Drug-Induced Hypoglycemia in Neonates Born to Nondiabetic Women Treated with Medications during the Pregnancy or the Labor: A Systematic Review of the Literature.

The prompt identification of at-risk newborns for drug-induced hypoglycemia can minimize the risk for adverse side effects, inappropriate investigations, and considerable unnecessary costs. Existing literature discusses drug-induced hypoglycemia, but a systematic description of neonatal hypoglycemia induced or exacerbated by maternal medications is missing. We reviewed the association between neonatal hypoglycemia and maternal medications. We systematically searched the literature according to the PICOS model on drug-induced hypoglycemia in neonates born to nondiabetic women treated with medications during the pregnancy or the labor. The main outcomes of the review were: (1) prevalence of hypoglycemia, (2) risk factors and potential confounders, (3) time at onset and severity of hypoglycemia, (4) dose-response gradient, (5) metabolic features of hypoglycemia, (6) modalities to treat hypoglycemia, and (7) quality of the studies. We included 69 studies in this review and we identified 11 groups of maternal drugs related to neonatal hypoglycemia. Results were classified for each outcome. Our review aims at supporting clinicians in the identification of the newborn at risk for hypoglycemia and in the differential diagnosis of neonatal hypoglycemia. Further studies are necessary to assess the risk of neonatal hypoglycemia associated with common maternal medications. KEY POINTS: · A systematic description of neonatal hypoglycemia induced or exacerbated by maternal medications is missing.. · In our review we identified 11 groups of maternal drugs related to neonatal hypoglycemia.. · Our review aims at supporting clinicians in the identification of the newborn at risk for hypoglycemia..

Drug-induced hyperinsulinemic hypoglycemia: An update on pathophysiology and treatment.

The initial step for the differential diagnosis of hypoglycemia is to determine whether it is hyperinsulinemic or non hyperinsulinemic. Existing literature discusses drug-related hypoglycemia, but it misses a focus on drug-induced hyperinsulinemic hypoglycemia (DHH). Here we reviewed the association existing between drugs and hyperinsulinemic hypoglycemia. We primarily selected on the main electronic databases (MEDLINE, EMBASE, Web of Science, and SCOPUS) the reviews on drug-induced hypoglycemia. Among the drugs listed in the reviews, we selected the ones linked to an increase in insulin secretion. For the drugs missing a clear association with insulin secretion, we investigated the putative mechanism underlying hypoglycemia referring to the original papers. Our review provides a list of the most common agents associated with hyperinsulinemic hypoglycemia (HH), in order to facilitate both the recognition and the prevention of DHH. We also collected data about the responsiveness of DHH to diazoxide or octreotide.

Analysis of current data on the use of topical mTOR inhibitors in the treatment of facial angiofibromas in tuberous sclerosis complex-An update.

Tuberous sclerosis complex (TSC) is an autosomal dominant neurocutaneous syndrome causing hamartomatous growths in multiple organs. Facial angiofibromas occur in up to 80% of patients and can be highly disfiguring. Treatment for these lesions is challenging. Recently, topical rapamycin has been proposed as an effective option to treat angiofibromas but a commercially available compound has not yet been developed in Europe. We conducted a retrospective review with the aim to update the current data on the use of topical rapamycin in the treatment of angiofibromas in TSC, focusing on the optimal concentration and trying to establish which vehicle should be preferred. Thirty-nine reports describing the use of topical rapamycin in the treatment of angiofibromas in TSC were considered, involving a total of 483 patients. An improvement of the lesions has been shown in over 90% of subjects, particularly if the treatment was started at early stages. Several different formulations (ointment, gel, solution and cream) with a wide range of concentrations (0.003%-1%) were proposed, of which a pharmacological analysis has also been performed. Topical rapamycin can be considered an effective and safe option for the treatment and the prevention of facial angiofibromas in younger patients, but the best formulation has yet to be established. Our review demonstrates that ointment and gel should be preferred, but it is not clear which concentration is optimal. However, according to this study, the 0.1% concentration represents the first choice. Long-term and comparative studies between topical rapamycin formulations are required in order to establish which treatment has a better outcome and lower recurrence rate.

Genetic Variation among Pharmacogenes in the Sardinian Population.

