Retrospective assessment of tolerability and efficacy of zoledronate in the palliative treatment of cancer-bearing dogs

Zoledronate is a bisphosphonate frequently used for the treatment of hypercalcaemia of malignancy and tumour-associated bone pain in dogs, however, there is a paucity of information regarding its use in veterinary medicine. The aim of this retrospective study was to report the tolerability of zoledronate in the palliative treatment of cancer-bearing dogs and secondarily to to assess the efficacy of zoledronate for the treatment of hypercalcaemia of malignancy. Thirty-seven dogs (22 with tumour-associated bone pain and 15 with hypercalcaemia of malignancy) that received 114 zoledronate infusions were included. Tolerability was assessed by the absence of post-zoledronate hypocalcaemia or other adverse events as defined by Veterinary Cooperative Oncology Group-Common Terminology Criteria for Adverse Events criteria. Efficacy was assessed by comparison of available ionized calcium levels before and after zoledronate administration in hypercalcaemic dogs. In 79% of zoledronate infusions, no adverse events were reported. The majority of adverse events which occurred in the other 21% of infusions could be attributed to concurrent chemotherapy or the underlying neoplastic disease. There was a small but significant increase in creatinine following treatment with zoledronate, however, none of the dogs developed clinically significant renal disease. In eight hypercalcaemic dogs with available ionized calcium following zoledronate administration, ionized calcium decreased rapidly within 7 days following treatment with zoledronate. Zoledronate is well-tolerated with few recorded adverse events, however, monitoring of serum creatinine is advised. Zoledronate seems to be effective in the treatment of hypercalcaemia of malignancy.

The prevalence and characterisation of TRAF3 and POT1 mutations in canine B-cell lymphoma

The genetic and mutational basis of canine lymphoma remains poorly understood. Several genes, including TRAF3 and POT1, are mutated in canine B-cell lymphoma (cBCL), and are likely involved in the pathogenesis of this disease. The purpose of this study was to assess the prevalence of TRAF3 and POT1 mutations in a cohort of dogs with cBCL, compared to dogs with non-cBCL diseases (including four dogs with T-cell lymphoma [cTCL]). Forty-nine dogs were included (n = 24 cBCL; n = 25 non-cBCL). Eleven dogs had matched non-tumour DNA assessed to determine if mutations were germline or somatic. All dogs had TRAF3 and POT1 assessed by Sanger sequencing. The prevalence of deleterious TRAF3 and POT1 mutations in cBCL was 36% and 17%, respectively. A deleterious TRAF3 mutation was suspected to be germline in 1/5 cases with matched non-tumour DNA available for comparison. Deleterious mutations were not found in specimens from the non-cBCL group. Several synonymous variants were identified in both genes in cBCL and non-cBCL samples, which likely represent polymorphisms. These results indicate TRAF3 and POT1 mutations are common in cBCL. Deleterious TRAF3 and POT1 mutations were only identified in dogs with cBCL, and not in dogs with non-cBCL diseases, suggesting they are important in the pathogenesis of cBCL. Future studies to investigate the prognostic and therapeutic implications of these mutations are required.

Spinal Opioid Tolerance Depends upon Platelet-Derived Growth Factor Receptor-β Signaling, Not μ-Opioid Receptor Internalization

Opioids are some of the most potent analgesics available. However, their effectiveness is limited by the development of analgesic tolerance. Traditionally, tolerance was thought to occur by termination of μ-opioid receptor (MOR) signaling via desensitization and internalization. Contradictory findings led to a more recent proposal that sustained MOR signaling caused analgesic tolerance. However, this view has also been called into question. We recently discovered that the platelet-derived growth factor receptor(PDGFR)-β signaling system is both necessary and sufficient to cause opioid tolerance. We therefore propose a completely new hypothesis: that opioid tolerance is mediated by selective cellular signals and is independent of MOR internalization. To test this hypothesis, we developed an automated software-based method to perform unbiased analyses of opioid-induced MOR internalization in the rat substantia gelatinosa. We induced tolerance with either morphine, which did not cause MOR internalization, or fentanyl, which did. We also blocked tolerance by administering morphine or fentanyl with the PDGFR-β inhibitor imatinib. We found that imatinib blocked tolerance without altering receptor internalization induced by either morphine or fentanyl. We also showed that imatinib blocked tolerance to other clinically used opioids. Our findings indicate that opioid tolerance is not dependent upon MOR internalization and support the novel hypothesis that opioid tolerance is mediated by intracellular signaling that can be selectively targeted. This suggests the exciting possibility that undesirable opioid side effects can be selectively eliminated, dramatically improving the safety and efficacy of opioids. SIGNIFICANCE STATEMENT: Classically, it was thought that analgesic tolerance to opioids was caused by desensitization and internalization of μ-opioid receptors (MORs). More recently, it was proposed that sustained, rather than reduced, MOR signaling caused tolerance. Here, we present conclusive evidence that opioid tolerance occurs independently of MOR internalization and that it is selectively mediated by platelet-derived growth factor receptor signaling. This novel hypothesis suggests that dangerous opioid side effects can be selectively targeted and blocked, improving the safety and efficacy of opioids.

Community health perceptions and human environmental exposure to chromium contamination in a small New Jersey City

Following a 1983 chromic acid (hexavalent chromium [CrVI]) spill from a Garfield, NJ electroplating plant, CrVI-contaminated water was found in a local firehouse basement in 1993. An ATSDR public health advisory was issued for the plant site in 2010, and from 2008-2015, fourteen residential properties have required remediation to address CrVI-contaminated dust in the basements. As part of the Community Outreach and Engagement Core of the NYU NIEHS Center, seventytwo Garfield residents aged 18-65 years, participated in a community survey with the goal of identifying concerns related to environmental and community health. Thirty-two percent responded that they 'didn't know' if they were exposed to chemicals or pollutants where they live. This finding suggests a limited awareness of environmental chemical exposures, chromium contamination and/or potential exposure to CrVI. Furthermore, toenail clippings were collected from forty-seven Garfield residents and analyzed for total chromium levels to assess potential long-term exposure. On average, residents living on/inside the contaminated plume area had higher total chromium levels in their toenail clippings than residents living outside the plume area. However, chromium levels for all participants were within the range of historical normal. This study highlights the value of partnerships between environmentally-impacted community's and academic scientists working together to identify potential contaminant exposures and address public health concerns through research and environmental health education.

Correlates of toenail selenium and its cross-sectional association with metabolic syndrome

BACKGROUND

The present study aimed to identify independent correlates of toenail selenium levels and to examine the association between toenail selenium levels and metabolic syndrome in Korean adults.

