Systemic circulatory parameters. comparison between patients with normal tension glaucoma and normal subjects using ambulatory monitoring

PURPOSE

To compare circadian changes of systemic circulation in patients with normal tension glaucoma (NTG) and normal subjects.

METHODS

Forty-three patients with NTG and 226 normal subjects were enrolled in this study. Circulatory parameters, including blood pressure (BP) and pulse rate (PR), were measured in all subjects for 49 hours using an ambulatory monitoring system. In addition to a comparison between NTG patients and normal controls, the same parameters were compared between NTG patients who had progressive field defects and NTG patients who had stable field defects.

RESULTS

The BP in NTG patients was significantly higher than in normal subjects. The nocturnal dip of BP in NTG patients was similar to the dip in normal subjects. However, the BP dip in NTG patients showing progressive visual field defects was significantly smaller than in patients with NTG showing stable visual field defects. Blood pressure fluctuation in sleep in the "progressive" patients was significantly greater than in the "stable" patients. Patients with NTG whose random BP was in a normal range showed a higher BP than normal subjects. The dip in PR in NTG patients was significantly lower than in normal subjects.

CONCLUSIONS

An insufficient physiological nocturnal BP dip or a greater nocturnal fluctuation in BP may disturb the microcirculation of, and/or may directly damage, the optic nerve, resulting in increasing field loss in NTG.

Efficacy of treatment with chimeric monoclonal antibody (Infliximab) to tumor necrosis factor-alpha for Crohn's disease in Japan: evaluation by rapid turnover proteins, and radiologic and endoscopic findings

BACKGROUND

Several studies have reported that the chimeric monoclonal antibody to tumor necrosis factor (TNF)-alpha (Infliximab) is extremely valuable in the treatment of Crohn's disease. The aim of this study was to clarify the efficacy of this treatment in Japanese patients with Crohn's disease.

METHODS

A 12-week multicenter, open trial of Infliximab was carried out and involved 25 patients with moderate to severe Crohn's disease who were resistant to conventional treatment. Patients received a single 2-h intravenous infusion of Infliximab at a dose of 1, 3, 5 or 10 mg/kg bodyweight. Clinical evaluation of this treatment response was defined as a reduction in the index of the inflammatory bowel disease (IOIBD) and of the Crohn's disease activity index scores (CDAI), and in serum levels of C-reactive protein (CRP) at 2, 4, 8 and 12 weeks, and as an increase in serum levels of rapid turnover proteins as well as improvement of radiologic and endoscopic findings at 4 weeks.

RESULTS

The IOIBD score was reduced after 4 weeks in 66.7% of the group receiving 1 mg/kg Infliximab, 71.4% in the group receiving 3 mg/kg, 80.0% in the group receiving 5 mg/kg, and 85.7% in the group receiving 10 mg/kg. Improvement was better maintained over 12 weeks in the 5 and 10 mg/kg groups compared with the 1 and 3 mg/kg groups. Similar results were obtained for the CDAI scores. Serum levels of rapid turnover proteins significantly increased to within the normal ranges after infusion in all groups. Seven of the 11 (63.6%) patients evaluated showed improvement of radiologic and endoscopic findings.

CONCLUSIONS

A single infusion of Infliximab was effective for the treatment of Japanese patients with Crohn's disease. Serum rapid turnover proteins reflected the clinical response to antibody for TNF-alpha well.

Effects of Isopropyl Unoprostone on Melanogenesis in Mouse Epidermal Melanocytes

PURPOSE

To investigate the effects of isopropyl unoprostone (referred to as unoprostone) on melanin synthesis and the nature of melanin.

METHODS

M1 and M2, potential intraocular oxidized metabolites of unoprostone, were added to the culture medium in a cultured immortal line of mouse epidermal melanocytes, melan-a, once a day for 2 weeks at concentrations of 5 nM and 50 nM. Vehicle solution was utilized as a control. The amounts of pyrrole-2,3,5-tricarboxylic acid (PTCA), an oxidized product of eumelanin, and aminohydroxyphenylalanine (AHP), a hydrolyzed product of pheomelanin, were measured by high-performance liquid chromatography.

