Effect of folding on the multifocal silicone intraocular lens: scanning electron microscopic study

PURPOSE

To evaluate whether the surface of the refractive zonal multifocal silicone intraocular lens (IOL) is altered by different folding and implantation instruments and is more sensitive to manipulation during folding than the surface of a monofocal IOL.

SETTING

Department of Ophthalmology, University Hospital, Kiel, Germany.

METHODS

Evaluated were the refractive multifocal silicone IOL (SA-40N, Array) and an otherwise identical monofocal IOL (SI-40NB) from the same manufacturer (Allergan Inc.). Different folding devices (folding blocks, folding and implantation forceps, and an injector system) were used. The IOLs were kept folded for 60 seconds; 24 hours later, scanning electron microscopy (SEM) was performed. In addition, the cartridges of the injector system were examined by SEM.

RESULTS

Overall, regardless of the folding and implantation instruments used, both the multifocal and monofocal IOLs had discrete surface alterations. The cartridges of the injector system had a rough surface at the tip, while the proximal portion appeared smooth.

CONCLUSION

There were no signs of lesions particularly affecting the surface of multifocal IOLs.

The "Boston model" of managed care and spinal cord injury: a cross-sectional study of the outcomes of risk-based, prepaid, managed care

OBJECTIVE

To present preliminary data on the health-related consequences for people with spinal cord injury (SCI) of participation in a prepaid, risk-based, managed care plan.

DESIGN

Baseline data from a longitudinal interview survey.

SETTING

Massachusetts.

PARTICIPANTS

Subjects were 114 independently living adults with SCI recruited from 6 independent living centers and 2 managed care plans; 45 received care from a risk-based prepaid managed care plan and 69 from other sources.

MAIN OUTCOMES

Self-reports of use of health services; self-assessments of health, health at interview versus 12 months earlier; hospital admissions; numbers of secondary conditions, and experiences of specific secondary conditions (eg, pressure ulcers, depression, fatigue, and chronic pain).

RESULTS

Persons in the managed care plan do not differ from their counterparts in terms of age, gender, education, level of SCI, number of comorbid conditions, activity of daily living profiles, household composition, and reliance upon health maintenance programs and routines (eg, bowel and bladder care). In terms of processes of care, they appear generally better-served. There also are a few differences in outcome that are statistically significant, or approach significance, and generally favor the managed care plan.

CONCLUSION

Preliminary data suggest that thoughtfully and sensitively designed and implemented risk-based managed care may improve both access and outcomes.

Decrease of antigastric autoantibodies in Helicobacter pylori gastritis after cure of infection

H. pylori infection leads to the formation of autoantibodies against canalicular structures with human parietal cells in about 30% of all patients. This type of autoreactivity is associated with gastric mucosa atrophy. This study aimed to analyse the effect of cure of infection on anticanalicular autoantibodies. H. pylori infection was cured in 34 patients. Sera of these patients were screened for anticanalicular autoantibodies using an immunohistochemical method before, 10 weeks after and one year after cure of infection. Prevalence of anticanalicular autoantibodies significantly decreased from 26% before treatment to 9% after one year. The data presented in this study add new information to the possible reversibility of gastric mucosa atrophy.

Antibodies to factor XII associated with lupus anticoagulant

Falsely low levels of factor XII (FXII) have been documented in patients who are lupus anticoagulant positive (LA+). In addition, we have previously noted a surprisingly high incidence (20.9%) of apparently true FXII deficiency in patients who were LA+. We have hypothesised that this may be partly due to the presence of antibodies to FXII. The aim of the present study was to investigate whether LA+ patient plasmas contain antibodies directed either against FXII or FXII in association with phospholipids. Plasma samples from 60 blood donors, all LA negative, and 51 LA+ patients were tested using ELISA assays employing purified FXII, phosphatidylserine (PS) and phosphatidylethanolamine (PE). We have identified seven patients whose plasma contained either IgG or IgM that reacted with purified FXII in the absence of PS or PE. When PS was included in the assay system four additional patient plasmas were shown to contain either IgG or IgM that reacted with FXII. The plasma of one patient contained IgG that reacted with FXII both in the presence and absence of PS. There was no reactivity to FXII with either IgG or IgM when PE was included in the assay system. Affinity purified IgG from three patients whose plasma reacted with FXII in the ELISA assay in the absence of PS, gave a positive reaction in an immunoblot assay. These results suggest that FXII antibodies are present in a significant proportion of LA+ patients and may lead to an erroneous diagnosis of FXII deficiency.

Quantification of intraocular retained perfluorodecalin after macroscopic complete removal

BACKGROUND

A study was performed to determine the amount of intraocular retained perfluorodecalin after macroscopic complete removal.

