Immersive virtual reality fitness games for enhancement of recovery after colorectal surgery: study protocol for a randomised pilot trial.

BACKGROUND: Physical inactivity after surgery is an important risk factor for postoperative complications. Compared to conventional physiotherapy, activity-promoting video games are often more motivating and engaging for patients with physical impairments. This effect could be enhanced by immersive virtual reality (VR) applications that visually, aurally and haptically simulate a virtual environment and provide a more interactive experience. The use of VR-based fitness games in the early postoperative phase could contribute to improved mobilisation and have beneficial psychological effects. Currently, there is no data on the use of VR-based fitness games in the early postoperative period after colorectal surgery. METHODS: This pilot trial features a single-centre, randomised, two-arm study design with a 1:1 allocation. Patients undergoing elective abdominal surgery for colorectal cancer or liver metastases of colorectal cancer will be recruited. Participants will be randomly assigned to an intervention group or a control group. Patients randomised to the intervention group will perform immersive virtual reality-based fitness exercises during their postoperative hospital stay. Feasibility and clinical outcomes will be assessed. DISCUSSION: Early mobilisation after surgery is crucial for reducing many postoperative complications. VR-based interventions are easy to use and often inexpensive, especially compared to interventions that require more medical staff and equipment. VR-based interventions could serve as an alternative or complement to regular physiotherapy and enhance mobilisation after surgery. The proposed pilot study will be the first step to evaluate the feasibility of VR-based interventions in the perioperative period, with the aim of improving the postoperative rehabilitation of cancer patients. TRIAL REGISTRATION: The trial has been registered in the German Clinical Trials Register (DRKS) Nr. DRKS00024888 , on April 13, 2021, WHO Universal Trial Number (UTN) U1111-1261-5968.

Intraoperative endoluminal pyloromyotomy for reduction of delayed gastric emptying after pylorus preserving partial pancreaticoduodenectomy (PORRIDGE trial): study protocol for a randomised controlled trial.

BACKGROUND: Pylorus-preserving pancreaticoduodenectomy (ppPD) is a standard surgical procedure for the treatment of resectable neoplasms of the periampullary region. One of the most common postoperative complications after ppPD is delayed gastric emptying (DGE) which reduces quality of life, prevents a timely return to a solid oral diet and prolongs the length of hospital stay. In a retrospective analysis, intraoperative endoluminal pyloromyotomy was associated with a reduced rate of DGE. The aim of this study is to investigate the effect of intraoperative endoluminal pyloromyotomy on postoperative DGE after ppPD in a randomised and controlled setting. METHODS: This randomised trial features parallel group design with a 1:1 allocation ratio and a superiority hypothesis. Patients with a minimum age of 18 years and an indication for ppPD are eligible to participate in this study and will be randomised intraoperatively to receive either endoluminal pyloromyotomy or atraumatic stretching of the pylorus. The sample size calculation (n=64 per study arm) is based on retrospective data. The primary endpoint is the rate of DGE within 30 days. Secondary endpoints are quality of life, operation time, estimated blood loss, length of hospital stay, morbidity and mortality. DISCUSSION: DGE after ppPD is a common complication with an incomplete understood aetiology. Prevention of DGE could improve outcomes and enhance quality of life after one of the most common procedures in pancreatic surgery. This trial will expand the existing evidence on intraoperative pyloromyotomy, and the results will provide additional data on a simple surgical technique that could reduce the incidence of postoperative DGE. TRIAL REGISTRATION: German Clinical Trials Register DRKS00013503 . Registered on 27 December 2017.

Intraoperative endoluminal pyloromyotomy as a novel approach to reduce delayed gastric emptying after pylorus-preserving pancreaticoduodenectomy-a retrospective study.

