Influence of cyclodextrins on the in vitro corneal permeability and in vivo ocular distribution of thalidomide

The aim of the present study has been to develop aqueous Thalidomide (THA) eye drops in order to minimize systemic side effects and to improve bioavailability following topical application. Cyclodextrins (CDs), suitable vehicles to improve aqueous solubility of THA, were evaluated with regard to their ability to influence in vitro corneal permeability of THA. Additionally, rabbit eyes received either THA-suspension (0.04%) (THA-SP) or THA (0.04%)/hydroxypropyl-beta-cyclodextrin (HP-beta-CD) (12.5%) solution (THA-CD). In vitro corneal permeation studies demonstrated that the absolute amount of THA permeated could not be increased by means of CDs. The percentile release of THA was extensively decreased using saturated THA/CD solutions. Following loading doses of either THA-CD or THA-SP onto the rabbit eye, significantly increased aqueous humor levels were obtained for THA-CD 30 min (THA-CD:THA-SP=4.6:1) and 60 min (THA-CD:THA-SP=3.1:1) post instillation (p<0.05). In the iris-ciliary body, significantly increased THA levels were obtained using THA suspension (THA-CD(60 min):THA-SP(60 min)=1:6.1) (p<0.05). In the cornea, conjunctiva, vitreous and sclera, differences between the THA tissue levels were not statistically significant. Cyclodextrins might be a useful tool to formulate aqueous THA eye drop solutions and modify intraocular drug bioavailability.

Clinical and electrophysiologic results after intracameral lidocaine 1% anesthesia: a prospective randomized study

OBJECTIVE

To evaluate the efficacy and safety of intracameral lidocaine in cataract surgery compared to peribulbar anesthesia.

DESIGN

A prospective, randomized, controlled study.

PARTICIPANTS

A total of 200 consecutive cataract patients (200 eyes) participated.

INTERVENTION

Eyes were randomly assigned to two groups: one group received 0.15 ml intracameral 1% unpreserved lidocaine combined with topical anesthesia (oxybuprocaine); the other group received 6 ml prilocaine peribulbar before phacoemulsification with sclerocorneal tunnel incision.

MAIN OUTCOME MEASURES

Duration of surgery was measured; implicit time and amplitudes of the b-waves of the photopic electroretinogram (ERG) potentials (single-flash ERG and the 30-Hz flicker ERG) were recorded; frequencies of intraoperative problems, complications, intraoperative, and postoperative pain were evaluated.

RESULTS

After lidocaine anesthesia combined with topical anesthesia, similar complications were found, longer operation time (P < 0.001), and significantly better visual acuity immediately after surgery (P < 0.001). The ERG amplitudes were not significantly reduced after 0.15-ml intracameral lidocaine half an hour after surgery (P > 0.05).

CONCLUSION

Intracameral lidocaine 1% combined with topical anesthesia can be recommended as an alternative procedure to peribulbar anesthesia in cataract surgery with corneoscleral tunnel incision.

Delayed mustard gas keratopathy: clinical findings and confocal microscopy

PURPOSE

To describe the clinical manifestations and confocal microscopic findings in a patient with delayed mustard gas keratopathy.

METHOD

Case report. A 32-year-old veteran who had participated in the Iran Iraq conflict was exposed to mustard gas in 1988. Ocular abnormalities in 1996 and 1998 and corneal confocal microscopic findings in 1998 are presented.

RESULTS

In 1996, slit-lamp examination disclosed bilateral limbal changes with tortuous blood vessels and full-thickness corneal alterations. In 1998, the right eye had porcelain-white episcleral changes and adjacent peripheral ulcerative keratopathy. Confocal microscopy demonstrated irregular-appearing epithelial and basal epithelial cells. The anterior stroma was remarkable for spindle-like keratocytes, diffuse fibrillar inhomogeneities and the presence of highly reflective material.

CONCLUSIONS

Mustard gas keratopathy is a uncommon cause of ocular damage, but it may lead to delayed ocular damage.

The proteasome

Proteasomes are large multisubunit proteases that are found in the cytosol, both free and attached to the endoplasmic reticulum, and in the nucleus of eukaryotic cells. Their ubiquitous presence and high abundance in these compartments reflects their central role in cellular protein turnover. Proteasomes recognize, unfold, and digest protein substrates that have been marked for degradation by the attachment of a ubiquitin moiety. Individual subcomplexes of the complete 26S proteasome are involved in these different tasks: The ATP-dependent 19S caps are believed to unfold substrates and feed them to the actual protease, the 20S proteasome. This core particle appears to be more ancient than the ubiquitin system. Both prokaryotic and archaebacterial ancestors have been identified. Crystal structures are now available for the E. coli proteasome homologue and the T. acidophilum and S. cerevisiae 20S proteasomes. All three enzymes are cylindrical particles that have their active sites on the inner walls of a large central cavity. They share the fold and a novel catalytic mechanism with an N-terminal nucleophilic threonine, which places them in the family of Ntn (N terminal nucleophile) hydrolases. Evolution has added complexity to the comparatively simple prokaryotic prototype. This minimal proteasome is a homododecamer made from two hexameric rings stacked head to head. Its heptameric version is the catalytic core of archaebacterial proteasomes, where it is sandwiched between two inactive antichambers that are made up from a different subunit. In eukaryotes, both subunits have diverged into seven different subunits each, which are present in the particle in unique locations such that a complex dimer is formed that has six active sites with three major specificities that can be attributed to individual subunits. Genetic, biochemical, and high-resolution electron microscopy data, but no crystal structures, are available for the 19S caps. A first step toward a mechanistic understanding of proteasome activation and regulation has been made with the elucidation of the X-ray structure of the alternative, mammalian proteasome activator PA28.

