Frequency and Distribution of Ophthalmic Surgical Procedures among Patients with Inherited Retinal Diseases

OBJECTIVE

In this study, we aimed to characterize the frequency and distribution of ocular surgeries in patients with inherited retinal diseases (IRDs) and evaluate associated patient and disease factors.

DESIGN

Retrospective cohort.

PARTICIPANTS

Subjects aged ≥ 18 years who were followed at the Johns Hopkins Genetic Eye Disease Center.

METHODS

We studied a retrospective cohort of patients with an IRD diagnosis to analyze the occurrence of laser and incisional surgeries. Subjects were categorized into 2 groups: central dysfunction (macular/cone/cone-rod dystrophy, "MCCRD group") and panretinal or peripheral dysfunction (retinitis pigmentosa-like, "RP group"). Genetic testing status was recorded. The association of patient and disease factors on the frequency, distribution, and timing of surgeries was analyzed.

MAIN OUTCOME MEASURES

Prevalence, prevalence odds ratio (POR), hazard ratio (HR) of ophthalmic procedures by phenotype.

RESULTS

A total of 1472 eyes of 736 subjects were evaluated. Among them, 31.3% (n = 230) had undergone ocular surgery, and 78.3% of those (n = 180/230) had a history of more than 1 surgery. A total of 602 surgical procedures were analyzed. Cataract extraction with intraocular lens implantation (CEIOL) was the most common (51.2%), followed by yttrium aluminum garnet capsulotomy, refractive surgery, retinal surgery, and others. Cataract extraction with intraocular lens implantation occurred more frequently in RP than in MCCRD subjects (POR, 2.59; P = 0.002). Retinitis pigmentosa subjects underwent CEIOL at a younger age than patients with MCCRD (HR, 2.11; P < 0.001).

CONCLUSIONS

Approximately one-third of patients with IRD had a history of laser or incisional surgery. Cataract extraction with intraocular lens implantation was the most common surgery; its frequency and timing may be associated with the IRD phenotype. This data may inform the design of prospective research. Such efforts may illuminate routine clinical decision-making and contribute to surgical strategy development for cell and gene therapy delivery.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Faster emergence behavior from ketamine/xylazine anesthesia with atipamezole versus yohimbine

Recent interest in reversal of the hypnotic effects of anesthesia has mainly focused on overcoming a surge in GABA-mediated inhibitory signaling through activation of subcortical arousal circuits or antagonizing GABA receptors. Here we examine the reversal of anesthesia produced from non-GABA agents ketamine/xylazine and the effects of antagonists of adrenoreceptors. These antagonists vary in selectivity and produce temporally unique waking behavior post-anesthesia. We compared two antagonists with differential selectivity for α₁- vs. α₂-receptors, yohimbine (YOH, 1:40 selectivity) and atipamezole (ATI, 1:8500). Adult mice received intraperitoneal injections of either YOH (4.3 mg/kg), ATI (0.4 mg/kg), or saline after achieving sustained loss of righting following injection of ketamine/xylazine (ketamine: 65.0 mg/kg; xylazine: 9.9 mg/kg). Behaviors indicative of the post-anesthesia, re-animation sequence were carefully monitored and the timing of each behavior relative to anesthesia induction was compared. Both YOH and ATI hastened behaviors indicative of emergence, but ATI was faster than YOH to produce certain behaviors, including whisker movement (YOH: 21.9±1.5 min, ATI: 17.5±0.5 min, p = 0.004) and return of righting reflex (RORR) (YOH: 40.6±8.8 min, ATI: 26.0±1.2 min, p<0.001). Interestingly, although YOH administration hastened early behavioral markers of emergence relative to saline (whisking), the completion of the emergence sequence (time from first marker to appearance of RORR) was delayed with YOH. We attribute this effect to antagonism of α₁ receptors by yohimbine. Also notable was the failure of either antagonist to hasten the re-establishment of coordinated motor behavior (e.g., attempts to remove adhesive tape on the forepaw placed during anesthesia) relative to the end of emergence (RORR). In total, our work suggests that in addition to pharmacokinetic effects, re-establishment of normal waking behaviors after anesthesia involves neuronal circuits dependent on time and/or activity.

