bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dual Effect of Melatonin on Gonadotropin-Releasing-Hormone-Induced Ca<sup>2+</sup> Signaling in Neonatal Rat Gonadotropes
Authors: Zemkova Hana , Vanecek Jiri 
Published: April 2003

In neonatal rat gonadotropes, melatonin inhibits gonadotropin-releasing-hormone (GnRH)-stimulated increase in intracellular Ca<sup>2+</sup> concentration ([Ca<sup>2+</sup>]<sub>i</sub>); in cells transfected with the Mel1a melatonin receptor, however, melatonin has been shown to potentiate agonist-stimulated [Ca<sup>2+</sup>]<sub>i</sub> increase. To elucidate this discrepancy, we investigated the effects of melatonin in neonatal gonadotropes over a wide range of melatonin concentrations. Nystatin perforated patch recording of Ca<sup>2+</sup>-dependent potassium currents was used to monitor GnRH-induced [Ca<sup>2+</sup>]<sub>i</sub> changes. In 32% of cells, increasing melatonin concentrations in the range of 1 p<i>M</i> to 100 n<i>M</i> prolonged the latency of, and inhibited GnRH (10 n<i>M</i>)-stimulated [Ca<sup>2+</sup>]<sub>i</sub> increases in a concentration-dependent manner. In the remaining 68% of cells, the Ca<sup>2+</sup> increase elicited by exposure to 10 n<i>M</i> GnRH was also inhibited by picomolar concentrations of melatonin, but at nanomolar concentrations the inhibitory effect disappeared and melatonin was only able to prolong the latency of the response. This dual effect of melatonin however was not observed in cells stimulated with lower (2 n<i>M</i>) GnRH concentrations; in that case, melatonin was inhibitory at all concentrations tested with an IC<sub>50</sub> of about 30 p<i>M</i>. In contrast, application of nanomolar concentrations of melatonin resulted in potentiation of the GnRH-induced Ca<sup>2+</sup> increase in a small population of gonadotropes which did not respond by inhibition or prolonged latency. These results indicate that in neonatal gonadotropes, melatonin has both inhibitory and potentiating effects on GnRH-stimulated [Ca<sup>2+</sup>]<sub>i</sub> increases. Ranges of concentrations needed to produce either effect suggest that two distinct G proteins may be involved, as already observed in transfected cells.
Exogenous Nitric Oxide Inhibits VCAM-1 Expression in Human Peritoneal Mesothelial Cells
Authors: Lee Sang Koo , Kim Ji Hoon , Yang Won Seok , Kim Soon Bae , Park Su-Kil , Park Jung Sik 
Published: April 2003

Leukocyte adhesion to mesothelium is an important step during peritonitis, which is mediated by adhesion molecules including vascular cell adhesion molecule-1 (VCAM-1). We investigated the effect of exogenous nitric oxide (NO) on VCAM-1 expression in cultured human peritoneal mesothelial cells and its signal transduction pathway. Mesothelial cells were exposed to tumor necrosis factor-α (TNF-α) in the presence or absence of NO donors, 3-morpholino-sydnonimine (SIN-1) and nitroprusside (NP). VCAM-1 mRNA and protein expression were measured by Northern blot analysis and flow cytometry. Nuclear factor-ĸB (NF-ĸB) binding activity was determined by electrophoretic mobility shift assay. Both SIN-1 and NP inhibited the TNF-α induced VCAM-1 mRNA expression in a dose dependent manner (0.25–2 m<i>M</i>). SIN-1 also suppressed the cell surface expression of VCAM-1 molecule. Furthermore, SIN-1 and NP inhibited the VCAM-1 mRNA expression induced by interleukin-1β or lipopolysaccharide as well. NF-ĸB inhibitor, PDTC dose dependently inhibited the TNF-α induced VCAM-1 mRNA expression. SIN-1 inhibited the TNF-α- induced NF-ĸB binding activity. Analogue of cGMP (8-bromo-cGMP) had no significant effect on TNF-α-induced VCAM-1 mRNA expression and guanylate cyclase inhibitor (ODQ) also had no significant influence on the inhibitory effect of SIN-1. These results suggest that exogenous NO inhibits VCAM-1 expression via suppression of NF-ĸB through a cGMP-independent pathway.
Multiple Sclerosis and Dental Amalgam: Case-Control Study in Ferrara, Italy
Authors: Casetta Ilaria , Invernizzi Matteo , Granieri Enrico 
Published: April 2003

