DETERMINATION OF GUSTATORY SUCROSE THRESHOLD IN WATER BY USE OF A LINEAR SUCROSE GRADIENT

A novel experimental method was developed which allows the determination of the threshold concentration of sucrose by use of a linear sucrose gradient in water. With this method a continuous tasting of the test-liquid is possible. A panel of 15 persons experienced in taste-testing was used. Three gradients of different steepness were applied: 0 to 1.5% (w/w) sucrose in 2 min (I), 3 min (II) and 4 min (III). The results of the new method were compared with those of the standard method (DIN). With gradients I and II we found values which were significantly higher than those of the standard method (I: 0.49% (w/w); II: 0.46% (w/w); DIN: 0.31% (w/w)), whereas with gradient III the same threshold value was found as with the DIN-Method (III: 0.32% (w/w)).     

Bone marrow-derived mononuclear phagocytes autoregulate mannose receptor expression

This study extends our previous observation that surface mannose receptor expression by pure populations of CSF-1-dependent bone marrow-derived macrophages increases with time (Clohisy, D. R., Bar-Shavit, Z., Chappel, J. C., and Teitelbaum, S. L. (1987) J. Biol. Chem. 262, 15922-15929). We presently find, however, that the progressive enhancement of 125I-mannose-bovine serum albumin (125I-Man-BSA) binding per cell reflects cell number rather than duration of culture. In fact, macrophages plated at high density bind 8-fold more 125I-Man-BSA than do their low density counterparts, with no difference in receptor-ligand affinity. Furthermore, cells cultured at high density are ultimately subjected to lower levels of exogenously provided macrophage growth factor, and fewer are in interphase. By obtaining synchronous populations of quiescent bone marrow macrophages, however, we demonstrate that neither cell cycling nor attendant levels of colony stimulating factor-1 influence mannose receptor expression. Our next series of experiments established that density-related mannose receptor expression reflects removal, by marrow macrophages, of a "down-regulating" factor contained in culture medium. To this end, we treated mononuclear phagocytes with either macrophage- or control-conditioned medium and found that, via a fetal calf serum-residing protein(s), only control medium is capable of noncompetitively reducing 125I-Man-BSA binding in a dose-dependent manner. Moreover, reconstituted 20-40% (NH4)2SO4-precipitable fractions derived from either sham-conditioned medium or fetal calf serum are capable of down-regulating mannose receptor expression. Alternatively, the same fraction obtained from macrophage-conditioned medium contains no such activity. Finally, initial characterization of the down-regulating factor reveals it to be acid-activable and trypsin-sensitive, yet resistant to heating to at least 80 degrees C, ribonuclease A, or freezing and thawing. We conclude that bone marrow macrophages up-regulate expression of their own plasma membrane mannose receptor by inactivating a noncompetitive, serum-residing inhibitory protein(s).     

Effect of neurotensin on pancreatic function in man

The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs.     

Delimitation of the maritime boundary in the gulf of Maine area

The compulsory dispute settlement regime included in the 1982 Law of the Sea Convention is recognized as one of the most comprehensive in a modern international convention. Yet, in the recent application of this regime, the question has arisen as to whether the procedural prerequisites associated with the LOS Convention's compulsory dispute settlement mechanism are so arduous as to avoid binding and compulsory jurisdiction in most instances. This article addresses that question by examining, in particular, the reasoning of the Southern Bluefin Tuna arbitration tribunal, which found Article 281 of Section 1 of the LOS Convention to bar jurisdiction to the compulsory dispute settlement mechanism prescribed by the Convention, and offers suggestions as to how states might distinguish or overcome the barriers imposed by the Southern Bluefin Tuna tribunal in future cases.     

Bone cancer pain and the role of RANKL/OPG

Cancer-induced bone diseases are common and can have a devastating impact at the end of life. One of the most difficult sequelae of cancer is metastases to the skeleton, an event that results in bone destruction and bone cancer pain. Bone cancer pain is usually progressive as the disease advances, and is particularly difficult to treat. Recently, experimental models of bone cancer pain have been developed and have provided seminal insight in understanding the pathophysiology of bone cancer pain. Animal models of bone cancer provided the finding that bone destruction (osteolysis) is associated with pain, and it has been determined that cancer-induced osteolysis is mediated by osteoclasts. Having established that RANK ligand contributed to cancer-induced osteoclastogenesis, it was determined that disruption of the RANKL-RANK axis with OPG inhibited tumor-induced osteoclastogenesis and decreased bone cancer pain.     

A spatial analytical approach for selecting reintroduction sites for burbot in English rivers

1. Availability of suitable habitat is a prerequisite for species reintroduction success, and to ensure population persistence, investigations of a species’ habitat utilisation throughout its life history should be conducted as part of a feasibility study. 2. Habitat utilisation models for burbot, Lota lota, developed using data from field studies conducted in France and Germany and information from the literature were used to assess the feasibility of reintroducing burbot into rivers of its former native range in eastern England. 3. Per cent tree roots, aquatic vegetation and flow types were important predictors of adult burbot abundance. Furthermore, the habitat utilisation models were supplemented with information from the literature, which suggested that off‐channel habitat such as wetlands and backwaters is important for spawning and nursery stages. 4. An assessment of the habitat availability in the rivers of the burbot’s former native range using variables related to spawning and nursery and adult life stages showed that although adult habitat was widely distributed, the availability of spawning and nursery habitat was less abundant, potentially limiting successful reestablishment. 5. Potential suitable habitat was concentrated in the central and southern areas of the species’ former English distribution. Overall, rivers of the burbot’s former range potentially afford suitable habitat to sustain a reintroduced population. However, sites should be preferentially selected on the basis of having appropriate spawning and nursery areas.