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PubMed1998

Position of poly(methyl methacrylate) and silicone intraocular lenses after phacoemulsification.

PURPOSE: To compare the positional change of poly(methyl methacrylate) (PMMA) and silicone intraocular lenses (IOLs) in vivo after phacoemulsification. SETTING: Taipei Municipal Yang-Ming Hospital, Taipei, Taiwan. METHODS: A prospective study of 70 cataractous eyes treated by phacoemulsification with IOL implantation was carried out. The eyes were randomized into 2 groups based on IOL type: 1-piece PMMA IOL; 3-piece silicone IOL. The amount of IOL tilt and decentration was measured and anterior chamber depth (ACD) determined by Scheimpflug photography using an anterior eye segment analysis system (EAS-1000, Nidek). All eyes were examined 1 week and 1 to 6 months after surgery. RESULTS: No statistically significantly differences were found in the amount of tilt and decentration between 2 IOL types throughout the study. The ACDs were relatively constant in both groups through the early postoperative periods. CONCLUSION: The stability of PMMA and silicone IOLs were the same after phacoemulsification.

Aged↗
PubMed1999

Corneal topography of small-beam tracking excimer laser photorefractive keratectomy.

PURPOSE: To evaluate the topographic characteristic of photorefractive keratectomy (PRK) for low myopia performed with a small-beam (0.9 mm) tracking excimer laser. SETTING: Department of Ophthalmology, LSU Eye Center, Louisiana State University Medical Center School of Medicine in New Orleans, and the Refractive Surgery Center of the South at the Eye, Ear, Nose, & Throat Hospital, New Orleans, Louisiana, USA. METHODS: Sixty-seven eyes of 47 patients had PRK with a small-beam tracking laser. Of these, 49 eyes had data permitting evaluation of ablation centration; usable data for topographic analysis were available for 59 eyes preoperatively, 54 eyes at 1 month, 42 eyes at 3 months, and 25 eyes at 6 months, permitting measurement of various topographic parameters, including the cylinder (CYL), average corneal power (ACP), surface regularity index (SRI), surface asymmetry index (SAI), corneal eccentricity index (CEI), and coefficient of variation of corneal power (CVP). RESULTS: Preoperatively, all eyes were topographically normal. Postoperatively, no eye exhibited a "central island" by even the least-restrictive definition, and all eyes had best spectacle-corrected visual acuities (BSCVAs) of 20/20 or better at all follow-ups. Mean decentration of the ablations from the pupil centers was 0.42 mm +/- 0.28 (SD) (n = 49). There was no correlation between measured decentration and BSCVA (P = .46). The central cornea was flattened (decreased ACP; P < .001) and made oblate (decreased CEI; P < .001) as expected. There was no increase in SRI or SAI (irregular astigmatism) at 6 months compared with preoperative values (P = .91); however, CYL and CVP (varifocality) increased slightly (P = .04 and .02, respectively). CONCLUSION: The absence of significant regular or irregular astigmatism 6 months after PRK with the small-beam laser is an improvement over published results achieved with wide-beam lasers and is consistent with the excellent visual acuity results in this cohort.

Cornea↗
PubMed1993

Neurochemistry, connectivity and plasticity of small intensely fluorescent (SIF) cells in the rat superior cervical ganglion.

