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Persson Waller K, Lundberg Å, Börjesson S, Nyman AK. Intramammary infections and risk factors in freshly calved heifers in Swedish dairy herds. J Dairy Sci 2023; 106:7893-7907. [PMID: 37210369 DOI: 10.3168/jds.2022-22995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 04/07/2023] [Indexed: 05/22/2023]
Abstract
Subclinical mastitis can be common among freshly calved heifers (FCH), but the prevalence differs between herds, possibly due to variation in risk factors. The aims of this observational study were to identify differences in occurrence of intramammary infection (IMI) in FCH between herds with documented good or poorer first-parity udder health based on cow somatic cell count (CSCC) in early lactation, and to study herd differences in animal factors important for udder health, such as udder and hock skin lesions and animal cleanliness. Three groups of herds were included: those with high proportions of FCH with low CSCC (≤75,000 cells/mL) at the first 2 milk recordings after calving (LL), herds with high proportions of FCH with high CSCC (>100,000 cells/mL) at the first and low CSCC at the second recording (HL), and herds with high proportions of FCH with high CSCC at both recordings (HH). Thirty-nine herds (13 LL, 11 HL, 15 HH) were visited 3 times during a 12-mo period for observation of cleanliness and hock lesions, and sampling of udder and teat skin using swab cloths of milk-fed calves, early-pregnant heifers, and late-pregnant heifers. In 25 (9 LL, 9 HL, 7 HH) udder quarter samples from colostrum and milk on d 3 to 4 after calving were taken by the farmers from FCH during one year. The farmers also provided information on calving (individual or group), use of restraint and oxytocin at milking, and presence of teat and udder skin lesions. Bacterial growth in swab samples and quarter samples was investigated by culturing, and a selection of isolates was genotyped using whole-genome sequencing. Cleanliness, hock and udder skin lesions other than udder-thigh dermatitis, and growth of bacteria in swab samples did not differ between herd groups. It was more common that FCH from LL herds, compared with FCH in HH and HL herds, calved in a group of animals. Use of restraint at milking was more common in LL herds than in HH herds, whereas presence of udder-thigh dermatitis was lowest in LL herds. Specific infection was found in 14% of 5,593 quarter samples from 722 FCH. The most common IMI was Staphylococcus chromogenes. Growth of Staphylococcus simulans was more common in HH than in LL and HL herds. In colostrum samples, Staphylococcus haemolyticus was more common in HL and HH than in LL herds. The proportion of quarters with the same specific infection at both samplings was higher in HH than in LL herds and tended to be higher in HH than in HL herds. The proportion of quarters with Staph. chromogenes IMI at both samplings tended to differ between herd groups and was highest in HH herds. Whole-genome sequencing found the same sequence type of Staph. chromogenes and Staphylococcus aureus in both samples in almost all quarters with the same infection at both samplings. The differences in IMI between herd groups were in line with the higher somatic cell count in HH herds. The reasons for the predominance of Staph. chromogenes IMI in FCH need further studies.
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Affiliation(s)
- K Persson Waller
- Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute (SVA), SE-751 89 Uppsala, Sweden.
