Biomedical subjects

A J Smith

Publications and source records attributed to A J Smith.

At least 55 records · Page 3Linked to original sources

PubMed2003

Reduction in visceral slide is a good sign of underlying postoperative viscero-parietal adhesions in children.

BACKGROUND/PURPOSE: Viscera stuck to the anterior abdominal wall from previous surgery risk injury during laparoscopic surgery. A prospective study was conducted to determine if these adhesions are detectable on ultrasound scan by showing a reduction in the normal visceral slide. METHODS: Patients undergoing laparoscopic procedure after a previous laparotomy underwent preoperative real-time ultrasound scan to observe if viscera slides freely under the abdominal wall. A reduction in slide was considered a positive sign of underlying adhesions. These findings were correlated with the operative findings. RESULTS: Anterior abdominal wall scans were performed on 17 children. Reduced visceral slide was seen in 10. Viscero-parietal adhesions were found in 9 of 10 patients. Visceral slide was reduced in a very localized area in 6 patients, and, in these, a loop of bowel (n = 3), liver and bowel (n = 2), or liver (n = 1) was adherent. In 4, reduced visceral slide was seen over a wide area. Extensive adhesions were found in 3 of 4. One renal transplant patient with peritonitis had a false-positive ultrasound scan. At laparotomy there were no adhesions. The peritonitis is thought to have prevented an adequate examination. Seven patients had normal visceral slide. Of these, 4 had no adhesions, but 3 children had flimsy omental adhesions. The sensitivity and specificity of visceral slide in predicting adhesions were 75% and 80%, respectively. CONCLUSIONS: Reduction in visceral slide is a good sign of underlying postoperative viscero-parietal adhesions. Ultrasonographic mapping of the abdominal wall may be useful in selecting an adhesion-free site for trocar insertion in children with previous operations requiring laparoscopic procedures.

Abdominal Wall↗

PubMed2003

The influence of fluoride on the cellular morphology and synthetic activity of the rat dentine-pulp complex in vitro.

Exposure to high fluoride concentrations in the immediate environment of the tissue is recognized to result in the post-translational modification of non-collagenous dentine extracellular matrix (ECM) components, potentially altering dentine mineralization. However, less is known about the effects of fluoride exposure on the morphology or metabolism of the cells associated with the dentine-pulp complex. This study examined the effects of fluoride exposure at defined concentrations on the cellular morphology and ECM synthetic activities of odontoblasts and pulpal fibroblasts by the culture of tooth sections from male Wistar rat incisors in Trowel-type cultures for up to 14 days, in the presence and absence of 6mM sodium fluoride. Histomorphometric analysis of the dentine-pulp complex of sodium fluoride-exposed tooth sections demonstrated no obvious gross morphological differences with respect to the odontoblasts and pulpal fibroblasts throughout the 14-day culture period, in comparison with unexposed tooth sections. No significant differences in odontoblast and pulpal fibroblast cell numbers were determined in the absence and presence of fluoride. Image analysis examination of odontoblast cytoplasmic:nuclear (C/N) ratios also showed no significant differences in fluoride-exposed and unexposed tooth sections, although reductions in the C/N ratios of pulpal fibroblasts were evident in fluoride-exposed sections at days 10 and 14. No significant differences in predentine width were observed in fluoride-exposed and unexposed tooth sections over the 14-day culture period. Autoradiography following [3H]proline incorporation into the dentine-pulp complex demonstrated inhibition of collagen synthesis, particularly by the odontoblasts in tooth sections exposed to 6mM sodium fluoride. These findings, in association with those from previous studies, imply that dentine ECM alterations may contribute to the altered mineralization of dentine during fluorosis, rather than secretory-related changes in odontoblast morphology.

Animals↗

PubMed2003

Odontoblast morphology and dental repair.