BACKGROUND: Delayed gastric emptying (DGE) is one of the most common complications after pylorus-preserving partial pancreaticoduodenectomy (ppPD). The aim of this retrospective study was to assess whether an intraoperative pyloromyotomy during ppPD prior to the creation of duodenojejunostomy reduces DGE. METHODS: Patients who underwent pylorus-preserving pancreaticoduodenectomy between January 2015 and December 2017 were divided into two groups on the basis of whether an intraoperative pyloromyotomy was performed (pyloromyotomy (PM) group) or not (no pyloromyotomy (NP) group). The primary endpoint was DGE according to the ISGPS definition. The confirmatory analysis of the primary endpoint was performed with multivariate analysis. RESULTS: One hundred and ten patients were included in the statistical analysis. Pyloromyotomy was performed in 44 of 110 (40%) cases. DGE of any grade was present in 62 patients (56.4%). The DGE rate was lower in the PM group (40.9%) compared with the NP group (66.7%), and pyloromyotomy was associated with a reduced risk for DGE in univariate (OR 0.35, 95% CI 0.16-0.76; P = 0.008) and multivariate analyses (OR 0.32, 95% CI 0.13-0.77; P = 0.011). The presence of an intra-abdominal complication was an independent risk factor for DGE in the multivariate analysis (OR 5.54, 95% CI 2.00-15.36; P = 0.001). CONCLUSION: Intraoperative endoluminal pyloromyotomy during ppPD was associated with a reduced risk for DGE in this retrospective study. Pyloromyotomy should be considered a simple technique that can potentially reduce DGE rates after ppPD.

Optimizing COVID-19 surveillance in long-term care facilities: a modelling study.

BACKGROUND: Long-term care facilities (LTCFs) are vulnerable to outbreaks of coronavirus disease 2019 (COVID-19). Timely epidemiological surveillance is essential for outbreak response, but is complicated by a high proportion of silent (non-symptomatic) infections and limited testing resources. METHODS: We used a stochastic, individual-based model to simulate transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) along detailed inter-individual contact networks describing patient-staff interactions in a real LTCF setting. We simulated distribution of nasopharyngeal swabs and reverse transcriptase polymerase chain reaction (RT-PCR) tests using clinical and demographic indications and evaluated the efficacy and resource-efficiency of a range of surveillance strategies, including group testing (sample pooling) and testing cascades, which couple (i) testing for multiple indications (symptoms, admission) with (ii) random daily testing. RESULTS: In the baseline scenario, randomly introducing a silent SARS-CoV-2 infection into a 170-bed LTCF led to large outbreaks, with a cumulative 86 (95% uncertainty interval 6-224) infections after 3 weeks of unmitigated transmission. Efficacy of symptom-based screening was limited by lags to symptom onset and silent asymptomatic and pre-symptomatic transmission. Across scenarios, testing upon admission detected just 34-66% of patients infected upon LTCF entry, and also missed potential introductions from staff. Random daily testing was more effective when targeting patients than staff, but was overall an inefficient use of limited resources. At high testing capacity (> 10 tests/100 beds/day), cascades were most effective, with a 19-36% probability of detecting outbreaks prior to any nosocomial transmission, and 26-46% prior to first onset of COVID-19 symptoms. Conversely, at low capacity (< 2 tests/100 beds/day), group testing strategies detected outbreaks earliest. Pooling randomly selected patients in a daily group test was most likely to detect outbreaks prior to first symptom onset (16-27%), while pooling patients and staff expressing any COVID-like symptoms was the most efficient means to improve surveillance given resource limitations, compared to the reference requiring only 6-9 additional tests and 11-28 additional swabs to detect outbreaks 1-6 days earlier, prior to an additional 11-22 infections. CONCLUSIONS: COVID-19 surveillance is challenged by delayed or absent clinical symptoms and imperfect diagnostic sensitivity of standard RT-PCR tests. In our analysis, group testing was the most effective and efficient COVID-19 surveillance strategy for resource-limited LTCFs. Testing cascades were even more effective given ample testing resources. Increasing testing capacity and updating surveillance protocols accordingly could facilitate earlier detection of emerging outbreaks, informing a need for urgent intervention in settings with ongoing nosocomial transmission.

Electronic Cigarette Use Among College Students: Links to Gender, Race/Ethnicity, Smoking, and Heavy Drinking.

OBJECTIVE: Electronic cigarette (e-cigarette) use continues to rise, and current data regarding use of e-cigarettes among college students are needed. The purpose of this study was to examine e-cigarette use and the relation of such use with gender, race/ethnicity, traditional tobacco use, and heavy drinking. PARTICIPANTS AND METHODS: A sample of 599 college students enrolled in General Psychology at a state university completed a self-report questionnaire. RESULTS: Twenty-nine percent of students reported prior use of e-cigarettes, with 14% reporting use in the past 30 days. E-cigarette use was linked to male gender but not to race/ethnicity. Dual use (ie, concurrent use of both traditional and e-cigarettes) was related to heavier use of traditional and e-cigarettes, and nicotine use was linked to pronounced rates of heavy drinking. CONCLUSIONS: E-cigarette use among college students is exponentially on the rise, and its co-use with alcohol may contribute to negative outcomes in this population.

