Burn and smoke inhalation-related multiple organ dysfunction is associated with a severe fall in the plasma concentration of antithrombin. Therefore the aim of the present study was to test the hypothesis that intravenous administration of recombinant human antithrombin in combination with aerosolized heparin will ameliorate acute lung injury in sheep exposed to cutaneous burn and smoke inhalation. Sheep were prepared operatively for study and, 7 days post-surgery, sheep were given a cutaneous burn (40% of total body surface area, third-degree burn) and insufflated with cotton smoke (48 breaths, <40 °C) under halothane anaesthesia. After injury, sheep were placed on a ventilator and resuscitated with Ringer's lactate solution. The animals were divided into three groups: sham group (non-injured and non-treated; n =6), saline group (injured and received saline; n =6) and rhAT.iv.+Hep group [injured and treated with rhAT (recombinant human antithrombin) and heparin; n =6]. In the rhAT.iv.+Hep group, rhAT was infused continuously for 48 h starting 1 h post-injury with a dose of 0.34 mg·h −1 ·kg −1 of body weight and heparin (10000 units) was aerosolized every 4 h starting at 1 h post-injury. The experiment lasted 48 h. Haemodynamics were stable in sham group, whereas the saline-treated sheep developed multiple signs of acute lung injury, including decreased pulmonary gas exchange, increased inspiratory pressures, extensive airway obstruction and increased pulmonary oedema. These pathological changes were associated with a severe fall in plasma antithrombin concentration, lung tissue accumulation of leucocytes and excessive production of NO. Treatment of injured sheep with anticoagulants attenuated all of the pulmonary pathophysiology observed. In conclusion, the results provide definitive evidence that anticoagulant therapy may be a novel and effective treatment tool in the management of burn patients with concomitant smoke inhalation injury.

The morphology of gastrocnemius muscles was examined in RFPs (renal failure patients) being treated using HD (haemodialysis) and CAPD (continuous ambulatory peritoneal dialysis). RFPs ( n =24) volunteered to participate in the present study. Twelve RFPs (five women and seven men; mean age, 55 years) were undergoing CAPD treatment and 12 RFPs (two women and ten men; mean age, 62 years) were undergoing HD treatment. Muscle biopsies from gastrocnemius muscles were found not to differ ( P >0.05) in fibre type distribution, MyHC (myosin heavy chain) expression or fibre CSA (cross-sectional area) between the two groups. There were, however, significant differences ( P <0.05) in CC/F (capillary contact/fibre), C/F (capillary to fibre ratio) and cytochrome c oxidase activity. The HD group had 33% more CC/F, with a 19% higher C/F and 33% greater cytochrome c activity in glycolytic fibres (II) than the CAPD group. There were no apparent differences in age, gender, co-morbidity, self-reported physical activity or physical functioning between the two groups, which could account for the difference in muscle capillarity between the groups. The HD patients were, however, administered heparin as a routine part of the dialysis therapy. The possibility is discussed that heparin in combination with mild anaemia and acidosis may have augmented angiogenesis in the HD patients.

Two studies were performed to assess the entero-insular axis in simple obesity and the possible effect of variations in the level of circulating non-esterified fatty acids (NEFA) on one of the components of the entero-insular axis, glucagon-like peptide-1 [(7–36) amide]. In the first study, we compared the entero-pancreatic hormone response to oral carbohydrate in obese and lean women. Obese subjects demonstrated hyperinsulinaemia and impaired glucose tolerance but this was not associated with an increased secretion of either glucose-dependent insulinotropic polypeptide or glucagon-like peptide-1 (GLP-1). These findings therefore provide no support for the hypothesis that overactivity of the entero-insular axis contributes to the hyperinsulinaemia seen in obesity. Indeed, the plasma GLP-1 response to carbohydrate was markedly attenuated in obese subjects, confirming previous observations. In the second study, in which carbohydrate-stimulated GLP-1 responses were again evaluated in obese and lean women, circulating NEFA levels were modulated using either heparin (to increase serum NEFA) or acipimox (to reduce serum NEFA). Treatment with acipimox resulted in complete suppression of NEFA levels and in a markedly higher GLP-1 response than the response to carbohydrate alone or to carbohydrate plus heparin. We suggest that higher fasting and postprandial NEFA levels in obesity may tonically inhibit nutrient-mediated GLP-1 secretion, and that this results in attenuation of the GLP-1 response to carbohydrate. However, although serum NEFA levels post-acipimox were similarly suppressed in both lean and obese subjects, the GLP-1 response was again significantly lower in obese subjects, suggesting the possibility of an intrinsic defect of GLP-1 secretion in obesity. The reduction of GLP-1 levels in obesity may be important both in relation to its insulinotropic effect and to its postulated role as a satiety factor.

