Targeted INO80 enhances subnuclear chromatin movement and ectopic homologous recombination.

Chromatin in the interphase nucleus moves in a constrained random walk. Despite extensive study, the molecular causes of such movement and its impact on DNA-based reactions are unclear. Using high-precision live fluorescence microscopy in budding yeast, we quantified the movement of tagged chromosomal loci to which transcriptional activators or nucleosome remodeling complexes were targeted. We found that local binding of the transcriptional activator VP16, but not of the Gal4 acidic domain, enhances chromatin mobility. The increase in movement did not correlate strictly with RNA polymerase II (PolII) elongation, but could be phenocopied by targeting the INO80 remodeler to the locus. Enhanced chromatin mobility required Ino80's ATPase activity. Consistently, the INO80-dependent remodeling of nucleosomes upon transcriptional activation of the endogenous PHO5 promoter enhanced chromatin movement locally. Finally, increased mobility at a double-strand break was also shown to depend in part on the INO80 complex. This correlated with increased rates of spontaneous gene conversion. We propose that local chromatin remodeling and nucleosome eviction increase large-scale chromatin movements by enhancing the flexibility of the chromatin fiber.

Reactivating head regrowth in a regeneration-deficient planarian species.

Species capable of regenerating lost body parts occur throughout the animal kingdom, yet close relatives are often regeneration incompetent. Why in the face of 'survival of the fittest' some animals regenerate but others do not remains a fascinating question. Planarian flatworms are well known and studied for their ability to regenerate from minute tissue pieces, yet species with limited regeneration abilities have been described even amongst planarians. Here we report the characterization of the regeneration defect in the planarian Dendrocoelum lacteum and its successful rescue. Tissue fragments cut from the posterior half of the body of this species are unable to regenerate a head and ultimately die. We find that this defect originates during the early stages of head specification, which require inhibition of canonical Wnt signalling in other planarian species. Notably, RNA interference (RNAi)-mediated knockdown of Dlac-ß-catenin-1, the Wnt signal transducer, restored the regeneration of fully functional heads on tail pieces, rescuing D. lacteum's regeneration defect. Our results demonstrate the utility of comparative studies towards the reactivation of regenerative abilities in regeneration-deficient animals. Furthermore, the availability of D. lacteum as a regeneration-impaired planarian model species provides a first step towards elucidating the evolutionary mechanisms that ultimately determine why some animals regenerate and others do not.

Yeast telomerase and the SUN domain protein Mps3 anchor telomeres and repress subtelomeric recombination.

Telomeres form the ends of linear chromosomes and protect these ends from being recognized as DNA double-strand breaks. Telomeric sequences are maintained in most cells by telomerase, a reverse transcriptase that adds TG-rich repeats to chromosome ends. In budding yeast, telomeres are organized in clusters at the nuclear periphery by interactions that depend on components of silent chromatin and the telomerase-binding factor yeast Ku (yKu). In this study, we examined whether the subnuclear localization of telomeres affects end maintenance. A telomere anchoring pathway involving the catalytic yeast telomerase subunits Est2, Est1, and Tlc1 is shown to be necessary for the perinuclear anchoring activity of Yku80 during S phase. Additionally, we identify the conserved Sad1-UNC-84 (SUN) domain protein Mps3 as the principal membrane anchor for this pathway. Impaired interference with Mps3 anchoring through overexpression of the Mps3 N terminus in a tel1 deletion background led to a senescence phenotype and to deleterious levels of subtelomeric Y' recombination. This suggests that telomere binding to the nuclear envelope helps protect telomeric repeats from recombination. Our results provide an example of a specialized structure that requires proper spatiotemporal localization to fulfill its biological role, and identifies a novel pathway of telomere protection.

Chromosome conformation maps in fission yeast reveal cell cycle dependent sub nuclear structure.

