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Biomedical subjects

R Lang

Publications and source records attributed to R Lang.

At least 253 records · Page 14Linked to original sources
PubMed1980

The importance of circulating 1,25-dihydroxyvitamin D in the pathogenesis of hypercalciuria and renal-stone formation in primary hyperparathyroidism.

Fifty patients with primary hyperparathyroidism were studied with an oral calcium-tolerance test, measurements of plasma levels of vitamin D metabolites, and determination of calcium excretion on both a low-normal (400 mg) and high-normal (1000 mg) calcium intake. There were strong positive correlations between plasma levels of 1,25-dihydroxyvitamin D (1,25(OH)2D) and both the calciuric response to the calcium-tolerance test (r = +0.75, P less than 0.001) and calcium excretion on the 1000-mg calcium diet (r = +0.65, P less than 0.001). The patients were classified into two subpopulations: 30 patients showed hyperabsorption with the calcium-tolerance test, striking hypercalciuria, marked elevations in plasma 1,25(OH)2D, and a high incidence (19 of 30 patients) of renal stones; 20 patients had a normal response to the tolerance test, normocalciuria, normal or high-normal plasma 1,25(OH)2D, and a low incidence of stones (three of 20 patients). The findings emphasize the importance of circulating 1,25(OH)2D in the pathogenesis of hypercalciuria and stone formation in primary hyperparathyroidism.

Calcium↗
PubMed1980

1,25(OH)2D3 is not the only D metabolite involved in the pathogenesis of osteomalacia.

Three patients are described in whom there was no simple correlation between plasma 1,25(OH)2D3 concentration and the occurrence of osteomalacia. One patient had severe osteomalacia with high plasma 1,25(OH)2D3 and normal mineral ion product; the second had a normal mineral ion product and no evidence of osteomalacia even though plasma 1,25(OH)2D3 was undetectable; and the third had osteomalacia, low plasma 1,25(OH)2D3 and a reduced mineral ion product. In considering these data in the light of presently available information, it is concluded that osteomalacia can occur as a consequence of a lack of a vitamin D metabolite other than 1,25(OH)2D3, or a consequence of a reduced mineral ion product, but not as a consequence of 1,25(OH)2D3 lack if the mineral ion product is normally maintained and other D metabolites are present. However, a deficiency of 1,25(OH)2D3 normally leads to a reduction in the mineral ion product hence 1,25(OH)2D3 deficiency may play a role in the development of certain forms of osteomalacia.

Adult↗
PubMed1980

5' flanking region of immunoglobulin heavy chain constant region genes displays length heterogeneity in germlines of inbred mouse strains.

Genomic Southern blotting analysis reveals that a 5' flanking DNA sequence located 1.5-2.0 kb upstream from the C mu and C alpha genes undergoes extensive length variation in the germlines of inbred and wild mice. In addition, genomic clones of the BALB/c C mu gene undergo deletion events during their propagation in Charon 4A when maintained in RecA+ bacterial strains. These deletion events occur between the JH cluster and the C mu gene and approximately 2.0 kb 5' of the C alpha gene, and may encompass several kb of DNA. Deletion events are capable of yielding a group of C mu clones which differ in size by units of 100-200 bp. The site of length variation in the mouse germline corresponds to the location of these cloning-derived deletion events, suggesting that both phenomena are reflections of intrinsic genetic properties of these Ig gene 5' flanking sequences.

Animals↗
PubMed1980

Assessment of bone mass in the radius by computed tomography.

A reproducible method for quantitative analysis of computed tomographic cross-sections of the distal radius of patients with various metabolic bone diseases is described. A statistically significant correlation between the CT measurements in the radius and quantitative histomorphometric measurement of the trabecular bone volume of corresponding transilial bone biopsies is demonstrated. Selected longitudinal studies are presented to demonstrate the possible clinical applications of this type of CT analysis.

Adult↗
PubMed1980

Balance of noradrenaline and sodium during chronic beta-receptor blockade in patients with essential hypertension.

The antihypertensive action of chronic beta-blockade, with simultaneous reduction of beta-receptor activity at the medullary, cardiac and renal levels, is complex. An integrated explanation is offered by stressing the importance of the whole-body balance between sodium and noradrenaline. Evidence was provided in an eleven week lasting study in patients with essential hypertension, where chronic beta-blockade was performed by increasing doses of Pindolol (10--20 mg/die). While urinary sodium and noradrenaline showed only small changes, the correlation between blood pressure and the sodium/noradrenaline quotient reversed significantly. The altered correlation is interpreted as the common result of the different hypotensive actions of chronic beta-blockade, with special regard to the renal component. Thus, pressure normalisation in essential hypertension during chronic beta-blockade is achieved by an adjustment of the imbalance between whole-body sodium and whole-body noradrenaline.

Adrenergic beta-Antagonists↗
PubMed1980

Bizarre urologic manifestations of pancreas carcinoma.

