Different modulation by histamine of IL-4 and interferon-gamma (IFN-γ) release according to the phenotype of human Th0, Th1 and Th2 clones

Histamine, an important inflammatory mediator in allergic diseases and asthma, has been reported to have modulator effects on T cells, suggesting that the bronchial microenvironment may regulate the function of resident T cells. We examined the effect of histamine on the release of the Th2-associated cytokines IL-4 and IL-5 and the Th1-associated cytokine IFN-γ by 30 CD4⁺ T cell clones from peripheral blood or bronchial biopsy of one atopic subject. Based on the IL-4/IFN-γ ratio, the clones were ascribed to the Th2 (ratio >1), Th0 (ratio 0.1 and 1) or Th1 (ratio <0.1) phenotype. Histamine inhibited IFN-γ production by Th1-like cells (P<0.02, Kruskall–Wallis), especially from bronchial biopsy, but had no effect on IL-4 release. Regarding Th0 clones, histamine inhibited IL-4 production (P<0.02) in a dose-dependent manner and slightly inhibited IFN-γ production, but had no effect on Th2-like cells. Histamine had a heterogeneous and insignificant effect on IL-5 production. The H₂-receptor antagonist ranitidine completely reversed the inhibition of IL-4 and IFN-γ production, whereas the agonist dimaprit mimicked this effect. In contrast, H₁- and H₃-receptor agonists and antagonists had no significant effect. These data demonstrate that histamine has different effects on IL-4 and IFN-γ release by T helper cells according to their phenotype via H₂-receptors. This study extends the immunomodulatory effects of histamine which may contribute to the perpetuation of airway inflammation in asthma.     

Characterization of idiotopes on MOPC 315 IgA using monoclonal antiidiotypic antibodies

The isologous antiidiotypic response in BALB/c mice to immunization with the DNP-binding IgA myeloma protein, MOPC 315, alters the expression of the anti-DNP antibody repertoire and confers immunity against MOPC 315 myeloma tumors. In order to characterize the idiotopes on MOPC 315 IgA which elicit this response we have isolated four monoclonal antiidiotypic antibodies (AIA), D10 (IgG_2a), A2(IgG₁), G3 (IgG_2b) and F1 (IgG_2a), produced by splenocytes of BALB/c mice immunized with MOPC 315 IgA in three independent fusion experiments. These AIA react with MOPC 315 IgA. reassociated H³¹⁵ L³¹⁵ and F³¹⁵_V but not with free H³¹⁵, L³¹⁵, V³¹⁵_H or V³¹⁵₂. In addition the AIA do not react with the closely related DNP-binding IgA myeloma protein, MOPC 460, suggesting that they are directed against private idiotopes on MOPC 315 IgA. These idiotopes can be divided into two groups. Group I, defined by D10, A2 and G3 consists of two overlapping idiotopes, one of which is related to the hapten-binding site. The two idiotopes are formed by an interaction of amino acids in H³¹⁵ and L³¹⁵. Group II defined by F1 consists of one idiotope which is related to the hapten-binding site. This idiotope is comprised of an aminoacid sequence on H³¹⁵ which requires an interaction with either L³¹⁵ or L⁴⁶⁰ for expression. A2 and G3 react identically with the same idiotope but were derived from two independent fusion experiments. This indicates an identity of AIA clonotypes among individual mice and suggests that the isologous AIA response to MOPC 315 IgA is restricted.     

Ependymal changes in experimental hydrocephalus

A morphologic investigation of ependyma over gray matter (caudate nucleus) and over periventricular white matter (tapetum) of the rabbit lateral ventricle was performed four months after the induction of experimental hydrocephalus. Ependymal cells over the caudate nucleus are not modified by hydrocephalus. They remain cuboidal and heavily ciliated. Numerous microvilli cover the cell surface. The extracellular space of the neuropil is not expanded. Ependymal cells over the periventricular white matter are markedly modified. The characteristic response of these ependymal cells is to enlarge and to form lacunae in their apical cytoplasm. Their apical, horizontal cytoplasmic processes elongate as adjacent ependymal cells separate. The ex-tracellular space of the neuropil is expanded. It is proposed that the changes seen in ependymal cells over periventricular white matter are a response to enlargement of the ventricular surface permitted by the orientation of neuronal and glial fibers parallel to the ventricular surface. With expansion of the ventricular surface, overlapping apical processes become elongated and modified, containing a terminal web. With further enlargement, sliding of an overlapping apical process of one cell uncovers the apical process of its neighboring cell. By this mechanism, the ventricular surface area of any ependymal cell whose surface has been partially covered by its neighbor is increased. With further progression, this compensation fails and the neuropil is exposed to the ventricular cavity. Over caudate nucleus, expansion of ventricular surface is hindered by the disposition of fascie adherentes along intercellular clefts oriented perpendicular to the ventricular surface. Lateral sliding of horizontal apical processes does not occur as such processes are not found in ependyma over the caudate nucleus. The differential response of the ventricular surface in these two areas characteristically seen in hydrocephalus is; determined by regional differences in the morphology of their ependymal cells and underlying neuropil.     

