Basal and cold-induced fatty acid uptake of human brown adipose tissue is impaired in obesity.

Fatty acids (FA) are important substrates for brown adipose tissue (BAT) metabolism, however, it remains unclear whether there exists a difference in FA metabolism of BAT between lean and obese healthy humans. In this study we evaluated supraclavicular BAT fatty acid uptake (FAU) along with blood perfusion in lean and obese subjects during cold exposure and at room temperature using positron emission tomography (PET)/computed tomography (CT). Additionally, tissue samples were taken from supraclavicular region (typical BAT region) from a subset of subjects to evaluate histological presence of BAT. Non-shivering cold stress elevated FAU and perfusion of BAT in lean, but not in obese subjects. Lean subjects had greater FAU in BAT compared to obese subjects during cold exposure and interestingly also at room temperature. The higher BAT FAU was related to younger age and several indicators of superior systemic metabolic health. The subjects who manifested BAT histologically had several folds higher BAT FAU compared to subjects with no such histological manifestation. Together, obese subjects have less active tissue in supraclavicular region both in basal and cold-activated state and the FA metabolism of BAT is blunted in obesity.

Efficacy of fine-needle capillary biopsy in the assessment of patients with superficial lymphadenopathy.

BACKGROUND: Fine-needle aspiration biopsy (FNAB) is an important tool for the cytologic assessment of patients with lymphadenopathy. The nonaspiration method (without the use of a syringe or a handle), or fine-needle capillary biopsy (FNCB), is becoming popular for its ease of learning and use. The authors compared the two techniques of fine-needle biopsy (with and without aspiration) for identifying the cause of superficial lymphadenopathy. METHODS: Over a 2-year period 50 cytologic examinations were conducted in patients with superficial lymphadenopathy. Both procedures were performed at the same site; the order in which they were performed was determined randomly. Slides were fixed in a similar manner and examined by a cytotechnologist and pathologists blind to the procedure. Scores were tabulated and compared and diagnosis was confirmed by histologic examination. RESULTS: The best and the average score for the yield of cellular material was higher with FNCB (P < 0.004). Cell preservation also was superior with FNCB (P = 0.00066). However, the failure rate was lower with FNAB (P = 0.7662). CONCLUSIONS: FNCB of superficial lymph nodes yields adequate cellular material of superior quality, which may be advantageous in certain situations. However, the diagnostic yield does not appear to be significantly increased using this technique.