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Biomedical subjects

Susan Hall

Publications and source records attributed to Susan Hall.

11 recordsLinked to original sources
PubMed2007

Anatomy of the distal biceps brachii tendon and its clinical relevance.

Rupture of the distal biceps tendon is a relatively uncommon injury. Different methods have been described for its surgical repair. According to published reports, current surgical techniques result in decreased strength and endurance of upper extremity functions requiring supination and flexion. In our anatomic study of 74 cadaveric elbows, we observed that the distal biceps tendon spirals in a predictable manner and has a complex fiber arrangement. Successful surgical repair of a ruptured distal biceps tendon should be predicated on an understanding of the tendon anatomy, but current surgical techniques do not take into account the salient anatomic features of the distal biceps tendon. To our knowledge, there is no description in the surgical literature of the fiber arrangement of the distal biceps tendon. We provide a basis for developing an anatomically accurate protocol for repairing a distal biceps tendon rupture.

Aged↗
PubMed2006

Intracellular localization of varicella-zoster virus ORF39 protein and its functional relationship to glycoprotein K.

Varicella-zoster virus (VZV) encodes two multiply inserted membrane proteins, open reading frame (ORF) 39 protein (ORF39p) and glycoprotein K (gK). The HSV-1 homologs of these proteins are believed to act in conjunction with each other during viral egress and cell-cell fusion, and they directly influence each other's intracellular trafficking. However, ORF39p and VZV gK have received very limited study largely due to difficulties in producing antibodies to these highly hydrophobic proteins. To overcome this obstacle, we introduced epitope tags into both ORF39p and gK and examined their intracellular distributions in transfected and infected cells. Our data demonstrate that both ORF39p and gK accumulate predominately in the ER of cultured cells when expressed in the absence of other VZV proteins or when coexpressed in isolation from other VZV proteins. Therefore, the transport of VZV ORF39p and gK does not exhibit the functional interdependence seen in their HSV-1 homologs. However, during infection, the primary distributions of ORF39p and gK shift from the ER to the Golgi, and they are also found in the plasma membrane indicating that their intracellular trafficking during infection depends on other VZV-encoded proteins. During infection, ORF39p and gK tightly colocalize with VZV envelope glycoproteins B, E and H; however, the coexpression of ORF39p or gK with other individual viral glycoproteins is insufficient to alter the transport of either ORF39p or gK.

Amino Acid Sequence↗
PubMed2006

Interactions between retinoic acid, nerve growth factor and sonic hedgehog signalling pathways in neurite outgrowth.

Many studies have shown a role of retinoid signalling in neurite outgrowth in vitro, and that the retinoic acid receptor (RAR) beta2 is critical for this process. We show here that RARbeta2 is expressed predominantly in dorsal root ganglia (DRG) neuronal subtypes that express neurofilament (NF) 200 and calcitonin gene-related peptide (CGRP), and that these neurons extend neurites in response to RA. We demonstrate that retinoid signalling has a role in neurite outgrowth in vivo, by showing that in a peripheral nerve crush model there is less neurite outgrowth from RARbeta null DRG compared to wild-type. We identify sonic hedgehog (Shh) as a downstream target of the RARbeta2 signalling pathway as it is expressed in the injured DRG of wild-type but not RARbeta null mice. This regulation is direct as when RARbeta2 is overexpressed in adult motoneurons Shh is induced in them. Finally we show that Shh alone cannot induce neurite outgrowth but potentiates RARbeta2 signalling in this process.

Animals↗
PubMed2006

Extensive neuroprotection by choroid plexus transplants in excitotoxin lesioned monkeys.

Huntington's disease (HD) results from degeneration of striatal neurons. Choroid plexus (CP) cells secrete neurotrophic factors, and CP transplants are neuroprotective in rat models of HD. To determine if similar neuroprotective effects could be obtained in primates, porcine CP was encapsulated in alginate capsules. PCR confirmed that the CP cells expressed transthyretin and immunocytochemistry demonstrated typical ZO-1 and tubulin staining. In vitro, CP conditioned media enhanced the survival and preserved neurite number and length on serum deprived neurons. Cynomolgus primates were transplanted with CP-loaded capsules into the caudate and putamen followed by quinolinic acid (QA) lesions 1 week later. Control monkeys received empty capsules plus QA. Choroid plexus transplants significantly protected striatal neurons as revealed by stereological counts of NeuN-positive neurons (8% loss vs. 43% in controls) and striatum volume (10% decrease vs. 40% in controls). These data indicate that CP transplants might be useful for preventing the degeneration of neurons in HD.

Animals↗
PubMed2006

Pulsed radiofrequency applied to dorsal root ganglia causes a selective increase in ATF3 in small neurons.

BACKGROUND: This is a "proof of concept study" to test the hypothesis that pulsed radiofrequency, PRF, produces cell stress at the primary afferent level without signs of overt thermal damage. We assumed that cell stress would result in impairment of normal function, and used the expression of activating transcription factor 3, ATF3, as an indicator of cellular "stress". METHODS: PRF (20 ms of 500-kHz RF pulses, delivered at a rate of 2 Hz; maximum temperature 42 degrees C) was delivered either to the sciatic nerve of adult rats in mid thigh, or to the L4 anterior primary ramus just distal to the intervertebral foramen. Controls were sham-operated or L4 axotomised. All tissues were examined 14 days after surgery. The percentage of CGRP- or ATF3-positive DRG neuronal somata was calculated using image analysis software (SigmaScan Pro 4). RESULTS: ATF3 expression was upregulated in L4 DRG neuronal cell bodies, irrespective of their size, after axotomy. It was also upregulated significantly (p<0.002) and selectively, in small and medium calibre L4 DRG neurons, when PRF was applied close to the DRG just distal to the intervertebral foramen. PRF did not produce any obvious cellular changes in the nerve or L4 DRG neurons when applied to the sciatic nerve in mid-thigh. CONCLUSION: PRF has a biological effect, unlikely to be related to overt thermal damage. It appears to be selective in that it targets the group of neurons whose axons are the small diameter C and Adelta nociceptive fibres.

