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Biomedical subjects

L Eiden

Publications and source records attributed to L Eiden.

12 recordsLinked to original sources
PubMed1996

In vitro effects of anti-HIV immunotoxins directed against multiple epitopes on HIV type 1 envelope glycoprotein 160.

We have used a panel of anti-gp160 MAbs to construct anti-HIV immunotoxins by coupling antibodies to ricin A chain (RAC). The ability of the immunotoxins to kill HIV-1-infected cells and halt the spread of infection was tested in tissue culture on persistently and acutely infected cell lines and primary lymphocyte cultures stimulated with phytohemagglutinin (PHA blasts). Laboratory strains and clinical isolates of HIV both were tested. The constitution and antigen-binding capacity of the immunotoxins were confirmed by ELISA and indirect immunofluorescence. Immunotoxins that bind epitopes exposed on the cell surface effectively killed persistently infected cells, although killing was not directly proportional to binding of immunotoxin to cell. The activity of anti-gp41, but not anti-gp120, immunotoxins was markedly enhanced in the presence of soluble CD4 or peptides corresponding to the CDR3 region of CD4. CD4-mediated enhancement of anti-gp41 immunotoxin activity was observed for laboratory strains neutralized by sCD4 and for clinical isolates that were resistant to neutralization by sCD4. Immunotoxin action was potentiated by brefeldin A, bafilomycin A1, cortisone, and an amphipathic fusion peptide, but not by cytochalasin D, nocodazol, monodansyl cadaverine, or trans-retinoic acid. Anti-HIV immunotoxins are useful tool with which to study the functional expression of gp120/gp41 antigens on the surface of HIV-infected cells, as well as potential AIDS therapeutics. Because these studies relate to the accessibility of viral antigens to antibody-mediated attack, these studies also have relevance for vaccine development.

Anti-Bacterial Agents↗
PubMed1996

Neuropeptide genes: targets of activity-dependent signal transduction.

Neuroendocrine cells respond to hormones and synaptic input by increasing or decreasing their own electrical activity and secretory output, and by changes in the repertoire of expression of neuronal genes. Neuropeptide genes are among those whose transcription rates can be dramatically up-and downregulated when neuronal activity is altered. In the last decade or so, our understanding of neuropeptide gene regulation has evolved from the concept of calcium-dependent coupling of neuropeptide secretion and biosynthesis to the current perspective of neuropeptide genes as the targets of multiple intracellular signaling pathways, entrained by intrinsic electrical activity and by transsynaptic influences. This review describes our current understanding of neuropeptide gene regulation in the adrenal gland as well as in the peripheral and central nervous systems. Particular emphasis is placed on the molecular mechanisms that allow unique patterns of expression of neuropeptide genes within specific types of neuroendocrine cells that contribute to the remarkable anatomical specificity of neuropeptide gene expression.

Adrenal Medulla↗
PubMed1993

Cortical astrocytosis in juvenile rhesus monkeys infected with simian immunodeficiency virus.

The pattern of expression of GFAP immunoreactivity in astrocytes of the juvenile rhesus monkey cortex was examined following infection with simian immunodeficiency virus (SIV). Blocks of cerebral cortex plus subjacent white matter from saline- and formalin-perfused brain were examined by peroxidase-linked immunochemical and immunofluorescence staining of deparaffinized sections. Strong GFAP immunoreactivity was found in astrocytic cells in both uninfected and SIV-infected juvenile macaque in the subpial cerebral cortex and in subcortical white matter, where GFAP-positive cells were abundant. GFAP staining of cortical layers 2-6 on the other hand was weak or absent in three uninfected controls and one infected animal without cognitive impairment, but moderate to strong in animals productively infected with SIV that demonstrated cognitive and/or motor impairment. These data demonstrate a cortical locus of astrocytic activation in rhesus monkeys infected with primate immunodeficiency virus isolate SIVB670 which, like HIV-1 in man, causes motor/cognitive impairment as well as immunodeficiency disease.

Animals↗
PubMed1988

Phylogenetic distribution of peptides related to chromogranins A and B.

