Cell-free translation of avian erythroblastosis virus RNA yields two specific and distinct proteins with molecular weights of 75,000 and 40,000

Avian erythroblastosis virus (AEV) 28 S virion RNA was translated in vitro in cell-free reticulocyte lysates. Two AEV-specific proteins, one of 75,000 (p75) the other of 40,000 (p40) molecular weight, were detected. p75 is a fusion protein containing gag-specific and AEV-specific peptides. It appears to be translated from the 5′-end of the 28 S AEV RNA and is indistinguishable from the p75 detected in AEV-transformed cells (Hayman et al., 1979). p40 does not share sequences with any viral structural protein. It also contains peptides distinct from those of p75, but one of the five identifiable p40 peptides comigrates with one of the p75 peptides. p40 is translated from a 20 S RNA which contains the 3′-half of the AEV-specific sequences of the genome. These two proteins account for all of the coding capacity of the AEV-specific gene sequences in the 28 S AEV RNA and are candidates for leukemia-specific transforming proteins.     

SV40 virus particles lack a psoralen-accessible origin and contain an altered nucleoprotein structure

The nucleoprotein structure of SV40 virions was examined by photolabeling purified virus with the radioactive psoralen derivative hydroxymethyltrimethylpsoralen (HMT). Unlike SV40 chromatin in situ, the viral origin region is not preferentially accessible to drug addition. The ratio of the distribution of radioactivity in the DNA restriction fragments of virion DNA to that of purified SV40 DNA demonstrates that the photoadducts are positioned similarly on the circular molecule in both samples. Virion purified from infected cells was also analyzed for the presence of an open region and found to exhibit the same pattern of [3H]HMT addition as mature extracellular virion. The nucleosome-free region detected at the SV40 replication origin in intracellular minichromosomes is not present in either population of intact virus particles. We also examined the level of drug addition obtained when purified virion or SV40-infected cells were treated with saturating doses of [3H]HMT. Marked differences in the plateau levels of bound drug indicate that an altered nucleoprotein structure exists in SV40 virions that does not protect the DNA from photoaddition to the same extent as do the nucleosomes of intracellular SV40 DNA.     

Airway responses to antigen challenge in allergic rhinitis and allergic asthma

The density dependence of the maximum expiratory flow-volume curve, functional residual capacity (FRC), and specific airway conductance (SGaw) were determined before and during bronchial provocation with ragweed extract in 27 subjects with ragweed hypersensitivity and a history of either bronchial asthma (16 subjects) or allergic rhinitis (11 subjects). Mean baseline SGaw was significantly lower while mean volume of isoflow (Visov) and FrC were significantly higher in subjects with bronchial asthma. During antigen challenge, 10 of 16 subjects with bronchial asthma (63%) and five of 11 subjects with allergic rhinitis (45%) showed a greater than 35% decrease in SGaw ("reactors"): mean relative decreases in SGaw from baseline were 46% and 53%, respectively. The remaining subjects showed a less than 35% decrease in SGaw ("nonreactors") with mean relative decreases of 9% (allergic asthma) and 6% (allergic rhinitis). Mean Visov increased in all subjects with bronchial asthma and in eight of 11 subjects with allergic rhinitis. A significant increase in FRC (6%) was seen only in the "reactors" with bronchial asthma. Following antigen challenge, the beta adrenergic agonist, isoetharine, increased SGaw and decreased Visov. We conclude that in asymptomatic subjects with ragweed hypersensitivity, (1) central and peripheral airway function is more abnormal in subjects with bronchial asthma than in subjects with allergic rhinitis, (2) subjects of both groups show quantitatively and qualitatively comparable airway responses during antigen challenge with a decrease in SGaw or an increase in Visov, possibly representing increase in central and/or peripheral airflow resistance, respectively, (3) Visov may be a more sensitive indicator of airway response to antigen challenge than SGaw, and (4) the bronchodilator effects of a beta adrenergic agonist on antigen-induced bronchospasm are similar in both groups.     

A simple bactericidal antibody test for sero-diagnosis of typhoid fever

Serum samples were collected from 24 confirmed cases of typhoid fever, 15 clinically suspected cases and 23 normal healthy controls. The convalescent sera were obtained in 13 of the 24 confirmed typhoid cases. In all, 13 paired sera, 11 acute phase only, 15 clinically suspected and 23 normal serum samples were tested for eliciting bactericidal antibodies to Salmonella typhi. In addition, the Widal test was also performed for comparison. All the 24 acute phase sera as well as 13 convalescent sera were found to be positive by bactericidal antibody test (titre 1:80 or above). Of 15 clinically suspected cases, 5 were positive whereas one of the 23 normal controls sera gave a false positive reaction. In contrast, the Widal test could detect only one of the 24 cases in the acute stage, but all 13 cases showed antibodies at a diagnostic titre level during the convalescent stage. None of the 15 clinically suspected cases or 23 normal controls were positive by the Widal test. The feasibility of using a bactericidal antibody test in sero-diagnosis of typhoid fever is discussed.     

