Oncoplasty for lateral breast cancers

Abstract #5158

Introduction: 65% of breast cancers develop in the lateral pole, particularly superiorly. Following conservative treatment, , tumourectomy may produce a typical deformity of superolateral nipple-areolar complex (NAC) deviation. This unaesthetic deformity, is exaggerated by the post-operative irradiation mandated by contemporary breast conserving therapy. Primary utilisation of the oncoplastic technique, 'lateral mammaplasty', allows both the avoidance of such deformities and wider excision margins.
 Patients and methods: The principle behind the technique is the combination of a wide, wedge-shaped tumourectomy combined with NAC repositioning on a de-epithelialised dermoglandular pedicle. Sentinel lymph node biopsy or formal axillary dissection may be performed simultaneously either via a separate or combined incision for inferior and superior lateral mammaplasties respectively. Aesthetic outcomes were assessed on a five-point scale with 1 being excellent and 5 poor.
 Results: eighty-six patients, with a mean age of 53 years (range 29 – 75) underwent lateral mammaplasty. Fifty-five (64%) were palpable and 73 (86%) had simultaneous axillary surgery. Mean tumour size pre- and post-operatively were 29.8 mm (8 – 81) and 33.6 mm (0 – 140) respectively. Mean excision weight was 150g (24 – 484). Eleven (12.8%) required revisional surgery due to involved or close margins and the aesthetic outcome was graded highly satisfying or satisfying in 68 (79%).
 Discussion: lateral mammaplasty has been found to be simple to perform with a short learning-curve. With clear excision margins in 87.8%, it is oncologically sound and compares favourably with simple tumourectomy. It should be considered when the tumour-to-breast volume ratio anticipates an aesthetic deformity. We have found it to be particularly satisfactory after neo-adjuvant chemotherapy for large volume tumours when a positive clinical response allows conservative surgery. It is also useful for revisional surgery in cases of involved or close margins following initial tumourectomy.
 Conclusion: lateral mammaplasty became routine in our institution as it allows, with the assistance of a simple oncoplastic procedure, highly satisfying aesthetic outcomes and the added security of wide excision margins.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5158.

Do isolated cells (pN0i+) in the sentinel lymph node change the post-operative management in breast cancer?

Abstract #206

Background: immunohistochemical (IHC) analysis of the sentinel lymph node (SLN) allows detection of occult metastases not routinely diagnosed by conventional techniques. There is, however, no consensus concerning the post-operative management of those patients with IHC-positive (pN0i+) nodes: should one re-operate, change the medical treatment or alter the irradiation fields?
 Patients and methods: 2692 patients with early invasive breast cancer underwent conservative treatment with SLN biopsy between 2000 and 2006. SLN were evaluated with frozen section followed by serial-section HES and IHC if HES showed no tumour cells. Lymph node staging followed the accepted pTNM classification: pN0, pN0i+ (≤ 0.2mm, IHC+), pNmi (0.2-2mm) and pN1a (> 2mm). In 1506 patients with T1pN0 tumours : 143 were pN0i+, that is 10%. We compared the post-operative management of pN0 patients, who had no completion axillary dissection (CAD), to those pN0i+ who did. All positive SLNs underwent CAD according to our institutional protocol.
 Results: 15 of 143 (10.5%) pN0i+ patients showed metastases in their CAD; a single node in 10 cases, 2-3 in 4 and > 3 in one patient. Univariate analysis showed chemo- and hormono-therapy to be more frequently administered in pN0i+ (24.5% vs. 77.6%) compared to pN0 (9.1% vs. 55.8%) patients; p < 0.0001. Irrespective of the result of CAD, pN0i+ patients had significant modifications in their fields of lymphatic irradiation at the internal mammary (43.6% vs. 23.5%), supra-clavicular (40.9% vs. 21.5%) and sub-clavicular (13.5% vs. 3.7%) areas; p < 0.0001. Other predictive factors showed a similar pattern including age < 50 years (31.5% vs. 18.6%), tumour size bigger (1.51cm vs. 1.16 cm) and lymphovascular invasion (27.5% vs. 11.6%); p < 0,0001. After multivariate analysis, the sole decisive factor for chemotherapy between the two groups was the presence of nodal metastasis in CAD. The duration of this study is, however, insufficient to comment on the long-term implications for pN0i+ patients.
 Discussion: immunohistochemistry alone plays a decisive role in favour of chemotherapy in N+ supplementary AD in only 10% of pN0i+ (15/143) patients. However, this concerns only 1% (15/1506) of those undergoing IHC so may have significant resource implications and other factors were found to be more influential. Moreover, pN0i+ patients underwent additional lymphatic irradiation, to all 3 fields, more frequently.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 206.

