Metabolic changes associated with two endocrine abnormalities in dogs: elevated fructosamine and low thyroxine.

INTRODUCTION: Metabolomics studies in canine endocrine abnormalities are sparse and basic information on these abnormalities must be generated. OBJECTIVES: To characterize the metabolic changes associated with elevated fructosamine, reflecting poor glycemic control, and low thyroxine, a thyroid hormone controlling metabolism. METHODS: Leftovers of clinical serum samples; 25 controls, 79 high fructosamine, and 47 low thyroxine, were analyzed using 1H NMR and differences were evaluated using Firth logistic regression. RESULTS: Both high fructosamine and low thyroxine were associated with changes in concentrations of multiple metabolites, including glycoprotein acetyls and lipids. CONCLUSION: These findings suggest promising makers for further research and clinical validation.

Anti-Müllerian hormone concentrations in female rabbits and its relation to spay status, pseudopregnancy and ovarian follicle numbers.

Anti-Müllerian hormone (AMH), known for its role during foetal sexual differentiation, is secreted by the Sertoli cells in males and the granulosa cells in females during post-natal life. As serum AMH concentrations correlate with follicle numbers, AMH is utilized as a marker of ovarian reserve in many species. In dogs and cats, AMH is used as a diagnostic tool to determine spay or neuter status. In the available literature, no research regarding serum AMH levels in rabbits has been published yet. The objectives of the present study were to (1) measure serum AMH concentrations in female rabbits and investigate the value of AMH as a diagnostic tool to differentiate between spayed and intact does and (2) relate measured AMH levels to pseudopregnancy and ovarian follicle numbers. For AMH measurement, serum samples were obtained from sexually intact (n = 64) and spayed (n = 22) female rabbits. Spayed does were of various breeds; intact rabbits were Zika hybrid rabbits. In the intact does, AMH measurement was complemented by determination of progesterone levels, gynaecological examination and histopathological evaluation of the uterus and ovaries, including follicle counts. Serum AMH and progesterone concentrations were measured using a human-based chemiluminescence immunoassay (CLIA) and an enzyme-linked fluorescence assay (ELFA), respectively. Depending on progesterone levels, sexually intact does were classified into follicular (n = 52) or luteal phase (n = 12). Median serum AMH levels were 1.53 ng/ml (range 0.77-3.36 ng/ml) in intact and 0.06 ng/ml (range ≤0.01-0.23 ng/ml) in spayed does. AMH concentrations between the intact and spayed rabbits differed significantly and did not overlap (p < .001). Receiver operating characteristic (ROC) curve analysis yielded a sensitivity and specificity of 100% for a cut-off level of 0.50 ng/ml. Follicular or luteal phase had no significant influence on measured AMH levels (t = 0.061, df = 62, p = .951). While the number of secondary follicles correlated significantly with AMH concentrations (rs  = 0.410, p = .001), the number of primary or antral follicles did not (rs  = 0.241, p = .055 and rs  = 0.137, p = .281, respectively). In conclusion, a single determination of serum AMH concentrations was adequate to distinguish spayed from intact female rabbits. Among sexually intact individuals, whether does were in follicular or luteal phase had no significant influence on measured serum AMH concentrations. The relationship between small growing follicles and AMH levels as described in other species could be partially confirmed, as secondary follicles correlated significantly with AMH.

SARS-CoV-2-Specific Antibodies in Domestic Cats during First COVID-19 Wave, Europe.

We conducted a severe acute respiratory syndrome coronavirus 2 antibody seroprevalence study among >2,000 domestic cats from 4 countries during the first coronavirus disease wave in Europe. We found 4.4% seroprevalence using a virus neutralization test and 4.3% using a receptor-binding domain ELISA, demonstrating probable human-to-cat transmission.

Privacy, Early Colostrum, and Gestational Age are Associated with Exclusive Breastfeeding in Preterm and Sick Term Infants.

