In this report we describe the development of two rabbit strains, HAR (high atherosclerotic response) and LAR (low atherosclerotic response), and their propensities to develop atherosclerosis in the ...aorta despite similar levels of diet-induced hypercholesterolemia. Sixty-two randomly selected male New Zealand White rabbits were fed a cholesterol-enriched diet (0.5%) for 84 days and developed 57 plus/minus 25% sudanophilic lesions of the aortic surface; 12 rabbits showed a low atherosclerotic response (0% to 30% surface involvement), and 22 rabbits showed a high atherosclerotic response (70% to 100% surface involvement). The offspring of rabbits with low atherosclerotic response were used for breeding the strain of rabbits resistant to atherosclerosis (LAR strain), while the offspring of rabbits with high atherosclerotic response were used for breeding the HAR strain. Controlled breeding was started after the 4th generation and performed for the subsequent 6 generations. Thus, in the LAR rabbits the lipid-stainable surface area of aorta amounted to only 27 plus/minus 17% after 112 days of cholesterol feeding. On the other hand, in HAR rabbits, aortic surface involvement reached 85 plus/minus 25% after 112 days on the cholesterol-enriched diet. The measurements of surface area involvement were corroborated also by a significantly lower, chemically determined cholesterol content of the aorta in LAR rabbits. Plasma lipids and lipoproteins were determined at baseline, after 21 and 42 days of cholesterol feeding, and at the time the animals were killed. The plasma cholesterol concentrations of cholesterol-fed HAR and LAR rabbits showed a 13-fold increase after 21 days and a 21-fold increase after 84 days on the cholesterol diet. The development of hypercholesterolemia was similar in both rabbit strains. At the time the animals were killed, the plasma concentrations in the HAR and LAR rabbits were 1241 plus/minus 489 mg/dL and 1370 plus/minus 473 mg/dL, respectively. There was a comparable effect of cholesterol feeding on the plasma VLDL, IDL, and LDL levels, but no significant differences were observed in plasma HDL cholesterol levels. The degree of genetic diversity between the two rabbit strains was studied in inherited protein polymorphism of plasma and erythrocytes. The alleles of six protein markers segregated in both rabbit strains, with significant differences at the Es-1 and the Pgd loci. The outbred strain of LAR rabbits appears to represent a model of inherited resistance to the development of atherosclerosis. (Arterioscler Thromb Vasc Biol. 1995;15:1181-1188.)
The marked species differences in short-term toxicity (30-day LD50) of ca. 10,000 (LD50: guinea pigs ca. 1 microgram/kg body wt and Han/Wistar Kuopio rats more than 9600 micrograms/kg body wt) of ...2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is one of the central issues of the controversies that have developed on the validity of risk assessment strategies for TCDD and related compounds. One of the most challenging issues that toxicologists face today is the identification of genes that contribute to or are responsible for increased resistance or sensitivity to TCDD and related compounds. It is assumed that most, if not all, toxic effects of TCDD are mediated more or less through the binding affinity to the Ah receptor. This hypothesis was extended and tries to explain the differences in sensitivity/resistance of animals including humans to TCDD by their total fat (lipid) content. In this respect the gene or genes which is or are responsible for obesity of mammals including humans are of great interest. An obvious linear positive logarithmic relationship between the oral 30-day LD50 (microgram/kg) of TCDD in different species and strains of mammals and their total body fat content (TBF%) was found: log LD50 = 5.30 x log (TBF)-3.22, or LD50 = 0.000603 x (TBF)5.30. By means of this regression the toxicity of TCDD in mammals including humans of different age and/or body weight can be predicted if their total body fat content is known. Examples of single-gene and polygenic disease models in different mammals, such as nonobese diabetic, diabetic, viable yellow, obese, and fat mice, as well as transgenic mice, and other suitable animal models, such as fatty Zucker rats, Han/Wistar (Kuopio) rats, and minipigs, are discussed, and predicted LD50 values of TCDD in these animals and humans are presented.
