Single-run reversed-phase HPLC method for determining sertraline content,enantiomeric purity,and related substances in drug substance and finished product

A direct enantio-, diastereo-, and chemo-selective high-performance liquid chromatographic method was developed for determining the content, enantiomeric purity, and related substances of the chiral antidepressant drug sertraline HCl in a single chromatographic run. The separation was achieved on a chiral stationary phase based on amylose tris(3-chloro-5-methylphenylcarbamate) under reversed-phase conditions. The method was optimized by evaluating the influence of the temperature and mobile phase composition on the retention and selectivity. The application of the single-run approach allowed to baseline resolve all investigated species in less than 15 min, without using buffers or tandem-coupled columns. The chromatographic method was validated according to the guidelines of the Official Medicines Control Laboratory and applied to control the content of sertraline HCl and related chiral substances in a generic antidepressant formulation.     

Increased Circulating Levels of Vitamin D Binding Protein in MS Patients

Vitamin D (vitD) low status is currently considered a main environmental factor in multiple sclerosis (MS) etiology and pathogenesis. VitD and its metabolites are highly hydrophobic and circulate mostly bound to the vitamin D binding protein (DBP) and with lower affinity to albumin, while less than 1% are in a free form. The aim of this study was to investigate whether the circulating levels of either of the two vitD plasma carriers and/or their relationship are altered in MS. We measured DBP and albumin plasma levels in 28 MS patients and 24 healthy controls. MS patients were found to have higher DBP levels than healthy subjects. Concomitant interferon beta therapy did not influence DBP concentration, and the difference with the control group was significant in both females and males. No significant correlation between DBP and albumin levels was observed either in healthy controls or in patients. These observations suggest the involvement of DBP in the patho-physiology of MS.     

Understanding the pathogenesis of type 2 diabetes: can we get off the metabolic merry-go-rounds?

The aetiology of non-insulin-dependent diabetes mellitus (NIDDM) is not known. The concordance of NIDDM in identical twins and differences in the prevalence rate of NIDDM between different racial groups suggest a genetic cause. Hyperglycaemia in established diabetes is caused by a combination of hepatic insulin resistance, impaired peripheral (muscle and fat) glucose uptake and a defect in glucose-mediated insulin secretion. However, it is not known if these defects are all inherited or if one can cause the others. This uncertainty is due to the fact that hyperglycaemia per se can cause defects in insulin action and insulin secretion that resemble those found in NIDDM. Furthermore the elevated free fatty acid (FFA) levels found when NIDDM is associated with obesity are known to cause both peripheral and hepatic insulin resistance. Recently we have demonstrated the mechanism by which elevated FFA levels can cause hepatic insulin resistance. However, we also have evidence that the converse holds in that genetically engineered hepatic insulin resistance in a transgenic rat model leads to obesity. Thus an understanding of the pathogenesis of NIDDM is complicated by the fact that hyperglycaemia and obesity can be both causes and consequences of insulin resistance. To overcome these difficulties, studies in young, euglycaemic diabetes-prone subjects have been conducted. Results suggest that there may be different causes for NIDDM in different racial groups.     

Serum free medium increases expression of markers of differentiation in human colonic crypt cells.

In colitis, colonic epithelial cells have a shortened life span but show normal or increased expression of phenotypic markers of differentiation. This study examined the effect of differing culture conditions on the expression of such markers in colonic crypt cells. Crypt cells were enzymatically isolated from macroscopically normal large bowel mucosa resected because of neoplasia, inflammatory bowel disease or non-neoplastic non-inflammatory conditions. Cells cultured in the presence of serum exhibited a doubling of the rate of protein synthesis (measured by 14C-leucine uptake; p < 0.001) compared with autologous cells cultured in the absence of serum without evidence of loss of cell viability (assessed by 51Cr release from prelabelled cells) or of change in the rate of cell proliferation (assessed by total DNA content and 3H-thymidine uptake). Irrespective of the underlying colonic disease, crypt cells cultured in the absence of serum exhibited increased expression of phenotypic markers of differentiation compared with those cultured with serum: the rate of glycoprotein synthesis relative to that of protein synthesis increased by a mean of 59% and the cellular expression of brush border glycoproteins, alkaline phosphatase, and carcinoembryonic antigen significantly increased. The effects seen could not be mimicked by addition of dexamethasone or insulin to serum free medium. Thus, under less optimal (serum free) culture conditions, colonic crypt cells express phenotypic markers of differentiation at an accelerated rate suggesting that unfavourable microenvironmental conditions themselves are probably in part responsible for the normal or increased expression of such markers in colitis.     

