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Results for “Axial elongation”

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PubMed2026

A Comprehensive Assessment of the Shared Genetic Architecture between Myopia and Open-Angle Glaucoma.

OBJECTIVE: Individuals with high myopia have an increased prevalence of open-angle glaucoma (OAG). We aim to clarify the possibly shared genetic architecture of myopia and OAG, in particular in high myopes with myopic macular degeneration (MMD), where OAG screening is highly challenging. DESIGN: Individual participant data meta-analysis of one-sample Mendelian randomization analyses and pleiotropic analysis under a composite null hypothesis. PARTICIPANTS: A total of 34 825 participants from 6 population-based cohort studies and 1 high myopia case-control study, including 708 OAG and 1953 high-myopia cases. METHODS: First, we calculated and validated genetic risk scores (GRSs) for OAG and myopia in each cohort. We subsequently meta-analyzed linear and logistic regression models for the association of a myopia GRS with OAG, intraocular pressure (IOP), and vertical cup-to-disc ratio (VCDR), and the association of an OAG-GRS with high myopia, axial length, and spherical equivalent. We stratified the analysis of OAG in different stages of axial elongation, and in high myopes with or without MMD. Pleiotropic analysis under a composite null hypothesis was applied to genome-wide association study summary statistics. MAIN OUTCOME MEASURES: Odds ratio (OR) of OAG and high myopia, and mean difference in IOP, VCDR, axial length, and spherical equivalent. RESULTS: One standard deviation (SD) increase in myopia GRS was associated with an OR (95% CI) of 1.18 (1.09, 1.28) for OAG, a beta (95% CI) of 0.04 (0.00, 0.08) mmHg in IOP, and of 0.005 (0.003, 0.007) in VCDR. The OAG-GRS was not significantly associated with high myopia compared to emmetropes, but a 1 SD increase was associated with a beta (95% CI) of 0.05 (0.01, 0.08) mm in axial length and of -0.05 (-0.10, -0.00) diopters in spherical equivalent. One SD increase in OAG-GRS had a substantially larger effect on OAG in high myopes with MMD, with an OR (95% CI) of 3.83 (1.89, 7.78) compared to 1.55 (1.24, 1.94) in emmetropes. Finally, we identified 95 independent pleiotropic single-nucleotide polymorphisms (SNPs). CONCLUSIONS: There is strong evidence for pleiotropy between myopia and OAG. Further research into the biological mechanisms of the identified pleiotropic SNPs is needed. An OAG-GRS might help to clinically estimate OAG risk, in particular in individuals with MMD. FINANCIAL DISCLOSURES: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Axial length↗

PubMed1979

Physiologic vs pathologic myopia: genetics vs environment.

Physiologic myopia occurs as the result of a correlation failure of refraction components in the normal eye. Pathologic myopia is caused by excessive axial elongation that primarily involves the ora-equatorial area and the posterior pole. Peripheral fundus changes and posterior staphyloma formation are ophthalmoscopic evidences of this process. Heredity is the basic determinant of ocular refraction, but numerous agents produce both temporary and permanent myopias.

Animals↗

PubMed2026

Increased PRSS56 expression is a causal factor and therapeutic target for human axial high myopia.

High myopia (HM), characterized by significant ocular axial length elongation, affects hundreds of millions of people and is often inherited, particularly in cases that develop during childhood or adolescence. Although numerous myopia loci (MYP) have been identified, most causative genes remain undefined. Here, we analyzed two large HM pedigrees and refined the critical region through haplotype linkage analysis to a 3.9-Mb interval on 2q37.1, which was previously reported as MYP12 with an unknown pathogenic gene. Whole-genome sequencing identified the noncoding promoter variants c.-187G>T and c.-187G>C in PRSS56, encoding a trypsin-like serine protease, which exclusively co-segregated with all affected members in both pedigrees. Compared with matched controls, increased PRSS56 expression was observed in both patient-derived iPSCs carrying c.-187G>T and knock-in mice (c.-155G>T, corresponding to human c.-187G>T) that faithfully recapitulate myopia phenotypes. Noncoding PRSS56 variants promote self-expression via enhanced binding to the transcription factor EGR1, as confirmed by dual-luciferase assays. Notably, we demonstrated that higher PRSS56 levels directly increase ocular axial length in a dose- and activity-dependent manner in multiple transgenic mouse models. Guinea pig myopia models consistently exhibited high Prss56 expression, and short-wave light exposure reduced Prss56 mRNA levels and attenuated further axial elongation. Mechanistically, higher PRSS56 expression was associated with reduced abundance of myosin-4 in the sclera and with molecular signatures of scleral remodeling, which were in turn correlated with axial elongation. In conclusion, our findings provide strong genetic and functional evidence for the pathogenic role of noncoding PRSS56 variants in HM and highlight PRSS56 as a promising therapeutic target for juvenile HM.

