Esophageal granular cell tumor and eosinophils: a multicenter experience

Background

Esophageal granular cell tumor (eGCT) is rare, and the recent literature suggests a link between eosinophilic esophagitis (EoE) and eGCT. The aim of our study was to determine if EoE or other disorders associated with eosinophilia are consistently associated with eGCT.

Methods

We retrospectively searched pathology databases of three academic institutions from 1999 to 2018 for eGCTs. The archived slides and medical records were reviewed.

Results

From 294,855 esophagogastroduodenoscopy procedures, 45 patients (17 males and 28 females) with eGCTs were identified. The patients (30–73 years in age, median 50) had eGCT 0.2–2.0 cm in size (average 0.71). Thirteen had a history of gastroesophageal reflux disease, 5 had Barrett esophagus/goblet cell metaplasia and 1 had EoE. Thirty-four eGCTs had intralesional eosinophils (14 with peak > 10 eosinophils/400x hpf); of these, 21 also had eosinophils in lamina propria (9 with peak > 10 eosinophils/hpf). eGCT with atypical features (including nuclear enlargement and prominent nucleoli) were more likely to have increased eosinophils in non-epithelial compartments than those without atypia. Pleomorphism and spindled cells were seen in 3 eGCT cases (mean peak intralesional eosinophils: 43 per hpf); 2 of these had goblet cell metaplasia. We found no association between EoE and eGCT, p = 0.5966, (95% C.I. 0.0276, 6.5389, Fisher’s exact test). Instead, most patients had gastroesophageal reflux disease or Barrett esophagus.

Conclusion

Eosinophilia, common in eGCT and adjacent stroma, likely drives atypical/reactive histologic features, but a pathogenic relationship between eosinophil rich inflammatory conditions and eGCT has not yet been established.

Clinical decision making in the provision of audiovisual care for upper limb trauma: a survey of UK experiences

Introduction

For many patients, audio-visual appointments have provided a timely and efficient way of seeking advice, assessment and treatment for their hand injuries during the NHS response to COVID-19. This study aimed to explore the experience of hand units across the UK in determining the safe and judicious use of audio-visual outpatient care for the management of acute upper limb trauma.

Methods

An online cross-sectional survey was sent to the therapy leads of hand units across the UK. Questions focused on the experience of using audio-visual technology in the management of upper limb trauma, and the relevant factors in determining its appropriate use. A deductive mixed methods analysis was used to identify both common themes and capture community experience and characteristics.

Results

A total of 51 out of 76 hand therapy units completed the survey; a response rate of 67%. Of these, 82% (42/51) reported using audio-visual technology to manage upper limb trauma during the UK COVID-19 lockdown. When determining patient suitability for audio-visual consultations, 73% (37/51) of respondents reported the use of COVID-19 guidelines, but only 35% (18/51) reported the use of a clinical decision-making tool. In agreement with our experience at Salisbury Hospital Foundation Trust, 92% (47/51) had concerns relating to the use of audio-visual care.

Conclusion

The choice of safely managed remote care or in-person consultation has, to date, largely relied on the discretion of the clinician. A carefully designed clinical decision-making tool for the management of upper limb trauma is needed for use both in clinical practice and in future service planning.

Abstract 981: Lymphocytic inflammation is a distinct feature of squamous metaplastic breast carcinomas and is associated with metastasis

