Use of liquid chromatography-mass spectrometry in the analysis of residues of antibiotics in meat and milk

The advent of affordable LC-MS systems has led to a massive increase in a number of publications describing quantitative methods for the analysis and confirmation of veterinary drug residues. The lack of volatility and thermal instability of many antibiotics makes LC-MS the method of choice for their analysis. In the review, analytical methods for the determination of residues of each of the major classes of antibiotics are presented.     

Pleural effusions in the medical ICU: prevalence, causes, and clinical implications

OBJECTIVE: To determine the prevalence and causes of pleural effusions in patients admitted to a medical ICU (MICU). DESIGN: Prospective. SETTING: MICU in a tertiary care hospital. PATIENTS: One hundred consecutive patients admitted to the MICU at the Medical University of South Carolina whose length of stay exceeded 24 h had chest radiographs reviewed daily and chest sonograms performed within 10 h of their latest chest radiograph. RESULTS: The prevalence of pleural effusions in 100 consecutive MICU patients was 62%, with 41% of effusions detected at admission. Fifty-seven of 62 (92%) pleural effusions were small. Causes of pleural effusions were as follows: heart failure, 22 of 62 (35%); atelectasis, 14 of 62 (23%); uncomplicated parapneumonic effusions, seven of 62 (11%); hepatic hydrothorax, five of 62 (8%); hypoalbuminemia, five of 62 (8%); malignancy, two of 62 (3%); and unknown, three of 62 (5%). Pancreatitis, extravascular catheter migration, uremic pleurisy, and empyema caused an effusion in one instance each. Heart failure was the most frequent cause of bilateral effusions (13/34 [38%]). When compared with patients who never had effusions during their MICU stay, patients with pleural effusions were older (54+/-2 years, mean+/-SEM, vs 47+/-2 years [p=0.04]), had lower serum albumin concentration (2.4+/-0.1 vs 3.0+/-0.01 g/dL [p=0.002]), higher acute physiology and chronic health evaluation II scores during the initial 24 h of MICU stay (17.2+/-1.1 vs 12+/-1.2 [p=0.010]), longer MICU stays (9.8+/-1.0 vs 4.6+/-0.7 days [p=0.0002]), and longer mechanical ventilation (7.0+/-1.3 vs 1.9+/-0.7 days [p=0.004]). No patient died as a direct result of his or her pleural effusion. Chest radiograph readings had good correlation with chest sonograms (p<0.0001). CONCLUSION: Pleural effusions in MICU patients are common, and most are detected by careful review of chest radiographs taken with the patient in erect or semierect position. When clinical suspicion for infection is low, observation of these effusions is warranted initially, because most are caused by noninfectious processes that should improve with treatment of the underlying disease.     

International and regional standardization of immunoenzyme tests: methods, concerns and limitations]

Numerous attempts have been made to standardise immuno-enzyme techniques (enzyme-linked immunosorbent assay: ELISA) used for the diagnosis of infectious diseases, in order to improve the reproducibility of the tests, expression of results, choice of a positive threshold, and selection of reference samples. The international standardisation of reagents and test protocols appears essential for quality control and the comparison of results between laboratories, but the interpretation of results can encounter major differences depending on the geographical sector under study. Based on these studies, and in the light of a model indirect ELISA for detecting antibodies against Trypanosoma vivax in cattle, the author proposes the international standardisation of reagents, test protocol, and the expression of results of ELISA using international reference samples. For local standardisation, the following proposals are made: sampling of representative local populations. Establishment of the distribution patterns of infected and uninfected local populations. Selection of representative controls from local populations (secondary reference samples). Expression of test results in comparison with these controls. Establishment of internal quality control based on the response of controls. Determination of a positive threshold, in accordance with the requirements of the user. Adaptation of the positive threshold according to the prevalence observed in the geographical sector under study.     

Traditional tests and job simulations: Minority and majority performance and test validities.

Performance of 565 minority and 414 majority job applicants on traditional paper-and-pencil tests and on a telephone simulation that measured similar constructs was assessed. Models of the measurement characteristics of these 2 test batteries indicated larger subgroup mean differences on the traditional tests than on the simulation. Correlations between traditional tests were lower in the majority sample than in the minority sample, and the variance of the minority candidates' scores on the traditional tests was much larger than the variance of majority applicants' scores on the same measures. The validity of the simulation was lower than the validity of the traditional tests. This study replicates previous laboratory research that has indicated smaller subgroup differences on simulations than on paper-and-pencil tests and extends this research by providing evidence of the relative validity of these 2 types of measures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitions, test anxiety, and test performance: A closer look.

