Paralysis of phagocyte migration due to an artificial blood substitute

We investigated the effect of a candidate artificial blood substitute, Fluosol-DA (FDA), on human neutrophil function in a serum-free medium. In a 50% (vol/vol) mixture with polymorphonuclear cells (PMN), FDA had no effect on PMN viability, phagocytosis, superoxide anion generation, degranulation, or bactericidal activity. In striking contrast, the random migration and chemotaxis of PMN to both f-Met-Leu-Phe (fMLP) and activated serum were inhibited by 98% +/- 2%, 95% +/- 2%, and 88% +/- 6%, respectively. Inhibition of chemotaxis by FDA required no preincubation, was dose-dependent (50% inhibition [ID50] with a 14% vol/vol mixture with FDA), and was fully reversible by washing PMN free of FDA after one hour but not after 18 hours of incubation (32% +/- 11% inhibition of chemotaxis). FDA itself was not chemotactic and did not impair either the chemotactic activity or binding of fMLP to PMN. FDA also inhibited PMN adhesion (ID50, 9 +/- 1 vol/vol%). The inhibitory component of FDA was found to be its detergent additive, Pluronic F-68, which inhibited random migration, chemotaxis, and adhesion with ID50s of 1.4, 2.4, and 2.9 mg/mL, respectively (equivalent to FDA concentrations of 5, 9, and 11 vol/vol%, respectively). All the other components of FDA were noninhibitory. Plasma samples from humans injected with 8 mL/kg FDA and plasma samples from rabbits injected with 16 mL/kg FDA or an equivalent concentration of Pluronic F-68, when mixed with autologous PMN, also severely inhibited PMN chemotaxis. We conclude that exposure of PMN to clinically relevant concentrations of FDA inhibits PMN migration, presumably due to inhibition of adhesion. The inhibitory effect is entirely due to the detergent, Pluronic F-68. Artificial blood substitutes containing Pluronic F-68 may compromise the ability of PMN to prevent or effectively control microbial infections.     

Pediatric mortality due to nosocomial infection: a critical approach.

Nosocomial infection is a frequent event with potentially lethal consequences. We reviewed the literature on the predictive factors for mortality related to nosocomial infection in pediatric medicine. Electronic searches in English, Spanish and Portuguese of the PubMed/MEDLINE, LILACS and Cochrane Collaboration Databases was performed, focusing on studies that had been published from 1996 to 2006. The key words were: nosocomial infection and mortality and pediatrics/neonate/ newborn/child/infant/adolescent. The risk factors found to be associated with mortality were: nosocomial infection itself, leukemia, lymphopenia, neutropenia, corticosteroid therapy, multiple organ failure, previous antimicrobial therapy, catheter use duration, candidemia, cancer, bacteremia, age over 60, invasive procedures, mechanical ventilation, transport out of the pediatric intensive care unit, methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, and Burkholderia cepacia infections, acute physiology and chronic health evaluation (APACHE) II scores over 15. Among these factors, the only one that can be minimized is inadequate antimicrobial treatment, which has proven to be an important contributor to hospital mortality in critically-ill patients. There is room for further prognosis research on this matter to determine local differences. Such research requires appropriate epidemiological design and statistical analysis so that pediatric death due to nosocomial infection can be reduced and health care quality improved in pediatric hospitals.     

Cross-sex transmission of infection and increased mortality due to measles

In an urban and a rural area of Guinea-Bissau, the incidence of and mortality due to measles were followed over four years. Significantly higher case-fatality ratios among secondary cases occurred when infection was transmitted across sexes than within the same sex. The case-fatality ratio was highest for girls infected by boys and lowest for girls infected by girls. Published reports of cases of fatal measles indicate a similar tendency. Apparently, no general background factor or difference in social interaction between children can explain this variation in severity of infection. It is therefore hypothesized that cross-sex transmission of measles virus produces infections of greater severity. These observations may suggest that measles virus incorporates host-specific cellular characteristics that interfere with the immune responses of persons infected by a member of the opposite sex.     

