Ocular and systemic features of Peters' anomaly.

BACKGROUND: To clarify the relationship between associated systemic anomalies and ocular manifestations in patients with Peters' anomaly, a retrospective study was conducted. METHODS: We classified 37 patients with Peters' anomaly into two groups, one with (+) and one without (-) systemic anomalies. RESULTS: The systemic anomaly (+) group consisted of 13 patients, eight males and five females, with mean age of 2.3 months. Peters' anomaly was bilateral in six cases and unilateral in seven. Corneolenticular adhesion was observed in 11 cases. Associated ocular anomalies were seen in 12 cases, and developmental glaucoma was present in eight cases. The systemic anomaly (-) group comprised 24 patients, 13 males and 11 females, with mean age of 28.3 months. Peters' anomaly was bilateral in 11 cases and unilateral in 13. Corneolenticular adhesion was observed in five cases. The associated ocular anomalies were observed in 10 cases, and developmental glaucoma was accompanied in six cases. The incidences of cases with corneolenticular adhesion, those with other ocular anomalies, and those with glaucoma were significantly higher in the systemic anomaly (+) group than in the systemic anomaly (-) group. CONCLUSIONS: Peters' anomaly accompanying corneolenticular adhesion and/or other ocular anomalies should be evaluated for the presence of systemic anomalies.

Chemical analysis of melanins and its application to the study of the regulation of melanogenesis.

Melanins are difficult to characterize because of their intractable chemical properties, the heterogeneity in their structural features, and the lack of methods to split melanin polymers into monomer units. To overcome this difficulty, we developed a rapid and sensitive method for quantitatively analyzing eumelanin and pheomelanin in biological samples that is based on the formation of pyrrole-2,3,5-tricarboxylic acid and/or aminohydroxyphenylalanine followed by HPLC determination. The method has been applied to the study of melanogenesis. The results summarized in this review are: 1) Biochemical studies show that in the process of mixed melanogenesis, cysteinyldopas are produced first, which are then oxidized to give pheomelanin; following cysteine depletion, eumelanin is then deposited on the preformed pheomelanin. 2) In vitro and in vivo studies show that tyrosinase activity is the most important factor that regulates the switch of melanogenesis, with lower tyrosinase activities favoring pheomelanogenesis; further suppression of melanogenesis results in a lack of pigment production. 3) In cultured melanocytes, the concentrations of tyrosine and cysteine, and their ratio in the medium, are important in determining the concentrations of eumelanin and pheomelanin produced and their ratio in the cells. In conclusion, our HPLC microanalytical method for characterizing eumelanin and pheomelanin has become a useful tool for the study of melanogenesis.

Anomalies associated with Axenfeld-Rieger syndrome.

BACKGROUND: To detect the associated anomalies in patients with Axenfeld-Rieger syndrome is clinically important, because early treatment for such anomalies is crucial to both visual and systemic development. This study was conducted to clarify the associated anomalies in the syndrome. METHODS: We evaluated 21 patients with Axenfeld-Rieger syndrome encountered at Nagoya City University Hospital over a 16-year period. Patients who presented with a prominent Schwalbe's line accompanying the iris strands were diagnosed as having Axenfeld-Rieger syndrome. RESULTS: The series consisted of 9 males and 12 females, ranging in age from 1 month to 41 years, mean 15.4+/-12.7 (SD) years. The syndrome was bilateral in 17 cases and unilateral in 4 cases. Hypoplasia of the iris was observed in 10 eyes of 6 patients. The associated ocular anomalies included sclerocornea in 6 eyes of 3 patients, developmental glaucoma in 5 eyes of 3 patients, persistent pupillary membrane in 4 eyes of 2 patients, microphthalmos in 3 eyes of 2 patients, and typical iris coloboma in 1 eye. Of 10 eyes with hypoplasia of the iris, 5 exhibited glaucoma. The accompanying systemic anomalies included 9 cases of dental anomalies, 5 of facial anomalies, and 3 of Alagille syndrome. CONCLUSIONS: All of the associated ocular and systemic anomalies appeared to arise from the maldevelopment of the neural crest cells. Patients with Axenfeld-Rieger syndrome should therefore be examined for the presence of anomalies in the tissues of neural crest origin. Patients with hypoplasia of the iris should be checked for glaucoma.

