Determination of Asphaltene Stability in Crude Oils Using a Deposit Level Test Coupled with a Spot Test: A Simple and Qualitative Approach.

The main goal of this study is to monitor the stability of crude oils in terms of both precipitation and deposition magnitude with respect to time. To achieve this goal, two experimental techniques which include a deposit level test and a spot test were integrated and applied simultaneously. The method was implemented using six crude oils, namely A, B, D, E, F, and G, and tests were performed at different times which split them into short duration tests and long duration tests. All crude oils were found to exhibit potential for asphaltene precipitation and subsequent deposition at different rates. Crude oils B, G, and D were observed to have started asphaltene precipitation and subsequent deposition relatively quicker. Similarly, crude oils B, A, and F exhibit a higher potential for producing asphaltene deposits in terms of deposition level. Crude oil E produces relatively fewer deposits at comparatively slower rates. The overall result indicates that crude oil B was found to be the most risky crude oil as it produces a higher quantity of deposits at higher rates, while crude oil E proved to be the least risky. Sensitivity analysis was also performed via the computing relevancy factor to determine the relative importance of two input parameters, namely the specific gravity of crude oil and the time for two-output precipitation intensity and deposition level. Precipitation intensities were found by the implementation of an image-processing tool on spot test results. The relationship between time and precipitation intensity was found to be negligible; however, the correlation between time and deposition level was found to be strongly positive with a relevancy factor value of approximately 0.521. Similarly, the relationship of the specific gravity of oil with precipitation intensity and deposition level was found to be moderately negative and very close to each other, i.e., -0.228 and -0.247, respectively. The integration of the deposit level test with the spot test allows the continuous and simultaneously reliable monitoring of both asphaltene precipitation and deposition at different times without involving cost, complex instrumentation, or interpretation, irrespective of the type of oil. The method enables the successful determination of stability ranking of different crude oils both in terms of precipitation and deposition.

Use of Platelet-Rich Plasma in Treating Low Back Pain: A Review of the Current Literature.

Low back pain (LBP) is a common problem encountered by physicians. It is a considerable cause of morbidity and socioeconomic loss and is one of the most expensive musculoskeletal disorders. Conventional treatments include bed rest, analgesics, therapeutic exercises, lumbar or caudal epidural corticosteroids, and surgery. Several new biological therapies are being investigated for use in LBP and one of these is platelet-rich plasma (PRP). In this article, we summarize the current literature published on PRP concerning its composition, classification, and application in LBP. We believe our review will prove useful to clinicians and academics alike, interested in new developing therapies for LBP.

Membranous Glomerulonephritis as an Uncommon Presentation of Secondary Syphilis: A Reminder on Therapeutic Decision-Making in Clinical Practice.

Membranous glomerulonephritis is one of the common causes of nephrotic syndrome in the adult population. It is idiopathic in the majority of patients, but the secondary forms can be seen in the setting of autoimmune disease, cancer, infection, and following exposure to certain medications. However, subclinical syphilis-related membranous nephropathy remains a particularly rare clinicopathologic entity in modern times. In this article, we chronicle an interesting case of latent syphilis masquerading as membranous glomerulonephritis, which resolved with benzathine penicillin without requiring immunosuppressive treatment. We further supplement this paper with a concise review of the relevant literature that delineates the utility of appropriate antibiotic therapy in the management of luetic membranous nephropathy. Clinicians should remain cognizant of secondary syphilis while evaluating patients for possible glomerulonephritis or those presenting with proteinuria. Additionally, patients with hepatitis B, hepatitis C, and human immunodeficiency virus infections are not infrequently coinfected with Treponema pallidum. Therefore, a high index of suspicion for systemic manifestations of syphilis such as nephrotic syndrome is warranted in the setting of a coinfection. Prompt diagnosis and treatment of syphilis may result in resolution of proteinuria, without the need for standard immunosuppressive therapy commonly used in clinical practice.

Outcomes of the 2019 novel coronavirus in patients with or without a history of cancer: a multi-centre North London experience.

