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D L Swanson

Publications and source records attributed to D L Swanson.

16 recordsLinked to original sources
PubMed2001

Are summit metabolism and thermogenic endurance correlated in winter-acclimatized passerine birds?

Small birds exhibiting marked winter improvement of cold tolerance also show elevated summit metabolic rates (maximum cold-induced metabolic rate) in winter relative to summer. However, relatively large increases in cold tolerance can occur with only minor increments of maximum cold-induced metabolic rate and geographic variation in cold tolerance is not always positively correlated with variation in maximum cold-induced metabolic rate. Thus, it is uncertain whether maximum cold-induced metabolic rate and cold tolerance are phenotypically correlated in small birds and no previous study has directly examined this relationship. I measured maximum cold-induced metabolic rate and cold tolerance (i.e., thermogenic endurance) over three winters in black-capped chickadees Poecile atricapillus, American tree sparrows Spizella arborea, and dark-eyed juncos Junco hyemalis. For raw thermogenic endurance data, residuals of maximum cold-induced metabolic rate and thermogenic endurance from mass regressions were significantly and positively correlated in juncos and tree sparrows, and their correlation approached significance for chickadees. Log10 transformation of thermogenic endurance and mass data gave similar results. These data provide the first direct evidence for a phenotypic correlation between maximum cold-induced metabolic rate and thermogenic endurance in small birds, although much of the variance in thermogenic endurance is explained by factors other than maximum cold-induced metabolic rate and the degree of correlation differs among species. Nevertheless, these data suggest that physiological adjustments producing elevated thermogenic endurance also produce elevated maximum cold-induced metabolic rate in small birds.

Acclimatization↗
PubMed2000

Time course for cryoprotectant synthesis in the freeze-tolerant chorus frog, Pseudacris triseriata.

Increases in liver glycogen phosphorylase activity, along with inhibition of glycogen synthetase and phosphofructokinase-1, are associated with elevated cryoprotectant (glucose) levels during freezing in some freeze-tolerant anurans. In contrast, freeze-tolerant chorus frogs, Pseudacris triseriata, accumulate glucose during freezing but exhibit no increase in phosphorylase activity following 24-h freezing bouts. In the present study, chorus frogs were frozen for 5- and 30-min and 2- and 24-h durations. After freezing, glucose, glycogen, and glycogen phosphorylase and synthetase activities were measured in leg muscle and liver to determine if enzyme activities varied over shorter freezing durations, along with glucose accumulation. Liver and muscle glucose levels rose significantly (5-12-fold) during freezing. Glycogen showed no significant temporal variation in liver, but in muscle, glycogen was significantly elevated after 24 h of freezing relative to 5 and 30 min-frozen treatments. Hepatic phosphorylase a and total phosphorylase activities, as well as the percent of the enzyme in the active form, showed no significant temporal variation following freezing. Muscle phosphorylase a activity and percent active form increased significantly after 24 h of freezing, suggesting some enhancement of enzyme function following freezing in muscle. However, the significance of this enhanced activity is uncertain because of the concurrent increase in muscle glycogen with freezing. Neither glucose 6-phosphate independent (I) nor total glycogen synthetase activities were reduced in liver or muscle during freezing. Thus, chorus frogs displayed typical cryoprotectant accumulation compared with other freeze-tolerant anurans, but freezing did not significantly alter activities of hepatic enzymes associated with glycogen metabolism.

Adaptation, Physiological↗
PubMed2000

Characteristics of veal calves upon arrival, at 28 and 84 days, and at end of the production cycle.