Transcription of 'inactive' expression sites in African trypanosomes leads to expression of multiple transferrin receptor RNAs in bloodstream forms

African trypanosomes express a heterodimeric transferrin receptor that mediates iron uptake from the host bloodstream. The genes encoding the receptor, ESAG6 and ESAG7, are found at the beginning of VSG expression sites: these are telomeric, polycistronic transcription units that each terminate with a gene encoding a trypanosome variant surface glycoprotein, VSG. Approximately 20 of these VSG expression sites are found in the trypanosome genome, but only one VSG is expressed at a time. The conventional view is that one expression site promoter is extremely active whereas the others are either inactive or show very low, poorly processive activity, and that all transferrin receptor molecules are encoded by the active expression site. The 3'-end of the ESAG6 gene is more than 5 kb from the promoter. We show here that 20% of ESAG6 mRNA originates from the 'inactive' expression sites. We suggest that many expression site promoters in trypanosomes show low-level activity throughout the life cycle, and that transcription proceeds for at least 5 kb. This suggests a simplified model of VSG expression site control, whereby the only regulated event is the strong activation of a single expression site promoter in bloodstream forms.

[Modulation of immune mediated diseases of the eye]

The eye is the target of a variety of immune mediated diseases. Advances in the field of immunology have permitted a better understanding of these challenges. This progress has been accompanied by the development of more specific immunomodulating agents. Corticosteroids are still a major agent in the management of ocular immunomediated diseases, but are now supplemented by other potent immunomodulating agents. The excitement in pharmacological research has in turn provided more insight in immune mechanisms and some of the newer agents have been used as "probes" for a better understanding of basic mechanisms. In order to better evaluate the indications of certain agents, the properties of established and forthcoming agents are presented. The field of immunopharmacology includes a multitude of preclinical areas related to the development of immunotherapy and immunotoxicology. This review attempts to address some topics of the current knowledge of the use of immunomodulating agents in ophthalmology.

High-resolution conjunctival contrast-enhanced MRI dacryocystography

We assessed high-resolution MRI of the lacrimal system with conjunctival contrast enhancement in patients with suspected stenosis. We studied 18 patients with epiphora affecting 22 eyes, using a surface coil, before and after conjunctival and intravenous Gd-DTPA. Stenosis or obstruction of the ducts was found in 18 of 22 cases: at canalicular level in 3 cases, at the sac in 7 cases, and in the nasolacrimal duct in 8 cases. Periductal pathology following surgery to the maxillary sinus or dacryocystorhinostomy was seen in three cases. In conjunction with the findings on syringing and/or conventional dacryocystography, the narrowing was classified as stenosis or obstruction.

Gender-related effects of indomethacin on cerebrovascular CO2 reactivity

Prostaglandins are believed to play an important role in the regulation of resting cerebral blood flow and in the vasodilatory response to hypercapnia. Recently, we reported an increased CO2 reactivity (CR) in premenopausal women and, in the past, evidence has accumulated that estrogens might increase basal levels of prostaglandin secretion from endothelial cells. Therefore, one may speculate that gender differences in CR are possibly mediated by higher prostaglandin levels in women. Using transcranial Doppler sonography, we assessed CR before and 90 min after a single dose of 100 mg of indomethacin in 22 healthy volunteers (11 men, 11 women). Before intake of indomethacin, women had a significantly higher CR (4.53+/-0.49 vs. 3.61+/-0.74, P<0.01). Ninety minutes after indomethacin administration, CR decreased to 1.53+/-0.93 in women and 1.60+/-0.92 in men, respectively. The change of CR was 3.00+/-1.29 in women vs. 2.01+/-1.06 in men (P=0.07). For the entire study population, the decrease of CR was linearly correlated with the initial value of CR (rs=0.74, P<0.001). This gender-related difference possibly relates to higher prostaglandin levels as mediators of an increased CR in premenopausal women, although the exact features remain to be clarified.

[Surgical suction in cataract extraction. Postoperative follow-up in 219 cases over 16 years of age]

Nd-YAG posterior capsulotomy in treatment of secondary cataract has the main disadvantage of increasing the risk for pseudophakic retinal detachment by destroying the posterior lens capsule. This is of great interest in high myopic eyes with an increased risk for pseudophakic retinal detachment. In 219 cases of secondary cataract in our clinic a surgical posterior capsule polishing has been performed and this group was followed up over 6 years looking for intra- and postoperative complications.

PATIENTS

The examined group included 209 myopic eyes with a bulbus length > 25 mm and 10 eyes with traumatic cataract; 24 eyes of this group had been primarily operated without a lens. The secondary cataract surgery was performed between 1990 and 1995, and the average follow-up period was 42 months. The intra- and postoperative complications were revealed retrospectively by examination of the patients in our clinic or by interviewing the patients' private doctors.

