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In RDT patients hemocoagulative changes are repeatedly found; of these the most important are platelets' functional defects. Biochemical and biophysical modifications responsible for this pathology have not been completely clarified. In 20 non-thrombocytopenic patients, dialyzed 3 times weekly for over 1 year, we evaluated, using standard methodology, platelet adhesivity and aggregation induced by collagen and ADP at varying dosages. All blood samples were collected after the longest interdialytic period and just before dialysis. At the same time we evaluated the basic metabolic pool and, after collagen stimulation, the intraplatelet functional storage pool of ATP and ADP. The dosages were obtained using simple, reproducible and modern bioluminescence technique, which utilises microorganism light emission (bioluminescence) due to the oxidation of the bacterial substrate by catalyzing enzyme (luciferase) (1251 Luminometer LKB). We compared this data with that obtained from 40 healthy subjects. In the patients examined, adhesivity and aggregation result altered. The intraplatelet content of all nucleotides in both pools is significantly reduced if compared to the control group. The ATP and ADP concentration of both metabolic and functional pools cannot be correlated to the following: serum creatinine, BUN, calcemia, PTH, Hb. On the contrary we found that basal metabolic ATP values are inversely related (p less than 0.01) to serum phosphate levels. An analysis of results of this preliminary study leads us to hypothesize that hyperphosphatemia could interfere with intraplatelet glycolysis inducing a reduction of intracellular ATP. As all platelet functions are ATP and ADP dependent, we could consider the nucleotide deficit a cause of "uraemic platelet" disfunction, not modifiable with RDT but perhaps only through an appropriate control of phosphate levels.

The addition of sulphite to rat-liver mitochondria (RLM) causes an uptake of H+ that is unaffected by NEM and butylmalonate. The uptake of H+ induced by sulphate or thiosulphate is abolished by NEM and butylmalonate in freshly isolated RLM, whereas it is inhibited only by butylmalonate in sulphite-pretreated mitochondria. The data suggest that sulphite is cotransported with H+, whereas the movement of H+ associated to the uptake of sulphate or thiosulphate by RLM is mediated by either phosphate or sulphite.

Publisher Summary The tricarboxylate transport protein can be purified approximately six fold by chromatography on hydroxylapatite with a recovery of 50% of the activity present in the submitochondrial particles (SMP) extract. The presence of cardiolipin (DPG) during extraction and purification is required for optimal activity of the reconstituted tricarboxylate carrier. This chapter presents the activity of the reconstituted citrate/citrate exchange of the extracts from liver SMP and of the eluates obtained from HTP, both in the presence and in the absence of DPG. Absorption chromatography on HTP increases the specific activity several fold, with a recovery of the total activity of 50%. Inclusion of DPG in the solubilization medium does not influence the enhancement in purification, but increases the activity of citrate exchange both in the extracts and in the HTP eluates. A similar increase in the activity of the mitochondrial phosphate carrier in the HTP eluate as been observed and it has been suggested that DPG prevents an inactivation of the carrier occurring during its solubilization by Triton. The effect of increasing concentrations of Triton in the solubilization buffer was therefore investigated by measuring the reconstituted citrate exchange activity in both SMP extracts and HTP eluates. In both the cases, the total and the specific activities increase on increasing the concentration of Triton up to 3%, and decrease at higher detergent concentrations although more protein is solubilized. The citrate exchange activity reconstituted from the HTP eluate was characterized by studying the tissue and the substrate specificity.

Defective cell-mediated immunity (CMI) is well documented in patients with chronic renal failure (CRF) due to many factors (1). The aim of our study was to examine the effects of CRF on serum branch-chain amino and keto acids (BCAA-BCKA), visceral proteins and CMI.

Alport's syndrome is a "hereditary nephritis" associated with structural defects of basement membranes in kidneys, ears and eyes, with variable clinical expression. As the acoustic abnormalities are often subclinical, we studied the brainstem auditory evoked responses (ABR) and tonal audiometry in 12 patients (7 males, 5 females, mean age 32.50 +/- 16.70 years) with histologically documented renal lesions consistent with Alport's syndrome. ABR were used to document the altered acoustic-nerve conduction and transmission typical of the early stage of Alport's syndrome. In 11 patients (seven males, four females), we found bilateral delayed latency (I dx: 2.50 +/- 0.80 msec; III dx: 4.24 +/- 0.68 msec; V dx: 7.02 +/- 0.94 msec) and altered waveform I, III, V by ABR. By audiometry eight patients (six males, two females) showed a loss of medium-high tones, and this group included the patients with a negative ABR study. Therefore, the ABR is abnormal in Alport's syndrome; it may be positive in patients with normal tonal audiometry, usually all cochlear functions are grossly intact; the acoustic-nerve lesions in Alport's syndrome may precede the cochlear involvement and clinical hearing loss; the electrophysiological analysis does not identify the particular nervous structures involved in the acoustic pathways.

