Genetic engineering of human interferons from lymphoblastoid cells: II. Construction of trp expression plasmids and their use for efficient expression of IFN-alpha J1.
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Burkitt Lymphoma↗
Biomedical subjects
S Cohen
Publications and source records attributed to S Cohen.
Genetic engineering of human interferons from lymphoblastoid cells: III. Purification, physicochemical and biological properties of bacterial IFN-alpha J1.
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Antibodies↗
Pit and fissure sealants as a caries preventive measure.
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Dental Bonding↗
Interferon-gamma modulates HLA class II antigen expression on cultured human thymic epithelial cells.
Cultures of human thymic epithelial cells (TEC) were tested for the expression of HLA class I (A, B, C) and class II (DR and DC) antigens by indirect immunofluorescence. The epithelial nature of the cells was proven by using an antikeratin antiserum. A high level of expression (close to 100% positive cells) of HLA class I antigens was observed on TEC at the beginning of the culture and remained unchanged for up to 12 days. In contrast, HLA class II antigen expression (85% DR+ and 75% DC+ cells on day 2) decreased gradually and reached very low levels (less than 5% DR+ or DC+) by day 7 of culture. This loss of class II antigen expression was not seen when cultures were performed in the presence of supernatants from activated T cells containing interferon-gamma (IFN-gamma). Furthermore, the presence of recombinant IFN-gamma (rIFN-gamma) in the medium from the onset of culture maintained HLA-DR and DC antigen expression on a high number of cells (comparable to that observed on day 2 of culture). A large percentage of rIFN-gamma-treated cells also showed intracytoplasmic HLA-DR antigen expression. Addition of rIFN-gamma at various times after the onset of the culture led to a reinduction of DR and DC antigen expression. This effect of rIFN-gamma was observed in 48 hr with concentrations as low as 10 IU/ml and was apparently specific for this IFN species, in that rIFN-alpha was unable to modify HLA class II antigen expression at concentrations up to 1000 IU/ml. The increased expression of HLA class II antigen was truly due to induction in individual TEC, rather than selection of class II-positive cells, because induction under the influence of IFN-gamma was reversible and occurred in the absence of proliferation in mitomycin-treated or gamma-irradiated cultures. Our results indicate that synthesis and membrane expression of class II HLA antigens are enhanced by IFN-gamma in TEC cultures. This finding raises the possibility that IFN-gamma participates in the mechanisms that assure the permanent expression of DR and DC antigens observed in TEC in vivo, with potentially important functional consequences in terms of education for self recognition.
Cell Survival↗
Reinforcement and rapid delivery systems: understanding adverse consequences of cocaine.
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Cocaine↗
[Simultaneous appearance of precordial pain and effort-induced left bundle branch block. A study of 6 patients with normal coronary angiography].
6 patients, 4 men and 2 women, aged 38 to 60 years, were hospitalised for chest pain on effort, labelled as angina. The resting electrocardiogram was normal, except in 2 cases with incomplete left bundle branch block. Exercise stress testing induced simultaneous chest pain and complete left bundle branch block (LBBB) (at a rate of 15 to 160 beats/min, mean 115). The pain lasted as long as the LBBB was present and eased as it disappeared. All patients had normal coronary angiography and negative provocative tests of coronary spasm with atrial stimulation (4 cases), isoprenaline test (2 cases), atropine injection (2 cases) and nitroglycerin (1 case). A 2D echocardiogram performed in all the patients, showed no signs of myocardial disease. Myocardial perfusion on effort was studied by Thallium 201 scintigraphy in all 6 patients. There were no perfusion defects. An exercise stress test was performed after beta-blocker treatment in 3 patients. LBBB appeared each time and the pain was always present. The induction of bradycardia with propranolol (5 cases) or verapamil (3 cases) did not reduce the frequency of chest pain. No serious complications were observed during follow-up (myocardial infarction, death). The syndrome of painful LBBB is not related exclusively to tachycardia. Myocardial ischaemia does not seem to be the underlying mechanism judged by the negative thallium studies.
Adult↗
Na+/H+ exchange in volume regulation and cytoplasmic pH homeostasis in lymphocytes.
Osmotic shrinking activates an amiloride-sensitive Na+/H+ exchange in the membrane of blood and thymic lymphocytes. The exchange, which is virtually quiescent in isotonic conditions, can also be activated by lowering the cytoplasmic pH (pHi). Activation by pHi is largely caused by an allosteric interaction of H+ with a kinetic modifier site, different from the internal substrate site. The set point or threshold pHi for activation of the exchanger is dictated by the protonation of the modifier. Evidence is presented that indicates that cell shrinking alters the pHi sensitivity of the modifier, shifting the set point to more alkaline levels. In the presence of HCO3- and Cl- a volume increase will accompany the change in pHi. Volume changes can also be produced in isotonic solutions if the exchange is activated by acidification of the cytoplasm, e.g., by addition of propionate to the medium. The latter phenomenon provides a simple method for the detection of the Na+/H+ antiport by electronic cell sizing.