Our study was designed to assess the rates of exclusive breastfeeding (defined as direct breastfeeding) and the use of mother's own milk (MOM) in preterm infants and sick term infants at discharge and to identify potential influencing factors such as gestational age, early colostrum, and privacy. The study was conducted at a German level III neonatal department. All preterm and sick term infants admitted to the neonatal intensive care unit, the pediatric intensive care unit, the intermediate care unit, and the low care ward were included in the study. Infants were recruited between March and October 2015 (phase 1) and April to July 2016 (phase 2). Due to an emergency evacuation, privacy was limited during the first phase. Breastfeeding and the use of MOM were assessed daily using a self-designed score. In total, 482 infants of 452 mothers were included. More than 90% initiated breastfeeding and one-third were exclusively breastfed at discharge. Extremely immature infants and late preterm infants were less likely to be exclusively breastfed at discharge. Privacy (p<0.001) and early colostrum (p=0.002) significantly increased exclusive breastfeeding. Conclusion Extremely immature and late preterm infants were least likely to be exclusively breastfed at discharge and need special support. Interventions such as privacy and early colostrum should be promoted to increase breastfeeding.

Facilitators of Attendance and Adherence to Group-Based Physical Activity for Older Adults: A Literature Synthesis.

This review examines program features that influence attendance and adherence to group-based physical activity (PA) by older adults. Medline, PubMed, CINAHL plus, PsycINFO, and the Cochrane Library were searched for studies published from 1995-2016. Quantitative and qualitative studies investigating factors related to PA group attendance or adherence by persons aged 55 years and over were included. Searching yielded eight quantitative and 13 qualitative studies, from 2,044 titles. Quantitative findings identified social factors, instructor characteristics, PA types, class duration and frequency, and perceived PA outcomes as important for attendance and adherence, whilst qualitative studies identified settings, leadership, PA types, observable benefits, and social support factors. Studies were predominantly low- to moderate-quality. This review identified design and delivery considerations for group-based PA programs to inform best-practice frameworks and industry capacity building. Future research should use longitudinal and mixed-methods designs to strengthen evidence about facilitators of program reach and engagement.

The MOVE study: a study protocol for a randomised controlled trial assessing interventions to maximise attendance at physical activity facilities.

BACKGROUND: Physical activity is associated with a host of health benefits, yet many individuals do not perform sufficient physical activity to realise these benefits. One approach to rectifying this situation is through modifying the built environment to make it more conducive to physical activity, such as by building walking tracks or recreational physical activity facilities. Often, however, modifications to the built environment are not connected to efforts aimed at encouraging their use. The purpose of the Monitoring and Observing the Value of Exercise (MOVE) study is to evaluate the effectiveness of two interventions designed to encourage the ongoing use of a new, multi-purpose, community-based physical activity facility. METHODS/DESIGN: A two-year, randomised controlled trial with yearly survey points (baseline, 12 months follow-up, 24 months follow-up) will be conducted among 1,300 physically inactive adult participants aged 18-70 years. Participants will be randomly assigned to one of three groups: control, intervention 1 (attendance incentives), or intervention 2 (attendance incentives and tailored support following a model based on customer relationship management). Primary outcome measures will include facility usage, physical activity participation, mental and physical wellbeing, community connectedness, social capital, friendship, and social support. Secondary outcome measures will include stages of change for facility usage and social cognitive decision-making variables. DISCUSSION: This study will assess whether customer relationship management systems, a tool commonly used in commercial marketing settings, can encourage the ongoing use of a physical activity facility. Findings may also indicate the population segments among which the use of such systems are most effective, as well as their cost-effectiveness. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12615000012572 (registered 9 January 2015).

LISA Eligibility and LISA Success in Extremely Preterm Infants: A Single-Center Experience.

