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Purpose: Lactate thresholds are physiological parameters used to train athletes and monitor performance or training. Currently, the assessment of lactate thresholds in kayakers is performed in a laboratory setting utilizing specific ergometers; however, laboratory tests differ from on-water evaluation for several reasons. The aim of this study was to assess reliability and validity of a new on-water incremental test for the assessment of blood lactate response to exercise in flat-water kayakers. Maximal lactate steady state test (MLSS) was used as criterion measurement., Methods: Eleven junior (16.5 ± 1.9 yr) élite flat-water kayakers performed: i) an incremental cardiopulmonary test up to voluntary exhaustion on a stationary kayak ergometer to determine peak oxygen uptake; ii) an on-water 1000-m distance trial (T1000) to record best performance time and average speed (S1000); iii) two repetitions of on-water incremental kayaking test (WIK test); iv) several repetitions of on-water constant speed tests to determine MLSS. Speed, HR, and blood lactate concentrations were determined during on-water tests., Results: The best performance time in T1000 was 262 ± 13 s, corresponding to an S1000 of 3.82 ± 0.19 m·s. Lactate threshold determined by modified Dmax method (LTDmod) during WIK test was 2.78 ± 1.02 mmol·L and the corresponding speed (SLT) was 3.34 ± 0.16 m·s. Test-retest reliability, calculated on SLT, was strong (ICC = 0.95 and r = 0.93). MLSS test corresponded to 3.06 ± 0.68 mmol·L and was reached at a speed (SMLSS) of 3.36 ± 0.14 m·s. Correlation coefficient between SLT and SMLSS was 0.90 (P = 0.0001). Interestingly, a significant correlation (r = 0.96, P < 0.0001) was observed between SLT and S1000., Conclusions: The WIK test showed good reliability and validity for the assessment of speed corresponding to LTDmod in flat-water kayakers and it could be a useful tool to monitor athletic performance. The speed value at LTDmod nicely predicted performance on 1000 m.

Objective: To investigate the efficacy of buforin II and rifampin in an experimental rat model of Acinetobacter baumannii sepsis., Design: Prospective, randomized, controlled animal study., Setting: Research laboratory in a university hospital., Subjects: Adult male Wistar rats., Interventions: The animals received intraperitoneally 1 mL saline containing 2 x 10 colony forming units of A. baumannii ATCC 19606 (model i) or the multiresistant strain (model ii). Immediately after bacterial challenge, animals received intravenously a single dose of isotonic sodium chloride solution (control groups C1 and C2), 1 mg/kg of buforin II, 10 mg/kg of rifampin, and 1 mg/kg of buforin II plus 10 mg/kg of rifampin, respectively., Measurements and Main Results: Lethality, bacterial growth in blood and tissue burden, endotoxin, interleukin-6, and tumor necrosis factor-alpha concentrations in plasma. Buforin II showed good antimicrobial activity and achieved a significant reduction of plasma endotoxin and cytokines concentration when compared with control and rifampin-treated groups. Combination among buforin II proved to be the most effective treatment in reducing all variables measured., Conclusion: In an experimental model, buforin II and rifampin might have a potential role in the treatment of severe infections due to A. baumannii.

A promising therapeutic strategy for the management of severe Pseudomonas infection in neutropenic patients may result from the coadministration of colony-stimulating factors (CSFs) that help maintain immune competence and antimicrobial peptides, a novel generation of adjunctive therapeutic agents with antimicrobial and anti-inflammatory properties. A promising peptide with these properties is LL-37, the only member of the cathelicidin family of antimicrobial peptides found in humans. BALB/c male mice were rendered neutropenic by intraperitoneal administration of cyclophosphamide on days -4 and -2 preinfection. Septic shock was induced at time 0 by intraperitoneal injection of 2x10 colony-forming units of P. aeruginosa American Type Culture Collection (ATCC) 27853. All animals were randomized to receive intravenously isotonic sodium chloride solution, 1 mg/kg of LL-37, 20 mg/kg of imipenem, 0.1 mg/kg of granulocyte CSF (G-CSF), 1 mg/kg of LL-37+0.1 mg/kg of G-CSF, or 20 mg/kg of imipenem+0.1 mg/kg of G-CSF. Lethality and bacterial growth in blood, peritoneum, spleen, liver, and kidney were evaluated. All regimens were significantly superior to controls at reducing the mouse lethality rate and bacterial burden in organs. Particularly, the combination between LL-37 and G-CSF was the most effective in protecting neutropenic mice from the onset of sepsis and in vitro significantly reduced the apoptosis of neutrophils. Combination therapy between LL-37 and G-CSF is a promising therapeutic strategy for the management of severe Pseudomonas infection complicated by neutropenia.

