分光光度法检测血清百草枯质量浓度及意义

目的 评价分光光度法测定血清百草枯(paraquat,PQ)质量浓度的可靠性及其临床意义。方法 验证普通分光光度法和二阶导数分光光度法测定血清PQ质量浓度的检测波长后,采用二阶导数分光光度法测定血清PQ质量浓度,确定其线性范围并评价其准确性;采用该法测定8例PQ中毒患者血清PQ质量浓度并与高效液相色谱法测定值比较分析其可靠性;对上海市第十人民医院肾病免疫科2008年10月至2010年9月收治的口服PQ4h以上人院的21例急性PQ中毒患者的资料行回顾性统计分析,根据该法测定患者入院时血清PQ质量浓度是否大于1.8 μ.g/mL分为两组,采用成组t检验和Fisher精确概率法对两组患者的临床特征进行统计分析。结果 (1)普通分光光度法检测含PQ血清样本时在257 nm波长处未见明显吸收峰;(2)二阶导数分光光度法测定血清PQ质量浓度在0.4～8.0 μg/mL范围内呈现良好的线性关系,相关系数为0.996;回收率为95.0％～99.5％,相对标准差(RSD)为1.35％～5.41％ (n=6),检出下限为0.05 μg/mL;(3)8例PQ中毒患者血清PQ质量浓度二阶导数分光光度法测定值与HPLC法检测值相吻合,r=0.995,P＜0.01;(4)血清PQ质量浓度＞1.8 μg/mL组患者存活率为22.2％,酸中毒和少尿发生率55.6％,纵膈气肿发生率77.8％,与血清PQ质量浓度＜1.8 μg/mL组比较差异均有统计学意义(P＜0.05)。结论 (1)普通分光光度法用于测定血清PQ质量浓度不能采用257 rn为检测波长;(2)二阶导数分光光度法用于检测血清百草枯质量浓度可靠性高;(3)二阶导数分光光度法测定值可用于中毒患者的临床严重程度判断,口服PQ中毒4h后血清质量浓度＞1.8 μg/mL是患者预后不良的重要指标。     

Effect of SP-A/B in lipoic acid on acute paraquat poisoning

BACKGROUND:

This study was undertaken to observe the concentration of SP-A/B and the pulmonary surfactant in the lung tissue of rats with acute lung injury/acute respiratory distress syndrome caused by paraquat poisoning after the treatment of metabolic antioxidant-lipoic acid and whether its influence was related to TNF-α.

METHODS:

Sixty-six male Sprage-Dawley rats were randomly divided into three groups: normal control group (NS group), 6 rats; paraquat poisoning group (PQ group), 30 rats; and paraquat+lipoic acid treatment group (LA group), 30 rats. The rats in the PQ and LA groups were subdivided into 3-, 6-, 12-, 24-, 48-hour subgroups, with 6 rats in each group. After the rats were sacrificed, lung tissue from the same part was taken from the rats. After HE staining, histological changes were observed in the tissue under a light microscope. Lung tissue was also taken to test the levels of superoxide dismutase (SOD) and malondialdehyde (MDA). Whole blood (0.8 mL) without anticoagulant was drawn from the tail vein of rats for the determination of the TNF-α level. The total RNA of the lung tissue was collected, and the Rt-PCR method was used to measure the levels of SP-A and SP-B mRNA.

RESULTS:

HE staining showed that histopathological changes were milder in the LA group than in the PQ group. There were significant differences in MDA and SOD levels between different intervals both in intergroups and intragroups except the 3-hour subgroup (P<0.01). Likewise, the significant differences in the levels of TNF-α were also present between the three groups and between different intervals (P<0.01). The significant differences in SP-A mRNA and SP-B mRNA amplification ratio were seen between the three groups at the same intervals (P<0.01), but the differences between different intervals in the PQ group were statistically significant (P<0.05). The differences between different intervals in the LA group were statistically significant (P<0.01).