Successful progression through the cell cycle requires spatial and temporal regulation of gene transcript levels and the number, positions and condensation levels of chromosomes. Here we present a high resolution survey of genome interactions in Schizosaccharomyces pombe using synchronized cells to investigate cell cycle dependent changes in genome organization and transcription. Cell cycle dependent interactions were captured between and within S. pombe chromosomes. Known features of genome organization (e.g. the clustering of telomeres and retrotransposon long terminal repeats (LTRs)) were observed throughout the cell cycle. There were clear correlations between transcript levels and chromosomal interactions between genes, consistent with a role for interactions in transcriptional regulation at specific stages of the cell cycle. In silico reconstructions of the chromosome organization within the S. pombe nuclei were made by polymer modeling. These models suggest that groups of genes with high and low, or differentially regulated transcript levels have preferred positions within the S. pombe nucleus. We conclude that the S. pombe nucleus is spatially divided into functional sub-nuclear domains that correlate with gene activity. The observation that chromosomal interactions are maintained even when chromosomes are fully condensed in M phase implicates genome organization in epigenetic inheritance and bookmarking.

Biofunctionalization of the implant surface with different concentrations of a synthetic peptide (P-15).

OBJECTIVE: This study aimed at identifying the ideal concentration of a biofunctional surface coating of dental implants with a synthetic peptide (P-15). In a previous study, P-15 was shown to enhance osseointegration parameters. MATERIAL AND METHODS: Implants (modified ANKYLOS(®) A8; FRIADENT Plus(®) surface) with five different concentrations (0-400 µg/ml) of a P-15 coating as well as uncoated controls were inserted in the frontal bone of 45 adult domestic pigs. The histomorphometric and microradiographic findings for the coated implants were compared to those for the uncoated ones after 7, 14, and 30 days. RESULTS: No significant differences were observed comparing the peri-implant bone density between the coated and uncoated implants The bone-to-implant contact, as the primary histological parameter for osseointegration, showed high rates for all surfaces investigated (between 73.3 ± 17.9% for the control and 81.9 ± 15.2% for P15 20 µg/ml after 30 days). CONCLUSIONS: No significant benefit on osseointegration of a biofunctional P-15 coating of dental implants could be displayed in the present study.

Osseointegration of SLActive implants in diabetic pigs.

OBJECTIVES: Diabetes mellitus is currently classified as a relative contraindication for implant treatment because of microangiopathies with the consequence of impaired bone regeneration and higher rates of implant failure. The study aim was to investigate peri-implant bone formation in a diabetic animal model in comparison to healthy animals and to evaluate the differences between conventional (SLA(®) ) and modified (SLActive(®) ) titanium implant surfaces on osseointegration. MATERIAL AND METHODS: Each six implants were placed in the calvaria of 11 diabetic and 4 healthy domestic pigs. At 30 and 90 days after implant placement, the bone-to-implant contact (BIC) and bone density (BD) were appraised. Additionally, the expression of the bone-matrix proteins collagen type I and osteocalcin was evaluated at both points in time by using immunohistochemical staining methods. RESULTS: Overall, BIC was reduced in the diabetic group at 30 and 90 days. After 90 days, the SLActive(®) implants showed significantly higher BICs compared with the SLA(®) implants in diabetic animals. Peri-implant BD was higher in the SLActive(®) group at 30 and 90 days in healthy and diabetic animals. Collagen type I protein expression was higher using SLA(®) implants in diabetic pigs at 30 days. Values for osteocalcin expression were not consistent. CONCLUSIONS: The results indicate the negative effect of untreated diabetes mellitus on early osseointegration of dental implants. The modified SLA(®) surface (SLActive(®) ) elicited an accelerated osseointegration of dental implants, suggesting that a better prognosis for implant treatment of diabetic patients is possible.

Three-dimensional evaluation of condylar position after mandibular reconstruction with a fibula free flap-comparison of different surgical techniques.

