[Therapy refractory unilateral chronic blepharokeratoconjunctivitis as the chief manifestation of auto-aggression syndrome. Clinico-histopathologic findings]

Autoaggressive syndromes as causes of diseases underlying chronic blepharitis and keratoconjunctivitis that are refractory to treatment are often difficult to recognize.

PATIENTS

Three female patients (age 21, 25, 41 years) and one male patient (age 42 years) had suffered from a right-(4x) or left-(1x) handed treatment-refractory blepharokeratoconjunctivitis for 1, 2, 11 and 30 months prior to admission. In each case more than 5 ophthalmologists and 2-6 eye hospitals had been consulted, and extraocular surgery had been performed 1-4 times.

RESULTS

Patients presented with a visual acuity of 0.3 p (1x), 0.1 (1x), FC (1x), HM (1x). In three patients contact eczema of the facial skin and lids and a corneal pannus were observed; in two patients we saw purulent pseudomembranous and in two patients chronic cicatrizing keratoconjunctivitis. Conjunctival smears grew P. aeruginosa, and S. aureus; impression cytology showed infiltration with neutrophils and epithelial keratinization; histopathology indicated chronic inflammatory, partly purulent subepithelial and stromal conjunctival infiltrate with hyper- and parakeratosis fibrous strands and epithelial cell loss; the lower lids showed parakeratosis, focal necrosis, intercellular edema and a lymphohistiocytic round-cell infiltrate. Furthermore, multiple allergies to antibiotics and preservatives (4x), lacerations of the arms and legs (2x) and an irritative-toxic dermatitis (1x) were substantiated. In the patients who agreed to a psychiatric consultation, somatized-agitated longing for care combined with a dependent and infantile personality (1x) and reactive depression (2x) were verified.

CONCLUSIONS

In patients suffering from treatment-refractory unilateral chronic blepharokeratoconjunctivitis correlated with the hand, one must take into consideration the fact that other factors may be involved: possible exacerbation prior to examinations; multiple inpatient diagnostic and surgical procedures in different locations; histopathological mixed inflammatory patterns; and psychiatric syndromes.

Treatment of retinal arterial occlusion with local fibrinolysis using recombinant tissue plasminogen activator

OBJECTIVE

Retinal arterial occlusion is one of the most dramatic problems faced by ophthalmologists because of its sudden onset and the severe consequences it may have on the visual system. In this study, local intra-arterial fibrinolysis (LIF) using recombinant tissue plasminogen activator (rTPA) as a new technique for the treatment of retinal arterial occlusion was investigated.

DESIGN

Retrospective, noncomparative case series.

PARTICIPANTS

Strict inclusion and exclusion criteria were used to select patients for treatment. Fifty-three patients with central retinal artery occlusion (n = 46) or branch retinal arterial occlusion (n = 7) were enrolled.

INTERVENTION

For a maximum of 3 hours, 10- to 20-mg rTPA per hour in 50-ml sodium chloride was infused transfemorally by catheterization of the ophthalmic artery with a variable stiffness microcatheter.

MAIN OUTCOME MEASURES

The best-corrected visual acuity for distance by an 18-line logarithmic table was measured on admission, at 24 hours, and at 3 months after intervention.

RESULTS

At 3 months, visual acuity had improved in 35 (66%) of 53 patients. Twenty-five (47.2%) patients showed an improvement of more than 2 lines, and in 10 (18.8%) patients, improvements of 1 to 2 lines were observed. No change in visual acuity occurred in 12 (22.6%) patients, and in 6 (11.3%) patients, the visual acuity deteriorated. The mean occlusion time was 14 hours (range, 3-50 hours). No statistically significant correlation was found between occlusion time and visual outcome (P > 0.22). In two patients, a temporary slight hemiplegia was observed during catheterization, and in one patient, a hypertensive crisis after LIF treatment was observed.

CONCLUSIONS

The high success rate of LIF using rTPA in patients suffering from retinal arterial occlusion is supposedly due to a causal effect of rTPA on primary platelet-fibrin emboli and secondary thrombi. The local fibrinolytic therapy with rTPA involves little risk for patients selected by strict inclusion and exclusion criteria. It may be used for the treatment of retinal arterial occlusion even later than 8 hours after the acute visual loss. However, a successful outcome of the therapy depends on the prompt referral by well-informed ophthalmologists; a speedy execution of all internal, neurologic, and ophthalmologic diagnostic measures; and a prompt therapy.

A randomized trial of short-course ciprofloxacin, ofloxacin, or trimethoprim/sulfamethoxazole for the treatment of acute urinary tract infection in women. Ciprofloxacin Urinary Tract Infection Group

PURPOSE

Bladder infections are very common in otherwise healthy women, and short-course antimicrobial treatment appears effective for many episodes of cystitis. This study reports the results of short-course ciprofloxacin, ofloxacin, and trimethoprim/sulfamethoxazole therapy.

PATIENTS AND METHODS

We performed a randomized, double-blind study of the efficacy and safety of a 3-day course of oral ciprofloxacin 100 mg twice daily, ofloxacin 200 mg twice daily, or trimethoprim/sulfamethoxazole 160/800 mg twice daily in women with acute, uncomplicated, symptomatic lower urinary tract infection.

RESULTS

A total of 866 patients were enrolled, of whom 688 (79%) were evaluated for the efficacy of treatment (229 treated with ciprofloxacin, 228 treated with trimethoprim/sulfamethoxazole, and 231 treated with ofloxacin). The most frequent reason for exclusion was the failure to identify a pretreatment pathogen. The most commonly isolated pathogen was Escherichia coli (81%). Eradication of the pretreatment pathogen at the end of therapy occurred in 94% of ciprofloxacin, 93% of trimethoprim/sulfamethoxazole, and 97% of ofloxacin-treated patients. At follow-up evaluation at 4 to 6 weeks, recurrence rates (relapse or reinfection) were 11% in the ciprofloxacin, 16% in the trimethoprim/sulfamethoxazole, and 13% in the ofloxacin treatment group. Clinical success at the end of therapy was 93% in the ciprofloxacin, 95% in the trimethoprim/sulfamethoxazole, and 96% in the ofloxacin treatment groups. The frequency of all adverse events was 31% for ciprofloxacin, 41% for trimethoprim/sulfamethoxazole, and 39% for ofloxacin-treated patients (P = 0.03). Premature discontinuation of study drug due to an adverse event was more common in trimethoprim/sulfamethoxazole-treated patients (n = 9) compared with those given ciprofloxacin (n = 2) or ofloxacin (n = 1; P = 0.02).

CONCLUSION

Ciprofloxacin, ofloxacin, and trimethoprim/sulfamethoxazole had similar efficacy when given for 3 days to treat acute, symptomatic, uncomplicated lower urinary tract infection in women.

[Immunohistochemical characterisation of surgically excised choroidal neovascularisation in age-related macular degeneration]

AIM

The objective of the study was to gather further information about the pathogenesis of choroidal neovascularisations (CNV), which is still not clearly understood, and to establish criteria for making decisions on a appropriate therapy. Immunohistochemical characteristation should allow a more comprehensive evaluation of cellular components of the membranes and their functional role.