OBJECTIVES: To investigate the changes in morphology and activity of pulp odontoblasts in response to cavity restoration variables and patient factors. METHODS: Class V non exposed cavities were prepared in the intact 1st or 2nd premolar teeth of 27 patients, aged between 9 and 17 years-old. Following tooth extraction, the area of reactionary dentine and the area of the odontoblasts were measured using computerised histomorphometry. RESULTS: The cytoplasm to nucleus ratio of the odontoblasts was found to increase beneath cut dentinal tubules, following the secretion of reactionary dentine. However, none of the patient or preparation variables were found to be correlated with changes in the odontoblast cytoplasm to nucleus ratio. CONCLUSIONS: Morphological changes in human odontoblasts is directly related to their capacity to repair dentine injuries and provide pulp protection. Changes in odontoblast morphology reflect secretory activity.

Adolescent↗

PubMed2003

Mild dehydration: a risk factor for dental disease?

A review of the published international literature was undertaken to investigate whether dehydration is a risk factor for dental disease. Published evidence of associations between saliva and dental disease and between saliva and dehydration was observed, but the precise nature of these associations is unclear and no evidence of a direct link between dehydration and dental disease was found. It is concluded that no direct link between dehydration and dental disease has been proven, although there is considerable circumstantial evidence to indicate that such a link exists.

Dehydration↗

PubMed2003

Intraocular gene delivery of ciliary neurotrophic factor results in significant loss of retinal function in normal mice and in the Prph2Rd2/Rd2 model of retinal degeneration.

Intraocular delivery of a variety of neurotrophic factors has been widely investigated as a potential treatment for retinal dystrophy (RD). The most commonly studied factor, ciliary neurotrophic factor (CNTF), has been shown to preserve retinal morphology and to promote cell survival in a variety of models of RD. In order to evaluate CNTF as a potential treatment for RD, we used the Prph2(Rd2/Rd2) mouse. CNTF was expressed intraocularly using AAV-mediated gene delivery either by itself or, in a second treatment group, combined with AAV-mediated gene replacement therapy of peripherin2, which we have previously shown to improve photoreceptor structure and function. We confirmed in both groups of animals that CNTF reduces the loss of photoreceptor cells. Visual function, however, as assessed over a time course by electroretinography (ERG), was significantly reduced compared with untreated controls. Furthermore, CNTF gene expression negated the effects on function of gene replacement therapy. In order to test whether this deleterious effect is only seen when degenerating retina is treated, we recorded ERGs from wild-type mice following intraocular injection of AAV expressing CNTF. Here a marked deleterious effect was noted, in which the b-wave amplitude was reduced by at least 50%. Our results demonstrate that intraocular CNTF gene delivery may have a deleterious effect on the retina and caution against its application in clinical trials.

Animals↗

PubMed2003

Remaining dentine thickness and human pulp responses.

AIM: To evaluate pulp responses as a function of remaining dentine thickness (RDT) of 98 class V cavity preparations in 49 teeth of 31 patients aged 10-16 years. METHODOLOGY: Shallow cavities were restored with amalgam, deeper cavities or pulp exposures were restored with amalgam lined with calcium hydroxide or with zinc oxide eugenol. Teeth were extracted after 3-89 days for orthodontic reasons. Following processing for light microscope analysis, the number of odontoblasts, pulp inflammation, and repair was recorded. RESULTS: In comparison with independent odontoblasts, the numbers of odontoblasts were reduced by 13.6% beneath a RDT of 2.5-0.5 mm, 33.7% beneath a RDT of 0.5-0.01 mm and 99.0% beneath pulp-exposed cavities. Reparative dentine was observed following pulp exposure and reactionary dentine was observed with a mean RDT of 0.77 mm (2.5-0.01 mm). Reactionary dentine secretion was influenced by RDT and restorative materials. Pulp inflammation was not influenced by RDT in the present study. CONCLUSIONS: Cavity RDT mediates a powerful influence on underlying pulp tissue vitality but it has little effect on reactionary dentine secretion and inflammatory activity. Gross tissue injury explains the poor pulp capping prognosis following exposure and underlies the need to avoid this type of injury. Following restoration, a RDT of 0.5 mm or greater is necessary to avoid evidence of pulp injury.

Adolescent↗

PubMed2003

A randomized controlled trial of a brief intervention after alcohol-related facial injury.