Procalcitonin in stable and unstable patients with bronchiectasis

Presently used markers of infection in bronchiectasis are inadequate to judge stability or make decisions about antibiotic treatment during bacterial exacerbations. Procalcitonin (PCT) is a new marker that has been used in community-acquired pneumonia and promises to allow much more specific and sensitive monitoring of patients with bacterial infections. This is the first study assessing its use in bronchiectasis. Thirty-eight consecutive inpatients and 63 consecutive outpatients were included in the study. All patients had PCT, other inflammatory markers, and a symptom score recorded. Inpatients had these values repeated at day 5 and 10 of their stay, while receiving intravenous antibiotics. Outpatients: PCT levels were generally low in the outpatient group. PCT was significantly correlated to C-reactive protein. Higher levels were associated with increased symptoms (P = 0.09) and an increased likelihood of antibiotic prescription (P = 0.007). Inpatients: As a group, inflammatory markers were significantly higher than in the outpatient group (P = 0.007). There was no correlation between the levels of PCT and the other inflammatory markers. PCT concentrations were generally low (as with other markers), which may reflect mucosal infection. Larger studies are needed, but PCT seems unlikely to be able to guide treatment of an exacerbation in bronchiectasis. PCT may offer more promise as a measure of stability.

The use of virtual reality for training in carotid artery stenting: a construct validation study

BACKGROUND

Given that carotid artery stenosis (CAS) intervention is procedurally difficult, possesses an extensive learning curve, and involves a grave list of potential complications, construct validation of new non-clinical training devices is of increasing importance.

PURPOSE

To evaluate the construct validity of the Procedicus-Virtual Interventional Simulator Trainer (Procedicus-VIST) and its use as a training tool.

MATERIAL AND METHODS

Sixteen interventionalists (15 males, one female; mean interventional radiology [IR] experience >11 years) and 16 medical students (15 males, one female; no IR experience) received 1 hour of didactic instruction followed by an hour of familiarization training. Subjects then attempted to complete a carotid artery stenting procedure within 1 hour while their performance metrics were recorded. All participants completed a qualitative exit survey of subjective parameters using a visual analog scale.

RESULTS

Procedure and fluoroscopic time was 8.7 and 8.7 min greater in the novice group (P=0.0066 and P=0.0031), respectively. There were no significant differences in performances between the two groups in the remaining metrics of cine loops (number recorded), tool/vessel ratio, coverage percentage, and placement accuracy or residual stenosis. Contrast measurement metrics were found to be too imprecise for statistical analysis. Experienced and novice opinions differed significantly for six of 10 subjective parameters. No statistically significant difference in video-gaming habits was demonstrated.

CONCLUSION

With the exception of the metrics of performance time and fluoroscopic use, construct validity of the Procedicus-VIST carotid metrics were not confirmed. Virtual reality simulation as a training method was valued more by novices than by experienced interventionalists.

Eosinophilic airway inflammation and exacerbations of COPD: a randomised controlled trial

Evidence suggests that eosinophilic airway inflammation is important in the pathogenesis of severe chronic obstructive pulmonary disease (COPD) exacerbations. The present authors tested the hypothesis that a management strategy that aims to reduce sputum eosinophil counts is associated with a reduction in exacerbations of COPD. A total of 82 patients with COPD were randomised into two groups. One group was treated according to traditional guidelines (British Thoracic Society (BTS) group) and the other (sputum group) was treated with the additional aim of minimising eosinophilic airway inflammation, assessed using the induced sputum eosinophil count. The primary outcome was exacerbations, which were categorised as mild, moderate or severe. The frequency of severe exacerbations per patient per year was 0.5 and 0.2 in the BTS and sputum groups, respectively (mean reduction 62%). The majority of this benefit was confined to patients with eosinophilic airway inflammation. There was no difference in the frequency of mild and moderate exacerbations. The average daily dose of inhaled or oral corticosteroids during the trial did not differ between the groups. Out of 42 patients in the sputum group, 17 required regular oral corticosteroids to minimise eosinophilic airway inflammation. A management strategy that aims to minimise eosinophilic airway inflammation, as well as symptoms, is associated with a reduction in severe exacerbations of chronic obstructive pulmonary disease.

