Biomedical subjects

C M Carey

Publications and source records attributed to C M Carey.

At least 19 recordsLinked to original sources

PubMed2006

Effect of a calcium prerinse on salivary fluoride after a 228-ppm fluoride rinse.

The objective of this study was to determine if a concentrated calcium prerinse given before a fluoride rinse would cause an increase in the post rinse sali vary fluoride (F). A panel of 5 subjects used a 30, 150 or 300 mmol/l calcium lactate prerinse followed by a 1-min NaF rinse. All calcium prerinses significantly increased the 1-hour saliva F relative to the NaF control without a prerinse. The maximum increase was produced by the 150 mmol/l calcium lactate prerinse and was about ninefold higher than the NaF control.

Calcium Compounds↗

PubMed2006

Salivary fluoride from fluoride dentifrices or rinses after use of a calcium pre-rinse or calcium dentifrice.

The low concentration of available calcium (Ca) in oral fluids limits the formation of Ca-mediated fluoride deposits that maintain oral fluoride (F) after a topical F treatment. The purpose of this study was to examine if a high concentration of Ca would increase salivary F when used before a F rinse or dentifrice. We found that a Ca pre-rinse (150 mmol/l Ca lactate) or Ca dentifrice (0.084 g Ca glycerolphosphate per gram dentifrice) used immediately before a 60 s 228-ppm F rinse (12 mmol/l NaF) produced a 4.6x or 3.6x increase (p < 0.05) respectively in the 1 h salivary F concentrations over the F rinse alone. Reducing the post-Ca F rinse to 10 s still produced a significant 2.2x increase in salivary F compared to the 60 s F rinse alone. Used with a conventional 1,100 ppm F (i.e. 1,100 microg F per gram) NaF dentifrice (Crest), the above Ca pre-rinse increased 1 h salivary F levels by 2.3x over the F dentifrice alone. However, a F rinse given before a Ca rinse produced no increase in 1 h salivary F concentrations. Although the persistence of these increases requires further study, these results suggest that a moderately high concentration of Ca given shortly before a F rinse or F dentifrice may increase the cariostatic effect of the F product.

Biological Availability↗

PubMed2004

Biology, persistence and detection of Cryptosporidium parvum and Cryptosporidium hominis oocyst.

Cryptosporidium parvum and Cryptosporidium hominis are obligate enteric protozoan parasites which infect the gastrointestinal tract of animals and humans. The mechanism(s) by which these parasites cause gastrointestinal distress in their hosts is not well understood. The risk of waterborne transmission of Cryptosporidium is a serious global issue in drinking water safety. Oocysts from these organisms are extremely robust, prevalent in source water supplies and capable of surviving in the environment for extended periods of time. Resistance to conventional water treatment by chlorination, lack of correlation with biological indicator microorganisms and the absence of adequate methods to detect the presence of infectious oocysts necessitates the development of consistent and effective means of parasite removal from the water supply. Additional research into improving water treatment and sewage treatment practices is needed, particularly in testing the efficiency of ozone in oocyst inactivation. Timely and efficient detection of infectious C. parvum and C. hominis oocysts in environmental samples requires the development of rapid and sensitive techniques for the concentration, purification and detection of these parasites. A major factor confounding proper detection remains the inability to adequately and efficiently concentrate oocysts from environmental samples, while limiting the presence of extraneous materials. Molecular-based techniques are the most promising methods for the sensitive and accurate detection of C. parvum and C. hominis. With the availability of numerous target sequences, RT-PCR will likely emerge as an important method to assess oocyst viability. In addition, a multiplex PCR for the simultaneous detection of C. parvum, C. hominis and other waterborne pathogens such as Giardia lamblia would greatly benefit the water industry and protect human health.

Animals↗

PubMed2004

Hypertriglyceridaemia in Alström's syndrome: causes and associations in 37 cases.

