Development of a thermal test object for the measurement of ultrasound intracavity transducer self-heating

The elevated surface temperature of diagnostic ultrasound transducers imposes an important limitation to their safe use in clinical situations. Moreover, particular care should be taken if transvaginal transducers are to be used during routine scans in the first few weeks of pregnancy as the transducer surface can be very close to embryonic/fetal tissues. Published results have shown that the heating of tissue due to transducer self-heating can equal and often exceed the acoustic heating contribution. In this article, we report the development of a portable self contained thermal test object (TTO) capable of assessing the self-heating of intracavity diagnostic ultrasound transducers. The thermal conductivity and volumetric heat capacity of the tissue mimicking material (TMM) used in the TTO were measured, yielding values of (0.56 +/- 0.01) W m(-1) K(-1) and (3.5 +/- 0.8) MJ m(-3) K(-1). The speed of sound of the TMM was measured as 1540 m s(-1) and the attenuation over a frequency range of 2 to 10 MHz was found to be (0.50 +/- 0.01) dB cm(-1) MHz(-1). These results are in excellent agreement with the International Electrotechnical Commission (IEC 60601-2-37) requirements and the previously published properties of biological soft tissue. The temperature stability and uniformity, and suitability of the TTO for the measurement of transducer self-heating were tested and found to be satisfactory. The TTO reached a stable temperature of 37 degrees C in 3 h and the spatial variation in temperature was less than +/- 0.2 degrees C. Lastly, transducer self-heating measurements from a transvaginal transducer exceeded the IEC temperature limit of 43 degrees C in less than 5 min and the temperature reached after 30 min was 47.3 degrees C.     

Effect of Salinity on Biodegradation of Polycyclic Aromatic Hydrocarbons (PAHs) of Heavy Crude Oil in Soil

The spillage of crude oil in the soil damages the environment. Polycyclic aromatic hydrocarbons (PAHs) are one of the crude oil components that may be harmful for living organisms. PAHs can disappear from the environment by volatilization and biodegradation. The effect of different NaCl concentrations (0%–5%) on PAHs reduction from the heavy crude oil-contaminated soil was studied. Our results showed that increasing NaCl concentration in soil had decreasing effect on total crude oil and PAHs reduction. The biodegradation of total crude oil was higher in 0% NaCl (41%) while higher total PAHs reduction was observed in 1% NaCl (35%). The lower total crude oil and PAHs reduction were observed in 5% NaCl (12% and 8% respectively). Phenanthrene, anthracene and pyrene reduction were higher in 1% NaCl, while fluoranthene and chrysene reduction were higher in 0% NaCl.     

Serum Bactericidal Antibody Response 1 Year after Meningococcal Polysaccharide Vaccination of Patients with Common Variable Immunodeficiency

