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Biomedical subjects

D L Baker

Publications and source records attributed to D L Baker.

At least 55 records · Page 3Linked to original sources
PubMed1992

Intraoral infantile hemangiopericytoma: literature review and addition of a case.

A rapidly growing neoplasm in the buccal mucosa of a 4-month-old baby was excised. By light and electron microscopy the neoplasm had features that were similar to those described in infantile hemangiopericytoma, a rare neoplasm of vascular origin. By light microscopy the neoplasm was multilobular with highly proliferating round to spindle-shaped cells interspersed with numerous vascular spaces. Ultrastructurally, round to elongated cells with short processes, pinocytotic vesicles, reduplicated basal lamina, and basal lamina-like material were identified. Immunohistochemically the cells were weakly positive with antibodies to vimentin, focally positive with HHF-35, a smooth-muscle cell antibody, negative with antibodies to S-100 protein, T-200, neuron-specific enolase, neurofilaments, desmin, and cytokeratins 35BH11 and 34BE12. Blood vessels were positive with Ulexeuropaeuslectin, but tumor cells were negative. Reticulin stain decorated a delicate network of fibrils surrounding tumor cells and vascular spaces. Clinically the neoplasm did not recur and the baby has been disease free for more than 26 months. The difficulty of the histologic diagnosis of this neoplasm is discussed and the literature is reviewed, with special emphasis on lesions occurring in the oral cavity.

Diagnosis, Differential↗
PubMed1992

Long-term stability after inferior maxillary repositioning by miniplate fixation.

Nineteen patients underwent Le Fort I osteotomy and inferior maxillary repositioning. Miniplates were used to maintain the maxilla in its new position. The patients were followed from 12 to 58 months, postoperatively. Fourteen patients were considered to be stable over the long term. Five patients had a long-term relapse of more than 30%. A tendency towards greater relapse was seen in patients with more than 5 mm inferior repositioning, and in patients who had concurrent segmental osteotomies of the maxilla. In spite of the use of miniplates, there continues to be an element of unpredictability with regard to vertical relapse after inferior maxillary repositioning, and this may be related to soft-tissue influences.

Adolescent↗
PubMed1991

Nerve growth factor receptor expression in peripheral and central neuroectodermal tumors, other pediatric brain tumors, and during development of the adrenal gland.

Nerve growth factor (NGF) is important to the survival, development, and differentiation of neurons. Its action is mediated by a specific cell surface transmembrane glycoprotein, nerve growth factor receptor (NGFR). In this study, NGFR expression by human fetal and adult adrenal medullary tissue, peripheral nervous system (PNS) neuroectodermal tumors (neuroblastoma, ganglioneuroblastoma, ganglioneuroma), pediatric primitive neuroectodermal tumors (PNETs) of the central nervous system (CNS), and CNS gliomas was examined by an immunohistochemical technique. Sixty-nine tumors in total were probed in this manner. Nerve growth factor receptor immunoreactivity was confined to nerve fibers and clusters of primitive-appearing cells in the fetal adrenal, and to nerve fibers and ganglion cells of the adult adrenal medulla; adrenal chromaffin cells were negative. In PNS neuroectodermal tumors, there was NGFR expression in tumor cells of 6 of 11 neuroblastomas and 6 of 6 ganglioneuroblastomas or ganglioneuromas. Thirteen of thirty-five CNS PNETs showed NGFR positivity. In most CNS PNETs, NGFR was restricted to scattered single or small groups of cells, but two tumors with astroglial differentiation showed much more extensive immunoreactivity. Most astrocytomas (11 of 14) and all ependymomas (3 of 3) were intensely NGFR positive.

Adolescent↗
PubMed1990

Human central nervous system primitive neuroectodermal tumor expressing nerve growth factor receptors: CHP707m.

A primitive neuroectodermal tumor (PNET) presented as a cerebral hemispheric mass in a 33-year-old man. Bone marrow metastases were discovered 11 months later. A cell line (CHP707m) was derived from these metastases. In culture, the cells showed features of neuronal differentiation, forming short neurites and synthesizing low-molecular-weight neurofilament protein. Northern blotting showed the tumor cells express nerve growth factor (NGF) receptor messenger RNA, and fluorescence-activated cell-sorting demonstrated NGF receptors on the cell surface. Western blotting showed CHP707m NGF receptors are truncated. The receptors are functional; they bind iodine 125-labeled mouse NGF with an affinity of 1.6 x 10(-9) M, and short-term treatment with NGF induces expression by the tumor cells of the proto-oncogene, c-fos. Although CHP707m is the first central nervous system PNET cell line proven to express NGF receptors, immunohistological survey of tissue sections prepared from human central nervous system PNETs showed that 13 of 35 contained NGF receptor-positive tumor cells. Thus, more than one-third of such tumors might be responsive to the effects of NGF.

Adult↗
PubMed1990

The neuroendocrine and neural profiles of neuroblastomas, ganglioneuroblastomas, and ganglioneuromas.

To establish the neuroendocrine and neural features of peripheral neuroblastic tumors, a prospectively collected group of 12 neuroblastomas (NB), 2 ganglioneuroblastomas (GNB), and 4 ganglioneuromas (GN) was probed with a panel of monoclonal antibodies (MAbs) to neuroendocrine and neural antigens. All tumors expressed the pan-neuroendocrine markers synaptophysin and chromogranin A. They also showed extensive expression of neuronal antigens, ie, of each of the neurofilament (NF) triplet proteins and of the microtubule-associated proteins (MAPs) MAP2 and tau-protein. However, only in the GNBs and GNs was the pattern of NF phosphoisoforms relatively mature. In the latter tumors glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP) could be demonstrated as well, suggesting the presence of nonmyelinating and myelinating Schwann cells, respectively. The glial markers did not colocalize with the neural markers. On the basis of these data, it was concluded that all peripheral neuroblastic tumors manifest molecular characteristics of neuroendocrine cells and of neurons. The latter were most developed in GNBs and GNs, in which they were accompanied by Schwann cell differentiation in a separate population of cells. The above-outlined neuronal profile of peripheral neuroblastic tumors, including NBs, distinguishes this group of tumors from the much-less neuronally differentiated primitive neuroectodermal tumors of the central nervous system.

