Search PubMed⌕ Search

Biomedical subjects

C B Hall

Publications and source records attributed to C B Hall.

At least 109 records · Page 6Linked to original sources
PubMed1988

Risk of secondary bacterial infection in infants hospitalized with respiratory syncytial viral infection.

Because infants hospitalized with respiratory syncytial virus (RSV) infection frequently receive antibiotics, our study was undertaken to determine what the actual risk of secondary bacterial infections in patients with RSV infection is and what effect antibiotic treatment might have on the course of illness. In a 9-year prospective study of 1706 children hospitalized with acute respiratory illnesses, 565 children had documented RSV infections. A subsequent bacterial infection rarely developed in those with RSV lower respiratory tract disease. The rate of subsequent bacterial infection was 1.2% in the total group of children infected with RSV, and 0.6% in the 352 children who received no antibiotics. A significantly greater proportion (4.5%) of subsequent bacterial infections occurred in infants who received parenteral antibiotics (p = 0.01), and especially in a subgroup who received parenteral antibiotics for 5 or more days (11%, p less than 0.001). We conclude that the risk of secondary bacterial infection appears to be low for most infants with RSV infection. In a few infants given parenteral broad-spectrum antibiotics the risk may be greater, but whether this is related to the antibiotic therapy or to other risk factors is not clear.

Anti-Bacterial Agents↗
PubMed1987

Immunization with glycoprotein subunits of respiratory syncytial virus to protect cotton rats against viral infection.

The cotton rat model of respiratory syncytial virus infection was used to study immunization with viral glycoproteins. Animals immunized with the purified attachment protein (G) or the fusion protein (F) developed complete pulmonary resistance, but only partial nasal resistance, to challenge with respiratory syncytial virus. Antibody produced to the G protein neutralized virus, whereas antibody to the F protein neutralized virus and also inhibited fusion of infected cells. There was no evidence of enhanced pulmonary pathology in any immunized group.

Animals↗
PubMed1987

Hospital-acquired pneumonia in children: the role of respiratory viruses.

The most frequent agents of pneumonia acquired by children in the hospital are viruses. The characteristics of these nosocomial viral agents differ appreciably from the more classical bacterial nosocomial infections. The viral agents tend to be more contagious, with normal children being as susceptible as the predisposed, high-risk child. The epidemiology of these hospital-acquired infections tends to mimic the patterns of activity of the respiratory viruses in the community. The major causes of nosocomial pneumonia in children are, therefore, the epidemic respiratory viruses--respiratory syncytial virus, the influenza viruses, and the parainfluenza viruses. Respiratory syncytial virus is the most important and frequent of these, causing nosocomial infection in up to 45% of the contact children on infant-toddler wards during community outbreaks. About half of the nosocomial infections involve the lower respiratory tract in these young children. Severe and fatal disease is most likely to occur in neonates and children with underlying cardiac, pulmonary, and immunodeficiency disease. The frequency of lower respiratory tract involvement and nosocomial influenza and parainfluenza viral infections is less, but may pose a serious threat in nurseries and to certain groups of compromised children. The potential hazard of these viral agents on pediatric wards is heightened by the fact that they are frequently not recognized, the incentive and facilities for their diagnosis are often limited, and clinically they may mimic bacterial disease. The source of the nosocomial infections, which may be trivial illnesses in personnel or other patients, may not be suspected, and limiting the spread is difficult.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1987

Children with influenza A infection: treatment with rimantadine.

