Physiological role of Ca2+-permeable nonselective cation channel in endothelin-1-induced contraction of rabbit aorta

The alpha-amylase of Streptomyces sp. IMD 2679 was subject to catabolite repression. Four different growth rates were achieved when the organism was grown at 40 degrees C and 55 degrees C in the presence and absence of cobalt, with an inverse relationship between alpha-amylase production and growth rate. Highest alpha-amylase yields (520 units/ml) were obtained at the lowest growth rate (0.062 h-1), at 40 degrees C in the absence of cobalt, while at the highest growth rate (0.35 h-1), at 55 degrees C in the presence of cobalt, alpha-amylase production was decreased to 150 units/ml. As growth rate increased, the rate of specific utilisation of the carbon source maltose also increased, from 46 to 123 micrograms maltose (mg biomass)-1 h-1. The pattern and levels of alpha-glucosidase (the enzyme degrading maltose) detected intracellularly in each case, indicate that growth rate effectively controls the rate of feeding of glucose to the cell, and thus catabolite repression.     

Ventilation inhomogeneities and mixed venous blood N2 in multibreath N2 washout

OBJECTIVE: To examine the relationship between allergy-related symptoms, food intolerance and psychological distress in primary care. METHODS: Two thousand three hundred and thirty two adults in five General Practices in the South of England completed questionnaires regarding allergy-related symptoms and psychological symptoms, but no association was demonstrated between a history of diagnosed or treated asthma, eczema or hay fever and psychological morbidity. Cases of food intolerance had lower levels of psychological distress than expected compared to hospital samples. Current, but not past wheezing and eczema, was associated with an excess of life stresses in the previous six months. CONCLUSIONS: The association between psychological distress and the label of food allergy/intolerance found in specialist care does not extend to primary care.     

Cytokine and eosinophil responses in the lung, peripheral blood, and bone marrow compartments in a murine model of allergen-induced airways inflammation

Selective accumulation of eosinophils and activated CD4+ cells is now considered a central event in the pathogenesis of asthma, and this process is thought to be mediated by a number of cytokines including tumor necrosis factor-alpha (TNF-alpha), granulocyte-macrophage colony-stimulating factor (GM-CSF), and the Type 2 cytokines interleukin-4 (IL-4) and IL-5. To carry out a detailed time-course analysis of cellular changes in the bronchoalveolar lavage fluid (BAL), peripheral blood (PB), and bone marrow (BM), and of changes in the aforementioned cytokines in BAL and serum, Balb/c mice were sensitized by intraperitoneal injection with ovalbumin (OVA) adsorbed to aluminum hydroxide on two occasions 5 days apart, and were subjected to an OVA aerosol challenge 12 days after the second sensitization. This resulted in an airways inflammatory response characterized by early transient neutrophilia, marked eosinophilia, and, to a lesser extent, lymphocytosis in the BAL. Inflammatory events were first observed 3 h and 24 h after antigen challenge in the lung tissue and BAL, respectively, and lasted for 21 days. In the BM, we detected a 1.5- and 5-fold increase in the total number of cells and eosinophils, respectively, 4 days after the second sensitization. This was followed by a decrease, although BM eosinophilia remained clearly present at the time of antigen challenge. A second eosinopoietic event was observed in the BM shortly after challenge and reached a peak at day 3. BM cellularity returned to normal at day 21 after challenge. Serum OVA-specific IgE was first detected 3 days following the second sensitization (150 ng/ml). IgE levels then decreased but remained at the 75 ng/ml range at the time of the aerosol challenge. During the sensitization period, TNF-alpha (approximately 25 pg/ml), IL-4 (approximately 40 pg/ml), and IL-5 (approximately 250 pg/ml) were detected in serum, but not in the BAL fluid (BALF) and returned to background levels at the time of the antigen challenge. After antigen challenge, TNF-alpha, IL-4, IL-5, and GM-CSF were detected in serum. Peak levels were observed at 3 h (approximately 40 pg/ml), 3 h (approximately 120 pg/ml), 12 h (approximately 350 pg/ml), and 3 h (approximately 10 pg/ml), respectively, and returned to background levels 24 h after challenge. In the BALF, we detected peak levels of TNF-alpha, IL-4, IL-5, and GM-CSF at 6 h (approximately 250 pg/ml), 24 h (approximately 140 pg/ml), 24 h (350 pg/ml), and 3 h (approximately 10 pg/ml), respectively, with a return to background levels 5 days after challenge. No IL-10 could be detected at any time point during sensitization or after challenge in either serum or BAL. We also detected approximately 40 pg/ml of interferon-gamma (IFN-gamma) in the serum of normal untreated mice. Serum IFN-gamma levels fluctuated during sensitization and after challenge, but never exceeded those observed in untreated mice. Thus, the cytokine profile observed in this experimental model of allergic inflammation is characterized by IL-4 and IL-5 dominance, with an apparently minor TNF-alpha and GM-CSF contribution and relatively low or undetectable levels of IFN-gamma and IL-10.     

Upregulation of leptin receptor mRNA expression in obese mouse brain

Leptin receptor gene expression in the brains of lean (+/+) and obese (ob/ob) C57Bl/6 mice was examined using a non-radioactive in situ hybridization detection method. Significant increases in leptin receptor mRNA expression were found in the ventromedial and arcuate hypothalamic nuclei, piriform and olfactory cortices and medial habenular nucleus. There were very minor changes in the amount of leptin receptor mRNA expression in hippocampus proper (CA1-3). Results indicated that leptin receptor is upregulated when there is a lack of functional leptin, as in hereditary obese (ob/ob) mice. It is also suggested that leptin receptor may be an autoreceptor.     

