Inhaled remdesivir reduces viral burden in a nonhuman primate model of SARS-CoV-2 infection

Remdesivir (RDV) is a nucleotide analog prodrug with demonstrated clinical benefit in patients with coronavirus disease 2019 (COVID-19). In October 2020, the US FDA approved intravenous (IV) RDV as the first treatment for hospitalized COVID-19 patients. Furthermore, RDV has been approved or authorized for emergency use in more than 50 countries. To make RDV more convenient for non-hospitalized patients earlier in disease, alternative routes of administration are being evaluated. Here, we investigated the pharmacokinetics and efficacy of RDV administered by head dome inhalation in African green monkeys (AGM). Relative to an IV administration of RDV at 10 mg/kg, an approximately 20-fold lower dose administered by inhalation produced comparable concentrations of the pharmacologically active triphosphate in lower respiratory tract tissues. Distribution of the active triphosphate into the upper respiratory tract was also observed following inhaled RDV exposure. Inhalation RDV dosing resulted in lower systemic exposures to RDV and its metabolites as compared with IV RDV dosing. An efficacy study with repeated dosing of inhaled RDV in an AGM model of SARS-CoV-2 infection demonstrated reductions in viral replication in bronchoalveolar lavage fluid and respiratory tract tissues compared with placebo. Efficacy was observed with inhaled RDV administered once daily at a pulmonary deposited dose of 0.35 mg/kg beginning approximately 8 hours post-infection. Moreover, the efficacy of inhaled RDV was similar to that of IV RDV administered once at 10 mg/kg followed by 5 mg/kg daily in the same study. Together, these findings support further clinical development of inhalation RDV.

Phytol, not propylene glycol, causes severe pulmonary injury after inhalation dosing in Sprague-Dawley rats

Introduction: The use of vaping pens for inhalation of cannabinoid derived products is rising and has become a popular alternative to smoking combustible products. For efficient product delivery, additives are sometimes added and vaping pens often may include compounds like Phytol or Propylene Glycol as thinning agents. This study aimed at comparing Phytol and Propylene Glycol with respect to potential toxicity and safe use in vaping products.Methods: Male and female Sprague Dawley rats were exposed to 5 mg/L of Phytol or Propylene Glycol for up to 6 hours over up to 14 days and monitored for clinical signs and changes in body weight. Gross necropsy and histopathology of respiratory tissue was performed to assess potential adverse effects.Results: Phytol exposed animals expressed severe clinical signs, body weight loss and mortality after one or two exposure days, leading to termination of all dose groups for this compound. Lung weights were increased and respiratory tissue was severely affected, demonstrating dose-responsive tissue degeneration, necrosis, edema, hemorrhage and inflammation. Propylene Glycol exposed animals did not show any adverse reactions after 14 days of high dose exposure.Conclusions: For Phytol, a low observed adverse effect level (LOAEL) was determined at ≤109.0/10.9 mg/kg/day presented/deposited dose and therefore its use as excipient in vaping product is not recommend; a safe exposure range was not established for Phytol. Propylene Glycol, in contrast, is considered safe with a no observed adverse effect level (NOAEL) at 1151.7/115.2 mg/kg/day presented/deposited dose in rats.

Inhaled Submicron Particle Paclitaxel (NanoPac) Induces Tumor Regression and Immune Cell Infiltration in an Orthotopic Athymic Nude Rat Model of Non-Small Cell Lung Cancer

Background: This study evaluated the antineoplastic and immunostimulatory effects of inhaled (IH) submicron particle paclitaxel (NanoPac^®) in an orthotopic non-small cell lung cancer rodent model.

Methods: Male nude rats were whole body irradiated, intratracheally instilled with Calu-3 cancer cells and divided into six treatment arms (n = 20 each): no treatment (Group 1); intravenous nab-paclitaxel at 5.0 mg/kg once weekly for 3 weeks (Group 2); IH NanoPac at 0.5 or 1.0 mg/kg, once weekly for 4 weeks (Groups 3 and 4), or twice weekly for 4 weeks (Groups 5 and 6). Upon necropsy, left lungs were paraffin embedded, serially sectioned, and stained for histopathological examination. A subset was evaluated by immunohistochemistry (IHC), anti-pan cytokeratin staining AE1/AE3⁺ tumor cells and CD11b⁺ staining dendritic cells, natural killer lymphocytes, and macrophage immune cells (n = 2, Group 1; n = 3 each for Groups 2–6). BCL-6 staining identified B lymphocytes (n = 1 in Groups 1, 2, and 6).