Treatment with rimantadine of influenza in children and the potential development of resistance in clinical isolates associated with therapy have not been previously studied. We compared rimantadine to acetaminophen therapy in a controlled, double-blind study of 91 children with influenza-like illness. Of 69 children with proven influenza A/H3N2 infection, 37 received rimantadine and 32 received acetaminophen for five days. Children receiving rimantadine showed significantly greater reduction in fever and improvement in daily scores for symptoms and severity of illness during the first three days. Viral shedding also diminished significantly during the first two days but subsequently increased such that by days 6 and 7 the proportion of children shedding virus, as well as the quantity of virus shed, was significantly greater in the rimantadine group. During the seven-day study, of the 22 children in the rimantadine group with serial isolates tested, ten (45.5%) had resistant isolates compared with two (12.5%) of those with serial isolates in the acetaminophen group (P less than .03). Thus, of the total 37 children in the rimantadine group, 27% were found to have resistant isolated compared with 6% in the total group receiving acetaminophen (P less than .04). Furthermore, the mean inhibitory concentration of rimantadine increased with time in the rimantadine group (r = .4, P = .002) but not in the acetaminophen group. Rimantadine therapy, thus, appears to be significantly more effective than acetaminophen in ameliorating the clinical signs and symptoms of influenza in children. Treatment with rimantadine was also associated with increased viral shedding after the medication was discontinued and with the development of resistance in the clinical isolates, the significance of which is unknown.

Acetaminophen↗
PubMed1986

The use of eye-nose goggles to control nosocomial respiratory syncytial virus infection.

We evaluated an eye-nose goggle to determine its usefulness in reducing nosocomial RSV infection in patients and staff members on our infant ward. During a community outbreak of RSV in 1984, infection was assessed by biweekly routine viral cultures on all ward personnel and patients and also by seroconversion in personnel. For three weeks staff members wore the goggles; two (5%) adults and one (6%) child acquired nosocomial infection. During the subsequent three-week study period, goggles were not used and 34% of personnel and 43% of susceptible infants became infected. The use of the disposable eye-nose goggles was associated with a significant decrease in nosocomial RSV infections (P less than .003 for staff and P less than .05 for contact infants).

Adult↗
PubMed1986

Respiratory syncytial viral infection in children with compromised immune function.

For 10 winters, 608 children five years old or younger who were hospitalized with respiratory syncytial virus (RSV) infection were prospectively studied to evaluate the relation between their immune status and the severity of their infection. Forty-seven had been immunocompromised by chemotherapy, steroid therapy, or a primary immunodeficiency disorder. Among the immunocompromised children, those receiving chemotherapy for cancer and those with immunodeficiency disease had more severe RSV disease, with pneumonia occurring at all ages, and a higher mortality rate. Children receiving long-term steroid therapy did not appear to have more severe clinical manifestations than normal children. Viral shedding, however, was significantly greater and more prolonged in the children receiving steroid therapy, and particularly in those receiving chemotherapy or with an immunodeficiency disease. Giant-cell pneumonia was documented in one child with leukemia. Over half the immunocompromised children acquired the RSV infection nosocomially. These findings indicate that children receiving chemotherapy for cancer and those with immunodeficiency disease are at risk for complicated or fatal infections from RSV and should be considered for antiviral and other therapies as they become available. Efforts should also be made to protect compromised children if hospitalization cannot be avoided.

Adrenal Cortex Hormones↗
PubMed1986

Validation of tetrapolar bioelectrical impedance method to assess human body composition.

This study was conducted to validate the relationship between bioelectrical conductance (ht2/R) and densitometrically determined fat-free mass, and to compare the prediction errors of body fatness derived from the tetrapolar impedance method and skinfold thicknesses, relative to hydrodensitometry. One-hundred and fourteen male and female subjects, aged 18-50 yr, with a wide range of fat-free mass (34-96 kg) and percent body fat (4-41%), participated. For males, densitometrically determined fat-free mass was correlated highly (r = 0.979), with fat-free mass predicted from tetrapolar conductance measures using an equation developed for males in a previous study. For females, the correlation between measured fat-free mass and values predicted from the combined (previous and present male data) equation for men also was strong (r = 0.954). The regression coefficients in the male and female regression equations were not significantly different. Relative to hydrodensitometry, the impedance method had a lower predictive error or standard error of the estimates of estimating body fatness than did a standard anthropometric technique (2.7 vs. 3.9%). Therefore this study establishes the validity and reliability of the tetrapolar impedance method for use in assessment of body composition in healthy humans.

