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Biomedical subjects

T M Mukherjee

Publications and source records attributed to T M Mukherjee.

At least 37 records · Page 2Linked to original sources
PubMed1983

The role of electron microscopy and microanalytical techniques in the understanding of the pathophysiology of environmental dusts associated with lung disease.

The purpose of this study has been to elucidate the usefulness of TEM/STEM/EDX system in the identification of environmental dust within the interstitial macrophages of the lung. The four cases chosen for this study gave variable history of exposure to occupational "dust". A review of literature with particular reference to clay associated pneumoconiosis has been made. Previous studies have given little prominence to the fate or behaviour of inhaled "dust" particles in the intracellular environment. It is here that it is believed that a TEM/STEM/EDX system has the potential of playing a significant role in promoting our understanding of "dust" associated pneumoconiotic disease of the lung. The results obtained from the three cases demonstrate the presence of clay particles in the form of granules, plates and needles or thin flakes within the phagosomes of the interstitial macrophages. On morphological grounds the thin needles or flakes appeared to undergo a process of stacking within the phagosomal matrix resulting in the formation of large closely stacked needle-like structures which lie free in the cytoplasm. The possibility of a physicochemical basis for such a morphological sequence is discussed. The fourth case, that of stainless steel associated pneumoconiosis, also showed evidence of breakdown of the original dust in the macrophages. From the evidence presented it is concluded that application of the TEM/STEM/EDX technique may advance our knowledge of the interaction of inhaled dust and the macrophages at the subcellular level.

Adult↗
PubMed1983

Scope of scanning electron microscopy, transmission electron microscopy and freeze fracture technique in diagnostic cytology of effusions.

A review of the literature on the application of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to cytodiagnosis of neoplastic cells in effusion fluid reveals a lack of consensus as to which of the techniques is most beneficial to a cytologist for a satisfactory diagnosis. The purpose of this study is therefore to critically evaluate the relative merits of SEM, TEM and freeze-fracture (FF) techniques in enhancing the diagnostic "sensitivity" of ultrastructural cytology. Two cases of adenocarcinoma, one case of mesothelioma and one case of small cell undifferentiated carcinoma of the lung were studied in detail by SEM, TEM and FF techniques. A comparative analysis of the results demonstrates that SEM is a rapid and useful technique where the microvilli on the tumour cell surface is the most prominent feature especially in adenocarcinomas. The major handicap of SEM becomes evident in cases where the extreme variability of the surface morphology amongst tumour cells makes it difficult to establish a diagnosis with confidence. TEM along with light microscopy (LM) of toluidine blue sections gives us the most comprehensive method for cyto-diagnosis and is particularly useful in cases where LM cytology alone is inconclusive. It has the added advantage of revealing diagnostically significant nuclear and cytoplasmic features which are helpful in differentiating a benign from a malignant cell and in some instances the probable site of the primary neoplasm. FF technique, though not conducive to a routine diagnostic situation, is of benefit in demonstrating the organization of junctional complexes. From preliminary studies it appears that the tight junctions in adenocarcinoma are different from those seen in small cell carcinoma. In mesothelioma, gap junctions are invariably present, but they are not seen prominently in adenocarcinoma or small cell carcinoma. Thus in poorly differentiated tumours where LM and TEM are inconclusive, FF may prove useful. It is concluded that such coordinated studies in the future have the potential to better our understanding of the nature and behaviour of tumour cells in effusion fluid.

Adenocarcinoma↗
PubMed1982

The structure of tight junctions between uterine luminal epithelial cells at different stages of pregnancy in the rat.

The ultrastructure of tight junctions between uterine luminal epithelial cells of the pregnant rat was studied by the freeze-fracture technique. On day 5 of pregnancy, the day of implantation, the region of tight junctions extended three times as far down the lateral cell membrane as on day 1 of pregnancy, and the strands of the complex interlinked more frequently. These observations suggest that tight junctions on day 5 may be more efficient in preserving the contents of the uterine lumen from dilution or escape than at earlier times of pregnancy.

Animals↗
PubMed1982

Reflexive gap junctions on uterine luminal epithelial cells.

