Spatial interactions in simple and combined-feature visual search

To isolate the mechanisms responsible for spatial interactions in visual search, we investigated the effects of inter-element distance and positional jittering in both simple (in/s) and combined-feature (inverted V in Vs) search tasks in which the observer had to find a target in a background of similar nontargets. Thresholds, defined as the stimulus duration for 75% correct, were measured for 'present' and 'absent' target conditions as a function of background numerosity (ranging from 4 to 64 background elements), independently for four inter-element distances and three positional jittering conditions. Results show: (1) both simple and combined-feature search involve a parallel, capacity limited process, (2) thresholds for parallel search of simple features are directly related to inter-element distance whereas this has little effect on thresholds in combined-feature search, and (3) positional jittering has a direct effect on thresholds in combined-feature search and an inverse effect in simple-feature search. These results indicate that two different mechanisms of spatial interactions are involved in parallel search. The activation of each of the two mechanisms depends on the stimulus used. In parallel search for simple and dissimilar features, the underlying mechanism is a short-range one, based on lateral inhibition, whereas the parallel search for combined and similar features is based on a nontarget grouping mechanism which relies on facilitatory interactions between regular elements.

Sigma1 recognition sites in rabbit iris-ciliary body: topical sigma1-site agonists lower intraocular pressure

In this study, we examined the presence of sigma1 and sigma2 sites in the rabbit iris-ciliary body by receptor binding and investigated their effects on intraocular pressure (IOP) in albino rabbits. The iris-ciliary body has binding sites for the sigma1-site agonist [3H](+)-pentazocine (Kd = 4.6 nM; Bmax = 212 fmol/mg protein) and sigma2 sites labeled with [3H]1,3-di-o-tolylguanidine (DTG) (Kd = 8. 2 nM; Bmax = 1120 fmol/mg protein). In competition binding studies, (+)-pentazocine and the sigma antagonist NE-100 displayed high affinity for sigma1 sites (Ki = 2.1 and 2.4 nM, respectively), whereas (+)-N-allylnormetazocine (NANM) was less potent (Ki = 178 nM). Unilateral topical (+)-pentazocine (0.01-0.1%) caused a significant dose-related reduction of IOP in ocular normotensive rabbits and in the alpha-chymotrypsin model of ocular hypertension. (+)-NANM was less potent than (+)-pentazocine. Neither compound altered the IOP of the contralateral eye, and their hypotensive activity was blocked by NE-100 that, by itself, had no effect on IOP. (-)-Pentazocine, (-)-NANM, and DTG had no effect on IOP. DTG prevented the hypotensive effect of (+)-pentazocine, suggesting that it acts as a sigma1-site antagonist. sigma-Site ligands did not affect pupil diameter or cause ocular inflammation. Topical [3H](+)-pentazocine reaches the intraocular tissues within 30 min, and its uptake in the iris-ciliary body and retina was significantly reduced by topical pretreatment with NE-100, as expected for a receptor-specific agent. Reverse-phase HPLC confirmed the presence of intact (+)-pentazocine in iris-ciliary body homogenates. sigma1-Site agonists may offer a novel class of agents potentially effective in the control of ocular hypertension.

Are there differences between the secretion characteristics of NGF and BDNF? Implications for the modulatory role of neurotrophins in activity-dependent neuronal plasticity