OBJECTIVE: To document frequency of severe hypertriglyceridaemia in Alström's syndrome (AS) and its relationship to hepatic and renal function, glycaemia and insulin resistance. PATIENTS AND METHODS: Thirty-seven subjects with AS aged 5-35 years, 51% male, were assessed at multidisciplinary clinics in Canada, UK and Italy. Diagnostic criteria were: severe cone/rod dystrophy leading to severe visual impairment in early childhood, sensorineural deafness, moderate overall obesity and normal intelligence. Three patients were treated with thyroxine for primary hypothyroidism and one female patient for secondary amenorrhoea with 20 micro g ethinyloestradial combined oral contraceptive. Two male patients were receiving monthly intramuscular testosterone enanthate for secondary hypogonadism. Fasting bloods were taken for serum insulin, serum glucose, serum triglycerides, hepatic and renal function and glycosylated Hb. Triglyceride levels > 8 mmol/l and fasting serum insulin levels > 16 microunits/ml were considered to represent severe hypertriglyceridaemia and severe insulin resistance, respectively. All subjects with (23) hypertriglyceridaemia also had high insulin resistance, as measured by HOMA modelling. However, there was no significant correlation between log tyriglyceride and log serum insulin or HOMA in the whole group (P = 0.2 and 0.14, respectively). There was no clear relationship between serum triglyceride levels and age, body mass index (BMI), hepatic or renal impairment or glycaemia. CONCLUSION: The first overview of serum triglyceride levels in a significant number of reported cases of Alström Syndrome shows an overlap between severe hypertriglyceridaemia and severe hyperinsulinism, but not a direct correlation between the two nor with insulin resistance measured by HOMA. Triglyceride levels were not related to glycaemia, hepatic or renal dysfunction.

Adolescent↗

PubMed2003

Fluoride release from a resin-modified glass-ionomer cement in a continuous-flow system. Effect of pH.

Fluoride is added to many dental restorative materials, including glass-ionomer cements, for the specific purpose of leaching fluoride into the surrounding tissues to provide secondary caries inhibition. During the caries process, an acidic environment attacks the dental tissues as well as the glass-ionomer cement. We hypothesized that pH significantly affects the rate of release of fluoride from the glass-ionomer cement. A continuous-flow fluoride-measuring system that monitors the amount of fluoride released over time was used to determine the release of fluoride from a resin-modified glass-ionomer cement (KetacFil). The results show that the release rate began with a fast burst of fluoride which quickly diminished to low levels in 3 days. Under neutral pH conditions, the rate of fluoride release at 72 hrs was significantly slower than at pH 4.

Cariostatic Agents↗

PubMed2000

Composition of plaque and saliva following use of an alpha-tricalcium-phosphate-containing chewing gum and a subsequent sucrose challenge.

Previous studies demonstrated that the chewing of a 2.5% (mass fraction) alpha-tricalcium-phosphate-fortified (alpha-TCP) experimental chewing gum released sufficient calcium and phosphate to eliminate any fall in the tooth mineral saturation of plaque fluid after a sucrose rinse (Vogel et al., 1998). In contrast, the chewing of a conventional sugar-free gum did not eliminate this decrease in saturation. The purpose of this study was to examine if the release of ions from plaque calcium-phosphate pools induced by this gum could provide protection during subsequent exposure to cariogenic conditions. Fourteen subjects accumulated plaque for 48 hrs, fasted overnight, chewed a control or experimental gum for 15 min, and subsequently rinsed 1 min with a mass fraction 10% sucrose solution. Before gum chewing, and at 7 min and 15 min afterward, whole plaque, plaque fluid, and salivary samples were obtained and analyzed by micro-analytical techniques. Additional samples were collected and analyzed at 25 min (7 min after the sucrose rinse). Although the results confirmed the deposition of large amounts of calcium and phosphates in plaque seen in the previous study, only a small increase was seen in plaque-fluid-free calcium and phosphate before sucrose administration. This suggests that few of the mineral ions were mobilized under non-cariogenic conditions. However, 7 min after the sucrose rinsing, an increase in these concentrations was seen which, based on hydroxyapatite ion activity product calculations, indicated a decrease in the driving force for demineralization compared with that seen with the control gum. These results suggest that the chewing of the experimental gum deposits a labile mineral reservoir in plaque that can resist a subsequent cariogenic challenge.

