Prevalence of calcium pyrophosphate deposition disease in a cohort of patients diagnosed with seronegative rheumatoid arthritis.

OBJECTIVES: We aimed to characterise the clinical and radiographical phenotype of calcium pyrophosphate dihydrate deposition (CPPD) disease in patients initially diagnosed with seronegative RA, and to increase the awareness that CPPD disease can be falsely diagnosed as seronegative rheumatoid arthritis (RA). METHODS: Altogether 435 early seronegative RA patients were clinically diagnosed in a single rheumatology centre and scheduled for a 10-year follow-up. All clinical data were collected and reviewed. CPPD-related arthritis was suspected if a patient had typical radiographical findings and suitable clinical pattern of CPPD or calcium pyrophosphate crystals were found in the synovial fluid. These patients are the subjects of this study. RESULTS: Among 435 seronegative RA patients, 17 patients (3.9%) (baseline mean age 71.2 years, 82% women) with CPPD disease were identified. CPPD resembling clinical patterns in these patients were: chronic CPP crystal inflammatory arthritis (9 patients), acute CPP crystal arthritis (6 patients) and OA with CPPD (2 patients). All had typical radiographical findings of CPPD: Chondrocalcinosis (CC) of triangular fibrocartilage (17 patients [100%]), CC of knee (9 patients [53%]), CC or narrowing of metacarpophalangeal joints (7 patients [41.2%]), CC of metatarsophalangeal joints (4 patients [23.5%]), CC of symphysis pubis (1 patient [5.8%]), CC of glenohumeral joint (1 patient [5.8%]) and scapholunate advanced collapse (5 patients [29.4%]). None of these patients developed typical RA-like erosions. CONCLUSIONS: CPPD disease can mimic seronegative RA at baseline and is important in the differential diagnosis of seronegative arthritis at baseline and during follow-up. The prevalence of CPPD patients in our early seronegative RA patients was 3.9%, the percentage was 7.0% among patients ≥60 years at baseline.

Does early seronegative arthritis develop into rheumatoid arthritis? A 10-year observational study.

OBJECTIVES: To investigate the 10-year clinical course of patients with seronegative arthritis with the emphasis of reclassification of diagnoses when applicable. METHODS: A total of 1030 patients including 435 seronegative cases were classified as early RA in 1997-2005 at Jyväskylä Rheumatology Centre and prospectively scheduled for a ten-year follow-up. Clinical data from the follow-up visits and the case-reports until and including the 10-year visit or death, whichever happened earlier, were retrospectively collected and reviewed with re-classification of the cases when applicable. Descriptive statistics were used. RESULTS: Among the 435 seronegative cases (69 % women, baseline mean age was 59 years), 13 (13/435 [3%]) could be reclassified as seropositive or erosive RA: 4 turned seropositive (2 for ACPA and 2 for RF [> 2x reference level]) and 9 developed erosions typical for RA. Reclassification revealed 68 (16%) cases of polymyalgia rheumatica, 46 (11%) psoriatic arthritis, 45 (10%) osteoarthritis, 38 (8.7%) spondyloarthritis, 15 (3.4%) plausible reactive arthritis, 10 (2.3%) gout, 17 (3.9%) pseudogout, 6 (1.4%) paraneoplastic arthritis, 6 (1.4%) juvenile arthritis, 2 (0.5%) haemochromatosis, 3 (0.7%) ankylosing spondylitis, 2 (0.5%) giant cell arteritis, and 8 miscellaneous diagnoses. The other 140 patients (32%) could not be reclassified in any clear-cut diagnosis and had features of transient arthritis (n=41), seronegative spondyloarthritis (n=47), while 49 remained unspecified. CONCLUSIONS: Over a 10-year follow-up period, reclassification revealed significant heterogeneity in the diagnosis of seronegative RA. Therefore, seronegative arthritis should not be studied as a homogenous entity.

Survival and safety of infliximab bio-original and infliximab biosimilar (CT-P13) in usual rheumatology care.

