[Anatomical and functional outcomes of vitrectomy for the treatment of pseudophakic regmatogenous retinal detachment]

PURPOSE

To report the results obtained in a non-comparative series of pseudophakic patients with retinal detachment (RD) treated with vitrectomy with no associated scleral procedures.

METHODS

The clinical records of all pseudophakic patients with RD treated with vitrectomy were evaluated by one of the authors. Patients with primary regmatogenous RD with no signs of proliferative vitreoretinopathy were included. Patients with associated ocular pathologies or with less than 3 months follow-up were excluded. Main outcome measures were anatomical reattachment rate after one surgery, visual acuity change and surgical complications. The surgical procedure consisted of 20 g pars plana vitrectomy, with removal of peripheral vitreous up to the ora serrata. Laser photocoagulation of all retinal breaks was performed and 14% C3F8 was used as tamponade.

RESULTS

Thirty-one patients were included in the study. In 18 patients the macula was affected. Mean follow-up was 6.45 months (range 3 to 18). Retinal reattachment was achieved in all patients and only one patient experienced a re-detachment, 3 months after surgery. Visual acuity improved by a mean of 2.5 Snellen lines and 61.3% of patients reached a final visual acuity of 0.5 or better. Eight patients had an intraocular pressure rise after surgery, which was controlled with topical medication. No other complications were recorded.

DISCUSSION

Our results support the hypothesis that vitrectomy alone is a useful technique for the treatment of RD in pseudophakic eyes.

[Evaluation of trypan-blue toxicity in macular hole surgery with electroretinography]

PURPOSE

Concern has been raised about the retinal toxicity of vital dyes. We designed a prospective study to determine the possible toxicity of trypan-blue (TB) in macular hole surgery with TB-assisted internal limiting membrane (ILM) peeling through the performance of electroretinograms (ERGs).

METHODS

Patients diagnosed with a macular hole underwent ophthalmological evaluation prior to surgery and at 6 months follow-up. All patients underwent vitrectomy and ILM-staining under air. All phakic patients underwent phacoemulsification and IOL implantation simultaneously. There were two study groups: In group 1, ILM-staining was performed with 0.06% TB, while in group 2 the procedure was performed with 0.15% TB. Preoperative ERG recordings were measured in the week prior to surgery. Postoperative ERGs were measured 3 to 6 months after surgery. The ERG data between eyes with macular hole and fellow eyes were compared in the pre- and post-operative stages. Visual acuity (VA) changes in both groups were evaluated.

RESULTS

Nine patients were recruited in each group. VA improved significantly in both groups, with more than 65% of patients improving more than 2 lines. There were no statistical differences in VA gain between groups or in ERG values between affected and fellow eyes.

CONCLUSION

No significant retinal toxicity of TB staining could be clinically detected.

[Use of optical coherence tomography to measure prevalence of epiretinal membranes in patients referred for cataract surgery]

PURPOSE

To evaluate, using optical coherence tomography (OCT), the prevalence of epiretinal membranes (ERM) in patients referred for phacoemulsification, and the frequency of new ERM development in the first six months after surgery.

METHODS

Patients referred by general ophthalmologists for cataract surgery underwent a new, complete ophthalmological evaluation. OCT scanning was performed using the Macular Thickness Map acquisition protocol (StratusOCT, Carl Zeiss Meditec). This baseline examination was used to determine the prevalence of ERM in patients referred for cataract surgery. All patients underwent uneventful phacoemulsification. If an ERM was already present in one eye, the other eye was chosen for cataract surgery. If no ERM was present, the eye with the poorest visual acuity was operated. Operated eyes were followed-up for six months in order to study the influence of phacoemulsification on the development of ERM.

RESULTS

Forty-five patients were prospectively evaluated. In the baseline visit, ERM were detected by OCT in 7 patients (15.6%). Both eyes were affected in one patient, with the ERM being apparent on funduscopy only in her left eye. Fundus examination was unremarkable in all other cases. After six months follow-up, no new cases of epiretinal membranes were detected in the eyes that had undergone phacoemulsification, neither by fundus evaluation nor by OCT.

CONCLUSIONS

Epiretinal membranes, previously thought to be secondary to cataract surgery, may be present before phacoemulsification and can be diagnosed by OCT.

