Heterogeneity of Herpes Simplex Virus Type 2 Seroprevalence From a National Probability Survey In Mexico, 2012.

BACKGROUND: Herpes simplex virus type 2 (HSV-2) seroprevalence and associated infection risk factors show differences by regions and countries. The aims of the study were to determine the HSV-2 seroprevalence and to evaluate the risk factors for HSV-2 in a national representative survey among adolescents and adults in Mexico. METHODS: A cross-sectional study was carried out in Mexico on the basis of the National Health and Nutrition Survey 2012, a national representative survey. Demographic, sexual behavior, reproductive health, and lifestyles indicators were considered in the current study. Participants provided biological samples-dried blood spots-to test for HSV-2 antibodies using enzyme-linked immunosorbent assay and Western blot. Bivariate and multivariate analyses were performed to identify variables associated with HSV-2 infections analyzed by sex. RESULTS: National HSV-2 seroprevalence was 9.9%, 2.4% among adolescents and 11.7% among adults with HSV-2 seroprevalence heterogeneous across the country. Women had 12.2% of antibodies against HSV-2 and men had 7.5%. The factors associated with HSV-2 infection among women were age (45-49 years; odds ratio [OR], 19.8), region (southwest; OR, 3.0), urbanization (urban; OR, 1.9), age at sexual debut (≤14 years; OR, 3.4), education level (any; OR, 3.0), and previous abortion (≥2 abortion; OR, 2.1). Among men, age (45-49 years; OR, 11.7), region (southwest; OR, 3.0), urbanization (urban, odds ratio [OR], 1.7), and HIV care (OR, 7.1) were associated with the infection. CONCLUSIONS: Approximately 10% of Mexicans aged 15 to 49 years had HSV-2 antibodies, with differences by sex, region, education level, urbanization, HIV care, and childbirth, highlighting the relevance of health inequalities in the country: social inequalities seem to matter in terms of the probability of HSV-2 infections.

Different behavior of myeloperoxidase in two rodent amoebic liver abscess models.

The protozoan Entamoeba histolytica is the etiological agent of amoebiasis, which can spread to the liver and form amoebic liver abscesses. Histological studies conducted with resistant and susceptible models of amoebic liver abscesses (ALAs) have established that neutrophils are the first cells to contact invasive amoebae at the lesion site. Myeloperoxidase is the most abundant enzyme secreted by neutrophils. It uses hydrogen peroxide secreted by the same cells to oxidize chloride ions and produce hypochlorous acid, which is the most efficient microbicidal system of neutrophils. In a previous report, our group demonstrated that myeloperoxidase presents amoebicidal activity in vitro. The aim of the current contribution was to analyze in vivo the role of myeloperoxidase in a susceptible (hamsters) and resistant (Balb/c mice) animal models of ALAs. In liver samples of hamsters and mice inoculated intraportally with Entamoeba histolytica trophozoites, the number of neutrophils in ALAs was determined by enzymatic activity. The presence of myeloperoxidase was observed by staining, and its expression and activity were quantified in situ. A significant difference existed between the two animal models in the number of neutrophils and the expression and activity of myeloperoxidase, which may explain the distinct evolution of amoebic liver abscesses. Hamsters and mice were treated with an MPO inhibitor (4-aminobenzoic acid hydrazide). Hamsters treated with ABAH showed no significant differences in the percentage of lesions or in the percentage of amoebae damaged compared with the untreated hamsters. ABAH treated mice versus untreated mice showed larger abscesses and a decreased percentage of damaged amoebae in these lesion at all stages of evolution. Further studies are needed to elucidate the host and amoebic mechanisms involved in the adequate or inadequate activation and modulation of myeloperoxidase.

A review of the proposed role of neutrophils in rodent amebic liver abscess models.

