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PubMedDate not supplied

In vitro conversion of Borrelia burgdorferi to cystic forms in spinal fluid, and transformation to mobile spirochetes by incubation in BSK-H medium.

The purpose of this study was to examine the structural alterations of Borrelia burgdorferi when exposed to spinal fluid. Normal, mobile spirochetes were inoculated into spinal fluid, and the spirochetes were converted to cysts (spheroplast L-forms) after 1-24 h. When these cystic forms were transferred to a rich BSK-H medium, the cysts were converted back to normal, mobile spirochetes after incubation for 9 to 17 days. The cultures were examined by dark field microscopy (DFM), interference contrast microscopy (ICM) and transmission electron microscopy (TEM). When neuroborreliosis is suspected, it is necessary to realize that B. burgdorferi can be present in a cystic form, and these cysts have to be recognized by microscopy. This study may also explain why cultivation of spinal fluid often is negative with respect to B. burgdorferi.

Borrelia Infections↗
PubMed2002

TOF-SIMS and XPS-investigations of ion implanted single crystal 1b-diamonds.

Near surface zones of (48)Ti- and (52)Cr-implanted single crystal diamonds (1b-MCD) were characterized by XPS, TOF-SIMS and white light interference microscopy (WLI). By the combination of WLI and TOF-SIMS it was possible to calibrate the depth scale of TOF-SIMS and XPS depth profiles quantitatively. The adjustment of TOF-SIMS and XPS elemental depth profiles in the implantation maximum increases the quantitative detection limit of the implanted elements by more than two orders of magnitude and enables the interpretation of results from wear simulation experiments. Peak fits of XPS C(1s)-photolines indicate the fraction and chemical nature of carbide-like structures in the implantation zone. Qualitative hints on carbide compounds are possibly included in the reconstructed TOF-SIMS spectra but this information can presently only be extracted with the aid of XPS analyses.

Journal Article↗
PubMed2002

[Reproducibility of measuring retinal nerve fiber density. Comparison of optical coherence tomography with the nerve fiber analyzer and the Heidelberg retinal tomography device].

BACKGROUND: Glaucoma is associated with a progressive loss of retinal ganglion cell axons and the evaluation of the thickness of the retinal nerve fibre layer (RNFL) is important for early diagnosis and follow-up. Results of RNFL thickness measurements may vary according to the devices used. Therefore, the present study has analysed and compared the reproducibility of data obtained with three different instruments. METHODS: RNFL thickness was determined using a circular identification line around the optic nerve head by optical coherence tomography (OCT), a Heidelberg Retina Tomograph (HRT) and a Nerve Fiber Analyser (NFA). Each eye was tested six times. The values for RNFL thickness were calculated for the superior, inferior, nasal and temporal areas. A one-way analysis of variance with random effects was chosen to estimate the variance components. The intraclass correlation coefficient (ICC) as a measure of reliability and the coefficient of variation (CV%) as a measure of precision were determined to estimate the reproducibility of RNFL thickness measurements. RESULTS: With all three instruments, the reproducibility of measurements between the superior, inferior, temporal and nasal areas did not differ significantly suggesting that reproducibility does not depend on the thickness of the RNFL. Data obtained by NFA showed the highest ICC values (0.9) and lowest CV% values (7.0), followed by those obtained by HRT (reliability ICC 0.8; precision CV% 12). A markedly lower degree of reproducibility was found for the OCT compared to NFA and HRT (reliability ICC 0.5; precision CV% 15). CONCLUSION: The comparison of RNFL thickness measurements with OCT, NFA, and HRT showed that the NFA yielded the most reliable results followed by HRT.

Adolescent↗
PubMed2001

Association between multiple sclerosis and cystic structures in cerebrospinal fluid.

BACKGROUND: The aim of the study was to search for infectious agents in the cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS). PATIENTS AND METHODS: CSF from ten patients with the diagnosis relapsing remitting MS and from five controls without MS were examined by transmission electron microscopy (TEM), dark field microscopy (DF), interference contrast microscopy (ICM) and UV-microscopic examination of acridine orange staining (AO). All CSF samples from patients and controls were cultured. RESULTS: Cystic structures were observed in CSF of all ten patients by AO and TEM. DF revealed eight cyst-positive patients out of nine. One of five control persons had such structures in the CSF; this person had suffered from erythema migrans. Spirochete or rod-like structures emerged after culturing two of the MS patient CSF samples and these structures could be propagated. CONCLUSION: A significant association of CSF cysts and MS was identified in this small study among residents in a coastal area of southern Norway. The cysts could be of spirochetal origin. Our study may encourage other researchers to study larger patient groups.

