Reliability of maximal respiratory nasal pressure tests in healthy young adults.

INTRODUCTION: Sniff nasal inspiratory (SNIP) and expiratory pressure (SNEP) may complement the assessment of respiratory muscle strength. Thus, specifying their reliability is relevant to improving the clinical consistency of both tests. OBJECTIVE: To assess the reliability of SNIP and SNEP in healthy young adults. METHODS: This cross-sectional study included self-reported healthy aged 18 to 29 years. SNIP was performed using a plug to occlude one nostril, while SNEP was conducted using a facemask. Participants performed 20 SNIP and SNEP maneuvers with 30-second intervals in between. The intraclass correlation coefficient (ICC), standard error of measurement (SEM), and minimum detectable change (MDC) assessed the reliability of SNIP and SNEP. Analyses were conducted between the highest peak pressure and the first reproducible maneuver in men and women. RESULTS: The total sample comprised 32 participants: 16 men and 16 women. The ICC, SEM, and MDC for SNIP maneuvers were 0.994 (95%CI 0.988 to 0.997), 1.820 cmH2O, and 5.043 cmH2O, respectively. For SNEP, these parameters were 0.950 (95%CI 0.897 to 0.976), 6.03 cmH2O, and 16.716 cmH2O. The SNIP and SNEP in men showed ICC of 0.992 (95%CI 0.977 to 0.997) and 0.877 (95%CI 0.648 to 0.957), SEM of 2.07 and 7.66 cmH2O, and MDC of 5.74 and 21.23 cmH2O. In women, SNIP and SNEP presented ICC of 0.992 (95%CI 0.977 to 0.997) and 0.957 (95%CI 0.878 to 0.985), SEM of 1.15 and 6.11 cmH2O, and MDC of 3.19 and 16.95 cmH2O. Also, 60% of the highest SNIPs occurred among the 11th and 20th maneuvers in men and women. In men, 55% of the highest SNEPs occurred among the 11th and 20th maneuvers; this value was 50% in women. CONCLUSION: SNIP and SNEP showed excellent reliability. The reliability of SNIP and SNEP in men was good and excellent, respectively, whereas both tests had excellent reliability in women. Also, women reached the highest peak pressure faster than men in both tests.

Catalytic properties of recombinant dipeptidyl carboxypeptidase from Escherichia coli: a comparative study with angiotensin I-converting enzyme.

Dipeptidyl carboxypeptidase from Escherichia coli (EcDcp) is a zinc metallopeptidase with catalytic properties closely resembling those of angiotensin I-converting enzyme (ACE). However, EcDcp and ACE are classified in different enzyme families (M3 and M2, respectively) due to differences in their primary sequences. We cloned and expressed EcDcp and studied in detail the enzyme's S(3) to S(1)' substrate specificity using positional-scanning synthetic combinatorial (PS-SC) libraries of fluorescence resonance energy transfer (FRET) peptides. These peptides contain ortho-aminobenzoic acid (Abz) and 2,4-dinitrophenyl (Dnp) as donor/acceptor pair. In addition, using FRET substrates developed for ACE [Abz-FRK(Dnp)P-OH, Abz-SDK(Dnp)P-OH and Abz-LFK(Dnp)-OH] as well as natural ACE substrates (angiotensin I, bradykinin, and Ac-SDKP-OH), we show that EcDcp has catalytic properties very similar to human testis ACE. EcDcp inhibition studies were performed with the ACE inhibitors captopril (K(i)=3 nM) and lisinopril (K(i)=4.4 microM) and with two C-domain-selective ACE inhibitors, 5-S-5-benzamido-4-oxo-6-phenylhexanoyl-L-tryptophan (kAW; K(i)=22.0 microM) and lisinopril-Trp (K(i)=0.8 nM). Molecular modeling was used to provide the basis for the differences found in the inhibitors potency. The phylogenetic relationship of EcDcp and related enzymes belonging to the M3 and M2 families was also investigated and the results corroborate the distinct origins of EcDcp and ACE.

Molecular characterization of VP4 and NSP4 genes from rotavirus strains infecting neonates and young children in Belém, Brazil.

