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Biomedical subjects

C B Hall

Publications and source records attributed to C B Hall.

At least 37 records · Page 2Linked to original sources
PubMed1999

Predicting deterioration in previously healthy infants hospitalized with respiratory syncytial virus infection.

OBJECTIVE: To estimate the incidence of clinical deterioration leading to intensive care unit transfer in previously healthy infants with respiratory syncytial virus (RSV) infection hospitalized on a general pediatric unit and, to assess the hypothesis that history, physical examination, oximetry, and chest radiographic findings at time of presentation can accurately identify these infants. STUDY DESIGN: A virology database was used to identify and determine the disposition of all children </=1 year of age admitted to the Children's Hospital at Strong (CHaS) with RSV infection during the 1985 to 1994 respiratory seasons. Index patients were all previously healthy, full-term infants admitted initially to the general inpatient services at CHaS or Rochester General Hospital, a second University of Rochester teaching hospital, whose clinical deterioration led to transfer to the pediatric intensive care unit (PICU). These infants were matched retrospectively (for year and date of infection, sex, chronologic age, and race) with two hospitalized controls who did not require PICU transfer. Chest radiographic findings, respiratory rate (RR), O(2) saturation, and presence of wheezing at time of presentation to the emergency department (ED) were compared. RESULTS: During the study years, 542 previously healthy, full-term infants were admitted to the general pediatric unit at CHaS with proven RSV infection. Ten (1.8%; 95% confidence interval, 0.9%, 3.4%) were transferred subsequently to the PICU, primarily for close monitoring of progressive respiratory distress. Data for these patients and 7 patients transferred from Rochester General Hospital to the PICU at the CHaS were compared with those for control patients. The mean RR in the ED (63 vs 50), and O(2) saturation in the ED (88% vs 93%) were modestly abnormal in cases compared with controls. Wheezing on examination at time of presentation and chest radiographic findings did not differ between the two groups. A RR >80 and an O(2) saturation <85% at time of presentation each had a specificity >97% for predicting subsequent deterioration. Each parameter, however, had a sensitivity </=30%. CONCLUSION: Clinical deterioration requiring PICU admission is an uncommon occurrence in previously healthy infants admitted to a general pediatric inpatient unit with RSV infection. Extreme tachypnea and hypoxemia were both associated with subsequent deterioration; however, only a small proportion of patients who clinically deteriorated presented in this way. The clinical usefulness of these parameters, therefore, is limited. respiratory syncytial virus, deterioration, healthy infants, prediction.

Case-Control Studies↗
PubMed1999

Respiratory syncytial virus: A continuing culprit and conundrum.

For more than 4 decades, respiratory syncytial virus (RSV) has been recognized as a worldwide pathogen of import. In the United States alone, approximately 91,000 infants are hospitalized with RSV infections yearly, at an estimated annual cost of at least 300 million dollars. The burden of RSV infections is even greater if outpatient visits for children and adults and RSV morbidity in patients with underlying conditions are included. Obstacles to controlling RSV remain appreciable and challenging. The virus causes predictable, widespread outbreaks of illness each year and repeated infections throughout life. The most severe infections occur in the youngest infants, especially premature infants and those with bronchopulmonary dysplasia. Patients with chronic pulmonary and cardiac diseases and those with immunosuppression also are at high risk for severe RSV infection, and their risk may last well beyond infancy. Institutionalized adults, especially the elderly, also are at risk of complicated disease. To be effective, a vaccine against RSV must be administered shortly after birth and ideally should provide better immunity than natural disease, if reinfection is to be prevented. It must also be effective in the wide variety of populations at risk. Recently, several candidate vaccines for RSV have been developed. In the interim, RSV immune globulin and a monoclonal antibody to RSV have been approved for prophylaxis in infants at high risk. For therapy in immunocompromised patients, especially patients receiving transplants, a combination of RSV immune globulin and the antiviral ribavirin has been tried. Therapy for RSV, however, remains limited, controversial, and mostly supportive.

Bronchiolitis↗
PubMed1998

Primary human herpesvirus 7 infection: a comparison of human herpesvirus 7 and human herpesvirus 6 infections in children.

