The SKILL Card test in optic neuritis: experience of the Optic Neuritis Treatment Trial. Smith-Kettlewell Institute Low Luminance. Optic Neuritis Study Group.

OBJECTIVES: To assess the value of the Smith-Kettlewell Institute Low Luminance (SKILL) Card test, designed to measure vision at reduced contrast and luminance, among patients with previous optic neuritis. MATERIALS AND METHODS: The SKILL Card test was administered to 295 patients participating in the Optic Neuritis Treatment Trial (ONTT) follow-up study, concurrent with measurement of visual acuity, visual field, contrast sensitivity, and color vision. Health-related quality of life (HRQL) was also assessed in a subset of patients using the National Eye Institute Visual Function Questionnaire and an ONTT-developed questionnaire. RESULTS: The SKILL Card difference score (high-contrast acuity score minus low-contrast acuity score) was only weakly associated with the other measures of vision function (rs absolute range, 0.05-0.31) and with the HRQL measures (rs absolute range, 0.02-0.15). In contrast, the light and dark component scores of the SKILL Card test had higher associations with the other vision measures (rs absolute range, 0.27-0.54) and with the HRQL measures (rs absolute range, 0.10-0.40). CONCLUSIONS: The SKILL Card difference score is not a meaningful measure for patients with optic neuritis; however, the test appears to have clinical usefulness as a method to measure high-contrast and low-contrast acuity.

Acquired and progressive retinal nerve fiber layer myelination in an adolescent.

PURPOSE: To report the onset and progression of retinal nerve fiber layer myelination in an adolescent patient. METHODS: Case report. RESULTS: A 7-year-old male was found to have myelination of the retinal nerve fiber layer in the left eye. When he was reexamined at age 14 years, he was found to have new myelination in the right eye, progression of the myelination in the left eye, and bilateral optic nerve drusen. CONCLUSION: Retinal nerve fiber layer myelination can occur spontaneously in adolescence, progress in adolescence, and be associated with optic nerve drusen.

Selective loss of the electroretinogram B-wave in a patient with Creutzfeldt-Jakob disease.

Creutzfeldt-Jakob disease (CJD) is a neurodegenerative disease characterized by movement abnormalities and dementia that inevitably progress to death. Familial, infectious, and sporadic forms of the disease are recognized. The worldwide incidence of CJD is estimated at 1:1,000,000 per year, and it affects middle-aged men and women in roughly equal proportions. The disease is caused by a unique infectious vector, the prion, which is a mutant form of a normally occurring cell surface protein found predominantly in the central nervous system. A significant proportion of patients with CJD will have visual disturbances at some point in their illness and may therefore consult a neuro-ophthalmologist. The case of a woman in whom the diagnosis of CJD was not known until autopsy is reported. Early in the course of her disease, she sought ophthalmic consultation because of vision problems.

Ophthalmic manifestations of fibrous dysplasia: a disease of children and adults.

OBJECTIVE: To determine whether adults constitute a significant proportion of patients presenting with ophthalmic complications of fibrous dysplasia. DESIGN: A retrospective case series. PARTICIPANTS: Twenty patients with biopsy-proven fibrous dysplasia participated. MAIN OUTCOME MEASURES: Patient demographics, major signs and symptoms, occurrence of visual loss, pattern of bone involvement, and radiographic appearance of fibrous dysplasia were studied. RESULTS: In contrast to observations made in the past, the authors found that adults constitute a significant proportion of patients suffering from the ophthalmic complications of fibrous dysplasia. Of 20 patients, 9 were younger than 18 years of age (children) and 11 were 18 years of age or older (adults) at the time of presentation. Changes in facial contour and symmetry were the most common presenting signs and symptoms. Five patients, four of whom were adults, presented because of acute visual loss. Most patients had monostotic lesions that crossed suture lines to involve multiple craniofacial bones. On computed tomographic scan, most fibrous dysplasia lesions had a characteristic, pagetoid appearance, with alternating areas of radiolucency and radiodensity. CONCLUSIONS: Because fibrous dysplasia of the orbital bones can be a cause of significant dysfunction and disfigurement, as well as a treatable cause of blindness in both children and adults, the diagnosis of fibrous dysplasia should not be ruled out based solely on the age of the patient. The characteristic radiologic appearance of this disease allows one to differentiate fibrous dysplasia from other tumors associated with bony expansion or density changes, specifically meningioma.

Unexplained hypertension during induction of a patient with phaeochromocytoma.