Effects of theophylline,terbutaline, and prednisone on antigen-induced bronchospasm and mediator release

Eleven subjects demonstrating clinical, skin, and inhalation sensitivity to grass or ragweed pollen underwent serial inhalation challenges, with and without orally administered theophylline, terbutaline, and prednisone. Comparisons of antigen sensitivity and mediator release were made during these challenges. All three drugs significantly reduced antigen sensitivity (PD₂₀ inhalation units increasing from 670 to ≧ 3,280). Peak plasma histamine levels after antigen challenge decreased from 11.4 ng/ml to ≦ 3.4 ng/ml during all drug administrations. Similarly, the percent increase in serum neutrophil chemotactic activity (NCA) also decreased, from 96% to ≦ 36% during drug administrations. However, even at antigen doses resulting in bronchospasm during drug administration the systemic appearance of NCA and histamine were reduced. We conclude that prednisone, theophylline, and terbutaline significantly reduce antigen-induced bronchospasm and mediator release. The occurrence of bronchospasm despite the inhibition of histamine and NCA suggests either that the local concentration of these mediators are critical or that other mediators produce the bronchospasm observed.     

Na+,K+-activated adenosine triphosphatase of isolated Müller cells from the rabbit retina shows a K+ dependence similar to that of brain astrocytes

Müller (glial) cells from the rabbit retina were isolated by means of papain and mechanical dissociation. Their Na+,K+-adenosine triphosphatase (ATPase) activity was measured using a radiochemical method, and its K+ dependence was determined. In contrast to that of photoreceptors (data from the literature), the Na+,K+-ATPase of Müller cells could be shown to increase its activity greatly when the [K+] was enhanced up to 10 mM. The functional implications of this behaviour for the K+ clearance in the retina are discussed.     

Glucose preferences in wild and domestic guinea pigs

Male wild (Cavia aperea) and domestic (C. porcellus) guinea pigs were tested in two-bottle choice tests for preferences between glucose solutions of different concentrations and de-ionized water. Wild males showed significant preferences for concentrations between 0.025 and 0.4 M glucose while domestic males preferred only the 0.2 M glucose solution to de-ionized water. C. aperea males also consumed significantly greater volumes of liquid per kg body $\text{wt.}{}^{\mathrm{<mtext>3</mtext><mtext>4</mtext>}}$ during the glucose tests than did the C. porcellus males. These comparative results contrast sharply with those obtained by other authors with wild and domestic Norway rats.     

Adenovirus type 12 tumor antigen. II. Immunoprecipitation of protein kinase from infected and transformed cells by antisera to T antigen and some normal rat sera.

Protein kinase was found to be precipitated from adenovirus type 12 (Ad12)-infected KB cells and Ad12-transformed hamster cells by sera of tumor-bearing hamsters and rats: Immunoprecipitates obtained with T antigen reactive sera catalyzed transfer of ³²P from [γ-³²P]ATP to the γ-chain of IgG. Analogous products of control cells were without significant activity. Control hamster sera precipitated no protein kinase from infected and transformed cells. Some control rat sera (syngeneic with immune sera), however, were found to precipitate protein kinase from infected and transformed cells; particularly active in this respect were sera of female breeder rats. When partially purified, highly immunoreactive T antigen preparations from transformed cells were used as a source of enzymatic activity, protein kinase was detected only in precipitates obtained with immune sera.     

Benzylpenicillin preparations can evoke a systemic anaphylactic reaction in guinea pigs

All of the five commercially available benzylpenicillin preparations obtained from different sources and a PcG preparation prepared by filtration of a commercial PcG on Sephadex G10 elicited the systemic anaphylactic reactions in guinea pigs which had been immunized with benzylpenicilloyl (BPO)-Ascaris extract conjugate (BPO-As) mixed with aluminum hydroxide gel. These preparations could evoke no such reactions in guinea pigs immunized with BPO-bovine gamma globulin conjugate (BPO-BGG) emulsified with complete Freund's adjuvant. The severity of the systemic anaphylactic reactions correlated significantly with the titers of either 8-day passive cutaneous anaphylactic (8-day PCA) reactions or 4-hr PCA reactions evoked with the same benzylpenicillin preparations. In vitro benzylpenicillin preparation contracted the tracheas of the guinea pigs immunized with BPO-As. These results indicated that the commercially available benzylpenicillin preparations have enough antigenicity to evoke systemic anaphylactic reactions in guinea pigs immunized with BPO-As mixed with aluminum hydroxide gel. Such guinea pigs represent an animal model for investigation of penicillin allergy.