High-Resolution Terahertz Spectroscopy by a Compact Radiation Source Based on Photomixing with Diode Lasers in a Photoconductive Antenna

We demonstrate generation of continuous-wave terahertz radiation and its application to molecular spectroscopy. The radiation source is based on the photomixing of two diode laser beams in a low-temperature-grown GaAs photoconductive antenna, which offered output power of several tens of nanowatts at frequencies up to 2 THz with its long term frequency stability being about 5 MHz. The pure rotational spectra of CH3CN and isotopomers of CO were measured with this source, and 1% of absorption was clearly detected with a simple amplitude modulation technique. This indicates that the present system has a potential capability for high-resolution and high-sensitivity molecular spectroscopy. Copyright 1998 Academic Press. Copyright 1998Academic Press

[Four cases of persistent hyperplastic primary vitreous].

We evaluated four cases of persistent hyperplastic primary vitreous (PHPV) encountered at Nagoya City University Hospital in 1995. PHPV was seen unilaterally in three cases and bilaterally in one. The series comprised two males and two females, ranging in age from three to eight months, with an average of 4.8 months. Case 1 had a white strand running from the optic disc to the posterior surface of the lens in the left eye. Case 2 showed leukocoria in the right eye and central corneal opacity in the left. Magnetic resonance imaging (MRI) revealed total retinal detachment in both eyes. Case 3 exhibited retinal folds running from the optic disc to the posterior surface of the lens in the left eye. Case 4 showed elongation of the ciliary processes and leukocoria in the right eye. Ipsilateral total retinal detachment was seen in MRI. Three eyes of two cases were microphthalmic. Associated ocular anomalies included, posterior embryotoxon, sclerocornea, hypoplasia of the iris stroma and peripapillary staphyloma. There were accompanying systemic anomalies such as arachnoidal cyst, syndactyly, microcephalus, heart anomalies, pulmonary atresia and asplenia. Patients with PHPV should be carefully examined for the possible presence of other ocular and systemic anomalies caused by neural crest disorders.

Chemical characterization of pheomelanogenesis starting from dihydroxyphenylalanine or tyrosine and cysteine. Effects of tyrosinase and cysteine concentrations and reaction time.

Two types of melanin pigment are produced in mammals; the brown-to-black eumelanins and the yellow-to-reddish-brown pheomelanins. The switch from one type of melanin to the other appears to be regulated by the levels of tyrosinase and thiols, such as cysteine and glutathione. This study examines the process of pheomelanin formation starting from dihydroxyphenylalanine (dopa) or tyrosine and cysteine. We prepared pheomelanins by tyrosinase oxidation of dopa or tyrosine in the presence of cysteine. Experimental variables were reaction time, tyrosinase concentration, and dopa or tyrosine to cysteine ratio. Following the reactions, we measured concentrations of tyrosine, dopa, cysteine and cysteinyldopas, amounts of total melanin (TM) by Soluene-350 solubilization and aminohydroxyphenylalanine (AHP), a specific indicator of pheomelanin, formed by hydriodic acid hydrolysis, and absorbance ratio, A650/A500. It was found that (1) mixed melanogenesis is a heterogeneous process in which pheomelanogenesis proceeds first, followed by eumelanogenesis, as shown by changes in the tyrosine and cysteinyldopa concentrations, the AHP/TM ratio, and the A650/A500 ratio during the course of melanogenesis and (2) lower tyrosinase concentration favors pheomelanogenesis even when the availability of cysteine is limited, as shown by AHP/TM ratios that were higher than the corresponding tyrosine to cysteine ratios. These results indicate that the switch from eumelanogenesis to pheomelanogenesis can be achieved by lowering the tyrosinase activity, which conforms to our proposal that tyrosinase activity is the major factor controlling the course of melanogenesis.

