Cell death and CD14 expression in resident and inflammatory polymorphonuclear leukocytes from virgin bovine mammary gland.

This paper investigates the association between expression of CD14 and occurrence of apoptosis in blood, resident ((RES)PMN) and inflammatory ((INF)PMN) polymorphonuclear leukocytes (PMN) from heifer mammary glands. The fresh population of (RES)PMN contained a statistically significant higher proportion of CD14+, apoptotic and necrotic cells than did populations of (INF)PMN and blood PMN. In vitro cultivation of (RES)PMN, (INF)PMN and blood PMN led to concurrent increase of apoptotic, necrotic and CD14+ cells.

Apoptosis of resident and inflammatory macrophages before and during the inflammatory response of the virgin bovine mammary gland.

Background: Macrophages may play a prominent role in defense of the bovine mammary gland, and their functionality is necessary for successful eradication of bacterial pathogens. In contrast to necrosis, however, apoptosis has not yet been studied in macrophages from bovine mammary glands. Therefore, the aim of this study was to confirm the occurrence of apoptosis in macrophages from resting heifer mammary glands and during the inflammatory response.

Effect of Staphylococcus aureus and Streptococcus uberis on apoptosis of bovine mammary gland lymphocytes.

The aim of this study was to determine whether lymphocyte apoptosis is modulated by infections caused by Staphylococcus aureus and Streptococcus uberis. Samples of cell populations were obtained by lavage of the mammary glands at 4 intervals (24, 48, 72 and 168 h) following infection. The percentage of apoptotic lymphocytes peaked at 168 h after challenge with S.

Monitoring major mastitis pathogens at the population level based on examination of bulk tank milk samples.

The objective was to determine the proportions and bacterial counts of major mastitis pathogens in samples of bulk tank milk (BTM), as well as to clarify the relationship between these bacteria counts and bulk tank somatic cell count (BTSCC). The purpose was to judge the importance of the counts of mammary pathogens for BTSCC at the population level. Samples of BTM were collected from 268 randomly selected anonymous dairy herds (with approximately 29 000 dairy cows).

Expression of macrophage CD44 receptor in the course of experimental inflammatory response of bovine mammary gland induced by lipopolysaccharide and muramyl dipeptide.

The aim of this study was to investigate development over time of the surface expression of CD44 on macrophages during an inflammatory response of bovine mammary gland. Intramammary instillation of muramyl dipeptide (MDP) and lipopolysaccharide (LPS) resulted in a significant increase in the total count of CD44+ non-vacuolised macrophages ((N)MAC) after 24h. During resolution of the inflammatory response, there was observed a gradual decrease in the total count CD44+ (N)MAC.

Bulk tank milk somatic cell count as an indicator of the hygiene status of primary milk production.

The objective was to clarify the association between bulk tank milk somatic cell count (BTSCC) and total bacterial count (BTTBC) and coliform bacteria count (BTCBC) in a large set of data based on the currently accepted legal limit of BTSCC=400,000/ml. We analysed the database obtained from one of four laboratories offering routine estimation of microbiological indicators and counts of somatic cells in bulk tank milk samples in the Czech Republic during the year 2003 (74,174; 73,921 and 33,020 records of BTSCC, BTTBC and BTCBC estimations, respectively, in milk from 2,769 suppliers). Raw data of BTSCC (with arithmetic mean 220,000/ml; 95th percentile=502,000/ml; 99th percentile=784,000/ml) indicated that the BTSCC limit was exceeded in 12% of samples.

Neutrophil apoptosis during experimentally induced Staphylococcus aureus mastitis.

The objective of this study was to determine whether neutrophil apoptosis and their consequent elimination by macrophages from the mammary gland is modulated by an infection caused by Staphylococcus aureus (S. aureus). The study was performed on twenty mammary glands of 5 virgin heifers.

Activation of phagocytes during initiation and resolution of mammary gland injury induced by lipopolysaccharide in heifers.

The object of the study was the comparative assessment of phagocyte activation during initiation and resolution of mammary gland injury induced by lipopolysaccharide (LPS) or buffered salt solution (PBS) on the basis of the CD14 receptor positivity. The experiments were carried out in 15 clinically normal Holstein x Bohemian Red Pied crossbred heifers, aged 14 to 18 months. Noninflammatory and inflammatory mammary gland injury were induced by intramammary administration of PBS (10 mL) and LPS (10 mL, 1 microg/mL), respectively.