Multiple inflammatory hits and the pathogenesis of severe airway disease

Refractory or difficult-to-control asthma is associated with some clinical and pathological features normally associated with chronic obstructive pulmonary disease (COPD), raising the possibility that there are similarities in their pathogenesis. It is suggested that the coexistence of two or more inflammatory stimuli to the airway (multiple hits) is a key factor leading to the development of more severe airway disease. Airway inflammation in response to chronic inflammatory conditions elsewhere may be a particularly important additional inflammatory stimulus. The "multiple hit" hypothesis for the origins of severe airway disease has important implications for treatment and prevention, since identification and removal of additional inflammatory stimuli may delay progression of the underlying airway disease.

Intracellular trafficking in neurones and glia of fibroblast growth factor-2, fibroblast growth factor receptor 1 and heparan sulphate proteoglycans in the injured adult rat cerebral cortex

The potent gliogenic and neurotrophic fibroblast growth factor (FGF)-2 signals through a receptor complex comprising high-affinity FGF receptor (FGFR)1 with heparan sulphate proteoglycans (HSPGs) as co-receptors. We examined the intracellular dynamics of FGF-2, FGFR1 and the HSPGs syndecan-2 and -3, glypican-1 and -2, and perlecan in neurones and glia in and around adult rat cerebral wounds. In the intact cerebral cortex, FGF-2 and FGFR1 mRNA and protein were constitutively expressed in astrocytes and neurones respectively. FGF-2 protein was localized exclusively to astrocyte nuclei. After injury, expression of FGF-2 mRNA was up-regulated only in astrocytes, whereas FGFR1 mRNA expression was increased in both glia and neurones, a disparity indicating that FGF-2 may act as a paracrine and autocrine factor for neurones and glia respectively. FGF-2 protein localized to both cytoplasm and nuclei of injury-responsive neurones and glia. There was weak or no staining of HSPGs in the normal cerebral neuropil and glia nuclei, with a few immunopositive neurones. Specific HSPGs responded to injury by differentially co-localizing with trafficked intracellular FGF-2 and FGFR1. The spatiotemporal dynamics of FGF-2-FGFR1-HSPG complex formation implies a role for individual HSPGs in regulating FGF-2 storage, nuclear trafficking and cell-specific injury responses in CNS wounds.

Alveolar nitric oxide in adults with asthma: evidence of distal lung inflammation in refractory asthma

Recent studies have suggested that alveolar nitric oxide (NO) concentration is a noninvasive test of distal lung inflammation. The current study determined whether alveolar NO concentration can be measured in patients with asthma of varying severity, tested the hypothesis that there is an association between alveolar NO and bronchoalveolar lavage (BAL) eosinophil count and determined whether refractory asthma is characterised by a raised alveolar NO concentration. Finally, the present authors assessed the effect of 2 weeks of prednisolone (30 mg q.d.) on alveolar NO concentration. Alveolar NO concentration was both measurable and repeatable in patients with refractory asthma. A positive correlation was found between alveolar NO concentration and BAL eosinophil count but not with bronchial wash or sputum eosinophil count. Alveolar NO concentration was increased in patients with refractory asthma (7.1 ppb) compared with mild-to-moderate asthma (3.4 ppb) and normal controls (3.4 ppb) and reduced by treatment with prednisolone. In conclusion, these findings support the hypothesis that alveolar nitric oxide is a measure of distal airway inflammation and suggest that distal lung inflammation is present in refractory asthma.

Age-dependent changes in Fibroblast growth factor 2 (FGF-2) expression in mouse cerebellar neurons

Fibroblast growth factor 2 (FGF-2) is a neurotrophic factor that regulates many neuronal functions and survival. We have characterised FGF-2 expression immunohistochemically in the cerebellum of young (4 months) and old (22 months) mice. About half of the population of the granule cells (GC), and all Purkinje cells (PC) expressed FGF-2 in all folia of the cerebellum at both ages. FGF-2 showed differential intracellular localization: predominantly localised to the nuclei of GC and present mainly in the cytosol of PC. There was a statistically significant (P = 0.0028) reduction in the number of FGF-2-positive GC in the cerebella of old (41.3+/-0.91%) compared to young (48.5+/-1.67%) mice, whereas no statistically significant age-dependent difference occurred in the number of FGF-2 positive PC. These results indicate a possible role of FGF-2 in cerebellar ageing.