Several reports have identified P[6] specificities in humans and in animals in different countries of the world, but few sequence data are available in public databases. In this work we have characterized the VP4 strains bearing P[6] specificity and NSP4 genotypes among diarrheic young children and diarrheic and non-diarrheic neonates from three studies previously conducted in Belém, Northern region of Brazil. As the to VP8* fragment, we observed a close relationship to both human prototypes of lineage P[6]-Ia (bootstrap of 99%) and porcine sublineages Ib and Ic (89.2-98.1% aa similarity and mean of 95%). With regards to the NSP4, the samples clustered into genotypes A and B. Of note, of the 27 P[6] strains analyzed in the present study and classified as genotype B, 8 (29.6%) were more similar to porcine prototypes when VP8* and NSP4 genes are compared, and were recovered, one from a neonate and seven from diarrheic children. These preliminary findings reinforce that further investigations are needed to assess the relative frequencies of P[6] strains in our region, as well as to investigate the potential for interspecies transmission involving humans and animals, particularly pigs.

Detection of a neonatal human rotavirus strain with VP4 and NSP4 genes of porcine origin.

A human rotavirus strain (NB-150) was detected in stool samples from a neonate hospitalized for mild/moderate community-acquired diarrhoea. This baby lived in the outskirts of Belém, Brazil, under poor sanitation conditions. The NB-150 strain displayed a typical long electrophoretic pattern with 11 gene segments. It had two VP7 alleles, G1 and G4, and belonged to VP6 subgroup II. A close relatedness with human rotaviruses was shown for VP7 alleles: G1 (96.9-100 % similarity at the amino acid level) and G4 (97.1-100 % similarity at the amino acid level). As for VP6, 95.1-97.5 % similarity at the amino acid level was noted. VP8* and NSP4 genes showed a close relatedness with those of porcine rotavirus strains, as follows: VP8* (95.0 % similarity at the amino acid level) and NSP4 (93.7-96.0 % similarity at the amino acid level). This is believed to be the first report in Brazil of a rotavirus infection involving a strain with G1 and G4 alleles, with VP8* and NSP4 genes of porcine origin. These findings strongly suggest the occurrence of interspecies transmission.

Molecular analysis of VP4, VP7, and NSP4 genes of P[6]G2 rotavirus genotype strains recovered from neonates admitted to hospital in Belém, Brazil.

This investigation describes the molecular characterization of P[6]G2 rotavirus strains from hospitalized neonates with community-acquired diarrhea (CAD), nosocomial diarrhea (ND), and asymptomatic nosocomial infection (ANI) in Belém, Brazil. Twenty-six rotavirus strains with P[6]G2 genotype were sequenced to genes coding for VP4, VP7, and NSP4 proteins. Phylogenetic analysis of the VP4 gene, including prototype strains RV3, ST3, M37, and U1205, showed that local P[6]G2 strains clustered forming a distinct lineage (bootstrap of 99%). Brazilian P[6]G2 strains had the highest homology (ranging from 96.0%-98.3%) with the African strain GR1107, G4P[6]. Phylogenetic tree for VP7 gene was constructed including old and new G2 African strains SA3958GR/97, SA356PT/96, SA514GR/87, SA4476PT/97, BF3676/99, GH1803/99, and representative strains of G1, G3, G4, G5, G8, and G9 genotypes. The Brazilian P[6]G2 samples fell into a distinct group (bootstrap value of 97%) and showed homology rates ranging from 92.1% to 93.5% with P[6]G2 African strains BF3676/99, GH1803/99, and SA3958GR/97. Nucleotide sequence analysis of the NSP4 gene, including human prototype strains S2, KUN, DS-1, RV5, RV3 and ST3, and animal prototype OSU, showed that all neonatal isolates fell into genotype A and clustered with a bootstrap value of 100%, with in-group similarities ranging from 99.3% to 100%. In this study no significant differences in nucleotide sequences of the VP4, VP7, and NSP4 genes could be observed when comparing diarrheic (CAD and ND) and non-diarrheic (ANI) babies. Monitoring of rotavirus strains in hospital environments is of particular importance, since it is claimed currently that an efficacious rotavirus vaccine, when available for routine use, will determine an impact on hospital-acquired rotavirus disease.