Regulation of chloride channels by protein kinase C in normal and cystic fibrosis airway epithelia

Apical membrane chloride channels control chloride secretion by airway epithelial cells. Defective regulation of these channels is a prominent characteristic of cystic fibrosis. In normal intact cells, activation of protein kinase C (PKC) by phorbol ester either stimulated or inhibited chloride secretion, depending on the physiological status of the cell. In cell-free membrane patches, PKC also had a dual effect: at a high calcium concentration, PKC inactivated chloride channels; at a low calcium concentration, PKC activated chloride channels. In cystic fibrosis cells, PKC-dependent channel inactivation was normal, but activation was defective. Thus it appears that PKC phosphorylates and regulates two different sites on the channel or on an associated membrane protein, one of which is defective in cystic fibrosis.     

Comparison of the forage and grain composition from insect-protected and glyphosate-tolerant MON 88017 corn to conventional corn (Zea mays L.)

The next generation of biotechnology-derived products with the combined benefit of herbicide tolerance and insect protection (MON 88017) was developed to withstand feeding damage caused by the coleopteran pest corn rootworm and over-the-top applications of glyphosate, the active ingredient in Roundup herbicides. As a part of a larger safety and characterization assessment, MON 88017 was grown under field conditions at geographically diverse locations within the United States and Argentina during the 2002 and 2003-2004 field seasons, respectively, along with a near-isogenic control and other conventional corn hybrids for compositional assessment. Field trials were conducted using a randomized complete block design with three replication blocks at each site. Corn forage samples were harvested at the late dough/early dent stage, ground, and analyzed for the concentration of proximate constituents, fibers, and minerals. Samples of mature grain were harvested, ground, and analyzed for the concentration of proximate constituents, fiber, minerals, amino acids, fatty acids, vitamins, antinutrients, and secondary metabolites. The results showed that the forage and grain from MON 88017 are compositionally equivalent to forage and grain from control and conventional corn hybrids.     

Laryngeal paralysis: a study of 375 cases in a mixed-breed population of horses

Referred cases (n = 375) of laryngeal paralysis (1985-1998) from a mixed-breed equine population included 351 (94%) cases of recurrent laryngeal neuropathy (RLN) (idiopathic laryngeal hemiplegia) and 24 cases (6%) of laryngeal paralysis from causes other than RLN. Laryngeal movements were classified endoscopically into one of 6 grades, in contrast to the usual 4 grades. The RLN cases had a median grade 4 laryngeal paralysis, of which 96% were left-sided, 2% right-sided and 2% bilaterally affected. RLN cases included 204 (58%) Thoroughbred, 96 (27%) Thoroughbred-cross, 23 (7%) draught, 16 (5%) Warmbloods and 10 (3%) other breeds, including only 4 (1%) ponies. The median age of RLN cases at referral was 6 years (range 2-12) and their median height was 170.2 cm. The work of RLN horses included National Hunt racing (42%), flat racing (1%), hunting (19%), eventing (16%) and miscellaneous work (22%). Reported presenting signs in RLN-affected horses included abnormal exercise-related respiratory sounds in 90% and reduced exercise tolerance in only 64%. However, many horses were referred before their exercise tolerance could be fully assessed. Forty percent of the RLN cases had intercurrent disorders, including 10% with additional upper respiratory and 7% with lower respiratory tract diseases. The 24 nonidiopathic RLN cases included 12 with bilateral laryngeal paralysis, 11 (92%) of which were ponies. Bilateral laryngeal paralysis occurred with hepatic encephalopathy in 7 cases and following general anaesthesia in 2 cases. The 12 cases of acquired unilateral laryngeal paralysis included 7 caused by guttural pouch mycosis.     

Digestibility of cotton plant by-product diets for sheep at two levels of intake

Crossbred wethers (n = 48) were assigned randomly to 1 of 12 experimental diets, arranged in a 3 X 2 X 2 split plot to evaluate three levels of cotton plant by-product (25, 50 and 75% CPB), two levels of NaOH treatment of CPB (0 and 4%) and two levels of monensin supplementation (0 and 30 ppm, DM basis) at two intake levels (70 and 90% of ad libitum). Intake was a within-lamb variable. Ad libitum intake was established over an initial 17-d adjustment period. Feed intake and fecal output were recorded during collection periods with aliquots retained for laboratory analysis. Intake was affected by a linear CPB X monensin interaction (P less than .06) with monensin depressing intake more at higher CPB levels. Neutral detergent fiber (NDF) digestibility decreased linearly (P less than .001) as the dietary level of CPB increased. NaOH treatment of CPB improved (P less than .001) the digestibility of organic matter (OM) and NDF. The supplementation of 30 ppm monensin resulted in greater (P less than .004) apparent digestibilities of NDF and hemicellulose (HC). Increasing daily feed intake from 70 to 90% of ad libitum decreased (P less than .004) digestibility of NDF, HC and ADF.     

