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Biomedical subjects

A Sands

Publications and source records attributed to A Sands.

15 recordsLinked to original sources
PubMed1998

Effect of variations in calcaneocuboid fusion technique on kinematics of the normal hindfoot.

Calcaneocuboid fusion with lengthening of the lateral column of the foot has been advocated as a method of treating flatfoot deformity. This study was designed to determine how the length of the lateral column chosen or the position of the foot selected when performing this fusion affect hindfoot kinematics in normal cadaver feet. An electromagnetic tracking system was used to monitor the positions of the talus, calcaneus, navicular, and cuboid while the intact cadaver feet were moved passively and then under reproducible loads. Calcaneocuboid fusion was then performed on these feet first with the feet in neutral position and the lateral column of normal length, then lengthened 10 mm or shortened 5 mm, and then with the lateral column lengthened 10 mm and the feet positioned in plantar flexion and eversion or dorsiflexion and inversion. Kinematic measurements were made at each stage using the same loads. Fusing the calcaneocuboid joint with lengthening or shortening the lateral column and the feet in neutral position did not affect hindfoot joint motion compared with intact. Changing the position of the foot for fusion, however, resulted in significant decreases in motion in the talocalcaneal and talonavicular joints. Tibiotalar joint motion was unaffected. This study, therefore, demonstrates that when fusing the calcaneocuboid joint, attention should be paid to maintaining a neutral position of the foot.

Arthrodesis↗
PubMed1998

Clinical and functional outcomes of internal fixation of displaced pilon fractures.

The clinical and functional outcomes for patients treated with open reduction and plate fixation of displaced tibial pilon fractures were determined. A retrospective search of the authors' trauma database was conducted for AO and Orthopaedic Trauma Association Code 43 injuries (pilon fractures) in adults 18 years or older who were treated between December 1988 and December 1992. The group of 64 patients who required open reduction and internal fixation to treat their fractures make up the primary cohort for this analysis. Twenty of these cases required no fibular fixation; the remainder were mostly fixed with 1/3 tubular or 3.5-mm compression plates. Tibial fixation was done using most commonly 3.5-mm cloverleaf plates, 1/3 tubular plates, or both. Of the 64 patients treated with open reduction and internal replacement, four (5%) patients had deep infection develop. Two (7%) of 14 patients had open fractures, and two (4%) of 50 patients had closed fractures. Three of these four patients smoked tobacco products; one was also an intravenous drug abuser. Staphylococcus aureus was the organism in two cases; Enterobacter, in the other two. The infection was controlled with a free flap in two cases, with antibiotics and wound debridement in one and with an arthrodesis in one. Thirty of the 64 patients completed the Short Form-36; two of these patients had bilateral fractures. The study group had significant differences in general health perceptions, physical function, physical role function, emotional role function, social and mental function, and pain and energy levels when compared with age matched population data and patients with tibial plateau fractures. The effect of other injuries on these functional status results cannot be determined specifically.

Adolescent↗
PubMed1997

Embryonic lethality and radiation hypersensitivity mediated by Rad51 in mice lacking Brca2.

Inherited mutations in the human BRCA2 gene cause about half of the cases of early-onset breast cancer. The embryonic expression pattern of the mouse Brca2 gene is now defined and an interaction identified of the Brca2 protein with the DNA-repair protein Rad51. Developmental arrest in Brca2-deficient embryos, their radiation sensitivity, and the association of Brca2 with Rad51 indicate that Brca2 may be an essential cofactor in the Rad51-dependent DNA repair of double-strand breaks, thereby explaining the tumour-suppressor function of Brca2.

3T3 Cells↗
PubMed1996

Substance use in an inner-city family planning population.

OBJECTIVE: To determine the prevalence of drug and alcohol use in an inner-city family planning population and to identify variables associated with a positive urine screen. STUDY DESIGN: We conducted blind urine drug and alcohol screening in 309 women attending an inner-city hospital family planning clinic. RESULTS: The prevalence of a positive urine drug and/or alcohol screen was 15.5% (48/309). Specific substance positivity rates were: marijuana 9.4%, cocaine 4.9%, alcohol 1.3%, benzodiazepines 1.0%, opiates 1.0% and amphetamines 0.3%. After controlling for other independent variables, increased age was the only predictor of having a positive drug and/or alcohol screen, while increased age and a history of a sexually transmitted disease predicted the use of drugs other than marijuana or alcohol alone. CONCLUSIONS: Our findings support the concept that substance use histories and urine drug screening should be considered in patients seeking family planning services. This strategy can lead to counseling and treatment for a population seeking preventive care that might otherwise not be identified.

