PubMed Health⌕ Search

Biomedical subjects

M Paques

Publications and source records attributed to M Paques.

At least 19 recordsLinked to original sources
PubMed2006

Familial central retinal vein occlusion.

AIM: To report four cases of central retinal vein occlusion (CRVO) in a French family. PATIENTS AND METHODS: Ophthalmological examination and medical work-up of seven members of the family. RESULTS: There were four cases of CRVO in two consecutive generations. Three of them had CRVO in both eyes. Arterial hypertension was present in two, associated to glaucoma in one. Medical work-up did not reveal additional risk factors. CONCLUSIONS: We report a case of familial clustering of CRVO. Our cases combined to other cases reported in the literature provide arguments for the existence in some subjects of a genetic predisposition of CRVO. Additional case series are however needed to confirm this hypothesis.

Adult↗
PubMed2006

Subretinal electrode implantation in the P23H rat for chronic stimulations.

BACKGROUND: In age related macular degeneration and inherited dystrophies, preservation of retinal ganglion cells has been demonstrated. This finding has led to the development of various models of subretinal or epiretinal implant in order to restore vision. This study addresses the development of a polyimide subretinal electrode platform in the dystrophic P23H rat in vivo. METHODS: A technique was developed for implanting a subretinal electrode into the subretinal space and stabilising the distal extremity of the cabling on the rat cranium in order to allow future electrical stimulations of the retina. RESULTS: In vivo imaging of the retina with the scanning laser ophthalmoscope demonstrated reabsorption of the surgically induced retinal detachment and the absence of major tissue reactions. These in vivo observations were confirmed by retinal histology. The extraocular fixation system on the rat cranium was effective in stabilising the distal connector for in vivo stimulation. CONCLUSION: This study demonstrates that a retinal implant can be introduced into the subretinal space of a dystrophic rat with a stable external connection for repeatable electrical measurements and stimulation. This in vivo model should therefore allow us to evaluate the safety and efficacy of electrical stimulations on dystrophic retina.

Animals↗
PubMed2005

Systolodiastolic variations of blood flow during central retinal vein occlusion: exploration by dynamic angiography.

BACKGROUND/AIM: In patients with acute central retinal vein occlusion (CRVO), dynamic angiography may reveal the presence of pulsatile flow (termed here pulsatile venular outflow, PVO) within first order veins (that is, the large veins). The main goal of this study was to investigate the mechanism underlying PVO. METHODS: 10 patients with CRVO and PVO were included. Quantitative and qualitative analysis of venous flow on dynamic angiograms allowed the correlation, temporally, of second and first order vein flow on the one hand, and venous flow and systolic cycle on the other. RESULTS: Analysis of the time-velocity curve showed that (1) the onset of arterial systole preceded the onset of PVO by less than 0.08 seconds (n = 5); (2) PVO onset was simultaneous to the time of onset of minimal flow (Vmin) in first order veins (n = 10); (3) the time of onset of maximal flow (Vmax) in first order veins occurred 0.20-0.44 seconds after the onset of PVO (n = 6). CONCLUSIONS: During CRVO with severe reduction in blood flow, the presence of PVO is the result of the existence of a distinct haemodynamic regimen in first and second order veins. These data support the hypothesis that second order veins flow is synchronous with the arterial flow, while the delayed peak flow in first order veins may reflect the consequences of the delayed IOP curve and/or of intermittent venous compression.

Acute Disease↗
PubMed2004

Heterogeneity of diabetes phenotype in patients with 3243 bp mutation of mitochondrial DNA (Maternally Inherited Diabetes and Deafness or MIDD).

