Acute effects of acidosis on protein and amino acid metabolism in perfused rat liver

Acidosis is frequently associated with protein wasting and derangements in amino acid metabolism. As its effect on protein metabolism is significantly modulated by other abnormal metabolic conditions caused by specific illnesses, it is difficult to separate out the effects on protein metabolism solely due to acidosis. The aim of the present study was to evaluate, using a model of isolated perfused rat liver, the direct response of hepatic tissue to acidosis. We have compared hepatic response to perfusion with a solution of pH 7.2 and 7.4 (controls). Parameters of protein and amino acid metabolism were measured using both recirculation and single-pass technique with 4,5-[3H]leucine, [1-14C]leucine and [1-14C]ketoisocaproate (ketoleucine) as tracers and on the basis of difference of amino acid levels in perfusion solution at the beginning and end of perfusion. In liver perfused with a solution of pH 7.2, we observed higher rates of proteolysis, protein synthesis, amino acid utilization and urea production. Furthermore, the liver perfused with a solution of pH 7.2 released a higher amount of proteins to perfusate than the liver perfused with a solution of pH 7.4. Enhanced decarboxylation of ketoisocaproate in liver perfused by a solution of a lower pH indicates increased catabolism of branched-chain amino acids (leucine, valine and isoleucine), decreased reamination of branched-chain keto acids to corresponding essential amino acids and increased ketogenesis from leucine.     

Sleep disturbances and hypocretin deficiency in Niemann-Pick disease type C

DESIGN AND PATIENTS: Subjects with Niemann-Pick disease, type C have been reported to display narcolepsylike symptoms, including cataplexy. In this study, 5 patients with juvenile Niemann-Pick disease were evaluted for sleep abnormalities using nocturnal polysomnography, clinical evaluation, and the Multiple Sleep Latency Test. HLA typing and cerebrospinal fluid hypocretin levels were also evaluated in 4 patients. Niemann-Pick disease diagnosis was confirmed in all cases biochemically and by the presence of foam cells in the bone marrow. RESULTS: Deterioration of intellectual function; the presence of pyramidal, dystonic and cerebellar features; and splenomegaly were observed in all cases. Cataplexy was reported in 1 patient. Nocturnal polysomnography revealed disrupted sleep in all patients. Total sleep time, sleep efficiency, rapid eye movement sleep, and delta sleep amounts were decreased when compared to age-matched controls. Altered sleep patterns included sudden increases in muscle tone during delta sleep, electroencephalographic sigma activity connected with rapid eye movements and muscle atonia, atypical K-complexes and spindle activity, and the presence of alpha-delta sleep. All Niemann-Pick disease cases exhibited fragmentary myoclonus. Shortened mean sleep latencies were observed in 3 patients during the Multiple Sleep Latency Test, but sleep-onset rapid eye movement periods were observed only in the case with cataplexy. This patient was HLA DQB1*0602 positive, while the other subjects were HLA negative. Cerebrospinal fluid hypocretin-1 levels were reduced in 2 patients (1 with cataplexy) while in the 2 other patients, the levels were at the lower range of the normal values. Hypocretin levels in the Niemann-Pick disease group (204.8 +/- 39.3 pg/mL) were significantly reduced when compared to controls (265.8 +/- 48.8 pg/mL). CONCLUSIONS: The findings suggest that lysozomal storage abnormalities in Niemann-Pick disease patients may impact the hypothalamus and, more specifically, hypocretin-containing cells. These changes might be partially responsible for sleep abnormalities and cataplexy in patients with Niemann-Pick disease.     

