Larval development of Argentine hake Merluccius hubbsi.

The ontogeny of the developmental stages of the hake Merluccius hubbsi is described. Fish larvae and post-transitional juveniles were collected in the Nor-Patagonian area from 1989 to 2004. The opening of the mouth and the pigmentation of the eyes are coincident with yolk resorption, finishing the yolk-sac stage. This species presents pigmentation on the head, trunk and tail typical of gadiform larvae. Pectoral fin development is completed during the transformation stage. The post-transitional juvenile stage begins when the fin-ray complements are complete and squamation begins. The fins become fully formed in the following sequence: pelvic fins, first dorsal fin, second dorsal and anal fins together, caudal fin and pectoral fins. The caudal complex is totally developed in larvae of 22.0-23.0 mm standard lengths (L(S)) and all vertebral elements are first observed in larvae of 8.5 mm L(S). The rate of development of M. hubbsi observed in this study could be faster than the rates reported for other species of Merluccius by different authors.

Nitric oxide inhibits human and canine pulmonary vascular tone via a postjunctional, nonelectromechanical, cGMP-dependent pathway.

We examined nitric oxide mediated regulation of pulmonary arterial and venous smooth muscle (PASM and PVSM, respectively): whether this inhibition is mediated via prejunctional receptors on adrenergic nerve endings; whether NO is neuronally derived; the relationship between degree of inhibition and vessel size; and identification of the signalling mechanisms involved. Canine pulmonary vascular tissues were generally quiescent, while human PASM exhibited spontaneous phasic activity. The nitric oxide (NO) synthesis inhibitor Nomega-nitro-L-arginine (L-NNA; 10(-4) M) increased tone and enhanced phasic activity. Electrical field stimulation (EFS) evoked contractions were markedly enhanced by L-NNA in an endothelium-dependent fashion, and antagonized by the NO donor S-nitroso-N-acetylpenicillamine (SNAP; 10(-7) to 10(-5) M). 8-Bromo-cGMP mimicked the effects of SNAP on basal tone and EFS contractions, while an inhibitor of soluble guanylate cyclase mimicked those of L-NNA. While mechanical responses to exogenously added norepinephrine (10(-9)-10(-4) M) were also enhanced by L-NNA and suppressed by SNAP, EFS-evoked excitatory junction potentials were unaffected by SNAP. We conclude that, in human and canine PASM and PVSM, there is a tonic generation of NO originating within the endothelium that does not mediate a prejunctional effect, but which acts postjunctionally to activate a cGMP-dependent pathway within the smooth muscle.

Superficial buffer barrier and preferentially directed release of Ca2+ in canine airway smooth muscle.

We examined cytosolic concentration of Ca2+ ([Ca2+]i) in canine airway smooth muscle using fura 2 fluorimetry (global changes in [Ca2+]i), membrane currents (subsarcolemmal [Ca2+]i), and contractions (deep cytosolic [Ca2+]i). Acetylcholine (10(-4) M) elicited fluorimetric, electrophysiological, and mechanical responses. Caffeine (5 mM), ryanodine (0.1-30 microM), and 4-chloro-3-ethylphenol (0.1-0.3 mM), all of which trigger Ca2+-induced Ca2+ release, evoked Ca2+ transients and membrane currents but not contractions. The sarcoplasmic reticulum (SR) Ca2+-pump inhibitor cyclopiazonic acid (CPA; 10 microM) evoked Ca2+ transients and contractions but not membrane currents. Caffeine occluded the response to CPA, whereas CPA occluded the response to acetylcholine. Finally, KCl contractions were augmented by CPA, ryanodine, or saturation of the SR and reduced when SR filling state was decreased before exposure to KCl. We conclude that 1) the SR forms a superficial buffer barrier dividing the cytosol into functionally distinct compartments in which [Ca2+]i is regulated independently; 2) Ca2+-induced Ca2+ release is preferentially directed toward the sarcolemma; and 3) there is no evidence for multiple, pharmacologically distinct Ca2+ pools.

Effects of cromolyn and nedocromil on ion currents in canine tracheal smooth muscle.

Cromolyn and nedocromil are often used in the treatment of asthma. Recently, these agents have been shown to block Cl- currents and/or Ca2+ currents in a variety of cell preparations. Ca2+ and Cl- currents play central roles in excitation-contraction coupling in airway smooth muscle. This study therefore aimed to investigate the effects of these agents on membrane currents, elevations of [Ca2+] and contractions evoked by depolarization and/or acetylcholine in airway smooth muscle. Patch-clamp, fura-2 fluorimetric and muscle-bath techniques were used to monitor ion currents, [Ca2+] and contractions, respectively, in canine tracheal smooth muscle in the presence and absence of the chromones. Cromolyn and nedocromil eliminated voltage-dependent Ca2+ currents, leading to a reduction in depolarization-evoked K+ currents. Both chromones had little or no effect on either acetylcholine-evoked release of internal Ca2+ or the subsequent contraction; however, cromolyn (but not nedocromil) at high concentrations suppressed Ca2+-dependent Cl- currents triggered by acetylcholine. In conclusion, cromolyn and nedocromil abolished voltage-dependent Ca2+ currents and cromolyn also suppressed Ca2+-dependent Cl- currents in airway smooth muscle; neither chromone greatly altered either the release of internally sequestered Ca2+ or the resultant contractions. Further investigation is needed to determine whether the local concentrations obtained by inhaled chromones within the airway wall allow these cellular effects to occur in patients in vivo.

