Up-regulation of GLT1 expression increases glutamate uptake and attenuates the Huntington's disease phenotype in the R6/2 mouse.

The striatum, which processes cortical information for behavioral output, is a key target of Huntington's disease (HD), an autosomal dominant condition characterized by cognitive decline and progressive loss of motor control. Increasing evidence implicates deficient glutamate uptake caused by a down-regulation of GLT1, the primary astroglial glutamate transporter. To test this hypothesis, we administered ceftriaxone, a beta-lactam antibiotic known to elevate GLT1 expression (200 mg/kg, i.p., for 5 days), to symptomatic R6/2 mice, a widely studied transgenic model of HD. Relative to vehicle, ceftriaxone attenuated several HD behavioral signs: paw clasping and twitching were reduced, while motor flexibility, as measured in a plus maze, and open-field climbing were increased. Assessment of GLT1 expression in striatum confirmed a ceftriaxone-induced increase relative to vehicle. To determine if the change in behavior and GLT1 expression represented a change in striatal glutamate handling, separate groups of behaving mice were evaluated with no-net-flux microdialysis. Vehicle treatment revealed a glutamate uptake deficit in R6/2 mice relative to wild-type controls that was reversed by ceftriaxone. Vehicle-treated animals, however, did not differ in GLT1 expression, suggesting that the glutamate uptake deficit in R6/2 mice reflects dysfunctional rather than missing GLT1. Our results indicate that impaired glutamate uptake is a major factor underlying HD pathophysiology and symptomology. The glutamate uptake deficit, moreover, is present in symptomatic HD mice and reversal of this deficit by up-regulating the functional expression of GLT1 with ceftriaxone attenuates the HD phenotype.

A comparison of canine normal hepatic alkaline phosphatase and variant alkaline phosphatase of serum and liver.

The isoenzyme of alkaline phosphatase from normal liver, the corticosteroid induced isoenzyme of alkaline phosphatase from serum and liver and a hepatocellular variant isoenzyme of alkaline phosphatase induced by lymphosarcoma have been partially purified and their the present modification incorporates Polybrene into buffer to eliminate this heparin interference. The proposed method shown excellent agreement with a reference procedure based on clottable protein, and excellent day-to-day precision (C.V.3.5%). The present method is easily adaptable to semi-automated measurements.

Quantitative determination of equine alkaline phosphatase isoenzymes in foal and adult serum.

Automated and semiautomated assays were developed and validated for the determination of equine alkaline phosphatase isoenzymes including intestinal (IALP), bone (BALP), and liver (LALP). The addition of levamisole selectively inhibited more than 97% of LALP while inhibiting only 55% of IALP. Because these percentages were highly reproducible in an automated system, the IALP activity could be calculated in a sample. Bone alkaline phosphatase isoenzyme was selectively precipitated by adding an equal volume of wheat germ agglutinin (5 mg/mL), incubating for 30 minutes at 37 degrees C, and centrifugating. The LALP activity was determined from the supernatant fluid and BALP activity was calculated by subtraction from total ALP activity. The within-run coefficient of variation for determination of BALP activity was 4.7%. These assays were used to identify and quantify the isoenzymes present in pony foal sera through the first 21 days of life, in horse foal sera before colostrum ingestion and during the first 21 days of life, and in adult horse and pony sera. Intestinal ALP activity was not found in sera of any of the foals or adult ponies or horses. A majority of serum ALP activity of newborn foals is of bone origin (80 to 92%) which decreases markedly over the first 21 days. In adults, only 17.9% (51.2 +/- 18.1 U/L) of serum ALP is derived from bone. The absolute LALP activity in foal serum is similar to that in adults.

Safety of L-tryptophan for pigs.