In previous experiments the activity-dependent secretion of nerve growth factor (NGF) from native hippocampal slices and from NGF-cDNA transfected hippocampal neurons showed unusual characteristics [Blochl and Thoenen (1995) Eur J Neurosci 7:1220-1228; (1996) Mol Cell Neurosci 7:173-190]. In both hippocampal slices and cultured hippocampal neurons the activity-dependent secretion proved to be independent of extracellular calcium, but dependent on the release of calcium from intracellular stores. Under different experimental conditions, Goodman et al. [(1996) Mol Cell Neurosci 7:222-238] reported that the high potassium-mediated secretion of brain-derived neurotrophic factor (BDNF) from hippocampal cultures was dependent on extracellular calcium. Mowla et al. [(1997) Proc 27th Annu Meet Soc Neurosci New Orleans 875.10] reported on even further-reaching differences between NGF and BDNF secretion, namely, that in hippocampal neurons and in pituitary cell lines NGF was secreted exclusively according to the constitutive pathway, whereas BDNF was exclusively sorted according to the activity-dependent regulated pathway. In view of the crucial importance of such potential differences between the processing, sorting, and secretory mechanisms of different neurotrophins for their modulatory roles in activity-dependent neuronal plasticity, a thorough analysis under comparable experimental conditions was mandatory. We demonstrate that in native hippocampal slices and adenoviral-transduced hippocampal neurons there are no differences between NGF and BDNF with respect to the subcellular distribution and mechanism of secretion; that the activity-dependent secretion of both NGF and BDNF is dependent on intact intracellular calcium stores; and that the differences between our own observations and those of Goodman et al. (ibid.) regarding the dependence on extracellular calcium do not reflect differences between NGF and BDNF sorting and secretion, but reflect the differing experimental conditions used.

Selective cardiodepressant activity of fluodipine, a fluorenone-1,4-dihydropyridine derivative

The effect of the dihydropyridine derivative, 1,4-dihydro-2,6-dimethyl-4-(fluorenon-4-yl)pyridine-3,5-dicarboxyl ic acid diallyl ester (fluodipine) was studied in vitro in different rabbit, rat and guinea pig preparations and in vivo in the rabbit in order to characterize its pharmacological profile at cardiac and at vascular sites. Compared to nifedipine, fluodipine showed a similar cardiodepressant activity, and a much lower inhibitory activity on vascular contraction. The highest tissue selectivity was observed in guinea pig preparations: fluodipine was about 2-3 times more effective than nifedipine on chronotropism and inotropism in isolated atria, and about 150 times less effective on aortic strip contraction. Accordingly, fluodipine (i) showed high-affinity binding to guinea pig ventricular L-type cardiac Ca2+ channels (Ki=2.57 nM), (ii) was about 80 times less effective than nifedipine to inhibit Ca2+ influx in vascular smooth muscle cells and (iii) induced a significant reduction of heart rate in the anesthetized rabbit (ID25=8.5 mg kg(-1), i.v.) without affecting the blood pressure up to 20 mg kg(-1), whereas nifedipine showed a significant hypotensive effect at very low doses (ID25=0.18 mg kg(-1), i.v.). The pacemaker current If of rabbit sino-atrial node myocytes was not affected by fluodipine. These findings demonstrate that fluodipine exerts selective cardiodepressant activity, likely due to a higher affinity for cardiac than for vascular Ca2+ channels.

Regulation of delta opioid receptors by delta9-tetrahydrocannabinol in NG108-15 hybrid cells

In this study we employed the neuroblastoma x glioma NG 108-15 cell line as a model for investigating the effects of long-term activation of cannabinoid receptors on delta opioid receptor desensitization, down-regulation and gene expression. Exposure of NG 108-15 cells to (-)-delta9-tetrahydrocannabinol (delta9-THC) reduced opioid receptor binding, evaluated in intact cells, by approximately 40-45% in cells exposed for 24 h to 50 and 100 nM delta9-THC and by approximately 25% in cells exposed to 10 nM delta9-THC. Lower doses of delta9-THC (0.1 and 1 nM) or a shorter exposure time to the cannabinoid (6 h) were not effective. Down-regulation of 6 opioid receptors was not observed in cells exposed for 24 h to pertussis toxin (PTX) and then treated for 24 h with 100 nM delta9-THC. In cells that were exposed for 24 h to the cannabinoid, the ability of delta9-THC and of the delta opioid receptor agonist [D-Ser2, Leu5, Thr6]enkephalin to inhibit forskolin-stimulated cAMP accumulation was significantly attenuated. Prolonged exposure of NG 108-15 cells to 100 nM delta9-THC produced a significant elevation of steady-state levels of delta opioid receptor mRNA. This effect was not observed in cells pretreated with PTX. The selective cannabinoid receptor antagonist SR 141716A blocked the effects elicited by delta9-THC on delta opioid receptor desensitization, down-regulation and gene expression; thus indicating that these are mediated via activation of cannabinoid receptors. These data demonstrate the existence, in NG 108-15 cells, of a complex cross-talk between the cannabinoid and opioid receptors on prolonged exposure to delta9-THC triggered by changes in signaling through Gi and/or G0-coupled receptors.