| | | | - S Börjesson
- School of Health Science, Örebro University, Örebro, SE-701 82, Sweden
| | - A-K Nyman
- Växa, SE-104 25 Stockholm, Sweden; Department of Clinical Sciences, Swedish University of Agricultural Sciences (SLU), SE-750 07 Uppsala, Sweden
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Persson Waller K, Myrenås M, Börjesson S, Kim H, Widerström M, Monsen T, Sigurðarson Sandholt AK, Östlund E, Cha W. Genotypic characterization of Staphylococcus chromogenes and Staphylococcus simulans from Swedish cases of bovine subclinical mastitis. J Dairy Sci 2023; 106:7991-8004. [PMID: 37641317 DOI: 10.3168/jds.2023-23523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 05/23/2023] [Indexed: 08/31/2023]
Abstract
Staphylococcus chromogenes and Staphylococcus simulans are commonly found in intramammary infections (IMI) associated with bovine subclinical mastitis, but little is known about genotypic variation and relatedness within species. This includes knowledge about genes encoding antimicrobial resistance (AMR) and potential virulence factors (pVF). The aim of this study was therefore to investigate these aspects by whole-genome sequencing of milk isolates from Swedish dairy cows with subclinical mastitis in an observational study. We also wanted to study if specific genotypes were associated with persistent IMI and the inflammatory response at udder quarter level. In total, 105 and 118 isolates of S. chromogenes and S. simulans, respectively, were included. Isolates were characterized using a 7-locus multilocus sequence typing (7-MLST), core genome analysis and in-silico analysis of AMR and pVF genes. Forty-seven sequence types (ST) and 7 core genome clusters of S. chromogenes were identified, and the most common ST were ST-6 and ST-109, both belonging to cluster VII. A 7-locus MLST scheme for S. simulans was not available, but 3 core genome clusters and 5 subclusters were described. Overall, substantial variation in ST and clusters among cows and herds were found in both species. Some ST of S. chromogenes were found in several herds, indicating spread between herds. Moreover, within-herd spread of the same genotype was observed for both species. Only a few AMR genes [blaZ, strpS194, vga(A)] were detected in a limited number of isolates, with the exception of blaZ coding for β-lactamase, which was identified in 22% of the isolates of S. chromogenes with ST-19, ST-102, and ST-103 more commonly carrying this gene compared with other ST. However, the blaZ gene was not identified in S. simulans. The average total number of pVF detected per isolate was similar in S. chromogenes (n = 30) and S. simulans (n = 33), but some variation in total numbers and presence of specific pVF or functional groups of pVF, was shown between ST/clusters within species. Differences in inflammatory response and potentially in persistent IMI at udder quarter level were found between S. chromogenes subtypes but not between S. simulans subtypes. In conclusion, the results from the present study generates new insight into the epidemiology of bovine S. chromogenes and S. simulans IMI, which can have implications for future prevention and antimicrobial treatment of infections related to these species.
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Affiliation(s)
- K Persson Waller
- Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute (SVA), SE-751 89 Uppsala, Sweden.
| | - M Myrenås
- Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute (SVA), SE-751 89 Uppsala, Sweden
| | - S Börjesson
- School of Health Science, Örebro University, Örebro, SE-701 82, Sweden
| | - H Kim
- Department of Disease Control and Epidemiology, National Veterinary Institute (SVA), SE-751 89 Uppsala, Sweden
| | - M Widerström
- Department of Clinical Microbiology, Umeå University, Umeå SE-90185, Sweden
| | - T Monsen
- Department of Clinical Microbiology, Umeå University, Umeå SE-90185, Sweden
| | | | - E Östlund
- Department of Microbiology, National Veterinary Institute (SVA), SE-75189 Uppsala, Sweden
| | - W Cha
- Department of Disease Control and Epidemiology, National Veterinary Institute (SVA), SE-751 89 Uppsala, Sweden
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Bi Z, Sun C, Börjesson S, Chen B, Ji X, Berglund B, Wang M, Nilsson M, Yin H, Sun Q, Hulth A, Wang Y, Wu C, Bi Z, Nilsson LE. Identical genotypes of community-associated MRSA (ST59) and livestock-associated MRSA (ST9) in humans and pigs in rural China. Zoonoses Public Health 2018; 65:367-371. [PMID: 29377579 DOI: 10.1111/zph.12443] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/24/2017] [Indexed: 11/29/2022]
Abstract
This study investigated the prevalence of MRSA in samples taken in households, with and without backyard pigs in villages in a rural area of Shandong Province, China. Community-associated MRSA and livestock-associated MRSA, belonging to ST59 and ST9, respectively, were identified in both humans and pigs. The genotypic and phenotypic comparison of isolates indicates that bidirectional transmission of MRSA has occurred between humans and pigs in the villages.
