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Biomedical subjects

D Durand

Publications and source records attributed to D Durand.

At least 91 records · Page 5Linked to original sources
PubMed1999

Effects of dietary coconut oil on fatty acid oxidation capacity of the liver, the heart and skeletal muscles in the preruminant calf.

The oxidative capacity of the liver, the heart and skeletal muscles for fatty acids were investigated in preruminant calves fed for 19 d on a milk-replacer containing either coconut oil (CO, rich in 12:0) or tallow (rich in 16:0 and 18:1). Weights of the total body and tissues did not differ significantly between the two groups of animals but plasma glucose and insulin concentrations were lower in the CO group. Feeding on the CO diet induced an 18-fold increase in the hepatic concentration of triacylglycerols. Rates of total and peroxisomal oxidation of [1-14C]laurate, [1-14C]palmitate and [1-14C]oleate were measured in fresh tissue homogenates. Higher rates of total oxidation in liver homogenate and of peroxisomal oxidation in liver, heart and rectus abdominis muscle homogenates were observed with laurate used as substrate. Furthermore, the relative contribution of peroxisomes to total oxidation was 1.9-fold higher in the liver and in the heart with laurate than with oleate or palmitate. Finally, the peroxisomal oxidation rate of oleate was 1.5-fold higher in the hearts of calves fed on the CO diet. Whatever the tissue, citrate synthase (CS, EC 4.1.3.7) and cytochrome c oxidase (COX, EC 1.9.3.1) activities were similar between the two groups of calves but the COX: CS activity ratio was lower in the liver of the CO group. In conclusion, laurate is better catabolized by peroxisomes than long-chain fatty acids, especially in the liver. Elongation of lauric acid after partial oxidation might explain the hepatic triacylglycerol accumulation in calves fed on the CO diet.

Analysis of Variance↗
PubMed1998

Fatty acid metabolism and very low density lipoprotein secretion in liver slices from rats and preruminant calves.

The liver of bovine animals possesses a low ability to secrete triglycerides (TG) as part of the very low density lipoproteins (VLDL) compared with rat liver. We compared hepatic fatty acid (FA) metabolism between rat and calf in order to determine the limiting steps of TG-VLDL secretion in bovine animals. Liver slices from young Sprague-Dawley rats and preruminant Holstein x Friesian calves were incubated for 7 h with increasing concentrations (0.1, 0.2, 0.4, and 0.8 mM) of [14C]oleate. The oxidation of oleate to CO2 and acid-soluble products was 2- to 3-fold higher in rat than in calf liver slices. Since oleate uptake was 2-fold higher in rat than in calf, the oxidation rate represented 20-29% of oleate uptake in both animal species. Oleate was essentially incorporated into the neutral lipids (75-87% of total lipids) that were stored mainly in the cytosol in both animal species (81-90% of neutral lipids). The accumulation of neutral lipids in the cytosol was 3.4-fold higher while VLDL secretion was 6- to 18-fold more efficient in rat than in calf liver slices. Our results indicate that the slow rate of VLDL secretion by bovine liver is probably due to the limited availability of TG for VLDL packaging rather than to the preferential oxidation of FA.

Animals↗
PubMed1998

Increased expression of liver PKC alpha in hypoinsulinemic diabetic rats: a post-translational effect.

Ca2+-dependent protein kinase C (cPKC) activity and expression have been studied in livers from hypoinsulinemic streptozotocin (STZ)-induced diabetic and untreated control rats. In diabetic rats, cPKC activity was slightly decreased in liver total particulate and nuclear fractions but was unchanged in mitochondrial-lysosomal, microsomal and cytosolic fractions. On Western immunoblot analysis, PKC alpha was identified as two distinct proteins of 90 and 81 kDa. In diabetic rats, the abundance of the 90 kDa protein was increased in most subcellular fractions with a maximum in the cytosolic and microsomal fractions (180%) but that of the 81 kDa protein was unchanged. PKC beta2 was detected as a single 81 kDa protein in cytosolic and microsomal fractions with unchanged levels in diabetic rats. Liver PKC alpha mRNA levels as measured by reverse transcription and competitive PCR amplification were similar in diabetic and control rats. The increased expression of PKC alpha protein in diabetic rats was reversed by insulin but not by phlorizin, suggesting that it did not result from hyperglycemia. We conclude that STZ-induced diabetes induces the expression of a biologically inactive form of PKC alpha which differs from active PKC alpha by an undefined post-translational modification, possibly an increase in phosphorylation state.

Animals↗
PubMed1998

An uncommon cause of oral ulcers.

A 25-year-old Hispanic woman presented with painful oral ulcers, a sore throat, and dysphagia of two weeks' duration. She was treated empirically with acyclovir for presumed herpes simplex stomatitis and esophagitis and sent home. A week later, she returned with complaints of worsening sore throat, fever (as high as 38.9 degrees C), and cough producing yellow-green sputum. She had not had chills, shortness of breath, burning on urination, or a change in bowel habits.

