1. Our aim was to determine whether the vasodilating substance nitric oxide (NO) contributes to the rise in forearm blood flow observed during mental stress in humans. We also determined whether the NO might be released as a result of cholinergic stimulation of the vascular endothelium. 2. Blood flow was measured in both forearms using plethysmography during several 3‐5 min bouts of a colour word test. In one forearm the nitric oxide synthase blocker NG‐monomethyl‐L‐arginine (L‐NMMA) and other drugs were infused via a brachial artery catheter. The contralateral forearm served as a control. 3. When L‐NMMA was given prior to mental stress it blunted the rise in blood flow in the treated forearm almost completely. The normal blood flow response returned during a second bout of stress conducted after a wash‐out period. During a third bout of mental stress, administration of more L‐NMMA again blunted the blood flow responses to mental stress. 4. When atropine was given prior to mental stress, the increases in blood flow were reduced in the treated forearm. Subsequent administration of both atropine and L‐NMMA caused a somewhat greater reduction in the blood flow responses than those observed with atropine alone. 5. These data demonstrate that NO plays a role in forearm vasodilatation during mental stress in humans. It is likely that most of the NO is released by cholinergic stimulation of the vascular endothelium.

All methods were sensitive to variation in both the rate of EE and the duration over which activity was monitored. Accelerometry and PAR are useful methods for categorizing EE in epidemiologic studies among pregnant women but absolute estimates are biased relative to HR.

A woman's HR, VO2, and the relationship between these two parameters are altered during pregnancy. Change in slope of HR/VO2 regression curves indicates less energy expenditure at a given HR as pregnancy progresses, compared with postpartum conditions. A woman's true energy expenditure would be overestimated at rest, and underestimated during physical activity, if these physiological changes are not taken into account.

No abstract

We describe a 61-year-old woman with "broken heart syndrome" (Takotsubo-like cardiomyopathy) after abrupt postsurgical withdrawal of OxyContin. Her medical history was remarkable for long-term opiold dependence associated with the treatment of multi-Joint degenerative osteoarthritis. The patient presented to the emergency department 1 day after discharge from the hospital following total knee arthroplasty revision with acute-onset dyspnea and mild chest pain. She had precordial ST-segment elevation characteristic of acute myocardial infarction and elevated cardiac biomarkers. Emergency coronary angiography revealed no major coronary atherosclerosis. However, the left ventricular ejection fraction was severely decreased (26%), and new regional wall motion abnormalities typical of broken heart syndrome were noted. In addition to resuming her opioid therapy, she was treated supportively with bilevel positive airway pressure, diuretic therapy, morphine, aspirin, metoprolol, enalaprilat, intravenous heparin, nitroglycerin infusion, and dopamine infusion. Ventricular systolic function recovered completely by the fourth hospital day. To our knowledge, broken heart syndrome after opioid withdrawal has not been reported previously in an adult. Our case illustrates the importance of continuing adequate opiate therapy perioperatively in the increasing number of opioid-dependent patients to prevent potentially life-threatening complications such as broken heart syndrome.

Bioartificial liver increases survival and allows spontaneous recovery in pigs with fulminant hepatic failure.

Evidence shows that chronic diseases are associated with COVID-19 severity and death. This study aims to estimate the fraction of hospitalizations and deaths from COVID-19 attributable to chronic diseases associated to poor nutrition and smoking among adults who tested positive to COVID-19 in Mexico. We analyzed 1,006,541 adults aged ≥20 who tested positive for COVID-19 from March 23 to December 5, 2020. Six chronic diseases were considered: obesity, chronic obstructive pulmonary disease (COPD), hypertension, diabetes, cardiovascular disease, and chronic kidney disease (CKD). We calibrated the database using a bias quantification method to consider undiagnosed disease cases. To estimate the total impact of multiple diseases, we defined a multimorbidity variable according to the number of diseases. Risks of hospitalization and death were estimated with Poisson regression models and used to calculate population attributable fractions (PAFs). Chronic diseases accounted for to 25.4% [95% CI: 24.8%–26.1%], 28.3% (95% CI: 27.8%–28.7%) and 15.3% (95% CI: 14.9%–15.7%) of the hospitalizations among adults below 40, 40–59, and 60 years and older, respectively. For COVID-19-related deaths, 50.1% (95% CI: 48.6%–51.5%), 40.5% (95% CI: 39.7%–41.3%), and 18.7% (95% CI, 18.0%–19.5%) were attributable to chronic diseases in adults under 40, 40–59, and 60 years and older, respectively. Chronic diseases linked to poor nutrition and smoking could have contributed to a large burden of hospitalization and deaths from COVID-19 in Mexico, particularly among younger adults. Medical and structural interventions to curb chronic disease incidence and facilitate disease control are urgently needed.

Background Estimates of SARS-CoV-2 infection fatality rates (IFRs) in developing countries remain poorly characterized. Mexico has one of the highest reported COVID-19 case-fatality rates worldwide, although available estimates do not consider serologic assessment of prior exposure nor all SARS-CoV-2-related deaths. We aimed to estimate sex- and age-specific IFRs for SARS-CoV-2 in Mexico. Methods The total number of people in Mexico with evidence of prior SARS-CoV-2 infection was derived from National Survey of Health and Nutrition-COVID-19 (ENSANUT 2020 Covid-19)—a nationally representative serosurvey conducted from August to November 2020. COVID-19 mortality data matched to ENSANUT’s dates were retrieved from the death-certificate registry, which captures the majority of COVID-19 deaths in Mexico, and from the national surveillance system, which covers the subset of COVID-19 deaths that were identified by the health system and were confirmed through a positive polymerase chain reaction test. We analysed differences in IFRs by urbanization and region. Results The national SARS-CoV-2 IFR was 0.47% (95% CI 0.44, 0.50) using death certificates and 0.30% (95% CI 0.28, 0.33) using surveillance-based deaths. The IFR increased with age, being close to zero at age <30 years, but increasing to 1% at ages 50–59 years in men and 60–69 years in women, and being the highest at ≥80 years for men (5.88%) and women (6.23%). Across Mexico's nine regions, Mexico City (0.99%) had the highest and the Peninsula (0.26%) the lowest certificate-based IFRs. Metropolitan areas had higher certificate-based IFR (0.63%) than rural areas (0.17%). Conclusion After the first wave of the COVID-19 pandemic, the overall IFR in Mexico was comparable with those of European countries. The IFR in Mexico increased with age and was higher in men than in women. The variations in IFRs across regions and places of residence within the country suggest that structural factors related to population characteristics, pandemic containment and healthcare capabilities could have influenced lethality at the local level.