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Biomedical subjects

R Kremer

Publications and source records attributed to R Kremer.

100 records · Page 6Linked to original sources
PubMedDate not supplied

Studies of the effects of 1,25-dihydroxyvitamin D on skeletal and calcium homeostasis and on inhibition of tumor cell growth.

Vitamin D, parathyroid hormone (PTH), and parathyroid hormone-related peptide (PTHrP) are major regulators of calcium metabolism and vitamin D can also reduce the growth of normal cells and tumor cells. PTHrP and PTH act via a common membrane receptor (PTHR). The mouse PTHR is regulated by a kidney-selective upstream promoter P(1) and ubiquitous downstream promoter P(2). In vitro and in vivo 1,25(OH)(2)D can inhibit PTHR expression in bone but not cartilage by downregulating transcription via P(2). Gene transcription of PTHrP per se can also be downregulated by 1,25(OH)(2)D and by low calcemic vitamin D analogs. This inhibitory effect may reduce the hypercalcemia caused by overproduction of PTHrP by tumor cells. In a malignant keratinoctye cell line, phosphorylation of the retinoid X receptor alpha occurs through the activated Ras-MAP kinase pathway and results in attenuated trans-activation by the vitamin D receptor, its heterodimeric partner. This decreases the growth-inhibitory efficacy of 1,25(OH)(2)D. Studies of the capacity of vitamin D to alter PTHrP production and action and of its anti-proliferative effects can, therefore, shed important light on basic mechanisms controlling these events, and may also have major implications for clinical medicine and therapeutics.

Animals↗
PubMedDate not supplied

Idiopathic hypertrophic subaortic stenosis: long-term surgical results.

The results of surgery in 21 patients with I.H.S.S. are reported. Dyspnea, angina pectoris and syncope were the most common symptoms in decreasing frequency. Before the operation, 5 patients were in New York Heart Association's functional class II, 10 in class III and 6 in class IV. The mean resting peak systolic pressure gradient was 66 mm Hg in 20 patients and mean left ventricular end-diastolic pressure was 14 mm Hg in 19 patients. The ventriculoseptomyectomy accomplished through a transaortic approach is the procedure of choice. The operative mortality rate was 14% (3 of 21 patients). There were 2 late deaths from congestive heart failure. Any sudden death did not occur. The remaining 16 patients have been followed up for a mean of 75 months (range 12 months to 11 years), 11 patients are in functional class I, 4 in class II and 1 in class III. Complete left-bundle-branch block occurred in 3 patients. Our study with a long post-operative follow-up period, documents that surgery results in good to excellent alleviation of symptoms in survivors. The elevated pre-operative left ventricular end-diastolic pressure has a significantly poor prognosis. We currently recommend surgery for the symptomatic patients who have not responded to medical therapy, not late in the symptomatic course of the disease.

Adolescent↗
PubMedDate not supplied

[Silent myocardial ischemia. Psychosomatic viewpoint].

Recent research has shown that myocardial ischemia, even in a severe form, may occur without anginal symptoms. The pathophysiology of such silent ischemic episodes and cardiac ischemic pain in general remain unclear. The aim of this study is to investigate the possible interaction between undercomplaining and denial mechanisms with pain acceptance, in order to see if such psychological factors may be of value in understanding the clinical difference between silent and painful ischemia in coronary artery diseased patients. The psychosomatic approach appears to be relevant for the study of cardiac pain and a new understanding of silent myocardial ischemia is thus proposed and discussed.

Angina Pectoris↗
PubMedDate not supplied

[Simultaneous radiocompetitive assay for 25 hydroxyvitamin D and 24, 25 dihydroxyvitamin D in human serum (author's transl)].

A specific competitive protein binding assay for 25 hydroxy-vitamin D and 24, 25 dihydroxyvitamin D in human serum has been developed. It includes a chromatographic step on a Sephadex LH 20 column to specifically separate the metabolites. The average value was for 25 hydroxyvitamin D 11.9 +/- 6.6 Ng/ml (mean +/- SD) and for 24, 25 dihydroxyvitamin D 6.85 +/- 3.29 ng/ml in ten normal subjects sampled in autumn. In hepatic insufficiencies the mean level of 25 hydroxyvitamin D was lower and the mean level of 24, 25 dihydroxyvitamin D was higher than in normal subjects. In patients with renal insufficiency the 25 hydroxyvitamin D levels were normal and the 24, 25 dihydroxyvitamin D levels were low but not suppressed. The two sterols were also determined in some patients with idiopathic hypercalciuria.

Binding, Competitive↗
PubMedDate not supplied

Surgical treatment of mitral stenosis.

Analysis of 239 patients who underwent a commissurotomy for mitral stenosis (196 closed technique, 43 open technique). Total operative mortality was 2%. Long term follow-up is illustrated by an actuarial survival curve and long-term functional results are studied up to 15 years after operations. It allows the authors to consider commissurotomy alone as a good palliative procedure with good functional results in the majority of cases. However, in view of the collected data, they now elect to restudy all the patients 6 years after the primary correction and to perform a heart catheterization to consider appropriate reoperation in some cases.

Adult↗
PubMedDate not supplied

Tricuspid valve surgery.

Our purpose was to study the long-term results of the tricuspid valve replacement. It is obvious that tricuspid annuloplasty (Kay, De Vega) has its place in the treatment of functional tricuspid insufficiency that accompanies mitral or mitral and aortic valve disease. The Carpentier ring appears justified for some cases. However tricuspid valve replacement can be the operation of choice for some patients. Our study demonstrated that the Björk-Shiley and Starr-Edwards prostheses remain good substitutes in tricuspid valve surgery and that the long-term results are better than it was anticipated a decade ago.

Adult↗