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Autologous chondrocyte implantation: superior biologic properties of hyaline cartilage repairs.

Information regarding the quality of autologous chondrocyte implantation repair is needed to determine whether the current autologous chondrocyte implantation surgical technology and the subsequent biologic repair processes are capable of reliably forming durable hyaline or hyaline-like cartilage in vivo. We report and analyze the properties and qualities of autologous chondrocyte implantation repairs. We evaluated 66 autologous chondrocyte implantation repairs in 57 patients, 55 of whom had histology, indentometry, and International Cartilage Repair Society repair scoring at reoperation for mechanical symptoms or pain. International Knee Documentation Committee scores were used to address clinical outcome. Maximum stiffness, normalized stiffness, and International Cartilage Repair Society repair scoring were higher for hyaline articular cartilage repairs compared with fibrocartilage, with no difference in clinical outcome. Reoperations revealed 32 macroscopically abnormal repairs (Group B) and 23 knees with normal-looking repairs in which symptoms leading to arthroscopy were accounted for by other joint disorders (Group A). In Group A, 65% of repairs were either hyaline or hyaline-like cartilage compared with 28% in Group B. Autologous chondrocyte repairs composed of fibrocartilage showed more morphologic abnormalities and became symptomatic earlier than hyaline or hyaline-like cartilage repairs. The hyaline articular cartilage repairs had biomechanical properties comparable to surrounding cartilage and superior to those associated with fibrocartilage repairs.

Adolescent↗

Ultrastructure of alcoholic hyalin and fate of the affected hepatocytes.

In liver biopsy specimens, foci of satellitosis, i.e., foci of alcoholic hyalin containing hepatocytes surrounded by accumulated leukocytes, were studied by means of electron-microscopic investigation. Within satellitosis hepatocytes, the same morphologic variants of alcoholic hyalin were observed as formerly described in nonsatellitosis liver cells: (1) clusters of randomly oriented smooth filaments of homogenous electron density, (2) bundles of filaments aligned in parallel arrays and exhibiting irregular densities and indistinct boundaries, and (3) masses of a strongly osmiophilic amorphous material, presumably lipidic in nature. The individual hyalin body was composed of one, two, or all three components in varying proportions; an uptake by cytosegresomes was never observed. The leukocytes of satellitosis foci, mostly polymorphonuclear ones without obvious alterations, had close contact to the central hepatocytes, and sometimes covered large holes in the hepatocellular plasma membrane. In other cases, hepatocytes and neutrophils were both destroyed and the hyalin bodies were found unaltered within the sinusoids. It is suggested that alcoholic hyalin represents an inert proteinaceous storage material, deposited at the site of synthesis which in the course of time becomes superimposed by a lipid component. In cases of alcohol-induced hepatocellular lesions, those hepatocytes which produce hyalin bodies may have a special metabolic sensitivity to alcohol which on the one hand may result in hyalin synthesis and accumulation and on the other hand may, under special conditions, lead to plasma membrane destruction with secondary satellitosis formation.

Alcoholism↗

Occurrence of hyaline droplets in renal biopsy specimens: an ultrastructural study.

Hyaline droplets are apical cytoplasmic vesicles containing an accumulation of electron-dense amorphous materials surrounded by a unit membrane. Hyaline droplets may originate from apical vesicles after conversion to osmotic vesicles and loss of internally lined glycocalyx. They are found in the proximal tubular epithelium in biopsies from patients with renal diseases; however, their biological importance is not well understood. We reviewed ultrastructural pathology records of 140 renal biopsy patients to determine the occurrence and relevance of hyaline droplets. Of the cases, 14 (10%) showed the presence of hyaline droplets in proximal tubular epithelium. The distribution of cases were 8 of the 19 (42%) with minimal change nephritic syndrome, 2 of the 37 (5%) with IgA nephropathy, 2 of the 4 (50%) with membranous glomerulonephropathy, 1 of the 4 (25%) with tubulointerstitial nephritis, and 1 of the 1 (100%) with acute renal failure. The droplets were frequently found in male patients (86%), never in children, and were mostly associated with tubular necrosis (8 of 14 cases; 56%). Many hyaline droplets were observed in the cytoplasm of necrotic proximal tubular epithelial cells, and even when tubular necrosis was not evident, the proximal tubular epithelial cells containing hyaline droplets showed degenerated microvilli and decreased basal interdigitations. These results suggest that hyaline droplets could be one marker of renal tubular necrosis and a sign of functional disorder of protein reabsorption by degenerating proximal tubular epithelium.

