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Biomedical subjects

W S Hwang

Publications and source records attributed to W S Hwang.

At least 109 records · Page 6Linked to original sources
PubMed1982

The significance of cytoplasmic chondrocyte inclusions in multiple osteochondromatosis, solitary osteochondromas, and chondrodysplasias.

Lesions from two patients with multiple osteochondromas and from three patients with solitary osteochondromas were studied. The histologic and ultrastructural features in both conditions were identical. The chondrocyte population in osteochondromas resembled those in normal hyaline cartilage but the cells in osteochondromas exhibited an accumulation of granular and filamentous materials within markedly dilated cisterns of ergastoplasm. These accumulations formed eosinophilic cytoplasmic inclusions which did not stain with Alcian blue, but were PAS positive after diastase digestion. Chondrocytic inclusions of similar or diverse morphology are found in a number of chondrodysplasias. The findings suggest that the solitary osteochondromas, like the lesions of multiple osteochondromatosis, share a common morphologic feature with the chondrodysplasias.

Cartilage↗
PubMed1982

Monophasic synovial sarcoma, epithelioid sarcoma and chordoid sarcoma: ultrastructural evidence for a common histogenesis, despite light microscopic diversity.

Ultrastructural examination of six rare sarcomas--four monophasic spindle cell tumours, one epithelioid sarcoma, one chordoid sarcoma--has revealed marked similarities at the electron microscopic level despite widely divergent light microscopic appearances. These features consisted of: 1 the presence of two cell types, viz. a clear cell and a cell resembling the fibroblast; 2 pseudoglandular spaces with projecting microvilli or filopodia, and with related tight junctions; 3 an amorphous intercellular ground substance with focal condensation into recognizable basement membrane. The findings suggest a common maturation of these diverse tumours to synovial-like tissue, and support the proposal of Hajdu Shiu & Fortner (1977) that these be considered variants of synovial sarcoma. Published ultrastructural studies of synovial, epithelioid and chordoid sarcoma are reviewed in the light of these findings. The ultrastructural differentiation of synovial sarcoma from extraskeletal myxoid chondrosarcoma, chordoma and the spectrum of malignant spindle cell tumours is discussed.

Adult↗
PubMed1982

Lamellar bodies in benign and malignant schwannomas.

A light and electron microscopic study was done on seven cases of schwannomas, four of which were benign and three were malignant. Spherical or oval cytoplasmic inclusion bodies, one to three microns in diameter, were detected in all cases. These inclusions were demonstrable by Luxol fast blue stain. Ultrastructurally, the inclusions appeared as whorls of cell membranes reminiscent of myelin sheath. These lamellar bodies probably reflect the peculiar membrane characteristics of Schwann cells, and they provide a useful marker for recognition of benign or malignant schwannomas.

Humans↗
PubMed1981

Malignant carcinoid tumor complicating chronic ulcerative colitis.

A case of malignant carcinoid tumor (neuroendocrine carcinoma) of the cecum is described. The neoplasm arose in a patient who had chronic ulcerative colitis for 16 years. There is no previous documentation of this combination, which is surprising, in view of the known association of colonic adenocarcinomas and lymphomas with ulcerative colitis. The reasons for this discrepancy are discussed and it is postulated that ultrastructural examination of poorly differentiated colonic neoplasms may result in a more frequent identification of this association.

Adult↗
PubMed1980

Congenital Torulopsis glabrata infection in man.

A case of congenital infection by Torulopsis glabrata in a premature 0.52-kg female infant born at 23 weeks' gestation to a 37-year-old, gravida 7 mother is reported. The infant succumbed to an intrauterine pneumonia and fungemia. Acute chorioamnionitis was present. Budding yeasts were found in the lungs and amniotic membranes and in large numbers within the lumen of the gut. The role of a retained intrauterine contraceptive device in predisposing to the ascending infection is discussed.

Adult↗
PubMed1979

The pathology of cartilage in chondrodysplasias.

The pathology of four types of chondrodysplasias, viz., type II achondrogenesis, thanatophoric dwarfism, Saldino-Noonan syndrome, and chondrodysplasia punctata were studied. In each of these disorders, cells with features similar to the chief and dark chondrocytes of normal hyaline cartilage were seen to be altered in different ways. There was a total absence of chief cells in type II achondrogenesis. All the chondrocytes present were of one variety at different states of maturation, with the fully matured cell having features of dark chondrocytes. The absence of chief cells was associated with marked diminution of interlacunar matrix and failure of growth plate development. The chief chondrocytes in thanatophoric dwarfism appeared diminished in number. They were probably abnormal functionally as evident by their lack of cytoplasmic vacuolation and the formation of thick, occasionally branched collagen in the matrix. The growth plate was stunted and poorly developed. Striking changes involving the dark cells were noted in Saldino-Noonan syndrome, where unusually elongated dark cells were found in groups within abnormal cystic spaces. The chief cells were large and contained abnormal cytoplasmic filaments. There was no formation of a growth plate. In chondrodysplasia punctata, the chief cells were enlarged and abnormally vacuolated. The matrix showed excessive aggregates of coarse granular material. In addition, there were focal accumulations of highly abnormal chief and dark cells with abnormal matrix which contained increased amount of keratan sulphate and culminated in spotty calcification.

