Quantifying pulse oximeter accuracy during hypoxemia and severe anemia using an in vitro circulation system.

Anemia and hypoxemia are common clinical conditions that are difficult to study and may impact pulse oximeter performance. Utilizing an in vitro circulation system, we studied performance of three pulse oximeters during hypoxemia and severe anemia. Three oximeters including one benchtop, one handheld, and one fingertip device were selected to reflect a range of cost and device types. Human blood was diluted to generate four hematocrit levels (40%, 30%, 20%, and 10%). Oxygen and nitrogen were bubbled through the blood to generate a range of oxygen saturations (O2Hb) and the blood was cycled through the in vitro circulation system. Pulse oximeter saturations (SpO2) were paired with simultaneously-measured O2Hb readings from a reference CO-oximeter. Data for each hematocrit level and each device were least-squares fit to a 2nd-order equation with quality of each curve fit evaluated using standard error of the estimate. Bias and average root mean square error were calculated after correcting for the calibration difference between human and in vitro circulation system calibration. The benchtop oximeter maintained good accuracy at all but the most extreme level of anemia. The handheld device was not as accurate as the benchtop, and inaccuracies increased at lower hematocrit levels. The fingertip device was the least accurate of the three oximeters. Pulse oximeter performance is impacted by severe anemia in vitro. The use of in vitro calibration systems may play an important role in augmenting in vivo performance studies evaluating pulse oximeter performance in challenging conditions.

Surgical Management of Breast Cancer in Africa: A Continent-Wide Review of Intervention Practices, Barriers to Care, and Adjuvant Therapy.

Breast cancer has emerged as a leading cancer among women in Africa, necessitating improved understanding of its management across the continent. Although previous studies have described regional trends in therapy, this review aims to summarize continent-wide management and focus specifically on surgical interventions. Current literature shows that the rates of surgery, chemotherapy, and radiation therapy vary across different countries and institutions, indicating the need for greater use of standardized cancer treatment guidelines. Surgery, primarily modified radical mastectomy, is the most common form of therapy described. When chemotherapy is offered, the limited availability and cost of treatment lead to high rates of interruption and premature termination of cycles. Few patients have access to radiation or hormonal therapy because these treatments are not available in many countries. Significant delays in seeking treatment are common and contribute to patients presenting with advanced disease. Although limited infrastructure favors surgical management, interventions to improve early detection behavior, provide timely referrals to medical care, and initiate early treatment with access to clinically justified neo-adjuvant and adjuvant therapy are key to improving prognosis.

Immunomodulatory Properties of Filamentous Fungi Cultivated through Solid-State Fermentation on Rapeseed Meal.

Water extracts from solid-state fermentation (SSF) on rapeseed meal using filamentous fungi exhibit interesting immunomodulatory activities in vitro. Immunomodulation was determined by the capacity of the compounds to activate blood neutrophils and to influence cytokine production in human peripheral blood mononuclear cells (PBMC) and mouse bone marrow-derived macrophages (BMDM). Among the strains tested, Aspergillus sojae mycelium and SSF extracts were the most promising in terms of enhancing the immune response. The filamentous fungus was also successfully cultivated in a pre-pilot bioreactor with forced aeration. The results indicated that the extracts not only activated blood neutrophils but also significantly modulated IL-1ß cytokine levels with lipopolysaccharide (LPS)-stimulated PBMC and BMDM without any cytotoxicity in immune cells. IL-1ß was down-regulated in a dose-dependent manner in the presence of A. sojae crude mycelium and SSF extract with PBMC, which indicated that there was an anti-inflammatory activity, whereas IL-1ß secretion was up-regulated in the presence of stimulated BMDM with the highest concentration that was tested (100 µg/mL). The non-fermented rapeseed had no effect at the same concentration. SSF culture, as a natural product, may be a good source for the development of functional feed with an immunostimulating effect or could potentially be used in medicinal applications.

The Skeletal Effects of Inhaled Glucocorticoids.

The skeletal effects of inhaled glucocorticoids are poorly understood. Children with asthma treated with inhaled glucocorticoids have lower growth velocity, bone density, and adult height. Studies of adults with asthma have reported variable effects on BMD, although prospective studies have demonstrated bone loss after initiation of inhaled glucocorticoids in premenopausal women. There is a dose-response relationship between inhaled glucocorticoids and fracture risk in asthmatics; the risk of vertebral and non-vertebral fractures is greater in subjects treated with the highest doses in the majority of studies. Patients with COPD have lower BMD and higher fracture rates compared to controls, however, the majority of studies have not found an additional detrimental effect of inhaled glucocorticoids on bone. While the evidence is not conclusive, it supports using the lowest possible dose of inhaled glucocorticoids to treat patients with asthma and COPD and highlights the need for further research on this topic.

Abnormalities in cortical bone, trabecular plates, and stiffness in postmenopausal women treated with glucocorticoids.

CONTEXT: The mechanisms by which glucocorticoids (GCs) increase skeletal fragility are not well understood. OBJECTIVE: The objective of the study was to evaluate the microarchitecture, trabecular morphology, and biomechanical properties of bone in postmenopausal women treated with GCs. DESIGN: This was a case-control study. SETTING: The study was conducted at a university hospital outpatient facility. PATIENTS: Postmenopausal women treated with oral GCs for longer than 3 months (n = 30) and age/race-matched controls (n = 60) participated in the study. MAIN OUTCOME MEASURES: Areal bone mineral density aBMD (BMD) by dual-energy x-ray absorptiometry (DXA) was measured. Trabecular and cortical volumetric BMD (vBMD) and microarchitecture by high-resolution peripheral computed tomography of the distal radius and tibia were also measured. Whole-bone stiffness was estimated by finite element analysis. A novel technique, individual trabecula segmentation, was used to evaluate trabecular type (as plate or rod), orientation, and connectivity. RESULTS: DXA T-scores did not differ significantly at any site. GC subjects had significantly lower total, cortical, and trabecular vBMD and thinner cortices, fewer, thinner, more widely, and irregularly spaced trabeculae. They had fewer trabecular plates, fewer axially aligned trabeculae, and lower trabecular connectivity. Differences ranged from 4% to 65% for these trabecular measures and 5% to 17% for the cortical measures. Whole-bone stiffness was significantly lower (11%-16%) in GC subjects. Markers of bone formation (osteocalcin and amino-terminal propeptide of type I procollagen) and resorption (C-telopeptide) were lower in the GC subjects. CONCLUSIONS: Despite similar areal BMD by DXA, GC-treated women had abnormal cortical and trabecular vBMD and microarchitecture at both the radius and tibia, including fewer trabecular plates, a less axially aligned trabecular network, lower trabecular connectivity, thinner cortices, and lower whole-bone stiffness. Further research into these abnormalities as mechanisms for fracture in GC-treated women is warranted.