Enhancer blocking activity located near the 3′ end of the sea urchin early H2A histone gene

The sea urchin early histone repeating unit contains one copy of each of the five histone genes whose coordinate expression during development is regulated by gene-specific elements. To learn how within the histone repeating unit a gene-specific activator can be prevented to communicate with the heterologous promoters, we searched for domain boundaries by using the enhancer blocking assay. We focused on the region near the 3′ end of the H2A gene where stage-specific nuclease cleavage sites appear upon silencing of the early histone genes. We demonstrated that a DNA fragment of 265 bp in length, defined as sns (for silencing nucleoprotein structure), blocked the enhancer activity of the H2A modulator in microinjected sea urchin embryos only when placed between the enhancer elements and the promoter. We also found that sns silenced the modulator elements even when placed at 2.7 kb from the promoter. By contrast, the enhancer activity of the modulator sequences, located downstream to the coding region, was not affected when sns was positioned in close proximity to the promoter. Finally, the H2A sns fragment placed between the simian virus 40 regulative region and the tk promoter repressed chloramphenicol acetyltransferase expression in transfected human cell lines. We conclude that 3′ end of the H2A gene contains sequence elements that behave as functional barriers of enhancer function in the enhancer blocking assay. Furthermore, our results also indicate that the enhancer blocking function of sns lacks enhancer and species specificity and that it can act in transient assays.     

Clonal B lymphocytes lack bcr rearrangement in Ph-positive chronic myelogenous leukaemia

Philadelphia (Ph) chromosome-positive chronic myelogenous leukaemia (CML) was studied in a subject heterozygous for the X chromosome-linked alloenzyme system of glucose-6-phosphate dehydrogenase (G6PD). Determination of G6PD mosaicism showed homogeneous expression in granulocytes, erythrocytes and platelets. Cytogenetic studies showed the typical Ph translocation in all metaphases from bone marrow and peripheral blood myeloid cells, bcr rearrangement was detected in bone marrow and in granulocytes. B cells were stimulated with Epstein-Barr virus (EBV) in order to evaluate involvement of lymphocytes, EBV-transformed lymphoblastoid cells expressed a single G6PD phenotype and therefore probably derived from the leukaemic stem cell. However they had a normal karyotype and a constitutional bcr restriction pattern. Molecular analysis in this case of CML clarifies the differentiative potential of cells belonging to the leukaemic clone, by demonstrating that clonal Ph-negative B cells maintain normal differentiative capacity and have a bcr gene sequence which is not rearranged.     

Cognitive correlates of under-ambiguity and under-risk decision making in high-functioning patients with relapsing remitting multiple sclerosis

Introduction: Impairment of decision making in relapsing remitting multiple sclerosis is still controversial, and its neuropsychological correlates have never been explored thoroughly, especially in patients with minimal physical and cognitive deficits. In the present study we investigated the cognitive underpinnings of decision making under ambiguous and explicit conditions in patients with very mild relapsing remitting multiple sclerosis, using a dice and a card gambling game. Method: The study sample included 60 patients and 35 healthy subjects. In the Game of Dice Task, winning and losing probabilities are obvious to the subject, while in the Iowa Gambling Task they are initially ambiguous and have to be gradually identified. Performance at the two tasks was correlated with scores obtained at tests investigating cognitive processing speed, memory, language and executive functions. Results: Patients’ performance did not differ from that of controls at either gambling task. There was only a trend for them to be significantly slower than healthy subjects in progressively recognizing advantageous decks in the Iowa Gambling Task. While the Game of Dice was unrelated to neuropsychological tests, predictors of performance at the Iowa task were Letter Fluency and the Symbol Digit Modalities Test for the initial, under-ambiguity, trials and the Wisconsin Card Sorting Test for the last, purely under-risk, trials. Conclusions: Our results suggest that high-functioning patients with relapsing remitting multiple sclerosis are substantially capable of making advantageous decisions, even if they may be slower in processing options and shifting strategy when selection criteria are not explicit.     

Application of Hydrogen Peroxide to the Control of Eutrophic Lake Systems in Laboratory Assays

We exposed water samples from a recreational lake dominated by the cyanobacterium Planktothrix agardhii to different concentrations of hydrogen peroxide (H₂O₂). An addition of 0.33 mg·L⁻¹ of H₂O₂ was the lowest effective dose for the decay of chlorophyll-a concentration to half of the original in 14 h with light and 17 h in experiments without light. With 3.33 mg·L⁻¹ of H₂O₂, the values of the chemical oxygen demand (COD) decreased to half at 36 and 126 h in experiments performed with and without light, respectively. With increasing H₂O₂, there is a decrease in the total and faecal coliform, and this effect was made more pronounced by light. Total and faecal coliform were inhibited completely 48 h after addition of 3.33 mg·L⁻¹ H₂O₂. Although the densities of cyanobacterial cells exposed to H₂O₂ did not decrease, transmission electron microscope observation of the trichomes showed several stages of degeneration, and the cells were collapsed after 48 h of 3.33 mg·L⁻¹ of H₂O₂ addition in the presence of light. Our results demonstrate that H₂O₂ could be potentially used in hypertrophic systems because it not only collapses cyanobacterial cells and coliform bacteria but may also reduce chlorophyll-a content and chemical oxygen demand.     