Used a thought-listing procedure to investigate the cognitions of 207 undergraduates who varied in test anxiety (high, moderate, low), as measured by the Test Anxiety Scale, and past achievement levels (high, low). Ss were assessed at different points (beginning, middle, end) during a final exam. The dependent variables included 7 categories of thoughts, semantic differential scales to assess the meaning of tests, and exam grade. Results generally replicate previous research findings with the exception that thought-list generated cognitions did not vary as a function of test anxiety level per se. It is concluded that (1) there is no significant relationship between test anxiety and performance on an in-course exam, (2) there is no significant relationship between frequency of cognitions and exam performance, and (3) different cognitive assessment methods may yield different pictures of cognitive phenomena. (6 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reactions to cognitive ability tests: The relationships between race, test performance, face validity perceptions, and test-taking motivation.

The relationships among race, face validity perceptions, test-taking motivation, and test performance on a cognitive ability test were examined. Undergraduates completed 2 parallel cognitive ability tests and a test reactions measure. Results showed that test-taking motivation was related positively to subsequent performance on a parallel test even after the effects of race and performance on the first test were controlled. The effect of race on subsequent test performance was found to be mediated partially by motivation that provided evidence that some portion of the Black–White difference in test performance may be explained through differences in test-taking motivation. Results also indicated that Black–White differences in face validity perceptions of the test may be a function of Black–White differences in test performance. Face validity perceptions of the test affected subsequent performance on the parallel test but only indirectly through test-taking motivation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The causes, prevalence and clinical aspects of nutritional insufficiency

The health of a man is predetermined to a considerable extent by his nutrition. Army physicians frequently deals with the cases of insufficient nutrition among servicemen. The article studies the reasons, frequency and clinic aspects of insufficient nutrition. The authors give a historical reference about the notion of nutritional dystrophy, and reveals some mechanisms of its development. These considerations concerning the cases of insufficient nutrition in servicemen will help army physician to carry out a more effective preventive work among military contingency.     

Pine oil toxicity in the horse: drug detection, residues and pathological changes

Histochemical activity of hydroxysteroid dehydrogenases as well as alkaline and acid phosphatase was investigated in porcine granulosa cells cultured in vitro. Granulosa cells, isolated from preovulatory procine ovarian follicles, during in vitro culture showed activity of enzymes participating in steroid biosynthesis. High activity of delta53betta0H-SDH and G6P-DH as well as the activity of alkaline phosphatase, appearing in the course of culture, could be evidence of progressive luteinization of the cells. Activity of 17beta0H-SDH was lower and exhibited strong fluctuations, similarly low was 20xOH-SDH. Gonadotropic hormones caused the increase of synthesis and accumulation of intracellular lipids. They stimulated alkaline and acid phosphatase, and also the activity of the dehydrogenases. LH had the most visible effect. Estradiol stimulated the activity of acid but not alkaline phosphatase and was not influencing, even lowering the activity of dehydrogenases.     

Antimicrobial drug use in hospitals in The Netherlands, Germany and Belgium

Data on the use of antimicrobial drugs was collected by means of an inquiry to 30 hospitals in Belgium (15 in Dutch sectors and 15 in the French sectors), 21 hospitals in Germany and 20 hospitals in the Netherlands. The use of these drugs was expressed as the number of defined daily doses (DDD) per 100 bed days by the anatomical therapeutical chemical classification system. The total use of antimicrobial agents was significantly (p < 0.001) higher in both parts of Belgium (55.6 and 52.0 DDD per 100 bed days) than in Germany (37.9 DDD) or the Netherlands (34.1 DDD). In particular, amoxicillin-clavulanic acid, the first- and second-generation cephalosporins, aminoglycosides and fluoroquinolones were used more in Belgium than in either of the other countries. At least part of the differences observed in antimicrobial drug use could be explained by differences in written antibiotic policy.     