A 62-year-old patient presented with fever and abdominal pain. Urinary retention and bilateral hydronephrosis were caused by bladder malfunction due to infiltration of the bladder wall by metastases from a carcinoma of the head of the pancreas. Both ureters were free. A previous choledochoduodenostomy prevented the development of jaundice.

Carcinoma↗
PubMed1980

Urinary tract infections in pediatric practice. A comparative study of three diagnostic tools: dip-slides, bacterioscopy and leucocyturia.

1,261 fresh urine specimens of patients of a pediatric office were examined by optical microscope and cultured on dip-slides (Urotube). 132 pathological bacteriurias, representing 95 certain episodes of UTI, served as reference material. The bacteriuria, leucocyturia and bacterioscopy were analysed by means of four validity tests: sensitivity test, predictive value of negative test, specificity test, and predictive value of positive test. The comparison shows that bacterioscopy is as valuable as dip-slides, provided that (a) only the clearly or highly positive bacterioscopies, or (b) the associated bacterioscopy and leucocyturia--but only double negative or double positive--be considered.

Bacteriuria↗
PubMed1979

[Hemodynamic and humoral changes during administration of a sympathomimetic and a sympatholytic drug with special notes on the regulation of renin release (author's transl)].

Studies in normal volunteers documented the positive inotropic effects of Etilefrin-HCL, a direct sympathomimetic drug, with increases of systolic blood pressure, renal blood flow and glomerular filtration rate. Sodium and potassium excretion as well as serum potassium decreased. After an additional injection of Metoprolol, a beta 1-sympatholytic drug, blood pressure, renal blood flow and glomerular filtration rate normalized, whereas electrolyte excretion decreased further. Renin release was decreased during administration of Etilefrin as well as during combined Etilefrin and Metoprolol application. Reziprocal to changes of blood pressure, plasma norepinephrine concentration decreased during Etilefrin and increased during combined administration of Etilefrin and Metoprolol. The results lead to the following interpretation: Changes of blood pressure and renal hemodynamics are mediated by beta 1-adrenergic effects of Etilefrin, whereas the electrolyte excretion is influenced by beta 2-adrenergic effects. Renin release seems to be influenced by beta 1 as well as beta 2-adrenergic receptors.

Adult↗
PubMed1979

Sympathetic activity and transcendental meditation.

Ten male advanced meditators and ten male long-term meditators subjected themselves four times to slight physical exercise following a period of rest, meditation or reading. Daily urine excretions of catecholamines and VMA were determined in both groups. On the experimental days 4-hour urine specimens, one before and one after the experiments, were again collected for analysis. During the experiments blood pressure and heart rate were measured continuously and blood samples were taken for plasma catecholamine levels immediately before and after the physical exercise. Daily catecholamine and VMA excretions showed to be higher in advanced meditators. During the experiments the pattern of noradrenaline, adrenaline and VMA excretions were different in both groups, long-term meditators showing a higher adrenaline excretion after exercise. After the resting period there was in both groups a similar increase of plasma catecholamine levels during exercise. However, after meditation the advanced meditators showed a significant increase in plasma noradrenaline and no further increase in plasma noradrenaline level during the following physical exercise. Also after the reading period differences between both groups in plasma catecholamine levels during exercise could be observed. In advanced meditators heart rate reduction after meditation was about 9% and diastolic blood pressure was slightly raised. The preceding conditions of rest, meditation or reading had a significant different influence on the behaviour of heart rate and blood pressure during the following physical exercise and this pattern was different for both groups.

Adult↗
PubMed1979

Differential and integral corticosteroid feedback effects on ACTH secretion in hypoadrenocorticism.

Recent work suggests the existence of a dual corticosteroid feedback mechanism of stress-induced ACTH secretion in the rat. This possibility led us to study the kinetics of suppression of ACTH levels by corticosteroid administration in patients with nonstress ACTH hypersecretion secondary to hypoadrenocorticism. Cortisol was administered according to different protocols, which were chosen to provide extreme variations of the input signal. By this means, two phases of suppression of ACTH levels could be differentiated. A first decrease occurred without latency whenever, and as long as, plasma cortisol levels were rising. There was a linear regression between the logarithm of the increments in cortisol concentrations and the decrease in ACTH levels per minute (r = 0.951) (differential or rate-sensitive feedback mechanism). Neither the absolute doses of cortisol, nor plasma cortisol concentrations were closely correlated with the degree of suppression of ACTH by this rapid mechanism. A second decrease in ACTH levels began congruent with30 min after corticosteroid administration. In this case there was a significant linear regression between the degree of inhibition of ACTH levels and the cortisol doses (r = 0.997) (integral or dose-sensitive feedback mechanism). The dose-sensitive feedback effects of dexamethasone were less than might have been predicted from its relative anti-inflammatory potency. No rate-sensitive effects were seen with dexamethasone doses of 1.0 or 1.25 mg.

Adrenal Cortex Hormones↗