Understanding the mechanism by which Gd(III) coiled coils achieve magnetic resonance relaxivity - a study into the water coordination chemistry.

A class of Gd(III) coiled coils achieve high MRI relaxivity, in part due to their slow rotational correlation time. However, extending their length is unable to further enhance performance, as the mechanism by which relaxivity is achieved is dominated by the presence of three inner sphere waters in rapid exchange, through an associative mechanism.

Cinnabarinic acid, an endogenous metabolite of the kynurenine pathway, activates type 4 metabotropic glutamate receptors.

Cinnabarinic acid is an endogenous metabolite of the kynurenine pathway that meets the structural requirements to interact with glutamate receptors. We found that cinnabarinic acid acts as a partial agonist of type 4 metabotropic glutamate (mGlu4) receptors, with no activity at other mGlu receptor subtypes. We also tested the activity of cinnabarinic acid on native mGlu4 receptors by examining 1) the inhibition of cAMP formation in cultured cerebellar granule cells; 2) protection against excitotoxic neuronal death in mixed cultures of cortical cells; and 3) protection against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine toxicity in mice after local infusion into the external globus pallidus. In all these models, cinnabarinic acid behaved similarly to conventional mGlu4 receptor agonists, and, at least in cultured neurons, the action of low concentrations of cinnabarinic acid was largely attenuated by genetic deletion of mGlu4 receptors. However, high concentrations of cinnabarinic acid were still active in the absence of mGlu4 receptors, suggesting that the compound may have off-target effects. Mutagenesis and molecular modeling experiments showed that cinnabarinic acid acts as an orthosteric agonist interacting with residues of the glutamate binding pocket of mGlu4. Accordingly, cinnabarinic acid did not activate truncated mGlu4 receptors lacking the N-terminal Venus-flytrap domain, as opposed to the mGlu4 receptor enhancer, N-phenyl-7-(hydroxyimino)cyclopropa[b]chromen-1a-carboxamide (PHCCC). Finally, we could detect endogenous cinnabarinic acid in brain tissue and peripheral organs by high-performance liquid chromatography-tandem mass spectrometry analysis. Levels increased substantially during inflammation induced by lipopolysaccharide. We conclude that cinnabarinic acid is a novel endogenous orthosteric agonist of mGlu4 receptors endowed with neuroprotective activity.

Diagnosis, genetic characterization and clinical follow up of mitochondrial fatty acid oxidation disorders in the new era of expanded newborn screening: A single centre experience.

INTRODUCTION: Mitochondrial fatty acid oxidation disorders (FAODs) are a heterogeneous group of hereditary autosomal recessive diseases included in newborn screening (NBS) program in Italy. The aim of this study was to analyse FAODs cases, identified either clinically or by NBS,for clinical and genetic characterization and to evaluate a five years' experience of NBS, in the attempt to figure out the complexity of genotype-phenotype correlation and to confirm the clinical impact of NBS in our centre experience. MATERIALS AND METHODS: We analysed FAODs patients diagnosed either by NBS or clinically, followed since February 2014 to April 2019 at the Regional Screening Centre and Inherited Metabolic Diseases Unit of Verona. Diagnosis was confirmed by plasma acylcarnitines, urinary organic acids, enzymatic and genetic testing. For not clear genotypes due to the presence of variants of uncertain significance, in silico predictive tools have been used as well as enzymatic activity assays. Patients underwent clinical, nutritional and biochemical follow up. RESULTS: We diagnosed 30 patients with FAODs. 20 by NBS: 3 CUD, 6 SCADD, 5 MCADD, 4 VLCADD, 2 MADD. Overall incidence of FAODs diagnosed by NBS was 1:4316 newborns. No one reported complications during the follow up period. 10 patients were diagnosed clinically: 2 CUD, 2 CPT2D, 1 VLCADD, 5 MADD. Mean age at diagnosis was 29.3 years. Within this group, complications or symptoms were reported at diagnosis, but not during follow-up. 12 mutations not previously reported in literature were found, all predicted as pathogenic or likely pathogenic. DISCUSSION AND CONCLUSIONS: Our study highlighted the great phenotypic variability and molecular heterogeneity of FAODs and confirmed the importance of a tailored follow up and treatment. Despite the short duration of follow up, early identification by NBS prevented diseases related complications and resulted in normal growth and psycho-motor development as well.