OBJECTIVE: To define the clinical and virologic characteristics of primary human herpesvirus 7 (HHV-7) infection and to compare these characteristics with those of primary human herpesvirus 6 (HHV-6) infection. STUDY DESIGN: A prospective convenience sample study of 496 children < or =3 years old. HHV-7 and HHV-6 infections were identified by viral isolation. Polymerase chain reaction and serology for HHV-7 and HHV-6 were performed. Clinical and laboratory characteristics of patients were obtained from medical records and follow-up interviews. RESULTS: Children with primary HHV-7 infection (n = 8) were identified and compared with children with primary HHV-6 infection (n = 29) detected during the same time period. All children were febrile (mean temperature 39.8 degrees C) with no difference in the degree of fever, frequency of rash, or gastrointestinal complications between the groups. The median age of children with primary HHV-7 infection was 26 months, significantly older than that of children with primary HHV-6 infection (median, 9 months). Children with primary HHV-7 infection were also more likely than those with primary HHV-6 infection to have seizures associated with the illness (P = .004). CONCLUSION: Primary infection with HHV-7 can cause a highly febrile illness in childhood, complicated by seizures. The serologic diagnosis of primary HHV-6 and HHV-7 infections may be confounded by cross-reacting antibodies.

Age Factors↗
PubMed1998

Constraints on general slowing: a meta-analysis using hierarchical linear models with random coefficients.

General slowing (GS) theories are often tested by meta-analysis that model mean latencies of older adults as a function of mean latencies of younger adults. Ordinary least squares (OLS) regression is inappropriate for this purpose because it fails to account for the nested structure of multitask response time (RT) data. Hierarchical linear models (HLM) are an alternative method for analyzing such data. OLS analysis of data from 21 studies that used iterative cognitive tasks supported GS; however, HLM analysis demonstrated significant variance in slowing across experimental tasks and a process-specific effect by showing less slowing for memory scanning than for visual-search and mental-rotation tasks. The authors conclude that HLM is more suitable than OLS methods for meta-analyses of RT data and for testing GS theories.

Aged↗
PubMed1998

Persistence of human herpesvirus 6 according to site and variant: possible greater neurotropism of variant A.

Little is known of the persistence and pathogenicity of human herpesvirus 6 (HHV-6) after primary infection, including the role of strain variant. Over 2 to 5 years, 2,716 children and 149 families were studied. Peripheral blood mononuclear cell (PBMC), saliva, and cerebrospinal fluid (CSF) specimens were examined for HHV-6 DNA and variant. Ninety-nine percent of isolates causing primary infection were HHV-6 variant B (HHV-6B), which predominated in 95%-98% of the variants persisting in PBMC and saliva specimens from children and adults. Of 668 CSF samples, 13% contained HHV-6 DNA; of 77 children examined after primary infection, 61% had HHV-6 DNA detected only in their CSF and 39% had HHV-6 DNA in both CSF and PBMCs. HHV-6 variant A (HHV-6A) was detected significantly (P = .0001) more frequently in CSF than in PBMCs or saliva. In children for whom HHV-6 was identified in both CSF and PBMCs, PBMCs contained only HHV-6B, while CSF contained HHV-6A or HHV-6B, not both. Thus, in patients with dual infection, only HHV-6A persisted in CSF, which suggests that HHV-6A has greater neurotropism. Findings for adults indicate that dual infection occurs; variant persistence is similar to that for children. The frequency of HHV-6A infection increased little with age, thereby indicating that HHV-6A infection remains uncommon into adulthood. This study suggests that HHV-6 variants have different immunobiologic courses and neurotropism.

Adult↗
PubMed1998

A practitioner's guide to human herpesvirus-6 (HHV-6) and human herpesvirus-7 (HHV-7).