INTRODUCTION: Less invasive surfactant application (LISA) is associated with improved short-term outcomes in preterm infants. Data on LISA eligibility and success for infants <28 weeks of gestation are lacking. METHODS: Preterm infants <28 weeks of gestation who were born and actively treated in our tertiary care center in 2018 were included in the retrospective study. We assessed baseline characteristics, delivery room (DR) management, LISA success and complications, and short-term outcome. RESULTS: In total, 57 infants received LISA in the DR. LISA eligibility was 73% at 22 weeks, 88% at 23 weeks, and >90% at gestational ages >24 weeks. LISA was successful in 63% of infants. LISA failure was associated with increased risk for high-grade IVH (OR 17.88), death (OR 10.94), and a reduced chance for survival without complications (OR 8.75). CONCLUSION: Our report justifies LISA as a mode for surfactant application in preterm infants. It contributes to the call for studies to define risk factors for LISA failure.

Diagnostic cut-off values for the urinary corticoid:creatinine ratio for the diagnosis of canine Cushing's syndrome using an automated chemiluminescent assay.

BACKGROUND: Cushing's syndrome is one of the most common endocrinopathies in dogs. The preferred screening test for spontaneous Cushing's syndrome is the low-dose dexamethasone suppression test (LDDST). The diagnostic value of urinary cortisol:creatinine ratios (UCCR) is questionable. OBJECTIVES: The aim of this study was to determine diagnostic cut-off values for UCCR testing in comparison with LDDST as a clinical reference standard and to calculate the sensitivity and specificity. METHODS: Data from 2018 to 2020 were obtained retrospectively from a commercial laboratory. Both LDDST and UCCR were measured by automated chemiluminescent immunoassay (CLIA). The maximum interval between both tests was 14 days. The optimal cut-off value for UCCR testing was calculated by the Youden index. The sensitivity and specificity of these cut-off values for the UCCR test and LDDST were assessed by Bayesian latent class models (BLCMs). RESULTS: This study included 324 dogs with both UCCR test and LDDST results. The optimal UCCR cut-off value, calculated by the Youden index, was 47.4 × 10-6 . Any UCCR <40 × 10-6 was interpreted as a negative result, 40-60 × 10-6 as values in a gray zone, and >60 × 10-6 as positive. Using the cut-off of 60 × 10-6 , BLCM showed 91% (LDDST) and 86% (UCCR test) sensitivity and a specificity of 54% (LDDST) and 63% (UCCR test). CONCLUSIONS: Considering an 86% sensitivity and a 63% specificity, UCCR testing may be considered a first-line investigation to rule out Cushing's syndrome using CLIA analysis. Urine samples can be collected noninvasively at home by the owner, reducing the potential impact of stress.

Anti-Müllerian hormone concentrations in queens throughout the estrous cycle.

Studies in cats and dogs have proven the usefulness of anti-Müllerian hormone (AMH) as a diagnostic tool to determine the castration status or to diagnose ovarian remnant syndrome. Yet the secretion pattern of AMH over the estrous cycle in queens has not been investigated so far. Seven healthy sexually intact female cats were examined daily for signs of estrous behavior over a trial period of 4 months. Five queens showed regular estrous behavior, 1 queen was mated in her first heat and 1 queen never showed any signs of heat. To distinguish between inter-estrus and metestrus progesterone levels were determined. Serum samples for AMH and progesterone measurement were collected from the regular cycling queens in late anestrus, at several times during heat, inter-estrus and metestrus, from the mated queen during her first heat and during pregnancy, and in the acycling queen at various times during the trial period. The measured AMH values in anestrus were significantly (P < 0.05) higher than in heat (P < 0.001), metestrus (P = 0.12) and inter-estrus (P = 0.449). In anestrus the median AMH levels were 10.26 ng/ml (range 4.96 to 22.90 ng/ml), in heat 5.97 ng/ml (range 3.32- 22.96 ng/ml), in inter-estrus 10.47 (range 3.35-22.96 ng/ml) and in metestrus 6.38 ng/ml (range 4.50-10.75 ng/ml. The pregnant cat showed median AMH concentrations of 6.47 ng/ml (range 5.60-9.80 ng/ml) during her pregnancy. The acycling queen had solely low AMH values with a median concentration of 0.39 ng/ml. In conclusion there were high variations of the AMH levels among and within the individual cats and between heat cycles in the single cat. Remarkable high AMH concentrations were measured in the younger queens of the study in their first estrous cycles and also in anestrus, when less ovarian activity is expected. Further studies are necessary to emphasize the reasons for these high AMH concentrations especially in young queens.

