The role of protein synthesis in adrenocorticotrophin action: Effects of cycloheximide and puromycin on the steroidogenic response of isolated adrenocortical cells

The kinetics of the corticosteroidogenic response to adrenocorticotrophin (ACTH) have been investigated using collagenase dispersed adrenocortical cells. Following the addition of ACTH at a concentration that was maximal for steroidogenesis, there was a time-lag of about 3 min before increased steroidogenesis became apparent. This lag was extended (about two-fold) in the presence of a half-maximal concentration of ACTH. Preincubation of cells with submaximal concentrations of both cycloheximide and puromycin extended the time-lag observed following ACTH addition. Increasing doses of cycloheximide or puromycin concomitantly inhibited protein synthesis and steroidogenesis. Moreover cycloheximide, at a dose that halved protein synthesis, also inhibited steroidogenesis by 54–61% for a range of ACTH concentrations (1 × 10⁻⁴ to 1 × 10⁻² I.U./ml).It is concluded that the delay before ACTH-stimulated steroidogenesis is not attributable solely to the time taken for ribosomes to read of from the mRNA strand, the code for protein regulator(s). The results are discussed in terms of steroidogenic mechanisms whereby ACTH either induces de novo protein synthesis or activates a pre-existing, but labile, protein. In this latter scheme the steroidogenic rate observed under various conditions would be directly dependent upon the intracellular level of such an activated protein regulator. The half-life of labile protein, implicated as regulating steroidogenesis, was estimated at 2–4 min in this adrenal cell suspension system.     

HIV-related enteropathy in Zambia: a clinical, microbiological, and histological study

To investigate the etiology of chronic diarrhea associated with human immunodeficiency virus (HIV) infection in Lusaka, we studied 63 HIV-positive patients and 36 seronegative controls clinically and endoscopically. Stools were studied for morphology and for opportunist infections. Fifty-five percent of patients seropositive for HIV who presented with a history of chronic diarrhea had parasites; the most common were Cryptosporidium (32%), Isospora belli (16%), and Strongyloides stercoralis (6%). As indicated by villous blunting and inflammation on duodenal histology, those with diarrhea and parasites showed the most severe damage. We could not implicate mycobacteria or bacterial overgrowth as causes for the enteropathy associated with HIV.     

Pneumocystis carinii pneumonia. An uncommon cause of death in African patients with acquired immunodeficiency syndrome.

Admissions and deaths in a pulmonary medicine ward in Abidjan, Cote d'Ivoire, West Africa, were evaluated over a 6-month period in 1989 with systematic autopsies on all patients who died. Of 473 patients admitted, 38% were HIV-1 seropositive, 4% were HIV-2 seropositive, and 14% reacted to both viruses. A total of 100 patients (21%) died, and deaths were twice as frequent in HIV-seropositive compared with HIV-negative patients. The pathology of 78 autopsies showed that the predominant cause of death in HIV-seropositive patients was disseminated tuberculosis (40%). Cancer was the cause of death in 64% of HIV-negative patients. Pneumocystosis was found in only 9% of HIV-seropositive autopsies. Since Pneumocystis carinii is an uncommon cause of death in this population, prophylaxis for P. carinii pneumonia is not warranted for HIV-infected patients in Africa. In contrast, research on chemoprophylaxis for tuberculosis is urgently required.     

Gastric emptying before and after cholecystectomy in patients with cholecystolithiasis

BACKGROUND/AIMS: The objective of the present study was to measure gastric emptying time of solids and semisolids in dyspeptic individuals with cholecystolithiasis before and 6 months after cholecystectomy in order to determine whether cholecystectomy interferes with gastric emptying. METHODOLOGY: A prospective, self-pairing study was conducted on 29 patients selected according to appropriate inclusion and exclusion criteria. Gastric emptying time of solids and semisolids was determined before and six months after laparoscopic cholecystectomy by the 13C-octanoic acid and 13C-acetate breath tests, respectively. The samples were analyzed by infrared spectrometry. The gastric retention time (lag phase) and gastric emptying half-time of solid and semisolid were determined and the results obtained before and after surgery were compared in the same patient. In addition, the effects of surgery on dyspeptic symptoms were assessed. RESULTS: No significant differences (p>0.05) in gastric retention time and gastric emptying half-time of solid and semisolid test meals were observed before and after cholecystectomy. Dyspeptic symptoms (pain, upper abdominal gases, early satiety, nausea and vomiting) improved after surgery. CONCLUSIONS: Laparoscopic cholecystectomy does not interfere with the gastric emptying time of solids or semisolids in dyspeptic individuals with cholecystolithiasis.     

