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1.
Br J Dermatol ; 2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-38924720

RESUMO

BACKGROUND: Patient-reported outcome measures (PROMs) are crucial for assessing the impact of dermatological conditions on patients' lives, but the existing dermatology-specific PROMs are not recommended for use according to the Consensus-based Standards for the Selection of Health Measurement Instruments (COSMIN). We developed the Patient-Reported Impact of Dermatological Diseases (PRIDD) measure in partnership with patients. It has strong evidence of content validity, structural validity, internal consistency, acceptability, and feasibility. OBJECTIVES: To test PRIDD's remaining measurement properties and establish the interpretability of scores against the COSMIN criteria using classic and modern psychometric methods. METHODS: A global longitudinal study consisting of two online surveys administered two to four weeks apart. Adults (≥ 18 years) living with a dermatological condition were recruited through the International Alliance of Dermatology Patient Organizations' (GlobalSkin) membership network. Participants completed PRIDD, a demographics questionnaire, and other related measures including the Dermatology Life Quality Index (DLQI). We tested PRIDD's criterion validity, construct validity and responsiveness (Spearman's ρ, independent-samples t-tests and ANOVA), test-retest reliability (interclass correlation coefficient [ICC]), measurement error (Smallest Detectable Change or Limits of Agreement [LoA], distribution-based Minimally Important Change [MIC]), floor and ceiling effects (number of minimum and maximum scores and Person-Item Location Distribution Maps), score bandings (κ coefficient of agreement) and anchor-based MIC. RESULTS: 504 patients with 35 dermatological conditions from 38 countries participated. Criterion validity (ρ = 0.79), construct validity (76% hypotheses met), test-retest validity (ICC = 0.93), and measurement error (LoA = 1.3 < MIC = 4.14) were sufficient. Floor and ceiling effects were in the acceptable range (< 15%). Score bandings were determined (κ = 0.47), however, the anchor-based MIC could not be calculated due to an insufficient anchor. CONCLUSIONS: PRIDD is a valid and reliable tool to evaluate the impact of dermatological disease on patients' lives in research and clinical practice. It is the first dermatology-specific PROM to meet the COSMIN criteria. These results support the value of developing and validating PROMs with a patient-centred approach and using classic and modern psychometric methods. Further testing of responsiveness and MIC, cross-cultural translation, linguistic validation, and global data collection are planned.

2.
Br J Dermatol ; 190(5): 718-728, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38064666

RESUMO

BACKGROUND: Existing dermatology-specific Patient-Reported Outcome Measures (PROMs) do not fully capture the substantial physical, psychological and social impact of dermatological conditions on patients' lives and are not recommended for use according to the COSMIN criteria. Most were developed with insufficient patient involvement and relied on classical psychometric methods. We are developing the new Patient-Reported Impact of Dermatological Diseases (PRIDD) measure for use in research and clinical practice in partnership with patients. OBJECTIVES: To examine the factor structure of PRIDD, determine the definitive selection of items for each subscale, and establish structural validity and internal consistency through classical and modern psychometric methods. METHODS: Two cross-sectional online surveys were conducted. Adults (≥ 18 years) worldwide living with a dermatological condition were recruited through the membership network of the International Alliance of Dermatology Patient Organizations (GlobalSkin). They completed the PRIDD questionnaire and a demographics questionnaire via an online survey. We examined missing data and distribution of scores for each item. The factor structure was assessed using confirmatory and exploratory factor analysis (Survey 1). Internal consistency was examined using Cronbach's α. Rasch measurement theory analyses were conducted, including iterative assessment of rating scale function, fit to the Rasch model, unidimensionality, reliability, local dependence, targeting and differential item functioning (DIF) (Surveys 1 and 2). RESULTS: Participants in Surveys 1 and 2 numbered 483 and 504 people, respectively. All items had ≤ 3% missing scores and all five response options were used. A four-factor model showed the best fit. PRIDD and all four subscales were internally consistent but showed some misfit to the Rasch measurement model. Adjustments were made to rectify disordered thresholds, remove misfitting items, local dependency and DIF, and improve targeting. The resulting 16-item version and subscales fit the Rasch model, showed no local dependency or DIF at the test level, and were well targeted. CONCLUSIONS: This field test study produced the final PRIDD measure, consisting of 16 items across four domains. The data triangulated and refined the conceptual framework of impact and provide evidence of PRIDD's structural validity and internal consistency. The final step in the development and validation of the PRIDD measure is to test the remaining measurement properties.