Results: All animals survived to scheduled necropsy, exhibited no adverse clinical observations due to treatment, and gained weight at the same rate throughout the study. Histopathological evaluation of Group 1 lung samples was consistent with unabated tumor growth. Group 2 exhibited regression in 10% of animals (n = 2/20). IH NanoPac-treated groups exhibited significantly higher tumor regression incidence per group (n = 11–13/20; p < 0.05, χ²). IHC subset analysis revealed tumor-nodule cluster separation, irregular borders between tumor and non-neoplastic tissue, and an increased density of infiltrating CD11b⁺ cells in Group 2 animals (n = 2/3) and in all IH NanoPac-treated animals reviewed (n = 3/3 per group). A single animal in Group 4 and Group 6 exhibited signs of pathological complete response at necropsy with organizing stroma and immune cells replacing areas presumed to have previously contained adenocarcinoma nodules.

Conclusion: Tumor regression and immune cell infiltration were observed in all treatment groups, with an increased incidence noted in animals receiving IH submicron particle paclitaxel treatment.

Pharmacokinetic Profile of Inhaled Submicron Particle Paclitaxel (NanoPac®) in a Rodent Model

Background: Inhaled chemotherapeutics may enhance pulmonary drug exposure to malignant lesions in the lung without substantially contributing to systemic toxicities. The pharmacokinetic profile of inhaled submicron particle paclitaxel (NanoPac^®) in healthy rodent plasma and lung tissue is evaluated here to determine administration proof-of-principle.

Methods: Healthy male Sprague Dawley rats received paclitaxel in one of three arms: intravenous nab-paclitaxel at 2.9 mg/kg (IVnP), inhaled NanoPac low dose (IHNP-LD) at 0.38 mg/kg, or inhaled NanoPac high dose (IHNP-HD) at 1.18 mg/kg. Plasma and lung tissue paclitaxel concentrations were determined using ultraperformance liquid chromatography tandem mass spectrometry from animals sacrificed at 10 time points ranging up to 2 weeks after administration. Peak concentration (C_max), apparent residence half-life (T_1/2), exposure (AUC_(last)), and dose-normalized exposure (AUC_D(last)) were determined. Pulmonary histopathology was performed on rats sacrificed at the 336-hour time point.

Results: Paclitaxel was detectable and quantifiable in the rat lung for both inhaled NanoPac arms sampled at the final necropsy, 336 hours postadministration. Substantial paclitaxel deposition and retention resulted in an order of magnitude increase in dose-normalized pulmonary exposure over IVnP. Inhaled NanoPac arms had an order of magnitude lower plasma C_max than IVnP, but followed a similar plasma T_1/2 clearance (quantifiable only to 72 hours postadministration). Pulmonary histopathology found all treated animals indistinguishable from treatment-naive rats.

Conclusion: In the rodent model, inhaled NanoPac demonstrated substantial deposition and retention of paclitaxel in sampled lung tissue. Further research to determine NanoPac's toxicity profile and potential efficacy as lung cancer therapy is underway.

Radiation-induced impairment in lung lymphatic vasculature

BACKGROUND

The lymphatic vasculature has been shown to play important roles in lung injury and repair, particularly in lung fibrosis. The effects of ionizing radiation on lung lymphatic vasculature have not been previously reported.

METHODS AND RESULTS

C57Bl/6 mice were immobilized in a lead shield exposing only the thoracic cavity, and were irradiated with a single dose of 14 Gy. Animals were sacrificed and lungs collected at different time points (1, 4, 8, and 16 weeks) following radiation. To identify lymphatic vessels in lung tissue sections, we used antibodies that are specific for lymphatic vessel endothelial receptor 1 (LYVE-1), a marker of lymphatic endothelial cells (LEC). To evaluate LEC cell death and oxidative damage, lung tissue sections were stained for LYVE-1 and with TUNEL staining, or 8-oxo-dG respectively. Images were imported into ImageJ v1.36b and analyzed. Compared to a non-irradiated control group, we observed a durable and progressive decrease in the density, perimeter, and area of lymphatic vessels over the study period. The decline in the density of lymphatic vessels was observed in both subpleural and interstitial lymphatics. Histopathologically discernible pulmonary fibrosis was not apparent until 16 weeks after irradiation. Furthermore, there was significantly increased LEC apoptosis and oxidative damage at one week post-irradiation that persisted at 16 weeks.

CONCLUSIONS

There is impairment of lymphatic vasculature after a single dose of ionizing radiation that precedes architectural distortion and fibrosis, suggesting important roles for the lymphatic circulation in the pathogenesis of the radiation-induced lung injury.

