Effect of beta-adrenergic blockers on the sickling phenomenon

Dichloroisoproterenol (DCI) and propranolol were found to inhibit sickling in vivo when they were added to red-cell suspensions prior to deoxygenation. The effectiveness was maximal between PO2's of 30 and 40 mmHg (1 mmHg = 133.322 Pa). When cells were sickled at a low oxygen tension (PO2 = 32 mmHg), and then DCI was added later, the drug decreased the degree of sickling while the suspension was maintained at the same oxygen tension. The antisickling effect of these drugs was not antagonized by isoproterenol, a beta-adrenergic stimulator, by the addition of cAMP or increase of the intracellular calcium concentration. Other beta-blockers, such as MJ1999 (sotalol) and timolol, did not show antisickling activity. It was also found that DCI, propranolol, and timolol had some effect on the delay time of gelation of sickle-cell hemoglobin (Hb S), as well as on the oxygen affinity of sickle cells.     

Vanadium-containing tunicate blood cells are not highly acidic

The intracellular pH of intact blood cells of the tunicate Ascidia nigra was measured by transmembrane equilibration of [¹⁴C]methylamine. The pH of unfractionated blood cells is 7.39±0.10. The pH of vanadocytes, determined in a fractionation study, is 7.2. Previously used methods, in which pH values less than 3.0 are inferred from cell lysis or vital staining experiments, are shown to be unsuitable for intracellular pH determination due to the chemical composition of these vanadium-containing cells.     

Arrangement of Integrated Avian Sarcoma Virus DNA Sequences Within the Cellular Genomes of Transformed and Revertant Mammalian Cells

We have examined the arrangement of integrated avian sarcoma virus (ASV) DNA sequences in several different avian sarcoma virus transformed mammalian cell lines, in independently isolated clones of avian sarcoma virus transformed rat liver cells, and in morphologically normal revertants of avian sarcoma virus transformed rat embryo cells. By using restriction endonuclease digestion, agarose gel electrophoresis, Southern blotting, and hybridization with labeled avian sarcoma virus complementary DNA probes, we have compared the restriction enzyme cleavage maps of integrated viral DNA and adjacent cellular DNA sequences in four different mouse and rat cell lines transformed with either Bratislava 77 or Schmidt-Ruppin strains of avian sarcoma virus. The results of these experiments indicated that the integrated viral DNA resided at a different site within the host cell genome in each transformed cell line. A similar analysis of several independently derived clones of Schmidt-Ruppin transformed rat liver cells also revealed that each clone contained a unique cellular site for the integration of proviral DNA. Examination of several morphologically normal revertants and spontaneous retransformants of Schmidt-Ruppin transformed rat embryo cells revealed that the internal arrangement and cellular integration site of viral DNA sequences was identical with that of the transformed parent cell line. The loss of the transformed phenotype in these revertant cell lines, therefore, does not appear to be the result of rearrangement or deletions either within the viral genome or in adjacent cellular DNA sequences. The data presented support a model for ASV proviral DNA integration in which recombination can occur at multiple sites within the mammalian cell genome. The integration and maintenance of at least one complete copy of the viral genome appear to be required for continuous expression of the transformed phenotype in mammalian cells.     

Regulation of mammalian protein synthesis in vivo. Protein synthesis in rat liver and kidney after the administration of sublethal doses of cyclohyximide.

Protein synthesis in vivo was studied at various times after the administration of sublethal doses of cycloheximide to rats. Cycloheximide caused an inhibition, followed by a dose-and time-dependent stimulation, of incorportation of labelled precursor into proteins of the liver and kidney. The stimulation of protein synthesis at 24h was not due to a change of precursor pool or the specific radioactivity of the precursor used. During the stimulatory period, leucine incorporation into various cellular protein fractions varied; incorporation into total nuclear protein was the most affected.     

Prostaglandin E2 on the electroencephalogram

Present study was prompted by the report from another center on the occasional occurrence of convulsions and abnormal electroencephalogram (E.E.G.) patterns in women aborted with intraamniotic prostaglandin F2α (PGF2α). Fifty four subjects were investigated by means of an E.E.G. taken before and after initiation of PGE2 administration. They included pregnant and non-pregnant patients, nearly half (23) of whom were known epileptics. One seizure was observed during PG administration in a man with daily psychomotor attacks who had not taken his anticonvulsants on the day the test was performed. PGE2 caused no alteration of the E.E.G. in subjects with a normal control tracing; in those with an abnormal E.E.G., a deterioration was seen in one and an improvement in three. It is concluded that PGE2 is not epileptogenic at doses required for termination of pregnancy.     

