Annetrudi Kress

Josef Klingler's models of white matter tracts: influences on neuroanatomy, neurosurgery, and neuroimaging.

During the 1930s, white matter tracts began to assume relevance for neurosurgery, especially after Cajals work. In many reviews of white matter neurobiology, the seminal contributions of Josef Klingler (1888-1963) and their neurological applications have been overlooked. In 1934 at the University of Basel under Eugen Ludwig, Klingler developed a new method of dissection based on a freezing technique for brain tissue that eloquently revealed the white matter tracts. Klingler worked with anatomists, surgeons, and other scientists, and his models and dissections of white matter tracts remain arguably the most elegant ever created. He stressed 3-dimensional anatomic relationships and laid the foundation for defining mesial temporal, limbic, insular, and thalamic fiber and functional relationships and contributed to the potential of stereotactic neurosurgery. Around 1947, Klingler was part of a Swiss-German group that independently performed the first stereotactic thalamotomies, basing their targeting and logic on Klinglers white matter studies, describing various applications of stereotaxy and showing Klinglers work integrated into a craniocerebral topographic system for targeting with external localization of eloquent brain structures and stimulation of deep thalamic nuclei. Klinglers work has received renewed interest because it is applicable for correlating the results of the fiber-mapping paradigms from diffusion tensor imaging to actual anatomic evidence. Although others have described white matter tracts, none have had as much practical impact on neuroscience as Klingers work. More importantly, Josef Klingler was an encouraging mentor, influencing neurosurgeons, neuroscientists, and brain imaging for more than three quarters of a century.

Ultrastructural studies of oogenesis in some european amphibians

SummaryOogenesis was studied in adult Rana temporaria and Rana esculenta with the electron microscope. It takes an almost identical course in both animals. Three types of yolk bodies were found. These differ in their genesis as well as in their morphological appearance in the mature oocyte. In accordance with their morphogenesis they were named: 1. mitochondrial matrix yolk (MMY), 2. intracristal yolk (ICY) and 3. vesicular yolk (VY). MMY is formed within the mitochondrial matrix and has a centre to centre spacing of the crystalline lattice of approximately 165 Å. ICY is formed within the cristae and has a centre to centre spacing of the crystalline lattice of 85 Å. Vesicular yolk is formed through uptake of pinocytotic vesicles into multivesicular bodies and has a centre to centre spacing of the crystalline lattice of approximately 95 Å. The formation of the three types of crystalline inclusion bodies is discussed in view of a possible intraoocytic or extraoocytic origin of the incorporated material.

Oogenesis in the Marsupial Stripe-Faced Dunnart, Sminthopsis macroura

The timetable of oogenesis in Sminthopsis macroura is accelerated like in other marsupials showing relatively early maturation of the female. On the day of parturition (day 0) migration of primordial germ cells to the indifferent gonads has been completed. Follicular growth seems not to correspond to the biphasic pattern, in which oocyte and follicle grow synchronously until antral stages when only the follicle increases in size, but shows a continuous growth of the oocyte and the follicle up to the time of ovulation. During primordial and early primary follicle stage a paranuclear complex is present in the oocyte, consisting mainly of smooth tubules of endoplasmic reticulum. Cortical granules appear early in oocytes in secondary follicles. The conspicuous inclusions in the antral follicle are the clusters of electron-lucent vesicles in the oocyte. These inclusions grow from multivesicular bodies (MVB), which are formed from Golgi and endoplasmic reticulum vesicles. Further increase in the size of MVB involves the incorporation of endocytic vesicles and the coalescence of larger vesicles. The polarized nature of the oocyte at ovulation is due in part to the to accumulation of these vesicles in the cytoplasm opposite the eccentrically placed nuclear material.

Observations during embryonic development in the genus Doto (Gastropoda, Opisthobranchia)

While working on taxonomic problems in the family Dotoidae and comparing the Mediterranean and Atlantic species (Schmekel & Kress, in the Press), it became apparent that very little embryological information was available for this group, other than that published by Alder & Hancock (1845–55), Pelseneer (1911), Miller (1958, Ph.D. Thesis, University of Liverpool) and Thompson (1967). In the course of studies on the changes in egg-capsule volume in different nudibranch species (Kress, 1971, 1972) a fresh attempt has been made to obtain some comparative data on egg and capsule sizes and on the course and rate of embryonic development in the three species of Doto most commonly found in the Plymouth area, namely D. coronata (Gmelin, 1791), D. pinnatifida (Montagu, 1804) and D. fragilis (Forbes, 1838).

Yolk-platelet formation in oocytes of Xenopus laevis (Daudin)

SummaryYolk-platelet formation in the South African clawed toad, Xenopus laevis, was studied with the electron microscope. A dual mode of formation was found. One being associated with mitochondria, the other with the Golgi complex. These two ways of yolk formation are named yolk formation I and yolk formation II respectively. Yolk formation I involves an extensive uptake of pinocytotic vesicles, whilst yolk formation II takes place within large Golgi vesicles surrounded by a coat of lipid droplets entirely without participation of pinocytotic activities. Thus it is concluded that yolk platelet I formation represents an extraoocytic synthesis as opposed to the intraoocytic synthesis of yolk platelet II formation.

