Role of atrial natriuretic peptide in the dissociation between flow relations with ventricular mass and function in a community with volume-dependent hypertension.

Background: Whether differential effects of volume load on left ventricular mass (LVM) and function occur in sustained volume-dependent primary hypertension, and the impact of atrial natriuretic peptide (ANP) on these effects, is unknown. Methods: From aortic pressure, velocity and diameter measurements and echocardiography, we determined in an African community (n = 772), the impact of systemic flow-induced increases in central pulse pressure (PPc) and circulating ANP (ELISA) on LVM and indexes of function. Results: Stroke volume (SV), but not aortic flow (Q), was associated with LVM and mean wall thickness (MWT) beyond stroke work and confounders (p < 0.0001). Adjustments for SV markedly decreased the relationships between PPc and LVMI or MWT. However, neither SV, nor Q were independently associated with either myocardial s', e', or E/e' (p > 0.14) and adjustments for neither SV nor Q modified relationships between PPc and s', e' or E/e' (p < 0.005 to <0.0001). SV was nevertheless strongly and independently associated with ANP (p < 0.0001) and ANP was similarly strikingly associated with s' (p < 0.0001) and e' (p < 0.0005), but not E/e', independent of confounders and several determinants of afterload. Importantly, ANP concentrations were inversely rather than positively associated with LV diastolic dysfunction (DD) (p < 0.005) and lower rather than higher ANP concentrations contributed markedly to the ability to detect DD in those with, but not without LV hypertrophy. Conclusion: In populations with sustained volume-dependent hypertension, flow (SV)-related increases in PP have a major impact on LV structure, but not on function, an effect attributed to parallel striking beneficial actions of ANP on myocardial function.

Attenuated Relationships Between Indexes of Volume Overload and Atrial Natriuretic Peptide in Uncontrolled, Sustained Volume-Dependent Primary Hypertension.

BACKGROUND: Whether systolic blood pressure (SBP) control in sustained volume-dependent primary hypertension is associated with blunted ANP (atrial natriuretic peptide) relationships with indexes of volume load is unknown. METHODS: Systemic hemodynamics (central pressure, echocardiographic aortic velocity and diameter measurements in the outflow tract), circulating ANP concentrations (ELISA assays) and glomerular and tubular function (24-hour urine collections [n=519]) were determined in a community of African ancestry (n=772). RESULTS: As compared with those with a controlled SBP, those with an uncontrolled SBP (n=198) showed lower ANP concentrations (P<0.005) despite higher stroke volume and cardiac output (P<0.0001) and renal differences consistent with enhanced fluid retention. In those with a controlled SBP, fractional Na+ excretion (FeNa+; P<0.0005) and creatinine clearance (glomerular filtration rate; P<0.005) were inversely associated with ANP concentrations independent of confounders. Moreover, in those with a controlled SBP, stroke volume and cardiac output (P<0.0001) were independently and positively associated with ANP concentrations. In addition, in those with a controlled SBP, ANP concentrations were independently and inversely associated with systemic vascular resistance (SVR; P<0.0001) and aortic characteristic impedance (Zc; P<0.005). By contrast, in those with uncontrolled SBP, no relationships between either stroke volume (P>0.25), cardiac output (P>0.29), FeNa+ (P>0.77), or glomerular filtration rate (P>0.47) and ANP concentrations were noted. Furthermore, in those with an uncontrolled SBP, no relationships between ANP concentrations and SVR or Zc were observed (P>0.34). CONCLUSIONS: In a population where primary hypertension is strongly volume-dependent, those with an uncontrolled SBP have an attenuated relationship between ANP and both renal and hemodynamic indexes of volume overload and the vascular effects of ANP.

Immunoreactivity of acetylcholinesterase and M1 muscarinic receptors in the hippocampus and striatum of rats treated with Rebaudioside A.

