Severe Biliary Hyperplasia Associated with Liver Fluke Infection in an Adult Alpaca

An adult alpaca ( Lama pacos) had a locally extensive area of hepatic atrophy involving the right lobe. Grossly, the atrophic lobe was light tan and firm and contained small, raised, white to yellow, partially mineralized circular nodules predominantly at the periphery of the atrophic tissue. Microscopically, viable hepatocytes were not present in the atrophic area, and the tissue consisted of diffuse biliary epithelial proliferation without any evidence of nuclear or cellular atypia or the presence of mitotic figures. The circular mineralized nodules consisted of granulomatous inflammation with intralesional parasitic ova surrounded by fibrous connective tissue. Morphologically, the ova were compatible with those of Fasciola hepatica. The severe biliary hyperplasia was unusual, and it was not clear whether it was caused by an aberrant host response to the parasitic infection or whether it was an unrelated event.

Copy number variation in the human Y chromosome in the UK population

We have assessed copy number variation (CNV) in the male-specific part of the human Y chromosome discovered by array comparative genomic hybridization (array-CGH) in 411 apparently healthy UK males, and validated the findings using SNP genotype intensity data available for 149 of them. After manual curation taking account of the complex duplicated structure of Y-chromosomal sequences, we discovered 22 curated CNV events considered validated or likely, mean 0.93 (range 0–4) per individual. 16 of these were novel. Curated CNV events ranged in size from <1 kb to >3 Mb, and in frequency from 1/411 to 107/411. Of the 24 protein-coding genes or gene families tested, nine showed CNV. These included a large duplication encompassing the AMELY and TBL1Y genes that probably has no phenotypic effect, partial deletions of the TSPY cluster and AZFc region that may influence spermatogenesis, and other variants with unknown functional implications, including abundant variation in the number of RBMY genes and/or pseudogenes, and a novel complex duplication of two segments overlapping the AZFa region and including the 3′ end of the UTY gene.

Effect of dopamine agonists or antagonists, TRH, stress and piglet removal on plasma prolactin concentrations in lactating gilts

The effect of dopamine agonists (ergocryptine), antagonists (chlorpromazine, haloperidol, reserpine, pimozide), thyrotropin releasing hormone or stress (restraint, piglet removal) on prolactin release was studied in primiparous lactating gilts. All animals were fitted with surgically implanted jugular catheters before farrowing. The only drug treatments which resulted in a significant change in PRL concentrations in blood were thyrotropin releasing hormone (increase) and ergocryptine (decrease). The results suggest that dopamine may not be the only regulator of prolactin in lactating pigs. Further studies are needed to identify drugs which would be useful in clinical situations for treatment of lactation failure due to low prolactin secretion. In the two stress-exposed groups, there was a gradual, steady decline in the plasma concentration of prolactin which resulted from loss of suckling contact with the piglets. Thus, snare restraint does not increase prolactin secretion in lactating sows confirming the results of other studies on pigs in different physiologic states.

Seasonal changes in serum calcium, phosphorus, and vitamin D concentrations in llamas and alpacas

OBJECTIVE

To evaluate the interaction of season and age on serum calcium, phosphorus, and vitamin D3 concentrations in llamas and alpacas.

ANIMALS

23 clinically normal llamas and 7 alpacas.

PROCEDURES

Animals were assigned to 1 of the 3 following groups on the basis of age at the start of the study: adult (age, > or = 24 months; n = 8), yearling (> 12 but < 20 months; 5), and neonate (< 6 months; 17). Twelve serum samples were obtained at monthly intervals. Calcium, phosphorus, and vitamin D3 concentrations were measured, and the calcium-to-phosphorus concentration (Ca:P) ratio calculated. Effect of season and age on each of these variables was determined.

RESULTS

Vitamin D3 concentrations varied significantly as a function of season; the highest and lowest concentrations were detected September through October and February through March, respectively. The seasonal decrease in vitamin D3 concentration was significantly greater in neonates and yearlings, compared with adults. Serum phosphorus concentration decreased as a function of age, with the most significant seasonal change detected in the neonate group. The Ca:P ratio in neonates varied between 1.1 and 1.3 except during winter months when it increased to > or = 2.0.

CONCLUSIONS AND CLINICAL RELEVANCE

Mean vitamin D3 concentration varied by > 6 fold in neonatal and yearling llamas and alpacas and > 3 fold in adult animals as a function of season. These results support the hypothesis that seasonal alterations in vitamin D3 concentrations are a key factor in the development of hypophosphatemic rickets in llamas and alpacas.

Metabolic changes and induction of hepatic lipidosis during feed restriction in llamas

OBJECTIVES

To determine whether feed restriction induces hepatic lipidosis (HL) in llamas and to evaluate the metabolic changes that develop during feed restriction.

ANIMALS

8 healthy adult female llamas.

PROCEDURE

Llamas were fed grass hay at a rate of 0.25% of their body weight per day for 13 to 28 days. Llamas were monitored by use of clinical observation, serum biochemical analyses, and ultrasound-guided liver biopsies.

RESULTS

All 8 llamas lost weight and mobilized fat. Five llamas developed HL, including 4 that were nursing crias. During the period of feed restriction, mean serum concentration of bile acids and activities of aspartate aminotransferase (AST), sorbitol dehydrogenase (SDH), and gamma-glutamyl transferase (GGT) were significantly higher in llamas that developed HL, compared with llamas that did not. Mean insulin-to-cortisol concentration ratios were lower in llamas with HL before and up to 7 days of feed restriction, compared with those that did not develop HL.