Adult↗
PubMed1985

Ribavirin treatment of respiratory syncytial viral infection in infants with underlying cardiopulmonary disease.

Aerosolized ribavirin was evaluated in the treatment of respiratory syncytial virus lower respiratory tract disease in 53 infants, 36 of whom had underlying diseases. Of the total infants, 26 were studied in a double-blind, placebo-controlled manner; 14 received ribavirin and 12 received placebo, a water aerosol, for an average of five days. When the infants with bronchopulmonary dysplasia and congenital heart disease treated with ribavirin were compared with those receiving placebo, the treated infants showed a significantly faster rate of improvement in their illness severity score. The degree of improvement in the total group of infants receiving ribavirin compared with those receiving placebo was similarly greater, and at the end of therapy significantly greater improvement was also demonstrated in their arterial blood gas values and in the amount of virus shed from their nasal washes. No toxic or adverse effects of the aerosol therapy were observed in any of the 53 infants studied, and resistance to ribavirin did not develop in any of the respiratory syncytial virus strains isolated, despite prolonged treatment in some of the more ill infants.

Bronchopulmonary Dysplasia↗
PubMed1985

Aristolochic acid is mutagenic and recombinogenic in Drosophila genotoxicity tests.

Aristolochic acid (AA) has been tested for genotoxic activity in three different assays with Drosophila melanogaster (i-iii). AA induced sex-linked recessive lethals (i) and chromosome losses (ii) in male germ cells. In a newly developed fast assay with somatic cells of larvae (iii), AA induced mutant single spots as well as twin spots. The data indicate that in addition to the mutagenic activity, AA also possesses recombinogenic activity leading to somatic recombination in mitotically active cells. The experimental labor involved to detect the genotoxic activity of AA was lowest with the somatic cell assay.

Animals↗
PubMed1985

Identification of infants unlikely to have serious bacterial infection although hospitalized for suspected sepsis.

During a 2-year period, 233 infants younger than 3 months were prospectively studied to determine whether physical examination, white blood cell and band count, and urinalysis could identify infants unlikely to have serious bacterial infections. Only previously healthy infants (born at term, no perinatal complications, no previous or underlying diseases, no previous antibiotic therapy) were studied. One hundred forty-four (62%) of the 233 infants were considered unlikely to have serious bacterial infections, because they did not have physical findings consistent with ear, soft tissue, or skeletal infection, had between 5000 and 15,000 white blood cells/mm3, had less than 1500 bands/mm3, and urinalysis yielded normal findings. Eighty-nine (38%) infants did not meet one or more of these criteria and were classified as being at high risk for serious bacterial infection. Only one (0.7%) of the 144 infants in the low-risk group had a serious infection, compared with 22 (25%) of the 89 infants in the high risk group (P less than 0.0001). None of the infants in the low-risk group had bacteremia, compared with nine (10%) of the 89 infants in the high-risk group (P less than 0.0005). Neither traditional risk factors, such as age, sex, and temperature, nor other signs, symptoms, or laboratory findings were adequate predictors of serious bacterial infection. We conclude that previously healthy infants younger than 3 months with an acute illness are unlikely to have serious bacterial infection if they have no findings consistent with ear, soft tissue, or skeletal infections and have normal white blood cell and band form counts and normal urine findings.

Age Factors↗
PubMed1985

Variable adherence of fimbriated Haemophilus influenzae type b to human cells.

