Biomedical subjects

R J Jackman

Publications and source records attributed to R J Jackman.

At least 19 recordsLinked to original sources

PubMed2001

Stereotactic breast biopsy of nonpalpable lesions: determinants of ductal carcinoma in situ underestimation rates.

PURPOSE: To measure the effect of biopsy device, probe size, mammographic lesion type, lesion size, and number of samples obtained per lesion on the ductal carcinoma in situ (DCIS) underestimation rate. MATERIALS AND METHODS: Nonpalpable breast lesions at 16 institutions received a histologic diagnosis of DCIS after 14-gauge automated large-core biopsy in 373 lesions and after 14- or 11-gauge directional vacuum-assisted biopsy in 953 lesions. The presence of histopathologic invasive carcinoma was noted at subsequent surgical biopsy. RESULTS: By performing the chi(2) test, independent significant DCIS underestimation rates by biopsy device were 20.4% (76 of 373) of lesions diagnosed at large-core biopsy and 11.2% (107 of 953) of lesions diagnosed at vacuum-assisted biopsy (P <.001); by lesion type, 24.3% (35 of 144) of masses and 12.5% (148 of 1,182) of microcalcifications (P <.001); and by number of specimens per lesion, 17.5% (88 of 502) with 10 or fewer specimens and 11.5% (92 of 799) with greater than 10 (P <.02). DCIS underestimations increased with lesion size. CONCLUSION: DCIS underestimations were 1.9 times more frequent with masses than with calcifications, 1.8 times more frequent with large-core biopsy than with vacuum-assisted biopsy, and 1.5 times more frequent with 10 or fewer specimens per lesion than with more than 10 specimens per lesion.

Axilla↗

PubMed2000

Fabrication of topologically complex three-dimensional microfluidic systems in PDMS by rapid prototyping.

This paper describes a procedure for making topologically complex three-dimensional microfluidic channel systems in poly(dimethylsiloxane) (PDMS). This procedure is called the "membrane sandwich" method to suggest the structure of the final system: a thin membrane having channel structures molded on each face (and with connections between the faces) sandwiched between two thicker, flat slabs that provide structural support. Two "masters" are fabricated by rapid prototyping using two-level photolithography and replica molding. They are aligned face to face, under pressure, with PDMS prepolymer between them. The PDMS is cured thermally. The masters have complementary alignment tracks, so registration is straightforward. The resulting, thin PDMS membrane can be transferred and sealed to another membrane or slab of PDMS by a sequence of steps in which the two masters are removed one at a time; these steps take place without distortion of the features. This method can fabricate a membrane containing a channel that crosses over and under itself, but does not intersect itself and, therefore, can be fabricated in the form of any knot. It follows that this method can generate topologically complex microfluidic systems; this capability is demonstrated by the fabrication of a "basketweave" structure. By filling the channels and removing the membrane, complex microstructures can be made. Stacking and sealing more than one membrane allows even more complicated geometries than are possible in one membrane. A square coiled channel that surrounds, but does not connect to, a straight channel illustrates this type of complexity.

Dimethylpolysiloxanes↗

PubMed2000

Mammographic abnormalities caused by percutaneous stereotactic biopsy of histologically benign lesions evident on follow-up mammograms.

OBJECTIVE: The purpose of our study was to evaluate how often a mammographic abnormality thought to be produced by the biopsy procedure was evident on the initial follow-up mammogram after percutaneous biopsy of impalpable histologically benign lesions. We compared three stereotactic percutaneous biopsy methods. CONCLUSION: A mammographic density seen well only in the projection parallel to the biopsy needle tract was evident in 2% (5/226) of the lesions for which 11-gauge directional vacuum-assisted biopsy was used, 0% (0/96) of the lesions for which 14-gauge directional vacuum-assisted biopsy was used, and 0% (0/422) of the lesions for which 14-gauge automated large-core biopsy was used. No mammographic abnormalities assessed as BI-RADS categories 3, 4, or 5 (according to the American College of Radiology's Breast Imaging Reporting and Data System) and thought to be produced by the biopsy procedure were evident after any of the biopsy methods.

