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Biomedical subjects

R M Browne

Publications and source records attributed to R M Browne.

At least 19 recordsLinked to original sources
PubMed1997

The use by general dental practitioners of an oral pathology diagnostic service over a 20-year period: the Birmingham Dental Hospital experience.

OBJECTIVE: To investigate the use of an oral pathology service by general dental practitioners over a 20-year period. DESIGN: Retrospective analysis of the number of cases received for histological examination in 1975, 1984 and 1994. SETTING: Birmingham Dental Hospital. SUBJECTS AND METHODS: 1101, 2395 and 3366 specimens were accessed respectively for the three years studied. Number and proportion of specimens received, number and proportion that were hard or soft tissue specimens and the information on the request form were recorded. A comparison was made between the provisional clinical and histological diagnoses. RESULTS: Although the number of specimens accessed increased approximately 3-fold, the number of specimens accessed from general dental practitioners increased 5-fold. The variety of histological categories increased by over 50%, most being soft tissue specimens. The number of correct provisional diagnoses increased steadily but the percentage with inappropriate provisional diagnoses remained the same. Information on request forms steadily improved. CONCLUSIONS: The increased number of specimens received from general dental practitioners over the 20-year period reflects an increased demand for an oral pathology diagnostic service. The referral pattern most likely indicates an increased awareness by general dental practitioners of the need to biopsy lesions arising within the oral cavity.

Biopsy↗
PubMed1997

Immunocytochemical expression of parathyroid hormone related protein (PTHrP) in odontogenic jaw cysts.

OBJECTIVE: To investigate the immunocytochemical expression of parathyroid-hormone-related protein (PTHrP) in odontogenic jaw cysts. DESIGN: Retrospective study of archival tissue. SETTING: University department, UK. MATERIAL: Odontogenic keratocysts (n=27), and dentigerous and radicular cysts (n=10 each). INTERVENTION: Immunocytochemistry by biotin streptavidin technique. MAIN OUTCOME MEASURE: Intensity of staining of PTHrP determined by TV image analysis. RESULTS: The epithelial linings of all the odontogenic keratocysts, 9/10 dentigerous, and 8/10 radicular cysts showed reactivity for PTHrP mainly localised to the basal and suprabasal layers. Odontogenic keratocyst linings expressed significantly higher levels of PTHrP than those of dentigerous and radicular cysts (P<0.003 in each case). There were no differences in epithelial expression of PTHrP between solitary, recurrent and naevoid basal cell carcinoma syndrome-associated odontogenic keratocysts. The fibrous tissue walls of all types of cyst reacted strongly for PTHrP with a trend towards decreasing intensity from odontogenic keratocysts, to dentigerous and then radicular cysts. CONCLUSION: It is possible that PTHrP modulates growth and bone resorption in odontogenic cysts. PTHrP may act synergistically with interleukin-1 to increase bone resorption or stimulate osteoblasts and inhibit osteoclasts (resulting in reduced resorption) via its transforming growth factor beta-like activity.

Analysis of Variance↗
PubMed1997

Immunocytochemical expression of growth factors by odontogenic jaw cysts.

AIM: To determine the immunocytochemical pattern of expression of transforming growth factor (TGF) alpha, epidermal growth factor (EGF), and TGF beta in the three most common types of odontogenic jaw cyst. METHODS: Growth factor expression was detected in paraffin wax sections of odontogenic cysts (27 odontogenic keratocysts, 10 dentigerous cysts, and 10 radicular cysts) using a streptavidin-biotin peroxidase technique with monoclonal antibodies directed against TGF alpha (clone 213-4.4) and TGF beta (clone TB21) and a polyclonal antibody directed against EGF (Z-12). RESULTS: The epithelial linings of all cysts showed reactivity for TGF alpha which was mainly localised to basal and suprabasal layers. Odontogenic keratocyst linings expressed higher levels of TGF alpha than those of dentigerous and radicular cysts, with 89% (24/27) of odontogenic keratocysts exhibiting a strong positive reaction compared with 50% (five of 10) of dentigerous and radicular cysts, respectively. EGF reactivity was similar in all cyst groups, weaker than that for TGF alpha and predominantly suprabasal. TGF alpha and EGF were also detected in endothelial cells, fibroblasts and inflammatory cells within the cyst walls. The most intense TGF beta staining in odontogenic cysts was extracellular within the fibrous tissue capsules, irrespective of cyst type. CONCLUSIONS: These results, together with previous studies of EGF receptor, indicate differential expression of TGF alpha, EGF and their common receptor between the different types of odontogenic cyst, suggesting that these growth factors (via autocrine or paracrine, or both, pathways) may be involved in their pathogenesis.

