Fatigue of immature baboon cortical bone.

Strain-controlled uniaxial fatigue and monotonic tensile tests were conducted on turned femoral cortical bone specimens obtained from baboons at various ages of maturity. Fatigue loading produced a progressive loss in stiffness and an increase in hysteresis prior to failure, indicating that immature primate cortical bone responds to repeated loading in a fashion similar to that previously observed for adult human cortical bone. Bone fatigue resistance under this strain controlled testing decreased during maturation. Maturation was also associated with an increase in bone dry density, ash fraction and elastic modulus. The higher elastic modulus of more mature bone meant that these specimens were subjected to higher stress levels during testing than more immature bone specimens. Anatomical regions along the femoral shaft exhibited differences in strength and fatigue resistance.

Magnetic field dependence of spin-lattice relaxation enhancement using piperidinyl nitroxyl spin-labels.

We examined the magnetic resonance properties of 12 paramagnetic piperidinyl nitroxyls in water and plasma solutions. Paramagnetic contributions to proton relaxation times were measured using 10.7 and 100 MHz spectrometers. Proton relaxation enhancement from nitroxyls increased with ascending molecular weight, in plasma solutions versus equimolar aqueous solutions, and with measurements at 10.7 MHz compared to 100 MHz. Relaxation rates were observed to approximately double at 10.7 MHz compared to 100 MHz and from water to plasma solutions. The data indicate that proton spin-lattice relaxation enhancement is magnetic field-dependent, and increases using nitroxyls of large molecular weight and with chemical substitutents that increase the microviscosity of solvent water molecules. The development of nitroxyls for diagnostic MRI will be aided by understanding these in vitro physical characteristics and trends.

Stereotaxic core breast biopsy: value in providing tissue for flow cytometric analysis.

OBJECTIVE: Stereotaxic core biopsy provides intact samples of breast tissue for accurate histologic analysis. We conducted a study to determine if prognostic data could also be successfully derived from such core samples and how the data correlate with surgical biopsy. MATERIALS AND METHODS: Both core and surgical breast biopsies from 135 patients were processed under a uniform flow cytometry protocol. Samples were coded and then randomly processed at an outside flow cytometer and interpreted by an independent pathologist; the code was broken and patients' results correlated only after all samples were completely analyzed. RESULTS: Core breast biopsy provides intact tissue that can be successfully processed by a flow cytometer, even after being embedded in paraffin for initial histologic analysis. Larger cores (14 gauge) had fewer insufficient samples, as recorded on ploidy histograms. Although ploidy may reflect the underlying aggressiveness of a lesion and assist in evaluating breast cancer, surgical-pathologic correlation with stereotaxic biopsy indicated, as has been confirmed in other studies, considerable overlap of different ploidy types between benign and malignant conditions. There was no correlation between mammographic presentation and ploidy or S-phase fractions. CONCLUSION: Stereotaxic large-core biopsy can enable accurate histologic diagnosis of breast disease and furnish sufficient tissue for flow cytometric measurements of ploidy and S-phase fractions, even at an interval following paraffinization. Such prognostic information aids in planning of adjuvant therapy, allows flexibility should surgery fail to provide enough tissue for DNA study, and helps radiologists further market stereotaxic biopsy to clinicians.

Gorlin's syndrome with associated odontogenic cysts.

Multiple maxillary and mandibular cysts are principle features of basal cell nevus syndrome (Gorlin-Goltz). We present cases from an affected family in which magnetic resonance imaging (MRI) was helpful in evaluation of the cystic lesions. A middle ear anomaly was identified which may represent an additional abnormality associated with the syndrome.

Nonpalpable breast lesions: stereotactic automated large-core biopsies.

One hundred two patients with mammographically suspicious, nonpalpable lesions underwent stereotactic breast biopsy with a biopsy gun and an automated 14-gauge cutting needle. After biopsy, a localization wire was placed and surgical biopsy performed. There was agreement of the histologic results from the gun biopsy and the surgical biopsy specimens in 98 cases (96%), including 22 of 23 carcinomas (96%) (kappa = 0.936). The gun biopsy yielded findings that led to the correct diagnosis in two cases involving lesions that were missed at surgical biopsy; two lesions found at surgery were missed at gun biopsy. The results of this study suggest that the use of 14-gauge needles improves agreement between surgical and needle core biopsy findings and that stereotactic biopsy with an automated needle and gun can be an acceptable alternative to surgical biopsy in women with mammographically suspicious breast lesions.

Stereotactic breast biopsy with a biopsy gun.

One hundred three patients underwent stereotactic breast biopsy with an 18-, 16-, or 14-gauge cutting needle and a biopsy gun. After biopsy, a localization wire was placed and surgical biopsy performed. There was agreement of the histologic results in 89 cases (87%) including 14 of 16 cancers (87%) (kappa = 0.806). The gun biopsy yielded the correct diagnosis in four cases involving a lesion (including one cancer) that was missed at the surgical biopsy. Nine cases in which the lesion was missed at gun biopsy can be related to insufficient needle size, the greater difficulty in using one of the two stereotactic devices, and early inexperience with the technique. A 14-gauge needle was used in the last 29 biopsies, the results of which agreed with the surgical pathologic findings in 28 cases (97%). With greater experience, stereotactic-guided large-gauge automated percutaneous biopsy may prove to be an acceptable alternative to surgical biopsy in women with breast masses suspected at mammography.