Adult↗

PubMed2000

Effect in vitro acidification on plaque fluid composition with and without a NaF or a controlled-release fluoride rinse.

Plaque fluid ion concentration changes, especially fluoride, in response to the pH decrease associated with a cariogenic episode are important components of the caries process. A "controlled-release" (CR) fluoride rinse, based on the controlled release of fluoride in the presence of calcium, has been shown to form large fluoride reservoirs in resting plaque. In this study, the in vitro acid-induced release of fluoride, and other ions, was examined in 48-hour-fasted plaque fluid from subjects (n = 11) who received no rinse, or who used a 228-ppm CR or NaF fluoride rinse 1 hr before being sampled. After collection, the plaque was centrifuged to yield plaque fluid, acidified (0.1 microL of 0.5 mol/L HCl per milligram plaque), and then re-centrifuged before a second sample was obtained. Although previous studies indicated a higher plaque fluid fluoride after the new rinse relative to NaF, no statistically significant difference was observed here. Average fluoride release after acidification (average pH, 5.2) was statistically greater following the use of the CR rinse (153 micromol/L) compared with the NaF rinse (17 micromol/L). No fluoride release was seen in the no-rinse samples. The pH, free calcium, phosphate, acetate, propionate, and buffer capacity were not affected by the different amounts of fluoride deposited in the plaque. However, following acid addition, an increase in free calcium and phosphate was observed, which was also independent of the rinse. The large release of fluoride following acidification suggests that the new rinse may provide an improved cariostatic effect.

Acetates↗

PubMed2000

Remineralization effects of a two-solution fluoride mouthrinse: an in situ study.

Results from previous studies show that a two-solution fluoride (F) rinse is significantly more effective than a NaF rinse of the same F content of 250 microg/g (ppm) in remineralizing enamel and root lesions in an in vitro cyclic de- and remineralization model. In the present study, the two-solution rinse and two NaF rinses with F contents of 250 ppm and 1000 ppm were evaluated in an intra-oral remineralization model. Caries-like lesions were formed in the enamel of extracted human molars with the use of a pH 4 demineralizing solution. Thin sections of the enamel (approximately 120 microm) containing lesions were prepared, and the mineral contents of the lesions were assessed by quantitative microradiography. With the cut surfaces protected by nail varnish, 3 enamel specimens were mounted with wax in the lingual areas of a removable mandibular appliance. The study used a randomized, crossover design with seven subjects. In each of the 3 legs of the study, subjects wore the appliances continuously except when eating, drinking, and brushing their teeth. Twice daily (after breakfast and before bedtime), the subjects received a one-minute rinse with 20 mL of (1) 250-ppm-F NaF rinse, (2) 1000-ppm-F NaF rinse, or (3) 228-ppm-F two-solution F rinse. At the end of the 14-day experimental period, the sections were retrieved, and the mineral contents of the lesions were again assessed quantitatively. The results show that both the 1000-ppm-F NaF and 228-ppm-F two-solution rinses produced a greater (p < 0.05) remineralization than did the 250-ppm-F NaF rinse. The remineralization produced by the two-solution rinse was not statistically different (p > 0.05) from that produced by the NaF rinse with 4x the F content (1000 ppm F).

Analysis of Variance↗

PubMed1998

Composition of plaque and saliva following a sucrose challenge and use of an alpha-tricalcium-phosphate-containing chewing gum.

