Direct-acting antiviral treatment for hepatitis C virus infection and risk of incident liver cancer: a retrospective cohort study.

BACKGROUND: Eradication of hepatitis C virus (HCV) infection via interferon-based treatment lowers hepatocellular carcinoma risk; some research suggests this effect extends to interferon-free treatment. AIMS: The objective of this retrospective cohort study was to examine the association of direct-acting antiviral (DAA) exposure with risk of incident liver cancer in real-world data. METHODS: From United States administrative claims data through March 31, 2017, we identified 30 183 adult HCV patients exposed to DAAs. For comparison, we identified contemporary adult HCV patients without evidence of HCV treatment (N = 137 502), and historical HCV patients treated with interferon prior to the introduction of DAAs (N = 12 948). Included patients had at least 12 months of prior enrolment and no evidence of prior liver cancer at baseline. Hazard ratios (HRs) estimating risk of incident liver cancer associated with DAA treatment were calculated using Cox proportional hazards methods. RESULTS: Relative to untreated HCV patients, DAA-treated patients were older, more likely to be male, and more likely to have cirrhosis at baseline. After adjustment, DAA treatment was associated with a significantly reduced risk of liver cancer relative to no treatment (adjusted HR = 0.84, 95% CI: 0.73-0.96), and relative to interferon-based treatment in the pre-DAA era (HR = 0.69, 95% CI: 0.59-0.81). CONCLUSIONS: In this large, population-based study, DAA-based treatment was associated with a reduced risk of incident liver cancer relative to both no HCV treatment and to interferon-based treatment in the pre-DAA era. As additional follow-up time of DAA-treated patients accrues, we anticipate that the long-term benefits of DAA treatment will become more apparent.

Genetic risk and longitudinal disease activity in systemic lupus erythematosus using targeted maximum likelihood estimation.

Systemic lupus erythematous (SLE) is a chronic autoimmune disease associated with genetic and environmental risk factors. However, the extent to which genetic risk is causally associated with disease activity is unknown. We utilized longitudinal-targeted maximum likelihood estimation to estimate the causal association between a genetic risk score (GRS) comprising 41 established SLE variants and clinically important disease activity as measured by the validated Systemic Lupus Activity Questionnaire (SLAQ) in a multiethnic cohort of 942 individuals with SLE. We did not find evidence of a clinically important SLAQ score difference (>4.0) for individuals with a high GRS compared with those with a low GRS across nine time points after controlling for sex, ancestry, renal status, dialysis, disease duration, treatment, depression, smoking and education, as well as time-dependent confounding of missing visits. Individual single-nucleotide polymorphism (SNP) analyses revealed that 12 of the 41 variants were significantly associated with clinically relevant changes in SLAQ scores across time points eight and nine after controlling for multiple testing. Results based on sophisticated causal modeling of longitudinal data in a large patient cohort suggest that individual SLE risk variants may influence disease activity over time. Our findings also emphasize a role for other biological or environmental factors.

Effects of caging type and animal source on the development of foot lesions in Sprague Dawley rats (Rattus norvegicus).

Retrospective analysis of data from a chronic (2-year) rat (Rattus norvegicus) carcinogenicity study was performed to compare the incidence of foot lesion development relative to cage type and animal supplier. Groups of rats from two different suppliers were housed in wire-bottom or polycarbonate cages. Clinical observations and body weights were collected. Data were analyzed to determine foot lesion occurrence, time to onset of foot lesions, and body weight change over time. Noteworthy abnormalities of the plantar surface of the hind foot (i.e., ulcers or nodular swellings) were more common in heavier rats than in lighter animals of the same sex (but different source), and abnormalities were more common in rats housed in wire cages than polycarbonate cages. However, despite differences in weight, cage type, and supplier, lesions were not found until the rats had been housed for more than 1 year.

Inhalation toxicity of potassium octatitanate fibers (TISMO) in rats following 13 weeks of aerosol exposure.