OBJECTIVE: In patients with maternally inherited diabetes and deafness (MIDD), due to 3 243 A > G mutation of mitochondrial DNA (mtDNA), diabetes may present with variable phenotypes. OBJECTIVE: To ascertain the existence of two distinct phenotypes, MIDD1 and MIDD2, in a series of patients with MIDD. DESIGN: Multicenter prospective study. PATIENTS: 77 patients with diabetes and the mtDNA 3243 mutation and 139 control patients with type 1 (T1D) or type 2 (T2D) diabetes, matched according to initial presentation of diabetes, age at onset, sex, and duration of diabetes (24 T1D and 115 T2D, including 55 treated with insulin). MEASUREMENTS: Anthropometric characteristics (height, body weight, body mass index [BMI], sex), family history of diabetes, and characteristics of diabetes (age at onset, treatment, hemoglobin A1c [HbA1c]), extrapancreatic manifestations. RESULTS: In 13 cases (17%, MIDD1), diabetes presented as insulin-dependent from the onset, with ketoacidosis in 6 cases. In 64 cases (83%, MIDD2), diabetes resembled T2D, and was treated with diet in 12 cases, oral hypoglycemic agents in 21 cases, or insulin in 31 cases. Compared with patients with MIDD2, patients with MIDD1 were characterized by lower age at onset of first manifestation of MIDD (25.4 +/- 9.6 vs 33.7 +/- 13.2 Years, P<0.0005), lower body weight (49.1 +/- 7.4 vs 56.3 +/- 10.9 kg, P<0.0025), lower BMI (18.2 +/- 2.3 vs 20.9 +/- 3.6 kg/m2, P<0.0005), and higher HbA1c levels (9.5 +/- 2.0 vs 7.5 +/- 1.6%, P<0.0005). Frequency of family history of diabetes and of extrapancreatic manifestations was the same in both MIDD subtypes. No difference was found within the MIDD2 subtype when comparing patients treated with or without insulin. Compared with matched controls, patients with MIDD had a lower BMI (MIDD1/T1D 18.2 +/- 2.3 vs 24.0 +/- 3.6 kg/m2 and MIDD2/T2D 20.9 +/- 3.6 vs 30.2 +/- 5.9 kg/m2, P<0.0025). Lastly, male patients with MIDD had a shorter height than controls (MIDD1/T1D: 166.1 +/- 3.2 vs 177.3 +/- 6.6 cm and MIDD2/T2D: 168.4 +/- 7.2 vs 173.6 +/- 6.6 cm P<0.025). CONCLUSIONS: These results confirm the existence of two different phenotypes in MIDD, MIDD1 and MIDD2, which may be related to the severity of the mitochondrial disease. The role of other genetic and/or environmental factors in the variable phenotype of MIDD remains to be elucidated.

Adult↗
PubMed2002

[Circulatory consequences of retinal vein occlusions. Advantages of dynamic angiography].

PURPOSE: To compare angiographic features in patients with branch vein (BRVO) and central retinal vein occlusion (CRVO) and to discuss their possible significance. PATIENTS AND METHODS: Clinical and indocyanine green (ICG) videoangiographic data of 35 patients with CRVO and 5 patients with BRVO were reviewed. In order to more fully understand the significance of hemodynamic alterations, patients with a decrease in retinal flow velocity from other causes (optic neuritis, carotid-cavernous fistula, carotid artery stenosis) were compared to patients with vein occlusion. RESULTS: Whatever the type of occlusion, the most frequent abnormality was the presence of pulsatile venular outflow, which at the acute phase was present in the majority of cases. The decrease in arterial velocity was visualized by the presence of diastolic reversed flow. There was no correlation between visual prognosis and hemodynamic alterations. Apart from vein occlusion, the pulsatile venular outflow was present in situations where increased venous pressure was present. CONCLUSIONS: BRVO and CRVO have similar alterations of venous flow. Videoangiography can electively show pulsatile venular outflow and reverse diastolic arterial flow, and thus contributes additional information to conventional angiography. Pulsatile venular outflow is probably due to a combination of elevated venous pressure and decreased plasma velocity. Videoangiography provides new insight to the consequences of retinal vein occlusion and will possibly lead to a better understanding of the sequence of events that lead to visual loss.

Blood Flow Velocity↗
PubMed2001

Maternally inherited diabetes and deafness: a multicenter study.

BACKGROUND: Maternally inherited diabetes and deafness (MIDD), which is seen in 0.5% to 2.8% of patients with type 2 diabetes mellitus, is related to a point mutation at position 3243 of mitochondrial (mt) DNA. Its clinical description is incomplete. OBJECTIVE: To study the clinical presentation and complications of diabetes in patients with MIDD and to identify clinical characteristics that may help select diabetic patients for mtDNA mutation screening. DESIGN: Multicenter prospective descriptive study. SETTING: 16 French departments of internal medicine, diabetes and metabolic diseases, or both. PATIENTS: 54 patients with type 2 diabetes mellitus and the mtDNA 3243 mutation. MEASUREMENTS: Characteristics of diabetes, metabolic control (glycosylated hemoglobin level), complications of diabetes, and involvement of other organs. RESULTS: On average, patients with MIDD were young at diabetes onset and presented with a normal or low body mass index. None were obese. Seventy-three percent of probands had a maternal family history of diabetes. Diabetes was non-insulin-dependent at onset in 87% of patients; however, 46% of patients had non-insulin-dependent disease at onset but progressed to insulin therapy after a mean duration of approximately 10 years. Neurosensory hearing loss was present in almost all patients. Eighty-six percent of patients who received an ophthalmologic examination had macular pattern dystrophy (a specific retinal lesion). Forty-three percent of patients had myopathy, 15% had cardiomyopathy, and 18% (9 of 51) had neuropsychiatric symptoms. Although the prevalence of diabetic retinopathy was 8% among patients who received an ophthalmologic examination, lower than expected after a mean 12-year duration of diabetes, prevalence of kidney disease was 28%. This suggests that a specific renal involvement was the result of mitochondrial disease. CONCLUSIONS: Maternally inherited diabetes and deafness has a specific clinical profile that may help identify diabetic patients for mtDNA testing.

