A newly established culture method highlights regulatory roles of retinoic acid on morphogenesis and calcification of mammalian limb cartilage

During mammalian embryogenesis, sclerotome-derived chondrocytes in the limb bud are arranged into a complicated bone shape with specific areas undergoing hypertrophy and calcification, creating a region-specific mineralized pattern in the cartilage. To follow chondrogenesis progression in vitro, we isolated limb cartilage from mice on embryonic day 13 (E13) and cultured it at the air-liquid interface after microsurgical removal of the ectoderm/epidermis. Explants underwent proper morphogenesis, giving rise to complete templates for limb bones in vitro. We found that region-specific calcification patterns resembling limbs of prepartum mature embryos could be induced in explants using culture medium containing high concentrations of CaCl2 (Ca), ascorbic acid (AA), and β-glycerophosphoric acid (BGP). In this culture system, excess amounts of all-trans retinoic acid (RA) severely disrupted morphogenesis and calcification patterns in limb cartilage. These effects were more pronounced in forearms than in phalanges. Although dissociated, the nascent chondrocytes in culture did not give rise to cartilage units even though augmented calcification was induced in these cell aggregates in the presence of RA. Taken together, our newly established culture system revealed that RA independently regulates three-dimensional morphogenesis and calcification.

Extracellularly Extruded Syntaxin-4 Is a Potent Cornification Regulator of Epidermal Keratinocytes

In the skin epidermis, keratinocytes undergo anchorage-dependent cornification, which gives rise to stratified multilayers, each with a distinct differentiation feature. The active formation of the cornified cell envelope (CCE), an important element in the skin barrier, occurs in keratinocytes of the upper epidermal layers and impacts their terminal differentiation. In the present study, we identified the extracellularly extruded syntaxin-4 as a potent differentiation regulator of epidermal keratinocytes. We found that differentiation stimuli led to the acceleration of syntaxin-4 exposure at the keratinocyte cell surface and that the artificial control of extracellular syntaxin-4, either by the forced expression of several syntaxin-4 mutants with structural alterations at the putative functional core site (AIEPQK), or by using antagonistic circular peptides containing this core sequence, dramatically influenced the CCE formation, with spatial misexpression of TGase1 and involucrin. We also found that the topical application of a peptide that exerted the most prominent antagonistic activity for syntaxin-4, named ST4n1, evidently prevented the formation of the hyperplastic and hyperkeratotic epidermis generated by physical irritation in HR-1 mice skin. Collectively, these results demonstrate that extracellularly extruded syntaxin-4 is a potent regulator of CCE differentiation, and that ST4n1 has potential as a clinically applicable reagent for keratotic skin lesions.

Krtap11-1, a hair keratin-associated protein, as a possible crucial element for the physical properties of hair shafts

BACKGROUND

The physical properties of the hair are predominantly determined by the assembly of keratin bundles. The keratin-associated proteins (Krtaps) are thought to be involved in keratin bundle assembly, however, the functional role of the individual member still remains largely unknown.

OBJECTIVE

The aim of this study is to clarify the role of a unique class of Krtaps, Krtap11-1, in the development and physical properties of the hair.

METHODS

The expression regulation of Krtap11-1 was analyzed and its binding partners in the hair cortex were determined. Also, the effects of the forcible expression of this protein on the hair follicle development were analyzed in culture.

RESULTS

The expression pattern of Krtap11-1 was concentrically asymmetric in the faulty hair that develops in Foxn1nu mice. In cultured keratinocytes, the expression of Krtap11-1 transgene product was strictly regulated by the keratinization process and proteasome-dependent protein elimination. While the association with keratin as well as the cohesive self-assembly of Krtap11-1 appeared to be stabilized by disulfide cross-links, the biotinylated Krtap11-1 probe enabled the adherence to certain type I keratins in the hair cortex, including K31, 33 and 34, in the absence of disulfide formation. When embryonic upper lip rudiments were forcibly introduced with Krtap11-1, the hair follicles formed irregularly arranged globular hair keratin-clumps surrounded by multilayered epithelial cells in culture.

CONCLUSION

Krtap11-1 may play an important role on keratin-bundle assembly in the hair cortex and this study provides insight into the physical properties of the hair shaft.

Enhanced disruption of the blood-aqueous barrier and the incidence of angiographic cystoid macular edema by topical timolol and its preservative in early postoperative pseudophakia

OBJECTIVE

To investigate the effects of timolol maleate with preservative and its preserved (PV) and nonpreserved vehicles (NPV) (benzalkonium chloride) on the blood-aqueous barrier and angiographic cystoid macular edema (CME) in early postoperative pseudophakia.

