Tourniquet Use in Extremity-Based Microsurgery.

BACKGROUND: The use of tourniquets and their role in extremity-based microsurgery has not been thoroughly investigated. The purpose of this study was to investigate tourniquet use and its associated outcomes and complications. The authors hypothesize that tourniquets enhance visualization, bloodless approaches to vessel harvest, flap elevation, and anastomosis without added complications. METHODS: A retrospective chart review was completed for patients who had undergone extremity-based microsurgery with the use of a tourniquet between January 2018 and February 2022 at two large academic institutions. Demographic characteristics, initial reasons for surgery, complications, and outcomes were recorded. Patients were separated into groups based on tourniquet use during three operative segments: (1) flap elevation, (2) vessel harvest, and (3) microvascular anastomosis. An internal comparison of complication rate was performed between cases for which a tourniquet was used for one operative segment to all cases in which it was not used for the same operative segment. Univariate and multivariate statistical analyses were performed to identify statistically significant results. RESULTS: A total of 99 patients (106 surgeries) were included in this study across sites. The mean age was 41.2 years and 67.7% of the patients were male. The most common reason for microsurgical reconstruction was trauma (50.5%). The need for an additional unplanned surgery was the most common surgical complication (16%). A total of 70, 61, and 32% of procedures used a tourniquet for flap elevation, vessel harvest, and for anastomosis, respectively. Statistical analyses identified no difference in complication rates for procedures for which a tourniquet was or was not used for interventions. CONCLUSION: Based on these results, the authors state that tourniquets can be utilized for extremity-based microsurgery to enable bloodless dissection without the concern of increased complication rates.

Developing and deploying deep learning models in brain magnetic resonance imaging: A review.

Magnetic resonance imaging (MRI) of the brain has benefited from deep learning (DL) to alleviate the burden on radiologists and MR technologists, and improve throughput. The easy accessibility of DL tools has resulted in a rapid increase of DL models and subsequent peer-reviewed publications. However, the rate of deployment in clinical settings is low. Therefore, this review attempts to bring together the ideas from data collection to deployment in the clinic, building on the guidelines and principles that accreditation agencies have espoused. We introduce the need for and the role of DL to deliver accessible MRI. This is followed by a brief review of DL examples in the context of neuropathologies. Based on these studies and others, we collate the prerequisites to develop and deploy DL models for brain MRI. We then delve into the guiding principles to develop good machine learning practices in the context of neuroimaging, with a focus on explainability. A checklist based on the United States Food and Drug Administration's good machine learning practices is provided as a summary of these guidelines. Finally, we review the current challenges and future opportunities in DL for brain MRI.

Negative pressure wound therapy on complex extremity wounds requiring coverage with a meshed bilayer wound matrix: a retrospective analysis.

OBJECTIVE: The treatment of complex extremity wounds is technically challenging. In this 5-year retrospective review, we compared the use of Integra Meshed Bilayer Wound Matrix (IMBWM; Integra LifeSciences, US) followed by a split-thickness skin graft (STSG) combined with negative pressure wound therapy (NPWT) versus IMBWM followed by STSG alone for the management of these wounds. METHOD: Data from patients undergoing management using IMBWM for a complex extremity wound coverage were collected. RESULTS: Among the 109 patients studied, the wounds of 62 patients were managed using IMBWM and NPWT, and 47 were managed using IMBWM alone. The most common aetiology of these injuries was trauma. Wound size and location were similar for each group, ranging in size from 2-30cm2 and being primarily on the forearm, followed by the leg and arm. There was a significantly greater take of the IMBWM+STSG with NPWT (96.8%) compared to without NPWT (85.1%, p=0.03). There were significantly fewer reapplications of the dermal matrix required in the NPWT group (3.2%) versus the non-NPWT group (14.9%, p=0.03). There were significantly fewer postoperative complications, prior to STSG, in the NPWT group (3.2%) versus the non-NPWT group (14.9%, p=0.03). CONCLUSION: The combination of IMBWM with NPWT leads to a higher success rate, and can reduce the number of dermal matrix reapplications and postoperative complications, in the setting of complex extremity wounds. The use of IMBWM in combination with NPWT has the potential to improve both surgical procedures and patient outcomes in this setting.