One hundred and forty male and 140 female rats were divided into 1 control and 3 test groups of 35 rats each, per sex, and exposed by whole-body inhalation to test compound at target concentrations of 0, 1 mg/m(3) (1700 fibers/cm(3), 123 WHO fibers/cm(3)), 10 mg/m(3) (5900 fibers/cm(3), 952 WHO fibers/cm(3)), and 100 mg/m(3) (112,700 fibers/cm(3), 7440 WHO fibers/cm(3)) for 6 h/day, 5 days/wk for 13 wk. Ten rats from each group were killed after 13 wk of exposure and 13 wk of recovery, respectively, for histopathological evaluation. The other 15 rats from each group were killed to study lung clearance after 91 days of exposure, and approximately 1.5 and 3 mo of recovery following the end of the 13 wk of exposure. The mean fiber length of the chamber atmosphere was 2.8, 2.7, and 2.8 microm, while the mean fiber width was 0.48, 0.48, and 0.45 microm for the 1-, 10-, and 100-mg/m(3) chambers, respectively. In the 1-mg/m(3) (123 WHO fibers/cm(3)) exposure group, inhaled particles were mostly retained in a few fiber-laden alveolar macrophages (AMs) within the alveoli adjacent to alveolar ducts without any adverse tissue response throughout 13 wk of exposure and following 13 wk of recovery. This exposure concentration was considered to be a no-observable-adverse-effect level (NOAEL), since the alveoli containing fiber-laden AMs preserved normal structure. After 13 wk of exposure to 10 mg/m(3) (952 WHO fibers/cm(3)), fiber-laden AMs were mainly retained at the alveoli adjacent to the alveolar ducts. Infrequently, slight fibrotic thickening was observed in the alveolar ducts and adjoining alveoli, with proliferating fibroblasts and hyperplastic Type II pneumocytes, and microgranulomas. Occasionally, trace amounts of collagenous material were deposited in the thickened alveolar ducts and adjoining alveolar walls. In addition, minimal alveolar bronchiolarization was occasionally found in the alveoli adjacent to the terminal bronchioles. The peribronchial lymphoid tissue and thymic lymph nodes contained migrated fiber-laden AMs. After 13 wk of recovery, fiber-laden AMs had mostly disappeared from alveoli located in the peripheral acini, but they localized in the alveolar ducts region, suggesting there was active lung clearance of fibers by the AMs via airways. Thickened alveolar ducts and adjacent alveoli were decreased in thickness, a reversible change manifested by reduction of proliferating Type II pneumocytes and fibroblasts. Collagenized fibrosis was slightly more pronounced in the thickened alveolar ducts and adjoining alveoli. The lung response following 13 wk of exposure to 100 mg/m(3) (7440 WHO fibers/cm(3)) and after 13 wk of recovery was similar to those findings of the 952 WHO fibers/cm(3) group but more pronounced, demonstrating a clear concentration-related response. Alveolar ducts and adjoining alveolar walls in the central acini were irregularly thickened with more frequent evidence of minimal collagenized fibrosis. The lung burden and clearance of fibers were estimated by measuring the total content of titanium (Ti) in the lungs, but high variability of Ti content in control and exposed groups prevented meaningful lung clearance analysis.

An assessment of neurotoxicity of aroclors 1016, 1242, 1254, and 1260 administered in diet to Sprague-Dawley rats for one year.

As part of a comparative chronic toxicity/oncogenicity study of different Aroclors (1016, 1242, 1254, and 1260), neurotoxicity was assessed in male and female Sprague-Dawley rats using functional observational battery (FOB) and motor activity tests, and histopathologic evaluation of selected nervous system tissues. Doses varied by Aroclor and ranged from 25 to 200 ppm in the diet. Animals were evaluated prior to initiation of dosing and at 13, 26, 39, and 52 weeks of exposure. Clinical signs, body weights, and feed consumption were evaluated weekly. Data analysis of FOB and motor activity results revealed several instances where Aroclor-treated groups were different from control. However, these were considered incidental, as they lacked any consistent dose- or time-related pattern that would suggest Aroclor-induced neurotoxicity. The nonremarkable findings during each of the four assessments were supported by the absence of any treatment-related clinical signs or mortality. Decreased body weight gain was evident in the male 100 ppm Aroclor 1254 dose group and in all female Aroclor 1254 dose groups late in the study (when a linear relationship was assumed between body weight and time), correlating with decreased feed consumption. Although a variety of incidental, spontaneous, degenerative changes were found in nervous tissue evaluated histopathologically, these changes were seen with similar incidence and severity in treated and control groups. No lesions were found that could be attributed to Aroclor-related neurotoxicity. In summary, 52 weeks of exposure to Aroclors 1016, 1242, 1254, or 1260 mixed in the diet did not yield any functional or morphologic changes indicative of PCB-induced neurotoxicity.

