Biomedical subjects

P Christenson

Publications and source records attributed to P Christenson.

At least 19 recordsLinked to original sources

PubMed1994

Protection provided by Haemophilus influenzae type b conjugate vaccines in Los Angeles County: a case-control study.

The objective was to assess the degree of disease control and to evaluate the protective efficacy of licensed Haemophilus influenzae type b (Hib) conjugate vaccines (HbOC, PRP-OMP, PRP-D) used routinely in children 2 to 35 months of age. We conducted a case-control study in Los Angeles County between January 1, 1991, and December 31, 1992, and a cohort analysis of Hib cases between 1983 and 1992. For the case-control study 105 cases of invasive Hib disease were identified and 767 geographically and age-matched controls were selected by random digit telephone dialing. Sixteen HbOC vaccine failures occurred > 14 days after a single dose of vaccine, 6 vaccine failures after 2 doses and 3 failures after 3 doses; 2 cases occurred 6 and 12 days, respectively, after an initial dose of HbOC. The protective efficacy of a single HbOC vaccine dose was 71.1% (95% confidence interval (CI), 37.5 to 87.2%). After 2 doses the efficacy was 88.8% (95% CI, 59.5 to 96.9%) and after 3 doses it was 94.4% (95% CI, 68.0% to 99.0%). Similar 95% CIs were seen for 1 and 2 doses of PRP-OMP vaccine. Adjustment of efficacy estimates for potential confounding variables did not significantly alter the results. Despite relatively low rates of immunization (20 to 60%) the rates of Hib disease decreased strikingly between 1990 and 1992 (from 24.2 to 4.4/100,000 children < 5 years of age). The HbOC conjugate vaccine, used predominantly but incompletely during this period, provided substantial protection against invasive Hib disease in children immunized between 2 and 35 months of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Case-Control Studies↗

PubMed1993

A randomized trial of low-air-loss beds for treatment of pressure ulcers.

OBJECTIVE: To assess the effectiveness of low-air-loss beds for the treatment of pressure ulcers in nursing homes. DESIGN: Prospective, randomized, clinical trial. SETTING: Three teaching nursing homes in Los Angeles, Calif. SUBJECTS: Eighty-four nursing home residents with trunk or trochanter pressure ulcers (Shea stage > or = 2). INTERVENTIONS: Subjects were randomly assigned to use either a low-air-loss bed (n = 43) or a 10-cm corrugated foam mattress (n = 41) throughout the healing of their ulcers. OUTCOME MEASURES: Ulcers were assessed twice weekly using surface area and two observational scales (median follow-up, 37.5 days; range, 4 to 571 days). RESULTS: Groups were similar with respect to demographics, medical variables, wound care, and early dropouts. Results indicate more than a threefold improvement in median rate of healing for low-air-loss beds compared with foam mattresses (9.0 vs 2.5 mm2/d; P = .0002). This finding was true for deep as well as superficial ulcers (deep ulcers, 9.9 vs 0.7 mm2/d; P = .02; superficial ulcers, 9.0 vs 3.2 mm2/d; P = .004). Cox regression models revealed that the bed, ulcer depth, and fecal continence had independent effects on healing. After controlling for fecal continence, the deep and superficial subgroups using low-air-loss beds remained 2.5 times more likely to heal in a given length of time compared with those using foam mattresses (combined cure probability ratio, 2.66; 95% confidence interval, 1.34 to 5.17; P < .004). CONCLUSION: Low-air-loss beds provide substantial improvement compared with foam mattresses despite other factors in pressure ulcer healing.

Aged↗

PubMed1993

Clinical and laboratory diagnosis of pertussis in the regions of a large vaccine efficacy trial in Germany.

As a support service for a pertussis vaccine efficacy trial, a central diagnostic laboratory was established. Physicians in the geographic areas of the planned study were encouraged to send nasopharyngeal specimens from children and household contacts with cough illnesses whether or not the illnesses were typical of pertussis. From April, 1991, to February, 1992, 3629 specimens were received and in 601 instances (16.6%) Bordetella pertussis was isolated. Only 3.3% of patients with positive cultures had received pertussis vaccine whereas 16.1% of culture-negative patients had received vaccine (P < 0.0001). Fever was more common (12.2%) in patients with negative cultures compared with those with positive cultures (5.4%) (P < 0.0001). B. pertussis isolation rates fell markedly after 21 days of cough. Significantly more patients with negative cultures compared with those with positive cultures had been treated with erythromycin (8.5 vs. 2.9%; P < 0.0001). Patients with cough for greater than 4 weeks and specimen collection within 2 weeks of cough onset had a B. pertussis isolation rate of 59%. Similarly if whoop occurred under the same circumstances the isolation rate was 80%. In this study 25.5% of patients with culture confirmed pertussis had illnesses with cough of less than 21 days duration. This finding suggests to us that a pertussis case definition in efficacy trials that requires cough of 21 days is excessively restrictive.

Adolescent↗

PubMed1992

Risk factors for invasive Haemophilus influenzae type b in Los Angeles County children 18-60 months of age.