Increased renal vascular sensitivity to angiotensin II in hypertension is due to decreased response to prostaglandins

OBJECTIVES: An enhanced sensitivity to angiotensin II in the renal circulation has been demonstrated in the pre-hypertensive phase both in the spontaneously hypertensive rat and in man. To further characterize this abnormality and the role of prostanoids, renal haemodynamics in normotensive young men with a positive (PFH) or a negative (NFH) family history of hypertension were studied. METHODS: Renal vascular reactivity was assessed during infusion of angiotensin II with and without inhibition of prostaglandin synthesis. Normotensive men with PFH (n = 13) and with NFH (n = 10) with a mean age of 38 years were given on two different occasions: (i). angiotensin II infusion i.v. (0.1, 0.5 and 1.0 ng/kg per min) and (ii). angiotensin II infusion after inhibition of prostaglandin synthesis with indomethacin (150 mg daily three consecutive days). Glomerular filtration rate (GFR) and renal plasma flow were measured with renal clearances of chromium edetic acid and para-aminohippuric acid. RESULTS: Before angiotensin II challenge, the groups did not differ with respect to blood pressure, body mass index, plasma renin activity, GFR, renal blood flow (RBF) or urinary sodium excretion. There was no significant difference in systolic or diastolic blood pressure response to angiotensin II between the two groups. In PFH, the lowest angiotensin II dose caused a significant decrease in RBF and increase in renal vascular resistance (RVR) from baseline (P < 0.01 for both). In NFH, only the highest angiotensin II dose produced a significant decrease in RBF and increase in RVR (P < 0.01 for both). During inhibition of prostaglandin synthesis, all three angiotensin II doses caused a significant decrease in RBF (P < 0.02) and increase in RVR (P < 0.02) also in NFH. The renal haemodynamic difference between PFH and NFH was thus eliminated. CONCLUSIONS: These findings indicate that young human subjects with a positive family history of hypertension have a defective vasodilator prostaglandin system, which is responsible for increased renal vascular sensitivity to angiotensin II. Enhanced renal vasoconstriction may be an early event leading to the generation of primary hypertension.     

Simplified micropore filter assay of neutrophil migration using whole blood

A new method of micropore filter assay of neutrophil migration requiring only 0.1 ml of whole blood is described and compared with the standard separated polymorphonuclear neutrophil micropore filter assay. Whole blood was added to the upper compartment of a modified Boyden chemotactic chamber, and the neutrophils were allowed to migrate into a cellulose nitrate micropore filter. Acetic acid was used to remove erythrocytes and hemoglobin from the filter. Neutrophil chemotaxis was performed with cells from 19 neonates and 34 adults. The mean neonatal PMN migration was 40% of the adult value (48.1 +/- 12.6 vs 96.8 +/- 16.8 micron) with the whole blood assay and 39% of the adult value (44.7 +/- 10.1 vs 72.9 +/- 22.2 micron) with the separated polymorphonuclear neutrophil assay. The whole blood micropore filter assay, a simple and reliable method of determining neutrophil migration, is especially useful in studying patients when there are difficulties in obtaining large blood samples, such as with neonates and young children.     

Altered neutrophil migration during bacterial infection associated with a serum modulator of cellular motility

The motility of polymorphonuclear leukocytes (PMNLs) from 25 patients with bacterial infection was assessed by using the migration-under-agarose assay. A spectrum of responses was observed. Random and directional motility stimulated by C5a or pressed in parallel. These responses contrasted with those of normal PMNLs preincubated with either FMLP or C5a; preincubation with one chemotaxin inhibited a subsequent response to the same stimulus but did not inhibit the response to the other. The parallel responses of patient PMNLs to C5a and FMLP suggest that the altered motility reflects a perturbation independent of a specific chemotactic receptor. Heat-inactivated serum from patients with bacterial infection, when preincubated with normal PMNLs, resulted in significant enhancement of both random and directional migration. The data indicate that bacterial infection is associated with appearance of a modulator of neutrophil motility.     

