A prospective observational phase IV study on effectiveness of animal derived polyclonal antibody antivenoms against West African carpet viper (Echis romani) induced coagulopathy and mortality.

Conventional polyclonal antibody antivenoms are the mainstay of snakebite therapy. They have not been proven to be efficacious in randomized placebo controlled clinical trials among severely envenomed patients. There is also paucity of evidence on effectiveness especially in routine use. The current study evaluated their effectiveness in post marketing use among those managed with and without antivenom as regards to reversal of venom induced coagulopathy defined using the 20 min Whole Blood Clotting Test [20WBCT] and in averting death. The effectiveness of antivenom was evaluated among 5467 patients predominantly envenomed by the West African carpet viper (Echis romani) at 3 hospitals in Nigeria from 2021 to 2022. Two antivenoms Echitab G (EG) and Echitab ICP Plus (EP) were able to restore normal clotting within 6 h of administration in 58.0% [95% Confidence Interval (95%CI)] (51.2-64.5%) and 91.7% (90.4-93.0%) of patients respectively. They were able to restore normal clotting within 24 h of administration in 96.9% (94.0-98.7%) and 99.0% (98.4-99.4%) of patients respectively. The Odds Ratio [OR (95%CI)] of dying among patients with positive 20WBCT who were treated with ≥1 vial of either EG or EP compared to those not treated was 0.06 (0.02-0.23) and 0.07 (0.03-0.15) respectively. This equated to antivenom protection against in-hospital mortality of 93-94% among patients with confirmed coagulopathy though the benefit appeared abrogated among those without coagulopathy. The untreated natural mortality was 15.94% (95%CI:8.24-26.74%) without antivenom therapy while the overall mortality was 84/5105 (1.65%; 95%CI:1.32-2.03%. The Number Needed to Treat (NNT) to avert a death was 7 patients among those with coagulopathy. Antivenoms were safe with mild early adverse reactions observed among 2.6% (95%CI:2.13-3.08%) of antivenom recipients. Polyclonal antibody antivenoms are effective and safe for treating coagulopathic envenomed patients in Nigeria.

Comparison of snakebite in children and adults in Nigeria.

Snakebite envenoming is a major global public health problem and disproportionately affects children. To study the differences in clinical presentation and outcomes between children and adults, 2922 snakebite patients of whom 30.3% were children were analysed. Most bites (>75%) were in the lower. Features of local envenoming were commoner among children compared to adults (p < 0.05), while systemic envenoming features, mortality and complications were similar, p = 0.356, p = 0.12, and p = 0.16 respectively.

Performance of the 20 minutes Whole Blood Clotting Test in detection, monitoring and antivenom therapy of West African Carpet viper (Echis romani) envenoming in resource constrained settings in Nigeria.

The 20 minutes Whole Blood Clotting Test (20WBCT) was evaluated in 1541 snakebite patients at 3 hospitals in Nigeria. It was useful in detection, monitoring, guiding antivenom therapy and prognostication of coagulopathy, with initial sensitivity of 84.7% (95%CI:82.7-86.5%) and specificity of 64.3% (95%CI:50.4-76.7%) compared to clinical envenoming. It led to correct decisions regarding administration or withholding antivenom in 97.93% of patients. The proportion of carpet viper (Echis romani) envenomed patients who restored clotting rose steadily following effective antivenom therapy. Patients with positive 20WBCT had severer envenoming, required more blood transfusion, had longer hospital stay and derived higher antivenom protection against death from carpet viper. However, there was no association between positive 20WBCT and fatality or complications.

Moving beyond the concept of "primary forest" as a metric of forest environment quality.

The United Nations Food and Agriculture Organization (FAO) has been reporting country-level area in primary forests in its Global Forest Resource Assessment since 2005. The FAO definition of a primary forest (naturally regenerated forest of native species where there are no clearly visible indications of human activities and the ecological processes are not significantly disturbed) is generally accepted as authoritative and is being used in policy making. However, problems with this definition undermine our capacity to obtain globally coherent estimates. In addition, the current reporting on primary forests fails to consider the complementarily of non-primary forests toward the maintenance of ecosystem services. These issues undermine the appropriate tracking of changes in primary and non-primary forests, and the assessment of impacts of such changes on ecosystem services. We present the case for an operational reconsideration of the primary forest concept and discuss how alternatives or supplements might be developed.

The EF-hand Ca(2+)-binding protein p22 associates with microtubules in an N-myristoylation-dependent manner.

Proteins containing the EF-hand Ca(2+)-binding motif, such as calmodulin and calcineurin B, function as regulators of various cellular processes. Here we focus on p22, an N-myristoylated, widely expressed EF-hand Ca(2+)-binding protein conserved throughout evolution, which was shown previously to be required for membrane traffic. Immunofluorescence studies show that p22 distributes along microtubules during interphase and mitosis in various cell lines. Moreover, we report that p22 associates with the microtubule cytoskeleton indirectly via a cytosolic microtubule-binding factor. Gel filtration studies indicate that the p22-microtubule-binding activity behaves as a 70- to 30-kDa globular protein. Our results indicate that p22 associates with microtubules via a novel N-myristoylation-dependent mechanism that does not involve classic microtubule-associated proteins and motor proteins. The association of p22 with microtubules requires the N-myristoylation of p22 but does not involve p22's Ca(2+)-binding activity, suggesting that the p22-microtubule association and the role of p22 in membrane traffic are functionally related, because N-myristoylation is required for both events. Therefore, p22 is an excellent candidate for a protein that can mediate interactions between the microtubule cytoskeleton and membrane traffic.