Rebaudioside A (RebA) is a steviol glycoside used for production of sweeteners. It was shown that the glycosides affect memory and learning processes. The aim of the study was to investigate neurons immunoreactive for acetylcholinesterase (AChE) and M1 muscarinic receptors (mAChRs-M1) of the hippocampal CA1 and CA3 fields and striatal caudateputamen (CP) and globus pallidus (GP) in rats receiving RebA. RebA was administrated to adult rats for 45 days in dilutions of 1 mg and 2 mg RebA/ml water. Indirect peroxidase-antiperoxidase immunohistochemical reaction was conducted on frontal sections containing the hippocampus and striatum with use of antibodies against AChE and mAChRs-M1. Immunoreactive for the studied proteins neurons were morphologically and morphometrically assessed in hippocampal CA1 and CA3 fields and in CP and GP. Microscopic observations did not reveal significant changes in morphology of immunoreactive neurons, which suggests no neurotoxic effect of the studied glycoside on these cells. Morphometric analyses revealed an increase in the density of AChE and mAChRs-M1 immunoreactive neurons. A decrease in reaction intensity of AChE-positive neurons was also demonstrated in the hippocampal CA1 field and in GP. In contrast, an increase in reaction intensity of mAChRs-M1-positive neurons was found in CA1, CA3 fields and in CP and GP. The results of our preliminary studies indicate that RebA administrated to rats has an impact on cholinergic neurons in the studied area. The results suggest a possible increase in the activity of the cholinergic system, responsible for memory and learning processes, after administration of RebA.

Hemodynamic and Functional Correlates of Concentric vs. Eccentric LVH in a Community-Based Sample With Prevalent Volume-Dependent Hypertension.

BACKGROUND: Whether in volume-dependent primary hypertension, concentric left ventricular (LV) remodeling beyond hypertrophy (LVH) represents the impact of a pressure rather than a volume overload, is unclear. METHODS: Using central arterial pressure, and aortic velocity and diameter measurements in the outflow tract (echocardiography), we determined the factors that associate with concentric LVH or remodeling in a community of African ancestry (n = 709) with prevalent volume-dependent primary hypertension. RESULTS: Both left ventricular mass index (LVMI) and relative wall thickness (RWT) were positively and independently associated with end diastolic volume (EDV), stroke volume (SV), and peak aortic flow (Q) (P < 0.05 to <0.0001). However, neither LVMI nor RWT were positively and independently associated with systemic vascular resistance (SVR), or aortic characteristic impedance (Zc) or inversely associated with total arterial compliance (TAC). Consequently, both concentric (P < 0.0001) and eccentric (P < 0.0001) LVH were associated with similar increases in EDV, SV, and either office brachial, central arterial, or 24-hour blood pressures (BP), but neither increases in SVR or Zc nor decreases in TAC. LV RWT, but not LVMI was nevertheless independently and inversely associated with myocardial systolic function (midwall shortening and s') (P < 0.05 to <0.005) and decreases in LV systolic function were noted in concentric (P < 0.05), but not eccentric LVH. CONCLUSIONS: In volume-dependent primary hypertension, concentric LVH is determined as much by volume-dependent increases in systemic flow and an enhanced BP as eccentric LVH. Concentric remodeling nevertheless reflects decreases in systolic function beyond LVH.

Impact of stroke work on the ability of left ventricular mass to account for pressure effects on function in a community with prevalent systemic flow-dependent hypertension.

AIMS: To determine whether the confounding influence of stroke work on left ventricular mass (LVM) limits the ability of LVM to detect hypertensive LV dysfunction in systemic flow-dependent hypertension. METHODS: In a community with prevalent systemic flow-dependent hypertension (n = 709), arterial haemodynamics, LVM and LV function were determined using central arterial pressure, aortic velocity and diameter measurements in the outflow tract, and echocardiography with tissue Doppler imaging. RESULTS: In multivariate models, stroke work showed markedly stronger relations with LVM index (LVMI) than blood pressure load [central arterial SBP (SBPc), backward wave pressure (Pb), 24-h SBP] (P < 0.0001 for comparisons). In contrast, although SBPc, Pb, and 24-h SBP were inversely associated with myocardial tissue shortening (s') and lengthening (e') velocity, stroke work was not. With adjustments for stroke work, positive relationships between SBPc, Pb, or 24-h SBP and LVMI were eliminated (P = 0.20 to P = 0.89), but strong relations between BP and s', e' or E/e' (P = 0.009 to P < 0.0001) remained. In mediation analysis, stroke work fully accounted for BP effects on LVMI, but explained none of the effects of BP on LV function. Hence LVMI accounted for little of the impact of BP load on LV function. Although LVMI beyond stroke work (inappropriate LVM) improved on relations between LVMI and s', it failed to improve on relations with e' or E/e' and contributed little beyond LVMI to the impact of BP on LV function. CONCLUSION: In systemic flow-dependent hypertension, the impact of stroke work markedly limits the ability of LVM to account for adverse effects of hypertension on LV function.

