Age-stratified transmission model of COVID-19 in Ontario with human mobility during pandemic's first wave

In this work, we employ a data-fitted compartmental model to visualize the progression and behavioral response to COVID-19 that match provincial case data in Ontario, Canada from February to June of 2020. This is a "rear-view mirror" glance at how this region has responded to the 1st wave of the pandemic, when testing was sparse and NPI measures were the only remedy to stave off the pandemic. We use an SEIR-type model with age-stratified subpopulations and their corresponding contact rates and asymptomatic rates in order to incorporate heterogeneity in our population and to calibrate the time-dependent reduction of Ontario-specific contact rates to reflect intervention measures in the province throughout lockdown and various stages of social-distancing measures. Cellphone mobility data taken from Google, combining several mobility categories, allows us to investigate the effects of mobility reduction and other NPI measures on the evolution of the pandemic. Of interest here is our quantification of the effectiveness of Ontario's response to COVID-19 before and after provincial measures and our conclusion that the sharp decrease in mobility has had a pronounced effect in the first few weeks of the lockdown, while its effect is harder to infer once other NPI measures took hold.

Could high DNA stainability (HDS) be a valuable indicator of sperm nuclear integrity?

Background

The Sperm Chromatin Structure Assay (SCSA®), in addition to identifying the DNA Fragmentation Index (DFI) also identifies High DNA satiability (HDS), supposed to reflect the nuclear compaction of spermatozoa. However, data on what exactly this parameter reveals, its relevance and usefulness are contradictory. In order to shed light on this situation, spermatozoa of a cohort (N = 397) of infertile men were subjected to the SCSA®, TUNEL (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling) and CMA3 (Chromomycin A3) tests. In a smaller subcohort (N = 100), aniline blue (AB) and toluidine blue (TB) staining were performed in addition. The objective of this study was thus to answer the question of whether HDS is a relevant and reliable parameter to be taken into account?

Results

HDS does not appear to be a reliable indicator of nuclear immaturity because it shows a weak correlation with the CMA3, AB and TB stains. The low correlation of HDS with sperm DNA fragmentation (TUNEL and SCSA®) and DNA condensation (CMA3, AB and TB) tests suggests that these two parameters could be decoupled. Unlike DFI and TUNEL, HDS has not been shown to correlate with classic clinical situations of male infertility (asthenozoospermia, teratozoospermia or astheno-teratozoospermia).

Conclusion

HDS correlates poorly with most tests that focus specifically on the level of maturity of the sperm nucleus. To our knowledge, this study is the first to compare SCSA®, TUNEL, AB, TB and CMA3 assays on identical samples. It shows the potency, consistency and limitations of each test and the care that must be taken in their interpretation.

Using intron splicing trick for preferential gene expression in transduced cells: an approach for suicide gene therapy

Suicide gene therapy is one of the most innovative approaches in which a potential toxic gene is delivered to the targeted cancer cell by different target delivery methods. We constructed a transfer vector to express green fluorescent protein (GFP) in transduced cells but not in packaging cells. We placed gfp under the control of the cytomegalovirus (CMV) promoter, which is positioned between the two long-terminal repeats in reverse direction. The intron-2 sequence of the human beta globin gene with two poly-A signals and several stop codons on the antisense strand was placed on the leading strand between the CMV promoter and gfp. For lentiviral production, the HEK293T and line were co-transfected with the PMD2G, psPAX2 and pLentiGFP-Ins2 plasmids. The HEK293T and line were transduced with this virus. PCR was performed for evaluation of intron splicing in transduced cells. The GFP expression was seen in 65% of the cells transduced. The PCR amplification of the genomic DNA of transduced cells confirmed the splicing of intron 2. The strategy is significant to accomplish our goal for preserving the packaging cells from the toxic gene expression during viral assembly and the resultant reduction in viral titration. Also it serves to address several other issues in the gene therapy.

