Evaluation of the anticonvulsant and muscle relaxant effects of the methanol root bark extracts of Annona senegalensis

ObjectiveTo investigate the potentials of the root bark of Annona (A.) senegalensis in the control of seizure and related hypnotic and motor incoordination effects in mice using experimental models.MethodsThe methanol extract (ME) of the root bark of A. senegalensis was studied in mice using pentylenetetrazole (PTZ) induced convulsions, phenobarbitone induced sleeping time and motor coordination test on rota-rod performance. Acute toxicity and lethality (LD₅₀) test as well as phytochemical analysis were also carried out.ResultsThe extract (200, 400, 800 mg/kg) exhibited a non-dose dependent significant (P <0.05) delay in the onset of both tonic and clonic phases of seizure induced by PTZ (60 mg/kg, s.c.) as well as offered a 100% protection (200 mg/kg) in mice from PTZ induced seizures. The extract significantly (P <0.05) decreased the latency and increased the duration of phenobarbitone induced sleeping time. At 200 mg/kg, the extract exhibited a significant (P <0.05) motor incoordination. The acute toxicity test revealed an oral LD₅₀ of 1 296 mg/kg, while the phytochemical studies showed the presence of alkaloids, resins, glycosides, carbohydrate, reducing sugar, flavonoids, terpenoids, saponins and tannins.ConclusionThe extract of A. senegalensis possessed anticonvulsant activity with pronounced hypnotic and muscle relaxant effects.     

Novel cardioprotective effects of tetrahydrobiopterin after anoxia and reoxygenation: Identifying cellular targets for pharmacologic manipulation

OBJECTIVES: Contemporary cardioprotective strategies to prevent perioperative ischemia-reperfusion injury have focused on the l-arginine nitric oxide pathway. Tetrahydrobiopterin is an absolute cofactor required for the enzyme nitric oxide synthase and is thus a critical determinant of nitric oxide production. We hypothesized that ischemia-reperfusion results in diminished levels of tetrahydrobiopterin, which might represent a key cellular defect underlying endothelial and myocyte dysfunction after ischemia-reperfusion. To this aim, we examined the effects of tetrahydrobiopterin supplementation in (1) an in vivo experimental model of global ischemia-reperfusion and (2) an in vitro human ventricular heart cell model of simulated ischemia-reperfusion. Measures of endothelial function, oxidant production, cell survival, and cardiac function were used to assess outcome. METHODS: In study 1 Wistar rats were divided into one of 2 groups (n = 10 per group). One group received tetrahydrobiopterin (25 mg x kg(-1) x d(-1) for 7 days), and the other group served as the control group. Hearts were subjected to 30 minutes of ischemia followed by 30 minutes of reperfusion, and left ventricular developed pressure, left ventricular systolic pressure, and left ventricular end-diastolic pressure were determined by using the modified Langendorff technique. In study 2 we quantitated myocardial malondialdehyde, a marker of lipid peroxidation, in ventricular tissues from both groups of animals using butanol phase extraction and spectrophotometric analysis. In study 3 coronary vascular responses were determined in vascular segments of the left coronary artery in both groups of animals after ischemia-reperfusion. Endothelium-dependent and endothelium-independent vasodilatation to acetylcholine and sodium nitroprusside, respectively, were compared between groups. In study 4, using a human ventricular heart cell model of simulated ischemia-reperfusion, we studied the effects of tetrahydrobiopterin (20 micromol/L) on cellular injury (as assessed by means of trypan blue uptake). RESULTS: After ischemia-reperfusion, myocardial dysfunction was evidenced by a decrease in left ventricular developed pressure and an increase in left ventricular end-diastolic pressure (P =.01 compared with baseline). Hearts from tetrahydrobiopterin-treated rats exhibited protection against ischemia-reperfusion injury (left ventricular developed pressure: 74 +/- 4 vs control 42 +/- 8 mm Hg, P =.01; left ventricular end-diastolic pressure: 12 +/- 3 vs 34 +/- 7 mm Hg, P =.01). Furthermore, tetrahydrobiopterin treatment attenuated the rise in malondialdehyde levels after ischemia-reperfusion (P =.01). After reperfusion, coronary endothelial function to acetylcholine was attenuated (P =.003 vs sham-treated mice), whereas responses to sodium nitroprusside remained unchanged. Tetrahydrobiopterin-treated rats exhibited an improvement in acetylcholine-mediated vasorelaxation (P =.01 vs ischemia-reperfusion group). Cellular injury, as assessed by means of trypan blue uptake, was higher in human ventricular heart cells subjected to simulated ischemia-reperfusion; this effect was prevented with tetrahydrobiopterin treatment (P =.001). CONCLUSIONS: Supplemental tetrahydrobiopterin provides a novel cardioprotective effect on left ventricular function, endothelial-vascular reactivity, oxidative damage, and cardiomyocyte injury after ischemia-reperfusion injury and might represent an important cellular target for future operative myocardial protection strategies.     