Metaplastic breast carcinoma (MBC) is a rare subtype of triple negative breast carcinoma with frequent metastasis and poor response to chemotherapy. MBCs are defined by the presence of “metaplastic” components of spindle, squamous, or sarcomatoid histology (e.g. chondroid, osseous). To elucidate the molecular determinants of MBC, our lab analyzed the proteomics landscape of MBC which revealed that squamous MBC are significantly enriched for proteins that mediate inflammation and leukocyte activation, compared to spindle and sarcomatoid MBC. The presence and the significance of inflammation in MBC has not been investigated. To evaluate this, we retrieved 36 MBCs resected from 1988-2015 at our institution. Tumor sections were reviewed by three pathologists, and used to develop a tissue microarray (TMA) in duplicate. H&E whole sections were reviewed for MBC subtype and inflammation. The inflammatory infiltrate was assessed for type (lymphocytes, plasma cells, neutrophils, macrophages), localization (peripheral and/or intratumoral), and degree (0, 1, 2, 3). When the combined degree of inflammation at the periphery and intratumoral was ≥ 4, the degree was considered high. TMAs were immunostained for CD3/CD20 and CD4/CD8 double stains for further characterization. Of the 36 MBCs, 9 (25%) were chondroid, 7 (20%) were spindled, and 20 (55%) were squamous. When present, inflammation was predominantly lymphoid or lymphoplasmacytic (94%). Seventy-five % (15/20) of squamous MBC demonstrated significantly higher intratumoral inflammation (score ≥2) compared to 43% (3/7) and 11% (1/9) of spindle and chondroid, respectively (p=0.005). Squamous MBCs had a significantly higher degree (peripheral and intratumoral) of inflammation (15/20, 75%) compared to spindled (3/7, 43%) and chondroid (1/9, 11%) MBC's (p=0.004). The inflammatory infiltrate consisted of a mixture of B and T lymphocytes. Ninety-five % of cases with a T-cell infiltrate showed a predominance of CD4+ over CD8+ T-cells. Lymph node metastasis was seen in 11/30 MBC, and 9/11 (81%) demonstrated squamous morphology and a high degree of inflammation (p=0.017). Our results demonstrate that squamous MBC have a higher degree of inflammation within and at the periphery of the tumor compared to other MBC subtypes. A high degree of inflammation consisting of B and T lymphocytes in squamous MBC correlates with lymph node metastasis. The inflammatory infiltrate may contribute to the aggressive clinical behavior of squamous MBC, which warrants further investigation.

Citation Format: Emily McMullen, Stephanie L. Skala, Sabra Djomehri, May P. Chan, Celina G. Kleer. Lymphocytic inflammation is a distinct feature of squamous metaplastic breast carcinomas and is associated with metastasis [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 981.

Merkel cell carcinoma arising in association with cutaneous T-cell lymphoma: A potential diagnostic pitfall

Merkel cell carcinoma (MCC) is a rare, aggressive cutaneous neuroendocrine carcinoma with increased prevalence in patients with immunosuppression or B-cell neoplasms. To the best of our knowledge, an association with cutaneous T-cell lymphoma (CTCL) has not been previously described. In this report, we present two cases of MCC arising in the setting of CTCL. The first case was a female during her 70s with previously diagnosed stage IVA1 Sezary syndrome. Biopsy of a scaly patch showed two distinct abnormal cell populations. The first population consisted of hyperchromatic dermal and epidermotropic lymphocytes, expressing CD3 and CD4 with diminished CD7. The second population consisted of intraepidermal clusters of larger atypical cells that expressed synaptophysin, neurofilament, CK20, and Merkel cell polyomavirus transcript. The combination of findings was consistent with intraepidermal MCC in a background of CTCL. Excision showed residual intraepidermal MCC without dermal involvement. The second case was a male during his 50s with a longstanding history of mycosis fungoides, who presented with a new lesion on his right thigh. Biopsy and excision showed dermal MCC without secondary involvement by CTCL. Our cases show that MCC may rarely occur in the setting of T-cell lymphoma, and that intraepidermal MCC may mimic epidermotropic T-cells.

