Management of atherosclerotic renovascular disease: the effect of renal artery stenting on renal function and blood pressure

In the last few years, renal artery stenting has gradually evolved into one of the most important therapeutic modalities in the management of atherosclerotic renovascular disease. Stenting is nowadays preferred by a steadily increasing number of physicians, not only because of its significant contribution to blood pressure control, but also because of its documented ability to maintain, and even improve, renal function. At the same time, procedure-related morbidity and mortality rates are extremely low, while recurrent stenosis rates have been repeatedly reported to be␣minimal. Percutaneous transluminal renal angioplasty (PTRA) and stenting are nowadays considered by many physicians to be the treatment of choice for atherosclerotic renovascular disease.     

Influence and critique of CREST and ICSS Trials

The principle findings of the Carotid Revascularization Endarterectomy Versus Stenting Trial and the International Carotid Stenting Study are reviewed and discussed. Flaws and possible weaknesses in both trials are highlighted. The possibility that some Carotid Revascularization Endarterectomy Versus Stenting Trial conclusions have been misinterpreted in ways not justified by the trial's data is considered. This possibility may have prompted one conclusion of a recent American Heart Association Guideline on the management of carotid artery disease to be misleading.     

Angular measurement error due to different measuring devices

BACKGROUND: Angular measurements are commonly used in orthopaedic surgery. No study has addressed measurement variability due to the measurement device itself. It was the purpose of this study to assess measurement variability of articulated versus fixed devices. METHODS: Three articulated and 4 fixed goniometers were randomly selected. Thirty-two different angles, ranging from a few degrees to nearly 180 degrees, were drawn with a standard soft-lead marking pencil. The angles were measured by 5 different observers with 7 different goniometers on 2 separate occasions separated by a minimum of 3 weeks. We wished to determine whether the variability of any goniometer was within a +/-1-degree range. RESULTS: There were 1023 (91.3%) absolute differences of 1 degree or less and 97 (8.7%) of more than 1 degree. Intraobserver agreement was 92.0%; 96.9% for fixed and 84.0% for hinged goniometers. Interobserver agreement was of 90.7%; 96.2% for the fixed and 83.4% for the hinged goniometers. Intragoniometer agreement was 91.3%; 96.9% for fixed and 84.0% for hinged goniometers. Intergoniometer agreement was 87.0% with fixed goniometers demonstrating better agreement than hinged goniometers. The overall intraobserver and interobserver measurement variability was +/-2.33 and +/-2.26 degrees, respectively; the overall intragoniometer and intergoniometer measurement variability was +/-2.26 and +/-2.30 degrees, respectively. For fixed goniometers, the intergoniometer measurement variability is +/-2.0 degrees, for hinged goniometers, +/-2.9 degrees, and when using both fixed and hinged goniometers, +/-2.4 degrees. Thus, the fixed goniometers are the ideal type with overall better agreement and measurement variability. CONCLUSION: Any one orthopaedic surgeon should use the same goniometer at all times, preferably a fixed type, so that measurement variability can be reduced by +/-2.0 degrees. If a physician uses a particular published measurement variability from the literature in which different goniometers were used, then the intraobserver measurement variability will be less than the published value by approximately +/-2 degrees. This is important when faced with the question of a change in an angular measurement being a true change or simply a reflection of measurement error.     

Statins exert multiple beneficial effects on patients undergoing percutaneous revascularization procedures

BACKGROUND AND AIMS: Statins are an essential component of the therapeutic approach of patients with atherosclerotic disease. Statin use is also associated with improved peri-operative and long-term outcomes in these patients. We aimed to define the role of statin treatment in patients undergoing percutaneous revascularization procedures. LITERATURE SEARCH METHOD: We searched Medline for studies assessing the effect of statin treatment on percutaneous interventions. LITERATURE SEARCH RESULTS: Early statin treatment is associated with improved outcomes in patients undergoing percutaneous coronary intervention procedures. Current evidence implies that statin treatment may also play a beneficial role in the management of patients undergoing percutaneous renal artery revascularization and endovascular abdominal aortic aneurysm repair, carotid angioplasty/stenting and endovascular peripheral arterial interventions. CONCLUSIONS: Preliminary data suggest that statins exert multiple beneficial actions in patients undergoing percutaneous interventions. Future randomized trials are expected to further evaluate the beneficial effects of statins in these procedures.     

