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Biomedical subjects

L J Brown

Publications and source records attributed to L J Brown.

At least 91 records · Page 5Linked to original sources
PubMed1995

Improved periodontal status through self-assessment. A 2-year longitudinal study in teenagers.

Short-term success of the use of self-assessment for motivating adults to improve their oral health status has been reported. The purpose of this trial was to evaluate the long-term effectiveness of two self-assessment strategies, one focused on gingival bleeding (group I) and another focused on plaque (group II). At baseline, 493 14- and 15-year-olds were assigned randomly to a group. Each subject was given a manual describing one of the self-assessment processes. Dental hygienists provided standardized classroom based instruction and two weeks later, individualized counselling. Examinations were conducted at baseline 6, 12, 18 and 24 months for gingival bleeding on probing, plaque, calculus, and probing depth; and at baseline and 24 months for recession and decayed, missing and filled surfaces (DMFS). Following the 12-month examination, subjects received an oral prophylaxis and individual counselling. The results revealed no statistically significant differences between groups for any clinical parameter at the final examination. However, the mean number of sites with gingival bleeding decreased steadily from baseline to 24 months with a 59% decrease and 55% decrease for groups I and II, respectively. This study suggests that self-assessment approaches can be effective in improving the long-term periodontal health status of teenagers.

Adolescent↗
PubMed1995

The impact of recent changes in the epidemiology of dental caries on guidelines for the use of dental sealants.

This paper reviews recent changes in the epidemiology of dental caries and assesses their potential impact on the diagnosis and management of the disease and the planning and operation of sealant programs. These changes, such as the decline in caries and slowing of the rate of progression of the disease, have important implications for diagnosing and treating incipient lesions, predicting caries risk, and conducting effective disease preventive programs. Traditional paradigms for restoring carious lesions are being replaced by newer strategies that emphasize disease prevention and conservation of tooth structure. The search continues for the identification of practical models for predicting caries risk at the individual level. This paper describes a method useful for targeting resources in sealant placement programs by enabling one to determine the relative effectiveness of sealing alternative tooth surfaces in the oral cavity. One guide serves as a widely adopted manual for those who use or intend to use dental sealants in caries prevention programs. This paper provides a brief review of that document, "Preventing Pit and Fissure Caries: A Guide to Sealant Use," as well as guidelines for sealant utilization provided by the American Dental Association, and information regarding dental sealant programs under Medicaid. The final portion of the paper provides a synthesis of the epidemiology reviewed and summarizes the implications of findings for sealant programs.

Adolescent↗
PubMed1995

How fee and insurance changes could affect dentistry: results from a microsimulation model.

Dentists have become concerned about the possible impact of reductions in dental insurance coverage. The authors used a microsimulation model of the dental sector to assess the potential impact of reductions in the percentage of Americans with dental insurance, in universal dental insurance coverage for children and in fees paid to dentists for their services. The model predicted that reductions in dental insurance coverage would reduce per capita dental expenditures, but that the impact would not be large. Fee reductions had the greatest impact on dental expenditures of any change simulated by the model.

Adolescent↗
PubMed1995

Immunogenetic, clinical, and demographic characterization of childhood type I diabetes in New Zealand.

OBJECTIVE: To examine the relationship between genetic susceptibility alleles and islet cell antibodies (ICAs) in type I diabetes. RESEARCH DESIGN AND METHODS: The human leukocyte antigen (HLA)-DQB1 alleles and ICA levels of all incident type I diabetic cases in patients < 20 years of age diagnosed in 1990 and 1991 in Canterbury, New Zealand, were determined. RESULTS: The mean annual incidence rate for type I diabetes over the 24 months was 19.0/100,000 patient-years (95% confidence interval [CI] 13.5-26.0/100,000), which was considerably higher than rates observed between 1982 and 1989 (11.7/100,000; 95% CI 9.6-14.3/100,000). ICAs > or = 10 Juvenile Diabetes Foundation units (JDF U) were present in 84.6% of the subjects, but there was a higher prevalence of ICA-negative (ICA-) subjects among those diagnosed during the winter months. The frequencies of the susceptibility allele DQB1*0302 and susceptibility genotype 0302/0201 were 71.8% and 43.5%, respectively. Subjects with 0302 tended to be younger (mean age 8.3 +/- 5.1 years) than those with nonsusceptibility types (mean age 11.8 +/- 4.7 years, P = 0.056). The probability of being ICA positive (ICA+) was not significantly different between subjects with allele 0302 (85.7%) and those without it (81.8%). All seven patients negative for ICA were homozygous for DQB1 nonaspartate-57. There was no clustering of the immunogenetic markers with demographic and clinical characteristics apart from age at diagnosis. CONCLUSIONS: No direct relationship was observed between DQB1-defined genetic susceptibility and ICA at diagnosis, suggesting that variations at the DQB1 locus are not linked to the expression of this autoimmune marker of beta-cell destruction.

