East-to-west human dispersal into Europe 1.4 million years ago

Stone tools stratified in alluvium and loess at Korolevo, western Ukraine, have been studied by several research groups1-3 since the discovery of the site in the 1970s. Although Korolevo's importance to the European Palaeolithic is widely acknowledged, age constraints on the lowermost lithic artefacts have yet to be determined conclusively. Here, using two methods of burial dating with cosmogenic nuclides4,5, we report ages of 1.42 ± 0.10 million years and 1.42 ± 0.28 million years for the sedimentary unit that contains Mode-1-type lithic artefacts. Korolevo represents, to our knowledge, the earliest securely dated hominin presence in Europe, and bridges the spatial and temporal gap between the Caucasus (around 1.85-1.78 million years ago)6 and southwestern Europe (around 1.2-1.1 million years ago)7,8. Our findings advance the hypothesis that Europe was colonized from the east, and our analysis of habitat suitability9 suggests that early hominins exploited warm interglacial periods to disperse into higher latitudes and relatively continental sites-such as Korolevo-well before the Middle Pleistocene Transition.

Single-cell transcriptomics defines keratinocyte differentiation in avian scutate scales

The growth of skin appendages, such as hair, feathers and scales, depends on terminal differentiation of epidermal keratinocytes. Here, we investigated keratinocyte differentiation in avian scutate scales. Cells were isolated from the skin on the legs of 1-day old chicks and subjected to single-cell transcriptomics. We identified two distinct populations of differentiated keratinocytes. The first population was characterized by mRNAs encoding cysteine-rich keratins and corneous beta-proteins (CBPs), also known as beta-keratins, of the scale type, indicating that these cells form hard scales. The second population of differentiated keratinocytes contained mRNAs encoding cysteine-poor keratins and keratinocyte-type CBPs, suggesting that these cells form the soft interscale epidermis. We raised an antibody against keratin 9-like cysteine-rich 2 (KRT9LC2), which is encoded by an mRNA enriched in the first keratinocyte population. Immunostaining confirmed expression of KRT9LC2 in the suprabasal epidermal layers of scutate scales but not in interscale epidermis. Keratinocyte differentiation in chicken leg skin resembled that in human skin with regard to the transcriptional upregulation of epidermal differentiation complex genes and genes involved in lipid metabolism and transport. In conclusion, this study defines gene expression programs that build scutate scales and interscale epidermis of birds and reveals evolutionarily conserved keratinocyte differentiation genes.

An In Vitro Model of Avian Skin Reveals Evolutionarily Conserved Transcriptional Regulation of Epidermal Barrier Formation

The function of the skin as a barrier against a dry environment evolved in a common ancestor of terrestrial vertebrates such as mammals and birds. However, it is unknown which elements of the genetic program of skin barrier formation are evolutionarily ancient and conserved. In this study, we determined the transcriptomes of chicken keratinocytes (KCs) grown in monolayer culture and in an organotypic model of avian skin. The differentiation-associated changes in global gene expression were compared with previously published transcriptome changes of human KCs cultured under equivalent conditions. We found that specific keratins and genes of the epidermal differentiation complex were upregulated during the differentiation of both chicken and human KCs. Likewise, the transcriptional upregulation of genes that control the synthesis and transport of lipids, anti-inflammatory cytokines of the IL-1 family, protease inhibitors, and other regulators of tissue homeostasis was conserved in the KCs of both species. However, some avian KC differentiation-associated transcripts lack homologs in mammals and vice versa, indicating a genetic basis for taxon-specific skin features. The results of this study reveal an evolutionarily ancient program in which dynamic gene transcription controls the metabolism and transport of lipids as well as other core processes during terrestrial skin barrier formation.

Convergent Evolution of Cysteine-Rich Keratins in Hard Skin Appendages of Terrestrial Vertebrates