Therapeutic approaches to dermatotoxicity by sulfur mustard. I. Modulaton of sulfur mustard-induced cutaneous injury in the mouse ear vesicant model.

The mouse ear edema model is recognized for its usefulness in studying skin responses and damage following exposure to chemical irritants, and for evaluating pharmacological agents against chemically induced skin injury. We recently modified the mouse ear edema model for use with sulfur mustard (HD) and used this model to study the protective effect of 33 topically applied compounds comprising five pharmaceutical strategies (anti-inflammatories, protease inhibitors, scavengers/chelators, poly(ADP-ribose) polymerase (PARP) inhibitors, calcium modulators/chelators) against HD-induced dermatotoxicity. Pharmacological modulation of HD injury in mouse ears was established by a reduction in edema or histopathology (epidermal necrosis and epidermal-dermal separation) at 24 h following topical liquid HD exposure. Ten of the 33 compounds administered as single topical pretreatments up to 2 h prior to HD challenge produced significant reductions in edema. Five of these ten also produced significant reductions in histological endpoints. Three candidates (olvanil, indomethacin, hydrocortisone) showing protection at 24 h were evaluated further for 'extended protection' at 48 and 72 h after HD challenge and showed significant modulation of edema at 48 h but not at 72 h. Olvanil also showed significant reductions in histology at 48 and 72 h. Olvanil and indomethacin were shown to reduce significantly the edema at 24 h post-exposure when administered topically 10 min after HD challenge, with olvanil additionally protecting against epidermal necrosis. These results demonstrate prophylactic and treatment effects of pharmacological agents against HD-induced skin injury in an in vivo model and support the continued use of the mouse ear vesicant model (MEVM) for evaluating medical countermeasures against HD.

Sulfur mustard-induced skin burns in weanling swine evaluated clinically and histopathologically.

Histopathological indicators and clinical observations were used to evaluate wound severity, depth and degree of healing on days 2 and 8 for full-skin-thickness sulfur-mustard (HD)-induced burns in weanling swine. Six female weanling swine were exposed for 2 h to 400 microl of HD at each of six dose sites on the hairless abdominal skin. Biopsy samples (8 mm) were taken from the periphery and from the center of the wound on day 2, and the wound was excised on day 8. Histopathological indicators evaluated were epidermal necrosis, follicular necrosis, dermal necrosis, vascular necrosis, depth of injury, ulceration (loss of epidermis), granulation tissue response, neovascularization, re-epithelialization (hyperplasia) and completeness of healing. Wounds were more severe from anterior to posterior. Histopathological assessment of epidermal ulceration and necrosis of epidermis, dermis, basal epithelium, adnexal structures and subcutaneous tissue were useful indicators of wound development on day 2. Granulation tissue response (observed as early as day 8) and re-epithelialization were good indicators of wound healing. Clinical evaluations were performed on day 2 prior to and after debriding, and on study day 8. Clinical observations on study day 2 were for wound size and for exudation, erythema, edema, necrosis and eschar. Clinical observations on study day 8 were for the previous parameters and for re-epithelialization, granulation and infection. Wound size and severity increased from anterior to posterior position. Size, exudation and edema were useful indicators of wound development. These histological and clinical observation parameters will be used in future experiments to compare various treatments for HD-induced burns.

Evaluation of neutralized chemical agent identification sets (CAIS) for skin injury with an overview of the vesicant potential of agent degradation products.

Vesication and skin irritation studies were conducted in hairless guinea-pigs to determine the vesicant and skin irritation potential of chemically-neutralized Chemical Agent Identification Sets (CAIS). The CAIS are training items that contain chemical warfare-related material--sulfur mustard (HD), nitrogen mustard (HN) or lewisite (L)--and were declared obsolete in 1971. Animals were dosed topically with 'test article'--neat HD, 10% agent/chloroform solutions or product solutions (waste-streams) from neutralized CAIS--and evaluated for skin-damaging effects (gross and microscopic). Product solutions from the chemical neutralization of neat sulfur mustard resulted in microvesicle formation. All agent-dosed (HD or agent/chloroform solutions) sites manifested microblisters as well as other histopathological lesions of the skin. Waste-streams from the neutralization of agent (agent/chloroform or agent/charcoal) were devoid of vesicant activity. Cutaneous effects (erythema and edema) were consistent with the skin-injurious activity associated with the neutralizing reagent 1,3-dichloro-5,5-dimethylhydantoin (DCDMH). Chemical neutralization of CAIS was effective in eliminating/reducing the vesicant property of CAIS containing agent in chloroform or agent on charcoal but was inefficient in reducing the vesicant potential of CAIS containing neat sulfur mustard.