The presence of chromogranin-related peptides in a wide range of species was investigated by one and two-dimensional electrophoresis followed by immunoblotting. Antisera against bovine chromogranins A and B and the peptide WE-14 (chromogranin A316-329) were used. Chromogranins were identified by their heat stability, by their electrophoretic behavior, and by immunological cross-reaction with antisera. In all species investigated ranging from mammals to birds, amphibians, fish, and arthropods, chromogranin A- and B-like proteins could be demonstrated. For all species, there was an immunological cross-reaction with antisera against bovine chromogranins. The molecular sizes and isoelectric points of the chromogranins were similar in all species. The antiserum against WE-14 cross-reacted with pig, rat, and chicken chromogranins. It is concluded that the chromogranins A and B have a widespread phylogenetic distribution with a significant conservation of molecular size, isoelectric points, and immunological epitopes. This is consistent with the concept that these peptides have a specific function.

Animals↗
PubMed1983

Characterization of a teleost gonadotropin-releasing hormone.

A peptide that is recognized by certain antibodies raised against mammalian gonadotropin-releasing hormone has been purified from extracts of salmon brains by gel filtration and high-performance liquid chromatography. The primary structure of this 10-residue peptide is less than Glu-His-Trp-Ser-Tyr-Gly-Trp-Leu-Pro-Gly-NH2. This represents a difference of two amino acids between salmon and mammalian gonadotropin-releasing hormone and demonstrates that most of the molecule has been conserved during evolution. The synthetic form of salmon gonadotropin-releasing hormone is less potent than is mammalian gonadotropin-releasing hormone on mammalian cells and is biologically active in salmon.

Amino Acid Sequence↗
PubMed1982

[Opiate peptides of the adrenal medulla (author's transl)].

Significant concentrations of enkephalins are present in the adrenal medulla, notably in man, ox and dog. High molecular weight peptides precursors of enkephalin pentapeptide can also be demonstrated in the same tissue. Although the biosynthesis of enkephalins has not yet been completely elucidated, it seems to follow a pathway different from that of beta-endorphin. The secretion of enkephalins is regulated by the same mechanisms as the secretion of catecholamines. Enkephalins act locally by modulating catecholamine release, but since they are released into the systemic circulation, another, still ill-defined hormonal action is possible.

Adrenal Medulla↗
PubMed1982

Primary structure of the human Met- and Leu-enkephalin precursor and its mRNA.

The nucleotide sequence of a complete cDNA copy of enkephalin precursor mRNA from human phaeochromocytoma is reported. The corresponding amino acid sequence shows that the precursor is 267 amino acids long and contains six interspersed Met-enkephalin sequences and one Leu-enkephalin sequence. Five of the seven enkephalins are flanked on both sides by pairs of basic amino acid residues. The precursors does not contain the sequences of the opioid peptides, dynorphin, alpha-neo-endorphin or beta-endorphin.

Amino Acid Sequence↗
PubMed1982

Studies on the presence of angiotensin II in rat brain.

Angiotensin II-like immunoreactivity was extracted from brains of bilaterally nephrectomized rats with several different extraction procedures (90% methanol, distilled water, 6 M urea, 0.1 N HCl, and 2 M acetic acid). The activity was measured with radioimmunoassays using three different antisera, two of which had been used previously for immunocytochemical studies. With none of the extraction procedures or antisera employed was more than 80 pg/g wet weight of angiotensin II-like immunoreactivity found. Analysis was undertaken with two different reverse-phase high-pressure liquid chromatography systems; in one of these the immunoreactivity did not coelute with angiotensin II or III. On the basis of its elution pattern from a molecular sieving column, the immunoreactivity seems to have a higher molecular weight than angiotensin II. It is concluded that neurons in the brain do not synthesize and store angiotensin II.

Angiotensin II↗
PubMed1982

[Demonstration of enkephalins in pheochromocytoma].

Adrenal medulla has recently been shown to contain high concentrations of enkephalin immunoreactive peptides. In the present study, we report the levels of M-ENK and L-ENK in extracts from 6 cases of human pheochromocytoma. The molecular forms of M-ENK have been characterized by gel filtration chromatography and HPLC. mRNA extracted from one tumor has been proved to code for a 80,000 kilo daltons protein containing M-ENK sequence. M-ENK immunoreactive peptides are secreted in the culture medium of dispersed cultured cells of human pheochromocytoma. This secretion is stimulated when nicotine (10(5) M) is added to the medium. However, the level of plasma M-ENK in pheochromocytoma patients is not significantly different from normal patients. Data from Holaday and al. have established that naloxone (an opiate antagonist) has a beneficial role in shock. But the origin and meaning of plasma M-ENK remain to be established.

Adrenal Gland Neoplasms↗