Human herpesvirus-6 (HHV-6) and HHV-7 are newly recognized ubiquitous human viruses first discovered in patients with AIDS or lymphoproliferative disorders. Much more information is available about the clinical characteristics of infection with HHV-6 than HHV-7. Primary infection with HHV-6 occurs in early childhood and is most commonly manifested as an undifferentiated highly febrile illness, with seizures noted to be the most common complication. A subset of children develop the classic manifestations of roseola infantum or exanthem subitum. Other neurologic diseases in adults such as encephalitis and multiple sclerosis also have been linked to HHV-6; however, the role of HHV-6 in these clinical entities has not been fully elucidated. Although HHV-6 and HIV are both tropic for CD4+ lymphocytes and interact in vitro, there is no evidence at present that HHV-6 plays a role in HIV disease. HHV-7 is similar to HHV-6 in genetic organization and structure. Little is known of the clinical characteristics of infection with HHV-7 or its ability to cause disease in children or reactivation in adults.

AIDS-Related Opportunistic Infections↗
PubMed1998

Risk of recurrent seizures after a primary human herpesvirus 6-induced febrile seizure.

OBJECTIVE: To test the hypothesis that children experiencing first febrile seizures caused by human herpesvirus 6 (HHV-6) have an increased risk for recurrent seizures when compared with children experiencing first febrile seizures attributed to other illnesses. DESIGN AND PARTICIPANTS: Descriptive prospective study of 36 HHV-6 culture-positive children and a matched subgroup of 86 HHV-6 culture-negative children, all of whom had their first febrile seizures evaluated in a tertiary care emergency department and were followed for at least 12 months, with an average follow-up of 35.7 months. PRIMARY OUTCOME MEASURE: The recurrence of seizures among HHV-6 culture-positive and HHV-6 culture-negative children with no known previous neurologic deficits. RESULTS: A decreased incidence of recurrent seizures occurred in children whose first febrile seizures were caused by HHV-6. Twenty percent of HHV-6 culture-positive children and 40% of HHV-6 culture-negative children (P < 0.038) experienced a recurrent seizure within 1 year of their first febrile seizure. The mean time to recurrence within 12 months was 8.6 months for children with HHV-6 infection and 3.8 months (P < 0.001) for children without HHV-6 infection. Most recurrent seizures occurred within 12 months of a first febrile seizure for both HHV-6-positive and HHV-6-negative children (88 and 91%). CONCLUSIONS: Children who had their first febrile seizures caused by primary HHV-6 infection did not demonstrate an increased risk for recurrent seizures when compared with children whose first febrile seizures were from other etiologies.

Child, Preschool↗
PubMed1998

Risk factors for the early acquisition of human herpesvirus 6 and human herpesvirus 7 infections in children.

OBJECTIVE: Human herpesviruses 6 and 7 (HHV-6 and HHV-7) are common infections in children, but risk factors for their early acquisition have not been described. METHODS: Excess sera from children 12 to 31 months of age enrolled in a cross-sectional, random survey were tested for human herpesviruses 6 and 7 infection, as measured by using immuno-blot and immunofluorescence assays. RESULTS: Of 164 children 131 (80%) had antibody to HHV-6, and 79 (47%) of 167 had antibody to HHV-7. In logistic regression analysis low income [odds ratio (OR), 2.9; 95% confidence intervals (CI), 1.02 to 8.7] and having more than 1 sibling (OR=2.1, 95% CI=0.9 to 5.1) were risk factors for HHV-6 infection after adjusting for age, whereas month of test (OR=2.7, 95% CI=1.3 to 5.9) and Black race (OR=2.0, 95% CI=0.9, 4.6) were associated with a higher prevalence of HHV-7 infection. In contrast having ever been breast-fed appeared to protect against HHV-7 infection (OR=0.5, 95% CI=0.3 to 1.1). CONCLUSIONS: Despite studies linking both HHV-6 and HHV-7 with exanthem subitum, risk factors for the early acquisition of HHV-6 and HHV-7 are distinct. Subsequent studies investigating the transmission of HHV-6 should explore family size and other factors associated with poverty, whereas breast-feeding should be examined as a protective factor for HHV-7 infection.

Antibodies, Viral↗
PubMed1998

Circulation patterns of genetically distinct group A and B strains of human respiratory syncytial virus in a community.