Assuntos
Medidas de Resultados Relatados pelo Paciente , Exame Físico , Adulto , Humanos , Estudos Transversais , Reprodutibilidade dos Testes , Psicometria/métodos , Inquéritos e Questionários
3.
Front Med (Lausanne) ; 10: 1020523, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37215711

RESUMO

Background: The Global Research on the Impact of Dermatological Diseases (GRIDD) team is developing the new Patient-Reported Impact of Dermatological Diseases (PRIDD) measure of the impact of dermatological conditions on the patient's life, in partnership with patients. To develop PRIDD, we conducted a systematic review, followed by a qualitative interview study with 68 patients worldwide and subsequently a global Delphi survey of 1,154 patients to ensure PRIDD items were meaningful and important to patients. Objective: To pilot test PRIDD with patients with dermatological conditions, focusing on its content validity (comprehensiveness, comprehensibility, and relevance), acceptability, and feasibility. Methods: We conducted a theory-led qualitative study using the Three-Step Test-Interview method of cognitive interviewing. Three rounds of semi-structured interviews were conducted online. Adults (≥ 18 years) living with a dermatological condition and who spoke English sufficiently to take part in the interview were recruited through the International Alliance of Dermatology Patient Organizations' (GlobalSkin) global membership network. The topic guide met the gold-standard COSMIN (Consensus-based Standards for the Selection of Health Measurement Instruments) standards for cognitive interviewing. Analysis followed the thematic analytical model of cognitive interviewing. Results: Twelve people (58% male) representing six dermatological conditions from four countries participated. Overall, patients found PRIDD to be comprehensible, comprehensive, relevant, acceptable, and feasible. Participants were able to discern the conceptual framework domains from the items. Feedback resulted in: the recall period being extended from 1 week to 1 month; removal of the 'not relevant' response option; and changes to the instructions and item ordering and wording to improve clarity and increase respondents' confidence in their ability to respond. These evidence-based adjustments resulted in a 26-item version of PRIDD. Conclusion: This study met the gold-standard COSMIN criteria for the pilot testing of health measurement instruments. The data triangulated our previous findings, in particular the conceptual framework of impact. Our findings illuminate how patients understand and respond to PRIDD and other patient-reported measurement instruments. The results of comprehensibility, comprehensiveness, relevance, acceptability, and feasibility of PRIDD provide evidence of content validity from the target population. The next step in the development and validation of PRIDD is psychometric testing.

4.
Res Sq ; 2023 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-38196606

RESUMO

Natural killer (NK) cells play a critical role in physiologic and pathologic conditions such as pregnancy, infection, autoimmune disease and cancer. In cancer, numerous strategies have been designed to exploit the cytolytic properties of NK cells, with variable success. A major hurdle to NK-cell focused therapies is NK cell recruitment and infiltration into tumors. While the chemotaxis pathways regulating NK recruitment to different tissues are well delineated, the mechanisms human NK cells employ to physically migrate are ill-defined. We show for the first time that human NK cells express fibroblast activation protein (FAP), a cell surface protease previously thought to be primarily expressed by activated fibroblasts. FAP degrades the extracellular matrix to facilitate cell migration and tissue remodeling. We used novel in vivo zebrafish and in vitro 3D culture models to demonstrate that FAP knock out and pharmacologic inhibition restrict NK cell migration, extravasation, and invasion through tissue matrix. Notably, forced overexpression of FAP promotes NK cell invasion through matrix in both transwell and tumor spheroid assays, ultimately increasing tumor cell lysis. Additionally, FAP overexpression enhances NK cells invasion into a human tumor in immunodeficient mice. These findings demonstrate the necessity of FAP in NK cell migration and present a new approach to modulate NK cell trafficking and enhance cell-based therapy in solid tumors.