Efegatran sulfate as an adjunct to streptokinase versus heparin as an adjunct to tissue plasminogen activator in patients with acute myocardial infarction. ESCALAT Investigators.

BACKGROUND: Previous clinical studies have shown that direct antithrombins can accelerate clot lysis after treatment with streptokinase in acute myocardial infarction (MI). Efegatran is a new direct antithrombin, which in experimental animals has been shown to enhance thrombolysis, reduce rate of reocclusion, and limit infarct size. This study was designed to compare the efficacy of efegatran plus streptokinase versus heparin plus accelerated tissue plasminogen activator (TPA) in coronary reperfusion in acute MI. METHODS AND RESULTS: In this randomized, dose-finding study (n = 245), we initially explored 4 doses of efegatran sulfate in combination with streptokinase (1.5 million U) given intravenously within 12 hours of symptom onset. The optimal dosage group of 0.5 mg/kg per hour was expanded and compared with heparin plus accelerated TPA. The primary end point was complete patency (Thrombolysis In Myocardial Infarction [TIMI] grade 3) at 90 minutes after thrombolytic therapy, assessed in a core angiographic laboratory. Infarct-related vessel patency (TIMI grade 2 or 3) and complete patency (TIMI grade 3) were 73% and 40% in the efegatran/streptokinase group versus 79% and 53% in the heparin/TPA group (P = not significant). In-hospital mortality rate was 5% for the efegatran/streptokinase group versus 0% for the heparin/TPA group (P = not significant). Major bleeding occurred in 23% of patients in the efegatran/streptokinase group versus 11% in the heparin/TPA group (P = not significant). No intracranial hemorrhage occurred. CONCLUSIONS: The combination of efegatran plus streptokinase is not superior to the current therapy of heparin and accelerated TPA in achieving early patency. In addition, there is no indication that this experimental treatment can achieve better clinical outcome.

Percutaneous rotational thrombectomy reduces acute reocclusion in an animal model of acute coronary thrombosis.

This study was designed to compare acute reocclusion rates after treatment of acute coronary thrombosis with a percutaneous thrombectomy device or standard balloon angioplasty. Our group has previously reported on the rationale and development of a mechanical device for the treatment of intra-arterial thrombosis. This device removes fibrin from thrombus, allowing for dissolution of the cellular elements of the thrombus. Theoretically, thrombus removal (as opposed to displacement) might result in a lower rate of acute rethrombosis. The present study utilizes the device percutaneously in the coronary arteries of closed chest swine and compares recanalization and reocclusion rates with standard balloon angioplasty. Twenty-six animals with total thrombotic coronary occlusions were treated; 13 with each device. Reocclusion rates with the thrombectomy device were significantly reduced at 60 min and 120 min after recanalization (p < 0.02), and the mean time to reocclusion was prolonged by 45 min (p = 0.07). Technical problems included poor handling characteristics in early prototypes and stress fractures secondary to improper use. Changes in catheter design and operator protocols have largely eliminated these problems. We conclude that this study demonstrates the feasibility of percutaneous mechanical thrombectomy in the coronary arteries and that reocclusion rates after recanalization of thrombotic occlusions compare favorably to standard angioplasty.

Asymptomatic myocardial ischemia during percutaneous transluminal coronary angioplasty and importance of prior Q-wave infarction and diabetes mellitus.

Eighty-eight patients undergoing percutaneous transluminal coronary angioplasty (PTCA) of 100 stenoses were studied for the presence of factors deemed significant in the etiology of silent myocardial ischemia. Thirty-two patients were asymptomatic during balloon dilations of 36 arteries, and 56 patients had angina during PTCA of 64 arteries. There were no differences in age, sex, prior anginal history, antianginal regimen, extent of coronary artery disease and number or duration of inflations between the 2 study groups. Previous infarction (33 vs 12%, p less than 0.02), Q waves in the target area (31 vs 7%, p less than 0.005) and diabetes mellitus (36 vs 17%, p less than 0.05) were present more often in the asymptomatic group. Sixty-four% of all asymptomatic patients had either diabetes or previous infarction in the target territory. Collateral circulation was more frequent in asymptomatic patients, probably reflecting the ability of collateral arteries to ameliorate ischemia. During 2-vessel PTCA, patients without angina during dilation of only 1 of the 2 treated arteries (discordant responders) had previous infarction in that artery's territory (5 of 5, 100%), whereas patients without previous infarction were either symptomatic or asymptomatic (concordant responders) during PTCA of both arteries. This study shows that asymptomatic ischemia occurs frequently during PTCA in patients with symptomatic coronary disease. Prior Q-wave infarction and diabetes mellitus are important, independent factors associated with painless ischemia. It is suggested that infarction produces a localized dysfunction of afferent cardiac pain fibers, whereas diabetes can cause a global cardiac sensory neuropathy.

