A recombinant fragment of von Willebrand factor reduces fibrin-rich microthrombi formation in mice with endotoxemia

INTRODUCTION

Disseminated fibrin deposition in the microvasculature such as in disseminated intravascular coagulation (DIC) arises from uninhibited activated coagulation secondary to sustained systemic inflammation. Currently there is no treatment for DIC. Treating the underlying trigger and supportive care are the current recommendations to manage DIC. This study aims at using recombinant von Willebrand factor (VWF) A2 domain polypeptide to inhibit VWF-mediated platelet adhesion to fibrin and prevent DIC.

MATERIALS AND METHODS

We use flow chamber assay to test the capacity of purified A2 protein to inhibit platelet adhesion to immobilized fibrin(ogen) and platelet-fibrin clot formation. We use a murine model of lipopolysaccharide-induced DIC to examine the effect of A2 protein on DIC.

RESULTS

The A2 protein blocked flow-dependent platelet adhesion to fibrin, delayed fibrin polymerization, and inhibited platelet-fibrin clot formation in vitro. The infusion of the purified A2 protein to the endotoxin-treated mice prevented fibrin-rich microthrombi formation in brain, lung, kidney, and liver. It also attenuated levels of inflammatory mediators, and markedly reduced mortality rates at 96hours.

CONCLUSIONS

The A2 protein inhibited platelet interaction with fibrin(ogen). Furthermore, A2 prevented disseminated fibrin-rich microthrombi and decrease mortality in a lipopolysaccharide-induced DIC murine model. A2 could provide a novel therapeutic approach in critically ill patients with uninhibited activated coagulation and disseminated fibrin deposition such as DIC.

Evaluation of the International Society on Thrombosis and Haemostasis and institutional diagnostic criteria of disseminated intravascular coagulation in pediatric patients

Globally, adult intensive care units routinely use the International Society on Thrombosis and Haemostasis (ISTH) scoring system for identifying overt disseminated intravascular coagulation (DIC). However, in our pediatric intensive care unit, a modified diagnostic criterion (Texas Children's Hospital [TCH] criteria) that requires serial monitoring of the coagulation variables is employed. A retrospective analysis of 2,136 DIC panels from 130 patients who had at least 4 DIC panels during 1 admission to a pediatric intensive care unit was done to compare the diagnostic utility of the TCH criteria with the ISTH scoring method in children. Both scoring systems were evaluated against the gold standard diagnostic method of autopsy confirmation of DIC in the subset of children who died. Receiver operating characteristic analysis indicates that TCH diagnostic criteria are comparable to the ISTH scoring method (area under the curve of 0.878 for TCH and 0.950 for ISTH). On the contrary, TCH diagnostic criteria perform better, with a sensitivity significantly higher than the ISTH scoring method when tested against the gold standard (P < .05). Fibrinogen is not a significant predictor of overt DIC in both models. Sequential testing of coagulation parameters is recommended for improved sensitivity when applying ISTH criteria to pediatric populations.

Plasma exchange therapy for thrombotic microangiopathies

Thrombotic microangiopathies (TMAs) are syndromes associated with thrombocytopenia and multiple organ failure. Plasma exchange is a proven therapy for primary TMA such as thrombotic thrombocytopenic purpura (TTP). There is growing evidence that plasma exchange therapy might also facilitate resolution of organ dysfunction and improve outcomes for secondary TMAs such as disseminated intravascular coagulation (DIC) and systemic inflammation-induced TTP. In this review, we survey the current available evidence and practice of plasma exchange therapy for TMAs.