CONCLUSIONS AND CLINICAL RELEVANCE

HL in llamas may be induced by severe feed restriction, particularly in the face of increased energy demand. Llamas with weight loss attributable to inadequate dietary intake may develop biochemical evidence of hepatopathy and HL. Increases in serum concentration of bile acids and activities of GGT, AST, and SDH may indicate the development of HL in llamas and identify affected animals for aggressive therapeutic intervention.

Glucose tolerance testing in llamas and alpacas

OBJECTIVE

To determine blood glucose clearance in 2 species of New World camelids after IV challenge and to examine mechanisms of this clearance.

ANIMALS

5 adult female llamas and 5 adult gelded alpacas.

PROCEDURE

After food was withheld for 12 hours, camelids received 0.5 g of glucose/kg of body weight by rapid IV infusion. Serum concentrations of glucose, nonesterified fatty acids, cortisol, and insulin, and plasma concentrations of lactate were determined before and 0, 1, 2, 3, 4, 5, 15, 30, 60, 90, 120, 180, and 240 minutes after infusion. Ratios of insulin to glucose and insulin to cortisol were calculated for each time point.

RESULTS

Postinfusion glucose concentrations were significantly higher in llamas than alpacas for the first 15 minutes and remained significantly higher than baseline values in both species for 180 minutes. Lactate and cortisol concentrations did not change significantly; nonesterified fatty acid concentrations decreased in both species 30 minutes after infusion. Baseline insulin concentrations were < 6 microU/ml in both species and increased only to 10.1 +/- 0.7 microU/ml in llamas. Insulin concentrations did not change significantly in alpacas.

CONCLUSIONS AND CLINICAL RELEVANCE

Llamas and alpacas clear glucose more slowly than other domestic species after challenge, mainly because of a weak insulin response and slow cellular uptake. This response may impair the assimilation of exogenous glucose as well as make llamas and alpacas prone to diabetes-like disorders when an abundance of endogenous or exogenous glucogenic agents are present.

Pharmacokinetics and pharmacodynamics of antiulcer agents in llama

Plasma concentration time curves following intravenous (i.v.) administration of 1.5 mg/kg of ranitidine, 0.2 mg/kg, 0.4 mg/kg and 0.8 mg/kg of omeprazole, respectively, were analysed in six llamas. Plasma profiles after i.v. administration of both drugs showed plasma concentrations declining in a biexponential manner with a rapid distribution phase. Pharmacokinetics parameters after ranitidine administration to six llamas showed a mean elimination half-life of 1.53 +/- 0.26 h. The mean volume of distribution (Vdss) in llamas was 1.77 +/- 0.31 L/kg, and mean body clearance in llamas was 0.778 +/- 0.109 L/kg/h. Ranitidine produced only a small transitory (<1 h) decline in acid production when administered i.v. at a dose of 1.5 mg/kg. Omeprazole showed dose-dependent nonlinear pharmacokinetics. The mean half-life of 0.2 mg/kg i.v. omeprazole was shorter than that of 0.4 and 0.8 mg/kg i.v. omeprazole, i.e. 0.61, 0.72 and 1.07 h, respectively. The area under the curve (AUC) and mean residence time (MRT) increased with increasing dose, while clearance decreased as dose increased. The decline in acid production following 0.2 mg/kg i.v. omeprazole was highly variable and did not produce a clinically useful suppression of third compartment acid production. In contrast, both 0.4 mg/kg and 0.8 mg/kg omeprazole i.v. administration significantly reduced third compartment acid production. The reduction in acid production following 0.8 mg/kg omeprazole was not significantly greater than the reduction observed following 0.4 mg/kg dosage. Misoprostol (10 microg/kg) was administered i.v. in an absolute alcohol solution. Two animals collapsed following drug administration. While the side-effects could have been produced by either misoprostol or the alcohol vehicle, the clinical changes were more consistent with an adverse drug reaction. Unfortunately, the limitation of UV detection did not provide the sensitivity needed to quantify the amount of misoprostol in llama plasma, and the pharmacokinetics could not be evaluated.

Pathogenesis of Streptococcus zooepidemicus infection after intratracheal inoculation in llamas

OBJECTIVES

To test whether generalized Streptococcus zooepidemicus infection could be induced by intratracheal inoculation in llamas and to characterize this infection.

ANIMALS

6 test and 3 control llamas.

PROCEDURE

Test llamas received 1 of 3 dosages of S. zooepidemicus by intratracheal injection, whereas control llamas received sterile culture medium. Physical examination variables and results of clinicopathologic analyses of blood, peritoneal fluid, and tracheal wash fluid were compared in test llamas between, before, and during the development of bacteremia and with control llamas. Bacteriologic culture was performed on all collected body fluids and tissue specimens that were collected at necropsy. Tissue specimens that were collected at necropsy were examined histologically.

RESULTS

Infection induced fever, anorexia, and signs of depression. Five of 6 infected llamas developed specific signs of inflammation in the thorax or abdomen, bacteremia, neutrophilic leukocytosis with toxic changes and high band neutrophil cell counts, hyperfibrinogenemia, and high peritoneal fluid WBC counts and protein concentrations. On development of bacteremia, llamas had significant decreases in serum iron (from 118+/-25 to 6+/-4 microg/ml) and increases in serum glucose (from 131+/-5 to 253+/-48 mg/dl) concentrations.