RESULTS

A 5-nM concentration of M2 significantly increased PTCA production (20.84 +/- 3.17 ng/10(6) cells mean +/- SD) compared with the control (14.58 +/- 4.62 ng/10(6) cells) (P =.04), although other concentrations did not affect the synthesis of PTCA or AHP. A 5-nM concentration of M2 significantly increased the PTCA/AHP (1.86 +/- 0.18) ratio compared with the control (1.37 +/- 0.41) (P =.04). A 50 nM concentration of M2 slightly increased the PTCA/AHP (1.74 +/- 0.58) ratio, but M1 did not affect this ratio.

CONCLUSIONS

These results indicate that M2 affects not only melanogenesis but also the nature of melanin, which could result in unoprostone-generated iridial pigmentation.

Cystoid macular edema associated with topical latanoprost in glaucomatous eyes with a normally functioning blood-ocular barrier

PURPOSE

To study prospectively using optical coherence tomography (OCT) whether topical latanoprost induces retinal disorders, such as cystoid macular edema, in patients with glaucoma and a normally functioning blood-ocular barrier.

METHODS

Sixty-eight eyes of 38 patients with glaucoma and no history of intraocular surgery, uveitis, or laser trabeculoplasty were studied. Before initiation of latanoprost treatment and after 1, 3, and 6 months of treatment, OCT images were taken, and the following tests were performed: visual acuity examination, fundus ophthalmoscopy, intraocular pressure measurement, and fundus color photography. To evaluate retinal thickness in the fovea accurately. OCT scanning was repeated six times, and the smallest value was used as the retinal thickness in the fovea.

RESULTS

Latanoprost ophthalmic solution did not influence retinal thickness in the fovea at any investigated time points compared with the time before instillation, and no changes were observed in visual acuity, ophthalmoscopic findings, and fundus photographs. The intraocular pressure was reduced significantly at all investigated time points compared with the time before instillation.

CONCLUSIONS

It is unlikely that topical latanoprost induces retinal disorders, such as cystoid macular edema, in glaucomatous eyes with a normally functioning blood-ocular barrier.

Polyamine enhancement of the synthesis of adenylate cyclase at the translational level and the consequential stimulation of the synthesis of the RNA polymerase sigma 28 subunit

The effects of polyamines on the synthesis of various final sigma subunits of RNA polymerase were studied using Western blot analysis. Synthesis of final sigma(28) was stimulated 4.0-fold and that of final sigma(38) was stimulated 2.3-fold by polyamines, whereas synthesis of other final sigma subunits was not influenced by polyamines. Stimulation of final sigma(28) synthesis was due to an increase in the level of cAMP, which occurred through polyamine stimulation of the synthesis of adenylate cyclase at the level of translation. Polyamines were found to increase the translation of adenylate cyclase mRNA by facilitating the UUG codon-dependent initiation. Analysis of RNA secondary structure suggests that exposure of the Shine-Dalgarno sequence of mRNA is a prerequisite for polyamine stimulation of the UUG codon-dependent initiation.

Effects of isopropyl unoprostone ophthalmic solution on cultured rabbit corneal epithelial cells

PURPOSE

To investigate the effects of isopropyl unoprostone (referred to as unoprostone) ophthalmic solution on the barrier function of cultured rabbit corneal epithelium grown on permeable supports.

METHODS

Rabbit corneal epithelial cells cultured on collagen-coated filter inserts were administered one of the following for 30 min: unoprostone in vehicle solution (polysorbate 80), unoprostone in vehicle solution with a preservative (benzalkonium chloride), preservative only or vehicle only. For a control, no chemicals were added to the medium. After administration, the transepithelial electrical resistance (TER) measurement, a sensitive method by which to investigate the barrier function, and morphological observation using phase-contrast microscopy were performed before exposure and at 0.5, 1, 3, 6, 12, 24, 48 and 72 h after exposure. The transmission electron-microscopic observation was performed before and 72 h after exposure in all experimental conditions.

