Coexistence of renal replacement lipomatosis with xanthogranulomatous pyelonephritis

We report on a case of coexistence of replacement lipomatosis with xanthogranulomatous pyelonephritis (XGP) in the same kidney associated with staghorn calculi. A 63-year-old man was admitted to hospital complaining of a right abdominal mass. Computed tomography (CT) showed renal parenchymal atrophy with extremely increased perirenal fat. Right nephrectomy was performed. Postoperative diagnosis was renal replacement lipomatosis with XGP. Renal replacement lipomatosis and XGP have several similarities in terms of clinical background and CT findings. Sometimes it is difficult to differentiate them from malignant diseases. It is extremely rare that both conditions coexist in the same kidney. To our knowledge, only one such case has been reported.     

STUDIES ON PEPTIDES

The tetradecapeptide amide corresponding to the entire amino acid sequence of a wasp venom (polistes mastoparan), isolated from Polistes jadwagae, was synthesized using the trifluoroacetic acid-thioanisole deprotecting procedure.     

Very high doses of valsartan provide renoprotection independently of blood pressure in a type 2 diabetic nephropathy rat model

Aim:   Angiotensin II type 1 receptor blockers (ARB) retard the progression of hypertensive diabetic kidney disease. Clinical evidence suggests that the dose of ARB required to correct hypertension is suboptimal for renoprotection evaluated by proteinuria. No systematic, prospective study has yet evaluated separately the effect of increasing doses of ARB on blood pressure and proteinuria.
Methods:   Over a period of 8 weeks, the effect of seven constant doses of an ARB, valsartan (4–160 mg/kg per day), on blood pressure and proteinuria taken as a surrogate marker of nephropathy in a hypertensive, type 2 diabetic rat model, the spontaneously hypertensive/NIH-corpulent rat (SHR/NDmcr-cp), was assessed. In this spontaneously hypertensive rat strain, a genetic mutation in the leptin receptor gene is associated with hyperphagia leading to obesity with metabolic syndrome and eventually to nephropathy.
Results:   No additional blood pressure lowering was observed above 120 mg/kg per day of valsartan, suggesting that a dose of 80–120 mg/kg per day had a maximal effect. Nevertheless, higher doses of valsartan further reduced proteinuria in a dose-dependent fashion suggesting the absence of a maximal dose. Obesity, hyperglycaemia and hypercholesterolaemia were unaffected but hypertriglyceridaemia was partially corrected at various ARB doses.
Conclusion:   ARB improve renoprotection at doses above those required for a maximal effect on blood pressure. The mechanism of the renoprotection obtained at high doses of ARB is yet to be elucidated.     

Heart Rate Variability in Patients with Familial Amyloid Polyneuropathy

The purpose of this study was to evaluate heart rate variability (HRV) in patients with familial amyloid polyneuropathy (FAP) using the time- and frequency-domain analysis. The study population consisted of 19 patients with FAP, and 19 age and sex matched normal volunteers. The 24-hour Holter recordings of all subjects in sinus rhythm and off medication were analyzed. Five time-domain indices of HRV were computed. The frequency component of HRV was calculated by fast Fourier transform analysis of the RR intervals. The power spectrum of the low frequency (LF) between 0.04–0.15 Hz and high frequency (HF) between 0.15–0.40 Hz and the LF/HF ratio was calculated. Global measures of HRV including the standard deviation of the mean of RR intervals (SDNN) and the standard deviation of 5-minute mean RR intervals (SDANN) were decreased in patients with FAP. Specific vagal influences on HRV including the proportion of RR intervals more than 50 milliseconds different (pNN50) and the HF power on spectral analysis were less in patients with FAP. LF power and LF/HF ratio were more decreased in patients with FAP at the advanced stage than at the early stage. In conclusion, HRV was significantly decreased in patients with FAP at the early stage, and sympathetic activity was more decreased in patients at the advanced stage. These findings suggest that the decrease of the HRV is an indicator of this disease and the power spectral analysis of the HRV is beneficial in assessing the severity of the autonomic dysfunction.     

Kinetic study of racemization of aspartyl residues in model peptides of αA-crystallin

We have reported that two aspartyl (Asp-151 and Asp-58) residues in αA-crystallin in human eye lens were inverted to the D-isomer and isomerized to β-aspartyl residues with age. We report here the kinetics of the Asp racemization of three model peptides corresponding to fragments of αA-crystallin: IQTGLD¹⁵¹ATHAER (T18 peptide). TVLD⁵⁸SGISEVR (T6 peptide) and HFSPED⁸⁴LTVK (T10 peptide, as a control). The rate constants of the racemization of Asp residues in these peptides were measured at pH 7.0. at five temperatures: 50, 60, 70, 80 and 90 °C. From the Arrhenius equation, we estimated the activation energy (E) of racemization and the time required for the Asp D/L ratio to approximate to 1.0 (D/L ratio of Asp = 0.99) at body temperature. For the peptide T18, E=21.4 kcal/mol and t=13.5 yr. For the peptide T6, E= 26.8 kcal/mol and t= 49.5 yr. For the control peptide T10, E=28.3 kcal/mol and t= 78.1 yr. The racemization rate of Asp in these three peptides is parallel to that of Asp residues in αA-crystallin. The racemization rate of Asp in the T18 peptide was very rapid compared to that in the other peptides. This result also reflects the racemization rate in native αA-crystallin