The Location Behavior of the Multinational Enterprise: Some Analytical Issues

ABSTRACT In the international business literature location behavior has traditionally been analyzed using Dunning's (1977 ) OLI framework, which focuses on the nature, role, and behavior of multinational enterprise (MNE). In this paper it is argued that this approach is now no longer appropriate for discussing the spatial behavior of MNEs, because of the fundamental changes which have taken place either in MNE organization or in the global and institutional environment for foreign direct investment (FDI). At the same time, the paper argues that current location theory from regional economics and economic geography is also largely unsuitable for discussing these issues, such that the spatial behavior of the MNE provides a set of difficult challenges to location analysts. There appears to have been some response to these issues from the international business and management literature, most notably the Porter literature on clusters. However, it is also argued here that this literature provides few, if any, real answers to the problems set by the geographical behavior of the MNE. It is concluded that a fusion of traditional economic geography approaches with a focus on the information and organizational aspects of the firm and the region under consideration may be a way forward for both theory and empirical analysis.     

Modeling trophic pathways, nutrient cycling, and dynamic stability in soils

Soil communities are compartmentalized into pathways of trophic interactions and nutrient flows that originate from plant roots, bacteria and fungi. The pathways differ in terms of the organisms that comprise them, the habitats that the organisms occupy and the rates by which the organisms process and transfer material and energy. The fungi, nematodes and arthropods within the fungal pathway live in air-filled pore spaces and water films, while the bacteria, protozoa, and nematodes within the bacterial pathway occupy water-filled pore spaces and water films. Organisms within the fungal pathway have longer generation times and process matter at slower rates than those within the bacterial pathway. Empirical studies have shown that under natural conditions the pathways co-exist in a stable manner. The relative sizes (indexed by the densities of organisms) and activities (indexed by nutrient-flow rates, excretion rates and respiration rates) of the pathways may change seasonally and in response to minor disturbances, but they persist. However, large anthropogenic and natural disturbances induce shifts in the relative sizes and activities of the pathways. Coincident with these shifts are reports of changes in the aboveground plant community and the availability and retention of plant limiting nutrients. We developed simple models of the bacterial and fungal pathways to explore the consequences of the observed shifts on the dynamic stability of the system. The more stable configurations occurred when there was a balance in the flow of nutrients between the two pathways. Large shifts in nutrient cycling and community structure towards either the fungal pathway or toward the bacterial pathway resulted in less stable or unstable configurations.     

Induction of mating behavior in rats by luteinizing hormone-releasing factor

Ovariectomized female rats treated with estrogen, in dosages too low to provoke mating, displayed this behavior when given subcutaneous injections of synthetic luteinizing hormone-releasing factor (LRF) 48 hours later. Two hours after the injection of LRF, components of female sexual behavior appeared. The lordosis reflex followed mounting by the male, and darting and hopping behavior was quite prevalent. On the other hand, treatment with estrogen followed by luteinizing hormone, follicle-stimulating hormone, or thyrotropin-releasing factor did not induce copulatory behavior. The results suggest that LRF may play a role in induction of mating behavior.     

Polyamine metabolism: a potential therapeutic target in trypanosomes

alpha-Difluoromethylornithine (RMI 71,782), a specific irreversible inhibitor of the first step in polyamine biosynthesis, that is, the formation of putrescine from ornithine by ornithine decarboxylase, cures mice infected with a virulent, rodent-passaged strain of Trypanosoma brucei brucei. This parasite is closely related to the trypanosomes that cause human sleeping sickness. The drug, which is remarkably nontoxic, was effective when administered in drinking water or by intubation. The ability of the compound to inhibit ornithine decarboxylase in vitro was demonstrated by the reduced amounts of putrescine synthesized from tritiated ornithine in Trypanosoma brucei suspensions. These observations direct attention to polyamine metabolism as a target for chemotherapy of parasitic diseases.     

Equine grazing preferences among winter annual grasses and clovers adapted to the southeastern united states

Forage acceptability of five cool season annual grasses and four annual clovers to yearling horses was evaluated in Georgia during winter and spring of two years. With cafeteria grazing trials, preference in consumption was determined by difference in forage harvested from mower strips before and after grazing. In four test grazing periods,annual ryegrass was preferred (P<.05) by the yearlings, averaging 75% apparent consumption of the dry forage. Oats and wheat were second in preference, averaging 47 and 41% respectively. Rye and triticale were least preferred, averaging only 35 and 32% apparent consumption, respectively. Of the annual clovers tested, crimson, berseem, and subterranean were all highly palatable (P<.05) to horses with an average consumption of 71% across all three clover varieties. Arrowleaf clover was unacceptable (P<.05), having only 22% apparent consumption. Yearling horses avoided grazing rye, triticale, and arrowleaf clover when other forages were available.