The duration of spinal anaesthesia in elective caesarean section in Trendelenburg and reverse Trendelenburg positions: a randomized clinical trial

Objective

One of the common methods of anaesthesia for caesarean sections (CSs) involves the use of spinal anaesthesia in mothers. Various positions are utilized in this method. This study aims to compare the evaluation of two positions, Trendelenburg and reverse Trendelenburg, in candidates for CS to assess the duration of anaesthesia and changes in vital signs in women.

Methods

This study was a randomized clinical trial in which 60 pregnant mothers who met the inclusion criteria entered the study. These mothers were randomly allocated into two equal groups using block randomization. One group of patients received spinal anaesthesia in the Trendelenburg position, while the other group received it in the Reverse Trendelenburg position. Vital signs (systolic and diastolic blood pressure, heart rate, Apgar score, and SPO2) of participants from both groups were evaluated for 1 h after the induction of anaesthesia. Additionally, sensory level and duration of anaesthesia were measured. Finally, the data from both groups were subjected to statistical analysis using SPSS version 26 software.

Results

The mean (SD) age of participating mothers in the Reverse Trendelenburg and Trendelenburg groups was 28.93 (5.82) and 30.97 (4.94), respectively. The two study groups did not significantly differ in baseline characteristics such as age, BMI, which could potentially impact vital sign outcomes or anaesthesia duration, and education (P>0.05). The mean (SD) duration of anaesthesia in the Trendelenburg position was significantly higher than in the Reverse Trendelenburg position [221.57(min) vs. 159.00(min)] (P<0.0001). There was no significant difference between the two positions, Trendelenburg and Reverse Trendelenburg, in terms of sensory level and its extent (P=0.08). The two study groups did not significantly differ in hemodynamic changes measured 13 times, including heart rate, systolic and diastolic blood pressure, and Apgar score (P>0.05).

Conclusion

In spinal anaesthesia with the Trendelenburg position compared to the Reverse Trendelenburg position, there is a longer duration of anaesthesia. This is while the two positions did not differ in terms of hemodynamic changes and sensory level.

The implications of exosomes in psoriasis: disease: emerging as new diagnostic markers and therapeutic targets

As the largest human organ, the skin is continuously exposed to various external and internal triggers that affect body homeostasis. Psoriasis is a persistent inflammatory skin condition that has a major bearing on patients' physiological functioning as well as their mental well-being. It is an autoimmune disorder and has been the focus of extensive research efforts in recent years. Cells secrete exosomes into the environment surrounding them, which comprises a lipid bilayer. The movement of cellular components like microRNAs, mRNAs, DNA, lipids, metabolites, and cell-surface proteins is mediated by exosomes. Exosomes are crucial for inducing communication between cells. There has been extensive study of exosomes, both preclinical and clinical, looking at their potential role in autoimmune diseases. Besides the role that they play in the body's basic processes, exosomes are also considered an increasingly essential part as diagnostic and therapeutic agents. In the following article, we conduct a literature review of current studies related to molecular and structural aspects of exosomes. We emphasis on the function of exosomes in pathogenesis, as well as the possibility of their usage in medicinal applications and as biomarkers.

Screening the critical protein subnetwork to delineate potential mechanisms and protective agents associated with arsenic-induced cutaneous squamous cell carcinoma: A toxicogenomic study

Recent studies show that complex mechanisms are involved in arsenic-induced malignant transformation of cells. This study aimed to decipher molecular mechanisms associated with arsenic-induced cutaneous squamous cell carcinoma (cSCC) and suggest potential protective factors. RNA-seq-based differentially expressed genes between arsenic-exposed human keratinocytes (HaCaT) and controls were used to construct a protein-protein interaction (PPI) network and discover critical subnetwork-based mechanisms. Protective compounds against arsenic toxicity were determined and their target interactions in the core sub-network were identified by the comparative toxicogenomic database (CTD). The binding affinity between the effective factor and target was calculated by molecular docking. A total of 15 key proteins were screened out as critical arsenic-responsive subnetwork (FN1, IL-1A, CCN2, PECAM1, FGF5, EDN1, FGF1, PXDN, DNAJB9, XBP1, ERN1, PDIA4, DNAJB11, FOS, PDIA6) and 7 effective protective agents were identified (folic acid, quercetin, zinc, acetylcysteine, methionine, catechin, selenium). The GeneMANIA predicted detailed interactions of the subnetwork and revealed terms related to unfolded protein response as the main processes. FN1, IL1A and CCN2, as top significant genes, had good docking affinity with folic acid and quercetin, as selected key compounds. Integration of gene expression and protein-protein interaction related to arsenic exposure in cSCC explored the potential mechanisms and protective agents.

Unveiling diagnostic and therapeutic strategies for cervical cancer: biomarker discovery through proteomics approaches and exploring the role of cervical cancer stem cells

Cervical cancer (CC) is a major global health problem and leading cause of cancer deaths among women worldwide. Early detection through screening programs has reduced mortality; however, screening compliance remains low. Identifying non-invasive biomarkers through proteomics for diagnosis and monitoring response to treatment could improve patient outcomes. Here we review recent proteomics studies which have uncovered biomarkers and potential drug targets for CC. Additionally, we explore into the role of cervical cancer stem cells and their potential implications in driving CC progression and therapy resistance. Although challenges remain, proteomics has the potential to revolutionize the field of cervical cancer research and improve patient outcomes.

Evaluation of the Cellular Resistance Process in Treated Cells Via Extracorporeal Photopheresis

Introduction: Extracorporeal photopheresis (ECP) is a therapeutic method applied against some diseases such as cancers. Using 8-methoxypsoralen (8-MOP) and UVA radiation in ECP is associated with achievement in the treatment of patients with leukemic cutaneous T-cell lymphoma (CTCL). Evaluation of cellular resistance versus ECP is the aim of this study. Methods: Data were downloaded from the Gene Expression Omnibus (GEO) database and were analyzed via the GEO2R program. The significant DEGs were assessed via protein-protein interaction (PPI) network analysis by using the STRING database and Cytoscape software. The critical genes were evaluated via gene ontology by using the ClueGO application of Cytoscape software. The identified biological processes were determined and analyzed. Results: Fifty-seven significant DEGs were determined. The main connected component of the PPI network including 32 queried significant DEGs plus 50 first neighbors was constructed. Nineteen histones as critical nodes were assessed via gene ontology, and "nucleosome organization" was pointed out as the crucial biological process. Finally, 15 histones from H2A, H2B, and H3 histone families were identified as the key genes that are involved in the resistance property of the treated cells. Conclusion: In conclusion, 15 members of H2A, H2B, and H3 families (especially H2A family) were considered as the origin of resistance versus ECP treatment. It is concluded that sensitivity to ECP treatment depends on gross molecular events which are involved in the functions of histones.

