Faculty Bibliography

Approximately 2,000 patients a year are diagnosed with oral cancer in New York State. In an effort to control this deadly disease, Governor George Pataki has taken a leadership role in the United States by mandating and funding training for dentists in the prevention and early detection of oral cancer. The purpose of this article is to highlight the epidemiology of oral cancer, to show how the dental profession can contribute to the health of the citizens of New York State, and to provide practical guidelines for both tobacco cessation intervention and utilization of existing technology for the early detection of oral cancer and precancerous conditions in the general dental practice setting

This study compares two potential magnetic resonance imaging (MRI) indices for noninvasive early detection of tumor response to chemotherapy: the spin-lattice relaxation in the rotating frame (T1rho) and the transverse relaxation time (T2). Measurements of these relaxation parameters were performed on a s.c. murine radiation-induced fibrosarcoma (RIF-1) model before and after cyclophosphamide treatment. The number of pixels exhibiting T1rho values longer than controls in viable regions of the tumor increased significantly as early as 18 h after drug administration and remained elevated up to 36 h after treatment (P < 0.005). Although a trend of increasing T2s relative to controls was noted in viable regions of the tumor 36 h after treatment, the changes were not statistically significant. Histological examination indicated a decrease in mitotic index that paralleled the changes in T1rho. We conclude that T1rho measurements may be useful for noninvasive monitoring of early response of tumors to chemotherapy.

Magnetic relaxation has been used extensively to study and characterize biological tissues. In particular, spin-lattice relaxation in the rotating frame (T(1rho)) of water in protein solutions has been demonstrated to be sensitive to macromolecular weight and composition. However, the nature of the contribution from low frequency processes to water relaxation remains unclear. We have examined this problem by studying the water T(1rho) dispersion in peptide solutions ((14)N- and (15)N-labeled), glycosaminoglycan solutions, and samples of bovine articular cartilage before and after proteoglycan degradation. We find in model systems and tissue that hydrogen exchange from NH and OH groups to water dominates the low frequency water T(1rho) dispersion, in the context of the model used to interpret the relaxation data. Further, low frequency dispersion changes are correlated with loss of proteoglycan from the extra-cellular matrix of articular cartilage. This finding has significance for the noninvasive detection of matrix degradation.

A fast spin-echo sequence weighted with a time constant that defines the magnetic relaxation of spins under the influence of a radio-frequency field (T1(rho)) was used in six subjects to measure magnetic resonance (MR) relaxation times in the knee joint with a 1.5-T MR imager. A quantitative comparison of T2- and T1(rho)-weighted MR images was also performed. Substantial T1(rho) dispersion was demonstrated in human articular cartilage, but muscle did not demonstrate much dispersion. T1(rho)-weighted images depicted a chondral lesion with 25% better signal-difference-to-noise ratios than comparable T2-weighted images. This technique may depict cartilage and muscular abnormalities.

RATIONALE AND OBJECTIVES/OBJECTIVE:The goal of this study was to evaluate the utility of T1rho weighting in magnetic resonance imaging of murine brain tumors. MATERIALS AND METHODS/METHODS:S91 Cloudman melanoma was implanted in mouse brains (n = 4). A T2-weighted spin-echo (SE) and a T1rho-weighted fast SE-based sequence were performed on a 4-T clinical imager. T2 and T1rho maps were computed. The tumor-to-normal-tissue contrast was compared between T2-weighted, T1rho-weighted, proton-density-weighted, and pre- and postcontrast T1-weighted SE images. RESULTS:The tumor-tissue contrast of the T1rho-weighted images was similar to that of the T2-weighted images but less than that of the postcontrast T1-weighted images. The T1rho-weighted images provided better definition of tumor boundaries than T2-weighted images. At spin-locking powers of 0.5 and 1.5 kHz, the T1rho of the tumor was 64.0 msec +/- 0.46 and 68.65 msec +/- 0.59, respectively. There was no significant inter- or intra-animal variation in T1rho for tumor or normal brain cortex. CONCLUSION/CONCLUSIONS:T1rho-weighted imaging performed at low spin-lock strengths qualitatively depicted tumor borders better than proton-density or T2-weighted imaging and could be useful in treatment planning when combined with other imaging sequences.

