Discriminating Glioblastoma from Peritumoral Tissue by a Nanohole Array-Based Optical and Label-Free Biosensor

In glioblastoma (GBM) patients, maximal safe resection remains a challenge today due to its invasiveness and diffuse parenchymal infiltration. In this context, plasmonic biosensors could potentially help to discriminate tumor tissue from peritumoral parenchyma based on differences in their optical properties. A nanostructured gold biosensor was used ex vivo to identify tumor tissue in a prospective series of 35 GBM patients who underwent surgical treatment. For each patient, two paired samples, tumor and peritumoral tissue, were extracted. Then, the imprint left by each sample on the surface of the biosensor was individually analyzed, obtaining the difference between their refractive indices. The tumor and non-tumor origins of each tissue were assessed by histopathological analysis. The refractive index (RI) values obtained by analyzing the imprint of the tissue were significantly lower (p = 0.0047) in the peritumoral samples (1.341, Interquartile Range (IQR) 1.339-1.349) compared with the tumor samples (1.350, IQR 1.344-1.363). The ROC (receiver operating characteristic) curve showed the capacity of the biosensor to discriminate between both tissues (area under the curve, 0.8779, p < 0.0001). The Youden index provided an optimal RI cut-off point of 0.003. The sensitivity and specificity of the biosensor were 81% and 80%, respectively. Overall, the plasmonic-based nanostructured biosensor is a label-free system with the potential to be used for real-time intraoperative discrimination between tumor and peritumoral tissue in patients with GBM.

[Topical use of tranexamic acid in total hip arthroplasties: retrospective analysis of its advantages]

INTRODUCTION

intravenous (IV) tranexamic acid (TXA) has shown its usefulness to prevent postsurgical anemia, but few studies have analyzed its topical administration. Seven years ago, we implemented a new topical administration (moistening three gauzes with 1.5 g of TXA) in our primary total hip arthroplasties (THA). The objective of this study was to compare blood loss, hospital stay and complications without the use of TXA, topical use or 10 mg/kg IV plus topical.

MATERIAL AND METHODS

consecutive retrospective series of 274 patients undergoing CTA (mean 70 years [59-76], 59% women) operated from 2014 to 2019. Loss of hemoglobin and hematocrit, blood transfusions, hospital stay, thromboembolic complications were compared and 30-day mortality among three groups: non-tranexamic (44.2%), topical (45.6%), topical + IV (9.9%).

RESULTS

after 24 and 48 hours, hemoglobin and hematocrit decreased less (p < 0.05) in patients treated with TXA (topical and/or IV). Blood transfusion was required in 32% of patients without TXA, 12% of those treated with topical TXA only (RR = 3.24 [95% CI: 1.69-6.20]), and 0% of patients who received IV TXA (p = 0.005) (RR = 4.07 [95% CI: 2.14-7.48]). Hospital stay was reduced three days with TXA (p < 0.001). We have not observed any adverse effects related to TXA.

CONCLUSIONS

the use of TXA in CTA significantly reduces anemia, transfusions and hospital stay without increasing complications. Isolated topical TXA (hemostatic pads) is less effective than topical IV + topical use, but both significantly improve anemia, transfusions, and hospital stay compared to no use.

Influence of cognitive impairment on mortality, complications and functional outcome after hip fracture: Dementia as a risk factor for sepsis and urinary infection

PURPOSE

To analyze the relation between cognitive impairment on arrival at hospital in patients older than 65 years with a hip fracture, and their mortality, medical and surgical complications, and functional outcomes.

PATIENTS AND METHODS

Observational study of a single-center prospective consecutive cohort of 955 patients older than 64 years diagnosed of hip fracture from December/2012 to December/2015. Average age was 86±7.2 (65-104) years and 725 (75.9%) were female. Fractures were extracapsular in 538 cases (56.3%) and intracapsular in 417 (43.7%). Patients were controlled clinically and radiographically in outpatient clinic after 1, 3, 6, and 12 months. Data about basal cognitive status, walking ability before the fracture, medical and surgical complications, functional outcomes and mortality were collected for the year following the fracture.

