Trajectories of suicidal ideation during rTMS for treatment-resistant depression

BACKGROUND

rTMS is a safe and effective intervention for treatment-resistant depression (TRD). However, there is limited data on its specific impact on suicidal ideation (SI), and the trajectory of SI over the treatment course.

OBJECTIVE

This open-label clinical trial investigated SI outcomes and trajectories in patients with TRD receiving low-frequency rTMS (LFR) to the right dorsolateral prefrontal cortex (DLPFC; N = 55).

METHODS

A latent class mixed-effect model was used to identify response trajectories for SI as well as core mood symptoms. Logistic regression analyses investigated risk factors associated with identified trajectories.

RESULTS

For each symptom domain, we identified two distinct trajectories during LFR, one tracking improvement (SI: n = 35, 60 %; mood: n = 29, 53 %) and the other tracking no improvement (SI: n = 20, 40 %; mood: n = 26, 47 %). Male sex, higher baseline anxiety, and higher baseline SI were risk factors for no improvement of SI; while higher baseline anxiety and benzodiazepine use were risk factors for no improvement of mood. Mediation analyses showed that anxiety was a risk factor for no improvement of SI and mood independent of benzodiazepine treatment.

CONCLUSIONS

This is the first study to investigate trajectories of response to LFR to the right DLPFC. SI and mood improved with LFR in most patients but the severity of anxiety symptoms was a factor of poor prognosis for both. Nuanced characterization of SI response to rTMS may lead to critical insights for individualized targeting strategies.

Evidence of factors influencing delays in the diagnosis and treatment of bipolar disorder in adolescents and young adults. Protocol for a systematic scoping review

BACKGROUND

Bipolar Disorder (BD) is a complex psychiatric condition that typically manifests during late adolescence and early adulthood. Over the past two decades, international studies have reported that BD often goes unrecognized and untreated for several years, which can lead to negative clinical and functional outcomes. However, the components of delay in the diagnosis and treatment of BD and various factors influencing those components have not been systematically explored.

OBJECTIVES

The scoping review described in this protocol aims to map the existing literature on potential factors that influence delays in the treatment of BD in adolescents and young adults, in order to identify the knowledge gaps and future research and policy priorities.

METHODS

This protocol for a systematic scoping review will be reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline (PRISMA-ScR). We will search the electronic databases of MEDLINE (OVID), EMBASE, PsycINFO and CINAHL for peer-reviewed primary research articles published in academic journals. Grey literature will not be explored due to resource limitations. A conceptual framework based on the Model of Pathways to Treatment by Scott and colleagues was used as a foundation for our search and extraction strategy to ensure all components of delay and potential factors influencing each component are explored. Two independent reviewers will screen the references retrieved by the literature search and select relevant studies based on our inclusion criteria. The data from included studies will be synthesized into a narrative summary, and implications for future research, practice and policy will be discussed.

DISCUSSION

To the best of our knowledge, this will be the first scoping review to explore the potential factors that influence delays in the treatment of BD in adolescents and young adults. We intend to disseminate the review results through academic conferences and publication in a peer-reviewed journal.

Caring for youth with co-occurring substance use and severe psychiatric disorders: diagnostic challenges and clinical implications

Appropriate interventions for psychiatric conditions that commonly emerge during adolescence and early adulthood play a crucial role in modifying both acute risks as well as long-term outcomes. Substance use disorder is a common comorbidity during the early stages of mood and psychotic disorders that further heightens acute risks and is considered a negative prognostic factor. New presentations of mood and psychotic symptoms with co-occurring substance use are inherently challenging to formulate due to the uncertainty surrounding the relative impact of multiple intrinsic and extrinsic factors. Given such uncertainty, it is natural for clinicians to rely on heuristics to guide assessment and management. These heuristics however may bring about premature diagnostic closure by favouring the primacy of substance use, which in turn can result in a missed window of opportunity for a timely and appropriate intervention. We caution clinicians against over-attributing early symptoms of mood and psychotic disorders to substances use alone.