Importance of radiation time and dose factors on outcome for childhood medulloblastoma*

The purpose of this study was to investigate the relationship of posterior fossa radiation therapy duration (PFRTD) and relapse-free survival (RFS) following adjuvant craniospinal RT for childhood medulloblastoma. A retrospective audit was performed assessing all children aged <18 years managed with adjuvant craniospinal RT for medulloblastoma in Australia and New Zealand in 1980-1993. Children receiving prolonged (>180 days) pre-RT chemotherapy were excluded. Data were obtained for potential prognostic factors in domains of patient, tumour and treatment factors. Radiation therapy time factors assessed were PFRTD and time interval from surgery to commencement of RT (SRTD). The end-point assessed was RFS and analysis was performed using Cox regression and Kaplan-Meier survival. One hundred and eighty-nine children were identified from 10 oncology units, with data available from 182 children for analysis. Median follow up was 5.3 years. Seventy-three per cent of children presented with disease confined to the cerebellum; 13% had initial neuraxis disease. Macroscopic resection was described in 54%; 42% received adjuvant chemotherapy. Median RT dose and RT duration to PF was 55 Gy and 45 days, respectively. Seventy-eight relapses occurred with a 10-year actuarial RFS of 58.2% (standard error +/- 4%). On univariate analysis, increasing PF dose (P = 0.002), age >5 years (P = 0.006), and more thorough extent of surgical resection (P = 0.043) were associated with improved RFS; PFRTD (P = 0.20) and SRTD (P = 0.51) were not associated with RFS. On multivariate analysis, although both PF dose (P = 0.004) and extent of surgery (P = 0.045) remained strongly significant, RT duration was now associated with RFS (P = 0.049). Other factors assessed that did not reach significance were patient age, local tumour extent, presence of internal shunt and use of chemotherapy. The importance of local treatment factors was confirmed in this audit with established prognostic factors such as primary tumour macroscopic resection and adequate PF RT dose being associated with RFS. A treatment time effect is weakly suggested, although less significant than RT dose delivered.

Sputum eosinophilia and the short term response to inhaled mometasone in chronic obstructive pulmonary disease

BACKGROUND

An association between the sputum eosinophil count and the response to a 2 week course of prednisolone has previously been reported in patients with chronic obstructive pulmonary disease (COPD). Whether the response to inhaled corticosteroids is related to the presence of eosinophilic inflammation is unclear.

METHODS

A randomised, double blind, crossover trial of placebo and mometasone furoate (800 microg/day), each given for 6 weeks with a 4 week washout period, was performed in subjects with COPD treated with bronchodilator therapy only. Spirometric tests, symptom scores, chronic respiratory disease questionnaire (CRQ), and induced sputum were performed before and after each treatment phase.

RESULTS

Ninety five patients were recruited of which 60 were randomised. Overall there were no treatment associated changes in forced expiratory volume in 1 second (FEV(1)), total CRQ, or sputum characteristics. After stratification into tertiles by baseline eosinophil count, the net improvement in post-bronchodilator FEV(1) increased with mometasone compared with placebo progressively from the least to the most eosinophilic tertile. The mean change in post-bronchodilator FEV(1) with mometasone compared with placebo in the highest tertile was 0.11 l (95% CI 0.03 to 0.19). This improvement was not associated with a fall in the sputum eosinophil count.

CONCLUSIONS

An increased sputum eosinophil count is related to an improvement in post-bronchodilator FEV(1) following treatment with inhaled mometasone in COPD, but the improvement is not associated with a reduction in the sputum eosinophil count.

Tr�nendr�senassoziierte Muzine

BACKGROUND

The secretory cells of the human lacrimal gland show a PAS-positive reaction in cytochemical staining procedures, suggesting the production of mucous substances. Recently, these substances were differentiated according to modern molecular classifications.

RESULTS

Expression studies detected mRNA for MUC1, MUC4, MUC5AC, MUC5B, MUC6, and MUC7, whereas MUC2 transcripts were absent in all samples investigated. Immunohistochemistry revealed membrane-bound MUC1 at the apical surface of acinar cells, MUC5AC associated with goblet cells of excretory ducts, MUC5B and MUC7 in the cytoplasm of acinar cells, and MUC7 also in epithelial cells of excretory ducts. MUC2 (RT-PCR negative) and MUC6 (RT-PCR positive) were not detectable by immunohistochemistry. MUC4 mRNA was present in all samples from patients treated for dry eye but only in 6 of 30 glands from individuals who did not receive treatment with artificial tears. Dot-blot analyses clearly revealed increased amounts of MUC4, MUC5AC and MUC5B in the glands of elderly women who received treatment for dry eye as compared to the remaining samples.

