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Biomedical subjects

V E Miller

Publications and source records attributed to V E Miller.

13 recordsLinked to original sources
PubMed1996

Axonal origin and purity of growth cones isolated from fetal rat brain.

The investigation of the molecular properties of nerve growth cones depends to a significant degree on their isolation from fetal brain in the form of 'growth cone particles' (GCPs). The availability of markers for developing axons and dendrites, as well as glial cells, has made it possible to characterize the GCP fraction in much greater detail than before and to optimize its yield. Marker analyses show that a member of the N-CAM family (5B4-CAM), synaptophysin, and especially GAP-43 and non-phosphorylated tau, are enriched in the GCP fraction. In contrast, MAP2 and, particularly, glial fibrillary acidic protein and vimentin are fractionated away from GCPs. Furthermore, GCP yield can be doubled relative to the original procedure, without compromising purity, by raising the sucrose concentration of the fractionation gradient's uppermost layer. The results indicate that GCPs are highly purified growth cone fragments with very little glial contamination, and that they are primarily of axonal origin.

Animals↗
PubMed1994

Increased salivary exoglycosidase activity during critical illness.

Exoglycosidases remove peripheral monosaccharides from oligosaccharides and hence are capable of altering respiratory epithelial cell surface carbohydrates. We obtained saliva and tracheal secretions from 34 critically ill patients and saliva from 23 healthy subjects. Compared with the normal subjects, the ill patients had large amounts of mannosidase, fucosidase, hexosaminidase, and sialidase activity. Sialidase increased adherence of several gram-negative bacteria to epithelial cell monolayers and pure glycoproteins. Pretreatment of glycoproteins with some of the patients' saliva samples also increased bacterial adherence to the glycoproteins. We conclude that respiratory tract exoglycosidase activity increases during critical illness. By altering normal cell surface carbohydrates, exoglycosidases may facilitate bacterial adherence and respiratory tract colonization.

Bacterial Adhesion↗
PubMed1993

Detection of tumour necrosis factor alpha and interleukin-1 beta in the rheumatoid osteoarthritic cartilage-pannus junction by immunohistochemical methods.

During inflammation the rheumatoid synovial membrane is invaded by a number of different cell types. When activated most of these cells produce cytokines including tumor necrosis factor alpha (TNF alpha) and interleukin-1 beta (IL-1 beta). These cytokines are believed to stimulate production of degradative enzymes and disturb the equilibrium between such enzymes and their inhibitors resulting in tissue damage. In this study we investigated the localisation of TNF alpha and IL-1 beta at the cartilage-pannus junction (CPJ). Here, cytokines are well placed to influence the integrity of articular cartilage. Tissue was derived from advanced rheumatoid (RA) and, as a comparison, osteoarthritic (OA) joints at the time of replacement surgery (arthroplasty). Antibody staining of fixed serial sections of tissue localised cells that were associated with IL-1 beta and TNF alpha. Cell markers for macrophages and endothelial cells were included to provide positive identification of the cytokine-associated cells. Analysis of these sections revealed that both TNF alpha and IL-1 beta were associated with macrophages, particularly those in the synovium overlying cartilage (pannus) and endothelial cells. Positive staining was seen at the CPJ in RA and in similarly located tissue in OA. The similar distribution of cytokines in OA was unexpected even if the overall numbers of tissue and infiltrating cells in the CPJ were different in the two diseases. This highlights the possible role played by endogenous inhibitors [1, 2] in influencing the degree of cytokine activity necessary to explain the different pathogenic mechanisms in RA and OA.

Adult↗
PubMed1992

Early viral brain invasion in iatrogenic human immunodeficiency virus infection.