5.
Teach Learn Med ; 34(5): 504-513, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34763586

RESUMO

PROBLEM: Medical school can be a socially isolating experience, particularly for students underrepresented in medicine. Social isolation and perceptions of not belonging can negatively impact students' academic performance and well-being. Therefore, interventions are needed to support students and these efforts should be appealing, brief, and low-burden. INTERVENTION: Guided by evidence-based approaches, we developed the Build & Belong intervention for medical students as a brief peer-to-peer approach that consisted of four components. First, M3 and M4 students wrote reflections on belonging in medical school. Second, M3 and M4 students video recorded messages for M1 and M2 students using their written reflections. Third, M1 and M2 students watched and discussed the videos in small groups. Fourth, the M1 and M2 students wrote letters to future students. Our intervention differs from previous student belonging interventions in the peer delivery of messages. CONTEXT: The Build & Belong intervention aimed to improve medical students' social belongingness. Using a longitudinal observational study design, the intervention was piloted at a medical school in the Mid-Atlantic United States in 2017-2018. Students completed surveys before and after the intervention. Paired samples tests (t-tests and Wilcoxon) assessed pre- to post-intervention changes in social isolation, social connectedness, and social assurance. IMPACT: Among 63 medical students, with 25.9% from backgrounds underrepresented in medicine, we assessed follow-up outcomes in 38 students. Social isolation scores significantly decreased from baseline (M = 54.8, SD = 7.06) to follow-up (M = 51.3, SD = 6.67; p < .001). Social isolation changes were evident regardless of sex, although males reported a greater reduction (M Δ = -5.32, p < .001) than females (M Δ = -2.79, p = .014). Black/African American students had the largest reduction in social isolation (M Δ = -7.24, p = .010). Social assurance and connectedness scores did not change significantly between baseline and follow-up. Medical students appeared to resonate with messages delivered by more experienced peers (M3s and M4s), particularly messages that normalized feelings of not belonging and strategies to reduce those feelings. LESSONS LEARNED: The Build & Belong intervention appears to reduce social isolation scores among medical students. This pilot test of the Build & Belong intervention provides initial evidence of the effectiveness of a brief, low-cost intervention. Build & Belong may provide a scalable strategy to reduce medical students' social isolation. Our peer-based approach is distinct from administrator-led strategies; peers were seen as trusted and reliable sources of information about belonging and ways to overcome the challenges experienced during medical school.


Assuntos
Estudantes de Medicina , Masculino , Feminino , Humanos , Grupo Associado , Faculdades de Medicina , Isolamento Social , Confiança
6.
J Immunother Cancer ; 9(11)2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34737215

RESUMO

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is projected to be the second leading cause of cancer death in the USA by 2030. Immune checkpoint inhibitors fail to control most PDAC tumors because of PDAC's extensive immunosuppressive microenvironment and poor immune infiltration, a phenotype also seen in other non-inflamed (ie, 'cold') tumors. Identifying novel ways to enhance immunotherapy efficacy in PDAC is critical. Dipeptidyl peptidase (DPP) inhibition can enhance immunotherapy efficacy in other cancer types; however, the impact of DPP inhibition on PDAC tumors remains unexplored. METHODS: We examined the effects of an oral small molecule DPP inhibitor (BXCL701) on PDAC tumor growth using mT3-2D and Pan02 subcutaneous syngeneic murine models in C57BL/6 mice. We explored the effects of DPP inhibition on the tumor immune landscape using RNAseq, immunohistochemistry, cytokine evaluation and flow cytometry. We then tested if BXCL701 enhanced anti-programmed cell death protein 1 (anti-PD1) efficacy and performed immune cell depletion and rechallenged studies to explore the relevance of cytotoxic immune cells to combination treatment efficacy. RESULTS: In both murine models of PDAC, DPP inhibition enhanced NK and T cell immune infiltration and reduced tumor growth. DPP inhibition also enhanced the efficacy of anti-PD1. The efficacy of dual anti-PD1 and BXCL701 therapy was dependent on both CD8+ T cells and NK cells. Mice treated with this combination therapy developed antitumor immune memory that cleared some tumors after re-exposure. Lastly, we used The Cancer Genome Atlas (TCGA) to demonstrate that increased NK cell content, but not T cell content, in human PDAC tumors is correlated with longer overall survival. We propose that broad DPP inhibition enhances antitumor immune response via two mechanisms: (1) DPP4 inhibition increases tumor content of CXCL9/10, which recruits CXCR3+ NK and T cells, and (2) DPP8/9 inhibition activates the inflammasome, resulting in proinflammatory cytokine release and Th1 response, further enhancing the CXCL9/10-CXCR3 axis. CONCLUSIONS: These findings show that DPP inhibition with BXCL701 represents a pharmacologic strategy to increase the tumor microenvironment immune cell content to improve anti-PD1 efficacy in PDAC, suggesting BXCL701 can enhance immunotherapy efficacy in 'cold' tumor types. These findings also highlight the potential importance of NK cells along with T cells in regulating PDAC tumor growth.