Comparison of the effect of vaginal misoprostol and evening primrose oil capsule with misoprostol alone on the consequences of abortion in women with intrauterine fetal death: a randomized clinical trial

BACKGROUND

Misoprostol is the choice drug for inducing an abortion with intrauterine fetal death, but it has several side effects that increase with accumulating the dose received. Induction abortion with cheap and non-invasive methods with minimal complications is essential. This study aimed to compare the effect vaginal misoprostol plus vaginal evening primrose oil capsule with vaginal misoprostol alone on the consequences of abortion in pregnant women with intrauterine fetal death at 12-20 weeks of pregnancy.

METHODS

This study is a randomized, triple-blind clinical trial with two parallel groups at a ratio of 1:1. We randomized 82 women with indications of termination of pregnancy due to intrauterine fetal death into two groups. The experimental group (n = 42) received 200 mcg of misoprostol tablet with 1000 mg evening primrose oil capsule intravaginal. The control group (n = 40) received 200 mcg of misoprostol tablet with 1000 mg evening primrose oil placebo capsule intravaginal. Both groups received the drugs every 4 h for up to five doses. The primary outcome was the mean induction-to-fetal expulsion interval. Secondary outcomes were the mean dose of misoprostol, the highest pain intensity in the induction-to-fetal expulsion interval, the frequency of participants requiring blood transfusion, curettage, and the frequency of side effects of misoprostol or evening primrose oil. Pain intensity was measured through the Visual Analog Scale.

RESULTS

The mean age of the experimental group was 32.30 ± 6.19 years, and the control group was 30.27 ± 7.68 years. The mean gestational age of the experimental group was 15.29 ± 2.26 weeks, and the control group was 15.10 ± 1.89 weeks. The mean induction-to-fetal expulsion interval in the experimental group (3.12 ± 2.17 h) was significantly lower than that in the control group (8.40 ± 4.1 h) (p < 0.001). The mean dose of misoprostol received in the experimental group (271.42 ± 115.39 mcg) was significantly lower than that in the control group (520 ± 201.53 mcg) (p < 0.001). Also, the mean pain intensity in the experimental group (5.02 ± 0.60) was significantly lower than that in the control group (8.65 ± 1.001) (p < 0.001). The two groups were not significantly different in the frequency of blood transfusion requirements, analgesia and drug side effects. The need for curettage in the experimental group (4.8%) was significantly lower than that in the control group (47.5%) (p < 0.001).

CONCLUSIONS

Vaginal administration of evening primrose oil with misoprostol reduced duration of time of fetal expulsion, pain intensity, mean dose of misoprostol received, and the need for curettage in participants. Therefore, we suggest this method for induced abortion in women with intrauterine fetal death.

TRIAL REGISTRATION

IRCT20181207041873N3. Dated 16/2/2021 prospectively registered https://en.irct.ir/user/trial/53681/view .

Cavernous sinus thrombosis in ulcerative colitis recurrent after pregnancy: A case report

Inflammatory bowel disease and pregnancy are risk factors for increased hyper coagulopathy state. A 35-year-old woman with ulcerative colitis was presented in this study. She had the recurrence of the disease during pregnancy. She suffered cavernous sinus thrombosis simultaneously.

Clinicopathological and prognostic value of lncRNA TPT1-AS1 in cancer: a systematic review study and meta-analysis

INTRODUCTION

Aberrant expression of lncRNAs in cancer cells can impact their key phenotypes. We aimed to summarize available evidence on clinicopathological and prognostic value of lncRNA TPT1-AS1 in cancer.

METHODS

A systematic search was performed on Medline and Embase databases using relevant key terms covering lncRNA TPT1-AS1, cancer, and clinical outcomes. The effect size estimates and their 95 % confidence interval (CI) were pooled using random-effects models. Meta- analyses were conducted using STATA 16.0 software.

RESULTS

Seventeen articles met our eligibility criteria. Tumor tissue compared to normal tissue showed increased level of lncRNA TPT1-AS1 expression (pooled standardized mean difference (95 % CI): 0.65 (0.52-0.79)). Overexpression of this lncRNA was a significant predictor for poor prognosis (Pooled log-rank test P-value < 0.001); in patients with high-level of lncRNA TPT1-AS1, the risk of death at five years was 1.40 times greater than their counterparts. The pooled Odds ratios for association lncRNA TPT1-AS1 with tumor stage, tumor size, and lymph node metastasis were 1.94 (95 % CI: 0.90-4.19, 8 studies, I² = 79.6 %), 2.33 (95 % CI: 1.31-4.14, 5 studies, I² = 40.0 %), and 1.89 (95 % CI: 1.08-3.36, 5 studies, I² = 61.7 %), respectively. Regarding the identified potential mechanisms, lncRNA TPT1-AS1 plays a role in cancer growth mainly by sponging miRNAs and regulating their downstream targets or controlling the expression of key cell cycle regulators.

CONCLUSION

In cancer patients, elevated expression of lncRNA TPT1-AS1 might be associated with a shorter Overall Survival, advanced stages, larger tumor size, and lymph node metastasis.

The Effect of Using Dexamethasone Tablets Vaginally for Improving Cervical Bishop Score in Nulliparous Pregnant Women: A Randomized Clinical Trial

Background

Cervix ripening and labor induction are common interventions in obstetrics. For optimal maternal health, labor may be induced under certain situations to improve fetal survival outcomes. Labor induction of an unripe cervix can lead to complications; therefore, several approaches can facilitate the ripening process.

Methods

This randomized clinical trial was a triple-blind study that involved 84 pregnant nulliparous women enrolled between October 2019 and June 2021 in the labor ward of Kamali Hospital, Karaj, Iran. The pregnant women in the study underwent labor induction and were randomized into 2 groups: 1 group received vaginal dexamethasone and the other group was given a placebo.

Results

There was no significant difference between the groups regarding maternal age, demographic characteristics, and initial Bishop score. The median second Bishop score (6 hours after intervention) was 3.5 in dexamethasone recipients and 3 in placebo recipients (P = 0.48). The median labor latent phase duration was 4 hours in dexamethasone recipients and 5 hours in placebo recipients (P = 0.57).