CONCLUSIONS AND CLINICAL RELEVANCE

Streptococcus zooepidemicus spreads rapidly to other body compartments after intratracheal inoculation in llamas. Fever, anorexia, and signs of depression are the most consistent clinical signs, although other signs are possible. Clinicopathologic analysis of body fluids yields evidence of inflammation. Infection by S. zooepidemicus can be proven by bacteriologic culture of body fluids before death or of tissue specimens after death.

Use of cloprostenol as an abortifacient in the llama (Lama glama)

As part of a larger project investigating the development and heritability of choanal atresia glama), it was necessary to develop a protocol for aborting llamas at various stages of gestation. Twenty-seven animals between 4 and 7 mo of gestation were successfully aborted a total of 53 times following two 250 microg intramuscular injections of cloprostenol at 24 h intervals. Abortion was induced once in 10 animals and multiple times (range 2 to 5) in 17 animals. Twenty-four animals (45.2%) aborted 3 d following the first injection, with 20 animals (37.7%) aborting 4 d post prostaglandin administration. Other animals aborted at 2 d (n=6, 11.3%), 5 d (n=2, 3.8%), and 7 d (n=1, 1.9%) following drug administration. Forty-nine (92.5%) of the abortions occurred following a single series of injections, while 4 animals (7.5%) aborted following a second series of injections. No confirmed pregnant animals failed to abort following the second series of cloprostenol injections. Conception rates in animals rebred 2 to 4 wk following an abortion were comparable to those of untreated animals in the research herd. Unlike the severe hypertension and death that has been reported following dinoprost tromethamine administration in the llama, no adverse reactions were observed in this study following cloprostenol administration. The results demonstrate that llamas can be safely and effectively aborted up to 7 mo of gestation (normal full term gestation = 342 +/- 10 days) without adverse effects on subsequent fertility.

Specificity of four serologic assays for Mycobacterium avium ss paratuberculosis in llamas and alpacas: a single herd study

An investigation was conducted for Mycobacterium avium ss paratuberculosis infections in a research herd of llamas and alpacas. Herd culture-negative status was established over a 23-month period by screening any individuals with any signs compatible with paratuberculosis (n = 1), high serology values (n = 8), or other health and research related reasons (n = 24). There were no M. avium ss paratuberculosis isolates from radiometric cultures of multiple tissue and fecal samples from these individuals and no known sources of exposure. Paratuberculosis is uncommon in North American llamas and alpacas: only 5 cases were identified after an extensive search of the Veterinary Medical Data Base, diagnostic laboratory records, publication databases, and personal communications. Therefore, serum samples from llamas (n = 84) and alpacas (n = 16) in the culture-negative herd were used to obtain preliminary estimates of test specificity for 3 enzyme-linked immunoassays (ELISAs) and an agar gel immunodiffusion (AGID) assay kit for detecting serum antibodies to M. avium ss paratuberculosis in South American camelids. The ELISAs were modifications of established bovine assays for antibody detection. With provisional cutoffs, ELISA-A had 52 false positives (specificity 48%), ELISA-B had 8 false positives (specificity 92%), ELISA-C had two false positives (specificity 98%), and the AGID had 0 false positives (specificity 100%). The range of ELISA values for culture-positive llamas and alpacas (n = 10) from other herds overlapped the range of values for culture-negative llamas and alpacas. The accuracy of the ELISAs may be improved by using age- and sex-specific cutoffs because uninfected male llamas and alpacas that were older than 1 year had higher values for some tests. These tests can be used for either llamas or alpacas; the protein-G conjugate ELISA (ELISA-B) may be useful for multispecies applications. These assays are best used for rapid presumptive diagnoses of llamas and alpacas with diarrhea and weight loss and as a screening tool for herds known to be exposed to infection. All seropositive results should be confirmed with culture.

Radiographic contrast gastrointestinal study of the neonatal llama

This is a description of the radiographic appearance of the normal gastrointestinal tract of neonatal crias with survey and contrast radiography, including transit times for the various segments of the gastrointestinal tract. Radiographs of the abdomen of six healthy neonatal llama crias positioned in right lateral and dorsal recombency were obtained initially then at various intervals post barium administration. Portions of the gastrointestinal tract that could be identified included the stomach with first, second and third compartments, the duodenal ampulla, small intestine, proximal loop of the ascending colon, spiral colon and descending colon. Barium given by orogastric intubation rapidly entered all three compartments of the stomach and the proximal small intestine. Overall the transit time through the intestinal tract of the crias was longer than expected with no emptying of the ascending colon and beyond though studies were carried to 48-72 hours. Recommendations are made for frequency of radiographs.

Hepatic lipidosis in llamas and alpacas: 31 cases (1991-1997)

OBJECTIVE

To identify factors associated with hepatic lipidosis (HL) in llamas and alpacas.

DESIGN

Retrospective case series.

ANIMALS

30 llamas and 1 alpaca.

PROCEDURES

Medical records were searched to identify llamas or alpacas in which a histologic diagnosis of HL was made. Information was retrieved on signalment, history, clinical and laboratory findings, and results of necropsy or examination of biopsy specimens. Data were analyzed using descriptive statistics and chi 2 analyses.