Humans↗

PubMed1979

Ultrasonographic study on changes in axial eye dimensions after encircling procedure in retinal detachment surgery.

The pre- and postoperative results of ultrasonographic measurements on the axial ocular components in 10 phakic eyes with retinal detachment treated with encircling silicone rubber band are presented. A significant increase (P less than 0.001) in axial eye length from 0.62 to 1.24 mm (average: 0.98 mm) was found. The elongation of the eye was caused by a corresponding increase in the length of the vitreous cavity. No significant changes were found in the anterior segment of the eyes. These data demonstrate that the postoperative refractive change in a myopic direction, which an encircling procedure with moderate indentation often produces, is caused by an axial elongation of the eye.

Adolescent↗

PubMed1979

Structure of cross-linked rabbit muscle phosphofructokinase in solution.

Cross-linked rabbit muscle phosphofructokinase in the active tetrameric and octameric state was studied in solution by hydrodynamic methods and small angle x-ray scattering techniques. The translational diffusion coefficients were determined by means of inelastic light scattering and were found to be 3.60 (+/- 0.02) x 10(-7) cm2 . s-1 for the tetramer and 2.54 (+/- 0.15) x 10(-7) cm2 . s-1 for the octamer. From small angle x-ray scattering measurements the radius of gyration, the specific inner surface area, and the volume were determined for both enzyme forms, revealing that the octameric cross-linked form is approximately spherical, with a diameter of 120.0 A, whereas the tetrameric form is asymmetric having an axial ratio of 2. By comparison of the scattering curves with triaxial geometric bodies which are equivalent in scattering, the tetrameric enzyme is described as a rectangular prism, with overall dimensions of A = 131.0 A, B = 131.0 A, and C = 65.0 A, and the octameric form as that of a cube with A = B = C = 120.0 A. The shape of the protomer, having a radius of gyration of 24.8 A, in the tetramer and octamer is similar to that for the native tetramer at pH 10 in the presence of 5 mM fructose 6-phosphate or 15 mM fructose 1,6-bis-phosphate. From the different shapes of the scattering curves of the native phosphofructokinase at pH 7.5 in the presence of 15 mM ATP and of the cross-linked tetramer or octamer, it can be inferred that the shapes of the protomers are different: in the presence of ATP the protomers are elongated, having an axial ratio of 1.8 to 2.0; the cross-linked state reveals a spherical protomer of radius 33.0 A, similar to that of the native enzyme at pH 7.5 in the presence of fructose 6-phosphate or fructose 1,6-bisphosphate.

Animals↗

PubMed1976

Structure and assembly of filamentous bacterial viruses.

Filamentous bacterial viruses are flexible nucleoprotein rods, about 6 nm in diameter by 1000-2000 nm in length (depending on the virus strain). A protein shell encloses a central core of single-stranded circular DNA. The coat protein subunits forming the shell are largely alpha-helix, elongated in an axial direction, and also sloping radially, so as to overlap each other and give an arrangement of subunits reminiscent of scales on a fish. This arrangement of alpha-helices is rather like some models of myosin filaments. An early step in assembly of the virion is the formation of a complex between the viral DNA and an intracellular packaging protein that is not found in completed virions. Newly synthesized coat protein becomes associated with the plasma membrane of the cell. During the final steps of assembly, the packaging protein is displaced from the DNA and replaced by coat protein as the virion passes out through the plasma membrane of the host cell.