Conclusions

This randomized clinical trial demonstrated that administering dexamethasone tablets vaginally did not significantly improve cervical Bishop scores. (Curr Ther Res Clin Exp. 2023; 84:XXX-XXX). ClinicalTrials.gov identifier: NCT05070468.

The effect of magnesium sulfate on maternal serum electrolytes and parathyroid hormone in pre-eclampsia

OBJECTIVE

To evaluate possible interactions of magnesium sulfate-the drug of choice in the management of pre-eclampsia/eclampsia-in response to a few case reports that revealed maternal electrolyte disturbances, especially symptomatic changes, following magnesium sulfate administration in pre-eclampsia.

METHODS

Prospectively, women with pre-eclampsia were given 4 g of intravenous magnesium sulfate followed by a 2 g/h infusion up to 24 h after delivery. Sequential blood samples were drawn from each patient and used to measure the serum levels of sodium, potassium, calcium, phosphorus, magnesium, and parathyroid hormone.

RESULTS

A total of 30 pregnant women with pre-eclampsia were evaluated. They were aged between 20 and 41 years with median gestational age of 37.6 (interquartile range 35.4-38.9) weeks. Only five patients reached the therapeutic window of magnesium in at least one of our measuring intervals during magnesium sulfate infusion. Plasma magnesium concentrations increased significantly during magnesium sulfate administration and dropped during the next 12 and 24 h after infusion discontinuation (P < 0.05). Fifteen of 30 (50%) patients developed asymptomatic hypocalcemia, mainly at hour 24 of infusion. Negative moderate correlations were detected between the calcium and magnesium concentrations at 12 and 24 hours of infusion (ρ = -0.390, P = 0.044 and ρ = 0.315, P = 0.096, respectively). None of the patients with hypocalcemia reached the therapeutic level of magnesium or experienced parallel hyperphosphatemia. Eleven of 30 (36.6%) patients developed hyperphosphatemia mainly at 2 and 12 h of magnesium sulfate infusion.

CONCLUSIONS

Our study implies that magnesium sulfate could cause hypermagnesemia-induced hypocalcemia in women with pre-eclampsia, independent from parathyroid hormone. The negative correlations between calcium and magnesium concentrations could be indicative of dose-dependent associations between serum magnesium level and degree of hypocalcemia in our study.

Molecular pathways involved in COVID-19 and potential pathway-based therapeutic targets

Deciphering the molecular downstream consequences of severe acute respiratory syndrome coronavirus (SARS-CoV)- 2 infection is important for a greater understanding of the disease and treatment planning. Furthermore, greater understanding of the underlying mechanisms of diagnostic and therapeutic strategies can help in the development of vaccines and drugs against COVID-19. At present, the molecular mechanisms of SARS-CoV-2 in the host cells are not sufficiently comprehended. Some of the mechanisms are proposed considering the existing similarities between SARS-CoV-2 and the other members of the β-CoVs, and others are explained based on studies advanced in the structure and function of SARS-CoV-2. In this review, we endeavored to map the possible mechanisms of the host response following SARS-CoV-2 infection and surveyed current research conducted by in vitro, in vivo and human observations, as well as existing suggestions. We addressed the specific signaling events that can cause cytokine storm and demonstrated three forms of cell death signaling following virus infection, including apoptosis, pyroptosis, and necroptosis. Given the elicited signaling pathways, we introduced possible pathway-based therapeutic targets; ADAM17 was especially highlighted as one of the most important elements of several signaling pathways involved in the immunopathogenesis of COVID-19. We also provided the possible drug candidates against these targets. Moreover, the cytokine-cytokine receptor interaction pathway was found as one of the important cross-talk pathways through a pathway-pathway interaction analysis for SARS-CoV-2 infection.

Coronavirus disease 2019 and stroke in Iran: a case series and effects on stroke admissions

OBJECTIVE

The coronavirus disease 2019 pandemic has affected healthcare systems around the globe and massively impacted patients with various non-infectious, life-threatening conditions. Stroke is a major neurological disease contributing to death and disability worldwide, and is still an ongoing issue during the pandemic. Here we investigate the impact of the coronavirus disease 2019 outbreak on stroke manifestations, treatment courses, the outcome of stroke patients, and the hospitalization rate in a referral center for stroke management in Tehran, Iran.

METHODS

We extracted data regarding 31 stroke patients (10 patients with laboratory-confirmed coronavirus disease 2019) and compared the demographic and pathological characteristics of the patients with or without coronavirus disease 2019 infection. The association of demographic/pathological characteristics of stroke patients during the coronavirus disease 2019 pandemic and a corresponding period during the previous year (49 patients) and an earlier period during the same year as the pandemic (50 patients) was also evaluated.

RESULTS

The absolute number of admissions decreased about 40% during the coronavirus disease 2019 pandemic. Except for the stroke severity (P = 0.002), there were no significant changes in the demographic and pathological characteristics of the stroke patients during the three studied periods. A significantly higher mean of age (75.60 ± 9.54 versus 60.86 ± 18.45; P = 0.007), a significant difference in the type of stroke (P = 0.046), and significantly higher stroke severity (P = 0.024) were observed in stroke patients with coronavirus disease 2019 compared with those of stroke patients without coronavirus disease 2019. Treatment approaches, duration of hospitalization, and mortality rates did not differ significantly.

CONCLUSIONS

This report shows that the pandemic caused the number of acute stroke admissions to plummet compared to other periods. Although the pandemic did not affect the treatment plans and care of the patients, stroke cases with coronavirus disease 2019 had higher age, more large vessel ischemic stroke, and more severe stroke. Further studies are urgently needed to realize the probable interaction of the coronavirus disease 2019 pandemic and the neurologic disease.

Ruled out of preeclampsia-like syndrome due to COVID-19: A case study

Coronavirus disease (COVID-19) is an infectious disease. In this study, we report a 28-year-old pregnant woman who had a postpartum seizure with a background of HELLP syndrome and a proven COVID-19 infection. Her child survived, and at 12-week postpartum, all maternal COVID-19-related symptoms vanished, and she was cured.

A pregnant woman with a history of SLE with PPROM and severe thrombocytopenia: A case study

This study discusses the management of a pregnant woman with PPROM and a history of lupus. She was found to be severely thrombocytopenic which was unresponsive to prednisolone. During cesarean section, placental abruption was found and postpartum hemorrhage ensued.

