Search PubMed⌕ Search

Biomedical subjects

G C Yang

Publications and source records attributed to G C Yang.

At least 37 records · Page 2Linked to original sources
PubMed1997

Effect of ultrafast Papanicolaou staining on nuclear and textural features in breast cancer cytology.

OBJECTIVE: To compare quantifiable cytologic features of mammary lesions prepared using the Ultrafast Papanicolaou, Diff-Quik and Papanicolaou methods. STUDY DESIGN: Thirteen patients with mammary lesions were studied; the majority had histopathologic diagnoses of infiltrating ductal carcinoma. For each patient, three specimens were prepared, using (1) Diff-Quik staining after air drying, (2) Papanicolaou staining after wet fixation, and (3) the Ultrafast Papanicolaou procedure. Descriptors of nuclear size, shape and texture were computed from an average of 61.9 normalized nuclear images per specimen. Differences between preparation methods were analyzed using two-way analysis of variance. RESULTS: While differences in nuclear size, shape and texture existed between the three cytologic staining methods, only form factor varied significantly between conventional and Ultrafast Papanicolaou stain. Nuclear areas were larger in Ultrafast Papanicolaou specimens than conventional Papanicolaou specimens, but this difference was not statistically significant. CONCLUSION: The Ultrafast Papanicolaou procedure improves on conventional Papanicolaou staining in terms of speed, with no important quantifiable differences in nuclear morphology.

Analysis of Variance↗
PubMed1996

Morphogenesis of inclusion bodies of urothelial carcinoma: a case study.

The morphogenesis of inclusions of urothelial carcinoma (K. Donhuijsen et al.: Hum Pathol 23:860, 1992) is described in a case of a 51-year-old man with poorly differentiated urothelial carcinoma. Peritoneal fluid preparations contained numerous dyscohesive, large, anaplastic cells with abundant dense amphophilic cytoplasm often compartmentalized into multiple, variably sized, intracytoplasmic lumina, each containing "bull's eye"-like inclusions, with a periodic acid Schiff-positive refractile central core and an alcian blue/mucicarmine-positive rim. Ultrastructurally, the progression of osmiophilic substance from membrane-bound exocrine-type secretory granules, via exocytosis, to a presence in both intracytoplasmic lumina and extracellular space has been documented. Immunohistochemically, the periodic acid Schiff-positive refractile cores, as well as the minute periodic acid Schiff-positive granules in the cytoplasm, stained positively for secretory component and peanut agglutinins, whereas the alcian blue-positive mucinous material, which coated the refractile cores as well as the lining of the intracytoplasmic lumina, stained strongly for epithelial membrane antigen and leu M1. Ultrastructurally, protein A-gold probes, immunolabeled for peanut agglutinin and secretory component, were localized to the osmiophilic substance.

Carcinoma, Transitional Cell↗
PubMed1995

Ultrafast Papanicolaou stain is not limited to rapid assessments: application to permanent fine-needle aspiration smears.

Ultrafast Papanicolaou (Pap) stain, a 90-second preparation originally designed for the immediate assessment of fine-needle aspiration (FNA) smears (Yang and Alvarez, Acta Cytol 1995;39:55-60), can also be adapted for permanent FNA smears. It involves the addition of three simple steps prior to the conventional Pap procedure: the first step is to make the cells appear larger, thus increasing the resolution for analysis of cellular details; the second step is to hemolyse the background blood, thus unmasking tumor cells; and the third step is to bring out the vibrant colors in the cells and the nucleoli, which stain red.

Adenocarcinoma↗
PubMed1995

Mucinous adenocarcinoma of the endometrium with intestinal differentiation: a case report.

Mucinous differentiation of endocervical type has been well documented in endometrial carcinoma. However, we describe an unusual case of adenocarcinoma of the endometrium showing diffuse histological, immunohistochemical, and ultrastructural evidence of intestinal differentiation. Although intestinal differentiation has been described in mesodermally derived tissues including endocervix, ovary, and urinary tract, it has not been reported in normal endometrium. One previous case has been reported showing this pattern in endometrial carcinoma. Possible histogenetic mechanisms of this pattern are discussed.

Adenocarcinoma, Mucinous↗
PubMed1994

Major lectin of alligator liver is specific for mannose/L-fucose.

We surveyed the calcium-requiring (C-type) lectins in alligator liver. The major lectin purified by affinity chromatography was termed alligator hepatic lectin (AHL) and was found to be specific for mannose/L-fucose. AHL contained approximately equal amounts of 21- and 23-kDa bands upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Binding characteristics of AHL were similar to those of hepatic lectins of other classes in that 1) only terminal monosaccharide was recognized, and 2) the affinity increased exponentially when neoglycoproteins containing increasing numbers of mannose or L-fucose were used as ligand. However, unlike mammalian and chicken hepatic lectins, which exist as hexamers in Triton-containing solutions, AHL was present mainly as monomers, although small amounts of dimer and higher oligomers were present in equilibrium. Mannose-binding proteins and mannose-specific lectins of macrophages bind N-acetylmannosamine, glucose, and N-acetylglucosamine in addition to mannose, indicating that the nature and orientation of the C-2 substituent are not important to these lectins. In contrast, AHL shows a strict requirement for the presence of an axial hydroxyl group at the C-2 position (i.e. mannose).