Three-dimensional positional changes of the temporomandibular joint after mandible reconstruction using microvascular fibula flaps were investigated in 58 patients. The results of preoperative virtually planned surgery, intraoperative resection- and cutting-guided surgery, and non-guided surgery were compared. Pre- and postoperative computed tomography data of each patient were processed and superimposed digitally. The condyle deviations and rotations along the axes and planes of the skull, as well as Euclidean distances, were determined. Reliability analyses, descriptive statistics, and non-parametric tests were performed with the alpha level set at P = 0.05. Reliability proved to be excellent for all variables. The median Euclidean distance was 2.07 mm for the left condyle and 2.11 mm for the right condyle. Deviations of ≥ 10 mm occurred in nine (16%) cases. The maximum deviation occurred in the horizontal plane and the least deviation in the sagittal plane. Median rotation was ≤ 1.4° around all axes. The condylar displacements did not differ significantly between the different surgical techniques investigated. The three-dimensional measurement method applied is highly reliable for evaluating the three-dimensional condylar position after mandibular reconstruction.

Consistent Value of Two-Stage Pedicle Flaps in the Age of Microsurgical Maxillofacial Reconstruction.

Introduction: Up to the second half of the twentieth century, pedicled flaps marked the gold standard in reconstructive surgery. Followed by the introduction of microsurgical techniques, these flaps were increasingly abandoned. We conducted a retrospective study to determine the value of two-stage pedicle flaps in modern maxillofacial reconstruction. Material & Methods: A chart review from October 2017 to November 2020 was performed to identify patients who were treated by a two-stage pedicle flap in our Department of Oral and Maxillofacial Surgery. Results: A total of 31 patients, 17 female and 14 males received 36 two-stage pedicle flaps. All patients were in noticeably impaired health condition with a majority of ASA-score 3. The defect location mainly contained extraoral resections (58.3%). A variety of flaps were harvested consisting of buccal flaps, Abbe flaps, forehead flaps, deltopectoral flaps, nasolabial flaps, and a tubed flap. Discussion: The study outlines two indications for the use of two-stage pedicle flaps. Firstly, as a back-up strategy in heavily pre-treated wound beds and secondly in an almost contrarily indication as a first-choice reconstructive option of the facial skin in esthetic demanding cases. Conclusion: The timesaving and straight forward surgical approach as well as their low postsurgical complications and strong long-time success rates secure the two-stage pedicle flap a justified niche role in times of microsurgical maxillofacial reconstruction. Supplementary Information: The online version contains supplementary material available at 10.1007/s12663-021-01635-9.

Performance of different osteosynthesis materials in microvascular fibula free flap reconstruction.

Fibular free flap (FFF) is the main reconstructive choice for large mandibular defects. Recent improvements have been made regarding planning and surgical procedure, but choice of osteosynthesis material (OSM) for segment-fixation remains controversial. A retrospective cohort study obtained clinical and radiological data from FFF-patients. Data were screened for OSM, surgical procedure and complications as OSM fractures, loosening, exposure, or insufficient osseous consolidation. Eighty patients with FFF were included. Planning was CAD/CAM (n=29), Recon Guide (n=26) or without planning (n=25). OSM was 2.0mm-miniplates in standard (n=26), preformed (n=6), CAD/CAM (n=14) or ReconGuide (n=23) variation and 2.3mm-reconstruction-plates in standard (n=5) or CAD/CAM (n=6) variation. Complications were observed in 21 cases, fractures occurred 10 times overall, but with low rates for preformed (n=1), ReconGuide (n=3) and none for CAD/CAM. Analysis detected significant correlations between used OSM and plate exposure (p = 0.000), but none regarding fracture (p = 0.275), loosening (p = 0.714) or insufficient osseous consolidation (p = 0.208). No correlations were observed between complications and OSM (p = 0.609) or diagnosis (p = 0.716). Fixation of FFF segments for reconstruction is possible with various OSM providing good clinical outcome. No significant differences were detected regarding prevention of complications by any osteosynthesis material (miniplate vs. macroplate). Although no differences were detected, miniplate usage is advocated whenever clinically reasonable, due to easier reintervention possibilities and reduced implanted foreign material. Nevertheless, decision for ideal OSM must remain patient-specific and cannot be generalised.

