Thermolysin and α-chymotrypsin mediated synthesis of tripeptides containing proline

The tripeptides Z-Pro-Leu-Gly-OEt, Z-Pro-Leu-Gly-NH₂ and Z-Pro-Leu-Gly-OBzl were synthesized by thermolysin and α-chymotrypsin catalysis. The optimum conditions for the couplings between Z-Pro-OH and H-Leu-OEt or H-Leu-Gly-OEt catalysed by thermolysin were determined by a systematic study involving analysis of pH effect, ammonium sulfate concentration, reaction time, enzyme concentration, and relative proportion of the carboxyl and amine components. The best yield obtained for Z-Pro-Leu-OEt was 77% and for Z-Pro-Leu-Gly-OEt, 100%. Z-Pro-Leu-OEt was coupled to H-Gly-OEt, H-Gly-NH₂ and H-Gly-OBzl. The best conditions to obtain Z-Pro-Leu-Gly-OEt and Z-Pro-Leu-Gly-NH₂ were determined by the study of some factors that affect the reaction yield, such as organic solvent presence, substrate ratio and aqueous and organic solvent ratio. The yield obtained under optimum synthesis conditions was 55% for Z-Pro-Leu-Gly-OEt and 61% for Z-Pro-Leu-Gly-NH₂. Z-Pro-Leu-Gly-OBzl was synthesized with 42% yield.     

Antibodies against Echinococcus multilocularis alkaline phosphatase as markers for the specific diagnosis and the serological monitoring of Alveolar echinococcosis

The immunological properties of the purified alkaline phosphatase (pAP) of Echinococcus multilocularis metacestodes have been investigated using alveolar echinococcosis (AE) patient sera in ELISA tests. A comparative study was done with EmC-Ag (crude antigen) and pAP-Ag (purified antigen). When the parasite purified enzyme pAP was used as antigen, the specificity of the ELISA was markedly increased since it reached 100% without any decrease of its sensitivity (100%). The serologic follow-up of AE patients was conducted during several months with these two antigens in three categories of patients: cured, stabilized and aggravated. There was a good correlation between clinical and serologic data when the pAP was used as antigen in ELISA tests. The anti-pAP antibodies titres did change more rapidly than anti-EmC antibodies titres when a recurrence occurred. Modifications of the anti-pAP antibodies levels were also observed during the patient's therapy: mebendazole, albendazole and Isoprinosine^®. These results suggest that pAP-Ag should be used for the diagnosis and the follow-up of AE patients.     

Demonstration of Enolase Activity Connected to the Brain-Specific Protein 14-3-2

An enzyme activity, enolase (2-phospho-D-glycerate hydro-lyase, E.C. 4.2.1.11), was shown to be connected to the brain-specific protein 14.3.2. Specific staining methods were used on immuno precipitates of the protein. The enzyme activity was strongly inhibited by the addition of fluoride in the presence of phosphate. Metal ion binding capacity of the protein was shown by means of an auto radiographic method.     

Histochemical demonstration of activity of acid phosphatase and β-glucuronidase in bovine incisor tooth germs

Abstract – Activity of acid phosphatase and β-glucuronidase was shown in bovine preodontoblasts and preameloblasts prior to the onset of secretion. In the preameloblasts the rather weak reaction consisted of small discrete granules dispersed in the cytoplasm apical, lateral, and proximal to the nucleus. After initiation of enamel formation, a change in localization and intensity of the colored reaction product was observed in the ameloblasts. The activity appeared stronger and was restricted to a narrow zone just apical to the nucleus. It is proposed that the acid hydrolases in the tooth forming cells are located to the Golgi complex. The differences in activity of acid hydrolases between bone and tooth forming cells are expounded.     

Porphyria cutanea tarda (PCT) in a patient with chronic renal failure on haemodialysis

Porphyria cutanea tarda, diagnosed by reduced levels of red cell uroporphyrin decarboxylase and raised plasma porphyrins, developed in a patient with chronic renal failure due to polycystic kidneys, treated with haemodialysis, who had normal total urinary and faecal porphyrins. Haemodialysis did not alter plasma porphyrin levels and we deduced that most of the plasma porphyrins were circulating in high molecular weight protein complexes.     

Clinical Impact of an Open‐Irrigated Radiofrequency Catheter with Direct Force Measurement on Atrial Fibrillation Ablation

Background: Electrode‐tissue contact is crucial for adequate lesion formation in radiofrequency catheter ablation (RFCA). Objective: We assessed the impact of direct catheter force measurement on acute procedural parameters during RFCA of atrial fibrillation (AF). Methods: Fifty consecutive patients (28 male) with paroxysmal AF who underwent their first procedure of circumferential pulmonary vein (PV) isolation (PVI) were assigned to either RFCA using (1) a standard 3.5‐mm open‐irrigated‐tip catheter or (2) a catheter with contact force measurement capabilities. Using the endpoint of PVI with entry and exit block, acute procedural parameters were assessed. Results: Procedural data showed a remarkable decline in ablation time (radiofrequency time needed for PVI) from 50.5 ± 15.9 to 39.0 ± 11.0 minutes (P = 0.007) with a reduction in overall procedure duration from 185 ± 46 to 154 ± 39 minutes (P = 0.022). In parallel, the total energy delivered could be significantly reduced from 70,926 ± 19,470 to 58,511 ± 14,655 Ws (P = 0.019). The number of acute PV reconnections declined from 36% to 12% (P = 0.095). Conclusions: The use of contact force sensing technology is able to significantly reduce ablation and procedure times in PVI. In addition, energy delivery is substantially reduced by avoiding radiofrequency ablation in positions with insufficient surface contact. Procedural efficacy and safety of this new feature have to be evaluated in larger cohorts. (PACE 2012; 35:1312–1318)