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The aim of this study was to evaluate whether the operational model of agonism can yield independent estimates of agonist affinity (pK(A)) and efficacy (log tau) when Furchgott's method of irreversible receptor inactivation is employed. For this purpose, the interaction between noradrenaline and phenoxybenzamine was studied in rat small mesenteric artery using a paired-curve design. Phenoxybenzamine pretreatment produced a significant rightward shift and depression of the upper asymptote of the noradrenaline concentration-effect (E/[A]) curve. Although the operational model of agonism appeared to provide an adequate fit of the individual E/[A] curves, a highly significant correlation was found between the estimates of pK(A )and log tau (r = -0.80, p < 0.0001), inconsistent with the assumption that affinity and efficacy are independent parameters (best line fit: pK(A) = -0.96 x log tau + 6.75). The pK(A) and log tau estimates were not correlated with either the pEC50s of the control curves or upper asymptotes of the phenoxybenzamine-treated curves. Simulations showed that the correlation between affinity and efficacy can be explained by the effect on the outcome of the analysis of random errors in the response measurements. Therefore, although in theory the operational model of agonism should provide independent estimates of agonist affinity and efficacy, this is unlikely to be the case with experimental data.

Using an enriched genomic library, we developed seven (CT)n/(GA)n microsatellite loci for eelgrass Zostera marina L. Enrichment is described and highly recommended for genomes in which microsatellites are rare, such as in many plants. A test for polymorphism was performed on individuals from three geographically separated populations (N = 15/population) and revealed considerable genetic variation. The number of alleles per locus varied between five and 11 and the observed heterozygosities for single loci ranged from 0.16 to 0.81 within populations. Mean allele lengths were markedly different among populations, indicating that the identified loci will be useful in studying population structure in Z. marina. As the frequency of the most abundant multilocus genotype within populations was always < 1%, these loci have sufficient resolving power to address clone size in predominantly vegetatively reproducing populations.

1. The exact nature of the receptor subtype(s) involved in the action of arg-vasopressin (AVP) on the rat aorta and small mesenteric artery (SMA) is controversial. Therefore, we have studied the effects of the selective V1A receptor antagonists, OPC 21268 and SR 49059, and the oxytocin (OT) receptor antagonist, atosiban, on the AVP- and OT-induced contractions of the two vessels. 2. AVP and OT displayed similar intrinsic activities in the rat aorta and SMA, but AVP was approximately 130 fold and approximately 500 fold more potent than OT, respectively. In the rat aorta, Hill slopes (nH) were similar for OT and AVP. However, in rat SMA, the OT concentration-effect (E/[A]) curve was significantly steeper than the AVP E/[A] curve (nH, = 3.3+/-0.20, 2.3+/-0.15; P<0.001). 3. In the aorta OPC 21268, SR 49059 and atosiban competitively antagonized the AVP and OT E/[A] curves. Except for atosiban and SR 49059 against AVP, competitive antagonism was also observed in the SMA. Atosiban caused concentration-dependent steepening of the AVP E/[A] curve, whereas SR 49059 decreased the upper asymptote. 4. Schild analysis yielded affinities indicative of V1A receptor involvement in both vessels: pKB/ pA2=9.20 9.48, 7.56 7.71 and 6.19 6.48 for SR 49059, OPC 21268 and atosiban, respectively. 5. Neither AVP nor OT relaxed U46619 pre-contracted aorta or SMA in the presence of SR 49059, suggesting no interference of a vasodilatory component. 6. Despite predominant involvement of V1A receptors in both vessels, the different Hill slopes of AVP and OT E/[A] curves as well as the steepening of the AVP E/[A] curves by atosiban are indicative of receptor heterogeneity in the rat SMA.