Complicaciones infecciosas en niños tratados con oxigenación por membrana extracorpórea

Introduction

The aim of this study was to analyse the incidence, treatment and evolution of infections in children treated with ECMO.

Oral administration of PEGylated TLR7 ligand ameliorates alcohol-associated liver disease via the induction of IL-22

Effective therapies for alcohol-associated liver disease (ALD) are limited; therefore, the discovery of new therapeutic agents is greatly warranted. Toll-like receptor 7 (TLR7) is a pattern recognition receptor for single-stranded RNA, and its activation prevents liver fibrosis. We examined liver and intestinal damage in Tlr7^−/− mice to determine the role of TLR7 in ALD pathogenesis. In an alcoholic hepatitis (AH) mouse model, hepatic steatosis, injury, and inflammation were induced by chronic binge ethanol feeding in mice, and Tlr7 deficiency exacerbated these effects. Because these results demonstrated that endogenous TLR7 signaling activation is protective in the AH mouse model, we hypothesized that TLR7 activation may be an effective therapeutic strategy for ALD. Therefore, we investigated the therapeutic effect of TLR7 agonistic agent, 1Z1, in the AH mouse model. Oral administration of 1Z1 was well tolerated and prevented intestinal barrier disruption and bacterial translocation, which thus suppressed ethanol-induced hepatic injury, steatosis, and inflammation. Furthermore, 1Z1 treatment up-regulated the expression of antimicrobial peptides, Reg3b and Reg3g, in the intestinal epithelium, which modulated the microbiome by decreasing and increasing the amount of Bacteroides and Lactobacillus, respectively. Additionally, 1Z1 up-regulated intestinal interleukin (IL)-22 expression. IL-22 deficiency abolished the protective effects of 1Z1 in ethanol-induced liver and intestinal damage, suggesting intestinal IL-22 as a crucial mediator for 1Z1-mediated protection in the AH mouse model. Collectively, our results indicate that TLR7 signaling exerts protective effects in the AH mouse model and that a TLR7 ligand, 1Z1, holds therapeutic potential for the treatment of AH.

