Platelet dysfunction reversal with cold-stored vs room temperature-stored platelet transfusions.

ABSTRACT: Platelets are stored at room temperature for 5 to 7 days (room temperature-stored platelets [RSPs]). Because of frequent and severe shortages, the US Food and Drug Administration recently approved up to 14-day cold-stored platelets (CSPs) in plasma. However, the posttransfusion function of CSPs is unknown and it is unclear which donors are best suited to provide either RSPs or CSPs. In this study, we sought to evaluate the posttransfusion platelet function and its predictors for platelets stored for the maximum approved storage times (7-day RSPs and 14-day CSPs) in healthy volunteers on acetylsalicylic acid (ASA). We conducted a randomized crossover study in 10 healthy humans. Individuals donated 1 platelet unit, stored at either 22°C or 4°C based on randomization. Before transfusion, participants ingested ASA to inhibit endogenous platelets. Transfusion recipients were tested for platelet function and lipid mediators. Platelet units were tested for lipid mediators only. A second round of transfusion with the alternative product was followed by an identical testing sequence. RSPs reversed platelet inhibition significantly better in αIIbß3 integrin activation-dependent assays. In contrast, CSPs in recipients led to significantly more thrombin generation, which was independent of platelet microparticles. Lysophosphatidylcholine-O species levels predicted the procoagulant capacity of CSPs. In contrast, polyunsaturated fatty acid concentrations predicted the aggregation response of RSPs. In summary, we provide, to our knowledge, the first efficacy data of extended-stored CSPs in plasma. Our results suggest that identifying ideal RSP and CSP donors is possible, and pave the way for larger studies in the future. This trial is registered at www.ClinicalTrials.gov as #NCT0511102.

Practical Recommendations for the Manipulation of Kinase Inhibitor Formulations to Age-Appropriate Dosage Forms.

Over 75 kinase inhibitors (KIs) have been approved for the treatment of various cancers. KIs are orally administrated but mostly lack pediatric age-appropriate dosage forms or instructions for dose manipulation. This is highly problematic for clinical practice in pediatric oncology, as flexible oral formulations are essential to individually set dosages and to adjust it to a child's swallowability. Most KIs are poorly soluble, categorized in Biopharmaceutics Classification System (BCS) class II or IV, and improperly manipulating the KI formulation can alter pharmacokinetics and jeopardize KI drug safety and efficacy. Therefore, the goals of this review were to provide practical recommendations for manipulating the formulation of the 15 most frequently used KIs in pediatric oncology (i.e., bosutinib, cabozantinib, cobimetinib, crizotinib, dabrafenib, dasatinib, entrectinib, imatinib, larotrectinib, nilotinib, ponatinib, ruxolitinib, selumetinib, sunitinib and trametinib) based on available literature studies and fundamental drug characteristics and to establish a decision tool that supports decisions regarding formulation manipulation of solid oral dosages of KIs that have been or will be licensed (for adult and/or pediatric cancers) but are not included in this review.

Use of remdesivir for COVID-19 pneumonia in patients with advanced kidney disease: A retrospective multicenter study.

Background and objectives: Remdesivir, an antiviral drug routinely used in the treatment of COVID-19 has not yet received FDA approval for use in patients with advanced kidney disease defined as GFR < 30 mL/min/1.73 m2. There is concern that an excipient in Veklury (Gilead's proprietary name for remdesivir) called sulfobutylether-beta-cyclodextrin (SBECD), which is renally cleared, may accumulate and reach toxic levels in patients with advanced kidney disease. The aim of this study was to summarize characteristics and incidence of adverse events of chronic kidney disease (CKD) patients who received remdesivir during hospitalization.Design, setting, participants, and measurements.We retrospectively studied patients admitted to one of several hospitals of the Mayo Clinic Foundation with the diagnosis of COVID-19 pneumonia and CKD. Laboratory values were also measured when remdesivir was first administered and stopped. All analyses were performed in the overall patient group and three separate subgroups of patients with a GFR ≥ 15, a GFR < 15 and dialysis, and a GFR < 15 and no dialysis. Results: A total of 444 CKD patients who were admitted to the hospital with COVID-19 pneumonia between May 2020 and September 2021 were included. Information was collected on patient characteristics, hospitalization, and adverse events. In the overall cohort, median age was 72 years (Range: 21-100 years), 55.2 % of patients were male, and most (86.5 %) were Caucasian. CKD stage was 3 for 114 patients (25.7 %), 4 for 229 patients (51.6 %), and 5 for 101 patients (22.7 %). A total of 146 patients (32.9 %) were admitted to the ICU, 103 (23.2 %) died in the hospital, and 120 (27.0 %) were on dialysis. The proportion of patients with an adverse event did not differ dramatically between the GFR ≥ 15 (20.9 %), GFR < 15 and dialysis (30.2 %), and GFR < 15 and no dialysis (32.3 %) groups (P = 0.12). Conclusion: Our results suggest that the use of remdesivir in patients with very severe CKD is safe, even in those who are not on renal replacement therapy.

