Showing papers on "Mink published in 1985"

Toxicological manifestations of 2,4,5,‐2’,4’,5'‐, 2,3,6,2’,3’,6'‐, and 3,4,5,3’,4’,5'‐hexachlorobiphenyl and Aroclor 1254 in mink

Abstract: Adult female mink were fed diets that contained 2.5 ppm Aroclor 1254, 0.1 or 0.5 ppm 3,4,5,3’,4’,5'‐hexachlorobiphenyl (345 HCB), 2.5 or 5.0 ppm 2,4,5,2’,4’,5'‐hexa‐chlorobiphenyl (245 HCB) or 2,3,6,2’,3’,6'‐hexachlorobiphenyl (236 HCB), or a control diet from 1 mo prior to breeding through parturition. All mink fed 0.5 ppm 345 HCB died within 60 d, while those fed 0.1 ppm showed 50% mortality after 3 mo exposure. Only one stillborn kit was whelped in the Aroclor 1254 group. No adverse reproductive effects were observed in the animals fed 236 HCB or 245 HCB. Plasma progesterone concentrations were significantly depressed by Aroclor 1254 and significantly elevated by 0.1 ppm 345 HCB. 170‐Estradiol concentrations were not significantly altered by any of the dietary treatments. Hepatic microsomal cytochrome P‐450 concentrations were significantly elevated by all treatments except 236 HCB, with the largest increases occurring in mink exposed to Aroclor 1254 and 345 HCB. Aminopyrine N‐demethylase activity was ...

An avian influenza A virus killing a mammalian species--the mink. Brief report.

Abstract: During October of 1984 an influenza epidemic occurred on mink farms in the coastal region of South Sweden. Six strains of an influenza A virus were isolated. All six isolates were of the H10 subtype in combination with N4. The H10 subtype in combination with various N subtypes was hitherto only known to occur in avian strains, the prototype being the A/chicken/Germany/N/49 (H10N7) virus.

Sex-related differences in the diet of the mink Mustela vison

Abstract: The diets of free-ranging male and female mink were sampled by analysing faeces collected from radio-tagged individuals. Significant sex differences were apparent in the predation upon three of the five principal prey groups. The larger males preyed much more heavily upon lagomorphs, the largest prey taken, while females preyed more upon fish and crustaceans than did males. These differences were consistent in each season except the autumn (September to November), when males preyed more heavily upon fish and crustacea than did females. Due to their large size, adult lagomorphs are felt to be relatively unavailable to female mink. Male mink are apparently large enough to specialize on lagomorphs, and male mink niche breadth was consistently lower than that of females. Dietary overlap approximated to 40% in all seasons except summer (68%), when female predation upon lagomorphs reached a peak. This reduction in intraspecific feeding competition was felt to be a valuable side-effect of body-size dimorphism.

Susceptibility of wild mouse cells to exogenous infection with xenotropic leukemia viruses: control by a single dominant locus on chromosome 1.

Abstract: Although xenotropic murine leukemia viruses cannot productively infect cells of laboratory mice, cells from various wild-derived mice can support replication of these viruses. Although the virus-sensitive wild mice generally lack all or most of the xenotropic proviral genes characteristic of inbred strains, susceptibility to exogenous infection is unrelated to inheritance of these sequences. Instead, susceptibility is controlled by a single dominant gene, designated Sxv, which maps to chromosome 1. Sxv is closely linked to, but distinct from Bxv-1, the major locus for induction of xenotropic murine leukemia viruses in laboratory mice. Genetic experiments designed to characterize Sxv show that this gene also controls sensitivity to a wild mouse virus with the interference properties of mink cell focus-forming murine leukemia viruses, and that Sxv-mediated susceptibility to xenotropic murine leukemia viruses is restricted by the mink cell focus-forming virus resistance gene Rmcf. These data, together with genetic mapping of the mink cell focus-forming virus cell surface receptor locus to this same region of chromosome 1, suggest that Sxv may encode a wild mouse variant of the mink cell focus-forming virus receptor that allows penetration by xenotropic murine leukemia viruses.

Friend and Moloney murine leukemia viruses specifically recombine with different endogenous retroviral sequences to generate mink cell focus-forming viruses.

Abstract: A group of mink cell focus-forming (MCF) viruses was derived by inoculation of NFS/N mice with Moloney murine leukemia virus (Mo-MuLV 1387) and was compared to a similarly derived group of MCF viruses from mice inoculated with Friend MuLV (Fr-MuLV 57). Antigenic analyses using monoclonal antibodies specific for MCF virus and xenotropic MuLV envelope proteins and genomic structural analyses by RNase T1-resistant oligonucleotide finger-printing indicated that the Moloney and Friend MCF viruses arose by recombination of the respective ecotropic MuLVs with different endogenous retrovirus sequences of NFS mice.

