Claudia D'Alessandro

Sarcolemmal excitability in myotonic dystrophy: Assessment through surface EMG

A motor point stimulation protocol was carried out on the tibialis anterior of myotonic dystrophy (MyD) patients. The surface myoelectric signal was monitored to record average rectified value (ARV), median frequency of power spectrum (MDF), and conduction velocity (CV) parameters. The ARV curve showed a decreasing trend that reveals a reduction in the M‐wave amplitude during stimulation. MDF presented a significant decrement in the first seconds of sustained contraction, probably caused by abnormal lengthening of the depolarization zone. CV was significantly lower in patients, suggesting reduced mean fiber size.

Food intake and nutritional status in stable hemodialysis patients.

This is a cross-sectional, multicenter, controlled study aiming to evaluate changes of actual dietary nutrient intake in 94 stable hemodialysis patients in respect to 52 normal subjects and guideline recommendations, and to assess the prevalence of signs of malnutrition. Energy and nutrients intake assessment was obtained by a three-day period food recall. Anthropometric and biochemical parameters of nutrition, bioelectric impedance vector analysis, and subjective global assessment (SGA) have been performed to assess nutritional status. SGA-B was scored in 5% of the patients. Body mass index < 20 Kg/m2, serum albumin <35 g/L, nPNA < 1.0 g/Kg, and phase angle <4.0° were detected in 16.3%, 16%, 23%, and 8.0 % of patients, respectively. HD patients showed a lower energy and protein intake in respect to controls, but no difference occurred when normalized per ideal body weight (29.3 ± 8.4 vs. 29.5 ± 8.4 Kcal/Kg i.b.w./d and 1.08 ± 0.35 vs. 1.12 ± 0.32 Kcal/Kg i.b.w. /d, respectively). Age was the only parameter that inversely correlates with energy (r = −0.35, p < 0.001) and protein intake (r = −0.34, p < 0.001). This study shows that in stable dialysis patients, abnormalities of nutritional parameters are less prevalent than expected by analysis of dietary food intake. Age is the best predictor of energy and protein intake in the dialysis patients who ate less than normal people, but no difference emerged when energy and protein intakes were normalized for body weight. These results recall the attention for individual dietetic counseling in HD patients, and also for a critical re-evaluation of their dietary protein and energy requirements.

Dialysis Exercise Team: The Way to Sustain Exercise Programs in Hemodialysis Patients

Patients affected by end-stage renal disease (ESRD) show quite lower physical activity and exercise capacity when compared to healthy individuals. In addition, a sedentary lifestyle is favoured by lack of a specific counseling on exercise implementation in the nephrology care setting. Increasing physical activity level should represent a goal for every dialysis patient care management. Three crucial elements of clinical care may contribute to sustain a hemodialysis exercise program: a) involvement of exercise professionals, b) real commitment of nephrologists and dialysis professionals, c) individual patient adaptation of the exercise program. Dialysis staff have a crucial role to encourage and assist patients during intra-dialysis exercise, but other professionals should be included in the ideal “exercise team” for dialysis patients. Evaluation of general condition, comorbidities (especially cardiovascular), nutritional status and physical exercise capacity are mandatory to propose an exercise program, in either extra-dialysis or intra-dialysis setting. To this aim, nephrologist should lead a team of specialists and professionals including cardiologist, physiotherapist, exercise physiologist, renal dietician and nurse. In this scenario, dialysis nurses play a pivotal role since they guarantee a constant and direct approach. Unfortunately dialysis staff may often lack of information and formation about exercise management while they take care patients during the dialysis session. Building an effective exercise team, promoting the culture of exercise and increasing physical activity levels lead to a more complete and modern clinical care management of ESRD patients.

Nutrition and Physical Activity in CKD patients

Chronic kidney disease (CKD) patients are at risk for protein-energy wasting, abnormal body composition and impaired physical capacity. These complications lead to increased risk of hospitalization, morbidity and mortality.In CKD patient as well as in healthy people, there is a close association between nutrition and physical activity. Namely, inadequate nutrient (energy) intake impairs physical performance thus favoring a sedentary lifestyle: this further contributes to loss of muscle strength and mass, which limit the quality of life and rehabilitation of CKD patients. In CKD as well as in end-stage-renal-disease patients, regular physical activity coupled with adequate energy and protein intake counteracts protein-energy wasting and related comorbidity and mortality. In summary, exercise training can positively influence nutritional status and the perception of well-being of CKD patients and may facilitate the anabolic effects of nutritional interventions.

