Amelioration of established Sendai viral pneumonia in the nude mouse using a monoclonal antibody to the virus fusion protein.

The pathological effect of parainfluenza type I (Sendai virus) is known to be a bronchopneumonia, which becomes a chronic pneumonia in the immunodeficient athymic (nude) mouse. The severity of this established chronic pneumonia can be dramatically altered by providing the nude mouse with humoral monoclonal antibodies which are neutralizing, and are directed against the fusion protein, of the virus. The alveolitis, which is a significant part of the pathology, is suppressed due to a reduction (greater than 90%) in the number of virus-infected alveolar macrophages present in the alveoli. This clearly identifies the infected alveolar macrophage as the primary effector cell in the pathogenesis of alveolitis caused by parainfluenza virus type I. The implications of using virus-neutralizing monoclonal antibodies, which have little immunomodulatory toxicity, in the treatment of viral pneumonias are discussed.     

Antibody and cytokine responses to the cilium-associated respiratory bacillus in BALB/c and C57BL/6 mice

The cilium-associated respiratory (CAR) bacillus is a gram-negative, gliding bacterium that causes persistent respiratory tract infections in rodents despite histologic and serologic evidence of a marked immune response. To assess humoral immunity and cytokine responses in CAR bacillus disease, 6-week-old female BALB/c and C57BL/6 mice were inoculated intratracheally with 10(5) CAR bacillus organisms. CAR bacillus-specific serum immunoglobulins (immunoglobulin M [IgM], IgG1, IgG2a, IgG2b, IgG3, and IgA) and local pulmonary cytokines (tumor necrosis factor alpha [TNF-alpha], gamma interferon [IFN-gamma], and interleukin-4 [IL-4]) were evaluated by enzyme-linked immunosorbent assay every 7 days for 49 days. BALB/c mice developed CAR bacillus-induced lesions early in the course of disease that became more severe with time. Correlating with increasing disease severity, BALB/c mice had elevations in all antibody isotypes tested, and elevations in pulmonary TNF-alpha, IFN-gamma, and IL-4. C57BL/6 mice developed mild lesions with mild increases in serum IgM, IgG1, IgG2b, and IgG3 levels and minimally detectable IgG2a and IgA. Cytokine perturbations were not detected in C57BL/6 mice. The persistence of infection in BALB/c mice with vigorous serum antibody responses and increased IFN-gamma and IL-4 responses suggests that humoral immunity and T-cell responses are ineffective at preventing CAR bacillus disease. Furthermore, the lackluster antibody responses and undetectable cytokine responses in C57BL/6 mice suggest that humoral immunity and T-cell responses are not critical in resistance to CAR bacillus-induced disease.     

Naturally acquired human antibodies which recognize the first epidermal growth factor-like module in the Plasmodium falciparum merozoite surface protein 1 do not inhibit parasite growth in vitro.

Merozoite surface protein 1, one of the major surface proteins of the invasive blood stage of the malaria parasite, is a prime candidate for the development of a vaccine against the human disease. Previously, monoclonal antibodies which both inhibited the growth of Plasmodium falciparum in vitro and bound to the first of two epidermal growth factor-like modules located near the carboxy terminus of the protein had been identified. In this study, we have used affinity chromatography on a recombinant fusion protein corresponding to the first epidermal growth factor-like module in P. falciparum merozoite surface protein 1 to prepare antibody induced by natural infection. The antibody was purified from the total immunoglobulin G fraction of adult West African donors, shown to passively confer immunity against falciparum malaria. Such affinity-purified antibodies were shown to recognize the native protein by a number of separate criteria and to block the binding of an inhibitory monoclonal antibody, but they failed to inhibit parasite invasion in an in vitro growth assay. These results indicate that antibody alone is not sufficient to interfere with erythrocyte invasion.     

