Search PubMed⌕ Search

Biomedical subjects

C B Hall

Publications and source records attributed to C B Hall.

At least 127 records · Page 7Linked to original sources
PubMed1984

Respiratory syncytial virus-related apnea in infants. Demographics and outcome.

Medical records of 261 hospitalized patients less than 1 year old with documented respiratory syncytial virus (RSV) infection were reviewed to determine the incidence of RSV-associated apnea and the accompanying risk of subsequent apnea or death. Apnea in association with RSV infection occurred in 18% of the infants. Premature birth and a young postnatal age were risk factors for development of apnea with RSV disease. Apnea of prematurity appeared to be a significant risk factor for RSV apnea development in infants with a gestational age of 32 weeks or less at birth, but infants with RSV apnea did not appear to be at risk for subsequent apnea. These results suggested that in hospitalized infants, RSV apnea may be related to immaturity of respiratory drive. Two of the 48 infants with RSV apnea subsequently died during the first year of life.

Apnea↗
PubMed1984

Somatic mutation and recombination test in Drosophila melanogaster.

A novel test system for the detection of mutagenic and recombinogenic activity of chemicals is described in detail. Drosophila melanogaster larvae trans-heterozygous for the mutations multiple wing hairs (mwh) and flare (flr) are exposed to the test compounds for various periods of time ranging from 96 hr to 1 hr. Induced mutations are detected as single mosaic spots on the wing blade of surviving adults that show either the multiple wing hairs or flare phenotype. Induced recombination leads to mwh and flr twin spots and also to a certain extent, to mwh single spots. Recording of the frequency and the size of the different spots allows for a quantitative determination of the mutagenic and recombinogenic effects. This and earlier studies with a small set of well-known mutagens indicate that the test detects monofunctional and polyfunctional alkylating agents (ethyl methanesulfonate, diepoxybutane, mitomycin C, Trenimon), mutagens forming large adducts (aflatoxin B1), DNA breaking agents (bleomycin), intercalating agents (5-aminoacridine, ICR-170), spindle poisons (vinblastine), and antimetabolites (methotrexate). In addition, the test detects mutagens unstable in aqueous solution (beta-propiolactone), gaseous mutagens (1,2-dibromoethane), as well as promutagens needing various pathways of metabolic activation (aflatoxin B1, diethylnitrosamine, dimethylnitrosamine, mitomycin C, and procarbazine). The rapidity and ease of performance as well as the low costs of the test necessitate a high priority for validation of this promising Drosophila short-term test.

Animals↗
PubMed1984

Long-term prospective study in children after respiratory syncytial virus infection.

We have prospectively evaluated for the past 8 years 29 children who were hospitalized during infancy with acute lower respiratory tract illness caused by respiratory syncytial virus (RSV). No differences in the prevalence of a family history of atopy or breast-feeding in these infants compared with controls were noted. However, a history of parental smoking was significantly associated with hospital admission for RSV lower respiratory tract disease. Evidence of atopy, as defined by serum IgE levels and radioallergosorbent testing, have developed in only three (10%) of 29 children. Six children (21%) continue to have recurrent lower respiratory tract disease. Fifty-five percent of these children had abnormally low oxyhemoglobin levels (SaO2) measured by ear oximetry for the first 3 to 4 years after the acute illness. Twenty-one percent have persistently low SaO2 levels during the eighth year of follow-up. Spirometric values indicate evidence of peripheral airway obstruction. These studies suggest that an association between RSV lower respiratory tract infections and chronic abnormalities of pulmonary function may be detected sequentially through the first 8 years of life. These abnormalities are not limited to those children developing an atopic state during that same time period.

Breast Feeding↗
PubMed1983

Aerosolized ribavirin treatment of infants with respiratory syncytial viral infection. A randomized double-blind study.

We evaluated a new antiviral agent, ribavirin, in the treatment of infants hospitalized with lower-respiratory-tract disease from respiratory syncytial virus. Ribavirin or placebo was administered to 33 infants in a double-blind manner by continuous aerosol for three to six days. Seventeen infants were treated with placebo, and 16 with ribavirin. By the end of treatment, infants receiving ribavirin had significantly greater improvement in their overall score for severity of illness, in lower-respiratory-tract signs, and in arterial oxygen saturation. Viral shedding was also diminished in the treated groups as compared with the placebo group. No side effects or toxicity were associated with the aerosol therapy. Isolates of respiratory syncytial virus obtained from the infants over the course of therapy showed no change in sensitivity to ribavirin.

Aerosols↗
PubMed1983

Ribavirin treatment of experimental respiratory syncytial viral infection. A controlled double-blind study in young adults.

