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Biomedical subjects

J Herrmann

Publications and source records attributed to J Herrmann.

At least 127 records · Page 7Linked to original sources
PubMed1976

[Measurement of thyroxine binding globulin by competitive ligand binding assay (CLBA) (author's transl)].

The competitive ligand binding assay (CLBA) first described by Chopra et al. ((1972) J. Clin. Endocrinol. Metab. 35, 565-573) is a convenient routine method for the accurate measurement of thyroxine binding globulin in large numbers of serum samples. The assay is based on the partition of a constant quantity of radiolabelled T3 between a fixed quantity of rabbit T3 antibodies and the thyroxine binding globulin of the serum, after prior removal of T3 and T4 from the serum with an anion exchange resin (Amberlite IRA 400). In euthyroid subjects serum thyroxine binding globulin was 25.5 +/- 5.0 mg/1, in hyperthyroid patients thyroxine binding globulin was significantly decreased to 13.0 +/- 4.0 mg/1 and was significantly increased in hypothyroid patients to 36.8 +/- 6.2 mg/1 as well as in pregnant women to 41.3 +/- 6.2 mg/1. No difference was found between normal subjects and young women taking contraceptive pills with low oestrogen content. There were significant negative correlations between the thyroxine binding globulin in serum on the one hand side and the free T4-and free T3-fraction on the other. The low thyroxine binding globulin estimates in hyperthyroid patients increased gradually to normal during treatment with thyroid blocking drugs, the elevated thyroxine binding globulin in hypothyroid patients decreased to normal during treatment with thyroid hormones. The competitive ligand binding assay used here seems to be convenient as a routine method for the precise and reproducible measurement of thyroxine binding globulin in serum.

Animals↗
PubMed1976

[New methods for evaluation and analysis of organoleptic qualities of foods and for calculation of changes. 9. Dependence of irradiation flavor of apple juice and concentrate on the gamma radiation dose].

Various authors have defined organoleptically the concept "cooking flavour" for heat-treated apple juice and concentrate. In a similar way, the "irradiation flavour" caused by gamma radiation is defined in the present paper. It has been found that the irradiation flavour is attributable to low-boiling substances which appear already in the first fraction if the modified MICKO distillation is performed. Tetrahydrofuran (THF) has been identified as the key substance in irradiation flavour. As further evidence may be quoted the similarity of the intensity of off-flavour which was observed also by gas chromatography at the same times of retention, and the removal of the irradiation flavour by means of a THF-specific agent (mercury acetate). In connection with THF solutions added to non-irradiated apple juice, the authors employed the technique of "subjective olfactometry", using the "absolute value scale", to establish mathematical correlations between the intensity of irradiation flavour and the concentration of off-flavour products in apple juice or concentrate. The dependence of the intensity of irradiation flavour on the THF concentration and the gamma radiation dose, respectively, obeyed an exponential function. Thus, it has been possible to calculate the amounts of THF formed by radiation doses varying from 0.64 to 2.55 Mrad. Furthermore, the authors determined the minimum radiation dose for 12% apple juice and for 67% apple concentrate at which the irradiation flavour is first perceived (treshold of perception).

Cobalt Radioisotopes↗
PubMed1976

[New methods for analysis and evaluation of sensory qualities of foods and calculation of changes. 10. Quantitative titrimetric determination of irradiation flavor in apple juice and concentrate and its dependence on radiation dosage].

Irradiation flavour in apple juice and concentrate which is mainly attributable, according to our previous studies, to tetrahydrofuran (THF) that may be quantitatively determined by means of the so-called mercury acetate method. This is based on the fact that the amount of a 4% solution of mercury acetate needed for removing the THF odour is proportional to the THF concentration. Using this method, the amounts of THF produced by various gamma radiation doses (varying from 0.64 to 2.55 Mrad) could be determined titrimetrically. Calculations showed that the THF concentration increases linearly with the radiation dose. Thus, the minimum radiation doses at which the irradiation flavour is first perceived (threshold of perception) may be calculated readily. The mercury acetate method is also a model case of the use of subjective olfactometry for the quantitative determination of flavour key substances in foods so far as they may be quantitatively determined by means of chemical reactions since the endpoint of titration is controlled by the sense of smell.

