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Biomedical subjects

C Lord

Publications and source records attributed to C Lord.

70 records · Page 4Linked to original sources
PubMed1988

Protein diffusivities in skinned frog skeletal muscle fibers.

In this preliminary report, we investigate the problem of why proteins appear to diffuse much more slowly in muscle cytoplasm than in aqueous solutions. Microvolumetric sampling methods were used to partition the cytoplasm of freshly skinned muscle fibers into diffusible (cytosol) and nondiffusible (cytomatrix) fractions. Some of the diffusible proteins that were identified tentatively on the basis of electrophoretic mobility are: glyceraldehyde-3-phosphate dehydrogenase, triose-P-isomerase, phosphoglycerate mutase and parvalbumin. The latter was most abundant. The apparent (radial) diffusion coefficients of these proteins in the skinned fiber were about a tenth (or less) of their value in aqueous solution. Tortuosity and viscosity factors are probably responsible for their reduced diffusivity, but binding to cytomatrix proteins or sarcoplasmic reticular structures may also contribute. The apparent diffusion coefficient of parvalbumin, a strong chelator of Ca2+, was similar to that reported for trace amounts of Ca2+ injected into skinned frog fibers under oil1), thus supporting the notion that the low apparent diffusion coefficient of Ca2+ is actually that of a Ca2+-parvalbumin complex.

Animals↗
PubMed1986

The social behavior of autistic children with younger and same-age nonhandicapped peers.

Results of a study observing autistic children's interactions with nonhandicapped and autistic peers are reported. Six 8- to 12-year-old autistic children played in dyads with younger, normally developing kindergarten children and with nonhandicapped peers matched on chronological age for 10 15-minute sessions spaced over 3 weeks and then with a playmate of the alternate age for another 10 sessions. After intervention, all subjects showed gains in proximity, orientation, and responsiveness when playing with nonhandicapped peers and with autistic classmates. Same-age nonhandicapped playmates initiated more frequently than did younger nonhandicapped playmates and were better able to modify their initiations in ways that increased the likelihood of response from the autistic children.

Age Factors↗
PubMed1985

Differences in sex ratios in autism as a function of measured intelligence.

Results from analyses of sex ratios as a function of IQ are presented for 623 autistic children (487 males, 136 females) and 506 nonautistic, communication-handicapped and behavior-disordered children (374 males, 132 females). Proportionately more autistic females were found to have IQs of 34 or below than above 34. However, a linear trend of an increasing number of males with increasing intelligence was found only for nonautistic subjects. The relevance of these findings to genetic factors and the heterogeneity of autism is discussed.

Autistic Disorder↗
PubMed1983

Communicative behavior of adults with an autistic four-year-old boy and his nonhandicapped twin brother.

Sixteen female preschool teachers were videotaped playing in dyads with a nonverbal, socially unresponsive autistic 4-year-old boy and his nonhandicapped fraternal twin brother. Eight adults were informed that the autistic child had a language disability and did not talk or understand much language; eight adults were not informed about any differences between the children. Language to the autistic child was simpler, more concrete, and more often accompanied by gestures than language to his brother for both groups of subjects. Informed teachers made greater speech modifications to the autistic child and were more successful at keeping him on-task than uninformed adults. The theoretical and practical implications of communicative adjustments to children with language and social impairments are discussed.

Adult↗
PubMed1982

Sex differences in autism.

Comparisons were made between male and female children with autism, 384 boys and 91 girls, aged 3 years to 8 years, on nonverbal measures of intelligence, adaptive functioning, receptive vocabulary, perception, and eye-hand integration, and on ratings of affect, play, and relating and human interest. Males showed more advanced performances on eye-hand integration and perception skills on the Psychoeducational Profile (PEP) and had higher nonverbal IQs social quotients, and Peabody Picture Vocabulary Test (PPVT) IQs than females. When nonverbal IQ was controlled, the main effect of sex remained; however, sex differences on PPVT scores and on eye-hand integration and perception scale disappeared. Males showed more unusual visual responses and less appropriate, more stereotypic play than females. These results are discussed in terms of hypotheses concerning sex differences in genetic thresholds and in hemispheric lateralization.

Adaptation, Psychological↗
PubMed1982

Age differences in recall of categorized material: organization or retrieval?

The independent and combined influences of organizational versus retrieval processes on age differences in recall of categorized materials were examined. Five-year-olds, 8-year-olds, and adults were tested for recall of 15 pictures from three categories under four different conditions: 1. Blocked presentation-constrained recall, in which pictures were grouped by category at presentation and Ss were constrained to recall the items by category; 2. Blocked presentation-free recall, where pictures were presented in category groups but Ss recalled items without constraints; 3. Random presentation-constrained recall, in which pictures were presented randomly, but Ss were constrained to recall by category; 4. Random presentation-free recall, where pictures were presented randomly and no retrieval constraints were imposed. Results indicated that blocked presentation improved recall performance uniformly across age. In contrast, constrained recall instructions enhanced performance of 5-year-olds more than performance of older Ss. Adults benefited from blocked presentation combined with constrained recall more than either group of children. The pattern of findings suggested that retrieval operations were relatively more important in accounting for age differences in recall of categorical material than organization at presentation.

Adult↗
PubMed1982

Aminoglutethimide therapy for advanced carcinoma of the prostate.

The results of aminoglutethimide treatment of 12 patients with advanced progressive metastatic carcinoma of the prostate are reported. As judged by performance status and analgesic requirements, there were subjective improvements in 75% of the group and side effects were minimal. No consistent objective improvements were observed but decrease in plasma androstenedione and testosterone was associated with subjective improvement in most responders. Mean survival of patients following introduction of aminoglutethimide was 6.5 months. Aminoglutethimide "medical adrenalectomy" appears safe and effective in management of advanced carcinoma of the prostate.

Aged↗
PubMedDate not supplied

Cyclic traction machine for long-term culture of fibroblast-populated collagen gels.

Our research group has been investigating the effect of cyclic deformations on the evolution of fibroblast populated collagen gels (FPCG). Since existing traction machines are not designed for such an application, we had to design a cyclic traction machine adapted to tissue culture inside an incubator over an extended period of time. Biocompatible materials were used for fabrication to allow for easy sterilization and to prevent any adverse reaction from the tissue. The traction machine is based on a computer-controlled stepping motor system for easy adjustment of the deformation amplitude and frequency. The maximum stretching speed achieved is around 1 mm/s. The traction machine can measure FPCG mechanical properties and perform rupture tests to determine its ultimate strength. Several FPCGs have been successfully cultured with the machine for up to four weeks without any adverse reaction.

Biocompatible Materials↗