Multilayer Transducer for Acoustic Bladder Volume Assessment on the Basis of Nonlinear Wave Propagation

Catheterization remains the gold standard for bladder volume assessment, but it is invasive, uncomfortable to the patient and introduces the risk of infections and traumas. Acoustic measurement of the bladder volume reduces the need for a urinary catheter. Recently, a new method to non-invasively measure the volume of liquid filled cavities in vivo on the basis of nonlinear wave propagation has been introduced. To implement this method, two different multilayer ultrasound transducers were developed. Both transducers consisted of a first piezo-electric layer of lead zirconate titanate (PZT) to transmit waves at a fundamental frequency (2 MHz) and a second piezo-electric layer (copolymer) to receive a wide range of frequencies including harmonics. To suppress the inherent susceptibility of the film to electromagnetic waves, one of the two transducers, i.e., an “inverted” multilayer transducer, had the copolymer layer located inside the structure. The other multilayer transducer, i.e., a “normal” multilayer transducer, had the copolymer film located on the outside. Both transducers were compared with a commercially available broadband piezo-composite transducer, with respect to their transmit and receive transfer functions, their pulse-echo responses and their electromagnetic susceptibility (EMS) in reception. It was concluded that to measure up to at least the third harmonic frequency component with good sensitivity in combination with high transmit sensitivity at the fundamental frequency, a multilayer structure is preferred. To optimize for the EMS in reception, and hence also the signal-to-noise ratio, an inverted geometry, as proposed in this paper, was proven to be most effective. (E-mail: e.merks@erasmusmc.nl)     

Achieving lipoprotein goals in patients at high risk with severe hypercholesterolemia: efficacy and safety of ezetimibe co-administered with atorvastatin

Background

Despite the efficacy of statins in lowering low-density lipoprotein cholesterol (LDL-C) levels, many patients who are at high risk for heart disease with hypercholesterolemia require additional LDL-C level reduction. The cholesterol absorption inhibitor, ezetimibe, has been shown to provide significant incremental reductions in LDL-C levels when co-administered with statins. This study was performed to compare the efficacy and safety of ezetimibe (10 mg) plus response-based atorvastatin titration versus response-based atorvastatin titration alone in the attainment of LDL-C goals in subjects who are at high risk for coronary heart disease (CHD) and are not at their LDL-C goal on the starting dose of atorvastatin.

Methods

This was a 14-week, multicenter, randomized, double-blind, active-controlled study conducted in 113 clinical research centers in 21 countries. Participants were adults with heterozygous familial hypercholesterolemia (HeFH), CHD, or multiple (≥2) cardiovascular risk factors, and a LDL-C level ≥130 mg/dL after a 6- to10-week dietary stabilization and atorvastatin (10 mg/day) open-label run-in period. Eligible subjects continued to receive atorvastatin (10 mg) and were randomized to receive blinded treatment with ezetimibe (10 mg/day; n = 305) or an additional 10 mg/day of atorvastatin (n = 316). The atorvastatin dose in both groups was doubled after 4 weeks, 9 weeks, or both when the LDL-C level was not at its goal (≤100 mg/dL), so that patients receiving combined therapy could reach 40 mg/day and patients receiving atorvastatin alone could reach 80 mg/day. The primary end point was the proportion of subjects achieving their LDL-C level goal at week 14. A secondary end point was the change in LDL-C level and other lipid parameters at 4 weeks after ezetimibe co-administration with 10 mg/day of atorvastatin versus 20 mg/day of atorvastatin monotherapy.

Results

The proportion of subjects reaching their target LDL-C level goal of ≤100 mg/dL was significantly higher in the co-administration group than in the atorvastatin monotherapy group (22% vs 7%; P <.01). At 4 weeks, levels of LDL-C, triglycerides, and non-high-density lipoprotein cholesterol were reduced significantly more by combination therapy than by doubling the dose of atorvastatin (LDL-C −22.8% versus −8.6%; P <.01). The combination regimen had a safety and tolerability profile similar to that of atorvastatin alone.

Conclusions

The addition of ezetimibe to the starting dose of 10 mg/day of atorvastatin followed by response-based atorvastatin dose titration to a maximum of 40 mg/day provides a more effective means for reducing LDL-C levels in patients at high risk for CHD than continued doubling of atorvastatin as high as 80 mg/day alone.     