CONCLUSION:

Lipoic acid in acute paraquat poisoning could diminish lung tissue damage by regulating directly tumor necrosis factor and indirectly the content of pulmonary surfactant so as to reduce pulmonary edema, improve lung compliance, and finally protect lung tissues.KEYWORDS: Lipoic acid, Paraquat, Acute lung injury, Surfactant protein, Tumor necrosis factor-α, Oxygen free radical, Superoxide dimutase, Malonaldehyde     

Therapeutic effects of smecta or smectite powder on rats with paraquat toxication

BACKGROUND:

The plasma concentration of paraquat is closely related to the prognosis of patients with paraquat toxication, and the most common cause of death from paraquat poisoning is multiple organ failure (MOF). This study aimed to evaluate therapeutic effect of smecta on the plasma concentrations of paraquat and multi-organ injury induced by paraquat intoxication in rats.

METHODS:

A total of 76 healthy adult SD rats were randomly divided into group A (control group, n=6), group B (poisoned group, n=30) and group C (smecta-treated group, n=30). Rats in groups B and C were treated intragastrically with PQ at 50 mg/kg, and rats in group A was treated intragastrically with saline (1 mL). Rats in group C were given intragastrically smecta at 400 mg/kg 10 minutes after administration of PQ, while rats in other two groups were treated intragastrically with 1 mL saline at the same time. Live rats in groups B and C were sacrificed at 2, 6, 24, 48, 72 hours after administration of PQ for the determination of paraquat plasma concentrations and for HE staining of the lung, stomach and jejunum. The rats were executed at the end of trial by the same way in group A.

RESULTS:

The plasma concentration of paraquat (ng/mL) ranged from 440.314±49.776 to 4320.6150±413.947. Distinctive pathological changes were seen in the lung, stomach and jejunum in group B. Lung injuries deteriorated gradually, edema, leukocyte infiltration, pneumorrhagia, incrassated septa and lung consolidation were observed. Abruption of mucosa, hyperemic gastric mucosa and leukocyte infiltration were obvious in the stomach. The hemorrhage of jejunum mucosa, the abruption of villus, the gland damage with the addition of inflammatory cell infiltration were found. Compared to group B, the plasma concentration of paraquat reduced (P<0.01) and the pathological changes mentioned above were obviously alleviated in group C (P<0.05, P<0.01).

CONCLUSION:

Smecta reduced the plasma concentration of paraquat and alleviated pathologic injury of rats with PQ poisoning.KEY WORDS: Smecta, Paraquat, Pathological change, Therapeutic injury     

Imaging in detecting sites of pulmonary fibrosis induced by paraquat

BACKGROUND:

The most common cause of death from paraquat (PQ) poisoning is respiratory failure from pulmonary fibrosis, which develops through pathological overproduction of extracellular matrix proteins such as collagens. In this study, a MicroCT system was used to observe dynamic changes of pulmonary fibrosis in rats with PQ poisoning, and find the characteristics of interstitial lung diseases via density-based and texture-based analysis of CT images of the lung structure.

METHODS:

A total of 15 male SD rats were randomly divided into a control group (n=5) and a PQ poisoning group (n=10). The rats in the poisoning group were intraperitoneally administered with 4 mg/ mL PQ at 14 mg/kg, and the rats in the control group were administered with the same volume of saline. The signs of pulmonary fibrosis observed by the MicroCT included ground-glass opacity, nodular pattern, subpleural interstitial thickening, consolidation honeycomb-like shadow of the lung.

RESULTS:

Compared with the control group, the rats with acute PQ poisoning had different signs of pulmonary fibrosis. Ground-glass opacity and consolidation of the lung appeared at the early phase of pulmonary fibrosis, and subpleural interstitial thickening and honeycomb-like shadow developed at the middle or later stage. MicroCT images showed that fibrotic lung tissues were denser than normal lungs, and their density was up-regulated with pulmonary fibrosis. There was no difference in the progress of pulmonary fibrosis between the right lung and the left lung (P>0.05), but there were differences in fibrosis degree at different sites in the lung (P<0.05 or P<0.01). Pulmonary fibrosis was mainly seen in the exterior area of the middle-lower part of the lung.

CONCLUSION:

Imaging can show the development of pulmonary fibrosis in PQ poisoning rats, and this method may help to administer drugs more reasonably in treating pulmonary fibrosis.KEY WORDS: MicroCT, CT value, Paraquat, Pulmonary fibrosis, Region of interest     

Insufficient β-lactam concentrations in the early phase of severe sepsis and septic shock

Introduction

Altered pharmacokinetics (PK) in critically ill patients can result in insufficient serum β-lactam concentrations when standard dosages are administered. Previous studies on β-lactam PK have generally excluded the most severely ill patients, or were conducted during the steady-state period of treatment. The aim of our study was to determine whether the first dose of piperacillin-tazobactam, ceftazidime, cefepime, and meropenem would result in adequate serum drug concentrations in patients with severe sepsis and septic shock.