Adult↗

Migration of hyaline cells into the chick basilar papilla during severe noise damage.

Severe acoustic damage in the chick cochlea causes a destruction of both hair cells and supporting cells in a localized area on the basilar papilla. In this region, the sensory cells are replaced by a layer of flattened epithelial cells. We have employed scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) to examine the structure and cytoskeletal changes involved in this process. Immunocytochemical staining for actin indicates that the flattened cells are derived from the hyaline cells normally located along the inferior edge of the basilar papilla. In control cochleae the hyaline cells contain dense bundles of actin filaments that anchor into the basal surface of the cells. The hyaline cells appear to redistribute into the severely damaged region by extending the actin bundles at their basal surfaces. Moreover, the efferent nerves that normally form a network among the hyaline cells move into the severely damaged area along with the hyaline cells. In moderately damaged cochleae, where only hair cells are lost, the hyaline cells do not spread into the damaged region. The functional role of this hyaline cell migration is unknown, but it may be involved in maintenance or repair of the severely damaged cochlea.

Acoustic Stimulation↗

Hyaline cell-rich chondroid syringoma: case report and review of the literature.

Hyaline cell-rich chondroid syringoma (HCRCS) is a rare benign cutaneous neoplasm composed of cells with eosinophilic hyaline cytoplasm and plasmacytoid features, the origin of which remains elusive. To the best of our knowledge, only eight cases of this entity have been reported so far, and none of them was submitted to a large panel of myoepithelial markers. We report on a case of a previously healthy 29-year-old male patient who presented with a slowly enlarging flesh-colored nodule on the palmar aspect of the tenar region of his left hand, measuring 2 cm in maximum diameter. The nodule was "shelled-out" and submitted to light microscopy, immunohistochemistry, and ultrastructural examination. Histopathologic analysis disclosed a lobulated neoplasm composed of hyaline cells with plasmacytoid features showing ovoid nuclei, with occasional invaginations, finely granular chromatin, and discrete nucleoli; the cytoplasm was deeply eosinophilic with occasional dot-shaped paranuclear hyaline inclusions. On immunohistochemical evaluation, hyaline cells were strongly and diffusely positive for S-100 protein, vimentin, pan (CAM 5.2) and high molecular weight (34betaE12) cytokeratins; these cells were focally positive for GFAP, maspin, neuron-specific enolase, and cytokeratin 14. Alpha-smooth muscle actin, epithelial membrane antigen, carcinoembryonic antigen, collagen IV, Gp100 (HMB-45), and p63 were negative in neoplastic hyaline cells. Ultrastructural analysis disclosed cells with ovoid nuclei showing occasional invaginations and nuclear pockets; the cytoplasm was rich in meshworks of non-bundling intermediate filaments and a variable amount of rough endoplasmic reticulum cisternae. Based on our findings and those previously reported, hyaline cells of HCRCS might posses an aberrant myoepithelial differentiation. Most importantly, pathologists need to be aware of the histologic and immunohistochemical features of HCRCS to avoid a misdiagnosis of highly malignant neoplams, such as malignant melanoma and extra-skeletal myxoid chondrosarcoma.

Adenoma, Pleomorphic↗

Cell membrane and cytoplasmic staining for MIB-1 in hyalinizing trabecular adenoma of the thyroid gland.

The monoclonal MIB-1 antibody reacts with the nuclei of cells in the late G1, S, G2, and M phases of the cell cycle. Previously, we found two cases of hyalinizing trabecular adenoma that showed cell membrane and cytoplasmic immunopositivity for the antibody. The purpose of this investigation was to confirm this exceptional reactive pattern of MIB-1 in hyalinizing trabecular adenoma. For the study, we collected 13 additional hyalinizing trabecular adenomas and stained a total of 15 tumors using MIB-1 antibody. Ten cases of papillary thyroid carcinoma were studied similarly. All hyalinizing trabecular adenomas showed strong positivity for the antibody in 90% or more of the tumor cells, localized especially to the cell membrane and also to the cytoplasm. There was no cell membrane or cytoplasmic MIB-1 positivity among the 10 papillary carcinomas. Luminal border of normal extratumoral thyroid follicles rarely showed faint immunopositivity. Our findings indicate that strong cell membrane and cytoplasmic immunoreactivity for MIB-1 is a characteristic of the hyalinizing trabecular adenoma. Staining for MIB-1 will be useful in differentiating hyalinizing trabecular adenoma from papillary carcinoma, which shares a number of cytologic and histologic findings with hyalinizing trabecular adenoma.