Applying double-labelling immunofluorescence, the peptide content of solitary and clustered small intensely fluorescent (SIF) cells, identified by an antiserum to a selective membrane glycoprotein marker, synaptophysin, was correlated with the presence of catecholamines in the rat superior cervical ganglion. Most of synaptophysin-immunoreactive solitary and clustered SIF cells apparently contained dopamine (indicated by tyrosine hydroxylase-TH) but not noradrenaline (indicated by dopamine-beta-hydroxylase-DBH). Frequently, immunoreactivities for substance P or rarely, neuropeptide Y were colocalized in TH-immunolabeled cells of both types. Immunostaining for vasoactive intestinal polypeptide was found only in solitary SIF cells and was visible in TH-immunoreactive, as well as in TH-nonreactive cells. Very few solitary SIF cells were TH- and DBH-immunoreactive. Solitary and clustered SIF cells, as a rule, were encircled by leu-enkephalin-positive fibres which were also met-enkephalin-arg6-phe7-immunoreactive, indicating proenkephalin as precursor. SIF cells were additionally approached by varicose fibres which contained immunoreactivity for calcitonin gene-related peptide (CGRP) but not for enkephalins. As observed by immuno-electronmicroscopy, fibres that were immunostained for leu-enkephalin or CGRP, deeply invaginated into SIF cell somata. In addition to close membrane appositions, CGRP-immunolabeled fibres exhibited efferent synaptic contacts wih elements of SIF cell clusters. SIF cells were non-reactive to enkephalin-antisera in control ganglia and after transection of the postganglionic nerves (axotomy); but both types exhibited leu-enkephalin in preganglionically transected ganglia (decentralization) in which enkephalin-immunoreactive fibre baskets were absent. Synthesis of enkephalin in SIF cells after decentralization was confirmed by in situ hybridization demonstrating intracytoplasmic proenkephalin messenger-RNA. The findings are indicative for a differential neurochemical equipment of SIF cells in the rat superior cervical ganglion, which mainly is independent to a topographical classification. Moreover, they demonstrate the involvement of two neuropeptides in preganglionic SIF cell innervation. Finally, the observations indicate the capacity of SIF cells for proenkephalin-expression in response to preganglionic denervation.

Animals↗
PubMed2003

Transport and survival of bacterial and viral tracers through submerged-flow constructed wetland and sand-filter system.

Untreated or improperly treated wastewater has often been cited as the primary contamination source of groundwater. The use of decentralized wastewater treatment systems has applicability around the world since it obviates the need for extensive infrastructure development and expenditures. The use of a submerged flow constructed wetland (CW) and a sand filter to remove bacterial and viral pathogens from wastewater streams was evaluated in this study Salmonella sp. and a bacteriophages tracer were used in conjunction with the conservative bromide tracer to understand the fate and transport of these organisms in these treatment systems. Viral breakthrough numbers in the sand filter and CW were similar with a Spearman Rank correlation of 0.8 (P<0.05). In the CW, the virus exhibited almost a 3-log reduction, while in the sand filter, the viruses exhibited a 2-log reduction. The bacterial tracers, however, did not exhibit similar reductions. Low numbers of bacteria and viruses were still detectable in the effluent streams suggesting that disinfection of the effluent is critical. The survival of the tracer bacteria and viruses was as expected dependent on the biotic and abiotic conditions existing within the wastewater. The results suggest that the microbial removal characteristics of decentralized wastewater treatment systems can vary and depend on factors such as adsorption, desorption and inactivation which in turn depend on the design specifics such as filter media characteristics and local climatic conditions.

Bacteriophages↗
PubMed2001

Topographical mapping and in-office modification in the management of an orthokeratology patient.

A 20-year-old female was fitted with rigid gas permeable (RGP) orthokeratology (ortho-k) lenses for overnight wear. Both lenses decentred nasally due to the tight fit of the alignment zone (AZ) and the peripheral zone (PZ). The AZ and PZ of both lenses were flattened using an in-office modification unit. Centration of the right lens improved but a small central island was also observed. The left lens still decentred nasally. Both findings indicated that the AZ and PZ of the right lens were too steep leading to 'lens vaulting' or excessive central clearance and inadequate tear exchange, respectively. The AZ and PZ of both lenses were flattened further using the modification unit and after the adjustment, both lenses centred well and the central island in the right eye was eliminated. This case demonstrates the usefulness of topographical corneal mapping and in-office modification of lenses in the management of ortho-k patients.

Journal Article↗
PubMed2003

Ultrasound-guided botulinum toxin injection technique for the iliopsoas muscle.