PATIENTS AND METHODS

In 29 patients (16 women, 13 men) with age-related macular degeneration ranging in age from 46 to 91 years (mean age, 76.4 years), CNV were excised by pars-plana vitrectomy. Sections were stained with hematoxylin-eosin (HE) and periodic acid-Schiff (PAS) and examined by light microscopy. For the immunohistochemical characterisation of the surgical specimens the following anti-genetic determinants were used: glial fibrillary acid protein (GFAP) for glial cells, synaptophysin for neuronal cells, neuron-specific enolase (NSE) for neuronal and neuroectodermal cells, CD 31 for endothelial cells and pancytokeratin (KL1) for cells of the retinal pigment epithelium (RPE). Cells undergoing apoptosis were labeled with the TUNEL technique.

RESULTS

22 (76%) surgical specimens showed TUNEL positive cells in the connective tissue, vascular endothelium and retinal pigment epithelium. Positive immunostaining of neuronal antigenetic determinants was found for glial fibrillary acid protein in 22 patients (76%), for synaptophysin in 28 patients (97%) and for neuron-specific enolase in 21 patients (72%) CNV. The epithelial marker KL1 was positive in 28 patients (97%) and the endothelial marker CD 31 in 20 patients (69%).

CONCLUSION

The immunohistochemical analyses of CNV showed that in the majority of cases during the excision of choroidal neovascularizations in addition to scar tissue and connective tissue also parts of the native retinal pigment epithelium and of the neurosensory retina are removed which is only partly visible with standard staining techniques. These findings suggest that the mostly not satisfying postoperative results are partly due to the damage of neuronal cells and a partial loss of the retinal pigment epithelium. Apoptosis as a regulating mechanism in choroidal neovascularization. The variable appearence of apoptosis suggests that it is possibly related to the degree of activity of CNV.

[Conus venoms: a source of toxins which interact with membrane- potential-dependent sodium channels]

Marine snails of the genus Conus, as they are carnivorous predators, have a venom apparatus used to capture their prey. The toxins contained in the venoms of Conidae, called conotoxins, are of a particular high degree of diversity and represent powerful tools in the neuroscience field. Indeed, these toxins specifically bind with a high affinity to receptors and ionic channels. Therefore, they provide original pharmacological tools which receive increasing investigation both to identify and study some functions of the nervous systems and to characterize new types and closely related subtypes of receptors or ionic channels. The voltage-gated sodium channel, because of its fundamental role in cell membrane excitability, is the specific target of a large number of animal and vegetal toxins. Actually, at least seven toxin receptor sites have been identified on this channel-protein. These toxins, and in particular conotoxins, are used to precise the role of different types and/or closely related subtypes of sodium channels in the peripheral and central nervous systems. The focus of the present review is to summarize our current knowledge of the consequences of physiological interactions between different conotoxin families and sodium channels.

[Severe ocular injuries caused by fishing equipment]

BACKGROUND

Severe ocular injuries due to fishing equipment are rare, almost exclusively involve the anterior segments of men, and bear a bad prognosis. We report on two men and one woman with different etiologies of accidents.

PATIENTS

In two men (53 and 39 yrs. OD and OS) and one woman (27 yrs., OD) a choroidal rupture due to a lead weight and subsequent choroidal neovascularisation (1x), temporal and nasal scleral and retinal lacerations (2x) due to a fish pick and a fish hook were noted. A laceration of the m. rectus int. (1x), uveal and retinal prolapse (1x), traumatic aniridia and aphakia (1x), a 12 and a 15 mm corneoscleral perforation temporal and nasal resp. including a retinal incarceration, a giant retinal tear 270 degrees, and vitreous and subretinal hemorrhage were seen.

SURGERY

Interventions included 2x tight wound closure, 3x ppv, retinotomies (1x) endolasercoagulation (3x), silicone oil instillation (3x), muscel refixation (1x), and posterior lens implantation (1x). Subsequent surgery were silicone oil removal (2x) and membrane peeling (1x).

RESULTS

An anatomical reconstruction was achieved in all of the patients, and the best postoperative visual acuity was gained after 4-6 months (+6.0 sph (2x) = 0.5, and +4.0 sph (1x) = 0.3). Silicone oil was removed after 4 and 13 months resp. followed by hypotony and redetachments, in one patient with silicone oil in place vision remained stable for > 2 years up to now at 0.5.

CONCLUSIONS

Accidents due to fishing equipment may result in lacerations and contusions and involve women as well as. Surgery for extensive lacerations and complications of choroidal ruptures may not be hopeless, however, the prognosis for subsequent interventions is not good. Indications to remove silicone oil in eyes bearing a relative ciliary body insufficiency due to a long-standing insufficient wound closure should be done very cautiously.

Mutations in the human connexin gene GJB3 cause erythrokeratodermia variabilis

Erythrokeratodermia variabilis (EKV, OMIM 133200) is an autosomal dominant genodermatosis with considerable intra- and interfamilial variability. It has a disfiguring phenotype characterized by the independent occurrence of two morphologic features: transient figurate red patches and localized or generalized hyperkeratosis. Both features can be triggered by external factors such as trauma to the skin. After initial linkage to the RH locus on 1p, EKV was mapped to an interval of 2.6 cM on 1p34-p35, and a candidate gene (GJA4) encoding the gap junction protein alpha-4 (connexin 31, Cx31) was excluded by sequence analysis. Evidence in mouse suggesting that the EKV region harbours a cluster of epidermally expressed connexin genes led us to characterize the human homologues of GJB3 (encoding Cx31) and GJB5 (encoding Cx31.1). GJB3, GJB5 and GJA4 were localized to a 1.1-Mb YAC in the candidate interval. We detected heterozygous missense mutations in GJB3 in four EKV families leading to substitution of a conserved glycine by charged residues (G12R and G12D), or change of a cysteine (C86S). These mutations are predicted to interfere with normal Cx31 structure and function, possibly due to a dominant inhibitory effect. Our results implicate Cx31 in the pathogenesis of EKV, and provide evidence that intercellular communication mediated by Cx31 is crucial for epidermal differentiation and response to external factors.

[Clinical and histopathological aspects of 113 necrotizing malignant melanomas of the choroid. 1. Clinical and histological features of necrotizing choroidal melanomas]

BACKGROUND

Tumor necrosis may reflect a destructive immune reaction. Systematic and statistically significant comparative clinico-histopathologic studies have not yet been reported.

PATIENTS AND METHODS

113 necrotizing choroidal melanomas (NCM) recruited from 701 enucleated globes 1967-1988 were resectioned, stained and compared to 100 choroidal melanomas without necrosis (CM), and data of 74 patients with a follow-up of more than 10 years were evaluated.

RESULTS

Statistically significant characteristics of NCM were: patient age < 60 yrs. for NCM 27.4%, CM 46%; patient age in men for NCM was 64 yrs on average (CM: 58 yrs.), in women for NCM 67 yrs. (CM: 59 yrs.). Time elapsed between first symptoms and enucleation was < 12 months in 15.9% of NCM (89% for CM), and > 12 months in 23.9% of NCM (11% in CM). Mixed or epitheloid cell tumors was seen in 54.9% of NCM and 49% of CM, spindle cell tumors in 36.3% of NCM and 51% in CM. Advanced tumor stages T3 and T4 were present in 45.1% resp. 36.3% of NCM compared to 37% resp. 16% in CM. Scleral invasion was documented in 67.3% of NCM and 37% of CM, extrascleral dissemination in 43% of NCM and 16% of CM. Secondary glaucomas were seen in 62.2% of NCM and 6% CM, a penetration through Bruch's membrane in 61.0% of NCM and 46% of CM. Intratumoral hemorrhage was noted in 68.14% of NCM and 24% of CM, extratumoral bleeding in 23.9% of NCM and 0% CM. Inflammatory reactions in tumors were observed in 96.7% of NCM harboring > 30% necrosis compared to 5% in CM, and extratumoral in 94.5% of NCM and 0% of CM. Intraocular extratumoral necrosis was seen in 23.9% of NCM and 0% of CM. There were no significant differences in the degree of pigmentation of the 90.3% pigmented NCM or of the 94% pigmented CM, neither in the tumor localization, being constantly behind the equator in 87% of cases. Survival of patients with NCM patients was 5 years and 9 months on average (5-year mortality rate 41.9%), and 74.3% were deceased from metastatic spread.