RESULTS

The cells exposed to unoprostone with the preservative showed a significant decrease in the TER, although no morphological changes were observed. The corneal epithelial cells exposed to unoprostone without preservative, the vehicle only or the preservative only did not show any differences from the control group at any measurements.

CONCLUSION

The corneal barrier function is damaged by a combined solution of unoprostone and preservative, but not by a single solution of unoprostone, in vitro.

A sequence change (Arg158Gln) in the leucine zipper-like motif region of the MYOC/TIGR protein

The myocilin/trabecular meshwork-inducible glucocorticoid response (MYOC/TIGR) gene was identified as a gene that caused open angle glaucoma (OAG). Single-strand conformation polymorphism analysis and subsequent sequence analysis were performed for the MYOC/TIGR gene in 120 unrelated Japanese OAG patients with increased intraocular pressure (IOP), 116 unrelated OAG patients without increased IOP, and 106 unrelated control subjects without glaucoma. An Arg158Gln sequence change in the leucine zipper-like motif (LZM) region in the myosin-homology domain was found in 2 OAG patients with or without increased IOP, and in a 56-year-old control subject without glaucoma. This is the first report of missense sequence change in the LZM region of the MYOC/TIGR protein in subjects showing various phenotypes, including a control subject. These findings suggest that Arg158Gln in the LZM region is probably a rare nondisease-causing polymorphism, despite its important role in this region, because it was found in a control subject, although Arg158Gln was previously reported as a probable disease-causing mutation.

Matrix metalloproteinases in human diabetic and nondiabetic vitreous

PURPOSE

To compare matrix metalloproteinase (MMP) activities in human vitreous samples from patients with diabetic retinopathy (DR) and other vitreoretinal diseases, and to investigate the factors influencing the MMP activities in human DR vitreous samples.

METHODS

Thirty-one diabetic and 17 nondiabetic vitreous samples (from nine patients with macular holes and eight patients with epiretinal membranes) were examined. Samples collected at the time of pars plana vitrectomy were subjected to substrate zymography to conduct a quantitative analysis of MMP activity. Immunoblotting against antihuman MMP-1, 2, and 9 was performed to identify MMP in vitreous samples. The effects of posterior vitreous detachment (PVD), vitreous hemorrhage, proliferative membrane, traction detachment, and cystoid macular edema on MMP activities were investigated.

RESULTS

All vitreous samples from both DR and non-DR patients showed a single band at the position of 72 kD, corresponding to MMP-2. Another band at 99 kD, corresponding to MMP-9, was detected significantly more often in DR samples than in non-DR samples: 45.2% and 0%, respectively (P = 0.0007). The number of samples showing a band from MMP-9 was significantly higher in partial PVD samples than in complete PVD samples: 66.7% and 15.4%, respectively (P = 0.001).

CONCLUSION

The results indicated that MMP-9 may be involved in DR and that partial PVD may be related to the MMP-9 activity in DR.

Polyamine uptake systems in Escherichia coli

The polyamine content of cells is regulated by biosynthesis, degradation, and transport. In Escherichia coli, the genes for three different polyamine transport systems have been cloned and characterized. Two uptake systems (putrescine-specific and spermidine-preferential) are ABC transporters, each consisting of a periplasmic substrate binding protein, two transmembrane proteins, and a membrane-associated ATPase. The third transport system, catalyzed by PotE, mediates both uptake and excretion of putrescine. In this article, the properties of the first two polyamine uptake systems are reviewed in detail.

