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Biomedical subjects

N Guerra

Publications and source records attributed to N Guerra.

11 recordsLinked to original sources

Safety and immunogenicity of acellular diphtheria-tetanus-pertussis and Haemophilus conjugate vaccines given in combination or at separate injection sites.

This prospective, double-blind, randomized trial compared the immunogenicity and reactogenicity of acellular diphtheria-tetanus-pertussis vaccine and Haemophilus influenzae type b conjugate vaccine-diphtheria toxoid conjugate, given at separate injection sites or at a single site, in 79 children 18 months of age who had received three prior immunizing doses of whole-cell diphtheria-tetanus-pertussis vaccine. No significant differences were observed.

Antibodies, Bacterial

Duration of rifampin chemoprophylaxis for contacts of patients infected with Haemophilus influenzae type B.

Rifampin is recommended as a prophylactic treatment for intimate contacts of young children who develop invasive infections with Haemophilus influenzae type B (Hib). A 4-day course of rifampin (20 mg/kg of body weight per day, not to exceed 600 mg as a maximum single daily dose) is 95% effective in eradicating pharyngeal colonization with Hib, thus effectively reducing the risk of both associated patients and recurrent illness in index patients less than 2 years old. This study compares rates of eradication of pharyngeal colonization with Hib for 2- and 4-day courses of rifampin therapy. One hundred sixty-three patients with Hib infection were treated at Children's Hospital of Pittsburgh between January 1986 and December 1988; prophylaxis was recommended for 128. Participating families were randomized to receive either 2- or 4-day therapy. Throat swabs were obtained from contacts prior to therapy. Repeat cultures were obtained from colonized contacts 2 days after completing rifampin and again on all contacts 7 to 10 days after completing therapy. Of 68 participating families, 34 received 2-day and 34 received 4-day therapy with rifampin. Twenty-two of 24 colonized contacts in the 2-day group and 17 of 18 in the 4-day group had negative cultures for Hib on follow-up. Two-day therapy with rifampin appears to be as effective as 4-day treatment in the eradication of Hib pharyngeal colonization.

Administration, Oral

Frequency and severity of infections in day care: three-year follow-up.

This study was undertaken to compare prospectively the frequency, nature, and severity of infections in children participating in three types of child care arrangements: home care, group care (two to six children), and day care (seven or more children). Children were enrolled at birth and observed for at least 36 months. The families were telephoned every 2 weeks to record on a standardized form the type and severity of illness during the previous interval. Children remaining in their original child care group for 1, 2, or 3 years were compared with regard to the frequency and severity of illness. Each child care group had the highest number of infections in year 2. Children in day care had more respiratory infections during each year than children in home care, but the magnitude of the differences decreased in year 3. When the child care groups were compared for the proportion of children with more than six illness per year or more than 60 days of respiratory illness per year, significant differences observed in years 1 and 2 for day care children compared with home care children were no longer significant in year 3. We conclude that there is a trend toward stabilized or decreased rates of infection, duration of illness, and risk of hospitalization for children remaining in day care for 3 years.

Child Care

[Aging and left ventricular diastolic function].

Several studies have demonstrated that physiological aging significantly affects cardiovascular function. Experimental researches, conducted on cardiac muscle of senescent animals, have shown a prolongation of both contraction and relaxation times. This phenomenon was explained by a reduced Ca(++)-stimulated ATPase pump activity, responsible for the reduced sarcoplasmic reticulum Ca++ uptake rate. The myofilament response to Ca++ in the aging heart is normal as are peak contractile force production and post-extrasystolic twitch potentiation during continual paired stimulation. On the other hand, the inotropic response to cardiac glycosides and beta-adrenoceptor stimulation is diminished in senescent compared to adult myocardium. This decreased contractility could result mainly from mechanisms controlling Ca++ reuptake from sarcoplasmic reticulum and relaxation time (diastolic phase) rather than those determining force generation and contraction time (systolic phase). Age-related physiologic structural changes are not associated with significant variations in left ventricular diastolic and systolic sizes, but they seem a direct consequence of the rising systolic blood pressure observed in these age decades. Myocardial hypertrophy should not be considered a specific marker of the senescent heart, but rather an adaptive response to increased afterload conditions. As regard the relationship between age and diastole, it is important to underline that the alterations in aging cardiac muscle function primarily involve the isovolumic relaxation time and diastolic phase. With age, the early diastolic phase declines while the contribution of atrial contraction to ventricular diastolic filling increases as well as the isovolumic relaxation time.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging

Upper respiratory tract infections in young children: duration of and frequency of complications.

This study was performed to determine the usual duration of community-acquired viral upper respiratory tract infections and the incidence of complications (otitis media/sinusitis) of these respiratory tract infections in infancy and early childhood. Children in various forms of child-care arrangements (home care, group care, and day care) were enrolled at birth and observed for 3 years. Families were telephoned every 2 weeks to record on a standardized form the type and severity of illnesses experienced during the previous interval. Only children remaining in their original child-care group for the entire study period were compared. The mean duration of an upper respiratory tract infection varied between 6.6 days (for 1- to 2-year-old children in home care) and 8.9 days (for children younger than 1 year in day care). The percentage of apparently simple upper respiratory tract infections that lasted more than 15 days ranged from 6.5% (for 1- to 3-year-old children in home care) to 13.1% (for 2- to 3-year-old children in day care). Children in day care were more likely than children in home care to have protracted respiratory symptoms. Of 2741 respiratory tract infections recorded for the 3-year period, 801 (29.2%) were complicated by otitis media. During the first 2 years of life, children in any type of day care were more likely than children in home care to have otitis media as a complication of upper respiratory tract infection. In year 3, the risk of otitis media was similar in all types of child care.

