Mammoth ivory was the most suitable osseous raw material for the production of Late Pleistocene big game projectile points.

Late Pleistocene societies throughout the northern hemisphere used mammoth and mastodon ivory not only for art and adornment, but also for tools, in particular projectile points. A comparative analysis of the mechanical properties of tusk dentine from woolly mammoth (Mammuthus primigenius) and African elephant (Loxodonta africana) reveals similar longitudinal stiffness values that are comparable to those of cervid antler compacta. The longitudinal bending strength and work of fracture of proboscidean ivory are very high owing to its substantial collagen content and specific microstructure. In permafrost, these properties can be fully retained for thousands of years. Owing to the unique combination of stiffness, toughness and size, ivory was obviously the most suitable osseous raw material for massive projectile points used in big game hunting.

Comparing touch senses of naïve and expert panels through treated hair swatches: which associated wordings correlate with hair physical properties?

OBJECTIVES: This study (i) compared the sense of touch between a naïve and expert panels, under visual or blind conditions, using differently treated hair swatches and (ii) explored possible common wordings used by both panels and their possible links with some physical properties of hairs. METHODS: Two sets of 15 hair swatches of Caucasian and Chinese origins were differently treated (bleached, permed, brushed, etc.) or organized (root-tip vs. tip-root). These were evaluated by tactile assessments by two panels (105 naïve consumers and 10 hair experts) under visual or blind conditions, in two geographical locations. A series of 17 defined antonym adjectives, as descriptors, allowed responses of each panel to being scored and their preference mappings to being defined on a like-dislike scale. Hair swatches were measured and assessed by various instrumental techniques (bending, diameter, cuticle cohesion, alignments of hair). RESULTS: Apart from a few overlaps, all 15 hair swatches were well differentiated by both panels which showed a global agreement, making experts reliable assessors. Only three descriptors among 17 correlated with some objective measurements. Tactile-visual assessments differ from those performed tactile blind in both panels. Agreements between both panels appear, however, closer under tactile-blind conditions. CONCLUSION: Trained hair experts were confirmed as reliable representatives of a larger and naïve cohort, viewed as consumers. Hair swatches were well differentiated by both panels, with comparable descriptor rankings.

Neural driven angiogenesis by overexpression of nerve growth factor.

Mechanisms regulating angiogenesis are crucial in adjusting tissue perfusion on metabolic demands. We demonstrate that overexpression of nerve growth factor (NGF) in brown adipose tissue (BAT) of NGF-transgenic mice elevates both mRNA and protein levels of vascular endothelial growth factor (VEGF) and VEGF-receptors. Increased vascular permeability, leukocyte-endothelial interactions (LEI), and tissue perfusion were measured using intravital microscopy. NGF-stimulation of adipocytes and endothelial cells elevates mRNA expression of VEGF and its receptors, an effect blocked by NGF neutralizing antibodies. These data suggest an activation of angiogenesis as a result of both: stimulation of adipozytes and direct mitogenic effects on endothelial cells. The increased nerve density associated with vessels strengthened our hypothesis that tissue perfusion is regulated by neural control of vessels and that the interaction between the NGF and VEGF systems is the critical driver for the activated angiogenic process. The interaction of VEGF- and NGF-systems gives new insights into neural control of organ vascularization and perfusion.

Femur window--a new approach to microcirculation of living bone in situ.

BACKGROUND: The processes of osteogenesis, bone remodelling, fracture repair and metastasis to bone are determined by complex sequential interactions involving cellular and microcirculatory parameters. Consequently studies targeting the analysis of microcirculatory parameters on such processes should mostly respect these complex conditions. However these conditions could not yet be achieved in vitro and therefore techniques that allow a long-term observation of functional and structural parameters of microcirculation in bone in vivo at a high spatial resolution are needed to monitor dynamic events, such as fracture healing, bone remodelling and tumor metastasis. METHODS: We developed a bone chamber implant (femur window) for long-term intravital microscopy of pre-existing bone and its microcirculation at an orthotopic site in mice preserving the mechanical properties of bone. After bone chamber implantation vascular density, vessel diameter, vessel perfusion, vascular permeability and leukocyte-endothelial interactions (LEIs) in femoral bone tissue of c57-black mice (n=11) were measured quantitatively over 12 days using intravital fluorescence microscopy. Furthermore a model for bone defect healing and bone metastasis in the femur window was tested. RESULTS: Microvascular permeability and LEIs showed initially high values after chamber implantation followed by a significant decrease to a steady state at day 6 and 12, whereas structural parameters remained unaltered. Bone defect healing and tumor growth was observed over 12 and 90 days respectively. CONCLUSION: The new femur window design allows a long-term analysis of structural and functional properties of bone and its microcirculation quantitatively at a high spatial resolution. Altered functional parameters of microcirculation after surgical procedures and their time dependent return to a steady state underline the necessity of long-term observations to achieve unaltered microcirculatory parameters. Dissection of the complex interactions between bone and microcirculation enables us to evaluate physiological and pathological processes of bone and may give new insights especially in dynamic events e.g. fracture healing, bone remodeling and tumor metastasis.

[Open arthrolysis in preserved joint surface geometry]. / Offene Ellenbogenarthrolyse bei erhaltener Gelenkflächengeometrie.

