RESUMO
Climate change is worsening with tangible effects on our healthcare system. This review aims to examine the repercussions of the climate change on nephrology and explore potential strategies to mitigate its impact. This review examines dialysis's environmental impact, resource recycling methods, and plant-based diets for kidney health. Recent research highlights the advantages of plant-based diets in managing and preventing chronic kidney disease (CKD) and its complications. Integrating these practices can significantly lessen the environmental impact of nephrology. PURPOSE OF REVIEW: The aim of this study is to discuss the bidirectional relationship of climate change and kidney disease and the impact of nephrology on climate change and to discuss potential solutions. RECENT FINDINGS: Each dialysis session consumes significant amounts of resource; reusing them will aid the environment. Plant-based diets slow renal disease and have a lower carbon footprint, making them ecologically friendly. SUMMARY: Climate change is a growing threat to population health and healthcare. Rising temperatures raise the risk of kidney problems. Dialysis treatments also impact the environment through its high resource requirements while generating high volumes of waste and greenhouse gases. Opportunities exist to reduce the environmental impact of dialysis treatments. Plant-based diets serve to benefit both kidney disease and the environment.
Assuntos
Nefrologia , Insuficiência Renal Crônica , Humanos , Diálise Renal/efeitos adversos , Diálise Renal/métodos , Mudança Climática , Meio Ambiente , Insuficiência Renal Crônica/diagnóstico , Insuficiência Renal Crônica/epidemiologia , Insuficiência Renal Crônica/terapiaRESUMO
OBJECTIVE: In people with chronic kidney disease (CKD), hyperphosphatemia is a risk factor for mortality. Though unproven, dietary phosphorus control is considered essential in CKD. Although dietary and serum phosphorus are correlated, phosphorus from plant foods rich in phytate is less bioavailable than from animal and processed foods. Yogurt, valued for its low phosphorus and high protein, may be detrimental in CKD due to animal protein content. Plant-based yogurts (PBYs) might offer similar benefits without the downsides of animal protein, but little is known about their phosphorus content. DESIGN AND METHODS: Protein contents and phosphorus additives were gathered from nutrition labels of several PBYs, including almond, cashew, oat, coconut, and soy substrates. Phosphorus content was measured via emission spectrometry by Eurofins (Madison, WI), and the phosphorus-to-protein ratio (PPR) was calculated for each PBY. RESULTS: Phosphorus content was highest in Silk Soy Strawberry, Silk Almond Strawberry, and Siggi's Coconut Mixed Berries, while it was lowest in So Delicious Coconut Strawberry, Oatly Oat Strawberry, Forager Cashew Strawberry, and Kite Hill Almond Strawberry. Ingredient labels revealed that Silk Soy Strawberry, Silk Almond Strawberry, and Oatly Oat Strawberry contained phosphorus additives, and Siggi's Coconut Mixed Berries contained pea protein additives. Though from the same substrate class, So Delicious Coconut Strawberry and Siggi's Coconut Mixed Berries showed significant differences in phosphorus and protein contents. All seven PBYs had higher PPR ratios than dairy yogurts like Stonyfield Organic Oikos Strawberry, Chobani Nonfat Strawberry, and Yoplait Greek Strawberry. CONCLUSION: Low-PPR foods are important for CKD patients. Siggi's Coconut Mixed Berries had the lowest PPR, making it potentially the most desirable for CKD patients. However, there is high variability in PPR among PBYs with the same substrate; therefore, Delicious Coconut Strawberry had the highest PPR, highlighting the importance of product selection for patients with CKD.
