Anti-PF4 VITT antibodies are oligoclonal and variably inhibited by heparin.

BACKGROUND: COVID-19 vaccines have been associated with a rare thrombotic and thrombocytopenic reaction, Vaccine-induced immune thrombotic thrombocytopenia (VITT) characterized by platelet-activating anti-PF4 antibodies. This study sought to assess clonality of VITT antibodies and evaluate their characteristics in antigen-based and functional platelet studies. METHODS: Anti-PF4 antibodies were isolated from five patients with VITT secondary to ChAdOx1 nCoV-19 (n=1) or Ad26.COV2.S (n=4) vaccination. For comparative studies with heparin-induced thrombocytopenia (HIT), anti-PF4 antibodies were isolated from one patient with spontaneous HIT, another with "classical" HIT, and two patients with non-pathogenic (non-platelet activating) anti-PF4 antibodies. Isolated antibodies were subject to ELISA and functional testing, and mass spectrometric evaluation for clonality determination. RESULTS: All five VITT patients had oligoclonal anti-PF4 antibodies (3 monoclonal, one bi- and one tri-clonal antibodies), while HIT anti-PF4 antibodies were polyclonal. Notably, like VITT antibodies, anti-PF4 antibodies from a spontaneous HIT patient were monoclonal. The techniques employed did not detect non-pathogenic anti-PF4 antibodies. The ChAdOx1 nCoV-19-associated VITT patient made an excellent recovery with heparin treatment. In vitro studies demonstrated strong inhibition of VITT antibody-induced platelet activation with therapeutic concentrations of heparin in this and one Ad26.COV2.S-associated VITT patient. Oligoclonal VITT antibodies with persistent platelet-activating potential were detected at 6 and 10 weeks after acute presentation in two patients tested. Two of the 5 VITT patients had recurrence of thrombocytopenia and one patient had focal seizures several weeks after acute presentation. CONCLUSION: Oligoclonal anti-PF4 antibodies mediate VITT. Heparin use in VITT needs to be further studied.

Neural correlates of cognitive variability in childhood autism and relation to heterogeneity in decision-making dynamics.

Heterogeneity in cognitive and academic abilities is a prominent feature of autism spectrum disorder (ASD), yet little is known about its underlying causes. Here we combine functional brain imaging during numerical problem-solving with hierarchical drift-diffusion models of behavior and standardized measures of numerical abilities to investigate neural mechanisms underlying cognitive variability in children with ASD, and their IQ-matched Typically Developing (TD) peers. Although the two groups showed similar levels of brain activation, the relation to individual abilities differed markedly in ventral temporal-occipital, parietal and prefrontal regions important for numerical cognition: children with ASD showed a positive correlation between functional brain activation and numerical abilities, whereas TD children showed the opposite pattern. Despite similar accuracy and response times, decision thresholds were significantly higher in the ASD group, suggesting greater evidence required for problem-solving. Critically, the relationship between individual abilities and engagement of prefrontal control systems anchored in the anterior insula was differentially moderated by decision threshold in subgroups of children with ASD. Our findings uncover novel cognitive and neural sources of variability in academically-relevant cognitive skills in ASD and suggest that multilevel measures and latent decision-making dynamics can aid in characterization of cognitive variability and heterogeneity in neurodevelopmental disorders.

Synthesis and electrochemical characterization of electroactive IoNanofluids with high dielectric constants from hydrated ferrous sulphate.

An iron oxide based-electroactive IoNanofluid with a high dielectric constant, high stability and low viscosity was synthesized from ferrous sulphate heptahydrate via a facile microwave assisted one-step route in 1-butyl-4-methylpyridinium chloride. The IoNanofluid exhibited CE coupled faradaic redox reactions involving reversible chemical reaction and reversible electron transfer steps. A transition from diffusion controlled to surface controlled capacitive processes was observed at varying scan rates. The efficiency of the charge-discharge process was greater than 94% even after 100 cycles.

Intravenous immunoglobulin as an adjunct therapy in persisting heparin-induced thrombocytopenia.