Thermosensitive Gel Containing Cellulose Acetate Phthalate-Efavirenz Combination Nanoparticles for Prevention of HIV-1 Infection

The objective of this investigation was to develop and evaluate a nano-microbicide containing a combination of cellulose acetate phthalate (HIV-1 entry inhibitor) and efavirenz (anti-HIV agent) for HIV prophylaxis. Cellulose acetate phthalate-efavirenz combination nanoparticles (CAP-EFV-NPs) were fabricated by the nanoprecipitation method and were characterized for particle size, zeta potential and encapsulation efficiency of efavirenz. CAP-EFV-NPs were incorporated into a thermosensitive gel (CAP-EFV-NP-Gel). CAP-EFV-NPs, CAP-EFV-NP-Gel and efavirenz solution were evaluated for cytotoxicity to HeLa cells and for in vitro short-term (1-day) and long-term (3-day) prophylaxis against HIV-1 infection in TZM-bl cells. CAP-EFV-NPs had size < 100 nm, negative surface charge and encapsulation efficiency of efavirenz was > 98%. CAP-EFV-NPs and CAP-EFV-NP-Gel were significantly less toxic (P < 0.01) to HeLa cells as compared to efavirenz solution. CAP-EFV-NPs showed significantly higher prophylactic activity (P < 0.01) against HIV-1 infection to TZM-bl cells as compared to efavirenz solution and blank CAP nanoparticles. CAP-EFV-NP-Gel can be a promising nano-microbicide for long-term HIV prophylaxis.

Polymeric nanoparticles containing combination antiretroviral drugs for HIV type 1 treatment

The use of combination antiretroviral nanoparticles (cART NPs) was investigated as a novel treatment approach for the inhibition of HIV-1 replication. We developed nanoparticles of biodegradable polymer, poly-(dl-lactide-co-glycolic acid; PLGA) containing efavirenz (EFV) and boosted lopinavir (lopinavir/ritonavir; LPV/r) by a high-pressure homogenization method. The method resulted in >79% drug entrapment efficiency for each of the three drugs. The average size of cART NPs was 138.3±55.4 nm as measured by dynamic light scanning, confirmed by scanning electron microscopy (SEM) with an average surface charge of -13.7±4.5. Lissamine-rhodamine-labeled fluorescent PLGA NPs exhibited efficient uptake in nonimmune (HeLa cells) and immune (H9 T cells) cells as measured by confocal microscopy. Cells treated with cART NPs resulted in minimal loss of cell viability over 28 days. Subcellular fractionation studies demonstrated that HIV-1-infected H9 monocytic cells treated with cART NPs contained significantly (p<0.05) higher nuclear, cytoskeleton, and membrane antiretroviral drug levels compared to cells treated with drug solutions alone. Finally, cART NPs efficiently inhibited HIV-1 infection and transduction. The IC50 for each of the three drugs in the cART NPs was <31 nM. These experiments demonstrate the efficacy of a novel PLGA NPs formulation for the delivery of cART to inhibit HIV-1 replication.

A survey of UK hand therapists' confidence in the interpretation of hand radiographs

Objective

To describe current practice among hand therapists in the UK when ordering and interpreting radiographs in clinical practice, in order to define confidence and establish national baselines. To highlight, promote discussion and propose the possible requirement for standardized education and a formal systematic assessment protocol for radiographic interpretation.

Methods

All British Association Hand Therapist (BAHT) registered centres in the UK were sent questionnaires and data collections sheets in order to ascertain current practice.

Results

The data suggest that of the 75 hand therapy centres in the UK who participated in this study 50.6% have therapists ordering radiographs. Of these 36% have formalized teaching and only 5.3% use a formal systematic assessment protocol for hand radiograph interpretation. The average confidence level on a visual analogue scale (VAS) was 5 (some confidence) with only four centres demonstrating above 6 (confident). Increased confidence levels were found to be associated with the availability of formal training and systematic assessment tools.

Conclusion

Centres using formalized training demonstrated a higher level of confidence than those without. The highest levels of confidence were in those centres whose therapists used a formal systematic assessment tool. The data collected suggests an education programme and standardized assessment protocol may assist the confidence of hand therapists in the radiographic assessment of hands.

Use of audiovisual equipment (SKYPE) for the treatment of hand injuries for remote consultations

Introduction

We present this case of a British patient living and working in Africa who used audiovisual (SKYPE) equipment as a treatment option for remote consultation. This was investigated in response to a request by the patient for further postoperative support at a distance after a complex hand surgery procedure.

