Application of in vivo microdialysis to pineal research in birds: Measurement of circadian rhythms of melatonin

Circadian rhythms of pineal melatonin release were measured in free-moving pigeons, Japanese quails, and chickens under light-dark cycles followed by constant dim light. Although melatonin levels differed among individual birds, circadian rhythms of melatonin were observed in all of them. Using this technique, we could examine phase shifts of melatonin rhythms and suppression of melatonin release by photic stimulation in pigeons. We could also examine effects of norepinephrine infusion on melatonin release. These results indicate that microdialysis is useful for the study of pineal melatonin rhythms in birds.     

Effects of lumbar skin warming on gastric motility and blood pressure in humans

We examined the possibility that lumbar skin warming can increase gastrointestinal motility by investigating the electrogastrogram (EGG), blood pressure, and heart rate with psychometric ratings in healthy humans. Scores of mood state profiles showed that lumbar skin warming (42 degrees C, 20 min) decreased tension-anxiety, depression, anger-hostility, fatigue, and confusion of the participants. A multiple bandpass filter analysis of EGGs showed that a postural transition from orthostatic to supine for measurement caused an increase in dominant frequency of 25-29% towards the frequencies of the normal interdigestive migrating motor complex (IMC). The spectral power of the IMC band, 2.55-3.05 cycles/min, was increased by 20 min-warming, reflecting the increase in gastric contractility. No increase in the spectral power was observed in the time-matched control group without skin warming. Therefore, an increase in contractility is a characteristic of lumbar skin warming. The systolic blood pressure increased by 15% during warm stimulation. Interbeat intervals were not influenced by warm stimulation. An analysis of interbeat intervals by a fast Fourier transform method showed that the cardiac sympathetic and parasympathetic nerves did not play a major role in raising the blood pressure. Vasoconstriction of the mesenteric artery was therefore considered to cause a blood pressure increase during warming. It is hypothesized that vasoconstriction of the visceral arteries by lumbar skin warming increases the blood pressure and gastrointestinal contractility.     

Isolation and phenogenetics of a novel circadian rhythm mutant in zebrafish

Widespread use of zebrafish (Danio rerio) in genetic analysis of embryonic development has led to rapid advances in the technology required to generate, map and clone mutated genes. To identify genes involved in the generation and regulation of vertebrate circadian rhythmicity, we screened for dominant mutations that affect the circadian periodicity of larval zebrafish locomotor behavior. In a screen of 6,500 genomes, we recovered 8 homozygous viable, semi-dominant mutants, and describe one of them here. The circadian period of the lager and lime (lag(dg2)) mutant is shortened by 0.7 h in heterozygotes,and 1.3 h in homozygotes. This mutation also shortens the period of the melatonin production rhythm measured from cultured pineal glands, indicating that the mutant gene product affects circadian rhythmicity at the tissue level, as well as at the behavioral level. This mutation also alters the sensitivity of pineal circadian period to temperature, but does not affect phase shifting responses to light. Linkage mapping with microsatellite markers indicates that the lag mutation is on chromosome 7. A zebrafish homolog of period1(per1) is the only known clock gene homolog that maps near the lag locus. However, all sequence variants found in per1 cDNA from lag(dg2) mutants are also present in wild type lines, and we were unable to detect any defect in per1 mRNA splicing, so this mutation may identify a novel clock gene.     

TNF microsatellite alleles a2 and b3 are not primarily associated with celiac disease in the Finnish population

Abstract: Recently, an independent association between tumor necrosis factor (TNF) gene polymorphism and ceiiac disease was observed in the Irish population. We tested this association in Finnish patients with celiac disease. The TNF microsatellite alleles a2 and b3 were strongly associated (P_corr<0.0001 for both) with celiac disease when the patients were compared to the random population. However, when the comparison was made with the DQ2-matched controls, no association could be found. We therefore conclude that in Finland the TNFa2 and b3 alleles are associated with DQ2-positive haplotypes rather than celiac disease.     

Genetic susceptibility to gluten sensitive enteropathy in Irish setter dogs is not linked to the major histocompatibility complex

Abstract: Gluten sensitive enteropathy (GSE) in Irish setter dogs has been proposed as an animal model for human celiac disease (CD), in which the major histocompatibility complex (MHC) class II alleles HLA DQAl*0501 and DQBl*0201 play an important role. To investigate whether an orthologous MHC class II region is involved in canine GSE, we undertook a linkage study in two large families of gluten sensitive Irish setter dogs. A total of 44 dogs in these pedigrees were genotyped for DQA1, DQB1 and C.2202 alleles, along with 30 unrelated healthy Irish setters. No genetic linkage between the DQ or C.2002 loci and GSE was detected. In contrast to CD, susceptibility to canine GSE does not appear to be determined by variation within the MHC class II gene cluster. Therefore, canine GSE may not be an appropriate model for CD, but nevertheless remains an important disease for advancing knowledge of pathological processes in the intestine.     