RESULTS

The patients achieved a mean improvement in vision of 4 lines. In 9 cases intraoperative capsule rupture occurred (4%). In 35 of the operated eyes one or more relapses occurred during the follow-up period that made another polishing necessary (16%), and in 5 cases YAG capsulotomy was eventually performed (2%). Pseudophakic retinal detachment occurred in none of the cases.

CONCLUSION

Surgical posterior capsule polishing is a low-risk procedure for treatment of regenerative secondary cataract. It is indicated especially in myopic eyes in order to reduce the risk of pseudophakic retinal detachment by conserving the posterior lens capsule.

[Confocal microscopy in corneal dystrophies]

BACKGROUND

Confocal microscopy represents a methodology that allows in vivo examination of corneal morphology, particularly of the epithelium and stroma.

MATERIAL AND METHODS

Using the confocal microscope "ConfoScan Modell P2" epithelial, stromal and endothelial changes were evaluated in 11 patients with corneal dystrophies. All findings were compared with data from healthy individuals.

RESULTS

Confocal images could be correlated to conventional (slitlamp) biomicroscopic findings in all patients with corneal dystrophies. In addition, confocal microscopy provided more detailed images particularly of epithelial and stromal changes.

CONCLUSION

Our data indicate that confocal microscopy provides information on living tissue that correlates with that obtained with conventional techniques on fixed and sectioned tissue.

[Optic neuropathy after erythema infectiosum]

BACKGROUND

Optic neuropathies can not always easily be classified as neuritis or ischemic disease.

CASE REPORT

A 39 year old woman suffered from unilateral optic neuropathy 9 days after the acute onset of a general disease with erythema and joint swellings. The optic disc swelling and visual fields resembled an anterior ischemic optic neuropathy, however, a marked improvement was achieved by steroid treatment. The general disease proved to be erythema infectiosum.

CONCLUSIONS

Erythema infectiosum as a frequent children's disease causes very rarely central nervous involvement, optic neuropathy has not been reported yet. In cases of atypical optic neuropathies search for an underlying systemic disease is of value.

[Radiotherapy of exudative senile macular degeneration. A prospective controlled study]

Despite the successful therapy of subretinal neovascular membranes by laserphotocoagulation there are many problems to be overcome. In the case of subfoveolar neovascularization, photocoagulation leads to a sudden decrease in visual acuity. Recently radiotherapy is considered as an alternative. Complications and effectivity were evaluated in this prospective and randomized trial. The initial results are presented.

PATIENTS AND METHODS

There are 76 patients (51 women, 25 men, average age 77.7 +/- 8.6 years) included in the prospective randomized study. All of them show subfoveolar neovascular membranes in FLA and a decrease in visual acuity between 0.05 and 0.5. They were randomly assigned to either the radiotherapy or the control group. Radiotherapy was done within 6 days by 6 x 2 Gy (6 MV photons). The follow-up was at 4 weeks, after 3 months, after 6 months and then every 6 months after the end of radiotherapy. On average the follow-up is at 15.1 months.

RESULTS

Concerning age and visual acuity before therapy, the control group and the radiotherapy group were not significantly different. At 4 weeks after radiotherapy, visual acuity was 0.13 +/- 0.46 (LogMAR). After 12 months, visual acuity at a distance was 0.11 +/- 0.30 in the therapy group and 0.09 +/- 0.13 (P = 0.838) in the control group. Patients with a preoperative visual acuity better than 0.2 improved more after radiotherapy. Metamorphopsy improved in 75% of the therapy group. The following complications could be observed: In the control group 3 patients suffered subretinal bleeding, in the radiotherapy group 3 patients, respectively.

CONCLUSIONS

At present, the follow-up is too short to recommend radiotherapy as a standard procedure in the case of subfoveolar neovascularization. The results in patients with a better preoperative visual acuity encourage us to continue this study.

Cerebral blood flow and CO2 reactivity in interictal migraineurs: a transcranial Doppler study

There is still some controversy about alterations in velocity of blood flow and in cerebral vasomotor reactivity of intracranial arteries in migraineurs during the interictal phase. By means of simultaneous bilateral transcranial Doppler ultrasonography we, therefore, assessed intracranial blood flow velocities and cerebrovascular reactivity to carbon dioxide of all three basal brain arteries in 20 migraineurs during the interictal phase and 30 nonheadache-prone control subjects. Mean blood flow velocities were higher in migraineurs than in controls in all three arteries on both sides, with a significant difference (P < 0.05) for the right anterior cerebral artery and middle cerebral artery under basal conditions and for the right posterior cerebral artery during hypercapnia. Similarly, the cerebrovascular reactivity to carbon dioxide was always higher in patients than in controls, with a significant difference for the left anterior and the right middle cerebral arteries (P < 0.05) and the right posterior cerebral artery (P < 0.01). The broad overlap of cerebrovascular blood flow velocities and CO2 reactivities in patients and controls precluded identification of values diagnostic of migraine. Nevertheless, transcranial Doppler ultrasonography offers the opportunity to noninvasively monitor cerebral blood flow parameters and, therefore, represents a valuable tool for vascular research in migraine.