Dihydro-1,4-benzothiazine-6,7-dione, the ultimate toxic metabolite of 4-S-cysteaminylphenol and 4-S-cysteaminylcatechol.

4-S-Cysteaminylphenol (4-S-CAP) and the corresponding catechol 4-S-cysteaminylcatechol (4-S-CAC) have been evaluated for melanocytotoxicity. It was shown recently that tyrosinase oxidation of these substrates produces a violet pigment, dihydro-1,4-benzothiazine-6,7-dione (BQ). In this study we examined whether BQ is the ultimate toxic metabolite produced in melanoma cells from 4-S-CAP/4-S-CAC. Biochemical experiments showed that (1) BQ was formed by autoxidation of 4-S-CAC as well as by tyrosinase oxidation of 4-S-CAP/4-S-CAC, (2) BQ reacted rapidly with thiols such as reduced glutathione (GSH), and (3) BQ inhibited the activity of alcohol dehydrogenase, an SH enzyme. In vitro experiments showed that (1) the cytotoxicity of 4-S-CAC was mostly prevented by catalase and superoxide dismutase, (2) BQ was highly cytotoxic to B16 melanoma cells (IC50 being 3.9 microM as compared with 507 microM for 4-S-CAP), (3) BQ was metabolized rapidly to a GSH adduct in melanoma cells, and (4) the same GSH adduct was also formed upon incubation of melanoma cells with 4-S-CAP, the reaction being tyrosinase dependent. In vivo experiments showed that intratumoral administration of BQ (0.5 micromol) inhibited the subcutaneous growth of B16 melanoma nearly as effectively as 4-S-CAP/4-S-CAC (20 micromol). These results indicate that BQ is the ultimate toxic metabolite produced by tyrosinase oxidation of 4-S-CAP/4-S-CAC. BQ deprives melanoma cells of GSH and may inactivate SH enzymes essential for DNA synthesis and cell proliferation by covalent binding through their cysteine residues, thereby exerting melanocytotoxicity. Cytotoxicity of 4-S-CAC depends mostly on autoxidation producing BQ and active oxygens.

Clinical evaluation of posterior embryotoxon in one institution.

To elucidate the pathogenesis of posterior embryotoxon, we estimated its incidence in our clinic and evaluated its associated ocular and systemic anomalies. Slit-lamp and gonioscopic examinations were performed on 440 randomly selected patients at Nagoya City University Hospital over a 10-month period. Posterior embryotoxon was detected in 107, 50 bilateral and 57 unilateral, cases (24.3%). Twelve (11.2%) of the 107 cases had open-angle glaucoma. Accompanying ocular anomalies included six cases of sclerocornea, two each of persistent pupillary membrane and familial exudative vitreoretinopathy, and 1 each of melanocytoma of the optic nervehead, choroidal nevus and subconjunctival dermoid cyst. Associated systemic anomalies included three cases of Alagille syndrome, two of congenital biliary atresia, and one each of congenital facial palsy with microtia, congenital adrenal hyperplasia, empty sella syndrome, Hirschsprung disease and Wilson disease. Many of these ocular and systemic anomalies were caused by the maldevelopment of neural crest cells. Patients with posterior embryotoxon should be examined for the possible presence of open-angle glucoma and for ocular and systemic anomalies related to maldevelopment of neural crest cells.

[A case of nonrhegmatogenous retinal detachment in Dandy-Walker Syndrome].

A 2-month-old female presented with nonrhegmatogenous retinal detachment in Dandy-Walker syndrome. At the fist examination, coloboma involving the optic disc in both eyes was detected. The left eye showed microphthalmos with sclerocornea, persistent pupillary membrane, hypoplasia of the iris stroma, and bullous retinal detachment near the optic disc. Chromosomal analysis revealed a mosaic pattern: 46, XX/47, XXX. Increased intracranial pressure associated with Dandy-Walker syndrome was detected by a neurosurgeon at the age of 3 months. The patient was followed for several weeks, and then nonrhegmatogenous retinal detachment appeared in the right eye. Subretinal fluid alternately increased and decreased in both eyes. A ventriculo-peritoneal shunt was performed at the age of 6 months, and the retinal detachment was remarkably reduced in both eyes after lowering of intracranial pressure. Coloboma involving the optic disc, sclerocornea, persistent pupillary membrane, hypoplasia of iris stroma, and Dandy-Walker syndrome were thought to be caused by the abnormal development of neural crest cells. We surmised that the retinal detachment in this case might have resulted from a communicating pathway between the subarachnoid space and the subretinal space. We concluded that the etiology of retinal detachment associated with optic disc anomaly should be investigated to determine adequate treatment.

