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Biomedical subjects

A Hidayat

Publications and source records attributed to A Hidayat.

10 recordsLinked to original sources
PubMed1997

Amperometric detection of organic thiols at a tungsten wire electrode following their separation by liquid chromatography.

The amperometric detection of thiols following their separation by reversed-phase chromatography and reaction into a post-column mercury carrier stream is shown to be a sensitive method when using a tungsten wire sensor as the working electrode in a three-electrode flow cell. Five organic thiols (cysteine, homocysteine, reduced glutathione, D,L-penicillamine and 2-mercaptopropionic acid) and thiourea could be separated within approx. 18 min. The analytical performance is comparable, and stability superior, to chemically modified electrodes previously reported.

Chromatography, Liquid↗
PubMed1993

The histopathology and the mechanism of entropion in patients with trachoma.

BACKGROUND: Eyelids of patients with trachoma may be thickened. This thickening could be attributed to trachomatous changes in the conjunctiva and tarsus. METHODS: Biopsies of tarsal plates and palpebral conjunctivae were obtained from 17 upper eyelids of 11 patients with inactive trachoma who underwent posterior tarsotomy procedures for entropion repair. RESULTS: Light microscopy studies showed a thick and compact subepithelial fibrous membrane adherent to the tarsal plate. This membrane caused apparent thickening of the tarsus when measured intraoperatively (range, 1.25-2.00 mm). Other histopathologic findings include atrophy of the meibomian glands with thickening of the acinar basement membrane, loss of goblet cells, retention cysts, and hyaline degeneration of the tarsal plate with focal replacement by adipose tissue. CONCLUSION: The contraction of the subepithelial fibrous membrane formed by vertically oriented parallel collagen fibers is one of the main factors contributing to the entropion formation.

Adult↗
PubMed1990

Ciliary body melanoma with optic nerve invasion.

A case of melanoma of the ciliary body is presented. Initially the patient was diagnosed and treated for uveitis, but following CT scanning and ultrasound a tumour was detected and the eye enucleated. Histopathologically it was found that the tumour had invaded the optic nerve head, apparently via Cloquet's canal.

Adult↗
PubMed1988

Pleomorphic adenocarcinoma of ciliary epithelium simulating an epibulbar tumor.

A 72-year-old woman had epibulbar nodules and a blind eye following trauma in childhood. Histologic examination disclosed a pleomorphic adenocarcinoma of ciliary epithelium with invasion of the epibulbar region, retina, retinal pigment epithelium, and optic nerve. The diagnosis was confirmed by histochemical stains and electron microscopy. The pigmented and nonpigmented neoplastic cells of the ciliary epithelium had a patchy basement membrane around the cell membrane and produced hyaluronic acid in the stroma.

Adenocarcinoma↗
PubMed1988

Retinoblastoma: the Saudi Arabian experience.

During the period March 1983-May 1987, 74 cases of retinoblastoma were evaluated at the King Khaled Eye Specialist Hospital in Riyadh, Saudi Arabia. 60% of the cases were unilateral with a female preponderance of 59.4% noted for this series. Additionally, the mean age at diagnosis was 22 months, and delay of retinoblastoma diagnosis since the first symptoms were observed ranged from two days to 36 months. Fifty-seven eyes were enucleated, and in 21 of these patients, this was the sole form of therapy. The remainder of patients were treated with radiotherapy alone or combined with chemotherapy, cryotherapy/photocoagulation. Overall, two-year survival statistics of this group of Saudi patients is 80% which compares favorably to other reports in the West. Emphasis is placed on management of the retinoblastoma patients by a multi-disciplinary group, and public educational efforts are imperative.

Child↗
PubMed1984

Conjunctival myxoma: a case report.

A rare case of conjunctival myxoma in an 18-year-old female is reported. Clinically it presented as a painless mass located in the nasal bulbar conjunctiva. It was composed of spindle and stellate shaped cells in a loose mucoid stroma. Some of the cells had intracytoplasmic vacuoles consistent with dilated rough endoplasmic reticulum and/or intranuclear vacuoles of nuclear membrane invaginations. Mast cells were also seen in the stroma. No recurrence has been reported eight months postoperatively.

Adolescent↗
PubMed1984

Conjunctival synthetic fiber granuloma. A lesion that resembles conjunctivitis nodosa.

Histopathologic examination of forniceal conjunctival lesions excised from five young patients revealed granulomatous inflammation surrounding filamentous foreign material. Polarization microscopy, special histochemical stains, scanning electron microscopy and energy dispersive x-ray elemental analysis identified the inciting material as predominantly synthetic fabric fiber. Three of these cases initially were diagnosed as conjunctivitis nodosa, an inflammatory reaction to caterpillar setae. Many synthetic fibers contained numerous granules of titanium, barium, or zinc delustering agent, which served to differentiate them from natural fibers or caterpillar hairs. Synthetic fabric fiber is a previously unrecognized cause of conjunctival inflammatory mass lesions.

Adolescent↗
PubMed1983

Retinocytoma. A benign variant of retinoblastoma.

Six examples of a distinctive benign retinal tumor, occurring in five children and treated only by enucleation, were studied by light and electron microscopy and tested for S-100 protein, a glial-cell tissue marker. The small placoid, noninvasive lesions were composed entirely of benign-appearing cells with numerous fleurettes. These tumors showed no necrosis or mitotic activity. Ultrastructurally, they were composed predominantly of neuronal cells exhibiting photoreceptor differentiation. Some tumor cells had cytologic features of Müller's fibers and other glial cells that in one lesion stained positively for S-100 protein. In two patients there was a family history of retinoblastoma. All children were alive and well at follow-up examinations conducted three to 14 years after enucleation. To expand our concept of retinoblastoma to include this benign variant, we propose the term "retinocytoma." Although clinically and morphologically distinct from retinoblastoma, retinocytoma should carry the same genetic implication as its malignant counterpart.

Child, Preschool↗
PubMed1981

Diffuse iris nevus manifested by unilateral open angle glaucoma.

Uncontrolled unilateral glaucoma developed in the right eye of a 24-year-old woman. It was caused by the diffuse growth of a nonpigmented nevus of the iris into the anterior chamber angle. Histologically, the nonpigmented nevus cells in the angle were distinguishable from a proliferation of corneal endothelium. Clinically, there was no heterochromia, and a tumor was not suspected as the cause of the glaucoma.

Adult↗