Abnormal migration of human wild-type alpha-synuclein upon gel electrophoresis

Alpha-synuclein aggregates have been linked to the pathogenesis of Parkinson's disease (PD), with Lewy bodies (LBs) and Lewy neurites (LNs) constituting the pathological hallmarks in the brains of patients with PD and dementia with LBs. LBs are formed by the conversion of soluble monomers of alpha-synuclein into insoluble aggregates. Here we report an abnormal electrophoretic mobility, at a higher molecular weight (MW) than the expected theoretical MW, of both recombinant histidine-tagged human alpha-synuclein, human alpha-synuclein expressed in SH-SY5Y human neuroblastoma cells or Ltk(-) fibroblasts, and rat brain alpha-synuclein, on SDS-PAGE polyacrylamide, but not on Nu-PAGE gradient peptide, gels, suggesting possible alpha-synuclein data misinterpretations associated with gel electrophoresis. These studies raise important considerations about the type of protein gel electrophoresis system suitable to study the alterations of alpha-synuclein associated with neurodegeneration, PD and other synucleinopathies.     

Electrophysiological and proarrhythmic parameters in transmural canine left-ventricular needle biopsies

This study was designed to validate the use of small, transmural, left-ventricular biopsies in the dog for investigations of electrophysiological and proarrhythmic properties of the heart. This technique could facilitate pharmacological in vitro testing in remodelled hearts of both man and animal. Small, transmural, semi-cylindrical, left-ventricular biopsies from dogs with normal sinus rhythm (SR) were characterized electrophysiologically and compared with biopsies from electrically remodelled hearts from dogs with chronic, complete AV-block (CAVB). In at least five biopsy segments recordings were made to determine the action potential duration (APD), the transmural gradient of repolarization, the maximal transmural dispersion (tM_max) and presence of early after-depolarizations (EADs) at different pacing cycle lengths (PCLs) in the absence and presence of a class-III agent, ibutilide (10^–6 M). The biopsies showed stable and normal AP characteristics, a conduction velocity of 0.22±0.05 m/s and normal frequency dependence of the APD. The location of the longest APD varied, thus creating transmural repolarization gradients with differing morphology. Ibutilide prolonged the APD, accentuated repolarization gradients and induced EADs. CAVB biopsies had significantly longer APDs, a larger dispersion of repolarization and showed more EADs in the presence of ibutilide than SR biopsies. We conclude that this biopsy technique provides coherent and valid transmural electrophysiological data in dogs under various conditions.     

Comparison of four different short dialysis techniques

The goal of shortening dialysis treatment time has stimulated the development of new, highly efficient dialytic strategies. In this study the Authors compared four different short dialysis treatments in terms of efficiency, clinical tolerance, technological investment and costs: 1) Rapid bicarbonate dialysis with 1.5 sq.m. cuprophane membrane; 2) High flux biofiltration with 1.2 sq.m. AN69S hollow fiber membrane; 3) Hemodiafiltration with 1.2-1.9. sq.m. polysulphonic hollow fiber hemodiafilters, and 4) High flux hemodiafiltration with two serial hemodiafilters with AN69s membrane (total 2.4 sq.m.). Hydraulic properties and solute clearances at different blood flows (300-500 ml/min) were tested for each technique. Once the optimal operative level was established three patients were treated with each technique for at least six months. Since BUN clearance averaged 310 ml/min, the treatment duration varied from 120 to 180 min/session with KT/V always higher than 1. The average protein catabolic rate was 0.9 g/kg/24h. Clinical tolerance was generally good, slightly better in treatments with a high convective component. Despite the greater efficiency of treatment No. 4, the technological requirements and costs are such that the others are currently more feasible and acceptable in clinical routine. The study demonstrates that reduction of dialysis treatment time is possible in all centres in a selected population with adequate blood access. Treatment No. 1 can even be performed with standard equipment and cuprophan membranes, while bicarbonate in the dialysate is mandatory. The real limit to shortening treatment time seems to be related to the maximal rate of ultrafiltration achievable in the patient during dialysis.     

The coincidence of pure lipoma, leiomyoma, and endometrial cancer. A case report of the uterine tumor triplicity

A different tumor concurrence of the uterine body is usually encountered as a coincidence of leiomyoma and endometrial cancer. Pure lipomatous tumors or fatty change in the leiomyoma or endometrium are rare affections with some diagnostic peculiarities. We present a case of association of the pure uterine lipoma, leiomyoma, and endometrial cancer as a tumor triplicity, which may contribute, to the pathogenesis of mesenchymal tumors in this location.     