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Affiliation(s)
- Z Bi
- Shandong Provincial Key Laboratory of Infectious Disease Control and Prevention, Shandong Center for Disease Control and Prevention, Jinan, China
| | - C Sun
- Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - S Börjesson
- Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute (SVA), Uppsala, Sweden
| | - B Chen
- Shandong Provincial Key Laboratory of Infectious Disease Control and Prevention, Shandong Center for Disease Control and Prevention, Jinan, China
| | - X Ji
- Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - B Berglund
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - M Wang
- Shandong Provincial Key Laboratory of Infectious Disease Control and Prevention, Shandong Center for Disease Control and Prevention, Jinan, China
| | - M Nilsson
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - H Yin
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Q Sun
- School of Health Care Management, Shandong University, Shandong, China.,Key Laboratory of Health Economics and Policy Research, NHFPC (Shandong University), Shandong, China
| | - A Hulth
- Public Health Agency of Sweden, Solna, Sweden
| | - Y Wang
- Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - C Wu
- Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Z Bi
- Shandong Provincial Key Laboratory of Infectious Disease Control and Prevention, Shandong Center for Disease Control and Prevention, Jinan, China
| | - L E Nilsson
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
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Lundberg Å, Nyman AK, Aspán A, Börjesson S, Unnerstad HE, Waller KP. Udder infections with Staphylococcus aureus, Streptococcus dysgalactiae, and Streptococcus uberis at calving in dairy herds with suboptimal udder health. J Dairy Sci 2016; 99:2102-2117. [PMID: 26805990 DOI: 10.3168/jds.2015-9487] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 12/04/2015] [Indexed: 11/19/2022]
Abstract
Udder infections with Staphylococcus aureus, Streptococcus dysgalactiae, and Streptococcus uberis are common causes of bovine mastitis. To study these pathogens in early lactation, a 12-mo longitudinal, observational study was carried out in 13 herds with suboptimal udder health. The aims of the study were to investigate the occurrence of these pathogens and to identify if presence of the 3 pathogens, and of genotypes within the pathogens, differed with respect to herd, season, and parity. Quarter milk samples, collected at calving and 4 d in milk (DIM), were cultured for the 3 pathogens. Genotyping of staphylococcal and streptococcal isolates was performed using spa typing and pulsed-field gel electrophoresis, respectively. For each of the 3 pathogens, cows with an udder infection at calving or 4 DIM were allocated to 1 of 4 infection types: cleared (pathogen present only at calving), persistent (pathogen present in the same quarter at calving and 4 DIM), new (pathogen present only at 4 DIM), or cleared/new (pathogen present in 1 quarter at calving and in another quarter at 4 DIM). Associations between season or parity and overall occurrence of pathogens or infection types were determined using univariable mixed-effect logistic-regression models and the Fisher's exact test, respectively. The most commonly occurring pathogen was Staph. aureus, followed by Strep. dysgalactiae and Strep. uberis. Persistent infections were the most common infection type among Staph. aureus-infected cows, whereas cleared infections were the most common among Strep. dysgalactiae- and Strep. uberis-positive cows. The proportion of cows with persistent Staph. aureus infections and the proportion of cows having a Strep. uberis infection at calving or 4 DIM were higher in the multiparous cows than in primiparous cows. Infections with Strep. dysgalactiae were less common during the early housing season than during the late housing or pasture seasons, whereas persistent Strep. uberis infections were less common during the pasture season than during the late housing season. The relative occurrence of the 3 pathogens, infection types of each pathogen, and genotype diversity of each pathogen throughout the year or in different seasons and parities varied among the herds, indicating that underlying factors predisposing for udder infections at calving differ between herds. Genotyping of bacterial isolates gave important insight into how such infection patterns differed within and between herds. These findings emphasize the need to choose preventive strategies for each individual herd.
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Affiliation(s)
- Å Lundberg
- Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, SE-751 89 Uppsala, Sweden; Department of Clinical Sciences, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
| | - A-K Nyman
- Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, SE-751 89 Uppsala, Sweden
| | - A Aspán
- Department of Bacteriology, National Veterinary Institute, SE-751 89 Uppsala, Sweden
| | - S Börjesson
- Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, SE-751 89 Uppsala, Sweden
| | - H Ericsson Unnerstad
- Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, SE-751 89 Uppsala, Sweden
| | - K Persson Waller
- Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, SE-751 89 Uppsala, Sweden; Department of Clinical Sciences, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden.
