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Biomedical subjects

A S Ma

Publications and source records attributed to A S Ma.

14 recordsLinked to original sources
PubMed1999

Multiple cutaneous metaplastic synovial cysts.

The cutaneous metaplastic synovial cyst is a recently described lesion that characteristically presents as a solitary, tender subcutaneous nodule. On histopathologic examination, the lesion is characterized by a cystic structure with villous-like projections and a lining resembling hyperlastic synovium. The cause of cutaneous metaplastic synovial cysts is unclear, but trauma is presumed to be a precipitating factor, as most reported cases have a history of antecedent cutaneous injury. Here we present a case of multiple, bilateral cutaneous metaplastic synovial cysts in a 72-year-old white man with rheumatoid arthritis. This is the first reported case of a patient with multiple lesions. The characteristic clinical and pathologic features of this lesion, along with proposed cause, are reviewed herein.

Aged↗
PubMed1997

Clinical experience of trabeculotomy for the surgical treatment of aniridic glaucoma.

OBJECTIVE: The purpose of this study is to determine the efficacy of initial trabeculotomy in the patient with aniridic glaucoma. DESIGN: Clinical charts were reviewed. PARTICIPANTS: Twenty-nine eyes of 16 patients with aniridia were studied. INTERVENTION: Glaucoma surgery was performed. As an initial procedure, trabeculotomy was performed in 12 eyes, other surgery was performed in 17 eyes (trabeculectomy, 5; goniotomy, 5; other, 7). MAIN OUTCOME MEASURES: Success was defined as an intraocular pressure (IOP) of 21 mmHg or lower, and no further surgery was performed. RESULTS: Ten (83%) of 12 eyes obtained IOP control after first (6 eyes) or second (4 eyes) trabeculotomy with a mean follow-up period of 9.5 years. Five eyes maintained visual acuity of 20/40 to 20/200. No serious complications were found after trabeculotomy. Three (18%) of 17 eyes were controlled with the first glaucoma surgery other than trabeculotomy (goniotomy, trabeculectomy, trabeculectomy combined with trabeculotomy, and Molteno implant). Good IOP control was obtained in 8 (47%) of 17 eyes after several surgeries with a mean follow-up period of 10.4 years. Four of 17 eyes became phthisical. CONCLUSION: This study suggests that trabeculotomy is the preferred initial operation for uncontrolled glaucoma with aniridia.

Adolescent↗
PubMed1997

Endoscopic diode laser cyclophotocoagulation with a limbal approach.

BACKGROUND AND OBJECTIVE: Endoscopic diode laser cyclophotocoagulation with a limbal approach was reviewed retrospectively. The delivery system and procedure used as well as the role of this procedure in the management of glaucoma are discussed. PATIENTS AND METHODS: An 810-nm pulsed continuous-wave diode laser capable of 1.2-W output was used. The maximum treatment area is 7 to 8 clock hours with a single limbal incision. Generally, 800 mW were used for less than 1 second, for a total of 0.8 J per treatment. RESULTS: Eight eyes of 6 patients were treated. The mean follow-up time for each procedure was 3.2 months (range 1 to 8 months) and for each eye was 5.1 months (range 2 to 8 months). Pre- and postoperative intraocular pressures were determined. Postoperative inflammation was the most common complication. CONCLUSION: One reason for the failure of transscleral cyclophotocoagulation, particularly in congenital glaucoma, may be displacement of the ciliary processes. This displacement does not permit the indirect treatment to reach the appropriate area. Because endoscopic laser cyclophotocoagulation allows direct visualization, treatment can be accurately applied to individual ciliary processes.

Adult↗
PubMed1996

Annexins I and II show differences in subcellular localization and differentiation-related changes in human epidermal keratinocytes.