RESUMO
BACKGROUND: There is a lack of diversity in dermatology regarding skin of color-related content. This has negative implications for patients of color and continues to be a hurdle to providing proper care to these patient populations. As patients increasingly look to the internet as a resource to gain insight on dermatologic conditions and potential treatment options, the information presented must be accurate and informational. The goals of this study included identifying and analyzing skin of color-related dermatology content found on YouTube, characterizing the content creators, and comparing board-certified dermatologists’ content to that created by other YouTubers. METHODS: A total of 23 dermatology terms associated with skin of color were searched on YouTube. The top 9 relevant videos for each search term were analyzed for views, comments, likes, and content creator classification. Each video was also labeled as being promotional or educational. The content creator and the content subject were also analyzed. Content created by board-certified dermatologists as well as physicians was then compared to content created by non-physicians. Statistical comparison was done using Mann-Whitney U tests and Pearson’s Chi-squared test where appropriate. RESULTS: The most popular search term was dandruff while the least popular search terms were dermatosis papulose nigra, eczema, and central centrifugal cicatricial alopecia. Of the total 207 videos analyzed (Figure 1), the majority of video profiles consisted of medical interest groups (77, 37.2%), whereas the majority of video subjects consisted of board-certified dermatologists (50, 24.2%). In contrast, the least common video profiles belonged to patients (2, 1%), and the least common video subjects were news media (2, 1%). When comparing board-certified dermatologists to all other classifications of content creators, there was a significant difference in views, comments, and likes (views P=0.0477, comments P=0.0324, likes P=0.0203). When comparing all physicians to all other content creators, there was a similar trend (views P=0.0009, comments P<0.0001, likes P<0.0001). Physicians were significantly less likely to include promotional content in their videos when compared to other content creators (P=0.0170). CONCLUSION: Although skin of color-related dermatology content on YouTube is primarily educational, board-certified dermatologists are underrepresented as content creators on YouTube. It is pertinent that physicians continue to make content on YouTube and other social media platforms so that patients can have access to accurate yet salient information about their conditions. Patel J, Braswell AC, Jiminez VS, et al. Exploration of skin of color dermatology content on YouTube. J Drugs Dermatol. 2023;22(7):678-684. doi:10.36849/JDD.6995.
Assuntos
Dermatologia , Eczema , Mídias Sociais , Humanos , Pigmentação da Pele , Gravação em VídeoRESUMO
INTRODUCTION: Comorbidity trends after median sternectomy were studied at our institution by Vasconze et al (Comorbidity trends in patients requiring sternectomy and reconstruction. Ann Plast Surg. 2005;54:5). Although techniques for sternal reconstruction have remained unchanged, the patient population has become more complex in recent years. This study offers insight into changing trends in this patient population. METHODS: A retrospective review was performed of patients who underwent median sternectomy followed by flap reconstruction at out institution between 2005 and 2020. Comorbidities, reconstruction method, average laboratory values, and complications were analyzed. RESULTS: A total of 105 patients were identified. Comorbidities noted were diabetes (27%), immunosuppression (16%), hypertension (58%), renal insufficiency (23%), chronic obstructive pulmonary disease (16%), and tobacco utilization (24%). The most common reconstruction methods were omentum (45%) or pectoralis major flaps (34%). Thirty-day mortality rates were 10%, and presence of at least 1 complication was 34% (hematoma, seroma, osteomyelitis, dehiscence, wound infection, flap failure, and graft exposure). Univariate analysis demonstrated that sex (P = 0.048), renal insufficiency, surgical site complication, wound dehiscence, and flap failure (P < 0.05) had statistically significant associations with mortality. In addition, body mass index, creatinine, and albumin had a significant univariate association with mortality (P < 0.05). CONCLUSIONS: Similar to the original study, there is an association between renal insufficiency and mortality. However, the mortality rate is decreased to 10%, likely because of improved medical management of patients with increasing comorbidities (80% with greater than one comorbidity). This has led to the increased use of omentum as a first-line option. Subsequent wound dehiscence and flap failure demonstrate an association with mortality, suggesting that increasingly complex patients are requiring a method of reconstruction once used a last resort as a first-line option.
