Impaired retinal processing in regular cannabis users: Potential benefit of electroretinogram as a biomark

Cannabis is one of the most prevalent drugs used in industrialized countries. Regular cannabis use is associated with impairments in highly integrative cognitive functions such as memory, attention and executive functions. However, the neural impact of cannabis use remains poorly understood. Elucidating the cerebral mechanisms underlying these deficits represents now a crucial step in addictive disorders. The retina is a part of the central nervous system due to its embryonic origin thereby reflecting the neurochemistry of the brain. Furthermore its measure is well standardized allowing good reproducibility. Considering the anatomical and functional distribution of endocannabinoids in the retina [1], we evaluated the retinal function in regular cannabis users and healthy control subjects. Recordings of flash electroretinogram (fERG) were performed in regular cannabis users and healthy controls using guidelines of international society for clinical electrophysiology of vision (ISCEV) [2]. Both amplitude and implicit time of a-wave and b-wave were assessed in scotopic and photopic conditions. Measurements of fERG showed increased implicit time of a-wave and b-wave in both photopic and scotopic conditions in regular cannabis users compared to healthy controls. These findings suggest that retinal processing may be altered at the level of photoreceptor and bipolar cells in regular cannabis users. These results are consistent with previous reports in animal species, which show the involvement of the cannabinoid system in the regulation of the retinal metabolism thus leading to alterations of fERG measurements. Since alterations in the central neurotransmission may affect the ERG measurements, the retina might constitute a possible biomarker of brain disorders in addictive diseases [3].

[Recurrent unilateral optic neuropathy associated with human immunodeficiency virus (HIV)]

HIV-related optic neuropathy is rare compared to optic neuropathies secondary to opportunistic infections in seropositive patients. We report the case of a 39-year-old HIV-positive woman referred for unilateral visual loss leading to the diagnosis of recurrent, unilateral, inflammatory optic neuropathy directly associated with HIV. Despite initial recovery after steroid treatment, she relapsed twice. Absence of any opportunist infections or toxic causes and presence of a very high viral load due to non-compliance with treatment led to the diagnosis of HIV-related optic neuropathy. Steroids and effective anti-retroviral treatment resulted in definitive and complete recovery. Inflammatory, degenerative and/or vascular mechanisms have been hypothesized to explain the occurrence of these rare HIV-related optic neuropathies. This diagnosis remains a diagnosis of exclusion to be considered in the work-up of seropositive patients with optic neuropathies.

["Teddy bear granuloma", a rare condition: a case report of a 3-year-old child]

Conjunctival synthetic fiber granulomas, or "Teddy bear granulomas", are rare granulomatous responses to synthetic fabric fibers. We report the case of a 3-year-old boy with no prior infectious or traumatic history, brought in by his parents for an incidentally discovered conjunctival growth in his right eye. Slit lamp examination revealed a 10-mm growth in the inferior fornix surrounding a small greyish foreign body. Surgical excision and histopathology revealed granulomatous inflammatory cell response with foreign body giant cells surrounding exogenous material. This foreign material was birefringent in polarized light, very suggestive of synthetic fabric fibers, which permitted the diagnosis of Teddy bear granuloma. Synthetic fiber granulomas present in children as unilateral, more or less inflammatory growths in the inferior conjunctival fornix. Surgical excision with histopathology makes the diagnosis and effects the cure.

[Wolfram syndrome: clinical and genetic analysis in two sisters]

Wolfram syndrome is a severe genetic disorder defined by the association of diabetes mellitus, optic atrophy, deafness, and diabetes insipidus. Two sisters complained of progressive visual loss. Fundus examination evidenced optic atrophy. Their past medical history revealed diabetes mellitus and deafness since childhood. The association of these symptoms made the diagnosis of Wolfram syndrome possible. It was confirmed by molecular analysis, which evidenced composite WFS1 heterozygous mutations inherited from both their mother and father. Ophthalmologists should be aware of the possibility of Wolfram syndrome when diagnosing optic atrophy in diabetic children.

Intravascular lymphoma mimicking a Vogt-Koyanagi-Harada disease

PURPOSE

To report a case of intravascular lymphoma (IVL) mimicking a Vogt-Koyanagi-Harada disease (VKH).

DESIGN

Case report.

METHODS

A 38-year-old man was referred for blurred vision, headache, and hearing loss. Examination demonstrated vitritis and subretinal detachments in each eye. Cerebral fluid analysis showed lymphocytic meningitis. Cerebral MRI was normal. A diagnosis of VKH disease was made.

RESULTS

Steroid treatment was introduced, after which all symptoms disappeared. Six months later, the patient returned with paraplegia and confusion. Cerebral MRI revealed hypodense periventricular lesions. A stereotaxic biopsy confirmed the diagnosis of IVL. The patient died a few months later.

CONCLUSION

IVL may have many revealing aspects, including ophthalmologic symptoms.

[A case report of frosted branch angiitis associated with aseptic meningitis in a young boy]

We report on an 11-year-old boy with frosted branch angiitis in both eyes associated with aseptic meningitis. The patient presented after a severe decrease in vision in both eyes and a 40°C fever. The examination of the fundus of the eyes revealed a diffuse edema of the retina and diffuse bilateral vascular sheathing. The complementary examinations revealed aseptic meningitis. Neither infectious etiologies nor systemic diseases could be confirmed and an inflammatory digestive disease was suspected because of recent diarrhea events responsible for substantial weight loss. A systemic corticotherapy slowly improved the vision in both eyes. After 1 year of medication, visual recovery was full with no sequelae on fundus examination.