Chemical Phenomena↗
PubMed1976

Delayed mutation as a cause of retinoblastoma: application to genetic counseling.

The genealogic and genetic data on retinoblastoma were reviewed and interpreted according to the model of delayed mutation; then applications of the model to specific situations in genetic counseling were considered. Patients with multiple congenital abnormalities and systemic chromosome aberrations are regarded as belonging to a different category of retinoblastoma cases than the more common patients without such abnormalities. The model of delayed mutation is considered for the latter group of patients. According to the model, mutation at the retinoblastoma locus can be delayed or complete and can occur during meiotic or mitotic cell division. Genotypically, three clases of individuals can be identified in retinoblastoma families: homozygous normal, heterozygous for the premutated allele, and heterozygous for the (fully) mutated allele; the other possible combinations of individuals have apparently not been observed. There is to date no evidence to suggest incomplete penetrance of the mutant allele, but 14% of individuals who have the mutant gene are "only" unilaterally affected. Carriers produce normal, affected and carrier offspring in the empiric proportion of, respectively, 54.5%, 36.4% and 9.1%. Most difficulties in genetic counseling arise because affected individuals may have inherited the premutated or the mutated allele and because unaffected individuals may have inherited the normal or the premutated allele. These aspects were considered for individuals presenting as sporadic-unilateral, sporadic-bilateral, familial-unilateral and familial-bilateral cases, and the empiric risk figures for various situations were quoted from the literature.

Alleles↗
PubMed1975

[Excessive peripheral conversion of thyroxine (T4) to triiodothyronine (T3) in the pathogenesis of T3-hyperthyroidism (author's transl)].

In a 41-year-old woman and a 3-year-old girl, both of them with T3-thyrotoxicosis, serum levels of total and free T4 and T3 were measured serially during anti-thyroid drug treatment. Attempts to substitute thyroxine during the antithyroid treatment had to be interrupted because the patients became hyperthyroid again with excessive increases in total and free serum T3, even when concentrations of total and free T4 were brought to subnormal levels. The increased conversion of administered thyroxine ceased later on and higher amounts of oral T4 were tolerated after one year of treatment. In both patients there was an extremely low serum T4/T3 ratio, differing in this respect significantly from six other patients with T3-thyrotoxicosis and 41 patients with "conventional" T3/T4-hyperthyroidism. It is concluded that, in patients with T3-thyrotoxicosis due to excessive peripheral T4 to T3 conversion, substitution during antithyroid drug treatment should be either with very low doses of thyroxine or with triiodothyronine in divided daily doses. In such cases the level of serum T3 represents the most reliable biochemical measurement for the control of treatment, serum T4 levels being irrelevant.

Adult↗
PubMed1975

[The effect of synthetic somatostatin in normal and acromegalic males].

The synthetic linear tetradekapeptide somatostatin (growth-hormone release inhibitory hormone: GHRIH) inhibits the liberation of growth hormone in normal persons in the insulin hypoglycaemia test without influencing the rise of cortisol and prolactin, while the concentrations of LH, FSH and TSH remain unchanged. In patients with florid acromegaly there occurs during administration of GHRIH a marked fall in the raised STH level without influencing the basal level of the other anterior-pituitary hormones. As a further effect there is suppression of the insulin level. The somatostatin at present available has a very short biological half-life and in its present form is, therefore, without therapeutic importance.

Acromegaly↗
PubMed1975

Serum triiodothyronine 7-15 years after fractionated low dose radioiodine therapy of thyrotoxicosis.

In 189 of 334 patients, who had been treated with fractionated doses of radioiodine for Graves' disease 7-15 years ago, the serum concentrations of triiodothyronine have been estimated in additition to the following parameters: Protein bound 127-iodine (PB-127-I), free thyroxine index, cholesterol- and TSH-level in serum, tendon reflex time and clinical index according to Billewitz et al. (1969). In forty-one of the 189 sera the free T4 (AFT4) and free T3 (AFT3) concentrations were measured as well. The following hormonal and clinical patterns were observed: (1) Euthyroidism, with all parameters within the normal range in 148 patients (equals 78-4%). (2) Hypothyroidism with low serum T3, PBI, AFT4, AFT3 and elevated TSH six subjects (equals 3-2%). (3) Persistent hyperthyroidism with increased thyroid hormone concentrations and low TSH in seven cases (equals 3-7%). (4) In twenty-eight clinically euthyroid patients (equals 14-8%) TSH was elevated with normal PBI and AFT4. Twenty of these subjects had a low normal T3 and in nine the T3 was clearly in the hypothyroid range (40 plus or minus 12 mug/dl). (5) The constellation of normal T3, low T4 and elevated TSH, which has been frequently found after radioiodine therapy, has been seen in only moderate form in ten cases.