Assuntos
Adenocarcinoma/genética , Carcinoma Ductal Pancreático/genética , Inibidores da Dipeptidil Peptidase IV/uso terapêutico , Imunoterapia/métodos , Células Matadoras Naturais/metabolismo , Receptores CXCR3/metabolismo , Linfócitos T/metabolismo , Adenocarcinoma/patologia , Animais , Linfócitos T CD8-Positivos , Carcinoma Ductal Pancreático/patologia , Inibidores da Dipeptidil Peptidase IV/farmacologia , Modelos Animais de Doenças , Humanos , Camundongos , Microambiente Tumoral
7.
Genome Med ; 13(1): 129, 2021 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-34376232

RESUMO

BACKGROUND: Tumor response to therapy is affected by both the cell types and the cell states present in the tumor microenvironment. This is true for many cancer treatments, including immune checkpoint inhibitors (ICIs). While it is well-established that ICIs promote T cell activation, their broader impact on other intratumoral immune cells is unclear; this information is needed to identify new mechanisms of action and improve ICI efficacy. Many preclinical studies have begun using single-cell analysis to delineate therapeutic responses in individual immune cell types within tumors. One major limitation to this approach is that therapeutic mechanisms identified in preclinical models have failed to fully translate to human disease, restraining efforts to improve ICI efficacy in translational research. METHOD: We previously developed a computational transfer learning approach called projectR to identify shared biology between independent high-throughput single-cell RNA-sequencing (scRNA-seq) datasets. In the present study, we test this algorithm's ability to identify conserved and clinically relevant transcriptional changes in complex tumor scRNA-seq data and expand its application to the comparison of scRNA-seq datasets with additional data types such as bulk RNA-seq and mass cytometry. RESULTS: We found a conserved signature of NK cell activation in anti-CTLA-4 responsive mouse and human tumors. In human metastatic melanoma, we found that the NK cell activation signature associates with longer overall survival and is predictive of anti-CTLA-4 (ipilimumab) response. Additional molecular approaches to confirm the computational findings demonstrated that human NK cells express CTLA-4 and bind anti-CTLA-4 antibodies independent of the antibody binding receptor (FcR) and that similar to T cells, CTLA-4 expression by NK cells is modified by cytokine-mediated and target cell-mediated NK cell activation. CONCLUSIONS: These data demonstrate a novel application of our transfer learning approach, which was able to identify cell state transitions conserved in preclinical models and human tumors. This approach can be adapted to explore many questions in cancer therapeutics, enhance translational research, and enable better understanding and treatment of disease.


Assuntos
Antígeno CTLA-4/antagonistas & inibidores , Células Matadoras Naturais/efeitos dos fármacos , Células Matadoras Naturais/metabolismo , Ativação Linfocitária/genética , Modelos Biológicos , Neoplasias/genética , Transcriptoma , Animais , Biomarcadores , Linhagem Celular Tumoral , Biologia Computacional/métodos , Bases de Dados Genéticas , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Inibidores de Checkpoint Imunológico/farmacologia , Inibidores de Checkpoint Imunológico/uso terapêutico , Ipilimumab/farmacologia , Ipilimumab/uso terapêutico , Células Matadoras Naturais/imunologia , Ativação Linfocitária/imunologia , Melanoma/tratamento farmacológico , Melanoma/genética , Melanoma/patologia , Camundongos , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Neoplasias/patologia , Prognóstico , Curva ROC , Resultado do Tratamento
8.
Cancer Immunol Res ; 9(4): 386-400, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33509790