CONCLUSIONS

Significant clinical and histopathological differences between necrotizing and non-necrotizing malignant melanomas of the choroid can be identified. The inflammatory reaction of NCM must be further elucidated, particularly with respect to the nature of tumor-infiltrating lymphocytes.

[Clinical and histopathological aspects of 113 necrotizing malignant melanomas of the choroid. 2. Immunogenetic characterization of T-cell receptor-positive tumor-infiltrating lymphocytes and survival of patients with necrotizing melanomas of the choroid]

BACKGROUND

T-cell receptor (TCR) gene analysis of tumor infiltrating lymphocytes (TIL) has been recognized to play a pivotal role in the immunosurveillance of solid neoplasms.

PATIENTS AND METHODS

Therefore, 113 necrotizing choroidal melanomas (NMM) were compared to 100 non-necrotizing melanomas (MM) histologically and immunohistochemically.

RESULTS

NMM showed TIL more frequently (76.11% vs. 21%, p < 0.001). V alpha/V beta- (70.3% of NMM) and V gamma 1- (39.2% of NMM) and V delta 1- (52.7% of NMM) TCR+ cells were distributed focal or diffuse, and correlated with tumor volume, diameter, and scleral invasion. 74.33% of NMM patients had died after 240 months (5 year survival: 58.1%). Mortality was not significantly associated with TIL (p < 0.33) or V alpha/V beta-TCR+ cells (p < 0.2), however, survival was significantly increased with evidence of V gamma 1- and V delta 1-TCR+ cells (p < 0.026).

CONCLUSIONS

V alpha/V beta-, V gamma 1- and V delta 1-TCR+ tumor infiltrating lymphocytes can be demonstrated in choroidal melanomas. This is a basis for functional studies providing a rationale for the evaluation of immunotherapeutic modalities.

Endothelial cell loss secondary to two different phacoemulsification techniques

BACKGROUND AND OBJECTIVE

The endothelial cell count after phacoemulsification serves as a sensitive indicator for the level of corneal damage caused by different phacoemulsification techniques.

PATIENTS AND METHODS

In a prospective and randomized study, the "Reversed Tip and Snip" technique and the "Divide and Conquer" technique were performed in groups of 30 patients each. The corneal endothelial cell count was measured preoperatively as well as 4 weeks and 3 months postoperatively.

RESULTS

The endothelial cell count showed significant (P < .001) reduction by approximately 10% after the "Reversed Tip and Snip" technique and by approximately 15% (P < .001) after the "Divide and Conquer" technique. The latter produced a significantly (P < .001) greater cell loss.

CONCLUSIONS

The "Reversed Tip and Snip" phacoemulsification technique produces less endothelial cell loss than the "Divide and Conquer" technique.

[Immunohistochemical markers for cytoplasmic antigens in acquired melanosis, malignant melanomas, and nevi of the conjunctiva]

BACKGROUND

Benign and malignant melanocytic lesions of the conjunctiva are difficult to differentiate histologically. At present in the ophthalmologic literature there is not known a high specific and simply applicable histological feature (tumor marker) of differentiation to identify melanocytic lesions of the conjunctiva.

METHODS

In this study 55 nevi, 15 primary acquired melanoses (stage Ia) and 54 melanomas of the conjunctiva were examined retrospectively immunhistochemically by antibodies vs. S-100 protein, and the melanoma-associated antigens HMB-45 and NKI/C3 using the labelled avidin-biotin method. 45 patients (25 female, 20 male) with malignant melanomas of the conjunctiva have been followed up clinically.

RESULTS

S-100, HMB-45 and NKI/C3 are highly significant markers to identify malignant melanomas of the conjunctiva (sensitivity: S-100: 96.4%, HMB-45: 96.3%, NKI/C3: 98.1%), whereas markers in acquired melanoses (sensitivity: 93.3%, 78.6% and 92.9%), and nevi (sensitivity: 92.9% 40.7%, 98.2%) are not. Positive tumor markers do not correlate with local recurrences or metastasis. The localization of malignant melanomas and the lymphocytic infiltration are not prognostically significant. The only significant risk factor (p = 0.0485) predicting the development of recurrence or metastasis is tumor thickness > 1.5 mm.

CONCLUSIONS

The tumor markers S-100, HMB-45 and NKI/C3 cannot differentiate reliably between benign and malignant melanocytic lesions of the conjunctiva, and positive tumor markers do not correlate with local recurrences or metastasis. The only significant risk factor (p = 0.0485) predicting the development of metastasis is tumor thickness (> 1.5 mm).

Functional defects of Cx26 resulting from a heterozygous missense mutation in a family with dominant deaf-mutism and palmoplantar keratoderma

Mutations in GJB2 encoding the gap junction protein connexin-26 (Cx26) have been established as the basis of autosomal recessive non-syndromic hearing loss. The involvement of GJB2 in autosomal dominant deafness has also been proposed, although the putative mutation identified in one family with both deafness and palmoplantar keratoderma has recently been suggested to be merely a non-disease associated polymorphism. We have observed a similar phenotype in an Egyptian family that segregated with a heterozygous missense mutation of GJB2, leading to a non-conservative amino acid substitution (R75W). The deleterious dominant-negative effect of R75W on gap channel function was subsequently demonstrated in the paired oocyte expression system. Not only was R75W alone incapable of inducing electrical conductance between adjacent cells, but it almost completely suppressed the activity of co-expressed wildtype protein. The Cx26 mutant W77R, which has been implicated in autosomal recessive deafness, also failed to form functional gap channels by itself but did not significantly interfere with the function of wildtype Cx26. These data provide compelling evidence for the serious functional consequences of Cx26 mutations in dominant and recessive deafness.

[Necrotizing keratitis in chronic polyarthritis. Combined immunosuppressive and surgical therapy]

INTRODUCTION

Areactive forms of keratitis in patients with seropositive rheumatoid arthritis are inflammations threatening the visual acuity and integrity of the eye. They commonly occur in a rheumatologically inactive interval and have a poor prognosis. A retrospective evaluation of medicamentous and surgical strategies for a curative therapy with optical rehabilitation is necessary to optimise the treatment of patients with necrotic sclerokeratitis.

PATIENTS AND METHODS

A total of 27 eyes of 22 patients (14 women and 8 men, ranging in age at the time of operation from 40 to 88 years; mean 68.7 years) with seropositive rheumatoid arthritis and secondary Sjögren's syndrome were reviewed retrospectively. There were 17 eyes with necrotic keratitis and 9 eyes with necrotic sclerokeratitis. In one eye, necrotic sclerokeratitis with bacterial transmigrating keratitis and hypopyon occurred.

OPERATIONS

In 8 cases we performed a perforating mini-keratoplasty, in 16 cases a tectonic and optical perforating keratoplasty, in 3 cases a tectonic sclerokeratoplasty, in 9 patients a combined keratoplasty and cataract extraction with posterior chamber lens implantation and in 1 case a partial conjunctival plasty. Follow-up ranged from 7 months to 4 years (average 2.8 years).

