Reexamination of Dopaminergic Amacrine Cells in the Rabbit Retina: Confocal Analysis with Double- and Triple-labeling Immunohistochemistry

Dopaminergic amacrine cells (DACs) are among the most well-characterized neurons in the mammalian retina, and their connections to AII amacrine cells have been described in detail. However, the stratification of DAC dendrites differs based on their location in the inner plexiform layer (IPL), raising the question of whether all AII lobules are modulated by dopamine release from DACs. The present study aimed to clarify the relationship between DACs and AII amacrine cells, and to further elucidate the role of dopamine at synapses with AII amacrine cell. In the rabbit retina, DAC dendrites were observed in strata 1, 3, and 5 of the IPL. In stratum 1, most DAC dendritic varicosities—the presumed sites of neurotransmitter release—made contact with the somata and lobular appendages of AII amacrine cells. However, most lobular appendages of AII amacrine cells localized within stratum 2 of the IPL exhibited little contact with DAC varicosities. In addition, double- or triple-labeling experiments revealed that DACs did not express the GABAergic neuronal markers anti-GABA, vesicular GABA transporter, or glutamic acid decarboxylase. These findings suggest that the lobular appendages of AII amacrine cells are involved in at least two different circuits. We speculate that the circuit associated with stratum 1 of the IPL is modulated by DACs, while that associated with stratum 2 is modulated by unknown amacrine cells expressing a different neuroactive substance. Our findings further indicate that DACs in the rabbit retina do not use GABA as a neurotransmitter, in contrast to those in other mammals.

Vitamin B Status and Serum Homocysteine Levels in Infertile Women

Adequate vitamin B(2), vitamin B(6), folate and vitamin B(12) nutrition is known to be important for reproductive function in women of childbearing age. The purpose of this study was to evaluate serum vitamin B(2), vitamin B(6), folate and vitamin B(12) status and serum homocysteine levels in 115 women aged 33.2 +/- 4.0 years, who had been diagnosed with infertility, and 49 women aged 34.5 +/- 3.8 years having at least one born child. Total vitamin B(2) and vitamin B(6) intakes in infertile women were significantly lower than those in control. Serum vitamin B(2), vitamin B(6), folate and vitamin B(12) concentrations were significantly lower in infertile women than those in control and serum homocysteine levels were significantly higher in infertile women than those in control. Thirteen percent in infertile women and zero percent in control were assessed as hyperhomocysteinemic and there was a significant difference in the prevalence of hyperhomocysteinemia between infertile women and control. 41% infertile women were assessed as folate deficiency. Serum folate concentrations was negatively correlated with serum homocysteine of the infertile women and control. Total vitamin B2 intakes was negatively correlated with serum homocysteine of the infertile women and control. Total vitamin B6, folate intakes were negatively correlated with homocysteine of infertile women only. In conclusion, infertile women are needed to intake more B vitamins intakes. Furthermore researches are needed to estimate adequate B vitamin supplementation in infertile women.

Decentration and Tilt of Posterior Chamber Lens According to Anterior Capsulotomy

To evaluate the abnormal positions of intraocular lens after cataract extraction and intraocular lens implantation, the study used the image analysis technique. Tilting and decent ration of posterior chamber intraocular lens(PCL) were studied according to the anterior capsulotomy. 103 patients(120 eyes) were randomized into 6 groups(20 eyes each) according to posterior chamber lens style and anterior capsulotomy type, and measured the degrees of tilting and decent ration of PCL by Scheimpflug camera. Three piece PCL implantation group showed significant less tilting than one piece PCL implantation group at postoperative 1 week. In one radial tear of anterior capsulotomy group, three piece PCL showed less tilting than one piece PCL. At postoperative 2 months, continuous curvilinear capsulorhexis without radial tear group showed significant less decent ration and tilting than one radial tear group. At postoperative 1 week and 2 months tilting of the continuous curvilinear capsulorhexis group was less than two or more radial tears group. As time passes from 1 week to 2 months tilting decreased significantly, but decentration did not showed significant decrease.

Prevention of Adhesion Syndrome after Extraocular Muscle Surgery in Rabbit

Several high molecular weight polymers were tested as a barrier against adhesion between extraocular muscle and its surrounding tissue in a rabbit. We used 48 rabbits to investigate the efficacy of hyaluronic acid, methylcellulose, and gel form as compared to balanced salt solution as a control group in reducing the postoperative adhesion. Under general anesthesia, superior rectus muscle was detached and reattached to original insertion site after coating with barrier materials. Rabbits were killed and histologic examinations were done for degree of adhesion formation at 1. 2, 3, and 6 weeks after surgery. The results were as follows; 1. In control group, the portion that showed the most severe fibrosis was within muscle itself and the portion of the least fibrosis was between muscle and sclera. But in experimental group, there was no differences in degree of fibrosis according to operation site. 2. In control group, the fibrosis progressively increased during the postoperative 6 weeks. In hyaluronic acid group and methylcellulose group, the fibrosis decreased from postoperative 1 week and the degree of decreased fibrosis was more evident in methylcellulose group. In gelform group, fibrosis decreased until postoperative 3 weeks and then increased at postoperative 6 weeks. And one case of foreign body reaction was noted in gel form group. The above results suggest that high molecular weight polymers such as hyaluronic acid and methylcellulose are effective in prevention of adhesion syndrome after extraocular muscle surgery and that methylcellulose is more effective compared to hyaluronic acid.