Calcium phosphate concentrations in plaque, plaque fluid, and saliva play an important role in caries prevention. In this study, we used a microanalytical technique to examine the anticaries potential of a 2.5% (mass fraction) alpha-tricalcium-phosphate-fortified experimental gum by measuring the pH, free and total calcium, and total phosphate in plaque fluid, whole plaque, and saliva, and centrifuged saliva from 14 subjects who (1) accumulated plaque for 48 hours, (2) fasted overnight, (3) rinsed for 1 min with sucrose, and (4) chewed a control or experimental gum for 15 min. From these data, the hydroxyapatite (HAp) ion activity products (IAP[HAp]) of saliva and plaque fluid were calculated as a measure of tooth mineral saturation. Results, compared with those of the control gum, show significant increases in pH and in free calcium and phosphate concentrations in plaque fluid and saliva when the experimental gum was chewed following sucrose ingestion. These increases result in a rise in fluid saturation with respect to tooth mineral that, for plaque fluid, nearly cancels the decrease seen with the control gum after the sucrose rinse. This suggests that the experimental gum may be more effective than a conventional gum in ameliorating the cariogenic effects of sucrose. Similar statistically significant increases were also seen in the total calcium content of the plaque fluid, centrifuged saliva, whole saliva, and whole plaque, and in the total phosphate of whole plaque and whole saliva. These results suggest that the deposition of a mineral reservoir in plaque and saliva by the experimental gum may help resist future cariogenic challenges.

Adult↗

PubMed1997

An in vitro diffusion model for the study of calcification of bovine pericardium tissue.

Bovine pericardium (BP) is extensively used for the production of heart valve bioprostheses. BP has excellent mechanical properties but a limited lifespan because of intrinsic subsurface calcification in vivo. In this study, the in vitro mineralization of BP was investigated by a novel diffusion cell model. In two sets of experiments, glutaraldehyde-treated BP membranes were placed between two compartments, both of which contained calcium phosphate solutions made by equilibration of octacalcium phosphate (Exp I) or dicalcium phosphate dihydrate (Exp II) in phosphoric acid. The movement of calcium (Ca), phosphate (P), and protons through the BP membrane was followed throughout the diffusion process. Histology, scanning electron microscopy, wet chemical analysis, and energy dispersive X-ray analyses provided good evidence of subsurface mineralization of BP that resembled in vivo mineral deposition. Energy dispersive x-ray microanalyses found a Ca/P heterogeneity of the early subsurface mineral that formed in the membrane. The use of a diffusion cell to model BP calcification under well-characterized conditions has led to in vitro mineralization that more closely matches that observed in vivo. The results suggest that this in vitro diffusion model can be used to study the mechanism of pathological mineralization. This model has the potential to provide rapid, inexpensive, basic information about the mineralization process.

Animals↗

PubMed1997

Choroid plexus papilloma and cysts in the Aicardi syndrome: case reports.

Two female infants with callosal agenesis, infantile spasms, chorioretinal lacunae, optic disc colobomas and cortical heterotopias were diagnosed with Aicardi syndrome. A choroid plexus papilloma was found in one patient, and choroid plexus cysts were found in the other. Choroid plexus lesions are common findings in the Aicardi syndrome and are discussed in this paper.

Agenesis of Corpus Callosum↗

PubMed1997

Changes in the permselectivity of human teeth during caries attack.