Determining the minimum inhibitory concentration of Tetraclean against Candida albicans

The purpose of the present study was to determine the minimum inhibitory concentrations of Tetraclean, chlorhexidine, hydrogen peroxide, and sodium hypochlorite against Candida albicans.Amphotericin B was used as positive control and RPMI plus 1 ml Candida suspension was used as negative control. Serial dilution method was used to determine MIC of the irrigants. Findings showed that all positive controls demonstrated complete inhibition of C. albicans at concentration of 0.78 microg mL(-1). On the other hand, all negative controls were positive for fungal growth which confirms the methodology of the study. Findings showed that the MIC of CHX was significantly lesser than other tested irrigants (p < 0.05). The MICs of other groups in an ascending order were as follows: Tetraclean, NaOCl, and H2O2. However, the difference betweenTetraclean and NaOCI was not significant (p > 0.05). It can be concluded that MIC of CHX was significantly lower than other irrigations solutions which confirms its strong antifungal activity.

The incidence of cleft lip and palate in a Kurd population: a prospective study

AIM

To assess the incidence of cleft lip and palate and factors associated with them in the hospital births of Iran's Kurdistan province in 2010.

METHODS

Researcher-completed questionnaires captured data on gender, mother's age during pregnancy, parents' occupation, father's birthplace, family background, consanguinity, systemic diseases, mother's disease during pregnancy, drugs abuse, smoking, alcohol drinking, radiography and mother's radiotherapy during pregnancy.

RESULTS

Of 26,537 newborns, 29 (19 male and 10 females) were affected by various types of cleft lip and palate. Of newborns with cleft lip and palate: 38% had other abnormalities, consanguinity was reported in about 31% of cases and 28% of mothers used prescribed drugs during pregnancy while no mothers used cigarettes or alcohol. There was no report of radiotherapy or radiography.

CONCLUSIONS

The incidence rate of oral clefts was 1.09 in the 1,000 live births.

Rip3 knockdown rescues photoreceptor cell death in blind pde6c zebrafish

Achromatopsia is a progressive autosomal recessive retinal disease characterized by early loss of cone photoreceptors and later rod photoreceptor loss. In most cases, mutations have been identified in CNGA3, CNGB3, GNAT2, PDE6C or PDE6H genes. Owing to this genetic heterogeneity, mutation-independent therapeutic schemes aimed at preventing cone cell death are very attractive treatment strategies. In pde6c(w59) mutant zebrafish, cone photoreceptors expressed high levels of receptor-interacting protein kinase 1 (RIP1) and receptor-interacting protein kinase 3 (RIP3) kinases, key regulators of necroptotic cell death. In contrast, rod photoreceptor cells were alternatively immunopositive for caspase-3 indicating activation of caspase-dependent apoptosis in these cells. Morpholino gene knockdown of rip3 in pde6c(w59) embryos rescued the dying cone photoreceptors by inhibiting the formation of reactive oxygen species and by inhibiting second-order neuron remodelling in the inner retina. In rip3 morphant larvae, visual function was restored in the cones by upregulation of the rod phosphodiesterase genes (pde6a and pde6b), compensating for the lack of cone pde6c suggesting that cones are able to adapt to their local environment. Furthermore, we demonstrated through pharmacological inhibition of RIP1 and RIP3 activity that cone cell death was also delayed. Collectively, these results demonstrate that the underlying mechanism of cone cell death in the pde6c(w59) mutant retina is through necroptosis, whereas rod photoreceptor bystander death occurs through a caspase-dependent mechanism. This suggests that targeting the RIP kinase signalling pathway could be an effective therapeutic intervention in retinal degeneration patients. As bystander cell death is an important feature of many retinal diseases, combinatorial approaches targeting different cell death pathways may evolve as an important general principle in treatment.

Dislocation of the zygomatic bone into the nasal cavity

A 25-year-old patient sustained a traumatric dislocation of the right zygomatic bone into the nasal cavity. After ten days the bone was taken out of the nose and fixed in its presumed original place. After the operation, the facial contour was desirable and orbital functions were also normal.

