Morphological evaluation of the incisive canal with reference to gender and age: A cone-beam computed tomography study

Background

The incisive canal (IC) is an important anatomical structure in the premaxilla that should be considered during many dental procedures.

Aims

The objective of this study is to associate the IC morphology and dimensions with reference to gender and age by means of cone-beam computed tomography (CBCT).

Patients and Methods

A retrospective study was conducted using archived CBCT records of patients who sought treatment at the Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia. OnDemand 3D Imaging software was utilized in image reconstruction and measurement determination. The parameters evaluated were the IC shape and dimensions in a sagittal and coronal view at two levels: palatal opening and nasal opening. The variables were compared according to age and gender using one-way Analysis of Variance (ANOVA) and Kruskal Wallis tests. Confidence level was obtained at P < 0.05.

Results

Out of the 370 CBCT images assessed, only 100 images fulfilled the inclusion criteria; 50 males and 50 females. No substantial variance in IC shapes was found in both the sagittal and coronal perspectives with reference to age and gender. Likewise, there was no statistical variation in IC dimensions with reference to age. On the other hand, there was a statistical difference in IC length when correlated with gender as the male subjects had longer IC as compared to females (P < 0.01).

Conclusion

There is no association between IC morphology, age and gender. However, substantial variation in IC length was observed between genders.

Learning anatomy before and during COVID-19 pandemic: Students' perceptions and exam performance

The objective of our study was to explore the impact of COVID-19 pandemic on learning anatomy and to compare the students’ perceptions of “face-to-face” and “online” anatomy teaching, and to assess their impact on student's performance. We used a descriptive, cross-sectional, questionnaire-based study that focused on a single cohort of undergraduate medial students who attended anatomy demonstrations, at the College of Medicine and Medical Sciences, Arabian Gulf University (CMMS-AGU), both pre-pandemic (face-to-face) during 2019-2020 and the pandemic (online) during 2020-2021. Students who participated in this study responded in favor of face-to-face demonstrations for better understanding of the spatial orientation of body organs and systems, the visualization of the anatomical relations between structures, understanding the difficult anatomical structures, understanding the clinical correlations, and making them more confident about their practical exams. On the other hand, students were in favor of online demonstrations for retaining key information, confidence levels on discussing anatomy learning needs, effective utilization of demonstration time, and lower stress associated with the online learning. Regarding anatomy exam scores, statistically significant difference was found between mean scores of online and onsite exams in one of the two analyzed multiple choice questions tests. However, there was a statistically significant difference between the mean scores of objective structured practical examination of online and onsite exams in the two analyzed tests. Furthermore, the majority of the students who participated in the survey prefer a mixture of both face-to-face and online anatomy demonstrations during the pandemic and also in the post-COVID-19 era.

Natural DENV-2 NS2B/NS3 protease inhibitors from Myristica cinnamomea King

The NS2B/NS3 protease is crucial for the pathogenesis of the DENV. Therefore, the inhibition of this protease is considered to be the key strategy for the development of new antiviral drugs. In the present study, malabaricones C (3) and E (4), acylphenols from the fruits of Myristica cinnamomea King, have been respectively identified as moderate (27.33 ± 5.45 μM) and potent (7.55 ± 1.64 μM) DENV-2 NS2B/NS3 protease inhibitors, thus making this the first report on the DENV-2 NS2B/NS3 protease inhibitory activity of acylphenols. Based on the molecular docking studies, compounds 3 and 4 both have π-π interactions with Tyr161. While compound 3 has hydrogen bonding interactions with Gly151, Gly153 and Tyr161, compound 4 however, forms hydrogen bonds with Ser135, Asp129, Phe130 and Ile86 instead. The results from the present study suggests that malabaricones C (3) and E (4) could be employed as lead compounds for the development of new dengue antivirals from natural origin.

Design of Dual Band Antenna for WLAN Application

This paper presents the antenna designed with radiating structure of 3.5 for dual band applications. This antenna is designed and simulated by using CST Studio Suite software at 2.4 GHz and 5.2 GHz based on standard IEEE 802.11a (5.15 GHz-5.35 GHz) and IEEE 802.11b (2.4 GHz-2.48 GHz) frequency bands. The radiating structure 5 and 3 are designed to radiated at frequency 2.4 GHz and 5.2 GHz respectively. Then, both structures are combined to achieve dual band resonant frequencies. The techniques that have been used to achieve dual band resonant are by designing the 3.5 shaped by using planar and coplanar waveguide (CPW) structures. There are three designs of dual band antenna which are Design A, Design B and Design C. The optimum return loss for 2.4 GHz and 5.2 GHz frequency response are -16.44 dB and -18.78 dB respectively achieved by Design C. The changes on the position of radiating structure 3 will effects the frequency response, return loss and gain of the antenna.