The annexins are a family of calcium-dependent phospholipid-binding proteins whose in vitro properties have led to a number of hypotheses suggesting their cellular functions, including membrane fusion in exocytosis and endocytosis. To investigate the topography and possible functions of these proteins we compared the subcellular localization of annexins I, II, IV and VI in skin sections and in cultured epidermal keratinocytes by immunostaining. We found that annexin I staining was in a granular pattern in the monolayer epithelial cells but in an envelope pattern in the stratified keratinocytes. This finding corroborates previous reports that annexin I crosslinks to form cornified envelopes in the mid-epidermis and explains the absence of staining above that level. It is unlikely that this protein is related to exocytosis in the granular layer of the epidermis. In comparison, annexin II staining was also granular and was detected in all nucleated epidermal cells as bands at the cell periphery. However, only annexin II was detected extracellularly among the top layer of cultured cells. The intracellular linear envelope pattern of annexin I and the intercellular pattern of annexin II suggest their interactions with the membrane cytoskeleton in other biological functions. Taken together, both annexins undergo different differentiation-related changes. While methanol fixation enhanced staining of annexin I, it diminished staining of annexin II. Their opposite responses to methanol fixative suggests a different molecular organization of the two annexins with phospholipid in the cell membrane. Annexins IV and VI were predominantly confined to dermal cells including ductal and myoepithelial cells and were not detected in cultured keratinocytes using either cold methanol fixative or prefixation labeling.

Annexin A1↗
PubMed1996

A high prevalence of occludable angles in a Vietnamese population.

PURPOSE: To assess the prevalence of occludable angles in a Vietnamese population. METHODS: The authors retrospectively reviewed the angle status in 482 Vietnamese patients who presented to a general ophthalmology practice. All angles were graded by a glaucoma specialist according to the Shaffer method. Patients were excluded if they had known glaucoma or narrow angles, or a history of trauma or intraocular surgery. RESULTS: A total of 29.5% of all patients surveyed and 47.8% of those 55 years of age or older had grade 0 to 2 angles. In the Framingham study, 3.8% of white patients 55 years of age or older had grade 0 to 2 angles. Of the patients in our study population, 8.5% had grade 0 to 1 angles and were considered at high risk for occlusion. CONCLUSIONS: Vietnamese patients have a much higher prevalence of narrow angles and a greater risk of angle-closure glaucoma than white patients.

Adolescent↗
PubMed1996

Update on the subconjunctival THC:YAG (holmium) laser sclerostomy Ab externo clinical trial: a 4-year report.

BACKGROUND AND OBJECTIVE: This is a follow-up report on 103 THC:YAG (holmium) sclerostomies ab externo performed on 87 eyes of 81 patients. PATIENTS AND METHODS: The patients received pulse energies of 0.06 to 0.13 J (mean total energy 4.4 +/- 3.3 J, range 0.6 to 17.1 J). RESULTS: The estimated success rates with or without medication, and allowing a second procedure, were 44% at 2 years and 36% at 4 years. The mean preoperative intraocular pressure (IOP) was 29.7 +/- 11.4 mm Hg, and the mean postoperative IOP in the successful patients was 13.6 +/- 4.6 mm Hg (P < .01). Hypotony and iris incarceration were the most frequent early complications. CONCLUSIONS: Although holmium laser sclerostomy is a relatively straightforward procedure and offers some advantages over standard trabeculectomy in select cases, it currently has a number of drawbacks that limit its use.

Adolescent↗
PubMed1994

In vitro modulation of filament bundling in F-actin and keratins by annexin II and calcium.

In our preliminary subcellular localization experiment we demonstrated that annexin II co-localized with submembranous actin in subpopulations of both cultured fibroblasts and keratinocytes. To investigate the physical interaction between annexin II and actin at the cell periphery, in vitro reconstitution experiments were carried out with keratins used as a control. Annexin II, isolated by immunoaffinity column chromatography, was found to exist as globular structures measuring 10 to 25 nm in diameter by rotary shadowing, similar to a previous report. We believe that these structures represent its polymeric forms. By negative staining, monomeric annexin II was detectable as tapered rods, measuring 6 nm in length and 1 to 2 nm in diameter. When annexin II was mixed with actin in 3 mM piperazine-N, N-bis-2-ethanesulfonic acid (PIPES) buffer with 10 mM NaCl2, 2 mM MgCl2 and 0.1 mM CaCl2, thick twisting actin bundles formed, confirming previous reports. This bundling was much reduced when calcium was removed. In the presence of 5 mM ethylenediamine tetra-acetic acid (EDTA) in 5 mM tris, pH 7.2, keratins were found to form a network of filaments, which began to disassemble when the chelator was removed and became fragmented when 0.1 mM CaCl2 was added. Keratins under the same conditions did not fragment when annexin II was present. These results suggest that annexin II, in conjunction with Ca2+, may be involved in a flexible system accommodating changes in the membrane cytoskeletal framework at the cell periphery in keratinocytes.

