Learning to Lead: An Exploration of Leadership Development in Obstetrics and Gynaecology.

Despite the demonstrated value of leadership in medicine, there is limited research on how physicians develop leadership skills. We administered a national survey (225 respondents) and conducted eight interviews of residents, fellows, and staff physicians in obstetrics and gynaecology to explore leadership skill development. Most (87%) positively rated the effectiveness of their leadership skills; however, the majority (98%) stated they would benefit from further training. Interview themes indicated that leadership skills can be taught, leadership training and roles should be intentional, training should be longitudinal, and barriers to training can be overcome with changes to the current model.

Low-fidelity simulation for management of postpartum haemorrhage in a Ghanaian teaching hospital.

We conducted a pre/post study of a post-partum hemorrhage (PPH) simulation exercise at Korle Bu Hospital, using a low-fidelity birthing simulator and questionnaires. We aimed to evaluate low-fidelity simulation as a feasible and effective method of improving resident knowledge and confidence in a low-resource setting. Knowledge and confidence in PPH management were measured before and after using 5-point Likert scales and multiple-choice questions. A feedback survey was administered. Descriptive statistics were calculated to summarize demographics, confidence, and knowledge, with frequencies, means and standard deviations reported. Statistical significance of the change in scores was assessed using paired t tests. Statistically significant improvements in knowledge and confidence in managing PPH were evident following the simulation exercise. All participants agreed the simulation was educational, relevant and realistic, and 94% felt it could be incorporated into their training.

Management of Group B Streptococcus-Positive Women With Preterm Premature Rupture of the Membranes: Still a Therapeutic Dilemma.

We discuss the management of GBS positive women with PPROM, an aspect of obstetrical management that remains controversial despite the publication of new randomized control trials in recent years. Clinical practice guidelines from several countries' national organizations are compared and contrasted, and areas of uncertainty are identified.

Retention of Vaginal Breech Delivery Skills Taught in Simulation.

OBJECTIVE: The optimal frequency of conducting simulation training for high-acuity, low-frequency events in obstetrics and gynaecology residency programs is unknown. This study evaluated retention over time of vaginal breech delivery skills taught in simulation, by comparing junior and senior residents. In addition, the residents' subjective comfort level to perform this skill clinically was assessed. METHODS: This prospective cohort study included 22 obstetrics and gynaecology residents in a Canadian residency training program. Digital recordings were completed for pre-training, immediate post-training, and delayed (10-26 weeks later) post-training intervals of a vaginal breech delivery simulation, with skill assessment by a blinded observer using a binary checklist. Residents also completed questionnaires to assess their subjective comfort level at each interval. RESULTS: Junior and senior residents had significant improvements in vaginal breech delivery skills from the pre-training assessment to both the immediate post-training assessment (junior, P <0.001; senior, P <0.001) and the delayed post-training assessment (P <0.001 and P = 0.001, respectively). There was a significant decline in skills between the immediate and delayed post-training sessions for junior and senior residents (P = 0.003 and P <0.001, respectively). Both junior and senior residents gained more comfort immediately after the training (P <0.001 and P <0.001, respectively), without a significant change between immediate post-training and delayed post-training comfort levels (P = 0.19 and P = 0.11, respectively). CONCLUSION: Residents retained vaginal breech delivery skills taught in simulation 10-26 weeks later, although a decline in skills occurred over this time period. Comfort level was positively affected and retained. These results will aid in determining the frequency of simulation teaching for high-acuity, low-frequency events in a residency simulation curriculum.

Developing a Canadian Curriculum for Simulation-Based Education in Obstetrics and Gynaecology: A Delphi Study.

OBJECTIVE: As obstetrics and gynaecology (Ob/Gyn) residency training programs move towards a competence-based approach to training and assessment, the development of a national standardized simulation curriculum is essential. The primary goal of this study was to define the fundamental content for the Canadian Obstetrics and Gynecology Simulation curriculum. METHODS: A modified Delphi technique was used to achieve consensus in three rounds by surveying residency program directors or their local simulation educator delegates in 16 accredited Canadian Ob/Gyn residency programs. A consensus rate of 80% was agreed upon. Survey results were collected over 11 months in 2016. RESULTS: Response rates for the Delphi were 50% for the first round, 81% for the second round, and 94% for the third round. The first survey resulted in 84 suggested topics. These were organized into four categories: obstetrics high acuity low frequency events, obstetrics common events, gynaecology high acuity low frequency events, and gynaecology common events. Using the modified Delphi method, consensus was reached on 6 scenarios. CONCLUSION: This study identified the content for a national simulation-based curriculum for Ob/Gyn residency training programs and is the first step in the development of this curriculum.

