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Biomedical subjects

J Meyer

Publications and source records attributed to J Meyer.

At least 415 records · Page 23Linked to original sources
PubMed1996

Circular and linear plasmids of Lyme disease spirochetes have extensive homology: characterization of a repeated DNA element.

We have cloned three copies of a repeated DNA segment from Borrelia burgdorferi sensu stricto strain B31, present on both circular and linear plasmids of this and other B. burgdorferi sensu lato strains. The DNA sequences are characterized by a highly homologous segment containing two open reading frames (ORFs), ORF-A and ORF-B. Five additional ORFs can be found on the slightly less homologous flanking sequences: ORF-G on the opposite strand upstream of ORF-A, and ORF-C, ORF-D, ORF-E, and ORF-F downstream of ORF-B. The 4.6-kb-long element containing ORF-A through ORF-E is flanked by approximately 180-bp-long imperfect inverted repeats (IRs). The putative gene product of ORF-C displays homology to proteins involved in plasmid maintenance in a number of gram-positive and gram-negative bacteria. ORF-E features several short, highly homologous direct repeats. ORF-A, ORF-B, and ORF-D are homologous to three ORFs on a recently described 8.3-kb circular plasmid of Borrelia afzelii Ip21 that are flanked by similar IRs (J. J. Dunn, S. R. Buchstein, L.-L. Butler, S. Fisenne, D. S. Polin, B. N. Lade, and B. J. Luft, J. Bacteriol. 176:2706-2717,1994). ORF-C and ORF-E, however, are missing from this region on the Ip21 plasmid. Furthermore, the repeated DNA element as defined by the IRs is present in opposite orientations relative to the flanking sequences on the B31 and Ip21 plasmids.

Base Sequence↗
PubMed1996

SOX20, a new member of the SOX gene family, is located on chromosome 17p13.

SOX genes share a high sequence identity with the HMG box present in the testis determining gene SRY. We have identified a HMG box-like sequence motif on six contiguous cosmids, which cross-hybridize to a SOX9 cDNA probe. A data base search revealed a high similarity of the deduced amino acid sequence to the human SOX12 and the murine Sox16 HMG domains. The cosmids were assigned to chromosome 17p13 by FISH analysis.

Amino Acid Sequence↗
PubMed1996

How well are FREQUENCY SENSITIVITIES OF grasshopper ears tuned to species-specific song spectra?

Grasshoppers of 20 acridid species were examined using spectral analysis, laser vibrometry and electrophysiology to determine whether the song spectra, the best frequencies of tympanal-membrane vibrations and the threshold curves of the tympanal nerves are adapted to one another. The songs of almost all species have a relatively broad-band maximum in the region between 20 and 40 kHz and a narrower peak between 5 and 15 kHz. There are clear interspecific differences in the latter, which are not correlated with the length of the body or of the elytra. At the site of attachment of the low-frequency receptors (a-cells), the tympanal membrane oscillates with maximal amplitude in the region from 5 to 10 kHz. At the attachment site of the high-frequency receptors (d-cells), there is also a maximum in this region as well as another around 15-20 kHz. The tympanal nerve is most sensitive to tones between 5 and 10 kHz, with another sensitivity maximum between 25 and 35 kHz. The species may differ from one another in the position of the low-frequency peaks of the membrane oscillation, of the nerve activity and of the song spectra. No correlation was found between the characteristic frequency of the membrane oscillation and the area of the tympanal membrane. Within a given species, the frequency for maximal oscillation of the membrane at the attachment site of the low-frequency receptors and the frequency for maximal sensitivity of the tympanal nerve are in most cases very close to the low-frequency peak in the song spectrum. In the high-frequency range, the situation is different: here, the position of the peak in the song spectrum is not correlated with the membrane oscillation maximum at the attachment site of the high-frequency receptors, although there is a correlation between the song spectrum and the sensitivity of the tympanal nerve. On the whole, therefore, hearing in acridid grasshoppers is quite well adjusted to the frequency spectra of the songs, partly because the tympanal membrane acts as a frequency filter in the low-frequency range.