STATISTICAL ANALYSIS

Bivariate analysis (Pearson, Fisher, Mann-Whitney, Wilcoxon) was applied to study statistically significant relations, and contingence coefficients (CC) were calculated.

RESULTS

Patients with cognitive impairment showed a higher overall mortality, (p = 0,000; CC=0,197) even after hospital discharge (p = 0.000; CC=0.198). Similarly, patients with dementia presented a higher rate of respiratory infections (p = 0,029; CC=0,093), urinary tract infections (p = 0,008; CC=0,108) and sepsis (p = 0,011; CC=0,105). On the contrary, we found no correlations between mental status and surgical complications, even for prosthesis dislocation (p = 0.136). Patients with dementia started from poorer functional situations (p = 0,000; CC=0,367) and ended follow-up with lower walking ability (p = 0,000; CC=0,43), but cognitive impairment did not relate statistically with a worse functional recovery (p = 0,304): that is, the proportion of patients who maintained their previous ability to walk was similar in both groups, those with altered mental status and those without it.

CONCLUSIONS

Cognitive impairment is a risk factor for mortality in patients with a hip fracture. It is also a risk factor for suffering respiratory and urinary tract infection and sepsis. These two late risks factors have not been published previously. Functional recovery is not conditioned by cognitive impairment, although further studies need to be developed to evaluate the actual role of cognitive impairment on postoperative progression of patients.

Parent’s perceptions and concerns about inhaled asthma therapy

Aim: To determine parent´s perceptions and concerns about inhaled therapy and their relation to disease control. Methods:  A questionnaire was applied by interviewing parents of 119 asthmatic children attending the Pediatric Allergy or Pneumology outpatient clinic. Results: Eighty-one (68%) parents expressed concerns and worries about the use of inhaled therapy in their children, either with controlled or partially/uncontrolled asthma (65% Vs 78% p=0.22). Regarding their beliefs about inhaled therapy, 11% (n=13) stated that they considered pMDI’s/DPI’s less effective than nebulizers. When questioned about the knowledge of their child's acute exacerbation therapy, 91.5% (n=109) reported knowing it, albeit only 40% (n=44) did answer it correctly. Nine parents said they were unaware of their children’s reliever treatment. Discussion: We expected to find parental concerns about inhaled therapy, but such a high percentage wasn´t expected. A substantial number of parents believe that their children can become addicted or dependent on the use of the inhaler. This finding reinforces the misconceptions parents do have regarding inhaled therapy. There is a higher proportion of parents with concerns in the group with partially/uncontrolled asthma, although it was not statistically significant. The majority of patients/parents reported knowing the reliever plan in an exacerbation, although most of them could not explain the plan correctly. These results are worrying, as they show parents have an inappropriate knowledge of reliever measures. Therefore, we suggest that improvements in education about inhaled therapy should be made, including the regular review of the inhalation technique and the reliever plan in every consultation.

Full 3-D OCT-based pseudophakic custom computer eye model

We compared measured wave aberrations in pseudophakic eyes implanted with aspheric intraocular lenses (IOLs) with simulated aberrations from numerical ray tracing on customized computer eye models, built using quantitative 3-D OCT-based patient-specific ocular geometry. Experimental and simulated aberrations show high correlation (R = 0.93; p<0.0001) and similarity (RMS for high order aberrations discrepancies within 23.58%). This study shows that full OCT-based pseudophakic custom computer eye models allow understanding the relative contribution of optical geometrical and surgically-related factors to image quality, and are an excellent tool for characterizing and improving cataract surgery.