Dentigerous Cyst↗
PubMed1997

Survey of the use of personal protective equipment and prevalence of work related symptoms among dental staff.

OBJECTIVES: Dental instruments such as the right angle or straight handpiece, air turbine, and ultrasonic scaler have the ability to produce dental aerosols containing water, saliva, microorganisms, blood, tooth particles, lubricating oil, and restorative materials. The purpose of this study was to find out whether personal protective equipment (mask, glasses) was used by dental personnel, and to investigate possible work related disease in the dental profession. METHODS: Cross sectional data were collected with a self administered questionnaire sent to 69 randomly chosen general dental practices in the West Midlands Region. All members of the dental team completed questionnaires (dentists (n = 122); nurses (n = 115); hygienists (n = 86); and receptionists (n = 74) and answered questions on use of personal protective equipment and the prevalence of upper and lower respiratory tract, eye, and skin symptoms (reported and work related). Reception staff were included as a low exposure, control group. Also, a longitudinal study of dental hygienists was carried out on 31 people who had taken part in a similar study five years earlier. RESULTS: Use of a face mask and glasses differed between clinical groups with hygienists and nurses being the most and least prevalent users respectively. Although several reported symptoms were significantly more prevalent among clinical staff, only one work related symptom (skin rashes or itchy or dry skin) was reported by the clinical staff more than by the non-clinical receptionists. Among female clinical staff, age < 35 years and atopy were the factors that predisposed to work related symptoms. Also, reported symptoms were related to duration of use of instruments that generated aerosols. CONCLUSIONS: This study shows a low level of work related symptoms in dentistry, but highlights a group vulnerable to prolonged exposures to dental aerosols. It also supports the need for enforcement of the use of personal protective equipment among dental nurses.

Adolescent↗
PubMed1996

In vivo surface analysis of titanium and stainless steel miniplates and screws.

This study was undertaken to characterize the surfaces of Champy titanium and stainless steel miniplates and screws that had been used to stabilize fractures of the mandible in an animal model. Miniplates and screws were retrieved at 4, 12, and 24 weeks after surgery. Low-vacuum scanning electron microscopy (SEM) of autoclaved unused (control) and test miniplates from the same production batches was undertaken. Energy-dispersive X-ray (EDX) analysis was used to identify compositional variations of the miniplate surface, and Vickers hardness testing was performed. At autopsy, clinical healing of all fractures was noted. SEM analysis indicated no perceptible difference in the surface characteristics of the miniplates at all time intervals. Aluminium and silicon deposits were identified by EDX analysis over the flat surfaces. There was extensive damage to some screw heads. It is concluded that there were no significant changes in the surface characteristics of miniplates retrieved up to 24 weeks after implantation in comparison with controls. Damage to the screws during insertion due to softness of the materials may render their removal difficult. There was no evidence to support the routine removal of titanium or stainless steel miniplates because of surface corrosion up to 6 months after implantation.

Analysis of Variance↗
PubMed1996

p53 expression in odontogenic keratocyst epithelium.

