The effect of stress on the expression of the amyloid precursor protein in rat brain

AbstractThe abnormal processing of the amyloid precursor protein (APP) is a pivotal event in the development of the unique pathology that defines Alzheimer's disease (AD). Stress, and the associated increase in corticosteroids, appear to accelerate brain ageing and may increase vulnerability to Alzheimer's disease via altered APP processing. In this study, rats were repeatedly exposed to an unavoidable stressor, an open elevated platform. Previous studies in this laboratory have shown that a single exposure produces a marked increase in plasma corticosterone levels but animals develop tolerance to this effect between 10 and 20 daily sessions. Twenty-four hours after stress, there was an increase in the ratio of the deglycosylated form of APP in the particulate fraction of the brain, which subsequently habituated after 20 days. The levels of soluble APP (APPs) tended to be lower in the stress groups compared to controls except for a significant increase in the hippocampus after 20 days of platform exposure. Since APPs is reported to have neurotrophic properties, this increased release may represent a neuroprotective response to repeated stress. It is possible that the ability to mount this response decreases with age thus increasing the vulnerability to stress-induced AD-related pathology

Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

Background: Many patients with COVID-19 have been treated with plasma containing anti-SARS-CoV-2 antibodies. We aimed to evaluate the safety and efficacy of convalescent plasma therapy in patients admitted to hospital with COVID-19. Methods: This randomised, controlled, open-label, platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]) is assessing several possible treatments in patients hospitalised with COVID-19 in the UK. The trial is underway at 177 NHS hospitals from across the UK. Eligible and consenting patients were randomly assigned (1:1) to receive either usual care alone (usual care group) or usual care plus high-titre convalescent plasma (convalescent plasma group). The primary outcome was 28-day mortality, analysed on an intention-to-treat basis. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936. Findings: Between May 28, 2020, and Jan 15, 2021, 11558 (71%) of 16287 patients enrolled in RECOVERY were eligible to receive convalescent plasma and were assigned to either the convalescent plasma group or the usual care group. There was no significant difference in 28-day mortality between the two groups: 1399 (24%) of 5795 patients in the convalescent plasma group and 1408 (24%) of 5763 patients in the usual care group died within 28 days (rate ratio 1·00, 95% CI 0·93–1·07; p=0·95). The 28-day mortality rate ratio was similar in all prespecified subgroups of patients, including in those patients without detectable SARS-CoV-2 antibodies at randomisation. Allocation to convalescent plasma had no significant effect on the proportion of patients discharged from hospital within 28 days (3832 [66%] patients in the convalescent plasma group vs 3822 [66%] patients in the usual care group; rate ratio 0·99, 95% CI 0·94–1·03; p=0·57). Among those not on invasive mechanical ventilation at randomisation, there was no significant difference in the proportion of patients meeting the composite endpoint of progression to invasive mechanical ventilation or death (1568 [29%] of 5493 patients in the convalescent plasma group vs 1568 [29%] of 5448 patients in the usual care group; rate ratio 0·99, 95% CI 0·93–1·05; p=0·79). Interpretation: In patients hospitalised with COVID-19, high-titre convalescent plasma did not improve survival or other prespecified clinical outcomes. Funding: UK Research and Innovation (Medical Research Council) and National Institute of Health Research

Tocilizumab in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Background: In this study, we aimed to evaluate the effects of tocilizumab in adult patients admitted to hospital with COVID-19 with both hypoxia and systemic inflammation. Methods: This randomised, controlled, open-label, platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing several possible treatments in patients hospitalised with COVID-19 in the UK. Those trial participants with hypoxia (oxygen saturation <92% on air or requiring oxygen therapy) and evidence of systemic inflammation (C-reactive protein ≥75 mg/L) were eligible for random assignment in a 1:1 ratio to usual standard of care alone versus usual standard of care plus tocilizumab at a dose of 400 mg–800 mg (depending on weight) given intravenously. A second dose could be given 12–24 h later if the patient's condition had not improved. The primary outcome was 28-day mortality, assessed in the intention-to-treat population. The trial is registered with ISRCTN (50189673) and ClinicalTrials.gov (NCT04381936). Findings: Between April 23, 2020, and Jan 24, 2021, 4116 adults of 21 550 patients enrolled into the RECOVERY trial were included in the assessment of tocilizumab, including 3385 (82%) patients receiving systemic corticosteroids. Overall, 621 (31%) of the 2022 patients allocated tocilizumab and 729 (35%) of the 2094 patients allocated to usual care died within 28 days (rate ratio 0·85; 95% CI 0·76–0·94; p=0·0028). Consistent results were seen in all prespecified subgroups of patients, including those receiving systemic corticosteroids. Patients allocated to tocilizumab were more likely to be discharged from hospital within 28 days (57% vs 50%; rate ratio 1·22; 1·12–1·33; p<0·0001). Among those not receiving invasive mechanical ventilation at baseline, patients allocated tocilizumab were less likely to reach the composite endpoint of invasive mechanical ventilation or death (35% vs 42%; risk ratio 0·84; 95% CI 0·77–0·92; p<0·0001). Interpretation: In hospitalised COVID-19 patients with hypoxia and systemic inflammation, tocilizumab improved survival and other clinical outcomes. These benefits were seen regardless of the amount of respiratory support and were additional to the benefits of systemic corticosteroids. Funding: UK Research and Innovation (Medical Research Council) and National Institute of Health Research

