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Biomedical subjects

A W Martin

Publications and source records attributed to A W Martin.

At least 37 records · Page 2Linked to original sources
PubMed1991

Dietary management of swallowing disorders.

Two major concerns in the dietary management of the dysphagic patient are to maintain adequate nutrition and to ensure safety during oral feeding. Dysphagic patients require modifications of standard hospital diets. Kitchen or nursing staff must remove from standard diet trays solid foods and liquids that pose swallowing hazards. Training kitchen and nursing staff and removing food are time consuming. It is also hazardous if certain foods are served to dysphagic patients through error or lack of knowledge. In addition, there is risk of inadequate nutrition when food is removed from trays. This paper proposes a four-level diet plan for patients who have difficulty swallowing solids and liquids. These diets gradually advance for patients undergoing treatment to improve swallowing function. The proposed diets save time for kitchen and nursing staff, reduce the risk of aspiration among patients, and serve as models for families as they prepare for discharge and meal planning at home. Diet guidelines are based on recommendations of the American Dietetic Association.

Deglutition Disorders↗
PubMed1991

Multidrug resistance phenotype associated with selection of an aminopterin resistant dog kidney cell line.

A determination of the mechanisms of drug resistance in tumour cells is important for developing strategies to combat such resistance in persons receiving chemotherapy. This report describes a combined cellular, biochemical, and molecular analysis of a dog kidney cell line selected for resistance to increasing levels of the hydrophilic antifolate, aminopterin. Three distinct drug resistance phenotypes were observed in cells exhibiting high levels of aminopterin resistance. Two of these phenotypes were decreased aminopterin accumulation and increased levels of dihydrofolate reductase specific activity. The third drug resistance phenotype was noted initially as cross resistance to a variety of hydrophobic drugs indicating multidrug resistance. Biochemical assays demonstrated reduced accumulation of the hydrophobic fluorescent drug daunorubicin and of 3H-colchicine in the aminopterin resistant cells. These results were then correlated with increased levels of the multidrug resistance (mdr) gene product, P-glycoprotein, and mdr mRNA levels in the aminopterin resistant cells. However, experiments designed to prove a role for expression of the mdr gene in providing a degree of aminopterin resistance were unsuccessful. It is concluded that aminopterin selection in these dog kidney cells resulted in expression of at least three distinct drug resistance phenotypes and that one of these phenotypes, multidrug resistance, represented a secondary response to the aminopterin selection.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1991

Cerebral tissue pulmonary embolization due to head trauma: a case report with immunohistochemical confirmation.

Pulmonary embolization of cerebral tissue as the result of severe head trauma is an uncommon, if not rare, phenomenon, and few cases have been reported in the literature. The authors discuss the case of a 51-year-old male who died six days after suffering extensive head trauma in a motor vehicle collision. At autopsy, white-gray emboli were found in several subsegmental pulmonary arteries. The results of histologic examination with the hematoxylineosin stain gave the impression that the emboli were necrotic cerebral tissue; however, routine special stains for neural tissue produced inconclusive results. Immunohistochemical staining of the emboli with monoclonal mouse anti-human neurofilament protein (Dako Corp., Carpinteria, California) confirmed the cerebral nature of the emboli. To the authors' knowledge, this is the first reported case of pulmonary embolization of cerebral tissue confirmed by immunohistochemistry.

Accidents, Traffic↗
PubMed1990

Chromosome abnormalities in human epithelial ovarian malignancies.

Karyotypic analysis of tumor specimens from 29 patients with untreated epithelial ovarian carcinoma was performed at the University of Kentucky Medical Center. Twenty-three of the twenty-nine tumors had adequate cells for analysis. Seventeen of these tumors exhibited chromosome abnormalities. Chromosome alterations were complex, with an average of seven different abnormal chromosomal patterns per tumor (range 2-14). Chromosomes 1 and 11 were the most commonly involved, being abnormal in 89 and 83% of tumors, respectively. Chromosomes 3 and 7 were also frequently abnormal. In contrast to invasive tumors, alterations in chromosomes 1 and 11 were not seen in the two tumors of borderline malignant potential. Evidence for DNA amplification of IGF2, Ha-ras-1, and c-ets was not observed. Amplification of the c-erbB-2 oncogene was present in two tumors. These findings indicate that multiple karyotypic abnormalities occur in untreated epithelial ovarian malignancies, with chromosomes 1 and 11 being the most frequently abnormal. These data also suggest that alterations of these chromosomes may be associated with the biologically aggressive behavior of frankly invasive ovarian tumors.

