Effect of soluble copper released from copper oxide nanoparticles solubilisation on growth and photosynthetic processes of Lemna gibba L

Copper oxide nanoparticles (CuO NPs) are used as a biocide in paints, textiles and plastics. Their application may lead to the contamination of aquatic ecosystems, where potential environmental effects remain to be determined. Toxic effects may be related to interactions of NPs with cellular systems or to particles' solubilisation releasing metal ions. In this report, we evaluated CuO NPs and soluble copper effects on photosynthesis of the aquatic macrophyte Lemna gibba L to determine the role of particle solubility in NPs toxicity. When L. gibba plants were exposed 48 h to CuO NPs or soluble copper, inhibition of photosynthetic activity was found, indicated by the inactivation of Photosystem II reaction centers, a decrease in electron transport and an increase of thermal energy dissipation. Toxicity of CuO NPs was mainly driven by copper ions released from particles. However, the bioaccumulation of CuO NPs in plant was shown, indicating the need to evaluate organisms of higher trophic level.     

Serum immunoglobulin levels following allogeneic bone marrow transplantation

Summary In order to study the posttransplant evolution of serum immunoglobulin levels, we measured serum IgG, IgA and IgM levels in 50 recipients of allogeneic bone marrow before transplantation and at different intervals thereafter (days 39, 120, 365 and 730). IgG and IgM levels were depressed for 1 year and IgA levels for 2 years posttransplant. Immunoglobulin deficiency was more severe and prolonged in patients with graft versus-host-disease. Hypogammaglobulinemia may contribute to the frequent infections observed in these patients, especially those with chronic graft-versus-host disease.     

Therapy-induced preleukaemia in patients treated for Hodgkin''s lymphoma: clinical and therapeutic relevance of sequential chromosome banding studies

Between January 1978 and December 1982 successful sequential chromosome analyses were carried out on bone marrow cells of five patients previously treated for Hodgkin's lymphoma (HL) presenting unexplained cytopenia or pancytopenia during follow-up. All patients had concurrent morphological examination of bone marrow specimens showing signs of dysplasia and/or hypoplasia, without leukaemic infiltrate. Six other patients treated for HL who had normal haematological parameters served as controls. All the patients with unexplained cytopenias had clonal chromosome abnormalities; monosomy for chromosome No. 5 was the most frequent. No abnormalities were detected in the control group. Two patients have evolved to resistant leukaemia, one died of sepsis before leukaemic conversion while severely neutropenic, and two are in full marrow and cytogenetic recovery after aggressive anti-leukaemic treatment in the pre-leukaemic phase. Our data suggest that cytogenetic studies may be of crucial value in detecting therapy-induced preleukaemia (t-PL) at an early stage of its evolution and in planning appropriate therapy before the establishment of overt leukaemia.     

Sex differences in innate and adaptive neural oscillatory patterns link resilience and susceptibility to chronic stress in rats

BackgroundMajor depressive disorder is a chronic illness with a higher incidence in women. Dysregulated neural oscillatory activity is an emerging mechanism thought to underlie major depressive disorder, but whether sex differences in these rhythms contribute to the development of symptoms is unknown.MethodsWe exposed male and female rats to chronic unpredictable stress and characterized them as stress-resilient or stress-susceptible based on behavioural output in the forced swim test and the sucrose preference test. To identify sex-specific neural oscillatory patterns associated with stress response, we recorded local field potentials from the prefrontal cortex, cingulate cortex, nucleus accumbens and dorsal hippocampus throughout stress exposure.ResultsAt baseline, female stress-resilient rats innately exhibited higher theta coherence in hippocampal connections compared with stress-susceptible female rats. Following stress exposure, additional oscillatory changes manifested: stress-resilient females were characterized by increased dorsal hippocampal theta power and cortical gamma power, and stress-resilient males were characterized by a widespread increase in high gamma coherence. In stress-susceptible animals, we observed a pattern of increased delta and reduced theta power; the changes were restricted to the cingulate cortex and dorsal hippocampus in males but occurred globally in females. Finally, stress exposure was accompanied by the time-dependent recruitment of specific neural pathways, which culminated in system-wide changes that temporally coincided with the onset of depression-like behaviour.LimitationsWe could not establish causality between the electrophysiological changes and behaviours with the methodology we employed.ConclusionSex-specific neurophysiological patterns can function as early markers for stress vulnerability and the onset of depression-like behaviours in rats.     

Graft-host tolerance in bone marrow transplant chimeras. Absence of graft-versus-host disease is associated with unresponsiveness to minor histocompatibility antigens expressed by all tissues

Because bone marrow (BM) transplantation is used with increasing frequency, it is important to elucidate the mechanisms involved in the establishment of tolerance to host minor histocompatibility antigens (MiHA) in recipients transplanted with T-cell-undepleted marrow grafts. We have previously shown that BM chimeras transplanted across MiHA barriers showed specific unresponsiveness to MiHA expressed on recipient-type concanavalin A blasts. Because expression of many MiHA is tissue-specific, we wanted to determine if chimera T lymphocytes would be tolerant to MiHA expressed by all host tissues and organs. To investigate this issue, we measured in vivo proliferation of lymphoid cells from normal C57BL/10 (B10) mice and (B10-->LP) chimeras in tissues and organs of lethally irradiated syngeneic and allogeneic recipients. Donor B10 cells were either untreated, or depleted with anti-Thy-1.2, anti-CD4, or anti-CD8 antibodies. Transplantation of B10 cells in LP recipients triggered an important T-cell-dependent 125I- dUrd uptake in several organs that involved both CD4+ and CD8+ cells. Using Thy-1-congeneic mice we showed that in long-term chimeras practically all CD4+ and CD8+ T lymphocytes were derived from hematopoietic progenitors and not from mature T cells present in the BM graft. When (B10-->LP) BM chimera cells were injected to secondary recipients, no proliferation was observed in any organ of LP hosts whereas normal proliferation was seen in H-2k allogeneic hosts. Thus, in these BM chimeras, tolerance encompasses MiHA expressed by all organs.     

Addressing health disparities in the Food and Drug Administration’s artificial intelligence and machine learning regulatory framework

The exponential growth of health data from devices, health applications, and electronic health records coupled with the development of data analysis tools such as machine learning offer opportunities to leverage these data to mitigate health disparities. However, these tools have also been shown to exacerbate inequities faced by marginalized groups. Focusing on health disparities should be part of good machine learning practice and regulatory oversight of software as medical devices. Using the Food and Drug Administration (FDA)''s proposed framework for regulating machine learning tools in medicine, I show that addressing health disparities during the premarket and postmarket stages of review can help anticipate and mitigate group harms.