Identification of the gene responsible for gelatinous drop-like corneal dystrophy

Gelatinous drop-like corneal dystrophy (GDLD; OMIM 204870) is an autosomal recessive disorder characterized by severe corneal amyloidosis leading to blindness, with an incidence of 1 in 300,000 in Japan. Our previous genetic linkage study localized the gene responsible to a 2.6-cM interval on chromosome 1p. Clinical manifestations, which appear in the first decade of life, include blurred vision, photophobia and foreign-body sensation. By the third decade, raised, yellowish-grey, gelatinous masses severely impair visual acuity, and lamellar keratoplasty is required for most patients. Here we report DNA sequencing, cDNA cloning and mutational analyses of four deleterious mutations (Q118X, 632delA, Q207X and S170X) in M1S1 (formerly TROP2 and GA733-1), encoding a gastrointestinal tumour-associated antigen. The Q118X mutation was the most common alteration in the GDLD patients examined, accounting for 33 of 40 (82.5%) disease alleles in our panel of families. Protein expression analysis revealed aggregation of the mutated, truncated protein in the perinuclear region, whereas the normal protein was distributed diffusely in the cytoplasm with a homogenous or fine granular pattern. Our successful identification of the gene that is defective in GDLD should facilitate genetic diagnosis and potentially treatment of the disease, and enhance general understanding of the mechanisms of amyloidosis.

Species difference in radioactivity elimination from liver parenchymal cells after injection of radiolabeled proteins

To elucidate the cause for the different levels of hepatic radioactivity among mammals after injection of protein radiopharmaceuticals, the metabolism of radiolabeled proteins and the fate of their radiometabolites in the parenchymal cells of rat liver were investigated and compared with those of mice. We used galactosyl-neoglycoalbumin (NGA) as a carrier protein, and NGA was labeled with 111In via 1-(4-isothiocyanatobenzyl)ethylenediaminetetraacetic acid (SCN-Bz-EDTA) or 1-[p-(5-maleimidopentyl)aminobenzyl]ethylenediaminetetraacetic acid (EMCS-Bz-EDTA) and with 125I via direct iodination. All radiolabeled NGAs exhibited rapid accumulation in liver parenchymal cells after intravenous injection into rats. Radioactivity was eliminated following NGA-125I injection at similar rates from rat and mouse liver. In contrast, both 111In-labeled NGAs demonstrated much slower elimination of radioactivity in rat when compared with mouse liver. Analyses of radioactivity in bile and liver indicated that both SCN-Bz-EDTA and EMCS-Bz-EDTA rendered mono-amino acid adducts as the final radiometabolites, which were generated in rat liver within 1 h postinjection. Subcellular distribution studies suggested that these radiometabolites were copurified with lysosome in rat liver. Because similar results were observed in mice previously, the difference between rats and mice in radioactivity elimination from liver parenchymal cells would be predominantly attributable to the different efflux rate of the 111In-labeled metabolites from the lysosome between these species. Such differences in the efflux rates of radiometabolites from the lysosome among mammals may also account for the different hepatic radioactivity levels of radiolabeled proteins between animal and clinical studies.

Ultrasonographic analysis of shoulder rotator cuff tears

Seventy-nine shoulders suspected of rotator cuff tears were examined by ultrasonography (US) and forty-three received surgery. Long and short axis scans were performed and findings of each were separately classified according to a five-grade system, and the results were correlated with the actual extent of tear observed during surgery. Internal echogenicity and subacromial impingement were analyzed before and after surgery. A accuracy of US in detecting rotator cuff tears was analyzed. In addition, the correlation between cuff shape observed by US before surgery and actual shape observed during surgery was assessed. It was noted that cuff thinning and abnormalities in shape did not recover to normal after surgery. However, in the cases of discontinuities observed by US before surgery, US findings indicated that the torn cuff was anchored to the greater tuberosity and functional during active motion. Although post-operative US findings were not normal, clinical results were good in most cases. Sensitivity of US for detecting rotator cuff tear was 100% and specificity 94%. US is non-invasive, cost effective and allows the physician to examine the joint while it is in motion. Therefore, at this time, we use US as a screening method for detecting rotator cuff tears. Furthermore, US allows us to check for re-tears while the joint is in motion, which is essential for accurate diagnosis.