Precocious White Matter Inflammation and Behavioural Inflexibility Precede Learning and Memory Impairment in the TgAPP21 Rat Model of Alzheimer Disease

Neuroinflammation and behavioural inflexibility are both common in late adulthood but far more profound in Alzheimer disease (AD). To investigate the relationship between ageing, AD, neuroinflammation, and behavioural flexibility, male wild-type Fischer 344 (Wt) and the transgenic APP21 (TgAPP21) rats were aged to 4, 8, 13, and 22 months and evaluated for neuroinflammation and cognitive impairment. TgAPP21 rats overexpress a pathogenic variant of the human amyloid precursor protein (hAPP; Swedish and Indiana mutations) but do not spontaneously develop overt pathology related to AD. In both genotypes, learning and memory were similarly impaired in older rats. However, at 8 months of age, TgAPP21 rats demonstrated behavioural inflexibility in set shifting, reversal, and the Morris water maze, while Wt rats showed inflexibility at 13 and 22 months of age. This early inflexibility in TgAPP21 rats was accompanied by a precocious increase in microglia activation within the corpus callosum; 8- and 13-month-old TgAPP21 rats had similar levels of microglia activation as 13- and 22-month-old Wt rats, respectively. However, while neuroinflammation within the white matter continued to progress with age, behavioural inflexibility peaked in 8-month-old TgAPP21 rats; in older TgAPP21 rats, memory and learning impairments masked inflexibility. These findings suggest that the behavioural inflexibility and white matter inflammation seen in normal ageing are accelerated in AD and may precede impairments of learning and memory.

Pay for Performance and Treatment Outcome in Agonist Treatment for Opioid Use Disorder

BACKGROUND AND OBJECTIVES

Pay for performance (P4P) models have become more popular in reimbursement for medical services, including treatment for substance use disorders. However, studies have not examined whether P4P has an impact on treatment outcome in the individual in opioid agonist treatment (OAT). Thus, the present study was conducted at the individual level, rather than the programmatic level, to determine whether meeting the P4P early engagement criteria (four services in the initial 14 days of treatment and/or eight services within the initial 30 days of treatment) resulted in reduced opioid, benzodiazepine, and cocaine use.

METHODS

We performed a retrospective study of 63 patients enrolled in OAT for opioid use disorder. χ² analyses were conducted crossing P4P early engagement criteria status and urine drug screen (UDS) results for opioid, cocaine, and/or benzodiazepine use at 6 and 12 months postadmission. Methadone dosage and treatment retention were also considered. The odds ratio was used to determine the directionality of significant results.

RESULTS

Significant relationships were revealed between patients meeting 30-day P4P early engagement criteria and opioid negative UDS, and with retention in treatment at 6 and 12 months. Methadone dosage was significant at a 6-month follow-up.

DISCUSSION AND CONCLUSIONS

Since significant associations between opioid use and P4P as well as opioid use and methadone dose were revealed, findings partially supported hypothesis.

SCIENTIFIC SIGNIFICANCE

P4P and methadone dosage may have some benefit to individuals in OAT in attaining short-term abstinence from opioids. P4P may be less useful in helping individuals achieve abstinence from other substances of abuse. (Am J Addict 2020;00:00-00).

TSPO PET detects acute neuroinflammation but not diffuse chronically activated MHCII microglia in the rat

Background

Accurate and sensitive imaging biomarkers are required to study the progression of white matter (WM) inflammation in neurodegenerative diseases. Radioligands targeting the translocator protein (TSPO) are considered sensitive indicators of neuroinflammation, but it is not clear how well the expression of TSPO coincides with major histocompatibility complex class II (MHCII) molecules in WM. This study aimed to test the ability of TSPO to detect activated WM microglia that are immunohistochemically positive for MHCII in rat models of prodromal Alzheimer’s disease and acute subcortical stroke.

Methods

Fischer 344 wild-type (n = 12) and TgAPP21 (n = 11) rats were imaged with [¹⁸F]FEPPA PET and MRI to investigate TSPO tracer uptake in the corpus callosum, a WM region known to have high levels of MHCII activated microglia in TgAPP21 rats. Wild-type rats subsequently received an endothelin-1 (ET1) subcortical stroke and were imaged at days 7 and 28 post-stroke before immunohistochemistry of TSPO, GFAP, iNOS, and the MHCII rat antigen, OX6.

