Recent Advances in Nanotechnology with Nano-Phytochemicals: Molecular Mechanisms and Clinical Implications in Cancer Progression.

Biocompatible nanoparticles (NPs) containing polymers, lipids (liposomes and micelles), dendrimers, ferritin, carbon nanotubes, quantum dots, ceramic, magnetic materials, and gold/silver have contributed to imaging diagnosis and targeted cancer therapy. However, only some NP drugs, including Doxil® (liposome-encapsulated doxorubicin), Abraxane® (albumin-bound paclitaxel), and Oncaspar® (PEG-Asparaginase), have emerged on the pharmaceutical market to date. By contrast, several phytochemicals that were found to be effective in cultured cancer cells and animal studies have not shown significant efficacy in humans due to poor bioavailability and absorption, rapid clearance, resistance, and toxicity. Research to overcome these drawbacks by using phytochemical NPs remains in the early stages of clinical translation. Thus, in the current review, we discuss the progress in nanotechnology, research milestones, the molecular mechanisms of phytochemicals encapsulated in NPs, and clinical implications. Several challenges that must be overcome and future research perspectives are also described.

CP-25, a compound derived from paeoniflorin: research advance on its pharmacological actions and mechanisms in the treatment of inflammation and immune diseases.

Total glycoside of paeony (TGP) has been widely used to treat inflammation and immune diseases in China. Paeoniflorin (Pae) is the major active component of TGP. Although TGP has few adverse drug reactions, the slow onset and low bioavailability of Pae limit its clinical use. Enhanced efficacy without increased toxicity is pursued in developing new agents for inflammation and immune diseases. As a result, paeoniflorin-6'-O-benzene sulfonate (CP-25) derived from Pae, is developed in our group, and exhibits superior bioavailability and efficacy than Pae. Here we describe the development process and research advance on CP-25. The pharmacokinetic parameters of CP-25 and Pae were compared in vivo and in vitro. CP-25 was also compared with the first-line drugs methotrexate, leflunomide, and hydroxychloroquine in their efficacy and adverse effects in arthritis animal models and experimental Sjögren's syndrome. We summarize the regulatory effects of CP-25 on inflammation and immune-related cells, elucidate the possible mechanisms, and analyze the therapeutic prospects of CP-25 in inflammation and immune diseases, as well as the diseases related to its potential target G-protein-coupled receptor kinases 2 (GRK2). This review suggests that CP-25 is a promising agent in the treatment of inflammation and immune diseases, which requires extensive investigation in the future. Meanwhile, this review provides new ideas about the development of anti-inflammatory immune drugs.

In Vitro Determination of the Immunogenic Impact of Nanomaterials on Primary Peripheral Blood Mononuclear Cells.

Investigation of the potential for nanomaterials to generate immunogenic effects is a key aspect of a robust preclinical evaluation. In combination with physicochemical characterization, such assessments also provide context for how material attributes influence biological outcomes. Furthermore, appropriate models for these assessments allow accurate in vitro to in vivo extrapolation, which is vital for the mechanistic understanding of nanomaterial action. Here we have assessed the immunogenic impact of a small panel of commercially available and in-house prepared nanomaterials on primary human peripheral blood mononuclear cells (PBMCs). A diethylaminoethyl-dextran (DEAE-dex) functionalized superparamagnetic iron oxide nanoparticle (SPION) generated detectable quantities of tumor necrosis factor α (TNFα), interleukin-1ß (IL-1ß), and IL-10, the only tested material to do so. The human leukemia monocytic cell line THP-1 was used to assess the potential for the nanomaterial panel to affect cellular oxidation-reduction (REDOX) via measurement of reactive oxygen species and reduced glutathione. Negatively charged sulfonate-functionalized polystyrene nanoparticles demonstrated a size-related trend for the inhibition of caspase-1, which was not observed for amine-functionalized polystyrene of similar sizes. Silica nanoparticles (310 nm) resulted in a 93% increase in proliferation compared to the untreated control (p < 0.01). No other nanomaterial treatments resulted in significant change from that of unstimulated PBMCs. Responses to the nanomaterials in the assays described demonstrate the utility of primary cells as ex vivo models for nanomaterial biological impact.

High-Salt Diet Causes Expansion of the Lymphatic Network and Increased Lymph Flow in Skin and Muscle of Rats.