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Börjesson S, Gómez-Sanz E, Ekström K, Torres C, Grönlund U. Staphylococcus pseudintermedius can be misdiagnosed as Staphylococcus aureus in humans with dog bite wounds. Eur J Clin Microbiol Infect Dis 2014; 34:839-44. [PMID: 25532507 DOI: 10.1007/s10096-014-2300-y] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 12/07/2014] [Indexed: 11/25/2022]
Abstract
The purpose of this study was to investigate whether S. pseudintermedius is misdiagnosed as S. aureus by clinical laboratories when isolated from humans with dog bite wounds. In addition, we attempted to determine whether S. pseudintermedius isolates related to dog bite wounds share phenotypic and genotypic traits. S. pseudintermedius was identified by PCR targeting the nuc gene. Isolates were tested for antibiotic susceptibility using VetMIC GP-mo microdilution panels. The occurrence of genes encoding leukocidins, exfoliatins, pyrogenic toxin superantigens and enterotoxins was determined by PCR. The relatedness of S. pseudintermedius isolates was investigated using Multi Locus Sequence Typing (MLST). Out of 101 isolates defined as S. aureus by human clinical microbiology laboratories, 13 isolates were re-identified as S. pseudintermedius and one isolate was confirmed to carry the mecA gene, i.e. methicillin-resistant (MRSP). The MRSP isolate was also defined as multi-resistant. Two methicillin-susceptible S. pseudintermedius isolates were also multi-resistant and five were susceptible to all antibiotics tested. With the exception of three S. pseudintermedius isolates belonging to multi locus sequence type (MLST) 158, all the isolates belonged to unique STs. All isolates contained lukS/F-I, siet and se-int, and expA were identified in two isolates and expB and sec canine-sel in one isolate respectively. S. pseudintermedius is frequently misdiagnosed as S. aureus from humans with dog bite wounds showing that it can act as an opportunistic pathogen in humans. No common phenotypic and genotypic traits shared by the S. pseudintermedius isolates could be identified.
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Affiliation(s)
- S Börjesson
- Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute (SVA), SE751 89, Uppsala, Sweden,
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Börjesson S, Jernberg C, Brolund A, Edquist P, Finn M, Landén A, Olsson-Liljequist B, Tegmark Wisell K, Bengtsson B, Englund S. Characterization of plasmid-mediated AmpC-producing E. coli from Swedish broilers and association with human clinical isolates. Clin Microbiol Infect 2013; 19:E309-11. [DOI: 10.1111/1469-0691.12192] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 01/15/2013] [Accepted: 02/07/2013] [Indexed: 11/28/2022]
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Lindstedt BA, Torpdahl M, Vergnaud G, Le Hello S, Weill FX, Tietze E, Malorny B, Prendergast DM, Ní Ghallchóir E, Lista RF, Schouls LM, Söderlund R, Börjesson S, Åkerström S. Use of multilocus variable-number tandem repeat analysis (MLVA) in eight European countries, 2012. Euro Surveill 2013; 18:20385. [DOI: 10.2807/ese.18.04.20385-en] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Genotyping of important medical or veterinary prokaryotes has become a very important tool during the last decades. Rapid development of fragment-separation and sequencing technologies has made many new genotyping strategies possible. Among these new methods is multilocus variable-number tandem repeat analysis (MLVA). Here we present an update on the use of MLVA in eight European countries (Denmark, France, Germany, Ireland, Italy, the Netherlands, Norway and Sweden). Researchers in Europe have been active in developing and implementing a large array of different assays. MLVA has been used as a typing tool in several contexts, from aiding in resolving outbreaks of food-borne bacteria to typing organisms that may pose a bioterrorist threat, as well as in scientific studies.
