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Biomedical subjects

A Jung

Publications and source records attributed to A Jung.

At least 163 records · Page 9Linked to original sources
PubMed1982

Model for parathyroid hormone secretion and metabolism in calves.

A model for parathyroid gland response to differing calcium and magnesium concentrations is proposed based on direct determinations of parathyroid hormone (PTH) secretion rate. A proportional control seems adequate for physiological variations of calcium and magnesium levels. At extreme hypocalcemia, nonlinearities are observed: a model involving the depletion of a storage compartment is proposed, the size of which is calculated. PTH distribution was studied in another group of animals; sampling was made from the saphenous artery and the thoracic duct. Concentrations of plasma and lymph-intact PTH and carboxy-terminal fragments were determined by means of two different radioimmunoassays. The analysis of the results leads to the formulation of a five-compartment model, which shows that the metabolism of intact PTH is only partly due to the formation of carboxy-terminal fragments, most being directly secreted or catabolized. Linking these models for secretion and distribution of PTH, simulation studies were undertaken and compared with published data. This model is then discussed in comparison with previous work concerning other polypeptide hormones.

Animals↗
PubMed1982

Parathyroid gland response to epinephrine: a rate-sensitivity mechanism.

A model for parathyroid gland response to an epinephrine infusion is proposed. It is based on direct measurements of the parathyroid hormone (PTH) secretion rate as measured directly after cannulation of the venous drainage of single superior parathyroid glands of calves. When epinephrine was infused into a jugular vein, a large increase of PTH secretion rate was observed at the beginning of the infusion. The PTH secretion rate thereafter fell, but it was still significantly above the control rate. At the end of the epinephrine infusion a sharp decrease was observed when the infusion was terminated. These observations are consistent with a rate-sensitive control mechanism. Calculation of the parameters yielded a model, which was then linked with a kinetic model for PTH distribution. Simulation studies were undertaken to predict plasma PTH concentration in response to an epinephrine infusion. Good agreement was found between predicted results and previously published work. The role of this rate-sensitive mechanism in the parathyroid gland is discussed.

Animals↗
PubMed1981

[Diphosphonates in the treatment of bone metastases].

The diphosphonates are a group of phosphate compounds which inhibit the growth and dissolution of apatite crystals. These drugs have similar biological effects on bone by inhibiting the osteoclasts, and are also active in preventing pathological calcifications. The diphosphonates have been used successfully in various bone diseases and are now currently used for bone scanning. They are also considered one of the best treatments for Paget's disease. Several experiments in vitro and in vivo have suggested that the diphosphonates are active against bone metastases. Clinical trials have been undertaken and have shown that these compounds are active against malignant hypercalcemia. Further, they may delay the extension of bone destruction due to malignancy.

Animals↗
PubMed1981

Parenteral diphosphonates for treating malignant hypercalcemia.

Two diphosphonates, EHDP (disodium etidronate, or ethanehydroxy-diphosphonate) and Cl2MDP (disodium clodronate, or dichloromethylene-diphosphonate) were injected in various doses in six patients with one or multiple episodes of malignant hypercalcemia. All patients responded well to the drugs after a delay period of two to seven days. The tolerance of the drugs was excellent. EHDP, and especially Cl2MDP, are promising agents for treating hypercalcemia and inhibiting bone resorption in malignant disorders.

Aged↗
PubMed1981

[Treatment of Paget's disease of bone: diphosphonates or calcitonin?].

During the past 6 years 16 patients suffering from Paget's disease of bone have been treated and regularly followed up in our department. 10 of these patients have received etidronate (ethane-hydroxy-diphosphonate), 4 others have received synthetic human calcitonin and the last 2 have received both treatments, first successively then simultaneously. Under either therapy satisfactory clinical and biological results have been observed (diminution of pain and decreased levels of serum alkaline phosphatase and hydroxyprolinuria). Etidronate has been more efficient in reducing biological parameters, whereas calcitonin has produced a faster symptomatic response. On the basis of these observations the present principles for treatment of Paget's disease are discussed.