The effects of photoperiod and melatonin on serum prolactin levels of mink during the autumn molt.

Abstract: An experiment was conducted to determine the effects of a reduced daily photoperiod and exogenous melatonin on serum prolactin levels of mink during the autumn molt and growth of the winter pelage. During the last week of June, adult standard dark female mink (Mustela vision) were exposed to natural changes in daylength (controls), a reduced photoperiod of 6 h light: 18 h dark (6L:18D) or exposure to natural changes in daylength and treated with melatonin (10 mg) in a Silastic implant inserted subcutaneously over the scapular area. Beginning July 2, and continuing through October 22, blood samples were collected at nine biweekly intervals, and serum prolactin concentrations were quantified by a heterologous double antibody radioimmunoassay. Both reduced photoperiod and exogenous melatonin caused serum prolactin levels to decline rapidly after mid-July, resulting in concentrations that were significantly lower than those of controls 6 to 8 wk earlier. These data suggest that growth of the winter pelage of mink is strongly associated with declining prolactin levels. It appears that part of the photoperiodic-induced effects on fur growth of the mink are mediated through melatonin and its effects on prolactin synthesis and/or secretion.

Analysis of Aleutian disease virus infection in vitro and in vivo: demonstration of Aleutian disease virus DNA in tissues of infected mink.

Abstract: Aleutian disease virus (ADV) infection was analyzed in vivo and in vitro to compare virus replication in cell culture and in mink. Initial experiments compared cultures of Crandell feline kidney (CRFK) cells infected with the avirulent ADV-G strain or the highly virulent Utah I ADV. The number of ADV-infected cells was estimated by calculating the percentage of cells displaying ADV antigen by immunofluorescence (IFA), and several parameters of infection were determined. Infected cells contained large quantities of viral DNA (more than 10(5) genomes per infected cell) as estimated by dot-blot DNA-DNA hybridization, and much of the viral DNA, when analyzed by Southern blot hybridization, was found to be of a 4.8-kilobase-pair duplex monomeric replicative form (DM DNA). Furthermore, the cultures contained 7 to 67 fluorescence-forming units (FFU) per infected cell, and the ADV genome per FFU ratio ranged between 2 X 10(3) and 164 X 10(3). Finally, the pattern of viral antigen detected by IFA was characteristically nuclear, although cytoplasmic fluorescence was often found in the same cells. Because no difference was noted between the two virus strains when cultures containing similar numbers of infected cells were compared, it seemed that both viruses behaved similarly in infected cell culture. These data were used as a basis for the analysis of infection of mink by virulent Utah I ADV. Ten days after infection, the highest levels of viral DNA were detected in spleen (373 genomes per cell), mesenteric lymph node (MLN; 750 genomes per cell), and liver (373 genomes per cell). In marked contrast to infected CRFK cells, the predominant species of ADV DNA in all tissues was single-stranded virion DNA; however, 4.8-kilobase-pair DM DNA was found in MLN and spleen. This observation suggested that MLN and spleen were sites of virus replication, but that the DNA found in liver reflected sequestration of virus produced elsewhere. A final set of experiments examined MLN taken from nine mink 10 days after Utah I ADV infection. All of the nodes contained ADV DNA (46 to 750 genomes per cell), and although single-stranded virion DNA was always the most abundant species, DM DNA was observed. All of the lymph nodes contained virus infectious for CRFK cells, but when the genome per FFU ratio was calculated, virus from the lymph nodes required almost 1,000 times more genomes to produce an FFU than did virus prepared from infected cell cultures.(ABSTRACT TRUNCATED AT 400 WORDS)

Role of the pineal gland in the photoperiodic control of reproductive and non-reproductive functions in mink (Mustela vison).

Abstract: Mink are long-lived mammals that exhibit seasonal changes in body weight, gonadal activity, pelage and plasma prolactin levels. Mating in February-March is followed by an obligatory delay in implantation during which the corpora lutea stay quiescent. All these events are controlled by annual variations in daylength. The role of the pineal gland and its product, melatonin, in conveying photic information to the target organs has been studied. Pineal denervation by bilateral ablation of the cervical superior ganglia rendered the mink unresponsive to artificial manipulations of the daily photoperiod: prolactin and progesterone secretion and the spring moult were no longer stimulated by long days or inhibited by short days in pregnant females; in the same way the increase in body weight in late summer and the autumn moult were no longer advanced by artificial shortening of the photoperiod. Pinealectomy seemed to desynchronize body weight, prolactin and moulting cycles from those in intact mink. Melatonin injections reproduced the effects of short days on hormonal secretion during the delayed implantation period. Melatonin capsules given to males during the phase of testicular activity delayed the decrease in body weight, testicular regression and onset of the spring moult exactly as did short days. In contrast, melatonin administered during the phase of testicular inactivity triggered an increase in body weight, the onset of the spring moult and testicular recrudescence in this short-day breeder. These results support the hypothesis that in mink all photoperiodic signals are conveyed by the pineal gland. But although the pineal seems essential for the seasonal timing of the cycles, it does not modify the events themselves once they are initiated.