An unexplained hypertensive response during the induction of anaesthesia for phaeochromocytoma resection is described. This response was not accompanied by elevations in plasma catecholamine levels. It occurred despite heavy premedication and followed induction with etomidate, alfentanil, lignocaine, vecuronium and magnesium sulphate (MgSO4). A bolus of esmolol (0.5 mg/kg) lowered the blood pressure rapidly. Subsequent haemodynamic manipulations were carried out by varying the rate of an esmolol infusion. A constant background infusion of MgSO4 was maintained throughout the procedure. These produced satisfactory haemodynamic control despite marked rises in plasma catecholamine levels.

Spatial buffering of extracellular potassium by Müller (glial) cells in the toad retina.

We examined the role of Müller (glial) cells in buffering light-evoked changes in extracellular K+ concentration, [K+]o, in the isolated retina of the toad, Bufo marinus. We found evidence for two opposing Müller cell current loops that are generated by a light-evoked increase in [K+]o in the inner plexiform layer. These current loops, which are involved in the generation of the M-wave of the electroretinogram (ERG), prevent the accumulation of K+ in the inner plexiform layer by transporting K+ both to vitreous and to distal retina. In addition, under dark-adapted conditions, we found evidence for a Müller cell current loop that is generated by a light-evoked decrease in [K+]o in the receptor layer. This current loop, which is involved in the generation of the slow PIII component of the ERG, helps to buffer the light-evoked decrease in [K+]o throughout distal retina by transporting K+ from vitreous. The spatial buffering fluxes of K+ can be abolished by blocking Müller cell K+ conductance with 200 microM Ba2+. The separate contributions of the M-wave and slow PIII currents to Müller cell spatial buffering were isolated by various pharmacological treatments that were designed to enhance or suppress light-evoked activity in specific retinal neurons. Our results show that Müller cell K+ currents not only buffer light-evoked increases in [K+]o, but also buffer light-evoked decreases in [K+]o, and thereby diminish any deleterious effects upon neuronal function that could arise in response to large changes in [K+]o in the plexiform layers. Moreover, our results emphasize that spatial buffering currents generate many components of the electroretinogram.

PII component of the toad electroretinogram.

1. The PII component of the electroretinogram (ERG) is comprised of the b-wave and the DC component and is thought to reflect bipolar cell activity. Although the b-wave is generated in large part by a K+/Müller cell mechanism, the origin of the DC component is unclear. In this paper we detail our investigation of the origin of the DC component. We hypothesize that the DC component is generated by a K+/Müller cell mechanism identical to that involved in b-wave generation. 2. We studied the ERG in the dark-adapted, isolated retina preparation of the toad, Bu fo marinus. We used K+ ion-sensitive microelectrodes (K+ISM), as well as conventional intra- and extracellular microelectrodes, to record [K+]o changes, the vitreal ERG, and Müller cell responses. 3. We used the excitatory amino acid receptor agonist N-methyl-DL-aspartate (NMDLA) to inhibit light responses of third-order neurons and thereby eliminate most of the ERG M-wave. In the absence of the M-wave, the ERG consisted of PII and PIII. We then superfused the retina with a solution containing both kynurenic acid (KYN) and 2-amino-4-phosphonobutyric acid (APB), which together inhibit all retinal responses proximal to the photoreceptors. In the presence of KYN and APB, the ERG consisted only of PIII. Using digital subtraction, we reconstructed PII. To our knowledge, this is the first report of the isolation of a PII component in the ERG of a nonmammalian species. 4. Using K+ISMs, we recorded the distal K+ changes in the outer plexiform layer (OPL).(ABSTRACT TRUNCATED AT 250 WORDS)

Speech and hearing problems in a high-risk population.

A retrospective study was conducted on 85 neonatal intensive care unit (NICU) survivors, all of whom had been mechanically ventilated. Mean birth weight was 1,726 +/- 778 g and mean gestational age was 32.3 +/- 3.8 weeks. Infants were evaluated for various risk factors previously reported to cause hearing loss. Language development was assessed using the Early Language Milestone (ELM) scale and hearing was tested by free field responses (FFR). Twenty-four children (28.2%) had an abnormal ELM or FFR result. Seventeen children failed an FFR; 14 of these were normal on follow-up and 3 defaulted. There was thus no permanent sensorineural hearing loss in the sample assessed. Eleven children failed an ELM, of whom 5 had speech problems on long-term follow-up. There was a significant correlation between the ELM and neurodevelopmental scores (P = 0.045). Intraventricular haemorrhage also correlated significantly with the ELM score (P = 0.0016). Thus the overall incidence of hearing loss in this NICU population was low, but there was a significant occurrence of speech problems, which correlated with neurological damage.