METHODS

Cross-sectional analysis was conducted using baseline data from the Trace Element Study of Korean Adults in the Yeungnam area, an ongoing cohort study of Korean adults over the age of 35 years. The baseline survey consisted of questionnaires on demographics, lifestyle characteristics and medical information. Dietary information was obtained through a validated semi-quantitative food frequency questionnaire. Toenail selenium levels were quantified using neutron activation analysis. Biomarkers associated with metabolic syndrome were obtained from biennial medical check-ups.

RESULTS

In the multivariable-adjusted analyses, independent lifestyle and dietary correlates of higher selenium levels were alcohol drinking (4.62% higher than nondrinking) and egg intake (0.43% higher per weekly serving), whereas current smoking (5.42% lower than nonsmoking) and vegetable consumption (0.05% lower per weekly serving) were associated with lower toenail selenium levels. In the multivariable adjusted logistic regression, no significant association was observed between toenail selenium levels and metabolic syndrome (odds ratio = 1.33, 95% confidence interval = 0.58-3.05).

CONCLUSIONS

Multiple lifestyle and dietary factors influenced toenail selenium levels, although no meaningful association was observed between toenail selenium levels and metabolic syndrome in Korean adults. Future prospective large-scale cohort studies are required to determine whether there is a causal relationship between selenium levels and metabolic syndrome in Korean adults.

Evaluation of the modified Glasgow Prognostic Score to predict outcome in dogs with newly diagnosed lymphoma

The modified Glasgow Prognostic Score (mGPS) assigns a numerical value (0-2) from pre-treatment serum concentrations of C-reactive protein (CRP) and albumin to predict patient outcome. CRP and albumin were evaluated in 77 untreated dogs with lymphoma to determine the relationship of mGPS to clinicopathological parameters and whether it could predict progression-free (PFS) and overall survival (OS) in treated dogs. mGPS distribution was significantly associated with clinical stage, substage b, weight loss, gastrointestinal disturbances and lethargy at presentation. On univariate analysis, mGPS was significantly associated with OS and PFS, with shorter median survival times for mGPS 2 compared to mGPS 0 and 1 combined. Hypoalbuminaemia significantly reduced OS and PFS, however increased CRP had no effect. Only clinical stage was significantly associated with OS and PFS on both univariate and multivariate analysis. mGPS has potential prognostic value for canine lymphoma , but further studies are needed.

Use of neutrophil to lymphocyte ratio for predicting histopathological grade of canine mast cell tumours

Canine mast cell tumours (MCTs) are variable in their biological behaviour and treatment decisions depend heavily on the histopathological grade. Biomarkers such as neutrophil to lymphocyte ratio (NLR) and albumin to globulin ratio are used to predict the biological behaviour of human neoplasms, but have not been widely studied in dogs. A retrospective analysis identified 62 cases of gross MCT (14 high-grade, 48 low-grade tumours). Median NLR was significantly different between high- and low-grade MCT and tumours at different locations. A multivariable model identified increasing NLR (OR 2.0) and age (OR 1.7) to be associated with an increased risk of high-grade MCT. Receiver operating characteristic curve analysis identified an NLR threshold value of 5.67 (sensitivity 85.7 per cent; specificity 54.2 per cent) for predicting a high-grade MCT. An NLR threshold of 5.67 could be useful alongside existing tools (appearance, location, etc.) to help to predict the grade of MCT. With further validation, this biomarker could be used to guide clinical decisions before obtaining a histopathological diagnosis.

Fibulin-2 is involved in early extracellular matrix development of the outgrowing mouse mammary epithelium

Cell-matrix interactions control outgrowth of mammary epithelium during puberty and pregnancy. We demonstrate here that the glycoprotein fibulin-2 (FBLN2) is strongly associated with pubertal and early pregnant mouse mammary epithelial outgrowth. FBLN2 was specifically localized to the cap cells of the terminal end buds during puberty and to myoepithelial cells during very early pregnancy (days 2-3) even before morphological changes to the epithelium become microscopically visible, but was down-regulated thereafter. Exposure to exogenous oestrogen (E2) or E2 plus progesterone (P) increased Fbln2 mRNA expression in the pubertal gland, indicating hormonal control. FBLN2 was co-expressed and co-localised with the proteoglycan versican (VCAN) and co-localised with laminin (LN), while over-expression of FBLN2 in HC-11 cells increased cell adhesion to several extracellular matrix proteins including LN and fibronectin, but not collagens. Mammary glands from Fbln2 knockout mice showed no obvious phenotype but increased fibulin-1 (FBLN1) staining was detected, suggesting a compensatory mechanism by other fibulin family members. We hypothesise that similar to embryonic aortic smooth muscle development, FBLN2 and VCAN expression alters the cell-matrix interaction to allow mammary ductal outgrowth and development during puberty and to enable epithelial budding during pregnancy.

A randomized trial investigating the efficacy and safety of water soluble micellar paclitaxel (Paccal Vet) for treatment of nonresectable grade 2 or 3 mast cell tumors in dogs

BACKGROUND

Effective treatments for dogs with advanced stage mast cell tumors (MCT) remain a pressing need. A micellar formulation of paclitaxel (paclitaxel [micellar]) has shown promise in early-phase studies.

HYPOTHESIS/OBJECTIVES

The objective was to demonstrate greater activity for paclitaxel (micellar) compared with lomustine. The null hypothesis was μ(p) = μ(L) (ie, proportion of responders for the paclitaxel [micellar] and lomustine groups, respectively).

ANIMALS

Two hundred and fifty-two dogs with advanced stage nonresectable grade 2 or 3 MCT.

METHODS

Prospective multicenter randomized double-blind positive-controlled clinical trial. The primary endpoint was confirmed overall response rate (CORR) at 14 weeks. A secondary endpoint, biologic observed response rate (BORR), also was calculated. Safety was assessed by the characterization and grading of adverse events (AE).

RESULTS

Overall CORR (7% versus 1%; P = .048) and BORR (23% versus 10%; P = .012) were greater for paclitaxel (micellar) compared with lomustine. Paclitaxel (micellar)-treated dogs were 6.5 times more likely to have a confirmed response and 3.1 times more likely to experience a biologic observed response. The majority of AE with paclitaxel (micellar) were transient and clinically manageable. Twenty-seven dogs (33%) receiving lomustine were discontinued because of hepatopathy compared with 3 dogs (2%) receiving paclitaxel (micellar) (P < .0001; odds ratio 26.7).

CONCLUSIONS AND CLINICAL IMPORTANCE

Paclitaxel (micellar)'s activity and safety profile are superior to lomustine. The addition of an active and novel taxane to the veterinary armamentarium could fill a substantial need and, as its mechanism of action and AE profile do not overlap with currently available TKI, its availability could lead to effective combination protocols.