Adolescent↗
PubMed2001

Analysis of retinal and choroidal circulation during central retinal vein occlusion using indocyanine green videoangiography.

OBJECTIVE: To explore the hemodynamic changes and their correlation with clinical presentation during central retinal vein occlusion. MATERIALS AND METHODS: Retrospective, 2-center study. The medical records of 27 patients with central retinal vein occlusion were reviewed. For each patient, the plasma transit in central retinal vessels and in peripapillary choroidal vessels was analyzed using indocyanine green videoangiography. RESULTS: The incidence of alteration in retinal plasma transit, ie, pulsatile filling of arteries and/or veins and increased arteriovenous filling time, was inversely correlated to duration from the onset but not to funduscopic features. Among the 14 patients with less than 1 month's duration of symptoms, 3 developed chronic macular edema, and impairment of arterial flow preceded its onset. Among the 10 patients with opticociliary circulation, choroidal drainage routes were identified in 5 cases, with pulsatile filling in 3. CONCLUSIONS: Early in the course of central retinal vein occlusion, arterial and/or venous flow alterations are present, irrespective of visual acuity, vein dilation, or fundus hemorrhages. These alterations are less frequent in chronic than in recent-onset central retinal vein occlusion. The mechanisms of these alterations remain uncertain but may involve arterial constriction and/or intermittent venous compression. The relationship between these alterations in retinal flow and the secondary onset of macular edema or capillary nonperfusion deserves further investigation.

Adult↗
PubMed2001

Reproducibility of retinal mapping using optical coherence tomography.

OBJECTIVE: To assess the reproducibility of retinal thickness measurement using commercially available mapping software of optical coherence tomography (OCT). METHODS: Six radial scans, 6 mm long and centered on the fixation point, were performed on 10 eyes of 10 healthy volunteers and 10 eyes of 10 diabetic patients with clinically significant macular edema. Retinal thickness was measured automatically using the mapping software of OCT in the 9 macular Early Treatment Diabetic Retinopathy Study areas and in a central area 500 microm in diameter. Measurement reproducibility was tested by means of 3 series of scans performed by 2 different observers on 2 different days. Results were assessed by their repeatability and intraclass correlation coefficients (ICCs). RESULTS: In healthy subjects, intraobserver, interobserver, and intervisit reproducibility of retinal thickness measurements were excellent, with a repeatability coefficient of less than 7 microm and ICCs of greater than 0.89. In diabetic patients, the repeatability coefficient was less than 21 microm in all areas of the macula except one, with an ICC of greater than 0.98. Relative variations in measurements were small in both healthy and diabetic subjects, with reproducibilities of +/- 5% and +/- 6%, respectively. CONCLUSION: Retinal mapping software of OCT allows reproducible measurement of retinal thickness in both healthy subjects and diabetic patients with macular edema.

Adult↗
PubMed2001

Molecular evidence of true-to-type propagation of a 3-year-old Norway spruce through somatic embryogenesis.

Some progress has recently been made in establishing a system enabling somatic embryos to be initiated from old elite trees. We report here the first results demonstrating the molecular conformity of somatic embryos initiated from increasingly old Norway spruce (Picea abies (L.) Karst.), as indicated by an analysis of six nuclear microsatellites that showed an extremely high tendency to mutate during in vitro culture. No allelic difference was detected at these loci among plants regenerated from somatic embryos or between the former and mother plants. Moreover, phenotypical data acquired on the same 3- to 9-year-old plants growing in the field sampled for molecular analyses were totally in accord with the results on molecular conformity.

Cloning, Molecular↗
PubMed2001

Dissociated optic nerve fiber layer appearance of the fundus after idiopathic epiretinal membrane removal.