Activation of mGlu2/3 metabotropic glutamate receptors negatively regulates the stimulation of inositol phospholipid hydrolysis mediated by 5-hydroxytryptamine2A serotonin receptors in the frontal cortex of living mice.

The interaction between 5-hydroxytryptamine(2A) (5-HT(2A)) serotonin receptors and metabotropic glutamate (mGlu) 2/3 receptors underlies the antipsychotic activity of mGlu2/3 receptor agonists in experimental animals and humans. The molecular nature of this interaction is only partially known. We here report for the first time that pharmacological activation of mGlu2/3 receptors attenuates the stimulation of polyphosphoinositide (PI) hydrolysis mediated by 5-HT(2A) receptors in the frontal cortex of living mice. Mice were injected intracerebroventricularly with [myo-(3)H]inositol and treated with drugs 1 h after a pretreatment with lithium, which blocks the conversion of inositol monophosphate into free inositol. Systemic injection of the mGlu2/3 receptor agonist (-)-2-oxa-4-aminocyclo[3.1.0]hexane-4,6-dicarboxylic acid (LY379268) inhibited the stimulation of PI hydrolysis induced by the hallucinogenic 5-HT(2A) receptor agonist (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) without affecting the stimulation by mGlu1/5 or muscarinic receptors. The action of LY379268 was prevented by the preferential mGlu2/3 receptor antagonist (2S,1'S,2'S)-2-(9-xanthylmethyl)-2-(2'-carboxycyclopropyl)glycine (LY341495). N-(4'-cyano-biphenyl-3-yl)-N-(3-pyridinylmethyl)-ethanesulfonamide hydrochloride (LY566332), a selective mGlu2 receptor enhancer, also reduced DOI-stimulated PI hydrolysis when combined with subthreshold doses of LY379268. Systemic LY379268 inhibited DOI-stimulated PI hydrolysis in mice lacking either mGlu2 or mGlu3 receptors but was inactive in double mGlu2/mGlu3 receptor knockout mice, suggesting that both mGlu2 and mGlu3 receptors interact with 5-HT(2A) receptors. Surprisingly, contrasting results were obtained in cortical slice preparations, where LY379268 amplified both DOI- and 3,5-dihydroxyphenylglycine-stimulated PI hydrolysis. Amplification was abrogated by the mGlu5 receptor antagonist 2-methyl-6-(phenylethynyl)pyridine, suggesting that experiments in brain slices are biased by an additional component of receptor-stimulated PI hydrolysis. This highlights the importance of in vivo models for the study of the interaction between 5-HT(2A) and mGlu2/3 receptors.

Regulation of group II metabotropic glutamate receptors by G protein-coupled receptor kinases: mGlu2 receptors are resistant to homologous desensitization.

We examined the regulation of mGlu2 and mGlu3 metabotropic glutamate receptor signaling prompted by the emerging role of these receptor subtypes as therapeutic targets for psychiatric disorders, such as anxiety and schizophrenia. In transfected human embryonic kidney 293 cells, G-protein-coupled receptor kinase (GRK) 2 and GRK3 fully desensitized the agonist-dependent inhibition of cAMP formation mediated by mGlu3 receptors. In contrast, GRK2 or other GRKs did not desensitize the cAMP response to mGlu2 receptor activation. Desensitization of mGlu3 receptors by GRK2 required an intact kinase activity, as shown by the use of the kinase-dead mutant GRK2-K220R or the recombinant GRK2 C-terminal domain. Overexpression of beta-arrestin1 also desensitized mGlu3 receptors and did not affect the cAMP signaling mediated by mGlu2 receptors. The difference in the regulation of mGlu2 and mGlu3 receptors was signal-dependent because GRK2 desensitized the activation of the mitogen-activated protein kinase pathway mediated by both mGlu2 and mGlu3 receptors. In vivo studies confirmed the resistance of mGlu2 receptor-mediated cAMP signaling to homologous desensitization. Wild-type, mGlu2(-/-), or mGlu3(-/-) mice were treated intraperitoneally with saline or the mixed mGlu2/3 receptor agonist (-)-2-oxa-4-aminobicyclo[3.1.0]-exhane-4,6-dicarboxylic acid (LY379268; 1 mg/kg) once daily for 7 days. Inhibition of forskolin-stimulated cAMP formation by LY379268 was measured in cortical slices prepared 24 h after the last injection. Agonist pretreatment fully desensitized the cAMP response in wild-type and mGlu2(-/-) mice but had no effect in mGlu3(-/-) mice, in which LY379268 could only activate the mGlu2 receptor. We predict the lack of tolerance when mixed mGlu2/3 receptor agonists or selective mGlu2 enhancers are used continually in patients.