High risk of early resistant relapse for leukaemic patients with presence of multidrug resistance associated P-glycoprotein positive cells in complete remission

The immunocytochemical detection of multidrug-resistance (MDR) associated P-glycoprotein (P-170) was longitudinally performed on bone marrow smears from 32 responsive patients with acute leukaemia in the different phases of the disease (at diagnosis, in complete remission, at relapse) by means of APAAP technique and monoclonal antibody C219. The whole group of eight patients with presence of P-170 positive cells while in complete remission rapidly relapsed with a high proportion of blasts showing MDR phenotype; they were resistant to further treatments. Twelve out of 24 subjects without cells with MDR phenotype in complete remission remained in this condition, six had a responsive relapse (without significant expression of P-170 in 5/6 patients) and six a resistant relapse. Four patients of this last group significantly expressed P-170. Our data indicate that the detection of scattered P-170 positive cells during complete remission might identify a subset of leukaemic patients with high risk of early and resistant relapse.     

Effect of ionizing radiation on cell-cycle progression and cyclin B1 expression in human melanoma cells

In the present study we investigated the effect of γ-irradiation (2.5 and 10 Gy) on cell-cycle progression of a human melanoma cell line, M14, characterized by a moderate radiosensitivity (SF2 = 0.5). Flow cytometric analysis showed a dose-dependent S-phase accumulation, which was detectable 8 hr after treatment with 2 and 5 Gy and was still persistent at 12 hr after 10 Gy exposure. Such a delay in S-phase was paralleled or followed by an accumulation of cells in G₂M, which was transient at the lowest radiation doses and still persistent at 72 hr after 10 Gy. Such an accumulation was, at least in part, due to a block in G₂-M transition, as demonstrated by mitotic index analysis. Bivariate flow cytometric analysis of DNA content and cyclin B₁ expression showed that, following 2 and 5 Gy, the fraction of cyclin B₁-expressing cells was superimposable upon that of G₂M cells. Conversely, in cells treated with 10 Gy, the fraction of cyclin B₁-expressing cells was half the G₂M cell fraction. Northern-blot analysis indicated that the radiation-induced decrease in cyclin B₁ protein expression was accompanied by a reduced cyclin B mRNA level. On the whole, our results indicate a direct inhibitory effect of 10 Gy irradiation on cyclin B₁ expression as a possible cause for the persistent G₂ block in irradiated M14 cells. © 1996 Wiley-Liss, Inc.     

Downstream health impacts of employment losses during the COVID-19 pandemic

Objectives The Canadian workforce has experienced significant employment losses during the COVID-19 pandemic, in part as a result of non-pharmaceutical interventions to slow COVID-19 transmission. Health consequences are likely to result from these job losses, but without historical precedent for the current economic shutdown they are challenging to plan for. Our study aimed to use population risk models to quantify potential downstream health impacts of the COVID-19 pandemic and inform public health planning to minimize future health burden.MethodsThe impact of COVID-19 job losses on future premature mortality and high-resource health care utilization (HRU) was estimated using an economic model of Canadian COVID-19 lockdowns and validated population risk models. Five-year excess premature mortality and HRU were estimated by age and sex to describe employment-related health consequences of COVID-19 lockdowns in the Canadian population.ResultsWith federal income supplementation like the Canadian Emergency Response Benefit, we estimate that each month of economic lockdown will result in 5.6 new high-resource health care system users (HRUs), and 4.1 excess premature deaths, per 100,000, over the next 5 years. These effects were concentrated in ages 45–64, and among males 18–34. Without income supplementation, the health consequences were approximately twice as great in terms of both HRUs and premature deaths.ConclusionEmployment losses associated with COVID-19 countermeasures may have downstream implications for health. Public health responses should consider financially vulnerable populations at high risk of downstream health outcomes.Supplementary InformationThe online version contains supplementary material available at 10.17269/s41997-021-00588-3.