Antimelanoma effect of 4-S-cysteaminylcatechol, an activated form of 4-S-cysteaminylphenol.

Rational chemotherapy of malignant melanoma could be developed by taking advantage of the presence of melanogenic enzymes in melanoma cells. 4-S-Cysteaminylphenol (4-S-CAP) has been evaluated for melanocytotoxicity and antimelanoma effect. Although 4-S-CAP is selectively toxic to pigmented melanoma cells, it is not potent enough when applied as a single agent. To increase the efficacy of 4-S-CAP, we synthesized 4-S-cysteaminylcatechol (4-S-CAC), an activated form of 4-S-CAP, and compared its biochemical properties and antimelanoma effects with those of the isomers 3-S-cysteaminylcatechol (3-S-CAC) and 2-S-cysteaminyl-hydroquinone (2-S-CAH). 4-S-CAC was found to be a better substrate for melanoma tyrosinase than was L-3,4-dihydroxyphenylalanine, the natural catecholic substrate. 3-S-CAC was a poor substrate, whereas 2-S-CAH was not a substrate. 4-S-CAC was the most cytotoxic to three lines of melanoma cells in vitro, followed by 2-S-CAH and 3-S-CAC. When applied i.p. for 9 days at a dose of 100 mg/kg, 4-S-CAC.HCl, increased by 46-52% the life span of C57BL/6 mice inoculated i.p. with B16 melanoma; this effect was comparable to that of a 50 mg/kg dose of 5-(3,3-dimethyltriazenyl)-1H-imidazole-4-carboxamide. 3-S-CAC was marginally effective, whereas 2-S-CAH was toxic to the host. This systemic toxicity of 2-S-CAH reflected its susceptibility to autoxidation. Growth of B16 melanoma cells inoculated s.c. was significantly inhibited by i.p. administration of 4-S-CAC.HCl (200 mg/kg) for 5 days (P < 0.05). These results suggest that 4-S-CAC is a potent antimelanoma agent, the effect of which is mostly mediated through tyrosinase oxidation.

Spectrophotometric assay of eumelanin in tissue samples.

Most of the natural melanin pigments consist of not only indolic eumelanin but also sulfur-containing pheomelanin. Previous methods for spectrophotometric assay of melanins use solubilization in alkaline media; a major disadvantage of these procedures is that they do not distinguish between eumelanin and pheomelanin. A spectrophotometric method for assaying eumelanin in tissue samples is described. Sepia melanin serves as a standard. Hair and melanoma samples were hydrolyzed in hot hydriodic acid, and insoluble eumelanic pigments were solubilized in hot sodium hydroxide in the presence of hydrogen peroxide and analyzed for absorbance at 350 nm (A350). The detection limit of eumelanin was ca. 2 micrograms. Eumelanins prepared from dopa, 5,6-dihydroxyindole and its carboxy derivative gave similar A350 values. Mixed-type melanins prepared from dopa and various ratios of cysteine gave A350 values inversely proportional to their sulfur contents. Excellent correlations were observed between A350 values and contents of pyrrole-2,3,5-tricarboxylic acid, an oxidation product specific for eumelanin, in hair samples from sheep and humans of various colors and in melanomas and eyes from mice. The present method provides a specific and direct measurement of eumelanin contents in tissue samples.

Identification of a novel nifH-like (frxC) protein in chloroplasts of the liverwort Marchantia polymorpha.

