Adrenomedullin (AM) and adrenomedullin binding protein (AM-BP) in the bovine mammary gland and milk: Effects of stage of lactation and experimental intramammary E. coli infection     

Elsasser TH  Capuco AV  Caperna TJ  Martínez A  Cuttitta F  Kahl S 《Domestic animal endocrinology》2007,32(2):138-154

Adrenomedullin (AM) has been characterized as an endogenous tissue survival factor and modulator of many inflammatory processes. Because of the increased susceptibility of the mammary gland to infection during the time surrounding parturition in the cow, we investigated how milk and tissue content of AM and its binding protein (AM-BP) might be affected by the stage of lactation and the udder health status. Milk and mammary biopsy samples were obtained from Holstein cows 21 days prior to and at various times after calving to represent the dry period and early and mid-stages of lactation. Additional cows received an intramammary challenge with Escherichia coli for immunohistochemical characterization of AM and AM-BP. Milk AM concentrations were relatively constant across the stages of lactation while AM-BP increased two-fold (P<0.04) between early and mid-lactation. Milk AM (P<0.04) and AM-BP (P<0.03) increased as somatic cell counts (SCCs) increased within a given stage of lactation. Tissue content of both (AM and AM-BP) were significantly affected by stage of lactation, lowest in the dry period and progressively increasing to peak at mid-lactation as well as increasing in association with higher levels of SCCs. Following E. coli challenge, AM increased in epithelial cells surrounding mammary alveoli presenting high levels of SCCs. The data suggest that AM and AM-BP are cooperatively regulated in the mammary gland during lactation; changes in localized tissue AM and AM-BP content reflect a dynamic regulation of these tissue factors in the bovine mammary gland consistent with their protective effects within inflamed tissue.  相似文献   

Lactation persistency: insights from mammary cell proliferation studies   总被引：1，自引：0，他引：1  

Capuco AV  Ellis SE  Hale SA  Long E  Erdman RA  Zhao X  Paape MJ 《Journal of animal science》2003,81(Z3):18-31

A persistent lactation is dependent on maintaining the number and activity of milk secreting cells with advancing lactation. When dairy cows are milked twice daily, the increase in milk yield from parturition to peak lactation is due to increased secretory activity per cell rather than to accretion of additional epithelial cells. After peak lactation, declining milk yield is due to loss of mammary epithelial cells by apoptosis. During lactation, only 0.3% of mammary cells proliferate in a 24-h period. Yet this proliferative rate is sufficient to replace most mammary epithelial cells by the end of lactation. Management practices can influence lactation persistency. Administration of bovine somatotropin may enhance persistency by increasing cell proliferation and turnover, or by reducing the rate of apoptosis. Increased photoperiod may also increase persistency of lactation by mechanisms that are as yet undefined. Increased milking frequency during the first weeks of lactation increases milk yield, even after return to less frequent milking, with increases of approximately 8% over the entire lactation. A mammary cell proliferation response to frequent milking during early lactation appears to be involved. Conversely, advanced pregnancy, infrequent milking, and mastitis increase death of epithelial cells by apoptosis. Regulation of mammary cell renewal provides a key to increasing persistency. Investigations to characterize epithelial cells that serve as the proliferative population in the bovine mammary gland have been initiated. Epithelial cells that stain lightly in histological sections are evident through all phases of mammary development and secretion and account for nearly all proliferation in the prepubertal gland. Characterization of these cells may provide a means to regulate mammary cell proliferation and thus to enhance persistency, reduce the effects of mastitis, and decrease the necessity for a dry period.  相似文献   

Evaluation of L-selectin expression and assessment of protein tyrosine phosphorylation in bovine polymorphonuclear neutrophil leukocytes around parturition   总被引：3，自引：0，他引：3  

Monfardini E  Paape MJ  Wang Y  Capuco AV  Husheem M  Wood L  Burvenich C 《Veterinary research》2002,33(3):271-281

Impaired polymorphonuclear neutrophil leukocyte (PMN) function around parturition has been associated with increased clinical mastitis in dairy cows. Rolling and attachment of PMN to the endothelium is the first step in the recruitment process and is accomplished by interaction between L-selectin on PMN and its ligand on endothelial cells. Furthermore, tyrosine phosphorylation is involved in the initiation of many PMN functions. The objective of this work was to determine changes in expression of L-selectin and tyrosine phosphorylation in the perinatal period. Eight clinically healthy Holstein cows were used as PMN donors at d-21, -14, -7,0 (calving), +1, +2, +7, +14, +28. Evaluation of L-selectin expression was carried out on activated and resting PMN. Anti-bovine L-selectin monoclonal antibody (MAB) and flow cytometric analysis were used to measure the percentage of PMN fluorescing and receptor expression (log mean fluorescent channel, LMFC). Activated and resting PMN showed similar trends in % PMN fluorescence and LM FC. The percentage of PMN fluorescing tended to decrease at parturition, followed by a significant increase at d +14 and +28 (P < 0.02). For LMFC a decrease was observed on d +1 followed by an increase through d +28 (P < 0.01). Protein tyrosine phosphorylation of lysates prepared from PMN isolated throughout the study was detected by electrophoresis and western blotting using anti-phosphotyrosine MAB. Several protein bands were tyrosine phosphorylated. Two of these bands (42-44 kDa and 90 kDa) varied in intensity over time. The intensity of the 42-44 kDa band gradually increased from d -7, peaked at d +7 (P < 0.03), and steadily decreased to d +28 (P < 0.02). Antibody to activated mitogen protein kinase reacted with the 42-44 kDa band. Reduced PMN function during the periparturient period could be related to reduced L-selectin adhesion molecules on the cell surface, and to modulation in the phosphorylation of functionally important molecules.  相似文献   