Alligators and Crocodiles↗
PubMed1994

Demonstration of fibrils in the hyaline globules of yolk sac tumor with parietal differentiation in fine-needle aspiration smears.

Hyaline globules of the yolk sac tumor (YST) have been described as homogeneous pink intracellular globules and intercellular basement membrane material [Akhtar et al.: Diagn Cytopathol 1990:6:184-192]. In Diff-Quik-stained air-dried smears of a lung fine-needle aspiration (FNA) of YST metastatic from anterior mediastinum, short curvilinear nonbranching fibrils are demonstrated in the metachromatic hyaline substance. The fibril-containing hyaline substance, which presents as intracellular globules as well as extracellular matrix deposits, is a diagnostic clue for YST with parietal differentiation [Ulbright et al.: Am J Surg Pathol 1986; 10:151-164]. The fibrils are not observed in the translucent homogeneous golden yellow hyaline substance in the Papanicolaou preparation. The fibrils are speculated to be the core protein of proteoglycans. To the best of the author's knowledge, this is the first demonstration of fibrils in the hyaline substance of YST with parietal differentiation.

Adult↗
PubMed1994

The mathematical basis for the increased sensitivity in cancer detection in air-dried cytopreparations.

It is known that the volume of a sphere is 4/3 pi r3, the area of a circle is pi r2, and the nuclear volume remains constant even when a cell is flattened. The effect of air-drying that flattens a spherical nucleus with a radius of r to a discoid nucleus with an expanded radius of R and a thickness of T can be stated as follows: pi R2 = (4/3 pi r3)/T. Based on this formula, a graph was plotted to illustrate the effect of air-drying on the observed nuclear areas (ONA) of cells of various size. The ONA of ethanol-fixed Pap/H&E-stained cells or cells in tissue sections is pi r2; the ONA of air-dried Diff-Quik-stained cells is pi R (2), i.e., (4/3 pi r3)/T. The former follows a first-order straight line, and the latter follows a second-order curve. As a consequence, the subtle "nuclear size enlargement" and "broader nuclear size distribution" of low-grade cancer cells, detectable only by statistical analysis of the data obtained by an image analyzer in ethanol-fixed cytopreparations or in formaldehyde-fixed tissue sections, become augmented to such a degree on the air-dried Diff-Quik-stained preparations that they are easily detected by direct microscopic observation. In conclusion, the increased sensitivity in cancer detection in air-dried cytopreparations is due to the fact that the ONA of air-dried cells reflects nuclear volume.

Cell Nucleus↗
PubMed1994

Correlative study on findings of dynamic myelography and surgical operation in non-bony lumbar spinal canal stenosis.

The authors performed dynamic lumbar myelography with Omnipaque on 110 patients from 1990 to 1992, of them, 33 cases were diagnosed as non-bony lumbar spinal canal stenosis according to contrast medium defect seen on the lateral view of the myelogram. All such cases were operated on and their dynamic pathological findings during the operation were recorded to compare with the abnormal findings observed on the myelograms, there was a high coincidence rate of 88.7%. The authors believe that the fibrous degenerative changes make up the basis of dural sac compression and the dynamic compression in the spinal canal plays a very important role in causing the severity of the stenosis. As the dynamic pathological findings on the myelograms can not be well demonstrated on CT scanning and MR imaging, the dynamic lumbar myelography should be the method of choice for use in some cases.

Adult↗
PubMed1993

The detection of acquired immunodeficiency syndrome-associated Kaposi sarcoma cells in pleural effusion by CD34 immunostain.

BACKGROUND: Acquired immunodeficiency syndrome (AIDS)-associated Kaposi sarcoma (KS) cells have not been reported in pleural effusions. This study identifies the effusional form of AIDS-KS cells with the CD34 antibody, a newly recognized marker for vascular neoplasia. METHODS: In the pleural effusion of a patient with AIDS and biopsy proven pulmonary KS, the authors found bizarre amoeboid cells. Parallel sections from the cell blocks of the pleural effusions from the index patient and six other patients with AIDS were immunostained for cytokeratin, CD68, leukocyte common antigen (LCA), Factor VII:R, and CD34. RESULTS: The atypical cells were not observed in the pleural effusions of the other six patients with AIDS. The atypical cells were positive for CD34 (4+) and Factor VIII:R (1+) but were negative for cytokeratin, CD68, or LCA, which were expressed by mesothelial cells, macrophages, and lymphocytes, respectively. The expression for CD34 and Factor VIII:R was limited to a sharply delineated perinuclear region in the cytoplasm, corresponding to the erythrocyte-containing intracytoplasmic space of the atypical cells on the filter. CONCLUSION: In conclusion, the erythrocyte-containing intracytoplasmic space within the atypical cells most likely represents the intracytoplasmic lumina of the AIDS-KS endothelial cells and the CD-34-positive atypical cells represent the effusional form of the AIDS-KS cells.

