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Biomedical subjects

A Burger

Publications and source records attributed to A Burger.

At least 109 records · Page 6Linked to original sources
PubMed1981

Organic mental syndrome and confusional states in Parkinson's disease. Relationship to computerized tomographic signs of cerebral atrophy.

Ninety-three patients with a diagnosis of Parkinson's disease, otherwise unselected, were specifically evaluated for organic mental syndrome (OMS) and other neurologic motor signs other than those referrable to extrapyramidal dysfunction; in addition, they had cranial computerized tomography (CT) to measure any structural changes in brain parenchyma. Cortical (sulci) atrophy and ventricular enlargement as CT signs of cerebral atrophy were correlated with different clinical patterns of the disease. An age-adjusted control population, with intact mentation, was similarly studied. The presence of classic OMS in a sizable segment of the usual parkinsonian population was invariably associated with CT signs of cerebral atrophy. Atrophic changes on CT scans, however, were not necessarily correlated with any intellectual dysfunction, or only weakly so, independent of age. The "typical" parkinsonian patients without evidence of OMS were indistinguishable from an age-adjusted control group with regard to structural changes in their scans. However, the parkinsonian patients with definite, permanent OMS and other focal neurologic deficit probably constitute a separate or distinct subset of the parkinsonian population, with a pathologic substrate more likely to be similar to that of the so-called Alzheimer-type dementias. Duration of the parkinsonian syndrome was not predictive of either mental status or scan findings, after adjustment for age as a factor.

Aged↗
PubMed1981

The effect of antipyrine, phenobarbitol and rifampicin on thyroid hormone metabolism in man.

The effect of three different live microsomal enzyme inducing drugs on thyroid hormone metabolism was investigated. Seven volunteers were randomly allocated in a crossover design to either antipyrine (1200 mg), phenobarbital (100 mg) or rifampicin (1200 mg) daily for 14 days. Before and after each treatment the following parameters of enzyme induction were measured: antipyrine clearance, gamma-glutamyltranspeptidase, d-glucaric acid and 6-beta-hydroxycortisol urinary excretion. In addition, thyroxine-binding globulin (TBG), T3-resin uptake (RT3U), thyroxine (T4), free thyroxine (FT4), triiodothyronine (T3), reverse T3 (rT3), and thyroid stimulating hormone were estimated. Following antipyrine and phenobarbital antipyrine clearance increased by about 45%, while with rifampicin an increase of 125% was observed. The indices of thyroid function did not change following phenobarbital and antipyrine, but after rifampicin T4, FT4 and rT3 decreased by about 14%, and T3 increased by 25%. In addition, the impact of rifampicin on the clearance of injected 125I-T4 was investigated in six additional volunteers by blocking thyroid iodine uptake. The 125I-T4 halflife decreased from 155 to 106 h and its clearance increased from 25 to 50 ml/h, while a fall in T4, FT4 and rT3 by about 40% and no rise but a decrease in T3 by 25% occurred. Therefore an increased clearance of T4 and rT3 but not of T3 seems likely following rifampicin, which might be due to enhanced hepatic metabolism and biliary excretion.

Adult↗
PubMed1981

[The influence of the polymorphism of the active substance on the properties of tablets. Part 3. Compressional behaviour of meprobamate (author's transl)].

Three polymorphic meprobamate-modifications (I, II, III) of different particle size were compressed without other ingredients on a hydraulic press under 30, 60, 120, and 240 N/mm2. The rather soft substance shows a high degree of densification and above ca. 60 N/mm2 also good consolidation properties. The void volumes of the compacts obey the equation of Kawakita and are increasing in all cases in the sequence I leads to III leads to II. The radial breaking strength generally decreases in the same succession and depends linearly on the logarithm of compaction pressure. It is noteworthy, that the modification with the highest density (I) has the highest plasticity and is also compacted most easily. Modification II which is slightly harder and has a density between modifications I and III, shows the greatest differences in the compaction behaviour, as compared to modification I. Its breaking strength is also increasing faster with compaction pressure than the other modifications.

Drug Compounding↗
PubMed1980

The nondeiodinative pathways of thyroxine metabolism: 3,5,3',5-tetraiodothyroacetic acid turnover in normal and fasting human subjects.

Complete turnover studies of T4, T3, rT3, and 3,5,3',5-tetriodothyroacetic acid (TA4) were carried out in normal subjects given T4 (0.2 mg, by mouth daily) by the integration method. When compared to the five fed controls, the four fasting subjects showed a decrease of mean T3 disposal from 41 to 18 micrograms/day, an increase of mean rT3 disposal from 49 to 61 micrograms/day. The mean serum TA4 concentration rose from 53 to 112 ng/dl, while the TA4 metabolic clearance remained unchanged. The fraction of T4 metabolized by deiodination changed from 79.0% to 77.5% in the fasting subjects as the fraction of T4 metabolized by deamination changed from 1.1% to 2.2%. Therefore, fasting induces a significant shunting of T4 away from T3 production into rT3 and TA4 production. However, oxidative deamination remains a minor metabolic pathway of T4 in man during both normal and fasting conditions. Given its low disposal rate and low biological potency, the increased TA4 production during fasting is probably not the inhibitory factor of TSH response to the lowered T3 production during fasting.