Biopsy, Needle↗

PubMed1999

Stereotactic, automated, large-core needle biopsy of nonpalpable breast lesions: false-negative and histologic underestimation rates after long-term follow-up.

PURPOSE: To determine the rate and causes of false-negative findings and histologic underestimates at stereotactic biopsy of nonpalpable breast lesions. MATERIALS AND METHODS: Stereotactic, 14-gauge, automated, large-core needle biopsy (LCNB) was performed in 483 consecutive nonpalpable breast lesions. Excision was advised for the 143 carcinomas, 25 atypical ductal hyperplasia (ADH) lesions, and five radial scars. Mammographic follow-up was advised for the benign lesions without a repeat biopsy. RESULTS: Of the 310 benign lesions, 259 underwent mammographic follow-up at 6-85 months (median, 55 months) without repeat biopsy, 48 underwent repeat biopsy and three were lost to follow-up. On the basis of the histologic diagnosis of carcinoma at surgical biopsy, diagnosis with LCNB was not correct (i.e., disease was underestimated at histologic examination) in 14 (58%) of 24 ADH lesions and two (40%) of five radial scars. Two (1.2%) of 161 lesions with a final diagnosis of carcinoma were benign at LCNB but malignant at repeat biopsy (i.e., false-negative findings at LCNB). Repeat biopsy was prompted by mammographic progression at 6 and 18 months after LCNB. CONCLUSION: The false-negative rate with LCNB was 1.2% in this study and 4.0% in the literature. The presence of carcinoma in ADH and radial scar lesions was often underestimated.

Adult↗

PubMed1998

Percutaneous removal of benign mammographic lesions: comparison of automated large-core and directional vacuum-assisted stereotactic biopsy techniques.

OBJECTIVE: The purpose of our study was to evaluate how often histologically benign lesions were completely removed as shown by the initial mammogram after biopsy. We compared three percutaneous biopsy techniques. MATERIALS AND METHODS: Retrospective review was performed on 1206 consecutive impalpable breast lesions having percutaneous stereotactic biopsies done on a prone biopsy table using 14-gauge automated large-core needles (n = 721); 14-gauge directional vacuum-assisted probes (n = 192); and 11-gauge directional vacuum-assisted probes (n = 293). Lesions that were histologically benign and that did not have subsequent surgical excision had mammographic follow-up. The 667 initial mammograms after biopsy (advised to be done at 6 or 12 months and accomplished at 1-53 months [median, 7 months] after biopsy) were reviewed to see if the lesions were no longer apparent. RESULTS: The lesion was absent in 9% (40/422) of lesions for which 14-gauge large-core biopsy was used, 22% (21/95) of lesions for which 14-gauge vacuum-assisted biopsy was used, and 64% (96/150) of lesions for which 11-gauge vacuum-assisted biopsy was used (p < .0001). No mammographic pseudolesions were created by the biopsy. No clinically significant complications occurred. CONCLUSION: The lesion was more often completely removed with directional vacuum-assisted biopsy than with automated large-core biopsy and more often completely removed with 11-gauge probes than with 14-gauge probes.

Biopsy, Needle↗

PubMed1997

A miniaturized arrayed assay format for detecting small molecule-protein interactions in cells.

