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Biomedical subjects

D J Demetrick

Publications and source records attributed to D J Demetrick.

At least 37 records · Page 2Linked to original sources
PubMed1994

Mutations and altered expression of p16INK4 in human cancer.

Cell cycle arrest at the G1 checkpoint allows completion of critical macromolecular events prior to S phase. Regulators of the G1 checkpoint include an inhibitor of cyclin-dependent kinase, p16INK4; two tumor-suppressor proteins, p53 and RB (the product of the retinoblastoma-susceptibility gene); and cyclin D1. Neither p16INK4 nor the RB protein was detected in 28 of 29 tumor cell lines from human lung, esophagus, liver, colon, and pancreas. The presence of p16INK4 protein is inversely correlated with detectable RB or cyclin D1 proteins and is not correlated with p53 mutations. Homozygous deletions of p16INK4 were detected in several cell lines, but intragenic mutations of this gene were unusual in either cell lines or primary tumors. Transfection of the p16INK4 cDNA expression vector into carcinoma cells inhibits their colony-forming efficiency and the p16INK4 expressing cells are selected against with continued passage in vitro. These results are consistent with the hypothesis that p16INK4 is a tumor-suppressor protein and that genetic and epigenetic abnormalities in genes controlling the G1 checkpoint can lead to both escape from senescence and cancer formation.

Base Sequence↗
PubMed1994

Chromosomal mapping of human CDK2, CDK4, and CDK5 cell cycle kinase genes.

Cyclin dependent kinases (CDK's) are kinases that interact with cyclins and regulate cell division. Genomic clones encoding human CDK2, CDK4, and CDK5 were obtained and mapped to their respective chromosomal loci using fluorescence in situ hybridization on human lymphocyte metaphase spreads. Interestingly, CDK2 and CDK4 were located at the same position, 12q13, and CDK5 was mapped to 7q36. 12q13 has been shown to be associated with chromosome alterations such as amplifications and translocations in solid tumors. 7q36 does not appear to be a major site of chromosome alterations in tumors. As CDK2 and CDK4 appear to be important in regulating the human cell cycle, it is possible that the alterations of the 12q13 locus in tumors may involve changes in the regulation of CDK2 and CDK4 genes.

CDC2-CDC28 Kinases↗
PubMed1994

Isolated cerebellar lymphomatoid granulomatosis progressing to malignant lymphoma. Case report.

A 60-year-old man presented with progressive and unique neurological symptoms. Investigations identified an isolated cerebellar lesion. This lesion fulfilled the histological criteria for lymphomatoid granulomatosis, and in situ hybridization and deoxyribonucleic acid (DNA) dot blot techniques revealed significant amounts of Epstein-Barr virus DNA within the tumor cells. The patient underwent cranial radiation therapy, and 16 months after the initial presentation the lesion evolved into a malignant lymphoma. He subsequently died secondary to subdural empyema, bacterial meningitis, and bronchopneumonia. The unique clinical and etiological aspects of this case are addressed.

Cerebellar Neoplasms↗
PubMed1993

Chromosomal assignment of the human thrombin receptor gene: localization to region q13 of chromosome 5.

A functional thrombin receptor (TR) structurally related to other members of the seven-transmembrane receptor family has been isolated from diverse cellular types intimately involved in the regulation of the thrombotic response. This receptor recapitulates many of the previously identified sequelae of thrombin-mediated cell activation phenomenon, and requires proteolytic cleavage for downstream effector-response coupling events. Using two complementary approaches, we have now completed the chromosomal assignment of the human thrombin receptor gene. Discordancy analysis of polymerase chain reaction products from a human-rodent hybrid cell mapping panel assigned the sequence to human chromosome 5 with no observed discordancies. Cytogenetic localization using fluorescence in situ hybridization on human metaphase chromosomes specifically localized the human TR gene to region q13 of chromosome 5, confirming its presence as a single-locus gene in the human genome. The chromosomal localization of the human TR gene is at or contiguous with the proximal breakpoint site identified in the majority of patients with the 5q- syndrome (dysmegakaryocytopoiesis and refractory anemia).

Chromosome Mapping↗
PubMed1993

A study of surface property changes in rat mesothelial cells induced by asbestos using aqueous two-phase polymer solutions.