Adolescent↗
PubMed1994

The sequence of a human mitochondrial glycerol-3-phosphate dehydrogenase-encoding cDNA.

A 2618-bp cDNA that encodes the human mitochondrial glycerol-3-phosphate dehydrogenase has been isolated from a HeLa cell cDNA library and the nucleotide sequence determined. An open reading frame encodes a protein of 727 amino acids that is 96% similar to the rat protein and, like the rat protein, contains sites homologous to the Ca(2+)-binding sites of calmodulin, as well as FAD- and putative glycerol-phosphate-binding sites.

Amino Acid Sequence↗
PubMed1994

Attitudes and knowledge regarding contraception and prepregnancy counselling in insulin dependent diabetes.

AIMS: To assess knowledge and attitudes of women with insulin dependent diabetes to contraception, prepregnancy planning, and genetic risk. METHOD: Women with insulin dependent diabetes, aged 18 to 40, were identified from a population-based register of insulin users in North Canterbury. Participating subjects underwent a structured face to face interview, assessing current contraceptive practices and their knowledge and attitudes to the areas outlined above. RESULTS: One hundred and twenty four women, representing 86% of eligible women, agreed to participate. Eighty five subjects were using some form of contraception. The most popular choices were the combined oral contraceptive pill (35%), the progesterone only pill (12%), condoms (24%), vasectomy (12%) and tubal ligation (12%). All subjects recognised the importance of good blood glucose control during pregnancy. Thirty nine percent of subjects using contraception avoided the combined oral contraceptive pill because of concerns about metabolic and vascular side effects. Only 52% of subjects knew the correct figure for genetic risk of passing insulin dependent diabetes on to an offspring. CONCLUSIONS: Patient education regarding the need for prepregnancy planning in women with insulin dependent diabetes appeared adequate and the percentage of subjects using contraception was higher than that described in overseas diabetic populations. Over a third of subjects were however concerned about the risks of contraceptive options in insulin dependent diabetes, particularly with regard to the use of the combined oral contraceptive pill. This finding suggests that discussion about the advantages and disadvantages of contraceptive choices should be an integral part of patient education for women with insulin dependent diabetes mellitus of child-bearing age. Knowledge about genetic risk was inadequate in half the subjects interviewed, and this area of patient education could also be improved.

Adolescent↗
PubMed1994

Sequence of rat mitochondrial glycerol-3-phosphate dehydrogenase cDNA. Evidence for EF-hand calcium-binding domains.

The FAD-dependent, mitochondrial glycerol-3-phosphate dehydrogenase (EC 1.1.99.5) is an essential component of the glycerol phosphate shuttle and is abundant in the pancreatic insulin cell, skeletal muscle, and brain. Although DNA clones for this enzyme and its homologues have been isolated from bacteria and yeast, it has never been cloned from a higher eukaryote. We have cloned and sequenced cDNAs encoding the rat mitochondrial glycerol-3-phosphate dehydrogenase. The longest cDNA (2337 base pairs) encodes a deduced protein of 727 amino acids that shows strong homology to the yeast and bacterial FAD-dependent glycerol phosphate dehydrogenases. The amino terminus of the purified mature protein was sequenced and shows identity with the deduced amino acid sequence beginning with residue 43. The 42 preceding amino acids are consistent with a mitochondrial leader peptide. A highly conserved FAD-binding domain and conserved regions possibly involved with glycerol phosphate binding are present. An unexpected finding was the homology of the deduced protein to calmodulin. Analysis of the deduced protein sequence shows a region near the carboxyl terminus containing two sequences homologous to "EF-hand" calcium-binding domains that are not present in the shorter yeast and bacterial homologues. The second of these domains appears to have features compatible with considerable affinity for calcium, whereas the first does not. The finding of a potential calcium-binding region is consistent with the known enhancement by calcium of the mammalian enzyme activity at low substrate concentrations and the lack of a requirement for calmodulin. This is the first report of EF-hands in a metabolic enzyme or in a mitochondrial protein.