The marked species differences in short-term toxicity (30-day LD50) of ca. 10,000 (LD50: guinea pigs ca. 1 μg/kg body wt and Han/Wistar Kuopio rats more than 9600 μg/kg body wt) of ...2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is one of the central issues of the controversies that have developed on the validity of risk assessment strategies for TCDD and related compounds. One of the most challenging issues that toxicologists face today is the identification of genes that contribute to or are responsible for increased resistance or sensitivity to TCDD and related compounds. It is assumed that most, if not all, toxic effects of TCDD are mediated more or less through the binding affinity to the Ah receptor. This hypothesis was extended and tries to explain the differences in sensitivity/resistance of animals including humans to TCDD by their total fat (lipid) content. In this respect the gene or genes which is or are responsible for obesity of mammals including humans are of great interest. An obvious linear positive logarithmic relationship between the oral 30-day LD50(μg/kg) of TCDD in different species and strains of mammals and their total body fat content (TBF%) was found: log LD50= 5.30 × log (TBF) − 3.22, or LD50= 0.000603 × (TBF)5.30. By means of this regression the toxicity of TCDD in mammals including humans of different age and/or body weight can be predicted if their total body fat content is known. Examples of single-gene and polygenic disease models in different mammals, such as nonobese diabetic, diabetic, viable yellow, obese, and fat mice, as well as transgenic mice, and other suitable animal models, such as fatty Zucker rats, Han/Wistar (Kuopio) rats, and minipigs, are discussed, and predicted LD50values of TCDD in these animals and humans are presented.
A new liver-specific rat carboxylesterase isozyme (EC 3.1.1.1) designated esterase-18 (ES-18) is described. Genetic variation of ES-18 was examined in 93 inbred strains and substrains and a ...structural locus Es-18 was suggested, coding for either the presence (Es-18a) or the absence (Es-18b) of the isozyme. Linkage studies involving two backcross series revealed that Es-18 resides in cluster 2 of LGV. No recombination between Es-18 and other cluster 2 loci was found in 19 lines of two RI strain sets or in the backcross series.
The segregation of rat esterases controlled by loci residing in linkage group V (LGV) has been studied in two backcross series, (LEW/Han X BN/Han)F1 X LEW/Han and (LEW/Han X LE/Han)F1 X LEW/Han. ...Es-14 (formerly Es-Si) was shown to be closely linked to Es-1. A new esterase locus, Es-15, was described which codes for a liver isozyme. The distribution pattern of three alleles at the Es-15 locus is presented for 52 independent inbred strains. Close linkage of Es-15 to Es-14 and to Es-1 was established, proposing the following gene order: Es-2, Es-10-ES-1, ES-14, ES-15. The esterase loci on LGV are thus separated into two gene clusters, cluster 1 and cluster 2. These conclusions are supported by the strain distribution patterns of the two RI strain series, LXB and DXE.
This study assessed the ability of mid-regional proadrenomedullin (MR-proADM) in comparison to conventional biomarkers (procalcitonin (PCT), lactate, C-reactive protein) and clinical scores to ...identify disease severity in patients with sepsis.
This is a secondary analysis of a randomised controlled trial in patients with severe sepsis or septic shock across 33 German intensive care units. The association between biomarkers and clinical scores with mortality was assessed by Cox regression analysis, area under the receiver operating characteristic and Kaplan-Meier curves. Patients were stratified into three severity groups (low, intermediate, high) for all biomarkers and scores based on cutoffs with either a 90% sensitivity or specificity.
1089 patients with a 28-day mortality rate of 26.9% were analysed. According to the Sepsis-3 definition, 41.2% and 58.8% fulfilled the criteria for sepsis and septic shock, with respective mortality rates of 20.0% and 32.1%. MR-proADM had the strongest association with mortality across all Sepsis-1 and Sepsis-3 subgroups and could facilitate a more accurate classification of low (e.g. MR-proADM vs. SOFA: N = 265 vs. 232; 9.8% vs. 13.8% mortality) and high (e.g. MR-proADM vs. SOFA: N = 161 vs. 155; 55.9% vs. 41.3% mortality) disease severity. Patients with decreasing PCT concentrations of either ≥ 20% (baseline to day 1) or ≥ 50% (baseline to day 4) but continuously high MR-proADM concentrations had a significantly increased mortality risk (HR (95% CI): 19.1 (8.0-45.9) and 43.1 (10.1-184.0)).
MR-proADM identifies disease severity and treatment response more accurately than established biomarkers and scores, adding additional information to facilitate rapid clinical decision-making and improve personalised sepsis treatment.