Epidemic eosinophilia-myalgia syndrome (EMS) associated with excess L-tryptophan (Trp) consumption in humans has been declared a major public health problem. The EMS problem has not been observed in pigs, nor has comprehensive pathology associated with EMS in humans been described. Experiments were therefore conducted to evaluate the pathology and effects of excess dietary L-Trp for finishing (79 to 119 kg) pigs and to determine an LD50 of Trp for pigs. In Exp. 1, addition of .1 or 1% Trp to corn-soybean meal diets had no effect on growth performance or leukocyte and relative eosinophil counts or on plasma aspartate transferase, creatine phosphokinase, and lactate dehydrogenase activities. Likewise, untoward pathological effects of Trp feeding were not observed in the animals under study. In Exp. 2, supplementing the basal diet with 0, 2, and 4% Trp caused linear (P less than .05) decreases in weight gain, feed intake, and gain:feed ratio. Mortality could not be produced by acute oral dosing in the LD50 study (Exp. 3), wherein Trp doses between 2.00 and 5.71 g/kg of BW were administered by stomach tube. Vomiting occurred at oral doses greater than 5.71 g/kg of BW. These results suggest that oral ingestion of Trp in pigs is safe and that pigs can tolerate considerable excesses of Trp.

Disappearance rates of intravenously injected canine alkaline phosphatase isoenzymes.

The serum half-life of various canine alkaline phosphatase isoenzymes has been determined. Isoenzymes can be divided into 2 groups with regard to their half-life. Isoenzymes with a half-life of approximately 3 days include the hepatic alkaline phosphatase and the steroid-induced alkaline phosphatase. Those with a half-life of under 6 minutes include the alkaline phosphatase from placenta, kidney, intestine, and the hepatic and steroid-induced iosenzymes after removal of sialic acid. The inability to demonstrate some of the isoenzymes of alkaline phosphatase in serum of diseases animals is attributed to their short half-life. The relationship of the short half-life to the sialic acid moiety of the protein is discussed.

Serum half-life of intravenously injected intestinal and hepatic alkaline phosphatase isoenzymes in the cat.

The serum half-life of feline intestinal alkaline phosphatase (ALP) in the cat was 2 minutes, and that of feline hepatic ALP, 5.8 hours. The feline hepatic ALP could not be identified in the urine of the cats, nor was the clearance rate affected by bilateral nephrectomy. These data indicated the shor serum half-life of hepatic ALP was not a reusult of renal excretion. Since canine hepatic ALP cleared from feline blood at the same rate as the feline hepatic ALP, possibly the discrepancy in hepatic ALP half-life between the species was related to the cats' ability to clear the blood of the enzyme.

Normal canine lipid profiles and effects of experimentally induced pancreatitis and hepatic necrosis on lipids.

Normal lipid profiles (total lipids, total cholesterol, phospholipids, free fatty acids, triglycerides, and lipoproteins) were determined in 23 clinic-reared dogs and 26 client-owned dogs. A significantly higher concentration of cholesterol was found in client-owned dogs as compared with clinic-reared dogs. Hepatic necorosis, induced by CCl4, resulted only in a significant decrease in triglycerides. Acute pancreatitis, induced by major and minor pancreatic duct ligations, resulted in a significant increase in free fatty acids and low-density lipoprotein with a decrease in high-density lipoprotein-2.

Alterations in selected serum biochemical constituents in equids after induced hepatic disease.

Effects of induced cholestasis and hepatocellular necrosis and of fasting on serum biochemical constituents including bile acids, IgA, bilirubin, alkaline phosphatase, gamma-glutamyltransferase (GGT), arginase, and the clearance of sodium sulfobromophthalein were studied in 4 groups of equids. The reference value for serum bile acids, as determined by an enzymatic colorimetric procedure for horses and ponies was 5.94 +/- 2.72 mumol/L, there being no statistical difference for horses and ponies. Sample collection at time of feeding had no effect on serum bile acid concentration. Seemingly, serum bile acids, arginase, and GGT were the most sensitive indicators of cholestasis and/or hepatocellular necrosis and would form an essential minimum effective battery of tests to diagnose and prognose hepatic disease in equids. These tests provided a measure of hepatobiliary transport function (bile acids), cell necrosis (arginase), and cholestasis (GGT and bile acids).

