Biomedical subjects
Publications and source records attributed to G Reiss.
The present review describes some problems of citation of medical articles basing on own experiences. The citation and bibliography should be carefully basing on the several given instructions.
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N-Linked protein glycosylation in most eukaryotic cells initiates with the transfer of the oligosaccharide Glc3Man9GlcNAc2 from the lipid carrier dolichyl pyrophosphate to selected asparagine residues. In the yeast Saccharomyces cerevisiae, alg mutations which affect the assembly of the lipid-linked oligosaccharide at the membrane of the endoplasmic reticulum result in the accumulation of lipid-linked oligosaccharide intermediates and a hypoglycosylation of proteins. Exploiting the synthetic growth defect of alg mutations in combination with mutations affecting oligosaccharyl transferase activity (Stagljar et al., 1994), we have isolated the ALG6 locus. alg6 mutants accumulate lipid-linked Man9GlcNAc2, suggesting that this locus encodes an endoplasmic glucosyltransferase. Alg6p has sequence similarity to Alg8p, a protein required for glucosylation of Glc1Man9GlcNAc2.
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It is current opinion that the intercellular spaces of the stria vascularis represent a closed compartment isolated from the endolymph by the tight junctions of the marginal cells and from the perilymph by the junctional complexes of the basel cells. However, it has not yet been investigated whether these two barriers meet at the stria margins toward Reissner's membrane and the spiral prominence. Possible candidates for this sealing could be junctions between the spindle-shaped cells. In the present study freeze-fracture replicas of guinea pig specimens fixed in the presence of filipin were used in order to investigate the junctions of the spindle-shaped cells and to localize the cholesterol in their plasma membrane. Replicas reveal that, below the belt-like apical zonula occludens, the basolateral plasma membranes of the spindle-shaped cells adjacent to each other and to the basal cells are joined over their entire extension by a large number of junctional strands intermingled with numerous filipin-cholesterol-complexes. Gap junctions are present in the meshes formed by these junctional strands. Thus, the plasma membrane of the spindle-shaped cells shows morphological and cytochemical characteristics which indicate that they are the anatomical components completing the barrier isolating the intrastrial compartment from the surrounding fluids.
Experience has shown that a special cochlear-implant procedure, the so-called "soft surgery technique", may help to retain the remaining function of the inner ear. The morphological changes in the organ of Corti after an atraumatic implant procedure were examined using an animal model. The insertion was facilitated by coating the electrode with Healon. Scanning electron microscopy of the organ of Corti revealed only minor changes in the inner and outer hair cells. In all cases connective tissue was found sealing the implant as a reaction of the cochlea to the intracochlear implant.
Clinical and experimental data appear to indicate that by means of an extremely gentle procedure, known as the "soft surgery" technique, during the insertion of the electrode carrier of the cochlear implant, some level of existing residual hearing can be preserved. By means of an animal model, morphologic changes in the organ of Corti after use of this atraumatic implantation technique were investigated with two types of implants and the results compared. Insertion of the implants was facilitated by lubrication with Healon. In the scanning electron microscopy picture of the organ of Corti, only minor changes in the outer hair cells were observed. As an obligatory reaction of the cochlea to the intracochlear implant, a connective tissue envelope was found around the electrode carrier.
For the evaluation of functional inner ear lesions caused by an autoimmune-induced labyrinthitis, transiently evoked otoacoustic emissions (TEOAEs) were detected in guinea pigs before and after transfer of sensitized lymphocytes from animals suffering from a labyrinthitis induced by the foreign protein keyhole limpet hemocyanin (KLH). Initially TEOAEs were detectable from 47 of 62 ears (76%) in healthy guinea pigs. These animals then were used as recipients for sensitized lymphocytes from donors exclusively. Three months after cell transfer the incidence of TEOAEs was reduced to 48% in animals receiving lymphocytes from donors sensitized with KLH intradermally and intracochlearly. In recipients of lymphocytes from donors sensitized only intradermally and in untreated animals no significant alteration of the TEOAE incidence was found. These findings showed strong correlation with those from scanning electron microscopy of the organ of Corti, indicating that the measurement of TEOAE is a useful, time-saving tool for the detection of cochlear dysfunction caused by sensitized lymphocytes in experimental animal. The present findings also show that the migration of sensitized lymphocytes actually leads to functional lesions in the cochlea.
We want to report on our experiences with the percutaneous trephination using a 2.35 mm round dental drill with serrated saws around it, a "Rosenbohrer". It is a methodically similar activity as described by J. Zentner [11]. From 1981 to 1992 519 patients were treated and 546 trephinations were performed. At the beginning this treatment was only used in connection with intracerebral bleedings and biopsies. In a considerable short time the indication could be extended to the subdural hematoma, tumor cyst, obstructive hydrocephalus as well as to the abscess and the subdural epyema. The rate of infection was 1.28% and the risk of bleeding 0.36%. In our opinion the advantages of this small electrical trephination are the easy handling, the universal use and mobility and the avoidable risk of anesthesia as well as the sterilisation at the same time and the stopping of blood, caused by the contact surface friction.
