Modified antithrombin III levels during normal pregnancy and relationship with prothrombin fragment F1 + 2 and thrombin-antithrombin complexes

This case report describes a pregnancy in a patient with autosomal-dominant adult polycystic kidney disease and congenital hepatic fibrosis, a very rare and problematic combination. In particular, hypertension and renal dysfunction caused problems during this pregnancy. Peritoneal dialysis became necessary.     

Estrogen increases low-density lipoprotein receptor-independent catabolism of apolipoprotein B in hyperlipidemic rabbits

Estrogen has been reported to increase the catabolism of low-density lipoprotein (LDL) apolipoprotein (apo) B by increasing LDL receptor activity. To determine the effect of estrogen on LDL receptor-independent pathways, paired turnover studies of native LDL and chemically modified LDL (methyl-LDL) were performed before and during estrogen administration in female New Zealand rabbits consuming a diet containing 0.5% (wt/wt) cholesterol. Rabbits were matched by plasma cholesterol concentration and assigned randomly to receive estrogen (estradiol cypionate 0.5 mg/kg/wk) or placebo. The residence time of both the native LDL apo B tracer and the methyl-LDL apo B tracer in plasma was decreased by estrogen but not by placebo. Multicompartmental modeling of the paired, double-labeled turnover studies indicated that an increase in fractional catabolic rate (FCR) of the fast-turnover pool, a kinetically distinct LDL subpopulation in plasma, accounted for the observed decrease in residence time in plasma for both tracers. These data support the hypothesis that, in addition to any effect on the LDL receptor, estrogen promotes the activity of LDL receptor-independent pathways.     

Comparative pharmacology of site directed antithrombin agents. Implication in drug development

Beside the direct inhibition of thrombin and its regulatory functions, many of the newer antithrombin agents produce several additional effects, unrelated to their anticoagulant actions. Synthetic peptide inhibitors are capable of producing fibrinolytic compromise by virtue of their actions on fibrinolytic enzymes such as t-PA, plasmin, urokinase and protein Ca. In addition, the low molecular weight arginine-containing peptides are also known to produce hemodynamic and hemostatic deficits. The designs of the ongoing clinical trials are largely empirical because of the non-availability of valid pharmacologic and toxicologic data on thrombin inhibitors. In contrast to heparin, none of the thrombin inhibitors produce endogenous release of tissue factor pathway inhibitor (TFPI) in the experimental and clinical settings. These observations suggest that beside the direct inhibition of thrombin, these agents also produce multiple additional effects that can significantly contribute to their pharmacologic and toxicologic profile.     

Sequelae of diathermocoagulation of cerebellar arteries and veins in normal rabbits and rabbits sensitized to brain antigen

Electrocauterization of an artery or a vein on the surface of the posterior lobe of the cerebellum may cause no focal changes in the bed of the occluded vessel, or result in varying severity and extension of lesion of the posterior cerebellar lobe. In occluding an artery a focus of complete necrosis or oedema is formed in its bed, while in occluding avein a focus of oedema is formed that may be accompanied by erythrocytic extravasation. In the group of animals sensitized with brain antigens a tendency towards oedema enhancement, and a vascular permeability increase is noted, neuronal changes are more frequent at a distance from the occluded vessel's basin. However, the importance of sensitization is, as a rule, masked by individual peculiarities of the collateral supply or venous return in the bed of the occluded vessel.     

The renal handling of delta-aminolevulinic acid in normal and lead-poisoning rabbits

A radioimmunoassay (RIA) procedure has been developed for measurement of testosterone in male plasma after ether:chloroform (4:1) extraction of the plasma sample without resorting to chromatography. The highly specific anti-testosterone serum was generated from both rabbits and sheep immunized with 15beta-carboxyethylmercapto-testosterone-BSA conjugate. The synthesis of 15beta-carboxyethylmercaptotestosterone and the preparation of its BSA conjugate are described. The high affinity (Ka=2.38 X 10(9) liters/mole) antiserum binds 50% of 50 picograms of tritiated testosterone at working dilutions of 1:100,000 to 1:200,000. Both 5alpha and 5beta-dihydrotestosterone compounds exhibited less than 2% cross-reaction. The only other steroids that showed minor cross-reaction were 11beta-hydroxytestosterone (3.8%), progesterone (2.1%), corticosterone (1.6%), and deoxycorticosterone (7.7%).     