Comparative carcinogenicity in Sprague-Dawley rats of the polychlorinated biphenyl mixtures Aroclors 1016, 1242, 1254, and 1260.

A comprehensive chronic toxicity and carcinogenicity study was conducted on a series of Aroclors (1016, 1242, 1254, and 1260). Each Aroclor was assessed at multiple dietary concentrations, ranging from 25 to 200 ppm, for 24 months in male and female Sprague-Dawley rats. Liver toxicity was indicated by elevated serum enzyme activity (AST, ALT, and GGT), elevated serum cholesterol concentration, decreases in hematologic parameters (RBC, Hb, and Hct), hepatocellular hypertrophy, an increased incidence of altered hepatocellular foci, and an increased incidence of hepatocellular neoplasms (primarily adenomas). Liver toxicity was distinctly more severe in females than in males. The incidence of hepatocellular neoplasms was highly sex-dependent (females >> males), differed between Aroclor mixtures and, for females, increased with dose and followed the general incidence pattern of Aroclor 1254 > Aroclor 1260 approximately Aroclor 1242 > Aroclor 1016. A significant response (p < 0.05) in males was seen only for the high dose of Aroclor 1260. A small increase in the incidence of thyroid gland follicular cell adenomas was noted in males for Aroclors 1242, 1254, and 1260, with the incidence being uniform across dose groups and Aroclor mixtures. For females, increased survival relative to controls was observed for all Aroclor treatment groups. A significantly decreased trend in the incidence of mammary gland neoplasms compared to control was also noted for females receiving Aroclors 1242, 1254, and 1260.

13-week inhalation toxicity study of dimethylformamide (DMF) in cynomolgus monkeys.

This study was conducted to assess the subchronic inhalation toxicity of dimethylformamide (DMF) in the cynomolgus monkey. Particular attention was paid to the liver since DMF has been shown to produce liver damage in rodents, dogs, and humans. Groups of three cynomolgus monkeys/sex/group received whole-body exposures for 6 hr/day, 5 days/week for 13 weeks to 0, 30, 100, or 500 ppm DMF. Evaluations for toxicity included body and organ weights, clinical observations, hematology, serum chemistry, urinalysis, and gross and microscopic examinations. Clinical laboratory evaluations were conducted twice prior to the start of the study at exposure weeks 2, 4, 8, and 12 and at necropsy. Semen, collected from male monkeys three times prior to the start of the study and weekly during the course of the study, was analyzed for sample volume, sperm count, motility, and morphology. In addition, daily vaginal swabs were obtained from all females prior to exposure to determine mean menses cycle length. Although there was a slight trend toward increased cycle length, this trend could not be definitely attributed to compound exposure. Based on extensive monitoring of the monkeys' clinical condition, semen quantity and quality, and clinical and pathological evaluations, no exposure-related adverse health effects were detected following exposure to concentrations of DMF ranging from 30 to 500 ppm for 13 weeks.

Relationship of pharmacokinetics and drug distribution in tissue to increased safety of amphotericin B colloidal dispersion in dogs.