Toxicological study of aqueous-methanol solvent fraction of methanol extract of Dacryodes edulis leaves.

Dacryodes edulis (G. Don) H.J. Lam) is the most popular species under the genus Dacryodes. It is well known for its nutritional and ethno-medicinal uses in South-eastern and South-western Nigeria. This study was aimed to evaluate the toxicity of the aqueous-methanol fraction of crude methanol extract of Dacryodes edulis leaves (AMDE). The test rats were randomized to groups of single oral treatment of AMDE (10-5000 mg/kgbw) for the acute toxicity study. They were monitored for obvious signs of behavioural change and mortality. For the subacute toxicity study, the rats were randomized to three daily treatment groups (of 200, 400 and 600 mg/kgbw of AMDE) for 28 days. The fourth group (control) received 2.5 %v/v DMSO. At the end of the experiment, blood samples were collected for hematology and clinical chemistry evaluation. The histopathology of the livers and kidneys were assessed using the excised organs. The cytotoxicity and genotoxicity of AMDE were also evaluated using Allium cepa model. The result showed that acute administration of AMDE, up to a dose of 5000 mg/kgbw did not result in mortality of the test rats. The observed median lethal dose (LD50) was greater than 5000 mg/kgbw. The subacute oral administration of AMDE for 28 days showed no significant (p > 0.05) effect on liver function, kidney function indices, organ - body weight ratio, but significantly (p < 0.05) decreased erythrocytic indices: red blood cells, haematocrit, and haemoglobin at 600 mg/kgbw. The Allium cepa assay revealed a non-significant reduction in mitotic index and low chromosomal aberrations of the treated groups. In conclusion, the aqueous-methanol solvent fraction of methanol extract of Dacryodes edulis leaves, AMDE is relatively safe. However, there are strong indications that it may contain compounds that are cytotoxic and reduces erythrocytic indices including red blood cells at high doses. Thus, adequate care should be taken in dosing and administering the extract to avert anaemic condition.

Investigation of cytotoxicity potential of different extracts of Ziziphus mauritiana (Lam) leaf Allium cepa model.

Previous studies showed that Ziziphus mauritiana is ethnomedicinally beneficial against various diseases, however the cytotoxic and genotoxic effects of this plant have not been well investigated. Therefore this study was undertaken to investigate cytotoxic and genotoxic effects of four different solvents extracts of Ziziphus mauritiana (Lam) leaf at different concentrations (20, 40, 60, 80, and 100 mg/L) using Allium cepa model. The cytotoxicity and genotoxicity parameters evaluated were mitotic index, root tip growth length and chromosomal aberration respectively. The result revealed a decrease in mitotic index percentage (%MI) and a dose dependent decrease in root tip length with increase in extracts concentration for all the extracts studied - with the ethanol extract showing the most significant effect in mitotic index. Furthermore, the effective concentrations (EC50) obtained were 81.30, 52.01, 90.68 and 112.30 mg/l for aqueous, ethanol, ethyl acetate and hexane extract respectively. Finally chromosomal aberrations such as vagrant chromosome, c-mitosis, bridged anaphase, sticky telophase were also observed in all four extracts and the percentage chromosomal aberration were observed to decrease with increased concentrations of extracts. Therefore based on the result obtained in this study it may be concluded that the plant (Ziziphus mauritiana (Lam)) extracts are cytotoxic and genotoxic in nature and the observed decrease in percentage chromosomal aberration may be as a result of antimutagenic bioactive principles present in the plant extracts. Hence care must be taken in its consumption and use in folk medicine.

Evaluation of the biosafety potentials of methanol extracts/fractions of Tapinanthus bangwensis and Moringa oleifera leaves using Allium cepa model.