Testing promoter activity in the trypanosome genome: isolation of a metacyclic-type VSG promoter, and unexpected insights into RNA polymerase II transcription

In trypanosomes, most genes are arranged in polycistronic transcription units. Individual mRNAs are generated by 5'-trans splicing and 3' polyadenylation. Remarkably, no regulation of RNA polymerase II transcription has been detected although many RNAs are differentially expressed during kinetoplastid life cycles. Demonstration of specific class II promoters is complicated by the difficulty in distinguishing between genuine promoter activity and stimulation of trans splicing. Using vectors that were designed to allow the detection of low promoter activities in a transcriptionally silent chromosomal context, we isolated a novel trypanosome RNA polymerase I promoter. We were however unable to detect class II promoter activity in any tested DNA fragment. We also integrated genes which were preceded by a T3 promoter into the genome of cells expressing bacteriophage T3 polymerase: surprisingly, transcription was alpha-amanitin sensitive. One possible interpretation of these results is that in trypanosomes, RNA polymerase II initiation is favored by genomic accessibility and double-strand melting.

[High resolution functional magnetic resonance tomography with Gd-DTPA eyedrops in diagnosis of lacrimal apparatus diseases]

Both dacryocystography and dacryoscintigraphy are well established in the evaluation of stenoses of the lacrimal drainage system. They provide limited information about the ductal anatomy itself and about periductal structures. MR imaging was evaluated for its capability to directly visualize the lacrimal drainage system in detail and simultaneously provide functional characterization of dacryostenosis.

SUBJECTS AND METHODS

Twenty-seven lacrimal drainage systems of 23 patients suffering from epiphora were examined in an MR unit before and after conjunctival and intravenous application of Gd-DTPA using a surface coil.

RESULTS

Dacryostenosis was found in 23 of 27 lacrimal systems. Stenoses were localized to the canalicular (n = 3), saccular (n = 8), and ductal (n = 12) level, and were classified as stenosis or occlusion.

CONCLUSION

MR imaging with conjunctival contrast application allows within one examination both detailed morphological and functional assessment of the lacrimal drainage system with depiction of surrounding structures. Limitations arise mainly from demands on technical and patient-related preconditions.

No effect of prophylactic treatment with metoprolol on cerebrovascular CO2 reactivity in migraineurs

The prophylactic effect of metoprolol in the treatment of migraine is well known, but its mode of action is still unclear. In the past, increased CO2 reactivity has been reported as one pathognomic finding in interictal migraineurs. Using transcranial Doppler we assessed CO2 reactivity in 20 migraineurs before and 3 h after the first intake of 50 mg metoprolol, and subsequently twice after 1 and 8 weeks of continuous therapy with 150 mg metoprolol/d. Before initiation of therapy, migraineurs as a group had increased CO2 reactivity (p=0.07) compared to 20 age- and sex-matched volunteers. While treatment with metoprolol has been reported to affect amplitudes of increased contingent negative variation or visual evoked potentials in interictal migraineurs, it had no influence on enhanced CO2 reactivity in the present study. Moreover, the pretreatment value of CO2 reactivity did not correlate with the clinical efficacy of metoprolol after a 2-month treatment period.

Pertussis complications in Germany--3 years of hospital-based surveillance during the introduction of acellular vaccines

Between 1 November 1993 and 31 October 1996, admissions to paediatric departments for Bordetella pertussis complications were reported to a nationwide, hospital-based active surveillance system. The case definition included pertussis complicated by pneumonia, apnoea requiring assisted ventilation, seizures, encephalopathy or a combination of these. Two hundred sixteen cases of pertussis complications were registered. 57.4% of them were in infants, 50.9% of them less than 6 months old. There were five deaths, three previously healthy children died. At the time of hospital admission, 106 cases would have been eligible for at least three doses of pertussis vaccine, only four (3.8%) had received the recommended number of immunisations. From the second quarter of 1995, the reported number of cases declined. The decrease coincides with an improvement of pertussis vaccination coverage between 1992 and 1995 due to an increased use of acellular vaccines. The reduction of complicated pertussis was observed even in age-groups too young for the recommended vaccinations. The observed decrease could be due to the increase in vaccination coverage with interruption of the chain of transmission to the younger age-groups, to a cyclic decrease in pertussis cases, or to a combination of both. Continued surveillance will provide information on the epidemiological trend of hospitalisations for pertussis complications in the first European country to have introduced vaccination with acellular vaccines on a large scale.

Validation of bioanalytical chromatographic methods

A strategy is discussed for the validation of chromatographic methods that are developed to quantify drugs in biological matrices. Both the validation terminology and the hypothesis testing are briefly reviewed. The emphasis is on the design of the experiments required to allow a reliable conclusion about acceptance or rejection of the bioanalytical method. In particular, it is explained how to evaluate the calibration line, devise experiments to estimate precision and bias and how to determine the stability of the analyte between the time of the sample collection and the analysis of the processed sample.

[Rise in intraocular tension in microkeratome sections (LASIK) and with the GTS trephine system for keratoplasty]

Microkeratome systems are being increasingly applied in lamellar corneal surgery (e.g., LASIK). The results of the few studies on intraocular pressure changes during the microkeratome cut vary widely. In this study, we examined the intraocular pressure pattern (IOP) in relation to the initial pressure.

METHODS

We performed lamellar corneal cuts on freshly enucleated porcine bulbs with three different microkeratome systems and different setting for the initial pressure (10, 20 and 30 mm Hg). The bulbs were cannulated, and the IOPs were recorded online with a two-chamber measuring system. In addition, we examined the GTS trephine system applied for corneal transplantation.

