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Biomedical subjects

L Laroche

Publications and source records attributed to L Laroche.

At least 73 records · Page 4Linked to original sources

[Correlation between corneal topography and subjective refraction in idiopathic and surgery-induced astigmatism].

PURPOSE: To study the correlation between subjective refraction and corneal topography. To compare the topographic analysis of surgically induced astigmatism (cataract and penetrating keratoplasty) with that of idiopathic astigmatism. METHODS: Subjective astigmatism, subjective spherical equivalent, best spectacle-corrected visual acuity (LogMAR units), and videokeratoscopy using the EyeSys 2000((R)) device (axial, tangential, and refractive power) were recorded in 100 eyes with idiopathic astigmatism, 100 eyes after cataract surgery, and 100 eyes after penetrating keratoplasty. Topographies were classified according to pattern (Bogan classification) and asphericity (shape factor: prolate or oblate). RESULTS: The asphericity shape distribution was significantly different between the 3 groups (p<0.001). The shape of idiopathic astigmatism was almost always prolate (90%) whereas the oblate shape was more frequent in the penetrating keratoplasty group (75%). There was no significant difference in topographic pattern distribution between the 3 groups (p=0.11). The asymmetric bow tie pattern was the most common topographic pattern. Topography pattern classification was significantly correlated with the subjective astigmatic cylinder. (r(s)=0.60, p<0.001). Unlike the round and oval patterns, the bow tie pattern was associated with the high subjective cylinder. Correlation between the subjective cylinder, the refractive power cylinder, and the axial power cylinder was strong (r(s)=0.92 p<0.001), but it was weak for the tangential power cylinder (r(s)=0.72 p<0.001). The correlation between the subjective spherical equivalent and central cornea power was poor (r(s)<0.37, p<0.001). Subjective astigmatic cylinder showed the strongest correlation with best spectacle-corrected visual acuity (r(s)=0.70, p<0.001), whereas the predicted corneal acuity, corneal uniformity index, asphericity, and refractive power symmetry index were poorly correlated with it (r(s)<0.54, p<0.001). CONCLUSION: Despite the difference in the asphericity shape, the topographic pattern was similar in the 3 groups. The pattern type was significantly correlated with the subjective astigmatic cylinder. Topographic indices failed to predict visual acuity, while the subjective cylinder showed a strong correlation with visual acuity.

Astigmatism↗

[Urrets-Zavalia syndrome].

We report four cases of Urrets-Zavalia Syndrome (fixed dilated pupil with iris atrophy) observed after penetrating keratoplasty. The precise etiology of the syndrome is uncertain and different mechanisms are reviewed. Care should be taken to avoid the use of mydriatic eye drops after penetrating keratoplasty.

Adult↗

[The Wiedemann-Beckwith syndrome and a congenital cataract].

Wiedemann-Beckwith syndrome is a congenital syndrome with characteristic abnormalities: omphalocele, macroglossia, neonatal gigantism, visceromegaly, hemihypertrophy and a predisposition to embryonic tumors. Ophthalmologic abnormalities have not been described with Wiedemann-Beckwith syndrome. The authors report one case of Wiedemann-Beckwith syndrome associated with bilateral congenital cataract. Family studies indicate linkage of the Wiedemann-Beckwith syndrome locus to the marker 11p15,5. The genetics of cataract is heterogenic. Several mutations responsible for congenital cataract have been described. The association of the Wiedemann-Beckwith syndrome and cataract may contribute to the understanding of the genetics of congenital cataract.

Beckwith-Wiedemann Syndrome↗

[Infectious keratitis after penetrating keratoplasty].

PURPOSE: To investigate the prevalence of microbial keratitis, predisposing risk factors, the spectrum of pathogens and the prognosis for graft survival and visual outcome in patients who developed microbial keratitis following penetrating keratoplasty (PK). MATERIAL: and methods: We reviewed 16 cases (15 patients) of microbial keratitis after PK. In all cases, corneal scrapings were obtained and microbiologically analyzed. Efficacy of treatment was evaluated by anatomical (clarity of graft) and visual recovery. RESULTS: Principal indications for PK were pseudophakic bullous keratopathy (50%) and microbial keratitis in the previous graft (25%). Sixty-three per cent of infections occurred within 1 year of PK. Principal predisposing risk factors were suture-related problems (44%) and microbial keratitis in the previous graft (25%). All of the scrapings were positive according to the microbiological evaluation with gram-positive cocci (64%), gram-positive rods (12%), fungi (18%), and Acanthamoeba (6%). We found 1 case of polymicrobial infection. Best visual and anatomical results were observed in nonadvanced cases and/or these treated early. After medical and surgical treatments, 8 patients (50%) had a clear graft and 10 patients (63%) had visual acuity less than 20/200. CONCLUSION: Postoperative control of risk factors and early recognition of infectious complications may decrease the incidence of severe microbial keratitis after PK.