Anti-Müllerian hormone, testosterone, and insulin-like peptide 3 as biomarkers of Sertoli and Leydig cell function during deslorelin-induced testicular downregulation in the dog.

The role of anti-Müllerian hormone (AMH) and insulin-like peptide 3 (INSL3) in male infertility is not fully understood. We used the downregulated testis as a model of gonadotropin-dependent infertility. Serum testosterone and AMH concentrations were studied in five adult male Beagles implanted (day 0) with 4.7 mg deslorelin (Suprelorin®, Virbac) (DES group). Testicular expression of LH receptor (LHR) and androgen receptor (AR), AMH, type 2 AMH receptor (AMHR2), INSL3 and its receptor (RXFP2) was evaluated 112 days (16 weeks) after deslorelin treatment by qPCR and immunohistochemistry, and compared to untreated adult (CON, n = 6) and prepubertal (PRE, n = 8) dogs. Serum testosterone concentration decreased significantly by the onset of aspermia on study day 14 (four dogs) or day 21 (one dog), and was baseline on day 105 (week 15). In contrast, serum AMH started to increase only after the onset of aspermia and reached the maximum detectable concentration of the assay by day 49-105 in individual dogs. Testicular LHR gene expression in DES was lower than in CON and PRE (P < 0.0001), while AR gene expression in DES was similar to CON and significantly higher than PRE (P < 0.0001). Testicular AMH expression in DES was intermediate compared to the lowest mRNA levels found in CON and the highest in PRE (P ≤ 0.006). AMHR2 gene expression was similar between groups. AMH protein was detected in Sertoli cells only, while AMHR2 immunoreactivity was principally detected in Leydig cells which appeared to be increased in DES. INSL3 and RXFP2 gene expression was significantly downregulated in the DES testis along with noticeably weak Leydig cell immunosignals compared to CON. In conclusion, deslorelin treatment caused testicular LH insensitivity without affecting androgen sensitivity, and de-differentiation of Sertoli and Leydig cells. In DES, upregulation of the AMH-AMHR2 feed-back loop and downregulation of the INSL3-RXFP2 feed-forward loop are paracrine-autocrine mechanisms that may additionally regulate testosterone production independent of gonadotropins. Our results support AMH and INSL3 as unique biomarkers and paracrine-autocrine regulators of testis function involved in the intimate interplay between Sertoli and Leydig cells.

Changes in anti-Müllerian hormone concentrations in bitches throughout the oestrous cycle.

Studies in female dogs proved the measurement of anti-Müllerian hormone (AMH) as a diagnostic tool to distinguish ovarioectomized from intact females or to diagnose ovarian remnant syndrome. Furthermore, its usability to diagnose a granulosa cell tumour and predict litter size was also investigated in female dogs. Although serum AMH was previously shown to increase during the transition from anoestrus to pro-oestrus in dogs, changes in AMH concentration over the entire oestrous cycle have not yet been determined. The aim of this study was to investigate the secretion pattern of AMH throughout the oestrous cycle in non-pregnant bitches. As a preliminary step, we tested our assay by measuring AMH concentrations in serum samples of 19 intact bitches (10 in anoestrus, 3 in pro-oestrus, 3 in oestrus, 3 in metoestrus) and 19 spayed females of different age and breed. For the main study, 20 healthy female dogs were examined (10 Beagles, and 10 Labrador crossbreeds, body weight 10-28 kg, age 1-6 years) during a normal oestrous cycle. Serum samples were collected in late anoestrus, at several times during pro-oestrus and oestrus, as well as 28 days and 4.5 months after ovulation. Blood collection was combined with a gynaecological examination including progesterone measurement. Serum concentration of AMH was determined using a chemiluminescence immunoassay validated for dog serum. In the preliminary test, intact bitches in various stages of the oestrous cycle had significantly higher serum AMH levels (0.19-1.45 ng/ml) than spayed females (0.01-0.06 ng/ml, P < 0.001). In cycling Beagle and Labrador crossbreed bitches participating in our main study, AMH concentrations were between 0.09 and 2.65 ng/ml with higher AMH concentrations in Beagles but overall high inter-individual and intra-individual variation. The highest AMH values were reached in the last three weeks before the onset of heat until six days before ovulation, and the lowest AMH concentrations were recorded during preovulatory oestrus in 6, metoestrus in 7 or anoestrus in 7 dogs. Serum AMH concentrations increased significantly from late anoestrus up to six days before ovulation and decreased significantly over the last three days before ovulation. A further significant decrease occurred from the last days of oestrus to metoestrus and mid anoestrus. This study shows that the used AMH assay can clearly distinguish between intact and spayed females and that the serum AMH pattern over the oestrous cycle is similar in all bitches, but with high variation among the breeds and among and within bitches. These changes in the AMH concentration are a challenge in timing serum sample collection and interpreting AMH values in bitches. Further studies are necessary to emphasize the factors influencing the AMH concentration.