RESULTS

It became obvious that there were significant differences between systems (significance level, P = 0.05). With an initial pressure of 10 mm Hg the measured values of the Schwind system are significantly lower than with the Polytech system, and these values are again significantly lower than with the Chiron microkeratome. With 20 mm Hg the Chiron system shows significantly higher values than both other systems. With 30 mm Hg initial pressure, the pressure values with the Schwind system and with the Chiron microkeratome are significantly higher than with the Polytech system. Thus with all microkeratome systems the middle and maximum pressure values rise in correlation with the initial pressure levels. This effect was not seen with the trephine system. With the same initial pressure, the standard deviation of the measured data of different mikrokeratomes was low (range 3.1-9.0 mm Hg).

CONCLUSION

The pressure values shown are higher than the data published by the manufacturers. There is current discussion as to whether these pressure values are dangerous (e.g. bleeding) or not. The pressure values reached intraocularly during the microkeratome cut depend on the system and also on the present initial intraocular pressure values. Only with the same initial pressure can reproducible applanation and cutting conditions be obtained, which guarantee stable quality of the cut.

[Capsulotomy in intumescent cataract with the high frequency diathermy capsulotom]

BACKGROUND

Intumescent or hypermature cataracts sometimes mean a difficult capsulorhexis. High frequency capsulotomy represents a satisfying solution for this problem.

PATIENTS AND METHODS

26 patients with intumescent cataracts undergoing cataract surgery with high frequency capsulotomy were enclosed into this study. Clinical application of this technique was examined intraoperatively and postoperatively.

RESULTS

Only in 4 patients out of 26 it was not possible to achieve a circular cut by capsulotomy. Residual bridges could be cut by scissors.

CONCLUSIONS

High frequency capsulotomy means a convenient alternative to capsulorhexis, while correct technique intraoperatively is extremely important for satisfying clinical results.

Sex dependency of cerebrovascular CO2 reactivity in normal subjects

BACKGROUND AND PURPOSE

Cerebrovascular CO2 reactivity can be assessed easily and reliably by transcranial Doppler sonography. The objectives of the present study were to evaluate sex differences in cerebral CO2 reactivity and to specify the relation between CO2 and cerebral blood flow velocity.

METHODS

CO2 reactivity of the circulation of both middle cerebral arteries was measured by bilateral transcranial Doppler sonography in 60 healthy volunteers (30 men, 30 women) aged 21 to 58 years. End-tidal carbon dioxide tensions (PETCO2) were elevated with the use of carbogene gas (95% O2, 5% CO2). In each subject the mean blood flow velocity (Vmean) was plotted as a function of PETCO2.

RESULTS

The best-fit curves for the relation of Vmean/PETCO2 were exponential functions, with the following basic equation: Vmean (cm/s) = aebx, where a is a theoretical quantity representing Vmean at a PCO2 of 0 mm Hg, b is the relative slope of the curve (slope divided by the value of the function) corresponding to the definition of reactivity, and x is the PETCO2 (mm Hg). The mean value of b was 0.037 +/- 0.008 in women and 0.030 +/- 0.010 in men. ANOVA demonstrated a significant difference between men and women (P < .001).

CONCLUSIONS

This study demonstrates a highly significant sex-related difference in CO2-induced cerebral vasomotor reactivity. The relation between altered carbon dioxide tensions and blood flow velocities of both middle cerebral arteries in 60 healthy volunteers was found to be exponential.

Fibroblast growth factor 2, heparin and suramin reduce epithelial ulcer development in experimental HSV-1 keratitis

BACKGROUND

We have previously shown that basic fibroblast growth factor (FGF-2) enhances corneal epithelial healing in different experimental models in vivo. In order to study the healing effect of this growth factor in pathological conditions of the cornea, we investigated whether topical application of FGF-2 could affect herpes keratitis in rabbits. Since HSV-1 infection is prevented in vitro by incubation with heparin, we also topically applied heparin and suramin, considering the similar interaction of herpes simplex virus and FGF-2 with cell membrane-anchored heparan sulfate.

METHODS

After virus inoculation with a human BEY.2 strain, rabbits were treated with either FGF-2 (200 ng to 2 micrograms/application), heparin (250 micrograms/application) or suramin (250 micrograms/application) 4 times daily until day 14. Acyclovir and placebo administrations served as controls (n = 48 rabbits). Computerized ulcer surface analysis, clinical observations and virus recovery assays were performed.

RESULTS

Topical FGF-2, heparin and suramin treatment revealed a significant reduction in peak ulcer sizes, and complete epithelial healing was achieved earlier than in placebo-treated corneas. However, no significant antiviral effect of FGF-2, heparin and suramin was detectable in plaque assays from conjunctival swabs.

CONCLUSIONS

These experiments demonstrate that FGF-2 is effective in promoting herpetic epithelial ulcer healing, either due to its proliferative effects on epithelial cells or indirectly by occupying the sites on cell surface heparan sulfate necessary for the attachment of the virion. The latter mechanism of action is presumably the reason for the similar effect of heparin and suramin.