Acanthamoeba Keratitis↗

[Change in refraction and topography after penetrating keratoplasty suture removal].

PURPOSE: To study the refractive and topographic modifications induced by penetrating keratoplasty suture removal. METHODS: We prospectively studied 80 corneas from 80 patients who had undergone penetrating keratoplasty. All of the eyes were examined before and after all sutures were removed, respectively at 10.9 5.1 months and 21.5 9.6 months after keratoplasty. Subjective refraction, best spectacle-corrected visual acuity (LogMAR units), keratometry, and corneal topography using the EyeSys 2000((R)) device (axial tangential and refractive power) were recorded. Topographies were classified according to the pattern (Bogan classification) and the asphericity shape (prolate and oblate). RESULTS: Best spectacle-corrected visual acuity (Log MAR units) increased significantly after suture removal (1.1 1.9 lines, plt; 0.001). Suture removal decreased the subjective cylinder (5.01 D 2.06 with suture, 4.11 2.08 without suture; p=0.009). The change in subjective cylinder correlated with the change in topographic pattern(s)=0.67 p<0.001). Conversely to the "bow tie" patterns, the other topographic patterns were more frequent after suture removal. The change in visual acuity was essentially explained by the change in subjective cylinder(s)=0.40 p=0.002). The average central corneal power decreased significantly after suture removal by 0.83 to 1.81 D (p<0.001), whereas the subjective spherical equivalent increased (hyperopization) (-4.07D 3.73 with suture, -3.48 3.40 without suture; p=0.02). The change in central corneal power significantly correlated with the change in subjective spherical equivalent (r(s)()>0.30 plt; 0.001). The corneal power of the mid-periphery did not significantly change after suture removal. Suture removal significantly modified the asphericity shape distribution. (majority of prolate shape with suture, majority of oblate shape without suture, p<0.001). CONCLUSION: Keratoplasty sutures induce a central bulge in the corneal graft. Suture removal induces a decrease in the subjective cylinder and it increases the subjective spherical equivalent (hyperopization) through a decrease in the central corneal power. Suture removal modifies the corneal topographic pattern and shape. Visual acuity improvement after suture removal is mainly explained by the decrease in subjective astigmatism.

Adolescent↗

[Ocular biometric measurements with a slit-lamp method (Orbscan)].

PURPOSE: To evaluate the accuracy and reproducibility of the biometric measurements obtained with the Orbscan((R)) device in normal eyes. METHODS: Anterior chamber depth, axial length, and corneal diameter were studied in 50 normal eyes of 25 patients using the Orbscan((R)) device and A-Scan ultrasonography. For each eye, two exams were done successively and reproducibility was calculated by analyzing the difference between both measurements. RESULTS: The reproducibility of anterior chamber depth and corneal diameter measurements obtained by Orbscan((R)) was high (respectively 0.721.25% and 0.831.40%). The anterior chamber depth measurements by Orbscan((R)) and A-Scan ultrasonography were strongly correlated (rs=0.92;p<0.001). The axial length measurement obtained with the Orbscan((R)) device was less reproducible (3.554.11%). For the axial length, the Orbscan((R)) measurements and A-Scan ultrasonography measurement was poorly correlated. (rs=0.64; p<0.001). CONCLUSION: The anterior chamber depth measurement obtained with the Orbscan((R)) device showed high reproducibility and it was strongly correlated with the measurement obtained by A-Scan ultrasonography. Axial length measurement obtained with the Orbscan((R)) device was less reproducible and poorly correlated with the A-Scan ultrasonography measurement. It was not relevant for clinical application.

Adult↗

[Idiopathic polypoidal choroidal vasculopathy leading to blindness].