Does teaching of documentation of shoulder dystocia delivery through simulation result in improved documentation in real life?

OBJECTIVE: Documentation of deliveries complicated by shoulder dystocia is a valuable communication skill necessary for residents to attain during residency training. Our objective was to determine whether the teaching of documentation of shoulder dystocia in a simulation environment would translate to improved documentation of the event in an actual clinical situation. METHODS: We conducted a cohort study involving obstetrics and gynaecology residents in years 2 to 5 between November 2010 and December 2012. Each resident participated in a shoulder dystocia simulation teaching session and was asked to write a delivery note immediately afterwards. They were given feedback regarding their performance of the delivery and their documentation of the events. Following this, dictated records of shoulder dystocia deliveries immediately before and after the simulation session were identified through the Meditech system. An itemized checklist was used to assess the quality of residents' dictated documentation before and after the simulation session. RESULTS: All eligible residents (18) enrolled in the study, and 17 met the inclusion criteria. For 10 residents (59%) documentation of a delivery with shoulder dystocia was present before and after the simulation session, for five residents (29%) it was only present before the session, and for two residents (18%) it was only present after the session. When residents were assessed as a group, there were no differences in the proportion of residents recording items on the checklist before and after the simulation session (P > 0.05 for all). Similarly, analysis of the performance of the10 residents who had dictated documentation both before and after the session showed no differences in the number of elements recorded on dictations done before and after the simulation session (P > 0.05 for all). CONCLUSION: The teaching of shoulder dystocia documentation through simulation did not result in a measurable improvement in the quality of documentation of shoulder dystocia in actual clinical situations.

Objectif : La documentation des accouchements compliqués par une dystocie de l'épaule constitue une compétence communicationnelle précieuse que les résidents doivent chercher à maîtriser au cours de leur formation. Nous avions pour objectif de déterminer si l'enseignement de la documentation de la dystocie de l'épaule dans le cadre d'une simulation se traduisait en une amélioration de la documentation d'un tel événement dans le cadre d'une situation clinique réelle. Méthodes : Nous avons mené, entre novembre 2010 et décembre 2012, une étude de cohorte portant sur des résidents en obstétrique-gynécologie qui en étaient rendus à la 2e, 3e, 4e ou 5e année de leur formation. Chacun de ces résidents a participé à une séance de simulation de la dystocie de l'épaule; à cette occasion, nous leur avons demandé de rédiger une note sur l'accouchement immédiatement à la suite de la séance de simulation. Des commentaires leur ont été offerts quant à leur rendement au cours de l'accouchement et à leur documentation des événements. Par la suite, les dossiers dictés liés aux accouchements compliqués par une dystocie de l'épaule ayant eu lieu immédiatement avant et après la séance de simulation ont été récupérés dans le système Meditech. Une liste de vérification détaillée a été utilisée pour évaluer la qualité de la documentation dictée par les résidents avant et après la séance de simulation. Résultats : Tous les résidents admissibles (18) se sont inscrits à l'étude et 17 d'entre eux ont répondu aux critères d'inclusion. Dix résidents (59 %) avaient procédé à la documentation d'un accouchement compliqué par une dystocie de l'épaule avant et après la séance de simulation, cinq résidents (29 %) n'avaient procédé à une telle documentation qu'avant la séance et deux résidents (18 %) ne l'avaient fait qu'après la séance. Lorsque l'évaluation a porté sur les résidents en tant que groupe, aucune différence n'a été constatée pour ce qui est de la proportion des résidents consignant des articles tirés de la liste de vérification avant et après la séance de simulation (P > 0,05 pour tous). De façon semblable, l'analyse du rendement des 10 résidents qui avaient dicté une documentation tant avant qu'après la séance n'a révélé aucune différence pour ce qui est du nombre d'éléments consignés dans cette documentation avant et après la simulation (P > 0,05 pour tous). Conclusion : L'enseignement de la documentation de la dystocie de l'épaule au moyen de la simulation ne s'est pas traduit en une amélioration mesurable de la qualité de la documentation de la dystocie de l'épaule dans des situations cliniques réelles.

Permanent supportive housing: addressing homelessness and health disparities?

