Biology subjects

Haberthür, D.

Publications and source records attributed to Haberthür, D..

6 recordsLinked to original sources

bioRxiv2024

Contrast-Enhanced Micro-CT Imaging of a Foetal Female Pelvic Floor Reveals Anatomical Details

BackgroundThe pelvic floor is a highly important structure for the stability of the pelvis, providing support for the organs that lie within it. Until today, the detailed anatomy of the female perineal centre and the exact course of surrounding muscles remain controversial. This paper demonstrated a method to non-destructively obtain high-resolution contrast-enhanced x-ray microtomography images from a long-fixed sample and thereby aimed to contribute to the detailed anatomical knowledge about the female pelvic floor. Materials and MethodsA human foetal pelvis of 20-21 weeks gestational age, formalin-fixed for 4 years, was immersed in Lugol solution and tomographically scanned periodically to document the staining process. The influence of the former fixation time was addressed by comparison with a short time fixed mouse pelvis. High-resolution imaging was performed by {micro}CT, and the detailed analysis of the anatomy was supported by segmentation and 3D reconstruction. ResultsLugol staining of long-fixed tissue worked well and showed no disadvantages compared to short-fixed tissue. Lugol staining and high-resolution {micro}CT images provided a nicely stained image- stack with clearly identifiable tissue types. The anatomy of the foetal pelvis and its structures were resolved in detail. Interconnections between the external anal sphincter, the bulbospongiosus muscle and the superficial transverse perineal muscle could be shown within the perineal centre. There was no evidence for a skeletal muscle that corresponded to the formerly described deep transverse perineal muscle, instead there was cloudy-looking tissue, most likely smooth muscle fibres dispersed in connective tissue in a 3-D arrangement. ConclusionsX-ray microtomography of Lugol-stained tissue is an excellent method to gain anatomical details in high resolution, in a non-invasive and non-destructive way, independently of the fixation time. Using this method, the topographical relationships of the pelvic floor muscles could be illustrated, showing their linkage within the perineal centre.

developmental biology↗

bioRxiv2023

Microtomographic investigation of a large corpus of cichlids

A large collection of cichlids (N=133) from Lake Victoria in Africa spanning a length range of 6 to 18 cm was nondestructively imaged using micro-computed tomography. We describe our method to efficiently obtain three-dimensional tomographic datasets of the oral and pharyngeal jaws and the whole skull of these fishes for accurately describing their morphology. The tomographic data we acquired (9.8 TB of projection images) yielded 1.5 TB of three-dimensional image stacks used for extracting the relevant features of interest. Herein we present our method and an outlook on analyzing the acquired data; a morphological description of the oral and pharyngeal jaws of the fishes, a three-dimensional geometric morphometrics analysis of landmark features on the fish skulls, and a robust method to automatically extract the otoliths of the fishes from the tomographic data.

ecology↗

bioRxiv2020

Automated segmentation and description of the internal morphology of human permanent teeth by means of micro-CT

Micro-CT is a powerful tool to analyze and visualize the internal morphology of human permanent teeth. It is increasingly used for investigation of epidemiological questions to provide the dentist with the necessary information required for successful endodontic treatment. The aim of the present paper was to propose an image processing method to automate parts of the work needed to fully describe the internal morphology of human permanent teeth. One hundred and four human teeth were scanned on a high-resolution micro-CT using an automatic specimen changer. Python code in a Jupyter notebook was used to verify and process the scans, prepare the datasets for description of the internal morphology and to measure the apical region of he tooth. The presented method offers an easy, non-destructive, rapid and efficient approach to scan, check and preview micro-computer tomographic datasets of a large number of teeth. It is a helpful tool for the detailed description and characterization of the internal morphology of human permanent teeth using automated segmentation by means of micro-CT with full reproducibility and high standardization.