Arsenic levels in immigrant children from countries at risk of consuming arsenic polluted water compared to children from Barcelona

Arsenic is a highly toxic element that pollutes groundwater, being a major environmental problem worldwide, especially in the Bengal Basin. About 40% of patients in our outpatient clinics come from those countries, and there is no published data about their arsenic exposure. This study compares arsenic exposure between immigrant and native children. A total of 114 children (57 natives, 57 immigrants), aged 2 months to 16 years, were recruited and sociodemographic and environmental exposure data were recorded. Total arsenic in urine, hair, and nails and arsenic-speciated compounds in urine were determined. We did not find significant differences in total and inorganic arsenic levels in urine and hair, but in organic arsenic monomethylarsenic acid (MMA) and dimethylarsinous acid (DMA) in urine and in total arsenic in nails. However, these values were not in the toxic range. There were significant differences between longer than 5 years exposure and less than 5 years exposure (consumption of water from tube wells), with respect to inorganic and organic MMA arsenic in urine and total arsenic in nails. There was partial correlation between the duration of exposure and inorganic arsenic levels in urine. Immigrant children have higher arsenic levels than native children, but they are not toxic. At present, there is no need for specific arsenic screening or follow-up in immigrant children recently arrived in Spain from exposure high-risk countries.

Age-dependent variation of the Gradient Index profile in human crystalline lenses

PURPOSE: To reconstruct the gradient index (GRIN) profile of human crystalline lenses ex-vivo using Optical Coherence Tomography (OCT) imaging with an optimization technique and to study the dependence of the GRIN profile with age. METHODS: Cross-sectional images of nine isolated human crystalline lenses with ages ranging from 6 to 72 (post mortem time 1 to 4 days) were obtained using a custom-made OCT system. Lenses were extracted from whole cadaver globes and placed in a measurement chamber filled with preservation medium (DMEM). Lenses were imaged with the anterior surface up and then flipped over and imaged again, to obtain posterior lens surface profiles both undistorted and distorted by the refraction through the anterior crystalline lens and GRIN. The GRIN distribution of the lens was described with three variables by means of power function, with variables being the nucleus and surface index, and a power coefficient that describes the decay of the refractive index from the nucleus to the surface. An optimization method was used to search for the parameters that produced the best match of the distorted posterior surface. RESULTS: The distorted surface was simulated with accuracy around the resolution of the OCT system (under 15 µm). The reconstructed refractive index values ranged from 1.356 to 1.388 for the surface, and from 1.396 to 1.434 for the nucleus. The power coefficient ranged between 3 and 18. The power coefficient increased significantly with age, at a rate of 0.24 per year. CONCLUSION: Optical Coherence Tomography allowed optical, non-invasive measurement of the 2-D gradient index profile of the isolated human crystalline lens ex vivo. The age-dependent variation of the changes is consistent with previous data using magnetic resonance imaging, and the progressive formation of a refractive index plateau.

Helicobacter pylori first-line treatment and rescue option containing levofloxacin in patients allergic to penicillin

AIM

To assess the efficacy and tolerability of Helicobacter pylori first-line treatment (omeprazole-clarithromycin-metronidazole) and second-line rescue option (omeprazole-clarithromycin-levofloxacin) in patients allergic to penicillin.

PATIENTS

Prospective multicenter study including consecutive patients allergic to penicillin. Therapy regimens: First-line treatment (50 patients): Omeprazole (20mg b.i.d.), clarithromycin (500 mg b.i.d.) and metronidazole (500 mg b.i.d.) for 7 days. Second-line treatment (15 therapy failures out of the aforementioned 50 patients): Omeprazole (20mg b.i.d.), clarithromycin (500 mg b.i.d.) and levofloxacin (500 mg b.i.d.) for 10 days.

OUTCOME VARIABLE

Negative (13)C-urea breath test 8 weeks after completion of treatment.

