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Biomedical subjects

J H Ellenberg

Publications and source records attributed to J H Ellenberg.

65 records · Page 4Linked to original sources
PubMed1976

Predictors of epilepsy in children who have experienced febrile seizures.

We examined the frequency of development of afebrile seizures in 1706 children who had experienced at least one febrile seizure and were followed to the age of seven years. Epilepsy developed by seven years of age in 20 per 1000 (2 per cent), and another 10 per 1000 had at least one afebrile seizure that did not meet our definition of epilepsy. In children whose neurologic or developmental status was suspect or abnormal before any seizure and whose first seizure was complex (longer than 15 minutes, multiple or focal) epilepsy developed at a rate 18 times higher than in children with no febrile seizures (92 vs. 5 per 1000; P less than 0.001). In the largest group with febrile seizures, those previously normal with noncomplex first febrile seizures, epilepsy developed in 11 per 1000; this rate, although moderate, was greater than that for children with no febrile seizures (P = 0.027). Prior neurologic and developmental status and characteristics of the first febrile seizure are important predictors of epilepsy after febrile seizures.

Age Factors↗
PubMed1976

Randomized clinical trials. Perspectives on some recent ideas.

In spite of the controversy over the role of randomized clinical trials in medical research, the rationale underlying such trials remains persuasive as compared to recent suggestions for alternative non-randomized studies such as those relying on the use of historical controls and adjustment technics. Others have suggested that recent statistical innovations for improving clinical trials, including adaptive allocation of treatment to patients and sequential stopping procedures, are underutilized. These innovations, though theoretically interesting, are not easily adapted to large-scale, complex medical trials in which there may be multiple end points and delayed response times. Ethical considerations suggest that randomized trials are more suitable than uncontrolled experimentation in protecting the interests of patients. Randomized clinical trials remain the most reliable method for evaluating the efficacy of therapies.

Biometry↗
PubMed1976

Nutritional studies in the pregnant rhesus monkey--the effect of protein-calorie or protein deprivation on growth of the fetal brain.

Twenty four pregnant nulliparous rhesus monkeys were distributed in three groups. While pregnant, the mothers were fed a diet, adequate in mineral and vitamins, that afforded 4.2 g protein and 100 cal; 1.2 g protein and 100 cal; or 1.2 g protein and 50 cal per kg per day. The fetuses were taken by cesarian section at 156 days gestation (term = 165 days) and the cerebrum and cerebellum were subsequently analysed chemically to assess composition and growth. Analyses revealed no statistically significant changes in protein, DNA, RNA, cholesterol, phospholipid, water, or chloride space of either tissue. The zinc concentration per gram of cerebral tissue or protein was significantly elevated in the low protein low calorie group. These results indicate that the brain of the fetus of this primate is protected during frank protein-calorie restriction of the mother. Moreover it is during this time that the major part of brain development takes place. It is argued that the differences observed after maternal restriction of protein and/or calories in subprimate mammals are not necessarily applicable to the human situation.

Animals↗
PubMed1976

A preliminary report on investigation of oncogenic potential of herpes simplex virus type 2 in Cebus monkeys.

A total of 301 female and 133 male Cebus monkeys have been placed under study during a 3-year period. Females are inoculated intradermally into the cervix every 6 months; 225 receive virus and 76 receive control material. More than 50% of the animals were infected on primary inoculation, and a similar percentage was foundon the 1st reinoculation. Males are housed with females at 1:1 to 1:3 ratios. Eighteen % of the males exposed to virus-inoculated females have become infected. To date, a total of 55 pregnancies have produced 14 live births and 8 abortions. The remaining 33 animals are still pregnant. No neonatal herpes simplex virus type 2 infections have been identified. Cytological changes of mild (atypia) to moderate (dysplasia) anaplasia have persisted for 12 to 32 months in 13 herpes simplex virus type 2-infected females. These animals received their 1st inoculation 14 to 50 months ago. Persistent anaplasia has not been found in control animals.