IMPORTANCE: High-dose intravenous administration of sodium selenite has been proposed to improve outcome in sepsis by attenuating oxidative stress. Procalcitonin-guided antimicrobial therapy may ...hasten the diagnosis of sepsis, but effect on outcome is unclear. OBJECTIVE: To determine whether high-dose intravenous sodium selenite treatment and procalcitonin-guided anti-infectious therapy in patients with severe sepsis affect mortality. DESIGN, SETTING, AND PARTICIPANTS: The Placebo-Controlled Trial of Sodium Selenite and Procalcitonin Guided Antimicrobial Therapy in Severe Sepsis (SISPCT), a multicenter, randomized, clinical, 2 × 2 factorial trial performed in 33 intensive care units in Germany, was conducted from November 6, 2009, to June 6, 2013, including a 90-day follow-up period. INTERVENTIONS: Patients were randomly assigned to receive an initial intravenous loading dose of sodium selenite, 1000 µg, followed by a continuous intravenous infusion of sodium selenite, 1000 µg, daily until discharge from the intensive care unit, but not longer than 21 days, or placebo. Patients also were randomized to receive anti-infectious therapy guided by a procalcitonin algorithm or without procalcitonin guidance. MAIN OUTCOMES AND MEASURES: The primary end point was 28-day mortality. Secondary outcomes included 90-day all-cause mortality, intervention-free days, antimicrobial costs, antimicrobial-free days, and secondary infections. RESULTS: Of 8174 eligible patients, 1089 patients (13.3%) with severe sepsis or septic shock were included in an intention-to-treat analysis comparing sodium selenite (543 patients 49.9%) with placebo (546 50.1%) and procalcitonin guidance (552 50.7%) vs no procalcitonin guidance (537 49.3%). The 28-day mortality rate was 28.3% (95% CI, 24.5%-32.3%) in the sodium selenite group and 25.5% (95% CI, 21.8%-29.4%) (P = .30) in the placebo group. There was no significant difference in 28-day mortality between patients assigned to procalcitonin guidance (25.6% 95% CI, 22.0%-29.5%) vs no procalcitonin guidance (28.2% 95% CI, 24.4%-32.2%) (P = .34). Procalcitonin guidance did not affect frequency of diagnostic or therapeutic procedures but did result in a 4.5% reduction of antimicrobial exposure. CONCLUSIONS AND RELEVANCE: Neither high-dose intravenous administration of sodium selenite nor anti-infectious therapy guided by a procalcitonin algorithm was associated with an improved outcome in patients with severe sepsis. These findings do not support administration of high-dose sodium selenite in these patients; the application of a procalcitonin-guided algorithm needs further evaluation. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00832039
IMPORTANCE: Adjunctive hydrocortisone therapy is suggested by the Surviving Sepsis Campaign in refractory septic shock only. The efficacy of hydrocortisone in patients with severe sepsis without ...shock remains controversial. OBJECTIVE: To determine whether hydrocortisone therapy in patients with severe sepsis prevents the development of septic shock. DESIGN, SETTING, AND PARTICIPANTS: Double-blind, randomized clinical trial conducted from January 13, 2009, to August 27, 2013, with a follow-up of 180 days until February 23, 2014. The trial was performed in 34 intermediate or intensive care units of university and community hospitals in Germany, and it included 380 adult patients with severe sepsis who were not in septic shock. INTERVENTIONS: Patients were randomly allocated 1:1 either to receive a continuous infusion of 200 mg of hydrocortisone for 5 days followed by dose tapering until day 11 (n = 190) or to receive placebo (n = 190). MAIN OUTCOMES AND MEASURES: The primary outcome was development of septic shock within 14 days. Secondary outcomes were time until septic shock, mortality in the intensive care unit or hospital, survival up to 180 days, and assessment of secondary infections, weaning failure, muscle weakness, and hyperglycemia (blood glucose level >150 mg/dL to convert to millimoles per liter, multiply by 0.0555). RESULTS: The intention-to-treat population consisted of 353 patients (64.9% male; mean SD age, 65.0 14.4 years). Septic shock occurred in 36 of 170 patients (21.2%) in the hydrocortisone group and 39 of 170 patients (22.9%) in the placebo group (difference, −1.8%; 95% CI, −10.7% to 7.2%; P = .70). No significant differences were observed between the hydrocortisone and placebo groups for time until septic shock; mortality in the intensive care unit or in the hospital; or mortality at 28 days (15 of 171 patients 8.8% vs 14 of 170 patients 8.2%, respectively; difference, 0.5%; 95% CI, −5.6% to 6.7%; P = .86), 90 days (34 of 171 patients 19.9% vs 28 of 168 patients 16.7%; difference, 3.2%; 95% CI, −5.1% to 11.4%; P = .44), and 180 days (45 of 168 patients 26.8% vs 37 of 167 patients 22.2%, respectively; difference, 4.6%; 95% CI, −4.6% to 13.7%; P = .32). In the hydrocortisone vs placebo groups, 21.5% vs 16.9% had secondary infections, 8.6% vs 8.5% had weaning failure, 30.7% vs 23.8% had muscle weakness, and 90.9% vs 81.5% had hyperglycemia. CONCLUSIONS AND RELEVANCE: Among adults with severe sepsis not in septic shock, use of hydrocortisone compared with placebo did not reduce the risk of septic shock within 14 days. These findings do not support the use of hydrocortisone in these patients. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00670254
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