[Implementation of a fracture liaison service. Experience with 177 patients]. / No Más Fracturas - Implementación de la primera Unidad de Coordinación de Fracturas en Chile: experiencia al año de funcionamiento.

BACKGROUND: Every year about 9 million fragility fractures (FF) occur worldwide and 80% of these are underdiagnosed or undertreated. Aiming to close the gap of diagnosis and treatment of osteoporosis, Fracture Liaison Services (FLS) were developed. AIM: To describe the implementation of the first FLS in Chile, its inclusion criteria, patient enrolment, treatment adherence and referrals during the first year. MATERIAL AND METHODS: A FLS was implemented at a health care network composed by two hospitals. The International Osteoporosis Foundation (IOF) guidelines were applied with a nurse practitioner as the coordinator. From May 2020 to April 2021 all patients diagnosed with a FF in the emergency rooms were invited to participate. Patients with pathological fractures and active cancer were excluded. Demographical data, fracture location, previous fractures, treatment and adherence, and mortality were recorded. RESULTS: From 443 patients with a diagnosis of FF, 177 patients (40%) accepted to participate. Their mean age was 74 ± 13 years and 84% (149) were female. Forty eight percent (84) had a lower extremity FF. Hip fractures were the most common (67). Ninety-five patients reported previous FF and 11,2% (20) had received anti-osteoporotic treatment. At four months of follow-up, 62% (50) had received vitamin D and calcium supplementation and 20% (16) of those patients with an indication of anti-osteoporotic drugs, had received them. CONCLUSIONS: The implementation of the FLS was successful with a 40% enrolment of patients, receiving certification by the IOF.

Distribution and ecological risk of metals in an urban natural protected area in the Riviera Maya, Mexico.

Urbanization can negatively impact natural protected areas near or surrounded by cities, and such impacts include untreated wastewater discharge, leachates from dumpsters, e-waste, and road dust. In this research, we show that not only large cities with industry are prone to be polluted, but also young touristic cities with high population increase rate can suffer from urban contamination. We evaluated metal pollution in a natural protected area within a 50-year-old city without conventional industry that was likely contaminated by the urban sprawl around the protected area. We tested water, zooplankton, sediment and plant samples for metallic elements to evaluate their bioaccumulation in zooplankton, enrichment factors and geoaccumulation index values in sediments, and translocation factors in plants. Finally, we evaluated the ecological risk due to metal contamination. Metals at levels above our detection limit (20 µg/L) were not found in the water and zooplankton samples. The sediments and plants in the storm drain section of the protected area had a greater concentration of metals and wastewater indicators (coliforms) than those in the rest of the lagoon. Moreover, signs of Al, Cu, Ni, Zn, Cr, Pb, and Ti contamination were found in the plant tissues. We estimated that the ecological risk of this natural protected area surrounded by the city of Cancun (Mexico) ranged from mild to strong, with Zn being the metal of most concern. The results highlight that young touristic cities around the world will endure contamination from urban sources; signs or early warnings of contamination must be identified to prevent and resolve such issues.

Cost Analysis and National Trends in the Treatment of Dupuytren Contracture Comparing Collagenase Injection, Needle Fasciotomy, and Open Fasciectomy Procedures.