Part 1. Biologic responses in rats and mice to subchronic inhalation of diesel exhaust from U.S. 2007-compliant engines: report on 1-, 3-, and 12-month exposures in the ACES bioassay

The Health Effects Institute and its partners conceived and funded a program to characterize the emissions from heavy-duty diesel engines compliant with the 2007 and 2010 on-road emissions standards in the United States and to evaluate indicators of lung toxicity in rats and mice exposed repeatedly to diesel exhaust (DE*) from 2007-compliant engines. The preliminary hypothesis of this Advanced Collaborative Emissions Study (ACES) was that 2007-compliant on-road diesel emissions ". . . will not cause an increase in tumor formation or substantial toxic effects in rats and mice at the highest concentration of exhaust that can be used . . . although some biological effects may occur." This hypothesis is being tested at the Lovelace Respiratory Research Institute (LRRI) by exposing rats by chronic inhalation as a carcinogenicity bioassay, measuring indicators of pulmonary toxicity in rats after 1, 3, 12, and 24-30 months of exposure (final time point depends on the survival of animals), and measuring similar indicators of pulmonary toxicity in mice after 1 and 3 months of exposure. This report provides results of exposures through 3 months in rats and mice. Emissions from a 2007-compliant, 500-horsepower-class engine and aftertreatment system operated on a variable-duty cycle were used to generate the animal inhalation test atmospheres. Four treatment groups were exposed to one of three concentrations (dilutions) of exhaust combined with crankcase emissions, or to clean air as a negative control. Dilutions of exhaust were set to yield average integrated concentrations of 4.2, 0.8, and 0.1 ppm nitrogen dioxide (NO2). Exposure atmospheres were analyzed by daily measurements of key components and periodic detailed physical-chemical characterizations. Exposures were conducted 16 hr/dy (overnight), 5 dy/wk. Rats were evaluated for hematology, serum chemistry, bronchoalveolar lavage (BAL), lung cell proliferation, and histopathology after 1 month of exposure, and the same indicators plus pulmonary function after 3 months. Mice were evaluated for BAL, lung cell proliferation, and respiratory tract histopathology after 1 month of exposure, and the same indicators plus hematology and serum chemistry after 3 months. Samples from both species were collected for ancillary studies performed by investigators who were not at LRRI and were funded separately. Exposures were accomplished as planned, with average integrated exposure concentrations within 20% of the target dilutions. The major components were the gaseous inorganic compounds, nitrogen monoxide (NO), NO2, and carbon monoxide (CO). Minor components included low concentrations of diesel particulate matter (DPM) and volatile and semivolatile organic compounds (VOCs and SVOCs). There were no exposure-related differences in mortality or clinically evident morbidity. Among the more than 100 biologic response variables evaluated, the majority showed no significant difference from control as a result of exposure to DE. There was evidence of early lung changes in the rats, accompanied by a number of statistically significant increases in inflammatory and oxidative stress indicators, and some evidence of subtle changes in pulmonary function. In general, statistically significant effects were observed only at the highest exposure level. The mice did not have the same responses as the rats, but did have small but statistically significant increases in lavage neutrophils and the cytokine IL-6 at 1 month (but not at 3 months). These findings suggest that the rats were more sensitive than mice to the subchronic exposures.

Determination of N2-hydroxymethyl-dG adducts in the nasal epithelium and bone marrow of nonhuman primates following 13CD2-formaldehyde inhalation exposure

The presence of endogenous and exogenous N(2)-hydroxymethyl-dG adducts in DNA from the nasal mucosa and bone marrow of cynomolgus macaques exposed to 1.9 and 6.1 ppm of [(13)CD(2)]-formaldehyde for 6 h a day for 2 consecutive days was investigated using a highly sensitive nano-UPLC-MS/MS method with a limit of detection of 20 amol. Both exogenous and endogenous adducts were readily detected and quantified in the nasal tissues of both exposure groups, with an exposure dependent increase in exogenous adducts observed. In contrast, only endogenous adducts were detectable in the bone marrow, even though ∼10 times more DNA was analyzed.

Primary pneumonic plague in the African Green monkey as a model for treatment efficacy evaluation

BACKGROUND

Primary pneumonic plague is rare among humans, but treatment efficacy may be tested in appropriate animal models under the FDA 'Animal Rule'.

METHODS

Ten African Green monkeys (AGMs) inhaled 44-255 LD(50) doses of aerosolized Yersinia pestis strain CO92. Continuous telemetry, arterial blood gases, chest radiography, blood culture, and clinical pathology monitored disease progression.