Methods

Open, prospective, multicenter study in four Belgian intensive care units. All consecutive patients with a diagnosis of severe sepsis or septic shock, in whom treatment with the study drugs was indicated, were included. Serum concentrations of the antibiotics were determined by high-pressure liquid chromatography (HPLC) before and 1, 1.5, 4.5 and 6 or 8 hours after administration.

Results

80 patients were treated with piperacillin-tazobactam (n = 27), ceftazidime (n = 18), cefepime (n = 19) or meropenem (n = 16). Serum concentrations remained above 4 times the minimal inhibitory concentration (T > 4 × MIC), corresponding to the clinical breakpoint for Pseudomonas aeruginosa defined by the European Committee on Antimicrobial Susceptibility Testing (EUCAST), for 57% of the dosage interval for meropenem (target MIC = 8 μg/mL), 45% for ceftazidime (MIC = 32 μg/mL), 34% for cefepime (MIC = 32 μg/mL), and 33% for piperacillin-tazobactam (MIC = 64 μg/mL). The number of patients who attained the target PK profile was 12/16 for meropenem (75%), 5/18 for ceftazidime (28%), 3/19 (16%) for cefepime, and 12/27 (44%) for piperacillin-tazobactam.

Conclusions

Serum concentrations of the antibiotic after the first dose were acceptable only for meropenem. Standard dosage regimens for piperacillin-tazobactam, ceftazidime and cefepime may, therefore, be insufficient to empirically cover less susceptible pathogens in the early phase of severe sepsis and septic shock.     

Prospective experimental studies on the renal protective effect of ulinastatin after paraquat poisoning

BACKGROUND:

Paraquat (PQ) is an effective herbicide and is widely used in agricultural production, but PQ poisoning is frequently seen in humans with the lung as the target organ. Currently, there are many studies on lung injury after PQ poisoning. But the kidney as the main excretory organ after PQ poisoning is rarely studied and the mechanisms of this poisoning is not very clear. In this study, we observed the expression of caspase-3 and livin protein in rat renal tissue after PQ poisoning as well as the therapeutic effects of ulinastatin.

METHODS:

Fifty-four Sprague-Dawley (SD) rats were randomly divided into three experimental groups: control group (group A), paraquat poisoning group (group B) and ulinastatin group (group C), with 18 rats in each group. Rats in group B and group C were administered intragastrically with 80 mg/kg PQ, rats in group C were injected peritoneally with 100 000 U/kg ulinastatin once a day, while rats in group A were administered intragastrically with the same volume of saline as PQ. At 24, 48, 72 hours after poisoning, the expression of livin in renal tissue was detected by Westen blotting, the expression of caspase-3 was detected by immunohistochemistry, and the rate of renal cell apoptosis was tested by TUNEL detection. The histopathological changes were observed at the same time.

RESULTS:

Compared to group A, the expression of caspase-3 in the renal tissue of rats in groups B and C increased significantly at any time point. Compared with group B, the expression of caspase-3 in renal tissue of rats in group C decreased. Compared with group A, the expression of livin in renal tissue in rats of groups B and C increased significantly at any time point (P<0.01), especially in group C (P<0.01). TUNEL method showed that the rate of renal cell apoptosis index was higher in group B at corresponding time points than in group A (P<0.01), and was lower in group C at corresponding time points than in group B (P<0.01).

CONCLUSION:

UTI has a protective effect on the renal tissue of rats after paraquat poisoning through up-regulating the expression of livin and down-regulating the expression of caspase-3, but the regulation path still needs a further research.KEY WORDS: Paraquat, Ulinastatin, Renal, Apoptosis, Livin, Caspase-3     

Expression of heat shock protein 70 in lung tissues of acute paraquat poisoned rats and intervention of ulinastatin

BACKGROUND:

Paraquat (PQ) is an effective herbicide and is widely used in agricultural production, but PQ poisoning is frequently seen in humans with the lung as the target organ. Clinically pulmonary pathological changes are often used to predict the severity and prognosis of the patients. In this study, we observed the expression of heat shock protein 70 (HSP70) in rat lung after PQ poisoning and to investigate the therapeutic effects of ulinastatin.