1. Hypotension and vascular hyporesponsiveness to vasoconstrictors are observed during endotoxic shock, and are associated with increased production of nitric oxide in the vascular wall. Disseminated intravascular coagulation is another feature of septicaemia. We hypothesized that thrombin generated during disseminated intravascular coagulation might modulate the changes in vascular tone induced by endotoxin. 2. Incubation of rat aortic rings for 4 h with α-thrombin (0.003–3.0 NIH units/ml) did not change their reactivity to noradrenaline. Incubation for 4 h with lipopolysaccharide increased the EC 50 for noradrenaline, whereas co-incubation of thrombin (0.5 NIH units/ml) with lipopolysaccharide did not alter this hyporeactivity to noradrenaline. 3. In vivo in rats, lipopolysaccharide caused early (1 h) and late (4–6 h) hyporeactivity to noradrenaline. In rats infused with lipopolysaccharide and heparin (1 U min −1 kg −1 , 0.4 ml/h) or hirudin (2.2 mg ml −1 kg −1 , 0.8 ml/h), vasopressor responses to noradrenaline were not different from those after infusion of lipopolysaccharide alone. Aortic rings taken from rats receiving both anticoagulant treatment and lipopolysaccharide had the same sensitivity to noradrenaline as those obtained from rats receiving lipopolysaccharide alone. 4. Our results suggest that, in vivo , disseminated intravascular coagulation does not modify the early and late effects of lipopolysaccharide on arterial pressure and that, in vitro , thrombin neither induces hyporeactivity to noradrenaline nor modifies lipopolysaccharide-induced hyporeactivity. We propose that thrombin generated during disseminated intravascular coagulation in rats does not play a major role in the alterations of vascular tone observed during endotoxic shock.

1. The effects of spermine in the concentration range 0–10 mmol/l on (a) the fluid absorption, (b) the polyethylene glycol permeability, (c) the release of collagenase activity activity into the lumen and (d) the histological appearance of rat descending colon were examined. 2. Spermine (5 mmol/l) decreased fluid absorption from 48.83 ± 2.98 ( n = 7) to 23.98 ± 2.32 ( n = 6) μl h −1 cm −2 ( P <0.01); polyethylene glycol 4000 permeability was increased from 0.030 ± 0.001 ( n = 7) to 0.047 ± 0.003 ( n = 6) cm/h ( P <0.01) and luminal collagenase activity increased from a negligible control value to 250 ± 39 ( n = 6) units/ml ( P <0.001). Spermine also caused oedema formation within the mucosal interstitial fluid, without inducing an overt breakdown of the mucosa at the luminal surface. 3. Polyamine-free dialysed seminal plasma had no effect on polyethylene glycol 4000 permeability, although it still caused a significant decrease in colonic fluid absorption from 48.83 ± 2.98 ( n = 7) (control) to 31.41 ± 2.08 (n = 5) μl h −1 cm −2 ( P <0.01). 4. Low-molecular-mass heparin (600 units/ml) prevented the spermine (5 mmol/l)- and whole-semen-induced increase in colonic polyethylene glycol 4000 permeability and reduced the effect of semen on fluid absorption by 63% ( P <0.001) and that of spermine by 56% ( P <0.01). 5. The Zn 2+ chelator and collagenase inhibitor o -phenanthroline reduced the effect of spermine on fluid absorption and polyethylene glycol 4000 permeability by 100% ( P <0.001) and on interstitial oedema formation. o -Phenanthroline also reduced the effects of whole semen on fluid absorption (by 70%, P <0.01) and on polyethylene glycol 4000 permeability by 95%, P <0.01). 6. A synthetic peptide inhibitor of mammalian collagenase activity with high affinity reduced the effects of whole semen on polyethylene glycol 4000 permeability ( P <0.01) and on fluid absorption ( P <0.01) in a dose-dependent manner. The inhibitor (2 mmol/l) also reduced the effects of spermine (5 mmol/l) on fluid absorption and polyethylene glycol 4000 permeability. 7. These results indicate that polyamines that are present within semen in the concentration range 5–15 mmol/l act co-operatively with seminal collagenases to disrupt the colonic barrier. Cationic polyamines may activate collagenases by binding to and neutralizing the anionic charge of heparins within the interstitial matrix.