Adult↗
PubMed1990

Non-Hodgkin's lymphomas of the gastrointestinal tract. An evaluation of paraffin section immunostaining.

Although the gastrointestinal (GI) tract is the most common site of primary extranodal lymphomas, the lineage of these tumors has been controversial. The authors used paraffin-reactive antibodies detecting markers of B-, T-, histiocytic, and epithelial cells to study 34 non-Hodgkin's lymphomas of the GI tract for which unequivocal frozen-section immunophenotypine was available as a control to determine whether these antibodies are reliable in the study of these tumors. Frozen-section studies revealed 31 tumors of B-cell origin and three T-cell tumors. Paraffin-reactive antibodies confirmed B-cell lineage in 28 of the 31 cases, with equivocal results in the remaining three. Only one of the T-cell lymphomas was identified in paraffin studies. Our results indicate that paraffin-reactive antibodies can reliably identify most B-cell lymphomas in the GI tract but may be unreliable in the detection of lymphomas of T-cell origin.

Adult↗
PubMed1990

The detection of Epstein-Barr virus in hairy cell leukemia cells by in situ hybridization.

Epstein-Barr virus (EBV) has been implicated in the pathogenesis of several B-cell lymphoid proliferations. Because patients with hairy cell leukemia (HCL) have a high incidence of seropositivity for EBV antigens, we studied the cells of HCL for evidence of EBV infection using in situ hybridization techniques. EBV mRNA was detected in the tumor cells in four of six cases using a radiolabeled RNA probe. Confirmatory serologic data were available in three cases in which the viral DNA was detected and in one negative case. Our results suggest that EBV infection may have a pathogenetic role in this disorder.

Adult↗
PubMed1989

Paraffin section markers for Reed-Sternberg cells. A comparative study of peanut agglutinin, Leu-M1, LN-2, and Ber-H2.

Hodgkin's disease (HD) is sometimes difficult to distinguish from non-Hodgkin's lymphomas, and a reliable marker for Reed-Sternberg and related (R-S) cells in paraffin sections would be useful. Ninety-one cases of HD with PNA, anti-Leu M1, and LN-2, and 90 cases with Ber-H2 were studied. The staining results were evaluated independently. R-S cells stained positively with one or more of the reagents in all cases. PNA staining was positive in 78 cases (85.7%); Leu M1, 63 (69.2%); LN-2, 71 (78.0%); and Ber-H2, 80 cases (88.9%). Positively stained cells were readily recognized in 71 cases (91.0%) of PNA+, 51 (80.9%) of Leu M1+, and 51 (71.8%) of LN-2+ and 71 (88.7%) of Ber-H2+ cases; the cells were found only after careful search in the remaining cases. Sixteen cases of peripheral T-cell lymphoma (large cell type, ten; mixed, five; unclassifiable, one) were also stained. Tumor cells did not stain with PNA or anti-Leu M1 in any of the 16 cases but did stain positively with LN-2 in four and with Ber-H2 in five. Thus, the detection rate of R-S cells was the highest with Ber-H2, closely followed by PNA. PNA, however, stained the largest number of R-S cells per case, and the results were least affected by the type of fixative employed. Staining of peripheral T-cell lymphoma appeared to be nil or extremely rare with PNA and Leu M1, whereas it was not uncommon with Ber-H2 and LN-2. In conclusion, to facilitate the detection of R-S cells in paraffin sections, the application of a panel of three markers, PNA, Leu M1, and Ber-H2, appears to be necessary at this point in time.

Antigens, Differentiation↗
PubMed1989

Nonsecretory multiple myeloma in a 26-year-old man with acquired immunodeficiency syndrome, presenting with multiple extramedullary plasmacytomas and osteolytic bone disease.

High grade B-cell lymphoma and leukemia have been well described in patients with the acquired immunodeficiency syndrome (AIDS). Malignant transformation of more differentiated lymphoid cells has not been well described in these patients. We report a 26-year-old man with AIDS-associated multiple myeloma, who had a highly unusual presentation and clinical course. A review of the literature indicates that monoclonal gammopathy in patients seropositive for the human immunodeficiency virus (HIV) is common. Multiple myeloma and extramedullary plasmacytomas, diseases that are extraordinarily rare in young persons, are now being reported in patients with AIDS and should be added to the list of neoplastic diseases now associated with HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Iron binding proteins and their roles in the tobacco hornworm, Manduca sexta (L.).

