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Biomedical subjects

G T Sanders

Publications and source records attributed to G T Sanders.

At least 19 recordsLinked to original sources
PubMed1992

Clinical evaluation of a pancreatic lipase mass concentration assay.

An immunoactivation assay for determining pancreatic lipase mass concentration was clinically evaluated and compared with results obtained by measuring total amylase and pancreatic amylase activity. A group of 30 patients with pancreatitis was compared with a control group of 32 patients in which this disease was suspected but excluded. Both lipase mass concentration and pancreatic amylase activity exhibit good sensitivity (0.93 each) and specificity (0.94 and 0.97, respectively) at cutoff concentrations of 200 micrograms/L and 200 U/L, respectively. The median increase in lipase mass concentration (37.1 times the upper limit of the reference interval) in the pancreatitis group was higher than that for either total amylase or pancreatic amylase activity (5.94 and 14.5 times, respectively) but showed a similar time to peak value. We conclude that the lipase assay is the method of choice for diagnosing pancreatitis.

Acute Disease↗
PubMed1992

The clinical importance of routine measurement of liver enzymes, total protein and albumin in a general medicine outpatient clinic: a prospective study.

UNLABELLED: The objective was to study the usefulness of routine measurement of liver enzymes (ASAT, ALAT, alkaline phosphatase, gamma-GT), and total protein (TP) and albumin (Alb) in a general medicine outpatient clinic. A prospective study was made of consecutive patients who were classified according to whether or not an indication for the tests was present. All six tests were measured in all patients. Physicians were kept unaware of the results of tests in patients with no indication for ordering the test. The setting was a general internal medicine outpatient clinic in a 850-bed teaching hospital which serves as a referral clinic for general practitioners. There were 615 consecutive patients who were all new referrals to the outpatient clinic. The results of all patients with no indication for the test but who had abnormal results were presented to a panel of three experienced internists who decided whether the results had any clinical importance. Repeat measurements of the tests or follow-up results were obtained in all these patients. Seventy-eight of 320 patients in whom no indication for the test for liver enzymes existed had abnormal results. In only six of these (1.9%) were the abnormalities of clinical significance. In 56 of 449 patients in whom no indications were present for TP and Alb measurement the results were abnormal. In only 2 (0.4%) was this clinically important. CONCLUSION: the routine measurement of these six tests in general medicine outpatient clinics should be abandoned because of the low yield.

Adolescent↗
PubMed1992

Interleukin-6 release and the acute-phase reaction in patients with acute myocardial infarction: a pilot study.

We investigated the potential role of interleukin-6 as a mediator of the acute-phase reaction (APR) in patients with acute myocardial infarction. Of the six patients studied, five demonstrated increased plasma interleukin-6 levels. Interleukin-6 levels began to increase at 14 hours (mean; range = 8 to 20 hours) after the initial complaints and reached maximal levels of 28 to 250 U/mL (normal values less than 10 U/mL) after 36 hours (mean; range = 24 to 52 hours). No correlation was seen between the size of the interfaction as indicated by creatine kinase MB assays and the extent of the interleukin-6 increases (r = 0.44; p = 0.38). As an indicator of the APR, plasma C-reactive protein (CRP) levels were measured. CRP levels began to increase after 16 hours (mean; range = 8 to 24 hours) and reached maximum levels of 56 to 322 mg/L (normal values less than 3 mg/L) after 65 hours (mean; range = 48 to 92 hours). The increase of the interleukin-6 level preceded the increase of the CRP level in three patients and was simultaneous in two patients. Maximal interleukin-6 levels correlated significantly with maximal CRP levels (r = 0.96; p = 0.002). Thus these findings indicate that interleukin-6 is an important endogenous mediator for the APR in patients with acute myocardial infarction.

Acute Disease↗
PubMed1991

Bone-alkaline phosphatase as indicator of bone formation.

Bone-alkaline phosphatase was determined in patients at risk of osteoporosis due to treatment with oral corticosteroids, and in patients at risk of increased bone synthesis because of treatment with cyclosporin. Both a significant decrease of bone-alkaline phosphatase during corticosteroid treatment, and a significant increase of bone-alkaline phosphatase during cyclosporin treatment could be demonstrated. It is concluded that bone-alkaline phosphatase is a useful parameter for monitoring changes in bone formation.

Adult↗
PubMed1991

Multicentre comparison of the Novo Biolabs immunometric CK-MB assay with four established methods.

The analytical performance of a new immunometric CK-MB assay from Novo Biolabs was evaluated in three hospitals. Comparisons were made with another immunometric assay, an immune inhibition/precipitation technique, an immune inhibition method, and a column separation method. The Novo assay exhibited good precision (CV 3-7%) at all concentration levels tested (6-150 micrograms/L) and was found to be linear over the range 0-200 micrograms/L. Comparison of the Novo kit with the other methods using patients' sera showed acceptable correlation between the methods over a wide concentration range (r = 0.96-0.99). We conclude that the assay is a useful adjunct to the specific measurement of CK-MB, particularly in routine laboratories with a high throughput of such determinations.

Creatine Kinase↗
PubMed1991

The course of biochemical parameters of bone turnover during treatment with corticosteroids.

