Buffer effect, secretion rate, pH and electrolytes of stimulated whole saliva in relation to the renin-aldosterone system.

The aim of this investigation was to study the relationship between the activity of the renin-aldosterone system and the buffer effect, secretion rate and electrolyte concentration of stimulated saliva in healthy subjects. Based on the results of previous salivary tests, 10 subjects with "low" (group A) and 10 subjects with "high" (group B) buffer effect and secretion rate of stimulated whole saliva were studied. Samples of stimulated whole saliva, blood and urine were collected on three occasions with one week intervals. For saliva, buffer effect, secretion rate, pH, Na+ and K+ concentrations, and Na+/K+ ratio were determined as were plasma renin activity (PRA), plasma concentration of aldosterone, and concentration of Na+ and K+ in serum, and Na+, K+ and creatinine in urine. The daily sodium and potassium intake was also calculated but did not differ between the groups. With the exception of K+ concentration, which was significantly higher, all salivary values of group A were significantly lower. In group A there was a relationship between PRA and plasma concentration of aldosterone, on the one hand, and buffer effect, secretion rate, and salivary K+ concentration, on the other. This relationship could not be demonstrated in group B. A possible explanation is that the higher secretion rate of the latter group obscured the effect of the renin-aldosterone system.

Secretion rate and buffer effect of resting and stimulated whole saliva as a function of age and sex.

Duplicate determinations of secretion rate and buffer effect of resting and stimulated whole saliva were made in 629 adults (286 males and 343 females) within an interval of 1-2 weeks. The subjects were arbitrarily classified into four separate age-groups. For all variables studied, a highly significant correlation was obtained between the duplicate tests. The secretion rate of resting as well as stimulated saliva was significantly lower for females than for males. For females, the resting secretion rate was negatively correlated with age. The buffer effect was also significantly lower in the females for both resting and stimulated saliva. For the females, the buffer effect was positively correlated with age and therefore, with advancing age, the females tended to catch up with the males. Irrespective of sex, the secretion rate of resting saliva was highly correlated to that of stimulated saliva. This relationship was established also for the buffer effect. However, between secretion rate and buffer effect a correlation was observed only for stimulated saliva.

Secretion rate and buffer effect of resting and stimulated whole saliva in relation to general health.

The aim of this investigation was to study the possible relationship between general health and the salivary secretion rate and buffer effect. Based on the results of duplicate salivary tests, 92 consecutive dental patients with a very low secretion rate and/or buffer effect of resting and/or stimulated whole saliva were referred for a medical examination, which included blood and urine analyses. Various medical findings were made for 39 per cent of these patients. As comparison, the same medical and salivary variables were studied in 50 subjects who participated in medical screening programs. Medical findings were made for 32 per cent of the subjects, of whom only about one fourth had one or more very low salivary values. For both groups, no statistically significant difference was found for any of the variables studied when comparing individuals with and without medical findings. Therefore, the results obtained did not indicate a relationship between impaired health and a very low salivary secretion rate and/or buffer effect of whole saliva.

Adipose tissue and circulating endothelial cell specific molecule-1 in human obesity.

Adipocytes produce the endothelial-cell specific molecule-1 (ESM-1), which inhibits leukocyte adhesion and migration through the endothelium. This study investigates ESM-1 expression and regulation in human adipose tissue. Subcutaneous abdominal adipose tissue was obtained from seventy postmenopausal women. Fourteen women subsequently underwent non-pharmacological weight reduction. In vitro experiments were performed on adipocytes isolated from human mammary adipose tissue. We determined gene expression by TaqMan RT-PCR and measured ESM-1 levels in serum and cell culture medium by ELISA. Mature adipocytes produced ESM-1. ESM-1 gene expression was higher in adipocytes than in preadipocytes. Cortisol inhibited ESM-1 gene expression in preadipocytes. Insulin and cortisol inhibited adipocyte ESM-1 production in adipocytes. This inhibitory effect of insulin was attenuated by insulin resistance, as ESM-1 gene expression in subcutaneous adipose tissue was increased in obese, hyperinsulinemic women. In contrast, ESM-1 serum levels were reduced in obese women and inversely correlated to C-reactive protein levels. Five percent weight loss did not markedly change gene expression. Circulating ESM-1 levels increased significantly, albeit modestly. ESM-1 is actively produced by adipocytes. However, since ESM-1 adipocyte gene expression and circulating plasma levels are not correlated, other sources of ESM-1 may be more important. Circulating ESM-1 levels are reduced in the overweight and obese, consistent with the notion that ESM-1 may play some role in obesity-associated vascular disease.