Analysis of myocilin gene mutations in Japanese patients with normal tension glaucoma and primary open-angle glaucoma

The myocilin gene was identified as a gene (MYOC) that caused primary open-angle glaucoma (POAG). Although a normal tension glaucoma (NTG) patient with the myocilin gene mutation was previously reported, no study using large numbers of patients with NTG has been reported. Single-strand conformation polymorphism analysis and subsequent sequence analysis were performed for genotyping the myocilin gene in 114 unrelated Japanese patients with NTG. One hundred and nineteen patients with POAG and 100 control subjects without glaucoma were studied as reference subjects. Five amino acid sequence changes of the myocilin were identified: Arg46Stop (one NTG), Arg76Lys (four NTG, 10 POAG, seven control), Arg158Gln (one NTG, one POAG, one control) found in only Japanese, Asp208Glu (four NTG, three POAG, one control), Pro481Ser (one control). Pro481Ser was novel. Arg76Lys always occurred with 1-83 from G to A in the promoter as it was reported in Chinese. Although some Japanese patients with NTG had sequence changes of the myocilin gene, there were no apparent specific mutations in patients with NTG.

Polyamine cytotoxicity in the presence of bovine serum amine oxidase

The toxicity of extracellular spermine, determined in the presence of fetal calf serum, was studied using three cell lines: FM3A, L1210, and NIH3T3 cells. Amine oxidase in fetal calf serum produces aminodialdehyde generating acrolein spontaneously, H(2)O(2), and ammonia from spermine. Spermine toxicity was prevented by aldehyde dehydrogenase, but not by catalase. Similar concentrations of spermine and acrolein were needed to produce toxicity. Other aldehydes (formaldehyde, acetaldehyde, and propionaldehyde) and hydrogen peroxide were less toxic than acrolein. Spermidine and 3-aminopropanal, which produces acrolein, also exhibited severe cytotoxicity. The degree of cytotoxicity of spermine, spermidine, and 3-aminopropanal was nearly parallel with the amount of acrolein produced from each compound. Thus, it was deduced that acrolein is a major toxic compound produced from polyamines (spermine and spermidine) by amine oxidase.

Multiple polyamine transport systems on the vacuolar membrane in yeast

We recently identified a gene (TPO1, YLL028w) that encodes a polyamine transport protein on the vacuolar membrane in yeast [Tomitori, Kashiwagi, Sakata, Kakinuma and Igarashi (1999) J. Biol. Chem. 274, 3265-3267]. Because the existence of one or more other genes for a polyamine transport protein on the vacuolar membrane was expected, we searched sequence databases for homologues of the protein encoded by TPO1. Membrane proteins encoded by the open reading frames YGR138c (TPO2), YPR156c (TPO3) and YOR273c (TPO4) were postulated to be polyamine transporters and, indeed, were subsequently shown to be polyamine transport proteins on the vacuolar membrane. Cells overexpressing these genes were resistant to polyamine toxicity and showed an increase in polyamine uptake activity and polyamine content in vacuoles. Furthermore, cells in which these genes were disrupted showed an increased sensitivity to polyamine toxicity and a decrease in polyamine uptake activity and polyamine content in vacuoles. Resistance to polyamine toxicity in cells overexpressing the genes was overcome by bafilomycin A(1), an inhibitor of the vacuolar H(+)-ATPase. Among the four polyamine transporters, those encoded by TPO2 and TPO3 were specific for spermine, whereas those encoded by TPO1 and TPO4 recognized spermidine and spermine. These results suggest that polyamine content in the cytoplasm of yeast is elaborately regulated by several polyamine transport systems in vacuoles. Furthermore, it was shown that Glu-207, Glu-324 (or Glu-323) and Glu-574 of TPO1 protein were important for the transport activity.