Heparin induced thrombocytopenia (HIT) is a serious adverse drug reaction caused by transient antibodies against platelet factor 4 (PF4)/heparin complexes, resulting in platelet activation and potentially fatal arterial and/or venous thrombosis. Most cases of HIT respond to cessation of heparin and administration of an alternative non-heparin anticoagulant, but there are cases of persisting HIT, defined as thrombocytopenia due to platelet activation/consumption for greater than seven days despite standard therapy. These patients remain at high risk for thrombotic events, which may result in limb-loss and mortality. Intravenous immunoglobulin (IVIg) has been proposed as an adjunct therapy for these refractory cases based on its ability to saturate FcγRIIa receptors on platelets, thus preventing HIT antibody binding and platelet activation. We describe 2 cases of persisting HIT (strongly positive antigen and functional assays, and persisting thrombocytopenia >7 days) with rapid clinical response to IVIg. We performed in-vitro experiments to support IVIg response. Healthy donor platelets (1 × 10e6) were treated with PF4 (3.75 µg/mL) for 20 min followed by 1-hour incubation with patients' sera. Platelet activation with and without addition of IVIg (levels equivalent to those reached in a patient after treatment with 2 gm/Kg) was evaluated in the PF4-dependent P-selectin expression assay (PEA). A significantly decreased platelet activation was demonstrated after the addition of IVIg to both patient samples, which correlated well with the rapid clinical response that each patient experienced. Thus, our study supports the use of IVIg as an adjunct therapy for persisting HIT.

Theoretical Probing of Weak Anion-Cation Interactions in Certain Pyridinium-Based Ionic Liquid Ion Pairs and the Application of Molecular Electrostatic Potential in Their Ionic Crystal Density Determination: A Comparative Study Using Density Functional Approach.

A comprehensive study on the structure, nature of interaction, and properties of six ionic pairs of 1-butylpyridinium and 1-butyl-4-methylpyridinium cations in combination with tetrafluoroborate (BF4-), chloride (Cl-), and bromide (Br-) anions have been carried out using density functional theory (DFT). The anion-cation interaction energy (ΔEint), thermochemistry values, theoretical band gap, molecular orbital energy order, DFT-based chemical activity descriptors [chemical potential (µ), chemical hardness (η), and electrophilicity index (ω)], and distribution of density of states (DOS) of these ion pairs were investigated. The ascendancy of the -CH3 substituent at the fourth position of the 1-butylpyridinium cation ring on the values of ΔEint, theoretical band gap and chemical activity descriptors was evaluated. The ΔEint values were negative for all six ion pairs and were highest for Cl- containing ion pairs. The theoretical band gap value after -CH3 substitution increased from 3.78 to 3.96 eV (for Cl-) and from 2.74 to 2.88 eV (for Br-) and decreased from 4.9 to 4.89 eV (for BF4-). Ion pairs of BF4- were more susceptible to charge transfer processes as inferred from their significantly high η values and comparatively small difference in ω value after -CH3 substitution. The change in η and µ values due to the -CH3 substituent is negligibly small in all cases except for the ion pairs of Cl-. Critical-point (CP) analyses were carried out to investigate the AIM topological parameters at the interionic bond critical points (BCPs). The RDG isosurface analysis indicated that the anion-cation interaction was dominated by strong Hcat···Xani and Ccat···Xani interactions in ion pairs of Cl- and Br- whereas a weak van der Waal's effect dominated in ion pairs of BF4-. The molecular electrostatic potential (MESP)-based parameter ΔΔVmin measuring the anion-cation interaction strength showed a good linear correlation with ΔEint for all 1-butylpyridinium ion pairs (R2 = 0.9918). The ionic crystal density values calculated by using DFT-based MESP showed only slight variations from experimentally reported values.

Suspected Hepadnavirus Association with a Hepatocellular Carcinoma in a Black-Tailed Prairie Dog (Cynomys ludovicianus).