RESULTS

Onset of fever, >39°C detected by continuous telemetry, 52-80 hours post-exposure was the first sign of systemic disease and provides a distinct signal for treatment initiation. Secondary endpoints of disease severity include tachypnea measured by telemetry, bacteremia, extent of pneumonia imaged by chest x-ray, and serum lactate dehydrogenase enzyme levels.

CONCLUSIONS

Inhaled Y. pestis in the AGM results in a rapidly progressive and uniformly fatal disease with fever and multifocal pneumonia, serving as a rigorous test model for antibiotic efficacy studies.

Diagnosis and treatment of pulmonary arterial hypertension and atrial fibrillation in an adult chimpanzee (Pan troglodytes)

This report describes the diagnosis and treatment of pulmonary arterial hypertension (PAH) in an adult male captive chimpanzee. Although cardiovascular disease in general is common in human and great apes, diagnosis and treatment of PAH in nonhuman primates are uncommon. In the case we present, the adult chimpanzee was diagnosed with an arrhythmia during an annual physical examination and later with PAH during a scheduled cardiovascular evaluation. PAH can either be primary or secondary and can lead to right ventricular overload and heart failure. This description is the first case study of pulmonary arterial hypertension in a great ape species.

Clinical and pathologic features of cynomolgus macaques (Macaca fascicularis) infected with aerosolized Yersinia pestis

Since the anthrax attacks of 2001, the emphasis on developing animal models of aerosolized select agent pathogens has increased. Many scientists believe that nonhuman primate models are the most appropriate to evaluate pulmonary response to, vaccines for, and treatments for select agents such as Yersinia pestis (Y. pestis), the causative agent of plague. A recent symposium concluded that the cynomolgus macaque (Macaca fascicularis) plague model should be characterized more fully. To date, a well-characterized cynomolgus macaque model of pneumonic plague using reproducible bioaerosols of viable Y. pestis has not been published. In the current study, methods for creating reproducible bioaerosols of viable Y. pestis strain CO92 (YpCO92) and pneumonic plague models were evaluated in 22 Indonesian-origin cynomolgus macaques. Five macaques exposed to doses lower than 250 CFU remained free of any indication of plague infection. Fifteen macaques developed fever, lethargy, and anorexia indicative of clinical plague. The 2 remaining macaques died without overt clinical signs but were plague-positive on culture and demonstrated pathology consistent with plague. The lethal dose of plague in humans is reputedly less than 100 organisms; in this study, 66 CFU was the dose at which half of the macaques developed fever and clinical signs (ED(50)), The Indonesian cynomolgus macaque reproduces many aspects of human pneumonic plague and likely will provide an excellent model for studies that require a macaque model.

Pulmonary and Systemic Immune Response to Inhaled Multiwalled Carbon Nanotubes

Inhalation of multiwalled carbon nanotubes (MWCNTs) at particle concentrations ranging from 0.3 to 5 mg/m3 did not result in significant lung inflammation or tissue damage, but caused systemic immune function alterations. C57BL/6 adult (10- to 12-week) male mice were exposed by whole-body inhalation to control air or 0.3, 1, or 5 mg/m3 respirable aggregates of MWCNTs for 7 or 14 days (6 h/day). Histopathology of lungs from exposed animals showed alveolar macrophages containing black particles; however, there was no inflammation or tissue damage observed. Bronchial alveolar lavage fluid also demonstrated particle-laden macrophages; however, white blood cell counts were not increased compared to controls. MWCNT exposures to 0.3 mg/m3 and higher particle concentrations caused nonmonotonic systemic immunosuppression after 14 days but not after 7 days. Immunosuppression was characterized by reduced T-cell-dependent antibody response to sheep erythrocytes as well as T-cell proliferative ability in presence of mitogen, Concanavalin A. Assessment of nonspecific natural killer (NK) cell activity showed that animals exposed to 1 mg/m(3) had decreased NK cell function. Gene expression analysis of selected cytokines and an indicator of oxidative stress were assessed in lung tissue and spleen. No changes in gene expression were observed in lung; however, interleukin-10 (IL-10) and NAD(P)H oxidoreductase 1 mRNA levels were increased in spleen.

