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At least 1,261 records · Page 70Linked to original sources
PubMed1984

Impulse activity differentially regulates [Leu]enkephalin and catecholamine characters in the adrenal medulla.

Regulation of the putative peptide neurohumour [Leu]enkephalin and the catecholaminergic enzymes tyrosine hydroxylase and phenylethanolamine-N-methyl-transferase was examined in the rat adrenal medulla in vivo and in vitro. Surgical denervation of the adrenal gland or pharmacologic blockade of synaptic transmission, treatments known to decrease catecholamine traits, increased [Leu]enkephalin content. Medullas explanted to culture exhibited a 50-fold rise in [Leu]enkephalin in 4 days, whereas tyrosine hydroxylase remained constant, and phenylethanolamine-N-methyltransferase decreased to a new baseline level. Veratridine-induced depolarization prevented the accumulation of [Leu]enkephalin, an effect that was blocked by tetrodotoxin, which antagonizes transmembrane Na+ influx. These studies suggest that enkephalinergic and catecholamine characters are differentially regulated by impulse activity and depolarization in the adrenal medulla.

Adrenal Medulla↗
PubMed1982

Spectral character of sunlight modulates photosynthesis of previtamin D3 and its photoisomers in human skin.

The photosynthesis of previtamin D3 from 7-dehydrocholesterol in human skin was determined after exposure to narrow-band radiation or simulated solar radiation. The optimum wavelengths for the production of previtamin D3 were determined to be between 295 and 300 nanometers. When human skin was exposed to 295-nanometer radiation, up to 65 percent of the original 7-dehydrocholesterol content was converted to previtamin D3. In comparison, when adjacent skin was exposed to simulated solar radiation, the maximum formation of previtamin D3 was about 20 percent. Major differences in the formation of lumisterol3, and tachysterol3 from previtamin D3 were also observed. It is concluded that the spectral character of natural sunlight has a profound effect on the photochemistry of 7-dehydrocholesterol in human skin.

Cholecalciferol↗
PubMed2000

Imaging the enzymatic digestion of bacterial cellulose ribbons reveals the endo character of the cellobiohydrolase Cel6A from Humicola insolens and its mode of synergy with cellobiohydrolase Cel7A.

Dispersed cellulose ribbons from bacterial cellulose were subjected to digestion with cloned Cel7A (cellobiohydrolase [CBH] I) and Cel6A (CBH II) from Humicola insolens either alone or in a mixture and in the presence of an excess of beta-glucosidase. Both Cel7A and Cel6A were effective in partially converting the ribbons into soluble sugars, Cel7A being more active than Cel6A. In combination, these enzymes showed substantial synergy culminating with a molar ratio of approximately two-thirds Cel6A and one-third Cel7A. Ultrastructural transmission electron microscopy (TEM) observations indicated that Cel7A induced a thinning of the cellulose ribbons, whereas Cel6A cut the ribbons into shorter elements, indicating an endo type of action. These observations, together with the examination of the digestion kinetics, indicate that Cel6A can be classified as an endo-processive enzyme, whereas Cel7A is essentially a processive enzyme. Thus, the synergy resulting from the mixing of Cel6A and Cel7A can be explained by the partial endo character of Cel6A. A preparation of bacterial cellulose ribbons appears to be an appropriate substrate, superior to Valonia or bacterial cellulose microcrystals, to visualize directly by TEM the endo-processivity of an enzyme such as Cel6A.

Aspergillus niger↗
PubMed1969

Correlations between virulence and other characters of Clostridium perfringens type A.

The correlation analysis which has already proved its value in ecology has not yet been applied to the determination of virulence indicators. Its application to a group of Clostridium perfringens type A strains has brought out some characters that may be considered as virulence indicators. This study suggests that the toxicity of the culture supernatant fluids for mice is significantly correlated with the virulence for mice and guinea pigs. A significant correlation was found between the virulence of the fluid cultures for mice or guinea pigs and the coagulation of milk, production of gas (in deep agar), hydrogen sulfide production, and fermentation of glucose, sucrose, maltose, and levulose.

