A Retrospective Study of 248 Pediatric Oral Sedations Utilizing the Combination of Meperidine and Hydroxyzine for Dental Treatment.

UNLABELLED: Oral sedation for pre-cooperative and anxious pediatric patients is an important tool for the pediatric dentist. Few studies have examined the sedation regimen of meperidine and hydroxyzine. OBJECTIVES: The primary goal of this study was to evaluate the overall safety and effectiveness of the meperidine/hydroxyzine drug combination. Secondary goals included detecting potential factors that alter sedation effectiveness. STUDY DESIGN: Two hundred and forty eight electronic health records of pediatric patients (131 females, 117 males) who received meperidine/hydroxyzine sedations in a university setting were evaluated. Pediatric dental residents rated each case according to the Frankl behavioral scale and for effectiveness. Numerous factors were analyzed to evaluate their significance on overall effectiveness. Factors examined included age at time of treatment, gender, ASA status, Frankl score at various points during treatment, sextant of treatment, operator experience, dosage, use of nitrous oxide, and any complications encountered during treatment, both major and minor. RESULTS: Over 81% of sedations were considered effective or very effective. Statistically significant findings included age of patient, pre-sedation behavior, and willingness to take the medication. Less than 5% of sedations were aborted due to behavior. Only one major complication was found, which was not related to the sedation. CONCLUSIONS: Meperidine combined with hydroxyzine is a safe and effective sedation regimen for uncooperative or pre-cooperative children during dental treatment.

Proteomic and phenotypic analysis of triclosan tolerant verocytotoxigenic Escherichia coli O157:H19.

Triclosan is a biocidal active agent commonly used in domestic and industrial formulations. Currently, there is limited understanding of the mechanisms involved in triclosan tolerance in Escherichia coli O157. The aim of this study was to identify the differences between a triclosan susceptible E. coli O157:H19 isolate (minimum inhibitory concentration; MIC 6.25 µg/ml) and its triclosan tolerant mutant (MIC>8000 µg/ml) at a proteomic and phenotypic level. Two dimensional DIGE was used to identify differences in protein expression between the reference strain and triclosan tolerant mutant in the presence and absence of triclosan. DIGE analysis indicates the proteome of the reference E. coli O157:H19 was significantly different to its triclosan tolerant mutant. Significant changes in protein expression levels in the triclosan tolerant mutant included the known triclosan target FabI which encodes enoyl reductase, outer membrane proteins and the filament structural protein of flagella, FliC. Phenotypic studies showed that the triclosan tolerant mutant MIC decreased in the presence of efflux inhibitor phenyl-arginine-ß-naphthylamide and biofilm formation was increased in the mutant strain. The data generated indicates that enhanced triclosan tolerance is a result of multiple mechanisms which act together to achieve high-level resistance, rather than mutation of FabI alone.

The effect of bovine diet on Salmonella survival in synthetic abomasal fluid.

AIMS: To investigate the effect of diet on the survival of Salmonella in the bovine abomasum. METHODS AND RESULTS: Five fistulated cows were randomly assigned to one of five diets denoted as: (i) 100% grass, (ii) grass + 5·3 kg DM concentrate, (iii) 100% grass silage, (iv) 100% hay and (v) maize/grass silage plus concentrates. Rumen fluid was harvested from each dietary treatment and inoculated with nonacid (NA) and acid-adapted (AA) 5-strain Salmonella cocktails. After 24-h incubation period, Salmonella were acid challenged to synthetic abomasum fluid (SAF, pH 2·5) for 5 h to determine their resistance to low pH. The study found that the volatile fatty acids composition and the pH profile of bovine rumen fluid were significantly altered (P <0·05) by some of the dietary treatments but not others. Regression analysis found that significantly higher numbers of acid-adapted Salmonella survived in SAF after incubation in rumen fluid from diets 1, 2 and 4, but fewer significant differences were found between diets for nonacid-adapted Salmonella. The results suggest that the acid-adapted cells were subjected to a higher level of cell injury than the nonadapted cells. CONCLUSIONS: Pre-incubation in rumen fluid did influence the resistance of nonacid and acid-adapted Salmonella to SAF but it was dependant on the dietary treatment fed to the cows. SIGNIFICANCE AND IMPACT OF THE STUDY: This study examined the use of diet, as a modulating factor to limit the bovine excretion of Salmonella with a view to providing a scientific basis for the design of dietary management controls in the future.