Amino Acid Sequence↗
PubMed1994

Low lactate dehydrogenase and high mitochondrial glycerol phosphate dehydrogenase in pancreatic beta-cells. Potential role in nutrient sensing.

Nutrient metabolism was examined with regard to insulin secretion in purified rat islet beta- and non-beta-cells, beta-cell lines, and hepatocytes. Lactate dehydrogenase (LDH) activity (nanomoles.min-1.mg protein-1) was remarkably low in the glucose-sensitive INS-1 cell line (15.7) and in beta-cells (22.3). Thus, beta-cell LDH was respectively 8-, 122-, 17-, and 136-fold lower than in islet non-beta, liver, HIT-T15, and RINm5F cells. Plasma membrane lactate transport activity was 3-10-fold lower in beta- or INS-1 cells than in the other cell types. Conversely, mitochondrial glycerol phosphate dehydrogenase was strongly expressed only in beta- and INS-1 cells. The significance of these findings to nutrient recognition was explored using INS-1 cells as a model of native beta-cells. Glucose-stimulated lactate output and glucose utilization were, respectively, 12- and 5-fold lower in INS-1 than in RINm5F cells. Each process was entirely blocked by respiratory chain inhibitors in INS-1 cells, whereas glucose utilization was barely affected and lactate output stimulated in RINm5F cells. Glucose oxidation represented 73% of total utilization in INS-1 cells, but only 9% in RINm5F cells. Absolute rates of glucose oxidation, and the extent of mitochondrial NAD(P) reduction, were similar in the two cell types, and glucose stimulated insulin secretion 1.9-fold in INS-1 and 1.4-fold in RINm5F cells. The mitochondrial substrates, monomethyl succinate, pyruvate, and leucine, each triggered secretion in INS-1 cells. The balance of LDH, plasma membrane lactate transport, and mitochondrial glycerol phosphate dehydrogenase activities therefore appear to be important in beta- and INS-1 cell glucose recognition to ensure that mitochondrial oxidation is the principle fate of pyruvate and NADH produced by glycolysis. The resultant close coupling of glycolysis with mitochondrial oxidation explains the absence in beta-cells of Crabtree and Pasteur effects.

Animals↗
PubMed1994

Comparison of stimulated parotid salivary gland flow rates in normotensive and hypertensive persons.

Although hypertension is a prevalent condition among the elderly, little is known with respect to the influence of hypertension on oral health and function. Therefore a study was conducted that compared stimulated parotid salivary flow rates in elderly persons (65 years and older) from two diverse populations who are normotensive, mild, and severe hypertensive. The normotensive group consisted of 45 healthy subjects with systolic blood pressures of less than 140 mm Hg and diastolic pressures less than 90 mm Hg. The mildly hypertensive group consisted of 14 otherwise healthy subjects with either systolic pressures greater than 140 mm Hg or diastolic pressures greater than 90 mm Hg. The severely hypertensive group consisted of 10 otherwise healthy subjects with either systolic pressures greater than 180 mm Hg and/or diastolic pressures greater than 100 mm Hg. All three groups were not taking any prescription or nonprescription medications. Samples of 2% citrate-stimulated parotid saliva were collected from each subject. The results showed no significant differences in stimulated parotid flow between normotensive, mildly hypertensive, and severely hypertensive subjects. These results suggest that hypertension per se has no influence on stimulated parotid salivary gland flow rates in otherwise healthy, elderly unmedicated white and African-American persons.

Aged↗
PubMed1994

Retinoic acid suppression of loricrin expression in reconstituted human skin cultured at the liquid-air interface.

