Periodontal bacteria in adult twins

BACKGROUND: Both environmental and genetic factors are known to influence clinical measures of periodontal disease. The purpose of this study was to determine whether genetic factors similarly influence the presence of specific periodontal bacteria in subgingival plaque. METHODS: Reared-together and reared-apart monozygous (MZ) and dizygous (DZ) adult twins were examined clinically. Demographic and behavioral information was obtained from each subject by questionnaire. Subgingival plaque samples were obtained from the index teeth, and the presence of P. intermedia, P. gingivalis, A. actinomycetemcomitans, E. corrodens, and F. nucleatum was determined using an immunoassay. RESULTS: Microbiological and clinical data were available for 169 twin pairs. The subject-based prevalences of the bacteria in the twin groups ranged from 11% for Porphyromonas gingivalis to 40% for F. nucleatum. For all species examined, the concordance rates were not significantly different (P > 0.05) between MZ and DZ twin groups. These findings were apparent despite similar smoking histories, self-reported oral hygiene practices, and antibiotic use in the twin groups. Furthermore, MZ twins reared together were not more similar than MZ reared-apart twins with respect to any bacterial species examined. CONCLUSIONS: These findings suggest that in a population with access to routine dental care, any effects that host genes and the early family environment have on the presence of specific bacteria in subgingival plaque are not apparent in adulthood. Most twins with disease in this study had early periodontitis. Results from this study may not necessarily be extrapolated to more advanced disease states.     

Therapeutic touch

In the advanced stages of dementia of the Alzheimer's type (DAT), affected persons present body language and various behaviours expressing discomfort: shouting, agitation, irritability, aggressiveness, tense movements. Nursing, up until now, has had few available means to ease this discomfort. The authors of the following article have conducted an experimental study measuring the alleviating effects of therapeutic touch on the discomfort of persons in the advanced stages of DAT. Experimental group subjects (n = 16) received 5 sessions of therapeutic touch lasting 12.4 minutes. Control group subjects (n = 11) received 5 sessions of simple presence lasting 10.3 minutes. The authors measured subject discomfort levels using the Discomfort Scale for Dementias of the Alzheimer's Type (DS-DAT). Results show that discomfort levels of persons in the advanced stages of DAT decreased significantly after 5 therapeutic touch sessions, becoming significantly lower than levels in the control group. If care was focused on the whole person and his or her comfort, tools like therapeutic touch would become available to nurses, allowing them to enhance the quality of life of the people in their care.     

Centrally acting antihypertensive drugs: Re-emergence of sympathetic inhibition in the treatment of hypertension

Central regulation of the sympathetic nervous system plays an important role in the maintenance of blood pressure. In a subset of patients with essential hypertension, sympathetic activation may contribute to the development and maintenance of hypertension. Unlike the first generation of centrally active antihypertensive drugs, the second generation may be superior because of its selectivity to I1-imidazoline receptor and selective binding to the vasomotor center. Lack of a2 effects differentiates moxonidine from clonidine with respect to monoxidine’s superior side-effect profile (little or no sedation or dry mouth). Clinical trials show that moxonidine is as effective as angiotensin-converting enzyme inhibitors (eg, enalapril and captopril), b-blockers (eg, atenolol), calcium-channel blockers (eg, long-acting nifedipine), and diuretics (eg, hydrochlorothiazide) in lowering blood pressure and that it has superior tolerability. Thus, central modulation of the sympathetic nervous system has re-emerged as an exciting target for blood pressure reduction. Given the multiple adverse effects of sympathetic stimulation in various disease processes, including congestive heart failure, moxonidine may be the next therapeutic option for the management of hypertension and the prevention of target organ dysfunction.     

A limited-sampling strategy for estimation of etoposide pharmacokinetics in cancer patients

Etoposide (VP16), a widely used anticancer drug, is a topoisomerase II inhibitor. A number of studies have highlighted a correlation between hematologic toxicity and pharmacokinetic or physiological parameters. Other studies have also suggested that the anti-tumor response could be related to the plasma etoposide concentration. Therefore, it would seem of interest to individualize VP16 dose regimens on the basis of pharmacokinetic parameters. The aim of this study was to develop and validate a limited-sampling strategy allowing VP16 pharmacokinetic evaluation with minimal disturbance to the patient. A total of 34 patients (54 kinetics) received VP16 at various dose regimens, with doses ranging between 30 and 200 mg and infusion times varying between 0.5 and 2 h. The statistical characteristics of the pharmacokinetic parameters were assessed from the first courses of treatment performed in 23/34 patients; then the following three-sample protocol was designed: the end of the infusion and 5 and 24 h after the start of the infusion. For validation of the model the main pharmacokinetic parameters (clearance, half-lives, volume of distribution) were estimated in the 11 remaining patients by maximum-likelihood estimation (ML) and by Bayesian estimation (BE) using the three sampling times designed. Statistical comparison showed a good concordance between ML and BE estimates (the bias for clearance was –1.72%). The limited-sampling strategy presented herein can thus be used for accurate estimation of VP16 pharmacokinetic parameters. Received: 17 November 1997 / Accepted: 25 August 1998     

Optimal use of L-asparaginase (NSC-109229) in acute lymphocytic leukemia

Between 1971 and 1974, 646 evaluable patients under 20 years of age with previously untreated acute lymphocytic leukemia were treated according to Cancer and Leukemia Group B (formerly Acute Leukemia Group B) Protocol 7111. On a random basis, they received a 10-day course of 1,000 units/kg/day of L-asparaginase before, during, or after a 3-week course of vincristine and corticosteroid. A control group received vincristine and corticosteroid for 4 weeks but no asparaginase. The overall complete remission rate was 85%, which was not altered significantly by any of the induction variables. Patients who received asparaginase for 10 days subsequent to vincristine and corticosteroid had a significantly longer complete remission duration with an estimated median of 45 months, compared to 20 months for the group receiving no asparaginase and 27 months for the other 2 asparaginase regimens. The beneficial effect of asparaginase was noted, irrespective of which 1 of the 2 intensification and maintenance programs the patients received. The 5-year projection indicates a complete remission rate of 50% for those patients receiving subsequent asparaginase as compared to 41% of those induced on other regimens in this study and thus is superior to the use of only vincristine and corticosteroid.