RESULTS

Females were affected more often than males; however, the sex distribution was not different from that of the camelid population in the diagnostic laboratory's database. Fifty-four percent of the females were pregnant, and 46% were lactating. Most affected camelids were 6 to 10 years old. Anorexia and recent weight loss were common (51.6% of camelids). An infective agent was found in only one ilama, and toxins and mineral deficiencies were not identified. The most common abnormalities on serum biochemical analysis were a high concentration of bile acids, high activities of gamma-glutamyltransferase (GGT) and aspartate aminotransferase (AST), and hypoproteinemia. Concentrations of nonesterified fatty acids (NEFA) and beta-hydroxybutyrate (beta-HB) were high in those camelids in which these compounds were assayed. Twenty-nine camelids did not survive.

CLINICAL IMPLICATIONS

Sick camelids should be considered at risk for developing HL, especially those with anorexia or the metabolic demands of pregnancy and lactation. Other stresses also appear to contribute. High concentrations of NEFA, beta-HB, and bile acids; high activities of GGT and AST; and hypoproteinemia may indicate that HL has developed.

Blood mineral and vitamin E concentrations in llamas

OBJECTIVE

To establish reference values for blood concentrations of total calcium (Ca), inorganic phosphorus (P), iron (Fe), copper (Cu), zinc (Zn), selenium (Se), and vitamin E (Vit E) in clinically normal llamas.

ANIMALS

270 llamas ranging in age from < 1 month to > 15 years and grouped by age, sex, pregnancy status, and stage of gestation. Selected llamas were from 21 farms in Oregon, did not have previous health problems, and met specific health criteria on examination.

PROCEDURE

Serum and blood samples were obtained and analyzed for concentrations of Ca, P, Fe, Cu, Se, Zn, and Vit E, and total iron binding capacity (TIBC) and percentage of transferrin saturation (% Sat). Mean differences by age, sex, pregnancy status, and stage of gestation, as well as all interactions, were compared to establish reference values.

RESULTS

Mean values and reference ranges for most of the minerals and vitamins were similar to previously reported values. Male versus female differences were not identified for any measurements. Age was a significant variable for Ca, P, Fe, and Se concentrations, as well as Ca-to-P ratio and TIBC. Identified age-based effects were modeled by use of linear regression. Copper and Zn concentrations and % Sat did not differ as a function of age. Serum Vit E concentration was influenced by an age by sex interaction and stage of gestation.

CONCLUSIONS

Age was found to be an important variable influencing many blood nutrient concentrations in healthy llamas.

CLINICAL RELEVANCE

Clinical diagnosis of metabolic disease may be improved with use of age-based reference values, especially for neonates.

Normal reference intervals and the effects of time and feeding on serum bile acid concentrations in llamas

Fifty clinically healthy llamas, 0.5-13 years of age (22 intact males, 10 neutered males, 18 females), with no biochemical evidence of liver disease or hematologic abnormalities, were selected to establish serum bile acid reference intervals. Serum samples submitted to the clinical pathology laboratory were analyzed using a colorimetric enzymatic assay to establish bile acid reference intervals. A nonparametric distribution of llama bile acid concentrations was 1-23 micromol/liter for llamas >1 year of age and 10-44 micromol/liter for llamas < or = 1 year of age. A significant difference was found between these 2 age groups. No correlation was detected between gender and bile acid concentrations. The reference intervals were 1.1-22.9 micromol/liter for llamas >1 year of age and 1.8-49.8 micromol/liter for llamas < or = 1 year of age. Additionally, a separate group of 10 healthy adult llamas (5 males, 5 females, 5-11 years of age) without biochemical or hematologic abnormalities was selected to assess the effects of feeding and time intervals on serum bile acid concentrations. These 10 llamas were provided fresh water and hay ad libitum, and serum samples were obtained via an indwelling jugular catheter hourly for 11 hours. Llamas were then kept from food overnight (12 hours), and subsequent samples were taken prior to feeding (fasting baseline time, 23 hours after trial initiation) and postprandially at 0.5, 1, 2, 4, and 8 hours. In feeding trials, there was no consistent interaction between bile acid concentrations and time, feeding, or 12-hour fasting. Prior feeding or time of day did not result in serum bile acid concentrations outside the reference interval, but concentrations from individual llamas varied within this interval over time.

An overview of selected diseases and drug needs in the llama and alpaca industries

The North American llama and alpaca industries will probably continue to expand at a rate of 20-25% per year for at least the next one to two decades. As a result, while the total population will always be small relative to the cattle and swine industries, the total numbers of alpacas and llamas will be substantial. Accordingly, it is appropriate and timely to begin the process of getting drugs approved for usage in these species. Four drugs that warrant consideration for NRSP-7 evaluation and approval are: Ivermectin for the prevention of P. tenuis infections. Chlorsulon for the treatment of Fasciola hepatica infections. Ceftiofur sodium for the treatment of various bacterial infections. Omeprazole for the management and prevention of third compartment ulcers.