BACKGROUND: Two complementary approaches to studying the cellular function of proteins involve alteration of function either by mutating protein-encoding genes or by binding a small molecule to the protein. A mutagen can generate millions of genetic mutations; correspondingly, split-pool synthesis can generate millions of unique ligands attached to individual beads. Genetic screening of mutations is relatively straightforward but, in contrast, split-pool synthesis presents a challenge to current methods of screening for compounds that alter protein function. The methods used to screen natural products are not feasible for large libraries composed of covalently immobilized compounds on synthesis beads. The sheer number of compounds synthesized by split-pool synthesis, and the small quantity of individual compound attached to each bead require assay miniaturization for efficient screening. RESULTS: We present a miniaturized cell-based technique for the screening of ligands prepared by split-pool synthesis. Spatially defined droplets with uniform volumes of approximately 50-150 nanoliters (depending on well dimensions) are arrayed on plastic devices prepared using a combination of photolithography and polymer molding. Using this microtechnology, approximately 6,500 assays using either yeast cells or mammalian tissue culture can be performed within the dimensions of a standard 10 cm petri dish. We demonstrate that the biological effect of a small molecule prepared by split-pool synthesis can be detected in this format following its photorelease from a bead. CONCLUSIONS: The miniaturized format described here allows uniformly sized nanodroplets to be arrayed on plastic devices. The design is amenable to a large number of biological assays and the spatially arrayed format ensures uniform and controlled ligand concentrations and should facilitate automation of assays. The screening method presented here provides an efficient means of rapidly screening large numbers of ligands made by split-pool synthesis in both yeast and mammalian cells.

Animals↗

PubMed1997

Atypical ductal hyperplasia diagnosed at stereotactic breast biopsy: improved reliability with 14-gauge, directional, vacuum-assisted biopsy.

PURPOSE: To compare histologic findings of atypical ductal hyperplasia (ADH) at 14-gauge, directional, vacuum-assisted breast biopsy (hereafter, vacuum-assisted biopsy) and at 14-gauge, automated, large-core breast biopsy (hereafter, large-core biopsy) with findings at histologic examination after surgical biopsy. MATERIALS AND METHODS: Nonpalpable breast lesions were diagnosed as ADH at histologic examination after vacuum-assisted biopsy in 88 lesions in seven institutions and after large-core biopsy in 55 previously reported lesions. Histologic findings at subsequent surgical biopsy were compared for the presence of carcinoma. RESULTS: On the basis of histologic findings of carcinoma at surgical biopsy, the diagnosis of ADH was not correct in 26 (48%) of 54 lesions sampled at large-core biopsy and in 13 (18%) of 74 lesions sampled at vacuum-assisted biopsy (Fisher exact test, P < .0004). More tissue specimens were obtained at vacuum-assisted biopsy (mean, 15.8 specimens) than at large-core biopsy (mean, 9.7 specimens). Individual specimens were twice as large at vacuum-assisted biopsy (mean, 34 mg) as at large-core biopsy (mean, 17 mg) (previously reported). CONCLUSION: ADH was diagnosed 2.7 times more reliably at vacuum-assisted biopsy than at large-core biopsy (with no increase in complications) with most of the improvement as a result of acquisition of more than 10 specimens per lesion, but carcinoma was sufficiently underestimated with both methods to necessitate surgical biopsy.

Biopsy, Needle↗

PubMed1997

Needle-localized breast biopsy: why do we fail?

PURPOSE: To determine what factors are associated with unsuccessful needle-localized breast biopsy (NLBB). MATERIALS AND METHODS: Findings in 280 consecutive nonpalpable breast lesions in 262 women (age range, 27-87 years; mean age, 55 years) who underwent nonstereotactic, mammographically guided, standardized NLBB were retrospectively analyzed according to mammographic lesion type, lesion size, number of lesions per breast, needle type, proximity of needle to lesion, radiologist, specimen size, surgeon, and histologic findings. RESULTS: Biopsy failed in seven (2.5%) of 280 lesions. Failures were related to lesion type, lesion size, number of lesions per breast, accuracy of needle placement, and volume of tissue removed. Removal of more than one tissue specimen converted failure to success in 14 (67%) of 21 initially missed lesions, all microcalcifications. CONCLUSION: Unsuccessful NLBB was more likely with two lesions per breast, small lesions, small specimens, and microcalcifications. Piercing such lesions with the localizing needle led to successful biopsy. Removal of more tissue was helpful with missed microcalcifications.

Adult↗

PubMed1995

Fabrication of submicrometer features on curved substrates by microcontact printing.

Microcontact printing (mu CP) has been used to produce patterned self-assembled monolayers (SAMs) with submicrometer features on curved substrates with radii of curvature as small as 25 micrometers. Wet-chemical etching that uses the patterned SAMs as resists transfers the patterns formed by mu CP into gold. At present, there is no comparable method for microfabrication on curved surfaces.

