Composition and Conformation of Hetero- versus Homo-Fluorinated Triazolamers Influence their Activity on Islet Amyloid Polypeptide Aggregation

Novel fluorinated foldamers based on aminomethyl-1,4-triazolyl-difluoroacetic acid (1,4-Tz-CF2) units were synthesized and their conformational behaviour was studied by NMR and molecular dynamics. Their activity on the aggregation of the human islet amyloid polypeptide (hIAPP) amyloid protein was evaluated by fluorescence spectroscopy and mass spectrometry. The fluorine labelling of these foldamers allowed the analysis of their interaction with the target protein. We demonstrated that the preferred extended conformation of homotriazolamers of 1,4-Tz-CF2 unit increases the aggregation of hIAPP, while the hairpin-like conformation of more flexible heterotriazolamers containing two 1,4-Tz-CF2 units mixed with natural amino acids from the hIAPP sequence reduces it, and more efficiently than the parent natural peptide. The longer heterotriazolamers having three 1,4-Tz-CF2 units adopting more folded hairpin-like and ladder-like structures similar to short multi-stranded β-sheets have no effect. This work demonstrates that a good balance between the structuring and flexibility of these foldamers is necessary to allow efficient interaction with the target protein.

5-Fluoro-1,2,3-triazole motif in peptides and its electronic properties

The 5-fluoro triazole amino acid has been prepared by halogen exchange between the 5-iodo triazole and fluoride salts and incorporated in peptides. X-ray crystallography reveals a cylindrical shape in its deformation electron density.

Fluorinated Triazole Foldamers: Folded or Extended Conformational Preferences

The Ministère de l'Enseignement Supérieur et de la Recherche (MESR) is thanked for financial support for José Laxio Arenas. The China Scholarship Council is thanked for financial support for Yaochun Xu. The authors thank Pr. Vadim Soloshonok and TOSOH F-TECH, Inc. for the kind gift of N-terbutyl-sulfinylimine.

[Normal values in Mexico of the echocardiographic measurements of the left heart]

The M-Mode echocardiographic measurements, according to the international criteria, were done in tracings of 274 normal subjects residents of Mexico City, in order to know the normal values in its population. One hundred and thirty one males (47.8%), and 143 females (52.2%). The age varied from 1 to 73 years, the predominant group was between the third and fifth decades of the life. The age, weight and body surface area (BSA) were correlated with measurements, better correlation was found with BSA and it was the analysis base. According to the BSA, 6 subgroups were formed, the first one of 0.5 m2; increasing 0.4 m2 for each subgroup until the last one of 2.1(2) or more. Were observed proportional amount respect to BSA of D-E mitral valve excursion, aortic root diameter, aortic excursion, aortic opening amplitude, left atrium diameter, end diastolic and end systolic diameters of left ventricle, as well as interventricular septum (IVS) and posterior wall (PW) thickness. The measures were less than the reported other countries. The mean velocity of circumferential shortening (Vcf), fractional shortening (FS) and normalized velocities (NV) showed inverse proportion to BSA. The values of Vcf and NV were similar to the previous report, but the FS and the ejection fraction were higher. The study let us to know the normal echocardiographic values for people of Mexico and the differences with respect to the altitude of this city and the body frame of its population.

[Valve replacement using an artificial ball prosthesis manufactured in Mexico]

This report documents our early experience with a cage ball valve manufactured in Mexico. Between May 1985 and March, 1986, 25 consecutive replacements have been performed in 23 patients, 14 underwent aortic valve replacement, 9 received a mitral valve, and 2 received both aortic and mitral valves. Their mean age was 32 years. Most of the patients had rheumatic heart disease. Their functional class prior to operation was as follows: six patients fell into class II, 15 into class III and 2 into class IV. One case died in the operative period. All patients have been followed for a mean period of 5 months. Late mortality has not occurred in any patient. Valve-related complications were not present. The post-operative NYHA functional class was as follows: seventeen (80%) fell into class I and five (20%) fell into class II. The actuarial survival rate 10 months after operation was 96.0%. Our study suggests that the cage ball valve has a good performance, the clinical results justify continuing investigation of this prosthesis.