BACKGROUND: Dupuytren contracture (DC) is a common disorder characterized by progressive fibrosis of palmar fascia. This study analyzed cost trends of 3 common treatments for DC: fasciotomy, fasciectomy, and collagenase injection (CI)/cord manipulation. METHODS: The Vizient Clinical Data/Resource Manager electronic database was reviewed for all procedures for the treatment of DC at participating hospitals in the United States (US) from October 1, 2015, to September 1, 2019. Cases were placed into 1 of 3 categories: (1) CI, (2) needle fasciotomy (NF), and (3) open fasciectomy (OF). Total and direct costs were averaged for each procedure and compared nationally and regionally. Temporal trends and specific market share were analyzed. One-tailed t test and Pearson correlation analysis was performed (P < 0.05 and r > 0.9 or r < -0.9 was considered significant). RESULTS: A total of 22,974 total cases were identified. A total of 16,966 OF, 3962 NF, and 2046 CI were performed. There was a nearly a 4-fold increase in number of procedures to treat DC from 2015 to 2018. Market share percentage of each procedure stayed relatively similar over time. However, market share percentage differed between procedures. Needle fasciotomy had the lowest market share percentage approximately 7%. Collagenase injection had the highest average cost at US $4453.66 and was significantly higher than OF at US $3394.90 and NF at US $2010.75. Cost and distribution of procedures were further analyzed by geographic regions. In 2018, 32% of procedures performed were in the Northeastern US, 29% in the Midwestern US, 23% in the Southern US, and 16% in the Western US. Total number of Dupuytren procedures increased more than 300% in all regions across the US from 2015 to 2018. In every region, NF was the lowest cost intervention. Cost of OF and CI varied between regions and was often the most expensive intervention. CONCLUSIONS: Treatment of DCs with NF seems to be the least costly treatment option. Needle fasciotomy seems to be the least commonly performed procedure. Regional data show variations in the cost of OF and CI. However, OF has the majority market share nationally and regionally. Although the cost of these procedures seems to vary regionally, the type of procedures being performed seem to be similar across regions.

Practice Patterns Among Hand Surgeons According to Primary Residency Training: A National Surgical Quality Improvement Project Study.

INTRODUCTION: Hand surgery fellowships accept applicants from 3 different residencies: general surgery, orthopedic surgery, and plastic surgery. Although all of these specialties culminate into a board-certified hand surgeon, each specialty receives drastically different training in residency, which can have effects on which procedures these surgeons feel comfortable performing in their own practices. This study aims to compare practice patterns and complication rates among hand surgeons by residency training. METHODS: The National Surgical Quality Improvement Program database was queried between the years of 2014 and 2018 for all Current Procedural Terminology codes pertaining to upper-extremity surgical procedures performed below the elbow. Procedures not performed by a general, orthopedic, or plastic surgeon were excluded, as well as polytraumas. Procedures were then stratified by anatomic region, tissue type, and primary specialty of the attending surgeon. Data collected included the number of each procedure, patient complexity, and complications. Statistical analysis consisted of a t test for continuous variables, χ2 analysis for categorical variables, and linear regression analysis to compare complications rates between specialties. RESULTS: A total of 76,980 unique cases were included in our analysis: 4979 (6.4%) at the elbow, 43,680 (56.7%) at the forearm/wrist, 23,284 (30.2%) at the hand, 1421 (1.8%) flaps/grafts, 285 (0.4%) vascular, and 3331 (4.3%) neurological. Orthopedics performed most (79.5%) of the procedures, whereas plastic surgeons and general surgeons performed 17.3% and 3.1%, respectively. There were also significant differences by anatomic location/type of procedure, with orthopedic surgeons performing 99.2% of procedures at the elbow but only 67.7% of procedures at the hand. Linear regression analysis showed general surgeons had the lowest complication rates. CONCLUSIONS: Our data show significant differences in the number of upper-extremity surgeries performed by surgeons from each specialty at different anatomic locations.This could be due to differences in training during residency or proportionately more orthopedic surgeons being "full-time" hand surgeons. These data could affect hiring patterns in hospitals seeking hand surgeons depending on the variety of pathology encountered at that particular institution.

Analgesic effect of postoperative laparoscopic-guided transversus abdominis plane (TAP) block, associated with preoperative port-site infiltration, within an enhanced recovery after surgery protocol in one-anastomosis gastric bypass: a randomized clinical trial.