Molecular characterization of Irish E. coli O157:H7 isolates of human, bovine, ovine and porcine origin.

AIMS: To determine the degree of relatedness between isolates of Escherichia coli O157:H7 of human, bovine, ovine and porcine origin. METHODS AND RESULTS: Escherichia coli O157:H7 isolates were compared using (i) PFGE XbaI patterns, (ii) PCR profiles of virulence genes and (iii) the DNA sequences of genes reported to play a role in pathogenicity. The 77 E. coli O157:H7 isolates demonstrated 49 different PFGE patterns of which, eight were common to multiple isolates, and the remaining 41 were distinct. Isolates of different origin did not correlate, except for one cluster consisting of two human and two beef isolates. The majority of animal isolates had the same PCR profiles of virulence genes as those isolated from clinical patients. Single nucleotide polymorphisms (SNPs) were identified in the sequence of a 255-bp region of the vtx2 subunit A gene. CONCLUSIONS: Six SNPs were detected in the vtx2A gene, defining four different haplotypes. One nonsynonymous substitution encoded for an amino acid change from glutamic to aspartic acid. SIGNIFICANCE AND IMPACT OF THE STUDY: Results indicate that although E. coli O157:H7 isolates of differing origin were distinct by PFGE, the DNA sequences of the main virulence genes associated with human clinical illness were conserved.

The potential use of chilling to control the growth of Enterobacteriaceae on porcine carcasses and the incidence of E. coli O157:H7 in pigs.

AIMS: To (i) monitor the presence of Enterobacteriaceae as indicators of faecal contamination on pig carcasses, (ii) examine the potential use of chilling as a critical control point (CCP) and establish its influence on pig carcass categorization by Decision 471/EC and (iii) determine the incidence of E. coli O157:H7 in pigs. METHODS AND RESULTS: Porcine faecal samples and carcass swabs were collected before and after chilling at four Irish pig abattoirs and examined for Enterobacteriaceae and E. coli O157:H7. Chilling generally reduced Enterobacteriaceae counts on carcasses, but increases were also observed, particularly in one abattoir. E. coli O157:H7 was absent from carcasses before chilling, present on 0.21% after chilling and was recovered from 0.63% of faecal samples. All of the isolates were found to contain virulence genes associated with clinical illness in humans. CONCLUSIONS: The data show that overall chilling had the capacity to reduce the numbers of carcasses positive for the presence of Enterobacteriaceae. SIGNIFICANCE AND IMPACT OF STUDY: The influence of chilling on the categorization of pig carcasses suggests that it has the potential to improve the numbers of acceptable carcasses and the process could be used as a CCP within a HACCP plan.

Prevalence and molecular characterization of Escherichia coli O157:H7 on Irish lamb carcasses, fleece and in faeces samples.

