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Biomedical subjects

A T Berg

Publications and source records attributed to A T Berg.

At least 73 records · Page 4Linked to original sources
PubMed1992

A prospective study of recurrent febrile seizures.

BACKGROUND: Febrile seizures occur in about 2 to 4 percent of all children, approximately one third of whom will have recurrent febrile seizures. Little is known about predictors of recurrence. METHODS: In this prospective study, we identified 347 children (1 month to 10 years of age) who presented with a first febrile seizure at one of four pediatric emergency departments. Information about these children was collected from medical records and interviews with the parents, and the children were followed for a median of 20 months to ascertain whether febrile seizures recurred. RESULTS: Recurrent febrile seizures occurred in 94 of the 347 children (27 percent) with a cumulative risk of 25 percent at one year and 30 percent at two years. The duration of fever before the initial seizure was associated with the risk of recurrence at one year: for fever lasting less than 1 hour, the risk of recurrence was 44 percent; for fever lasting 1 to 24 hours, 23 percent; and for fever lasting more than 24 hours, 13 percent (P less than 0.001). With each degree of increase in temperature (in degrees Fahrenheit), from 101 degrees F (38.3 degrees C) to greater than or equal to 105 degrees F (40.6 degrees C), the risk of recurrence at one year declined, from 35 percent to 30, 26, 20, and 13 percent (P for trend = 0.024). An age of less than 18 months and a family history of febrile seizures were also associated with an increased risk of recurrence. A family history of epilepsy, complex febrile seizures, and neurodevelopmental abnormalities did not increase the risk of recurrent febrile seizures. CONCLUSIONS: A shorter duration of fever before the initial febrile seizure and a lower temperature are associated with an increased risk of recurrence in children who have febrile seizures.

Age Factors↗
PubMed1992

Febrile seizures and epilepsy: the contributions of epidemiology.

In the past, febrile seizures were considered to be a sign of epilepsy, a disorder characterised by recurrent unprovoked seizures. Currently, febrile seizures are considered to be a benign seizure syndrome that is distinct from epilepsy. This distinction has been possible largely because of the epidemiological evidence which is presented here in the form of a two-part argument. If febrile seizures are epilepsy one might expect that: (1) following a first febrile seizure, the risk of a second febrile seizure should be similar to the risk of an unprovoked seizure (in fact, the risk of a recurrent febrile seizure is approximately 34%, whereas the risk of an unprovoked seizure after having had a febrile seizure is approximately 2% to 3%); (2) the factors that predict recurrent febrile seizures should also predict subsequent unprovoked seizures. From the available literature, young age at the time of the first febrile seizure and a family history of febrile seizures predict recurrent febrile seizures, but do not predict subsequent unprovoked seizures. By contrast, a family history of epilepsy, complex febrile seizures and neurological abnormality are associated with an increased risk of subsequent epilepsy but are not consistently associated with the risk of a recurrent febrile seizure.

Age Factors↗
PubMed1991

The protective efficacy of polyvalent pneumococcal polysaccharide vaccine.

BACKGROUND: Although the protective efficacy of pneumococcal polysaccharide vaccine has been demonstrated in randomized trials in young African gold miners, there has been controversy about its efficacy in older Americans at risk for serious pneumococcal infections. To assess the vaccine's protective efficacy against invasive pneumococcal infections, we conducted a hospital-based case-control study of the efficacy of pneumococcal vaccine in adults with a condition recognized to be an indication for receiving the vaccine. METHODS: From 1984 to 1990, adults in whom Streptococcus pneumoniae was isolated from any normally sterile site were identified by prospective surveillance in the microbiology laboratories of 11 large hospitals; those with an indication for pneumococcal vaccine were enrolled as case patients. For each case patient, one control was matched according to age, underlying illness, and site of hospitalization. We contacted all providers of medical care to ascertain each subject's history of immunization with pneumococcal vaccine. Isolates of S. pneumoniae were serotyped by an investigator unaware of the subject's vaccination history. RESULTS: Thirteen percent of the 1,054 case patients and 20 percent of the 1,054 matched controls had received pneumococcal vaccine (P less than 0.001). When vaccine was given in either its 14-valent or its 23-valent form, its aggregate protective efficacy (calculated as a percentage: 1 minus the odds ratio of having been vaccinated times 100) against infections caused by the serotypes represented in the vaccine was 56 percent (95 percent confidence interval, 42 percent to 67 percent; P less than 0.00001) for all 983 patients infected with a serotype represented in the vaccine, 61 percent for a subgroup of 808 immunocompetent patients (95 percent confidence interval, 47 percent to 72 percent; P less than 0.00001), and 21 percent for a subgroup of 175 immunocompromised patients (95 percent confidence interval, -55 percent to 60 percent; P = 0.48). The vaccine was not efficacious against infections caused by serotypes not represented in the vaccine (protective efficacy, -73 percent; 95 percent confidence interval, -263 percent to 18 percent; P = 0.15). CONCLUSIONS: Polyvalent pneumococcal vaccine is efficacious in preventing invasive pneumococcal infections in immunocompetent patients with indications for its administration. This vaccine should be used more widely.

