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.

Differentiation of decidual cells in cultures of rat endometrium

Endometrial scrapings were collected from rat uteri at various times (0-4 days) after induction of a decidual reaction by i.p. injection of pyrathiazine hydrochloride (20 mg/animal) on the 5th day after a sterile mating. The tissue was dissociated by treatment with trypsin and the cells were cultured as monolayers. The differentiation of decidual cells was followed in these cultures. Two morphologically distinct cell populations were recognized: (i) dispersed spindle-shaped or stellate cells, and (ii) colonies of closely packed polygonal cells, first apparent after 48 h in culture. During culture, [3H] thymidine was incorporated into the nuclei of both cell types, as indicated by autoradiography. There was an increase in the number of cells in the colonies as culture progressed; most mitotic figures and the highest % of labelled nuclei were located within the colonies. Bi- and multinucleated cells, which are a characteristic feature of decidual tissue in vivo, appeared in the colonies on the 3rd day of culture and constituted about 60% of the colony population after 4-5 days. The dispersed cells showed a doubling in nuclear area during 4 dyas in culture, suggesting the formation of polyploid cells; such cells are prominent in fully differentiated decidual cells in vivo. The content of prostaglandin E in the cultured cell, determined by radioimmunoassay, was about 15-fold higher than that in rat embryo fibroblast cultures grown under similar conditions, and was comparable to the level of prostaglandins found in decidual cells in vivo.

Habituation and inhibition of the crayfish lateral giant fibre escape response

1. Decrement of the lateral giant fibre escape response was studied in intact, restrained, crayfish and in those with the ventral nerve cord transected at the thoracic-abdominal level. 2. Taps (delivered at rates of 1 per 5 min to the abdomen) depressed responsiveness to about 50% of its inital value in 10 trials, for both intact and operated animals. 3. With additional stimulation, responsiveness dropped to near zero for both groups. Recovery was negligible 2 h later, but nearly complete after an additional 24 h rest. 4. Protection against response decrement in this situation was obtained by directly activating the cord giant fibres 30 msec prior to the tactile stimulus. The directly-elicited giant fibre spikes which follow the tactile stimulus do not influence the course of response decrement. 5. The results establish the decrement as centrally mediated habituation, and minimize the role of receptor alterations or descending neuronal influences in the behavioural change. 6. A comparison is made between the properties of hibituation and the homosynaptic depression of afferent to interneurone synapses that is presumed to be the physiological mechanism of habituation in this situation.

Mitogenic action of oestradiol-17 beta on human myometrial and endometrial cells in long-term tissue cultures

Dispersed human endometrial and myometrial cells grown for up to 4 months as monolayer cultures responded to addition of oestradiol-17β (1 × 10−9 mol/l) to the medium by increased [3H]thymidine incorporation into DNA, and an increased rate of cell division. Cultures derived from uterine leiomyomata showed a less consistent mitotic response to the hormone.

Normal endometrial and myometrial cells grown in the oestradiolenriched medium showed a significantly higher efficacy of colony formation (increases of about 60 and 90%, respectively) than cells grown in control medium throughout the experimental period. Exposure to the hormone for 3–4 days was sufficient to induce this effect, which suggests that it does not depend on selection of hormone-sensitive cells. The mitogenic effect of oestradiol, as expressed by increased cloning efficacy, persisted for several days after transfer of the cells to a hormone-free medium. Cultures of foetal rat skeletal muscle failed to respond to oestradiol-17β in the cloning test, and oestradiol-17α was without effect on uterine cells.

It is concluded that oestradiol-17β exerts a direct mitogenic action on some cellular components of the human endometrium and myometrium in vitro.

Further studies of the effect of bone marrow cells on chemically induced lymphoma in C57BL-6 mice

Injection of syngeneic bone marrow cell to adult C57BL/6 mice treated DMBA intragastrically failed to prevent lymphoma induced by the chemical.The present result seem to indicate that bone marrow cells do not hasten the regeneration of the transient injuried thymus by DMBA as compared with their effect in irradiated mice.IT APPEARS THAT, UNDER THE CONDITIONS USED, DMBA DOES NOT CAUSE SIGNIFICANT DAMAGE TO THE BONE MARROW SINCE MARROW CELLS FROM CHEMICALLY TREATED MICE WERE AS EFFECTIVE AS NORMAL MARROW CELLS IN: (a) preventing radiogenic leukaemia, (b) repairing radiation damage of the thymus, (c) preventing the lethal action of high doses of irradiation.Marrow cells failed to restore antibody formation to Shigella depressed by DMBA as they do in irradiated mice.The result strengthen our previous view on the critical role of bone marrow on the effects caused by irradiation and not in the leukaemia process as such.

Investigations of the marine algae of Nova Scotia. VIII. The flora of Digby Neck Peninsula, Bay of Fundy

The algal flora at two selected sites on the Digby Neck Peninsula, Bay of Fundy, was examined at monthly intervals for a year. One hundred and eighty-seven species and varieties were recorded; of these 76 are newly recorded for the Bay of Fundy and 11 are new records for North America. A taxonomic listing, inclusive of reproductive structures found during the year, is given. Seasonal changes and vertical migration of the algae are discussed.

SPORANGIA OF RALFSIA FUNGIFORMIS (GUNN.) SETCHELL ET GARDNER(1) (2)

Unilocular and plurilocular sporangia of Ralfsia fungiformis are, for the first time, recorded for North America. The validity of certain types of structures, considered by some authors as plurilocular sporangia, is discussed.