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Biomedical subjects

A E Larsen

Publications and source records attributed to A E Larsen.

At least 19 recordsLinked to original sources
PubMed2006

Actions of short-term fasting on human skeletal muscle myogenic and atrogenic gene expression.

BACKGROUND: Skeletal muscle mass is governed by multiple IGF-1-sensitive positive regulators of muscle-specific protein synthesis (myogenic regulatory factors which includes myoD, myogenin and Myf5) and negative regulators, including the atrogenic proteins myostatin, atrogin-1 and muscle ring finger 1 (MuRF-1). The coordinated control of these myogenic and atrogenic factors in human skeletal muscle following short-term fasting is currently unknown. METHOD: Healthy adults (n = 6, age 27.6 years) undertook a 40-hour fast. Skeletal muscle biopsy (vastus lateralis) and venous blood samples were taken 3, 15 and 40 h into the fast after an initial standard high-carbohydrate meal. Gene expression of the myogenic regulator factors (myoD, myogenin and Myf5) and the atrogenic factors (myostatin, atrogin-1 and MuRF-1) were determined by real-time PCR analysis. Plasma myostatin and IGF-1 were determined by ELISA. RESULTS: There were no significant alterations in either the positive or negative regulators of muscle mass at either 15 or 40 h, when compared to gene expression measured 3 h after a meal. Similarly, plasma myostatin and IGF-1 were also unaltered at these times. CONCLUSIONS: Unlike previous observations in catabolic and cachexic diseased states, short-term fasting (40 h) fails to elicit marked alteration of the genes regulating both muscle-specific protein synthesis or atrophy. Greater periods of fasting may be required to initiate coordinated inhibition of myogenic and atrogenic gene expression.

Adult↗
PubMed1994

Hepatic plasmacytoma and biclonal gammopathy in a cat.

A 13-year-old castrated male domestic shorthair cat was evaluated because of weight loss, despite a good appetite. The most remarkable abnormality was a total serum protein concentration of 12.4 g/dl, with a globulin concentration of 9.4 g/dl. Serum protein electrophoresis revealed a biclonal spike in the gamma region. At necropsy, 2 discrete plasmacytomas were found in the liver, without bone marrow involvement or amyloidosis.

Animals↗
PubMed1990

Monitoring therapy with LMW heparin: a comparison of three chromogenic substrate assays and the Heptest clotting assay.

Three LMW heparins (LMWH), one unfractionated heparin (UH), and international standards of LMWH and UH were compared in three chromogenic substrate (CS) assays and the 'Heptest' clotting assay. With a two-stage CS assay, linear standard curves were obtained in the 0.1-1.0 U/ml range, nearly coinciding for all preparations. With the one-stage CS assays, standard curves were curvilinear and similar for UH and the LMWH groups. In the Heptest assay, standard curves were linear for UH but not for LMWH. Mean recovery of LMWH, added to patients' plasma samples was 70-98% for the four assays. Variation between individual recoveries was much greater with Heptest (coefficient of variation (CV) 35-44%) than with one-stage CS assays (CV 14-21%) or two-stage CS assays (CV 7-8%). For monitoring LMW heparin therapy, CS assays seem preferable to Heptest. The two-stage CS assay had superior accuracy, but the one-stage CS assays were easier to perform.

Automation↗
PubMed1989

Pulpal response to irradiation of enamel with continuous wave CO2 laser.

Selected dog's teeth, in vivo, were exposed to carbon dioxide (CO2) laser power densities ranging from 13 to 102 J per cm2. The teeth were extracted 48 h postlasing, fixed with 10% neutral buffered formalin, decalcified with Kristensen's solution, processed, sectioned, stained, and evaluated for pulpal damage. No pulpal damage was observed when compared with nonlased control teeth. It appears that carbon dioxide laser power densities of approximately 13 to 102 J per cm2 could be used to irradiate enamel of teeth without damage to the pulp.

Animals↗
PubMed1989

Evaluation of canine mast cell tumors for presence of estrogen receptors.

Ten tumors from 7 dogs were analyzed for estrogen receptors. Of 9 determined to be mast cell tumors, 6 were determined not to have estrogen receptors (less than 3 fmol of estradiol/mg of cytosol protein) and 3 were questionable (3 to 10 fmol of estradiol/mg). One tumor was a mixed mammary tumor and was determined to have estrogen receptors (12 fmol of estradiol/mg). Histologic grading of the mast cell tumors did not suggest a correlation with estrogen receptor values.

Animals↗
PubMed1987

Graft versus host disease following transfusion of normal blood products to patients with malignancies.