Adenoma↗

Histologic and statistical studies on hyalin bodies in the human endolymphatic sac.

Hyalin bodies are amorphous, eosinophilic masses that protrude from the subepithelial connective tissue into the lumen of the endolymphatic sac. In this study, hyalin bodies were analyzed in two groups of temporal bones: normal bones and bones with cochlear otosclerosis. The results revealed that bones with cochlear otosclerosis had significantly more and larger hyalin bodies that did normal bones. In addition, the hyalin bodies in cochlear otosclerosis were denser and associated with more edema and loose connective tissue in the surrounding areas. Foamy macrophages, concentric calcific structures, and bony ingrowth were frequent features of the hyalin bodies in the cochlear otosclerosis. Our current hypothesis is that these hyalin bodies are repository of membranous cellular debris phagocytized by the macrophages. If this is true, the hyalin bodies may further support the proposed resorptive and phagocytic functions of the endolymphatic sac and the enzymatic concept in cochlear otosclerosis.

Adolescent↗

Immunocytochemical identity of hepatocellular hyalin in alcoholic and non-alcoholic liver diseases.

Intracellular, eosinophilic, hyaline inclusions (alcoholic hyalin, Mallory bodies) are found in livers of patients with a number of hepatic disorders, although they are most common in alcoholic liver disease. Tissues from patients with primary biliary cirrhosis, jejunoileal bypass, hepatocellular carcinoma, Wilson's disease, and Indian childhood cirrhosis were all positive for hyalin by hematoxylin and eosin staining. Immunocytochemical labeling, using guinea-pig antiserum specific for alcoholic hyalin, was utilized to determine the extent of crossreactivity between hepatocellular hyalin in these various conditions. This antiserum bound to hyalin in fixed paraffin-embedded sections of all liver tissues studied as detected by indirect immunoperoxidase labeling. Binding to normal human liver, however, was restricted to light staining at the surface of hepatocytes. Preimmune guinea-pig serum did not bind to either normal liver or to the test tissues. Our results suggest that hyalin found found in a diverse group of liver conditions represents an immunologically related structure and that its formation may involve a common mechanism.

Adolescent↗

A HISTOLOGICAL STUDY OF HYALINE DEPOSITS IN LARYNGEAL, AURAL, AND NASAL POLYPS AND THEIR DIFFERENTIATION FROM AMYLOID.

Sections of hyalinized laryngeal polyps stained with haematoxylin and eosin or Congo red can easily be confused with localized amyloid of the larynx. Several histological methods were applied to 61 specimens containing hyaline deposits or hyalinized tissues which included 36 laryngeal polyps. The results were compared with seven cases of localized amyloidosis of the upper respiratory tract and four cases of secondary amyloidosis. The hyaline deposits gave a pattern of results which were different from amyloid. They showed no metachromasia, low affinity for Congo red, weak birefringence in an unstained state, no birefringence if stained with Congo red, weak or negative fluorescence if stained with Thioflavin T, low resistance to pepsin digestion, positive phosphotungstic acid haematoxylin staining areas, and a high affinity for the picric acid component of van Gieson stain. Hyalinized collagen closely resembles amyloid, but it can be excluded by a van Gieson stain. No evidence of amyloid formation was found in areas of hyaline deposits in the larynx. This supports the view that localized amyloidosis of the larynx and hyalinized laryngeal polyps are different pathological entities.

Amyloid↗

Selective metal ion binding at the calcium-binding sites of the sea urchin extraembryonic coat protein hyalin.

The interaction of metal ions with the sea urchin extraembryonic coat protein hyalin was investigated. Hyalin, immobilized on nitrocellulose membrane, bound Ca2+ and this interaction was disrupted by ruthenium red and selective metal ions. The divalent cations Cd2+ and Mn2+, when present at a concentration of 30 microM, displaced hyalin-bound Ca2+. In competition assays, 1 mM Cd2+ or 3 mM Mn2+ were effective competitors with Ca2+ for binding to hyalin. Cobalt, at a concentration of 30 microM, was unable to displace protein-bound Ca2+, but was effective in competition assays at a concentration of at least 10 mM. Magnesium and the monovalent cation Cs+ were unable to disrupt Ca2(+)-hyalin interaction. Interestingly, Cd2+, Mn2+, and Co2+ mimicked the biological effects of Ca2+ on the hyalin self-association reaction. These results clearly demonstrate that the Ca2(+)-binding sites on hyalin can selectively accommodate other divalent cations in a biologically active configuration.