PURPOSE: To report the appearance of the fundus, that is seen frequently after removal of an idiopathic epiretinal membrane and which we refer to as the dissociated optic nerve fiber layer appearance. DESIGN: Interventional, noncomparative retrospective case series. PARTICIPANTS: One hundred consecutive patients with an epiretinal membrane who underwent pars plana vitrectomy and epiretinal membrane peeling in one eye. METHODS: Only patients with an idiopathic epiretinal membrane or a membrane associated with a peripheral retinal tear, but without retinal detachment, were considered for this study. Sixty-one patients met these criteria for one eye. Preoperative and postoperative best-corrected visual acuity and preoperative and postoperative blue filter fundus photographs were reviewed. Histopathologic specimens of epiretinal membranes were available for 14 eyes. MAIN OUTCOME MEASURES: The postoperative incidence of the dissociated optic nerve fiber layer appearance on blue filter photographs, visual acuity changes, and the presence of internal limiting membrane in epiretinal membrane specimens. RESULTS: The postoperative incidence of this feature on blue filter fundus photographs was 43%. No difference was found between eyes with or without this feature concerning the average preoperative and postoperative best-corrected visual acuity or the average change in visual acuity. Internal limiting membrane was present in all 14 epiretinal membrane specimens available. Five of these 14 patients concerned exhibited a dissociated optic nerve fiber layer appearance and 9 did not. CONCLUSIONS: The dissociated optic nerve fiber layer appearance occurred frequently after removal of an epiretinal membrane. As far as we know, this feature has not been previously reported. It consisted of numerous arcuate striae within the posterior pole in the direction of the optic nerve fibers and slightly darker than the surrounding retina. This feature had no functional effect noticeable by the patient and did not preclude good visual recovery. The small number of histologic samples and the impossibility of quantifying the area of internal limiting membrane peeled off did not allow us to supply proof that this feature is due to the extensive peeling of the internal limiting membrane, although this is the most likely hypothesis.

Aged↗
PubMed2001

[Value of local ophthalmic artery fibrinolysis in severe forms of central retinal vein occlusion].

PURPOSE: To assess the value of selective ophthalmic artery thrombolysis as a treatment for central retinal vein occlusion (CRVO) for which no alternative therapy is available. MATERIALS AND METHODS: Patients included in this study presented with recent severe non-ischemic CRVO. Urokinase (300,000 IU) was perfused for 40 minutes into the ophthalmic artery. Visual acuity, fundoscopy and retinal arteriovenous transit time were assessed during one year of follow-up. RESULTS: Five of the 13 patients treated experienced a marked improvement of vision (p = 0.05) and retinal perfusion within 24-48 hours, and exhibited progressive lesion regression at fundoscopy within 2-4 weeks. The clinical course of the 5 patients prior to treatment resembled that of combined central retinal artery and vein obstruction (CRAO/CRVO), which typically has a poor visual outcome. One patient relapsed 1 month after thrombolysis. No technical complications were observed. CONCLUSION: Although there was no control group, the short period between fibrinolysis and significant visual improvement combined with marked retinal perfusion improvement, suggests that local thrombolysis is beneficial for CRVO, especially recent CRAO/CRVO.

Adult↗
PubMed2001

[Management of diabetic complications during pregnancy using diabetic retinopathy as an example].

Pregnancy may adversely affect the natural course of diabetic retinopathy (DR). Reported rates of new cases or progression of DR during pregnancy range from 10% to 70%. Regression of some of the nonproliferative vascular changes have been reported after delivery. Several risk factors contribute to the aggravation of DR, such as pregnancy itself, duration of the diabetes, elevated glycohemoglobin level, degree of retinopathy at the beginning of the pregnancy, rapid normalization of blood glucose level. The mechanisms by which pregnancy may alter the course of DR is not elucidated: worsening of DR may be due to modifications of retinal blood flow, or to increase in circulating growth factors levels. Careful ophthalmologic monitoring during pregnancy is required. Fundus examination should be performed before pregnancy or at the beginning of it. In patients with no retinopathy, fundus examination should be performed every three months. In those with diabetic retinopathy, fundus examination should be repeated every month. In eyes with proliferative DR or severe nonproliferative DR before pregnancy or at its beginning, laser photocoagulation should be performed promptly.

Biomarkers↗
PubMed2000

The Application of Diffusing-Wave Spectroscopy to Monitor the Phase Behavior of Emulsion-Polysaccharide Systems.