Comparative oncology of lung tumors

Toxicologic pathologists need to understand the comparative oncology of lung tumors because lung cancer is a common and serious cancer in the human population. Lung cancer in humans is known to be caused by cigarette smoke and a number of other carcinogens in the environment. Animal studies are needed to elucidate possible interactions with other potential carcinogens in environmental or occupational settings. In addition, knowledge of dose-response relationships and potential synergistic effects are needed to minimize harmful effects. Understanding the pathogenesis of common lung tumors will also aid in the prevention, diagnosis and treatment of the disease. Toxicologic pathologists need to remember several important points about lung tumors. The lung cancer response varies among species. Important factors in this variation are the nature of the administered carcinogen, the tissue dose of the carcinogen, the mode of exposure, the sensitivity of the test animal species and the similarity to the human response. Studies of molecular changes are important new tools to understanding lung carcinogenesis. For example, the molecular changes in lung tumors of mice and humans have a number of similarities that may be important in evaluating the significance of compound-induced lung tumors in mice.

Gasoline exhaust emissions induce vascular remodeling pathways involved in atherosclerosis

Epidemiological evidence indicates that environmental air pollutants are positively associated with the development of chronic vascular disease; however, the mechanisms involved have not been fully elucidated. In the present study we examined molecular pathways associated with chronic vascular disease in atherosclerosis-prone apolipoprotein E-deficient (ApoE(-/-)) mice, including markers of vascular remodeling and oxidative stress, in response to exposure to the ubiquitous environmental pollutant, gasoline engine emissions. ApoE(-/-) mice, on a high-fat diet, were exposed by inhalation to either filtered air; 8, 40, or 60 mug/m(3) particulate matter whole exhaust; or filtered exhaust with gases matching the 60-mug/m(3) concentration, for 7 weeks. Aortas and plasma were collected and assayed for changes in histochemical markers, real-time reverse transcriptase-polymerase chain reaction, and indicators of oxidative damage. Inhalational exposure to gasoline engine emissions resulted in increased aortic mRNA expression of matrix metalloproteinase-3 (MMP-3), MMP-7, and MMP-9, tissue inhibitor of metalloproteinases-2, endothelin-1 and heme oxygenase-1 in ApoE(-/-) mice; increased aortic MMP-9 protein levels were confirmed through immunohistochemistry. Elevated reactive oxygen species were also observed in arteries from exposed animals, despite absence of plasma markers. Similar findings were also observed in the aortas of ApoE(-/-) mice exposed to particle-filtered atmosphere, implicating the gaseous components of the whole exhaust in mediating the expression of markers associated with the vasculopathy. These findings demonstrate that exposure to gasoline engine emissions results in the transcriptional upregulation of factors associated with vascular remodeling, as well as increased markers of vascular oxidative stress, which may contribute to the progression of atherosclerosis and reduced stability of vulnerable plaques.

Composition, Toxicity, and Mutagenicity of Particulate and Semivolatile Emissions from Heavy-Duty Compressed Natural Gas-Powered Vehicles

Particulate matter (PM) and vapor-phase semivolatile organic compounds (SVOC) were collected from three buses fueled by compressed natural gas. The bus engines included a well-functioning, conventional engine; a "high emitter" engine; and a new technology engine with an oxidation catalyst. Chemical analysis of the emissions showed differences among these samples, with the high emitter sample containing markers of engine oil constituents. PM + SVOC samples were also collected for mutagenicity and toxicity testing. Extraction efficiencies from the collection media were lower than for similarly collected samples from gasoline or diesel vehicles. Responses to the recovered samples were compared on the basis of exhaust volume, to incorporate the emission rates into the potency factors. Mutagenicity was assessed by Salmonella reverse mutation assay. Mutagenicity was greatest for the high emitter sample and lowest for the new technology sample. Metabolic activation reduced mutagenicity in strain TA100, but not TA98. Toxicity, including inflammation, cytotoxicity, and parenchymal changes, was assessed 24 h after intratracheal instillation into rat lungs. Lung responses were generally mild, with little difference between the responses to equivalent volumes of emissions from the normal emitter and the new technology, but greater responses for the high emitter. These emission sample potencies are further compared on the basis of recovered mass with previously reported samples from normal and high-emitter gasoline and diesel vehicles. While mutagenic potencies for the CNG emission samples were similar to the range observed in the gasoline and diesel emission samples, lung toxicity potency factors were generally lower than those for the gasoline and diesel samples.