Effects of cross-tying horses during 24 h of road transport     

Stull CL  Rodiek AV 《Equine veterinary journal》2002,34(6):550-555

Transportation stress has been implicated as a predisposing factor to respiratory disease in horses. Cross-tying horses individually in stalls is common practice for transporting show and racehorses, but horses also travel in small groups or individually without being restricted by tying. The objective of this study was to compare physiological responses of horses travelling cross-tied or loose during 24 h of road transport. Ten horses were used in a cross-over design consisting of two 4 day trials. In the first trial, 6 horses were cross-tied, while 2 pairs of horses were loose in enclosed compartments. Treatments were reversed in the second trial. Baseline samples were collected on Day 1, horses transported on Day 2, and recovery data collected on Days 3 and 4. Blood samples were collected daily at 0800, 1100 and 2000 h. The mean responses in all horses of serum cortisol, lactate, glucose, alpha1-acid glycoprotein, and total protein concentrations, packed cell volume (PCV), white blood cell (WBC) counts and aminotransferase and creatine kinase were was elevated significantly from baseline during the 4 day study. The response of white blood cell counts, neutrophil to lymphocyte ratios and glucose and cortisol concentrations was significantly elevated in the cross-tied compared to the loose group during transport and recovery. This study supports the recommendation of allowing horses during long-term transportation to travel loose in small compartments, without elevating their head by cross-tying.  相似文献   

SOUTHWESTERN ARCHEOLOGICAL CONFERENCE     

Kidder AV 《Science (New York, N.Y.)》1927,66(1716):489-491

  相似文献   

The biochemistry of muscle training     

PALLADIN AV 《Science (New York, N.Y.)》1945,102(2658):576-578

  相似文献   

Effect of accelerated autolysis of yeast on the composition and foaming properties of sparkling wines elaborated by a champenoise method     

Nunez YP  Carrascosa AV  González R  Polo MC  Martínez-Rodríguez AJ 《Journal of agricultural and food chemistry》2005,53(18):7232-7237

Five mutants (obtained by UV mutagenesis) and the parent strain were selected to produce sparkling wines following the traditional or champenoise method. The wines were aged with the yeast for 9 months, with samples being taken each month for analytical and sensory determinations. The wines elaborated with mutant strain IFI473I demonstrated an accelerated release of protein, amino acids, and polysaccharides. An analysis of the secreted polysaccharides revealed that mannose was the major sugar present. The effects of the products released by yeasts on the foaming properties of the wines were determined by both sensory and instrumental analysis. In all cases, the wines elaborated with mutant strain IFI473I showed improved foaming properties as compared to wines fermented without this strain. Similar results were obtained at a decreased aging time of 6 months, thereby confirming the capacity of IFI473I strain to carry out an accelerated autolysis. These results demonstrate that mutant strain IFI473I can significantly reduce production times of high-quality sparkling wines.  相似文献   

Software and the future of programming languages     

Aho AV 《Science (New York, N.Y.)》2004,303(5662):1331-1333

Although software is the key enabler of the global information infrastructure, the amount and extent of software in use in the world today are not widely understood, nor are the programming languages and paradigms that have been used to create the software. The vast size of the embedded base of existing software and the increasing costs of software maintenance, poor security, and limited functionality are posing significant challenges for the software R&D community.  相似文献   

Flora north america     

Hall AV 《Science (New York, N.Y.)》1973,182(4113):652

  相似文献   

Characterization of mammalian selenoproteomes   总被引：3，自引：0，他引：3  

Kryukov GV  Castellano S  Novoselov SV  Lobanov AV  Zehtab O  Guigó R  Gladyshev VN 《Science (New York, N.Y.)》2003,300(5624):1439-1443

In the genetic code, UGA serves as a stop signal and a selenocysteine codon, but no computational methods for identifying its coding function are available. Consequently, most selenoprotein genes are misannotated. We identified selenoprotein genes in sequenced mammalian genomes by methods that rely on identification of selenocysteine insertion RNA structures, the coding potential of UGA codons, and the presence of cysteine-containing homologs. The human selenoproteome consists of 25 selenoproteins.  相似文献