Comparison between rapid and mixed maxillary expansion through an assessment of dento-skeletal effects on posteroanterior cephalometry

Background

The aim of this study is to compare the dento-skeletal effects of rapid maxillary expansion (RME) and mixed maxillary expansion (MME), assessed on posteroanterior (PA) cephalograms.

Methods

Treatment groups consisted of 42 patients; mean age in RME group (n = 21,13 female and 8 male subjects) was 8.8 years ± 1.37 at T0 and 9.6 years ± 1.45 at T1 and mean age in MME group (n = 21, 12 female and 9 male patients) was 8.9 years ± 2.34 at T0 and 10.5 years ± 2.08 at T1. Seventeen bilateral anatomic landmarks, 16 linear (12 skeletal and 4 dental) and 4 angular measurements were assessed for each patient at T0 and T1. Data from the two groups were compared using independent sample t test (p < 0.05).

Results

At T0, the groups were similar for all examined variables (p > 0.05). Significant and equal increase of lateronasal and maxillary and upper and lower molar widths (p < 0. 01) occurred in both groups at T1. Significant but different increases were observed for maxillary incisal, upper left first molar-lateroorbitale, and maxillary first molar angles (p < 0.001 vs. p < 0.05). Significant increases were reported for upper inter-incisal width apex (p < 0.001) and upper right first molar-lateroorbitale angle (p < 0.05) only in the RME group. At T1, differences in maxillary incisal angle (p < 0.05), upper left first molar-lateroorbitale, and maxillary first molar angles (p < 0.001) were noted.

Conclusions

RME and MME were both effective to increase skeletal transverse dimensions by opening mid-palatal suture in growing patients, while MME was associated with minor dental side effects than RME.     

Left ventricular assist device implants in patients on extracorporeal membrane oxygenation: do we need cardiopulmonary bypass?

Open in a separate window OBJECTIVESImplanting a durable left ventricular assist device (LVAD) in a patient on extracorporeal life support (ECLS) is challenging. The goal of this study was to compare the results of patients from a European registry who had a durable LVAD implanted with or without transition from ECLS to cardiopulmonary bypass (CPB).METHODSA total of 531 patients on ECLS support who had an LVAD implant between January 2010 and August 2018 were analysed; after 1:1 propensity score matching, we identified and compared 175 patients in each group.RESULTSThe duration of preoperative ECLS was 7 [standard deviation (SD) 6] vs 7 (SD 6) days in patients with or without CPB (P = 0.984). The surgical time was longer in the CPB group [285 (SD 72) vs 209 [SD 75] min; P ≤ 0.001). The postoperative chest tube output was comparable [1513 (SD 1311) vs 1390 (SD 1121) ml; P = 0.3]. However, re-exploration for bleeding was necessary in 41% vs 29% of patients with or without CPB (P = 0.01) and a significantly higher number of packed red blood cells and fresh frozen plasma [8 (SD 8) vs 6 (SD 4) units; P = 0.001 and 6 (SD 7) vs 5 (SD 5) units; P = 0.03] were administered to patients operated on with CPB. A postoperative mechanical right ventricular support device was necessary in 50% vs 41% of patients (P = 0.08). The stroke rate was not significantly different (P 0.99). No difference in survival was observed.CONCLUSIONSOmitting CPB for an LVAD implant in patients on ECLS is safe and results in shorter operating time, less re-exploration for bleeding and fewer blood products. However, no survival benefit is observed.     

Metabolic,anthropometric, and psychological characteristics of obese binge eaters

This study examined the relationship of binge eating to a variety of metabolic, anthropometric, and psychological characteristics in 132 obese women seeking weight reduction. Contrary to findings of a reduced resting metabolic rate (RMR) in persons with bulimia nervosa, no significant differences were observed between obese bingers and nonbingers in RMR or thyroid hormones. Nor did the two groups differ significantly in weight, percentage body fat, body fat distribution, or serum lipid levels. Consistent with previous findings, however, binge eaters did score significantly higher in depression and other measures of psychopathology, as assessed by the Minnesota Multiphasic Personality Inventory. They also scored significantly higher in disinhibition and hunger but significantly lower in cognitive restraint. All of these findings await confirmation in subjects diagnosed according to criteria proposed for a new binge eating disorder. The present results, however, provide little support for the hypothesis that binge eating in obese individuals is related to reduced resting energy requirements. © 1993 by John Wiley & Sons, Inc.