Potential factors that confer risk or protection for invasive Haemophilus influenzae type b disease were evaluated in Los Angeles County children 18-60 months of age by case-control methods. In this age group, 79 H. influenzae type b cases were identified by overlapping surveillance methods, and 221 random controls were selected by random digit dialing. Cases and controls were similar in sex, prior health, proportion attending day care, parental educational level, history of breast feeding, and proportion vaccinated with measles/mumps/rubella vaccine. The effect of H. influenzae type b vaccination was controlled in all analyses, and results of vaccine efficacy have been reported elsewhere. Cases were more likely to have a significant underlying medical condition, reside in home with more than six residents, have a lower yearly household income, have two or more smokers in the home, and to be black. Using conditional logistic regression models, the following were significant independent risk factors after adjusting for age, month of diagnosis, H. influenzae type b vaccine status, and the other factors: 1) more than two smokers in the house (odds ratio (OR) = 6.00; 95% confidence interval (CI) 1.49-24.06); 2) household size of more than six persons (OR for more than six vs. less than three persons = 3.71; 95% CI 1.10-12.60); and 3) black maternal race (OR for black vs. Hispanic = 3.47; 95% CI 1.41-8.53). We conclude that exposure to smoking in the home, living in households with more than six members, and the black race are each independently associated with an increased risk for H. influenzae type b disease in Los Angeles County children and, when combined, constitute a major reason for H. influenzae type b disease occurrence.

Age Factors↗

PubMed1992

A search for Bordetella pertussis infection in university students.

University students with persistent cough of greater than or equal to 6 days' duration were evaluated for evidence of infection with Bordetella pertussis. Of 130 students studied during a 30-month period, 34 (26%) were found to have evidence of recent infections with B. pertussis. Infection was identified by direct fluorescent antibody assay of a nasopharyngeal specimen in one student and serologically in 33 additional subjects. B. pertussis was not recovered on culture of nasopharyngeal specimens from any subjects. Students with B. pertussis infection were identified in seven of the eight 3-month periods in which students were enrolled during the 30-month investigation, suggesting an endemic rather than epidemic pattern of infection in this university population. Illnesses of students with pertussis were similar to the illnesses of students without pertussis. The findings in this study suggest that adult populations in which endemic illness occurs at a relatively constant rate may be the reservoirs for pertussis outbreaks in susceptible children. Immunization programs in the future will need to employ booster doses for adults if complete control of B. pertussis infection is our goal.

Adhesins, Bacterial↗

PubMed1991

Protective efficacy of Haemophilus influenzae type b polysaccharide and conjugate vaccines in children 18 months of age and older.

To evaluate the protective efficacy of polyribosylribitol phosphate (PRP) and polyribosylribitol phosphate-diphtheria toxoid (PRP-D) vaccines in children 18 to 59 months of age, we conducted a case-control study in Los Angeles (Calif) County between July 1, 1988, and July 31, 1989. Seventy-nine children with invasive Haemophilus influenzae type b disease 18 to 59 months of age were identified, and 212 controls were selected by random-digit telephone dialing methods. Cases and controls were stratified by age and month of disease onset of the case. Seventeen PRP vaccine failures and two PRP-D vaccine failures occurred more than 2 weeks after vaccination. The PRP vaccine was shown not to be effective (point estimate--47%; 95% confidence interval,--307% to 47%), but the PRP-D vaccine was 88% protective (95% confidence interval, 42% to 97%). Adjustment of the efficacy estimates for potential confounding variables did not change the results significantly. The PRP-D vaccine provided significantly better protection than the PRP vaccine against invasive H influenzae type b disease in this population.

Bacterial Capsules↗

PubMed1991

Apparent decreased risk of invasive bacterial disease after heterologous childhood immunization.

To investigate the possibility that there might be an increased risk of heterologous invasive bacterial disease after routine childhood immunization with measles, mumps, and rubella vaccine live; diphtheria and tetanus toxoids and pertussis vaccine; and oral poliovirus vaccine live, a case-control study was conducted within the Kaiser Permanente Northern California pediatric population. Contrary to the premise, an apparent protective effect against invasive bacterial disease was detected after all childhood vaccinations. However, when adjustment was made for frequency of well-care visits and day-care attendance, no significant relationship was seen between receipt of routine childhood immunizations and risk of invasive heterologous bacterial disease for any individual vaccine, although a statistically significant protective effect was detected within 1 or 3 months after the receipt of any vaccine. Since a decreased risk of invasive bacterial disease was also noted to be related to the receipt of routine well-child pediatric care, other preventive health care measures may be responsible for the apparent immunization protective effect.

Bacterial Infections↗

PubMed1991

DTP immunization and susceptibility to infectious diseases. Is there a relationship?