Neurotrophin release by neurotrophins: implications for activity-dependent neuronal plasticity

Neurotrophins, secreted in an activity-dependent manner, are thought to be involved in the activity-dependent refinement of synaptic connections. Here we demonstrate that in hippocampal neurons and the rat pheochromocytoma cell line PC12 application of exogenous neurotrophins induces secretion of neurotrophins, an effect that is mediated by the activation of tyrosine kinase neurotrophin receptors (Trks). Like activity-dependent secretion of neurotrophins, neurotrophin-induced neurotrophin secretion requires mobilization of calcium from intracellular stores. Because neurotrophins are likely to be released from both dendrites and axons, neurotrophin-induced neurotrophin release represents a potential positive feedback mechanism, contributing to the reinforcement and stabilization of synaptic connections.

Estrogen regulation of prodynorphin gene expression in the rat adenohypophysis: effect of the antiestrogen tamoxifen

Prodynorphin (Prodyn)-derived peptides are synthesized in a subset of gonadotrope cells and released concomitantly with LH and FSH, and their levels in the rat adenohypophysis are influenced by the gonadal steroid environment. In several hormonal systems, factors that affect peptide levels may modulate the transcription of messenger RNA (mRNA) encoding for the target gene. Therefore, the present study was designed to investigate the effects of gonadal ablation and estrogen replacement on changes in steady state levels of anterior pituitary Prodyn mRNA and on the transcription rate in the adult female rat. The antiestrogen tamoxifen was employed for further exploring the relationships between estrogens and dynorphin (dyn)-related peptides. Adopting a solution hybridization-ribonuclease protection assay, steady state levels of Prodyn mRNA doubled in 2-week ovariectomized (OVX) rats, in parallel with a 3-fold increase in immunoreactive dyn-A-(1-17)-like material (irdyn-A). Estradiol (E2) replacement through sc SILASTIC implants for 1, 3, 7, and 14 days, which produces serum E2 levels between 25-35 pg/ml, restored in a time-dependent manner mRNA and peptide concentrations to values in sham-OVX rats. A significant decrease was observed after 3 days, and after 7 days, the effect was maximal. Tamoxifen (250 micrograms/kg.day, sc) administered simultaneously antagonized the action of E2 on Prodyn gene expression. Tamoxifen administered without E2 for 7 or 14 days significantly raised anterior pituitary levels of Prodyn mRNA and ir-dyn-A. To establish whether E2 and tamoxifen exert their effects on adenohypophyseal Prodyn mRNA by influencing the transcriptional activity of this gene, an in vitro transcriptional elongation assay was performed on nuclei from the anterior pituitary. The transcriptional rate of the Prodyn gene was significantly increased in 2-week OVX rats. Prodyn mRNA synthesis was suppressed in OVX rats exposed to E2, an effect antagonized by tamoxifen administered concomitantly. The antiestrogen administered alone for 14 days further elevated the transcriptional rate of Prodyn mRNA induced by gonadal ablation. In conclusion, E2 down-regulated the synthesis of Prodyn-derived peptides in adenohypophyseal cells. The antiestrogen tamoxifen antagonized the effect of E2 and, when chronically administered to OVX rats, further elevated the postcastrational rise in Prodyn gene expression.

The diagnosis value of beta 2-microglobulin and immunoglobulins in primary Sjögren's syndrome