PATIENTS AND METHODS

Patients with ocular hypertension, normal tension glaucoma, and primary open-angle glaucoma who underwent surgery for cataracts. The study included a double-masked trial for timolol, PV, and NPV and a single-masked trial on the effect of diclofenac sodium and fluorometholone acetate on all three. The patients were divided into 6 groups, each of which were simultaneously administered the following different combinations of compounds: timolol and diclofenac (group A), timolol and fluorometholone (group B), PV and diclofenac (group C), PV and fluorometholone (group D), NPV and diclofenac (group E), and NPV and fluorometholone (group F). The 6 groups were then compared using a laser flare cell meter to determine the degree of disruption of the blood-aqueous barrier and fluorescein angiography to investigate angiographic CME. The differences in mean daily fluctuations in intraocular pressure were compared on the preoperative baseline day and for 5 weeks postoperatively. Twice daily administration of 0.5% timolol maleate or the vehicles was started 2 days before surgery, and continued until 5 weeks after surgery. Diclofenac or fluorometholone drops were instilled in the eyes 4 times preoperatively, on the day of surgery, and 3 times daily for 5 weeks postoperatively.

RESULTS

The flare amount was higher on the third and seventh days in group B than in group D, but was the same after the seventh day. The incidence of angiographic CME was the same between both groups. These 2 factors were significantly lower in group F. These 2 factors were also significantly lower in the 3 groups that received diclofenac instead of fluorometholone, with no difference among these groups. The intraocular pressure decline was significant in groups that received timolol compared with groups that received PV or NPV.

CONCLUSIONS

Timolol and its preservative, benzalkonium chloride, cause disruption of the blood-aqueous barrier in early postoperative pseudophakia and increased incidence of angiographic CME. The concurrent administration of nonsteroidal anti-inflammatory drug such as diclofenac prevents these adverse effects without interfering with the drop in intraocular pressure caused by timolol. The addition of benzalkonium chloride to timolol contributes considerably to these adverse effects.

CLINICAL RELEVANCE

The present results suggest the cause of similar complications produced by other antiglaucoma eyedrops containing similar preservatives.

Latanoprost accelerates disruption of the blood-aqueous barrier and the incidence of angiographic cystoid macular edema in early postoperative pseudophakias

OBJECTIVE

To study the effect of latanoprost, a prostaglandin analog, on the blood-aqueous barrier and angiographic cystoid macular edema (CME) formation in early postoperative pseudophakias.

PATIENTS AND METHODS

Included in the study were eyes with ocular hypertension, normal-tension glaucoma, or primary open-angle glaucoma undergoing surgery for cataract. The study consisted of a randomized double-masked trial for latanoprost and an open-label controlled trial for determining the effects of diclofenac sodium or fluorometholone eyedrop use on latanoprost or its placebo. We compared 4 groups of eyes with concurrent application of latanoprost and diclofenac (group A), latanoprost and fluorometholone (group B), latanoprost placebo and diclofenac (group C), and latanoprost placebo and fluorometholone (group D). A laser flare cell meter was used to determine the severity of blood-aqueous barrier disruption, and fluorescein angiography was performed to determine angiographic CME formation. Mean diurnal intraocular pressure differences were compared on the preoperative baseline day and in the fifth postoperative week. Latanoprost (0.005%) or its placebo was given once a day starting 2 days before surgery until the fifth postoperative week. Diclofenac or fluorometholone eyedrops were given 4 times a day before surgery on the day of surgery and 3 times a day until the fifth postoperative week.

RESULTS

In group B compared with group D, the amount of flare 3 days and 1 and 2 weeks after surgery and the incidence of angiographic CME in the fifth postoperative week were significantly higher. These 2 factors were significantly higher in group B than in group A (P < .05) and in group D than in group C (P < .01). There was no significant difference in these factors between groups A and C. The intraocular pressure decline was significant in groups A and B compared with groups C and D (P < .05), but there was no significant difference between groups A and B and between groups C and D.

CONCLUSIONS

Latanoprost therapy enhances disruption of the blood-aqueous barrier and increases the incidence of angiographic CME formation in early postoperative pseudophakias. Because administration of nonsteroidal eyedrops such as diclofenac seems to prevent the adverse effects of latanoprost therapy while maintaining its effect to lower intraocular pressure, we suggest their concurrent application.

Correlation between intraocular lens hydrophilicity and anterior capsule opacification and aqueous flare

PURPOSE

To study the correlation between a basic parameter of intraocular lens biocompatibility, hydrophilicity, and two clinical parameters, postoperative inflammation and anterior capsule opacification.

