[Epidemiological profile of patients with COVID-19 admitted to a tertiary care public hospital]. / Experiencia de la pandemia por SARS-CoV-2 en un centro hospitalario de alta complejidad en Chile.

BACKGROUND: The knowledge about the epidemiological profile of patients admitted to the hospital for severe COVID infection, allows an adequate health care planning and resource allocation. AIM: To describe the epidemiology of patients with COVID-19 admitted to a public hospital between March 2020 and July 2021. MATERIAL AND METHODS: Demographic variables, comorbidities, ventilatory support requirements, and hospital resources were recorded from clinical records and hospital databases of diagnosis related groups. The primary outcomes were overall mortality and need of ventilatory support. RESULTS: In the study period, 4,474 patients (56% males) were hospitalized with a diagnosis of COVID-19. Overall mortality was 25.8% and in-hospital mortality was 18%. Invasive and non-invasive ventilatory support was required in 1349 (30.2%) and 2060 (46%) patients, respectively. The most common comorbidities in admitted patients were diabetes mellitus (29.2%), chronic kidney disease (11.1%), and chronic liver disease (10.4%). The readmission rate was 3.2%. CONCLUSIONS: Mortality associated with COVID-19 in this hospital was similar to the rates reported abroad. Local risk predictors for this infection should be identified.

Reduced hematopoietic stem cell frequency predicts outcome in acute myeloid leukemia.

In patients with acute myeloid leukemia and low percentages of aldehyde-dehydrogenase-positive cells, non-leukemic hematopoietic stem cells can be separated from leukemic cells. By relating hematopoietic stem cell frequencies to outcome we detected poor overall- and disease-free survival of patients with low hematopoietic stem cell frequencies. Serial analysis of matched diagnostic and follow-up samples further demonstrated that hematopoietic stem cells increased after chemotherapy in patients who achieved durable remissions. However, in patients who eventually relapsed, hematopoietic stem cell numbers decreased dramatically at the time of molecular relapse demonstrating that hematopoietic stem cell levels represent an indirect marker of minimal residual disease, which heralds leukemic relapse. Upon transplantation in immune-deficient mice cases with low percentages of hematopoietic stem cells of our cohort gave rise to leukemic or no engraftment, whereas cases with normal hematopoietic stem cell levels mostly resulted in multi-lineage engraftment. Based on our experimental data, we propose that leukemic stem cells have increased niche affinity in cases with low percentages of hematopoietic stem cells. To validate this hypothesis, we developed new mathematical models describing the dynamics of healthy and leukemic cells under different regulatory scenarios. These models suggest that the mechanism leading to decreases in hematopoietic stem cell frequencies before leukemic relapse must be based on expansion of leukemic stem cells with high niche affinity and the ability to dislodge hematopoietic stem cells. Thus, our data suggest that decreasing numbers of hematopoietic stem cells indicate leukemic stem cell persistence and the emergence of leukemic relapse.

Nicotine consumption may lead to aseptic loosening in proximal mega-prosthetic femoral replacement.

BACKGROUND: Aseptic loosening after total hip arthroplasty is likely related to nicotine ingestion. However, aseptic loosening as a direct consequence of smoking habits has not been described with regard to proximal mega-prosthetic femoral replacement. The aim of the present study was to evaluate the association between nicotine consumption and aseptic loosening rates after proximal mega-prosthetic femoral replacement. MATERIALS AND METHODS: A consecutive series of patients who received mega-prosthetic replacement of the proximal femur at our hospital between 2005 and 2015 were included. Their files were reviewed and evaluated for the influence of smoking on aseptic loosening rates. All living patients were invited to complete a functional follow-up assessment at our clinic. RESULTS: Twenty-six patients with 27 prostheses were included. Five patients were active smokers, and 21 patients were non-smokers. Aseptic loosening was observed in three patients in the smoking group, whereas none of the non-smokers developed aseptic loosening. Fisher's exact test showed a relationship between nicotine consumption and aseptic loosening of the prostheses (p = 0.003). CONCLUSIONS: Smoking increases the likelihood of aseptic loosening after proximal mega-prosthetic femoral replacement. LEVEL OF EVIDENCE: Level 4 according to Oxford Centre of Evidence-Based Medicine 2011.