Rheological Study of Synovial Fluid Obtained from Dogs: Healthy,Pathological, and Post-Surgery,after Spontaneous Rupture of Cranial Cruciate Ligament

In the present study synovial fluid (SF) obtained from the stifle joint of healthy adult dogs and of dogs after cranial cruciate ligament rupture was analyzed regarding its rheological characteristics according to the condition of the joint. The viscoelastic and shear flow properties were measured at 25 and 38 °C. The results showed that the healthy SF exhibits practically temperature independent viscosity curve and satisfactory viscoelastic characteristics, i.e. G′ > G′′, over frequencies of 0.05–5 Hz, and characteristic relaxation time λ of the order of magnitude of 100 s. Creep measurements demonstrate that the zero shear viscosity was in the range of 10–100 Pa s. In shear flow viscosity measurements, by increasing [(g)\dot] \dot{\gamma } from 10⁻⁴ s⁻¹ up to 10³ s⁻¹, non-Newtonian shear thinning behavior was observed and the viscosity values were decreased from 10³ to 0.1 Pa s. On the contrary, in pathological conditions of cranial cruciate ligament rupture (CCLR), the measured viscosity was found drastically reduced, i.e. between 100 and 10 mPa s. The CCLR synovial fluid, similar to healthy SF, exhibits insignificant temperature dependence. The present study showed also that about one week after a surgery for CCLR repair the SF exhibits non-Newtonian behavior of dilute polymers. After two weeks from the operation, however, the rheological behavior converges to the one of healthy SF.     

Do different vascular risk factors affect all arteries equally?

Established vascular risk factors (ie, smoking, hypertension, diabetes mellitus, and dyslipidemia) play an important role in the development of vascular disease. Emerging evidence suggests that some of these risk factors may have a more intense effect on specific arterial beds, a finding that holds implications for a prognostic role for certain types of vascular disease.     

Monte Carlo simulations of drug release from matrices with periodic layers of high and low diffusivity

We have studied drug release from matrices with periodic layers of high and low diffusivity using Monte Carlo simulations. Despite the fact, that the differential equations relevant to this process have a form that is quite different from the classical diffusion equation with constant diffusion coefficient, we have found that the Weibull model continues to describe the release process as well as in the case of the "classical" diffusion controlled drug release. We examine the similarities and differences between release from matrices with periodic layers and matrices with random mixtures of high and low diffusivity area and show that the periodic geometrical arrangement of the low diffusivity areas has an influence in the release profile which is negligible for low diffusivity ratios, but becomes important in the case of high diffusivity ratios and for intermediate values of the periodic "length". Such an arrangement in periodic layers leads to Weibull exponent a which are lower than those of the corresponding random arrangement and exponents b which are higher than those of the random case.     

Origin and diversification of the clonogenic cell in multiple myeloma: lessons from the immunoglobulin repertoire.

The study of immunoglobulin genes in multiple myeloma over the last decade has provided important information regarding biology, ontogenetic assignment, disease evolution, pathogenic consequences and tumor-specific therapeutic intervention. Detailed analysis of VH genes has revealed the clonal relationship between switch variants expressed by the bone marrow plasma cell and myeloma progenitors in the marrow and peripheral blood. Regarding VH usage, a bias was found against the V4-34 gene encoding antibodies with cold agglutinin specificity (anti-I/i), thus explaining in part the absence of autoimmune phenomena in myeloma compared to other B cell lymphoproliferative disorders. However, in some studies a substantial number of cases analyzed were carrying the rearranged Humkappav325 Vkapppa gene, known to be over utilized by B cell chronic lymphocytic leukemia clones and possessing autoantibody binding activity. VH genes accumulate somatic hypermutations following a distribution compatible with antigen selection, but with no intraclonal heterogeneity. The analysis of Vkappa genes indicates a bias in usage of Vkappa family members; somatic hypermutation, in line with antigen selection, of the expressed Vkappa genes is higher than any other B cell lymphoid disorder. Similar conclusions were reached for Vlambda genes; in this case, the analysis raises the controversial issue of N nucleotide insertion at Vlambda-Jlambda junctions, apparently as a result of TdT activity. A complementary imprint of antigen selection as evidenced by somatic hypermutation of either the VH or VL clonogenic genes has been observed. The absence of ongoing somatic mutations in either VH or VL genes gives rise to the notion that the cell of origin in myeloma is a post-germinal center memory B cell.