Showing papers in "Experimental Biology and Medicine in 1970"
TL;DR: The use of human fibroblasts with an agarose overlay medium for the plaque assay of Herpesvirus hominis was found to be a reliable and practical method and this technique has now been modified for use in assaying cytomegalovirus (CMV) strains of human origin.
Abstract: The use of human fibroblasts with an agarose overlay medium was found to be a reliable and practical method for the plaque assay of Herpesvirus hominis (1). This technique has now been modified for use in assaying cytomegalovirus (CMV) strains of human origin. Two methods for the quantitation of cytomegalovirus have been described previously, in addition to the traditional determination of 50% tissue culture infectivity doses by tube dilution. The first of these, the microscopic counting of infected cells on coverslip preparations after either immunofluorescent (2) or Giemsa (3) staining had obvious limitations and technical difficulties. Plummer and Benyesh-Melnick (4) then described a plaque assay technique using methyl cellulose in the overlay medium. Since agarose overlays are more easily handled than methyl cellulose and afford a firm overlay to prevent viral spread, we investigated the use of an assay with two sequential agarose overlays. The criteria for a useful plaque assay described by Cooper (5...
278 citations
TL;DR: A simple physicochemical assay for the quantitation of enhanced vascular permeability in inflammation was described and it was shown that the assay is applicable to the study of inflammatory lesions induced with known chemical mediators and that associated with thermal injury.
Abstract: SummaryA simple physicochemical assay for the quantitation of enhanced vascular permeability in inflammation was described. It was shown that the assay is applicable to the study of inflammatory lesions induced with known chemical mediators, to the study of enhanced vessel permeability associated with the Arthus reaction, and that associated with thermal injury.
263 citations
TL;DR: A human cell line designated as SiHa has been established from cancerous tissues of the cervix uteri and the studies with light and electron microscopy have revealed the definite epithelial characteristics of the SiHa cells.
Abstract: SummaryA human cell line designated as SiHa has been established from cancerous tissues of the cervix uteri. The studies with light and electron microscopy have revealed the definite epithelial characteristics of the SiHa cells.
214 citations
TL;DR: Mouse granulopoietic progenitor cells can be detected by their capacity to form colonies in culture (CFU-C), and the degree to which their colony-forming capacity was destroyed following exposure to a pulse of high specific-activity 3HTdR is studied.
Abstract: SummaryMouse granulopoietic progenitor cells can be detected by their capacity to form colonies in culture (CFU-C). The proliferative state of these cells was studied by determining the degree to which their colony-forming capacity was destroyed following exposure to a pulse of high specific-activity 3HTdR. When marrow was obtained from normal adult mice 35% of CFU-C were inactivated by this procedure. In contrast, 80% of CFU-C were inactivated when cell populations were obtained from regenerating bone marrow. These results are interpreted to mean that CFU-C in normal mice are partitioned into two populations, one proliferating rapidly and the other slowly or not at all. In regenerating marrow the partition is changed, with all or almost all of the cells proliferating rapidly.
191 citations
TL;DR: The method has been applied to the iodination of bovine serum albumin, ovalbumin, Salmonella flagella, and other proteins and the minimum amount of chloramine-T required for acceptable iodination is determined.
Abstract: SummaryA method is described for the controlled iodination of proteins. The potential, EMF, of the reaction mixture is monitored and used to determine the minimum amount of chloramine-T required for acceptable iodination. The method has been applied to the iodination of bovine serum albumin, ovalbumin, Salmonella flagella, and other proteins.
181 citations
TL;DR: Development of two- to four-cell rabbit ova to the expanding blastocyst stage occurred in a simple glucose-salt solution supplemented with amino acids, and with 1.5% BSA as the only macromolecule, suggesting Hypoxanthine and/or thymidine may be inhibitory to good Blastocyst development.
