Theoretical and Computational Analysis of the Thermal Quasi-Geostrophic Model.

This work involves theoretical and numerical analysis of the thermal quasi-geostrophic (TQG) model of submesoscale geophysical fluid dynamics (GFD). Physically, the TQG model involves thermal geostrophic balance, in which the Rossby number, the Froude number and the stratification parameter are all of the same asymptotic order. The main analytical contribution of this paper is to construct local-in-time unique strong solutions for the TQG model. For this, we show that solutions of its regularised version α-TQG converge to solutions of TQG as its smoothing parameter α→0 and we obtain blow-up criteria for the α-TQG model. The main contribution of the computational analysis is to verify the rate of convergence of α-TQG solutions to TQG solutions as α→0, for example, simulations in appropriate GFD regimes.

Pinning potential in highly performant CaKFe4As4 superconductor from DC magnetic relaxation and AC multi-frequency susceptibility studies.

We have investigated the pinning potential of high-quality single crystals of superconducting material CaKFe4As4 having high critical current density and very high upper critical field using both magnetization relaxation measurements and frequency-dependent AC susceptibility. Preliminary studies of the superconducting transition and of the isothermal magnetization loops confirmed the high quality of the samples, while temperature dependence of the AC susceptibility in high magnetic fields show absolutely no dependence on the cooling conditions, hence, no magnetic history. From magnetization relaxation measurements were extracted the values of the normalized pinning potential U*, which reveals a clear crossover between elastic creep and plastic creep. The extremely high values of U*, up to 1200 K around the temperature of 20 K lead to a nearly zero value of the probability of thermally-activated flux jumps at temperatures of interest for high-field applications. The values of the creep exponents in the two creep regimes resulted from the analysis of the magnetization relaxation data are in complete agreement with theoretical models. Pinning potentials were also estimated, near the critical temperature, from AC susceptibility measurements, their values being close to those resulted (at the same temperature and DC field) from the magnetization relaxation data.

The preoperative evaluation of post-COVID-19 patients scheduled for elective surgery - What is important not to miss!

Continuous rise in the number of COVID-19 cases, since it was first diagnosed in 2019, forced the entire medical fraternity to delay elective surgeries. The preoperative evaluation guidelines that were used in the pre-COVID-19 era underwent significant changes, adding modifications to meet the post-COVID patients' specific criteria and requirements. Currently, all patients before or at the time of hospital admission were tested using a nasopharyngeal swab, by RT-PCR for SARS-CoV-2. Apart from this, for a patient undergoing elective surgery in their post-COVID-19 period, it is mandatory to obtain a detailed history of COVID-19 disease/SARS-CoV-2 infection, to identify residual symptoms or any organ dysfunction the infection might have caused. As well as the functional optimization of the patient to achieve the best clinical and biological status before the surgery. After all the systems have been thoroughly investigated, the risk-benefit ratio needs to be calculated, keeping in mind the cytokine storm and inflammatory responses encountered postoperatively. A mere negative RT-PCR test cannot be considered as the only decisive factor to operate, as the post-COVID-19 phase can influence postoperative outcome of the patient. Hence, the pre-operative evaluation protocols of post-COVID patients should be set and followed thoroughly, in order to avoid post-surgical complications. For better surgical and post-surgical management of post-COVID-19 patients, conducting clinical tests, assessing previously administered medications, evaluating the need for deep venous thrombosis prophylaxes, and identifying subclinical inflammatory state are the measures that should be taken.

Selecting the right anticoagulant for stroke prevention in atrial fibrillation.