CONCLUSION

These results confirm that the human lacrimal gland synthesizes a spectrum of mucins, some of which might be involved in the pathophysiology of dry eye syndrome.

Australian and New Zealand three-dimensional conformal radiation therapy consensus guidelines for prostate cancer

Three-dimensional conformal radiation therapy (3DCRT) has been shown to reduce normal tissue toxicity and allow dose escalation in the curative treatment of prostate cancer. The Faculty of Radiation Oncology Genito-Urinary Group initiated a consensus process to generate evidence-based guidelines for the safe and effective implementation of 3DCRT. All radiation oncology departments in Australia and New Zealand were invited to complete a survey of their prostate practice and to send representatives to a consensus workshop. After a review of the evidence, key issues were identified and debated. If agreement was not reached, working parties were formed to make recommendations. Draft guidelines were circulated to workshop participants for approval prior to publication. Where possible, evidence-based recommendations have been made with regard to patient selection, risk stratification, simulation, planning, treatment delivery and toxicity reporting. This is the first time a group of radiation therapists, physicists and oncologists representing professional radiotherapy practice across Australia and New Zealand have worked together to develop best-practice guidelines. These guidelines should serve as a baseline for prospective clinical trials, outcome research and quality assurance.

Three-dimensional conformal radiotherapy in the treatment of prostate cancer in Australia and New Zealand: Report on a survey of radiotherapy centres and the proceedings of a consensus workshop

There is an increasing use of 3-D conformal radiotherapy (3DCRT) in the radiotherapeutic management of prostate cancer. The Faculty of Radiation Oncology Genito-Urinary Group carried out a survey of Australian and New Zealand radiotherapy centres in the preparation of a consensus workshop. Of the 19 centres that were represented, there were 24 radiation oncologists, 16 radiation therapists and 12 medical physicists. The survey collected demographic information and data on the practices undertaken at those centres when delivering curative radiotherapy in the treatment of prostate cancer. There was much variation in the delivery of treatment in the areas of patient set-up, contouring of target volumes and organs of interest during computer planning, the techniques and the dose constraints used in these techniques, the use of adjuvant androgen deprivation therapy and the quality assurance processes used in monitoring effects of treatment. This variability reflects the range of data in the published literature. Emerging trends of practices were also identified. This is a first report on a multi-disciplinary approach to the development of guidelines in 3DCRT of prostate cancer.

Dynamic molecular resolution imaging of preocular fluid impressions

AIM

The preocular fluid is renewed with molecules secreted by the underlying cells and with lacrimal gland secretions, while maintaining a stable surface topography. The authors tested the hypothesis that interactions between gelled and newly inserted mucins are the key to this stability.

METHODS

Using atomic force microscopy, the authors studied the topography of the freshly isolated preocular fluid obtained by impression cytology. The effects of adding mucins to this impression were compared with adding mucins to a pure mucin macromolecular assembly as a single component control to the more complex preocular fluid. The control structure was built up by repeated addition of pure ocular mucin to a tethering surface.

RESULTS

Imaging at molecular resolution showed a thin layer of superficial preocular fluid with an appearance consistent with a gel that was very flat, with surface roughness of approximately 0.1 nm. Mucin molecules adhering to a clean flat surface maintained their individual character when overlapping, whereas molecules integrating in the impression could not be followed individually. Both the preocular impression and the pure mucin assembly were stable under imaging for at least 90 minutes. The roughness of the pure mucin network decreased as more mucin was added. In contrast, there was a small increase in the roughness of the 2.25 microm2 area of impression over the 60 minutes of continuous imaging, although locally there appeared to be infill of low height features. Disulphide bond breaking resulted in the collapse of the imaged structure in both the pure mucin control and the more complex ex vivo preocular impression.

CONCLUSIONS

Polymeric mucins linked by disulphide bonds prevent or lessen loss of ocular surface material into the surrounding aqueous tears.

Venous flow restriction: the role of vein wall motion in venous admixture

OBJECTIVE

There are wide differences in flow between vascular beds at rest, even more during stress. The hydrodynamic energy (Energy grade line or EGL) of venous outflows must also vary considerably between vascular beds. We explored the mechanism of venous admixture of differing energy flows using a mechanical model.

MATERIALS AND METHODS

The model simulated two venous flows coalescing at a venous junction and then flowing through collapsible venous pumps. Flow rates and pressures were monitored when the venous pumps were full (steady state) and when they were compressed and allowed to refill inducing wall motion (pump flow).