Previous studies have shown that enamel permselectivity can influence fluid composition within caries lesions during de- and remineralization. The permselectivity of human enamel, cementum, and dentin sections was examined, in a microwell model, by measurement of the membrane potential developed by KCl diffusion while the sections were immersed in solutions simulating resting (pH = 5.6) and cariogenic plaque fluid (pH = 4.8). In a second experiment, the effects of charged compounds (phytate and Zonyl-FSC) on the tooth permselectivity were examined. The average membrane potentials (+/- SD) in "resting plaque" solution were: sound enamel, 18.9 +/- 3.2 mV, n = 66; dentin, 0.9 +/- 9.2 mV, n = 59; and cementum, -0.8 +/- 8.2 mV, n = 42, with a positive sing indicating cation selectivity. The average membrane potentials became more negative in "cariogenic plaque" solution for all types of sections: sound enamel, 5.2 +/- 2.1 mV, n = 46; dentin, -8.1 +/- 7.4 mV, n = 45; and cementum, -14.3 +/- 8.0 mV, n = 34. In lesion enamel sections, the membrane potential was reduced from the non-lesion wells in both types of test solutions, while phytate treatment caused an increase of approximately 10 mV in potential (increased cation selectivity) in every enamel well in either "resting" or "cariogenic" solution. Treatment of enamel sections with Zonyl-FSC caused the membrane potential to become more negative in both test solutions, with many of the wells showing anion selectivity in the cariogenic "plaque-like" solution. However, the changes in enamel membrane potentials induced by Zonyl-FSC slowly increased toward the initial values after treatment, while the effects of the phytate pre-treatment persisted. Most dentin sections treated with phytate also showed an increase in potential after phytate treatment; however, Zonyl-FSC seemed to have little effect on the membrane potential of dentin. The results of this study suggest that modification of tooth permselectivity by surface-active agents may be a viable method of decreasing the rate of caries progression.

Dental Caries↗

PubMed1997

Increased overnight fluoride concentrations in saliva, plaque, and plaque fluid after a novel two-solution rinse.

Recent studies showed that salivary, plaque-fluid, and whole-plaque fluoride were significantly higher 120 min after subjects rinsed with a novel two-solution rinse than after they rinsed with a NaF rinse of the same fluoride concentration. In this study, the persistence of these increases was investigated overnight, a period of time that is more clinically relevant. Improved analytical techniques for the ultramicro determination of whole-plaque and plaque-fluid fluoride from the same sample are also described. Thirteen subjects abstained from toothbrushing for 48 hrs and rinsed for 1 min with a 12 mmol/L (228 ppm) NaF or the two-solution rinse before bedtime. Samples were then collected the following morning before breakfast: (1) Saliva samples were either clarified by centrifugation or acid-extracted with 1 mol/L HClO4; and (2) single-site molar plaque samples were centrifuged to obtain plaque fluid and/or extracted with 1 mol/L HClO4. Results showed that, compared with NaF, the two-solution rinse produced significantly higher fluoride concentrations in all samples: The concentration of fluoride in whole plaque and whole saliva following the new rinse exceeded concentrations found after the NaF rinse by factors of three and four, respectively, while in plaque fluid, the two-solution rinse produced about a two-fold increase over NaF values, which were near baseline levels. This increase, however, was only about 20% in centrifuged saliva. The increases in saliva and especially in plaque-fluid fluoride after the two-solution rinse indicate a greater remineralization potential, while the enhanced fluoride reservoirs found in plaque overnight after this rinse constitute a reserve that may release fluoride into the plaque fluid over an extended period of time.

Adult↗

PubMed1995

Intensive swimming: can it affect your patients' smiles?

Athletes who swim intensively, such as those who swim laps more than six hours a week, may develop unusual yellowish brown or dark brown stains on their teeth. The authors hypothesize that long-term contact of the teeth with swimming pool water, as well as the mixture of oral fluids with swimming pool water, leads to the formation of these deposits. The authors report two cases of development of such stains.

Adolescent↗

PubMed1994

Cyclic polyamine ionophore for use in a dibasic phosphate-selective electrode.

A cyclic polyamine, 3-decyl-1,5,8-triazacyclodecane-2,4-dione (N3-cyclic amine), was used as the ionophore for a dibasic phosphate-selective electrode. This electrode exhibited a linear response between 1.0 mumol/L and 0.1 mol/L dibasic phosphate activity with a near-Nernstian slope of approximately -29 mV per activity decade. The electrode selectivity for dibasic phosphate over other commonly occurring anions was evaluated. A mechanism for the selectivity of the electrode toward HOP4(2-) ions is postulated to be a function of the size and charge of the N3-cyclic amine ionophore relative to the size and charge of HPO4(2-) ions. The electrode's superior selectivity and sensitivity make possible the direct measurement of phosphate activity in a wide variety of applications.