Identification of the putrescine recognition site on polyamine transport protein PotE

The PotE protein can catalyze both uptake and excretion of putrescine. The K(m) values of putrescine for uptake and excretion are 1.8 and 73 microm, respectively. Uptake of putrescine is dependent on the membrane potential, whereas excretion involves putrescine-ornithine antiporter activity. Amino acids involved in both activities were identified using mutated PotE proteins. It was found that Cys(62), Trp(201), Trp(292), and Tyr(425) were strongly involved in both activities, and that Tyr(92), Cys(210), Cys(285), and Cys(286) were moderately involved in the activities. Mutations of Tyr(78), Trp(90), and Trp(422) mainly affected uptake activity, and the K(m) values for putrescine uptake by these PotE mutants increased greatly, indicating that these amino acids are involved in the high affinity uptake of putrescine by PotE. Mutations of Lys(301) and Tyr(308) mainly affected excretion activity (putrescine-ornithine antiporter activity), and excretion by these mutants was not stimulated by ornithine, indicating that these amino acids are involved in the recognition of ornithine. It was found that the putrescine and ornithine recognition site on PotE is located at the cytoplasmic surface and the vestibule of the pore consisting of 12 transmembrane segments. Based on the results of competition experiments with various putrescine analogues and the disulfide cross-linking of PotE between cytoplasmic loops and the COOH terminus, a model of the putrescine recognition site on PotE consisting of the identified amino acids is presented.

Dystrobrevin localization in photoreceptor axon terminals and at blood-ocular barrier sites

PURPOSE

Dystrobrevin is a newly discovered dystrophin-associated protein with multiple sites for phosphorylation on tyrosine residues. In the present study, the cellular distribution and subcellular localization of dystrobrevin were examined in the adult rat retina, cornea, lens, iris, ciliary body, and cultured Müller cells.

METHODS

Immunoblot analysis, confocal laser scanning microscopy, and immunoelectron microscopy were used to examine dystrobrevin expression.

RESULTS

Immunoblot analysis showed that an approximately 87-kDa band was expressed predominantly in the lens, retina, iris and ciliary body, whereas an approximately 60-kDa band was expressed in cultured Müller cells, cornea, retina, iris, and ciliary body. Confocal microscopy demonstrated dystrobrevin in the inner limiting membrane, outer plexiform layer, and retinal pigment epithelium and around blood vessels in the retina. At the ultrastructural level, dystrobrevin was localized under cell membranes of rod spherules and cone pedicles of photoreceptor cell terminals but often was found in the cytoplasm of endothelial cells and Müller cells. Furthermore, dystrobrevin was colocalized with beta-dystroglycan in corneal endothelium; lens, iris, and ciliary epithelia; and cultured Müller cells.

CONCLUSIONS

The present study demonstrates that dystrobrevin is expressed in neurons, glia, and endothelial cells in the rat retina. In addition, dystrobrevin is localized at the blood-ocular barrier sites in extraocular tissue. These data suggest that dystrobrevin plays an important role in visual function.

Detection of HIV-RNA in aqueous humor and subretinal fluid in an HIV carrier with rhegmatogenous retinal detachment

BACKGROUND

Although human immunodeficiency virus (HIV)-related ocular complexes are commonly observed in acquired immune deficiency syndrome (AIDS) patients, it has not been previously reported that HIV had already invaded the ocular tissues of HIV carriers.

CASE

A 56-year-old woman was diagnosed as having rhegmatogenous retinal detachment with a retinal tear in the 6-o'clock position in her right eye. No signs of ocular manifestations except the retinal detachment were observed. A blood examination revealed that she was already infected with HIV-1, and she was categorized as an HIV carrier.

OBSERVATIONS

Aqueous humor and subretinal fluid samples were obtained at the time of surgery for rhegmatogenous retinal detachment. Reverse-transcription polymerase chain reaction and Southern blotting at three regions of the HIV, LTR, gag, and env, confirmed the HIV infection in both aqueous humor and subretinal fluid. During the approximately 2-year follow-up after surgery, the patient did not show any signs of retinitis, uveitis, or other ocular manifestations.

CONCLUSIONS

This is the first report to reveal that HIV can invade the eye in the early stage of HIV infection. This infection may be related to HIV-related ocular complexes, which suppress the local immunological response.

