The Genetic Control of Two Lethal Traits in Variety 1, Tetrahymena pyriformis *

A breeding analysis of a wild strain (Indian Lake 12) of variety 1, Tetrahymena pyriformis , discloses recessive lethal alleles at two independently assorting loci. Conclusions concerning the cytogenetic behavior of this species have been verified through the scoring of a large number of offspring segregating the lethals. In particular, cytogamy does not occur in these strains with a frequency higher than 2%. if indeed it occurs at all. The finding of lethal heterozygosity in a wild strain suggests that close inbreeding usually does not take place in nature and supports the conclusion that variety 1 of T. pyriformis is an outbreeding species.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73131/1/j.1550-7408.1960.tb00710.x.pd

Gender Different Response to Immunonutrition in Liver Cirrhosis with Sepsis in Rats

Females with sepsis have a better prognosis than males, while those of both genders with cirrhosis have a high mortality. Impaired immunity accompanies liver cirrhosis. The potential association between sex and immunologic response of cirrhotic rats in sepsis following immunonutrition was investigated. One hundred and forty-three rats were randomly divided into groups. Liver cirrhosis was produced by weekly feeding of CCl4 for 8 weeks. Among them, 24 male and 19 female underwent castration one month before studying. The rats were fed with either immune enhancing diet or control diet for five days, then sepsis was induced with cecal ligation and two holes puncture. Main outcomes included mortality and serum cytokines (IL-1β, 6, and 10). Comparisons were made both within and between genders. Cirrhotic non-castrated male rats showed a significant decrease in mortality (64.1% vs. 32.1%, p = 0.032) with better survival than control diet following immune enhancing diet. Lower mortality of cirrhotic non-castrated female rats was found after immune enhancing diet (69.6% vs. 52.1%, p = 0.365). Cirrhotic castrated male rats showed a lower mortality (44.4%) following immune enhancing diet, and cirrhotic castrated female rats also showed significantly lower mortality and better survival than control diet after immune enhancing diet (87.5% vs. 33.3%, p = 0.004). Plasma concentrations of IL-1β were higher in non-oophorectomized female rats fed with control diet compared to immune enhancing diet. Non-orchidectomized males and non-oophorectomized females exhibited similar increases in IL-10 after immune enhancing diet. Our results demonstrated that immunonutrition was more beneficial for male than female cirrhotic rats following sepsis. Though orchidectomy was not found to be more advantageous for the normal male rats in sepsis, immunonutrition seemed to be as important as sex hormone for female rats in sepsis

Pivotal Role of the α2A-Adrenoceptor in Producing Inflammation and Organ Injury in a Rat Model of Sepsis

Background: Norepinephrine (NE) modulates the responsiveness of macrophages to proinflammatory stimuli through the activation of adrenergic receptors (ARs). Being part of the stress response, early increases of NE in sepsis sustain adverse systemic inflammatory responses. The intestine is an important source of NE release in the early stage of cecal ligation and puncture (CLP)-induced sepsis in rats, which then stimulates TNF-a production in Kupffer cells (KCs) through the activation of the a2-AR. It is important to know which of the three a2-AR subtypes (i.e., a2A, a2B or a2C) is responsible for the upregulation of TNF-a production. The aim of this study was to determine the contribution of a2A-AR in this process. Methodology/Principal Findings: Adult male rats underwent CLP and KCs were isolated 2 h later. Gene expression of a2A-AR was determined. In additional experiments, cultured KCs were incubated with NE with or without BRL-44408 maleate, a specific a2A-AR antagonist, and intraportal infusion of NE for 2 h with or without BRL-44408 maleate was carried out in normal animals. Finally, the impact of a2A-AR activation by NE was investigated under inflammatory conditions (i.e., endotoxemia and CLP). Gene expression of the a2A-AR subtype was significantly upregulated after CLP. NE increased the release of TNF-a in cultured KCs, which was specifically inhibited by the a2A-AR antagonist BRL-44408. Equally, intraportal NE infusion increased TNF-a gene expression in KCs and plasma TNF-a which was also abrogated by co-administration of BRL-44408. NE also potentiated LPS-induced TNF-a release via the a2A-AR in vitro and in vivo. This potentiation of TNF-a release by NE was mediated through the a2A-AR coupled Gai protein and the activation of the p38 MAP kinase. Treatment of septic animals with BRL-44408 suppressed TNF-a, prevented multiple organ injury and significantly improved survival from 45% to 75%. Conclusions/Significance: Our novel finding is that hyperresponsiveness to a2-AR stimulation observed in sepsis is primarily due to an increase in a2A-AR expression in KCs. This appears to be in part responsible for the increased proinflammatory response and ensuing organ injury in sepsis. These findings provide important feasibility information for further developing the a2A-AR antagonist as a new therapy for sepsis

Baicalin Improves Survival in a Murine Model of Polymicrobial Sepsis via Suppressing Inflammatory Response and Lymphocyte Apoptosis