The rarity of ALDH(+) cells is the key to separation of normal versus leukemia stem cells by ALDH activity in AML patients.

To understand the precise disease driving mechanisms in acute myeloid leukemia (AML), comparison of patient matched hematopoietic stem cells (HSC) and leukemia stem cells (LSC) is essential. In this analysis, we have examined the value of aldehyde dehydrogenase (ALDH) activity in combination with CD34 expression for the separation of HSC from LSC in 104 patients with de novo AML. The majority of AML patients (80 out of 104) had low percentages of cells with high ALDH activity (ALDH(+) cells; <1.9%; ALDH-rare AML), whereas 24 patients had relatively numerous ALDH(+) cells (≥1.9%; ALDH-numerous AML). In patients with ALDH-rare AML, normal HSC could be separated by their CD34(+) ALDH(+) phenotype, whereas LSC were exclusively detected among CD34(+) ALDH(-) cells. For patients with ALDH-numerous AML, the CD34(+) ALDH(+) subset consisted mainly of LSC and separation from HSC was not feasible. Functional analyses further showed that ALDH(+) cells from ALDH-numerous AML were quiescent, refractory to ARA-C treatment and capable of leukemic engraftment in a xenogenic mouse transplantation model. Clinically, resistance to chemotherapy and poor long-term outcome were also characteristic for patients with ALDH-numerous AML providing an additional risk-stratification tool. The difference in spectrum and relevance of ALDH activity in the putative LSC populations demonstrates, in addition to phenotypic and genetic, also functional heterogeneity of leukemic cells and suggests divergent roles for ALDH activity in normal HSC versus LSC. By acknowledging these differences our study provides a new and useful tool for prospective identification of AML cases in which separation of HSC from LSC is possible.

Non-Destructive Measurement of the Internal Quality of Citrus Fruits Using a Portable NIR Device.

The citrus industry has grown exponentially as a result of increasing demand on its consumption, giving it high standing among other fruit crops. Therefore, the citrus sector seeks rapid, easy, and non-destructive approaches to evaluate in real time and in situ the external and internal changes in physical and nutritional quality at any stage of fruit development or storage. In particular, vitamin C is among the most important micronutrients for consumers, but its measurement relies on laborious analytical methodologies. In this study, a portable near infrared spectroscopy (NIRS) sensor was used in combination with chemometrics to develop robust and accurate models to study the ripeness of several citrus fruits (oranges, lemons, clementines, tangerines, and Tahiti limes) and their vitamin C content. Ascorbic acid, dehydroascorbic acid, and total vitamin C were determined by HILIC-HPLC-UV, while soluble solids and total acidity were evaluated by standard analytical procedures. Partial least squares regression (PLSR) was used to build regression models which revealed suitable performance regarding the prediction of quality and ripeness parameters in all tested fruits. Models for ascorbic acid, dehydroascorbic acid, total vitamin C, soluble solids, total acidity, and juiciness showed Rcv2 = 0.77-0.87, Rcv2 = 0.29-0.79, Rcv2 = 0.77-0.86, Rcv2 = 0.75-0.97, Rcv2 = 0.24-0.92, and Rcv2 = 0.38-0.75, respectively. Prediction models of oranges and Tahiti limes showed good to excellent performance regarding all tested conditions. The resulting models confirmed that NIRS technology is a time- and cost-effective approach for predicting citrus fruit quality, which can easily be used by the various stakeholders from the citrus industry.

