Bovine leukemia virus and cow longevity in Michigan dairy herds.

To determine the association between infection with bovine leukemia virus (BLV) and cow longevity, a stratified random sample of 3,849 Holsteins in 112 Michigan dairy herds was followed for an average of 597 d following testing for BLV antibodies with an ELISA milk test. The hazard ratio of 1.23 indicates that BLV-positive cows were 23% more likely than their BLV-negative herd mates to die or be culled during the monitoring period. This result is adjusted for lactation number, which is also positively associated with an increased risk of leaving the herd. Because herd was included in models, the effect of BLV ELISA on cow longevity was a within-herd comparison in which BLV-infected cattle were compared with their uninfected herd mates. The analysis of 4 ELISA optical density (OD) groups demonstrated a dose response such that cows with higher OD values had decreased survival compared with cows with lower OD values. Cows with OD values above 0.5 were at 40% greater risk of dying or being culled than were their uninfected herd mates. These results support the contention that the association of BLV with cow longevity, when added to other economic impacts, may warrant the control of BLV in our US dairy cow population.

Germline diversity of the expressed BALB/c VhJ558 gene family.

Although the mouse immunoglobulin heavy chain (Igh) locus contains 15 heavy chain V (Vh) gene families, at least half of the Vh gene segments are members of the VhJ558 family. This large Vh gene family represents the least characterized germline coding regions of any of the mouse antigen receptor loci and the contribution of individual VhJ558 genes to the preimmune repertoire is poorly understood. In fact, relatively few germline VhJ558 sequences have been reported for BALB/c, the foundation strain for mouse immunoglobulin genetics and the prototypic strain of the Igh(a) haplotype. Here we present a database consisting of 66 sequences estimated to represent one-half of the total number of functional BALB/c VhJ558 genes. Our results indicate that a subset of the VhJ558 genes is highly expressed in the preimmune repertoire, with just nine Vh sequences accounting for nearly 50% of the VhJ558 heavy chains expressed by splenic B cells. We show that this disparity in the expressed Vh gene repertoire is not due to the position of the Vh genes relative to the Dh cluster or to multiple germline copies of the highly expressed VhJ558 genes. Together, these data constitute the first detailed analysis of functional BALB/c VhJ558 genes, demonstrate a striking bias in the use of particular VhJ558 genes in the preimmune repertoire, and provide sufficient information to study the regulation of the Dh-distal region of the Igh-V locus at the level of individual genes.

Germline structure and differential utilization of Igha and Ighb VH10 genes.

Ab heavy chains encoded by mouse VH10 genes have been of particular interest due to their frequent association with DNA binding. We reported previously that VH10 sequences are over-represented in the preimmune repertoire considering the apparent number of germline-encoded VH10 gene segments. In this report, we show that the VH10 family consists of three and two germline genes in the Igha and Ighb haplotypes, respectively. The complete nucleotide sequences of these five genes, including promoters and recombination signal sequences, were determined and allow unambiguous assignment of allelic relationships. The usage of individual VH10 genes varied significantly and ranged from 0.2% to an extraordinary 7.2% of the VH genes expressed by splenic B cells. Since the promoter and recombination signal sequence elements of all five VH10 genes are identical, we suggest that the few amino acid differences encoded by these five germline VH10 genes determine their representation in the preimmune repertoire. Rearrangements of the most frequently used VH10 gene have an apparent bias for histidine at position 95 of complementarity-determining region-3 (CDR3). These CDR3s are also biased for asparagine, an amino acid associated with the CDRs of DNA binding Abs. Together, these results suggest that high VH10 gene use is the result of B cell receptor-mediated selection and may involve DNA and/or ligands that share antigenic features with DNA.

Spectral analysis of infant EEG and behavioral outcome at age five.

Power spectral and discriminant analysis techniques were used to compare EEG records obtained at term and at 3 months past term from 5 groups of varying risk and developmental outcome. The groups were: healthy full-terms; healthy pre-terms with normal outcomes; sick pre-terms with normal outcomes; sick pre-terms with delayed development; sick pre-terms with later neurological problems. The EEG samples recorded at term were identified as belonging to the correct subject group at 52-70% accuracy, 20% being chance for 5 groups. The accuracy varied with the 4 classes of EEG patterns used. The individual subjects were also classified into their correct groups with few exceptions. Similar success was obtained with EEG samples selected from recording at 3 months past term. The predominant power spectral discriminating features were changes in intra- and inter-hemispheric coherence, and increased power, particularly in the middle and higher frequency range. Thus, computer analyses of EEG samples, using features not readily identified visually, differentiated risk from non-risk infants and also differentiated infants with substantial neonatal medical complications who have good or poor developmental outcomes.

EEG patterns of preterm infants, home environment, and later IQ.

As part of a prospective longitudinal study of preterm infants, sleep state organization and EEG patterns were studied at term date in 53 preterm infants as an index of the maturity and integrity of neurophysiological organization that might have implications for their later development. The rearing environments of the infants were also assessed, using time sampling of caregiver-infant interaction during home observations when the infants were 1, 8, and 24 months. The infants were tested at 4, 9, and 24 months on the Gesell Developmental Scale. At age 5 the children were tested by the Stanford-Binet Intelligence Scale, and at age 8 by the Wechsler Intelligence Scale for Children. In general, children who at term date showed less 407-Tracé Alternant EEG pattern in the entire record and particularly in quiet sleep had lower IQs beginning at 4 months and continuing to age 8. There was an exception, however, for those children being reared in consistently attentive, responsive environments. They, by 24 months and continuing to age 8, had higher IQ scores, equal to those of infants with more 407-Tracé Alternant, even if they had shown decreased amounts of 407-Tracé Alternant earlier.

