Metabolism of dairy cows as affected by prepartum dietary carbohydrate source and supplementation with chromium throughout the periparturient period.

Holstein cows (n = 72) entering second or later lactation were used to determine whether metabolic indices and hepatic capacities for oxidation and gluconeogenesis from propionate are affected by source of carbohydrate in the prepartum diet and chromium-l-methionine (Cr-Met) supplementation throughout the periparturient period. Cows were fed prepartum diets as total mixed rations with the concentrate portion based either on starch-based cereals [high nonfiber carbohydrate (NFC); 1.59 Mcal/kg of net energy for lactation (NE(L)), 14.4% crude protein (CP), 40.3% NFC] or nonforage fiber sources (low NFC; 1.54 Mcal/kg of NE(L), 14.5% CP, 33.6% NFC) from 21 d before expected parturition until parturition. After parturition all cows were fed a common lactation total mixed ration (1.74 Mcal/kg of NE(L), 16.5% CP, 40.0% NFC). The Cr-Met was supplemented once daily via gelatin capsule at dosages of 0, 0.03, or 0.06 mg of Cr/kg of BW(0.75). Thus, treatments were in a 2 (carbohydrate source) x 3 (Cr-Met) factorial arrangement. There was no effect of prepartum carbohydrate source on pre- and postpartum plasma concentrations of glucose, nonesterified fatty acids (NEFA), beta-hydroxybutyrate (BHBA), insulin, glucagon, or insulin to glucagon ratio. However, cows fed the low NFC diet during the prepartum period tended to have greater plasma NEFA and lower BHBA concentrations postpartum. Liver glycogen concentrations tended to be greater on d 1 postpartum for cows fed low NFC prepartum. Supplementing 0.03 mg/kg of BW(0.75) of Cr as Cr-Met increased prepartum plasma glucose and glucagon concentrations and tended to decrease prepartum plasma NEFA concentrations compared with either 0 or 0.06 mg of Cr/kg of BW(0.75). Postpartum plasma glucose concentrations decreased linearly and glucagon concentrations were increased quadratically by administering increasing amounts of Cr-Met. Supplementing Cr-Met did not affect prepartum plasma concentrations of insulin or BHBA, postpartum NEFA or BHBA, or liver composition. There was an interaction of prepartum carbohydrate source and Cr-Met supplementation such that in vitro hepatic conversion of [1-(14)C]propionate to both CO(2) and glucose was similar or increased when Cr-Met was supplemented to cows fed the low NFC diet but decreased when Cr-Met was supplemented to cows fed the high NFC diet. Insulin addition in vitro did not affect hepatic metabolism of propionate on d 1 postpartum. Overall, both the NFC content of the prepartum diet and Cr-Met had only modest effects on metabolic indices in this experiment.

Collagen VII expression in glomerular sclerosis.

Glomerular sclerosis is the final stage of a variety of kidney diseases and matrix molecules not normally expressed in the extracellular matrix are synthesized and accumulate during the sclerotic process. Collagen type VII is the major component of the anchoring fibrils at the dermal-epidermal junction, but it is usually not present in normal glomeruli. The aim of this study was to investigate whether this type of fibrillary collagen, different from types I and III, is expressed in chronically diseased glomerular extracellular matrix. The presence and distribution of collagen VII have been examined in 50 renal biopsies by indirect immunofluorescence staining, standard electron microscopy, and immuno-electron microscopy. In selected cases, collagen VII mRNA expression was also measured by RT-PCR on isolated glomeruli. Cases included focal segmental glomerulosclerosis, minimal change disease, membranous glomerulonephritis, IgA nephropathy, SLE nephritis, diabetic glomerulosclerosis, ischaemic renal disease, extracapillary glomerulonephritis, and end-stage renal disease. Collagen VII protein and mRNA expression was absent or present in trace amounts in normal kidneys or in disorders with only a mild increase of mesangial matrix, without scarring of the tuft. Maximal expression was evident in the presence of adhesions between the glomerular tuft and Bowman's capsule or fibrous crescents. The results showed that collagen VII is actively synthesized and laid down in areas of glomerular and/or tubular scarring, irrespective of the underlying disease, confirming the de novo expression of fibrillary collagens in diseased renal extracellular matrix. The appearance of an anchoring collagen may be a response to support mechanical stress and it takes part in the process of cell proliferation and tissue repair.

A homozygous nonsense mutation in type XVII collagen gene (COL17A1) uncovers an alternatively spliced mRNA accounting for an unusually mild form of non-Herlitz junctional epidermolysis bullosa.

In this study we describe six Italian patients presenting an unusually mild variant of non-Herlitz junctional epidermolysis bullosa associated with a reduced expression of type XVII collagen. All patients are homozygous for a novel nonsense mutation (R795X) within exon 33 of COL17A1 and show a common haplotype, attesting propagation of an ancestral allele within the Italian population. Analysis of patients' COL17A1 transcripts showed the presence of two mRNA species: a normal-sized mRNA carrying mutation R795X that undergoes rapid decay, and a transcript generated by in-frame skipping of exon 33. Patients keratinocytes were shown to synthesize minute amounts of type XVII collagen, which appeared correctly localized along the cutaneous basement membrane. We therefore suggest that the exon 33-deleted COL17A1 splice variant encodes for type XVII collagen molecules that maintain a functional role and account for the mild phenotype of our patients.