Efficacy of bevacizumab plus erlotinib for advanced hepatocellular carcinoma and predictors of outcome: final results of a phase II trial

OBJECTIVE

A phase II study was performed to evaluate the efficacy and tolerability of bevacizumab and erlotinib in advanced hepatocellular carcinoma (HCC) patients, and to investigate clinical and molecular predictors of outcome.

METHODS

59 patients with advanced HCC received 10 mg/kg i.v. of bevacizumab every 14 days and 150 mg p.o. of erlotinib daily. The primary endpoint was progression-free survival (PFS) at 16 weeks. Clinical characteristics and plasma biomarkers expression levels were analyzed.

RESULTS

PFS at 16 weeks was 64% (95% CI 51-76): 14 patients achieved partial response (24%), 33 had stable disease (56%), 6 progressed (10%), and 6 were not evaluable (10%). Median overall survival was 13.7 months (95% CI 9.6-19.7), and median PFS was 7.2 months (95% CI 5.6-8.3). Grade 3-4 adverse events included fatigue (30%), diarrhea (17%), hypertension (14%), elevated transaminases (12%), and gastrointestinal hemorrhage (10%). High plasma angiopoietin-2, epidermal growth factor receptor, and endothelin-1, and lack of acneiform rash were associated with poor outcome.

CONCLUSIONS

The combination of bevacizumab with erlotinib achieved encouraging results in patients with advanced HCC. Current correlatives may help to guide future HCC studies.

Fish oil, selenium and mercury in relation to incidence of hypertension: a 20-year follow-up study

OBJECTIVES

Long-chain omega-3 polyunsaturated fatty acids (LCω3PUFAs), selenium (Se) and mercury (Hg) are three important components in fish. The cardioprotective effect of LCω3PUFA intake has been recognized; however, the hypothesis that this benefit may be greatest with high Se and low Hg levels has not been investigated.

DESIGN

A cohort of 4508 American adults aged 18-30, without hypertension at baseline in 1985, were enrolled. Six follow-ups were conducted at examinations in 1987, 1990, 1992, 1995, 2000 and 2005. Diet was assessed by a validated interviewer-administered quantitative food frequency questionnaire at exams in 1985, 1992 and 2005. Incident hypertension was defined as first occurrence at any follow-up examination of systolic blood pressure (BP) ≥ 140 mmHg, diastolic BP ≥ 90 mmHg or taking antihypertensive medication. Toenail clippings were collected in 1987, and Se and Hg levels were quantified by instrumental neutron-activation analysis.

RESULT

Participants in the highest LCω3PUFA intake quartile had a significantly lower incidence of hypertension (hazard ratio: 0.65; 95% CI: 0.53-0.79; P(trend) < 0.01) compared to those in the lowest quartile after adjustment for potential confounders. Docosahexaenoic acid showed a greater inverse association than eicosapentaenoic acid. The inverse association of LCω3PUFA intake with hypertension appeared more pronounced at higher Se and lower Hg levels, although interaction tests were statistically nonsignificant.

CONCLUSIONS

Our findings indicated that LCω3PUFA intake was inversely associated with incidence of hypertension. The prior hypothesis that the potential antihypertensive effect of LCω3PUFA intake varies depending on joint levels of Se and Hg received modest support and cannot be ruled out.

15-LOX-1 transcription suppression through the NuRD complex in colon cancer cells

15-Lipoxygenase-1 (15-LOX-1) is transcriptionally silenced in cancer cells, and its transcription reactivation (for example, through histone deacetylase inhibitors (HDACIs)) restores apoptosis to cancer cells. However, the exact mechanism underlying 15-LOX-1 transcription reactivation in cancer cells is still undefined. Therefore, we evaluated the critical mechanisms required for 15-LOX-1 transcription reactivation in colon cancer cells. Specific HDAC1 and HDAC2 inhibition activated 15-LOX-1 transcription. 15-LOX-1 transcription was repressed through transcription repressor complex recruitment in the region of -120 to -391 of the 15-LOX-1 promoter. The nucleosome remodeling and histone deacetylase (NuRD) repression complex was recruited to this region. Depsipeptide significantly reduced the recruitment of NuRD key components (for example, metastasis-associated protein 1 (MTA1) and HDAC1) to the 15-LOX-1 promoter before 15-LOX-1 transcriptional activation. Knock down of NuRD key components (for example, MTA1 and HDAC1) by small interfering RNA (siRNA) activated 15-LOX-1 transcription, as measured by luciferase reporter assays in stably transfected SW480 cells with the 15-LOX-1 promoter construct of the -391, but not the -120 region. Relative to expression in normal tissue, MTA1 expression in colorectal cancer mucosa from colorectal cancer patients was negatively related to 15-LOX-1 expression. Thus, our results show that NuRD contributes to 15-LOX-1 transcription suppression in colon cancer cells and that HDACIs can inhibit NuRD recruitment to a promoter to activate gene transcription, as in the case of 15-LOX-1.

Unconscious fear influences emotional awareness of faces and voices

Nonconscious recognition of facial expressions opens an intriguing possibility that two emotions can be present together in one brain with unconsciously and consciously perceived inputs interacting. We investigated this interaction in three experiments by using a hemianope patient with residual nonconscious vision. During simultaneous presentation of facial expressions to the intact and the blind field, we measured interactions between conscious and nonconsciously recognized images. Fear-specific congruence effects were expressed as enhanced neuronal activity in fusiform gyrus, amygdala, and pulvinar. Nonconscious facial expressions also influenced processing of consciously recognized emotional voices. Emotional congruency between visual and an auditory input enhances activity in amygdala and superior colliculus for blind, relative to intact, field presentation of faces. Our findings indicate that recognition of fear is mandatory and independent of awareness. Most importantly, unconscious fear recognition remains robust even in the light of a concurrent incongruent happy facial expression or an emotional voice of which the observer is aware.

Toenail selenium concentrations and bladder cancer risk in women and men

Prediagnostic selenium concentrations measured in archived toenails were inversely associated with bladder cancer risk in women (P for trend = 0.02), but not in men, in a nested case-control study of 338 cases and 341 matched controls. These findings may be due to chance and more studies are needed to determine whether associations between selenium and bladder cancer risk differ by sex.