Bioorthogonal mimetics of palmitoyl-CoA and myristoyl-CoA and their subsequent isolation by click chemistry and characterization by mass spectrometry reveal novel acylated host-proteins modified by HIV-1 infection.

Protein acylation plays a critical role in protein localization and function. Acylation is essential for human immunodeficiency virus 1 (HIV-1) assembly and budding of HIV-1 from the plasma membrane in lipid raft microdomains and is mediated by myristoylation of the Gag polyprotein and the copackaging of the envelope protein is facilitated by colocalization mediated by palmitoylation. Since the viral accessory protein NEF has been shown to alter the substrate specificity of myristoyl transferases, and alter cargo trafficking lipid rafts, we hypothesized that HIV-1 infection may alter protein acylation globally. To test this hypothesis, we labeled HIV-1 infected cells with biomimetics of acyl azides, which are incorporated in a manner analogous to natural acyl-Co-A. A terminal azide group allowed us to use a copper catalyzed click chemistry to conjugate the incorporated modifications to a number of substrates to carry out SDS-PAGE, fluorescence microscopy, and enrichment for LC-MS/MS. Using LC-MS/MS, we identified 103 and 174 proteins from the myristic and palmitic azide enrichments, with 27 and 45 proteins respectively that differentiated HIV-1 infected from uninfected cells. This approach has provided us with important insights into HIV-1 biology and is widely applicable to many virological systems.

Interleukin-6 mediated upregulation of CYP1B1 and CYP2E1 in colorectal cancer involves DNA methylation, miR27b and STAT3.

BACKGROUND: The pro-inflammatory cytokine interleukin-6 (IL6) promotes colorectal cancer (CRC) development. It is also known to regulate cytochrome P450 (CYP450) enzymes, which are involved in CRC tumour initiation and promotion via activation of chemical carcinogens. Here, IL6 regulation of CYP450 expression was investigated in CRC. METHODS: The effect of IL6 on CYP 1A1, 1B1 and 2E1 expression was determined in vitro using CRC cell lines HCT116 and SW480, and CYP450 expression was determined by immunohistochemistry in CRC tissues previously shown to have increased levels of IL6. RESULTS: In mechanistic studies, IL6 treatment significantly induced CYP1B1 and CYP2E1, but not CYP1A1, gene expression in HCT116 and SW480 cells. CYP2E1 expression regulation occurred via a transcriptional mechanism involving STAT3. For CYP1B1 regulation, IL6 downregulated the CYP1B1-targeting microRNA miR27b through a mechanism involving DNA methylation. In clinical samples, the expression of CYP1B1 and CYP2E1, but not CYP1A1, was significantly increased in malignant tissue overexpressing IL6 compared with matched adjacent normal tissue. CONCLUSIONS: Colonic inflammation with the presence of IL6 associated with neoplastic tissue can alter metabolic competency of epithelial cells by manipulating CYP2E1 and CYP1B1 expression through transcriptional and epigenetic mechanisms. This can lead to increased activation of dietary carcinogens and DNA damage, thus promoting colorectal carcinogenesis.

Methods used to quit smoking by people with physical disabilities.

PURPOSE/OBJECTIVE: People with mobility impairments (MIs) have higher smoking rates than the general population. We evaluated the use of psychosocial and pharmacological methods to quit smoking and readiness to quit smoking in this population in a cross-sectional study. RESEARCH METHOD/DESIGN: Current and former smokers with MIs who needed equipment to ambulate (e.g., cane, wheelchair; n = 152, 53.3% female, 86.2% current smokers) were recruited from the community and interviewed by telephone regarding their lifetime use of various quit methods and readiness to quit smoking. RESULTS: Results indicated that 57.3% reported a quit attempt in the past year, and 62% and 88.4% were planning on quitting in the next 30 days and six months, respectively. A minority of smokers with MIs reported using any type of counseling (5.3%; 3.3% in-person counseling and 2.6% phone counseling) or tablet medication (8.6%); 75% had made a "cold turkey" quit attempt (e.g., without any assistance). 36.8% and 19.7% reported using the nicotine patch and gum, respectively. Regression analyses indicated that greater nicotine dependence was associated with lower use of psychosocial treatments (p < .05), greater education was associated with greater tablet medication use (p = .051), and higher income was associated with both greater nicotine replacement therapy (NRT) and tablet medication use (p < .05). Minorities with MIs were significantly less likely to use NRT than non-Hispanic Whites (p < .05). CONCLUSIONS: Individuals with MIs are motivated to quit smoking but underuse some empirically validated cessation treatment options.

