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Biomedical subjects

R M Jacobson

Publications and source records attributed to R M Jacobson.

48 records · Page 3Linked to original sources

Epiglottitis in adults and children in Olmsted County, Minnesota, 1976 through 1990.

OBJECTIVE: To compare the initial clinical manifestations and sequelae of epiglottitis among children and adult residents of Olmsted County, Minnesota. MATERIAL AND METHODS: We conducted a population-based retrospective cohort study of all Olmsted County residents with the diagnosis of epiglottitis during the 15-year period from Jan. 1, 1976, through Dec. 31, 1990. RESULTS: From 1976 through 1990, 41 residents (20 children and 21 adults) of Olmsted County were diagnosed with epiglottitis. (One case in an adult was first diagnosed at autopsy and was included only in the incidence rates and analysis of seasonal and secular trends.) Children had a mean annual incidence rate of 4.25 per 100,000, whereas the rate in adults was 2.18 per 100,000. The age- and sex-adjusted incidence of epiglottitis decreased during the study period from 4.94 per 100,000 during 1976 through 1980 to 2.08 per 100,000 during 1986 through 1990. No seasonal effect was detected in adults or children. At initial assessment, adults tended to have pharyngeal symptoms (sore throat and odynophagia), cervical adenopathy, and ear pain, whereas children most often had respiratory (stridor, dyspnea, and retractions) and laryngeal symptoms. Proportionately, more children than adults received artificial airway support and had associated pneumonia. One death occurred in an adult, in whom the diagnosis was made at autopsy. CONCLUSION: The incidence of epiglottitis has decreased significantly in recent years. Children and adults have considerably different initial manifestations of epiglottitis.

Adolescent↗

The influence of the HLA-DRB1*13 allele on measles vaccine response.

BACKGROUND: Measles remains a public health threat in the United States with over 50,000 cases being reported from 1989 through 1991 with continued smaller outbreaks. Measles vaccine failure is in part to blame for these large-scale outbreaks. The human leukocyte antigen (HLA) genes are important determinants of immune response to measles virus and vaccine. To examine the influence that HLA polymorphisms may have on measles vaccine antibody response, we compared the distribution of HLA-DRB1 alleles between measles vaccine nonresponders and hyper-responders. METHODS: We determined the seroprevalence of measles antibody in 881 school children immunized with measles-mumps-rubella-II at age 15 months using a whole virus IgG EIA. We performed class II HLA-DR typing by PCR with sequence specific primers (PCR-SSP) on 81 nonresponders (IgG seronegative) and 65 hyper-responders (from the upper 10th percentile of IgG levels of all subjects). We then compared the distribution of alleles between nonresponders and hyper-responders. RESULTS: The distribution of HLA-DRB1 alleles among nonresponders compared to hyper-responders was significantly different (p = 0.014). Nonresponders were significantly less likely to carry the HLA-DRB1*13 alleles than were hyper-responders (7.4% vs 16.2%;p = 0.02). Nonresponders also had an excess of HLA-DRB1*07 alleles (15.4% vs 6.2%; p = 0.015). CONCLUSIONS: The absence of HLA-DRB1*13 alleles is associated with measles vaccine nonresponse. The absence of this allele has also been associated with susceptibility to other infectious diseases. The role of this gene in the immunogenetic response to infectious diseases requires further study.

Alleles↗

Incidence of sudden infant death syndrome in Olmsted County, Minnesota: 1945 through 1992.

