Influence of topical application of chlorhexidine on chronic gingivitis and gingival wound healing in the dog

Abstract— The present study examines the effect of topically applied chlorhexidine gluconate on chronically inflamed gingiva and standardized gingival wounds. Five beagle dogs were fed a soft "gingivitis inducing" diet for a period of 5 months. Subsequently, a 2 % chlorhexidine solution was applied daily for 42 days to the left molars, premolars, and canines of three dogs, the corresponding teeth in the right quadrants serving as controls. The degree of gingivitis, plaque, gingival exudation, and number of crevicular leukocytes were assessed on days 0, 11, 28, 35, and 42. The healing after gingival biopsy was studied in two dogs using the same parameters on days 0, 4, 7, 14, 28, and 42. In one of the dogs chlorhexidine was applied daily to the teeth and gingiva; the other dog had saline treatment. Biopsies for histologic examination were obtained at the beginning and the end of the experiment. From these criteria, it was shown that one daily topical application of 2 % chlorhexidine gluconate to the teeth and gingiva of the dog removes plaque and resolbes a well-established chronic gingivitis. It is concluded that in the dog it is passible through topical applications of chlorhexidine to establish and maintain a plaque- and gingivitis-free dentition.     

Pharmacokinetics of Clofibrate and Chlorophenoxy Isobutyric Acid. I. Cross-over Studies on Human Volunteers

Abstract: The absorption characteristics of five clofibrate preparations were compared in a cross-over study. After a single dose, four capsule preparations containing 500 mg each of oily clofibrate yielded nearly identical serum levels of chlorophenoxy isobutyric acid (CPIB) in the serum. On the contrary, 500 mg of the basic aluminium salt of CPIB given as a tablet gave significantly lower serum levels at each point of time. The excretion of the latter preparation in 24 hrs was only 1/3 of that of the other four preparations. One of the clofibrate preparations and the tablet preparation were compared in a cross-over study lasting five days. 500 mg of both drugs were administered twice daily. The capsule preparation gave steady-state serum levels of 50–65 mg/l of CPIB beginning on the 2nd day. The tablet preparation exhibited a slow rise in the serum levels, and on the 5th day of treatment the differences between the serum levels were no longer significant. The steady-state and elimination kinetics were studied in a 17-day hospital experiment. The plateau levels were 65–80 mg/ml after clofibrate 500 mg twice daily, and 50–60 mg/ml after aluminium chlorophenoxy butyrate, respectively. The daily excretion suggested that the absorption of clofibrate is complete, but that that of CPIB is only 60%. Hence, there was a discrepancy between the absorption and the nearly equal steady-state serum levels. After discontinuing the administration of the aluminium salt, the course of the disappearance of CPIB was first-order, and an elimination half-time of 54 hrs was calculated. On the other hand, after clofibrate, a two-process elimination was seen. The first process had an elimination half-time of about 10 hrs and the second process had one identical to that observed after Al-CPIB or 54 hrs. It is suggested that, after clofibrate, CPIB is found in two pools. The rapidly eliminating pool may mainly represent the drug in plasma, whereas the slowly eliminating pool might represent the take up of the drug in the liver and only slowly released into the circulation. When given as CPIB, some of the compound could be trapped by the liver, and then the rate of elimination would depend on the release from the liver. The slow absorption of CPIB and the delayed gastric emptying after Al⁺⁺⁺ may also contribute to the slow rise in the blood levels. When given as the ester, most of the drug would pass through the liver, and be hydrolyzed in the circulation to give high serum concentrations, and therefore the rate-limiting step of initial elimination would be the renal handling of the drug. Some redistribution is also likely to take place at this initial stage.     

Genetics, genomics and proteomics in atherosclerosis research

Atherosclerosis and its clinical manifestations are the leading cause of death in Western countries. Atherosclerosis is a multifactorial disease characterized by endothelial dysfunction, smooth muscle cell (SMC) proliferation and migration, inflammation, lipid and matrix accumulation and thrombus formation. Multiple genetic and environmental features and interactions between these factors influence the disease process. To understand fundamental pathobiological mechanisms in atherogenesis and to develop and target new therapies, information on genetic factors (atherogenetics), gene expression patterns (atherogenomics) and protein expression patterns (atheroproteomics) are needed. This review will summarize current knowledge in these areas of atherosclerosis research with a special emphasis on microarray technology.     

Time-frequency analysis of spike-wave discharges using a modified wavelet transform

The continuous Morlet wavelet transform was used for the analysis of the time-frequency pattern of spike-wave discharges (SWD) as can be recorded in a genetic animal model of absence epilepsy (rats of the WAG/Rij strain). We developed a new wavelet transform that allows to obtain the time-frequency dynamics of the dominating rhythm during the discharges. SWD were analyzed pre- and post-administration of certain drugs. SWD recorded predrug demonstrate quite uniform time-frequency dynamics of the dominant rhythm. The beginning of the discharge has a short period with the highest frequency value (up to 15 Hz). Then the frequency decreases to 7-9 Hz and frequency modulation occurs during the discharge in this range with a period of 0.5-0.7 s. Specific changes of SWD time-frequency dynamics were found after the administration of psychoactive drugs, addressing different brain mediator and modulator systems. Short multiple SWDs appeared under low (0.5 mg/kg) doses of haloperidol, they are characterized by a fast frequency decrease to 5-6 Hz at the end of every discharge. The frequency of the dominant frequency of SWD was not stable in long lasting SWD after 1.0 mg/kg or more haloperidol: then two periodicities were found. Long lasting SWD seen after the administration of vigabatrin showed a stable frequency of the discharge. The EEG after Ketamin showed a distinct 5 s quasiperiodicity. No clear changes of time-frequency dynamics of SWD were found after perilamine. It can be concluded that the use of the modified Morlet wavelet transform allows to describe significant parameters of the dynamics in the time-frequency domain of the dominant rhythm of SWD that were not previously detected.     