Increased blood levels of venetoclax due to intake of crushed venetoclax tablets

Annals of Hematology -     

Methemoglobinemia due to ingestion of N,N-dimethyl-p-toluidine, a component used in the fabrication of artificial fingernails

An acute cyanotic episode due to methemoglobinemia occurred in a 16-month old girl following the ingestion of N,N-dimethyl-p-toluidine, a commercially available component used in the production of artificial fingernails. The amount of the parent compound ingested was about 6 mg/kg of body weight. Administration of methylene blue was effective in the reversal of the methemoglobinemia. In vitro studies suggest that the activity of the compound was probably due to its biochemical transformation to the toxic metabolite p-methylphenylhydroxylamine. We expand the list of aromatic amino or nitro compounds and their derivatives capable of producing methemoglobinemia and call attention to the hazard of their ingestion.     

Increased blood proinsulin and decreased C-peptide levels in patients with pancreatic cancer

BACKGROUND/AIMS: Abnormal glucose tolerance during oral glucose tolerance test (OGTT) is frequently observed in patients with pancreatic cancer. The abnormality shown in previous studies, however, was characterized mainly by analyses based on immunoreactive insulin or C-peptide response during OGTT, despite their cross-reactivity with proinsulin. The mechanisms responsible for glucose intolerance in patients with pancreatic cancer remain controversial. METHODOLOGY: Both proinsulin and C-peptide responses during 75 g of OGTT were determined without influence of immunologic cross-reactivity in 32 patients with pancreatic cancer and 32 control subjects of similar age, sex, fasting blood glucose levels, and OGTT pattern. RESULTS: The pancreatic cancer patients had higher proinsulin and lower C-peptide levels than the control subjects both in the non-diabetic and diabetic groups. The ratio of the sum of five proinsulin values observed at 0, 30, 60, 120, and 180 min to that of the five C-peptide values (sigma proinsulin/sigma C-peptide ratio) was 6.1 +/- 3.2% in patients with pancreatic cancer and 2.5 +/- 1.0% in control subjects (p < 0.05), while it was not associated with the diabetic pattern in OGTT. The sigma proinsulin/sigma C-peptide ratio was not associated with tumor size, location or resectability but was associated with the number of islets left within or close to cancer stroma. The increased sigma proinsulin/sigma C-peptide ratio decreased after tumor removal. CONCLUSIONS: Patients with pancreatic cancer are characterized by increased proinsulin secretion and decreased C-peptide production during OGTT probably due to impaired proinsulin conversion. Although further studies are required in a large scale of patients, measurement of proinsulin and C-peptide levels during OGTT should serve as an early marker to identify high risk groups of the disease.     

Increased sensitivity to complement and a decreased red blood cell life span in mice mosaic for a nonfunctional Piga gene.

The gene PIGA encodes one of the protein subunits of the alpha1-6-N acetylglucosaminyltransferase complex, which catalyses an early step in the biosynthesis of glycosyl phosphatidylinositol (GPI) anchors. PIGA is somatically mutated in blood cells from patients with paroxysmal nocturnal hemoglobinuria (PNH), leading to deficiency of GPI-linked proteins on the cell surface. To investigate in detail how inactivating mutations of the PIGA gene affect hematopoiesis, we generated a mouse line, in which loxP-mediated excision of part of exon 2 occurs on the expression of Cre. After crossbreeding with EIIa-cre transgenic mice, recombination occurs early in embryonic life. Mice that are mosaics for the recombined Piga gene are viable and lack GPI-linked proteins on a proportion of circulating blood cells. This resembles the coexistence of normal cells and PNH cells in patients with an established PNH clone. PIGA(-) blood cells in mosaic mice have biologic features characteristic of those classically seen in patients with PNH, including an increased sensitivity toward complement mediated lysis and a decreased life span in circulation. However, during the 12-month follow-up, the PIGA(-) cell population did not increase, clearly showing that a Piga gene mutation is not sufficient to cause the human disease, PNH.     