Results

[¹⁸F]FEPPA PET was not significantly affected by genotype in WM and only detected increases near the ET1 infarct (P = 0.033, infarct/cerebellum uptake ratio: baseline = 0.94 ± 0.16; day 7 = 2.10 ± 0.78; day 28 = 1.77 ± 0.35). Immunohistochemistry confirmed that only the infarct (TSPO cells/mm²: day 7 = 555 ± 181; day 28 = 307 ± 153) and WM that is proximal to the infarct had TSPO expression (TSPO cells/mm²: day 7 = 113 ± 93; day 28 = 5 ± 7). TSPO and iNOS were not able to detect the chronic WM microglial activation that was detected with MHCII in the contralateral corpus callosum (day 28 OX6% area: saline = 0.62 ± 0.38; stroke = 4.30 ± 2.83; P = .029).

Conclusion

TSPO was only expressed in the stroke-induced insult and proximal tissue and therefore was unable to detect remote and non-insult-related chronically activated microglia overexpressing MHCII in WM. This suggests that research in neuroinflammation, particularly in the WM, would benefit from MHCII-sensitive radiotracers.

Challenges and opportunities for future Canadian physician-scientists: Perspectives of four experts

In this series of interviews, the Clinical and Investigative Medicine editorial team gathered expert opinions on the future of physician-scientist training and career prospects in Canada. This was inspired by recent publications that voiced concerns over the diminishing support for the physician-scientist in Canada and the United States. For this editorial, the term physician-scientist was intentionally broad and inclusive; referring to individuals who identify both clinical work and biomedical or healthcare research as major components of their career. The following leaders in medical research or research funding shared their perspectives: Roderick R. McInnes; Michel G. Bergeron; Thomas J. Marrie; and Bev J. Holmes.

Hypertension and Pathogenic hAPP Independently Induce White Matter Astrocytosis and Cognitive Impairment in the Rat

Hypertension is recognized as a risk factor for Alzheimer disease, but the causal link remains undetermined. Although astrocytes and microglia play an important role in maintaining the neurovascular unit, astrocytes and microglia have been understudied in comorbid models of hypertension and Alzheimer disease. In this study, male transgenic Fischer 344 rats (TgAPP21) overexpressing a pathogenic human amyloid precursor protein received 8 weeks of Angiotensin II infusion to increase blood pressure, and the rats were evaluated for astrocytosis, microgliosis, and cognitive function. A linear relationship between astrocytosis and blood pressure was observed in the corpus callosum and cingulum of wildtype rats, with hypertensive wildtype rats matching the elevated baseline astrocytosis seen in normotensive transgenic rats. In contrast, hypertensive transgenic rats did not demonstrate a further increase of astrocytosis, suggesting a deficient response. Angiotensin II infusion did not affect activation of microglia, which were elevated in the white matter and hippocampus of transgenic rats. Angiotensin II infusion did impair both wildtype and transgenic rats’ executive functions in the Morris Water Maze. These results present important implications for the interaction between hypertension and pathogenic human amyloid precursor protein expression, as Angiotensin II infusion produced cognitive impairments in both genotypes, but transgenic rats were additionally impaired in developing a normal astrocytic response to elevated blood pressure.

Fourth Annual Clinician Scientist Trainee Symposium at the Schulich School of Medicine and Dentistry

The Annual Clinician Scientist Trainee Symposium (CSTS) gathers the local medical research community at the Schulich School of Medicine and Dentistry, including research trainees at the medical student, resident and fellow levels. Trainees showcase their current and upcoming work, and leaders in the community impart their perspectives on the importance and future of research in medicine. At the 4th Annual CSTS, perseverance and cautious optimism emerged as the characteristics that trainees should foster through their future careers as clinician scientists. This was echoed by the challenges and encouraging findings presented by trainees, who conducted their work as part of research projects within the MD, MD/PhD and clinical investigator programs. The four oral presentations and 10 three-minute thesis presentations covered the full breadth of medical disciplines across the spectrum of translational medicine, from fundamental sciences through knowledge translation. The CSTS concluded with the keynote presentation by Michael Strong, current president of the Canadian Institutes of Health Research, who gave a glimpse into his decades-long path of overcoming and overturning dogmatic views in the world of amyotrophic lateral sclerosis research, demonstrating how roadblocks in research can become an impulse for stronger science.