Hepatocellular carcinomas are the most commonly reported neoplasm of black-tailed prairie dogs (Cynomys ludovicianus). In several other closely related Sciuridae species, infection with species-specific hepadnaviruses is associated with the development of these tumours, but such a hepadnavirus has not yet been identified in any prairie dog species, although its presence has been hypothesized previously. An adult prairie dog was humanely destroyed due to progressive illness and the identification of a cranial abdominal mass that was determined on histopathology to be a hepatocellular carcinoma. Deep sequencing of the tumour tissue identified the presence of a hepadnavirus, similar in its genetic structure to woodchuck hepatitis virus. Electron microscopy showed the presence of viral particles similar in structure to other hepadnaviral particles. This report suggests that a hepadnavirus may be associated with the development of hepatocellular carcinomas in the prairie dog.

Observation of interference between two distinct autoionizing states in dissociative photoionization of H2.

Dissociative photoionization (DPI) of randomly oriented H(2) molecules has been studied using linearly polarized synchrotron radiation at selected photon energies of 31, 33, and 35 eV. Large amplitude oscillations in the photoelectron asymmetry parameter ß, as a function of electron energy, have been observed. The phase of these ß oscillations are in excellent agreement with the results of recent close coupling calculations [Fernández and Martín, New J. Phys. 11, 043020 (2009)]. We show that the oscillations are the signature of interferences between the 1Q(1) (1)Σ(u)(+) and 1Q(2) (1)Π(u) doubly excited states decaying at different internuclear distances. The oscillations thus provide information about the classical paths followed by the nuclei. The presence of such oscillations is predicted to be a general phenomenon in DPI.

Nutrients and certain lipid soluble bioactive components in dehusked whole grains (gota) and dehusked splits (dhal) from pigeon pea (Cajanus cajan) and their cooking characteristics.

The nutritional quality of dehusked whole grains (gota) and dehusked splits (dhal) in red and white varieties of pigeon pea regarding proximate composition and certain lipid-soluble bioactive components was investigated. A decrease in fat and crude fiber was noticed when gota was converted to dhal. The lipid profile of gota and dhal from red and white husk pigeon pea types indicated that essential fatty acids were greater in gota than in their respective dhals. Gota from white husk variety contained more tocopherols than the red variety. Dhal contained less tocopherols than gota. A decrease in the content of gamma and alpha tocopherols, vitamin E activity and total antioxidant activity also indicates loss of bioactive components on splitting gota into dhal. Cooking time and dispersed solids on cooking indicated good cooking quality of gotta. The results indicated the nutritional superiority of gota over dhal and its similarity with dhal in cooking characteristics.

Use of the haematopoietic progenitor cell parameter in optimizing timing of peripheral blood stem cell harvest.

BACKGROUND AND OBJECTIVES: Timing of peripheral blood stem cell (PBSC) harvest is typically based on quantification of peripheral blood (PB) CD34+ cells. CD34 enumeration is expensive, requires expertise and takes a minimum of 1-2 h to perform. The Sysmex XE2100 is an automated haematology analyser that can rapidly and inexpensively identify haematopoietic progenitor cell (HPC) populations in PB. The aim of this study was to examine if HPC can be used to optimize timing of PBSC harvest. MATERIALS AND METHODS: White blood cell (WBC), HPC and CD34 counts were determined in a total of 60 mobilized donors. Data were analysed to examine the utility of WBC and HPC counts in predicting preharvest CD34+ counts. RESULTS: In adults presenting for autologous collection, a PB HPC threshold of > 30/microl predicts a preharvest CD34+ count of > 20/microl with sensitivity of 86% and positive predictive value (PPV) of 100%. Among paediatric patients with a diagnosis of neuroblastoma, an HPC threshold of > 16/microl yielded sensitivity and PPV of 100%, while in children with other diagnoses, an HPC cut-off of > 44/microl yielded sensitivity and PPV of 67% and 100%, respectively. Eighty per cent of adequately mobilized allogeneic donors were identified using an HPC threshold > 15/microl, with a PPV of 100%. PB WBC can also aid in predicting CD34 counts in most patient groups, albeit with lower sensitivity than HPC. CONCLUSION: By virtue of being a sensitive and accurate predictor of preharvest CD34+ counts, our data support the use of the HPC parameter in optimizing the timing of PBSC harvest.

