Volume computed tomography air kerma index and image quality evaluation in Brazil

The aim of this study was to evaluate the image quality of 29 computed tomography (CT) scanners in Brazil and to perform estimations of patient dose and image quality of common CT examinations at these equipment. The volume CT air kerma indexes (C(VOL)) were estimated, using normalised weighted air kerma indexes, supplied by the ImPACT group. The image quality tests were performed using the phantom and accreditation protocol from the American College of Radiology (ACR). The C(VOL) values for head scans varied between 8.7 and 108 mGy. The Hi-res chest examinations presented C(VOL) values varying from 0.4 to 32 mGy. For abdominal scans, the estimated C(VOL) values varied between 4.1 and 94 mGy. This wide variation of air kerma between different centres is related to the scanner type and also to the scanning parameters. The results also showed that the image quality did not attend all ACR CT accreditation requirements.     

Single DNA molecule detection using nanopipettes and nanoparticles

Single DNA molecules labeled with nanoparticles can be detected by blockades of ionic current as they are translocated through a nanopipette tip formed by a pulled glass capillary. The nanopipette detection technique can provide not only tools for detection and identification of single DNA and protein molecules but also deeper insight and understanding of stochastic interactions of various biomolecules with their environment.     

Experimental realization of optical lumped nanocircuits at infrared wavelengths

The integration of radiofrequency electronic methodologies on micro- as well as nanoscale platforms is crucial for information processing and data-storage technologies. In electronics, radiofrequency signals are controlled and manipulated by 'lumped' circuit elements, such as resistors, inductors and capacitors. In earlier work, we theoretically proposed that optical nanostructures, when properly designed and judiciously arranged, could behave as nanoscale lumped circuit elements--but at optical frequencies. Here, for the first time we experimentally demonstrate a two-dimensional optical nanocircuit at mid-infrared wavelengths. With the guidance of circuit theory, we design and fabricate arrays of Si3N4 nanorods with specific deep subwavelength cross-sections, quantitatively evaluate their equivalent impedance as lumped circuit elements in the mid-infrared regime, and by Fourier transform infrared spectroscopy show that these nanostructures can indeed function as two-dimensional optical lumped circuit elements. We further show that the connections among nanocircuit elements, in particular whether they are in series or in parallel combination, can be controlled by the polarization of impinging optical signals, realizing the notion of 'stereo-circuitry' in metatronics-metamaterials-inspired optical circuitry.     

Determinants of dietary intake in a sample of white and Mexican-American children

Using a modified method consisting of chromatography on phenyl-Sepharose, Q-Sepharose, and hydroxyapatite, we isolated a highly purified heat shock protein with molecular weight 90 kD (Hsp90) from rabbit liver. The isolated protein was recognized on immunoblot by commercially available monoclonal anti-Hsp90 antibodies. The chromatographic properties, interaction with actin and calmodulin, phosphorylation in the presence of Mg-ATP, and one-dimensional peptide maps of rabbit liver Hsp90 are similar to the corresponding properties of Hsp90 isolated from other sources. In the presence of soluble carbodiimide and N-hydroxysuccinimide, rabbit liver Hsp90 can be cross-linked with calmodulin, troponin C, troponin I, and calponin. The data obtained indicate that Hsp90 may participate in the assembly of regulatory proteins of the actin filament.     

Small-diameter (2 mm) laparoscopy in the evaluation of liver disease

We report the case of a pathological mediopatellar plica found in the right knee of a 15-month-old infant girl. Flexion contracture of the knee was found to be 40 degrees. An arthroscopic view showed a large and thick voluminous mediopatellar plica. It was trapped between the patella and the medial femoral condyle and it was in tight contact with the medial facet of the patella at 40 degrees flexion in the knee, blocking further extension. A longitudinal groove was noted on the articular surface of the medial femoral condyle that looked as if it had another trochlea on arthroscopic view. The mediopatellar plica came into contact with the groove at 60 degrees flexion in the knee and it fitted precisely into the groove at further flexion. The pathological plica was resected arthroscopically, which resulted in approximately 10 degrees improvement in extension of the knee. Histological examination found hypertrophy and chronic nonspecific inflammation of the synovium. The patient was helped with range-of-motion exercise and quadriceps-strengthening exercise. At 27 months follow-up, the knee had gained full extension. This article reports that a pathological mediopatellar plica may develop in infants.     

The renal and hepatic distribution of Bence Jones proteins depends on glycosylation: a scintigraphic study in rats

The aim of the present study was to evaluate renal and liver distribution of two monoclonal immunoglobulin light chains. The chains were purified individually from the urine of patients with multiple myeloma and characterized as lambda light chains with a molecular mass of 28 kDa. They were named BJg (high amount of galactose residues exposed) and BJs (sialic acid residues exposed) on the basis of carbohydrate content. A scintigraphic study was performed on male Wistar rats weighing 250 g for 60 min after i.v. administration of 1 mg of each protein (7.4 MBq), as the intact proteins and also after carbohydrate oxidation. Images were obtained with a Siemens gamma camera with a high-resolution collimator and processed with a MicroDelta system. Hepatic and renal distribution were established and are reported as percent of injected dose. Liver uptake of BJg was significantly higher than liver uptake of BJs (94.3 vs 81.4%) (P < 0.05). This contributed to its greater removal from the intravascular compartment, and consequently lower kidney accumulation of BJg in comparison to BJs (5.7 vs 18.6%) (P < 0.05). After carbohydrate oxidation, there was a decrease in hepatic accumulation of both proteins and consequently a higher renal overload. The tissue distribution of periodate-treated BJg was similar to that of native BJs: 82.7 vs 81.4% in the liver and 17.3 vs 18.6% in the kidneys. These observations indicate the important role of sugar residues of Bence Jones proteins for their recognition by specific membrane receptors, which leads to differential tissue accumulation and possible toxicity.