METHODS:

Seventy-two adult healthy SD rats were randomly divided into a control group (group A, n=24), a poisoning group (group B, n=24), and an ulinastatin group (group C, n=24). The rat models of acute PQ poisoning were established by intra-gastric administration of 80 mg/kg PQ to rats of groups B and C, and the rats of group C were intra-peritoneally injected with 100 000 IU/kg ulinastatin 30 minutes after poisoning. The expression of HSP70 in lung tissue was observed, and W/D and histopathological changes in the lung tissue were compared 12, 24, 48 and 72 hours after poisoning. The expression of HSP70 in the lung tissue was assayed by using RT-PCR. All quantitative data were processed with one-way analysis of variance to compare multiple sample means.

RESULTS:

Compared to group A, the expression of HSP70 in the lung of rats in groups B and C increased significantly at all intervals (P<0.05). The pathological changes in lung tissue of rats with PQ poisoning included congestion, leukocytes infiltration and local hemorrhage, whereas those of group C were significantly lessened.

CONCLUSION:

Ulinastatin may ameliorate acute lung injury to some extent after PQ poisoning in rats by enhancing the expression of HSP70.KEY WORDS: Paraquat, Poisoning, Ulilnastatin, Heat shock protein, Acute lung injury     

Reevaluation of Kanamycin Dosage in Infants and Children

It was recently reported that the dosage of kanamycin formerly recommended for neonates of 7.5 mg/kg every 12 h did not produce therapeutic serum concentrations of 15 to 25 μg/ml, but a larger dosage of 10 mg/kg every 12 h was required. Reevaluation of the pharmacokinetics of kanamycin in infants and children was therefore undertaken. Sixteen time-concentration curves after a dose of 5 mg/kg were obtained from patients 2 months to 12 years of age; the mean peak serum kanamycin concentration was 10.9 (range, 3.6 to 17.9) μg/ml at 0.5 h. Ten time-concentration curves were obtained after a dose of 10 mg/kg; the mean peak serum concentration was 17.6 (range, 8.4 to 30) μg/ml. Eight patients were studied on successive days, and there was doubling of the 1-h peak serum concentration when the dose of kanamycin was increased from 5 to 10 mg/kg. Standard serum bactericidal tests were done against Escherichia coli and Enterobacter cloacae strains, each with a minimal bactericidal concentration of 5 μg of kanamycin per ml. All 3 sera containing 21 μg or more of kanamycin per ml demonstrated a bactericidal titer, whereas only 2 of 23 sera containing less than 21 μg of kanamycin per ml did so. The currently recommended dosage of kanamycin for infants and children fails to produce serum concentrations in the therapeutic range, and preliminary data suggest that the dosage should be increased to 10 mg/kg per dose every 8 h.     

Population Pharmacokinetics,Tolerability, and Safety of Dihydroartemisinin-Piperaquine and Sulfadoxine-Pyrimethamine-Piperaquine in Pregnant and Nonpregnant Papua New Guinean Women

The tolerability, safety, and disposition of dihydroartemisinin (DHA) and piperaquine (PQ) were assessed in 32 pregnant (second/third trimester) and 33 nonpregnant Papua New Guinean women randomized to adult treatment courses of DHA-PQ (three daily doses) or sulfadoxine-pyrimethamine (SP)-PQ (three daily PQ doses, single dose of SP). All dose adminstrations were observed, and subjects fasted for 2 h postdose. Plasma PQ was assayed by using high-performance liquid chromatography, and DHA was assessed by using liquid chromatography-mass spectrometry. Compartmental pharmacokinetic models were developed using a population-based approach. Both regimens were well tolerated. There was an expected increase in the rate-corrected electrocardiographic QT interval which was independent of pregnancy and treatment. Two pregnant and two nonpregnant women had Plasmodium falciparum parasitemia which cleared within 48 h, and no other subject became slide positive for malaria during 42 days of follow-up. Of 30 pregnant women followed to delivery, 27 (90%) delivered healthy babies and 3 (10%) had stillbirths; these obstetric outcomes are consistent with those in the general population. The area under the plasma PQ concentration-time curve (AUC_0–∞) was lower in the pregnant patients (median [interquartile range], 23,721 μg · h/liter [21,481 to 27,951 μg · h/liter] versus 35,644 μg · h/liter [29,546 to 39,541 μg · h/liter]; P < 0.001) in association with a greater clearance relative to bioavailability (73.5 liters/h [69.4 to 78.4] versus 53.8 liters/h [49.7 to 58.2]; P < 0.001), but pregnancy did not influence the pharmacokinetics of DHA. The apparent pharmacokinetic differences between the present study and results from other studies of women with uncomplicated malaria that showed no effect of pregnancy on the AUC_0–∞ of PQ and greater bioavailability may reflect differences in postdose fat intake, proportions of women with malaria, and/or racial differences in drug disposition.     

