Mutant torsinA interacts with tyrosine hydroxylase in cultured cells.

A specific mutation (DeltaE302/303) in the torsinA gene underlies most cases of dominantly inherited early-onset torsion dystonia. This mutation causes the protein to aggregate and form intracellular inclusion bodies in cultured cells and animal models. Co-expression of the wildtype and mutant proteins resulted in the redistribution of the wildtype protein from the endoplasmic reticulum to inclusion bodies in cultured HEK293 cells, and this was associated with increased interaction between the two proteins. Expression of DeltaE302/303 but not wildtype torsinA in primary postnatal midbrain neurons resulted in the formation of intracellular inclusion bodies, predominantly in dopaminergic neurons. Tyrosine hydroxylase was sequestered in these inclusions and this process was mediated by increased protein-protein interaction between mutant torsinA and tyrosine hydroxylase. Analysis in an inducible neuroblastoma cell culture model demonstrated altered tyrosine hydroxylase activity in the presence of the mutant but not wildtype torsinA protein. Our results suggest that the interaction of tyrosine hydroxylase and mutant torsinA may contribute to the phenotype and reported dopaminergic dysfunction in torsinA-mediated dystonia.

Sid4: A secreted vertebrate immunoglobulin protein with roles in zebrafish embryogenesis.

The small members of the immunoglobulin superfamily (IGSF) are a molecularly diverse group of proteins composed solely of immunoglobulin domains. They may be secreted or tethered to the cell mebrane via GPI linkages and are proposed to have important functions in vivo. However, very few small IGSFs have been functionally characterized. During an ongoing in situ hybridization analysis of expressed sequence tags in zebrafish we identified secreted immunoglobulin domain 4 (sid4), a gene encoding a soluble vertebrate protein composed solely of four immunoglobulin domains. Throughout development, sid4 is expressed in regions of the embryo undergoing active cell division and migration. Functional analysis using morpholino antisense oligonucleotides demonstrates that timing of gene expression is normal in morphants, but these embryos are smaller and exhibit defects in epiboly and patterning of axial and prechordal mesoderm. Analyses of chordin, pax2, krox20, and dlx2 expression in morphants demonstrate that early brain patterning is normal but later organization of hindbrain neurons and development of cranial neural crest are perturbed. Levels of apoptosis in morphants were normal prior to 90% epiboly, but were elevated after 10 h post-fertilization (hpf). Apoptosis does not account for early patterning defects of axial mesoderm, but likely contributes to overall reduction in embryo size. Phylogenetic analysis demonstrates that Sid4 is strikingly similar to the fibronectin binding Ig domains of Perlecan/HSPG2. Overall, our data demonstrate a fundamental role for sid4, possibly as a co-factor in extracellular matrix (ECM) interactions, in processes underlying tissue patterning and organogenesis in a vertebrate.

Naloxone for shock.

BACKGROUND: There is pre-clinical evidence, involving several animal species, suggesting that opioid peptides play a role in the physiopathology of shock (endotoxic, hypovolemic, cardiogenic, spinal, anaphylactic). Many case reports have suggested that naloxone (an opiate antagonist) might be an effective treatment for shock in humans, but others have not supported such a point of view. This controversy led us to undertake a meta-analysis of the available evidence on the efficacy of naloxone as a treatment measure of shock in humans. OBJECTIVES: To evaluate the effectiveness and safety of naloxone in human shock and to estimate the methodological quality of the clinical trials. SEARCH STRATEGY: Computerized bibliographic search up to December 2002, review of references of all papers found on the subject and contact with primary investigators of eligible studies. SELECTION CRITERIA: Randomized controlled trials evaluating naloxone in human shock, regardless of the patient's age (adult, child or neonate). DATA COLLECTION AND ANALYSIS: Three independent reviewers extracted data on study design, intervention, outcome and methodological quality. MAIN RESULTS: Three independent readers reviewed 80 human publications and selected six clinical trials. Overall agreement on study selection was perfect (concordance: 100%). This meta-analysis includes six studies involving 126 patients with septic, cardiogenic, hemorrhagic or spinal shock. Naloxone therapy was associated with statistically significant hemodynamic improvement (odds ratio 0.24; 95% confidence interval [95%CI] 0.09-0.68). The mean arterial pressure was significantly higher in the naloxone groups than in the placebo groups (weighted mean difference: +9.33 mmHg; 95%CI 7.07-11.59). No heterogeneity was found for this outcome. The death rate was lower in the naloxone group (odds ratio 0.59; 95%CI 0.21-1.67) but this was consistent with the play of chance. A significant heterogeneity for the latter outcome was detected (p<0.05). REVIEWER'S CONCLUSIONS: Naloxone improves blood pressure, especially mean arterial blood pressure. However, the clinical usefulness of naloxone to treat shock remains to be determined, and additional randomized controlled trials are needed to assess its usefulness.