Dopamine Deficiency Mediates Early Rod-Driven Inner Retinal Dysfunction in Diabetic Mice

Purpose

Electroretinograms (ERGs) are abnormal in diabetic retinas before the appearance of vascular lesions, providing a possible biomarker for diabetic vision loss. Previously, we reported that decreased retinal dopamine (DA) levels in diabetic rodents contributed to early visual and retinal dysfunction. In the current study, we examined whether oscillatory potentials (OPs) could serve as a potential marker for detecting early inner retinal dysfunction due to retinal DA deficiency.

Methods

Retinal function was tested with dark-adapted ERGs, taken at 3, 4, and 5 weeks after diabetes induction with streptozotocin. Electrical responses were analyzed and correlations were made with previously reported retinal DA levels. The effect of restoring systemic DA levels or removing DA from the retina in diabetic mice on OPs was assessed using L-3,4-dihydroxyphenylalanine (L-DOPA) treatments and retina-specific tyrosine hydroxylase (Th) knockout mice (rTHKO), respectively.

Results

Diabetic animals had significantly delayed OPs compared to control animals in response to dim, but not bright, flash stimuli. L-DOPA treatment preserved OP implicit time in diabetic mice. Diabetic rTHKO mice had further delayed OPs compared to diabetic mice with normal retinal Th, with L-DOPA treatment also providing benefit. Decreasing retinal DA levels significantly correlated with increasing OP delays mediated by rod pathways.

Conclusions

Our data suggest that inner retinal dysfunction in early-stage diabetes is mediated by rod-pathway deficits and DA deficiencies. OP delays may be used to determine the earliest functional deficits in diabetic retinopathy and to establish an early treatment window for DA therapies that may prevent progressive vision loss.

Scattering of laser pulses (plane wave and focused gaussian beam) by spheres

The scattering of laser pulses (in the femtosecond-picosecond range) by large spheres is investigated. We call a sphere large when its diameter is larger than the length associated with the pulse duration, allowing one to observe the temporal separation of scattering modes including surface waves.

Localized approximation for gaussian beams in elliptical cylinder coordinates

We establish a localized approximation to evaluate the beam-shape coefficients of a Gaussian beam in elliptical cylinder coordinates. As for the case of spherical coordinates and of circular cylinder coordinates, this approximation provides an efficient way to speed up computations within the framework of a generalized Lorenz-Mie theory for elliptical cylinders.

74As-arsenate metabolism in Flemish Giant rabbits with renal insufficiency

The metabolic management of carrier-free 74As-arsenate (As(V)) by uremic rabbits of the strain Flemish Giant was studied. Renal insufficiency was induced by nephrectomy of respectively 1 kidney (3/6 nephrectomy) and 1 kidney + 2/3 remaining kidney (5/6 nephrectomy). Marginal renal insufficiency developed in the 3/6 nephrectomized group, while animals of the 5/6 group became severely uremic. Renal excretion of 74As was reduced by 90% in 5/6 nephrectomized animals 4 h after intraperitoneal injection (i.p.) of the animals. The associated uremic syndrome caused a strong decrease in methylation capacity of inorganic arsenic (Asi). The second methylation step from monomethylarsonic acid (MMA) to dimethylarsinic acid (DMA) was more strongly affected than the first one, from arsenite (As(III)) to MMA. The increased availability of Asi led to more extensive binding to insoluble tissue constituents after 5/6 nephrectomy. The decreased renal reduction of As(V) led to a decrease in As(III) and an increase of As(V) and the associated As(V)-transferrin binding in plasma. Uptake of 74As-transferrin by the bone marrow might contribute to uremic anemia.

Cylindrical localized approximation to speed up computations for Gaussian beams in the generalized Lorenz-Mie theory for cylinders, with arbitrary location and orientation of the scatterer

A cylindrical localized approximation to speed up numerical computations in generalized Lorenz-Mie theory for cylinders, in a special case of perpendicular illumination, was recently introduced and rigorously justified. We generalize this approximation to the case when the cylinder is arbitrarily located and arbitrarily oriented in a Gaussian beam.

Scattering of a gaussian beam by an infinite cylinder with arbitrary location and arbitrary orientation: numerical results

We present numerical results concerning the properties of the electromagnetic field scattered by an infinite circular cylinder illuminated by a circular Gaussian beam. The cylinder is arbitrarily located and arbitrarily oriented with respect to the illuminating Gaussian beam. Numerical evaluations are provided within the framework of a rigorous electromagnetic theory, the generalized Lorenz-Mie theory, for infinite cylinders. This theory provides new insights that could not be obtained from older formulations, i.e., geometrical optics and plane-wave scattering. In particular, some emphasis is laid on the waveguiding effect and on the rainbow phenomenon whose fine structure is hardly predictable by use of geometrical optics.

