Cytochalasin inhibition of isolated rat gastric parietal cell function

Submicrogram concentrations (0.04-0.29 microM) of the microfilament disrupting agents cytochalasins D, E, and B (CD, CE, CB) were shown to inhibit secretagogue-stimulated 14C-aminopyrine accumulation (AP) in isolated rat gastric mucosal parietal cells. The microtubule disrupting agent colchicine had little influence on AP accumulation. Histamine- and dibutyryl cyclic AMP (DbcAMP)-stimulated AP accumulation was inhibited with an order of potency CD greater than CE approximately equal to CB. CB inhibition of these secretagogue actions was, however, only approximately 65-70% of the maximal stimulated response, whereas CD and CE caused 100% inhibition. On the other hand, carbamylcholine-stimulated AP accumulation was inhibited 100% by all cytochalasins tested with an order of potency CD approximately equal to CE greater than CB. These data are discussed in relation to acid secretagogue-induced morphological changes involving actin filament organization in parietal cells.     

Beyond pain in fibromyalgia: insights into the symptom of fatigue

Fatigue is a disabling, multifaceted symptom that is highly prevalent and stubbornly persistent. Although fatigue is a frequent complaint among patients with fibromyalgia, it has not received the same attention as pain. Reasons for this include lack of standardized nomenclature to communicate about fatigue, lack of evidence-based guidelines for fatigue assessment, and a deficiency in effective treatment strategies. Fatigue does not occur in isolation; rather, it is present concurrently in varying severity with other fibromyalgia symptoms such as chronic widespread pain, unrefreshing sleep, anxiety, depression, cognitive difficulties, and so on. Survey-based and preliminary mechanistic studies indicate that multiple symptoms feed into fatigue and it may be associated with a variety of physiological mechanisms. Therefore, fatigue assessment in clinical and research settings must consider this multi-dimensionality. While no clinical trial to date has specifically targeted fatigue, randomized controlled trials, systematic reviews, and meta-analyses indicate that treatment modalities studied in the context of other fibromyalgia symptoms could also improve fatigue. The Outcome Measures in Rheumatology (OMERACT) Fibromyalgia Working Group and the Patient Reported Outcomes Measurement Information System (PROMIS) have been instrumental in propelling the study of fatigue in fibromyalgia to the forefront. The ongoing efforts by PROMIS to develop a brief fibromyalgia-specific fatigue measure for use in clinical and research settings will help define fatigue, allow for better assessment, and advance our understanding of fatigue.     

Stable expression of human D3 dopamine receptors in GH4C1 pituitary cells.

Human D3 dopamine receptor DNA was stably transfected into GH4C1 pituitary cells. Displacement of iodosulpiride binding in hD3 transfected cells (Kd = 0.3 nM, Bmax = 89 fmol/mg protein) by dopaminergic ligands was indistinguishable from that of hD3 receptors in CHO cells. Only two clonal cell lines exhibited weak GppNHp-dependent shifts in [3H]N-0437 binding, and these were used for functional assays. Neither arachidonic acid metabolism, cAMP levels, inositol phosphate turnover, intracellular calcium, or potassium currents were consistently affected by dopamine (1-10 microM). The paucity of responses indicates that human D3 receptors do not couple efficiently to these second messengers in GH4C1 cells.     

How common are common fragile sites: variation of aphidicolin-induced chromosomal fragile sites in a population of the deer mouse (Peromyscus maniculatus)

Aphidicolin (APC)-induced chromosomal gaps and breaks were analyzed for ten deer mice (Peromyscus maniculatus) from a natural population. The FSM statistical methodology was used to identify fragile sites as chromosomal loci exhibiting significantly non-random numbers of gaps/breaks in each individual and enabled an assessment of variation in fragile sites among the individuals. The individual deer mice exhibited as few as 7 to as many as 19 of the populational total of 34 sites. Two sites were fragile in all individuals and 13 sites were fragile in single individuals only. Defined by populational frequencies of greater than 50%, high-frequency fragile sites constituted 26% of the populational total. Approximately 35% of the total fragile sites were fragile in 20–40% of the population (low-frequency fragile sites) and about 38% were fragile in single individuals only. Analysis of the data pooled over all individuals identified significantly non-random breakage at 80 sites, 47 of which were not identified as fragile in any single individual. It appears, therefore, that fragile site identifications from pooled data have fostered an inflated estimate of the numbers and frequencies of common fragile sites. Comparison of the fragile site and spontaneous breakage (control) data suggest that APC-induced fragile sites represent regions of chromosomes that experience elevated levels of somatic mutation. Additionally, the occurrence of APC-induced fragile sites at or near the interstitial breakpoints of two pericentric-inversion polymorphisms in this population supports the hypothesis that fragile sites experience an increased rate of meiotic chromosomal mutation and are predisposed to undergo phylogenetic rearrangement. Received: 22 January 1997 / Accepted: 24 February 1997     