Adult↗
PubMed1979

[Clinical value of human thyroglobulin measurement].

A direct radioimmunoassay for human serum thyroglobulin (TG) has been developed. The lower limit of detection of the assay was 7.5 ng/ml. The serum values in normal subjects were between 0 and 44 ng/ml (n = 34, 21 female subjects, 13 male subjects). In 22 of the 34 subjects, TG was not detectable. The mean value of TG in a group of 19 subjects with multinodular goiter was 115.8 +/- 62.7 ng/ml (mean +/- SD). A group of 16 thyrotoxic individuals also had an elevated TG concentration (107 +/- 71 ng/ml). The serum TG levels in 6 patients with differentiated thyroid carcinoma with metastases were much more elevated than in any other clinical situation (3430 +/- 1100 ng/ml). In patients with thyroid cancer in clinical remission (n = 9), the TG levels were normal. In 2 patients with non-differentiated thyroid tumors, TG was not detectable. The major methodological problem in TG determination is the presence of anti-TG autoantibodies which may interfere with the radioimmunoassay.

Autoantibodies↗
PubMed1979

Thyroid hormones and the energetics of active sodium-potassium transport in mammalian skeletal muscles.

1. The steady-state heat production rate (E) of soleus muscles obtained from adult mice in various thyroid states was measured in a perfused microcalorimeter. The ouabain-suppressible fractions of E and 42K influx were compared and the energetic efficiency of active Na-K transport assessed. 2. Hypothyroidism with plasma thyroxine concentrations below 1 microgram/100 ml. was induced by pretreatment with 131I or perchlorate. In soleus muscles isolated from treated animals, mean E values were 25.1 +/- 0.7 and 24.2 +/- 0.5 mcal.g wet wt.-1.min-1 for the 131I and the perchlorate series respectively, i.e. about 30% lower than the control level (36.3 +/- 1.5 mcal.g wet wt.-1.min-1). Following triiodothyronine treatment, E was increased by about 45%. 3. In muscles from hypothyroid (131I and perchlorate series), euthyroid and hyperthyroid mice ouabain (10(-3) M) induced a rapid decrease in E of 1.6 +/- 0.1 and 1.4 +/- 0.1, 2.5 +/- 0.2, and 4.3 +/- 0.6 mcal.g wet wt.-1.min-1 respectively, i.e. between 6 and 8% of E. 4. In muscles obtained from hypothyroid, euthyroid and hyperthyroid mice, the ouabain-suppressible component of 42K influx was 0.17 +/- 0.04, 0.31 +/- 0.02 and 0.45 +/- 0.02 micromole. g wet wt.-1.min-1 respectively. Whereas the total number of ouabain binding sites varied appreciably with the thyroid status, the Na-K contents of soleus or diaphragm muscles showed no significant changes. 5. Notwithstanding the parallelism between the changes in basal E and ouabain-sensitive components of E and K influx with the thyroid status, it is concluded that active NA-K transport cannot be considered a primary effector of thyroid thermogenesis in intact mammalian skeletal muscle. The direct contribution of active NA-K transport to this thermogenesis was indeed small compared with the over-all cellular energy dissipation. 6. The minimum over-all energetic efficiency of the transport process in the intact muscles (30--35%) was not dependent on the thyroid status.

Animals↗
PubMed1978

Drug design and development. A realistic appraisal.

The discovery of new biologically-therapeutically active structures continues to depend on screening and on isolated observations of unexpected drug metabolites and drug activities. The selection of therapeutically improved and useful chemicals requires molecular modification. Refinements in intuitive and physiochemical methodology can provide shortcuts in random choices and permit extrapolations of some facets of activity with a variable degree of accuracy. The final decisions concerning the usefulness of a drug remain in the domain of experimental and clinical pharmacology.

Chemical Phenomena↗
PubMed1978

Effect of starvation on the production and peripheral metabolism of 3,3',5'-triiodothyronine in euthyroid obese subjects.

The effect of starvation on the peripheral metabolism of rT3 was evaluated in four obese euthyroid patients. During starvation, the serum rT3 concentration increased by 69% while the MCR of rT3 decreased in all four patients from control values of 96 +/- 23 (mean +/- SD) to 68 +/- 17 liters/70 kg . day, resulting in a slight increase in the mean production rate of rT3. These findings are in contrast to the marked decrease in T3 production rate associated with fasting, indicating that inner and outer ring deiodination of T4 can be varied independently.

Female↗