Animals↗

[Immune complexes: mediators for the formation of inflammatory granulation tissue? Immunohistologic studies of the hyaline articular cartilage in chronic polyarthritis].

Previous reports describe the presence of immunoglobulins and complement components within rheumatoid articular cartilage, thereby suggesting an effect of immune complexes on the formation of pannus. This hypothesis is reinvestigated in this paper. As confirmed in our work, the superficial layer of rheumatoid hyaline cartilage may fulfill the immunohistological criteria for the presence of immune complexes. In osteoarthritis, however, a noninflammatory disease not mediated by immunologic mechanisms, similar results can be obtained. The presence of immune-proteins within hyaline cartilage therefore requires a cautious interpretation. Hyaline cartilage in rheumatoid arthritis is replaced by granulation tissue growing not only at its surface (pannus), but also in subchondral bone. We therefore also thoroughly investigated deep layers of hyaline cartilage in the vicinity of such subchondral tissue, but could not obtain any evidence for the presence of immune complexes therein. The growth of subchondral granulation tissue and the accumulation of PMN in the region of its junction with hyaline cartilage therefore appear to be independent of immune complexes within rheumatoid hyaline cartilage. It is suggested on the basis of these data that immune complexes possibly present in hyaline cartilage do not play an essential role in the formation of granulation tissue replacing cartilage in rheumatoid arthritis. It is, however, not entirely excluded that during advanced stages of rheumatic cartilage degradation immune complexes are formed within the matrix or carried into it from the extra-cartilaginous environment, and that they may then contribute to further cartilage destruction by enzyme release during phagocytic processes.

Antigen-Antibody Complex↗

Familial cardioneuromyopathy with hyaline masses and nemaline rods: a novel phenotype.

Two siblings (patients 1 and 2) had adult-onset muscle weakness that was greater distally than proximally, as well as respiratory insufficiency, cardiomyopathy, and cervical spine anomalies. Electromyography studies indicated myopathy and findings consistent with neuropathy in both. In the deltoid muscle of patient 1 and the anterior tibial muscle of patient 2, myriad type 1 fibers harbored large, irregularly polygonal, and mostly central hyaline masses, small vacuoles, and nemaline rods flanking the hyaline masses or congregated under the sarcolemma. The hyaline masses are intensely congophilic; react strongly for desmin, alphaB-crystallin, alpha1-antichymotrypsin, and ubiquitin and variably for gelsolin and dystrophin; and are devoid of alpha-actinin, nebulin, titin, and slow myosin. The presence of ubiquitin, gelsolin, and fragmented filaments, and the absence of nebulin, titin, alpha-actinin, and slow myosin in the hyaline masses, signal nonlysosomal protein degradation. Ultrastructurally, the hyaline masses are composed of intermediate-density amorphous material intermingled with fragmented filaments and irregularly branching, pleomorphic, highly electron-dense material, resembling the hyaline structures of myofibrillar myopathy. We conclude that the pathological process in this syndrome is one that induces destruction of myofibrillar components, resulting in aggregation of the degraded residues in hyaline masses, and causes replication of Z disks, resulting in formation of nemaline rods.

Age of Onset↗

d-Limonene induced hyaline droplet nephropathy in alpha 2u-globulin transgenic mice.