The attachment of isogenic fimbriated and nonfimbriated Haemophilus influenzae type b variants to human cells was studied by using a radioactive assay and an indirect immunofluorescent assay. As described previously, fimbriated H. influenzae variants adhered to a greater extent than nonfimbriated variants to human buccal epithelial cells (2.1 and 0.29 bacteria per cell, respectively, as determined by the radioactive assay [P less than 0.05]; 7.6 and 1.6 bacteria per cell, respectively, as determined by the immunofluorescent assay [P less than 0.01]). As the concentration of fimbriated bacteria was increased, so were the numbers of adherent bacteria; in contrast, increasing the bacterial concentration had a much smaller effect on adherence of nonfimbriated H. influenzae type b. The distribution of bacteria on the buccal cells also differed. Whereas 37% of the buccal cells failed to bind nonfimbriated H. influenzae type b, failure to bind was observed for only 4% of the buccal cells exposed to fimbriated H. influenzae. In contrast, adherence to human foreskin fibroblasts was low regardless of the presence of fimbriae. On the other hand, fimbriated H. influenzae type b adhered less well than nonfimbriated variants to HEp-2 cells (1.6 and 3.8 bacteria per cell, respectively, as determined by the radioactive assay [P less than 0.05]; 1.3 and 4.8 bacteria per cell, respectively, as determined by the immunofluorescent assay [P less than 0.02]). Whereas adherence to HEp-2 cells increased considerably as the concentration of nonfimbriated bacteria was increased, there was only a small enhancement of adherence with an increase in the concentration of fimbriated H. influenzae type b. Furthermore, only 16% of the HEp-2 cells failed to bind nonfimbriated H. influenzae type b, whereas 50% failed to bind fimbriated H. influenzae type b. These data indicate that H. influenzae type b may contain two adhesins. One is associated with fimbriae and enables adherence to buccal cells, whereas the other is nonfimbrial and is associated with adherence to HEp-2 cells. It is not known whether either of these adhesins plays a role in pathogenesis.

Adhesiveness↗
PubMed1985

Hemadsorption focus assay for growth of influenza and parainfluenza viruses in human dermal fibroblasts.

An assay for virus-induced hemadsorption foci in cultures of human dermal fibroblasts is described. The assay allows determination of activity of species-specific as well as nonspecific antiviral agents or biological factors, such as interferons. The assay may be used for abortive (e.g., influenza virus) and productive (e.g., parainfluenza virus) infections of human fibroblasts.

Fibroblasts↗
PubMed1985

The childhood health effects of an improved water supply system on a remote Panamanian island.

The incidence of diarrhea, respiratory disease, and skin infections was prospectively determined after the introduction of a system which distributed unlimited quantities of high quality fresh water to each of the 150 housing units on Tupile, an island devoid of fresh water located off Panama's Caribbean coast and inhabited by 1,500 Cuna Indians. Tupile residents used 7.1 liters of water/person/day compared to the 2.3 usage rate of inhabitants on Achutupo, the control island. Despite ready availability of water in each household, Tupile residents continued to store water in contaminated vessels prior to use. Forty percent of stored water samples tested on Tupile and 45% on Achutupo were contaminated with E. coli organisms. There were 4.7 episodes/child year (E/Y) of acute diarrhea on Tupile compared with the 3.5 rate on Achutupo. The rotavirus infection rate on Tupile was 0.8 E/Y compared with 0.2 E/Y on Achutupo. Infection rates for Norwalk virus, respiratory syncytial virus and Coxsackie B 1-6 viruses were similar on both islands. Respiratory disease rates were high on both islands (2.2 E/Y on Tupile, 2.7 E/Y on Achutupo). Achutupo had much higher rates of impetigo and scabies (0.6 E/Y and 2.5 E/Y, respectively) than Tupile (0.2 E/Y and 1.4 E/Y). Provision of the water distribution system had a beneficial effect on the incidence of water-washed diseases (impetigo and scabies), but at best had no effect on diarrheal disease.

Child↗
PubMed1985

Atypical bacterial infections explained by a concomitant virus infection.

Because both viral and bacterial infections are common during early childhood, dual infections are not unexpected. However, the clinical manifestation of such combined infections may be, difficult to interpret, and they are often misdiagnosed as "atypical bacterial infection." Five patients with concomitant viral-bacterial infections are described. In all five cases, virus detection enabled the physicians to better understand an otherwise puzzling clinical presentation. In view of the recent progress in rapid viral diagnoses and the potential of antiviral drugs, the possibility of dual infection should be investigated more often.

Bacterial Infections↗