Transmural strains in the ovine left ventricular lateral wall during diastolic filling

Rapid early diastolic left ventricular (LV) filling requires a highly compliant chamber immediately after systole, allowing inflow at low driving pressures. The transmural LV deformations associated with such filling are not completely understood. We sought to characterize regional transmural LV strains during diastole, with focus on early filling, in ovine hearts at 1 week and 8 weeks after myocardial marker implantation. In seven normal sheep hearts, 13 radiopaque markers were inserted to silhouette the LV chamber and a transmural beadset was implanted into the lateral equatorial LV wall to measure transmural strains. Four-dimensional marker dynamics were obtained 1 week and 8 weeks thereafter with biplane videofluoroscopy in closed-chest, anesthetized animals. LV transmural strains in both cardiac and fiber-sheet coordinates were studied from filling onset to the end of early filling (EOEF, 100 ms after filling onset) and at end diastole. At the 8 week study, subepicardial circumferential strain (ECC) had reached its final value already at EOEF, while longitudinal and radial strains were nearly zero at this time. Subepicardial ECC and fiber relengthening (Eff) at EOEF were reduced to 1 compared with 8 weeks after surgery (ECC:0.02+/-0.01 to 0.08+/-0.02 and Eff:0.00+/-0.01 to 0.03+/-0.01, respectively, both P<0.05). Subepicardial ECC during early LV filling was associated primarily with fiber-normal and sheet-normal shears at the 1 week study, but to all three fiber-sheet shears and fiber relengthening at the 8 week study. These changes in LV subepicardial mechanics provide a possible mechanistic basis for regional myocardial lusitropic function, and may add to our understanding of LV myocardial diastolic dysfunction.

Sheep histocompatibility antigens: a population level comparison between lymphocyte antigens previously defined in France, England and Scotland, and sheep red cell groups

A comparison test was performed to look for correlations between the three nomenclature systems for sheep histocompatibility antigens which have been previously described in France, England and Scotland. 187 French sheep from a wide variety of breeds were typed for lymphocyte antigens with antisera which detect the OLA, P and ED series of antigens; they were also tested against 387 uncharacterized French antisera. Six clusters of sera were found which showed correspondence between antigens of at least two of the three nomenclatures; five of these clusters gave high r values of 0.78-0.94. New antisera from French sheep were found which contributed to the above clusters but few additional clusters were noted. No correlation was found between any of the lymphocyte groups of antisera tested and the sheep red cell antigens which were also tested.

Absence of evidence for linkage between Booroola gene and genetic markers at 11 sheep blood polymorphic loci

Genetic linkage between the Booroola locus (Fec) and 11 sheep blood polymorphic loci (i.e. Tf, Hb, CA, OLA, and A, B, C, D, M, R, F41 red cell blood groups) was investigated in six large sire families (163 informative female offspring). The six sires tested were heterozygous for the Booroola allele (FecB) and for several genetic markers. No evidence in favour of linkage was found. Moreover, depending on the marker locus considered, linkage closer than or as close as the recombination frequency of 10-30% was excluded.

Sheep blood polymorphism and genetic divergence between French Rambouillet and Spanish Merino: role of genetic drift

Rambouillet sheep originating from Spanish Merino have been maintained in France as a small and closed flock since their importation. After 190 years of independent evolution, the flock has markedly differentiated from its Spanish parental population. The observed differences between them were characterized by the fixation in Rambouillet of the Mb and F30 alleles, which occurred in Spanish Merino with frequencies of 0.90 and 0.80 respectively (at two distinct blood group loci M and F30) and by the absence in Rambouillet of other alleles or phenogroups (at the Tf and the A, B, C blood group loci) which were observed in Spanish Merino with frequencies ranging from 0.10 to 0.28. On the basis of their phenotypic distributions at 11 blood polymorphic loci, the two populations differed significantly from each other (total chi 2 values = 352.62, 23 df, P less than 0.001). By comparing the observed magnitude of gene frequency differences between Rambouillet and Spanish Merino with the estimate of inbreeding coefficient for Rambouillet obtained from pedigrees, it appeared that the observed genetic differences could be attributed to the evolutionary change due to random drift in the small and closed flock of Rambouillet.

Evaluation of linkage between the R-O-i and C blood group systems in sheep

Linkage between the C and I blood group loci in sheep was demonstrated by lod score analysis of data from double backcross matings. The recombination frequency between the I locus and the gene coding for the Cb red cell antigen was estimated to be 0.09 with a standard error of 0.04.