OBJECTIVES: Reports to-date indicate similarity between infliximab biosimilar (IB) and infliximab bio-original (IO) in clinical efficacy and safety. This study examines the survival of IB and IO using routinely collected data over a 2-year period. METHODS: Routinely collected clinical data inputted directly in an electronic database at a large rheumatology centre were analysed. Adult patients taking IO or IB for any rheumatological diagnosis were included. Kaplan-Meier survival analyses were used to examine IB and IO survival, with a sub-group analysis among those starting infliximab from 2008 onwards. RESULTS: Out of 395 patients analysed, 53% (n=209) were female; the majority had rheumatoid arthritis (31%) followed by spondyloarthritis (28%). Ninety-nine patients had IB as the first infliximab drug. Patients who started on IB vs. IO as their first infliximab product, had better survival over the first 2 years (log rank=0.001). Discontinuation due to inefficacy was much commoner in IO versus IB users (18 vs. 5%). In patients switching from IO to IB, drug survival was better versus those receiving IB as the first infliximab drug (log rank=0.073). CONCLUSIONS: IB was well-tolerated and comparable to IO, with no additional safety signals identified. The results suggest superior survival of IB over IO over the first 2 years.

Is long-term radiographic joint damage different between men and women? Prospective longitudinal data analysis of four early RA cohorts with greater than 15 years follow-up.

OBJECTIVES: To examine gender-related differences in radiographic joint damage in rheumatoid arthritis (RA) using four prospective early RA cohorts. METHODS: Radiographs of patients from four early prospective RA cohorts were examined. The extent of joint damage in hands and feet was assessed by three evaluators according to the Larsen score (0-100). Descriptive statistics and two-way bootstrap ANOVA with time as a covariate were employed. RESULTS: A total of 312 patients were included who had at least 15 years of follow up: 68 from the Rheumatism Foundation Hospital in Heinola in the 1970s (Heinola1970), 117 patients from Lund University Hospital in the 1980s, (Lund1980), and 81 and 46 patients from Jyväskylä Central Hospital in the 1980s (JYV1980) and the 1990s (JYV1990), respectively. Median Larsen scores in seropositive women vs. men were 43 vs. 48 (p=0.57), 37 vs. 34 (p=0.25), 31 vs. 9.5 (p=0.008), and 3.0 vs. 4.0 (p=0.34) in the Heinola1970, Lund1980, JYV1980, and JYV1990 cohorts, respectively. The corresponding figures in seronegative women vs. men were 12 vs. 23 (p=0.59), 2.0 vs. 8.0 (p=0.36), and 1.0 vs. 1.5 (p=0.63), in the Lund1980, JYV1980 and JYV1990 cohorts. All Heinola patients were seropositive. CONCLUSIONS: After a 15-20 year follow-up period, RA joint damage appears comparable in women and men. The results suggest that management should not differ at least based on gender.

Early Remission Is a Realistic Target in a Majority of Patients with DMARD-naive Rheumatoid Arthritis.

OBJECTIVE: We analyzed remission rates at 3 and 12 months in patients with rheumatoid arthritis (RA) who were naive for disease-modifying antirheumatic drugs (DMARD) and who were treated in a Finnish rheumatology clinic from 2008 to 2011. We compared remission rates and drug treatments between patients with RA and patients with undifferentiated arthritis (UA). METHODS: Data from all DMARD-naive RA and UA patients from the healthcare district were collected using software that includes demographic and clinical characteristics, disease activity, medications, and patient-reported outcomes. Our rheumatology clinic applies the treat-to-target principle, electronic monitoring of patients, and multidisciplinary care. RESULTS: Out of 409 patients, 406 had data for classification by the 2010 RA criteria of the American College of Rheumatology/European League Against Rheumatism. A total of 68% were female, and mean age (SD) was 58 (16) years. Respectively, 56%, 60%, and 68% were positive for anticyclic citrullinated peptide antibodies (anti-CCP), rheumatoid factor (RF), and RF/anti-CCP, and 19% had erosive disease. The median (interquartile range) duration of symptoms was 6 (4-12) months. A total of 310 were classified as RA and 96 as UA. The patients with UA were younger, had better functional status and lower disease activity, and were more often seronegative than the patients with RA. The 28-joint Disease Activity Score (3 variables) remission rates of RA and UA patients at 3 months were 67% and 58% (p = 0.13), and at 12 months, 71% and 79%, respectively (p = 0.16). Sustained remission was observed in 57%/56% of RA/UA patients. Patients with RA used more conventional synthetic DMARD combinations than did patients with UA. None used biological DMARD at 3 months, and only 2.7%/1.1% of the patients (RA/UA) used them at 12 months (p = 0.36). CONCLUSION: Remarkably high remission rates are achievable in real-world DMARD-naive patients with RA or UA.