Intestinal effects of isoprostanes: evidence for the involvement of prostanoid EP and TP receptors.

The isoprostanes, which differ from prostaglandins by the cis orientation of their side chains, are believed to exert their biological effects on either a prostanoid TP receptor or a "unique" isoprostane receptor. Preliminary experiments suggested that canine colonic epithelium possessed no prostanoid TP receptor activity, in contrast to the muscularis mucosae, which responds well to the selective prostanoid TP receptor agonist U46619. To define the receptors involved, the in vitro responses of the epithelium and muscularis mucosae from the canine proximal colon to both 8-iso-PGE2 and 8-iso-PGF2alpha were compared. The epithelium responded to 8-iso-PGE2 but not to 8-iso-PGF2alpha. Under basal conditions, 8-iso-PGE2 produced concentration-dependent increases in short circuit current (pEC50 = 6.4 +/- 0.1) that were not antagonized by the selective prostanoid TP receptor antagonist SQ29548 (10(-6) M). Cross-desensitization experiments suggested that the stimulant effects involved a prostanoid EP receptor. Desensitization of the epithelium to PGE2 resulted in unexpected decreases in short circuit current in response to 8-iso-PGE2 (10(-6) M). This effect was mimicked by the selective prostanoid TP receptor agonist U46619 (10(-5) M), and antagonized by three structurally different prostanoid TP receptor antagonists: L670596 (10(-6) M), SQ29548 (10(-6) M) and GR32191 (10(-6) M). 8-Iso-PGE2, 8-iso-PGF2alpha and U46619 caused concentration-dependent increases in the force of contraction of the muscularis mucosae strips. These responses were antagonized by selective prostanoid TP receptor antagonists, arguing for the involvement of prostanoid TP receptors. Thus, the effects of isoprostanes on the canine colon involve both prostanoid TP and EP receptors.

Effects of a selective DP receptor agonist (BW 245C) and antagonist (BW A868C) on the canine colonic epithelium: an argument for a different DP receptor?

Earlier studies showed that PGD2 produced both increases and decreases in short-circuit current across the canine proximal colon. PGD2 metabolites had opposing effects: 11 beta-PGF2 alpha elicited only increases in Isc, and 13,14-dihydro-15-keto-PGD2 elicited only decreases. The stimulant effects involved FP receptors, but the receptors involved in mediating the inhibitory effects remained undefined. Here we show that the tissue, although it is capable of producing both PGD2 and PGE2, did not produce 11 beta-PGF2 alpha in measurable amounts. The selective DP receptor agonist BW 245C did not mimic the inhibitory effects of PGD2, producing only dose-dependent increases in short-circuit current. Further, these responses were not significantly inhibited by BW A868C. Cross-desensitization experiments suggested that the stimulant effects of BW 245C involved the EP receptor. However, on a standard preparation (rabbit platelets), both PGD2 and BW 245C inhibited ADP-induced aggregation and were antagonized by BW A868C. 11 beta-PGF2 alpha had no effects. The decreases in short-circuit current across the canine colonic epithelium elicited by PGD2 and 13,14-dihydro-15-keto PGD2 are not mimicked by other prostanoids, nor by the selective agonist BW 245C, and thus appear to involve receptors other than the classical DP receptor.

Smooth muscle from aganglionic bowel in Hirschsprung's disease impairs neuronal development in vitro.

Hirschsprung's disease results from the congenital absence of enteric neurons in human distal colon. The reason for aganglionosis is unknown but may reflect an unfavourable microenvironment for neuronal development. We asked if smooth muscle cells from the anganglionic region could affect neuronal development in vitro. Neurons from neonatal mouse superior cervical ganglia were added to cultures of smooth muscle obtained from normal or aganglionic regions of five patients with Hirschsprung's disease. Although neurons initially showed more rapid attachment to aganglionic smooth muscle, this was equal by 60 min and thereafter. Progressive increase in the diameter of the nerve cell body was characteristic of normal maturation in vitro. This was consistently inhibited by 15-22% in neurons grown on aganglionic muscle compared with normal controls over the 6-day test period (P < 0.05). This phenomenon was preserved when the smooth muscle cells were lysed by brief exposure to distilled water before initiation of co-culture (16-18% inhibition; P < 0.05). These data imply that smooth muscle of the aganglionic colon is less favourable for neuronal development than the normally innervated region and suggest a membrane-linked factor. Clearly, this persists in postnatal life and in vitro and may reflect an abnormality of cellular interaction causing Hirschsprung's disease.

Biological activity of metabolites of PGD2 on canine proximal colon.