Pharmacogenetics (PGx) aims to identify the genetic factors that determine inter-individual differences in response to drug treatment maximizing efficacy while decreasing the risk of adverse events. Estimating the prevalence of PGx variants involved in drug response, is a critical preparatory step for large-scale implementation of a personalized medicine program in a target population. Here, we profiled pharmacogenetic variation in fourteen clinically relevant genes in a representative sample set of 1577 unrelated sequenced Sardinians, an ancient island population that accounts for genetic variation in Europe as a whole, and, at the same time is enriched in genetic variants that are very rare elsewhere. To this end, we used PGxPOP, a PGx allele caller based on the guidelines created by the Clinical Pharmacogenetics Implementation Consortium (CPIC), to identify the main phenotypes associated with the PGx alleles most represented in Sardinians. We estimated that 99.43% of Sardinian individuals might potentially respond atypically to at least one drug, that on average each individual is expected to have an abnormal response to about 17 drugs, and that for 27 drugs the fraction of the population at risk of atypical responses to therapy is more than 40%. Finally, we identified 174 pharmacogenetic variants for which the minor allele frequency was at least 10% higher among Sardinians as compared to other European populations, a fact that may contribute to substantial interpopulation variability in drug response phenotypes. This study provides baseline information for further large-scale pharmacogenomic investigations in the Sardinian population and underlines the importance of PGx characterization of diverse European populations, such as Sardinians.

The Role of Omics Approaches to Characterize Molecular Mechanisms of Rare Ovarian Cancers: Recent Advances and Future Perspectives.

Rare ovarian cancers are ovarian cancers with an annual incidence of less than 6 cases per 100,000 women. They generally have a poor prognosis due to being delayed diagnosis and treatment. Exploration of molecular mechanisms in these cancers has been challenging due to their rarity and research efforts being fragmented across the world. Omics approaches can provide detailed molecular snapshots of the underlying mechanisms of these cancers. Omics approaches, including genomics, transcriptomics, proteomics, and metabolomics, can identify potential candidate biomarkers for diagnosis, prognosis, and screening of rare gynecological cancers and can aid in identifying therapeutic targets. The integration of multiple omics techniques using approaches such as proteogenomics can provide a detailed understanding of the molecular mechanisms of carcinogenesis and cancer progression. Further, omics approaches can provide clues towards developing immunotherapies, cancer recurrence, and drug resistance in tumors; and form a platform for personalized medicine. The current review focuses on the application of omics approaches and integrative biology to gain a better understanding of rare ovarian cancers.

Sex-Biased Expression of Pharmacogenes across Human Tissues.

Individual response to drugs is highly variable and largely influenced by genetic variants and gene-expression profiles. In addition, it has been shown that response to drugs is strongly sex-dependent, both in terms of efficacy and toxicity. To expand current knowledge on sex differences in the expression of genes relevant for drug response, we generated a catalogue of differentially expressed human transcripts encoded by 289 genes in 41 human tissues from 838 adult individuals of the Genotype-Tissue Expression project (GTEx, v8 release) and focused our analysis on relevant transcripts implicated in drug response. We detected significant sex-differentiated expression of 99 transcripts encoded by 59 genes in the tissues most relevant for human pharmacology (liver, lung, kidney, small intestine terminal ileum, skin not sun-exposed, and whole blood). Among them, as expected, we confirmed significant differences in the expression of transcripts encoded by the cytochromes in the liver, CYP2B6, CYP3A7, CYP3A5, and CYP1A1. Our systematic investigation on differences between male and female in the expression of drug response-related genes, reinforce the need to overcome the sex bias of clinical trials.

Safety of switching between rituximab biosimilars in onco-hematology.

Comparable clinical efficacy and safety of the reference rituximab (MABTHERA) and its biosimilars has been established in randomized trials. However, safety concerns are often raised when switching from reference to biosimilar products and between different biosimilars. In this prospective observational study we aimed at evaluating the safety of switching between reference and biosimilar rituximab (TRUXIMA and RIXATHON) at Trento General Hospital (Italy). All patients (n = 83) with Non Hodgkin's Lymphoma (NHL, n = 72) and Chronic Lymphocytic Leukemia (CLL, n = 11) who received rituximab between March 2018 and March 2019 were asked to take part in the study. In 2017 and 2018 two tenders were carried out and two different biosimilars became available in the hospital, these were used sequentially. Thus, patients with or without previous treatments with the originator rituximab either received a biosimilar or were switched between different biosimilars. The incidence of adverse events in these groups of patients is described. The study population received 465 rituximab infusions and all received biosimilars. Fifty patients (60%) experienced at least one switch between different biosimilars or between rituximab originator and biosimilar, whereas 33 (40%) received one of the two biosimilars and one patient received reference rituximab. Adverse events (n = 146) were reported in 71 patients (84.5%). Treatment-related grade 3-4 events were reported in 5 patients (5.9%), whereas grade 1 rituximab related infusion events were observed in 6 patients (7.1%). No safety signal emerged in association with the use of a specific biosimilar nor with the practice of switching. Adverse events were similar, in terms of seriousness and frequency, to those described in the literature, providing further support to the clinical safety of rituximab biosimilars.

