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Biomedical subjects

M P Downs

Publications and source records attributed to M P Downs.

17 recordsLinked to original sources

Mixed lymphocyte culture reactivity of fetal baboons: application for in utero bone marrow transplantation.

Bone marrow transplantation offers a potential cure for patients suffering from genetic diseases such as inborn errors of metabolism. The optimal time to transplant many of these affected individuals would be early in gestation. To date, little information is available on the cellular immune reactivity of fetal primate lymphocytes. Therefore, we tested peripheral blood lymphocytes obtained in utero from baboon fetuses (Papio sp.) for their ability to respond in mixed lymphocyte culture (MLC) against their mothers, against a pool of unrelated animals, and in the case of fetuses given unrelated bone marrow transplants in utero, against their specific bone marrow donors. The majority of fetuses as young as 80 gestational days (182-day normal gestation period) were capable of responding strongly to maternal and unrelated lymphocytes in MLC. Of six fetuses that were transplanted, three did not engraft as indicated by undetectable levels of the donor-specific type B allele of glucose phosphate isomerase in fetal blood samples 1 month post-transplant. The three fetuses that did engraft all lost their grafts before birth. These data demonstrate that fetal lymphocytes obtained in utero can be tested for MLC reactivity and suggest that MLC testing can be used to select appropriate donor-recipient combinations for in utero bone marrow transplantation.

Animals

Early Language Milestone Scale and language screening of young children.

The purpose of this project was to evaluate the use of the Early Language Milestone Scale (ELM) in screening language skills in young children. In this study, 657 children from birth to 36 months of age were evaluated with the ELM. The overall failure rate was 8%. Children who failed the ELM screening were evaluated with the Sequenced Inventory of Communication Development (SICD) that was used as the "gold standard" for diagnosing language disorders. In the 12-month age and younger group, there was poor agreement between the ELM Scale and the SICD. For infants 13 to 24 months of age, there was moderately good agreement between the SICD and a second ELM that was administered 1 to 2 weeks after the initial screening. In the 25- to 36-month age group, there was excellent agreement between the SICD and a rescreen ELM. The agreement between the two instruments indicated that the rescreen ELM correctly classified 79% of the 13- to 24-month-old infants and 89% of the 25- to 36-month-old toddlers.

Child, Preschool

Effects of mild hearing loss on auditory processing.

The impact on language learning of mild hearing loss due to otitis media with effusion has forced a new look at the dynamics of central auditory processing. A model of auditory deprivation that would produce the test results that define CAP deficits would be a mild conductive hearing loss. It is relevant to reexamine CAP theory in terms of such hearing loss.

Auditory Perceptual Disorders

Hearing loss in Down's syndrome. A treatable handicap more common than generally recognized.

Significant hearing loss was found in about two-thirds of a series of 107 individuals with Down's syndrome. Hearing loss of that degree causes retardation of speech, language and intellectual development in normal children. Down's children are presumably affected even more by this sensory deprivation and without correction are prevented from reaching their full potential.

Adolescent

Auditory screening.

Hearing screening is one of the most viable techniques in the health screening arena. The procedures are sufficiently valid and flexible to meet the requisite goals at any age level. The yields are easily great enough to justify the relatively small expenditures for screening programs. When one considers that the proper identification of hearing loss can create fulfillment in life that would not otherwise have been possible, it is evident that these programs should be implemented universally.

Acoustic Impedance Tests

Ossicular abnormalities in Down's syndrome.

Down's syndrome has been associated with hearing loss and otitis media. Because of difficulty in examination, however, there have been few detailed otologic studies on this population. An understanding of the nature and frequency of ear disease in Down's syndrome is important, since it is common and occurs in more than one in every 600 live births. To define the aural manifestation of Down's syndrome, complete otologic and audiometric examination was performed on 107 consecutive patients. This included micropneumatic otoscopy, pure-tone and speech audiometry, impedance tympanometry, and, in some cases, electronystagmography. Deficient hearing was found in 64% of these patients, and of these hearing losses, 83% were conductive. Surprisingly, middle ear effusion or tympanic membrane perforation accounted for only 60% of the conductive hearing losses. This finding prompted us to examine five temporal bones of children with Down's syndrome. These histologic sections revealed middle ear abnormalities including fixation and superstructure deformity of the stapes and dehiscence of the fallopian canal. Operative findings in 16 procedures on patients with Down's syndrome and conductive hearing loss suport those findings.

Adolescent