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Biomedical subjects

C R Prentice

Publications and source records attributed to C R Prentice.

At least 145 records · Page 8Linked to original sources
PubMed1977

Poisoning by bites of the saw-scaled or carpet viper (Echis carinatus) in Nigeria.

The Saw-scaled or Carpet Viper (Echis carinatus) whose range extends from Senegal to Bengal probably bites and kills more people than any other species of snake. One hundred and fifteen patients with poisoning caused by its bite were studied in the savanna region of Nigeria, where victims of this snake may occupy 10 per cent of hospital beds. Patients showing no signs of envenoming were excluded. All patients had local swelling at the site of the bite. Other features included local blistering (13 per cent), local necrosis (11 per cent), incoagulable blood (93 per cent), and spontaneous systemic bleeding (57 per cent). There was evidence of disseminated intravascular coagulation in all cases; fibrinogen was severely depleted, fibrin degradation products were increased (mean 1711 +/- 904 micron per ml), but significant thrombocytopenia (less than 103 000 per mm3) was seen in only ten severe cases. Clotting factors V, VIII, II and XIII were depleted, while X and VII were usually normal. Fibrinolytic activity was rarely increased, so it seems likely that a procoagulant action (direct activation of prothrombin) is principal effect of E. carinatus venom on blood coagulation in man. Development of the haemostatic defect was observed as early as 75 minutes and as late as 27 hours after the bite. Spontaneous haemorrhage is clinically the most important effect of E. carinatus venom, causing the five deaths in this series. The relative importance of procoagulant and haemorrhagic components of the venom in causing haemorrhage is discussed. Complement activation via the classical and alternative pathways may have contributed to vascular damage. Mortality was reduced from the untreated level of between 10 and 20 per cent to 2.8 per cent in a group of 107 patients treated with 10 to 110 ml of specific antivenom. The dose was controlled using a simple clotting test. Blood coagulability was restored in two to 39 (mean 12) hours after the first dose of antivenom. Immediate-type serum reactions were observed in 21 per cent of cases. Additional treatment included blood transfusion for patients in haemorrhagic shock and ealry surgical débridement of necrotic tissue at the site of the bite.

Adolescent↗
PubMed1976

The incidence of deep vein thrombosis in prostatectomised patients following the administration of the fibrinolytic inhibitor, aminocaproic acid (EACA).

Forty patients undergoing prostatectomy for benign prostatic hypertrophy were included in a double blind trial of epsilon aminocaproic acid, and the incidence of postoperative deep vein thrombosis determined, using 125I-fibrinogen technique. There was no significant difference between the groups, the overall incidence of abnormal scans being 50 per cent, but of the patients undergoing enucleative prostatectomy 68 per cent developed significant scan findings compared with 33 per cent following transurethral surgery.

Aged↗
PubMed1976

Cost of management of patients with haemophilia.

The cost of managing 114 adult haemophiliacs in the west of Scotland was assessed for the period 1 March 1971 to 28 February 1974. Altogether 23 of them (20%) accounted for 80% of the resources used. The cost of hospital treatment of these patients during the period was compared with the predicted cost of home treatment, given the availability of freeze-dried factor VIII concentrate in sufficient amounts. We calculate that adequate on-demand home treatment would cost only 16% more than the present treatment, which is substantially less efficient.

Adult↗
PubMed1976

Use of coagulation tests to predict the clinical progress of pre-eclampsia.

The clinical manifestations of severe pre-eclampsia are normally separated from those of mild pre-eclampsia and normal pregnancy on arbitrary grounds. A clinical index, based on the increase in diastolic blood-pressure and the presence of proteinuria, was developed to reflect the spectrum of disease from mild to severe pre-eclampsia. This was related to a coagulation index based on the platelet-count, plasma-factor-VIII, and serum-fibrinolytic-degradation-products. The two indices were shown to be strongly correlated. All cases of perinatal death associated with pre-eclampsia had coagulation indices in the most severely abnormal range. These results suggest that intravascular coagulation is a highly characteristic feature of pre-eclampsia and that the coagulation index may be of value in monitoring the progress of the disease.