The role of size, sequence and haplotype in the stability of FRAXA and FRAXE alleles during transmission

Factors involved in the stability of trinucleotide repeats during transmission were studied in 139 families in which a full mutation, premutation or intermediate allele at either FRAXA or FRAXE was segregating. The transmission of alleles at FRAXA, FRAXE and four microsatellite loci were recorded for all individuals. Instability within the minimal and common ranges (0-40 repeats for FRAXA, 0-30 repeats for FRAXE) was extremely rare; only one example was observed, an increased in size at FRAXA from 29 to 39 repeats. Four FRAXA and three FRAXE alleles in the intermediate range (41-60) repeats for FRAXA, 31-60 for FRAXE) were unstably transmitted. Instability was more frequent for FRAXA intermediate alleles that had a tract of pure CGG greater than 37 although instability only occurred in two of 13 such transmissions: the changes observed were limited to only one or two repeats. Premutation FRAXA alleles over 100 repeats expanded to a full mutation during female transmission in 100% of cases, in agreement with other published series. There was no clear correlation between haplotype and probability of expansion of FRAXA premutations. Instability at FRAXA or FRAXE was more often observed in conjunction with a second instability at an independent locus suggesting genomic instability as a possible mechanism by which at least some FRAXA and FRAXE mutations arise.      

Case management

Providing cost-effective high quality healthcare services ranks as the number one concern for anyone involved with the healthcare delivery system. While quality of care should always be the number one priority, controlling healthcare costs receives most of the attention. With limited healthcare dollars and providers assuming more of the financial risk for services rendered, a whole assortment of cost-containment strategies are being introduced in an effort to maintain some semblance of financial viability. Healthcare providers can approach cost control from two different angles. On the fixed-cost operational overhead side, traditional cost-containment techniques have focused on downsizing, maximizing productivity, staffing redesign, improved purchasing contracts, standardization, inventory control, and other more individualized restructured service models. On the variable-cost clinical side, cost control has been approached by introducing a variety of cost-containment strategies designed to improve efficiency and effectiveness of provider performance. While many of these strategies, previously discussed in the Journal of Healthcare Resource Management have stressed the importance of education, guidelines, pathways, and other clinical "tools for improvement," the success of many of these tools resides in the ability to provide real-time intervention. Real-time intervention rather than the more passive retrospective variance analysis has the greatest potential for producing cost savings by actually making a recommendation that prevents the unwanted event from occurring. In many institutions, the case manager bears the responsibility for monitoring and managing these programs. This article describes various case management models currently used by different institutions.     

Urethral duplication in the male: review of 16 cases

PURPOSE: Urethral duplication is a rare congenital anomaly. The clinical presentation varies because of the different anatomical patterns of this abnormality. We describe our experience with 16 male patients with this anomaly. MATERIALS AND METHODS: We retrospectively reviewed the records of 16 male patients treated for urethral duplication in the last 10 years. Age at presentation ranged from newborn to 8 years. Evaluation included ultrasound, voiding cystourethrography, retrograde urethrography and endoscopy. RESULTS: A blind ending duplicated urethra (type I) was present in 4 patients, 2 independent urethras with distinct bladder necks (type IIA1) in 6, 2 urethras originating from a common bladder neck (type IIA2) in 4, and complete urethral and bladder duplication (type III) in 2. Six patients had associated vesicoureteral reflux. Duplication was an incidental finding at epispadias repair in 3 patients with bladder exstrophy, at hypospadias repair in 1 and at hydrocele repair in 1. One patient with bilateral dysplastic kidneys died in the newborn period. Surgical management included excision of the duplicated urethra in 8 cases and urethroplasty using a pedicle flap in 2, while surgical management was not required in 3. CONCLUSIONS: Urethral duplication is a rare congenital anomaly with a variable clinical presentation. This pathological condition may easily be under diagnosed, especially in patients with other associated anomalies, such as hypospadias or bladder exstrophy. Surgical management should be planned individually according to the anatomical findings of the abnormality.     