Abstract: SummaryDevelopment of two- to four-cell rabbit ova to the expanding blastocyst stage occurred in a simple glucose-salt solution supplemented with amino acids, and with 1.5% BSA as the only macromolecule. However, optimum growth required the presence of vitamins. These experiments would indicate that although a uterine protein component may be necessary for blastocyst growth and expansion in utero, it is not necessary in the in vitro culture system used. Hypoxanthine and/or thymidine may be inhibitory to good blastocyst development, as the highest percentage of expanding blastocysts (63%) was obtained when the nucleic acid precursors were omitted.Thanks are due to Dr. R. R. Maurer and Mr. M. Simkin for technical assistance.
155 citations
TL;DR: The effect of cyclic AMP, its dibutyryl derivative and theophylline (an inhibitor of cyclIC AMP degradation) upon the stimulation of lymphocytes is studied.
Abstract: Shortly after polypeptide hormones act on target tissues, the tissues undergo a series of morphologic changes that can be related to the rearrangement of vacuolar systems. Thus thyroid-stimulating hormone induces endocytosis of thyroglobulin, parathyroid hormone induces the bulk exocytosis of lysosomal hydrolases and hydrogen ions from osteoclasts, glucagon stimulates the formation of autophagic vacuoles in liver, and melanophore-stimulating hormone induces the rearrangement of melanosomes in skin (1, 2). Since cyclic 3′, 5′-adenosine monophosphate (cA MP) has been implicated as the “second messenger” for these effects of hormones upon target tissues, it appeared possible that adenine nucleotides might regulate other functions of the vacuolar system in various cell types. Evidence suggesting that increments in the level of intracellular cAMP may inhibit granule flow and merger has been obtained by Lichtenstein and Margolis (3), who found that both theophylline and dibutyryl cyclic AMP (dcAMP) inhibited th...
144 citations
TL;DR: During the somite stages of rat embryogenesis glucose metabolism was high and its sharp decline with advancing age was associated with reduced lactate production, and by comparison of 14CO2 evolution rates from I-14C and 6-14Cs the pentose shunt pathway was shown to be active.
Abstract: SummaryDuring the somite stages of rat embryogenesis glucose metabolism was high. Its sharp decline with advancing age was associated with reduced lactate production. By comparison of 14CO2 evolution rates from I-14C and 6-14C-glucose the pentose shunt pathway was shown to be active.
136 citations
TL;DR: The results are interpreted to mean that a cholinergic synapse lies in the pathways which mediate water intake, whereas both cholinerential and adrenergic synapses may be involved in the mediation of salt and food intake.
Abstract: SummaryThe effects of microinjection of adrenergic and cholinergic drugs and hypertonic saline into the third ventricle on the intake of water, hypertonic salt (NaCl) solution, and food were studied. Carbachol induced a dramatic, rapid, 15-fold increase in water intake, whereas none of the other drugs were active. Both carbachol and isoproterenol evoked large increases in salt intake. Again, all other drugs failed to produce significant effects. Food intake was increased by the following adrenergic compounds: epinephrine, norepinephrine, metaraminol, isoproterenol, and dopamine. Carbachol was also effective in augmenting food intake but the effect was delayed. Hypertonic saline produced a delayed increase in both water and food intake but did not alter salt intake. The results are interpreted to mean that a cholinergic synapse lies in the pathways which mediate water intake, whereas both cholinergic and adrenergic synapses may be involved in the mediation of salt and food intake.
119 citations
TL;DR: It is concluded that norepinephrine operates to reduce secretion by limiting mucosal blood flow, and PGE1, which is a powerful vasodilator, reduces secretion by a primary mechanism other than restricting gastric mucosalBlood flow.
Abstract: SummarySecretion, mucosal blood flow, and the ratio (R) of blood flow to secretory rate were measured in conscious dogs provided with a gastric fistula. Secretion was stimulated to steady rates about one third of maximal with either pentagastrin or histamine. Prostaglandin E1 (PGE1) or norepinephrine was administered in doses of 0.1 or 1.0 μg kg-1 min-1. With the high dose of either agent, secretion was decreased, whether stimulated by histamine or pentagastrin, but the ratio of blood flow to secretory rate was decreased only with norepinephrine. It is concluded that norepinephrine operates to reduce secretion by limiting mucosal blood flow. On the other hand, PGE1, which is a powerful vasodilator, reduces secretion by a primary mechanism other than restricting gastric mucosal blood flow. The decrease in blood flow seen with PGE1 appears to be the result and not the cause of gastric secretory inhibition.I am indebted to Drs. Morton I. Grossman and Andre Robert for their critical comments and suggestions, ...