This review article discusses the operative treatment options for release of essentially extracartilaginous contractures of the elbow (referred to as extrinsic contractures). Indications, preoperative work-up, specific operative strategy and techniques, rehabilitation, possible complications, and results are discussed and compared. Special reference is made to the technique of sequential surgical release based on the transhumeral approach. This technique makes it possible to optimize the articular offset while preserving the static and dynamic stabilizers of the joint. Treatment of contractures of the elbow remains dangerous and delicate. It deserves experienced surgical handling in order to avoid complications. Thus, it remains to be hoped that qualified management will help to improve the relatively mediocre functional results.

A Ni2+ binding motif is the basis of high affinity transport of the Alcaligenes eutrophus nickel permease.

Amino acid exchanges in the Alcaligenes eutrophus nickel permease (HoxN) were constructed by site-directed mutagenesis, and their effects on nickel ion uptake were investigated. Mutant hoxN alleles were expressed in Escherichia coli, and activity of the altered permeases was examined via a recently described physiological assay (Wolfram, L., Friedrich, B., and Eitinger, T. (1995) J. Bacteriol. 177, 1840-1843). Replacement of Cys-37, Cys-256, or Cys-318 by alanine did not severely affect nickel ion uptake. This activity of a C331A mutant was diminished by 60%, and a similar phenotype was obtained with a cysteine-less mutant harboring four Cys to Ala exchanges. Alterations in a histidine-containing sequence motif (His-62, Asp-67, His-68), which is conserved in microbial nickel transport proteins, strongly affected or completely abolished transport activity in the E. coli system. The analysis of HoxN alkaline phosphatase fusion proteins implied that His-62, Asp-67, and His-68 exchanges did not interfere with overall membrane topology or stability of the nickel permease. These mutations were reintroduced into the A. eutrophus wild-type strain. Analyses of the resulting HoxN mutants indicated that exchanges in the histidine motif led to a clearly decreased affinity of the permease for nickel ion.

The Alcaligenes eutrophus protein HoxN mediates nickel transport in Escherichia coli.

HoxN, an integral membrane protein with seven transmembrane helices and a molecular mass of 33.1 kDa, is involved in high-affinity nickel transport in Alcaligenes eutrophus H16. From genetic analyses, it has been concluded that HoxN is a single-component ion carrier. To investigate this assumption, hoxN was introduced into Escherichia coli. The recombinant strain showed significantly enhanced nickel uptake in a short-interval assay. Likewise, growth in the presence of 63NiCl2 yielded a more than 15-fold-increased cellular nickel content. The HoxN-based nickel transport activity could also be demonstrated in a physiological assay: an E. coli strain coexpressing hoxN and the urease operon of Klebsiella aerogenes exhibited urease activity 10-fold greater than that in the strain lacking a functional hoxN. These results strongly suggest that HoxN is sufficient to operate as a nickel permease. Multiple sequence alignment of HoxN and four other bacterial membrane proteins implicated in nickel metabolism revealed two conserved signatures which may play a role in the nickel translocation process.

Construction and properties of a triprotein containing the high-affinity nickel transporter of Alcaligenes eutrophus.

The high-affinity nickel transporter of Alcaligenes eutrophus H16 is encoded by gene hoxN, which maps within the hydrogenase gene cluster of megaplasmid pHG1. A tripartite gene fusion was constructed, consisting of (i) the Escherichia coli lacZ gene for beta-galactosidase, (ii) a segment encoding an endoproteolytically cleavable peptide, and (iii) the A. eutrophus gene hoxN. An E. coli strain harboring this construct (plasmid pCH307) efficiently produced the corresponding triprotein upon induction. A broad-host-range derivative of pCH307 was shown to complement an A. eutrophus HoxN- mutant.

Percutaneous penetration of hair dyes.

Scalp penetration of 7 hair dyes (oxidative and direct) that occurs under conditions of hair dye usage was evaluated for both rhesus monkey and man using 14C labeled materials by quantifying their absorbtion via urine assays. Both species showed a remarkably similar pattern of dye penetration. The extent of scalp penetration is slightly higher for direct dyes but in neither case does it exceed 1% of the applied dose.

Transformed world of industrial infrared analysis.

Infrared spectroscopy is a widely used industrial tool for the structural and compositional analysis of organic, inorganic, or polymeric samples and for quality control of raw materials and commercial products. The increased sensitivity of Fourier transform infrared has greatly enhanced the problem-solving opportunities for infrared in research and development laboratories. Examples are given where FT-IR has been particularly effective in the rapid identification of very small quantities of product from unusual chemical reactions without the necessity of separating the product from the reactants. The good SNR attainable with FT-IR, with the data processing capability, has increased the ability to observe very small differences between the spectra of supposedly similar polymers. These differences have been related to changes in processing conditions and polymer physical properties. FT-IR has been used successfully to characterize structural changes in petroleum products, which may occur as a result of chemical and physical treatment. FT-IR spectra of a series of acrylonitrile-containing copolymers have also been correlated with NMR monomer sequence data to delineate sequence-sensitive infrared bands.

Frictional properties of skin.

To gain a more fundamental understanding of the frictional properties of skin, various parameters (hydration, oils, surfactants, etc) affecting skin friction were evaluated using a rotational friction technique. The rotational device utilized a motor-driven wheel. The wheel and drive shaft were connected to the motor through a flexible rubber coupling in such a way that friction encountered by the wheel caused a lateral displacement of the drive shaft which was monitored by a photocell and recorded on a strip-chart recorder.