Expression and function of CCAAT/enhancer binding proteinbeta (C/EBPbeta) LAP and LIP isoforms in mouse mammary gland, tumors and cultured mammary epithelial cells

CCAAT/Enhancer binding proteins (C/EBPs) play important roles in the regulation of cell growth and differentiation. This study investigated the expression and function of C/EBPbeta isoforms in the mouse mammary gland, mammary tumors, and a nontransformed mouse mammary epithelial cell line (HC11). C/EBPbeta mRNA levels are 2-5-fold higher in mouse mammary tumors derived from MMTV/c-neu transgenic mice compared with lactating and involuting mouse mammary gland. The "full-length" 38 kd C/EBPbeta LAP ("Liver-enriched Activator Protein") isoform is the predominant C/EBPbeta protein isoform in mammary tumor whole cell lysates, however, the truncated 20 kd C/EBPbeta LIP ("Liver-enriched Inhibitory Protein") isoform is also present at detectable levels (mean LAP:LIP ratio 5.3:1). The mammary tumor C/EBPbeta LAP:LIP ratio decreases 70% (from 5.3:1 to 1.6:1) when lysate preparation is switched from a rapid whole cell lysis protocol to a multistep nuclear/cytoplasmic fractionation protocol. In contrast to mammary tumors, only the C/EBPbeta LAP isoform is detectable in the mammary gland whole cell and nuclear lysates; the truncated "LIP" isoform is undetectable regardless of isolation protocol. Ectopic over expression of C/EBPbeta LIP or C/EBPbeta LAP did not alter HC11 growth rates. However, C/EBPbeta LIP over expressing HC11 cells (LAP:LIP ratio of approximately 1:1) exhibited a consistent 2-4 h delay in G(0)/S phase transition. C/EBPbeta LIP overexpressing HC11 cells did not express beta-casein mRNA (mammary epithelial cell differentiation marker) in response to lactogenic hormones. This defect in beta-casein expression was not corrected by carrying out the differentiation protocol in the presence of an artificial extracellular matrix. These results demonstrate that the "full-length" C/EBPbeta LAP isoform is the predominant C/EBPbeta protein isoform expressed in mouse mammary gland in vivo and mouse mammary epithelial cell cultures in vitro. C/EBPbeta LIP detected in mammary tumor lysates may result from in vivo production or ex vivo isolation-induced proteolysis of C/EBPbeta LAP. Ectopic overexpression of C/EBPbeta LIP (LAP:LIP ratio of approximately 1:1) inhibits mammary epithelial cell differentiation (beta-casein expression).

Neuron-specific enolase and chromogranin A as markers of neuroendocrine tumours

Circulating neuron-specific enolase (NSE) and chromogranin A (CgA) were measured in 128 patients with neuroendocrine tumours (NET) to compare their sensitivity and specificity, to investigate factors associated with elevated serum levels and to determine the usefulness of these markers in the follow-up of NET patients. NSE (Cispack NSE, Cis Bio International, Gif-sur-Yvette, France; normal <12.5 microg l(-1)), and chromogranin A (CgA-Riact, Cis Bio International, normal <100 microg l(-1)) were measured in 128 patients without renal insufficiency. There were 99 patients with gastroenteropancreatic (GEP) NET, 19 with medullary thyroid carcinoma and ten with phaeochromocytoma. Fifty-three patients with non-NET were studied as controls. Serum NSE and CgA levels were elevated in 48 (38%) and 76 (59%) of the 128 NET patients respectively. In all groups of NET patients, CgA proved to be more sensitive than NSE. NSE and CgA had a specificity of 73% and 68% respectively. Immunostaining for NSE was positive in three out of eight controls with elevated CgA levels, whereas immunostaining for CgA and synaptophysin was negative in all cases. Elevated CgA levels were significantly associated with two independent parameters, namely the presence of other secretions (P = 0.0001) and a heavy tumour burden (P = 0.001). Elevated NSE levels were exclusively associated with poor tumour differentiation (P = 0.01). Among six patients with NET followed for 11-37 months, CgA appeared to be a better marker of tumour evolution than NSE. We suggest that CgA ought to be the only general marker screened in NET patients.

Cytotoxic therapy with etoposide and cisplatin in advanced adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a rare tumour with a poor prognosis. Cisplatin is the most widely tested cytotoxic agent in this disease. A total of 18 patients with advanced ACC were enrolled. Cytotoxic therapy consisted of etoposide (VP16) (100 mg m(-2) day(-1) on days 1-3) and cisplatin (100 mg m(-2) day(-1) on day 1) every 4 weeks. Mitotane treatment was maintained during chemotherapy in 14 patients. A complete response was observed in three cases and a partial response in three cases, giving an overall response rate of 33%. Tumour response was observed in three of the six patients with progressive disease during treatment with mitotane given at an effective dosage, as shown by serum levels >14 mg l(-1). Toxic effects were as expected and were non-life-threatening; no treatment interruption was required.