Nephrolithiasis and hypertension: possible links and clinical implications

A definite epidemiological association exists between kidney stone disease and arterial hypertension, but the pathophysiological mechanisms are still not fully understood. Hypercalciuria or inflammation and oxidative stress have been proposed as possible links. However, there is more convincing evidence that the association between nephrolithiasis and hypertension may be considered as a part of the association between kidney stone disease, metabolic syndrome and atherosclerosis. From a clinical point of view, this association represents a crucial aspect of the clinical management of patients affected by kidney stone disease. In order to implement early prevention and treatment of cardiovascular and/or renal damage physicians should be encouraged to assess individual cardiovascular risk factors in any adult with kidney stones. Consequently, patients with kidney stones need a comprehensive approach rather than an intervention limited to the urinary tract and focused on stone resolution and recurrence prevention. It is time to view kidney stone disease as a systemic disorder, associated to or predictive of hypertension, chronic kidney disease, bone and cardiovascular damage. All these conditions negatively affect patient prognosis. This multi-systemic approach could increase the clinical impact of the kidney stone clinic.

Effect of telmisartan on the proteinuria and circadian blood pressure profile in chronic renal patients

Telmisartan is a type 1 angiotensin II (AT(1)) receptor blocker, effective and safe in the treatment of arterial hypertension. However, data with respect to circadian blood pressure (BP) monitoring and urinary protein (uP) excretion are lacking in normotensive or mild hypertensive patients with chronic renal diseases. This study has evaluated the effects of 80 mg telmisartan, given as monotherapy, on 24 h BP levels and uP loss in 16 non-diabetic patients affected by proteinuric renal disease. These patients did not meet the recommended values of mean BP, i.e. < 98 mmHg, when proteinuria was 0.5-1.0 g/d and mean BP < 92 mmHg, when proteinuria was 1-3 g/d. Patients with diastolic BP > 114 mmHg, nephrotic syndrome or severe renal failure (creatinine clearance < 20 ml/min) were excluded. After 4.2 +/- 2.7 month therapy, ambulatory BP monitoring showed a significant decrease (P < 0.001) of 24 h BP levels: systolic 135 +/- 11 vs. 122 +/- 13 mmHg, diastolic 84.4 +/- 8.1 vs. 75.9 +/- 8.5 mmHg, mean 101 +/- 8 vs. 91 +/- 9 mmHg. The effect was quite evident during either day-time or night-time. Clinic BP levels also significantly decreased (P < 0.001), and five patients reached the target values. uP excretion lowered by 37% (median) from 1.60 +/- 0.90 to 1.06 +/- 0.63 g/24 h (P < 0.01). No change in creatinine clearance (53.3 +/- 31.1 vs. 51.7 +/- 30.9 ml/min) or serum potassium level (4.3 +/- 0.3 vs. 4.4 +/- 0.4 mEq/l) was observed. Our results show that 80 mg of telmisartan, taken once daily, is effective in reducing uP excretion and BP throughout the 24 h, in normotensive or mild hypertensive renal patients. Since evidence exists that adequate control of BP, including during night-time, and reduction of proteinuria play a crucial role in the protection of renal function, telmisartan can be usefully considered in the conservative treatment of renal patients.

Non-Traditional Aspects of Renal Diets: Focus on Fiber, Alkali and Vitamin K1 Intake