OBJECTIVE: To apply uniform diagnostic criteria for sudden infant death syndrome (SIDS) for an extended period for comparison of incidence rates from 1945 to 1992 in Olmsted County, Minnesota, to investigate the influence of a person-time or live birth denominator on the estimate of incidence, to calculate the proportionate mortality rate for SIDS over time, and to evaluate the accuracy of death certificates for case ascertainment and the role of interobserver variation in case classification. DESIGN: We retrospectively reviewed the autopsy results and complete medical records for all infant death from 1945 through 1992 for residents of Olmsted County, Minnesota. MATERIAL AND METHODS: Cases were identified from a computerized list of all Olmsted County deaths of infants occurring at ages 48 hours to 365 days. All resident cases were categorized as non-SIDS, possible SIDS, SIDS, or incomplete, on the basis of findings from autopsy and clinical history. Incidence rates were calculated for two different SIDS groups and with use of denominators of person-time and live births. RESULTS: For the study period, 82 cases of SIDS were identified (97% white and 3% Asian). The mean age at death was 12.5 weeks; male infants constituted 59% of cases. No significant trend in seasonal distribution was noted; 73% of deaths occurred between midnight and noon. The incidence rate, defined as SIDS definite and possible deaths per 1,000 resident live births, increased from 0.55 in 1950 through 1953 to 1.28 in 1990 through 1992. The secular trend was best described by a linear model with constant positive slope. Similar trends were observed with other definitions of incidence. During the study period, SIDS as a percentage of total infant deaths dramatically increased, ranging from 2.5 in 1950 through 1953 to 17.9 in 1990 through 1992. The death certificate diagnosis correctly predicted 72% of SIDS cases before 1970 and 100% of cases after 1970. CONCLUSION: Since 1945, the incidence of SIDS apparently has increased, although diagnostic transfer from other causes of death probably contributes to the observed trend. The comparison of live births versus person-time as denominators showed no significant difference in incidence rates. Interobserver reliability is modest for SIDS cases diagnosed before 1970 and may contribute to the variability in reported SIDS incidence rates.

Death Certificates↗

The surprisingly high acceptability of low-efficacy vaccines for otitis media: a survey of parents using hypothetical scenarios.

OBJECTIVE: To determine parental thresholds for accepting vaccines for otitis media prevention given tradeoffs of efficacy, adverse effects, and administration mode. METHOD: We interviewed 601 randomly selected parents with children 0 through 6 years of age presenting to our community pediatric clinic. For each of five hypothetical vaccines, which varied administration mode from nasal spray to two injections and adverse effects from mild to severe, parents indicated the lowest number of otitis media episodes that the vaccine had to prevent in the next 6 months for them to accept the vaccine. RESULTS: About half the parents would accept any one of the vaccines if it would prevent three or more infections in the next 6 months. When the vaccine would prevent one episode of otitis media over the next 6 months, 33% of parents would accept the medial vaccine (one injection in the thigh, with some children getting a red, sore injection site and a few having a fever of < or = 102 degrees F for one day). Seventeen percent accepted a vaccine requiring two injections (influenza vaccine-like) or having increased adverse effects (pneumococcal vaccine-like) despite the vaccine only preventing one episode of otitis media over the next 6 months. No substantial differences in these proportions were found when compared among groups by reason-for-visit, recent occurrence of otitis media, or a history of recurrent otitis media in a sibling. CONCLUSION: Many parents will accept low efficacy vaccines for otitis media prevention. Parental acceptance does not vary with the child's otitis media experience but does vary with severity of adverse effects and administration mode of the vaccine.

Child↗

Failure to reach the goal of measles elimination. Apparent paradox of measles infections in immunized persons.

BACKGROUND: Measles is the most transmissible disease known to man. During the 1980s, the number of measles cases in the United States rose dramatically. Surprisingly, 20% to 40% of these cases occurred in persons who had been appropriately immunized against measles. In response, the United States adopted a two-dose universal measles immunization program. We critically examine the effect of vaccine failure in measles occurring in immunized persons. METHODS: We performed a computerized bibliographic literature search (National Library of Medicine) for all English-language articles dealing with measles outbreaks. We limited our search to reports of US and Canadian school-based outbreaks of measles, and we spoke with experts to get estimates of vaccine failure rates. In addition, we devised a hypothetical model of a school where measles immunization rates could be varied, vaccine failure rates could be calculated, and the percentage of measles cases occurring in immunized students could be determined. RESULTS: We found 18 reports of measles outbreaks in very highly immunized school populations where 71% to 99.8% of students were immunized against measles. Despite these high rates of immunization, 30% to 100% (mean, 77%) of all measles cases in these outbreaks occurred in previously immunized students. In our hypothetical school model, after more than 95% of schoolchildren are immunized against measles, the majority of measles cases occur in appropriately immunized children. CONCLUSIONS: The apparent paradox is that as measles immunization rates rise to high levels in a population, measles becomes a disease of immunized persons. Because of the failure rate of the vaccine and the unique transmissibility of the measles virus, the currently available measles vaccine, used in a single-dose strategy, is unlikely to completely eliminate measles. The long-term success of a two-dose strategy to eliminate measles remains to be determined.