Ultrastructural Aspect of Myocarditis: Its Relevance for the Diagnosis

The Dallas consensus was used to reveal active or borderline inflammatory loci by light microscopy (LM). When lympho-cyte-cardiocyte interaction was observed by electron microscopy (EM), the deleterious or dormant pattern of inflammatory process was recognized. The first was determined by lymphocytes that adhered to cardiocytes, next to necrotic cardiocytes or admixed with debris. The second was marked by scattered lymphocytes between preserved cardiocytes and the absence of lymphocytes adhered to cardiocytes and necrotic cardiocytes. The deleterious pattern of the inflammatory process (EM) commonly supplemented the active appearance of inflammatory loci (LM). In contrast, the borderline outlook of the LM completed either the deleterious or dormant pattern of the EM. This discrepancy was related to the restricted resolution of LM, which might hide the actual stage of the disease. The diagnosis of myocarditis was founded on mutual LM and EM observations. The active or borderline appearance of LM of the deleterious pattern (EM) was considered indicative for the active stage of myocarditis. The borderline outlook of the LM of the dormant pattern of the EM was admitted to indicate either the healing phase of the disease with lymphocytes still lagging behind, or a latent phase of the ongoing myocarditis, according to the patient's hemodynamic status.     

Cystic fibrosis: a worldwide analysis of CFTR mutations--correlation with incidence data and application to screening

Although there have been numerous reports from around the world of mutations in the gene of chromosome 7 known as CFTR (cystic fibrosis transmembrane conductance regulator), little attention has been given to integrating these mutant alleles into a global understanding of the population molecular genetics associated with cystic fibrosis (CF). We determined the distribution of CFTR mutations in as many regions throughout the world as possible in an effort designed to: 1) increase our understanding of ancestry-genotype relationships, 2) compare mutational arrays with disease incidence, and 3) gain insight for decisions regarding screening program enhancement through CFTR multi-mutational analyses. Information on all mutations that have been published since the identification and cloning of the CFTR gene's most common allele, DeltaF508 (or F508del), was reviewed and integrated into a centralized database. The data were then sorted and regional CFTR arrays were determined using mutations that appeared in a given region with a frequency of 0.5% or greater. Final analyses were based on 72,431 CF chromosomes, using data compiled from over 100 original papers, and over 80 regions from around the world, including all nations where CF has been studied using analytical molecular genetics. Initial results confirmed wide mutational heterogeneity throughout the world; however, characterization of the most common mutations across most populations was possible. We also examined CF incidence, DeltaF508 frequency, and regional mutational heterogeneity in a subset of populations. Data for these analyses were filtered for reliability and methodological strength before being incorporated into the final analysis. Statistical assessment of these variables revealed that there is a significant positive correlation between DeltaF508 frequency and the CF incidence levels of regional populations. Regional analyses were also performed to search for trends in the distribution of CFTR mutations across migrant and related populations; this led to clarification of ancestry-genotype patterns that can be used to design CFTR multi-mutation panels for CF screening programs. From comprehensive assessment of these data, we offer recommendations that multiple CFTR alleles should eventually be included to increase the sensitivity of newborn screening programs employing two-tier testing with trypsinogen and DNA analysis.     

Interspecies transplacement of mitochondria in yeasts

Protoplasts of a respiration-deficient rho⁰ strain of Saccharomyces cerevisiae were incubated with mitochondria isolated from various respiration-competent yeast species under conditions enabling transplacement of mitochondria. Respiration-competent cybrids were selected by plating the protoplasts on agar media containing a non-fermentable energy source. The resulting cybrids contained nuclear DNA of the acceptor S. cerevisiae and mitochondrial DNA of the donor species, as detected by pulsed-field gel electrophoresis of chromosomes and restriction analysis of mitochondrial DNA, respectively. Successful restoration of respiration in the S. cerevisiae mutant was achieved by transplacement of mitochondria isolated from the following Saccharomyces species: S. bayanus, S. capensis, S. delbrueckii, S. exiguus, S. italicus and S. oviformis. Received: 25 February 1997