“Inorganic and Organometallic Clusters and Polymers: Syntheses and Applications” Symposium

Conference Reports: This section contains reports on topical conferences. Reports are usually written at the request of the editorial office, but unsolicited contributions are also welcome. Suggestions should be sent to the editorial office of the Macromolecular journals, preferably by E‐mail to macromol@wiley‐vch.de.     

The Glutamatergic Innervation of Oxytocin- and Vasopressin-secreting Neurons in the Rat Supraoptic Nucleus and its Contribution to Lactation-induced Synaptic Plasticity

The present ultrastructural study analysed the distribution of glutamatergic synapses on oxytocin- and vasopressin-secreting neurons in the rat supraoptic nucleus (SON) after post-embedding immunogold labelling for glutamate and GABA, oxytocin or vasopressin. About 20% of SON axo—somatic synapses were enriched in glutamate immunoreactivity, visible over synaptic-like vesicles, mitochondria and synaptic densities. Double labelling for glutamate and GABA showed that putative glutamatergic terminals were distinct from GABAergic terminals. In ultrathin sections stained for glutamate and either oxytocin or vasopressin, the proportion of glutamatergic synapses was similar on oxytocinergic and vasopressinergic somata in virgin rats under basal conditions of peptide release as well as in lactating rats, in which oxytocin secretion is enhanced. Cross-sectional soma areas were significantly increased in lactating rats: oxytocinergic profiles were, on average, ˜40% larger than in virgin rats. However, the incidence of axo—somatic glutamatergic synapses (assessed as mean number of synapses per 100 μm of plasmalemma or proportion of somatic surface apposed to synaptic active zones) did not diminish, indicating that there was a compensatory increase of synapses during lactation. Also, we found an increase in the number of glutamatergic terminals making synaptic contact simultaneously onto two or more oxytocinergic elements in the same plane of section. Our observations therefore indicate that SON oxytocinergic and vasopressinergic neurons are innervated to a similar extent by a relatively large proportion of glutamatergic synapses. They reveal, moreover, that glutamatergic afferents participate in the lactation-induced synaptic plasticity of the oxytocinergic system.     

Biological markers as indicators of exposure and pneumoconiotic risk: Prospective study

This research is designed to evaluate a number of biological markers to estimate harmful exposure on coal miners from different mining regions in France and to relate the outcome to differences in prevalence of coal worker pneumoconiosis (CWP) between these regions. Eight epidemiological groups of active and ex-miners (smokers and non-smokers) have been selected in the French collieries (North, Lorraine and Provence) according to their occupational and pneumoconiotic status. The following biomarkers have been evaluated: cellularity of sputum, elementary analysis of particles in TEM/EDAX, plasma neutral metalloendo peptidase elastase type (NMEP), leucocyte elastase (HLE), fibronectin (FN) and elastin peptides. Pulmonary alveolitis, expressed by sputum cellularity, is different between active workers groups but not related to the general background of pneumoconiosis prevalence in the French collieries. In the plasma parameters, fibronectin, HLE and NMEP significantly increased in all groups of coal mine workers as compared to the control group, except for fibronectin parameter in Lorraine collierie. The degree of increase of these parameters allow us to discriminate the different groups and suggest that plasma FN, HLE and NMEP may be considered as biological markers of chronic inhalation of coal mine dust particles. The decrease of elastin peptides level in the Lorraine group alone suggests a specific alteration of elastin metabolism. These parameters were not related to the development of pneumoconiosis and its degree of severity.     

Myofibroblasts and the progression of diabetic nephropathy

Background. The cellular mediators of progressive renal fibrosis in diabetic nephropathy remain unknown. Myofibroblasts have been implicated in the pathogenesis of experimental and clinical renal fibrosis. Their role in the progression of diabetic nephropathy is the subject of this study.Subjects and methods. We have studied by immunohistochemistry the expression of cytoskeletal proteins associated with the activation of myofibroblasts; &agr;-smooth-muscle actin (&agr;-SMA), vimentin (Vi) and desmin (D), in the kidneys of 25 patients with diabetic nephropathy (5 patients with diabetic nephropathy (5 patients had a superimposed glomerulonephritis). Comparisons were made with normal tissue for three kidneys removed for renal-cell carcinoma. Correlations were studied between clinical and biochemical parameters with the expression renal cytoskeletal proteins. Results. In normal kidneys, cells expressing &agr;-SMA were confined to the vascular media and adventia while immunoreactive Vi was detected in glomerular epithelial cells. In diabetic kidneys, cells expressing &agr;-SMA were detected primarily in the renal interstitium and to a lesser extent in some glomeruli in association with mesangial proliferation. Vimentin immunostain decreased in glomeruli displaying diabetic hyalinosis and sclerosis. By contrast, strong Vi immunoreactivity was noted in atrophic diabetic tubules and to a lesser extent in the interstitium. Desmin was not detected in either normal or diabetic kidneys. Close correlations were observed between the expression of renal cytoskeletal proteins and the progression of renal insufficiency. Interstitial &agr;-SMA proved to be a predictor of progressive diabetic nephropathy (R² for 1/serum Cr slope=0.608, P=0.00001). This predictive parameters; tubular atrophy (R²=0.477, P=0.00004) and interstitial fibrosis (R²=0.28, P=0.001). Conclusion. We have demonstrated in this study the neoexpression of cytoskeletal proteins within diabetic kidneys. This has allowed the identification of new predicting histological markers for the progression of diabetic nephropathy.     

