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Biomedical subjects

J K Williams

Publications and source records attributed to J K Williams.

At least 37 records · Page 2Linked to original sources
PubMed2000

Impact of genome research on children and their families.

Human genome research has made it possible to identify the presence of gene mutations in persons with specific genetic, conditions, who may be carriers of genetic disorders, or who are at risk for future development of inherited diseases. Gene discovery has the potential to identify individual response to medications and new management and preventive interventions. Pediatric nurses must be informed about genetic discoveries and their implications for child and family health to act as advocates for children and their families in all child health care settings.

Child↗
PubMed2000

Consumption of soy protein reduces cholesterol absorption compared to casein protein alone or supplemented with an isoflavone extract or conjugated equine estrogen in ovariectomized cynomolgus monkeys.

Dietary intake of soy protein is associated with reductions in plasma cholesterol. Isoflavones are thought to be active components of soy and responsible for the beneficial effects because of their structural similarities to estrogen. The purposes of this study were to determine if i) soy protein or a semipurified soy extract, rich in isoflavones, is responsible for improving the lipid profile and ii) altered intestinal cholesterol metabolism is one mechanism for hypocholesterolemic effects. Ovariectomized adult female cynomolgus monkeys (40) were assigned to groups fed diets containing i) casein-lactalbumin (CAS) ii) intact soy protein (SOY), iii) CAS plus an isoflavone-rich semipurified soy extract similar in isoflavone content as SOY (ISO) or iv) CAS plus conjugated equine estrogen (CEE) for 20 wk. Cholesterol absorption was determined using the fecal isotope ratio method. Bile acid excretion was measured using the 3alpha-hydroxysteroid dehydrogenase assay. The SOY group had significantly lower total- and VLDL + LDL-cholesterol compared to the other three groups and significantly higher HDL-cholesterol compared to the CAS and CEE groups. Cholesterol absorption was significantly lower in the SOY group compared to the other groups, but bile acid excretion was not significantly affected. The hypocholesterolemic effect of soy protein appears to be mediated in part by decreased cholesterol absorption. The semipurified soy extract, rich in isoflavones, added to casein protein did not have lipid-lowering effects. Other components of soy such as saponins, phytic acid or the amino acid composition may be involved in the hypocholesterolemic effects seen in this study.

Animals↗
PubMed2000

Intralesional laser therapy of extensive hemangiomas in 100 consecutive pediatric patients.

The authors have treated 100 consecutive pediatric patients with capillary/cavernous hemangiomas (age range, 1.3 months to 16 years; mean age, 26.6 months; 30 male and 70 female patients) with intralesional laser therapy during a 3-year period. All patients have been followed for a minimum of 6 months after treatment (range, 6-36 months; mean, 18 months). Indications for intralesional laser treatment included interference with vision, blockage of the nose or mouth, ulceration, bleeding, and rapid, uncontrollable growth. The Nd:YAG laser was used in 70 patients, and the Potassium, Titanyl, Phosphate (KTP) laser was used in 30 patients. Fifty-five hemangiomas were in the head and neck region, excluding the orbit; 25 were in the trunk or extremities; 10 were periorbital; and 10 involved multiple sites. Seventy patients (70%) received one treatment, 20 patients (20%) received two treatments, 7 patients (7%) received three treatments, and 3 patients (3%) received four or more treatments. No appreciable differences were noted between treatment with the Nd:YAG and KTP lasers. Forty-six patients had more than a 90% reduction in the overall size of the hemangiomas whereas 54 patients had a 50% to 90% reduction in the size of the hemangioma. After maximal reduction in size of the cavernous component was achieved, the external capillary component, found in 68 patients, was treated with a tunable dye laser. Seventy-six patients underwent surgical resection after maximal lesion involution. Residual induration due to lesion fibrosis was treated with local steroid injections in 13 patients. There were four operative complications attributable to intralesional laser therapy. Two patients had residual midfacial weakness, and two patients had punctuated skin burns after intralesional treatment. The authors have found intralesional laser therapy to be a valuable tool in the treatment of large capillary/cavernous hemangiomas, often rendering an inoperable lesion safely resectable, or markedly decreasing the size and functional impact of the lesion.

Adolescent↗
PubMed2000

Controlled multiplanar distraction of the mandible. Part III: Laboratory studies of sagittal (anteroposterior) and horizontal (mediolateral) movements.