Renal diets for advanced chronic kidney disease (CKD) are structured to achieve a lower protein, phosphate and sodium intake, while supplying adequate energy. The aim of this nutritional intervention is to prevent or correct signs, symptoms and complications of renal insufficiency, delaying the start of dialysis and preserving nutritional status. This paper focuses on three additional aspects of renal diets that can play an important role in the management of CKD patients: the vitamin K1 and fiber content, and the alkalizing potential. We examined the energy and nutrients composition of four types of renal diets according to their protein content: normal diet (ND, 0.8 g protein/kg body weight (bw)), low protein diet (LPD, 0.6 g protein/kg bw), vegan diet (VD, 0.7 g protein/kg bw), very low protein diet (VLPD, 0.3 g protein/kg bw). Fiber content is much higher in the VD and in the VLPD than in the ND or LPD. Vitamin K1 content seems to follow the same trend, but vitamin K2 content, which could not be investigated, might have a different pattern. The net endogenous acid production (NEAP) value decreases from the ND and LPD to the vegetarian diets, namely VD and VLPD; the same finding occurred for the potential renal acid load (PRAL). In conclusion, renal diets may provide additional benefits, and this is the case of vegetarian diets. Namely, VD and VLPD also provide high amounts of fibers and Vitamin K1, with a very low acid load. These features may have favorable effects on Vitamin K1 status, intestinal microbiota and acid-base balance. Hence, we can speculate as to the potential beneficial effects on vascular calcification and bone disease, on protein metabolism, on colonic environment and circulating levels of microbial-derived uremic toxins. In the case of vegetarian diets, attention must be paid to serum potassium levels.

Low vitamin K1 intake in haemodialysis patients

BACKGROUND & AIMS Vitamin K acts as a coenzyme in the γ-carboxylation of vitamin K-dependent proteins, including coagulation factors, osteocalcin, matrix Gla protein (MGP), and the growth arrest-specific 6 (GAS6) protein. Osteocalcin is a key factor for bone matrix formation. MGP is a local inhibitor of soft tissue calcification. GAS6 activity prevents the apoptosis of vascular smooth muscle cells. Few data on vitamin K intake in chronic kidney disease patients and no data in patients on a Mediterranean diet are available. In the present study, we evaluate the dietary intake of vitamin K1 in a cohort of patients undergoing haemodialysis. METHODS In this multi-centre controlled observational study, data were collected from 91 patients aged >18 years on dialysis treatment for at least 12 months and from 85 age-matched control subjects with normal renal function. Participants completed a food journal of seven consecutive days for the estimation of dietary intakes of macro- and micro-nutrients (minerals and vitamins). RESULTS Compared to controls, dialysis patients had a significant lower total energy intake, along with a lower dietary intake of proteins, fats, carbohydrates, fibres, and of all the examined minerals (Ca, P, Fe, Na, K, Zn, Cu, and Mg). With the exception of vitamin B12, vitamins intake followed a similar pattern, with a lower intake in vitamin A, B1, B2, C, D, E, folates, K1 and PP. These finding were confirmed also when normalized for total energy intake or for body weight. In respect to the adequate intakes recommended in the literature, the prevalence of a deficient vitamin K intake was very high (70-90%) and roughly double than in controls. Multivariate logistic model identified vitamin A and iron intake as predictors of vitamin K deficiency. CONCLUSIONS Haemodialysis patients had a significantly low intake in vitamin K1, which could contribute to increase the risk of bone fractures and vascular calcifications. Since the deficiency of vitamin K intake seems to be remarkable, dietary counselling to HD patients should also address the adequacy of vitamin K dietary intake and bioavailability. Whether diets with higher amounts of vitamin K1 or vitamin K supplementation can improve clinical outcomes in dialysis patients remains to be demonstrated.

Hypoproteic diet in patients' community: reports from University of Pisa

Nutrition is considered by the National Health Authorities as part of the clinical care process. In this perspective, the catering service of a hospital represents a powerful therapeutic and educational aid for the in-patients. The catering service of our University Hospital in Pisa is based on a collection of standardized diets with indications concerning the type of patient which they are addressed. The present paper deals with our experience in this field, and in particular with the diets for renal patients. The so called “special” diets, such as low protein (0.6 g / kg b. w. / day) low phosphorus diet, the low protein (0.7 g / kg b.w./ day) vegetarian diet and the very low protein (0.3 g / kg b. w./day) low phosphorus diet are prescribed by the doctors and developed by the dietician for the individual patient. Since its preparation, the low-protein diets have several critical points, namely processing - packaging and distribution of the diet, no customization, the low protein artificial foods). In order to improve the service, we have detected the food actually consumed and the pleasantness of low-protein meals using two survey sheets given to patient during their hospitalization. Overall, the results indicate a good acceptance of diets by patients, but with a reduced consumption of low protein food, bread in particular.

