Techniques and technologies to assess vascular calcification

Cardiovascular calcification (CV) is highly prevalent in chronic kidney disease stage V and has been associated with an increased risk for all-cause as well as cardiovascular mortality. A number of noninvasive imaging techniques are available to screen for the presence of CV-plain x-rays of the abdomen and extremities to identify macroscopic calcifications of aorta and peripheral arteries; echocardiography for assessment of valvular calcification; two-dimensional ultrasound for calcification of carotid arteries, femoral arteries and aorta, and computed tomography technologies that constitute the gold standard for quantification of coronary artery and aorta calcification. Some of these modalities are also useful to monitor calcification progression and to assess the effect of different therapeutic strategies directed at modifying calcification progression. In this article we review the strengths and limitations of the most common noninvasive techniques employed for the imaging of vascular calcification.     

Renal transplant in methylmalonic acidemia: could it be the best option?

Methylmalonic acidemia (MMA) is an inborn error of organic acid metabolism. Patients with severe disease develop many complications despite treatment; often, the disease progresses to severe damage of the central nervous system or to end-stage renal disease (ESRD). When medical treatment is ineffective, liver, kidney, or combined liver and kidney transplantation is advocated. At present, there are no definite guidelines as for the organ to be transplanted, and results are inconsistent. We report on a 27-year-old woman with MMA MUT⁰. The clinical symptoms developed at age 4 months. She progressed to ESRD and received a kidney transplant in November 1996 at age 17 years. One hundred and twenty months after transplant, renal function is normal; although urinary levels of methylmalonic acid are above normal limits, no episodes of metabolic decompensation have been observed after transplantation. Although liver is the major site of methylmalonyl-CoA mutase activity, this case and similar ones in the literature suggest that the smaller mutase activity present in the transplanted kidney may be sufficient to ensure partial correction of the metabolism of organic acids sufficient to prevent the onset of episodes of metabolic decompensation. It is worth investigating whether kidney transplant can be a safer and more satisfactory alternative to liver transplantation in cases of MMA unresponsive to medical treatment although urine MMA excretion remains significantly elevated. Source of financial support The study was made possible by an unrestricted grant from nuovArmonia nonprofit organization.     

Immunohistochemical analysis of human skeletal muscle AMP deaminase deficiency. Evidence of a correlation between the muscle HPRG content and the level of the residual AMP deaminase activity

We have previously described that, in healthy human skeletal muscle, an anti-histidine-proline-rich-glycoprotein (HPRG) antibody selectively binds to type IIB fibers that are well known to contain the highest level of AMP deaminase (AMPD) activity, suggesting an association of the HPRG-like protein to the enzyme isoform M. The present paper reports an immunohistochemical study performed on human skeletal muscle biopsies from patients with AMPD deficiency and carried out utilizing both the anti-HPRG antibody and an anti-AMPD antibody specific for the isoform M. A correlation between the muscle content of the HPRG-like protein and the level of AMPD activity was demonstrated. In the specimens from patients with Acquired AMPD deficiency the HPRG-immunoreactivity was less intense than that shown by the control subjects and was related to the residual AMPD activity. The patients affected by Primary and Coincidental AMPD deficiency, which were characterized by an absence of enzyme activity and AMPD immunoreactivity, showed the lowest HPRG immunoreactivity that was clearly detectable by Western blot analysis, but not by immunohistochemistry. The interpretation of the significance of these observations suggests a physiological mutual dependence between skeletal muscle HPRG and AMPD polypeptides with regard to their stability.Antonietta R.M. Sabbatini and Antonio Toscano contributed equally to this work.     

Cardiovascular imaging in patients with chronic kidney disease

Cardiovascular disease is highly prevalent in chronic kidney disease and has been associated with increased morbidity and mortality. Several morphological and functional tests are available to assess the cardiovascular system. Since structural and functional cardiovascular abnormalities have prognostic implications, their identification may become crucial for the implementation of effective preventive and therapeutic strategies. We review the most frequently used imaging methods to investigate structural and functional cardiovascular changes in patients with chronic kidney disease.     

Phenotypic heterogeneity in hereditary motor neuropathy type V: a new case report series

Previous studies have revealed a wide phenotypic heterogeneity in hereditary motor neuropathy type V in which upper and lower motor neurons and peripheral motor axons are variously affected, even within the same family. In this case series, we describe the genetic, clinical and electrophysiological features of patients belonging to a four-generation Italian family. Because of a possible anticipation phenomenon, the disorder became apparent at an earlier age as it passed to the next generation, with a median age of onset of 65?years for the first 2 generations, 32 for the third, and 13.5 for the fourth. The symptoms at onset varied considerably among the sufferers, with a predominant impairment of the hands in seven cases, the impairment of the four limbs in one patient and only of the lower limbs in another. Also muscle atrophy was variable, from very mild to severe (wasting of the distal muscles of the limbs). Moreover, electrophysiological results were heterogeneous, including cases with isolated and with diffuse axonal motor neuropathy, and one case of motor sensory polyneuropathy. A novel polymorphism G→T was also found in the Berardinelli-Seip congenital lipodystrophy 2 gene on intron 4. This broad phenotypic and genotypic spectrum calls the clinician attention to this rare and still insufficiently known disease.