Alcohol-associated liver disease (ALD) is caused by chronic and excessive consumption of alcohol. The disease ranges from alcohol-associated fatty liver to alcoholic hepatitis (AH), fibrosis, cirrhosis, and hepatocellular carcinoma (HCC) (1). Alcohol-associated fatty liver is considered reversible and nonprogressive. Nearly 35% of heavy alcohol drinkers develop AH, and up to 40% of severe AH patients die within 6 mo (2). AH patients who survive may progress to alcohol-associated cirrhosis. Treatment options for AH involve the use of corticosteroids and have remained largely unchanged since the early 1970s. Unfortunately, not all patients respond to corticosteroids, and the benefits are temporary in responders (1, 2). Early liver transplant has been shown to be superior to medical management for severe AH, but it still has limitations and can only be considered in a highly selective group of patients (1, 2). Thus, the identification of a better molecular therapeutic target for ALD is a significantly unmet medical need for the development of effective therapies for AH.Previous studies have demonstrated the involvement of Toll-like receptors (TLRs), including TLR2, TLR4, and TLR9, in the development of ALD (3–8). In addition to the direct effect of alcohol and its metabolite, acetaldehyde, in hepatocytes, ethanol intake affects the function of the intestinal epithelial barrier. Chronic alcohol consumption disrupts intestinal tight junction integrity and increases gut permeability, resulting in elevated bacterial lipopolysaccharide (LPS) concentrations in the portal and systemic circulation (4). Translocated LPS activates resident hepatic macrophages, known as Kupffer cells, via TLR4, thereby promoting ALD (1, 2, 7, 8). Other TLRs, such as TLR2 and TLR9, recognize gram-positive bacterial components and bacterial CpG-DNA, respectively (3, 4). Furthermore, TLR2, TLR9, and MyD88 are required for the development of the preclinical AH murine model (5), whereas TLR4 and TLR9 exert protective effects against intestinal inflammation (9, 10).TLR7 signaling has been shown to be protective against liver fibrosis in mice (11). Tlr7^−/− mice exhibit augmented cholestasis and carbon tetrachloride (CCl₄)-induced liver fibrosis (11). TLR7 signaling also induces IFN-α production in dendritic cells (DCs), followed by interleukin (IL)-1 receptor antagonist (IL-1Ra) induction in Kupffer cells. IL-1Ra suppresses IL-1-induced hepatic stellate cell (HSC) activation, resulting in inhibition of liver fibrosis (11). Among the TLRs, TLR3 and TLR7 activation has been reported to ameliorate some liver diseases (11, 12). However, a major disadvantage of the currently available synthetic ligands for TLR3 and TLR7, such as poly I:C, imiquimod, and R848, is the excessive induction of proinflammatory cytokines (3, 4). Thus, developing agents without undesirable adverse effects is of great clinical interest.IL-22 is a hepatoprotective cytokine produced by T helper (Th) 17 cells, Th22 cells, γδ T cells, natural killer (NK) T cells, and innate lymphoid cells (ILCs) (13). Exogenous administration of IL-22 has a profound effect on tissue repair following liver injury via the promotion of proliferation and inhibition of apoptosis in hepatocytes of mouse models of AH (14), liver fibrosis, and drug- and LPS-induced liver injury. Also, IL-22 promotes tissue repair in the intestines and is protective against intestinal epithelial damage and inflammation (13). These findings suggest that IL-22 may suppress ALD via the maintenance of intestinal barrier function, thereby preventing increased intestinal permeability and bacterial translocation due to intestine-derived microbial products that promote ethanol-induced liver injury (15, 16).Here, we have developed a synthetic TLR7 ligand, 1Z1, that possesses antiinflammatory effects via IL-22 induction and that is devoid of systemic toxicity after oral administration (17–19). Treatment with 1Z1 has already been reported to be effective for allergic encephalomyelitis, arthritis, dextran sodium sulfate (DSS)-induced colitis, and type I diabetes in mice (17–20). We hypothesize that targeting TLR7 activation may be an effective treatment strategy for ALD. Our experimental results demonstrate that 1Z1 oral administration inhibits ethanol-induced liver and intestinal damage and that these beneficial effects are due to intestinal IL-22 induction in an AH murine model.     

Decoding ultrafast polarization responses in lead halide perovskites by the two-dimensional optical Kerr effect

The ultrafast polarization response to incident light and ensuing exciton/carrier generation are essential to outstanding optoelectronic properties of lead halide perovskites (LHPs). A large number of mechanistic studies in the LHP field to date have focused on contributions to polarizability from organic cations and the highly polarizable inorganic lattice. For a comprehensive understanding of the ultrafast polarization response, we must additionally account for the nearly instantaneous hyperpolarizability response to the propagating light field itself. While light propagation is pivotal to optoelectronics and photonics, little is known about this in LHPs in the vicinity of the bandgap where stimulated emission, polariton condensation, superfluorescence, and photon recycling may take place. Here we develop two-dimensional optical Kerr effect (2D-OKE) spectroscopy to energetically dissect broadband light propagation and dispersive nonlinear polarization responses in LHPs. In contrast to earlier interpretations, the below-bandgap OKE responses in both hybrid CH₃NH₃PbBr₃ and all-inorganic CsPbBr₃ perovskites are found to originate from strong hyperpolarizability and highly anisotropic dispersions. In both materials, the nonlinear mixing of anisotropically propagating light fields results in convoluted oscillatory polarization dynamics. Based on a four-wave mixing model, we quantitatively derive dispersion anisotropies, reproduce 2D-OKE frequency correlations, and establish polarization-dressed light propagation in single-crystal LHPs. Moreover, our findings highlight the importance of distinguishing the often-neglected anisotropic light propagation from underlying coherent quasiparticle responses in various forms of ultrafast spectroscopy.