The association of serum oestradiol level, age, and education with cognitive performance in peri- and late postmenopausal women

Objectives

To evaluate whether healthy women show cognitive changes after menopause and whether the possible changes are oestrogen-, age- or education-dependent.

Methods

Forty-eight women, 21 perimenopausal (aged 43–51 years) and 27 late postmenopausal (aged 59–71 years), participated in the study. Verbal and visuomotor functions, visuoconstructive skills, visual and verbal episodic memory as well as attention were evaluated.

Results

Perimenopausal women performed better than postmenopausal women. Serum oestradiol (E₂) level was included in the model in perimenopausal women only given the lack of endogenous oestrogen in postmenopausal women who were also not using hormone therapy (HT). In perimenopausal women, lower E₂ was associated with better visual episodic memory (p < .05), and older age was related to poorer verbal episodic memory (p < .05). In postmenopausal women, more education was associated with better performance in verbal and visuomotor functions, attention as well as verbal episodic memory (p < .05), older age was related to poorer performance in the visuoconstructive test and visual episodic memory (p < .05).

Conclusions

Perimenopausal women had better cognitive performance compared to late postmenopausal women. In perimenopausal women the effect of E₂ was minor. In both groups, age modified cognitive performance, but more so in postmenopausal women. Education did not have any effect on cognitive performance in perimenopausal women, whereas in postmenopausal women education exceeded age as a source of variation. Thus the relevance of education for better cognition was accentuated after menopause.     

Number and timing of antenatal HIV testing: Evidence from a community-based study in Northern Vietnam

Background  

HIV testing for pregnant women is an important component for the success of prevention of mother-to-child transmission of HIV (PMTCT). A lack of antenatal HIV testing results in loss of benefits for HIV-infected mothers and their children. However, the provision of unnecessary repeat tests at a very late stage of pregnancy will reduce the beneficial effects of PMTCT and impose unnecessary costs for the individual woman as well as the health system. This study aims to assess the number and timing of antenatal HIV testing in a low-income setting where PMTCT programmes have been scaled up to reach first level health facilities.     

Serum TLR2 and TLR4 levels in colorectal cancer and their association with systemic inflammatory markers,tumor characteristics,and disease outcome

Toll‐like receptors (TLRs) are involved in colorectal cancer (CRC) pathogenesis. However, the significance of serum TLR concentrations in CRC is unknown. We analyzed serum TLR2 and TLR4 concentrations with ELISA in preoperative samples from 118 patients with CRC and 88 matched controls. We also assessed tissue TLR expression with immunohistochemistry and by detecting serum determinants of systemic inflammation. Most participants (>70%) had undetectable serum TLR2. The mean serum TLR4 levels were lower in patients than in controls (1.1 vs 1.8 ng/mL; p = 0.015). Undetectable TLR4 was more common in stage I (39%) than in stages II–IV (11%, p < 0.001). TLR2 or TLR4 expression in tumor cells did not correlate with serum levels, but abundant TLR2 expression in normal colon epithelium was associated with detectable serum TLR2 (p = 0.034). Undetectable serum TLR2 was linked to high modified Glasgow prognostic scores (p = 0.010), high CRP levels (p = 0.013), blood vessel invasion (p = 0.013), and tended to be associated with worse 5‐year survival (p = 0.052). In conclusion, serum TLR2 levels were inversely associated with systemic inflammation in patients with CRC. Moreover, serum TLR2 levels might depend more on normal colorectal mucosa contributions than on tumor tissue contributions. Further studies are required to assess the prognostic value of serum TLR2.     

Effect of a single dose of TCDD on the level of histamine in discrete nuclei in rat brain

Histaminergic neurones may be involved in the regulation of feed intake. Since TCDD causes anorexia in rats, histamine concentrations were measured in several hypothalamic nuclei involved in feeding regulation. Histamine concentrations were not changed in medial or lateral accumbens, suprachiasmatic, paraventricular, arcuate, ventromedial, dorsomedial or perifornical nuclei, or in lateral hypothalamic area, cortex, or pineal gland. There was, however, an increase in histamine concentration in median eminence 25 h after the administration of TCDD.     

Plasma vasopressin levels after I.C.V. infusion of histamine agonists in the conscious goat

Histamine H₁-agonists 2-pyridylethylamine (2-PEA) and 2-methylhistamine and H₂-agonists 4-methylhistamine, dimaprit and impromidine were given i.c.v. to conscious goats and the release of arginine vasopressin (AVP) was measured. 2-PEA at very low doses (9 and 27 moles/animal, equivalent to H₁-activity of about 0.5 and 1.5 moles histamine, resp.)_significantly increased plasma AVP. The H₂-agonists did not cause consistent changes in AVP even if their relative doses were higher. It is concluded that the vasopressin releasing effect of histamine is due to H₁-receptor activation.