108 citations
TL;DR: Prostaglandin F2α was luteolytic in rhesus monkeys when injected 30 mg/day subcutaneously b.i.d. for 5 days, which indicates that the corpus luteum of this species is more vulnerable to lutenolysis in the later stages of the reproductive cycle.
Abstract: SummaryProstaglandin F2α was luteolytic in rhesus monkeys when injected 30 mg/day subcutaneously b.i.d. for 5 days, if the injections were initiated on day 11, 12, or 13 postovulation of fertile cycles. At this time circulating progestin levels are elevated, presumably due to a trophic stimulus from the blastocyst. Such an effect was not obtained by injection earlier in the luteal phase of the reproductive cycle. This indicates that the corpus luteum of this species is more vulnerable to luteolysis in the later stages of the reproductive cycle.
TL;DR: Candida albicans was stained with one of nine different indicator dyes which encompassed a pH range of 2.5-8.0 and living polymorphonuclear neutrophils were observed microscopically, and color changes of intracellular dye-stained Candida were noted.
Abstract: SummaryCandida albicans were stained with one of nine different indicator dyes which encompassed a pH range of 2.5-8.0. Living polymorphonuclear neutrophils were observed microscopically, and color changes of intracellular dye-stained Candida were noted. Intraphagosomal pH decreased to the 6.0-6.5 range and this pH change was prevented by certain glycolytic inhibitors.
TL;DR: A measles-related virus was isolated from two out of three brain biopsies of patients with SSPE by the fusion of brain cells with susceptible cells by using β-propiolactone-inactivated Sendai virus.
Abstract: SummaryA measles-related virus was isolated from two out of three brain biopsies of patients with SSPE by the fusion of brain cells with susceptible cells. β-propiolactone-inactivated Sendai virus was used in the fusion experiments. The mechanism of activation and the characterization of the isolated agents are discussed. Their association with another virus is reported in light of the etiology of SSPE.
TL;DR: Human serum and plasma have been shown to abolish the pyrogenicity of poly I:poly C and the inhibitory effects are time- and temperature-dependent and suggest that they are enzymatic in origin.
Abstract: SummaryHuman serum and plasma have been shown to abolish the pyrogenicity of poly I:poly C. Chicken serum and, to a lesser extent, fetal calf serum also possess this inhibitory effect, while serums of six other animal species do not alter the pyrogenic properties of this compound. The inhibitory effects are time- and temperature-dependent and suggest that they are enzymatic in origin.
TL;DR: In the isolated rat liver perfusion system, the immunological half-life of crystalline single-component insulin was 17 min, and there was no significant clearance of either proinsulin or the connecting peptide that links the A and B chain of insulin in the proins insulin molecule.
Abstract: SummaryIn the isolated rat liver perfusion system, the immunological half-life of crystalline single-component insulin was 17 min. In contrast, there was no significant clearance of either proinsulin or the connecting peptide that links the A and B chain of insulin in the proinsulin molecule. There was also no evidence of conversion of proinsulin to insulin. This may, in part, explain the prolonged in vivo half-life of proinsulin relative to insulin.The authors are most grateful to Dr. M. A. Root (Lilly) for the proinsulin antibody, and to Dr. R. E. Chance (Lilly) for the purified proinsulin, connecting peptide, and single-component insulin used in this study. We also appreciate the excellent technical assistance of Mrs. Carla Gullickson, Miss Ellen Laschansky, and Mrs. Jeanette Teague.
TL;DR: The antimetabolite, actinomycin D, is capable of enhancing the lethality of bacterial endotoxin in CFW mice over 100,000-fold and appears to offer a simple, reproducible, and highly sensitive test for the detection and quantitation of submicrogram amounts ofacterial endotoxin.