Multivariate variation in feral American mink (Mustela vison) from Southern Norway

Abstract: Multiple group principal component analysis was used to investigate the morphological relationships between feral American mink from three areas of Southern Norway based on 15 skull dimensions. The first principal axis calculated from the variance-covariance matrix of log-transformed data is usually interpreted as a growth axis. In the present analysis, the scores of the first principal axis of males were found to be uncorrelated with estimated age for specimens younger than seven months old, and was interpreted as a growth-free size axis. However, the second component of males was found to reflect mainly growth in the postorbital area. The first component of females was thought to reflect a mixing of growth-out and growth-in size variation. One of the reasons for separating size and size-free variation in the present work was to test whether growth-dependent size influenced the assessment of geographic variation within each sex. The scores on the components reflecting size variation (growthout and growth-in) were, however, not found to deviate significantly between the areas. Discriminant analyses run on the component scores, both with size variation included and excluded, gave the same result. In mean, the mink from Western Norway deviated significantly from the mink from Trondelag and Eastern Norway, while the mink from the two latter areas did not deviate morphometrically. The deviation found was in shape rather than in size of both sexes.

Temporal replication of the Pullman strain of Aleutian disease virus in royal pastel mink.

Abstract: Information was sought on the temporal replication of Aleutian disease virus in 27 royal pastel mink. Groups of three were examined 8 to 126 days after they were inoculated subcutaneously with 10(3) 50% lethal doses of the Pullman strain. Much individual variation was noted in the onset of infection, occurrence of viremia, and extent of virus replication in the tissues. Thus, virus was detected in lymph nodes regional to the site of inoculation in only some mink during the first 14 days after inoculation. During this period, virus was often present as well in the mesenteric lymph node and spleen. First detected on day 10, viremia was present in all mink examined on day 28 but occurred irregularly thereafter, even when virus was widespread in the tissues. Except in five mink succumbing to the disease, the tissue distribution of virus after day 28 tended to be more limited, and the titers were generally lower than they had been earlier. Even though present in the lymph nodes and spleen, virus was often absent from the kidney, liver, and intestine after day 28. Specific antibody was detected on day 28 and was present in all mink thereafter, ostensibly without any adverse effect on virus replication. In most mink, the infection was considered subclinical, for it was usually not accompanied by a rise in serum gamma globulin or by morphologic evidence of the disease. The virologic findings in this study have a bearing on the relationship of subclinical infections to both horizontal and vertical transmission of the virus.

Toxoplasmosis in marsupials in a zoological collection.

Abstract: (or domestic cat) foods, combined with the attitude that multivitamin/mineral additives "balance" the diet, poses a constant concern about the welfare of mustelids in captivity. Mink diets have been well established by mink ranchers, sea otter diets receive attention in aquaria, and recently, domestic ferret diets have reappeared on the market. None of them are at all similar to dog food diets, especially in the protein sources.2 Captive badgers might well do better on diets closer to mink, than to domestic dogs. Mustelids in captivity, however, tend to resist dietary changes. Hair loss is not a typical response to diet change, and is, indeed, more typical of prolonged nutritional imbalance.3

Trichinella spiralis in wild animals, cats, mice, rats and farmed fur animals in Finland.

Abstract: A total of 1 399 samples of wild animals, cats, mice, rats and fur animals were examined for Trichinella larvae during the period 1.1.1982-30.6.1984. Samples were obtained both from the problem area, were Trichinella larvae had been found in pigs, and for comparison from the rest of Finland. The frequency of the infection in wild carnivores, badgers, pine martens, raccoon dogs, foxes and wild mink was significantly higher in the problem area than in the rest of Finland.