Antioxidative galloyl esters as enzyme inhibitors of p-hydroxybenzoate hydroxylase

Gallic acid and its esters were evaluated as enzyme inhibitors of recombinant p-hydroxybenzoate hydroxylase (PHBH), a NADPH-dependent flavin monooxygenase from Pseudomonas aeruginosa. n-Dodecyl gallate (DG) (IC(50)=16 microM) and (-)-epigallocatechin-3-O-gallate (EGCG) (IC(50)=16 microM), a major component of green tea polyphenols, showed the most potent inhibition, while product-like gallic acid did not inhibit the enzyme significantly (IC(50)>250 microM). Inhibition kinetics revealed that both DG and EGCG inhibited PHBH in a non-competitive manner (K(I)=18.1 and 14.0 microM, respectively). The enzyme inhibition was caused by specific binding of the antioxidative gallate to the enzyme, and by scavenging reactive oxygen species required for the monooxygenase reaction. Molecular modeling predicted that EGCG binds to the enzyme in the proximity of the FAD binding site via formation of three hydrogen bonds.

Increase in cap- and IRES-dependent protein synthesis by overproduction of translation initiation factor eIF4G

The role of eIF4G during the initiation of protein synthesis was studied using mouse mammary carcinoma FM3A cells and FM4G cells that overproduce an N-terminally truncated form of eIF4G, which lacks the binding site of poly(A)-binding protein. An increase in eIF4G was correlated with an increase in protein synthesis and RNA helicase activity. Translation of mRNAshaving both short and long 5'-untranslated regions (5'-UTR) increased significantly in FM4G cells compared to that in FM3A cells. Both full-length and N-terminally truncated eIF4G transfectants of NIH3T3 cells formed colonies in soft agar and increased the saturation density of cell growth, indicating that both eIF4Gs function similarly. We also found that an internal ribosome entry site (IRES) exists in the 5'-UTR of ornithinedecarboxylase mRNA and that IRES-dependent protein synthesis increased in FM4G cells. Our results indicate that an increase in eIF4G contributes to the formation of active eIF4F similarly to that caused by an increase in eIF4E, as well as to a stimulation of IRES-dependent protein synthesis.

Human CD8 and CD4 T cell epitopes of epithelial cancer antigens

Recent human tumor immunology research has identified several genes coding immunogenic peptides recognized by CD8 cytotoxic T lymphocytes (CTLs) in melanoma tumors. Very recently, CD4 T cell antigenic epitopes were also determined in certain melanoma tumors. The use of these peptides in conjunction with human immunotherapy could prove to be of great benefit. However, such peptides in clinically common tumors of epithelial cell origin, such as of the stomach, colon, lung, etc., have not yet been determined extensively. We describe for the first time an HLA-A31 (A*31012)-restricted natural antigenic peptide recognized by the CD8 CTL TcHST-2 of gastric signet ring cell carcinoma cell line HST-2. We also identified the HLA-DRB1*08032-restricted peptide recognized by the CD4 T cell line TcOSC-20 of squamous cell carcinoma OSC-20 derived from the oral cavity. The antigenic peptide of HST-2, designated F4.2, is composed of 10 amino acid residues with two anchor motif residues necessary for binding to HLA-A31 molecules. The synthetic F4.2 peptide enhanced the reactivity of TcHST-2 against HST-2 cells. Furthermore, introduction of an expression minigene coding F4.2 peptide to HLA-A31(+) cells conferred cytotoxic susceptibility to TcHST-2 on the cells. Some stomach cancer lines into which the HLA-A31 gene had been introduced, such as MKN28-A31-2, were lysed by TcHST-2, suggesting the presence of F4.2 peptide in at least some HLA-A31(+) stomach cancers. Furthermore, F4.2 peptide induced an F4.2 peptide-specific CTL response in at least 30-40% of HLA-A31(+) peripheral blood lymphocytes from gastric cancer patients, suggesting that F4.2 peptide could be used as a cancer vaccine for gastric tumors. The natural antigenic peptide of OSC-20 was also determined using acid extraction and biochemical separation and by mass spectrometry. Consequently, OSC-20 peptide was designated as the 6-1-5 peptide, an HLA-DRB1*08032-restricted 16-mer peptide with two possible anchor motifs. It has an amino acid sequence identical to that of human alpha-enolase, suggesting that it was derived from the processed parental alpha-enolase protein. We are presently attempting to determine the genes that code tumor rejection antigens recognized by HLA-A24- and A26-restricted T cells, including those of pulmonary and pancreatic carcinomas. The search for these antigenic peptides may lead to the identification of immunogenic peptide antigens that would be suitable for clinical use in commonly occurring epithelial cancers.