Activating Transcription Factor 3↗
PubMed2004

Stabilisation of cables of fibronectin with micromolar concentrations of copper: in vitro cell substrate properties.

We have previously described the production of large cables of fibronectin, a large extracellular matrix cell adhesion glycoprotein, which has a potential application in tissue engineering. Here we have stabilised these cables for longer survival and looked at their ultrastructural cell-substrate behaviour in vitro. Dissolution experiments showed that low concentrations of copper not only caused significant material stabilisation but left pores which could promote cell ingrowth, as we have previously reported with Fn-mats. Indeed, the greatest amount of cell ingrowth was observed for copper treated cables. Immunostaining showed S-100(+) multi-layers of cells around the edge of cables while ultrastructural analysis confirmed the presence of a mixture of fibroblasts and bipolar cells associated with fragments of basal lamina, which is a Schwann cell phenotype. Interestingly, the outermost layers of cells consisted of S-100(-) cells, presumed fibroblasts, apparently 'capping' the Schwann cells. Toxicity tests revealed that Schwann cells were only able to grow at the lowest concentration of copper used (1microM) while fibroblasts grew at all concentrations tested. These results could be used to design biomaterials with optimum properties for promoting cellular ingrowth and survival in tissue engineered grafts which may be used to improve peripheral nerve repair.

Animals↗
PubMed2004

Influence of pelvis rotation styles on baseball pitching mechanics.

Efficient, sequential timing is essential for upper level pitching. Interestingly, pitchers vary considerably in timing related elements of pitching style including pelvis rotation, arm cocking, stride leg behaviour, and pitch delivery time. The purpose of this study was to determine whether relationships exist among these elements by examining the overall style of pitchers exhibiting different pelvis rotation patterns. Pitching styles were defined by pelvis orientation at the instant of stride foot contact. Pitchers demonstrating a pelvis orientation greater than 30 degrees were designated as 'early rotators', while pitchers demonstrating a pelvis orientation less than 30 degrees were designated as 'late rotators'. Kinematic and temporal differences were associated with the two styles. During the arm cocking phase, early rotators showed significantly greater shoulder external rotation at the instant of stride foot contact, earlier occurrence of maximum pelvis rotation angular velocity, and shorter time taken to complete the phase. However, by the instant of maximum shoulder external rotation, early and late rotators appeared remarkably similar as no significant difference occurred in pelvis and arm orientations. Therefore, it appears that early and late rotators used different methods to achieve similar results, including throwing velocity. Significant differences in throwing arm kinetics were also found for 10 of the 11 measures in the study. As the pelvis assumed a more open position at stride foot contact, maximum kinetic values were found to both decrease in magnitude and occur at an earlier time within the pitch.

Adolescent↗
PubMed2002

Making epidemiologic studies responsive to the needs of participants and communities: the Carolina Breast Cancer Study experience.

In this report, we present the results of surveys administered to participants and nonparticipants in the Carolina Breast Cancer Study (CBCS). Surveys and structured interviews were administered to determine women's concerns regarding participation in research studies, access to health care, and beliefs regarding causes of breast cancer. Survey results showed the highest concern for the growing number of women diagnosed with breast cancer in North Carolina and potential environmental agents that may cause breast cancer. Negative responses were noted for time constraints related to participation and lack of familiarity with epidemiologic research; another concern noted was the lack of centralized information regarding breast cancer treatment. These issues were addressed by (1) developing a web site that provided background information about the CBCS, summaries of published study results, and information about the etiology of breast cancer; and (2) creating a statewide, comprehensive breast cancer resource directory for women who need information about breast cancer diagnosis, treatment, and support. These two projects were carried out in collaboration with breast cancer advocates, and demonstrate the important role that advocates can play in making epidemiologic research more responsive to the needs of communities.

Adult↗
PubMed2002

Second varicella infections: are they more common than previously thought?

OBJECTIVE: To describe the epidemiology and clinical characteristics of varicella reinfections reported to a surveillance project. METHODS: We investigated varicella cases reported to a surveillance project between January 1, 1995, and December 31, 1999--with more extensive investigation of cases reporting previous varicella with onset between January 1, 1998, and September 30, 1998--to provide a more detailed description of first and second varicella infections. A simple decision tree was used to assess the likelihood that reported first and second infections were varicella. RESULTS: Among varicella cases reported to the surveillance project, 4.5% of cases in 1995 and 13.3% of cases in 1999 reported previous varicella. More than 95% of first infections were physician diagnosed, epidemiologically linked to another case, or had a rash description consistent with varicella; the same was true for reported second infections. People who reported reinfections were generally healthy. There was a family history of repeat infections in 45% of people who reported reinfections. CONCLUSIONS: Clinical varicella reinfections may occur more commonly than previously thought. Additional studies of the predictive value of a positive varicella history and laboratory studies of reported reinfections are indicated to guide varicella vaccination policy.

Adolescent↗
PubMedDate not supplied

Childbirth anger.

Explore the source record for details and available documents.

Anger↗