Introduction of an early pregnancy assessment unit: audit on the first 6 months of service.

BACKGROUND: Women experiencing bleeding in early pregnancy suffer considerable anxiety. Waiting for a considerable time for a diagnosis adds to their grievance. Early Pregnancy Assessment Unit (EPAU) is a dedicated service that provides quick and easy accessibility to diagnosis, treatment and support service. AIM: To monitor the first 6 months of the EPAU service in the Rotunda Hospital, to identify its shortcomings, so that we can ensure effective EPAU care in future. METHODS: A retrospective audit between July and December 2002 was performed. RESULTS: A majority of patients (83.4%) were self-referrals. All patients were seen between 1 and 3 h. In the miscarriage group, 218/278 (78.4%) was managed surgically by evacuation and a further 60/278 (21.6%) received conservative or medical treatment. Among 13 ectopic pregnancies, 5/13 (39%) had laparoscopic management. CONCLUSION: This clinic has enabled us to manage early pregnancy bleeding in an effective manner within a satisfactory time period. The high surgical intervention rate for miscarriages is highlighted to support the need for greater emphasis on medical and expectant management.

Thymoma: a pathological study of 50 cases.

BACKGROUND: A combination of epithelial cells and lymphocytes results in a varied histomorphology of thymomas and consequent varied classification systems. AIM: To correlate the Marino and Muller-Hermelink (MMH) classification with the invasive behaviour of thymomas. SETTING AND DESIGN: Retrospective analysis. MATERIALS AND METHOD: Thymomas encountered in the past 21 years were re-classified with the MMH classification and correlated with Masaoka's staging and clinical presentation. RESULTS: The thymomas formed 91% of the primary thymic epithelial tumours. Predominantly cortical thymomas (n=21) and cortical thymomas (n=22) were the common subtypes and 60% and 77% of these, respectively, were in stages II or III. Cystic change, necrosis or haemorrhage played no role in predicting invasive behaviour. Cortical epithelium correlated well with the presence of para-thymic syndromes, especially myasthenia gravis. CONCLUSION: MMH classification is easy to apply. Cortical thymomas in stage I should be followed up for possible recurrence.

T-level downstaging and complete pathologic response after preoperative chemoradiation for advanced rectal cancer result in decreased recurrence and improved disease-free survival.

PURPOSE: Preoperative chemoradiation therapy is used widely in the treatment of rectal cancer. The predictive value of response to neoadjuvant remains uncertain. We retrospectively evaluated the impact of response to preoperative and, specifically, of T-level downstaging, nodal downstaging, and complete pathologic response after chemoradiation therapy on oncologic outcome of patients with locally advanced rectal cancer. METHODS: There were 88 patients with ultrasound Stage T3/T4 midrectal (n = 37) and low rectal (n = 51) cancers (63 males; mean age 62.6 years). All patients were treated by preoperative 5-fluorouracil-based chemotherapy and pelvic radiation followed by surgical resection in six weeks or longer (56 sphincter-preserving resections). RESULTS: T-level downstaging after neoadjuvant treatment was demonstrated in 36 (41 percent) of 88 patients, and complete pathologic response was observed in 16 (18 percent) of the 88. Of the 42 patients with ultrasound-positive nodes, 27 had no evidence of nodal involvement on pathologic evaluation (64 percent). The overall response rate (T-level downstaging or nodal downstaging) was 51 percent. At a median follow-up of 33 months, 86.4 percent of patients were alive. The overall recurrence rate was 10.2 percent (three patients had local and six had metastatic recurrences). Patients with T-level downstaging and complete pathologic response were characterized by significantly better disease-free survival (P = 0.03, P = 0.04) and better overall survival (P = 0.07, P = 0.08), according to Wilcoxon's test comparing Kaplan-Meier survival curves. None of the patients with complete pathologic response developed recurrence or died during the follow-up period. CONCLUSION: T-level downstaging and complete pathologic response after preoperative chemoradiation therapy followed by definitive surgical resection for advanced rectal cancer resulted in decreased recurrence and improved disease-free survival. Advanced rectal cancers that undergo T-level downstaging and complete pathologic response after chemoradiation therapy may represent subgroups that are characterized by better biologic behavior.