Adult↗
PubMed1998

Impact of hepatitis C virus duration and hepatitis C virus genotypes on renal transplant patients: correlation with clinicopathological features.

BACKGROUND: The aim of this study was to evaluate the long-term impact of chronic hepatitis C virus (HCV) infection on the liver in renal transplant patients. METHODS: We studied 78 patients for whom at least one posttransplant liver biopsy (LB) was available and for whom the duration of HCV infection was precisely defined. The LB were graded according to a histological activity index, i.e., the Knodell score, divided into the activity score and the fibrosis score. They were also classified as either normal or showing evidence of chronic persistent hepatitis, chronic active hepatitis (CAH), or cirrhosis. RESULTS: The study comprised 7 HCV-positive/hepatitis B surface antigen-positive patients (group 1); 4 HCV-positive/RNA-negative patients (group 2); and 67 HCV-positive/RNA-positive patients (group 3). The three groups were comparable according to demographic data and baseline immunosuppression. The median time from transplantation to LB was 38 months (range, 10-306 months). At that time, alanine aminotransferase (ALT) levels had increased in 71.4%, 0%, and 42% of patients from groups 1, 2, and 3, respectively (P=0.07). The total Knodell score showed significantly more severe lesions in group 1 patients (6.2+/-3.2) than in group 2 (1+/-1.2) or in group 3 (4.6+/-2.4) patients (P=0.007). The Knodell score also showed that the fibrosis score was significantly higher in group 1 (2.3+/-1.6) than in group 2 (0) or in group 3 (0.9+/-1.1) patients (P=0.007). Overall, there were 28 cases of CAH (36%) and 4 cases of cirrhosis (5%). We did not observe any correlation between liver histology and characteristics of HCV infection or the type of chronic immunosuppression (double-drug versus triple-drug therapy). However, liver histology (total Knodell score) and the activity score were significantly correlated with ALT levels. Multivariate analysis did identify (i) four independent variables that could explain the degree of liver fibrosis-the sex of the patient, the number of blood units received before transplantation, increased ALT levels at the time of LB, and the occurrence of at least one acute rejection episode (thus the receipt of methylprednisolone pulses); and (ii) two independent variables associated with the occurrence of CAH-the number of blood units before transplantation and increased ALT levels at the time of LB. CONCLUSION: This study showed that renal transplant patients infected by HCV for more than 10 years, with a mean posttransplant follow-up of more than 5 years, showed more severe liver lesions when coinfected by hepatitis B virus. Overall, we observed only four cases of cirrhosis (5%) and evidence of histological CAH lesions in 36% of the patients.

Adult↗
PubMed1998

Repulsive interparticle interactions in a denatured protein solution revealed by small angle neutron scattering.

In order to investigate the effect of concentration in biological processes such as protein folding, small angle neutron scattering measurements were used to determine the second virial coefficient of solutions of both native and strongly denatured phosphoglycerate kinase and the radius of gyration of the protein at zero concentration. The value of the second virial coefficient is a good probe of the non-ideality of a solution. The present results show that the unfolding of the protein leads to a drastic change in the repulsive intermolecular interactions. We conclude that these interactions are due mainly to the behaviour of the denatured polypeptide chain as an excluded volume polymer.

Fungal Proteins↗
PubMed1998

A confused man with rapid respiration.

A 71-year-old man presented with incoherent, slurred speech, auditory hallucinations, and tachypnea. According to the neighbor who called for emergency medical service, the man had appeared to be in good health the day before. On admission, his blood pressure was normal.

Acidosis↗
PubMed1998

A woman with sudden paralysis.

A 37-year-old Hispanic woman complained of having awakened with a tingling sensation, followed by sudden weakness, in both legs. A month earlier, she had experienced heart palpitations but had not had chest pain or dyspnea. She had lost 10 lb in the last two months despite an increased appetite and no polyuria, polydipsia, vomiting, or diarrhea.

Adult↗
PubMed1998

Excluded volume in the configurational distribution of a strongly-denatured protein.

The configurational distribution of phosphoglycerate kinase (PGK) strongly-denatured in 4 M guanidine hydrochloride solution is investigated using small-angle neutron scattering (SANS) and Monte Carlo computer simulation. It is shown that the experimental scattering profile can be represented by a random flexible chain of spheres of excess scattering density with excluded volume interactions, the best agreement being achieved when partial sphere intersection is allowed. The radius of gyration of the chain increases by a factor of 4 on denaturation, whereas the average length of segments approximately 5 residues long increases by only approximately 10%, consistent with a picture in which the large expansion on denaturation originates primarily from increased long-range flexibility of the polypeptide chain. The results provide a description of the chain statistics from which the construction of starting points for simulation studies of folding of the protein can be envisaged.

Computer Simulation↗
PubMed1998

Effects of 24R,25-dihydroxyvitamin D3 on alkaline phosphatase activity in pig renal epithelial LLC-PK1 cells in culture.