The disposition of five therapeutically important antimicrobial agents in llamas

The disposition of five therapeutic antimicrobial agents was studied in llamas (Lama glama) following intravenous bolus administration. Six llamas were each given ampicillin, tobramycin, trimethoprim, sulfamethoxazole, enrofloxacin and ceftiofur at a dose of 12 mg/kg, 1 mg/kg, 3 mg/kg, 15 mg/kg, 5 mg/kg, and 2.2 mg/kg of body weight, respectively, with a wash out period of at least 3 days between treatments. Plasma concentrations of these antimicrobial agents over 12 h following i.v. bolus dosing were determined by reverse phase HPLC. Disposition of the five antimicrobial agents was described by a two compartment open model with elimination from the central compartment, and also by non-compartmental methods. From compartmental analysis, the elimination rate constant, half-life, and apparent volume of distribution in the central compartment were determined. Statistical moment theory was used to determine noncompartmental pharmacokinetic parameters of mean residence time, clearance, and volume of distribution at steady state. Based on the disposition parameters determined, and stated assumptions of likely effective minimum inhibitory concentrations (MIC) a dose and dosing interval for each of five antimicrobial agents were suggested as 6 mg/kg every 12 h for ampicillin; 4 mg/kg once a day or 0.75 mg/kg every 8 h for tobramycin; 3.0 mg/kg/15 mg/kg every 12 h for trimethoprim/sulfamethoxazole; 5 mg/kg every 12 h for enrofloxacin; and 2.2 mg/kg every 12 h for ceftiofur sodium for llamas. Steady-state peak and trough plasma concentrations were also predicted for the drugs in this study for llamas.

Evaluation of vitamin D status of llamas and alpacas with hypophosphatemic rickets

OBJECTIVE

To evaluate vitamin D concentrations in juvenile llamas and alpacas with hypophosphatemic rickets.

DESIGN

Prospective cohort study.

ANIMALS

21 llamas (14 with rickets, 7 clinically normal) and 9 alpacas (6 with rickets, 3 clinically normal).

PROCEDURES

Blood samples were collected at the time of diagnosis and prior to the initiation of treatment. Serum concentrations of calcium, inorganic phosphorus, and 25-hydroxycholecalciferol (vitamin D3) were determined on all samples. Comparisons were completed for disease status, age, sex, species, month of birth, and all interactions.

RESULTS

Serum concentrations of phosphorus and vitamin D were lower in affected llamas and alpacas than in clinically normal llamas and alpacas, even when mean concentrations were adjusted for age differences. Species (llama or alpaca), sex, and age did not affect any of the metabolite concentrations within this study population. Month of birth influenced vitamin D concentrations and number of affected llamas and alpacas per month. The greatest number of affected llamas and alpacas was identified between January through March, suggesting a seasonal pattern to this syndrome. Treatment of affected llamas and alpacas with vitamin D resulted in increased concentrations of phosphorus and vitamin D. Serum phosphorus concentration was best predicted by 2 independent variables (serum vitamin D concentration and month of birth).

CLINICAL IMPLICATIONS

We believe vitamin D deficiency is the primary cause of hypophosphatemic-rickets of growing camelids, and the observed hypophosphatemia is secondary to a primary deficiency of vitamin D. Appropriate treatment with vitamin D supplements can correct hypophosphatemia and vitamin D deficiency in camelids.

Megaesophagus in 15 llamas: a retrospective study (1985-1993)

Megaesophagus was diagnosed in 15 llamas on the basis of survey and contrast radiography. Age of onset ranged from 13 months to 9.5 years. Clinical signs varied, with salivation being the most common; regurgitation or dysphagia were noted in only 33% of the cases. Duration of the disorder ranged from 1 week to 5 years. Organophosphate toxicity was the cause of megaesophagus in 1 llama. While most cases were of unknown etiology, the 3 with histological abnormalities included 1 with vagal neuropathy and 2 with a degenerative myopathy of esophageal muscles. The causes in most were undetermined.

Third compartment ulcers in the llama

The diagnosis of third compartment ulcers in the llama and alpaca is largely one of exclusion. Clinical signs may include mild to severe colic, inappetence, decreased fecal output, bruxism, and depression. Abdominocentesis results are usually unremarkable if C3 perforation has not occurred but reflective of a generalized peritonitis if full thickness ulceration has occurred. The H-2 receptor antagonists cimetidine and ranitidine do not suppress C3 acid production for a significant period of time and are of questionable efficacy in the management of C3 ulcers.

Suppression of prolactin and cytotoxic T-lymphocyte activity in PCB-treated mice

Halogenated aromatic hydrocarbons (HAH) are ubiquitous environmental contaminants. Studies in rats have shown that HAH treatment can lead to dysregulation of circulating hormone levels, including prolactin. Reduction of prolactin levels in both rats and mice is inhibitory to immune function. Previous studies have reported suppression of alloantigen-specific cytotoxic T-lymphocyte (CTL) activity in mice treated with 3,3', 4,4', 5,5'-hexachlorobiphenyl (HxCB). Here we report that treatment of mice with HxCB (10 mg/kg body weight) leads to a significant reduction of serum prolactin levels (by 89% to 3.7 ng/ml) on day 10 post alloantigen injection (P815 mastocytoma), the day of peak alloantigen-specific CTL activity. Prolactin levels were not altered on day 3 post alloantigen injection. Treatment with bromocriptine (5 mg/kg/day) reduced serum prolactin levels slightly on day 3 and significantly (94% to 2.1 ng/ml) on day 10 post alloantigen injection. Splenic CTL activity was not altered by treatment with bromocriptine. The data presented here suggest that reduction of prolactin levels alone, to the extent observed in HxCB-treated mice, is not causative for CTL suppression.

