ACTA ENDOCRINOLOGICA (BUC)

Phenylketonuria (PKU) is the most frequent inherited amino acid metabolic disorder, and it may also be treated by dietary means. The determination of phenylalanine (Phe) levels in the blood plasma is important not only in early diagnostic, but also in monitoring the treatment of PKU. Purpose. The aim of our work was to develop a simple, sensitive and highly accurate procedure to determine the plasma concentration of Phe. Procedure. The measurement of plasma Phe concentration involves two steps: a) separation of plasma (from the blood taken on heparin), isolation and preparation of a concentrated solution of amino acids (by ion-exchange column chromatography on Dowex-50X8 and evaporation of the eluate in vacuum at 40˚C), and b) determination of Phe concentration in the solution of amino acids by HPLC. This analysis was performed using a Dionex Ultimate 3000 instrument equipped with a Ultimate 3000 diode array detector (DAD). The values of Phe concentration in the plasma of several patients were calculated using a calibration curve made with standards of Phe (dilutions of a stock solution of 50 mg/ dL). The measurements in duplicate (plasma Phe) or a greater number of samples from the same concentration of standards of Phe showed extremely small sample to sample differences. Concentrations as low as 0.2 mg/dL could be determined. Conclusion. The whole procedure presented here is relatively simple, rather inexpensive, however very sensitive and highly accurate. Consequently, it is very adequate for confirming the diagnosis of PKU in patients with neonatal hyperphenylalaninemia, as well as for monitoring the plasma concentration of Phe in patients with PKU.

Aim. To correlate the profile of CFTR gene mutations in patients from Romania with the ethnogenesis of Rumanian people. Patients and methods. One hundred sixty-five patients with clinical diagnosis of CF and elevated values at sweat test were included in the study. Samples of EDTA-anticoagulated blood were obtained by venipuncture, sent to our laboratory and DNA was extracted from leukocytes. For the majority of blood samples we used standardized methods for analysis of at least 18 common mutations. Ten DNA samples were analyzed for 38 CFTR mutations with a kit recently introduced in our program of investigations of CFTR gene mutations.Results. The most frequent mutations in CF patients from Romania are F508del (53.6%), G542X (4.6%), W1282X (2.1%) and CFTRdele2,3(21kb) (1.2%). Other mutations were detected at frequencies less than 1.0%. The profile of the CFTR gene mutations in Rumanian patients appears to be very different from its counterpart profile in Romania’s neighbour countries and rather similar with the profile of mutations in France, Italy and Spain (which, similar to Romania, are Neo-Latin countries). A notable difference between Romania and these Neo-Latin countries is the presence of a Slavic mutation, CFTRdele2,3(21kb) in Rumanian patients; this might reflect the Slavic component in the ethnogenesis of Rumanian people.Conclusion. The profile of the CFTR gene mutations in Rumanian patients confirms the overwhelming evidence regarding the ethnogenesis of Rumanian people from the admixture of Dacians or Getae (the ancient autochtonous inhabitants of the territory of present-day Romania) with Roman (or Romanized) legionnaires and colonists, forming the Daco-Roman population (the basis of Rumanian people), who assimilated the Slavs that entered in the territory of present-day Romania in the VIth century.

Developments in the understanding of the molecular basis of water permeability of the red blood cell (RBC) have taken place rapidly since the discovery in 1985 in Cluj- Napoca, Romania, by the group of Benga of a water channel protein (WCP), later called aquaporin 1 (AQP1), in the RBC membrane. However, the physiological role of AQP1 is not yet fully understood. Investigations of RBCs from human subjects of various ages could help shed light on this important issue. We present a short review of our studies on this topic that were published in less “visible” journals and books. The diffusional water permeability (Pd) of the RBC membrane has the lowest values in the newborns. Then Pd values are increasing in children, reaching at about 7 years a value that remains rather constant in young and mature subjects. The high permeability to water of the RBC membrane can be correlated at these ages with the ability to undertake a high level of physical activity. In elderly individuals (over 65 years) a further small, but statistically significant, increase in the diffusional water permeability of RBC was observed. In this case the higher RBC water permeability can be correlated with a requirement of the RBC membrane to favour the membrane undulations and the rapid entry or exit of solutes of molecular size greater than water, in conditions when the organism is less physically active, probably has lower metabolic rates and lower mean rates of blood circulation.