Host invasion by Entamoeba histolytica, the pathogenic agent of amebiasis, can lead to the development of amebic liver abscess (ALA). Due to the difficulty of exploring host and amebic factors involved in the pathogenesis of ALA in humans, most studies have been conducted with animal models (e.g., mice, gerbils, and hamsters). Histopathological findings reveal that the chronic phase of ALA in humans corresponds to lytic or liquefactive necrosis, whereas in rodent models there is granulomatous inflammation. However, the use of animal models has provided important information on molecules and mechanisms of the host/parasite interaction. Hence, the present review discusses the possible role of neutrophils in the effector immune response in ALA in rodents. Properly activated neutrophils are probably successful in eliminating amebas through oxidative and non-oxidative mechanisms, including neutrophil degranulation, the generation of free radicals (O2(-), H2O2, HOCl) and peroxynitrite, the activation of NADPH-oxidase and myeloperoxidase (MPO) enzymes, and the formation of neutrophil extracellular traps (NETs). On the other hand, if amebas are not eliminated in the early stages of infection, they trigger a prolonged and exaggerated inflammatory response that apparently causes ALAs. Genetic differences in animals and humans are likely to be key to a successful host immune response.

Peroxynitrite and peroxiredoxin in the pathogenesis of experimental amebic liver abscess.

The molecular mechanisms by which Entamoeba histolytica causes amebic liver abscess (ALA) are still not fully understood. Amebic mechanisms of adherence and cytotoxic activity are pivotal for amebic survival but apparently do not directly cause liver abscess. Abundant evidence indicates that chronic inflammation (resulting from an inadequate immune response) is probably the main cause of ALA. Reports referring to inflammatory mechanisms of liver damage mention a repertoire of toxic molecules by the immune response (especially nitric oxide and reactive oxygen intermediates) and cytotoxic substances released by neutrophils and macrophages after being lysed by amoebas (e.g., defensins, complement, and proteases). Nevertheless, recent evidence downplays these mechanisms in abscess formation and emphasizes the importance of peroxynitrite (ONOO(-)). It seems that the defense mechanism of amoebas against ONOO(-), namely, the amebic thioredoxin system (including peroxiredoxin), is superior to that of mammals. The aim of the present text is to define the importance of ONOO(-) as the main agent of liver abscess formation during amebic invasion, and to explain the superior capacity of amoebas to defend themselves against this toxic agent through the peroxiredoxin and thioredoxin system.

Effect of phosphatidylcholine-cholesterol liposomes on Entamoeba histolytica virulence.

Trophozoites of Entamoeba histolytica HM-1:IMSS become less virulent after long-term maintenance in axenic cultures. The factors responsible for the loss of virulence during in vitro cultivation remain unclear. However, it is known that in vitro cultivation of amoeba in culture medium supplemented with cholesterol restores their virulence. In this study, we analyzed the effect of adding phosphatidylcholine-cholesterol (PC-Chol) liposomes to the culture medium and evaluated the effect of this lipid on various biochemical and biological functions of E. histolytica HM-1:IMSS in terms of its virulence. The addition of PC-Chol liposomes to the culture medium maintained the virulence of these parasites against hamster liver at the same level as the original virulent E. histolytica strain, even though these amoebae were maintained without passage through hamster liver for 18 months. The trophozoites also showed increased endocytosis, erythrophagocytosis, and carbohydrate residue expression on the amoebic surface. Protease activities were also modified by the presence of cholesterol in the culture medium. These findings indicate the capacity of cholesterol to preserve amoeba virulence and provide an alternative method for the maintenance of virulent E. histolytica trophozoites without the need for in vivo procedures.

Comparing visual performance and useful field of view of older and younger drivers - biomed 2009.

Older licensed drivers are involved in more crash deaths than any other age group. A critical issue in reducing these accident numbers is to improve our understanding of the association between the visual performance of these older drivers and their useful field of view (UFOV) when driving. We estimated driver saccadic amplitudes and fixation durations for ten different traffic scenarios using a driving simulator. Six traffic situations presented dangerous or other relevant events to the drivers, with the other four having no dangerous or relevant events. To estimate saccadic amplitudes and fixation durations, eye position data was analyzed during the five seconds before and five seconds after the traffic situations. Results imply that eye movements, fixation durations and number of fixation change as a function of the visual stimuli presented in each traffic situation. The difference in age was found to be significant for number of fixations and fixation time, but not for the total eye movement. Based on these results, we expressed UFOV as a function of saccadic amplitude between fixation points and durations, and estimated the ranges of a sequence UFOVs during the 10-second period for each traffic situation. Our findings suggests that UFOV radius depends on driving scenario, time of event, age-group, driving course, two factor and three-factor interactions among these variables.