Intraperitoneal (i.p.) injection of crocidolite asbestos was used to induce mesotheliomas in rats. The morphological changes of the mesothelial cells were studied by light and electron microscopy and by cytologic examination of peritoneal washings. After injection, the asbestos fibres stimulated an acute inflammatory response and were rapidly phagocytosed by the mesothelial cells and incorporated into the submesothelial tissues. At 7 days, the normal microvillous surface of the mesothelium was replaced with a syncytium of proliferating mesothelial cells showing extensive loss of microvilli. Nine months or so later, multifocal mesothelial tumours arose within the peritoneal cavity. The surface thermodynamic properties of normal, asbestos-stimulated mesothelial cells and of mesothelial tumour cells in culture were studied using an aqueous two-phase system containing 4% Dextran T-2000 and 4% poly (ethylene glycol) (PEG) w/w. After asbestos stimulation, there was a significant (P < 0.01) increase in contact angle between the dextran-rich phase and the mesothelial cell surface. These changes were even greater for the mesothelial tumours. The results indicate that the work of adhesion for asbestos-stimulated mesothelial cells and mesothelial tumours is lower than in normal tissue. These findings may be relevant to the process of tumour spread in the serosal cavities and to the development of distant metastases.

Animals↗
PubMed1993

Chromosome mapping of human CDC25A and CDC25B phosphatases.

The human CDC25 tyrosine phosphatases trigger activation of CDC2 by removing inhibitory phosphates; thus the genes encoding these phosphatases may be suspected as potential oncogenes due to their role in promoting cell division. To date, three human CDC25 genes have been identified: CDC25A, B, and C. This communication describes the mapping of CDC25A to chromosome 3p21 and CDC25B to chromosome 20p13 by fluorescence in situ hybridization with confirmation by the polymerase chain reaction of hamster-human somatic cell hybrid DNA. 3p21 is near an area frequently involved in karyotypic abnormalities in renal carcinomas, small cell carcinomas of the lung, and benign tumors of the salivary gland. 20p13 does not seem to be a common area for karyotypic alteration in tumors. Mapping of these genes to their chromosomal loci may help identify tumors with abnormal regulation of CDC25 genes due to genomic alterations.

Animals↗
PubMed1992

Epstein-Barr virus-associated primary B-cell lymphoproliferative disorder of the cerebellum in an immune competent man.

BACKGROUND: The role of the Epstein-Barr virus (EBV) in lymphoproliferative lesions has been widely accepted. Most of these lesions occur in patients who have deficiencies in their immune status. Lymphomatoid granulomatosis (LG) is a lymphoproliferative disorder originally characterized as an angiocentric, necrotizing, pleomorphic infiltrate of mononuclear cells. The etiology of LG is unknown. It was originally hypothesized that LG may represent an unusual lymphoid response to an infective organism, possibly EBV. METHODS: Tissues from a previously healthy 60-year-old, healthy white man with primary cerebellar lymphomatoid granulomatosis were examined for the presence of EBV by nucleic acid hybridization. RESULTS: The original LG lesion was a polyclonal B-cell proliferation that contained detectable amounts of EBV. Peripheral blood leukocytes were negative for EBV by the same assay. After an 18-month remission, a tumor reappeared near the site of the primary lesion, which had the histologic appearance of a lymphoma. The cells showed restricted clonality and contained a similar amount of EBV-related DNA as the original lesion. Peripheral blood leukocytes at the time of recurrence were negative for EBV. The patient died approximately 2 months after the recurrent tumor was detected. CONCLUSIONS: This case demonstrated the development of a primary cerebellar B-cell lymphoproliferative disorder, histologically identical to lymphomatoid granulomatosis, that transformed into a lymphoma. The original tumor and the subsequent lymphoma contained, on average, several copies of EBV-related DNA per cell. Despite an extensive survey of the patient, no immune deficit was detected. Interpretation of the literature with the results of this case suggest that this instance of primary cerebellar LG arose as a consequence of an unusual EBV-associated B-cell lymphoproliferation. It is suggested that EBV may be a significant factor in the initiation of the abnormal proliferations of T-cells or B-cells reported in this disorder.

B-Lymphocytes↗
PubMed1992

ME491 melanoma-associated glycoprotein family: antigenic identity of ME491, NKI/C-3, neuroglandular antigen (NGA), and CD63 proteins.

BACKGROUND: Numerous monoclonal antibodies (MAbs) have been produced to antigens found in human melanomas. Three of the best characterized melanoma antigens include the melanoma-associated glycoproteins (MAGs) defined by two reagent families--the ME491 family (including ME491, 8-1H, and 8-2A) and the NKI/C-3 family (including NKI/C-3 and NKI/black-13)--as well as the neuroglandular antigen (NGA) defined by MAbs LS59, LS62, and LS140. These three antigens have significant similarities in tissue distribution, biosynthesis, and structure. The ME491 MAG has been cloned, mapped, and sequenced. Numerous non-melanoma-associated proteins (Sm23, CO-029, R2, TAPA-1, CD9, CD37, CD53, and CD63) have recently been shown to have significant homology to this sequence. PURPOSE: We conducted this study to investigate the similarity between the two MAG antigens and NGA. METHODS: Several reagents defining the three different melanoma antigens were compared, using competition immunoprecipitation, immunoassay, and inhibition radioimmunoassay techniques. RESULTS: Immunoassay experiments show that MAbs defining the three melanoma antigens bind to affinity-purified ME491 antigen and inhibit each other from binding in an inhibition radioimmunoassay. Competition immunoprecipitation experiments demonstrate that the ME491 and NKI/C-3 antibodies bind to NGA. Rabbit anti-ME491 idiotype serum recognizes determinants shared by NKI/C-3 and the anti-NGA MAbs. A competition immunoprecipitation experiment also confirms the identity of CD63, as defined by MAb RUU-SP 2.28, with the three melanoma antigens. CONCLUSION: These data indicate that the MAGs defined by ME491 and NKI/C-3 as well as the anti-NGA antibodies are epitopes of the same molecule, which is identical to CD63 by both immunochemical and molecular genetic investigations. IMPLICATIONS: Our results indicate that the data obtained in studies of these three melanoma antigens may be pooled, and we propose that the molecule recognized by these reagents be classified as CD63.

