Kolaviron pre-treatment suppresses 7, 12 dimethylbenzanthracene-induced alterations in estrogen receptor-α, CYP 1A1, oxidative stress and inflammation in female Wistar rats.

Due to the need to develop locally available, cheaper, and efficacious treatment regimens for breast cancer, the chemopreventive effect of kolaviron (KV), an extract of Garcinia kola seeds was examined. Fifty (50) female Wistar rats (120-180 g) were assigned to five groups (control group, 7, 12 dimethylbenzanthracene [DMBA] groups, tamoxifen group) of 10 rats each. They were pre-treated with KV thrice a week for four weeks except control. Estrogen receptor-α (ER-α) levels were determined in the pre-treated rats before induction of mammary carcinogenesis. After the four weeks pre-treatment period, 80 mg/kg of DMBA was used for induction. A hundred and fifty (150) days after induction, the rats were sacrificed humanely. Significantly higher levels of ER-α, formation of lobular neoplastic cells, epithelial hyperplasia, lymphocyte infiltration, increased cytokines (interleukin-6 [IL-6] and tumor necrosis factor-α [TNF-α]), CYP1A1 activity and malondialdehyde (MDA) with a corresponding decrease in superoxide dismutase (SOD), catalase and glutathione peroxidase were observed in DMBA-induced rats. Pre-treatment with KV at 200 mg/kg body weight significantly (p < .05) decreased ER-α levels by 19.01% and 37.52%, [IL-6] by 36.37% and 20.55%, TNF-α by 42.2% and 12.33% in serum and mammary tissue respectively. Also, a significant (p < .05) decrease in serum CYP1A1 activity, MDA with concomitant increase in SOD, catalase and glutathione peroxidase activities were observed in serum and mammary tissue respectively. Collectively, the results suggest that KV could be further explored in targeting chemoprevention of DMBA-induced mammary damage. PRACTICAL APPLICATIONS: Garcinia kola is widely cultivated in West and Central Africa with kolaviron (KV) as its major constituents. The seeds which have a bitter astringent taste are widely consumed by people in the region. Locals claim that consumption of the seeds provides relief for the management of several ailments including cancer. However, scientific investigations that provide a basis for these claims are still needed. This study provides evidence that points to the ameliorative potential of KV on breast cancer model. The results will be beneficial to local communities who hitherto had no knowledge on the potential of G. kola in chemoprevention. The results from this study will also attract further research attention from the international scientific community to examine the anti-cancer benefits of G. kola. This will also be beneficial to the global community due to the increasing number of breast cancer cases recorded annually.

Studies on effects of lactose on experimental Trypanosoma vivax infection in Zebu cattle. 1. Plasma kinetics of intravenously administered lactose at onset of infection and pathology.

Lactose in normal saline was administered intravenously to a group of Zebu cattle infected with Trypanosoma vivax to determine the blood plasma kinetics at onset of an experimental infection and its ability to protect tissues against damage as part of preliminary studies to determine its suitability for use in the treatment of trypanosomosis. Significantly (P < 0.01) higher lactose concentrations were observed in the T. vivax-infected bulls at 30 min and 1 h (P < 0.05) post-infection (p.i.) and by 4 h p.i. the plasma lactose remained above the level prior to infusion, after which it fell slightly below the pre-infusion level in the uninfected group. Calculated pharmacokinetic parameters revealed delayed excretion of lactose in the T. vivax-infected group soon after infection. The total body clearance (Cl(B)) was significantly (P < 0.05) reduced. The biological half-life (t1/2), elimination rate constant (k(el)) and apparent volume of distribution (V(d)) were relatively decreased (P > 0.05) as a result of the T. vivax infection. Retention of lactose in the plasma was attributed to decreased plasma clearance. It is suggested that the presence of trypanosomes in circulation rather than organic lesions could have been responsible for the delay observed in the excretion of lactose. At 12 weeks p.i., when the experiment was terminated, the group infected and given lactose infusion (despite higher parasitaemia) had no gross or histopathological lesions in the brain, spleen, lymph nodes, heart, kidneys, liver and testes. However, the group infected but not infused with lactose were emaciated, had pale mucosae, watery blood, general muscular atrophy, serous atrophy of coronary fat and other adipose tissue, hepatomegaly, splenomegaly, swollen and oedematous lymph nodes, all of which are suggestive of trypanosomosis. Histopathological lesions included narrowing of Bowman's space and hypercellularity of glomerular tufts in the kidneys with the mean glomerular tuft nuclear indices (GTNs) in the group significantly higher (P < 0.01) than the mean GTNs of the lactose-infused and control bulls. Degenerative changes occurred in the myocardium, spleen, testes and epididymides. The tesicular and epididymal lesions are indicative of male reproductive dysfunction.