Purification and comparison of corticosteroid-induced and intestinal isoenzymes of alkaline phosphatase in dogs.

Corticosteroid-induced alkaline phosphatase (CALP) and intestinal alkaline phosphatase (IALP) from dogs were purified to homogeneity, as determined by polyacrylamide gel electrophoresis. Purification involved an un-interrupted system using DEAE-cellulose, concanavalin A-agarose, and monoclonal antibody affinity columns. The monoclonal antibody was prepared by use of IALP as the antigen. The 2 isoenzymes were compared, using molecular weight determinations, amino acid analyses, peptide mapping, N-terminal sequencing of the first 10 amino acids, carbohydrate analyses, and recognition by anti-IALP monoclonal antibody. The data indicated that canine IALP and CALP are identical with regard to recognition by monoclonal antibody and N-terminal amino acid sequence, nearly identical in amino acid content and peptide maps, but different in carbohydrate content. It was concluded that CALP is a product of the same gene as IALP and that differences in glycosyl transferase activities between liver and intestines or the presence of glycosidase activities in or around the intestinal mucosae result in the marked difference in carbohydrate content.

Effects of sewage sludge-fertilized corn fed to growing swine.

Swine (2 groups) fed a ration containing 79% corn from sewage sludge-fertilized plots for 8 weeks may have had a modest performance advantage over swine fed corn from plots heavily fertilized with commercial nitrogen. Sludge-fertilized corn feeding-related deviations from population normals for electroencephalograms, electrocardiograms, clinical chemistry, or histopathology were not observed; however, swine fed sludge-fertilized corn differed significantly from the control swine for certain physiologic and biological characteristics, indicating possible interference with glucose metabolism and microsomal mixed-function oxidase activity. Control swine had mild microcytic anemia associated with parasitism, but swine in the principal groups were less adversely affected, probably due to higher iron intake. Corn heavily fertilized with sewage sludge from an urban-industrial complex can be safely fed to swine, based on these results, but it might be advantageous to feed on a short-term or intermittent schedule. Residues of heavy metals in the animal products must be examined.

Immunoassay for the steroid-induced isoenzyme of alkaline phosphatase in the dog.

Antiserum directed against the steroid-induced alkaline phosphatase (ALP) isoenzyme of the dog was produced in rabbits. This antiserum was used to develop a sensitive and quantitative assay for the detection of the steroid-induced ALP isoenzyme in the serum of dogs. This antiserum was also used to enhance the electrophoretic separation of the steroid-induced and hepatic ALP isoenzymes.

Comparison of the steroid-induced, intestinal, and hepatic isoenzymes of alkaline phosphatase in the dog.

The steroid-induced, intestinal, and hepatic isoenzymes of canine alkaline phosphatase (ALP) were compared, using antibodies against the steroid-induced ALP isoenzyme, heat inactivation, phenylalanine inhibition, prednisolone inhibition, and Michaelis constant determinations. The results indicate that the steroid-induced and intestinal ALP isoenzymes are similar and indicate that the steroid-induced isoenzyme might be a product of the same gene that controls the intestinal isoenzyme.

Haptoglobin and ceruloplasmin as determinants of inflammation in dogs.