Adult↗
PubMed1981

Outgrowth and maintenance of neurites from cultured goldfish retinal ganglion cells.

Single retinal ganglion cells obtained from goldfish retina are shown to support outgrowth of neurites. Processes up to 1 mm in length grow out over a two week period from cells identified as retinal ganglion cells on the basis of morphological criteria, in the absence of supporting elements. Prior crush of the optic nerve significantly enhances neuritic outgrowth. Fibers emerging from single cells often associate to form a single process. A tendency for characteristic clockwise patterning of neurite outgrowth from single cells is seen, similar to that obtained from retinal explants.

Animals↗
PubMed1996

The amyloid precursor protein of Alzheimer's disease is found on the surface of static but not activity motile portions of neurites.

We have previously found that the amyloid precursor protein (APP) of Alzheimer's disease is present on the surface of rat cortical neurons in culture, in a segmental pattern which first becomes evident after 24 hours and is fully developed by five days. As APP has previously been reported to have a short half-life in neuronal cell lines, and has been shown to contain binding sites for various extracellular matrix components within its extracellular domain, we hypothesized that APP would be associated with portions of neurites undergoing rapid structural change, such as growth cones. To test this hypothesis, we observed selected neurons by video time-lapse differential interference microscopy on 24-hour-old primary rat neuronal cultures for up to 45 minutes, followed by fixation and immunocytochemistry to ascertain surface APP distribution on those same neurons. In contrast to our predictions, surface APP was not found on active portions of neurites, even if the activity produced no net translational movement. This result indicates that surface APP is actually associated with stable portions of neurites, a conclusion that tallies with other recent results showing that neuronal surface APP has a longer half-life than general cellular APP, and is associated with markers of adhesion patches, which themselves are relatively stable structures.

Amyloid beta-Protein Precursor↗
PubMed1986

In vitro studies of the golden hamster sperm acrosome reaction: completion on the zona pellucida and induction by homologous soluble zonae pellucidae.

We have studied the occurrence of the golden hamster sperm acrosome reaction (AR) in vitro during interaction with the oocyte investments: the cumulus cell matrix and the zona pellucida. Hamster sperm were capacitated in a defined medium that does not induce the AR. These spermatozoa were allowed to interact with the ovum vestments, the events of which were recorded using high-speed videomicrography. Frame-by-frame analysis revealed that sperm did not complete the AR in the cumulus cell matrix, but did so on the zona pellucida. Furthermore, a higher percentage of sperm completed the AR on the zona pellucida of cumulus-invested than on cumulus-free eggs. We also investigated the effect of solubilized hamster and mouse zonae pellucidae on the hamster sperm AR. Addition of solubilized hamster zonae to capacitated sperm elicited the AR within 15 min. Solubilized mouse zonae were significantly less effective, indicating that the zona-induced AR in hamster sperm may be species specific. These results suggest that the hamster zona pellucida is an inducer of the AR in the intact or soluble form, and that the majority of spermatozoa traverse the cumulus cell matrix without completing the AR in our in vitro system.

Acrosome↗
PubMed1988

Fc receptor-mediated binding and ingestion of immunoglobulin G-coated erythrocytes by the epithelium of the posterior ciliary processes: an in-vitro study.

In the present in vitro study of intact ciliary processes, we observed, under differential interference microscopy, IgG inhibitable selective epithelial adherence and internalization of IgG-coated erythrocytes (E-IgG). Unequivocal evidence of ligand ingestion was obtained with a fluorescence technique which employed glutaraldehyde-fixed opsonized erythrocytes. Neither adherence nor internalization were seen when uncoated erythrocytes, IgM, or F (ab')2-coated erythrocytes were substituted for E-IgG in the incubation media. These in-vitro studies demonstrated that the cell membranes of this epithelium exhibit a specific receptor for IgG which may clear the aqueous of IgG aggregates and be associated with the exocytosis of soluble mediators of inflammation.

Adhesiveness↗