Amino acid sequences of alpha- and beta-chains of human hemoglobin and of hemoglobins of coelacanth and 24 teleost fish species, including 11 antarctic and two temperate Notothenioidei, were analyzed using maximum parsimony. Trees were derived for the alpha- and beta-chains separately and for tandemly arranged sequences, using the human and coelacanth sequences as outgroups in all analyses. The topologies of the trees of the alpha- and beta-chains are highly congruent and indicate a specific pattern of gene duplications and gene expression of teleost hemoglobins which has not yet been investigated into more detail. The Notothenioid fish generally contain a single major hemoglobin and often a second minor component. The alpha- and beta-chains of the major components form a monophyletic group in all investigated trees, with the nonantarctic Pseudaphritis as their sister taxon. The minor chains also are a monophyletic group and form an unresolved cluster with the major chains and the hemoglobins of tuna and red gurnard. The Notothenioid families Nototheniidae and Bathydraconidae appear to be paraphyletic.

We have studied the effects of benextramine on the U46619 (11 alpha,9 alpha-epoxymethano-15S-hydroxy-prosta-5Z,13E-dienoic acid)-mediated contraction of the rat isolated small mesenteric artery. U46619 (10 nM-10 microM) produced a concentration-dependent contraction of the small mesenteric artery. The selective prostanoid TP receptor antagonist, SQ 30,741 ([1S-[1 alpha,2 alpha(5Z),3 alpha,4 alpha]]-7- [[[[[(oxaheptyl)amino]acetyl]amino]-methyl]-7-oxabicyclo[2.2.1]hep t-2-yl]-5- heptenoic acid; 1 microM), produced a parallel, rightward shift of the U46619 curve with an associated pA2 value of 7.43 +/- 0.09. Treatment of tissues with 100 microM benextramine depressed the maximum response to U46619 in a time-dependent manner. However, neither SQ 30,741 (10 microM) nor U46619 (10 microM) incubation significantly protected against this effect. Thus, benextramine acts as an irreversible noncompetitive antagonist of U46619. The mechanism of this action is not yet clear.

Ribosomal DNA ITS sequences were compared among 13 different species and biogeographic isolates from the monophyletic "albida/sericea clade" in the green algal genus Cladophora. Six distinct ITS sequence types were found, characterized by multiple insertions and deletions and high levels of nucleotide substitution. Conserved domains within the ITS regions indicate the presence of ITS secondary structure. Low transition/transversion ratios among the six types and nearly symmetrical tree-length frequency distributions indicate some saturation, and low phylogenetic signal. Although branching order among five of the six ITS sequence types could not be resolved, estimates of ITS sequence divergence as compared with 18S divergence in a subset of the taxa suggests that the origin of the different ITS types is probably in the mid-Miocene (12 Ma ago) but that biogeographic isolates within a single ITS type (including both Pacific and Atlantic representatives) have probably dispersed on a time scale of thousands rather than millions of years.

Evolutionary relationships among species traditionally ascribed to the Siphonocladales/Cladophorales have remained unclear due to a lack of phylogenetically informative characters and extensive morphological plasticity resulting in morphological convergence. This study explores some of the diversity within the generic complex Cladophora and its siphonocladalaen allies. Twelve species of Cladophora representing 6 of the 11 morphological sections recognized by van den Hoek were analyzed along with 8 siphonocladalaen species using 18S rRNA gene sequences. The final alignment consisted of 1460 positions containing 92 phylogenetically informative substitutions. Weighting schemes (EOR weighting, combinatorial weighting) were applied in maximum parsimony analysis to correct for substitution bias. Stem characters were weighted 0.66 relative to single-stranded characters to correct for secondary structural constraints. Both weighting approaches resulted in greater phylogenetic resolution. Results confirm that there is no basis for the independent recognition of the Cladophorales and Siphonocladales. The Siphonocladales is polyphyletic, and Cladophora is paraphyletic. All analyses support two principal lineages, of which one contains predominantly tropical members including almost all siphonocladalean taxa, while the other lineage consists of mostly warm- to cold-temperate species of Cladophora.

