Polymeric mannosides prevent DC-SIGN-mediated cell-infection by cytomegalovirus.

Human cytomegalovirus (HCMV) is a beta-herpesvirus with a high prevalence in the population. HCMV is asymptomatic for immunocompetent adults but is a leading cause of morbidity for new born and immunocompromised patients. It was recently shown that the envelope glycoprotein B (gB) of HCMV interacts with the Dendritic Cell-Specific ICAM-3 Grabbing Non integrin (DC-SIGN) to infect the host. In this work we developed a set of DC-SIGN blockers based on mono-, di-, tetra and polyvalent mannosides. The multivalent mannosides were designed to interact with the carbohydrate recognition domains of DC-SIGN in a chelate or bind and recapture process, and represent the first chemical antiadhesives of HCMV reported so far. Polymeric dextrans coated with triazolylheptylmannoside (THM) ligands were highly potent, blocking the gB and DC-SIGN interaction at nanomolar concentrations. The compounds were further assessed for their ability to prevent the DC-SIGN mediated HCMV infection of dendritic cells. A dextran polymer coated with an average of 902 THM ligands showed an outstanding effect in blocking the HCMV trans-infection with IC50 values down to the picomolar range (nanomolar when expressed in THM concentration). Each THM moiety on the polymer surpassed the antiadhesive effect of the methylmannoside reference by more than four orders of magnitude. The compound proved non-cytotoxic at the high concentration of 2 mM and therefore represents an interesting antiadhesive candidate against HCMV and potentially against other virus hijacking dendritic cells to infect the host.

Second generation of thiazolylmannosides, FimH antagonists for E. coli-induced Crohn's disease.

The anti-adhesive strategy, consisting of disrupting bacterial attachment to the host cells, is widely explored as an alternative to antibiotic therapies. Recently, thiazolylmannosides (TazMans) have been identified as strong anti-adhesives of E. coli strains implied in the gut inflammation of patients with Crohn's disease. In this work, we developed a second generation of TazMans with improved chemical stability. The anomeric nitrogen was substituted by short linkers and the compounds were assessed against the bacterial adhesin FimH and the clinically isolated LF82 E. coli strain in four in vitro assays. The results obtained on the FimH adhesin alone and the whole bacteria enabled the identification of a candidate for further in vivo evaluations.

Inhibition profiles of mono- and polyvalent FimH antagonists against 10 different Escherichia coli strains.

Mono- and polyvalent ligands with strong affinities for the mannose-binding adhesin FimH were synthesised, and their anti-adhesive properties against ten E. coli strains were compared in two cell-based assays. The compounds were assessed against the non-pathogenic E. coli K12 and nine strains isolated by coproculture or from patients with osteoarticular infections (OIs), Crohn's disease (CD) and urinary tract infections (UTIs). The results showed that the compounds could inhibit the whole set of bacterial strains but with marked differences in terms of effective concentrations. The relative inhibitory potency of the monovalent compounds was also conserved for the ten strains and in the two assays. These results clearly suggest that a potent monovalent anti-adhesive assessed on a single E. coli strain will probably be effective on a broad range of strains and may treat diverse E. coli infections (OIs, CD and UTIs). In contrast, the polyvalent compounds showed a significant strain-dependancy in preventing E. coli attachment to intestinal cells. The multivalent antiadhesive effect may therefore vary depending on the E. coli strain tested.

Office management of minor wounds.

OBJECTIVE: To review office interventions for minor wounds not requiring sutures, such as abrasions, bites, and lacerations. QUALITY OF EVIDENCE: Most information on minor wound management comes from descriptive studies. Few comparative studies examine the effectiveness of topical antisepsis for minor wounds. Several clinical trials have demonstrated that tissue adhesives produce short- and long-term cosmetic results equivalent to those achieved with suture materials. MAIN MESSAGE: Sterile saline is the least toxic solution for wound irrigation. Chlorhexidine (2%) and povidone iodine (10%) have been the most investigated antiseptic solutions. Systemic antibiotics are unnecessary for wounds unlikely to be infected. All bite wounds require special attention. Primary closure of bite wounds is indicated in certain circumstances: less than 12-hour-old nonpuncture wounds, uninfected wounds, and low-risk lesions (such as on the face). In spite of their many advantages, skin tapes should be used for low-tension wounds only. The popularity of tissue adhesives has greatly increased. Since the advent of newer products (with increased bonding strength and flexibility), adhesives are used to manage most lacerations except those in areas of high tension (e.g., joints) and on mucosal surfaces. CONCLUSION: Minor wounds not requiring sutures can be managed easily in the office.