Analysis of human tumor cells for Ia-like antigens with monoclonal antibodies.

Cultured and noncultured human solid tumors were analyzed for expression of Ia-like antigens with the use of two monoclonal antibodies and a rabbit antiserum against human Ia-like antigens. Of 27 tumor cells tested, 3 melanomas bound antibodies [e.g., 21,563 cpm 131I-labeled staphylococcal protein A ([131I]SpA) with monoclonal antibody Q5/6], but 24 others (1 melanoma, 9 neuroblastomas, 1 medulloblastoma, 3 gliomas, 4 sarcomas, 2 colon carcinomas, 2 transitional cell carcinomas of the bladder, 1 teratoma, and 1 squamous cell carcinoma of the lung) did so minimally or not at all (0-427 cpm [131I]SpA with antibody Q5/6. Monoclonal antibody Q5/6 was quantitatively absorbed with homogenates of 32 noncultured tumors to determine if Ia-like antigens were expressed by neoplastic cells in vivo. Ten milligrams (wet wt) each of 5 of 7 noncultured melanomas removed more than 83% (median, 85%) of the antibody. In contrast, 10 mg each of 10 neuroblastomas, 7 carcinomas, 4 sarcomas, and 4 Wilms' tumors removed less than 47% (median, 19%) of the antibody; even 100 mg of these tumors removed less than 68% (median, 44%) of the antibody.

Rosetting of antibody-sensitized tumor cells with anti-immunoglobulin antibody-coated erythrocytes by a new method for detecting antigens on cells.

Tumor cells were treated with rabbit antibody to tumor-associated cell surface antigens and tested with erythrocytes coated with antibody specific for the sensitizing rabbit immunoglobulin. The sensitized tumor cells formed rosettes with the indicator cells. By this method, we confirmed that line 1 and line 10 hepatoma cells (from two tumors independently induced by diethylnitrosamine in strain 2 guinea pigs) bear antigens not present on normal liver cells. We also confirmed that line 1 and line 10 cells bear antigenically different tumor-associated cell surface antigens. This method appears simpler than other serological methods for detecting tumor-associated cell surface antigens on tumor cells. Also, this method may be a general one for detecting and enumerating cells bearing surface antigens.

One antigen may form two precipitin lines and two spurs when tested with two monoclonal antibodies by gel diffusion assays.

A monoclonal antibody reactive with human immunoglobulin (Ig)G4 and a monoclonal antibody reactive with IgG1, IgG2 and IgG4 were tested with an IgG4 myeloma protein by double diffusion in a polyethylene glycol-containing gel. In a three-well Ouchterlony pattern, the IgG4 myeloma protein formed lines of double partial identity (double spur) with the two monoclonal antibodies. The two spurs lengthened and thickened with decreasing concentrations of polyethylene glycol indicating that soluble immune complexes diffused past the precipitin lines and formed the spurs. In a two-well pattern, the myeloma protein formed two lines with mixtures of the two monoclonal antibodies indicating that the immune complexes formed by the two antibodies distributed bimodally in the gel as if two types of complexes were formed. These unpredicted findings indicate that the process of antigen-antibody precipitation in gels needs to be analyzed further by using monoclonal antibodies.

Two monoclonal antibodies to two different epitopes of human growth hormone form a precipitin line when counterdiffused as soluble immune complexes.