MATERIAL AND METHODS

Freshly enucleated pig eyes had the anterior segment removed, vitrectomy was carried out, and the eye cups were placed in 0.9% buffered saline solution. One millilitre of perfluorodecalin was instilled for 30 min, followed by a fluid-air exchange. Perfluorodecalin was macroscopically removed. The retina was rinsed twice with 0.9% buffered saline solution. In a second group no rinsing was done, while in a third group no fluid-air exchange was performed. Finally all eye cups were filled with 2.0 ml of the perfluoropolyether Hostinert 130 to dissolve retained perfluorodecalin. The quantity of perfluorodecalin in perfluoropolyether was determined by gas chromatography.

RESULTS

Retained perfluorodecalin was detected in all experiments. The smallest portion of perfluorodecalin retained (range 0.04-0.08, mean 0.058%, SD +/- 0.015%) was observed without fluid-air exchange. After fluid-air exchange the portion with rinsing was 0.11-0.27% (mean 0.21%, SD +/- 0.059%) and that without rinsing was 0.51-0.69% (mean 0.60%, SD +/- 0.065%).

CONCLUSIONS

Even after macroscopic complete removal of perfluorodecalin a thin layer remains on the retina. If intraoperative fluid-gas exchange is necessary, multiple rinsing with 0.9% buffered saline solution should be performed to reduce the amount of perfluorocarbon liquid retained.

Longitudinal evaluation of growth, puberty, and bone maturation in children with Williams syndrome

OBJECTIVES

To establish syndrome-specific growth curves and growth rate (GR) curves for Williams syndrome (WS) and define the pattern of bone maturation and pubertal development.

METHODS

In a prospective longitudinal study between 1990 and 1997, the growth data of 244 children with WS were collected: 295 values for GR were calculated for 74 girls and 331 values for 89 boys.

RESULTS

Mean GR of children with WS was below normal by 1 to 2 cm/y in the first few years of life. One group of girls (n = 20) experienced an early pubertal growth spurt at age 9 years (maximal GR, 7.8 +/- 2.1 cm/y; menarcheal age, 10.4 +/- 1.4 years). A second group (n = 5) showed the growth spurt at age 11 years (7.5 +/- 1.1 cm/y; menarcheal age, 12.6 +/- 1.3 years). In boys, peak height velocity (8.7 +/- 2.3 cm/y) occurred at age 11 to 12 years. Bone age was delayed in both sexes during childhood and accelerated markedly during puberty. Final height was 152.4 +/- 5.7 cm in girls (n = 38) and 165.2 +/- 10. 9 cm in boys (n = 43).

CONCLUSIONS

The syndrome-specific GR curves for WS showed a premature and abbreviated pubertal growth spurt in both sexes. This growth spurt was directly related to bone age acceleration during puberty. The data from this longitudinal study provide an overview of both the dynamics of growth and its course in children with WS.

[Modified moisture chamber]

BACKGROUND

Moisture chambers can protect the eye in corneal lubrication or eyelid closure disorders. However, in cases with protrusio bulbi or pronounced chemosis conjunctivae direct damaging contact of the cornea or conjunctiva on the one hand and the inside of the moisture-chamber-bandage on the other hand are possible. Since commercial moisture-chamber-bandages are not available with different internal radii, new methods are necessary to increase the distance between the bandage and the eye.

MATERIAL AND METHODS

A special pressure relieving foam dressing used in the therapy and prophylaxis of decubitus was prepared in such a way that a periocular attachment was enabled and an opening for the eye was left blank. This central opening was covered with a commercial moisture-chamber-bandage. Five test persons and two ventilated patients with protrusio bulbi and manifest lagophthalmus were treated with the modified moisture chamber. The relative humidity within the bandage was measured.

RESULTS

The modified moisture chamber allows an individual adaptation to the periocular shape of the face and rises the level of the monoculus for about 7 mm. The internal relative humidity was for eight hours at 98% in both test persons and patients. All test persons felt more comfortable with the modified moisture chamber on their skin.

CONCLUSIONS

The presented modified moisture chamber is a derivative of the commercial monoculus bandage for patients with sensitive protrusio bulbi.

Synthesis of hydantoins via N,N'-ureas derived from polymer-bound amino acids

Starting from carboxy-linked amino acids on trityl functionalized polystyrene resin a highly efficient solid-phase synthesis of hydantoins via N,N'-ureas was elaborated. The polymer-bound hydantoins can be used as a scaffolds for further combinatorial transformations, such as alkylation. Cleavage from the resins yielded the corresponding hydantoins in good yields and purities as shown by ESI-MS and HPLC.