Intramuscular botulinum toxin A injections are beneficial for the treatment of functional shortening of the iliopsoas muscle, but it is difficult to achieve precise needle positioning and injection. As a solution to this we present an ultrasound-guided injection technique for the iliopsoas muscle using an anterior approach from the groin. The procedure was performed 26 times in 13 patients (seven males, six females; mean age 11 years, SD 9 years 8 months; age range 4 to 31 years), 10 times bilaterally. Indications were functional iliopsoas shortening due to cerebral palsy (17 hips), hereditary spastic paraplegia (four hips), and Perthes disease (five hips). In all cases the iliopsoas muscle was identified easily by ultrasound; the placement of the injection needle and injection into the site of interest were observed during real time. No complications were encountered. Botulinum toxin A (BTX-A) injections have become established as a standard procedure for the treatment of functional shortening of different muscles in persons with spasticity or dystonia (Kessler et al. 1999, Bakheit et al. 2001, Kirschner et al. 2001). Optimal needle placement is essential to avoid severe side effects and to assess lack of response to the drug or incorrect region of injection. While injection into superficial, very palpable muscles is quite easy, the approach to other muscles such as the iliopsoas muscle may be more difficult and the placement of the needle for an optimal injection site is harder to control. As a solution to this, we present an ultrasound-guided injection technique. The main indications for BTX-A injections in the iliopsoas muscle are dynamic hip flexion deformities mostly due to spastic conditions which may compromise walking (increased anterior pelvic tilt during the whole gait cycle, decreased hip extension at terminal stance, increased peak hip flexion during swing; Molenaers et al. 1999. Another indication might be decentration of the femoral head (as part of an injection programme which also includes other muscles like the adductors and the medial hamstrings) for pain relief, reducing care difficulties and, possibly, prevention of further decentration (Porta 2000, Foster et al. 2001, Deleplanque et al. 2002, Lubik et al. 2002). In Perthes disease, BTX-A injections in the iliopsoas muscle and the adductors may prevent a fixed deformity, which is a negative prognostic factor.

Adult↗
PubMed1987

Rationing medical technology. Hospital decision making in the United States and England.

This paper analyzes medical technology decision making in the United States and England in terms of the appropriateness of different decision-making models to the organization and delivery of medical care, and to the rationing of technology among and within hospitals. It examines the effect on the American hospital of prospective payment programs from the perspective of organizational structure and decision making. The strategies of central control and specification which characterize these programs are contrasted with decision-making procedures in the English National Health Service, which have emphasized decentralization, delegation, and consensus. The analysis suggests that decentralized models of decision making are more supportive of essential elements of medical care including doctor-patient trust and professional responsibility and are more able to achieve rationing decisions which are compatible with professional and consumer preferences.

Data Collection↗
PubMed2000

Health technology assessment in Italy.

Italy has a national health service (SSN) dating to 1978. Italy's system of government is characterized by a rather high degree of decentralization of power, and the health system is likewise decentralized. Most of the responsibilities for health care have been ceded to the regions. The state retains only limited coordinating and supervisory powers. The state has a financial responsibility for the national health service, but state contributions are limited and expenditures in excess of this made by the region must be financed from other sources. Health reforms of 1992-93 aimed at making the regions more sensitive to the need to control aggregate expenditure and to monitor measures to promote efficiency, quality, and citizen-patient satisfaction. The diffusion of individual health technologies has been relatively uncontrolled in many regions in Italy, although tight central constraints on capital spending have contained diffusion of new technology. Regulation of placement of services is a planning function and is the responsibility of both the Ministry of Health and the regions. Health technology assessment (HTA) activities have been expanding since the early 1990s, but these activities tend to be untargeted, uncoordinated, and without priorities. Nonetheless, the principal actors in the SSN at national, regional, and local levels are becoming more sensitive to the need to apply criteria of clinical and cost-effectiveness and to be more rigorous in deciding what services to guarantee. There are reasons to be guardedly optimistic about the future of HTA in Italy.

Delivery of Health Care↗
PubMed2000

Health technology assessment in Switzerland.

Switzerland has a mixed public and private healthcare system. All citizens are enrolled in compulsory basic health insurance. A 1996 law allows people to choose among different sickness funds and managed care plans. The federal government is empowered to act on important health issues, but the 26 cantons have prime responsibility in health care and social welfare. They have their own laws on health care, hygiene, hospitals, and social welfare. These laws are not harmonized. The system is complex, with a mix of public (mainly hospitals) and private (mainly doctors' offices) providers. The health services are decentralized. Ambulatory care was traditionally provided in doctors' offices, but the last decade has seen the development of centers for day surgery, group practices, and managed care plans. Decisions on placement, location, and extension of services are decentralized. The payment system is very complex. Current trends include global budgets, cost analyses, and prices related to patient categories. However, coverage policy is developed centrally and includes both traditionally established services and new technologies. New technologies are added to the list only after evaluation by the Federal Coverage Committee. The coverage process integrates health technology assessment (HTA). Coverage can be granted in stages, including limited coverage and temporary coverage. Technologies and coverage can be reevaluated on the basis of registries or assessment information. The structure of the Swiss healthcare system does not lend itself to the establishment of a national HTA program. However, recent moves include the development of a coordinating mechanism for HTA in Switzerland.

