[One-year results on the safety and efficacy of the InnFocus MicroShunt™ depending on placement and concentration of mitomycin C]. / Résultats à un an de l'efficacité et de l'innocuité du MicroShunt InnFocus selon l'emplacement et la concentration de MMC.

PURPOSE: To compare intraocular pressure (IOP) at one year with the InnFocus MicroShunt(®) with or without cataract surgery with according to placement and concentration of mitomycin C (MMC) DESIGN: A retrospective two-center, two-surgeon study (France and Dominican Republic). PATIENTS AND METHODS: Adults with POAG requiring filtering surgery. One MicroShunt(®) was placed in one eye of each patient. The effect of concentration and site of application of MMC was assessed by IOP and medication reduction at one year. RESULTS: Eighty-seven eyes were studied with one-year follow-up. Twenty-three eyes treated with 0.4 mg/mL MMC close to the limbus demonstrated a 55% reduction in IOP from 23.8 ± 5.3 at baseline to 10.7 ± 2.8 mmHg at one year. Topical glaucoma medication/patient was reduced 85% from 2.4 ± 0.9 to 0.3 ± 0.8. Thirty-one eyes treated with 0.2mg/mL MMC close to the limbus demonstrated a 52% reduction in IOP from 27.9 ± 6.7 at baseline to 13.3 ± 3.3 mmHg at one year. Topical glaucoma medication/patient was reduced 88% from 2.5 ± 1.4 to 0.5 ± 1.0. Thirty-three eyes treated with 0.4 mg/mL MMC deep in the pocket demonstrated a 38% reduction in IOP from 25.4 ± 7.9 at baseline to 15.7 ± 4.6 mmHg at one year. Topical glaucoma medication/patient was reduced 72% from 2.9 ± 1.0 to 0.8 ± 1.3. There were no sight-threatening long-term adverse events. CONCLUSION: The InnFocus MicroShunt(®) is a filtering surgery whose efficacy is related to the location of application and concentration of MMC used.

Wound healing response in the presence of stromal irregularities after excimer laser treatment.

PURPOSE: To trace the fate of stromal irregularities after excimer laser treatment and to increase our knowledge of the reasons why surface irregularities in the ablation bed cause inferior postoperative results. METHODS: Twelve New Zealand White rabbits received a transepithelial photoablation to a preset depth of 60 microm. An electron microscopy specimen grid was then placed on the denuded stroma and another 20 microm ablation was applied in order to produce surface irregularities. Another six rabbits received a plano transepithelial photoablation to a preset depth of 80 microm. The treated corneas were harvested at various timepoints and differentially further processed for microradiography, hematoxylin-eosin -, hyaluronan (HA)- and leukocyte protein L1 staining. RESULTS: In the grid treated corneas the subepithelial mesh pattern is clearly discernible after 1 week, and after 4 weeks it is replaced by a subepithelial layer containing HA and water. The thinning of this layer between 1 and 12 weeks is statistically significant (p<0.05). After 4 and 8 week the plano treated corneas only exhibit some subepithelial HA- and water accumulation. After 1 day the grid treated corneas show an extensive stromal infiltration of leukocytes. In the plano treated corneas the leukocytes mainly remain on the surface. CONCLUSIONS: During the healing process stromal irregularities are flattened, leaving a homogeneous zone with increased water content. This subepithelial layer is rarefying as new subepithelial tissue is forming. Postablational irregularities induce a more pronounced healing reaction when compared to a smooth ablation surface. Leukocyte infiltration seems to play a role in this process.

Short-term impact of corticosteroids on hyaluronan and epithelial hyperplasia in the rabbit cornea after photorefractive keratectomy.

PURPOSE: To investigate the impact of corticosteroids on subepithelial hyaluronan deposition and corneal epithelium thickness in the first 10 days after photorefractive keratectomy (PRK) and to analyze a possible contralateral effect of corticosteroids. METHODS: Thirty-two New Zealand white rabbits were assigned into two groups and had a transepithelial 5.0-mm diameter, 8.00-diopter myopic PRK performed on one eye. The corticosteroid treatment group (16 animals) received 0.1 mL of methylprednisolone 4% subconjunctivally on the operation table, followed by 0.1% dexamethasone eye drops six times a day during the postoperative period. The sodium chloride (NaCl) treatment group received topical isotonic NaCl eye drops six times a day. In each treatment group, eight animals were killed after 3 and 9 days, respectively. The harvested specimens were stained for hyaluronan and the epithelial thickness was measured. RESULTS: In contrast to the epithelial thickness, the subepithelial hyaluronan did not show a significant increase during the observation period. The corticosteroid treated group showed at both time-points significantly less subepithelial hyaluronan formation as well as a significantly thinner epithelium, when compared with the NaCl-treated group. At 9 days, the corticosteroid-treated group showed a mild epithelial hyperplasia in only one of eight eyes, whereas this was a common finding in the NaCl-treated group. We detected no hyaluronan deposits in any contralateral-untreated eye, and the epithelial thickness did not differ significantly between any of the four contralateral-untreated eye groups. CONCLUSIONS: Corticosteroid medication during the first 10 days after operation reduces the amount of subepithelial hyaluronan production and inhibits the epithelial proliferation, and epithelial hyperplasia is prevented. Neither a contralateral hyaluronan deposition nor a contralateral corticosteroid effect could be detected.