Journal Article↗
PubMed1996

Interspecies scaling of tolcapone, a new inhibitor of catechol-O-methyltransferase (COMT). Use of in vitro data from hepatocytes to predict metabolic clearance in animals and humans.

1. In the present study, in vivo pharmacokinetic data in animals were combined with in vitro metabolic data from animal and human hepatocytes to predict the human systemic plasma clearance and the kinetic profile of tolcapone, a compound metabolized by phase II reactions. 2. The integration of in vitro metabolic data from hepatocytes into allometric scaling gave satisfactory predictions of metabolic clearance in humans for tolcapone (74.2 ml/min predicted versus 118 ml/min observed). 3. Using combined time transformations and in vitro metabolic rates, the range of values predicted from the various animal species (90.4 to 242 ml/min, 0.60 to 2.2 h and 7.3 to 121 for clearance, half-life and volume of distribution, respectively) were in good agreement with the observed values in humans (118 ml/min, 1.3 h and 8.6 h, respectively). 4. Compared to the conventional correction factors (e.g. maximum life span, brain weight), in vitro metabolic data provide a more rational basis for extrapolating the metabolic clearance in humans.

Animals↗
PubMed1996

[Normalization of myocardial perfusion reserve after coronary stent implantation in comparison with balloon angioplasty alone].

Stents scaffold coronary arteries after angioplastic treatment and inhibit elastic recoil resulting in a larger and more circular focal lumen. In 25 patients with significant stenoses of the left anterior descending coronary artery, presenting no collaterals or myocardial infarction, EKG-gated digital subtraction angiograms were recorded at baseline and during hyperemia induced by intracoronary injection of 12 mg papaverine before and after balloon angioplasty, and after adjunct implantation of a single Palmaz-Schatz stent. Densitometric evaluation revealed the time parameters contrast medium appearance time (MCAT) rise time (RT) and mean transit time (MTT) and maximum intensity (Imax). Myocardial perfusion reserve (MPR1) was calculated as the ratio of baseline MCAT and hyperemic MCAT multiplied by the ratio of hyperemic Imax and baseline Imax while MPR2 was calculated as the ratio of baseline RT and hyperemic RT. Maximum flow ratio (MaxFR) was calculated as the ratio of preprocedural hyperemic MTT and postprocedural hyperemic MTT. Post-stenotic MPR1 increased from 1.36 +/- 0.28 to 2.50 +/- 1.20 and to 3.40 +/- 0.58 (ANOVA p < 0.05), while reference MPR1 remained unchanged with 3.40 +/- 0.60. Post-stenotic MPR2 increased from 1.57 +/- 0.14 to 2.59 +/- 0.86 after balloon angioplasty and to 3.10 +/- 0.41 after stenting (ANOVA p < 0.05), while reference MPR2 remained unchanged with 3.10 +/- 0.40. MaxFR was 2.13 +/- 0.53 after balloon angioplasty and 2.83 +/- 0.35 after stenting (p < 0.05). A good correlation was found between minimal stenosis diameter and MPR1 or MPR2 (MPR1: r = 0.94; MPR2: r = 0.87) and between luminal gain and MaxFR (r = 0.75). A negative correlation was measured between recoil, defined as the difference between inflated balloon diameter and resulting minimal stenosis diameter, and MPR1 and MPR2 and MaxFR (MPR1: r = -0.86; MPR2 r = -0.80; MaxFR r = -0.83). In conclusion, adjunct coronary stent implantation normalized post-stenotic myocardial perfusion immediately in contrast to balloon angioplasty alone resulting from a larger postprocedural lumen and a more pronounced inhibition of elastic recoil.

Adult↗
PubMed1996

[Determination of systolic left ventricular time interval using the doppler technique. Analysis of aortic flow spectrum with transthoracic echocardiography].

