Search PubMed⌕ Search

Biomedical subjects

L J Brown

Publications and source records attributed to L J Brown.

At least 37 records · Page 2Linked to original sources
PubMed2000

Trends in total caries experience: permanent and primary teeth.

BACKGROUND: This article is the last in a series of three that focuses on recent changes in the caries status of children aged 18 years or younger in the United States. METHODS: This study is based on analyses of data regarding total carious (treated and untreated) permanent and primary teeth among children 6 to 18 years old and children 2 to 10 years old from the first and third National Health and Nutrition Examination Surveys, or NHANES I and NHANES III. The NHANES is periodically conducted by the National Center for Health Statistics of the Centers for Disease Control and Prevention. RESULTS: The cumulative number of carious permanent teeth, both treated and untreated, among 6- to 18-year-olds decreased 57.2 percent, from 4.44, as measured in NHANES I, to 1.90, as measured in NHANES III. The cumulative number of carious primary teeth, both treated and untreated, among 2- to 10-year-olds decreased 39.7 percent, from 2.29, as measured in NHANES I, to 1.38, as measured in NHANES III. CONCLUSIONS: Since the 1970s, the cumulative number of carious permanent and primary teeth, both treated and untreated, has declined substantially among children in the United States. PRACTICE IMPLICATIONS: Effective prevention has reduced caries in children. As a result, dental practice will be more focused on maintaining intact dentitions than on repairing teeth damaged by disease.

Adolescent↗
PubMed1999

Cytomegalovirus is not associated with IgM anti-myelin-associated glycoprotein/sulphate-3-glucuronyl paragloboside antibody-associated neuropathy.

Monoclonal antibodies reactive with the HNK-1 epitope of myelin-associated glycoprotein (MAG) and the sulphate-3-glucuronyl paragloboside (SGPG)-like glycolipids are often found in the serum of patients with IgM paraprotein-associated demyelinating neuropathy. The presence of such antibodies in patients with chronic polyneuropathy has recently been associated with evidence of active cytomegalovirus (CMV) infection by the polymerase chain reaction. We wished to test these findings and examined sera from patients with MAG-reactive or MAG-nonreactive paraproteinemic neuropathy and patients with paraproteinemia only for the presence of CMV DNA and anti-CMV antibodies. CMV DNA was not detected in sera from any patient group. Furthermore, anti-CMV antibody prevalence was normal and similar in all 3 groups. We therefore report no evidence of an association between CMV infection and anti-MAG/SGPG antibodies associated with paraproteinemic peripheral neuropathy.

Aged↗
PubMed1999

Trends in untreated caries in permanent teeth of children 6 to 18 years old.

BACKGROUND: This article is the first in a series of three that focus on recent changes in the caries status of children and adolescents in the United States. METHODS: This study is based on analyses of data regarding untreated carious permanent teeth among children 6 to 18 years of age from the first and third National Health and Nutrition Examination Surveys, or NHANES I and NHANES III. The NHANES is periodically conducted by the National Center for Health Statistics of the Centers for Disease Control and Prevention. RESULTS: Overall, the number of carious permanent teeth among children 6 to 18 years old decreased from 1.43, as measured in NHANES I, to 0.33, as measured in NHANES III. The number of carious permanent teeth in children 6 to 18 years old also decreased across four demographic variables: age, sex, race and poverty level. CONCLUSIONS: The number of untreated carious permanent teeth among children has declined dramatically. Since the 1970s, the absolute difference in untreated caries between disadvantaged children and the rest of the child population has narrowed substantially. PRACTICE IMPLICATIONS: The reduction in untreated caries, the major oral disease among children, has been dramatic in all subgroups of children. This may reinforce the already apparent shift from restorative to preventive dental services.

Adolescent↗
PubMed1999

Trends in the dental health work force.

BACKGROUND AND OVERVIEW: Using data from various American Dental Association projects (Distribution of Dentists Survey, the Survey of Dental Practice, the Dental Workforce Model, and the Survey of Predoctoral Dental Educational Institutions), the authors analyzed trends and projections for the dental work force. The article presents work-force projections overall and by sex, when available, through the first 20 years of the 21st century. The number of women practicing dentistry has been increasing rapidly, while the increase in the number of male dentists has been more modest. In the future, the number of female dentists is projected to increase while the number of male dentists is projected to decrease. CONCLUSIONS: Estimates based on the ADA census data place the overall growth in the number of active private practitioners at 19.1 percent between 1982 and 1997. This growth signifies a substantial expansion of capacity to produce dental services in the United States. Growth will be slower in the future. PRACTICE IMPLICATIONS: Changes in the dental work-force capacity and demographic distributions merit careful monitoring and analysis, because they no doubt will determine the dental profession's future ability to deliver needed dental services and influence practitioners level of busyness.