Chemistry, Physical↗

PubMed1994

Stereotaxic large-core needle biopsy of 450 nonpalpable breast lesions with surgical correlation in lesions with cancer or atypical hyperplasia.

PURPOSE: To determine whether histologic findings of cancer or atypical hyperplasia at large-core needle biopsy (LCNB) of nonpalpable breast lesions match histologic findings at excision. MATERIALS AND METHODS: Stereotaxic LCNB was performed with an automated prone unit, biopsy gun, and 14-gauge cutting needles in 450 nonpalpable breast lesions. Lesions classified as carcinoma or atypical ductal hyperplasia (ADH) at histologic examination after LCNB were excised. A pathologist retrospectively compared core and excisional histologic findings. RESULTS: Histologic comparison was performed in 116 of 135 carcinomas after LCNB. Histologic findings were concordant in 99 carcinomas. Partial discordance in 17 carcinomas led to an additional surgical procedure in one case. Histologic comparison was performed in 16 of 19 ADHs diagnosed with LCNB. Histologic findings were concordant in five and discordant in 11 ADHs. CONCLUSION: LCNB findings of carcinoma are accurate and allow definitive therapeutic surgery, including mastectomy. LCNB findings of ADH are inaccurate, and excisional biopsy is necessary.

Biopsy, Needle↗

PubMed1994

Percutaneous large-core breast biopsy: a multi-institutional study.

PURPOSE: To assess the reliability and reproducibility of automated large-core breast biopsy. MATERIALS AND METHODS: A consortium of 20 institutions reported, in a standardized fashion, their core breast biopsy data. All biopsies were performed with "long-throw" (2.3-cm) automated core biopsy devices fitted with 14-gauge needles. Needle guidance was accomplished by means of either a dedicated, stereotaxic device, in which the patient lies in the prone position, or high-frequency electronically focused ultrasound equipment. RESULTS: The data in 6,152 lesions were gathered. Clinical or surgical follow-up was available in 3,765 lesions; 1,363 of these lesions were subsequently surgically excised, and the core histologic study showed cancer in 910 lesions, mammary intraepithelial neoplasia in 173 lesions, and benign disease in 280 lesions. In these 280 lesions, there were 15 false-negative core biopsies. CONCLUSION: The data show that percutaneous large-core breast biopsy is a reproducible and reliable alternative to surgical biopsy.

Biopsy, Needle↗

PubMed1989

Needle biopsy of the liver. A critique of four currently available methods.

There are currently four needle biopsy methods for obtaining tissue from patients with possible diffuse liver disease or cancer. These include percutaneous blind needle biopsy, a visually guided needle biopsy at laparoscopy, guided fine-needle biopsies with ultrasonography or computed tomography, and the transvenous liver biopsy. We and others have found the guided fine-needle biopsy technique to be safe, relatively cheap, and highly accurate in the diagnosis of liver cancer. Blind percutaneous biopsy should be reserved for patients with possible diffuse, noncancerous, liver disease. Guided biopsies at laparoscopy can be done if the other two methods fail to give a tissue diagnosis. The transvenous approach is useful in patients with a coagulation disorder.

Biopsy, Needle↗

PubMed1984

Outpatient needle biopsy of the lung: its safety and utility.

Four hundred forty-seven needle biopsies of the lung were carried out on 348 patients in a nonhospital outpatient setting. There were no fatalities or serious complications. A reliable working diagnosis was obtained in 74% of patients (86% true positive for malignancy). Diagnostic thoracotomy was avoided in 31%, and the diagnostic interval was shortened in most. Impressive economic benefits resulted. Careful postbiopsy evaluation revealed pneumothorax in 41% of patients, with 10% requiring chest tube drainage, usually on an ambulatory basis. With management of the infrequent complications by the radiologist, outpatient needle biopsy of the lung can be safe, reliable, and highly cost effective.

Ambulatory Care↗

PubMed1974