[Surgical treatment of Duane's syndrome type I by recession of the medial rectus of the affected eye and faden operation of the contralateral medial rectus]

PURPOSE

Different surgical approaches have been described for the treatment of Duane's syndrome. The purpose of our study is to report the results of patients undergoing recession of the medial rectus (MR) muscle of the affected eye and placement of contralateral MR faden posterior fixation sutures.

METHODS

Retrospective study of 11 patients treated by a 4-7 mm recession of the MR of the affected eye and 13 mm faden posterior fixation suture of the contralateral MR in order to correct abnormal head position and esotropia in primary position.

RESULTS

After surgery, there was no torticolis in 81.8% of patients, with less than 10 degrees of torticolis in the remainder. In all patients, postoperative esotropia was less than 5 prismatic dioptres.

CONCLUSION

This is a safe and effective procedure in Duane's syndrome type I to treat moderate esotropia and torticolis.

[Rebound tonometry in a clinical setting. Comparison with applanation tonometry]

PURPOSE

Rebound tonometry has recently been modified for its use in humans. The purpose of our study was to determine the precision of the ICare(R) rebound tonometer (RBT) as compared with the Goldmann applanation tonometer (GAT).

METHODS

Patients were recruited from our Hospital's Glaucoma Unit. In each patient, intraocular pressure (IOP) was measured without anaesthesia using the RBT and ten minutes later using the GAT. Central corneal thickness (CCT) was measured by pachymetry.

RESULTS

Sixty-eight patients were recruited (132 eyes). Mean IOP readings with RBT were 18.9 +/- 7.2 (SD) mmHg and were 15.5 +/- 5.7 mmHg with GAT (p<0.001). There was a good correlation between both instruments (r = 0.87, p<0.001). In most cases (84.6%) the IOP measured with the RBT was greater than that measured with the GAT. The mean difference between both instruments was 3.4 +/- 3.6 mmHg. There was a trend towards greater differences between those obtained using the RBT than the GAT when IOP values were higher. A statistically significant correlation was found between IOP readings with both tonometers and CCT, with higher differences being seen as the CCT increased.

CONCLUSION

The RBT can be employed in a clinical setting taking into account that it usually overestimates IOP as compared with the GAT. It could be especially useful in glaucoma screening campaigns since it can be operated by a trained technician.

[Plasma concentrations of beta-endorphins in the children of alcoholic patients]

BACKGROUND

Of the factors identified in different studies as the possible causes of alcoholism, heredity appears to be the most important. However, environmental factors can increase or decrease the risk of an individual developing alcohol dependence.

METHOD

To clarify the possible influence of heredity on alcoholism, we studied the plasma concentration of beta-endorphins in 25 families with alcoholic members: 27 children whose father was alcoholic and 7 whose father and mother were both alcoholics. The results were compared with finding in an age-matched control group of no-drinking adults and normal children in non-drinking families.

RESULTS

The children of alcoholic parents had significantly lower beta-endorphin levels (p < 0.001) than control individuals, and concentrations were especially low when both parents were alcoholics.

CONCLUSION

We conclude that plasma beta-endorphin concentration may have predictive value in identifying persons likely to become alcoholics.

Effects of Breed on Follicular Dynamics and Oestradiol Secretion during the Follicular Phase in Sheep

Current study evaluates effects from breed and management background on follicular dynamics and endocrine output during the follicular phase of sheep oestrous cycle. Follicular phases were synchronized with three cloprostenol doses, 10 days apart, in three groups of 10 females of different non-prolific Spanish breeds (Manchega, Rubia del Molar and Negra de Colmenar). Development of all follicles reaching antral diameters >or=2 mm was assessed by daily transrectal ultrasonographies, whereas follicular function was evaluated by measurement of plasma oestradiol concentrations. All the ovulatory follicles were present at induced luteolysis in Manchega sheep, while a 93.7% were detected in Rubia del Molar and Negra de Colmenar ewes. The mean size of these ovulatory follicles was similar between breeds at 0 h, but their growth rates were higher in Manchega ewes, reaching a larger size at oestrous detection than in Negra de Colmenar and Rubia del Molar sheep (p < 0.05). Conversely, the oestradiol levels increased with time in Rubia del Molar and Negra de Colmenar (p < 0.05); whilst remained stable in Manchega females. However, the patterns of follicular turnover were similar between breeds. These results indicate that, though differences in follicular size and size distribution, patterns of follicular turnover in sheep are affected neither by the breed nor by the background of management and selection.