Renal function and organic anion and cation transport during dehydration and/or food restriction in chickens

The effect of dehydration in the presence or absence of continued food intake on renal function was evaluated in chickens. In addition, renal transport of organic anions and cations under these conditions was assessed in vitro by uptake of 14C-para-aminohippuric acid and 14C-tetraethylammonium bromide by renal slices. Water restriction with continued food intake resulted in increases in serum osmolality and serum concentrations of sodium, uric acid, calcium and total protein. If food was restricted in addition to water, only serum osmolality and sodium concentration were significantly increased after 48 hours. Dehydration with continued access to food resulted in marked decreases in extracellular fluid volume, glomerular filtration rate and effective renal plasma flow. If food was restricted during dehydration, the decrease in effective renal plasma flow was attenuated despite reductions in glomerular filtration rate and extracellular fluid comparable to that seen in dehydrated birds allowed free access to food. Transport of organic anions was significantly increased after 24 and 48 hours of water restriction, regardless of whether food was withheld. Enhanced transport of organic anions in the presence of decreased glomerular filtration rate and effective renal plasma flow during dehydration may promote precipitation of urates and nephrosis in chickens.

Relevance of estrogen and progesterone receptors enzyme immunoassay in malignant, benign and surrounding normal thyroid tissue

Several authors have demonstrated the presence of estrogen receptors (ER) and progesterone receptors (PR) in thyroid tissue, generally using dextran coated charcoal method (DCCA). The aim of the study was to measure ER and PR in thyroid specimens using an immunoenzymatic method, and to evaluate the meaning of different prevalence of ER and PR in malignant and benign thyroid disease, as compared with normal thyroid tissue. We have measured ER and PR in thyroid tissue from 28 benign and 20 malignant thyroid lesions, and in 38 samples of surrounding normal thyroid tissues. The sensitivity of ER-EIA and PR-EIA was 1.0 and 1.5 fmol/mg protein, respectively. In thyroid carcinoma the frequency of ER positivity (ER+) was 7/20 (35%); it was significantly higher in the surrounding normal tissue (15/20; 71%) (p = 0.03). In benign thyroid disease, the prevalence of ER+ was 11/28 (39%) and in the surrounding normal tissue it was 11/18 (61%) (p = not significant). PR+ was detected in 7/20 (35%) thyroid cancers and in 15/28 (53%) benign lesions without significant difference with the frequency detected in the surrounding normal tissues. ER and PR concentrations (mean +/- SD) in thyroid cancer was 2.2 +/- 2.2 and 2.2 +/- 2.9 respectively, similarly to that detected in benign thyroid disease and in normal tissue. The simultaneous presence of ER and PR (ER+PR+) was also evaluated. We have found that the frequency of ER+ PR+ was significantly higher in benign lesions (8/28; 28.6%) as compared with malignant samples (1/20; 5%) (p < 0.05); the frequency of ER+PR+ was significantly higher in normal tissue surrounding the malignant lesions (9/20; 45) (p = 0.003). Our data indicate i) EIA method is appropriate to detect ER and PR in thyroid tissue. ii) The frequency of ER+ and ER+PR+ specimens is significantly higher in normal thyroid tissue than in pathologic tissues. This indicates that ER and PR immunoassays may be useful tools to evaluate the normal biological activity of thyroid cells.

Relationship between breast cancer and thyroid disease: relevance of autoimmune thyroid disorders in breast malignancy

The relationship between thyroid dysfunction and breast cancer (BC) is debated. To clarify this controversial issue, a prospective study on thyroid function in BC was performed. The prevalence of thyroid disease was examined in 102 consecutive BC patients with ductal infiltrating carcinoma after surgery and before starting any chemohormonal or x-ray therapy and in 100 age-matched control healthy women living in the same borderline iodine-sufficient geographic area. All subjects were submitted to clinical ultrasound thyroid evaluation and serum free T4, free T3, TSH, thyroperoxidase antibody, and thyroglobulin antibody determination. Fine needle aspiration was performed in all thyroid nodules. Estrogen and progesterone receptors (ER and PR, respectively) were assayed in 92 and 55 BC specimens, respectively. The overall prevalence of thyroid disease was 47 in 102 (46%) in BC patients and 14 in 100 (14%) in controls (P < 0.0001). The prevalence of nontoxic goiter was 27.4% in BC patients and 11% in controls (P = 0.003). Hashimoto's thyroiditis was found in 13.7% of BC patients and in only 2% of the controls (P < 0.005). Other thyroid disorders found in the BC group included 2 cases of Graves' disease, 2 of thyroid carcinoma, and 1 of subacute thyroiditis, whereas in the control group only 1 case of Graves' disease and none of the other disorders were found. Mean free T3, free T4, and TSH concentrations showed no difference between BC patients and controls. The prevalence of thyroperoxidase antibody was higher in BC patients than in controls (23.5% vs. 8%; P < 0.005), whereas the prevalence of thyroglobulin antibody was not different. In BC patients the presence of thyroid antibodies was more frequently associated with clinically detectable autoimmune thyroiditis (14 of 26, 51.8%; P = 0.03) and was more common in the younger group. The positivity of ER was found in 51 of 92 (55.43%) and that of PR was found in 26 of 55 (47.27%) BC specimens. No relationship was found among ER, PR status, and the presence of serum thyroid antibodies. In conclusion, 1) the present study provides evidence that the overall prevalence of thyroid disorders is increased in patients with breast cancer, and 2) thyroid autoimmune disorders, especially Hashimoto's thyroiditis, account to a large extent for the increased prevalence of thyroid disease in patients with breast cancer. This feature is independent from the ER and PR status of the primary tumor. The present findings call attention to the usefulness of screening for thyroid disease in any patient with breast cancer.

