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Biomedical subjects

R G Marks

Publications and source records attributed to R G Marks.

At least 19 recordsLinked to original sources
PubMed1992

Nocturia: a risk factor for falls in the elderly.

OBJECTIVE: To determine if nocturia is a risk factor for reported falls and bone fractures in older persons. DESIGN: Cross-sectional study comparing falls in men and women with and without nocturia. SETTING: Longitudinal health screening program of ambulatory elderly participants. PARTICIPANTS: Participants included 988 (65.5%) women and 520 (34.5%) men who had completed their tenth annual visit to the program. MAIN OUTCOME MEASURES: Reported falls in the past year and reported bone fractures in the past 5 years. RESULTS: Participants who reported nocturia at least twice during the night were at significantly greater risk to report falls (Odds Ratio = 1.84; 95% CI = 1.05-3.22), and the risk increased in subjects reporting more than three nocturia events (Odds Ratio = 2.15; 95% CI = 1.04-4.44). The significant increase in falls reported by nocturia participants did not result in an increase in reported bone fractures in the past 5 years (P < 0.4360). CONCLUSIONS: Nocturia is an important risk factor for falls in ambulatory elderly persons. Preventive measures should be taken to decrease nocturia events and to decrease the risk of falling during these nocturia events.

Accidental Falls↗
PubMed1992

Predictive power of various models for longitudinal attachment level change.

Several statistical models that have been suggested in the periodontal literature for describing longitudinal attachment level changes, such as the gradual loss, single-burst, multiple-burst, and random walk models as well as other models introduced in this paper are compared by their power to predict future attachment loss. The data used in this analysis is from 1061 sites of 8 subjects, with moderate to severe periodontal disease, monitored monthly for about a year. This study found that none of the suggested models could significantly outperform the naïve mean predictor, which predicts the future attachment level from the past mean. It was also found that no single model, such as the burst, gradual, or random walk, together with measurement error can fully explain the variation in the data. These results indicate that in the course of one year, the attachment level change may not follow the same model. Consequently, a model that fits well to past data cannot be accurately extended to the future.

Disease Susceptibility↗
PubMed1992

Reproducibility of an electronic probe in relative attachment level measurements.

4 probing designs have been employed to investigate the reproducibility of the Florida Probe. 3 groups (each composed of 10 subjects) were selected for the study: healthy adults, gingivitis subjects, and periodontitis subjects. The 4 probing designs were as follows: (a) the probe tip was left in the sulcus between successive probings; (b) the probe tip was removed from the gingival margin between probings but the next probing followed immediately; (c) successive whole-mouth probings were interrupted by a 5-min interval and a mouthrinse; (d) there was a 4-week interval between each probing. 3 measurements were taken for each design. The main purpose of this study was to identify variance components in the attachment level variation. The maximum probing error standard deviation was found to be around 0.3 mm, which is considerably smaller than that found in most previous studies. The errors associated with the periodontal condition and probing effect were also estimated. The variance components obtained here can be used for determining the sample size in controlled clinical studies.

Adult↗
PubMed1992

The effect of 3 mouthrinses on plaque and gingivitis development.

The aim of this study was to evaluate the effect of 3 mouthrinses, Listerine Antiseptic (thymol), Peridex (chlorhexidine), Perimed (povidone iodine and hydrogen peroxide), and a placebo (water) on the development of dental plaque and gingivitis, when used as the only oral hygiene procedure for 14 days. 71 subjects were entered into a randomized, double-blind study. At the baseline examination, papillary bleeding score (PBS), and plaque index (PI) were registered, after which subjects received supragingival prophylaxis and were assigned to 1 of 4 study cells. Subjects were asked to refrain from all oral hygiene procedures except for the supervised 14-day 2 x daily rinsing with the assigned preparation. At day 14, the same clinical parameters were again registered. Statistical analysis was performed by a one-way analysis of variance (ANOVA) to compare the 4 groups, followed by Duncan's multiple range test to determine specific group differences. At baseline, average PBS and PI scores were similar for all 4 groups. After 14 days, the average PBS for Peridex and Perimed was significantly lower than for Listerine Antiseptic and water. The frequency of interdental units with a PBS greater than 2 was significantly lower for Peridex and Perimed than for Listerine Antiseptic and water. We concluded that both Peridex and Perimed were effective in reducing plaque and gingivitis when used as a 2 x daily mouthrinse by subjects refraining from other oral hygiene procedures. In vitro, a synergistic effect was assumed when inhibition was achieved with Perimed at the same or greater dilution than was achieved with povidone-iodine alone.