Methods

Audiovisual (SKYPE) equipment was used by the team in combination with manual therapy as a means of seeking advice, progressing treatment and liaison with a specialist hand therapist and surgeon. The audiovisual equipment was used to complete follow-up of treatment episodes once the patient had returned to Africa.

Results

After five months of audiovisual consultations with the surgeon and clinical specialist hand therapist, the patient reported significant reductions in anxiety regarding the management of his extensive hand injury. The patient's active and passive range of movement and Disabilities of the Arm Shoulder and Hand scores had all improved. The wider multidisciplinary team in his local area was supported by a specialist service and evidence was gathered to support the organizational benefits of using audiovisual equipment.

Conclusion

This case report highlights the potential, clinical and cost benefits of utilizing audiovisual equipment in conjunction with other treatments in the management of remote hand injury patients.

Physical friction is under-recognized as an irritant that can cause or contribute to contact dermatitis

BACKGROUND

The role of physical friction as an irritant in the causation of contact dermatitis is under-recognized. Frictional dermatitis is defined as an eczematous process in which physical frictional trauma contributes to the induction of a dermatitis process.

OBJECTIVES

To examine the clinical background of patients in whom friction was contributing to dermatitis.

METHODS

Over a 30-month period during which 2700 new patients were seen, frictional irritancy was identified as playing a role in the dermatosis in 31 cases: in 27 of these, case notes were evaluated for a range of parameters.

RESULTS

Physical friction was identified as causing or contributing to the dermatitis in 18 men and nine women, mean age at onset 42 years. The hands, usually the fingers of the dominant hand, were affected in all but two cases. Occupational frictional activities were found in 25 cases: commonly handling small metal components, paper, cardboard or fabric, and driving. Potential frictional activities in hobbies were noted in 12 cases. Wet work irritancy contributed in four cases (15%). Patch testing showed relevant contact allergies as cofactors in seven of 25 subjects tested (26%). Psoriasis was a cofactor in four (15%), and atopic dermatitis in 11. The study was selective, being based in a teaching hospital clinic with a special interest in contact dermatitis. Frictional irritancy is often one of several factors contributing to dermatitis.

CONCLUSIONS

The contribution of friction to contact dermatitis is under-recognized probably because dermatologists do not think about the potential for physical forces to induce eczematous changes in the skin.

Environmental tobacco smoke exposure patterns: a subanalysis of the Canadian Human Time-Activity Pattern Survey

This subanalysis of the Canadian Human Activity Pattern Survey examines environmental tobacco smoke (ETS) exposure in non-smoking respondents relative to age, sex, socioeconomic status and prevalence of asthma. 2,381 respondents (response rate 64.5%) from Toronto, Vancouver, Edmonton and Saint John completed a 24-hour recall time-activity diary. For each activity and location, respondents were asked, "was there any smoking during the activity?" Among non-smoking adults, youth, children and asthmatics, the rates of ETS exposure were 32%, 34%, 30% and 42% respectively. Regarding the location of exposure, adults reported ETS exposure in various locations (work, bars and restaurants), including home. Children experienced the most exposure at home, primarily between 4 p.m. and midnight. Adults reported ETS mainly in the living room (16%) and vehicles (13%); for children, the living room (22%) and the bedroom (13%) were the most common locations. Determining characteristic time and location patterns for ETS exposure underpins educational strategies to help non-smokers avoid ETS exposure.

Dental amalgam and multiple sclerosis: a case-control study in Montreal, Canada

BACKGROUND

The aetiology of multiple sclerosis (MS) remains poorly understood. Dental amalgams containing mercury have recently been suggested as a possible risk factor for MS.

METHODS

In a case-control study conducted between 1991 and 1994, we interviewed a total of 143 MS patients and 128 controls, to obtain information on socio-demographic characteristics and the number of dental amalgams and the time since installation based on dentists' records.

RESULTS

Neither the number nor the duration of exposure to amalgams supported an increased risk of MS. After adjustment for age, sex, smoking, and education those who had more than 15 fillings had an odds ratio (OR) of 2.57 (95% CI: 0.78-8.54) compared to those who had none; for individuals whose first amalgam was inserted more than 15 years prior to the study, we found an OR of 1.34 (95% CI: 0.38-4.72).

