Synthetic bile acid derivatives induce nonapoptotic death of human retinal pigment epithelial cells.

PURPOSE: To study whether the synthetic ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) derivatives, which we have synthesized and have reported their apoptosis-inducing effect, have the effect on the proliferation of retinal pigment epithelial cells. METHODS: UDCA, CDCA, and their synthetic derivatives were administered in culture to the human retinal pigment cell line, ARPE-19. The effect on cell viability and growth was assessed by trypan blue dye exclusion. In order to evaluate the type of cell death, mitochondrial membrane potential assay, DNA electrophoresis, TUNEL assay, nuclear staining and Western blotting for caspase-3 and poly(ADP-ribose) polymerase (PARP) activities were conducted. RESULTS: Unlike UDCA and CDCA, which did not exhibit a significant effect on viability, their synthetic derivatives decreased the viability of ARPE-19 cells in a concentration-dependent manner. The cells treated with the synthetic derivatives did not demonstrate the characteristic findings of apoptosis, such as DNA ladder, DNA fragmentation, nuclear condensation or fragmentation, and caspase-3 and PARP activation. The reduction of mitochondrial membrane potential was shown. In electron microscopical study nuclear condensation was not shown. CONCLUSIONS: The synthetic UDCA and CDCA derivatives induced nonapoptotic death of ARPE-19 cells.

Analysis of upstream elements in the HuC promoter leads to the establishment of transgenic zebrafish with fluorescent neurons.

HuC encodes an RNA binding protein homologous to Drosophila elav that serves as an excellent early marker for differentiating neurons. We have characterized the promoter of the zebrafish HuC gene by examining the ability of 5'-upstream fragments to drive expression of green fluorescent protein (GFP) in live embryos. We determined that 2.8 kb of the 5'-flanking sequence is sufficient to restrict GFP gene expression to neurons. The core promoter spans 251 base pairs and contains a CCAAT box and one SP1 sequence but no TATA box is present near the transcription start site. A putative MyT1 binding site and at least 17 E-box sequences are necessary to maintain the neuronal specificity of HuC expression. Interestingly, sequential removal of the putative MyT1 binding site and 14 distal E boxes does not appear to abolish neuronal expression; rather, it leads to a progressive expansion of GFP expression into muscle cells. Further removal of the three proximal E boxes eliminates neuronal and muscle specificity of GFP expression and leads to ubiquitous expression of GFP in the whole body. Identification of key components of the HuC promoter has led to the establishment of a stable zebrafish transgenic line (HuC-GFP) in which GFP is expressed specifically in neurons. We crossed mind bomb (mib) fish with this line to visualize their neurogenic phenotype in live mib(-/-) mutant embryos. This cross illustrates how HuC-GFP fish could be used in the future to identify and analyze zebrafish mutants with an aberrant pattern of early neurons.

Elevated levels of hepatocyte nuclear factor 3beta in mouse hepatocytes influence expression of genes involved in bile acid and glucose homeostasis.

The winged helix transcription factor, hepatocyte nuclear factor-3beta (HNF-3beta), mediates the hepatocyte-specific transcription of numerous genes important for liver function. However, the in vivo role of HNF-3beta in regulating these genes remains unknown because homozygous null HNF3beta mouse embryos die in utero prior to liver formation. In order to examine the regulatory function of HNF-3beta, we created transgenic mice in which the -3-kb transthyretin promoter functions to increase hepatocyte expression of the rat HNF-3beta protein. Postnatal transgenic mice exhibit growth retardation, depletion of hepatocyte glycogen storage, and elevated levels of bile acids in serum. The retarded growth phenotype is likely due to a 20-fold increase in hepatic expression of insulin-like growth factor binding protein 1 (IGFBP-1), which results in elevated levels in serum of IGFBP-1 and limits the biological availability of IGFs required for postnatal growth. The defects in glycogen storage and serum bile acids coincide with diminished postnatal expression of hepatocyte genes involved in gluconeogenesis (phosphoenolpyruvate carboxykinase and glycogen synthase) and sinusoidal bile acid uptake (Ntcp), respectively. These changes in gene transcription may result from the disruptive effect of HNF-3beta on the hepatic expression of the endogenous mouse HNF-3alpha,-3beta, -3gamma, and -6 transcription factors. Furthermore, adult transgenic livers lack expression of the canalicular phospholipid transporter, mdr2, which is consistent with ultrastructure evidence of damage to transgenic hepatocytes and bile canaliculi. These transgenic studies represent the first in vivo demonstration that the HNF-3beta transcriptional network regulates expression of hepatocyte-specific genes required for bile acid and glucose homeostasis, as well as postnatal growth.

Congenital nasolacrimal duct obstruction: irrigation or probing?

The authors investigated the efficacy of antibiotic irrigation as the therapeutic option in congenital nasolacrimal duct obstruction. We retrospectively reviewed the medical record of 76 patients' eyes in whom congenital nasolacrimal duct obstruction had been diagnosed. In 50 of these patients, the colonizing microorganism was identified and, irrigation through canaliculi was performed using antibiotics of suitable sensitivity. Nasolacrimal system probing was performed on 26 patients as the control group. Treatment was regarded successful when over a 4 week period epiphora or mucous discharge disappeared and when saline passed without resistance on irrigation. 96.0% of patients in the irrigation group and 84.6% of patients in probing group were treated successfully. There was no statistical difference in the success rate between the two groups (P = 0.173). The recovery period based on culture results was 3.22 +/- 0.37 months in the group in which microorganisms were isolated and 2.39 +/- 0.35 months in the group in which no organisms were isolated. There were no statistically significant differences in the success rates between the group in which there was growth and the group in which there was no growth (P = 0.1308). Thus a similar result was obtained using nasolacrimal probing and canaliculus antibiotic irrigation in congenital nasolacrimal duct obstruction. Antibiotic irrigation is a safe and simple therapeutic option in congenital nasolacrimal duct obstruction.