Abdominal Neoplasms↗
PubMed1989

Analysis of nerve growth factor receptor expression in human neuroblastoma and neuroepithelioma cell lines.

A series of 22 neuroepithelioma and neuroblastoma cell lines were screened for expression of nerve growth factor receptor (NGFR) by flow cytometry, Western blotting, and Northern blotting. All 5 neuroepithelioma cell lines expressed cell surface NGFR, with 30-69% of cells NGFR positive, but the 17 neuroblastoma cell lines tested had a smaller percentage of cell surface NGFR-positive cells (0-21%) and 10 lines were completely lacking cell surface NGFR. SY5Y, a variant line with a neuronal phenotype derived from neuroblastoma line SKNSH, expressed much more NGFR than SHEP, a variant line with an epithelial-like phenotype also derived from SKNSH. By Western blotting, the Mr approximately 69,000 NGFR band was detected for all four neuroepithelioma cell lines tested but was visible for only 8 of 15 neuroblastoma cell lines tested. The band was most intense for neuroepithelioma cell lines SKNMC and TC32. For these two lines, a Mr approximately 56,000 and a Mr approximately 60,000 band were also detected. By Northern blotting, all three neuroepithelioma cell lines tested were positive for the 3.8 kilobase NGFR mRNA, but only 8 of 15 neuroblastoma cell lines were positive. Neuroepithelioma cell line TC32 and neuroblastoma cell line GICAN had the strongest expression of NGFR mRNA. These results demonstrate that NGFR is a biological marker for neuroepithelioma and that NGFR expression is heterogeneous for neuroblastoma cell lines. This series of neural cell lines differing in NGFR expression will be useful for future studies of regulation of NGFR expression and neuronal differentiation.

Antibodies, Monoclonal↗
PubMed1988

Rapid excretion of gallium-67 isotope in an iron-overloaded patient receiving high-dose intravenous deferoxamine.

A 23 year-old black male with homozygous sickle cell disease (Hb SS disease) and transfusional iron overload was admitted for evaluation of response to intravenous deferoxamine (DFO) therapy. Soon after admission, the patient suffered an intraventricular hemorrhage and during his subsequent hospitalization developed a persistent fever of undetermined origin (f.u.o.). Included in the diagnostic evaluation of fever was a gallium 67 scan (Ga-67), which was initially nondiagnostic because of Ga-67 citrate's preferential chelation by DFO. After DFO was discontinued, a repeat scan demonstrated a lesion above the left kidney. To our knowledge the unusual interaction in vivo of DFO with Ga-67 citrate has not been reported in the clinical literature. With the anticipated increased use of chelation therapy for patients with transfusional iron overload, this interaction may be encountered more frequently. DFO should be discontinued before the use of Ga-67 scanning in this clinical situation, or an alternative isotopic scan, such as indium-labelled white cells, should be considered.

Adult↗
PubMed1984

Cat eye syndrome owing to tetrasomy 22pter leads to q11.

A case of tetrasomy 22pter leads to q11 with ocular hypertelorism, downward slanting palpebral fissures, total anomalous pulmonary venous return, and anal atresia is described. The phenotypic variability of the cat eye syndrome is emphasised along with the need for categorisation of these patients according to well characterised cytogenetic findings.

Abnormalities, Multiple↗
PubMed1984

Application of the MAST Immunodiagnostic System to the determination of allergen-specific IgE.

The MAST Immunodiagnostic Test System was developed to provide a comprehensive, simple means for the in vitro measurement of multiple antigens or antibodies. The first commercial application of the MAST system incorporates several novel features for cost-effective diagnosis of IgE-mediated allergy in a clinical laboratory or a physician's office. The basis of the MAST system is a unique analytical test chamber, which contains cellulose thread as the solid-phase matrix and allows multiple test results from a single assay. This test chamber incorporates both positive and negative controls and requires no volume-dependent pipetting steps. Immunographic exposure onto high-speed Polaroid instant film allows for quantifying results with an automatic recording infrared-transmittance densitometer. Test results are easily interpreted by using a patient test record provided with the system. The MAST system greatly simplifies testing for allergen-specific IgE, while retaining specificity and sensitivity. Currently, with the MAST system one can simultaneously measure picomoles of allergen-specific IgE in up to 35 different allergen classes. In addition to allergy testing, the MAST technology is applicable to other immunodiagnostic profiles.

Antibody Specificity↗
PubMed1976

The possible pathogenesis of gingival recession. A histological study of induced recession in the rat.

Stages in the pathogenesis of gingival recession were observed in rats in which pocketing had been induced by replacement of natural incisors with dental implants. Suitable conditions were thus created on the palatal aspect of the implant sockets for recession to occur. The recession process was examined at intervals by taking transverse serial sections. In the epithelial and connective tissues deep to the receding margin, morphological changes were seen which apparently lead to cleft formation and recession. These appeared to be associated with mononuclear cell infiltration of the connective tissue. The study suggests that gingival recession involves a localized inflammatory process which causes breakdown of connective tissue and leads to proliferation of the epithelium into the site of connective tissue destruction. Proliferation of the epithelial cells into the connective tissue brings about a subsidence of the epithelial surface, which is manifest clinically as recession.

Animals↗