1. Heparin and heparan sulphate strongly inhibited human leucocyte elastase activity in an automated assay using the soluble substrate, n -succinyl-( l -alanine) 3 - p -nitroanilide (50% inhibition of 250 μl of 10 μg of human leucocyte elastase/ml was obtained with 80 μl of 2.8 μg of heparin/ml and 8 μg of heparan sulphate/ml). Less significant inhibition at the same concentrations was seen with the other glycosaminoglycans tested: hyaluronic acid and chondroitin sulphates A–C. 2. Heparin and heparan sulphate also strongly inhibited human leucocyte elastase activity towards insoluble human lung elastin, as determined by an e.l.i.s.a. for soluble elastin-derived peptides released by elastolytic activity on the elastin. This inhibition was shown not to be due to a direct interference of the glycosaminoglycans in the e.l.i.s.a. nor to the inhibition causing a change in the size of the elastin-derived peptides. However, unlike the chromogenic assay with n -succinyl-( l -alanine) 3 - p -nitroanilide as substrate, where heparin was the more effective inhibitor, in this assay system heparan sulphate was the more effective inhibitor (50% inhibition of 100 μl of 50 ng of human leucocyte elastase/ml was obtained with 100 μl of 4.5 μg of heparin/ml and 0.8 μg of heparan sulphate/ml). These results suggest that heparin and heparan sulphate, as components of cellular and basement membranes, are likely to have a role in protecting structural proteins, such as elastin, from the proteolytic activity of human leucocyte elastase. 3. The degree of inhibition by heparin was independent of pH within the range of pH studied (pH 6–9) and was almost immediate in the automated chromogenic assay system where a 10 s preincubation step was used. The inhibitory effect of heparin could be prevented by the addition of protamine sulphate or by the removal of heparin by an ion-exchange resin. 4. Low M r preparations of heparin were also found to inhibit human leucocyte elastase, although preparations with M r of 2000 or less did not inhibit the enzyme to the same extent as commercial preparations. 5. Heparin at the same concentrations did not inhibit other leucocyte enzymes, such as cathepsin G and myeloperoxidase, nor the pancreatic enzymes, pancreatic elastase, trypsin and chymotrypsin.

1. Commercial heparin and acid glycosaminoglycans (AGAG) prepared from normal female human urine were tritiated catalytically in aqueous solution. Nasal septal chondroitin sulphate was tritiated by NaB 3 H 4 reduction of the aldehydes produced by very limited periodate oxidation. The refined products were characterized by electrophoresis and biochemical analysis. 2. The tritiated products were infused into Munich-Wistar rats, and their kidney clearances were measured and compared with that of inulin. 3. The passage of heparin and chondroitin sulphate at the glomerulus was restricted, as shown by the ratios of their concentrations in Bowman's space fluid and plasma. Comparison with whole kidney urine/plasma ratios indicated that some tubular reabsorption also occurred. The low whole kidney clearance of AGAG from normal female human urine probably also resulted from restricted glomerular passage and tubular reabsorption. 4. The low whole kidney clearances, primarily caused by restricted transglomerular movement, are discussed on the bases of (a) the molecular sizes and shapes of the AGAG, (b) an electrostatic barrier at the basement membrane and (c) binding of AGAG to plasma colloids, thus reducing plasma levels of free AGAG. 5. The implications of these findings in (a) heparin therapy and (b) urinalysis of disorders of connective tissue metabolism are discussed.

1. Bone loss was assessed by measurement of cortical thickness of metacarpal bone by X-ray and of trabecular bone area in serial bone biopsies in 49 patients with chronic renal failure, six before and 45 during maintenance haemodialysis treatment. 2. Metacarpal cortical measurements (MCM) were very reproducible (coefficient of variation 1·95%), whereas bone area measurements by histology showed great variability. There was no correlation between rates of change of MCM and bone area over the same period, although both tended to fall with time. 3. The mean annual rate of bone loss measured by MCM for patients on dialysis was 2·08 ± 0·32 mm/year (mean ±1 sem) and this rate was not significantly different from the mean rate of loss of 2·49 ± 0·78 mm/year for the six patients who were not on maintenance haemodialysis. 61% of all patients showed a significant decrease during the period of study (1–6 years), but none had symptoms attributable to bone loss. 4. The loss tended to be greatest in women over the age of 40 years. The initial amount of bone and the rate of loss measured by MCM or bone histology were not influenced significantly by the presence or absence of histological or radiological evidence of parathyroid overactivity or of osteomalacia, nor by differences in the causes of renal disease. 5. Loss of metacarpal cortical bone correlated with heparin consumption during haemodialysis in men but not in women. The amount of bone and its rate of loss was not influenced by the presence of an arteriovenous shunt in one arm compared with the other. In neither sex did bone loss correlate with physical activity. 6. A relative deficiency of calcium due to a low dietary calcium intake and intestinal malabsorption of calcium, together with a dialysate calcium of only 1·5 mmol/l, may be more important causes of bone loss in patients in this study.

1. Heparin has been shown to increase platelet aggregation by ADP and adrenaline and to enhance the platelet release reaction when tested in citrated platelet-rich plasma (P.R.P.). This activity is present when heparin is added to P.R.P. or when P.R.P. is prepared after intravenous injection of heparin, and when heparin is added to non-anticoagulated native P.R.P. 2. Retention of platelets by cellophane membranes within a specially designed test-cell was significantly increased when heparin was added to citrated whole blood. 3. Though aspirin blocks the release reaction with and without heparin, it does not prevent the potentiation of initial ADP or first wave adrenaline aggregation caused by heparin.