Amino Acid Sequence↗
PubMed1992

Varicella embryopathy.

Varicella embryopathy is a rare entity afflicting infants born to mothers who have contracted varicella during the first 20 weeks of pregnancy. The teratogenicity of varicella has not been established from epidemiologic studies, but isolated case reports describe characteristic malformations following early maternal infection. We describe a male neonate delivered at 40 weeks' gestation to a 26-year-old grava 2, para 2 mother who developed varicella during the first trimester. The infant lived 7 days and died of bronchopneumonia. At postmortem examination there was growth retardation, multiple cicatricial skin lesions, flexion contractures of all major joints, hypoplastic right diaphragm, bilateral hydroureters and mucosal fibrosis of the trachea, as well as intestinal fibrosis and colonic stricture. The brain contained areas of cystic necrosis involving the frontal, parietal, temporal, and occipital lobes, with generalized ventriculomegaly. The midbrain, pons, and medulla were hypoplastic. There was denervation atrophy of muscles of the lower limbs and loss of dorsal root ganglia as well as of neurons of the anterior horn of the spinal cord. The cerebral white matter was degenerated, with proliferation of reactive astrocytes. Chorioretinitis was not observed. Immunocytochemical stains using two commercially available antivaricella antibodies were negative in all tissues examined. The sporadic nature and pathogenesis of the varicella embryopathy, which may have been caused by focal defects in the fetal T-cell immune response, are discussed.

Abnormalities, Multiple↗
PubMed1991

Granular cell neoplasm of the extrahepatic biliary tree: morphological, ultrastructural, and immunohistochemical study and review of the literature.

A recent case of a biliary granular cell tumor of the cystic duct prompted a literature review and an extensive pathological examination of the tumor in question. A total of 44 cases have been described mostly in black females. Most cases present with biliary symptoms, and simple surgical resection allows complete control of this benign condition. Granular cell tumors are most likely derived from neural crest cells.

Adult↗
PubMed1991

Signet-ring chondrosarcoma: a new morphologic entity.

A 65-year-old, otherwise healthy white man presenting with an asymptomatic anterior chest wall mass diagnosed from a routine preoperative chest x-ray is reported. A fine needle aspirate of the mass was initially interpreted as a metastatic adenocarcinoma with prominent "signet-ring" features, but ultrastructural study of the cell block later suggested a chondrosarcoma. The resected surgical specimen confirmed the diagnosis of a grade 2 chondrosarcoma, with most of the tumor cells containing a large, clear, single vacuole shown to be lipid. The positive immunostaining for vimentin and S-100 as well as the ultrastructural appearance confirmed the diagnosis of a chondrosarcoma. Flow cytometric DNA analysis of the tumor on two separate occasions documented a very large aneuploid cell population (50% to 60%) which, when interpreted with the histologic appearance, suggested an aggressive tumor. This case illustrates the first published example of a "signet-ring" chondrosarcoma.

Aged↗
PubMed1991

Granulocytic sarcoma of the ovary. An unusual case presentation.

We report an unusual occurrence of granulocytic sarcoma presenting as an ovarian mass in a 46-year-old woman with a history of dysplastic nevus syndrome. During workup of the ovarian mass, the diagnosis of acute myelogenous leukemia was made. A fine-needle aspirate of the ovarian mass showed granulocytic sarcoma. The patient died of complications of the acute leukemia a short time later. A postmortem examination was performed, which confirmed the nature of the ovarian mass as a granulocytic sarcoma. Material was obtained for flow cytometry, immunohistochemical and histochemical studies, and electron microscopy. Ploidy analysis of the tumor showed it to be diploid with an S phase of 4.8% and a G2 + M ratio of 0.5%. To our knowledge, there is only one previous report of a primary ovarian presentation of granulocytic sarcoma, and only four cases in which granulocytic sarcoma was diagnosed by fine-needle aspiration cytology. The association between dysplastic nevus syndrome and acute myeloid leukemia in this case is discussed with reference to a review of the metachronous association between melanoma and leukemia as described in the literature.