Pulmonary catabolism of interleukin 6 evaluated by lung perfusion of normal and smoker rats

Cytokines such as interleukin 6 are involved in the pulmonary inflammation arising as a result of smoking. By use of isolated and perfused lung preparations we have evaluated the role of the lungs in the catabolism of human recombinant interleukin 6 both in normal rats and in rats subjected to an acute cigarette smoking episode. When interleukin 6 was incorporated into the lung perfusion medium, neither control nor smoke-exposed rat lungs cleared the cytokine and only 0.1 +/- 0.2% of the total dose was recovered in the bronchoalveolar lavage fluid. When, on the other hand, the same amount of interleukin 6 was instilled into the bronchoalveolar tree, concentrations of the cytokine in the perfusate increased progressively so that after 3 h up to 70.1 +/- 9.8% and 40.9 +/- 22.5% of the administered dose, as measured by immunoenzymatic test, had been transferred from the bronchial lumen to the perfusion medium of either control or smoker rat lungs, respectively, indicating significantly (P < or = 0.05) different behaviour of the cytokine in the two experimental groups. Total recoveries of the administered interleukin 6 evaluated in smoke-exposed rat lungs were 55.3 +/- 23.2%, significantly lower than those for control rat lungs (83.9 +/- 11%). Determination of biological activity gave values always lower than those measured by immunoenzymatic test, indicating loss of biological activity during the transalveolar transit. It appears that the transfer of interleukin 6, especially in smokers, is almost exclusively unidirectional, from the alveolar space to the plasmatic pool with degradation during the transalveolar passage.     

Retinoid permeability and uptake in corneas of normal and vitamin A-deficient rabbits

In vitro perfusion of corneas of normal and vitamin A-deficient rabbits provided a model in which to study the pharmacokinetics of corneal permeability and uptake of retinoic acid and retinol. The permeability coefficients of retinoic acid and retinol were 1.49 x 10(-5) and 0.61 x 10(-5) cm/s, respectively. Removal of the corneal epithelium did not affect the permeability of these lipid-soluble retinoids; however, diffusion through xerophthalmic, vitamin A-deficient corneas was significantly reduced. The corneal uptake of retinoic acid and retinol was reduced by 50% on removal of the epithelium, was nonspecific, and was not affected by xerophthalmia. High-performance liquid chromatography indicated that these retinoids were not metabolized during diffusion through the cornea. These results show that topical application of retinoids is a rational approach to the treatment of such corneal diseases as xerophthalmia and epithelial defects.     

Enhanced endothelial tissue factor but normal thrombomodulin in endotoxin-treated rabbits

Exposure of cultured endothelial cells to bacterial endotoxin induces an enhancement of cell procoagulant activity (PCA) and a simultaneous reduction of thrombomodulin activity (TM). We evaluated the effect of endotoxin on the expression of both endothelial PCA and TM in vivo, in rabbits. Animals were given a single i.v. injection of endotoxin (E. coli 0111:B4 LPS, W, 10-200 micrograms/kg); the thoracic aorta was harvested after 2 or 4 hours and placed in an ad hoc device to expose the endothelial surface only. Endotoxin treatment resulted in a dose-dependent increase of endothelial PCA (p < 0.001, at 100 micrograms/kg or more), which was totally dependent on factor VII and thus identified as tissue factor. In contrast, endothelial TM activity, as measured by the rate of thrombin-induced protein C activation, was similar in control and endotoxemic rabbits, even when the animals were given two injections (50 micrograms/kg, 24 h apart), or a continuous infusion (40 micrograms/kg/h during 4 hours) of endotoxin. To explore the effect of endotoxin on TM activity at the microcirculation level, we measured the extent of protein C activation in vivo, induced by a continuous infusion of low doses of thrombin (1 NIH U/kg/min for 60 min). Again, endotoxin administration was not associated with significant changes in TM-dependent protein C activation, as assessed by the anticoagulant activity present in a barium citrate plasma eluate obtained at the end of thrombin infusion. Although reduction of TM during persistent endotoxemia cannot be definitively excluded, our data support a major role of endothelial PCA in LPS-induced coagulative changes.     