Bacteriophages↗

PubMed1977

Involvement of 30S ribosomal protein S1 in poly(U)-directed polyphenylalanine synthesis.

The effect of 30S ribosomal protein S1 on poly(U)-directed polyphenylalanine synthesis was studied using a highly purified cell-free system which was devoid of endogenous S1. The system consisted of homogeneous preparations of EF-Tu, EF-Ts, and EF-G, and 70S ribosomes from which protein S1 had been removed by poly(U)-cellulose column chromatography. It was found that protein S1 was indispensable for translation of poly(U) by an S1-depleted system at low concentrations of poly(U). On the other hand, at higher concentrations of poly(U), a considerable amount of polyphenylalanine was synthesized in the absence of added S1. The stimulatory effect of S1 was observed at all Mg2+ concentrations examined but was most pronounced at 10 mM Mg2+. Some physicochemical properties of the protein were also studied. It was demonstrated that the protein has an elongated shape with an axial ratio of approximately 8.5.

Escherichia coli↗

PubMed1975

Macronuclear differentiation during oral regeneration in Stentor coeruleus.

The moniliform macronucleus of Stentor coeruleus coalesces and renodulates during division, reorganization and regeneration. These nuclear events are spatially and temporally synchronized with oral primordium development occurring at stages six and seven of membranellar morphogenesis. Coalesced, elongating and early renodulating macronuclei at states six and seven contained microtubules within double membrane-bound channels, passing through the nucleus parallel to the long axis. The number of microtubules per channel varied between 4 and 23. Microtubules were also found in the perinuclear cytoplasm at these stages, forming a loose network around the nucleus. The microtubules and channels are absent in control cells and macronuclei of regenerating cells prior to stage six. These transient microtubules and channels appearing in late stage six and stage seven may provide the axial plane on which elongation of the macronucleus proceeds.

Animals↗

PubMed1979

Studies on 30S ribosomal protein S1 from E. coli. I. Purification and physicochemical properties.

1. The distribution of ribosomal protein S1 in subcellular fractions of E. coli was determined by radioimmunoassay. It was found that about 70%, 20% and 10% of protein S1 were present in the high salt (1.0 M NH4Cl)-washed ribosomes, the ribosomal wash and the S100 fraction, respectively. 2. Protein S1 was purified from unwashed ribosomes by an improved procedure which included: (i) extraction of protein S1 from unwashed ribosomes with 1.2 M LiCl and 1.0 M NH4Cl, (ii) ammonium sulfate fractionation, (iii) two successive column chromatographies on DEAE-Sephadex, and (iv) hydroxylapatite column chromatography. Purified protein S1 was homogeneous in polyacrylamide gel electrophoresis under native and denatured conditions. 3. The molecular weights determined by sedimentation equilibrium and by SDS-polyacrylamide gel electrophoresis were 83,000 and 70,000 respectively. The sedimentation coefficient was estimated as 3.0S by glycerol gradient centrifugation. The stokes radius determined by Sephadex G-200 gel filtration was 45 A. From these data, the frictional ratio of protein S1 was calculated to be 1.65, assuming the molecular weight and partial specific volume to be 70,000 and 0.736, respectively. Protein S1 had an elongated shape with an axial ratio of approximately 8.5. 4. Protein S1 contained 2 residues of half-cystine and about 10 residues of tryptophan. From CD measurements, the contents of alpha-helix and beta-structure were estimated to be 32 and 27%, respectively. 5. As reported by Kolb et al. (1977) (Proc. Natl. Acad. Sci. U.S. 74, 2379-2383), and Draper et al. (1977) (Proc. Natl. Acad. Sci. U.S. 74, 4786-4790), the intrinsic fluorescence of protein S1 was markedly quenched on interaction with poly(U). The maximal quenching was observed when 30 mol of poly(U) (as UMP residues) was added to one mol of the protein.