BACKGROUND: The use of ultrasonography to assist needle placement during transverse abdominal plane (TAP) technique has provided direct visualization of surround anatomical musculature and facial planes. However, the increased girth in patients undergoing bariatric surgery is challenging to visualize via ultrasonography which may lead to poor postoperative analgesia. OBJECTIVE: The aim of the study is to investigate whether the addition of postoperative laparoscopic-guided TAP block as part of a multimodal analgesic regimen within the ERAS protocol compared to no block provides better postoperative analgesia in patients undergoing one-anastomosis gastric bypass surgery. PATIENTS AND METHODS: A prospective clinical trial was performed. Patients were randomized into two groups: patients undergoing postoperative laparoscopic-guided TAP (TAP-lap) and patients not receiving TAP-lap (Control). Multimodal analgesia included preoperative port-site infiltration with Bupivacaine 0.25% in both groups and systemic Acetaminophen. Pain quantification as measured by visual analogic scale (VAS) was assessed at 6 and 24 h after surgery, and 24-h postoperative opioid consumption. RESULTS: One hundred and forty patients were included, 70 in each group. The mean operation time was 78.5 ± 14.4 min in TAP-lap and 75.9 ± 15.6 min in Control (NS). The mean postoperative pain, as measured by VAS, 6 h after surgery was 23.1 ± 11.3 mm in TAP-lap and 41.8 ± 16.2 mm in Control (p = 0.001). 24 h after surgery was 16.6 ± 11.4 mm in TAP-lap and 35.4 ± 12.7 mm in Control (p = 0.001). Morphine rescues were necessary in 14.2% in Control and 2.8% in TAP-lap (p = 0.035). CONCLUSION: Laparoscopic-guided TAP block as part of a multimodal analgesia regimen can reduce postoperative pain and opioid consumption, without increasing operative time.

Axon Injury-Induced Autophagy Activation Is Impaired in a C. elegans Model of Tauopathy.

Autophagy is a conserved pathway that plays a key role in cell homeostasis in normal settings, as well as abnormal and stress conditions. Autophagy dysfunction is found in various neurodegenerative diseases, although it remains unclear whether autophagy impairment is a contributor or consequence of neurodegeneration. Axonal injury is an acute neuronal stress that triggers autophagic responses in an age-dependent manner. In this study, we investigate the injury-triggered autophagy response in a C. elegans model of tauopathy. We found that transgenic expression of pro-aggregant Tau, but not the anti-aggregant Tau, abolished axon injury-induced autophagy activation, resulting in a reduced axon regeneration capacity. Furthermore, axonal trafficking of autophagic vesicles were significantly reduced in the animals expressing pro-aggregant F3ΔK280 Tau, indicating that Tau aggregation impairs autophagy regulation. Importantly, the reduced number of total or trafficking autophagic vesicles in the tauopathy model was not restored by the autophagy activator rapamycin. Loss of PTL-1, the sole Tau homologue in C. elegans, also led to impaired injury-induced autophagy activation, but with an increased basal level of autophagic vesicles. Therefore, we have demonstrated that Tau aggregation as well as Tau depletion both lead to disruption of injury-induced autophagy responses, suggesting that aberrant protein aggregation or microtubule dysfunction can modulate autophagy regulation in neurons after injury.

Vitamin D and Bone Mineral Density in HIV Newly Diagnosed Therapy-Naive Patients Without Any Secondary Causes of Osteoporosis.

Bone loss and vitamin D deficiency are common in HIV patients. However, bone health status in newly diagnosed HIV patients has not been thoroughly described. Our aim was to assess the bone mineral density (BMD), bone resorption and vitamin D status in newly diagnosed HIV patients. A prospective observational study in HIV newly diagnosed therapy-naive persons. Patients with secondary causes of osteoporosis were excluded. Bone densitometry (DXA), a bone resorption marker (CTx), 25-hydroxyvitamin D (25OHD), CD4 count and HIV viral load (VL) were done in 70 patients. Vitamin D results were compared with a group of healthy volunteers. All patients were men, mean age 31 years (19-50). Low BMD (Z score ≤ 2.0) was found in 13%, all of them in lumbar spine, and in only one patient also in femoral neck. Bone resorption was high in 16%. One out of four participants had low BMD or high bone resorption. Vitamin D deficiency (25OHD < 20 ng/mL) was found in 66%. Mean 25OHD in patients was significantly lower than in healthy volunteers (p = 0.04). No associations were found between BMD, CTx, 25OHD and VL or CD4 count. We hypothesize that HIV infection negatively affects bone health based on the results we found among newly diagnosed, therapy-naive, HIV-infected patients, without any known secondary causes of osteoporosis. Low BMD or high bone resorption, are significantly prevalent in these patients. HIV-infected patients had a higher prevalence of vitamin D deficiency than controls, which was not correlated with CD4 count or VL.