Interferon gamma enhances the effectiveness of tumor necrosis factor-related apoptosis-inducing ligand receptor agonists in a xenograft model of Ewing's sarcoma.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces selective apoptosis in a variety of tumors, including most cell lines derived from Ewing's sarcoma family of tumors, an aggressive sarcoma that afflicts children and young adults. To determine the in vivo efficacy of TRAIL receptor agonists in Ewing's sarcoma family of tumors, mice with orthotopic xenografts were treated with anti-TRAIL-R2 monoclonal antibody or TRAIL/Apo2L in a model that can identify effects on both primary tumors and metastases. Administration of either agonist slowed tumor growth in 60% of animals and induced durable remissions in 11 to 19% but did not alter the incidence of metastatic disease. Response rates were not improved by concurrent doxorubicin treatment. Cells recovered from both TRAIL receptor agonist-treated and nontreated tumors were found to be resistant to TRAIL-induced death in vitro unless pretreated with interferon (IFN) gamma. This resistance coincided with a selective down-regulation of TRAIL receptor expression on tumor cells. In vivo treatment with IFNgamma increased tumor expression of TRAIL receptors and caspase 8, but did not increase the antitumor effect of TRAIL receptor agonists on primary tumors. However, IFNgamma treatment alone or in combination with a TRAIL receptor agonist significantly decreased the incidence of metastatic disease and the combination of TRAIL receptor agonist therapy with IFNgamma-mediated impressive effects on both primary tumors and metastatic disease. These data demonstrate that in vivo growth favors TRAIL resistance but that TRAIL receptor agonists are active in Ewing's sarcoma family of tumors and that the combination of TRAIL receptor agonists with IFNgamma is a potent regimen in this disease capable of controlling both primary and metastatic tumors.

Optimizing Implementation of Obesity Prevention Programs: A Qualitative Investigation Within a Large-Scale Randomized Controlled Trial.

PURPOSE: The prevalence of obesity in rural and remote areas is elevated in comparison to urban populations, highlighting the need for interventions targeting obesity prevention in these settings. Implementing evidence-based obesity prevention programs is challenging. This study aimed to investigate factors influencing the implementation of obesity prevention programs, including adoption, program delivery, community uptake, and continuation, specifically within rural settings. METHODS: Nested within a large-scale randomized controlled trial, a qualitative exploratory approach was adopted, with purposive sampling techniques utilized, to recruit stakeholders from 41 small rural towns in Australia. In-depth semistructured interviews were conducted with clinical health professionals, health service managers, and local government employees. Open coding was completed independently by 2 investigators and thematic analysis undertaken. FINDINGS: In-depth interviews revealed that obesity prevention programs were valued by the rural workforce. Program implementation is influenced by interrelated factors across: (1) contextual factors and (2) organizational capacity. Key recommendations to manage the challenges of implementing evidence-based programs focused on reducing program delivery costs, aided by the provision of a suite of implementation and evaluation resources. Informing the scale-up of future prevention programs, stakeholders highlighted the need to build local rural capacity through developing supportive university partnerships, generating local program ownership and promoting active feedback to all program partners. CONCLUSION: We demonstrate that the rural workforce places a high value on obesity prevention programs. Our results inform the future scale-up of obesity prevention programs, providing an improved understanding of strategies to optimize implementation of evidence-based prevention programs.