Terrestrial vertebrates have evolved hard skin appendages, such as scales, claws, feathers, and hair that play crucial roles in defense, predation, locomotion, and thermal insulation. The mechanical properties of these skin appendages are largely determined by cornified epithelial components. So-called "hair keratins," cysteine-rich intermediate filament proteins that undergo covalent cross-linking via disulfide bonds, are the crucial structural proteins of hair and claws in mammals and hair keratin orthologs are also present in lizard claws, indicating an evolutionary origin in a hairless common ancestor of amniotes. Here, we show that reptiles and birds have also other cysteine-rich keratins which lack cysteine-rich orthologs in mammals. In addition to hard acidic (type I) sauropsid-specific (HAS) keratins, we identified hard basic (type II) sauropsid-specific (HBS) keratins which are conserved in lepidosaurs, turtles, crocodilians, and birds. Immunohistochemical analysis with a newly made antibody revealed expression of chicken HBS1 keratin in the cornifying epithelial cells of feathers. Molecular phylogenetics suggested that the high cysteine contents of HAS and HBS keratins evolved independently from the cysteine-rich sequences of hair keratin orthologs, thus representing products of convergent evolution. In conclusion, we propose an evolutionary model in which HAS and HBS keratins evolved as structural proteins in epithelial cornification of reptiles and at least one HBS keratin was co-opted as a component of feathers after the evolutionary divergence of birds from reptiles. Thus, cytoskeletal proteins of hair and feathers are products of convergent evolution and evolutionary co-option to similar biomechanical functions in clade-specific hard skin appendages.

TINCR is not a non-coding RNA but encodes a protein component of cornified epidermal keratinocytes

Long non-coding RNAs have been implicated in the regulation of a plethora of biological processes, yet it has been challenging to verify that they are truly not coding for proteins. Terminal differentiation-induced non-coding RNA (TINCR) is a 3.7-kilobase mRNA that is highly abundant in epidermal keratinocytes prior to cornification. Here, we report the presence of an evolutionarily conserved open reading frame in TINCR and the identification of peptides derived from this open reading frame in the proteome of human stratum corneum. Our results demonstrate that TINCR is a protein-coding RNA and suggest that the TINCR-encoded protein is involved in keratinocyte cornification.

Immunolocalization and phylogenetic profiling of the feather protein with the highest cysteine content

Feathers are the most complex skin appendages of vertebrates. Mature feathers consist of interconnected dead keratinocytes that are filled with heavily cross-linked proteins. Although the molecular architecture determines essential functions of feathers, only few feather proteins have been characterized with regard to their amino acid sequences and evolution. Here, we identify Epidermal Differentiation protein containing DPCC Motifs (EDDM) as a cysteine-rich protein that has co-evolved with other feather proteins. The EDDM gene is located within the avian epidermal differentiation complex (EDC), a cluster of genes that has originated and diversified in amniotes. EDDM shares the exon-intron organization with EDC genes of other amniotes, including humans, and a gene encoding an EDDM-like protein is present in crocodilians, suggesting that avian EDDM arose by sequence modification of an epidermal differentiation gene present in a common ancestor of archosaurs. The EDDM protein contains multiple sequence repeats and a higher number of cysteine residues than any other protein encoded in the EDC. Immunohistochemical analysis of chicken skin and skin appendages showed expression of EDDM in barb and barbules of feathers as well as in the subperiderm on embryonic scutate scales. These results suggest that the diversification and differential expression of EDDM, besides other EDC genes, was instrumental in facilitating the evolution of the most complex molecular architecture of feathers.

Comparative Analysis of Epidermal Differentiation Genes of Crocodilians Suggests New Models for the Evolutionary Origin of Avian Feather Proteins

The epidermis of amniotes forms a protective barrier against the environment and the differentiation program of keratinocytes, the main cell type in the epidermis, has undergone specific alterations in the course of adaptation of amniotes to a broad variety of environments and lifestyles. The epidermal differentiation complex (EDC) is a cluster of genes expressed at late stages of keratinocyte differentiation in both sauropsids and mammals. In the present study, we identified and analyzed the crocodilian equivalent of the EDC. The gene complement of the EDC of both the American alligator and the saltwater crocodile were determined by comparative genomics, de novo gene prediction and identification of EDC transcripts in published transcriptome data. We found that crocodilians have an organization of the EDC similar to that of their closest living relatives, the birds, with which they form the clade Archosauria. Notable differences include the specific expansion of a subfamily of EDC genes in crocodilians and the loss of distinct ancestral EDC genes in birds. Identification and comparative analysis of crocodilian orthologs of avian feather proteins suggest that the latter evolved by cooption and sequence modification of ancestral EDC genes, and that the amplification of an internal highly cysteine-enriched amino acid sequence motif gave rise to the feather component epidermal differentiation cysteine-rich protein in the avian lineage. Thus, sequence diversification of EDC genes contributed to the evolutionary divergence of the crocodilian and avian integuments.