OBJECTIVE: The embolization of thrombi formed within the atria can occur in any form of atrial fibrillation (AF), i.e., paroxysmal, persistent, or permanent. Although ischemic stroke is the most frequent embolic event associated with AF, embolization to other sites in the pulmonary and systemic circulations may occasionally occur. To avert the risk of embolization, long-term oral anticoagulation therapy is recommended for all AF patients if the CHA2DS2-VASC score is at least 1 for men and at least 2 for women. Since anticoagulant therapy is associated with an increased risk of bleeding, the choice of oral anticoagulant agent should be made by careful consideration of the benefit-to-risk ratio. The use of a newer class of direct oral anticoagulants (DOACs) as an alternative to the anti-vitamin K (AVK) anticoagulants (warfarin, acenocumarol, etc.) can help mitigate the need for periodic monitoring of International Normalized Ratio (INR) and adverse bleeding events that are commonly associated with the use of AVK anticoagulants. Though the use of DOACs (dabigatran, rivaroxaban, edoxaban, apixaban, etc.) is gaining ground due to their relative safety profile and the low overall cost, quite a few clinicians remain skeptical about their use. PATIENTS AND METHODS: Our objective was to evaluate the risk of thromboembolism, stroke, neuropsychiatric illness, depression, and dementia, in patients with non-valvular atrial fibrillation who have been treated with either acenocumarol or apixaban, as well as to see the inflammatory status (ESR) and levels of fibrinogen. Our team at Municipal Emergency University Hospital, Timisoara, Romania, conducted a retrospective study using the medical records of AF patients who were treated with either apixaban or acenocumarol between 2016-2019. We divided the patients into two groups and compared the groups for the aforementioned outcomes. RESULTS: AF patients who were prescribed apixaban had a lower rate of stroke and psychiatric illness compared to those on acenocumarol. No significant correlation was found in terms of risk of developing depression or dementia between the groups. CONCLUSIONS: Non-valvular AF patients on apixaban had lower rates of thromboembolic events than the patients on acenocumarol. This article will serve as a reminder of the positive health and financial outcomes of apixaban use, especially to those healthcare systems that are still oblivious to the decrease in economic burden and gain in quality-adjusted life years (QALY) by the long-term use of NOACS/ DOACS instead of the AVK anticoagulants.

Association between PNPLA3[G]/I148M variant, steatosis and fibrosis stage in hepatitis C virus - genetic matters.

There is an established correlation between the PNPLA3 rs738409 C > G single nucleotide polymorphism (SNP) and hepatic steatosis and fibrosis in hepatitis C virus (HCV) infected patients. However not all data is convergent regarding the exact impact of this SNP on the pattern of disease progression in different clinical settings. In this study, we aimed to further bridge the knowledge gap on this topic by investigating the role of the G allele in promoting steatosis, fibrosis and disease progression in relation to other metabolic and anthropometric host factors. Two hundred and fifty consecutive patients, previously diagnosed with chronic hepatitis C (CHC) underwent liver biopsy. Histology was assessed using the Metavir scoring system. Transient elastography was used for follow-up. Ninety-eight patients were genotyped for PNPLA3 rs738409 and followed up for fibrosis progression. PNPLA3 rs738409[G] allele was significantly correlated with severe steatosis (P = 0.04), severe fibrosis at the time of enrollment (P = 0.0005) and fibrosis progression with an OR of 10.31 (95% CI 1.06 - 99.59, P = 0.04), after a mean follow-up time of 62.85 (95%CI: 52.21 - 76.15) months. Severe steatosis at the time of enrollment had an OR of 11.02 (95% CI 1.48 - 82.09, P = 0.01) for the association with fibrosis progression. The HOMA-IR index was also positively correlated with severe fibrosis (P = 0.03) and fibrosis progression on univariate analysis (P = 0.02). PNPLA3 rs738409[G] allele is a reliable predictor for steatosis and fibrosis in CHC. The presence of G allele, along with severe steatosis and insulin resistance are significant predictors for fibrosis progression.

Thrombophlebitis of the lateral chest wall (Mondor's disease).

Mondor's disease is a rare condition, which involves the thrombophlebitis of the superficial veins of the breast and anterior chest wall. A 37-year-old woman presented with sudden onset of local pain and edema on her right chest wall, accompanied by a longitudinal retraction of the skin during arm abduction in the area. Clinical, histological and ultrasonographic findings confirmed Mondor's disease and the treatment was symptomatic, using pain relievers and warm compresses. The symptomatology remitted within 2 weeks of therapy. Mondor's disease is a rare condition where ultrasound complements the clinical evaluation and allows the characterization of certain abnormalities, which correlated with functional biochemical data and other procedures may substitute the need of biopsy.

A novel pathophysiological-based panel of biomarkers for the diagnosis of nonalcoholic steatohepatitis.

