Stable isotope records of sei whale baleens from Chilean Patagonia as archives for feeding and migration behavior

Carbon (δ13C) and nitrogen (δ15N) stable isotope variations in baleen plates of sei whales (Balaenoptera borealis) stranded after a mass mortality event in Chilean Patagonia were investigated to assess potential dietary and migratory patterns. Carbon and nitrogen isotope ratios of seven baleens from six individuals were analyzed. The δ13C values ranged from - 19.1 to - 15.9‰ and the δ15N values from 8.7 to 15.4‰. Variations of up to 2.9‰ for δ13C and 5.3‰ for δ15N were observed within one baleen. Carbon and nitrogen isotope records of each baleen were significantly correlated and showed recurring oscillations confirmed by wavelet analyses. Oscillations slightly differed in periodicity indicating variable baleen growth rates between 10.0 and 16.5 cm/year. Food sources of the whales are discussed in terms of available isotope data for potential prey taxa and potential migratory behavior on the basis of latitudinal isotope gradients of particulate organic matter. Cyclicity could be explained by regular migrations of the sei whales from subtropical calving areas to high-latitude foraging grounds. δ15N records of baleens differed between individuals eventually pointing to diverse feeding and migratory preferences among sei whale individuals.

Spatial location memory in amnesia: binding item and location information under incidental and intentional encoding conditions

Items located within an array were presented to alcoholic Korsakoff and nonalcoholic mixed-etiology amnesics and to alcoholic and normal controls. Recognition memory for the locations of items was tested after incidental and intentional encoding. When equated on item recognition, neither Korsakoff amnesics nor alcoholic controls benefited from intentional, relative to incidental, encoding instructions. Furthermore, Korsakoff amnesics showed neither disproportionately impaired incidental nor intentional location recognition memory relative to alcoholic controls. In contrast, mixed-etiology amnesics profited significantly from intentional location acquisition relative to incidental instructions, and were impaired somewhat in incidental, but not intentional, location memory relative to normal controls. We discuss these data in relation to Mayes' (1992) contextual memory deficit hypothesis and Hirst's (1982) automatic encoding deficit account, and propose an alternative framework in which the location memory deficit observed in mixed-etiology amnesics is interpreted as a disruption to the ability to bind item and location information.

Knowledge of New English vocabulary in amnesia: an examination of premorbidly acquired semantic memory

To assess if amnesics have intact remote memory for general semantic information, we examined memory for vocabulary words with known dates of entry into the language between 1955 and 1989. Amnesics of mixed etiology with acute onset performed normally on both a recall and a recognition task. Korsakoff patients, in contrast, were impaired on both tasks and demonstrated a gradient such that their knowledge of words acquired during more recent time periods was worse than that of words acquired during more remote time periods. The improvement in performance associated with recognition testing was larger for Korsakoff patients than for control subjects and correlated significantly with a composite measure of frontal dysfunction. These findings suggest a deficit in the controlled search and retrieval of semantic information in Korsakoff patients. The implications of the differential performance of Korsakoff and mixed etiology amnesics for explanations of temporally graded retrograde amnesia are discussed.

Identification of the keratan sulfate attachment sites on bovine fibromodulin

The small keratan sulfate-substituted proteoglycan (fibromodulin) from articular cartilage was shown to contain keratan sulfate linked to the core protein through N-glycosidic linkages to residues Asn-109, Asn-147, Asn-182, and Asn-272. Biosynthetic experiments with articular chondrocytes in the presence of tunicamycin, an inhibitor of N-linked oligosaccharide synthesis, demonstrated a specific inhibition of [35S]SO4 incorporation into fibromodulin. Under the same conditions no effect on the addition of keratan sulfate to the large aggregating proteoglycan was detected. Fibromodulin substituted with keratan sulfate was purified from bovine articular cartilage extracts by density gradient centrifugation, ion-exchange chromatography, and gel-permeation chromatography. Isolation of glycosylated peptides from tryptic digests of fibromodulin by ion-exchange chromatography and reversed-phase high performance liquid chromatography revealed four separate hexosamine-rich species, that were also immunoreactive with monoclonal antibody 5D4. Sequence analysis of these glycopeptides gave blank cycles at positions which corresponded to Asn followed by X-Ser/Thr in the sequence derived from cDNA (Oldberg, A., Antonsson, P., Lindblom, K., and Heinegard, D. (1989) EMBO J. 8, 2601-2604). Hence, all four Asn residues in the leucine-rich region of the fibromodulin core protein can serve as acceptor sites for keratan sulfate addition.

Insensitivity of the cold pressor stimulation test for the diagnosis of coronary artery disease

Cold pressor stimulation (CPS) was compared with supine bicycle exercise during radionuclide ventriculography as a procedure for diagnosing coronary artery disease (CAD). Thirty patients were studied. In the 18 patients with angiographically proved CAD, left ventricular ejection fraction (LVEF) decreased a mean of 5.0 +/- 1.0 ejection fraction units (+/- SEM) in response to CPS. Only two patients developed a new wall motion abnormality. In response to maximal supine exercise, the CAD group showed a mean decrease in LVEF from rest of 1.9 +/- 1.1%. Nine patients developed an exercise-induced wall motion abnormality. In the 12 patients with angiographically proved normal coronary arteries, LVEF decreased a mean of 5.8 +/- 1.3 units in response to CPS and increased a mean of 9.2 +/- 1.2% in response to exercise. Thus, the LVEF response to CPS was not significantly different in the CAD and normal groups (5.0 +/- 1.0 vs 5.8 +/- 1.3, NS). These same patients demonstrated the expected difference in LVEF response to exercise. We conclude that CPS produces similar changes in LVEF in patients with and without CAD, and therefore is not useful in diagnosing ischemic heart disease.