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Biomedical subjects

R M Browne

Publications and source records attributed to R M Browne.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1994

A comparison of different imaging modalities and direct inspection after periosteal stripping in predicting the invasion of the mandible by oral squamous cell carcinoma.

OBJECTIVE: To compare the predictability of orthopantomograms (OPG), bone scans, computerised tomography (CT), magnetic resonance imaging (MRI) and periosteal stripping with direct inspection in predicting both the presence and extent of tumor invasion of the mandible. DESIGN: Prospective study. SETTING: Queen Elizabeth Hospital, Birmingham; Wordsley Hospital, Stourbridge; North Staffordshire Royal Infirmary, Stroke-on-Trent. SUBJECTS: 35 consecutive patients requiring a mandibular resection as part of their treatment for oral squamous cell carcinoma. MAIN OUTCOME MEASURES: The prediction of the extent of bone invasion for each of the investigations and direct inspection after periosteal stripping. The actual extent of invasion of the mandible from a detailed histological assessment. RESULTS: The OPG underpredicted the width and depth of invasion by on average 13 mm and 2 mm. There were 5 false negative reports. Bone scans overpredicted the width and depth by 14 mm and 15 mm with 1 false negative. CT scans underpredicted the width of invasion by 5 mm and overpredicted depth by 3 mm, but 7 false negatives were returned. MRI scans overpredicted width and depth of invasion by 19 mm and 10 mm with 1 false negative. Direct inspection after periosteal stripping underpredicted the width and depth of invasion by 5 mm and 3 mm with 1 false negative. CONCLUSION: OPG's and bone scans are useful for the initial assessment of all tumours in the region of the mandible. MRI is a more useful investigation than CT in the assessment of mandibular invasion by oral squamous cell carcinomas. Exploratory periosteal stripping at the time of resection can accurately predict the presence of tumour invading the mandible.

Adult↗
PubMed1994

Animal tests for biocompatibility of dental materials--relevance, advantages and limitations.

Biocompatibility refers to the ability of a material to perform with an appropriate host response, in a specific application. Usage tests have been developed specifically for the evaluation of the biocompatibility of dental materials. The pulp and dentine test, the pulpotomy test and the endodontic usage test are widely recognized. The relevance, advantages and limitations of these tests are discussed with particular reference to the pulp and dentine usage test. Controversies remain in the understanding of the role of several variables in determining the outcome of this test. These are highlighted by reference to the significance of the residual dentine thickness, the smear layer and microbial microleakage at the material-cavity wall interface. Limitations in the relevance of these animal models to man due to species variations in the structure and composition of the dental tissues and their oral environment may be more perceived than real. The nature of an appropriate host response may be different in the consideration of different dental materials, for example lining materials and filling materials, and there is a need for these criteria to be reviewed.

Animal Population Groups↗
PubMed1994

Quantification of PCNA+ cells within odontogenic jaw cyst epithelium.

The aim of this study was to investigate the reactivity of the epithelial linings of the three major types of odontogenic cyst with a monoclonal antibody to proliferating cell nuclear antigen (PCNA; clone PC10). PCNA expression was studied in odontogenic cysts (n = 31) and normal oral epithelium (n = 10) using a biotin-streptavidin method on routinely processed paraffin sections. PCNA+ cells were counted manually and related to the length of basement membrane (mm) and the epithelial area (mm2) as determined by TV image analysis. The epithelial linings of odontogenic keratocysts (OKC; n = 11) contained the highest number of PCNA+ cells, most of which were located in the suprabasal layers. The mean value of PCNA+ cells in OKC linings (94.4 +/- 22.7 cells/mm) was similar to that of oral epithelia (80.8 +/- 20.6 cells/mm), but both were significantly higher than that of dentigerous (n = 10, 5.1 +/- 3.0 cells/mm) and radicular (n = 10, 11.0 +/- 4.1 cells/mm) cyst linings (P < 0.005). The epithelial distribution of PCNA+ cells differed between groups with the basal/suprabasal PCNA+ cell ratio in OKC linings (0.05 +/- 0.02) being significantly lower than that of normal oral epithelium (0.5 +/- 0.14), dentigerous (1.6 +/- 1.23) and radicular (1.9 +/- 1.09) cyst linings respectively (P < 0.005). These results demonstrate differences in PCNA expression between the epithelial linings of the major odontogenic cyst types, indicating differences in proliferative and differentiation processes within these lesions.