The effect of ribavirin aerosol on experimental respiratory syncytial virus (RSV) infection was evaluated in a double-blind controlled study of 16 young adult volunteers. Two days after intranasal inoculation with RSV, half of the subjects were treated with a small-particle aerosol of ribavirin and half with placebo for a total of 12 hours each day for three days. Seven of eight placebo-treated and six of eight ribavirin-treated subjects became infected. Viral shedding was diminished in the ribavirin-treated group. The proportion of infected volunteers still shedding virus on days 6 through 9 was significantly less than in the placebo-treated group. Ribavirin appeared to have no effect on minor upper respiratory tract signs, but systemic complaints and fever occurred significantly less often in the ribavirin-treated group. Ribavirin aerosol therapy was well tolerated and produced no significant changes in pulmonary function test results or signs of toxicity. This suggests that such therapy might be further evaluated in infants with RSV lower respiratory tract disease.

Adult↗
PubMed1983

Rapid detection of respiratory syncytial virus with a monoclonal antibody.

We developed an indirect fluorescent-antibody test employing a mouse monoclonal antibody directed against the nucleoprotein of RSV for rapid detection of respiratory syncytial virus (RSV). This test demonstrated distinctive fluorescent inclusions in HEp-2 cells infected with 24 RSV isolates collected during 6 previous years but not in cells infected with 13 other respiratory viruses. Examination of nasal cells of 100 infants with acute respiratory illness showed that the indirect fluorescent-antibody test employing the monoclonal antibody was 79% sensitive and 100% specific, as compared with the combination of both culturing and a similar indirect fluorescent-antibody test with commercial anti-RSV serum. This monoclonal antibody is an easily produced, well-characterized, sensitive, and specific reagent for the rapid detection of RSV antigen.

Antibodies, Monoclonal↗
PubMed1983

The nosocomial spread of respiratory syncytial viral infections.

Respiratory syncytial virus is a regular winter visitor that is highly contagious among persons of all ages. It is the major nosocomial pathogen on infant and toddler wards, and has recently been recognized as also causing appreciable nosocomial illness in the elderly. Control of the spread of this virus has been difficult, but transmission appears to require close contact via large-particle aerosols or via fomites. Environmental conditions affect the survival of the virus on varying surfaces and skin, but self-inoculation after touching contaminated surfaces appears to be an important mode of transmission.

Cross Infection↗
PubMed1982

Respiratory syncytial viral infection in infants with congenital heart disease.

Occasional reports have suggested that infants with congenital heart disease may have an increased risk of severe illness from respiratory syncytial virus (RSV) infection. We prospectively studied 699 infants hospitalized during the winters of 1976 through 1980, when RSV was prevalent in the community; 229 of these infants had proved RSV infections acquired either before admission or during hospitalization; 27 had both congenital heart disease and RSV infection, and 46 had congenital heart disease without RSV infection. Infected infants with congenital heart disease had significantly more severe illness than those without congenital heart disease, as judged by the requirement for intensive care and assisted ventilation and by the mortality rate (37 per cent vs. 1.5 per cent, P less than 0.01). The infection was acquired nosocomially by 21 per cent of infected infants; the mortality rate from nosocomial infection was also higher in infants with congenital heart disease (44 per cent vs. 5 per cent, P less than 0.01). Pulmonary hypertension was the one condition particularly associated with severe RSV illness. Eight of the 11 infants (73 per cent) with congenital heart disease and pulmonary hypertension died during their RSV illness. The courses in infants with congenital heart disease with and without RSV infection were also compared. Their ages, types of cardiac lesions, and incidence of pulmonary hypertension were similar, but the infants with RSV infection had a higher mortality rate (37 per cent vs. 6.5 per cent, P less than 0.1).

Cross Infection↗
PubMed1982

Concurrent outbreaks of rhinovirus and respiratory syncytial virus in an intensive care nursery: epidemiology and associated risk factors.

An outbreak of viral respiratory disease occurred in eight infants in a neonatal intensive care unit during the 1980 winter respiratory season. Four infections with respiratory syncytial virus and four infections with rhinovirus were identified. Epidemiologic investigation revealed that viral respiratory infection was significantly associated with intubation with orotracheal tubes (P = 0.001), with the presence of both a nasal feeding tube plus an orotracheal tube together (P = 0.007), and with assisted ventilation (P = 0.009) when compared to uninfected controls. Twenty-seven of 85 (30.6%) personnel working in the unit at the time of the outbreak reported a history of upper respiratory illness during the week prior to the outbreak, and 46 (54.1%) of them had had contact with patients in areas of the hospital where patients infected with RSV and rhinovirus were housed. The data suggest that both viruses were transmitted to the babies by hospital personnel. Rhinoviruses can be nosocomial pathogen in neonates with compromised pulmonary function, and the clinical presentation of rhinovirus infection in neonates may be difficult to distinguish from that produced by RSV.