Holstein bull calves arriving at five special-fed veal farms (eight production groups) were scored for various physical condition traits and blood-sampled within 2 h after arrival and at 28 d, 84 d, and 1 wk prior to slaughter at 116 to 143 d. Of 1179 total calves in the production groups, 758 calves were scored and evaluated. Blood cell analyses (red and white blood cell counts, hemoglobin, and packed cell volume) were conducted at all four sampling times; total serum protein concentration was obtained at 0 and 28 d. The study was initiated in autumn and ended the following autumn. Mean initial and final body weights were 46.3+/-0.17 and 209.7+/-0.77 kg; mean mortality was 2.5%. Average daily gain of the eight groups ranged from 1.23 to 1.70 kg/d. Subjective scores of 5 = excellent to 1 = very poor condition were used to evaluate 16 different physical condition characteristics. With the exception of leg joint, hoof, and foot scores, most of the physical condition scores exhibited improvement during the first 28 d. Foot and leg impairments did not appear to hinder the ambulatory ability of the calves during the production period. Physical condition scores at d 0 and 28 were generally not related to numbers or types of medical treatments (enteric, respiratory, other, or total) or to average daily gain during the production period. Means for most erythrocytic and leukocytic traits upon arrival (d 0) were within normal ranges, although 27.4% of the calves were clinically or marginally anemic. Final mean hemoglobin and packed cell volume were 8.53 g/dl and 26.1%. Forty-three percent of the calves at d 0 were colostral deficient, assuming that total serum protein concentrations of <5.5 g/dl indicate colostral deficiency. No blood trait was consistently correlated with body weight gain when gain during the production period was divided into quartiles and the blood traits were averaged by gain quartile. Calves in the lowest serum total protein quartile (mean 4.58 g/dl) had more respiratory and total medical treatments than quartiles with higher total protein means. Dairy bull calves arriving at veal production units after transporting from the dairy farm to the auction market (or other collection facility) have several physical impairments. However, most of these physical impairments are improved early in the veal feeding period and are not generally related to subsequent growth rate or medical treatment.

Aging↗
PubMed1999

Implant sequence effects in intact male Holstein veal calves: live and slaughter traits.

Seven sequences of growth promotant implants were used in special-fed intact male Holstein veal calves (n = 443). Calves received implants 4 d after arrival at the veal barn, 42, and 84. The following implants were used: placebo (0), Z (36 mg zeranol), ET (20 mg estradiol, 200 mg testosterone), EP/2 (10 mg estradiol, 100 mg progesterone), EP (20 mg estradiol, 200 mg progesterone), and EBA (24 mg estradiol, 120 mg trenbolone acetate). The following sequences were compared: 0-0-0 (negative control), 0-ET-ET, Z-ET-ET, 0-EP-EP, Z-EP-EP, 0-EP/2-EBA, and Z-0-EBA. From 0 to 42 d, Z implants increased (P<.05) ADG by 3.4% compared to placebo. However, implant schemes without an initial Z implant (0-ET-ET and 0-EP-EP) had higher (P<.05) mean ADG for the period from d 42 to 84. From 84 d to the end of the experiment, only the 0-EP/2-EBA treatment increased (P<.05) ADG compared to 0-0-0. Over the entire trial 0-ET-ET, 0-EP-EP, Z-EP-EP, and 0-EP/2-EBA implant sequences increased (P<.05) ADG by 3.2, 3.2, 2.4, and 4.7%, respectively, compared to the 0-0-0 sequence. Blood traits measured within 2 wk before slaughter were not affected by implant sequence, except that sequences with EP had higher (P<.05) leukocyte counts than were observed for the other sequences. Testicular weight was less (P<.01) for all of the implant sequences than for the negative control and less (P<.05) for Z-ET-ET than for 0-ET-ET, 0-EP-EP, 0-EP/2-EBA, and Z-0-EBA. The type and frequency of medical treatments did not differ among implant sequences for any of the 42-d phases, or over the entire trial. Generally, the growth promotant implants currently approved for beef cattle resulted in approximately 50% of the increase in growth rate in Holstein intact bull calves, as has been observed in beef-type steers or heifers.

Animals↗
PubMed1999

Implant sequence effects in intact male Holstein veal calves: carcass characteristics.