RESULTS

In all eyes, a sufficient tectonic and primary curative effect was achieved only under cyclophosphamide immunosuppression. In 3 cases, a rekeratoplasty had to be performed because of recurrent keratitis after changing the systemic cyclophosphamide therapy to methotrexate, glucocorticosteroids or non-steroid antiphlogistic agents. Visual acuity outcome was depending on the eccentricity of the keratoplasty and earlier affections of the eye. Postoperatively, the visual acuity improved in 23 eyes. In 3 cases, no change of visual acuity was achieved. Visual acuity deteriorated in one case from counting fingers to hand motions. Peri- and postoperative complications during the follow-up period were corneal infiltration around sutures in 4 eyes, graft rejecting reactions in 3 cases, and sicca syndrome in 6 cases.

CONCLUSIONS

The intensive cooperation of ophthalmologists and rheumatologists enables the successful treatment of apparently hopeless situations in necrotic sclerokeratitis in patients with seropositive rheumatoid arthritis. The rate of complications under an immunosuppressive therapy with cyclophosphamide was found at average 2.8 years follow-up to be low. The indication for the combined therapy depends on the ophthalmological findings; rheumatologists and ophthalmologists should decide on the appropriate dosage for the systemic cyclophosphamide therapy. Topical glucocorticosteroid therapy alone is contra-indicated.

[Recurrent pterygium over 15 years: epibulbar cartilaginous findings]

BACKGROUND

Epibulbar and extraocular cartilage bearing tumors in adults are extremely rare.

PATIENT

A nasally located pterygium in a 24-year-old patient was excised and recurred over the ensuing 15 years six times requiring local excisions, and each time a histological diagnosis of pterygium was made. Only a curative excision including a biopsy of the insertion of the m. rectus medialis and a sclerokeratoplasty revealed the tumor to bear cartilage histologically in an unusual place. A Ruthenium-106 brachytherapy was followed by a triple procedure for visual rehabilitation, and no further recurrences were observed.

CONCLUSION

The differential diagnosis of a cartilaginous tumor most likely a choristoma growing in an unusual localisation should be considered in adults suffering from recurrent pterygia without known physical risk factors, and a curative excision be performed. Further treatment options depend on the appearance of the tumor.

Limitations of imaging choroidal tumors in vivo by optical coherence tomography

BACKGROUND

Optical coherence tomography (OCT) produces two-dimensional cross-sectional images with a longitudinal resolution of 10 microns. Its capacity for imaging retinal structure has been shown in a variety of diseases. There are no reports on its capacity and limitations in imaging choriocapillary and choroidal structures.

METHODS

Twenty-two patients with the diagnosis of malignant melanoma of the choroid were submitted to OCT. We used a prototype and a commercial device, both with an 850-nm superluminescent diode with a band-width of 30 nm (reported longitudinal resolution 10 microns). The images were evaluated for retinal thickness, changes in retinal pigment epithelium, subretinal fluid accumulation and changes in choriocapillary or choroidal reflectivity.

RESULTS

Retinal edema and detachment found on biomicroscopic examination for fluorescein angiography was detected by OCT in all such cases. In 2 of 22 cases small retinal detachments were detected only by OCT. Tumor extension through the retinal pigment epithelium was not seen in this series, either by biomicroscopy or by OCT. The pattern of choroidal or choriocapillary reflectivity was nonspecifically lower than that of normal choroid, but did not yield any additional information about tumor histology. When normal retina was present, the OCT appearance of a malignant melanoma resembled that of normal choroid.

CONCLUSION

OCT may provide information about the retinal structure overlying prominent tumors and the extent of adjacent retinal detachment. In its present state of development, OCT is of little value in the differential diagnosis of choroidal tumors. Its potential value for the follow-up of shallow tumors needs further investigation.

[Intraocular pseudotumor in an AIDS patient. Block excision, differential diagnosis, histology]

BACKGROUND

Intraocular pseudotumors are a rare event in Aids patients and often pose diagnostic problems.

CASE REPORT

A 37-year-old patient who had had HIV seroconversion for 7 years was seen to developed progressively growing, multiple, disseminated, subretinal lesions OD > OS, accompanied by exudative retinal detachment and iritis. Since all etiological laboratory diagnostic efforts to detect an infectious, noninfectious and neoplastic systemic lesion failed, a diagnostic and curative therapeutic chorioretinal excisional biopsy specimen of the largest of the tumors (3 x 3 x 2 mm) was taken. The histological work-up demonstrated granulation tissue similar to an intraocular pseudotumor without signs of infection, malignancy or reactive lymphoid hyperplasia. This finding resulted in systemic corticosteroid treatment with complete resolution of the lesions in both eyes and no recurrences.

CONCLUSIONS

An invasive diagnostic procedure in patients suffering from lesions of unknown cause resulting in the institution of an appropriate medical treatment may be beneficial for the integrity and vision of the respective eye.

[Type I lattice corneal dystrophy. Clinical and molecular genetic study of a large family]

BACKGROUND

Lattice corneal dystrophy type I is one of the frequent forms of stromal dystrophies following autosomal dominant inheritance. The beta-IG-h3 gene encoding keratoepithelin on the long arm of chromosome 5 has recently been described as disease gene for lattice corneal dystrophy type I as well as for three other corneal dystrophies with autosomal dominant pattern of inheritance.

PATIENTS AND METHODS

Ten family members in three generations of a large family with autosomal dominant lattice corneal dystrophy were analyzed clinically by slit-lamp biomicroscopy. Mutation analysis in the beta-IG-h3 gene was carried out at the mRNA level by RT-PCR and cDNA sequencing.

RESULTS

A heterozygous single-base substitution (417C-->T) in exon 4 of the beta-IG-h3 gene was detected predicting the replacement of arginine-124 by cysteine. Analysis of 10 family members showed perfect cosegregation of the mutation and lattice corneal dystrophy type I. The investigation excluded this mutation in one family member previously classified as potentially affected.

CONCLUSIONS

The investigation confirmed autosomal dominant inheritance with complete penetrance in the family described. The mutation 417C-->T has already been found earlier in another family of different geographic origin. These results suggest a mutation hot spot at position 417. In addition, no evidence of genetic heterogeneity of lattice corneal dystrophy type I was detected. Molecular genetic analysis (in conjunction with genetic counselling) therefore may be useful in routine diagnostics as the confirmation of the diagnosis by histological examination is possible only after keratoplasty. The common pathomechanism in lattice corneal dystrophy type I may facilitate development of new therapeutic concepts; the easy accessibility of the target organ may provide new possibilities e.g. for gene therapy.

Rapid categorization of natural images by rhesus monkeys

Two rhesus macaques were tested on a categorization task in which they had to classify previously unseen photographs flashed for only 80 ms. One monkey was trained to respond to the presence of an animal, the second to the presence of food. Although the monkeys were not quite as accurate as humans tested on the same material, they nevertheless performed this very challenging visual task remarkably well. Furthermore, their reaction times were considerably shorter than even the fastest human subject. Such data, combined with the detailed knowledge of the monkey's visual system, provide a severe challenge to current theories of visual processing. They also argue that this form of rapid visual categorization is fundamentally similar in both monkeys and humans.