Medicinal plants are considered two-edged swords. They are pharmacologically beneficial and sometimes toxic when abused. The health benefit of medicinal plant is due to their abundant phytochemical endowment. The present study is aimed at evaluating the biosafety potentials of methanol extracts/fractions of Tapinanthus bangwensis (T. bangwensis) and Moringa oleifera (M. oleifera) leaves using Allium cepa (A. cepa) model. Cytotoxicity assay was carried out by A. epa model. The cytotoxicity parameters studied were number of dividing cells, percentage mitotic index (% MI), root tip growth length and chromosomal aberrations. The phytochemistry was determined by UV-spectrophotometry while 2,2-diphenyl-1-picrylhydrazine (DPPH) and nitric oxide (NO) were used to assay antioxidant activity. The A. cepa assay result showed that the inhibitory effect of M. oleifera on root tip growth length was higher compared to T. bangwensis at 60-100mg/100ml concentrations. Decreased number of dividing cells and percentage mitotic index as concentrations increased observed indicate cytotoxicity however the acetone fractions were most cytotoxic. The frequently occurring chromosomal aberrations observed were vagrant, bridged, attached and sticky chromosomes while C-mitosis and binuclear chromosomes were not observed. Therefore cytotoxic effect was significant at 100mg/100ml. The phytochemical screening of methanol extracts/fractions of T. bangwensis and M. oleifera leaves revealed the presence of alkaloids, flavonoids, phenolics, saponins and tannins however saponins were significantly abundant in both plants compared to others. Alkaloid content was found to be low but was not detected in the acetone fractions of the plants. Methanol extracts/fractions of the plants' leaves exhibited antioxidant activities but was more prominent in the ethylacetate fraction of T. bangwensis and acetone fraction of M. oleifera. In conclusion, administration at 100mg/100ml could be unsafe for the biological system.

Hemodynamic Determinants of Age Versus Left Ventricular Diastolic Function Relations Across the Full Adult Age Range.

The relative contribution of loading conditions at different ages across the full adult lifespan to decreases in left ventricular (LV) diastolic function is unclear. Using central arterial pressure and aortic velocity and diameter measurements in the outflow tract, we determined the contribution of systemic vascular resistance, compression wave pressures (characteristic impedance [Zc]×aortic flow [Q], [PQ×Zc]) and backward wave pressures (Pb) to LV diastolic function (echocardiography) in a community sample across the full adult lifespan (n=605). Starting from early adulthood, stepwise age-related increases in LV filling pressures (E/e') and decreases in myocardial relaxation (e') were noted (P<0.0001). Before 50 years of age, before when PQ×Zc positively correlates with age, Pb, but not systemic vascular resistance was independently associated with LV mass index (P<0.002), E/e' (P<0.002), and e' (P<0.05). Moreover, in those over 50 years of age, when PQ×Zc positively correlates with age, again Pb, but neither PQxZc nor systemic vascular resistance was independently associated with LV mass index (P<0.01), E/e' (P<0.001), and e' (P<0.001). The contribution of Pb to age-related decreases in LV diastolic function was as strong in those younger as compared with older than 50 years of age and poorly indexed by brachial BP. In conclusion, a striking age-related deterioration in LV diastolic function begins at an early adult age and Pb is the dominant hemodynamic factor that accounts for this relationship. Age-related increases in Pb in young adults contribute as much to functional abnormalities ultimately responsible for LV diastolic dysfunction in hypertension as at an older age, effects poorly indexed by brachial BP.

In vitro and in vivo anti-diabetic and anti-oxidant activities of methanolic leaf extracts of Ocimum canum.

BACKGROUND: Diabetes is a metabolic disorder with a highly complex, multifaceted and intricate etiologies and thus may require management options that proffers multimodal mechanism of action. This present study evaluated the antidiabetic and antioxidant potential of the methanolic extract/fractions of leaves of Ocimum canum. METHODS: The antidiabetic potential was evaluated and using STZ-induced diabetic Wistar rat model (in vivo) and inhibition of α-amylase and α-glucosidase activity (in vitro). Antioxidant activity was assessed in vitro by free radical scavenging and reducing power assays and in vivo via monitoring SOD and CAT activities; GSH and MDA levels. RESULTS: The total phenolic content (221.0±3.0 mg catechol/g of sample) and tannins (146.0±4.0 mg tannic acid/g of sample) of the crude extract; and flavonoid of the aqueous-methanol fraction (216.0.0±1.0 mg of rutin/g of sample) were found to be significantly higher relative to others. The crude extract and the aqueous-methanol fraction exhibited a significantly (p<0.05) higher percentage reduction in fasting blood glucose and a concomitant increase in serum insulin level relative to the diabetic control group. The highest radical scavenging activity and reducing power were observed in the aqueous-methanol fraction. The aqueous-methanol solvent fraction also significantly reversed the alterations in oxidative stress markers occasioned by the diabetic condition. CONCLUSION: In conclusion, the result of the present study has demonstrated evidently that extracts of Ocimum canum leaves ameliorates hyperglycemia and the associated oxidative stress in STZ-induced rats.