Clinical effectiveness of CT-P13 (Infliximab biosimilar) used as a switch from Remicade (infliximab) in patients with established rheumatic disease. Report of clinical experience based on prospective observational data.

OBJECTIVE: To gain clinical experience on the effectiveness and safety of switching from infliximab-Remicade(INX) to infliximab-biosimilar-CT-P13(INB) in patients with established rheumatic disease. METHODS: Patients receiving INX treatment at a rheumatology clinic consented to switching from INX to INB. Patient reported outcomes (PROs), disease-activity, and inflammatory markers were recorded at every visit. Generalized estimating equation models and time-dependent area under the curve (AUC) before/during INX and INB treatments were employed. RESULTS: Thirty-nine consecutive patients [mean (SD) age 53 (11), 17 F] with various rheumatic diseases were switched to INB after a mean (SD) of 4.1 (2.3) years on INX. Thirty-one patients were on concomitant methotrexate. At a median (range) of 11 (7.5-13) months following the first administration of INB, AUCs for disease activity and PROs were similar for INX and INB. They were better compared to those prior to INX. Eleven patients (28.2%) discontinued INB, due to INX antidrug antibodies detected prior to INB infusion (n = 3); latent tuberculosis (n = 1); new-onset neurofibromatosis (n = 1); subjective reasons with no objective deterioration of disease (n = 6). CONCLUSION: The clinical effectiveness of INB in both PROs and disease-activity measures was comparable to INX during the first year of switching, with no immediate safety signals. Subjective reasons (negative expectations) may play a role among discontinuations of biosimilars. Larger patient numbers and longer follow-up are necessary for confirming this clinical experience.

Similar clinical outcomes in rheumatoid arthritis with more versus less expensive treatment strategies. Observational data from two rheumatology clinics.

OBJECTIVES: Selection of efficacious medications for rheumatoid arthritis (RA) has tremendously increased over a decade including new costly biologic agents and inexpensive conventional anti-rheumatic drugs, used in combinations for more efficacy. Treatments aim at remission or at least low disease activity. Our objective was to study whether treatment target is reached and to what cost, in patients with RA in two Nordic rheumatology clinics. METHODS: Cross sectional observational clinical data of all patients with RA seen in 2010 in two Nordic county hospital rheumatology units: Kristiansand, Norway and Jyväskylä, Finland, which both serve a population of about 275,000. Measures included patient demographic measures, clinical characteristics, disease activity, functional status, and treatments. Annual costs of medications to the society were calculated per 100 patients, using an assumption that a patient is taking current medications for one year. RESULTS: Patient populations from Kristiansand and Jyväskylä were similar according to age, gender, disease duration, and prevalence of RF and CCP. Disease activity was low and patients' functional status well reserved in both clinics. Almost twice as many patients in Kristiansand than in Jyväskylä (33% vs. 17%) used biologic agents. A combination of conventional anti-rheumatic drugs was currently used by <1% of patients in Kristiansand and by 37% of patients in Jyväskylä. Estimated annual costs of medications per 100 patients were €508,000 in Kristiansand and €280,000 in Jyväskylä. CONCLUSIONS: Treatment target of remission/low disease activity and good functional status can be reached in RA using expensive and less-expensive anti-rheumatic drugs.

Application of change-point analysis to determine winter sleep patterns of the raccoon dog (Nyctereutes procyonoides) from body temperature recordings and a multi-faceted dietary and behavioral study of wintering.

BACKGROUND: A multi-faceted approach was used to investigate the wintertime ecophysiology and behavioral patterns of the raccoon dog, Nyctereutes procyonoides, a suitable model for winter sleep studies. By utilizing GPS tracking, activity sensors, body temperature (Tb) recordings, change-point analysis (CPA), home range, habitat and dietary analyses, as well as fatty acid signatures (FAS), the impact of the species on wintertime food webs was assessed. The timing of passive bouts was determined with multiple methods and compared to Tb data analyzed by CPA. RESULTS: Raccoon dogs displayed wintertime mobility, and the home range sizes determined by GPS were similar or larger than previous estimates by radio tracking. The preferred habitats were gardens, shores, deciduous forests, and sparsely forested areas. Fields had close to neutral preference; roads and railroads were utilized as travel routes. Raccoon dogs participated actively in the food web and gained benefit from human activity. Mammals, plants, birds, and discarded fish comprised the most important dietary classes, and the consumption of fish could be detected in FAS. Ambient temperature was an important external factor influencing Tb and activity. The timing of passive periods approximated by behavioral data and by CPA shared 91% similarity. CONCLUSIONS: Passive periods can be determined with CPA from Tb recordings without the previously used time-consuming and expensive methods. It would be possible to recruit more animals by using the simple methods of data loggers and ear tags. Hunting could be used as a tool to return the ear-tagged individuals allowing the economical extension of follow-up studies. The Tb and CPA methods could be applied to other northern carnivores.

