Relationship between collagen fibril diameters and body size

Summary Suspensions of collagen fibrils obtained from derma of Elasmobranchia and Actinopterygia of different body sizes and developmental stages were examined by transmission electron microscopy. Fibril diameters were measured and classified into groups comprising a 20 nm diameter interval. Diagrams showing fibril populations of each fish were made. The measurements were averaged and their confidence intervals and standard errors determined. For each species other diagrams were plotted in which the mean diameters were correlated to the body length of each sample. The results show that: 1) a correlation exists between an increase in diameter of collagen fibrils and somatic growth until sexual maturity is reached; 2) fibril populations are subsequently spread over a wider range due to the presence in the derma of classes of newly formed and therefore thinner fibrils. The deposition of new fibrils is possibly influenced by individual factors; 3) no relationship exists between mean fibril diameter and body size; 4) no relationship exists between phylogenetic position and pattern of diameter distribution.Research supported by a grant from C.N.R. Roma (69.02087.0115.1150)     

Anti-human immunodeficiency virus type 1 humoral immune response and highly active antiretroviral treatment

Highly active antiretroviral treatment (HAART) of human immunodeficiency type 1 (HIV-1) infection is very effective in controlling infection, but elimination of viral infection has not been achieved as yet, and upon treatment interruption an immediate rebound of viremia is observed. A combination of HAART with an immune stimulation might allow treatment interruption without this rebounding viremia, as the very low viremias observed with successful HAART may be insufficient to permit maintenance of a specific anti-HIV-1 immune response. The objective of this study was to compare the humoral immune response of individuals undergoing successful HAART (NF=no failure) with that of individuals with evidence of failure of therapy (FT) and to verify if the viremia peaks observed in individuals with therapy failure would act as a specific stimulus for the humoral anti-HIV-1 immune response. Antibodies binding to gp120 V3 genotype consensus peptides were more frequently observed for FT, mainly against peptides corresponding to sequences of genotypes prevalent in the Rio de Janeiro city area, B and F. HIV-1 neutralization of HIV-1 IIIB and of four primary isolates from Rio de Janeiro was less frequently observed for plasma from the NF than the FT group, but this difference was more expressive when plasma from individuals with detectable viremia were compared to that of individuals with undetectable viral loads in the year before sample collection. Although statistically significant differences were observed only in some specific comparisons, the study indicates that presence of detectable viremia may contribute to the maintenance of a specific anti-HIV-1 humoral immune response.     

Comparing the prognostic accuracy for all-cause mortality of frailty instruments: a multicentre 1-year follow-up in hospitalized older patients

Background

Frailty is a dynamic age-related condition of increased vulnerability characterized by declines across multiple physiologic systems and associated with an increased risk of death. We compared the predictive accuracy for one-month and one-year all-cause mortality of four frailty instruments in a large population of hospitalized older patients in a prospective multicentre cohort study.

Methods and Findings

On 2033 hospitalized patients aged ≥65 years from twenty Italian geriatric units, we calculated the frailty indexes derived from the Study of Osteoporotic Fractures (FI-SOF), based on the cumulative deficits model (FI-CD), based on a comprehensive geriatric assessment (FI-CGA), and the Multidimensional Prognostic Index (MPI). The overall mortality rates were 8.6% after one-month and 24.9% after one-year follow-up. All frailty instruments were significantly associated with one-month and one-year all-cause mortality. The areas under the receiver operating characteristic (ROC) curves estimated from age- and sex-adjusted logistic regression models, accounting for clustering due to centre effect, showed that the MPI had a significant higher discriminatory accuracy than FI-SOF, FI-CD, and FI-CGA after one month (areas under the ROC curves: FI-SOF = 0.685 vs. FI-CD = 0.738 vs. FI-CGA = 0.724 vs. MPI = 0.765, p<0.0001) and one year of follow-up (areas under the ROC curves: FI-SOF = 0.694 vs. FI-CD = 0.729 vs. FI-CGA = 0.727 vs. MPI = 0.750, p<0.0001). The MPI showed a significant higher discriminatory power for predicting one-year mortality also in hospitalized older patients without functional limitations, without cognitive impairment, malnourished, with increased comorbidity, and with a high number of drugs.

Conclusions

All frailty instruments were significantly associated with short- and long-term all-cause mortality, but MPI demonstrated a significant higher predictive power than other frailty instruments in hospitalized older patients.     

Is coarse woody debris in lakes a refuge or a trap for benthic invertebrates exposed to fish predation?

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A TonB-dependent outer membrane protein as a Bacteroides fragilis fibronectin-binding molecule

The binding of Bacteroides fragilis to plasmatic fibronectin was investigated using strains isolated from healthy subjects and from patients with bacteremia. They were cultivated in a synthetic media in which variations in cysteine concentrations determined alterations in the oxidation–reduction potential (Eh). All the strains assayed were capable of adhering to plasmatic fibronectin when cultivated under oxidizing and reducing conditions. Bacteroides fragilis 1405 showed the greatest difference when the results under these conditions were compared and it was selected for further investigations. Chemical treatments suggested the involvement of a protein in the interaction between B. fragilis and plasmatic fibronectin. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis of outer membrane proteins (OMPs) revealed differences between the extracts obtained from cultures grown under the two conditions. Protein bands of c . 102, 100, 77, 73, 50 and 40 kDa were more highly expressed under oxidizing than reducing conditions. Dot blot analysis showed a stronger recognition of plasmatic fibronectin by OMPs obtained from cultures grown under higher Eh, and Western blot assays confirmed a band of c . 102 kDa as fibronectin-binding protein. This protein was sequenced and revealed to be a putative TonB-dependent OMPs. PCR analysis confirmed the presence of this gene in all the studied strains.     

Human immunodeficiency virus type 1 neutralization by plasma from B or F genotype infected individuals

Anti-human immunodeficiency virus type 1 (HIV-1) "binding antibodies" (antibodies capable of binding to synthetic peptides or proteins) occur throughout HIV-1 infection, are high-titered and highly cross-reactive, as confirmed in this study by analyzing plasma from B and F genotype HIV-1 infected individuals. Plasma from individuals infected with clade F HIV-1 displayed the most frequent cross-reactivity, in high titers, while Bbr plasma showed much higher specificity. Similarly, neutralization of a reference HIV-1 isolate (HIV-1 MN) was more frequently observed by plasma from F than B genotype infected individuals. No significant difference was seen in neutralization susceptibility of primary B, Bbr or F clade HIV-1 by plasma from individuals infected with the classical B (GPGR) or F HIV-1, but Bbr (GWGR) plasma were less likely to neutralize the F genotype primary HIV-1 isolates. The data indicate that both B and F genotype derived vaccines would be equally effective against B and F HIV-1 infection, with a slightly more probable effectiveness for F than B genotype. Although the Bbr variant appears to induce a much more specific humoral immune response, the susceptibility in neutralizing the Brazilian HIV-1 B genotype Bbr variant is similar to that observed with the classical B genotype HIV-1.