Freeze-fracture electron microscopy has been used to search for reflexive gap junctions on apical projections of uterine epithelial cells in the rat. These structures were found in 5 of 6 animals in the study and consisted of from 15 to over 70 intramembranous particles which ranged in size from 7 to 9 nm. Some suggestions on the function of these enigmatic junctions are discussed.

Animals↗
PubMed1982

Changes in the fine structure of the apical plasma membrane of endometrial epithelial cells during implantation in the rat.

In previous work we have shown that ovarian hormones, when injected into ovariectomized rats, alter the fine structure of the plasma membrane of endometrial epithelial cells. In this paper freeze-fractures have been used to study the apical plasma membrane of endometrial epithelial cells of rats during the period of blastocyst implantation of normal pregnancy. On day 1 of pregnancy there were 2354 +/- 114 intramembranous particles (IMPs) per micrometer2 of membrane. The particles were spherical and randomly distributed. On day 5 of pregnancy IMP density rose to 2899 +/- 289 per micrometer2 and some rod-shaped particles were also visible. By day 6 of pregnancy IMP density had risen to 4014 +/- 206 per micrometer2 and there were more rod-shaped IMPs than before. In addition, on day 6 IMPs were also present as rows of particles and some gap-junction-like arrays of particles were also seen. Our findings indicate that there are fine-structural alterations in the apical plasma membrane of endometrial epithelial cells, the site of first contact between maternal and embryonic cells, during the period of early pregnancy. The findings are discussed in the light of suggested mechanisms of blastocyst attachment to the uterine epithelium at implantation.

Animals↗
PubMed1982

Ultrastructure and electron-probe x-ray analysis of the pigment in melanosis duodeni.

A patient with peptic ulceration developed melanosis duodeni, which was studied by light microscopy, histochemistry, electron microscopy and electron-probe x-ray analysis. Our studies show that the pigment in melanosis duodeni resides in the lysosomes of macrophages in the lamina propria. The pigment is not melanin or a melanin-like compound as has been claimed by previous workers. On the basis of electron-probe x-ray analytical findings we have concluded that the pigment is essentially FeS. On the basis of the history of this patient and cases reported in the literature we think that the Fe in this pigment is derived from haemorrhage in the gastrointestinal tract. We also found small amounts of Ca, K, Al, Mg, Si, and Ag. It would appear that Al, Mg and Si were probably derived from the biological milieu and/or other drugs and/or food and/or specimen contamination.

Cytoplasmic Granules↗
PubMed1981

Effects of ovarian hormones on cell membranes in the rat uterus. II. Freeze-fracture studies on tight junctions of the lateral plasma membrane of the luminal epithelium.

Freeze-fracture techniques have been used to study tight junctions on the lateral plasma membrane of cells of the luminal epithelium of the rat uterus under various hormonal regimes. Tight junctions from ovariectomized control rats extended some 0.5 micron down the lateral membrane and the junctional strands often formed a network of closely packed, circular compartments. Following treatment of rats with estrogen for 3 days the tight junctional region still extended 0.5 micron down the lateral membrane, but the strands ran more parallel to the apical surface. They did not enclose circular compartments. After treatment with progesterone, either alone or with estrogen in such a way as to condition the ovariectomized uterus for implantation, a third pattern of junctional organization emerged. In these animals the junctional region extended 1.1 micron down the lateral membrane and the strands frequently crosslinked, enclosing compartments of varying and irregular size and shape. Our observations suggest that ovarian hormones could regulate the contents of the uterine lumen by altering the structure and extent of the tight junctions which connect the epithelial cells enclosing the lumen.

Animals↗
PubMed1979

Effects of ovarian hormones on cell membranes in the rat uterus. I. Freeze fracture studies of the apical membrane of the liminal epithelium.