Assuntos
Procedimentos de Cirurgia Plástica , Insuficiência Renal , Comorbidade , Análise de Dados , Humanos , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/cirurgia , Procedimentos de Cirurgia Plástica/métodos , Insuficiência Renal/epidemiologia , Insuficiência Renal/cirurgia , Estudos Retrospectivos , Infecção da Ferida Cirúrgica/epidemiologia , Infecção da Ferida Cirúrgica/cirurgiaRESUMO
INTRODUCTION: Connecting patients with healthcare providers continues to grow as the digital era evolves. A successful website has the power to influence patients on choosing a practice and provider. The objectives of this study were to characterize information provided on private practice websites of plastics surgeons in the United States and to assess the relationship among the websites based on the number of years that the physicians have been in practice. METHODS: Newly board-certified plastic surgeons by the American Board of Plastic Surgery in 2005, 2010, and 2015 were identified. A Google search was conducted on all participants, and only those in private practice were included in this study. Each webpage was quantitatively and qualitatively assessed for the presence or absence of 23 criteria that were categorized as practice, physician, patient, or procedure information. χ2 was used for statistical analysis using Microsoft Excel (PSPP 1.2.0). A P value of less than 0.05 was considered statistically significant. RESULTS: Most plastic surgeons in each cohort were currently in private practice. A total of 532 plastic surgery private practice websites were analyzed. The data points found on 100% of the websites were directions to the facility and the contact for any billing questions. Most websites provided information on the practice and its surgeons. The most common web-based data points included online consultations and links to their social media. Information on expenses incurred by patients, such as cancellation policies and consultation fees, was least commonly listed. CONCLUSIONS: Our study shows that the number of years in practice is not associated with comprehensiveness of their website's content. This study provides insight into the content of plastic surgery private practices' websites in the United States in relation to the practice, the physician, the patient, and the procedures. This information may be useful for expanding and optimizing their websites. This has the potential to increase patient satisfaction and visibility of the practice. The success of these businesses is vital as the private sector in plastic surgery continues to grow.
Assuntos
Procedimentos de Cirurgia Plástica , Mídias Sociais , Cirurgiões , Cirurgia Plástica , Humanos , Internet , Prática Privada , Estados UnidosRESUMO
INTRODUCTION: Wound healing affects millions of people annually. After injury, keratinocytes from the wound edge proliferate, migrate, and differentiate to recapitulate the 3-dimensional (3D) structure needed to provide a barrier function. If the wound is too large, skin grafting may be required. We are interested in discovering novel strategies to enhance the wound healing process. It may be possible to recreate a viable and histologically accurate skin tissue using 3D printing. We hypothesize that keratinocytes and dermal fibroblasts can be bioprinted into a viable skin substitute. METHODS: Adult human dermal fibroblasts (HDFa) and adult human epidermal keratinocytes (HEKa) were cultured and subsequently printed with a 3D bioprinter within a hydrogel scaffold. After printing the HDFa and HEKa separately, cell viability and histological appearance were determined by sectioning the printed tissue and performing hematoxylin and eosin staining. The stained histological sections were analyzed for tissue morphology. RESULTS: The HEKa and HDFa cells suspended in the hydrogel were successfully printed into 3D scaffolds that resembled skin with hematoxylin and eosin staining. CONCLUSIONS: The HEKa and HDFa cells can be grown on 3D-printed hydrogels successfully. In addition, HEKa and HDFa cells can survive and grow when suspended in a hydrogel and 3D printed. Future potential applications of these results could lead to the creation of viable skin tissue for wound healing and surgical repair.
Assuntos
Pele Artificial , Células Cultivadas , Fibroblastos , Humanos , Queratinócitos , Impressão Tridimensional , Pele , Engenharia TecidualRESUMO
BACKGROUND: There is a paucity of research comparing journal articles that accrue numerous citations with those that accrue few citations over time. Understanding differences between journal articles can help direct investigators in designing and conducting their research. METHODS: Using advanced bibliometric tools, we queried four plastic surgery journals (Journal of Reconstructive Microsurgery, Annals of Plastic Surgery, Plastic and Reconstructive Surgery, and Microsurgery) for primary research articles published between 1998 and 2008 accruing zero or one citations with at least a 10-y lag time. Forty-seven articles were identified as low citation and were compared with an equal number of articles in the same journals that accrued the highest number of citations in the same period as high citation (HC). The data were analyzed using Student t-tests, Wilcoxon rank sum tests, chi-square tests, and Fisher exact tests. The level of significance was established at P < 0.05. RESULTS: When compared with the HC cohort, the low citation articles were more likely to be nonclinical (P < 0.001), have no plastic surgery authors (P = 0.0026), and focus on the field of microsurgery (P = 0.003). The HC cohort was more likely to have higher sample sizes (P = 0.0339), focus on aesthetic/cosmetic surgery (P = 0.003), have a higher number of other disciplines included on authorship (P < 0.001), references (P = 0.0451), manuscript pages (P < 0.001), and words in the abstract (P < 0.001). CONCLUSIONS: A small number of articles published in four plastic surgery journals were uncited during a 10-y period. There are qualitative and quantitative differences between highly and lowly cited articles in the plastic surgery literature. Investigators should consider these differences when designing and conducting studies.
