Effects of melatonin and 6-methoxy-tetrahydro-beta-carboline in light induced retinal damage: a computerized morphometric method.

The effects of melatonin and a related 5-methoxy-indole, 6-methoxy-1,2,3,4-tetrahydro-beta-carboline (6-MeO-THBC) were investigated in rats on the development of retinal degeneration in presence of high intensity illumination (HII). A morphometric method is used in which the degree of degeneration was evaluated by a computer-coupled graphical analyzer. Instead of measuring individual thicknesses of different retinal layers at various loci we measured large areas of retinal light microscopic sections. Thus the influence of sporadic artefactual and other fluctuations in the thickness of various layers of the retina can be essentially reduced. Continuous light produced significant degeneration of the retina and the degree of degeneration was further increased by both studied compounds and even more by 6-MeO-THBC. The role of melatonin and 6-MeO-THBC in retinal physiology is discussed.

Effects of airpolishing on dental plaque removal and hard tissues as evaluated by scanning electron microscopy.

The effect of an air-powder abrasive system on dental hard tissues was tested on 20 volunteers. Impressions of 150 randomly selected areas were taken before and after airpolishing and positive replicas were prepared for scanning electron microscopic examination (SEM). The amount of dental plaque on tooth surfaces was reduced by the treatment (P less than 0.001). The abrasive changes caused by airpolishing on enamel were greater on the surfaces covered by dental plaque before the airpolishing compared to the surfaces without plaque (P less than 0.01). The enamel and cemental surfaces were more abraded after the treatment compared with the initial condition. Despite the effectiveness of the dental airpolishing technique, the negative aspects should be considered in the decision to use airpolishing in routine prophylaxis, especially in patients with root surfaces exposed to the oral cavity.

The gingival effects of dental airpolishing as evaluated by scanning electron microscopy.

An air-powder abrasive system was tested among 20 volunteers, who had healthy gingiva or slight gingivitis, but no periodontal pockets. Impressions of randomly selected areas (n = 103) were taken before and after airpolishing and positive replicas were prepared for scanning electron microscopy (SEM). Gingival bleeding increased statistically significantly (p less than 0.001) during the treatment. Also gingival erosive changes were increased when using airpolishing technique (p less than 0.001). The erosive changes observed by SEM and the subjective symptoms during and after the operation positively correlated to the presence of gingival inflammation (p less than 0.001). It can be concluded that also the negative aspects of the airpolishing technique should be taken into consideration, especially when operating near the gingival margin.

Free amino acid levels in oral fluids of normal subjects and patients with periodontal disease.

The content of free amino acids in submandibular, parotid and whole saliva and in gingival fluid was measured by automatic analyser in patients with progressive periodontitis and in controls. The concentration of individual amino acids showed considerable variation in all the fluids. Two amino acids, proline and delta-aminovaleric acid, were never found in gingival fluid or in submandibular and parotid saliva, although detectable in whole saliva. Thus, these amino acids must appear in whole saliva as a result of bacterial metabolism or by degradation of salivary proteins rich in proline. The free amino acid levels in whole saliva did not reflect those of any of the single oral fluids analysed, further stressing the importance of bacterial metabolism as a cause of the wide range of amino acid concentrations. Because of the multifactorial origin of these free amino acids, their determination in oral fluids is of no practical diagnostic value except perhaps in extreme cases.

Internalization of receptor-bound human chorionic gonadotrophin in preovulatory rat granulosa cells in vivo.

The subcellular distribution of 125I-labelled human chorionic gonadotrophin (hCG) in preovulatory rat granulosa cells was studied in vivo. Pregnant mare serum gonadotrophin-pretreated immature female rats received an iv injection of [125I]hCG a few hours before the endogenous preovulatory gonadotrophin surge. The animals were killed at 2 or 6 h after the [125I]hCG injections. Light microscope autoradiographs showed that the mural granulosa cells of large follicles were the most highly labelled cells in the ovaries. Electron microscope autoradiography was used to study the subcellular distribution of radioactivity in the mural granulosa cells. At 2 h 45% of the counted silver grains were associated with the plasma membrane and 10% with the lysosomes, at 6 h the values were 51% and 9%, respectively. The distribution of the observed silver grains was compared with the generated expected source to grain pairs by computerized linear multiple regression analysis. The magnitudes of the regression coefficients revealed that the plasma membrane and the lysosomes were the only specifically 125I-labelled organelles, that a few radioactive molecules were located diffusely over the cytoplasm at 2 h and that the 125I-radioactivity of the nuclei was negligible. The present results suggest that preovulatory rat granulosa cells are in vivo able to internalize into lysosomes [125I]hCG initially bound to LH/hCG receptors of the plasma membrane.

Effect of radioiodination on the structural integrity, receptor and antibody-binding activity and circulatory behavior of human choriogonadotropin.