Idiopathic polypoidal choroidal vasculopathy (IPCV) has recently been recognized as a distinct cause of recurrent subretinal hemorrhages and exudates as well as multiple hemorrhagic retinal pigment epithelium detachments in the macula. IPCV is usually considered to have a good visual prognosis. We report the case of a 44-year-old woman with particularly severe bilateral macular and peripheral IPCV. The patient was followed for 13 years and had final visual acuity of counting fingers in the right eye and 20/400 in the left eye. Patients with IPCV with macular choroidal neovascularization tend to have a poor visual prognosis. This case of IPCV should alert the physician to be particularly attentive to the follow-up of these patients.

Blindness↗

[Precision and reliability of Orbscan and ultrasonic pachymetry].

PURPOSE: To compare the accuracy and reproducibility of the orbscan pachymetry and ultrasonic pachymetry in the normal eye and in the penetrating keratoplasty eye. METHODS: Pachymetric measurements were assessed in 50 eyes of 25 normal patients and 50 eyes of 48 patients who had undergone penetrating keratoplasty using both Orbscan II and ultrasonic pachymetry (Tomey SP-2000). For each eye, 2 successive measures were recorded with both instruments. For both devices, the default setting was used. Orbscan pachymetry maps were divided into 5 groups using a modification of Liu's classification. RESULTS: Orbscan pachymetry strongly correlated with ultrasonic pachymetry (rs = 0.91; p < 0.001). Ultrasonic pachymetry values and Orbscan pachymetry values showed no significant differences in the normal group (respectively, 557 microns +/- 36 and 555 microns +/- 34; p > 0.05). Ultrasonic pachymetry values and orbscan pachymetry values were significantly different in the penetrating keratoplasty group (respectively, 571 microns +/- 52 and 550 microns +/- 54; p < 0.001). The best value for the acoustic factor for Orbscan pachymetry in the penetrating keratoplasty group was 0.89. Ultrasonic pachymetry reproducibility and Orbscan pachymetry reproducibility were not significantly different (0.86% +/- 0.61 v. 0.67% +/- 0.63; p = 0.13 in the normal group; 1.22% +/- 0.81 v. 1.23% +/- 1.13; p = 0.92, in the penetrating keratoplasty group). Both pachymetry methods showed less reproducibility in the penetrating keratoplasty group than in the normal group (p < 0.02). Thinnest point localization was significantly different in both groups (p < 0.001). In 66% of the normal group, the thinnest point of the cornea was located in inferotemporal quadrant. This point was located at an average of 0.63 +/- 0.25 mm from the visual axis in the normal group and 1.60 +/- 0.81 mm in the penetrating keratoplasty group (p < 0.001). Whereas "Centered round" (40%) and "centered oval" (34%) were the most common patterns in the normal group, "decentered oval" (40%) and "irregular" (30%) were more frequent in the penetrating keratoplasty group (p < 0.001). CONCLUSION: Orbscan pachymetry strongly correlated with ultrasonic pachymetry. Reproducibility of both methods is excellent and not significantly different. Thinnest point localization and pachymetric map classification are significantly different in normal eyes and in penetrating keratoplasty eyes.

Child↗

[Study of visual field and vigabatrin treatment in children].

INTRODUCTION: Concentric visual field defects have been described in association with vigabatrin, a GABA mimetic antiepileptic agent. Few cases have been reported in children. METHODS: A systematic ophthalmological examination was performed in 14 children treated with vigabatrin for seizures. A manual kinetic perimetry test (Goldmann) was done in 11 cases. The ERG was recorded in the 3 cases where perimetry could not be done. RESULTS: All children were asymptomatic. The mean age was 9.6 years. The mean duration of vigabatrin treatment was 41 months. The visual field was abnormal when central and peripheral fields were constricted. A visual field defect was discovered in 6 cases: 4 were severe, 2 were mild. When vigabatrin treatment was stopped, 1 case became worse, 1 case was slightly better, and 1 case remained stationary. A disturbed ERG was found in 3 children (depressed b-wave, raised a/b ratio). CONCLUSION: The visual field defects discovered in children treated with vigabatrin are similar to those described in adults. The incidence and progression of visual field constriction in children with and after vigabatrin treatment are not yet well known. Children treated with vigabatrin should therefore have systematic and regular ophthalmological perimetry, and ERG examinations.