Assuntos
Bibliometria , Pesquisa Biomédica/estatística & dados numéricos , Publicações/estatística & dados numéricos , Cirurgia Plástica/estatística & dados numéricos , Projetos de PesquisaRESUMO
BACKGROUND: This systematic review identified published studies that evaluated the use of pro re nata (PRN) medication in patients with acute agitation or aggression of undifferentiated etiology. METHODS: A literature search was conducted of PubMed and MEDLINE for randomized controlled trials (RCTs) that evaluated the use of PRN medications for individuals with undifferentiated agitation or aggression. Bibliographic databases of published articles were also searched for additional studies. RESULTS: A total of 15 studies were identified that assessed the effects of first-generation antipsychotics (FGAs), second-generation antipsychotics (SGAs), benzodiazepines, and combination therapies. All RCTs showed variable degrees of sedation and decreased agitation over time with the use of these medications, as well as variable levels of adverse events. CONCLUSIONS: Evidence exists to support the use of specific SGAs as firstline PRN medications in the management of acutely agitated individuals. While evidence exists to support the use of FGAs, benzodiazepines, and combination therapy, efficacy is similar for each class, and SGAs appear to have the most favorable adverse effect profile.
Assuntos
Agressão/efeitos dos fármacos , Tratamento Farmacológico , Ensaios Clínicos Controlados Aleatórios como Assunto , HumanosRESUMO
Brain accumulation of soluble oligomers of the amyloid-ß peptide (AßOs) is increasingly considered a key early event in the pathogenesis of Alzheimer's disease (AD). A variety of AßO species have been identified, both in vitro and in vivo, ranging from dimers to 24mers and higher order oligomers. However, there is no consensus in the literature regarding which AßO species are most germane to AD pathogenesis. Antibodies capable of specifically recognizing defined subpopulations of AßOs would be a valuable asset in the identification, isolation, and characterization of AD-relevant AßO species. Here, we report the characterization of a human single chain antibody fragment (scFv) denoted NUsc1, one of a number of scFvs we have identified that stringently distinguish AßOs from both monomeric and fibrillar Aß. NUsc1 readily detected AßOs previously bound to dendrites in cultured hippocampal neurons. In addition, NUsc1 blocked AßO binding and reduced AßO-induced neuronal oxidative stress and tau hyperphosphorylation in cultured neurons. NUsc1 further distinguished brain extracts from AD-transgenic mice from wild type (WT) mice, and detected endogenous AßOs in fixed AD brain tissue and AD brain extracts. Biochemical analyses indicated that NUsc1 targets a subpopulation of AßOs with apparent molecular mass greater than 50 kDa. Results indicate that NUsc1 targets a particular AßO species relevant to AD pathogenesis, and suggest that NUsc1 may constitute an effective tool for AD diagnostics and therapeutics.
RESUMO
INTRODUCTION: Dislocation is a potentially devastating complication severely affecting outcomes post total hip arthroplasty (THR). We aimed to assess the efficacy and safety of closed reduction of a dislocated THR within the Emergency Department (ED). METHODS: A prospective multi-centre study was conducted over a 1-year period from November 2020 to December 2021 within 10 hospitals based in the East of England. Collected data included patient demographics, agent used for sedation, hospital length of stay, implant type and discharge destination. Patients were analysed according to whether successful reduction was performed in the ED or not. The primary outcome was length of stay, with secondary outcomes including discharge destination and pain post-procedure. RESULTS: We studied 99 patients with an average age of 77.02 years, with 39 (39%) patients being male. 11 patients had revision hip replacements and 88 patients had primary THRs. 57 (57.6%) underwent closed reduction in the Emergency department, of which 44 (77.2%) were successful. Successful closed reduction was significantly associated with lower patient age (p = 0.02), lower American society of Anesthesiologists (ASA) score (p < 0.01) and use of propofol (p < 0.01). Patients who underwent successful ED closed reduction had a lower hospital stay than those that did not (1 vs. 3 days, p < 0.01), however there was no significant difference in discharge destination. CONCLUSIONS: When adopted, success following closed reduction is increased in younger patients with less comorbidities following use of propofol sedation. Following sedation, patients have a significantly shorter hospital stay. Increasing uptake of closed reduction of THR dislocation within the ED in suitable patients with evidence-based best practice protocols will maximise patient outcomes whilst allowing efficient resource utilisation.