We have tested whether soluble immune complexes obtained by mixing human growth hormone (hGH) with one anti-hGH monoclonal antibody (MAb) can form a precipitin line when diffused against another MAb in a polyethylene glycol containing gel. By testing seven anti-hGH MAbs one against the other in this assay, we have found that 10 pairs of MAbs out of the 21 possible combinations formed a line. Apparently, the first MAb formed soluble hGH dimers that were linked by the second MAb into precipitating linear complexes. Since each precipitin line was formed by the cooperative reaction of two MAbs, this sequential reaction of MAbs may be used in methods for the positive selection of MAbs that are suitable for two-site immunoassays.

Clinically stable very low birthweight infants are at risk for recurrent tissue glucose fluctuations even after fully established enteral nutrition.

OBJECTIVE: In previous cases, we have observed occasional hypoglycaemic episodes in preterm infants after initial intensive care. In this prospective study, we determined the frequency and severity of abnormal tissue glucose (TG) in clinically stable preterm infants on full enteral nutrition. METHODS: Preterm infants born at <1000 g (n=23; G1) and birth weight 1000-1500 g (n=18; G2) were studied at a postmenstrual age of 32±2 weeks (G1) and 33±2 weeks (G2). Infants were fed two or three hourly, according to a standard bolus-nutrition protocol, and continuous subcutaneous glucose measurements were performed for 72 h. Normal glucose values were assumed at ≥2.5 mmol/L (45 mg/dL) and ≤8.3 mmol/L (150 mg/dL). Frequency, severity and duration of glucose values beyond normal values were determined. RESULTS: We observed asymptomatic low TG values in 39% of infants in G1 and in 44% in G2. High TG values were detected in 83% in G1 and 61% in G2. Infants in G1 experienced prolonged and more severe low TG episodes, and also more frequent and severe high TG episodes. In G1 and G2, 87% and 67% of the infants, respectively, showed glucose fluctuations characterised by rapid glucose increase followed by a rapid glucose drop after feeds. In more mature infants, glucose fluctuations were less pronounced and less dependent on enteral feeds. CONCLUSIONS: Clinically stable well-developing preterm infants beyond their initial period of intensive care show interstitial glucose instabilities exceeding values as low as 2.5 mmol/L and as high as 8.3 mmol/L. This novel observation may play an important role for the susceptibility of these high-risk infants for the development of the metabolic syndrome. TRIAL REGISTRATION NUMBER: German trial registration number DRKS00004590.

A monoclonal antibody may show cross-reactivities in Ouchterlony assays but not in other assays.

A monoclonal antibody to human IgG was tested with myeloma proteins of the four IgG subclasses. When tested by immunofluorometric assay, enzyme-linked immunosorbent assay, hemagglutination and hemagglutination inhibition assays, the antibody reacted with IgG3 but not with the other three IgG subclasses. When tested by Ouchterlony assays in the presence of polyethylene glycol, the antibody formed lines with all four IgG proteins. The line with IgG3 was sharp and stable, but the lines with the other three IgG subclasses tended to blur with time and with the lower PEG concentrations. These findings show that Ouchterlony assays can reveal cross-reactions of a monoclonal antibody that can be missed by more sensitive assays.

Identifying immunoglobulin isotypes, allotypes and idiotypes by a hemolytic assay in gel.

We developed a hemolytic radial immunodiffusion assay for identifying immunoglobulin (Ig) isotypes, allotypes and idiotypes by using gels containing erythrocytes coated with anti-Ig antibody or erythrocytes coated with Staphylococcal protein A. These indicator cells lysed specifically when treated sequentially with Ig antigen, the appropriate anti-Ig antiserum (developer) and complement. To identify these Ig subpopulations, we used monospecific indicator cells, e.g. erythrocytes coated with antibody specific for an Ig isotype, and developers with broader specificities ('multispecific'), e.g. antiserum to Fab. Alternatively, we used 'multispecific' indicator cells, e.g. erythrocytes coated with antibody to Fab and monospecific developers, e.g. antiserum to Ig idiotype. To identify Ig subpopulations specifically, either the indicator cells or the developer need to be monospecific. When both the indicator cells and the developer were monospecific, e.g. to allotype and to isotype, the specificity was determined by both reagents and ultimately restricted by the reagent with the narrower specificity, that is, reacting with the smallest Ig subpopulation. This sensitive hemolytic assay may be used to quantitate subpopulations of Ig molecules and may be modified into a reverse plaque forming cell assay to count lymphocytes secreting a given Ig class, type, allotype and idiotype.