Trafficking of wheat gluten proteins in transgenic tobacco plants: gamma-gliadin does not contain an endoplasmic reticulum-retention signal

Wild-type and mutated forms of the wheat (Triticum aestivum L.) storage protein gamma-gliadin were expressed in transgenic tobacco (Nicotiana tabacum L. cv. NVS) under the control of the 35S cauliflower mosaic virus (CaMV) promoter in order to determine what, if any, endogenous targeting signals are present in the wild-type gamma-gliadin protein. The mutant forms of the protein were modified by the addition of a KDEL or HDEL C-terminal endoplasmic reticulum-retention signal, or the addition of a C-terminal propeptide from barley lectin which has been shown to be necessary and sufficient for targeting to the vacuole. Only modified forms of the protein accumulated in leaves of transgenic tobacco, although the transcript levels were similar for all the constructs. Pulse-chase analysis indicated that whereas the wild-type gamma-gliadin was rapidly turned over in tobacco leaves, KDEL and HDEL forms were highly stable. The vacuolar-signal mutant protein accumulated in tobacco leaves, but migrated on sodium dodecyl sulphate-polyacrylamide gel electrophoresis with a lower mobility than wild-type gamma-gliadin, due in part to glycosylation of the C-terminal propeptide. The vacuolar-signal mutant protein was turned over slowly in tobacco, perhaps indicating a poor level of transport competence. When pulse-chase analysis was carried out on protoplasts isolated from tobacco plants expressing wild-type gamma-gliadin, but in the presence of Brefeldin A, gamma-gliadin was seen to accumulate. Taken together, these results indicate that gamma-gliadin is targeted to the vacuole in transgenic tobacco plants and does not contain any structural determinants which confer retention in the endoplasmic reticulum.

[Measuring intraocular pressure in keratoconus. Effect of the changed biomechanics]

BACKGROUND

Keratoconus is associated with changes in the corneal structure, such as defects of Bowman's layer, a decrease of corneal thickness etc. They result in alterations of some of the biomechanical parameters of the cornea, namely, rigidity and elasticity. The present study was performed to examine how impression tonometry and applanation tonometry for determination of intraocular pressure (IOP) are affected by the changed biomechanical parameters associated with keratoconus.

PATIENTS AND METHODS

We examined 20 normal subjects (40 eyes) and 17 keratoconus patients (25 eyes). The corneal thickness was measured by ultrasound pachymetry in the corneal center. In the keratoconus patients, an additional measurement was made at the conus peak. The corneal curvature was determined using the TMS keratoscope. The IOP measurements were made with the Schiötz tonometer (10 g). For comparison, additional IOP measurements in the corneal center and, in the keratoconus group, on the conus peak were made with the applanation tonometer.

RESULTS

The normal subjects had a central corneal thickness of 548 +/- 30 microns, compared to 505 +/- 42 microns in the corneal center and 425 +/- 41 microns on the conus peak in keratoconus patients. The average corneal curvature was 43.3 +/- 1.8 D in the normal subjects and 47.8 +/- 4.1 D in keratoconus patients. Applanation tonometry produced results on 11.33 +/- 1.43 mm Hg in the normal group (corneal center) compared to values of 12.00 +/- 2.55 mm Hg (corneal center) and 7.30 +/- 1.95 mm Hg (conus peak) in the keratoconus cohort. The coefficient of rigidity was 0.0236 +/- 0.0026 microliter-1 in the normal subjects, compared to 0.0173 +/- 0.0050 microliter-1 in the keratoconus patients.

CONCLUSION

The morphological changes associated with keratoconus may cause tonometry errors.

Linkage studies in erythrokeratodermias: fine mapping, genetic heterogeneity and analysis of candidate genes

Erythrokeratodermias are a clinically heterogeneous group of rare autosomal dominant disorders of cornification with overlapping features including hyperkeratosis and erythema. We ascertained five extended pedigrees with different phenotypes for a linkage study. Three families presented with localized erythrokeratodermia variabilis, and one with erythrokeratodermia and ataxia. Another family had Greither disease associated with variable hyperkeratotic plaques. Despite their phenotypic differences, both erythrokeratodermia variabilis and erythrokeratodermia with ataxia map to a common region in 1p34-p35. Multipoint linkage and haplotype analyses place erythrokeratodermia variabilis between the marker D1S496 and D1S186 with a maximum LOD score of 12.88. Our linkage results provide compelling evidence for genetic homogeneity among families of mixed European and French-Canadian origin. In contrast, results excluded Greither's disease from the established erythrokeratodermia variabilis gene region indicating genetic heterogeneity of erythrokeratodermias. Based on recombinations, two genes assigned to 1p34-p35 were excluded: cartilage matrix protein and avian myelocytosis viral oncogene. Connexin-37 (GJA4), a member of the connexin gene family, maps within the erythrokeratodermia variabilis region and is an attractive candidate gene. Direct sequencing of the coding region of GJA4 in four patients revealed several variations, including a novel polymorphism within the 5' cytoplasmic domain, but no pathogenic mutations were found, thus excluding Connexin-37 as a candidate. There is evidence, however, that other epidermally expressed connexins cluster in this region, and one may yet be determined to play a role in the pathogenesis of erythrokeratodermia variabilis.

Molecular genetic analysis of two families with keratosis follicularis spinulosa decalvans: refinement of gene localization and evidence for genetic heterogeneity

X-linked keratosis follicularis spinulosa decalvans (KFSD) is a rare disorder affecting both skin and eyes. In the two extended KFSD families analysed to date, the gene was mapped to Xp22.13-p22.2. By analyzing several new markers in this region, we were able to narrow the candidate region to a 1-Mb interval between DXS7161 and (DXS7593, DXS7105) in the large Dutch pedigree. In addition, we analyzed 23 markers in Xp21.2-p22.2 in a German family with KFSD. Haplotype and recombination analysis positioned the KFSD gene in this family most likely outside the candidate region on Xp22.13-p22.2. This finding is suggestive for genetic heterogeneity: in this pedigree there is either another locus on the X-chromosome, or KFSD is transmitted here as an autosomal dominant trait with variable expression.

[Development of corneal sensitivity after phacoemulsification with scleral tunnel incision]

BACKGROUND

after anterior segment surgery the anatomical structures and in particular corneal metabolism and corneal trophic are reduced. The corneal wound healing might be monitored by measuring corneal sensitivity.

MATERIAL AND METHOD

In a prospective study of 1 year corneal sensation of 26 patients, age = 72.49 +/- 11.09 years, after phacoemulsification with scleral tunnel is examined. Corneal sensitivity is measured with the Draeger aesthesiometer in the corneal center, in the 6 o'clock and 12 o'clock position before and 4 weeks, 4 months and 1 year after the operation.

RESULTS

The preoperative corneal sensitivity thresholds before the operation are with 11.61 +/- 10.49 x 10(-5) N in the 12 o'clock position, in the center with 2.43 +/- 2.57 x 10(-5) N and in the 6 o'clock position with 11.86 +/0 10.37 x 10(-5) N normal. Even 1 year after surgery corneal sensitivity is markedly reduced with 257.08 +/- 306.71 x 10(-5) N, 107.77 +/- 246.76 x 10(-5) N and 82.81 +/- 140.77 x 10(-5) N in the 6 o'clock position.

CONCLUSION

Even 1 year after phacoemulsification corneal sensitivity is definitely hyposensitive in the center and descretely hypotensitive in the periphery at the 6 o'clock.

[Effect of various ablation levels on endothelial density in the enucleated pig eye. Experimental study with the 193 nm Excimer laser]

The effects of deep excimer laser ablations on the corneal endothelial cell count are still unknown.

