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Biomedical subjects

H L Frank

Publications and source records attributed to H L Frank.

11 recordsLinked to original sources

Effects of vitamin K and oral anticoagulants on urinary calcium excretion.

In a subgroup of postmenopausal women vitamin K induced a decrease of the urinary calcium loss. This effect was significant (P < 0.0001) in the so-called fast losers of calcium (calcium/creatinine ratio > 0.5). To find out whether vitamin K antagonists would have an opposite effect, a study was started among 141 persons on long-term oral anticoagulant therapy. In this population the number of fast losers was recorded, and compared to that in a group of age- and sex-matched non-treated controls. Notably in young men the fraction of fast losers was significantly higher in the anticoagulant-treated group than in the control group (25 v 0%, P < 0.02). Differences between treated and nontreated groups may also be found in other markers for calcium and bone metabolism, notably in serum osteocalcin concentration and in urinary hydroxyproline excretion. The conclusion of our study is that oral anticoagulant treatment must be regarded as a potential risk factor for a high loss of urinary calcium.

Adult

The value of an expert system in performing clinical drug trials.

An expert system has been designed to assist the cardiologist in determining whether patients can be included in clinical trials. This system contains knowledge on inclusion and exclusion criteria for six drug trials, and has been validated in 100 randomly selected patients. In 97 cases, the expert system and the cardiologist made an identical classification; in the remaining three cases, the patient was incorrectly classified by the physician. The system will also optimize the order in which questions are asked in order to minimize the time required to decide on inclusion or exclusion.

Angina, Unstable

The mechanism of action of oral anticoagulants and its consequences for the practice of oral anticoagulation.

A short review on the discovery of the relation between vitamin K and the synthesis of clotting factors and on the development of anticoagulant therapy is given. The procoagulant activity induced by vitamin K resides in the postribosomal modification of N-terminal glutamic acids in gamma-COOH glutamic acids. The mode of action of oral anticoagulants is explained. The concentration-effect relations and the choice of an oral anticoagulant is discussed.

Administration, Oral

The contribution of alpha1-antitrypsin to the total antitrypsin activity of human serum. A study of two phenotype PI OO individuals.

Comparison of the levels of alpha1-AT, alpha2-M, inter alpha-AT, C1 inactivator and antiplasmin and global antitrypsin activity in a group of normal phenotype PI MM individuals, a group of normal individuals with phenotypes with intermediate alpha1 AT activities and alpha2-AT-deficient persons show that alpha1-AT contributes more than 90 percent of the total antitrypsin activity of normal plasma. AT III and fast reacting antiplasmin are shown to contribute to the remaining activity. It can be assumed that due to test conditions the antitrypsin activity of alpha2-M is not assessed. C1 inactivator and inter alpha1-AT do not contribute to a perceptible extent to the overall antitrypsin activity estimated according to the method of Eriksson (Eriksson, S. (1965) Acta Med. Scand. 177, 1).

Adult

The influence of glycerol on the Ca flux in the isolated perfused rat heart.

Perfusion of the isolated rat heart with a fluid containing 800mM glycerol in addition to its normal constituents causes a contraction height decrease of about 50%. A change to normal perfusion fluid causes a period of contracture to occur. After this period the heart is perfectly viable. Mechanical and osmotic effects could be ruled out as possible causes. No gross disturbances were seen in the electron micrographs. An effect on intermediary metabolism is equally unlikely. Presumably, we must seek the explanation in a direct effect of the glycerol on the Ca++ fluxes across the cellular and intracellular membranes.

Animals