Systematic Analysis of Protein-Protein and Gene-Environment Interactions to Decipher the Cognitive Mechanisms of Autism Spectrum Disorder

Autism spectrum disorder (ASD), a heterogeneous neurodevelopmental disorder resulting from both genetic and environmental risk factors, is manifested by deficits in cognitive function. Elucidating the cognitive disorder-relevant biological mechanisms may open up promising therapeutic approaches. In this work, we mined ASD cognitive phenotype proteins to construct and analyze protein-protein and gene-environment interaction networks. Incorporating the protein-protein interaction (PPI), human cognition proteins, and connections of autism-cognition proteins enabled us to generate an autism-cognition network (ACN). With the topological analysis of ACN, important proteins, highly clustered modules, and 3-node motifs were identified. Moreover, the impact of environmental exposures in cognitive impairment was investigated through chemicals that target the cognition-related proteins. Functional enrichment analysis of the ACN-associated modules and chemical targets revealed biological processes involved in the cognitive deficits of ASD. Among the 17 identified hub-bottlenecks in the ACN, PSD-95 was recognized as an important protein through analyzing the module and motif interactions. PSD-95 and its interacting partners constructed a cognitive-specific module. This hub-bottleneck interacted with the 89 cognition-related 3-node motifs. The identification of gene-environment interactions indicated that most of the cognitive-related proteins interact with bisphenol A (BPA) and valproic acid (VPA). Moreover, we detected significant expression changes of 56 cognitive-specific genes using four ASD microarray datasets in the GEO database, including GSE28521, GSE26415, GSE18123 and GSE29691. Our outcomes suggest future endeavors for dissecting the PSD-95 function in ASD and evaluating the various environmental conditions to discover possible mechanisms of the different levels of cognitive impairment.

A systematic review of microRNA expression studies with exposure to bisphenol A

Bisphenol A (BPA), as a common industrial component, is generally consumed in the synthesis of polymeric materials. To gain a deeper understanding of the detrimental effects of BPA, BPA-induced microRNA (miRNA) alterations were investigated. A systematic search was performed in the PubMed, SCOPUS and Web of Science databases to evoke relevant published data up to August 10, 2019. We identified altered miRNAs that have been repeated in at least three studies. Moreover, miRNA homology analysis between human and nonhuman species was performed to determine the toxicity signatures of BPA in human exposure. In addition, to reflect the effects of environmental exposure levels of BPA, the study designs were categorized into two groups, including low and high doses according to the previous definitions. In total, 28 studies encountered our criteria and 17 miRNAs were identified that were differentially expressed in at least three independent studies. Upregulating miR-146a and downregulating miR-192, miR-134, miR-27b and miR-324 were found in three studies. MiR-122 and miR-29a were upregulated in four studies after BPA exposure, and miR-21 was upregulated in six studies. The results indicate that BPA at low-level exposures can also alter miRNA expression in response to toxicity. Finally, the miRNA-related pathways showed that BPA seriously can affect human health through various cell signaling pathways, which were predictable and consistent with existing studies. Overall, our findings suggest that further studies should be conducted to examine the role of miRNA level changes in human BPA exposure.

Investigating the human protein-host protein interactome of SARS-CoV-2 infection in the small intestine

AIM

The present study aimed to identify human protein-host protein interactions of SARS-CoV-2 infection in the small intestine to discern the potential mechanisms and gain insights into the associated biomarkers and treatment strategies.

BACKGROUND

Deciphering the tissue and organ interactions of the SARS-CoV-2 infection can be important to discern the potential underlying mechanisms. In the present study, we investigated the human protein-host protein interactions in the small intestine.

METHODS

Public databases and published works were used to collect data related to small intestine tissue and SARS-CoV-2 infection. We constructed a human protein-protein interaction (PPI) network and showed interactions of host proteins in the small intestine. Associated modules, biological processes, functional pathways, regulatory transcription factors, disease ontology categories, and possible drug candidates for therapeutic targets were identified.

RESULTS

Thirteen primary protein neighbors were found for the SARS-CoV-2 receptor ACE2. ACE2 and its four partners were observed in a highly clustered module; moreover, 8 host proteins belonged to this module. The protein digestion and absorption as a significant pathway was highlighted with enriched genes of ACE2, MEP1A, MEP1B, DPP4, and XPNPEP2. The HNF4A, HNF1A, and HNF1B transcription factors were found to be regulating the expression of ACE2. A significant association with 12 diseases was deciphered and 116 drug-target interactions were identified.

CONCLUSION

The protein-host protein interactome revealed the important elements and interactions for SARS-CoV-2 infection in the small intestine, which can be useful in clarifying the mechanisms of gastrointestinal symptoms and inflammation. The results suggest that antiviral targeting of these interactions may improve the condition of COVID-19 patients.

Abstract P6-05-02: Identification of microRNAs differentially expressed in brain metastasis secondary to breast cancer

Background: Despite sequential improvements in the adjuvant treatment of breast cancer (BC), recurrence and metastasis remains a major clinical problem and in particular, brain metastasis (BCBM). A number of microRNAs (miRNAs) have been linked to the metastatic process in BC, but to date there is limited work on the microRNAs involved in BCBM. The current study aim to identify differentially expressed miRNAs within primary breast cancer who did not recur (BCNR) versus primary BC cases which did recur (BCR) and their matched BCBM cases.

Methods: Formalin-fixed paraffin-embedded (FFPE) material was collected of 12 primary BCNRs from the Liverpool tissue bank and of 40 paired primary BCR samples and their matched BCBM from the Walton Research Tissue Bank and RCSI National Breast Cancer Bioresource. miRNA was extracted (Qiagen miRNeasy FFPE kit) and profiled using the NanoString™ nCounter™ miRNA Expression Assay (Human v3 miRNA). The differentially expressed miRNAs between BCNR versus BCR and BCR versus their matched BCBM were identified by significance of microarray analysis (SAM) on the MeV4.9 software. Pathway analysis was performed using the DIANA-mirPath v3.0 software and the Ingenuity Pathway Analysis (IPA) to identify a network of genes/pathways regulated by the differentially expressed miRNAs.