Cognitive development in preterm infants: birth to 8 years.

This report summarizes the outcome at age 8 of a group of preterm infants followed intensively from birth. The study was designed primarily to follow the processes of interaction between biological and environmental factors in determining the childhood outcome of infants born preterm rather than to report the incidence of particular types of outcomes for special subgroups of infants. A high percentage of the children were performing within the normal range. Social factors played a major role in determining the outcome regardless of neonatal complications. Functional assessment of newborn visual attention and sleep organization showed a modest relation to outcome. A subgroup of preterm infants from Spanish-speaking families, for cultural and language integration reasons, followed a somewhat different course from infancy to childhood outcome than did the group from English-speaking families. The results suggest that in longitudinal studies of preterm infants, different cultural and language groups should be analyzed separately so that one may understand the developmental processes and outcomes.

Children's illnesses: their beneficial effects on behavioral development.

The theme of this presentation concerns the potential beneficial effects of children's illnesses on their behavioral development. Illnesses of a minor nature such as colds and gastrointestinal upsets are frequent events in the lives of all children at every age, but are most frequent in the preschool period. They are generally not life threatening and are managed within the family, day-care center, or school. These illnesses, like other life perturbations, can expand children's personal and social experiences in ways beneficial to their behavioral development. They provide many opportunities for children to increase their knowledge of self, other, prosocial behavior, and empathy, as well as a realistic understanding of the sick role. This knowledge is gained, not only from their personal feelings and social experiences while ill, but also by their observations of siblings, parents, and peers as they become ill and recover, often in quick succession after their own experience. This important subject has seldom been studied from a developmental point of view. The conceptualizations as presented are based on the author's clinical experiences and the existing related research. It is the author's hope that in the future developmental psychologists, sociologists, anthropologists, and other behavioral scientists will study children's illnesses as part of normal behavioral development.

Somatic growth and developmental functioning in children receiving prolonged home total parenteral nutrition.

Growth and psychomotor development in nine infants receiving prolonged home total parenteral nutrition (TPN) were studied longitudinally from infancy to 3 years of age. Although these children had received TPN for, on average, 79% of their lives, normalization of somatic growth occurred by 2 years of age in all of them. Three children maintained average or above average levels of developmental performance over the 3-year study period. Another four children had initially delayed development but average or above average developmental scores by 18 months. In two children the rate of development gradually slowed without obvious cause, so that by 3 years they functioned in the below average to mildly retarded range.

Infant mental health and biological risk.

Parents seldom seek help directly for infant mental health problems. Parents enter the health care system seeking advice for identified or presumed biological problems in their infants. Many of these biological problems, however, have major psychosocial components of importance to infant mental health. It is important that physicians deal directly with the psychosocial issues and avoid converting them into biological medical problems unintentionally. Three common types of problems and appropriate methods of management are discussed to ensure special recognition and effective handling by the physician of psychosocial problems and the promotion of mental health. The problems discussed are the following: Infants seen with defined medical conditions that generally have associated psychosocial problems including child abuse. Infants seen who have fully recovered from critical illnesses but are considered "at risk" for later developmental disability. Infants seen with normal variations of behavior that are misinterpreted by their parents or physicians as due to a medical problem. In infancy medical and psychosocial issues are so closely interwoven that it is critical that physicians learn to recognize the major psychosocial consequences of primary medical problems and the medical manifestations of primary psychosocial problems and their management.

Prediction of five-year Stanford-Binet scores in preterm infants.

The development of a group of 100 preterm infants, mean birth weight 1,877 grams, from a broad range of social class and ethnic backgrounds was followed from birth to age 5. Assessments in infancy were directed at medical problems and early perceptual, motor, social, and cognitive development. The child's performance on the Stanford-Binet test at age 5 could not be predicted from early hazardous events in the obstetrical or neonatal period. The results indicate that developmental outcome at age 5 could be predicted moderately from a single measure, infant visual attention, administered as early as term date. Prediction was improved by using a combination of assessments given during the first 9 months. Furthermore, prediction was significantly better for girls than for boys. Although moderate stability in performance was found for the group as a whole, prediction of an individual's performance resulted in a substantial number of children being misclassified. Social factors were more important than any other set of factors in relating to the child's mental performance at age 5.

Sleep behavior of preterm children at three years of age.

Caregivers of 50 preterm children completed a questionnaire relating to their child's sleep behavior at three years of age. Assessments of the children's EEGs at term and three months, medical status at birth and at four, nine and 24 months, caregiver-child interaction at one, eight and 24 months, the Bayley Scales at 25 months and the Stanford-Binet at five years of age were also obtained. Sleep disturbances were frequently noted at three years of age. However, by five years of age, the number of reported sleep-problem children was greatly reduced, and they were not the same children with sleep problems at three years. Surprisingly, children with the greatest difficulty falling asleep at night at three years were likely to have had fewer medical problems, higher scores on the Bayley scales, and more positive social interactions with their caregivers in the first two years. The relationships among early physical, psychological and social development and sleep behavior are discussed.

Neonatal risk factors in preterm infants.

This paper highlights the research literature on neonatal risk factors and explores the paradox that these factors present. Clinical and retrospective studies indicate that children who have developmental problems have had birth complications. On the other hand, birth complications do not predict developmental problems. Data from a longitudinal study of preterm infants are presented. A group of 59 preterm infants from English Speaking homes was assessed repeatedly from birth to age 5. A significant percentage of the children performed within the normal range or above, at each assessment period. Obstetrical and postnatal complications were not significantly related to developmental performance at any assessment period yet sickness was not to be dismissed as a risk factor. At age five, all of the children who performed poorly had experienced complications in the neonatal period. Responsive caregiving appeared to be an important factor in modifying and supporting cognitive development.