Staphylococcus aureus panniculitis complicating juvenile dermatomyositis.

Panniculitis is a rarely reported manifestation of juvenile dermatomyositis. The 3 previously reported cases of juvenile dermatomyositis and panniculitis were attributed to flare of underlying disease, rather than infection, and were treated with increased immunosuppression. Here we describe a patient with juvenile dermatomyositis who developed panniculitis secondary to Staphylococcus aureus. Patients with juvenile dermatomyositis and panniculitis should have extensive testing for infectious etiologies before increasing their immunosuppressive regimens.

An unusual cause of rectal bleeding and intestinal obstruction in a child with peripheral vascular malformations.

Vascular malformations of the small bowel are rare yet important causes of abdominal pain and rectal bleeding in children. This report describes a 6-year-old girl with a known history of musculoskeletal vascular anomalies who presented with recurrent abdominal pain and rectal bleeding after seemingly minor trauma. A diagnosis of enteric vascular malformation was established, and the patient was treated by a combined laparoscopic and open approach. This case highlights the fact that in the child with known vascular anomalies who presents with sudden gastrointestinal bleeding and intestinal obstruction, the diagnosis of gastrointestinal vascular anomaly should be suspected, and exploratory laparoscopy should be considered. The current management of enteric vascular anomalies is reviewed, and the differences between vascular malformations and hemangiomas are analyzed.

Mesenteric inflammatory pseudotumor as a cause of abdominal pain in a teenager: presentation and literature review.

Inflammatory pseudotumor (IP) is an unusual cause of chronic abdominal pain in children. The management of these lesions is complicated by controversies surrounding their appropriate classification and the numerous alternate names with which they are described. Successful treatment requires careful radiologic and pathologic evaluation to distinguish IPs from other lesions, along with complete surgical resection. We present the case of a 15-year-old boy with IP and review the literature in an attempt to simplify the description of these tumors.

Imaging evaluation of pediatric mediastinal masses.

Mediastinal masses in children are a heterogeneous group of asymptomatic to potentially life-threatening congenital, infectious, or neoplastic lesions that can present complex diagnostic and therapeutic dilemmas. This article presents the imaging features of the common mediastinal masses seen in the pediatric population. Classification of the masses is performed according to the traditional mediastinal compartment model, consisting of the anterior, middle, and posterior mediastinum. This scheme facilitates differentiation of the variety of disorders.

Contrast extravasation predicts the need for operative intervention in children with blunt splenic trauma.

BACKGROUND: Although the presence of a contrast blush (CB) on computed tomographic (CT) scan is associated with an increased failure rate of nonoperative management in adults with blunt splenic injury, little information is available for the pediatric population, where nonoperative management is the standard of care. Our aim was to determine whether the finding of CB on CT scan could predict failure of nonoperative therapy in children with blunt splenic injury. METHODS: A retrospective analysis of 343 patients admitted with blunt splenic injury to our Level I pediatric trauma center over a 7-year period was performed. All CT scans were reviewed by a radiologist who was blinded to the patient outcome. We excluded 127 patients who either underwent immediate laparotomy without a CT scan or whose CT scans were unavailable at the time of this review. We divided the patients into two groups on the basis of the presence or absence of CB on the updated reading of the CT scan. Demographic variables analyzed included age, sex, mechanism of injury, Injury Severity Score, Glasgow Coma Scale score, initial hemoglobin and hematocrit, and emergency department pulse rate and systolic blood pressure. Outcome measures compared include length of stay, length of intensive care unit stay, the need for splenic intervention, and mortality. Continuous variables were compared using Student's t test for normally distributed data and the Mann-Whitney test for skewed data. Categorical data were compared using chi2 analysis or Fisher's exact test. Statistical significance was assigned to values of p < 0.05. RESULTS: Among the study population (N = 216), 27 patients (12.5%) had CB on CT scan. Patients with CB had significantly lower hematocrit (p = 0.0004) and required operative intervention more frequently than those without CB (22% vs. 4%;p = 0.0008). Among patients with CB, mean pulse rate at presentation was higher in those that required splenic intervention (SI) (129 +/- 20.1) compared with those who underwent successful nonoperative therapy (100.4 +/- 23.1; p = 0.01). Only grade V injuries correlated with the need for laparotomy. CONCLUSION: Children with blunt splenic injury who have CB on CT scan are more likely to require SI than those without CB. However, because the majority of patients with CB did not require SI, in the absence of hemodynamic instability, this finding may be insufficient to determine the need for SI. CB is a specific marker of active bleeding that may predict the need for early splenic intervention in a specific subset of patients at presentation.