Results: 12 BCNR and 30 matched pairs of BCR and BCBM passed the quality control and normalisation processes. Principal component analysis (PCA) performed on 166 miRNAs after QC/normalisation clearly distinguishes the BCNR and the primary BCR from the matched BCBM cases, whereas SAM revealed 58 differentially expressed miRNAs with a 10% FDR (false discovery rate) and an absolute log2 fold-change (FC) &gt;1 between BCNR and BCR and 11 between the matched BCs and BCBMs. Pathway clustering revealed that these differentially expressed miRNAs (10% FDR, log2FC&gt;1) within both BCNR vs BCR and BCR vs BCBM cohorts are highly enriched for genes involved in extracellular matrix (ECM)-receptor interactions, proteoglycans, adherens junctions, TGF-β, p53 and Hippo signalling. IPA identified a network of genes, implicated in the processes of breast cancer invasion and metastasis, regulated by the identified miRNAs, such as, TWIST, MET, TP53, MYC, EZH2, ZEB1, TAGLN and BIRC5. Four of the significantly differentially expressed miRNAs, hsa-miR-132-3p, hsa-miR-199a-5p, hsa-miR-150-5p and hsa-miR-155-5p were present within both cohorts (BCNR vs BCR and BCR vs BCBM) and regulate genes involved in Hippo and TGF-β signalling (DIANA-mirPath v3.0 analysis: p=5.23x10-08 and p=2.67x10-07 respectively).

Conclusion: The current study, utilising a large cohort of paired BCR and BCBM cases, provides novel insight into the molecular mechanisms and role of miRNAs in BCBM. Four miRNAs (hsa-miR-132-3p, hsa-miR-199a-5p, hsa-miR-150-5p and hsa-miR-155-5p) in particular could be potentially used to identify patients with increased risk of developing brain metastasis and help facilitate the development of specific treatments for BCBM, which to date have proved elusive. The miRNAs identified require further exploration as potential biomarkers as well as novel therapeutic targets.

Citation Format: Giannoudis A, Clarke K, Zakaria R, Vareslija D, Farahani M, Rainbow L, Platt-Higgins A, Ruthven S, Brougham K, Rudland PS, Jenkinson MD, Young L, Falciani F, Palmieri C. Identification of microRNAs differentially expressed in brain metastasis secondary to breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-05-02.

Deciphering the transcription factor-microRNA-target gene regulatory network associated with graphene oxide cytotoxicity

Graphene oxide (GO) has recently emanated as a promising material in cancer treatment. To unveil the underlying mechanisms of microRNAs (miRNAs) and potential target genes involved in GO cytotoxicity, we firstly compiled GO-related miRNAs and genes in human cancer cell lines treated with GO from public databases and published works. Besides miRNAs as post-transcriptional regulators of gene expression, transcription factors (TFs) are also the main regulators at the transcriptional level. In the following, we explored the regulatory relationships between miRNAs, target genes, and TFs. Thereafter, a gene regulatory network consisting of GO-responsive miRNAs, GO-responsive genes, and known human TFs was constructed. Then, 3-node regulatory motif types were detected in the resulting network. Among them, miRNA-FFL (feed-forward loop) was identified as a significant motif type. A total of 184 miRNA-FFLs were found and merged to generate a regulatory sub-network. Pathway analysis of the resulting sub-network highlighted adherens junction, focal adhesion, and TGFβ signaling pathways as the major pathways that previous studies demonstrate them to be the affected pathways in GO-treated cells. Functional investigations displayed that miRNAs might be involved in the control of apoptosis through disruption of cell adhesion in response to cytotoxicity. Moreover, GO-cell interactions can lead to miRNA targeting of genes (i.e. Rac1 and RhoA) involved in the cytoskeleton assembly process. These specific toxic properties support biomedical applications of GO, especially for cancer therapy.

Optimizing the hybrid nanostructure of functionalized reduced graphene oxide/silver for highly efficient cancer nanotherapy

Conjugation of Herceptin to the surface of an optimized rGO-PLL/AgNP nanohybrid to achieve an efficient targeted DDS against Her2 positive breast cancer cells.

Effect of videotape for home instruction on the quality of life of tracheostomy patients: a randomized clinical trial

Background: Nowadays, some of the patients, such as the patients with tracheostomy are taken care of at home. The quality of life of these cases may decrease due to the appearance of changes, limitations caused by tracheostomy and improper care. Objectives: This research was performed in order to discover the effect of videotape for home instruction on the quality of life of tracheostomy cases. Patients and Procedure: A quasi-empirical research was carried out on 80 cases by a tracheotomy in Amir Elm Hospital and the Imam Khomeini Medical Center in Tehran. Patients were randomized into two teams of invasion and check through the randomized block design method. At the time of discharge and after a routine training from the clinical staff, the two groups completed a questionnaire regarding the demographic information and the sf-36 quality of life. Then, the intervention team was given a CD containing the routine training for patient care to watch at home. After two months, the participants completed the sf-36 questionnaires again, and the data were entered into SPSS version 20. The information was investigated by using the statistical tests. Findings: The statistical investigation demonstrated that the comparison between the two groups after the intervention in the overall quality of life (p = 0.003) and all the concepts included: the physical role (p = 0.02), the mental role (p = 0.01), energy and fatigue (p = 0.03), motion health (p = 0.005), social functioning (p = 0.06), disorder (p = 0. 001), common health percentage (p = 0.002) and physical functioning (p = 0.001) in the arbitration team, being higher than in the check one. Conclusion: Using the videotape education additionally to routine care has a significant effect on the improvement of the quality of life in these patients. Therefore, the use of this method is recommended as a complementary program for tracheostomy patients.

Prevalence of subclinical hypothyroidism in pregnant women in tehran-iran

BACKGROUND

Maternal subclinical hypothyroidism during pregnancy is associated with various adverse outcomes. Recent consensus guidelines advocate universal thyroid function screening during pregnancy. There are no data from Iran about the prevalence of thyroid hypofunction in pregnancy. This study aims to find the prevalence of thyroid dysfunction.

MATERIALS AND METHODS

In this descriptive cross sectional study, thyrotropin (TSH) was measured in 3158 pregnant women irrespective of gestational age from October 2008-March 2012. If TSH was more than 2.5 mIU/L in the first trimester or more than 3 mIU/L in the second or third trimester, free T4 was measured to diagnose subclinical/ overt hypothyroidism. If serum free T4 was in the normal range (0.7-1.8 ng/dl) the diagnosis was subclinical hypothyroidism and if below the normal range, overt hypothyroidism was diagnosed.

RESULTS

A total of 3158 pregnant women were evaluated. One hundred forty seven of them were diagnosed as hypothyroidism. Subclinical hypothyroidism and overt hypothyroidism were present in 131 (89.1%) and 16 (10.9%) women respectively. Prevalence of subclinical hypothyroidism was 4.15%. Most of the subclinical and overt hypothyroidism cases were diagnosed in the first trimester.

CONCLUSION

It appears logical to check TSH during pregnancy due to the observed prevalence of subclinical hypothyroidism.