Functional dissociation of amygdala-modulated arousal and cognitive appraisal, in Turner syndrome

The amygdala is preferentially activated by facial expressions of fear. Right and left amygdala are hypothesized to play distinct, but complementary, roles that influence somatic and cognitive responses to facial expressions. Right amygdala activation is linked to autonomic arousal, and thus indirectly influences left hemisphere cognitive processing centres. Left amygdala activation is more closely associated with cognitive processing and differentiation of facial emotions. A double-dissociation between the functions of left and right amygdala is implied by lesion studies but supportive evidence is inconsistent, partly because patients with structural anteromedial temporal anomalies have experienced variable surgical procedures. A functional dissociation can be demonstrated between arousal and the cognitive appraisal of fearful faces in the condition of X-monosomy or Turner syndrome. Previous research found Turner syndrome women of normal verbal intelligence are seriously impaired in their ability cognitively to differentiate fearful from other facial expressions but they acquire fear conditioning normally, with enhanced autonomic responses. These findings supported the dissociation hypothesis, which was formally tested in a study of 12 X-monosomic and 12 control females who participated in functional magnetic resonance imaging during which simultaneous skin conductance recordings were acquired. Faces depicting fear or neutral emotions were presented to both case and control subjects in random order. Arousal to (fearful-neutral) faces was associated with transiently increased skin conductance responses and bilateral amygdala activation in both groups, but X-monosomic females had proportionately greater--and more persistent--right amygdala activation than controls. In both groups, cognitive accuracy correlated positively with differential activity of left fusiform gyrus. There was a significant correlation between the left fusiform and left medial amygdala activation only in normal females, and only in them did differential SCRs (to fearful-neutral faces) correlate positively with left fusiform responses. Arousal and cognitive appraisal functions of the amygdala can thus be functionally dissociated. X-monosomy selectively impairs explicit recognition of fearful faces in the presence of normal or enhanced autonomic reactivity, and is associated with a functional dissociation of activity in left amygdala and left fusiform gyrus. These findings imply X-linked genes are essential for binding somatic responses to the cognitive appraisal of emotional stimuli.

A case--control study of selenium in nails and prostate cancer risk in British men

In view of the experimental evidence suggesting that the micronutrient selenium reduces prostate cancer risk, we investigated the association between the selenium level in fingernails, a measure of long-term selenium intake, and prostate cancer risk in a case–control study among 656 British men, conducted in 1989–1992. Nail clippings were taken at the time of recruitment and selenium concentration, measured using neutron activation techniques, was successfully assayed for 300 case–control pairs and varied six-fold among the controls (0.59 p.p.m.; interquartile range, 0.50–0.71 p.p.m.). Nail selenium concentration was not significantly associated with prostate cancer risk: men in the highest quartile of nail selenium had a slightly increased risk compared with men in the lowest quartile (OR 1.24, 95 CI, 0.73–2.10); for advanced prostate cancer, men in the highest quartile had a slightly reduced risk compared with men in the lowest quartile (OR 0.78, 95% CI, 0.27–2.25). These results suggest that selenium is not strongly associated with prostate cancer risk in British men.

Dissociable amygdala and orbitofrontal responses during reversal fear conditioning

The neural mechanisms underlying the persistence and plasticity of human emotional learning are unknown. Here we describe dissociable neural responses in amygdala and orbitofrontal cortex during acquisition and reversal of discriminatory fear conditioning. During acquisition, increased responses in bilateral amygdala were elicited by a face stimulus (A = CS+) predictive of an aversive noise compared to another nonpredictive face (B = CS-). With subsequent reversal of the conditioning contingency, face B (new CS+) elicited enhanced responses in right orbitofrontal cortex, while face A (old CS+) continued to evoke increased responses in right ventral amygdala. Thus, while orbitofrontal cortex exhibited rapid reversal of acquired fear responses, ventral amygdala showed a persistent, nonreversing "memory" for previous fear-related stimulus associations.

Radioactive waste forms stabilized by ChemChar gasification: characterization and leaching behavior of cerium, thorium, protactinium, uranium, and neptunium

The uses of a thermally reductive gasification process in conjunction with vitrification and cementation for the long-term disposal of low level radioactive materials have been investigated. gamma-ray spectroscopy was used for analysis of carrier-free protactinium-233 and neptunium-239 and a stoichiometric amount of cerium (observed cerium-141) subsequent to gasification and leaching, up to 48 days. High resolution ICP-MS was used to analyze the cerium, thorium, and uranium from 46 to 438 days of leaching. Leaching procedures followed the guidance of ASTM Procedure C 1220-92, Standard Test Method for Static Leaching of Monolithic Waste Forms for Disposal of Radioactive Waste. The combination of the thermally reductive pretreatment, vitrification and cementation produced a highly non-leachable form suitable for long-term disposal of cerium, thorium, protactinium, uranium, and neptunium.

The relationship between amalgam restorations and mercury levels in male dentists and nondental health professionals

OBJECTIVES

The objectives of this study were: (1) to compare the mercury levels in general dentists with the mercury levels in other health professionals using toenail clippings as a biomarker, (2) to identify risk factors associated with high mercury levels, and (3) to compare practice characteristics of dentists with high and low mercury levels.

METHODS

A sample of 579 men was randomly selected from the 33,737 men participating in the Health Professionals Follow-up Study who had provided toenail samples in 1987. A questionnaire was sent to these male subjects in 1991 to obtain information on fish consumption, toothbrushing frequency, number of teeth, number of amalgam restorations, general practice or specialty status, number of amalgam restorations placed and removed per week, mercury storage and handling procedures, and mercury spillage incidents. A measure of long-term mercury exposure was obtained from toenail samples using neutron activation analysis for the 410 respondents (71% response rate). The 90th percentile mercury level in toenails (0.88 ppm) was selected as the threshold for elevated toenail mercury level.

RESULTS

No relationship was found between the number of dental amalgams and toenail mercury levels among general dentists, dental specialists, and nondental health professionals. General dentists were found to have more than twice the level of mercury in toenails than nondental health professionals (mean level = 0.94 vs 0.45) and 60 percent higher than dental specialists (mean = 0.59). The combined use of disposable capsules and water storage of scrap amalgam appeared to reduce the risk of elevated mercury levels. Regardless of professional status, consumption of tuna and saltwater fish were the primary exposure factors that were positively associated with toenail mercury levels.

CONCLUSIONS

As shown by the associations with dental profession and fish consumption, the mercury content of toenails is a stable biomarker of cumulative long-term mercury exposure. The lack of association between nail mercury levels and number of amalgam restorations suggests that avoidance of mercury amalgam restorative materials cannot be justified by the presence of mercury released from dental amalgams.

Severe panniculitis caused by homozygous ZZ alpha1-antitrypsin deficiency treated successfully with human purified enzyme (Prolastin)

Severe panniculitis caused by alpha1-antitrypsin deficiency is very rare even though the ZZ phenotype occurs in 1 : 3500 of the population of northern Europe. We describe a 33-year-old woman with rapidly progressing panniculitis and extensive skin necrosis with multiple life-threatening complications. Initial treatment followed by maintenance therapy with human purified enzyme (Prolastin, Bayer, Bridgend, U.K.) has been life-saving.