Amino Acids↗

PubMed1979

Increase in axial length of the macaque monkey eye after corneal opacification.

The cornea of one eye was opacified in two young macaque monkeys by multiple stromal injections of a suspension of polystyrene particles (latex). Ultrasound measurements showed that the eye with opaque cornea grew at a faster rate, so that after 1 year it was more than 1 mm longer than the normal eye. This difference in axial length was due to elongation of the posterior segment, since lens thickness, depth of anterior chamber, and corneal curvature were identical in both eyes. At histological examination, no pathological changes were observed in the anterior segment of the latex-injected eye except for a scant vascularization of the corneal opacity. The result of this experiment demonstrates that opacification of the corneal has effects on axial length similar to, although less marked than, those on lid fusion and therefore supports our previous conclusion that the myopia caused by lid fusion is triggered by the abnormal visual impact and involves central visual pathways.

Animals↗

PubMed2025

Intraocular pressure is a promising target for myopia control.

BACKGROUND: Myopia presents a noteworthy global health concern, urging exploration of innovative treatments. The role of intraocular pressure (IOP) in regulating the progression of myopia has been controversial. METHODS: To investigate the impact of reducing IOP to varying extents on myopia progression, three groups receiving distinct IOP-lowering medications (Brinzolamide, Latanoprost, and a combination of Brinzolamide and Latanoprost) were designed in a form-deprived myopic guinea pig model. Additionally, proteomics analyses were conducted to identify differentially expressed proteins in the sclera. RESULTS: Based on 24-h and 4-week IOP monitoring, the group receiving both Brinzolamide and Latanoprost exhibited the greatest magnitude of IOP reduction and the most significant inhibition of axial length (AL) growth. Moreover, the administration of IOP-lowering medications increased choroidal thickness and induced alterations in the structure of scleral collagen fibrils. Notably, scleral proteomics revealed remodeling processes associated with key mechanisms, including proteolysis, fibrinolysis, and metal ion binding. CONCLUSIONS: Our findings highlight that pressure-dependent scleral remodeling contributes to the deceleration of AL elongation. These results underscore the efficacy of IOP reduction in mitigating the progression of myopia, providing a promising alternative strategy for myopia management.

Myopia↗

PubMed1976

[Conformation of the fibrinogen molecule in solution: dynamic light scattering spectroscopy].

Human fibrinogen solutions were prepared either by filtration of ultracentrifugation. The sedimentation coefficient was S20,W = 7,9 S. The translational and the rotational diffusion coefficient DT and DR and the fraction of oligomers were determined using light beating spectroscopy. DT20,W was (2.03 +/- 1%) 10(-7)-cm2-sec-1, DR120,W = 40 000 +/- 10%-sec-1. The sedimentation coefficient and DT were strongly dependent on concentration. For pH values between 6.5 and 9.0, the diffusion coefficient DT at ionic strength greater than 0.2 was constant. The diffusion coefficient as measured by nanosecond fluorescence depolarization was DR//20,W = 1.6 x 10(6) sec-1. At a fibrinogen concentration of 2 mg/ml, these hydrodynamic data are compatible with an elongated molecule of 450 A length and an axial ratio of about 1:7.

Fibrinogen↗

PubMed1978

Effect of dark-rearing on experimental myopia in monkeys.

When lids are surgically fused in rhesus monkeys before eye growth is completed, a high degree of myopia develops, which is caused by an elongation of the eye globe. The present study shows that in monkeys raised in the dark after monocular lid fusion, refraction and axial length were normal in both the closed and the open eye. Myopia, however, readily developed and the eye elongated when a monkey raised in the dark was transferred to illuminated quarters. These findings indicate that visual stimulation through the translucent lids was necessary for the development of this experimental ametropia.

Animals↗

PubMed1976

[The use of A-scan echography in the clinical diagnoses of persistent hyperplastic primary vitreous (PHPV) (AUTHOR'S TRANSL)].