d-Limonene is a hyaline droplet inducing agent and produces nephrotoxicity in male rats when the 1,2-epoxide metabolite binds to alpha 2u-globulin. Mice, which do not synthesize alpha 2u-globulin, are resistant to hyaline droplet nephropathy. In this study, the ability of d-limonene to cause hyaline droplet nephropathy in a transgenic mouse engineered to express alpha 2u-globulin was evaluated. The C57BL/6-derived mice excreted 0.4 +/- 0.1 mg alpha 2u-globulin/day, or approximately 16 mg alpha 2u-globulin/kg body wt. This represents about 30% of the amount excreted by adult male rats (11.9 +/- 1.1 mg/day or approximately 48 mg/kg). Transgenic mice excreted less mouse urinary protein (9.3 +/- 1.2 mg/day) than normal mice (15.1 +/- 1.6 mg/day). Unlike normal male rats, untreated transgenic mice did not show significant spontaneous hyaline droplet formation. Liver microsomes from naive transgenic mice oxidized d-limonene to the cis- and transisomers of the 1,2-epoxide, and following oral treatment with [14C]d-limonene reversible binding of d-limonene equivalents to renal cytosolic proteins was observed. Furthermore, with d-limonene treatment, hyaline droplets were observed in the transgenic mouse kidneys. These droplets, however, were much smaller in size than those seen in d-limonene-treated male rats. The accumulation of alpha 2u-globulin in the kidneys of transgenic mice and normal male rats before and after d-limonene treatment was analyzed by Western blotting. These results indicated that alpha 2u-globulin was present in the kidneys of the control transgenic mice, despite the lack of spontaneous hyaline droplet formation. After d-limonene treatment, approximately a three-fold increase in alpha 2u-globulin in the transgenic mouse kidney was observed, a response similar in magnitude to that seen in d-limonene-treated male rats. These results indicate that expression of alpha 2u-globulin in a species that does not normally develop hyaline droplet nephropathy is necessary and sufficient to render that species sensitive to this renal toxicity.

Alpha-Globulins↗

Muscarinic receptors modulate intracellular Ca(2+) concentration in hyaline cells of the chicken basilar papilla.

Nonsensory hyaline cells border the sensory epithelium of the auditory end-organ (basilar papilla) in birds and reptiles. Their innervation by cochlear cholinergic efferent fibers and the presence of contractile proteins suggest that hyaline cells may actively regulate basilar membrane mechanics. The cholinergic pharmacology of hyaline cells was studied by measuring the intracellular calcium concentration ([Ca(2+)](i)) of fura-2-loaded cells in the chicken cochlea in vitro. Superfusion of the cholinergic agonist carbachol produced a dose-dependent increase in hyaline cell [Ca(2+)](i) (EC(50)=1.05 micromol l(-1)) and small responses in short hair cells. Calcium increases in hyaline cells were evoked by the muscarinic agonists oxotremorine (10 micromol l(-1)) and muscarine (100 micromol l(-1)) whereas nicotine (100 micromol l(-1), 200 micromol l(-1)) was without effect. Carbachol-evoked responses were blocked by the muscarinic antagonist atropine (>or=10(-13) mol l(-1)) and were unaffected by the nicotinic antagonists d-tubocurare (100 micromol l(-1), 1 mmol l(-1)) and hexamethonium (100 micromol l(-1)). Responses persisted in the absence of extracellular Ca(2+) and were abolished by thapsigargin (1 micromol l(-1)). These results indicate that the cholinergic-stimulated increase in hyaline cell [Ca(2+)](i) is due to a muscarinic-mediated release of Ca(2+) from intracellular stores. This is the first evidence that hyaline cells possess a muscarinic receptor whose activation causes mobilization of intracellular Ca(2+).

Animals↗

Influence of interleukin-1beta and hyaluronan on proteoglycan release from equine navicular hyaline cartilage and fibrocartilage.

Proteoglycan (PG) release, in response to recombinant human interleukin-1beta (rh-IL-1beta), was measured in cartilage explants obtained from the equine distal sesamoid bone (navicular bone). Fibrocartilage from the surface of the navicular bone apposing the deep digital flexor tendon and hyaline cartilage from the surface of the navicular bone articulating with the middle phalanx were labelled with 35SO4. Hyaline cartilage from the distal metacarpus was used as a control tissue. Following radiolabel incorporation, the three cartilage types were treated with rh-IL-1beta (100 U/mL) in the presence of hyaluronan (0.2, 2, 20, 200 and 2000 microgram/mL). rh-IL-1beta-Induced PG release was measured by scintillation assay of PG-bound radiolabel. Increases in PG release of 94% (P < 0.01), 101% (P < 0.05) and 122% (P < 0.05), in response to rh-IL-1beta, were noted in fibrocartilage, navicular hyaline cartilage and metacarpal hyaline cartilage, respectively. Hyaluronan (0.2 microgram/mL) significantly reduced rh-IL-1beta-induced PG release in metacarpal hyaline cartilage (P < 0.01). In fibrocartilage and navicular hyaline cartilage, hyaluronan did not reduce PG release and at some concentrations appeared to increase PG release, although this was not statistically significant. These experiments show that (i) fibrocartilage and hyaline cartilage of the navicular bone release PGs in response to rh-IL-1beta, and (ii) hyaluronan does not prevent rh-IL-1beta-induced breakdown of navicular bone cartilage.