Speciation measurements by HPLC-HGAAS of dimethylarsinic acid and arsenobetaine in three candidate lyophilized urine reference materials

Speciation measurements of dimethylarsinic acid (DMA) and arsenobetaine (AsB) in three candidate lyophilized urine reference materials are described. The measurements were based on cation-exchange liquid chromatography coupled to hydride generation atomic absorption spectrometry with on-line digestion of the organic. As species by alkaline persulfate solution aided by ultraviolet radiation. Arsenic concentrations as DMA were significantly different in the three samples. The mean values for the three samples were 4.1 +/- 0.3, 55.3 +/- 1.2 and 134.1 +/- 1.5 micrograms l-1, respectively. No significant differences in AsB concentrations were observed among the three samples. The mean As concentrations as AsB in the three samples were 17.4 +/- 0.4, 17.7 +/- 0.2 and 17.5 +/- 0.3 micrograms l-1, respectively. By off-line digestion of the urine samples, total As concentrations in the three materials were also obtained. The mean values were 23.4 +/- 0.3, 76.6 +/- 1.6 and 151.3 +/- 1.8 micrograms l-1, respectively. These results correlated well with the results obtained by neutron activation analysis in our laboratory (r = 0.999; p < 0.0001).

Chemical speciation of arsenic in serum of uraemic patients

Chemical speciation of arsenic was carried out in serum of a total of 51 uraemic patients: 19 non-dialysis (ND), 18 haemodialysis (HD) and 14 continuous ambulatory peritoneal dialysis (CAPD) patients. The low molecular mass As species were separated by ion-exchange liquid chromatography and measured on-line by hydride generation atomic absorption spectrometry (HGAAS). The high molecular mass As species were separated by fast protein liquid chromatography, either size-exclusion, ion-exchange or affinity chromatography, and the fractions were digested and measured off-line with HGAAS. The mean total As concentrations in the serum of the three groups of the uraemic patients were significantly higher than the reference value (6.47 +/- 4.28, 5.12 +/- 5.58 and 4.67 +/- 5.41 micrograms l-1 for HD, ND and CAPD patients, respectively, versus the reference value of 0.96 +/- 1.52 micrograms l-1. The major As species in serum of the patients were dimethylarsinic acid (DMA) and arsenobetaine. The HD patients showed a significantly higher mean DMA level than ND and CAPD patients. No selective removal of different As species in serum of HD patients was observed after 4 h of haemodialysis. The inorganic As species in serum were bound to proteins, mainly transferrin (about 5-6% of total As in serum). This binding may play an important role in arsenic detoxification.

Study of arsenic-protein binding in serum of patients on continuous ambulatory peritoneal dialysis

Arsenic (As) bound to serum proteins in patients on continuous ambulatory peritoneal dialysis (CAPD) was studied. A prior experiment by ultrafiltration showed that 5.57% of total As was bound to serum proteins for 14 CAPD patients. Further identification of the As species and protein molecules in serum of three CAPD patients with high As concentrations was carried out by combining the separation methods of size-exclusion, anion-exchange, and affinity fast-protein liquid chromatography, detected by hydride generation atomic absorption spectrometry. The results indicated that only inorganic As species are bound to serum proteins. Transferrin is the main carrier. The concentrations of As bound to proteins in serum for the three patients were 0.44 +/- 0.12, 0.19 +/- 0.09, and 0.59 +/- 0.09 microg/L (n = 3), respectively.

Basal metabolism of intraperitoneally injected carrier-free 74As-labeled arsenate in rabbits