Age Distribution↗
PubMed1999

Trend analysis of dental practice rent and mortgage expenses: 1989-1995.

BACKGROUND: The authors analyzed trends for rent and mortgage, as reported by independent active private practitioners, for the period of 1989-1995. Rent and mortgage were analyzed overall and by different characteristics. METHODS: In the ADA's annual "Survey of Dental Practice," dentists reported gross billings and net incomes, as well as itemized practice expenses. The authors tabulated survey responses over time to develop trends and compare rent and mortgage expenses for each year. If trends over time were not exhibited, the authors combined multiple years of data to develop more reliable statistics. RESULTS: Approximately three-fourths of independent active private practitioners reported rent but no mortgage expenses. The percentages of practitioners who reported rent or mortgage was stable over time. The percentage reporting rent only as an expense increased with the number of dentists in the practice, the age of the reporting dentist and the number of office locations. In contrast, the opposite was true for dentists reporting mortgage only as an expense. CONCLUSIONS: The authors found that office rental is more common than is office ownership and that mortgages as a percentage of gross billings and in dollar amounts were similar to rents. They also found that because the cost of office space as a percentage of gross billings decreased as the number of dentists in the practice increased, limited economies of scale may be present in the cost of dental office space. PRACTICE IMPLICATIONS: There is not a large financial advantage to ownership, so renting is likely to remain an important way to acquire office space. As only limited economies of scale exist in office space expenses, many group practices may choose to rent office space.

Capital Expenditures↗
PubMed1999

Dental care utilization: how saturated is the patient market?

BACKGROUND: Dental care utilization is the percentage of the population who access dental services over a specified period. In this article, the authors report on the results of several dental care utilization studies. METHODS: To date, dental utilization data have been gathered by large national studies via telephone interviews, face-to-face interviews or written surveys. In this article, the authors report on and compare dental care utilization rates provided by the Centers for Disease Control and Prevention, the National Center for Health Statistics, the Agency for Health Care Policy and Research and the American Dental Association. RESULTS: As captured by the various studies, the percentage of people who indicated they visited a dentist within the past year increased gradually between 1983 and 1997. The authors found that dental care utilization rates are higher among women than they are among men, and they decrease with age and increase with income and educational level. CONCLUSIONS: Although the available data vary, they suggest that more Americans are visiting a dentist. The demand for dental care is increasing overall, as well as across educational, racial and economic lines. PRACTICE IMPLICATIONS: If, as recent studies suggest, approximately 75 percent of the population visits a dentist annually, there is only modest room for further expansion of dental care utilization. However, if dental care utilization rates are substantially lower as reported in older studies, then there is a greater potential for increased dental care utilization.

Adult↗
PubMed1999

Retirement savings of dentists in private practice.

BACKGROUND: Retirement planning is an issue that concerns all working people. In this article, the authors present their analysis of the results of a 1995 American Dental Association survey that asked dentists questions about their plans to finance their retirement. METHODS: The ADA's Survey Center conducts a periodic "Survey of Current Issues in Dentistry," which gauges dentists' opinions about a variety of topics of interest to dentistry. The authors analyzed the results of the 1995 survey in which retirement savings was one of the topics. RESULTS: The majority of responding owner/dentists whose primary occupation was private practice (40.7 percent) indicated that they were relying only "a little" on the sales of their practices to finance their retirements. Overall, dentists whose primary occupation was private practice reported saving an average of 10.5 percent of their income specifically for retirement. The average total amount of money dentists invested in various retirement plans increased with age and was highest for the 55 to 59 and the 60 to 64 years of age cohorts. The only exception was the 401(k) plan, in which the peak occurred in the 65 years of age and older cohort. CONCLUSIONS: Fifteen years ago most dentists retired between the ages of 60 and 69 years. Recent trends show that dentists are retiring at younger ages. This means that while in practice, dentists must save enough to support themselves for 20 or more years of retirement. PRACTICE IMPLICATIONS: The transition from private practice to retirement can be difficult. Therefore, planning for the future is important. Dentists can benefit from making appropriate decisions based on age, investment goals, risk tolerance, monetary constraints and time until retirement.

Adult↗
PubMed1998

EPR and CD spectroscopy of fast myosin light chain conformation during binding of trifluoperazine.