Body mass dependence of glycogen stores in the anoxia-tolerant crucian carp (Carassius carassius L.).

Glycogen is a vital energy substrate for anaerobic organisms, and the size of glycogen stores can be a limiting factor for anoxia tolerance of animals. To this end, glycogen stores in 12 different tissues of the crucian carp (Carassius carassius L.), an anoxia-tolerant fish species, were examined. Glycogen content of different tissues was 2-10 times higher in winter (0.68-18.20% of tissue wet weight) than in summer (0.12-4.23%). In scale, bone and brain glycogen stores were strongly dependent on body mass (range between 0.6 and 785 g), small fish having significantly more glycogen than large fish (p < 0.05). In fin and skin, size dependence was evident in winter, but not in summer, while in other tissues (ventricle, atrium, intestine, liver, muscle, and spleen), no size dependence was found. The liver was much bigger in small than large fish (p < 0.001), and there was a prominent enlargement of the liver in winter irrespective of fish size. As a consequence, the whole body glycogen reserves, measured as a sum of glycogen from different tissues, varied from 6.1% of the body mass in the 1-g fish to 2.0% in the 800-g fish. Since anaerobic metabolic rate scales down with body size, the whole body glycogen reserves could provide energy for approximately 79 and 88 days of anoxia in small and large fish, respectively. There was, however, a drastic difference in tissue distribution of glycogen between large and small fish: in the small fish, the liver was the major glycogen store (68% of the stores), while in the large fish, the white myotomal muscle was the principal deposit of glycogen (57%). Since muscle glycogen is considered to be unavailable for blood glucose regulation, its usefulness in anoxia tolerance of the large crucian carp might be limited, although not excluded. Therefore, mobilization of muscle glycogen under anoxia needs to be rigorously tested.

Selective fatty acid mobilization from adipose tissues of the pheasant (Phasianus colchicus mongolicus) during food deprivation.

Avian response to fasting has been examined intensively in penguins (Aptenodytes spp.) adapted to long-term food deprivation but less in species experiencing shorter fasts. Thus, the selectivity in (i) incorporating different fatty acids (FA) from diet into total lipids of white adipose tissue (WAT) and liver and (ii) mobilizing FA from these tissues was examined in pheasants Phasianus colchicus mongolicus fed or fasted for 4 d. Dietary FA were selectively incorporated into intra-abdominal and subcutaneous WAT having a similar composition. The WAT lipids contained higher proportions of saturated and monounsaturated FA and less polyunsaturated FA (PUFA) than the dietary profile. However, the isomers of 20:1 and 22:1 were incorporated inefficiently into the WAT lipids. The essential C18 PUFA precursors having smaller percentages in the pheasant tissues than in the diet were likely converted into longer-chain derivatives probably utilized to a great extent for structural lipids of muscles and organs. During food deprivation, the pheasants preferentially utilized 16:1n-7, 18:3n-3, 18:1n-9, and 16:0 but preserved long-chain saturated and unsaturated FA. Mobilization was more efficient for shorter-chain FA and increased with Delta9-desaturation. The hepatic FA profile was resistant to the 4-d period of food deprivation. The results demonstrate that the incorporation of FA into WAT and their mobilization from lipid stores are selective not only in mammals but also in birds.

Response to fasting in an unnaturally obese carnivore, the captive European polecat Mustela putorius.