RESULTS

(1) First-line treatment (omeprazole-clarithromycin-metronidazole): Per-protocol and intention-to-treat eradication rates were 55% (27/49; 95%CI=40-70%) and 54% (27/50; 95%CI=39-69%). Compliance with treatment and follow-up was complete in 98% of cases (one patient was not compliant due to nausea). Adverse events were reported in 5 patients (10%): 4 nausea, 1 diarrhoea. (2) Second-line treatment (omeprazole-clarithromycin-levofloxacin): Per-protocol and intention-to-treat eradication rates were both 73% (11/15; 95%CI=45-92%). Compliance with treatment and follow-up was complete in all the cases. Adverse events were reported in 4 patients (20%), which did not prevent the completion of treatment: Mild nausea (2 patients), and vomiting and myalgias/arthralgias (1 patient).

CONCLUSION

In H. pylori infected patients allergic to penicillin, the generally recommended first-line treatment with omeprazole, clarithromycin and metronidazole has low efficacy for curing the infection. On the other hand, a levofloxacin-containing regimen (together with omeprazole and clarithromycin) represents an encouraging second-line alternative in the presence of penicillin allergy.

Empirical rescue therapy after Helicobacter pylori treatment failure: a 10-year single-centre study of 500 patients

BACKGROUND

Several 'rescue' therapies have been recommended to eradicate Helicobacter pylori, but they still fail in >20% of the cases, and these patients constitute a therapeutic dilemma.

AIM

To evaluate the efficacy of different 'rescue' therapies empirically prescribed during 10 years to 500 patients in whom at least one eradication regimen had failed to cure H. pylori infection.

DESIGN

Prospective single-centre study.

PATIENTS

Consecutive patients in whom at least one eradication regimen had failed.

INTERVENTION

Rescue regimens included: (i) quadruple therapy with omeprazole-bismuth-tetracycline-metronidazole; (ii) ranitidine bismuth citrate-tetracycline-metronidazole; (iii) omeprazole-amoxicillin-levofloxacin; and (iv) omeprazole-amoxicillin-rifabutin. Antibiotic susceptibility was unknown (rescue regimens were chosen empirically).

OUTCOME

Eradication was defined as a negative (13)C-urea breath test 4-8 weeks after completing therapy.

RESULTS

Five hundred patients were included (76% functional dyspepsia, 24% peptic ulcer). Compliance rates with first-, second- and third-line regimens were 92%, 92%, and 95%, respectively. Adverse effects were reported by 30%, 37%, and 55% of the patients receiving second-, third-, and fourth-line regimens. Overall, H. pylori cure rates with the second-, third-, and fourth-line rescue regimens were 70%, 74%, and 76%, respectively. Cumulative H. pylori eradication rate with four successive treatments was 99.5%.

CONCLUSION

It is possible to construct an overall treatment strategy to maximize H. pylori eradication, on the basis of administration of four consecutive empirical regimens; thus, performing bacterial culture even after a second or third eradication failure may not be necessary.

Emmetropization and optical aberrations in a myopic corneal refractive surgery chick model

We studied the potential of myopic corneal refractive laser surgery to induce myopia (axial elongation) and potential interactions between aberrations (generally resulting from the procedure) and myopia development in chicks (Gallus domesticus). Ten white Leghorn chicks were monolaterally treated one day post-hatching with photorefractive keratectomy (PRK), with a nominal dioptric change of -9.9 D (imposed hyperopia). Axial length was measured using an adapted ultrasonic biometer; corneal radius of curvature was measured using a custom-built videokeratometer and spherical error and high order aberrations were measured using custom-built Hartmann-Shack aberrometer post-operatively on days 9, 12, 14 and 16 after hatching. Two-weeks after surgery, there were no significant differences in corneal radius of curvature between treated and control eyes. Astigmatism increased on average by a factor of 2.6 and 3rd and higher order aberrations by a factor of 4.3 after PRK. Both treated and control eyes were close to emmetropia, and no axial elongation was found in the treated eyes. The inability of the refractive procedure to achieve significant reductions in the corneal power could be attributed to the biomechanical properties of the chick eye. High order aberrations induced significant contrast decrease (by a factor of 1.7 at 4.5c/deg). However, reduced image quality neither produced myopic refractive error nor axial elongation in the treated eyes. Both normal and treated eyes emmetropized, indicating that increased amounts of aberrations do not appear to be a risk factor for myopia.

