Diet and risk factors for age-related maculopathy

BACKGROUND

Evidence continues to accumulate that oxidative stress is etiologically important in the pathogenesis of age-related maculopathy (ARM) and that appropriate antioxidants of dietary origin may protect against this condition.

OBJECTIVE

Risk factors for ARM may be classed as established or putative. We report a study designed to investigate whether such risk factors are associated with a dietary lack of antioxidants relevant to retinal health.

DESIGN

Dietary, anthropometric, and sociodemographic details relating to 828 healthy Irish subjects aged 20-60 y were recorded in a cross-sectional fashion and analyzed for associations between risk factors for ARM and dietary intake of relevant nutrients.

RESULTS

Of the established risk factors for ARM, increasing age was associated with a relative lack of dietary zeaxanthin (P < 0.05) and tobacco use with a relative lack of dietary vitamin C (P < 0.05). Of the putative risk factors for ARM, alcohol consumption was associated with a relative lack of dietary alpha-linoleic acid (P < 0.05), and female sex was associated with a relative lack of dietary zinc (P < 0.05).

CONCLUSIONS

We showed that several variables related to risk for ARM are associated with a relative dietary lack of key nutrients. Our finding that age, the most important and universal risk factor for ARM, is associated with a relative lack of dietary zeaxanthin, is an important finding that warrants further investigation.

The improved specificity of bovine brucellosis testing in Great Britain

The brucellosis surveillance scheme in Great Britain includes the serological testing of approximately 1 million bovine samples per year. These are screened by iELISA, positives going forward for confirmatory testing by CFT and SAT. Samples positive by confirmatory testing prompt substantial field investigations and interventions, but the animals involved are usually uninfected. Described below are a series of modifications to the screening method, which have resulted in a 10-fold reduction in false positive results whilst maintaining sensitivity. The key modifications include the introduction of blocking agents, a change in serum test dilution and the introduction of a control that directly defines the positive/negative cut-off. These simple modifications have had a large impact in reducing the cost of the surveillance programme due to reductions in confirmatory test requirements and a knock on effect of reducing costly field intervention.

Deferral of first review after uneventful phacoemulsification cataract surgery until 2 weeks

PURPOSE

To investigate the safety of deferring the ophthalmic review after uneventful phacoemulsification cataract surgery until 2 weeks after the procedure.

SETTING

Waterford Regional Hospital, Waterford, Ireland.

METHODS

After uneventful cataract surgery, 233 patients were randomized to have ophthalmic review 2 hours after the procedure and 2 weeks postoperatively (Group 1) or to forego any ophthalmic review before the 2-week postoperative visit in the outpatient department (Group 2).

RESULTS

Of the 115 patients randomized to Group 1, 25 (21.7%) had intraocular pressure (IOP) spikes of 30 mm Hg or greater and 2 (1.7%) had a corneal abrasion in the immediate postoperative period. Group 1 and Group 2 were statistically similar in terms of problems encountered in the first 2 postoperative weeks and anterior segment findings and visual acuity at the 2-week postoperative visit.

CONCLUSIONS

The results of this randomized controlled study indicate that the first ophthalmic review after uneventful cataract surgery can be safely deferred until 2 weeks postoperatively in patients in whom a transient IOP spike would not be deemed clinically deleterious. Such a policy will enhance the efficiency of day-surgery units.

The relationships between macular pigment optical density and its constituent carotenoids in diet and serum

PURPOSE

Lutein (L) and zeaxanthin (Z) are two dietary carotenoids that accumulate at the macula, where they are collectively known as macular pigment (MP). There is a biologically plausible rationale, with some supporting evidence, that MP may protect against age-related maculopathy (ARM). This study was undertaken to investigate the relationship between dietary intake of L and Z, serum concentrations of these carotenoids, and MP optical density in 828 healthy Irish subjects.

METHODS

Dietary intake of L and Z was assessed with a validated food-frequency questionnaire, and serum concentrations of these carotenoids were quantified by high-performance liquid chromatography. MP optical density was measured psychophysically, using heterochromatic flicker photometry. Demographic data, lifestyle data, and general health status, were also recorded by questionnaire, with particular attention directed toward risk-factors (established and putative) for ARM.