In asthma, a beta-adrenoceptor dysfunction may be the consequence of an active disease state rather than a fundamental abnormality. In the present study the possible involvement of T lymphocytes in beta-adrenergic impairment was investigated by studying the effects of lymphocyte-derived mediators of beta-adrenoceptor function of human peripheral blood mononuclear cells (PBMCs) and guinea pig trachea. Supernatants of phytohemagglutinin- or concanavalin A-activated PBMCs from either persons with asthma or healthy persons inhibited isoprenaline stimulated cyclic adenosine 3',5'-monophosphate (cAMP) production of PBMCs after 20 hours of preincubation. These supernatants also inhibited beta-adrenoceptor function of PBMCs from patients with asthma to the same extent. The isoprenaline stimulated cAMP production of PBMCs was not altered after a 2-hour preincubation period with human interleukin-1 (IL-1), IL-2, IL-3, IL-4, granulocyte-macrophage colony-stimulating factor (GM-CSF) and interferon (IFN-gamma). In contrast, after 20 hours of preincubation, stimulated cAMP production of PBMCs was significantly diminished, with 63% by IL-1 (40 U/ml, p less than 0.01), with 36% by IL-2 (100 U/ml, p less than 0.05), with 37% by IFN-gamma (1000 U/ml, p less than 0.05), and with 21% by GM-CSF (100 U/ml, p less than 0.05). Preincubation of guinea pig tracheal segments with IL-1, IL-2, IL-4, or GM-CSF during 1 or 3 days did not affect the EC50 values or the maximal relaxation of isoprenaline dose response curves.

Acute uncomplicated UTI is one of the most common problems for which young women seek medical attention, and it accounts for considerable morbidity and health care costs. Acute cystitis is a superficial infection of the bladder mucosa, whereas pyelonephritis involves tissue invasion of the upper urinary tract. Localization tests suggest that as many as one third of episodes of acute cystitis are associated with silent upper tract involvement. Acute cystitis or pyelonephritis in the adult patient should be considered uncomplicated if the patient is not pregnant or elderly, if there has been no recent instrumentation or antimicrobial treatment, and if there are no known functional or anatomic abnormalities of the genitourinary tract. Most of these infections are caused by E. coli, which are susceptible to many oral antimicrobials. Because of the superficial nature of cystitis, single-dose and 3-day regimens have gained wide acceptance as the preferred methods of treatment. Review of the published data suggests that a 3-day regimen is more effective than a single-dose regimen for all antimicrobials tested. Regimens with trimethoprim-sulfamethoxazole appear to be more effective than those with beta-lactams, regardless of the duration. Acute pyelonephritis does not necessarily imply a complicated infection. Upper tract infection with highly virulent uropathogens in an otherwise healthy woman may be considered an uncomplicated infection. The optimal treatment duration for acute uncomplicated pyelonephritis has not been established, and 14-day regimens are often used. We prefer to use antimicrobials that attain high renal tissue levels, such as trimethoprim-sulfamethoxazole or quinolones, for pyelonephritis. Women with frequently recurring infections can be successfully managed by continuous prophylaxis, either daily or thrice-weekly, by postcoital prophylaxis, or, in compliant patients, by early self-administration of single-dose or 3-day therapy as soon as typical symptoms are noted. Our drug of choice for all these regimens is trimethoprim-sulfamethoxazole. Acute uncomplicated cystitis in adult men is very uncommon, but it is occasionally noted in homosexual men who practice insertive and intercourse or in heterosexual men whose partners have vaginal colonization with E. coli.

The effect of IL-2, IL-3, IL-4 and GM-CSF on beta-adrenoceptor function of human peripheral blood mononuclear cells (PBMC) was studied. After a 2 h pre-incubation period of PBMC with each of the lymphokines (1-100 units/ml), the isoprenaline stimulated cAMP production in these cells was not altered. However, IL-2 and GM-CSF induced a concentration dependent decrease of the beta-adrenoceptor agonist stimulated cAMP production after a 20 h pre-incubation period.