Investigations on the expression of cytokines in the canine corpus luteum in relation to dioestrus.

Control of luteal regression in the dog is still poorly understood. Unlike other domestic animal species, luteolysis is not prevented by hysterectomy. Indications that PGF(2alpha) may act as an endogenous luteolytic agent have been found only in pregnant animals during the prepartal decline of progesterone. Evidence from several species indicates that the immune system plays an important role in corpus luteum (Cl) function, possibly by the release of cytokines from immigrant immune cells. Hence, in the present experiment we attempted to examine the expression of cytokines in the canine Cl during the course of dioestrus (formation and regression of the Cl), using RT-PCR. Groups of 4-5 bitches were ovario-hysterectomised on days 5, 15, 25, 35, 45 and 60-80 after ovulation. Canine-specific primers for IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, TNFalpha, IFNgamma and TGFbeta1 were used. Positive and negative controls were included in all tests. Adequate expression was confirmed by sequencing selective samples of positive PCR products. The expression of mRNA for IL-8, IL-10, IL-12, TNF-alpha and TGF-beta1 was detected in all samples at each stage of dioestrus, without any obvious variations indicating a likely modulatory function of these cytokines in differentiation, maintenance or regression of the canine Cl. All tests for the expression of mRNA for IL-4, IL-1beta and IL-2 were negative. More negative than positive results were obtained when testing for the expression of mRNA for IL-6 and IFN-gamma, leading to the conclusion that expression of these two cytokines is at a low level, and no conclusion can be drawn as to their involvement in control of Cl function.

Self-discrepancies and emotional vulnerability: how magnitude, accessibility, and type of discrepancy influence affect.

Two studies examined whether the type of emotional change experienced by individuals is influenced by the magnitude and accessibility of the different types of self-discrepancies they possess. In both studies, subjects filled out a measure of self-discrepancy a few weeks prior to the experimental session. Subjects were asked to list up to 10 attributes each for different self-states--their actual self, their ideal self (their own or others' hopes and goals for them), and their ought self (their own or others' beliefs about their duty and obligations). Magnitude of self-discrepancy was calculated by comparing the attributes in the actual self to the attributes in either the ideal self or the ought self, with the total number of attribute pairs that matched being subtracted from the total number of attribute pairs that mismatched. In Study 1, subjects were asked to imagine either a positive event or a negative event and were then given a mood measure and a writing-speed task. Subjects with a predominant actual:ideal discrepancy felt more dejected (e.g., sad) and wrote more slowly in the negative event condition than in the positive event condition, whereas subjects with a predominant actual:ought discrepancy, if anything, felt more agitated (e.g., afraid) and wrote more quickly in the negative event condition. In Study 2, subjects were selected who were either high in both kinds of discrepancies or low in both. Half of the subjects in each group were asked to discuss their own and their parents' hopes and goals for them (ideal priming), and the other half were asked to discuss their own and their parents' beliefs concerning their duty and obligations (ought priming). For high-discrepancy subjects, but not low-discrepancy subjects, ideal priming increased their dejection whereas ought priming increased their agitation. The implications of these findings for identifying cognitive-motivational factors that may serve as vulnerability markers for emotional problems is discussed.

Parliamentary inquiry into health promoting schools in Victoria: analysis of stakeholder views.