Salivary and serum concentrations of beta 2-microglobulin, salivary levels of the immunoglobulins, and salivary flow (as measured by a gravimetric method) were assessed in 34 patients and 11 controls. Of the 34 study patients, 16 had a primary form of Sjögren's syndrome (pSS) and 18 had sicca syndrome. The salivary and serum concentrations of beta 2-microglobulin and salivary levels of IgA and IgG were much higher in the patients with pSS than in controls or those with sicca syndrome (p < 0.001). Similarly, the salivary IgM levels of patients with pSS were higher (although at a lower degree of statistical significance) as compared to those of patients with sicca syndrome (p < 0.01) or controls (p < 0.05). No correlation was observed among the salivary flow and the salivary IgG and IgM levels, while there was a negative relationship (p < 0.01 with salivary IgA levels in all 45 patients considered as a whole. In 12 patients with pSS, the coefficient of correlation between the salivary gland biopsy focus score and the salivary (but not serum) concentration of beta 2-microglobulin was highly significant (p < 0.001). A similar relationship was observed with the IgG (p < 0.001) and IgM (p < 0.05) levels, but not IgA. In the diagnosis of pSS, the salivary IgA level demonstrates high sensitivity and low specificity. In contrast, serum and salivary concentrations of beta 2-microglobulin, salivary IgG, and to a lesser degree, salivary IgM have high specificity and positive predictive value.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential effects of modified beta-cyclodextrins on pharmacological activity and bioavailability of 4-biphenylacetic acid in rats after oral administration

Gastric tolerability, absorption and pharmacological activity of the non-steroidal anti-inflammatory drug 4-biphenylacetic acid (BPAA), as an inclusion complex with beta-cyclodextrin (beta-CyD) or chemically modified beta-CyDs: 2,6-di-O-methyl-beta-CyD (DM-beta-CyD), 2,3,6-tri-O-methyl-beta-CyD (TM-beta-CyD) and 2-hydroxypropyl-beta-CyD (HP-beta-CyD), were investigated in the rat after oral administration. BPAA absorption, determined from area under the plasma concentration-time curve (AUC), was increased by complexation with all beta-CyDs in the following order: DM-beta-CyD > TM-beta-CyD > HP-beta-CyD > beta-CyD. The carrageenan paw oedema test demonstrated a significant increase in anti-inflammatory activity of BPAA and the ED50 values, compared with BPAA alone, were reduced to about a third for the BPAA-DM-beta-CyD complex and halved for the others. BPAA complexed with DM-beta-CyD, HP-beta-CyD or beta-CyD showed better gastric tolerability compared with uncomplexed drug, whereas the BPAA-TM-beta-CyD complex produced marked gastric lesions similar in extent to BPAA alone. TM-beta-CyD (500 mg kg-1) and DM-beta-CyD (1000 mg kg-1) caused gastric erosions 21 h after oral administration. The pharmacokinetic profiles of BPAA-beta-CyD complexes have shown that DM-beta-CyD is the most effective in enhancing the bioavailability of BPAA.

Post-transcriptional inhibition of ornithine decarboxylase induction by zinc in a difluoromethylornithine resistant cell line

Addition of Zn2+ to cell medium inhibited the induction of ornithine decarboxylase (ODC) activity in ODC overproducing L1210-DFMOr cells. A significant effect was observed at a concentration as low as 0.01 mM, however, a more marked inhibition was caused by the addition of 0.1 mM Zn2+. The inhibition of the induction of ODC activity was accompanied by a proportional decrease in the content of immunoreactive ODC protein, whereas the level of ODC mRNA, determined by a solution hybridization RNase protection assay, was not affected significantly. Instead, some acceleration of ODC turnover was observed. The addition of 0.1 mM Co2+ or Mn2+, but not of other divalent metal ions, also inhibited ODC induction; differently from Zn2+ however, these metals affected cell viability and/or cell growth. Removal of endogenous Zn2+ by a chelator also provoked a strong decrease of ODC induction, which was reversed by Zn2+. However, addition of Zn2+ in excess of the chelator proved to be markedly inhibitory. These results indicate that both a restricted Zn2+ availability and an enhanced presence of the metal can inhibit the induction of ODC in L1210-DFMOr cells.

Inhibition of proopiomelanocortin expression by an oligodeoxynucleotide complementary to beta-endorphin mRNA