AIDS-Related Complex↗
PubMed1992

Superficial nuclear enlargement without koilocytosis as an expression of human papillomavirus infection of the uterine cervix: an in situ hybridization study.

Nuclear enlargement of the superficial cervical epithelial cells in the absence of koilocytosis is frequently observed. The purpose of this study was to investigate whether this change represents human papillomavirus (HPV) infection. We reviewed 257 cervical biopsies with the diagnosis of "suggestive of condyloma," mild or moderate dysplasia, or both. Of the 257 consecutive biopsies, 23 fulfilled the two criteria: the superficial cells had a nuclear diameter of at least twice that of the basal nuclei, and complete absence of koilocytosis was seen. Parallel sections from each paraffin block were hybridized with biotinylated probes for HPV 6/11, 16/18, and 31/35/51 under high-stringency conditions. The cases that were negative at high-stringency conditions were then hybridized under low-stringency conditions with a mixture of the three HPV probes. Twelve of the 23 cases (52.17%) were positive for HPV, including one positive for HPV 16/18 in one area and for HPV 31/35/51 in another area, four positive for HPV 31/35/51, two positive for HPV 16/18, two positive for HPV 6/11, and three positive for HPV probe mixture at low-stringency conditions. The positive in situ hybridization was located predominantly in the enlarged nuclei in the superficial layers. In conclusion, HPV infection can be expressed as nuclear enlargement in the superficial layers of the cervical epithelium in the absence of koilocytosis.

Cell Nucleus↗
PubMed1992

Relation between exposure to respirable silica dust and silicosis in a tungsten mine in China.

To estimate the quantitative relation between exposure to respirable silica dust and risk of an attack of silicosis, 1151 workers exposed to silica dust and employed from 1958 to 1987 in a tungsten mine in China were investigated. The results showed that the ratio of respirable silica dust concentration to total silica dust concentration was 0.529. Then, the total silica dust concentration in historical surveillance and monitoring data was converted to respirable silica dust concentration. The free silica content in respirable dust determined by x ray diffraction averaged 24.7%. Multiple logistic regression was used for the dichotomous dependent variables (presence or absence of silicosis). The independent variables in the multiple logistic regression with presence of silicosis as the dependent variable were age when first exposed, tuberculosis (presence or absence), and cumulative exposure to respirable silica dust. The partial regression coefficient of individual cumulative exposure was estimated as 0.079. It implied a positive association between exposure to respirable silica dust and risk of an attack of silicosis. The exposure limit for respirable silica dust was estimated as 0.24 mg/m3 under given conditions.

Dust↗
PubMed1992

Ultrastructural immunohistochemical localization of polyclonal IgG, C3, and amyloid P component on the congo red-negative amyloid-like fibrils of fibrillary glomerulopathy.

Renal biopsies from seven patients with Congo red-negative amyloid-like fibrillary glomerulopathy (FGP) were examined by protein A gold immuno-electron microscopy. Ultrastructurally, the fibrils in all cases exhibited positive immunostaining for IgG, both Ig light chains, C3, and amyloid P component (AP), but did not show positive immunostaining for glomerular basement membrane (GBM)-associated proteins (collagen type IV and heparan-sulfate proteoglycans) or microfibril-associated proteins (fibronectin and fibrillin). In a triple-label study, AP and IgG were colocalized along the same fibril, whereas the gold probes for the detection of collagen type IV were absent. The results suggest that the fibrils are comprised of polyclonal IgG and C3 that bind AP. AP was immunolocalized sparsely but regularly along the lamina rara interna of normal GBM. AP was absent in the fibrils in a case of diabetic glomerulopathy, was scattered randomly without specificity for the electron-dense deposits in the GBM of membranous glomerulopathy, and lined up regularly along the fibrils in amyloid deposits. FGP is an entity in which the fibrils bind AP but lack the beta-pleated sheet structure necessary for Congo red staining that is typical of amyloid.

Amyloid↗
PubMed1991

Structure of the human type I DNA topoisomerase gene.