Adolescent↗

Diagnostic value of dominant T-cell clones in peripheral blood in 363 patients presenting consecutively with a clinical suspicion of cutaneous lymphoma.

It is now widely accepted that polymerase chain reaction (PCR) analysis of cutaneous T-cell clonality is of diagnostic value in cutaneous T-cell lymphomas (CTCLs) and most helpful in the diagnosis of mycosis fungoides (MF). However, the diagnostic and prognostic value of circulating clonal T cells remains unclear. We studied T-cell clonality in the peripheral blood (PB) and the cutaneous lesion, sampled at the same time, in 363 consecutively seen patients with a clinical suspicion of cutaneous lymphoma. Using a PCR technique providing a specific imprint of T-cell clones (PCRgamma-denaturing gradient gel electrophoresis), we found that detection of identical circulating and cutaneous T-cell clones was associated with the diagnosis of CTCL (P <.001). Detection of circulating tumor cells in patients with MF was infrequent (12.5%), except in those with erythrodermic MF (42%; P =.003). Moreover, among the 46 patients who had identical circulating and cutaneous T-cell clones, 25 (56%) had erythroderma. The finding of a dominant clone in the PB but not in the skin was frequent, regardless of the clinicohistologic classification; it occurred in 30% of patients with CTCL, 41% with non-CTCL malignant infiltrates, and 34% with benign infiltrates. This pattern was significantly more frequent in patients over 60 years of age (P <.002), even in the CTCL group (P <. 01). In conclusion, dominant T-cell clones detected in the PB of patients with MF by using a routine PCR technique are rarely tumoral and are more often related to age. A multicenter prospective study is under way to establish the prognostic value of circulating tumor cells.

Adult↗

Cloning and characterization of the murine toll-like receptor 5 (Tlr5) gene: sequence and mRNA expression studies in Salmonella-susceptible MOLF/Ei mice.

Toll-like receptors (TLRs) are a group of evolutionarily conserved pattern recognition receptors involved in the activation of the immune system in response to various pathogens. In this paper, we describe the cloning and characterization of the mouse homologue of human TLR5. Mouse Tlr5 encodes a 859-amino-acid protein that contains an N-terminal signal sequence, a leucine-rich repeat extracellular domain, a short transmembrane domain typical of type I transmembrane proteins, and a Toll/interleukin-1R signaling domain characteristic of all TLR proteins. The mouse Tlr5 protein shows 81% homology to human TLR5 and approximately 40% similarity to other TLR family members. Northern blot analysis reveals that Tlr5 is expressed predominantly in liver and lung with low-level expression in most other tissues examined. We have mapped Tlr5 to distal chromosome 1 using the (C57BL/6J x Mus spretus) x C57BL/6J Jackson BSB panel as well as a (C57BL/6J x MOLF/Ei)F(2) panel with the following position: D1Mit112-8.0 cM-Tlr5-9.6 cM-D1Mit17. The presence of a quantitative trait locus for susceptibility to Salmonella typhimurium on distal chromosome 1 prompted the examination of Tlr5 in susceptible MOLF/Ei mice. Polymorphic sequence variants in Tlr5 allowed us to identify a unique 4-allele haplotype in MOLF/Ei. Furthermore, using both Northern blot analysis and reverse transcription-polymerase chain reaction, we have shown a reduced expression of Tlr5 during infection of MOLF/Ei mice with Salmonella. The assignment of Tlr5 to a chromosomal region known to harbor a Salmonella-susceptibility locus together with decreased expression of Tlr5 mRNA in liver of susceptible MOLF/Ei mice suggests the possibility that, as with other members of this family, Tlr5 may play a role in host response to bacterial gram-negative infections.

Amino Acid Sequence↗

Cutaneous involvement in patients with angioimmunoblastic lymphadenopathy with dysproteinemia: a clinical, immunohistological, and molecular analysis.