Predictors of outcome for children with perforated appendicitis initially treated with non-operative management.

BACKGROUND: Initial non-operative therapy for children with perforated appendicitis has become increasingly popular with the advent of powerful broad-spectrum antibiotics. However, there is no consensus regarding which patients may be managed effectively with this strategy. We reviewed all children with perforated appendicitis who were treated initially with non-operative therapy to determine those characteristics that may predict a successful outcome. METHODS: We reviewed the medical records of children admitted to our hospital between January 1, 2000 and May 1, 2003 with the diagnosis of perforated appendicitis. Only those who were treated initially with a single broad-spectrum antibiotic (piperacillin-tazobactam), with the intention of performing an interval appendectomy, were included in this study. Patients were divided into two groups based on whether they were managed successfully with non-operative therapy: Responders and non-responders. Non-responders were defined as patients who either did not improve with antibiotic therapy or who required appendectomy prior to their electively scheduled time (six weeks). Demographic data, duration and type of presenting symptoms, initial white blood cell count (WBC), percent bands, percent neutrophils (PMNs), computed tomography (CT) interpretation, and interventions/operations were abstracted. Categorical data were compared using Chi-square analysis or the Fisher exact test; continuous variables were compared using the Student t-test and the Mann-Whitney U-test. RESULTS: Overall, 26% (19/73) of patients treated initially non-operatively required appendectomy prior to the electively scheduled date. There was no difference between responders (n = 54) and non-responders (n = 19) with respect to age, gender, initial WBC, percent bands, percent PMNs, or duration and type of presenting symptoms. However, responders were more likely to have a phlegmon on CT scan compared to non-responders (11/54 vs. 0/19, p = 0.03). Non-responders were twice as likely to undergo drainage of an abscess by interventional radiology (10/19 vs. 13/54, p = 0.02) compared to responders. Among all patients who required percutaneous drainage, the failure rate of non-operative management was 43% (10/23). CONCLUSIONS: Children with perforated appendicitis can be managed effectively with nonoperative therapy, even in the presence of intra-abdominal abscesses. However, the need for abscess drainage increases the failure rate, perhaps due to inadequate source control. Those patients with a phlegmon on CT scan as opposed to an abscess, are most likely to respond to non-operative management. Initial non-operative therapy of perforated appendicitis in children is appropriate under certain clinical circumstances, especially when the body itself or interventional radiology can achieve adequate source control.

Pancreatic ascites in an infant: lack of symptoms and normal amylase.

A 4-month-old boy presented with 9 days of abdominal distension. The abdomen was tense, distended, and nontender, with a fluid wave. Hypoalbuminemia, hyponatremia, high lipase, normal amylase, high ascitic fluid: lipase, amylase, and serum-ascites albumin gradient < 1.1 were present. Abdominal CT showed large ascites, edema, and pancreatic cyst. No improvement was noted with bowel rest, TPN, albumin, furosemide, octreotide, and paracentesis. Endoscopic retrograde cholangiopancreatography showed disrupted pancreatic duct and a cyst. Pancreatic duct stenting was complicated by early outward migration of the stent and was thus ineffective. An exploratory laporatomy revealed a cyst. Cystogastrostomy resolved the pancreatitis and ascites. The patient was discharged off TPN and tolerating enteral nutrition. Pancreatic ascites is rare, producing few or no symptoms in infants. In conclusion, our patient may have had viral pancreatitis, complicated by a disrupted duct and/or ruptured pseudocyst with ascites formation. Medical management was ineffective. Surgery appears to have been curative.

Aerosol drug delivery using heliox and nebulizer reservoirs: results from an MRI-based pediatric model.