An association between lipid peroxidation and alpha-naphthylisothiocyanate-induced liver injury in rats

An association between lipid peroxidation and alpha-naphthylisothiocyanate (ANIT)-induced liver injury was examined in rats injected once with the toxicant (75 mg/kg body weight). The severity of liver injury was estimated 12, 24, 48, and 72 h after ANIT injection. Liver injury appeared 24 h after ANIT injection, progressed at 48 h, and recovered at 72 h, judging from the serum levels of marker enzymes and components. Serum lipid peroxide (LPO) concentration increased 24 h after ANIT injection and further increased at 48 h, but this increase was attenuated at 72 h. In contrast, liver LPO content increased 12 h after ANIT injection and further increased 24 and 48 h, but this increase was attenuated at 72 h. Similarly, myeloperoxidase (MPO) activity, an index of neutrophil infiltration, in the liver tissue increased 12 h after ANIT injection and further increased at 24 and 48 h, but this increase was attenuated at 72 h. Either serum LPO concentration or liver LPO content was significantly correlated with liver MPO activity (r = 0.661 for serum LPO concentration; r = 0.585 for liver LPO content). These results suggest that lipid peroxidation might be associated with ANIT-induced liver injury in rats and that this lipid peroxidation might occur via oxygen radicals derived from neutrophils infiltrated into the liver tissue of ANIT-intoxicated rats.

Genetic variation of chlorella viruses: variable regions localized on the CVK2 genomic DNA

A physical map of the Chlorella virus CVK2 genomic DNA has been constructed based on a cosmid contig covering the entire genomic region. By using Southern blot analysis with 22 gene probes, the gene arrangement along the genome was compared between CVK2 and PBCV-1, the prototypic member of Phycodnaviridae, whose genomic sequence is now available. The major rearrangements were (1) an insertion of a 20-kbp region around the left end of CVK2 DNA, (2) a duplication of the gene for major capsid protein in CVK2 DNA, (3) deletions/insertions of some open reading frames, and (4) divergence in the terminal inverted repeat sequences. Despite these changes, extensive colinearity was revealed between most of the genes along the CVK2 and PBCV-1 genomes. These data imply that the Chlorella virus genome has an overall high degree of genomic stability, encompassing specific islands of rearrangements.

Gab-family adapter proteins act downstream of cytokine and growth factor receptors and T- and B-cell antigen receptors

We previously found that the adapter protein Gab1 (110 kD) is tyrosine-phosphorylated and forms a complex with SHP-2 and PI-3 kinase upon stimulation through either the interleukin-3 receptor (IL-3R) or gp130, the common receptor subunit of IL-6-family cytokines. In this report, we identified another adapter molecule (100 kD) interacting with SHP-2 and PI-3 kinase in response to various stimuli. The molecule displays striking homology to Gab1 at the amino acid level; thus, we named it Gab2. It contains a PH domain, proline-rich sequences, and tyrosine residues that bind to SH2 domains when they are phosphorylated. Gab1 is phosphorylated on tyrosine upon stimulation through the thrombopoietin receptor (TPOR), stem cell factor receptor (SCFR), and T-cell and B-cell antigen receptors (TCR and BCR, respectively), in addition to IL-3R and gp130. Tyrosine phosphorylation of Gab2 was induced by stimulation through gp130, IL-2R, IL-3R, TPOR, SCFR, and TCR. Gab1 and Gab2 were shown to be substrates for SHP-2 in vitro. Overexpression of Gab2 enhanced the gp130 or Src-related kinases-mediated ERK2 activation as that of Gab1 did. These data indicate that Gab-family molecules act as adapters for transmitting various signals.

Peripheral lamellar keratoplasty for corneoscleral cyst: three case reports

PURPOSE

To examine whether peripheral lamellar keratoplasty (LKP) using preserved cornea was effective for the treatment of corneoscleral cysts.

METHODS

Three patients with corneoscleral cysts underwent peripheral lamellar keratoplasty. Two patients had no history of trauma or ocular surgery and were considered to have congenital cysts. The other patient had a history of strabismus surgery that had been performed 7 years previously. The anterior wall of the cysts was removed by trephination, and the epithelial membrane lining the posterior wall was peeled off. Lamellar corneal buttons obtained from preserved corneas then were put in place and secured with 8-10 interrupted sutures. In one case, because the cyst was large and extended to the pupillary axis, peripheral LKP was performed for removal of the scleral and peripheral corneal cyst, and the inner wall of the central corneal cyst was removed with vigorous irrigation and a spatula.

