Targeting childhood obesity in schools: an examination of the stability and utility of the value added index.

BACKGROUND: High rates of childhood obesity and overweight have promoted interest in school-based interventions. As a way to identify schools with high unexpected prevalence of obesity and the greatest need, Procter and associates developed a 'Value Added Index' (VAI). It compares rates of obesity in entry level and advanced students in elementary schools, quantifying the extent to which rates for advanced students are higher than what would be expected given entry level rates and socio-demographic characteristics. METHODS: This paper replicates their analysis using data over a 4 year time span from 17 schools in the western United States. Our analysis compared results obtained with the relatively complicated mixed-model approach, which was used by Procter and associates, and a more simple linear regression, which could be easily used by local school officials. Results were also compared across the 4 years for which data were available. RESULTS: Identical results were found when the two methods were compared. There was little stability in the rank ordering of schools, based on the VAI, from 1 year to another. CONCLUSIONS: Our results cast doubts on the utility of the VAI for policy makers and suggest policy makers consider a universalistic, rather than targeted, approach to interventions.

Effect of docosahexaenoic acid content of maternal diet on auditory brainstem conduction times in rat pups.

Previous studies of dietary docosahexaenoic acid (DHA; 22:6n-3) effects on neurodevelopment have focused mainly on effects on the visual system; these studies may be confounded by effects on the retina rather than on neural pathways. Auditory brainstem conduction times (ABCTs) provide an alternate measure of central neural development. We conducted a dose-response study in which ABCTs were measured in pups whose dams were fed diets containing one of three levels of DHA (2, 4 or 6% of total fatty acids) from a single cell oil. Diets were fed during pregnancy and lactation, and pups were randomly cross-fostered on postnatal day 3 to minimize litter effects. ABCTs showed a dose-response effect, with higher levels of dietary DHA being associated with longer conduction times on postnatal day 31 (p < 0.05). Higher dietary DHA was reflected in pup cerebrums collected on postnatal days 3 and 31, and levels of arachidonic acid (AA, 20:4n-6) were inversely related to levels of DHA. This study demonstrated that the auditory brainstem response is sensitive for identifying effects of diet on neurodevelopment, and that supplementing the maternal diet with high levels of DHA may negatively impact development of the central auditory system of offspring.

The enduring effects of cohort characteristics on age-specific homicide rates, 1960-1995.

In the past decade, young people in the United States have been two to three times more likely than in the two previous decades to commit homicides, while those 25 years and older have been less likely to commit homicides than were members of their age groups in the earlier time period. These changes in youth homicide rates are associated with two cohort characteristics that are theoretically linked to criminality: relative size of cohorts and the percentage of cohort member born to unwed mothers. These effects persist throughout the life span, are independent of age and historical period, and can explain fluctuations in homicide arrest rates before the recent upturn.

Maternal diet fatty acid composition affects neurodevelopment in rat pups.

The effect of pre- and postnatal maternal dietary fatty acid composition on neurodevelopment in rat pups was studied. Timed pregnant dams were fed, beginning on d 2 of gestation and throughout lactation, either nonpurified diet (reference) or a purified diet whose fat source (22% of energy) was either corn oil or menhaden fish oil. On postnatal d 3, pups were randomly cross-fostered among dams of the same diet group and culled to 10 pups per dam. Milk was removed from stomachs of culled pups for fatty acid analyses. From postnatal d 4 to 30, pups were assessed daily for the appearance of neurodevelopmental reflexes. Auditory brainstem conduction times were measured on postnatal d 23 and 29. Pups were killed on postnatal d 30, and cerebrums were removed for fatty acid analyses. The fatty acid composition of maternal milk and pup cerebrums reflected maternal diet with higher levels of (n-3) and (n-6) fatty acids in the fish oil and corn oil groups, respectively. The time of appearance of auditory startle was significantly delayed (P = 0.004), and auditory brainstem conduction times on postnatal d 23 and 29 were significantly longer in pups of the fish oil- than corn oil-fed dams (P

Transient elevation of threshold of the neonatal auditory brain stem response.

Auditory brain stem responses (ABRs) of 33 high risk, full term or near term newborns with transient elevation of ABR threshold (transient group) were compared with those of normal infants (normal group) and high-risk infants with known conductive (conductive group) and known sensorineural hearing loss (sensorineural group). ABRs of infants in the transient group initially were not significantly different from those of the conductive group in terms of wave I latency, wave V latency, and the slope of the latency-intensity (L-l) function of wave V. In infants with transient unilateral threshold elevation, significantly shorter interpeak latencies were recorded in the affected ear than in the ear that passed. This finding has been previously described in infants with conductive disorders. On follow-up, ABRs in the transient group closely resembled those of the normal group with respect to the same measures. Otologic histories in the transient group were unremarkable in the majority of cases. Increased slope of the L-l function in infants with confirmed conductive disorders was an unexpected finding. Previous studies of patients with conductive loss had not revealed a significant deviation from normal for this measure. An age interaction for the effect might explain the discrepancy between this and previous studies.