Assay procedures for determining serum haptoglobin concentration and ceruloplasmin oxidase activity in dogs were validated, and reference values were established. Serum haptoglobin concentration is reported as milligrams per deciliter of cyanmethemoglobin binding capacity, whereas serum ceruloplasmin oxidase activity was determined by use of p-phenylenediamine as substrate. Both assays were used to analyze serum samples from 288 dogs. In each dog's case record, clinical history and final diagnosis were evaluated to determine whether the dog had an inflammatory condition. Complete blood cell counts were performed in 265 dogs, using simultaneously collected blood samples. Plasma fibrinogen concentration was determined for 161 dogs. A positive correlation (P less than 0.01) for serum haptoglobin concentration and for ceruloplasmin oxidase activity, compared with WBC counts, segmented neutrophil and band neutrophil counts, and plasma fibrinogen concentration. Ceruloplasmin oxidase activity and haptoglobin concentration were up to 6 times more sensitive than fibrinogen concentration or leukocyte counts in detecting inflammation. Specificity of ceruloplasmin oxidase activity was comparable to fibrinogen concentration and leukocyte counts, whereas haptoglobin concentration was found to be slightly less specific. Specificity of haptoglobin concentration improved slightly (from 0.82 to 0.88) when dogs with a history of glucocorticoid administration were excluded from analysis. Predictive value of a negative test result (haptoglobin concentration less than 125 mg/dl; ceruloplasmin oxidase activity less than 20 IU/L) and predictive value of a positive test result for haptoglobin concentration and ceruloplasmin activity were comparable to or better than fibrinogen concentration or various oxidase leukocyte counts in detection of inflammation in a variety of disease conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of corticosteroid-induced alkaline phosphatase isoenzyme as a screening test for hyperadrenocorticism in dogs.

Quantitative determination of the corticosteroid-induced isoenzyme of alkaline phosphatase (CAP) was evaluated as a screening test for hyperadrenocorticism (HAC) in dogs. A series of 40 dogs with HAC (CAP range, 96 to 14,872 U/L), 30 clinically normal dogs (CAP range, 0 to 38 U/L), and 80 dogs with various diseases (non-HAC) and without history of exogenous glucocorticoid exposure for a minimum of 60 days (CAP range, 0 to 1163 U/L) were used to evaluate the test. Sensitivity and specificity of CAP was calculated at various cutoff points for absolute CAP activity and for CAP activity expressed as a percentage of total alkaline phosphatase activity. A cutoff point of 90 U/L was selected as optimal for use of this assay as a screening test for HAC. A prevalence survey then was done of all canine serum samples submitted to our diagnostic laboratory over a 3-month period, to calculate the predictive values of a positive and a negative test result in a clinical population and to determine the relative frequency and magnitude of CAP activity in dogs that had received glucocorticoids. The predictive values of a positive and a negative test result at the 90 U/L cutoff value were 21.43% (95% confidence limits, 8.3 to 40.95%) and 100% (95% confidence limit > 96%), respectively. It was concluded that CAP isoenzyme activity, determined by routine biochemical analysis by an automated levamisole-inhibition assay, could function as a screening test for HAC; however, the predictive value of a positive test result was too low to recommend the assay as a diagnostic test.(ABSTRACT TRUNCATED AT 250 WORDS)

Disseminated meningeal tumor in a dog.

A 6-year-old Golden Retriever was referred for evaluation of hind limb paresis and generalized weakness. Neurologic examination revealed multifocal cervical and lumbosacral spinal disease. Radiography and myelography failed to identify a lesion. Cerebrospinal fluid was markedly cellular and had a high protein concentration, consistent with myelitis or a neoplastic process. The dog did not improve with medical management. Gross and histologic examination of the brain and spinal cord revealed a thick meningeal surface characterized by polymorphic histiocytic-like cells to multinucleate giant cells. The neoplastic process was considered to be a disseminated meningeal polymorphic cell sarcoma.

An electronic approach to evaluating healthcare Web resources.

Information literacy skills, which include the ability to evaluate electronic healthcare sites, are critical to the decision-making responsibilities of students and professionals. The authors describe the experiences of nursing and library services faculty in the development and implementation of a Web-delivered module for the evaluation of healthcare Web resources. A range of electronic tools was used for both the collaborative creation of the module as well as the instructional delivery of the content. Evaluation of the module revealed its usefulness to the students and the potential of the collaborative development model for other content areas.