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J Minna

Publications and source records attributed to J Minna.

35 records · Page 2Linked to original sources
PubMed1986

Osmotic blood-brain barrier opening to IgM monoclonal antibody in the rat.

Pharmacokinetic parameters of iodinated monoclonal antibody (MAb) delivery to normal rat brain were examined. The mean cerebrovascular permeability-surface area (PA; permeability X capillary surface area) to immunoglobulin M (IgM) MAb (mol wt 1,000,000) 10 min after infusion was 0.40 X 10(-6) S-1. When osmotic blood-brain barrier (BBB) disruption is utilized, the PA increased to 8.36 X 10(-6) S-1. Neither intravenous nor intracarotid MAb administration significantly affected delivery to brain. However, osmotic BBB opening significantly (P less than 0.0005) increased MAb uptake independent of the route of administration. After BBB opening and intracarotid MAb the maximum concentration in brain at 1 h was 0.72% per gram of the total administered dose. For 6 h postdisruption, ipsilateral brain levels were 25- to 100-fold greater than in the contralateral hemisphere or nonbarrier-disrupted controls. MAb concentration in brain slightly decreased over 72 h (P less than 0.05). Antibody recovered from disrupted brain retained 90% of its immunological reactivity for at least 24 h. MAb delivery to ipsilateral brain after BBB disruption was linear over a dose of 0.5-5.0 micrograms IgM, whereas the percentage of the total administered dose remained unchanged. After osmotic treatment, barrier opening was maximal to MAb delivery for 1 min with delivery declining rapidly thereafter. The type of anesthesia used and the administration of a thyroid-blocking agent were found to affect brain MAb levels after BBB disruption.

Animals↗
PubMed1986

Heterogeneity of cell surface antigen expression of human small cell lung cancer detected by monoclonal antibodies.

Using immunohistochemistry, radiobinding, and indirect immunofluorescence assays, seven distinct cell surface antigens, detected by monoclonal antibodies, were analyzed for the degree of homogeneity or heterogeneity of antigen expression on a panel of human small cell lung cancers. The panel included 7 tumors taken directly from patients, 21 established cell lines (9 of which were derived from different metastatic sites of 3 patients), and 33 clonal derivatives of 3 lines. With all assays, considerable heterogeneity of antigen expression between tumors from different patients was observed. In both fresh tumors and in cell lines, as well as in cell lines established from different metastatic sites in an individual patient, we observed intratumor heterogeneity finding antigen positive and negative cells and variation in antigenic density, by immunohistochemistry and indirect immunofluorescence assays. Antigenic expression was not cell cycle dependent. In addition, when cell lines or patient samples expressing antigen positive and antigen negative tumor cells were cloned, heterogeneity of antigenic expression was still present in the clonal lines. This suggests that either the expression of the antigen was not heritable and/or the ability to regenerate antigenic heterogeneity is an intrinsic property of the tumor cells. The heterogeneity of antigen expression on lung cancer cells has significant implications for the use of these and other monoclonal antibodies in the study and therapy of lung cancer.

Antibodies, Monoclonal↗
PubMed1982

Topographic antigenic determinants recognized by monoclonal antibodies to sperm whale myoglobin.

Monoclonal antibodies of high affinity (approximately 10(9) M-1) for sperm whale myoglobin were studied to pinpoint the antigenic determinants with which they interact. None of 6 different monoclonal antibodies tested reacted with any of the 3 CNBr cleavage fragments which encompass the whole sequence of myoglobin, an indication that they react with determinants present only on the native structure. To identify these sites, we compared the affinities of each antibody for a series of 14 mammalian myoglobins of known sequence and similar tertiary structure. Correlation of sequence differences with relative affinities allowed us, thus far, to identify critical antigenic residues recognized by 3 of the antibodies. Two of these antibodies recognize groups of residues which are far apart in primary structure but close together in the 3-dimensional structure of the native myoglobin molecule, i.e. topographic determinants. The third antibody distinguishes 140 Lys leads to Asn plus, probably, surface residues nearby. These determinants differ from previously reported antigenic sites on sperm whale myoglobin both in that they are topographic, rather than sequential, and in that almost all the critical residues recognized by these antibodies are outside the previously reported sites. Monoclonal antibodies are sensitive to subtle changes, e.g. Glu leads to Asp, in the antigenic site.

Amino Acid Sequence↗
PubMed1981

Cell surface differentiation antigens of the malignant T cell in Sezary syndrome and mycosis fungoides.