RESULTS

The relationships between MP optical density, serum concentrations of L (and Z), and dietary intake of L (and Z) were positive and statistically significant when analyzed for the entire study group (r = 0.136-0.303; P < 0.01 for all). Subjects with a clinically confirmed family history of ARM, current heavy cigarette smokers, subjects aged more than 53 years, and subjects with a body mass index (BMI) >27, did not demonstrate a positive and significant relationship between MP optical density and serum concentrations of Z (r = 0.041, r = 0.001, r = 0.074 and r = 0.082, respectively; P > 0.05 for all). However, there was a positive and significant relationship between MP optical density and serum concentrations of L in the presence of all these risk factors (r = 0.165 to 0.257), except for current heavy smokers (r = 0.042; P > 0.05).

CONCLUSIONS

For subjects at increased risk of ARM (e.g., subjects with a clinically confirmed family history of ARM, current heavy cigarette smokers, subjects aged > 53 years and subjects with a BMI > 27) retinal capture and/or retinal stabilization of Z appears to be compromised, whereas retinal uptake and/or stabilization of L appears to be compromised in current heavy smokers only. Given the lack of MP in association with risk for ARM, the findings indicate that a retina predisposed to this condition may have an impaired ability to accumulate circulating Z.

Validation of a fluorescence polarization assay (FPA) performed in microplates and comparison with other tests used for diagnosing B. melitensis infection in sheep and goats

Fluorescence polarization assay (FPA) is a relatively new test for the serological diagnosis of Brucella spp. infection in animals. FPA, carried out in 96-well microplate format, was validated here for diagnosing B. melitensis infection in sheep and goats. This study included sera from 1933 sheep and goats, from animals reared in naturally infected flocks (verified by culture) and showing a positive reaction to two different tests conducted in parallel. In addition, 2154 sera originating from healthy sheep and goats, reared in areas where B. melitensis had never been isolated, were assayed. The optimum cut-off value offering the highest diagnostic sensitivity (DSn) and diagnostic specificity (DSp) was determined at 15 mP over the mean value of the buffer control used in each microplate as determined by receiver operating characteristic analysis. The DSn and DSp of the FPA for small ruminants carried out in microplates at this cut-off value were calculated to be 95.9% and 97.9% with 95% confidence intervals (95% CI) of 94.9-97.7% and 97.2-98.4%, respectively. The accuracy of the FPA, as expressed by determination of the area under the curve, was 0.991. Indirect ELISA and FPA tests offered the highest DSn when compared with the Rose Bengal test, the complement fixation test, the modified Rose Bengal test and competitive ELISA. The parallel or serial combination of FPA with indirect ELISA offers the highest DSn and DSp. As temperature can affect the results of the FPA, all reagents must be at the same temperature and the standard for comparison must always be read under the same conditions as the sera under test. FPA performed in microplates is a promising assay; the DSn and accuracy are better than those of the tests currently approved for diagnosing B. melitensis in small ruminants. Because of its simplicity, speed, and accuracy, this test can improve capacity for laboratory testing and the efficacy of an eradication program based on a test-and-slaughter policy.

Risk factors for age-related maculopathy are associated with a relative lack of macular pigment

Macular pigment (MP) is composed of the two dietary carotenoids lutein (L) and zeaxanthin (Z), and is believed to protect against age-related maculopathy (ARM). This study was undertaken to investigate MP optical density with respect to risk factors for ARM, in 828 healthy subjects from an Irish population. MP optical density was measured psychophysically using heterochromatic flicker photometry, serum L and Z were quantified by HPLC, and dietary intake of L and Z was assessed using a validated food-frequency questionnaire. Clinical and personal details were also recorded, with particular attention directed towards risk factors for ARM. We report a statistically significant age-related decline in MP optical density (r2=0.082, p<0.01). Current and past smokers had lower average MP optical density than never smokers and this difference was statistically significant (p<0.01). Subjects with a confirmed family history of ARM had significantly lower levels of MP optical density than subjects with no known family history of disease (p<0.01). For each of these established risk factors, their statistically significant negative association with MP persisted after controlling for the other two, and also after controlling for other potentially confounding variables such as sex, cholesterol, dietary and serum L (p<0.01). In the absence of retinal pathology, and in advance of disease onset, the relative lack of MP seen in association with increasing age, tobacco use and family history of ARM supports the hypothesis that the enhanced risk that these variables represent for ARM may be attributable, at least in part, to a parallel deficiency of macular carotenoids.