Methanol-Extract/Fractions of Dacryodes edulis Leaves Ameliorate Hyperglycemia and Associated Oxidative Stress in Streptozotocin-Induced Diabetic Wistar Rats.

The present study evaluated the antidiabetic and antioxidant potential of the methanolic extract/solvent fractions of the leaves of Dacryodes edulis using a streptozotocin (STZ)-induced diabetic Albino Wistar rat model. The fasting blood glucose/insulin levels and inhibition of α-amylase and α-glucosidase were determined. Antioxidant activity was assessed in vitro by 2,2-diphenyl-1-picrylhydrazyl, hydroxyl, superoxide scavenging, reducing power, and total antioxidant capacity assays and in vivo by monitoring catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities and reduced glutathione (GSH) and malondialdehyde (MDA) levels. The aqueous-methanol fraction exhibited the highest and significant ( P < .05) reduction in fasting blood glucose (FBG; 54.03%) with a concomitant inhibition of α-amylase and α-glucosidase activities. The ethyl acetate fraction also exhibited a significant ( P < .05) reduction in FBG and an increase in insulin levels in the treated diabetic Wistar rats. A significantly ( P < .05) higher reducing power and radical scavenging activity was observed in the aqueous-methanol and ethyl acetate fractions. The aqueous-methanol and ethyl acetate fractions also significantly ( P < .05) reversed the alterations in oxidative stress markers (GSH, MDA, CAT, and SOD) observed in the diabetic control group. In conclusion, the study demonstrated that the methanol extract of Dacryodes edulis ameliorates hyperglycemia and the associated oxidative stress in STZ-induced diabetic Wistar rats. These observed activities are largely due to the compounds that partitions into the aqueous-methanol (55:45) solvent fraction. This provides scientific evidence for the use of this plant extract in folk medicine and also a baseline data for its further characterization. Further work should be carried out to characterize the aqueous-methanol solvent fractions for the active compounds.

Limited contribution of left ventricular mass and remodelling to the impact of blood pressure on diastolic function in a community sample.

AIMS: Although the development of left ventricular (LV) dysfunction in hypertension has traditionally been viewed as a transition process from a phase of structural LV remodelling to dysfunction, the extent to which LV mass (LVM) and remodelling account for blood pressure (BP)-associated alterations in LV diastolic function is uncertain. In product of coefficient mediation analysis, we aimed to determine the extent to which LVM index (LVMI) or relative wall thickness (RWT) account for relations between BP and LV diastolic function. METHODS: In 709 randomly selected participants from a community sample with a high prevalence of hypertension (49.6%), we determined BP and LVMI, RWT and several indices of diastolic function from transmitral blood flow and myocardial tissue Doppler (E/A, e'/a', e' and E/e') and left atrial volume using standard echocardiographic techniques. RESULTS: With adjustments for confounders, LVMI (P < 0.001-0.0001) and RWT (P < 0.05-0.001) were independently associated with E/A, e'/a', e' and E/e'. However, in product of coefficient mediation analysis, LVM and RWT failed to account for most BP-associated changes in diastolic function. Indeed, whilst a one SD increase in DBP or SBP (13 and 22 mmHg, respectively) translated into a 0.07, 0.13 and 0.53 decrease in E/A, e'/a', e' and a 0.73 increase in E/e', respectively, in mediation analysis LVMI accounted for only 0.0005, 0.0017, 0.05 and 0.08 of the impact of a one SD effect of LVMI on E/A, e'/a', e' and E/e', respectively. Similar contributions of RWT as for LVMI to BP-associated LV diastolic functional changes were noted and the contribution of LVMI or RWT to BP-related alterations in diastolic function was similar in those participants not receiving antihypertensive therapy. CONCLUSION: Although structural LV remodelling is independently associated with changes in LV diastolic function, LVMI and RWT account for only a minor proportion of the impact of BP on diastolic function. Thus, most BP-associated decreases in LV diastolic function are likely to be a transition process independent of LV hypertrophy or concentric remodelling.