AIM: To evaluate the effectiveness of a brief motivational intervention on alcohol consumption and misuse in young males with alcohol-related face injury. DESIGN: Randomized controlled trial. SETTING: Oral and maxillofacial surgery out-patient clinic in an urban teaching hospital. PARTICIPANTS: One hundred and fifty-one participants were randomized to motivational intervention and control conditions. INTERVENTIONS: Control was treatment as usual. The intervention was treatment as usual plus a one-session brief motivational intervention administered by a nurse. MEASUREMENTS: Three sets of measurements were taken at baseline, 3-month and 1-year follow-up. Collateral measurements were also taken at 1-year follow-up. Primary outcome measures were total alcohol consumption, typical weeks consumption and days abstinent in preceding 3 months. Other outcome measures included the Alcohol Use Disorders Identification Test, a short form of the Alcohol Problems Questionnaire, and a measure of satisfaction with social relationships. RESULTS: There was a significant decrease in 84-day total alcohol consumption across the year (P < 0.006) and further, a significant effect for the motivational intervention was demonstrated (P < 0.029). This pattern was repeated for days abstinent and alcohol consumption in a typical week as well as alcohol-related problems. There was a significantly greater reduction in the percentage of hazardous drinkers in the motivational intervention group (from 60% to 27%, P < 0.009) compared to the control group (from 54% to 51%, NS). CONCLUSION: A proportion of young men change their alcohol consumption following alcohol-related injury. A nurse-led psychological intervention adds significantly to the proportion and magnitude of response.

Adolescent↗

PubMed2003

Histomorphometric analysis of odontoblast-like cell numbers and dentine bridge secretory activity following pulp exposure.

AIM: The purpose of this study was to collect quantitative information about the numbers and dentine bridge secretory activity of odontoblast-like cells following dental pulp exposure. METHODOLOGY: The numbers and secretory activity of odontoblast-like cells were measured histomorphometrically between 7 days and 2 years in 161 pulp-exposed nonhuman primate teeth. The area of dentine bridges and the dimensions of cavity preparations were measured. The density of odontoblast-like cells and subjacent reorganizing tissue cells were measured beneath dentine bridge formation. The presence of operative dentine debris and tunnel defects in bridges was noted. Pulp inflammation was categorized according to ISO standards. Bacteria were detected using McKay's stain. RESULTS: The area of dentine bridges was mediated by the density and secretory activity of odontoblast-like cells over time. The cell density of subjacent reorganizing tissue was found to be strongly associated with that of odontoblast-like cells. Bacterial microleakage was found to impede dentine bridge secretion by odontoblast-like cells. CONCLUSIONS: Pulp reparative activity occurs naturally beneath capping materials in the absence of bacterial microleakage. The outcome of pulp-capping treatments could be beneficially influenced by concentrating attention on limiting the width of pulp exposure, minimizing pulp injury by limiting the creation of operative debris and placing materials which prevent bacterial microleakage.

Analysis of Variance↗

PubMed2003

Prions and the oral cavity.

Prion diseases have recently emerged as a significant challenge to health-care workers, including those involved in dentistry. Abnormal prion proteins are resistant to complete inactivation by conventional sterilization techniques. In the last decade, a new form of prion disease emerged in the UK, termed "variant CJD", thought to be acquired by consumption of bovine spongiform encephalopathy-contaminated food products. At present, CJD is an invariably fatal disease with no immediate prospect of treatment or vaccination. Of concern with the variant form of CJD, unlike the more classic forms of the disease, is the appearance of significant levels of infectivity outside the central nervous system. This raises concerns for the potential transmission of prion proteins via surgical procedures from individuals in the asymptomatic stage of the disease. This article reviews the existing knowledge base on the nature of prions, their distribution in oral tissues, and the implications for dental treatment.

Animals↗

PubMed2003

Lymph node retrieval and assessment in stage II colorectal cancer: a population-based study.