Assessment of serological response of young and adult sheep to conjunctival vaccination with Rev-1 vaccine by fluorescence polarization assay (FPA) and other serological tests for B. melitensis

The serological response of young and adult sheep vaccinated conjunctivally with Rev-1 vaccine was assessed by fluorescence polarization assay (FPA), Rose Bengal test (RBT), complement fixation test (CFT), modified Rose Bengal test (m-RBT), indirect ELISA (i-ELISA) and competitive ELISA (c-ELISA), at different post vaccination intervals. One hundred and thirty six adult sheep and 64 lambs were used in the study. The vaccinated animals were bled prior to vaccination (0 day) and thereafter at 21st, 42nd, 35th, 63rd, 91st, 125th, 159th, and 223rd and 330th day post vaccination. The majority of animals (young and adult) showed positive reaction by FPA, RBT, CFT, m-RBT and c-ELISA 21 days post vaccination, whereas by i-ELISA at 42 days. All tests perform equal when animals vaccinated as young are tested 125 days (4 months) post vaccination. In case of animals vaccinated at adulthood, FPA, RBT, CFT and c-ELISA perform equal if the animals are tested 223 days (approximately 8 months) post vaccination. I-ELISA and m-RBT show low specificity if ewes vaccinated at adulthood are tested 330 days (11 months) post vaccination. If control of brucellosis in sheep is based on conjunctivally vaccination of lambs with Rev-1, the vaccinated animals can be tested by any test used for diagnosis of B.melitensis infection accurately at least 4 months post vaccination. If brucellosis control is based on mass vaccination the use of m-RBT and i-ELISA is not recommended for testing adult animals at least for 330 days (11 months) post vaccination due to tests low specificity. Further research is needed so the appropriate cut-offs to be established for FPA, c-ELISA or i-ELISA to become valuable tools for the eradication of Brucella spp. infection in small ruminants in areas where vaccination is practiced.

The impact of new regulations on the incidence and severity of ocular injury sustained in hurling

AIM

To prospectively evaluate, and compare, the incidence of hurling-related eye injuries in the South East of Ireland before and after implementation of new rules rendering the use of protective head gear and face masks compulsory for players aged 18 years or under.

METHODS

Details relating to patients attending the regional ophthalmic department with injuries sustained during hurling were prospectively recorded between 1 October 2003 and 31 March 2006.

RESULTS

Sixty players attended with hurling-related ocular injuries during the study period. Of these, 43 (71.6%) and 17 (28.3%) sustained the ocular injuries during the 15-month period before, and after implementation of the new rules (1 January 2005), respectively. Restricting our analysis to players aged 18 years or under, and, for statistical validity, to the 12-month period immediately before and immediately after implementation of the new rules, a statistically significant reduction in the number of hurling-related injuries was seen (1 January 2004 to 31 December 2004: 11; 1 January 2005 to 31 December 2005: 2; chi(2) test P<0.05) in this age group. A permanent visual deficit was seen in 11 (18.3%) patients. Of these, one (9%) was aged 18 years or under, and this injury was sustained before the new regulations.

CONCLUSION

New rules rendering the use of protective eye wear compulsory for players aged 18 years or under have resulted in a significant reduction in the incidence and severity of hurling-related eye injuries in this age group.

Abdominal aortic invasion by leiomyosarcoma

We describe a case of retroperitoneal leiomyosarcoma with extra- and intravascular involvement. The patient presented with abdominal aortic rupture secondary to tumor invasion and extensive tumor thrombus in the inferior vena cava. The presence of a rupture of the abdominal aorta is an important radiologic diagnosis to make because early endovascular or surgical repair can prevent a catastrophic free rupture. Inferior vena cava involvement by leiomyosarcoma may be locally resected in some cases but has a poor long-term survival rate.

Macular pigment and ocular biometry

This study is designed to investigate the relationship between macular pigment optical density (MPOD) and ocular biometric parameters. The following details were recorded for 180 healthy subjects: demographic profile; best-corrected visual acuity; refractive status; ocular biometric parameters [axial length (AL), anterior chamber depth (ACD), lens thickness (LT) and vitreous chamber depth (VCD)]; ocular dominance; MPOD; serum lutein (L) and zeaxanthin (Z). The mean MPOD (+/-SD) was 0.307 (0.155) and 0.305 (0.149) in the right and left eyes, respectively. No demonstrable relationship was observed between MPOD and AL, ACD or VCD [AL: r=0.091, p=0.225; ACD: r=0.091, p=0.227; VCD: r=0.146, p=0.051]. There was a significant and inverse relationship between LT and MPOD (r=-0.204; p=0.008), which was attenuated to non-significance after correction for age and height (r=-0.058; p=0.466). This study fails to identify an association between MPOD and ocular biometric parameters. This is an important negative finding, which allows investigators to study MP, and its relationship with potentially important variables, without the need to correct for ocular biometric parameters.

