An analog technique for recording leg position learning in the cockroach

A liquid chromatographic method is described for the determination of biogenic amines found in dry sausages: tryptamine, phenylethylamine, putrescine, cadaverine, histamine, serotonin, tyramine, spermidine, and spermine. Amines were extracted with perchloric acid solution and derivatized with dansyl chloride. After derivatization, ammonia was added to remove an interfering peak near cadaverine. Liquid chromatographic separations were performed by using a Spherisorb ODS2 column and an ammonium acetate-acetonitrile gradient elution program. The limits of determination of the individual amines were 1-5 mg/kg. This method is also applicable to detection of amines in other food samples.     

Development of the ultrastructural organization of the rat neurohypophysis during postnatal ontogenesis

The development of structural components of the posterior hypopysis lobe of rats, the development of the neurosecretory activity of the hypothalamo-hypophyseal nervous system and the establishment of its function as a single system within the first three weeks after birth (1, 7, 14 and 21 days) as well as embryos of the 20th and 21st days of development were studied electron-microscopically. It has been established that the pituicytes of the posterior lobe of the hypophysis of newborn rats are represented by a single type of cells and are completely differentiated. On the 21st day they are in different morpho-functional states and consist of dark and light cells. By the 14th day of development a considerably increased amount of the neurosecretion is observed. By the 21st day the density of neurosecretion granules per a preparation unit does not change. The basal layer of the capillaries is formed not definitely by the birth time; on the 14th day the organization of the vessel wall is almost similar to that of mature animals. The Herring bodies make their appearance on the 21st day after birth. The hypothalamus and neurohypophysis of rats are functionally active before birth. After birth their neurosecretion activity is well pronounced while the hypothalamo-hypophyseal nervous system is not mature yet. By the time of getting sight this system is almost formed and sufficiently active.     

A Flexible Univariate Autoregressive Time-Series Model for Dispersed Count Data

Integer-valued time series data have an ever-increasing presence in various applications (e.g., the number of purchases made in response to a marketing strategy, or the number of employees at a business) and need to be analyzed properly. While a Poisson autoregressive (PAR) model would seem like a natural choice to model such data, it is constrained by the equi-dispersion assumption (i.e., that the variance and the mean equal). Hence, data that are over- or under-dispersed (i.e., have the variance greater or less than the mean respectively) are improperly modeled, resulting in biased estimates and inaccurate forecasts. This work instead develops a flexible integer-valued autoregressive model for count data that contain over- or under-dispersion. Using the Conway–Maxwell–Poisson (CMP) distribution and related distributions as motivation, we develop a first-order sum-of-CMP's autoregressive (SCMPAR(1)) model that will instead offer a generalizable construct that captures the PAR, and versions of what we refer to as a negative binomial AR model, and binomial AR model respectively as special cases, and serve as an overarching representation connecting these three special cases through the dispersion parameter. We illustrate the SCMPAR model's flexibility and ability to effectively model count time series data containing data dispersion through simulated and real data examples.     

Ligand interactions with eukaryotic translation initiation factor 2: role of the gamma-subunit

Eukaryotic translation initiation factor 2 (eIF-2) comprises three non-identical subunits alpha, beta and gamma. In vitro, eIF-2 binds the initiator methionyl-tRNA in a GTP-dependent fashion. Based on similarities between eukaryotic eIF-2gamma proteins and eubacterial EF-Tu proteins, we previously proposed a major role for the gamma-subunit in binding guanine nucleotide and tRNA. We have tested this hypothesis by examining the biochemical activities of yeast eIF-2 purified from wild-type strains and strains harboring mutations in the eIF-2gamma structural gene (GCD11) predicted to alter ligand binding by eIF-2. The alteration of tyrosine 142 in yeast eIF-2gamma, corresponding to histidine 66 in Escherichia coli EF-Tu, dramatically reduced the affinity of eIF-2 for Met-tRNAi(Met) without affecting the k(off) value for guanine nucleotides. In contrast, non-lethal substitutions at a conserved lysine residue (K250) in the putative guanine ring-binding loop increased the off-rate for GDP, thereby mimicking the function of the guanine nucleotide exchange factor eIF-2B, without altering the apparent dissociation constant for Met-tRNAi(Met). For eIF-2[gamma-K250R], the increased off-rate also seen for GTP was masked by the presence of Met-tRNAi(Met) in vitro. In vivo, increasing the dose of the yeast initiator tRNA gene suppressed the slow-growth phenotype and reduced GCN4 expression in gcd11-K250R and gcd11-Y142H strains. These studies indicate that the gamma-subunit of eIF-2 does indeed provide EF-Tu-like function to the eIF-2 complex, and further suggest that the level of Met-tRNAi(Met) is critical for maintaining wild-type rates of initiation in vivo.     

Immune thrombocytopenic purpura in three patients with preexisting ulcerative colitis

Ulcerative colitis (UC) is associated with extraintestinal diseases in numerous target tissues. Associated immune-mediated hematological diseases, however, are rarely described. We report three Caucasian adult patients with UC and immune thrombocytopenic purpura (ITP). Platelet-associated antibodies (IgG) were positive in two patients, and bone marrow examinations in two patients revealed normal to increased megakaryocyte numbers. ITP was treated with corticosteroids in all patients. Two patients eventually received intravenous immune gamma-globulin, and one patient required surgical splenectomy. Of particular interest, UC preceded the onset of ITP in all patients (by from 1 to 19 yr). This suggests that ITP in these patients is causally associated with UC, possibly secondary to immunostimulation from lumenal antigens and altered immunoregulation.     

Changes in corticosteroid sensitivity of peripheral blood lymphocytes after strenuous exercise in humans

Although plasma corticosteroid concentrations can be measured accurately, the biological effect on the target tissue is uncertain. The availability of an accurate measure of corticosteroid sensitivity would potentially clarify the putative roles of endogenous glucocorticoids in illnesses such as inflammatory disease and obesity and allow evaluation of an additional regulatory level of glucocorticoid action. To measure corticosteroid sensitivity, we developed an assay based on the inhibition by dexamethasone (Dex) of lipopolysaccharide (LPS)-induced Interleukin-6 (IL-6) production and release in whole unseparated blood in vitro. LPS induced a dose-dependent increase in IL-6 concentrations up to 34 +/- 6.6 ng/mL, reaching plateau levels after 8 h, whereas Dex dose dependently inhibited LPS-induced IL-6 production. Involvement of the glucocorticoid receptor in this response was supported by abrogation of Dex (10(-7) mol/L) inhibition of IL-6 production by the glucocorticoid receptor antagonist RU 38486. To determine whether corticosteroid sensitivity is a dynamic phenomenon, we subjected healthy males to a graded quantifiable exercise associated with increases in plasma ACTH and cortisol. Before exercise, 3 x 10(-8) mol/L Dex inhibited LPS-induced IL-6 production in vitro; after exercise, 3 x 10(-8) and 10(-7) mol/L Dex were unable to inhibit IL-6 production. We conclude that Dex suppression of LPS-induced IL-6 production is an effective means of determining corticosteroid sensitivity, and that corticosteroid sensitivity in human subjects is a dynamic, rather than a static, phenomenon.