Blood Cell Count↗
PubMed1976

Effects of chlorprothixene isomers on platelet 5-hydroxytryptamine receptors: evidence for different 5-hydroxytryptamine conformations at uptake and stimulatory sites.

The thioxanthene neuroleptic, cis-chlorprothixene, was approximately 200 times more potent than its transisomer as an inhibitor of the aggregation of human blood platelets induced by 5-hydroxytryptamine (5HT). Against the active uptake of 5HT by these cells, however, trans-chlorprothixene was twice as inhibitory as its cisisomer, and this inhibition was found to be competitive. It is suggested that 5HT adopts different conformations for binding to its two platelet receptors.

Binding Sites↗
PubMed1976

Disseminated intravascular coagulation caused by the carpet viper (Echis carinatus): trial of heparin.

Heparin has been advocated for the treatment of poisoning by Echis carinatus, a snake whose venom causes disseminated intravascular coagulation. Fourteen patients with proven E. carinatus bite who had incoagulable blood were treated with specific Echis antivenom. Seven of them were also given low-dose heparin, initially 50 units/kg body weight by i.v. injection, followed by 10 units/kg/h by i.v. infusion for 22 h. Response to treatment was assessed clinically and by repeated tests of blood coagulation. All patients showed a rapid return to normal blood coagulability after treatment and the heparinized group were not significantly different in any respect from the group given antivenom alone. Heparin did not reduce the local effects of envenoming. There appears to be no place for heparin in the treatment of E. carinatus poisoning provided that potent antivenom is available. The in vivo results were supported by in vitro studies in which it was found that Echis-induced thrombin was less sensitive to the inhibitory effect of heparin than physiological thrombin.

Antivenins↗
PubMed1976

Treatment of thrombosis by sequential therapy with ancrod followed by streptokinase. Clinical pharmacology and rheology.

The effects of sequential therapy with ancrod followed by streptokinase are reported in a series of patients with thrombotic disease. Measurements have been made in blood coagulation, fibrinolysis and whole blood and plasma viscosity. Intravenous infusion of ancrod resulted in a significant reduction in plasma fibrinogen which was associated with highly significant reduction in both plasma and whole blood viscosity. Sequential therapy with streptokinase resulted in a gradual rise in fibrinogen and a slight but significant rise in whole blood and plasma viscosity. All patients showed clinical improvement and no haemorrhagic complications resulted.

Ancrod↗
PubMed1976

Necrosis, haemorrhage and complement depletion following bites by the spitting cobra (Naja nigricollis).

The Spitting Cobra, Naja nigricollis, is widely and densely distributed in Africa. Fourteen patients with proven N. nigricollis bites, who were seen in the savanna region of Nigeria, did not exhibit the neurological signs, such as cranial nerve lesions and respiratory paralysis, expected following Elapid poisoning. All had local swelling, in eight cases involving the entire limb, and ten developed local tissue necrosis. Spontaneous haemorrhage was detected in three cases and was the probable cause of death in one of them; the other death in this series was unexplained. Haematological abnormalities included prolonged clot lysis anf failure of clot retraction due to a platelet defect. There was no specific deficit in clotting factors and a delayed rise in fibrin degradation products was attributed to extensive tissue damage at the site of the bit. Most patients showed depletion of complement component C3 and glycine-rich beta-glycoprotein (GBG), suggesting activation of the alternative pathway of complement fixation. There was evidence of hepatocellular damage in two out of six patients investigated. There was no evidence that specific polyvalent antivenoms, used in doses of up to 80 ml, prevented any of the effects of N. nigricollis venom. Clinical laboratory diagnosis is discussed. In the past many bites were wrongly classified as viper bites on the basis of clinical findings. Immunodiagnosis is a promising method for assessing the true importance of N. nigricollis bite in West Africa.

Adolescent↗
PubMed1975

Calculation of predictive odds for possible carriers of heamophilia.

Betting odds for possible carriers of haemophilia have been calculated using data derived from normal and known carrier populations. For each possible carrier the concentration of factor VIII-related antigen and factor VIII biological activity was measured and used to determine the probability of the individual being a carrier. The calculations indicated that, of the 32 possible carriers, 11 were likely to be normal (odds of more than 5:1) while 11 were likely to be haemophilia carriers (again odds of more than 5:1).

Antigens↗