Cross Infection↗
PubMed1981

Kawasaki syndrome: description of two outbreaks in the United States.

Investigation of two outbreaks of Kawasaki syndrome (KS) in the United States in 1979 and in 1980 revealed no evidence of person-to-person transmission or of a common-source exposure among patients. Questionnaire data showed that KS was more likely to occur in children of middle and upper socioeconomic status than in those of lower status (P less than 0.05 and P less than 0.001 for the respective outbreaks) and that patients with KS had a higher incidence of an antecedent, primarily respiratory illness than did controls matched for age, sex, and race (83% of patients in the first outbreak vs. 30% of one control group, P less than 0.01, and vs. 36% of another control group, P less than 0.02; and 56% of patients in the second outbreak vs. 32% of their controls, P less than 0.02). However, laboratory studies did not identify an etiologic agent for either KS or for the antecedent illness that may be a risk factor for KS.

Adolescent↗
PubMed1981

Nosocomial respiratory syncytial viral infections. Should gowns and masks be used?

The efficacy of infection control procedures utilizing gowns and masks in the control of nosocomial respiratory syncytial virus (RSV) infections was evaluated by comparing the rate of nosocomial RSV infections in infants and ward personnel during two sequential periods when gowns and masks were used (period 1) and not used (period 2). All patients (162) and staff (36) on our infants' ward were examined for signs of respiratory infection and had nasal washes obtained for viral isolation every two to four days for two months. Nosocomial RSV infection was identified in a total of 19 infants. Eight of these occurred in period 1 for a nosocomial infection rate of 32% of contact infants who were hospitalized for seven or more days. In comparison, 11 (41%) of the contact infants hospitalized for seven or more days in period 2 became infected. These findings suggest that the additional routine use of masks and gowns does not result in measurable benefit in controlling the nosocomial spread of RSV infection to infants or to ward personnel.

Child, Preschool↗
PubMed1981

Nosocomial viral respiratory infections: perennial weeds on pediatric wards.

The frequency and importance of nosocomial infections of the respiratory tract in pediatrics have generally been underestimated. In part this has resulted from the emphasis on bacterial infections which occur primarily in select at-risk populations. Most respiratory infections in pediatric patients, hospital- and community-acquired, are viral and all patients are potentially susceptible The epidemiologic patterns of these viral respiratory agents on the ward mirror those seen in the community in terms of frequency, season, age affected and severity of illness. Hence, the most frequent nosocomial agents are the viruses that occur in outbreaks or epidemics and cause respiratory illness, epidemic respiratory viruses--respiratory syncytial virus, which causes the greatest morbidity and mortality; influenza, and the parainfluenza viruses. Their import, as exemplified by respiratory syncytial virus, results from (1) the severity of disease produced in young children, which is magnified in those hospitalized with certain underlying conditions; (2) the abundant and prolonged viral shedding, allowing easy spread; (3) the potential susceptibility of all patients and staff, since infections recur throughout life; and (4) the difficulty in controlling nosocomial spread.

Child, Preschool↗
PubMed1981

Diagnosis of viral diseases -- today and tomorrow.

Although there is more basic knowledge about viruses than about any other living unit, clinical application of the knowledge has not kept pace. Methods of diagnosis have proliferated, but the question remains: which of the 500 viruses now known to humans is most likely to be causing your patient's symptom? The patient's age and immunologic status and the season of the year all may be indicative factors.

Clinical Laboratory Techniques↗
PubMed1981

Interferon production by human mononuclear leukocytes: differences between respiratory syncytial virus and influenza viruses.

The ability of respiratory syncytial virus (RSV) to induce interferon production by human mononuclear leukocytes was compared with that of influenza viruses. Cell culture fluids were assayed for interferon activity 1, 3 and 7 days after exposure to RSV or to one of two subtypes of influenza A virus (H0N1 and H3N2). RSV induced interferon production inconsistently and in low titers. Varying the multiplicity of infection did not improve the ability of RSV to induce interferon production. In contrast, influenza viruses were effective inducers of interferon production. Seropositivity to the influenza virus strains was not associated with increased interferon titers. Interferon produced after exposure to RSV or to the influenza viruses was resistant to low pH treatment. The data suggest that interferon production may not be a major component of human immunological defense against RSV infection.

Adult↗