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Biomedical subjects

M Adamowicz

Publications and source records attributed to M Adamowicz.

9 recordsLinked to original sources

Genomic organization of the human phosphomannose isomerase (MPI) gene and mutation analysis in patients with congenital disorders of glycosylation type Ib (CDG-Ib).

CDG-Ib is the "gastro-intestinal" type of the congenital disorders of glycosylation (CDG) and a potentially treatable disorder. It has been described in patients presenting with congenital hepatic fibrosis and protein losing enteropathy. The symptoms result from hypoglycosylation of serum- and other glycoproteins. CDG-Ib is caused by a deficiency of mannose-6-phosphate isomerase (synonym: phosphomannose isomerase, EC 5.3.1.8), due to mutations in the MPI gene. We determined the genomic structure of the MPI gene in order to simplify mutation detection. The gene is composed of 8 exons and spans only 5 kb. Eight (7 novel) different mutations were found in seven patients with a confirmed phosphomannose isomerase deficiency, analyzed in the context of this study: six missense mutations, a splice mutation and one insertion. In the last, the mutation resulted in an unstable transcript, and was hardly detectable at the mRNA level. This emphasizes the importance of mutation analysis at the genomic DNA level.

Congenital Disorders of Glycosylation↗

Histological examination of the topography of the atrioventricular nodal artery within the triangle of Koch.

UNLABELLED: The treatment of choice in patients with drug-resistant atrioventricular nodal reentry tachycardia is radiofrequency fast or slow pathway ablation. Ablation of the reentrant circuit in the region of the His bundle, when approached from the anterior-superior region (fast pathway); can result in complete AV block. This is less likely if the posterior-inferior (in the region of coronary sinus ostium) approach is used (slow pathway ablation). The possibility that radiofrequency energy may damage the vascular supply to the AV node must be considered. In order to confirm this hypothesis observation was conducted on the autopsy material of 50 human hearts (20 F, 30 M) from 18 to 81 years of age. Specimens were taken containing the triangle of Koch (the apex- right fibrous trigone, the base- coronary sinus ostium). These histological blocks were sectioned in the frontal plane and stained using Masson's method. Koch's triangle was divided in the sagittal plane into 3 parts: inferior (between the base and the attachment of the tricuspid valve), central (between the base and the apex of the right fibrous trigone) and superior (between this trigone and the tendon of Todaro). It was observed that the AVN artery at the coronary sinus ostium level (the base of the triangle of Koch) was positioned in 68% in the central and in 32% in the inferior part of Koch's triangle. The AVN artery in the central part was removed from the endocardium 1 mm (18%), 2 mm (42%), 3 mm (22%), 4 mm (18%). In the inferior part 1 mm (26%), 2 mm (37%), 3 mm (37%). No statistically significant relationship was observed between those groups. CONCLUSIONS: 1) in 20% of examined hearts the AVN artery lay just beneath the endocardium near the coronary sinus ostium 2) there is a risk of the AVN artery coagulation during radiofrequency ablation in the slow pathway region.

Adult↗

Reduction in treatment delay by paramedic ECG diagnosis of myocardial infarction with direct CCU admission.

OBJECTIVES: To establish the feasibility of training paramedics of diagnose acute myocardial infarction by ECG before hospital admission and whether direct paramedic coronary care admission, arranged by very high frequency (VHF) radio communication with the coronary care unit (CCU), would reduce delay of thrombolysis treatment. DESIGN: Prospective controlled study. SETTING: District general hospital CCU and a local district ambulance paramedic service. PATIENTS: 124 patients with ECG evidence of myocardial infarction or ischaemia admitted directly to the CCU by the paramedic service were compared with 123 patients admitted by the emergency department and subsequently transferred to the CCU. MAIN OUTCOME MEASURES: ECG diagnostic accuracy by paramedics, and interval durations for CCU admission and thrombolysis. RESULTS: ECG diagnostic accuracy by the paramedics was 87.5% in the training phase and 92% in admission. The total call to thrombolysis interval was reduced from 154 to 93 minutes and the "door to needle" interval was reduced from 97 to 37 minutes. CONCLUSIONS: Trained paramedics can reliably diagnose myocardial infarction by ECG. The use of a direct admission procedure, by a VHF radio link to the CCU, substantially reduces the time interval for thrombolytic treatment after acute myocardial infarction.

Adult↗

Inhibition of phosphomannose isomerase by fructose 1-phosphate: an explanation for defective N-glycosylation in hereditary fructose intolerance.

Isoelectrofocusing of serum sialotransferrins from patients with untreated hereditary fructose intolerance (HFI) shows a cathodal shift similar to that in carbohydrate-deficient glycoprotein (CDG) syndrome type I and in untreated galactosemia. This report is on serum lysosomal enzyme abnormalities in untreated HFI that are identical to those found in CDG syndrome type I but different from those in untreated galactosemia. CDG syndrome type I is due to phosphomannomutase deficiency, a defect in the early glycosylation pathway. It was found that fructose 1-phosphate is a potent competitive inhibitor (Ki congruent to 40 microM) of phosphomannose isomerase (EC 5.3.1.8), the first enzyme of the N-glycosylation pathway thus explaining the N-glycosylation disturbances in HFI.

Animals↗

Nutritional complementation of oxidative glucose metabolism in Escherichia coli via pyrroloquinoline quinone-dependent glucose dehydrogenase and the Entner-Doudoroff pathway.

Two glucose-negative Escherichia coli mutants (ZSC113 and DF214) were unable to grow on glucose as the sole carbon source unless supplemented with pyrroloquinoline quinone (PQQ). PQQ is the cofactor for the periplasmic enzyme glucose dehydrogenase, which converts glucose to gluconate. Aerobically, E. coli ZSC113 grew on glucose plus PQQ with a generation time of 65 min, a generation time about the same as that for wild-type E. coli in a defined glucose-salts medium. Thus, for E. coli ZSC113 the Enter-Doudoroff pathway was fully able to replace the Embden-Meyerhof-Parnas pathway. In the presence of 5% sodium dodecyl sulfate, PQQ no longer acted as a growth factor. Sodium dodecyl sulfate inhibited the formation of gluconate from glucose but not gluconate metabolism. Adaptation to PQQ-dependent growth exhibited long lag periods, except under low-phosphate conditions, in which the PhoE porin would be expressed. We suggest that E. coli has maintained the apoenzyme for glucose dehydrogenase and the Entner-Doudoroff pathway as adaptations to an aerobic, low-phosphate, and low-detergent aquatic environment.

Aerobiosis↗

Detergent (sodium dodecyl sulfate) shock proteins in Escherichia coli.

The protein composition of Escherichia coli W3110 grown in the presence and absence of 5% sodium dodecyl sulfate (SDS) was examined by two-dimensional gel electrophoresis. In SDS-grown cells, at least 4 proteins were turned on, 13 were turned off, 15 were elevated, and 15 were depressed. The 19 unique and elevated SDS-induced spots constituted 7.91% of the total 35S-labeled protein. There was no apparent overlap between these 19 detergent (SDS) stress proteins and those of other known bacterial stress responses. The detergent stress stimulon is a distinct and independent stimulon. Its physiological relevance probably derives from the presence of bile salts in animal gastrointestinal tracts.

Bacterial Proteins↗