Decision making and end-of-life care in critically ill children.

OBJECTIVES: 1) To comment on the medical literature on decision making regarding end-of-life therapy, 2) to analyze the data on disagreement about such therapy, including palliative care, and withholding and withdrawal practices for critically ill children in the pediatric intensive care unit (PICU), and 3) to make some general recommendations. DATA SOURCES AND STUDY SELECTION: All papers published in peer-reviewed journals, and all chapters on end-of-life therapy, or on conflict between parents and caregivers about end-of-life decisions in the PICU were retrieved. RESULTS: We found three case series, three systematic descriptive studies, two qualitative studies, four surveys, and many legal opinions, editorials, reviews, guidelines, and book chapters. The main determinants of end-of-life decisions are the child's age, premorbid cognitive condition and functional status, pain or discomfort, probability of survival, and quality of life. Risk factors in persistent conflict between parents and caregivers about end-of-life care include a grave underlying condition or an unexpected and severe event. CONCLUSION: Making decisions about end-of-life care is a frequent event in the PICU. Children may need both intensive care and palliative care concurrently at different stages of their illness. Disagreements are more likely to be resolved if the root cause of the conflict is better understood.

Ribavirin in ventilated respiratory syncytial virus bronchiolitis. A randomized, placebo-controlled trial.

We undertook a prospective, double-blind, placebo-controlled trial to resolve the question of the clinical effectiveness of ribavirin in previously well infants who require ventilation for respiratory distress secondary to respiratory syncytial virus (RSV) bronchiolitis. Aerosol ribavirin or NaCl 0.9% was administered within 24 h of initiation of ventilation, 18 h/d, for a maximum of 7 d or until extubation. From March 1994 to March 1997, 42 children were randomized and 41 patients were retained for analysis. Baseline characteristics of each group-ribavirin and placebo (20:21)-were not significantly different with respect to age (62.5 +/- 35.9 versus 62.7 +/- 30.9 d), sex, weight, and length of ventilation pre-aerosol. "Intent to treat" outcome analysis found no significant differences in the length of the following: ventilation (102.16 +/- 65.26 versus 126.28 +/- 78.72 h; p = 0.29), aerosol therapy, stay in the intensive care unit, total oxygen therapy, and hospitalization. The aerosols were well tolerated and no deaths occurred. This trial demonstrates the lack of effectiveness of aerosolized ribavirin in reducing the length of ventilation and course of illness in infants with no underlying illness ventilated for respiratory distress secondary to RSV bronchiolitis.

Therapy of shock with naloxone: a meta-analysis.