6beta-Acetoxynortropane: a potent muscarinic agonist with apparent selectivity toward M2-receptors

A series of tropane derivatives, related in structure to baogongteng A (1), an alkaloid from a Chinese herb, were synthesized. 6beta-Acetoxynortropane (5) had weak affinity (Ki 22 microM) for central (M1) muscarinic receptors in a [3H]quinuclidinyl benzilate binding assay but had extremely high affinity (Ki 2.6 nM) and selectivity for M2-muscarinic receptors expressed in CHO cells. It had 13-fold lower affinity for M4-receptors, 260-fold lower affinity for M3-receptors, and 8200-fold lower affinity for M1-receptors expressed in CHO cells. The 6beta-carbomethoxy analogue (14) of baogongteng A had only weak affinity for M2-muscarinic receptors, as did 6beta-carbomethoxynortropane (13) and 6beta-acetoxytropane (4). In transfected CHO cells, 6beta-acetoxynortropane (5) was an agonist at M2-receptors, based on a GTP-elicited decrease in affinity, and a full agonist with an IC50 of 11 nM at M4-receptors, based on inhibition of cyclic AMP accumulation, while being a full agonist at M1-receptors with an EC50 of 23 nM and a partial agonist at M3-receptors with an EC50 of 3.6 nM, based in both cases on stimulation of phosphoinositide breakdown. All of the 16 tropane derivatives had weak affinities for central alpha4beta2-nicotinic receptors with 6beta-carbomethoxynortropane (13) having the highest affinity, which was still 150-fold less than that of nicotine. 6beta-Acetoxynortropane (5) represents a potent muscarinic agonist with apparent selectivity toward M2-receptors.     

Biological characteristics of Ligusticum chuanxiong Hort

Observational studies were conducted on the biological characteristics of Ligusticum chuanxiong, such as suitable growth environment, growing period, growth of stems, leaves and rhizomes, yield structure, etc. The specific regularities of each growth period were also studied.     

Effect of Paeonia lactiflora on platelet cytosolic free calcium and erythrocyte membrane Ca(2+)-Mg(2+)-ATPase activity in hyperlipid rabbits

The effect of Paeonia lactiflora (PL) on platelet cytosolic free calcium and erythrocyte membrane Ca(2+)-Mg(2+)-ATPase activity in hyperlipid rabbits were observed. Results showed the level of platelet cytosolic free calcium in the PL group (276.25 +/- 27.00 nmol/L) was significantly lower than that in the cholesterol group (390.88 +/- 70.00 nmol/L), P < 0.01, the basal and calmodulin-stimulated activities of erythocyte membrane Ca(2+)-Mg(2+)-ATP ase in PL group (0.79 +/- 0.05 mumol.pi-1.mg-1.h-1 and 1.34 +/- 0.10 mumol.pi-1.mg-1.h-1) were higher than that in the cholesterol group (0.65 +/- 0.09 mumol.pi-1.mg-1.h-1 and 1.04 +/- 0.13 mumol.pi-1.mg-1.h-1).     

Inhibition of experimental autoimmune encephalomyelitis in Lewis rats by nasal administration of encephalitogenic MBP peptides: synergistic effects of MBP 68-86 and 87-99

Induction of mucosal tolerance by inhalation of soluble peptides with defined T cell epitopes is receiving much attention as a means of specifically down-regulating pathogenic T cell reactivities in autoimmune and allergic disorders. Experimental autoimmune encephalomyelitis (EAE) induced in the Lewis rat by immunization with myelin basic protein (MBP) and Freund's adjuvant (CFA) is mediated by CD4+ T cells specific for the MBP amino acid sequences 68-86 and 87-99. To further define the principles of nasal tolerance induction, we generated three different MBP peptides (MBP 68-86, 87-99 and the non-encephalitogenic peptide 110-128), and evaluated whether their nasal administration on day -11, -10, -9, -8 and -7 prior to immunization with guinea pig MBP (gp-MBP) + CFA confers protection to Lewis rat EAE. Protection was achieved with the encephalitogenic peptides MBP 68-86 and 87-99, MBP 68-86 being more potent, but not with MBP 110-128. Neither MBP 68-86 nor 87-99 at doses used conferred complete protection to gp-MBP-induced EAE. In contrast, nasal administration of a mixture of MBP 68-86 and 87-99 completely blocked gp-MBP-induced EAE even at lower dosage compared to that being used for individual peptides. Rats tolerized with MBP 68-86 + 87-99 nasally showed decreased T cell responses to MBP reflected by lymphocyte proliferation and IFN-gamma ELISPOT assays. Rats tolerized with MBP 68-86 + 87-99 also had abrogated MBP-reactive IFN-gamma and tumor necrosis factor-alpha mRNA expression in lymph node cells compared to rats receiving MBP 110-128 nasally, while similar low levels of MBP-reactive transforming growth factor-beta and IL-4 mRNA expressing cells were observed in the two groups. Nasal administration of MBP 68-86 + 87-99 only slightly inhibited guinea pig spinal cord homogenate-induced EAE, and passive transfer of spleen mononuclear cells from MBP 68-86 + 87-99-tolerized rats did not protect na?ve rats from EAE. Finally, we show that nasal administration of MBP 68-86 + 87-99 can reverse ongoing EAE induced with gp-MBP, although higher doses are required compared to the dosage needed for prevention. In conclusion, nasal administration of encephalitogenic MBP peptides can induce antigen-specific T cell tolerance and confer incomplete protection to gp-MBP-induced EAE, and MBP 68-86 and 87-99 have synergistic effects. Non-regulatory mechanisms are proposed to be responsible for tolerance development after nasal peptide administration.