Amiloride↗
Significant metabolic acidosis induced by acetazolamide. Not a rare complication.
Blood gas and serum electrolyte levels were measured in 27 elderly patients (mean age +/- SD, 63.3 +/- 13.5 years) who were receiving acetazolamide (250 to 1,000 mg/day) for glaucoma. Eleven glaucomatous patients (mean age, 69.1 +/- 7.4 years) who were not receiving acetazolamide served as a control group. In the acetazolamide-treated group, four patients (14.8%) had mild acidosis (7.29 greater than pH less than or equal to 7.31), ten (37%) had moderate acidosis (7.20 greater than pH less than or equal to 7.29), and one patient (3.7%) had severe acidosis (pH, 7.15). None of the patients in the control group had acidosis. It is concluded that moderate metabolic acidosis of potential clinical significance is common among glaucomatous elderly patients who receive acetazolamide. The exact clinical significance of our observations is yet to be determined.
Acetazolamide↗
Retinal manifestations of thrombotic thrombocytopenic purpura (TTP) following use of contraceptive treatment.
An 18-year old woman, suffering from thrombotic thrombocytopenic purpura (TTP) disease after taking an oral contraceptive, developed bilateral retinal elevations in the posterior pole with Elschnig spot formation without visual acuity impairment. Clinical and laboratory evaluation combined with intensive medical and surgical therapy (splenectomy) caused regression of the ocular and general findings. We believe that the ocular pathologic findings in this clinical case are due to injury in the choroidal vasculature and the pe layer as a manifestation of the TTP disease.
Adolescent↗
A clinicopathologic case of cyclectomy for malignant melanoma of the ciliary body, complicated by total traction retinal detachment.
A case report is presented of a 43-year-old woman who underwent cyclectomy for malignant melanoma of the ciliary body of the left eye. One year after operation, the eye was enucleated because of inoperable total traction retinal detachment. The pathologic examination revealed no signs of local recurrence. At five-year follow-up, no systemic spread was found.
Adult↗
[Is it possible to predict the cleanliness of the colon before double-contrast enema? Study of the image of the abdomen without preparation, and the number of liquid stools].
Correlations between evaluations by two observers of cleanliness of colon on straight abdominal images (ASP) and on barium enema (LDC) results were studied, as well as predictions of cleanliness of LDC by ASP. Correlation between observers was practically nul for ASP and was poor for LDC. There is lack of correlation between cleanliness of colon on ASP and cleanliness of LDC. It is concluded that no purpose is served in performing ASP before LDC in order to predict cleanliness and that the definition of cleanliness itself requires updating. In contrast, however, the presence of less than three liquid stools appears to be related to diminished cleanliness (p less than 0.05).
Colon↗
Vascular distensibility and vascular surgery.
The elastic property of an arterial wall decreases considerably with aging and/or with a variety of pathological conditions. The resulting decrease in vascular compliance has a profound physiological effect on arterial perfusion. The objectives of this study were to assess a quantitative measure of peripheral vascular distensibility (D), to apply it in some clinical conditions, and to establish a potential means of predicting success in vascular surgery for limb salvage. A technique described earlier by us for the determination of D based on an accurate measurement of volume change (delta V) with pressure change (delta P) was further analyzed and then tested in four groups: the first two were non-surgical, 18 normal subjects, and 23 hypertensive men paired with 22 normotensive men; the last two were surgical, patients undergoing aortofemoral bypass (AFB) operations for limb salvage (salvaged vs unsalvaged); and patients who underwent below-knee amputations (BKA) for severe arterial insufficiency (healed vs unhealed). The results indicate that D can be used as a reliable assessment of the pathophysiological status of the arterial system in the lower extremity; furthermore, D can be used as a predictor of success in at least two types of vascular procedures: AFB with profundoplasty for limb salvage and BKA for severe arterial insufficiency.
Adult↗
Affinity of nortriptyline to muscarinic receptors in the bladder and ileum of man and guinea-pig.
The antagonism by nortriptyline of carbachol- or urecholine-induced contractions was studied in strips of ileum and bladder derived from man and guinea-pig. Analyses of the results by the dose ratio method (Schild plots) showed significant differences in the affinities of the relevant muscarinic receptors to the antagonist: The Ki values in microM were as follows: Human ileum, 0.938; human bladder, 0.298; guinea-pig ileum, 0.159; guinea-pig bladder, 0.333 and 0.453. In man, the higher affinity of the drug to the receptors in the bladder than to those in the ileum may be of consequence in its therapeutic application as an antienuretic agent.
Animals↗
Isolation of a calcium-dependent 35-kilodalton substrate for the epidermal growth factor receptor/kinase from A-431 cells.