Data maximization by multipass analysis of protein mass spectra.

With the proliferation of search engines for the analysis of MS data, multisearch techniques aimed at boosting the discriminating power of the search engines' score functions have recently become popular. Much statistical and algorithmic work has been done, therefore, in order to be able to combine and parse multiple search streams. However, multisearch techniques suffer from long run times, and may have little impact on false negatives because of similar peptide filtering heuristics between searches. This review focuses, rather, on multipass techniques, which use the results of one search to guide the selection of spectra, parameters and sequences in subsequent searches. This reduces the number of false-negative peptide identifications due to peptide candidate filtering while preserving statistical significance of existing (correct) identifications. Furthermore, this technique avoids substantial increases in running time and, by limiting the search space, does not reduce the statistical significance of correct identifications or introduce a statistically significant number of false-positive identifications. However, we argue that the existing combiner tools are not reliably applicable to these multipass situations, because of algorithmic assumptions about search space and statistical assumptions about the rate of true positives. Here we provide an overview of the advantages of and issues in multipass analysis techniques, the existing methods and workflows available to proteomic researchers, and the unsolved statistical and algorithmic issues amenable to future research.

Two-dimensional gel-based approaches for the assessment of N-Linked and O-GlcNAc glycosylation in human and simian immunodeficiency viruses.

The glycosylation state of envelope glycoproteins in human and simian immunodeficiency viruses (HIV/SIV) is critical to viral infectivity and tropism, viral protein processing, and in virus evasion of the immune system. Using a rapid fluorescent 2-D gel-based method coupled with enzymatic pre-treatment of virus with PNGase F (Peptide: N-Glycosidase F) and fluorescent 2-D gels or 2-D gel Western blotting, we show significant differences in the glycosylation patterns of two SIV strains widely used in animal models of HIV disease and vaccine studies. We also demonstrate the modification of a host protein important in HIV biology (HLA-DR) by O-GlcNAc. Further, this experimental pipeline allows for the identification of the modified protein and the site of N-linked glycosylation by fluorescent 2-DE coupled with MS and the qualitative and semi-quantitative assessment of viral glycosylation. The method is fully compatible with downstream glycomics analysis. This approach will permit correlation of virus glycosylation status with pathological severity and may serve as a rapid screen of viruses from physiological samples for further study by more advanced MS methodology.

The role of impulsivity on smoking maintenance.

In order to better understand why those higher in impulsivity experience more difficulties during smoking abstinence, the current study examined the possible mechanisms contributing to cigarette smoking relapse. Fifty dependent cigarette smokers completed measures designed to assess craving, tobacco withdrawal severity, and negative affect during 48 hours of nicotine abstinence. Using a series of multilevel models (SAS Proc Mixed Procedure), significant impulsivity x time analyses revealed differences in craving, F(2, 96) = 3.74, p<.05, and anxiety, F(2, 96) = 3.23, p<.05. Simple slopes analyses indicated that heightened trait-impulsivity predicted greater increases in craving and anxiety during a 48-hour abstinence period. These findings suggest that smokers with higher levels of impulsivity may lack the ability to find an accessible and comparable substitute for cigarette smoking during a cessation attempt. This study also highlights the importance of considering individual differences when treating those who wish to quit smoking.

Impulsivity and the role of smoking-related outcome expectancies among dependent college-aged cigarette smokers.

The relationship between trait-impulsivity and smoking expectancies on smoking progression in undergraduate college students was examined over a 48-hour period of smoking abstinence. Participants were forty-nine college-aged dependent cigarette smokers who completed measures designed to assess impulsivity, nicotine dependence, and smoking expectancies. Using a series of multilevel models, impulsivity by time analyses indicated significant differences in positive reinforcement expectancies, [F (2, 94)=3.19, p<.05], but not in negative reinforcement expectancies, [F (2, 94)=0.49, p=.61]. Simple slopes analyses indicated that heightened trait-impulsivity predicted greater increases in positive reinforcement outcome expectancies at 48 h of abstinence. Level of impulsivity, however, was not related to changes in negative reinforcement expectancies. Results indicate that during an abstinence period, college students higher in trait-impulsivity may be more prone to relapse due to stronger beliefs about the positive effects from smoking a cigarette. These findings highlight the importance of understanding the interaction of personality and cognitive factors when working with young adult smokers wishing to quit this health-compromising behavior.