Substantivity of three concentrations of tetraclean in bovine root dentin

In the present study, the residual antibacterial activity, or substantivity, of three concentrations of Tetraclean (Ogna Laboratori Farmaceutici, Muggiò, Italy) was assessed in bovine root dentin in vitro. One hundred ten dentin tubes prepared from bovine incisor teeth were infected in vitro for 14 days with Enterococcus faecalis. Thereafter, the specimens were divided into five groups as follows: 100% Tetraclean, 10% Tetraclean, 1% Tetraclean, sterile dentin tubes (negative control), and infected dentin tubes (positive control). Dentin chips were collected with round burs into tryptic soy broth and, after culturing, the number of colony-forming units (CFU) was counted. The number of CFU was minimal in the first cultures in all experimental groups, and the results obtained were significantly different in the different groups at all time periods (p<0.05). At all five experimental periods, the 100% Tetraclean group showed the most effective antibacterial action (p<0.05). In each group, the number of CFU increased significantly with time (p<0.05). There was a direct relationship between the concentration of Tetraclean and its substantivity. In conclusion, under the conditions of the study presented here, the substantivity of 100% Tetraclean was significantly higher than that of lower concentrations.

Antimicrobial activity of calcium hydroxide in endodontics: a review

The purpose of endodontic therapy is to preserve the patient's natural teeth without compromising the patient's local or systemic health. Calcium hydroxide has been included in several materials and antimicrobial formulations that are used in several treatment modalities in endodontics, such as inter-appointment intracanal medicaments. The purpose of this article was to review the antimicrobial properties of calcium hydroxide in endodontics. Calcium hydroxide has a high pH (approximately 12.5-12.8) and is classified chemically as a strong base. The lethal effects of calcium hydroxide on bacterial cells are probably due to protein denaturation and damage to DNA and cytoplasmic membranes. Calcium hydroxide has a wide range of antimicrobial activity against common endodontic pathogens but is less effective against Enterococcus faecalis and Candida albicans. Calcium hydroxide is also a valuable anti-endotoxin agent. However, its effect on microbial biofilms is controversial.

The effect of ascorbic Acid on the substantivity of tetraclean in sodium hypochlorite-treated bovine dentin

OBJECTIVE

The purpose of this study was to assess the in vitro effect of ascorbic acid on the antibacterial substantivity of Tetraclean in bovine root dentin pretreated with sodium hypochlorite (NaOCl).

MATERIALS AND METHODS

Eighty dentin tubes prepared from bovine incisor teeth were infected with Enterococcus faecalis for 14 days. The specimens were divided into five groups as follows: Tetraclean; 5.25% NaOCl/Tetraclean; 5.25% NaOCl/ascorbic acid/Tetraclean; infected dentin tubes (positive control); and sterile dentin tubes (negative control). At experimental times of 0, 7, 14, 21 and 28 days, dentin chips were removed from the canals by sequential sterile low-speed round burs with increasing diameters of 025, 027, 029, 031 and 033 ISO sizes, respectively. After culturing, the number of colony-forming units (CFU) was counted.

RESULTS

In all experimental groups, the number of CFU was minimum in the first cultures and the results obtained were significantly different at any time period (p < 0.05). The Tetraclean group showed the most effective antibacterial action at all five experimental periods (p < 0.05). NaOCl/Tetraclean group showed the least antibacterial activity at all time periods. The NaOCl/ascorbic acid/Tetraclean group showed similar antibacterial substantivity to the Tetraclean group at all time periods (p> 0.05).

CONCLUSION

Ascorbic acid prevents the decrease of residual antibacterial activity of Tetraclean in dentin samples pretreated with NaOCl.

Association of pulp stones with coronary artery stenosis

BACKGROUND

Dental pulp stones are discrete calcifications in the pulp chamber which are often seen in deciduous and permanent teeth. It has been hypothesised that atherosclerosis can be associated with their development.

