Melvin L. Moeschberger

Molecular Analysis of Bacterial Species Associated with Childhood Caries

ABSTRACT Although substantial epidemiologic evidence links Streptococcusmutans to caries, the pathobiology of caries may involve more complex communities of bacterial species. Molecular methods for bacterial identification and enumeration now make it possible to more precisely study the microbiota associated with dental caries. The purpose of this study was to compare the bacteria found in early childhood caries (ECC) to those found in caries-free children by using molecular identification methods. Cloning and sequencing of bacterial 16S ribosomal DNAs from a healthy subject and a subject with ECC were used for identification of novel species or uncultivated phylotypes and species not previously associated with dental caries. Ten novel phylotypes were identified. A number of species or phylotypes that may play a role in health or disease were identified and warrant further investigation. In addition, quantitative measurements for 23 previously known bacterial species or species groups were obtained by a reverse capture checkerboard assay for 30 subjects with caries and 30 healthy controls. Significant differences were observed for nine species: S. sanguinis was associated with health and, in order of decreasing cell numbers, Actinomycesgerencseriae, Bifidobacterium, S. mutans, Veillonella, S. salivarius, S. constellatus, S. parasanguinis, and Lactobacillusfermentum were associated with caries. These data suggest that A. gerencseriae and other Actinomyces species may play an important role in caries initiation and that a novel Bifidobacterium may be a major pathogen in deep caries. Further investigation could lead to the identification of targets for biological interventions in the caries process and thereby contribute to improved prevention of and treatment for this significant public health problem.

Factors influencing the one-year mortality of dilated cardiomyopathy

This study was designed to determine prognostic risk indicators of nonischemic dilated cardiomyopathy (DC). Sixty-nine patients were studied. Each patient underwent physical examination (including a history), electrocardiography, echocardiography, cardiac catheterization, 24-hour monitoring and endomyocardial biopsy. The mortality rate at 1 year was 35% (24 deaths). Univariate analysis revealed that the most powerful predictor of prognosis was the left intraventricular conduction delay (p = 0.003). The pulmonary capillary wedge pressure was also predictive of mortality (p = 0.005). Other significant factors, in order of importance, were ventricular arrhythmias (p = 0.007), mean right atrial pressure (p = 0.008), angiographic ejection fraction (p = 0.03), atrial fibrillation or flutter (p = 0.01) and the presence of an S3 gallop (p = 0.05). Factors such as duration of symptoms, presence of mitral regurgitation, end-diastolic diameter, myocardial cell size and percent fibrosis in the biopsy and treatment with vasodilators, antiarrhythmic and anticoagulant drugs were not significant predictors. Multivariate analysis was used to determine which combination of factors could most accurately predict survival and death. The most important factors were left conduction delay, ventricular arrhythmias and mean right atrial pressure. An equation was derived that can be applied to the prognosis of patients with DC. Thus, the clinical assessment of patients with DC can accurately predict the probability of surviving or dying in 1 year.

New Bacterial Species Associated with Chronic Periodontitis

Recent investigations of the human subgingival oral flora based on ribosomal 16S cloning and sequencing have shown many of the bacterial species present to be novel species or phylotypes. The purpose of the present investigation was to identify potential periodontal pathogens among these newly identified species and phylotypes. Species-specific ribosomal 16S primers for PCR amplification were developed for detection of new species. Associations with chronic periodontitis were observed for several new species or phylotypes, including uncultivated clones D084 and BH017 from the Deferribacteres phylum, AU126 from the Bacteroidetes phylum, Megasphaera clone BB166, clone X112 from the OP11 phylum, and clone I025 from the TM7 phylum, and the named species Eubacterium saphenum, Porphyromonas endodontalis, Prevotella denticola, and Cryptobacterium curtum. Species or phylotypes more prevalent in periodontal health included two uncultivated phylotypes, clone W090 from the Deferribacteres phylum and clone BU063 from the Bacteroidetes, and named species Atopobium rimae and Atopobium parvulum.