Gene expression in mammalian cells can be suppressed by oligonucleotides complementary to the target mRNA. This strategy was explored as a means of arresting translation of the prohormone precursor proopiomelanocortin (POMC), used as a model system of peptide messengers that are synthesized and released from endocrine and neuronal cells. The synthesis of the POMC-derived peptides adrenocorticotropin (ACTH) and beta-endorphin (beta-END) was markedly reduced by an oligodeoxynucleotide (ODN) complementary to a region of beta-END mRNA in AtT-20 cells, which retain many of the differentiated phenotypes of corticotrophs; this treatment did not affect the steady-state levels of POMC mRNA. Antisense ODN was stable in cell culture medium for 24 h, and cellular uptake was low (approximately 2.5% of the added ODN); however, the intracellular levels of the ODN were sufficient to form a ribonuclease-resistant duplex with complementary cellular mRNA. Addition of ODN to the cell culture did not affect the cellular levels of chromogranin A-(264-314)/pancreastatin or cell viability and proliferation, as evidenced by bromodeoxyuridine incorporation and ornithine decarboxylase activity. Microinfusion of the antisense ODN in the rat hypothalamic arcuate nucleus, where the majority of POMC-positive brain perikarya are located, significantly reduced ACTH- and beta-END-immunopositive neurons, and antisense ODN-treated rats showed substantially less of the grooming behavior usually observed in a novel environment.

Zinc is required for the expression of ornithine decarboxylase in a difluoromethylornithine-resistant cell line

Dilution of quiescent L1210-DFMOr (difluoromethylornithine-resistant) cells in fresh medium containing serum led to the induction of ornithine decarboxylase (ODC) and to the expression of its mRNA, as determined by a sensitive solution-hybridization-RNase-protection assay. Addition of the chelating agent diethylenetriaminepentaacetic acid (DTPA) at seeding time caused an inhibition of the induction of ODC activity by up to 90%, and only Zn2+ of the bivalent metal ions tested was effective in reversing this effect. The inhibition of the induction of ODC activity was accompanied by a marked decrease, prevented by Zn2+ supplementation, of the accumulation of immunoreactive ODC protein and ODC mRNA. DTPA treatment also caused a slight acceleration of ODC turnover. These results indicate that a restricted Zn2+ availability in L1210-DFMOr cells impairs ODC induction remarkably, mainly by affecting the expression of the messenger.

Dynorphin gene expression and release in the myocardial cell

The expression of the prodynorphin gene was investigated in adult cultured rat ventricular cardiac myocytes by using a sensitive solution hybridization RNase protection assay for the quantitative analysis of prodynorphin mRNA. Myocyte culture in high KCl resulted, after 4 h, in a marked increase in cellular prodynorphin mRNA, while a KCl treatment for 6, 12, or 24 h progressively down-regulated the levels of prodynorphin mRNA below the control value. Immunoreactive dynorphin B, a biologically active end product of the precursor, was found to be present in the culture medium in significantly higher amounts than in the cardiac myocytes. The levels of this biologically active K opioid receptor agonist significantly increased after 4 h of KCl treatment and were markedly reduced following a 24-h exposure of the cardiac myocytes to KCl. These KCl-induced effects were all abolished by cell incubation in the presence of the calcium channel blocker verapamil. In single cardiac myocytes, acute stimulation of K opioid receptors with dynorphin B or with the selective agonist U-50,488H increased the level of cytosolic calcium. This effect was abolished by the specific K opioid receptor antagonist (Mr-1452) and was not affected by the removal of calcium from the bathing medium. These results suggest that an opioid gene may influence the myocardial function in an autocrine or paracrine fashion.

Passive immune protection by herpes simplex virus-specific monoclonal antibodies with different plaque development inhibition activity

A series of herpes simplex viruses type 1 (HSV-1) neutralizing monoclonal antibodies (mAbs) with different plaque development inhibition (PDI) activity were tested for passive protection in mice. When virus was inoculated intracranially, mAbs with PDI activity were not more protective than mAbs without PDI activity. However, when virus was inoculated percutaneously, there was a trend indicating that neutralizing mAbs with PDI power were more active in protecting mice from the cutaneous lesion than mAbs without PDI power. The results are discussed in relation to the possible involvement of PDI activity in in vivo protection and to the fact that this mechanism of protection might operate in cutaneous, but not in nervous tissue.

