Evidence of human hemoglobin interaction and chorionic gonadotropin hormone: Prospects for the use of hemoglobin as ligand in affinity chromatography for the purification of the hormone

The purification of biomolecules is a necessary step in many biochemical researches. In this regard, developments of convenient, specific and low cost methods of purification are of particular interest. Given the human hemoglobin (Hb) affinity toward some charged carbohydrates, interaction of this molecule with human chorionic gonadotropin (hCG) which is a glycoprotein hormone containing sialic acid, was examined. In the current study, we gathered evidence of free hCG and free Hb interaction using spectroscopic and radiometric techniques. Then, based on the affinity of hemoglobin (Hb) toward charged carbohydrates on human chorionic gonadotropin (hCG), a known sialic acid containing glycoprotein hormone, Hb-sepharose as well as native and denatured globin columns for isolation of the hormone were prepared. Sepharose-6B was activated by cyanogens bromide. Native Hb, normal globin and denatured globin were bound to cyanogen bromide–activated sepharose. Then, uptake of hCG by these gels were compared. Among the columns only native hemoglobin-sepharose column was able to catch a limited number of serum proteins such as hCG. Using the above column hCG hormone was purified with fold purification of 34 and efficiency of 80%. The chromatographic behavior of growth hormone (GH) and hCG in binding to the DEAE-Cellulose column were identical but GH showed no binding to Hb-sepharose column, indicating that the retention mechanism of hCG to Hb-sepharose column is not a simple ion exchange mode. Since globin had no property to attach to hCG but native Hb-sepharose was able to catch hCG, the BPG cavity of Hb is suggested as the possible binding site for hCG to Hb

Destructive effects of citric acid, lactic acid and acetic acid on primary enamel microhardness

Objective: This study aimed to assess the destructive effects of citric acid, lactic acid and acetic acid produced from the fermentation of foods on primary teeth enamel.Methods: This in vitro, experimental study was conducted on 24 sound primary teeth. The teeth  were polished with a fine abrasive paper under running water. Tooth pieces measuring 3×4×3mm were cut out of the teeth and stored in 100% humidity until the experiment. The specimens were divided into 3 groups (n=8) and immersed in acetic acid, citric acid and lactic acid, respectively. The enamel microhardness of specimens was measured by Vickers microhardness tester at baseline and 5 and 30min after immersion in the freshly prepared acid solutions.Results: Repeated measures ANOVA showed that the effect of immersion time on microhardness was significant (p<0.001). Pairwise comparison among 0, 5 and 30 minutes time points using Bonferroni adjustment showed significant differences in microhardness at different time points (p<0.001). Evaluation of the effect of type of acid on microhardness revealed that the microhardness was not significantly different in the three groups of acids (p=0.915). Among the three understudy acids, only the reduction in microhardness from time 0 to 30 minutes was significantly different between lactic acid and acetic acid (p=0.042).Conclusion: Citric acid, lactic acid and acetic acid were all capable of demineralization and reduction of enamel microhardness. A significant difference existed in the demineralization potential of acids (the highest for lactic acid). However, this effect was more significant early after exposure

The Effect of Adding Fentanyl to Epinephrine-Containing Lidocaine on the Anesthesia of Maxillary Teeth with Irreversible Pulpitis: A Randomized Clinical Trial

Introduction: Deep and long-lasting anesthesia is essential throughout endodontic treatment. This study was conducted to compare the effect of adding fentanyl to epinephrine-containing lidocaine on depth and duration of local anesthesia in painful maxillary molars with irreversible pulpitis (IRP). Methods and Materials: This randomized double-blind, clinical trial with parallel design was conducted on 61 healthy volunteers; the control group received a mixture of normal saline and 2% lidocaine with 1:80000 epinephrine and the experimental group received a mixture of fentanyl and 2% lidocaine with 1:80000 epinephrine. The depth and duration of pulpal anesthesia were evaluated by means of electric pulp testing in 5-min intervals during a period of 60 min. Pain intensity was recorded five times: before injection, after injection, during access cavity preparation, initial file placement and pulpectomy using visual analog scale (VAS). All data were analyzed and compared using the chi-square and Mann-Whitney tests. Results: Except for one patient in the control group, all others had deep and long-lasting anesthesia. The difference between pain intensity of the control and experimental groups was not statistically significant (P>0.05). Conclusion: Addition of fentanyl to conventional local anesthetic solution did not increase the effectiveness of infiltration in patients diagnosed with IRP

Correlation Between Pulp Sensibility Tests and Histologic Diagnosis

Introduction: Accurate diagnosis of dental pulp conditions plays a key role in selection of an appropriate treatment including conservative vital pulp therapy (treatable pulp) or root canal treatment (untreatable pulp). The purpose of this study was to assess the accuracy of sensibility tests and the correlation of pulp response to sensibility tests with histologic pulp condition. Material and Methods: Assessment of clinical signs and symptoms and sensibility test include thermal and electrical pulp tests were all performed for 65 permanent teeth. The normal pulp and reversible pulpitis were considered as treatable conditions while the irreversible pulpitis and necrosis ones were considered as untreatable condition. The teeth were then extracted and sectioned for histological analysis of dental pulp. Comparisons between histological treatable and untreatable pulp condition were performed with chi square analysis for sensibility test responses. Result: A significant difference was detected in the normal and a sharp lingered response to heat and cold tests with a marginally significant difference for no responses to cold test between two histological treatable and untreatable groups. There was significant difference in the negative response to electric pulp test (EPT) between histological groups. The kappa agreement between clinical and histological diagnosis of pulp condition was about 0.843(p<0.001).  The accuracy of cold and heat tests and EPT to detect treatable pulp or untreatable pulp states were 78% and 74% and 62% respectively. The sensibility tests diagnosed untreatable pulpitis with a higher probability (NPV=63%-67% -54%, PPV=83%-91% -95% for heat, cold and EPT respectively). Conclusion: Sensibility test results had a higher likelihood to diagnose pulpal disease or untreatable pulp conditions. The result demonstrated a good agreement between clinical and histological pulp diagnoses