Hyperglycemia exaggerates ischemia-reperfusion-induced cardiomyocyte injury: reversal with endothelin antagonism

OBJECTIVES: We have previously demonstrated an importance of endothelin-1 in diabetic patients undergoing bypass surgery. Recent evidence suggests that cardiomyocytes might also produce endothelin-1, which might directly impair myocyte contractility by increasing intracellular calcium levels. Because hyperglycemia is a potent stimulus of endothelin-1 production, we hypothesized that increased production, action, or both of endothelin-1 might be a mediator of direct cardiomyocyte injury in diabetes. Therefore we studied the effects of endothelin receptor blockers (BQ-123 and bosentan) on hyperglycemia-induced endothelin-1 production and cellular injury after ischemia-reperfusion. METHODS: Using a human ventricular heart cell model of simulated ischemia-reperfusion, we studied the effects of normoglycemia (5 mmol/L, 48 hours) and hyperglycemia (25 mmol/L, 48 hours) on cellular injury and endothelin-1 production. Furthermore, the effects of selective endothelin-A and mixed endothelin-A/B receptor antagonism (with BQ-123 and bosentan, respectively) were evaluated. RESULTS: Cellular injury, as assessed by means of trypan blue uptake, was higher in human ventricular heart cells subjected to hyperglycemia and simulated ischemia-reperfusion injury (P =.01); this effect was prevented with both BQ-123 and bosentan (P =.01). In addition, heart cells from the hyperglycemic group elaborated more endothelin-1 after ischemia-reperfusion (P =.02). CONCLUSIONS: Endothelin-1 production and cellular injury were greater in human ventricular heart cells subjected to hyperglycemic conditions and simulated ischemia-reperfusion. These effects are mediated by endothelin-A receptors because both BQ-123 and bosentan exerted similar degrees of protection. Endothelin receptor blockade is a novel strategy to improve the resistance of the diabetic heart to cardioplegic arrest and reperfusion.     

Improved heart function with myogenesis and angiogenesis after autologous porcine bone marrow stromal cell transplantation

OBJECTIVE: The study evaluated the utility of transplanting bone marrow stromal cells in a porcine myocardial infarction model. METHODS: A myocardial infarction was created by occluding the distal left anterior descending artery in pigs with coils and Gelfoam sponge. Sternal bone marrow was aspirated, and stromal cells were cultured and induced to differentiate to a myogenic phenotype with 5-azacytidine. Four weeks after coronary artery occlusion, sestamibi technetium single-photon emission computed tomographic scans were performed, and then either a graft of 100 x 10(6) bone marrow stromal cells (n = 5, 30% labeled with bromodeoxyuridine) or culture medium (n = 6) was injected into the infarct region. Four weeks later the tomographic scans were repeated and cardiac function was assessed with pressure and volume measurements. Morphologic and histologic characteristics of the heart were also studied. RESULTS: Histologic examination found bromodeoxyuridine-labeled cells within the infarct region in islands that had sarcomeres and Z-bands and stained positively for cardiac specific troponin I. The bone marrow stromal cell transplant sites had a greater (P <.05) capillary density than did the control sites. The tomographic scans showed that the hearts with the cell transplants had increases in stroke volume, regional perfusion, and wall motion (P <.05 for all groups) relative to the control hearts. The pressure-volume analysis showed improvement (P <.05) in end-systolic elastance and preload recruitable stroke work in the transplantation group relative to the control group. The left ventricular chamber size was smaller (P <.05) and the scar thickness was greater (P <.05) in the hearts with transplanted cells than in the control hearts (P =.06). CONCLUSION: 5-Azacytidine-treated bone marrow stromal cells transplanted into the myocardial infarct region formed islands of cardiac-like tissue, induced angiogenesis, prevented thinning and dilatation of the infarct region, and improved regional and global contractile function.     

CYP11β1 (11-beta-hydroxylase) deficiency in congenital adrenal hyperplasia

Objective : To review experience of CYP11β1 deficiency (previously known as 11β-hydroxylase) at the Royal Children's Hospital, Melbourne, Victoria.
Methodology : A retrospective case review was conducted from 1974 to 1995 with five cases identified.
Results : Age of presentation ranged from 1 day to 7 years. Presentation was with ambiguous genitatia at birth (two females), simple virilization (two males) and suspected early puberty in mid childhood (one female). Associated clinical features were hypertension (three cases) and tall stature with markedly advanced bone age (four cases). Biochemical abnormalities consistent with CYP11β1-deficiency were elevated urinary tetrahydro-11-deoxycortisol ( n = 5) and elevated serum 11-deoxycortisol ( n = 3). Additional abnormalities were elevated 17-hydroxyprogesterone ( n = 3), elevated androstenedione ( n = 4) and elevated dehydroepiandrosterone sulphate ( n = 4). The clinical features and investigations suggested CYP11β1-classical deficiency in four patients and CYP11β1-non-classical deficiency in one patient.
Conclusions : The five cases of CYP11β1-deficiency demonstrate a spectrum of clinical abnormalities, with diagnostic difficulties in two cases and delayed presentation in three cases. Prompt diagnosis of CYP11β1-deficiency is facilitated greatly by the availability of a gas chromatography-mass spectrometry instrument and is essential to avoid the long-term effects of hypertension and hyperandrogenism.     

The Angiographic Findings in a Haemophilic Pseudotumour of Bone

The angiographic findings in a patient with haemophilic pseudotumour of the femur are presented. The examination showed the position of the displaced femoro-poplited vessels, enabling these structures to be avoided at operation. Under anti-haemophilic globulin cover no complications occurred. It is suggested that angiography may be safely employed provided the coagulation defect is controlled. The examination may be useful in differentiating other bone lesions and in defining more clearly the extent of a haemophilic pseudotumour.