BACKGROUND: This study aims to compare the outcomes of COVID-19-positive disease in patients with a history of cancer to those without. METHODS: We retrospectively collected clinical data and outcomes of COVID-19 positive cancer patients treated consecutively in five North London hospitals (cohort A). Outcomes recorded included time interval between most recent anti-cancer treatment and admission, severe outcome [a composite endpoint of intensive care unit (ITU) admission, ventilation and/or death] and mortality. Outcomes were compared with consecutively admitted COVID-19 positive patients, without a history of cancer (cohort B), treated at the primary centre during the same time period (1 March-30 April 2020). Patients were matched for age, gender and comorbidity. RESULTS: The median age in both cohorts was 74 years, with 67% male, and comprised of 30 patients with cancer, and 90 without (1:3 ratio). For cohort B, 579 patients without a history of cancer and consecutively admitted were screened from the primary London hospital, 105 were COVID-19 positive and 90 were matched and included. Excluding cancer, both cohorts had a median of two comorbidities. The odds ratio (OR) for mortality, comparing patients with cancer to those without, was 1.05 [95% confidence interval (CI) 0.4-2.5], and severe outcome (OR 0.89, 95% CI 0.4-2.0) suggesting no increased risk of death or a severe outcome in patients with cancer. Cancer patients who received systemic treatment within 28 days had an OR for mortality of 4.05 (95% CI 0.68-23.95), p = 0.12. On presentation anaemia, hypokalaemia, hypoalbuminaemia and hypoproteinaemia were identified predominantly in cohort A. Median duration of admission was 8 days for cancer patients and 7 days for non-cancer. CONCLUSION: A diagnosis of cancer does not appear to increase the risk of death or a severe outcome in COVID-19 patients with cancer compared with those without cancer. If a second spike of virus strikes, rational decision making is required to ensure optimal cancer care.

Leptomeningeal carcinomatosis as the primary presentation of relapse in breast cancer.

Leptomeningeal metastasis (LM) is an uncommon presentation of relapse in breast cancer, which is associated with poor clinical outcomes and poor prognosis. Notably, LM most commonly occurs in breast cancer. The aim of the present review was to investigate the occurrence of LM as the primary presentation of relapse following remission in breast cancer patients and to determine whether specific histological subtypes are predisposed to meningeal metastases. In addition, the present review evaluated whether patients presenting with LM as the primary site of relapse exhibit differences in survival when compared with patients exhibiting metastasis to other sites. Cross-sectional studies have demonstrated that LM is commonly associated with other sites of distant metastasis including lung, liver and bone metastases. The histological breast cancer subtype most commonly associated with LM was invasive lobular carcinoma, while triple-negative breast cancer patients appear to be predisposed to the development of LM when considering the overall prevalence of histological breast cancer subtypes. At present, data regarding LM as the primary site of relapse are limited due to its rarity as the first site of metastasis in breast cancer. Case-controlled studies are required to investigate the incidence of LM as the primary site of recurrence in breast cancer patients as this would enable treatment standardization and identification of prognostic factors for improved survival.

Histone deacetylases as new therapy targets for platinum-resistant epithelial ovarian cancer.

INTRODUCTION: In developed countries, ovarian cancer is the fourth most common cancer in women. Due to the non-specific symptomatology associated with the disease many patients with ovarian cancer are diagnosed late, which leads to significantly poorer prognosis. Apart from surgery and radiotherapy, a substantial number of ovarian cancer patients will undergo chemotherapy and platinum based agents are the mainstream first-line therapy for this disease. Despite the initial efficacy of these therapies, many women relapse; therefore, strategies for second-line therapies are required. Regulation of DNA transcription is crucial for tumour progression, metastasis and chemoresistance which offers potential for novel drug targets. METHODS: We have reviewed the existing literature on the role of histone deacetylases, nuclear enzymes regulating gene transcription. RESULTS AND CONCLUSION: Analysis of available data suggests that a signifant proportion of drug resistance stems from abberant gene expression, therefore HDAC inhibitors are amongst the most promising therapeutic targets for cancer treatment. Together with genetic testing, they may have a potential to serve as base for patient-adapted therapies.

Leptin signalling, obesity and prostate cancer: molecular and clinical perspective on the old dilemma.