physiology↗

bioRxiv2019

Pulmonary acini exhibit complex changes during postnatal rat lung development

Pulmonary acini represent the functional gas-exchanging units of the lung. Due to technical limitations, individual acini cannot be identified on microscopic lung sections. To overcome these limitations, we imaged the right lower lobes of instillation-fixed rat lungs from postnatal days P4, P10, P21, and P60 at the TOMCAT beamline of the Swiss Light Source synchrotron facility at a voxel size of 1.48 m. Individual acini were segmented from the three-dimensional data by closing the airways at the transition from conducting to gas exchanging airways. For a subset of acini (N=268), we followed the acinar development by stereologically assessing their volume and their number of alveoli. We found that the mean volume of the acini increases 23 times during the observed time-frame. The coeffcients of variation dropped from 1.26 to 0.49 and the difference between the mean volumes of the fraction of the 20 % smallest to the 20 % largest acini decreased from a factor of 27.26 (day 4) to a factor of 4.07 (day 60), i.e. shows a smaller dispersion at later time points. The acinar volumes show a very large variation early in lung development and homogenize during maturation of the lung by reducing their size distribution by a factor of 7 until adulthood. The homogenization of the acinar sizes hints at an optimization of the gas-exchange region in the lungs of adult animals and that acini of different size are not evenly distributed in the lungs. This likely leads to more homogeneous ventilation at later stages in lung development.

physiology↗

bioRxiv2019

Reptile-like physiology in Early Jurassic stem-mammals

There is uncertainty regarding the timing and fossil species in which mammalian endothermy arose, with few studies of stem-mammals on key aspects of endothermy such as basal or maximum metabolic rates, or placing them in the context of living vertebrate metabolic ranges. Synchrotron X-ray imaging of incremental tooth cementum shows two Early Jurassic stem-mammals, Morganucodon and Kuehneotherium, had lifespans (a basal metabolic rate proxy) considerably longer than comparably sized living mammals, but similar to reptiles, and that Morganucodon had femoral blood flow rates (a maximum metabolic rate proxy) intermediate between living mammals and reptiles. This shows maximum metabolic rates increased evolutionarily before basal rates, and that contrary to previous suggestions of a Triassic origin, Early Jurassic stem-mammals lacked the endothermic metabolism of living mammals.One Sentence Summary Surprisingly long lifespans and low femoral blood flow suggest reptile-like physiology in key Early Jurassic stem-mammals.View Full Text

paleontology↗

bioRxiv2019

Adaptation Mechanism Of The Adult Zebrafish Respiratory Organ To Endurance Training

In order to study the adaptation scope of the fish respiratory organ and the O2 metabolism due to endurance training, we subjected adult zebrafish (Danio rerio) to endurance exercise for 5 weeks. After the training period, the swimmer group showed a significant increase in swimming performance, body weight and length. In scanning electron microscopy of the gills, the average length of centrally located primary filaments appeared significantly longer in the swimmer than in the non-trained control group (+6.1%, 1639 {micro}m vs. 1545 {micro}m, p=0.00043) and the average number of secondary filaments increased significantly (+7.7%, 49.27 vs. 45.73, p=9e-09). Micro-computed tomography indicated a significant increase in the gill volume (p=0.048) by 11.8% from 0.490 mm3 to 0.549 mm3. The space-filling complexity dropped significantly (p=0.0088) by 8.2% from 38.8% to 35.9%., i.e. making the gills of the swimmers less compact. Respirometry after 5 weeks showed a significantly higher oxygen consumption (+30.4%, p=0.0081) of trained fish during exercise compared to controls. Scanning electron microscopy revealed different stages of new secondary filament budding, which happened at the tip of the primary lamellae. Using BrdU we could confirm that the growth of the secondary filaments took place mainly in the distal half and the tip and for primary filaments mainly at the tip. We conclude that the zebrafish respiratory organ - unlike the mammalian lung - has a high plasticity, and after endurance training increases its volume and changes its structure in order to facilitate O2 uptake.\n\nAuthor summaryAdult zebrafish show an increase of their gill volume after endurance training, likely to adjust for the increased oxygen demand measured with respirometry during swimming.

developmental biology↗