The frxC gene, one of the unidentified open reading frames present in liverwort chloroplast DNA, shows significant homology with the nifH genes coding for the Fe protein, a component of the nitrogenase complex (Ohyama et al., 1986, Nature 322: 572-574). A truncated form of the frxC gene was designed to be over-expressed in Escherichia coli and an antibody against this protein was prepared using the purified product as an antigen. This antibody reacted with a protein in the soluble fraction of liverwort chloroplasts, which had an apparent molecular weight of 31,000, as revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, in good agreement with a putative molecular weight of 31,945 deduced from the DNA sequence of the frxC gene. In a competitive inhibition experiment, the antigenicity of this protein was indicated to be similar to that of the over-expressed protein in E. coli. Therefore, we concluded that the frxC gene was expressed in liverwort chloroplasts and that its product existed in a soluble form. The molecular weight of the frxC protein was approximately 67,000, as estimated by gel filtration chromatography, indicating that the frxC protein may exist as a dimer of two identical polypeptides analogous to the Fe protein of nitrogenase. The results obtained from affinity chromatography supported the possibility that the frxC protein, which possesses a ATP-binding sequence in its N-terminal region that is conserved among various other ATP-binding proteins, has the ability to bind ATP.

[Combined valvular and coronary artery surgery].

Combined valvular and coronary surgery were performed on 9 patients between 1973 and 1986. Valve replacements were consist of 5 AVR (including 1 translocated AVR and 1 Bentall operation), 2 MVR and 2 double valve replacement. Coronary surgery were of 6 aorto-coronary bypass using great saphenous veins, 1 innominate artery-coronary bypass using a Dacron prosthesis, 1 punch-out of coronary ostium and 1 dilatation of the left coronary ostium with a vein patch. Retrograde infusion of cardioplegic solution from the coronary sinus were done in patients with coronary ostial stenoses. One emergency case with acute cardiac failure died immediately after operation, and one with double valve and one with mitral valve replacement died of hepatic failure and multiple organ failure respectively within 1 year after surgery. Combined valvular and coronary surgery are necessary for patients with both diseases. Although the results of double valve replacement were not satisfactory, they would be improved using intra-aortic balloon pump and ventricular assist devices actively.

Phase I and pharmacokinetic study of SM-5887, a new anthracycline derivative.

SM-5887, a new totally synthetic anthracycline derivative was studied in a phase I setting. Twenty-nine evaluable courses of treatment were conducted in groups at doses increasing from 10 to 130 mg/m2. Myelosuppression was the dose-limiting toxicity and a MTD was 130 mg/m2. At 130 mg/m2 the median lowest white blood cell count was 0.7 x 10(3)/cmm (range: 0.3-1.8) and the median lowest granulocyte count was 0.1 x 10(3)/cmm (range: 0-0.7) and the median lowest platelet count was 57 x 10(3)/cmm (range: 4-176). Non-hematologic side effects were mild gastrointestinal symptoms and hair loss. The recommended dose and schedule for phase II setting is 100 mg/m2 every 3 weeks.

Replacement of myocardium with a Dacron prosthesis for complications of acute myocardial infarction.

From July 1983 to April 1986, four patients (three with ventricular septal perforations and one with left ventricular free-wall rupture) underwent replacement of the myocardium with a Dacron prosthesis for complications of acute myocardial infarction. There were three males and one female, ages ranging from 53 to 70 years (mean 63.3). Three of the four patients survived; the one with the ventricular septal perforation died of severe cardiac failure five days after operation. Replacement of the infarcted myocardium with a Dacron prosthesis seems to be an excellent operative technique for the treatment of complications of acute myocardial infarction when the left ventricular cavity is predicted to be small after resection of the myocardium.

A nicked group II intron and trans-splicing in liverwort, Marchantia polymorpha, chloroplasts.