Biopsy, Needle↗
PubMed1990

Human papillomavirus type 16 associated with oral squamous carcinoma in a cardiac transplant recipient.

Human papillomavirus type 16 (HPV 16) has been associated with a variety of squamous carcinomas, particularly those involving the anogenital tract. The authors report the development of an oropharyngeal carcinoma in a 43-year-old man approximately 20 months after cardiac transplantation while he was on a maintenance regimen of cyclosporine A and prednisone. The carcinoma was resistant to treatment, and he died of complications related to metastatic disease 3 years posttransplantation. Molecular biologic studies using nonisotopic-labeled viral DNA probes were done. In situ hybridization demonstrated the presence of HPV 16 DNA in the tumor cells. DNA dot blot analysis confirmed the presence of multiple copies of HPV 16 DNA within the tumor cells and their absence from adjacent normal-appearing tissue. Southern blot analysis suggested that the HPV 16 DNA was integrated into the tumor cell genome. With increasing recognition of the carcinogenicity of HPV type 16 infection, a role for this virus in the development of squamous cell malignancies in immunosuppressed organ transplant recipients is likely to be noted with increasing frequency.

Adult↗
PubMed1990

Biosynthesis, glycosylation and intracellular processing of the neuroglandular antigen, a human melanoma-associated antigen.

Neuroglandular antigen (NGA) was identified as a human melanoma-associated antigen by a panel of murine monoclonal antibodies of both IgG2a (LS62, LS76, LS159) and IgG1 (LS113, LS140, LS152) subclasses, developed in this laboratory (L. Sikora, A. Pinto, D. Demetrick, W. Dixon, S. Urbanski, and L. M. Jerry, Int. J. Cancer, 39: 138-145, 1987). Monoclonal antibody LS62 was used to immunoprecipitate NGA from radiolabeled cultured melanoma cells, and it behaved as a heterogeneous glycoprotein "smear" on sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis (Mr 29,000-70,000). Radioactive pulse-chase time course experiments using human melanoma cells cultured in the presence or absence of inhibitors of protein glycosylation showed that the antigen consisted of a core protein with a molecular weight of 22,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This molecule was modified by the addition of at least three N-linked oligosaccharide side chains (as revealed by limited N-glycanase digestion) to give a precursor form with a molecular weight of approximately 34,000. Subsequent processing steps yielded a heterogeneous family of glycoproteins with varying amounts of covalently attached carbohydrate. Much of this heterogeneity in both molecular weight and pI (as revealed by two-dimensional electrophoresis) could be removed by treatment of the antigen with neuraminidase, suggesting heavy sialylation of the glycoprotein. NGA could be detected on the surface of melanoma cells by fluorescence-activated cell sorter analysis, surface radioiodination, and, as previously shown, immunoperoxidase staining. However, there was a larger intracellular pool of the molecule and the antigen was rapidly released into the culture supernatant. The function of NGA remains unknown but its elevated expression in transformed melanocytes have prompted this characterization to understand its biochemical nature and relation to other melanoma-associated antigens.

Antibodies, Monoclonal↗
PubMed1990

Isolation and characterization of a heterodimeric surface antigen on human melanoma cells and evidence that it is the 4F2 cell activation/proliferation molecule.

Murine monoclonal antibody (MAb) LS109 was one of a series of MAbs produced by hyperimmunization of mice with detergent extracts of pooled melanoma cell lines and metastatic melanoma patient tumors. ELISA screening of extracts of individual cultured melanoma cell lines and single patient tumors with MAb LS109 gave an interesting pattern of reactivity. The antibody was strongly positive with some of these extracts, yet negative or weakly positive with others. In addition, there was strong reactivity with a restricted set of normal necropsy tissues and certain non-melanoma tumor extracts. Taken together, our data suggest that MAb LS109 recognizes a normal differentiation antigen which is perhaps aberrantly expressed or over-produced during certain stages of melanoma tumor progression. The antigen recognized by LS109 is a heterodimeric surface glycoprotein molecule, consisting of an 89-kDa "heavy" chain linked by disulfide bonds to an 83-kDa "light" chain. Under non-reducing SDS-PAGE conditions, the intact dimer migrates with an Mr of approximately 140kDa. The 89-kDa component appears to be heavily N-glycosylated whereas the 38-kDa component has little, if any, covalently attached carbohydrate. Our data show the biosynthesis, glycosylation and turnover of the LS109 antigen, as well as evidence of its surface localization. In addition, evidence is presented that the LS109 antigen is identical to the 4F2 cell activation/proliferation molecule previously described on a variety of normal and neoplastic cells.

Animals↗