Clinical Pharmacology of Netilmicin

Pharmacological studies of netilmicin were conducted in 30 cancer patients. After intravenous administration of 50 mg of netilmicin or gentamicin per m² over a 1-h period in 10 patients, the mean peak serum concentrations occurred at the end of the infusion and were 7.6 and 7.3 μg/ml, respectively. At 6 h, the mean serum concentrations of both drugs was 1.1 μg/ml. After intramuscular injection of 50 mg of netilmicin per m² to each of the same 10 patients, the mean peak serum concentration was 5.5 μg/ml and occurred at 1 h, and, at 6 h, the mean serum concentration was 1.4 μg/ml. The mean proportion of netilmicin excreted in urine during 6 h after intramuscular injection was 55%, and after intravenous injection it was 40.9%. Results were similar with gentamicin sulfate. After administering 60 mg of netilmicin per m² intravenously over 30 min every 6 h in 9 patients, the mean peak serum concentration (7.9 μg/ml) occurred at the end of the infusion. The concentration gradually decreased to below 2.0 μg/ml after 4 h. Continuous infusion of 60 mg of netilmicin per m² every 6 h after a 60-mg/m² loading dose in 11 patients produced levels consistently above 2.9 μg/ml, during the initial 6-h infusion, and levels above 2.0 μg/ml for at least 1 week.     

Screening and risk factors of exocrine pancreatic insufficiency in critically ill adult patients receiving enteral nutrition

Introduction

Malnutrition is a frequent problem associated with detrimental clinical outcomes in critically ill patients. To avoid malnutrition, most studies focus on the prevention of inadequate nutrition delivery, whereas little attention is paid to the potential role of exocrine pancreatic insufficiency (EPI). In this trial, we aim to evaluate the prevalence of EPI and identify its potential risk factors in critically ill adult patients without preexisting pancreatic diseases.

Methods

In this prospective cross-sectional study, we recruited 563 adult patients with critical illnesses. All details of the patients were documented, stool samples were collected three to five days following the initiation of enteral nutrition, and faecal elastase 1 (FE-1) concentrations were assayed using an enzyme-linked immunosorbent assay kit. Blood samples were also taken to determine serum amylase and lipase activity.

Results

The percentages of recruited patients with EPI (FE-1 concentration <200 μg/g) and severe EPI (FE-1 concentration <100 μg/g) were 52.2% and 18.3%, respectively. The incidences of steatorrhea were significantly different (P < 0.05) among the patients without EPI, with moderate EPI (FE-1 concentration = 100 to 200 μg/g) and severe EPI (FE-1 concentration < 100 μg/g). Both multivariate logistic regression analysis and z-tests indicated that the occurrence of EPI was closely associated with shock, sepsis, diabetes, cardiac arrest, hyperlactacidemia, invasive mechanical ventilation and haemodialysis.

Conclusions

More than 50% of critically ill adult patients without primary pancreatic diseases had EPI, and nearly one-fifth of them had severe EPI. The risk factors for EPI included shock, sepsis, diabetes, cardiac arrest, hyperlactacidemia, invasive mechanical ventilation and haemodialysis.

Trial registration

{"type":"clinical-trial","attrs":{"text":"NCT01753024","term_id":"NCT01753024"}}NCT01753024     

The Effect of Glycated Hemoglobin and Albumin-Corrected Glycated Serum Protein on Mortality in Diabetic Patients Receiving Continuous Peritoneal Dialysis

♦ Objective:

To explore the effect of glycated hemoglobin (HbA1c) and albumin-corrected glycated serum proteins (Alb-GSP) on the mortality of diabetic patients receiving continuous peritoneal dialysis (PD).