Human amygdala responses to fearful eyes

Fearful facial expressions evoke increased neural responses in human amygdala. We used event-related fMRI to investigate whether eye or mouth components of a fearful face are critical in evoking this increased amygdala activity. In addition to prototypical fearful (FF) and neutral (NN) faces, subjects viewed two types of chimerical face: fearful eyes combined with a neutral mouth (FN), and neutral eyes combined with a fearful mouth (NF). FE faces evoked specific responses in left anterior amygdala. FN faces evoked responses in bilateral posterior amygdala and superior colliculus. Responses in right amygdala, superior colliculus, and pulvinar exhibited significant time x condition interactions with respect to faces with fearful eyes (FF, FN) vs neutral eyes (NF, NN). These data indicate that fearful eyes alone are sufficient to evoke increased amygdala activity. In addition, however, left amygdala displayed discriminatory responses to fearful eyes in different configural contexts (i.e., in FF and FN faces). These results suggest, therefore, that human amygdala responds to both feature-specific and configural aspects of fearful facial expressions.

David Samwell (1751-98): surgeon on the Discovery

David Samwell, born in North Wales, was surgeon on the Discovery during the third and last voyage of Captain James Cook. Samwell wrote a biography of Cook and was a distinguished poet. He also served on several more voyages, retiring from the sea aged 45.

Immunohistochemical and histopathologic features of 14 malignant fibrous histiocytomas from Flat-Coated Retrievers

Flat-Coated Retrievers seem to be at increased risk of developing soft-tissue sarcomas, and undifferentiated round cell or spindle cell sarcomas account for approximately 59% of sarcomas in the breed. In an attempt to classify these tumors further, formalin-fixed, paraffin-embedded sections from 14 undifferentiated sarcomas from Flat-Coated Retrievers were reviewed and examined with a panel of histologic and immunohistochemical stains. The panel included vimentin, desmin, Myo D1, smooth muscle actin, cytokeratin, S100, von Willebrand factor (factor VIII), Mac 387, CD3, major histocompatibility complex (MHC) class II, and CD79a. The majority of the sarcomas showed greater than 70% staining for MHC class II. We conclude that these undifferentiated sarcomas in Flat-Coated Retrievers belong to a spectrum of tumors with varying proportions of characteristic cell types and morphologic features, some of which fit the diagnostic criteria for malignant fibrous histiocytoma. Many of these sarcomas seem to have a significant myofibroblast component and a mild or moderate T cell infiltrate but the precise cell lineage is still uncertain.

Anatomical site-specific response to DNA damage is related to later tumor development in the rat azoxymethane colon carcinogenesis model

There is now general agreement that the etiology of proximal and distal colon cancers may differ, thus prompting renewed interest in understanding anatomical site-specific molecular mechanisms of tumor development. Using a 2x2x2 factorial design with male Sprague-Dawley rats (corn oil, fish oil; pectin, cellulose; plus or minus azoxymethane injection) we found a greater than 2-fold difference (P < 0.001) in tumor incidence proximally versus distally (prox/dist ratio: corn oil, 2.25; fish oil, 2.61). The purpose of the present study was to determine if the higher degree of proximal versus distal tumors in our model system could be accounted for by differences between these two sites in initial DNA damage, response to that damage or an effect of diet at one site but not the other. DNA damage was assessed by quantitative immunohistochemistry of O(6)-methylguanine adducts; repair by measurement of O(6)-methylguanine-DNA alkyltransferase and removal was determined by measurement of targeted apoptosis. Although overall initial DNA damage was similar at both sites, in the distal colon there was a greater expression of repair protein (P < 0.001) and a greater degree of targeted apoptosis (P < 0.0001). There was also a reduction in DNA damage in the distal colon of rats consuming fish oil. Together, these results suggest that the lower tumor incidence in the distal colon may be a result of the capacity to deal with initial DNA damage by the distal colon, as compared with the proximal colon. Therefore, the determination of site-specific mechanisms in tumor development is important because distinct strategies may be required to protect against cancer at different sites.

Expression and localization of IL-1beta mRNA is interrelated with cytoskeletal rearrangement in monocytes stimulated by adherence: a light microscopy in situ hybridization study

Differences in IL-1beta mRNA expression, stability and translation between non-adherent monocytes and those stimulated by adherence suggest that cytokine regulation is coupled to the function and assembly of cytoskeletal structures. In situ hybridization studies were performed to visualize expression and positioning of IL-1beta mRNA in adherently cultivated monocytes. IL-1beta mRNA expression was heterogeneous with high transcript levels found in spread or polarized cells. Transcripts were compartmentalized to the perinuclear region in spread cells, and partially redistributed with polarization. In contrast to mRNA distribution in other motile cell populations, IL-1beta mRNA did not localize to the distal or proximal actin cytoskeleton. Perinuclear confinement of transcripts required intact actin microfilaments. Treatment with cytoskeleton disruption and detergent extraction suggested that most non-translated IL-1beta mRNA was associated with intermediate filaments. In monocytes stimulated by LPS, IL-1beta, but not IL-1Ra transcripts were redistributed and partially associated, yet not bound to actin microfilaments. The present study demonstrates that IL-1beta mRNA expression and localization in adherent monocytes is interrelated with the cytoskeletal rearrangement upon adherence, spreading and polarization.

Mineral content of calcified tissues in cystic fibrosis mice

Although abnormal hard tissue mineralization is a recognized complication of cystic fibrosis (CF), the pathogenesis leading from the defective cystic fibrosis transmembrane conductance regulator (CFTR) protein is poorly understood. We hypothesized that CFTR plays a direct role in the mineralization of bone and teeth and tested the hypothesis using CF mouse models [CFTR(-) mice]. In vivo measurements by dual-emission X-ray absorpitometry (DEXA) indicated that bone mineral density (BMD) was reduced in CF mice as compared to gender-matched littermates. However, no change was evident after correction of BMD for the covariant of body weight. The latter finding was confirmed in isolated femurs and nasal bones by standard dry-ashing and instrumental neutron activation analysis (INAA). INAA of the continuously growing hypsodont incisor teeth from CFTR(-) mice revealed reduced Ca and normal P in the enamel layer--a finding consistent with changes in the deciduous teeth of CF children. Interestingly, enamel fluoride was increased in the CFTR(-) incisors and may associate with abnormal enamel crystallite formation. The iron content of the incisor enamel was reduced, explaining the loss of yellow pigmentation in CFTR(-) incisors. In contrast to the incisors, the mineral content of the slow-growing brachydont molar teeth was not different between CFTR(-) and CFTR(+) mice. It was concluded that CFTR does not play a direct role in the mineralization of bones or brachydont teeth in mice. Functional CFTR is apparently required for normal mineralization of the hypsodont incisors. However, multiple changes in the mineral composition of the CF incisors suggest an indirect role for CFTR, perhaps by maintaining a normal salivary environment for continuous tooth eruption.