Organochlorine pesticide residues in cow''s milk and butter in Mexico

In the chipmunk, a mammalian hibernator, a 140 kDa protein complex found in the blood, drastically decreases in concentration during hibernation. This complex contains four species of proteins, HP-20, -25, -27 and -55. In the present study, cDNA clones coding for the chipmunk HP-55 were isolated from a liver cDNA library. Sequence analysis revealed that HP-55 is produced as a precursor protein of 413 amino acids (aa), that it has a signal peptide of 24 aa, and that it contains four potential N-glycosylation sites. The deduced aa sequence shows 63% identity with that of rat alpha1-antitrypsin (alpha1-AT); however, the sequence corresponding to the reactive center P1-P1' residues was found to be Met-Leu, whereas it is Met-Ser in the rat alpha1-AT. During screening of the chipmunk liver cDNA library, four other related classes of cDNA clones were obtained, each also coding for an alpha1-AT-like protein. In spite of more than 86% overall aa sequence identity among the five chipmunk alpha1-AT-like proteins, they are highly divergent in the putative reactive center region; the putative P1-P1' sequences are Met-Leu (HP-55 or CM55-ML), Met-Met (CM55-MM), Met-Ser (CM55-MS), Ser-Ile (CM55-SI) and Ser-Thr (CM55-ST). Each of the alpha1-AT-like protein mRNAs was expressed in chipmunk liver, and the HP-55 mRNA level was greatly reduced during hibernation. Genomic Southern blot analysis and screening of a liver cDNA library from another hibernating squirrel species, the ground squirrel, also revealed expression of multiple members of the alpha1-AT gene family, whereas analysis of a cDNA library from a non-hibernating species, the tree squirrel, found only a single alpha1-AT gene.     

Encouragement, anxiety, and test performance.

"To determine the effect of encouragement on the individual test performance of Ss with varying amounts of anxiety, two anxiety scales were first administered to a sample of college students… three groups of Ss were selected and designated low-, medium-, and high-anxiety. To each S was individually administered the MacQuarrie Test for Mechanical Ability… . On the basis of scores on this test, each anxiety category was divided into two equated groups. Six weeks later the test was again individually administered to each S, this time encouraging comments being offered between subtests to one group in each category but not to the other. Two-tailed t tests revealed only one significant finding: the performance of the low-anxiety Ss displayed increased variability under encouragement." 23 references. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Children with minimal sensorineural hearing loss: prevalence, educational performance, and functional status

OBJECTIVE: This study was designed to determine the prevalence of minimal sensorineural hearing loss (MSHL) in school-age children and to assess the relationship of MSHL to educational performance and functional status. DESIGN: To determine prevalence, a single-staged sampling frame of all schools in the district was created for 3rd, 6th, and 9th grades. Schools were selected with probability proportional to size in each grade group. The final study sample was 1218 children. To assess the association of MSHL with educational performance, children identified with MSHL were assigned as cases into a subsequent case-control study. Scores of the Comprehensive Test of Basic Skills (4th Edition) (CTBS/4) then were compared between children with MSHL and children with normal hearing. School teachers completed the Screening Instrument for Targeting Education Risk (SIFTER) and the Revised Behavior Problem Checklist for a subsample of children with MSHL and their normally hearing counterparts. Finally, data on grade retention for a sample of children with MSHL were obtained from school records and compared with school district norm data. To assess the relationship between MSHL and functional status, test scores of all children with MSHL and all children with normal hearing in grades 6 and 9 were compared on the COOP Adolescent Chart Method (COOP), a screening tool for functional status. RESULTS: MSHL was exhibited by 5.4% of the study sample. The prevalence of all types of hearing impairment was 11.3%. Third grade children with MSHL exhibited significantly lower scores than normally hearing controls on a series of subtests of the CTBS/4; however, no differences were noted at the 6th and 9th grade levels. The SIFTER results revealed that children with MSHL scored poorer on the communication subtest than normal-hearing controls. Thirty-seven percent of the children with MSHL failed at least one grade. Finally, children with MSHL exhibited significantly greater dysfunction than children with normal hearing on several subtests of the COOP including behavior, energy, stress, social support, and self-esteem. CONCLUSIONS: The prevalence of hearing loss in the schools almost doubles when children with MSHL are included. This large, education-based study shows clinically important associations between MSHL and school behavior and performance. Children with MSHL experienced more difficulty than normally hearing children on a series of educational and functional test measures. Although additional research is necessary, results suggest the need for audiologists, speech-language pathologists, and educators to evaluate carefully our identification and management approaches with this population. Better efforts to manage these children could result in meaningful improvement in their educational progress and psychosocial well-being.     

Video-based versus paper-and-pencil method of assessment in situational judgment tests: Subgroup differences in test performance and face validity perceptions.