The time-dependent occurrence of [74As]arsenate metabolites in Flemish Giant rabbits was investigated. As absorbed rapidly, reaching maximal concentrations in plasma and packed cells after 30 min and 2 hr, respectively. The [74As]arsenate in plasma and packed cells was reduced to [74As]arsenite, to 35 and 50% of the total 74As, respectively. The concentration of methylated As species in plasma and packed cells increased rapidly after 30 min. About 18% of total plasma 74As maximally bound to transferrin. Two-thirds of total 74As in packed cells bound to hemoglobin. Whereas little or no [74As]monomethylarsonic acid, one of the main As metabolites in humans, could be found in other animals, it is present in measurable amounts in the Flemish Giant. Furthermore, the plasma clearance rate of 74As species is lower than that in other rabbits and more similar to that of humans. The tissue 74As distribution varied widely with the highest concentrations in kidneys, liver, and lungs. 74As accumulated in bone whereas other tissues and blood showed rapid clearance rates. In muscle and heart an important part of arsenic was associated with components insoluble in phosphate-buffered isotonic saline. Binding of arsenic to soluble tissue proteins was most important in the kidneys, liver, and spleen. [74As]Arsenate metabolites were detected in all tissues. The relative amounts of [74As]arsenite or [74As]monomethylarsonic acid seldom exceeded 15% of total tissue 74As. The proportion of [74As]dimethylarsenic acid in the low molecular 74As fraction increased steadily. Substantial amounts of [74As]monomethylarsonic acid were found in the tissues..

Accumulation of arsenic species in serum of patients with chronic renal disease

Speciation of arsenic was determined in serum of 19 non-hemodialysis (non-HD) and 18 HD patients. The respective mean values of serum creatinine in these groups were 410 +/- 250 and 914 +/- 173 mumol/L (reference range for healthy subjects: females 50-80; males 57-93 mumol/L). The mean total arsenic concentrations were 5.12 +/-5.58 and 6.47 +/- 4.28 micrograms/L, respectively (reference value: 0.958 +/-1.52 micrograms/L). Dimethylarsinic acid (DMA) and arsenobetaine (AsB) were the major As species in serum of the non-HD and HD patients, with mean values of 0.82 +/- 1.05 and 1.93 +/- 1.51 micrograms/L for DMA and 3.55 +/- 4.58 and 3.47 +/- 2.89 micrograms/L for AsB, respectively. Serum concentrations of inorganic As and monomethylarsonic acid in both groups were below the detection limits for these compounds. Measurement of As concentration before vs after 4 h of HD treatment indicated that 68% of total As in serum was removed, as was 16% of the total As in packed cells. The efficiency of DMA and AsB removal during dialysis corresponded to that of total As.

Accumulation of arsenic species in serum of patients with chronic renal disease

Speciation of arsenic was determined in serum of 19 non-hemodialysis (non-HD) and 18 HD patients. The respective mean values of serum creatinine in these groups were 410 +/- 250 and 914 +/- 173 mumol/L (reference range for healthy subjects: females 50-80; males 57-93 mumol/L). The mean total arsenic concentrations were 5.12 +/-5.58 and 6.47 +/- 4.28 micrograms/L, respectively (reference value: 0.958 +/-1.52 micrograms/L). Dimethylarsinic acid (DMA) and arsenobetaine (AsB) were the major As species in serum of the non-HD and HD patients, with mean values of 0.82 +/- 1.05 and 1.93 +/- 1.51 micrograms/L for DMA and 3.55 +/- 4.58 and 3.47 +/- 2.89 micrograms/L for AsB, respectively. Serum concentrations of inorganic As and monomethylarsonic acid in both groups were below the detection limits for these compounds. Measurement of As concentration before vs after 4 h of HD treatment indicated that 68% of total As in serum was removed, as was 16% of the total As in packed cells. The efficiency of DMA and AsB removal during dialysis corresponded to that of total As.

Br, Rb, Zn, Fe, Se and K in blood of colorectal patients by INAA and PIXE

A preliminary study was conducted on blood samples and blood fractions of 11 colorectal patients and 10 healthy subjects (controls) in Belgium, in order to determine the concentration of some vital trace elements. Two non destructive analytical methods were used for the determination: INAA and PIXE. The agreement between PIXE and INAA was within about +/- 10% for plasma, but for Rb, Se and Fe in whole blood and red cells a difference of +/- 20% was noted; part of the discrepancy may be due to self absorption problems in PIXE, and for Rb, spectral interferences also may have contributed. The precision of the INAA method for the elements studied was found to be +/- 3% for whole blood and red cells and +/- 5% for plasma; the accuracy for Br, Rb and Zn was better than +/- 10% and +/- 17% for Se. The ratios of the concentrations in whole blood to red cells and whole blood to plasma were not significantly different for normals and cancer cases and, therefore, in future studies analysis of whole blood only may be sufficient. The mean values for Br, Rb, Br/Rb ratio, K, Fe and Se were significantly lower for cancer cases than for healthy individuals, and this might be applicable as an additional parameter for differentiating normals from malignant cases.

