Tadpole begging reveals high quality.

Parents can benefit from allocating limited resources nonrandomly among offspring, and offspring solicitation (i.e. begging) is often hypothesized to evolve because it contains information valuable to choosy parents. We tested the predictions of three 'honest begging' hypotheses - Signal of Need, Signal of Quality and Signal of Hunger - in the tadpoles of a terrestrial frog (Oophaga pumilio). In this frog, mothers provision tadpoles with trophic eggs, and when mothers visit, tadpoles perform a putative begging signal by stiffening their bodies and vibrating rapidly. We assessed the information content of intense tadpole begging with an experimental manipulation of tadpole condition (need/quality) and food deprivation (hunger). This experiment revealed patterns consistent with the Signal of Quality hypothesis and directly counter to predictions of Signal of Need and Signal of Hunger. Begging effort and performance were higher in more developed and higher condition tadpoles and declined with food deprivation. Free-living mothers were unlikely to feed tadpoles of a nonbegging species experimentally cross-fostered with their own, and allocated larger meals to more developed tadpoles and those that vibrated at higher speed. Mother O. pumilio favour their high-quality young, and because their concurrent offspring are reared in separate nurseries, must do so by making active allocation decisions. Our results suggest that these maternal choices are based at least in part on offspring signals, indicating that offspring solicitation can evolve to signal high quality.

Are stereotaxic breast biopsies adequate?

BACKGROUND: Stereotaxic core breast biopsy (SCBB) has been proposed as a cost-effective and reliable method of evaluating mammographic lesions. This study evaluates an initial experience with SCBB and assesses the adequacy of the biopsy specimens obtained. METHODS: Two hundred forty-one SCBB were performed on 221 patients during 13 months by four radiologists. Mammograms were assigned a suspicion index on a scale of 1 to 5. One pathologist performed a blinded retrospective review of all SCBB specimens and assigned an adequacy score based on the quality and amount of the tissue present. RESULTS: The majority of SCBB were ordered by general surgeons (67%). A suspicion index score of 3 was assigned to 74% of lesion specimens. Twelve percent of specimens were malignant. Overall SCBB adequacy (score > or = 2) was 77%. Adequacy was present in 74% of benign biopsy specimens as compared with 100% of malignant specimens (p < 0.005). Only 62% of specimens reported as benign without specific features were adequate. There were no differences in adequacy between individual radiologists or during the study period. CONCLUSIONS: SCBB is largely used by surgeons to assess indeterminate mammographic lesions. One of four benign specimens was inadequate. Benign SCBB specimens must be interpreted with caution.

Ethanol thrombotherapy of esophageal varices: further experience.

Fifty patients with liver cirrhosis (13 Child class B, 37 class C) were treated for variceal hemorrhage during a 3-year period using the transhepatic selective catheterization and injection of absolute ethanol. Technical failure of the procedure was encountered in 13 instances. The causes were the presence of massive ascites and rigidly contracted liver, cavernous transformation of the main portal vein, and severe coagulopathy. Of the 13 failures, 12 were in Child class C and one in class B. Of 37 initially successfully treated patients, 13 rebled subsequently. Nine of these were Child class C and four were class B. Rebleeding was fatal in five of nine class C patients. Rebleeding was due to recanalization of previously thrombosed access channel in two of 13 patients. Nine patients died, despite successful thrombosis of varices, due to underlying medical conditions. Fifteen patients survived 6 months or more after initial thrombosis without rebleeding. Child class B patients are better candidates for this treatment technique because more favorable treatment results are expected in them. Child class C patients with massive ascites and severely contracted and rigid liver pose a significant technical challenge, but in about one-third, successful control of variceal bleeding can be achieved. Most of those who survived more than 6 months showed varying degrees of improvement in clinical signs and symptoms.