Actinomyces viscosus↗
PubMed1992

A fluoride dose-response evaluation in an anticaries clinical trial.

This study evaluated the dose-response relationship between four increasing levels of fluoride from 1000 to 2500 ppm F as sodium monofluorophosphate (MFP) and three-year dental caries increments, as measured by DMFS, DMFT, and DFS-A on 4424 schoolchildren. The results indicated consistent linear decreases in all three dental indices as the dose level increased to 2500 ppm F MFP, with slopes (average reductions) of 0.32 in DMFS for an increase of 1000 ppm F, 0.13 in DMFT, and 0.17 in DFS-A when all children were evaluated, p less than 0.03 for each index. For children 11 years and older at baseline, the slopes quadrupled, p less than 0.01 for each index. Age and baseline DMFS were shown to be the most important covariates to control for in the statistical models. No differences in adverse reactions, or other safety problems, were observed at the different dose levels.

Acidulated Phosphate Fluoride↗
PubMed1992

Correlates of constipation in an ambulatory elderly population.

Constipation is a common and often perplexing problem for elderly people. The prevalence of self-reported constipation and factors associated with constipation were investigated in 3,166 people over age 65. Twenty-six percent of women and 15.8% of men reported recurrent constipation (p less than 0.0001). There was a significant increase in reported constipation with increasing age (p less than 0.0001). Multiple factors were found to correlate with self-reported constipation. A logistic regression model revealed 13 factors of significance in predicting constipation. The most important factors were age, sex, total number of drugs taken, pain in the abdomen, and hemorrhoids (p less than 0.0001). Specific drugs do not appear to be important factors in constipation in the elderly. Elderly people who report the use of multiple drugs, pain in the abdomen, and hemorrhoids are at increased risk for constipation.

Age Factors↗
PubMed1991

Evaluation of statistical methods for monitoring periodontal disease.

Three methods for detecting the progression of periodontal disease based on the change in attachment level on teeth are compared from a statistical point of view. Regardless of gradual or burst disease progression theories, the regression method is found to be the most efficient way to detect changes. The exact false alarm rate is computed when the decision is based on the maximum regression coefficient at all sites during several visits.

Epithelial Attachment↗
PubMed1991

Effect of psyllium hydrophilic mucilloid on serum cholesterol in the elderly.

The effect of psyllium hydrophilic mucilloid (PHM) when used as a laxative and/or stool softener on serum cholesterol concentrations was examined in 176 ambulatory elderly participants attending a health screening program. The change in one-year serum cholesterol concentration in subjects using PHM was compared with the change in cholesterol in 741 participants who did not report the use of PHM. Serum cholesterol concentration decreased by 0.073 mmol/liter (2.82 mg/dl) in the treatment group compared with a decrease of 0.036 mmol/liter (1.39 mg/dl) in the control group. After adjusting for confounding factors, excluding psyllium dose, by using a multiple regression model there was no significant difference in the change in serum cholesterol concentration (P = 0.935). PHM dosage information was available for 158 participants. After adjusting for baseline serum cholesterol and confounding factors using multiple regression analysis, it was found that the dose of PHM administered was significantly correlated with the change in serum cholesterol (P = 0.0120). For every 1-g increase in daily PHM dose there was a 0.022 mmol/liter (0.84 mg/dl) decrease in serum cholesterol concentration.

Aged↗
PubMed1991

A longitudinal evaluation of drug use in an ambulatory elderly population.

Participants in a geriatric health screening program were studied longitudinally to determine the patterns of drug use over a 10 year period. There were 314 (34.0%) men and 610 (66.0%) women who completed 10 yearly health screening evaluations. The mean number of prescribed and non-prescribed drugs used per participant increased from 2.90 in 1978-79 to 4.08 in 1987-88 (p less than 0.0001). There was no significant difference between men and women in the rate of increased drug use. There was no significant increase in the mean number of drug ingredients per participant used over the 10 year period. The most frequently reported therapeutic categories for 1978-79 were antihypertensives, analgesic-antipyretics, antirheumatics, multiple vitamins, cathartics and vitamin E, which represented 10.2, 7.2, 6.5, 4.9, 4.8 and 3.8% of all categories used. There was a decline in all of these categories between interval 1 and 10. Increased use of drugs, particularly prescribed medications, by the elderly population may present problems of adverse drug reactions, drug interactions and medication compliance in the future. Changing patterns of drug use may have resulted, in part, from introduction of new therapeutic classes and from new treatment concepts over the 10 year study period.