The controversy of prostate screening.

Within the context of aging and ageism, this article evaluates current research on the benefits and risks of prostate cancer screening. Prostate cancer is a concern for many men because it often strikes in the prime of life. Prostate cancer is the most common form of cancer in American men and the second leading cause of cancer-related mortality after lung cancer. Although the disease can be cured if discovered early, it is a slow-growing malignancy that leads to an agonizing death if left untreated. Differential diagnosis often is complicated by comorbid conditions that are part of the normal aging process. Moreover, practitioners' judgment often is prejudiced by common aging misconceptions. Despite the benefits of early screening and detection, the benefits of screening initiatives remain controversial.

Exploring the efficacy of support groups for men with prostrate cancer.

For the 180,000 men who will be diagnosed with prostate cancer this year, improvements in the disease's medical management have prolonged life expectancy. Long-standing treatment side effects include bowel and urinary incontinence and erectile dysfunction, which frequently are embarrassing and contribute to poor emotional well-being. Despite the popularity of support groups in alleviating emotional symptoms related to cancer and its treatment, few men participate in such groups. This article focuses on the reasons why men do not find support groups appealing and presents alternatives that may be more acceptable. Suggestions are made for clinical and research implications.

Plano and refractive keratectomy. Comparison of the wound healing response.

PURPOSE: To compare the extension of the subepithelial low dry mass layer after plano and refractive keratectomy, in order to know more about the factors that influence the corneal wound healing response. METHODS: Thirty rabbits assigned into two groups were treated on one eye each with plano and refractive keratectomy, respectively. In each group five rabbits were sacrificed after 10 days, 4 weeks and 21 weeks, respectively. The corneal buttons were excised, freeze-sectioned and freeze-dried. On the freeze-dried sections microradiography was performed. In the treated eyes the superficial stroma showed qualitatively underneath the epithelium areas with low dry mass, whose extension was measured by a modified planimetry. RESULTS: The difference between the extension of subepithelial low dry mass areas in the plano and the refractive keratectomy group was small but statistically significant at 4 weeks. Within the refractive group the extension of low dry mass was significantly higher at 4 weeks compared to 21 weeks. CONCLUSION: A flat surface ablation may cause a less pronounced healing response when compared to a steep curve refractive treatment.

The arbZ gene from Lactobacillus delbrueckii subsp. lactis confers to Escherichia coli the ability to utilize the beta-glucoside arbutin.

From a genomic library of the industrially used strain Lactobacillus delbrueckii subsp. lactis DSM7290, a gene designated arbZ (869bp; encoding a 33.5kDa protein) was isolated by screening E. coli transformants for the ability to utilize the beta-glucoside arbutin. Out of 9000 transformants nine were able to ferment arbutin, whereas no utilization of the beta-glucosides salicin, esculin or cellobiose could be detected. Overexpression of arbZ using the T7-polymerase-T7-promoter-system resulted in the formation of insoluble, catalytically inactive protein aggregates (inclusion bodies). Accordingly, overexpression was not accompanied by an increase in ArbZ activity. Induction of arbZ controlled by the lac promoter under conditions that reduce protein aggregation resulted in a 12-fold increase in arbutin hydrolyzing activity of intact cells and a 13-fold increase in phospho-beta-glycosidase activity in cell-free extracts of the respective transformants. Nucleotide sequence analysis revealed a second gene upstream of arbZ that was designated arbX (830bp). ArbX (32.6kDa) shared similarity with several glycosyltransferases involved in the biosynthesis of lipopolysaccharides in Gram-negative bacteria. In Lb. delbrueckii subsp. lactis DSM7290 two transcripts, one covering arbX together with arbZ and one covering arbZ alone were detected by Northern blot analysis.

Colocalization of hyaluronan and water in rabbit corneas after photorefractive keratectomy by specific staining for hyaluronan and by quantitative microradiography.