BACKGROUND: Adjuvant chemotherapy for patients with stage III (node-positive) colorectal cancer (CRC) reduces mortality by one third. Retrieval of an inadequate number of lymph nodes in the surgical specimen may result in incorrectly designating some patients as stage II (node negative), and consequently, such patients may not be offered appropriate chemotherapy. Recent National Cancer Institute guidelines suggest that a minimum of 12 nodes should be examined to ensure accurate staging. METHODS: This population-based study identified stage II (T3N0 and T4N0) CRC cases by using CRC pathology reports (1997-2000) from the Ontario Cancer Registry. Patients aged 19 to 75 years were identified, and demographic, surgical, pathologic, and hospital data were extracted. Factors relating to the number of lymph nodes assessed were examined. RESULTS: A total of 8848 CRC cases were reviewed, and 1789 stage II cases were identified. Seventy-three percent of cases were designated as node negative on the basis of assessment of <12 lymph nodes. Multivariate analysis showed that age, tumor size, specimen length, use of a pathology template, and academic status of the hospital were significant predictors of the number of lymph nodes assessed. CONCLUSIONS: A subset of patients with CRC in Ontario were assigned stage II disease on the basis of examination of relatively few lymph nodes.

Adult↗

PubMed2002

A cross sectional study of water quality from dental unit water lines in dental practices in the West of Scotland.

OBJECTIVE: To determine the microbiological quality of water from dental units in a general practice setting and current practice for disinfection of units. DESIGN: A cross-sectional study of the water quality from 40 dental units in 39 general practices and a questionnaire of the disinfection protocols used in those practices. SETTING: NHS practices in primarydental care. SUBJECTS: Thirty-nine general practices from the West of Scotland. METHODS: Water samples were collected on two separate occasions from dental units and analysed for microbiological quality by the total viable count (TVC) method. Water specimens were collected from the triple syringe, high speed outlet, cup filler and surgery tap. Each participating practitioner was asked to complete a questionnaire. Results Microbial contamination was highest from the high speed outlet followed by the triple syringe and cup filler. On average, the TVC counts from the high speed water lines at 37 degrees C and for the high speed lines, triple syringe and cup filler at 22 degrees C were significantly higher than that from the control tap water specimens. The study included units from 11 different manufacturers with ages ranging from under one year to over eight years. The age of the dental unit analysed did not appear to influence the level of microbial contamination. Five of the practices surveyed used disinfectants to clean the dental units but these had no significant effect on the microbiological quality of the water. The majority of dental units (25 out of 40) were never flushed with water between patients. A number of different non-sterile irrigants were used for surgical procedures. CONCLUSION: The microbiological quality of water from dental units in general dental practice is poor compared with that from drinking water sources. Suitable sterile irrigants should be used for surgical procedures in dental practice. Further work is required for pragmatic decontamination regimens of dental unit water lines in a general dental practice setting

Colony Count, Microbial↗

PubMed2002

Evaluation of the efficacy of Alpron disinfectant for dental unit water lines.

AIMS: To assess the efficacy of a disinfectant, Alpron, for controlling microbial contamination within dental unit water lines. METHODS: The microbiological quality of water emerging from the triple syringe, high speed handpiece, cup filler and surgery hand wash basin from six dental units was assessed for microbiological total viable counts at 22 degrees C and 37 degrees C before and after treatment with Alpron solutions. RESULTS: The study found that the use of Alpron disinfectant solutions could reduce microbial counts in dental unit water lines to similar levels for drinking water. This effect was maintained in all units for up to six weeks following one course of treatment. In four out of six units the low microbial counts were maintained for 13 weeks. CONCLUSIONS: Disinfectants may have a short term role to play in controlling microbial contamination of dental unit water lines to drinking water quality. However, in the longer term attention must be paid to redesigning dental units to discourage the build up of microbial biofilms.

Amines↗

PubMed2002

Dental erosion in a group of British 14-year-old, school children. Part III: Influence of oral hygiene practises.