Animals↗
PubMed1978

Inhibition of Bacillus subtilis spore germination by various hydrophobic compounds: demonstration of hydrophobic character of the L-alanine receptor site.

L-Alanine-initiated germination of Bacillus subtilis spores was inhibited by various kinds of hydrophobic compounds. Good correlation of inhibitory effect with hydrophobicity of the compound was demonstrated by using regression analysis in which the hydrophobic character was expressed by the partition coefficient in an octyl alcohol-water system. The correlation coefficient for 20 alcohols was 0.959, and that for 19 miscellaneous compounds was 0.906. Regression lines of the alcohols and other hydrophobic compounds were almost identical, showing that hydrophobic interaction played an important role in inhibition. Diphenylamine was one of the most effective inhibitors examined. n-Octyl, n-nonyl, and n-decyl alcohols were the most effective alcohols. The mode of inhibition by diphenylamine and n-octyl alcohol was a "mixed type" (competitive plus noncompetitive type) with respect to L-alanine; that by D-alanine was competitive inhibition. Sites for diphenylamine, n-octyl alcohol, and D-alanine may have overlapped. Inhibition was reversible by washing; heat resistance, stainability, and germination rate of the washed spores remained unaltered. Thus, we confirmed that the inhibition may occur before the initial trigger reaction of germination and that it may be due to the interaction between a hydrophobic compound and a hydrophobic region closely associated with the L-alanine receptor site on the spore.

Alanine↗
PubMed1964

GENETIC LINKAGE OF MUTATIONAL SITES AFFECTING SIMILAR CHARACTERS IN PNEUMOCOCCUS AND STREPTOCOCCUS.

Ravin, Arnold W. (University of Rochester, Rochester, N.Y.), and Joscelyn D. H. De Sa. Genetic linkage of mutational sites affecting similar characters in pneumococcus and streptococcus. J. Bacteriol. 87:86-96. 1964.-By interspecific transformation, deoxyribonucleic acid (DNA) determinants conferring resistance to high levels of streptomycin in pneumococcus were found to be allelic with DNA determinants conferring low levels of streptomycin resistance in the Challis and NBSI strains of streptococcus. The reciprocal transformation (low resistance pneumococcus x high resistance streptococcus) led to the same conclusion. In addition, determinants controlling resistance to erythromycin in pneumococcus and the Challis strain of streptococcus were found to become closely linked after interspecific transformation. Modifier genes influencing the phenotype conferred by mutations at the streptomycin-resistance locus differentiate species to a certain extent. The results demonstrate that transformations between pneumococcus and streptococcus are not due to episomes, but involve recombinational events in which genetic material of the host species is replaced by homologous material that performed a similar function in the donor species.

DNA↗
PubMed1981

Diagnostic characters of an atypical Candida.

The morphological and physiological characters of an atypical Candida isolated from diverse clinical specimens are described. The colony and microscopic morphologies of the atypical Candida most closely resemble those of Candida tropicalis or of reported sucrose-negative variants of C. tropicalis. However, the atypical isolates differ from C. tropicalis by their inability to ferment sucrose or melezitose and from the sucrose-negative variants by their inability to assimilate inulin and their varied utilization of other carbon substrates.

Candida↗
PubMed1988

Drosophila S virus, a hereditary reolike virus, probable agent of the morphological S character in Drosophila simulans.

Isometric reolike virions were found in all the examined Drosophila simulans flies from two strains (SimES-st and Israel-st) presenting the S phenotype, a maternally inherited morphological trait (abnormalities of bristles). Normal flies of both strains appeared virus-free. Virions were found in the cytoplasm of male and female gonads and epidermal cells, including the bristle-forming cells, which appeared disorganized. Steps of virogenesis were described. A positive correlation was demonstrated between expressivity of the S phenotype and degree of viral infection. This hereditary reolike virus seems to be responsible for the S character of D. simulans and was named DSV (Drosophila S virus).