There and back again: the once and current developments in donor-derived platelet products for hemostatic therapy.

More than 100 years ago, Duke transfused whole blood to a patient with thrombocytopenia to raise the platelet count and prevent bleeding. Since then, platelet transfusions have undergone numerous modifications from whole blood-derived platelet-rich plasma to apheresis-derived platelet concentrates. The storage time and temperature have also changed. The mandate to store platelets for a maximum of 5 to 7 days at room temperature has been challenged by recent clinical trial data, ongoing difficulties with transfusion-transmitted infections, and recurring periods of shortages that were further exacerbated by the COVID-19 pandemic. Alternative platelet storage approaches are as old as the first platelet transfusions. Cold-stored platelets may offer increased storage times (days) and improved hemostatic potential at the expense of reduced circulation time. Frozen (cryopreserved) platelets extend the storage time to years but require storage at -80°C and thawing before transfusion. Lyophilized platelets can be powder-stored for years at room temperature and reconstituted within minutes in sterile water but are probably the least explored alternative platelet product to date. Finally, whole blood offers the hemostatic spectrum of all blood components but has challenges such as ABO incompatibility. We know more than ever before about the in vitro properties of these products, and clinical trial data are accumulating. The purpose of this review is to summarize the findings of recent preclinical and clinical studies on alternative, donor-derived platelet products.

Effect of bedside filtration on aggregates from cold-stored whole blood-derived platelet-rich plasma and apheresis platelet concentrates.

BACKGROUND: The current approach to manufacture cold-stored platelets (CSP) replicates that of room temperature-stored platelets (RSP). However, this production method is associated with aggregate formation in CSP, a major pitfall that leads to significant wastage. We hypothesized that isolating platelets from whole blood as platelet-rich plasma (PRP) and storing them at a lower concentration reduces aggregates and that conventional bedside transfusion filtration removes CSP aggregates. METHODS: We collected platelets from healthy humans by apheresis (AP) and by phlebotomy, from which we generated platelet-rich plasma (PRP). We split each AP and PRP platelets into two equal aliquots, storing one at 22°C (RT-PRP and RT-AP) and the other at 4°C (4C-PRP and 4C-AP). We evaluated platelets on day 0 and day 7 of storage. After storage, we measured platelet counts, aggregates, and other key characteristics before and after filtration by a bedside filter. RESULTS: After storage, the 4C-AP platelet counts decreased significantly. 4C-PRP preserved glucose better and prevented a significant increase in lactate contrary to 4C-AP. Filtration led to significantly lower platelet counts in both 4C-PRP and 4C-AP but not in their RT counterparts. Post filtration, we observed 50% fewer aggregates only in 4C-AP, whereas 4C-PRP showed an unexpected but significant increase in aggregates. Testing confirmed activation during storage but filtration did not further activate platelets. CONCLUSION: We provide evidence that 4C-PRP is an alternative to 4C-AP and that bedside filters reduce aggregates from 4C-AP. Further studies are needed to evaluate the hemostatic potential of 4C-PRP and the management of aggregates.

Warfarin therapy in atrial fibrillation: assessment of patient knowledge of risks and benefits.