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Affiliation(s)
- B A Lindstedt
- Division of Infectious Diseases Control, Norwegian Institute of Public Health, Oslo, Norway
| | - M Torpdahl
- Department of Microbiological Surveillance and Research, Statens Serum Institut, Copenhagen, Denmark
| | - G Vergnaud
- Direction Générale de l'Armement (DGA)/Mission pour la Recherche et l’Innovation Scientifique (MRIS), Bagneux, France
- Université Paris-Sud, Institut de Génétique et Microbiologie, Unités Mixtes de Recherche (UMR) 8621, Orsay, France
| | - S Le Hello
- Institut Pasteur, Unité de Recherche et d'Expertise des Bactéries Pathogènes Entériques, Centre National de Référence E. coli/Shigella/Salmonella, Paris, France
| | - F X Weill
- Institut Pasteur, Unité de Recherche et d'Expertise des Bactéries Pathogènes Entériques, Centre National de Référence E. coli/Shigella/Salmonella, Paris, France
| | - E Tietze
- National Reference Center for Salmonella and other Enterics, Robert Koch Institute, Wernigerode Branch, Wernigerode, Germany
| | - B Malorny
- Federal Institute for Risk Assessment (BfR) National Salmonella Reference Laboratory Department Biological Safety, Berlin, Germany
| | - D M Prendergast
- Central Veterinary Research Laboratory, Department of Agriculture, Food and the Marine, Kildare, Ireland
| | - E Ní Ghallchóir
- Central Veterinary Research Laboratory, Department of Agriculture, Food and the Marine, Kildare, Ireland
| | - R F Lista
- Health Corps Italian Army, Department of Molecular Biology, Immunology and Experimental Medicine, Army Medical and Veterinary Research Center, Rome, Italy
| | - L M Schouls
- Laboratory for Infectious Diseases and Perinatal Screening (LIS), Centre for Infectious Disease Control Netherlands (CIb), National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - R Söderlund
- The National Veterinary Institute (SVA), Uppsala, Sweden
| | - S Börjesson
- The National Veterinary Institute (SVA), Uppsala, Sweden
| | - S Åkerström
- The National Veterinary Institute (SVA), Uppsala, Sweden
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Rota A, Milani C, Corrò M, Drigo I, Börjesson S. Misuse of antimicrobials and selection of methicillin-resistant Staphylococcus pseudintermedius strains in breeding kennels: genetic characterization of bacteria after a two-year interval. Reprod Domest Anim 2012; 48:1-6. [PMID: 22551469 DOI: 10.1111/j.1439-0531.2012.02012.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Methicillin-resistant Staphylococcus pseudintermedius (MRSP) strains have been isolated from dogs with increasing frequency; prolonged or excessive use of antimicrobials is associated with the selection of MRSP, and misuse of antimicrobials is frequent in breeding kennels. This study was carried out in two breeding kennels (A and B) in which we had isolated MRSP in 2008: the aim was to assess colonization of previously positive bitches and of other bitches sharing the same environment and to assess the genetic profile of both the old and the new strains [spa typing, staphylococcal cassette chromosome mec (SCCmec) typing and Pulsed-field Gel Electrophoresis (PFGE)]. Six animals from Kennel A (two from 2008) and eight from Kennel B (one from 2008) were tested: 16 MRSP strains were isolated only from bitches housed in Kennel B. Old and new isolates were mecA positive, resulted spa type t02 and carried SSCmec II-III. PGFE showed that all isolates were related and belonged to the main clone lineage dominating in Europe, ST71-J-t02-II-III. Kennels A and B differ in the use of antimicrobials, which has been reduced over time in Kennel A, while has remained excessive in Kennel B, where many agents belonging to different classes (third-generation cephalosporins, fluoroquinolones, macrolids) are administered to dogs, without veterinary supervision, especially around parturition. Misuse of antimicrobials is the key factor for the selection of MRSP strains in healthy dogs and for their persistence over time. Dog breeders should be aware that infections caused by multiresistant bacteria have very limited therapeutical options and represent a huge challenge for animal health.
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Affiliation(s)
- A Rota
- Dipartimento di Patologia Animale, Università di Torino, Grugliasco, Italy.