Histologic subtyping affecting outcome of triple negative breast cancer: a large Sardinian population-based analysis.

BACKGROUND: Triple Negative breast cancer (TNBC) includes a heterogeneous group of tumors with different clinico-pathological features, molecular alterations and treatment responsivity. Our aim was to evaluate the clinico-pathological heterogeneity and prognostic significance of TNBC histologic variants, comparing "special types" to high-grade invasive breast carcinomas of no special type (IBC-NST). METHODS: This study was performed on data obtained from TNBC Database, including pathological features and clinical records of 1009 TNBCs patients diagnosed between 1994 and 2015 in the four most important Oncology Units located in different hospitals in Sardinia, Italy. Kaplan-Meier analysis, log-rank test and multivariate Cox proportional-hazards regression were applied for overall survival (OS) and disease free survival (DFS) according to TNBC histologic types. RESULTS: TNBC "special types" showed significant differences for several clinico-pathological features when compared to IBC-NST. We observed that in apocrine carcinomas as tumor size increased, the number of metastatic lymph nodes manifestly increased. Adenoid cystic carcinoma showed the smallest tumor size relative to IBC-NST. At five-year follow-up, OS was 92.1, 100.0, and 94.5% for patients with apocrine, adenoid cystic and medullary carcinoma, respectively; patients with lobular and metaplastic carcinoma showed the worst OS, with 79.7 and 84.3%, respectively. At ten-years, patients with adenoid cystic (100.0%) and medullary (94.5%) carcinoma showed a favourable prognosis, whereas patients with lobular carcinoma showed the worst prognosis (73.8%). TNBC medullary type was an independent prognostic factor for DFS compared to IBC-NST. CONCLUSIONS: Our study confirms that an accurate and reliable histopathologic definition of TNBC subtypes has a significant clinical utility and is effective in the therapeutic decision-making process, with the aim to develop innovative and personalized treatments.

Nasopharyngeal swab collection in the suspicion of Covid-19.

RT-PCR detection of SARS-CoV-2 mRNA on nasopharyngeal swab is the standard for diagnosing active Covid-19 disease in asymptomatic subjects and in symptomatic patients without the typical radiological findings. Nasopharyngeal swabbing appears a trivial procedure, still an inappropriate nasopharyngeal sampling, performed by untrained operators, can be a relevant cause of false negative findings with a clear negative impact on the effort to control the epidemic and, when PPE is not properly used, this can expose healthcare workers and patients to risks of contagion.

Prevalence of multiple sclerosis in Sardinia: A systematic cross-sectional multi-source survey.

BACKGROUND: Partial surveys in sub-regions of Sardinia have suggested a high prevalence of multiple sclerosis (MS) on the island, relative to other Mediterranean populations. We assessed the island-wide prevalence of MS and its detailed distribution in Sardinia. METHODS: The study population consisted of 5677 MS patients, 1735 men and 3942 women, living in Sardinia. Neurologists retrospectively examined electronic and paper-based records of patients with a diagnosis of MS. The data were then linked to the administrative health information systems. Crude, age-, and sex-specific prevalence estimates of disease were calculated. RESULTS: The overall age-adjusted MS prevalence was 330 per 100,000 (95% confidence interval (CI) 321-338) in individuals older than 15 years, 447 in women (95% CI 433-461), and 205 in men (95% CI 195-214). The prevalence was highest in the Ogliastra and Nuoro districts, respectively, 425 (95% CI 372-478) and 419 (95% CI 387-451), and lowest in the Olbia-Tempio district, 217 (95% CI 195-239). Most cases had relapsing-remitting MS (79.3%), 16.3% had secondary-progressive MS, and 4.4% had primary-progressive MS. CONCLUSION: These prevalence are among the highest reported so far worldwide. They provide estimates for comparative analyses in other populations and are essential for public health interventions.

Kidney size in relation to ageing, gender, renal function, birthweight and chronic kidney disease risk factors in a general population.