RESULTS

Histologic examination showed that all of the cysts were lined with nonkeratinizing epithelial cells. In all three cases, cysts have not reformed after a 1-5-year follow-up.

CONCLUSIONS

The cysts were lined in epithelial cells, and removal of these epithelial cells was considered to be important for the prevention of recurrence. Peripheral LKP is effective for the treatment of corneoscleral cysts, since this procedure removes displaced epithelial cells and reconstructs the thin part of the cornea and sclera.

[Design and development strategy for wearable and implantable artificial endocrine pancreas]

The ultimate goal of development of an artificial endocrine pancreas is for long-term strict glycemic control, and therefore, the trend in development is now from bedside-type to wearable- or implantable-type. With either a miniaturized extracorporeal glucose monitoring system based on microdialysis sampling method or a ferrocene-mediated needle-type glucose sensor covered with highly biocompatible membrane, and with subcutaneous insulin infusion algorithm using short-acting insulin analogue, long-term physiological glycemic control could be obtained by wearable artificial endocrine pancreas. The next step will be directed to the implantable one. Non-invasive infrared absorbance spectroscopy to fit into an artificial tooth prosthesis, an implantable artificial endocrine pancreas, in which measured glucose concentrations are transmitted telemetrically to implanted computer and pump system, might be developed.

Abnormal FHIT transcripts found in both lung cancer and normal lung tissue

Occurrence of abnormal transcripts of the FHIT (fragile histidine triad) gene has been reported in various types of cancer. On the other hand, aberrant transcripts are sometimes found in non-neoplastic tissues, so the relationship between the presence of abnormal transcripts of the FHIT gene and cancer pathogenesis is controversial. We investigated alterations in the FHIT locus, detected by nested reverse transcription-polymerase chain reaction and/or allelic status, in 88 primary lung cancers and normal lung tissues, and 22 normal lung tissues with metastatic lung cancer as a control. The frequencies of abnormal transcripts were 59% in lung cancer, 35% in paired normal lung, and 64% in normal control lung; the difference in frequencies between lung cancer and paired normal lung was significant, while that between lung cancer and normal control lung was not. Sequence analysis revealed that there were no cancer-specific abnormal transcripts entirely missing two or more exons, nor were the abnormal transcripts of lung cancer identical with those of paired normal lung in the same individual. Furthermore, we found no correlation between loss of heterozygosity in the FHIT locus and occurrence of abnormal FHIT transcripts. These results suggest that the presence of abnormal FHIT transcripts, in terms of their frequency and variety, is not cancer-specific in lung carcinogenesis, and the abnormality may be mainly due to abnormal splicing and processing of the transcripts. To estimate the precise function of the FHIT gene, further study of the FHIT protein in lung carcinogenesis is needed.

Epithelial hyperproliferation and transglutaminase 1 gene expression in Stevens-Johnson syndrome conjunctiva

In Stevens-Johnson syndrome, pathological keratinization of the ordinarily nonkeratinized corneal and conjunctival mucosal epithelia results in severe visual loss. We examined conjunctiva covering cornea in five eyes in the chronic cicatricial phase of Stevens-Johnson syndrome. Normal conjunctiva from five age-matched individuals was studied also. The number of epithelial cells in Stevens-Johnson syndrome conjunctiva that were immunoreactive with a monoclonal antibody, Ki-67, to a nuclear antigen found only in proliferating cells was greater than normal (93.8+/-19.8 cells above 100 basal cells versus 12.8+/-0.5 cells above 100 basal cells; P = 0.009). In addition, although clinical inflammation was mild, massive lymphocytic infiltration was seen in the substantia propria of conjunctiva covering cornea. In situ hybridization documented transglutaminase 1 (keratinocyte transglutaminase) mRNA in suprabasal cells of the abnormally thickened conjunctival epithelium in all Stevens-Johnson syndrome patients. In contrast, no message was detected in normal conjunctival or corneal epithelia. Transglutaminase 1 is expressed during the terminal differentiation of keratinocytes where it helps synthesize cornified cell envelopes. We speculate that in Stevens-Johnson syndrome, epithelial hyperproliferation, and transglutaminase 1 gene expression lead to the pathological keratinization of ocular surface mucosal epithelia.