OBJECTIVES: To evaluate the effectiveness of naloxone in human shock; and to estimate the methodologic quality of the clinical trials. DATA SOURCES: Computerized bibliographic search on MEDLINE covering the period from January 1979 to July 1996, review of references of all papers found on the subject, and contact with primary investigators of eligible studies. STUDY SELECTION: To be included in this study, a paper should be a randomized, clinical trial published in a peer-reviewed journal evaluating naloxone in human shock, regardless of the patient's age (adult, child, neonate). Three independent readers reviewed 61 human publications and selected five clinical trials. Overall agreement on study selection was perfect (concordance: 100%). We excluded a posteriori two studies whose authors were unable to provide us with the raw data to complete contingency tables. This meta-analysis deals with three studies including 61 patients with septic shock. DATA EXTRACTION: Three independent reviewers extracted data on study design, intervention, outcome, and methodologic quality. The intraclass correlation coefficient was 0.7. The quality score of each study was 48, 60, and 61, on a scale of 104. DATA SYNTHESIS: Naloxone therapy was associated with statistically significant hemodynamic improvement (typical odds ratio: 0.241; 95% confidence interval: 0.08 to 0.68). The overall effect size was 0.89. However, a publication bias was possible. The case fatality rate was not decreased by naloxone (typical odds ratio: 0.60; 95% confidence interval: 0.21 to 1.67); a chi-square analysis detected significant heterogeneity for the latter outcome (p < .05). CONCLUSIONS: Naloxone improves blood pressure. However, the clinical usefulness of naloxone to treat shock remains to be determined and additional randomized clinical trials are needed to assess its usefulness.

Clinically significant upper gastrointestinal bleeding acquired in a pediatric intensive care unit: a prospective study.

OBJECTIVES: To determine the incidence, risk factors, and complications associated with or attributable to clinically significant upper gastrointestinal (GI) bleeding acquired in a pediatric intensive care unit (ICU). METHODS: Prospective, descriptive epidemiologic study in a multidisciplinary pediatric ICU of a tertiary-care university hospital. Upper GI bleeding was considered to be present if hematemesis occurred or blood was present in the gastric tube. An upper GI bleed was qualified as clinically significant if two or three reviewers independently assessed that at least one of the six complications considered for analysis was attributable to the upper GI bleed. RESULTS: A cohort of 1114 consecutive admissions was enrolled; 108 (9.7%) were excluded mostly (37.0%) because they already had an upper GI bleed at entry to the pediatric ICU. The final sample included 1006 admissions (881 patients); 103 upper GI bleeds (10.2%) were diagnosed, including 16 clinically significant upper GI bleeds (1. 6%). Complications attributed to an upper GI bleed included: decreased hemoglobin concentration (10 cases), transfusion (10), hypotension (3), and surgery (1). Three independent risk factors for clinically significant upper GI bleeding were retained by multivariate analysis: respiratory failure, coagulopathy, and pediatric risk of mortality score >/=10. Nine of the 16 cases (56. 3%) with clinically significant upper GI bleeding had three risk factors, 14 (87.5%) had two, and 1 (6.3%) had none. CONCLUSIONS: Clinically significant upper GI bleeds are rare in critically ill children. Prophylaxis to prevent them may be limited to patients who present with at least two risk factors.

trans-3-Benzyl-4-hydroxy-7-chromanylbenzoic acid derivatives as antagonists of the leukotriene B4 (LTB4) receptor.

The SAR of a series of 2-(7-chromanyl)benzoic acids has been investigated with the aim of identifying potent and selective LTB4 receptor antagonists that maintain potency in complex biological fluids. We found optimal activity in derivatives with electron-withdrawing groups in the benzoic acid ring and with an unsubstituted C-3 benzyl group on the chromanol nucleus. While compounds containing a 3-(4-phenyl)benzyl chromanol substituent were potent LTB4 receptor antagonists, the increased lipophilicity imparted by the additional phenyl substituent led to decreased potency in the presence of plasma proteins. From among the potent compounds identified, CP-195543, the 5'-trifluoromethyl 3-benzyl chromanol, was selected for development.

Nosocomial pneumonia and tracheitis in a pediatric intensive care unit: a prospective study.

