Cycloheximide induces expression of the human interferon beta 1 gene in mouse cells transformed by bovine papillomavirus-interferon beta 1 recombinants

Mouse cells transformed by a bovine papillomavirus recombinant vector containing the human interferon (IFN) beta 1 (IFN-beta 1) gene could be induced to produce human as well as mouse IFNs. The optimal conditions for induction of human IFN and of its mRNA in these transformants resembled those needed for mouse IFN: high concentrations of DEAE-dextran and low concentrations of polyriboinosinic acid-polyribocytidylic acid. Superinduction by inhibitors of protein synthesis which strongly stimulate IFN-beta 1 induction in human cells had only a small effect on human IFN induction in bovine papillomavirus IFN-beta 1-transformed mouse cells. In contrast, cycloheximide without double-stranded RNA could induce significant levels of human IFN in the bovine papillomavirus IFN-beta 1 mouse transformants. After cycloheximide treatment, these cells contained IFN-beta 1 mRNA whose 5' ends originated in the authentic start site of the human IFN-beta 1 gene, as shown by S1 nuclease mapping. The transferred human gene, propagated extrachromosomally in the mouse cells, was, therefore, inducible under conditions different from those in human cells. The results also confirmed that the inhibitor of protein synthesis, cycloheximide, can induce expression of a human IFN gene.

Expression of human interferon genes using the recA promoter of Escherichia coli

Interferon beta 1 and three alpha-interferon genes were cloned on Eco RI fragments isolated from a human genomic library into the Eco RI site of a plasmid containing the recA promoter of E. coli. Expression of interferon activity from cells carrying these plasmids was nalidixic acid inducible. The alpha-interferon genes were expressed only when in the same transcriptional orientation as the recA promoter while the beta 1 interferon gene was expressed in either orientation. Interferon activity was also inducibly expressed from the recA promoter in cells containing a plasmid carrying a fusion of the recA gene with the beta 1 interferon gene. This interferon activity was thirty-fold less sensitive to neutralization by polyclonal antibodies than authentic interferon, implying that the change near the amino terminus affects either antibody recognition or specific activity or both.

Topological structure in visual perception

Three experiments on tachistoscopic perception of visual stimuli demonstrate that the visual system is sensitive to global topological properties. The results indicate that extraction of global topological properties is a basic factor in perceptual organization.

Synthesis of human interferon beta 1 in Escherichia coli infected by a lambda phage recombinant containing a human genomic fragment

DNA from a human adult was fragmented by partial digestion with restriction endonuclease EcoRI and cloned in lambda Charon 4A. Clone C15, with a human DNA insert of 17 X 10(3) bases, was identified as containing a gene for the fibroblast interferon, interferon beta 1. Restriction mapping shows that this gene, located on a 1840-base EcoRI fragment, is not interrupted by introns. Moreover, we show that this human genomic DNA fragment is able to direct the synthesis of active human interferon beta 1 in Escherichia coli. Interferon activity of up to 7 X 10(6) U/l was recovered from phage lysates by chromatography on Cibacron blue--Sepharose, and had the same immunological properties and species specificity as interferon produced by human fibroblasts.

Preoperative and postoperative echocardiographic studies of pulmonic valvular endocarditis

The echocardiographic manifestations of pulmonic valvular endocarditis in a patient with underlying heart disease consisting of a ventricular septal defect and infundibular stenosis are reported. The abnormal shaggy echoes observed on the pulmonic valve were confirmed to be vegetations based on surgical and pathologic findings. This was further proven by the disappearance of the shaggy echoes after surgical excision of the vegetations. We conclude that echocardiograms can detect the presence and disappearance of pulmonic valvular vegetations, which may be of aid in the diagnosis of pulmonic valvular endocarditis.

Adenosine 3',5'-monophosphate (cAMP)-binding proteins and cAMP-dependent protein kinases in bovine adrenal cortical cell plasma membrane

A cAMP-binding protein and cAMP-dependent protein kinase have been identified and partially characterized in bovine adrenocortical plasma membranes. [3H]cAMP binding to the plasma membrane preparation demonstrates both high (Ka = 4.2 X 10(9) M-1) and low (Ka = 1.3 X 10(8) M-1) affinity binding sites. cAMP-dependent protein kinase was demonstrated using both bovine histone and endogenous substrates. The detergent-dependent solubilization characteristics of this cAMP-dependent protein kinase indicate that it is an integral membrane protein.

Neurofibrillary change on Guam

Distribution and occurrence of neurofibrillary change (NFC) in the brain were studied in 114 Guamanians who had neither amyotrophic lateral sclerosis (ALS) nor parkinsonism dementia (PD). Comparison was made with 28 Guamanians with ALS-PD and 53 non-Guamanians without ALS-PD. Search for NFC was made in 15 dogs and cats that lived on Guam. Most of the Guamanians without ALS-PD during and after middle age had NFC similar to that of Guamanians with ALS-PD but lesser in degree and extent of involvement. It is possible that the general population of Guam had been exposed to the unknown etiologic agent of ALS-PD during some previous period.

Steroid receptors in human renal carcinoma

Glucocorticoid- and androgen-binding receptors were demonstrated in cytosol of human renal cell carcinomas by the dextran-coated charcoal technique. Sedimentation studies using preparative ultracentrifugation indicated a 7 to 8 S binding component. None of the renal carcinoma cells tested contained detectable estrogen receptors and a few samples had a very low but demonstrable progestin receptor level. In the normal kidneys tested, cytoplasmic components that bound only androgen could be detected. Competition studies showed that progestin competed for the glucocorticoid receptor sites in all the renal tumors tested, whereas diethylstilbestrol and testosterone were weak or not competitive. It is suggested that the response of some patients with renal carcinoma to high doses of progesterone or androgens could be explained by the ability of these hormones to block the activity of glucocorticoid receptors, which might be involved in tumor growth.

A testicular tumor with gingival metastasis

Testicular tumors comprise approximately 1 percent of all malignant neoplasms in the male. However, they are one of the more common malignant diseases of adolescent and young adult males. An unusual case of a testicular neoplasm in a 23-year-old man exhibiting gingival metastasis is presented.