Anti-apoptotic function of Rac in hematopoietic cells

The small GTP-binding protein Rac plays a pivotal role in the regulation of diverse physiological events including reorganization of the actin cytoskeleton, cell cycle progression, and transformation. Here we show an anti-apoptotic effect of Rac in interleukin-3-dependent murine hematopoietic BaF3 cells. Activated Rac(G12V), when ectopically expressed in BaF3 cells, rendered the cells resistant to apoptosis upon interleukin-3 deprivation, while activated mutants of Rho and Cdc42 displayed no significant anti-apoptotic effect. In contrast to activated Ras, which also supports cell survival in the absence of interleukin-3, Rac required fetal bovine serum for the prevention of cell death. The involvement of phosphatidylinositol 3-kinase downstream of Rac was demonstrated by the inhibition of Rac-induced cell survival by wortmannin and LY294002 and the presence of phosphatidylinositol kinase activity in the Rac immunoprecipitate. Furthermore, the serine/threonine kinase Akt was stimulated by activated Rac and fetal bovine serum in a synergistic manner. Rac-induced Akt activation was mediated by phosphorylation of threonine-308 and serine-473. In addition to the phosphatidylinositol 3-kinase/Akt pathway, the p38 mitogen-activated protein kinase pathway was crucial for Rac-dependent survival, whereas p38 mitogen-activated protein kinase nas not implicated in Ras-induced anti-apoptotic signaling. These findings provide evidence for the involvement of Rac in survival signaling of hematopoietic cells.

In-vivo evaluation of indium-111-diethylenetriaminepentaacetic acid-labelling for determining the sites and rates of protein catabolism in mice

Pharmacokinetic analyses of protein pharmaceuticals are of prime importance for their clinical application. Because many proteins have pharmacological activity at low concentrations, radiolabelling of proteins is widely used to identify the sites and determine the rates of protein catabolism in-vivo due to the high sensitivity of detection of radioactivity. Recently, a metallic radionuclide, (111)In, has been used to trace the pharmacokinetics of proteins of interest after conjugation of the proteins with diethylenetriaminepentaacetic acid (DTPA). In this study, galactosyl-neoglycoalbumin (NGA) was reacted with the cyclic dianhydride of DTPA and labelled with (111)In to estimate the validity of this radiolabelling procedure for pharmacokinetic analyses. For comparison, we also evaluated direct radioiodination, because directly-radioiodinated proteins are widely used to assess the pharmacokinetics of proteins of interest. The hepatic radioactivity profile after intravenous injection of [131I]NGA or [(111)In]DTPA-NGA into mice was analysed pharmacokinetically, and the first-order rate constant representing the elimination of the respective radiometabolite from hepatic parenchymal cells was determined. The results indicated that direct radioiodination is inappropriate for pursuing the pharmacokinetics of the proteins, because of rapid elimination of the radioactivity from the sites of protein catabolism. These findings also implied that the [(111)In]DTPA label could be used to identify the catabolic sites and determine the rates of catabolism of proteins with relatively short biological half-lives, although characterization of radiolabelled species at the sites of accumulation would be required for accurate determination of the catabolic sites of proteins.

Signaling through Gp130: toward a general scenario of cytokine action

Cytokines play roles in a wide range of responses such as immune response, hematopoiesis and inflammation. A large volume of studies revealed that cytokines show functional pleiotropy and redundancy. Gp130 is a receptor subunit shared by the interleukin-6 family of cytokines. We describe and discuss signaling through gp130 in relation to a general scenario for cytokine signaling regulating cell growth, differentiation and survival.

Relation of inducible nitric oxide synthase activity to lipid peroxidation and nonprotein sulfhydryl oxidation in the development of stress-induced gastric mucosal lesions in rats