Abstract: SummaryThe antimetabolite, actinomycin D, is capable of enhancing the lethality of bacterial endotoxin in CFW mice over 100,000-fold. This procedure appears to offer a simple, reproducible, and highly sensitive test for the detection and quantitation of submicrogram amounts of bacterial endotoxin. The lethality in CFW mice of tetanus and diphtheria exotoxins was not similarly augmented by the antimetabolite. The procedure was capable of detecting small quantities of circulating endotoxin in rabbit blood 60 min after injection of 1 mg of S. typhosa endotoxin. Some characteristics and possible applications of this test are discussed.
TL;DR: In certain organs (brain, cerebellum, testis, Gasserian ganglion) histamine-type mediators are apparently unable to cause vascular leakage, suggesting that the selective response of the venules depends on an intrinsic property of the Venular wall, and not on the route whereby the mediator reaches the vessel.
Abstract: SummaryHistamine, serotonin, and bradykinin, injected intra-arterially, cause (in susceptible organs) vascular leakage predominantly from the venules. The vascular segments affected are the same as when the mediators are injected locally. This suggests that the selective response of the venules depends on an intrinsic property of the venular wall, and not on the route whereby the mediator reaches the vessel. In certain organs (brain, cerebellum, testis, Gasserian ganglion) histamine-type mediators are apparently unable to cause vascular leakage.
TL;DR: A method is described for the preparation of aortic intima-media samples which are free of adventitia and advantages of its use over the usual method of isolation are described in two types of application.
Abstract: SummaryA method is described for the preparation of aortic intima-media samples which are free of adventitia. Advantages of its use over the usual method of isolation are described in two types of ...
TL;DR: Polyriboinosinic–polyribocytidilic acid stimulated formation of hemolytic antibodies in mice immunized with sheep erythrocytes, and treatment with poly Ir:Cr resulted in a marked reduction in survival of isografts.
Abstract: SummaryPolyriboinosinic–polyribocytidilic acid stimulated formation of hemolytic antibodies in mice immunized with sheep erythrocytes. Similarly, poly Ir:Cr treatment of mice resulted in a marked reduction in survival of isografts. Temporarily, administration of poly Ir:Cr at the time of exposure of mice to antigen resulted in optimal enhancement of humoral and cellular antibody formation. Optimal enhancement of both humoral and cellular antibody formation was induced by 100-200 μg of poly Ir:Cr, while significant stimulation of hemolytic antibody formation was induced by a lower dose of 10 μg of poly Ir:Cr.We wish to thank Mr. Hugh Pettigrew of the Biometry Branch, National Cancer Institute, for the statistical evaluation of the experimental data.
TL;DR: It appears that the in vitro colony forming cell derives from a proliferating stem cell compartment, probably myeloid committed, and is distinct from the nonproliferating pluripotential transplantable stem cell.
Abstract: SummaryWhen bone marrow stem cells are assayed simultaneously by the spleen colony technique and the in vitro agar system following treatment of donors with hydroxyurea a differential effect was observed. There was found to be approximately a 50% reduction in the number of bone marrow in vitro colony forming cells after DNA synthesis inhibition by hydroxyurea and only a slight change in the pluripotential stem cell compartment by the spleen colony technique.It appears therefore that the in vitro colony forming cell derives from a proliferating stem cell compartment, probably myeloid committed, and is distinct from the nonproliferating pluripotential transplantable stem cell.
TL;DR: An in vivo method for measuring chemotaxis has been described using Millipore filters and demonstrated that soluble collagen, but not gelatin, was quite chemotactic.
Abstract: SummaryAn in vivo method for measuring chemotaxis has been described using Millipore filters. This method demonstrated that soluble collagen, but not gelatin, was quite chemotactic. Further, the products of collagenolysis produced by cutaneous collagenase, but not by bacterial collagenase, were extraordinarily chemotactic for polymorphonuclear leukocytes within 4 hr after testing at a concentration of about 0.1 μg.
TL;DR: The results support the concept of an important role of plasma FFA in controlling the pancreatic glucagon production, at least in dogs.