[Apical orbital inflammation in giant cell arteritis]

CASE REPORT

Our purpose is to describe a case of an acute optic neuropathy with apical muscle thickening in a patient already diagnosed with giant cell arteritis. Loss of visual acuity and perimetric concentric constriction responded rapidly to intravenous glucocorticoid therapy. There has been no relapse during continued long-term therapy with cyclophosphamide.

DISCUSSION

Giant cell arteritis is a systemic, idiopathic vasculitis; among its less frequent complications is orbital pseudotumor. Our patient required urgent treatment to avoid visual acuity loss due to compressive neuropathy and perineuritis.

[Ultrasound biomicroscopy in deep sclerectomy with a new acrylic implant]

OBJECTIVE

To describe the ultrasound biomicroscopic (UBM) characteristics seen in patients who have undergone deep phaco-sclerectomy with a new acrylic implant (Esnoper).

SUBJECTS, MATERIAL AND METHODS

UBM exploration was performed 12 months after deep phaco-sclerectomy in three patients with chronic open angle glaucoma.

RESULTS

One year after surgery, all three patients had intraocular pressure levels under 15 mmHg and were on no treatment. All of them had an intrascleral space in UBM, in which the hyperechogenic implant was visible.

CONCLUSIONS

The new non-absorbable implant has proven to be effective in these cases. Information provided by UBM is useful and assists in understanding the mechanism of action of deep sclerectomy.

[Side-effects of triamcinolone in young patients]

CASE REPORTS

Intravitreal triamcinolone is being increasingly employed for the treatment of macular diseases. We report two cases of intraocular pressure elevation and cataract formation after intravitreal triamcinolone therapy, and wonder if these complications are more likely when this agent is used in young patients. Intravitreal triamcinolone was injected into both eyes of the two young patients with chronic posterior and intermediate uveitis refractory to peribulbar and oral corticosteroid therapy. Chronic cystoid macular edema improved in both patients, however the intraocular pressure increased, requiring topical antihypertensive therapy, and this was followed by accelerated cataract formation.

DISCUSSION

Young age and chronic inflammation could be associated with an intraocular pressure rise and subsequent cataract development after intravitreal triamcinolone.

New ways to look at an old problem

A 32-year-old man presented with optic neuritis (papillitis). A discussion of optic neuritis, the role of magnetic resonance imaging, and possible treatment options are presented. The role of optical coherence tomography in following patients with optic neuritis is discussed.

Effects of breed on kinetics of ovine FSH and ovarian response in superovulated sheep

Embryo production is a useful tool for ex situ conservation of endangered species and breeds, despite a high variability in the ovarian response to superovulatory treatments. The current study evaluated the incidence and mechanisms of genetic factors in such variability, by determining the pharmacokinetics and pharmacodynamics of a standard treatment with ovine FSH (oFSH) in two endangered Spanish sheep breeds (Rubia del Molar, R, and Negra de Colmenar, N) in comparison to Manchega ewes (M, control group). In the first experiment, pharmacokinetics of an i.m. single dose of 1.32 mg of oFSH was evaluated in seven animals of each breed. Plasma FSH concentrations reached their maximum at 4h post-administration in all the ewes, but several of the kinetic parameters (plasma FSH concentration at 4h post-administration, maximum plasma FSH concentration, C(max), and both the area under the plasma concentration-time curve extrapolated to the infinite, AUC(inf), and to the last moment of sampling, AUC(last)) were higher in the N group. In the second trial, 10 animals of each breed were superovulated using eight decreasing doses of oFSH (3 x 1.32 mg, 2 x 1.10 mg, and 3 x 0.88 mg). The R group, when compared to N and M, showed both a higher number of corpora lutea (13.7+/-0.6 versus 10.0+/-0.4 in N and 9.8+/-0.6 in M, P<0.05 for both) and embryos (7.9+/-0.8 versus 4.3+/-0.4 in N, P<0.05, and 6.7+/-0.5 in M, n.s.). Evaluation of pharmacokinetic and dynamic parameters showed that, although there was a trend for a higher hormone availability in R sheep, mean FSH plasma concentrations were similar between breeds (0.54+/-0.08 ng/ml for R, 0.45+/-0.05 ng/ml for N and 0.35+/-0.05 ng/ml for M). However, differences were found in the number of preovulatory follicles growing in response to the FSH treatment between R (24.4+/-2.2), M (18.9+/-1.5, n.s.) and N sheep (14.1+/-1.4; P<0.01). Thus, differences in embryo yields between breeds would be related to differences in the pattern of follicular growth in response to FSH treatment.