Adjuvants, Immunologic↗

[Evaluation of the severity of glomerular damage in IgA nephropathy: significance of hyaline glomeruli in pattern classification].

Hyaline glomeruli are observed frequently in biopsied samples with mild to severe glomerular damage. We thus investigated whether or not all hyaline glomeruli have the same semiquantitative values in order to predict accurately the renal prognosis. We histopathologically studied 503 patients with IgA nephropathy (256 males and 247 females; mean age: 32.1 +/- 13.5 yrs), whose prognoses were followed for more than 3 yrs (mean follow-up period: 9.3 +/- 4.5 yrs). Cases with severely damaged prolifero-sclerotic glomeruli showed poor prognoses (severely damaged glomeruli: (-) vs ( renal death rate: 6% vs 52%, p < 0.0001; the 15 year-survival rate: 89% vs 52%, p < 0.0001) and hyaline glomeruli were seen in 68% of the cases. Hyaline glomeruli were observed in 29% of the cases with mild glomerular damage. However, the renal prognosis was not affected by the presence of hyaline glomeruli based on the analysis of the generalized Wilcoxon test. These results indicated that hyaline glomeruli express two different characteristics for renal prognosis. Therefore, the appearance of hyaline glomeruli alone is less important for the prediction of renal prognosis, but the appearance of both glomeruli with hyalinosis and those with severe damage was found useful in accurately predicting the renal prognosis.

Adolescent↗

Lectin histochemistry of the hyaline layer around the larvae of Patiriella species (Asteroidea) with different developmental modes.

Larvae of sea stars are surrounded by an extracellular matrix called the hyaline layer. The lectin-binding properties of this matrix were investigated in an ultrastructural study of Patiriella species having different modes of development. The planktonic bipinnaria and brachiolaria of P. regularis and the planktonic brachiolaria of P. calcar demonstrated the same labeling of the hyaline layer for three lectins: Con A, SBA, and WGA. In both species the outer coarse meshwork stained for all three lectins, whereas the intervillous layer displayed patchy labeling. In the benthic brachiolaria of P. exigua, the outer coarse meshwork displayed heavy labeling for all three lectins. The heavy labeling of the outer coarse meshwork of P. exigua compared with that of the other species suggests an increased number of lectin binding sites in the hyaline layer of this species. The similar ultrastructure and histochemistry of the hyaline layer of P. regularis and P. calcar may reflect similar requirements of their extracellular cover in their planktonic environment. Lectin labeling shows that hypertrophy of the hyaline layer of P. exigua, in particular the outer coarse meshwork, involves elaboration of the carbohydrate composition of the matrix. Modifications seen in the ultrastructure and histochemistry of the hyaline layer of P. exigua appear to be associated with the evolution of benthic development.

Animals↗

Immunolocalization of hyalin in sea urchin eggs and embryos using an antihyalin-specific monoclonal antibody.

Monoclonal antibodies were raised against purified cortical secretory vesicles (CVs) from the eggs of Strongylocentrotus purpuratus. One of the monoclonal antibodies (MAb 69-10, an IgA) was shown by immunofluorescence labeling of intact and detergent-lysed CVs to be directed against a CV content antigen. Immunoblot analysis of CVs revealed that MAb 69-10 bound to a major CV polypeptide with an Mr similar to that of hyalin (i.e., 300,000). MAb 69-10 was subsequently shown to bind to purified hyalin prepared from S. purpuratus and to cross react with hyalin prepared from Lytechinus pictus. Immunogold labeling on thin sections of unfertilized S. purpuratus eggs showed that hyalin was localized to the electron-lucent portion of CVs. This result is in agreement with the labeling pattern obtained by Hylander and Summers (Dev Biol 93:368-380, 1982) using polyclonal antihyalin antibodies. In fertilized eggs and later-stage embryos, hyalin was observed to be located on the external surface of the embryo. MAb 69-10 should be useful in studies of the structure of hyalin and its function in morphogenesis.

Animals↗