We report a 68-year-old man who received an IV inoculation of WBCs for an indium radionuclide scan containing 600 to 700 tissue culture infectious doses of human immunodeficiency virus type 1 (HIV-1) from an HIV-1-infected individual. The recipient immediately received zidovudine, then was switched to dideoxyinosine and interferon-alpha, but died of hepatorenal syndrome and hepatic encephalopathy 15 days later. HIV-1 cultures were positive from the recipient's blood on day 14 but not days 0, 1, and 8. At autopsy, cultures of parietal lobe isolated HIV-1. HIV-1 nucleic acid was present in several brain areas, but not in several other organs, by two independent laboratories using the polymerase chain reaction. The brain showed mild perivascular cuffing and a mild lymphocytic meningitis, but there was no evidence of glial nodules, giant cells, or white matter abnormalities. HIV-1 pg41 viral antigen was seen by immunoperoxidase staining in rare infiltrating cells within perivascular and subpial spaces. Thus, HIV-1 was isolated from brain 15 days after mistaken HIV-1 inoculation and 1 day after virus was first recovered from blood.

Aged↗
PubMed1991

Regulated plasmalemmal expansion in nerve growth cones.

To study the mechanisms underlying plasmalemmal expansion in the nerve growth cone, a cell-free assay was developed to quantify membrane addition, using ligand binding and sealed growth cone particles isolated by subcellular fractionation from fetal rat brain. Exposed versus total binding sites of 125I-wheat germ agglutinin were measured in the absence or presence of saponin, respectively, after incubation with various agents. Ca2(+)-ionophore A23187 in the presence of Ca2+ increases the number of binding sites (Bmax) but does not change their affinity (KD), indicating that new receptors appear on the plasma membrane. Similarly, membrane depolarization by high K+ or veratridine significantly induces, in a Ca2(+)-dependent manner, the externalization of lectin binding sites from an internal pool. Morphometric analysis of isolated growth cones indicates that A23187 and high K+ treatment cause a significant reduction in a specific cytoplasmic membrane compartment, thus confirming the lectin labeling results and identifying the plasmalemmal precursor. The isolated growth cones take up gamma-amino-butyric acid and serotonin, but show no evidence for Ca2(+)-dependent transmitter release so that transmitter exocytosis is dissociated from plasmalemmal expansion. The data demonstrate that plasmalemmal expansion in the growth cone is a regulated process and identify an internal pool of precursor membrane.

Animals↗
PubMed1990

[A method of determining heparin in blood plasma based on its antithrombin activity].

The suggested method for measuring blood plasma heparin is based on heparin ability to enhance antithrombin activity of antithrombin III (AT-III), the major Xa and thrombin inhibitor. The method consists in measurement of blood plasma AT-III activity in the presence and absence of protamine sulfate that destroys the heparin--AT-III complex. Heparin content in U/ml is determined from the difference in the activities of heparin--AT-III complex and AT-III proper activity represented on the calibration curve. The method is sufficiently sensitive, it permits registration of heparin concentrations in a wide band (from 0.01 U/ml to 0.75 U/ml of plasma).

Antithrombin III↗
PubMed1986

A phenyl-beta-galactoside-specific monoclonal antibody reactive with murine and rat NK cells.

The phenyl-beta-galactoside (phi-beta-gal)-specific monoclonal antibody (mAb) 49H.8 cross-reacts with the terminal disaccharide structure of the asialo GM1 (AGM1) molecule. It was found to react with phi-beta-gal determinants on murine and rat splenic natural killer (NK) cells, as measured by complement depletion studies. Flow cytometric analysis identified the antigen on two IL 2-dependent cloned murine NK cell lines and the rat large granular lymphocyte leukemia RNK. We have compared the 49H.8 reactivity to that of anti-AGM1 antisera (alpha-AGM1) on NK cells and a panel of NK related killer cells, including bone marrow-derived killer cells, lymphokine-activated killer cells (LAK), and anomalous killer cells (AK). We found that the 49H.8 specificity closely paralleled that of alpha-AGM1. When tested against Con A-reactive T cells, the 49H.8 mAb was less reactive than the alpha-AGM1, indicating that it may be a more specific marker for splenic NK populations than the alpha-AGM1.

Animals↗
PubMed1985

Hand-held real-time breast sonography.