OBJECTIVE

To determine whether a higher prevalence of dental pulp stones is correlated with coronary artery stenosis.

CLINICAL SETTING

Sixty-one patients aged 20-55 years referred to Afshar Heart Center for invasive coronary angiography were invited to undergo panoramic dental radiography. The panoramic radiographs were independently examined for the presence of pulp stones.

RESULTS

Pulp stones were present in 82% (31/38) of patients with at least one clinically significant coronary artery stenosis and in 48% (11/23) of patients with normal coronary angiography. They were present in 13% of the teeth in the former group and in 5% of the teeth in the latter. The findings show a statistically significant association between coronary artery stenosis and presence of pulp stones (odds ratio 4.83, 95% confidence interval 1.5-15.4).

CONCLUSION

Coronary artery stenosis and dental pulp calcification are significantly associated. Dental radiography has the potential to be used as a rapid screening method for the early detection of coronary artery stenosis.

In vivo transfection study of chitosan-DNA-FAP-B nanoparticles as a new non viral vector for gene delivery to the lung

Gene therapy targeted at the respiratory epithelium holds therapeutic potential for diseases such as cystic fibrosis and lung cancer. We recently reported that Chitosan-DNA-FAP-B nanoparticles are good candidates for targeted gene delivery to fibronectin molecules (FAP-B receptors) of lung epithelial cell membrane. In this study Chitosan-DNA-FAP-B nanoparticles were nebulized to mice using air jet nebulizer. The effect of nebulization on size, zeta potential and DNA binding ability of nanoparticles were studied. The level of gene expression in the mice lungs was evaluated. Nebulization did not affect the physicochemical properties of nanoparticles. Aerosol delivery of Chitosan-DNA-FAP-B nanoparticles resulted in 16-fold increase of gene expression in the mice lungs compared with Chitosan-DNA nanoparticles. This study suggested that Chitosan-FAP-B nanoparticle can be a promising carrier for targeted gene delivery to the lung.

Properties and applications of calcium hydroxide in endodontics and dental traumatology

Calcium hydroxide has been included within several materials and antimicrobial formulations that are used in a number of treatment modalities in endodontics. These include, inter-appointment intracanal medicaments, pulp-capping agents and root canal sealers. Calcium hydroxide formulations are also used during treatment of root perforations, root fractures and root resorption and have a role in dental traumatology, for example, following tooth avulsion and luxation injuries. The purpose of this paper is to review the properties and clinical applications of calcium hydroxide in endodontics and dental traumatology including its antibacterial activity, antifungal activity, effect on bacterial biofilms, the synergism between calcium hydroxide and other agents, its effects on the properties of dentine, the diffusion of hydroxyl ions through dentine and its toxicity. Pure calcium hydroxide paste has a high pH (approximately 12.5-12.8) and is classified chemically as a strong base. Its main actions are achieved through the ionic dissociation of Ca(2+) and OH(-) ions and their effect on vital tissues, the induction of hard-tissue deposition and the antibacterial properties. The lethal effects of calcium hydroxide on bacterial cells are probably due to protein denaturation and damage to DNA and cytoplasmic membranes. It has a wide range of antimicrobial activity against common endodontic pathogens but is less effective against Enterococcus faecalis and Candida albicans. Calcium hydroxide is also an effective anti-endotoxin agent. However, its effect on microbial biofilms is controversial.

Laser application in tooth bleaching: an update review

Since the development of laser, a variety of potential applications for lasers in endodontics such as pulp diagnosis, disinfection of the root canal system, canal shaping, obturation of the root canal, apicoectomy, treatment of dentin hypersensitivity, and tooth bleaching have been proposed. The aim of this paper was to review the benefits and drawbacks of laser tooth bleaching.