Assessment of common hyperelastic constitutive equations for describing normal and osteoarthritic articular cartilage

With the aim of providing information for modelling joint and limb systems, widely available constitutive hyperelastic laws are evaluated in this paper for their ability to predict the mechanical responses of normal and osteoarthritic articular cartilage. Load—displacement data from mechanical indentation were obtained for normal and osteoarthritic cartilage at 0.1 s−1 and 0.025 s−1 and converted to the stress—stretch ratio. The data were then fitted to the ArrudA—Boyce, Mooney—Rivlin, neo-Hookean, Ogden, polynomial, and Yeoh hyperelastic laws in the MATLAB environment. Although each of the hyperelastic laws performed satisfactorily at the higher rate of loading, their ability to fit experimental data at the lower loading rate varied considerably. For the preferred models, coefficients were provided for stiff, soft, and average tissues to represent normal and degraded tissue at high and low loading rates. The present authors recommend the use of the Mooney—Rivlin or the Yeoh models for describing both normal and degraded articular cartilage, with the Mooney—Rivlin model providing the best compromise between accuracy and required computational power.

Retinopathy of prematurity in the United States

AIMS

To determine the incidence of retinopathy of prematurity (ROP) based upon a national database and to identify baseline characteristics, demographic information, comorbidities, and surgical interventions.

METHODS

The National Inpatient Sample, a representative sample of all US hospital discharges from 1997 to 2002, was queried for all newborn infants with and without ROP. Primary outcome variables included demographics, comorbidities, hospital length of stay (LOS), and hospital charges. Multivariate logistic regression was used to predict risk factors for ROP.

RESULTS

4.67 million live births were recorded during the study period. The total incidence of ROP was 0.12% overall and 7.35% for premature infants with LOS greater than 14 days. Newborns with ROP were more likely to be born at a teaching hospital and to have higher LOS and hospitalisation charges. The odds ratios for the development of ROP were greatest in infants weighing less than 1250 grams. The multivariate regression model revealed that only respiratory distress and intraventricular haemorrhage were predictive of the development of ROP and Hispanic infants were 33% more likely to develop ROP.

CONCLUSION

This study represents the largest cohort of newborns analysed for ROP. The multivariate analysis emphasised the role of birth weight in extended-stay infants, as well as Hispanic race, respiratory distress syndrome, and intraventricular haemorrhage.

Bench-to-bedside review: thrombocytopenia-associated multiple organ failure--a newly appreciated syndrome in the critically ill

New onset thrombocytopenia and multiple organ failure (TAMOF) presages poor outcome in critical illness. Patients who resolve thrombocytopenia by day 14 are more likely to survive than those who do not. Patients with TAMOF have a spectrum of microangiopathic disorders that includes thrombotic thrombocytopenic purpura (TTP), disseminated intravascular coagulation (DIC) and secondary thrombotic microanigiopathy (TMA). Activated protein C is effective in resolving fibrin-mediated thrombosis (DIC); however, daily plasma exchange is the therapy of choice for removing ADAMTS 13 inhibitors and replenishing ADAMTS 13 activity which in turn resolves platelet: von Willebrand Factor mediated thrombosis (TTP/secondary TMA).

Acquired ADAMTS-13 deficiency in pediatric patients with severe sepsis

We studied the state of ultra-large von Willebrand factor (ULVWF) proteolysis in 21 pediatric patients with severe sepsis and found that the overall group of patients had moderately reduced ADAMTS-13 activity, but 31% had severe enzymatic deficiency. The severe deficiency correlated with greater adhesion activity of von Willebrand factor, severity of thrombocytopenia and plasma levels of interleukin-6. It also correlated clinically with severity of illness and organ dysfunction. These results suggest that ULVWF proteolysis is insufficient in septic patients and severely deficient in a subgroup of patients. The deficiency may contribute to the development of thrombocytopenia and ischemic organ failure associated with sepsis.