Long-term follow-up after sleeve gastrectomy versus Roux-en-Y gastric bypass versus one-anastomosis gastric bypass: a prospective randomized comparative study of weight loss and remission of comorbidities.

BACKGROUND: One-Anastomosis Gastric Bypass (OAGB) has exponentially increased in the last decade, as it is associated with very low complications, mortality, readmissions and reoperations rates, and shows excellent short- and long-term benefits of weight loss and resolution of comorbidities. The aim of this study was to compare the effect of SG, RYGB, and OAGB, on short- and long-term weight loss and comorbidities resolution. METHODS: A prospective randomized clinical study of all morbidly obese patients undergoing SG, RYGB, and OAGB, as primary bariatric procedures, was performed. Patients were randomly assigned into 3 groups: those patients undergoing SG, those ones undergoing RYGB and those ones undergoing OAGB. BMI, excess BMI loss (EBMIL) and remission of type 2 diabetes (T2DM), hypertension (HT), and dyslipidemia (DL) were assessed. RESULTS: 600 patients were included in the study, 200 in each group. Follow-up rate at 5 years postoperatively was 91% in SG group, 92% in RYGB, and 90% in OAGB. OAGB achieves significantly greater EBMIL than RYGB and SG at 1, 2, and 5 years (p < 0.001, respectively). At 5 years, OAGB achieves significantly greater remission of T2DM (p = 0.027), HT (p = 0.006), and DL (p < 0.001) than RYGB and SG. RYGB did not show significant superiority than SG in short- and long-term remission of T2DM and HT, but achieves greater remission of DL (p < 0.001). CONCLUSION: OAGB achieves superior mid- and long-term weight loss than RYGB and SG. There are no significant differences in weight loss between SG and RYGB at 1, 2, and 5 years. OAGB achieves better short- and long-term resolution rates of DM, HT, and DL than SG and RYGB. RYGB and SG obtain similar T2DM and HT remissions, but RYGB reaches significantly greater rates of DL remission. ClinicalTrials.gov Identifier: NCT03467646.

Use of DNA sequencing for noncommunicable diseases in low-income and middle-income countries' primary care settings: A narrative synthesis.

OBJECTIVE: To present a systematic narrative review, informed by international experience, on the use of genomic analysis technologies in the primary care of noncommunicable chronic diseases (NCDs) during the last 20 years. METHODS: We used the methodology for conducting systematic reviews proposed by the Center for Coordination and Information on Evidence for Policies and Practices. The selected articles were organized by time, place, study design, and type of DNA sequencing. Finally, we analyzed the implications of our findings for health systems in middle-income and low-income countries focusing on a NCD high prevalence country such as México. RESULTS: Evidence concerning the use of DNA sequencing in primary care for NCDs was scarce and geographically concentrated in high-income countries. Use was limited by costs, insufficient knowledge among health care personnel, and a lack of confidence on the part of users. CONCLUSIONS: The use of DNA sequencing for primary care of NCDs is a challenge for low- and middle-income countries. More evidence is needed on cost effectiveness, public funding mechanisms, and the training of health care personnel for its implementation.

[Pseudohypoparathyroidism: report of two cases of late presentation]. / Pseudohipoparatiroidismo de presentación tardía: reporte de dos casos.

Pseudohypoparathyroidism (PHP) is a group of rare genetic disorders that share organ targeted resistance to the action of parathyroid hormone (PTH) as a common feature. Biochemically, they may present with hypocalcemia, hyperphosphatemia and elevated PTH. Some forms present with a specific phenotype: short stature, round facies, short neck, obesity, brachydactyly and subcutaneous calcifications, called Albrigth's Hereditary Osteodystrophy (AHO). This spectrum of disorders are caused by several alterations in the gene coding for the alpha subunit of the G protein (GNAS): an ubiquitous signaling protein that mediates the action of numerous hormones such as PTH, TSH, gonadotropins, and ACTH, among others. According to their inheritance with maternal or paternal imprinting, they may manifest in a diversity of clinical forms. Although most commonly diagnosed during childhood, PHP may manifest clinically during adolescence or early adulthood. We report two late presenting cases of pseudohypoparathyroidism. A 21-year-old female with biochemical abnormalities characteristic of pseudohypoparathyroidism who was misdiagnosed as epilepsy and a 13-year-old boy with the classic AHO phenotype but without alterations in phospho-calcium metabolism, compatible with pseudopseudohypoparathyrodism.