Adult↗
PubMed1994

Gene-targeting and the p53 tumor-suppressor gene.

Gene-targeting techniques are now frequently applied to embryonic stem (ES) cells to introduce mutations of endogenous genes in mice. Modifications introduced into tumor-suppressor genes by this technology have produced mice and cell lines with unique tumorigenic and growth characteristics, respectively. A number of strategies have been developed to enhance the efficiency of homologous recombination between targeting vectors and endogenous genes. This review describes recent advances in the techniques used to construct mice with a variety of genetic alterations. In addition, an application of gene-targeting is illustrated in the study of a class of genes with tumor-suppressor function. Recent findings from experiments using gene targeted mice to study the p53 tumor-suppressor gene are discussed and the potential of gene-targeting for the discovery and study of novel tumor-suppressor genes are explored.

Animals↗
PubMed1989

Development of a bacteria-independent model of the multiple organ failure syndrome.

Criteria that allow definition of the multiple organ failure syndrome include pulmonary, hepatic, renal, and gut barrier dysfunction along with characteristic histopathologic changes. It has been difficult to study multiple organ failure due to lack of a satisfactory experimental model that would reproduce the pathophysiologic and histopathologic characteristics, would be stable enough to allow study over several days, and would be free of exogenous primary bacterial infection. We have studied pathophysiologic and histopathologic alterations in a potential model of multiple organ failure. Wistar rats received one of the following solutions by intraperitoneal injection: 4 mL of saline, 4 mL of mineral oil, or 1 mg per gram of body weight of zymosan A in 4 mL of mineral oil. Animals that received zymosan developed hypoxia, decreased creatinine clearance, and changes in hepatic microsomal cytochrome P450 content and aniline hydroxylase activity. Bacterial translocation occurred in the zymosan group. The lungs, liver, and kidneys of the animals that received zymosan exhibited histopathologic changes. We conclude that this model fulfills our criteria for a model of multiple organ failure.

Animals↗
PubMed1989

Management of selected problems in revision knee arthroplasty.

In discussing revision arthroplasty, understanding the failure mode is essential to success. In general there are five major categories that one must address in assessing the failed knee replacement: Infection, mechanical problems, extensor mechanism dysfunction, fractures adjacent to the components, and skin problems. These five areas are discussed in this article.

Biomechanical Phenomena↗
PubMedDate not supplied

Multiple intrapulmonary arteriovenous fistulas in childhood.

Pulmonary arteriovenous fistulas (AVFs) are a rare but recognized cause of cyanosis in childhood. Lesions may be acquired as in hepatopulmonary syndrome or they may be congenital, particularly in association with certain multisystem disorders. Large fistulas are more common than multiple small connections. Two cases. both boys, presenting in the first decade of life are described. "Bubble" echocardiography was the most telling investigation and strongly suggested the presence of AVFs in both cases. Each patient then underwent cardiac catheterization, which demonstrated normal pulmonary artery pressure and diffuse pulmonary telangiectasis. Both patients were treated effectively with nifedipine and continue with this mode of therapy.

Abnormalities, Multiple↗
PubMedDate not supplied

Chemosensitivity of squamous cell carcinoma grown in implantable chambers.

This study was motivated by the need to develop new methods to predict tumor response to chemotherapeutic agents. Using implantable cell-growth chambers, squamous carcinoma cells from head and neck tumors were xenografted into the peritoneal cavity of immunocompetent rats. Animals were divided into control and treatment groups. The treatment groups received intravenous cisplatin (CDDP) or 5-fluorouracil (5-FU) v normal saline solution for the control. Animals from each group were randomly selected and killed on days 3, 5, and 7 postimplantation. The chambers were retrieved, the media aspirated, and cells counted. Exponential growth curves were derived for the control and treatment groups. Statistically significant growth inhibition was observed for both treatment arms, compared with controls. This method of chemosensitivity testing proved to be inexpensive and reliable, and demonstrated tumor cell killing by 5-FU and CDDP.

Animals↗