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Biomedical subjects

B Pennington

Publications and source records attributed to B Pennington.

9 recordsLinked to original sources
PubMed1998

Effect of pulse duration on wound healing using a CO2 laser.

The authors investigated wound healing of incisions in the buccal mucosa of a canine model created using a CO2 laser with a short pulse structure (60 micros, 100 micros, and 120 micros) rather than a conventional continuous wave structure in a shuttered mode. The tissue from 10 animals was evaluated histologically and with tensiometry acutely and at postoperative days 3, 7, and 14. A Bonferroni-Dunn corrected ANOVA analysis at a 95% significance level was used to compare the effect of pulse duration on histologic morphology and wound tensile strength. The data indicate that shorter laser pulse durations create less lateral thermal injury (P < .009) and wounds with greater tensile strength (P < .005), resulting in earlier wound healing. The results also show that heat, sufficient to damage tissue, was conducted to adjacent tissue during laser pulses of 100 micros and longer. These results demonstrate that surgical CO2 lasers with a short pulse structure of approximately 60 micros or less could offer more prompt wound healing while maintaining the advantages of a 10.6-microm wavelength laser.

Animals↗
PubMed1988

Dyslexia subtypes: genetics, behavior, and brain imaging.

This study was designed to identify inherited subtypes of specific dyslexia and to characterize these types by a variety of studies. A previous linkage study in large three-generation families resulted in a LOD score of 3.24 at a 13% recombination frequency between dyslexia and normal variations for the short arm of chromosome 15. The odds for linkage with chromosome 15 markers are better than 1,000 to 1. We estimate that 30% of an extended series of families show linkage to chromosome 15 polymorphisms. Other linkages remain to be identified. PET scanning is being used to examine measures of regional cerebral glucose metabolism during two types of reading by (adult) dyslexics and normal readers. MRI is also being used to examine pertinent brain structures. Behavioral tests are also in progress. The long-term goals of this study are to develop specific genetic and other diagnostic techniques that can be used to test children before beginning school and to develop sufficient understanding of the abnormal brain function of each subtype so that specific and effective remedial programs can be developed.

Brain↗
PubMed1985

Handedness and cognitive functions in pervasive developmental disorders.

This paper is concerned with what abnormal handedness in Pervasive Developmental Disorders (PDD) reveals about the presence, lateralization, and severity of cerebral dysfunction in this population. From previous work, it was predicted that left-handedness would be elevated in the sample and that mixed-handedness subjects should be more impaired than those with established hand dominance. A battery of cognitive and motor tests were administered to a group of PDD children with autistic symptoms, and performance was compared for the left-handed, right-handed, and mixed-preference children. It was found that left-handers tended to do better than right-handers on all cognitive measures, while the mixed-preference children tended to be the lowest on all cognitive measures. No differences were found on motor measures. An extension of the Satz (1972) model, assuming early brain damage, was developed to explain the superiority of the left-handed children; an alternative explanation assuming anomalous lateralization patterns in the natural left-handers was also suggested.

Adolescent↗
PubMed1983

Speech and language development in 41 children with sex chromosome anomalies.

Forty-one children with sex chromosome anomalies identified from the chromosome screening of a newborn population were blindly evaluated by a speech-language pathologist, along with a control group of 31 siblings. 47,XXX girls and 47,XXY boys were found to have increased problems in auditory perception, receptive language, and expressive language; the problems of the 47,XXY boys were less severe than those of the 47,XXX group, and reflected specific deficits in their ability to process linguistic information rather than a deficit in comprehension. An increased occurrence of speech production problems among the 45,X girls was associated with the presence of oral/structural malformations that often had no measurable effect on their production of speech sounds. Although the 45,X girls and 47,XYY boys had no significant increase of problems in auditory reception, receptive language, and expressive language, the trend of the data suggested more difficulty than in the control groups. The mosaic children were not different from the control subjects. Some children in all groups were found to have normal speech and language development.

Adolescent↗
PubMed1980

Language and cognitive development in 47,XXX females followed since birth.

In this report, data are presented on language and cognitive development in an unselected group of eleven 47,XXX females, followed since birth, who are now 6--14 years old. The results of the Yale Developmental Exam (at 2 years) and the Illinois Test of Psycholinguistic Abilities (ITPA) (at 4--6 years) show an early delay in language development. Those girls who presently have serious language and learning problems were significantly delayed in first walking or talking, whereas the relatively unaffected girls were not. Results of the Wechsler Preschool and Primary Scale of Intelligence (WPPSI) at 4 years of age and the Wechsler Intelligence Scale for Children (WISC or WISC-R) at 8 years of age are similar and show a generalized depression of both verbal and nonverbal abilities. Thus, unlike 45,X females or 47,XXX males, triple-X females do not have a specifically nonverbal or verbal cognitive deficit.

Adolescent↗