Limited contribution of insulin resistance and metabolic parameters to obesity-associated increases in ambulatory blood pressure in a black African community.

Although accounting for a striking proportion of obesity effects on blood pressure (BP) in other populations, the extent to which obesity-associated increases in BP are explained by insulin resistance and metabolic changes in populations of African ancestry is uncertain. We determined the contribution of insulin resistance and associated metabolic abnormalities to variations in office or ambulatory BP in a black African community with prevalent obesity and hypertension. In 1225 randomly selected participants of black South African ancestry (age>16years, 43.1% obese, 47.4% abdominal obesity), we assessed adiposity indexes, the homeostasis model of insulin resistance (HOMA-IR) and associated metabolic abnormalities and office or ambulatory (n â€‹= â€‹798) BP. In separate models, waist circumference (p â€‹< â€‹0.0005-<0.0001) and HOMA-IR (p â€‹< â€‹0.51-0.005), were independently associated with office, 24 â€‹h, day or night systolic (SBP) or diastolic (DBP) BP. However, whilst a one standard deviation increase in waist circumference translated into a 1.47-3.08 â€‹mm Hg increased in office, 24-h SBP or DBP, in mediation analysis HOMA-IR accounted for only 0.12-0.30 â€‹mm Hg of the impact of a one standard deviation effect of waist circumference on office, and 24-h SBP and 0.003-0.17 â€‹mm Hg of the impact of a one standard deviation effect of waist circumference on office and 24-h DBP. In conclusion, in a black African community, insulin resistance accounts for a negligible proportion of the impact of obesity on office or ambulatory BP.

Insulin resistance influences the impact of hypertension on left ventricular diastolic dysfunction in a community sample.

BACKGROUND: Although obesity-associated metabolic abnormalities (insulin resistance-IR) may not play as marked a role in determining left ventricular (LV) diastolic dysfunction (DD) as hypertension, the impact of combinations of these risk factors on DD is unknown. HYPOTHESIS: We hypothesized that IR influences the impact of hypertension on DD. METHODS: In 704 randomly selected participants from a community sample with a high prevalence of hypertension (50.6%) and obesity (46.5%), we determined adiposity indices, IR from the homeostasis model (HOMA-IR) and LV diastolic function using standard echocardiographic techniques. RESULTS: HOMA-IR was independently associated with lateral wall e' and E/e' (P < 0.05 to P < 0.005) as well as a diagnosis of DD (P < 0.02). Importantly, however, an enhanced relationship between HOMA-IR and E/e' in hypertensives (n = 356, partial r = 0.15, P < 0.005) as compared to normotensives (n = 348, partial r = 0.02 P = 0.75) was noted. Consequently, as compared to normotensives, with adjustments for confounders, hypertension was independently associated with DD only in those with the highest tertile of HOMA-IR (odds ratio = 2.65, 95% confidence interval = 1.29-5.42, P < 0.01), while in those with the lowest tertile of HOMA-IR, hypertension failed to show a higher prevalence of DD (P = 0.22). CONCLUSIONS: Insulin resistance enhances the impact of hypertension on LV DD. Thus, DD is more likely to occur with the combination of hypertension and IR.

Limited Impact of ß-Adrenergic Receptor Activation on Left Ventricular Diastolic Function in Rat Models of Hypertensive Heart Disease.

BACKGROUND: Hypertension is a major cause of left ventricular (LV) diastolic dysfunction. Although ß-adrenergic receptor (ß-AR) blockers are often used to manage hypertension, the impact of ß-AR activation on LV lusitropic effects and hence filling pressures in the hypertensive heart with LV diastolic dysfunction is uncertain. METHODS: Using tissue Doppler imaging and Speckle tracking software, we assessed LV function in isoflurane anesthetised spontaneously hypertensive (SHR) and Dahl salt-sensitive (DSS) rats before and after ß-AR activation [isoproterenol (ISO) administration]. RESULTS: As compared to normotensive Wistar Kyoto control rats, or DSS rats not receiving NaCl in the drinking water, SHR and DSS rats receiving NaCl in the drinking water had a reduced myocardial relaxation as indexed by lateral wall e' (early diastolic tissue velocity at the level of the mitral annulus) and an increased LV filling pressure as indexed by E/e'. However, LV ejection fraction and deformation and motion were preserved in both SHR and DSS rats. The administration of ISO resulted in a marked increase in ejection fraction and decrease in LV filling volumes in all groups, and an increase in e' in SHR, but not DSS rats. However, after ISO administration, although E/e' decreased in DSS rats in association with a reduced filling volume, E/e' in SHR remained unchanged and SHR retained greater values than Wistar Kyoto control. CONCLUSIONS: The hypertensive heart is characterized by reductions in myocardial relaxation and increases in filling pressures, but ß-AR activation may fail to improve myocardial relaxation and when this occurs, it does not reduce LV filling pressures.