We describe the molecular organization of the human gene coding for type I DNA topoisomerase. The coding sequence is split into 21 exons distributed over at least 85 kilobase pairs (kb) of human genomic DNA. The sizes of the 20 introns vary widely between 0.2 and at least 30 kb and all contain the sequence elements known to be required for pre-mRNA splicing. Several of the intron sequences separate exons encoding parts of the enzyme that are highly conserved between human and yeast suggesting that at least some of the exons may code for individual, structurally, or functionally important domains of the enzyme. We also describe the promoter sequence of the human topoisomerase I gene and show that it is composed of distinct functional elements.

Amino Acid Sequence↗
PubMed1991

Mixed (composite) glandular-endocrine cell carcinoma of the stomach. Report of a case and review of literature.

A case of mixed (composite) glandular-endocrine cell carcinoma of the stomach is presented. Whereas the admixture of rare endocrine cells in ordinary adenocarcinoma of the stomach is a rather frequent occurrence, gastric tumors with an approximately equal proportion of glandular and endocrine cells are rare, and only 20 well-documented cases have been reported. Our case is unique in its range of histopathologic patterns, including well-differentiated and poorly differentiated adenoendocrine carcinoma as well as amphicrine differentiation. Immunohistochemical and electron microscopic findings are documented and the clinical characteristics of all reported cases tabulated. From the limited experience of these 21 cases, glandular-endocrine carcinoma of the stomach is found to have the following clinicopathologic features: It affects adults aged 32 to 74 years, (mean, 52.5 years) and has a male:female ratio of 1.3:1. It is located with almost equal frequency in the gastric body and antrum and has a poor prognosis, similar to that of advanced ordinary gastric carcinoma.

Adult↗
PubMed1990

Molecular structures of two human DNA topoisomerase I retrosequences.

We have isolated recombinant lambda-phage clones that contain sequences complementary to the 3' half of the cDNA encoding human topoisomerase I (hTOP1). These lambda clones belong to three distinct classes: class-I clones contain sequences from the active gene located on human chromosome 20. Class-II and class-III clones contain sequences corresponding to the cDNA encoding hTOP1 from nucleotide (nt) 2208 to 3434 and from nt 1639 to 3434, respectively. These sequences exhibit the characteristic features of retroposons or retrosequences. They are most likely derived from truncated mRNA transcripts of the active gene. We propose to designate the truncated hTOP1 sequence located on chromosome 1 as the pseudogene 1 (psi 1-hTOP1) and the sequence on chromosome 22 as the pseudogene 2 (psi 2-hTOP1). Pseudogene psi 1-hTOP1 has two unique properties: it is flanked by upstream sequences which display promoter activity in transient expression assays, and it contains an open reading frame which could code for the 211 C-terminal amino acids of hTOP1. Pseudogene psi 2-hTOP1 is located within an AluI repetitive element and is flanked on one side by a (CA)21 stretch.

Base Sequence↗
PubMed1990

Protein A-gold immunoelectron microscopic study of amyloid fibrils, granular deposits, and fibrillar luminal aggregates in renal amyloidosis.

Glomeruli of archival renal biopsies, stored frozen at -70 degrees C, from three patients with amyloid were examined by protein A-gold immunoelectron microscopy. In one with both fibrillar and granular deposits from a 'skin popper' drug abuser, the granular deposits were labeled with anti-IgG, while the fibrillar deposits were labeled with anti-amyloid-A (AA) protein and amyloid P component (AP), suggesting coexisting immune complex disease and AA due to different, but possibly related, pathogenesis. In studies using double-label immunostaining of primary amyloidosis-lambda light chain type (AL) and AA associated with Crohn's disease, AP occurred as widely separated single units along the amyloid fibrils and represented 1.5% and 6.5% of the total gold label in AL and AA, respectively, while the major fibril protein was labeled in single rows, similar to beads on a string. Fibrillar aggregates in the capillary lumens were labeled similarly by antisera to the major protein and AP and appeared to be contiguous with the fibrillar deposits at the glomerular basement membrane (GBM)-luminal interface, suggesting intravascular fibrillogenesis.

Amyloid↗
PubMed1989

Localization of the active type I DNA topoisomerase gene on human chromosome 20q11.2-13.1, and two pseudogenes on chromosomes 1q23-24 and 22q11.2-13.1.

Different subfragments of a cDNA coding for DNA topoisomerase I were used as probes to determine the chromosomal localization of topoisomerase I sequences in human cells. Southern blotting of restricted DNA from a panel of rodent-human somatic cell hybrids revealed the localization of the complete gene on chromosome 20 and the presence of two truncated topoisomerase I pseudogene sequences on chromosomes 1 and 22. In situ chromosome hybridization experiments confirmed these results showing the location of the complete gene on band q11.2-13.1 of chromosome 20, and the location of the pseudogene sequences on band q23-24 of chromosome 1 and q11.2-13.1 of chromosome 22.

Blotting, Southern↗