Cataract in atomic bomb survivors.

PURPOSE: Ophthalmologic examinations were conducted on atomic bomb (A-bomb) survivors 55 years after exposure. MATERIALS AND METHODS: A-bomb survivors who had been exposed before 13 years of age at the time of the bombings in 1945 or who had been examined in a previous study between 1978 and 1980. The examinations, conducted between June 2000 and September 2002, included slit-lamp examination, digital photography and a cataract grading system for three parts of the lens (nucleus, cortex and posterior subcapsule) as an outcome variable. Proportional odds logistic regression analysis was conducted using the lowest grading class as a reference and included explanatory variables such as age, sex, city, dose and various cataract-related risk factors. When the grades in an individual differed, the worst grade was used. RESULTS: Results indicate that odds ratios (ORs) at 1 Sv were 1.07 (95% confidence intervals [CI] 0.90, 1.27) in nuclear colour, 1.12 (95% CI 0.94, 1.30) in nuclear cataract, 1.29 (95% CI 1.12, 1.49) in cortical cataract and 1.41 (95% CI 1.21, 1.64) in posterior subcapsular cataract. The same was true after excluding 13 people whose posterior subcapsular cataracts had been previously detected. CONCLUSION: Significant radiation effects were observed in two types of cataracts in A-bomb survivors.

Microscale synthesis of dextran-based multivalent N-linked oligosaccharide probes.

We developed a convenient method for the synthesis of dextran-based multivalent probes containing N-linked oligosaccharides which is efficient even in a small scale. Oligosaccharides were derivatized with succinic dihydrazide and dimethylamine borane under a mild acidic condition. The derivatized oligosaccharides were then conjugated in a good yield to periodate-oxidized dextran (500 kDa). Thus, the conjugates containing 120 to 140 oligosaccharide chains per dextran molecule were successfully synthesized. Their practical advantage was shown by the example that the asialofetuin oligosaccharide-dextran conjugate has much higher affinity to Ricinus communis agglutinin (RCA-I) than asialofetuin oligosaccharide itself or asialofetuin. The conjugates were further labeled with fluorescent reagent or biotinylation reagent containing a hydrazino group by the use of the unreacted aldehyde groups of the oxidized dextran, yielding probes with similar densities of fluorophores or biotin groups. Direct binding of the biotinylated asialofetuin oligosaccharide-dextran probe to RCA-I coated on the titer plate at a concentration of 50 ng/50 microl was easily detected using 50 fmol (as oligosaccharides) of the probe. The method for the synthesis of dextran-based oligosaccharide probes will facilitate the investigation of carbohydrate-mediated molecular interactions based on the native oligosaccharide structures.

A study on the irregularity of the sequence of R-R intervals in chronic atrial fibrillation in man based on the time series analysis and the information theory.

The mechanism of the irregularity of R-R intervals and especially the genesis of the long R-R intervals in atrial fibrillation were clarified. From the point of view of the present study, the sequence of successive R-R intervals can be regarded as a stochastic process, and consequently mathematical analyses can be applied, and the following conclusion could be obtained: the stability of the data, mathematically called stationarity, is present in the sequence of R-R intervals, and these intervals are independently and identically distributed. The probability density function is an Erlangian distribution with phase k of 20 to 26. Namely, as soon as, on the average, 20 to 26 atrial excitatory stimuli have arrived at the AV node, a threshold value of the AV node is reached and ventricular activation is induced. However, if we examine the mathematical structure of the sequence of successive R-R intervals in more detail, the following results can be evidently obtained: during atrial fibrillation with rapid ventricular response, the sequence of R-R intervals is completely independent, but with intermediate or slow ventricular response the adjacent R-R intervals correclate with each other and these adjacent intervals have at least the first order Markov property, which seems to be caused by the concealed conduction. Because of this Markow property due to the prolongation of the refractory period of the AV node, slow ventricular response results.

Detection of carbohydrate recognition molecules on the plasma membrane of boar sperm by dextran-based multivalent oligosaccharide probes.

Two kinds of molecules, one recognizing the sialo-/asialo-N-acetyllactosamine structures and the other recognizing the Lewis X structure in a divalent cation-independent manner, were detected on the head of boar sperm prepared from cauda epididymis by fluorescence-labeled or biotinylated dextran-based multivalent oligosaccharide probes. The N-acetyllactosamine recognition molecule(s) is weakly detected on uncapacitated sperm and becomes strongly detectable on capacitated sperm. On the other hand, the Lewis X recognition molecule is detected at a moderate level before capacitation and at a high level after capacitation. Both molecules disappear from the sperm head after induction of acrosome reaction and also by mild detergent treatment. Thus, the two kinds of carbohydrate molecules are expressed on the plasma membrane of boar sperm depending on their physiological state. Inhibition study of the oligosaccharide-dextran probe binding to isolated sperm plasma membrane by various glycoproteins, oligosaccharides, and sulfated polysaccharides also supported the occurrence of the two distinct kinds of molecules.

Calcium ion-independent recognition of sialyl and nonsialyl N-acetyllactosamine and Le(x) structures by boar sperm.

Recognition of defined carbohydrate structures by boar sperm was studied on the basis of oligosaccharide structures of porcine zona pellucida glycoproteins so far elucidated. Boar sperm abundantly adhered to fetuin-Sepharose beads, moderately to asialofetuin-Sepharose beads, but not at all to galactosidase (beta1-4-linkage-specific)-digested asialofetuin-Sepharose beads. The sperm also adhered to Le(x) oligosaccharide probe-coupled avidin-Sepharose beads. These adhesive activities were retained in the medium containing EDTA instead of calcium ion but abolished after induction of acrosome reaction by preincubation of sperm with calcium ionophore. Inhibition study of sperm adhesion to the beads by soluble ligands demonstrated that boar sperm express at least two kinds of carbohydrate recognition molecules, one recognizing both sialyl and nonsialyl N-acetyllactosamines but not the Le(x) structure and the other recognizing the Le(x) structure but not N-acetyllactosamines. Sperm binding to the zona pellucida on fixed porcine oocytes was inhibited by N-glycans of fetuin and their asialo form but not by the asialo, agalacto-N-glycans. Finally, dextran-based multivalent oligosaccharide polymers were prepared and their inhibitory activities in sperm-oocyte binding were examined. The result indicated that the polymer composed of fetuin N-glycans, its asialo-N-glycans, or lacto-N-fucopentaose III causes a remarkable inhibition at the oligosaccharide-based concentration of 50 microM. Thus, boar sperm are suggested to express multiple carbohydrate recognition molecules which may be involved in the sperm-egg interaction.