Permanent supportive housing (PSH) is an intervention to address long-term homelessness. Evidence has resulted in a shift in US policy toward using PSH rather than shelters and transitional housing. Despite recognizing that individuals transitioning from homelessness to PSH experience a high burden of disease and health disparities, public health research has not considered whether and how PSH improves physical health outcomes. Based on diverse areas of research, we argue that in addition to improved access to quality health care, social determinants of health (including housing itself, neighborhood characteristics, and built environment) affect health outcomes. We identify implications for practice and research, and conclude that federal and local efforts to end long-term homelessness can interact with concurrent efforts to build healthy communities.

Nearly complete rRNA genes from 371 Animalia: updated structure-based alignment and detailed phylogenetic analysis.

This study presents a manually constructed alignment of nearly complete rRNA genes from most animal clades (371 taxa from ~33 of the ~36 metazoan phyla), expanded from the 197 sequences in a previous study. This thorough, taxon-rich alignment, available at http://www.wsu.edu/~jmallatt/research/rRNAalignment.html and in the Dryad Repository (doi: http://dx.doi.org/10.5061/dryad.1v62kr3q), is based rigidly on the secondary structure of the SSU and LSU rRNA molecules, and is annotated in detail, including labeling of the erroneous sequences (contaminants). The alignment can be used for future studies of the molecular evolution of rRNA. Here, we use it to explore if the larger number of sequences produces an improved phylogenetic tree of animal relationships. Disappointingly, the resolution did not improve, neither when the standard maximum-likelihood method was used, nor with more sophisticated methods that partitioned the rRNA into paired and unpaired sites (stem, loop, bulge, junction), or accounted for the evolution of the paired sites. For example, no doublet model of paired-site substitutions (16-state, 16A and 16B, 7A-F, or 6A-C models) corrected the placement of any rogue taxa or increased resolution. The following findings are from the simplest, standard, ML analysis. The 371-taxon tree only imperfectly supported the bilaterian clades of Lophotrochozoa and Ecdysozoa, and this problem remained after 17 taxa with unstably positioned sequences were omitted from the analysis. The problem seems to stem from base-compositional heterogeneity across taxa and from an overrepresentation of highly divergent sequences among the newly added taxa (e.g., sequences from Cephalopoda, Rotifera, Acoela, and Myxozoa). The rogue taxa continue to concentrate in two locations in the rRNA tree: near the base of Arthropoda and of Bilateria. The approximately uncertain (AU) test refuted the monophyly of Mollusca and of Chordata, probably due to long-branch attraction of the highly divergent cephalopod and urochordate sequences out of those clades. Unlikely to be correct, these refutations show for the first time that rRNA phylogeny can support some 'wrong' clades. Along with its weaknesses, the rRNA tree has strengths: It recovers many clades that are supported by independent evidence (e.g., Metazoa, Bilateria, Hexapoda, Nonoculata, Ambulacraria, Syndermata, and Thecostraca with Malacostraca) and shows good resolution within certain groups (e.g., in Platyhelminthes, Insecta, Cnidaria). As another strength, the newly added rRNA sequences yielded the first rRNA-based support for Carnivora and Cetartiodactyla (dolphin+llama) in Mammalia, for basic subdivisions of Bryozoa ('Gymnolaemata+Stenolaemata' versus Phylactolaemata), and for Oligostraca (ostracods+branchiurans+pentastomids+mystacocarids). Future improvement could come from better sequence-evolution models that account for base-compositional heterogeneity, and from combining rRNA with protein-coding genes in phylogenetic reconstruction.

Two new marine hermit crabs allied with the Paguristes tortugae complex (Crustacea: Decapoda: Anomura) from the western Atlantic.

A recent molecular phylogenetic analysis that focused on selected species of western Atlantic Paguristes Dana, 1851, Areopaguristes Rahayu McLaughlin, 2010, and Pseudopaguristes McLaughlin, 2002 was somewhat inconclusive regarding relationships among those genera, but it revealed two new unrecognized species genetically related to members of the Paguristes tortugae complex. One of the new species is sister to A. hummi (Wass, 1955), which is readily separated from Wass taxon by significant differences in coloration. However, no definitive characters have been found for its identification on the basis of structural morphology. A second new species is genetically sister to P. tortugae Schmitt, 1933, even though it was regarded in earlier literature as no more than an ecomorphic variant expressing protective coloration related to habitat substrate color. In addition to its unique coloration, subtle distinctions are evident in structural morphology. Both species are formally named with accompanying morphological and color descriptions.