Newsletter Fall 2019: Clinician Investigator Trainee Association of Canada (CITAC)

A message from Elina Cook (President): Demystifying and promoting the MD-PhD/MSc world—our progress Clinician Investigator Trainee Association of Canada (CITAC) seeks to promote, support and advocate for trainees whose goal is to become physician/ clinician/surgeon investigators. These include trainees of MD-PhD/MSc programs and Clinician Investigator Programs (CIP), who are preparing themselves to succeed in the overlapping world of medicine and research. Thanks to the wealth of talent, skill and motivation of the CITAC leadership this year, we are delivering new opportunities to these trainees in a number of ways: 1) developing international partnerships and initiatives; 2) revitalizing the Annual General Meeting (AGM); 3) advocating for clinician/physician/surgeon-scientist trainee support among influencers and policy makers; and 4) collecting data on the academic “health” of our training programs and trainees across Canada.

Scientific Overview on CSCI-CITAC Annual General Meeting and 2018 Young Investigators’ Forum

The 2018 Annual General Meeting (AGM) and Young Investigators’ Forum (YIF) of the Canadian Society of Clinician Investigators (CSCI) and Clinician Investigator Trainee Association of Canada/Association des Cliniciens-Chercheurs en Formation du Canada (CITAC/ACCFC) was held in Toronto, Ontario on November 19–20, 2018, in conjunction with the University of Toronto Clinician Investigator Program Research Day. The theme for the meeting was “Prepare for Success—Things to Master Now for Clinician Scientists in Training”; with lectures and workshops that were designed to provide knowledge and hands-on skills to navigate life as a clinician investigator. The opening remarks were by Jason Berman (President of CSCI), Josh Abraham (President of CITAC/ACCFC) and Nicola Jones (University of Toronto Clinician Investigator Symposium Chair). The keynote speakers were Dr. Ruth Ann Marrie (University of Manitoba), who received the Distinguished Scientist Award, Dr. Davinder Jassal (University of Manitoba), who received the CSCI-RCPSC Henry Friesen Award, and Dr. Aleixo Muise (University of Toronto), who received the Joe Doupe Young Investigator Award. Dr. Minna Woo (University of Toronto), Canada Research Chair in Diabetes Signal Transduction, delivered the keynote lecture “From Onion Cells to Single Cell Seq—A Constant Change in Lenses: A perspective of an evolving clinician scientist”. The workshops, focusing on career development for clinician-scientists, were hosted by Drs. Robert Chen, Stephen Juvet, Lorraine Kalia, Phyllis Billia, Neil Goldenberg, Nicola Jones, Srdjanaa Filipovic, Jason Berman, Josh Abraham, Melanie Szweras, Joseph Ferenbok and Uri Tabori. The AGM also included presentations from clinician investigator trainees from across the country, and these abstracts are summarized in this review. Over 80 abstracts were showcased at this year’s meeting during the poster session, with six outstanding abstracts selected for oral presentations during the President’s Forum.

Impaired behavioural flexibility related to white matter microgliosis in the TgAPP21 rat model of Alzheimer disease

Executive dysfunction and white matter inflammation continue to be relatively understudied in rodent models of Alzheimer's disease (AD). Behavioural inflexibility is an important component of executive dysfunction that can be further categorized as perseverative or regressive, which respectively specify whether maladaptive persistence occurs early or late during a behavioural change. Previous studies of the TgAPP21 rat model of AD (expressing pathogenic hAPP) suggested a potentially spontaneous increase of regressive behavioral inflexibility. In this study, 7-8-month-old male TgAPP21 rats were tested for behavioral flexibility, learning, and memory using an operant conditioning chamber and the Morris Water Maze (MWM). TgAPP21 rats demonstrated a regressive behavioral inflexibility during set shifting in an operant conditioning chamber (regressive errors η² = 0.32 and number of errors after criterion η² = 0.33). Regressive behavior was also demonstrated in the MWM probe test, wherein TgAPP21 rats significantly increased their swim time in the target quadrant during the last third of the probe test (43% vs 33% in the first 2 thirds of the probe test or the Wt rats' 29%-32%); this behavioral phenotype has not been previously described in the MWM. TgAPP21 demonstrated further impairment of behavioural inflexibility as they committed a greater number of reversal errors in the operant conditioning chamber (η² = 0.30). Diffuse microglia activation was increased in the white matter tracts of TgAPP21 (corpus callosum, cingulum, and internal capsule; η² = 0.59-0.62), which was found to correlate with the number of reversal errors in the operant conditioning chamber (R² = 0.42). As TgAPP21 rats do not spontaneously develop amyloid plaques but have been shown in previous studies to be vulnerable to the development of plaques, these rats demonstrate an important onset of cognitive change and inflammation in the pre-plaque phase of AD. TgAPP21 rats are also an instrumental model for studying the role and mechanism of white matter microglial activation in executive functioning. This is pertinent to clinical research of prodromal AD which has suggested that white matter inflammation may underlie impairment of executive functions such as behavioral flexibility.

