Three-dimensional recording of the human face with a 3D laser scanner.

Three-dimensional recording of the surface of the human body or of certain anatomical areas has gained an ever increasing importance in recent years. When recording living surfaces, such as the human face, not only has a varying degree of surface complexity to be accounted for, but also a variety of other factors, such as motion artefacts. It is of importance to establish standards for the recording procedure, which will optimise results and allow for better comparison and validation. In the study presented here, the faces of five male test persons were scanned in different experimental settings using non-contact 3D digitisers, type Minolta Vivid 910). Among others, the influence of the number of scanners used, the angle of recording, the head position of the test person, the impact of the examiner and of examination time on accuracy and precision of the virtual face models generated from the scanner data with specialised software were investigated. Computed data derived from the virtual models were compared to corresponding reference measurements carried out manually between defined landmarks on the test persons' faces. We describe experimental conditions that were of benefit in optimising the quality of scanner recording and the reliability of three-dimensional surface imaging. However, almost 50% of distances between landmarks derived from the virtual models deviated more than 2mm from the reference of manual measurements on the volunteers' faces.     

Atmungserregung und zentrale Erregbarkeit bei Ventilationsstörungen der Lunge und bei respiratorischer Acidose

Zusammenfassung Atemphysiologische Untersuchungen an 19 Patienten mit Ventilationsstörungen der Lunge mit dem Atmungsanalepticum Micoren ergeben eine Ventilationssteigerung um 60% des Ausgangswertes, eine Abnahme der arteriellen CO₂-Spannung und eine Zunahme des Blut-p_H, somit eine ventilationsbedingte Verschiebung der Blutgase in Richtung einer relativen respiratorischen Alkalose. Im Mittelpunkt der Untersuchung steht die Frage einer über die Atmungserregung hinaus bei der respiratorischen Acidose und Atemdepression erzielbaren Erregbarkeitsänderung der Zentren. Im Gegensatz zu Patienten ohne respiratorische Acidose läßt sich bei Kranken mit respiratorischer Acidose eine Steigerung der Erregbarkeit auf CO₂-Reiz und eine wahrscheinlich begrenzte Verzögerung der unter O₂-Atmung drohenden zentralen Depression nachweisen. Indikationen und klinische Gesichtspunkte einer medikamentösen Atmungserregung werden unter besonderer Berücksichtigung der respiratorischen Acidose besprochen.Mit freundlicher Unterstützung der Deutschen Forschungsgemeinschaft.     

Preliminary experience with a dynamic resorbable fixation device for craniosynostosis surgery

The advent of resorbable osteosynthesis material has revolutionized craniomaxillofacial surgery. The need to provide rigid bony fixation in the surgical treatment of craniofacial deformities has inspired an ongoing evolution of surgical innovations and implants. Stability of the plates has been improved, but the duration of their stability remains an ongoing problem. In infant craniofacial fixation, it is important to provide initial stability, but after 4 to 6 weeks, this is no longer required as the brain is rapidly expanding. Surgery was performed on 10 patients with sagittal suture synostosis with conventional suture resection, remodeling, and fixation with resorbable miniplate (PolyMax-RAPID) struts held in position with modeled resorbable pockets affixed to the neurocranium with resorbable screws placed across the resected suture between June 2004 and September 2008. All the patients presented a satisfactory aesthetic result without complications after at least 1-year follow-up. We present a further innovative method of craniofacial fixation in infants using resorbable plates as floating struts providing stability and at the same time controlled dynamic expansion of the cranial vault guided by brain growth.     

Selective distribution of GABA(A) receptor subtypes in mouse spinal dorsal horn neurons and primary afferents

In the spinal cord dorsal horn, presynaptic GABA_A receptors (GABA_ARs) in the terminals of nociceptors as well as postsynaptic receptors in spinal neurons regulate the transmission of nociceptive and somatosensory signals from the periphery. GABA_ARs are heterogeneous and distinguished functionally and pharmacologically by the type of α subunit variant they contain. This heterogeneity raises the possibility that GABA_AR subtypes differentially regulate specific pain modalities. Here, we characterized the subcellular distribution of GABA_AR subtypes in nociceptive circuits by using immunohistochemistry with subunit‐specific antibodies combined with markers of primary afferents and dorsal horn neurons. Confocal laser scanning microscopy analysis revealed a distinct, partially overlapping laminar distribution of α1–3 and α5 subunit immunoreactivity in laminae I–V. Likewise, a layer‐specific pattern was evident for their distribution among glutamatergic, γ‐aminobutyric acid (GABA)ergic, and glycinergic neurons (detected in transgenic mice expressing vesicular glutamate transporter 2–enhanced green fluorescent protein [vGluT2–eGFP], glutamic acid decarboxylase [GAD]67–eGFP, and glycine transporter 2 (GlyT2)–eGFP, respectively). Finally, all four subunits could be detected within primary afferent terminals. C‐fibers predominantly contained either α2 or α3 subunit immunoreactivity; terminals from myelinated (Aβ/Aδ) fibers were colabeled in roughly equal proportion with each subunit. The presence of axoaxonic GABAergic synapses was determined by costaining with gephyrin and vesicular inhibitory amino acid transporter to label GABAergic postsynaptic densities and terminals, respectively. Colocalization of the α2 or α3 subunit with these markers was observed in a subset of C‐fiber synapses. Furthermore, gephyrin mRNA and protein expression was detected in dorsal root ganglia. Collectively, these results show that differential GABA_AR distribution in primary afferent terminals and dorsal horn neurons allows for multiple, circuit‐specific modes of regulation of nociceptive circuits. J. Comp. Neurol. 520:3895–3911, 2012. © 2012 Wiley Periodicals, Inc.     