Molecular phylogenetic analysis of the Paguristes tortugae Schmitt, 1933 complex and selected other Paguroidea (Crustacea: Decapoda: Anomura).

Morphological characters, as presently applied to describe members of the Paguristes tortugae Schmitt, 1933 species complex, appear to be of limited value in inferring phylogenetic relationships within the genus, and may have similarly misinformed understanding of relationships between members of this complex and those presently assigned to the related genera Areopaguristes Rahayu McLaughlin, 2010 and Pseudopaguristes McLaughlin, 2002. Previously undocumented observations of similarities and differences in color patterns among populations additionally suggest genetic divergences within some species, or alternatively seem to support phylogenetic groupings of some species. In the present study, a Maximum Likelihood (ML) phylogenetic analysis was undertaken based on the H3, 12S mtDNA, and 16S mtDNA sequences of 148 individuals, primarily representatives of paguroid species from the western Atlantic. This molecular analysis supported a polyphyletic Diogenidae Ortmann, 1892, although incomplete taxonomic sampling among the genera of Diogenidae limits the utility of this finding for resolving family level relationships. Several hypotheses regarding the evolutionary relationships among hermit crab genera were refuted by the Kishino-Hasegawa (KH). Shimodaira-Hasegawa (SH) and Approximately Unbiased (AU) tree topology tests, among them the hypothesis that Areopaguristes is monophyletic. A lack of support for the monophyly of Areopaguristes calls into question the phylogenetic validity of gill number for the differentiation of Paguristes, Areopaguristes, and Pseudopaguristes. The study was inconclusive with regard to the relationships among these three genera, but previously unknown diversity within both Paguristes and Areopaguristes was demonstrated. Existence of an undescribed species confounded under the name Paguristes tortugae Schmitt, 1933 was supported by genetics, morphology, and coloration. A second undescribed species with remarkable similarity to Areopaguristes hummi Wass, 1955 was discovered based on genetics and coloration.

Subcapsular hepatic hematoma as a complication of severe preeclampsia: a case report.

BACKGROUND: Subcapsular hepatic hematoma is a rare and life-threatening complication of pregnancy. It is most commonly associated with severe preeclampsia and hemolytic anemia, elevated liver enzymes, and low platelets syndrome. Patients with subcapsular hepatic hematoma typically present with epigastric, right upper quadrant or shoulder pain, nausea and vomiting, and/or shortness of breath. Here we describe a patient with a classic pain presentation, a large unruptured hematoma, and an unusual postpartum course. CASE: A 40-year-old gravida 1 para 0 Caucasian woman presented at 39 + 6 weeks gestational age with a 3-day history of new onset pain in an otherwise uncomplicated pregnancy. She described the pain along her right torso as severe, shooting, and sharp, but at times pleuritic in nature. She was found to have new onset preeclampsia and hemolytic anemia, elevated liver enzymes, and low platelets syndrome. Induction of labor was initiated and eventually she delivered by cesarean section. Her pain persisted in the postpartum period and abdominal computed tomography scan revealed a 16 cm subcapsular hepatic hematoma. Despite the hematoma being thin walled, conservative management was recommended by the general surgeon. She then re-presented on postpartum day 15 with tachypnea, dyspnea, and pleuritic chest pain. Secondary to the subcapsular hepatic hematoma, she then developed an infected and loculated, large pleural effusion. This required video-assisted thoracoscopic surgery before her eventual discharge home on postpartum day 21. CONCLUSIONS: There should be high clinical suspicion of subcapsular hepatic hematoma in patients with persistent pain in the right upper quadrant of the abdomen. Urgent imaging to investigate for subcapsular hepatic hematoma is then indicated. Cesarean delivery without labor and treatment for severe preeclampsia should be undertaken if subcapsular hepatic hematoma is found. Conservative management and serial imaging are reasonable for the follow-up of a large, unruptured hematoma. Hepatic artery embolization should also be considered. Subcapsular hepatic hematoma may be complicated by infected pleural effusions and require video-assisted thoracoscopic surgery.

Nearly complete rRNA genes assembled from across the metazoan animals: effects of more taxa, a structure-based alignment, and paired-sites evolutionary models on phylogeny reconstruction.