Effects of brain-derived neurotrophic factor and neurotrophin-4 on isolated cultured retinal ganglion cells: evaluation by flow cytometry

PURPOSE

Effects of brain-derived neurotrophic factor (BDNF) and neurotrophin (NT)-4 on retinal ganglion cells (RGCs) isolated and cultured in a serum-free medium are evaluated objectively by using flow cytometry.

METHODS

RGCs from the retinas of 2-day-old rats were isolated in a two-step panning and cultured in a serum-free medium. BDNF (1, 10, and 100 pg/ml or 1, 10, and 100 ng/ml), NT-4 (0.1, 1, 10, and 100 ng/ml) or their vehicle, phosphate-buffered saline, were individually added to aliquots of the medium to be cultured for 48 hours. Then, after adding 5-chloromethylfluorescein diacetate, the survival of RGCs was evaluated using flow cytometry.

RESULTS

The method used allowed the authors to analyze 10,000 RGCs per sample in approximately 2 minutes, so that a much larger number of cells was evaluated in a shorter period than with previously reported methods. RGCs were classified into either large or small RGCs, and the survival of each of these groups was determined objectively by the amount of fluorescent emission. BDNF improved the survival rate of RGCs concentration-dependently. In particular, the survival rate of small RGCs was greatly improved. BDNF at 100 ng/ml increased the survival rate of small RGCs by 17.4% and that of large RGCs by 7.8% in comparison to the controls. NT4 did not significantly improve the survival rates of either large or small RGCs.

CONCLUSIONS

BDNF improved the survival rate of RGCs, particularly of small RGCs, concentration-dependently, but NT-4 had little influence on the survival rate. The current method was useful in evaluating the effects of neuroprotective factors or neurotoxic factors on cultured RGCs.

Measurement of adenylate cyclase activity in the minute bovine ciliary epithelial cells during the pharmacological stimulation of adrenergic and cholinergic receptors

Although essential to the secretion of aqueous humor, little is known about the signal transduction underlying postreceptor adrenergic and cholinergic processes in the ciliary epithelium. We adopted a highly sensitive fluorometric assay technique in order to examine adenylate cyclase activity in minute membrane preparations made from the bovine ciliary epithelial cells. The protein concentration of the preparation was 3-5 mg/ ml. Norepinephrine (10(-7), 10(-6) and 10(-5) M) and carbachol (10(-7) and 10(-5) M) were incubated with 10 microl of membrane preparation to analyze the extent of the receptor-coupled influences on the adenylate cyclase activity. Meanwhile, forskolin (10(-5) M) was used to estimate the maximum adenylate cyclase activity. After the initial enzymatic destruction of noncyclic adenine nucleotides and phosphorylated metabolites, the diester linkage of cyclic AMP was cleaved and then converted to ATP. The ATP was enzymatically amplified to about 10,000 times of fructose-6-phosphate. The NADPH, formed when the fructose-6-phosphate was converted to 6-phosphogluconolactone, was measured fluorometrically. Basal and forskolin-stimulated maximum adenylate cyclase activities (pmol/mg protein/min) were 29.6+/-7.6 and 86.6+/-7.2 (mean+/-SE), respectively. Norepinephrine increased the adenylate cyclase activity in a dose-dependent manner, while carbachol hardly affected the activity. These results indicate that the adenylate cyclase activity can be measured in the minute ciliary epithelial cells and, moreover, that the current assay can be applied to assess the efficacy of newly available ophthalmic solutions or systemic drugs influencing adenylate cyclase activity in a discrete portion in the eye.