PURPOSE: Endogenous hyaluronan (HA) has previously been shown to be a part of corneal wound healing after photorefractive keratectomy (PRK). HA is known to bind considerable amounts of water. This study aimed to show whether HA colocalized with water in the wound area after PRK. METHODS: Five New Zealand White rabbits were subjected to PRK in one eye each. After 4 weeks, the rabbits were killed and the corneas were freeze-sectioned. The freeze-dried sections were exposed to soft x-rays generated at 3 kV and the microradiographs were evaluated densitometrically. The same sections were then stained for the presence of HA using the HA-binding region of bovine nasal cartilage proteoglycans linked to biotin. RESULTS: The microradiographs showed, in a zone underlying the epithelium, that the water content was increased. In the corresponding zone, the cornea stained positive for HA. CONCLUSION: HA that is reactively formed in the corneal wound after PRK colocalized to the hydrated area of the corresponding location as revealed by quantitative microradiography. The findings suggest that HA causes local shifts in water content in the corneal wound and thereby also local shifts in transparency.

A Corethane/polyester composite vascular prosthesis for vascular access. Comparison with expanded polytetrafluoroethylene grafts in a canine model.

An important need in hemodialysis is a self-sealing prosthesis for vascular access with at least equivalent patency and biostability to expanded polytetrafluoroethylene (ePTFE) alternatives. The authors have developed a Corethane/polyester composite (CPC) graft with an inner blood interfacing layer of spun Corethane fibers (10-15 microns diameter; pore size 30-60 microns) impregnated with a gelatin-heparin complex and an outer soft tissue interfacing warp-knitted polyester sheath. Twenty-six CPC grafts (6 mm internal diameter; 25-30 cm length) and eight Gore-Tex ePTFE grafts (same dimensions) were implanted as femoral artery-to-vein shunts in dogs on low dose (162 mg/day) aspirin, and subjected to weekly dialysis needle punctures for up to 52 weeks. Patency was 73% (19/26 with 15 at 52 weeks) for the CPC grafts and 63% (5/8 at 52 weeks) for the ePTFE controls, with more favorable healing (e.g., less extensive mural thrombi) of the CPC grafts. The hemostasis time per needle pair after removal (3.1 min mean for CPC versus 21.2 min mean for ePTFE) and the blood loss in achieving hemostasis (5.7 g mean for CPC versus 47.9 g for ePTFE) documented the significant (p < 0.0001) performance advantages of the CPC prosthesis.

Use of maximum length sequence analysis in newborn hearing testing.

The use of maximum length sequence analysis (MLSA) with rapid click rates may be of clinical value in newborn hearing screening because a greater number of individual responses can be signal averaged without adding to test time. To examine the potential clinical value of MLSA in newborn screening, auditory brainstem responses (ABRs) from 50 premature newborns were studied. ABRs were acquired with conventional signal averaging at four stimulus intensity levels (50 dB, 40 dB, 30 dB, and 20 dB nHL) using a click rate of 33.3/sec. These responses were directly compared with the ABRs acquired with MLSA using a rate of 227.3/sec. MLSA and conventional signal averaging yielded similar results with no statistically significant differences in the number of responses detected. Across babies, the overall quality of the tracings slightly favored MLSA, particularly when recording conditions were poor. Though the results of this investigation do not support the use of MLSA as the primary technique in newborn screening in the neonatal intensive care unit (NICU), they do support consideration of the use of MLSA as an alternative technique when the responses obtained with conventional signal averaging are poorly defined.

A compliant Corethane/Dacron composite vascular prosthesis. Comparison with 4-mm ePTFE grafts in a canine model.

We have developed a composite vascular prosthesis with the inner blood interfacing layer made of a porous elastomeric membrane of spun Corethane fibers (10-15 microns in diameter, pore size 30-60 microns) impregnated with a gelatin-heparin complex and an outer soft tissue interfacing warp knitted Dacron sheath. Forty-eight Corethane/Dacron composite (CDC) vascular grafts, 4 mm in diameter and 5 cm in length, and 48 expanded polytetrafluoroethylene (ePTFE) vascular grafts of similar size were implanted bilaterally as end to end interposition grafts on opposite sides in the carotid and femoral arteries in dogs on low dose (162 mg/day) aspirin. Patency at 3 months was 37/48 (77%) for the ePTFE grafts and 44/48 (91.7%) for the CDC grafts. Fisher's exact test (two-tailed comparison) indicates the probability of superior CDC graft patency to be 95.5%. In the seven pairs of grafts in which one graft was occluded and the contralateral graft of another type was patent, the CDC graft was patent and the ePTFE graft was occluded in every instance. Explant histology and scanning electron microscopy showed greater collagenization, less residual platelet-fibrin and red blood cell deposits, and more frequent mid-graft endothelialization in the CDC grafts than in the ePTFE grafts.