Scientific overview on CSCI-CITAC Annual General Meeting and 2017 Young Investigators' Forum

The 2017 Annual General Meeting of the Canadian Society of Clinician Investigators (CSCI) and Clinician Investigator Trainee Association of Canada/Association des Cliniciens-Chercheurs en Formation du Canada (CITAC/ACCFC) was a national Annual General Meeting (AGM) held in Toronto, Ontario November 20-22, 2017, in conjunction with the University of Toronto Clinician Investigator Program Research Day. The theme for this year's meeting was "Roll up your sleeves-How to manage your physician scientist career", emphasizing lectures and workshops that were designed to provide tools for being proactive and successful in career planning. The keynote speakers were Dr. Rod McInnes (McGill University and Canadian Institutes of Health Research Acting President), who was the Distinguished Scientist Award recipient, Dr. David Goltzman (McGill University), who was the 2017 Henry Friesen Award recipient, Dr. Gillian Hawker (University of Toronto), Dr. Mike Sapieha (Université de Montréal), who was the 2017 Joe Doupe Award recipient, and Dr. Alex MacKenzie (Children's Hospital of Eastern Ontario Research Institute, University of Ottawa). The workshops, focusing on career development for clinician scientists, were hosted by Dr. Lisa Robinson, Dr. Nicola Jones, Kevin Vuong, Fran Brunelle, Dr. Jason Berman and Dr. Alan Underhill. Further to this, the Young Investigators' Forum encompasses presentations from scientist-clinician trainees from across the country. All scientific abstracts are summarized in this review. There were over 100 abstracts showcased at this year's meeting during the highlighted poster sessions, with six outstanding abstracts selected for oral presentations during the President's Forum.

Behavioural inflexibility in a comorbid rat model of striatal ischemic injury and mutant hAPP overexpression

Alzheimer disease (AD) and stroke coexist and interact; yet how they interact is not sufficiently understood. Both AD and basal ganglia stroke can impair behavioural flexibility, which can be reliably modeled in rats using an established operant based set-shifting test. Transgenic Fischer 344-APP21 rats (TgF344) overexpress pathogenic human amyloid precursor protein (hAPP) but do not spontaneously develop overt pathology, hence TgF344 rats can be used to model the effect of vascular injury in the prodromal stages of Alzheimer disease. We demonstrate that the injection of endothelin-1 (ET1) into the dorsal striatum of TgF344 rats (Tg-ET1) produced an exacerbation of behavioural inflexibility with a behavioural phenotype that was distinct from saline-injected wildtype & TgF344 rats as well as ET1-injected wildtype rats (Wt-ET1). In addition to profiling the types of errors made, interpolative modeling using logistic exposure-response regression provided an informative analysis of the timing and efficiency of behavioural flexibility. During set-shifting, Tg-ET1 committed fewer perseverative errors than Wt-ET1. However, Tg-ET1 committed significantly more regressive errors and had a less efficient strategy change than all other groups. Thus, behavioural flexibility was more vulnerable to striatal ischemic injury in TgF344 rats.

