ABSTRACT
El uso de anestésicos locales para la realización de procedimientos odontológicos es una práctica ampliamente extendida que puede causar efectos adversos. Sin embargo, muy infrecuentemente puede causar complicaciones oculares como diplopía, ptosis, visión borrosa, miosis, disminución de la agudeza visual o amaurosis. Presentamos un caso de un paciente varón de 26 años que se presentó a la consulta por una disminución de la agudeza visual en su ojo derecho 48h después de una intervención odontológica del lado ipsilateral, logrando una recuperación de la misma en los 6 meses posteriores, sin tratamiento alguno. Diferentes teorías que justifiquen la aparición de complicaciones oculares como consecuencia de esta clase de procedimientos han sido propuestas en la literatura. En nuestro caso, una inyección intravenosa inadvertida habría sido la causa posible del hecho (AU)
The use of intra-oral local anaesthetics for dental procedures is a widely extended practice that may cause side effects. As such, in rare cases it may cause ocular complications such as diplopia, ptosis, blurry vision, miosis, vision loss, or amaurosis. (Most of them are transient, recovering after several hours or days). A case is presented of a 26 year-old male patient who had visual impairment in the right eye 2 days after a dental procedure was performed. Six months later he had a complete restoration of the previous visual acuity, despite the fact that he had not received any treatment. Several ways have been proposed in the literature that may explain the appearance of ocular complications following these kinds of procedures. In this case, inadvertent intravenous injection is believed to have been the cause (AU)
Subject(s)
Humans , Male , Adult , Anesthesia, Local/adverse effects , Anesthetics/adverse effects , Diplopia/etiology , Vision Disorders/etiology , Tooth Extraction/adverse effects , Visual Acuity/drug effectsABSTRACT
The use of intra-oral local anaesthetics for dental procedures is a widely extended practice that may cause side effects. As such, in rare cases it may cause ocular complications such as diplopia, ptosis, blurry vision, miosis, vision loss, or amaurosis. (Most of them are transient, recovering after several hours or days). A case is presented of a 26 year-old male patient who had visual impairment in the right eye 2 days after a dental procedure was performed. Six months later he had a complete restoration of the previous visual acuity, despite the fact that he had not received any treatment. Several ways have been proposed in the literature that may explain the appearance of ocular complications following these kinds of procedures. In this case, inadvertent intravenous injection is believed to have been the cause.
Subject(s)
Anesthesia, Local , Vision Disorders , Adult , Anesthetics, Local/adverse effects , Blindness , Diplopia/etiology , Humans , Male , Vision Disorders/etiologyABSTRACT
The use of intra-oral local anaesthetics for dental procedures is a widely extended practice that may cause side effects. As such, in rare cases it may cause ocular complications such as diplopia, ptosis, blurry vision, miosis, vision loss, or amaurosis. (Most of them are transient, recovering after several hours or days). A case is presented of a 26 year-old male patient who had visual impairment in the right eye 2 days after a dental procedure was performed. Six months later he had a complete restoration of the previous visual acuity, despite the fact that he had not received any treatment. Several ways have been proposed in the literature that may explain the appearance of ocular complications following these kinds of procedures. In this case, inadvertent intravenous injection is believed to have been the cause.
ABSTRACT
The degree of 1D character of surface chains at group IV (111)-2 × 1 reconstructed surfaces is established by surface sensitive optical spectroscopy. Optical experiments on a diamond C(111)-2 × 1 surface show that the absorption peak related to dangling-bond transitions exhibits a marked blueshift upon oxygen exposure of the clean surface. Such behaviour is analogous to that observed on a clean Si(111)-2 × 1 surface. For both surfaces the experimental finding is interpreted in terms of quantum confinement of surface electrons in quasi-one-dimensional π-bonded chains, whose length decreases with oxygen uptake. A different behaviour is observed in Ge(111)-2 × 1, where only a very slight blueshift of the surface-state optical transition is detected upon oxidation. The almost negligible blueshift in Ge(111)-2 × 1 is consistent with a significant coupling between the π-bonded chains resulting in a much less pronounced one-dimensional character of Ge(111)-2 × 1 surface electrons compared to diamond and silicon reconstructed surfaces.
ABSTRACT
Domains of different surface reconstruction-negatively or positively buckled isomers-have been previously observed on highly n-doped Si(111)-2 × 1 surfaces by angle-resolved ultraviolet photoemission spectroscopy and scanning tunneling microscopy/spectroscopy. At low temperature, separate domains of the two isomer types are apparent in the data. It was argued in the previous work that the negative isomers have a lower energy of their empty surface states than the positive isomers, providing a driving force for the formation of the negative isomers. In this work we show that the relative abundance of these two isomers shows considerable variation from sample to sample, and it is argued that the size of the isomer domains is likely to be related to this variation. A model is introduced in which the electrostatic effect of charge transfer between the domains is computed, yielding total energy differences between the two types of isomer. It is found that the transfer of electrons from domains of positive isomers to negative ones leads to an energetic stabilization of the negative isomers. The model predicts a dependence of the isomer populations on doping that is in agreement with most experimental results. Furthermore, it accounts, at least qualitatively, for the marked lineshape variation from sample to sample observed in photoemission spectra.
ABSTRACT
A long-standing puzzle regarding the Si(111) − 2 × 1 surface has been solved. The surface energy gap previously determined by photoemission on heavily n-doped crystals was not compatible with a strongly bound exciton known from other considerations to exist. New low-temperature angle-resolved photoemission and scanning tunneling microscopy data, together with theory, unambiguously reveal that isomers with opposite bucklings and different energy gaps coexist on such surfaces. The subtle energetics between the isomers, dependent on doping, leads to a reconciliation of all previous results.