Inhibitory effect of methyl 7-butyl-4,5,6,7-tetrahydro-3-methylamino-4,6-dioxo-5-propyl-2H-pyrazolo [3,4-d] pyrimidine-2-carboxylate (AA-2379) on type III allergic (Arthus) reaction

Methyl 7-butyl-4,5,6,7-tetrahydro-3-methylamino-4,6-dioxo-5-propyl-2H-pyrazolo[3,4-d]pyrimidine-2-carboxylate (AA-2379), a non-steroidal, non-acidic agent, markedly inhibits type III allergic (Arthus) reaction; the ID₅₀ values of AA-2379 in the rat reversed passive Arthus pleurisy, the rat active Arthus pleurisy, and the reversed passive Arthus reaction in rat skin were 5–10 mg/kg, p.o., and 30 mg/kg of AA-2379 inhibited the active Arthus reaction in rabbit skin by about 50%. Dexamethasone, but not acidic non-steroidal anti-inflammatory drugs and aminopyrine, inhibited the Arthus reaction. The vascular permeability in the reversed passive Arthus pleurisy is enhanced biphasically in the early response mediated by physiologically active amines, prostaglandins, and leukotrienes, and in the late response mediated by complements and polymorphonuclear leukocytes (PMNs). AA-2379 inhibited the late response more potently than the early one. Furthermore, when given after the early response was reduced, AA-2379 obviously inhibited the late response. Rat zymosan-induced paw edema and mouse zymosan-activated serum-induced peritonitis, mediated by complements, were dose-dependently inhibited by AA-2379; the ID⁵⁰ values were 11.4 and 10.2 mg/kg, p.o., respectively. The results suggest that AA-2379 differes from non-steroidal anti-inflammatory agents in strongly inhibiting the late response of the Arthus reaction, which associated with PMNs.     

Identification of Goodpasture antigens in human alveolar basement membrane.

Goodpasture (GP) antigens, protein components reactive with human autoantibodies against glomerular basement membrane (GBM), were identified in human alveolar basement membrane (ABM) using an enzyme-linked immunoassay (ELISA), Western blotting and immunoprecipitation. All six anti-GBM antisera studied, three obtained from patients with glomerulonephritis and pulmonary haemorrhages (i.e. GP syndrome), and three from patients with glomerulonephritis alone, distinctively reacted with collagenase-digested (CD) ABM. Very cationic 22-28 kD and 40-48 kD components were detected by blot analysis combined with two-dimensional gel electrophoresis. These proteins showed some similarities to GP antigens in human GBM with respect to the monomer-dimer composition and charge distribution. Inhibition ELISA revealed that the binding of anti-GBM antisera to CDGBM decreased when they were pre-incubated with CDABM, suggesting that the anti-GBM antisera recognized the same epitope(s) on the GBM and ABM. Heterogeneity of the GP antigens in human ABM was demonstrated by blotting; monomeric antigens were absent or at low levels in the CDABM of three out of 10 normal individuals. In immunoprecipitation, anti-GBM antisera from patients with and without pulmonary haemorrhage showed different reactivities with CDABM. The former antisera precipitated both monomeric and dimeric components, but the latter did not. The observations of variation in monomer-dimer composition of ABM, and the different binding of anti-GBM antisera to it may explain why only some patients with anti-GBM nephritis have lung involvement.     

Ricinus communis agglutinin I blocks the binding of human anti-renal basement membrane antibodies to the kidney.

Whether or not glycosyl moieties of glycoproteins present in human renal basement membranes are related to the sites where anti-basement membrane antibodies bind was examined by blocking experiments using several kinds of lectin. Ricinus communis agglutinin I (RCA I), specific for galactose, blocked the binding of human anti-glomerular basement membrane (GBM) and anti-tubular basement membrane (TBM) antibodies to renal basement membranes. This lectin also diminished the binding of rabbit anti-laminin antibody, but did not inhibit the binding of mouse anti-fibronectin or rabbit anti-human TBM antibodies. These findings suggest that the binding sites of human anti-GBM and anti-TBM antibodies and heteroantibodies to laminin are closely related to the galactose moieties in glycoproteins of human renal basement membranes. Whether the galactose-containing branches are associated with the nephritogenicity of human anti-GBM and anti-TBM antibodies or simply exist adjacently to the antibody binding sites remains to be discerned.