Seven sequences of growth promotant implants were used in intact male Holstein veal calves (n = 443). Implants were administered on d 0 (within 4 d after arrival at the veal barn), 42, and 84. The implants used were placebo (0), Z (36 mg zeranol), ET (20 mg estradiol, 200 mg testosterone), EP/2 (10 mg estradiol, 100 mg progesterone), EP (20 mg estradiol, 200 mg progesterone), and EBA (24 mg estradiol, 120 mg trenbolone acetate). The following sequences were compared: 0-0-0 (negative control), 0-ET-ET, Z-ET-ET, 0-EP-EP, Z-EP-EP, 0-EP/2-EBA, and Z-0-EBA. Sequences 0-EP-EP, Z-EP-EP, and 0-EP/2-EBA increased (P<.05) carcass weight from 3.3 to 3.9% compared to nonimplanted controls. There were no differences (P>.05) in percentage of carcass weight accounted for by the fore vs. rear halves of carcasses, suggesting there was no difference in the distribution of weight. Although there were differences in longissimus area, the results were not consistent, except that there was a trend for longissimus area to be increased by the use of estrogenic-androgenic implants (ET and EBA). There were no differences among implant sequences for carcass conformation, fat cover, muscle texture, marbling/ feathering, muscle color, or muscle chemical composition. Of four implant sequences (0-0-0, 0-ET-ET, 0-EP-EP, and 0-EP/2-EBA) tested for differences in Warner-Bratzler shear force tenderness, the latter two sequences averaged higher (P<.05) for shear force than did the negative control. These results suggest that aggressive implant strategies in young, intact Holstein bull calves (raised as veal) have minimal effects on carcass characteristics.

Animals↗
PubMed1997

Diagnosis of proliferative enteritis in frozen and formalin-fixed, paraffin-embedded tissues from a hamster, horse, deer and ostrich using a Lawsonia intracellularis-specific multiplex PCR assay.

Proliferative enteritis (PE) is an enteric disease that has been reported in a variety of animals. It is caused by an obligate intracellular bacterium identified in swine as Lawsonia intracellularis. The organism can be detected ante-mortem in swine with PE using molecular diagnostic methods. The disease can be diagnosed post-mortem in all species by gross examination of tissues and special histologic staining procedures. In this study we extracted total DNA from frozen or formalin-fixed, paraffin-embedded tissues from cases of pig, hamster, horse, deer and ostrich PE. The samples were subjected to a multiplex PCR reaction using primers specific for a swine isolate of L. intracellularis. Identical sized PCR products were detected in samples from all animals with PE and the specificity of the PCR reaction for L. intracellularis was demonstrated by Southern-blotting and hybridization using specific probes. These results suggest that the intracellular organism of PE in these species are all very closely related to the causative agent of PE in swine, L. intracellularis. In addition, this multiplex PCR assay can be used to detect the organism in frozen or archival tissues, facilitating retrospective diagnosis of PE.

Animals↗
PubMed1997

Comparison of the 16S ribosomal DNA sequences from the intracellular agents of proliferative enteritis in a hamster, deer, and ostrich with the sequence of a porcine isolate of Lawsonia intracellularis.

Proliferative enteritis is an enteric disease that affects a variety of animals. The causative agent in swine has been determined to be an obligate intracellular bacterium, Lawsonia intracellularis, related to the sulfate-reducing bacterium Desulfovibrio desulfuricans. The intracellular agents found in the lesions of different animal species are antigenically similar. In addition, strains from the pig, ferret, and hamster have been shown to be genetically similar. In this study we performed a partial 16S ribosomal DNA sequence analysis on the intracellular agent of proliferative enteritis from a hamster, a deer, and an ostrich and compared these sequences to that of the porcine L. intracellularis isolate. Results of this study indicate that the intracellular agents from these species with proliferative enteritis have high sequence similarity, indicating that they are all in the genus Lawsonia and that they may also be the same species, L. intracellularis.

Animals↗
PubMed1996

Freezing tolerance/intolerance and cryoprotectant synthesis in terrestrially overwintering anurans in the Great Plains, USA.