Retinoids have been shown to modulate the expression of proteins involved in epidermal differentiation. To examine this effect in an in vitro skin model, we evaluated the effect of retinoic acid on the expression of two cell envelope proteins, loricrin and involucrin, and an early marker of epidermal differentiation, keratin 1, in a reconstituted human skin equivalent cultured at the liquid-air interface. Retinoic acid, a known inhibitor of keratinization in monolayer and raft cultures, was evaluated for its ability to alter the expression and distribution of these markers of epidermal differentiation. Retinoic acid (10(-6) M) suppressed loricrin expression in skin cultures as determined by both protein and mRNA analysis. In contrast, no inhibition of involucrin or K1 expression was observed at the protein level at the same retinoic acid concentration. However, some suppression of K1 mRNA transcription was observed in retinoic acid-treated cultures. These results demonstrate that in differentiating cultures of reconstituted human skin, loricrin expression is markedly inhibited by retinoids, K1 less so, and involucrin not at all.

Base Sequence↗
PubMed1994

A comparative study of costs for dental services and dentists' income in the United States and Norway.

The United States and Norway have approximately the same per capita Gross Domestic Product (GDP) and average personal income, but their per capita health spending patterns are quite different. In 1982, the US spent 6.5% of its total health expenditures on dental services while Norway spent 5.4%. A higher percentage of Norwegian adults see a dentist annually as compared to US adults. In 1984, the mean net income of dentists in private practice was $66,940 in the US and $27,125 in Norway; this is respectively 5 and 1 3/4 times the average per capita income in those countries. The American publicly-employed dentist earned approximately two-thirds of what the American private practitioner made, while still earning approximately 50% more than his Norwegian counterpart. Some basic information concerning the ratios of dentists, specialists, and dental hygienists to the population is given. The relative proportion of women dentists in the two countries is contrasted. Finally, data on graduates from the dental schools, enrollment cuts, and estimated dentist to population ratios by the year 2000 are described to compare future manpower that will be available to the two countries. Several dissimilarities in the political and social systems are described and discussed. It is emphasized that caution should be used when interpreting and comparing data about countries with different dental delivery, political, and social systems.

Dental Health Services↗
PubMed1994

Stimulated parotid salivary flow rates in normotensive, hypertensive, and hydrochlorothiazide-medicated.

Stimulated parotid salivary flow rates were compared in elderly normotensive, hypertensive, and controlled hypertensive African-Americans, the latter group taking hydrochlorothiazide (HCTZ). The normotensive group consisted of 15 healthy unmedicated subjects with systolic blood pressures of less than 150 mm Hg and diastolic pressures less than 90 mm Hg. The hypertensive group consisted of 10 unmedicated subjects with systolic pressures greater than 160 mm Hg and diastolic pressures greater than 100 mm Hg. The controlled hypertensive group consisted of 20 subjects taking HCTZ (50 mg, daily) with controlled blood pressures similar to the normotensive control group. Stimulated parotid salivary samples were collected from each subject. A 2% citrate solution applied to the dorsum of the tongue was used for stimulation. The results showed no significant differences in stimulated parotid flow rates between normotensive and uncontrolled hypertensive subjects. However, the medicated, controlled hypertensive subjects had a significant reduction of stimulated parotid salivary flow rates compared to both the normotensive and hypertensive groups.

Aged↗
PubMed1994

Trends in tooth loss among U.S. employed adults from 1971 to 1985.

A comparison of data from a 1971-74 study and a 1985-86 study is used to establish trends in tooth loss among adults. The data show that tooth retention among employed U.S. adults improved almost 15 percent in the decade between the two studies, and edentulism was almost cut in half.

Adolescent↗
PubMed1994

Utilization of dental services as a risk factor for periodontitis.

The relation between utilization of dental services from community dentists and the extent and severity of alveolar bone loss is reported for a panel of men followed for over 6 years. Oral health data were collected by the Department of Veterans Affairs, Dental Longitudinal Study, which began in 1969 and still continues. Participants have received regular oral examinations approximately every 3 years. A variety of oral health conditions were assessed, including plaque, calculus, gingival inflammation, probing depth, tooth mobility, clinical attachment level, and alveolar bone loss. Utilization data were abstracted from the dental records of dental offices that participants attended from 1979 through 1988. Multivariate modeling as well as comparisons of high utilizers and non-utilizers indicate that utilization of routine diagnostic and preventive services was not predictive of the extent and severity of periodontitis.

Alveolar Bone Loss↗