CONCLUSIONS

Although a suggestive elevated risk was found for those individuals with a large number of dental amalgams, and for a long period of time, the difference between cases and controls was not statistically significant.

Pharmacokinetics of benzo[a]pyrene in the rat

Groups of 4 male Wistar rats were dosed intravenously with 14C-labeled benzo[a]pyrene dissolved in an Emulphor/water vehicle at 3 different dose levels and killed at 1 of 15 specific time intervals from 5 min to 32 h after dosing. 14C-Radiolabel concentration-time data were obtained for blood, brain, adipose, heart, kidney, liver, lung, spleen, and testes. Benzo[a]pyrene concentration-time data were obtained for blood, adipose, kidney, liver, and lung. Appropriate mathematical models were fitted to these data and to the data for metabolites derived as the residuals from 14C-radiolabel minus benzo[a]pyrene difference, where applicable. Nonlinear kinetics were found for 14C-radiolabel in liver, while the data from lung for both 14C-radiolabel and for benzo[a]pyrene per se supported the binding of benzo[a]pyrene in that tissue.

Parental reporting of childrens' coughing is biased

Assessment of cough in the clinical setting as well as in community-based studies of respiratory epidemiology has relied on self-reports. To examine the accuracy and potential for systematic bias in reported cough during a field study, questionnaires administered to parents about their childrens' coughing were compared to overnight cough recordings performed in 145 homes in the community of Wallaceburg, Canada. Percentage agreement between reported and recorded coughing was low, with kappa statistics ranging from 0.02-0.10. Compared to non-smoking parents, smokers under-reported their childrens' coughing (p = 0.01). The association found between parental smoking and recorded coughing was biased towards the null when reported coughing was substituted for recorded coughing: the odds ratio between parental smoking and recorded coughing was 3.1 (95% CI: 1.1-8.8) whereas for reported coughing it was 0.6 (95% CI: 0.2-1.7), the difference in the odds ratios being significant at p = 0.03. When carrying out field surveys, consideration should be given to measuring cough in a subsample of the population in order to estimate the degree of bias inherent in the questionnaire-based results.

Indoor air quality and health: validity and determinants of reported home dampness and moulds

BACKGROUND

Questionnaire-based surveys from several countries have consistently detected adverse health associated with home dampness and mould growth.

METHODS

To test the validity of questions commonly used to indicate the presence of indoor mould, questionnaires were administered in 403 homes where dust samples were taken for viable fungi and air samples for ergosterol.

RESULTS

Geometric mean concentrations of the total viable fungi were 255 (SE 116) x 10(3) CFU/g when mouldy odours were reported and 155 (SE 55) when odours were not reported (P = 0.01). Similarly, reported water damage was associated with a 50% increase (P = 0.06). Geometric mean concentrations of the predominantly indoor-source fungi, Aspergillus plus Penicillium, were twice as high when mould or mildew was reported than when not mentioned (P = 0.01). The presence of reported mould or water damage was unrelated to the presence of detectable levels of ergosterol. There was evidence for reporting bias: in the presence of low concentrations of viable fungi in dust, respondents reporting allergies were more likely to report visible mould growth (odds ratio [OR] = 1.8, 95% confidence interval [CI]: 0.9-3.5, P = 0.10. In the presence of elevated concentrations of dust fungi, respondents who smoked were less likely to report visible mould growth, (OR = 0.4, 95% CI: 0.2-0.7, P = 0.005).

CONCLUSIONS

Reported mould, water damage, and mouldy odours were associated with elevated levels of indoor fungi. However, inaccuracy was high and there was evidence of a systematic reporting bias. Future research should concentrate on developing accurate objective measures of exposure to fungi, and then use this information to develop valid questionnaires. Currently, objective measures not questionnaires, are recommended to clarify the health effects of indoor fungi.