Quantitative proteomics analysis of human endothelial cell membrane rafts: evidence of MARCKS and MRP regulation in the sphingosine 1-phosphate-induced barrier enhancement.

Endothelial cell barrier dysfunction results in the increased vascular permeability observed in inflammation, tumor metastasis, angiogenesis, and atherosclerosis. Sphingosine 1-phosphate (S1P), a biologically active phosphorylated lipid growth factor released from activated platelets, enhances the endothelial cell barrier integrity in vitro and in vivo. To begin to identify the molecular mechanisms mediating S1P induced endothelial barrier enhancement, quantitative proteomics analysis (iTRAQ) was performed on membrane rafts isolated from human pulmonary artery endothelial cells in the absence or presence of S1P stimulation. Our results demonstrated that S1P mediates rapid and specific recruitment (1 microM, 5 min) of myristoylated alanine-rich protein kinase C substrate (MARCKS) and MARCKS-related protein (MRP) to membrane rafts. Western blot experiments confirmed these findings with both MARCKS and MRP. Finally, small interfering RNA-mediated silencing of MARCKS or MRP or both attenuates S1P-mediated endothelial cell barrier enhancement. These data suggest the regulation of S1P-mediated endothelial cell barrier enhancement via the cell specific localization of MARCKS and MRP and validate the utility of proteomics approaches in the identification of novel molecular targets.

Barrier-to-autointegration factor BAF binds p55 Gag and matrix and is a host component of human immunodeficiency virus type 1 virions.

Barrier-to-autointegration factor (BAF) is a conserved human chromatin protein exploited by retroviruses. Previous investigators showed that BAF binds double-stranded DNA nonspecifically and is a host component of preintegration complexes (PICs) isolated from cells infected with human immunodeficiency virus type 1 (HIV-1) or Moloney murine leukemia virus. BAF protects PIC structure and stimulates the integration of salt-stripped PICs into target DNA in vitro. PICs are thought to acquire BAF from the cytoplasm during infection. However, we identified two human tissues (of 16 tested) in which BAF mRNA was not detected: thymus and peripheral blood leukocytes, which are enriched in CD4(+) T lymphocytes and macrophage precursors, respectively. BAF protein was detected in activated but not resting CD4(+) T lymphocytes; thus, if BAF were essential for PIC function, we hypothesized that virions might "bring their own BAF." Supporting this model, BAF copurified with HIV-1 virions that were digested with subtilisin to remove microvesicle contaminants, and BAF was present in approximately zero to three copies per virion. In three independent assays, BAF bound directly to both p55 Gag (the structural precursor of HIV-1 virions) and its cleaved product, matrix. Using lysates from cells overexpressing Gag, endogenous BAF and Gag were coimmunoprecipitated by antibodies against Gag. Purified recombinant BAF had low micromolar affinities (1.1 to 1.4 micro M) for recombinant Gag and matrix. We conclude that BAF is present at low levels in incoming virions, in addition to being acquired from the cytoplasm of newly infected cells. We further conclude that BAF might contribute to the assembly or activity of HIV-1 PICs through direct binding to matrix, as well as DNA.

Cholesterol depletion of human immunodeficiency virus type 1 and simian immunodeficiency virus with beta-cyclodextrin inactivates and permeabilizes the virions: evidence for virion-associated lipid rafts.