The conformations of isolated rabbit fast myosin light chains (LCs) were modified using trifluoperazine (TFP), the hydrophobic calmodulin inhibitor. CD spectroscopy showed that TFP altered secondary structural content of the LCs, with half-maximal effects at TFP concentrations of approximately 14-50 microM, which is within the range required to alter muscle fiber contraction in both agonistic and antagonistic ways [Kurebayashi, N. & Ogawa, Y. (1988) J. Physiol. 403, 407-424]. EPR spectroscopy provided structural information from paramagnetic probes on C-terminal domain surfaces. In the absence of TFP, tauR (rotational correlation time) was 1.6 ns for both alkali light chains (ALCs) and 1.8 ns for light chain 2 (LC2). This was faster than expected for proteins of this size (approximately 10 ns). TFP progressively recruited the probes into populations with tauR sevenfold to 12-fold slower, with half-maximal effects at a TFP concentration of approximately 370-800 microM. The differences probably indicate that CD spectroscopy detects changes in protein conformation due to 'specific' TFP binding at the LC hydrophobic core, while less specific binding at higher TFP concentrations is required to effect conformational changes on the protein surfaces near the paramagnetic probes. TFP binding was generally not cooperative. Comparative sequence analysis between calmodulin, troponin C, and myosin LCs indicated considerable conservation between residues expected to bind TFP.

Amino Acid Sequence↗
PubMed1998

A population-based study of bone mineral density in women with longstanding type 1 (insulin dependent) diabetes.

This study aimed to explore multiple determinants of BMD (bone mineral density) in 99 women with long-standing type 1 diabetes, recruited from a population based register of insulin users. BMD was measured using DEXA (dual energy X-ray absorptiometry) at the femoral neck and lumbar spine, age adjusted Z scores were calculated and results compared to those of healthy volunteers. The median age of diabetic subjects was 42 years and the median duration of diabetes was 27 years. BMD was positively associated with body mass index and height at both the lumbar spine and femoral neck. There was a positive association with oral contraceptive pill use and lumbar spine BMD, and peripheral vascular disease was negatively associated with femoral neck BMD. No correlation was seen with either age or duration of diabetes and absolute BMD values. Mean Z score at the femoral neck was -0.12 (95% confidence interval -0.37 to +0.12). At the lumbar spine, the corresponding value was -0.21 (-0.44 to +0.02). Pre- and post-menopausal values for the diabetic subjects and healthy volunteers were found to be similar. In summary, axial BMD values in subjects with long-standing diabetes were similar to those observed in healthy non diabetic populations.

Adult↗
PubMed1998

Gingival inflammation and subgingival calculus as determinants of disease progression in early-onset periodontitis.

This study was undertaken to test the hypothesis that gingival inflammation and dental calculus are important determinants of the development and progression of early-onset periodontitis. The study sample included 156 individuals who were 13-20 years old at baseline and who were examined 2x during 6 years to assess the attachment loss, gingival state and the presence of dental calculus. 33 (21%), 62 (40%), and 61 (39%) individuals were classified as having localized, generalized, or incidental EOP, respectively. The results showed an increase in the % of teeth with overt gingivitis and subgingival calculus, and also an increase in the % of teeth showing attachment loss during the 6-year period in all classification groups. Of teeth with 0-2 mm attachment loss at the beginning of the study and which developed > or = 3 mm attachment loss during the following 6 years, there were 2x as many teeth with overt gingival inflammation, and 4x more teeth with subgingival calculus at baseline than teeth without. Gingivitis and subgingival calculus when present at both examinations resulted in a stronger association with the development of new lesions than presence of these variables at baseline. Teeth with gingivitis at baseline had a significantly higher mean attachment loss during 6 years than teeth without gingivitis (p<0.0001), and teeth with subgingival calculus at baseline had a significantly higher mean attachment loss than teeth without subgingival calculus (p<0.0001). The presence of gingivitis and subgingival calculus at baseline and 6 years later was associated with the occurrence of even higher disease progression during this period. The association between gingival inflammation and subgingival calculus and the development and progression of attachment loss during the study period in the generalized and the localized EOP groups was significantly higher than the association in the incidental EOP group. In an appreciable % of the sites in all 3 groups, however, the presence of the 2 factors was not associated with attachment loss during 6 years. The results suggest a significant association between gingival inflammation and subgingival calculus and the development and progression of early-onset periodontitis.

Adolescent↗
PubMed1998

Borderline malignant change in recurrent müllerian papilloma of the vagina.

Malignant change occurred in a benign, recurrent vaginal müllerian polyp. The patient, a 49 year old woman with cerebral palsy, presented with a polypoid mass in the vagina. At four years of age she had presented with a haemorrhagic polyp, and over the following years she had recurrent irregular bleeding and regrowth of the polypoidal mass, requiring a total of 10 operations to excise the polyp. Histological examination of the specimen showed typical müllerian features with tubal, endometrioid, and endocervical cell types. There were significantly abnormal nuclei, indicating low grade or borderline malignancy. Review of previous biopsies showed similar müllerian features but no atypia. This is the first reported case of borderline malignant change in a previously benign recurrent müllerian papilloma of the vagina. Definitive radical surgery or radiotherapy is contraindicated in this patient and she remains under follow up.

