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Biomedical subjects

K Smith

Publications and source records attributed to K Smith.

At least 163 records · Page 9Linked to original sources
PubMed1999

Stromal progenitor cells present within liposuction and reduction abdominoplasty fat for autologous transfer to aged skin.

BACKGROUND: Autologous fat is used for direct transfer to locally replace fat, as well as for use intradermally in the treatment of rhytids in aged skin. OBJECTIVE: To determine if the components of the autologous fat could be separated to produce a better agent for the treatment of rhytids. METHODS: Liposuction material from four patients and fat from abdominoplasty from five patients was processed by homogenization and centrifugation to separate mature lipocytes from other stromal cell populations in its associated extracellular matrix, and then to separate this from the blood and cellular debris. The cellular layer was evaluated histologically and with the immunohistochemical antibodies for CD34, SM-actin, S-100 protein, MIB-1, Bcl-2, and factor XIIIa. RESULTS: The cellular layer showed spindle cells, some small vascular structures, a small amount of mature fat, and extracellular matrix. CD34 showed diffuse staining of most spindle and endothelial cells in all sections, factor XIIIa showed only focal staining of spindle and dendritic cells, and Bcl-2 showed light to moderate staining in scattered cells within the cellular component. S-100 protein, SM-actin, and MIB-1 were negative. CONCLUSION: Processed liposuction and abdominoplasty processed fat may be ideal for the treatment of wrinkles in aged skin because it contains progenitor stromal cells that are known to be present within the fat and which may be concentrated by processing methods.

Abdomen↗
PubMed1999

Adjunctive therapy in epilepsy: a cost-effectiveness comparison of two AEDs.

The objective of this study was to compare the relative cost-effectiveness of two AEDs by a prospective clinical audit. Patients starting on the adjunctive therapies lamotrigine and topiramate were recruited from the out-patient epilepsy clinics at Queen Square. Three interview were scheduled: baseline; three months follow-up and six months from baseline. Of the 81 patients recruited, a total of 73 patients completed all three interviews. An intention to treat analysis was performed on the data. Seizure severity and frequency were assessed using the National Hospital Seizure Severity Scale. Side-effects, adverse events and reasons for stopping medication were also recorded. At the third interview, a total of 47/73 (64%) were still on the prescribed adjunctive drug. Outcome was assessed by two methods: the > 50% seizure reduction cited in the literature and a more stringent assessment of patient 'satisfaction' which we defined operationally on clinical criteria. Using this definition, a total of 10/73 (14%) patients were 'satisfied'. The relative costs of starting patients on each of the two AEDs were calculated, both drug costs and the costs of adverse events (the latter were defined as events requiring urgent medical attention). The costs of the two drugs were compared. A number of methodological issues relating to cost comparison are discussed. Outcome and pharmaco-economic studies need to assess more than reduction in number of seizures. They should take into account variables important for quality of life including side-effects and adverse events.

Adult↗
PubMed1999

A brief motivational intervention to improve dietary adherence in adolescents. The Dietary Intervention Study in Children (DISC) Research Group.

Motivational interviewing offers health care professionals a potentially effective strategy for increasing a patient's readiness to change health behaviors. Recently, elements of motivational interviewing and the stages of change model have been simplified and adapted for use with patients in brief clinical encounters. This paper describes in detail a brief motivational intervention model to improve and renew dietary adherence with adolescents in the Dietary Intervention Study in Children (DISC). DISC is a randomized, multi-center clinical trial assessing the efficacy and safety of lowering dietary fat to decrease low-density lipoprotein cholesterol in high-risk children. In the first 3 years of follow-up covering ages 8-13, intervention participants (n = 334) were exposed to a family-based group intervention approach to change dietary choices. To address adherence and retention obstacles as participants moved into adolescence (age 13-17), an individual-level motivational intervention was implemented. The DISC motivational intervention integrates several intervention models: stages of change, motivational interviewing, brief negotiation and behavioral self-management. A preliminary test of the intervention model suggests that it was acceptable to the participants, popular with interventionists and appeared to be an age-appropriate shift from a family-based intervention model.

Adolescent↗
PubMed1999

Modeling analysis of change in neurologic abnormalities in children born prematurely: a novel approach.

The purpose of this longitudinal study was to evaluate changes in neurologic abnormalities in 212 preterm and 128 full-term children. Preterm infants with severe medical complications were considered at high risk, while those with milder complications were considered at low risk for neurodevelopmental abnormality. The patterns of change in neurologic status for the high- and low-risk preterm and term groups across 6, 12, 24, 40, and 54 months of age were compared using growth modeling analysis. As expected, the term group showed minimal change, while the two preterm groups demonstrated complex, nonlinear patterns of change in neurologic abnormalities. While the results demonstrate improvement over time in both groups of preterm infants, 35% of the children in the high-risk group had neurologic scores in the borderline or abnormal range at 54 months. These findings demonstrate that neurologic deficits are still evident at preschool age in some preterm children and that these deficits are related to the severity of neonatal complications.

Brain Damage, Chronic↗
PubMed1999

Increased soft tissue in the posterior cervical and upper back area of patients on HIV-1 protease inhibitors.