Manduca sexta larvae accumulate large amounts of iron during their larval feeding period. When 59Fe was fed to 5th instar larvae, it was evenly distributed among the hemolymph, gut and carcass until the cessation of feeding. By pupation 95% of the labelled iron was found in the fat body. In the adult a significant portion of this iron was found in flight muscle. Studies of the hemolymph disclosed two iron-containing proteins. The first was composed of a single polypeptide chain of 80 kD, containing one atom of iron. This protein bound ionic iron in vitro and was able to transfer this iron to ferritin when incubated with fat body in vitro. Therefore, it appeared to serve a transport function. The second protein had a molecular weight of 490 kD with subunits of 24 and 26 kD and contained 220 micrograms of iron/mg protein. Its chemical and ultrastructural characteristics were those of ferritin. These studies demonstrate the presence of both a transport protein and a unique circulating ferritin in Manduca sexta, the latter serving a storage function during development and possibly also a transport function.

Animals↗
PubMed1987

Hemoglobin C in association with hereditary persistence of fetal hemoglobin.

Hemoglobin C and hereditary persistence of fetal hemoglobin (HPFH) are an uncommon combination of hemoglobinopathies. Several tests are needed to verify this condition, among them hemoglobin electrophoresis and Kleihauer-Betke staining of a peripheral blood smear. Family studies are useful in delineating the genetics of the hemoglobinopathy but could not be performed in our case. In more confusing cases or with an unusual subtype, more extensive testing may be required. HPFH, by itself, is without clinical manifestations. It may be confused with other conditions; therefore, its presence in patients with hematologic symptoms requires more precise definition of the hemoglobin abnormality.

Adult↗
PubMed1987

Processes in formation of mucus by the body wall of Ariolimax columbianus.

The mucus secreted by the body surface of the terrestrial pulmonate slug, Ariolimax columbianus, is a variable mix of products of the giant mucous and channel cells of the skin. An in vitro sac preparation allows the study of control and products of these two cell types. Mucins in membrane-bound granules are released by the mucous cells on mechanical or electrical stimulation of the skin. The product of the channel cells is a blood ultrafiltrate, modified by reabsorption of Na+ and Cl- ions and transfer into the fluid of K+ and HCO3- ions (processes of secretion inhibited by ouabain, amiloride and furosemide; and by other epithelial blocking agents). Rates of secretion can be increased or decreased by gastropod neurotransmitters (acetylcholine, serotonin, and others), and by prostaglandin E2 and indomethacin.

Animals↗
PubMed1986

Soft tissue tumor with prominent leptomeric fibrils and complexes.

A recurrent soft tissue tumor from the groin in a 37-year-old male is described. The tumor cells contain many leptomeric structures, both fibrils and complexes, but none of the other characteristic features of striated muscle: alternating parallel thick and thin myofilaments with Z-line material. A review of one rhabdomyoma and six rhabdomyosarcomas demonstrates that leptomeric structures are present in large amounts in the rhabdomyoma but are very infrequent in only three of the six rhabdomyosarcomas. A careful search for leptomeric structures is indicated when the ultrastructural diagnosis of either rhabdomyoma or rhabdomyosarcoma is being considered.

Adult↗
PubMed1984

The channel cell of the terrestrial slug Ariolimax columbianus (Stylommatophora, Arionidae).

Studies were carried out to identify the route by which macromolecules and large volumes of fluid traverse the skin of terrestrial gastropods. Electron micrographs of the skin of the banana slug Ariolimax columbianus demonstrated that carbon particles can enter large, specialized cells and pass thence to the exterior. These cells, which are termed channel cells, range up to 500 micron in length; they reach from the external surface of the skin to deep within the subepithelial interstitium. At the light-microscope level they show a large central channel or reservoir apparently filled with homogeneous fluid; after injection of ink into the body cavity this central channel becomes ink-filled. Electron micrographs show cisternae of the smooth endoplasmic reticulum, opening from the cell surface and occasionally traversing the entire cytoplasmic layer. The neurohormone arginine vasotocin stimulates fluid and particle movement through the channel cell; this response is inhibited by norepinephrine. Fluid output is dependent on the presence of a transwall hydrostatic pressure gradient of about 7 torr or above, as well as on activation of the channel cells.