On the European species of Eubranchus [Mollusca Opisthobranchia]

On the basis of extensive material from Plymouth an attempt has been made to determine the specific limits of the European species of the eolid genus Eubranchus Forbes. From a study of the living animals, jaws, radulae and reproductive systems, it is concluded that five species can be recognized as occurring commonly in Britain, Eubranchus tricolor Forbes (= Galvina viridula Bergh), E. farrani (Alder & Hancock), E. pallidus (Alder & Hancock), E. cingulatus (Alder & Hancock) and E. exiguus (Alder & Hancock). These species are all variable in coloration, but they can nevertheless be easily distinguished by coloration as well as by morphological and ecological characteristics. A further species, E. doriae (Trinchese) from the Mediterranean, was also examined and appears to be distinct. No material of Eubranchus rupiurn (Moller) and E. vittatus (Alder & Hancock) was available for examination, but these are provisionally maintained as distinct species. The European species of Eubranchus are compared with species from other parts of the world in an attempt to decide how many genera should be recognized. It is concluded that the armature of the penis and the liver branching do not form good generic characters, and that consequently Capellinia is to be regarded as a junior synonym of Eubranchus .

Ultrastructural Changes in the Uterine Luminal and Glandular Epithelium during the Oestrous Cycle of the Marsupial Monodelphis domestica (Grey Short-Tailed Opossum)

Ultrastructural changes in the endometrium associated with the oestrous cycle were studied in the South American marsupial Monodelphis domestica. The most conspicuous changes include the height and the differentiation of the uterine luminal and glandular epithelium, which consists of ciliated and non-ciliated cells. The glandular epithelium attains its maximum development during oestrus, the luminal epithelium at postoestrus. A distinct increase in the number of ciliated cells can be observed during pro-oestrus, reaching a maximum number at oestrus; this is followed by a process of deciliation. The presence of solitary cilia on the apices of non-ciliated cells is very conspicuous during all oestrous stages and can best be seen on the luminal epithelium. These findings differ from the observations in eutherian mammals, where solitary cilia are only found in the immature uterus or after ovariectomy. The secretory activity of non-ciliated cells of the luminal epithelium is hardly noticeable along the apical membrane and stains only very faintly with Alcian blue. The glandular epithelium cells are filled apically with exocytotic vesicles at oestrus and early postoestrus. However, in contrast to the cervical gland cells, they hardly stain with Alcian blue, indicating that mucins of a different type must be present. Mechanisms for the remodelling of the luminal and glandular epithelium are especially conspicuous at metoestrus and early pro-oestrus and include the presence of autolysosomes, residual bodies and apoptotic bodies. In the endometrial stroma, around the uterine glands, macrophages accumulate and attain a typical oestrous stage-dependent appearance during their phagocytotic activities.

Ultrastructural indications for autosynthetic proteinaceous yolk formation in amphibian oocytes.

The formation of proteinaceous yolk is a main feature during amphibian oogenesis. The main bulk is built up by a process called heterosynthesis. The precursor complex vitellogenin is synthesized in the liver, transported by the bloodstream to the ovary, where the oocytes sequester the material by means of endocytosis. This pathway has been described in detail by many authors. The ultrastructural study of amphibian oocytes indicates on the other hand a small but distinct contribution of the oocyte itself towards yolk formation. This process has been called autosynthesis and starts before the onset of heterosynthetic activities. The cell organelles possibly involved in yolk-recursor and yolk-platelet formation are the nuclear envelope, annulate lamellae, endoplasmic reticulum, Golgi complex, GERL and mitochondria. The aim of this paper is to discuss the data, mainly of ultrastructural nature, so far accumulated during the study of autosynthesis. It is hoped to stimulate more biochemically orientated research in this field.

Conceptus Polarity and Cell-Zona Adhesion during Early Cleavage (Fertilized Tubal Egg to 8-Cell Stage) in the Marsupial Sminthopsis macroura

This study outlines the ultrastructural changes that occur in Sminthopsis macroura tubal zygotes to the 8-cell stage in relation to observations of development in vitro, oocyte polarity and cell-zona adhesion. The extremely polarized mature oocytes and zygotes have nuclear material at one pole and accumulated vesicular bodies at the other. The first division is associated with extrusion of vesicular bodies and some cytoplasm as a membrane-bound yolk mass into the perivitelline space. Early cleavage is accompanied by the appearance of an extensive, highly structured extracellular matrix (ECM) comprised of amorphous substance, granules and filaments. At the 2- and 4-cell stage the decrease in density of the ECM in the vicinity of the blastomeres may facilitate cell-zona contact. At the 8-cell stage, discharge of vesicular bodies, which mostly appear to be empty, may contribute to the ECM by increasing the area of plasma membrane for synthesis of a hyaluronan-like ECM. As in other marsupials, the precedence of cell-zona adhesion over cell-cell contacts prevents morula formation. The earliest cell-zona contacts appear when microvilli contact the zona in the uterine zygote 12–16 h after uterine entry and continue at later stages. This early contact is possible because of the absence of a dense subzonal ECM in this species. Between late zygote and late 4-cell stage the cytoplasm also contains, beside a large amount of vesicular bodies, demarcated areas where smooth endoplasmic reticulum encloses mitochondria, vesicles, granular material and fibrillar arrays. The latter develop in the late zygote stage and are found outside demarcated areas as well, often closely surrounding large vesicles, probably helping vesicle extrusion. A putative germ plasm was identified at the 4-cell stage.

A scanning electron microscope study of notum structures in some dorid nudibranchs (Gastropoda: Opisthobranchia)

Skin structures of nine different species of dorid nudibranchs were examined at the scanning electron microscope and the light microscope levels. From these observations the animals are grouped into three categories. 1. Dorids with spicule-supported tubercles carrying a sensory knob ( Rostanga rubra, Jorunna tomentosa, Onchidoris sparsa, Onchidoris pusilla ). 2. Dorids with small sensory papillae set in pits and distributed randomly between projecting spicules ( Aegires punctilucens ). 3. Dorids with tubercles differing in shape from one species to another, invested with numerous spicules but without conspicuous sensory structures. The tips of the tubercles do, however, contain single sensory epithelium cells ( Archidoris pseudoargus, Acanthodoris pilosa, Onchidoris muricata, Onchidoris bilamellata ).