Clinical utility of prothrombin fragment 1+2, thrombin antithrombin III complexes and D-dimer measurements in the diagnosis of deep vein thrombosis following total hip replacement

BACKGROUND: Measurements of prothrombin fragment 1+2 (F1+2), thrombin antithrombin III complexes (TAT) and D-dimer plasma levels have been proposed as non-invasive screening tests to exclude postoperative deep venous thrombosis (DVT). We investigated the diagnostic efficacy of these coagulation activation markers to rule out postoperative DVT in patients undergoing hip surgery under antithrombotic prophylaxis. METHODS: In this substudy of a randomized double-blind thrombosis prophylaxis trial comparing three doses of desirudin (10, 15 or 20 mg b.i.d.) with unfractionated heparin (5000 IU t.i.d.) we used ELISA procedures to measure F1+2, TAT and D-dimer in 159 patients undergoing total hip replacement at baseline (day 0) and on postoperative days 1, 3 and 6. Bilateral venography was performed in all cases 8-11 days after surgery. RESULTS: For the F1+2 assay sensitivity ranged from 73 to 83% in the three postoperative days investigated, and negative predictive value (NPV) from 68 to 74%. For TAT and D-dimer sensitivity ranged from 71 to 73% and from 71 to 83% and NPV from 61 to 65% and from 61 to 74% respectively. INTERPRETATION: In terms of sensitivity and NPV F1+2 and D-dimer are equivalent and are superior to TAT. However, their accuracy is too low to rule out the presence of DVT after hip surgery under antithrombotic prophylaxis.     

Modulating effect of sodium diethyldithiocarbamate on neutrophils in normal, febrile and cold-stressed rabbits

The studies were conducted on normal, febrile and cold-stressed rabbits. Fever was induced by a single intravenous injection of 1 micrograms/kg of E. coli lipopolysaccharide (LPS). The animals were submerged in ice-water for 20 s and then were kept at -15 degrees C for approx. 8 min., until their body temperature dropped by 3 degrees C. Sodium diethyldithiocarbamate (DTC) was injected i.v. to normal, febrile and cold-stressed rabbits, in a single dose of 2 or 20 mg/kg. The effect of DTC on body temperature, the number of neutrophils in blood, phagocytic activity of neutrophils and their ability to reduce nitroblue tetrazolium (NBT) were evaluated. It was found that DTC administered in a dose of 2 or 20 mg/kg did not affect the body temperature of rabbits. In normal rabbits, DTC did not change the number of neutrophils, but increased their phagocytic activity and ability to reduce NBT. In febrile rabbits, DTC depending on the dose, shortened the stimulating effect of LPS on neutrophil ability to reduce NBT but enhanced and prolonged the effect of pyrogen on neutrophil phagocytic activity. The rabbits treated with DTC prior to hypothermia exhibited shorter neutrophilia resulting from cold stress. In addition, DTC administered to the rabbits before their exposure to cold stress proved to be a partial or even total protection against the decrease in NBT reducing ability and phagocytic activity of blood neutrophils.     

Hereditary antithrombin deficiency and pregnancy. Pregnancy course in six women with known hereditary antithrombin deficiency

Inherited antithrombin (AT) deficiency is a major cause of venous thromboembolism, especially in relation to surgery and pregnancy. We present six AT deficient pregnant women, who successfully delivered seven babies at the Department of Gynaecology/Obstetrics, Aalborg Hospital. From conception, or if possible prior to conception, the women were treated with unfractionated (UFH) or low molecular weight heparin (LMWH) throughout the pregnancy. If the pregnancy was without complication, AT substitution was only used at delivery and for approximately a week post-partum, when warfarin treatment was re-instituted.     

