discuss the clinical implications of this new technology in the operating room. Preliminary experiments on cadavers and volunteers show that this methodology can improve the accuracy of the implant to 2.5 mm and 20, reduce operating time and surgical errors, and may represent a challenging alternative methodology for TKR.

Radiation dose to the testes after 131I therapy for ablation of postsurgical thyroid remnants in patients with differentiated thyroid cancer.

UNLABELLED: Radioiodine-131 is used in differentiated thyroid cancer (DTC) for ablation of postsurgical thyroid remnants and destruction of metastases. The question may be raised of whether 131I treatment of DTC in male patients may give an irradiation dose to the testes that could impair fertility. Few data in the literature concern the dose absorbed by the testes after 1311 therapy for DTC. Because 131I kinetics may be altered by the hypothyroid condition commonly present at the time of treatment and by the radioiodinated iodoproteins released by the damaged thyroid tissue, the dose values reported in the International Commission on Radiological Protection (ICRP) tables for euthyroid men may not be appropriate. To clarify this problem, three male subjects undergoing 131I therapy for ablation of thyroid remnants shortly after thyroidectomy for DTC were studied. METHODS: The mean administered activity was 1256 MBq, and the duration of the study was 2 wk. The gamma dose was measured by thermoluminescent dosimeters (TLDs) applied to the lower poles of the testes. Correction factors were calculated for the distance of the TLD from the center of the testes and for attenuation by the testes of the gamma rays reaching the TLD. After correction, the gamma dose to the testes ranged from 21 to 29 mGy. The gamma dose calculated by the Medical Internal Radiation Dose (MIRD) method from blood and urine samples was similar (18-20 mGy) to that measured by TLDs. The beta dose was estimated by the MIRD method from blood activity and testicular volume and ranged between 14 and 31 mGy. RESULTS: The total (beta and gamma) doses to testes were 30, 33 and 43 microGy/MBq in the three subjects. CONCLUSION: These values are close to those derived from the ICRP tables (26-37 microGy/MBq 131I) for euthyroid subjects. The present data indicate that significant irradiation is delivered to the testes after the administration of the 131I ablative dose to thyroidectomized patients. The relevance of the radiation absorbed by testes on fertility remains to be established.

Immune and nonimmune regulation of the population of Trypanosoma musculi in infected host mice.

A clear understanding of the population dynamics of trypanosome infections is lacking. In the case of murine Trypanosoma musculi infections, there are no answers to questions concerning (i) the nature of the prolonged plateau phase during which the number of parasites present in the host remains nearly constant (is it a static or dynamic steady state?); (ii) the origin of new parasites, if the plateau is a dynamic steady state, given the relatively early disappearance of generative forms from the bloodstream; and (iii) the role, if any, of a putative ablastin (reproduction-restricting antibody) in regulating the population dynamics of T. musculi infections. We describe here the results of studies of the number and distribution of mature and reproductive forms (RF) in the blood and peritoneal space of both immunocompetent and cyclophosphamide-treated mice throughout the course of infection. While the RF disappeared from the blood within a few days after parasite inoculation, a high fraction (20 to 30%) of the parasites in the peritoneal space were RF throughout the course of infection and, thus, represented a source of new parasites. If an ablastin is responsible for inhibiting RF in the blood, it appeared to have no effect on RF in the peritoneal space. The results of this investigation support the conclusion that the control of the dynamics of T. musculi infections is largely nonimmunological (until cure of the infection) and probably is exercised by the supply of nutrients and reproduction-inhibiting (nonimmunological) and maturation-promoting factors that affect the generative fraction of the population.