Identification of Candidate Periodontal Pathogens and Beneficial Species by Quantitative 16S Clonal Analysis

ABSTRACT Most studies of the bacterial etiology of periodontitis have used either culture-based or targeted DNA approaches, and so it is likely that pathogens remain undiscovered. The purpose of this study was to use culture-independent, quantitative analysis of biofilms associated with chronic periodontitis and periodontal health to identify pathogens and beneficial species. Samples from subjects with periodontitis and controls were analyzed using ribosomal 16S cloning and sequencing. Several genera, many of them uncultivated, were associated with periodontitis, the most numerous of which were gram positive, including Peptostreptococcus and Filifactor. The genera Megasphaera and Desulfobulbus were elevated in periodontitis, and the levels of several species or phylotypes of Campylobacter, Selenomonas, Deferribacteres, Dialister, Catonella, Tannerella, Streptococcus, Atopobium, Eubacterium, and Treponema were elevated in disease. Streptococcus and Veillonella spp. were found in high numbers in all samples and accounted for a significantly greater fraction of the microbial community in healthy subjects than in those with periodontitis. The microbial profile of periodontal health also included the less-abundant genera Campylobacter, Abiotrophia, Gemella, Capnocytophaga, and Neisseria. These newly identified candidates outnumbered Porphyromonas gingivalis and other species previously implicated as periodontopathogens, and it is not clear if newly identified and more numerous species may play a more important role in pathogenesis. Finally, more differences were found in the bacterial profile between subjects with periodontitis and healthy subjects than between deep and shallow sites within the same subject. This suggests that chronic periodontitis is the result of a global perturbation of the oral bacterial ecology rather than a disease-site specific microbial shift.

Changes in Periodontal Health Status Are Associated with Bacterial Community Shifts as Assessed by Quantitative 16S Cloning and Sequencing

ABSTRACT The gingival sulcus contains a complex ecosystem that includes many uncultivated bacteria. Understanding the dynamics of this ecosystem in transitions between health and disease is important in advancing our understanding of the bacterial etiology of periodontitis. The objective of this longitudinal study was to examine the stability of bacterial colonization in the gingival crevice and to explore the relationship between shifts in microbial composition and changes in periodontal health status using a comprehensive, quantitative, culture-independent approach. Subgingival plaque samples and periodontal data were collected from 24 subjects over 2 years. Baseline and 2-year plaque samples were analyzed using quantitative ribosomal 16S cloning and sequencing. Ten subjects remained periodontally healthy over 2 years, the periodontal health of seven subjects worsened, and seven subjects showed clinical improvement. Bacterial stability was greatest among healthy, clinically stable subjects and lowest for subjects whose periodontal status worsened (P = 0.01). Higher numbers of species lost or gained were also observed for subjects whose clinical status changed (P = 0.009). This provides evidence that a change in periodontal status is accompanied by shifts within the bacterial community. Based on these data, measures of microbial stability may be useful in clinical diagnosis and prognosis. Regarding individual species, increases in levels of the uncultivated phylotype Veillonella sp. oral clone X042, a gram-negative bacterium and the most common member of the subgingival bacterial community, were associated with periodontal health (P = 0.04), suggesting that this is an important beneficial species. Filifactor alocis, a gram-positive anaerobe, was found at higher levels in subjects with disease (P = 0.01).

Ocular component data in schoolchildren as a function of age and gender.