Delivery of Health Care↗
PubMed1998

Thick-film electrochemical immunosensor based on stripping potentiometric detection of a metal ion label.

A disposable electrochemical immunosensor based on potentiometric stripping analysis (PSA) of a metal tracer and using an entirely on-chip assay format is demonstrated. Challenges associated with the adaptation of earlier stripping voltammetric immunoassays to an on-chip operation, and with meeting the demands of decentralized testing, have been addressed. These include the surface immobilization of the antibody, the replacement of mercury drop electrodes, elimination of the separation and oxygen-removal steps, and the use of quiescent 30-microL sample droplets. Human serum albumin (HSA) and anti-HSA antibody were used as a model system, while bismuth ion served as the metal label. The anti-HSA was immobilized onto the surface of a thick-film electrode, followed by a competition between the Bi-labeled analyte-tracer and the analyte (HSA) for the antibody binding sites. Upon removal of the unbound tracer, Bi3+ was released and detected by PSA. The dynamic concentration range for HSA (0.3-30 micrograms/mL) and the detection limit (0.2 microgram/mL, i.e., 90 fmol in the 30-microL sample) indicate that the greatly simplified protocol does not compromise the performance characteristics of stripping immunoassays. Consequently, this on-chip operation offers great promise for decentralized (clinical and environmental) applications.

Biosensing Techniques↗
PubMed1999

Is scleral fixation a safe procedure for intraocular lens implantation?

PURPOSE: No consensus currently exists on the optimal method for intraocular (IOL) implantation without capsular support. We evaluated the outcome and angiographic findings of eyes that underwent the implantation of scleral fixated IOLs. METHODS: Iris and retinal fluorescein angiography were performed in 13 eyes that had received posterior chamber IOL implantation with scleral fixation. Follow-up examinations also assessed visual acuity (VA), intraocular pressure (IOP), IOL decentration and complications related to the procedure. RESULTS: Mean visual acuity was 0.29 preoperatively and 0.71 postoperatively after a mean follow-up of 14.2 months. A best corrected visual acuity of 0.5 or better was obtained in 12 eyes. Iris fluorescein angiography did not show major vascular abnormalities. Retinal angiography showed 5 cases of macular edema. In 6 eyes light-induced retinal lesions occurred. Cellophane maculopathy was disclosed in 4 eyes. Macular edema was associated with photic injury in 4 cases and with cellophane maculopathy in 2 cases. Mean postoperative visual acuity was 0.6 in eyes with macular edema and 0.88 in eyes without (SD 0.18; range 0.5-1.0). Four of 5 eyes with macular edema had a postoperative visual acuity of 0.5 or better. There was no evidence of persistent IOP elevation or IOL decentration. No serious complications were recorded during surgery. CONCLUSIONS: Transscleral fixation of posterior chamber IOLs provides adequate visual acuity in most patients. Macular edema was frequently associated with the procedure. Although this complication was a cause of low visual recovery after implantation, the majority of eyes with macular edema achieved a visual acuity of 0.5 or better. Light-induced retinal injury was a permanent complication.

Aged↗
PubMed1997

Long-term liver cell cultures in bioreactors and possible application for liver support.

Hybrid artificial liver systems are being developed as a temporary extracorporeal liver support therapy. A short overview is given which emphasizes the development of hepatocyte culture models for bioreactors, subsequent in vitro studies, animal studies and the clinical application of hybrid liver support systems. An own bioreactor construction has been designed for the utilization of hepatocytes and sinusoidal endothelial cells. The reactor is based on capillaries for hepatocyte aggregate immobilization, coated with biomatrix. Four separate capillary membrane systems, each permitting a different function, are woven in order to create a three-dimensional network. Cells are perfused via independent capillary membrane compartments. Decentralized oxygen supply and carbon dioxide removal with low gradients is possible. There is a decentralized co-culture compartment for nonparenchymal liver cells. The use of identical parallel units to supply a few hepatocytes facilitates scale-up.

