Oral contrast agents for magnetic resonance imaging of the bowel

The development of fast imaging sequences, which provide the ability to acquire motion-free T1- and T2-weighted images of static fluids, has greatly increased the interest in magnetic resonance imaging of the small bowel. Luminal distension is a necessary prerequisite for small bowel imaging methods because collapsed bowel loops can hide even large lesions and may mimic wall thickening. Poor distension of normal bowel loops in basal conditions has led researchers to study different oral contrast media to optimally distend the bowel lumen. Several MR oral contrast agents with various signal properties are available. According to these signal properties, agents are classified as positive ("bright" lumen), negative ("dark" lumen), or biphasic ("bright" lumen on T1 and "dark" on T2, or conversely "dark" lumen on T2 and "bright" on T1). Positive contrast agents cause a reduction in T1 relaxation time; consequently, these agents act on T1-weighted images by increasing the signal intensity of the bowel lumen. Negative contrast agents are based on superparamagnetic particles and act by inducing local field inhomogeneities, which results in shortening of both T1 and T2 relaxation times. Using superparamagnetic contrast agents, T2-weighted effects are predominant. Biphasic contrast agents are substances that have different signal intensities on different sequences, depending on the concentration at which they are administered. The choice of a single agent presents advantages and disadvantages; thus, the radiologist should choose the appropriate contrast medium according to the clinical setting, MR experience, availability of the agent, and patient tolerance.     

PS-341, a novel proteasome inhibitor,induces Bcl-2 phosphorylation and cleavage in association with G2-M phase arrest and apoptosis

Treatment with the proteasome inhibitor, PS-341 resulted in concentration- and time-dependent effects on Bcl-2 phosphorylation and cleavage in H460 cells that coincided with the PS-341-induced G2-M phase arrest. The observed Bcl-2 cleavage paralleled the degree of PS-341-induced apoptosis but was detected to a similar extent with comparable concentrations of two other proteasome inhibitors (MG-132 and PSI). Calpain inhibitors, ALLM and ALLN, and the caspase inhibitors, Z-VAD and AC-YVAD did not induce BcI-2 phosphorylation and cleavage. Exposure to PS-341 resulted in an additional Mr 25,000 cleavage fragment of Bcl-2, whereas only a Mr 23,000 fragment was observed with other anticancer agents. The formation of the Mr 25,000 fragment was not prevented by caspase inhibitors unlike the Mr 23,000 fragment, which suggests mediation by a caspase-independent pathway. Cell fractionation studies revealed that the Bcl-2 cleaved fragments localize within membrane structures and was an early event (at approximately 12 h, posttreatment), and before the observed cleavage of poly(ADP-ribose) polymerase (PARP), beta-catenin, and DNA fragmentation (at approximately 36 h posttreatment). The Mr 23,000 Bcl-2 cleavage product was inhibited by the pan-caspase inhibitor and the inhibitors of capase-3, -8, -9; but the PARP cleavage was prevented only by the pan-caspase and caspase-3 inhibitors, which suggests that the Mr 23,000 Bcl-2 cleavage occurred at both the initiation and execution stages of apoptosis. The inhibition of the ubiquitin/proteasome pathway by PS-341 leads, at an early stage of apoptosis, to Bcl-2 phosphorylation and a unique proteolytic cleavage product, which are associated with G2-M phase arrest and the induction of apoptosis.     

Otzi's last meals: DNA analysis of the intestinal content of the Neolithic glacier mummy from the Alps

Samples of the intestinal content were collected from the ileum and colon of the Neolithic glacier mummy popularly known as the Tyrolean Iceman, or Otzi. DNA was extracted from the samples and PCR amplified, using a variety of primer pairs designed to bind to different genes (mammal mitochondrial 12S ribosomal RNA gene, plant/fungal nuclear 18S ribosomal RNA gene, plant chloroplast ribulose bisphosphate carboxylase large subunit gene). This made it possible to distinguish between animal and plant food residues (macroremains) and pollen (microremains). According to the DNA reconstruction, the man's last meal was composed of red deer (Cervus elaphus) meat, and, possibly, cereals; this meal had been preceded by another one based on ibex (Capra ibex), different species of dicots, and cereals. The DNA spectrum corresponding to pollen residues in the colon, on the other hand, fits with the hypothesis that the last journey of the Neolithic hunter/warrior was made through a subalpine coniferous forest to the site at over 3,200 m above sea level, where his mummified body was to be discovered 5,000 years later.     

Double V-Y advancement flap in the management of lower lip reconstruction

A new method for lower lip reconstruction is proposed. It is based on a double cutaneous and mucous V-Y advancement flap and is suggested for the surgical treatment of lip cancer confined between the skin and the vermilion with a horizontal spread. Sixteen patients were treated from 1996 to 2001 with this technique and the results were satisfactory both from the functional and the aesthetic standpoints.     

A novel intraarterial chemotherapy using paclitaxel in albumin nanoparticles to treat advanced squamous cell carcinoma of the tongue: preliminary findings

OBJECTIVE: The purpose of our study was to evaluate the effectiveness of intraarterial infusion of paclitaxel incorporated into human albumin nanoparticles for use as induction chemotherapy before definitive treatment of advanced squamous cell carcinoma of the tongue. SUBJECTS AND METHODS: Twenty-three previously untreated patients (age range, 27-75 years) who had carcinoma of the tongue (stage T3-T4, any N) received intraarterial therapy with paclitaxel incorporated into albumin nanoparticles delivered by transfemoral catheterization into the external carotid artery (10 patients), selectively into the lingual artery (12 patients), or into a faciolingual trunk (1 patient). Each patient received two to four infusions, with a 3-week interval between infusions. The dose administered was 230 mg/m(2) in eight patients, 180 mg/m(2) in six patients, and 150 mg/m(2) in nine patients. Sixteen patients underwent surgery. Of these 16 patients, eight subsequently received radiotherapy, and three received a combination of chemotherapy and radiotherapy. Of the remaining seven patients, one received chemotherapy alone, four received radiotherapy alone, one received chemotherapy plus radiotherapy, and one refused any further treatment. RESULTS: Sixty-seven infusions were performed successfully. Eighteen patients (78%) had a clinical and radiologic objective response (complete, 26%; partial, 52%). Three patients (13%) showed stable disease, and two (9%) showed disease progression. The four patients with complete clinical response who underwent surgery showed microscopic residual carcinoma measuring less than 1 mm in two patients, less than 5 mm in one patient, and less than 1 cm in one patient. The toxicities encountered were hematologic (grade 3) in two patients (8.6%) and neurologic (grade 4) in two patients (reversible paralysis of the facial nerve, 8.6%). Two catheter-related complications occurred: one reversible brachiofacial paralysis and one asymptomatic occlusion of the external carotid artery. CONCLUSION: Intraarterial infusion of paclitaxel in albumin nanoparticles proved reproducible and effective and deserves further investigation as induction chemotherapy before definitive treatment of advanced tumors of the tongue, with a view to organ preservation.