M-wave of the toad electroretinogram.

1. In the retina, two distinct, light-evoked releases of K+ have been described. One takes place in the outer plexiform layer (OPL) and is termed the "distal K+ increase." The other takes place in the inner plexiform layer (IPL) and is termed the "proximal K+ increase." Although the distal K+ increase generates the electroretinogram (ERG) b-wave, the contribution of the much larger proximal K+ increase to the ERG is less well understood. In this paper we detail our investigation of the proximal K+ increase and its contribution to the ERG. We describe an ERG component, the M-wave, which had not heretofore been observed in the diffuse-flash, vitreal ERG. 2. We studied the proximal K+ increase and the ERG M-wave in the isolated retina preparation of the toad, Bufo marinus. We used K(+)-sensitive microelectrodes, as well as conventional intra- and extracellular microelectrodes, to record K+ changes, the local (or intraretinal) ERG, the vitreal ERG, and Müller cell responses. 3. As in earlier studies of the amphibian and cat M-wave, we readily observed an M-wave in the intraretinal, or local, ERG (LERG). The M-wave we studied had characteristics similar to those of M-waves that were previously described. Specifically, we found that the M-wave was generated by a Müller cell response to the proximal K+ increase and that both the proximal K+ increase and the LERG M-wave were spatially tuned. 4. We used the aspartate receptor agonist, N-methyl-DL-aspartate (NMA), to reveal that an M-wave is present in the vitreal ERG. Researchers who previously investigated the M-wave were unable to identify an M-wave in the vitreal ERG. We found that the toad ERG M-wave was a small, positive potential that was partially obscured by the much larger b-wave and slow PIII components. 5. We observed that picrotoxin (PTX) had an excitatory effect on inner retina, as evidenced by an enhanced proximal K+ increase and an enhanced M-wave. This result indicates that it is likely that GABAergic inhibition in inner retina plays an important role in retinal processing in the toad. 6. At threshold, we found that the ERG consisted mainly of an M-wave, indicating that the amphibian threshold ERG is driven by proximal retina. This result is analogous to previous observations of the threshold ERG in cat. However, in cat, the M-wave and threshold response have been described as distinct ERG components.(ABSTRACT TRUNCATED AT 400 WORDS)

Evidence for Na+/H+ exchange in vertebrate rod photoreceptors.

In this paper, we have documented our investigation of pH regulation in the rod photoreceptor of the toad, Bufo marinus. Unlike other neural tissues, the retina depends upon aerobic glycolysis to meet its energy requirements. A consequence of its reliance on glycolysis is a large metabolic production of protons (H+) which must be extruded by pH regulating mechanisms. Based on the work of previous authors, we propose that rods share these same characteristics with whole retina. Our results in rods are consistent with the hypothesis that under nominally bicarbonate-free conditions, an amiloride-sensitive Na+/H+ exchanger contributes to pH regulation in this cell.

Effectiveness of community preventive programs on improving oral health.

Although sizable community efforts in the United States have been made to educate children and adults about periodontal disease and its control, valid inferences regarding their effectiveness cannot be made because, for the most part, invalid methods of evaluation have been used. Confusion about these methods may exist because there has been little conviction that the available methods of control will stop the progress of periodontal pathology. Many recommended oral hygiene practices are probably applicable only to certain motivated individuals. An effective, comprehensive community-program for the prevention of periodontal disease remains to be developed. It is unlikely that sufficient sums of money and personnel could be diverted from the budgets of lesser-developed countries to initiate mass oral hygiene programs. Therefore, it appears that, organized community efforts appear to be promising only for the control of dental caries. However, it must be remembered that community fluoridation may not be applicable in many countries. Therefore, new strategies and vehicles to bring fluorides to all segments of the world's population are needed.

Effect of immunization on acute and latent infections of vaginouterine tissue with herpes simplex virus types 1 and 2.

Inoculation of mice with herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) by the vaginal route resulted in viral shedding during the acute phase of the infection and the development of a latent infection in vaginouterine tissue lasting up to one year in greater than 25% of the animals. Immunization with either serotype of HSV markedly reduced viral shedding when animals were subsequently challenged with the homologous serotype, but immunization with HSV-2 was significantly less effective in preventing the development of a latent infection in the vaginouterine tissue after challenge than was immunization with HSV-1.