Animals↗
PubMed1995

High dependency units in the UK: variable size, variable character, few in number.

An exploratory descriptive survey was conducted to determine the size and character of high dependency units (HDUs) in the UK. A telephone survey and subsequent postal questionnaire was sent to the 39 general HDUs in the UK determined by a recent survey from the Royal College of Anaesthetists; replies were received from 28. Most HDUs (82%, n = 23) were geographically distinct from the intensive care unit and varied in size from three to 13 beds, although only 64% (n = 18) reported that all beds were currently open. Nurse: patient ratios were at least 1:3. Fifty per cent of units had one or more designated consultants in charge, although only 11% (n = 3) had specifically designated consultant sessions. Junior medical cover was provided mainly by the on-call speciality term. Twenty units acted as a step-down facility for discharged intensive care unit patients and 21 offered a step-up facility for patients from general wards. Provision of facilities and levels of monitoring varied between these units. Few HDUs exist in the UK and they are variable in size and in the facilities and monitoring procedures which they provide. Future studies are urgently required to determine cost-effectiveness and outcome benefit of this intermediate care facility.

Health Facility Size↗
PubMed2002

Relationship between bacterial colonisation and the frequency, character, and severity of COPD exacerbations.

BACKGROUND: Patients with chronic obstructive pulmonary disease (COPD) are prone to frequent exacerbations which are a significant cause of morbidity and mortality. Stable COPD patients often have lower airway bacterial colonisation which may be an important stimulus to airway inflammation and thereby modulate exacerbation frequency. METHODS: Twenty nine patients with COPD (21 men, 16 current smokers) of mean (SD) age 65.9 (7.84) years, forced expiratory volume in 1 second (FEV(1)) 1.06 (0.41) l, FEV(1) % predicted 38.7 (15.2)%, FEV(1)/FVC 43.7 (14.1)%, inhaled steroid dosage 1.20 (0.66) mg/day completed daily diary cards for symptoms and peak flow over 18 months. Exacerbation frequency rates were determined from diary card data. Induced sputum was obtained from patients in the stable state, quantitative bacterial culture was performed, and cytokine levels were measured. RESULTS: Fifteen of the 29 patients (51.7%) were colonised by a possible pathogen: Haemophilus influenzae (53.3%), Streptococcus pneumoniae (33.3%), Haemophilus parainfluenzae (20%), Branhamella catarrhalis (20%), Pseudomonas aeruginosa (20%). The presence of lower airway bacterial colonisation in the stable state was related to exacerbation frequency (p=0.023). Patients colonised by H influenzae in the stable state reported more symptoms and increased sputum purulence at exacerbation than those not colonised. The median (IQR) symptom count at exacerbation in those colonised by H influenzae was 2.00 (2.00-2.65) compared with 2.00 (1.00-2.00) in those not colonised (p=0.03). The occurrence of increased sputum purulence at exacerbation per patient was 0.92 (0.56-1.00) in those colonised with H influenzae and 0.33 (0.00-0.60) in those not colonised (p=0.02). Sputum interleukin (IL)-8 levels correlated with the total bacterial count (rho=0.459, p=0.02). CONCLUSION: Lower airway bacterial colonisation in the stable state modulates the character and frequency of COPD exacerbations.

Aged↗
PubMed1981

Genetic analysis of quantitative characters in cigar and pipe tobacco Nicotiana tabacum II. Grades of cigar filler tobacco.