Atemarbeit und Dyspnoe in Ruhe und während körperlicher Belastung bei obstruktiver und restriktiver Lungeninsuffizienz

Zusammenfassung Es werden Untersuchungen über die Beziehung zwischen Atemarbeit und Ventilationsgröße bei Gesunden und bei Patienten mit obstruktiver und restriktiver Ventilationsstörung in Ruhe und während abgestufter körperlicher Belastung mitgeteilt. Hieraus werden quantitative Schlüsse auf Grad und Mechanismus der Ruhe- und Arbeitsdyspnoe bei obstruktiver und restriktiver Ventilationsstörung gezogen. Infolge der dynamisch beeinflußten Heterogenität der Lungenwiderstände und der Atemarbeit ist bei obstruktiver Ventilationsstörung das Ausmaß der Atemarbeit am größten. Bei restriktiver Ventilationsstörung ergibt sich das absolute und relative Ausmaß der Atemarbeit wie bei Gesunden aus der Statik und Volumendehnung, so daß die Atemarbeit auch bei hoher Belastung vom elastischen Widerstand allein bestimmt und damit homogen ist. Der Einfluß der Atemfrequenz und Atemtiefe und insbesondere der Frequenzabhängigkeit der Compliance bei obstruktiver Ventilationsstörung auf die Atemarbeit und Lage und Verlauf der Atemarbeits-Ventilations-Diagramme werden an Hand der Ergebnisse besprochen. Aus dem absoluten Ausmaß und dem Steigerungsgrad der Atemarbeit unter Belastungsbedingungen bei den verschiedenen Typen der ventilatorischen Insuffizienz werden die Probleme des Wirkungsgrades bzw. Nutzeffektes der Atemmuskulatur und der maximalen Arbeitsventilation in Beziehung zum Atemgrenzwert bei willkürlicher Hyerventilation sowie der Stoffwechselbedingungen der Atemmuskulatur und der Hämodynamik des Lungenkreislaufs bei körperlicher Arbeit diskutiert.     

Glycinergic neurons expressing enhanced green fluorescent protein in bacterial artificial chromosome transgenic mice

Although glycine is a major inhibitory transmitter in the mammalian CNS, the role of glycinergic neurons in defined neuronal circuits remains ill defined. This is due in part to difficulties in identifying these cells in living slice preparations for electrophysiological recordings and visualizing their axonal projections. To facilitate the morphological and functional analysis of glycinergic neurons, we generated bacterial artificial chromosome (BAC) transgenic mice, which specifically express enhanced green fluorescent protein (EGFP) under the control of the promotor of the glycine transporter (GlyT) 2 gene, which is a reliable marker for glycinergic neurons. Neurons expressing GlyT2-EGFP were intensely fluorescent, and their dendrites and axons could be visualized in great detail. Numerous positive neurons were detected in the spinal cord, brainstem, and cerebellum. The hypothalamus, intralaminar nuclei of the thalamus, and basal forebrain also received a dense GlyT2-EGFP innervation, whereas in the olfactory bulb, striatum, neocortex, hippocampus, and amygdala positive fibers were much less abundant. No GlyT2-EGFP-positive cell bodies were seen in the forebrain. On the subcellular level, GlyT2-EGFP fluorescence was colocalized extensively with glycine immunoreactivity in somata and dendrites and with both glycine and GlyT2 immunoreactivity in axon terminals, as shown by triple staining at all levels of the neuraxis, confirming the selective expression of the transgene in glycinergic neurons. In slice preparations of the spinal cord, no difference between the functional properties of EGFP-positive and negative neurons could be detected, confirming the utility of visually identifying glycinergic neurons to investigate their functional role in electrophysiological studies.