Dental amalgam fillings containing mercury have been suggested as a possible risk factor for multiple sclerosis (MS). In the context of a wider program of investigation into environmental risk factors and MS, we conducted a case-control comparison to investigate the alleged association between MS, dental caries, and amalgam fillings. We included 132 MS patients with onset during the last 16 years and 423 controls, matched to cases for sex, age and residence. Data were collected by a personal interview conducted by trained doctors. Cases and controls gave informed consent. Although we report a trend toward a higher number of dental fillings in cases than controls, odds ratios for subjects with exposures of different duration and with different numbers of amalgam fillings were not statistically significant. This case-control study failed to demonstrate an association between either the number of dental amalgam fillings or the duration of exposure to mercury amalgam and MS.
Alpha-2-Adrenoreceptors in Depressed Suicide Attempters: Relationship with Medical Lethality of the Attempt
Authors: Pitchot William , Hansenne Michel , Pinto Emmanuel , Reggers Jean , Fuchs Sonia , Ansseau Marc 
Published: April 2003

Several lines of evidence tend to suggest a role for noradrenaline, and more specifically alpha-2-adrenoreceptors, in the biology of suicidal behavior. The purpose of this study was to assess the growth hormone (GH) response to clonidine, an alpha-2-adrenergic agonist, in majorly depressed inpatients with a history of highly lethal suicide attempt compared to depressed patients with a history of low lethal suicide attempt and nonattempters. Our sample included 20 male depressed inpatients with a history of suicide attempt compared to 20 male depressed nonattempters. We did not observe any significant difference between suicide attempters and nonattempters for GH peak values (2.4 ± 2.9 vs. 4.1 ± 3.7 ng/ml; F = 2.52, d.f. = 1, 38, p = 0.12). Moreover, GH peak responses to clonidine were not related to the degree of lethality of the attempt. The results of the present study do not support a major role for noradrenaline in the biology of suicidal behavior.
Application of Classification Tree and Neural Network Algorithms to the Identification of Serological Liver Marker Profiles for the Diagnosis of Hepatocellular Carcinoma
Authors: Poon Terence Chuen-Wai , Chan Anthony Tak-Cheung , Zee Benny , Ho Stephen King-Wah , Mok Tony Shu-Kam , Leung Thomas Wai-Tong , Johnson Philip James 
Published: April 2003

<i>Objective:</i> Although many attempts have been made to identify tumour-specific α-fetoprotein (AFP) glycoforms or other serological markers for the diagnosis of hepatocellular carcinoma (HCC), none of the available markers has, so far, shown satisfactory sensitivity and specificity. Here we aimed to apply classification tree and neural network algorithms to interpret the levels of multiple serological liver markers to improve overall specificity and sensitivity, particularly with a view to discriminating between liver cirrhosis with and without HCC. <i>Methods:</i> We developed classification trees and neural networks that identified serological liver marker profiles comprising AFP, α1-antitrypsin (A1AT), α2-macroglobulin (A2MG), thyroxine-binding globulin (TBG), transferrin and albumin as well as sex and age, which might permit the diagnosis of HCC. Data were collected from 65 HCC patients, 51 patients with liver cirrhosis alone (LC) and 51 normal healthy subjects. <i>Results:</i> The generated classification trees and neural networks showed similar diagnostic values in differentiating HCC from LC. The classification trees identified AFP, A1AT and albumin as the most important classification parameters, whereas the neural networks identified A2MG, AFP, A1AT and albumin as the predominant factors. The classification logic of the classification trees indicated that more HCC cases could be identified among cases with slightly elevated AFP levels by using the serum levels of A1AT and albumin. The neural networks were also useful for the identification of the HCC cases when the AFP levels were below 500 ng/ml (p < 0.005). The neural networks could identify HCC cases with AFP levels within the normal range, but the classification trees could not. By combining the conventional AFP test and the neural networks, the overall diagnostic sensitivity for HCC was significantly increased from 60.0 to 73.8% (p < 0.05) while maintaining a high specificity (88.2%). The sensitivities for tumors of different sizes were similar. <i>Conclusion:</i> The neural network algorithm appeared to be more powerful than the classification tree algorithm in the identification of the distinctive serological liver marker profiles for the diagnosis of the HCC subgroup without significant elevation in serum AFP levels. By incorporating serological levels of other liver markers and including data from a large number of patients and control subjects, it should prove possible to develop a versatile neural network for early diagnosis of HCC.
Automatic Static Threshold Perimetry Is Useful for Estimating the Effects of Laser Photocoagulation on Diabetic Maculopathy
Authors: Okuyama Michiko , Okisaka Shigekuni 
Published: April 2003