Quantitative assays of the amount of diethylenetriaminepentaacetic acid conjugated to water-soluble polymers using isothermal titration calorimetry and colorimetry.

The level of conjugation of diethylenetriaminepentaacetic acid (DTPA) to the polysaccharide sodium hyaluronan (HA) has been measured by a colorimetric assay, isothermal titration calorimetry (ITC), and (1)H NMR spectroscopy. The colorimetric assay is based on the red shift, upon complexation with gadolinium ion (Gd3+), of the wavelength of maximum absorption of the dye arsenazo III. It can be performed in a few minutes using as little as 10 microg of polymer with a detection limit of approximately 0.03 mmol of DTPA (gram of polymer)-1. The ITC measurements yield values of the amount of DTPA linked to HA identical to those obtained by colorimetry. The levels of DTPA conjugation calculated by integration of signals at 3.1-3.2 ppm (DTPA protons) and at 2.0 ppm (HA acetamide protons) in the 1H NMR spectrum of HA-DTPA are consistently overestimated by a factor of approximately 2, compared to the data obtained by ITC and colorimetry. The longer relaxation times of protons of the polymer backbone, compared to those of protons attached to the freely moving DTPA side-chains may account for the discrepancy.

Predictive factors for short-term symptom persistence in children after emergency department evaluation for constipation.

BACKGROUND: Children with symptoms and signs of constipation are commonly assessed in pediatric emergency departments (EDs). Little is known about their outcome following the ED visit. OBJECTIVES: To describe the clinical characteristics of children presenting to the ED with constipation and the ED interventions; to measure short-term symptom resolution at 48 hours and 7 days after the ED visit; and to identify predictive factors associated with poor symptom resolution at 48 hours and 7 days after the ED visit. DESIGN/METHODS: Cohort study conducted between July 10, 1997, and September 10, 1997, in a tertiary care pediatric hospital ED. All children (aged 1-18 years) with idiopathic constipation were included. Constipation was diagnosed if there were at least 2 of the following: abdominal pain, infrequent bowel movements, hard feces, fecal soiling, pain on defecation, and/or clinical evidence of excessively retained feces. Data on the presenting symptoms, signs, and ED treatment plan were collected on study enrollment and then in 2 standardized 10-minute telephone interviews at 48 hours and 7 days after the ED visit. At each follow-up, patient disposition was measured and dichotomized based on symptom resolution to "improved" vs "not improved." The presenting features and ED management were compared between groups using chi(2) analyses and t tests. RESULTS: Consent and full questionnaire completion was obtained in 102 children. The mean + SD age was 6.5 + 3.8 years; 47 (46%) were male. The predominant presenting symptom was abdominal pain (83 [81%]); the most frequent sign was palpable abdominal stool (67 [66%]). A high-fiber diet (75 [74%]) and mineral oil (48 [47%]) were prescribed most frequently. Enemas were given to 64 (63%) of the children. Improvement was found in 32 (31%) of the children at 48 hours and in the majority at 7 days (77 [75%]). Risk factors for poor symptom resolution at both 48 hours and 1 week included: female sex (odds ratio [OR] = 2.6; 95% confidence interval [CI] = 1.0 6.6); history of recurrent abdominal pain (OR = 2.8; 95% CI = 1.2-6.5); duration of primary presenting symptom longer than 2 days (OR = 2.4; 95% CI = 1.0-6.4); and history of medical visits for the same symptom (OR = 2.3; 95% CI = 1.0-5.3). There was no difference in outcome based upon ED treatment (enema vs oral or no therapy) (OR = 1.0; 95% CI = 0.4-2.3). CONCLUSIONS: Most children with constipation evaluated in the ED have acute symptoms and rapid improvement, regardless of presentation characteristics or ED management. In this study, 4 risk factors for poor outcome were found consistently at 48 hours and 7 days. This subgroup of children deserve closer clinical attention. Emergency department therapy did not influence short-term symptom resolution. Further studies are warranted to examine the effects of therapy for constipation in the ED setting. Arch Pediatr Adolesc Med. 2000;154:1204-1208.