A diallel cross of four cigar and one pipe tobacco (Nicotiana tabacum L.) was analyzed for the following characters in samples of cured tobacco: (1) percentage of light filler; (2) percentage of heavy filler; (3) percentage of top filler; (4) percentage of bottom filler; (5) percentage of total filler; (6) percentage of marketable trash and (7) total percentage of marketable tobacco. The experiment was performed over three years with four replications. Analysis was done for general combining ability and specific combining ability. General combining ability was greater than specific combining ability for all parameters, although specific combining ability effects were also present for all parameters with the exception of total marketable tobacco. Reciprocal effects were completely absent. The line Pennbel 69 showed a negative general combining ability effect for all grades of filler, total filler and total marketable tobacco with a positive effect for percentage of marketable trash. High positive specific combining ability effects for percentage total filler and high negative specific combining ability effects for percentage marketable trash were shown by crosses of Pennbel 69 with the other four cultivars.

Plants↗
PubMed1984

Effect of experimental dysthyroidism on the enzymatic character of the diaphragm.

This study examined the effects of long-term experimental dysthyroidism on the enzymatic character of the costal diaphragm and selected respiratory parameters. Costal diaphragms from thyroidectomized (TX), euthyroid (EU), and hyperthyroid (HT) male albino rats were used. HT was induced by subcutaneous injections of triiodothyronine on alternate days for 6 wk. Minute ventilation was greater for the HT (70%) compared with the TX rats. The enzymatic potentials of glycolysis (28%), tricarboxylic acid cycle (30%), and fatty acid oxidation (16%) were significantly increased in the HT diaphragms, whereas the potentials were lower by a similar relative extent in the TX diaphragms. The proportion of alkali-labile fibers were greater in the TX and lower in the HT diaphragm. The shifts in heart and muscle lactate dehydrogenase isoenzyme activities were consistent with the fiber type changes. These findings show that dysthyroidism modifies the overall enzymatic capacity of the diaphragm (i.e., glycolysis, tricarboxylic acid cycle, and fatty acid oxidation) along with the proportion of alkali-labile to alkali-stable fiber types. These enzymatic changes are similar to those resulting from exercise training, tracheal banding, streptozotocin diabetes, and emphysema.

Animals↗
PubMed1998

Mechanosensitive pelvic nerve afferent fibers innervating the colon of the rat are polymodal in character.

This report describes the chemical and thermal sensitivity of mechanosensitive pelvic nerve afferent fibers innervating the colon of the rat. A total of 51 fibers in the S1 dorsal root, identified by electrical stimulation of the pelvic nerve, were studied. An approximately 7 cm length of descending colon was isolated in situ to permit intracolonic perfusion and distension with Krebs solution. Reproducibility of responses to repetitive colorectal distension (CRD, 40 mmHg, 30 s, every 4 min) was documented. All fibers gave monotonic, incrementing responses to graded CRD (5 to 60 mmHg). Increases (n = 6) or decreases (n = 6) in pH of the perfusate failed to produce any change in resting activity or responses to CRD. Infusion of bile salts increased the resting activity of 6/6 fibers in a concentration-dependent manner, but did not affect the magnitude of responses to CRD. After intracolonic instillation of an inflammatory soup (bradykinin 10(-5) M, PGE2 10(-5) M, serotonin 10(-5) M, histamine 10(-5) M and KCl 10(-3) M), 13/22 fibers exhibited sensitization of responses to CRD. Seventy-three percent of 45 fibers tested responded to intracolonic perfusion of heated Krebs solution. The estimated threshold for response was 45 degreesC and response magnitude increased with the temperature. A smaller proportion (30%) of 37 fibers tested responded to intracolonic perfusion of cold Krebs solution. The estimated threshold for response was 28 degreesC. Of 36 fibers tested, 8 were activated by both heat and cold; typically, fibers activated by heat did not respond to cold. In a sample of 26 fibers tested for response to all three modalities of stimulation, 11 responded to mechanical, chemical and thermal stimuli; the remaining 15 responded to mechanical and either chemical or thermal stimulation. Changes in intracolonic pressure in response to chemical and thermal stimuli were also evaluated. Inflammatory soup and bile salts did not change intracolonic pressure; heat and cold produced a modest decrease and increase in muscle tension, respectively. These results document that mechanosensitive pelvic nerve afferent fibers are also chemosensitive and/or thermosensitive, supporting the notion that visceral mechanoreceptors in general are likely polymodal in character.