We have reported that increases in lipid peroxide (LPO) formation, nonprotein sulfhydryl (NP-SH) oxidation, and inducible NO synthase (iNOS) activity and a decrease in constitutive NO synthase (cNOS) activity in the gastric mucosa of rats with water immersion restraint (WIR) stress are closely related to gastric mucosal lesion development. Peroxynitrite, which is produced by the reaction of nitric oxide (NO) with superoxide anion, can initiate intracellular LPO formation and NP-SH oxidation, resulting in producing an extreme cellular membrane damage. In this study, the relation of changes in cNOS and iNOS activities to LPO formation and NP-SH oxidation was examined in the gastric mucosa of rats with WIR stress. An increase in iNOS activity, but not a decrease in cNOS activity, correlated well with an increase in LPO concentration (r = 0.750) and NP-SH concentration (r = -0.808) in the gastric mucosa of rats with WIR stress. In addition, the above-mentioned changes in iNOS activity and LPO and NP-SH concentrations with lesion development in the gastric mucosa of rats with WIR stress were attenuated with both prevention of the lesion development and an increase in the concentration of gastric mucosal nitrite/nitrate, the breakdown products of NO, by pretreatment with aminoguanidine, a selective iNOS inhibitor. These results suggest that in the gastric mucosa of WIR-stressed rats, NO produced by increased iNOS could contribute to enhanced LPO formation and NP-SH oxidation, resulting in lesion development.

[Augmented antitumor efficacy of combination chemotherapy of nedaplatin with 5-fluorouracil in in vivo murine and human tumor model]

Augmented antitumor activity was demonstrated in combination chemotherapy of Nedaplatin (NDP) or Cisplatin (CDDP) with 5-fluorouracil (5-FU) against murine lung carcinoma and human squamous carcinoma from head and neck. Either NDP or CDDP (1/4 to 1 maximum tolerated dose; MTD) was injected once and 5-FU (1/16 MTD) was injected daily for five days via tail vein to tumor-implanted mice. The sequential administration of either NDP or CDDP prior to 5-FU (NF or CF therapy) showed severe body weight loss followed by the toxic death of tumor-bearing mice at the MTD of NDP or CDDP. In contrast, the reverse sequence of the treatment, that is, 5-FU prior to NDP or CDDP (FN or FC therapy), resulted in the synergistically enhanced inhibition of tumor growth and the prolonged survival in comparison with NDP, CDDP or 5-FU monotherapy. The antitumor activities of the combinations of CDDP with 5-FU was less than those of the combination of NDP with 5-FU. Especially, at the MTD of NDP in FN therapy, long-term tumor-free survival was frequently observed. Thus, FN therapy was thought to be the most efficient regimen in combination of NDP with 5-FU as a clinical therapy.

Dissecting aortic aneurysm involving an anomalous right subclavian artery and isolated left vertebral artery: case report and review of the literature

A 54-year-old hypertensive woman was admitted with severe interscapular back pain. A chest radiograph showed marked widening of the mediastinum. Aortography demonstrated a DeBakey type III, a thoracic aortic dissection and an anomalous right subclavian artery which was associated with an isolated left vertebral artery. The patient underwent aortic arch replacement with 5 branches and made an uneventful recovery. As far as we can determine, this is the first reported occurrence of these anomalies together with acquired disease of the aorta.

Teprenone, an anti-ulcer agent, increases gastric mucosal mucus level via nitric oxide in rats

We examined whether the increasing action of teprenone (TP) on mucus synthesis and content in rat gastric mucosa is related to nitric oxide (NO) formation via NO synthase (NOS) in the tissue. TP (200 mg/kg)-induced increases in levels of gastric mucosal hexosamine and adherent mucus were inhibited with decreased gastric mucosal NOS activity and nitrite/nitrate concentration by co-administration of NG-monomethyl L-arginine (100 mg/kg), a NOS inhibitor, but not its D-isomer. These results suggest that TP exerts an increasing action on gastric mucus synthesis and content possibly under the condition of maintained NO production via NOS in gastric mucosal tissues, although the precise mechanisms for the action of TP is still unclear.

Gelatinous drop-like corneal dystrophy is not one of the beta ig-h3-mutated corneal amyloidoses

PURPOSE

To discover if beta ig-h3 is mutated in gelatinous drop-like corneal dystrophy, as has been suggested.

METHODS

Genomic DNA was isolated from unrelated individuals with lattice corneal dystrophy type I (n = 3), Avellino corneal dystrophy (n = 3), and gelatinous drop-like corneal dystrophy (n = 3) and used as a template for polymerase chain reaction to amplify all exons in beta ig-h3. The polymerase chain reaction product was then sequenced.

RESULTS

Beta ig-h3 is mutated in lattice corneal dystrophy type I (Arg124Cys) and Avellino corneal dystrophy (Arg124His). In gelatinous drop-like corneal dystrophy, on the other hand, no mutation was detected in the entire coding region of beta ig-h3 (all 17 exons).