Some patients with common variable immunodeficiency (CVID) can generate an antibody response following vaccination with Neisseria meningitidis polysaccharide, but the duration of this protection is unknown. In this study, serum bactericidal antibody (SBA) responses to serogroup C N. meningitidis of 23 patients with CVID and 23 sex- and age-matched controls were measured 1 year after vaccination with the plain A/C meningococcal polysaccharide vaccine. The fold rise in serum bactericidal antibody geometric mean titers of the control group from prevaccination to 1 year postvaccination was significantly higher than that of the patient group (5.41- versus 2.96-fold, P = 0.009). Of 23 CVID patients, 8 had a poor response to vaccine (<4-fold rise) 3 weeks after vaccination, and low titers remained when measured 1 year later. Of the 15 CVID patients who had a normal response to vaccine (≥4-fold rise) 3 weeks after vaccination, 6 cases failed to maintain protective SBA titers, whereas the remaining 9 had protective titers 1 year after vaccination. Only one of the 23 controls, who developed protective SBA titers after 3 weeks, lost the protective titers after 1 year. Among the patients, the presence of bronchiectasis and/or splenomegaly at enrollment was associated with poor SBA response to vaccine at 3 weeks and/or failure to maintain protective levels at 1 year. The results of this study demonstrate that a number of CVID patients can produce protective antibody titers that can persist for 1 year after vaccination, which lends strong support to the inclusion of polysaccharide vaccine in the immunization program for CVID patients.Common variable immunodeficiency (CVID) is the commonest symptomatic primary immunodeficiency disease and is a heterogeneous group of disorders, characterized by severe reduction of serum levels of IgG and IgA, with normal or low numbers of B cells in the absence of any recognized genetic abnormality (2, 11, 16, 30). Patients with CVID usually experience recurrent bacterial infections (1, 14) and carry an increased risk of autoimmunity (12, 28) and malignancies (4, 24). Various defects of B cells, T cells, and dendritic cells have been reported for CVID (26, 29, 34-36); however, the exact pathophysiology of the disease is still unclear (3, 15).Deployment of polysaccharide and protein vaccines in CVID is a subject of active debate. Although it is intuitive that CVID patients should have poor antibody responses to vaccine, it is apparent that some patients can produce normal antibody titers (5, 18, 21, 32, 33). We have reported that a protective antibody response was achieved 3 weeks following vaccination with polysaccharide meningococcal vaccine of a group of CVID patients (32, 33). In the current study, we measured serum bactericidal antibody (SBA) titers (7) of the same cohort of patients 1 year after the initial vaccination.     

Numerical and Clinical Accuracy of a Continuous Glucose Monitoring System during Intravenous Insulin Therapy in the Surgical and Burn Intensive Care Units

Background

Intensive insulin therapy (IIT) for glycemic control in critically ill patients has been shown to be beneficial. Continuous glucose monitoring systems (CGMSs) have been approved as an adjunct to complement standard glucose monitoring in type 2 diabetes mellitus. This study was designed to evaluate the accuracy of a real-time CGMS (DexCom^TM STS) in the intensive care unit (ICU). We also evaluated its reliability and accuracy using a hyperinsulinemic-euglycemic and a hyperglycemic clamp study.

Methods

Nineteen patients were enrolled in this 7-day study [13 = surgical intensive care unit (SICU), 6 = burn intensive care unit (BICU)]. The patients were on IIT for at least 2 h prior the subcutaneous sensor insertion. Mean age and body mass index for SICU and BICU patients were 60.3 ± 3.7 and 64.5 ± 6.2 years and 36.6 ± 5.0 and 33.85 ± 3.4 kg/m2, respectively. DexCom accuracy was analyzed separately for the Johnson & Johnson (J&J) calibration finger sticks, Roche Accucheck finger sticks, and the Hitachi 917 analyzer measurements on serum using Clarke error grid analysis and Bland–Altman analysis. In the clamp studies, 20 patients were enrolled, and the data were analyzed similarly.

Results

There were 1065 pairs of DexCom–Accucheck, 232 pairs of DexCom–J&J, and 84 pairs of DexCom–Hitachi in ICU patients. For DexCom–Accucheck, 68.26% of the pairs fell into zone A, 31.83% into zone B, and 0.75% into zone C. There were no values in zones D or E.From the 1102 matching DexCom–Beckman pairs in clamp studies, 42.29% were in zone A, 55.90% were in zone B, and 4.08% were in zone C.

Conclusions

Despite the high percentage of measurements in zones A and B, underestimation of hypoglycemia by DexCom measurements makes it an unreliable device in the ICU setting.     