A microdosing framework for absolute bioavailability assessment of poorly soluble drugs: A case study on cold-labeled venetoclax, from chemistry to the clinic.

This work presents an end-to-end approach for assessing the absolute bioavailability of highly hydrophobic, poorly water-soluble compounds that exhibit high nonspecific binding using venetoclax as a model drug. The approach utilizes a stable labeled i.v. microdose and requires fewer resources compared with traditional approaches that use radioactive 14 C-labeled compounds. The stable labeled venetoclax and internal standard were synthesized, then an i.v. formulation was developed. In the clinical study, female subjects received a single oral dose of venetoclax 100 mg followed by a 100-µg i.v. dose of cold-labeled 13 C-venetoclax at the oral time of maximum concentration (Tmax ). The i.v. microdose was prepared as an extemporaneous, sterile compounded solution on the dosing day by pharmacists at the clinical site. Several measures were taken to ensure the sterility and safety of the i.v. preparation. A sensitive liquid chromatography-tandem mass spectrometry method was developed to allow the detection of plasma levels from the i.v. microdose. Plasma samples were collected through 72 h, and pharmacokinetic parameters were estimated using noncompartmental methods. Postdosing sample analysis demonstrated the consistency of the preparations and allowed the precise calculation of the pharmacokinetic parameters based on the actual injected dose. The absolute bioavailability of venetoclax was estimated at 5.4% under fasting conditions. Venetoclax extraction ratio was estimated to be 0.06 suggesting that the fraction transferred from the enterocytes into the liver is limiting venetoclax bioavailability. The proposed framework can be applied to other highly hydrophobic, poorly water-soluble compounds that exhibit high nonspecific binding to support the understanding of their absorption and disposition mechanisms and guide formulation development.

Gobbling across landscapes: Eastern wild turkey distribution and occupancy-habitat associations.

Extensive restoration and translocation efforts beginning in the mid-20th century helped to reestablish eastern wild turkeys (Meleagris gallopavo silvestris) throughout their ancestral range. The adaptability of wild turkeys resulted in further population expansion in regions that were considered unfavorable during initial reintroductions across the northern United States. Identification and understanding of species distributions and contemporary habitat associations are important for guiding effective conservation and management strategies across different ecological landscapes. To investigate differences in wild turkey distribution across two contrasting regions, heavily forested northern Wisconsin, USA, and predominately agricultural southeast Wisconsin, we conducted 3050 gobbling call-count surveys from March to May of 2014-2018 and used multiseason correlated-replicate occupancy models to evaluate occupancy-habitat associations and distributions of wild turkeys in each study region. Detection probabilities varied widely and were influenced by sampling period, time of day, and wind speed. Spatial autocorrelation between successive stations was prevalent along survey routes but was stronger in our northern study area. In heavily forested northern Wisconsin, turkeys were more likely to occupy areas characterized by moderate availability of open land cover. Conversely, large agricultural fields decreased the likelihood of turkey occupancy in southeast Wisconsin, but occupancy probability increased as upland hardwood forest cover became more aggregated on the landscape. Turkeys in northern Wisconsin were more likely to occupy landscapes with less snow cover and a higher percentage of row crops planted in corn. However, we were unable to find supporting evidence in either study area that the abandonment of turkeys from survey routes was associated with snow depth or with the percentage of agricultural cover. Spatially, model-predicted estimates of patch-specific occupancy indicated turkey distribution was nonuniform across northern and southeast Wisconsin. Our findings demonstrated that the environmental constraints of turkey occupancy varied across the latitudinal gradient of the state with open cover, snow, and row crops being influential in the north, and agricultural areas and hardwood forest cover important in the southeast. These forces contribute to nonstationarity in wild turkey-environment relationships. Key habitat-occupancy associations identified in our results can be used to prioritize and strategically target management efforts and resources in areas that are more likely to harbor sustainable turkey populations.