Secretion rate, buffer effect and number of lactobacilli and Streptococcus mutans of whole saliva of cigarette smokers and nonsmokers.

Secretion rate and buffer effect of resting and stimulated whole saliva, and number of lactobacilli and S. mutans in stimulated whole saliva were determined for 182 subjects, of whom 109 were cigarette smokers. For secretion rate, no difference between smokers and non-smokers was observed. The median buffer effect was significantly lower in smokers. The median numbers of lactobacilli and S. mutans were significantly higher in saliva of smokers. The number of lactobacilli was significantly correlated with number of cigarettes smoked per day. About 40% of the smokers had greater than or equal to 10(6) S. mutans CFU/ml, which was more than twice that of non-smokers. In a complementary study on 20 smokers, the immediate influence of cigarette smoking on secretion rate and buffer effect of stimulated whole saliva was investigated for 1 h after smoking. No significant effect was found.

Short term fasting and lactovegetarian diet does not affect human saliva.

Forty-two adults, visiting a Swedish health home, participated in the investigation, which included a 6-day period of fasting, followed by a 6-day period with a lactovegetarian diet. The results obtained indicated only a minor and mostly not significant influence on secretion rate, buffer effect, concentration of various electrolytes, and number of lactobacilli and S. mutans of whole saliva.

Assessment and evaluation of individual prerequisites for dental education.

Since 2001 the School of Dentistry of Malmo University in Sweden has used an alternative admissions procedure based on results of an investigation supported by the Swedish Council for the Renewal of Undergraduate Education. The investigation concerned possibilities of predicting dental school performance on the basis of an interview, as well as tests of general intelligence, spatial ability, manual dexterity, empathy and social competence. Two groups of incoming students were followed from start to completion of their training. Significant relationships were found between (i) number of course examinations failed and poor results on interviews, as well as low scores on intelligence, spatial ability, and a test of spatial-manual ability, (ii) good results in a pre-clinical course in cavity preparation and high scores on spatial ability, (iii) assessments of high social competence during training and good results on interviews, as well as high scores on empathy and non-verbal intelligence. Dropout from the study programme could not be predicted, possibly due to the varying reasons for it.

Methylation of mercury from dental amalgam and mercuric chloride by oral streptococci in vitro.

The capacity of the oral bacteria Streptococcus mitior, S. mutans and S. sanguis to methylate mercury was investigated in vitro. Mercuric chloride and pulverized dental amalgam in distilled water, respectively, were used as sources of mercury. Methylmercury was found in the bacterial cells of all three tested strains. The results indicate that organic mercury compounds may be formed in the oral cavity.

High glucose concentrations increase endothelial cell permeability via activation of protein kinase C alpha.

Endothelial cell permeability is impaired in diabetes mellitus and may be increased by high extracellular glucose concentrations. High glucose activates protein kinase C (PKC), a family of kinases vital to intracellular signaling. We tested the hypothesis that high glucose concentration activates PKC in endothelial cells and leads to an increase in endothelial cell permeability via distinct PKC isoforms. Porcine aortic endothelial cells were used, and the PKC isoforms alpha, delta, epsilon, zeta, and theta were identified in these cells. Glucose caused a rapid dose-dependent increase in endothelial cell permeability, with an EC50 of 17.5 mmol/L. Phorbol 12-myristate 13-acetate (TPA) induced an increase in permeability very similar to that elicited by glucose. The effect of glucose and TPA was totally reversed by preincubating the cells with the PKC inhibitors staurosporine (10(-8) mol/L) and Goe 6976 (10(-8) mol/L). Downregulation of PKC by preincubation with TPA for 24 hours also abolished the effect of glucose and TPA on endothelial cell permeability. High glucose (20 mmol/L) caused an increase in PKC activity at 2, 10, and 30 minutes. Cell fractionation and Western blot analysis showed a glucose-induced translocation of PKC alpha and PKC epsilon. Confocal microscopy confirmed the translocation and showed an association of PKC alpha and PKC epsilon with nuclear structures and the cell membrane. Specific antisense oligodesoxynucleotides (ODNs) against PKC alpha reduced the expression of the isoform, abolished the effects of glucose on endothelial cell permeability completely, and reduced the TPA effect significantly. In contrast, specific antisense ODNs against PKC epsilon had no effect on glucose-induced permeability and only a minor effect on the TPA-induced increase in permeability. We conclude that an increase in extracellular glucose leads to a rapid dose-dependent increase in endothelial cell permeability via the activiation of PKC and that this effect is mediated by the PKC isoform alpha.