Sensitivity of lungs of aging Fischer 344 rats to ozone: assessment by bronchoalveolar lavage

Biological effects indicators in bronchoalveolar lavage fluid were studied in Fischer 344 rats of different ages after exposure to 0.4-0.8 ppm ozone for periods of 2-6 h on a single day or on 4 consecutive days. The magnitude of alveolar protein transudation induced by ozone was not different between age groups, but the interindividual variability of protein changes was higher in senescent (24-mo-old) rats. By comparison to juvenile (2-mo-old) and adult (9-mo-old) rats, senescent animals had higher increases of interleukin-6 (up to 10-fold higher) and N-acetyl-beta-D-glucosaminidase (NAGA; 2-fold higher) in lung lavage after ozone. Ascorbic acid was lower in lungs of senescent rats (one-half of juvenile values), and acute ozone exposure brought a further decrease in lung ascorbate. Whereas alveolar protein transudation was attenuated after ozone exposure on 4 days, persistent elevation of NAGA in senescent rats suggested only partial adaptation. Injection of endotoxin did not modify the patterns of effects. Incorporation of 18O-ozone into macrophages and surfactant was not different between age groups, indicating that the magnified biological responses in senescent rats were not dominated by differences in internal dose of ozone. The results indicate that senescent rats respond differently than juvenile and adult rats to lung injury.

The Canadian Human Activity Pattern Survey: report of methods and population surveyed

The assessment of health risk due to environmental contaminants depends upon accurate estimates of the distribution of population exposures. Exposure assessment, in turn, requires information on the time people spend in micro-environments and their activities during periods of exposure. This paper describes preliminary results including study methodology and population sampled in a large Canadian survey of time-activity patterns. A 24-hour diary recall survey was performed in 2381 households (representing a 65% response rate) to describe in detail the timing, location and activity pattern of one household member (the adult or child with the next birthday). Four cities (Toronto, Vancouver, Edmonton and Saint John, NB) and their suburbs were sampled by random-digit dialling over a nine-month period in 1994/1995. Supplemental questionnaires inquiring about sociodemographic information, house and household characteristics and potential exposure to toxins in the air and water were also administered. In general, the results show that respondents spend the majority of their time indoors (88.6%) with smaller proportions of time outdoors (6.1%) and in vehicles (5.3%). Children under the age of 12 spend more time both indoors and outdoors and less time in transit than do adults. The data from this study will be used to define more accurately the exposure of Canadians to a variety of toxins in exposure assessment models and to improve upon the accuracy of risk assessment for a variety of acute and chronic health effects known or suspected to be related to environmental exposures.

The effect of different levels of dietary alpha-linolenic and other fatty acids on mammary gland ductular cell proliferation in female Swiss Webster mice

In previous work we have shown that changing the fatty acid composition of a constant amount of fat in a modified AIN-76A diet affected the level of ductular cell proliferation in the mammary glands of young virgin female Swiss Webster mice. In particular, linoleic acid concentrations of 5-10% of the total fat in the diet led to variable but appreciably higher levels of proliferation than did higher levels of linoleic acid. In this report it is shown that feeding low levels of the total fat as alpha-linolenic acid (0-5%) resulted in a similar effect. In addition the effects of other fats including menhaden oil, were further investigated.

The effect of butylated hydroxytoluene on the growth of enzyme-altered foci in male Fischer 344 rat liver tissue