Focal photocoagulation was performed on 18 eyes in 18 diabetes patients; a visual acuity test, fluorescein angiography and automated static threshold perimetry by Octopus automated static perimetry (program 31) were conducted before and 1, 3 and 6 months after krypton laser photocoagulation. Central field sensitivity and total loss were measured by automated static threshold perimetry. Group A (13 eyes) had a total loss of less than 150 dB. In these subjects, mild fluorescein leakage was detected within the area of the vascular arcade. In group B (5 eyes) with a total loss of greater than 150 dB, diffuse fluorescein leakage was also detected outside the vascular arcade. The central field sensitivity was reduced in 2 eyes of group B. The total loss worsened in 8 eyes of group A (61.5%) and 5 eyes of group B (100%). Inspection of photographs gave the impression that the degree of fluorescein leakage and the area of the avascular zone on fluorescein angiography accorded with total loss, thus suggesting that total loss reflects visual functions better than visual acuity or central field sensitivity. Therefore, automated static threshold perimetry appears to be a useful method for estimating visual functions after photocoagulation in diabetic maculopathy patients.
Visual Function and Gene Analysis in a Family with Oguchi’s Disease
Authors: Yoshii Masaru , Murakami Akira , Akeo Kiyoshi , Nakamura Atsuo , Shimoyama Masaru , Ikeda Yoko , Kikuchi Yasuhiro , Okisaka Shigekuni , Yanashima Kenji , Oguchi Yoshihisa 
Published: April 2003

A family with 1 case of retinitis pigmentosa (III-1) and 2 cases of Oguchi’s disease (III-2, 3) was examined in terms of electrophysiology as well as molecular biology. The proband (III-3), a 42-year-old female, and 2 older brothers (III-1, 2, aged 52 and 45 years) and 2 unaffected members in the same family participated in this study. Corrected visual acuities of the individuals with Oguchi’s disease (III-2, 3) were 1.2. On funduscopy, blood vessels stood out in relief against a metallic-appearing background and a Mizuo-Nakamura phenomenon was evident. Full-field electroretinograms (ERGs) recorded from the proband were indicative of rod dystrophy, but results of other electrophysiological examinations (multifocal ERG, pattern ERG and visual-evoked cortical potential recordings) were within normal limits. Patient III-1 had corrected visual acuities of RE 20 cm/m.m. and LE 30 cm/n.d., severe chorioretinal atrophy in both fundi, and full-field ERG revealed rod-cone dystrophy. Mutation of the arrestin gene (1147de1A) was detected in all 3 cases, but no mutation was observed for the rhodopsin gene. A homozygous deletion 1147 (1147de1A) in codon 309 of the arrestin gene was commonly observed in all 3 patients. Visual function in each patient coincides with that of retinitis pigmentosa or Oguchi’s disease, respectively.
The Effects of High-Dose Corticosteroid Therapy on Optic Nerve Head Blood Flow in Experimental Traumatic Optic Neuropathy
Authors: Lew Helen , Lee Sang Yeul , Jang Jae Woo , Kim Hye Young , Kang Shin Jeong , Kim Sung Joo 
Published: April 2003