Near Infrared Reflectance Spectroscopy Coupled to Chemometrics as a Cost-Effective, Rapid, and Non-Destructive Tool for Fish Fraud Control: Monitoring Source, Condition, and Nutritional Value of Five Common Whitefish Species.

Fish fraud is a problematic issue for the industry. For it to be properly addressed will require the use of accurate, rapid, and cost-effective tools. In this work, near infrared reflectance spectroscopy (NIRS) was used to predict nutritional values (protein, lipids, and moisture) as well as to discriminate between sources (farmed vs. wild fish) and conditions (fresh or defrosted fish). Samples of five whitefish species-Alaskan pollock (Gadus chalcogrammu), Atlantic cod (G. morhua), European plaice (Pleuronectes platessa), common sole (Solea solea), and turbot (Psetta maxima)-including farmed, wild, fresh, and frozen ones, were scanned by a low-cost handheld near infrared reflectance spectrometer with a spectral range between 900 and 1700 nm. Several machine learning algorithms were explored for both regression and classification tasks, achieving precisions and coefficients of determination higher than 88% and 0.78, respectively. Principal component analysis (PCA) was used to cluster samples according to classes where good linear discriminations were denoted. Loadings from PCA revealed bands at 1150, 1200, and 1400 nm as the most discriminative spectral regions regarding classification of both source and condition, suggesting the absorbance of OH, CH, CH2, and CH3 groups as the most important ones. This study shows the use of NIRS and both linear and non-linear learners as a suitable strategy to address fish fraud and fish QC.

Experiencia de la pandemia por SARS-CoV-2 en un centro hospitalario de alta complejidad en Chile

Background: The knowledge about the epidemiological profile of patients admitted to the hospital for severe COVID infection, allows an adequate health care planning and resource allocation. Aim: To describe the epidemiology of patients with COVID-19 admitted to a public hospital between March 2020 and July 2021. Material and Methods: Demographic variables, comorbidities, ventilatory support requirements, and hospital resources were recorded from clinical records and hospital databases of diagnosis related groups. The primary outcomes were overall mortality and need of ventilatory support. Results: In the study period, 4,474 patients (56% males) were hospitalized with a diagnosis of COVID-19. Overall mortality was 25.8% and in-hospital mortality was 18%. Invasive and non-invasive ventilatory support was required in 1349 (30.2%) and 2060 (46%) patients, respectively. The most common comorbidities in admitted patients were diabetes mellitus (29.2%), chronic kidney disease (11.1%), and chronic liver disease (10.4%). The readmission rate was 3.2%. Conclusions: Mortality associated with COVID-19 in this hospital was similar to the rates reported abroad. Local risk predictors for this infection should be identified.

Acute leg pain with suspected beginning leg compartment syndrome and deep vein thrombosis as differential diagnoses in an unusual presentation of Brodie's abscess: a case report.

BACKGROUND: Brodie's abscess is an uncommon form of subacute osteomyelitis where the main presenting symptom is mild to moderate pain of insidious onset for several months' duration. We report a case of a patient presenting with acute leg pain resembling that of a deep vein thrombosis, and a beginning leg compartment syndrome following a suspected ruptured Baker's cyst. Our case is unusual because of the acute presentation of the Brodie's abscess with acute leg pain and acute swelling without any preceding trauma; to the best of our knowledge, this presentation has not been reported before. CASE PRESENTATION: A 17-year-old white boy presented to our out-patient clinic with a 6-month history of pain in his left knee joint of insidious onset. There was no history of trauma to the extremity. After performing physical and radiological (X-ray) examinations, we initially diagnosed medial meniscus damage. One week later he presented to our emergency department with acute sudden increase in the pain and swelling of his left knee, and pain and swelling of his left leg, without any trauma. Deep vein thrombosis and beginning leg compartment syndrome from ruptured Baker's cyst were initially diagnosed. Magnetic resonance imaging was performed and Brodie's abscess was the most probable diagnosis. We performed open surgical debridement and curettage with drainage of the abscess and administered postoperative antibiotics. He presented to our out-patient clinic 3 months postoperatively, where he was pain-free with no residual local tenderness. CONCLUSIONS: In cases of sudden acute increase in joint or extremity pain or swelling that has been insidiously present for months, Brodie's abscess should be considered as one of the differential diagnoses, as it may present acutely in cases with accompanying fasciitis and myositis and be clinically mistaken for deep vein thrombosis or limb compartment. Magnetic resonance imaging remains the gold standard imaging study, and surgical treatment followed by postoperative antibiotics remains the standard treatment.