OBJECTIVES: The aims of this study were firstly to describe the dental history and oral hygiene practises in a cluster random sample of 14-year-old children in Birmingham, UK. The second aim was to determine whether the oral hygiene practises are associated with dental erosion. METHOD: A total of 418, 14-year-old schoolchildren from a cluster random sample in Birmingham, UK were assessed for dental erosion (209 males and 209 females). Data on the dental history and oral hygiene practises were obtained from a self-reported questionnaire supplemented by a structured interview. The data were analysed using SPSS with Mann-Whitney U analyses and odds ratios. RESULTS: 74% of the teenagers claimed to attend the dentist on a six-monthly basis; 60% brushed their teeth twice a day ie before breakfast and last thing at night, 25% once a day, 12% three times or more a day and 3% less than once a day. It was a so found that 28% of the children brushed their teeth after meals; 92% of the children used a manual toothbrush and 56% of them replaced their toothbrush every three-months. The most common technique used by the children was a circular brushing movement; 44% of them used a mouthwash and 40% used other interdental cleaning. Girls brushed their teeth more frequently than boys. Associations were found between dental erosion and brushing teeth last thing at night, after meals, techniques of brushing teeth, and type of toothbrush and frequency of brushing. It was concluded that reported oral hygiene practises in teenage schoolchildren in Birmingham, UK complied with generally recommended guidelines. However, there was an association between dental erosion and some of these oral hygiene practises. Advice concerning the impact of some oral hygiene procedures needs to be given to those who are susceptible to dental erosion.

Adolescent↗

PubMed2002

Ex vivo sentinel lymph node biopsy in colorectal cancer: a feasibility study.

BACKGROUND AND OBJECTIVES: Sentinel lymph node (SLN) biopsy may improve staging of colorectal cancer. We tested the feasibility of ex vivo SLN dissection. MATERIALS AND METHODS: Patients undergoing resection of a primary colorectal cancer were included in this study. SLN identification involved ex vivo injection of 1 cc isosulfan blue dye subserosally in the colon or submucosally in the rectum on a separate field. SLNs were cut at 2 mm intervals. Three hematoxylin and eosin-stained (HE) sections were prepared in addition to a middle level for cytokeratin immunostaining. RESULTS: Twenty-six patients with varying tumor location and stage were enrolled and the SLN was identified in 88% (23/26) cases. Three failures occurred in patients with rectal cancer. The average number of SLN harvested was 2.5. The status of the nodal basin was accurately predicted in 91% (21/23) of patients. Two false negative sentinel lymph nodes were harvested in 2 of 3 patients with stage III/IV colorectal cancer. The SLN upstaged 2 patients as a result of HE stained step sections (n = 1) and immunostaining (n = 1). CONCLUSIONS: This data suggests that ex vivo SLN biopsy is feasible in colorectal cancer. Although ex vivo SLN biopsy does not alter the lymphatic dissection, it may upstage a subset of patients. The ex vivo technique may be less applicable in rectal cancer and false negative results may occur.

Colonic Neoplasms↗

PubMed2002

Analysis of incisor pulp cell populations in Wistar rats of different ages.

Pulp cell function and viability is important for maintaining tooth vitality throughout life. However, the effects of ageing on pulpal cell populations and pulp tissue remodelling are still unclear. The aim here was to quantify age-related cell-density changes in the pulp of rat incisor teeth, using histomorphometric analysis and ANOVA. Mandibular (n=35) and maxillary (n=34) incisors were carefully extracted from 20 Wistar rats aged between 1 and 18 months, fixed and processed for light microscopy. Cell counts were performed in mature and immature regions at both labial and lingual aspects of all teeth. Odontoblast and subodontoblast cell densities were reported per mm of pulp-dentine border and core fibroblast density per mm2 pulp tissue. Irrespective of age, odontoblast and subodontoblast densities were lower in the immature than the mature regions of both maxillary and mandibular incisors (P<0.001). However, in both regions odontoblast and subodontoblast densities decreased significantly with increasing age (P<0.0001). The age-related reduction in odontoblasts was significantly greater in mature than immature regions (P<0.02) but not influenced by other variables. In contrast, the age-related reduction in subodontoblasts was significantly different between mandibular and maxillary teeth (P=0.012) but not influenced by site. Unlike odontoblasts and subodontoblasts, core fibroblasts showed small but significant increases with increasing age (P<0.0001). These age-related reductions in the density of odontoblasts and subodontoblasts may partly explain the slower rate of secondary dentine secretion and decreased pulp repair activity associated with ageing.

Aging↗

PubMed2002

Is there a relationship between asthma and dental erosion? A case control study.

