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Biomedical subjects

D Whitaker

Publications and source records attributed to D Whitaker.

At least 145 records · Page 8Linked to original sources
PubMed1982

Detection of tissue CEA-like substance as an aid in the differential diagnosis of malignant mesothelioma.

Sections of various adenocarcinomas and malignant mesotheliomas were tested for carcinoembryonic antigen (CEA) localized in tissues by the immunoperoxidase technique; epithelial mucin was demonstrated with the PAS technique. While CEA and mucin were found in many adenocarcinomas, both were absent in the 43 cases of malignant mesothelioma we investigated. In the problem of distinguishing between adenocarcinoma and mesothelioma, the CEA-test in combination with conventional strains for mucin is a useful technique and clearly identifies most adenocarcinomas. A dual negative result for CEA and mucin, although not proving that a given lesion is a mesothelioma, adds considerable support to this histological diagnosis.

Adenocarcinoma↗
PubMed1982

The mesothelium and its reactions: a review.

The origins, nature, and reactions of the mesothelium have intrigued investigators for over 100 years. Recently, the use of sophisticated techniques has clarified earlier impressions of its development, structure, and function. The structure of mesothelium reflects its functional properties, its long slender microvilli entrapping a layer of glycosoaminoglycans, providing a frictionless free surface between the parietal and visceral serosa. Transport requirements are met by various surface modifications and both inter- and intra-cellular mechanisms occur. The presence of stomatal openings in the mesothelial membrane has been established, and they may have a major role to play in the movement of cells to and from the serosal cavities. In addition, mesothelial cells can respond to situations of increased functional demand and during the course of inflammation, the mesothelium's fibrinolytic properties are of major importance in preventing the formation of adhesions and the enhancement of healing. Of all the unanswered questions the most significant is the nature, localization, and potentialities of mesothelial precursors. A mesodermal origin is readily acknowledged, but the healing process of damaged mesothelium is less clear. It seems probable that "mature" mesothelium is one source of cell renewal, but mesenchymal cells located in the submesothelial serosa are also strong contenders. Neoplastic mesothelium can adopt a spectrum of histological appearances, reflecting its mesodermal origins. In fact, overacceptance of this concept has erroneously led to the classification of other neoplasms arising in the serosal area as mesotheliomas. Although the ocogenic sequence is still obscure, asbestos is recognized as the major etiologic agent in malignant mesotheliomas. In 1955, Hartwell described differing impressions of the peritoneum as seen through the eyes of an anatomist, an histologist, and a surgeon. In this review on the mesothelium we have attempted to unravel some of its complexities as viewed by embryologists, electronmicroscopists, cell biologists, pathologists, and oncologists.

Biological Transport↗
PubMed1980

The mesothelium; techniques for investigating the origin, nature and behaviour of mesothelial cells.

To overcome some of the difficulties encountered in studying single layers of mesothelial cells, a battery of techniques was investigated, assessed, and modified. It was found that two main methods were of value: cell monolayers and surface sections. Imprint monolayers on slides coated with 3% gelatin were considered to provide the optimal imprint for cell kinetics and cytochemical assays at room temperature. On the other hand, slides coated with agar were more satisfactory for cytochemical techniques performed at 37 degrees C. The cell-deposit techniques were excellent for studying mesothelial cells in suspension. Investigation of cultured cells was best achieved by the use of a cell-mat on coverglasses for cytochemistry, while the base of the culture vessel with its own cell-mat monolayer was best for kinetic studies. This investigation demonstrated that maximum information is only gained by employing several different techniques. It also indicates which of these will be of greatest value in assessing any one particular aspect of mesothelial pathobiology.

Animals↗
PubMed1980

The mesothelium: a histochemical study of resting mesothelial cells.

Cytochemical investigations of the resting mesothelial cells of rats are reported. The study was performed on imprint monolayers obtained from various serosal surfaces by using 3% gelatin and 1% agar-coated microscopic slides. We found only a small amount of reaction product in mesothelial cells after cytochemical demonstration of those enzymes associated with oxidative respiration; however, abundant reaction product was found when the enzymes associated with the pentose phosphate path were sought. These findings suggest that this latter respiratory mechanism may play an active role in resting mesothelial cell respiration. Enzymes associated with cell membranes such as sodium and potassium dependent ATPase and 5' nucleotidase were readily found. The "resting" mesothelial cell also had demonstrable amounts of glycogen and RNA. It is concluded that despite the morphological suggestions that the resting mesothelium is not very active metabolically (Cascarano, 1964), its histochemical profile provides good evidence of a diverse range of functional and metabolic processes. The finding of similar cytochemical profiles, irrespective of the anatomical site of the mesothelial cell sample, is considered to give credence to the concept of the mesothelium as an entity.