Autocrine VEGF mediates the antiapoptotic effect of CD154 on CLL cells

CD154 is an important regulator of chronic lymphocytic leukaemia (CLL)-cell survival. In CLL, high serum levels of VEGF are a feature of advanced disease, and we and others have previously shown that CLL cells produce and secrete this growth factor. Since CD154 stimulates VEGF production in other cell types, and VEGF is known to promote cell survival, we examined whether the cytoprotection of CLL cells by CD154 involves VEGF. We report for the first time that treatment of CLL cells with CD154 results in increased VEGF production and demonstrate involvement of NF-kappaB in this process. Moreover, we show that CD154-induced CLL-cell survival is reduced by anti-VEGF-neutralising antibody and by inhibiting VEGF receptor (VEGFR) signalling with SU5416. However, addition of exogenous VEGF alone or blocking secreted autocrine VEGF had little or no effect on CLL-cell survival. We therefore conclude that CLL-cell cytoprotection in the presence of CD154 requires combined signalling by both CD40 and VEGFR. This combined signalling and resulting cytoprotection were shown to involve NF-kappaB activation and increased survivin production. In conclusion, our findings identify autocrine VEGF as an important mediator of the antiapoptotic effect of CD40 ligation, and thus provide new insights into CLL-cell rescue by CD154 in lymphoreticular tissues.

Quantification of the selective retention of palladium octabutoxynaphthalocyanine, a potential photothermal drug, in mouse tissues

Palladium octabutoxynaphthalocyanine (PdNc(OBu)8) is a potential photothermal therapy (PTT) agent, absorbing strongly in the near-infrared region with no ability to induce photodynamic-type sensitisation (unlike many related napthalocyanines). We report here on the application of high pressure liquid chromatography (HPLC) with near-infrared absorption detection for the determination of the tissue accumulation and clearance of PdNc(OBu)8 in a tumour-bearing mouse model (Balb/c mice with EMT6 carcinoma tumour). Due to its insolubility in aqueous-based solvents, the drug was delivered intraperitoneally in a Cremophor-containing vehicle. Good selective accumulation of the drug into the tumour versus muscle or skin is observed, with the best combination of selectivity and tumour concentration occurring at 24-72 h after drug administration. Clearance times are quite long. Comparison with other similar drugs as reported in the literature indicates that the Cremophor-containing vehicle is likely in large part responsible for the observed pharmacokinetic behaviour. This drug shows potential for PTT and will be investigated further for therapy in this animal model.

Kinetic studies of aflatoxin B1-glutathione conjugate formation in liver and kidneys of adult and weanling rats

Aflatoxin B1(AFB1)-glutathione(GSH) conjugation is the major pathway for the detoxification of aflatoxin metabolites. This reaction is catalysed by GSH S-transferase (GST) and play a major role in modulation of AFB1 adduct formation to nuclear DNA. Changes recorded in hepatic GST activity during development of rats can alter the balance between AFB1-GSH conjugation and AFB1-DNA adduct formation. Measurment of cytosolic GST using 1-chloro-2,4-dinitrobenzene (CDNB) as the substrate showed that the enzyme activity is initially lower in weanling tissues as compared to that of adults. But nevertheless hepatic and renal cytosolic GST activity is increased significantly in growing rats pretreated with AFB1. Kinetic studies of AFB1-GSH conjugate formation in kidneys and livers of the two-age groups of rats treated with a single i.p. dose of AFB1 (400 microg/kg b.w.) revealed that at the end of 24 h of AFB1 administration the rate of the conjugate formation in kidneys of immature rats was approximately twice of that measured in adults. Age-related differences in the GST activity as well as AFB1-GSH conjugation was more pronounced in kidneys. The conjugate formation in kidneys of growing rats during 6-24 h following AFB1 administration shows that urinary excretion of aflatoxin metabolites is relatively rapid in growing rats. The major portion of the AFB1-GSH is formed in liver but contribution of the renal tissue to the formation of detoxification metabolites can not be ruled out. These data demonstrate that aflatoxin metabolites are eliminated more efficiently from kidneys of a growing rat. AFB1-induced GST induction in renal tissues of growing animals during 24 h of the carcinogen administration could be considered as an important mechanism for GSH conjugate formation and aflatoxin detoxification. Therefore GST induction in response to hepatotoxic drugs can confer resistance to young animals being exposed for the first time to such drugs. It is also worthmentioning that the GST activity measured before AFB1 administration does not reflect the rate of AFB1 detoxification via GSH conjugation.

MALDI-TOF MS analysis of a library of polymerizable cyclodextrin derivatives

Polymerizable cyclodextrin derivatives (PCDs) have been proposed as candidates for use in dental therapeutics (Bowen, 1996; Bowen and Reed, 1997). Here, PCD "libraries" were synthesized by quasi-random reactions of 6 moles of methacrylic anhydride plus 6 moles of cyclic glutaric anhydride per mole of beta-cyclodextrin (BCD) in solution. BCD has 21 reactive sites on each of its molecules. These proportions were based on probability calculations, which predicted that the products should have a minimum of 2 polymerizable substituents and acidic ligand groups on practically every one of the diverse product molecules. Matrix-assisted laser desorption/ionization (MALDI) time of flight (TOF) mass spectrometry (MS) gave valuable information regarding the masses of molecular ions representing the molecules that made up the PCD libraries. For the MALDI-TOF MS analyses, small samples were analyzed by the successive application of 3 solutions to the sample holder: the matrix in acetone, the products in water, and sodium trifluoroacetate in water. The resulting spectra had > 40 envelopes of mass peaks above background. The ionic-abundance peak heights had quasi-Gaussian configurations, with central peaks having masses in the neighborhood of 2000 g/mol (Daltons). Regardless of structural permutations within each peak, the range of these peaks was between about 1500 g/mol and 2900 g/mol. This range of masses was in accord with, but perhaps somewhat more narrow than, that predicted by the statistical method, which was based on equal reactivity of all hydroxyl groups. Analysis by MALDI-TOF MS gave valuable data regarding the masses, structures, and characteristics of the products formed and provided unanticipated information to facilitate improvements in future PCD syntheses.