Distraction osteogenesis has proven to be an effective technique for the correction of mandibular deficiencies. However, problems have been encountered in achieving a final, idealized form of the mandible when using distraction devices capable of moving the bone segments in only one dimension (uniplanar). Specifically, occlusal irregularities and deficiencies in lower facial contour have been seen following uniplanar distraction. To address these problems, a distraction device capable of independent movements in three planes (multiplanar) was developed. Previously reported studies in a canine model have demonstrated that this device can successfully distract the mandible along both the sagittal axis (anteroposterior or z-axis) and the vertical axis (superoinferior or y-axis). This study examines the ability of the multiplanar device to distract along the sagittal and horizontal axes (mediolateral or x-axis). A total of 12 dogs were included in the study. All animals underwent unilateral or bilateral mandibular distraction using an external multiplanar device. After a latency period of 5 days, primary distraction along the anteroposterior axis at a rate of 1 mm/day for 10 days (10 mm total) was performed. During the following 10 days, along with an additional 11 mm to 20 mm of anteroposterior axis distraction, concomitant secondary distraction was performed along the horizontal (mediolateral) axis at a rate of 5 degrees/day (50 degrees total). Cephalometric radiographs were obtained preoperatively and at the conclusion of both anteroposterior and combined anteroposterior-mediolateral distraction. Computed tomography (CT) scans were obtained preoperatively and at the end of consolidation (28 days), after which all animals were sacrificed and the dry skulls examined. In all animals, distraction along the mediolateral or x-axis was found to change the anteroposterior projection of the mandible. Varus angulation of the device with respect to the midline of the mandible caused compression of the distracted segments and reduced the anteroposterior thrust of the mandible. In contrast, valgus positioning of the device, with respect to the midline of the mandible, created the opposite effect, increasing the distracted length in the anteroposterior direction. The bone (mandibular) segments being distracted assumed the orientation of the device only for valgus positioning of the device (producing a decrease in the bigonial distance). Conversely, there was no effect from the mediolateral angulation on the distracted segments during varus positioning of the device. A possible explanation for this finding may be a greater resistance to an increase in the bigonial distance (varus positioning of the device) posed by obstruction of lateral movement of the condyle. This stands in contrast to a decrease in the bigonial distance observed following valgus positioning of the device. These findings confirm the clinical impression that distraction along the anteroposterior or sagittal axis remains the critical or keystone therapeutic maneuver in distraction of the mandible. Mediolateral or horizontal axis distraction is best used only as a supplementary movement; in essence, it only affects the anteroposterior dimension with little impact on clinically relevant changes to the bigonial distance.

Animals↗
PubMed2000

Genetic testing and mental health: the model of Huntington disease.

Genetic aspects of mental health disorders are being identified through human genome and family research. Gene discovery makes diagnostic and presymptomatic testing possible. The discovery of a gene mutation for Huntington Disease (HD) enables at-risk persons to request presymptomatic genetic testing. When HD genetic testing is offered through HD testing centers, a multi-visit protocol is followed in which education and counseling are provided for persons considering the option to have HD gene testing. A case study illustrates the clinical and ethical issues regarding privacy and disclosure as well as the personal and family consequences of gene mutation knowledge. Analysis of the impact of genetic knowledge on persons being tested for HD provides a model for the integration of emerging genetic information into mental health nursing practice for other mental health disorders.

Confidentiality↗
PubMed1999

Intact dietary soy protein, but not adding an isoflavone-rich soy extract to casein, improves plasma lipids in ovariectomized cynomolgus monkeys.

The dietary consumption of soy protein has been linked to a reduction in coronary heart disease and improvements in a number of related risk factors. Recent investigations have focused on isoflavone components of soy protein. The purpose of this study was to examine plasma lipids and lipoproteins, particularly LDL, with the intake of intact soy protein or casein-lactalbumin diets with and without a semipurified extract of soy, rich in isoflavones. Sixty ovariectomized cynomolgus monkeys were assigned to one of three groups fed diets containing the following: 1) casein-lactalbumin as the protein source (CAS; n = 20); 2) CAS plus a semipurified extract of soy, rich in isoflavones (ISO; n = 20); or 3) intact soy protein (SOY; n = 20) for 12 wk. Lipoproteins were fractionated by combined ultracentrifugation and HPLC. Isolated LDL particles were further subfractionated by dividing the LDL peak into three fractions for compositional analyses. The SOY group had significantly lower plasma total cholesterol, VLDL plus IDL cholesterol and LDL cholesterol, and significantly less HDL cholesterol than the CAS group. LDL particles from the SOY group had a significantly less cholesteryl ester than the CAS group. The semipurified extract of soy, rich in isoflavones, added to casein-lactalbumin protein did not have the same effects as intact soy protein on plasma lipids and lipoproteins. Other components of soy protein, either alone or in combination with isoflavones, may be involved in the effects seen in this study.