Droplet aggregation is an important cause of instability in emulsions because it may, on one hand, lead to an increased creaming rate, resulting in fast separation of a concentrated emulsion phase (creamed layer). On the other hand, it may also lead to the formation of a stabilizing, droplet-based network. Early detection of instability is often difficult due to the high turbidity and viscosity of more concentrated food emulsions. The applicability of diffusing-wave spectroscopy (DWS) for monitoring droplet aggregation and creaming was studied using a model system consisting of a protein-stabilized emulsion, to which a soluble polymer ("thickener") was added. This addition leads to an increased solvent viscosity and may induce droplet aggregation. In addition, the redistribution process of emulsion droplets in aggregating concentrated emulsions was directly observed by confocal scanning laser microscopy (CSLM). By DWS the decrease of the droplet mobility caused by the viscosity increase of the continuous phase could be separated from the effect of droplet aggregation. Moreover, a distinction could be made between aggregation, leading to increased creaming rates and that leading to the formation of a stabilizing droplet network. The potential of DWS for in situ measurement of the stability of concentrated emulsions is discussed. Copyright 2000 Academic Press.

Journal Article↗
PubMed2000

Optical coherence tomography of idiopathic macular epiretinal membranes before and after surgery.

PURPOSE: To examine the preoperative and postoperative anatomical features of the macula using optical coherence tomography in patients who underwent surgery for epiretinal membrane and to correlate these features with functional results. METHODS: In a noncomparative interventional series, 62 eyes of 62 consecutive patients operated on for an idiopathic epiretinal membrane were followed up using a standardized protocol. Preoperative and postoperative examination included best-corrected visual acuity using an Early Treatment Diabetic Retinopathy Study chart, biomicroscopy of the fundus with a contact lens, fundus photography with blue and green filters, fluorescein angiography, and optical coherence tomography. RESULTS: Median preoperative visual acuity was 20/60 (range, 20/32 to 20/320). Median postoperative visual acuity was 20/40 (range, 20/20 to 20/160). Fifty-one eyes (82%) obtained visual acuity of 20/50 or better. Preoperatively, all eyes had increased macular thickness (mean, 419 +/- 105 microm; range, 265.5 to 689 microm), with disappearance of the foveal pit. An epiretinal membrane was visible on optical coherence tomography scans in 26 cases (42%). Intraretinal cystic spaces were present in the thickened macular tissue in 15 cases but corresponded to cystoid macular edema on fluorescein angiography in only three. Postoperatively, mean macular thickness decreased to 300 +/- 65 microm (range, 185 to 511 microm) but returned to normal in only three eyes. The foveal pit reappeared in 20 eyes. Preoperatively, visual acuity correlated with macular thickness (r = 0.56, P <.0001), but not postoperatively (r = 0.12, P =.37). CONCLUSION: Macular thickness decreases after epiretinal membrane surgery, but the macular profile rarely returns to normal. However, this does not preclude satisfactory improvement of visual acuity.

Aged↗
PubMed2000

Central retinal artery occlusion associated with head or neck pain revealing spontaneous internal carotid artery dissection.

PURPOSE: To report two cases of head or neck pain and central retinal artery occlusion associated with spontaneous dissection of the ipsilateral internal carotid artery. METHODS: Case reports. RESULTS: We describe two cases of sudden visual loss caused by central retinal artery occlusion. Both cases were preceded by ipsilateral headaches or neck pain and tinnitus. The patient had no other neurological signs or history of trauma. In both cases, cerebral angiography revealed ipsilateral internal carotid artery dissection. CONCLUSION: Ipsilateral headache or neck pain with tinnitus preceding central retinal artery occlusion is highly suggestive of internal carotid artery dissection. Early diagnosis and treatment may reduce the risk of hemispheric stroke.

Adult↗
PubMed2000

Acute transient myopia induced by indapamide.

PURPOSE: To report on a case of acute transient myopia associated with ciliochoroidal detachment induced by indapamide. METHOD: Case report. Clinical examination, ultrasonography, and fluorescein angiography were performed during the acute phase of disease and convalescence. RESULTS: After indapamide was discontinued, acute bilateral myopia, which was associated with anterior chamber shallowing and diffuse choroidal thickening, resolved spontaneously 8 days after onset. The initial angiography showed scattered islands of delayed fluorescein filling that disappeared without any permanent change by day 30. CONCLUSION: Indapamide can induce spontaneously resolving transient myopia associated with diffuse choroidal thickening.

Acute Disease↗