International Union Of Pharmacology. Xx. Current Status Of The Nomenclature For Nicotinic Acetylcholine Receptors And Their Subunits

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Prazosin attenuates the natriuretic response to atrial natriuretic factor in man

Prazosin attenuates the natriuretic response to atrial natriuretic factor in man. The effect of alpha-1-adrenoceptor blockade with 0.25mg oral prazosin on the renal response to atrial natriuretic factor (ANF) 5 pmol/kg/min was examined in eight healthy male volunteers undergoing maximal water diuresis. ANF on its own decreased mean arterial blood pressure (P < 0.05) without altering heart rate or increasing plasma norepinephrine. ANF increased urinary sodium excretion by 130% (P < 0.01) from baseline value with accompanying 18% decrease (P < 0.05) in PAH clearance (ERPF) without changing inulin clearance (GFR). When compared to placebo infusion, ANF infusion caused a significant increase in fractional excretion lithium (FELi), a marker of proximal tubular function. Fractional distal delivery of sodium, another marker of proximal tubular outflow as determined by free water clearance, was also increased during ANF infusion. As expected, ANF decreased distal nephron fractional sodium reabsorption as evaluated by both the “lithium method” and by the conventional “solute-free water method”. Prazosin on its own had no effect on blood pressure, renal function or hormonal parameters. When given in combination with ANF, prazosin blunted the natriuretic effect of ANF from 130% to 35% (P < 0.01). However, prazosin pretreatment did not influence the ANF-induced fall in blood pressure or ERPF nor the ANF-induced suppression of plasma aldosterone. We have therefore found evidence to support the hypothesis that at basal levels of sympathetic tone, the natriuretic effect of ANF in man is dependent on an intact sympathetic nervous system, since sympathetic blockade by prazosin blunts its sodium excretory effects

Historical and current perspective on tobacco use and nicotine addiction

Although the addictive influence of tobacco was recognized very early, the modern concepts of nicotine addiction have relied on knowledge of cholinergic neurotransmission and nicotinic acetylcholine receptors (nAChRs). The discovery of the “receptive substance” by Langley, that would turn out to be nAChRs, and “Vagusstoff” (acetylcholine) by Loewi, coincided with an exciting time when the concept of chemical synaptic transmission was being formulated. More recently, the application of more powerful techniques and the study of animal models that replicate key features of nicotine dependence have led to important advancements in our understanding of molecular, cellular, and systems mechanisms of nicotine addiction. In this Review, we present a historical perspective and overview of the research that has led to our present understanding of nicotine addiction

Cytomegalovirus and other herpesviruses infections in heart and bone marrow transplant recipients Infecções causadas por citomegalovírus e outros vírus do grupo herpes em transplantados cardíacos e de medula óssea

From January 1988 to January 1989 all the heart transplant and bone marrow recipients at the Instituto do Coração of the Hospital das Clínicas of the University of São Paulo Medical School were studied for the incidence and morbidity associated with herpesviruses infections after transplantation. Five bone marrow and 5 heart transplant recipients were followed for a mean of 4.2 months post-transplantation. All the patients were seropositive for cytomegalovirus (CMV) before admission and 80% experienced one or more recurrences during the observation period. Of the 12 episodes of CMV infection, that were identified in this study, 83% were accompanied by clinical or laboratory abnormalities. However, there was only one case of severe disease. The overall incidence of infection for herpes simplex (HSV) was 50%. Although most of HSV reactivations were oral or genital, one case of HSV hepatitis occurred. One of the 6 episodes of HSV infections that were treated with acyclovir showed an unsatisfactory response and was successfully managed with ganciclovir. All the individuals had anti-varicella zoster virus antibodies, but none of them developed infection. The study emphasizes the importance of active diagnostic surveillance of herpesvirus infections in transplant patients. Both CMV and HSV reactivations showed high incidence and important morbidity and thus, deserve prophylactic therapy.<br>De janeiro de 1988 a janeiro de 1989 todos os pacientes submetidos a transplante de coração ou de medula óssea no Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo foram estudados quanto à incidência e morbidade das infecções pós-transplante causadas por vírus do grupo herpes. Cinco recipientes de medula óssea e 5 transplantados cardíacos foram observados por um período médio de 4.2 meses após o transplante. Todos os pacientes tinham sorologia positiva para citomegalovírus (CMV) antes do transplante e 80% desenvolveram uma ou mais recorrências durante o período de observação. Dos 12 episódios de infecão por CMV detectados neste estudo, 83% foram acompanhados por alterações clínicas ou laboratoriais. Apenas um caso apresentou doença grave. A incidência de infecções causadas por vírus Herpes simplex (HSV), foi de 50%. Apesar da maioria das reativações do HSV fossem representadas por lesões orais ou genitais, houve também um caso de hepatite por HSV. Um dos 6 episódios de infecção, por HSV que foram tratados com aciclovir não respondeu ao tratamento. Posteriormente, o paciente se beneficiou com o uso de ganciclovir. Todos os indivíduos apresentavam antes do transplante anticorpos anti-vírus da varicela zoster. Porém, não houve nenhum caso de reativação. Este estudo realça a importância do controle diagnóstico ativo das infecções por herpes-vírus em pacientes transplantados. Tanto as infecções causadas por CMV como por HSV mostraram alta incidência e grande morbidade indicando a necessidade de quimioprofilaxia