Using a panel of monoclonal antibodies and rabbit heteroantisera, we have studied the cell surface markers of peripheral blood (PB) Sezary cells from six patients with mycosis fungoides or Sezary syndrome, disease grouped within the spectrum of cutaneous T cell lymphomas (CTCL). Furthermore, we have studied two cell lines (Hut 78 and Hut 102) derived from malignant Sezary T cells from CTCL patients. The monoclonal antibody 3A1 defines a major human PB T cell subset (85% of PB T cells) while the antigen defined by the monoclonal antibody 4F2 is present on a subset (70%) of activated PB T cells and on circulating PB monocytes. In contrast to normal subjects in whom 60-70% of circulating PB mononuclear cells were 3A1(+) T cells, PB mononuclear cells from six CTCL patients studied had an average of only 10.6+/-3.2% 3A1(+) T cells. Whereas 85% of E-rosette positive cells from normal individuals were 3A1(+), virtually all E-rosette positive T cells from the Sezary patients were 3A1(-). Two patients with high numbers of circulating Sezary T cells had both aneuploid and diploid PB T cell populations present; after separation of PB T cells into 3A1(+) and 3A1(-) cell suspensions, all 3A1(-) cells were found to be aneuploid. In contrast to normal resting PB T cells which were 4F2(-), all PB Sezary cells were 4F2(+), suggesting a state of activation. The 3A1 antigen was on a variety of acute lymphoblastic leukemia T cell lines (HSB-2, RPMI-8402, MOLT4, CEM) but was absent on the Hut 78 and Hut 102 Sezary T cell lines. Using rabbit anti-human T and anti-human Ia (p23, 30) antisera, we found that all malignant Sezary PB cells tested were killed by anti-T cell antiserum plus complement but not by anti-Ia plus complement. In contrast, Sezary cell lines Hut 78 and 102, were killed by both anti-T cell antiserum and anti-Ia plus complement. Similar to 3A1(-) normal PB T cells, 3A1(-) Sezary PB T cells proliferated poorly to phytohemagglutinin and concanavalin A. However, 3A1(-) Sezary T cells were able to provide T cell help towards pokeweed mitogen-induced in vitro B cell immunoglobulin synthesis, an immunoregulatory function limited to 3A1(+) T cells in normal subjects.Thus, the 3A1 antigen is present on 85% of normal PB T cells, and on most T-acute lymphoblastic leukemia lines tested; in contrast the 3A1 antigen is not present on the majority of circulating malignant Sezary PB T cells nor on T cell lines derived from malignant Sezary T cells. The lack of expression of the 3A1 antigen may be associated with malignant transformation of T cells in CTCL and may be an important marker for tracing the clonal origin of the malignant Sezary T cell.

Adult↗
PubMed1980

Properties of monoclonal antibodies specific for determinants of a protein antigen, myoglobin.

Monoclonal hybridoma antibodies specific for the protein antigen sperm whale myoglobin were produced using hyperimmune spleen cells from mice with the genetic trait of high responsiveness to myoglobin. Antibodies from the several clones tested were found to produce linear Scatchard plots, as predicted for homogeneous antibodies, and to possess high affinities for the immunogen (KA congruent to 10(9) M-1). None of the monoclonal antibodies tested reacted with either fragment (1-55) or fragment (132-153) of sperm whale myoglobin. Competitive binding assays using human and horse myoglobins suggested that several of these monoclonal antibodies, which can readily distinguish these myoglobins, recognize different antigenic determinants on the myoglobin molecule. Studies using additional myoglobin sequence variants as competitors should be able to more closely define these antigenic determinants.

Animals↗
PubMed1979

Adenylate cyclase and acetylcholine release regulated by separate serotonin receptors of somatic cell hybrids.

Serotonin activates adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] of NCB-20 neuroblastoma--brain hybrid cells with an activation constant of 530 nM, but has little or no effect on cellular cyclic AMP or cyclic GMP content of NIE-115 neuroblastoma or NG108-15 hybrid cells. In homogenates of NCB-20 hybrid cells, lysergic acid diethylamide stimulates adenylate cyclase activity (Kact = 12 nM) and partially inhibits (Ki = 10 nM) the stimulation of adenylate cyclase activity by serotonin. No desensitization was detected of serotonin receptors coupled to adenylate cyclase. Serotonin also depolarizes NCB-20, NG108-15, and NIE-115 cells and increases acetylcholine release. Serotonin receptors mediating depolarizing responses desensitize rapidly and reversibly, and the depolarizing effects of serotonin are neither mimicked nor inhibited by lysergic acid diethylamide. These results indicate that (i) NCB-20 cells possess at least two species of serotonin receptors, which independently regulate cellular functions, (ii) activation of adenylate cyclase does not directly affect membrane potential or acetylcholine release, and (iii) serotonin-dependent cell depolarization does not affect cyclic AMP or cyclic GMP synthesis in the cell lines tested.

Acetylcholine↗
PubMed1976

Extinction of globin gene expression in human fibroblast x mouse erythroleukemia cell hybrids.

We have chosen human fibroblast x mouse erythroleukemia hybrid cells as a model system to examine regulation of unique genes. The globin genes were studied as a marker of erythroid differentiation. Three separate hybrid cell lines were incubated in 2% dimethylsulfoxide, an agent which induces erythroid differentiation of the parental erythroleukemia cells. Neither human nor mouse globin mRNA sequences could be detected by a sensitive molecular hybridization assay which utilized globin complementary D N A. However, td n a from one of the cell lines was shown to contain both the mouse and humand globin genes. Thus, loss of the genes by chromosomal segregation did not account for their failure to be expressed. Cocultivation of the mouse erythroleukemia cells with excess human fibroblasts did not prevent erythroid differentiation of the erythroleukemia cells in the presence of dimethylsulfoxide. Similarly globin gene expression was preserved in tetraploid cells generated by fusion of two erythroleukemia lines. Thus, extinction of globin geneated by fusion of two erythroleukemia lines. Thus, extinction of blobin gene expression in the human fibroblast x erythroleukemia hybrids occurred at the level of mRNA production and appeared to be due to the presence of the fibroblast genome within the hybrial cell.