BACKGROUND: An imbalance between overwhelming inflammation and lymphocyte apoptosis is the main cause of high mortality in patients with sepsis. Baicalin, the main active ingredient of the Scutellaria root, exerts anti-inflammatory, anti-apoptotic, and even antibacterial properties in inflammatory and infectious diseases. However, the therapeutic effect of baicalin on polymicrobial sepsis remains unknown. METHODOLOGY/PRINCIPAL FINDINGS: Polymicrobial sepsis was induced by cecal ligation and puncture (CLP) in C57BL/6 mice. Mice were infused with baicalin intraperitoneally at 1 h, 6 h and 12 h after CLP. Survival rates were assessed over the subsequent 8 days. Bacterial burdens in blood and peritoneal cavity were calculated to assess the bacterial clearance. Neutrophil count in peritoneal lavage fluid was also calculated. Injuries to the lung and liver were detected by hematoxylin and eosin staining. Levels of cytokines, including tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-10 and IL-17, in blood and peritoneum were measured by enzyme-linked immunosorbent assay. Adaptive immune function was assessed by apoptosis of lymphocytes in the thymus and counts of different cell types in the spleen. Baicalin significantly enhanced bacterial clearance and improved survival of septic mice. The number of neutrophils in peritoneal lavage fluid was reduced by baicalin. Less neutrophil infiltration of the lung and liver in baicalin-treated mice was associated with attenuated injuries to these organs. Baicalin significantly reduced the levels of proinflammatory cytokines but increased the level of anti-inflammatory cytokine in blood and peritoneum. Apoptosis of CD3(+) T cell was inhibited in the thymus. The numbers of CD4(+), CD8(+) T lymphocytes and dendritic cells (DCs) were higher, while the number of CD4(+)CD25(+) regulatory T cells was lower in the baicalin group compared with the CLP group. CONCLUSIONS/SIGNIFICANCE: Baicalin improves survival of mice with polymicrobial sepsis, and this may be attributed to its antibacterial property as well as its anti-inflammatory and anti-apoptotic effects

Protection of early phase hepatic ischemia-reperfusion injury by cholinergic agonists

BACKGROUND: Cytokine production is critical in ischemia/reperfusion (IR) injury. Acetylcholine binds to macrophages and inhibits cytokine synthesis, through the cholinergic anti-inflammatory pathway. This study examined the role of the cholinergic pathway in cytokine production and hepatic IR- injury. METHODS: Adult male mice underwent 90-min of partial liver ischemia followed by reperfusion. The AChR agonists (1,1-dimethyl-4-phenyl-L-pioperazinium-iodide [DMPP], and nicotine) or saline-vehicle were administered i.p. before ischemia. Plasma cytokine tumor necrosis factor (TNF)-α, macrophage inflammatory protein-2, and Interleukin-6 were measured. Liver injury was assessed by plasma alanine transaminase (ALT) and liver histopathology. RESULTS: A reperfusion time-dependent hepatocellular injury occurred as was indicated by increased plasma-ALT and histopathology. The injury was associated with marked elevation of plasma cytokines/chemokines. Pre-ischemic treatment of mice with DMPP or nicotine significantly decreased plasma-ALT and cytokines after 3 h of reperfusion. After 6 h of reperfusion, the protective effect of DMPP decreased and reached a negligible level by 24 h of reperfusion, despite significantly low levels of plasma cytokines. Histopathology showed markedly diminished hepatocellular injury in DMPP- and nicotine-pretreated mice during the early-phase of hepatic-IR, which reached a level comparable to saline-treated mice at late-phase of IR. CONCLUSION: Pharmacological modulation of the cholinergic pathway provides a means to modulate cytokine production and to delay IR-induced heaptocellular injury

Outer Membrane Vesicles Derived from Escherichia coli Induce Systemic Inflammatory Response Syndrome

Sepsis, characterized by a systemic inflammatory state that is usually related to Gram-negative bacterial infection, is a leading cause of death worldwide. Although the annual incidence of sepsis is still rising, the exact cause of Gram-negative bacteria-associated sepsis is not clear. Outer membrane vesicles (OMVs), constitutively secreted from Gram-negative bacteria, are nano-sized spherical bilayered proteolipids. Using a mouse model, we showed that intraperitoneal injection of OMVs derived from intestinal Escherichia coli induced lethality. Furthermore, OMVs induced host responses which resemble a clinically relevant condition like sepsis that was characterized by piloerection, eye exudates, hypothermia, tachypnea, leukopenia, disseminated intravascular coagulation, dysfunction of the lungs, hypotension, and systemic induction of tumor necrosis factor-α and interleukin-6. Our study revealed a previously unidentified causative microbial signal in the pathogenesis of sepsis, suggesting OMVs as a new therapeutic target to prevent and/or treat severe sepsis caused by Gram-negative bacterial infection