Genetic control of capsid length in bacteriophage T4: DNA sequence analysis of petite and petite/giant mutants.

The T4 gene 23 product (gp23) encodes the major structural protein of the mature capsid. Mutations in this gene have been described which disrupt the normal length-determining mechanism (A.H. Doermann, F.A. Eiserling, and L. Boehner, J. Virol. 12:374-385, 1973). Mutants which produce high levels of petite and giant phage (ptg) are restricted to three tight clusters in gene 23 (A.H. Doermann, A. Pao, and P. Jackson, J. Virol. 61:2823-2827, 1987). Twenty-six of these ptg mutations were cloned, and their DNA sequence alterations were determined. Each member of this set of ptg mutants arose from a single mutation, and the set defined 10 different sites at which ptg mutations can occur in gene 23. Two petite (pt) mutations in gene 23 (pt21-34 and ptE920g), which produce high frequencies of petite particles but no giants, were also sequenced. Both pt21-34 and ptE920g were shown to include multiple mutations. The phenotypes attributed to both pt and ptg mutations are discussed relative to the mechanism of capsid morphogenesis. A site-directed mutation (SD-1E) was created at the ptgNg191 site, and its phenotypic consequences were examined. Plaque morphology revertants arising from a gene 23 mutant derivative of pt21-34 and from SD-1E were isolated. A preliminary mapping of the mutation(s) responsible for their revertant phenotypes suggested that both intra- and extragenic suppressors of the petite phenotype can be isolated by this method.

Nucleotide sequence of bacteriophage T4 gene 23 and the amino acid sequence of its product.

We have determined the nucleotide sequence of gene 23 of bacteriophage T4 by the methods of Maxam and Gilbert and of Sanger. The identities of approximately 80% of the amino acid residues of the major capsid protein which is encoded by gene 23 were determined additionally by Edman degradation of the intact protein and its peptides. Fifteen gene 23 amber mutation sites have been located within the sequence, and the 3' transcription termination site for genes 21, 22 and 23 has been identified.

Clinically useful applications of evoked potentials in adult neurology.

Recent advances in the field of sensory evoked potentials (EPs) have allowed assessment of function in regions of the nervous system that were previously inaccessible to noninvasive electrophysiologic study. Pattern visual and brainstem auditory EPs, respectively, are more sensitive to certain optic nerve or posterior fossa lesions than either clinical or laboratory tests. Short-latency somatosensory EPs from the upper and lower extremities are sensitive to pathology at cervicomedullary and thoracolumbar levels of the neuraxis as well as to suprasegmental lesions. This article reviews the development of these tests as clinically useful tools and the applications in which they have contributed most to the practice of adult neurology.

Excretion of amines and their metabolites by two patients in hepatic coma treated with L-dopa.

Two patients in hepatic coma were treated with L-dopa. The first patient showed clear clinical improvement, but the second patient did not. Analyses of urinary metabolites indicated that L-dopa was not absorbed by the second patient. There was evidence that L-dopa had the following beneficial effects in the first patient: (1) increased production of urine, which could have been accompanied by increased excretion of toxins; (2) displacement of tyramine from transmitter sites (because increased excretion of p-hydroxyphenylacetic acid, a major metabolite of tyramine, occurred during L-dopa treatment in patient 1); (3) replenishment of dopamine, and to a much lesser extent, norepinephrine, at central or peripheral neuroeffector junctions; and (4) scavenging of methyl groups by L-dopa, because ratio of methylated amines to catecholamines was higher than normal in both comatose patients before L-dopa treatment, and this ratio decreased during L-dopa treatment in patient 1.

Prognostic value of brainstem auditory evoked potentials in neonates.

The clinical outcome in 74 children at risk for audiologic or neurologic sequelae of a variety of perinatal insults was correlated with brainstem auditory evoked potentials (BAEPs) in the newborn period. No constant relationship was found between BAEP findings and later hearing status in preterm infants or in infants with severe brain damage. However, persistent patterns of wave I abnormality correctly predicted the presence and type of hearing loss in other infants. Central BAEP abnormalities recorded in preterm infants or in infants who had just suffered anoxia had little predictive value. The abnormalities had greater prognostic value when there was a delay between acute injury and testing. Prognostic errors could be minimized in this population by obtaining repeated recordings at least one month post term and after injury from infants who showed BAEP abnormalities in the neonatal period.

Ectopic internal carotid artery seen initially as middle ear tumor.

An ectopic carotid artery is rare. Its first symptoms may be neurological and could bring the patient to the neurologist during the initial evaluation. However, more often, the neurologist examines a patient in whom serious neurological deficit has occurred after transtympanic exploration of an undiagnosed vascular mass. Because diagnosis can be definitively established by angiography and the consequences of injury to an aberrant carotid artery are serious, operative exploration of vascular middle ear masses probably should be deferred until an ectopic carotid artery has been excluded by angiography.