Freeze fracture techniques have been used to study the apical membrane of cells of the luminal epithelium of the rat uterus under various hormonal regimes. In the ovariectomized but otherwise untreated rat, intramembranous particles (IMPs) occur at a density of 1395 +/- 122 per micron 2; they appeared spherical and uniformly distributed. After 3 days treatment with estrogen, no change in appearance or density was found, but 3 days of progesterone treatment produced a significant increase in IMP density to 1622 +/- 104. Treatment with progesterone, with an additional dose of estrogen on day 3, is known to produce an epithelium receptive to the implanting blastocyst. In these conditions, the IMP density rose to 3818 +/- 337: rod-shaped particles and aggregations of IMPs were seen, and some particle arrays resembling gap junctions, in addition to the isolated spherical particles.

Animals↗
PubMed1978

Membrane changes associated with mucus production by intestinal goblet cells.

Changes in the structural organization of membranes of mucous bodies and the plasma membrane that occur during mucus production in goblet cells of rat rectum have been studied by thin-section and freeze-fracture techniques. Immature mucous bodies are bounded by a trilaminar membrane and fracture faces of the membrane have randomly distributed intramembrane particles. During maturation, mucous bodies become packed tightly together and changes in the structure of their membranes include (1) fusion of apposing membranes of adjacent bodies to form a pentalaminar structure, (2) a reduction in the density of particles on membrane fracture faces, and (3) exclusion of particles from regions of membrane apposition. Some trilaminar membranes of mucous bodies fuse with the lumenal plasma membrane to form a pentalaminar structure. Sites of apposition between mucous body membranes and the lumenal plasma membrane are seen as particle-cleared bulges on fracture faces of the plasma membrane. Our results indicate that membrane reorganization associated with mucous production in goblet cells includes a reduction and redistribution of some membrane proteins and that membrane fusion occurs between portions of membranes from which proteins have been displaced.

Animals↗
PubMed1977

Hypertension due to a renin-secreting tumour localised by segmental renal vein sampling.

An 18-year-old female was found to be hypertensive on routine medical examination. Further investigation disclosed persistent hypokalaemia and elevated plasma renin activity in peripheral venous blood. Segmental renal vein sampling with assay of blood samples located the source of excess renin secretion in the lower mid-zone of the left kidney. This localization was not confirmed by either angiography or by palpation of the exposed kidney before nephrectomy but macroscopic examination of the freshly sectioned kidney revealed a small tumour in the region suggested by renal vein sampling. The tumour had the morphologic pattern fo an haemangiopericytoma with abundant ultrastructural specific granules and very high renin activity by tissue assay. Plasma renin activity fell precipitously after nephrectomy and remained very low for the first week. Although the immediate post-operative blood pressure fell to normal, hypertension recurred temporarily and was associated with elevated plasma aldosteron, producing a syndrome similar to primary aldosteronism. All variables returned to normal without specific therapy and hypertension has not subsequently recurred.

Adolescent↗
PubMed1977

C bodies and R bodies in the epithelial cells of normal and diseased human rectum.

Small spherical, extracellular bodies (C bodies) measuring 20 to 80 nm in diameter and enclosed by a trilaminar membrane 7 nm wide surrounded the microvilli of human rectal epithelial cells. Similar bodies were observed within membrane-bound vesicles (R bodies) in the apical cytoplasm. The C bodies associated with the mature epithelial cells of the luminal surface were more numerous than those associated with the immature cells of the crypts, where the R bodies predominated. A decreased number of C bodies was observed in ulcerative colitis. We concluded that the membrane-bound C bodies surrounding the microvilli were cellular in origin and arose from R bodies within the cytoplasm of the rectal epithelial cells.

Cell Membrane↗
PubMed1972

Quantitative variations in the disposition of the enteric surface coat in mouse jejunum.

Utilizing colloidal iron staining to localize acid mucosubstances both at light and electron microscopic levels it has been observed that, in the strain of mice studied, there is a distinct variation in the cell-to-cell disposition of the so-called ;glycocalyx', ie, the enteric surface coat. It has been inferred that this glycoprotein surface coat is not-analogous to lubricious mucous secretion-a uniform smearing of the epithelial cells by goblet cell mucus. It is also found that each cell possesses and synthesizes its own individual surface coat, with some cells exhibiting more, others less, and still others deficient in surface coat at a given time. It is suggested that these observed variations could well reflect the maturity and functional state of the absorptive cells.

Animals↗