Clinical usefulness of microsatellite instability for the prediction of gastric adenoma or adenocarcinoma in patients with chronic gastritis

To assess a role of microsatellite instability (MSI) in the development of gastric adenocarcinoma or adenoma from chronic gastritis, we analysed mutations of five microsatellite loci in gastritis, adenoma and adenocarcinoma retrospectively. Gastric mucosa was biopsied from the same area in each patient at different periods and examined for MSI. Only one of 55 patients with chronic gastritis revealed MSI-H phenotype and the other 54 patients showed microsatellite stable (MSS) phenotypes. In six of 17 patients with gastric adenoma or well-differentiated adenocarcinoma, MSI-positive phenotypes were demonstrated. Interestingly, all of six patients showing MSI, including three high-level MSI (MSI-H) cases and three low-level (MSH-L) cases, had already revealed MSI at the stage of chronic gastritis. In two of three MSI-H cases, the identical MSI patterns had been observed at the stage of gastritis 1.5-7 years before the final diagnosis of adenocarcinoma. The adjacent gastritis mucosa within 10 mm from the carcinoma demonstrated MSI as well. MSI was not found in any of 35 patients with Helicobacter pylori infection, but found in one of 30 patients without infection. Moreover, two of three cases of gastric adenoma or well-differentiated adenocarcinoma with MSI-H at the stage of chronic gastritis showed no evidence of Helicobacter pylori infection throughout the observation periods. These results indicate that MSI in biopsy specimens at the stage of chronic gastritis may predict the risk of the progression to adenoma and well-differentiated adenocarcinoma, and that Helicobacter pylori infection itself may not induce MSI directly in the gastric mucosa.

Circadian rhythm of autonomic nervous function in patients with normal-tension glaucoma compared with normal subjects using ambulatory electrocardiography

PURPOSE

To compare circadian rhythm of autonomic nervous function in patients with normal-tension glaucoma with subjects with normal eyes.

METHODS

Thirty-two patients with normal-tension glaucoma and 32 age-matched normal subjects who had no history of systemic disorders and no currently treated systemic disorders, especially diseases of the autonomic nervous system, were studied. An ambulatory electrocardiogram was installed that recorded heartbeats for 48 hours. Low-frequency and high-frequency values were calculated as markers of the autonomic nervous system status based on heart-rate variability using a power-spectrum analysis.

RESULTS

The low-frequency values of patients with normal-tension glaucoma during the spans of an active day and a resting night were significantly greater than those of normal subjects, and this difference was emphasized during the night resting span. However, the high-frequency values of patients with normal-tension glaucoma were similar to those of normal subjects. The normal subjects showed a significant age-related decrease in all investigated parameters except the low-frequency values during the resting span. However, the patients with normal-tension glaucoma showed a significant age-related decrease only in low-frequency values during the active day. Patients with normal-tension glaucoma with progressive visual field defects showed much greater values than other cases, although the values were not significantly different.

CONCLUSION

These results indicate that a disturbance of the circadian rhythm of the autonomic nervous system may exist in patients with normal-tension glaucoma.

Polyamines: mysterious modulators of cellular functions

In recent years the functions of polyamines (putrescine, spermidine, and spermine) have been studied at the molecular level. Polyamines can modulate the functions of RNA, DNA, nucleotide triphosphates, proteins, and other acidic substances. A major part of the cellular functions of polyamines can be explained through a structural change of RNA which occurs at physiological concentrations of Mg(2+) and K(+) because most polyamines exist in a polyamine-RNA complex within cells. Polyamines were found to modulate protein synthesis at several different levels including stimulation of special kinds of protein synthesis, stimulation of the assembly of 30 S ribosomal subunits and stimulation of Ile-tRNA formation. Effects of polyamines on ion channels have also been reported and are gradually being clarified at the molecular level.