Human respiratory syncytial virus (HRSV) is classified into two major groups, A and B, each of which contains multiple variants. To characterize the molecular epidemiology of HRSV strains over time, sequencing studies of a variable region of the attachment protein gene from a single community in the United States during 5 successive years were performed. Phylogenetic analysis revealed distinct clades (genotypes) that were further classified in subtypes based on > or = 96% nucleotide similarity. Five genotypes and 22 subtypes among 123 group A HRSV isolates, and four distinct genotypes and six subtypes among 81 group B HRSV isolates were identified. One to two genotypes or subtypes accounted for > or = 50% of isolates from a given year. A shift in the predominant genotype or subtype occurred each year such that no genotype or subtype predominated for more than 1 of the 5 study years. The consistency in the displacement of the predominant strain suggests that a shift, even within the same group, is advantageous to the virus. It was hypothesized that the 'novel' strain is better able to evade previously induced immunity in the population and consequently either circulates more efficiently or is more pathogenic. The yearly shift in HRSV strains may contribute to the ability of HRSV to consistently cause yearly outbreaks of HRSV disease. These results also suggest that isolates may need to be characterized as to both group and genotype to fully understand protective immunity after natural infection and efficacy studies of candidate vaccines.

Amino Acid Sequence↗
PubMed1997

Severity of respiratory syncytial virus infection is related to virus strain.

The relationship between respiratory syncytial virus (RSV) strain and disease severity was assessed in 265 hospitalized infants over a 3-year period (1988-1991). A severity index of clinical and physiologic parameters was used to grade illness severity. Multivariate analysis of 134 infants infected with group A RSV strains and 131 infants infected with group B strains indicated that prematurity, underlying medical conditions, group A RSV infection, and age < or =3 months were independently associated with severe disease. Odds ratios for severe disease for these risk factors were 1.83, 2.84, 3.26, and 4.39, respectively. Among infants without underlying medical conditions, group B RSV infection rarely required ventilatory support, in contrast to group A infections (1/90 vs. 13/107; P < .006), and had significantly lower severity indices (mean +/- SD, 0.6 +/- 9 vs. 1.3 +/- 1.9; P = .05). Results confirm earlier findings that group A RSV infection results in greater disease severity than group B infection among hospitalized infants.

Female↗
PubMed1997

Long term follow-up of children hospitalized with respiratory syncytial virus lower respiratory tract infection and randomly treated with ribavirin or placebo.

PURPOSE: To determine the long term effects of ribavirin therapy in children hospitalized for respiratory syncytial virus (RSV) lower respiratory tract infection. METHODS: Fifty-four of 60 children in randomized trials of ribavirin therapy were enrolled in a prospective follow-up study. Subjects were examined annually and had age-appropriate pulmonary function tests; interim histories were obtained from families and personal physicians. RESULTS: Recurrent lower respiratory tract illness was reported at least once for 79% of the ribavirin and 73% of placebo group. In the first 5 years after RSV, 54% of the ribavirin group and 50% of the placebo group reported wheezing. There were no significant differences between the groups in annual rates, timing, or severity of recurrent lower respiratory tract illness. No significant differences in pulmonary function were detected by tests of oxygen saturation, peak expiratory flow and spirometry. CONCLUSIONS: Children in the ribavirin treatment group did not have exacerbated respiratory symptoms compared with those in the control group, and their pulmonary function measurements were equal to those of the placebo-treated group, suggesting no long term adverse effect or benefit of ribavirin therapy.

Antiviral Agents↗
PubMed1997

Enzyme-linked immunosorbent assay for detection of antibody to human herpesvirus 6.

The results obtained with an enzyme-linked immunosorbent assay (ELISA) for detection of human herpesvirus 6 (HHV-6) immunoglobulin G using a single 1:100 dilution of serum correlated well with those found by an indirect fluorescence microscopic assay (IFA) (r = 0.71). Concordant results were found in all 7 paired serum samples obtained from patients with acute primary infections and in 37 of 41 (90.24%) single serum samples. Fourteen serum samples (25%) which yielded nonspecific results by IFA were evaluable by ELISA. In a serologic survey using the ELISA, a disproportionate number of 12-month-old infants had low difference-of-optical-density values, suggesting that maternal antibody might persist beyond a year of age. This finding and the rises in antibody to HHV-6 found in patients with primary cytomegalovirus infections might lead to overestimation of HHV-6 infection rates in young children in seroprevalence studies. Other herpesvirus infections produced lesser effects on anti-HHV-6.