Understanding the ultrafast polarization response to light fields and the subsequent generation of charge carriers or excitons is key to establishing the photophysical mechanisms in the excellent optoelectronic material system of lead halide perovskites (LHPs) (1). The two ionic polarization contributions by the reorientational motion of organic cations and the deformation of the inorganic cages have been discussed within dynamic screening models (2–4) and large polaron formation (5), respectively and jointly, whereas the immediate electronic polarization response to the light field itself has been neglected so far. In many optoelectronic applications, nevertheless, not only charge carrier transport but also light propagation right below the bandgap is essential. In LHP nanowire lasers, the lasing modes are known to be redshifted from excitonic resonances due to efficient coupling to plasmon emission (6). In LHP-based exciton–polariton devices, light–matter coupling redshifts the hybrid state on the lower polariton branch (7). Propagation of subgap light is known to boost the efficiency of LHP photovoltaic cells and light-emitting devices by the so-called “photon recycling” (8). Light propagation strongly influences the function of LHP photonic devices in general (9, 10). A key feature of light propagation near the bandgap is its strong photon energy dependence, as is obvious from the classic Lorentzian model for the dielectric function near an optical resonance (11). However, most photophysical experiments probing carrier/exciton formation, screening, scattering, and nonlinear optical responses employ ultrashort excitation pulses with inherently broad energy distribution and thus convoluted spectral responses. Here, we develop a Fourier-transform-based laser spectroscopy technique, two-dimensional optical Kerr effect (2D-OKE), to investigate light propagation and nonlinear polarization responses directly in the time domain with superior excitation energy resolution near the electronic bandgap.The third-order nonlinear electric polarization P(3) serves as an in situ probe of a material’s polarizability and governs the ultrafast macroscopic response to an incident light field. This is employed in a variety of spectroscopies, such as (magneto-) OKE (12, 13), coherent phonon spectroscopy (14, 15), and four-wave mixing (FWM) in general (11). Recently, OKE has been applied to LHP single crystals: Below the bandgap, the dominating nonoscillatory Kerr response of MAPbBr₃ (MA = CH₃NH₃) compared to its all-inorganic counterpart CsPbBr3 was previously attributed to the transient polarization anisotropy caused by liquidlike reorientation dynamics of organic cations (2) and lattice disorder (5). The exponentially decaying responses with above-gap excitations were discussed in relation to polaron formation in both materials (5). Interestingly, for excitation energies close to the bandgap in CsPbBr₃ at room temperature, time-resolved OKE reveals complex oscillatory features. Such oscillatory transient birefringence signals are usually attributed to coherently excited collective modes, such as phonons (15–17) or magnons (18, 19), but the strong dependence of the oscillatory frequency on pump-photon energy in OKE seems to contradict these origins in LHPs (5). In this work, we unveil a unified source for the Kerr responses in single-crystal LHPs by tracing contributions from hyperpolarizability and the peculiar light propagation close to electronic transitions.     

Circulating T-Cell Subsets,Monocytes, and Natural Killer Cells in Peripartum Cardiomyopathy: Results From the Multicenter IPAC Study

Objective

The aim of this work was to evaluate the hypothesis that the distribution of circulating immune cell subsets, or their activation state, is significantly different between peripartum cardiomyopathy (PPCM) and healthy postpartum (HP) women.

Antiretroviral therapy immunologic non-response in a Brazilian population: association study using pharmaco- and immunogenetic markers

Background

Antiretroviral therapy (ART) saved millions from HIV-1 infection and AIDS, but some patients do not experience adequate CD4+ T cells gain despite achieving viral suppression. The genetic component of this condition is not yet completely elucidated.