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Investigations of D-lactate metabolism and the clinical signs of D-lactataemia in calves
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Importance of the Effective Strong Ion Difference of an Intravenous Solution in the Treatment of Diarrheic Calves with Naturally Acquired Acidemia and Strong Ion (Metabolic) Acidosis
Get PDFBackground: The effect of sodium bicarbonate on acid-base balance in metabolic acidosis is interpreted differently by
Henderson-Hasselbalch and strong ion acid-base approaches. Application of the traditional bicarbonate-centric approach
indicates that bicarbonate administration corrects the metabolic acidosis by buffering hydrogen ions, whereas strong ion
difference theory indicates that the co-administration of the strong cation sodium with a volatile buffer (bicarbonate)
corrects the strong ion acidosis by increasing the strong ion difference (SID) in plasma.
Objective: To investigate the relative importance of the effective SID of IV solutions in correcting acidemia in calves
with diarrhea.
Animals: Twenty-two Holstein-Friesian calves (4–21 days old) with naturally acquired diarrhea and strong ion (metabolic)
acidosis.
Methods: Calves were randomly assigned to IV treatment with a solution of sodium bicarbonate (1.4%) or sodium
gluconate (3.26%). Fluids were administered over 4 hours and the effect on acid-base balance was determined.
Results: Calves suffered from acidemia owing to moderate to strong ion acidosis arising from hyponatremia and hyper-
D-lactatemia. Sodium bicarbonate infusion was effective in correcting the strong ion acidosis. In contrast, sodium gluconate
infusion did not change blood pH, presumably because the strong anion gluconate was minimally metabolized.
Conclusions: A solution containing a high effective SID (sodium bicarbonate) is much more effective in alkalinizing
diarrheic calves with strong ion acidosis than a solution with a low effective SID (sodium gluconate). Sodium gluconate is
ineffective in correcting acidemia, which can be explained using traditional acid-base theory but requires a new parameter,
effective SID, to be understood using the strong ion approach
Experimentally induced systemic hyperchloremic acidosis in calves
Get PDFBACKGROUND:
Among the various metabolic disturbances occurring in calves affected by neonatal diarrhea or ruminal acidosis, acidemia constitutes an important condition requiring specific therapy. Although various attempts have been made to estimate the degree of metabolic acidosis on the basis of clinical signs alone, some doubts have been raised regarding the accuracy and predictive value of the clinical parameters suggested.
HYPOTHESIS:
The induction of metabolic acidosis in healthy calves via the infusion of hydrochloric acid will lead to a clinical picture similar to that seen in neonatal calves with diarrhea or ruminal acidosis.
ANIMALS:
The study was carried out on 15 Holstein male calves, between 5 and 19 days of age.
METHODS:
Hyperchloremic metabolic acidosis was induced over a period of 80 minutes by an intravenous infusion of 4000 ml of 0.9% NaCl solution containing 400 mmol HCl.
RESULTS:
Acidemia occurred rapidly and increased constantly up to a maximum value which was reached in all calves by the end of the administration and amounted to a 22.4 mmol/liter mean base deficit (range from 17.0 to 33.1 mmol/l ).
Despite the relatively severe acute acid-base imbalance during the entire observation period, no calves showed any clinical signs; even appetite remained normal.
CONCLUSIONS AND CLINICAL IMPORTANCE:
The hypothesis was rejected. Factors other than a disturbance of the acid-base balance should be considered to be primarily responsible for the clinical picture in calves affected by diarrhea or ruminal acidosis
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Comparison of the clinical pictures in experimentally induced metabolic acidosis, hyper-L-lactatemia and hyper-D-lactatemia
No full textIn calves with diarrhoea, systemic acidosis and hyper-L- and D-lactatemia constitute the most important metabolic consequences. Recent studies indicate, however, that clinical signs are determined more by the extent of D-lactate accumulation than by the metabolic acidosis. We summarize the results of different trials in which the single effects of metabolic acidosis, hyper-L-lactatemia, and hyper-D-lactatemia on the clinical condition were studied.
1st trial: induction of metabolic acidosis:
15 Holstein calves received 4.0 l of a 0.1M HCl solution i.v. over a period of 80 minutes (50 ml/min).
The procedure managed to provoke a relatively severe metabolic acidosis, that reached a ABE mean value of -22.4 mmol/l (range -17.0 to -33.1 mmol/l). Despite the acidemia during the entire observation period no calves showed any clinical repercussions.
2nd trial: induction of hyper-L-lactatemia:
5 Holstein calves received 400 ml of a 25% L-lactate solution: 100 ml as i.v. bolus (1 min.), and 300 ml via an i.v. infusion over 35 minutes.
The experimental procedure provoked a severe hyper-L-lactatemia that reached a peak mean value of 25.0 mmol/l at the end of the infusion (range 18.8 to 38.3 mmol/l). No clinical signs accompanied the hyper-L-lactatemia. Signs of metabolic alkalosis were observed.
3rd trial: induction of hyper-D-lactatemia:
5 Holstein calves received 100 ml of a 25% D-lactate solution via an i.v. bolus (1 minute).
A clear increase of the D-lactatemia was observed right from the first control after the administration. At this time the mean value was 16.4 mmol/l (range 13.8 to 18.7 mmol/l). Afterwards the D-lactatemia tended slowly to recover its pre-trial value.
Between eight and 40 minutes after the injection all calves showed the following clinical signs: impairment of the palpebral reflex, somnolence, staggering, prolonged periods of motionless, standing with unphysiological postures, lowered and sometimes waving head, and drooping ears. Calves lay down often and for longer, and had to be helped to rise. No impairment of the sucking reflex was observed. After four hours all calves appeared clinically normal. No deviation of the acid-base balance was observed.
Conclusions
The results of the summarized studies show that with the exception of any impairment of the sucking reflex, all the signs once attributed to metabolic acidosis can be reproduced by inducing hyper-D-lactatemia without acidosis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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