Animals↗
PubMed1984

Immunological and biological characteristics of the vasotocin-like activity in the head ganglia of gastropod molluscs.

Extracts of cerebral and pleuro-pedal ganglia from two terrestrial slugs, Ariolimax columbianus and Limax maximus, and from the marine opisthobranch, Aplysia californica, contain immunoreactivity resembling that of a vasotocin or vasopressin. Radioimmunoassays using several antisera indicate that the immunoreactivity is not due to vasotocin, vasopressin, or any other known naturally occurring neurohypophyseal peptide. Immunoreactivity of extracts on a relatively nonspecific vasopressin antiserum is well correlated with activity on antidiuretic assays on rats. Both immunoreactivity and antidiuretic activity are adsorbed onto bovine neurophysin affinity columns. Thus these extracts contain one or more peptides that closely resemble the vertebrate antidiuretic hormones, vasotocin and vasopressin, both immunologically and pharmacologically. The amounts of immunoreactivity and antidiuretic activity in ganglion extracts do not appear to change during dehydration and rehydration. Although both ganglionic extracts and vasotocin stimulate exudation of fluid across the slug body wall, the present experiments provide no evidence that the vasotocin-like material(s) in these ganglia may participate as neurotransmitters or hormones in the regulation of fluid balance. This remains an attractive hypothesis.

Animals↗
PubMed1984

A mono-sited transferrin from a representative deuterostome: the ascidian Pyura stolonifera (subphylum Urochordata).

An iron-binding protein has been found in the plasma of Pyura stolonifera. This protein has a molecular weight of about 41,000 +/- 2,000 and binds 1 mol iron/mol protein. The absorption maxima are lambda = 280 and lambda = 429 nm (E429/E280 = 0.044). Bicarbonate is bound concomitantly with high affinity and is necessary for optimal color formation at lambda = 429 nm. The protein showed a negligible exchange of iron with human apotransferrin under physiologic conditions over two hours. Upon incubation with rat reticulocytes, the protein reacts with membrane receptors for transferrins, and the protein, with its iron, is transported intracellularly where the iron is incorporated into heme. The 59Fe protein, after intravenous injection, disappears rapidly from the plasma and is excreted largely in the urine, with a substantial fraction present in the kidney and another large fraction present in the gut. These findings established the protein as a "transferrin" and support the concept that the larger transferrin molecule in vertebrates, with two iron-binding sites, resulted from a gene duplication.

Animals↗
PubMed1983

Components of mucus of terrestrial slugs (Gastropoda).

Mucous secretion by the body wall of the terrestrial slugs (Ariolimax columbianus, Arionidae; and other species) was found to involve at least three distinct stages--release of vesicles, formation of granules, and organization of strands. Mucus is stored intracellularly in membrane-bound vesicles, and these are shed intact from the mucous cells. Disruption of the vesicle membrane, with release of contents, can be effected by endogenous lytic agent(s), as well as by exogenous surfactants, lipid solvents, or hypotonic media. Thereupon 1-micron granules are released. These may be stable, or they may change to material that is finely granular or in the form of strands; the transition to strands is facilitated by shear stress exerted through the fluid containing the mucous components. Lectins organize, or are organized with, the strands, as evidenced by agglutination of erythrocytes on them. Mucous formation, as seen in the living slug, differs markedly from the one-step process of exocytosis of fluid mucus inferred from studies of mucous membranes fixed for ultrastructural investigation.

Animals↗
PubMed1981

Cytology of the renal appendages of Nautilus (Cephalopoda, Tetrabranchiata).

The renal appendages of tetrabranchiate cephalopods, Nautilus pompilius (L.) and Nautilus macromphalus (G.B. Sow.), were studied using light- and electron-microscopical methods. The appendages, homologous to the renal appendages of dibranchiate cephalopods, possess in both species a folded transporting epithelium characterized by a secreting brush border and a high content of mitochondria and lysosome-like dense bodies as well as a basal labyrinth, and are separated from the blood lacunae by a multilayered lamina basalis. In the extracellular crypt-like infoldings of the epithelium, numerous concentric stratified concrements are found. The results strengthen the hypothesis that these concrements represent mineral-storage structures only found in calcium shell-supporting species within the class Cephalopoda.

Animals↗