Canada↗

Estimating the predictive value of a diagnostic test. How to prevent misleading or confusing results.

The diagnostic process consists of a series of steps in which the estimated probability of particular disease is increased or decreased until either treatment can be instituted or the diagnosis excluded. The history and physical exam play an important role. If a therapeutic decision cannot confidently be made on clinical grounds alone, a diagnostic test may confirm or exclude a diagnosis or clearly indicate the need for further testing. An inappropriately chosen test or misinterpreted test result, however, may mislead the clinician and possibly harm the patient or simply be wasteful. Estimating the predictive values of a diagnostic test will help to avoid these pitfalls. This article shows the clinician a simplified way to do this.

Child↗

Intraoperative transvascular balloon catheter management for arterioureteral fistula.

An arterioureteral fistula is a rare but intriguing anomaly. Fewer than two dozen cases have been recorded, and all have relayed the extreme diagnostic and therapeutic challenges that this entity presents to the clinician. Factors contributing to the development of such a fistula include prolonged ureteral catheterization, prior pelvic vascular or urologic surgery, cancer or radiation. These patients are severely debilitated, and repair has a mortality rate in excess of 15%. Experience with such a patient is reported, as well as use of a minimally invasive approach to repair the abnormality. By using transvascular balloon occlusion of the involved iliac vessel and extra-anatomic vascular reconstruction, the significant morbidity and mortality associated with this disorder were avoided. Suspicion of an arterioureteral fistula should be increased in those at risk and treatment can be effected with this minimally invasive method.

Adenomatous Polyposis Coli↗

Oxygen as a cause of blindness in premature infants: "autopsy" of a decade of errors in clinical epidemiologic research.

Several intellectual "autopsies" have recently reviewed errors in clinical epidemiologic studies of causation, such as the original claim that amyl nitrite "poppers" caused AIDS. The current autopsy was done to determine why it took more than a decade--1942 to 1954--to end an iatrogenic epidemic in which high-dose oxygen therapy led to retrolental fibroplasia (RLF) in premature infants, blinding about 10,000 of them. The autopsy revealed a museum of diverse intellectual pathology. When first noted, RLF was regarded as neither a new disease nor a postnatal effect. In early investigations, the ophthalmologists did not establish explicit criteria for diagnosis and confused RLF with malformations previously seen in full-term infants. Because the patients were not referred until months after birth, the ophthalmologists assumed that the lesion, which resembled an embryologic structure, must have occurred prenatally. Other events suggesting a prenatal cause for RLF were its strong statistical associations with fetal anomalies, multiple gestations, and maternal infections. Although these events were also associated with prematurity, it was ignored when the RLF cases were compared with controls who were mainly full-term infants. The postnatal timing of RLF was eventually recognized when investigators did cohort studies in premature infants and found that RLF could develop in eyes that were normal at birth. As the search for a cause turned to events occurring after birth, statistical associations were produced for agents such as light, vitamins, iron, vitamin E deficiency, and hypoadrenalism. Each study had its own methodologic flaws: controls were missing for light; co-maneuvers were ignored for vitamins and iron; objective diagnosis was not used for vitamin E deficiency; and the research on hypoadrenalism contained biases in susceptibility and detection as well as problems of a competing outcome event. When the role of oxygen administration was first considered, the statistical association with RLF was stronger for vitamin- and iron-therapy than for oxygen. In addition, many investigators were dissuaded by contradictory evidence from institutions in which RLF was either absent despite high-dose oxygen or persistent despite reduced dosage. The contradictory evidence was later regarded as erroneous because of unsatisfactory delivery systems for the oxygen or failure to check the actual oxygen concentrations. An alternative explanatory hypothesis, rejecting the role of high-dose and long-duration oxygen, was the idea that RLF was due to "relative hypoxia", produced by overly rapid weaning from oxygen therapy rather than the duration of oxygen treatment itself.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Relationship of HLA-DQA1 alleles and humoral antibody following measles vaccination.