Brainstem auditory evoked potentials in 20 patients with palatal myoclonus.

Brainstem auditory evoked potentials (BAEPs) were obtained in 20 patients with palatal myoclonus. The group included 14 men and six women whose ages ranged from 19 to 82 years. Six of the patients had abnormal BAEPs: two with severe head trauma and one each with a brainstem infarct, tumor, demyelination, and an indeterminate inflammatory process. The 14 patients with normal BAEPs had palatal myoclonus secondary to head trauma (five patients), brainstem infarcts (four patients), cerebellar tumors (two patients), degenerative processes (two patients), and an Arnold-Chiari malformation (one patient). Since the auditory pathways are separate from the structures associated with palatal myoclonus, it is possible to have discrete lesions producing palatal myoclonus with sparing of the auditory structures, whereas diffuse or multifocal lesions of the brainstem are more likely to be associated with abnormal BAEPs.

The effects of temperature and acute alcohol intoxication on brain stem auditory evoked potentials in the cat.

The effects of core temperature changes (less than 1 degree C) and acute ethanol intoxication (100-400 mg%) on brain stem auditory evoked potentials in cats were studied independently--then together--to distinguish between a putative direct pharmacological action of ethanol on brain stem auditory neurons, as reflected in reported BAEP latency changes, and in indirect action of ethanol mediated through slight changes in central temperatures. The results suggest that the reported BAEP latency effects are attributable, largely if not entirely, to the second mechanism above. No significant temperature-independent BAEP latency alterations occurred at any sublethal blood ethanol concentration or in one dosage that subsequently proved fatal. These findings do not exclude a direct ethanol effect on brain stem auditory neurons but provide no evidence for a temperature-independent effect. Knowledge of secondary BAEP temperature effects associated with drug administration is crucial to proper interpretation of BAEPs in both experimental and clinical applications.

Brainstem auditory-evoked responses. Normal variation as a function of stimulus and subject characteristics.

Brainstem auditory-evoked responses (BAERs) were elicited from 64 neurologically and audiometrically normal adults and 77 normal, full-term neonates with broadband rarefaction or condensation clicks at sensation levels (hearing levels in neonates) of 30 to 70 dB and at rates of ten and 80 clicks per second. In addition to the known effects of rate, previously unrecognized effects of acoustic phase and stimulus intensity on BAER interpeak latencies (IPLs), and an interaction of all three stimulus parameters, were found. Stimulus characteristics, age, and sex can account for much of the inter- and intrasubject variability of BAER IPLs and morphology. The BAER effects of many of these variables and their interactions have not been appreciated in clinical applications of BAER. Recognition and control of such reducible, methodological sources of BAER variability will enhance the sensitivity and specificity of the test in neurologic diagnosis.

Effects of hypothermia on the human brainstem auditory response.

Latency measurements between three potentials (waves I, III, and IV/V) of the human brainstem auditory response can allow early detection of certain posterior fossa lesions. The diagnostic use of these interwave latencies requires knowledge of what factors may prolong them in the absence of disease. Hypothermia appears to be one such factor--in 5 neurologically and audiometrically normal patients, mean esophageal temperatures as high as 34.5 degrees C resulted in prolongations of central auditory conduction time. Interwave latency prolongations that were abnormal relative to an age-matched normal population were seen at 32.1 degrees +/- 0.3 degrees C in patients with both spontaneous and induced hypothermia, and these abnormalities disappeared after rewarming to normothermia. Hypothermia often accompanies intoxication and coma and should therefore be considered when brainstem auditory response abnormalities are being interpreted in these two clinical conditions.

Electroencephalographic abnormalities following halothane anesthesia.

In 7 subjects, serial EEGs, serum bromide determinations, and psychological tests were done prior to and following 13.83 +/- 0.74 (SEM) MAC-hours of halothane anesthesia. Significant psychological impairment demonstrated 2 days following anesthesia in these subjects was absent 2 weeks following exposure to halothane. Nonspecific postanesthetic slowing of the EEG was found, qualitatively similar to but more marked than that following exposure to enflurane. Generalized EEG slowing, with a tendency toward posterior delta activity and significant reduction of frequency and amplitude of the alpha rhythm, persisted for 6 to 8 days following anesthesia. Rare sharp-wave activity developed in 3 subjects in the 1st week after halothane. A potentially psychoactive postanesthetic serum bromide level of 2.97 +/- 0.17 mEq/L (SEM) was found 5 days following anesthesia. Electroencephalographic changes characteristic of mild bromide intoxication were absent, suggesting that the psychological impairment noted after halothane anesthesia is probably not due to this metabolite; these psychological changes are probably due instead to persistence in the circulation of unchanged halothane.