Biomedical subjects
Publications and source records attributed to C Godart.
Duplications of the alimentary tract are rare congenital anomalies and vermiform appendix duplication is exceptional. The aim of this study was to report a case of cystic appendiceal duplication in a 4 years old child, unusual in its anatomic type, its clinical presentation and its way of management.
Hb Mont Saint-Aignan [beta128(H6)Ala-->Pro] is a mildly unstable variant, associated with hemolytic anemia, marked microcytosis and increased alpha/beta biosynthetic ratio (1.55 versus 1.1 +/- 0.1 in the control). The abnormal chain was isolated by selective precipitation with isopropanol and the structural modification determined by protein chemistry methods (reversed phase high performance liquid chromatography and mass spectrometry). Possible mechanisms underlying the beta(+)-thalassemia-like expression of this variant are discussed.
Laboratory methods allowing the detection and characterization of hemoglobin variants are reviewed. Protein chemistry techniques such as isoelectrofocusing, electrophoreses under various experimental conditions, cation exchange and reversed phase high performance liquid chromatography, are the most frequently used for the detection of variants. When associated with a few additional data they may lead to a presumptive diagnosis. DNA studies are also developed in many laboratories. Final identification of a variant may be achieved either by molecular biology techniques or by protein sequence analysis in which mass spectrometry now occupies a key position.
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BACKGROUND: Ischemia-reperfusion injury (IRI) is often responsible for graft rejection and leads to delayed graft function of cadaveric kidneys. We have shown that adding polyethylene glycol (PEG 20M) to the preservation solutions helps protect isolated perfused pig kidneys against cold ischemia and reperfusion injury. METHODS: We compared the effects of adding PEG to a simplified high-K+ perfusion solution of cold-stored kidneys to Euro-Collins or University of Wisconsin solutions on the function of reperfused autotransplanted pig kidneys. The left kidney was cold-flushed with the preservation solutions and stored for 48 hr at 4 degrees C before reimplantation. Creatinine clearance and fractional excretion of sodium were analyzed 2 days before surgery and over 7 days after transplantation. Histological sections were obtained 40 min after reperfusion and on day 7 after surgery. RESULTS: Adding PEG to the perfusate significantly reduced IRI from autotransplanted pig kidneys. Creatinine clearance was significantly higher and fractional excretion of sodium was significantly lower in pigs transplanted with kidneys cold-flushed with PEG-supplemented perfusate than in those flushed with Euro-Collins or University of Wisconsin solutions. PEG supplementation also better preserved the integrity of kidney cells and markedly reduced interstitial cell infiltrates. CONCLUSION: PEG protects against IRI and reduces early cellular inflammation. PEG may impair the recruitment and migration of leukocytes into retransplanted pig kidneys. Cold preservation of donor organs with PEG-supplemented solutions may therefore help limit IRI in human renal transplantation.
BACKGROUND: Delayed graft function (DGF) has remained an important complication after renal transplantation. The exact causes of DGF remain to be clarified, particularly the impact of retrieval conditions and preservation factors. In the present investigation, (1)HNMR spectroscopy of urine was assessed in order to detect the influence of retrieval condition on renal medulla damage. METHODS: The isolated perfused pig kidney (IPK) was used to assess initial renal function from multiorgan donors (MOD) or single organ donors (SOD) after in situ cold flush and 24-h cold storage (CS) preservation with two standard preservation solutions: Euro-Collins (EC) and University of Wisconsin (UW) solutions. Kidneys flushed with cold heparinized saline and immediately perfused were used as the control group. Kidneys were perfused for 90 min at 37.5 degrees C for functional evaluation. During reperfusion, renal perfusion flow rate (PF) was measured. Glomerular filtration rate (GFR), tubular reabsorption of Na(+), and lactate dehydrogenase (LDH) and N-acetyl-beta-d-glucosaminidase (NAG) excretions were determined. Ischemia-reperfusion impairment was also determined by histological techniques and (1)HNMR spectroscopy. RESULTS: PF, GFR, and tubular reabsorption of Na(+) were significantly decreased in experimental groups when compared to the control group but there was no significant difference between experimental SOD groups. GFR was significantly greater in UW-MOD than in EC-MOD and tubular reabsorption of Na(+) was significantly greater in UW-MOD than in EC-MOD after 45 min of reperfusion. The release of LDH in the effluent and the urinary excretion of NAG were not significantly different after 24-h CS in the various experimental groups. The most relevant resonances determined by (1)HNMR spectroscopy were citrate, trimethylamine-N-oxide, lactate, acetate, and amino acids. Excretion of these markers was significantly different when compared to biochemical markers. A resonance (P) detected particularly in EC-MOD after 24-h CS was identified and well correlated to renal dysfunction. Histological study showed that ultrastructural damage and mitochondrial injury were more pronounced in the EC-MOD group. CONCLUSION: These results show that retrieval condition influences renal medullary damage. NMR spectroscopy, which is a noninvasive and nondestructive technique, is more efficient in assessing renal damage than conventional histology and biochemical analysis.