Customized computer models of eyes with intraocular lenses

We compared experimental wave aberrations in pseudophakic eyes with aspheric intraocular lenses (IOLs) to simulate aberrations from numerical ray tracing on customized computer eye models using corneal topography, angle lambda, ocular biometry, IOL geometry, and IOL tilt and decentration measured on the same eyes. We found high correlations between real and simulated aberrations even for the eye with only the cornea, and these increased on average when the IOL geometry and position were included. Relevant individual aberrations were well predicted by the complete eye model. Corneal spherical aberration and horizontal coma were compensated by the IOL, and in 58.3% of the cases IOL tilt and decentration contributed to compensation of horizontal coma. We conclude that customized computer eye models are a good representation of real eyes with IOLs and allow understanding of the relative contribution of optical, geometrical and surgically-related factors to image quality. Corneal spherical aberration is reduced by aspheric IOLs, although other corneal high order aberrations are still a major contributor to total aberrations in pseudophakic eyes. Tilt and decentration of the IOLs represent a relatively minor contribution of the overall optical quality of the eye.

Third-line rescue therapy with levofloxacin is more effective than rifabutin rescue regimen after two Helicobacter pylori treatment failures

BACKGROUND

In patients with a first eradication failure, a second (rescue) therapy still fails in > 20% of cases.

AIM

To compare rifabutin and levofloxacin rescue regimens in patients with two consecutive Helicobacter pylori eradication failures.

METHODS

Patients, in whom first treatment with omeprazole-clarithromycin-amoxicillin and a second trial with omeprazole-bismuth-tetracycline-metronidazole (or ranitidine bismuth citrate with these antibiotics) had failed, received 10 days of treatment with either rifabutin (150 mg b.d.) or levofloxacin (500 mg b.d.), plus amoxicillin (1 g b.d.) and omeprazole (20 mg b.d.). Cure rates were evaluated by the (13)C-urea breath test.

RESULTS

Twenty patients received rifabutin, and 20 levofloxacin. All the patients returned for follow-up. Compliance in the rifabutin group was 100%. Four patients in the levofloxacin group did not take the medication correctly (in two cases due to adverse effects: myalgia and rash). Side effects in the rifabutin and levofloxacin groups were reported in 60% and 50% of the cases, respectively. Five patients (25%) treated with rifabutin presented with leucopenia, and six (30%) treated with levofloxacin presented with myalgias. Per-protocol cure rates were 45% (95% confidence interval, 26-66%) in the rifabutin group, and 81% (57-93%) in the levofloxacin group (P < 0.05). Intention-to-treat cure rates were, 45% (26-66%) and 85% (64-95%), respectively (P < 0.01).

CONCLUSIONS

After two previous H. pylori eradication failures, a 10-day triple levofloxacin-based rescue regimen is more effective than the same regimen with rifabutin.

Effects of interactions among wave aberrations on optical image quality

Wave aberrations degrade the optical quality of the eye relative to the diffraction limit, but there are situations in which having slightly aberrated optics can provide some relative visual benefits. This fact led us to consider whether interactions among aberrations in the eye's wavefront produce an advantage for image quality relative to wavefronts with randomized combinations of aberrations with the same total RMS error. Total ocular wave aberrations from two experimental groups and corneal wave aberrations from one group were measured and expressed as Zernike polynomial expansions through the seventh-order. In a series of Monte Carlo simulations, modulation transfer functions (MTFs) for the measured wave aberrations were compared to distributions of artificial MTFs for wavefronts created by randomizing the sign or orientation of the aberrations, while maintaining the RMS error within each Zernike order. In a control condition, "synthetic" model eyes were produced by choosing each individual aberration term at random from individuals in the experimental group, and again MTFs were compared for original and randomized signs. Results were summarized by the MTF ratio: real MTF/mean simulated MTF, as a function of spatial frequency. For a 6mm pupil, the mean MTF ratio for total ocular aberrations was greater than 1.0 up to 60 cycles per degree, suggesting that the eye's aberrations are not independent and that there may be a positive functional consequences to their interrelations. This positive relation did not hold for corneal aberrations alone, or for the synthetic eyes.

