PubMed Health⌕ Search

Biomedical subjects

J Neubert

Publications and source records attributed to J Neubert.

33 records · Page 2Linked to original sources
PubMed1981

Changes in the microstructure of the vestibular apparatus of tadpoles (Rana temporaria) developed in simulated weightlessness.

The vestibular apparatus of tadpoles (Rana temporaria) exposed to simulated weightlessness was examined by electron microscopy. Extended exposure to simulated weightlessness is followed by significant alterations in the sensory epithelia and also in the otolith membrane. Large vacuoles, filled with necrobiotic mitochondria and fragments of endoplasmic reticulum, were concentrated in the region where an otolith membrane covers the hair cells but were mostly absent in zones of the epithelia with undifferentiated cells. The number of otoconia in the otolith membrane was diminished. The results were compared with data from space flight experiments and some concordance was noted. The possible connection between some unusual behavior of the tadpoles after weightlessness simulation and the structural alterations in the gravitational sensors was discussed.

Animals↗
PubMed1979

Ultrastructural development of the vestibular system under conditions of simulated weightlessness.

Electronmicroscopy was used to track the development of the gravity system of frog embryos and larvae which have bred for 5, 7, and 10 d after egg fertilization under conditions of simulated weightlessness on the fast-running horizontal clinostat. Although no differences in the morphologic structure of the organ between test and control animals could be found up to 7 d of development, there is a significant accumulation of vacuoles in sensory epithelia of frog larvae develpoping for 10 d (stage 17) in simulated zero G.

Animals↗
PubMed1975

Influence of simulated weightlessness on the rate of anomalies of the flour beetle Tribolium confusum.

Experiments with Tribolium confusum showed that the morphological characteristics of the beetles are modified by simulated weightlessness (fast running clinostat). Because of possible side effects due to differences in fertility of inbred lines, the first experiments were made with a genetically heterogeneous stock. Thereafter experiments were confirmed with inbred beetles. For both stocks a rise of mainly wing anomalies resulted from rotation of whole cultures of beetles within horizontal tubes. The extent to which these anomalies are teratogenetic or genetic has not yet been analysed in detail.

Animals↗
PubMedDate not supplied

Readaptation of the vestibuloocular reflex to 1g-condition in immature lower vertebrates (Xenopus laevis) after micro- or hypergravity exposure.

The effects of altered gravitational conditions (AGC) on the development of the static vestibulo-ocular reflex (VOR) and readaptation to 1g were investigated in the amphibian Xenopus laevis. Tadpoles were exposed to microgravity during the German Space Mission D-2 for 10 days, using the STATEX closed survival system, or to 3g for 9 days during earth-bound experiments. At the beginning of AGC, the tadpoles had not yet developed the static VOR. The main results were: (i) Tadpoles with microgravity- or 3g-experience had a lower gain of the static VOR than the 1g-controls during the 2nd and 5th post-AGC days. (ii) Readaptation to response levels of 1g-reared controls usually occurred during the following weeks, except in slowly developing tadpoles with 3g-experience. Readaptation was less pronounced if, during the acute VOR test, tadpoles were rolled from the inclined to the normal posture than in the opposite test situation. It is postulated that (i) gravity is necessarily involved in the development of the static VOR, but only during a period including the time before onset of the first behavioural response; and (ii) readaptation which is superimposed by the processes of VOR development depends on many factors including the velocity of development, the actual excitation level of the vestibular systems and the neuroplastic properties of its specific pathways.

Adaptation, Physiological↗
PubMedDate not supplied

[Angiolipoma of the maxillary sinus as a cause of recurring sinusitis-like symptoms].

A review of the literature shows that intraoral lipomas are more common than they are generally believed to be. The clinical course of a case with unusual localization, size and clinical manifestation of an angiolipoma of the maxillary sinus is described. Differential diagnosis with other types of intraoral lipomas is made.

Adult↗
PubMedDate not supplied

[Gardner's syndrome].

Gardner's syndrome is a dominant, familial cancer syndrome. It is characterized by intestinal polyposis, multiple osteomas, especially of the skull, and various soft tissue tumors (such as epidermal cysts or desmoid tumors). Late age of onset is the main feature distinguishing it from other polyposis syndromes. The risk of malignancies developing during adult life is virtually 100%, and colectomy is mandatory. Since extracolonic manifestations are very often the first symptoms seen by the physician, it is very important to know that they are indicative of Gardner's syndrome and associated with intestinal polyposis.

Adult↗
PubMedDate not supplied

[Computer documentation of malignomas of the mouth, jaws and face using the BAIK system].

The computer-supported documentation of head and neck tumors by means of the BAIK-system is presented. The experience after introducing the project to clinical routine use in patient's treatment is outlined. The subsystems of BAIK are critically reviewed for this purpose. Although we realize some drawbacks of BAIK the system proved to be useful for our application, mainly because of its strong retrieval functions, combining coded and free text data manipulation.

Computer Systems↗
PubMedDate not supplied

[Surgical expansion of midpalatal suture by means of modified Le Fort I osteotomy].

From 1984 to 1987 thirty-nine adult patients suffering from a transverse maxillary deficiency were operated by a modified Le-Fort-I-osteotomy to facilitate the following rapid orthopedic expansion. A horizontal osteotomy was made through the lateral wall of the maxilla from the interior lateral aspect of the piriform aperture to the pterygomaxillary suture, which was also sectioned. After the operation the palatal expansion appliance (Biedermann-Hyrax-screw) was normally activated one one-quarter turn twice a day until the desired expansion was achieved. In each case this surgical orthodontic procedure showed to be an excellent method to correct transverse maxillary deficiencies. This procedure is especially indicated in patients with bilateral crossbite. Unilateral crossbites can also be treated this way, if a later Le-Fort-I-osteotomy is necessary to correct sagittal or vertical discrepancies.

Adult↗