Krüppel target gene knockout participates in the proper innervation of a specific set of Drosophila larval muscles

Krüppel (Kr) encodes a zinc finger-type transcription factor expressed in spatially and temporally restricted patterns during Drosophila embryogenesis. Molecular targets and the mechanism of Kr action have been studied extensively during the early segmentation process, but only little is known about Kr requirement during later development. We report the identification of a target gene of Kr, termed knockout (ko), isolated by virtue of Krüppel in vitro binding sites. Loss and gain of function experiments show that Kr activity maintains ko expression in a subset of muscles. ko encodes a novel protein expressed in several embryonic tissues including Kr-expressing muscles. Movements of embryos deficient for ko activity are uncoordinated. Their muscle pattern is normal, but the patterns of neuromuscular innervation are specifically disarranged. The results suggest that the Kr target gene ko is required for proper innervation of specific muscles by RP motoneurons.

Specific muscle identities are regulated by Kruppel during Drosophila embryogenesis

During Drosophila embryogenesis, mesodermal cells are recruited to form a complex pattern of larval muscles. The formation of the pattern is initiated by the segregation of a special class of founder myoblasts. Single founders fuse with neighbouring nonfounder myoblasts to form the precursors of individual muscles. Founders and the muscles that they give rise to have specific patterns of gene expression and it has been suggested that it is the expression of these founder cell genes that determines individual muscle attributes such as size, shape, insertion sites and innervation. We find that the segmentation gene Kruppel is expressed in a subset of founders and muscles, regulates specific patterns of gene expression in these cells and is required for the acquisition of proper muscle identity. We show that gain and loss of Kruppel expression in sibling founder cells is sufficient to switch these cells, and the muscles that they give rise to, between alternative cell fates.

A prospective evaluation of a diffractive versus a refractive designed multifocal intraocular lens

OBJECTIVE

To evaluate prospectively a diffractive (811E, Pharmacia; power add +4.0 D) versus a refractive (PA154N, Allergan; power add +3.5 D) designed multifocal lens.

PARTICIPANTS

Eighty patients planned for cataract surgery without additional ocular pathologies were randomized into the diffractive or refractive group, respectively.

INTERVENTION

A standardized no-stitch phacoemulsification with implantation of one of the two multifocal lenses was performed in each patient.

MAIN OUTCOME MEASURES

Distance and near-visual acuity, contrast sensitivity, low contrast visual acuity, glare visual acuity, and depth of focus were measured after surgery.

RESULTS

All treated patients had best-corrected visual acuities of 20/30 or better. Near-uncorrected vision was significantly better (P < 0.0001) with the diffractive lens (mean, J1) than with the refractive lens (mean, J4). Low contrast visual acuity (61 +/- 12% versus 59 +/- 9%), glare visual acuity (39 +/- 19% versus 38 +/- 14%), and contrast sensitivity (1.48 +/- 0.08 versus 1.50 +/- 0.12) were not significantly different between the groups.

CONCLUSIONS

Both lens designs showed satisfactory functional results with advantages for the diffractive lens design.

Mechanisms of developmental regulation in Trypanosoma brucei: a polypyrimidine tract in the 3'-untranslated region of a surface protein mRNA affects RNA abundance and translation

Salivarian trypanosomes are extracellular parasites of mammals that are transmitted by tsetse flies. The procyclic acidic repetitive proteins (PARPs) are the major surface glycoproteins of the form of Trypanosoma brucei that replicates in the fly. The abundance of PARP mRNA and protein is very strongly regulated, mostly at the post-transcriptional level. The 3'-untranslated regions of two PARP genes are of similar lengths, but are dissimilar in sequence apart from a 16mer stem-loop that stimulates translation and a 26mer polypyrimidine tract. Addition of either of these PARP 3'-untranslated regions immediately downstream of a reporter gene resulted in developmental regulation mimicking that of PARP. We show that the PARP 3'-UTR reduces RNA stability and translation in bloodstream forms and that the 26mer polypyrimidine tract is necessary for both effects.

[Use of of the high frequency capsulotomy instrument in cataract surgery--effect of coagulation on corneal endothelium]

Intumescent or hypermature cataracts make a safe capsulorhexis impossible. High frequency capsulotomy represents a satisfying solution for this problem. Primary goal of the present study was to investigate a possible damage to the corneal endothelium by this method.

MATERIALS AND METHODS

55 patients with an uncomplicated senile cataract were enclosed into a prospective randomized study undergoing cataract surgery with capsulorhexis or with high frequency capsulotomy. Corneal endothelium was examined preoperatively as well as postoperatively at several intervals.

RESULTS

Concerning loss of endothelial cells and parameters of polymegatism and pleomorphism there were no statistically significant differences between both groups.

CONCLUSION

The diathermy during high frequency capsulotomy does not show any clinically relevant negative effects on the corneal endothelium within cataract surgery.

The wheat mitochondrial rps13 gene: RNA editing and co-transcription with the atp6 gene

Northern analyses and reverse transcription-polymerase chain-reaction (RT-PCR) experiments, followed by PCR amplification product sequencing, were performed on total mitochondrial (mt) RNAs from wheat seedlings and tissue cultures. It was shown that the rps13 gene, which encodes ribosomal protein S13, and the atp6 gene, which encodes subunit 6 of the ATP synthase complex, were co-transcribed. However, rps13 transcripts were virtually undetectable in seedlings under conditions where atp6 transcripts appeared abundant. In addition, markedly higher steady state transcript levels were observed in tissue culture. Expression of the mitochondrial rps13 gene was confirmed by showing that its transcripts were edited. Slight differences between editing patterns of tissue-culture and whole-plant transcripts were found. Taken together, these results suggest that in vitro culture could disturb the post-transcriptional regulation of gene expression.