[Salivary immunoglobulins in the diagnosis of primary Sjögren's syndrome]

The salivary concentrations of immunoglobulins and total proteins and the salivary flow rate (measured by the method of Deniker et al.) were determined in 29 patients with keratoconjunctivitis sicca and xerostomia and in 11 healthy subjects. According to Fox criteria the group pf 29 patients was divided into two groups: 14 patients with primary Sjögren's syndrome (pSS) and 15 patients with sicca syndrome (SS). The IgA salivary levels were significantly higher in the patients with pSS than in the patients with SS (p < 0.05) and in the healthy subjects (p < 0.001). Moreover the IgG and IgM salivary levels in the first group of patients were higher than in the group of patients suffering from sicca syndrome (p < 0.05) and in the control group (p < 0.02). The salivary flow rate of the patients with pSS and sicca syndrome was lower when compared with the control group (p < 0.005). No significant correlation was found between the salivary flow rate and the immunoglobulins in the three groups of patients. The salivary flow was inversely correlated (p < 0.01) only with the IgA levels in all 40 subjects. The salivary total proteins were significantly elevated in pSS patients when compared with the SS patients (p < 0.04) and with the control group (p < 0.01). The immunoglobulins/total proteins ratios in saliva were significantly higher in the first group than in the other groups (p < 0.005) for the IgG and in the first group than in the SS patients (p < 0.05) for the IgM; no significant differences were noted for the IgA. The bioptic focus scores, graded according Greenspan's criteria, of minor salivary glands of 20 patients with pSS or sicca syndrome were directly correlated with a high significance (p < 0.001) to IgG salivary levels and with a lower significance (p < 0.05) with IgM salivary levels. No significant correlation was found between the bioptic focus scores and the IgA levels. The present results demonstrated a high specificity (100%) and a good sensitivity (86%) of the assessment of salivary IgG for the diagnosis of pSS. The sensitivity of the salivary levels of IgA was higher than that of IgG (93%) but the specificity was low (50%); on the contrary the specificity of the assessment of salivary IgM was good (92%) but the sensitivity was low (60%). This study therefore indicated that the assessment of salivary IgG has a great value for the diagnosis of pSS because IgG levels are related to the amount of lymphoplasmocytic infiltration.(ABSTRACT TRUNCATED AT 400 WORDS)

Immunoreactive dynorphin A-like material in extracted human hypothalamic-hypophysial plasma

Immunoreactive dynorphin A-like material (ir-dyn A) in human plasma was measured by a validated radioimmunoassay. In peripheral plasma extracts mean concentrations between 20 and 40 fmol/ml were determined in volunteers and in patients with pituitary adenomas. In this latter group superimposable levels were detected three days before and during transsphenoidal microsurgery. Interestingly, ir-dyn A levels evaluated in extracts of hypothalamic-hypophysial plasma obtained during surgery, just after tumor removal, were 4-5 times higher than in peripheral plasma. Reverse-phase high performance liquid chromatography (rp-HPLC) of extracts of peripheral plasma samples revealed two immunoreactive peaks. The major form had the same retention time of dyn A-(1-32); whereas a second, more lipophilic, peak eluted later and was not further characterized. In contrast, rp-HPLC analysis of extracts of plasma collected from the suprapituitary region displayed only one peak eluting in the position of synthetic dyn A-(1-17). The presence of dyn-related peptides in hypothalamic-hypophysial plasma supports the hypothesis that they may play a part in the regulation of hypothalamic and/or pituitary functions in humans.

Effects of Mipragoside on ocular allergic inflammation in the rabbit

We evaluated the pharmacodynamic and pharmacokinetic profile of Mipragoside, a monosialoganglioside isopropyl-ester (as 0.5% w/w ophthalmic gel), on allergic inflammation of the eye induced by reverse passive Arthus reaction, on a non-immune mast cell degranulation elicited by compound 48/80 and on ocular inflammation produced by horse serum. Conjunctiva was sensitized by injection of rabbit antisera to bovine proteins and the allergic conjunctivitis was triggered by intravenous administration of bovine gamma globulin. The permeability of the blood-conjunctival barrier was evaluated by a fluorometric method. Compound 48/80 was topically administered at concentration of 50mg/ml and histological analysis of conjunctiva was performed. Horse serum was administered by intravenous injection at different days. The pharmacokinetic profile of topical 3H-Mipragoside on 48/80 model was investigated and compared with untreated animals. Mipragoside treatment significantly reduced (p < 0.05 vs placebo) the conjunctival vasopermeability induced by reverse passive Arthus reaction as well as successfully reduced the eosinophil levels in the conjunctival epithelium (p < 0.01 vs placebo) elicited by compound 48/80. Further, Mipragoside successfully reduced the primary signs of ocular inflammation produced by horse serum administration. A radiotracer technique was used to evaluate the disposition of 3H-Mipragoside in the rabbit ocular tissues. Disposition of the drug was monitored at 30, 60, 120 and 240 min. 3H-Mipragoside levels in the inflamed conjunctiva were significantly higher (p < 0.01) than in the control eye.