Rosetting of human T lymphocytes with goat red blood cells: effect of treatment with 2-aminoethylisothiouronium bromide (AET) and comparison with AET treated sheep red blood cells.

In vitro treatment of goat red blood cells (GRBCs) with the sulphydryl compound 2-aminoethylisothiouronium bromide (AET) increases their specific reactivity with human T lymphocytes without affecting the specificity of the reaction. AET-GRBCs bind to only part of T lymphocytes rosetting with AET-sheep red blood cells (SRBCs): the receptors for both types of RBCs are very simular if not identical, but display higher affinity for AET-SRBCs than for AET-GRBCs. Rosetting of T lymphocytes with AET-GRBCs may be useful to enumerate T lymphocyte subsets in patients with abnormality of the immune system and to fractionate T lymphocyte subpopulations.

Serological, functional, and immunochemical characterization of a monoclonal antibody (MoAb Q2/70) to human Ia-like antigens.

Serological and immunochemical studies showed that monoclonal antibody Q2/70 (MoAb Q2/70), produced by the hybridoma technique, is specific for human Ia-like antigens. This antibody recognizes an antigenic determinant which is different from those defining the serologic polymorphism of Ia-like antigens, and is expressed on subsets of human Ia-like molecules and on lymphoid cells from other species. MoAb Q2/70 inhibits unidirectional MLRs* between allogenic human lymphocytes, but not between murine and human lymphocytes. In ADCC* assays. MoAb Q2/70 mediates lysis of cultured human B lymphoid cells RPMI 4098, effected by murine splenocytes. The antibody is suitable to isolate immunologically functional B lymphocytes from human peripheral blood.

Early ontogeny of rheumatoid factor antibodies. Characterization of a murine neonatal hybridoma autoantibody to IgGl in BALB/c mice.

The ontogeny and the function of rheumatoid factors (RF) are poorly understood. Here we describe a stable neonatal hybridoma cell line of BALB/c origin that secretes a RF autoantibody of the IgM class. By a series of in vitro assays we determined that this RF reacts specifically with the murine IgGl heavy chain. It also binds IgG of several mammalian species. By using mutant IgGl molecules, the reactive epitope was mapped to the CH3 domain of the constant region of IgGl. These findings indicate that clones with reactivity to autologous IgGl exist in normal mice at birth.

Absence of effect of chronic angiotensin II type 1 receptor blockade on endogenous kinin concentrations-induced paw edema model in the rat.

The effects of chronic treatment with losartan. an AT1 receptor antagonist, on the tissue content of bradykinin (BK) and des-Arg9-BK and on their pharmacological effects were examined in the carrageenan-induced paw edema model (0.5% solution, 50 microl/paw) in the rat. These effects were compared with those of angiotensin-converting enzyme inhibitors (ACEi). For this purpose, rats were chronically treated with losartan (3, 10 and 30 mg/kg/day) and enalapril or quinapril (1 mg/kg/day). Endogenous BK and des-Arg9-BK tissue contents at the site of local inflammation were measured by highly sensitive and specific enzyme immunoassays. Losartan 3 mg/kg/day for 7, 14 and 28 days had no significant effect on carrageenan-induced paw edema, but both losartan 10 and 30 mg/kg/day for 14 days significantly increased the hindpaw volume by 50% at 3 h and by 59% at 5 h. These effects, similar to those measured for ACEi, were inhibited by icatibant, a B2 kinin receptor antagonist (32.5 nmol/paw), that reduced carrageenan-induced paw edema to the level seen in vehicle-treated rats. In the same model, and contrary to ACEi, losartan 3, 10 and 30 mg/kg/day for 14 days had no significant effect on endogenous BK and des-Arg9-BK levels in the local inflammatory site or on circulating and tissue ACE activities. These results show, at least in that model, that the potentiating effects of losartan on carrageenan-induced paw edema are independent of the concentrations of endogenous kinins.

Clinical and hormonal outcome after two years of triiodothyroacetic acid treatment in a child with thyroid hormone resistance.

