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Biomedical subjects

D McCormick

Publications and source records attributed to D McCormick.

At least 91 records · Page 5Linked to original sources
PubMed1987

An in-vitro study of irradiated vitreo-retinal membranes.

Standard perforating injuries were created in the right eye of 30 rabbits. Twenty of these had the site of injury irradiated using the radioactive ophthalmic 60Cobalt applicator. Vitreo-retinal membranes obtained from non-irradiated and irradiated eyes were propagated in vitro. The morphology and viability of the cells that grew as a monolayer was studied using phase, light and electron microscopy. The proportions of the different cell types that constituted the monolayer was determined using immunofluorescent staining techniques. Non-irradiated membranes elaborated an abundant outgrowth of healthy cells that were predominantly fibroblasts. Irradiated membranes developed a sparse outgrowth of cells with vacuolated cytoplasm and pyknotic nuclei indicating cell destruction. The majority of the surviving cells were glial, with fibroblasts and retinal pigment epithelial cells forming the remainder.

Animals↗
PubMed1987

Structure of the glycosaminoglycan domain in the type IX collagen-proteoglycan.

Type IX collagen represents 5-20% of the total collagen in hyaline cartilage. The molecules of this collagen are composed of three genetically distinct polypeptide subunits. One of these subunits, alpha 2(IX), contains covalently bound glycosaminoglycan (chondroitin sulfate or dermatan sulfate). We report here on the structure of the glycosaminoglycan attachment site of type IX collagen-proteoglycan. We show, by a combination of cDNA and peptide sequencing, that the attachment region contains the sequence Gly-Ser-Ala-Asp, located within the noncollagenous domain NC3 of the alpha 2(IX) chain. By comparing the exons encoding the NC3 domain in the alpha 2(IX) and alpha 1(IX) genes, we find that the exon coding for the glycosaminoglycan attachment site in the alpha 2(IX) gene is 48 base pairs long, whereas the homologous alpha 1(IX) exon is 33 base pairs. The NC3 domain is, therefore, five amino acid residues longer in alpha 2(IX) than in alpha 1(IX). The extra sequence in alpha 2(IX), Val-Glu-Gly-Ser-Ala, provides a simple explanation for the kink observed at the NC3 domain of type IX molecules when examined by electron microscopy. The inserted block of amino acid residues also provides the NC3 domain of alpha 2(IX) chains with a serine residue, not present in alpha 1(IX) that serves as attachment site for a glycosaminoglycan side chain. Our data show that the amino acid sequence that surrounds the glycosylated serine residue in type IX collagen-proteoglycan differs from glycosylated sequences in noncollagenous core proteins. The data also provide strong evidence that glycosylation of type IX collagen is not a chance glycosylation of a serine residue in a noncollagenous domain, but is a specific post-translational modification of this unusual collagen molecule.

Amino Acid Sequence↗
PubMed1986

Right heart obstruction due to intracavitary prolymphocytic leukemia.

A 52-year-old woman with prolymphocytic leukemia in whom right heart failure developed from leukemic infiltration of the heart with right ventricular outflow tract obstruction is described. Two-dimensional echocardiography helped guide successful treatment of this complication with radiation and chemotherapy.

Echocardiography↗
PubMed1986

Studies on the secretion, metabolism and action of atrial natriuretic peptide in man.

Radio-immunoassay of atrial natriuretic peptide (ANP) and infusions of alpha-human ANP (alpha-hANP) have been used to study the secretion, metabolism, regulation and actions of ANP in man. Plasma immunoreactive ANP (irANP) was twice as high in arterial blood as in simultaneously sampled venous plasma from the femoral, hepatic and renal vein, but no arteriovenous difference was found across the lung. Analysis of plasma extracts by high performance liquid chromatography confirmed that alpha-hANP-like material was a major component in coronary sinus and peripheral arterial and venous plasma. In normal subjects, venous plasma irANP was increased by both acute and chronic sodium loads, and by exercise. The cardiac secretion of irANP, and peripheral venous levels, were markedly increased by atrial pacing in four patients investigated for arrhythmia. Plasma irANP concentrations were elevated in many patients with circulatory disorders, including chronic renal failure, congestive heart failure and during spontaneous tachyarrhythmias. Constant 60-min intravenous infusions of alpha-hANP increased urinary sodium excretion in normal subjects, under conditions of both high- and low-sodium intake, and selectively reduced plasma aldosterone concentrations. These effects were observed at the venous levels of plasma irANP found in some patients with circulatory disease. Taken together, the present studies suggest that ANP has important endocrine functions in human health and disease.