Adolescent↗
PubMed1991

Menstrual cycle length and the calculation of gestational age.

The method of estimating gestational age that is most commonly employed by epidemiologists calculates age as the time between the first day of the last menstrual period and the date of birth. The method assumes an invariant 28-day menstrual cycle with ovulation occurring at midcycle. Data from 5,688 mothers and their infants who were enrolled in the Boston sector of the National Collaborative Perinatal Project from 1959 through 1965 were used to study whether this is a valid assumption by examination of the association between gestational age and cycle length. In addition, two methods for adjusting gestational age for cycle length were explored: 1) the Ogino-Knaus adjustment which assumes that the postovulatory phase of the menstrual cycle is a constant 14 days long, and 2) an empirically derived approach. Cycle length was grouped into five categories. With the last menstrual period method, the proportion of postterm (more than 42 weeks) and postdate (more than 40 weeks) births increased with longer cycle lengths (from 0 to 14.6% for postterm and from 21.0 to 53.7% for postdate). With the Ogino-Knaus correction, the trend was weaker and in the opposite direction (10.5 to 2.4% for postterm and 57.9 to 22.0% for postdate). With the empirically derived method, these trends were virtually eliminated (5.3 to 9.8% for postterm and 36.7 to 36.5% for postdate). The results suggest that the previously reported tendency for the last menstrual period method to yield a high proportion of postdate and postterm deliveries may, in part, be due to misclassification of gestational age in women with long menstrual cycles. The Ogino-Knaus method appears to overcorrect for cycle length. The empirically derived method needs further validation; however, it does suggest potential directions to be explored.

Bias↗
PubMed1991

Group day care and the risk of serious infectious illnesses.

Group day care attendance has been associated with an increased risk of infectious illnesses. With the exception of illnesses caused by Haemophilus influenzae type b (H. influenzae) and Neisseria Meningitidis (N. meningitidis), most studies have examined relatively mild illnesses. A matched case-control study was conducted to study the association between group day care attendance and serious infectious illnesses (requiring hospitalization). Cases were children aged 3 months to 59 months hospitalized for an infectious illness at Yale-New Haven Hospital from June 1984 through November 1986. Each case was matched to a control by date of birth and regular pediatrician, and their parents were interviewed. Data from 193 matched pairs were analyzed using conditional logistic regression. The matched odds ratio (OR) for the association between group day care attendance and serious infectious illness was 1.39 (95% confidence interval (CI) 0.87-2.20). For pairs in which the case had an H. influenzae infection (n = 46), the odds ratio was 8.00 (95% CI 1.00-63.85), and for N. meningitidis (n = 9) the odds ratio was 2.00 (95% CI 0.39-10.27). In the remaining 138 pairs, the odds ratio was 1.27 (95% CI 0.76-2.12). In infants less than 12 months of age (n = 64) the odds ratio for group day care and illnesses (excluding H. influenzae and N. meningitidis) was 1.66 (95% CI 0.73-3.80) and it was 1.06 (95% CI 0.55-2.05) for older children (n = 74). The data suggested an association between day care attendance and invasive bacterial infections other than H. influenza and N. meningitidis, OR = 2.00 (95% CI 0.81-4.94) but not for local bacterial infections, OR = 1.00 (95% CI 0.25-4.00) or infections of presumed viral etiology, OR = 1.00 (95% CI 0.49-2.05). Important predictors of serious infections (excluding H. influenzae and N. meningitidis) were passive smoking (OR = 3.96, 95% CI 2.16-7.24) and sharing a bedroom (OR = 2.31, 95% CI 1.23-4.33). These findings do not suggest that group day care attendance poses a large risk of serious infections (other than H. influenzae or N. meningitidis) to young children; however, at least one preventable factor, passive smoking, may.

Child↗
PubMed1991

The risk of seizure recurrence following a first unprovoked seizure: a quantitative review.