CONCLUSION

Unlike the amyloidotic corneal dystrophies lattice type I and Avellino, gelatinous drop-like corneal dystrophy is not likely to be caused by a mutation in beta ig-h3.

STAT3 orchestrates contradictory signals in cytokine-induced G1 to S cell-cycle transition

The signal transducer and activator of transcription molecules (STATs) play key roles in cytokine-induced signal transduction. However, their role in cell growth has not been clear. In the present study, we show that STAT3 plays a key role in the G1 to S phase cell-cycle transition induced by the cytokine receptor subunit gp130, through the upregulation of cyclins D2, D3 and A, and cdc25A, and the concomitant downregulation of p21 and p27. Furthermore, unexpectedly, we found that gp130 could induce the expression of p21 when STAT3 activation was suppressed. Such contradictory signals regulating cell-cycle progression could be simultaneously delivered from distinct cytoplasmic regions of gp130. We propose an 'orchestrating model' for cytokine and growth factor action in which contradictory signals are orchestrated to produce a specific effect in a target cell.

Adenovirus-mediated gene transfer to nucleus pulposus cells. Implications for the treatment of intervertebral disc degeneration

STUDY DESIGN

In vitro and in vivo studies using a rabbit model were performed to determine the feasibility of adenovirus-mediated gene transfer to the intervertebral disc.

OBJECTIVES

This study was conducted to determine whether it is possible to transfer genes to cells within the intervertebral disc by direct injection of an adenovirus and to determine the duration of gene expression obtained by this method.

SUMMARY OF BACKGROUND DATA

Although growth factors have the potential to stimulate the regeneration of nucleus pulposus, sustained delivery of growth factors to a degenerated disc is clinically unfeasible with present technology. Novel approaches such as gene transfer should be investigated as possible solutions to this problem.

METHODS

The lacZ marker gene was used to evaluate gene delivery to cells within intervertebral discs. For the in vitro study, cell cultures were established from the nucleus pulposus tissue of New Zealand white rabbits and infected with an adenovirus encoding the lacZ gene (Ad-lacZ). For the in vivo study, the anterior aspects of lumbar intervertebral discs were surgically exposed, and Ad-lacZ in saline solution was directly injected into the nucleus pulposus. An equal volume of saline only was injected into control discs. Expression of the transferred gene was detected by staining with 5-bromo-4-chloro-3-indolyl-beta-galactosidase (X-Gal).

RESULTS

The in vitro experiments confirmed that nucleus pulposus cells were efficiently transduced by an adenoviral vector carrying the lacZ gene. In vivo injection of Ad-lacZ into the nucleus pulposus resulted in the transduction of a considerable number of cells. Marker gene expression in vivo persisted at an apparently undiminished level for at least 12 weeks. No staining was noted in control discs.

CONCLUSIONS

The results show the feasibility of adenovirus-mediated gene transfer to the intervertebral disc. Expression of the marker gene persisted at least 12 weeks in vivo. This successful demonstration of exogenous gene transfer to the disc and sustained, long-term expression suggests that the adenoviral vector may be suitable for delivery of appropriate genes to the disc for the treatment of spinal disorders.

Relationship between constitutive nitric oxide synthase activity and mucus level in the gastric mucosa of rats with stress

A decrease in constitutive nitric oxide synthase (cNOS) activity occurred with decreases in hexosamine (an index of mucus synthesis) and adherent mucus (an index of mucus secretion) concentrations in the gastric mucosa of rats with water immersion restraint (WIR) stress. The decreases in gastric mucosal hexosamine and adherent mucus concentrations were enhanced with a further decrease in gastric mucosal cNOS activity by pretreatment with NG-monomethyl L-arginine, a non-selective NOS inhibitor, but were prevented with maintenance of the gastric mucosal cNOS activity by pretreatment with aminoguanidine, a selective inducible NO synthase inhibitor. In all WIR-stressed rats used in this study, gastric mucosal cNOS activity was well correlated with either gastric mucosal hexosamine or adherent mucus concentration (r=0.717 or 0.739, respectively). These results indicate that in the gastric mucosa of WIR-stressed rats, a decrease in cNOS activity is closely related to a decrease in mucus level due to impairment of its synthesis and secretion. (c) 1998 The Italian Pharmacological Society.

