Role of smoking in periodontal disease among diabetic patients.

OBJECTIVE: The objective of the study was to analyse the effect of smoking on periodontal disease in diabetic patients. METHODS: One hundred and fifty patients participated in the study Fifty patients with Type 1 diabetes mellitus (DM) and periodontal disease were the first group; 50 patients with Type 2 DM and periodontal disease were the second group, and 50 non-diabetic patients with periodontal disease were the third group. After anamnesis was taken, the variable in the analysis was smoker/non-smoker The status of the oral hygiene and periodontal condition was recorded using Plaque index, Supragingival calculus index, Subgingival calculus index, Gingival index, Periodontal Disease Index and Community Periodontal Index of Treatment Needs, by the periodontologist. RESULTS: Except Gingival index, mean values of all investigated indices were higher in smokers in all investigated groups. CONCLUSION: Periodontal disease is more advanced in diabetic smokers compared to diabetic non-smokers. It can be concluded that smoking negatively affects the course of diabetic periodontal disease and increases the risk of attachment loss. Diabetic smokers are at high risk for poor periodontal prognosis, and they should be included in careful periodontal treatment.

Evaluation of biological debris on endodontic instruments after cleaning and sterilization procedures.

AIM: To examine the presence of biological debris and the level of contamination on reusable endodontic instruments those were subjected to different cleaning methods prior to sterilization. METHODOLOGY: One hundred and eighty endodontic instruments from eighteen dental practices were analysed. These practices used different decontamination protocols for reusable instruments. The presence of organic debris was detected by the use of Van Gieson's stain. Forty-eight new stainless steel hand instruments were used as controls. The samples were examined by light microscopy. RESULTS: Residual biological debris was observed in 96% of the samples. The mean value of maximum biological contamination was 34% in the group in which the instruments were brushed manually and immersed in alcohol, 25% in the group in which commercially available disinfectants were used and 5% in the group in which the instruments were cleaned ultrasonically. There was a statistically significant difference in the mean values with respect to the cleaning protocol applied (P < 0.001). CONCLUSIONS: The methods used to clean endodontic instruments appear to be generally ineffective for the removal of biological debris. The best method was the one that included mechanical, chemical and ultrasonic cleaning of instruments.

The characteristics of nucleobase transport and metabolism by the perfused sheep choroid plexus.

The uptake of nucleobases was investigated across the basolateral membrane of the sheep choroid plexus perfused in situ. The maximal uptake (U(max)) for hypoxanthine and adenine, was 35.51+/-1.50% and 30.71+/-0.49% and for guanine, thymine and uracil was 12.00+/-0.53%, 13.07+/-0.48% and 12.30+/-0.55%, respectively with a negligible backflux, except for that of thymine (35.11+/-5.37% of the U(max)). HPLC analysis revealed that the purine nucleobase hypoxanthine and the pyrimidine nucleobase thymine can pass intact through the choroid plexus and enter the cerebrospinal fluid CSF so the lack of backflux for hypoxanthine was not a result of metabolic trapping in the cell. Competition studies revealed that hypoxanthine, adenine and thymine shared the same transport system, while guanine and uracil were transported by a separate mechanism and that nucleosides can partially share the same transporter. HPLC analysis of sheep CSF collected in vivo revealed only two nucleobases were present adenine and hypoxanthine; with an R(CSF/Plasma) 0.19+/-0.02 and 3.43+/-0.20, respectively. Xanthine and urate, the final products of purine catabolism, could not be detected in the CSF even in trace amounts. These results suggest that the activity of xanthine oxidase in the brain of the sheep is very low so the metabolic degradation of purines is carried out only as far as hypoxanthine which then accumulates in the CSF. In conclusion, the presence of saturable transport systems for nucleobases at the basolateral membrane of the choroidal epithelium was demonstrated, which could be important for the distribution of the salvageable nucleobases, adenine and hypoxanthine in the central nervous system.

The kinetics of tiazofurin uptake by the isolated perfused choroid plexus of the sheep.