[Salivary and serum beta 2-microglobulin in the diagnosis of primary Sjögren's syndrome]

beta 2-microglobulin (beta 2m) serum and salivary levels and total protein salivary levels were determined in 15 patients with primary Sjögren's syndrome (pSS), 14 patients with sicca syndrome and 11 healthy subjects. beta 2m serum and salivary levels were higher (p < 0.005) in the patients with pSS than in the healthy subjects and in the patients with sicca syndrome. The bioptic focus scores of minor salivary glands were correlated to beta 2m salivary levels with a high significance (p < 0.001) but were not correlated to beta 2m serum levels. The assessment of beta 2m serum and salivary levels is a non-invasive clinical investigation, which may be easily repeated. It is a very sensitive and highly specific test for the diagnosis of pSS. It may be therefore a useful mean to follow the natural course of pSS and to evaluate the effects of therapy.

Dynorphin A-(1–17) and dynorphin B are released from in vitro superfused rat hypothalami. Effects of depolarizing agents and ovariectomy

We measured the release of immunoreactive (ir) dynorphin (dyn) A-(1-17) and dyn B from the rat hypothalamus by an in vitro superfusion technique. The system was validated on the basis of the recovery and stability of radiolabeled peptides added to the superfused hypothalami. These were detected as authentic peptides by reverse-phase high-performance liquid chromatography (rp-HPLC) only in the presence of a cocktail of peptidase inhibitors added to the superfusion medium. We observed spontaneous release of ir-dyn B, evaluated by a validated radioimmunoassay in the superfusates, that was increased by potassium and veratridine depolarization. It was calcium-dependent and tetrodotoxin-sensitive. We could not evaluate ir-dyn A-(1-17) directly in the superfusates, because the peptidase inhibitors added to the medium significantly altered the tracer-antibody reaction. To obviate this problem, pooled superfusate samples were purified on C18 cartridges and assayed by rp-HPLC. Rp-HPLC analysis of superfusates revealed two molecular forms with the same retention time as authentic dyn A-(1-17) and dyn B which were four times higher in K(+)-stimulated fractions. We could not detect dyn A-(1-32), comprising dyn A-(1-17) and dyn B, even though this peptide is recognized by the antibodies used in this study and is detected in acetic acid extracts of the rat hypothalamus. The spontaneous and K(+)-evoked release of ir-dyn A-(1-17) and ir-dyn B were significantly higher in 2-week ovariectomized rats, in parallel with the increase of their content in the anterior hypothalamus preoptic area.

[Serum beta 2-microglobulin and HLA alloantigens in primary Gougerot-Sjögren syndrome. A possible relation with HLA-DR3 specificity]

The relationships between some allo-antigens of the HLA system and beta 2-microglobulin (beta 2m) serum level were examined in a group of 24 subjects with primitive Sjögren's syndrome (pSS). While the beta 2m serum level of all the patients with pSS were higher at the limits of significance (p congruent to 0.05), compared to the values of the 14 control subjects, the division of the patients into two sub-groups of 14 and 10 subjects, according to the presence or absence of the haplotypes DR2 and/or DR3, pointed up a beta 2m serum level which was significantly higher in the first compared to the second (p less than 0.02) and to the group of normal subjects (p less than 0.01). Among the individual haplotypes studied, only the DR3 was observed with a significantly greater frequency (p less than 0.01) in the patients compared to the control group. The haplotype DR3 and also the B8, although at a lesser level, were found to be correlated with a high value of the serum beta 2m: p less than 0.004 and p less than 0.05 respectively. A similar association was not found for the DR2 and DRW52 specificities.