UNLABELLED: In 10 healthy volunteers (age 21-28 years; mean age 24.8 years +/- 1.9 years) systolic left ventricular time intervals (STI) were determined by analysis of aortic Doppler flow pattern. This method was compared with conventional calculation of STI, using electrocardiogram, carotid pulse curve and phonocardiography, which were registered in synchronicity to the Doppler examination. Both, CW- and PW Doppler echocardiography constantly showed slightly lower values than the conventional method. This referred to basic measurements as well as to measurements after the application of isoprenaline and quinidine. The PW Doppler method underestimated the conventional method concerning the electromechanic systole (QS2) by on average 3.98%, the left ventricular ejection period (LVET) by on average 2.24% and the pre-ejection period (PEP) by on average 7.3%. Using CW-Doppler-method, QS2 was on average 5.31% and LVET was on average 6.67% smaller than the values determined by conventional method, whereas PEP was overestimated by on average 1.69%. The study documented that positive and negative inotropic pharmacological effects were measured reliably by the Doppler-echocardiographic method. Isoprenaline caused a significant shortening of frequency corrected QS2 (QS2c) from -55 +/- 17 to -85 +/- 20 ms (p < 0.05) using the PW-Doppler method; frequency corrected PEP (PEPc) was shortened from -40 +/- 14 to -67 +/- 14 ms (p < 0.05). The CW Doppler method also showed a statistically significant reduction of QS2c (from -64 +/- 18 to -89 +/- 25 ms; p < 0.05) and PEPc (from -37 +/- 16 to -64 +/- 12; p < 0.05). Likewise, the conventional method demonstrated statistically significant shortening of QS2c and PEPc after application of isoprenaline. LVETc did not change in a state of positive inotropy, no matter which method was used for determination. The negative inotropic effect of quinidine, measured by PW-Doppler, resulted in a prolongation of QS2c from -55 +/- 16 to -32 +/- 24 ms (p < 0.05) and of LVETc from -20 +/- 11 to +6 +/- 17 ms (p < 0.05). Using CW Doppler method, quinidine led to a lengthening of QS2c from -63 +/- 16 to -42 +/- 22 (p < 0.05) and of LVETc from -33 +/- 11 to -12 +/- 8 ms (p < 0.05). The conventional method also demonstrated a statistically significant increase of QS2c and LVETc. None of the 3 methods in question showed a statistically significant alteration of PEPc in the negative inotropic state. CONCLUSIONS: Doppler-echocardiographic analysis of aortic flow pattern constitutes a new method for the measuring of systolic time intervals. Basic values as well as changes due to positive or negative inotropic effects are reliably determined, in comparison with conventional methods the measurements are slightly lower.

Adult↗
PubMed1996

[Comparison of NYHA classification with cardiopulmonary function in patients with chronic heart failure].

In this study a correlation was sought between the NYHA class, the results of cardiopulmonary exercise testing (CPX) and the ejection fraction (EF) measured by echocardiography and scintigraphy. Of 36 patients enrolled, CHF in 20 patients was due to CAD and in 16 patients due to DCM. The NYHA class was determined independently by two cardiologists who were blinded to the CPX, echocardiography or scintigraphy results. Sixteen patients were classified as class II and 20 as class III. As a control, 23 patients without cardiopulmonary disease were examined. The CPX was done according to a ramp protocol with continuous measurement of respiratory gases, maximal oxygen consumption (VO2-max) and oxygen consumption at the anaerobic threshold (VO2-AT). A correlation (p = 0.0425) between the NYHA classification and the Weber classification for VO2-AT was found. There was no correlation for VO2-max. VO2-AT was significantly higher in NYHA II patients as compared to NYHA III patients. No significant difference was seen in relation to the VO2-max. In comparison to the normal group, the VO2-AT and VO2-max were significantly lower in NYHA II and III patients. There was no significant correlation between VO2-AT and EF, VO2-max and EF, or between NYHA class and EF. During a 16-month follow-up period lethality was 8/14 patients with VO2-AT < 10 ml/kg/min. Although the NYHA classification provides a valid method for determining the prognosis of CHF patients, if feasible, the CPX examinations should be used to provide updates of the disease progress.