A monoclonal antibody directed against a granule membrane glycoprotein (GMP-140/PADGEM, P-selectin, CD62P) inhibits ristocetin-induced platelet aggregation

P-selectin (also called CD62, GMP-140, PADGEM, CD62P) is a recently described member of a family of vascular adhesion receptors expressed by activated platelets and endothelial cells that are involved in leucocyte cell adhesion. The aim of this study was to characterize a new monoclonal antibody (LYP7) directed against activated human blood platelets that inhibits ristocetin-induced platelet aggregation. Immunoadsorbent affinity chromatography and immunoprecipitation studies showed that LYP7 (IgG₁) bound a surface-labelled glycoprotein (GP) which changed its apparent molecular mass (M_r) on reduction from 138 kD (situated below GPIIb) to 148 kD (above GPIIbα). LYP7 and S12, a monoclonal antibody directed against P-selectin immunoprecipitated the same band. Using ELISA assay, purified P-selectin was shown to bind LYP7 and S12 monoclonal antibodies. Binding sites of ¹²⁵I-labelled LYP7, which was greatly increased on thrombin-stimulated (2 U/ml) washed platelets (10825±2886, mean ±SD) (K_d=1.5±0.5 nm ) compared to resting platelets (2801±1278, mean ±SD) (K_d=1.5±0.6 nm ), was found to be normal on thrombin-stimulated platelets taken from a patient with grey platelet syndrome or a patient with Glanzmann thrombasthenia. LYP7 (IgG₁, F(ab′)₂ or Fab fragments) inhibited ristocetin-induced platelet aggregation of platelets in a dose-dependent fashion without affecting the binding of von Willebrand (vWf ) factor. However, agglutination of formaldehyde-fixed platelets induced by ristocetin was not affected by monoclonal antibody LYP7. In addition, the binding of thrombin-activated platelets to neutrophils was inhibited by monoclonal antibody LYP7. These results strongly suggest that P-selectin, by promoting cell–cell contact, may play an active role in platelet–platelet interactions.     

Physiological concentrations of melatonin inhibit the nitridergic pathway in the Syrian hamster retina

In the present work, the effect of melatonin on the hamster retinal nitridergic pathway was examined. When the retinas were incubated in the presence of low concentrations (1 pM-10 nM) of melatonin for 15 min, a significant decrease of nitric oxide synthase (NOS) activity was observed. However, when crude retinal homogenates were preincubated with melatonin for 15 min, no changes in NOS activity were detected, despite the fact that under the same conditions trifluoperazine, a calmodulin inhibitor, significantly decreased enzymatic activity. Kinetic analysis showed that melatonin decreased the V(max) of retinal NOS without changes in the K(m). On the other hand, low concentrations (100 pM) of melatonin significantly reduced retinal L-arginine influx. A decrease in the V(max) of L-arginine uptake was observed in the presence of melatonin, whereas the K(m) remained unchanged. Melatonin significantly inhibited the accumulation of cyclic guanosine monophosphate (cGMP) levels induced by both L-arginine and sodium nitroprusside (SNP). In summary, the present results indicate that melatonin could be a potent inhibitor of the retinal nitridergic pathway.     

Serotonin release mechanisms in bovine pineal gland: stimulation by norepinephrine and dopamine

An assessment of serotonin (5HT) release was made in bovine pineal gland. Bovine pineal fragments took up [3H]5HT by a Na+-dependent process exhibiting two apparent Km, i.e. a high affinity uptake system (Km = 220 nM) and a low affinity uptake system (Km = 197 microM). A significant release of [3H]5HT was elicited by increasing K+ concentrations in the medium (20-80 mM). Exposure of bovine pineal fragments to varying doses of catecholaminergic agonists indicated that a significant [3H]5HT release was elicited at the following threshold concentrations: 10(-6) M norepinephrine (NE), 10(-7) M dopamine (DA), 10(-6) phenylephrine and 10(-6) M isoproterenol. By employing specific receptor agonists and antagonists, the 5HT release activity of adrenergic agonists was found to be mediated by alpha 1-adrenoceptors, while that of DA by D2-dopaminergic receptors. 5HT release elicited by NE or DA, as well as that by 30 mM K+, was Ca2+-dependent. Both NE and DA increase 45Ca2+ uptake in a dispersed cell preparation of bovine pineal glands. As in the case of 5HT release, the effect of NE and DA on calcium uptake was mediated by alpha 1-adrenoceptors and D2-dopaminergic receptors, respectively. These results indicate that both NE and DA control 5HT release in bovine pineal gland.