A comparison between Humphrey and frequency doubling perimetry for chiasmal visual field defects

PURPOSE

To evaluate and compare the diagnostic ability of frequency doubling technology perimetry (FDT) with standard automated perimetry (SAP) using Humphrey Field Analyser for the detection of visual field defects produced by chiasmal lesions.

METHODS

Fifteen patients with documented chiasmal disease and previously diagnosed of bitemporal hemianopia with Humphrey perimetry were prospectively evaluated. All of them underwent a new SAP (SITA 24-2) followed by FDT tests (C-20 threshold). Diagnostic criteria for hemianopia were established according to the total deviation plot and the threshold values of FDT. A patient was diagnosed with hemianopia if one or both criteria were met. Based on these criteria, FDT sensitivity was calculated. Testing time and global indexes for both perimetric strategies were compared.

RESULTS

The sensitivity of FDT was 75.0% (18 out of 24 eyes); the criterion based on threshold values was met more often (70.83%) than the criterion based on the total deviation plot (50.0%). Linear correlation was better for the external column than for the internal column of the visual field. Testing time with FDT was 122.16 seconds shorter than with SAP (p<0.001). The mean value for mean deviation (MD) was -13.62 dB (SD 6.88) for SAP and -8.83 dB (SD 5.94) for FDT (p<0.001).

CONCLUSIONS

Compared with standard automatic perimetry, FDT has a low sensitivity for detecting temporal hemianopias and also has more difficulty in defining the vertical limits of the defects. Therefore, it does not appear to be an adequate method for the detection of chiasmal visual field defects.

Genetic analysis of antibiotic-resistance determinants in multidrug-resistant Shigella strains isolated from Chilean children

A total of 162 clinical isolates of Shigella collected from children in a semi-rural community of Chile were examined for the presence of genetic determinants of resistance to ampicillin, chloramphenicol, tetracycline, and trimethoprim. Ampicillin resistance was most frequently associated with the presence of bla(OXA) in S. flexneri and with bla(TEM) in S. sonnei. The bla(OXA) gene but not bla(TEM) was located in class 1 integrons. The dhfrIa gene encoding for resistance to trimethoprim was associated to class 2 integrons and detected exclusively in S. flexneri, whereas dhfrIIIc was found in all S. sonnei strains and in 10% of the S. flexneri isolates. Cat, coding for choramphenicol resistance, and bla(OXA) genes were located in the chromosome in all cases, whereas tetA gene, coding for tetracycline resistance, and bla(TEM), dhfrIa and dhfrIIIc genes were found either in the chromosome or in conjugative plasmids. Our results show a heterogenous distribution of antibiotic-resistance determinants between S. flexneri and S. sonnei.

[Utility of bronchoalveolar lavage in immunocompromised children: diagnostic yield and complications]

OBJECTIVE

Immunocompromised children are at high risk for developing pneumonia due to opportunistic pathogens. The role of bronchoalveolar lavage (BAL) in the evaluation of such patients is still controversial.

MATERIAL AND METHOD

We reviewed the hospital records of immunosuppressed patients with respiratory symptoms who had undergone BAL in the pediatric department of the Hospital Clinico de la Pontificia Universidad Católica of Chile.