Animals↗
PubMed2002

Some recovery processes in mutual-help groups for persons with mental illness; I: qualitative analysis of program materials and testimonies.

Outcome research is beginning to suggest that mutual-help programs lead to significant improvements in the quality of life and related factors of members who have serious mental illness. This paper is the first in a series that examines recovery processes that may account for these positive outcomes. In Study 1, a content analysis was completed on one dimension of the written program for GROW, a mutual-help program with more than 40 years of experience. Thirteen reliable recovery processes emerged from this analysis; most prominent among these was to "be reasonable" and to "decentralize from self by participating in community." In Study 2, the recovery processes that emerged from this analysis of one aspect of GROW's written program were applied to 22 written testimonies made by Growers. Results of this analysis again showed being reasonable and decentralizing from self by participating in community were essential processes in this mutual-help program. Analysis of the personal testimonies also showed accepting one's personal value as an important element in the GROW program.

Community Mental Health Services↗
PubMed2004

Altruism, altruistic punishment and social investment.

The concept of altruism is used in very different forms by computer scientists,economists, philosophers, social scientists, psychologists and biologists. Yet, in order to be useful in social simulations, the concept "altruism" requires a more precise meaning. A quantitative formulation is proposed here, based on the cost/benefit analysis of the altruist and of society at large. This formulation is applied in the analysis of the social dynamic working of behaviors that have been called "altruistic punishments", using the agent based computer model Sociodynamica. The simulations suggest that "altruistic punishment" on its own cannot maintain altruistic behaviors. "Altruistic behavior" is sustainable in the long term only if these behaviors trigger synergetic forces in society that eventually make them produce benefits to most individuals. The simulations suggest however that "altruistic punishment" may work as a "social investment", and is thus better called "decentralized social punishment". This behavior is very efficient in enforcing social norms. The efficiency of decentralized social punishment in enforcing norms was dependent on the type of labor structured of the virtual society. I conclude that what is called "altruistic punishment" emerges as a type of social investment that can evolve either through individual and/or group selection, as a successful device for changing or enforcing norms in a society. Social simulations will help us in better understanding the underlying dynamic working of such devices.

Altruism↗
PubMed2004

Recovery of mechanoreception at the initial stage of regeneration of injured sciatic nerve in rats in conditions of central axotomy of sensory neurons.

The ability of injured afferents of the rat sciatic nerve to regenerate in conditions of damage to their connections with the central nervous system (CNS) as a result of extensive rhizotomy was studied. Recording of spike activity from single nerve fibers demonstrated that rhizotomy, performed simultaneously with nerve injury, had virtually no effect on the initiation of regenerative processes in sensory nerve fibers. The first clear signs of reinnervation of the skin of the foot by decentralized nerve fibers was seen 30 days after nerve injury, which agrees with data obtained in standard conditions, i.e., without rhizotomy. Decentralization of sensory neurons was found to lead to increases in the threshold of perception of a mechanical stimulus in intact and regenerating receptors. However, regenerating receptors showed a significantly more marked decrease in stimulus sensitivity.

Animals↗
PubMed2004

Cataract surgery after intravitreal injection of triamcinolone acetonide.

PURPOSE: To report the clinical outcome of patients undergoing cataract surgery after one or repeated intravitreal injections of triamcinolone acetonide as treatment of intraocular neovascular or oedematous diseases. METHODS: The interventional clinical case series study included all patients (n=22) who presented with cataract which had progressed after a single or repeated intravitreal injection of 25 mg of triamcinolone acetonide as treatment of exudative age-related macular degeneration (n=18) or diffuse diabetic macular oedema (n=4). Duration of the follow-up period was 3.76+/-4.99 months. With topical anaesthesia, the patients underwent standard cataract surgery including clear cornea incision, phakoemulsification and aspiration of the lens nucleus and cortex, and implantation of a foldable posterior chamber lens. The main outcome measures were frequencies of capsular rupture, vitreous loss, postoperative infectious endophthalmitis, secondary cataract, and decentration of the intraocular lens, visual acuity and intraocular pressure. RESULTS: Intraoperative dialysis of the lens zonules occurred in one (4.5%) eye and resulted in a loss of vitreous. Secondary cataract leading to Nd : YAG laser capsulotomy was observed in one (4.5%) eye. An optically significant decentration of the IOL or infectious endophthalmitis was not encountered in any patient. Visual acuity increased from 0.11+/-0.10 to 0.13+/-0.94 during the follow-up. Within 1 week after surgery, intraocular pressure was in the normal range in all the eyes. CONCLUSIONS: Cataract surgery after single or repeated intravitreal injection of 25 mg of triamcinolone acetonide does not harbour a markedly elevated frequency or a markedly changed profile of surgical complications.