Animals↗
PubMed1976

Testing for a single outlier from a general linear regression.

Several authors have considered the problem of detection of outliers from the general linear model Y = Xbeta + mu. Ellenberg [1973] among others, has advocated use of a detection method which involves examination of the set of internally standardized least squares residuals. Mickey [1974] and Snedecor and Cochran [1968], apparently concerned about the usefulness of an outlier detection method which is based on residual estimates that themselves are biassed by the presence of the outlier, have proposed two other alternatives. It is shown that the three approaches are exactly equivalent. A detection procedure is described which uses as its test statistic the maximum of the internally standardized least squares residuals, and upper and lower bounds for the percentage points of the test statistic are given by Bonferroni inequalities. The computations required to obtain these approximate percentage points are illustrated in a numerical example. Finally, a brief simulation study of the performance of the procedure illustrates that the power of the test can be influenced by the position of the outlier vis-a-vis the structure of the design matrix X.

Mathematics↗
PubMedDate not supplied

Selection bias in observational and experimental studies.

There has been a heightened awareness of the dangers of selection bias over the past two decades. Certainly coverage in statistical and 'statistics for medicine', and epidemiology textbooks have allocated pages to warn investigators and readers of investigations to be aware of its presence. The scientific community has not, however, yet accepted the necessity for critical assessment of the method of sample selection in the planning and execution of studies as a fundamental underpinning of observational and experimental studies. To wit, we are faced with a plethora of research studies receiving funding, being published in peer-reviewed journals and influencing future studies, that may be reporting entirely spurious associations. It is the intent of this paper to present examples of selection bias in a variety of areas which have resulted in misleading or entirely incorrect results. We hope to help make such research scientifically 'politically incorrect' to the degree that the scientific community 'just says no' to such studies, either proposed or reported.

Clinical Trials as Topic↗
PubMedDate not supplied

Does phenobarbital used for febrile seizures cause sleep disturbances?

The effect of phenobarbital on total sleep time, night awakenings, and lengthy awakenings was examined as part of a randomized trial of children with febrile seizures; information about sleep patterns was gathered by parental observation. Children were between ages 8-36 months at enrollment and were examined subsequently for 2 1/2 years. Night awakenings were not more common in children assigned to phenobarbital except for those who were poor sleepers at the beginning of the study. Total sleep time was no different in children assigned to phenobarbital than in those assigned to placebo. It is concluded that sleep problems reported in most young children with febrile seizures treated with phenobarbital did not exceed those reported in children treated with placebo, but a subset of predisposed children did experience an increase in night awakenings.

Child, Preschool↗
PubMedDate not supplied

Febrile seizures: clinical characteristics and initial EEG.

We examined the relationship between clinical characteristics and EEG classification in all children with febrile seizures examined at the University Pediatric Clinic, Skopje, Yugoslavia between 1982 and 1984. This is the only facility in Macedonia providing EEG or neurologic consultation for children. EEGs were classified as paroxysmally abnormal if they contained spikes, sharp waves, or spike-wave complexes considered abnormal for age. In all, 22% of the 676 children had an abnormal initial EEG. The most common basis for classification as abnormal was spike-wave complexes greater than 3 Hz; the next most common basis was the presence of spikes. Birth weight, gender, accompanying illness, and family history of seizures, and whether the index seizure was single or multiple were not associated with differences in rate of abnormal EEG. Clinically focal index seizures and longer duration were associated with EEG abnormality. Number of previous febrile seizures was associated with an increasing rate of EEG abnormality, from 18% in children with no previous seizures to 63% in those with four or more previous seizures. Age at EEG was linearly related to likelihood of paroxysmal EEG abnormality, both for the total cohort and for the 376 children with no previous seizures. In the total cohort, logistic regression identified leading predictors of abnormal initial EEG to be older age, number of previous febrile seizures, preexisting motor abnormality, and focal seizures. For children with a first febrile seizure, leading predictors were focal seizure, older age, and preexisting motor abnormality.

Adolescent↗