The safety, pharmacokinetics, and distribution in tissue of an amphotericin B (AmB)-cholesteryl sulfate colloidal dispersion (ABCD) were compared with those of micellar amphotericin B-deoxycholate (m-AmB). Dogs received 14 daily injections of ABCD (0.6 to 10 mg/kg of body weight per day) or m-AmB (0.6 mg/kg/day). Safety was evaluated by monitoring body weight, hematology, clinical chemistry, and urinalysis during the study and by microscopic examination of tissues at the time of necropsy (day 16). AmB concentrations in plasma were measured in some groups on days 1, 7, and 14 and in necropsy tissue samples. ABCD produced a spectrum of toxic effects in the kidneys, gut, and liver similar to those of m-AmB, but ABCD was eightfold safer than m-AmB. The highest tolerated dose of ABCD (5.0 mg/kg/day) produced effects similar to those of m-AmB (0.6 mg/kg/day). ABCD produced lower concentrations in plasma than an equal dose of m-AmB did. Clearances on days 7 and 14 were higher for ABCD (304 and 295 ml/h.kg) than they were for m-AmB (67 and 53 ml/h.kg). Concentrations in plasma reached steady state after ABCD administration, but they increased after repeated dosing with m-AmB. Diurnal fluctuations in AmB concentrations in plasma were observed 4 to 8 h after the time of dosing. ABCD resulted in lower AmB concentrations in tissue than m-AmB did, except in the reticuloendothelial system. Up to 90% of AmB administered as ABCD was recovered from the liver and spleen on day 16. Reduced drug levels in the kidneys and gut correlated with reduced indications of toxicity in these organs after ABCD administration. Although ABCD increased concentrations of AmB in the reticuloendothelial system, increased toxicity was not observed in these organs.

A 90-day inhalation toxicity study with benomyl in rats.

Benomyl [methyl 1-(butylcarbamoyl)-2-benzimidazolecarbamate, CAS Registry No. 17804-35-2] is a fungicide and the possibility for inhalation exposure exists for field workers. To assess the toxicity of benomyl, groups of 20 male and 20 female CD rats were exposed nose-only 6 hr a day, 5 days a week, to concentrations of 0, 10, 50 or 200 mg/m3 of a benomyl atmosphere. At the midpoint (approximately 45 days on test) and at the end of the exposure period, blood and urine samples for clinical evaluation were collected from 10 rats/group/sex, and these animals were sacrificed for pathological examination. Similar evaluations were performed on all remaining rats at the end of the 90-day test period. After approximately 45 days on test, compound-related degeneration of the olfactory epithelium was observed in all males and in 8 of 10 female rats exposed to 200 mg/m3 benomyl. Two male rats exposed to 50 mg/m3 had similar, although less severe, areas of olfactory epithelial degeneration. After approximately 90 days of exposure, the remaining 10 rats/group/sex were sacrificed and examined. Of these rats, all of the males and females exposed to 200 mg/m3 had olfactory degeneration, along with 3 males exposed to 50 mg/m3 of benomyl. No other observed lesions were interpreted to have been caused by the benomyl exposure. In addition, male rats exposed to 200 mg/m3 benomyl had depressed mean body weights compared to controls and this finding correlated with a reduction in food consumption. Based on pathological observations, 10 mg/m3 represents the no-observable-effect level (NOEL) for the male rats, and 50 mg/m3 is the NOEL for the female rats.

Cardiomyopathy in Soman and Sarin intoxicated rats.

Rats surviving various single dose of the organophosphorus anticholinesterase nerve agents Soman and Sarin were examined by light microscopy at intervals up to 35 days post-exposure. Brain lesions, identical to those that have been reported elsewhere were present, as well as a previously unreported finding associated with Soman or Sarin intoxication: half of all animals that had brain lesions also had areas of myocardial degeneration and necrosis. Depending upon the point in time at which cardiac tissues were examined, findings varied from areas of acute myolysis and necrosis to areas undergoing resolution of damage. The finding of brain lesions in those animals having cardiac lesions suggests a relationship between the convulsion induced neurologic and cardiac lesions. These studies suggest that convulsive doses of chemical warfare agents induce pathological changes in the cardiovascular system of laboratory animals.

Acute neuropathology in soman poisoned rats.

Groups of rats received single subcutaneous injections of the highly toxic organophosphate compound, soman, in doses of 106, 133 or 165 micrograms/kg and were observed during the acute phase of intoxication. Survivors were killed at intervals up to fourteen days after exposure, and brain sections were examined by light microscopy. A consistent pattern of neuronal degeneration and necrosis was observed in brains of animals which had experienced convulsions during the intoxication. The lesions had an appearance and distribution similar to that reported for both hypoxic injury and status epilepticus. No lesions were observed in animals which did not experience convulsions. The results indicate that soman, and possibly other similar organophosphate compounds, may produce significant irreversible damage to the central nervous system.