Abstract: SummaryArtificial changes in plasma FFA concentrations were induced in dogs by infusion of nicotinic acid and of triglycerides with added heparin. In all experiments, the fall in plasma FFA observed during the nicotinic acid infusion or after terminating the TG-heparin infusion was accompanied by an increase in pancreaticoduodenal venous plasma glucagon concentrations corresponding to a true increase in pancreatic glucagon production. These results support the concept of an important role of plasma FFA in controlling the pancreatic glucagon production, at least in dogs.We express our gratitude to Drs. V. Marks and A. E. Renold for reviewing this manuscript and for helpful criticism, and to Mrs. Cartenstadt and Mrs. Burguet for their expert technical assistance.
TL;DR: It is made that the activity of ribonucleotide reductase may be a limiting factor in the replication of certain members of the herpesvirus group.
Abstract: SummaryThe thiosemicarbazones of 2-formylpyridine, 3-formylpyridine, 4-for-mylpyridine, 5-hydroxy-2-formylpyridine, 1-formylisoquinoline, 5-hydroxy-1-formylisoquinoline, 6-formylpurine, isatin, and 1-methylisatin were examined for activity against herpes simplex virus in HEp−2 cells and human cytomegalovirus in WI-38 cells, and also for inhibition of ribonucleotide reductase activity in HEp−2 cells A correlation was seen between inhibition of reductase and antiviral activity, with those compounds having the -CH=N-NH-C(=S) -NH2 moiety affixed to the heterocyclic ring system in the position alpha to the ring nitrogen being active The suggestion is made that the activity of ribonucleotide reductase may be a limiting factor in the replication of certain members of the herpesvirus group
TL;DR: Zinc-deficient animals to be inferior when compared to zinc-supplemented subjects and the relationship between zinc and protein utilization was posited as a possible mechanism explaining the effects of zinc insufficiency.
Abstract: Summary and ConclusionsBehavioral measures were obtained for rats administered a zinc deficient diet, (8.0 mg/kg) and adequate in all other constituents, for 48 days beginning at 30 days of age. Pair-fed controls received a zinc-supplemented diet (70 mg/kg of total zinc). Lethargy and reduced weight gain were characteristic of all zinc-deficient subjects. Performance on two measures of learning ability (viz., a one-way conditioned avoidance test and an eight-blind water maze) and an test of activity-emotionality (viz., the open-field test) revealed zinc-deficient animals to be inferior when compared to zinc-supplemented subjects. The relationship between zinc and protein utilization was posited as a possible mechanism explaining the effects of zinc insufficiency.
TL;DR: A similar platelet lesion was produced by an acetylating agent, acetic anhydride, supporting earlier concepts that aspirin activity against platelets may be a consequence of acetylation.
Abstract: SummaryAspirin produces alteration of platelet function characterized by loss of secondary aggregation in response to ADP or epinephrine, and inhibition of aggregation by collagen. In addition, platelet factor 3 release by these reagents is reduced. A similar platelet lesion was produced by an acetylating agent, acetic anhydride, supporting earlier concepts that aspirin activity against platelets may be a consequence of acetylation. An attempt to identify specific acetylation of platelets with acetyl-1-14C salicylic acid was unsuccessful. Although platelet uptake of the label was demonstrated, metabolic incorporation of acetate could not be excluded.
TL;DR: Seven healthy subjects were exposed to imaginary food ingestion under hypnotic stimulus and plasma glucose, immunoreactive insulin and NEFA were measured during the experiment and three subjects showed elevation in plasma insulin either after the induction of “hunger” or after the beginning of the “meal.”
Abstract: SummarySeven healthy subjects were exposed to imaginary food ingestion under hypnotic stimulus and plasma glucose, immunoreactive insulin and NEFA were measured during the experiment. Three subjects showed elevation in plasma insulin either after the induction of “hunger” or after the beginning of the “meal.” Fall in NEFA was seen in four subjects. No changes in blood glucose were detected.