The effects of UV-B irradiation on the corneal endothelium

Rabbit eyes, in vivo and in vitro, were exposed to UV-B irradiation at 300 nm, from a mercury arc lamp with an 11 nm bandpass filter. Radiant exposure ranged from 0.1 J/cm2 to 0.5 J/cm2. In vivo, swelling of the cornea resulted over a 12 to 40 hr period, the extent and duration being directly related to exposure. Recovery of normal thickness was complete within four days. Corneas removed at 18 hr after exposure recovered normal thickness during a five hour perfusion period, except for those most heavily exposed. When removed at 42 hr post exposure all corneas thinned to almost normal thickness. SEM showed the endothelial cells of exposed eyes to have either exaggerated villi on the surface and a disorganized mosaic or, after higher exposures, to be devoid of villi and have loose, flap like cell borders and large "blebs." After exposure of isolated corneas mounted for perfusion, swelling again ensued and similar changes were observed in the appearance of the cells, except that "blebs" were not found. No significant changes were observed in the metabolic components ATP, ascorbate and glutathione, nor was there any indication of lipid peroxidation. At higher in vivo exposures, the aqueous humor did show a decrease in ascorbate concentration and an increase in protein content, which probably result from a breakdown of the blood-aqueous barrier. UV-B irradiation may cause or promote changes in the endothelium associated with aging, but the one time radiant exposures of the magnitude used in this study, appear to have no severe or permanently toxic effects.     

Machine Learning Predicts the Fall Risk of Total Hip Arthroplasty Patients Based on Wearable Sensor Instrumented Performance Tests

BackgroundThe prevalence of falls affects the wellbeing of aging adults and places an economic burden on the healthcare system. Integration of wearable sensors into existing fall risk assessment tools enables objective data collection that describes the functional ability of patients. In this study, supervised machine learning was applied to sensor-derived metrics to predict the fall risk of patients following total hip arthroplasty.MethodsAt preoperative, 2-week, and 6-week postoperative appointments, patients (n = 72) were instrumented with sensors while they performed the timed-up-and-go walking test. Preoperative and 2-week postoperative data were used to form the feature sets and 6-week total times were used as labels. Support vector machine and linear discriminant analysis classifier models were developed and tested on various combinations of feature sets and feature reduction schemes. Using a 10-fold leave-some-subjects-out testing scheme, the accuracy, sensitivity, specificity, and area under the receiver-operator curve (AUC) were evaluated for all models.ResultsA high performance model (accuracy = 0.87, sensitivity = 0.97, specificity = 0.46, AUC = 0.82) was obtained with a support vector machine classifier using sensor-derived metrics from only the preoperative appointment. An overall improved performance (accuracy = 0.90, sensitivity = 0.93, specificity = 0.59, AUC = 0.88) was achieved with a linear discriminant analysis classifier when 2-week postoperative data were added to the preoperative data.ConclusionThe high accuracy of the fall risk prediction models is valuable for patients, clinicians, and the healthcare system. High-risk patients can implement preventative measures and low-risk patients can be directed to enhanced recovery care programs.     

Clinical prediction models to predict the risk of multiple binary outcomes: a comparison of approaches

Clinical prediction models (CPMs) can predict clinically relevant outcomes or events. Typically, prognostic CPMs are derived to predict the risk of a single future outcome. However, there are many medical applications where two or more outcomes are of interest, meaning this should be more widely reflected in CPMs so they can accurately estimate the joint risk of multiple outcomes simultaneously. A potentially naïve approach to multi‐outcome risk prediction is to derive a CPM for each outcome separately, then multiply the predicted risks. This approach is only valid if the outcomes are conditionally independent given the covariates, and it fails to exploit the potential relationships between the outcomes. This paper outlines several approaches that could be used to develop CPMs for multiple binary outcomes. We consider four methods, ranging in complexity and conditional independence assumptions: namely, probabilistic classifier chain, multinomial logistic regression, multivariate logistic regression, and a Bayesian probit model. These are compared with methods that rely on conditional independence: separate univariate CPMs and stacked regression. Employing a simulation study and real‐world example, we illustrate that CPMs for joint risk prediction of multiple outcomes should only be derived using methods that model the residual correlation between outcomes. In such a situation, our results suggest that probabilistic classification chains, multinomial logistic regression or the Bayesian probit model are all appropriate choices. We call into question the development of CPMs for each outcome in isolation when multiple correlated or structurally related outcomes are of interest and recommend more multivariate approaches to risk prediction.     

Preliminary observations on the application of the multiple inocula (replicator) method for carbon substrate utilization studies of Alcaligenes faecalis.

The use of the replicator technique in evaluating carbon source utilization by 55 cultures of Alcaligenes faecalis was examined. Six of the 20 substrates tested were utilized by the bacterial cultures. In this study, the reproducibility of the technique was 100%.     