Patients with atrial fibrillation are at an increased risk for stroke, and many benefits from anticoagulation. Despite the emergence of direct oral anticoagulants, many patients continue to rely on warfarin for their anticoagulation due to logistical, pharmacokinetic, clinical, or patient preference issues. Previous work has suggested that outcomes of warfarin therapy are related to patient education/knowledge. We assessed knowledge of indications, benefits, and complications of warfarin therapy in 99 randomly selected patients enrolled in the Warfarin Anticoagulation Clinic at the Mayo Clinic in Florida who were taking warfarin for non-valvular atrial fibrillation. Patients were labeled as 'knowledgeable' or 'not knowledgeable' regarding warfarin therapy according to the results of a cross-sectional questionnaire. The majority of patients in both the knowledgeable and not knowledgeable groups displayed understanding that they were taking warfarin for atrial fibrillation (valvular vs non-valvular atrial fibrillation was not an included answer choice). However, there was a clear lack of knowledge amongst patients with atrial fibrillation in both groups about their stroke risk while on and off warfarin, and their risk of major bleeding or adverse events related to their warfarin therapy. There was only a significant difference between the two groups regarding their knowledge of what increases or decreases the risk of bleeding while on warfarin. There was no major difference between the groups with regards to demographic and medical characteristics, except that 'not knowledgeable' patients tended to have more peripheral vascular disease, ulcer disease, and moderate-severe renal disease compared to 'knowledgeable' patients.

Changes and their possible causes in δ13C of dark-respired CO2 and its putative bulk and soluble sources during maize ontogeny.

The issues of whether, where, and to what extent carbon isotopic fractionations occur during respiration affect interpretations of plant functions that are important to many disciplines across the natural sciences. Studies of carbon isotopic fractionation during dark respiration in C3 plants have repeatedly shown respired CO2 to be (13)C enriched relative to its bulk leaf sources and (13)C depleted relative to its bulk root sources. Furthermore, two studies showed respired CO2 to become progressively (13)C enriched during leaf ontogeny and (13)C depleted during root ontogeny in C3 legumes. As such data on C4 plants are scarce and contradictory, we investigated apparent respiratory fractionations of carbon and their possible causes in different organs of maize plants during early ontogeny. As in the C3 plants, leaf-respired CO2 was (13)C enriched whereas root-respired CO2 was (13)C depleted relative to their putative sources. In contrast to the findings for C3 plants, however, not only root- but also leaf-respired CO2 became more (13)C depleted during ontogeny. Leaf-respired CO2 was highly (13)C enriched just after light-dark transition but the enrichment rapidly decreased over time in darkness. We conclude that (i) although carbon isotopic fractionations in C4 maize and leguminous C3 crop roots are similar, increasing phosphoenolpyruvate-carboxylase activity during maize ontogeny could have produced the contrast between the progressive (13)C depletion of maize leaf-respired CO2 and (13)C enrichment of C3 leaf-respired CO2 over time, and (ii) in both maize and C3 leaves, highly (13)C enriched leaf-respired CO2 at light-to-dark transition and its rapid decrease during darkness, together with the observed decrease in leaf malate content, may be the result of a transient effect of light-enhanced dark respiration.

Do Foley Catheters Adequately Drain the Bladder? Evidence from CT Imaging Studies.

INTRODUCTION: The Foley catheter has been widely assumed to be an effective means of draining the bladder. However, recent studies have brought into question its efficacy. The objective of our study is to further assess the adequacy of Foley catheter for complete drainage of the bladder. MATERIALS AND METHODS: Consecutive catheterized patients were identified from a retrospective review of contrast enhanced and non-contrast enhanced computed tomographic (CT) abdomen and pelvis studies completed from 7/1/2011-6/30/2012. Residual urine volume (RUV) was measured using 5mm axial CT sections as follows: The length (L) and width (W) of the bladder in the section with the greatest cross sectional area was combined with bladder height (H) as determined by multiplanar reformatted images in order to calculate RUV by applying the formula for the volume (V) of a sphere in a cube:V=(π/6)*(L*W*H). RESULTS: RUVs of 167 (mean age 67) consecutively catheterized men (n=72) and women (n=95) identified by CT abdomen and pelvis studies were calculated. The mean RUV was 13.2 mL (range: 0.0 mL-859.1 mL, standard deviation: 75.9 mL, margin of error at 95% confidence:11.6 mL). Four (2.4%) catheterized patients had RUVs of >50 mL, two of whom had an improperly placed catheter tip noted on their CT-reports. CONCLUSIONS: Previous studies have shown that up to 43% of catheterized patients had a RUV greater than 50 mL, suggesting inadequacy of bladder drainage via the Foley catheter. Our study indicated that the vast majority of patients with Foley catheters (97.6%), had adequately drained bladders with volumes of <50 mL.