The expression of p53 protein was studied in odontogenic keratocysts (OKC, 11 solitary, 5 recurrent and 6 NBCCS cysts), radicular (RC, n = 5) and dentigerous (DC, n = 5) cysts, using a panel of antibodies to p53 (clone BP53-12, clone 1801 and polyclonal CM1) and a sensitive biotin-streptavidin method on paraffin embedded sections. Of the three antibodies tested, clone BP53-12 gave the most intense and consistent nuclear staining pattern. Clone 1801 and polyclonal CM1 stained only 38% and 71% OKC linings, respectively, but not RC and DC linings. However, BP53-12+ cells were detected in the epithelial linings of all cyst types. Quantification of BP53-12+ cells was performed by manual counting and by relating cell number to unit length of basement membrane as determined by TV image analysis. BP53-12+ cell counts in solitary OKC linings (25.5 +/- 11.0 cells/mmBM) were significantly greater than those in DC (9.3 +/- 4.9 cells/mmBM, P < 0.01) and RC (6.7 +/- 2.6 cells/mmBM, P < 0.01) linings. The epithelial distribution of positive cells in OKC was predominantly suprabasal, which also varied from that of DC and RC linings (P < 0.005). There were no detectable differences in BP53-12 reactivity between the different subtypes of OKC (i.e., solitary, recurrent and NBCCS-associated OKC; P > 0.1). When data for the NBCCS-related OKC group were excluded, there was a significant correlation (r = 0.55, P < 0.01) between p53 and Ki67 labelling. To detect the presence of p53 gene mutations, genomic DNA, extracted from paraffin sections of OKC (4 solitary, 2 recurrent and 4 NBCCS cysts), RC (n = 3) and normal oral mucosa (n = 1), was subjected to a combination of polymerase chain reaction and single-stranded conformation polymorphism (PCR-SSCP) analysis for exons 5-10 of the p53 gene. Exon 4 was not analysed because of compromised DNA quality. No abnormality in banding patterns was found and all samples gave results similar to DNA from known, sequenced, normal p53 gene controls. Absence of p53 mutations within exons 5-9 was confirmed by the direct sequencing of 2 fresh frozen OKC samples (1 solitary and 1 NBCCS cyst). These results suggest that overexpression of p53 protein in OKC epithelium, detected by immunocytochemistry, is not reflected by alteration of the p53 gene and presumably reflects overproduction and/or stabilisation of normal p53 protein.

Antibodies↗
PubMed1995

Subperiosteal behaviour of alginate and cellulose wound dressing materials.

A histological comparison was undertaken of the tissue response to a new sodium calcium alginate material (Kaltostat) and an oxidized regenerated cellulose wound dressing (Surgicel) when implanted between bone and periosteum in the jaws at intervals of up to 24 wk. Both biomaterials caused a foreign body reaction, persisting up to 12 wk after surgery. New bone formation occurred along the surface of the mandible in some specimens, but was not apparently related to the implants. It was concluded that the implantation of Kaltostat or Surgicel between bone and periosteum in the jaws caused a delay in wound healing, and had no effect on bone induction.

Alginates↗
PubMed1995

Factors influencing the patterns of invasion of the mandible by oral squamous cell carcinoma.

The pattern of tumour invasion of the mandible depends on the extent of invasion. Both the width (P = 0.02) and depth (P = 0.01) in patients with an invasive or infiltrative pattern of disease were greater than in tumours showing the less aggressive erosive pattern in which the tumour mass is separated from the resorbing bone by a connective-tissue layer. Evidence in this study suggests that the erosive pattern develops through a mixed pattern to the invasive pattern of disease as the tumour progresses through the bone. The invasive pattern of disease was evident at a much shallower depth in the molar region of the mandible (mean 9 mm), with a decreased ratio of alveolar to basal bone, than in the premolar and parasymphyseal region (mean 25 mm) (P = 0.02). The hypothesis to explain this phenomenon is that the more superficial alveolar bone responds by resorbing in advance of the tumour, but the basal bone is unable to respond in the same way and becomes widely infiltrated. The attached mucosa with its firm collagen attachment to bone is proposed as the main route of tumour entry into the mandible in both dentate and edentulous mandibles.

Alveolar Process↗
PubMed1995

Glandular odontogenic cysts. Diagnosis and treatment.

Four cases of glandular odontogenic cyst are reported. Review of these and 13 previously reported cases indicates that they present as slowly growing, painless, radiolucent swellings with a predilection for the anterior part of the mandible. An incisional biopsy is essential to establish a definitive preoperative diagnosis. The unpredictable and potentially aggressive nature of these lesions is suggested by their extensive nature, penetration of cortical bone, locally invasive potential, and high incidence of recurrence after conservative treatment. In view of this behavior we suggest en bloc excision and primary reconstruction to ensure cure and reduce the operative morbidity.

Adult↗
PubMed1995

Expression of proliferating cell nuclear antigen (PCNA) and Ki-67 in unicystic ameloblastoma.

