0000000000025802
AUTHOR
Holger Jastrow
Anatomy online: presentation of a detailed WWW atlas of human gross anatomy--reference for medical education.
We present an online anatomy atlas based on the Visible Human Project (VHP) of the US National Library of Medicine. The objective is to provide original unlabeled as well as labeled sections of the human body of high quality and resolution on the Internet, for use in basic and continuing medical education. For a representative overview of the body, 370 axial sections were selected from the male and female data base of the VHP with special regard to regions of clinical interest. Each section is accompanied by its corresponding computer tomography (CT) image and, if available, magnetic resonance images (MRI) for quick and easy comparison of morphologic and radiologic structures. The sections …
Teaching and learning gross anatomy using modern electronic media based on the visible human project
This article reviews online (Internet) anatomy projects and multimedia productions (books and CD-ROMs) based on the Visible Human Project (VHP) of the United States National Library of Medicine. The focus of these projects and productions is on the teaching of 3D anatomy using the digitized sections of the visible human male and female. The article also provides information about the VHP, its goals and what it has achieved thus far.
Identification of a β-Dystroglycan Immunoreactive Subcompartment in Photoreceptor Terminals
PURPOSE Mutations in the dystrophin-associated glycoprotein complex (DGC) cause various forms of muscular dystrophy. These diseases are characterized by progressive loss of skeletal muscle tissue and by dysfunctions in the central nervous system (CNS). The CNS deficits include an altered electroretinogram, caused by an impaired synaptic transmission between photoreceptors and their postsynaptic target cells in the outer plexiform layer (OPL). The DGC is concentrated in the OPL but its exact distribution is controversial. Therefore, the precise distribution of beta-dystroglycan, the central component of the DGC, within the OPL of the mature chick retina, was determined. METHODS Double immuno…
Changes in the Three Dimensional Structure of Synaptic Ribbons in the Pineal Gland of the Guinea-Pig Caused by Constant Light
Synaptic bodies (SBs) are dynamic synaptic organelles of afferent synapses of the retina, inner ear, lateral line organ and pineal gland in vertebrates. When investigated in a transmission electron microscope, their electron-dense rod-like, round or irregular profiles are surrounded by electron-lucent vesicles. The three-dimensional structure of pineal SBs is not precisely known. Pineal glands of two guinea-pigs (one kept under an LD cycle of 12:12 h; one kept in constant light for 8 weeks) were investigated. SBs were reconstructed in three dimensions to visualise morphological changes in constant light. Transmission electron microscope micrographs from up to 18 serial sections with a known…
Adaptation of the disector method to rare small organelles in TEM sections exemplified by counting synaptic bodies in the rat pineal gland
The disector is the only objective method for quantifying particles of variable size in a given volume. With this method, cell organelles are identified on adjacent sections, but only those present in one section are counted. When counting extremely rare structures in transmission electron microscope sections (physical disector), the usual procedure of counting on electron micrographs is limited for economic reasons (e.g. micrographs highly outnumbering the investigated structures). Hence, to apply this unbiased stereological method, a modification of the physical disector concerning 3 aspects has been developed. (1) The prerequisite of screening large corresponding tissue areas (here appro…
The shape of synaptic ribbons in the rat pineal gland
Under the transmission electron microscope, synaptic ribbons (SRs) of the mammalian pineal gland appear as rod-like organelles. Their three-dimensional structure is not precisely known. In the present study, pineal SRs were investigated using serial sections obtained from rats killed at noon and midnight. The shape of the SRs was reconstructed based on SR profile length and the number of sections in which the profiles were contained. The results obtained show that SRs are basically flat plate-like structures with polymorphic lateral edges. Reconstructions of SRs revealed that they had average dimensions of 300x150x35 nm and were 19.3% larger at night than at day; the difference in SR size p…
Tomographic reconstruction reveals the morphology of a unique cellular organelle, the aggregated macrotubules (Macrotubuli aggregati) of human retinal horizontal cells.
Abstract Horizontal cells of the human retina contain unique tubular organelles that have a diameter which is about 10 times larger than that of microtubules (∼230 nm). These macrotubuli in most cases form regular aggregates. Therefore we propose to introduce them as Macrotubuli aggregati in the Terminologia histologica. Tomographic investigation of the structures revealed that the walls of the tubules most probably consist of intermediate filaments running nearly parallel to each other and show somewhat regularly attached ribosomes on their inner and also outer surface. About 2% of the organelles exhibit double- to multiple layered walls and less than 1% resemble large scrolls. The tubules…
The Innervation of Taste Buds in the Soft Palate and Circumvallate Papilla of the Rat as Revealed by the Zinc Iodide-Osmium Tetroxide Technique.