Objective: To investigate the efficacy of piperacillin/tazobactam combined with indolicidin in the prevention of lethality in two rat models of polymicrobial peritonitis., Design: Prospective, randomized, controlled animal study., Setting: Research laboratory in a university hospital., Subjects: Adult male Wistar rats., Interventions: Adult male Wistar rats were given an intraperitoneal injection of 1 mg of Escherichia coli 0111:B4 lipopolysaccharide or had intraabdominal sepsis induced by cecal ligation and puncture. For each model, all animals were randomized to receive isotonic sodium chloride solution intraperitoneally, 1 mg/kg indolicidin, 120 mg/kg piperacillin/tazobactam, and 1 mg/kg indolicidin combined with 120 mg/kg piperacillin/tazobactam. Each group included 20 animals., Measurements and Main Results: Main outcome measures were: bacterial growth in blood, peritoneum, spleen, liver, and mesenteric lymph nodes; endotoxin, interleukin-6, and tumor necrosis factor-alpha concentrations in plasma; and lethality. All compounds reduced significantly bacterial growth and lethality compared with saline treatment. Treatment with indolicidin resulted in significant decrease in plasma endotoxin and cytokine levels, whereas piperacillin/tazobactam exerted the opposite effect. The combination between indolicidin and piperacillin/tazobactam proved to be the most effective treatment in reducing all variables measured., Conclusion: Indolicidin may have potential therapeutic usefulness alone and when associated with piperacillin/tazobactam in polymicrobial peritonitis.

A mouse model of staphylococcal sepsis was used to evaluate the efficacy of RNAIII-inhibiting peptide (RIP) combined with the cathelicidin BMAP-28. Preliminary in vitro studies showed that both peptides, alone or combined, were able to inhibit the lipoteichoic acid-induced production of tumor necrosis factor alpha and nitric oxide by RAW 264.7 cells. For in vivo experiments, the main outcome measures were lethality, quantitative blood cultures, and detection of tumor necrosis factor alpha and interleukin 6 plasma levels. BALB/c mice were injected i.v. with 2.0 x 10(6) colony-forming units of live Staphylococcus aureus ATCC 25923 or with 5.0 x 10(8) heat-killed cells of the same strain. All animals were randomized to receive i.v. isotonic sodium chloride solution, 10-mg/kg RIP, alone or in combination with 2-mg/kg BMAP-28, 7-mg/kg imipenem, or 7-mg/kg vancomycin, immediately and at 6 hours after bacterial challenge. In in vivo experiments performed with live bacteria, all compounds reduced lethality rates and bacteremia when compared with controls. In general, combined-treated groups had significantly lower bacteremia when compared with single-treated groups. Lowest lethality rates and bacteremia were obtained when RIP was administered in combination with BMAP-28 or vancomycin. In the experiments performed using heat-killed organisms, only BMAP-28 demonstrated significant efficacy on lethality rates and cytokines plasma levels when compared with controls. RIP combined with BMAP-28 exhibited the highest efficacy on all main outcome measurements. These data were observed on both immediate and delayed treatments. These results highlight the capacity of RIP and BMAP-28 to reduce the septic effects of bacterial cell components and exotoxins, and suggest their potential use in the treatment of severe staphylococcus-associated sepsis.

Sepsis remains a serious clinical problem despite intense efforts to improve survival. In this study, the efficacy of ertapenem combined with the cathelicidin tritrpticin was investigated in two rat models of septic shock. Main outcome measures were bacterial growth in blood, peritoneum, spleen, liver, and mesenteric lymph nodes; endotoxin, interleukin 6, and tumor necrosis factor alpha concentrations in plasma; and lethality. Adult male Wistar rats were given (1) an intraperitoneal injection of 1 mg Escherichia coli serotype 0111:B4 LPS or (2) intra-abdominal sepsis induced via cecal ligation and puncture. For each model, all animals were randomized to receive intraperitoneally isotonic sodium chloride solution, 1 mg/kg tritrpticin, 15 mg/kg ertapenem, and 1 mg/kg tritrpticin combined with 15 mg/kg ertapenem. Each group included 20 animals. All compounds significantly reduced bacterial growth and lethality as compared with saline treatment. Treatment with tritrpticin resulted in significant decrease in plasma endotoxin and cytokine levels, whereas ertapenem exerted opposite effect. The combination between tritrpticin and ertapenem proved to be the most effective treatment in reducing all variables measured. In conclusion, tritrpticin enhances ertapenem efficacy in gram-negative septic shock rat models.