In 15 eyes with PHPV (3 suspected cases) patterns of rudimentary hyaloid vessels were found by A-scan echography in 9 cases all under 7 years of age; although these vessels were seen ophthalmoscopically in only 1 case. This ultrasonographic finding appears to add an important contribution to the clinical diagnosis of PHPV, when the monolateral cataract is so dense as to observe other signs (elongated ciliary processes, retrolental fibrovascular tissue). It could also be demonstrated that the axial diameter of the lens remains smaller than that of the partner eye even when the cataract is intumescent with fattening of the anterior chamber. Contrary to our expectations, the axial length of the bulbus was increased in one third of the cases; while a relative microcornea was absent only in 2 eyes!

Adolescent↗

PubMed1977

Ultrastructural studies on the differentiation of spermatids in the domestic fowl.

Four phases of spermatid maturation are recognized on the basis of nuclear morphology. The formation of the acrosome, perforatorium and axial filament complex are described in relation to these phases. The functional significance of the microtubular systems in nuclear elongation and spermatid curvature are discussed. A membranous structure, hitherto unidentified, and referred to in this study as the 'membrane body' is compared with the chromatoid body. Morphological evidence suggests that this structure, together with the annulate lamellae, removes excessive nuclear material.

Animals↗

PubMed1978

Radiology of the jugular tubercles.

The jugular tubercles are two small protuberances that arise from the inferolateral margins of the clivus and project posterosuperiorly over the hypoglossal canals. The jugular tubercles are clearly seen on routine anteroposterior temporal bone tomograms and may be identified on axial or coronat CT scans. Varying widely in size and configuration, these structures are usually somewhat ovoid but can be elongated, gently squared, or asymmetric. Despite this variation in size and appearance, no normal instances were found in which the superior surface of the jugular tubercles appeared either flattened or concave. The radiology of the normal and pathologic jugular tubercle is described. The material outlined was derived from radiographic studies of both dried skulls and a variety of normal and abnormal clinical cases.

Adult↗

PubMed1978

Unusual features of the nuclear envelope in human spermatogenic cells.

Different types of human germ cells show unusual features of the nuclear envelope. Spermatogonial nuclei demonstrate two kinds of modifications. The first one is a series of intranuclear flattened cisterns, parallel to each other and to the inner aspect of the nuclear envelope. The second one is a nuclear envelope protrusion into the cytoplasm occupied by a double membrane-limited vesicle. Pores are found on the membrane of the vesicle facing the interior of the nucleus. In spermatocytes the nuclear pores are concentrated over certain areas and completely absent from others. In the regions where they are absent a single cytoplasmic cistern of rough endoplasmic reticulum is closely apposed to the outer membrane of the nuclear envelope. Early modifications of the nuclear surface appear in spermatids before the attachment of the acrosomic vesicle and may indicate an active role of the nuclear envelope in the morphogenesis of the acrosome. In round spermatids nuclear pores are absent from the area which is first related to the Golgi and later covered by the acrosomal cap. Single or multiple layers of cytoplasmic annulate lamellae are closely associated with the nuclear envelope over the pore rich areas. Frequently there are intranuclear accumulations of dense material adjacent to the annulate lamellae-nuclear pore complex. The chromatoid body is usually present on the cytoplasmic side of this complex. In the elongating spermatids most annulate lamellae are free in the cytoplasm, often in relation with Golgi and chromatoid body remnants near the axial filament. Few stacks of annulate lamellae are noted adjacent to the pore rich nuclear regions. It is suggested that the described modifications are related to an active nuclear-cytoplasmic interaction.

Adult↗

PubMedDate not supplied

Spontaneous thrombosis of an arteriovenous malformation.

Extensive thrombosis of a cerebral arteriovenous malformation, not associated with clinically recognizable hemorrhage, appears to be exceedingly rare. Angiographic and operative verification of such an occurrence is described in a 4-year-old child. Computed axial tomographic and ultrasonographic findings are discussed. It is proposed that thrombosis of the anomaly occurred as a result of intravascular turbulence, promoted by progressive elongation and increasing tortuosity of the lesion.

Child, Preschool↗