AIMS: To determine the prevalence, seasonal variation and virulence characteristics of Escherichia coli O157:H7 in lambs presented for slaughter in Ireland. METHODS AND RESULTS: Over a 13-month period, pre- and postchill carcass swabs, faeces and fleece samples from 1600 lambs were examined for the presence of E. coli O157:H7. Escherichia coli O157:H7 was isolated from 5.75% (23/400) of fleece samples, 1.5% (6/400) of pre- and 1% (4/400) of postchill carcass swabs but was not isolated in faeces (0/400). The present study detected no evidence of seasonal variation. Polymerase chain reaction analysis showed that both the vt1 and vt2 genes associated with clinical illness were carried by five of the E. coli O157:H7 isolates, while 24 of the remaining isolates carried the vt2 gene only. Phage typing detected four different subtypes: PT 32 (48.48%), PT 8 (12.12%), PT 31 (12.12%) and PT 21/28 (12.12%). CONCLUSIONS: Escherichia coli O157:H7 is present in lambs at slaughter in Irish abattoirs and the virulence profiles of these isolates reveals that they are potentially harmful to humans. SIGNIFICANCE AND IMPACT OF THE STUDY: The present study provides crucial information indicating that sheep may be a significant contributing source to human E. coli O157:H7 infection.

Assessing the hygiene of pig carcasses using whole-body carcass swabs compared with the four-site method in EC Decision 471.

An investigation was carried out in a pig abattoir to determine the microbiological status of carcasses being produced after slaughter and dressing. The carcasses were sampled in accordance with EC Decision 471 in relation to the application of hazard analysis critical control point (HACCP) criteria to the slaughter of animals. In this regard, four sites on the animals were examined on five consecutive carcasses during each of 10 visits for the presence of total viable counts and Enterobacteriaceae. A comparison of the EC four-site method, with a whole-body swab technique, as a means of measuring carcass contamination found that the two methods gave significantly different results for both groups of organisms. A comparison of the mean of the individual data from the four sites with the data from the pooled samples revealed that there was a poor relationship between the two. Samples may be taken by excision or swabbing and allocated to three categories of process control, which, in turn, are based on microbiological criteria that are different, depending on whether sampling is by excision or swabbing. The influence of these changes in microbiological criteria is discussed in relation to the categorization of samples as acceptable, marginal, or unacceptable and the influence this has on process control. Finally, the proposed introduction of Salmonella as a safety indicator in the EC HACCP system is discussed.

Induction of c-myc mediated apoptosis in SV40-transformed rat fibroblasts.

The ability of SV40 T antigen to block apoptosis was investigated in Rat1-A fibroblasts expressing an estrogen-dependent c-myc construct, mycER (Eilers et al., 1989). These RatmycER cells undergo apoptosis upon activation of c-myc by estradiol under conditions of serum deprivation. Under such conditions SV40-transfected derivatives of RatmycER undergo apoptosis as evidenced by rapid cell death, characteristic morphological changes and DNA fragmentation in a manner indistinguishable from the parental cell line, indicating that T antigen is not able to protect against myc-induced apoptosis. In as much as it had been reported that myc-mediated apoptosis involves wild-type p53 in other systems and T antigen is known to bind and inhibit p53 function, we examined these two polypeptides under different experimental conditions. In all cases, the great majority of the p53 in the SV40 transfectants was found to be in complexes with T antigen. Furthermore, the residual p53 in the uncomplexed state was not sufficient to transactivate an endogenous promoter, WAF1/p21. These data indicate that the failure of T antigen to block apoptosis cannot be attributed to defective function of T antigen and suggest that myc-mediated apoptosis may involve a p53-independent pathway in these cells.

SV40-mediated immortalization of human fibroblasts.

We have identified a multistep mechanism by which the DNA virus SV40 overcomes cellular senescence. Expression of SV40 T antigen is required for both transient extension of life span and unlimited life span or immortalization. These effects are mediated through inactivation of function of growth suppressors pRB and p53 via complex formation with T antigen. However, immortalization additionally requires inactivation of a novel growth suppressor gene, which has recently been identified to be on the distal portion of the long arm of chromosome 6, designated SEN6. We propose that SEN6 is responsible for cellular senescence in fibroblasts and other cells.

Identification of herpes simplex virus infection by immunoperoxidase and in situ hybridization methods.