Do Foley Catheters Adequately Drain the Bladder? Evidence from CT Imaging Studies

The Foley catheter has been widely assumed to be an effective means of draining the bladder. However, recent studies have brought into question its efficacy. The objective of our study is to further assess the adequacy of Foley catheter for complete drainage of the bladder.

Variation in δD values of a single, species-specific molecular biomarker: a study of miliacin throughout a field of broomcorn millet (Panicum miliaceum L.).

Compound-specific δD analyses of land plant-derived biomarkers preserved in lake sediments are gaining increasing interest in paleoclimatic studies because of their potential to record essential information on the climatic conditions that prevailed at the time of their synthesis. The accuracy of inferences about climate from these analyses could be better constrained with more study of the variability in the δD values of possible inputs at catchment scales. We measured the δD values of miliacin (olean-18-en-3ß-ol methyl ether) extracted from the seeds of millet plants collected in 21 stands spatially distributed in a field with visually heterogeneous soil organic matter contents. The use of a single molecular biomarker extracted from a single plant species eliminates the possibility of variability caused by differences in plant type. The δD values differed between plants by as much as 50‰ and the average δD values per stand differed from one another by a maximum of 30‰. Thus, the δD values of a single, species-specific biomarker can vary markedly among plants even within a similar climate. Differences in δD values within stands could be as high as between stands, suggesting that the δD values are not related to macroscale heterogeneities in soil organic matter content. In addition, δD values were unrelated to factors indicative of differences in environment such as plant height, seed weight or miliacin concentration. The average miliacin δD value was representative of the area sampled, however, since it was normally distributed (p < 0.05).

Peritonitis due to Blastobotrys proliferans in a patient undergoing continuous ambulatory peritoneal dialysis.

Blastobotrys proliferans is an ascomycetous yeast never previously reported as a human pathogen. Here we report a case of peritonitis due to Blastobotrys proliferans in a 46-year-old man undergoing peritoneal dialysis.

Proton affinity ladder for uridine and analogs: influence of the hydroxyl group on the sugar ring conformation.

A ladder of relative proton affinities (PA) for a series of modified uridines (e.g. araU, ddU, 5BrU, 5BrdU and 5IU) was established from competitive dissociations of proton-bound heterodimers using Cooks and co-workers' kinetic method. The studied heterodimers are constituted of a modified nucleoside and either an amino acid or a nucleoside with known PA value. These non-covalent heterodimers were prepared under electrospray conditions to be selected and dissociated into the ion-trap analyzer. These results allowed our PA ladder of uridine and deoxyuridine analogs substituted at the C-5 position in the uracil ring to be extended. From this scale, it was showed that the substitution of hydrogen atom at the C-2' position in the sugar ring by a hydroxyl group involves a decrease of about 7 kJ mol(-1). The experimental values for U, 5MeU, dU, 5MedU, ddU and araU are consistent with those obtained by DFT calculations (B3P86/6-31+G//B3LYP/6-31G(.)). Several neutral and protonated conformations of these compounds were considered, in particular the ring conformation of furanose and the orientation of the base with respect to the sugar ring. These calculated results showed the influence of sugar substituent on the conformation of the neutral form of theses nucleosides. However, the most stable protonated structure is the same for all the studied nucleosides except for araU, where the position of the anti 2'-OH group imposes a specific conformation.

Synthesis of 2-(N-Acetylamino)-2-deoxy-C-glucopyranosyl nucleosides as potential inhibitors of chitin synthases.