3T3 Cells↗
PubMed1994

Immunocytochemical detection of extracellular annexin II in cultured human skin keratinocytes and isolation of annexin II isoforms enriched in the extracellular pool.

Monoclonal antibodies were raised against trypsinized human skin epidermal cells and selected for their staining of the epidermal cells in a cell periphery pattern. One antibody, CP-1, immunoprecipitated a 36 kDa protein that was identified as annexin II heavy chain by microsequencing of a CNBr-generated peptide fragment from the antigen and by cross-identification with another anti-annexin II antibody. In addition to staining a broad cell periphery band in keratinocytes, CP-1 also detected annexin II outside and in between the top layer cells before cell permeabilization. Double-labeling of annexin II and F-actin revealed a distinct topographical relationship between the two, with intercellular annexin II flanked by the submembranously located actin of the juxta-positioned cells. Annexin II was isolated from cultured keratinocytes via immunoaffinity column chromatography in one step, using the same monoclonal antibody CP-1 and was found to be resolved into multiple isoforms when analyzed by two-dimensional gel electrophoresis. The predominant components of annexin II were basic, with pI of 6.5-8.5, and some of them formed disulfide-linked monomeric multimers under non-reducing conditions. Acidic annexin II isoforms with pI 5.4-5.8 were barely detectable among the total annexin II isolated but were selectively enriched in an extracellular pool created by 0.05% ethylenediaminetetraacetic acid (EDTA) dispersion of the cultured cells into single cell suspensions. Furthermore, they can be separated from the rest of annexin II by using a different elution condition. A 46 kDa protein, the identity of which is unclear, co-eluted with the acidic isoforms in the EDTA washes. These acidic isoforms, which co-eluted with the 46 kDa protein, are suspected of corresponding to the extracellular annexin II detected immunocytochemically.

Amino Acid Sequence↗
PubMed1990

Aberrant proliferation of lumen-forming cells in stratified epithelium of porokeratosis skin.

The present investigation was based on the postulate, first proposed by Reed and Leone in 1970, that porokeratosis lesions represent clonal growth of epidermal cells. Comparative studies using immunocytochemical staining, epidermal cell culture, and non-equilibrium pH gradient (NEpHG) gel electrophoresis analysis of the keratins extracted were carried out on five patients with various types of porokeratosis. Positive type IV collagen staining on the stratum corneum was found in lesional skin specimens of all patients, but not in normal controls. A search for connections between type IV collagen in the basement membrane of epidermis and the skin surface disclosed infrequent intra-epidermal streaking of type IV collagen and one positively stained trans-epidermal acrosyringium. Positive intra-epidermal laminin staining in porokeratosis lesions confirmed the trans-epidermal passage of basement-membrane materials. Epidermal cells cultured from lesional skin showed low plating efficiency, and all colonies exhibited intracytoplasmic vacuole formation and excessive top cell shedding. NEpHG gel electrophoresis of keratins extracted showed that lesional profiles not only contained keratins normally present in glabrous skin, but also possibly K9 and some additional proteins. K9 had been immunolocalized to periductal cells in previous studies. Our findings, taken together, strongly suggest that porokeratosis epidermis consists of epithelial cells with lumen-forming ability.

Blotting, Western↗
PubMed1988

Alignment of desmosomes in stratifying human epidermis.

Cultured human epithelial cells stained with antibody to desmosomal proteins by indirect immunofluorescence showed linear arrays of desmosomes en face between stratified cells. To confirm that an extensive linear pattern existed on the cell surface, subconfluent cultures were viewed using scanning electron microscopy. Aligned arrays of blunt protrusions lying parallel to each other and extending in the direction of the long axis of the cell were observed on the surface of groups of superficial cells in intact cultures. That this pattern was indeed related to desmosomal distribution was verified by transmission microscopy of thin sections cut in a plane between the upper and lower surfaces of flattened stratified cells to view desmosomes directly. A similar arrangement of desmosomes was seen in intact tissue, using epidermal sheets separated from newborn foreskin. The same pattern found in flattened cells was sometimes apparent in more rounded basal cells where the cytoplasm was beginning to extend. Since desmosomal plaques are associated with keratin filaments, the alignment of desmosomes must occur in association with cytoskeletal changes as cells become flattened toward the distal epithelial surface. The primary initiation of desmosomal alignment remains to be investigated. However, the present findings demonstrate an increasingly regular membrane-cytoskeletal spatial interaction as stratified epithelial cells of skin mature.