Adult↗
PubMed1975

Thyroid function and triiodothyronine and thyroxine kinetics in rabbits immunized with thyroid hormones.

Neck-uptake studies, thyroid scintiscans and triiodothyronine (T4)-kinetic studies were performed in normal rabbits and in animals producing antibodies against thyroid hormones. In immunized animals the radioiodide uptake and turnover were increased 3-fold and 6-17-fold, respectively. The thyroid glands were found to be enlarged scintigraphically and showed a denser tracer distribution pattern. T3 and T4 kinetic data were obtained from 5 rabbits immunized with T3 (ABT3), 4 immunized with T4 (ABT4) and from 5 controls. In T3 immunized animals total T3 in the serum rose from 86 to 59 000 ng/100 ml, in T4 immunized rabbits total T4 increased from 2.5 to 53.8 mug/100 ml. The fundamental principles of regulation were similar in both T3 and T4 immunized rabbits: There were enormous decreases in the total distribution spaces (TDS) as well as in the fractional turnover rates (k), resulting in markedly decreased metabolic clearance rates (MCR). The fall in T3-MCR was directly proportional to the T3 binding activity of the sera. However, striking differences between the respective alterations of T3 and T4 kinetic data were obtained in the immunized animals: T3-MCR fell about 70-fold in ABT3, whereas T4-MCR was diminished 15-fold in T4 immunized rabbits. In both groups of immunized animals T3-TDS decreased more than the T3 fractional turnover, whereas T4-TDS was less affected than k T4. The T3 production rates (PR) were increased 10-fold in ABT3 and 5-fold in ABT4, whereas the increases in T4-PR were of only moderate degree both in ABT3 and ABT4. Using presently available radiochemical methods in metabolic status of immunized rabbits could not be definitely assessed: "clinically" the animals were euthyroid. However, the dialyzable fraction in the serum of both T3 and T4 did not decrease proportionately to the enormous increase in total hormone concentration, so the free hormone concentrations were elevated over the normal. The results of the calculations of the cellular hormonal T3- and T4-clearance were more consistent with a euthyroid state: In ABT4 the cellular metabolism of both hormones was not different from the normal; in ABT3 a 1.7-fold increase in the cellular clearance of T3 was accompanied by a significant decrease of that in T4.

Animals↗
PubMed1975

[Calculation of thermal protein changes in food with heat conduction. Determination of reaction rate and activation heat].

The velocity constant k of protein changes is commonly determined by heating as abruptly as possible to a given temperature for various periods. Its dependence on temperature or activation heat is deduced from the k value determinations at different temperatures, using the ARRHENIUS diagram. In contrast to this, the authors determined the k and E values in a temperature field for a constant reaction time. This is done directly in the foodstuff which is introduced (in ball form) into a bath of constant temperature. In case of foodstuffs with mere heat conduction, there are in the interior innumerable spherical shells subjected to the same thermal stress which increases from within towards the exterior. Thermal protein changes (such as the thermal coagulation of egg white and muscle proteins and the formation of metmyochromogen) which can be visualized directly or, in case of enzymatic denaturation, indirectly by colour reactions, using the presence-absence method, may be observed if the ball is cut in half. This procedure (termed "change-over method" by the authors) permits to calculate the unknown k and E values from the radius of the visible inner circle. (This applied also to cylindrical forms.) Since this method allows to estimate approximately these reaction kinetic constants directly in the foodstuff under conditions encountered in practice, it is in many cases better suited for simulating, calculating, or optimizing desirable or undesirable protein changes occurring during thermal processing than the mere model experiment with abrupt heating which does not reproduce the changes in the reaction medium occuring during the slow increase or decrease in temperature.

Dietary Proteins↗