Expanding allelic and phenotypic spectrum of ZC4H2-related disorder: A novel hypomorphic variant and high prevalence of tethered cord

ZC4H2 (MIM# 300897) is a nuclear factor involved in various cellular processes including proliferation and differentiation of neural stem cells, ventral spinal patterning and osteogenic and myogenic processes. Pathogenic variants in ZC4H2 have been associated with Wieacker-Wolff syndrome (MIM# 314580), an X-linked neurodevelopmental disorder characterized by arthrogryposis, development delay, hypotonia, feeding difficulties, poor growth, skeletal abnormalities, and dysmorphic features. Zebrafish zc4h2 null mutants recapitulated the human phenotype, showed complete loss of vsx2 expression in brain, and exhibited abnormal swimming and balance problems. Here we report 7 new patients (four males and three females) with ZC4H2-related disorder from six unrelated families. Four of the 6 ZC4H2 variants are novel: three missense variants, designated as c.142T>A (p.Tyr48Asn), c.558G>A (p.Met186Ile) and c.602C>T (p.Pro201Leu), and a nonsense variant, c.618C>A (p.Cys206*). Two variants were previously reported : a nonsense variant c.199C>T (p.Arg67*) and a splice site variant (c.225+5G>A). Five patients were on the severe spectrum of clinical findings, two of whom had early death. The male patient harboring the p.Met186Ile variant and the female patient that carries the p.Pro201Leu variant have a relatively mild phenotype. Of note, 4/7 patients had a tethered cord that required a surgical repair. We also demonstrate and discuss previously under-recognized phenotypic features including sleep apnea, arrhythmia, hypoglycemia, and unexpected early death. To study the effect of the missense variants, we performed microinjection of human ZC4H2 wild-type or variant mRNAs into zc4h2 null mutant zebrafish embryos. The p.Met186Ile mRNA variant was able to partially rescue vsx2 expression while p.Tyr48Asn and p.Pro201Leu mRNA variants were not. However, swimming and balance problems could not be rescued by any of these variants. These results suggest that the p.Met186Ile is a hypomorphic allele. Our work expands the genotypes and phenotypes associated with ZC4H2-related disorder and demonstrates that the zebrafish system is a reliable method to determine the pathogenicity of ZC4H2 variants.     

An evaluation of three methods for determining colloid osmotic pressure

Plasma colloid osmotic pressure (COP) is an important determinant in edema formation. Three methods for assessing the COP were evaluated. Direct measurement of COP using the 4420 Wescor Colloid Osmometer was compared to the estimation of COP from both serum total protein and total serum solids (TSS) determinations. Blood samples from twenty adult patients (mean age = 64 years) undergoing cardiopulmonary bypass surgery were collected for COP assessment. Sample collection was performed prior to heparinization/hemodilution, during hypothermic bypass and at the conclusion of bypass following protamine administration. The results obtained from each method were analyzed by a two-way analysis of variance. The Bonferroni technique was used for comparison of sample means when the difference was significant (p less than 0.05). Correlations were reported by linear regression analysis. A statistically significant difference (p less than 0.01) was found between the three methods. A regression equation for the estimation of COP from total serum solids is offered: COP = (3.02 * TSS) + 0.65. Prospective clinical testing between the direct COP measurement and the estimation of COP from TSS using the equation (n = 38) revealed a significant correlation (R2 = .932) and no significant difference between the two (p greater than 0.05).     

Comparison of gaseous microemboli counts in arterial, simultaneous and venous heat exchange with a hollow fiber membrane oxygenator

Potential sources of gaseous microemboli during cardiopulmonary bypass are varied. However, it is known that membrane oxygenators generate fewer gaseous microemboli than bubble oxygenators and that bubblers cannot utilize arterial heat exchange without generating significant gaseous microemboli during rewarming. A membrane oxygenator utilizing simultaneous gas and heat exchange raises the concern that concurrent gas and heat exchange would result in a higher production of gaseous microemboli compared to conventional venous heat exchange devices. This in vitro study compared venous, simultaneous, arterial and control (venous) heat exchanger gaseous microemboli counts during rewarming. No significant difference was found between the four heat exchangers when comparing inlet and outlet gaseous microemboli counts. This in vitro study suggests that there is no difference in gaseous microemboli generation when varying the position of the heat exchanger in the extracorporeal circuit incorporating a microporous membrane oxygenator.