Comparison of simultaneous administration of lithium with L-NAME or L-arginine on morphine withdrawal syndrome in mice

Due to the claim that chronic administration of lithium or L-N(G)-nitroarginine methyl ester (L-NAME), a nitric oxide synthase (NOS) inhibitor reduces morphine withdrawal syndrome, the effects of chronic administration of lithium, L-NAME, or L-arginine (L-Arg), a precursor of NO, alone or co-administration of lithium with L-Arg or L-NAME, on naloxone-precipitated withdrawal syndrome and physical dependence development to morphine in mice chronically treated with morphine, were evaluated. Morphine dependency was induced by the intraperitoneal injection (i.p.) of morphine (10 mg/kg), once daily for 7 days. Physical dependence to morphine was observed by precipitating an abstinence syndrome with naloxone (2 mg/kg, i.p.). Chronic administration of L-NAME (10 mg/kg, i.p., once daily, for 7 days after 10 days of receiving only tap water and food prior to naloxone), decreased all withdrawal signs significantly, while L-Arg (200 mg/kg, as above) increased only some withdrawal signs significantly in morphine-dependent mice. Chronic administration of lithium (600 mg/kg, in drinking water) alone or co-administration of lithium (as above) with L-NAME (10 mg/kg) or L-Arg (200 mg/kg, i.p., once daily) for 7 days after 10 days of receiving only lithium (as above) and food, decreased all withdrawal signs and physical dependence significantly in morphine-dependent mice. The results obtained indicate that co-administration of L-NAME with lithium increases the effect of lithium or L-NAME alone, on withdrawal signs, but this increase is not significantly different as compared to chronic lithium or L-NAME administration alone; while co-administration of L-Arg with lithium decreases the effects of lithium on withdrawal signs and this decrease is not significant as compared to chronic lithium administration alone. These findings indicate that nitric oxide may be involved in modulation of naloxone-induced withdrawal syndrome, and treatment with lithium could have some effect on this system. Copyright 2000 John Wiley & Sons, Ltd.

Decrease in erythrocyte:plasma lithium ratio by concurrent administration of psychotropic drugs and lithium in mice

1. Previous studies paying attention to concurrent use of lithium (Li+) with a neuroleptic were not done under constant and controlled conditions. We were therefore encouraged to do a prospectively controlled study, presuming constant relevant factors, on concomitant use of Li+ with neuroleptic as well as other psychotropic agents. 2. The effects of concurrent administration of chlorpromazine, haloperidol, imipramine and carbamazepine with Li+ on the erythrocyte:plasma Li+ ratio and the intraerythrocyte Li+ concentration were studied in mice by using a new, direct method of measuring erythrocyte Li+ concentration. 3. All of the foregoing agents with the exception of carbamazepine were observed to significantly decrease the Li+ ratio. 4. Lack of any significant effect by carbamazepine on Li+ transport may be an indication of this drug's efficacy as a supplement in Li+ therapy of bipolar affective disorders. 5. The decrease in Li+ ratio observed with chlorpromazine, haloperidol and imipramine may be explained through the mechanism by which these drugs stabilize the cell membrane and consequently affect Li+ transport in erythrocytes. 6. Moreover, our study proves that, although the Li(+)-sodium countertransport mechanism does not exist in mice, the same interaction between Li+ and other psychotropic drugs is seen. It can be concluded that such interaction is not mediated through Li(+)-sodium countertransport. 7. It is suggested that, with concurrent use of a psychotropic drug and Li+, the amount of intraerythrocyte Li+ concentration be measured, instead of relying on the plasma Li+ concentration alone.

Regulation of histamine H1 receptor coupling by dexamethasone in human cultured airway smooth muscle

1. The regulation of histamine-induced [3H]-inositol phosphate and intracellular calcium responses in human cultured airway smooth muscle cells was studied. 2. Histamine induced concentration-dependent [3H]-inositol phosphate formation (EC50 4 microM). This response was inhibited by a range of selective H1 receptor antagonists but not by the H2-selective antagonist, tiotidone or the H3 receptor-selective antagonist, thioperamide, indicating that an H1 receptor is involved in this response in human cultured airway smooth muscle cells. 3. Preincubation of human cultured airway smooth muscle cells with concentrations of dexamethasone > 10 nM for 22 h produced concentration-dependent inhibition of histamine-induced inositol phosphate formation. The maximum inhibition observed was 45% of the response in control cells. The inhibitory effect of dexamethasone was itself reversed by prior exposure to the glucocorticoid receptor antagonist, RU38486 (10 microM). Preincubation for 22 h with 1 microM dexamethasone produced inhibition of the inositol phosphate response to histamine to all concentrations of histamine inducing significant inositol phosphate formation in these cells. In contrast, the response to the G protein activator, NaF (0.1-20 mM) was unaltered by preincubation with dexamethasone. 4. Preincubation of human airway smooth muscle cells with 1 microM dexamethasone for time periods of < 6 h failed to inhibit histamine-induced inositol phosphate formation in human airway smooth muscle cells. 5. Histamine also induced concentration-dependent elevation of intracellular calcium levels in Fura 2-loaded human airway smooth muscle cells. This response was inhibited by preincubation with 1 microM dexamethasone. 6. We conclude that signal transduction through the H1 receptor in human airway smooth muscle is subject to regulation by dexamethasone and that this may in part account for the protective effect of dexamethasone against spasmogen-induced contractile responses in the airways.

New surface-active comonomer for adhesive bonding

Previous studies have indicated that chemical and physical characteristics of aromatic amines can be influenced by the nature of their substituents. The experimental question examined in the present study relates to the effects of replacing specific hydrogen atoms with methyl groups in a surface-active comonomer utilized in adhesive bonding protocols. N-2-propionic acid-N-3-(2-hydroxy-1-methacryloxy)propyl-3,5-dimethylaniline sodium salt (N35A) was synthesized by an addition reaction of glycidyl methacrylate with the sodium salt of N-reaction of glycidyl methacrylate with the sodium salt of N-(3,5-dimethylphenyl)alanine, which was formed by alkaline hydrolysis of ethyl-N-(3,5-dimethylphenyl)alanate that was prepared by condensation of ethyl-2-bromopropionate with 3,5-dimethylaniline. 1H and 13C NMR spectra and analysis by mass spectroscopy were consistent with N35A after it had been recrystallized from acetone. Color stability and adhesion-promoting capability of N35A were compared with those of N-2-acetic acid-N-3-(2-hydroxy-1-methacryloxy)propyl-4-methylanaline sodium salt (Na-NTG-GMA), the latter being widely used in commercial bonding formulations. Both N35A and Na-NTG-GMA polymerized within a few minutes at 23 degrees C when dissolved in aliquots from a stock solution containing benzene 85 wt%, ethanol 14 wt%, and benzoyl peroxide 1.0 wt%; but with each at 0.018 molal concentration, the N35A suspension was more color-stable than that of the Na-NTG-GMA. In the protocol used, shear bond strengths of a hybrid composite to human dentin with N35A were 30.2 MPa, SD = 7.5 MPa, and with Na-NTG-GMA, 29.7 MPa, SD = 11.8 MPa(n = 7 each; t test, p = 0.93).