♦ Methods:

In this single-center retrospective cohort study, incident diabetic PD patients from January 1, 2006, to December 31, 2010, were recruited, and followed up until December 31, 2011. The effect of HbA1c and Alb-GSP on mortality was evaluated by Cox proportional hazards models.

♦ Results:

A total of 200 patients (60% male, mean age 60.3 ± 10.6 years) with a mean follow-up of 29.0 months (range: 4.3 – 71.5 months) were recruited. Sixty-four patients died during the follow-up period, of whom 21 died of cardiovascular disease (CVD). Mean values for HbA1c, GSP and Alb-GSP were 6.7% (range: 4.1 – 12.5%), 202 μmol/L (range: 69 – 459 μmol/L), and 5.78 μmol/g (range: 2.16 – 14.98 μmol/g), respectively. The concentrations of GSP and Alb-GSP were closely correlated with HbA1c (r = 0.41, p < 0.001 and r = 0.45, p < 0.001, respectively). In multivariate Cox proportional hazards models, patients with HbA1c ≥ 8% were associated with increased risk of all-cause mortality (hazard ratio [HR] = 2.29, 95% confidence interval [CI]: 1.06 – 4.96, p = 0.04), but no increased mortality in patients with 6.0% ≤ HbA1c ≤ 7.9%. Patients with Alb-GSP ≤ 4.50 μmol/g had increased all-cause and non-cardiovascular mortality (HR = 2.42, 95% CI: 1.13 – 5.19, p = 0.02; and HR = 2.98, 95% CI: 1.05 – 8.48, p = 0.04 respectively).

♦ Conclusions:

Increased HbA1c and decreased Alb-GSP may be associated with poorer survival in diabetic PD patients, with a non-significant trend observed for poorer survival with the highest level of Alb-GSP.     

Pharmacokinetics of Hydroxymethylnitrofurazone,a Promising New Prodrug for Chagas' Disease Treatment

Hydroxymethylnitrofurazone (NFOH) is a trypanocidal prodrug of nitrofurazone (NF), devoid of mutagenic toxicity. The purpose of this work was to study the chemical conversion of NFOH into NF in sodium acetate buffer (pH 1.2 and 7.4) and in human plasma and to determine preclinical pharmacokinetic parameters in rats. At pH 1.2, the NFOH was totally transformed into NF, the parent drug, after 48 h, while at pH 7.4, after the same period, the hydrolysis rate was 20%. In human plasma, 50% of NFOH was hydrolyzed after 24 h. In the investigation of kinetic disposition, the concentration of drug in serum versus time curve was used to calculate the pharmacokinetic parameters after a single-dose regimen. NFOH showed a time to maximum concentration of drug in serum (T_max) as 1 h, suggesting faster absorption than NF (4 h). The most important results observed were the volume of distribution (V) of NFOH through the tissues, which showed a rate that is 20-fold higher (337.5 liters/kg of body weight) than that of NF (17.64 liters/kg), and the concentration of NF obtained by in vivo metabolism of NFOH, which was about four times lower (maximum concentration of drug in serum [C_max] = 0.83 μg/ml; area under the concentration-time curve from 0 to 12 h [AUC_0–12] = 5.683 μg/ml · h) than observed for administered NF (C_max = 2.78 μg/ml; AUC_0–12 = 54.49 μg/ml · h). These findings can explain the superior activity and lower toxicity of the prodrug NFOH in relation to its parent drug and confirm NFOH as a promising anti-Chagas'' disease drug candidate.     

Identification of potential serum biomarkers of acute paraquat poisoning in humans using an iTRAQ quantitative proteomic