RESUMO
The ketogenic diet is a very low carbohydrate diet that has received a lot of attention for its role in the treatment of type 2 diabetes and obesity. For patients with chronic kidney disease, there is limited evidence on the risks and/or benefits of this diet. However, from the limited evidence that does exist, there are several inferences that can be drawn regarding this diet for patients with kidney disease. The ketogenic diet may not be better than comparator higher carbohydrate diets over the long term. The diet also has low adherence levels in studies lasting ≥12 months. The diet's emphasis on fat, which often comes from animal fat, increases the consumption of saturated fat, which may increase the risk of heart disease. It has the potential to worsen metabolic acidosis by increasing dietary acid load and endogenous acid production through the oxidation of fatty acids. In addition, the diet has been associated with an increased risk of kidney stones in patients using it for the treatment of refractory epilepsy. For these reasons, and for the lack of safety data on it, it is reasonable for patients with kidney disease to avoid utilizing the ketogenic diet as a first-line option given alternative dietary patterns (like the plant-dominant diet) with less theoretical risk for harm. For those adopting the ketogenic diet in kidney disease, a plant-based version of the ketogenic diet may mitigate some of the concerns with animal-based versions of the ketogenic diet.
RESUMO
Although St-Jules et al have presented the case for postprandial hyperkalemia with food, including plant foods, there (still) is little to no direct evidence supporting the occurrence of postprandial hyperkalemia, mostly due to a lack of studies performed exclusively using food. Food is different than salts or supplements, and it is likely that a banana behaves differently than potassium salts. A growing body of evidence supports the use of plant foods without causing hyperkalemia in patients with kidney disease. Currently, only 1 study has reported on the postprandial effects of hyperkalemia. In this study, there was a substantial reduction in the instances of postprandial hyperkalemia in participants consuming a diet that included more plant foods and more fiber. At the time of this writing, there is no evidence to support risk or safety of certain foods with regard to postprandial hyperkalemia, and additional research is warranted.
RESUMO
Low-protein diets (LPDs), usually defined as a daily dietary protein intake of 0.6 to 0.8 g/kg body weight, have been recommended for decades as a safe and effective lifestyle modification to ameliorate inflammatory damage and proteinuria, reduce glomerular hyperfiltration, and improve metabolic acidosis control in patients with chronic kidney disease (CKD). The mechanism for this is largely attributed to altered tubuloglomerular feedback and afferent arteriole contraction leading to decreased glomerular pressure. Additionally, low protein intake reduces urea generation, which can help delay dialysis initiation in advanced CKD. LPDs have different types including plant-dominant LPDs that can exert additional kidney protective effects as a result of dietary protein quality in addition to quantity. In addition, strong clinical evidence shows that a new class of diabetes mellitus medications, the sodium-glucose cotransporter 2 inhibitors, reduces albuminuria and slows the estimated glomerular filtration rate decline in CKD, even in patients without diabetes mellitus, especially if significant proteinuria is present. Given prior studies investigating the effect of LPDs used in conjunction with angiotensin pathway modulators, we argue that LPDs have a synergistic role in disease management and are expected to display additive effects when combined with sodium-glucose cotransporter 2 inhibitor usage or other pharmacologic agents. Even with medical therapy, it is prudent to implement tailored LPDs for different types of CKD.