New method for shielding electron beams used for head and neck cancer treatment

Shields and stents of metals with high atomic number, which are custom cast in molds from the melt, are the materials most widely used to protect surrounding tissues during treatment of skin or oral lesions with therapeutic electron beams. An improved fabrication method is to mix a polysiloxane-metal composite, which is readily cast at room temperature by combining a metal-powder/polysiloxane resin mixture with a hardening catalyst. The purpose of the present study is to compare the shielding effectiveness of two different metal-polysiloxane composites with that of conventional cast Lipowitz metal (50.1% Bi, 26.6% Pb, 13.3% Sn, 10% Cd). Also, a 2(3) factorial experiment was run to investigate the effects and interactions of metal particle size (20-microns vs 100-microns diameter), the atomic weight of the metal (304 stainless steel vs 70% Ag, 30% Cu alloy), and the presence or absence of a layer of unfilled polymer added to the forward-scatter side of the shield. The composites of different thicknesses were made by blending 90% (w/w) metal powder separately with 10% polysiloxane base and catalyst. A thin GafChromic dosimeter film was placed between the shielding material and a polystyrene base to measure the radiation shielding effect of composite disc samples irradiated with a 6-MeV electron beam normal to the flat surface of the disc. The results show that composite shields with the metal of higher atomic weight and density (Ag-Cu) combined with an additional unfilled layer are more effective than the stainless-steel composite with a similar additional unfilled layer, in terms of diminishing the dose at the surface of the polystyrene backing material.(ABSTRACT TRUNCATED AT 250 WORDS)

Metal-polysiloxane shields for radiation therapy of maxillo-facial tumors

In the treatment of some head and neck lesions with high-intensity radiation (teletherapy), an essential procedure is the application of an individually customized shielding appliance, which is designed, modeled, and formed into a working extra- or intraoral stent for the purpose of sparing healthy tissues. The present state of the art is slow and technique intensive, which can add to patient discomfort and inconvenience during molding and fabrication. A new formulation is described, which offers speed and ease of forming a moldable composite stent especially for intraoral use. Interleaved stacks of calibrated thin radiochromic film strips and soft-tissue-simulating plastic (polystyrene) layers gave a means of mapping one- or two-dimensional profiles of dose distributions adjacent to the high-density shielding materials using a spectrophotometer equipped with a gel scanner or a scanning laser-beam microdensitometer. Tests using collimated gamma-ray beams from a 60Co teletherapy unit were made in order to measure the dose distribution near interfaces of tissue-simulating polymer and the composite stent material with and without mixtures of metals (Ag-Cu and Sn-Sb). These results show that quickly formed composites made of a flexible resin with high concentrations of powdered spherical metal alloys provide effective custom-designed shielding, and, with a thin overlayer of the resin without metal, a diminished back-scattered radiation dose to normal tissues. An example of a successful formulation is a mixture of 90% by weight Ag-Cu alloy powder in a vinyl polysiloxane resin. This material is a moldable putty which, upon polymerization, forms a rigid elastomeric material, providing a half-value layer of approximately 2.5 to 2.8 cm for a gamma-ray beam from a 60Co source.

The effect of catalyst structure on the synthesis of a dental restorative monomer

The addition product of 2-hydroxyethyl methacrylate (HEMA) and pyromellitic dianhydride (PMDA), known as PMDM, is a mixture of two structural isomers. The para PMDM isomer--currently used in mediating adhesive bonding of restorative materials to hard tooth tissues--is a crystalline solid. The meta isomer is a liquid. In the synthesis of PMDM, the para isomer, which can be purified by crystallization, is usually present to the extent of only 50% of the product mixture. The effect of the amine catalyst structure was studied relative to its role in increasing the yield of the para isomer, either by a reduction in the amount of the meta isomer or by an increase in the extent of overall reaction. The chemical structure of the amine catalyst had an important role in the synthesis of PMDM and influenced the ratio of the isomers. Among aliphatic amines, especially noteworthy as catalysts that gave excellent yields of the para isomer in high purity were N,N-di-isopropyl-ethylamine and hexamethylenetetramine.

Measurement of absorbed doses near metal and dental material interfaces irradiated by x- and gamma-ray therapy beams

Soft-tissue damage adjacent to dental restorations is a deleterious side effect of radiation therapy which is associated with low-energy electron scatter from dental materials of high electron density. This study was designed to investigate the enhancement of dose to soft tissue (or water) close to high electron-density materials and to measure the detailed lateral and depth-dose profiles in soft-tissue-simulating polymer adjacent to planar interfaces of several higher atomic-number materials: 18-carat gold dental casting alloy; Ag-Hg dental amalgam alloy; Ni-Cr dental casting alloy; and natural human tooth structure. Interleaved stacks of calibrated thin radiochromic dosimeter films and tissue-simulating polymer were used for these measurements. Assemblies of these polymer-dosimeter stacks on both sides of the dental materials were irradiated in one fixed direction by collimated 60Co gamma-ray or 10 MV x-ray beams directed perpendicularly to the material interfaces. In another test, designed to simulate more closely therapeutic treatment conditions, a phantom constructed on both sides of a row of restored and unrestored whole teeth (restoration materials: gold alloy crown; Ni-Cr alloy crown; Ag-Hg mesial-occlusal-distal (MOD) amalgam filling; unrestored tooth) was irradiated in one fixed direction by the collimated photon beams. Results indicate that the dose-enhancement in 'tissue' is as great as a factor of 2 on the backscatter side adjacent to gold and a factor of 1.2 adjacent to tooth tissue, but is insignificant on the forward-scatter side because of the predominant effect of attenuation by the high-density, high atomic-number absorbing material.

Hydroxyl radical induced cross-linking between phenylalanine and 2-deoxyribose

Hydroxy radicals induce cross-linking between phenylalanine (Phe) and 2-deoxyribose (dR) via formation of corresponding free radical intermediates. The cross-linked products were separated and identified by capillary gas chromatography-mass spectrometry. When phenylalanine and 2-deoxyribose radicals were generated in a 1:1 ratio, the predominant interaction was between Phe and dR radicals while the Phe-Phe and dR-dR cross-links were less abundant. The newly discovered cross-link between 2-deoxyribose and phenylalanine may serve as a model for radiation or free radical induced cross-linking between DNA and proteins and in general between sugar moieties and amino acids.