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Börjesson S, Matussek A, Melin S, Löfgren S, Lindgren P. Methicillin-resistantStaphylococcus aureus(MRSA) in municipal wastewater: an uncharted threat? J Appl Microbiol 2010; 108:1244-51. [DOI: 10.1111/j.1365-2672.2009.04515.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Wirestam R, Knutsson L, Risberg J, Börjesson S, Larsson EM, Gustafson L, Passant U, Ståhlberg F. Attempts to improve absolute quantification of cerebral blood flow in dynamic susceptibility contrast magnetic resonance imaging: a simplified T1-weighted steady-state cerebral blood volume approach. Acta Radiol 2007; 48:550-6. [PMID: 17520432 DOI: 10.1080/02841850701280825] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND Attempts to retrieve absolute values of cerebral blood flow (CBF) by dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) have typically resulted in overestimations. PURPOSE To improve DSC-MRI CBF estimates by calibrating the DSC-MRI-based cerebral blood volume (CBV) with a corresponding T1-weighted (T1W) steady-state (ss) CBV estimate. MATERIAL AND METHODS 17 volunteers were investigated by DSC-MRI and 133Xe SPECT. Steady-state CBV calculation, assuming no water exchange, was accomplished using signal values from blood and tissue, before and after contrast agent, obtained by T1W spin-echo imaging. Using steady-state and DSC-MRI CBV estimates, a calibration factor K = CBV(ss)/CBV(DSC) was obtained for each individual. Average whole-brain CBF(DSC) was calculated, and the corrected MRI-based CBF estimate was given by CBF(ss) = K x CBF(DSC). RESULTS Average whole-brain SPECT CBF was 40.1+/-6.9 ml/min x 100 g, while the corresponding uncorrected DSC-MRI-based value was 69.2+/-13.8 ml/min x 100 g. After correction with the calibration factor, a CBF(ss) of 42.7+/-14.0 ml/min x 100 g was obtained. The linear fit to CBF(ss)-versus-CBF(SPECT) data was close to proportionality (R = 0.52). CONCLUSION Calibration by steady-state CBV reduced the population average CBF to a reasonable level, and a modest linear correlation with the reference 133Xe SPECT technique was observed. Possible explanations for the limited accuracy are, for example, large-vessel partial-volume effects, low post-contrast signal enhancement in T1W images, and water-exchange effects.
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Affiliation(s)
- R Wirestam
- Department of Medical Radiation, Lund University, Lund, Sweden.
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Grahn A, Hemdal B, Andersson I, Ruschin M, Thilander-Klang A, Börjesson S, Tingberg A, Mattsson S, Håkansson M, Båth M, Månsson LG, Medin J, Wanninger F, Panzer W. Clinical evaluation of a new set of image quality criteria for mammography. Radiat Prot Dosimetry 2005; 114:389-94. [PMID: 15933143 DOI: 10.1093/rpd/nch573] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The European Commission (EC) quality criteria for screen-film mammography are used as a tool to assess image quality. A new set of criteria was developed and initially tested in a previous study. In the present study, these criteria are further evaluated using screen-film mammograms that have been digitised, manipulated to simulate different image quality levels and reprinted on film. Expert radiologists have evaluated these manipulated images using both the original (EC) and the new criteria. A comparison of three different simulated dose levels reveals that the new criteria yield a larger separation of image criteria scores than the old ones. These results indicate that the new set of image quality criteria has a higher discriminative power than the old set and thus seems to be more suitable for evaluation of image quality in mammography.
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Affiliation(s)
- A Grahn
- Department of Medical Radiation Physics, Lund University, Malmö University Hospital, 205 02 Malmö, Sweden.
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12
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Ruschin M, Hemdal B, Andersson I, Börjesson S, Håkansson M, Båth M, Grahn A, Tingberg A. Threshold pixel size for shape determination of microcalcifications in digital mammography: a pilot study. Radiat Prot Dosimetry 2005; 114:415-23. [PMID: 15933149 DOI: 10.1093/rpd/nch561] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The effect of pixel size on shape determination in screening digital mammography systems was studied using a shape identification task as the measured outcome. Ten microcalcifications on screen-films were digitised to a range of pixel sizes (2.5-200 microm) and extracted from computed radiography (CR) images (50 microm) acquired under equivalent imaging conditions. Fifteen observers attempted to identify the shape of each microcalcification at each pixel size. The results were collated to provide a fraction of correct responses vs. pixel size curve for each microcalcification. Averaging over all shapes, pixel values >100 microm lead to a significant decrease in shape determination ability (p < 0.01) for digitised screen-film. For CR images, half the shapes were not properly identified. Hence, although 20-100 microm was sufficient for microcalcification shape determination for digitised screen-film images, 50 microm was only borderline sufficient for the CR digital images.
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Affiliation(s)
- M Ruschin
- Department of Medical Radiation Physics, Lund University, Malmö University Hospital, Malmö, Sweden.
