Brazilian guidelines proposal for screening and treatment of retinopathy of prematurity (ROP)

Retinopathy of prematurity is one of the main causes of childhood blindness. Worldwide, there are more than 50,000 children blind due to retinopathy of prematurity. Visual impairment is a consequence of retinal detachment. It can be detected by serial ophthalmologic examination of infants at risk, and those identified with the severe form of the disease can be treated by laser or cryotherapy, which can decrease significantly the blindness due to ROP. The Brazilian Society of Pediatrics, Brazilian Council of Ophthalmology and Brazilian Society of Pediatric Ophthalmology suggest a guideline for the detection and treatment of retinopathy of prematurity in Brazil. This document was based on the results of the I Workshop of Retinopathy of Prematurity and presents the attributes for the implementation of an efficient diagnostic and treatment program.     

Plasminogen activators and their inhibitors in leukemic cell homogenates

Plasminogen activator (PA) and PA inhibitor (PAI) were measured in homogenates of leukemia cells. Both PA and PAI levels were higher in non-lymphoblastic leukemia than in lymphoblastic leukemia. The levels were below the sensitivity of determination in chronic myelocytic leukemia (CML) but showed significant increases in blast crisis (CML, bc). The level of the tissue type PA (t-PA) antigen was highest in acute myelobtestic leukemia (AML) and that of the urokinase type PA (u-PA) was highest in acute promyeiocytic leukemia (APL). The PAH antigen showed no marked cell specificity, but the PAI-II antigen was markedly increased in myelomonocytic leukemia and acute monocytic leukemia (AMoL). From these findings, various PAs and PAIs are considered to be present in leukemia cells and to be involved in hemostatic disorders, thus they are of diagnostic value in leukemia. © 1993 Wiley-Liss, Inc.     

Alveolar Tidal recruitment/derecruitment and Overdistension During Four Levels of End-Expiratory Pressure with Protective Tidal Volume During Anesthesia in a Murine Lung-Healthy Model

Purpose

We compared respiratory mechanics between the positive end-expiratory pressure of minimal respiratory system elastance (PEEP_minErs) and three levels of PEEP during low-tidal-volume (6 mL/kg) ventilation in rats.

Methods

Twenty-four rats were anesthetized, paralyzed, and mechanically ventilated. Airway pressure (P_aw), flow (F), and volume (V) were fitted by a linear single compartment model (LSCM) P_aw(t)?=?E_rs?×?V(t)?+?R_rs?×?F(t)?+?PEEP or a volume- and flow-dependent SCM (VFDSCM) P_aw(t)?=?(E₁?+?E₂?×?V(t))?×?V(t) + (K₁?+?K₂?×?|F(t)|)?×?F(t)?+?PEEP, where E_rs and R_rs are respiratory system elastance and resistance, respectively; E₁ and E₂×?V are volume-independent and volume-dependent E_rs, respectively; and K₁ and K₂?×?F are flow-independent and flow-dependent R_rs, respectively. Animals were ventilated for 1 h at PEEP 0 cmH₂O (ZEEP); PEEP_minErs; 2 cmH₂O above PEEP_minErs (PEEP_minErs+2); or 4 cmH₂O above PEEP_minErs (PEEP_minErs+4). Alveolar tidal recruitment/derecruitment and overdistension were assessed by the index %E₂?=?100?×?[(E₂?×?V_T)/(E₁ + |E₂|?×?V_T)], and alveolar stability by the slope of E_rs(t).

Results

%E₂ varied between 0 and 30% at PEEP_minErs in most respiratory cycles. Alveolar Tidal recruitment/derecruitment (%E₂?<?0) and overdistension (%E₂?>?30) were predominant in the absence of PEEP and in PEEP levels higher than PEEP_minErs, respectively. The slope of E_rs(t) was different from zero in all groups besides PEEP_minErs+4.

Conclusions

PEEP_minErs presented the best compromise between alveolar tidal recruitment/derecruitment and overdistension, during 1 h of low-V_T mechanical ventilation.

