ObjectivesThe aim of the study was to determine the factors that may contribute to decreases in bone mineral density (BMD) in patients with AIDS. MethodsThis was a prospective, non-randomized study. Dual X-ray absorptiometry (DXA) was used to determine the BMD of the lumbar spine, femoral neck and distal radius in treatment-naïve HIV-infected male patients with AIDS before and after 1 year of treatment with zidovudine (ZDV)/lamivudine (3TC) plus abacavir (ABC) or lopinavir/ritonavir (LPV/r). ResultsBasal DXA was performed in 50 patients with CD4 counts o200 cells/mL and/or any AIDS-defining condition. Thirty-two patients completed 1 year with full adherence (17 on ABC and 15 on LPV/r) and a second DXA was then performed. At baseline, 19% had osteopenia at the lumbar spine and 19% at the femoral neck. Low body weight was related to low BMD. After 48 weeks, BMD loss was significant at the three locations. The percentage of BMD loss at the femoral neck tended to be greater in the lopinavir group (5.3 vs. 3.2%, P 5 0.058). The differences became significant at the lumbar spine (5.7 vs. 2.7%, P 5 0.044). In the multivariate analysis, the treatment with LPV/r remained associated with bone loss at the lumbar spine. ConclusionsOsteopenia is frequent in treatment-naïve HIV-infected men with AIDS. Bone loss is higher with LPV/r-based regimens compared with triple nucleoside reverse transcriptase inhibitors.
Real-time imaging with low-profile coil designs provides significant enhancements to intravascular MRI.
A real-time interactive black-blood imaging system is described. Rapid blood suppression is achieved by exciting and dephasing slabs outside the imaging slice before each imaging excitation. Sharp-profiled radio frequency saturation pulses placed close to the imaging slice provide good blood suppression, even in views containing slow throughplane flow. IN REAL-TIME IMAGING, the visualization of cardiac and vascular structures is often obscured by signal from flowing blood. For applications where flow signal and flow artifacts are obtrusive, images can be significantly improved by using "black-blood" techniques. In addition to improving endocardial border or vessel-wall definition, black-blood techniques suppress flow-related artifacts. It is a challenge to achieve good blood suppression in real time.Currently, the most effective blood suppression techniques used in cardiovascular imaging are based on "double inversion" (1,2). Double inversion sequences suppress blood based on its flow and T 1 properties. A nonselective 180°pulse is immediately followed by a slice-selective Ϫ180°pulse; then a delay before imaging is chosen in order to null the signal from relaxing blood. Double inversion provides excellent blood suppression; however, the long inversion preparation time requires a long repetition time (TR) and is not feasible for real-time imaging.Another technique involves using "spatial presaturation" to suppress blood (3,4). Spatial presaturation techniques suppress blood based only on flow. Immediately before each imaging excitation, a volume or volumes upstream from the slice (usually thick slabs on either side of the imaging slice) are excited and dephased. Since this technique rapidly suppresses blood, it is practical for continuous real-time imaging. This is also a steady-state technique which, for stationary objects, results in consistent signal intensity between measurements. While effective in the presence of fast through-plane flow, this technique produces reduced contrast in views containing predominantly inplane flow (4,5). In the context of real-time imaging, spatial presaturation is a practical choice because it can be done quickly and maintains a steady state.We present a real-time black-blood imaging sequence based on spatial presaturation. Sharp-profiled saturation pulses are used to provide good blood suppression, even in planes containing slow through-plane flow (6,7). The sequence was implemented within an existing real-time interactive imaging environment developed by Kerr et al (8). Extensions to this system include the optional volume saturation of one or two slabs before each imaging excitation, and interactive control over the saturation slab thickness, placement, and flip angle. No breathholding or gating is required. We applied this technique to real-time ventricular wall-motion study and to real-time intravascular imaging. Figure 1 illustrates the basic pulse sequence. Each TR consists of spatial presaturation, which prepares the black-blood contrast, followed by an imaging acquisitio...
Cefdinir is an extended-spectrum oral cephalosporin that is active against pathogens commonly seen in acute community-acquired bacterial sinusitis (ACABS), including Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Two randomized, investigator-blind, multicenter trials (one in the United States and one in Europe) compared two dosage regimens of cefdinir (600 mg once a day for 10 days and 300 mg twice a day for 10 days) to amoxicillin-clavulanate (A-C) (500 mg three times a day for 10 days) for adult and adolescent patients with ACABS. Twelve hundred twenty-nine patients entered the U.S. study, 698 with antral puncture; 569 patients entered the European study, all with antral puncture. Clinical response (cure or improvement) was determined 7 to 14 days and 3 to 5 weeks posttherapy. Microbiologic eradication rates were determined 10 to 30 days posttherapy in a subset of patients who underwent pre- and posttherapy sinus aspirate culture. Rates of adverse events and treatment discontinuations due to adverse events were examined. Cefdinir, given once or twice daily, was as effective clinically (approximately 90% cure rate) as amoxicillin-clavulanate given three times daily in the treatment of ACABS. Microbiologic eradication rates were also similar in the three groups. The major side effect was mild diarrhea, occurring in approximately 20% of each group. Cefdinir caused fewer adverse events requiring treatment discontinuation.
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