摘要:

Biotechnological processes are having a major impact on many industrial sectors, including the pharmaceutical industry. The contributions of recombinant DNA and hybridoma technologies to modern therapeutics include production of natural and unnatural peptides, subunit vaccines, monoclonal antibodies and nucleic acid hybridization probes for in vitro and in vivo diagnostics and biological imaging, therapeutic monoclonal antibodies as tissue‐specific delivery systems or as agents to confer passive immunity, production of therapeutic targets for rational drug design, and the use of cloned enzymes as stereospecific catalysts in large‐scale production of small medicinal molecules. Biotechnological advances have led to the identification of a discrete set of genes, oncogenes, which may be essential contributing factors for a great variety and number of human cancers. In addition, biotechnological innovations are fostering the exploitation of oncogenes as novel therapeutic targets for cancer diagnosis, prognosis, and treatment. Because oncogenes are activated in transformation by either qualitative or quantitative mechanisms, however, different biotechnology‐based therapeutic approaches are required for each class.— Huber, B. E. Therapeutic opportunities involving cellular oncogenes: novel approaches fostered by biotechnology.FASEB J.3: 5‐13; 1989.

ISSN:0892-6638    

DOI:10.1096/fasebj.3.1.2642869

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

The primary sequence of human DNA polymerase α deduced from the full‐length cDNA contains regions of striking similarity to sequences in replicative DNA polymerases fromEscherichia coliphages PRD1 and T4,Bacillusphage ɸ19, yeast DNA polymerase I, yeast linear plasmid pGKL1, maize S1 mitochondrial DNA, herpes family viruses, vaccinia virus, and adenovirus. The conservation of these homologous regions across this vast phylogenetic expanse indicates that these prokaryotic and eukaryotic DNA polymerases may all have evolved from a common primordial gene. Based on the sequence analysis and genetic results from yeast and herpes simplex virus studies, these consensus sequences are suggested to define potential sites that subserve essential roles in the DNA polymerase reaction. Two of these conserved regions appear to participate directly in the active site required for substrate deoxynucleotide interaction. One region toward the carboxyl‐terminus has the potential to be the DNA interacting domain, whereas a potential DNA primase interaction domain is predicted toward the amino‐terminus. The provisional assignment of these domains can be used to identify unique or dissimilar features of functionally homologous catalytic sites in viral DNA polymerases of pathogenetic significance and thereby serve to guide more rational antiviral drug design.— Wang, T. S.‐E.; Wong, S. W.; Korn, D. Human DNA polymerase α: predicted functional domains and relationships with viral DNA polymerases.FASEB J.3: 14‐21; 1989.

ISSN:0892-6638    

DOI:10.1096/fasebj.3.1.2642867

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

Acquired immune deficiency syndrome (AIDS) is a disease caused by the human immunodeficiency virus (HIV) in which cellular immune functions are severely impaired. Acute infection and subsequent destruction of helper T cells, although occurring readily in cell cultures, do not appear to be the only mechanisms mediating helper T cell loss. Other mechanisms that may account for the loss of helper T cells include: T cell syncytia formation, decreased T cell production, and autoimmune‐related destruction of helper T cells. Immune abnormalities seen early in the course of HIV infection include immune hyperactivation and autoimmune phenomena suggestive of immune dysregulation rather than immune deficiency. Many changes in immune function are, in fact, seen in HIV‐seropositive patients who possess a normal number of helper T cells. Mechanisms (other than the loss of helper T cells) that may contribute to the immune abnormalities seen in these patients include noninfectious effects of HIV and HIV proteins, effects of HIV on non‐T cells, autoimmune‐related manifestations of HIV infection, and HIV‐induced activation of normal immunosuppressive circuits.— Edelman, A. S.; Zolla‐Pazner, S. AIDS: a syndrome of immune dysregulation, dysfunction, and deficiency.FASEB J.3: 22‐30; 1989.