Morphology of non-sensory epithelium during post-natal development of the rabbit vomeronasal organ

The vomeronasal organ (VNO), because of its ability to detect pheromones, has an important role in many social and sexual behaviours in mammals. It also mediates defensive behaviours through detection of protein pheromone homologues. A detailed morphological description of the post-natal development of the 'non-sensory' epithelium (NSE) of the female rabbit is recorded. Histological techniques were used to study the NSE of the VNO in post-natal development of female rabbits. The study focused on the following post-natal ages: newborn, 1 week, 2 weeks and 1 month (five animals each) beside to two adult animals. The rabbit VNO was surrounded externally by bony capsule and internally by cartilaginous capsule. NSE was pseudostratified columnar partially ciliated epithelium without goblet cells. In addition to basal cells, NSE contained ciliated and three types of non-ciliated columnar cells (dark, pale and light). At birth, dark cells may have primary cilia. By 1 month, the cytoplasm became lighter with less free ribosomes. The pale cells had electron-lucent cytoplasm, which contained a few organelles. Mitotic figures were observed in basal and columnar cells, particularly during the first 2 weeks of post-natal development. Light columnar cells were common during the first week. Numerous leucocytes and a few nerve endings were detected intra-epithelial. Scanning electron microscope revealed a gradual increase in height of microvilli of non-ciliated cells. Ciliated cells had cilia and microvilli. Cells were arranged singly, in clumps or in a dense population of cells. The rabbit VNO-NSE had a unique morphological structure.

Interspecies comparison of pharmacokinetic profile and bioavailability of (+/-)-gossypol in male Fischer-344 rats and male B6C3F mice

Gossypol is a naturally occurring yellow substance in cotton plant that has male reproductive toxicity both in humans and some experimental animal species. Interspecies oral bioavailability and pharmacokinetic profile of (+/-)-gossypol were compared in male Fischer-344 rats and B6C3F mice after a 1) single intravenous dose, 2) single oral dose, and 3) 14 consecutive, daily, oral doses; all doses were 10 and 50 mg/kg rats and mice, respectively. In both species, the intravenous plasma (+/-)-gossypol concentrations showed a triexponential pattern, indicating a 3-compartment, open-model system. The apparent half-life of elimination of (+/-)-gossypol following intravenous injection was 9.1 h and 7.7 h in rats and mice, respectively. The total plasma clearance (Cl), volume of distribution (Vd), and AUCplasma after a single intravenous injection were 1.84 and 1.23 l/h per kg, 0.20 and 1.74 l/kg, and 36.0 and 115.8 mg.h/l, in rats and mice, respectively. The bioavailability of a single, oral dose of (+/-)-gossypol was 86% and 14.3% in rats and mice, respectively. In rats the change in plasma (+/-)-gossypol concentration after a single, dose was monophasic; multiple doses showed a biphasic pattern. In mice a single, dose of (+/-)-gossypol showed a biexponential plasma concentration pattern; daily dosing was monoexponential and was eliminated twice as fast as the single dose. Also, multiple doses of (+/-)-gossypol in the mouse were eliminated 7 times faster than in the rat. These findings are consistent with previous results that daily, oral dosing of (+/-)-gossypol, but not a single dose, produces infertility in the male rat, while the mouse is insensitive to (+/-)-gossypol action. The results of this study indicate that differential sensitivity of rats and mice to the contraceptive action of (+/-)-gossypol may be related, at least in part, to its pharmacokinetic profiles in both species.

Pharmacokinetic profile of (+/-)-gossypol in male Sprague-Dawley rats following single intravenous and oral and subchronic oral administration

The pharmacokinetic profile of (+/-)-gossypol was determined in male Sprague-Dawley rats following a single intravenous or oral 10 mg/kg dose and after receiving a daily oral 10 mg/kg dose for 14 days. The intravenous plasma (+/-)-gossypol level data were fitted with a three-compartment, open-model system. The apparent half-life of elimination of (+/-)-gossypol following intravenous administration was 11.44 hr, corresponding to an elimination rate constant of 0.05 hr-1. The total plasma clearance (Cl), volume of distribution (Vd), and AUCplasma following a single intravenous administration were 0.16 liter/hr/kg, 0.05 liter/kg, and 63.09 mg.hr/liter, respectively. The bioavailability of a single oral dose of (+/-)-gossypol in rats was 60%. The change in plasma (+/-)-gossypol concentration after a single or after multiple doses showed a biphasic pattern. A single oral dose of (+/-)-gossypol, however, was eliminated five times faster than the daily administered chemical. Thus, a single oral dose of (+/-)-gossypol was eliminated at a rate constant of 0.01 hr-1, corresponding to half-life of 64.76 hr. Subchronic oral administration of (+/-)-gossypol showed an apparent half-life of 101.91 hr-1, corresponding to a rate constant of 0.007 hr-1. The results indicate that multiple oral dosing of (+/-)-gossypol resulted in its longer retention in body tissue than a single oral dose. This study suggests that pharmacokinetics of (+/-)-gossypol may play, at least in part, a role in the reproductive toxicity of subchronic but not single oral dosing.

Delayed neurotoxicity of Cyanofenphos in chickens

Delayed neurotoxic ataxia, similar to that caused by neurotoxic organophosphorous compounds, has been shown to occur in hens after oral administration of Cyanofenphos (O-ethyl-O-Cyanophenyl phenyl phosphonothionate) following either single or repeated oral doses. Axonal and myelin degeneration affecting the long tracts in spinal cord, peripheral nerves and medulla was demonstrated. The distal fibers with large diameters were particularly affected. This finding is a new contribution which has not been previously recorded. It implies that a thorough study of the structure-activity relationships of phosphonothionates regarding their delayed neurotoxic effect is warranted.