Seven cases of visceral herpes simplex virus (HSV) infection were observed in five cases of hematopoietic disease and in one case each of a newborn baby and a pregnant woman. These seven cases were studied with an immunoperoxidase method and in situ hybridization. In HSV lesions of squamous epithelium, the immunoperoxidase method using rabbit anti-human HSV revealed positive staining, mainly in the nucleus but with some cytoplasmic staining. DNA in situ hybridization revealed stronger positive staining in the nucleus. In HSV hepatitis positive staining was seen in the nucleus and cytoplasm, both by immunoperoxidase and in situ hybridization methods. In the newborn baby, HSV lesions were observed in the brain only, with numerous positive astrocytes identified by the immunoperoxidase method and a few positive astrocyte nuclei by in situ hybridization. Cultured human fetal fibroblasts from the lung were infected with HSV. The immunoperoxidase method revealed diffuse positive staining in the nucleus and in the cytoplasm whereas in situ hybridization revealed fibrillar positive staining in the nucleus only. Thus, the immunoperoxidase method using rabbit anti-human HSV can detect the presence of HSV protein more sensitively than in situ hybridization, probably because of the greater quantity of HSV protein compared with HSV DNA in infected cells.

Identification of cytomegalovirus infection in acquired immunodeficiency syndrome.

Cytomegalovirus (CMV) infection was observed in 10 of 12 autopsy cases of acquired immunodeficiency syndrome (AIDS) and appears to be the commonest life-threatening viral infection in AIDS. In all 10 cases, adrenal glands were affected with CMV and adrenal medullary necrosis was present in 6 cases. Lungs were affected with CMV in 7 cases with disseminated infection and positive CMV culture. In situ hybridization of tissue sections with CMV-specific DNA provided positive staining for CMV in inclusions as well as other infected cells without obvious inclusions. Human diploid lung fibroblasts were infected with isolated CMV in culture, yielding positive CMV identification within 5 days by in situ hybridization before specific cytopathic changes appeared in the fibroblasts. The early and specific detection of CMV is possible by in situ hybridization with cultured fibroblasts.

Role of antiviral antibodies in resistance against coxsackievirus B3 infection: interaction between preexisting antibodies and an interferon inducer.

An experimental model of coxsackievirus B3 infection in newborn mice was utilized to examine the protective role of antiviral antibodies and an interferon inducer, polyinosinic acid-polycytidylic acid [poly(I:C)]. Subcutaneous administration to the infected mice of specific antiviral antibodies resulted in significant protection against coxsackievirus B3 infection. Antibody-treated animals had shortened viremia, early clearance of virus from tissues, and a reduced mortality rate. Dose response to antibodies was clearly demonstrated. However, the time of antibody administration in relation to the infection cycle was important. The protection was observed if antibodies were given before infection (24 h) or shortly after (2 h) infection. Administration of antibodies 24 h after infection resulted in no protection. The interferon inducer poly(I:C) prolonged the survival time of the infected mice, but this protective effect was incomplete and could only be demonstrated in animals treated before infection (24 h) or shortly after (2 h) infection. Enhanced protection against lethal coxsackievirus B3 infection was achieved in animals treated with a combination of antiviral antibodies and poly(I:C). These data confirm that antibody-mediated immunity plays a significant role in resistance against coxsackievirus B3 infection and suggest that antiviral antibodies may interact with poly(I:C) or work independently to produce an enhanced protective effect.

Pulmonary involvement with cytomegalovirus infections in children.

Among 40 hospitalized infants and children with cytomegalovirus infection, 14 (35%) had interstitial pneumonitis, 4 (10%) had wheezing or tachypnoea but without x-ray evidence of classical interstitial pneumonia, the remaining 22 (55%) were free of pulmonary involvement. Most patients had tachypnoea and nonproductive cough of varying durations: those with underlying pulmonary pathology tended to have persistent and prolonged respiratory symptoms. Mortality and severity of the lung disease were related to the underlying immunodeficiency or concomitant pulmonary process.