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Biomedical subjects

L B Jaques

Publications and source records attributed to L B Jaques.

At least 37 records · Page 2Linked to original sources
PubMed1980

Occurrence of heparin and multisulfated chondroitins in the rat gastrointestinal tract and effect of fat feeding.

Rats were fed glucose solution for 3 days and killed without fasting. Examination of the crude polysaccharides extracted from the gastrointestinal tract by electrophoresis on the micro scale and using critical electrolyte concentration and bacterial enzymes showed three types of sulfated mucopolysaccharides were present. These were identified as heparitins, multisulfated chondroitins, and heparins. The heparin resembled a macromolecular heparin of moderate molecular weight. Following oil feeding, only the heparitins and multisulfated chondroitins were present in the small intestine, and no heparin was found. With fasting for 12 h after glucose feeding, the amount of the heparin fraction in the small intestine was reduced. The results obtained demonstrate the presence of a heparin in the rat small intestine which is responsive to changes in diet.

Animals↗
PubMed1979

Anticoagulant activity and operative blood loss after intrapulmonary heparin.

The safety and efficacy of heparin given by the intrapulmonary route are further assessed in this study. A single dose of heparin (2000 units/kg) was given by intratracheal instillation in dogs and measurements of plasma heparin concentration, whole blood clotting time and partial thromboplastin time made at intervals for 48 h. These values rose progressively and in parallel for 7 h and remained elevated for 48 h. A series of operations was performed on dogs within 3 h of a single dose of intrapulmonary heparin (1500 units/kg). Operations involving minimal dissection (small bowel resection) and extensive dissection (resection of muscle) were performed in two separate groups. Within each group the animals were randomly given heparin or saline. In the limited dissection group there were no differences in operative blood loss, wound healing, or sequential haemoglobin and haematocrit measurements. In the group subjected to muscle resection there was increased postoperative wound drainage and a slightly greater fall in haemoglobin and haematocrit in those given heparin. It is concluded that heparin is absorbed from the lung causing significant changes in coagulation parameters. Even with the relatively high dose of 1500 units/kg, operations were performed with minimal hazard. Intrapulmonary heparin may have important clinical applications after further investigation.

Animals↗
PubMed1979

Cellular control of heparin in blood.

Many investigators have observed the uptake of exogenous heparin by cells of the reticuloendothelial system (R.E.S.). When heparin is administered by the intravenous, intramuscular, subcutaneous, intraperitoneal and intratracheal routes the anticoagulant response observed is of varying magnitude. This has led us to examine the literature for evidence of a distribution of heparin between the cellular and blood compartments. A re-evaluation of such evidence has provided a new perspective on the pharmacokinetics of heparin. This is presented here in the cellular pool concept which is based on the premise that there exists in the body a pool of cells which takes up a portion of the administered heparin, stores it and later releases it to the circulation. This concept provides a rational explanation for the different types of anticoagulant response obtained with different modes of administration.

Biopharmaceutics↗
PubMed1979

A novel method to separate the layers of the intestine.

By applying cellulose acetate paper to the lumenal and serosal surface of the intestine of rats, we have divided the intestine into three layers. Examining the layers histologically, we have shown that most of the villi are removed from the mucosal surface, ther serosa alone is removed from the serosal surface, and muscle layers. This appears to provide a rapid procedure for separation of the layers of the intestine for histological and biochemical studies.

Animals↗
PubMed1979

Heparin via the lung.

Only recently has it been realized that heparin is absorbed when administered into the lung. Im mice, rats, dogs and humans a large dose of intrapulmonary heparin has been shown to cause a moderate degree of hypocoagulability lasting from 48 hours to 14 days depending on the species. This study is part of an ongoing program investigating the effects of the intrapulmonary administration of heparin. Heparin, 1500 units/kg body weight was instilled into the lung in a group of 12 dogs and an equal volume of saline was given in a control group of 10 dogs. Various hemodynamic and metabolic measurements were made at intervals. As expected there was a prolonged moderate increase in clotting time, but no significant effects from intrapulmonary administration of heparin were demonstrated by any of the other measurements. Much work has yet to be done before intrapulmonary heparin can be used clinically but it has potential importance in the management of thromboembolic disease.

Animals↗
PubMed1977

The mast cell/heparin paradox.

Purified heparin extracted from tissues rich in mast cells remains the ideal rapid anticoagulant in clinical practice. Nevertheless, there are grounds for doubting that an injection of commercial heparin corresponds to the release of heparin-containing granules from the mast cells. The metachromatic granule contains much more than heparin--chondroitins, heparitins, histamine (in some species 5-hydroxytryptamine also), and a variety of enzymes. Shed granules, released by trauma of any kind, are ingested by connective-tissue phagocytes and are digested. Commercial heparin, on the other hand, is taken up by cells of the reticuloendothelial system and is stored there. This apparent paradox can be resolved by conceding that the mast cell is primarily concerned with the connective tissue, as Ehrlich saw it a century ago, and that, within these broad limits, it can express itself in a variety of ways.

Animals↗