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Toxoplasma gondii infects humans and warm blooded animals causing devastating disease worldwide. It has long been a mystery as to why the peritoneal macrophages of rats are naturally resistant to T. gondii infection while those of mice are not. Here, we report that high expression levels and activity of inducible nitric oxide synthase (iNOS) and low levels of arginase-1 (Arg 1) activity in the peritoneal macrophages of rats are responsible for their resistance against T. gondii infection, due to high nitric oxide and low polyamines within these cells. The opposite situation was observed in the peritoneal macrophages of mice. This discovery of the opposing functions of iNOS and Arg 1 in rodent peritoneal macrophages may lead to a better understanding of the resistance mechanisms of mammals, particularly humans and livestock, against T. gondii and other intracellular pathogens.

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SUMMARYThe limits to sustained energy intake (SusEI) are important because they determine the ceiling restricting all the competing physiological processes. A recent hypothesis is that SusEI is constrained by the capacity to dissipate heat. However some previous data for Swiss mice are inconsistent with this hypothesis. To examine the role of limits to heat dissipation on SusEI, the body temperature, thermal conductance and lactation performance were measured in dorsally shaved Swiss mice. Shaving reduces external insulation and the heat dissipation limitation hypothesis predicts such animals should be capable of eating more food and raising heavier litters. Shaved mice had a significantly higher thermal conductance and a faster reduction in body temperature following noradrenaline injection. At peak lactation, shaved mice spent more time in feeding behaviour, and increased food intake above that observed in non-shaved controls, indicating that limits on SusEI might be imposed by the capacity to dissipate heat. However, shaved females did not spend more time suckling their pups, and did not raise heavier litters, which is inconsistent with the expectations of the heat dissipation limitation hypothesis. The strong correlations between resting, feeding and suckling behaviour at peak lactation suggested that there might be a trade-off in the time distribution between the behavioural patterns. These data suggest that limits on performance may be set at different levels in different strains or species. In MF1 mice studied previously the limit on milk production imposed by maximal mammary secretion capability may lie above that for heat dissipation, hence when the latter was increased the mice produced more milk and raised heavier litters. In Swiss mice the opposite might be the case. Hence when the heat dissipation capacity was increased this did not translate into heavier litters, i.e. supporting the peripheral limitation hypothesis. Further work in a range of additional species or strains will be necessary to establish whether the more normal condition is for SusEI in animals during late lactation to be set by combined peripheral demands or by the heat dissipation capacity.

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Toxoplasmosis, caused by the protozoan parasite Toxoplasma gondii, is one of the most common parasitic infections in humans. Primary infection in pregnant women can be transmitted to the fetus leading to miscarriage or congenital toxoplasmosis. Carefully designed nationwide seroprevalence surveys and case-control studies of risk factors conducted primarily in Europe and America, have shaped our view of the global status of maternal and congenital infection, directing approaches to disease prevention. However, despite encompassing 1 in 5 of the world's population, information is limited on the status of toxoplasmosis in China, partly due to the linguistic inaccessibility of the Chinese literature to the global scientific community. By selection and analysis of studies and data, reported within the last 2 decades in China, this review summarizes and renders accessible a large body of Chinese and other literature and aims to estimate the seroprevalence in Chinese pregnant women. It also reviews the prevalence trends, risk factors, and clinical manifestations. The key findings are (1) the majority of studies show that the overall seroprevalence in Chinese pregnant women is less than 10%, considerably lower than a recently published global analysis; and (2) the few available appropriate studies on maternal acute infection suggested an incidence of 0·3% which is broadly comparable to studies from other countries.

Diabetic nephropathy is one of the most prevalent chronic complications of Diabetes mellitus, but its pathogenesis remains elusive. This study was designed to determine the role of tristetraprolin (TTP), inflammatory cytokines and microRNAs (miRNAs) in DN. The blood and urine samples were obtained from 32 patients with DN, 33 patients with type 2 DM, and 35 normal healthy subjects as controls. Renal tissue samples were also obtained from 10 DN patients and 10 normal controls. The miRNA microarray analyses were performed in pooled plasma and urine sediment samples of eight DN patients and eight age- and sex-matched health control subjects and three paired renal tissues from patients with DN and normal controls. Conditionally immortalized mouse podocytes (MPC5) were used a cell model. The expressions of TTP and cytokines in patient samples and cultured cells were determined by qRT-PCR and Western blotting or ELISA. Our results indicated that miRNA-29c directly targeted TTP and promoted inflammatory response under hyperglycemic conditions. Overexpression of miRNA-29c in podocytes resulted in an increase in inflammatory cytokines and inhibition of miRNA-29c by using its inhibitor reduced the inflammatory cytokines in podocytes. Finally, miRNA-29c promoted the progression of DN by targeting TTP, providing a target for a therapeutic intervention of DN.

The outbreak of the novel coronavirus SARS-CoV-2 (causing coronavirus disease-2019; COVID-19) has spread to most countries in the world. COVID-19 infection results in diverse clinical outcomes, ranging from no symptoms to critically severe pneumonia with extrapulmonary manifestations (Guan et al., 2020; Huang et al., 2020). Lipids play numerous indispensable functions in lung biology and the pathophysiology of viral infection. Pulmonary surfactant is over 90% lipids and 10% protein by weight (Han & Mallampalli, 2015).