The chloroplast gene rps12 for ribosomal protein S12 in a liverwort, Marchantia polymorpha, is split into three exons by two introns, one of which (intron 1) is discontinuous. Exon 1 of rps12 for the N-terminal portion of the S12 protein is far from exons 2 and 3 for the C-terminal portion on the opposite DNA strand. S1-nuclease protection analysis and Northern hybridization with RNA isolated from the liverwort chloroplasts showed that: (i) the exons 1 and 2-3 of the rps12 gene with the neighboring genes were transcribed separately, (ii) the trans-splicing of intron 1 occurred after the processing of two primary transcripts to two pre-mRNAs, and (iii) there was no particular order for the splicing of intron 1 (trans) and intron 2 (cis) in the rps12 gene. We propose a bimolecular interaction model for trans-splicing by assuming that intermolecular base pairings between two pre-mRNAs result in the formation of the structure typical of group II introns except for disruption in the loop III region. This structure could be constructed in intron 1 of tobacco rps12 gene.

Structure and organization of Marchantia polymorpha chloroplast genome. II. Gene organization of the large single copy region from rps'12 to atpB.

The nucleotide sequence (56,410 base-pairs) of the large single-copy region of chloroplast DNA from the liverwort Marchantia polymorpha has been determined. The sequence starts from one end (JLA) of the large single-copy region and encompasses genes for 21 tRNAs, six ATPase subunits (atpA, atpB, atpE, atpF, atpH and atpI), two photosystem I polypeptides (psaA and psaB), four photosystem II polypeptides (psbA, psbC, psbD and psbG), five ribosomal proteins (rps2, rps4, rps7, rps'12 and rps14), and three RNA polymerase subunits (rpoB, rpoC1 and rpoC2). In addition, we detected 18 open reading frames ranging from 29 to 2136 amino acid residues long, four of which share significant amino acid sequence homology to those of an Escherichia coli malK protein (designated mbpX), human mitochondrial ND2 (ndh2) and ND3 (ndh3) of a respiratory chain NADH dehydrogenase, or a bacterial antenna protein of a light-harvesting complex (lhcA). Sequence analysis suggests that four tRNA genes and six protein genes might be split by introns; they are trnG(UCC), trnK(UUU), trnL(UAA), trnV(UAC), atpF, ndh2, rpoC1, rps'12, ORF135 and ORF167. In the large single-copy region described here, the gene organization deduced is highly conserved with respect to that of higher plants, but an inversion of some 30,000 base-pairs flanked by trnL(CAA) and trnD(GUC) was seen between the liverwort and tobacco chloroplast genomes.

Structure and organization of Marchantia polymorpha chloroplast genome. III. Gene organization of the large single copy region from rbcL to trnI(CAU).

The nucleotide sequence (25,320 base-pairs) of a part of the large single-copy region of chloroplast DNA from the liverwort Marchantia polymorpha was determined. This region encodes putative genes for four tRNAs, isoleucine tRNA(CAU), arginine tRNA(CCG), proline tRNA(UGG) and tryptophan tRNA(CCA); eight photosynthetic polypeptides, the large subunit of ribulose bisphosphate carboxylase/oxygenase (rbcL), 51,000 Mr photosystem II chlorophyll alpha apoprotein (psbB), apocytochrome b-559 polypeptides (psbE and psbF), 10,000 Mr phosphoprotein (psbH), cytochrome f preprotein (petA), cytochrome b6 polypeptide (petB), and cytochrome b6/f complex subunit 4 polypeptide (petD); 13 ribosomal proteins (L2, L14, L16, L20, L22, L23, L33, S3, S8, S11, S12, S18 and S19); initiation factor 1 (infA); ribosome-associating polypeptide (secX); and alpha subunit of RNA polymerase (rpoA). Functionally related genes were located in several clusters in this region of the genome. There were two ribosomal protein gene clusters: rpl23-rpl2-rps19-rpl22-rps3-rpl16-+ ++rpl14-rps8-infA-secX-rps11-rpoA, with a gene arrangement similar to that of the Escherichia coli S10-spc-alpha operons, and the rps12'-rpl20-rps18-rpl33 cluster. There were gene clusters encoding photosynthesis components such as the psbB-psbH-petB-petD and the psbE-psbF clusters. Thirteen open reading frames, ranging in length from 31 to 434 amino acid residues, remain to be identified.