Studies on effects of lactose on experimental Trypanosoma vivax infection in Zebu cattle. 2. Packed cell volume.

The ability of intravenously administered lactose in normal saline to prevent a decline in packed cell volume (PCV) during experimental trypanosomosis was studied in Zebu cattle. During the lactose infusion period, the PCV was stable up to Day 5 post-infection (p.i.) in a lactose-infused group, compared to that in an uninfused group in which the PCV dropped significantly (P < 0.05) as shown by the values of cumulative percentage change. Furthermore the mean rate of change in PCV was significantly (P < 0.05) higher in the uninfused group relative to the lactose-infused group during the same period. While the PCV fell markedly in the lactose-infused group a day after lactose infusion was stopped (Day 13 p.i.), subsequent PCV values were significantly (P < 0.05) higher compared to those in the uninfused group, up to the end of experiment on Day 17 p.i. However the mean rates of change in PCV did not vary significantly (P > 0.05) between the groups during the period in which lactose infusion was stopped. The mean levels of parasitaemic waves and parasitaemia were higher, more prolonged and more frequent in the lactose-infused group. It was inferred that the lactose was able to prevent an early onset of anaemia in the Trypanosoma vivax-infected Zebu cattle.

Effect of Insulin on Visuo-Spatial Memory and Histology of Cerebral Cortex in the Presence or Absence of Nitric Oxide Inhibition.

Insulin has emerged from its traditional 'peripheral' glucose-lowering function to become increasingly regarded as a brain hormone that controls a wide range of functions including learning and memory. Insulin action on learning and memory is linked to nitric oxide (NO) signalling, but its effects on memory and histology of cerebral cortex in conditions of varied NO availability is unclear. This research sought to determine the effect of insulin on visuo-spatial learning, memory and histology of cerebral cortex during NO deficiency. Twenty-four mice weighing 21-23 g, were divided into four groups (n = 6) and treated daily for seven days with 0.2 ml distilled water subcutaneously (s.c.) (control), 10 I.U/kg insulin s.c., 10 I.U/kg insulin + 50 mg/kg L-NAME intraperitoneally (i.p.), and 50 mg/kg i.p. L-NAME s.c., respectively. The 3-day MWM paradigm was used to assess memory. Brain tissue was examined for histological changes. There was no significant difference between day 1 and day 2 latencies for all the groups. The mice in all (but L-NAME) groups spent more time in the target quadrant, and the difference was significant within but not between groups. There was significant reduction in number of platform site crossings (4.83 ± 0.5, 0.67 ± 0.3, 0.50 ± 0.3 and 0.50 ± 0.3 for control, insulin, insulin+L-NAME and L-NAME groups, respectively) in all the groups compared to control. Normal histology of the cortex and absence of histological lesions were observed in brain slides of control and treatment groups. It was concluded that insulin administration impairs visuo-spatial memory to a greater extent in the presence of NO block, and to a lesser extent in the absence of NO block. Nitric oxide has a role in insulin-induced memory impairment. Insulin administration in the presence or absence of NO block had no effect on histology of cortex.

Effects of combined parenteral vitamins C and E administration on the severity of anaemia, hepatic and renal damage in Trypanosoma brucei brucei infected rabbits.