OBJECTIVE: To determine whether cutaneous involvement in patients with angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) is related to a clonal T-cell proliferation. DESIGN: Retrospective study. SETTING: University hospitals. PATIENTS: Ten patients with AILD and cutaneous involvement. MAIN OUTCOME MEASURE: The T-cell receptor-gamma (TCRG)gene rearrangement was studied with the use of polymerase chain reaction and denaturing gradient gel electrophoresis in blood, nodal, and skin samples. Skin and nodal samples were investigated also for the presence of Epstein-Barr virus (EBV) RNA by in situ hybridization. RESULTS: A transient morbilliform eruption of the trunk was seen most often. Other cutaneous features were infiltrated plaques and purpuric or urticarial lesions. A clonal TCRG gene rearrangement was detected in 7 skin samples, corresponding to a maculopapular eruption with a histological pattern of nonspecific mild lymphoid dermal infiltrate in 6 patients, and to erythematous plaques with histological findings of typical cutaneous lymphoma in 1 patient. In the 5 patients in whom a TCRG gene rearrangement was evidenced in skin and lymph node samples, identical clones were detected in both. Five patients died by the end of the study, with a mean survival of 33.2 months. Four of these 5 patients had a clonal infiltrate in skin and lymph nodes. The EBV RNA was detected in only 1 of 10 skin biopsy specimens and in 5 of 8 lymph nodes tested. CONCLUSIONS: Cutaneous involvement is often related to a clonal T-cell proliferation in AILD, even when clinical and histological features are nonspecific. Cutaneous infiltrate seems to be clonally related to the nodal T-cell proliferation. The role of EBV infection in skin lesions was not evidenced.

Adult↗

Automated keratoconus detection using the EyeSys videokeratoscope.

PURPOSE: To evaluate the effectiveness of indices derived from the EyeSys System 2000 in detecting keratoconic corneas. SETTING: Department of Ophthalmology, Hôpital Saint Antoine, Paris VI University, Paris, France. METHODS: Topographies of 208 corneas were evaluated. The corneas were from 8 groups of patients classified by the following diagnoses: normal, regular astigmatism, cataract, radial keratotomy, photorefractive keratectomy, myopic keratomileusis, penetrating keratoplasty (PKP), and keratoconus. Nine statistical indices derived from EyeSys data, 2 Holladay Diagnosis Summary indices (coefficient of uniformity and coefficient of asphericity [Asph]), and our refractive power symmetry index were studied. A training set of 104 corneas was used to determine the most efficient threshold value of each index based on sensitivity and specificity curves. Decision trees combining 2 indices were generated. Sensitivity and specificity were calculated in a validation set composed of the remaining 104 corneas. RESULTS: Based on the results of the training set, the optimum indices were SDSD (standard deviation of the standard deviations of the radii of curvature of each ring) and Asph. In the validation set, the decision tree using these indices featured 88.5% sensitivity and 94.9% specificity; the 4 false-positive cases were in corneas in the PKP group of patients. CONCLUSIONS: Clinically apparent keratoconus can be detected among normal corneas and irregular corneal shape patterns using the EyeSys System 2000 data and a decision tree combining 2 indices.

Astigmatism↗

Skin tests and cutaneous anergy in children with ocular allergy.

PURPOSE: To evaluate skin tests with clinical ocular allergy and to compare cutaneous hypersensitivity and seasonal allergic conjunctivitis in children. CASE-REPORT: A 10-year-old girl presented a typical seasonal allergic conjunctivitis, never treated and the onset occurred one year before. She was skin tested for the allergy. Complete blood tests were also performed. An ocular treatment was given: olopatadine over 45 days. RESULTS: She showed a complete cutaneous anergy including histamine and codeine controls. Radioallergosorbent tests (RAST) found numerous great positivity to different allergens. Within 30 days under ocular treatment, she recovered completely from symptoms and clinical signs. CONCLUSION: Clinical typical seasonal ocular allergy in children with cutaneous anergy should be explored further or at least treated. Cutaneous hypersensitivity should be evaluated more precisely with a larger study comparing results in general allergy and in ocular allergy where the anergy seems to be more frequent.

Child↗

Salmonella enterica serovar typhimurium waaP mutants show increased susceptibility to polymyxin and loss of virulence In vivo.