Assuntos
Diabetes Mellitus , Insuficiência Renal Crônica , Inibidores do Transportador 2 de Sódio-Glicose , Humanos , Inibidores do Transportador 2 de Sódio-Glicose/farmacologia , Dieta com Restrição de Proteínas , Proteínas Alimentares , Diálise Renal , Insuficiência Renal Crônica/tratamento farmacológico , Proteinúria/tratamento farmacológico , Glucose , SódioRESUMO
Immunoglobulin A nephropathy is the most common glomerulonephritis syndrome in the world, yet there is currently no cure. While blood pressure control, renin-angiotensin-aldosterone system inhibition, and immunosuppression may slow disease progression, low-protein diets, defined as a daily dietary protein intake of 0.6 to 0.8 g/kg body weight, may also decrease immune complex deposition and disease severity, as evidenced in animal models. The link between secondary immunoglobulin A nephropathy and celiac disease has also led to the rise of gluten-free diets and zinc supplementation as potential lifestyle modifications to help manage common immunoglobulin A nephropathy symptoms such as proteinuria and hematuria. In addition, case reports and prospective studies suggest that patients with focal segmental glomerulosclerosis, which manifests as steroid-resistant nephrotic syndrome may also benefit from a gluten-free diet. We highlight the example of a gluten-free, plant-dominant low-protein diet (a different type of low-protein diet that addresses both protein quantity and quality) for patients with immunoglobulin A nephropathy or focal segmental glomerulosclerosis.
Assuntos
Glomerulonefrite por IGA , Glomerulosclerose Segmentar e Focal , Animais , Humanos , Glomerulosclerose Segmentar e Focal/complicações , Glomerulonefrite por IGA/complicações , Dieta com Restrição de Proteínas/efeitos adversos , Dieta Livre de Glúten , Estudos Prospectivos , Proteínas Alimentares , Proteínas de PlantasRESUMO
Although both private practices and academic institutions in dermatology treat the same variety of pathologies, private practices entice more patients. The purpose of this study was to examine the differences in website content between dermatology private practices and academic institutions. All 140 dermatology residency programs were first queried. Only websites that contained pertinent information for patients were used in this study (113 of 140 programs). A total of 113 private practice websites were then matched for location and reputation. These sites were assessed for 23 content criteria categorized as practice, physician, patient, or treatment/procedure. The results may be useful for optimizing both private practice and academic institution websites so that patients can better understand the institutions that provide their care.
Assuntos
Dermatologia , Médicos , Prática Privada , Humanos , InternetRESUMO
COVID-19 has had a significant impact on patient health and the delivery of healthcare within the UK. This article highlights perioperative considerations as elective work moves back to pre-pandemic levels.
Assuntos
COVID-19 , Atenção à Saúde , Procedimentos Cirúrgicos Eletivos , Humanos , Pandemias/prevenção & controleRESUMO
Introduction A large proportion of the United States' underinsured population relies on free health clinics for their health care needs. With only a few free health clinics nationwide hosting specialty clinics, a small subset of which are dermatology clinics, there is a dearth of information in the literature on which dermatological pathologies and treatment modalities are most common in this setting. The purpose of this study was to establish the most common dermatological conditions and treatments in the free health care setting as well as understand which facets of care need improvement. Methods A total of 57 patients with dermatological findings were identified at an urban student-run free health clinic in the southern United States in the past two years (2019-2021). Information reviewed for each patient included general demographics, chief complaint, medical/surgical history, treatments/procedures required for each visit, treatments/procedures available for each visit, referrals, and follow-up rate. Qualitative analysis was performed. Results The median age of the patients that presented with dermatological findings was 40 while the most common ethnicities were white (26.2%), Hispanic/Latino (28.6%), and black (28.6%). The most common chief complaints were rashes and cysts with a majority (63.2%) of these patients presenting to this particular clinic for the first time. Seven patients (12.3%) were unable to receive treatment due to expense, procedure unavailability, or an unknown reason. The most common treatment prescribed included a topical steroid. A majority (71.9%) of the patients were unable to follow up as scheduled. A majority of patients (81.2%) that were able to follow up were adherent to their prescribed medication. Conclusion Although dermatological conditions are plentiful in the free health care setting, the literature currently contains no information regarding this topic. This may be due to low patient follow-up rates and inadequately charted outcomes on often outdated electronic health records. In order to best care for dermatology patients in this setting, it is necessary to understand the barriers to care and available treatment options.