Knowledge of the recurrence risk following a first unprovoked seizure and the predictors of that risk are necessary for rational treatment decisions. Published estimates of recurrence risk range from 23% to 71%. In a meta-analysis of 16 reports, three methodologic factors explained much of the reported variation: (1) study inclusion criteria, ie, whether patients were enrolled at the time of their first seizure or if patients with prior seizures were included; (2) retrospective versus prospective ascertainment of patients; (3) the interval between the first seizure and the time at which risk was assessed. The average recurrence risk across the 16 studies was 51%. The risk was 40% and 52% in prospective and retrospective studies that employed first-seizure methods and 67% in non-first seizure studies. At or near 2 years following the first seizure, the recurrence risk was 36% and 47% in prospective and retrospective first-seizure studies. The distribution of prognostic factors was also important. Seizure etiology and the EEG were the strongest predictors of recurrence distinguishing between patient subgroups, with recurrence risks as low as 24% and as high as 65%. Partial seizures were associated with an increased recurrence risk, but not consistently. There is considerable agreement among studies concerning the recurrence risk following a first seizure, and much of the discrepancies among studies can be explained by differences in study methods and distributions of important prognostic factors.

Age Factors↗
PubMed1990

Predictors of recurrent febrile seizures: a metaanalytic review.

The 1980 National Institutes of Health Consensus Development Conference on Febrile Seizures identified five circumstances in which it might be appropriate to consider anticonvulsant prophylaxis after a first febrile seizure: (1) a focal or prolonged seizure, (2) neurologic abnormalities, (3) afebrile seizures in a first-degree relative, (4) age less than 1 year, and (5) multiple seizures occurring within 24 hours. We performed a metaanalysis of 14 published reports to evaluate the strength of association between each of these indications and recurrent febrile seizures. Young age at onset (less than or equal to 1 year) and a family history of febrile seizures (not listed in the recommendations) each distinguished between groups with approximately a 30% versus a 50% risk of recurrence. Family history of afebrile seizures was not consistently associated with an increased risk. Focal, prolonged, and multiple seizures were associated with only a small increment in risk of recurrence. The data were not adequate to assess the risk associated with neurologic abnormalities. By considering children with combinations of risk factors, some studies were able to distinguish between groups with very low and very high recurrence risks. Only age at onset was consistently predictive of having more than one recurrence. These results suggest that the great majority of children who have a febrile seizure do not need anticonvulsant treatment even if one of the factors listed in the Consensus Statement is present, and that the rationale and indications for treating febrile seizures need to be reconsidered.

Age Factors↗
PubMed1990

The effect of right atrial catheters on infectious complications of chemotherapy in children.

Rates of infections and catheter complications in children with right atrial catheters (RACs) receiving chemotherapy were compared with those without RACs in a retrospective cohort study. One hundred sixty-five children presenting to Yale-New Haven Hospital with a malignancy diagnosed between January 1, 1981 and December 31, 1985 were followed through June 30, 1986 for the number of treatment-related complications resulting in hospitalization. The time on therapy totaled 80,089 person-days that were divided into 510 periods of observation defined by the presence or absence of a RAC, disease status (remission, partial remission, or relapse), intensity of chemotherapy (using a 0 to 4 scale), and use of radiation therapy. Children with RACs experienced markedly higher rates of sepsis (14-fold higher, P less than .0001) and catheter-site infection or other catheter complications requiring hospitalization (both greater than 30-fold higher, P less than .0001). These effects persisted after controlling for other risk factors, ie, disease status, chemotherapy intensity, and age. Children with RACs also had higher rates of fever and neutropenia and other infections requiring hospitalization that were more strongly influenced by the other risk factors. The association of RACs with sepsis, fever and neutropenia, and days hospitalized for treatment-related complications was assessed using multivariable analysis methods to control for disease status, intensity of chemotherapy, radiation therapy, type of cancer, age, and sex. The presence of a RAC (rate ratio [RR], 6.39; P less than .0001) and the disease status (RR, 2.45; P = .0004) were the only factors that predicted sepsis. Fever and neutropenia rates were most influenced by chemotherapy intensity (RR, 2.31; P = .0001) and age (RR, 0.94; P = .013 per year of age) and less by the presence of a RAC (RR, 1.56; P = .053). Controlling for other risk factors, children with RACs experienced a 6.4-times higher rate of sepsis and spent an average of 15.4 more days per year in the hospital for treatment-related complications.

Adolescent↗
PubMed1990

Protective efficacy of Haemophilus influenzae type b polysaccharide vaccine.