The European polecat (Mustela putorius) is a naturally lean carnivore prone to excessive weight gain in captivity. This study assessed its suitability to investigate the natural history of the obese phenotype displayed in overweight humans, domestic animals, and seasonally obese wild mammals. Ten farm-bred polecats were subjected to a 5-day fast with 10 controls. Obesity (40% body fat) was associated with an unfavorable plasma lipid profile and high glucose and insulin concentrations. The polecats were in phase II of fasting with normoglycemia, low liver carbohydrate stores, and decreased plasma concentrations of urea and most amino acids. Although the plasma nonesterified fatty acid (NEFA) levels were elevated, the adipose tissue lipase activities suggested a blunted lipolytic response. Lipid mobilization was more efficient from intraabdominal fat. The animals developed hepatic lipidosis with elevated NEFA influx into the liver and losses of n-3 polyunsaturated fatty acids and arginine as hypothetical etiological factors. The plasma leptin, insulin, and triiodothyronine levels decreased but were not accompanied by reduced sex steroid or increased stress hormone concentrations. The blunted lipolytic response often encountered in obesity suggests that the organism is trying to defend the obese phenotype. Liver lipidosis and decreased insulin and triiodothyronine levels seem to be among the most consistent responses to fasting manifested in diverse mammalian orders and different levels of body fatness. The polecat could be recommended as an easily accessible carnivorean model to study the natural history of the obese phenotype and its comorbidities.

Fatty acid composition and development of hepatic lipidosis during food deprivation--mustelids as a potential animal model for liver steatosis.

Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome characterized by asymptomatic hepatic steatosis. It is present in most cases of human obesity but also caused e.g., by rapid weight loss. The patients have decreased n-3 polyunsaturated fatty acid (PUFA) proportions with decreased percentages of 18:3(n-3), 20:5(n-3) and 22:6(n-3) and an increased n-6/n-3 PUFA ratio in liver and/or white adipose tissue (WAT). The present study examined a new experimental model to study liver steatosis with possible future applications to NAFLD. Ten European polecats (Mustela putorius), the wild form of the domestic ferret, were food-deprived for 5 days with 10 fed animals as controls. The food-deprived animals showed micro- and macrovesicular hepatic steatosis, decreased proportions of 20:5(n-3), 22:6(n-3) and total n-3 PUFA and increased n-6/n-3 PUFA ratios in liver and WAT. At the same time, the product/precursor ratios decreased in liver. The observed effects can be due to selective fatty acid mobilization preferring n-3 PUFA over n-6 PUFA, decreased Delta5 and Delta6 desaturase activities, oxidative stress, decreased arginine availability and activation of the endocannabinoid system. Hepatic lipidosis induced by food deprivation was manifested in the fatty acid composition of the polecat with similarities to human NAFLD despite the different principal etiologies.

Seasonal rhythms of body temperature in the free-ranging raccoon dog (Nyctereutes procyonoides) with special emphasis on winter sleep.

The raccoon dog (Nyctereutes procyonoides) is the only canid with passive overwintering in areas with cold winters, but the depth and rhythmicity of wintertime hypothermia in the wild raccoon dog are unknown. To study the seasonal rhythms of body temperature (T(b)), seven free-ranging animals were captured and implanted with intra-abdominal T(b) loggers and radio-tracked during years 2004-2006. The average size of the home ranges was 306+/-26 ha, and the average 24 h T(b) was 38.0+/-<0.01 degrees C during the snow-free period (May-November). The highest and lowest T(b) were usually recorded around midnight (21:00-02:00 h) and between 05:00-11:00 h, respectively, and the range of the 24 h oscillations was 1.2+/-0.01 degrees C. The animals lost approximately 43+/-6% of body mass in winter (December-April), when the average size of the home ranges was 372+/-108 ha. During the 2-9-wk periods of passivity in January-March, the average 24 h T(b) decreased by 1.4-2.1 degrees C compared to the snow-free period. The raccoon dogs were hypothermic for 5 h in the morning (06:00-11:00 h), whereas the highest T(b) values were recorded between 16:00-23:00 h. The range of the 24 h oscillations increased by approximately 0.6 degrees C, and the rhythmicity was more pronounced than in the snow-free period. The ambient temperature and depth of snow cover were important determinants of the seasonal T(b) rhythms. The overwintering strategy of the raccoon dog resembled the patterns of winter sleep in bears and badgers, but the wintertime passivity of the species was more intermittent and the decrease in the T(b) less pronounced.

Selective seasonal fatty acid accumulation and mobilization in the wild raccoon dog (Nyctereutes procyonoides).