SETTING

Miyake Eye Hospital, Nagoya, Japan.

METHODS

Three combinations of IOLs that were identical in shape but had distinct contact angles of water were used in this prospective double-masked study: (1) experimental comparison of collagen type IV and poly(methyl methacrylate) (PMMA) IOLs in rabbit eyes; (2) clinical comparison of heparin-surface-modified and PMMA IOLs; (3) clinical comparison of three foldable IOLs, silicone, acrylic, and memory. One of the two IOLs being compared in each situation was randomly assigned to both eyes of each animal or patient. At 1 and 3 months postoperatively, the degree of anterior capsule opacification and the amount of flare in the anterior chamber were determined.

RESULTS

In all three comparative situations, greater postoperative inflammation and more rapid anterior capsule opacification was seen in the eyes with hydrophobic IOLs.

CONCLUSION

There was a correlation between the hydrophilicity of an IOL and the severity of postoperative inflammation and the speed of anterior capsule opacification.

[Corneal autofluorescence in eyes with branch retinal vein occlusion]

Basic studies have suggested that corneal autofluorescence, originating from flavoprotein and pyridine nucleotides, is caused by metabolically impaired corneal mitochondrial respiration. In this study, we used corneal autofluorescence as a parameter for evaluating the pathology at the corneal cell level in eyes with branch retinal vein occlusion. Unilateral branch retinal vein occlusion cases with durations of 2 months to 7 years since the onset and age-matched normal eyes were used for the study. The corneal autofluorescence was measured with a Fluorotron Master, with a special device attached to measure the anterior segment at the corneal peak. The autofluorescence was 15.6 +/- 5.8 (n = 68), 13.8 +/- 4.0 (n = 68), 14.2 +/- 3.7 (n = 14), and 14.0 +/- 3.6 (n = 14) (ng Eq/ml, mean +/- SD), respectively, in eyes with branch retinal vein occlusion, their fellow eyes, normal controls, and their fellow eyes. The affected eyes showed statistically significantly higher autofluorescence than the fellow eyes; there was no essential difference among the fellow eyes of those with branch retinal occlusion, normal controls, and their fellow eyes. The eyes with branch retinal vein occlusion, which is a focal retinal lesion, commonly exhibit corneal cellular pathologies.

Increased aqueous flare as a result of a therapeutic dose of mannitol in humans

To evaluate the effects of mannitol on aqueous flare (aqueous protein concentration), we administered an intravenous clinical therapeutic dose to normal young adults (average age 20.1 years), to normal older adults (average age 61.5 years), and also to patients with diabetes mellitus, systemic hypertension, or pseudoexfoliation syndrome who were about to undergo intraocular surgery (average age 66.4 years). Protein and cell levels in the aqueous were determined with a device that measures laser light scatter in the aqueous. Mannitol increased the intensity of aqueous flare. In all subjects, the intensity of aqueous flare was greatest around 1 h following drug administration; the magnitude and duration of the aqueous flare increase were significantly greater in normal older adults than in normal young adults; the magnitude was essentially the same in older adults with and without disease. The effect reversed within 6 h of drug administration in normal subjects. We consider the findings to represent changes in actual aqueous protein concentration and discuss the possible causes of this phenomenon.

[Increase in aqueous flare by a therapeutic dose of mannitol in humans]

To evaluate the effects of mannitol on aqueous flare (aqueous protein concentration), we administered an intravenous clinical therapeutic dose to normal young adults (average age, 20.1 years), to normal older adults (average age, 61.3 years), and also to patients with diabetes mellitus, systemic hypertension, or pseudoexfoliation syndrome who were about to undergo intraocular surgery (average age, 66.4 years). Protein and cell levels in the aqueous fluid were determined with a device that measures laser light scattering in the aqueous fluid. Mannitol increased aqueous flare intensity. In all subjects, aqueous flare intensity was greatest around one hour following drug administration; the magnitude and the duration of the aqueous flare increase were significantly greater in normal older subject than in normal young adults; the magnitude was essentially the same in older adults with and without diseased barrier. The effect was reversed within 6 hours of drug administration in normal subjects. We considered the findings to represent changes in actual aqueous protein concentration and discussed the possible causes of this phenomenon.