Carcinoma of the Anal Sac Glands in Ranch Mink

Abstract: During a 14-year period, carcinoma of the anal sac apocrine glands was found in 52 pastel and 8 sapphire mink (Mustela vison) kept for studies on slow viral diseases. The pastel mink varied in age from 72 to 135 months (mean age 108 months), the sapphire mink from 63 to 100 months (mean age 81 months). All but one pastel mink were females. The primary tumor varied in size from masses that caused bulges in the perineum to those that were found only after microscopic examination of the anal sac glands. Although the primary tumor grew mainly by expansion with little local infiltration, 41 of the 60 tumors had metastasized to the regional lymph nodes and sometimes also to more distant sites. The striking propensity of the carcinoma to metastasize while still small, even microscopic, often resulted in massive secondary growths, notably in the iliac lymph nodes. Hypercalcemia did not accompany the carcinoma. Its varied microscopic appearance included solid, glandular, squamous cell, and spindle or round cell components. Combinations of them formed mixed or complex histologic patterns, no doubt largely attributable to neoplastic proliferation of myoepithelial cells and squamous metaplasia of the apocrine gland epithelium. Although its cause remains obscure, the carcinoma appeared to arise from small foci of hyperplastic apocrine glands, sometimes in relation to both anal sacs. The tumor is a common and distinctive expression of neoplasia in older ranch mink.

Endogenous Type-C Viral Expression during Lymphoma Development in Irradiated NFS Mice

Abstract: The expression of the type-C retrovirus and the virus-related components in NFS mice were examined during preleukemic and leukemic phases after fractionated whole-body X irradiation. The NFS mice were highly susceptible to induction of thymoma by fractionated X irradiation. The leukemic tissues were negative for infectious type-C virus, as detected by both the XC-plaque test and mink S+ L- focus-inducing assays, but contained a substantially higher level of viral-specific RNA-dependent DNA polymerase activity and a major core protein p30 than the corresponding tissues from unirradiated age-control mice. In the preleukemic phase, the amount of p30-related antigen increased transiently in spleen. The leukemic cell lines established from radiation-induced lymphomas produced particulate entities with a buoyant density of about 1.15 g/ml. These virus-like particles lacked in vitro infectivity to mouse cells and mink lung cells and leukemogenicity in syngeneic mice. The p30-related antigens of these particles were immunologically similar to that of xenotropic virus derived from NZB mouse.

Regional assignment of the genes for TK1, GALK, ALDC, and ESD on chromosome 8 in the American mink by chromosome-mediated gene transfer

Abstract: A panel of clones of mink-Chinese hamster somatic cell hybrids was analysed to obtain data for assigning the genes for thymidine kinase-1 (TK1), galactokinase (GALK), subunit C of aldolase (ALDC), and esterase D (ESD) to specific mink chromosomes. The results demonstrate that the genes for TK1, GALK, ALDC and ESD are syntenic and located on mink chromosome 8. Prometaphase analysis of transformed mouse cells obtained by transfer of mink genes by means of metaphase chromosomes demonstrated the presence of mink chromosome 8 fragments of different sizes in some of the independent transformants. Segregation analysis of these fragments and mink TK1, GALK, ALDC and ESD allowed us to assign the genes for TK1 and GALK to 8p24, ALDC to pter-8p25, and ESD to 8q24-8qter.

Heterologous radioimmunoassay of LH in two seasonally breeding animals: hare (Lepus europaeus) and mink (Mustela vison)

Abstract: A heterologous radioimmunoassay using ovine LH as the labelled hormone, canine LH as the standard, and a rabbit antiovine LH serum (GDN 15) was developed and validated for LH measurement in the pla

Mink and muskrat interaction:a structural analysis

Abstract: . There is no unique way of representing a linear vector process, but in practice these processes are often characterized by their ARIMA representations. It is argued that for the purpose of interpretation the choice of canonical form is important, and the chosen form should as closely as possible correspond to existing prior information about the process, if any. This point is demonstrated by reanalysing the well-known mink and muskrat data of Hudson's Bay Company from the year 1848 till 1909 using two separate single-equation transfer function noise models to describe the relationship from mink to muskrat and the feedback link from muskrat to mink. The results thus obtained are from the practical point of view more informative than the corresponding ARIMA models.

Histamine and secondary autoimmune infertility in dark mink (Mustela vison).

Abstract: Testicular histamine content was higher in December (the time of sexual quiescence) that in March (breeding time) in opaline mink. Although testicular histamine synthesis increased in March over December, the increased cellular mass and increased histaminase activity prevented the biogenic amine from rising. Dark mink, however, had higher gonadal levels of histamine in March than in December owing to an increased rate of synthesis and a decreased rate of inactivation that correlated well with the onset of autoimmune infertility in this strain. Pastel mink were intermediate to the opalines, and dark mink indicative of strain differences in the genetic control of gonadal histamine synthesis and inactivation.

Regional assignments of eight genes on chromosome 2 in the American mink

Abstract: Chromosomal rearrangements involving mink chromosome 2 in mink-Chinese hamster and mink-mouse hepatoma somatic hybrids were identified. By means of these rearrangements, we assigned the genes for HK1,