Longitudinal changes of optical aberrations in normal and form-deprived myopic chick eyes

We performed measurements of refraction (with retinoscopy), axial length (with ultrasound biometry) and ocular aberrations (with a custom-built Hartmann-Shack aberrometer) on seven awake White-Leghorn chicks occluded monolaterally with diffusers for two weeks. Treatment started on the first day after hatching (day 0) and measurements were conducted on several days between day 0 and 13. Non-occluded eyes experienced normal emmetropization (decreasing hyperopia at 0.2 +/- 0.09 D/day and increasing axial length at 0.05 +/- 0.03 mm/day), while occluded eyes developed axial myopia (1.50 +/- 0.2 D/day and 0.12 +/- 0.02 mm/day). Interocular differences in refraction and axial length by day 13 were on average 17.43 D and 0.86 mm, respectively. Monochromatic high order aberrations decreased with age in both eyes. Average RMS (for 1.5 mm pupil diameter) decreased from 0.11 +/- 0.03 at day 0 to 0.06 +/- 0.03 microm (day 13) in occluded eyes, and from 0.12 +/- 0.05 to 0.03 +/- 0.01 microm in non-occluded eyes. MTF-based optical quality metrics also show an improvement with age. However, while this improvement occurs in both eyes, after day 8 myopic eyes tend to show significantly higher amounts of aberrations (and consequently worse best-corrected optical quality) than normal eyes. The degradation imposed by aberrations is small compared to that imposed by defocus and the diffuser. These results suggest a decrease of aberrations during development which does not seem to be visually guided. Myopic eyes showed slightly worse optical quality than normal eyes, suggesting that the geometrical changes resulting from excessive ocular axial growth also affect the optical quality of the ocular components.

Aberrometry: basic science and clinical applications

This paper addresses the concept, measurement and applications of wave aberrations. The ocular optics is not perfect. Apart from conventional low order aberrations (such as defocus and astigmatism) retinal images are degraded by other high order aberrations. Aberrometers typically measure ray deviations at the retinal plane, as a function of pupil position, i.e. local derivatives of the wave aberration. The paper discusses state of the art technology to measure the aberrations of the eye (cornea and crystalline lens), both monochromatic and polychromatic. The aberrometers described include the Hartmann-Shack wavefront sensor, laser ray tracing, spatially resolved refractometer or the corneal aberrations. This technology has been used to advance our understanding on several visual mechanisms, ocular conditions, and corrective methods. Applications include accommodation, myopia, aging, myopia, keratoconus, corneal refractive surgery, cataract surgery or contact lenses.

Helicobacter pylori first-line treatment and rescue options in patients allergic to penicillin

BACKGROUND

Helicobacter pylori eradication is a challenge in patients allergic to penicillin, especially those who have failed a first-eradication trial.

AIM

To assess the efficacy and tolerability of H. pylori first-line treatment and rescue options in patients allergic to penicillin.

METHODS

Prospective single centre study including 40 consecutive treatments administered to patients allergic to penicillin. Therapy regimens: First-line (12 patients) omeprazole, clarithromycin and metronidazole for 7 days; second-line (17 patients) ranitidine bismuth citrate, tetracycline and metronidazole for 7 days; third-line (nine patients) rifabutin, clarithromycin and omeprazole for 10 days; and fourth-line (two patients) levofloxacin, clarithromycin and omeprazole for 10 days.

OUTCOME VARIABLE

a negative (13)C-urea breath test 8 weeks after completion of treatment.