This study (1) uses nearly complete rRNA-gene sequences from across Metazoa (197 taxa) to reconstruct animal phylogeny; (2) presents a highly annotated, manual alignment of these sequences with special reference to rRNA features including paired sites (http://purl.oclc.org/NET/rRNA/Metazoan_alignment) and (3) tests, after eliminating as few disruptive, rogue sequences as possible, if a likelihood framework can recover the main metazoan clades. We found that systematic elimination of approximately 6% of the sequences, including the divergent or unstably placed sequences of cephalopods, arrowworm, symphylan and pauropod myriapods, and of myzostomid and nemertodermatid worms, led to a tree that supported Ecdysozoa, Lophotrochozoa, Protostomia, and Bilateria. Deuterostomia, however, was never recovered, because the rRNA of urochordates goes (nonsignificantly) near the base of the Bilateria. Counterintuitively, when we modeled the evolution of the paired sites, phylogenetic resolution was not increased over traditional tree-building models that assume all sites in rRNA evolve independently. The rRNA genes of non-bilaterians contain a higher % AT than do those of most bilaterians. The rRNA genes of Acoela and Myzostomida were found to be secondarily shortened, AT-enriched, and highly modified, throwing some doubt on the location of these worms at the base of Bilateria in the rRNA tree--especially myzostomids, which other evidence suggests are annelids instead. Other findings are marsupial-with-placental mammals, arrowworms in Ecdysozoa (well supported here but contradicted by morphology), and Placozoa as sister to Cnidaria. Finally, despite the difficulties, the rRNA-gene trees are in strong concordance with trees derived from multiple protein-coding genes in supporting the new animal phylogeny.

Randomized trial of oral misoprostol before endometrial biopsy.

OBJECTIVE: To determine if the use of oral misoprostol in women undergoing endometrial biopsy reduces procedural discomfort. METHODS: Women undergoing endometrial biopsy were randomized to receive either 400 microg misoprostol or a vitamin B6 placebo orally 12 hours prior to the procedure, and were stratified based on menopausal status. The primary outcome was procedural discomfort on a visual analogue scale (0-10). Secondary outcomes included the need to dilate the cervix or use a tenaculum, and side effects. Subgroup analyses were planned for premenopausal and postmenopausal women separately. Sample size calculation was based on detecting a 50% reduction in pain, with alpha = 0.05 and beta = 0.10, in the premenopausal group. RESULTS: A total of 72 women (49 premenopausal and 23 postmenopausal) were enrolled; 35 received misoprostol (23 premenopausal and 12 postmenopausal) and 37 received placebo (26 premenopausal and 11 postmenopausal). There were no significant differences in procedural discomfort (misoprostol vs. placebo 5.8 +/- 2.9 vs. 5.5 +/- 3.2, P = 0.77; premenopausal women 4.9 +/- 3.3 vs. 5.1 +/- 3.1, P = 0.85; postmenopausal women 7.1 +/- 1.9 vs. 7.1 +/- 2.3, P = 0.99), need to dilate the cervix (6.1% vs. 5.6%, P = 0.93) or use a tenaculum (44.1% vs. 48.6%, P = 0.70). Significantly more women in the misoprostol group experienced nausea (31.4% vs. 2.7%, P = 0.001), diarrhea (20.0% vs. 2.7%, P = 0.02), abdominal pain (22.9% vs. 5.4%, P = 0.03), menstrual-like cramping (42.9% vs. 2.7%, P < 0.001) and vaginal bleeding (11.4% vs. 0%, P = 0.03). CONCLUSION: The use of 400 microg oral misoprostol 12 hours prior to endometrial biopsy did not reduce procedural discomfort and was associated with more side effects than use of placebo. This finding was noted in all women as well as among subgroups of premenopausal and postmenopausal women.

Two new species of the Phimochirus holthuisi complex from the Gulf of Mexico, supported by morphology, color, and genetics (Crustacea: Anomura: Paguridae).

Coloration, gene-sequence data (H3, 12s, 16s), and subtle features in morphology support the description of two new species, both formerly regarded to represent accepted variants of Phimochirus holthuisi s.l. While color in life consistently separates these species from P. holthuisi s.s. and from each other, morphological distinctions are subtle and less than absolute in small specimens, being based on ventral spine counts of walking leg dactyls and relative development of the superior crest on the major chela. Molecular phylogenetic analyses clearly support the separation of sister clades, representing two new species, from P. holthuisi s.s. as well as other congeners available for analysis. Both of the new species are presently known to occur widely throughout the northern Gulf of Mexico, though one occurs more commonly in the northeastern and southeastern Gulf, and may range as far south as Suriname. The other has been taken primarily in the northwestern Gulf, and is not known from outside Gulf waters. While both of the new species appear restricted to relatively deep subtidal waters of the continental shelf, Phimochirus holthuisi s.s. is instead more commonly found in shallow nearshore tropical waters on or near coral reefs. Previous literature reports of P. holthuisi usually represent, at least in part, one or both of these two new species.