Utilization analysis of an observation unit for children with asthma.

BACKGROUND: Short-stay observation unit (OU) care for children with asthma has the potential to reduce hospitalization rates for this common pediatric condition. In the effort to increase the efficiency of such a unit, knowledge of predictive factors for successful discharge is important. OBJECTIVES: 1) To define clinical predictive factors determined at the time of initial presentation in the emergency department (ED) that would identify which children with asthma are most likely to be successfully discharged from an OU. 2) To compare the management provided in the initial 3 hours upon arrival at the ED between the children who are eventually successfully discharged from an OU to those who require an inpatient admission. 3) To compare the length of stay in the OU between the patients who eventually go home to those who require an inpatient admission. DESIGN: Case control study. SETTING: Urban, tertiary-care pediatric ED. PARTICIPANTS: From a collected database of all patients with asthma 1 to 18 years of age, presenting to the ED from July 1, 1993 to June 30, 1994 (n = 2248), a random sample of 350 patients was identified. All children meeting the definition of "case" or "control" from this sample were included. Cases were defined as children with asthma who were successfully discharged after a stay in the OU. Controls were defined as children with asthma who were not successfully discharged; that is, children who required subsequent inpatient admission. RESULTS: Of the 350 children with asthma in the randomly selected subset sample, 47 cases and 21 controls were identified. In both cases and controls, patients had similar characteristics regarding mean age, sex, mean weight, previous history of asthma, and mean length of illness. The use of medications in the 24 hours prior to presentation to the ED was similar between both groups. No differences were found in the mean respiratory rate upon presentation between the cases and the controls (40/min vs. 44/min; P = 0.2), mean oxygen saturation (95 vs. 94%; P = 0.4). However, there was a significant difference in the requirement of supplemental oxygen between cases and controls (15 vs. 43%; P = 0.01; OR = 0.23:0.07 to 0.76). No further differences were found in the first 3 hours of ED management. The number of albuterol and ipratropium nebulizations was similar. The use, dosage, and timing of systemic steroids were also similar between the groups. The cases remained in the OU for a shorter period of time (8.7 hours vs 9.2 hours; 95% C.I.: -2.8 to 1.8) than the controls. CONCLUSION: No clinical predictive factors determined at the time of arrival to the ED were identified for children with asthma who were successfully discharged from the OU except for a lesser need of oxygen supplementation. The patients observed in the OU had similar management in the initial 3 hours of arrival and similar length of stay in the OU, regardless of their disposition outcome. Maximal OU efficiency remains limited by the lack of clear predictive factors for successful discharge. Further study in this area is indicated.

Effect of a pediatric observation unit on the rate of hospitalization for asthma.

STUDY OBJECTIVE: To determine the asthma admission rate and the rate of repeat visits to the emergency department for asthma within 72 hours before and after the introduction of an observation unit (OU). When necessary, admission to the ward from the OU is usually made within 12 hours. METHODS: We conducted a before-and-after study with retrospective data collection in an urban tertiary care pediatric ED. Our subjects were patients aged 1 to 18 years who presented to the ED with asthma. The pre-OU group comprised patients seen between July 1, 1991, and June 30, 1992, before the opening of the OU. The post-OU group consisted of children seen between July 1, 1993, and June 30, 1994, after the opening of the OU. RESULTS: The pre- and post-OU groups had 1,979 and 2,248 asthma visits, respectively. The admission rate decreased from 31% in the pre-OU group to 24% in the post-OU group (P < .01). The frequency of inpatient admissions of less than 24 hours decreased from 17% in the pre-OU group to 10% in the post-OU group (P < or = 01). The rate of repeat ED visits within 72 hours was 3% in the pre-OU group and 5% in the post-OU group (P = .01). CONCLUSION: The use of an OU in the ED was associated with a reduction in the hospitalization rate for children with acute asthma exacerbation. However, we also noted an increased rate of repeat visits to the ED after the introduction of the OU.

Synthesis of 3 alpha- and 3 beta-dimers from selected bile acids.