Objective- A commonly accepted pivotal mechanism in fluid volume and blood pressure regulation is the parallel relationship between body Na+ and extracellular fluid content. Several recent studies have, however, shown that a considerable amount of Na+ can be retained in skin without commensurate water retention. Here, we asked whether a salt accumulation shown to result in VEGF (vascular endothelial growth factor)-C secretion and lymphangiogenesis had any influence on lymphatic function. Approach and Results- By optical imaging of macromolecular tracer washout in skin, we found that salt accumulation resulted in an increase in lymph flow of 26% that was noticeable only after including an overnight recording period. Surprisingly, lymph flow in skeletal muscle recorded with a new positron emission tomography/computed tomography method was also increased after salt exposure. The transcapillary filtration was unaffected by the high-salt diet and deoxycorticosterone-salt treatment, suggesting that the capillary barrier was not influenced by the salt accumulation. A significant reduction in lymph flow after depletion of macrophages/monocytes by clodronate suggests these cells are involved in the observed lymph flow response, together with collecting vessels shown here to enhance their contraction frequency as a response to extracellular Na+. Conclusions- The observed changes in lymph flow suggest that the lymphatics may influence long-term regulation of tissue fluid balance during salt accumulation by contributing to fluid homeostasis in skin and muscle. Our studies identify lymph clearance as a potential disease-modifying factor that might be targeted in conditions characterized by salt accumulation like chronic kidney disease and salt-sensitive hypertension.

Comparative study of immunopathophysiological responses induced by B. melitensis and its lipopolysaccharide in mouse model infected via intranasal route of exposure.

In this study, we developed a mouse model and characterized the effects of intranasal inoculation of virulent Brucella melitensis strain 16M and its lipopolysaccharide (LPS). The effects of the exposure were compared with respective control groups. Both Brucella melitensis-infected and LPS-infected groups showed no significant clinical presentation with minor relevance in the mortality associated with the infection. In Brucella melitensis-infected group, significant histopathological changes in comparison to the LPS infected group with increase bacterial burden in the lungs, reproductive and reticuloendothelial organs were observed. However, both infected groups showed elevated levels of pro-inflammatory cytokine expression (IL-1ß and IL6) and antibody production (IgM an IgG) as early as 3 days post-infection with predominance in LPS infected group. In contrast, low levels of sex related hormonal changes was recorded in both infected groups throughout the experimental period. This is the first detailed investigation comparing the infection progression and host responses in relation to the immunopathophysiological aspects in mouse model after intranasal inoculation with B. melitensis and its lipopolysaccharide. The study revealed a significant difference between infected and control groups with overlap in clinical, pathological, and immunological responses as well as sex related hormonal changes resulting from the infections.

The development and maintenance of the mononuclear phagocyte system of the chick is controlled by signals from the macrophage colony-stimulating factor receptor.

BACKGROUND: Macrophages have many functions in development and homeostasis as well as innate immunity. Recent studies in mammals suggest that cells arising in the yolk sac give rise to self-renewing macrophage populations that persist in adult tissues. Macrophage proliferation and differentiation is controlled by macrophage colony-stimulating factor (CSF1) and interleukin 34 (IL34), both agonists of the CSF1 receptor (CSF1R). In the current manuscript we describe the origin, function and regulation of macrophages, and the role of CSF1R signaling during embryonic development, using the chick as a model. RESULTS: Based upon RNA-sequencing comparison to bone marrow-derived macrophages grown in CSF1, we show that embryonic macrophages contribute around 2% of the total embryo RNA in day 7 chick embryos, and have similar gene expression profiles to bone marrow-derived macrophages. To explore the origins of embryonic and adult macrophages, we injected Hamburger-Hamilton stage 16 to 17 chick embryos with either yolk sac-derived blood cells, or bone marrow cells from EGFP+ donors. In both cases, the transferred cells gave rise to large numbers of EGFP+ tissue macrophages in the embryo. In the case of the yolk sac, these cells were not retained in hatched birds. Conversely, bone marrow EGFP+ cells gave rise to tissue macrophages in all organs of adult birds, and regenerated CSF1-responsive marrow macrophage progenitors. Surprisingly, they did not contribute to any other hematopoietic lineage. To explore the role of CSF1 further, we injected embryonic or hatchling CSF1R-reporter transgenic birds with a novel chicken CSF1-Fc conjugate. In both cases, the treatment produced a large increase in macrophage numbers in all tissues examined. There were no apparent adverse effects of chicken CSF1-Fc on embryonic or post-hatch development, but there was an unexpected increase in bone density in the treated hatchlings. CONCLUSIONS: The data indicate that the yolk sac is not the major source of macrophages in adult birds, and that there is a macrophage-restricted, self-renewing progenitor cell in bone marrow. CSF1R is demonstrated to be limiting for macrophage development during development in ovo and post-hatch. The chicken provides a novel and tractable model to study the development of the mononuclear phagocyte system and CSF1R signaling.