Epidemiology of upper gastrointestinal cancers in Iran： A Sub site analysis of 761 cases

AIM： To define the sub site distribution of upper gastrointestinal cancers in three provinces of Iran.
METHODS： The study was carried out in three provinces in Iran： Ardabil, Golestan, and Tehran. In Arbabil and Golestan, the data was collected from the sole referral center for gastrointestinal cancers and the local cancer registry. For Tehran province, data from two major private hospitals were used. All gastric and esophageal cancer patients diagnosed during the period from September 2000 and April 2002 were included in the study.
RESULTS： A total of 761 patients with upper gastrointestinal cancers were identified, 314 from Ardabil, 261 from Golestan, and 186 from Tehran. In Tehran, the relative rate of cancer increased from the upper esophagus to the distal stomach. In Golestan, the reverse pattern was observed. In Ardabil, the mid portion （distal esophagus and proximal stomach） was involved most frequently.
CONCLUSION： There were considerable variations in the sub site of upper gastrointestinal cancers in the three provinces studied, We cannot provide any explanation for this variation, Further research aimed at explaining the discrepancies in sub site distribution of upper gastrointestinal cancers may help identify important risk factors.     

Local paclitaxel delivery after coronary stenting in an experimental animal model

The goal of this study was to test the safety and efficacy of local paclitaxel delivery via a newly designed application catheter in an experimental animal study. Drug-eluting stents reduce restenosis in comparison to bare-metal stents. The drug-eluting polymer, however, may exert potential thrombogenic and inflammatory effects. A catheter-based local paclitaxel delivery offers further advantages, particularly a homogenous drug transfer into the vessel wall and a pharmacotherapy of the stent edges. In 30 pigs, both bare-metal stent (3.0 x 13 mm) implantation and balloon angioplasty were performed. Ten pigs received subsequent local delivery of paclitaxel-solution via a newly designed catheter (Genie, ACROSTAK corp., Switzerland), 10 animals served as a sham group and received vehicle (0.9% NaCl solution) and 10 animals were used as a control group. All animals were treated with aspirin and clopidogrel to prevent stent thrombosis. After final angiography the vessels were excised 42 days after intervention and prepared for histological and histomorphometric analysis. All coronary arteries showed complete endothelialization 42 days following treatment. Paclitaxel treatment led to a marked reduction of neointimal proliferation either post stent implantation (neointimal area: 1.04 +/- 0.10 mm(2) vs. 2.37 +/- 0.23 mm(2), p < 0.001) or post balloon dilatation (neontimal area: 0.35 +/- 0.14 mm(2), vs. 0.68 +/- 0.24 mm(2), p < 0.01). There were no significant angiographic or histomorphometric differences between the control and the sham group. In both paclitaxel groups neither angiographic edge phenomena nor a significant histomorphometric inflammatory response were found in the treated vessel segments. In conclusion, the local application of paclitaxel via the Genie catheter is safe and effective to significantly reduce the proliferative response post-stent implantation or balloon dilatation in an experimental animal model.     

Genetic polymorphisms in three Iranian populations with different risks of esophageal cancer, an ecologic comparison

The age-standardized incidence of esophageal cancer (EC) varies from 3 to >100/100,000 per year in different provinces of Iran. This striking variation of incidence is associated with differences in ethnic backgrounds, raising the possibility that genetic factors are involved in the pathogenesis of EC. We compared the frequencies of polymorphisms in ten genes that have been hypothesized to have a role in risk of EC (CYP1A1, CYP2A6, CYP2E1, GSTM1, GSTP1, GSTT1, ADH2, ADH3, ALDH2, and O6-MGMT) among three Iranian ethnic groups with highly varying rates of EC. These three groups included high-risk Turkomans, medium-risk Turks, and low-risk Zoroastrian Persians. Compared to Zoroastrians, Turkomans had higher frequency of four alleles that are speculated to favor carcinogenesis (CYP1A1 m1, CYP1A1 m2, CYP2A6*9, and ADH2*1); these results are consistent with an influence of these allele variants on the population risk of EC. However, none of these four alleles had a high enough prevalence in Turkomans to explain the high rates of EC in this group. Three of these four alleles (CYP1A1 m1, CYP1A1 m2, CYP2A6*9) were less frequent among Turkomans than in some Asian populations with lower risks of EC. We conclude that it is unlikely that variations in these polymorphic genes are major contributors to the high incidence of EC among Turkomans in Iran.