Human choriogonadotropin (hCG) was labelled with 125I using a low temperature (4 degrees C), minimal chloramine-T (10 micrograms) concentration and 20-sec oxidization. The structural integrity of labelled hCG was analyzed immediately after the labelling as well as after storage for 7 and 14 days at 4 or -15 degrees C by gel filtration on a Sepharose 6B and Sephadex G-200 column and by polyacrylamide gel electrophoresis. Gel filtrations of freshly labelled hCG revealed a single radioactive peak (Kav = 0.52 and 0.33) corresponding to the intact unlabelled hCG. Polyacrylamide gel electrophoresis also showed a high homogenity of labelled hormone. The capability of freshly labelled hCG to bind to LH(hCG) receptor was 51% and to anti-hCG gamma-globulin Sepharose 4B, 94%. Storage for 14 days at 4 degrees C caused a complete change of the molecule to a smaller conformation (Kav = 0.62 and 0.41) accompanied by a marked reduction in the binding to LH(hCG) receptor (12%). The binding to specific antibody remained high (75%). No change in the structure was found when the labelled hormone was stored for 14 days at -15 degrees C. The hormones also exhibited high binding to the LH(hCG) receptor (45%) and to specific antibody (86%). SDS-polyacrylamide gel electrophoresis indicated that over 90% of the radioiodine present in labelled hCG was associated with the alpha-subunit. No difference was found in the disappearance rate of freshly labelled and fresh unlabelled hCG from the circulation of the rat after a single intravenous injection. The rate of disappearance of the structurally changed hormone was, however, markedly increased and was found to be due to the higher uptake of the hormone by the kidneys and liver. The present observations indicate that hCG retains well its structural integrity and capability to bind to LH(hCG) receptor and specific antibody when radioiodinated with the chloramine-T method. However, there occurs a rapid structural change in labelled hormone molecules under storage at 4 degrees C leading to a smaller conformation, a marked reduction in its binding capability to LH(hCG) receptor and altered metabolic clearance in the rat.

Gingival fluid, beta 2-microglobulin and protein levels as indicators of periodontal disease.

beta 2-microglobulin (beta 2-m), lysozyme and protein concentrations in gingival fluid were analyzed in 19 patients with severe periodontitis and in 19 controls devoid of any clinical signs of inflammation. A significant increase of the total protein and beta 2-m levels was found in periodontal subjects. In contrast, lysozyme concentration did not reflect the inflammatory status of the periodontium. Statistical analyses showed significant correlations between beta 2-m and protein concentrations in both groups. Furthermore, the values obtained by Periotron 600 closely correlated with the protein and beta 2-m contents, indicating that this method is a reliable aid in assessment of the quantity and quality of crevicular exudate and thus the severity of periodontal disease.

Light microscopic autoradiography of rat retinae after intravitreal injection of [3H]6-methoxy-tetrahydro-beta-carboline.

Many beta-carbolines have recently been shown to occur in the human body and animals. beta-carbolines may act as neuromodulators although their physiological role is not known. We have studied the autoradiographic retinal distribution of intravitreally injected [3H]6-methoxy-tetrahydro-beta-carboline (6-MeO-THBC) in rats. The synaptic and ganglion cell layers accumulate pronounced radioactivity, as do some intra- and extracellular locations in the inner nuclear layer and the outer segments of the photoreceptors. The pigment epithelium gradually accumulates a very dense band of radioactivity. 6-MeO-THBC (pinoline, 5-methoxytryptoline, 6-methoxy-1,2,3,4-tetrahydronorharmane) has been shown to possess many important biochemical and pharmacological properties. It has been demonstrated to occur as a normal constituent in the retina of some animals. The relationship between 6-MeO-THBC, melatonin and other 5-methoxy-indoles is discussed.

Assessment of labial salivary gland changes in patients with rheumatoid arthritis by subjective and quantitative methods.

Biopsy of the minor salivary glands is an accepted method in the diagnosis of Sjögren's syndrome, the most characteristic feature being the prominent inflammatory cell infiltration. However, difficulties exist in the early diagnosis of Sjögren's syndrome. The present study was conducted to analyse by subjective and quantitative methods the morphological changes of the salivary glands in patients with rheumatoid arthritis (RA) frequently complicated by Sjögren's syndrome. The subjects of this study were 71 RA patients (mean age 54 +/- 15 years) and their 45 healthy age-matched controls (mean age 60 +/- 14 years). The histologic parameters evaluated were: inflammatory cell infiltration; acinar atrophy; fibrosis, and fatty infiltration. Statistically significant differences between the RA and the control groups were found in all parameters (p less than 0.001) except the fatty infiltration. This indicates that destruction of the salivary glands including fibrosis and acinar atrophy is associated with RA. Only the fatty infiltration seems to be an age-dependent change. All salivary gland biopsies of the RA patients were photographed and evaluated planimetrically, for the same parameters as in the subjective evaluation. An excellent reproducibility between the two methods was found, thus indicating the applicability of the subjective evaluation in the assessment of early salivary gland changes in RA patients.

Quantitation of autoradiographic grains in different zones of articular cartilage with image analyzer.

A novel method is introduced for the estimation of grain numbers in autoradiographic sections of articular cartilage with an image analyzer. It is based on separation of grains from the underlying structures by gray level thresholding and determination of the percentage of total area occupied by grains in a relatively large measuring field. The mean grain size is used as a reference to calculate grain numbers per cell profile and per unit area of tissue in various zones of bovine articular cartilage labelled with 35S-sulphate in tissue culture. The results demonstrate considerable zonal differences as well as site related topographic variation in the rate of 35S-sulphate incorporation. The largest site-related variation in the grain counts was observed in the superficial zone, suggesting a delicate control of proteoglycan synthesis in this zone.