Previous studies on laboratory rodents, rabbits and humans have demonstrated that fatty acid (FA) mobilization from white adipose tissue (WAT) is selective and its efficiency is related to FA structure. Selective FA mobilization was also documented in a carnivore, the farmed raccoon dog (Nyctereutes procyonoides), fasted for 8 weeks. The present study explored whether similar selectivity of FA mobilization was manifested in wild mammals experiencing seasonal food scarcity and abundance. Fractional mobilization from and incorporation into WAT of a wide spectrum of FA were studied by gas-liquid chromatography from the subcutaneous WAT of free-ranging raccoon dogs with the same individuals sampled in consecutive seasons. The wintertime FA mobilization was selective and mostly confirmed the patterns of FA release in captivity. Mobilization correlated inversely with the FA chain length but increased with unsaturation and when the first double bond was located closer to the methyl end. 18-20 C n-3 polyunsaturated FA (PUFA) and 14-17 C monounsaturated FA (MUFA) were preferentially mobilized while 19-24 C saturated FA and MUFA were preserved during wintering. The summertime FA incorporation correlated inversely with the chain length and increased with unsaturation and in MUFA and PUFA with double bonds closer to the methyl end. The principles of selective FA mobilization were valid in wild mammals. FA incorporation was also selective and reversed the wintertime losses of the preferably mobilized FA.

Physiological adaptations to fasting in an actively wintering canid, the Arctic blue fox (Alopex lagopus).

This study investigated the physiological adaptations to fasting using the farmed blue fox (Alopex lagopus) as a model for the endangered wild arctic fox. Sixteen blue foxes were fed throughout the winter and 32 blue foxes were fasted for 22 d in Nov-Dec 2002. Half of the fasted blue foxes were food-deprived again for 22 d in Jan-Feb 2003. The farmed blue fox lost weight at a slower rate (0.97-1.02% body mass d(-1)) than observed previously in the arctic fox, possibly due to its higher initial body fat content. The animals experienced occasional fasting-induced hypoglycaemia, but their locomotor activity was not affected. The plasma triacylglycerol and glycerol concentrations were elevated during phase II of fasting indicating stimulated lipolysis, probably induced by the high growth hormone concentrations. The total cholesterol, HDL- and LDL-cholesterol, urea, uric acid and total protein levels and the urea:creatinine ratio decreased during fasting. Although the plasma levels of some essential amino acids increased, the blue foxes did not enter phase III of starvation characterized by stimulated proteolysis during either of the 22-d fasting procedures. Instead of excessive protein catabolism, it is liver dysfunction, indicated by the increased plasma bilirubin levels and alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase activities, that may limit the duration of fasting in the species.

Adaptations of the raccoon dog (Nyctereutes procyonoides) to wintering--effects of restricted feeding or periodic fasting on lipids, sex steroids and reproduction.

The raccoon dog (Nyctereutes procyonoides) is an omnivorous canid with autumnal hyperphagia and fattening followed by mid-winter passivity and fasting in boreal latitudes with seasonal snow cover. The effects of two different feeding levels (400 or 200 kcal/animal/d) or fasting (5-week fasting+1-week feeding+3-week fasting) on plasma lipids, sex steroids and reproductive success of farm-bred raccoon dogs (n=60 females and 24 males) were studied in winter. The body masses, body mass indices (BMIs) and levels of plasma triacylglycerols (TG), total cholesterol and low- and high-density lipoprotein cholesterol did not differ between the fed and the restrictively fed animals. During fasting, the plasma TG concentrations increased and the BMIs decreased, indicating the release of fatty acids from adipose tissue. After the fasting periods, the levels of plasma cholesterol and high-density lipoprotein cholesterol increased, whereas the TG levels decreased indicating the rebuilding of energy reserves. The fact that the different wintertime feeding regimes had no impact on the plasma glucose, total protein, cortisol, estradiol, progesterone or testosterone levels, or on the reproductive success, indicates versatile adaptive capacity in the species.

Thermoregulatory adaptations of the overwintering captive raccoon dog (Nyctereutes procyonoides) in boreal climate.

The raccoon dog (Nyctereutes procyonoides) is a nocturnal canid thought to utilise passive wintering strategy in the boreal climate. To record the deep body temperature (T(b)), 12 farmed raccoon dogs were implanted with intra-abdominal T(b) loggers on November 26, 2003. Between December 3, 2003 and January 27, 2004 half of the animals were fasted for 8 weeks. The amplitude of the diurnal T(b) oscillations increased due to fasting. However, the mean diurnal T(b) was lower in the fasted animals only during two occasions. Unlike observed previously in other species, not only did the raccoon dogs experience hypothermia between 0600 and 1000 hr but also hyperthermia between noon and 1800 hr. The fasted animals were as active as the fed animals measured after 42-43 days of fasting and there was a significant cross-correlation between physical activity and T(b). The nocturnal period of hypothermia is probably an adaptation to save energy during food deprivation. The diurnal hyperthermia could be explained by the opportunistic foraging behaviour of the species. Opposite to the established assumptions, the raccoon dog does not seem to enter winter sleep on fur farms. In the future it is important to determine if true winter sleep occurs in nature in the species.