Antigens, Neoplasm↗
PubMed1993

Expression of epidermal growth factor receptors by odontogenic jaw cysts.

The expression of epidermal growth factor receptor (EGFr) by odontogenic epithelium was studied in odontogenic cysts (n = 35), ameloblastoma (n = 6), and periapical granulomas containing proliferating epithelial rests of Malassez (n = 7) using a panel of monoclonal antibodies to EGFr (clone E30, F4 and C11) known to react with formalin-fixed, paraffin-embedded sections. Odontogenic epithelium in all specimens demonstrated immunoreactivity with all three antibodies. Clone E30 consistently gave the most intense, membrane located staining pattern of the three antibodies tested. Generally, staining of epithelial cells progressively diminished with movement away from the basal cell layers toward the most superficial layers of cystic lining or centre of epithelial rests and tumour islands. Developmental odontogenic cysts (odontogenic keratocysts, n = 13; dentigerous cysts, n = 11) and ameloblastoma (follicular type, n = 5; unicystic type, n = 1) expressed a higher level of EGFr staining than inflammatory cysts (radicular cysts, n = 11) and the proliferating epithelial rests in periapical granulomas. However, foci of weak EGFr staining of odontogenic keratocyst lining, similar to that seen in radicular cysts, were found in areas associated with inflammation. In addition, epithelial rests not associated with inflammatory cell infiltrates exhibited stronger reactivity for EGFr than proliferating rests within periapical granulomas. These results indicate that the level of EGFr expression by odontogenic cysts and rests is related to the presence of inflammation within adjacent connective tissue and that there is no detectable difference in receptor expression between developmental cysts and ameloblastoma.

ErbB Receptors↗
PubMed1993

Tissue response to a haemostatic alginate wound dressing in tooth extraction sockets.

Kaltostat is a new haemostatic wound dressing composed of non-woven sodium calcium alginate fibres, and was originally developed to cover exposed wounds of the skin. A histopathological study was undertaken to determine the tissue response to Kaltostat in healing tooth sockets, to obtain a comparison with oxidised regenerated cellulose (Surgicel). Tooth sockets filled with blood clot acted as controls. The results showed that both biomaterials delayed wound healing in the early phase (1-4 weeks), giving rise to foreign body reactions. At 12 weeks there was little difference between the control sockets and the sockets containing the test materials, although remnants of retained dressing materials were identified. Healing of the tooth sockets was complete at 24 weeks.

Alginates↗
PubMed1993

Assessment of thermal damage in precooled CO2 laser wounds using biological markers.

Precooling of the tissues was investigated as a possible means of reducing the thermal damage during CO2 laser surgery of the oral mucosa. Standard wounds 5 mm long were created with the CO2 laser, with and without precooling, or the scalpel on the dorsum of tongues. Tissue damage was evaluated by studying changes in mast cells and in the activity of lactate (LDH) and succinate (SDH) dehydrogenase. Cooled unoperated tongues acted as controls. The area of thermal damage, indicated by loss of SDH activity, was significantly smaller in precooled tissues (p < 0.001). Although a similar pattern was detected using LDH, the difference was not significant. At both 0 and 6 h normal mast cell numbers were significantly different between groups (p < 0.02). Furthermore, at 0 time, there were significant differences in the numbers of degranulated mast cells between surgical treatment groups (p = 0.001), although not at 6 h. Total numbers of mast cells (normal and degranulated) did not differ between treatment groups or between 0 and 6 h sampling times. Positive significant correlations were observed between the cross-sectional areas and widths of non-reactive succinate and lactate dehydrogenase and the number of degranulated mast cells around the laser wounds. Analysis of the data demonstrated that (i) uncooled laser wounds but not precooled laser wounds were associated significantly with greater levels of immediate mast cell degranulation than scalpel wounds (p = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Roux-limb motility after total gastrectomy and Roux-en-Y anastomosis in patients with Zollinger-Ellison syndrome.