Adolescent↗
PubMed1997

Respiratory syncytial virus (RSV) immune globulin intravenous therapy for RSV lower respiratory tract infection in infants and young children at high risk for severe RSV infections: Respiratory Syncytial Virus Immune Globulin Study Group.

OBJECTIVES: To evaluate the efficacy of high-titer intravenous respiratory syncytial virus immune globulin (RSVIG) in the treatment of children at high risk for severe RSV infection who were hospitalized with proven RSV. METHODS: Infants and young children younger than 2 years with bronchopulmonary dysplasia, chronic lung disease, congenital heart disease, or prematurity (<32 weeks' gestational age), hospitalized with a history of lower respiratory tract infection (LRI) of less than 4 days, were enrolled in this study. Patients were randomized in a blinded fashion to receive either 1500 mg/kg RSVIG or placebo in equal volumes. They were evaluated daily for safety and respiratory scores and for RSV nasal shedding. RESULTS: One hundred seven high-risk children were randomized--54 in the RSVIG group and 53 in the placebo group. Of these children, 51 in each group were considered evaluable. Children with pulmonary disease, congenital heart disease, or prematurity were equally distributed between the two treatment groups. However, two important differences were found in baseline variables between the two groups: there were more patients in the placebo group who had histories of previous LRI and there was a trend toward more severe disease at study entry in the RSVIG group. This was manifested by a higher entry respiratory score in the RSVIG group than in the placebo group (3.4 +/- 0.2 vs 3.1 +/- .01). A higher proportion of children in the RSVIG group (47%) than in the placebo group (28%) required intensive care at entry and mechanical ventilation at study entry (31% RSVIG-treated vs 18% placebo-treated patients). No significant difference was found between groups in the mean unadjusted duration of hospitalization (RSVIG group, 9.10 +/- 1.18 days; control group, 8.17 +/- 1.08 days). When the mean was adjusted for entry respiratory score, likewise, no difference was observed between each group (8.41 +/- 0.97 vs 8.89 +/- .99 days). The lack of efficacy observed in the study primary endpoint was observed in all diagnostic groups. No differences between the RSVIG and placebo groups were observed in the following secondary endpoints: duration of intensive care unit stay, duration of intensive care unit stay for RSV, mechanical ventilation, or supplemental oxygen. No significant differences in adverse events were reported in the RSVIG group (16 children) when compared with the control group (10 children). CONCLUSION: RSVIG treatment was safe but not efficacious in the treatment of children with bronchopulmonary dysplasia, congenital heart disease, or premature gestation who were hospitalized with RSV LRI.

Bronchiolitis↗
PubMed1997

Increasing prevalence of recurrent otitis media among children in the United States.

BACKGROUND: The number of visits for otitis media, the most common diagnosis among preschool children, has increased during the past decade. This study was undertaken to determine whether there has been a concurrent increase in the prevalence of recurrent otitis media among children in the United States and to identify risk factors or demographic changes to explain the increase. METHODS: Secondary analyses of cross-sectional data from the Child Health Supplement to the 1981 and 1988 National Health Interview Surveys (n = 5189 [1981] and n = 6209 [1988]) were done to identify temporal changes in the prevalence and any associated risk factors of recurrent otitis media among children <6 years of age. RESULTS: Recurrent otitis among preschool children increased from 18.7% in 1981 to 26% in 1988 (odds ratio [OR] = 1.6, 95% confidence interval [CI] = 1.4, 1.7). Although the prevalence of recurrent otitis increased with age, the greatest increase in recurrent otitis media occurred in infants (OR = 1.9, CI = 1.3, 2.9). Factors independently associated with recurrent otitis were any allergic condition (OR = 1. 9, CI = 1.7, 2.2); survey year (OR = 1.7, CI = 1.5, 1.9); Black race (OR = .6, CI = .5, .7); Hispanic ethnicity (OR = .8, CI = .6, .9); day care (OR = 1.5, CI = 1.3, 1.7); out-of-home care by an unrelated sitter (OR = 1.3, CI = 1.1, 1.6); and male gender (OR = 1.2, CI = 1. 1, 1.3). From 1981 to 1988, there were significant increases in some risk factors associated with recurrent otitis media, including day care (11% vs 21%) and allergic conditions (14% vs 18%). CONCLUSIONS: We conclude that there has been a significant increase in the prevalence of recurrent otitis media among children in the United States, particularly in infants. The increased prevalence of recurrent otitis media was associated with an increase in the use of child care and a higher prevalence of allergic conditions among children.