Adaptations to fasting in the American mink (Mustela vison): carbohydrate and lipid metabolism.

The aim of this study was to investigate whether the actively wintering American mink Mustela vison is strictly dependent on continuous food availability or if it has evolved physiological adaptations to tolerate nutritional scarcity. Fifty farm-bred male minks were divided into a fed control group and four experimental groups fasted for 2, 3, 5 or 7 days. The rate of weight loss was several-fold higher (1.5-3.2% day(-1)) in the mink than recorded previously in larger carnivores utilizing passive wintering strategies. The minks remained normoglycaemic, although their liver glycogen stores and glucose-6-phosphatase activities decreased during fasting. Adipose tissue constituted approximately 36% of their body mass after 7 days of food deprivation. Intra-abdominal fat, especially retroperitoneal but also mesenteric adipose tissue, were the most important fat depots to be hydrolyzed, but the ability of the mink to utilize its body lipids during fasting may be limited. The increased liver size, hepatic triacylglycerol accumulation and increases in the activities of plasma aminotransferases indicated liver dysfunction. Food deprivation also affected the red blood cell indices, and the blood monocyte and lymphocyte counts decreased suggesting immunosuppression during fasting. The results of the present study suggest that the mink has not evolved sophisticated adaptations to wintertime fasting.

Phytoestrogens alter the reproductive organ development in the mink (Mustela vison).

The aim of the present study was to examine the reproductive effects of two perorally applied phytoestrogens, genistein (8 mg/kg/day) and beta-sitosterol (50 mg/kg/day), on the mink (Mustela vison) at human dietary exposure levels. Parental generations were exposed over 9 months to these phytoestrogens and their offspring were exposed via gestation and lactation. Parents and their offspring were sampled 21 days after the birth of the kits. Sex hormone levels, sperm quality, organ weights, and development of the kits were examined. The exposed females were heavier than the control females at the 1st postnatal day (PND). The control kits were heavier than the exposed kits from the 1st to the 21st PND. Phytoestrogens did not affect the organ weights of the adult minks, but the relative testicular weight of the exposed kits was higher than in the control kits. The relative prostate weight was higher and the relative uterine weight lower in the beta-sitosterol-exposed kits than in the control kits. Moreover, the plasma dihydrotestosterone levels were lower in the genistein-exposed male kits compared to the control male kits. This study could not explain the mechanisms behind these alterations. The results indicate that perinatal phytoestrogen exposures cause alterations in the weight of the reproductive organs of the mink kits.

Circannual leptin and ghrelin levels of the blue fox (Alopex lagopus) in reference to seasonal rhythms of body mass, adiposity, and food intake.

The aim of the study was to investigate the circannual rhythms of leptin and ghrelin in the blue fox, a variant of the endangered arctic fox, in relation to its seasonal cycles of body mass, adiposity and food intake. The effects of long-term fasting and exogenous melatonin treatment on these weight-regulatory hormones were also investigated. The leptin concentrations of the blue fox increased during the autumnal accumulation of fat and decreased during the wintertime and vernal weight loss periods. The leptin levels peaked 2-6 weeks before the maximum values were observed for the body mass indices, voluntary food intake, and body masses. The ghrelin concentrations fluctuated widely during the autumn but decreased in the winter in association with suppression of food intake. Exogenous melatonin advanced the seasonal changes in the food intake of the blue fox but did not affect the seasonal rhythms of leptin and ghrelin concentrations. The leptin concentrations did not respond to the 3-week fasting periods in a consistent way, but the ghrelin levels increased due to food deprivation. In addition to the amount of fat in the body the leptin secretion of the blue fox may be regulated also by other factors. The blue fox may also express seasonal changes in its leptin sensitivity. Our results reinforce the hypothesis that leptin does not function as an acute indicator of body adiposity in seasonal carnivores but rather as a long-term signal of nutritional status.