Evaluation of Janeway gastrostomy in llamas

To provide long-term gastric fistulas for collection of third-compartment gastric contents, Janeway mucosal tube gastrostomy was performed, using a gastrointestinal stapling instrument, in 6 castrated adult male llamas. Mean operative time (+/- SEM) was 65 +/- 4.16 minutes. All llamas survived the 6-week study period. Of the 6 llamas, 5 did not have signs of abdominal pain and returned to preoperative food consumption amounts within 36 hours. One llama had mild intermittent signs of abdominal pain daily for 7 days before returning to preoperative amount of food consumption. All gastrostomies leaked small amounts of gastric contents around indwelling 6- to 8-mm cannulas at the skin surface. Gastric contents did not leak when cannulas were dislodged from gastrostomy stomas. Replacement of cannulas was rapid and easy. Gravity-flow sample collection was best accomplished through 8-mm cannulas. Mean (+/- SEM) weight loss was detected in all llamas (15 +/- 3 kg) and was associated with frequent nonfeeding and stress of sample collection. Gross necropsy findings were unremarkable in 5 of 6 llamas. All mucosal tube gastrostomies were patent, and there was no evidence of peritonitis. One llama had a single fibrous adhesion connecting the operative site with the ascending colon. Histologically, small (2.5- to 15-mm diameter) partial-thickness mucosal erosions identified at the tube gastrostomy-gastric wall junctions may have been associated with indwelling gastric cannulas. The Janeway gastrostomy was generally well tolerated in the llamas and should be considered as a useful long-term fistulation technique.

Pathogenesis, prevention, and treatment of lactational insufficiency in sows

Lactational insufficiency is one of the major problems in swine production, and the consequences on the growth of the litter must be emphasized. Pathophysiology involves neuroendocrinologic interactions and the role of target organs such as the mammary glands, uterus, bladder, and gut. The complexity of these interactions and the fact that all interactions are not well understood leads to a broad approach. Some risk factors and their associations with lactational insufficiency are described to help the practitioner in the clinical approach to such a problem.

Morphometric evaluation of growth in llamas (Lama glama) from birth to maturity

Normal growth characteristics of llamas (Lama glama) were evaluated from conception until 1 week after parturition in pregnant females (study 1) and from 1 month after birth to maturity (study 2). In study 1, pregnant multiparous llamas (n = 10) were measured at monthly intervals from conception until 1 week after parturition; in study 2, llamas (n = 270) were measured once. Body weight of pregnant llamas (study 1) did not increase significantly until after the eighth month of pregnancy. Llamas of study 2 reached mature height, length, thoracic circumference, and weight at 18, 24, 36, and 36 months of age, respectively. From 1 month of age to maturity, the growth characteristics of males, nonpregnant females, and females during the first 8 months of pregnancy did not differ. Correlations (r2) between height, length, and thoracic circumference related to body weight for all but the pregnant llamas during the last 3 months of pregnancy were 0.822, 0.834, and 0.948, respectively. The equation describing thoracic circumference as a predictor of body weight was: Weight (kg) = (1.005 x 10(-3)) x circumference (cm)2.424.

Erythrocyte dyscrasia, anemia, and hypothyroidism in chronically underweight llamas

A syndrome characterized by anemia, erythrocyte dyscrasia, low body weight, and hypothyroidism was observed in 8 llamas (Lama glama). At initial examination (1 to 23 months of age; median, 7.5 months), llamas (3 males, 5 females) were markedly underweight (29 to 55 kg; median, 36 kg) and anemic (PCV, 12.9 to 25.5% [median, 19%]). Five of the llamas became progressively more anemic over time; in 2 of them, PCV decreased to less than 10%. Erythrocyte changes included severe poikilocytosis, anisocytosis, asymmetric distribution of hemoglobin within the cytoplasm, and cytoplasmic extensions from one or both poles. Six llamas had moderate to severe valgus deformities of the carpus. All llamas had low baseline serum thyroxine concentration and diminished response to thyrotropin administration. Baseline and post-thyrotropin triiodothyronine concentrations did not have consistent patterns. Five llamas were hypophosphatemic and 7 had low serum iron concentration (iron concentration was not determined in 1 llama). Orally administered iron supplementation did not induce clinical improvement. Because 3 of the affected llamas were full sisters, a genetic basis for the problem has to be considered. It was not possible to evaluate the familial relationship of the other 5 affected llamas. Although the underlying cause of the problem was not established, the prognosis for affected llamas is guarded to poor.

Role of the Ah locus in suppression of cytotoxic T lymphocyte activity by halogenated aromatic hydrocarbons (PCBs and TCDD): structure-activity relationships and effects in C57Bl/6 mice congenic at the Ah locus

Previous studies have shown that the generation of cytotoxic T lymphocytes (CTL) following allogeneic tumor challenge is suppressed in Ah-responsive C57Bl/6 mice treated with a single oral dose of the toxic, Ah receptor-binding 3,4,5,3',4',5'-hexachlorobiphenyl (HxCB). The present studies have examined the specific role of the Ah receptor in this immunotoxic response by utilizing HxCB isomers of known, varied affinity for the Ah receptor as well as by comparing effects of high-affinity Ah receptor ligands (3,4,5,3',4',5'-HxCB and 2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD]) on the CTL response of mice that differ only at the Ah locus, that is, Ah-responsive (Ahbb) and Ah-nonresponsive (Ahdd) congenic C57Bl/6 mice. Correlative changes in thymic weight, serum corticosterone (CS) levels, and spleen cellularity were also measured. The potency of HxCB congeners (3,4,5,3',4',5'-; 2,3,4,5,3',4'-; 2,4,5,2',4',5'-) and 2,3,7,8-TCDD to suppress the CTL response, to reduce spleen cellularity, to cause thymic atrophy, and to elevate serum CS levels was directly correlated with the binding affinity of the congener for the Ah receptor. Furthermore, these parameters of immunotoxicity in Ahdd C57Bl/6 mice were significantly more resistant to alterations induced by either 3,4,5,3',4',5'-HxCB or 2,3,7,8-TCDD as compared to Ahbb C57Bl/6 mice. These results strongly support an Ah receptor-dependent immunotoxic mechanism in suppression of the CTL response following acute exposure to halogenated aromatic hydrocarbons.