Paraquat (PQ) poisoning has high mortality rates in many countries. Due to it readily being absorbed through the gastrointestinal tract and rapidly excreted in the urine, few biomarkers possess satisfactory specificity and sensitivity in diagnostic and forensic practices. To investigate serum biomarkers in patients with PQ poisoning, pooled sera was analyzed using a proteomic approach based on iTRAQ coupled LC-MS/MS. Of the 413 proteins identified with high confidence, 81 were found to be differentially expressed (1.5-fold change) in the sera of patients with PQ poisoning. The differential expression pattern of 4 of these proteins was validated by enzyme-linked immunosorbent assay (ELISA) in clinical samples. A sera sample from a PQ poisoning patient has shown relatively increased abundance of S100A8 and S100A9. The overexpression of S100A8 and S100A9 was further validated in the lung tissue of PQ-treated rat associated with lung damage. Meanwhile, we identified another two down-expressed proteins, transferrin receptor protein 1 (TfR1) and serum amyloid P-component (SAP), which may be also practicable in human clinical samples as PQ poisoning serum biomarkers. Furthermore, receiver operating characteristic curve analysis confirmed that the expression levels of S100 alarmins, TfR1 and SAP in patient serum could provide a discriminatory diagnostic test for predicting PQ poisoning in patients. Therefore, our results suggest that increased serum levels of S100 alarmins and decreased serum levels of TfR1 and SAP may constitute potential biomarkers for the prediction of PQ poisoning in humans, and might be novel therapeutic targets in PQ poisoning.

Using an iTRAQ quantitative proteomic, S100 alarmins, TfR1 and SAP have been discovered as potential indicators to paraquat poisoning in humans.     

Penicillin Therapy of Experimental Endocarditis Induced by Tolerant Streptococcus sanguis and Nontolerant Streptococcus mitis

The response of tolerant Streptococcus sanguis and nontolerant Streptococcus mitis infections to penicillin therapy was compared in the rabbit model of endocarditis. The minimal inhibitory and bactericidal concentrations of penicillin were 0.1 and 0.1 μg/ml, respectively, for S. mitis and 0.05 and 6.2 μg/ml, respectively, for S. sanguis. Time-kill studies done in vitro with penicillin concentrations of 2 and 20 μg/ml demonstrated minimal killing of the tolerant strain, with a 3 log difference in survival between the two strains after 24 and 48 h. Both strains produced endocarditis with comparable bacterial densities on the valvular vegetations. Rabbits were treated with procaine penicillin G in two dosage regimens, 80,000 or 5,000 U/kg given every 8 h. There was no difference between bacterial densities in valvular vegetations removed from rabbits infected with either strain after 2, 4, or 6 days of treatment with the high-dose regimen (serum penicillin concentration at 0.5 h, 9.4 μg/ml), despite the fact that serum bactericidal activity against the tolerant strain at 0.5 h was minimal. With the low-dose penicillin regimen (serum concentration at 0.5 h, 2.5 μg/ml), therapy was significantly less effective in the tolerant group only after 6 days of treatment. Similar results were obtained when penicillin was administered in low and high doses to prevent infection. In this animal model of infection, penicillin tolerance was associated with a diminished response to penicillin therapy only when the dose was severely restricted. In the high-dose regimen, there was no difference in the response to penicillin therapy between animals infected with either strain, despite the presence of only minimal serum bactericidal activity in the rabbits infected with the tolerant strain.     

Cavitary Penetration of Levofloxacin among Patients with Multidrug-Resistant Tuberculosis

A better understanding of second-line drug (SLD) pharmacokinetics, including cavitary penetration, may help optimize SLD dosing. Patients with pulmonary multidrug-resistant tuberculosis (MDR-TB) undergoing adjunctive surgery were enrolled in Tbilisi, Georgia. Serum was obtained at 0, 1, 4, and 8 h and at the time of cavitary removal to measure levofloxacin concentrations. After surgery, microdialysis was performed using the ex vivo cavity, and levofloxacin concentrations in the collected dialysate fluid were measured. Noncompartmental analysis was performed, and a cavitary-to-serum levofloxacin concentration ratio was calculated. Twelve patients received levofloxacin for a median of 373 days before surgery (median dose, 11.8 mg/kg). The median levofloxacin concentration in serum (C_max) was 6.5 μg/ml, and it was <2 μg/ml in 3 (25%) patients. Among 11 patients with complete data, the median cavitary concentration of levofloxacin was 4.36 μg/ml (range, 0.46 to 8.82). The median cavitary/serum levofloxacin ratio was 1.33 (range, 0.63 to 2.36), and 7 patients (64%) had a ratio of >1. There was a significant correlation between serum and cavitary concentrations (r = 0.71; P = 0.01). Levofloxacin had excellent penetration into chronic cavitary TB lesions, and there was a good correlation between serum and cavitary concentrations. Optimizing serum concentrations will help ensure optimal cavitary concentrations of levofloxacin, which may enhance treatment outcomes.     