We conducted a prospective study in the multidisciplinary pediatric intensive care unit (pediatric ICU) of a tertiary-care university hospital in order to determine the incidence, risk markers, risk factors, and complications related to bacterial nosocomial pneumonia (BNP) and tracheitis (BNT) in children. A cohort of 1,114 consecutive admissions to the pediatric ICU was enrolled over a 56-wk period; 154 cases were excluded mostly (75%) because they already had a respiratory infection at entry. The final sample included 960 admissions (831 patients). Diagnosis of BNP or BNT was based on Centers for Disease Control of Atlanta criteria using a consensus method involving three experts, who also attributed complications to BNP and BNT. A total of 29 BNP and BNT (3.0%; 95% CI: 1.1 to 4.1%) were diagnosed (BNP: 1.2%, 95% CI: 0.7 to 1.9%; BNT: 1.8%, 95% CI: 0.8 to 2.6%). Three factors were retained by multivariate analysis as independent risk factors or markers for BNP (immunodeficiency, immunosuppression, and neuromuscular blockade), and two for BNT (head trauma and respiratory failure). Gram-negative bacteria and Staphylococcus aureus were the microorganisms most frequently found in the tracheal aspirates. Prescription of antibiotics was commonly attributable to BNP (75%) and BNT (59%). Death, as well as multiple organ system failure, resulted from BNP in 8% of cases, but never from BNT. In BNT, the reintubation rate was 24%. Nosocomial bacterial respiratory infections are rare in critically ill children. However, BNP causes significant complications, and more attention should be focused on BNT in the critically ill child.

Identification and characterisation of a human calmodulin-stimulated phosphodiesterase PDE1B1.

A cDNA encoding a calmodulin-stimulated 3',5'-cyclic nucleotide phosphodiesterase (PDE) was isolated from a human brain cDNA library. The cDNA, designated HSPDE1B1, encoded a protein of 536 amino acids that shared 96% sequence identity with the bovine "63 kDa" calmodulin-stimulated PDE. The recombinant protein had cyclic nucleotide phosphodiesterase activity that was stimulated approximately 2-fold by Ca2+/calmodulin and preferred cGMP as substrate. In addition, the enzymatic activity of HSPDE1B1 was inhibited by phosphodiesterase inhibitors with potencies similar to that displayed toward the bovine PDE1 enzymes: IBMX approximately equal to 8-methoxymethyl-IBMX > vinpocetine approximately equal to zaprinast > cilostamide > rolipram. HSPDE1B1 mRNA was found predominantly in the brain. Lower mRNA levels were found in heart and skeletal muscle. In situ hybridisation of brain revealed expression of HSPDE1B1 predominately in neuronal cells of the cerebellum, hippocampus and caudate. The HSPDE1B1 gene was mapped to human chromosome 12. A partial genomic sequence of HSPDE1B1 was isolated and shown to contain two splice junctions that are conserved in the rat PDE4 and the Drosophila dunce genes.

Epidemiology of sepsis and multiple organ dysfunction syndrome in children.

STUDY OBJECTIVES: To determine the cumulated incidence and the density of incidence of systemic inflammatory response syndrome (SIRS), sepsis, severe sepsis, septic shock, and multiple organ dysfunction syndrome (MODS) in critically ill children; to distinguish patients with primary from those with secondary MODS. DESIGN: Prospective cohort study. SETTING: Pediatric ICU of a university hospital. PATIENTS: One thousand fifty-eight consecutive hospital admissions. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: SIRS occurred in 82% (n=869) of hospital admissions, 23% (n=245) had sepsis, 4% (n=46) had severe sepsis, 2% (n=25) had septic shock; 16% (n=168) had primary MODS and 2% (n=23) had secondary MODS; 6% (n=68) of the study population died. The pediatric risk of mortality (PRISM) scores on the first day of admission to pediatric ICU were as follows: 3.9 +/- 3.6 (no SIRS), 7.0 +/- 7.0 (SIRS), 9.5 +/- 8.3 (sepsis), 8.8 +/- 7.8 (severe sepsis), 21.8 +/- 15.8 (septic shock); differences among groups (p=0.0001), all orthogonal comparisons, were significant (p<0.05), except for patients with severe sepsis. The observed mortality for the whole study population was also different according to the underlying diagnostic category (p=0.0001; p<0.05 for patients with SIRS and those with septic shock, compared with all groups). Among, patients with MODS, the difference in mortality between groups did not reach significance (p=0.057). Children with secondary MODS had a longer duration of organ dysfunction (p<0.0001), a longer stay in pediatric ICU after MODS diagnosis (p<0.0001), and a higher risk of mortality (odds ratio, 6.5 [2.7 to 15.9], p<0.0001) than patients with primary MODS. CONCLUSIONS: SIRS and sepsis occur frequently in critically ill children. The presence of SIRS, sepsis, or septic shock is associated with a distinct risk of mortality among critically ill children admitted to the pediatric ICU; more data are needed concerning children with MODS. Secondary MODS is much less common than primary MODS, but it is associated with an increased morbidity and mortality; we speculate that distinct pathophysiologic mechanisms are involved in these two conditions.