The Roux-en-Y syndrome was defined as chronic nausea, intermittent vomiting, and chronic abdominal pain worsened by eating in patients who have undergone a gastrojejunostomy Roux-en-Y reconstruction for peptic ulcer. When these patients fasted, the Roux limb showed striking abnormalities in motor function; when postprandial, they failed to convert to normal fed-state motor activity. In contrast, patients with Zollinger-Ellison syndrome do well after similar surgery; they can eat most foods and maintain their body weight. We studied the motility of the Roux limb and jejunum in six patients with Zollinger-Ellison after an esophagojejunostomy Roux-en-Y anastomosis. Roux-limb motor activity in these patients, as characterized by the migrating motor complex, was more frequent, well organized, and in synchrony with the remaining jejunum; most subjects also converted to the fed state after a liquid meal. We suggest that the enteric nervous system is intact and functions normally in patients who have had a Roux-en-Y reconstruction for ulcer disease secondary to Zollinger-Ellison, but not in patients with idiopathic peptic ulcer disease.

Adult↗
PubMed1992

Leuprolide acetate affects intestinal motility in female rats before and after ovariectomy.

Leuprolide acetate, a gonadotropin-releasing hormone (GnRH) analogue, is currently being proposed to control debilitating symptoms in women with functional bowel disease. Whether leuprolide alters gastrointestinal motility as part of its actions is unknown. This study was designed to assess, using myoelectric techniques in an animal model, the effects of leuprolide on potential mechanisms of neuromuscular function of small intestine. Female rats with (n = 6) or without (n = 8) bilateral ovariectomy were used to study jejunal motility before and after leuprolide therapy. Throughout the study, daily leuprolide dosages of 0.02, 0.2, or 0.4 micrograms/kg were injected into intact rats and 0.02, 0.2, 0.4, 1.0, or 2.5 micrograms/kg into ovariectomized rats. Recordings were made while the rats were fasted and postprandial and before and after leuprolide administration. Under control conditions, migrating myoelectric complexes (MMCs) were found in intact female rats, whether fasted or postprandial. After ovariectomy, postprandial controls and those treated with low-dose leuprolide (0.02, 0.2, and 0.4 micrograms) had typical fed-state patterns and no MMCs, but at 1.0 and 2.5 micrograms the fed state was inhibited and cycling MMCs occurred at a frequency similar to that of fasted controls. Reproductive hormones thus have a significant effect on gastrointestinal motility.

Animals↗
PubMed1991

A study of the relationship among pulpal response, microbial microleakage, and particle heterogeneity in a glass-ionomer-base material.

This investigation was designed to study the pulpal responses to glass-ionomer base materials that differ in particle size distribution. The study was carried out according to the BSI (1980) recommendations for testing restorative materials in vivo. The base materials caused more pulpal inflammation than the control material, Kalzinol, although by an indirect mechanism. A significant association was demonstrated in the statistical model between bacterial presence within the experimental cavity and pulpal inflammation. The type of restorative material has no direct association with the degree of inflammation, although the model suggests that it exerts an indirect influence via its antibacterial properties, and hence its influence on microbial microleakage. The base material, with a heterogeneous particle distribution, was associated with greater bacterial microleakage. Particle size distribution, therefore, has some effect upon bacterial microleakage, but, because of its complex effect upon several physical properties of materials, further studies are indicated.

