The addition of CO2 to traditional taste solutions alters taste quality

Previous studies of the effect of carbonation on taste perception have suggested that it may be negligible, manifesting primarily in increases in the perceived intensity of weak salt and sour stimuli. Assuming CO2 solutions in the mouth stimulate only trigeminal nerve endings, this result is not altogether surprising; however, there are neurophysiological data indicating that CO2 stimulates gustatory as well as trigeminal fibers. In that case, carbonation might alter the quality profile of a stimulus without producing substantial changes in overall taste intensity--much as occurs when qualitatively different taste stimuli are mixed. To address this possibility, subjects were asked to rate the total taste intensity of moderate concentrations of stimuli representing each of the basic tastes and their binary combinations, with an without added carbonation. They then subdivided total taste intensity into the proportions of sweetness, saltiness, sourness, bitterness and 'other taste qualities' they perceived. The addition of carbonation produced only small increases in ratings of total taste intensity. However, rather dramatic alterations in the quality profiles of stimuli were observed, particularly for sweet and salty tastes. The nature of the interaction is consistent with a direct effect of carbonation/CO2 on the gustatory system, although the possibility that at least some of the observed effects reflect trigeminal-gustatory interactions cannot be ruled out.      

Binding of unmodified low-density lipoproteins to human fibroblasts. An investigation by immunoelectron microscopy.

The bindinf of unmodified low density lipoproteins to the plasma membrane of fibroblasts was studied at the ultrastructural level. The bound low density lipoprotein was visualized by an indirect immunoperoxidase technique, with the use of an antiserum against apoprotein B. Immunoreactive regions representing bound apoprotein B were found on the plasma membrane, in indented regions with a diameter of 0.15--0.30 micrometer and a fuzzy coat on the cytoplasmic side. Fibroblasts from a patient homozygous for hyperlipoproteinaemia type IIa showed no immunoreactive material in the indented regions. The specific 125I-labelled low density lipoprotein binding to these homozygous fibroblasts was 7% compared to control fibroblasts.     

Immunoenzymehistochemical demonstration of the binding of low density lipoproteins to cultured human fibroblasts

Summary Using an indirect cytochemical immunoperoxidase technique, we were able to demonstrate the binding of low density lipoprotein to cultured human fibroblasts. With this technique, fibroblasts from a patient suffering from homozygous hyperlipoproteinaemia type IIa did not show this binding.The method described here allows study of the localization of unmodified low density lipoproteins binding to cultured fibroblasts.     

A comparison between vitamin K-dependent carboxylase from normal and warfarin-treated cows

Detergent-solubilized microsomal preparations that catalyse the vitamin K-dependent γ-carboxylation of glutamic acid residues in peptide and protein substrates, have been obtained from the livers of normal and warfarin-treated cows. The preparations from warfarin-treated animals contained more endogenous substrate than those from normal cows, but otherwise the two preparations were indistinguishable. The enzymes vitamin K reductase and γ-glutamyl carboxylase, may function independently of each other in this system. They are, nevertheless, intimately linked in some way, so that the reduced vitamin K that is produced by the former enzyme can be used immediately by the latter.     

Warfarin-induced accumulation of vitamin K-dependent proteins comparison between hepatic and non-hepatic tissues

At high concentrations (7.5 mg/kg body weight), coumarin derivatives inhibit the vitamin K-dependent carboxylation reaction in hepatic as well as in non-hepatic tissues. Therapeutically this anti-vitamin K drug is frequently used in 100-fold lower dosages. Under these conditons the production of the vitamin K-dependent clotting factors in the liver is only partially inhibited. Using the rat as an experimental animal, we could demonstrate, that during a dayly intake of these low amounts of warfarin, endogenous substrates for vitamin K-dependent carboxylase accumulate in the lung, spleen and testis in a similar way as they do in liver. Therefore it seems that in vivo the carboxylating enzyme systems in all these tissues are inhibited. It seems plausible, that this effect of warfarin is not restricted to rats, but that it will also occur in patients under anticoagulant therapy.     

The importance of plankton to Cassin's auklets during breeding

The breeding chronology, food habits, growth and reproductivesuccess of Cassin's Auklets, Ptychoramphus aleuticus, were investigatedon Triangle Island, British Columbia. The breeding of Cassin'sAuklets coincides with the plankton bloom in the eastern NorthPacific. Cassin's Auklets in British Columbia feed their youngmostly large copepods, Calanus cristatus, and euphausiids, chieflyThysanoessa spinifera, but fish was an important food item inone summer. Chicks which hatched early, grew and survived betterthan late-hatched chicks and this may relate to food availability.Adults and chicks on Triangle Island were heavier than thoseon South Farallon Island, California. The heavier weight andgreater numbers of Cassin's Auklets in British Columbia as comparedwith regions to the south may relate to Calanus cristatus availabilityand abundance in northern areas.