La calcolosi renale infetta e la calcolosi renale con infezione: terapia preventiva, in particolare post-chirurgica

rich Christoph Gottfried von Struve, un diplomatico con la grande passione per i minerali. La struvite è una forma di calcolosi infetta che consegue all’infezione delle vie escretrici da parte di germi capaci di produrre un enzima non presente nell’uomo: l’ureasi. L’ureasi di derivazione batterica idrolizza l’urea presente nelle urine in ammoniaca ed anidride carbonica che, reagendo con l’acqua, danno origine alla formazione di ioni ammonio e bicarbonato, con conseguente elevazione del pH. Si determina così una condizione unica, non presente in fisiologia e caratterizzata da una elevata concentrazione di ioni ammonio in presenza di pH alcalino, che conduce alla nucleazione del triplo fosfato di ammonio e magnesio e carbonato apatite, sale mai presente nelle urine normali (4). Dei patogeni responsabili delle infezioni delle vie urinarie, quelli produttori di ureasi sono Providencia R, Morganella M, Proteus V e Klebsiella P in oltre il 95% dei casi; seguiti da Yersinia E, Stafilococco A e Proteus M nel 90% dei casi e da Enterobacter spp (50%), Pseudomonas A (33%), mentre nel caso della Escherichia coli solo l’1% dei ceppi produce l’ureasi. Contrariamente a quanto sarebbe logico aspettarsi, il riscontro di sepsi urinaria nel paziente con calcolosi di struvite non è un reperto costante nella pratica clinica. Nello studio di Hakagashi et al (5), la positività dell’urinocoltura veniva riscontrata solo nel 20% delle calcolosi di struvite, con una positività dell’esame microbiologico del calcolo che arrivava fino al 50% dei casi. Questa “strana” negatività dell’esame colturale, potrebbe essere giustificata da una bassa carica microbica o dalla presenza di un “biofilm”. Il biofilm è costituito da aggregati batterici inglobati in una matrice di polisaccaridi, prodotta dai batteri stessi, in grado di aderire sia ai tessuti biologici sia a materiali sintetici, e che conferiscono ai germi la capacità di sopravvivere in ambienti ostili. Molte infezioni croniche risultano, infatti, difficilmente eradicabili La calcolosi renale infetta, o di struvite, è una forma meno frequente rispetto a quella calcica o di acido urico, ma è molto più aggressiva e può essere responsabile di progressione verso l’insufficienza renale. Tuttavia qualsiasi tipo di litiasi, in particolare se recidivante e/o complicata da uropatia ostruttiva o da infezione, può costituire una potenziale causa di danno parenchimale renale irreversibile. Nello studio retrospettivo di Jungers (1), riguardante 1391 pazienti incidenti in dialisi tra il 1989 ed il 2000, la calcolosi renale rappresenta la malattia di base nel 3.2% dei casi; in questo gruppo di pazienti, la calcolosi di struvite era presente nel 42% dei pazienti, la calcolosi calcica nel 26.7%, quella urica nel 17.7%, mentre il 13% dei pazienti era affetto da una forma ereditaria di nefrolitiasi. È noto che la calcolosi renale è un fattore di rischio di infezione urinaria che, a sua volta, favorisce la formazione di calcoli. Quindi la sepsi urinaria e la calcolosi renale sono due patologie che possono auto-alimentarsi in un vero e proprio circolo vizioso di non facile trattamento. La presenza di infezione è stata riportata nel 32% delle calcolosi di ossalato di calcio (2), mentre Mariappan et al (3) hanno riportato come nel 25% dei casi di uropatia ostruttiva si riscontrasse la presenza di infezione del calcolo, e che un’infezione del tratto urinario a monte dell’ostruzione era presente fino al 66% dei casi. Quando a colonizzare le vie escretrici sono germi ureasi-produttori, è l’infezione stessa che causa modificazioni della composizione delle urine tali da portare alla formazione di cristalli e quindi di calcoli di triplo fosfato di ammonio e magnesio e carbonato apatite, sale anche chiamato “struvite”. Il termine “struvite” fu coniato nel 1920 dal chimico Georg Ludwig Ulex in onore di HeinLa calcolosi renale infetta e la calcolosi renale con infezione: terapia preventiva, in particolare post-chirurgica