Unexpected increased mortality after implementation of a commercially sold computerized physician order entry system

OBJECTIVE

In response to the landmark 1999 report by the Institute of Medicine and safety initiatives promoted by the Leapfrog Group, our institution implemented a commercially sold computerized physician order entry (CPOE) system in an effort to reduce medical errors and mortality. We sought to test the hypothesis that CPOE implementation results in reduced mortality among children who are transported for specialized care.

METHODS

Demographic, clinical, and mortality data were collected of all children who were admitted via interfacility transport to our regional, academic, tertiary-care level children's hospital during an 18-month period. A commercially sold CPOE program that operated within the framework of a general, medical-surgical clinical application platform was rapidly implemented hospital-wide over 6 days during this period. Retrospective analyses of pre-CPOE and post-CPOE implementation time periods (13 months before and 5 months after CPOE implementation) were subsequently performed.

RESULTS

Among 1942 children who were referred and admitted for specialized care during the study period, 75 died, accounting for an overall mortality rate of 3.86%. Univariate analysis revealed that mortality rate significantly increased from 2.80% (39 of 1394) before CPOE implementation to 6.57% (36 of 548) after CPOE implementation. Multivariate analysis revealed that CPOE remained independently associated with increased odds of mortality (odds ratio: 3.28; 95% confidence interval: 1.94-5.55) after adjustment for other mortality covariables.

CONCLUSIONS

We have observed an unexpected increase in mortality coincident with CPOE implementation. Although CPOE technology holds great promise as a tool to reduce human error during health care delivery, our unanticipated finding suggests that when implementing CPOE systems, institutions should continue to evaluate mortality effects, in addition to medication error rates, for children who are dependent on time-sensitive therapies.

Walking speed in children and young adults with neuromuscular disease: comparison between two assessment methods

Self-selected walking speed is being increasingly used as a primary outcome measure in the management of neuromuscular disease. It would be useful if the speed recorded in the gait laboratory represented the child's walking speed in the community. This study investigated the difference in self-selected walking speeds between a 10-meter walk, as measured during instrumented gait analysis, and a 10-minute walk. The authors found that self-selected walking speed during the 10-minute walk was slower than the self-selected walking speed recorded during the 10-meter walk. The former may be more representative of walking speed in the community setting. Walking speed measured during walks of 10 minutes or more should become an integral part of gait laboratory evaluation.

Arsenic contamination of groundwater and drinking water in Vietnam: a human health threat

This is the first publication on arsenic contamination of the Red River alluvial tract in the city of Hanoi and in the surrounding rural districts. Due to naturally occurring organic matter in the sediments, the groundwaters are anoxic and rich in iron. With an average arsenic concentration of 159 micrograms/L, the contamination levels varied from 1 to 3050 micrograms/L in rural groundwater samples from private small-scale tubewells. In a highly affected rural area, the groundwater used directly as drinking water had an average concentration of 430 micrograms/L. Analysis of raw groundwater pumped from the lower aquifer for the Hanoi water supply yielded arsenic levels of 240-320 micrograms/L in three of eight treatment plants and 37-82 micrograms/L in another five plants. Aeration and sand filtration that are applied in the treatment plants for iron removal lowered the arsenic concentrations to levels of 25-91 micrograms/L, but 50% remained above the Vietnamese Standard of 50 micrograms/L. Extracts of sediment samples from five bore cores showed a correlation of arsenic and iron contents (r2 = 0.700, n = 64). The arsenic in the sediments may be associated with iron oxyhydroxides and released to the groundwater by reductive dissolution of iron. Oxidation of sulfide phases could also release arsenic to the groundwater, but sulfur concentrations in sediments were below 1 mg/g. The high arsenic concentrations found in the tubewells (48% above 50 micrograms/L and 20% above 150 micrograms/L) indicate that several million people consuming untreated groundwater might be at a considerable risk of chronic arsenic poisoning.