BACKGROUND: The relationship of kidney size to ageing, kidney function and kidney disease risk factors is not fully understood. METHODS: Ultrasound length and parenchymal kidney volume were determined from a population-based sample of 3972 Sardinians (age range 18-100 years). We then identified the subset of 2256 'healthy' subjects to define age- and sex-specific reference ranges (2.5-97.5 percentile) of kidney volume. Logistic regression (accounting for family clustering) was used to identify the clinical characteristics associated with abnormally large kidneys or abnormally small kidneys. RESULTS: In the healthy subset, kidney volume and length increased up to the fourth to fifth decade of life followed by a progressive decrease in men, whereas there was a gradual kidney volume decrease throughout the lifespan of women. In the whole sample, independent predictors of lower kidney volume (<2.5 percentile for age and sex) were male sex, low body mass index, short height, low waist:hip ratio and high serum creatinine (SCr); the independent predictors of larger kidney volume (>97.5 percentile for age and sex) were younger age, female sex, diabetes, obesity, high height, high waist:hip ratio and lower SCr. Estimated heritability for kidney volume was 15%, and for length 27%; kidney volume correlated strongly with birthweight. CONCLUSIONS: Overall, in a general healthy population, kidney measures declined with age differently in men and women. The determinants of kidney parenchymal volume include genetic factors and modifiable clinical factors.

Clinical and pathological factors influencing survival in a large cohort of triple-negative breast cancer patients.

BACKGROUND: To provide further information on the clinical and pathological prognostic factors in triple-negative breast cancer (TNBC), for which limited and inconsistent data are available. METHODS: Pathological characteristics and clinical records of 841 TNBCs diagnosed between 1994 and 2015 in four major oncologic centers from Sardinia, Italy, were reviewed. Multivariate hazard ratios (HRs) for mortality and recurrence according to various clinicopathological factors were estimated using Cox proportional hazards models. RESULTS: After a mean follow-up of 4.3 years, 275 (33.3%) TNBC patients had a progression of the disease and 170 (20.2%) died. After allowance for study center, age at diagnosis, and various clinicopathological factors, all components of the TNM staging system were identified as significant independent prognostic factors for TNBC mortality. The HRs were 3.13, 9.65, and 29.0, for stage II, III and IV, respectively, vs stage I. Necrosis and Ki-67 > 16% were also associated with increased mortality (HR: 1.61 and 1.99, respectively). Patients with tumor histotypes other than ductal invasive/lobular carcinomas had a more favorable prognosis (HR: 0.40 vs ductal invasive carcinoma). No significant associations with mortality were found for histologic grade, tumor infiltrating lymphocytes, and lymphovascular invasion. Among lymph node positive TNBCs, lymph node ratio appeared to be a stronger predictor of mortality than pathological lymph nodes stage (HR: 0.80 for pN3 vs pN1, and 3.05 for >0.65 vs <0.21 lymph node ratio), respectively. Consistent results were observed for cancer recurrence, except for Ki-67 and necrosis that were not found to be significant predictors for recurrence. CONCLUSIONS: This uniquely large study of TNBC patients provides further evidence that, besides tumor stage at diagnosis, lymph node ratio among lymph node positive tumors is an additional relevant predictor of survival and tumor recurrence, while Ki-67 seems to be predictive of mortality, but not of recurrence.

Myelodysplastic Syndromes and Iron Chelation Therapy.

Over recent decades we have been fortunate to witness the advent of new technologies and of an expanded knowledge and application of chelation therapies to the benefit of patients with iron overload. However, extrapolation of learnings from thalassemia to the myelodysplastic syndromes (MDS) has resulted in a fragmented and uncoordinated clinical evidence base. We're therefore forced to change our understanding of MDS, looking with other eyes to observational studies that inform us about the relationship between iron and tissue damage in these subjects. The available evidence suggests that iron accumulation is prognostically significant in MDS, but levels of accumulation historically associated with organ damage (based on data generated in the thalassemias) are infrequent. Emerging experimental data have provided some insight into this paradox, as our understanding of iron-induced tissue damage has evolved from a process of progressive bulking of organs through high-volumes iron deposition, to one of 'toxic' damage inflicted through multiple cellular pathways. Damage from iron may, therefore, occur prior to reaching reference thresholds, and similarly, chelation may be of benefit before overt iron overload is seen. In this review, we revisit the scientific and clinical evidence for iron overload in MDS to better characterize the iron overload phenotype in these patients, which differs from the classical transfusional and non-transfusional iron overload syndrome. We hope this will provide a conceptual framework to better understand the complex associations between anemia, iron and clinical outcomes, to accelerate progress in this area.