Mechanistic bases for freezing tolerance in anurans have been well-studied only in wood frogs, Rana sylvatica, so comprehensive explanations for the mechanisms and evolution of freezing tolerance in anurans are lacking. We measured crystallization temperatures, freezing tolerance/intolerance, and tissue glucose and glycogen phosphorylase activities in frozen and unfrozen winter-acclimated Pseudacris triseriata, Bufo cognatus and B. woodhousei. Freezing occurred at higher subzero temperatures on wet substrate than on dry substrate in all species, indicating susceptibility to inoculative freezing. P. triseriata was freeze-tolerant, but survival was dependent on the level of supercooling prior to freezing. All Bufo were freezing intolerant, regardless of crystallization temperature. Glucose was significantly elevated by freezing in both liver (35-fold) and leg muscle (22-fold) in winter P. triseriata, but only liver glucose was significantly elevated in B. cognatus. However, freezing did not alter glycogen phosphorylase activity in either species. Liver phosphorylase activity was significantly higher in P. triseriata than in B. cognatus, suggesting that capacity for mobilizing glucose from liver glycogen is associated with freezing tolerance. Summer measurements of liver phosphorylase activity, however, did not differ between species. Thus, P. triseriata, but not B. cognatus, exhibited winter increment of liver phosphorylase activity that is correlated with the development of freezing tolerance.

Acclimatization↗
PubMed1992

Leg ulcers.

Explore the source record for details and available documents.

Diuretics↗
PubMed1992

Colonization of rabbits by Pasteurella multocida: serum IgG responses following intranasal challenge with serologically distinct isolates.

Enzyme-linked immunosorbent assays (ELISAs) and immunoblots were used to measure serum IgG responses in rabbits which were intranasally challenged with Pasteurella multocida. The responses to two serologically distinct isolates (isolate 1, serotype 3:A and isolate 10, serotype 1:D) were compared and then correlated with the ability of the isolates to colonize the nasal passages. Five rabbits were challenged with each isolate (10(5) CFU); nasal washings and sera were collected weekly for 8 weeks. Serum IgG levels were measured by ELISA and immunoblots, using bacterial whole cells and lipopolysaccharides (LPSs) as antigens. The serum IgG response to isolate 1 was evident earlier and was significantly stronger than the response to isolate 10 (P less than 0.025). Immunoblots supported this observation and confirmed that both isolates elicited antibodies which reacted with bacterial protein and LPS antigens, with antibody to protein detectable before antibody to LPS. Results of weekly nasal cultures suggested that the antibody response data could be explained by a difference in the ability of the isolates to colonize the nasal passages: isolate 1 was recovered from four of five rabbits for 8 weeks, whereas isolate 10 was recovered for a maximum of 2 weeks, even when the challenge dose was increased tenfold. The strong response elicited by isolate 1 was therefore probably a result of persistent colonization, whereas the weak response to isolate 10 may have resulted from an inability to persistently colonize the nasal passages. The results of this study demonstrate that isolates of P. multocida elicit antibody responses of differing intensities and vary in their ability to colonize the nasal passages.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Intranasal↗
PubMed1991

Embolic abscesses in hereditary hemorrhagic telangiectasia.

Hereditary hemorrhagic telangiectasia is an inherited disorder in which patients may have multiple telangiectases and arteriovenous fistulas in the skin and internal organs. Patients can suffer from a variety of serious clinical complications, including abscess formation. We report two patients in whom neurologic symptoms developed from embolic abscesses, one for whom this complication was fatal. The reported incidence and microbiologic features of this complication are similar to that of endocarditis in patients with valvular heart disease. We believe that patients with hereditary hemorrhagic telangiectasia should receive similar antibacterial prophylaxis for procedures placing them at risk for bacteremia.

Abscess↗
PubMed1984

A dermatitis-eosinophilia syndrome. Treatment with methylprednisolone pulse therapy.

A 47-year-old man had a generalized, eczematous erythroderma and eosinophilia one week after a wasp sting. These changes persisted for four months despite intensive topical therapy and oral corticosteroids. He was then given corticosteroid pulse therapy with methylprednisolone sodium succinate (2 g, intravenously). One week later, a second pulse treatment was administered. This therapy was followed by permanent resolution of the dermatitis within two weeks.

Adrenocorticotropic Hormone↗
PubMed1983

Methylprednisolone inhibits pemphigus acantholysis in skin cultures.