In the present investigation, the influence of retrieval condition on medullary damage in kidneys was assessed. The isolated perfused pig kidney was used to assess initial renal function from multiorgan donors or single organ donors after cold flush and 24 h cold storage preservation with two preservation solutions: Euro-Collins and University of Wisconsin solutions. Kidneys flushed with cold heparinized saline and immediately perfused were used as a control group. Kidneys were perfused for 90 min at 37.5 degrees C and renal perfusion flow rate, glomerular filtration rate, tubular reabsorption of Na+ and lactate dehydrogenase and N-acetyl-beta-D-glucosaminidase excretion were determined. Ischaemia reperfusion impairment was also determined by 1H NMR (proton nuclear magnetic resonance) spectroscopy. Renal function was significantly decreased in experimental groups when compared to the control group, but there was no significant difference between experimental groups after 24 h cold storage. The release of lactate dehydrogenase in the effluent and the urinary excretion of N-acetyl-beta-D-glucosaminidase were not significantly different after 24 h cold storage. The most relevant resonances determined by 1H NMR spectroscopy were citrate, trimethylamine-N-oxide, lactate, acetate and amino acids. Excretion of these markers was significantly different when compared to biochemical markers. A resonance P (Peak) detected particularly in Euro-Collins solution multiorgan donors after 24 h cold storage was identified and well correlated to renal dysfunction. N-acetyl-beta-D-glucosaminidase spectroscopy, which is a non-invasive and non-destructive technique, is more efficient to assess renal damage than conventional histology and biochemical analysis.
In organ transplantation, the determination of reliable parameters to assess ischaemic damage is essential to predict renal injury after preservation. The aim of this study was to assess renal medullary injury by 1H NMR (proton nuclear magnetic resonance) spectroscopy after preservation and reperfusion. Three experimental groups of pigs were examined during a 2-week period: control group (n = 4), Euro-Collins group (EC) (cold flushed and 48 h cold storage of kidney in EC and autotransplantation, n = 7), and University of Wisconsin (UW) group (cold flushed and 48 h cold storage of kidney in UW and autotransplantation, n = 7). Creatinine and urea were improved in the two cold stored groups. The most relevant resonances determined by 1H NMR spectroscopy after transplantation were those arising from citrate and acetate in urine and trimethylamine-N-oxide (TMAO) in urine and plasma. We demonstrate that graft dysfunction is associated with damage to the renal medulla as determined by TMAO release in urine and plasma. Conversely, citrate excretion can discriminate kidneys with favourable outcome. This study outlines the specific and beneficial impact of UW solution on renal preservation and suggests that 1H NMR spectroscopy is efficient both to detect ischaemic damage of preserved kidneys and to discriminate the preservation quality between different preservation solutions.
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We here report two new, clinically silent, hemoglobin variants in which the structural modification disturbs the oxygen-linked chloride binding. Hb Antananarivo [alpha1(NA1)Val-->Gly] was found during a systematic hematological study in a 24-year-old woman, who originates from Madagascar. Hb Barbizon [beta144 (HC1)Lys-Met] was found in several members of a French family. The oxygen binding properties of Hb Barbizon were similar to those of Hb Antananarivo showing, in vitro, a decreased chloride effect as compared to Hb A. In Hb Barbizon, the replacement of lysine beta144 by a methionine residue decreased from 4 to 2 the excess positive charges in the central cavity, thus leading to a reduction of about half of the chloride effect. For Hb Antananarivo, the mechanism is unclear since there is no difference in the number of positive charges in the central cavity but alterations are likely at the alpha1alpha2 interface.
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Three hemoglobin variants (Hb Nancy, Osler and Fort Gordon), carrying the same Tyr-->Asp substitution at position beta 145 (HC2), have been independently described in 1975 in patients with marked polycythemia. The first one was found in a French caucasian family from Lorraine, and the two others in African Americans. Two unrelated individuals with Hb Osler have been recently reinvestigated at the DNA level and surprisingly, in their beta gene, codon 145 was found to be AAT which encodes for asparagine and not for aspartic acid, the aspartate at the protein level resulting, thus, from a very efficient posttranslational event. We reinvestigated a patient from the family of Hb Nancy and found that codon 145 was GAT, encoding for aspartate. This demonstrates that Hb Nancy is genetically distinct from Hb Osler despite an almost identical phenotype.
Single point mutation, which accounts for 92% of the 700 known variants, is the most frequent genetic defect responsible for abnormal haemoglobins. Small deletions (or insertions) involving from one to five residues are also observed, but in only approximately 5% of cases. The remaining variants produce fusion or extended haemoglobins. A deletion of eight residues, which included the distal histidine and its neighbours (alpha50-57, alpha51-58 or alpha52-59), was found in Hb J-Biskra. This new alpha-chain variant was mildly unstable in vitro only and there was no haematological or biochemical evidence of haemolysis in the affected family members. 24 nucleotides were missing in a region of the alpha1 gene showing an identical sequence of eight nucleotides at both ends. Several starting points could therefore lead to the same nucleotide and aminoacid remaining sequence. This deletion is the largest up to now reported in a haemoglobin molecule which is expressed at an almost normal level in the red blood cell. Comparison of the DNA sequences near to the deleted (or inserted) regions in the various haemoglobins carrying this type of abnormality almost always revealed the presence of a sequence that was hypothesized to slow down progression of the replication fork, and of repeats that may lead to possible secondary structures favouring slipped mispairing.
A battery of relatively simple tests allows the presumptive identification of hemoglobin (Hb) variants, making unnecessary structural analysis by protein chemistry methods or DNA sequencing. The primary step in this strategy involves the use of a matrix of electrophoretic mobilities obtained under various experimental conditions. This leads to an unambiguous result in approximately 90% of the cases. Additional tests are required to characterize with more confidence the remaining 10%. We describe here the use of cation-exchange HPLC on the Bio-Rad Variant automated analyzer with the "beta Thalassemia Short" program. By comparing the elution time of 125 human Hb mutants, we found that some variants with almost identical pI values or produced by the same type of amino acid substitution displayed different elution times. We present several examples in which use of the HPLC profile helped establish the diagnosis.
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