RESUMEN
Background: The noise is considered as a factor of environmental stress, causing a wide range of health effects such as acoustic, cardiovascular, nervous and endocrine systems
Purpose: The present study was conducted to examine the affects of repeated exposure to noise on the peripheral auditory system, adrenal gland and heart tissue
Method: The White strain rats "Wistar" were exposed to chronic and repetitive exposure noise at two different intensity levels of 70 and 85dB [A]. The noise level was generated by the Audacity® software to an octave-band noise [8616 kHz]. The sound exposure duration was 6 hr/day, 5 days per week for 3 months. Quantitative and qualitative investigations were performed by using electron microscopy. The ganglion neuron counting was examined via light microscopy
Results: The results show that exposure to sound intensities 70 and 85 dB [A] for long periods, lead to changes in the morphological structure of the cochlea [inner ear], adrenal cortex and cardiac tissue which involve cell disruption which over time can lead to pathological effects
Conclusion: This study provides morphological evidence that repetitive exposure noise at moderate sound levels to 70 and 85 dB [A] induces changes in the peripheral auditory system, the adrenal cortex and heart tissue
RESUMEN
OBJECTIVE@#To investigate the antioxidant, antimicrobial, antiplasmodial, acute toxicity and haemolytic activities of methanolic extracts of three plants. Phytochemical analysis to determine the phenolic contents was also carried out.@*METHODS@#The 2,2-diphenyl-1-picryl-hydrazyl (DPPH) free radical scavenging, NCCLS broth microdilution and Plasmodium Lactate Dehydrogenase (pLDH) assays were used to determine antioxidant, antimicrobial and antiplasmodial activities, respectively. Haemolysis assay was conducted on A(+) human red blood cells and acute toxicity on male Swiss albino mice. Phenolics were quantitatively determined using spectrophotometric methods.@*RESULTS@#The DPPH assay yielded interesting antioxidant activities of methanolic extract of Parinari curatellifolia (P. curatellifolia) and Entada africana (E. africana) (IC(50) were 0.20±0.01 μg/mL and 0.47±0.01 μg/mL, respectively). This activity was highly correlated with phenolic contents of extracts. The antimicrobial tests displayed minimal inhibitory concentrations (MICs) values ranging from 0.90 to 1.80 mg/mL for Serratia marcescens (S. marcescens) the most susceptible bacterial strain. MIC value was 1.20 mg/mL for susceptible fungal strains including Mucor rouxi (M. rouxi), Fusarium oxyporum (F. oxyporum) and Rhizopus nigricans (R. nigricans). pLDH assay showed moderate antiplasmodial activity of Balanites aegyptiaca (B. aegyptiaca) (IC(50) = 24.56±3.45 μg/mL), however this extract was highly haemolytic and toxic in mice (LD(50) = 625±128 mg/kg).@*CONCLUSIONS@#Our results support in part the use of the selected plants in the treatment of microbial infections. In addition the plant showed interesting antioxidant activity that could be useful in the management of oxidative stress.