The taste buds in the soft palate and the circumvallate papillae of the rat were investigated by the zinc iodide-osmium tetroxide technique. In addition, electron micrographs of taste buds stained with this method were presented for the first time. Differences in taste bud structures were found between the examined regions. The taste buds of the soft palate showed a complicated plexus of intragemmal nerve fibers. Some fibers exhibited terminal polymorphic swellings. Single branches could be traced close to the space of the taste pore. In the soft palate, the taste bud cells remained unstained, whereas in the circumvallate papillae of the tongue, a subpopulation of taste bud cells could be s…
Analysis of synaptic bodies in the Sprague–Dawley rat pineal gland under extreme photoperiods
Synaptic bodies (SBs) are small, prominent organelles in pinealocytes, most probably involved in signal transduction processes. To check the influence of the photoperiod on their shape plasticity and number we chose two extreme lighting conditions, i.e. 20 h of illumination followed by 4 h of darkness (LD 20:4) versus (LD 4:20). Pineal glands were assessed at 0, 4 and 13 h after dark onset. Under both conditions reconstructed SBs were plates or ribbons but never spheres and there were no obvious differences in morphology. Photoperiodic changes in SB profile size and number were investigated: application of the established method for SB quantification based on single section profile counts (…
A differential role of CREB phosphorylation in cAMP-inducible gene expression in the rat pineal
In the rat pineal gland cAMP mediates nocturnal induction of the enzyme arylalkylamine N-acetyltransferase (AA-NAT) as well as of transcription factors such as inducible cAMP early repressor (ICER), Fos-related antigen-2 (Fra-2) and JunB. Cyclic AMP stimulates the phosphorylation of the DNA binding protein cAMP response element binding protein (CREB). While cAMP-induced CREB phosphorylation appears to be a prerequisite for AA-NAT and ICER gene expression, it is not known whether CREB phosphorylation accounts for the full cAMP response of the two genes. Furthermore, the significance of CREB phosphorylation in cAMP-activated Fra-2 and JunB transcription is unknown. In the present in vitro stu…
Terminal nerve in the mouse-eared bat (Myotis myotis): ontogenetic aspects.
As in other mammals, ontogenesis of the terminal nerve (TN) in the mouse-eared bat (Myotis myotis) starts shortly after the formation of the olfactory placode, a derivative of the ectoderm. During development of the olfactory pit, proliferating neuroblasts thicken the placodal epithelium and one cell population migrates toward the rostroventral tip of the telencephalon. Here they accumulate in a primordial terminal ganglion, which successively divides into smaller units. Initial fibers of the TN can be distinguished from olfactory fibers in the mid-embryonic period. The main TN fiber bundle (mfb) originates from the anteriormost ganglion in the nasal roof, whereas one or more inconstant sma…
Bizarre alterations of the morphology of pineal synaptic bodies under constant light and an evaluation of suitable 3D-reconstruction software
Three dimensional (3D) reconstruction and modelling software was evaluated to find a procedure suitable for visualization of small subcellular structures in transmission electron microscope images. The method applied in this study demonstrates bizarre alterations of the structure of synaptic bodies (SBs) in pinealocytes of the guinea-pig pineal gland caused by constant illumination. It can, in general, be used for any 3D reconstruction from serial sections. Pineal glands of five guinea-pigs (two kept under a LD cycle of 12:12 h; three kept in constant light, for 4 months) were investigated. SBs consist of an electron-dense centre with attached vesicles. Under normal lighting conditions most…
On the use and value of new media and how medical students assess their effectiveness in learning anatomy.
The new media have become widely used tools in medical instruction today. But are they regarded as useful by students training to become medical doctors? What are students' most important criteria for a good CD-ROM or valuable Internet resources? To answer these questions, and to obtain definite data on the use of new media, we distributed a questionnaire to preclinical medical and dental students of the Johannes Gutenberg University in Mainz, Germany. The evaluation of 397 questionnaires demonstrates that 94.9% of the students use personal computers; 91.6% of the 85.8% who own a computer have access to the Internet. The Internet is used at least once a week by 70.1% of students for private…