Non-invasive biochemical markers are useful to distinguish between nonalcoholic steatohepatitis (NASH) and simple steatosis. The aim of this study was to test the diagnostic value of a panel of biomarkers derived from the pathophysiological events involved in the development of NASH. A total of 79 patients: 20 not-NASH and 59 NASH were included in the study. Definitive NASH was defined according to Kleiner's classification. In all subjects, parameters of the metabolic syndrome, insulin resistance (HOMA-IR), adiponectin, interleukin-6 (IL-6) and total cytokeratin-18 (M65 antigen) were determined. Univariate and multivariate analysis were used to identify independent predictors of NASH. In multivariate analysis three markers were independently predictors of NASH: adiponectin, IL-6 and M65 levels. In decreasing order, the independent predictors of NASH (NAS≥5) were M65 with an AUROC of 0.791, IL-6 with an AUROC of 0.727 and adiponectin with an AUROC of 0.709. The combination of two biomarkers yelded an AUROC of 0.828 for M65 and IL-6, 0.841 for adiponectin and M65 and 0.852 for adiponectin and IL-6. The best value was obtained by triple combination: adiponectin, M65 and IL-6 with and AUROC of 0.903, Sp=85.7% (PPV=94.2%) and Se=84.5% (NPV=66.7%). In conclusion, a novel pathophysiological - based panel of biomarkers combining total CK-18, IL-6 and adiponectin may be useful to predict NASH.

Acute diverticulitis--an unusual cause of liver abcesses in a young man: a case report.

Liver abscess is a rare complication of sigmoid diverticulitis and must be considered within the differential diagnosis. We report a case of a male patient, age 42, admitted to our hospital with chief complaints of a dull pain in upper right abdominal quadrant, fever, weakness, diarrhoea and weight loss of approximately 3 weeks duration. Physical examination on initial work-up revealed tenderness on palpation in upper right abdomen, and left iliac fosa and a 39 degrees C fever. Biochemistry showed marked inflammatory syndrome, leukocitosis, increased level of platelets, altered liver function. Ultrasound examination revealed inhomogeneous liver nodules and the thickening of the sigmoid wall. Further CT scan examination and MRI confirmed the lesions as beeing abscesses and also revealed trombosis of right portal vein. The sigmoid wall lesions proved to be an acute diverticulitis with perisigmoiditis, stenosis and abscess. Patient underwent a surgical treatment of sigmoid resection, but the punction of the abscesses revealed no pus at aspiration, making the surgical excision of the lesions unnecessary. After the surgery, during the antibiotic treatment, the patient developed pseudomembranous colitis treated with specific antibiotics. The evolution under this treatment was positive and the aspect of the liver lesions was improuved.

Compression and walking compared with bed rest in the treatment of proximal deep venous thrombosis during pregnancy.

UNLABELLED: The purpose was to evaluate the benefits of compression and early mobilization in comparison with compression and bed rest in the acute stage of proximal deep venous thrombosis (DVT) in pregnant women. METHOD: Thirty-two consecutive pregnant women with proximal DVT diagnosed by color duplex ultrasound were divided into two groups. Group A consisted of 15 patients who received elastic compression bandages and early mobilization, and group B including 17 patients with compression bandages and bed rest. All patients received heparin therapy. The clinical characteristics of the two groups were comparable. We assessed the reduction of subjective pain daily with a Visual Analogue Scale (VAS) and the objective pain using Lowenberg test, the reduction of edema was recorded initially and on day 2, 4 and 7. Ultrasound was repeated after seven days. RESULTS: Resolution of subjective pain was faster during the first three days and near absent at the end of the study period in group A (p < 0.001). Objective pain seriously reduced in group A during the observation period while in group B decreased during the first three days almost by half but remained constantly present over the remaining days (p < 0.001). The same was true for the measurement of leg circumference (p < 0.05). There was no pulmonary embolism and progression of thrombus diameter. CONCLUSION: Pregnant women with proximal deep vein thrombosis may benefit from leg compression and early mobilization for a faster resolution of the signs and symptoms and this method does not seem to be an additional risk factor for pulmonary embolism.

[Fractal analysis in the diagnosis of breast tumors]. / Utilizarea spectrului fractal în diagnosticarea leziunilor mamare.

Last years studies made by researchers from over the world show that fractal geometry is a viable alternative for image analysis. Fractal features of natural forms give to fractal analysis new valences in various fields, medical imaging being a very important one. This paper intend to prove that fractal dimension, as a way to characterize the complexity of a form, can be used for diagnosis of mammographic lesions classified BI-RADS 4, further investigations being not necessary. The experiments made on 30 cases classified BI-RADS 4 confirmed that 89% of benign lesions have an average fractal dimension under the threshold 1.4, meanwhile malign lesions are characterized, in a similar percentage, by an average fractal dimension over that threshold.

Hepatosplenic gamma/delta T-cell lymphoma in immunocompromised patients. Report of two cases and review of literature.

