Objective Proteoglycans (PGs) are multifunctional biomacromolecules of the extracellular matrix of collagen-based tissues. In teeth, besides a pivotal regulatory role on dentin biomineralization, PGs provide mechanical support to the mineralized tissue and compressive strength to the biosystem. This study assessed enzymatic protocols for selective PGs removal from demineralized dentin to determine the roles of these biomacromolecules in the bulk mechanical properties and biostability of type I collagen. Methods Selective removal of glycosaminoglycans chains (GAGs) and PGs from demineralized dentin was carried out by enzymatic digestion protocols using chondroitinase ABC (c-ABC) and trypsin (Try). A comprehensive study design included assessment of dentin matrix mass loss, biodegradability of the PGs/GAGs-depleted dentin matrix, ultimate tensile strength (UTS) and energy to fracture tests. Quantitative data was statistically analyzed by two-way and one-way ANOVA followed by the appropriate post hoc tests (α = 0.05). Results Transmission electron microscopy images show effective GAGs removal by c-ABC and Try and both enzymatic methods released statistically similar amounts of GAGs from the demineralized dentin. Try digestion resulted in about 25% dentin matrix mass loss and increased susceptibility to collagenolytic digestion when compared to c-ABC (p = 0.0224) and control (p = 0.0901). Moreover, PGs digestion by Try decreased the tensile strengths of dentin. Statistically lower energy to fracture was observed in c-ABC-treated dentin matrix. Conclusions GAGs plays a pivotal role on tissue mechanics and anisotropy, while the core protein of PGs have a protective role on matrix biostability.

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Introduction: Second hand smoke (SHS) is reported to cause 890,000 deaths annually worldwide. It is also a known cause of serious complications in pregnancy. The current study intends to fill in some of the knowledge gap for further research & effective public health interventions. Objective: To estimate the magnitude of exposure to second hand smoke and assess awareness about it among pregnant women visiting four selected tertiary care hospitals of Peshawar. Materials & Methods: A descriptive cross-sectional study was conducted at four tertiary hospitals of Peshawar from 1st January to 1st March 2018. Non-probability serial sample of 410 pregnant women was taken. A structured questionnaire was used to collect data. Data were analysed for descriptive statistics using SPSS version 22. Results: A total of 410 pregnant women were included. The mean age was 21 + 4 years; 149 (36.3%) of the total subjects were exposed to SHS, highest frequency (49%) being in age group 26-35 years. Exposure to SHS was highest (39%) among illiterate ladies; 92% of the subjects were exposed to SHS at home, the main source being their husbands (46%); 40.7% of the subjects were aware of the adverse effects of SHS on fetus, younger (p=0.01) & more educated women (p=0.001) being more likely to be aware. Conclusions: Exposure of pregnant women to second hand smoke is a public health concern in Peshawar, being more likely among younger, less educated, unaware women, and housewives.