Serological discrimination by indirect enzyme immunoassay between the antibody response to Brucella sp. and Yersinia enterocolitica O:9 in cattle and pigs

A rapid, inexpensive and rugged serological test that distinguishes cattle and swine infected with Brucella sp. or Yersinia enterocolitica O:9 is described. The test protocol, which is an indirect enzyme immunoassay uses a high concentration of divalent cation chelating agents to minimize binding of Y. enterocolitica O:9 antibody to rough lipopolysaccharide antigen derived from B. abortus RB51. No false positive reactions were observed when testing 100 Canadian cattle and swine without any evidence of brucellosis. The assay detected 91.6% of cattle (n=155) and 93.5% (n=31) of swine infected with Brucella sp. Sera from 58 cattle and 38 swine exposed to Y. enterocolitica O:9 were negative while only 20 sera from 121 'false positive' reactors of unspecified origin gave low level positive reactions, eliminating 84% of the false positive reactions.

Macular pigment and percentage of body fat

PURPOSE

To investigate the relationship between percentage of body fat and macular pigment (MP) optical density.

METHODS

One hundred healthy subjects of ages between 22 and 60 years volunteered to participate in this study. MP optical density was measured psychophysically, serum lutein and zeaxanthin were quantified by HPLC, and dietary intake of lutein and zeaxanthin was assessed using a validated food frequency questionnaire. Body fat was measured by dual energy x-ray absorptiometry (DEXA); body mass index (BMI) was also calculated for each subject. Clinical and personal details were recorded, with particular attention directed toward putative risk factors for AMD.

RESULTS

There was a significant inverse relationship between the percentage of body fat and MP optical density in males (r=-0.392, P <0.01), and after correcting for age and dietary lutein and zeaxanthin, this inverse relationship remained significant (r=-0.290, P <0.05). The relationship between MP optical density and percentage of body fat in females was inverse, but not significant (r=-0.197, P=0.149). A significant and inverse relationship between serum zeaxanthin and percentage of body fat was observed for females only (r=-0.354, P <0.01). Dietary intake of fat was inversely related to serum lutein and zeaxanthin, and significantly so for lutein (r=-0.256, P <0.05). However, dietary fat was unrelated to MP optical density (r=0.041, P=0.688).

CONCLUSIONS

A relative lack of MP is associated with adiposity in men, and may underlie the association between body fat and risk for AMD progression in males. Further, the processes governing accumulation and/or stabilization of lutein and zeaxanthin in fat tissue appear to differ for males and females.

Survey of the seroprevalence of brucellosis in ruminants in Kosovo

A cross-sectional survey of the seroprevalence of brucellosis in sheep, goats and cattle in Kosovo was made in January 2001. A total of 12,000 serum samples, from 7941 cattle, 3548 sheep and 511 goats, were screened using the Rose Bengal test. Doubtful and positive results were further tested with competitive and indirect ELISAS. The overall serological prevalences derived from the samples positive to all three tests, were 6.26 per cent (95 per cent confidence intervals [CI] 5.5 to 7.1 per cent) for sheep, 7.24 per cent (5.3 to 9.8 per cent) for goats and 0.58 per cent (0.43 to 0.77 per cent) for cattle. The survey covered 26 of the 29 municipalities and showed that brucellosis was widely but unevenly distributed throughout the province. Seropositive animals were found in 25 per cent (19 to 32 per cent) of 162 villages surveyed. The risk of cattle being infected on holdings where both cattle and sheep were kept was greater, with a risk ratio of 4.6 (2.2 to 9.6), than on holdings where only cattle were kept. Brucella melitensis probably predominates as the cause of brucellosis in ruminants in the province of Kosovo.