BACKGROUND: The human leukocyte antigen (HLA)-DQA1 locus is only moderately polymorphic compared to other HLA class II loci; however, we hypothesized that these polymorphisms could be important in determining the humoral antibody response to measles vaccine virus. METHODS: The seroprevalence of measles antibody was determined in 881 school children who had been immunized with MMR-II at age approximately 15 months. All subjects resided in a geographic area with no circulating measles virus. The IgG antibody levels were determined by a measles-specific whole virus enzyme immunoassay (EIA) (BioWhittaker, Walkersville, MD). Subjects who were nonresponders (IgG seronegative or equivocal) (n = 46) and hyperresponders (upper 10th percentile of IgG levels of all subjects) (n = 64) were HLA-DQA1 typed using polymerase chain reaction with sequence-specific primers (PCR-SSP). The HLA-DQA1 allele frequencies, as well as homozygosity rates, were compared between the nonresponders and hyperresponders. RESULTS: The overall allele frequency distribution of alleles between the nonresponders and hyperresponders was significantly different (P = 0.05), with nonresponders having an excess of HLA-DQA1*05 alleles (P = 0.017) and hyperresponders having an excess of HLA-DQA1*01 alleles (P = 0. 016). The homozygosity rate among nonresponders was significantly higher than among hyperresponders (23.9% vs. 9.4%, P = 0.037). CONCLUSION: HLA-DQA1 alleles have important associations with the antibody response to measles vaccine. Specifically, the carriage of the HLA-DQA1*05 alleles is associated with nonresponse and that of HLA-DQA1*01 alleles with hyperresponse. In addition, HLA-DQA1 homozygosity is significantly associated with poor antibody response to measles vaccine.

Adolescent↗

Barriers to immunization in a relatively affluent community.

BACKGROUND: Although Healthy People 2000 calls for the complete immunization of at least 90% of children by age 20 months, few communities can claim such success. We wanted to determine the parent-reported barriers associated with underimmunization of infants in a relatively affluent midwestern population. METHODS: We undertook a case-control study of a population-based sample of parents and guardians of children who were either fully immunized or underimmunized at 20 months of age in Olmsted County, Minn. RESULTS: In this study, 596 of 1,216 parents (46%) of both immunized and underimmunized children participated. Of these participants, 281 (47%) reported barriers to immunizations, but only 15 (3%) reported major barriers. Whereas the most commonly reported barriers were barriers of inconvenience (waiting too long, inconvenient office hours), only delays caused by a sick child, fear of reactions, trouble remembering an appointment, not knowing when the next shot was due, and transportation problems were significantly associated with underimmunization when controlling for demographic factors. Fear of reactions, sick child delays, and not knowing when the next shot was due had the highest attributable risk for underimmunization. Taken together, parent-reported barriers and demographic factors explained less than 30% of the underimmunization status of children. Parents' most common recommendations for improving immunization status were the use of a recall or reminder system and a single unified schedule for immunizations. CONCLUSIONS: In this relatively affluent community, barriers to immunization were commonly reported but few (fear of reactions, sick child delays, and not knowing when the next shot was due) were associated with underimmunization. The types of barriers reported were similar to those reported in other communities, but unlike many populations studied, cost was not reported as an important barrier.

Case-Control Studies↗