MATERIALS AND METHODS

In an in-vitro study the endothelial cell counts of 125 pig corneas were examined after excimer laser ablation. Five groups of 25 eyes reach, one control group and four groups with 3, 10, 20, and 35 D of ablation were examined. After the laser treatment, a corneoscleral disc was prepared and stored for up 5 days in an organ culture medium. The endothelial cell density of 5 corneas in each group was measured in a period of 5 days with a phase contrast microscope.

RESULTS

Significant cell loss, 13-25%, was measured in each group after 5 days. There were no significant differences between the ablated corneas and the control group.

CONCLUSION

Deep excimer laser ablations do not significantly reduce the endothelial cell count.

[Changes in corneal thickness and endothelial cell density after cataract extraction using phacoemulsification]

Corneal metabolism is reduced after cataract extraction.

PATIENTS AND METHODS

In a prospective study the corneal thickness and endothelial cell count of 48 patients were examined after phacoemulsification. Corneal thickness was measured with an ultrasound pachymeter and the endothelial cell count with a contact endothelial camera at the 12 o'clock position and in the corneal center before and 4 weeks, 4 months and 1 year after operation.

RESULTS

One year after the operation, corneal thickness increased about 9% in the 12 o'clock position and about 12% in the corneal center. The endothelial cell count decreased about 27% in the 12 o'clock position and about 18% in the corneal center. We measured a significant correlation between cell loss and age at both points. Concerning the corneal thickness, no significant correlation was found.

CONCLUSION

After cataract extraction corneal metabolism is reduced. The endothelial cell count or corneal thickness can be used as an indicator of the corneal trauma resulting from the operation.

[Change in corneal sensitivity after topical dorzolamide administration. A comparative study]

BACKGROUND

The new antiglaucoma drug, dorzolamide, mainly evokes local side effects like eye burning, pruritus, blurred sight and a foreign-body sensation. A clinical study was conducted to determine it dorzolamide has any influence on corneal sensitivity.

SUBJECTS AND METHODS

We examined three different groups of substances. We used sodium chloride solution 0.9% and the local anesthetic oxybuprocaine 0.4% as control groups, each in two subgroups aged 23-40 years or 60-86 years. Corneal sensitivity was measured in the corneal center with Draeger's electronic optic aesthesiometer. We took the measurements directly before and 1,5,10,15 and 20 min after applying one eye drop.

RESULTS

The control groups with sodium chloride solution showed no significant (P > 0.05) corneal hyposensitivity. The local anesthetic caused corneal asensitivity (P < 0.05) until the 10-min measurement. Twenty minutes after giving the anesthetic, with 12.10(-5) N corneal sensitivity nearly reached the starting value. At this time corneal sensitivity in the older subgroup was still decreased with 627.10(-5) N. In the younger subgroup dorzolamide only caused slight, but significant (P < 0.05), hyposensitivity of the cornea 1 and 5 min after application of the eye drop.

CONCLUSION

Although dorzolamide decreases corneal sensitivity only a little, people with glaucoma using contact lenses should not insert them until at least 15 min after applying the dorzolamide.

Killing kinetics of RP 59500 and pristinamycin against penicillin-resistant pneumococci

The killing kinetics of two streptogramins, RP 59500 and pristinamycin against seventeen isolates of penicillin-susceptible and resistant pneumococci were studied. The antibiotics were tested at 1x, 2x and 4x the MIC for each individual isolate. The results showed a very good and rapid bactericidal activity within 1 hour for concentrations equal or greater to the MIC. These antibiotics are very promising agents for the treatment of infections due to multiresistant pneumococci.

[Alpha/beta and gamma/delta T-cell receptors--analysis of conjunctival tissue of patients with ocular pemphigoid]

BACKGROUND

In the conjunctiva of asymptomatic persons and patients with ocular cicatricial pemphigoid the existence and distribution of alpha/beta- and gamma/delta-T cell receptor (TCR)-positive cells has not previously been investigated.

PATIENTS AND METHODS

Biopsy specimens from 20 patients with clinically diagnosed ocular cicatricial pemphigoid (OCP) were compared with 20 specimens from asymptomatic persons. Additionally, 3 specimens from patients with OCP treated with cytotoxic drugs and 8 specimens from patients who had undergone mucosal transplantation were studied. Antigen retrieval was done in deparaffinized specimens for immunohistochemical identification of alpha/beta- and gamma/delta-TCR-positive cells by monoclonal antibodies and an appropriate detection system. All steps were performed in triplicate, and negative control sera were applied.

RESULTS

alpha/beta-TCR-positive cells were observed in the conjunctival epithelium and stroma of all the asymptomatic persons and in all patients with OCP. gamma/delta-TCR-positive cells were found in 4 out of 20 patients with OCP in epithelial sites, but not in asymptomatic persons. Patients with OCP who had received cytotoxic treatment exhibited neither alpha/beta- nor gamma/delta-TCR-positive cells. Staining sites of alpha/beta-TCR-positive cells changed from membrane-bound to nuclear in patients who had undergone mucosal transplantation, and were cytoplasmic rather than membrane-bound in gamma/delta-TCR positive cells.

CONCLUSIONS

This study presents preliminary evidence for the existence of distinct T-cell subsets in the conjunctiva of healthy persons and of patients with OCP. Further functional studies in fresh tissue material may provide better insights into the role of defined T-cell subsets in the immunopathogenesis of autoimmune diseases of the outer eye such as OCP.

[Endothelial cell loss after phacoemulsification with the "reversed tip and snip" technique compared with the "divide and conquer" technique]

BACKGROUND

The endothelial cell count after phakoemulsification is a sensitive parameter to compare different phakoemulsification techniques.

PATIENTS AND METHOD

In a prospective study 30 patients in each group were operated upon the "Reversed Tip and Snip" and with the "Divide and Conquer"-Technique. The corneal endothelial cell count was measured before surgery and 4 weeks and 3 months after the operation.

RESULTS

The endothelial cell count was reduced significantly about 10% after the the "Reversed Tip and Snip" and about 15% after the "Divide and Conquer"-Technique. The first mentioned technique had a significantly reduced cell loss than the latter.

CONCLUSION

The "Reversed Tip and Snip" phakoemulsification technique causes less endothelial cell loss than the "Divide and Conquer"-Technique.

Killing kinetics of meropenem against penicillin-resistant pneumococci

The killing kinetics of meropenem against sixteen clinical isolates of pneumococci (12 penicillin-resistant, three penicillin-intermediate and one penicillin-sensitive) were studied. Meropenem was tested at 1x, 2x and 4x the MIC for each individual isolate. The results showed a good bactericidal activity with rapid killing of pneumococci (killing > 3 log10 cfu/mL was obtained for nine strains). This strategy needs clinical assessment and might prove to be a suitable alternative to penicillin and cephalosporins for the treatment of mixed infections involving multiresistant pneumococci.

[Rhegmatogenous retinal detachment in atrophia gyrata: pars plana vitrectomy with silicone oil instillation]

BACKGROUND

Gyrate atrophy is a form of choroidal dystrophia characterized by a genetic defect of the mitochondrial matrix enzyme ornithine ketoacidoaminotransferase on chromosome 10. Apart from rare myopathic problems, cases of choroidal, iridal atrophy, complicated subcapsular cataract, optic atrophy, macular edema, reticular retinoschisis, vasculitis and perivasculitis could be observed so far. To our knowledge, rheumatogenous retinal detachment has been described before. We present a 34-year-old female subject with a retinal detachment of the right eye over 3 quadrants with 3 small round foramina in the area 10 to 11 o'clock.