Biofunctionalization of titanium implants with a biomimetic active peptide (P-15) promotes early osseointegration.

OBJECTIVES: The early stages of peri-implant bone formation play an essential role in the osseointegration and long-term success of dental implants. By incorporating bioactive coatings, this biofunctionalization of implant surfaces may enhance the attachment of the implant to the surrounding bone and stimulate bone regeneration. MATERIAL AND METHODS: To demonstrate faster osseointegration, the surfaces of dental implants were grit-blasted and acid-etched. They were then coated with hydroxyapatite (HA) and experimental implants were further coated with a biomimetic active peptide (P-15) in one of two concentrations. These biofunctionalized samples and controls with no peptide were placed in the forehead region of 12 adult pigs. Six animals were evaluated for a period of 14 or 30 days. RESULTS: Histomorphometric analysis demonstrated that the implants with the high concentration of P-15 had significantly higher percentage of bone-to-implant contact (BIC) at 14 (P=0.018) and 30 (P=0.015) days compared with the other groups. Both concentrations of P-15 showed increased peri-implant bone density compared to the control group at 30 days. CONCLUSION: Biofunctionalization of the implant surface with a biomimetic active peptide leads to significantly increased BIC rates at 14 and 30 days and higher peri-implant bone density at 30 days.

Larval bivalve shell morphometry: a new paleoclimatic tool?

The shells of the pelagic larvae of bivalve mollusks may be useful as paleoclimatic indicators. An inverse relationship between temperature and maximum size of larval shells within a particular population is reported for a number of Recent species. Changes in the dimensions of the prodissoconch-dissoconch boundary on juvenile specimens may reflect changes in the ambient temperature of marine environments.

Cretaceous bivalve larvae.

Exceptionally well preserved larval bivalve shells have been isolated from Late Cretaceous (Maestrichtian) sediments. Specimens were readily identified to familial level on the basis of gross morphology and hinge structures. Reconstruction of fossil larval ontogeny, linked with the distribution of adult stages, will provide an important interpretative tool in molluskan phylogenetic and paleoecologic studies.

Anaerobiosis and a theory of growth line formation.

Microstructural growth increments within the shells of numerous Recent and fossil molluscs are interpreted as reflections of alternating periods of shell deposition and dissolution, occurring during aerobic and anaerobic respiration, respectively. The acidic end products of anaerobic metabolism are neutralized by calcium carbonate from the shell, leaving a relatively insoluble organic residue at the mantle-shell interface. With the return of oxygenated conditions and resumption of aerobic respiration, this organic material is reincorporated within the shell. Inasmuch as metabolic changes are often synchronized with lunar or solar cycles (or both), we are led to the nearly paradoxical conclusion that, as a result of shell destructive processes, a relatively complete and detailed record of both short- and long-term growth is often preserved within the molluscan exoskeleton. Analyses of relationships between ambient oxygen concentrations and shell structural types may eventually prove useful, in paleoecological studies, for determination of dissolved oxygen gradients in Phanerozoic marine environments.

Larval development and dispersal at deep-sea hydrothermal vents.

Deep-sea hydrothermal vent communities exhibit an array of reproductive strategies. Although a few vent species undergo planktotrophic, high-dispersal modes of development, most exhibit relatively low dispersal, but probably free-swimming nonplanktotrophic development. This predominance of nonplanktotrophy may be largely a reflection of phylogenetic constraints on the vent colonizing taxa; intervent dispersal among these forms may be facilitated by reduced developmental rates in the cold abyssal waters away from the vents. It is proposed that for those vent species with nonplanktotrophic development, larval dispersal is a stepwise process with oceanic ridge axes serving as discrete dispersal corridors.