Two distinct kerato-epithelin mutations in Reis-Bücklers corneal dystrophy

PURPOSE

Two patients were diagnosed with Reis-Bücklers corneal dystrophy (RBCD), although the pattern and severity of corneal opacification differed. To see whether there was a genetic basis for these phenotypic variations, we analyzed beta ig-h3, the gene that codes for kerato-epithelin and that contains a mutation (Arg555Gln) that causes RBCD.

METHODS

A 30-year-old man with honeycomb-shaped subepithelial opacities in his central cornea and a 25-year-old man with progressive subepithelial geographic opacities were both considered to have RBCD. We isolated genomic DNA from leukocytes of the two patients and their family members and screened for an Arg555Gln kerato-epithelin mutation. Then we analyzed all exons of the gene using the single-strand conformation polymorphism (SSCP) technique to search for any other kerato-epithelin mutations.

RESULTS

The patient with honeycomb-shaped opacities had an Arg555Gln kerato-epithelin mutation that caused his RBCD, whereas the patient with geographic opacities did not; instead, he had a new kerato-epithelin mutation (Arg124Leu), which cosegregated with his family members.

CONCLUSIONS

The variant of RBCD characterized by honeycomb-shaped opacities is caused by an Arg555Gln kerato-epithelin mutation. On the other hand, a new kerato-epithelin mutation, Arg124Leu, was found to cause the RBCD variant characterized by recurrent epithelial erosions and progressive geographic subepithelial opacification. Codon 124 is a hot spot for kerato-epithelin mutations, where the mutations responsible for three autosomal dominant corneal dystrophies--lattice type I (Arg124Cys), Avellino (Arg124His), and the variant of RBCD with geographic rather than honeycomb opacities (Arg124Leu)--are located.

Taurin-conjugated ursodeoxycholic acid has a reversible inhibitory effect on human keratinocyte growth

Tauroursodeoxycholic acid (TUDC) is one of the most hydrophilic taurin conjugated bile acids. TUDC has a suppressive effect on DNA synthesis in primary cultured rat hepatocytes. In this study, we investigated the growth inhibitory effect of TUDC on cultured human keratinocytes. TUDC suppressed the proliferation of keratinocytes in a dose dependent fashion, as measured by both cell counts and 5-bromo-2'-deoxyuridine (BrdU) uptake. Keratinocytes reproliferated and reached almost the same cell number as control after removal of TUDC from the medium. TUDC (1 mM) had no effect on the cell viability, as measured by the dye exclusion test. Epidermal sheets stratified in the presence of TUDC appeared thinner than those stratified without TUDC. These results suggest that TUDC has a reversible growth suppressive effect on human keratinocytes through the mechanism other than cytotoxicity and would be applicable for the treatment of hyperproliferative skin disorders such as psoriasis.

Isolation and characterization of human cathepsin V: a major proteinase in corneal epithelium

PURPOSE

To isolate and characterize a novel cathepsin gene, as part of the systematic isolation of genes uniquely active in corneal epithelium.

METHODS

For the isolation of a full-length cDNA clone, a probe was selected from a set of expressed sequence tag clones classified as unique to corneal epithelium. Inserted cDNA was introduced into insect cells using a baculovirus expression system, and the secretion of recombinant protein was identified using antisera against a synthetic peptide. Proteolytic activity was determined using bovine serum albumin (BSA) as substrate. The expressions of the novel cathepsin in human cornea and other tissues were examined by reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

The full-length cDNA clone encoded a peptide of 334 amino acids with 82% identity with bovine cathepsin L and 77% identity with human cathepsin L when aligned. The recombinant protein produced in the baculovirus expression system cleaves BSA, and its activity was inhibited by the cysteine proteinase inhibitors E-64 and leupeptin, but not by pepstatin A, phenylmethylsulfonyl fluoride, and EDTA. By RT-PCR, a low level of expression was observed in some other epithelial tissues of ectodermal origin, but only in cornea was it higher than cathepsin L, which is known to be a general lysosomal cathepsin. Cathepsin V protein was detected in human corneal epithelium by western blot analysis, but not in tear fluid.

CONCLUSIONS

The amino acid homology and proteolytic activity of the recombinant protein indicate that the novel gene is a new member of the cathepsins that have features of cysteine proteinase. Its uniquely high expression in corneal epithelium strongly implies an important role in corneal physiology.