Purpose. To describe the refractive error and ocular components of a large group of school-aged children as a function of age and gender. Methods. In this report, we describe the refractive error and ocular components of 2583 school-aged children (49.3% girls, overall mean [±SD] age 10.0 ± 2.3). Measurement methods included cycloplegic autorefraction, autokeratometry, videophakometry, and A-scan ultrasonography. For statistical comparisons across gender and age, a critical point of &agr; = 0.005 was used to assess significance because of the large sample size and the large number of comparisons made. Results. Of these 2583 children, 10.1% were myopic (−0.75 D or more myopia in both meridians), and 8.6% were hyperopic (+1.25 D or more hyperopia in both meridians). As would be expected, there was a significant effect of age on refractive error (spherical equivalent, p < 0.0001), toward less hyperopia/more myopia. There was no significant difference in the average refractive error between girls and boys (p = 0.0192). Girls had steeper corneas than boys (0.74 D steeper in the vertical meridian and 0.63 D steeper in the horizontal meridian, p < 0.0001). There were no significant differences in corneal power with age (p = 0.16). Both older age and male gender were significantly associated with deeper anterior chambers (p < 0.0001 for both). The crystalline lens showed significant thinning with age (p < 0.0001), however, there was no significant difference in the lens thickness between girls and boys (p = 0.66). Both Gullstrand lens power and calculated lens power showed significant effects of age and gender (p < 0.0001 for both). Girls, on average, had Gullstrand lens powers that were 0.28 D steeper and calculated lens powers that were 0.80 D more powerful than boys. Axial length also showed significant effects of age and gender (p < 0.0001 for both). Girls’ eyes were, on average, 0.32 mm shorter than those of boys. Conclusions. These cross-sectional data show a general pattern of ocular growth, no change in corneal power, and crystalline lens thinning and flattening between the ages of 6 and 14 years. Girls tended to have steeper corneas, stronger crystalline lenses, and shorter eyes compared with boys.

An acculturation scale for Southeast Asians.

SummaryThis article reports the development of an acculturation scale for Southeast Asian immigrants. From factor analyses of responses on 13 items obtained from samples of three different Southeast Asian ethnic groups, i.e., Cambodians, Laotians, and Vietnamese, two subscales were derived: (1) proficiency in languages (land of origin versus English), and (2) language, social and food (LSF) preferences. Inter-item reliability of the scales was demonstrated for each of the three ethnic groups, with Cronbach alpha coefficients of 0.76 or above. Construct validity was also established within each of the three ethnic groups by demonstrating expected associations of the subscales with current age, years in the USA, total years of education, percentage of lifetime in the USA, and age on entering the USA. Multivariate analyses within each of the ethnic groups revealed that, once controlling for years of education, percentage of lifetime in the USA, and type of health care coverage, although not significant for the Cambodians (P=0.08) males tended to show higher scores for the proficiency in language subscale in comparison to females. Similar multivariate analyses for the LSF preference subscale showed that although slightly higher for the males, the differences between the genders was not significant for the Cambodians (P=0.78); both the Laotian (P=0.23) and Vietnamese (P=0.01) females showed higher scores in comparison to males although only just reaching significance for the Vietnamese.

Effect of Age and Other Factors on Maximal Heart Rate

Abstract In an attempt to reduce the confusion regarding reported effects of age upon maximal exercise heart rate (HR max), a comprehensive review of the English literature was conducted to obtain descriptive statistical data representing over 23,000 independent subjects from 5 to 81 years old. The data were split randomly into two data sets for independent regression analyses. HR max was the dependent variable while independent variables include: age, age2, age3, age4, sex, level of fitness, type of ergometer, exercise protocol, continent of residence, and race. After cross validation the data were pooled and reanalyzed. Additional validation was accomplished on identifiable subsets of the data, e.g., cross sectional, longitudinal, training, comparative ergometry, and comparative sex studies. Results identified negative linear and non-linear age factors, an ergometry factor, a fitness factor and a continent factor. Age accounted for about 70–75% of the variability. Generalized equations were proposed. Ev...