Aged↗
PubMed1991

Progression of visual acuity after penetrating keratoplasty.

A consecutive series of 721 eyes was followed for visual acuity changes after keratoplasty in four groups: keratoconus, Fuchs' dystrophy, pseudophakic bullous keratopathy with retained intraocular lenses, and aphakic/pseudophakic bullous keratopathy with secondary implants during keratoplasty. Follow-up ranged from 12 to 84 months. Keratoconus eyes showed the quickest recovery of visual acuity: by 12 months, 91% attained a best-corrected vision of 20/40, and the mean lines of visual acuity for the group plateaued thereafter. The other three groups showed continuing improvement in vision through 24 months. From 3 months through 3 years after keratoplasty, the keratoconus and Fuchs' groups consistently showed better visual acuity levels than either the retained or the secondary implant groups (P less than 0.0001). Reporting changes in visual acuity over time offers multiple advantages compared with providing best-attained or last-recorded visual acuities after keratoplasty.

Adolescent↗
PubMed1991

Graft survival in four common groups of patients undergoing penetrating keratoplasty.

Graft survival rates and causes of graft failure were evaluated for 1046 consecutive keratoplasties in four groups: keratoconus, Fuchs' dystrophy, pseudophakic bullous keratopathy with retained intraocular lenses (IOLs), and pseudophakic/aphakic bullous keratopathy with secondary lens implants. Patient follow-up averaged 23 months (range, 1-84 months). There was a significant difference in graft survival among the four groups, P less than 0.0001. The keratoconus and Fuchs' groups had the highest survival rates and pseudophakic bullous keratopathy with retained IOLs the lowest rate. Problems with the external surface of the graft caused the largest number of graft failures. Grafts for pseudophakic bullous keratopathy with retained posterior chamber lenses had a significantly higher failure rate from rejection and endothelial decompensation, 5.1%, compared with less than 1.0% in keratoconus, Fuchs' dystrophy, or bullous keratopathy with secondary implants (P less than 0.0005).

Adolescent↗
PubMed1991

Changing patterns of therapeutic agents in the elderly: a ten-year overview.

Drug use patterns in a large ambulatory elderly population were studied cross-sectionally over a 10-year period. There were 24192 drug histories obtained on 4509 individuals during the period from 1 August 1978 to 31 July 1988. The average number of drugs used per person increased from 3.22 in 1978-9 to 3.94 in 1987-8. Prescribed drug use increased by 0.52 per person compared with an increase of 0.21 for nonprescribed medication. Analysis of two mutually exclusive groups of participants from 1978-9 and 1987-8 revealed a significant (p less than 0.0001) increase in the use of nonprescribed medication but no significant increase in the use of prescribed medication after adjusting for age and sex effects. The four most frequently used therapeutic classes of drugs in 1978-9 as a percentage of all drugs used were antihypertensives (10.8%), analgesic-antipyretics (6.4%), antirheumatic (6.4%), and cathartics (5.4%) compared with the antihypertensives (9.5%), analgesic-antipyretics (5.9%), anticoagulants (5.5%), and antirheumatic (4.6%) for the 1987-8 period.

Age Factors↗
PubMed1991

Reproducibility of attachment level measurements with two models of the Florida Probe.

Clinical assessment of the progression of periodontitis is based on the measurement of periodontal probing attachment levels over time. In calculating these changes, duplicate measurements from fixed reference points, including cemento-enamel junctions and acrylic stents, have been used to assist in detecting progressive disease. The Florida Probe has been previously shown to improve the reproducibility of these measurements when used with an acrylic stent. The objective of the present study was to evaluate the reproducibility of 2 models of the Florida Probe, the original stent model and the modified disk model, in measuring attachment level. The disk probe differs from the stent probe in that it uses the occlusal surface of the tooth as a static reference point in calculating changes in attachment level measurements. In 10 subjects, sites were probed 2 x by 2 examiners using both types of probe. Standard deviations and intra- and inter-examiner correlations were calculated. These results demonstrate that the new disk probe yields reproducible measurements similar to the stent probe and is therefore suitable for use in longitudinal clinical studies.

Equipment Design↗
PubMed1991

Clinical, microbiological and immunological characteristics of subjects with "refractory" periodontal disease.

