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Biomedical subjects

R Haeckel

Publications and source records attributed to R Haeckel.

At least 91 records · Page 5Linked to original sources
PubMed1979

Hydrazonopropionic acids, a class of hypoglycemic substances. 1. Hypoglycemic effect of 2-(phenylethylhydrazono)- and 2-(2-cyclohexyl-ethylhydrazono)-propionic acid.

The two hydrazone-compounds 2-(phenylethylhydrazono)-propionic acid (PEHP) and 2-(2-cyclohexyl-ethylhydrazono)-propionic acid (CHEHP) significantly lowered the blood glucose level in several laboratory animals fasted 48 hours (guinea pigs, mice, hamsters and rats). In the guinea pig, PEHP produced a three times stronger hypoglycemic effect than phenelzine, its corresponding hydrazine. Conversely both hydrazono compounds decreased the monoamine oxidase activity much less, than phenelzine. CHEHP (145 mumol/kg) inhibited this enzyme by less than 14%. After oral administration both hydrazones (200 mumol/kg) also produced a distinct hypoglycemic effect. The blood glucose lowering properties of the two hydrazones were most manifest in fasted guinea pigs, diabetic mice and rats with streptozotozin diabetes.

Animals↗
PubMed1979

Monitoring of serum theophylline concentrations by a fully mechanized enzyme immunoassay (EMIT).

An evaluation of an enzyme immunoassay for the determination of theophylline in serum (EMIT, Syva Corp.) is presented. The EMIT assay was fully mechanized by the use of an Eppendorf analyzer 5010. The precision of this enzyme immunoassay was satisfactory (coefficients of variation from day to day ranged from 5--6%). The EMIT assay proved to be specific, rapid and easy to perform. A comparison of the results obtained by EMIT and ultraviolet spectrophotometry in a series of 100 patients showed a good correlation between both methods.

Cross Reactions↗
PubMed1979

Evaluation of enzyme immunoassays for determination of thyroxine (EMIT, ENZYMUN) and of thyroxine binding index.

An evaluation of enzyme immunoassays for determination of thyroxine in serum (EMIT ABA thyroxine assay, Syva Corp., ENZYMUN assay thyroxine, Boehringer Mannheim) and of thyroxine binding index (ENZYMUN assay TBI1), Boehringer Mannheim) is presented. The precision of the enzyme immunoassays was adequate (coefficients of variation ranged from day to day with EMIT from 3--11% and with ENZYMUN from 4--11%). Both assays are specific and easy to perform. About 20 unknown samples can be analyzed in duplicate by EMIT within 60 minutes and by ENZYMUN within 250 minutes. A comparison of the results obtained by enzyme immunoassays and radioimmunoassay in a series of about 100 patients showed a good correlation between both methods. The precision of the ENZYMUN TBI assay was adequate (coefficient of variation from day to day 4.9%) and the thyroxine/TBI-ratio correlated well with the thyroxine/TBG-ratio.

Humans↗
PubMed1979

Comparison of 9 methods for the determination of cholesterol.

Seven enzymatic procedures for the determination of cholesterol in serum were compared with the Liebermann-Burchard- and a gas-chromatographic method. Using a decision matrix all methods could be ranked according to reliability and practicability . With the exception of the cholesterol oxidase-coupled Kageyama principle and the Liebermann-Burchard procedure, all the other methods showed similar reliability.

Autoanalysis↗
PubMed1979

[Determination of thyroxine in serum by a heterogeneous enzyme immunoassay: results of a joint trial].

This paper describes the evaluation of a heterologous enzyme immunoassay for the determination of total thyroxine in serum by a group of seven clinical chemical laboratories. The test follows the principles of the enzyme linked immunosorbent assay (ELISA) and uses peroxidase as a marker. The evaluation of analytical reliability yielded the following results within the analytical range from 39 unto 322 nmol/l: 1. Within-batch precision ranged from 3.1 unto 10.4% (coefficient of variation) with single analyses. 2. Between-batch precision ranged from 3.7 unto 20.4% with single analyses. 3. Between-laboratories precision ranged from 5.4 unto 6.8%. 4. Pure thyroxine, added to serum or thyroxine-free serum, gave recoveries between 93 and 120%. 5. Analysis of control sera gave results essentially comparable to the assigned values based upon radioimmunoassays. 6. Analysis of 288 clinical sera gave slightly higher results by the enzyme immunoassay than by the analogous radioimmunoassay from the same manufacturer. 7. Comparison with other methods of analysis (radioimmunoassays, competitive protein ligand assays, hormonal iodine assay) yielded partly comparable, partly higher results. 8. Comparison with the homogenous enzyme immunoassay (EMIT) led to comparable results. 9. Interference due to hyperlipemia or hemolysis was not observed. 10. There might be an interference in hyperbilirubinaemic sera, due to an as yet unknown factor. With respect to practicability the ELISA-test compares favourably with the analogous solid phase radioimmunoassay. The main differences are the absence of radioactive material and a longer shelf-live of reagents. Following the manual procedure the time taken to perform the enzyme immunoassay is slightly longer than for the analogous radioimmunoassay.