Butylated hydroxytoluene (BHT) is a synthetic, food-use, phenolic antioxidant. It has previously been demonstrated to be operationally non-genotoxic and, in addition, failed to induce biologically significant increases in cellular proliferation in the liver, urinary bladder and thyroid gland on feeding to young adult Wistar rats. Nevertheless, it has been reported to enhance the yield of liver tumors when fed to rats or mice that developed an appreciable background incidence of these tumors without treatment. In order to resolve this situation, cell proliferation in response to BHT treatment was studied in enzyme-altered foci (EAF) induced in male Fischer 344 rats using the Solt-Farber procedure. It was demonstrated that feeding 0.5% dietary BHT for 30 days after the induction of EAF led to a 20- to 30-fold increase in the gamma-glutamyltranspeptidase-positive areas in both DEN- and saline-initiated rat livers, but to no major effects in glutathione S-transferase placental form (GSTP)-positive foci. Cell proliferation rates within EAF and surrounding normal liver were measured using different histological techniques. Nuclear labeling with [3H]thymidine and proliferating cell nuclear antigen (PCNA) over the total hepatocyte population indicated that BHT approximately doubled nuclear labeling in rats initiated with DEN. PCNA labeling in GSTP-positive foci was not affected by BHT. In GSTP-positive foci, evaluation of nucleolar organizer regions (AgNOR), which reflect cell proliferative in addition to transcriptional activity of ribosomal RNA, was achieved using a novel double staining technique. BHT diet did not affect the number of AgNOR per nucleus or the percentage AgNOR area/nucleus. Nevertheless, both PCNA labeling and the AgNOR area per nucleus were significantly greater in GSTP-positive foci compared with non-focal regions in rats fed either BHT or control diets. These results are discussed in the light of further experimental work required to determine the relevance of these data to possible human risk assessment for BHT.

Effect of addition of dried healthy or diseased parsnip root tissue to a modified AIN-76A diet on cell proliferation and histopathology in the liver, oesophagus and forestomach of male Swiss Webster mice

Umbelliferous crop plants, including the parsnip (Pastinaca sativa L.), elaborate enhanced levels of furocoumarins, including psoralens, when subjected to biotic or abiotic stress. These furocoumarins are recognized to lead to phototoxicity. In this study, the effect of these agents, which are present in diseased parsnip root tissue, on the liver and two tissues on the route of entry to the body (the oesophagus and forestomach) were investigated. Young male Swiss Webster mice were fed for approximately 30 days with modified AIN-76A diets containing 32.5% dried healthy, 32.5% apparently healthy or 32.5% fungicide-treated parsnip root tissue, and 8, 16 or 32.5% dried diseased (Phoma complanata-infected) parsnip root tissue. As controls, three modified AIN-76A diets differing in their edible starch-to-sucrose ratios (C1-C3) were administered for an equal time. Dried healthy parsnip root tissue, compared with controls, did not significantly affect any of the indices of cellular proliferation or histopathological parameters that were assessed. Histopathological examination of the oesophagus and forestomach demonstrated no significant changes as a result of feeding any of the diets containing parsnip tissue. In the liver, the highest level (but neither of the two lower levels) of dried diseased parsnip root tissue led to swelling of the cytoplasm in cells surrounding the central vein of hepatic lobules, with consequent compression of the peripheral cells. Using [3H]thymidine radioautography, a dose-related increase in cell labelling with the level of diseased parsnip root tissue was demonstrated in the liver. Compared with control diet C2 only, the extent of [3H]thymidine labelling in the liver was increased in mice receiving apparently healthy parsnip tissue; a slight, not statistically significant, increase was also noted with fungicide-treated parsnip tissue. Increased [3H]thymidine labelling with the feeding of diseased parsnip tissue was also found in the greater curvature of the forestomach and the region of the oesophageal-forestomach junction, but not at the glandular junction of the forestomach nor in the mid-oesophagus.

Levels of chlorinated hydrocarbon residues in Canadian human breast milk and their relationship to some characteristics of the donors