Prostaglandin synthesis by squamous carcinoma cells of head and neck, and its inhibition by non-steroidal anti-inflammatory drugs

The purpose of this study was to determine the nature and amounts of prostaglandins (PGs) produced by squamous carcinoma cells (SCC) and the sensitivity of these cells to non-steroidal anti-inflammatory drugs. SCC of four lines of the tongue and one line of facial epidermis of humans were incubated in phosphate buffer solution with ¹⁴C-arachidonic acid (AA). Radioactive metabolites in aqueous methanol were chromatographed on Sep-Pack CIS cartridges, separated and quantitated by means of TLC, autoradiography, and liquid scintillation counting. The results showed that cyclooxygenase products, PGs, were the major products formed by all cell lines, and PGE₂ was predominant among the PGs detected. Two radioactive bands corresponding to PGF_2α and three unseparated standards of PGA₂, 15-keto-PGE₂, and 13,14-dihydro-15-keto-PGE₂were detected in lesser amounts. Very small amounts of the lipoxygenase products 12-and 15-HETE were found. The concentrations of indomethacin, ibuprofen and aspirin required to inhibit 50% of PGE₂ synthesis (IC₅₀) by SCC lines were .008- .080, .080–6.4 and 32–88 μM, respectively.     

CT-functional diagnostics of the rotatory instability of the upper cervical spine. Part 2. An evaluation on healthy adults and patients with suspected instability

Nine healthy adults and 43 patients with cervical spine injury were examined by using functional (computerized tomography) CT scanning. The ranges of axial rotation at the levels occiput C0-C1, C1-C2, and C2-C3 were measured. A rotation at C0-C1 greater than 8 degrees; at C1-C2, 56 degrees; or a right-left difference C0-C1 greater than 5 degrees and C1-2 greater than 8 degrees indicates hypermobility. A rotation at segment C1-C2 of less than 28 degrees indicates hypomobility. Surgical stabilization of rotatory instability could be considered as a possible therapeutic procedure.     

Transforming growth factor-beta(1) in the kidney and urine of patients with glomerular disease and proteinuria.

BACKGROUND: Transforming growth factor-beta(1) (TGF-beta(1)) is the major fibrogenic growth factor implicated in the pathogenesis of renal scarring. Proteinuria is a poor prognostic feature for various types of glomerular disease and its toxic action may be related to the activation of tubular epithelial cells towards increased production of cytokines and chemoattractant peptides. In this work we studied the site of synthesis and expression profile of TGF-beta(1) in the renal tissue of patients with heavy proteinuria and examined the relation of this expression with the urinary excretion of TGF-beta(1). METHODS: Twenty-five patients with heavy proteinuria (8.4+/-3.0 g/24 h) were included in the study. All patients underwent a diagnostic kidney biopsy and were commenced on immunosuppressive therapy with corticosteroids and cyclosporin. The sites of synthesis and expression profile of TGF-beta(1) mRNA and protein in the kidney were examined by in situ hybridization and immunohistochemistry. Urinary and plasma TGF-beta(1) levels were determined by ELISA before the initiation of treatment and 6 months later and compared with those of normal subjects and of patients with IgA nephropathy and normal urinary protein excretion. RESULTS: The site of synthesis and expression of TGF-beta(1) in the renal tissue of patients with heavy proteinuria was mainly localized within the cytoplasm of tubular epithelial cells. Interstitial expression was also present but glomerular TGF-beta(1) expression was found only in patients with mesangial proliferation. Urinary TGF-beta(1) excretion was significantly higher in nephrotic patients compared with normal subjects and with patients with IgA nephropathy and normal urinary protein excretion (783+/-280 vs 310+/-140 and 375+/-90 ng/24 h, respectively; P<0.01). In patients with remission of proteinuria after immunosuppressive therapy, urinary TGF-beta(1) excretion was significantly reduced (from 749+/-290 to 495+/-130 ng/24 h; P<0.01), while in patients with persistent nephrotic syndrome, it remained elevated. CONCLUSIONS: The localization of TGF-beta(1) mRNA and protein within tubular epithelial cells, along with its increased urinary excretion in patients with nephrotic syndrome, suggest the activation of these cells by filtered protein towards increased TGF-beta(1) production.