18F-FDG brain PET hypometabolism in patients with long COVID.

PURPOSE: In the context of the worldwide outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), some patients report functional complaints after apparent recovery from COVID-19. This clinical presentation has been referred as "long COVID." We here present a retrospective analysis of 18F-FDG brain PET of long COVID patients from the same center with a biologically confirmed diagnosis of SARS-CoV-2 infection and persistent functional complaints at least 3 weeks after the initial infection. METHODS: PET scans of 35 patients with long COVID were compared using whole-brain voxel-based analysis to a local database of 44 healthy subjects controlled for age and sex to characterize cerebral hypometabolism. The individual relevance of this metabolic profile was evaluated to classify patients and healthy subjects. Finally, the PET abnormalities were exploratory compared with the patients' characteristics and functional complaints. RESULTS: In comparison to healthy subjects, patients with long COVID exhibited bilateral hypometabolism in the bilateral rectal/orbital gyrus, including the olfactory gyrus; the right temporal lobe, including the amygdala and the hippocampus, extending to the right thalamus; the bilateral pons/medulla brainstem; the bilateral cerebellum (p-voxel < 0.001 uncorrected, p-cluster < 0.05 FWE-corrected). These metabolic clusters were highly discriminant to distinguish patients and healthy subjects (100% correct classification). These clusters of hypometabolism were significantly associated with more numerous functional complaints (brainstem and cerebellar clusters), and all associated with the occurrence of certain symptoms (hyposmia/anosmia, memory/cognitive impairment, pain and insomnia) (p < 0.05). In a more preliminary analysis, the metabolism of the frontal cluster which included the olfactory gyrus was worse in the 7 patients treated by ACE drugs for high blood pressure (p = 0.032), and better in the 3 patients that had used nasal decongestant spray at the infectious stage (p < 0.001). CONCLUSION: This study demonstrates a profile of brain PET hypometabolism in long COVID patients with biologically confirmed SARS-CoV-2 and persistent functional complaints more than 3 weeks after the initial infection symptoms, involving the olfactory gyrus and connected limbic/paralimbic regions, extended to the brainstem and the cerebellum. These hypometabolisms are associated with patients' symptoms, with a biomarker value to identify and potentially follow these patients. The hypometabolism of the frontal cluster, which included the olfactory gyrus, seems to be linked to ACE drugs in patients with high blood pressure, with also a better metabolism of this olfactory region in patients using nasal decongestant spray, suggesting a possible role of ACE receptors as an olfactory gateway for this neurotropism.

Input-output transformation in the visuo-oculomotor loop: comparison of real-time optical imaging recordings in V1 to ocular following responses upon center-surround stimulation.

In psychophysics and physiology, it is well established that lateral interactions are crucial mechanisms to constrain response normalization and contextual modulations. To study the cortical mechanisms involved in the contextual modulation of the behavioral contrast response function, we compared in behaving monkeys the Ocular Following Response (OFR) to V1 population activity measured using Optical Imaging of Voltage-Sensitive Dyes (VSD). If contrast response functions (CRF) to a simple local stimulus are similar in V1 and in the OFR, lateral interaction leads however to quite different modulation at those two levels. At the behavioural level, contrast response function is strongly suppressed by lateral interactions, and this suppression is stronger for higher contrasts. In V1, we showed a slow dynamic of facilitation for low contrasts integration and a fast suppression operating on high contrasts. These modulatory interactions influence differently the contrast response functions, interrupting the dynamic increase of contrast sensitivity in OFR, but not in V1 response. The temporal properties of those effects lead us to hypothesize that horizontal and feedback connectivity have differential effect on low and high contrasts integration in V1. V1 provides then an input to MT whose contextual dependency is not totally determined and must be refined before affecting the behavioural OFR.

[Use of silicone oil for temporary tamponade in the treatment of retinal detachment with vitreoretinal retraction. 1. Short- and long-term anatomic and functional results in 110 cases]. / Utilisation de l'huile de silicone en tamponnement transitoire dans le traitement des décollements de rétine avec rétraction vitréo-rétinienne. Première partie: Résultats anatomiques et fonctionnels à court et long termes sur 110 cas.

Vitreoretinal retraction treated by silicone oil injections to provide internal tamponade after vitrectomy showed total reapplication in 28.2%, persistent residual detachment with a flat posterior pole in 18.2%, and a measurable visual acuity in 40%, including 10% of patients in show it was superior to 2/10. When immediate postoperative visual acuity could be measured this good result remained stable. When relapse occurred in spite of the presence of the silicone, it involved patients with the lowest postoperative visual acuity due to progressive major retinal fibrosis. These findings suggest that silicone oil injection is a valid procedure for treatment of retinal detachment requiring internal tamponade, and that perhaps its earlier use is indicated. Part 2 discusses its tolerance of this material.

[Use of silicone oil for temporary tamponade in the treatment of retinal detachment with vitreoretinal retraction. 2. Aspects, prevention and treatment of complications]. / Utilisation de l'huile de silicone en tamponnement transitoire dans le traitement des décollements de rétine avec rétraction vitréo-rétinienne. Deuxième partie: Aspects, prévention et traitement des complications.