     

Pulmonary <Superscript>18</Superscript>F-FDG uptake helps refine current risk stratification in idiopathic pulmonary fibrosis (IPF)

Purpose

There is a lack of prognostic biomarkers in idiopathic pulmonary fibrosis (IPF) patients. The objective of this study is to investigate the potential of ¹⁸F-FDG-PET/ CT to predict mortality in IPF.

Methods

A total of 113 IPF patients (93 males, 20 females, mean age?±?SD: 70?±?9 years) were prospectively recruited for ¹⁸F-FDG-PET/CT. The overall maximum pulmonary uptake of ¹⁸F-FDG (SUV_max), the minimum pulmonary uptake or background lung activity (SUV_min), and target-to-background (SUV_max/ SUV_min) ratio (TBR) were quantified using routine region-of-interest analysis. Kaplan–Meier analysis was used to identify associations of PET measurements with mortality. We also compared PET associations with IPF mortality with the established GAP (gender age and physiology) scoring system. Cox analysis assessed the independence of the significant PET measurement(s) from GAP score. We investigated synergisms between pulmonary ¹⁸F-FDG-PET measurements and GAP score for risk stratification in IPF patients.

Results

During a mean follow-up of 29 months, there were 54 deaths. The mean TBR?±?SD was 5.6?±?2.7. Mortality was associated with high pulmonary TBR (p?=?0.009), low forced vital capacity (FVC; p?=?0.001), low transfer factor (TLCO; p?<?0.001), high GAP index (p?=?0.003), and high GAP stage (p?=?0.003). Stepwise forward-Wald–Cox analysis revealed that the pulmonary TBR was independent of GAP classification (p?=?0.010). The median survival in IPF patients with a TBR < 4.9 was 71 months, whilst in those with TBR?> 4.9 was 24 months. Combining PET data with GAP data (“PET modified GAP score”) refined the ability to predict mortality.

Conclusions

A high pulmonary TBR is independently associated with increased risk of mortality in IPF patients.

     

Time course of respiratory mechanics and pulmonary structural remodelling in acute lung injury

The aim of this study was to evaluate the time course of in vivo and in vitro respiratory mechanics and examine whether these parameters could reflect the temporal changes in lung parenchyma remodelling in paraquat (PQ)-induced lung injury. Measurements were done 1, 3 and 8 weeks after the intraperitoneal (i.p.) injection of saline (control) or paraquat (7mgkg(-1)) in rats. Airway and tissue resistances increased from control in PQ1 and PQ3 and returned to control values in PQ8, in accordance with the magnitude of bronchoconstriction. Viscoelastic/inhomogeneous pressure, tissue elastance, the number of polymorphonuclear cells, and collagen fibre content in lung parenchyma increased in PQ1 and remained elevated in PQ3 and PQ8. Static elastance increased in PQ1, returned to control values after 3 weeks, and was correlated with the volume fraction of collapsed alveoli. In conclusion, there is a restoration of normal alveolar-capillary lung units with a gradual improvement in airway and tissue resistances and static elastance. However, the on-going fibrotic process kept elevated tissue elastance and viscoelastic/inhomogeneous pressure.     

From morphology to molecular biology: can we use sequence data to identify fungal endophytes?

Isolation followed by morphological identification was the traditional basis of all earlier endophyte studies. However, the use of molecular phylogenetics has become increasingly common in the identification of fungal endophytes, and during the period of 2007–2010 there were approximately 200 publications that reported data obtained using this approach. This new methodology involves using sequence data from isolates or whole DNA from plant substrates, which are amplified using fungus- specific primers. The data obtained are compared with sequences downloaded from public databases such as GenBank and then used to construct phylogenetic trees. The major problem with this approach is that much of the sequence data in these databases has been shown to be from isolates that were incorrectly named. In some species, as much as 86% of the sequences available are not from the organism whose name has been applied to the sequence in question. The use of these GenBank sequences to identify endophytic isolates by sequence similarity simply perpetuates the problem of wrong species identification, and any lists of endophytes established by such methods are likely to be highly erroneous. It is recommended that comparisons of sequence data be made using sequences from type species, and if such sequences are not available, then the data must be treated with caution.