An exploratory comparative analysis of tyrosine kinase inhibitors or docetaxel in second-line treatment of EGFR wild-type non-small-cell lung cancer: a retrospective real-world practice review at a single tertiary care centre

BACKGROUND

Treatment for advanced non-small-cell lung cancer (nsclc), especially in patients with wild-type EGFR, remains limited. Recently, erlotinib, a tyrosine kinase inhibitor (tki) targeting EGFR mutation, was approved as second-line treatment in EGFR wild-type nsclc. Despite evidence of better overall survival (os) with chemotherapy than with tki in second-line treatment, data on the use of tki in the real-life clinical setting remain limited. The present practice review of tki use for second- and third-line treatment in EGFR wild-type nsclc also compares clinical outcomes for tki and single-agent docetaxel as second-line treatment.

METHODS

Our retrospective cohort study included patients with EGFR wild-type nsclc treated at the Jewish General Hospital (Montreal, QC) between 2003 and 2013. Patients received a tki (erlotinib or gefitinib) in the second and third line or docetaxel in the second line. For each group, we determined os, disease control rate, progression-free survival (pfs), and event-free survival (efs).

RESULTS

The tki group included 145 patients, with 92 receiving second-line treatment. In the control group, 53 patients received docetaxel as second-line therapy. In the tki group, os was 6.0 months; pfs, 2.7 months; and efs, 3.0 months. Comparing second-line treatments, os was 5.3 and 5.0 months respectively (p = 0.88), pfs was 2.5 and 1.8 months respectively (p = 0.041), and efs was 3.0 and 1.7 months respectively (p = 0.009).

CONCLUSIONS

In our study cohort, second-line therapy for EGFR wild-type nsclc with tki (compared with docetaxel) was associated with statistically better pfs and efs and noninferior os. Those findings raise the question of whether efs should also be considered when choosing second-line treatment in this patient population.

[Are we controlling the sedation in ICU? A multicenter study results]

The aim of this study is to evaluate the issues of sedation and analgesia in all-purpose ICUs in Russia. To obtain that, a single-day observational survey was performed in 55 ICUs of Ural and Siberia regions. This work enabled to describe the targets, instruments of control and patterns of sedative and analgetics and sedatives prescription, as well as to make conclusions about issues in this area and possibilities of creation and necessity of analgesia and sedation standards. The study has shown a decent percentage of use of standardized scales evaluating pain in ICU and predominance of effectivae drugs and analgesia patterns, which leads to "formalization" of analgesia and decrease of it's effectiveness. Sedation indications do not satisfy the modern concept, sedation level evaluation scores are used only in 13%, schemes and drugs are traditional. The results of this study may serve as a reason for discussion of necessity of introducing of sedative and analgetic therapy in ICU standarts.

Two novel exonic point mutations in HEXA identified in a juvenile Tay-Sachs patient: role of alternative splicing and nonsense-mediated mRNA decay

We have identified three mutations in the beta-hexoseaminidase A (HEXA) gene in a juvenile Tay-Sachs disease (TSD) patient, which exhibited a reduced level of HEXA mRNA. Two mutations are novel, c.814G>A (p.Gly272Arg) and c.1305C>T (p.=), located in exon 8 and in exon 11, respectively. The third mutation, c.1195A>G (p.Asn399Asp) in exon 11, has been previously characterized as a common polymorphism in African-Americans. Hex A activity measured in TSD Glial cells, transfected with HEXA cDNA constructs bearing these mutations, was unaltered from the activity level measured in normal HEXA cDNA. Analysis of RT-PCR products revealed three aberrant transcripts in the patient, one where exon 8 was absent, one where exon 11 was absent and a third lacking both exons 10 and 11. All three novel transcripts contain frameshifts resulting in premature termination codons (PTCs). Transfection of mini-gene constructs carrying the c.814G>A and c.1305C>T mutations proved that the two mutations result in exon skipping. mRNAs that harbor a PTC are detected and degraded by the nonsense-mediated mRNA decay (NMD) pathway to prevent synthesis of abnormal proteins. However, although NMD is functional in the patient's fibroblasts, aberrant transcripts are still present. We suggest that the level of correctly spliced transcripts as well as the efficiency in which NMD degrade the PTC-containing transcripts, apparently plays an important role in the phenotype severity of the unique patient and thus should be considered as a potential target for drug therapy.