We describe 2 male patients in whom hepatosplenic gamma/delta T-cell lymphoma (HSTL) developed 6 and 10 years after renal transplantation. The onset was abrupt with systemic symptoms, cytopenia, and hepatosplenomegaly. The histologic examination of the spleen (case 1), liver, and bone marrow revealed sinusoidal infiltrates of markedly abnormal lymphocytes. The neoplastic cells in these cases were CD2+, CD3+, CD4-, CD5-, CD7+, CD8+, CD16+, CD56+, beta F1-negative, and TIA-1-negative. Both cases displayed clonal rearrangement of the T-cell receptor (TCR) delta gene and the TCR beta gene. The spleen in case 1 was positive for Epstein-Barr virus genome and showed TCR-gamma gene rearrangement by polymerase chain reaction. Isochromosome 7 [i(7)(q10)] was found in each case. Both patients died within 4 months of diagnosis. HSTL has been reported in only 5 renal transplant recipients. HSTL may be relatively more frequent in immunocompromised patients compared with the general population.

Combined factor V Leiden and prothrombin genotyping in patients presenting with thromboembolic episodes.

BACKGROUND: Several genetic defects are associated with increased risk of venous thrombosis. The factor V Leiden (FVL) and prothrombin G20210A mutations are the most frequent causes of inherited thrombophilia. OBJECTIVES: To evaluate combined genotyping for these 2 mutations in patients presenting with thromboembolic episodes and to correlate genotypic findings with clinical characteristics. RESULTS: Blood specimens were collected from 401 patients presenting with thromboembolic disease between January 1998 and September 1998, and genotyping for both FVL and prothrombin mutations was performed. Thirty-two patients (8%) were heterozygous for FVL, 4 (1%) were homozygous for FVL, and 20 (5%) were heterozygous for the prothrombin mutation. Two cases (0.5%) were identified with combined FVL and prothrombin mutations. The most common clinical presentation was lower-extremity deep vein thrombosis with or without pulmonary embolism. Arterial events were rare. The thromboembolic episodes were often precipitated by additional risk factors. Recurrent disease was found in 73.9% of FVL carriers and 52.9% of prothrombin mutation carriers; 52% of the patients with FVL and 50% of prothrombin mutation carriers had a first thrombotic episode before age 45 years. The 2 cases with combined genetic defects demonstrate amplified thrombotic risk. In the first case this was effected in thrombosis at a young age, and recurrence of thrombotic events even in the absence of precipitating factors. A complex interplay between genetic and additional risk factors was seen in the second case. CONCLUSIONS: Identification of both FVL and prothrombin mutations is important in the overall assessment and management of patients with thrombophilia. Detection of these mutations can identify patients at high risk and help evaluate the interaction of genetic and acquired risk factors.

Detection of circulating epithelial cells after surgery for benign breast disease.

BACKGROUND: Cytokeratins are predominantly expressed in epithelial cells and their malignant counterparts. Ultrasensitive methods for cytokeratin messenger RNAs (mRNAs) can detect rare circulating tumor cells consistent with hematogenous dissemination in epithelial-derived malignancies, including breast carcinomas. Intraoperative tumor-cell shedding may contribute to this process; this hypothesis is based on the assumption that only tumor cells can be mobilized during surgical manipulation. METHODS AND RESULTS: The present study addresses this issue by using cytokeratin 19 mRNA detection by reverse transcription-polymerase chain reaction (RT-PCR) in preoperative and postoperative blood samples from 54 patients undergoing excisional biopsy for benign breast disease; 22 healthy volunteers represented the control group. No cytokeratin RT-PCR positivity was found in the control or preoperative samples. Cytokeratin RT-PCR positivity was found in 21 postoperative samples (39%). CONCLUSIONS: This finding shows that benign epithelial cells can be mobilized during breast surgery; this effect of surgical manipulation warrants caution in the interpretation of RT-PCR positivity for cytokeratin mRNA in the peripheral blood of patients undergoing surgery for breast cancer.

Molecular mechanisms in myelodysplastic syndromes and implications for evolution to acute leukemias.

This article reviews the molecular lesions that occur in the clonal hematopoietic disorders classified as myelodysplastic syndromes (MDS). A systematization of these molecular lesions is attempted based on the types of molecular abnormalities. Characteristically, these molecular lesions affect pluripotent hematopoietic progenitors and therefore affect myeloid, monocytic, erythroid, and megakaryocytic lineages. Progression of MDS to acute myelogenous leukemia is common; transformation is considered the final stage in the multi-step process of accumulation of molecular lesions over a prolonged latency period of MDS evolution. Although no molecular lesion is MDS specific, multiple combinations of molecular lesions are common and a systematic approach based on the type of molecular abnormality may offer a better understanding of MDS pathogenesis and the basis for new therapeutic strategies.