Tiazofurin (TZF-beta-D-ribofuronosyl thiazole-4-carboxamide, NSC-286193) is a synthetic nucleoside analog with potent antitumor activity. Isolated choroid plexuses (CP) of sheep were perfused in situ and the uptake of [3H]-tiazofurin was determined in relation to the recovery of [14C]-mannitol by means of the paired indicator dilution technique. The maximal uptake of tiazofurin was 8.29 +/- 0.84% and was shown to be both carrier-mediated, sodium-dependent and inhibited by adenosine which suggests that it uses the carrier for endogenous nucleosides. However, the total tiazofurin uptake into the choroid plexus was negligible (0.93 +/- 1.97%) as a result of a high backflux, indicating that tiazofurin is not trapped within the cells of the CP to any significant degree. The kinetics for the uptake into the CP were more favorable than for its passage across the blood-brain barrier with a Km of 7.71 +/- 1.42 microM, a Vmax of 1.30 +/- 0.05 microM/min/g and a negligible constant of a free diffusion (Kd) which suggests that the CP/CSF route may act as an alternative pathway into the brain.

Effects of recombinant basic fibroblast growth factor, insulin-like growth factor-II and transforming growth factor-beta 1 on dog dental pulp cells in vivo.

The effects of recombinant basic fibroblast growth factor (bFGF), insulin-like growth factor (IGF)-II and transforming growth factor (TGF)-beta 1 on dental pulp cells were investigated by light and transmission electron microscopy after their implantation for 1 and 3 weeks at central sites of mechanically exposed pulps in dog molar and canine teeth. The implants were Millipore filters that have been soaked with solutions containing 100 or 500 ng/ml of bFGF or IGF-II or 100 ng/ml of TGF-beta 1. Control filters were soaked with dog albumin. No changes in cell organization or matrix synthesis were seen after implantation of control filters. Groups of columnar, polarized cells with numerous mitochondria and Golgi elements or elongated cells unassociated with any matrix deposition were demonstrated after 1 or 3 weeks, respectively, in close proximity to the filters that had been soaked with bFGF solution; at a distance from these implants enhanced formation of an osteotypic matrix was seen beneath the exposure site. No particular response was found in close proximity to the filters that had been soaked with IGF-II solution after 1 or 3 weeks implantation but thick zones of osteodentine were found beneath the exposure site and at adjacent circumferential dentine sites. Numerous elongated, polarized cells with long cytoplasmic extensions invading the filter pores were consistently seen after 1 week in close proximity to the filters that had been soaked with TGF-beta 1 solution. After 3 weeks implantation of these filters, deposition of a tubular matrix surrounding the implants was seen in association with the highly elongated odontoblast-like cells, while enhancement of circumferential dentine formation was also found at adjacent peripheral sites. These experiments demonstrate that TGF-beta 1 when implanted for short term periods at central pulp sites exerted dentine-specific effects, inducing differentiation of odontoblast-like cells and stimulating primary odontoblasts. Implantation of bFGF and IGF-II did not result in reparative dentine formation, but did stimulate osteotypical matrix deposition at a distance from the implants.

Endogenous nucleosides in the guinea-pig eye: analysis of transport and metabolites.