Rabbits infected with Trypanosoma brucei brucei (Basa isolate) were intraperitoneally administered with vitamins C and E at 100 mg/kg and 10 mg/kg body weight, respectively, from day 7 before infection to day 12 post-infection (p.i.). Another group of rabbits were similarly infected, but received no vitamin treatment. The uninfected (control) rabbits were either untreated or treated with vitamins like the infected group. Treatment of the infected animals did not affect the onset and level of parasitaemia. On day 12 p.i., the anaemia tended to be ameliorated, but insignificantly, by the treatment. The infection increased (p<0.05) serum urea and creatinine concentrations to similar levels in treated and untreated groups. However, the increase (p<0.05) in alanine and aspartate transaminases in the untreated infected animals was prevented in the treated infected ones. Therefore, it seemed that the treatment with antioxidant vitamins boosted their storage in hepatic cells, but not in erythrocytes and glomeruli, to annul any cellular injury due to infection. It is concluded that this may be an indirect evidence that the hepatic damage may be principally due to oxidative injury.

Effect of acute Trypanosoma vivax infection on cattle erythrocyte glutathione and susceptibility to in vitro peroxidation.

During acute Trypanosoma vivax infection of calves, produced by intravenous inoculation, the mean packed cell volume and red blood cell counts of the infected animals decreased significantly (P < 0.05) between Days 6 and 13 post-infection (pi). The moderately severe normocytic anaemia started to develop during the first wave of parasitaemia which occurred from Day 2 pi and peaked between Days 4 and 5 pi. The mean erythrocyte glutathione (GSH) concentration of the infected calves decreased significantly (P < 0.05) from 58.4 +/- 11.4 mg 100ml-1 red blood cells (RBC) on Day 0 pi to 44.5 +/- 12.8 mg 100ml-1 RBC on Day 5 pi. As the GSH values recovered on Day 6 pi and increased thereafter, another slight decrease (P > 0.05) in GSH concentration occurred on Day 12 pi at the second peak of parasitaemia followed by a significant (P < 0.05) increase to 79.1 +/- 14.6 mg 100ml-1 RBC on Day 13 pi. In the uninfected calves, the mean GSH values ranged from 47.7 +/- 7.0 to 60.8 +/- 6.8 mg 100ml-1 RBC. When washed, erythrocytes of the infected and uninfected calves were separately challenged with hydrogen peroxide. They produced comparable amounts of thiobarbituric acid reactive substances as a measure of by-products of lipid peroxidation. This suggested that the ability of the erythrocytes to prevent peroxidative injury was not reduced, because GSH regeneration was probably enhanced and the antioxidant capacity of the erythrocytes was maintained.

Effects of acute bovine trypanosomosis (Trypanosoma vivax) on plasma kinetics of intravenously administered lactose.

Four calves infected with Trypanosoma vivax and four uninfected control calves were each injected intravenously with repeated doses of 0.5 g lactose kg-1 body weight, thrice daily at intervals of 4 h. Plasma samples were collected at specified time intervals and analysed for lactose. Pharmacokinetic parameters were calculated from the data. T. vivax infection delayed excretion of lactose from the body, thus leading to significantly (P < 0.001) increased biological half life (t1/2) and a significantly (P < 0.001) reduced elimination rate constant for lactose in the body. The apparent volume of distribution and total clearance of lactose were not affected by the infection. T. vivax infection also appeared to cause accumulation of lactose in the plasma after repeated intravenous administration.

Normal plasma lactose concentrations and kinetics of intravenously infused lactose in cattle.