[Echocardiographic study of valvular prosthesis]

Eighty-six patients with valvular prosthesis (PV) were included in this study, 52 females and 34 males, from 9 to 55 years of age. The functional state of the PV was corroborated with catheterization, surgery or necropsy. The results of 92 PV were analyzed, of which 72 were in mitral position, including 49 dura mater valves (DMPV). In aortic position were 18, including 12 mechanical Bjork-Shilley (BS) and 2 in tricuspid position. The prostheses were classified in three groups: I. with regurgitation, II. with obstruction and III. without dysfunction. Of the 49 DMPV in mitral position 11 were in group I and 7 in group II. The echocardiogram revealed a diminished opening velocity in group II (255 +/- 41.2 mm/sec., P less than 0.001) as well as a diminished opening excursion (10.9 +/- 3.4 mm, P less than 0.02) and increased thickness of the leaflets (4.7 +/- 3.6 mm, P less than 0.05). Paradoxical interventricular septal movement was less frequent in group I (27.2%, P less than 0.05). Seventeen BS valves were in mitral position; of these 2 were classified in group I and the rest in group III, the opening velocity was increased (1200 mm/sec) in those of group I. None of the BS valves in aortic position were dysfunctional. No patients from group III died; mortality in groups I and II was 35%. In 5.1% of group III and 20% of groups I and II either no improvement or greater clinical deterioration was observed.

[2-dimensional echocardiographic measurement of the valvular area in mitral stenosis. Surgical correlations]

The calculation of mitral valve orifice area in patients with mitral stenosis is important because it establish the surgical indication and the type of surgical procedure to be done (commisurotomy, valvuloplasty or valve replacement). Moreover, the postoperative measurement of the mitral orifice area may be useful to evaluate the surgical results and to differentiate between inadequate commisurotomy and restenosis. We studied 12 patients with measurement of mitral orifice area by two-dimensional echocardiography imaging and digital microproccesing. The measurements were compared with the surgeon's estimate. The correlation obtained was of r = 0.86 (p less than or equal to 0.05). The description of the surgeon corroborated the echocardiographic findings respecting mitral subvalvular apparatus in all except one patient. Concerning the thickening of the values, echocardiographic and surgical findings were concordant in 10 patients. The mitral orifice area showed inverse relationship with pulmonary artery wedge pressure measured by catheterization in 5 patients (r = -0.844). After commisurotomy, the mitral orifice area was analyzed in 9 patients, since one patient requerired valve replacement and in two we did not obtain echocardiographic studies. The postoperative increase of the mitral orifice area was significant; (before surgery X 0.6 cm2 +/- 0.16) and after surgery (X 2.7 cm2 +/- 0.22) p less than or equal to 0.001).

[Radiologic indices and measurements in the evaluation of pulmonary artery hypertension in chronic obstructive lung disease]

Radiologic indexes proposed as useful in the non-invasive evaluation of pulmonary arterial hypertension (HAP) were analyzed in a group of 35 patients with stable chronic obstructive pulmonary disease (NOC) and secondary HAP (mean pulmonary artery pressure = 29 +/- 2 mmHg). Indices included the PL/T (L = point of union of the external border of the upper lobe artery with the pars interlobaris; PL = the sum of horizontal distances of the right and left L's to the midline: T = transverse diameter of the thorax), the width of the right pulmonary artery at the pars interlobaris (R) and the relation between R and the transverse diameter of the hemithorax (R/H). Our results were as follows: R index was abnormal (greater than 17 mm) in 25 out of 35 patients (71%). PL/T was found abnormal (greater than 38%) in 16 of the patients (45.7%). R/H was abnormal in 10 of the patients (28%). There was no correlation between any of the indexes, and the levels of HAP or pulmonary arteriolar vascular resistance nor the magnitude of lung over inflation or bronchial obstruction. We conclude that the proposed indexes are also of value in NOC with HAP. The width of the right pulmonary artery (R) will be abnormal in two-thirds of the cases with HAP and NOC.