ABSTRACT
PURPOSE: To determine the central corneal thickness after administration of the anti-glaucomatous medications latanoprost 0.005% or dorzolamide 2%, as assessed in rabbits which have had total corneal thickness autografts. METHODS: A bilateral total corneal thickness autograft was performed in ten rabbits. One rabbit was excluded from the subsequent study in which the antiglaucomatous medication was started two months post-operatively. Latanoprost 0.005% was instilled once per day into the right eye, whereas the left eyes were treated with dorzolamide 2% twice a day. The eyes were examined by biomicroscopy and ultrasound pachymetry immediately prior to commencement, and 4, 10, 17 and 27 weeks after starting the anti-glaucomatous treatment. In each instance three assessments of the central corneal thickness in each eye were made. At the end of the study, the influence of time and treatment on the corneal thickness was analyzed using a generalized linear model for repeated measurements. All penetrating keratoplasties were performed by the same surgeon (C.H.P). RESULTS: Treatment with dorzolamide resulted in corneal edema and a significant increase in central corneal thickness, whereas the treatment with latanoprost resulted in neither corneal edema nor corneal thickness changes. CONCLUSIONS: Dorzolamide, when instilled into the eyes of rabbits with corneal autografts, could have a negative effect on the graft, impairing the endothelial function through inhibition of the ionic pump. This effect could cause graft failure, which may be able to be defined with ultrasound pachimetry.
Subject(s)
Antihypertensive Agents/pharmacology , Cornea/drug effects , Cornea/pathology , Corneal Transplantation , Prostaglandins F, Synthetic/pharmacology , Sulfonamides/pharmacology , Thiophenes/pharmacology , Animals , Latanoprost , RabbitsABSTRACT
The problem of monitoring the structural and morphological evolutions of thin films of organic molecular materials during their growth by organic molecular beam epitaxy and in the postgrowth stage is addressed here by a combination of in situ optical reflectance anisotropy measurements, ex situ optical and morphological investigations, and theoretical simulation of the material optical response. For alpha-quaterthiophene, a representative material in the class of organic molecular semiconductors, the results show that molecules crystallize in the first stage of growth in metastable structures, even when deposition is carried out at room temperature. In the postdeposition stage, the film structure evolves within a few days to the known equilibrium structure of the low temperature polymorph. When deposition is carried out at low substrate temperatures, an evolution of the film morphology is also demonstrated.
ABSTRACT
A succinct analysis of normal-incidence reflectometers for surface anisotropy, based on the Jones-matrix formalism, is performed. In particular, two relevant configurations with and without analyzers are compared and discussed. The latter is found to be more user friendly than the former, since most errors vanish to the first order of approximation. Therefore the optical alignment is greatly simplified. On the other hand, this configuration does not yield complete physical information. We discuss how this drawback can be circumvented in surface studies by use of the three-layer model and a Kramers-Kronig analysis.
ABSTRACT
BACKGROUND: Anterior chamber miotic solutions are widely used in ophthalmic surgery to induce pupillary contraction. We investigated whether the acetylcholine, carbachol, or mannitol present in perfusing solutions can affect corneal endothelial function. METHODS: Freshly dissected deepithelized rabbit corneas were mounted in a Dikstein-Maurice chamber at 36 degrees C. The endothelial sides were perfused with six solutions: (A) 55 mM (1%) acetylcholine Cl plus modified balanced salts; (B) control for A, with acetylcholine Cl replaced by sucrose; (C) 0.55 mM (0.01%) carbachol Cl plus balanced salts; (D) balanced salts solution (BS; control for C); (E) 3% mannitol plus modified balanced salts; and (F) modified balanced salts (control for E, with mannitol replaced by sucrose). Corneal thickness was followed for 3 h in each experiment. The effect of solution E did not differ from that of solution F. RESULTS: The carbachol-containing solution produced a small increase in corneal thickness compared to the control solution, while the acetylcholine-containing solution resulted in corneal thickness lower than that in control preparations. CONCLUSION: From these data, acetylcholine is harmless to the endothelium, and may actually stimulate its fluid pump mechanism. Carbachol, on the other hand, appears to have a detrimental effect.
Subject(s)
Acetylcholine/pharmacology , Carbachol/pharmacology , Diuretics, Osmotic/pharmacology , Endothelium, Corneal/physiology , Mannitol/pharmacology , Miotics/pharmacology , Animals , Biological Transport, Active/drug effects , Endothelium, Corneal/cytology , Endothelium, Corneal/drug effects , In Vitro Techniques , Male , Perfusion , RabbitsABSTRACT
BACKGROUND: Anterior chamber miotic solutions are widely used during anterior chamber surgery. We examined the effects of solutions containing miotic agents such as carbachol and/or acetylcholine on corneal endothelial pumping activity. METHODS: We monitored, in vitro, the transendothelial electrical potential difference of isolated rabbit corneal endothelial preparations. As controls, we used solutions without miotics. RESULTS: We found that a solution containing 55 mM acetylcholine and minimal amounts of salts (Miochol E) maintains transendothelial electrical potential difference some 30% above control levels for up to 4 h. Two other solutions, one including balanced salts and 0.55 mM carbachol (Miostat), the other a mixture of 0.19 mM carbachol and 55 mM acetylcholine plus minimal salts, are adequate to maintain the potential difference at control levels. Lastly, a solution with acetylcholine but without any salts (Miochol) greatly decreases the potential difference, to 30% of the control level, in 100 min. CONCLUSION: Our results indicate that: (1) 55 mM (1%) acetylcholine stimulates the endothelial electrical potential difference; (2) addition of 0.19 mM (0.003%) carbachol negates the stimulatory effect of acetylcholine; and (3) absence of electrolytes severely depresses the endothelial electrical activity.