Immunoreactivity for calretininin interneurons of the hippocampal CA1 field and dentate gyrus in adult rats after administration of habanero peppers (Capsicum chinense Jacq.).

Calretinin (CR), a calcium-binding protein from EF-hand family, is localised in non-pyramidal GABA-ergic interneurons of the hippocampus. CR takes part in maintaining calcium binding homeostasis, which suggests its neuroprotective role. Hippocampal neurons contain membrane transient receptor potential vanilloid 1 (TRPV1) which binds to capsaicin (CAP) contained in habanero pepper fruits. Few in vivo studies have revealed the effect of CAP on interneurons containing CR. The aim of the present study was to investigate the CR immunoreac- tivity in interneurons of the hippocampal CA1 field and dentate gyrus (DG) in adult rats after intragastric admin- istration of the habanero pepper fruits. Wistar rats received a peanut oil - control group (C), and oil suspension of habanero pepper fruits at doses of 0.025 g dm/kg b.w. - group I and 0.08 g dm/kg b.w. - group II for 28 days. After euthanasia, the brains were collected and embedded in paraffin blocks using a routine histological tech- nique. Frontal hippocampal sections were immunohistochemically stained for CR by using a peroxidase-antiper- oxidase method. CR immunoreactive (CR-IR) interneurons were morphologically and morphometrically ana- lyzed under a light microscope. The results showed similar shapes and distribution of cells in both areas of the brain in group C and I of animals. However, CR-IR interneurons in the hippocampal CA1 field and in DG were occasionally observed in the group II of rats. The results of morphometric studies did not reveal statistically significant differences in the surface area and shape index of cells between examined brain regions from groups I and II compared to group C. Only in group II of rats, an increase in the digital immunostaining intensity of CR-IR interneurons was found in DG. Low number of CR-IR interneurons in the hippocampal CA1 field and in the DG, under the influence of a large dose of habanero pepper fruits containing CAP, may be caused by the activation of TRPV1 receptors and the increase in Ca2+ ions in these cells. This phenomenon may ultimately lead to neuronal death and may disturb neuronal conduction.

Effects of maternal treatment with ß-hydroxy-ß-metylbutyrate and 2-oxoglutaric acid on femur development in offspring of minks of the standard dark brown type.

The aim of the study was to evaluate the effect of the diet, mother type and sex of the offspring on the mechanical and geometric parameters of long bones as well as bone tissue density in minks. Primiparous and multiparous dams were supplemented with ß-hydroxy ß-methylbutyrate (a metabolite of leucine, at the daily dosage of 0.02 g/kg of body weight) and/or 2-oxoglutaric acid (a precursor of glutamine, at the daily dosage of 0.4 g/kg of body weight) during gestation. The diet did not influence bone tissue density and the length of the humerus. An increase in the length of the femur was noted in male offspring delivered by multiparous dams. The diet resulted in an increase in the weight of the humerus in males from multiparous dams and a decrease in offspring from primiparous dams. Heavier femora were noted in male offspring delivered by both types of dams. The maximum elastic strength of the humerus was higher in the offspring delivered by multiparous than primiparous dams, irrespective of the offspring sex. The diet resulted in reduction in the ultimate strength of the femur in the male offspring delivered by primiparous dams. Only females born by multiparous dams, irrespective of the diet, showed a significant increase in the cross-sectional area of the humerus, while a significant decline was noted in males delivered by multiparous dams and in all the offspring delivered by primiparous dams. An increase in the cross-sectional area of the femur was noted in the offspring delivered by multiparous dams, while reduction was observed in the offspring delivered by primiparous dams. These results have shown for the first time that the presence of ß-hydroxy-ß-methylbutyrate or 2-oxoglutaric acid in the diet of pregnant primiparous or multiparous dams unambiguously affects the geometry and mechanical properties of offspring's long bones.