Determination of total arsenic in serum and packed cellsof patients with renal insufficiency

In order to investigate the arsenic level in serum and packed cells of patients with renal insufficiency, total arsenic (As) concentrations were determined with hydride generation atomic absorption spectrometry (HGAAS) in serum (S) and packed cells (PC) of 31 non-dialyzed patients. The accuracy of the method was tested by the analysis of arsenic in 3 certified reference materials. Patients showed a three-fold increase of arsenic concentrations in serum and a two-fold increase of arsenic in packed cells compared with controls. Patients (n=10) with higher serum creatinine (>2.0 mg/dL), urea (>0.70 g/L) and urinary protein (mean+/-SD: 1.12+/-0.82 g/L) showed higher arsenic concentrations (5.8+/-3.3 microg/L in serum and 18.0+/-16.7 microg/kg in packed cells) compared with those with lower creatinine (<1.6 mg/dL), urea (<0.6 g/L) and urinary protein (mean+/-SD: 0.27+/-0.82 g/L) (n=16, serum arsenic 1.2+/-1.2 microg/L, packed cells arsenic 2.6+/-1.9 microg/kg). The significant differences (both p < 0.001) in S and PC-arsenic levels of patients in group I and II implies a relationship between the arsenic level and the degree of chronic renal insufficiency.

More than tenfold increase of arsenic in serum and packed cells of chronic hemodialysis patients

Arsenic concentrations were determined in serum and packed cells of 7 chronic hemodialysis patients, in fresh dialysate and in a heparin solution. The analytical technique was radiochemical neutron activation analysis. The accuracy of the method was tested by the analysis of As in certified reference materials. Patients showed elevated serum and packed cell arsenic concentrations compared with controls (serum, range: 2.3-79.8 ng As/ml, median: 11.5 ng As/ml; versus range: 0.132-4.783 ng As/ml, median: 0.38 ng As/ml; packed cells, range: 2.1-68.4 ng As/g, median: 9.5 ng As/g; versus range: 0.51-14.44 ng As/g, median: 3.17 ng As/g). Arsenic concentrations remained unaltered, before versus after a single hemodialysis treatment. The arsenic contents of serum and packed cells were significantly correlated (n = 7, r = 0.96, p < 0.05). No arsenic could be detected in the heparin solution or in the dialysate.

The effect of adding Br or Zn supplements to the dialysate on the concentrations of Br and Zn in the blood of hemodialysed patients

The effect of adding Br or Zn supplementation to the dialysate on the concentrations of Br and Zn in the blood of hemodialysed patients, is investigated. Patients with end-stage renal failure on hemodialysis show an abnormal trace element pattern. Our patients showed lowered serum Br and Zn concentrations. Four patients were subjected to dialysates with varying Br content. The impact on their serum and packed cells concentrations was evaluated. The supplementation resulted in an increase in the concentrations in serum and in packed cells. The Br concentration in serum and packed cells closely followed the dialysate content. In order to restore the Zn concentration to the normal level a ZnCl2 solution was added to the dialysate of 4 other patients. Zn accumulated in the patient as a consequence of its diffusion against the concentration gradient.

Trace elements in serum, packed cells, and dialysate of CAPD patients

Neutron Activation Analysis (NAA) was used to investigate trace element patterns in serum, packed cells, and dialysate of CAPD patients. The concentrations of the elements Cs, Cu, Fe, and Mn in serum and packed cells appeared to be maintained within the normal range, while the levels of the non-essential element Br in both serum and packed cells were subnormal. The serum Cr values were extremely high (20 to 50 times higher than the normal serum level). The amount of Cr absorbed from the dialysate was calculated to be ten times higher than the daily dietary uptake. The Co concentrations were normal in packed cells but were significantly increased in serum. The Rb content in packed cells was slightly lower than normal, while the serum value was normal. Se was maintained within the normal range in packed cells, but the serum concentration was slightly lower than normal. The concentrations of Zn were low in serum and appeared to be higher than normal in packed cells. In conclusion, this analysis of the trace element status of CAPD patients reveals two major abnormalities. There is an apparent loss of Br from the blood towards the dialysate and on the other hand, a dramatic accumulation of Cr into the blood as a result of the very high Cr content in the dialysate.