Sensorineural hearing loss is a common problem in the otolaryngologist's practice, with autoimmune disease of the inner ear being one possible cause. The restoration of auditory function in some patients following immunosuppressive therapy has created a desire to define and understand this disease better. Because of the lack of a well defined detection method to identify this entity clinically, this study was undertaken in order to provide an animal model for autoimmune disease of the inner ear. Previous studies with guinea pigs have demonstrated that sensitized lymphocytes from the systemic circulation migrate to the labyrinth during an immune response in the inner ear. The aim of this study was to prove the capacity of sensitized lymphocytes to transfer autoimmune inner ear disease, and to describe the resulting morphological and physiological changes. Therefore two groups of sensitized lymphocytes partially labelled with a radioactive marker from inbred guinea pigs with an immune response within the inner ear were injected into the bloodstream of naive recipient animals. Most of the labelled cells were observed in the apical turn of the experimental cochlea, while only few cells were detectable in the control cochleas. In addition, the absence of otoacoustic emissions and the loss of outer hair cells observed by electron microscopy were interpreted as a sign of damage caused by the provoked immunopathologic mechanism. The results are discussed as a possible model for a sympathetic cochleolabyrinthitis.
The entire organ of Corti of guinea pig was investigated by scanning electron microscopy (SEM), using it's high resolving power to observe the three dimensional fine structure of the cochlea. Inner ear tissue of the normal guinea pig was conductively stained (OTOTO-method) for SEM. The relationship between the sensory cells and supporting cells was shown. SEM gives a nice overview of the surface structure of three dimensional organs like the inner ear. We conclude that bulk specimens of the organ of Corti are more advantageous than piece specimens in acoustic physiological as well as pathological research studies.
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Treatment of large sessile polyps or tumors of the rectum is a challenging surgical problem. A retrospective review of the posterior surgical approach for the treatment of rectal tumors was conducted to assess the efficacy of this operative technique. Thirty-three patients were reviewed. Thirteen patients underwent transanal excision, and 3 of these patients had malignant disease. One patient returned to the operating room because of postoperative bleeding. Twelve patients underwent transsacral excision of tumors, 6 of which were malignant lesions in the mid to high rectum. One patient developed a fistula. One benign tumor recurred. Eight patients underwent abdomino-sacral excision, and seven of these were for rectal cancer. Local control was unsuccessful with this technique in one patient. There were no deaths in this series. The complication rate was acceptable, and the morbidity of local pain was offset by sphincter preservation and return of normal bowel function. This approach seems very useful for a variety of rectal tumors.
Titanium screw taps and titanium fixtures were investigated by SEM before and after experimental use. Peri-implant bone surfaces were examined immediately after surgery and 5 months after implantation by SEM using the SE mode, backscattered electron imaging, and EDX analysis to detect titanium contamination of the bone specimens. The Ti content of the livers, kidneys, and lungs of six Göttingen minipigs, which had received two screw implants each, was determined using flameless atomic absorption spectroscopy and compared to a control group with no implants. Results showed that Ti particles were abraded and deposited on the bone surface during the preparation of implant beds. Five months after placement, particles were no longer observed on the bone surface next to the implants. Determination of the Ti concentration of the inner organs showed that the lungs contained the highest amount of titanium. The Ti content of the kidneys and livers was much lower. All values differed significantly from those of the control group (P < .01).
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Inner ear tissue of the normal guinea pig was conductively stained (OTOTO-method) for SEM investigations. The Hensen's cells of the organ of Corti were removed using a micromanipulator inside the SEM. By this method atypical bodies of sensory and supporting cells were revealed in the apical turns of the cochlea. Atypical sensory cells showed great variations in size and shape. Several had no contact to Deiter's cells and no or only one nerve supply at their basal end. Atypical Deiter's cells showed alterations in shape and in the form of their phalangeal processes. Additionally altered parts of the organ of Corti were isolated by micromanipulation and embedded for correlative TEM-investigations.
Using an experimental animal model consequences of operatively changed modes of liver perfusion on hepatic function could be demonstrated. Three groups of 5 animals each (swine) had the following operations: Group I received a portocaval shunt. In group II in addition to the portocaval shunt a vein graft was interposed between the vena cava and the portal vein. In group III an arterialization of this graft was performed in addition to the two operations mentioned above. Follow-up at defined time intervals included clinical, laboratory and histological data. It could be demonstrated that animals in group II and III showed normal parameters as far as behavior and controlled lab data are concerned. Animals of group I had significantly poorer results in all tests. In this study we found that direct portal perfusion was not necessary for a normal liver function and could be fully compensated both by caval venous blood and by arterialized caval venous blood.