We report here a new family with thyroid hormone resistance (RTH), with phenotypic variability among subjects. Particular emphasis is given to the clinical and hormonal outcome after 2 years of triiodothyroacetic acid (TRIAC) treatment in an affected child with peripheral thyrotoxic features (pituitary RTH [PRTH]). The genetic defect was a substitution in position 1642 (C to A) within the exon 10 of thyroid hormone receptor beta1 (TRbeta1) gene, resulting in the codon change P453T. The mutant receptor had a significantly reduced triiodothyronine (T3) binding affinity. Within this family, the child and the mother suffered from hyperthyroidism and were clinically classified as PRTH, while the maternal grandmother was clinically euthyroid, indicating a generalized form of the disease (GRTH). Rapid normalization of heart rate was initially obtained by the association of the cardioselective beta-blocker atenolol with TRIAC. Nevertheless, long-term TRIAC therapy, through its lowering action of serum thyrotropin (TSH) and thyroid hormone levels, maintained a normal heart rate after atenolol discontinuation and normalized the neurological disturbances and the clinical signs in the child, without any apparent side effect. In fact, growth velocity remained unchanged and no alteration of several parameters of thyroid hormone action at the tissue level was observed, whereas soluble interleukin-2 receptor levels improved significantly, confirming the safety and efficacy of long-term TRIAC therapy for PRTH also during childhood. We thus recommend testing the efficacy of TRIAC therapy in all RTH patients presenting with clinical features of hyperthyroidism.

Detection of anti-Saccharomyces cerevisiae antibodies in Crohn's disease: is it a reliable diagnostic and prognostic marker?

BACKGROUND: In the past few years, serologic markers have been proposed in inflammatory bowel disease. Anti-Saccharomyces cerevisiae antibodies showed high specificity for Crohn's disease. A prognostic role for serology has also been hypothesised. AIMS: To evaluate anti-Saccharomyces cerevisiae antibody distribution in an unselected Italian inflammatory bowel disease population. To analyse whether anti-Saccharomyces cerevisiae antibody status (positive/negative) and/or anti-Saccharomyces cerevisiae antibody titres are associated with clinical variables and outcome measures in Crohn's disease patients. PATIENTS AND METHODS: A series of 299 inflammatory bowel disease patients were evaluated; serum samples were taken and a short clinical history was recorded. anti-Saccharomyces cerevisiae antibodies IgG enzyme-linked immunosorbent assay Medilab (Milan, Italy) kit was used in order to determine anti-Saccharomyces cerevisiae antibody status. RESULTS: Sensitivity, specificity and likelihood ratio for positive test in the differential diagnosis of inflammatory bowel disease was 59%, 89%, 8.1, respectively. Clinical variables significantly associated with anti-Saccharomyces cerevisiae antibody status in logistic regression were found to be ileal location (p=0.01) and earlier age at diagnosis (p<0.01). Among ileal Crohn's disease patients, there was a trend in concordance between anti-Saccharomyces cerevisiae antibody titres and higher number of surgical procedures which was not statistically significant applying more complex statistics. CONCLUSIONS: In an Italian inflammatory bowel disease population, anti-Saccharomyces cerevisiae antibodies status showed characteristics similar to those previously reported. Anti-Saccharomyces cerevisiae antibody positivity is associated with ileal involvement and with earlier onset of Crohn's disease.

[Role of Mycoplasma hominis in acute infections of the female genital system]. / Ruolo del mycoplasma hominis nelle infezioni acute dell'apparato genitale femminile.

A study was carried out on the role of mycoplasma hominis in obstetric and gynecological infections, and the paper reports a case report of acute pelvoperitonitis in a woman fitted with an IUD. The important role of early preoperative diagnosis in underlined and the current criteria for correct antibiotic therapy are discussed.

Cutaneous tuberculosis: atypical skin lesions in immunodepressed patients.

We report a case of secondary skin tuberculosis due to endogenous secondary infection in a 27-year-old subject affected by ulcerative colitis. The clinical appearance the lesion was atypical and its classification uncertain. The morphology of the lesion and the fact that the primary tubercular complex, at pulmonary level, was masked by a simultaneous candidiasis infection were probably due to cell-mediated immunodeficiency consequent to the ulcerative colitis and on-going therapy (Salazopyrin and prednisone). Rapid remission of cutaneous and pulmonary lesions was achieved following specific therapy (rifampicin, isoniazid, ethambutol).