1. The effects of 24R,25-dihydroxyvitamin D3 [24,25(OH)2D3] on alkaline phosphatase activity (ALP) were evaluated in pig kidney LLC-PK1 cells in culture. 2. The vitamin D3 metabolite increased ALP activity in these cells, whereas no effect of the hormone was observed on gamma-glutamyltranspeptidase and acid phosphatase activities. 3. ALP activity was stimulated after 3- to 12-hr incubation in the presence of 10(-9) mol/l 24,25(OH)2D3 with a maximum after 6 hr. 4. The hormonal induction of ALP activity was prevented by pretreatment of cells by actinomycin D. 5. It is proposed that 24,25(OH)2D3 could increase ALP activity by de novo protein synthesis.

24,25-Dihydroxyvitamin D 3↗
PubMed1998

Serological markers of autoimmunity in renal transplant patients with chronic hepatitis C.

The aims of this prospective study were to assess the frequency of serological markers of autoimmunity and cryoglobulins in renal transplant (RT) patients presenting with chronic hepatitis C, and to correlate them with serum alanine aminotransferase (ALT) levels, hepatitis C virus (HCV) genotypes and viremia, and HLA-DR phenotypes. Three groups of patients were studied: group I comprised 74 HCV + ve RT patients; group II, 33 HCV-ve RT patients, and group III, 13 HCV-ve/hepatitis B virus (HBV)-positive RT patients. The three groups did not differ significantly according to their mean age, sex ratio and baseline immunosuppression. Serum specimens of these patients were tested for complement (hemolytic activity (CH50), C3, C4 and properdin factor B (PFB) components, rheumatoid factor (RF), immunoglobulin patterns, circulating immune complexes, and autoantibodies including antinuclear (ANA), anti-smooth muscle (ASMA), antimitochondrial, antithyroid microsomal (ATM), antithyroglobulin (ATG) and anti-LKM1 autoantibodies. We also looked for the presence of cryoglobulins in groups I and III. Cryoglobulinemia of type II was present in 2 patients of group I (2.7%) which was associated in 1 case with de novo membranoproliferative glomerulonephritis but was not found in any of the patients of group III. RF (> 40U/ml) were more frequently observed in groups I (55.4%) and III (46%) than in group II (20.6%), although the difference was not statistically significant (p = 0.06). Oligoclonal or monoclonal serum immunoglobulin patterns were present in 16.2% of the patients in group I, 15.4% in group III and only 3.3% in group II (p = 0.07). There was no significant difference between the prevalence of at least one autoantibody in the three groups (ranging from 38.5 to 50%), and neither was the frequency of ANA (23-36.6%), even at a high titer i.e. above 1:320, or ASMA (13.5-23%) significantly different. Conversely, tissue-specific autoantibodies, i.e. ATM, ATG and anti-LKM1, were only observed in HCV+ve patients. CH50, C3, C4 and PFB levels were significantly lower in group I than in group II, although values below the normal ranges were observed only for CH50 and C3 and were mostly found in the HCV+ve RT patients. Circulating immune complexes detected by nephelometry were at similar levels in the three groups, within the normal ranges. The occurrence of at least one autoantibody and/or the presence of RF > 40 U/ml did not correlate with either serum ALT levels or a given HLA-DR phenotype in any of the three groups, nor did they correlate with HCV genotype or HCV viremia in group I. In conclusion, this study shows that contrary to HCV+ve immunocompetent patients, HCV+ve RT patients rarely present with cryoglobulinemia and have the same frequency of non-organ-specific autoantibodies as HCV-ve RT patients. Conversely, antithyroid autoantibodies are only observed in the former group. Finally, serological markers of autoimmunity are not related to serum ALT levels, HLA-DR phenotype, HCV viremia or HCV genotype in HCV+ve RT patients.

Adult↗
PubMed1998

Developmental changes in apolipoprotein B gene expression in the liver of fetal calves.

Changes in apolipoprotein (apo B) gene expression in the liver were determined in fetal calves from 90 to 260 days of intrauterine life. Results were compared with those obtained from the livers of 1-month-old calves and adult cows. By Western blot analysis using a rabbit antiserum to bovine apo B, apo B100 was detected from 90 days of intrauterine life. Apo B100 was shown to be the only form of apo B detected in the liver of fetal calves whatever the gestational age indicating the lack of editing process during the prenatal period. Hepatic apo B contents were stable during intrauterine life and comparable to those of calves and lower than those of cows. Hepatic contents of apo B mRNA increased with the gestational age similarly to total RNA. Values of apo B mRNA at 260 days of intrauterine life were comparable to those in the liver of 1-month-old calves and adult cows. These results suggested that hepatic synthesis of calf apo B during fetal development is specifically regulated at a posttranscriptional level, either by a decrease in the rate of translation and/or by an increase in the rate of intracellular apo B degradation.

Aging↗