A new species of Isospora (Apicomplexa: Eimeriidae) from Carolina chickadee (Passeriformes: Paridae), from Oklahoma,USA

Systematic Parasitology - The Carolina chickadee, Poecile carolinensis Audubon is a relatively small songbird belonging to the tit and chickadee family Paridae. Feces from three P. carolinensis...     

Identification of bisphosphatidic acid and its plasmalogen analogues in the phospholipids of a marine bacterium.

A relatively nonpolar unidentified phospholipid (phospholipid X) , isolated from the gram-negative marine bacterium MB 45, was characterized both chromatographically and by chemical analysis. Phospholipid X was shown to be an acidic phospholipid without vicinal hydroxyl, free-amino, or amide groups. The presence of O-alkenyl groups was indicated by a positive reaction for plasmalogen. Mild alkaline methanolysis of phospholipid X yielded only glycerophosphoryglycerol as the derivative. Acetolysis produced only diacyl-glycerol monoacetate. Clevage of O-alkenyl chains by methanolic hydrochloride resulted in the formation of three lyso derivatives. It was estimated that 18.2% of phospholipid X was plasmalogen. From these data, together with chromatographic comparisons with standards, infrared spectra, a molecular weight estimation, and the determination of the glycerol-phosphate-acyl ester ratio, it was concluded that phospholipid X was bisphosphatidic acid mixed with its plasmalogen analogues.     

Somatic embryo cycling: Evaluation of a novel transformation and assay system for seed-specific gene expression in soybean

Somatic embryo cycling, a modification of soybean somatic embryogenic suspension culture, was developed as an efficient and rapid method of producing tissue suitable for stable transformation of soybean germplasm by biolistic particle bombardment. Instead of using immature seed explants, cotyledon-staged somatic embryo hypocotyls were placed on auxin-containing medium, where they initiated new somatic embryos primarily from single epidermal cells. By bombarding hypocotyls prior to initiation of subsequent embryo formation, we have effectively transformed soybean somatic embryos with the reporter genes neomycin phosphotransferase,gb-glucuronidase, and a mammalian stearyl CoA delta-9 desaturase, controlled by a seed-specific promoter. These embryos contain significantly reduced levels of saturated palmitic and stearic fatty acids, and significant amounts of monounsaturated palmitoleic acid, which is not normally abundant in soybean seeds. This study demonstrates the effectiveness of somatic embryo cycling for soybean transformation, and for testing expression of genes for seed-specific proteins. Abnormal flower development in recovered plants is a limitation for application of the technique to produce transgenic seed at present.     

Long-Term Evolution of the Hypervariable Region of Hepatitis C Virus in a Common-Source-Infected Cohort

The long-term evolution of the hepatitis C virus hypervariable region (HVR) and flanking regions of the E1 and E2 envelope proteins have been studied in a cohort of women infected from a common source of anti-D immunoglobulin. Whereas virus sequences in the infectious source were relatively homogeneous, distinct HVR variants were observed in each anti-D recipient, indicating that this region can evolve in multiple directions from the same point. Where HVR variants with dissimilar sequences were present in a single individual, the frequency of synonymous substitution in the flanking regions suggested that the lineages diverged more than a decade previously. Even where a single major HVR variant was present in an infected individual, this lineage was usually several years old. Multiple lineages can therefore coexist during long periods of chronic infection without replacement. The characteristics of amino acid substitution in the HVR were not consistent with the random accumulation of mutations and imply that amino acid replacement in the HVR was strongly constrained. Another variable region of E2 centered on codon 60 shows similar constraints, while HVR2 was relatively unconstrained. Several of these features are difficult to explain if a neutralizing immune response against the HVR is the only selective force operating on E2. The impact of PCR artifacts such as nucleotide misincorporation and the shuffling of dissimilar templates is discussed.