Glucocorticosteroids are used to treat patients with pemphigus, but the mechanism of action is unknown. We studied the effect of methylprednisolone on acantholysis induced in vitro by incubation of normal skin with plasma from a patient with pemphigus. Normal human breast skin was maintained in organ cultures for several days in Ham F-10 medium. Plasma from a patient with active pemphigus vulgaris caused suprabasilar epidermal acantholysis when added to this culture system. In control cultures (F-10 medium and fetal bovine serum), no acantholysis occurred. Acantholysis was prevented when breast skin was preincubated for 24 h in a 0.25 mM solution of methylprednisolone in F-10 medium and fetal bovine serum, suggesting that methylprednisolone directly inhibits acantholysis. No suppression of acantholysis occurred when the methylprednisolone was added to the culture system simultaneously with the pemphigus plasma, suggesting a time requirement for alteration of cellular events. The inhibition of acantholysis was not caused by cell death since methylprednisolone did not alter keratinocyte viability as determined by exclusion of trypan blue dye when keratinocytes were exposed to pemphigus plasma. Similarly, the inhibition of acantholysis was not due to dissolution, alteration, or coating of pemphigus antigen on epidermal cells, since the intercellular antibodies in the plasma bound as well to methylprednisolone-treated epidermis as to untreated epidermis.

Acantholysis↗
PubMed1981

Pemphigus vulgaris and plasma exchange: clinical and serologic studies.

A woman with pemphigus vulgaris was treated by plasma exchange. Four separate exchanges of approximately 4,000 ml each were performed over a 2-week period. The patient's pemphigus antibody titer decreased from 1/320 before the first exchange to 1/20 after the final exchange, and no new lesions developed for 3 weeks following treatment. It is likely that treatment with plasma exchange helped induce clinical and laboratory remission. The fall in pemphigus antibody titer correlated to loss of acantholytic activity of plasma in vitro. Acantholysis developed in cultures of normal human skin and preexchange plasma but was undetectable in culture of human skin and preexchange plasma diluted to postexchange pemphigus antibody titer. Plasma exchange is a rational approach to management of severe pemphigus but is not practical for routine management.

Adult↗
PubMedDate not supplied

Evidence for a proximate influence of winter temperature on metabolism in passerine birds.

The roles of ultimate and proximate factors in regulating basal and summit metabolic rates of passerine birds during winter have received little study, and the extent to which winter temperatures affect these variables is unknown. To address this question, we measured basal and summit (maximum cold-induced) metabolic rates in black-capped chickadees (Poecile atricapillus), dark-eyed juncos (Junco hyemalis), and American tree sparrows (Spizella arborea) during winters from 1991/1992 to 1997 in southeastern South Dakota. Both temperature and these metabolic rates varied within and among winters. Least-squares regression revealed significant negative relationships for normalized basal and summit metabolism against mean winter temperature for all species pooled (R2=0.62 to 0.69, P</=0.001). Simple and multiple regressions were performed to analyze the influence of short-term (0-7 d preceding testing), medium-term (14-30 d before testing), and long-term (100-yr means for mean, minimum, and extreme low temperatures) temperature variables on whole-animal and mass-specific metabolic rates. Simple correlation coefficients for whole-animal metabolic rates were highest (r=-0.48 to -0.75, P<0.01) for 14-30-d temperature variables in chickadees and juncos and for 0-5-d temperature variables (r=-0. 54 to -0.68, P<0.01) in tree sparrows. For mass-specific metabolic rates, simple correlation coefficients were again highest (r=-0.45 to -0.70, P<0.01) for 14-30-d temperature variables in chickadees and juncos. Simple correlations for mass-specific metabolic rates were highest for 7-14-d temperature variables for tree sparrows (r=-0.67 to -0.68, P<0.01). Multiple regressions yielded model R2s ranging from 0.45 to 0.94 using a forward selection procedure and from 0.23 to 0.71 using a stepwise selection procedure. The partial R2 contributed from mass variation was small in all cases, ranging from 0.05 to 0.18, indicating that winter temperature was generally a good predictor of metabolic rate in these species. Metabolism was substantially correlated with short- and medium-term temperature variables for all species (cumulative partial R2=0.31 to 0.70 for forward selection and 0.13 to 0.57 for stepwise selection) but, at most, only weakly so with long-term temperature variables (cumulative partial R2=0-0.11 for forward selection and 0-0.06 for stepwise selection). Thus, short- to medium-term temperatures were better predictors of metabolic rates than long-term temperatures. These data suggest a proximate role for winter temperature in regulating metabolism in these birds.

Adaptation, Physiological↗