Detection of Campylobacter spp. in chicken fecal samples by real-time PCR

A real-time PCR assay for detecting thermophilic Campylobacter spp. directly in chicken feces has been developed. DNA was isolated from fecal material by using magnetic beads followed by PCR with a prealiquoted PCR mixture, which had been stored at -18 degrees C. Campylobacter could be detected in less than 4 h, with a detection limit of 100 to 150 CFU/ml, in a fecal suspension. A bacterial internal control was added before DNA extraction to control both DNA isolation and the presence of PCR inhibitors in the samples. The assay was performed on 111 swab samples from a Danish surveillance program and compared to conventional culturing using selective enrichment. There was no statistically significant difference in performance between real-time PCR and culture by selective enrichment, and the diagnostic specificity was 0.96 with an agreement of 0.92. Therefore, the assay should be useful for screening poultry flocks for the presence of Campylobacter.     

Flow cytometric analysis of platelet cyclooxygenase-1 and -2 and surface glycoproteins in patients with immune thrombocytopenia and healthy individuals

Immature platelets may contain more platelet enzymes such as cyclooxygenase (COX)-1 and COX-2 than mature platelets. Patients with immune thrombocytopenia (ITP) have a higher fraction of immature platelets and can therefore be utilized as a biological model for investigating COX-1 and COX-2 platelet expression. The aims were to develop flow cytometric assays for platelet COX-1 and COX-2 and to investigate the COX-1 and COX-2 platelet expression, platelet turnover, and platelet glycoproteins in ITP patients (n = 10) compared with healthy individuals (n = 30). Platelet count and platelet turnover parameters (mean platelet volume (MPV), immature platelet fraction (IPF), and immature platelet count (IPC)) were measured by flow cytometry (Sysmex XE-5000). Platelet COX-1, COX-2, and the glycoproteins (GP)IIb, IX, Ib, Ia, and IIIa were all analyzed by flow cytometry (Navios) and expressed as median fluorescence intensity. COX analyses were performed in both whole blood and platelet rich plasma (PRP), whereas platelet glycoproteins were analyzed in whole blood only. ITP patients had significantly lower platelet count (55 × 10⁹/L) than healthy individuals (240 × 10⁹/L, p < 0.01), but a higher MPV (p = 0.03) and IPF (p < 0.01). IPC was similar for the two groups (p = 0.74). PRP had significantly lower MPV (p < 0.01) and significantly higher platelet count and IPC (both p-values <0.03) when compared with whole blood. IPF was similar for PRP and whole blood (p = 0.18). COX-1 expression was 10 times higher and COX-2 expression was 50% higher in PRP than in whole blood (p_COX-1 < 0.01, p_COX-2 < 0.01). Platelet COX-1 expression was higher in ITP patients than healthy individuals using whole blood (p_COX-1 < 0.01) and PRP, though this was nonsignificant in PRP (p_COX-1 = 0.17). In ITP patients, positive correlations were found between platelet turnover and COX-1 expression (all p-values <0.01, rho = 0.80–0.94), whereas healthy individuals showed significant though weaker correlations between platelet turnover and COX-1 and COX-2 expressions (all p-values <0.03, rho = 0.44–0.71). GPIIb, IX, and Ib expression was increased in ITP patients compared with healthy individuals (all p-values < 0.03). GPIIb, IX, Ib, and IIIa showed positive correlations with platelet turnover in ITP patients (all p-values <0.02, rho = 0.71–0.94), but weak and nonsignificant correlations in healthy individuals (all p-values >0.14, rho = 0.11–0.28). In conclusion, ITP patients expressed higher COX-1 and platelet glycoprotein levels than healthy individuals. COX-1 and platelet glycoproteins demonstrated positive correlations with platelet turnover in ITP patients. In healthy individuals, COX-1 and COX-2 expression correlated positively with platelet turnover. PRP was more sensitive compared with whole blood as regards determination of COX. Therefore, PRP is the recommended matrix for investigating COX-1 and COX-2 in platelets.     

A double-blind, crossover study of Biotène Oralbalance and BioXtra systems as salivary substitutes in patients with post-radiotherapy xerostomia

This study assessed the efficacy of the Bioxtra (BX) and Biotène Oralbalance (OB) systems in the treatment of post-radiotherapy xerostomia. In a double-blind, crossover study, 20 patients with post-radiotherapy xerostomia were randomly allocated to receive either OB then BX, or vice versa, each product for 2 weeks, with a 1 week wash-out period in between. Subject-based dry mouth scores derived from 100-mm visual analogue scales were recorded at days 0 and 14 of each 2-week period, together with subjective perception of changes in dry mouth symptoms. Both treatments were effective, resulting in reduction of visual analogue scale scores from day 0-14. Between-groups comparisons identified that BX achieved significantly better improvements compared with OB for the perception of dry mouth and improvements in speech and was also rated as more pleasant to use than OB (P < 0.05). In conclusion, both treatments were effective in alleviating the symptoms of post-radiotherapy xerostomia, although BX achieved superiority in some of the outcomes assessed compared with OB.