Child Day Care Centers↗
PubMed1996

Effect of emergency department immunizations on immunization rates and subsequent primary care visits.

BACKGROUND: The Standards for Pediatric Immunization Practices recommend the routine use of emergency department (ED) encounters for screening the immunization status of children and, if indicated, immunizing them. OBJECTIVE: To test the hypothesis that ED immunizations will improve immunization rates without decreasing subsequent primary care visits. DESIGN: A randomized controlled trial of 2 interventions. Children (aged 6-36 months) (n = 1835) were enrolled in the study in the ED; informed consent was obtained from their parents. They were randomized into 1 of 3 groups: (1) the control group (n = 614), in which no intervention was undertaken; (2) the letter group (n = 610), in which a letter to the primary care physician was written indicating the child's estimated likelihood of being underimmunized; and (3) the ED vaccination group (n = 611), in which, based on a decision rule, those likely to be underimmunized were offered immunizations in the ED. After randomization, parents were interviewed in the ED using a decision rule to estimate the likelihood of the child being underimmunized. One year after enrollment in the study, the medical records of the children at their primary care sites were reviewed to determine the immunization status of the children and primary care use patterns. SETTING: An urban ED and 54 primary care sites in Monroe County, New York. RESULTS: The mean age of the participants was 17.9 months. Medical record review-verified underimmunization rates at the time of the ED visit were 33%, 31%, and 28% for the control, letter, and ED vaccination groups, respectively. The demographic characteristics and baseline immunization rates were not different among study groups. According to the decision rule, 248 children (41%) in the ED vaccination group were likely to be underimmunized. Parents of these 248 children were offered immunizations for their children; 117 (47%) accepted, and their children were immunized (with 230 separate immunizations). One month after the ED visits, the underimmunization rates of the study groups were 31%, 28% (P = .40 compared with the control group), and 23% (P = .002). One year later, these rates were 28%, 25% (P = .20), and 25% (P = .20). No clinically meaningful differences were present at either of these times. One year after the ED visit, no differences in the rates of primary care use were found among groups. CONCLUSIONS: This study provides evidence that the immunization of children in this ED was ineffective at raising their immunization rates; primary care attendance was also unaltered. Major obstacles were as follows: (1) an inability to ascertain accurately the immunization status in the ED and (2) a high rate of parental refusal to accept immunizations in the ED. The standards should be modified to de-emphasize the ED as a routine immunization site for children with access to primary care. Efforts and resources should be directed toward strengthening the primary care system and tracking immunization status.

Child, Preschool↗
PubMed1996

Adjusted variable plots for Cox's proportional hazards regression model.

Adjusted variable plots are useful in linear regression for outlier detection and for qualitative evaluation of the fit of a model. In this paper, we extend adjusted variable plots to Cox's proportional hazards model for possibly censored survival data. We propose three different plots: a risk level adjusted variable (RLAV) plot in which each observation in each risk set appears, a subject level adjusted variable (SLAV) plot in which each subject is represented by one point, and an event level adjusted variable (ELAV) plot in which the entire risk set at each failure event is represented by a single point. The latter two plots are derived from the RLAV by combining multiple points. In each point, the regression coefficient and standard error from a Cox proportional hazards regression is obtained by a simple linear regression through the origin fit to the coordinates of the pictured points. The plots are illustrated with a reanalysis of a dataset of 65 patients with multiple myeloma.

Biometry↗