The in vitro and in vivo pharmacologic activity of the potent and selective leukotriene B4 receptor antagonist CP-105696.

CP-105696, (+)-1-(3S,4R)-[3-(4-phenyl-benzyl)-4-hydroxy-chroman-7-yl] cyclopentane carboxylic acid, is a structurally novel, selective and potent leukotriene B4 (LTB4) receptor antagonist. In vitro, CP-105696 inhibited [3H]LTB4 (0.3 nM) binding to high-affinity LTB4 receptors on human neutrophils with an IC50 value of 8.42 +/- 0.26 nM. Scatchard analyses of [3H]LTB4 binding to these high-affinity receptors indicated that CP-105696 acted as a noncompetitive antagonist. CP-105696 inhibited human neutrophil chemotaxis mediated by LTB4 (5 nM) in a noncompetitive manner with an IC50 value of 5.0 +/- 2.0 nM. Scatchard analyses of [3H]LTB4 binding to low-affinity receptors on neutrophils indicated that CP-105696 acted as a competitive antagonist at this receptor, and inhibition of LTB4-mediated CD11b upregulation on human neutrophils was competitively inhibited by CP-105696 (pA2 = 8.03 +/- 0.19). CP-105696 at 10 microM did not inhibit either human neutrophil chemotaxis or CD11b upregulation mediated through alternate (i.e., C5a, IL-8, PAF) G-protein coupled chemotactic factor receptors. In isolated human monocytes, LTB4 (5 nM)-mediated Ca++ mobilization was inhibited by CP-105696 with an IC50 value of 940 +/- 70 nM. In vivo, after oral administration, CP-105696 blocked neutrophil and eosinophil infiltration in cavine dermis mediated by either LTB4 or arachidonic acid with ED50 values of 0.3 +/- 0.1 mg/kg. 12(R)-Hydroxyeicosatetraenoic acid-mediated neutrophil infiltration was blocked by 76.4 +/- 14.8% at 3 mg/kg.(ABSTRACT TRUNCATED AT 250 WORDS)

Leukotriene B4 plays a critical role in the progression of collagen-induced arthritis.

Leukotriene B4 (LTB4) is a product of the 5-lipoxygenase pathway of arachidonic acid metabolism. LTB4 is a potent chemotactic factor for neutrophils and has been postulated to play an important role in a variety of pathological conditions including rheumatoid arthritis (RA), psoriasis, and inflammatory bowel disease. The role of LTB4 in such diseases has not yet been defined but in this paper we provide direct evidence that LTB4 plays a critical role in a murine model of RA. CP-105,696, (+)-1-(3S,4R)-[3-(4-phenylbenzyl)- 4-hydroxychroman-7-yl]cyclopentane carboxylic acid, is an LTB4 receptor antagonist that inhibits LTB4 binding to human neutrophil membranes with an IC50 of 3.7 nM and inhibits LTB4-induced chemotaxis of these cells with an IC50 of 5.2 nM. CP-105,696 inhibits LTB4-induced neutrophil influx in mouse skin when administered orally with an ED50 of 4.2 mg/kg. CP-105,696 had a dramatic effect on both the clinical symptoms and histological changes of murine collagen-induced arthritis when administered at doses of 0.3-10 mg/kg. Inhibition was not associated with suppression of the humoral immune response to collagen and was equally effective if drug treatment was commenced just prior to the onset of arthritis or throughout the experiment. These results suggest that LTB4 receptor antagonists may be effective therapeutic agents for the treatment of RA.