Boron neutron capture therapy of brain tumors: enhanced survival and cure following blood–brain barrier disruption and intracarotid injection of sodium borocaptate and boronophenylalanine

PURPOSE Boronophenylalanine (BPA) and sodium borocaptate (Na(2)B(12)H(11)SH or BSH) have been used clinically for boron neutron capture therapy (BNCT) of high-grade gliomas. These drugs appear to concentrate in tumors by different mechanisms and may target different subpopulations of glioma cells. The purpose of the present study was to determine if the efficacy of BNCT could be further improved in F98-glioma-bearing rats by administering both boron compounds together and by improving their delivery by means of intracarotid (i.c.) injection with or without blood-brain barrier disruption (BBB-D). METHODS AND MATERIALS For biodistribution studies, 10(5) F98 glioma cells were implanted stereotactically into the brains of syngeneic Fischer rats. Eleven to 13 days later animals were injected intravenously (i.v.) with BPA at doses of either 250 or 500 mg/kg body weight (b.w.) in combination with BSH at doses of either 30 or 60 mg/kg b.w. or i.c. with or without BBB-D, which was accomplished by i.c. infusion of a hyperosmotic (25%) solution of mannitol. For BNCT studies, 10(3) F98 glioma cells were implanted intracerebrally, and 14 days later animals were transported to the Brookhaven National Laboratory (BNL). They received BPA (250 mg/kg b.w.) in combination with BSH (30 mg/kg b.w. ) by i.v. or i.c. injection with or without BBB-D, and 2.5 hours later they were irradiated with a collimated beam of thermal neutrons at the BNL Medical Research Reactor. RESULTS The mean tumor boron concentration +/- standard deviation (SD) at 2.5 hours after i. c. injection of BPA (250 mg/kg b.w.) and BSH (30 mg/kg b.w.) was 56. 3 +/- 37.8 microgram/g with BBB-D compared to 20.8 +/- 3.9 microgram/g without BBB-D and 11.2 +/- 1.8 microgram/g after i.v. injection. Doubling the dose of BPA and BSH produced a twofold increase in tumor boron concentrations, but also concomitant increases in normal brain and blood levels, which could have adverse effects. For this reason, the lower boron dose was selected for BNCT studies. The median survival time was 25 days for untreated control rats, 29 days for irradiated controls, 42 days for rats that received BPA and BSH i.v., 53 days following i.c. injection, and 72 days following i.c. injection + BBB-D with subsets of long-term survivors and/or cured animals in the latter two groups. No histopathologic evidence of residual tumor was seen in the brains of cured animals. CONCLUSIONS The combination of BPA and BSH, administered i.c. with BBB-D, yielded a 25% cure rate for the heretofore incurable F98 rat glioma with minimal late radiation-induced brain damage. These results demonstrate that using a combination of boron agents and optimizing their delivery can dramatically improve the efficacy of BNCT in glioma-bearing rats.

Relative Peripheral Refractive Error and the Risk of Onset and Progression of Myopia in Children

PURPOSE To investigate whether relative peripheral hyperopia is a risk factor for either the onset of myopia in children or the rate of myopic progression. METHODS The risk of myopia onset was assessed in 2043 nonmyopic third-grade children (mean age ± SD = 8.8 ± 0.52 years) participating in the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study between 1995 and 2007, 324 of whom became myopic by the eighth grade. Progression analyses used data from 774 myopic children in grades 1 to 8. Foveal and relative peripheral refractive error 30° in the nasal visual field was measured annually by using cycloplegic autorefraction. Axial length was measured by A-scan ultrasonography. RESULTS The association between more hyperopic relative peripheral refractive error in the third grade and the risk of the onset of myopia by the eighth grade varied by ethnic group (Asian children odds ratio [OR] = 1.56, 95% confidence interval [CI] = 1.06-2.30; African-American children OR = 0.75, 95% CI = 0.58-0.96; Hispanics, Native Americans, and whites showed no significant association). Myopia progression was greater per diopter of more hyperopic relative peripheral refractive error, but only by a small amount (-0.024 D per year; P = 0.02). Axial elongation was unrelated to the average relative peripheral refractive error (P = 0.77), regardless of ethnicity. CONCLUSIONS Relative peripheral hyperopia appears to exert little consistent influence on the risk of the onset of myopic refractive error, on the rate of myopia progression, or on axial elongation.