Adult↗
PubMed1996

Triplane fracture associated with a proximal third fibula fracture.

The case of a Maisonneuve fracture occurring in association with a triplane fracture in an adolescent wrestler is presented. In this combination of injuries, the deltoid ligament may be ruptured, and/or the medial malleolus fractured. If the proximal fibula fracture is not discovered, and the syndesmosis rupture is not treated, the resulting chronic talocrural instability may lead to chronic ankle pain and degenerative arthritis. The orthopedist should be aware of the possibility of a Maisonneuve fracture occurring in association with a triplane fracture, and should treat both injuries appropriately.

Adolescent↗
PubMed1996

The effect of recombinant human erythropoietin on haematopoiesis in patients undergoing haemodialysis.

OBJECTIVE: To define the effect of intravenous recombinant human erythropoietin (rHuEPO) in patients with anaemia caused by chronic renal failure. Data collection included bone marrow response, ferrokinetics, red cell survival as well as the influence on red cell mass and plasma volume. DESIGN: A convenience sample of stable individuals on haemodialysis, with haemoglobin (Hb) levels of less than 80 g/l, was surveyed over a 12-week period while they were receiving the hormone. Blood counts and iron studies were monitored serially, while 51Cr-labelled red cells and 59Fe (III) citrate were used in the radionuclide investigations carried out before and after the course of replacement therapy was completed (pre and post injection). Bone marrow aspiration and trephine biopsy were performed at each of these times. RESULTS: The actual mean trial period was 14 weeks. Eight patients were enrolled but 1 was withdrawn after developing tuberculosis at the start of the study. Haemoglobin levels rose from 59 g/l (SD 8.8) to 96 g/l (SD 13.9) (P < 0.0001); mean red cell mass rose from 675 ml to 954 ml (P < 0.01). Concurrently, the serial studies in 6 patients showed prominent erythroid hyperplasia. Plasma iron turnover increased insignificantly from 42.5 to 118.9 mumol/l/day; erythron turnover increased from 42.5 to 87.3 mumol/l/day (P < 0.01). There was a marked shortening of the marrow transit time from 4.4 to 3.3 days (P < 0.03). Efficacy of erythropoiesis decreased from 1.17 to 0.65 (P < 0.05). Red cell survival was not altered. CONCLUSIONS: The patient with end-stage renal failure remains fully responsive to erythropoietin therapy. This is reflected in improved ferrokinetics, red cell hyperplasia in the marrow and rise in haemoglobin level without alteration in mean erythrocyte lifespan. Simple hormonal replacement is therefore a rational approach to management.

Anemia↗
PubMed1996

[Prospective study of subjective stress caused by dobutamine stress echocardiography--effect on diagnostic accuracy].

UNLABELLED: We used a standardized questionnaire to assess physical and mental distress caused by dobutamine stress echocardiography (DSE). The examination was performed according to a standardized protocol (5-40 micrograms/kg/min including atropine). 91 patients (pts), 68 men (62 +/- 9 years), 23 women (65 +/- 7 years) were asked to quantify the severity of the following symptoms: palpitations, anxiety, headache, nausea, discomfort of left lateral position, angina pectoris and dyspnea. Numbers on a rating scale from 1-10 defined the degree of distress. Absence of a symptom equalled mark, 1, slight expression marks 2-4. Moderate expression was defined by marks 5-7 and very strong expression by marks 8-10. RESULTS: 86% of pts felt affected by one or more symptoms to a slight to moderate extent (mark 4 +/- 2.17). Palpitations were felt by 85% of the pts (mark 6 +/- 2.83), anxiety by 42% (mark 3 +/- 2.5), headache by 50% (3 +/- 2.54), nausea by 20% (2 +/- 1.72), angina pectoris by 42% (3 +/- 2.5), dyspnea by 30% (2 +/- 2.42) and discomfort of left lateral recumbent position by 43% (mark 3 +/- 2.59). 43 pts underwent coronary angiography. The negative predictive value of DSE to identify pts without a coronary artery stenosis extending a 50% diameter reduction was 85% for the 16 pts who reached their individual submaximal heart rate compared to 60% for those 27 pts who did not reach it. Unspecific symptoms led to test termination in these pts. The positive predictive values were comparable (89 and 94%). CONCLUSION: DSE causes physical and mental distress. If symptoms lead to test termination before age corrected submaximal heart rate is reached, normal wall motion does not exclude significant coronary artery disease.