Aged↗
PubMed2006

Comparison of two acrylic intraocular lenses with different haptic designs in patients with combined phacoemulsification and pars plana vitrectomy.

PURPOSE: The intra- and postoperative characteristics of two foldable single-piece intraocular lenses (IOL) with identical hydrophilic acrylic material, but different haptic designs (Akreos Adapt and Akreos Fit), were compared in combined phacoemulsification and pars plana vitrectomy (PPV). METHODS: This was a prospective, randomized study in patients with simultaneous cataract and vitreoretinal surgery. Group A (n=47 patients) included implantation of Akreos Fit IOL (two-point haptic) and group B (n=46 patients) implantation of Akreos Adapt IOL (four-point haptic). All intraoperative modifications of small-incision phacoemulsification and three-port PPV and IOL implantation and centration were documented. At 1 and 2 days and 6 months after surgery, best-corrected visual acuity (BCVA), slit-lamp appearance (including inflammation, IOL centration, capsulorhexis diameter, posterior capsule opacification (PCO), tonometry, and fundus findings were evaluated. RESULTS: The groups did not differ with respect to age, surgical indications and modifications, intraoperative IOL handling, and centration. At day 2, inflammation and capsulorhexis diameters were similar, but IOL decentration was slightly more frequent with Akreos-Fit IOLs. Six months after surgery, the rates of PCO, posterior synechiae, and BCVA were similar. Akreos-Fit had slightly smaller capsulorhexis diameters and slightly more capsular contraction and IOL decentration (P>0.05). CONCLUSIONS: Both of the Akreos IOL are feasible for combined phacoemulsification and PPV. Although similar in intraoperative handling, BCVA, and PCO, IOL centration was slightly better with Akreos-Adapt than with Akreos-Fit after combined surgery.

Aged↗
PubMed2001

[Millenniums update on posterior capsule opacification (PCO) scores, centration, biocompatibility and fixation of foldable intraocular lenses (IOL) - an analysis of 1,221 pseudophakic post mortem globes].

BACKGROUND: The ongoing and fast evolution of foldable IOL designs established the necessity to evaluate the different abilities of each lens style. The large IOL database (over 16,500 specimens) acquired in our laboratory, has permitted us to perform a clinico-pathological analysis on pseudophakic autopsy globes provided from sources worldwide, especially many Lions Eye banks in the United States. MATERIAL AND METHODS: We analyzed 6 foldable IOL styles commonly implanted in the United States, using one type of rigid IOL design (1-piece design rigid PMMA optics) as a comparison group. Posterior capsule opacification (PCO) score, decentration, fixation, presence or absence of a Nd:YAG laser posterior capsulotomy and area and intensity of Soemmerring's ring formation was discerned by examination under an operating microscope using the Miyake-Apple posterior photographic technique. RESULTS: The four lenses with the lowest rates ranging between 3.8 % and 21.7 % are modern designs, mostly implanted after 1992. The two lenses with the higher rates ranging between 23.1 % and 30.4 %, were all older designs, already prevalent prior to 1992. IOL fixation with both haptics in the capsular bag showed the best centration values and PCO scores. Our studies to date have shown in a preliminary fashion that the AcrySoftrade mark IOL displays the the lowest (best) biocompatibility score. CONCLUSIONS: Entering the new millenium, with evolution of modern surgical techniques and IOL designs, the incidence of the two major complications of cataract surgery, decentration and PCO are now finally diminishing.

Autopsy↗