Interferon antibodies in patients with infectious diseases

Interferons (IFNs) are generally recognized as the most important therapeutic agent in some infectious diseases such as chronic hepatitis B and C. Since the early clinical trials it was documented that the therapeutic use of IFNs could be complicated by the development of antibodies able to neutralize or to bind to the IFN molecule. After several years of research it is now widely accepted that the presence of circulating anti-IFN antibodies may affect the response to IFN. Here we summarize what is currently know on the clinical significance of antibodies to IFN in IFN-treated viral diseases patients.     

Isolation of an evolutionarily conserved epidermal growth factor receptor cDNA from human A431 carcinoma cells

Complementary DNA corresponding to total poly(A)+-RNA from the human A431 epidermoid carcinoma cell line was cloned in the phage expression vector lambda gt 11. An epidermal growth factor (EGF) receptor cDNA clone was obtained by screening of the expression library with a rabbit polyclonal antibody (IgG), raised to the purified A431 EGF receptor, in combination with [125I]protein A of S. aureus. The cloned cDNA was able to select, by hybridization, messenger RNA which was translated in Xenopus oocytes and yielded an immunoprecipitable EGF receptor protein of Mr = 160,000. The insert of this cDNA (phEGFR-1), is approximately 880 base pairs in length and encodes the carboxyterminal portion of the EGF receptor protein. Its sequence is evolutionarily conserved among vertebrates as shown by hybridization to unique chromosomal DNA sequences from human, baboon, dog, rat, mouse and frog.     

Determination of the minimal inhibitory concentration of Amphotericin B and Miconazole for 21 strains of Aspergillus

The susceptibility of 21 strains ofAspergillus (11 ofA. fumigatus, 8 ofA. niger, and 2 ofA. flavus) isolated from human pathologic specimens to Amphotericin B and Miconazole has been comparatively studied. Determination of the minimal inhibitory concentration of both drugs in a liquid medium showed a noticeably variability for the different strains. The values obtained for Amphotericin B varied between 0.25g/ml (2 strains) and 1.25g/ml (5 strains) after 48 hours, and between 1.25g/ml (1 strain) and 50g/ml (1 strain) after 10 days. For Miconazole the results varied between 0.1g/ml (1 strain) and 25g/ml (1 strain) after 48 hours of incubation, and between 0.5g/ml (5 strains) and > 100g/ml after 10 days. The variability of these results indicates the usefulness of carrying ourin vitro sensitivity studies whenever it is possible.     

Stimulation of the adenylate cyclase of A B16 melanoma cell line by pro-opiocortin-related peptides--a structure-activity study

The ability of alpha-melanotrophin (alpha-MSH or ACTH 1-acetyl-13 amide) and other structurally related peptides derived from the common precursor, pro-opiocortin, to stimulate adenylate cyclase activity in a pigmented B16 mouse melanoma was investigated. The peptides ACTH 1-39, ACTH 1-24, alpha-MSH, ACTH 1-13 amide and beta-MSH all stimulated the enzyme to a similar maximal extent and with similar potency (ED50 = 1.3 . 10(-6) M) except that ACTH 1-39 was slightly less potent (ED50 = 5 . 10(-6) M). ACTH 4-10 (ED50 = 4 . 10(-5) M) and gamma-MSH (ED50 = 5 . 10(-6) M) were partial agonists. ACTH 1-10 was no more effective than ACTH 4-10 in stimulating the enzyme whereas ACTH 1-13 amide was a full agonist. The peptides beta-endorphin and its derivatives, Met-enkephalin and melanotrophin potentiating factor (MPF), failed to stimulate the enzyme. We suggest that the B16 melanoma requires not only the sequence ACTH 4-10 but also some part of the sequence ACTH 11-13, or a similar sequence in the terminal portion of beta-MSH, for full activation of the receptor-linked enzyme.     

Effects of amphotericin B on the electrical properties ofNecturus gallbladder: Intracellular microelectrode studies

Summary Intracellular microelectrode techniques were employed to study the mechanism by which amphotericin B induces a transient mucosa-negative transepithelial potential (V _ms) in the gallbladder ofNecturus. When the tissue was incubated in standard Na-Ringer's solution, the antibiotic reduced the apical membrane potential by about 40 mV, and the basolateral membrane potential by about 35 mV whereas the transepithelial potential increased by about 5 mV. The electrical resistance of the apical membrane fell by 83%, and that of the basolateral membrane by 40%; the paracellular resistance remained unchanged. Circuit analysis indicated that the equivalent electromotive forces of the apical and basolateral membranes fell by 35 and 11 mV, respectively. Changes in potentials and resistances produced by ionic substitutions in the mucosal bathing medium showed that amphotericin B produces a nonselective increase in apical membrane small monovalent cation conductance (K, Na, Li). In the presence of Na-Ringer's on the mucosal side, this resulted in a reduction of the K permselectivity of the membrane, and thus in a fall of its equivalent emf. During short term exposure to amphotericin B,P _Na/P _Cl across the paracellular pathway did not change significantly, whereasP _K/P _Na doubled. These results indicate that V _ms is due to an increase of g_Na across the luminal membranes of the epithelial cells (Cremaschiet al., 1977,J. Membrane Biol. 34:55); the data do not support the alternative hypothesis (Rose & Nahrwold, 1976.J. Membrane Biol. 29:1) that V _ms results from a reduction in shuntP _Na/P _Cl acting in combination with a rheogenic basolateral Na pump.     

Alteration of mitochondrial genomes containing atpA genes in the sexual progeny of cybrids between Raphanus sativus cms line and Brassica napus cv. Westar

Summary We have investigated the fate of the mitochondrial genomes of cybrids derived from donor-recipient protoplast fusion between X-irradiated Raphanus sativus (cms line) and iodoacetamide-treated Brassica napus cv. Westar. Two out of ten fusion products were male-sterile with the diploid chromosome number of B. napus. The mitochondrial (mt) genomes of the cybrids and their progeny were further analyzed by DNA-DNA hybridizaion using the pea mitochondrial ATPase subunit gene (atpA) as a probe. One cybrid, 18-3, had a 3.0 kb fragment characteristic of B. napus and a 2.0 kb non-parental fragment when the BamHI-digested DNA was hybridized with the probe. In the first-backcrossed progeny of this cybrid, the hybridization pattern was not stably inherited. A 4.0 kb radish fragment, not detectable in the cybrid, appeared in one of the BC₁ generation siblings, and the 2.0 kb non-parental fragment was lost in another. The hybridization patterns in BC₁ progeny siblings of cybrid 12-9 were also varied. The alteration of mtDNA in the cybrid progeny continued to the BC₂ generation. There was no clear evidence of a heteroplasmic state or of sub-stoichiometric molecules in the mt genome of cybrid 18-3. A possible cause of the observed alteration in the mt genome is discussed.