Age Factors

Safety, tolerability, and immunogenicity of concurrent administration of Haemophilus influenzae type b conjugate vaccine (meningococcal protein conjugate) with either measles-mumps-rubella vaccine or diphtheria-tetanus-pertussis and oral poliovirus vaccines in 14- to 23-month-old infants.

In 1985, the first capsular polysaccharide (polyribosylribitol-phosphate [PRP]) vaccine for Haemophilus influenzae type b was licensed and recommended for routine use in children between 24 and 60 months of age. In the United States, approximately 75% to 90% of invasive disease due to H influenzae type b occurs in infants younger than 24 months, a population for whom H influenzae type b polysaccharide vaccine is inadequately immunogenic and protective. In an effort to enhance the immunogenicity of H influenzae type b polysaccharide vaccine for children in the most susceptible age groups, conjugate vaccines have been developed in which the capsular PRP of H influenzae type b has been bound to a variety of carrier proteins, thereby conferring the vaccines with thymic-dependent attributes. One such conjugate vaccine, in which the carrier protein is diphtheria toxoid (PRP-D), was licensed in 1987 and has been recommended since 1988 for routine use in children 18 months of age and older. A second conjugate vaccine, in which an oligosaccharide derivative of H influenzae type b capsular PRP is coupled to CRM, a nontoxic mutant diphtheria toxin (oligo-CRM), was licensed in 1988 and is a sanctioned alternative to PRP-D. Another investigational conjugate vaccine, in which the polysaccharide is linked to the outer membrane protein of Neisseria meningitidis group B (PRP-OMPC), has been demonstrated to be both safe and immunogenic when administered in a two-dose schedule to 2- to 6-month-old infants. However, anti-PRP antibody levels decline significantly during the ensuing 10 to 15 months; they rise significantly in response to booster doses of either PRP or PRP-OMPC administered 10 to 15 months after the initial priming doses of PRP-OMPC.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Bacterial

Subacute sinusitis in children.

The bacteriologic characteristics of subacute maxillary sinusitis have not been delineated in the pediatric age group. Forty children between the ages of 2 and 12 years with respiratory symptoms for at least 30 but less than 120 days were evaluated. Nasal discharge and cough were the most prominent symptoms. Common radiographic findings were diffuse opacification and mucosal thickenings. Sinus aspiration was performed on 52 sinuses of 40 children. Bacterial colony counts greater than or equal to 10(4) colony-forming units per milliliter were found in 30 (58%) of 52 sinus aspirates obtained from 26 (65%) children. The bacterial species most commonly recovered were Streptococcus pneumoniae, Haemophilus influenzae, and Branhamella catarrhalis. Twenty-five percent of the maxillary sinus isolates were beta-lactamase producing; however, many of these were recovered from patients who had recently received antimicrobial therapy. Subacute and acute maxillary sinusitis are similar in regard to causative organism, clinical presentation, and radiographic findings.

Child

Frequency and severity of infections in day care.

This study was undertaken to compare prospectively the frequency, nature, and severity of infections experienced by children in three types of child care arrangements: home care, group care (two to six children), and day care (seven or more children). Children were enrolled at birth and observed for 12 to 18 months. At entry there were 159 children in home care, 40 in group care, and 45 in day care. The families were telephoned every 2 weeks to record on a standardized form the type and severity of illnesses experienced during the previous interval. Severe illnesses were defined by high fever, duration exceeding 10 days, or physician visit. Children remaining in their original child care group for at least 1 year were compared with regard to the frequency and severity of illness. Children in group care and day care were more likely than children in home care to experience at least six respiratory infections, more than 60 days of illness, and more than four severe illnesses (P less than 0.01). Similarly, life table analyses showed that children in home care had fewer episodes of infection than did children in day care (P less than 0.01). Although no children were hospitalized because of acute infections during the first year of study, hospitalization for myringotomy and tube placement occurred in 21% of children in day care and 3% of children in home care (P less than 0.01).

Actuarial Analysis

[Influence of the angiocardiographic severity of ischemic heart disease on QTc duration].

The influence of severity of coronary artery disease (CAD) on the duration of corrected electrical systole (QTc) and the prognostic value to predict sudden death of this index were retrospectively evaluated in 123 non-consecutive patients with history of stable angina who underwent cardiac catheterization. Fifteen patients had no angiographic evidence of CAD (O-V group). The 108 patients with a greater than or equal to 70% luminal diameter narrowing of a major coronary artery were further subdivided: 23 patients had 1-vessel (1-V group), 40 patients had 2-vessel (2-V group) and 45 had 3-vessel (3-V group) coronary artery disease; 26 patients showed normal left ventricular (LV) wall motion (A group), 57 patients showed asynergic contraction of 1 or 2 LV areas (B group) and 25 patients showed 3 or more areas of asynergy and/or aneurysm. Sixty-one patients had a previous myocardial infarction (MI). QT interval, calculated in the lead where it was longer, on 12-lead resting electrocardiograms recorded at a paper speed of 25 mm/sec, was corrected by the formula: QTc = QT/square root R-R. The follow-up was performed by telephone. At the time of angiography there was no significant difference in QTc duration between the different groups according to the severity of CAD (O-V, 1-V, 2-V and 3-V groups). Patients showing three or more areas of abnormal segmental wall motion and/or aneurysm (C group) had a significantly longer QTc (p less than 0.05) than patients with normal LV wall motion (A group).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult