Absolute value of access flow (QA) and change in flow (deltaQA) over time are major determinants of access patency. However, QA may change in response to variation in systemic hemodynamics among dialysis sessions. We examined the effect of mean arterial pressure (MAP), cardiac output (CO), and segmental resistances (R) on QA. Access flow and CO (L/min) were determined by Transonic ultrasound dilution. Static intra-access pressures (mm Hg) at the arterial segment (AS) and venous segment (VS) were determined with the access unoccluded. During access occlusion (O), the AS pressure was equated to arterial pressure (MAPo), whereas the VS pressure reflected venous pressure (VP). Total and segmental vascular resistances (mm Hg-min/L) were calculated as deltaP/Q. We studied 58 arteriovenous (AV) grafts and 35 autologous AV fistulae (AVF) with measurements on two or more occasions in 43 grafts and 25 AVF. MAPC differed from MAPo by >20 mm Hg in 22% of patients. AS (58 +/- 2 vs. 31 +/- 2) and VS (40 +/- 1 vs. 25 +/- 2) were greater in grafts than in AVF, whereas VP was equal. Access flow (0.91 +/- 0.03 vs. 0.91 +/- 0.05 L/min), cardiac output (5.1 +/- 0.1 vs. 5.5 +/- 0.2 L/min), and total access resistance (115 +/- 5 vs. 11 +/- 6) were equal in grafts and AVF, but non-access systemic R was lower in patients with AVF that those with grafts (26 +/- 1 vs. 30 +/- 1). AS and VS resistances were greater in AVF than grafts (87 +/- 6 vs. 54 +/- 3 and 37 +/- 3 vs. 16 +/- 3). Multivariate analysis indicated that CO and ipsilateral MAPo affected flow in both access types. In grafts, all three access resistance elements, AS, VS, and total independently influenced flow, whereas in AVF, the VS did not. Unexpectedly, the ratio of systemic to access resistance also influenced access flow. The pressure in the venous system draining the access affected access flow in AVF but not grafts. We conclude that the hemodynamics of grafts and AVF differ. Cardiac output, MAP, and the arterial segment resistance influence QA in both access types and need to be considered when evaluating QA as part of the trend analysis for detecting access dysfunction.

The effects of time elapsed after milking and lactation stage were assessed on the lactoperoxidase (LP) enzyme activity and concentrations of thiocyanate in Sahiwal cattle (N = 15) and Nili‐Ravi buffaloes (N = 15). The LP activity and thiocyanate concentrations decreased as the time elapsed after milking (P < 0.05) but the concentration of these components increased as the lactation advanced. The LP enzyme activity was sufficient until 12 h post milking but the thiocyanate concentration after 8 h decreased to an insufficient level to activate the LP System, hence additional thiocyanate would be beneficial from external sources. No difference was noted regarding the LPS activity in cattle and buffaloes at the time of collection and subsequently after storage. However, at the end of lactation, the thiocyanate concentration was lower in buffaloes than that in cattle. (P < 0.05).

Background: Bloodstream infections (BSIs) are an important frequent health problem in terms of their high incidence and lethal outcomes. The bacteria that frequently cause bacteremia are Staphylococcus, Streptococcus, Enterococcus, Escherichia coli, Klebsiella, Enterobacter, Pseudomonas, Neisseria and Haemophilus. Gram negative rods constitute a significant bulk in BSIs. The bloodstream infections due to multidrug resistant pathogens are on the rise globally making treatment more challenging. Aim: To identify the gram negative organisms causing blood stream infections and assess their susceptibility pattern so as to provide guidance for the empirical treatment hoping for better clinical outcome. Methodology: A retrospective, cross-sectional descriptive study carried out in Pathology Laboratory of Sharif City Hospital, Lahore. All the blood culture samples received in Microbiology laboratory between June 2017 to June 2019 were included in the study by non-probability consecutive sampling. Blood cultures were proceeded by subculturing on 1st and 5th day on MacConkey and Blood agar. The colonies obtained were identified through gram staining and biochemical profile. API20E was used for Enterobacteriaceae. Antibiotic susceptibility testing of the pathogens was by Kirby Bauer disc diffusion method. Results: In the current study 663 blood cultures were analyzed. Only 11.9% exhibited positive microbial growth. 55.7% of the positive cultures revealed gram negative bacteria. Among the pathogens isolated, E.coli was found to be responsible for BSIs in 22.7% cases, followed by Salmonella Typhi 20.4% and Klebsiella pneumoniae 18.1%.The gram negative rods exhibited a very high resistance for penicillins, cephalosporins and fluoroquinolones. The efficacy of aminoglycosides and results for carbapenems susceptibility were hopeful. Conclusion: The study shows that the Gram negative bacteria causing BSIs have shown unsatisfactory susceptibility to most of the commonly prescribed antimicrobials. The rising drug resistance has a major impact on the selection and prescription of antibiotics and calls for judicious use of antibiotics. Keywords: Gram Negative Organisms, Blood Culture, Antimicrobial Susceptibility Pattern

No abstract