A twelve-week, double-blind, randomized comparison of nortriptyline and paroxetine in older depressed inpatients and outpatients

Selective serotonin reuptake inhibitors may be less efficacious than tricyclic antidepressants in the treatment of severe depression in older patients. The authors compared the 12-week clinical outcome of older depressed patients treated with nortriptyline or paroxetine in a double-blind randomized comparison in 116 psychiatric inpatients and outpatients (mean age: 72+/-8 years) who presented with a major depressive episode or melancholic depression. Discontinuation and response rates were compared in patients who began or who completed treatment. The discontinuation rate due to side effects was significantly higher with nortriptyline than with paroxetine (33% vs. 16%). There were no significant differences between the rates of response in the Intent-to-Treat analysis (nortriptyline: 57% vs. paroxetine: 55% ), or the Completer analysis (nortriptyline: 78% vs. paroxetine: 84%). Although paroxetine appears to be better tolerated than nortriptyline, the efficacy of these two drugs does not appear to differ in the acute treatment of older depressed patients, including hospitalized patients and those with melancholic features.

A double-blind randomized comparison of nortriptyline and paroxetine in the treatment of late-life depression: 6-week outcome

BACKGROUND

Some studies have suggested that selective serotonin reuptake inhibitors may be less efficacious than tricyclic antidepressants in the treatment of severe depression in older patients. The objective of this study was to compare the 6-week outcome of treatment with nortriptyline and paroxetine in older patients with a major depressive episode.

METHOD

A double-blind randomized comparison of nortriptyline and paroxetine was conducted in 80 elderly (mean +/- SD age = 75.0 +/- 7.4 years) psychiatric inpatients and outpatients who presented with a major depressive episode. Dropout and response rates were compared in patients who began or completed treatment. Rates of response of inpatients and patients with melancholic depression were also compared.

RESULTS

Over 6 weeks, there were no significant differences in dropout rates due to side effects (nortriptyline, 14% vs. paroxetine, 19%) or for any reason (27% vs. 33%). Similarly, there were no significant differences between the rates of favorable response to nortriptyline or paroxetine (intent-to-treat analysis, 57% vs. 44%; completer analysis, 78% vs. 66%). Analyses restricted to inpatients or to patients with melancholic depression yielded similar results.

CONCLUSION

Nortriptyline and paroxetine appear to have similar efficacy and tolerability in the acute (6-week) treatment of older depressed patients, including hospitalized patients and those with melancholic features.

Development and application of a GFP-FRET intracellular caspase assay for drug screening

Apoptosis is a crucial biological process, and activation of caspase endoproteases is essential for proper regulation and execution of apoptosis. Because caspases also appear to be central players in several pathological states, there is a practical need within the biopharmaceutical research community for facile, noninvasive cellular assays for the discovery of compounds that modulate caspase activity. Tandem molecules of green fluorescent protein (GFP) stably expressed within cells can serve as a genetically encoded sensor of protease activity. Using this technology, we have developed a stable cellular system for the screening of agents that modulate activation of the caspase cascade. This assay technology allows for the real-time monitoring of apoptosis in situ, using conventional fluorescent plate reader detection. By applying this assay system to an actual compound screen, small-molecule inducers of cell apoptosis were reliably identified. Follow-up pharmacology confirmed that the rank-order potency of primary hits using the intracellular GFP assay corresponded to that found using a conventional, cell lysis-based assay method.

Weight change in older depressed patients during acute pharmacotherapy with paroxetine and nortriptyline: a double-blind randomized trial

The authors examined weight change in 32 elderly patients treated for 12 weeks with either nortriptyline or paroxetine during acute-phase pharmacotherapy. Random assignment to treatment and double-blind assessment of weight change were performed, including ascertainment of premorbid (i.e., pre-depression) weight. Pretreatment severity of depression was correlated with weight loss during the depressive episode and depression-related weight loss, in turn, correlated with weight regained during antidepressant treatment. There was no differential weight change associated with nortriptyline vs. paroxetine. Rather, subjects in both groups approximated their premorbid weights by 12 weeks of acute-phase pharmacotherapy with either agent. However, additional investigation of weight change during continuation and maintenance pharmacotherapy is necessary and would be clinically useful for the long-term management of elderly patients with depression.