Timing and predictors of death in pediatric patients with multiple organ system failure.

OBJECTIVES: To describe the timing of onset of organ system failure, multiple organ system failure diagnosis, and the subsequent death in children admitted to a pediatric intensive care unit (ICU). Second, to identify independent risk markers of death in pediatric patients with multiple organ system failure. DESIGN: Review of a database. SETTING: Pediatric ICU within a tertiary care center. PATIENTS: We analyzed the pediatric ICU course of 777 consecutive patients aged < 18 yrs. MEASUREMENTS AND MAIN RESULTS: Eighty-five (10.9%) of 777 children had multiple organ system failure, defined as the simultaneous occurrence of at least two organ system failures. Of 85 children, 37 (43.5%) were postoperative cardiac surgery patients and 48 (56.5%) patients were in the ICU for other reasons. The diagnostic criteria for multiple organ system failure were met on the day of admission by 73 (86%) of 85 patients. The maximum number of organ system failures occurred within 72 hrs in 74 (87%) children. The mortality rate for all patients with multiple organ system failure was 50.6%. Thirty-eight (88.4%) of deaths occurred within 7 days after the diagnosis of multiple organ system failure. Survival analysis was comparable for both postoperative cardiac surgery patients and patients with other diagnoses. Multivariate analysis identified three factors as independent risk markers of death in pediatric patients with multiple organ system failure: maximum number of simultaneous organ system failures during the pediatric ICU stay: odds ratio, 55.9 (95% confidence interval, 7.9 to 396.1); age < or = 12 months: odds ratio, 17.1 (95% confidence interval, 1.8 to 158.7); and the Pediatric Risk of Mortality (PRISM) score on the day of admission: odds ratio, 1.25 (95% confidence interval, 1.1 to 1.5). CONCLUSIONS: The mortality rate associated with multiple organ system failure in pediatric patients is high. The maximum number of simultaneous organ system failures during pediatric ICU stay, age < or = 12 months, and the PRISM score on the day of admission are independent risk markers of death. Diagnosis of multiple organ system failures, development of maximum number of organ system failures, and deaths occur remarkably early after pediatric ICU admission; the rationale for using prophylactic therapy under such circumstances is unclear.

Admissions to a pediatric intensive care unit for status epilepticus: a 10-year experience.

OBJECTIVE: To characterize the etiology, course, and prognosis in children admitted to a pediatric intensive care unit (ICU) for status epilepticus. DESIGN: Retrospective, descriptive study. SETTING: Pediatric ICU in a university hospital. PATIENTS: One hundred forty-seven children admitted with status epilepticus. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Status epilepticus was defined as a prolonged (> 30 mins) or repeated tonic or tonic-clonic seizure with a persistent altered state of consciousness. Over 10 yrs, 147 children 0 to 16 yrs of age (median 1; mean 3.4 +/- 3.9 [SD]) were admitted to a pediatric ICU for, or with, 153 episodes of status epilepticus. Status epilepticus was caused most often by epilepsy (n = 52), atypical febrile convulsions (n = 21), bacterial meningitis (n = 20), encephalitis (n = 20), intoxication (n = 8), or a metabolic disorder (n = 12). Two infants, 1 and 3 months of age, and a patient with intoxication by isoniazid, responded to pyridoxine. Among 114 previously normal children, 34 patients displayed a new neurologic problem on discharge from the ICU, among whom, 68% (23/34) still had some neurologic abnormality 1 yr after the episode of status epilepticus. Nine patients died during their ICU stay, mostly from underlying disease rather than from the status epilepticus itself. A normal neurologic status before status epilepticus and age < 4 yrs seem to be markers of good prognosis, while encephalitis and meningitis appear to be markers for morbidity and mortality. CONCLUSIONS: Most cases of status epilepticus were caused by epilepsy, atypical febrile seizure, encephalitis, meningitis, or metabolic disease. The mortality rate during the ICU stay was 6%. The prognosis was good in most surviving cases, more so if the neurologic development of the child was normal before the status epilepticus.