This study investigates the transport of endogenous nucleosides and deoxynucleosides from the capillaries of the eye into the aqueous humour and the lens using the in situ vascular eye perfusion technique in the guinea-pig. The transport of [3H] adenosine and [3H] thymidine across the blood-aqueous barrier proved to be very rapid with a volume of distribution after 4 minutes perfusion reaching 11.9+/-3.0% and 9.93+/-1.1%, respectively. However, the transport of [3H] guanosine and [3H] cytidine was slower, with volumes of distribution reaching only 3.38+/-0.58% and 4.8+/-1.41%. The values for the entry of deoxyadenosine and deoxyguanosine were not significantly different from the values obtained for corresponding ribonucleosides (adenosine and guanosine) so that a change in the pentose sugar does not change the affinity of the nucleoside for the transport protein. Perfusion with a low sodium medium inhibited the transport of [3H] adenosine and [3H] thymidine into the aqueous humour. The presence of 800 nM NBTI also caused a decrease in adenosine transport into the aqueous humour, so that the volume of distribution after 2 minutes reached only 3.78+/-1.87%. These findings suggest that the transfer of adenosine across the blood-aqueous barrier has both concentrative and equilibrative components. The presence of 0.1 mM thymidine had no effect on the [3H] adenosine transport, whereas 0.1 mM of adenosine resulted in a marked decrease on the [3H] thymidine transport which suggests that the concentrative nucleotide transport is probably mediated by both cif and cit transport systems. The cellular uptake of nucleosides into the lens was very rapid and the volume of distribution of purine nucleosides was within the range of 30-50% whereas that for thymidine uptake was somewhat lower, reaching 20-30%. HPLC analysis of the eye structures in the guinea-pig showed that lens, vitreous body and the rest of the eye do not contain either free nucleosides or purine bases in detectable quantities, except for xanthine which was detected in aqueous humour at a concentration of 2.51+/-0.51 mM. However, serum of the anaesthetised guinea-pig did not contain xanthine in detectable amount so it seems that the metabolic degradation of the nucleosides in the guinea-pig eye progresses as far as xanthine, which is then accumulated in the aqueous humour.

The characteristics of basolateral nucleoside transport in the perfused sheep choroid plexus and the effect of nitric oxide inhibition on these processes.

The single pass paired dilution technique was used to measure the uptake of nucleosides across the basolateral face of the isolated in situ perfused sheep choroid plexus (CP). The uptake of labelled adenosine and guanosine into the CP was large (approximately 35%) whereas that of thymidine was less (approximately 15%). The addition of 0.5 mM unlabelled adenosine to the perfusate inhibited the uptake of labelled adenosine by 66%, guanosine by 100% and that of thymidine by 50%, whereas the addition of 0.5 mM unlabelled thymidine caused complete self-inhibition. The backflux of adenosine was very small which may indicate a high rate of cellular metabolism or a flux into cerebrospinal fluid (CSF). The addition of 0.5 mM unlabelled adenosine did not alter the backflux of adenosine, but increased that of guanosine and thymidine. The entry of radioactivity derived from adenosine across the apical side of the CP cells into the newly formed CSF was determined as a 'CSF uptake index' relative to [14C]butanol and found to be about 25%; however, HPLC analysis revealed that the majority of this activity was hypoxanthine, and not adenosine. The complete inhibition of nitric oxide synthase caused a significant reduction in adenosine uptake into the CP and an increase in backflux for this molecule. It would appear that the uptake for adenosine by the CP is governed by the rate of cellular metabolism and not by the rate of transport into the cells of the choroid plexus whereas for guanosine and thymidine, transport is of greater importance.

Kinetics and sodium independence of [3H]-tiazofurin blood to brain transport in the guinea pig.

Tiazofurin is a nucleoside analog with potent antitumor activity. The objective of this study was to define the kinetic parameters of tiazofurin transport from blood into the guinea pig brain. The second aim was to define kinetic parameters of tiazofurin transport inhibition by adenosine (Ki and Kda), as well as whether tiazofurin blood-to-brain transport was performed in countertransport with Na+. In order to determine these parameters, the in situ method of perfusion of guinea pig brain was used. Addition of increasing concentrations of unlabelled tiazofurin to perfusing medium (0.05-2.7 mmol/l) caused progressive decrease of [3H]-tiazofurin brain clearance with Km values ranging from 119.57 +/- 40.12 to 150.17 +/- 51.68 x 10(-6) mol/l. Maximal transport capacity ranged from 325.03 +/- 113.93 to 417.50 +/- 151.53 pmol/min/g. Introduction of adenosine into the perfusing medium (0.005-0.2 mmol/l) caused similar but more rapid decrease of [3H]-tiazofurin brain clearance (Ki = 6.36 +/- 3.14 x 10(-6) mol/l for nucleus caudate and 11.74 +/- 4.85 x 10(-6) mol/l for cerebral cortex). Therefore, it seems that transport system for adenosine plays the main role in tiazofurin brain uptake, but another transport mechanism is also involved in this process. Depletion of perfusing medium from sodium ions did not cause significant change in volume of distribution values for [3H]-tiazofurin in guinea pig cerebral cortex.