[Pathogenic cells of rheumatic inflammation as the target of modern therapies]. / Pathogene Zellen der rheumatischen Entzündung als Ziele moderner Therapien.

In the 1970s and 1980s the course of rheumatoid arthritis (RA) could be defined as fateful despite the introduction of methotrexate as well as other immunosuppressive treatments. In most patients at this time RA was combined with an early disability due a progressive destruction of joints. In addition, comorbidity was known to be one of the major causes for a decreased life expectancy. These less than optimal options for treating RA patients led to intensive research in the pathogenesis with the aim to develop new treatment principles. Based on the increasing knowledge of pathogenically important mechanisms, so-called biologicals were developed targeting T and B cells and proinflammatory cytokines, such as tumor necrosis factor alpha. Over the past 10 years the repertoire of biologicals for treating RA has steadily and significantly increased, which was necessary especially for those patients classified as non-responders to available biological compounds. In the present overview cellular structures, T and B cells as well as cells of the monocyte/macrophage system are discussed as targets for immune interventions.

EVEN VISITING SCIENTISTS COULD MAKE DISCOVERIES IN MONTREAL.

This publication summarizes the scientific adventure with Professor Selye, and focuses on the specific effect of rare metal salts on reticuloendothelial functions. Rare earth metal ions markedly affect the functions of cells involved in inflammatory and immunological phenomena. The Kupffer cell blockade induced by GdCl3 is a generally accepted method for investigation of the physiological and pathophysiological roles of Kupffer cells. Potential beneficial effects of macrophage blockade have been demonstrated in different shock states, liver injury and obstructive jaundice.

Translational studies of phenotypic probes for the mononuclear phagocyte system and liposomal pharmacology.

As nanoparticles (NPs) are cleared via phagocytes of the mononuclear phagocyte system (MPS), we hypothesized that the function of circulating monocytes and dendritic cells (MO/DC) in blood can predict NP clearance (CL). We measured MO/DC phagocytosis and reactive oxygen species (ROS) production in mice, rats, dogs, and patients with refractory solid tumors. Pharmacokinetic studies of polyethylene glycol (PEG)-encapsulated liposomal doxorubicin (PEGylated liposomal doxirubicin [PLD]), CKD-602 (S-CKD602), and cisplatin (SPI-077) were performed at the maximum tolerated dose. MO/DC function was also evaluated in patients with recurrent epithelial ovarian cancer (EOC) administered PLD. Across species, a positive association was observed between cell function and CL of PEGylated liposomes. In patients with EOC, associations were observed between PLD CL and phagocytosis (R(2) = 0.43, P = 0.04) and ROS production (R(2) = 0.61, P = 0.008) in blood MO/DC. These findings suggest that probes of MPS function may help predict PEGylated liposome CL across species and PLD CL in patients with EOC.

Modification of a dioxygen carrier, hemoCD, with PEGylated dendrons for extension of circulation time in the bloodstream.