A homozygous mutation in the integrin alpha6 gene in junctional epidermolysis bullosa with pyloric atresia.

The alpha6 integrin subunit participates in the formation of both alpha6beta1 and alpha6beta4 laminin receptors, which have been reported to play an important role in cell adhesion and migration and in morphogenesis. In squamous epithelia, the alpha6beta4 heterodimer is the crucial component for the assembly and stability of hemidesmosomes. These anchoring structures are ultrastructurally abnormal in patients affected with junctional epidermolysis bullosa with pyloric atresia (PA-JEB), a recessively inherited blistering disease of skin and mucosae characterized by an altered immunoreactivity with antibodies specific to integrin alpha6beta4. In this report, we describe the first mutation in the alpha6 integrin gene in a PA-JEB patient presenting with generalized skin blistering, aplasia cutis, and defective expression of integrin alpha6beta4. The mutation (791delC) is a homozygous deletion of a single base (C) leading to a frameshift and a premature termination codon that results in a complete absence of alpha6 polypeptide. We also describe the DNA-based prenatal exclusion of the disease in this family at risk for recurrence of PA-JEB. Our results demonstrate that, despite the widespread distribution of the alpha6 integrin subunit, lack of expression of the alpha6 integrin chain is compatible with fetal development, and results in a phenotype indistinguishable from that caused by mutations in the beta4 chain, which is expressed in a more limited number of tissues.

["Banding" of the venous side of an arteriovenous fistula for hemodialysis complicated with steal syndrome: a clinical case]. / "Banding" del versante venoso di fistola artero-venosa per emodialisi complicata da sindrome di furto periferico: un caso clinico.

The duration of an arteriovenous fistula has a limit. In fact there are some complications that compromise a good working of them. We have dealed on of these complications, a steal syndrome of an omero-cephalic fistula by a simple operation of "banding" using a ring of Teflon around the arterialized vein getting a good clinical result with a good preservation of the blood flow trans-fistula.

HCV in a group of chronic hemodialysis patients.

Since HCV appears to be the major cause of post-transfusion non-A, non-B hepatitis in Italy, this study determines the presence of anti-HCV in a risk group. Among 26 patients, 9 were anti-HCV in a risk group. Among 26 patients, 9 were anti-HCV positive with the ELISA test and all of them were confirmed with the RIBA test of 2nd generation. Only 1 had a poussés movement of ALT levels. Hemodialyzed patients are reactive for HCV probably for the transfusional therapy.

Progressive inactivation of the expression of an erythroid transcriptional factor in GM- and G-CSF-dependent myeloid cell lines.

The transcriptional binding protein NFE-1 (also called GF-1 and Ery-f1) is thought to play a necessary, but not sufficient, role in the regulation of differentiation-related gene expression in a subset of hematopoietic lineages (erythroid, megakaryocytic, and basophil-mast cell). In order to clarify the mechanism which underlies the lineage-specificity of the NFE-1 expression, as well as the relationship between the expression of this factor and growth factor responsiveness, we have evaluated the capacity of erythropoietin (Epo)-, granulomonocytic (GM)-colony stimulating factor (CSF)-, and granulocyte (G)-CSF-dependent subclones derived from the interleukin 3 (IL-3)-dependent cell line 32D, to express 1) NFE-1 mRNA, 2) NFE-1-related nuclear proteins, and 3) chloramphenicol acetyl transferase (CAT) activity when transfected with a CAT gene under the control of NFE-1 cognate sequences. NFE-1 mRNA was found to be expressed not only in cells with mast cell (IL-3-dependent 32D) and erythroid (Epo-dependent 32D Epo1) phenotypes, but also in cells with predominantly granulocyte/macrophage properties, such as the GM-CSF- (early myelomonocytic) and G-CSF- (myelocytic) dependent subclones of 32D. However, a gradient of expression, correlating with the lineage, the stage of differentiation, and the growth factor responsiveness of the cell lines, was found among the different subclones: Epo greater than or equal to IL-3 greater than GM-CSF greater than G-CSF. Binding experiments demonstrated NFE-1 activity in all cell lines except the G-CSF-dependent line. Function of the NFE-1 protein was assessed by the expression of the CAT gene linked to the SV40 promoter and a mutant (-175 T----C) HPFH gamma-globin promoter. High level CAT expression was seen only in the Epo1 cells although low level expression was also seen in the parent 32D. These results demonstrate that the specificity of the expression of NFE-1 for the erythroid--megakaryocytic--mast cell lineages is obtained by progressive inactivation of its expression in alternative lineages.

Nucleotide deficit and functional platelet alterations in patients on regular dialysis treatment (RDT).

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.