RESULTS

With increasing EGL differences between two coalescing venous flows, reduction or cessation (venous flow restriction) of the weaker flow occurred during steady state; higher base EGL of both flows ameliorated venous flow restriction and lower base EGL the opposite. Outflow obstruction favoured venous flow restriction. Pump action in the vicinity of the venous junction abolished venous flow restriction and maximized both venous flows.

CONCLUSION

The model suggests a pivotal role for vein wall motion in venous admixture and regional perfusion. Observations in the model are explained on the basis of network flow principles and collapsible tube mechanics.

CTb targeted non-viral cDNA delivery enhances transgene expression in neurons

BACKGROUND

Efficient neuronal gene therapy is a goal for the long-term repair and regeneration of the injured central nervous system (CNS). We investigated whether targeting cDNA to neurons with cholera toxin b chain conjugated non-viral polyplexes led to increased efficiency of non-viral gene transfer in the CNS. Here, we illustrate the potential for this strategy by demonstrating enhanced transfection of a differentiated neuronal cell type, PC12.

METHODS

In vitro transfection efficiency of a cholera toxin b chain-poly(D-lysine) molecular conjugate (CTb-K(100)) was compared by fluorescence-activated cell sorting (FACS) analysis of green fluorescent protein (GFP) expression and luminometric measurement of beta-galactosidase (beta-gal) expression, to untargeted poly(D-lysine) (K(100)) in undifferentiated and NGF-differentiated PC12 cells.

RESULTS

Transfection of undifferentiated PC12 cells with CTb-K(100) polyplexes resulted in a 36-fold increase in levels of pCMV-DNA(LacZ) expression and a 20-fold increase in the frequency of transduction with pCMV-DNA(GFP), compared with untargeted K(100) polyplexes. Treatment of PC12 cells with 50 ng/ml/day of NGF for 14 days led to differentiation to a neuronal phenotype. Transfection of NGF-differentiated cells with CTb-K(100) polyplexes resulted in a 133-fold increase in levels of pCMV-DNA(LacZ) expression and a 11-fold increase in the percentage of cells transduced with pCMV-DNA(GFP), compared with untargeted K(100) polyplexes. Transfection was dependent on CTb, with CTb-K(100)-mediated transfections competitively inhibited with free CTb in both PC12 phenotypes.

CONCLUSIONS

Non-viral systems for gene transfer in damaged CNS show superior toxicological profiles to most viruses but are limited by inefficient and non-selective gene expression in target tissue. Cholera toxin is known to interact preferentially with neuronal cells of the central and peripheral nervous systems, mediating binding through the b subunit, CTb, and the pentasaccharide moiety of the gangliosaccharide, GM1, which is present at high levels on the neuronal cell surface. Here, we show that a molecular conjugate of the CTb subunit, covalently linked to poly(D-lysine), is able to successfully target and significantly enhance transfection of a neuronal cell type, NGF-differentiated rat PC12 pheochromocytoma cells. This observation encourages the further development of non-viral strategies for the delivery of therapeutic genes to neurons.

Human preocular mucins reflect changes in surface physiology

BACKGROUND/AIMS

Mucin function is associated with both peptide core and glycosylation characteristics. The authors assessed whether structural alterations occurring during mucin residence in the tear film reflect changes in ocular surface physiology.

METHODS

Ocular surface mucus was collected from normal volunteers as N-acetyl cysteine (NAcCys) washes or directly from the speculum after cataract surgery. To assess the influence of surface health on mucins, NAcCys washings were also obtained from patients with symptoms, but no clinical signs of dry eye (symptomatics). Mucins were extracted in guanidine hydrochloride (GuHCl) with protease inhibitors. Buoyant density of mucin species, a correlate of glycosylation density, was followed by reactivity with anti-peptide core antibodies. Mucin hydrodynamic volume was assessed by gel filtration on Sepharose CL2B.

RESULTS

Surface fluid and mucus contained soluble forms of MUC1, MUC2, MUC4, and MUC5AC and also the same species requiring DTT solubilisation. Reactivity with antibodies to MUC2 and MUC5AC peaked at 1.3-1.5 g/ml in normals, while dominated by underglycosylated forms in symptomatics. Surface mucins were predominantly smaller than intracellular species. MUC2 size distributions were different in symptomatics and normals, while those of MUC5AC were similar in these two groups.

CONCLUSIONS

A reduction in surface mucin size indicates post-secretory cleavage. Dissimilarities in surface mucin glycosylation and individual MUC size distributions in symptomatics suggest changes in preocular mucin that might precede dry eye signs.