Animals↗
PubMed1999

Early decannulation with bilateral mandibular distraction for tracheostomy-dependent patients.

Obstructive sleep apnea in the neonatal period may originate from a hypoplastic mandibular framework causing retroposition of the base of the tongue and an inadequate hypopharyngeal space. A tracheotomy in childhood is an effective treatment for obstructive sleep apnea, but it is associated with increased morbidity, management problems, and difficulties in social interaction. Tracheostomy-dependent pediatric patients who underwent mandibular distraction were reviewed to determine the effectiveness of this technique in achieving decannulation. A clinical review was completed to determine the status of the tracheostomy after external, unidirectional distraction in tracheostomy-dependent patients. Expansion of the mandibular framework was analyzed using traditional bony landmarks on predistraction and postdistraction lateral cephalograms. The area of the lower face was analyzed, and changes in the position of the hyoid bone were determined. Four patients with tracheostomies underwent an average of 21.3 mm and 20.8 mm of distraction on the left and right hemimandibles, respectively. The average age at the time of distraction was 2.7 years (range, 2.2 to 3.2 years). All patients underwent successful decannulation at an average of 3.8 months (range, 1.5 to 5.5 months) after completion of distraction. The area of the lower face increased 26.9 percent (range, 12.2 to 53.5 percent) after distraction, and the hyoid bone advanced an average of 14.5 mm (range, 8 to 25 mm). Bilateral mandibular distraction is an effective method of expanding the mandibular framework and concomitantly advancing the base of the tongue. The technique provides a tool for early intervention and decannulation in pediatric patients with indwelling tracheostomies secondary to mandibular deficiencies.

Cephalometry↗
PubMed1999

Desmoplastic fibroma of the zygoma.

Desmoplastic fibroma is an exceedingly rare primary bone tumor. Previous reports have not included the presentation of this tumor associated with the zygoma. This report describes the unusual presentation and surgical management of a desmoplastic fibroma of the zygoma.

Bone Neoplasms↗
PubMed1999

Adults seeking presymptomatic gene testing for Huntington disease.

PURPOSE: To describe the expectations of those seeking presymptomatic gene testing for Huntington disease (HD). Identification of the gene for HD makes it possible to conduct testing to determine if a healthy person with a family history of HD has a mutation in this gene. Presymptomatic gene testing reveals the likelihood that a person will develop an inherited disease in the future. Understanding expectations allows for more complete assessment and counseling before presymptomatic gene testing for genetic diseases. DESIGN: Descriptive qualitative. The population was people with a family history of HD. The sample was 17 asymptomatic adults with a positive family history of HD who requested presymptomatic gene identification at one tertiary genetic counseling program, 1995 to 1996. METHODS: Semi-structured interviews concerning expectations of adults seeking presymptomatic genetic testing were conducted by telephone. Interviews occurred after the individuals had requested presymptomatic gene identification but before results were reported. Content analysis was used to identify the expectations and questions of those who had decided to seek presymptomatic testing. FINDINGS: Common expectations included anticipating relief from uncertainty, hoping to plan for their future health care and life decisions, wanting to know if their children were at risk of developing HD, anticipating loss of family support from relatives, expecting relief from self monitoring, venturing into the unknown, and planning for disclosure. Participants attempted to avoid their loss of genetic privacy by withholding the decision to seek testing from their primary care providers. CONCLUSIONS: Participants seeking presymptomatic HD gene testing consider the effect of gene identification on themselves and their families. A desire to limit insurance or employment discrimination contributes to subjects not seeking input from health care providers in their decision making.

Adolescent↗
PubMed1999

The role of social work in HIV/AIDS clinical trials.