Laparoscopic cholecystectomy in patients with hepatic cirrhosis: a five-year experience

Our institution is a tertiary referral center that specializes in hepatobiliary surgery. To evaluate the safety, efficacy, and conversion rate of laparoscopic cholecystectomy in patients with hepatic cirrhosis, we conducted a retrospective analysis of all cirrhotic patients undergoing attempted laparoscopic cholecystectomy during the period from 1991 to 1996. The diagnosis of cirrhosis was made on the basis of either a preoperative history, a liver biopsy, or the surgeon's operative description of the liver. All patients had early, well-compensated cirrhosis (Child's class A or B). A total of 30 patients underwent attempted laparoscopic cholecystectomy and five patients were converted to an open procedure (17%). The conversion rate for elective cases was 5% compared with 36% for urgent procedures. Two patients were converted because of varices and three because of unclear anatomy. No patients were converted because of bleeding. There were no operative deaths. The complication rate for elective procedures was 16%, with an average length of stay of 2.1 days, compared with 36% and 4.8 days, respectively, for urgent cases. Laparoscopic cholecystectomy in patients with early, well-compensated cirrhosis is safe and should be the treatment of choice for these patients.

Surfactant protein B deficiency: clinical, histological and molecular evaluation

Congenital alveolar proteinosis due to surfactant protein B deficiency is an inherited disease which results in severe respiratory failure in term infants soon after birth. The pathophysiologic basis of this disease is now known to be an inability to synthesise adequate quantities of normally functioning surfactant protein B. We report a male infant with fatal respiratory failure of neonatal onset, and histopathological features typical of those seen in congenital alveolar proteinosis. Molecular analysis of genomic DNA revealed two mutations, the 'common' 121ins2 mutation in exon 4, and a novel 2bp frameshift mutation in exon 5. We believe this is the first Australian case of surfactant protein B deficiency confirmed by molecular analysis.

Mortality from breast cancer in Ireland prior to the introduction of population-based mammographic screening

Mammographic screening has been shown in international randomised controlled trials and case-control studies to be effective in reducing mortality from breast cancer. Ireland has a high mortality rate from breast cancer when compared with rates from other countries. Organised population-based mammographic screening for breast cancer is about to begin in Ireland. The purpose of this study was to examine current mortality from breast cancer, as well as trends in breast cancer mortality in Ireland since 1975, as a baseline against which future evaluations of the impact of screening can be carried out. Over the 23-yr period of review, mortality from breast cancer appears to have remained quite stable. Within the period, however, there is some variation in adjusted rates, most notably an increase to a peak in 1989, followed by a decrease between 1989 and 1997. Continued monitoring of recent trends is required, with in-depth analysis of possible explanations, such as changing breast cancer incidence rates, biological characteristics, therapeutic regimes and coding practices.

Tendon shift in hallux valgus: observations at MR imaging

OBJECTIVE

This study was undertaken to demonstrate a shift in tendon alignment at the first metatarsophalangeal joint in patients with hallux valgus by means of magnetic resonance imaging.

DESIGN

Ten normal feet and 20 feet with the hallux valgus deformity conforming to conventional clinical and radiographic criteria were prospectively studied using magnetic resonance imaging. Correlation was made between tendon position at the first metatarsophalangeal joint and the severity of the hallux valgus deformity.

RESULTS

There is a significant shift in tendon position at the first metatarsophalangeal joint of patients with hallux valgus. The insertion of the abductor hallucis tendon is markedly plantarward and the flexor and extensor tendons bowstring at the first metatarsophalangeal joint compared with patients without the deformity. The severity of the tendon shift correlates with the hallux valgus angle and clinical severity of the hallux valgus deformity in each case.

CONCLUSION

Patients with hallux valgus have a significant tendon shift at the first metatarsophalangeal joint which appears to contribute to development of the deformity.

Predicting mandibular invasion in mouth cancer

This study assesses the role of orthopantomography, computerized tomography and intra-operative assessment in predicting the presence and extent of mandibular invasion by mouth tumours. Forty patient's with squamous carcinoma of the oral cavity and oropharynx were studied. All had pre-operative orthopantomography and computerized tomography as well as intra-operative assessment of mandibular invasion and these factors were compared with the actual histological invasion to assess the role of each test. This study found that negative radiology is useful for excluding cortical invasion and as might be expected is of no real value in excluding periosteal invasion, a positive orthopantomogram accurately predicts invasion at least into the cortex, however, a positive CT must be judged cautiously due to false positives and intra-operative assessment by an experienced operator is a useful adjunct to radiology.