Angina Pectoris↗
PubMed1996

[Automatic report documentation in cardiology using a speech recognition system].

Computer systems that can convert spoken text into written text have recently become available. In one such system, the phonetics of spoken words are compared with those of 32 000 stored words, with a statistical program helping to choose the word with the highest probability of being correct. We evaluated the practicability of the IBM Voice Type system for writing medical reports using a cardiologic vocabulary. A total of 200 medical documents were generated with a mean of 301 +/- 52 words. In the mean, 12 +/- 5 words were falsely recognized in each document, resulting in a rate of correct recognition of 95.1 +/- 2.5%. It is possible to correct a falsely recognized word by choosing an alternative word from a provided list, which worked in our case in 51% (6.1 +/- 2.8 words in each document). Correction of falsely recognized words had to be done by manual input 49% of the time (5.9 +/- 2.9 words in each document). The mean time demand for word correction amounted to 57 +/- 15 s for each document, whereas correction by manual input needed more time (37 +/- 14 s) than choosing from a list of alternative words (20 +/- 4s). A requirement for use of the Voice Type system is a reduced speech rate. Dictation of our documents took on average 260 s when done with a normal speech rate, and 400 s when done at a reduced speech rate. In conclusion, automatic writing of cardiologic reports can be done easily and with a low failure rate using the IBM Voice Type system with a cardiologic vocabulary. It takes about 3 min longer to create a medical text 1 1/2 pages long which is free of mistakes by using the Voice Type system than to simply dictate the text. Time can be saved by eliminating the need to check a preliminary report. The major advantage of automated reporting is that the written report is immediately available. For each discipline, specific vocabularies should be validated.

Cardiology↗
PubMed1996

[Effect of intracoronary and intravenous iloprost on coronary blood flow velocity in patients with coronary heart disease].

Prostacyclin and its stable analog iloprost (ILO) are able to induce vasomotor effects in smooth muscle cells. These vasodilator effects have been demonstrated in several types of vessels, even in coronary arteries. Bugiardini et al. have previously claimed to have evidence for a coronary steal phenomenon in patients with coronary artery disease receiving ILO. They conclude the steal phenomenon from the appearance of angina and ST-segment changes. The aim of our trial was to study the coronary circulation by measuring coronary vessel diameter, coronary blood flow velocity (CBFV), heart rate and blood pressure in patients with high degree LAD stenosis following i.v. and i.c. infusion of ILO and papaverine (PAPA i.c.). Infusion of ILO i.v. (2 ng kg-1 min-1) induced no significant change in vessel diameter measured in the stenotic and in normal vessel segments. Following ILO i.c. (0.5 ng kg-1 min-1) and PAPA coronary vessel diameter increased proximal to the stenosis by 25.8 +/- 5.6% and 24.8 +/- 4.6% and within the stenosis by 50.1 +/- 10% and 56.2 +/- 11%, respectively (p < 0.01). At the end of the i.c. ILO infusion CBFV increased by 103.7 +/- 24.9% and was further elevated by PAPA (217 +/- 57.2%, p < 0.01). The elevated flow velocity with increased vessel diameter following ILO i.c. (0.5 ng kg-1 min-1) implicated an increased flow in the stenotic vessel and thus there was no evidence for a decreased perfusion or coronary steal phenomenon.