Animals↗
PubMed1991

Pulpal response to two semihydrous glass ionomer luting cements.

This study compared the pulpal responses to two innovative semihydrous glass ionomer luting cements (STA and ZIN) with those previously obtained for a conventional anhydrous glass ionomer luting cement, Aquacem. ZIN contained zinc oxide in the formulation. The study was conducted according to the BSI (1989) recommendations for testing restorative materials in vivo. ZIN was associated with minimal pulpal changes and microbial microleakage, and differed little from the control material, Kalzinol. The pulpal response to STA was similar to that observed for Aquacem, but was associated with less microbial microleakage. The statistical model demonstrated a significant association between bacterial presence within the experimental cavity and pulpal inflammation. The closer that bacteria were to the pulp, the more severe was the ensuing inflammation.

Analysis of Variance↗
PubMed1990

Tooth pulp changes following Le Fort I maxillary osteotomy in a primate model.

Le Fort I maxillary 'down-fracture' osteotomy with 8 mm advancement was performed in 15 adult rhesus monkeys. Forty-five tooth pulps were examined histologically at intervals from 0 to 24 weeks after surgery. Cell degeneration occurred in 31% of pulps examined, necrosis in 16% of pulps and osteo-dentine was found in 7% of pulps. Almost half of the teeth examined (47%) showed marked cellular changes, more frequently found in posterior teeth. Other features noted were inflammation (13%) and reactive dentine in pulps (24%). Axons degenerated initially but recovered by 24 weeks. It is concluded that Le Fort I maxillary osteotomy caused pulpal disturbances in an animal model and the extent to which this occurs in patients needs to be carefully monitored.

Animals↗
PubMed1990

Juxtacortical osteosarcoma of the jaws.

Osteosarcoma is a highly malignant tumour which despite modern surgery and chemotherapy still retains a relatively poor prognosis. This prognosis is, however, much better in the rare variant known as juxtacortical osteosarcoma. Both types of osteosarcoma mainly affect the long bones but the juxtacortical variant may be treated less aggressively and has a much better survival rate. The authors report four cases of juxtacortical osteosarcoma affecting the jaws and discuss these unusual tumours and their management.

Adult↗
PubMed1990

A histological study of stainless steel and titanium screws in bone.

This study compared histologically the tissue response of stainless steel and titanium screws when inserted into the calvaria of eight beagle dogs for periods of 1, 4, 12, and 24 weeks. There was minimal fibrous reaction around both screw types with excellent long-term bone healing. After 24 weeks there was no discernable difference in the tissue reaction between the two types of screw.

Animals↗
PubMed1990

Effect of autogenous bone grafts on healing following Le Fort I maxillary osteotomies.

The healing of Le Fort I maxillary osteotomies was studied histologically in 12 adult rhesus monkeys to determine the effect of split autogenous rib grafts overlaying the osteotomy cuts on the lateral maxillary walls. The maxilla was advanced 8 mm in each animal, and examined at varying intervals up to 24 weeks after surgery. The results indicated that there were no obvious differences between the monkeys with and without the rib grafts. Both groups healed with good osseous union. It is concluded that autogenous rib grafts did not enhance bony healing.

Animals↗
PubMed1990

In vivo morphogenetic activity of dentine matrix proteins.

Matrix proteins (EDTA-soluble and collagenase-released) from rabbit dentine have been demonstrated to show in vivo morphogenetic activity in exposed pulps of ferret canine teeth. In young adult ferrets, the reparative dentine resembled normal primary tubular dentine with odontoblast-like cells lining its formative surface. The reparative response in older animals was seen as osteo-dentine deposition. In both cases, the reparative response was characterized by its intensity within a comparatively short time period and also by the low grade or complete absence of any localized inflammatory response. Dentine matrix proteins implanted in exposed pulps of teeth provide a good experimental model for analysing the cell-matrix interactions and events taking place during odontoblast differentiation and dentinogenesis.

Aging↗