[Limbal-conjunctival autograft in pterygium surgery]

INTRODUCTION

The aim of this study was to estimate the efficacy of limbal-conjunctival autograft in the treatment of pterygium.

MATERIAL AND METHODS

We conducted a retrospective study including 15 patients (16 eyes) operated on for pterygium by limbal-conjunctival autograft. The examination included the search for risk factors and visual acuity, as well as corneal astigmatism and pterygium measurement. The follow-up included an examination at day 8, 1 month, and 3 months and assessed the integration of the transplant on the eye's surface, the aesthetic aspect, and recurrence. We describe the patients' characteristics, visual acuity, and astigmatism before and after surgery.

RESULTS

The mean age of the patients was 56 years (range, 31-81 years). Before surgery, irritative signs and astigmatism, were found in 37% and impaired visual acuity in 81%. The mean duration of the follow-up after surgery was 19 months. Visual acuity and astigmatism improved in 56% of our patients. All transplants and harvest sites had a satisfactory macroscopic aspect. However, one patient suffered from a corneal invasion by fibrovascular tissue, 7 months postoperatively, which remained stable at the end of follow-up.

DISCUSSION/CONCLUSION

In our study, the limbal-conjunctival autograft was a safe and effective surgical treatment with a very low recurrence rate at long-term follow-up.

[Development of human fetal neuroretina grafted into nude mice]

PURPOSE

To determine the role of different ocular tissues in the development of the human fetal neuroretina heterotopically implanted in nude mice.

MATERIAL AND METHODS

Fifty eight eyeballs obtained from legally aborted 6- to 7-week-old embryos or 8- to 10-week-old fetuses were heterotopically implanted in nude mice. Over a period of 1-245 days, all the grafts were removed for light and electron microscopy observations.

RESULTS

All grafts were successful. Twenty six exhibited a normal histological organization of the choriocapillaris, the retinal pigment epithelium, and the neuroretina in the posterior part of the eye. Photoreceptor differentiation was observable approximately 80 days after transplantation and was complete at 166 days. The anterior part of the retina was always dysplasic. Twenty three eyes had a dysplasic neuroretina with folds, rosettes, and necrotized areas. In absence of retinal pigment epithelium, the neuroretina was always dysplasic or absent. Nine eyes were atrophic without any differentiation of the neuroretina.

CONCLUSION

These results demonstrate that the development of a stratified neuroretina requires both rapid revascularization and normal development of retinal pigment epithelium. When these conditions are not met, the neuroretina becomes dysplasic or atrophic or disappears.

Morphologic and functional development of whole human fetal stomachs grafted into nude mice

To study in vivo the cellular differentiation and secretion of human developing fetal stomach, ethically and technically impossible to perform in utero, 256 fetal stomachs were xenografted. Human stomachs from 6- to 10-week-old fetuses were grafted for 1-273 days into nude mice. Biopsies for immunohistochemistry, hybridization and electron microscopy were taken and a catheter introduced into the human stomach. Macroscopic growth was fast and cells in S phase were numerous during the first 9 weeks, then the stomach size was stable and the gastric mucosa, of adult type, remained normal. In situ hybridization detected only a minute mouse mesenchymal chimerism in the graft. Chromogranin A, intrinsic factor and H+/K+ adenosine triphosphatase were immunohistolocally detected in epithelial cells 20 days after grafting, gastrin was detected after 30 days and pepsinogen after 60 days. The pH in gastric juice, which was at 8.0 +/- 0.1 from days 10-25, dropped from 4.39 +/- 1.80 at 30 days to 1.58 +/- 0.29 at 90 days. Intrinsic factor was stable and pepsin ranged from 6.8 +/- 7.8 to 134 +/- 51 units at 90 days. The differentiation of the epithelial cells in xenografts was very accelerated in comparison to that in utero.

[Dilated cardiomyopathy and panuveitis as presenting symptoms of Lyme disease. General review of one case]

INTRODUCTION

The clinical expression of Lyme disease is highly variable. If a patient presents clinical findings consistent with a systemic Lyme borreliosis, this disease must be considered in an endemic area because of its favorable outcome with adequate treatment.

EXEGESIS

The authors report and discuss the case of a patient with an unusual history of dilated cardiomyopathy and supraventricular fibrillation followed by bilateral panuveitis. Enzyme-linked immunosorbent assay and Western blot were positive for Borrelia burgdorferi antigens. The diagnosis of Lyme disease was made after other infectious, inflammatory and autoimmune disorders were excluded by clinical, instrumental and biological investigations. The treatment by ceftriaxone and amoxicillin resolved the ophthalmologic manifestations and improved the cardiac condition.

CONCLUSION

This report underlines the possibility of an unusual presentation of Lyme disease. Ophthalmologic and cardiac involvement should be known by clinicians.

[Endogenous aspergillus endophthalmitis: a case repport]

We report a case of endogenous aspergillus endophthalmitis. This infection occurred in a young immunocompromised boy of 6 years old. The localisation of the chorioretinitis was unusual because out of the posterior area. The evolution was favorable with recovering of the visual acuity under general treatment and intravitreous injections.