Cm Of Nodules Research Articles

The results of ultrasound-guided fine-needle aspiration biopsy for evaluation of nodular thyroid disease

Background. The purpose of this study was to determine whether ultrasonography (US) improves the accuracy and reduces the rate of nondiagnostic fine-needle aspiration biopsy (FNAB) of thyroid nodules. Methods. A review of 536 consecutive patients evaluated for nodular thyroid disease from 1990 to 2001 was completed to determine the results for US vs palpation-guided FNAB. Results. FNAB was used to evaluate 458 patients. US-guided FNAB was performed in 66 (12%) patients: 48 with a nonpalpable nodule, 14 with nondiagnostic standard FNAB, and 4 with a palpable nodule. US-guided FNAB was nondiagnostic in 15 (23%) patients. There were no false-positive or false-negative results. Standard FNAB was performed in 407 patients, 57 (14%) of whom had a nondiagnostic result. There were 2 (3%) false-positive and 3 (1.6%) false-negative results. In 14 patients with a nondiagnostic standard FNAB, US-guided FNAB yielded an adequate specimen in 7 (50%). Nodules evaluated by standard FNAB were 4.1 ± 0.1 cm (mean ± SEM) in size compared with 2.5 ± 0.1 cm for nodules evaluated by US-guided FNAB (P <.05). Conclusions. US improves the diagnostic yield in selected patients with nondiagnostic standard FNAB. The higher frequency of nondiagnostic US-guided FNAB was related to its selective use in patients with smaller nodules. Surgery 2002;132:648-54.

H2 oxidation, O2 uptake and CO2 fixation in hydrogen treated soils

In many legume nodules, the H2 produced as a byproduct of N2 fixation diffuses out of the nodule and is consumed by the soil. To study the fate of this H2 in soil, a H2 treatment system was developed that provided a 300 cm3 sample of a soil:silica sand (2:1) mixture with a H2 exposure rate (147 nmol H2 cm−3hr−1) similar to that calculated exist in soils located within 1–4 cm of nodules (30–254 nmol H2 cm−3hr−1). After 3 weeks of H2 pretreatment, the treated soils had a Km and Vmax for H2 uptake (1028 ppm and 836 nmol cm−3 hr−1, respectively) much greater than that of control, air-treated soil (40.2 ppm and 4.35 nmol cm−3 hr−1, respectively). In the H2 treated soils, O2, CO2 and H2 exchange rates were measured simultaneously in the presence of various pH2. With increasing pH2, a 5-fold increase was observed in O2 uptake, and CO2 evolution declined such that net CO2 fixation was observed in treatments of 680 ppm H2 or more. At the H2 exposure rate used to pretreat the soil, 60% of the electrons from H2 were passed to O2, and 40% were used to support CO2 fixation. The effect of H2 on the energy and C metabolism of soil may account for the well-known effect of legumes in promoting soil C deposition.