Radon exhalation of cementitious materials made with coal fly ash: Part 2--testing hardened cement-fly ash pastes

Increased interest in measuring radionuclides and radon concentrations in fly ash (FA), cement and other components of building products is due to the concern about health hazards of naturally occurring radioactive materials (NORM). The paper focuses on studying the influence of FA on radon exhalation rate (radon flux) from cementitious materials. In the previous part of the paper the state of the art was presented, and the experiments for testing raw materials, Portland cement and coal fly ash, were described. Since the cement and FA have the most critical role in the radon release process relative to other concrete constituents (sand and gravel), and their contribution is dominant in the overall radium content of concrete, tests were carried out on cement paste specimens with different FA contents, 0-60% by weight of the binder (cement+FA). It is found that the dosage of FA in cement paste has a limited influence on radon exhalation rate, if the hardened material is relatively dense. The radon flux of cement-FA pastes is lower than that of pure cement paste: it is about approximately 3 mBq m(-2) s(-1) for cement-FA pastes with FA content as high as 960 kg m(-3).

Double-layer closure of uterine incision with visceral and parietal peritoneal closure: are they obligatory steps of routine cesarean sections?

The objective of this study was to examine the feasibility of a modified technique of cesarean section in which the uterine incision is sutured in one layer and the visceral and parietal peritoneum are left open. Two hundred patients undergoing a low segment cesarean section were prospectively randomized (according to the patients' identity numbers) into two groups. The first group had standard cesarean section including a continuous double layer closure of uterine incision in addition to closure of visceral and parietal peritoneum. The second group underwent the modified procedure as described above. The modified technique compared to the standard technique, resulted in shorter operative time (32 +/- 11 versus 44 +/- 16 min, P < 0.0001) and a reduced need for postoperative sedation (P < 0.004). The operative procedure was shown, by multiple regression analysis, to be the significant factor that determined its length. Postoperative morbidity was similar in the two groups. The modified technique of cesarean section reduces operative time and postoperative narcotic requirement, and has no adverse affect on postoperative recovery. A double-layer closure of low uterine incision, re-approximation of bladder flap, and closure of parietal peritoneum, as in the standard technique, do not seem to be essential steps of cesarean section. Larger studies are needed to ensure the safety of one-layer uterine closure in future deliveries.

Clavicular fracture of the neonate: can it be predicted before birth?

A retrospective study of 3873 cephalic vaginal births was undertaken to evaluate which factors are associated with clavicular fractures and thereby assess their clinical relevance in antepartum prediction. Fifty-two neonates with a fractured clavicle were identified, an incidence of 1.3%. Neonates with fractures were compared to a control group without fractures. The two groups were matched for age, parity, and mode of delivery. The neonates with fractures were found to be significantly heavier than controls, with mean birthweights of 3.7 kg and 3.2 kg, respectively (p = 0.000). Significantly more newborns in the fracture group weighed more than 4 kg (p = 0.02). A similar trend was noted when birthweights of previous pregnancies were compared (p = 0.03). Fracture cases had a greater incidence of low 1-minute Apgar scores (p = 0.02), and a higher proportion of births following abnormal progress of labor (19% of fracture group and 2.9% of controls; p = 0.001). Despite these statistically significant differences between the groups, it is not possible to predict most cases of fracture before birth, since the majority of fractures occur in cases not identified by any of the studied parameters.

Continuous ambulatory peritoneal dialysis as the primary approach in the management of severe renal insufficiency in pregnancy

Pregnancy is an unusual event in patients with chronic renal failure undergoing dialysis. The outcome in these cases is usually poor. We report a pregnancy complicated by severe renal insufficiency that was managed successfully by continuous ambulatory peritoneal dialysis. Dialysis was initiated at 24 weeks' gestation. At 34 weeks, premature labor associated with peritonitis resulted in the spontaneous delivery of a healthy male infant weighing 2400 g. The use of continuous ambulatory peritoneal dialysis during pregnancy offers theoretical advantages compared with hemodialysis. Our case, added to the available limited experience with this new modality, suggests that it may be an appropriate approach in women developing renal disease for the first time during pregnancy.

Two rare complications of simultaneously occurring placenta praevia and placenta percreta

Simultaneously occurring placenta praevia and placenta percreta is a well known yet rare obstetric complication. Cases in which invasion of chorionic villi lead to asymptomatic perforation of the uterus or bladder, rarely occur. This paper describes two such cases.