Animals↗
PubMed1975

Neuronal properties of hybrid neuroblastoma X sympathetic ganglion cells.

Clonal mouse neuroblastoma cells without tyrosine 3-monooxygenase [EC 1.14.16.2; tyrosine hydroxylase; L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating)] activity were fused with normal cells from embryonic mouse sympathetic ganglia. One of the 37 hybrid cell lines obtained possesses high tyrosine 3-monooxygenase activity and synthesizes dopamine. These cells also have excitable membranes and generate action potentials in response to electrical stimuli. Thus hybrid cells, generated by fusion of neuroblastoma cells with normal cells from the nervous system, can acquire neural properties not found with the parental neuroblastoma cells.

Action Potentials↗
PubMed1975

Hemoglobin synthesis in somatic cell hybrids: globin gene expression in hybrids between mouse erythroleukemia and human marrow cells or fibroblasts.

Somatic cell hybrids were generated by fusion of mouse erythroleukemia cells either to mouse L cells (B82), human fibroblasts (W1-18 VA2), or human marrow fractions enriched in erythroblasts. The hybrid cells were examined for globin gene expression by benzidine staining to detect cytoplasmic hemoglobin, and by molecular hybridization of cellular RNA to globin complementary DNA (cDNA) to detect globin messenger RNA (MRNA). The fibroblast (human or mouse) times erythroleukemia cell hybrids grown in monolayer retained most of the chromosomes of each parent. Neither cytoplasmic hemoglobin nor globin mRNA was detected in dimethylsulfoxide-treated fibroblast times erythroleukemia hybrid cells, indicating extinction of hemoglobin synthesis prior to the formation of cytoplasmic mRNA. The human marrow times mouse erythroleukemia hybrid cells grown in suspension culture contained only a few human chromosomes and exhibited low levels of hemoglobin synthesis which were amplified by 2% dimethylsulfoxide. Mouse (but not human) globin mRNA was demonstrated in these hybrid cells. The results suggest that somatic cell hybrids may be useful in searching for genetic factors which regulate activity of the globin genes.

Bone Marrow Cells↗
PubMed1975

Biological properties of a type C virus isolated from a human X mouse hybrid cell line.

The biological properties of the HMV-1 virus, spontaneously released from a human X C57BL/6 mouse hybrid cell line, were similar to those of RadLV, the prototype B-tropic virus of C57BL/6 mice. Both viruses replicated on B-type mouse cells and in the wild mouse cell line SC-1. The plaque-forming abilities of the two viruses were relatively low, but gradually increased after passage in new host cells. Both viruses were neutralized by AKR antisera but not by FMR antisera. HMV-1 virus could rescue the defective sarcoma genome from S+H- mouse cells. The pseudotype sarcoma virus so produced was deficient in "helper virus" activity. Newborn mice inoculated with HMV-1 virus remained tumor-free over a 1-yr observation period.

AKR murine leukemia virus↗
PubMed1972

An active electrical response in fibroblasts.

L cells have a resting potential of about -16 mv (internal negative) at 37 degrees C in Dulbecco's modified Eagle's medium containing 10% fetal calf serum and a potassium concentration of 5.4 mM. Membrane resistivity is about 20,000 ohmcm(2) when the surface filopodia described by others are taken into account. Mechanical and electrical stimuli can evoke an active response from mouse L cells, cells of the 3T3 line, and normal fibroblasts which we have termed hyperpolarizing activation or the H.A. response. This consists of a prolonged (3-5 sec) increase in the membrane permeability by a factor of 2-10 with a parallel increase in membrane potential to about -50 mv. The reversal potential for the H.A. response is -80 mv. The resting cells are depolarized to about -12 mv when the external medium contains 27 mM potassium, and the potential reached at the peak of the H.A. response is about -30 mv. The reversal potential for the H.A. response is about -40 mv in 27 mM external potassium. This effect of potassium ions on the reversal potential of the H.A. response leads us to conclude that the response represents an increase in membrane permeability, predominantly to potassium, by at least a factor of five. This increase must be greater than 20-fold if previous measurements of the ratio of potassium permeability to chloride permeability in L cells are valid for the preparation used in the present study.

Animals↗
PubMed1971

Genes for neuronal properties expressed in neuroblastoma x L cell hybrids.

Neuroblastoma cells with electrically excitable membranes were fused with electrically passive L cells having a hitherto undescribed electrical marker. Hybrid cells, examined 10-40 generations after fusion, were found to be electrically excitable. The results show that at least a part of the genetic information for neuron differentiation can be functionally expressed in N x L hybrid cells. Evidence for the regulation of action potential components was also found.

Action Potentials↗