Immunoreactivity of arcuate nucleus astrocytes in rats after intragastric administration of habanero peppers (Capsicum Chinese Jacq.).

Habanero pepper fruits contain capsaicin (CAP) characterised by a spicy taste. Astrocytes express vanilloid receptor (TRPV1), which interacts with cannabinoids including CAP. Only a few studies revealed that CAP leads to alterations of the arcuate nucleus (ARC) structures. The aim of this study was to analyse the GFAP (GFAP-IR) and S100ß (S100ß-IR) immunoreactive astrocytes of ARC in adult rats after intragastric administration of habanero pepper fruits. Adult, Wistar rats received a peanut oil - control group (C) - and oil suspension of habanero pepper fruits at a dose of 0.08 g dm/kg b.w. for 7 days - E1 group - and 28 days - E2 group. After euthanasia, the brains were embedded in paraffin blocks using a routine histological technique. Frontal slices of ARC were immunohistochemically stained for GFAP and S100ß using specific antibodies in the peroxidase-antiperoxidase method. Astrocytes of ARC were morphologically and morphometrically analysed under a light microscope. The results of the study did not reveal statistically significant changes in the density of GFAP-IR cells in E1 and E2 groups of rats in comparison with group C. A statistically significant increase in the density of S100ß-IR astrocytes was observed in the E1 group and a decrease in the E2 group. Astrocytes with expression of both studied proteins were characterised by morphological alterations in ARC in the E2 group. The obtained results suggest an influence of CAP contained in habanero pepper fruits on the reactivity of astroglia, which may have an impact on the astrocyte-neuron interactions in order to maintain a proper activity of nervous cells in ARC.

Immunohistochemical evaluation of hippocampal CA1 region astrocytes in 10-day-old rats after monosodium glutamate treatment.

High concentration of glutamate (Glu) is excitotoxic for nervous system structures. This may lead to glial reactivity ie. increased expression of glial fibrillary acidic protein (GFAP) and S100ß protein, and also to hypertrophy and proliferation of cells which are determined by the presence of Ki-67 antigen. The aim of the study was to analyse the immunoreactivity of the GFAP, S100ß and Ki-67 proteins in astrocytes of hippocampal CA1 region in young rats after administration of monosodium glutamate (MSG) at two doses: 2 g/kg b.w. (I group) and 4 g/kg b.w. (II group). In rats from I and II group morphologically altered astrocytes with the GFAP expression were observed in the SLM of the hippocampal CA1 region. The cells had eccentrically located nuclei and on the opposite site of the nuclei there were single or double, long and weakly branched processes. Moreover, in the SLM the increase of the number of GFAP and S100ß immunopositive astrocytes and nuclei with Ki-67 expression, in contrary to control individuals, was observed. These results suggest the increased expression of the proteins in early reactions or hyperplasia which, together with cell hypertrophy, indicate late reactivity of astroglia in response to glutamate noxious effect.

Characterization of field and vaccine infectious bursal disease viruses from Nigeria revealing possible virulence and regional markers in the VP2 minor hydrophilic peaks.

Outbreaks of infectious bursal disease in vaccinated chicken flocks are frequent in Nigeria. For the control of infectious bursal disease, live vaccines based on foreign infectious bursal disease virus (IBDV) strains are used. The present study investigated the phylogenetic relationship between field and vaccine IBDV strains from northwestern Nigeria. Thirty field IBDV strains and three commercial vaccines strains were characterized through sequencing the VP2 hypervariable region. In addition, the complete genome segment A coding region for two vaccines and two field strains was sequenced. The deduced amino acid sequences (position 212 to 331) of IBDV strains from Nigeria and other regions of the world were aligned and possible regional and virulence markers were identified associated with VP2 minor hydrophilic peaks. Reversion to virulence of a vaccine strain with a Q to L mutation at position 253 was observed. Phylogenetic analyses revealed a unique cluster of northwest Nigerian field IBDV strains alone or related to imported characterized classical and very virulent IBDV vaccines. The results suggest that when IBDV strains spread from their region of origin to a different region they mutate alongside indigenous field strains but may retain their identity on the VP2 region.