High prevalence of microcytic anaemia in Omani children: a prospective study.

Iron deficiency is a common cause of microcytic anaemia. However, a high prevalence of haemoglobinopathies in the Arab population makes differential diagnosis difficult. This prospective study of anaemia in children attending a regional hospital in the Sultanate of Oman looked at the prevalence and causes of anaemia in 256 children, 153 in the age group 3-5 years (group A) and 103 in the age group 10-12 years (group B). Of the children studied, 45.1% in group A and 37.9% in group B were anaemic according to WHO criteria. All the anaemic children had low mean corpuscular haemoglobin and 75% showed microcytosis. Serum ferritin levels were normal and glucose-6-phosphate dehydrogenase deficiency did not contribute to the anaemia. The microcytosis and microcytic anaemia in the study population could be attributed to the alpha-thalassaemia trait which is highly prevalent in Oman. The information is of value in any country where there is a significant prevalence of alpha-thalassaemia genes because these can confound the diagnosis of iron deficiency.

Reconstruction of rectovaginal fistula with sphincter disruption by combining rectal mucosal advancement flap and anal sphincteroplasty.

PURPOSE: This study evaluated the effectiveness of combining advancement flap with sphincteroplasty in patients symptomatic with rectovaginal fistula and anal sphincter disruption. METHODS: Twenty patients with rectovaginal fistulas and anal sphincter disruptions after vaginal deliveries underwent combined rectal mucosal advancement flap and anal sphincteroplasty between July 1986 and July 1993. The mean age of the patients was 30 (range, 18-40) years and the mean duration of symptoms was 54.8 weeks (range, 7 weeks to 6 years). In addition to mucosal advancement flap repair, 13 patients underwent two-layer repair of anal sphincters (with reapproximation of the puborectalis in 8 of the patients); 6 patients underwent one-layer overlap repair of anal sphincters (with reapproximation of the puborectalis in 2 of the patients); and 1 patient underwent reapproximation of internal anal sphincter alone because squeeze pressures were adequate, as determined by anal manometry. RESULTS: Postoperatively, vaginal discharge of stool and flatus was eliminated entirely in all 20 patients. Perfect anal continence of stool and flatus was restored in 14 patients (70 percent). Incontinence was improved but not eliminated in six patients (4 incontinent to liquid stool and 2 to flatus), and two patients required perineal pads. Subjectively, 19 patients (95 percent) reported the result as excellent or good. There were no complications. CONCLUSION: The combination of mucosal advancement flap and anal sphincteroplasty is a safe and highly effective procedure for correcting rectovaginal fistula with sphincter disruption after obstetrical injuries.

Robust analysis of within-unit variances in repeated measurement experiments.

The objective of some experiments is to compare the within-unit variances of two or more treatments, products, or techniques. In this situation, a repeated measurement design involving a random effects model, with possibly heterogeneous variances, is appropriate. Under the assumption that the random errors have a normal or a multivariate t-distribution, this design was analyzed in Chinchilli, Esinshart, and Miller (1995, Biometrics 51, 215-216). However, the resulting methodology is quite vulnerable to skewness and outliers. We propose two distribution-free procedures that are quite robust for balanced designs when the number of repeated measurements is the same for all units and for all treatments. We then show how these procedures are modified to handle unbalanced situations. We illustrate the methodology with an example from a trial comparing serum cholesterol measurements from a routine laboratory analyzer with those of a standardized method.

Expression of Chinese hamster cAMP-dependent protein kinase in Escherichia coli results in growth inhibition of bacterial cells: a model system for the rapid screening of mutant type I regulatory subunits.