A total of 412 breast milk samples from women in all provinces of Canada were analysed for polychlorinated biphenyls, eight chlorinated benzenes, 2,3-dichloronaphthalene, Mirex, alpha, beta, gamma and delta hexachlorocyclohexane, alpha and gamma chlordane, oxychlordane, transnonachlor, p,p'-DDT and some analogues, heptachlor epoxide, dieldrin and octachlorostyrene. No delta-hexachlorocyclohexane, heptachlor or aldrin were found in any of the samples, while median levels of the 1,2,4- and 1,3,5-trichlorobenzene, 1,2,3,4- and 1,2,3,5-tetrachlorobenzenes, gamma chlordane, o,p'-DDT and octachlorostyrene were all less than the minimum detectable level (MDL). All other compounds were present at median levels ranging from < 0.1 to 7.2 ng/g whole milk, but did not occur in all samples. Di to tetrachlorobenzenes, except 1,2,4-trichlorobenzene, 2,3-dichloronaphthalene and alpha-chlordane were observed in < 50% of the samples. From 1967 to 1986 a steady decline of hexachlorobenzene, gamma-hexachlorocyclohexane, DDTs, heptachlor epoxide and dieldrin was observed in Canadian breast milk. In addition, a decrease in some chlorinated benzenes, gamma-hexachlorocyclohexane and PCBs was also observed between 1982 and 1986. Levels of oxychlordane and trans-nonachlor remained constant. Canadian breast milk contamination appears to be one of the lowest among the industrialized nations. Regional and provincial differences in residue levels appeared minimal, although more often samples from Quebec and British Columbia had higher levels of some contaminants, such as oxychlordane, than samples from other provinces. No relationship was found between maternal age and residue levels, but some contaminants, such as PCBs, were significantly higher in the milk of mothers who breastfed their first child as compared to multiparous mothers. Breast milk residue levels were not related to fish consumption.

Effect of varying the type of fat in a semi-purified AIN-76A diet on cellular proliferation in the mammary gland and intestinal crypts in female Swiss Webster mice

Young virgin female Swiss Webster mice were fed AIN-76A semi-purified diets containing equal weights of different fats for approximately 30 days. Using [3H]thymidine radioautography, it was established that mice fed 100% lard or high levels of fish oils (menhaden oil or cod liver oil) developed elevated cellular proliferation in the duct cells of the mammary gland and an increased number of labeled cells/crypt in the crypts of the colo-rectum accompanied by an increase in the size of the proliferative compartment. A possible inverse correlation between the level of [3H]thymidine labeling in the mammary gland, but not in the colo-rectum, and the linoleic acid content of individual diets may help to explain the significance of these observations. The effect of adding an antioxidant mixture to these diets was to reduce the excess proliferation induced in the intestinal crypts by lard or fish oil to the level induced by soybean oil, but only partially so in the duct cells of the mammary gland.

Liver DNA adducts in methyl-deficient rats administered a single dose of aflatoxin B1

Using an 8 week Solt-Farber protocol with selection pressure (2-acetylaminofluorene/partial hepatectomy) applied during weeks 6 and 7, we have observed that a single oral administration of aflatoxin B1 (AFB1) to Fischer 344 rats on day 1 of the study, followed by a 3 week feeding regimen of either a methyl-deficient (CMD) or a basal (CMS) diet, results in a relative increase in hepatic preneoplastic lesions in CMD diet fed rats. It has previously been shown that a multiple dosing regimen with AFB1, started after 3 weeks of CMD diet, enhances tumor incidence. In the present study, the role of metabolic activation in the induction of preneoplastic lesions, and liver DNA adduct levels after the first dose of AFB1 in the tumorigenesis model have been investigated. AFB1-DNA adducts were determined at 2-168 h following a single non-necrogenic (100 micrograms/kg body wt) or necrogenic (600 micrograms/kg body wt) dose of AFB1 on day 1 or day 21 of a 3 week treatment with a complete basal or CMD diet. In all rats irrespective of dose, dietary treatment or time of AFB1 dosing, the patterns of adduct formation and repair did not change. In rats receiving AFB1 on day 1, total DNA adduct levels between the diet or dose groups were not significantly different, and quantitatively did not correlate with the observed increase in preneoplastic lesions, suggesting a contribution by additional factors in the initiation of these lesions. Administration of AFB1 on day 21, however, resulted in significantly reduced levels of total adducts at both dose levels in CMD diet fed rats compared to controls. Serum biochemistry data suggest that a prolonged exposure to CMD diet may cause pathological and/or biochemical alterations in hepatocytes with a resultant decrease in metabolic activation of AFB1, thus making it difficult to evaluate whether DNA damage is directly related to tumorigenesis.