There has been uncertainty and controversy about the protective efficacy of Haemophilus influenzae type b polysaccharide vaccine almost since it first was licensed in the United States. This article will briefly review the available epidemiologic data about the protective efficacy of this vaccine in children with no recognized underlying illnesses. H influenzae type b polysaccharide vaccine was licensed in the United States in April 1985, based on the results of a randomized clinical trial that was conducted in Finland. That study indicated that the vaccine's protective efficacy was 90% against invasive disease caused by H influenzae type b in children 18 to 71 months of age. Authorities recommended that all children receive the vaccine at 2 years of age and that it be administered to children up to the age of 60 months. The Immunization Practices Advisory Committee also recommended that children at increased risk (such as those who attend group day care) receive the vaccine at 18 months and again at 24 months of age because of its inconsistent immunogenicity when administered to 18-month-old children. Soon after its licensure, however, reports of vaccine failures began to appear. In some instances the vaccine failure could be attributed to an identifiable immune deficiency. However, Granoff et al reported 54 apparently normal children who had received the H influenzae type b polysaccharide vaccine but subsequently developed invasive disease caused by H influenzae type b. The majority of these children had normal serum concentrations of total immunoglobulins, IgG2, hemolytic complement, and antibody to tetanus toxoid (a T-cell-dependent antigen).(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Capsules↗
PubMed1990

Risk of seizure recurrence following a first unprovoked seizure in childhood: a prospective study.

In a prospective study, 283 children who presented with a first unprovoked seizure were followed for a mean of 30 months from the time of first seizure. Subsequent seizures were experienced by 101 children (36%). The cumulative risk of seizure recurrence for the entire study group was 26% at 12 months, 36% at 24 months, 40% at 36 months, and 42% at 48 months. The cumulative risk of recurrence in the 47 children with a remote symptomatic first seizure was 37%, 53%, and 60% at 12, 24, and 36 months, respectively, compared with a cumulative risk of 24%, 33%, and 36% at 12, 24, and 36 months, respectively, in the 236 children who had had an idiopathic first seizure (P less than .01). In children with an idiopathic first seizure, the electroencephalogram was the most important predictor of recurrence. The cumulative risk of recurrence in the 81 children with abnormal electroencephalograms was 41%, 54%, and 56% at 12, 24 and 36 months, respectively, but only 15%, 23%, and 26% at 12, 24, and 36 months, respectively, in the 138 children with normal electroencephalograms (P less than .001). A history of epilepsy in a first-degree relative was a significant risk factor only in idiopathic cases with abnormal electroencephalograms. In children with a remote symptomatic first seizure, either a history of prior febrile seizures or the occurrence of a partial seizure were significant predictors of recurrence. Age at first seizure and duration of seizure did not affect recurrence risk in either the idiopathic or remote symptomatic group. A total of 84% of the children were not treated with antiepileptic drugs or were treated for less than 2 weeks. Only 9% were treated for longer than 3 months. Treatment did not affect the risk of recurrence. The results suggest that, even without treatment, the majority of children with a first unprovoked seizure will not experiment a recurrence. Children with an idiopathic first seizure and a normal electroencephalogram have a particularly favorable prognosis.

Adolescent↗
PubMed1989

Indices of fetal growth-retardation, perinatal hypoxia-related factors and childhood neurological morbidity.

Data from seven-year-old children (N = 4535) who were enrolled prenatally during the 1960s and born at term in the Boston sector of the National Collaborative Perinatal Project (NCPP) have been used to study the association of 7-year neurological morbidity with symmetric and asymmetric intrauterine growth-retardation (IUGR), head circumference at birth, and perinatal hypoxia-related factors (PHRF). In the absence of hypoxia-related factors, symmetric and asymmetric IUGR children were not at higher risk for neurological morbidity compared to non-IUGR children. In the presence of perinatal hypoxia-related factors, IUGR children were more likely to be neurologically abnormal compared to non-IUGR children, and the more severe form of IUGR (symmetric) appeared to be associated with a slightly higher risk than was the asymmetric form. Small head circumference was associated with increased risk of neurological abnormality regardless of the presence of PHRF. Potential metabolic and neurodevelopmental explanations for these findings are discussed.

Cephalometry↗
PubMed1989

The immunogenicity of Hemophilus influenzae type B polysaccharide-Neisseria meningitidis group B outer membrane protein complex vaccine in infants and young children.

