Azadirachta indica extract–artesunic acid combination produces an increased cure rate of Plasmodium berghei-infected mice

Context: Available artemisinin-combination therapies (ACTs) are expensive. Various traditional herbal remedies for malaria involve plants, proven scientifically to have antiplasmodial effects, e.g., Azadirachta indica A. Juss. (Meliaceae).

Objective: Combination of an artemisinin-based compound and a medicinal herb extract will provide an indigenous alternative/herb-based ACT.

Materials and methods: The in vivo schizontocidal activity of the crude aqueous extract of 100, 500, and 1000?mg/kg of A. indica fresh leaves (NCE) and 6, 15, and 20?mg/kg of artesunic acid were determined, alone and in combination, while keeping the dose of artesunic acid constant at 15?mg/kg, using the Peter’s 4-day suppressive test and Swiss albino mice. The ED₅₀ was calculated from the dose-response relationships. Percentage survival and cure were also determined.

Results: The average yield of two extractions of NCE was 8.33?±?1.67%. Combination of 1000?mg/kg of NCE and 15?mg/kg of artesunic acid, produced a significant reduction of parasitemia (96.87%), compared to 20?mg/kg of artesunic acid alone (68.14%). The combination had an ED₅₀ of 0.58?mg/kg while that of artesunic acid alone was 8.814?mg/kg. The combinations of NCE with artesunic acid produced a cure, although the artesunic acid did not produce a cure in 30?d.

Discussion: NCE increased the activity of artesunic acid in terms of reduction in parasitemia, and increased survival time and cure rate.

Conclusion: The combination of an artemisinin and aqueous extract of neem leaf is possible, providing a potentiated reduction of parasitemia, and increased cure rate.     

Risk indicators for the presence and extent of root caries among caries-active adults enrolled in the Xylitol for Adult Caries Trial (X-ACT)

Objective

This paper uses baseline data from a randomized clinical trial to evaluate cross-sectional indicators of root caries in caries-active adults.

Materials and methods

Adults (21–80?years) having at least 12 erupted teeth and between one and ten caries lesions were enrolled. Participants (n?=?437) received caries exams by trained, calibrated examiners and responded to baseline demographic and medical–dental questionnaires. We examined associations between baseline characteristics and (1) the presence of any root caries using Mantel–Haenszel hypothesis tests and odds ratio (OR) estimators and (2) the number of root surfaces with caries among study participants with exposed root surfaces (n?=?349) using Mantel–Haenszel mean score tests and Mann–Whitney estimators.

Results/conclusions

Adjusting for study site and age, male gender [OR, 1.72; 95% confidence interval (CI), 1.08, 2.78], white race (OR, 2.39; 95% CI, 1.43, 3.98), recent dental visit (OR, 1.98; 95% CI, 1.07, 3.66), poor self-described oral health (OR, 2.65; 95% CI, 1.10, 6.39), and recent professional fluoride treatment (OR, 1.85; 95% CI, 1.06, 3.25) were significantly associated with increased odds to have any root caries, and study participants with exposed root surfaces characterized by male gender [Mann–Whitney probability estimate (MW)?=?0.57; 95% CI, 0.51, 0.63), white race (MW, 0.61; 0.55, 0.68), recent dental visit (MW, 0.58; 0.50, 0.67), poor self-described oral health (MW, 0.61; 0.53, 0.69), and flossing at least once per day (MW, 0.57; 95% CI, 0.51, 0.62) were significantly more likely to have a greater number of root surfaces with caries than a randomly selected study participant from their respective complementary subgroups (female gender, non-white, etc.).

Clinical relevance

Our findings may help identify individuals at higher root caries risk.     

Eroded enamel lesion remineralization by saliva as a possible factor in the site-specificity of human dental erosion

The composition and flow of saliva, which determine its functions, vary within intraoral sites and among individuals. Also, the susceptibility to tooth erosion reportedly varies among individuals and within the dental arches. A possible effect of saliva on early-eroded lesions may be a contributory factor. The aims here were firstly to determine the remineralization of eroded enamel lesions by saliva, and secondly to investigate any variation of this remineralization within the dental arches and among individuals. Early enamel erosion was produced on human premolars using orange juice. Control sections and two test slabs were cut from each tooth. The two slabs from the same lesion were bonded with composite resins to the palatal surface of upper right lateral incisor teeth and the lingual surface of the lower right lateral incisor teeth of volunteers, who then chewed a sugar-free gum four times daily. After 28-day intraoral exposure, mineral loss (DeltaZ) and lesion depth (ld) were quantified using microradiography and the data analysed by paired t-test (n=10, alpha=0.05). Mean DeltaZ was significantly lower in the group of slabs positioned palatally (P<0.001) and lingually (P<0.001) when compared with the control group, and in the lingually placed group when compared with the palatally positioned (P<0.01). A significantly lower ld was observed in the group of slabs positioned palatally (P<0.05) and lingually (P<0.001) when compared with the control group, and in the lingually positioned group when compared with the palatally placed (P<0.05). It was concluded that saliva can remineralize early enamel erosion, and that the degree of remineralization varies within intraoral sites and may be responsible for the differing susceptibility to erosion within the dental arches.     