BACKGROUND: Corticosteroids as well as sex hormones affect the redistribution of subcutaneous fat and the percentage of lean body mass. In addition, some stromal cells express steroid receptors, and the quantity and distribution of these receptors vary at different body sites and between sexes. Inhibitors of HIV-1 protease may affect steroid hormone metabolism through their effect on cytochrome P450. OBJECTIVES: To determine the changes in the tissue of the back in three HIV-1+ patients who developed increased soft tissue in posterior cervical and upper back areas while on HIV-1 protease inhibitors. METHODS: Punch biopsies of the involved posterior cervical and upper back areas were done. These included subcutaneous adipose tissue. Routine hematoxylin and eosin-stained sections, along with special stains for elastic and stromal mucin, and immunohistochemical stains for CD34 (HPCA-1 and Factor XIIIa) were evaluated. RESULTS: Histologically all three patients showed identical features. There was expansion of the dermis with decreased periadnexal fat and marked widening of the fibrous septa within the expanded subcutaneous fat. CONCLUSIONS: The posterior cervical and upper back area appears to be a common site for localization of mesenchymal tumours that show some fat differentiation and produce an increase in stromal matrix material. Mesenchymal cell populations within this area are also affected by systemic diseases. A male predominance pattern occurs with these conditions, and steroid receptors are expressed on some mesenchymal cells, that vary with the body location. Thus, this observation may be related to the effects of protease inhibitors on steroid hormone metabolism through their inhibition of cytochrome P-450.

Adipose Tissue↗
PubMed1999

The predictive value of findings of the common aneuploidies, trisomies 13, 18 and 21, and numerical sex chromosome abnormalities at CVS: experience from the ACC U.K. Collaborative Study. Association of Clinical Cytogeneticists Prenatal Diagnosis Working Party.

We report 611 non-mosaic and 91 mosaic findings of trisomies 13, 18 and 21, and numerical sex chromosome abnormalities in a series of 20,527 CVS, in the Association of Clinical Cytogeneticists U.K. Collaborative Study, the majority with analysis of both direct preparations and cultured cells. No false-positive results were encountered among the 611 non-mosaic cases, making these findings a very reliable indicator of the fetal karyotype. One false-negative case was reported. In contrast, the 91 mosaic abnormalities were unreliable predictors of fetal abnormality. Many were associated with normal outcomes, but a significant proportion of cases of each individual aneuploidy proved genuine. Mosaicism for 45,X, and trisomies 13 and 18 was disproportionately common. 17 of the mosaic cases showed complete discordance between the karyotype from direct preparations and that from cultured cells. All would have resulted in either a false-positive or a false-negative finding if only one technique had been used. Based on our experience, and that of others, we believe that the highest level of predictive accuracy using CVS can only be achieved if both direct preparation and cell culture are performed. In addition, we continue to recommend that all pregnancies demonstrating mosaicism for these aneuploidies at CVS undergo amniocentesis or fetal blood sampling to differentiate between confined placental mosaicism and true fetal karyotypic abnormality.

Aneuploidy↗
PubMed1999

[Mechanisms and control of meiotic recombination in the yeast Saccharomyces cerevisiae].

Recent studies in Saccharomyces cerevisiae have provided new insights in our understanding of the molecular mechanisms of meiotic recombination. Meiosis-specific DNA double-strand breaks have been detected and have been shown to be the lesions that initiate recombination events. These are located mostly in promoter regions where the chromatin is in an open configuration, and cluster in domains along the chromosome. They are likely to be made by a topoisomerase II-like protein encoded by the SPO11 gene. Several DNA intermediates in the meiotic double strand-break repair pathway have been characterised and several multi-protein complexes have been identified and shown to be involved at different steps in the repair pathway. The conservation of these protein complexes in higher eukaryotes suggests that the meiotic recombination mechanism could be conserved. With the application of the well characterised genetical, molecular, cytological and biochemical techniques and the recently developed technology for genomic studies (biochips), we can expect a rapid increase in our comprehension of the meiotic recombination process.

Chromosomes, Fungal↗
PubMed1999

Electrophysiological evidence of cortical fusion in children with early-onset esotropia.

PURPOSE: To investigate sensory fusion responses in infants and children with early-onset esotropia to gain insights into the sequence of events that leads to strabismus. METHODS: Sensory fusion was tested by measuring visual evoked potential (VEP) responses to dynamic random dot correlograms (DRDCs) in a group of children (n = 23) with early-onset esotropia. Thirteen children were tested before surgical alignment, and 13 children were tested after surgical alignment (three children were tested before and after surgery). If the angle of strabismus was larger than 5 prism diopters, it was corrected with Fresnel prisms (Fresnel Prism and Lens, Scottsdale, AZ). RESULTS: Five (38%) of the 13 children who were tested before surgery showed detectable VEP responses to correlogram stimuli compared with 11 (85%) of the 13 children who were tested after surgical alignment. There were no significant statistical differences between VEP responses to DRDCs from the postsurgery group and VEP responses from an age-matched control group with normal binocular vision. CONCLUSIONS: The presence of cortical sensory fusion in children with early-onset esotropia suggests that a congenital defect of sensory fusion cannot be the root cause of esotropia in most children. The data suggest that sensory fusion, when measured by VEP responses to DRDCs, is more robust than stereopsis to abnormal binocular experience and support the notion that pathways processing correlated/anticorrelated stimuli may not completely overlap with pathways processing disparity information.

Child↗