Endocrine changes during pregnancy, parturition and the early post-partum period in the llama (Lama glama)

Mean (+/- s.d.) pregnancy length for the 14 llamas in this study was 350 +/- 4.5 days. Plasma progesterone concentrations increased by 5 days after mating and remained elevated (greater than 2.0 ng/ml) throughout most of pregnancy. At about 2 weeks before parturition, plasma progesterone concentrations began to decline, dropped markedly during the final 24 h before parturition, and returned to basal concentrations (less than 0.5 ng/ml) by the day of parturition. The combined oestrone + oestradiol-17 beta and oestradiol-17 beta concentrations varied between 6 and 274 pg/ml and 4 and 114 pg/ml, respectively, during the first 9 months of pregnancy. Concentrations increased between 9 months after mating and the end of pregnancy with peak mean concentrations of 827 +/- 58 (s.e.m.) pg oestrone + oestradiol-17 beta/ml (range: 64-1658) and 196 +/- 10 pg oestradiol-17 beta/ml (31-294) during the last week of pregnancy. Concentrations then declined to 87 +/- 14 pg oestrone + oestradiol-17 beta/ml (7-488) and 25 +/- 5 pg oestradiol-17 beta/ml (2.5-142) during the first week post partum. Plasma cortisol concentrations varied between 2.6 and 51.9 ng/ml (14.0 +/- 0.5) from mating until 2 weeks before parturition when the concentrations began to decline. Only a slight increase in plasma cortisol concentrations was observed in association with parturition. Plasma triiodothyronine concentrations varied between 0.5 and 4.5 ng/ml (1.9 +/- 0.1) throughout pregnancy and the periparturient period.(ABSTRACT TRUNCATED AT 250 WORDS)

Growth characteristics of the llama (Lama glama) from birth to 12 months old

This study has characterised the growth patterns of the llama (Lama glama) from birth to 12 months old. Bodyweight growth was described as a function of age. As a means of predicting bodyweight, equations were developed which correlated bodyweight with specific body measurements. Regression analysis revealed a strong positive correlation of logtransformed measurements of thoracic circumference and height with bodyweight. Thoracic circumference (measured in cm) was a good predictor of bodyweight from the equation: bodyweight (kg) = (8.7 x 10(-4)) x circumference2.46 (r2 = 0.91).

Clinical reference values for serum protein electrophoresis for the llama (Lama glama)

Serum protein electrophoresis was performed on 71 clinically healthy juvenile and adult llamas (6 juvenile males, 7 juvenile females, 25 adult males, 13 adult females, and 20 pregnant females) to determine normal serum protein concentrations. Values were reported for each of the 5 groups because the groups were not homogeneous in all 8 peaks. Although the values reported here may serve as reference values for adults, they represent only a guideline for the juveniles because of the limited number of animals in each of these groups.

Evaluation of normal triiodothyronine and tetraiodothyronine concentrations in llamas (Lama glama)

Basal serum triiodothyronine (T3) and tetraiodothyronine (T4) concentrations have not been established for the llama (Lama glama). In addition, changes in T3 and T4 concentrations in response to thyroid-stimulating hormone (TSH) administration have not been determined, making clinical evaluation of problems referable to thyroid dysfunction difficult. In study 1, basal T3 and T4 concentrations were determined in serum samples collected from 132 clinically healthy llamas. The llamas were allotted to 3 groups: mature intact or neutered males (group I, n = 25), nonpregnant sexually mature females (group II, n = 21), and pregnant females (group III, n = 86). A mean concentration and a 95% confidence interval were computed for each group. An analysis of variance (ANOVA) indicated that a single confidence interval range (0.45 to 4.18, mean = 1.37 ng T3/ml) adequately defined the normal T3 concentrations for all groups. An ANOVA indicated that the T4 concentrations for the female populations (groups II and III) could be combined with a normal confidence interval range of 39 to 204 ng/ml (mean = 88 ng/ml), whereas a separate range (70 to 220 ng/ml, mean = 124 ng/ml) was determined for the male population. An ANOVA indicated that a single confidence interval range (0.0066 to 0.0321, mean = 0.0146) adequately defined the normal T3/T4 ratio for all groups. In study 2, T3 and T4 concentrations were evaluated in 10 healthy llamas immediately preceding and at 2, 4, 6, 8, and 24 hours after the IV administration of 3 IU of TSH/44 kg of body weight. The T3 and T4 concentrations were significantly higher by 2 hours after TSH administration in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Biologic characterization of canine melanoma cell lines

Eight canine melanoma cell lines were established from tissues from 6 dogs with spontaneous primary or metastatic melanomas. Cell lines were characterized for morphologic features and growth patterns on plastic, pigmentation, ultrastructure, cloning efficiency in soft agar, and tumorigenicity in nude mice. Biologic properties of cell lines were distinct and preserved during 40 to 120 passages in vitro. All cell lines were clonogenic and tumorigenic.