Pupillary fibrin membrane. A frequent early complication after posterior chamber lens implantation in Japan

The incidence of pupillary fibrin membrane formation, a relatively frequent complication of cataract surgery in Japan even for experienced surgeons, was noted in 2038 consecutive cases of senile cataract removal and primary posterior chamber intraocular lens (PC IOL) implantation. The overall incidence was 4.4%. Comparisons among cases showed the incidence to be significantly higher among: (1) patients who received dry- versus wet-sterilized lenses (P less than 0.001), (2) eyes with premature, subcapsular, or nuclear cataracts than among those with mature cataracts (P less than 0.05), (3) patients with systemic hypertension (P less than 0.01), (4) eyes not treated postsurgically with topical antiprostaglandins (P less than 0.001), and (5) patients who had undergone previous PC IOL implantation in the fellow eye (P less than 0.001). These findings suggest that the formation of the fibrin membrane is a kind of immunologic reaction. Accordingly, use of antiprostaglandin agents and complete removal of lens material and epithelial cells are recommended, especially for patients undergoing second-eye operations or those with a predisposition to breakdown of the blood-aqueous barrier.

Serial magnetic resonance imaging in subacute sclerosing panencephalitis

Magnetic resonance (MR) imaging of a 17-year-old girl with subacute sclerosing panencephalitis (SSPE) was done several times to monitor the morphological changes and clinical course of the disease by comparison with computed tomographic (CT) scans. The MR image showed lesions that corresponded to the clinical symptoms in the early stages where no abnormalities appeared on the CT scans. The MR images delineated the extent of abnormal areas more clearly than the CT scans. However, the course of neurological manifestations did not always correspond to the MR findings. Serial MR imaging was useful in the detection and observation of the stages and clinical progress of SSPE.

Outward transport of fluorescein from the vitreous in aphakic eyes

By administering fluorescein intravenously to 95 patients we calculated the ratio of fluorescein concentration in the vitreous at the time of its peak level compared with the estimated unbound concentration of fluorescein in the plasma at the same time. We studied 12 normal phakic and 83 aphakic eye approximately two months, one year, and more than two years after cataract extraction. All the eyes had undergone intracapsular cataract extraction or extracapsular cataract extraction, with or without posterior capsulotomy, because of senile cataract. The calculated ratio in patients with intracapsular and extracapsular lens extraction was statistically significantly reduced at two months and one year after cataract extraction and was normalised at more than two years after the operation in comparison with normal subjects. The ratio was statistically extracapsular extraction at two months and one year after surgery. Posterior capsulotomy had no effect on the ratio. The ratio, we considered, at least partially reflects the outward transport of fluorescein from the vitreous cavity. Although the findings reflect subclinical phenomena, they are of importance when considering postoperative sequelae. The posterior lens capsule, zonule, and intact anterior vitreous face may be essential for the anterior uvea to function in the outward transport of fluorescein from the vitreous cavity.

Consensual reactions of human blood-aqueous barrier to implant operations

Slit-lamp fluorophotometry was used to evaluate the disruption of the blood-aqueous barrier in eyes that underwent posterior chamber lens implantation following phacoemulsification and the consensual reaction of the barrier disruption in the contralateral eyes. Topical indomethacin or placebo was applied to surgically treated eyes to test the effect on the barrier disruption. Fluorophotometry was carried out before operation and 24 hours, one week, and four weeks after operation. In the surgically treated eyes, topical indomethacin effectively inhibited the disruption of the barrier during the first and fourth postoperative weeks; in the contralateral eyes it did not inhibit the reaction. The consensual reaction was observed in higher magnitude and frequency than expected. Its magnitude and frequency were higher during the first postoperative day than during the first or fourth postoperative weeks, but were proportional to the barrier disruption of the surgically treated eyes during the first postoperative day only.

Incidence of cystoid macular edema after retinal detachment surgery and the use of topical indomethacin

We conducted a prospective, double-masked, controlled study to determine the effects of indomethacin in preventing the development of cystoid macular edema after retinal detachment surgery. In addition to routine medication, topical indomethacin was applied to 63 eyes (52 with intact lenses and 11 aphakic) and a placebo was applied to 61 eyes (51 with intact lenses and ten aphakic) that underwent retinal detachment surgery. Indomethacin drops or placebo were instilled once an hour for five hours preoperatively and three times daily for four weeks postoperatively. Fluorescein angiography, done before surgery and four to six weeks after surgery to detect cystoid macular edema, showed that cystoid macular edema developed in 11 of 63 eyes (13%) in the indomethacin-treated group and in 20 of 61 eyes (33%) in the placebo group (P less than .01). Five of 28 eyes (18%) with cystoid macular edema in both groups and 38 of 96 eyes (40%) without cystoid macular edema in both groups had visual acuities of 20/40 or better (P less than .05).