Aldosterone↗
PubMed1984

Production of glial fibrillary acidic protein (GFAP) by neoplastic cells: adaptation to the microenvironment.

In 80 specimens of human glioma the production of glial fibrillary acidic protein (GFAP) by tumour cells invading meninges or connective tissue was studied immuno-cytochemically by the PAP technique. In 38 of 55 cases of astrocytoma, glioblastoma, gliosarcoma, and oligoastrocytoma, GFAP immunoreactivity was greater in the invading cells as compared with the main part of the neoplasm. Fifty-eight percent of the astroglial tumours invading the leptomeninges, all astroglial tumours invading connective tissue and all gliosarcomas showed enhanced GFAP immuno-reactivity of tumour cells getting in contact with collagenous tissue, whereas meningeal infiltrates of 25 non-astroglial tumours (oligodendroglioma, ependymoma, medulloblastoma) remained GFAP-negative like the main part of the respective tumours. In the majority of astroglial tumours an increase of GFAP immunoreactivity was found also in perivascular cells of the main part of the tumour. It is concluded that glioma cells are capable of adapting their cytoskeleton to their micro-environment. Contact with dense collagenous tissue appears as an important factor able to induce an increased production of GFAP by adjacent glial cells.

Astrocytoma↗
PubMed1983

The establishment and characterization of a cell line and mouse xenografts from a human malignant melanoma.

A permanent cell line has been established from a human intracranial secondary melanoma. During 3 years of continuous growth in vitro the cells have maintained their characteristic phenotypic properties including melanin production. The cultured cells are highly tumorigenic in the athymic mouse and the tumours produced are histologically identical to the human tumour of origin.

Animals↗
PubMed1981

An investigation in vitro of the exocytosis of lysosomal enzymes from C6 glioma cells.

The rates of exocytosis on the lysosomal hydrolase n-acetyl-beta D-glucosaminidase and beta-glucuronidase were measured in monolayer cultures of the C-6 glioma cell line. A comparison of the kinetics of release of the enzymes and the effects of cytochalasin B suggest that either intralysosomal localisation or the mechanism of release may be different for each enzyme. Evidence was obtained that exocytosis is accompanied by receptor-mediated endocytosis of hydrolases and the importance of the microtubular system in the maintenance of the exocytosis equilibrium was indicated by the effect of colchicine on the rate of extracellular accumulation of the enzymes.

Acetylglucosaminidase↗
PubMed1981

Heel deformity in hereditary spastic paraplegia.

The association of pes cavus deformity and neurological disorder is well known. Varus deformity of the heel is often associated with, and may even precede the development of pes cavus. Clinical and radiographic examinations of the feet of members of three kindreds of hereditary spastic paraplegia, a rare neurologic disorder, suggested that the autosomal dominant form manifests a significantly higher incidence and degree of heel varus deformity than the autosomal recessive form of the disease. Therefore, heel varus deformity may be a sign suggestive of autosomal dominant inheritance of hereditary spastic paraplegia.

Adult↗
PubMed1977

LDH isoenzyme pattern in a meningioma with pulmonary metastases.

The case is presented of an intraspinal meningioma in a 14-yr-old female. After surgical exploration pulmonary metastases became apparent. At necropsy the tumour had increased proportions of the cathodal isoenzymes LDH-4 and 5. This pattern has previously been observed in malignant meningiomas and may be used at the time of biopsy to assess malignancy.

Adolescent↗