Gestation length and sex of child.
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Biomedical subjects
Publications and source records attributed to M E Bernstein.
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This study explores an aspect of information delivery to parents by focusing on those who have chosen residential school placements for their children. Although most parents choose to send their deaf children to special programs in regular public schools, some do opt for residential school placements. Little is known about the foundations on which such decisions are made, and this study is a preliminary attempt to better understand parents' motives and expectations and to assess the adequacy of information provided to them. In 128 surveys from a sample of parents nationwide, a surprising number reported that they were not given information about placement options. Of those who were, many said they were dissatisfied with the information. A large proportion of the parents were satisfied with the residential school. The relationships among their reasons for this placement, their views of the advantages and disadvantages, and the information provided to them are discussed.
Public Law 99-457 has renewed interest in providing preschool education for hearing-impaired children. It is not clear, however, whether we're ready for this mandate to expand services to an ever-younger population and its families. This study presents a "snapshot" of the trends in preschool programs and of the availability of programming to students in various parts of the country. We obtained lists of programs from a sample of state level special education offices, and then sent the programs detailed questionnaires. The returned surveys provided a snapshot of the instructional approaches used in many preschool programs and indicated that there may still be some problems in the availability of preschool programming and in the ability of programs to uniformly provide the sorts of quality comprehensive services mandated by the law.
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Synaptogenesis was studied in the rat suprachiasmatic nucleus (SCN) using quantitative ultrastructural analysis and synapsin I immunohistochemistry. SCN neurons are formed between embryonic days 13 and 17 (E13-E17), and the SCN is a distinct hypothalamic nucleus by E18. At E19 the nucleus is very immature and there are few synapses. Synaptogenesis proceeds slowly until P4 but increases rapidly between P4 and P10. At P10 the number of synapses per unit area is the same as in the adult SCN and all synaptic types present in the adult are evident. However, the SCN continues to increase in volume to the adult with approximately 30% of total synaptic number added between P10 and a young adult age. The appearance of synapsin I immunoreactivity correlates very precisely with the development of synapses in the SCN as shown by ultrastructural analysis between E19 and P6. The pattern of appearance of synapsin I immunoreactivity demonstrates that synaptogenesis in the SCN is significantly delayed in comparison to adjacent hypothalamic nuclei. Synapsin I immunohistochemistry is a reliable marker of synapse formation in the developing SCN. A correlation of these anatomical data with prior functional studies suggests that SCN neurons are born as individual circadian oscillators that undergo a rapid development in the first 10 days after birth to form a functional neural network subserving circadian rhythm generation and regulation.
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This paper places into perspective the available data on agents inducing male reproductive toxicity, structural correlates that can be drawn from these data, and a scenario of action to resolve potential concerns.
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The effect of puromycin on spinal cord regeneration was studied following implantation into the site of spinal cord hemi- or transection of Gel-foam saturated with puromycin (1 mM) in a saline carrier, implantation of Gel-foam sponge saturated with saline (carrier control), or lesion alone (lesion control). The spinal cords of 107 rats were studied with light and electron microscopy 7, 14, 30, 60 and 90 days postoperative (DPO). Spinal cord hemisected animals developed a dense cicatrix at the site of lesion replete with connective tissue, blood vessles, and myelinated and unmyelinated nerve fibres which could be traced to peripheral sources. Rostrally at the C.N.S.--cicatrix interface, there were reactive neuroglial cells, occasional nerve fibres and finger-like projections of spinal cord (due to cavitation lesions) which contained neuroglia, axons and dendrites. Implantation of saline in Gel-foam resulted in the same morphology as in hemisected animals except for increased lesion size due to mechanical factors and decreased cicatrix density during the first 30 DPO. Puromycin treatment resulted in a cicatrix with initial decreased cell density but which contained a new class of nerve fibres at 30 DPO. These nerve fibres were oriented in a rostro-caudal direction, were unmyelinated, 0.1-0.2 micron in diameter and had expanded smooth endoplasmic reticulum. Some of these nerve fibres were degenerating at 30 DPO and all were absent by 60 DPO. The puromycin-treated spinal cord within 200 micron rostral to the basal lamina contained nerve terminal conglomerates, which resembled boutons, in fascicles from 30-90 DPO (duration of experiment). Hemisection of the spinal cord by crushing 1-1 1/2 segments rostral to the site of puromycin implantation at 30 DPO resulted in degeneration of these nerve fibres in the cicatrix as well as the degeneration of nerve terminal conglomerates just rostral to the basal lamina. The regenerative capacity of the spinal cord is discussed in relationship to these findings.