Open reduction and internal rigid fixation of subcondylar fractures via an intraoral approach

Extraoral open reduction and rigid fixation of mandibular subcondylar fractures is controversial among surgeons. An intraoral approach with a percutaneous trocar and miniplates demonstrated satisfactory reduction. This technique can be more easily performed than a preauricular or submandibular incision, and risk of facial nerve damage is diminished. Early function with proper vertical dimension was restored with minimal postoperative morbidity.

[Mechanical properties of collagen or gelatine-stabilized blood clots]

Mechanical properties of blood clots stabilized with collagen (Pentapharm) and a gelatine (Gelastypt-M) sponge were compared with the help of thrombelastography and volumetric tests. The collagen songe was distinctly inferior to gelatine in stabilizing the clot against retraction. It appears that gelatine is a better material for filling large osseous defects that are subjected to mechanical stress.

[Treatment of obstructive sleep apnea with methods of orthognathic surgery]

The only surgical means available up to now for treating obstructive sleep apnea syndrome (OSAS) consisted in uvulopalatopharyngoplasty (UPPP), which failed to produce satisfactory results. The ultima ratio frequently resorted to was tracheotomy with all its medical and social drawbacks. Complete advancement of the maxillomandibular complex opens up new avenues for the treatment of upper airways obstruction. The present report is on 13 patients operated for polysomnographically established OSA. The maxillomandibular complex was brought as far forward as possible and esthetically justifiable. This operation was occasionally combined with other procedures to enhance upper airways function, such as conchotomy, palatopharyngoplasty, chin graft and reduction of tongue size. In 85% of the cases the apnea and hypopnea index (RDI) could be lowered to below 10 per hour sleep, i.e. these patients were cured.

[Evaluation of the hemostyptic properties of a collagen preparation]

In vitro tests were carried out to determine whether the haemostyptic properties of a collagen monomer were lost during the manufacturing process. An increased recalcification time and thromboplastin time as well as failure of the thrombocytes to adhere to the collagen fibres were observed. This indicates that blood coagulation can be attributed only to mechanical irritation of the blood corpuscles and not to the properties of the collagen molecules.

The use of autologous auricular cartilage for temporomandibular joint disc replacement: a preliminary report

The technique of harvesting auricular cartilage and its use in 22 patients (35 joints) is described. Follow-up was from 3 to 24 months. Pain relief was achieved in 90% of the cases. Function was equal or better to the preoperative situation in all cases.

Maxillomandibular advancement surgery in 23 patients with obstructive sleep apnea syndrome

Twenty-three patients with obstructive sleep apnea syndrome (OSAS) documented by polysomnography underwent maxillomandibular advancement via Le Fort I, and sagittal ramus split osteotomies followed by rigid fixation with miniplates and bicortical screws. Partial turbinectomies and septal reconstruction were simultaneously performed. Pre- and post-operative cephalometric radiographs were analyzed by computer. Hyoid position and posterior airway space changes did not correlate with clinical success. The surgical success (respiratory disturbance index less than 10) with maxillomandibular advancement was 65%. The total desaturations below 90% greatly decreased. Ninety-six percent of patients were subjectively and objectively improved.

[Reoperation of root amputation with titanium pin]

A clinical follow-up of 238 patients confirmed the good results of root amputation with titanium pin for apical closure. An analysis of reoperations because of failure of primary surgery rendered similarly good results. Therefore the use of a titanium pin will not impair the success of secondary surgery for root amputation which shows good results most of the time anyway.

[Comparison of two operative techniques for odontogenic maxillary sinusitis]

The bone lid method introduced by Lindorf (1974) was compared with a conservative procedure leaving a small defekt in the malar buttres. The operation is partly done with an endoscope. The results of 60 operated maxillary sinuses show a higher incidence of dysesthesia and postoperative discomfort in the bone lid method. Thus this method should in our opinion be reserved to special indications.

Dysplastic collagen fibrils in the human vocal fold. An electron microscope study

Electron microscope studies made on biopsy samples of the human vocal cord from patients suffering from chronic hoarseness revealed pathological changes in both the collagen fibrils and the elastic fibres. There was splitting and fracturing of the collagen fibrils and lacuna or cyst formation in the elastic fibres, or even the complete fibre degeneration. Further investigations must be undertaken in order to establish whether the changes observed are of a primary or secondary nature.