Neural activity associated with episodic memory for emotional context

To address the question of which brain regions subserve retrieval of emotionally-valenced memories, we used event-related fMRI to index neural activity during the incidental retrieval of emotional and non-emotional contextual information. At study, emotionally neutral words were presented in the context of sentences that were either negatively, neutrally or positively valenced. At test, fMRI data were obtained while participants discriminated between studied and unstudied words. Recognition of words presented in emotionally negative relative to emotionally neutral contexts was associated with enhanced activity in right dorsolateral prefrontal cortex, left amygdala and hippocampus, right lingual gyrus and posterior cingulate cortex. Recognition of words from positive relative to neutral contexts was associated with increased activity in bilateral prefrontal and orbitofrontal cortices, and left anterior temporal lobe. These findings suggest that neural activity mediating episodic retrieval of contextual information and its subsequent processing is modulated by emotion in at least two ways. First, there is enhancement of activity in networks supporting episodic retrieval of neutral information. Second, regions known to be activated when emotional information is encountered in the environment are also active when emotional information is retrieved from memory.

Pharmacological modulation of behavioral and neuronal correlates of repetition priming

In this experiment we address the pharmacological modulation of repetition priming, a basic form of learning, using event-related functional magnetic resonance imaging. We measured brain activity in a word-stem completion paradigm in which, before study, volunteers were given either placebo, lorazepam (2 mg orally), or scopolamine (0.4 mg, i.v.). Relative to placebo, both drugs attenuated the behavioral expression of priming. Repetition was associated with a decreased neuronal response in left extrastriate, left middle frontal, and left inferior frontal cortices in the placebo group. Both drugs abolished these "repetition suppression" effects. By showing a concurrence of behavioral and neuronal modulations, the results suggest that GABAergic and cholinergic systems influence the neuronal plasticity necessary for repetition priming.

Iodine and thyroid cancer risk among women in a multiethnic population: the Bay Area Thyroid Cancer Study

Research on the relationship between iodine exposure and thyroid cancer risk is limited, and the findings are inconclusive. In most studies, fish/shellfish consumption has been used as a proxy measure of iodine exposure. The present study extends this research by quantifying dietary iodine exposure as well as incorporating a biomarker of long-term (1 year) exposure, i.e., from toenail clippings. This study is conducted in a multiethnic population with a wide variation in thyroid cancer incidence rates and substantial diversity in exposure. Women, ages 20-74, residing in the San Francisco Bay Area and diagnosed with thyroid cancer between 1995 and 1998 (1992-1998 for Asian women) were compared with women selected from the general population via random digit dialing. Interviews were conducted in six languages with 608 cases and 558 controls. The established risk factors for thyroid cancer were found to increase risk in this population: radiation to the head/neck [odds ratio (OR), 2.3; 95% confidence interval (CI), 0.97-5.5]; history of goiter/nodules (OR, 3.7; 95% CI, 2.5-5.6); and a family history of proliferative thyroid disease (OR, 2.5; 95% CI, 1.6-3.8). Contrary to our hypothesis, increased dietary iodine, most likely related to the use of multivitamin pills, was associated with a reduced risk of papillary thyroid cancer. This risk reduction was observed in "low-risk" women (i.e., women without any of the three established risk factors noted above; OR, 0.53; 95% CI, 0.33-0.85) but not in "high-risk" women, among whom a slight elevation in risk was seen (OR, 1.4; 95% CI, 0.56-3.4). However, no association with risk was observed in either group when the biomarker of exposure was evaluated. In addition, no ethnic differences in risk were observed. The authors conclude that iodine exposure appears to have, at most, a weak effect on the risk of papillary thyroid cancer.

CpG island methylation in colorectal adenomas

Methylation of cytosines in CpG islands silences gene expression. CpG island methylator phenotype (CIMP) in colorectal cancers is characterized by abnormal methylation of multiple CpG islands including those in several tumor suppressor genes such as p16, hMLH1, and THBS1. CpG island methylation has not been well characterized in adenomas. We evaluated methylation status at p16, MINT2, and MINT31 loci, which are frequently methylated in colorectal carcinomas, in 108 colorectal adenomas from a prospective study of 50 patients without cancer. Methylation at one or more loci was present in 48% (52 of 108) of adenomas with 25% (19 of 76) CIMP-high (two or more methylated loci) and 32% (24 of 76) CIMP-low (one methylated locus). The p16 gene was methylated in 27% (19 of 71) of adenomas. Methylation status of different adenomas from the same patient was not correlated (odds ratio, 0.93; P = 0.77). Adenomas with tubulovillous or villous histology were frequently methylated: 73% (17 of 26) versus 41% (35 of 85) of tubular adenomas (odds ratio, 3.46; P = 0.02). High levels of microsatellite instability were more frequent in adenomas without methylation (13% versus 2%; odds ratio, 8.48; P = 0.05). Our results indicate that methylation plays an important role early in colorectal tumorigenesis. CpG island methylation is more common in adenomas with tubulovillous/villous histology, a characteristic associated with more frequent predisposition to invasive carcinoma. Methylation is distinct from microsatellite instability and develops in individual adenomas rather than resulting from a field defect in an individual patient.

Dietary n-3 polyunsaturated fatty acids modulate purified murine T-cell subset activation

Studies in humans and murine disease models have clearly shown dietary fish oil to possess anti-inflammatory properties, apparently mediated by the n-3 polyunsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). To determine the mechanisms by which dietary EPA and DHA modulate mouse T-cell activation, female C57BL/6 mice were fed diets containing either 2% safflower oil (SAF), 2% fish oil (FO), or a 2% purified EPA/DHA ethyl ester mixture for 14 days. Splenic CD4 T cells ( approximately 90% purity) or CD8 T cells ( approximately 85% purity) were incubated with agonists which act at the plasma membrane receptor level [anti(alpha)-CD3/anti(alpha)-CD28], the intracellular level (PMA/Ionomycin), or at both the receptor and intracellular levels (alphaCD3/PMA). CD4 T cells stimulated with alphaCD3/alphaCD28 or PMA/Ionomycin proliferated and produced principally IL-2 (i.e. a Th1 phenotype), whereas the proliferation of CD4 T cells stimulated with alphaCD3/PMA was apparently driven principally by IL-4 (i.e. a Th2 phenotype). The IL-4 driven proliferation of putative Th2 CD4 cells was enhanced by dietary n-3 fatty acids (P = 0.02). Conversely, IL-2 production by alphaCD3/alpha CD28-stimulated CD4 T cells was reduced in FO-fed animals (P < 0.0001). The alphaCD3/alphaCD28-stimulated CD8 cells cultured from FO-fed animals exhibited a significant decrease (P < 0.05) in proliferation. There were no dietary effects seen in alphaCD3/PMA-stimulated CD8 cells, which produced both IL-2 and IL-4, or in PMA/Ionomycin-stimulated CD8 cells, which produced principally IL-2. These data suggest that dietary n-3 fatty acids down-regulated IL-2 driven CD4 and CD8 activation, while up-regulating the activation of the Th2 CD4 T-cell subset. Thus, the anti-inflammatory effects of n-3 fatty acids may result in both the direct suppression of IL-2-induced Th1 cell activation and the indirect suppression of Th1 cells by the enhanced cross-regulatory function of Th2 cells.