Cells, Cultured↗
PubMed1988

Immunofluorescence localization of peripheral proteins in cultured human keratinocytes.

To gain preliminary data on the location of a 195 kD cell peripheral protein of epidermal keratinocytes recognized by monoclonal antibody AE11, immunofluorescence staining was carried out on cultured human epidermal cells. B11 antidesmosomal polyclonal antibody and AE3 antikeratin monoclonal antibody staining were used as comparative reference controls. Desmosomal antigens span the cell membrane and keratins constitute a family of cytoplasmic proteins. The cultured cells were systematically used either unfixed, fixed with 4% paraformaldehyde, or fixed with methanol at 4 degrees C. The former two preparations were designed to expose only the surface antigens, whereas the latter method permeated the membrane to allow cytoplasmic staining. Differences in staining patterns were observed in the basal layer as compared with the upper layers with all three antibodies. B11 antidesmosomal antibody staining was consistent in pattern after either paraformaldehyde or methanol fixation. In addition to the punctate staining along adjacent cell surfaces as shown in the basal layer, the surface planes of the upper cells exhibited parallel arrays of linear streaks, demonstrating the distribution of desmosomal proteins. Antikeratin staining by AE3 showed the typical filamentous staining in basal cells. However, a homogeneous patchy staining of suprabasal cells was observed. The presence of punctate surface staining using antikeratin antibody on paraformaldehyde fixed cells suggests leakage of keratin to the cell surface. AE11 showed stronger staining in the top cells on methanol treated cultures and a punctate surface staining of the cells fixed with paraformaldehyde. These observations provide useful preliminary information in localizing peripheral proteins in epidermal keratinocytes.

Cells, Cultured↗
PubMed1986

Differentiation-dependent changes in the solubility of a 195-kD protein in human epidermal keratinocytes.

We have prepared a monoclonal antibody, AE11, that recognizes specifically a 195-kD protein (pI 5.4) of human keratinocytes. This antigen constitutes approximately 0.01-0.1% of total protein in keratinocytes of skin, esophagus, and cornea, and is readily detectable in these cells by immunofluorescent staining and immunoblotting. However, it is barely detectable in MCF mammary carcinoma cells and HeLa cells, and is undetectable in nonepithelial cell types. Results from serial extraction experiments have shown that this protein exists in two distinct pools: a Tris-soluble, and a Tris-insoluble but urea- or SDS-soluble one. The distribution of the 195-kD protein between these two pools appears to be differentiation-related, since relatively undifferentiated cells selected by a low-calcium medium contain primarily the soluble form, while highly differentiated cells contain mainly the insoluble form. Data from immunofluorescent staining and trypsin-sensitivity experiments suggest that the soluble form is cytoplasmic, whereas the insoluble form is submembranously located at the cell periphery of upper, differentiated cells. The insoluble, cell peripheral form of the 195-kD antigen increases progressively during epidermal differentiation; its insolubility appears to be related to the formation of disulfide-bond(s). These results indicate that the 195-kD protein, which has recently been suggested to be involved in cornified envelope formation (Simon, M., and H. Green, 1985, Cell, 36:827-834), undergoes significant changes in its solubility characteristics and intracellular location during keratinocyte maturation.

Antibodies, Monoclonal↗
PubMed1984

Cutaneous immunofluorescence studies in adult rheumatoid arthritis in sun-exposed and non-sun-exposed areas.

The incidence and significance of positive cutaneous immunofluorescence findings were assessed in biopsy specimens of both sun-exposed and non-sun-exposed skin of 34 adult patients with rheumatoid arthritis (RA) who were not receiving systemic corticosteroids. The incidence of lupus erythematosus (LE)-band was low (8.6%) in both groups. Twenty-eight percent of the patients had perivascular IgM and/or C3 deposits, and 74% had cytoid bodies in the papillary dermis. These studies indicate that the incidence of LE band is low in RA and that the detection of such a band in normal skin warrants close follow-up of RA patients for possible development of LE.

Adult↗