RESUMO

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer death in the United States. Pancreatic tumors are minimally infiltrated by T cells and are largely refractory to immunotherapy. Accordingly, the role of T-cell immunity in pancreatic cancer has been somewhat overlooked. Here, we hypothesized that immune resistance in pancreatic cancer was induced in response to antitumor T-cell immune responses and that understanding how pancreatic tumors respond to immune attack may facilitate the development of more effective therapeutic strategies. We now provide evidence that T-cell-dependent host immune responses induce a PDAC-derived myeloid mimicry phenomenon and stimulate immune resistance. Three KPC mouse models of pancreatic cancer were used: the mT3-2D (Kras+/LSL-G12D; Trp53+/LSL-R172H; Pdx1-Cre) subcutaneous and orthotopic models, as well as the KP1 (p48-CRE/LSL-Kras/Trp53 flox/flox ) subcutaneous model. KPC cancer cells were grown in immunocompetent and immunodeficient C57BL/6 mice and analyzed to determine the impact of adaptive immunity on malignant epithelial cells, as well as on whole tumors. We found that induced T-cell antitumor immunity, via signal transducer and activator of transcription 1 (STAT1), stimulated malignant epithelial pancreatic cells to induce the expression of genes typically expressed by myeloid cells and altered intratumoral immunosuppressive myeloid cell profiles. Targeting the Janus Kinase (JAK)/STAT signaling pathway using the FDA-approved drug ruxolitinib overcame these tumor-protective responses and improved anti-PD-1 therapeutic efficacy. These findings provide future directions for treatments that specifically disable this mechanism of resistance in PDAC.


Assuntos
Carcinoma Ductal Pancreático/tratamento farmacológico , Modelos Animais de Doenças , Nitrilas/farmacologia , Neoplasias Pancreáticas/tratamento farmacológico , Pirazóis/farmacologia , Pirimidinas/farmacologia , Linfócitos T/imunologia , Animais , Carcinoma Ductal Pancreático/imunologia , Carcinoma Ductal Pancreático/patologia , Linhagem Celular Tumoral/transplante , Humanos , Metalotioneína 3 , Camundongos , Camundongos Endogâmicos C57BL , Camundongos SCID , Pâncreas/imunologia , Pâncreas/patologia , Neoplasias Pancreáticas/patologia , Transdução de Sinais/efeitos dos fármacos , Linfócitos T/efeitos dos fármacos , Microambiente Tumoral , Ubiquitina-Proteína Ligases
9.
Cancers (Basel) ; 13(1)2020 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-33379189

RESUMO

Cancer immunotherapy has revolutionized cancer treatment, spurring extensive investigation into cancer immunology and how to exploit this biology for therapeutic benefit. Current methods to investigate cancer-immune cell interactions and develop novel drug therapies rely on either two-dimensional (2D) culture systems or murine models. However, three-dimensional (3D) culture systems provide a potentially superior alternative model to both 2D and murine approaches. As opposed to 2D models, 3D models are more physiologically relevant and better replicate tumor complexities. Compared to murine models, 3D models are cheaper, faster, and can study the human immune system. In this review, we discuss the most common 3D culture systems-spheroids, organoids, and microfluidic chips-and detail how these systems have advanced our understanding of cancer immunology.

10.
Mar Environ Res ; 161: 105122, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32846315

RESUMO

Heavy metal contamination and water quality may alter reproductive capacity of oysters in highly urbanized, eutrophic ecosystems. This study assessed physiological biomarkers and heavy metal body burdens in adult oysters, Crassostrea virginica, placed at a highly urban and reference site. Condition index and Vitellogenin-like proteins were significantly different between sites, but protein concentration and activity of the electron transport system were not. Accumulation of Cd and Hg occurred at both sites, and Cd body burden was greater at the urban site. There was a negative relationship between condition index and Cd body burden at the urban site, while no relationship was found between physiological biomarkers and metal burden at the reference site. The results suggest that oyster condition and reproductive potential may be negatively influenced by the biotic and abiotic factors typically found within urban, eutrophic ecosystems.