Objective: A mouse model of staphylococcal sepsis was used to compare the efficacy of the bovine antimicrobial peptide BMAP-28, a compound of the cathelicidin family, with that of conventional antibiotics., Design: Prospective, randomized, controlled animal study., Setting: Research laboratory in a university hospital., Subjects: BALB/c male mice., Interventions: BALB/c mice were injected intravenously with 2.0 x 10(6) colony-forming units of live Staphylococcus aureus ATCC 25923 or with 5.0 x 10(8) heat-killed cells of the same strain. All animals were randomized to receive intravenously isotonic sodium chloride solution, 2 mg/kg BMAP-28, 7 mg/kg imipenem, 7 mg/kg vancomycin, 7 mg/kg clindamycin, and 7 mg/kg clarithromycin immediately and at 6 hrs after bacterial challenge., Measurements and Main Results: Lethality, quantitative blood cultures, and detection of tumor necrosis factor-alpha and interleukin-6 plasma levels. In the experiments performed with live bacteria, all compounds reduced lethality rates and bacterial growth compared with controls. Imipenem and vancomycin exhibited the highest efficacy on these main outcome measures. In the experiments performed using heat-killed organisms, only BMAP-28 demonstrated significant efficacy on lethality rates, tumor necrosis factor-alpha, and interleukin-6 plasma levels compared with controls., Conclusion: These results highlight the capacity of BMAP-28 to reduce the effects of components of the bacterial cells and suggest that it may be beneficial in the treatment of severe staphylococcal infections in concert with other antimicrobial agents.

Objective: To investigate the efficacy of imipenem, piperacillin combined with cecropin B in the prevention of lethality in 2 rat models of septic shock. Main outcome measures were bacterial growth in blood and intra-abdominal fluid, endotoxin and TNF-alpha concentrations in plasma, and lethality., Background: Sepsis remains a serious clinical problem despite intense efforts to improve survival. It is a major cause of morbidity and mortality in hospitalized patients. The primary cause of Gram-negative shock results from activation of host effector cells by endotoxin, the lipopolysaccharide (LPS) associated with cell membranes of Gram-negative bacteria., Methods: Adult male Wistar rats were given (1). an intraperitoneal injection of 1 mg of Escherichia coli 0111:B4 LPS or (2). 2 x 1010 CFU of E. coli ATCC 25922. All animals were randomized to receive intraperitoneally isotonic sodium chloride solution, 1 mg/kg cecropin B, 20 mg/kg imipenem, and 120 mg/kg piperacillin alone and combined with 1 mg/kg cecropin B. Each group included 20 animals. RESULTS All compounds reduced the lethality when compared with controls. Piperacillin and imipenem significantly reduced the lethality and the number of E. coli in abdominal fluid compared with saline treatment. On the other hand, each betalactam determined an increase of plasma endotoxin and TNF-alpha concentration. Combination between cecropin B and betalactams showed to be the most effective treatment in reducing all variables measured., Conclusion: Cecropin B enhances betalactams activities in Gram-negative sepic shock rat models.

Background: Bacteria that adhere to implanted medical devices play an important role in industry and in modern medicine. Staphylococci are among the most common pathogens that cause biomaterial infections. Vascular prosthetic graft infection is one of the most feared complications that the vascular surgeon treats, frequently resulting in prolonged hospitalization, organ failure, amputation, and death. A rat model was used to investigate the topical efficacies of temporin A and the quorum-sensing inhibitor RNAIII-inhibiting protein (RIP) as prophylactic agents of vascular prosthetic graft infections caused by Staphylococcus aureus and Staphylococcus epidermidis with intermediate resistance to glycopeptides., Methods and Results: Graft infections were established in the back subcutaneous tissue of adult male Wistar rats by implantation of Dacron prostheses 1 cm2 followed by topical inoculation with 2x10(7) colony-forming units of bacterial strains. The study included, for each staphylococcal strain, a control group (no graft contamination), a contaminated group that did not receive antibiotic prophylaxis, and 6 contaminated groups that received grafts soaked with temporin A, RIP, rifampin, temporin A plus RIP, RIP plus rifampin, or temporin A plus RIP. The infection was evaluated by quantitative agar culture. When tested alone, temporin A and RIP showed comparable efficacies, and their efficacies were significantly higher than that of rifampin against both strains. All combinations showed efficacies significantly higher than that of each single compound. The combinations of temporin A and RIP exerted the strongest antistaphylococcal efficacies, eliminating infection by 100%., Conclusions: The results of the present study make these molecules potentially useful for antimicrobial chemoprophylaxis in vascular surgery.