White-blood-cell-containing allogeneic blood transfusion and postoperative infection or mortality: an updated meta-analysis

BACKGROUND: Additional randomized controlled trials (RCTs) comparing recipients of non-white-blood-cell-(WBC)-reduced and WBC-reduced allogeneic red blood cells (RBCs) have been reported since the undertaking of previous meta-analyses of the association of allogeneic blood transfusion (ABT) with postoperative infection and/or mortality. Because no further RCTs are underway, a final meta-analysis of all available RCTs was conducted. METHODS: RCTs reporting on the association of ABT with postoperative infection and/or short-term (up to 3-month post-transfusion), all-cause mortality were retrieved. Twelve RCTs reporting on infection and 11 RCTs reporting on mortality were eligible for meta-analysis. Summary odds ratios (ORs) of infection or mortality in recipients of WBC-containing ABT vs. WBC-reduced ABT were calculated across the studies. RESULTS: An association of ABT with postoperative infection was demonstrated across RCTs transfusing RBCs WBC-reduced after storage [summary OR = 2.25; 95% confidence interval (CI), 1.12-4.25] but not before storage (summary OR = 1.06; 95% CI, 0.91-1.24). An association of ABT with mortality was demonstrated across RCTs conducted in cardiac surgery (summary OR = 1.72, 95% CI, 1.05-2.81) and across RCTs transfusing buffy-coat-reduced RBCs vs. RBCs WBC-reduced before storage (summary OR = 1.60; 95% CI, 1.14-2.24), but not across RCTs transfusing non-buffy-coat-reduced RBCs vs. RBCs WBC-reduced before storage (summary OR = 1.01; 95% CI, 0.73-1.40). CONCLUSIONS: An association between ABT and postoperative infection or short-term mortality is not detected across all clinical settings and transfused RBC products. An association between ABT and mortality is detected in cardiac surgery, but the other associations found in subgroup analyses contradict current theories about mechanism(s) of the ABT effect.     

Increased severity of respiratory syncytial virus airway infection due to passive smoke exposure

Objective

Aim of this study was to analyze whether children with objectively measured second‐hand cigarette smoke (SHS) exposure suffer from a more severe course of disease when hospitalized with lower respiratory tract infection (LRTI) due to respiratory syncytial virus (RSV).

Methods

This prospective study was conducted at the Department of Pediatrics, Wilhelminen‐Hospital, Vienna, Austria in children aged below 1 year without a history of preceding lung disease and with acute symptoms of LRTI and a positive nasopharyngeal swab for RSV. On admission, urinary cotinine was measured as a marker of recent SHS and clinical severity of LRTI was assessed by oxygen saturation SpO₂ and the “admission clinical severity score” (CSSA). Parents/caregivers were asked to complete a customized questionnaire assessing risks for SHS and demographic characteristics.

Results

After inclusion of 217 patients, data of 185 patients with a mean (SD) age of 106 days (80) were analyzed. Twenty‐five patients (13.5%) were “cotinine‐positive” (COT+) defined as a urinary cotinine level of ≥7 μg/L. SpO₂ on admission was significantly lower in children recently exposed to SHS defined objectively by COT+ (94.8% ±2.0) in urine on admission compared to children not recently exposed (COT−) (96.8% ±3.0; P < 0.01). Disease severity, assessed via mean clinical severity score on admission (CSSA) for COT+ and COT− was 2.56 and 1.71, respectively (P = 0.03).

Conclusions

Recent exposure to SHS was associated with lower O₂ saturation and higher clinical severity score, measured by urine cotinine levels in children hospitalized for RSV infection under 1 year of age.