We have isolated a soluble 35-kDa protein from A-431 cells that in the presence of calcium can serve as a substrate for the epidermal growth factor (EGF)-receptor/kinase. The purification procedure exploits the reversible, Ca2+-dependent binding of the 35-kDa protein to the A-431 total particulate fraction. The 35-kDa protein was purified by 1) Ca2+-dependent adsorption to A-431 particulate fractions, 2) release by chelation of Ca2+ with ethyleneglycolbis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid, and 3) chromatography on Sephadex G-100, DEAE-cellulose, and CM-cellulose columns. When a plasma membrane preparation from A-431 cells is used as a source of the EGF-receptor/kinase, the phosphorylation of the 35-kDa protein occurs on tyrosine, is greatly enhanced in the presence of EGF, and occurs only when Ca2+ is added to the standard reaction mixture for phosphorylation. Autophosphorylation of the receptor does not require Ca2+. We have postulated that one of the roles of Ca2+ is to facilitate the interaction of the 35-kDa protein with cellular membranes. Ca2+ enhances, but apparently is not essential for, the direct phosphorylation of the 35-kDa protein by the Triton X-100-solubilized, purified EGF-receptor/kinase. Incubation of intact A-431 cells with EGF at 37 degrees C (but not 0 degrees C) enhances the ability of the particulate fraction prepared from these cells to bind and/or phosphorylate the 35-kDa protein. We suggest that this enhancement in the phosphorylation of the 35-kDa protein, a presumed physiological substrate, is associated with the clustering and internalization of the EGF receptor/kinase complex.
Calcium↗
The intracellular pH of quiescent and proliferating human and rat thymic lymphocytes.
We compared the cytoplasmic pH (pHi) of quiescent and actively cycling thymic lymphocytes. Human and rat thymocyte suspensions were fractionated by centrifugation on one-step albumin density gradients. The pellet was composed of small, quiescent cells and the interphase contained mostly larger, actively cycling cells with a high proliferation index. When measured using [14C]-dimethyloxazolidinedione (DMO), pHi in the large cells of both species was approximately 0.15 units more alkaline than in the small cells. However, these differences were not detectable when pHi was measured with carboxylated fluorescein derivatives generated in situ by cytoplasmic enzymes. This apparent discrepancy can be explained by compartmentation of DMO, which accumulates in the alkaline mitochondrial matrix. Comparison of the mitochondrial content of quiescent and cycling thymocytes by several methods showed that the latter contained over 2.5-fold more mitochondria per unit cell volume. Assuming a constant intramitochondrial pH, this difference can account for the observed accumulation of DMO (i.e., apparent cytoplasmic alkalinity) in the actively proliferating cells. Therefore, no evidence was found for the existence of differences in pHi between quiescent and proliferating lymphocytes. Moreover, caution must be exercised when comparing DMO partition data in cells with varying relative mitochondrial content.
Animals↗
Percutaneous absorption of alkanoic acids I: A study of operational conditions.
The rate of penetration of propionic and butyric acids through excised porcine skin was determined in vitro in specific apparatus allowing optimal control of operational conditions. In one technique, the rate was followed by continuous pH-stat titration of acid appearing in the perfusate, in another, by periodic monitoring of [14C]propionic acid in the perfusate. With the assumption that Fick's equation applies to the process of penetration, it was found that the permeability coefficient, Kp, increases with increasing mass of neat penetrant applied per unit area to the donor side, increases with increasing concentration of penetrant in n-heptane as vehicle, increases with increasing temperature, Ea = 11.4 kcal/mol, and decreases with decreasing perfusion rate of the acceptor side when this rate is smaller than 60 mL/h.
Animals↗
Percutaneous absorption of alkanoic acids II: Application of regular solution theory.
The permeability coefficient, Kp, of pure unbranched alkanoic acids (C2-C7) applied to isolated porcine skin, reached a maximum in the solubility parameter (delta 2) range of 9.7-10 cal1 /2/cm3/2. When these and other penetrants were delivered from a solvent vehicle, the following linear relationships could be demonstrated: (a) between log Kp and the molar attraction constant of the penetrant [delta 2v2 or (-Ev)1/2] for six unbranched and six branched acids delivered from 1 M solution in n-heptane; (b) between Kp and the partial molal volume difference in n-heptane (-v2-v02) for the unbranched acids; and (c) between Kp and (-v2-v02) for propionic acid delivered from 1 M solutions in nine solvents having delta 1 values in the range 7.4-12.7 cal1 /2/cm3/2. Drug penetrability in a given series could be assessed from knowledge of the excess free energy of the penetrant in the delivery system used.
Animals↗
Mutations not altering the symmetrical sequences in the trp operator yield a constitutive phenotype.
An E. coli trp promoter operator mutant was constructed, having two base pair alterations at position -4 and -1 relative to the transcription initiation site (+1). Expression of chloramphenicol acetyltransferase gene under this trp promoter operator suggests that it is almost fully constitutive. This trp Oc in vitro derived mutant differs from previously isolated Oc mutants in that its twofold symmetry sequence is identical to that of the wild type trp operator. The base substitution in the operator does not affect the functionality of the trp promoter. The trp Oc promoter DNA fragment is engineered so that it can be manipulated conveniently for efficient expression of various genes in E. coli.
Acetyltransferases↗