Growth of bivalves at deep-sea hydrothermal vents along the galapagos rift.

Direct measurements of shell growth of an unclassified mussel from active hydrothermal vents along the Galápagos Rift reveal growth rates of approxmately 1 centimeter per year for mature specimens. The largest mussel collected (with shell length of 18.4 centimeters) was estimated to be 19 +/- 7 years old at the time of sampling. Recorded growth rates are among the highest documented for deep-sea species.

Meeting report of the 7th Heidelberg Myeloma Workshop: today and tomorrow.

PURPOSE: The 7th Heidelberg Myeloma Workshop was held on April 5th and 6th, 2019 at the University Hospital Heidelberg. METHODS AND RESULTS: Main topics of the meeting were (1) diagnostics and prognostic factors, (2) role of immunotherapy in multiple myeloma (MM), (3) current therapy of MM, (4) biology and genomics of MM as well as (5) novel treatment concepts. A debate on the status of minimal residual disease (MRD) driven therapy was held. CONCLUSION: Diagnostics and treatment of newly diagnosed and relapsed MM are continuously evolving. While advances in the field of (single cell) genetic analysis now allow for characterization of the disease at an unprecedented resolution, immunotherapeutic approaches and MRD testing are at the forefront of the current clinical trial landscape.

A survey of inhalational anaesthetic abuse in anaesthesia training programmes.

This study aims to assess the prevalence and outcomes of inhalational anaesthetic abuse among anaesthesia training programmes. Online surveys were completed by chairpersons of academic anaesthesia training programmes in the United States. The response rate was 84% (106/126 programmes). Twenty-two percent of the departments had had at least one incident of inhalational anaesthetic abuse. Forty-eight percent (15/31) of the persons abusing inhalational anaesthetics were sent for rehabilitation. Only 22% (7/31) of those found to be abusing inhalational anaesthetics were ultimately able to return successfully to anaesthesia practice with sustained recovery. The mortality rate among individuals found abusing inhalational anaesthetics was 26% (8/31). The majority of the anaesthesia departments (97/104, 93%) did not have any pharmacy accounting of inhalational anaesthetics. This is the first published survey of inhalational anaesthesia abuse. Inhalational anaesthetic abuse should be considered in at-risk individuals or those with a history of substance abuse. The concern about substance abuse is not unique to American anaesthetists. Countries around the world deal with similar substance abuse issues.

The effect on bone regeneration of a liposomal vector to deliver BMP-2 gene to bone grafts in peri-implant bone defects.

Successful bone-implant osseointegration in large peri-implant bone defects is often difficult, even through autologous bone grafting. Recently, cell-mediated regional gene therapy was introduced to deliver potent morphogens or growth factors in regenerative medicine. We applied liposomal vectors carrying bone morphogenetic protein (BMP)-2 cDNA directly into freshly created peri-implant bone defects on pig calvariae, with or without autologous bone graft. The BMP-2 gene was efficiently introduced into immigrating cells and trabecular cells lining the marginal bone surrounding the bony defect. After 1 week, abundant BMP-2 protein was detected throughout the peri-implant bone defect by immunohistochemistry. At 4 weeks, BMP-producing cells were still present in the defect and peri-implant area, which significantly enhanced new bone formation, compared with the control groups. Interestingly within a week of BMP-2 gene delivery with bone grafts, most osteoblastic cells lining the grafted bone chips also produced BMP-2. Particulated bone was immediately reorganized into newly formed trabecular bone. Grafted bone without BMP-2 gene delivery was still scattered and new bone matrix formation was not detected until 4 weeks after bone grafting. In conclusion, direct application of the BMP-2 gene using a liposomal vector enhanced bone regeneration in a bony defect and gene delivery combined with bone graft could induce a rapid osseointegration of the bone-implant interface at earlier stage.