RESULTS

Per-protocol/intention-to-treat eradication rates were: first-line (64/58%); second-line (ranitidine bismuth citrate; 53/47%); third-line (rifabutin; 17/11%) and fourth-line regimen (levofloxacin; 100/100%). Compliance with treatment was generally good, except with the rifabutin-based regimen, which presented adverse effects in 89% of the patients, including four cases of myelotoxicity.

CONCLUSIONS

H. pylori-infected patients who are allergic to penicillin may be treated with a first-line treatment combining a proton-pump inhibitor, clarithromycin and metronidazole. Rescue options may include a regimen with ranitidine bismuth citrate, tetracycline and metronidazole. A levofloxacin-based rescue regimen (with proton-pump inhibitor and clarithromycin) may also represent an alternative, even when two or more consecutive eradication treatments have previously failed. However, rifabutin + clarithromycin + proton-pump inhibitor regimen is ineffective and poorly tolerated.

Ovine alpha-amylase genes: isolation, linkage mapping and association analysis with milk traits

On the basis of comparisons between cattle and sheep genome mapping information the ovine alpha-amylase gene was examined as a possible genetic marker for milk traits in sheep. The objective of the present study was to isolate, map and determine whether this gene is a candidate gene for milk traits. DNA fragments (832 and 2360 bp) corresponding to two different AMY genes were isolated, and one SNP in intron 3 and one GTG deletion in exon 3 of the 2360 bp DNA fragment were found. The 2360 bp ovine AMY DNA fragment was located on chromosome 1 by linkage mapping using the International Mapping Flock. No association was found between estimated breeding values for milk yield, protein and fat contents and AMY genotypes in a daughter design comprising 13 Manchega families with an average of 29 daughters (12-62) per sire.

Association of the heart fatty acid-binding protein (FABP3) gene with milk traits in Manchega breed sheep

The ovine fatty acid-binding protein type 3 gene has been chosen as a functional candidate gene for milk traits. Two different single nucleotide polymorphisms (SNPs) of ovine FABP3 gene have been tested in a daughter design comprising 13 families. No association was found between estimated breeding values for milk yield, protein and fat contents (FC) and genotypes across families using anova and transmission disequilibrium test (TDT). In within-family analysis, one family showed a significant effect for FC. These results could indicate linkage disequilibrium between the FABP3 gene and a quantitative trait loci (QTL) for FC, with the heterozygous genotype associated with a positive effect in this trait.

Empirical Helicobacter pylori "rescue" therapy after failure of two eradication treatments

AIM

Even with the current most effective Helicobacter pylori treatment regimens, approximately 20% of patients do not eradicate the infection. Several "rescue" therapies have been recommended, but they still fail to eradicate H. pylori in approximately 20-30% of the cases. Our aim was to evaluate the efficacy of different rescue therapies prescribed to patients in whom two consecutive H. pylori eradication regimens had failed.

METHODS

Design. Prospective single-centre study. Patients. Consecutive patients in whom two eradication regimens had failed to eradicate H. pylori. Intervention. Third eradication regimens included: (1) omeprazole-amoxicillin-clarithromycin for 7 days; (2) quadruple therapy with omeprazole-bismuth-tetracycline-metronidazole for 7 days; (3) omeprazole-amoxicillin-clarithromycin-bismuth for 14 days; and (4) omeprazole-amoxicillin-rifabutin for 14 days. H. pylori antibiotic susceptibility was unknown and, therefore, rescue regimens were chosen empirically. In no case, was the same regimen repeated. Outcome. H. pylori eradication was defined as a negative in 13C-urea breath test 8 weeks after completing the therapy.

RESULTS

Forty-eight patients were included (mean age 45 years, 44% males, 82% with peptic ulcer and 18% with functional dyspepsia). No patient was lost from follow-up. Adverse effects were described in 21% of the patients. One patient receiving omeprazole, amoxicillin and rifabutin was removed from medication due to adverse effects (vomiting). Overall, mean H. pylori eradication with third therapy after failure of two eradication treatments was 34/48 (71%; 95% confidence interval 57-82%) by intention-to-treat and 34/47 (72%; 95% confidence interval 58-83%) by per-protocol.