Analysis of PIK3CA Mutations and Activation Pathways in Triple Negative Breast Cancer.

BACKGROUND: Triple Negative Breast Cancer (TNBC) accounts for 12-24% of all breast carcinomas, and shows worse prognosis compared to other breast cancer subtypes. Molecular studies demonstrated that TNBCs are a heterogeneous group of tumors with different clinical and pathologic features, prognosis, genetic-molecular alterations and treatment responsivity. The PI3K/AKT is a major pathway involved in the regulation of cell survival and proliferation, and is the most frequently altered pathway in breast cancer, apparently with different biologic impact on specific cancer subtypes. The most common genetic abnormality is represented by PIK3CA gene activating mutations, with an overall frequency of 20-40%. The aims of our study were to investigate PIK3CA gene mutations on a large series of TNBC, to perform a wider analysis on genetic alterations involving PI3K/AKT and BRAF/RAS/MAPK pathways and to correlate the results with clinical-pathologic data. MATERIALS AND METHODS: PIK3CA mutation analysis was performed by using cobas® PIK3CA Mutation Test. EGFR, AKT1, BRAF, and KRAS genes were analyzed by sequencing. Immunohistochemistry was carried out to identify PTEN loss and to investigate for PI3K/AKT pathways components. RESULTS: PIK3CA mutations were detected in 23.7% of TNBC, whereas no mutations were identified in EGFR, AKT1, BRAF, and KRAS genes. Moreover, we observed PTEN loss in 11.3% of tumors. Deregulation of PI3K/AKT pathways was revealed by consistent activation of pAKT and p-p44/42 MAPK in all PIK3CA mutated TNBC. CONCLUSIONS: Our data shows that PIK3CA mutations and PI3K/AKT pathway activation are common events in TNBC. A deeper investigation on specific TNBC genomic abnormalities might be helpful in order to select patients who would benefit from current targeted therapy strategies.

Role of community pharmacists in the detection of potentially inappropriate benzodiazepines prescriptions for insomnia.

BACKGROUND: The appropriate management of chronic insomnia is crucial and prescribing of hypnotic drugs is common. Regular and prolonged use of hypnotics should be avoided because of the risk of tolerance to effects, dependence and an increased risk of adverse events. In 2012, updated Beers criteria for potentially inappropriate medication in older adults suggested to avoid all benzodiazepines in older adults to treat insomnia. In addition, successful discontinuation may result in improvements on cognitive and psychomotor function, particularly in older people. OBJECTIVE: To investigate the appropriateness of benzodiazepines prescription for insomnia and explore the role that community pharmacists can have in identifying signals of potential inappropriate drug prescriptions. SETTING: Community pharmacies in Italy. METHOD: This is an observational study conducted in 8 community pharmacies. Each pharmacist was asked to interview a sample of patients with the prescriptions of at least one benzodiazepine and to complete a minimum data set collecting information about socio-demographic characteristics, drug indication, duration of drug prescription, number of hypnotic-drugs, previous attempt to drug-discontinuation, preference of patients about benzodiazepine withdrawal and modality of drug tapering. Main outcome measure Indications, treatment duration, dosage and drug discontinuation attempts and modalities. RESULTS: A total of 181 participants were interviewed. About half of respondents (n = 81) reported to be treated for insomnia and 62 % were elderly (mean age 68, range 27-93). Fifty-two patients (64 %) were on long term treatment (>3 years) while for thirteen patients (16 %) duration of treatment was comprised between 1 and 3 years. Thirty-three patients were in favour of benzodiazepine-discontinuation but in all cases discontinuation was unsuccessful. CONCLUSION: Use of community pharmacy survey data allowed us to obtain information about incorrect management of insomnia and inappropriate benzodiazepines prescriptions. Stricter adherence to evidence-based guidelines is essential for a rational use of hypnotic and sedatives.

Reproducibility of liver iron concentration measured on a biopsy sample: a validation study in vivo.