The prevalence of global obesity is increasing. Obesity is associated with general cancer-related morbidity and mortality and is a known risk factor for development of specific cancers. A recent large systematic review of 24 studies based on meta-analysis of 11,149 patients with prostate cancer showed a significant correlation between obesity and the risk of advanced prostate cancer. Further, a sustained reduction in BMI correlates with a decreased risk of developing aggressive disease. On the other hand, the correlation between consuming different products and prostate cancer occurrence/risk is limited.Here, we review the role of adipose tissue from an endocrine perspective and outline the effect of adipokines on cancer metabolism, with particular focus on leptin. Leptin exerts its physiological and pathological effects through modification of intracellular signalling, most notably activating the Janus kinase (JAK) 2/signal transducer and activator of transcription (STAT) 3 pathway and recently shown sphingolipid pathway. Both high levels of leptin in circulation and leptin receptor mutation are associated with prostate cancer risk in human patients; however, the in vivo mechanistic evidence is less conclusive.Given the complexity of metabolic cancer pathways, it is possible that leptin may have varying effects on prostate cancer at different stages of its development, a point that may be addressed by further epidemiological studies.

Reproducibility of quantitative assessment of altered hepatic hemodynamics with dynamic contrast-enhanced ultrasound.

OBJECTIVES: The aim of this clinical study was to evaluate the reproducibility of quantitative assessment of altered hepatic hemodynamics with dynamic contrast-enhanced ultrasound. METHODS: Fifteen patients with colorectal liver metastases and 5 volunteers were studied. The hepatic artery proper and the portal vein were imaged simultaneously with dynamic contrast-enhanced ultrasound. The examination was repeated with 2 different contrast bolus volumes (1.2 and 2.4 mL), and time-intensity curves were formed from dynamic contrast-enhanced ultrasound image loops. The rise time, peak intensity, and wash-in slope were derived from hepatic artery and portal vein time-intensity curves. Inter-reader, intra-reader, and inter-scan agreement was assessed by 2 independent readers. Quantitative (intraclass correlation coefficients and coefficients of variation [CVs]) and qualitative (Landis and Koch classification) analyses were performed. RESULTS: Intra-reader and inter-reader agreement was "almost perfect" for the hepatic artery (CV, 10%-15% and 8%-9%, respectively), portal vein (CV, 5%-8% and 6%-12%), and hepatic artery/portal vein ratio (CV, 8%-14% and 10%-15%) measurements of 3 all studied parameters. In contrast, inter-scan agreement was only "slight" to "moderate" (CV, 25%-27%) and "fair" to "moderate" (CV, 19%-24%) for rise time and peak intensity measurements in the hepatic artery and portal vein, respectively. CONCLUSIONS: Quantitative assessment of altered hepatic hemodynamics with dynamic contrast-enhanced ultrasound is reproducible provided that measurements in the hepatic artery are normalized by those in the portal vein.

Assessment of global liver blood flow with quantitative dynamic contrast-enhanced ultrasound.

OBJECTIVES: This study assessed the potential of quantitative analysis of contrast bolus kinetics to reflect global liver blood flow. METHODS: A dynamic contrast-enhanced ultrasound flow phantom was developed. A peristaltic pump established constant volume flow ranging between 16.5 and 49.5 mL/min (2-mm tube) and 85.5 and 256.5 mL/min (5-mm tube). After bolus injection of 2 doses of a contrast agent, a region of interest was drawn over the cross section of the tube used for a particular acquisition; the rise time, peak intensity, and wash-in slope were derived from time-intensity curves. Twenty healthy volunteers and 25 patients with biopsy-proven colorectal liver metastases were scanned with dynamic contrast-enhanced ultrasound. The rise time, peak intensity, and wash-in slope were derived from hepatic artery and portal vein time-intensity curves. Hepatic artery/portal vein ratios of the parameters were also calculated. RESULTS: In the in vitro experiment, the rise time decreased while the peak intensity and wash-in slope increased with increasing volume flow for both tube diameters and contrast bolus volumes. In the clinical study, the rise time was lowered in the hepatic artery but elevated in the portal vein, and the peak intensity and wash-in slope were elevated in the hepatic artery but lowered in the portal vein in patients with colorectal liver metastases compared with healthy volunteers, although not in a statistically significant manner. This finding was consistent with an increase in hepatic artery blood flow, a decrease in portal vein blood flow, or both in patients with colorectal liver metastases compared with healthy volunteers. Only the 3 hepatic artery/portal vein ratios of the parameters achieved statistical significance in differentiating healthy volunteers from patients with colorectal liver metastases (P < .05). CONCLUSIONS: Surrogate measurements of liver blood flow may be derived from quantitative analysis of dynamic contrast-enhanced ultrasound studies. They may have potential for quick and easy assessment of altered hepatic hemodynamics.