The regulatory and catalytic subunits of cAMP-dependent protein kinase (PKA) were coexpressed within the same bacterial cell using a polycistronic bacterial T7 expression vector encoding Chinese hamster cDNAs for the type I regulatory (RI) and catalytic alpha (C alpha) subunits of PKA. Basal expression of active RI/C alpha holoenzyme in the BL21(DE3) strain of Escherichia coli caused severe growth inhibition resulting in extremely small colony size. Several lines of evidence demonstrate that this growth inhibition requires active PKA subunits and cAMP: (i) this phenotype is dependent on cAMP since it is not seen in a strain lacking adenylyl cyclase activity, but the growth rate of these transformants is slower when exogenous cAMP is added; (ii) normal growth occurs when wild-type RI cDNA is replaced by a mutant RI cDNA encoding a RI protein with reduced cAMP binding; and (iii) the growth-inhibited phenotype of the transformed BL21(DE3) cells requires soluble, active C alpha protein. Holoenzyme expressed in bacteria is activated by cAMP, which stimulates phosphorylation of an endogenous 50-kDa protein that is missing in four host mutants selected for normal growth after transformation with PKA holoenzyme. A mutant RI cDNA library was generated by PCR random mutagenesis and screened by polycistronic expression in BL21(DE3) cells. The RI cDNA sequence from one revertant has base-pair substitutions creating two amino acid substitutions within the cAMP binding sites. The coexpression of the RI/C alpha subunits in BL21(DE3) bacterial cells provides a system for rapidly selecting mutations in the RI subunits of PKA.

Abdominal colon and rectal operations in the elderly.

Sixty-seven abdominal operations for colon and rectal disorders were performed on 56 patients 80 years of age or older from January 1, 1984 to June 30, 1989. Nine patients required multiple operations. Sixty-two procedures (92 percent) were performed on patients in their ninth decade; two operations were performed on patients 95 years of age or older. Forty-five patients (80 percent) were operated upon for carcinoma. Operations included segmental colectomy (33 patients), low anterior resection (12 patients), total abdominal colectomy (3 patients) and abdominoperineal resection (2 patients). Forty patients were classified as ASA Class III; the majority were monitored in the surgical intensive care unit for a mean of 2.84 days. Thirty patients were monitored with arterial catheters and 21 with central invasive monitoring. Operative mortality was 7 percent (4 patients). Two patients died from diffuse carcinomatosis; one patient had a fatal myocardial infarction. The final death occurred from multisystem organ failure following anastomotic dehiscence. Twenty-seven operations were performed without postoperative complications; 18 operations were followed by a single minor complication. The average hospital stay was 18.96 days. All patients were admitted from home. Thirty-three returned home postoperatively; 16 were discharged to an extended care facility. In conclusion, elderly patients with colon and rectal disorders can be operated upon with acceptable morbidity and mortality. Age alone should not interdict surgical therapy.

Squamous-cell carcinoma of the anal canal: management with combined chemo-radiation therapy.

Twenty patients with squamous-cell carcinoma of the anal canal received combined chemo-radiation therapy as their primary treatment. There were 18 women and two men with a mean age of 63 years (range, 34-91 years). The mean follow-up was 34 months (range, 6-62 months). Anal margin cancers and adenocarcinomas were excluded. Fourteen of 20 patients treated had a complete response. There were six local failures: three with residual disease at the end of treatment and three with recurrent disease at a later date. Of the three with residual disease, one underwent abdominoperineal resection and two received salvage therapy (one with chemo-radiation and one with radiation alone). All three patients with recurrent disease were treated with abdominoperineal resection. All six were disease free at the end of the study. Of the 14 patients with complete local response, one presented with liver metastases 19 months later. Sixteen patients (80 percent) were alive at the end of the study, and 19 patients (95 percent) had no evidence of disease. These data add support for salvage therapy in the treatment of patients with residual disease following initial chemo-radiation therapy. Salvage options for patients with squamous-cell carcinoma of the anus who fail the Nigro protocol will be discussed.