An MRI-based model of the mouth, throat, and upper airways of a 5-year-old boy is used to evaluate methods for increasing the nebulized drug dose delivered to the lungs. Four methods are considered: (1) standard nebulizer delivery with air, (2) delivery with 70/30 helium-oxygen (heliox), (3) delivery with air and an aerosol-conserving reservoir, and (4) delivery with heliox and a reservoir. When comparing air and heliox, delivery flowrates were adjusted so that the aerosols produced were of similar size. The reservoir utilized was the Medicator Aerosol Maximizer (Healthline Medical, Baldwin Park, CA). It conserves the aerosol generated by the nebulizer during exhalation and makes it available for the next inhalation. Technetium-DTPA was utilized. The standard nebulizer driven by air delivered 2.2% of the dose loaded into the nebulizer to the lungs as fine droplets, versus 3.3% for the nebulizer with heliox (50% increase; p = 0.002 vs. air), 2.9% for the nebulizer plus reservoir driven by air (32% increase; p = 0.02 vs. no reservoir), and 4.0% for the nebulizer plus reservoir driven by heliox (82% increase; p = 0.002 vs. air without reservoir). The increased pulmonary dose when heliox was utilized occurred because of decreased deposition within the nebulizer and other delivery equipment. The increased pulmonary dose when the reservoirs were utilized occurred due to a decrease in the dose expelled from the nebulizer by exhalation.

Steroid-resistant nephrotic syndrome and congenital anomalies of kidneys: evidence of locus on chromosome 13q.

BACKGROUND: Steroid-resistant nephrotic syndrome (SRNS) and congenital anomalies of kidney and urinary tract (CAKUT) are major causes of renal dysfunction in children. Although a few patients with 13q deletion have been previously reported with renal anomalies, the association of SRNS with 13q has not been reported and critical regions associated with CAKUT have not been identified. We present the results of deletion mapping studies to identify the critical regions. METHODS: Cytogenetic and deletion mapping studies were performed on DNA obtained from peripheral blood of two children with renal anomalies and interstitial deletion of 13q as well as their parents. Twenty eight microsatellite markers with a spacing of 1-8 Mb (1-3 cM) were utilized. RESULTS: The patients (both males, 5 and 10 years old) had varying severity of developmental delay and other neurologic disorders. The renal involvement included hydronephrosis, ureterocele, renal dysplasia, and mesangioproliferative SRNS. Our studies imply existence of at least two critical regions in the 13q area that are linked to CAKUT. The first is a 7 Mb region defined by markers D13S776 and D13S891 shared by both patients. The second is a much larger region extending at least 33 Mb above D13S776 seen in one patient with severe renal malformations and SRNS. CONCLUSION: We report an association of chromosome 13q with CAKUT as well as SRNS. Our studies suggest the presence of more than one gene in this region that is likely to be involved in renal development and function.

Utility of radiographic hepatic injury grade in predicting outcome for children after blunt abdominal trauma.

BACKGROUND/PURPOSE: The American Association for the Surgery of Trauma (AAST) liver injury grading system has been adopted in the management of pediatric hepatic injuries. However, the usefulness of this grading system in children remains undefined. The authors, therefore, examined the validity of AAST grading in the management of pediatric blunt liver injury. METHODS: The authors identified 152 patients, ages 0 to 18 years, with blunt hepatic injury treated at our pediatric trauma center between 1995 and 2000. Radiographic AAST grade was assigned retrospectively by 2 radiologists. Variables analyzed included age, gender, Glasgow Coma Score (GCS), Injury Severity Score (ISS), and associated injuries. Outcome measures were mortality rate and length of stay (LOS). Statistical analysis was performed using analysis of variance or linear regression. RESULTS: Computed tomography (CT) scans were available for 95 patients. Radiographic injury grade did not correlate with mortality rate, hospital LOS or intensive care unit (ICU) LOS. ISS and associated injury, but not age, gender, or GCS, were predictive of LOS. Grade did not correlate with mortality rate, ICU LOS, or hospital LOS. CONCLUSIONS: Radiographic liver grading does not predict outcome reliably in children and should not be the main parameter utilized to guide clinical decision making. A role for scoring systems that utilize factors such as associated injuries and ISS is indicated.