Nanostructured fibers as a versatile photonic platform: radiative cooling and waveguiding through transverse Anderson localization.

Broadband high reflectance in nature is often the result of randomly, three-dimensionally structured materials. This study explores unique optical properties associated with one-dimensional nanostructures discovered in silk cocoon fibers of the comet moth, Argema mittrei. The fibers are populated with a high density of air voids randomly distributed across the fiber cross-section but are invariant along the fiber. These filamentary air voids strongly scatter light in the solar spectrum. A single silk fiber measuring ~50 µm thick can reflect 66% of incoming solar radiation, and this, together with the fibers' high emissivity of 0.88 in the mid-infrared range, allows the cocoon to act as an efficient radiative-cooling device. Drawing inspiration from these natural radiative-cooling fibers, biomimetic nanostructured fibers based on both regenerated silk fibroin and polyvinylidene difluoride are fabricated through wet spinning. Optical characterization shows that these fibers exhibit exceptional optical properties for radiative-cooling applications: nanostructured regenerated silk fibers provide a solar reflectivity of 0.73 and a thermal emissivity of 0.90, and nanostructured polyvinylidene difluoride fibers provide a solar reflectivity of 0.93 and a thermal emissivity of 0.91. The filamentary air voids lead to highly directional scattering, giving the fibers a highly reflective sheen, but more interestingly, they enable guided optical modes to propagate along the fibers through transverse Anderson localization. This discovery opens up the possibility of using wild silkmoth fibers as a biocompatible and bioresorbable material for optical signal and image transport.

An analysis of the definitions and elements of recovery: a review of the literature.

As mental health recovery gains traction, many people have put forward varying definitions. Few attempts have been made to create a dimensional analysis of the recovery literature that assesses the growing consensus about what recovery is or what its definition should entail. This paper incorporates an ecological framework to take the individual's life context into account while emphasizing both the reestablishment of one's mental health (i.e., first order change) and the mitigation of the oppressive nature of barriers imposed by the greater community (i.e., second order change) so that people may experience social integration and community inclusion.

Combination antipsychotics: pros, cons, and questions.

In prescription surveys, use of combination antipsychotics is common and is increasing, despite little supporting evidence. This article highlights potential problems with using combination antipsychotics, discusses paths to their maintenance use, and reviews the efficacy evidence. Paths to maintenance antipsychotic combinations include (1) failure or patient refusal of all reasonable monotherapies, (2) indefinite continuation of combinations initially intended to be brief, (3) trials of combinations in preference to reasonable monotherapy trials, and (4) addition of a second antipsychotic to counteract a problem (safety, tolerability, or adherence) arising during successful monotherapy. Virtually all of the evidence on combination antipsychotics is on augmentation of clozapine, with only one randomized controlled trial. Research on combination antipsychotics is sorely needed. Designing clinical trials is made difficult by the very large numbers of possible combinations and doses. It may be feasible to analyze existing data bases to identify combinations that appear particularly promising to investigate.

Comparative architecture of silks, fibrous proteins and their encoding genes in insects and spiders.

The known silk fibroins and fibrous glues are thought to be encoded by members of the same gene family. All silk fibroins sequenced to date contain regions of long-range order (crystalline regions) and/or short-range order (non-crystalline regions). All of the sequenced fibroin silks (Flag or silk from flagelliform gland in spiders; Fhc or heavy chain fibroin silks produced by Lepidoptera larvae) are made up of hierarchically organized, repetitive arrays of amino acids. Fhc fibroin genes are characterized by a similar molecular genetic architecture of two exons and one intron, but the organization and size of these units differs. The Flag, Ser (sericin gene) and BR (Balbiani ring genes; both fibrous proteins) genes are made up of multiple exons and introns. Sequences coding for crystalline and non-crystalline protein domains are integrated in the repetitive regions of Fhc and MA exons, but not in the protein glues Ser1 and BR-1. Genetic 'hot-spots' promote recombination errors in Fhc, MA, and Flag. Codon bias, structural constraint, point mutations, and shortened coding arrays may be alternative means of stabilizing precursor mRNA transcripts. Differential regulation of gene expression and selective splicing of the mRNA transcript may allow rapid adaptation of silk functional properties to different physical environments.