RESUMO
We studied the interactions of the CO(2)-concentrating mechanism and variable light in the filamentous cyanobacterium Leptolyngbya sp. CPCC 696 acclimated to low light (15 µmol m(-2) s(-1) PPFD) and low inorganic carbon (50 µM Ci). Mass spectrometric and polarographic analysis revealed that mediated CO(2) uptake along with both active Na(+)-independent and Na(+)-dependent HCO(3)(-) transport, likely through Na(+)/HCO(3)(-) symport, were employed to concentrate Ci internally. Combined transport of CO(2) and HCO(3)(-) required about 30 kJ mol(-1) of energy from photosynthetic electron transport to support an intracellular Ci accumulation 550-fold greater than the external Ci. Initially, Leptolyngbya rapidly induced oxygen evolution and Ci transport to reach 40-50% of maximum values by 50 µmol m(-2) s(-1) PPFD. Thereafter, photosynthesis and Ci transport increased gradually to saturation around 1,800 µmol m(-2) s(-1) PPFD. Leptolyngbya showed a low intrinsic susceptibility to photoinhibition of oxygen evolution up to PPFD of 3,000 µmol m(-2) s(-1). Intracellular Ci accumulation showed a lag under low light but then peaked at about 500 µmol photons m(-2) s(-1) and remained high thereafter. Ci influx was accompanied by a simultaneous, light-dependent, outward flux of CO(2) and by internal CO(2)/HCO(3)(-) cycling. The high-affinity and high-capacity CCM of Leptolyngbya responded dynamically to fluctuating PPFD and used excitation energy in excess of the needs of CO(2) fixation by increasing Ci transport, accumulation and Ci cycling. This capacity may allow Leptolyngbya to tolerate periodic exposure to excess high light by consuming electron equivalents and keeping PSII open.
Assuntos
Bicarbonatos/metabolismo , Dióxido de Carbono/metabolismo , Carbono/metabolismo , Cianobactérias/fisiologia , Cianobactérias/efeitos da radiação , Fotossíntese/efeitos da radiação , Aclimatação/efeitos dos fármacos , Aclimatação/efeitos da radiação , Transporte Biológico/efeitos dos fármacos , Transporte Biológico/efeitos da radiação , Isótopos de Carbono/análise , Cloratos/farmacologia , Clorofila/metabolismo , Clorofila A , Cianobactérias/efeitos dos fármacos , Cianobactérias/isolamento & purificação , DNA Ribossômico/química , DNA Ribossômico/genética , Luz , Fotossíntese/efeitos dos fármacos , Complexo de Proteína do Fotossistema II/efeitos dos fármacos , Complexo de Proteína do Fotossistema II/efeitos da radiação , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Fatores de TempoRESUMO
INTRODUCTION: An estimation of pretest probability is integral to the proper interpretation of a negative compression ultrasound in the diagnostic assessment of lower-extremity deep vein thrombosis. We sought to determine the rate, method, and predictors of pretest probability estimation in such patients. METHODS: This cross-sectional study of outpatients was conducted in a suburban community hospital in 2006. Estimation of pretest probability was done by enzyme-linked immunosorbent assay d-dimer, Wells criteria, and unstructured clinical impression. Using logistic regression analysis, we measured predictors of documented risk assessment. A cohort analysis was undertaken to compare 3-month thromboembolic outcomes between risk groups. RESULTS: Among 524 cases, 289 (55.2%) underwent pretest probability estimation using the following methods: enzyme-linked immunosorbent assay d-dimer (228; 43.5%), clinical impression (106; 20.2%), and Wells criteria (24; 4.6%), with 69 (13.2%) patients undergoing a combination of at least two methods. Patient factors were not predictive of pretest probability estimation, but the specialty of the clinician was predictive; emergency physicians (P < .0001) and specialty clinicians (P = .001) were less likely than primary care clinicians to perform risk assessment. Thromboembolic events within 3 months were experienced by 0 of 52 patients in the explicitly low-risk group, 4 (1.8%) of 219 in the explicitly moderate- to high-risk group, and 1 (0.4%) of 226 in the group that did not undergo explicit risk assessment. CONCLUSIONS: Negative ultrasounds in the workup of deep vein thrombosis are commonly interpreted in isolation apart from pretest probability estimations. Risk assessments varied by physician specialties. Opportunities exist for improvement in the diagnostic evaluation of these patients.