A retrospective study of 36 cases of retinal detachment with vitreoretinal retraction, greatly improved immediately after intravitreal cavity injection of silicone was definitely responsible for two complications: cataract and chronic corneal edema. Their onset requires routine extraction of the silicone, recurrence of the retinal detachment developing in only 50% of cases. Used as a transient procedure, the injection of silicone into the vitreal cavity appears to be a relatively simple surgical procedure for detachments requiring prolonged internal tamponade.

[A fundus flavimaculatus associated with preretinal new vessels (author's transl)]. / Un cas de fundus flavimaculatus avec néovaisseaux prérétiniens.

Case report of a Fundus flavimaculatus associated with preretinal new vessels in a patient without family history. The problem discussed is the outcome of the retinal vascularization during the progressive atrophy of retinal cells.

[Retinal detachment following extraction of an intraocular foreign body. Effects of vitrectomy]. / Décollement de rétine après extraction d'un corps étranger intra-oculaire. Influence de la vitrectomie.

Intra-ocular foreign bodies have an extremely poor prognosis, retinal detachment with vitreo-retinal retraction being the main factor of treatment failure. Vitrectomy appears to be an effective method for preventing this complication. 77 patients with intra-ocular foreign bodies were studied in two separate groups: 45 patients in group I did not have preventive vitrectomy and 23 developed retinal detachments; 32 patients in group II did have preventive vitrectomy within 3 weeks following foreign body extraction, and only 6 patients developed retinal detachment. Vitreous hemorrhage and cataract were present in all cases with retinal detachment. The retinal detachment rate was significatively different between group I and II. Early vitrectomy seems to be effective in preventing retinal detachment after an intra-ocular foreign body. However, others factors still have to be studied: cataract, hemorrhage, contusion.

[Drug addiction and endophthalmitis due to Candida albicans : diagnostic and therapeutic problems (author's transl)]. / Toxicomanies et endophtalmies à Candida albicans : problèmes diagnostiques et thérapeutiques.

Mycotic endophthalmitis has a poor prognosis particularly when it occurs in drug addicts. Ten ocular manifestations have been studied. These endophthalmitis all appeared after intravenous heroin injections. In one case, Candida albicans was found in the vitrectomy liquid. In two others cases, the mycosis was suspected after electrosynerese. Treatment gave different results because of the slight penetration of the different drugs into the eye. A therapeutic trial was conducted : 4 patients underwent vitrectomy raising the problem of surgical treatment of these affections.

[Concerning: aging, the beginning of dialysis, the beginning of dependence: repercussions on the psychopathology of the very old dialysis patient]. / Le point sur: vieillissement, entrée en dialyse, entrée en dépendance: répercussion sur le psychisme du patient dialysé très âgé.

The incidence of psychopathology, particularly depression, is high in dialysed elderly patients whereas their perceived level of health in the mental domain is similar to that of a non-dialysed and, even younger, population. Although the losses associated with advancing years, chronic disease and then entry into dialysis renders the psyche of elderly people frail, they do not strictly add in negative terms: their psychological reserve or resignation helps very elderly people to tolerate dialysis and its constraints. However, maintaining functional autonomy (ability to provide for one's fundamental needs and preserve leisure activities) while remaining independent to take decisions (particularly in controlling ways of receiving assistance) and preserving close relationships emerge as major determinant factors of the quality of life of very elderly dialysed patients. Added to the dependency due to dialysis, losses in these domains very often represent a turning point by changing the patient's identity, predisposing to the development of relationship problems, leading the patient to question his self-esteem or even resulting in psychological dependency, which itself adversely affects the quality of life. These mechanisms of psychopathology may not hide the possibility of an underlying dementia.

[Symptoms and quality of life of hemodialysis patients aged 75 and over]. / Symptômes et qualité de vie de patients hémodialysés de plus de 75 ans.

BACKGROUND: The population of dialysed patients includes an increasing percentage of very elderly patients. Although their life expectancy continues to increase, there are few currently available data about their quality of life. OBJECTIVES: descriptive analysis of the determinants of quality of life, perceptual level of health and quality of life, and estimation of symptomatic complaints in a population of very elderly haemodialysed patients. METHOD: Study of 35 haemodialysed patients aged 75 years old and older, who answered a questionnaire divided into 7 parts, defining: the determinants of their quality of life by open-ended questions, the prevalence of complaints amongst 35 pre-determined symptoms, Folstein MMSE performance, scores on Katz (ADL) and Lawton (IADL) independence scales, SF-36 perceptual health scale, and score subjectively allocated by the patients to their quality of life. RESULTS: Maintenance of functional autonomy, independence in the decision-making process and maintaining good relationships with friends and family were major determinants of quality of life. Asthenia, the major complaint, was well reflected the reduced physical capabilities of the patients (mean SF-36 physical score: -1.1 SD). Despite the high prevalence of incapacitating painful symptoms (42%) and psychological symptoms (23%), autonomy remained satisfactory (mean ADL score: 5.6 out of 6 and IADL: 58%). The levels of perceptual health and of quality of life remained satisfactory for the majority of patients (mean mental SF-36 score: -0.06 SD, and 84% of the patients scored their quality of life > 5 out of 10). CONCLUSION: These figures indicate the considerable resources that these patients could mobilise. It also emerges as an additional argument against the exclusion, based only on the criteria of age and multiple pathologies, of the oldest patients from the access to dialysis.