A patient undergoing treatment with cytotoxic chemotherapy for Hodgkin's disease developed graft versus host disease (GVHD) following a transfusion of packed red cells. This is the 28th reported patient with a malignancy who did not have a bone marrow transplant and developed GVHD after transfusion of normal blood or blood products. All patients had received cytotoxic chemotherapy prior to acquiring GVHD. The underlying malignancies included lymphoma, acute leukemia, neuroblastoma, rhabdomyosarcoma, and glioblastoma. Twenty-three of the 28 patients died of GVHD. The incidence of transfusion-related GVHD in this patient population is low but the illness is often fatal as treatment is largely ineffective. Transfusion-related GVHD can be prevented by irradiating all blood products with 1500 rad prior to administration.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1987

Restricted viral antibody specificity in many ferrets infected with the ferret Aleutian disease parvovirus. Brief report.

The majority of ferrets infected with a ferret strain of Aleutian disease virus (ADV) produce antibody only to a detergent-sensitive common determinant on the two closely related virion proteins. Ferrets with high antibody titers and mink infected with this virus also produce antibody to one or more virion immunogenic determinants unaffected by detergent.

Aleutian Mink Disease↗
PubMed1987

Effects of diets containing sodium fluoride on mink.

Mink (Mustela vison) kits still nursing, and adult male mink were fed diets containing various levels of fluorine (as NaF) to determine the effects on health, growth and pelt quality. Different groups were fed diets containing 25.5 (control), 46.0, 111.5 or 287.0 ppm fluorine (on a wet basis) for 7-8 mo. Gross, radiographic and microscopic changes were seen in bones from some animals ingesting the higher levels of fluorine. Chemical analyses for fluorine generally reflected levels ingested. Fluorine caused no detectable differences in pelt quality. After data were evaluated, tolerance levels in the feed of not more than 50 ppm fluorine for breeding stock and 100 ppm fluorine for animals being raised only for pelts are recommended.

Animals↗
PubMed1984

Immunoglobulin classes of Aleutian disease virus antibody.

Aleutian disease virus (ADV) persistently infects mink and causes marked hypergammaglobulinemia. Immunoglobulin class-specific antisera were used to define the total immunoglobulin of each class by radial immunodiffusion and the immunoglobulin class of ADV-specific antibody by immunofluorescence in experimentally and naturally infected mink. Electrophoretic gamma globulin closely reflects the immunoglobulin G (IgG) level in mink, and the majority of the increased immunoglobulin and ADV antibody in infected mink is IgG. IgM becomes elevated within 6 days after infection, reaches peak levels by 15 to 18 days, and returns to normal by 60 days after infection. The first ADV antibody demonstrable is IgM, and most mink have virus-specific IgM antibody for at least 85 days postinfection. Serum IgA levels in normal mink are not normally distributed, and ADV infection causes a marked elevation of IgA. Low levels of ADV-specific IgA antibody can be shown throughout the course of infection. Failure of large amounts of virus-specific IgG antibody to inhibit the reaction of virus-specific IgM and IgA antibodies suggests that the various classes of antibodies are directed against spatially different antigenic determinants. The IgM and IgA were shown not to be rheumatoid factors.

Aleutian Mink Disease↗
PubMed1984

Immunoenzyme Western blotting analysis of antibody specificity in Aleutian disease of mink, a parvovirus infection.

Aleutian disease virus (ADV), an autonomous parvovirus, persistently infects mink and induces very high levels of virus-specific antibody. All strains of ADV infect all mink, but only highly virulent strains cause progressive disease in non-Aleutian mink. The development of antibody to individual ADV proteins was evaluated by Western blotting by using the sera of 22 uninfected mink and 163 naturally or experimentally infected mink. ADV has virion proteins of 86,000 and 78,000 daltons that are closely related. A new, possibly nonvirion protein of 143,000 daltons was observed, as well as a known nonvirion protein of 71,000 daltons. Sera from mink experimentally or naturally infected with ADV of high or low virulence generally reacted about equally with all four proteins. The only exceptions noted were that 8 of 15 sera of mink infected transplacentally preferentially reacted with the two virion proteins and sera from mink with the monoclonal gammopathy of Aleutian disease reacted preferentially with either virion (10 of 12) or nonvirion (2 of 12) proteins.

Animals↗
PubMed1984

Much of the increased IgG in Aleutian disease of mink is viral antibody.

Aleutian disease (AD) is caused by a persistent infection of mink with an autonomous parvovirus. Chronically infected mink develop widespread plasmacytosis, a marked elevation of their serum IgG, and immune complex disease. A substantial fraction of the IgG in the serum of mink with Aleutian disease may be specifically absorbed by monolayer cell cultures infected with Aleutian disease virus. The maximum percentage of absorption of IgG found was 81% in a mink with 5.4 g/dl of IgG. Mink with the monoclonal gammopathy of Aleutian disease had a particularly large percentage of the IgG absorbed. The percentage of IgG absorbed from serums of mink with Aleutian disease is directly proportional to the serum IgG level and to the Aleutian disease viral antibody titer. The amount of IgG which can be absorbed by infected cell monolayers increases during the course of experimental infection, and the absorption is immunologically specific. Thus, it appears that much of the hypergammaglobulinemia in mink with Aleutian disease represents virus-specific antibody.