Hemophilus influenzae type b polysaccharide-Neisseria meningitidis group B outer membrane protein complex vaccine was administered in a single dose to 38 children ages 24-53 mo (group 1) and to 78 children ages 12-23 mo (group 2) and in two doses to 84 children ages 2-11 mo (group 3). The geometric mean concentration of the capsular antibody before and after the vaccine regimen, respectively, were 0.35 microgram/ml and 12.59 micrograms/ml in group 1, 0.18 microgram/ml and 4.79 microgram/ml in group 2, and 0.15 microgram/ml and 3.80 micrograms/ml in group 3. After completing the vaccine regimen, concentrations of capsular antibody were greater than or equal to 0.15 microgram/ml in 199 (99.5%) of the 200 children and greater than or equal to 1.0 microgram/ml in 168 (84%) of the children. There were no serious and few minor adverse reactions to the vaccine. This vaccine is immunogenic in infants and young children.

Antibodies, Bacterial↗
PubMed1988

Childhood neurological morbidity and its association with gestational age, intrauterine growth retardation and perinatal stress.

Data from 7-year-old children (n = 5363) enrolled prenatally during the 1960s in the Boston sector of the National Collaborative Perinatal Project (NCPP) have been used to study the associations of abnormal neurological findings at 7 years of age with gestational age, intrauterine growth-retardation (IUGR) and hypoxia-related perinatal stress. Among infants without perinatal stress, pre-term infants were at higher risk of abnormal neurological findings at 7 years than were term and post-term infants. IUGR infants, in the absence of stress, were not at any increased risk relative to non-IUGR infants. The odds ratio associated with perinatal stress increased with gestational age and was greater in the IUGR than in the non-IUGR infants.

Child↗
PubMed1986

Does breast-feeding protect against infections in infants less than 3 months of age?

To determine whether breast-feeding protects infants from infections, a case-control study was conducted. The cases were previously healthy children who were admitted to Yale-New Haven Hospital for an infectious illness at or before 90 days of age. The controls were chosen from the log of births and matched to the cases for five important demographic variables. In addition, logistic regression models were used to adjust the results for other potential confounders. To minimize the potential surveillance bias that might occur if formula-fed and breast-fed infants with the same degree of illness have a different probability of being hospitalized, the case-control pairs were stratified by the severity of the medical condition of the case at the time of hospitalization. For the 281 case-control pairs, the matched odds ratio was .50 (95% confidence interval .32, .77; P less than .005), which indicates that breast-feeding is protective against infections. However, this apparent protective effect was diminished substantially when the data were stratified according to the severity of illness: the matched odds ratio for the 164 infants with serious illnesses was .79 (.47, 1.32; P less than .50), and for the 117 infants with mild illnesses it was .17 (.03, .44; P less than .001). These stratified results suggest that breast-feeding protects infants from hospitalization rather than from infections. Failure to consider the problem of surveillance bias may lead to erroneous conclusions about the protective effect of breast-feeding.

Bacterial Infections↗
PubMed1982

Cell death in the mammalian visual system during normal development: II. Superior colliculus.

Degenerating cells may be observed with light microscopy in the hamster superior colliculus during early postnatal development. In the superficial gray layer and stratum opticum, 1.8 degenerating cells for each 1,000 live cells could be seen on the first postnatal day. This rate increased to 5.6 degenerating cells per 1,000 live cells by postnatal day 8. The rate of cell degeneration was consistently elevated at the medial, lateral, and caudal margins of the superficial gray layer relative to the center. In the intermediate and deep gray layers, the rate of cell death was consistently higher, starting at three degenerating cells per 1,000 on postnatal day 5, and declining to 4.7 per 1,000 by postnatal day 8. In contrast to the superficial gray layer, the number of degenerating cells in the central versus peripheral segments of the intermediate and deep gray layers was quite similar. Although the rate of observable degeneration is low, the likely rapid clearance of degenerating cell debris indicates a substantial loss of cells from the midbrain tectum in early development. The time course of observable degeneration, the amount, and the distribution of degenerating cells are quite similar in the tectum, and its major innervating structure, the retina.

Age Factors↗
PubMed1980

A neuroethological approach to hamster vision.

The contributions of the midbrain optic tectum to visuomotor behaviors likely to be important to hamsters in the wild were studied, including aperture detection, insect catching, and barrier avoidance. Following tectal undercuts, hamsters ceased to make direct approaches to apertures in the posterior 180 degrees of the visual field; this appeared to be mediated by a loss of exploratory or scanning head movements. Reorientation to and pursuit of crickets jumping out of grasp into the visual periphery was impaired, though initial approach to them was not. Barrier avoidance was unaffected by tectal undercuts. This pattern is similar to the contribution of the frog and toad optic tectum to analogous visuomotor tasks. The contribution of the tectum to searching and scanning in the hamster is an extension of the basic orienting capabilities dependent on optic tectum in anurans.

Animals↗