A supramolecular diatomic receptor, hemoCD, was modified with PEGylated dendrons to extend its circulation time in the bloodstream. The core component was 4-oxo-4-[[4-(10,15,20-tris(4-sulfonatophenyl)-21H,23H-porphin-5-yl)phenyl]amino]butanoic acid (Por-COOH). The building block of the dendrons was Fmoc-4-amino-4-(2-carboxyethyl)heptanedioic acid (FmocTA), which was condensed with α-amino-ω-methoxy-poly(ethylene glycol) (PEG(5000)-NH(2)) to yield an FmocG1-dendron. After deprotection, the G1-dendron was condensed with Por-COOH to yield G1-Por. A precursor (FmocNA) of an FmocG2-dendron was prepared via a condensation reaction of 4-amino-4-(2-t-butoxycarbonylethyl)heptanedioic acid di-t-butyl ester (TA-E) with FmocTA followed by hydrolysis of the resultant nona-carboxylic acid nona-t-butyl ester. Condensation of FmocNA with PEG(5000)-NH(2) yielded an FmocG2-dendron. After deprotection, the G2-dendron was condensed with Por-COOH to yield G2-Por. The ferrous complexes of G1- and G2-Pors formed stable 1:1 inclusion complexes with Py3CD, a per-O-methylated ß-cyclodextrin dimer with a pyridine linker, in aqueous solution yielding supramolecular complexes designated as G1-hemoCD and G2-hemoCD, respectively. Both G1- and G2-hemoCDs bound molecular oxygen, with the O(2) affinities (P(1/2)) of hemoCD, G1-, and G2-hemoCDs at pH 7.4 and 37 °C being 22, 20, and 20 Torr, respectively. The modification of hemoCD with the dendrons did not cause destabilization of the O(2) adducts via autoxidation, as indicated by their half-lives (t(1/2)) of 6.8, 6.1, and 5.5 h for hemoCD, G1-, and G2-hemoCDs, respectively. The blood concentration-time curves of G1- and G2-hemoCDs injected into the bloodstream of rats exhibited two phases, with the half-lives of the fast and slow decays being 0.45 and 5.3 h, respectively, for G1-hemoCD, and 0.20 and 12.8 h, respectively, for G2-hemoCD. The half-lives of hemoCD were 0.02 and 0.50 h, respectively. The circulation time of hemoCD was markedly extended by its modification with the PEGylated dendrons, which was very effective in protecting hemoCD against opsonization for uptake by the reticuloendothelial system.

[Structural changes of some organs in rats after a single intravenous injection of magnetite nanoparticles].

The aim of this investigation was to study the morphological changes of liver, lung, kidneys and spleen as well as of the cells of mononuclear pahagocyte system in 60 rats 1-40 days after a single intravenous injection of a suspension of magnetite nanoparticles. Moderate hemodynamic disturbances and focal necrotic changes were detected in the hepatic and renal parenchyma. In the lungs and spleen, only hemodynamic disturbances were found. The degree of morphological changes in rat liver, lungs, kidneys and spleen was decreased by day 10. Using Perls histochemical method, the accumulation of nanoparticles was detected in the cells of mononuclear phagocyte system of the organs studied.

Dichotomy between factors inducing the immunosuppressive enzyme IL-4-induced gene 1 (IL4I1) in B lymphocytes and mononuclear phagocytes.

MPhi and DC are key elements in the control of tissue homeostasis and response to insult. In this work, we demonstrate that MPhi and DC are the major producers of the phenylalanine catabolizing enzyme IL-4-induced gene 1 (IL4I1) under inflammatory conditions. IL4I1 was first described in B cells, which indeed can produce IL4I1 in vitro, although at much lower levels. In vivo, IL4I1 is highly expressed by MPhi and DC of Th1 granulomas (sarcoidosis, tuberculosis) but poorly detected in Th2 granulomas (schistosomiasis). In vitro, expression of the enzyme is induced in mononuclear phagocytes by various pro-inflammatory stimuli through the activation of the transcription factors NF-kappaB and/or STAT1. B cells also express IL4I1 in response to NF-kappaB-activating stimuli such as CD40L; however, in contrast to myeloid cells, B cells are insensitive to IFN-gamma but respond to stimulation of the IL-4/STAT6 axis. As we show that the expression of IL4I1 by a monocytic cell line inhibits T-cell proliferation and production of IFN-gamma and inflammatory cytokines, we propose that IL4I1 participates in the downregulation of Th1 inflammation in vivo.

Experimental investigation of the immunoregulatory and anti-inflammatory effects of the traditional Chinese medicine "Li-Yan Zhi-Ke Granule" for relieving chronic pharyngitis in rats.

Chronic pharyngitis, a chronic inflammation of the pharyngeal mucous membrane and submucous lymphoid tissues, is often caused by unsatisfactory treatment of acute pharyngitis or repeated occurrences of upper respiratory tract infection and is related to a high-dust environment. Traditional herbal pharmacotherapy is well known for combining plant species to create complex phytochemical mixtures in the attempt to ameliorate pathophysiological processes. The aim of current study is to investigate the effect of immunoregulation and anti-inflammation with the traditional Chinese medicine (TCM) "Li-Yan Zhi-Ke Granule" in rats. Determination of serum hemolysin and the carbon particle clearance test were performed. The results demonstrate that administration of the TCM "Li-Yan Zhi-Ke Granule" may improve the effect of phagocytosis by mononuclear macrophages and immune function in rats, and may also increase the immunoregulatory and anti-inflammatory responses of rats with chronic pharyngitis. This traditional drug could relieve the symptoms of sore throat and cough in rats with chronic pharyngitis.