The aim of the present study was to analyze the relationship between attachment loss and clinical, microbiological, and immunological parameters in a group of 21 human subjects exhibiting poor response to previous periodontal therapy. All had been treated with periodontal surgery, tetracycline, and subsequent maintenance recalls to periodontists who, upon detection of disease progression, referred the subjects to our clinic. In our clinic, each subject received oral hygiene instruction and a thorough subgingival scaling and root planing utilizing as many appointments as necessary. Clinical indices, including gingival index, bleeding on probing, suppuration, plaque index, pocket depth, and duplicate measurements of attachment level from an acrylic stent, were collected at monthly intervals. Probing measurements were performed using the Florida Probe. When significant attachment loss (0.8-1.2 mm) was detected in at least 1 site, a bacterial sample was taken from that site and from a comparably deep, but non-progressing, control site. Microbial samples were enumerated by darkfield microscopy, on selective and non-selective media, and by predominant cultivable technique. Blood samples were also collected to determine antibody levels against potential pathogens. There was no difference in the amount of plaque present in sites gaining or losing attachment, but losing sites exhibited more bleeding and suppuration. 20 of the 21 subjects were tested; of these, 17 exhibited elevated serum antibody against one or more of the following microorganisms: Actinobacillus actinomycetemcomitans, Bacteroides, gingivalis, and Eikenella corrodens. However, few, if any, of the "classical" pathogens were detected in the plaque samples obtained at the time progressive disease was diagnosed. The only exception was Streptococcus intermedius, which occurred in slightly higher numbers in active sites.

Actinobacillus↗
PubMed1991

Immune modulation of Prevotella intermedia colonization in squirrel monkeys.

Colonization of the gingival crevice by black-pigmented Porphyromonas or Prevotella spp. (BP/P), including Porphyromonas gingivalis (formerly Bacteroides gingivalis) and Prevotella intermedia (formerly Bacteroides intermedius), is thought to be an important ecological event which may result in the destruction of connective tissues supporting the teeth. Theoretically, periodontal diseases could be prevented if these or other periodontal pathogenic microorganisms did not colonize the subgingival area. The humoral immune response is one mechanism which may modulate bacterial colonization in the gingival crevice. In the present study, we tested the effect of systemic humoral immunity on subgingival colonization by indigenous P. intermedia in squirrel monkeys (Saimiri sciureus). Animals rendered essentially free of detectable BP/P by a single scaling, 10 days of tetracycline therapy, and toothbrushing three times per week were immunized with P. intermedia 1447 or were sham immunized with phosphate-buffered saline. Subsequently, all oral hygiene procedures were discontinued and five teeth in one quadrant were ligated with bacterium-soaked suture material to facilitate BP/P colonization. Immunization resulted in a significant increase in the level of immunoglobulin G anti-P. intermedia antibody in serum. Two weeks after ligation was initiated, P. intermedia could be detected in five of six sham-immunized and three of six immunized animals. Immunization was associated with a reduction in the emergence of indigenous P. intermedia in the gingival crevice.

Animals↗
PubMed1991

Correlates of cognitive dysfunction in an ambulatory elderly population.

Mini-Mental State Examination (MMSE) scores were studied in an ambulatory elderly population to identify correlates with self-reported signs, symptoms, diseases, drugs and laboratory values. A total of 1,264 subjects were studied including 844 women and 420 men. In this study, 5.0% of men and 5.3% of women scored less than 24 on the MMSE. A linear-regression model revealed eleven factors of significance in predicting scores on the MMSE. The most important predictors were age (p less than 0.0001), self-reported memory loss (p less than 0.0001), complaints of swollen feet or ankles (p less than 0.0010), the total number of diseases reported (0.0006) and the serum lactate dehydrogenase concentration (p less than 0.0098). Results suggest that cognitive function in the elderly is not related to the general level of health or consistently affected by specific disease states.

Aged↗
PubMed1991

The effect of supervised brushing on caries inhibition in school age children.

A supervised brushing program was incorporated into a three-year caries clinical trial whose primary objective was to compare the efficacy between two fluoride levels of a dentifrice (1,000 and 1,500 ppm F MFP). For each of the 2,415 children completing the three-year study, the total number of supervised brushing sessions completed was available. Results indicated that children who complied well with the supervised brushing program by participating in at least 70% of the sessions had a significantly lower caries increment in both fluoride levels (p less than .001) than children who did not comply as well. After adjusting for age, sex, and baseline DMFS of the children, as well as the fluoride level received, a multiple regression model showed that supervised brushing further reduced the three year caries increment (p less than .04). The more frequent use of the higher fluoride dentifrice affords the greatest prevention of decay. The conclusion from this study is that compliance with the supervised brushing program resulted in a reduced caries increment regardless of the level of fluoride in the dentifrice.

Adolescent↗