Enzyme-Linked Immunosorbent Assay↗
PubMed1978

[The clinical significance of hyperuricemia for the prognosis of pregnancy toxemia].

This study demonstrates that uric acid serum levels are of importance in the prognosis of pregnancy complicated by hypertension. In early pregnancy the uric acid level probably is the most sensitive parameter to select the risk-prone pregnancies with EPH-gestosis to conduct the further course of pregnancy under medical care. Pregnant hypertensives with high uric acid levels develop more often retardation of the fetus, the incidence of eclampsia increases. In case of hypertension in pregnancy complicated by high uric acid levels careful monitoring and normalizing high blood pressure under medical observation improves the prognosis for fetus and mother.

Abortion, Spontaneous↗
PubMed1977

The influence of hydrazine, phenelzine and nialamide on gluconeogenesis and cell respiration in the perfused guinea-pig liver.

Hydrazine (2 mmol/l) and phenelzine (0.5 mmol/l), which are known to produce hypoglycaemia, inhibit glucose formation from lactate in the perfused guinea-pig liver. The hydrazone formed from pyruvate and phenelzine exerted the same effect at concentrations of only 0.05 mmol/l. It is suggested that the hydrazones are the substances which are effective. All these compounds inhibited pyruvate consumption and decreased CO2 production by the perfused liver which, togeteher with the pattern of hepatic metabolite concentrations, indicate that they diminish pyruvate metabolism. None of them influenced the activities in vitro of pyruvate carboxylase, phosphoenolpyruvate carboxykinase and pyruvate dehydrogenase. The hydrazone compound caused an increase of the ATP/ADP ration at lower concentrations and an opposite effect above 0.5 mmol/l. Nialamide, another hydrazine derivative, also reduced hepatic glucoeogenesis but led to a marked decrease in the hepatic ATP/ADP ratio and liver cell respiration accompanied by a rise in the 3-hydroxybutyrate/acetoacetate ratio.

Animals↗
PubMed1977

Drug screening by enzyme immunoassay (EMIT) and thin-layer chromatography (Drug Skreen).

Urine samples (n = 300) were examined for drugs by thin-layer chromatography ("Drug Skreen", Brinkmann Corp.) and by the "Enzyme Multiplied Immunoassay Technique" ("Emit", Syav Corp.). The results of both methods were compared for the detection of opiates, barbiturates and amphetamines. In more than 90% of the determinations identical results were obtained with both methods. About 10% of the results of the Emit barbiturate assay differed from those of thin-layer chromatography and therefore had to be further investigated by gas liquid chromatography. It could be demonstrated that the barbiturate determination by the Emit system correlated better with the results of gas liquid chromatography. From the results of this study it is suggested that thin-layer chromatography is used as a screening test, and to confirm positive results with other methods such as Emit. If the abuse of barbiturates or opiates is suspected the corresponding Emit test should also be performed, even in cases of a negative thin-layer chromatography screening. Confirmation with a third method such as gas liquid chromatography is necessary, if thin-layer chromatography and Emit lead to divergent results.

Amphetamines↗
PubMed1977

Determination of phenobarbital and phenytoin in serum by a mechanized enzyme immunoassay (EMIT) in comparison with a gas-liquid chromatographic method.

The antiepileptic drugs phenobarbital and phenytoin were determined in serum by enzyme immunoassay (Emit, Syva Corp.) and gas-liquid chromatography. The Emit assays were mechanized by the use of an Eppendorf analyzer 5010. The precision of the Emit system was sufficient (coefficient of variation within series 6-13% and from day to day 8-15% with various calibrators and control sera). Moreover the Emit method is rapid, specific and easy to perform. The procedure requires only 10 microliter of serum per determination. A disadvantage however is the high cost of the reagents. A comparison of the results obtained by Emit and gas-liquid chromatography in a series of about 50 patients showed a good correlation between both methods (correlation coefficient r = 0.968 for phenobarbital and 0.978 for phenytoin).

Child↗