Responding to child maltreatment.
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Child↗
Biomedical subjects
S B Ryan
Publications and source records attributed to S B Ryan.
Mechanisms of interhemispheric transfer and patterns of cognitive function in acallosal patients of normal intelligence.
We investigated interhemispheric transfer and cognitive function in two boys with normal intelligence in whom agenesis of the corpus callosum was identified following minor head trauma. In patient 1, magnetic resonance imaging scan showed agenesis of the corpus callosum and absent anterior commissure. Results of visual interhemispheric transfer tasks suggested degradation in transfer of information to the left hemisphere. Results of a tactile interhemispheric transfer task suggested degradation of access to the right hemisphere. In patient 2, magnetic resonance imaging scan showed agenesis of the corpus callosum and enlarged anterior commissure. Results for both visual and tactile interhemispheric transfer tasks were normal. Dichotic listening tests showed a slight left ear advantage in both patients. These results support the hypothesis that hypertrophy of the anterior commissure is an important mechanism of functional compensation in agenesis of the corpus callosum. However, the relative subtlety of deficits in patient 1 and results of dichotic listening tests support use of other mechanisms as well. No consistent pattern of cognitive deficits was observed.
Agenesis of Corpus Callosum↗
Cerebral disconnection in multiple sclerosis. Relationship to atrophy of the corpus callosum.
Left ear suppression to dichotically presented verbal stimuli has been observed in patients with multiple sclerosis (MS). Rubens and coworkers have suggested that a disconnection of the auditory callosal pathways may account for this finding. To examine this proposal, we compared the performance of 28 MS patients with significant corpus callosum atrophy (CCA) on midsagittal magnetic resonance scans, 16 MS patients without significant CCA, and 64 demographically matched normal control subjects on two laterality tasks: verbal dichotic listening (consonant-vowel syllables) and tachistiscopic object-naming latency. Results indicated that left ear suppression was found only in the MS patients with CCA. Likewise, patients in the MS group with CCA were slow in responding to stimuli presented in the left visual field; this effect was not observed in patients without CCA. These findings support the hypothesis that efficiency of cross-callosal information flow is reduced in MS patients with CCA.
Adult↗
The influence of duplex scanning on early patency rates of in situ bypass to the tibial vessels.
Duplex scanning was used in the follow up of 49 in situ infrapopliteal bypasses per formed for limb salvage using the valve incision method. In 19 cases (39%) the peroneal artery was the best available vessel for distal insertion; the anterior tibial and dorsalis pedis were used in 17 cases (35%) and the posterior tibial artery and tibioperoneal trunk in 13 cases (26%). In the early postoperative period three AV fistulas presented with painful skin lesions. These were located using duplex scanning and following ligation rapid resolution followed. Primary patency at one month was 87% and was increased to 96% by successful correction of four out of six failed bypasses. A total of 11 stenoses were found in five bypasses between three and 15 months postoperatively. In four of these patients the ankle/arm index decreased by at least 0.15 between examinations. A comparison was made between the spectral analysis on duplex scanning and the findings on arteriography and at operation. Peak systolic frequencies greater than 6,000 Hz were associated with 50% or greater reduction in vein bypass diameter. The majority were corrected using vein patch angioplasty. Primary cumulative patency at two years was maintained at 68% while correction of two out of seven bypass failures raised this to 80%. Duplex scanning allows precise definition of vein bypass pathology, facilitates operative correction and increases long-term limb salvage.
Aged↗
Systematic comparison of antibody-mediated mechanisms of keratinocyte lysis in vitro.
We have conducted a systematic comparison of lysis of TNP-coated keratinocyte targets by TNP-specific antibody, by antibody plus complement, by antibody-dependent cellular cytotoxicity (ADCC), and by natural killing with the use of monocyte, lymphocyte, and neutrophil effectors. With chromium-release assays, human keratinocytes, HEp-2 cells (transformed human keratinocytes), PAM 212 cells (transformed mouse keratinocytes), and RSC (transformed rabbit keratinocytes) were all susceptible to monocyte- and lymphocyte-mediated ADCC (p less than 0.01 to p less than 0.02). All trypsinized keratinocyte targets were also susceptible to natural killing by monocyte or lymphocyte effectors (p = 0.05 to p less than 0.001). Antibody and antibody plus complement were poor mediators of keratinocyte lysis. If protein and complex lipid synthesis of keratinocytes were inhibited by 16-hr cycloheximide preincubation, then keratinocytes were susceptible to complement-mediated lysis, implying that the resistance of these cells to complement may be due to repair of transmembrane pores. Comparison of chromium-release assays with fluorescein diacetate dye uptake viability assays showed that human keratinocytes were still susceptible to monocyte and lymphocyte ADCC but not to antibody, antibody plus complement, or natural killing. The reproducible and uniform susceptibility of normal and transformed keratinocyte targets from three different species to monocyte and lymphocyte ADCC supports the hypothesis that this mechanism of cellular lysis may be important in antibody-associated diseases of epidermal cytotoxicity.
Animals↗
Mesoionic xanthine analogs as inhibitors of cyclic AMP phosphodiesterase.
Several derivatives of two mesoionic xanthine analogs, mesoionic thiazolo[3,2-alpha]pyrimidine-5,7-diones and mesoionic 1,3,4-thiadiazolo[3,2-alpha]pyrimidine-5,7-diones, were synthesized and evaluated as inhibitors of cyclic AMP phosphodiesterase. A significant number of these compounds demonstrated theophylline-like activity.
3',5'-Cyclic-AMP Phosphodiesterases↗
A struggle with optimal child care.
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Attitude of Health Personnel↗