Achondroplasia↗
PubMed1978

Ultrastructure of human foetal and neonatal hyaline cartilage.

Ultrastructural studies showed that human foetal and neonatal hyaline cartilage contained at least two types of chondrocytes. The predominant chondrocytes of chief cells were characterised by scanty, flat endoplasmic reticulum, few mitochondria, a rudimentary Golgi zone, and by the presence of clear cytoplasmic vacuoles which contained electron-dense granules and beaded filaments. The second type of cells had dark or electron-dense cytoplasm which contained numerous dilated endoplasmic reticulum and prominent Golgi zones; these cells gave rise to slender cytoplasmic processes from which the matrix vesicles were probably derived. The lacunar matrices surrounding both cell types were morphologically different reflecting some functional differences between these cells. Both types of cells participated in the formation of costochondral growth zones. Condrocytes with morphology of the chief cells proliferated, columnised, underwent hypertrophy, and differentiated either into a compact hypertrophic cell or a swollen pale cell. The cells also became hypertrophic and gave rise to increasing numbers of dense vesicles. Calcification was first noted in the longitudinal septa inside or adjacent to matrix vesicles. The recognition of the heterogeneity of chondrocytes in human hyaline cartilage may be helpful in understanding the pathology of the chondrodysplasias.

Cartilage↗
PubMed1976

Neonatal brain tissue embolism in the lung.

A brain tissue embolus was observed in a major pulmonary artery in the right lung, in a neonate who died from intracranial haemorhage 36 hours after delivery. This is the fifth documented case in a neonate and the only one in whom survival had occurred beyond one hour. Brain tissue emboli in the pulmonary circulation occur very rarely; it has been described in adults and children with head injuries. In newborn infants with severe congenital malformations of the central nervous system, brain tissue has been found growing in the lungs; the possibility of this being the result of prenatal brain trauma with embolization has been raised. In newborn infants, pulmonary brain tissue embolism as a result of birth trauma has been reported only very rarely; as far as the authors are aware, only four such cases have been documented. In view of the rarity of this condition, it was thought that the present case merited reporting.

Birth Injuries↗
PubMed1975

Xenogeneic red blood cell degradation in a regional lymph node and dissemination of antigens by circulating lymphocytes.

The degradation of intramuscularly injected autogenic and xenogenic red blood cells are studied with electron microscopy and immunoferritin technique. Autogenic red blood cells are phagocytosed and completely degradated by macrophages within the draining lymph node in a relatively short time. Phagocytosis and initial degradation of xenogeneic red blood cells by macrophages in the draining lymph node are similar; however, portions of the degradation products persist in macrophages as characteristic myelinic-like figures. After 4 days, identical figures appear in large numbers in the adjacent lymphocytes within membrane-bound vacuoles. With the conjugated ferritin antibody technique, these myelinic-like figures are shown to contain antigens of the xenogeneic red blood cells. Subsequently, lymphocytes containing the inclusions are found in the peripheral blood, the marginal zone of the spleen, other lymph nodes, and the bone marrow. As in the draining lymph node the number of plasma cells increases in these organs in areas adjacent to lymphocytes with the inclusions. In a parallel study, uncoated polystyrene spheres injected intramuscularly accumulate and remain localized in macrophages of the draining lymph node. When coated with xenogeneic hemoglobin and membranes, these spheres appear in lymphocytes of the draining lymph node and subsequently in lymphocytes of the blood and spleen.

Animals↗
PubMed1970

Cholelithiasis in Singapore. I. A necropsy study.

The present necropsy study shows an oriental pattern of gallstone disease in Singapore, namely, a relatively low overall frequency, an equal involvement of both sexes, a high proportion of pigment stones, and the common occurrence of choledocholithiasis associated with pyogenic cholangitis. There is a close association between opium addiction and cholelithiasis in the adult male Chinese in Singapore, and the long-term abuse of opium may be an important aetiological factor in the pathogenesis of oriental cholelithiasis.

Adult↗
PubMed1970

Cholelithiasis in Singapore. II. A clinical study.

In the present study of 241 patients submitted for gallbladder and biliary tract surgery, it is found that choledocholithiasis in cases in Singapore presents with a wide spectrum of clinical manifestations. It is essential that the less common clinical presentations should be recognized.

Adolescent↗