Assuntos
Crassostrea , Poluentes Químicos da Água , Animais , Biomarcadores , Ecossistema , Estuários , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
11.
Cancer Metastasis Rev ; 39(3): 783-803, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32601975

RESUMO

Fibroblast activation protein-α (FAP) is a type-II transmembrane serine protease expressed almost exclusively to pathological conditions including fibrosis, arthritis, and cancer. Across most cancer types, elevated FAP is associated with worse clinical outcomes. Despite the clear association between FAP and disease severity, the biological reasons underlying these clinical observations remain unclear. Here we review basic FAP biology and FAP's role in non-oncologic and oncologic disease. We further explore how FAP may worsen clinical outcomes via its effects on extracellular matrix remodeling, intracellular signaling regulation, angiogenesis, epithelial-to-mesenchymal transition, and immunosuppression. Lastly, we discuss the potential to exploit FAP biology to improve clinical outcomes.


Assuntos
Gelatinases/metabolismo , Proteínas de Membrana/metabolismo , Neoplasias/metabolismo , Serina Endopeptidases/metabolismo , Animais , Endopeptidases , Gelatinases/química , Gelatinases/genética , Humanos , Proteínas de Membrana/química , Proteínas de Membrana/genética , Modelos Moleculares , Neoplasias/genética , Neoplasias/patologia , Serina Endopeptidases/química , Serina Endopeptidases/genética , Relação Estrutura-Atividade
12.
Microbiol Resour Announc ; 9(22)2020 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-32467263

RESUMO

Biodiversity monitoring is an essential component of restoration efforts. We sequenced 16S rRNA gene amplicons from sediments and waters of Hunts Point Riverside Park and Soundview Park, located in a historically degraded but recovering urban estuary in New York. In total, 16,165 unique amplicon sequence variants were recovered, and Proteobacteria was the dominant phylum.

13.
Environ Sci Pollut Res Int ; 26(25): 25958-25968, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31273655

RESUMO

To assess the toxicity and accumulation (total and subcellular partitioning) of cadmium (Cd) and mercury (Hg), juvenile eastern oysters, Crassostrea virginica, were exposed for 4 weeks to a range of concentrations (Control, Low (1×), and High (4×)). Despite the 4-fold increase in metal concentrations, oysters from the High-Cd treatment (2.4 µM Cd) attained a body burden that was only 2.4-fold greater than that of the Low-Cd treatment (0.6 µM Cd), while oysters from the High-Hg treatment (0.056 µM Hg) accumulated 8.9-fold more Hg than those from the Low-Hg treatment (0.014 µM Hg). This fold difference in total Cd burdens was, in general, mirrored at the subcellular level, though binding to heat-denatured proteins in the High-Cd treatment was depressed (only 1.6-fold higher than the Low-Cd treatment). Mercury did not appear to appreciably partition to the subcellular fractions examined in this study, with the fold difference in accumulation between the Low- and High-Hg treatments ranging from 1.5-fold (heat-stable proteins) to 4.6-fold (organelles). Differences in toxicological impairments (reductions in condition index, protein content, and ETS activity) exhibited by oysters from the High-Cd treatment may be partially due to the nature of how different metals partition to subcellular components in the oysters, though exact mechanisms will require further examination.


Assuntos
Crassostrea/metabolismo , Mercúrio/metabolismo , Poluentes Químicos da Água/toxicidade , Animais , Cádmio/metabolismo , Crassostrea/química , Temperatura Alta , Mercúrio/química , Poluentes Químicos da Água/química
14.
Vet Clin North Am Food Anim Pract ; 20(3): 687-701, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15471631

RESUMO

Recent studies in high-producing dairy cows have demonstrated the dry period requirement is greatly influenced by parity and management practice. Multiparous cows that were continuously milked and treated with bST demonstrated negligible production losses in the next lactation. First-lactation heifers, however, demonstrated large reductions in milk yield. These reductions were not overcome by using bST or IMF the next lactation. No studies have been performed examining use of LDPP or SDPP in combination with bST and IMF on the dry-period requirement. Cows that are continuously milked demonstrated higher feed intakes during the peripartum period, which may greatly improve metabolic health. Future studies must examine potential benefits of continuous milking on health in the next lactation.


Assuntos
Bovinos/fisiologia , Indústria de Laticínios/métodos , Hormônio do Crescimento/administração & dosagem , Lactação/fisiologia , Paridade/fisiologia , Animais , Feminino , Lactação/efeitos dos fármacos , Fotoperíodo
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