Recent evidence suggests that human immunodeficiency virus type 1 (HIV-1) particles assemble and bud selectively through areas in the plasma membrane of cells that are highly enriched with glycosylphosphatidylinositol-anchored proteins and cholesterol, called lipid rafts. Since cholesterol is required to maintain lipid raft structure and function, we proposed that virion-associated cholesterol removal with the compound 2-hydroxy-propyl-beta-cyclodextrin (beta-CD) might be disruptive to HIV-1 and simian immunodeficiency virus (SIV). We examined the effect of beta-CD on the structure and infectivity of cell-free virions. We found that beta-CD inactivated HIV-1 and SIV in a dose-dependent manner and permeabilized the viral membranes, resulting in the loss of mature Gag proteins (capsid, matrix, nucleocapsid, p1, and p6) without loss of the envelope glycoproteins. SIV also lost reverse transcriptase (RT), integrase (IN), and viral RNA. IN appeared to be only slightly diminished in HIV-1, and viral RNA, RT, matrix, and nucleocapsid proteins were retained in HIV-1 but to a much lesser degree. Host proteins located internally in the virus (actin, moesin, and ezrin) and membrane-associated host proteins (major histocompatibility complex classes I and II) remained associated with the treated virions. Electron microscopy revealed that under conditions that permeabilized the viruses, holes were present in the viral membranes and the viral core structure was perturbed. These data provide evidence that an intact viral membrane is required to maintain mature virion core integrity. Since the viruses were not fixed before beta-CD treatment and intact virion particles were recovered, the data suggest that virions may possess a protein scaffold that can maintain overall structure despite disruptions in membrane integrity.

Ultrasound evaluation of liver disease in cystic fibrosis as part of an annual assessment clinic: a 9-year review.

AIM: To review 9 years of annual assessment data in cystic fibrosis (CF) and evaluate the frequency of hepatobiliary abnormalities and the correlation between ultrasound and biochemical findings. MATERIALS AND METHODS: Over a 9-year period (1990-99), 168 children (age range 1-18 years) with CF have undergone an annual assessment which has included clinical, biochemical and ultrasonographic evaluation of the hepatobiliary system. We have retrospectively reviewed the sequential ultrasound reports and correlated them with the contemporaneous biochemical results. RESULTS: A total of 725 ultrasound examinations were performed over the review period. Sixty patients had at least one examination showing an abnormality of liver echo texture and in 39 patients this was a persisting finding. Seven patients (4.2%) developed frank cirrhotic change on ultrasound criteria, while 15 patients (8.9%) had evidence of persistent splenomegaly. Gall-bladder calculi were present in 4.8%. In 176 examinations (24%) there was disparity between the ultrasound findings and aspartate aminotransferase (AST) levels. In 3.0% of cases (five patients) there were persisting abnormalities of liver echo texture and persisting splenomegaly with a normal range AST value. CONCLUSION: No perfect method of assessing hepatobiliary involvement in CF is currently available. Ultrasonographic and biochemical assessment may reflect different aspects of disease progression. Routine use of ultrasound in annual assessment allows identification of a minority of patients with liver changes but with normal biochemistry.

Reversibility of the chronic effects of di(2-ethylhexyl)phthalate.

Fischer-344 rats treated with 12,500 ppm (728 and 879 mg/kg/d for male and females, respectively) and B6C3F1 mice treated with 6,000 ppm (1,227 and 1,408 mg/kg/d, respectively) di(2-ethylhexyl)phthalate (DEHP) in the diet for 78 weeks were allowed to recover for an additional 26 weeks on control diet. Blood was analyzed at weeks 78 and 104 from 10 animals per sex per group; animals were sacrificed at weeks 79 and 105 for histopathologic examination. The results are compared with data from animals continuously exposed to these dietary levels for 104 weeks (10, 11). Body weights and food consumption were measured monthly. BUN, albumin, and globulin that were significantly different for rats exposed to DEHP throughout 104 weeks, were comparable to controls for the recovery group. Reversibility of chronic effects on erythrocyte count, hemoglobin, and hematocrit values was apparent only for female rats. Chronic exposure demonstrated effects on liver, kidney, and testes weights. All organ weight effects except for testes for the Recovery group of rats, and all organ weight effects for mice, were reversible. Pigmentation of Kupffer cells and renal tubules present in chronically treated rats were not observed for the Recovery group. Lesions in the testes and pituitary gland were not reversible in rats. This may be a reflection of the senescence of the hypothalamic-gonad axis in rats. Cessation of exposure for mice resulted in amelioration of effects in the kidneys, liver, and testes. The extent of reversibility suggests that many chronic effects may be associated with a metabolic phenomenon such as peroxisome proliferation, which also reverted to control levels after 26 weeks of recovery.

Chronic toxicity of di(2-ethylhexyl)phthalate in mice.