Some neurophysiological techniques have been employed in clinical nephrology to record abnormalities of nervous conduction in central and peripheral pathways. The electrical monitoring on the peripheral and central nervous systems has allowed the detection of uremic neural injury, the diagnosis of specific electrophysiological abnormalities, the evaluation of various treatments employed and the identification of those abnormalities that uremia can induce. A group of 156 subjects subdivided into four groups were examined: 100 healthy subjects (64 M, 36 F); 56 patients (21 glomerulonephritis, 14 pyelonephritis, 5 nephrolithiasis, 5 polycystic kidney, 4 nephroangiosclerosis, 7 undetermined) with chronic renal failure treated with a conventional low nitrogen diet (CLND, 0.6 g/kg b.w./d. of proteins), 8 of whom passed from CLND to a very low nitrogen diet supplemented with alpha-keto-analogues; a group of 22 of these 56 underwent a regular dialysis treatment for 12 to 15 hours/weekly for 40.5 +/- 10.2 months. Three patients of the CLND group and 13 patients underwent renal transplantation after a variable period of RDT. In the uremic patients we found different populations of motor unit potentials; a decreased MNCV was found in 35% of the CLND patients, RDT patients had slowed MNCV in 42%. The SNCV was compromised more frequently than the MNCV. An increased duration of evoked potentials was sometimes observed in CLND and RDT patients inducing us to consider this a hallmark of uremic syndrome. The alpha-keto-analogues and HD/HP treated patients showed an improvement in several features.(ABSTRACT TRUNCATED AT 250 WORDS)

The infrared spectrum of a mineral is a characteristic feature, which permits the identification of mineral species. The absorption bands arise from vibrations of the atoms or ions in the structure, and the frequencies of vibrations are dependent on the mass of the atoms, the restraining forces of the bonds, and the geometry of the structure. As a result, the spectrum of a mineral is sensitive to isomorphous replacements in its structure, as these affect both bond strengths and atom masses. The symmetry and regularity of a structure play an important part in determining the intensity and frequency of its vibrations, so that the infrared spectrum is often a sensitive indicator of the degree of order of a crystalline mineral. Amorphous structures absorb infrared radiation as strongly as crystalline structures, although their absorption bands are broader and show fewer distinctive features. Nevertheless, infrared spectroscopy is one of the few techniques which can yield information on the structure and composition of amorphous phases.

Alport's syndrome is a "hereditary nephritis" associated with structural defects of basement membranes in kidneys, ears and eyes, with variable clinical expression. As the acoustic abnormalities are often subclinical, we studied the brainstem auditory evoked responses (ABR) and tonal audiometry in 12 patients (7 males, 5 females, mean age 32.50 +/- 16.70 years) with histologically documented renal lesions consistent with Alport's syndrome. ABR were used to document the altered acoustic-nerve conduction and transmission typical of the early stage of Alport's syndrome. In 11 patients (seven males, four females), we found bilateral delayed latency (I dx: 2.50 +/- 0.80 msec; III dx: 4.24 +/- 0.68 msec; V dx: 7.02 +/- 0.94 msec) and altered waveform I, III, V by ABR. By audiometry eight patients (six males, two females) showed a loss of medium-high tones, and this group included the patients with a negative ABR study. Therefore, the ABR is abnormal in Alport's syndrome; it may be positive in patients with normal tonal audiometry, usually all cochlear functions are grossly intact; the acoustic-nerve lesions in Alport's syndrome may precede the cochlear involvement and clinical hearing loss; the electrophysiological analysis does not identify the particular nervous structures involved in the acoustic pathways.

L-CSA and L-Aspartate inhibit each other's transport in the mitochondria in a competitive manner. The D-isomers have very little effect. It is proposed that the two amino acids are transported by a common translocator, presumable the glutamate-aspartate carrier.