Tumor disposition of pegylated liposomal CKD-602 and the reticuloendothelial system in preclinical tumor models.

Liposomes, such as pegylated-liposomal CKD-602 (S-CKD602), undergo catabolism by macrophages and dendritic cells (DCs) of the reticuloendothelial system (RES). The relationship between plasma and tumor disposition of S-CKD602 and RES was evaluated in mice bearing A375 melanoma or SKOV-3 ovarian xenografts. Area under the concentration-time curves (AUCs) of liposomal encapsulated, released, and sum total (encapsulated + released) CKD-602 in plasma, tumor, and tumor extracellular fluid (ECF) were estimated. A375 and SKOV-3 tumors were stained with cd11b and cd11c antibodies as measures of macrophages and DC. The plasma disposition of S-CKD602 was similar in both xenograft models. The ratio of tumor sum total AUC to plasma sum total AUC was 1.7-fold higher in mice bearing human SKOV-3 xenografts, compared with A375. The ratio of tumor ECF AUC to tumor sum total AUC was 2-fold higher in mice bearing human SKOV-3 xenografts, compared with A375. The staining of cd11c was 4.5-fold higher in SKOV-3, compared with A375 (P < 0.0001). The increased tumor delivery and release of CKD-602 from S-CKD602 in the ovarian xenografts, compared with the melanoma xenografts, was consistent with increased cd11c staining, suggesting that variability in the RES may affect the tumor disposition of liposomal agents.

Bidirectional pharmacodynamic interaction between pegylated liposomal CKD-602 (S-CKD602) and monocytes in patients with refractory solid tumors.

BACKGROUND: STEALTH(®) liposomal CKD-602 (S-CKD602), a camptothecin analog, is eliminated by the reticuloendothelial system (RES), which consists of cells, including monocytes. We evaluated the relationship between monocyte and absolute neutrophil counts (ANCs) in the blood and pharmacokinetic disposition of S-CKD602 and nonliposomal CKD-602 (NL-CKD602) in patients. METHODS: As part of a phase I study of S-CKD602 and phase I and II studies of NL-CKD602, the percent decreases in ANC and monocytes at their nadir were calculated. After S-CKD602, the amount of CKD-602 recovered in urine was measured. RESULTS: For S-CKD602 in patients <60 years, the percent decrease in ANC and monocytes were 43 ± 31 and 58 ± 26%, respectively (P = 0.001). For S-CKD602 in patients ≥60, the percent decrease in ANC and monocytes were 41 ± 31 and 45 ± 36%, respectively (P = 0.50). For NL-CKD602 (n = 42), the percent decrease in ANC and monocytes were similar (P > 0.05). For S-CKD602, the relationship between the percent decrease in monocytes and CKD-602 recovered in urine was stronger in patients <60 (R(2) = 0.82), compared with patients ≥60 (R(2) = 0.30). CONCLUSIONS: Monocytes are more sensitive to S-CKD602, compared with neutrophils, and the increased sensitivity is related to the liposomal formulation, not CKD-602. These results suggest that monocytes engulf S-CKD602, which causes the release of CKD-602 from the liposome and toxicity to the monocytes, and that the effects are more prominent in patients <60.

Liposomes coloaded with iopamidol/lipiodol as a RES-targeted contrast agent for computed tomography imaging.

PURPOSE: The need for computed tomography (CT) of reticuloendothelial system (RES)-rich organs such as the liver is increasing, particularly in patients with suspected hepatic metastasis. CT images of the liver have been improved by encapsulating currently used, water-soluble iodine contrast agent in liposomes. The present study was performed to investigate a possibility to overcome the limitations of entrapped iodine in liposomes by preparing liposomes co-loaded with iopamidol, a water-soluble iodinated compound, and lipiodol, an iodized oil. METHODS: Iopamidol and lipiodol were simultaneously loaded in liposomes by modified reverse-phase evaporation method. The entrapped iodine concentration, mean particle size and polydispersity index of resulting liposomes were evaluated. Following intravenous injection of these liposomes into rats, CT scanning was performed. RESULTS: Simultaneous loading of iopamidol and lipiodol into liposomes resulted in entrapped iodine concentrations as high as 49.2 iodine mg/ml. The mean particle size was 280 nm, and the mean polydispersity index was 0.230. CT scanning with these iopamidol/lipiodol (I/L) liposomes into rats resulted in more pronounced and more persistent increases in RES-rich organs, liver and spleen, compared with free liposomes or liposomes loaded with iopamidol alone. CONCLUSIONS: These findings indicate that I/L liposomes have the potential to allow thorough CT examination of RES-rich organs.

