Neuroimaging in Pineal Tumors

BACKGROUND AND PURPOSE: The authors report radiological findings in 11 tumors in the pineal region, which were histologically diagnosed as germinomas, pineocytomas pineoblastomas, ependymomas, teratomas, and astrocytomas. METHODS: Computed tomography (CT) was performed in seven patients and magnetic resonance imaging (MRI) was performed in all patients. RESULTS: CT showed a solid or solid/cystic mass with variable contrast enhancement. MRI showed a heterogeneous mass, with hypointense signal on T1 and iso/hyperintense signal on T2-weighted images (WI) and gadolinium enhancement. Extension to adjacent structures occurred in five patients and spread through the cerebral spinal fluid (CSF) in two. CONCLUSIONS: Pineal region tumors have no pathognomonic imaging pattern. MRI and CT are complementary in diagnosis and are important to determine localization, extension, and meningeal spread.     

Predicted and Measured Muscle Forces after Recoveries of Differing Durations Following Fatigue in Functional Electrical Stimulation

Abstract: Using ³¹P nuclear magnetic resonance (NMR) spectroscopy, the bioenergetics of paralyzed muscles activated by functional electrical stimulation (FES) were studied in vivo during fatigue and recovery on paraplegic subjects. During the activation phase of the muscle, the muscle force was also monitored. The phosphorus metabolites were found to vary systematically during fatigue and to recover slowly to their rest state values after cessation of FES. During fatigue, a good correlation was found between the decaying force and each of the profiles of phos-phocreatine, inorganic phosphorus, and intracellular pH. A musculotendon 5 element model was proposed for the activated muscle to predict its force generation capacity. A fatigue recovery function, based on the metabolic profiles, was introduced into the model. This model allowed us to predict the force expected to be developed as a function of the time after recovery of given time durations. Validation experimental measurements of force were carried out and included recurrent fatigue tests, both in the initially un-fatigued state and at various times in the postfatigue stage of the muscle. Comparison of the predicted and measured forces indicated satisfactory agreement of the results. The developed model of muscle dynamics should help to design a strategy for reducing muscle fatigue under FES.     

Is balance impaired by recurrent sprained ankle?

OBJECTIVE: To evaluate uninjured and recurrent sprained ankles during single leg standing, both with and without visual input, and the contribution of related proprioceptive feedback in this event. METHODS: A force measuring system was used for monitoring reaction forces in the anteroposterior and mediolateral directions during single leg standing. Differences between selected variables obtained in the uninjured and sprained ankles were analysed using two way analysis of variance. RESULTS: Foot-ground reaction forces in both anteroposterior and mediolateral directions were the same in normal and sprained ankles of each subject while standing with either open or closed eyes. However, standing with closed eyes, irrespective of the ankle status, always produced significantly higher reaction forces than those obtained with open eyes (P < 0.05). CONCLUSIONS: The amount of postural sway during single leg standing is similar in the chronically sprained and the uninjured ankle joint.     

Morphometric characteristics of the cells in non-tumoral processes and tumors of the adrenal glands

A comparative morphometric study of the cells was carried out by the Integral-2MT television cytologic analyzer, and the DNA quantitative estimation by flow cytofluorometry in 31 patients with adrenal tumors and hyperplastic involvements. The shifts in all the morphometric parameters in cortical adenoma and hyperplasia were found statistically insignificant, with similar (diploid) DNA cytograms. The differences in all the morphometric parameters (except the cellular and nuclear shape) were statistically significant in pheochromocytoma and hyperplasia of the cortex, with the pheochromocytoma DNA histograms showing higher counts of cells with DNA content higher than 2S. Assessment of the total group of malignant tumors of the adrenals (malignant pheochromocytoma, cortical carcinoma) has shown statistically significant differences in the mean characteristics (except cellular and nuclear shape) of these tumors and adrenocortical hyperplasia. In adrenocortical carcinoma 2 of the 3 histograms were aneuploid with a considerable count of cells with DNA content higher than 2S. The objective parameters may be used in the differential cytologic diagnosis of nontumor involvements and tumors of the adrenals.     

Lactic dehydrogenase virus (LDV) impairs the antigen-presenting capacity of macrophages yet fails to affect their phagocytic activity

The effect of acute infection of mice with lactic dehydrogenase virus (LDV) on two major functions of peritoneal macrophages was tested. Using a macrophage-dependent T cell proliferative assay to test the antigen-presenting capacity of LDV-infected macrophages we found that LDV impairs the capacity of antigen-presenting cells to trigger memory T lymphocytes. Endocytosis of antigen by LDV-infected macrophages was similar to that of uninfected cells. In addition, the proportion of intracellular antigen versus membrane-bound antigen in LDV-infected cells were similar to that observed in uninfected mice. It appears therefore, that the impaired immunogenic effect of LDV-infected macrophages results from reduced immunogenicity of the membrane-bound antigen.Testing the phagocytic activity of peritoneal macrophages we found that the uptake of radiolabeled antibody-coated sheep erythrocytes or bacteria (E. coli) by infected cells was similar to that by uninfected macrophages. In addition, LDV failed to affect the ability of peritoneal macrophages in a nitroblue tetrazolium reduction reaction which serves as an alternative parameter for measuring phagocytic activity. Our results support the assumption that LDV, which probably propagates in the cells of the reticuloendothelial system, impairs some of the immunogenic functions of macrophages and thereby affects macrophage-dependent immune responses.     

Protein kinase Ctheta: a new essential superstar on the T-cell stage

Recent studies have identified protein kinase Cθ (PKCtheta), a member of the Ca(2+)-independent PKC family, as an essential component of the T-cell synapse that cooperates with calcineurin to activate the interleukin-2 (IL-2) gene. Several selective functions of PKCtheta involved in the activation and survival of T cells are reviewed herein. Among these, the nuclear factor-kappaB (NF-kappaB) signaling cascade appears to be the most critical target of PKCtheta in the T-cell receptor/CD28 costimulatory pathway that leads to T-cell activation.     

Amputation of the lower limb as palliative treatment for debilitating musculoskeletal cancer

Limb sparing surgery has replaced amputation surgery for treating sarcomas of the lower limb in most cases. Wide resection followed by postoperative radiation therapy can achieve acceptable local control and survival rates in patients with bone and soft-tissue sarcomas of the lower limb. Recurrent or persistent disease constitutes a major oncological problem. Local symptoms such as agonizing pain, fractures, tumor fungation, inability to walk and inability to maintain daily activities, further impair the patient's quality of life. In this clinical set-up palliative amputation of the limb should be considered. Fourteen patients with soft-tissue or bone sarcomas underwent palliative major amputation. The procedures included: hemipelvectomy, hip disarticulation, knee disarticulation, above or below-knee amputation. Local control of the disease and pain, and improvement of the performance status were observed in 13 evaluable patients. The mobility was restored in 13/14 patients. The median survival following the procedure was 9 months. There was only one case of immediate post-operative death. Severe phantom pain was not reported by any of the patients. Quality of life was reported to be improved by two-thirds of the patients. We found palliative major amputation surgery worth-performing in low-performance status cancer patients with locally advanced disease of the lower limb.