Prolonged SARS-CoV-2 Infection in Patients Receiving Anti-CD20 Monoclonal Antibodies: A Diagnostic Challenged by Negative Nasopharyngeal RT-PCR and Successful Treatment with COVID-19 High-Titer Convalescent Plasma

We highlighted in this current paper similar prolonged respiratory presentation with COVID-19 pneumonia in four severely immunocompromised patients currently being treated with anti-CD20 monoclonal antibodies (mAbs), such as ocrelizumab and rituximab, for multiple sclerosis or rheumatoid polyarthritis. Real-time reverse transcription-polymerase chain reaction on a nasopharyngeal swab specimen was negative in all patients. SARS-CoV-2 infection was confirmed from bronchoalveolar lavage fluid. A high titer of post-vaccine COVID-19 convalescent plasma was administered with complete recovery in all patients.

Correlation between magnetic resonance, X-ray imaging alterations and histological changes in an ovine model of age-related disc degeneration

Sheep are one of the many animal models used to investigate the pathophysiology of disc degeneration and the regenerative strategies for intervertebral disc (IVD) disease. To date, few studies have thoroughly explored ageing of ovine lumbar IVDs. Hence, the objective of the present study was to concomitantly assess the development of spontaneous age-related lumbar IVD degeneration in sheep using X-ray, magnetic resonance imaging (MRI) as well as histological analyses. 8 young ewes (< 48 months old) and 4 skeletally mature ewes (> 48 months old) were included. Disc height, Pfirrmann and modified Pfirrmann grades as well as T2-wsi and T2 times were assessed by X-ray and MRI. The modified Boos score was also determined using histology sections. Pfirrmann (2 to 3) and modified Pfirrmann (2 to 4) grades as well as Boos scores (7 to 13) gradually increased with ageing, while T2-weighted signal intensity (1.18 to 0.75), T2 relaxation time (114.36 to 70.65 ms) and disc height (4.1 to 3.2 mm) decreased significantly. All the imaging modalities strongly correlated with the histology (p < 0.0001). The present study described the suitability of sheep as a model of age-related IVD degeneration by correlation of histological tissue alterations with the changes observed using X-ray and MRI. Given the structural similarities with humans, the study demonstrated that sheep warrant being considered as a pertinent animal model to investigate IVD regenerative strategies without induction of degeneration.

Degenerative lumbar disc disease: in vivo data support the rationale for the selection of appropriate animal models

Since low-back pain is increasing in ageing populations, current research efforts are focused on obtaining a better understanding of the pathophysiology of intervertebral disc degeneration and on developing new therapeutic strategies. This requires adequate and clinically relevant models of the disease process. Ex vivo models can provide insights into isolated aspects of the degenerative/regenerative processes involved; although, ultimately, in vivo models are needed for preclinical translational studies. Such models have been developed in numerous animal species with significant variations in size and disc physiology and their number is considerable. Importantly, the choice of the model has to be tailored to the aim of the study. Given the number of available options, it is important to have a good understanding of the various models of disc degeneration and to be fully aware of their advantages and limitations. After comparing the anatomy and histology of intervertebral discs in animals and humans, the present study provides an overview of the different models of in vivo disc degeneration. It also provides a comprehensive guide with suggested criteria to select the most appropriate animal model in a question-driven manner.

Pharmacokinetic (PK) and tolerance profiles of oral tegafur/uracil (UFT) given as three versus two daily intakes

12013

Background: This phase II randomized bioequivalence cross-over study compared the tolerance and PK profiles of oral UFT (tegafur-uracil) given as 3 daily intakes (tid, usual schedule) to that obtained with 2 daily intakes (bid). Methods: Twenty-one metastatic colorectal cancer patients were enrolled (16 men, 5 women ; mean age 64, extremes 42–79 ; ECOG PS ≤ 1). Tegafur-uracil (300 mg/m2/d) and leucovorin (90 mg/d) were given for 2 consecutive four-week cycles separated by one rest week. Patients were randomized for receiving 1st cycle either tid (arm A, 12 patients) or bid (arm B, 9 patients). For each schedule, PK was evaluated at steady state, over 24 h. Plasma concentrations of tegafur, uracil and fluorouracil (FU) were analyzed by HPLC. Results: Analysis of tolerance (digestive toxicity mainly, OMS grade) showed a tendency (p = 0.08) for a greater toxicity with the bid schedule (29% grade 2, 14% grade 3) relative to tid (24% grade 2 only). Although daily doses were similar, FU and uracil AUC0–24h were respectively 1.8 and 2.0-fold higher for bid as compared to tid (95% CI were 1.5–2.1 and 1.6–2.6, respectively, p < 0.0001). For tegafur, the 1.2-fold difference was of borderline significance (p = 0.057). The greater the FU AUC0–24h, the higher the toxicity intensity (p = 0.044). Analysis of systemic exposure with respect to daily time revealed that FU (p < 0.01) and uracil (p < 0.03) AUC corresponding to the morning intake were significantly higher than those corresponding to the afternoon or evening intakes, with AUC ratio as high as 1.6 for FU and 2.9 for uracil. Such a circadian influence was not observed for tegafur. Conclusions: To reach bioequivalence, bid tegafur-uracil administration will require lower doses than those given tid. The circadian variability observed for FU and uracil PK concords with that previously reported for dihydropyrimidine deshydrogenase activity.

No significant financial relationships to disclose.