Detection of Toxoplasma gondii antigen-containing immune complexes in the serum of cats

Enzyme-linked immunosorbent assays for the detection of Toxoplasma gondii antigen-containing IgM immune complexes (T gondii-specific IgM-IC) and IgG immune complexes (T gondii-specific IgG-IC) in the serum of cats were developed. Serum from clinically ill, naturally infected cats; healthy, naturally infected cats; and healthy cats experimentally inoculated with T gondii was assayed. All combinations of T gondii-specific IgM, IgG, antigens, IgM-IC, and IgG-IC were detected in naturally infected and experimentally infected cats. Clinically ill cats and cats with ocular signs of toxoplasmosis were more likely than healthy cats to have T gondii-specific IC in serum. It was concluded that T gondii-specific IC form in the serum of cats, may play a role in clinical disease development, and affect the results of T gondii-specific IgM, IgG, and antigen serologic assays.

Interference of thyroperoxidase on immuno-cytochemical determination of steroid receptors in thyroid tissue

The presence of sexual steroid receptor proteins in thyroid tissue has been previously demonstrated by biochemical means. The aim of this study was to determine the estrogen (ER) and progesterone (PR) receptors in malignant (12 papillary and 1 follicular carcinoma) and nonmalignant (19 multinodular goiters, 1 Graves' disease, 1 Hashimoto's thyroiditis) thyroid diseases using immunocytochemical assay employing monoclonal anti-ER and anti-PR antibodies and the peroxidase-antiperoxidase technique. Positive results were obtained in 24/34 (70%) for ER (ER-ICA+) and 22/34 (64%) for PR (PR-ICA+). To evaluate the possible interference of thyroperoxidase in the immunostaining, in consecutive sections of a positive specimen, primary antibody or primary antibody plus bridging antibody or PAP complex was omitted. Using these modified procedures, staining distribution was similar to that obtained by the standard procedure: in contrast, no staining was found in the positive control, i.e. a breast cancer specimen. The inhibition of the endogenous peroxidase caused a loss of staining in both the standard and modified procedures on thyroid specimens; no staining modification was obtained in the positive control. These results suggest that the staining observed in thyroid tissue is not specific and related to the activity of thyroperoxidase on chromogen solution. The complete loss of staining after peroxidase inhibition appears to be in contrast with the results obtained by biochemical method, and different antigenicity of thyroid receptors in comparison with breast receptors may explain this discrepancy.

Comparison of monoclonal immunocytochemical and immunoenzymatic methods for steroid receptor evaluation in breast cancer

The production of monoclonal antibodies against estrogen receptor (ER) and progesterone receptor (PR) has permitted the development of the enzyme immunoassay (EIA) and immunocytochemical assay (ICA) for steroid receptor determination. The results obtained with these two techniques, using the same monoclonal antibodies, were compared in a large series of breast carcinomas (187 for ER and 100 for PR). The correlation between these methods was significant for ER (rs = 0.54) and PR (rs = 0.55) (P less than 0.001) but was lost when the receptor concentrations determined by EIA were less than or equal to 15 and less than or equal to 30 fmol/mg protein for ER and PR, respectively. When these values are considered as cutoffs, the concordance between the two methods was 84.5% for ER and 73% for PR. An analysis of discordant results revealed that low epithelial cellularity generally was present in ICA-positive, EIA-negative specimens, whereas only focal positivity with ICA, or positivity of only normal peripheral mammary ducts and lobules, frequently was found in ICA-negative, EIA-positive tumors. In conclusion, there is good correlation between the results obtained by EIA and ICA methods for detection of ER and PR. The authors suggest that biochemical and histochemical methods for steroid receptors could be considered complementary and used together for the analysis of breast cancer.