The systemic inflammatory response syndrome as a predictor of bacteraemia and outcome from sepsis

Criteria defining the <it>systemic inflammatory response syndrome</it> (SIRS) were used to assess prospectively 270 clinical episodes in which blood cultures were taken from patients in general medicine. SIRS, severe sepsis and septic shock occurred in 149 (55%), 13 (5%) and 9 (3%) episodes, respectively. However, evidence of organ hypoperfusion indicating severe sepsis was recorded as sought in only 26% of episodes of SIRS. Crude mortality at 28 days increased sequentially as more SIRS criteria were met, rising from 12% in non-SIRS blood culture episodes, to 36% when all four criteria were met. Mortality from severe sepsis and septic shock was 38% and 56%, respectively. In 61/64 (95%) episodes of clinically important bacteraemia, patients fulfilled SIRS criteria when the blood culture was taken. However, the positive predictive value of SIRS for predicting bacteraemia was only 7%. Patients who did not fulfill SIRS criteria when blood cultures were taken were at low risk of bacteraemia and comprised 45% (121/270) of the study population. Three patients in this low-risk group had bacteraemia. Mortality in bacteraemic patients with severe sepsis or septic shock who were initially treated with ineffective antibiotics for up to 48 h was 80%, compared to 42% in those always treated appropriately.      

Surgical bacterial infections and antimicrobial susceptibility patterns at Lilongwe Central Hospital

A cross sectional study was done between October 1999 and February 2000 to determine antimicrobial susceptibility patterns of consecutive bacterial isolates of 102 clinical samples among surgical in-patients at Lilongwe Central Hospital (LCH), Malawi. Antimicrobial susceptibility was determined using comparative disc diffusion techniques. 83 (81.4%) samples were culture positive for bacterial growth while 19 (18.6%) grew nothing. Of the 93 culture positive specimens, Staphylococcus aureus was the predominant organism 43(51.8%) followed by Proteus species 8(9.6%) and E. coli 7(8.4%). Overall, 98.6% of all isolates tested against ciprofloxacin were susceptible, and against gentamicin and flucloxacin were 84.8% and 66.7% respectively. 59.3% of isolates tested against chloramphenicol were resistant. We recommend a review on the use of chloramphenicol as first-line antimicrobial therapy among surgical in-patients at Lilongwe Central Hospital. We also recommend restricted use of antimicrobials so as to minimise development of drug resistance. Periodic susceptibility studies are necessary to guide judicious use of antibiotics.     

Erythropoietin kinetics in rats: generation and clearance

Detailed studies to analyze the early events of erythropoietin (Ep) secretion and clearance were performed in a rat model using a double antibody radioimmunoassay. Ep clearance was determined following intravenous injection of 1 mL of Ep-rich plasma, 1,080 mU/mL, obtained from phlebotomized rats. Analysis revealed a disappearance curve that conformed to a two-compartment model with an alpha half-life t1/2 of 3.6 minutes and a beta t1/2 of 86 minutes. The volume of distribution was similar to the calculated plasma volume. In anephric animals, there was no change in the plasma clearance rate or the volume of distribution. Rapid Ep secretion was elicited by a single 15 mL/kg phlebotomy (hematocrit decrement 45% to 30%), so that levels reached 20 to 30 times baseline (524 +/- 76 v 24 +/- 7 mU/mL) at five hours, whereas they plateaued for at least 33 hours. The increase in the rate of secretion was geometric, from 9.9 mU/h baseline secretion to 429 mU/h. These data identify a very sensitive and rapidly responsive system for Ep modulation in the rat.     

Noninvasive time-dependent cytometry monitoring by digital holography

Using a digital holographic microscope setup, it is possible to measure dynamic volume changes in living cells. The cells were investigated time-dependently in transmission mode for different kinds of stimuli affecting their morphology. The measured phase shift was correlated to the cellular optical thickness, and then of the cell volume as well as the refractive index were calculated and interpreted. For the characterization of the digital holographic microscope setup, we have developed a transparent three-dimensional (3-D) reference chart that can be used as a lateral resolution chart and step-height resolution chart included in one substrate. For the monitoring of living cells, a biocompatible and autoclavable flow chamber was designed, which allows us to add, exchange, or dilute the fluid within the flow chamber. An integrated changeable coverslip enables inverse microscopic applications. Trypsinization, cell swelling and shrinking induced by osmolarity changes, and apoptosis served as model processes to elucidate the potential of the digital holographic microscopy (DHM).