Aged↗
PubMed1981

Multiple mRNAs are generated from the chicken lysozyme gene.

We have determined the DNA sequence of a 770 bp Pst 1 fragment containing 450 nucleotides of the 5' flanking region of the chicken lysozyme gene. S1-nuclease mapping was performed to localize the 5' end of nuclear RNA containing lysozyme-specific sequences and of the mRNA. We present evidence that the 5' noncoding region of the chicken lysozyme mRNA is heterogeneous in length. The 5' termini of the different nRNAs map 29, 31 and 53 nucleotides upstream from their common initiation codon. The 5' ends of lysozyme-specific nuclear RNAs map at positions similar to that of the mRNA. AT-rich regions and sequences similar to the E. coli RNA polymerase recognition sequence are found around 30 and 70 nucleotides upstream from each of these 5' termini. The AT-rich regions differ, however, from the canonical Goldberg-Hogness box in that they do not contain the extremely conserved TATA sequence motif. Sequence comparison at the 5' end of the lysozyme, conalbumin and ovalbumin genes reveals only one region of partial homology, 140 nucleotides upstream from the mRNA start sites.

Animals↗
PubMed1981

Inhibition by two diphosphonates of bone lysis in tumor-conditioned media.

In order to test the effect of diphosphonates in inhibiting bone lysis induced by human tumors, neonatal mouse calvaria are cultured in sterile conditions in different media. Osteolysis is estimated by the amount of 45Ca released from bone to medium, the mice being given injections of 45Ca on their day of birth. An increased bone lysis is observed when calvaria are incubated in the same medium conditioned from cultured tumor fragments. This effect is significantly decreased when the mice have been treated with either ethanehydroxydiphosphonate or dichloromethylenediphosphonate. These experiments represent a first step in estimating the potential effects of different drugs on malignant osteolysis.

Animals↗
PubMed1980

[Vitamin D intoxication].

Vitamin D intoxication is not so rare as is usually thought. Three cases of vitamin D poisoning are described, in each of which the indication for treating the patients was reasonable but the dosage was not adapted as it should have been. All three patients recovered within a few days. The mechanism of these intoxications is discussed and emphasis is placed on the prevention of such accidents.

Adult↗
PubMed1980

[Treatment of hypercalcemia of tumoral origin with two diphosphonates].

Two diphosphonates, EHDP (disodium etidronate, or ethane-hydroxy-diphosphonate) and Cl2MDP (disodium clodronate, or dichloromethylene-diphosphonate) were injected in various doses in 8 patients who had had one or more episodes of malignant hypercalcemia. All patients responded well to the drugs after a time lapse of 2-10 days. Tolerance of the drugs was excellent. EHDP, and especially Cl2MDP, are promising agents for the treatment of hypercalcemia and the inhibition of bone resorption in malignant disorders.

Adult↗
PubMed1980

Exons encode functional and structural units of chicken lysozyme.

The nucleotide sequence was determined for the chicken egg white lysozyme mRNA and for the exons of the gene together with their flanking intron regions. The exon pattern is to some degree related to the structural subdivision of the final protein product. However, the relationship of exons to functional units of the enzyme is better established. Exon 2 codes for amino acids 28-82, which include the catalytically active residues and a cluster of amino acids which bind rings C, D, E, and F of the oligosaccharide substrate. Exon 3 codes for amino acids 82-108, which give additional substrate specificity, determine the cleavage frame for the alternating N-acetylglucosamine/N-acetylmuramic acid chain, and increase the catalytic efficiency of the active center. Exons 1 and 4, respectively, code for translational signal sequences on the mRNA, for the signal peptide of prelysozyme, and for the amino- and carboxy-terminal regions of the enzyme. These regions increase the stability of the molecule but are not directly involved in the catalytic function.