In Escherichia coli, the waaP (rfaP) gene product was recently shown to be responsible for phosphorylation of the first heptose residue of the lipopolysaccharide (LPS) inner core region. WaaP was also shown to be necessary for the formation of a stable outer membrane. These earlier studies were performed with an avirulent rough strain of E. coli (to facilitate the structural chemistry required to properly define waaP function); therefore, we undertook the creation of a waaP mutant of Salmonella enterica serovar Typhimurium to assess the contribution of WaaP and LPS core phosphorylation to the biology of an intracellular pathogen. The S. enterica waaP mutant described here is the first to be both genetically and structurally characterized, and its creation refutes an earlier claim that waaP mutations in S. enterica must be leaky to maintain viability. The mutant was shown to exhibit characteristics of the deep-rough phenotype, despite its ability to produce a full-length core capped with O antigen. Further, phosphoryl modifications in the LPS core region were shown to be required for resistance to polycationic antimicrobials. The waaP mutant was significantly more sensitive to polymyxin in both wild-type and polymyxin-resistant backgrounds, despite the decreased negative charge of the mutant LPSs. In addition, the waaP mutation was shown to cause a complete loss of virulence in mouse infection models. Taken together, these data indicate that WaaP is a potential target for the development of novel therapeutic agents.

Animals↗

[Congenital corneal anesthesia in children: diagnostic and therapeutic problems].

Congenital corneal anesthesia (CCA) is an uncommon condition difficult to diagnose. We report the case of a 9-month-old girl who presented bilateral congenital corneal anesthesia. The child had a corneal ulcer which had been unresponsive to adapted local treatment. Self-inflicted corneal injuries were present. Local treatment and arm splints led to quick healing. CCA occurs either alone or in association with neurological diseases (familial dysautonomia) or systemic congenital abnormalities (Goldenhar Gorlin syndrome). It is important to search for corneal anesthesia in children with chronic ulcerations of the cornea and self-inflicted injuries. Early diagnosis is important due to the risk for the visual prognosis. Short and longterm prevention of self-inflicted corneal injuries should be associated with a local treatment to assure rapid healing and a relapse free outcome.

Corneal Diseases↗

[Acute closure-angle glaucoma after treatment with ipratropium bromide and salbutamol aerosols].

We report a case of acute angle-closure glaucoma in a patient treated with bronchodilator nebulization. An 82-year-old man with chronic obstructive bronchopathy was treated for acute respiratory decompensation with salbutamol and ipratropium bromide aerosols. Twenty-four hours after beginning the treatment, the patient developed acute angle-closure glaucoma which resolved rapidly with appropriate treatment. The case emphasizes the importance of precautionary measures (waterproof glasses and inhalation masks). In addition patients with a high risk of angle-closure glaucoma should be detected prior to prescribing bronchodilating aerosols.

Acute Disease↗

Corneal endothelial cell apoptosis in patients with Fuchs' dystrophy.

PURPOSE: To investigate whether apoptosis plays a notable role in degeneration of corneal endothelial cells in patients with Fuchs' dystrophy. METHODS: Forty-seven corneal buttons from 41 patients with Fuchs' dystrophy were studied. Nucleus labeling, transmission electron microscopy (TEM), and TdT-dUTP terminal nick-end labeling (TUNEL) were used to detect apoptosis. TEM and TUNEL were performed on sections of all 47 corneal buttons, and nucleus labeling was performed on the last 10 corneas. Seven human donor corneas, two corneal buttons from two patients with keratoconus, and one corneal button from a patient with interstitial keratitis were used as negative controls for detection of apoptotic endothelial cells. Negative controls were studied by means of nucleus labeling, TUNEL, and TEM. RESULTS: In the nucleus labeling assay, the average percentage of apoptotic endothelial cells was 2.65% in the Fuchs' dystrophy group (n = 10) and 0.23% in the control group (n = 10; P = 0.0003). In the TUNEL assay, labeling of some endothelial cells was observed on 42 of 47 corneas in the Fuchs' dystrophy group, whereas it was absent on most specimens of the control group. In TEM, most endothelial cell nuclei had a normal appearance, and apoptotic endothelial cells featuring condensed nucleus and decreased cell size could be observed exceptionally. Some apoptotic cells were found in the basal epithelial cell layer by means of nucleus labeling, TUNEL, and TEM in the Fuchs' dystrophy group but not in the control group. CONCLUSIONS: This study suggests that apoptosis plays an important role in endothelial cell degeneration in Fuchs' dystrophy. Because of a lack of conclusive evidence of increased endothelial apoptosis by TEM, further studies are needed to ascertain this finding.

Aged↗