The expression of proliferating cell nuclear antigen (PCNA) and Ki-67 was studied in unicystic and solid ameloblastoma (follicular and plexiform types) using a biotin-streptavidin method on routinely processed paraffin sections. To determine percentage PCNA and Ki-67 labelling indices, positive tumour cells and total tumour cells were counted in areas of each unicystic ameloblastoma corresponding to cystic linings, intraluminal nodules and invading tumour islands, and in solid ameloblastomas. Positive cells in basal and suprabasal layers of cystic tumour lining were also counted with respect to the length of basement membrane determined by image analysis. In unicystic ameloblastoma the invading islands exhibited a significantly higher PCNA labelling index (29.2 +/- 16.4%) than intraluminal nodules (13.6 +/- 5.4%; P < 0.05). Cystic tumour lining had relatively few PCNA positive cells and a labelling index (5.5 +/- 3.3%) significantly lower than invading islands (P < 0.001) or intraluminal nodules (P < 0.003). The labelling indices of solid ameloblastomas of follicular type (48.1 +/- 12.9%) were significantly higher than those of cystic tumour lining (P < 0.0001), intraluminal nodules (P < 0.001) and invading islands (P < 0.04) in unicystic ameloblastoma. Similar relationships were found for Ki-67 expression except that comparisons involving invading islands and intraluminal nodules were not significant, a finding probably due to the smaller number of specimens available for quantitative analysis. These results indicate differences in proliferative potential between different areas of unicystic ameloblastoma and between unicystic and solid lesions. The fact that invading tumour islands within the fibrous tissue wall showed high labelling indices is in agreement with the clinical observation that their presence may be related to recurrence after conservative surgery. This provides a biological basis for indicating more radical surgical excision as the treatment of choice for this subgroup of lesions.

Ameloblastoma↗
PubMed1995

Epithelial cell proliferation in odontogenic keratocysts: a comparative immunocytochemical study of Ki67 in simple, recurrent and basal cell naevus syndrome (BCNS)-associated lesions.

The aim of the present study was to investigate epithelial cell proliferation in the linings of odontogenic cysts, including three different subtypes of odontogenic keratocyst (OKC), namely simple (non-recurrent), recurrent and basal cell naevus syndrome (BCNS)-associated lesions. Ki67 immunoreactivity in OKC (simple, n = 10; recurrent, n = 8; syndrome, n = 9), dentigerous cysts (DC, n = 5), radicular cysts (RC, n = 5) and normal oral mucosa (n = 7) was studied using a biotin-streptavidin-peroxidase method on paraffin sections after microwave treatment. Ki67+ epithelial cells were counted manually and related to the length of basement membrane (BM) as determined by TV image analysis. Data were analysed by the Mann-Whitney U test. The number of Ki67+ cells in simple OKC linings (53.1 +/- 17.8 cells/mmBM) was similar to that in oral epithelium (42.5 +/- 12.7 cells/mmBM; P > 0.2). However, both contained significantly more Ki67+ cells than DC (3.9 +/- 1.3 cells/mmBM) and RC linings (6.7 +/- 4.8 cells/mmBM; P < 0.006). The epithelial distribution of Ki67+ cells differed between groups, with the percentage of positive cells in basal layers in OKC linings (7.0 +/- 2.1%) being significantly lower than that of oral epithelia (35.9 +/- 5.6%), DC (78.4 +/- 8.4%) and RC (80.6 +/- 7.7%) linings respectively (P < 0.003). Comparison of Ki67 expression within the OKC group revealed no significant difference between simple and recurrent lesions (44.0 +/- 13.8 cells/mmBM; P > 0.3). However, OKC associated with BCNS contained significantly higher numbers of Ki67+ cells (91.8 +/- 35.6 cells/mmBM; P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1995

Parathyroid hormone related protein in oral squamous cell carcinomas invading the mandible.

AIM: To assess parathyroid hormone related protein (PTHrP) as a candidate biochemical marker of invasion of the mandible by oral squamous cell carcinoma. METHODS: Tumour PTHrP concentrations were quantitated by immunoassay, and PTHrP was detected by immunohistochemistry, in a cohort of 24 primary squamous cell carcinomas of the mandible. RESULTS: PTHrP was identified in all tumours examined, but no correlation was found between scores of the intensity and/or consistency of staining or tumour PTHrP concentrations and the histological classification of tumour invasion. CONCLUSION: Although PTHrP was present in all squamous tumours studied, there was no correlation between PTHrP expression and pattern of tumour invasion. However, tumour derived PTHrP may act locally to influence tumour growth and differentiation and resorption of bone.