Animals↗
PubMed1980

[Studies of X-ray morphology of the heart contour in ischemic heart disease as seen in dorsoventral X-ray photography of the thorax in the basis of coronarographic findings (author's transl)].

Cardiovascular diseases hold a place of considerable importance in national health schemes and various screening methods have been devised to determine and to control such diseases. One of the methods is based on the use of thorax photofluorographs obtained from regular nation-wide X-ray examinations. The ischemic heart disease is a significant group among cardiovascular diseases and it appears that dorsoventral photofluorography is an insufficient means for its recognition. For 250 subjects examined by intracardial methods for suspected ischemic heart disease, a retrospective study of dorsoventral thorax photofluorographs was performed along the lines of the classification by Richter and Böck. The results show that in about 75 percent of the cases of ischemic heart disease associated with serious lesions of the coronary vessels, no signs of changes in the heart contour were seen in photofluorographs of the thorax. It is concluded that the evaluation of chestfilm is an inadequate approach as far as the ischemic heart disease group is concerned within photofluorographic screening programmes for cardiovascular diseases.

Cardiac Catheterization↗
PubMed1980

[Transthoracic lung-biopsy in diffuse lung diseases (author's transl)].

A report is given about 360 percutaneous transthoracic lung biopsies in diffuse affections of the lung framework. By means of a good cooperation between skilled lung physician and experienced lung pathologist it was able to get a definitive diagnosis in 88.3% of the cases. The expense concerning this diagnostic procedure is small. As for complications there occurred pneumothoraces (15.8%), lung haemorrhage (5.3%) and haemothorax (1 case).

Biopsy↗
PubMed1979

[Effect of 2 phosphonates on the osteolysis induced by tumor extracts].

An in-vitro model is proposed to test the potential effect of diphosphonates in treatment or preventing bone metastases. This model involves culturing of neonatal mice calvaria in sterile conditions in an appropriate medium and measuring 45Ca release from bone to medium, the mice being injected with 45Ca on the day of birth. Tumour extracts added to the medium usually increase the bone lysis; this effect is significantly decreased when the mice have been treated with either ethane-hydroxy-diphosphonate (EHDP) or dichloromethylene-diphosphonate (Cl2MDP). These experiments represent a first step in a group of experiments with a view to clinical trials in cases of bone metastases.

Animals↗
PubMed1979

[is there an osteomalacia component in femur neck fractures?].

In 29 patients with fractures of the femoral neck (group A) and 22 patients operated on for osteoarthritis of the hip (group) B), plasma levels of 25-hydroxycholecalciferol (25-OH-D3) were compared with the results of histological bone tests. A third group of 19 patients at the Geriatric hospital served as a control in this age group for 25-OH-D3 values (group C). The average level of 25-OH-D3 was 9.64 +/- 5.8 micrograms/l in group A and 13.25 +/- 7.6 micrograms/l in group B. This difference is not significant. On the other hand, the difference between groups B and C (9.31 +/- 4.04) is significant (2 p less than 0.05). Evaluation of the histological sections did not reveal evidence of osteomalacia. Generally speaking, the levels of plasma 25-OH-D3 in these patients were low, but without signs of osteomalacia on histological evaluation.

Aged↗
PubMed1979

Free-flow electrophoresis for the separation of malaria infected and uninfected mouse erythrocytes and for the isolation of free parasites (Plasmodium vinckei): a new rapid technique for the liberation of malaria parasites from their host cells.

After aggregation of erythrocytes from malaria infected mice, the parasites (Plasmodium vinckei) could be set free using gentle mechanical forces. The mixture of freed parasites, infected and non-infected erythrocytes, and membraneous material was separated by free-flow electrophoresis. The free parasites produced were very pure and infectious. Morphological and enzymatic data on the separated fractions are presented. Free-flow electrophoresis also allowed the separation of infected and uninfected erythrocytes.

Animals↗