Blood Flow Velocity↗
PubMed1996

[Cardiovascular effects of thyroid hormones].

The heart is a major target organ for thyroid hormone action, and marked changes occur in cardiac function in patients with hypothyroidism or hyperthyroidism. Triiodothyronine (T3)-induced changes in cardiac function can result from direct or indirect T3 effects. Direct T3 effects result from T3 action in the heart itself and are mediated by nuclear or extranuclear mechanisms. Extranuclear T3 effects, which occur independently of nuclear T3 receptor binding and increases in protein synthesis, influence primarily the transport of amino acids, sugars, and calcium across the cell membrane. Nuclear T3 effects are mediated by the binding of T3 to specific nuclear receptor proteins, which results in increased transcription of T3-responsive cardiac genes. The T3 receptor is a member of the ligand-activated transcription factor family and is encoded by cellular erythroblastosis A (c-erb A) genes. T3 increases the heart transcription of the myosin heavy chain (MHC) alpha gene and decreases the transcription of the MHC beta gene, leading to an increase of myosin V1 and a decrease in myosin V3 isoenzymes. Myosin V1, which is composed of two MHC alpha, has a higher myosin ATPase activity than myosin V3, which contains two MHC beta. The globular head of myosin V1, with its higher ATPase activity, leads to a more rapid movement of the globular head of myosin along the thin filament, resulting in an increased velocity of contraction. T3 also leads to an increase in the speed of diastolic relaxation, which is caused by the more efficient pumping of the calcium ATPase of the sarcoplasmic reticulum (SR). This T3 effect results from T3-induced increases in the level of the mRNA coding for the SR calcium ATPase protein, leading to an increased number of calcium ATPase pump units in the SR. Overall, T3 leads to an increase in ATP consumption in the heart. In addition, less chemical energy of ATP is used for contractile purposes and more of it goes toward heat production, which causes a decreased efficiency of the contractile process in the hyperthyroid heart. The pathophysiologic basis for myxedema is the opposite of that discussed for the hyperthyroid heart. In addition to decreased direct effects of thyroid hormone in cardiac myocytes, indirect effects occur through decreases in peripheral oxygen consumption and changes in hemodynamic parameters. Myofibrillar swelling with loss of striation and interstitial fibrosis occurs on histologic examination of hypothyroid hearts. In addition, accumulation of mucopolysaccharide substances (Glycosaminoglycans) can be demonstrated. On electron microscopic examination, mitochondria show disruption and lipid inclusion. Cardiac papillary muscle obtained from animals with hypothyroidism shows a depression of the force velocity curve and reduced rate of tension development, indicating significant contractile abnormalities. In patients with hypothyroidism, a true enhanced incidence of hypertension (increased peripheral vascular resistance) has been found. In addition, hypercholesterolemia and impairment of fatty acid mobilization are associated with myxedema and present additional risk factors for the development of atherosclerotic cardiovascular disease.

Animals↗
PubMed1996

The epidemiology of AIDS/HIV infection: a review for the dentist.

This article reviews 14 recently published articles on the epidemiology of human immunodeficiency virus (HIV) infection. Each article is summarized and evaluated for its usefulness in helping the practicing dentist to perform the various roles of diagnosing and treating disease, managing auxiliary staff, providing community leadership, and educating fellow professionals and patients. Each article was selected based on timeliness, accuracy, and accessibility by a panel of two dental school faculty members, a physician and HIV information specialist, and a school of public health faculty member with extensive experience in HIV and acquired immune deficiency syndrome (AIDS).

Acquired Immunodeficiency Syndrome↗
PubMed1995

[Normal values for dobutamine stress echocardiography].