The C-glucopyranosyl nucleosides (1-4) containing the N-acetyl glucosaminyl and uridine units have been synthesized as nonhydrolyzable substrate analogues of UDP-GlcNAc aimed to inhibit the chitin synthases. The key intermediate, 4-(2'-(N-acetylamino)-3', 4',6'-tri-O-benzyl-2'-deoxy-alpha-D-glucopyranosyl)but-2-enoic acid (5), was prepared from the perbenzylated (N-acetylamino)-alpha-C-allylglucoside (7), by successive oxidative cleavage, Wittig olefination, and ester deprotection. The coupling of the acid 5 with the hydroxyl or amine function of the uridine derivatives (6a or 6b) afforded, respectively, the ester 12 and amide 14. The dihydroxylation of the conjugated double bond in ester 12 or amide 14 was better achieved with osmium tetraoxide/barium chlorate, leading to the expected diols 13 and 15 as a mixture of two diastereoisomers. The desired compounds 1-4 were obtained after catalytic hydrogenation of compounds 12-15.

The nature and amount of support college-age adolescents request and receive from parents.

While older adolescents appear to spend less time with their families, some research has shown parents to be the preferred source of support. The purpose of this study is to determine if adolescents receive instrumental and emotional support as requested from each parent, and if the support they receive is perceived as helpful. Study participants included 206 two-year college students (39% males and 61% female) with a mean age of 18.9 years. A mother/father-adolescent interaction inventory was used to measure perceived parental support and the "Who Helps With Your Problems?" inventory was used to measure received parental support within a two-week period. Results indicated that adolescents received support almost every time it was requested, although few requests were made. Gender differences were present for the type of support received, where females received significantly more emotional than instrumental support from both mothers (t = 3.88, p < .001) and fathers (t = 1.98, p < .05). Additionally, a positive correlation was found between perceived and received instrumental and emotional support from mothers (r = .33 and r = .27, p < .001 and p < .10, respectively) and fathers (r = .33 and r = .37, P < .001), respectively) for females only. Possible reasons for gender differences may be due to the roles society has ascribed to males and females. Recommendations for future research are discussed.

Dopaminergic influence on the cardiovascular response to exercise in normotensive and hypertensive subjects.

Fourteen subjects (normotensive, hypertensive) were studied at the Vargas Hospital of Caracas. They were treated with placebo (2 periods), domperidone, a peripheral dopaminergic blocker, at the daily oral dose of 40 mg, and metoclopramide, a central and peripheral dopaminergic blocker, at the daily oral dose of 40 mg. All placebo and active drug periods lasted 1 week. Cardiovascular hemodynamic parameters (blood pressure, heart rate) were measured before, during and after submitting subjects to treadmill exercise according to the Bruce's protocol. Metoclopramide decreased significantly heart rate before and during exercise stress and systolic blood pressure during stage 1 exercise in normotensive subjects. Domperidone decreased significantly heart rate before and during exercise stress, and systolic blood pressure during stage 3 exercise in hypertensive subjects. Neither heart rate nor blood pressure were changed significantly after 8 minutes resting period post exercise. Our results suggest the existence of an excitatory modulatory influence of dopaminergic influence during exercise over the sympathetic activity.

Synthesis and physicochemical properties of oligonucleotides built with either alpha-L or beta-L nucleotides units and covalently linked to an acridine derivative.

Modified deoxynucleosides 2'-deoxy-beta-L-uridine, beta-L-thymidine, alpha-L-thymidine, 2'-deoxy-beta-L-adenosine and 2'-deoxy-alpha-L-adenosine were synthesized and assembled as homooligomers, respectively: octa-beta-L-deoxyuridylates, octa beta-L and alpha-L-thymidylates and tetra beta-L and alpha-L-deoxyadenylates. These unnatural oligomers were then substituted with an acridine derivative. The binding studies of these modified oligonucleotides with D-ribo- and D-deoxyribopolynucleotides were carried out by absorption spectroscopy. While beta-L-d(Up)8m5Acr, beta-L-(Tp)8m5Acr, alpha-L-(Tp)8m5Acr did not interact with poly(rA) and poly(dA), beta-L-d(Ap)4m5Acr and alpha-L-d(Ap)4m5Acr did form double and triple helices with poly(rU) and poly(dT), respectively. Their stability towards nuclease digestion was studied through comparison with that of octa-beta-D-thymidylate and tetra beta-D-deoxyadenylate covalently linked to an acridine derivative. One endonuclease (nuclease P1 from Penicillium citrinum) and two exonucleases (a 3'-exonuclease from Crotalus durissus venom and a 5'-exonuclease extracted from calf thymus) were employed. beta-L- and alpha-L-oligomers demonstrate a high resistance toward nuclease digestion.