B6C3F1 mice were treated with 0, 100, 500, 1500, or 6000 ppm di(2-ethylhexyl)phthalate (DEHP) in the diet for up to 104 weeks. Blood and urine were analyzed at Weeks 26, 52, 78, and 104 from 10 animals per sex per group. Body weights and food consumption were measured weekly for the first 16 weeks, then monthly thereafter. Survival was reduced for mice receiving 6000 ppm DEHP. Overall weight gains were significantly lower for the 6000-ppm male group, but there was no difference among female groups. Food consumption was not affected by exposure. No biologically significant changes in clinical chemistry, hematology, or urinalysis were observed. After 104 weeks of exposure, kidney weights for the 500- and 1500-ppm male, and 6000-ppm male/female groups were significantly lower than for the controls. Significantly higher liver weight was seen for the 500-, 1500-, and 6000-ppm male groups and the 6000-ppm female group of mice. Testis weights for the 500-, 1500-, and 6000-ppm males were significantly lower than for the controls. Uterine weights for the 6000-ppm group were significantly lower than for the controls. All organs were examined for histopathology. The incidence of hepatocellular lesions has been reported separately (R. M. David et al., 1999. Toxicol. Sci. 50, 195-205). Tumors were observed at > or = 500-ppm dosages, where peroxisome proliferation was significantly increased. A NOEL for both tumors and peroxisome proliferation was 100 ppm. In the study presented here, bilateral hypospermia in the testes of male mice, hepatocyte pigmentation and cytoplasmic eosinophilia in the liver, and chronic progressive nephropathy of male and female mice were observed at 6000 ppm. Hypospermia and chronic progressive nephropathy were also observed at 1500 ppm, where peroxisome proliferation was 2.7-6.8-fold higher than controls. Many lesions observed in rats were not seen in mice. A dose level of 500 ppm (98.5-116.8 mg/kg/day) was identified as a no-observed-adverse-effect level (NOAEL) for noncarcinogenic effects.

Chronic toxicity of di(2-ethylhexyl)phthalate in rats.

Fischer 344 rats were treated with 0, 100, 500, 2500, or 12,500 ppm di(2-ethylhexyl)phthalate (DEHP) in the diet for up to 104 weeks. Blood and urine were analyzed at weeks 26, 52, 78, and 104 from 10 animals per sex per group. Survival was slightly but not statistically reduced for rats receiving 12,500 ppm DEHP. Body weights and food consumption were significantly reduced for rats receiving the highest dose level of DEHP and occasionally for the male 2500-ppm group. BUN and albumin were significantly higher and globulin lower at nearly every sampling interval for the 12,500-ppm group compared with the controls. There was an increase in the mean activities of AST and ALT at 104 weeks, but no statistically significant differences were seen. Erythrocyte count, hemoglobin, and hematocrit values for the 12,500-ppm group were significantly lower than controls at nearly every sampling interval. No other differences in hematology were seen. No toxicologically significant changes were observed in urinalysis. At termination, relative lung weights for the 2500- and 12,500-ppm male groups of rats were significantly higher than for the controls. Absolute and relative liver and kidney weights for the 2500- and 12,500-ppm male rats, and liver weights for 12,500-ppm female rats were higher compared with the controls. Absolute and relative testes weights for the 12, 500-ppm male rats were lower compared with the controls. All organs were examined for histopathology. The incidence of hepatocellular lesions has been reported separately and correlated with the induction of peroxisomal enzyme activity (David et al., 1999). A dose level of 500 ppm was the NOEL for peroxisome proliferation. Bilateral aspermatogenesis in the testes, castration cells in the pituitary gland, spongiosis hepatis, and pancreatic acinar cell adenoma were observed for 12,500-ppm male rats. Aspermatogenesis and spongiosis hepatis were observed for 2500-ppm male rats, and aspermatogenesis was seen at 500 ppm. DEHP exposure exacerbated age-, species- or strain-related lesions such as mineralization of the renal papilla and chronic progressive nephropathy in male rats. Kupffer cell pigmentation and renal tubule pigmentation were seen in male and female 12,500-ppm rats. The increased incidence of spongiosis hepatis correlated with increased palmitoyl CoA oxidase activity, but the incidence of pancreatic acinar cell adenoma was increased only at the highest dose level of 12,500 ppm. These lesions, although typical of those seen with other peroxisome proliferators, may respond differently depending on the potency of the peroxisome proliferator. A dose level of 500 ppm (28.9-36.1 mg/kg/day) was considered to be the NOAEL.