ISSN:0892-6638    

DOI:10.1096/fasebj.3.1.2562947

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

Vascular smooth muscle relaxation in response to chemically diverse naturally occurring neurotransmitters and autacoids has been attributed to the formation and/or release of one or more vascular endothelium‐derived relaxing factors (EDRFs) distinct from prostacyclin. The chemical, biochemical, and pharmacological properties of one such EDRF resemble closely the properties of nitric oxide (NO). Thus, both arterial and venous EDRFs as well as authentic NO cause heme‐dependent activation of soluble guanylate cyclase, endothelium‐independent vascular and nonvascular smooth muscle relaxation accompanied by tissue cyclic GMP formation, and inhibition of platelet aggregation and adhesion to endothelial cell surfaces. EDRF from artery, vein, and freshly harvested and cultured aortic endothelial cells was recently identified as NO or a labile nitroso species as assessed by chemical assay and bioassay. Endothelium‐derived NO (EDNO) has an ultrashort half‐life of 3‐5 s due to spontaneous oxidation to nitrite and nitrate, both of which have only weak biological activity. EDNO can be synthesized from L‐arginine and possibly other basic amino acids and polypeptides, perhaps by oxidative metabolic pathways that could involve polyunsaturated fatty acid‐derived oxygen radicals. Inorganic nitrite could serve as both a stored precursor and an inactivation product of EDNO. EDNO and related EDRFs may serve physiological and/or pathophysiological roles in the regulation of local blood flow and platelet function.— Ignarro, L. J. Endothelium‐derived nitric oxide: actions and properties.FASEB J.3: 31‐36; 1989.

ISSN:0892-6638    

DOI:10.1096/fasebj.3.1.2642868

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

Normal murine B lymphocytes are not known to be effectors of the Fc receptor‐mediated, antibody‐dependent cellular cytotoxicity (ADCC). In contrast, we report here that highly purified splenic B cells from mammary tumor‐bearing mice develop the potential of lysing antibody‐coated target cells. These lymphocytes are characterized by being G‐10 nonadherent, nylon wool adherent, sIg∗, FcR+, Thy 1.2−, asialo GM1−, and the immunoglobulin heavy‐chain genes of both chromosomes are rearranged. The lytic reaction is characterized by a noninterdigitating binding and by the appearance of endocytotic vesicles in the target cells. Nuclear disintegration occurs 18 h after initial effector‐target cell conjugate formation. At such time, only minor cytoplasmic membrane alterations are evident. The emergence of killer B cells in tumor‐bearing hosts indicates that all lymphoreticular cell types bearing Fc receptors are capable of mediating ADCC.— Lopez, D. M.; Blomberg, B. B.; Padmanabhan, R. R.; Bourguignon, L. Y. W. Nuclear disintegration of target cells by killer B lymphocytes from tumor‐bearing mice.FASEB J.3: 37‐43; 1989.

ISSN:0892-6638    

DOI:10.1096/fasebj.3.1.2783411

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

In this paper we examine the effect of the vasodilator peptide bradykinin on endothelial cell regulation of phosphoinositide (PI) turnover. The data show that the activation of PI turnover by bradykinin in bovine pulmonary artery endothelial cells is insensitive to pertussis toxin, which ADP ribosylates a membrane protein of mol wt 40,000. However, this effect of bradykinin can be potentiated by guanosine 5‘‐O‐(3‐thio)triphosphate (GTPγS), an activator of G proteins, and depressed by guanosine 5‘‐O‐(2‐thio)diphosphate (GDPβS), an inhibitor of G proteins. After endothelial cells were pre‐incubated for 1 h with GTPγS, there was a three‐ to fourfold increase in PI turnover. Preincubation of cells with GDPβS did not affect the basal level of PI turnover, but completely prevented activation of PI turnover by bradykinin. 4β‐Phorbol‐12β‐myristate‐13α‐acetate can block the bradykinin‐stimulated inositol monophosphate formation in cultured endothelial cells. The effects of bradykinin on PI turnover were blocked by B2antagonists but not by B1antagonists. Taken together, these results indicate that in endothelial cells the bradykinin B2receptor is coupled to phospholipase C via a G protein (or proteins) that is not a substrate for pertussis toxin (neither Ginor Go).— Voyno‐Yasenetskaya, T. A.; Tkachuk, V. A.; Cheknyova, E. G.; Panchenko, M. P.; Grigorian, G. Y.; Vavrek, R. J.; Stewart, J. M.; Ryan, U. S. Guanine nucleotide‐dependent, pertussis toxin‐insensitive regulation of phosphoinositide turnover by bradykinin in bovine pulmonary artery endothelial cells.FASEB J.3: 44‐51; 1989.

ISSN:0892-6638    

DOI:10.1096/fasebj.3.1.2535990

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

Heterogeneity of cytosolic pH was studied with compounds that distribute between the cytosol and mitochondrial matrix in fundamentally different ways, i.e., according to the extent of ionization or according to the function of H+‐coupled transport systems. Results show that the average cytosolic pH is considerably more alkaline than the region to which mitochondria are exposed. Because mitochondria are localized predominantly in the basal region, the results are consistent with a transcellular pH gradient within the cytosol of proximal tubule cells. Experiments analyzing the effects of inhibiting efflux of HCO3−at the basal surface and Na+‐H+exchange at the apical surface support the interpretation that the function of these systems contributes to the transcellular pH gradient. The existence of a heterogeneity in pH within the cytosol has important implications concerning the function and regulation of numerous cell processes.—Aw, T. Y.; Jones, D. P. Heterogeneity of pH in the aqueous cytoplasm of renal proximal tubule cells.FASEB J.3: 52‐58; 1989.