[Depth of lamellar keratoplasty with the guided trephine system for transplantation of full-thickness donor sections]

BACKGROUND

Despite the fact that deep lamellar keratoplasty (DLKP) is less invasive than to penetrating keratoplasty (PKP), this procedure is rarely performed. We therefore investigated whether or not the DLKP technique we employed can achieve stable improvement of visual acuity.

MATERIALS AND METHODS

Thirty-three eyes underwent TLKP for treatment of superficial corneal pathology. The donor tissue transplanted was suitable for PKP. The donor lenticule was obtained on the artificial chamber of the guided trephine system (GTS). The recipient cornea was trephined with the same trephine to a depth of 680 microns. Manual dissection was performed with a bevel-up blade. The donor lenticule with the endothelium peeled off was then sutured in with a 10 x 0 nylon double-running antitorque suture. Cortisone-antibiotic eye drops were administered postoperatively.

RESULTS

Throughout the series no complications occurred. The mean best corrected visual acuity (BSCVA) over glasses was 0.29 (+/- 0.21) preoperatively, 0.1 (+/- 0.11) at 1 week, 0.33 (+/- 0.14) at 1 month, 0.5 (+/- 0.13) at 6 months, 0.61 (+/- 0.16) at 1 year and 0.63 (+/- 0.15) at 2 years. Clinically, we observed two subpopulations. In the first group of 87% of the cases, mean BSCVA was 0.67 (+/- 0.07) at 6 months. The remaining cases (BSCVA < or = 0.25 at 6 months) achieved a mean BSCVA of only 0.2 (+/- 0.04) at 1 year. Mean corneal astigmatism measured 2.93 D (+/- 1.62) preoperatively, 2.69 D (+/- 1.18) at 1 month, 2.09 D (+/- 1.07) at 1 year, and 2.22 D (+/- 1.11) at 2 years. We did not observe any graft rejection.

CONCLUSION

The technique reported for DLKP provides excellent matching of donor lenticule and recipient bed. Separation of donor and recipient stroma prevents interface healing. DLKP appears to be a safe procedure for the surgical treatment of superficial corneal pathology and may offer a clinically applicable alternative to PKP.

Scanning electron microscopic findings on intraocular metallic foreign bodies

BACKGROUND

The study reported here was performed to investigate morphologic intraocular reactions on the surface of metallic intraocular foreign bodies (IOFB) with scanning electron microscopy.

METHODS

Twenty-seven extracted IOFB were investigated. Of these, 22 were situated in the vitreous body; 19 had contact with the retina. Five IOFB had been removed from the anterior segment (control group). The duration of intraocular retention was 6 h to 24 days. Immediately after microsurgical removal the IOFB were fixed, dehydrated, dried, sputter-coated and investigated with a scanning electron microscope. Two IOFB from the vitreous were treated for collagen preservation.

RESULTS

Eighteen of 20 intravitreal IOFB showed fibers of fibrin on its surface; 11 of 20 were covered with a homogeneous layer. Within this layer a net of collagen fibers was detectable. A major cellular reaction was observed only on IOFB that injured the retina, pigment epithelium and choroid.

CONCLUSIONS

This morphologic study shows that: (1) a fibrin net develops in the vitreous around intravitreal IOFB; (2) depositions of amorphous material into the spaces of this net lead to dense coverage of the IOFB; (3) cellular reactions are not condition for the development of this coverage; (4) laceration of the retina induces a fibrocellular response.

Transient deafness due to temperature-sensitive auditory neuropathy

OBJECTIVE

To define mechanisms accounting for transient deafness in three children (two siblings, ages 3 and 6, and an unrelated child, age 15) when they become febrile.

DESIGN

Audiometric tests (pure-tone audiometry, speech and sentence comprehension), tympanometry, middle ear muscle reflex thresholds, otoacoustic emissions (OAEs), and electrophysiological methods (auditory brain stem responses [ABRs], sensory evoked potentials, peripheral nerve conduction velocities) were used to test the children when they were afebrile and febrile.

RESULTS

ABRs, when afebrile, were abnormal with a profound delay of the IV-V and absence of waves I-III. The ABR in one of the children, tested when febrile, showed no ABR components. Measures of cochlear receptor function using OAEs were normal in both febrile and afebrile states. Cochlear microphonic potentials were present in the three children, and a summating potential was likely present in two. When afebrile, there was a mild threshold elevation for all frequencies in the 15-yr-old and a mild elevation of thresholds for just low frequencies in the two siblings. Speech comprehension in quiet was normal but impaired in noise. One of the siblings tested when febrile had a profound elevation (>80 dB) of pure-tone thresholds and speech comprehension was absent. Acoustic reflexes subserving middle ear muscles and olivocochlear bundle were absent when febrile and when afebrile. No other peripheral or cranial nerve abnormalities were found in any of the children. Sensory nerve action potentials from median nerve in one of the children showed no abnormalities on warming of the hand to 39 degrees C.