Heterocyclic Compounds↗

PubMed1992

In vivo fluoride concentrations measured for two hours after a NaF or a novel two-solution rinse.

The concentrations of fluoride in various samples from the oral environment were measured at timed intervals after a novel rinse or a NaF rinse, both containing a total of 12 mmol/L (228 ppm) fluoride. The novel rinse consisted of two solutions mixed just before application: Part A contained calcium chloride and sodium acetate; part B contained a hydrolyzable source of fluoride (sodium hexafluorosilicate) and sodium phosphate. Samples were obtained as follows: Single-site plaque-fluid samples were obtained by centrifugation of first-molar plaque; pooled whole-plaque samples were collected from second molars; centrifuged, pooled whole-saliva was collected by vacuum. All samples were analyzed by micro-analytical methods. Results showed that, compared with NaF, the two-solution rinse produced significantly higher salivary fluoride concentrations, plaque-fluid fluoride concentrations, and acid-extractable fluoride in the whole plaque by factors of about 4, 2, and 6, respectively, at 120 min. The results of this study suggest that the new rinse may provide a greater cariostatic effect at the same fluoride dosage than does a NaF rinse.

Adult↗

PubMed1992

Distribution of fluoride in saliva and plaque fluid after a 0.048 mol/L NaF rinse.

An ultramicro method has recently been described for measurement of plaque-fluid fluoride concentration (Vogel et al., 1990a). This method was used: (1) for exploration of the variation in fluoride concentration of plaque fluid collected from the same buccal tooth sites following a 0.048 mol/L NaF (0.2%) rinse, and (2) for examination of the distribution of fluoride in plaque fluid and saliva within one hour after this rinse. Results indicated an average coefficient of variation (CV) of 31% for plaque-fluid fluoride in triplicate samples recovered simultaneously from the buccal-proximal region of two teeth after the rinse. This was similar to the CV found for plaque-fluid fluoride from the same sites after separate administrations of the rinse. A strong linear correlation was found between salivary and plaque-fluid fluoride at 30 and 60 min after rinse administration, showing that plaque-fluid fluoride is influenced by the concentration of salivary fluoride after administration of this rinse. Plaque-fluid fluoride concentrations were higher than that in saliva at baseline, 30, and 60 min. Very large inter-site and intersubject variations in plaque-fluid distribution were observed, with the central incisors showing the slowest clearance. These variations suggest that an examination of plaque-fluid fluoride from specific tooth regions may be essential for understanding the effects of fluoride on the site-specificity of caries.

Adult↗

PubMed1991

Echocardiographic left ventricular wall thickness: a poor predictor of the severity of aortic valve stenosis.

Echocardiographic left ventricular hypertrophy is thought to be helpful in grading the severity of aortic stenosis. This study compared M-mode echocardiographic left ventricular wall dimensions with Gorlin aortic valve area. Good quality echocardiograms were obtained in 294 patients with aortic stenosis who also underwent cardiac catheterization. Patients with grade 3 or 4 aortic regurgitation were excluded. The correlation was calculated between the aortic valve area and the left ventricular wall dimensions. Correlation coefficients were poor; r = 0.13 for the septum, r = 0.15 for the posterior wall, and r = 0.17 for the mean wall dimension. Correlation was not improved significantly if patients with poor left ventricular function or systemic hypertension were excluded. Correlation with other hemodynamic parameters was better, peak left ventricular systolic pressure having r values of 0.36 and 0.30 for posterior wall and septum. Mean and peak aortic valve gradient had r values approaching 0.30 for both dimensions. If the peak gradient was included in multivariate analysis, the wall dimensions then had no predictive power for severity of aortic stenosis. This study demonstrates that the degree of left ventricular wall hypertrophy is not related to the severity of aortic outflow obstruction and therefore cannot be used to grade the severity of aortic stenosis.

Aortic Valve↗