Application of maximum length sequence analysis to auditory brainstem response testing of premature newborns.

The feasibility of utilizing maximum length sequence analysis (MLSA) with newborns was examined on 40 premature infants residing in a neonatal intensive care unit (NICU). Auditory brainstem responses (ABRs) were initially obtained using a conventional stimulus rate of 33.3/sec. Using MLSA, responses were also recorded using much faster stimulus rates (227.3/sec, 454.5/sec, and 909.1/sec). As expected, faster stimulus rates resulted in longer ABR component wave latencies. Less expected was the clarity of the ABRs that were obtained through MLSA. Well-defined responses were obtained from premature infants at all stimulus rates. The findings suggest that MLSA may have clinical applications to newborn hearing screening.

Swallowing, speech, and brainstem auditory-evoked potentials in spasmodic torticollis.

To explore the controversial "brainstem theory" of spasmodic torticollis, eight consecutively referred patients were examined. Three independent examinations were conducted on the same day: a videofluoroscopic barium swallowing examination, an instrumental speech examination, and a brainstem auditory-evoked potential (BAEP) analysis. Swallowing was normal in two patients; speech physiology, in five; and BAEPs, in all. Normal BAEPs refute the brainstem theory, while abnormalities of speech and swallowing temper this conclusion. Several alternative explanations are proposed.

Application of an implantable bone conduction hearing device to patients with unilateral sensorineural hearing loss.

This investigation, comprised of five studies, was undertaken to determine if individuals with newly acquired profound unilateral hearing losses would benefit from an implantable bone-conduction hearing device. The bone conductor was implanted on the side of the deaf ear at the time of translabyrinthine acoustic tumor resection. Two areas greatly affected by unilateral hearing loss, speech recognition in noise and sound localization, were examined. No improvement in aided performance could be documented in either area.

The composite Corethane/Dacron vascular prosthesis. Canine in vivo evaluation of 4 mm diameter grafts with 1 year follow-up.

Polyurethane vascular prostheses offer the potential of superior thromboresistance and reduced anastomotic hyperplasia compared to existing Dacron and ePTFE alternatives, but have suffered from susceptibility to biodegradation, with resulting mechanical failure. To address this problem, the authors have developed and evaluated a composite prosthesis comprised of: 1) an inner blood interfacing elastomeric porous membrane made from Corethane, a proprietary Shore 80A polyurethane like material substantially devoid of ether/ester linkages, with superior biostability over conventional polyether urethanes, spun into a nonwoven structure with fiber diameters 10-15 microns and pore sizes 30-60 microns filled with gelatin +/- heparin; and 2) an outer soft, tissue interfacing, warp knitted Dacron mesh bonded to the inner layer to assure long-term dimensional stability. Twenty 4 mm ID x 5 cm L composite prostheses, half with heparinized gelatin (the remainder nonheparinized) were implanted as femoral interposition grafts in 10 dogs. Four of the 10 nonheparinized grafts occluded. All 10 with heparin remained widely patent, with two explanted at 6 months showing vascularized connective tissue growth through the graft, in contrast to the giant cell inflammatory response to the Dacron mesh, with a substantially endothelialized neointima and no Corethane biodegradation. Of the 10 patent grafts at 1 year follow-up, none showed aneurysm formation. This vascular prosthesis provides compliance superior to ePTFE and Dacron alternatives, with excellent suture retention and good kink resistance, while combining the superior thromboresistance and tissue ingrowth properties of polyurethanes with the proven biostability of Dacron.

Implantable bone-conduction hearing device: practical considerations.

An implantable bone conduction hearing device can be of significant benefit to carefully selected patients with noncorrectable conductive hearing losses. However, for some patients the device has significant limitations. This paper presents several practical issues that need to be considered before a decision is made regarding implant surgery. It is recommended that, whenever possible, air conduction hearing aids remain the first option considered when a patient's conductive hearing loss cannot be resolved through traditional medical management.

Comparative studies of speech processing strategies for cochlear implants.

A wide variety of speech processing strategies for multichannel auditory prostheses were compared in studies of two patients implanted with the UCSF electrode array. Each strategy was evaluated using tests of vowel and consonant confusions, with and without lipreading. Included among the strategies were the compressed analog processor of the present UCSF/Storz prosthesis and a group of interleaved pulses processors in which the amplitudes of nonsimultaneous pulses code the spectral variations of speech. For these patients, each with indications of poor nerve survival, test scores were significantly higher with the interleaved pulses processors. We believe this superior performance was a result of 1. the substantial release from channel interactions provided by nonsimultaneous stimuli and 2. a fast enough rotation among the channels to support adequate temporal and spectral resolution of perceived speech sounds.