Disease Progression↗
PubMed1998

Effects of estrogen status and aging on salivary flow rates in healthy Caucasian women.

A comparison of salivary flow rates was made between three groups of female individuals according to their menopausal status. The three groups consisted of healthy, dentate, nonmedicated women (with the exception of the use of estrogen) from the Baltimore Longitudinal Study of Aging. One group consisted of premenopausal women (n = 51), their mean age was 39 years. Another group (n = 26) was perimenopausal with a mean age of 48 years. A third group (n = 76) was postmenopausal with a mean age of 69 years. The groups were evaluated for unstimulated (UPAR) and stimulated parotid gland flow rates (SPAR), unstimulated (USUB) and stimulated submandibular/sublingual gland flow rates (SSUB), and stimulated whole-saliva flow rates (SWHOLE). The parotid flow rates were determined using a Carlson-Crittenden cup, while the submandibular/sublingual flow rates were determined using the National Institute of Dental Research collector. A 2% citrate solution was used for stimulation in glandular collections. Chewing a 1-cm3 cube of paraffin was used to stimulate whole saliva. The results showed no significant differences in UPAR, SPAR, and SWHOLE between the three groups. However, the premenopausal women had higher USUB than the postmenopausal group. The premenopausal women also had higher SSUB than perimenopausal and postmenopausal groups. There were no differences in salivary flow rates between those taking estrogen and those that were not medicated.

Adult↗
PubMed1998

Mercury concentrations in urine and whole blood associated with amalgam exposure in a US military population.

Minute amounts of mercury vapor are released from dental amalgams. Since mercury vapor is known to be associated with adverse health effects from occupationally exposed persons, questions regarding the margin of safety for exposure to mercury vapor in the general population continue to be raised. To address this issue, one needs information regarding exposure to mercury vapor from dental amalgam fillings and its possible consequences for health in the general population. The NIDR Amalgam Study is designed to obtain precise information on amalgam exposure and health outcomes for a non-occupationally-exposed population of US adults. One hypothesis was that in a generally healthy population a significant association between amalgam exposure and Hg levels in urine and/or whole blood could be detected. The cohort investigated was an adult military population of 1127 healthy males. Their average age was 52.8 years, and their ages varied from 40 to 78 years. Ninety-five percent of the study participants were white males, and slightly over 50% had some college education. Five percent were edentulous. The dentate participants, on average, had 25 natural teeth, 36.9 decayed or filled surfaces (DFS), and 19.9 surfaces exposed to amalgam, with amalgam exposure varying from 0 to 66 surfaces. Their average total and inorganic urinary mercury concentrations were 3.09 microg/L and 2.88 microg/L. The average whole-blood total and inorganic mercury concentrations were 2.55 microg/L and 0.54 microg/L. Significant correlations were detected between amalgam exposure and the total (r = 0.34, p < 0.001) and inorganic 0.34 (r = 0.34, p < 0.001) urinary mercury concentrations on the original scale. Stronger correlations were found for total (r = 0.44, p < 0.001) and inorganic (r = 0.41, p < 0.001) urinary Hg on the log scale, as well as for creatinine-corrected total (r = 0.43, p < 0.001) and inorganic (r = 0.43, p < 0.001) urine concentrations. In whole blood, statistically significant, but biologically weak, correlations were detected for total (r = 0.09, p = 0.005) and inorganic (r = 0.15, p < 0.001) Hg concentrations, respectively. Based on these cross-sectional data, it is estimated that, on average, each ten-surface increase in amalgam exposure is associated with an increase of 1 microg/L mercury in urine concentration.

Adult↗
PubMed1998

Dental expenditures by selected dentist and practice characteristics.

Total estimated dental expenditures in 1995 were approximately $47.6 billion as reported by the Bureau of Economic Analysis, or BEA. According to the Health Care Financing Administration, or HCFA, the total estimated dental expenditures in 1995 were approximately $44.7 billion. Using the reported gross billings from the annual ADA "Survey of Dental Practice," the authors estimated that the total national dental expenditures in 1995 were about $45.5 billion. As this estimate falls between the BEA- and HCFA-estimated total dental expenditures, it is one confirmation of the reliability and validity of ADA's estimates. This estimate also can be used to look at dental expenditures by selected characteristics--such as specialty, office time and number of dentists in the practice.

American Dental Association↗
PubMed1998

Trend analysis of dental expenditures by selected dentist and practice characteristics, 1985-1995.

Using the reported gross billings from the annual ADA "Survey of Dental Practice," the authors estimated the total national dental expenditures according to various dentist characteristics for the period of 1985-1995. These selected characteristics are specialty, office time, number of dentists in the practice, sex, length of experience and U.S. region. As government agencies do not report dental expenditures by such dentist characteristics, the data presented in this article may be the first of their kind to be estimated and published.

Accounting↗