Clinical Pharmacology of Ceftriaxone in Patients with Neoplastic Disease

Pharmacological studies of ceftriaxone, a new semisynthetic cephalosporin, were conducted in 35 cancer patients. This antibiotic was administered in a variety of doses and schedules with no observed toxicity. Intramuscular administration of 500 mg of ceftriaxone to seven patients produced mean peak serum concentrations of 32.9 μg/ml 2.0 h after administration. The terminal serum half-life was 10.9 h. Intravenous infusion of 500 mg of ceftriaxone over 5 min to the same group of seven patients produced a mean peak concentration of the drug in serum of 83 μg/ml at the end of administration which decreased to 16.8 μg/ml at 8 h. A dose of 1 g of ceftriaxone given in identical fashion to the same group of seven patients produced mean peak concentrations in serum of 130 μg/ml at the end of administration and 17.3 μg/ml at 12 h. The mean percentages of drug recovered in urine 12 h after single intravenous doses of 500 mg and 1 g were 30 and 20%, respectively. A 1-g dose of ceftriaxone was administered every 8 h to 10 patients, and a 2-g dose was administered every 12 hours to 9 patients. Drug concentrations in serum were measured for each patient after drug administration on day 1, day 3 or 4, and day 7 or 8. The 1-g dose produced an observed mean peak concentration of 154 μg/ml and a mean terminal-phase half-life of 5.6 h on day 3 or 4. The 2-g dose produced a mean peak concentration in serum of 262 μg/ml and a terminal-phase serum half-life of 6.3 h on day 3 or 4. Continuous infusion studies were performed in nine neutropenic patients for up to 8 days by using a loading dose of 1 g over 30 min, followed by 2 g every 8 h. Mean concentrations in serum were maintained at about 135 μg/ml during the infusion period.     

Alveolar–arterial partial pressure difference as an early predictor for patients with acute paraquat poisoning

ObjectiveParaquat (PQ) is associated with high mortality rates in acute poisoning. This study aimed to determine the importance of the alveolar–arterial partial pressure difference (A-aDo₂) in the expected consequences of acute PQ poisoning.MethodsPatients who were hospitalized for PQ poisoning in 2018 were enrolled in this retrospective study. A-aDo₂ data were collected. Multivariate analysis was performed using binary logistic regression to determine whether A-aDo₂ is an independent risk factor for mortality from PQ.ResultsA total of 352 cases were analyzed. The mean PQ dose was 36.84 ± 50.30 mL (0.3–500 mL). There were 185 survivors and 167 non-survivors. The mean A-aDo₂ was not significantly correlated between survivors and non-survivors on day 1. However, there were significant differences in A-aDo₂ between survivors and non-survivors on days 3, 7, 14, and 21. Increased A-aDo₂ values were correlated with an increased mortality rate. The mean A-aDo₂ on day 14 showed the most significant difference between survivors and non-survivors.ConclusionOur study suggests that A-aDo₂ plays an important role as a reference index, which could be a useful predictor in assessing acute PQ poisoning, especially on the 14th day after onset of poisoning.     

Enzymatic hydrolysis using bacterial cultures as a novel method for obtaining antioxidant peptides from brewers' spent grain

Brewers'' spent grain was used as a substrate to obtain protein hydrolysates with antioxidant activity. Hydrolysis was conducted in the culture using proteolytic bacteria. Hydrolysis was controlled by measurement of α-amino group concentration and with the aid of size exclusion chromatography. For each culture the degree of hydrolysis was calculated. The most efficient protein hydrolysis was observed in the cultures of Bacillus cereus (43.06%) and Bacillus lentus (41.81%). In addition, gelatin zymography was performed in order to detect bacterial proteases and their activity. The profile of secreted enzymes was heterogeneous, while the greatest variety was observed for Bacillus polymyxa. Brewers'' spent grain protein hydrolysates exhibited high antioxidant activity. Bacillus subtilis and Bacillus cereus post-cultured media displayed the highest activity, respectively 1291.97 and 1621.31 μM TEAC per g for ABTS, 188.89 and 160.93 μM TEAC per g for DPPH, and 248.81 and 284.08 μM TEAC per g for the FRAP method.

Hydrolysis of brewers'' spent grain conducted in the bacterial cultures entails reduction of workload, economic cost and environmental impact.