CONCLUSION

It seems that performing culture even after a second eradication failure may not be necessary, as it is possible to construct an overall strategy to maximise H. pylori eradication, based on the different possibilities of empirical treatment.

Effect of atmospheric factors on the incidence of Bell's palsy

To assess the possible influence of atmospheric factors on the incidence of Bell's palsy, a retrospective case review of patients seen between 1 January 1992 and 30 June 1996, was designed. The population included all Bell's palsy patients in whom the exact date of onset of paralysis (day, month, year) was known. The following parameters were registered daily by the Spanish National Service of Meteorology throughout the period of survey: temperature, atmospheric pressure and air pollutants (total number of particles and levels of SO2, CO, O3, NO2, NO, CH4 and total organic carbon). The only factor significantly related to Bell's palsy was temperature (P = 0.0164). Lower temperatures were associated with a higher incidence of Bell's palsy. A relationship between atmospheric pressure and/or air pollutants and Bell's palsy was not found.

Optical response to LASIK surgery for myopia from total and corneal aberration measurements

PURPOSE

To evaluate the optical aberrations induced by LASIK refractive surgery for myopia on the anterior surface of the cornea and the entire optical system of the eye.

METHODS

Total and corneal aberrations were measured in a group of 14 eyes (preoperative myopia ranging from -2.5 to -13 D) before and after LASIK surgery. Total aberrations were measured using a laser ray-tracing technique. Corneal aberrations were obtained from corneal elevation maps measured using a corneal system and custom software. Corneal and total wave aberrations were described as Zernike polynomial expansions. Root-mean-square (RMS) wavefront error was used as a global optical quality metric.

RESULTS

Total and corneal aberrations (third-order and higher) showed a statistically significant increase after LASIK myopia surgery, by a factor of 1.92 (total) and 3.72 (corneal), on average. This increase was more pronounced in patients with the highest preoperative myopia. There is a good correlation (r = 0.97, P < 0.0001) between the aberrations induced in the entire optical system and those induced in the anterior corneal surface. However, the anterior corneal spherical aberration increased more than the total spherical aberration, suggesting also a change in the spherical aberration of the posterior corneal surface. Pupil centration and internal optical aberrations, which are not accounted for in corneal topography, play an important role in evaluating individual surgical outcomes.

CONCLUSIONS

Because LASIK surgery induces changes in the anterior corneal surface, most changes in the total aberration pattern can be attributed to changes in the anterior corneal aberrations. However, because of individual interactions of the aberrations in the ocular components, a combination of corneal and total aberration measurements is critical to understanding individual outcomes, and by extension, to designing custom ablation algorithms. This comparison also reveals changes in the internal aberrations, consistent with the posterior corneal changes reported using scanning slit corneal topography.

Investigating sources of variability of monochromatic and transverse chromatic aberrations across eyes

Schematic eye models have typically been used to explain the average monochromatic and chromatic imaging properties of the eye. Both monochromatic aberrations and transverse chromatic aberration are known to vary widely across subjects. However, to our knowledge, the ability of schematic eye models to predict these individual variations has not been tested experimentally. We used a spatially resolved refractometer to measure the monochromatic aberrations and the optical transverse chromatic aberration (oTCA) in a group of 15 eyes. By recording the 1st and 4th Purkinje images for five directions of gaze, we also estimated the tilt, misalignment of ocular surfaces (front surface of the cornea and back surface of the lens) and off-axis position of the fovea (angle alpha), as well as pupil centration. We conclude that, contrary to expectations none of those factors are major contributors to the variability in monochromatic aberrations and oTCA in this group of eyes. Simulations show that corneal curvature and corneal conicity are also unlikely to account for the observed relation between monochromatic aberrations and oTCA. Our results suggest an important contribution of corneal irregularities to those aberrations.