The results of real-time hand-held sonographic breast examinations on 86 patients are presented. The technique is described in detail. Sonography was found to be a useful adjunct to the x-ray mammogram in three groups of patients: (1) patients with dense breasts and localized symptomatology or a suspicious area on x-ray mammogram; (2) patients with nonpalpable abnormalities discovered on x-ray mammogram; and (3) patients with palpable masses considered indeterminate on x-ray mammogram. The examination was also found useful for guiding needle aspiration biopsies, in patients with persistent nipple discharge, and in those with breast prostheses. Advantages of the hand-held real-time technique include supine positioning, the ability to flexibly orient the probe, improved resolution due to higher frequency transducers and the lack of compounding, and the ability to vary the amount of compression to assess tissue compliance and fixation. The disadvantage of decreased resolution in the near field can be overcome by attaching a detachable water-path step-off device to the transducer. Geometric distortion from the pressure of the transducer was not believed to be a problem. Hand-held sonographic technique is useful when attention can be directed to a specific area of the breast. The additional information provided results in fewer equivocal interpretations of the x-ray mammogram; however, it should not be used as a substitute for routine mammography.

Adult↗
PubMed1985

Pulsed Doppler duplex sonography and CT of portal vein thrombosis.

Five patients with partial or complete portal vein thrombosis were examined by both computed tomography (CT) and pulsed Doppler duplex scanning. Duplex scanning correctly identified portal vein thrombosis in all five. Duplex sonography may be the preferred technique to detect and follow portal vein thrombosis because of lower cost, lack of need for intravenous contrast material, and easier availability for multiple follow-up examinations.

Adult↗
PubMed1983

Murine natural antitumor antibodies. III. Interferon treatment of a natural killer-resistant lymphoma: augmentation of natural antibody reactivity and susceptibility to in vivo natural resistance.

Treatment of a natural killer cell-resistant (NKR) DBA/2 lymphoma with L-cell interferon (IFN) enhanced its reactivity to serum natural antibody in vitro in cytolysis and absorption studies and increased the in vivo acquisition of natural and antitumor antibody in the peritoneal cavity. The IFN effects were both time- and dose-dependent. In vitro IFN-treated, [131I]5-iodo-2'-deoxyuridine-labeled tumor cells, when injected ip into normal syngeneic mice, were more rapidly eliminated than were untreated control cells. IFN treatment of the NKR tumor decreased "cold-target" inhibition of NK lysis and did not alter binding or lysis by macrophages. These findings indicated that the enhancement of natural resistance to the IFN-treated tumor did not involve NK cells or macrophages and suggested that IFN may enhance host antitumor resistance by increasing tumor reactivity to antibody.

Animals↗
PubMed1981

Natural resistance to tumors is a heterogeneous immunological phenomenon. Evidence for non-NK cell mechanisms.

The contribution of natural killer (NK) cells to natural antitumor resistance (NR) in syngeneic DBA/2 mice was examined. Subclones from two NK-resistant tumors, P815 and L5178Y, were selected for tumorigenicity in NR assays measuring the tumor frequency of threshold doses and the elimination of 131IUdR-labelled cells. In vivo variation in sensitivity to NR did not correlate with in vitro NK cytolysis for these clones, but did for a third pair of clones from the SL2 lymphoma selected on the basis of sensitivity or resistance to NK lysis. In another series of experiments it was found that a decrease in NK cytolysis of the (NK-sensitive) SL2-5 lymphoma in aged DBA/2 contrasted with an increased rate of elimination and lower tumor frequency, suggesting that the ontogeny of these phenomena was not related. In addition, while interferon treatment of the (NK-sensitive) SL2-5 produced a corresponding decrease in susceptibility to NK cytolysis in vitro and a reduction in the in vivo elimination of 131I-labelled cells, tumor of the NK-resistant phenotype, interferon-treated in the same way, remained NK-resistant and was more rapidly eliminated. The failure to observe correlative changes in NK cytolysis associated with heterogeneity in tumorigenicity and with age-related or interferon-induced changes in NR suggest that NR cannot be due solely to an NK effector mechanism.

Animals↗