Premature expression of the winged helix transcription factor HFH-11B in regenerating mouse liver accelerates hepatocyte entry into S phase.

Two-thirds partial hepatectomy (PH) induces differentiated cells in the liver remnant to proliferate and regenerate to its original size. The proliferation-specific HNF-3/fork head homolog-11B protein (HFH-11B; also known as Trident and Win) is a family member of the winged helix/fork head transcription factors and in regenerating liver its expression is reactivated prior to hepatocyte entry into DNA replication (S phase). To examine whether HFH-11B regulates hepatocyte proliferation during liver regeneration, we used the -3-kb transthyretin (TTR) promoter to create transgenic mice that displayed ectopic hepatocyte expression of HFH-11B. Liver regeneration studies with the TTR-HFH-11B mice demonstrate that its premature expression resulted in an 8-h acceleration in the onset of hepatocyte DNA replication and mitosis. This liver regeneration phenotype is associated with protracted expression of cyclin D1 and C/EBPbeta, which are involved in stimulating DNA replication and premature expression of M phase promoting cyclin B1 and cdc2. Consistent with the early hepatocyte entry into S phase, regenerating transgenic livers exhibited earlier expression of DNA repair genes (XRCC1, mHR21spA, and mHR23B). Furthermore, in nonregenerating transgenic livers, ectopic HFH-11B expression did not elicit abnormal hepatocyte proliferation, a finding consistent with the retention of the HFH-11B transgene protein in the cytoplasm. We found that nuclear translocation of the HFH-11B transgene protein requires mitogenic signalling induced by PH and that its premature availability in regenerating transgenic liver allowed nuclear translocation to occur 8 h earlier than in wild type.

Third cranial nerve palsy in children.

PURPOSE: To report the causes and the sensory, motor, and cosmetic results after treatment for oculomotor (third cranial nerve) palsy in children. METHODS: Review of the clinical records of children with a diagnosis of third cranial nerve palsy followed up in a university-based pediatric ophthalmology practice between 1981 and 1996. RESULTS: Forty-nine children with 53 affected eyes were followed up for a mean of 5.5 years. Third cranial nerve palsy was partial in 31 children (32 eyes) and complete in 18 children (21 eyes). The palsy was congenital in 20 eyes and caused by postnatal trauma in 17 eyes. Seventeen eyes had aberrant regeneration and four eyes with partial third cranial nerve palsy had spontaneous resolution. Thirty-six children (38 eyes) were affected before visual maturation (age 8 years), and 25 (27 eyes) had amblyopia. Of the five amblyopic eyes with quantifiable visual acuity, none had measurable improvement of Snellen visual acuity during the follow-up period. Overall, visual acuity was between 6/5 and 6/12 at the last follow-up visit in 31 eyes (58%). Ocular alignment was greatly improved after strabismus procedures, with a mean of 1.5 procedures for patients with partial third cranial nerve palsy and 2.3 procedures for those with complete palsy. Binocular function was difficult to preserve or restore but was achieved for some patients with partial third cranial nerve palsy. CONCLUSIONS: Surgical treatment of third cranial nerve palsy is frequently necessary, especially in cases of complete palsy. Multiple strabismus procedures are often needed to maintain good ocular alignment. Surgery can result in cosmetically acceptable alignment of the eyes, but it rarely results in restoration or achievement of measurable binocular function. Treatment of amblyopia is effective in maintaining the level of visual acuity present at the onset of the third cranial nerve palsy, but improvement in visual acuity is difficult to achieve.

Results following treatment of third cranial nerve palsy in children.

PURPOSE: To investigate the etiology, sensory, motor, and cosmetic results of treatment for oculomotor (CNIII) palsy in children. METHODS: We conducted a retrospective review of the clinical records of children with a diagnosis of CNIII palsy who were followed up in our practice between 1981 and 1996. RESULTS: During the 15-year period, 49 children with 53 affected eyes were followed for a mean of 5.5 years. CNIII palsy was congenital in one third of cases and secondary to postnatal trauma in another third. Thirty-three of the eyes were affected before visual maturation (age 8 years) and 27 eyes developed amblyopia. None of the 6 eyes with amblyopia in which visual acuity could be quantitated had measurable improvement of Snellen acuity after treatment. Overall, visual acuity was between 6/5 and 6/12 at the last follow-up visit in 56% of affected eyes. Ocular alignment was greatly improved after recess-resect procedures on the horizontal rectus muscles, but binocular function was difficult to preserve or restore. Blepharoptosis improved after levator palpebrae muscle resection or eyelid suspension procedures. CONCLUSIONS: CNIII palsy may undergo partial resolution in children, but surgical treatment is frequently necessary. Although surgery can result in cosmetically acceptable alignment of the eyes, it rarely results in restoration or achievement of binocular function. Multiple procedures are often necessary to maintain good ocular alignment. Several surgical procedures may be needed to correct related blepharoptosis and maintain an acceptable eyelid position. Treatment of amblyopia is only effective in maintaining the level of visual acuity present at the onset of the CNIII palsy, and improvement in acuity is difficult to achieve.