Dobutamine stress echocardiography having established itself as a sensitive method for diagnosing coronary heart disease, even in the absence of normative values, the physiological haemodynamics as well as the physiological values for global and regional left ventricular myocardial function were measured. TEST PERSONS AND METHODS: 14 healthy subjects (ten men, four women; median age 25 [range 21-32] years) underwent dobutamine stress echocardiography according to an internationally practised dosage steps protocol (5-40 micrograms/kg/min with additional 0.5 mg atropine at 40 micrograms). RESULTS: Maximal infusion rate achieved a serum dobutamine level of 1.67 micrograms/ml with minimal quartiles; it did not influence serum electrolytes (especially potassium). Heart rate increased from 64 to 150/min (P < 0.0001), blood pressure from 111/66 to 158/88 mmHg (systolic: P < 0.0001; diastolic P < 0.001) and the double product of systolic pressure and heart rate from 6714 to 24571 (P < 0.001). While the end-diastolic volume index decreased from 50 to 37 ml/m2 (P < 0.05), the end-systolic volume index fell from 20 to 7 ml/m2 (P < 0.0001). Regional wall motion analysis indicated an increase in left ventricular circumferential contractility with little scatter. CONCLUSIONS: The usual protocol for dobutamine stress echocardiography is a sensible one, because the haemodynamic effect occurs already at low dosage and can then be increased significantly with further dosage steps. High serum dobutamine concentrations can be achieved without arrhythmogenic hypokalaemia. Volume index and ejection fraction are especially discriminatory variables. Quantitative analysis of wall motion is justified because of the low scatter of values.

Adult↗
PubMed1995

Prevalence of myxomatous mitral valve prolapse in patients with lymphocytic thyroiditis.

In conclusion, given the cardiac (mitral regurgitation, endocarditis, thromboembolic complications, arrhythmic sudden death) and neurologic (cerebral embolic event) complications of the pathologic forms of MVP, physicians should look carefully for myxomatous involvement of the mitral valve and prolapse in patients with autoimmune thyroid diseases. Patients should be monitored and prophylactic antibiotic treatment recommended when appropriate.

Adult↗
PubMed1995

Evaluation of liver function tests in neonatal calves.

OBJECTIVE: To evaluate the efficacy of tests for hepatic disease in young calves. DESIGN: Prospective case-control study. ANIMALS: 28 clinically normal calves and 47 calves with histologically proven hepatic disease. PROCEDURE: Liver function tests and serum activity of liver-derived enzymes were determined on 28 clinically normal calves at birth and at 2 weeks of age. These values were compared with the results from 47 calves with hepatic disease verified by histologic examination. Upper limit of confidence interval was determined for the results on the clinically normal calves, and Student's t-test was used to identify significant differences in the data from calves of various age-groups. RESULTS: None of the results of the common tests for liver damage or function (measurement of bilirubin, gamma-glutamyltransferase, glutamate dehydrogenase [GMD], alkaline phosphatase, L-lactate dehydrogenase, aspartate transaminase, or alanine transaminase) were clinically useful when used alone for detection of hepatic disease in calves less than 6 weeks old. Sensitivity of gamma-glutamyltransferase, GMD, aspartate transaminase, and alkaline phosphatase as indicators of hepatic disease in this population of calves was 0, 59, 80, and 9%, respectively. Direct bilirubin (sensitivity, 87%) was more sensitive than total bilirubin (sensitivity, 66%). Serum enzyme activity of most enzymes (P < 0.01), total bilirubin concentration (P < 0.001), and sulfobromophthalein sodium clearance half-life were significantly higher (P < 0.001) in newborn calves than in 2-week-old calves. CLINICAL IMPLICATIONS: Clinical findings that indicate hepatic disease in calves that are less than 6 weeks old could be confirmed by measurement of serum activity of GMD or concentrations of total serum bile acids or direct bilirubin. Percutaneous liver biopsy may still be needed and may provide the most information.

Animals↗