TL;DR: It is concluded that the β-cytotoxic effect of streptozotocin is not immediately irreversible or that it does not affect all B-cells simultaneously; that the insulin release observed between 6 and 10 hr after the injection of strePTozotOCin occurs by way of leakage from damaged B- cells; and that streptozootoc in and alloxan differ in their mechanism of action on the pancreatic B-cell.
Abstract: SummaryFurther studies on the mode of action of streptozotocin and the prevention of its effects by nicotinamide have yielded the following results: 1. The injection of nicotinamide at varying time intervals after streptozotocin afforded partial protection against its β-cytotoxic effects, decreasing with the length of the intervals but still significant when the interval was 2 hr. 2. Manno-heptulose failed to suppress the insulin release occurring between 6 and 10 hr after the injection of streptozotocin. 3. Nicotinic acid administered by gastric tube failed to protect against the diabetogenic effect of streptozotocin. 4. Nicotinamide injected 10 min after alloxan afforded no protection against the diabetogenic effect of the latter. It is concluded (1) that the β-cytotoxic effect of streptozotocin is not immediately irreversible or that it does not affect all B-cells simultaneously; (2) that the insulin release observed between 6 and 10 hr after the injection of streptozotocin occurs by way of leakage fro...
TL;DR: Plasma renin activity and reninactivity content in several tissues of dogs under conditions of severe sodium restriction, congestive heart failure, clipping of one renal artery, and nephrectomy were studied and compared to the values obtained in control dogs.
Abstract: SummaryPlasma renin activity and renin activity content in several tissues of dogs under conditions of severe sodium restriction, congestive heart failure, clipping of one renal artery, and nephrectomy were studied and compared to the values obtained in control dogs. The highest extrarenal RAC was found in adrenal glands followed by liver, spleen, heart, lung, skeletal muscle, and arterial tissue. Severe chronic sodium restriction increased RAC in all tissues, with the exception of the adrenal glands and aorta; whereas, the RAC following nephrectomy did not decrease significantly. In renovascular hypertension secondary to unilateral renal clipping, there is a slight, but not significant, increase in RAC in adrenal glands.
TL;DR: Singh's mosquito cell line derived from larval A. albopictus was found to be adaptable to various partially defined growth media and unaffected by noncytotoxic doses of actinomycin-D.
Abstract: SummarySingh's mosquito cell line derived from larval A. albopictus was grown in spinner cultures with a doubling time of 24-30 hr at 23 or 28°. It was found to be adaptable to various partially defined growth media. The typical chromosome count was 6, with 12 chromosomes appearing in 25% of figures. Infection of the cells with Sindbis virus or type 2 dengue virus at multiplicities of 1 or 2 pfu/cell and maintenance at 28° yielded viral growth cycles similar in timing to those seen in infected vertebrate cells at 37°. Cells chronically infected with Sindbis virus yielded virus at the rate of 1 pfu/cell/-day 7 weeks after infection. Sindbis virus production by cells exposed to actinomycin-D was unaffected by noncytotoxic doses. CPE due to actinomycin occurred at concentrations similar to those affecting vertebrate cells.
TL;DR: The results demonstrate a conditioned release of some hypoglycemic agent that depends upon the integrity of the beta cells, and a neural control over release of insulin must be inferred to explain them.
Abstract: SummaryAlthough the phenomenon of conditioned hypoglycemia is now well established, little is known about its mechanism. The present experiments lead to the conclusion that the mechanism involves a release of insulin: Experiment 1 showed that rats given an injection of streptozotocin, a drug which destroys the beta cells of the islets of Langerhans, did not show a conditioned hypoglycemia, whereas rats given only the vehicle for the streptozotocin did; and in experiment 2, blood drawn from conditioned rats just before the conditioned hypoglycemia would normally occur showed greater insulinlike activity than blood drawn from control rats. These results demonstrate a conditioned release of some hypoglycemic agent that depends upon the integrity of the beta cells. A neural control over release of insulin must be inferred to explain them.This study was supported by the USPHS Training Grant No. 5TO1 GM 00666. Thanks are due to Dr. Clara A. Muehlbaecher and to Dr. Daniel Porte, Jr. for their helpful comments; t...