Biomedical subjects

Ari D Brooks

Publications and source records attributed to Ari D Brooks.

5 recordsLinked to original sources

PubMed2006

A biplanar fluoroscopic approach for the measurement, modeling, and simulation of needle and soft-tissue interaction.

A methodology for modeling the needle and soft-tissue interaction during needle insertion is presented. The approach consists of the measurement of needle and tissue motion using a dual C-arm fluoroscopy system. Our dual C-arm fluoroscopy setup allows real time 3-D extraction of the displacement of implanted fiducials in the soft tissue during needle insertion to obtain the necessary parameters for accurate modeling of needle and soft-tissue interactions. The needle and implanted markers in the tissue are tracked during the insertion and withdrawal of the needle at speeds of 1.016 mm/s, 12.7 mm/s and 25.4 mm/s. Both image and force data are utilized to determine important parameters such as the approximate cutting force, puncture force, the local effective modulus (LEM) during puncture, and the relaxation of tissue. We have also validated the LEM computed from our finite element model with arbitrary needle puncture tasks. Based on these measurements, we developed a model for needle insertion and withdrawal that can be used to generate a 1-DOF force versus position profile that can be experienced by a user operating a haptic device. This profile was implemented on a 7-DOf haptic device designed in our laboratory.

Biopsy, Needle↗

PubMed2006

Prospective study of electrical impedance scanning for identifying young women at risk for breast cancer.

BACKGROUND: One way to improve the cost-benefit ratio for breast cancer screening in younger women is to identify those at high-risk of breast cancer and manage them in an optimal manner. The purpose of this study is to evaluate the sensitivity and specificity of Electrical Impedance Scanning (EIS) for identifying young women who are at risk for having breast cancer and should be followed with directed imaging technologies. METHODS: A prospective, observational, two-arm, multi-site clinical trial was performed on women aged 30-45 years. The 'Sensitivity Arm' included Clinical Breast Examinations (CBE) and EIS (T-Scan 2000ED) on 189 women prior to scheduled breast biopsy. The 'Specificity Arm' included 1361 asymptomatic women visiting clinics for routine annual well-woman examination. Sensitivity and specificity were determined. Relative probability for a woman with a positive EIS examination was computed and compared with other approaches commonly used to define 'high-risk' in this population. RESULTS: Fifty of 189 women in the Sensitivity arm had verified cancers, 19 of whom had positive EIS examination resulting in sensitivity of 38% (19/50). Of the 1361 women in the Specificity arm, 67 had positive EIS examination resulting in a specificity of 95% (1294/1361). The relative probability of a woman with a positive EIS examination was 7.68, which compares favorably with other established risk identifiers (e.g. two first-degree relatives with breast cancer or atypical ductal hyperplasia). CONCLUSION: EIS may have an important role as a screening tool for identifying young women that should be followed more closely with advanced imaging technologies for early detection of breast cancer.

Adult↗

PubMed2004

Monastrol, a prototype anti-cancer drug that inhibits a mitotic kinesin, induces rapid bursts of axonal outgrowth from cultured postmitotic neurons.

Terminally postmitotic neurons continue to express many of the kinesin-related proteins known to configure microtubules during mitosis. Drugs that inhibit these kinesins are being developed as anti-cancer agents with the hope that they will inhibit proliferation of tumor cells without having adverse effects on the nervous system. The prototype, termed monastrol, inhibits the kinesin known as Eg5, which is essential for maintaining separation of the half-spindles. Eg5 is also highly expressed in neurons, particularly during development. Exposure of cultured sympathetic neurons to monastrol for a few hours increased both the number and the growth rate of the axons. With additional time, the overall lengths of the axons were indistinguishable from controls. Sensory neurons showed a similar short-term increase in axonal growth rate. However, prolonged exposure resulted in shorter axons, suggesting that sensory neurons may be more sensitive to toxic effects of the drug. Nevertheless, the overall health of the cultures was still far more robust than cultures treated with taxol, a drug commonly used for anti-cancer therapy. On the basis of these results, we conclude that Eg5 normally generates forces that oppose axonal growth, presumably by partially suppressing the forward advance of microtubules. We speculate that local regulation of Eg5 could be a means by which neurons coordinate rapid bursts of axonal growth with appropriate environmental cues. The comparatively modest toxic effects on the neurons over time are a hopeful sign for clinicians interested in using anti-Eg5 drugs for cancer therapy.

Animals↗

PubMed2002

Evidence-based oncology project.

This article gives a brief overview of what can be gained from randomized clinical trials and the problems that are faced when examining the results of these trials. It also discusses the two essential elements driving the evidence-based oncology project, the first being the growth of MEDLINE and similar databases of medical publications, and the second being the concept of levels of evidence and quality.

Databases, Factual↗

PubMedDate not supplied

The value of laparoscopy in the management of ampullary, duodenal, and distal bile duct tumors.

Laparoscopy identifies radiologically occult advanced disease in patients with pancreatic adenocarcinoma. The value of laparoscopy in the management of peri-ampullary tumors was determined. One hundred forty-four patients with radiologically resectable nonpancreatic adenocarcinoma, periampullary tumors were identified from a prospective database between August 1993 and December 2000. Criteria for laparoscopic unresectability included histologically proved peritoneal or hepatic metastases, distant nodal involvement, arterial involvement, and local extension outside the resection field. Median age at operation was 70 years (range 31 to 87 years) and 56% of the patients were men. An adequate laparoscopy was performed in 134 cases (93%). Laparoscopy identified 13 patients (10%) with unresectable disease. Of 121 patients with laparoscopic resectable disease, 111 (92%) went on to subsequent resection; CT correctly predicted resectability in 82%. Laparoscopy spared 36% of unresectable patients a nontherapeutic laparotomy. Patients with resectable disease were treated by pancreaticoduodenectomy (n = 91, 76%), ampullectomy (n = 12, 10%), duodenal resection (n = 10, 9%), or bile duct excision (n = 6, 5%). The addition of diagnostic laparoscopy to dynamic CT scanning in this selected patient population identifies an additional 10% of patients with unresectable disease. We believe that laparoscopy should be used in a selective manner for preoperative staging of patients suspected of having nonpancreatic periampullary tumors.

Adult↗