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Hemdal B, Andersson I, Grahn A, Håkansson M, Ruschin M, Thilander-Klang A, Båth M, Börjesson S, Medin J, Tingberg A, Månsson LG, Mattsson S. Can the average glandular dose in routine digital mammography screening be reduced? A pilot study using revised image quality criteria. Radiat Prot Dosimetry 2005; 114:383-8. [PMID: 15933142 DOI: 10.1093/rpd/nch555] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
There is a need for tools that in a simple way can be used for the evaluation of image quality related to clinical requirements in mammography. The aim of this work was to adjust the present European image quality criteria to be relevant also for digital mammography images, and to use as simple and as few criteria as possible. A pilot evaluation of the new set of criteria was made with mammograms of 28 women from a General Electric Senographe 2000D full-field digital mammography system. One breast was exposed using the standard automatic exposure mode, the other using about half of that absorbed dose. Three experienced radiologists evaluated the images using visual grading analysis technique. The results indicate that the new quality criteria can be used for the evaluation of image quality related to clinical requirements in digital mammography in a simple way. The results also suggest that absorbed doses for the mammography system used may be substantially reduced.
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Affiliation(s)
- B Hemdal
- Department of Medical Radiation Physics, Lund University, Malmö University Hospital, SE-205 02 Malmö, Sweden.
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Tishelman C, Bernhardson BM, Bâckman L, Ternestedt BM, Börjesson S, Blomberg K, Johansson E, Levealâhti H, Axelsson K. Improving quality of care for patients with advanced cancer through a knowledge exchange program. Eur J Cancer 2001. [DOI: 10.1016/s0959-8049(01)81958-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Fredrikson M, Hursti TJ, Steineck G, Fürst CJ, Börjesson S, Peterson C. Delayed chemotherapy-induced nausea is augmented by high levels of endogenous noradrenaline. Br J Cancer 1994; 70:642-5. [PMID: 7917910 PMCID: PMC2033385 DOI: 10.1038/bjc.1994.364] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The relation between pretreatment night-time urinary catecholamine excretion and chemotherapy-induced nausea and vomiting was studied. The first cohort included 17 women and three men with various cancer forms receiving low or moderately emetogenic chemotherapy. The second cohort included 42 women receiving cisplatinum (50 mg m-2) for ovarian cancer and ondansetron as an antiemetic (8 mg i.v. x 3 at chemotherapy and 8 mg p.o. x 3 for 5 days). Relatively higher noradrenaline, but not adrenaline, excretion was associated with an increased intensity of delayed nausea following treatment. Vomiting was not consistently related to the excretion of either catecholamine. The results indicate that noradrenaline modulates delayed nausea resulting from chemotherapy.
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Affiliation(s)
- M Fredrikson
- Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden
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Börjesson S. [Care of the dying. Experiences from a hospice--correct care of the dying]. Vardfacket 1991; 15:XI-XIII. [PMID: 1719711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Andersson RG, Börjesson S, Nilsson KB. Effects of isoprenaline and 1-methyl-3-isobutylxanthine on cyclic nucleotides and cyclic AMP-dependent protein kinase in rabbit colon smooth muscle. Acta Pharmacol Toxicol (Copenh) 1980; 46:8-13. [PMID: 6153852 DOI: 10.1111/j.1600-0773.1980.tb02412.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
From a homogenate of rabbit colon a crude protein kinase was isolated. The phosphorylation of histone by this enzyme was maximal at 20 mM NaF. Higher concentrations inhibited the incorporation of 32P. After chromatography on a DEAE-cellulose column the crude protein kinase was partly purified. Cyclic AMP and cGMP stimulated the protein kinases eluted at 0.09 M-NaCl (Type I) and at approximately 0.2M-NaCl (Type II). The main peak was of type II. Mix (1-methyl-3-isobutylxanthine) relaxed the rabbit colon muscle. The increase in the protein kinase activity was closely correlated to the changes of the cAMP level. The cGMP content was also increased. Isoprenaline increased the cAMP level and the protein kinase activity of the colon muscle. Isoprenaline had no effect on the cGMP level. It is suggested that relaxing drugs which increase the cAMP level of rabbit colon muscle may activate protein kinase. This enzyme might be an important factor of the cAMP mediated relaxing mechanism.
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