Distal embolization during mechanical thrombolysis: rotational thrombectomy vs. balloon angioplasty.

To determine the incidence and extent of distal embolization during percutaneous transluminal balloon angioplasty (PTA) and rotational thrombectomy (PRT), we collected, filtered, and weighed the distal effluent of acute thrombotically occluded canine arteries following mechanical thrombolysis. PRT (n = 11) and PTA (n = 10) were equally effective in recanalizing occluded vessels (91% vs. 90%) and reduced percent diameter stenosis to a similar degree (97 +/- 6% to 8 +/- 11% and 100 +/- 0% to 17 +/- 23%, respectively). Distal embolization following mechanical intervention was observed in 10 of 10 and 8 of 9 arteries recanalized with PRT and PTA, respectively. The mean weights of collected emboli were similar between the two groups (18 +/- 24 mg vs. 37 +/- 79 mg, PRT vs. PTA, P = NS), although the range of size and weight of thromboemboli was larger in the PTA group (0-206 mg vs. 2-51 mg, PRT). Angiographically defined residual thrombus was significantly less frequent in arteries recanalized with PRT as compared with PTA (10% vs. 55%, P = 0.03). In summary, PRT and PTA are equally effective in recanalizing acutely occluded canine arteries and result in similar reductions in percent diameter stenosis. Each intervention results in distal embolization of thrombi. PRT is associated with a reduced incidence of angiographically evident residual thrombus at the site of arterial injury and may avoid embolization of large fragments occasionally produced by PTA. Thus PRT may serve as a useful alternative to coronary angioplasty during acute myocardial infarction.

Inhibition of prostaglandin biosynthesis by eicosapentaenoic acid.

Eicosapentaenoic acid [20 : 5 (n-3)] is not oxidized by the purified cyclooxygenase from sheep vesicular glands in the conditions of low peroxide tone in which arachidonate [20 : 4 (n-6)] is rapidly oxygenated. When the level of peroxide in incubation mixtures is allowed to rise, there is a dramatic change in reactivity of the cyclooxygenase to react with 20 : 5 (n-3) at one-halt the rate and one-third the extent observed with 20 : 4 (n-6). Overall, the low peroxide levels expected in vivo would most probably cause the (n-3) type of fatty acid to be a general inhibitor of prostaglandin formation, through both reversible and irreversible actions at the enzyme site.

Determination of binding affinities of retinoids to retinoic acid-binding protein and serum albumin.

Binding affinities of retinoic acid and its synthetic analogues to intracellular retinoic acid-binding protein, which is a possible candidate for mediating their biological function, and to serum albumin, the plasma transport protein, were evaluated. A quantitative method involving elimination of interfering serum albumin by immunoprecipitation was developed to measure the binding efficiency of these retinoids, some of which are active in modifying epithelial differentiation and preventing tumorigenesis. Two cyclopentenyl analogues of retinoic acid and 13-cis-retinoic acid showed, like retinoic acid, a binding efficiency of 100% for the cellular binding protein. With the phenyl, dichlorophenyl and trimethylmethoxyphenyl analogues of retinoic acid, the binding efficiency increased as the substituents on the aromatic ring increased; thus the trimethylmethoxyphenyl analogue binds almost as efficiently as retinoic acid itself. However, the trimethylmethoxyphenyl analogue with a sulphur atom on the side chain has a much decreased binding affinity. The correlation noticed between the binding efficiency of these retinoids and their biological activity in differentiation and/or in the control of tumorigenesis particularly enhances the confidence in the present method of determining the relative binding efficiencies. None of the vitamins, hormones and cofactors tested, showed appreciable affinity for the retinoic acid-binding site. Studies on binding of retinoic acid and its analogues to serum albumin indicate that no correlation exists between binding affinity for albumin and their biological potency.

Retinoic acid-binding protein in experimental tumors and in tissues with metastatic tumor foci.

Screening for retinoic acid-binding protein (RABP) in experimental tumors revealed the presence of this protein in three mammary tumors, two metastatic colon tumors, B16 melanoma. Lewis lung carcinoma, Ridgway osteogenic sarcoma, and keratoacanthoma. RABP was below the limits of detection in two weakly metastatic colon tumors and in Sarcoma 180. After s.c. implantation of RABP-containing tumors into mice, this protein could be traced in the lungs due to pulmonary metastasis. Following implantation of Lewis lung tumors, RABP was detected in the lung on the 6th day. On the 15th day after implantation, RABP was present in lung and brain, but not in other tissues where this protein was normally lacking. In primary cultures of Lewis lung carcinoma, the lower limit for detection of RABP by sucrose gradient sedimentation technique corresponded to 0.12 mg protein that was extractable from 3 X 10(5) cells. Both chick embryo skin and rabbit ear skin extracts contained RABP; the level of cellular retinol-binding protein was high in chick embryo skin but only marginal in rabbit ear. The amounts of these proteins on chick embryo skin and rabbit ear skin correlate with the biological potency of retinol and retinoic acid, as observed by others.