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At least 793 records · Page 44Linked to original sources
PubMed1978

The prognostic and therapeutic value of frozen section determinations in the surgical treatment of squamous carcinoma of the head and neck.

The records of 216 patients with squamous cell carcinoma of the oral cavity, oropharynx, and hypopharynx treated by surgery alone were reviewed. Frozen section control at the time of the surgical procedure was used to evaluate the margins of the excision. Findings at frozen section were correlated with local control and survival. The inability of the surgeon to obtain clear margins by frozen section for whatever reason resulted in a very high incidence of local recurrence and death. The fact that the patient's tumor could be removed with free margins at the time of surgery did not guarantee long-term success, although the frozen section technic did prove to be reliable and an effective tool for evaluating the patient's prognosis and the efficacy of the surgical procedure.

Carcinoma, Squamous Cell↗
PubMed1986

Microscopic cut-through of cancer in the surgical treatment of squamous carcinoma of the tongue. Prognostic and therapeutic implications.

A retrospective review was carried out of the records of 268 patients with a pathologically proved diagnosis of squamous carcinoma of the tongue treated by glossectomy at M.D. Anderson Hospital and Tumor Institute from January 1, 1970 through December 31, 1979. Pathologic findings found on frozen section analysis were correlated with the TNM stage of the tumor, histologic characteristics, perineural invasion, type of treatment, local recurrence, and survival rate. Thirty-eight patients with squamous carcinoma of the oral tongue and 16 patients with tumors of the base of the tongue had initially positive frozen section margins. Forty-one of these patients had margins that were negative at the completion of surgery. Thirteen patients never had negative margins. Positive mucosal margins were more common in smaller tumors and positive muscular margins were more common in larger tumors. Patients with perineural invasion and larger tumors had a higher percentage of positive margins. Those patients with initially positive margins that were rendered negative at the completion of the procedure and treated with surgery only had a significantly increased local recurrence rate and reduced survival compared with patients similarly treated with initially negative margins. Tumor stage, location (muscular versus mucosal) of positive margins, and the presence of perineural invasion were not significant in predicting local recurrence or decreased survival. If all patients with microscopically positive margins are considered for postoperative radiotherapy, then the routine use of intraoperative frozen section examination of the margins of resection in squamous carcinoma of the tongue may not be justified.

Carcinoma, Squamous Cell↗
PubMed1990

The uptake of water by freeze-dried human dentine sections.

Ten sections of dentine, cut perpendicular to the dentinal tubules, from human mature non-carious third molars were freeze-dried and then rehydrated by immersion in water. The uptake of water by the sections was determined as a function of time by weighing. Rehydration was complete. On the basis of 3 theoretical models the uptake could be described by a combination of the capillary suction of water into the dentinal tubules and the diffusion of water into the mineralized matrix parallel to the tubules. The calculated diffusion coefficient describing the diffusion of water into the intertubular dentine was 1.74 (+/- 0.42) x 10(-10) m2/s. (mean +/- SEM, n = 10). A further calculation found that 75.2 (+/- 1.5)% of the water is in the tubules and thus 24.8 (+/- 1.5)% is in the mineralized matrix.

Dentin↗
PubMed1993

Serial variation in histological character of articular soft tissue in young human adult temporomandibular joint condyles.

Histological variation was studied in serial sections, in contrast to previous studies which have generalized from representative sections. The sample consisted of consecutive serial sagittal sections from the central third of nine condyles, plus an accompanying stone cast showing the intact articular surface before sectioning. The thickness of the articular soft tissue and its fibrous connective tissue and cartilage components was measured, and the presence of undifferentiated mesenchymal (UM) cells was assessed by low-power light microscopy. Components of variance analysis showed that section-to-section variation in thickness was of the same order as differences between joints, each explaining approx. 50% of the variance in both connective tissue and cartilage thickness. The fibrous connective tissue contributed as much to the overall variation in soft tissue thickness as did the cartilage component (SD 0.0946 versus 0.0909 mm for the superior sector). Serial UM cell variability was common, and the UM cells were often distributed in islands rather than uniformly across the articular tissue. Condyles with the greatest surface irregularity were characterized by greater serial variability in fibrous connective tissue thickness, more frequent absence of cartilage, and more areas of UM cell depletion. These results suggest that serial variation in histological character may be more important than mean values in the description of surface contours and articular tissue relations in the temporomandibular joint. This should influence the design of future investigations.

Adult↗
PubMed1995

The effects of sectioning angle on measurements of enamel prism size and spacing.

Comparative studies of prism size and spacing employ variables that are based on idealized, two-dimensional models. Results of modelling experiments illustrate that three-dimensional prism orientation can have a significant impact on two-dimensional measurements. In comparing prism size and spacing variables, it is essential to maintain control over the angle at which prisms are sectioned in order to compare real differences between taxa rather than preparation artefact. The further sectioning angles are from orthogonal, the greater the possibility for misrepresenting true prism size and spacing. While the survey of prism compression/extension (k) values reported here, as well as those described in previous studies, indicate that prism sectioning angles are only rarely extreme enough to render other values of prism and ameloblast size and spacing useless, the potential influence of sectioning obliquity on variation cannot be dismissed.

Ameloblasts↗
PubMed1992

Evidence that the loss of rat liver cytochrome P450 in vitro is not solely associated with the use of collagenase, the loss of cell-cell contacts and/or the absence of an extracellular matrix.

Two methods avoiding the widespread technique of collagenase perfusion have been employed to study the regulation of total cytochrome P450 content in rat hepatocyte culture. One technique required the perfusion of the liver with the chelating agent EDTA to dissociate the parenchymal cells prior to culture. Over a period of 48 hr, cultured hepatocytes isolated by EDTA perfusion showed comparable losses of cytochrome P450 as cells isolated by perfusion with collagenase. The second technique involved the culture of 210-240 microns thick "precision cut" liver slices. The results presented here indicate that the liver slices remain viable for 24 hr of culture, but that liver slices also lose their cytochrome P450 content at a comparable rate to collagenase prepared cells in culture. Collectively the results suggest that there is not a direct causal relationship between the loss of cytochrome P450 and one or a combination of the use of collagenase; the loss of cell-cell contacts and the absence of an extracellular matrix.

Animals↗