Specular microscopy: from speculative to spectacular microscopy

The evolution of confocal microscopy for in vivo qualitative analysis of the cornea seems to follow a path similar to that followed by specular microscopy after its reintroduction almost 20 years ago. The purpose of this report is to present the evolution of our own research data, starting with speculation concerning the attribution of morphological features and finishing with cell-to-cell correlation with special techniques. We present representative clinical but mainly experimental data from relocation studies using flat preparation, especially developed sequential vital staining techniques, and scanning electron microscopy as compared with specular microscopy. Starting from speculative attribution of the observed morphological features, we were capable of classifying morphological data on the endothelium and the surrounding structures into preendothelial, endothelial, retroendothelial, and non-endothelial features. Specular microscopy allows the detailed study of cellular and even intracellular structures and is probably one of the most spectacular ways of doing noninvasive in vivo microscopy in humans.

[Pathogenesis of complicated cataract in herpetic kerato-uveitis]

BACKGROUND

Keratitis, retinitis and secondary cataract are well known complications of ocular herpes simplex infection. We report on a case of herpetic keratouveitis and cataract. Acute and inflammatory pathogenesis of cataract formation resemble a phacoanaphylactic reaction.

CASE REPORT

A 15-year-old girl with recurrent herpes keratitis was referred for acute spontaneous cataract formation accompanied by iridocyclitis and hypotony. Visual acuity was decreased from 0.4 to light projection. During cataract extraction the anterior chamber was tabbed for immunological analysis. The thickened anterior lens capsule was examined by light microscopy. We found a significant local synthesis of herpes antibodies in the aqueous. Histologically the lens capsule depicted a defect and a granulomatous inflammatory infiltrate towards the basal membrane material. The specimen was not suitable to judge on eventual additional phacoanaphylaxis. After cataract extraction and systemic acyclovir and corticosteroids the keratouveitis subsided. Visual acuity improved to 0.4, but was limited by the disciform corneal scar.

CONCLUSION

The granulomatous response towards lens capsule shown here, resembles the granulomatous reaction towards Descemet's membrane in advanced herpetic corneal ulcer. We speculate on the pathogenesis of the lens capsule defect as a, so far unknown, herpes-associated autoimmun response against the basal membrane material of the lens. The acuteness of cataract formation may be a consequence of contact of aqueous with lens fibres. Additional phacoanaphylaxis combined with secondary glaucoma is possible.

A comparative study of the mitochondrial genome organization in in vitro cultures of diploid, tetraploid, and hexaploid Triticum species

Southern-blot hybridizations of total DNA to mitochondrial DNA (mtDNA) probes were used to investigate the extent of mtDNA variability in cultures derived from immature embryos of diploid (Triticum monococcum, genomic formula: AA, T. tauschii, genomic formula: DD), allotetraploid (T. durum cv "Creso", genomic formula: AABB), and allohexaploid (T. aestivum, genomic formula: AABBDD) wheat species. Similar distinct changes in mtDNA organization were observed in in vitro cultures of the derived tetraploid and the hexaploid species with related genomes. The tetraploid and hexaploid species share the B genome and mtDNA variability in in vitro culture is known to be under nuclear control. These results suggest that a study of B genome diploids and other polyploid combinations would now shed light on whether or not mtDNA variability in tissue cultures is under B-genome control.

[New communication media for ophthalmology]

BACKGROUND

The use of high-tech communication is undoubtedly growing and has become established in almost all sciences and research fields. This article surveys the possibilities for scientific data-exchange via the Internet, the world's largest computer network.

METHODS

An introduction is given to network as a whole, its history and structure, and the hardware and software required. Examples are provided to describe the basic services on the Internet with special emphasis on World wide web applications.

CONCLUSIONS

The paper indicates that the Internet has a vast potential for providing almost unlimited information of relevance to users. By using the Internet and its resources, modern ophthalmological research will become more effective and successful.

Intramolecular recombination of a mitochondrial minicircular plasmid-like DNA of date-palm mediated by a set of short direct-repeat sequences

A molecular clone containing the complete sequence of a mitochondrial circular plasmid-like DNA (the R plasmid) isolated from the date-palm variety V3DP was used as a probe in Southern analyses of mitochondrial DNA prepared from other varieties. Another circular structure (the S plasmid) was detected in some of these varieties, and sequenced from variety V2DP. It appears that the R plasmid could have arisen from the S plasmid by an intermolecular recombination event at a set of 26-bp imperfect short direct repeats.