Crossmodal binding of fear in voice and face

In social environments, multiple sensory channels are simultaneously engaged in the service of communication. In this experiment, we were concerned with defining the neuronal mechanisms for a perceptual bias in processing simultaneously presented emotional voices and faces. Specifically, we were interested in how bimodal presentation of a fearful voice facilitates recognition of fearful facial expression. By using event-related functional MRI, that crossed sensory modality (visual or auditory) with emotional expression (fearful or happy), we show that perceptual facilitation during face fear processing is expressed through modulation of neuronal responses in the amygdala and the fusiform cortex. These data suggest that the amygdala is important for emotional crossmodal sensory convergence with the associated perceptual bias during fear processing, being mediated by task-related modulation of face-processing regions of fusiform cortex.

Involvement of human amygdala and orbitofrontal cortex in hunger-enhanced memory for food stimuli

We used positron emission tomography to measure regional cerebral blood flow (rCBF) in 10 healthy volunteers performing a recognition memory task with food and non-food items. The biological salience of the food stimuli was manipulated by requiring subjects to fast before the experiment and eat to satiation at fixed time points during scanning. All subjects showed enhanced recognition of food stimuli (relative to non-food) in the fasting state. Satiation significantly reduced the memory advantage for food. Left amygdala rCBF covaried positively with recognition memory for food items, whereas rCBF in right anterior orbitofrontal cortex covaried with overall memory performance. Right posterior orbitofrontal rCBF covaried positively with hunger ratings during presentation of food items. Regression analysis of the neuroimaging data revealed that left amygdala and right lateral orbitofrontal rCBF covaried as a function of stimulus category (i.e., food vs non-food). These results indicate the involvement of amygdala and discrete regions of orbitofrontal cortex in the integration of perceptual (food), motivational (hunger), and cognitive (memory) processes in the human brain.

Differential extrageniculostriate and amygdala responses to presentation of emotional faces in a cortically blind field

Patient G.Y. is able to discriminate emotional facial expressions presented in his blind (right) hemifield despite an extensive lesion of the corresponding (left) striate cortex. One proposal is that this residual ability (affective "blindsight") depends on a subcortical visual pathway comprising the superior colliculus, posterior (extrageniculate) thalamus and amygdala. Here we report differential amygdala responses in G.Y. to presentation of fearful and fear-conditioned faces in his blind (right) hemifield. These amygdala responses exhibited condition-dependent covariation with neural activity in the posterior thalamus and superior colliculus. Our results provide further evidence that an extrageniculostriate (colliculo-thalamo-amygdala) neural pathway can process fear-related stimuli independently of both the striate cortex and normal phenomenal visual awareness.

Nonsteroidal anti-inflammatory drugs induce apoptosis in esophageal cancer cells by restoring 15-lipoxygenase-1 expression

In previous studies, we have found that expression of 15-lipoxygenase-1 (15-LOX-1) and its main product, 13-S-hydroxyoctadecadienoic acid, are decreased in human colorectal cancers and that nonsteroidal anti-inflammatory drugs (NSAIDs) can therapeutically induce 15-LOX-1 expression to trigger apoptosis in human colorectal cancer cells. NSAIDs similarly induce apoptosis in esophageal cancer cells, although the mechanisms of these effects remain to be defined. In the present study, we tested whether 15-LOX-1 is down-regulated in human esophageal cancers using paired normal and tumor human surgical samples and whether NSAIDs can up-regulate 15-LOX-1 to restore apoptosis in esophageal cancer cells. We found that: (a) 15-LOX-1 was down-regulated in human esophageal carcinomas; (b) NSAIDs induced 15-LOX-1 expression during apoptosis in esophageal cancer cells; and (c) 15-LOX-1 inhibition suppressed NSAID-induced apoptosis, which was restored by 13-S-hydroxyoctadecadienoic acid but not by its parent compound, linoleic acid. These findings demonstrate that 15-LOX-1 is down-regulated in human esophageal carcinomas and that NSAIDs induce apoptosis in esophageal cancer cells via up-regulation of 15-LOX-1. They also support the concept that the loss of the proapoptotic role of 15-LOX-1 in epithelial cancers is not limited to human colorectal cancers.

Parallel neural responses in amygdala subregions and sensory cortex during implicit fear conditioning

We used event-related fMRI to measure neural activity in volunteer subjects during acquisition of an implicit association between a visual conditioned stimulus (CS+) (angry face) and an auditory unconditioned stimulus (UCS) (aversive, loud noise). Three distinct functional regions were identified within left amygdala: a UCS (noise)-related lateral region, a CS+-related ventral region, and a dorsal region where CS+-related responses changed progressively across the learning session. Differential neural responses to the visual CS+ were also evoked in extrastriate and auditory cortices. Our results indicate that learning an association between biologically salient stimuli of different sensory modalities involves parallel changes of neural activity in segregated amygdala subregions and unimodal sensory cortices.

Skin cancer risk in relation to toenail arsenic concentrations in a US population-based case-control study

Arsenic is a known carcinogen specifically linked to skin cancer occurrence in regions with highly contaminated drinking water or in individuals who took arsenic-containing medicines. Presently, it is unknown whether such effects occur at environmental levels found in the United States. To address this question, the authors used data collected on 587 basal cell and 284 squamous cell skin cancer cases and 524 controls interviewed as part of a case-control study conducted in New Hampshire between 1993 and 1996. Arsenic was determined in toenail clippings using instrumental neutron activation analysis. The odds ratios for squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) were close to unity in all but the highest category. Among individuals with toenail arsenic concentrations above the 97th percentile, the adjusted odds ratios were 2.07 (95% confidence interval (CI): 0.92, 4.66) for SCC and 1.44 (95% CI: 0.74, 2.81) for BCC, compared with those with concentrations at or below the median. While the risks of SCC and BCC did not appear elevated at the toenail arsenic concentrations detected in most study subjects, the authors cannot exclude the possibility of a dose-related increase at the highest levels of exposure experienced in the New Hampshire population.