On the basis of a distinction between test content and method of testing, the present study examined several conceptually and practically important effects relating race, reading comprehension, method of assessment, face validity perceptions, and performance on a situational judgment test using a sample of 241 psychology undergraduates (113 Blacks and 128 Whites). Results showed that the Black–White differences in situational judgment test performance and face validity reactions to the test were substantially smaller in the video-based method of testing than in the paper-and-pencil method. The Race x Method interaction effect on test performance was attributable to differences in reading comprehension and face validity reactions associated with race and method of testing. Implications of the findings were discussed in the context of research on adverse impact and examinee test reactions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Caffeine, performance, and metabolism during repeated Wingate exercise tests

Investigations examining the ergogenic and metabolic influence of caffeine during short-term high-intensity exercise are few in number and have produced inconsistent results. This study examined the effects of caffeine on repeated bouts of high-intensity exercise in recreationally active men. Subjects (n = 9) completed four 30-s Wingate (WG) sprints with 4 min of rest between each exercise bout on two separate occasions. One hour before exercise, either placebo (P1; dextrose) or caffeine (Caf; 6 mg/kg) capsules were ingested. Caf ingestion did not have any effect on power output (peak or average) in the first two WG tests and had a negative effect in the latter two exercise bouts. Plasma epinephrine concentration was significantly increased 60 min after Caf ingestion compared with P1; however, this treatment effect disappeared once exercise began. Caf ingestion had no significant effect on blood lactate, O2 consumption, or aerobic contribution at any time during the protocol. After the second Wingate test, plasma NH3 concentration increased significantly from the previous WG test and was significantly higher in the Caf trial compared with P1. These data demonstrate no ergogenic effect of caffeine on power output during repeated bouts of short-term, intense exercise. Furthermore, there was no indication of increased anaerobic metabolism after Caf ingestion with the exception of an increase in NH3 concentration.     

Tobacco, alcohol, and drug use in a primary care sample: 90-day prevalence and associated factors

The authors reviewed and presented the criteria used to classify the toxic effects of chemicals such as carcinogenic, irritation, corrosive, allergic, and fetotoxicity, as well as dermal absorption of chemical agents. The criteria for assigning symbols to the Polish list of chemical MAC values has not as yet been determined. Following the analysis it may be concluded that all chemical compounds, which satisfy the requirements should be indexed on the MAC list.     

Meaning and measurement of performance rating accuracy: Some methodological and theoretical concerns.

We examined methodological and theoretical issues related to accuracy measures used as criteria in performance-rating research. First, we argued that existing operational definitions of accuracy are not all based on a common accuracy definition; we report data that show generally weak relations among different accuracy operational definitions. Second, different methods of true score development are also examined, and both methodological and theoretical limitations are explored. Given the difficulty of obtaining true scores, criteria are discussed for examining the suitability of expert ratings as surrogate true score measures. Last, the usefulness of using accuracy measures in performance-rating research is examined to highlight situations in which accuracy measures might be desirable criterion measures in rating research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fragile-X: neuropsychological test performance, CGG triplet repeat lengths, and hippocampal volumes

The purpose of this study was to compare a new MR macromolecular contrast medium (MMCM), gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA)-24-cascade-polymer, to a well-studied prototype MMCM, for the potential of distinguishing tissues of varying endothelial permeability. Three tissue models of varying capillary permeability were studied in a total of 46 rats: normal myocardium (normal capillaries), subcutaneously implanted adenocarcinoma (mild capillary leak), and reperfused infarcted myocardium (high capillary leak). TI-weighted MRI was performed before and dynamically after injection of either albumin-(Gd-DTPA)30 or the cascade polymer (each .02 mmol gadolinium [Gd] per kg). Data analysis based on a two-compartment kinetic model yielded estimates of fractional blood volume (BV) (percentage) and fractional leak rate (FLR) (1 per hour). Permeability to the cascade polymer as reflected in FLR was considerable in normal myocardium (8.24 per hour), of similar value in tumors (8.55 per hour), but significantly greater in infarcted myocardium (39.17 per hour, P < .01) versus normal myocardium. The larger albumin-(Gd-DTPA)30 demonstrated minimal extravasation in normal myocardium (FLR .33 per hour); FLR in tumors was 100% higher (.66 per hour, P < .002) and FLR in reperfused capillaries was significantly greater (7.94 per hour, P < .001). Based on capillary permeability measurements, the cascade polymer may have limited utility for detection of mildly increased microvascular permeabilities. For severe tissue injury, the cascade polymer can resolve abnormal microvascular integrity.