TBX2 acts as a potent transcriptional silencer of tumour suppressor genes through interaction with the CoREST complex to sustain the proliferation of breast cancers

Chromosome 17q23 amplification occurs in 20% of primary breast tumours and is associated with poor outcome. The TBX2 gene is located on 17q23 and is often over-expressed in this breast tumour subset. TBX2 is an anti-senescence gene, promoting cell growth and survival through repression of Tumour Suppressor Genes (TSGs), such as NDRG1 and CST6. Previously we found that TBX2 cooperates with the PRC2 complex to repress several TSGs, and that PRC2 inhibition restored NDRG1 expression to impede cellular proliferation. Here, we now identify CoREST proteins, LSD1 and ZNF217, as novel interactors of TBX2. Genetic or pharmacological targeting of CoREST emulated TBX2 loss, inducing NDRG1 expression and abolishing breast cancer growth in vitro and in vivo. Furthermore, we uncover that TBX2/CoREST targeting of NDRG1 is achieved by recruitment of TBX2 to the NDRG1 promoter by Sp1, the abolishment of which resulted in NDRG1 upregulation and diminished cancer cell proliferation. Through ChIP-seq we reveal that 30% of TBX2-bound promoters are shared with ZNF217 and identify novel targets repressed by TBX2/CoREST; of these targets a lncRNA, LINC00111, behaves as a negative regulator of cell proliferation. Overall, these data indicate that inhibition of CoREST proteins represents a promising therapeutic intervention for TBX2-addicted breast tumours.     

Measuring the unknown: An estimator and simulation study for assessing case reporting during epidemics

The fraction of cases reported, known as ‘reporting’, is a key performance indicator in an outbreak response, and an essential factor to consider when modelling epidemics and assessing their impact on populations. Unfortunately, its estimation is inherently difficult, as it relates to the part of an epidemic which is, by definition, not observed. We introduce a simple statistical method for estimating reporting, initially developed for the response to Ebola in Eastern Democratic Republic of the Congo (DRC), 2018–2020. This approach uses transmission chain data typically gathered through case investigation and contact tracing, and uses the proportion of investigated cases with a known, reported infector as a proxy for reporting. Using simulated epidemics, we study how this method performs for different outbreak sizes and reporting levels. Results suggest that our method has low bias, reasonable precision, and despite sub-optimal coverage, usually provides estimates within close range (5–10%) of the true value. Being fast and simple, this method could be useful for estimating reporting in real-time in settings where person-to-person transmission is the main driver of the epidemic, and where case investigation is routinely performed as part of surveillance and contact tracing activities.     

Simultaneous tissue profiling of eicosanoid and endocannabinoid lipid families in a rat model of osteoarthritis

We describe a novel LC method for the simultaneous and quantitative profiling of 43 oxylipins including eicosanoids, endocannabinoids, and structurally related bioactive lipids with modified acyl groups. The LC-MS/MS method uses switching at a defined time between negative and positive electrospray ionization modes to achieve optimal detection sensitivity for all the lipids. The validated method is linear over a range of 0.01–5 nmol/g (0.1–50 nmol/g for 2-arachidonoyl glycerol) with intra- and interday precision and accuracy between 1.38 and 26.76% and 85.22 and 114.3%, respectively. The method successfully quantified bioactive lipids in different tissue types in the rat, including spinal cord, dorsal root ganglia (DRGs), knee joint, brain, and plasma. Distinct regional differences in the pattern of lipid measured between tissue types were observed using principle component analysis. The method was applied to analyze tissue samples from an established preclinical rat model of osteoarthritis (OA) pain and showed that levels of 12-hydroxyeicosatetraenoic acid were significantly increased in the OA rat knee joint compared with controls, and that 15-hydroxyeicosatetraenoic acid was significantly increased in the DRGs in the model of OA compared with controls. The developed LC-MS/MS method has the potential to provide detailed pathway profiling in tissues and biofluids where the disruption of bioactive oxylipins may be involved in disease states.