Pathology of Campylobacter jejuni abortion in sheep

Campylobacter jejuni was inoculated intravenously into pregnant ewes on gestation days 114 and 123 to reproduce ovine abortion. All ewes aborted 7-12 days post-inoculation. High numbers of C. jejuni were isolated from ewe tissues (caruncle, bile, cecal feces), fetal tissues, and placenta. C. jejuni colonies were identified in caruncles and placenta by light microscopy and immunoperoxidase techniques. Histologically, inoculated ewes had a severe purulent endometritis with vasculitis. Placentas from inoculated ewes and field cases showed necrosis and purulent inflammation; however, placentas from inoculated ewes had large numbers of bacterial colonies compared to few bacteria found in field cases. Histologically, only one fetus from the inoculated ewes showed lesions (purulent bronchopneumonia), whereas all fetuses from field cases had a distinct bronchopneumonia, and one fetus showed multifocal hepatic necrosis. These results suggest that C. jejuni (serotypes Penner 1 and Lior 2) is an important abortifacient organism for sheep.

Biologic properties of cell lines derived from canine mammary carcinomas

Six canine mammary tumor cell lines (5 epithelial, 1 myoepithelial) were established from dogs with spontaneous mammary carcinomas. The cells were characterized for features of morphology and growth patterns on plastic, ultrastructure, cloning efficiency in soft agar, tumorigenicity in athymic nude mice, and hormonal receptor status. Biologic properties of the cell lines were distinct and preserved during long-term culture in vitro. All cell lines were clonogenic, 5 of 6 were tumorigenic, and 3 of 5 were receptor positive for estrogen and/or progesterone.

Effect of Escherichia coli endotoxin and thyrotropin-releasing hormone on prolactin in lactating sows

Primiparous gilts were given subcutaneous injections of saline solution or 8 mg of Escherichia coli endotoxin (055:B5 strain) in saline solution on postpartum days (PPD) 2 and/or 6 and saline solution at the same site on PPD 1, 3, 5, and 7 at 1000 hours. On PPD 1 to 3 and on PPD 5 to 7, pigs were given 100 micrograms of thyrotropin-releasing hormone (TRH) IV at 1300 hours to evaluate TRH-induced prolactin (PRL) release. Blood samples were analyzed for PRL, cortisol, triiodothyronine (T3), and tetraiodothyronine (T4) concentrations. Rectal temperatures were monitored at hourly intervals between 0800 and 1500 hours on PPD 2 and 6. The PRL declined after endotoxin administration on PPD 2, but a similar decline was not seen after saline solution administration on PPD 1, 2, or 3. The PRL concentrations remained unchanged on PPD 5, 6, and 7 in gilts exposed to endotoxin for the 1st or 2nd time on PPD 6 and to saline solution on PPD 5 and 7. The TRH injection caused increases in PRL in all animals, but the PRL increase after TRH injection was significantly lower (P less than 0.05) in gilts treated with endotoxin on PPD 2. Cortisol concentrations increased after endotoxin exposure on PPD 2 and 6. Rectal temperatures increased after endotoxin exposure on PPD 2 and 6 with peak temperatures of 41.8 C and 41.6 C seen 4 and 3 hours, respectively, after endotoxin injection. The T3 and T4 response, used as an indicator of TRH perfusion of the adenohypophysis, was unchanged after endotoxin or saline solution administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Suppression of prolactin in pigs by Escherichia coli endotoxin

An endotoxin produced by Escherichia coli caused a decrease in prolactin concentrations in the plasma of sows when given at low dosages 2 days postpartum. Five to tenfold increases occurred in the plasma cortisol concentrations. Piglet growth, used as an indicator of milk secretion by the sows, was significantly depressed after the endotoxin administration. Some cases of lactation failure in the periparturient sow may thus be due to endotoxins suppressing prolactin concentrations. This appears to be the first report of a bacterial endotoxin having an effect on prolactin in any species.

Chloroplast Biogenesis: XXIV. Intrachloroplastic Localization of the Biosynthesis and Accumulation of Protoporphyrin IX, Magnesium-Protoporphyrin Monoester, and Longer Wavelength Metalloporphyrins during Greening

The intraplastidic localization of the endogenous metabolic pools from protoporphyrin to protochlorophyll was determined in Cucumis sativus. The endogenous protoporphyrin, Mg-protoporphyrin monoester + longer wavelength metalloporphyrins, protochlorophyllide and protochlorophyllide ester were membrane-bound. Protoporphyrin was synthesized in the stroma and subsequently became associated with the membranes. The membrane-associated protoporphyrin was then converted into Mg-protoporphyrin monoester + longer wavelength metalloporphyrins by membrane-bound enzymes. Although lysed plastids were capable of converting exogenous delta-aminolevulinic acid to protochlorophyllide, the net synthesis of protochlorophyllide from exogenous delta-aminolevulinic acid was lost upon segregating the lysed plastids into stromal and membrane fractions and then recombining the stromal and membrane fraction prior to incubation. The segregated membrane fraction was still capable of converting protoporphyrin into Mg-protoporphyrin monoester + longer wavelength metalloporphyrins in the presence or absence of the stromal fraction. These results indicated that although the reactions from protoporphyrin to Mg-protoporphyrin monoester and longer wavelength metalloporphyrins could survive a considerable degree of plastid disruption, the reactions from Mg-protoporphyrin monoester and longer wavelength metalloporphyrins to protochlorophyllide were more sensitive to structural disorganization.