Factors influencing the development of dental erosion in vitro: enamel type, temperature and exposure time

The influence of temperature, duration of exposure, and enamel type on the development and progression of dental erosion has been determined. Three experiments were devised as follows. Eroded lesions were produced on enamel samples with orange juice: (1) at different temperatures; (2) for different lengths of time; and (3) on bovine permanent, human deciduous and human permanent enamel. Lesion parameters (mineral loss and lesion depth) were quantified using transverse microradiography. Both lesion parameters were significantly lower at 4 degrees C when compared with 20 degrees C and 37 degrees C, and at 20 degrees C when compared with 37 degrees C. Lesion parameters increased significantly as the length of exposure increased, and were positively correlated (r=0.98, P<0.05) to the exposure time. Both parameters were significantly greater in bovine enamel than human permanent and deciduous enamel, and in human deciduous than permanent enamel. Lesion progression, as measured by mineral loss, was in the ratio 2.0:1.5:1.0 for bovine:human deciduous:human permanent, and by lesion depth, 1.7:1. 3:1.0. In conclusion, the erosiveness of orange juice was less pronounced at a lower temperature, and increased with an increased exposure time. Erosion progressed twice as fast in bovine permanent than in human permanent enamel, and 1.5 times more rapidly in human deciduous than in permanent enamel.     

Monitoring bacterial-demineralization of human dentine by electrochemical impedance spectroscopy

Objective

The purpose of this study was two-fold: (1) to monitor bacterial biofilm formation and bacteria-induced demineralization of dentine in situ by using electrochemical impedance spectrum (EIS); (2) to examine the relationship between EIS findings and changes in the chemical composition and ultrastructure of dentine during bacteria-induced demineralization.

Methods

In this study, dentine demineralization was induced by Streptococcusmutans (ATCC 25175) in the presence of sucrose in culture medium and was monitored using two EIS measurement systems (Type A with a working electrode and Type B without a working electrode). Scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) were employed to examine the morphology, element contents and crystallinity of hydroxyapatite (HAP) on the dentine surface. Transverse microradiography (TMR) was used to characterize the lesion depth and degree of mineral loss during demineralization.

Results

The resistance of the bulk dentine (R_d) and the apparent resistance of dentine (R_a) measured from the Type A and Type B EIS systems, respectively, decreased gradually with demineralization. The resistance of the biofilm formed on dentine surface was determined by fitting the EIS data with equivalent circuits. The presence of biofilm slightly increased R_a of dentine before demineralization. However, the electrochemical behavior of biofilm did not affect the decreasing impedance of dentine with demineralization. The SEM, EDX, XRD and TMR results demonstrated that the surface and bulk dentine gradually became more porous due to the loss of minerals during demineralization, which in turn resulted in the decrease in R_d and R_a values obtained from EIS systems.

Conclusions

This investigation highlighted EIS as a potential technique to monitor biofilm formation and bacterial-induced demineralization in situ.     

Awareness and practice of contraception among female students at the Institute of Management and Technology (IMT), Enugu.

A study of the knowledge, attitudes to and practice of contraception among the female students at the Institute of Management and Technology (IMT), Enugu, was carried out, involving 266 female students out of a total female student population of 1,510. The mean age of the population sample was 19.1 years and 254 (95%) were single. Ninety-six percent were aware of the availability of contraceptives. Knowledge relating to the practice of contraception was superficial since as many as 61% of the objectors believed that contraception subsequently led to infertility. One hundred and thirty (49%) of the studied population had used one form of contraception or another sometime in their lives. Seventy-six percent had not used any contraception for initial intercourse. The rhythm method followed by the barrier method were the most popular forms of contraception. Practice of contraception by the studied population was inconsistent as 21% of the students eventually had an unwanted pregnancy and 18% had an induced abortion. Health education is strongly recommended to our women folk in order to reduce the high incidence of unwanted pregnancy and its associated medical and social complications.