Blood polymorphism in west African breeds of sheep

This paper reports the blood groups and blood protein distribution in West African sheep breeds. About 100 animals of the Djallonke, Fulani and Touabire breeds were sampled for blood polymorphism analysis. Their blood groups were typed by haemolytic and agglutination reactions, and their blood proteins by starch gel electrophoresis. Almost all the loci analysed showed variability in the three breeds, with the Touabire and Fulani being closer to each other than to the Djallonke.

Note on transferrin, hemoglobin types, and packed cell volume in Senegalese trypanotolerant Djallonke sheep

In this study we examined transferrin (Tf) and hemoglobin (Hb) types and frequencies and their relationship with Packed Cell Volume (PCV), which is considered as a selection criterion for the trypanotolerance trait. Blood samples were collected from 96 sheep and were typed for Tf and Hb. The frequencies of the alleles TfA, TfB, TfC and TfD were respectively 0.276, 0.005, 0.109, and 0.609. At the locus Hb, all animals were monomorphic B. The lowest PCV value was observed in animals homozygous for TfC, while the highest value was found in heterozygous (CD) animals; however, the difference was not significant.

Noise levels and hearing ability of female workers in a textile factory in Vietnam

Noise and hearing ability profiles were determined in a textile factory in Vietnam. Noise mapping done in the weaving section showed that the noise levels exceeded the Vietnamese standard of 90 dBA by as much as 9 dBA in some areas. Audiometric tests performed on 69 female workers from the weaving section revealed that workers with more than 10 years of noise exposure had the worst hearing threshold levels at 1,000 and 4,000 Hz. Similar findings were observed for workers greater than 35 years old. The 4,000 Hz notch, suggestive of exposure to intense noise, was noted in the audiograms of 26 subjects.

Short courses of ofloxacin for the treatment of enteric fever

Typhoid fever continues to be a major public health problem in tropical countries, exacerbated in recent years by the spread of multi-drug resistant strains of Salmonella typhi. Short treatment courses of fluoroquinolones are effective, and have the advantage of reduced cost and increased compliance, but the optimal length of treatment is unknown. In an open, randomized comparison, 107 adults with uncomplicated enteric fever (95 of whom had positive blood cultures for S. typhi and 5 for S. paratyphi) were treated with oral ofloxacin, 15 mg/kg/d for 2 d or 10 mg/kg/d for 3 d. Mean fever clearance times were the same in the 2 treatment groups (97 h). There were 7 treatment failures, one in the 2 d group and 6 in the 3 d group (P = 0.07). Three of the 5 patients infected with nalidixic acid resistant strains of S. typhi had treatment failures, compared with 4 of 90 with nalidixic acid sensitive isolates (P < 0.0001; relative risk 13.5, 95% confidence interval 4.1-43%). Treatment with ofloxacin for 2 or 3 d is equally effective in adults with uncomplicated enteric fever caused by nalidixic acid sensitive strains of S. typhi. The epidemiology and management of nalidixic acid resistent typhoid needs further investigation.

Occupational exposure and chronic respiratory symptoms--a population based study in Vietnam

In order to investigate the relationship between occupational exposure to dust/chemicals (toxic gases/fumes) and chronic respiratory symptoms in Vietnam, the questionnaire standardized by the American Thoracic Society was applied to 368 subjects living in Ha Thai district of Vietnam. According to the results of multiple logistic regression analyses, the odds ratios of chronic respiratory symptoms by occupational exposure are over unity, except for the relationship between chronic cough and occupational exposure to chemicals. Especially for chronic breathlessness, significantly higher odds ratios are observed among people with a history of occupational exposure to dust or chemicals: 2.925 (95% CI: 1.130-7.574) for dust, and 3.721 (95% CI: 1.412-9.803) for chemicals. As for the interaction between occupational exposure to dust and cigarette smoking, it is considered that occupational exposure leads to an increase in chronic respiratory symptoms independent of the effects of cigarette smoking.