The social worker can facilitate screening, retention and patient adherence in HIV/AIDS clinical trials. This paper introduces the process and its key vocabulary, and uses three case studies to demonstrate how social workers can assist clients who may wish to participate in, or are already enrolled in a clinical trial. After examining five major issues that affect the client in a clinical trial (informed consent; treatment vs. research; risks and side effects; altruism; the role of family members; and gender, race and class issues), the authors elaborate on interventions at the screening level, and concrete services and psychosocial interventions for study participants.

Adult↗
PubMed1999

State of the art in craniofacial surgery: nonsyndromic craniosynostosis.

Craniosynostosis refers to the premature fusion of one of the six major sutures of the cranial vault. Functionally, craniosynostosis may be defined as the premature conversion of the dynamic region of growth and resorption between two adjacent bones of the cranium into a static region of bony union. Molecular analysis has blurred the traditional categories of nonsyndromic and syndromic synostosis to some extent, but, in general, the distinctions between the two groups still hold true. The complexity of the congenital anomalies may be limited with the former, whereas the latter usually requires reoperations and correction of the facial skeleton. This article briefly outlines the characteristic deformities produced from nonsyndromic craniosynostosis. Various approaches to surgical correction of the deformities are described. Finally, new biomaterials that are used in the correction of nonsyndromic craniosynostosis are reviewed.

Absorbable Implants↗
PubMed1999

Fragile X syndrome.

Fragile X syndrome is the most common inherited condition causing mental retardation in males. Females with the full mutation expansion can have milder signs of the disorder. Families with members who have been diagnosed with fragile X syndrome face concerns about the health of their newborn infant, decisions regarding family planning, and questions about the possibility that other family members could have this disorder. Neonatal nurses participate in assessment, health care management, counseling, and referral of the families regarding this syndrome.

Female↗
PubMed1999

The role of distraction osteogenesis in the management of craniofacial disorders.

Since its introduction in the medical literature in 1992 by McCarthy, distraction osteogenesis of the craniofacial skeleton has become a standard surgical therapy. The present report attempts to trace the development of craniofacial distraction from the perspective of one of the early proponents of the technique. Although the earliest application of distraction was in children with severe unilateral or bilateral mandibular deficiency, its use for functional abnormalities such as apnoea were especially appealing. Distraction osteogenesis for the midface began with external appliances that were attached to the teeth. Newer, buried devices have eliminated the need for external devices in all LeFort III and monobloc cases. For LeFort I and mandibular cases, the ideal internal device has not been manufactured.

Child↗
PubMed1998

Pravastatin has cholesterol-lowering independent effects on the artery wall of atherosclerotic monkeys.

OBJECTIVES: This study examined the direct effects of pravastatin on the artery wall of atherosclerotic monkeys after dietary lipid lowering. BACKGROUND: Clinical trials suggest that hepatic hydroxymethylglutaryl coenzyme A reductase inhibitors may reduce the risk of coronary heart disease out of proportion to their effect on angiographically assessed lumen stenosis. METHODS: Thirty-two cynomolgus monkeys were fed an atherogenic diet for 2 years (progression phase) and then fed a lipid-lowering diet either containing (n = 14) or not containing (n = 18) pravastatin in the diet for an additional 2 years (treatment phase). As designed, total plasma cholesterol and high density lipoprotein concentrations did not differ between groups at the beginning of or during the treatment phase of the experiment (p > 0.05). RESULTS: Quantitative angiography revealed that coronary arteries of the pravastatin-treated monkeys dilated 10 +/- 3%, whereas those from untreated control monkeys constricted -2 +/- 2% in response to acetylcholine (p < 0.05). There were no treatment effects on plaque size of coronary arteries measured at the end of the treatment phase of the study (0.110 +/- 0.048 mm2 [untreated] vs. 0.125 +/- 0.051 mm2 [pravastatin]; p > 0.05) or on the amount of reduction in plaque size in common iliac arteries during the treatment phase of the study (48 +/- 5% [untreated] vs. 45 +/- 6% [pravastatin]; p > 0.05). However, histochemical analysis of the atherosclerotic lesions indicated that the arteries from pravastatin-treated monkeys had significantly fewer macrophages in the intima and media, less calcification and less neovascularization in the intima (p < 0.05). CONCLUSIONS: We conclude that compared with control monkeys, the arteries of pravastatin-treated monkeys had better dilator function and plaque characteristics more consistent with plaque stability than those of monkeys not receiving pravastatin. These beneficial arterial effects of pravastatin occurred independently of plasma lipoprotein concentrations and despite similar changes in plaque size between the groups.

Acetylcholine↗