Ecology of inland sand dunes “nafuds” as a hyper-arid habitat,Saudi Arabia: Floristic and plant associations diversity

Sand seas of Saudi Arabia cover about one-third of the Arabian Peninsula and are still poorly explored in scientific literature. This study aimed to address the floristic structure and association diversity of the inland sand seas in central Saudi Arabia after 20 years of protection. Twenty-three relevés were selected in Nafud Al-Urayq reserve to cover different sandy dune variations. These relevés are subjected to floristic and multivariate analysis of classification with TWINSPAN and ordination with DECORANA & CANOCO techniques. One hundred thirty-five species belonging to 108 genera in 37 families have been recorded. Annual and perennial species are equally represented. Four vegetation groups (i.e., plant associations) are identified as the following: VG I (Haloxylon salicornicum-Lycium shawii-Acacia raddiana), VG II (Calligonum comosum-Tetraena propinqua), VG III (Haloxylon persicum-Haloxylon salicornicum-Stipagrostis drarii), and VG IV (Pulicaria undulata-Citrullus colocynthis). The association of VG I inhabited in the wadi and non-dune or shallow sand habitat had the high species diversity indices (i.e., total species, species richness, species evenness and Shannon index). In contrast, the association of VG II inhabited hyper-arid and salinized habitat and had low species diversity indices. These associations are discussed and illustrated in accordance with competition and adaptation. The advantages of inland sand dune vegetation therefore apply specifically to habitat management and the conservation of plants. These studies extend the advantages of succession of sand dunes and show that rising vegetative diversity is consistent with the combat of desertification.     

Insulin Glargine in the intensive care unit: A model-based clinical trial design

IntroductionCurrent successful AGC (Accurate Glycemic Control) protocols require extra clinical effort and are impractical in less acute wards where patients are still susceptible to stress-induced hyperglycemia. Long-acting insulin Glargine has the potential to be used in a low effort controller. However, potential variability in efficacy and length of action prevent direct in-hospital use in an AGC framework for less acute wards.MethodClinically validated virtual trials based on data from stable ICU patients from the SPRINT cohort who would be transferred to such an approach are used to develop a 24-h AGC protocol robust to different Glargine potencies (1.0×, 1.5× and 2.0× regular insulin) and initial dose sizes (dose = total insulin over prior 12, 18 and 24 h). Glycemic control in this period is provided only by varying nutritional inputs. Performance is assessed as %BG in the 4.0–8.0 mmol/L band and safety by %BG < 4.0 mmol/L.ResultsThe final protocol consisted of Glargine bolus size equal to insulin over the previous 18 h. Compared to SPRINT there was a 6.9–9.5% absolute decrease in mild hypoglycemia (%BG < 4.0 mmol/L) and up to a 6.2% increase in %BG between 4.0 and 8.0 mmol/L. When the efficacy is known (1.5× assumed) there were reductions of: 27% BG measurements, 59% insulin boluses, 67% nutrition changes, and 6.3% absolute in mild hypoglycemia.ConclusionBased on current understanding of Glargine behaviour, a robust protocol for a 24–48 clinical trial has been designed to safely investigate possible differences in efficacy and kinetics of Glargine in a critically ill population. This protocol is a first step towards developing a Glargine-based protocol for less acute wards. Ensuring robustness to variability in Glargine efficacy directly affects the performance and safety that can be obtained.     

Resistance of Pseudomonas pseudomallei to Normal Human Serum Bactericidal Action

The effect of human normal serum (HNS) on Pseudomonas pseudomallei was determined. It is apparent from our data that the organism is resistant to the normal serum bactericidal mechanism. Ancillary experiments to confirm this serum-resistant property of P. pseudomallei were done by examining the effects of growth phase conditions of the bacteria (i.e., logarithmic and stationary phases) and different buffered systems used as diluent in our bactericidal assay. Results obtained showed similar degree of resistance to serum bactericidal killing by 5 strains of the organisms tested. The possible survival advantage of serum-resistant property to P. pseudomallei as bacterial pathogens known to invade the blood stream is discussed.