Aleutian Mink Disease↗
PubMed1982

HbA1 determination by agar gel electrophoresis after elimination of labile HbA1: a comparison with ion-exchange chromatography.

A rapid and simple method, Agar gel electrophoresis (GlytracTM, Corning Medical), for HbA1 analysis was evaluated and compared with an ion-exchange chromatography method capable of estimating HbA1 (a+b) and HbA1c separately. Preincubated samples from diabetics and normals were analysed by both methods and showed good correlation (r=0.97, n=89). The following data were obtained with agar gel electrophoresis. Incubation of erythrocytes at a glucose concentration of 30 mmol/l for 6 h at 37 degrees C gave an increase of 1.39% HbA1. This increase was almost reversed by reincubation in low glucose medium. By preincubation of erythrocytes in saline HbA1 decreased 0.90 +/- 0.39% HbA1 (mean +/- SD) in diabetics and 0.38 +/- 0.26% HbA1 in normal controls. This preincubation step is necessary to eliminate the labile HbA1 fraction when HbA1 is to be used as an index of long term glucose control in diabetes. The HbA1 ranged from 5.1 to 7.4% (n=68), mean 5.8% (SD 0.5). HbA1 in patients with juvenile diabetes ranged from 6.1 to 19.3%. Within-run precision (CV) was 2.3 and 2.5% in normal and diabetic samples, respectively. Between-run precision was 5.7%. Variation in temperature between 18.5 and 31.5 degrees C did not affect the HbA1 values significantly. Within-run and between-run precision for chromatography was 3.4 and 4.7% respectively. Agar gel electrophoresis is a simple and rapid method for HbA1 determination, with acceptable precision and accuracy.

Blood Glucose↗
PubMed1982

Aleutian disease in ferrets.

When 32 antibody-free ferrets were inoculated with the highly mink-virulent Utah-1 strain of Aleutian disease virus (ADV), most developed ADV antibody starting 15 days after infection, but the antibody titers were much lower than those seen in mink. Relatively small amounts of ADV were demonstrated in CRFK cell culture, using ferret spleen and lymph node homogenates only 4 to 10 days after experimental infection, but low-level viral persistence for 180 days was shown by mink inoculation. The ferrets inoculated with the Utah-1 strain of ADV did not develop elevated gamma globulin levels, but did have mild tissue lesions. Forty-two percent of a group of 214, approximately 1-year-old, recently pregnant, female ferrets were found to have antibody to ADV. An analysis of the serum proteins of the ferrets with ADV antibody showed that they had a significant, but mild, elevation of their serum gamma globulin. Serial ferret-to-ferret transmission of a ferret strain of ADV by inoculation of spleen homogenates was demonstrated, and some of these ferrets developed liver lesions. Mink inoculated with ferret ADV made antibody, but did not develop hypergammaglobulinemia or tissue lesions. Although both ferret and mink strains of ADV replicate and persist in the ferret, they fail to cause severe disease of the type usually seen in the closely related mink. Mink and ferret ADV strains appear to be biologically distinct.

Aleutian Mink Disease↗
PubMed1982

Identification of T lymphocytes by a histochemical stain for alpha naphthyl acetate esterase activity.

Lymphocyte suspensions and peripheral blood smears from 20 normal individuals were examined for nonspecific esterase activity, using alpha naphthyl acetate as substrate and hexazotized pararosanilin stain. Lymphocytes show intense, focal, red "dot-like" activity; monocytes show diffuse reddish granulation. B lymphocytes do not react. Critical variables of the procedure include: use of proper anticoagulant; fixation for 30-180 seconds; incubation with substrate 3-5 hours; and pH 5.8. Comparison of results with conventional E rosette methodology showed 53-63% rosettes; 50-58% esterase-positive lymphocytes in cytocentrifuge preparations and 47-59% esterase-positive lymphocytes on peripheral blood films. Technical advantages of the procedure favor it as an alternative method for assessing T lymphocytes.

Esterases↗
PubMed1979

Porcine nephropathy induced by long-term ingestion of ochratoxin A.

Nine pigs were fed crystalline ochratoxin A in their feed at a concentration of about 1 mg/kg. Three pigs and their controls were killed after 3 months and 6 pigs and controls were killed after 2 years. A decrease of the ratio TmPAH/CIn, increased urinary glucose excretion and decreased ability to concentrate urine, occurred within a few weeks and aggravated slightly during the 2-year period. Changes in renal structure, characterized by degeneration and atrophy of proximal tubules, interstitial fibrosis and hyalinization of glomeruli, were progressive during time of exposure, but terminal renal failure was not reached. The kidney, liver, muscular and adipose tissue contained 3 to 27 microgram ochratoxin A/kg after 3 months of exposure. No further accumulation of ochratoxin A residue was found after 2 years of exposure.

Animals↗