CONCLUSION

These children have an auditory neuropathy manifested by a disorder of auditory nerve function in the presence of normal cochlear outer hair cell functions. They develop a conduction block of the auditory nerves when their core body temperature rises due, most likely, to a demyelinating disorder of the auditory nerve. The auditory neuropathy in the two affected siblings is likely to be inherited as a recessive disorder.

Antigastric autoantibodies and gastric secretory function in Helicobacter pylori-infected patients with duodenal ulcer and non-ulcer dyspepsia

BACKGROUND

Autoantibodies against epitopes located at the canaliculi of human parietal cells occur in about 30% of Helicobacter pylori-infected patients. This has led to the hypothesis that gastric secretory function could be inhibited by anticanalicular autoantibodies in H. pylori gastritis.

METHODS

Forty-four H. pylori-infected patients with and without duodenal ulcers were screened for anticanalicular autoantibodies by means of immunohistochemistry. Plasma gastrin levels and basal and maximal gastric acid output were determined.

RESULTS

Fasting gastrin levels were significantly increased in the group with anticanalicular autoantibodies. In the group of patients with non-ulcer dyspepsia the presence of anticanalicular autoantibodies was significantly correlated with an impaired basal acid secretion.

CONCLUSIONS

Antigastric autoimmunity in H. pylori gastritis seems to be relevant for gastric hyposecretion either directly by inhibiting the proton pump or indirectly through the development of gastric mucosa atrophy.

An automated chromogenic peptide substrate assay for coagulation factor XII

We have developed an automated chromogenic peptide substrate assay for factor XII (FXIIcs) on a Cobas Mira S Plus clinical chemistry analyser using a new commercially available kit. This was used to determine factor XII (FXII) levels in plasma samples from 320 blood donors, 206 patients with a history of venous thrombosis and 74 lupus anticoagulant positive (LA+) patients. Results were compared with those obtained in a clotting assay for FXII (FXIIct) and an immunochemical assay (FXIIag). A satisfactory correlation coefficient of 0.92 and a regression line equation of y = 7.898 + 0.871x was obtained between FXIIcs and FXIIct in the 320 blood donors. Levels of FXII below the calculated normal range were found in nine blood donors (2.8%) and 16 venous thrombosis patients (7.8%). The blood donors and patients with venous thrombosis with low FXIIcs values had FXII levels below our lower limits of normal for both FXIIct and FXIIag; all were lupus anticoagulant negative. When FXII levels were determined in the 74 LA+ patients, 27 (36.5%) gave markedly lower FXII values in the FXIIct when compared with the FXIIcs. FXIIag levels corresponded with FXIIcs. The automated FXIIcs assay is therefore lupus anticoagulant insensitive and allows us to measure FXII levels accurately and routinely in large numbers of patient samples.

Effects of Maine's 0.05% legal blood alcohol level for drivers with DWI convictions

OBJECTIVE

To determine whether a Maine law lowering the legal blood alcohol limit (BAL) from 0.10% to 0.05% for people convicted of driving while intoxicated (DWI) reduced the involvement of this group in fatal crashes.

METHODS

The authors calculated changes in the proportions of fatal crashes involving drivers with prior DWI convictions from the six-year period before enactment of the law to the six-year period following enactment of the law, comparing Maine with the other New England states.

RESULTS

In Maine, the proportion of fetal crashes involving drivers with recorded prior DWI convictions declined 25% following passage of the 0.05% DWI law, while the proportion rose in the rest of New England during the same years. The proportion of fatal crashes involving drivers with recorded prior DWI convictions and illegal alcohol levels also declined significantly in Maine, as did the proportion of fatal crashes involving fatally injured drivers with recorded prior DWI convictions and illegal alcohol levels. Most of the latter decline was due to a decline in alcohol-related fatalities of previously convicted drivers with very high BALs, of 0.15% or higher, at the time of the fatal crash. Each of these declines in Maine was significant relative to the rest of New England.

CONCLUSION

Other states should consider instituting 0.05% BAL limits for convicted DWI offenders.