Lipopolysaccharides (LPS), or endotoxins, are structural components of gram-negative bacteria implicated in the pathogenesis of septic shock. In this study the antiendotoxin activity of Bac7(1-35), a synthetic peptide based on the sequence of a proline-rich antibacterial peptide from bovine neutrophils, was investigated in vitro and in an experimental rat model of gram-negative septic shock. The ability of Bac7(1-35) to bind LPS from Escherichia coli O111:B4 was determined using a sensitive Limulus chromogenic assay. In the in vivo study, adult male Wistar rats were given an intraperitoneal injection of 1 x 10(9) colony-forming units of E. coli ATCC 25922. All animals were randomized to receive intraperitoneally 1 mg/kg Bac7(1-35), or isotonic sodium chloride solution (control group C1), 60 mg/kg of piperacillin and 1 mg/kg polymyxin B, 1 mg/kg of polymyxin B plus 60 mg/kg of piperacillin, and 1 mg/kg of Bac7(1-35) plus 60 mg/kg of piperacillin. Each group included 15 animals. Bac7(1-35) was found to completely inhibit the LPS procoagulant activity at approximately 10 microM peptide concentration, as determined by in vitro LAL chromogenic assay. Treatment with Bac7(1-35) resulted in significant decrease in plasma endotoxin levels and lethality rates compared with saline injected control animals. No statistically significant differences were noted between Bac7(1-35) and polymyxin B in reducing all variables measured. These results provide evidence for the ability of Bac7(1-35) to effectively bind LPS and protect animals from lethal effects of this molecule, and point to its potential use for the treatment of endotoxin-induced septic shock.

Objectives: To compare the response to highly active antiretroviral therapy (HAART) in individuals starting HAART at different CD4 cell counts., Design: The mean increase in CD4 cell count and rate of virological failure after commencing HAART were measured in antiretroviral-naive patients (1421) in a large, non-randomized multicentre, observational study in Italy (ICONA). Clinical endpoints were also evaluated in a subset of patients who started HAART with a very low CD4 cell count., Results: After 96 weeks of therapy, the mean rise in CD4 cell count was 280, 281 and 186 x 10(6) cells/l in patients starting HAART with a CD4 cell count < 200, 201--350 and > 350 x 10(6) cells/l, respectively. Patients starting HAART with a CD4 cell count < 200 x 10(6) cells/l tended to have a higher risk of subsequent virological failure [relative hazard (RH), 1.15; 95% confidence interval (CI), 0.93--1.42] compared with patients starting with > 350 x 10(6) cells/l. There was no difference in risk between the 201--350 and the > 350 x 10(6) cells/l groups (RH, 1.0; 95% CI, 0.79--1.29). The incidence of new AIDS-defining diseases/death in patients who started HAART with a CD4 count < 50 was 0.03/person-year (95% CI, 0.10--0.33) during the time in which the patient's CD4 cell count had been raised to > 200 x 10(6) cells/l., Conclusions: There was no clear immunological or virological advantage in starting HAART at a CD4 cell count > 350 rather than at 200--350 x 10(6) cells/l. The increase in CD4 cells restored by HAART is meaningful in that they are associated with reduced risk of disease/death.

Although the efficacy of switching from zidovudine (AZT) to didanosine (ddI) has already been evaluated in controlled studies, prior investigations were not specifically designed to evaluate this issue in patients with acquired immune deficiency syndrome (AIDS). This open, randomized, multicenter study (ISS 901) was designed to evaluate the clinical benefit in patients with AIDS of switching to ddI after 6-18 months of AZT and no major intolerance. Patients were randomized to continue AZT, maintaining the current dosage at randomization (n = 79), or to receive ddI (n = 80) at the dosage of 375 mg and 250 mg b.i.d. for body weight > 60 and < or = 60 kg, respectively. Primary efficacy measures were survival and time to new AIDS-defining events, analyzed by the intent-to-treat approach. The two groups were comparable for baseline characteristics, follow-up (15 months), and time spent on allocated treatment. At the end of the study, 104 patients (48 AZT, 56 ddI) had died and 90 had at least one new AIDS-defining event (44 AZT, 46 ddI). Kaplan-Meier estimates of survival and of time to first new AIDS-defining event showed no differences between the treatment groups. No differences were detected in other efficacy measurements (p24 antigenemia, CD4+ count, Karnofsky score, and body weight), occurrence of severe toxicities, and treatment modifications. Pancreatitis occurred only in ddI-treated patients (6%). In our population of patients with advanced disease, switching from AZT to ddI did not produce apparent benefits, suggesting that application of this strategy earlier in the course of human immunodeficiency virus disease should be considered.