The responses of the canine colonic epithelium to the metabolites of prostaglandin D2 (PGD2) were compared with those elicited by the parent prostanoid. Dose-response relations to PGD2 showed three distinct patterns: 1) a dose-dependent decrease in short-circuit current (Isc) at lower concentrations followed by a dose-dependent increase at higher concentrations; 2) dose-dependent decreases, with no increase even at the highest concentrations tested; and 3) dose-dependent increases in Isc, with no decreases at any concentration. The colon responded differently to the two enzymatically derived metabolites 13,14-dihydro-15-keto-PGD2 (DK) and 11 beta-PGF2 alpha. The former consistently produced only dose-dependent decreases in Isc, while the latter elicited only dose-dependent increases. Pretreatment of tissues with 11 beta-PGF2 alpha altered the responses to PGD2 such that only decreases were noted. Conversely, pretreatment with DK caused PGD2 to elicit only increases in Isc. The nonenzymatically derived PGJ2 elicited responses comparable to those seen with PGD2. Pretreatment of tissues with indomethacin abolished responses to 11 beta-PGF2 alpha as well as its isomer, PGF2 alpha, suggesting the involvement of a cyclooxygenase product. Responses to PGE2 were, however, amplified. Cross-desensitization was noted between the two isomers. Tissues desensitized to either 11 beta-PGF2 alpha or PGF2 alpha were responsive to DK as well as PGE2; however, tissues desensitized to PGE2 were unresponsive to 11 beta-PGF2 alpha. Thus the canine colonic epithelium responds not only to PGD2 but also to its derived metabolites. Variability in the response to PGD2 between animals could stem from differences at the receptor level and/or differential production of these metabolites.

Primary lymphoplasmacytic lymphoma of the larynx: a rare localization of MALT-type lymphoma.

Laryngoscopy carried out in a 46-year-old man revealed a left paralaryngeal tumor. The mass was entirely removed by left pharyngolaryngotomy. Microscopic study showed a diffuse malignant lymphoma of low-grade malignancy, exhibiting all the criteria of the MALT-type lymphoma: the proliferation of centrocyte-like and lymphoplasmacytic cells, lymphoepithelial lesions, and the presence of germinal centers. Primary lymphoma of the larynx is a rare condition. Most of the reported low-grade lymphomas and the pseudolymphomas probably belong to the category of MALT-type lymphoma. Remission can be obtained by surgery, radiotherapy, and polychemotherapy.

Results in two infants with the DiGeorge syndrome--effects of long-term TP5.

We treated two patients affected by DiGeorge syndrome with long-term administration of the synthetic thymic hormone thymopoietin (TP5). In both cases we obtained durable immunological reconstitution, starting as early as 2 weeks after beginning of TP5 treatment. High levels of circulating immature thymocytes and precursor T cells (defined by monoclonal antibodies OKT6, OKT9, and OKT10) were present prior to therapy, and they steadily decreased during the first few weeks of study. During the same time, phenotypically mature T lymphocytes (OKT3+ and OKT4+/OKT8+) markedly increased, thereafter remaining at near normal levels. OKT10+ cells appeared to rise again after 3 months of TP5 treatment. In vitro function of T cells, assessed by PHA stimulation, and in vivo cell-mediated immunity (skin tests with Candida) were normal at 3 and at 2 months, respectively, after initiation of therapy. No severe infection episodes were recorded and normal development was achieved. No side effect or adverse reaction occurred. In these two patients the other features of the DiGeorge syndrome were successfully treated by early cardiac surgery and vitamin D therapy. The immunological reconstitution, in absence of functioning thymus observed in these two cases, provides further evidence of the effectiveness of long-term treatment with thymic hormones--with maintenance of the improvement of cell-mediated immunity.

Current concepts on the relationship between immunodeficiency and allergy.

The relationship between immunodeficiency and atopy represent one of the most significant yet at the same time one of the least understood phenomena in medicine today. This paper will therefore attempt to review the present state of knowledge. Current data focusing on the role of histamine as a negative feed-back regulator of the immune system will also be summarized. It has recently become evident that although several lines of evidence have documented abnormal suppressor T cell functions or numbers in the atopic state, the exact mechanism, however, is not clear yet. It would be important to assess whether the disturbed T cell activity is primary or secondary to the other findings in the atopic diathesis.

IgE levels and PMN chemotaxis in atopic dermatitis.

In the recent years immunological abnormalities, including defective polymorphonuclear neutrophils (PMN) chemotaxis and both quantitative and functional defects in T-lymphocytes, have been reported in atopic dermatitis (AD). To date there is still a controversy regarding the causes of PMN chemotaxis defect and the possible mechanism underlying this abnormality in patients with AD. The aim of this study was to investigate the PMN chemotactic function in 18 children affected with AD and high levels of serum IgE, and in 4 children with Hyper IgE Syndrome (HIES). Our results showed a marked PMN chemotaxis defect (p less than 0.01) in the patients with HIES, while in the subjects with AD PMN cellular chemotaxis was normal and there was no correlation between the results of chemotaxis and serum IgE levels.