Set screw fracture with cage dislocation after two-level transforaminal lumbar interbody fusion (TLIF): a case report.

INTRODUCTION: Transforaminal lumbar interbody fusion is a popular procedure used to achieve spondylodesis in patients with degenerative lumbar spinal diseases. We present a rare case of a patient with a set screw fracture with cage dislocation after an open transforaminal lumbar interbody fusion procedure. To the best of our knowledge, this case is the first of its kind to be reported. CASE PRESENTATION: A 44-year-old Caucasian woman attended a follow-up appointment at our hospital 3 months after treatment for second-degree lumbar spondylolisthesis (L4/L5) and osteochondrosis (L5/S1) with transforaminal lumbar interbody fusion and dorsal spondylodesis. She complained of severe leg pain on the left side. Her physical examination revealed a normal neurological status, except for paresthesia of the entire left lower limb and at the ball of the left foot. Radiological imaging showed breaking of the set screws with cage dislocation. Surgical revision was then performed with exchange of the whole dorsal instrumentation and the dislocated cage. Six weeks post-operatively, the patient was seen again at our clinic without neurological complaints, except for decreased sensitivity on the dorsum of her left foot. The wound healing and radiological follow-up were uneventful. CONCLUSIONS: Hardware-related complications are rarely seen in patients with open transforaminal lumbar interbody fusion, but must be kept in mind and can potentially cause severe neurological deficits.

Differences between healthy hematopoietic progenitors and leukemia cells with respect to CD44 mediated rolling versus adherence behavior on hyaluronic acid coated surfaces.

We previously demonstrated that leukemia cell lines expressing CD44 and hematopoietic progenitor cells (HPC) from umbilical cord blood (CB) showed rolling on hyaluronic acid (HA)-coated surfaces under physiological shear stress. In the present study, we quantitatively assessed the interaction of HPC derived from CB, mobilized peripheral blood (mPB) and bone marrow (BM) from healthy donors, as well as primary leukemia blasts from PB and BM of patients with acute myeloid leukemia (AML) with HA. We have demonstrated that HPC derived from healthy donors showed relative homogeneous rolling and adhesion to HA. In contrast, highly diverse behavioral patterns were found for leukemia blasts under identical conditions. The monoclonal CD44 antibody (clone BU52) abrogated the shear stress-induced rolling of HPC and leukemia blasts, confirming the significance of CD44 in this context. On the other hand, the immobile adhesion of leukemia blasts to the HA-coated surface was, in some cases, not or incompletely inhibited by BU52. The latter property was associated with non-responsiveness to induction chemotherapy and subsequently poor clinical outcome.

Identification and separation of normal hematopoietic stem cells and leukemia stem cells from patients with acute myeloid leukemia.

Mounting evidences indicate that leukemic cells in patients with acute myeloid leukemia (AML) are derived from leukemia stem cells (LSC). In analogy to normal hematopoietic stem cells (HSC), LSC remain mostly dormant and are hence resistant to conventional chemotherapy. Residual, physiological HSC exist alongside with LSC, with heterogeneous dominance of LSC over HSC in individual patients. We have devised a flow cytometric method for the identification and separation of these two stem cell populations based on surface antigen markers such as CD34, CD38, lineage aberrant markers, and aldehyde dehydrogenase (ALDH) enzyme activity.