A pH-Responsive System Based on Fluorescence Enhanced Gold Nanoparticles for Renal Targeting Drug Delivery and Fibrosis Therapy.

BACKGROUND: Stimuli-responsive gold nano-assemblies have attracted attention as drug delivery systems in the biomedical field. However, there are challenges achieving targeted delivery and controllable drug release for specific diseases. MATERIALS AND METHODS: In this study, a glutathione (GSH)-modified fluorescent gold nanoparticle termed AuLA-GSH was prepared and a Co2+-induced self-assembly drug delivery platform termed AuLA-GSH-Co was constructed. Both the pH-responsive character and drug loading behavior of AuLA-GSH-Co were studied in vitro. Kidney-targeting capability was investigated in vitro and in vivo. Finally, the anti-fibrosis efficiency of AuLA-GSH-Co in a mouse model of unilateral ureteral obstruction (UUO) was explored. RESULTS: AuLA-GSH-Co was sensitive to pH changes and released Co2+ in acidic conditions, allowing it to have controllable drug release abilities. AuLA-GSH-Co was found to improve cellular uptake of Co2+ ions compared to CoCl2 in vitro. AuLA-GSH exhibited specific renal targeting and prolonged renal retention time with low non-specific accumulation in vivo. Moreover, the anti-fibrosis efficiency of AuLA-GSH-Co was higher compared to CoCl2 in a mouse model of unilateral ureteral obstruction (UUO). CONCLUSION: AuLA-GSH-Co could greatly enhance drug delivery efficiency with renal targeting capability and obviously relieve renal fibrosis, providing a promising strategy for renal fibrosis therapy.

Rat IgG mediated circulatory cell depletion in mice requires mononuclear phagocyte system and is facilitated by complement.

Application of exogenous Abs targeting cell surface Ags has been widely used as an experimental approach to induce cell depletion or to inhibit receptor functionality. Moreover, Ab therapy is emerging as one of the mainstream strategies for cancer treatment. Previous studies on the mechanisms of Ab-mediated cell depletion mainly employed Abs from the same species as the research subject. However, there has been a recent trend toward using xenogeneic (cross-species) Abs to achieve cell depletion or block receptor-ligand interactions; with rat Abs used in mice being the most common approach. Considering the molecular differences in Abs from different species, the mechanism(s) of xenogeneic Ab-mediated cell depletion is likely to be different than species-matched Ab supplementation. The current work describes our efforts to identify the mechanism of rat anti-mouse Ly6G (clone: 1A8) mAb mediated depletion of mouse neutrophils. The results showed that neutrophils circulating in the blood but not those in the bone marrow are depleted, and depletion depends on mononuclear phagocyte system, especially liver Kupffer cells that efficiently capture and phagocytize targeted cells. Interestingly, whereas species-matched Ab depletion does not require complement functionality, we found that complement activation significantly facilitates cross-species neutrophil depletion. Finally, we found that some rat mAbs (anti-C5aR, anti-CD11a, anti-CD11b, and anti-VLA4) used to block cell surface receptors also induce cell depletion. Thus, our work strongly recommends controlling for cell depletion effect when using these Abs for receptor blockade purposes.

Amyloidosis induced in mice by Escherichia coli endotoxin.

Amyloidosis was produced in mice by repeated subcutaneous injections of 0.5-or 0.005-milligram amounts of Escherichia coli endotoxin. Of the two strains of mice examined, amyloidosis was induced more readily in one than in the other. The ability of endotoxin to induce amyloidosis lends support to the view that stimulation of reticuloendothelial cells leads to amyloid formation.

Reticuloendothelial blockade: effect of puromycin on opsonin-dependent recovery.

Reticuloendothelial blockade induced by the administration of a gelatinized "reticuloendothelial test lipid emulsion" is due to a loss of opsonic activity in the plasma. Recovery from blockade, which is associated with restoration of plasma opsonins, was inhibited by the administration of puromycin. The effect of puromycin appears to be mediated by inhibition of opsonin formation rather than a puromycin-induced macrophage defect in phagocytosis.