PATIENTS

Concentric defects of the visual field had been known since the age of 4; the patient was slightly myopic. At the age of 31, the patient had undergone cataract extraction with implantation of posterior chamber lenses in both eyes. The ophthalmological examination revealed large areas of choroidal atrophia in both eyes. A determination of visual acuity resulted in hand movements in the right eye and 0.1 in the left eye. The ERG was extinguished.

RESULTS

The retina could be fully reattached by pars plana vitrectomy and instillation of silicone oil. At the same time, we performed an excision of secondary cataract. On demission, the visual acuity of the right eye was finger counting. Because a brother of the patient had also suffering from a progressive choroidal atrophy since his childhood, an autosomal recessive disease was suspected. The only abnormality detected was strongly elevated plasma levels of ornithin (7.5 to 14 mg/dl, compared to levels of 0.6 to 2.0 in controls). Urinary excretion of ornithin was also strongly increased.

DISCUSSION

To our knowledge there was no previous description of a case of atrophia gyrata in association with rhegmatogenous retinal detachment after intraocular surgery. As the pigment epithelium is missing, intraoperative endolaser-coagulation would be useless. For this reason, and since a tendency for reattachment is lacking consistent with one of the characteristics of this disease, the only approach to this case is intraocular tamponade with silicone oil.

Evidence for genetic heterogeneity in monilethrix

Monilethrix is a rare inherited defect of the hair shaft resulting in hair fragility and dystrophic alopecia. In contrast to recent reports mapping monilethrix to the type II epithelial and trichocyte keratin gene cluster on 12q13, we strongly excluded these candidate genes in another family with autosomal dominant monilethrix. Moreover, there was no evidence for linkage of the disease to the keratin gene cluster on chromosome 17q12-q21, thus excluding defects in all known trichocyte and epithelial keratins as the cause of monilethrix in this family. Likewise, several other genes known to play an important role in hair shaft formation (trichohyalin and involucrin, ultra-high sulfur matrix proteins, and transglutaminases 1, 2, and 3) did not provide any evidence for linkage. Our results indicate genetic heterogeneity in monilethrix and suggest that aberrations in at least one other gene result in a similar phenotype.

Treatment of respiratory failure using minitracheotomy and intratracheal oxygenation in selected patients with chronic lung disease

OBJECTIVE

To evaluate the efficacy of minitracheotomy (MT) insertion for intratracheal oxygen insufflation (ITO2) on arterial blood gases and survival in patients with respiratory failure from chronic lung disease.

DESIGN

Open, prospective clinical study.

SETTING

A 12-bed medical intensive care unit in a non-university hospital.

PATIENTS

20 patients (14 males and 6 females, mean age 74.8 +/- 2.6 years), admitted for respiratory failure and denied mechanical ventilation.

INTERVENTION

Percutaneous insertion of an MT for ITO2. Arterial blood gases were drawn just prior to, then 3, 24, 48 h and 1 week after MT insertion. Data are evaluated with a two-way analysis of variance for distribution-free data (Friedman's rank sums test).

MEASUREMENTS AND RESULTS

Three hours after starting ITO2, the partial pressure of oxygen in arterial blood (PaO2) and the arterial oxygen saturation (SaO2) both increased from 51.7 +/- 2.8 to 85.4 +/- 5.6 mmHg and from 79.7 +/- 3.1 to 93.7 +/- 0.9%, respectively (p < 0.001 for both), along with a slight worsening in the partial pressure of carbon dioxide in arterial blood (PaCO2), from 59.6 +/- 2.5 to 63.5 +/- 3.0 mmHg (p < 0.05). At 1 week, improvements in PaO2 and SaO2 were maintained in all patients, while PaCO2 decreased in 14 patients (mean decrease 8.3 mmHg) and increased in the remaining patients (mean 12.5 mmHg), when compared to pre-ITO2 values. Seven patients died during follow-up, leading to a success rate of 65%. Eight and 4 patients were discharged home and to a nursing home, respectively, 9 still receiving ITO2 via MT as chronic oxygen therapy.

CONCLUSION

Our results suggest that MT insertion for ITO2 may be a therapeutic option in selected patients with respiratory failure from CLD.

Detection of endotoxin in media from sterile corneal organ cultures

Lipopolysaccharides (LPS) are elements of the cell wall of gram-negative bacteria. They are also called endotoxins and are known to stimulate various inflammatory reactions by interaction with cytokines and macrophages. Additionally, they may have a direct effect on other cells. As contamination of sterile organ-culture media with bacterial substances may influence the donor-tissue prognosis, we investigated a series of culture media drawn from organ culture for the presence of endotoxin. A total of 341 samples of sterile organ-culture media from 3 different cornea banks using either organ culture or the refrigerated-storage technique were tested for endotoxin. The assay was performed using the Limulus amebocyte-lysate test. A level of endotoxin above the background threshold was found in 99/341 (29%) culture media. The incidence of endotoxin ranged from 14% up to 50%, depending on the cornea bank and culture system used. Endotoxin detected in sterile corneal organ cultures probably derives from nonreplicating bacterial postmortem donor-tissue contamination. The presence of endotoxin-positive cultures varied between the eye banks but was not related to a given storage method. As endotoxin may directly influence graft viability or trigger inflammatory host responses, these findings may have significance for the clinical results of corneal grafting.

Differences in proliferation and migration of corneal endothelial cells [correction of epithelial cells] after cell transplantation in vitro

For regular function the human cornea requires an intact endothelial cell layer with a sufficiently high cell density. One approach used to compensate endothelial cell loss is transplantation of cultured corneal endothelial cells. Using a previously described transplantation protocol, we observed topographic differences after transplantation of cultured human corneal endothelial cells to recipient corneas previously denuded of their own endothelium. The results presented in this paper suggest different interactions of the transplanted endothelial cells with the central or the peripheral part of the corneal matrix, respectively. Furthermore, cells isolated from the center of a human cornea differ from those isolated from the periphery in terms of their mitogenic capacity. The significance of these observations for corneal endothelial cell transplantation is discussed.

Rapid Categorisation of Natural Images with Extrafoveal Presentations

Last year, we showed that most of the visual processing for categorising centrally presented images could be done in 150 ms. The human subjects were given a go — no go categorisation task in which they had to release a button when they could identify an animal. All the pictures were natural scenes taken from a vast CD-ROM data bank allowing access to several thousands of stimuli so that each image was only seen once. Targets (animals) included fish, birds, mammals, reptiles, insects in their natural environment; distractors included landscapes, trees, flowers, fruits. They were presented for a very short duration (20 ms) in order to avoid eye movement. In the present study we wanted to evaluate how the performance was affected with extrafoveal stimulations. We used the same task, but the visual stimuli could be presented at random, either centrally where subjects had to maintain fixation or laterally (left or right hemifield). Behavioural data and concomitant evoked potentials were recorded. The subject's performance was extremely good with a mean score of 90% correct and a mean reaction time of 500 ms. Comparison of performance between central and lateral stimulations showed that most subjects could process lateral and central stimuli with the same speed (reaction time distributions were not statistically different), and that, although extrafoveal presentations induced a drop in the percentage of correct responses (mean decrease 5%), it was not significant in all subjects. Moreover, when compared with last year's study the increase of the number of spatial locations where the visual stimulus could appear did not induce a significant behavioural cost, in terms of speed or accuracy of the response. We also looked at a possible hemispheric specialisation with no clear results. The results obtained here show that even with shared spatial attention and extrafoveal vision, the human visual system is remarkably efficient in an identification task.

