Cerebral arteriovenous malformations in children: neuroimaging findings

Cerebral arteriovenous malformations (CAVMs) are uncommon in children. CAVMs represent the most frequent intracranial vascular pathology at pediatric ages. This report concerns 13 children below the age of 16; all were identified between September 1995 and December 1996 with 14 CAVMs among them. All were proved by conventional cerebral angiography (CCA). Thirteen computed tomography (CT), 7 magnetic resonance images (MRI), 2 magnetic resonance angiography (MRA) and 13 conventional cerebral angiography (CCA) were analyzed. Most CAVMs nidus were located in cerebral hemispheres. Four in the temporal lobe, two in the parietal lobe, three in the frontal lobe, two in the occipital lobe, and three in the corpus callosum. One of them was of a mixed type with two nidi. The major clinical features of CAVMs were intracranial hemorrhage and seizures. Experience here was that MRI is superior to CT in showing the exact anatomic relationships of the nidus and in demonstrating the extent of CAVMs nidus obliteration after treatment. MRA provided a noninvasive means of studying blood vessels and vascular pathology in relationship to the CAVMs nidus. Standard angiography is still necessary to characterize in-flow and out-flow of vessels in CAVMs when definitive treatment is considered.     

Inhibition of proliferation and expression of T-antigen in SV40 large T-antigen gene-induced immortalized cells following transplantations

In this paper the Authors reviewed the recent literature for a more comprehensive and clear vision of the epidemiological and pathological aspects of retroperitoneal sarcomas. The most effective procedures for a an early and accurate diagnosis were identified. Moreover, the different therapeutic choices were taken into account focusing on those provided of the major potential in terms of oncologically valid treatment.     

Kinematic analysis of shear displacement as a means for operating mechanotransduction channels in the contact region between adjacent stereocilia of mammalian cochlear hair cells

In sensory hair cells of the cochlea, deflection of the stereociliary bundle results in direct mechanical gating of mechanoelectrical transduction channels, a function generally attributed to the tip link running between the tips of short stereocilia and the sides of adjacent taller ones. However, immunocytochemical experiments indicate that the channels may not be associated with the tip link but occur just below it in a region of contact between the stereocilia. To determine whether transduction channels in this location could be operated during physiologically appropriate deflections as effectively by shear displacement as if they were associated with the tip link, a two dimensional kinematic analysis of relative motion between stereocilia has been performed assuming contact between stereocilia is maintained during deflection. Bundle geometry and dimensions were determined from transmission electron micrographs of hair cells from several frequency locations between 0.27 and 13.00 kHz in the guinea-pig cochlea. The analysis indicates that for a 10 nm deflection of the tallest stereocilia of both inner and outer hair cells, i.e. within the range of the maximum sensitivity of mammalian hair bundles, the average shear displacement in the contact region would be 1.6 nm, but that it increases systematically towards higher frequency regions for outer hair cells. This displacement is comparable in magnitude to tip-link elongation for individual stereociliary pairs.     

Attenuation of neutrophil and endothelial activation by intravenous morphine in patients with acute myocardial infarction

To investigate the effects of morphine on neutrophil and endothelial activation, we measured serum levels of intercellular adhesion molecule-1 (ICAM-1), L-selectin, and neutrophil endopeptidase 24.11 (NEP) in 38 patients with acute myocardial infarction (group 1) and 16 control subjects (group 2). In group 1, all the patients underwent blood sampling at initial presentation and 10 minutes later. Twenty of them had 3 mg of morphine administered intravenously immediately after the first sampling (group 1A) and the other 18 after a second sampling (group 1B). The serum levels of ICAM-1 and L-selectin were both significantly higher in groups 1A and 1B than in group 2. In group 1A, the ICAM-1 decreased significantly at second blood samplings (310 +/- 28 vs 368 +/- 30 ng/ml; p <0.001), whereas in group 1B there was no significant change in ICAM-1 (357 +/- 33 vs 359 +/- 26 ng/ml; p = NS). In group 1A, the L-selectin decreased significantly at second blood samplings (2.3 +/- 1.2 mg/L, p <0.001 vs baseline), whereas in group 1B there was no significant change in L-selectin (3.9 +/- 1.0 mg/L, p = NS vs baseline). There was no significant difference in baseline NEP activities between groups 1A and 1B (4.89 +/- 1.22 vs 5.14 +/- 1.57 nmol/mg protein; p = NS). However, the NEP activities at second blood samplings decreased significantly in group 1A (9.88 +/- 1.86 nmol/mg protein, p <0.001 vs baseline), whereas no significant changes were observed in group 1B (5.09 +/- 1.62 nmol/mg protein, p = NS vs baseline). In conclusion, morphine increased NEP activities and thus attenuated shedding of L-selectin and ICAM-1.     

Risk factors and outcome of human immunodeficiency virus-infected patients with sporadic multidrug-resistant tuberculosis in New York City

The discovery of neuroendocrine differentiation in hormone-refractory prostatic adenocarcinoma has opened a potentially new therapeutic approach in this group of patients with a poor prognosis and few effective therapy modalities. Based on previous findings of increased uptake of 11C-5-hydroxytryptophan (11C-5-HTP) in neuroendocrine tumours using the PET technique, this tracer was applied in the study of 10 patients with metastatic hormone-refractory prostatic adenocarcinoma. In three patients, the study was repeated after treatment. An increased uptake of 11C-5-HTP was observed in all investigated skeletal lesions, although the magnitude of the uptake was moderate. The difference between the standard uptake values (SUV) in normal bone and metastatic lesions was significant (p < 0.001). A kinetic analysis of the uptake of 11C-5-HTP demonstrates an increase during the first minutes followed by a wash-out and a stabilization of the tissue/blood ratio at about 2. The Patlak plots demonstrated a gradual increase in the transport rate during the first 20 to 30 min, after which a constant level was observed. The SUV varied between patients and between lesions over time and treatment. The uptake of 11C-5-HTP discriminates metastatic lesions from normal bone and may thus aid in the diagnosis and, potentially, in treatment monitoring of metastatic hormone-refractory prostatic adenocarcinoma. Uptake kinetics are characterized by a wash-out and cannot alone be used as proof of neuroendocrine differentiation in hormone-refractory prostatic adenocarcinoma.     

Instantaneous and residual stresses developed in hot isostatic pressing of metals and ceramics

Under many conditions, hot isostatic pressing (HIP) of metallic or ceramic porous preforms occurs by the densification of a shell at the surface of the preform, which then thickens until the whole sample is fully densified.^[2,4] The development of such a dense shell reduces the effective pressure acting to densify the remaining porosity. Furthermore, this pressure difference can lead to anisotropic creep of the shell, and this may be a contributary cause of shape change of samples during HIP. The stresses occurring during cooling of the sample and the residual stresses are calculated as a function of all of the various material and pressing parameters. It is found that, in many cases, the cooling stresses which are tensile at the surface may well be large enough to cause cracking in ceramic samples.     

Pseudobacteriuria associated with a urine flow rate transducer

Normal wound healing in skin embraces several reparative processes, many of which directly involve components of the extracellular matrix and the cutaneous basement membrane zone. Proteoglycans are a group of extracellular matrix macromolecules that have both structural and regulatory properties. In wound healing, certain proteoglycans fulfill a mechanical function of absorbing water and preventing tissue compression. However, proteoglycans may also have other roles in wound healing including a direct influence on inflammation, cell attachment and migration, and growth factor binding. Furthermore, proteoglycans may help to determine other aspects of the long-term quality of wound healing in skin through regulation of basement membrane permeability, epidermal hyperproliferation, and dermal fibrosis.