Factor XII determinations in the presence and absence of phospholipid antibodies

Factor XII (FXII) levels were determined in plasma samples from 29 normal donors, 10 patients with inherited FXII deficiency (all lupus anticoagulant [LA] negative) and 67 LA positive patients, using clotting (FXIIct), chromogenic substrate (FXIIcs) and immunochemical (FXIIag) assays. Excellent correlations were obtained in the three FXII assays with the LA negative samples and between the FXIIcs and FXIIag assays in the LA positive samples. Correlations between both the FXIIcs and FXIIag with FXIIct in the LA positive patients were poor. Of 67 LA positive samples studied, 25 (37.3%) showed lower values in the FXIIct assay; 13 (19.4%) of these patients were pseudo FXII deficient with values of FXII below the lower limit of normal. These results indicate that a diagnosis of FXII deficiency can be made inappropriately in the presence of phospholipid antibodies and that such a diagnosis should not be made by FXIIct assay alone.

[ORBIT-NET. Discussion forum on orbitology on the internet]

INTRODUCTION

A basic service in the public network "Internet" is electronic mail (e-mail). E-mail makes the participation in discussion groups possible by mailing contributions to the discussion to all members electronically. To complement the existing list of ophthalmologic discussion groups ORBIT-NET was introduced. It offers experts in research, clinic, diagnostic and therapy of orbital diseases the opportunity to make queries or present interesting casuistries and to ask for comments, differential diagnosis or advice on therapy. Other participants can be made aware of new scientific results, actual publications or meetings.

MATERIAL AND METHODS

For participation a computer, a modem, an Internet-Provider and special software are required. Registration is made either by e-mail or regular mail. A verification is necessary to limit the list of participants to experts.

RESULTS

Since the introduction of ORBIT-NET on November 9th, 1996, there have been no technical problems. ORBIT-NET has been effective as a platform.

CONCLUSIONS

The international, interdisciplinary platform ORBIT-NET is an addition to the existing ophthalmologic discussion groups. ORBIT-NET offers orbitologists an international discussion of results and diagnosis, supports further training and can give encouragement to further research.

Impaired motor cortex inhibition in patients with amyotrophic lateral sclerosis. Evidence from paired transcranial magnetic stimulation

We investigated 14 patients with amyotrophic lateral sclerosis (ALS) by paired conditioning-test transcranial magnetic stimulation to test the hypothesis that the motor cortex is hyperexcitable in ALS. Intracortical (corticocortical) inhibition was significantly less in the ALS group than in an age-matched healthy control group (85.3 +/- 27.0% versus 45.2 +/- 15.5%, respectively; p < 0.0001). In contrast, intracortical facilitation, motor threshold, and cortical silent period duration in the ALS patients were not different from the control group. We suggest that the selective abnormality of intracortical inhibition is best compatible with an impaired function of inhibitory interneuronal circuits in the motor cortex that in turn renders the corticomotoneuron hyperexcitable.

[Pharmacologic intolerance reaction after intravenous injection of pethidine]

We report on anaphylactoid reactions (urticae at the injection site and along the injection vein) after intravenous injections of pethidine in two patients. Skin tests with pethidine were negative, but intravenous challenge showed urticae. These results indicate that the reactions were due to a non-immunological mechanism resembling pharmacological intolerance. Retrospective analysis revealed a 5.6% incidence of pharmacological intolerance reactions to intravenous pethidine in 519 patients.

Bilateral Cataract after Phakic Posterior Chamber Top Hat-style Silicone Intraocular Lens

BACKGROUND

New strategies have been developed for surgical treatment of high myopia. Recently, implantation of minus power posterior chamber intraocular lenses (IOL) into phakic eyes has been introduced.

METHODS

We report a 37 year-old female patient who developed bilateral anterior subcapsular cataract 7 years after minus-power, top hat-style silicone posterior chamber IOL implantation in Russia. The corrected visual acuity was right eye 20/200 and left eye 20/63. Because of the high myopia and the posterior chamber IOL in her phakic eyes, biometry for IOL calculation gave contradictory results. Both posterior chamber IOLs were found to be adherent to the crystalline lenses. After posterior chamber IOL explantation and phacoemulsification, intraoperative retinoscopy was performed. With this aphakic refraction, the IOL power was calculated and implanted. The explanted posterior chamber IOLs were examined by scanning electron microscopy.

RESULTS

After bilateral operation the corrected visual acuity increased to right eye 20/32 and left eye 20/40, respectively. On scanning electron microscopy, a membranous structure of unknown origin was noted on the entire surface of the explanted posterior chamber IOLS.

CONCLUSION

There is a potential risk of cataract formation after implantation of this top hat-style silicone posterior chamber IOL. If cataract extraction in this specific situation is needed, a different approach for calculating the aphakic IOL power is necessary, such as intraoperative retinoscopy.