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Biomedical subjects

H Keller

Publications and source records attributed to H Keller.

At least 199 records · Page 11Linked to original sources
PubMed1989

Alpha-amylase determination with the Reflotron reagent carrier system: use of whole blood, plasma, and serum, and effect of isoenzymes.

In the Reflotron Amylase dry-reagent carrier system (Boehringer Mannheim GmbH) a new substrate is used for determining total amylase (EC 3.2.1.1) activity:indolyl-alpha-D-maltoheptaoside. The procedure shows low imprecision (median CV less than 3.2%), and results for sera, plasma, and capillary and venous blood (y) correlate well with those of a conventional alpha-amylase method involving p-nitrophenyl (PNP)-maltoheptaoside substrate (x) (for 209 blood samples: y = 0.981x + 9.7; r = 0.994). Correlation was also excellent with a method involving maltotetraose as substrate (r = 0.987). Attachment of an indoxyl residue rather than a PNP group to the maltoheptaoside did not affect the substrate response to pancreatic or salivary isoenzyme activity. Therefore, the relative proportion of these isoenzymes did not affect the correlation between the Reflotron Amylase reagent carrier and the alpha-amylase PNP-maltoheptaoside method. With a reaction time of less than 3 min, this system is especially suitable for amylase determination in situations where a prompt result is required.

Humans↗
PubMed1988

Effects of long-term treatment with 120 mg of sustained-release isosorbide dinitrate and 60 mg of sustained-release nifedipine on myocardial perfusion.

Forty patients with coronary artery disease and scintigraphically proven myocardial ischemia were randomized into 2 groups receiving 4 weeks of treatment with either 120 mg of isosorbide dinitrate (ISDN) release or 60 mg of nifedipine release. Control exercise testing and myocardial scintigraphy were continued until anginal pains occurred, and repeated at identical individual workloads at the end of the 4 weeks of drug therapy. Myocardial scintigrams were evaluated by quantitative recording of counts in 60 segments/frame. Twenty patients in the ISDN group (group I) exhibited 47 significantly ischemic areas. The remaining 20 patients (group II), treated with nifedipine, had 50 ischemic areas before therapy. In the ischemic areas in group I, there was a mean difference of 30.9% between counts at rest and during exercise in the pretreatment period, and a difference of 18.1% after therapy (39.0%). In group II, the pretreatment difference was 28.8%, decreasing to 20.6% after therapy (17.8%). Both groups of patients were subsequently subdivided into 3 subsets: (1) significantly improved perfusion, (2) significant worsening, and (3) unchanged myocardial perfusion. Group I had 59.5% of areas with significant improvement and 10.6% of areas with significant worsening. In 29.7% of the areas, the findings were unchanged. Group II had improvement in 40% of areas, of significantly worsened areas in 6%, and unchanged areas in 54%, in both groups myocardial ischemia was reduced by therapy, but ISDN improved myocardial perfusion to a considerably greater extent than did nifedipine.

Adult↗
PubMed1988

Investigation of the performance of the ES 600 Enzymun-Test system. A multicentre study.

The ES 600 sample-selective multibatch analyser was subjected to a multicentre evaluation in six laboratories in accordance with ECCLS guide-lines. During the 3-month trial, five Enzymun-Test diagnostics (T4, TBG, Digoxin, CEA and TSH)1) were measured at 25 degrees C. The study yielded the following results: 1. The within-series and between-series precision were very good, with mean CV's of approx. 3% and 7% respectively. 2. Recovery of the target values for three control sera was in the range +/- 5%. 3. A trend in measurements did not occur in any of the methods investigated (for series of over 240 determinations). 4. Comparison of the results with those obtained on the ES 22 Enzymun-Test system showed good agreement. 5. Within the measuring range defined by the standards, no deviations could be ascertained upon dilution of the samples. 6. Total carry-over in the instrument was below 0.05%. From studies with instruments from the first production series, it became evident that modifications were necessary to improve the reliability. A follow-up measuring programme confirmed a clear improvement in reliability and a reduction in the imprecision, particularly for results from series to series.

Carcinoembryonic Antigen↗
PubMed1988

One-point recalibration of heterogeneous enzyme immunoassays with non-linear calibration curves.

We have investigated one-point recalibration of heterogeneous enzyme immunoassays involving nonlinear calibration curves. By using a factor determined from a single standard we updated calibration curves obtained earlier by means of multiple-point determination. The prerequisite for this method is a reproducible working procedure, i.e., as ensured by a fully mechanized system. In our investigations with Enzymun-Test system ES 600 (Boehringer Mannheim) we determined alpha 1-fetoprotein, carcinoembryonic antigen, digoxin, ferritin, thyroxin-binding globulin, triiodothyronine, and thyroxin in human serum pools over a period of two weeks with both full calibration and one-point recalibration. Comparisons of the results thereby obtained show that the means of the concentrations and the CVs for the alternative calibration procedures differed negligibly, even if we used reagents exposed to different temperatures for different periods of time. With the one-point recalibration procedure presented here, therefore, one can considerably reduce the time and effort spent on calibration.

Calibration↗
PubMed1987

[Recurrent meningitis in familial deficiency of the 8th component of the complement system].

An 18-year-old man suffered from recurrent bacterial meningitis. Investigation of the complement system revealed deficiency of the 8th complement component (C8) in the patient and his sister. Genetic defects of the terminal complement components C5 to C8 predispose to Neisseria infections, probably due to a lack in bacteriolytic activity. It is to be noted that 1 year ago the patient had been hospitalized for a culture-proved pneumococcal meningitis.

Adolescent↗
PubMed1987

Human rabies immunoglobulin assayed by the rapid fluorescent focus inhibition test suppresses active rabies immunization.

The rabies antibody content of each of ten lots of human rabies immunoglobulin was titrated by both the mouse neutralization test and the rapid fluorescent focus inhibition test. The two tests did not give comparable results, the antibody titres obtained by the mouse neutralization test being 1.4-9.6 times higher than those obtained by the rapid fluorescent focus inhibition test. This titre difference was associated with a consistently lower antibody response in human volunteers who had received post-exposure rabies vaccine treatment which included the administration of RIG assayed by the RFFIT.

Adult↗
PubMed1987

Comparison of preoperative sonography with intraoperative findings in congenital hypertrophic pyloric stenosis.

In 17 infants with hypertrophic pyloric stenosis, the pyloric diameter was measured preoperatively by ultrasound. The mean pyloric diameter was 15.12 +/- 2.11 mm (mean +/- SD), range 11 to 19 mm. During pyloromyotomy, the hypertrophic pylorus was precisely measured craniocaudally and dorsoventrally, and measurements were obtained concerning muscular thickness and length of the pylorus. The preoperative and intraoperative measurements were subsequently compared. Differences of 0.76 +/- 1.68 mm and 1.24 +/- 2.04 mm were found for the dorsoventral and craniocaudal diameters, respectively. The intraoperative measurements were consistently greater than the sonographic findings. The length of the pylorus averaged 22.0 +/- 2.66 mm, the muscular thickness 6.53 +/- 1.68 mm, respectively. This prospective study confirms the diagnostic value of sonography in congenital hypertrophic pyloric stenosis.

Female↗