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Biomedical subjects

F N Ghadially

Publications and source records attributed to F N Ghadially.

161 records · Page 9Linked to original sources
PubMedDate not supplied

As You Like It, Part 2: A critique and historical review of the electron microscopy literature.

As You Like It, Part 2, is a continuation of the lecture given at UltraPath VIII in 1996. It is meant to be a critical historical review of some topics of interest to electron microscopists that will show what went wrong and perhaps also why. Topics are presented under the following headings : (1) Amianthoid Fibers and Giant Collagen Fibrils, (2) Ribosome-Lamella Complex, (3) Globular Filamentous Bodies, and (4) Siderosomes, Hemosiderin vs. Ferritin.

Collagen↗
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Overview article: the articular territory of the reticuloendothelial system.

It has long been recognized that synovial intimal cells are phagocytic and that they are capable of picking up colloidal or particulate material injected into the circulation. Hence they have been described as the "articular territory of the reticuloendothelial system." Ultrastructural studies have added a wealth new knowledge and details about the remarkable endocytotic powers of synovial cells. It has been shown that they can endocytose not only small particulate substances like colloidal iron, colloidal gold, and thorotrast but also relatively large objects like masses of fibrin and entire erythrocytes. Controversy has arisen as to whether it is the Type A or Type B cell that is the main scavenger of the joint. Evidence will be presented to show that this is a somewhat fictitious controversy and that these are not distinct and different races of cells with different functions but merely cells whose differences in morphology reflects the function they are performing at a given moment.

Animals↗
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Diagnostic value of some matrix components.

Although most diagnostic markers lie within the cell, a few are found in the matrix. Well-known examples of these are amyloid filaments and fibrous long-spacing collagen (Luse body). Perhaps not so well-known are the diagnostic values of anchoring fibrils and microvillus-matrix associations. The latter two form the subject of this paper.

Adenocarcinoma↗
PubMedDate not supplied

Intracisternal collagen fibrils in proliferative fasciitis and myositis of childhood.

During ultrastructural examination of a difficult to diagnose tumor, short spacing collagen fibrils (periodicity of banding, approximately 43.2 nm) and native collagen fibrils (periodicity of banding, approximately 53 nm) were found in dilated and vacuolated cisternae of rough endoplasmic reticulum and the perinuclear cistern. Original diagnoses from several histopathologists included alveolar soft part sarcoma, malignant fibrous histiocytoma, atypical fibroxanthoma, and myogenic tumor. The finding of intracisternal collagen (which is but a variety of intracellular collagen) led to the conclusion that this was a fibroblastic neoplasm. This, plus a review of the histologic findings, led to the diagnosis of proliferative fasciitis and myositis of childhood.

Adolescent↗
PubMedDate not supplied

Giant desmosomes in tumors.

The lengths of desmosomal profiles were measured in sections of tumor tissue from cases of mesothelioma, adenocarcinoma, squamous cell carcinoma, thymoma, and meningioma. Giant desmosomes (length of profile 1 micron or greater than 1 micron) were found in all the above-mentioned tumors except adenocarcinomas. The largest desmosomal profile in adenocarcinoma was approximately 0.8 micron long; the largest in mesothelioma was approximately 2 microns long. Our observations suggest that one of the ways in which giant desmosomes arise is by growth and fusion of adjacent desmosomes. Giant desmosomes may at times help in distinguishing mesothelioma from adenocarcinoma, but this is a rather rare phenomenon. In this study giant desmosomes were found in only 2 out of 10 cases of mesothelioma.

Adenocarcinoma↗
PubMedDate not supplied

Pigments of the gastrointestinal tract: a comparison of light microscopic and electron microscopic findings.

It is now apparent that light microscopy and histochemistry failed to identify correctly the nature and composition of pigments in various gastrointestinal tract melanoses. In most instances it was thought that the pigment was melanin or a melanin-like substance. Electron microscopy (EM) and electron-probe energy dispersive x-ray analysis have rectified these errors and have shown the following: in melanosis coli the pigment granules contain lipofuscin; in melanoses ilei the pigment granules may contain either silicates and titanium or hemosiderin; and in melanosis duodeni the pigment granules contain iron sulfide. In melanosis esophagi it is not clear what the pigment is; it could be melanin or lipofuscin.

Digestive System↗
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Globular smooth-tubule aggregates in thanatophoric dwarfs.

A presumably new structure that we have called "globular smooth-tubule aggregate" was found in the cytoplasm of chondrocytes of 4 thanatophoric dwarfs. To the best of our knowledge these sharply delineated, rounded, sieve-like bodies of distinctive morphology have not been reported to occur in any other site or situation. Hence these structures may be of some diagnostic value. Continuity between the rough endoplasmic reticulum and smooth tubules in the aggregates was detected. Therefore it is suggested that smooth tubules in these aggregates derive by growth and extension from the rough endoplasmic reticulum.

Cartilage↗
PubMedDate not supplied

As you like it.

I have developed something of a reputation for criticizing freely and frequently at our meetings and in my writings. You say you like this and find it useful and entertaining. As you like it, you are welcome to more of it. My comments and criticisms are presented under the following headings: (1) criticize at your peril; (2) how it all started (unjustly accused!); (3) abbreviations (a source of perennial aggravation, confusion, and waste of time); (4) mysterious bodies in mesotheliomas; (5) call a crystal a "crystal," not a "crystalloid"; (6) electron microscopy-a study of osmium artifacts; (7) length-to-diameter ratio of microvilli (mission impossible); (8) lamellar bodies (a popular but debased term); (9) amyloid filaments, not fibers; (10) filaments and microtubules do not branch; (11) there is no such thing as pseudomelanosis; (12) botched histochemistry (just about every gastrointestinal tract pigment was misdiagnosed by histochemistry); (13) intranuclear Russell bodies, not "Dutcher bodies"; and (14) nuclear pores and virus-like particles (a new development in an old farce).

Abbreviations as Topic↗
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Melanosis thyroidi.

Despite many studies on melanosis thyroidi, there is no consensus concerning the nature of the pigment or its pathogenesis. Here the past literature on this subject is reviewed and results are reported on a case of melanosis thyroidi that provides fresh insight into the nature of the pigment and its genesis. Briefly, the conclusion is that while a few of the pigment granules are classic lipofuscin granules (i.e., single-membrane-bound structures containing electron-dense material in the form of particles, granules and masses, and electron-lucent lipid droplets), a majority of the pigment granules also contain colloid, which is easily identified by its particulate substructure similar to the colloid in the lumen of follicles. Thus, these pigment granules are, in fact, ambilysosomes, where degradation of both endogenous (organelles) and exogenous (colloid) material occurs. Several phagosomes containing colloid were also seen in the thyroid epithelial cells.

Aged↗
PubMedDate not supplied

The role of electron microscopy in the determination of tumour histogenesis.

In the majority of cases the histogenesis and classification of tumours can be unequivocally established by light microscopy, but in some instances the diagnosis remains ambiguous even after special staining techniques have been employed. So wide and varied are the situations in which the electron microscope can help establish a diagnosis that it is impossible to even mention them all in the brief time available. I will therefore present only a brief description of the manner in which one can resolve with the electron microscopy some well known diagnostic problems. This includes distinguishing: (1) an anaplastic carcinoma from a sarcoma; (2) an amelanotic melanoma from other tumours; (3) APUDomas from other tumors; (4) myosarcomas from other tumours; and (5) Ewing's tumour, neuroblastoma and lymphoma from each other.

Adenocarcinoma↗