C5a as a model for chemotactic factor-stimulated tyrosine phosphorylation in the human neutrophil.

Human neutrophils were exposed to the chemotactic factors C5a, FMLP, IL-8, leukotriene B4, and PAF, for 30 s, and subsequently analyzed for protein tyrosine phosphorylation by immunoblotting whole cell lysates with a polyclonal antiphosphotyrosine Ab. All chemotactic factors caused the rapid de novo tyrosine phosphorylation of a broad band of approximately 120 kDa and increased the phosphotyrosine content of several other proteins, including two with molecular masses of 60 and 56 kDa that were present in the unstimulated neutrophil. Tyrosine phosphorylation was evident as early as 10 s after stimulation and was maintained for 1 to 3 min before dephosphorylation occurred. The extent of tyrosine phosphorylation was dependent on the concentration of chemotactic factor, with stimulation observed at concentrations as low as 10 to 100 nM. To investigate the pathway used by chemotactic factors to transduce this signal, neutrophils were treated with PMA. PMA also stimulated tyrosine phosphorylation in the neutrophil but with a slower response time and a different pattern of affected proteins. Additional experiments suggested that tyrosine phosphorylation is involved in the regulation of the neutrophil respiratory burst because the tyrosine kinase inhibitor, herbimycin A, inhibited C5a-induced protein tyrosine phosphorylation and also prevented C5a- and FMLP-induced superoxide anion production. Herbimycin A also inhibited PMA-induced tyrosine phosphorylation and superoxide anion production. To confirm that the ability to stimulate tyrosine phosphorylation was intrinsic to the C5a receptor, tyrosine phosphorylation was examined in both undifferentiated U937 cells (C5a receptor negative) and cAMP differentiated U937 cells (C5a receptor positive). C5a induced tyrosine phosphorylation only in differentiated U937 cells. Analysis of the C5a receptor mRNA using the PCR confirmed its presence in differentiated and its absence in undifferentiated U937 cells. Therefore, C5a stimulates tyrosine phosphorylation via a receptor-mediated mechanism and U937 cells provide a system in which G-coupled receptor-mediated tyrosine phosphorylation can be investigated.

Convulsions and hypertension in children: differentiating cause from effect.

OBJECTIVE: To determine if the magnitude of blood pressure (BP) increase could differentiate convulsion caused by a hypertensive crisis from a primary convulsive disorder, which itself increases BP. DESIGN: Retrospective analysis. SETTING: Admission to a pediatric intensive care unit (ICU) within a tertiary care center. PATIENTS: All children with hypertensive crisis admitted to the pediatric ICU from 1976 to 1990 were studied. Thirty-eight episodes occurred in 36 patients. The charts of children admitted for status epilepticus from 1976 to 1986 were also reviewed. One hundred and fifty-three episodes occurred in 145 patients. MEASUREMENTS AND MAIN RESULTS: BP values at entry to the pediatric ICU in patients with hypertensive crisis were compared with the highest BP values obtained within an hour after cessation of convulsion in 120 patients admitted for status epilepticus. The Z scores for BP, adjusted for age and sex, were compared. The BP values for children in hypertensive crisis with or without convulsions were by far greater than the BP values observed in patients in status epilepticus (p < .0001). For a patient in the postictal phase, a BP > or = 4.0 SD above the mean for age and sex predicted with 78% probability the presence of a hypertensive crisis requiring emergency treatment. If the BP was < 4 SD below the mean, the possibility of a hypertensive crisis was excluded (negative-predictive value 100%). CONCLUSIONS: Children with hypertensive crisis, as well as children with status epilepticus, can present with a high BP. In a postictal patient, the magnitude of BP increase is a useful clinical parameter to exclude a hypertensive crisis that requires specific treatment of the BP.