[Guidelines of the Chilean Endocrinology Society for the correct clinical use of bone densitometry]. / Recomendaciones para el uso correcto de densitometría ósea en la práctica clínica. Consenso de la Sociedad Chilena de Endocrinología y Diabetes.

Osteoporosis is a silent and frequent disease, which increases fracture risk. Approximately half of women and one of five men over 50 years old will suffer an osteoporotic fracture throughout their lives. Dual-energy x-ray absorptiometry (DXA) allows a real bone mineral density (BMD) measurement in different parts of the skeleton and is considered the "gold standard" for quantifying osteoporosis with high accuracy and precision. The Board of the Chilean Society of Endocrinology and Diabetes (SOCHED) required from the Bone Disease Study Group to develop a consensus about the "Correct use of bone densitometry in clinical practice in Chilean population". Therefore, we elaborated 25 questions which addressed key aspects about the indications for a DXA scan, and the details of how to perform and report this test. Since some of the evidence obtained was of low quality or inconclusive, we decided to create a multidisciplinary group of national experts in osteoporosis to develop a consensus in this subject. The group consisted of 22 physicians including endocrinologists, gynecologists, geriatricians, radiologists, rheumatologists and nuclear medicine specialists. Using the Delphi methodology to analyze previously agreed questions, we elaborated statements that were evaluated by the experts who expressed their degree of agreement. The final report of this consensus was approved by the SOCHED board.

Negative spot sign in primary intracerebral hemorrhage: potential impact in reducing imaging.

Intracerebral hemorrhage (ICH) is one of the most devastating and costly diagnoses in the USA. ICH is a common diagnosis, accounting for 10-15 % of all strokes and affecting 20 out of 100,000 people. The CT angiography (CTA) spot sign, or contrast extravasation into the hematoma, is a reliable predictor of hematoma expansion, clinical deterioration, and increased mortality. Multiple studies have demonstrated a high negative predictive value (NPV) for ICH expansion in patients without spot sign. Our aim is to determine the absolute NPV of the spot sign and clinical characteristics of patients who had ICH expansion despite the absence of a spot sign. This information may be helpful in the development of a cost effective imaging protocol of patients with ICH. During a 3-year period, 204 patients with a CTA with primary intracerebral hemorrhage were evaluated for subsequent hematoma expansion during their hospitalization. Patients with intraventricular hemorrhage were excluded. Clinical characteristics and antithrombotic treatment on admission were noted. The number of follow-up NCCT was recorded. Of the resulting 123 patients, 108 had a negative spot sign and 7 of those patients subsequently had significant hematoma expansion, 6 of which were on antithrombotic therapy. The NPV of the CTA spot sign was calculated at 0.93. In patients without antithrombotic therapy, the NPV was 0.98. In summary, the negative predictive value of the CTA spot sign for expansion of ICH, in the absence of antithrombotic therapy and intraventricular hemorrhage (IVH) on admission, is very high. These results have the potential to redirect follow-up imaging protocols and reduce cost.

[Bone involvement in systemic mastocytosis: Report of two cases]. / Compromiso óseo en mastocitosis sistémica: una asociación frecuente, pero muchas veces inadvertida.

Systemic mastocytosis (SM) is characterized by pathologic expansion and activation of mast cells. The main clinical manifestations of SM include skin involvement, gastrointestinal symptoms and anaphylaxis due to the release of its mediators. Thirty percent of pat ients with SM have a low bone mass and 20% fractures. At the same time, SM affects 10% of male patients with idiopathic osteoporosis. Measuring serum tryptase is essential for the screening of MS. We report two cases of SM with bone involvement. A 25-year- old woman with prior diagnosis of SM, based on skin involvement, flushing, high serum tryptase and compatible bone marrow (BM) biopsy and genetic study. Low bone mass was diagnosed and treatment was started with calcium and vitamin D plus oral bisphosphona tes with adequate response. A 47 years old man who presented with multiple osteoporotic vertebral fractures and low bone mass. Treatment with vitamin D and alendronate was started, but the patient developed new vertebral fractures. The study was extended w ith measurement of serum tryptase that was elevated. Diagnosis of SM was confirmed with BM biopsy and the patient was referred to hematology for specific care. These cases emphasize the importance of bone assessment in SM, as well as the need to rule out S M in patients with osteoporosis and no evident cause.