The PARP promoter of Trypanosoma brucei is developmentally regulated in a chromosomal context

African trypanosomes are extracellular protozoan parasites that are transmitted from one mammalian host to the next by tsetse flies. Bloodstream forms express variant surface glycoprotein (VSG); the tsetse fly (procyclic) forms express instead the procyclic acidic repetitive protein (PARP). PARP mRNA is abundant in procyclic forms and almost undetectable in blood-stream forms. Post-transcriptional mechanisms are mainly responsible for PARP mRNA regulation but results of nuclear run-on experiments suggested that transcription might also be regulated. We measured the activity of genomically-integrated PARP, VSG and rRNA promoters in permanently-transformed blood-stream and procyclic form trypanosomes, using reporter gene constructs that showed no post-transcriptional regulation. When the constructs were integrated in the rRNA non-transcribed spacer, the ribosomal RNA and VSG promoters were not developmentally regulated, but integration at the PARP locus reduced rRNA promoter activity in bloodstream forms. PARP promoter activity was 5-fold down-regulated in bloodstream forms when integrated at either site. Regulation was probably at the level of transcriptional initiation, but elongation through plasmid vector sequences was also reduced.

The immunology of bullous oculo-muco-cutaneous disorders

In skin-blistering diseases, alteration of cellular adhesion results in a loss of cohesion of the epithelium of the skin and the mucous membranes. These disorders are often genetically determined and involve highly specific autoantibodies. A recent workshop discussed the immunology of these diseases.

Neutral endopeptidase: variable expression in human lung, inactivation in lung cancer, and modulation of peptide-induced calcium flux

Neutral endopeptidase (NEP; CALLA, CD10, EC 3.4.24.11) is a cell surface endopeptidase that hydrolyses bioactive peptides, including the bombesin-like peptides, as well as other neuropeptides. Bombesin-like peptides and other neuropeptides are autocrine growth factors for both small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). Low expression of NEP has been reported in SCLC and NSCLC cell lines. NEP inhibition has been shown to increase proliferation in one cell line. To date, NEP expression has not been quantitatively evaluated in normal adult lung, SCLC or NSCLC tumors, paired uninvolved lung from the same patient, or in other pulmonary neoplasms such as mesotheliomas and carcinoids. We examined the expression of NEP in these tissues and human cell lines using immunohistochemistry, flow cytometry, enzyme activity, ELISA, Western blot, and reverse transcription (RT)-PCR. Uninvolved lung tissue from different individuals displayed considerable variation in NEP activity and protein. By immunohistochemistry, NEP expression was detectable in alveolar and airway epithelium, fibroblasts of normal lung, and in mesotheliomas, whereas it was undetectable in most SCLC, adenocarcinoma, squamous cell carcinoma, and carcinoid tumors of the lung. NEP activity and protein levels were lower in all SCLC and adenocarcinoma tumors when compared to adjacent uninvolved lung, often at levels consistent with expression derived from contaminating stroma. NEP expression and activity were reduced or undetectable in most SCLC and lung adenocarcinoma cell lines. NEP mRNA by RT-PCR was not expressed or was in low abundance in the majority of lung cancer cell lines. The majority of lung tumors did not express NEP by RT-PCR as compared with normal adjacent lung. In addition, recombinant NEP abolished, whereas an NEP inhibitor potentiated, the calcium flux generated by neuropeptides in some lung cancer cell lines, demonstrating potential physiological significance for low NEP expression. NEP, therefore, is a signal transduction and possibly a growth modulator for both SCLC and NSCLC, emphasizing the role of neuropeptides in the pathogenesis of the major histological forms of lung cancer.

Structure-activity relationships of a new family of steroidal aromatase inhibitors. 1. Synthesis and evaluation of a series of analogs related to 19-[(methylthio)methyl]androstenedione (RU54115)

During the course of a study aimed at the search for new potent aromatase inhibitors, several new androstenedione analogs were synthesized and evaluated. This study led to the discovery of 19-[(methylthio)methyl]androsta-4,9(11)-diene-3,17-dione (7; RU54115) already described by our laboratory. The object of the present series of papers is to disclose the result of the structure-activity relationship studies that gave rise to this compound. This first part deals mainly with the substitution in the 19-position of the steroid nucleus. Several parameters were varied, the length of the chain and its rigidity and branching, as well as the nature of the heteroatom itself and its substitution. The interaction of these new compounds with human placental aromatase in competition with the substrate androstenedione was studied by difference visible spectroscopy. The in vivo aromatase-inhibiting activities were evaluated by measuring the estradiol lowering after oral administration of the compounds to PMSG-primed female rats.

[Autoimmune diseases of the peripheral cornea. Immunopathology, clinical aspects and therapy]

Noninfectious ulceration of the peripheral cornea remains a major diagnostic and therapeutic challenge. The pathogenesis in most of these disorders is unclear, however, on the basis of systemic connective tissue diseases, autoimmune mechanisms are most likely involved. The peripheral cornea has distinct morphological and immunological characteristics that predispose for inflammatory reactions. Major differences exist regarding humoral and cellular components of the immune system. In the peripheral cornea there is more high-molecular IgM and initial complement component C1 than in the central cornea and may predispose for immune complex formation. The close contact to the conjunctival vasculature provides the basis necessary to generate an immune response. Langerhans cells and macrophages as important antigen presenting and processing cells are present in higher number in the peripheral cornea. Autoimmune diseases that affect the peripheral cornea include collagen vascular diseases and Mooren's ulcer. Although this association is obvious in advanced rheumatoid arthritis more subtle forms of polyarteritis nodosa or systemic lupus erythematosus require careful medical evaluation and workup. Ocular manifestations may present as the initial clinical signs and require careful workup in these potentially lethal disorders.