Role of endothelial cell mitosis in transendothelial transport of low density lipoprotein in hypercholesterolemic and normal rabbits

From January 1992 to August 1993, 59 calcaneal fractures in 48 patients were treated. Thirty-three fractures in 31 patients were displaced intra-articular fractures and were treated with open reduction and internal fixation through an extensile lateral approach with the Galveston plate (Smith and Nephew, Richards, Memphis, TN). Complete radiographs and CT scans were available for 32 of the fractures. The CT scan classification of Sanders was used. The distribution of the fractures was: IIA, N = 17; IIB, N = 2; IIC, N = 2; IIIAB, N = 7; IIIAC, N = 2; IV, N = 2. Sixteen (50%) had calcaneocuboid joint involvement. Preoperative and postoperative radiographic measurements of Bohler's angle, Gissane's angle, talocalcaneal angle, and Achilles tendon fulcrum distance were made. Clinical follow-up on 23 fractures in 22 patients at an average of 21 months is presented. Seventy percent of the patients have no pain or only occasional pain not requiring medication. Using the Maryland Foot Score for assessment, 78% of the patients had a good or excellent result. The Galveston plate was useful for maintaining reduction of intra-articular calcaneus fractures treated operatively and provided results comparable to other reported series.     

Regulation of thrombosis and hemostasis by antithrombin

An ELISA has been set up for quantifying mouse monoclonal antibodies in culture supernatant. The assay includes rabbit anti-mouse IgG antibodies chromatographycally purified. This preparation was used as coating and as conjugated antibodies in the ELISA. The assay can detect IgG1 with sensitivity of 0.2 ng/mL, IgG2a (0.85 ng/mL), IgG2b (0.13 ng/mL), and IgG3 (3.19 ng/mL) in culture supernatants. The effective working range was from subnanogram per mL quantities to 30 ng/mL by using a computer statistical program. Variation coefficient of ELISA was below 7%. Correlation estimates with a similar ELISA using commercial reagents were performed for each mouse antibody subclass. The assay was able to detect the four mouse monoclonal antibody subclasses in pure human serum as compared with the same ELISA using commercial antibodies. A 24-h pharmacokinetic profile of 1 patient treated with an IgG2a monoclonal antibody is presented.     

Comparative analysis of smooth muscle isoactin gene expression in normal and neoplastic tissues

Monoclonal antibodies derived from the actin multigene family are routinely used as an adjunct to morphologic diagnoses of smooth muscle tumors. Northern blot analysis was performed on 60 surgical resections utilizing isoactin-specific cDNAs. A comparison of this analysis to immunohistochemical studies demonstrated that actin-specific monoclonal antibodies represent reliable markers of the smooth muscle lineage. Smooth muscle neoplasms showed a unique pattern of gamma-smooth muscle isoactin gene expression, providing a potentially valuable molecular adjunct to the morphologic diagnosis of uterine smooth muscle tumors.     

The effects of starvation, glucose infusion, and normal feeding, on muscle protein synthesis and catabolism in the newborn guinea pig

We determined the effects of feeding, starvation, and glucose infusion after starvation in newborn guinea pigs. We determined the rate of 14C-leucine incorporation into skeletal muscle (KS) as a measure of muscle protein synthesis and the rate of excretion of 3-methylhistidine as a measure of muscle myofibrillar protein catabolism (Kc). Fed newborns, who were in positive nitrogen balance, had the highest Ks and lowest Kc, while starved newborns had the lowest Ks and highest Kc. Infusing glucose after starvation decreased net protein catabolism and Kc, but did not increase Ks. The magnitude of change of Kc in response to starvation and glucose infusion was much greater than Ks. Changes in catabolic rate may influence net muscle protein balance to a greater degree than changes in synthetic rate.