Plasma lactose concentration and its kinetics were determined in apparently normal cattle, as a prelude to investigating its chemotherapeutic significance in bovine trypanosomiasis. It is hoped that intravenously administered lactose may be able to reduce the rate of sequestration of desialylated erythrocytes during Trypanosoma vivax infection of cattle; thus decreasing the rate of development of trypanosomal anaemia in infected animals. A range of 0.061 to 0.55 mM with a mean of 0.208 +/- 0.128 mM standard deviation (SD), observed in adult cattle was significantly lower (P<0.001) than corresponding values in recently weaned calves; 0.429 to 1.496 mM (0.972 +/- 0.318 mM). Semi-logarithmic plots from calves given a single dose (0.5 g lactose per kg bodyweight as a solution in normal saline, infused at the rate of 18 ml min(-1)) showed a biexponential pattern of regression lines. Decrease in plasma concentrations was biphasic and lactose was rapidly distributed into the extravascular space after administration. The biological half-life (t1/2) of the infused lactose ranged from 4.10 to 6.00 hours (5.01 +/- 0.81 hours); its mean elimination rate constant was 0.14 +/- 0.02 hour(-1), mean apparent volume of distribution was 168.09 +/- 56.65 ml kg(-1) while its mean total clearance was 23.54 +/- 8.31 ml kg(-1) hour(-1). A single dose rapidly reached a peak and gradually fell below the pre-infusion level while repeated doses did not cause accumulation of the lactose in the plasma as each infusion fell back to normal relatively rapidly.

Effects of vitamin E administration on Plasmodium berghei induced pathological changes and oxidative stress in mice.

The effects of daily intraperitoneal doses of 1000 i.u/kg body weight of vitamin E on the course of Plasmodium berghei NK 65 infection and the parasite-induced anemia as well as alterations in the relative weight of some selected organs and antioxidant status in mice were investigated. The number of parasitized red cells were not initially affected by the vitamin administration but were persistently lowered after 11th day post infection to the termination of the experiment. The P. berghei infection was found to induce anemia, significantly (P<0.05) increased the relative weight of liver, spleen and kidney but significantly decreased (P<0.05) the relative brain weight. However, all the parasite-induced changes in these parameters were significantly (P<0.05) ameliorated by the vitamin administration. Furthermore, malonydialdehyde concentration in the serum, liver and brain of infected animals was significantly (P<0.05) increased whereas superoxide dismutase and catalase activities were significantly (P<0.05) decreased by the infection. But vitamin E administration was found to, a significant degree (P<0.05), reversed the disease-induced alterations in these oxidative stress markers. It was concluded that vitamin E at the dose and route used prevented P. berghei induced anemia as well as alterations in relative organ weight and antioxidant status in mice.

Characterization of sialidase from bloodstream forms of Trypanosoma vivax.

Sialidase (EC: 3.2.1.18) from Trypanosoma vivax (Agari Strain) was isolated from bloodstream forms of the parasite and purified to apparent electrophoretic homogeneity. The enzyme was purified 77-fold with a yield of 32% and co-eluted as a 66-kDa protein from a Sephadex G 110 column. The T. vivax sialidase was optimally active at 37 degrees C with an activation energy (E(a)) of 26.2 kJ mole(-1). The pH activity profile was broad with optimal activity at 6.5. The enzyme was activated by dithiothreitol and strongly inhibited by para-hydroxy mercuricbenzoate thus implicating a sulfhydryl group as a possible active site residue of the enzyme. Theenzyme hydrolysed Neu5Ac2,3lac and fetuin. It was inactive towards Neu5Ac2,6lac, colomic acid and the gangliosides GM1, and GDI. Initial velocity studies, for the determination of kinetic constants with fetuin as substrate gave a V(max) of 142.86 micromol h(-1) mg(-1) and a K(M) of 0.45 mM. The K(M) and V(max) with Neu5Ac-2,3lac were 0.17 mM and 840 micromole h(-1) mg(-1) respectively. The T. vivax sialidase was inhibited competitively by both 2,3 dideoxy neuraminic acid (Neu5Ac2,3en) and para-hydroxy oxamic acid. When ghost RBCs were used as substrates, the enzyme desialylated the RBCs from camel, goat, and zebu bull. The RBCs from dog, mouse and ndama bull were resistant to hydrolysis.