OBJECTIVES: The aims of this study were firstly to assess and compare the prevalence of dental erosion and dietary intake between three groups of children; children with asthma, those with significant tooth erosion but with no history of asthma, and children with no history of asthma or other medical problems. Secondly, to discover whether there was a relationship between medical history and dietary practises of these children and the levels of dental erosion. Thirdly, to measure and compare their salivary flow rates, pH and buffering capacity. METHODS: The study consisted of 3 groups of children aged 11-18 years attending Birmingham Dental Hospital: 20 children with asthma requiring long-term medication, 20 children referred with dental erosion, and 20 children in the age and sex matched control group. Tooth wear was recorded using a modification of the tooth wear index (TWI) of Smith and Knight. Data on the medical and dietary history were obtained from a self-reported questionnaire supplemented by a structured interview. The salivary samples were collected under standard methods for measurements. RESULTS: Fifty percent of the children in the control group had low erosion and 50% moderate erosion. However, high levels were recorded in 35% of children in the asthma group and 65% in the erosion group. There appeared to be no overall differences in diet between the groups. There was an association between dental erosion and the consumption of soft drinks, carbonated beverages and fresh fruits in all the three groups. More variables related to erosion were found in the erosion and asthma groups. A comparison between the three groups showed no significant differences in unstimulated and stimulated salivary flow rates, or pH and buffering capacity. CONCLUSION: There were significant differences in the prevalence of erosion between the three groups, children with asthma having a higher prevalence than the control group. Although there was a relationship between the levels of erosion and some medical history and acidic dietary components, these did not explain the higher levels in asthmatic children. Further investigation is required into the factors affecting the increased prevalence of erosion in children with asthma.

Adolescent↗

PubMed2002

Isolation and characterization of a mutant strain of Streptococcus uberis, which fails to utilize a plasmin derived beta-casein peptide for the acquisition of methionine.

AIMS: To isolate and characterize a mutant of Streptococcus uberis strain 0140J which fails to utilize a plasmin derived beta-casein peptide for the acquisition of methionine. METHODS AND RESULTS: Random insertional mutagenesis was used to isolate a mutant strain of Strep. uberis 0140J which was unable to utilize methionine from within a casein-derived peptide. The altered gene in the mutant strain showed homology to an oligopeptide permease gene of Streptococcus pyogenes (oppF). The mutant was unable to obtain specific amino acids from defined peptides of various lengths and its growth yield in skimmed milk was between 1 and 10% that of the wild-type strain, but was restored following the inclusion of these amino acids. CONCLUSIONS: The oligopeptide permease homologue of Strep. uberis 0140J is necessary for the utilization of amino acids from within specific peptides. Efficient acquisition of essential amino acids by Strep. uberis 0140J is required for the bacterium to achieve an optimum yield in milk. SIGNIFICANCE AND IMPACT OF THE STUDY: Streptococcus uberis is a major agent of bovine mastitis with a corresponding high economic loss. By targeting metabolic pathways essential to the growth of Strep. uberis it may be possible to prevent the establishment of growth of the bacterium in milk. This study has identified the acquisition of essential amino acids as playing a role in the growth of Strep. uberis in milk.

Animals↗

PubMed2002

Effects of alginate hydrogels and TGF-beta 1 on human dental pulp repair in vitro.

The objective of this study was to investigate the use of alginate hydrogels to present either exogenous or endogenous transforming growth factor (TGF)-beta 1 to the dentin-pulp complex to signal reparative processes. Hydrogels were prepared, applied to cultured human tooth slices and the effects on tertiary dentinogenesis examined histologically. Both TGF-beta 1-containing and acid-treated alginate hydrogels, but not untreated hydrogels, upregulated dentin matrix secretion and induced odontoblast-like cell differentiation with subsequent secretion of regular tubular dentin matrix on cut pulpal surfaces. It is concluded that TGF-beta 1 can signal both induction of odontoblast-like cell differentiation and upregulation of their matrix secretion in the human dentin-pulp complex. Alginate hydrogels provide an appropriate matrix in which dental regeneration can take place and may also be useful for delivery of growth factors, including TGF-beta s, to enhance the natural regenerative capacity of the dental pulp.

Acids↗