The risk factors and laboratory diagnostics for post renal transplant tuberculosis: a case-control, country-wide study on definitive cases

BACKGROUND

Tuberculosis (TB) is an important cause of morbidity and mortality in renal transplant recipients and, because of its infrequency and the lack of medical awareness, it is usually misdiagnosed. This study was carried out to determine frequency and weight of multiple risk factors for post kidney transplantation TB.

METHODS

A total of 44 cases (0.3%), out of 12,820 patients from 12 major kidney transplantation centers in Iran from 1984 to 2003, were compared with 184 healthy transplant subjects who were transplanted by the same surgical team.

RESULTS

The mean age of cases and controls was 37.7 (13-63) and 35.6 (8-67) years (P=0.3), respectively. The mean duration of pre-transplantation hemodialysis was 30.3 (3-168) months in cases and 18.2 (1-180) months in controls (P=0.03). A positive past history of TB was detected in 2 cases and 1 control (P=0.3). The mean doses of initial and maintenance immunosuppressive drugs in cases and controls were not significantly different. A total of 25 cases (56.8%) and 60 controls (32.6%) had rejection before diagnosis of TB (P=0.004; OR=2.7, CI(95%): 1.3-5.6).

CONCLUSIONS

To our knowledge, this is the first study that demonstrated an increase in the risk of post-transplant TB by increasing the duration of pre-transplant hemodialysis and the number of post-transplant rejection episodes as 2 immunocompromised states. Further study is needed to clarify our new findings, specifically in relation to different immunosuppressive regimens.

In vitro dissolution of plasma-sprayed hydroxyapatite coatings with different characteristics: experimental study and modeling

The dissolution of plasma-sprayed hydroxyapatite (PHA) coatings with different characteristics, produced by various spraying conditions, in a Tris-buffered solution at pH 7.4 was experimentally studied through the measurement of the release of calcium ions. The phase composition of the coatings at surface and interface, and the porosity were evaluated. The analytical modeling revealed that the calcium dissolution process was composed of two stages. The first stage was found to be both surface and diffusion controlled. The second stage was an exactly diffusion-controlled dissolution. In the first stage, the rate of dissolution and the solubility of the coatings with minimum contents of impurity phases were mainly influenced by the contents of recrystallized HA (RHA) and amorphous calcium phosphate (ACP). It is suggested that the optimized values of the ACP and the RHA at the coating surface can tend to encourage the early fixation properties of the PHA coatings.

Preliminary Report of a Nationwide Case-Control Study for Identifying Risk Factors of Tuberculosis Following Renal Transplantation

BACKGROUND

Tuberculosis (TB) is an important infection encountered posttransplantation, especially among patients in developing countries, where there are high incidences of morbidity and mortality.

MATERIALS AND METHODS

One hundred and twenty subjects (1%) from 15 major kidney transplantation centers in Iran from 1984 to 2003 were compared with 440 controls who were matched for operative time, treatment center, and surgical team.

RESULTS

Mean ages of research subjects and controls were 38.6 and 36.6 years (P = .04), respectively. The mean duration of pretransplantation hemodialysis was 29 months (range, 2 to 192 months) in research subjects and 20 months (range, 1 to 180 months) in controls (P = .003). Positive past history of tuberculosis was detected in 4 (3.3%) research subjects and in 7 (1.5%) controls (P = .2). Fifty-two research subjects (43.3%) and 241 controls (54.8%) had pretransplantation purified protein derivative of tuberculin less than 5 mm (P = .02). Mean dosages of initial and maintenance immunosuppressive drugs in research subjects and in controls were not significantly different. Sixty research subjects (50%) and 152 controls (34.5%) had rejection prior to diagnosis of TB (P = .03).

CONCLUSION

To our knowledge, this is the first study that demonstrates an increased risk of posttransplant TB by prolonged duration of pretransplant hemodialysis and number of posttransplant rejection episodes. Further study is needed to clarify these findings specifically with respect to various immunosuppressive regimens.