A two-part study was carried out in Alaskan Native children to evaluate the potential risk of invasive bacterial disease and the occurrence of minor illnesses after immunization with diphtheria and tetanus toxoids and whole-cell pertussis vaccine (DTP). First, a case-control comparison was performed with 186 children who had invasive Haemophilus influenzae type b or Streptococcus pneumoniae disease (cases) and 186 healthy controls matched for sex, region of residence, birth date, and number of DTP immunizations. The proportion of cases and controls immunized in the 30-day period before onset of disease for cases or reference date for controls was identical, suggesting no association with DTP immunization. In a second analysis, the occurrence of any illness, particularly infectious diseases, in 104 study subjects was compared for the period 30 days before and after 377 DTP immunizations. The rate of illness before immunization was 53%, and after immunization, 43%, again suggesting no causative effects from DTP immunization. Despite the high rates of invasive bacterial disease and nearly compete DTP immunization status in this population, no consistent relationship could be demonstrated between DTP immunization and susceptibility to infectious diseases.

Alaska↗

PubMed1989

Analyses of adverse reactions to diphtheria and tetanus toxoids and pertussis vaccine by vaccine lot, endotoxin content, pertussis vaccine potency and percentage of mouse weight gain.

We investigated the rates of local and systemic reactions following 9920 diphtheria-tetanus toxoids-pertussis immunizations from 25 lots of commercially available, United States-licensed diphtheria-tetanus toxoids-pertussis adsorbed vaccines from four manufacturers as a function of vaccine lot, endotoxin content, pertussis vaccine potency and percent of mouse weight gain. There were significant differences between the rates of reactions by lot for all local and systemic reactions except convulsions and hypotonic hyporesponsive episodes. For these latter reactions there were insufficient cases for analyses. P was less than 0.0001 for local reactions, fever, drowsiness, fretfulness, anorexia and screaming and 0.017 for vomiting. No single lot was associated with the highest or lowest rate of reactions for more than 3 of the 11 reactions. There was a significant positive association of endotoxin unit (EU) content and the percent of vaccine recipients who developed fever (P = 0.004). Fever increased in frequency from 20.6% of children immunized with vaccine lots that contained 2500 EU to 55.1% of children immunized with vaccine lots containing 40,000 EU. There were significant positive associations of all local reactions and pertussis vaccine potency (P = 0.0004), and percent of mouse weight gain (P less than 0.0001). There was also a positive association of percent mouse weight gain and persistent screaming (P = 0.001). However, for the majority of reactions there was no clinically meaningful associations between reaction rates and the biological properties of the vaccine studied.

Animals↗

PubMed1988

Relationship of pertussis immunization to the onset of neurologic disorders: a retrospective epidemiologic study.

A retrospective epidemiologic study examining the relationship of the time of onset of neurologic disorders with the time of pertussis immunization in two cohorts of children who received pertussis immunization at different ages is reported. Before April 1970, children in Denmark were vaccinated with diphtheria and tetanus toxoids with pertussis vaccine at 5, 6, 7, and 15 months of age. Since 1970, children were given monovalent pertussis vaccine at 5 and 9 weeks and at 10 months of age. A total of 554 cases of epilepsy with onset between 28 days and 24 months of age were reviewed, 286 from the 1967-1968 period and 268 from the 1972-1973 period. There was no relationship between the age of onset of epilepsy and the scheduled age of administration of pertussis vaccine. A total of 2199 children with febrile seizures were reviewed, 830 from the 1967-1968 period and 1369 from the 1972-1973 period. There was a statistical association between first febrile seizures and the scheduled age of administration of pertussis vaccine (p = 0.004). No relationship between pertussis immunization and the occurrence of central nervous system infections was noted.

Age Factors↗

PubMed1988

Relationship of pertussis immunization to the onset of epilepsy, febrile convulsions and central nervous system infections: a retrospective epidemiologic study.

A change in the pertussis immunization schedule in Denmark allowed a retrospective study examining the relationship of the time of onset of selected neurologic disorders with the time of pertussis immunization in two core cohorts of children. Records of 2,199 children with febrile seizures were reviewed and a significant association between first febrile seizures and the scheduled age of pertussis immunization was noted (p = 0.004). The occurrence of epilepsy and CNS infections did not appear to be related to the time of pertussis immunization.

Central Nervous System Diseases↗

PubMed1987

Primary cerebral lymphoma in two consortial partners afflicted with acquired immune deficiency syndrome.

Two consortial partners presented within 3 weeks of one another with signs and symptoms of neurological dysfunction. Both were found to have acquired immune deficiency syndrome (AIDS) and primary cerebral lymphoma. We found 17 case reports of primary central nervous system (CNS) lymphoma in AIDS patients. Ten of these cases were described sufficiently to enable analysis. Our 2 cases are unique in that this is the first time primary CNS lymphoma has been reported in sexual partners with AIDS. One case includes the use of magnetic resonance imaging. Both patients underwent craniotomy and received radiation therapy.

Acquired Immunodeficiency Syndrome↗

PubMed1977

Plasma prostaglandin E concentrations from birth through childhood.

The prostaglandins are synthesized in a variety of tissues and participate in an extensive number of physiologic processes. As prostaglandin concentrations have not been reported in infants and children, we measured PGE levels from birth through childhood. PGE levels in cord blood were significantly higher than those in adults. By 48 to 72 hours of age, however, they had fallen to levels that were significantly lower than those in adults. Although PGE concentrations increased with age, they remained significantly lower than did adult levels. These low levels may be related to some of the functional pecularities of the immature kidney.

Adolescent↗

PubMedDate not supplied