The mechanisms by which glucocorticoids cause osteopenia are incompletely understood. It is generally accepted that bone formation is depressed during corticosteroid treatment, but the cause of the ongoing bone resorption is less clear. Secondary hyperparathyroidism and changes in vitamin D metabolism are thought to play a role. This is based mostly on data from cross-sectional studies in heterogeneous patient groups. We, therefore, studied longitudinally the course of biochemical parameters and the hormones influencing bone turnover in a homogeneous group of 10 euthyroid patients with Graves' ophthalmopathy, all euthyroid for at least 1 yr before, during, and after a 12-week course of prednisone. Bone formation was depressed as reflected by a fall in serum osteocalcin (3.0 +/- 2.1, 1.7 +/- 1.1, and 2.4 +/- 1.9 micrograms/L at weeks 0, 4, and 12, respectively; P = 0.02) and in total alkaline phosphatase (1.15 +/- 0.33, 0.83 +/- 0.22, and 0.88 +/- 0.40 mukat/L; P = 0.001). Parameters of bone resorption (urinary hydroxyproline/creatinine ratio, serum acid phosphatase) and the levels of vitamin D metabolites remained unchanged. Serum intact PTH seemed to decrease slightly. Our findings suggest that glucocorticoid induced osteopenia is caused by a depressed bone formation in the presence of an unaltered but ongoing bone resorption. Secondary hyperparathyroidism and changes in vitamin D metabolism are apparently not involved.

Acid Phosphatase↗
PubMed1990

Inhibition of lactate dehydrogenase isoenzymes by sodium perchlorate evaluated.

We evaluated a method of measuring lactate dehydrogenase isoenzyme 1 (LD-1) selectively (Clin Chem 1987;33:991-2), in which all other LD isoenzymes were inhibited by adding sodium perchlorate to the reaction medium to a final concentration of 0.825 mol/L. In this study we used the different isoenzymes purified from human autopsy tissue and found that the originally published amount of inhibitor (a) increased the original LD-1 activity and (b) did not eliminate all enzyme activity of LD-2 and LD-3. Interference by LD-2 was further demonstrated. Thus we conclude that this method cannot be used for the selective determination of LD-1 because its results do not accurately reflect the original LD-1 activity.

Humans↗
PubMed1990

Macro enzymes: prevalence, composition, detection and clinical relevance.

The presence of a macro enzyme, i.e. an enzyme with an abnormally high molecular weight, frequently leads to a genuinely increased serum activity or an interference in laboratory assays. This may thereby result in false positive diagnoses, such as acute myocardial infarction or pancreatitis. The various forms of macro enzymes are reviewed. In the case of immune complexes the immunoglobulins and (iso)-enzymes involved are discussed, as well as the specificity of the interaction, the prevalence and clinical relevance, associations with autoimmune or other diseases, and their behaviour in laboratory assays.

Adult↗
PubMed1990

Detection and clinical relevance of human endotoxemia.

An optimized chromogenic assay for the detection of endotoxins in human blood is described. The assay comprises the removal of the inhibitory activity of plasma components by a dilution plus heating procedure, endotoxin-dependent activation of Limulus amebocyte lysate, and chromogenic measurement of the activated lysate. The assay has a detection limit of 3 ng endotoxin/L plasma. At the 10 ng/L level within-assay CV and between-assay CV of 14 and 21% were obtained respectively. In a prospective clinical trial including 473 consecutive febrile patients the assay has previously been demonstrated to have positive and negative predictive values of 48% and 99% for impending Gram-negative sepsis, respectively. In a similar study in 76 consecutive patients with Gram-negative infection of the urinary tract, these values were 73% and 95%, respectively. We conclude that this assay may provide the means to select those patients who are most likely to benefit from anti-endotoxin treatment. To facilitate endotoxin testing in other laboratories, a preliminary evaluation of a commercial endotoxin assay versus our own method was performed with 108 duplicate blood samples obtained from septic patients. With this assay detection limits of 2-3 ng endotoxin/L plasma could be obtained, as well as a good correlation (r = 0.94) and level of consensus to establish endotoxemia (93%) as compared to the house method. The commercial assay may therefore facilitate the introduction of endotoxin testing in other laboratories.

Bacterial Infections↗
PubMed1987

Influence of gastric emptying on the PABA test.

Serum and urine PABA curves monitored in 13 healthy volunteers were analysed and compared with curves from 11 healthy volunteers after administration of the gastrokinetic agent domperidone. Both in serum and in urine less variation in the PABA curves was observed after domperidone. Results without domperidone were subdivided in a group with normal gastric emptying (I) and a group with slow gastric emptying (II), based upon the time at which the serum PABA peak was found. Maximal serum PABA concentration, serum PABA at t = 60 min, lagphase and t1/2 for urinary excretion, and % PABA excretion from 0-3 h, 3-6 h and 0-6 h differed significantly between the two groups. Instead, no differences were found between subgroup I and volunteers after concomitant domperidone administration. In summary, PABA test results in serum and urine are influenced by variations in gastric emptying. Domperidone corrects for delayed gastric emptying and thereby narrows the range of normal PABA excretion values.

4-Aminobenzoic Acid↗
PubMed1986

Acid phosphatase in the lysosomal and microsomal fractions of human prostatic epithelium.

Polyacrylamide gel electrophoresis of acid phosphatase from prostatic tissue reveals one more band than seminal plasma. It was attempted to ascertain which subcellular fraction was responsible for that intracellularly localized enzyme. Prostatic epithelium from patients with prostatic hyperplasia was homogenized, and a lysosomal and microsomal fraction were prepared by differential centrifugation. These two fractions were further centrifuged on an isopycnic Percoll gradient. The intracellularly localized form of acid phosphatase was associated with the lysosomal as well as with the microsomal fraction. In a fused rocket electrophoresis experiment these acid phosphatases cross-reacted with antiserum from seminal plasma. After neuraminidase treatment of the acid phosphatase of lysosomal and microsomal origin, only one activity band was found in polyacrylamide gels. It is concluded that only one acid phosphatase protein exists in prostatic epithelium; differences in electrophoretic mobility are caused mainly by different amounts of sialic acid residues, coupled to the same protein backbone.

Acid Phosphatase↗