BACKGROUND: In 2009, the Victorian Parliament Legislative Assembly of Australia commissioned a Parliamentary Inquiry into the opportunities for schools to become a focus for promoting healthy community living. Submissions to the Inquiry varied widely in their positions about school health promotion. The aim of this review is to analyze the submissions to identify core themes in the debates about school health promotion and how stakeholders saw schools becoming a focus for promoting healthy communities. METHODS: Submissions (N = 159) were downloaded from the Inquiry website. Open coding was used to code the data. The codes were then refined into conceptual categories to create themes. The Inquiry's terms of reference were used as an organizing framework. RESULTS: Emergent themes included barriers and enablers to school health promotion including the need for stronger leadership from the Departments of Health (DoH) and Education and Early Childhood Development (DEECD). CONCLUSION: Rather than supporting the idea that schools could have a wider role in communities, submissions pointed to the acute need for increased resource allocation to support health promotion in schools, and for coordinated approaches with stronger leadership from the health and education sectors. Without these structures, schools can only address health in an ad hoc manner with limited resources, capacity, and outcomes.

Serum thyroxine concentrations in clinically healthy pet guinea pigs (Cavia porcellus).

BACKGROUND: Guinea pigs (Cavia porcellus) are often presented as patients in veterinary practice. Nevertheless, only limited information is available about endocrine diseases or thyroxine reference values for the species. OBJECTIVE: The aim of this study was to determine serum thyroxine concentrations in a well-defined population of clinically healthy pet guinea pigs. METHODS: Between October 2007 and July 2008, serum samples were collected from 40 clinically healthy guinea pigs of different sexes, ages, and breeds that were presented to our clinic for a general health check or for castration. Pregnant females were excluded from the study. Thyroxine concentration was measured using a chemiluminescence test (Immulite 2000 Canine Total T4). RESULTS: Thyroxine concentrations ranged from 14.2 to 66.9 nmol/L (1.1-5.2 microg/dL) with a median value of 27.0 nmol/L (2.1 microg/dL). Females (n=16) had significantly (P=.039; Mann-Whitney U-test) lower thyroxine values than castrated males (n=8), whereas no differences were found between females and intact males (n=16) or between intact and castrated males. No significant correlation was found between thyroxine concentration and age. CONCLUSION: This is the first report of serum thyroxine reference values for a well-defined population of healthy pet guinea pigs as measured by a chemiluminescence assay. The results were higher than those previously reported for this species and emphasize the importance of using appropriate reference intervals for the diagnosis of hyperthyroidism.

Interferon-gamma sensitizes resistant Ewing's sarcoma cells to tumor necrosis factor apoptosis-inducing ligand-induced apoptosis by up-regulation of caspase-8 without altering chemosensitivity.

Ewing's sarcoma cells are highly susceptible to apoptosis via tumor necrosis factor apoptosis-inducing ligand (TRAIL). Resistance to TRAIL has been linked to deficient expression of caspase-8 in vitro. Here, we report on the status of caspase-8 expression in tumors from patients with Ewing's sarcoma, the effect of interferon-gamma on caspase-8 expression and apoptosis, and the role of caspase-8 for TRAIL- and chemotherapy-mediated apoptosis in Ewing's sarcoma. Using immunohistochemistry, we show that low expression of caspase-8 is seen in about 24% of tumors. Interferon-gamma induces expression of caspase-8 at concentrations achievable in humans and sensitizes cells to TRAIL. Transfection of wild type but not mutant caspase-8 into caspase-8-deficient Ewing's sarcoma cells restored sensitivity to TRAIL, indicating that up-regulation of caspase-8 is sufficient to restore TRAIL sensitivity. In contrast, no role for caspase-8 in chemotherapy-induced apoptosis was identified, because 1) transfection of caspase-8 or treatment with interferon-gamma did not alter the sensitivity of caspase-8-deficient cells to chemotherapeutics, 2) application of chemotherapy did not select for caspase-8-negative tumor cells in vivo, and 3) the caspase-8 status of tumors did not influence survival after chemotherapy-based protocols. In conclusion, our data provide a rationale for the inclusion of interferon-gamma in upcoming clinical trials with TRAIL.