ISSN:0892-6638    

DOI:10.1096/fasebj.3.1.2910737

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

Exposure of cultured hepatoma 1c1c7 cells to KCN and iodoacetate, to produce chemical anoxia, caused a rapid and sustained increase in cytosolic‐free Ca2+concentration, which was associated with depletion of intracellular ATP and glutathione. These changes occurred before the loss of cell viability and were accompanied by the appearance of plasma membrane blebs. Pretreatment of the cells with the Ca2+chelators Quin 2 or BAPTA markedly delayed both the onset of blebbing and loss of cell viability, but did not affect KCN‐ and iodoacetate‐induced loss of ATP and glutathione. Together, these results strongly suggest that a sustained increase in cytosolic Ca2+concentration plays an important role in killing of hepatoma cells by chemical anoxia.— Nicotera, P.; Thor, H.; Orrenius, S. Cytosolic‐free Ca2+and cell killing in hepatoma 1c1c7 cells exposed to chemical anoxia.FASEB J.3: 59‐64; 1989.

ISSN:0892-6638    

DOI:10.1096/fasebj.3.1.2910738

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

We detected platelet‐activating substance in gastrointestinal areas, which was confirmed to be platelet‐activating factor (PAF) on the basis of the following findings:1) it comigrated with authentic PAF on thin‐layer chromatography;2) it did not aggregate PAF‐desensitized platelets; and3) its activity was completely antagonized by the receptor antagonists CV3988 and L‐652,731. The level of PAF was determined with a bioassay method based on the release of [3H] serotonin from washed rabbit platelets. In the normal rat stomach, the level of PAF was high in the antrum (940 ± 200 nmol PAF/mol phosphorus of original phospholipids), especially in the antral mucosa (1801 ± 426 nmol/mol phosphorus of original phospholipids). The stomach PAF level was significantly altered by water immersion stress. Stress for a period of 1 h was associated with a decrease in the antral PAF level to 39 ± 7% of that of untreated controls. This low PAF level persisted during stress. On the other hand, in the corpus, stress for periods of 1 and 3 h was associated with decreases in the PAF content, and further stress (7 h) resulted in restoration of the PAF level to normal. Furthermore, 7 h of stress was associated with distinct hemorrhagic lesions, which were prevented by CV3988 infused i.v. before the stress. This is the first report of an association between a decrease of the endogenous PAF level in animal tissues and tissue damage.—Sugatani, J.; Fujimura, K.; Miwa, M.; Mizuno, T.; Sameshima, Y.; Saito, K. Occurrence of platelet‐activating factor (PAF) in normal rat stomach and alteration of PAF level by water immersion stress.FASEB J.3: 65‐70; 1989.

ISSN:0892-6638    

DOI:10.1096/fasebj.3.1.2910739

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

The binding of epidermal growth factor (EGF) to its plasma membrane receptor results in the stimulation of a tyrosyl residue‐specific protein kinase, which has been shown to be part of the receptor. The mechanism by which EGF binding gives rise to the stimulation of kinase activity is not understood in detail; however, a number of recent studies have implicated receptor dimerization or oligomerization in this process. We prepared Triton X‐100 extracts of A431 cells in which the concentration of EGF receptors was on the order of 10−7M. When samples of the extracts were incubated with or without EGF and then treated with the high‐yield cross‐linking reagent bis(sulfosuccinimidyl)suberate (BS3), covalent receptor dimers could be detected in high yield in samples that had been treated with both EGF and BS3, whereas only monomeric receptor was detected in untreated samples or in samples that had been treated with either EGF or BS3. The yield of receptor dimers trapped by cross‐linking correlated with the stimulation of autophosphorylation by EGF and with the concentration of EGF present. EGF‐induced receptor dimers were also efficiently cross‐linked in highly purified receptor preparations, suggesting that EGF‐induced dimerization is a process intrinsic to the receptor, requiring no additional accessory proteins.— Fanger, B. O.; Stephens, J. E.; Staros, J. V. High‐yield trapping of EGF‐induced receptor dimers by chemical cross‐linking.FASEB J.3: 71‐75; 1989.

ISSN:0892-6638    

DOI:10.1096/fasebj.3.1.2783412

出版商:Wiley    

年代:1989

数据来源: WILEY