Determination of liver iron concentration is essential to predict iron related tissue damage and to guide chelation therapy. To assess the reliability of a single biopsy iron concentration determination in representing the whole liver iron concentration, we conducted a prospective study performing two immediately successive liver biopsies from 61 noncirrhotic, iron overloaded thalassemia patients, directing the needle to different direction from the same skin cut. The correlation among sample biopsies was determined by both regression analysis and the Bland-Altman method. The results showed that overall correlation between the two samples was high (Pearson's coefficient of correlation r = 0.970, P < 0.0001; 95% CI 0.951-0.981; R(2) = 0.941). To evaluate if sample dimension had an impact on the analysis we analyzed separately biopsy couples were both sample gross weight were ≥1 mg dry weight (n = 16) from the others [one or both had a specimen gross weight <1 mg dry weight (n = 45)]. In the first case, correlation coefficient r was equal to 0.998 (P < 0.0001; 95% CI: 0.995-0.999; R(2) = 0.996) while in the latter was 0.960 (P < 0.0001; 95% CI: 0.928-0.977; R(2) = 0.921). In no instance second specimen prediction interval was outside the interval implying different prognostic and therapeutic decision if both liver samples gross weight were ≥1 mg dry weight. The Bland-Altman plot analysis showed the same trend observed using Pearson's correlation coefficient in the analyzed sample categories. Hepatic iron concentration determined in "good quality" biopsy specimen (i.e. sample gross weight ≥1 mg dry weight) is a reliable indicator of whole liver iron concentration.

Genetic variants regulating immune cell levels in health and disease.

The complex network of specialized cells and molecules in the immune system has evolved to defend against pathogens, but inadvertent immune system attacks on "self" result in autoimmune disease. Both genetic regulation of immune cell levels and their relationships with autoimmunity are largely undetermined. Here, we report genetic contributions to quantitative levels of 95 cell types encompassing 272 immune traits, in a cohort of 1,629 individuals from four clustered Sardinian villages. We first estimated trait heritability, showing that it can be substantial, accounting for up to 87% of the variance (mean 41%). Next, by assessing ∼8.2 million variants that we identified and confirmed in an extended set of 2,870 individuals, 23 independent variants at 13 loci associated with at least one trait. Notably, variants at three loci (HLA, IL2RA, and SH2B3/ATXN2) overlap with known autoimmune disease associations. These results connect specific cellular phenotypes to specific genetic variants, helping to explicate their involvement in disease.

A new fluorogenic peptide determines proteasome activity in single cells.

The ubiquitin-proteasome system plays a critical role in many diseases, making it an attractive biomarker and therapeutic target. However, the impact of results obtained in vitro using purified proteasome particles or whole cell extracts is limited by the lack of efficient methods to assess proteasome activity in living cells. We have engineered an internally quenched fluorogenic peptide with a proteasome-specific cleavage motif fused to TAT and linked to the fluorophores DABCYL and EDANS. This peptide penetrates cell membranes and is rapidly cleaved by the proteasomal chymotrypsin-like activity, generating a quantitative fluorescent reporter of in vivo proteasome activity as assessed by time-lapse or flow cytometry fluorescence analysis. This reporter is an innovative tool for monitoring proteasomal proteolytic activities in physiological and pathological conditions.

Formation of 2-substituted benzofuran fragment ions from 6-alkyl- and 6-aryldibenzo(d,f)(1,3)dioxepine derivatives under electron ionization-a useful precursor ion for isomeric differentiation.

Tandem mass spectrometry has been applied to differentiate three sets of o-, m- and p-methyl, -methoxy and -nitro-substituted-6-phenyl-dibenzo(d,f)(1,3)dioxepines. Collision-induced dissociation (CID) experiments have been carried out on 2-phenylbenzo[b]furan fragment ions, which originate from the decomposition of the molecular ions after their EI-induced isomerization to spirocyclic structures. With the exception of m- and p-methylphenylbenzo[b]furan isomers, which display identical CID mass spectra, the three isomeric methoxy- and nitrophenylbenzo[b]furan fragment ions display very characteristic CID behavior which allows unequivocal differentiation of the 6-phenyl-dibenzo(d,f)(1,3)dioxepine isomers. 6-(o-nitrophenyl)-dibenzo(d,f)(1,3)dioxepine isomer, does not form a 2-(o-nitrophenyl)benzo[b]furan ion and, therefore, it can be differentiated from the m- and p- isomers based on the mere EI mass spectra. Furthermore, it shows a characteristic ion most likely due to an ortho effect between the nitro group and the dioxepine ring. Multiple stage mass spectrometric techniques (MSn), labeled derivatives and reference compounds were used in order to gain additional information on the structures of product ion from the CID fragmentation.