BACKGROUND: Multiparity and the use of oral contraceptives reduce the risk of ovarian cancer, but their effects on this risk in women with a BRCA1 or BRCA2 mutation are unclear. METHODS: We conducted a population-based case-control study of ovarian cancer among Jewish women in Israel. Women were tested for the two founder mutations in BRCA1 and the one founder mutation in BRCA2 that are known to be common among Jews. We estimated the effects of parity and oral-contraceptive use on the risk of ovarian cancer in carriers and noncarriers in separate analyses that included all control women, who did not have ovarian cancer. RESULTS: Of 751 controls who underwent mutation analysis, 13 (1.7 percent) had a BRCA1 or BRCA2 mutation, whereas 244 of 840 women with ovarian cancer (29.0 percent) had a BRCA1 or BRCA2 mutation. Overall, each additional birth and each additional year of use of oral contraceptives were found to lower the risk of ovarian cancer, as expected. Additional births were protective in separate analyses of carriers and noncarriers, but oral-contraceptive use appeared to reduce the risk only in noncarriers; among carriers, the reduction in the odds of ovarian cancer was 12 percent per birth (95 percent confidence interval, 2.3 to 21 percent) and 0.2 percent per year of oral-contraceptive use (-4.9 to 5.0 percent). CONCLUSIONS: The risk of ovarian cancer among carriers of a BRCA1 or BRCA2 mutation decreases with each birth but not with increased duration of use of oral contraceptives. These data suggest that it is premature to use oral contraceptives for the chemoprevention of ovarian cancer in carriers of such mutations.

OBJECTIVE: To describe and evaluate an ear piercing and earring retention method for individuals with metal hypersensitivity. SETTING: Private facial plastic surgery practice associated with a tertiary care medical center. METHODS: Thirty-one patients with a history of hypersensitivity to metallic jewelry (62 ears) underwent earlobe piercing with an intravenous catheter. RESULTS: None of the patients experienced an infection or hypersensitivity reaction. All patients were able to wear nickel-free earrings for short periods without using the shortened catheter. CONCLUSION: Using the distal shaft of an intravenous catheter as an earring post sheath is a safe and effective technique that allows hypersensitive individuals to wear earrings in pierced ears on a limited basis.

Cisplatin (cis-diamminedichloroplatinum(II) (CDDP)) is a widely used, highly effective, oncolytic agent that has serious ototoxic side-effects. To test the effectiveness of local delivery, of L-methionine (L-Met) as an otoprotective agent against CDDP ototoxicity, we used a rat model of a highly metastatic breast cancer tumor, i.e. Fisher 344 rats implanted with MTLn3 breast cancer cells. Four experimental groups were evaluated--I: untreated; II: CDDP-treated (three dosages); III: systemically-delivered L-Met + CDDP-treated; IV: locally delivered L-Met + CDDP-treated. The integrity of the outer hair cells (OHCs) was determined using scanning electron microscopy (SEM); hearing was assessed by recording auditory brainstem responses (ABRs) at multiple frequencies. The chemotherapeutic effectiveness of CDDP was quantified by measuring changes in tumor mass and the presence of tumor metastasis. L-Met provided otoprotection of the OHCs against CDDP toxicity in the cochleae of rats following either systemic (III) or local (IV) administration. The ABRs were unchanged in each of the L-Met protection Groups (III and IV) and in the untreated animals of Group I. Treatment with CDDP only (II) induced significant hearing losses at both 16 and 18 kHz when compared to ABRs of untreated rats(I). CDDP was effective in controlling the MTLn3 initiated breast cancer tumors in the CDDP-treated (II) and the local L-Met protection, CDDP-treated (IV) Groups. In contrast, the tumors in the systemic L-Met protection, CDDP-treated Group (III) were not controlled by the CDDP treatment regime. This study demonstrates that local delivery of L-Met to the scala tympani of the cochlea via the round window membrane (IV) provides effective protection against CDDP ototoxicity without compromising its ability to control a highly metastatic form of cancer.