Action Potentials↗
PubMed1998

Crustacean-insect relationships: the use of brain characters to derive phylogeny amongst segmented invertebrates.

Conserved neural characters identified in the brains of a variety of segmented invertebrates and outgroups have been used to reconstruct phylogenetic relationships. The analysis suggests that insects and crustaceans are sister groups and that the 'myriapods' are an artificial construct comprising unrelated chilopods and diplopods. Certain elements of the optic lobes and mid-brain support the notion that insects are more closely related to crustaceans than they are to any other arthropods. However, deep optic neuropils and optic chiasmata are homoplastic in insects and crustaceans. The organization of olfactory pathways suggests that insect olfactory lobes originated late, probably first appearing in orthopteroid or blattoid pterygotes. The present results are discussed with respect to recent studies on early development of arthropod nervous systems and the fossil record.

Animals↗
PubMed2001

Polymorphisms in the dopamine, serotonin, and norepinephrine transporter genes and their relationship to temperamental dimensions measured by the Temperament and Character Inventory in healthy volunteers.

There is evidence for an association between polymorphisms of monoamine transporter genes and temperamental personality traits. Recent findings have shown that interaction of allelic variants of the different genes may contribute to the personality factors. We studied the association between temperamental personality dimensions measured with the Temperament and Character Inventory (TCI) and polymorphisms of the dopamine (DAT), norepinephrine (NET) and serotonin (5-HTT) transporter genes in 127 healthy Polish volunteers. There were no significant differences between means of TCI temperamental dimensions (novelty seeking, reward dependence, persistence and harm avoidance) and the transporter genes compared by ANOVA. There were some significant associations between genotypes and TCI subdimensions. Individuals carrying the A9/A9 DAT genotype have lower RD4 scores (dependence vs. independence) than A10/A10 individuals (3.0 +/- 1.4 vs. 3.5 +/- 1.3); p = 0.01. Examining 5-HTT gene promoter polymorphism, heterozygous individuals (l/s) and individuals with 44-bp deletion (s/s) scored significantly lower in the HA1 subdimension (anticipatory worry and pessimism vs. uninhibited optimism; 4.3 +/- 2.3 vs. 5.5 +/- 2.6) in comparison with individuals without deletion (l/l); p = 0.021. The NET transporter gene polymorphism showed no significant association with any of the temperamental TCI subdimensions.

Adult↗
PubMed2005

Temperament and character in mood disorders: influence of DRD4, SERTPR, TPH and MAO-A polymorphisms.

Gene variants exert a complex range of effects on human normal and abnormal behavior. We previously reported the effect of gene variants in serotoninergic and dopaminergic pathways, in a range of clinical features in mood disorders, such as symptomathology, periodicity, social adjustment and treatment response. In this paper we hypothesized that the same gene variants could influence temperamental traits in mood disorders patients. We focused on genes of the serotoninergic and dopaminergic systems (dopamine receptor D4 gene, DRD4; serotonin transporter gene, promoter region SERTPR; tryptophan hydroxylase gene, TPH; monoamine oxidase A gene, MAO-A). Two hundred and seven euthymic subjects, affected by major depressive disorder (n=73) and bipolar disorder (n=134) were assessed by the Cloninger's Temperament and Character Inventory (TCI) and typed using PCR-based analyses. Possible stratification factors such as demographic, clinical and other temperamental factors were also taken into account. We observed that homozygosity for the short SERTPR allele was associated with low novelty-seeking scores (p=0.006) and genotypes containing the DRD4 long allele were marginally associated with low harm avoidance (p=0.05). Finally, the long MAO-A allele was associated with decreased persistence scores among females (p=0.006). Our observation of a pattern of influence on temperamental dimension exerted by serotonergic and dopaminergic genes suggests that the contribution of these polymorphisms to the clinical presentation of mood disorders could be mediated by an influence on personality differences.

Adult↗