New dimers of bile acids have been synthesized by linking the hydroxyl groups on C3 of the steroid skeleton with a spacer via the formation of ester or ether bonds. 3 alpha-Dimers of lithocholic acid and cholic acid were prepared by forming ester linkages between the C3 hydroxyl group and dicarboxylic acids of different lengths, i.e., suberoyl chloride (eight carbons) and sebacoyl chloride (ten carbons). These dimers were obtained in three steps with an overall yield of about 70%. Regioselective hydrolysis of the methyl ester protecting groups on the bile acids was carried out successfully under mild alkaline conditions (aqueous lithium hydroxide with tetrahydrofuran). A 3 beta-dimer of lithocholic acid has also been synthesized by linking the C3 positions of two bile acids with diethylene glycol by the formation of ether linkages. The carboxylic acid groups of the bile acid dimer can be liberated by the removal of the methyl ester protecting groups.

Unusual cause of seizure.

INTRODUCTION: This case report of camphor ingestion in a 15-month-old child illustrates the potential toxicity of a common household product. Details of the patient presentation are reported along with a review of the literature. METHODS: Patient information was collected using the records of Poison Control, the Emergency Department, and the Health Records at the Hospital for Sick Children in Toronto, Ontario, Canada. A comprehensive review of the literature was conducted using the MEDLINE database for the time period 1966 to April 1995. DISCUSSION: Oral ingestion of camphor is unusual, given that these products have both unpleasant taste and texture. This patient ingested 70 ml of an over-the-counter medicated ointment containing 4.73% camphor, 2.6% menthol, and 1.2% eucalyptus oil. While the concentration of camphor in this product is low, an estimated 280 mg/kg of camphor was consumed. With significant ingestion of camphor (> 50 mg/kg), neurologic toxicity is common. In this patient, prolonged generalized tonic-clonic seizure activity was noted approximately two hours post single acute ingestion of camphor. This delay in onset of seizure activity is atypical, as seizures have previously been noted to occur in the 90 minutes following ingestion. CONCLUSION: Readily available medicated ointments containing camphor have potential for serious or fatal consequences when ingested by children.

Pulmonary and systemic immunoregulatory changes during the development of experimental asbestosis.

Initial studies on the effects of low dose exposure to asbestos on pulmonary and systemic immune responses have revealed a bi-phasic pattern characterized by an early enhancement followed by inhibition of lymphocyte responses to several mitogens. In the present study, we sought to define the cellular and humoral factors, responsible for the observed effects. The early enhancement of peripheral blood and pulmonary lymphocyte responses to mitogens may be due, at least in part, to the loss of the inhibitory capacity of alveolar macrophages from asbestos exposed animals to suppress lymphocyte response. Furthermore, macrophages from low dose exposed animals actually enhanced lymphocytes responses to Con A and PHA. The latter inhibition observed following 6-12 months of exposure may be due to the in vivo generation of suppressor lymphocytes. Unfractionated lymphocytes from blood or alveolar space as well as enriched T cells from high dose exposed animals suppressed the proliferative responses of pulmonary or circulating lymphocytes to PHA and Con A, but not to PWM. Similarly, pre-incubation of normal blood or pulmonary lymphocytes in serum from high dose exposed animals for 24 h induced the appearance of suppressor cell activity in these populations when further tested in a co-culture assay with normal fresh lymphocytes. Taken together, these studies demonstrate the multi-faceted effects of asbestos on the immune system. The eventual fibrogenic process of asbestosis may result from the interplay of several mechanisms, some of which are suggested in this work.

Asbestos-induced lung inflammation. Role of local macrophage-derived chemotactic factors in accumulation of neutrophils in the lungs.

In a recently developed sheep model of progressive low-dose pulmonary exposure to asbestos, initial alveolar lymphocyte and macrophage activation was followed by pulmonary neutrophilia in higher-dose exposed animals. This was observed after 18 months of exposure to intratracheal instillations of asbestos fibers and coincided with progressive alveolitis and decreased lung compliance. Alveolar macrophages from those animals were found to produce a chemotactic factor which attracted in vitro peripheral blood neutrophils. It attracted neutrophils more efficiently from higher-exposure than lower-exposure animals. Supernatants of control macrophages exposed to asbestos in vitro were also chemotactic for PMN. Similarly, bronchoalveolar lavage fluids from the animals showed chemotactic activity for peripheral blood neutrophils. It is suggested that chronic exposure to asbestos activates alveolar macrophages to produce chemotactic factors which in turn attract neutrophils from the vascular compartment and may thus contribute to the inflammatory process in asbestosis.