RESULTS

Sixty-eight BAL were performed on 54 children (mean age: 7.5 years) receiving wide-spectrum antibiotic treatment. The most frequent respiratory signs and symptoms were fever (90%) and cough and respiratory distress (81%); 18% had neutropenia and 43% thrombocytopenia. A specific pathogen was identified in BAL samples for 25 patients (37%). The pathogens isolated were bacteria in 21 cases, viruses in 6, Pneumocystis carinii in 5, fungi in 4, and Mycobacterium tuberculosis in one. Fourteen (19%) of the children who underwent BAL were on mechanical ventilation. Outcome was satisfactory in all cases. Twenty-one complications were recorded, 17 of which were minor (mild hypoxemia or fever) and 4 major, requiring tracheal intubation. No deaths were recorded.

CONCLUSIONS

Evaluation by fiberoptic bronchoscopy together with BAL proved to be a safe procedure with an adequate diagnostic yield that made it possible to determine the etiology of the pulmonary infiltrates seen in chest x-rays. Both positive and negative results of BAL were useful for treating the patients.

[IOP spikes following contact transscleral diode laser cyclophotocoagulation]

PURPOSE

To evaluate the incidence of intraocular pressure (IOP) spikes after contact transscleral diode laser cyclophotocoagulation (cyclodiode) and to identify related risk factors.

METHOD

Retrospective study of 116 eyes (110 patients) with refractory glaucoma who underwent cyclodiode. IOP measurement was obtained immediately before and one hour after cyclodiode. We defined an IOP spike as an increase equal or superior to 5 mmHg after laser treatment. We evaluated several potential pre-, intra- and post-operative factors related to the IOP spike occurrence.

RESULTS

Mean IOP decreased one hour after cyclodiode 6.96 mmHg (SD: 8.36) (p<0.001). Overall, we observed 10.8% of IOP spikes. Age, sex, mean energy delivered, pop occurrence and iris colour were not associated with the postoperative IOP spike occurrence. The percentage of IOP spikes was higher in neovascular glaucoma (p=0.074). The IOP spike rate was also higher after retreatment, but the difference compared to the eyes which underwent cyclodiode for the first time was not significant.

CONCLUSIONS

These preliminary results suggest that IOP spike prevention could be considered in neovascular glaucoma scheduled for cyclodiode

Epithelial cell contact-induced alterations in Salmonella enterica serovar Typhi lipopolysaccharide are critical for bacterial internalization

The invasion of Pseudomonas aeruginosa and Salmonella enterica serovar Typhi into epithelial cells depends on the cystic fibrosis transmembrane conductance regulator (CFTR) protein as an epithelial receptor. In the case of P. aeruginosa, the bacterial ligand for CFTR is the outer core oligosaccharide portion of the lipopolysaccharide (LPS). To determine whether serovar Typhi LPS is also a bacterial ligand mediating internalization, we used both P. aeruginosa and serovar Typhi LPS as a competitive inhibitor of serovar Typhi invasion into the epithelial cell line T84. P. aeruginosa LPS containing a complete core efficiently inhibited serovar Typhi invasion. However, neither killed wild-type Typhi cells nor purified LPS were effective inhibitors. LPS from mutant Typhi strains defective in O side-chain synthesis, but with an apparently normal core, was capable of inhibiting invasion, but LPS obtained from a deeper rough mutant strain with alterations in fast-migrating core oligosaccharide failed to inhibit invasion. Lastly, exposure of wild-type serovar Typhi to T84 cultures before heat killing resulted in a structural alteration in its LPS that allowed the heat-killed cells to inhibit invasion of wild-type serovar Typhi. These data indicate that the serovar Typhi LPS core, like the P. aeruginosa LPS core, is a ligand mediating internalization of bacteria by epithelial cells, and that exposure of this ligand on wild-type Typhi is induced by the bacteria's interaction with host cells.

The rfaH gene, which affects lipopolysaccharide synthesis in Salmonella enterica serovar Typhi, is differentially expressed during the bacterial growth phase

We have cloned and sequenced the rfaH gene from Salmonella enterica serovar Typhi strain Ty2. The gene showed a high degree of similarity to the rfaH genes from Escherichia coli K-12 and S. enterica serovar Typhimurium. A rfaH mutant was constructed by site-directed mutagenesis. This mutant produced a rough lipopolysaccharide (LPS), with an incomplete core region. The defect in LPS expression that results from the rfaH mutation was corrected by a plasmid carrying the intact gene. The plasmid-borne rfaH gene also restored normal LPS synthesis in a rfaH mutant of E. coli. Reverse transcription-polymerase chain reaction analyses were performed to determine the effects of various environmental conditions on the expression of rfaH. The transcription of rfaH showed a growth-phase-dependent regulation, with maximal expression at the late exponential phase. Other environmental conditions, such as temperature or medium osmolarity, did not affect transcription of rfaH.