Radiographers supporting radiologists in the interpretation of screening mammography: a viable strategy to meet the shortage in the number of radiologists.

BACKGROUND: An alternative approach to the traditional model of radiologists interpreting screening mammography is necessary due to the shortage of radiologists to interpret screening mammograms in many countries. METHODS: We evaluated the performance of 15 Mexican radiographers, also known as radiologic technologists, in the interpretation of screening mammography after a 6 months training period in a screening setting. Fifteen radiographers received 6 months standardized training with radiologists in the interpretation of screening mammography using the Breast Imaging Reporting and Data System (BI-RADS) system. A challenging test set of 110 cases developed by the Breast Cancer Surveillance Consortium was used to evaluate their performance. We estimated sensitivity, specificity, false positive rates, likelihood ratio of a positive test (LR+) and the area under the subject-specific Receiver Operating Characteristic (ROC) curve (AUC) for diagnostic accuracy. A mathematical model simulating the consequences in costs and performance of two hypothetical scenarios compared to the status quo in which a radiologist reads all screening mammograms was also performed. RESULTS: Radiographer's sensitivity was comparable to the sensitivity scores achieved by U.S. radiologists who took the test but their false-positive rate was higher. Median sensitivity was 73.3 % (Interquartile range, IQR: 46.7-86.7 %) and the median false positive rate was 49.5 % (IQR: 34.7-57.9 %). The median LR+ was 1.4 (IQR: 1.3-1.7 %) and the median AUC was 0.6 (IQR: 0.6-0.7). A scenario in which a radiographer reads all mammograms first, and a radiologist reads only those that were difficult for the radiographer, was more cost-effective than a scenario in which either the radiographer or radiologist reads all mammograms. CONCLUSIONS: Given the comparable sensitivity achieved by Mexican radiographers and U.S. radiologists on a test set, screening mammography interpretation by radiographers appears to be a possible adjunct to radiologists in countries with shortages of radiologists. Further studies are required to assess the effectiveness of different training programs in order to obtain acceptable screening accuracy, as well as the best approaches for the use of non-physician readers to interpret screening mammography.

Higher latitude and lower solar radiation influence on anaphylaxis in Chilean children.

BACKGROUND: Recent studies suggest an association between higher latitude, a proxy of vitamin D (VD) status, and allergic diseases. Chile provides an ideal setting to study this association due to its latitude span and high rates of VD deficiency in southern regions. The aim of this study is to explore the associations of latitude and solar radiation with anaphylaxis admission rates. METHODS: We reviewed anaphylaxis admissions in Chile's hospital discharge database between 2001 and 2010 and investigated associations with latitude and solar radiation. RESULTS: 2316 anaphylaxis admissions were registered. Median age of patients was 41 yr; 53% were female. National anaphylaxis admission rate was 1.41 per 100,000 persons per year. We observed a strong north-south increasing gradient of anaphylaxis admissions (ß 0.04, p = 0.01), with increasing rates south of latitude 34°S. A significant association was also observed between solar radiation and anaphylaxis admissions (ß -0.11, p = 0.009). Latitude was associated with food-induced (ß 0.05, p = 0.02), but not drug-induced (ß -0.002, p = 0.27), anaphylaxis. The association between latitude and food-induced anaphylaxis was significant in children (ß 0.01, p = 0.006), but not adults (ß 0.003, p = 0.16). Anaphylaxis admissions were not associated with regional sociodemographic factors like poverty, rurality, educational level, ethnicity, or physician density. CONCLUSIONS: Anaphylaxis admission rates in Chile are highest at higher latitudes and lower solar radiation, used as proxies of VD status. The associations appear driven by food-induced anaphylaxis. Our data support a possible role of VD deficiency as an etiological factor in the high anaphylaxis admission rates found in southern Chile.