Biomarkers, Tumor↗
PubMed1995

The biological evaluation of medical devices used in dentistry. The influence of the European Union on the preclinical screening of dental materials.

The advent of the European Union requires the biological evaluation of all medical devices used in dentistry prior to their general availability for clinical use. Biological evaluation is one component of the 'Essential Requirements' with which all devices need to conform. Such conformity will result in the issue of the CE mark. To facilitate this process, harmonised European standards are required. It is the policy of The European Committee for Standardisation (CEN) that, whenever possible, the relevant International standards will be adopted as European standards.

Animals↗
PubMed1995

Mast cells in laser and surgical wounds.

Precooling of tissues was investigated as a possible means of reducing thermal damage during CO2 laser surgery of the oral mucosa. The changes in mast cells in scalpel, and in non-cooled and precooled (tissue temperature lowered to approximately 10 degrees C) CO2 laser wounds were studied. Standard wounds five mm in length were created with the CO2 laser or scalpel on the dorsum of the tongues of 32 Sprague-Dawley rats under general anesthesia with fentanyl/fluanisone and midazolam. Animals were killed with excess anesthetic immediately or six hours after surgery, their tongues were removed, trimmed, fixed in neutral formalin and processed to paraffin wax. Acid (pH 1.4) toluidine blue stained sections were used to count normal and degranulated mast cells in five fields (0.1 mm2) located at defined positions immediately adjacent to the wound site. At both 0 and 6 hours normal mast cell numbers were significantly different between treatment groups (P<0.045; ANOVA) with mean numbers highest in scalpel wounds and lowest in uncooled laser wounds. Similarly, at 0 time, there were significant differences in degranulated mast cells between treatment groups (P=0.004; ANOVA) but highest numbers were detected in uncooled laser wounds and lowest in scalpel wounds. There were no significant differences in degranulated mast cell counts at six hours although there was a similar distribution in numbers between groups. Total numbers of mast cells (normal + degranulated) did not differ between treatment groups. These results demonstrated that i) laser wounds are associated with greater levels of mast cell degranulation than scalpel wounds and ii) precooling of tissues prior to laser treatment decreases the level of mast cell degranulation. It is concluded that tissue damage in CO2 laser surgery may be reduced by precooling of tissue.

Analysis of Variance↗
PubMed1994

Odontoblast stimulation in ferrets by dentine matrix components.

The possible effects of isolated dentine matrix components on odontoblast secretory activity were investigated in vivo by implantation of lyophilized fractions of these components into cavities prepared in ferret canine teeth. After implantations as short as 14 days there was significant deposition of reactionary dentine by the odontoblasts beneath the cavity and this response increased in a non-linear manner with time of implantation. In contrast, control cavities lacking the dentine matrix components showed no evidence of reactionary dentine deposition. Examination of teeth at early periods of implantation (2 and 5 days) indicated that odontoblast death had not occurred as a result of the operative procedures and that the response was one of stimulation of existing odontoblasts rather than that of induction of a new generation of odontoblast-like cells. The mechanisms of odontoblast stimulation by the dentine matrix components remain to be elucidated, but could be mediated by growth factors within the dentine matrix preparations.

Animals↗
PubMed1994

Alginate fiber dressing for oral mucosal wounds.

The aim of this study was to evaluate the effect on hemostasis and wound healing of a proprietary alginate fiber dressing when applied to a wound of the buccal mucosa of approximately 2 mm depth. The study showed a significant reduction in the number of residual bleeding points in shallow wounds when the alginate fiber dressing was applied for 5 minutes as compared with the use of non-alginate-impregnated surgical gauze. There was no significant difference in the rate of epithelial repair of the test and control sites nor in the area of the resulting mucosal scar. In addition, there was no significant difference in the numbers of tissue components in the submucosa. It is concluded that the alginate fiber dressing material evaluated in this study may be effective as a hemostatic mucosal dressing in shallow wounds, but it does not accelerate mucosal wound healing.

Alginates↗