Uptake of endocytic markers by rice cells: variations related to the growth phase

Endocytosis is now considered a basic cellular process common to plant cells. Although both non-specific and receptor-mediated endocytosis appear to take place in plant cells, the physiological role of the latter remains unclear. We have investigated the endocytic process in rice cell suspensions using two biotinylated proteins, peroxidase and bovine serum albumin (bHRP and bBSA), as markers. First, we show that markers are internalized by rice cells and appear in intracellular membranes. The uptake of the two markers is temperature dependent, saturable with time and markers dose and it is competed by free biotin. Thus, it shows the properties of a receptor-mediated process. We also show that uptake of markers is strongly influenced by growth phase as optimal uptake occurs during the lag phase, but the initiation of the exponential growth phase decreases uptake drastically. Arrest of the cell cycle by starvation of either a nutrient (phosphate) or a growth regulator (2,4-dichlorophenoxyacetic acid), both components of the culture medium, does not modify the rate of bBSA uptake. Subsequent readdition of these components results in growth recovery and a dramatic decrease in bBSA uptake. On the other hand, nocodazole treatment, a method to arrest the cell cycle by microtubule depolymerization, inhibited bBSA uptake. The possible causes for this arrest of endocytosis are discussed.

Estrogen replacement therapy and the prevention of coronary heart disease in postmenopausal women

The use of estrogen replacement therapy (ERT) for the prevention of coronary heart disease (CHD) is discussed. Cardiovascular disease is the number one cause of death in women. It is believed that the loss of estradiol production at menopause increases the risk of CHD. Theoretically, ERT should decrease CHD risk in postmenopausal women by maintaining at premenopausal levels the metabolic factors that affect CHD. Many mechanistic studies of the effects of estrogen on lipoproteins, hemostasis, carbohydrate metabolism, and vessel wall tone and reactivity support a cardioprotective role for estrogen. In addition, observational studies have found that ERT, with or without progesterone, significantly reduces the risk of CHD. However, mechanistic and observational studies can establish only an association, not a cause-and-effect relationship. Furthermore, bias may influence the risk estimates. The Heart and Estrogen/Progestin Replacement Study (HERS), published in 1998, was the first large, randomized, controlled trial to evaluate the efficacy of estrogen and progesterone replacement therapy in reducing CHD risk. Overall, the study found that continuous hormone replacement therapy (HRT) in women with CHD did not reduce cardiovascular risk at an average of 4.1 years of follow-up. In addition, there was an early increase in the risk of thromboembolic events. Although many mechanistic and observational studies suggest that ERT reduces the risk of morbidity and mortality from CHD in postmenopausal women, the only large, randomized, controlled study of this question to date failed to confirm this. Until data from ongoing studies are available, health care providers must reconsider prescribing ERT or HRT solely for the secondary prevention of CHD.

Characterization of Cop I coat proteins in plant cells

Membrane traffic in eukaryotic cells is mediated by COP (coat protein)-coated vesicles. Their existence in plant cells has not yet been unequivocally demonstrated, although coated vesicles (probably with a COP coat) can be seen by electron microscopy. At the gene level, plant cells seem to contain all the components necessary to form COP-coated vesicles. In this paper, we have used antibodies raised against mammalian COPI coat proteins to detect putative homologues in rice (Oryza sativa) cells. Using these antibodies, we have found that rice cells contain alpha-, beta-, beta'-, and gamma-COP, as well as ADP-ribosylation factor (ARF) 1 protein. In addition, we show that antibodies against mammalian beta'-COP can immunoprecipitate not only beta'-COP but also alpha-, beta-, and gamma-COP, suggesting that COPI components in rice cells exist as a complex (or coatomer) in the cytosol, as in mammalian cells. Finally, we show that COP binding to membranes is GTP-dependent, and that ARF1 also binds to membranes in a GTP-dependent manner.