Animals↗
PubMed1980

A case of filariasis diagnosed on gastric cytology.

Cytological examination of gastric washings or brushing is a widely accepted technique used as a diagnostic aid in the detection of gastric malignancy. Occasionally, cytology may also provide valuable information concerning a variety of non-neoplastic disorders. This brief report is of the exceptional experience of finding numerous microfilariae of Loa loa type in a gastric lavage specimen. This observation led to appropriate further investigation and successful treatment.

Cytodiagnosis↗
PubMedDate not supplied

Malignant mesothelioma cells in sputum.

In five patients with malignant mesothelioma of pleura, malignant cells, presumably derived from intrapulmonary deposits, were found in sputum specimens. The cells presented mainly as papillary aggregates of epithelial-like cells, in most cases without specific identifiable mesothelial cell features. In one patient, the specimen was received early in the diagnostic work-up and led to a strong consideration of the diagnosis of adenocarcinoma. In the remainder, the finding was incidental, occurring after the diagnosis of mesothelioma had been established. The cases are reported to draw attention to this phenomenon, previously unreported in the cytologic literature, and to emphasize that the finding of malignant cells in sputum does not preclude the diagnosis of malignant mesothelioma.

Aged↗
PubMedDate not supplied

Changes in macular function throughout adulthood.

Recent reports suggest that the neural system is the principal cause of loss of visual function with age and that senile lenticular and pupillary changes are of minor importance. In order to investigate this neural deterioration further we measured Logmar visual acuity and photostress recovery time (PSRT) in 61 subjects over an age range of 19 to 78 years. The magnitude of the PSRT reflects the efficiency with which the visual system recovers from exposure to a glare source and is principally dependent upon the integrity of the photoreceptors and the retinal pigment epithelium. The results indicate that macular function declines significantly throughout adulthood.

Adult↗
PubMedDate not supplied

Modelling of orientation discrimination across the visual field.

In many visual tasks thresholds can be made equal across the visual field by increasing the size of peripherally presented stimuli by appropriate magnification. The parameter E2 represents the eccentricity at which foveal stimulus size must double in order to maintain performance equivalent to that at the fovea. We measured orientation discrimination for a set of line sizes at various eccentricities. Thresholds were successfully scaled by applying a scaling function estimated by a technique that requires no prior assumptions regarding the size of peripherally presented stimuli. E2 of 1.95 deg was found for orientation discrimination. From our results we were able to develop a single equation which predicts orientation discrimination thresholds for an average observer over a range of different eccentricities and line lengths.

Discrimination, Psychological↗
PubMedDate not supplied

The role of cytology in the detection of malignant lymphoma of the uterine cervix.

The success of cytologic examination in the diagnosis of malignant lymphoma of the cervix is at present limited. The generally accepted cytologic criteria for the identification of malignant lymphoma may have to be applied with caution when examining material obtained by abrasive technique; the diagnosis should not be entirely excluded, even in the presence of cell aggregates.

Adult↗
PubMedDate not supplied

Cell aggregates in malignant mesothelioma.

The finding in cell block sections of a central core of collagen within tumour aggregates in 4 out of 12 cases of effusions due to malignant mesothelioma is statistically significant (P greater than .01) when compared with its incidence in 2 of 80 cases of effusion due to metastatic carcinoma. It is suggested that this observation may be of diagnostic value in the cytologic evaluation of effusions when malignant mesothelioma is suspected.

Ascitic Fluid↗
PubMedDate not supplied

The cytology of malignant mesothelioma in Western Australia.

The cytology of malignant mesothelioma seen in 12 patients associated with the mining of crocidolite asbestos in Western Australia is described. Two main patterns of mesothelioma were observed: the spindle cell and epithelial varieties. In the more common epithelial variety, five features were found to be of particular value in making a cytologic diagnosis. These include the finding of cell aggregates, multinucleation, the presence of brush-like borders, the close apposition of cell borders, and a characteristic cytoplasm. A diagnosis of malignant mesothelioma may be established by cytologic examination of effusions. The awareness of the possible occurrence of such a primary malignant neoplasm with the features outlined may be helpful in this regard.

Asbestos↗