Alpha/beta- and gamma/delta-T-cell-receptor-positive lymphocytes in healthy and inflamed human conjunctiva

BACKGROUND

The possible existence and distribution patterns of alpha/beta- and gamma/delta-TCR+ cells, which are important constituents of immune surveillance and act via the CD3+ cell complex have not yet been elucidated in the healthy and inflamed conjunctiva.

MATERIALS AND METHODS

Paraffin-embedded conjunctival specimens included 18 from 18 patients with ocular cicatricial pemphigoid (OCP), 20 from 20 healthy controls, 6 from 6 patients with lye burns, and 6 from 2 patients with Stevens-Johnson syndrome; all were worked up by histology and immunohistochemistry.

RESULTS

alpha/beta-TCR+ cells were visualized in the conjunctival epithelium and stroma of healthy persons, OCP, lye burns and Stevens-Johnson syndrome. alpha/ beta-TCR+ cells and a small number of gamma/delta-TCR+ cells were observed in the corneal epithelium and stroma of patients who have failing corneal grafts. After ileal mucosa transplantation to the epibulbar conjunctiva, membrane staining changes to nuclear and cytoplasmic staining. Treatment with systemic cytotoxic drugs abolishes all alpha/beta-TCR+ and gamma/delta-TCR+ cells.

CONCLUSIONS

alpha/beta-TCR+ cells can be found in the non-infected epithelium and stroma of the healthy and inflamed (OCP, lye burns, and Stevens-Johnson syndrome) conjunctiva, as well as in the corneal epithelium and stroma of failing corneal grafts, whereas gamma/delta-TCR+ cells are absent. A small number of gamma/delta-TCR+ cells are present in the corneal stroma and adjacent conjunctival epithelium of patients with chronic corneal graft rejection or after transplantation of gut tissue. Further investigations may establish the role, if any, of these T-cell subsets in immune surveillance of the non-infected outer eye and in corneal graft rejection.

Structural failure of pyrolytic carbon heart valves

Pyrolite carbon has been used for the manufacture of mechanical heart valve prostheses for the past 25 years. In general, pyrolytic carbon mechanical heart valves have provided adequate physiological function and satisfactory structural performance. Although rare in occurrence, incidents of valve failure due to fracture of one or more components have been reported. These reports of failure are reviewed and a few representative examples are examined in detail in order to determine the characteristic failure mechanism. Understanding the underlying factors responsible for causing these failures provides a solid basis for improved design and manufacture of future mechanical heart valve prostheses.

[In vitro study of the bacteriostatic and bactericidal activity of meropenem against strains of Pseudomonas aeruginosa multiresistant to antibiotics]

Meropenem is a new dehydropeptidase stable carbapenem which has an in vitro bacteriostatic activity superior to imipenem against Pseudomonas aeruginosa. Minimal inhibitory concentrations of meropenem (MEM) and imipenem (IPM) were determined on twelve strains: two were genetically characterized reference strains and ten isolated from patients. Killing curves were performed for MEM used at 1,2 and 4 fold the MIC and 32 mg/l; survivors were counted at baseline and after 5 and 24 hours of incubation by spiral plating. Five strains were susceptible to MEM and IPM; five were intermediate and two resistant to MEM; these seven strains were resistant to IPM. A weak bactericidal effect was obtained after 5 h at each concentration. Only one strain achieved a 3 log 10 reduction after 5 h at 2 x MIC. A regrowth of all the strains tested was observed after 24 h.

Influence of vascular endothelial growth factor on bovine corneal endothelial cells in a wound-healing model

In this study we determined the influence of vascular endothelial growth factor (VEGF) on bovine corneal endothelial cell proliferation and wound healing. Proliferation was determined by measurement of DNA replication as well as by counting of the number of cells present after a defined growth period. In a wound-healing model, reproducible cell-free areas were created within monolayers of cultured bovine corneal endothelial cells and the migration of the cells into these areas was analyzed. The DNA replication and cell proliferation of bovine corneal endothelial cells were not influenced by VEGF. In contrast, in the wound-healing model, VEGF supplementation at concentrations of 1 and 10 ng/ml increased the cell density of the wounded area by 20% and 50%, respectively, as compared with the cell density of wounds left untreated by VEGF. Furthermore, no increase in DNA replication was found in cells involved in wound healing. Our results demonstrate that healing of bovine corneal endothelial cell layers after wounding is predominantly performed by cell migration rather than by proliferation. This migration can be stimulated by the addition of exogenous VEGF.

Correlation of prenatal renal pelvic anteroposterior diameter with outcome in infancy

PURPOSE

We attempted to correlate prenatal renal pelvic anteroposterior diameter with outcome in infancy.

MATERIAL AND METHODS

Between May 1992 and March 1994 we identified 27 cases of fetal hydronephrosis in which renal pelvic anteroposterior diameter was 4 mm. or greater before 33 weeks of gestation and 7 mm. or greater at or after 33 weeks of gestation.

RESULTS

Hydronephrosis was bilateral in 18 fetuses and unilateral in 9. Shortly after birth radiological assessment revealed vesicoureteral reflux in 6 neonates, ureteropelvic junction obstruction in 6, extrarenal pelves in 3 and persistent nonobstructive hydronephrosis in 4. Radiological evaluation was normal in 8 newborns.

CONCLUSIONS

When these screening criteria for hydronephrosis are met prenatally a complete radiological assessment should be done following birth.

[Descemetocele after Excimer laser phototherapeutic keratectomy in herpes simplex virus-induced keratitis: a clinico-pathologic correlation]

BACKGROUND

The indications for phototherapeutic keratectomy in superficial and deep corneal scars in Herpes simplex virus infections are controversial. Serious incidents after PTK have as yet not been reported.

PATIENTS AND METHODS

A 62-year-old patient had suffered from recurrent central herpetic keratitis since 1948 and was treated for corneal scarring for the first time in 1992 by PTK. In 1995, epithelial defects were noted and, since medical treatment was unsuccessful, repeat PTK was performed. Two weeks after the second PTK, stromal infiltration with a subsequent corneal ulcer was followed by a descemetocele and perforation.

RESULTS

The recurrence of Herpes simplex keratitis was treated with systemic acyclovir, and the corneal perforation, the posterior synechiae and the complicated cataract were managed by a triple procedure à chaud (7.0 x 7.5 mm). The inflammation calmed down, and a significant improvement of vision was noted at dismissal. Histopathology of the corneal button showed no epithelial cells, endothelial cell rarefication, loss of Bowman's layer resulting from PTK, stromal edema, a descemetocele with perforation of 1.5 mm in diameter, and immunohistochemically Herpes simplex virus in the deep stroma and pre-Descemet.

CONCLUSIONS

Considering the clinical data and the histopathology we conclude that repeat excimer laser phototherapeutic keratectomy of herpetic keratitis without antiviral coverage may result in complications.

Bactericidal effect of sparfloxacin alone and in combination with amoxicillin against Streptococcus pneumoniae as determined by kill-kinetic studies

Ten clinical isolates of Streptococcus pneumoniae (six intermediately penicillin-sensitive, one penicillin-resistant and three penicillin-sensitive strains) were studied by kill-kinetic experiments using sparfloxacin alone and in combination with amoxicillin. Equipotent doses of the antibiotics (1x, 2x and 4x the MIC) were used in the kill-kinetic studies. Sparfloxacin had a moderate bactericidal potential at 4x MIC after 5h and the combination with amoxicillin did not significantly increase its bactericidal activity. The clinical significance of these findings warrants further studies in vivo.