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Results for “MICROSCOPY, PHASE CONTRAST”

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At least 181 records · Page 10Linked to original sources
PubMed1993

Phase contrast microscopy for identifying epidermal margins in unstained cryosections for Mohs micrographic surgery.

BACKGROUND: Mohs fresh tissue micrographic surgery has been accepted as the most reliable therapeutic modality for the eradication of recurrent cutaneous malignancies or those skin cancers that are difficult to treat otherwise. OBJECTIVE: We have developed a method to ascertain the presence of the epidermis and other edges in the tissue sections before staining the cryosections and microscopically searching them for cancer cells. METHODS: Our method for screening the cryosections for the epidermis can be done quickly and easily using relatively inexpensive phase contrast optics. RESULTS: Use of this method allows easy visualization of freshly cut cryosections, especially the presence of the epidermis and other edges of the tissue, in just a matter of seconds instead of a half hour to stain and recut the sections. CONCLUSIONS: Phase contrast microscopy and/or dark field illumination are instrumental in screening unstained cryosections for the presence of the tissue borders, especially the epidermis, before they are stained with hematoxylin and eosin. This method saves a great deal of time and effort both for the surgeon and the patient.

Epidermis↗
PubMed1983

Phase contrast microscopy of microbial aggregates in the gingival sulcus of Macaca mulatta. Subgingival plaque bacteria in macaca mulatta.

The objective of this study was to study the relationship of microbial aggregates in the subgingival crevice to changes in periodontal health in Macaca mulatta. The sample included 68 oral sites from 17 Rhesus monkeys of various ages. The periodontal health of each site was evaluated using Plaque and Gingival Indices and crevice depth measurement. The subgingival plaque samples were examined by phase contrast microscopy and recorded on 16 mm film. A Microbial Index was developed based on a qualitative estimate of the numbers of organisms, morphology of predominant organisms, and the presence or absence of motility. The Microbial Index was demonstrated to be simple in use and highly reproducible. The findings indicate that changes in the Microbial Index are consistent with tissue changes seen in the periodontal status in M. mulatta. From this preliminary study, the oral flora of adult M. mulatta appears to have sufficient similarities to human oral flora to be used as a microbial model for experimental periodontal disease research. Future studies to refine and confirm the validity of the Microbial Index are warranted. It may prove to be a useful tool to monitor the effect of various treatment modalities on the periodontal flora and to determine the presence or absence of active disease.

Animals↗
PubMed2001

Validity of wet-mount bacterial morphotype identification of vaginal fluid by phase-contrast microscopy for diagnosis of bacterial vaginosis in family practice.

The aim of this study was to determine the accuracy of a wet-mount bacterial morphology scoring (BMS) system and Nugent's Gram stain analysis for the diagnosis of bacterial vaginosis, using Amsel's criteria as the gold standard. The three diagnostic criteria were assessed independently The BMS diagnosis was based on a scoring system which weighed the number of small bacterial morphotypes regarded as typical of bacterial vaginosis against lactobacillary morphotypes in phase-contrast microscopy of wet-mount preparations. Three groups of non-pregnant women attending either because of vaginal discharge, other genitourinary symptoms, or for a routine check-up, and a group of pregnant women attending for antenatal care were studied. The diagnostic accuracy was measured by sensitivity, specificity, positive and negative predictive values, and likelihood ratio. The accuracy of the BMS diagnosis was substantially high in all of the examined groups (LR 15.4-20.3). The accuracy of the Gram stain diagnosis was lower (LR 7.6-10.9). In the total material, the accuracy of the BMS diagnosis was higher than that of the Nugent's Gram staining. Intra- and inter-observer reproducibility of all three criteria applied was high. We propose greater routine use of the new BMS diagnosis for point-of-care testing in family practice as well as in research and in microbiology laboratories.

Adult↗