     

CD157 is an important mediator of neutrophil adhesion and migration

CD157, a glycosylphosphatidylinositol (GPI)-anchored protein encoded by a member of the CD38 NADase/ADP-ribosyl cyclase gene family, is expressed on the surface of most human circulating neutrophils. This work demonstrates that CD157 is a receptor that induces reorganization of the cytoskeleton and significant changes in cell shape, and that signals mediated by CD157 act through modulation of cytosolic Ca(2+) concentration. These signals are independent of the products of CD157's enzymatic activities (ie, cyclic adenosine diphosphate [ADP]-ribose and ADP-ribose). Indeed, the enzymatic activities of CD157 in circulating neutrophils as well as in dimethyl sulfoxide (DMSO)-differentiated (CD157(+)/CD38(-)) HL-60 cells, are hardly detectable. This work also shows that the receptorial activity relies on cross-talk between CD157 and beta(2) integrin. CD157 localizes in GM1-enriched lipid rafts and, upon activation, it migrates to the uropod, a structure specialized in motility and adhesive functions. Indeed, CD157 is involved in adhesion to extracellular matrix proteins and in chemotaxis induced in vitro by formyl-methionyl-leucyl-phenylalanine (fMLP). These findings were consistent with the results obtained in neutrophils from patients with paroxysmal nocturnal hemoglobinuria (PNH), in which CD157 is deficient. These neutrophils showed constant defects in adhesion and migration. Our data attribute specific and crucial roles to CD157 in the regulation of innate immunity during inflammation.     

A prospective cohort study on hospital mortality due to Clostridium difficile infection

Purpose

Although an increase in burden of disease has frequently been reported for Clostridium difficile infection (CDI), specific data on the effect of CDI on a patient??s risk of death or overall hospital mortality are scarce. Therefore, we performed a prospective cohort study to analyse the effect of CDI on the risk of pre-discharge all-cause death in all inpatients with CDI compared to all inpatients without CDI during 2009 in a single hospital.

Methods

Clostridium difficile infection was defined as by the European Society of Clinical Microbiology and Infectious Diseases. Data were collected from the medical charts of CDI patients and from the hospital discharge data of non-CDI and CDI patients. The effect measures of CDI used to compute the risk of pre-discharge all-cause death were risk ratio, attributable risk, mortality fraction (%) and population attributable risk percentage. Co-morbidity was categorized using the Charlson co-morbidity score in which a value of ??2 was defined as low co-morbidity and that of >2 as moderate/severe co-morbidity. A stratified analysis and a Poisson regression model were applied to adjust for the effects of the risk factors sex, age and severity of co-morbidity.

Results

A total of 185 hospitalized patients with CDI were compared to 38,644 other hospitalized patients without CDI admitted between 1 January 2009 and 31 December 2009. The mean age of the CDI and non-CDI patients was 74.3 (range 72.3?C76.4) and 51.9 (range 51.6?C52.1)?years, respectively. Of the 185 CDI, 136 (73.5?%) and 49 (26.5?%) were categorized with low and high co-morbidity, respectively, versus 32,107 (83.4?%) and 6,352 (16.5?%), respectively, in non-CDI patients. Overall, 24 of the 185 CDI patients (13?%) versus 1,021 of the 38,459 non-CDI patients (2.7?%) died during their hospital stay, resulting in a relative risk of pre-discharge death of 4.89 [95?% confidence interval (CI) 3.35?C7.13] for CDI patients, a CDI attributable risk of death of 10.3 per 100 patients and a CDI attributable fraction of 79.5 % (95?% CI 70.1?C86 %). After adjustment for age, sex and co-morbidity the relative risk of pre-discharge death was 2.74 (95?% CI 1.82?C4.10; p?<?0.0001) for patients with CDI, and the proportion of hospital deaths due to CDI was 1.72 (95?% CI 1.22?C2.05).

Conclusion

The results of this study lead to the conclusion that hospitalized patients with CDI are??independent of age, sex and co-morbidity severity??2.74-fold more likely to die during their hospital stay than all other hospitalized patients. The eradication of CDI in the hospital could have prevented 1.72?% of in-hospital deaths in our study population during the 1 year of the study.