Inhibition of the calcium-dependent tyrosine kinase (CADTK) blocks monocyte spreading and motility

Freshly isolated peripheral blood monocytes lack focal adhesion kinase (p125(FAK)) but activate a second member of this kinase family, calcium-dependent tyrosine kinase (CADTK; also known as Pyk2/CAKbeta/RAFTK/FAK2), upon adhesion or stimulation with chemokines. To study the role of CADTK in monocyte adherence and motility, we performed immunocytochemical localization that showed CADTK at the leading edge and ruffling lamellipodial structures in freshly isolated, adhered human monocytes. We next introduced CADTK/CAKbeta-related non-kinase (CRNK), the C-terminal noncatalytic domain of CADTK, into monocytes by electroporation and showed that it inhibited CADTK autophosphorylation. Introduction of the fusion protein glutathione S-transferase (GST)-CRNK also reduced (i) cell spreading, as reflected in a reduced cell area 30 min after adhesion, (ii) adhesion-induced phosphotyrosine increases and redistribution into lamellipodia, and (iii) adhesion-induced extracellular signal-regulated protein kinase (ERK) activation. In control experiments, introduction of GST or GST-C3 transferase (an inhibitor of RhoA GTPase activity) by electroporation did not affect these parameters. Monocytes adhered in the presence of autologous serum were highly motile even after introduction of GST (83% motile cells). However, only 26% of monocytes with introduced GST-CRNK were motile. In contrast, GST-CRNK-treated monocytes were fully capable of phagocytosis and adhesion-induced cytokine gene induction, suggesting that CADTK is not involved in these cellular activities and that GST-CRNK introduction does not inhibit global monocyte functions. These results suggest that CADTK is crucial for the in vitro monocyte cytoskeletal reorganization necessary for cell motility and is likely to be required in vivo for recruitment to sites of inflammation.

Association between alpha-tocopherol, gamma-tocopherol, selenium, and subsequent prostate cancer

BACKGROUND

Selenium and alpha-tocopherol, the major form of vitamin E in supplements, appear to have a protective effect against prostate cancer. However, little attention has been paid to the possible role of gamma-tocopherol, a major component of vitamin E in the U.S. diet and the second most common tocopherol in human serum. A nested case-control study was conducted to examine the associations of alpha-tocopherol, gamma-tocopherol, and selenium with incident prostate cancer.

METHODS

In 1989, a total of 10,456 male residents of Washington County, MD, donated blood for a specimen bank. A total of 117 of 145 men who developed prostate cancer and 233 matched control subjects had toenail and plasma samples available for assays of selenium, alpha-tocopherol, and gamma-tocopherol. The association between the micronutrient concentrations and the development of prostate cancer was assessed by conditional logistic regression analysis. All statistical tests were two-sided.

RESULTS

The risk of prostate cancer declined, but not linearly, with increasing concentrations of alpha-tocopherol (odds ratio (highest versus lowest fifth) = 0.65; 95% confidence interval = 0.32--1.32; P(trend) =.28). For gamma-tocopherol, men in the highest fifth of the distribution had a fivefold reduction in the risk of developing prostate cancer than men in the lowest fifth (P:(trend) =.002). The association between selenium and prostate cancer risk was in the protective direction with individuals in the top four fifths of the distribution having a reduced risk of prostate cancer compared with individuals in the bottom fifth (P(trend) =.27). Statistically significant protective associations for high levels of selenium and alpha-tocopherol were observed only when gamma-tocopherol concentrations were high.

CONCLUSIONS

The use of combined alpha- and gamma- tocopherol supplements should be considered in upcoming prostate cancer prevention trials, given the observed interaction between alpha-tocopherol, gamma-tocopherol, and selenium.

Histopathological survey of neoplasms in flat-coated retrievers, 1990 to 1998

Over the period from March 1990 to December 1998, veterinary surgeons in general practice were invited to submit tissues suspected of being neoplastic which had been removed from flat-coated retrievers. When possible, pedigree details were obtained from the owners. In addition, data were collected from flat-coated retrievers known to have suffered from a neoplastic condition and for which a histopathological report was available. A total of 1023 submissions was obtained from 782 dogs. These included 165 non-neoplastic lesions (16 per cent), 447 benign samples (44 per cent) and 411 malignant samples (40 per cent). Soft tissue sarcomas accounted for 55 per cent of the malignant samples (26 per cent of all tumour samples and 22 per cent of all submissions) with 63 per cent of them being diagnosed as undifferentiated. Carcinomas accounted for 20 per cent of malignant samples (8 per cent of all submissions). Of the benign tumours, cutaneous histiocytoma was the most common diagnosis (48 per cent of benign tumours, 25 per cent of all tumours and 21 per cent of all submissions).

Morphodensitometric analysis of protein kinase C beta(II) expression in rat colon: modulation by diet and relation to in situ cell proliferation and apoptosis

We have recently demonstrated that overexpression of PKC beta(II) renders transgenic mice more susceptible to carcinogen-induced colonic hyperproliferation and aberrant crypt foci formation. In order to further investigate the ability of PKC beta(II) to modulate colonocyte cytokinetics, we determined the localization of PKC beta(II) with respect to cell proliferation and apoptosis along the entire colonic crypt axis following carcinogen and diet manipulation. Rats were provided diets containing either corn oil [containing n-6 polyunsaturated fatty acids (PUFA)] or fish oil (containing n-3 PUFA), cellulose (non-fermentable fiber) or pectin (fermentable fiber) and injected with azoxymethane (AOM) or saline. After 16 weeks, an intermediate time point when no macroscopic tumors are detected, colonic sections were utilized for immunohistochemical image analysis and immunoblotting. Cell proliferation was measured by incorporation of bromodeoxyuridine into DNA and apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling. In the distal colon, PKC beta(II) staining was localized to the upper portion of the crypt. In comparison, proximal crypts had more (P < 0.05) staining in the lower tertile. AOM enhanced (P < 0.05) PKC beta(II) expression in all regions of the distal colonic crypt (upper, middle and lower tertiles). There was also an interaction (P < 0.05) between dietary fat and fiber on PKC beta(II) expression (corn/pectin > fish/cellulose, fish/pectin > corn/cellulose) in all regions of the distal colonic crypt. With respect to colonic cell kinetics, proliferation paralleled the increase in PKC beta(II) expression in carcinogen-treated animals. In contrast, apoptosis at the lumenal surface was inversely proportional to PKC beta(II) expression in the upper tertile. These results suggest that an elevation in PKC beta(II) expression along the crypt axis in the distal colon is linked to enhancement of cell proliferation and suppression of apoptosis, predictive intermediate biomarkers of tumor development. Therefore, select dietary factors may confer protection against colon carcinogenesis in part by blocking carcinogen-induced PKC beta(II) expression.