<i>Purpose:</i> The objective of this study was to ascertain the effect of high-dose steroid therapy in traumatic optic neuropathy using the Heidelberg retina flowmeter (HRF) to detect changes in optic nerve head blood flow. <i>Methods:</i> We experimentally damaged the optic nerves of 10 white rabbits with a Hartman mosquito clamp. The first group (n = 5) was treated with intravenous dexamethasone (0.25 mg/kg) every 6 h for a 48-hour period. The second group (n = 5) served as controls. Both groups were tested prior to operation, 1 week, 1 month and 2 months after surgery. <i>Results:</i> Experimental optic nerve damage caused a significant decrease in optic nerve head blood flow of 50.51% (p = 0.001), with a volume decrease of 46.02% (p = 0.001) and a velocity reduction of 43.12% (p = 0.002) compared to the baseline. After 2 months, in the group treated with high-dose corticosteroid therapy, optic nerve head blood flow was increased by 76.90% (p = 0.012), volume by 77.53% (p = 0.012) and velocity by 47.21% (p = 0.012) compared to the control group. <i>Conclusion:</i> The high-dose corticosteroid therapy improved the optic nerve head blood flow as demonstrated in experimental traumatic optic neuropathy. The HRF may be used to assess the therapeutic responses in traumatic optic neuropathy under variable conditions.
Developmental Expression of GABA<sub>A</sub> Receptors in Retinal Transplants
Authors: Sharma Rajesh Kumar 
Published: April 2003

γ-Aminobutyric acid (GABA) has transiently been found in certain retinal cells during development, and thus it has been suggested that besides its role as an inhibitory neurotransmitter, it also plays a role during the development of the retina. Further it has been suggested that this developmental role of GABA is mediated through GABA<sub>A</sub> receptors. Retinal cell transplants are being tried for the treatment of degenerative retinal disorders. Even though the donor tissue continues to proliferate, to develop and to differentiate after transplantation, its development is not entirely normal. Various neurotransmitters have been found in retinal transplants, but the receptors, which are needed for their action, have not been demonstrated. It was therefore of interest to see the expression of GABA<sub>A</sub> receptors during the development of the transplants. Embryonic day (E) 15 rabbit retinas were transplanted into the eyes of adult rabbits. Transplants were allowed to survive for various times so that the grafts attained the equivalent ages of (donor age + survival time) E 19, 21, 26, 29 and postnatal (PN) day 2, 5, 9, 19 and 95. On formaldehyde-fixed cryostat sections of the transplant tissue immunohistochemistry was performed. Antibodies against the α<sub>1</sub> and β<sub>2/3</sub> subunits of the GABA<sub>A</sub> receptors were used to demonstrate these receptors. No immunoreactivity was detected in transplants of ages E 19 and 22. The GABA<sub>A</sub> receptor β<sub>2/3</sub> subunit first appeared in E 29 transplants, whereas the GABA<sub>A</sub> receptor α<sub>1</sub> subunit was first detected at PN 2. At these ages faint immunoreactivity was detected in certain plexiform layers in the transplants. In older ages the immunoreactivity increased and also appeared in certain cells lying in between the rosettes along with the plexiform layers that are equivalent to the inner and the outer plexiform layers of the normal retina. The development of the GABA<sub>A</sub> receptor α<sub>1</sub> and β<sub>2/3</sub> subunit immunoreactivity compared well with that during the development of the normal retina. The results suggest that GABA present in the retinal transplants can exert its action through its receptors.
Intravitreal Trovafloxacin against Experimental <i>Staphylococcus epidermidis</i> Endophthalmitis
Authors: Karaküçük Sarper , Mirza Ertuǧrul , Sümerkan Bülent , Okten Turhan 
Published: April 2003

This study was designed to test the effects of intravitreal trovafloxacin on an experimental rabbit model of <i>Staphylococcus epidermidis</i> endophthalmitis. Out of 26 rabbits, 22 were given intravitreal <i>S. epidermidis</i> (100,000 CFU). At 24 h, group 1 (8 rabbits) and, at 48 h, group 2 (8 rabbits) received 100 µg intravitreal trovafloxacin. Group 3 (6 rabbits) was used as inoculated but untreated controls. Four rabbits (group 4) were used as uninfected controls. Clinical scores were calculated at 24, 48 and 72 h. Microbiological and histopathological scorings were made. Microbiological analysis showed that trovafloxacin administered at 24 or 48 h significantly reduced the number of bacteria compared to the untreated group. We conclude that trovafloxacin applied at 24 or 48 h is effective against <i>S. epidermidis</i> endophthalmitis in this experimental rabbit model.
Effects of Topical Clonidine on Prostaglandin-E<sub>2</sub>-Induced Aqueous Flare Elevation in Pigmented Rabbits
Authors: Watanabe Kazuhiko , Hayasaka Seiji , Hiraki Shigeyoshi , Matsumoto Masayuki , Kadoi Chiharu , Nagaki Yasunori , Hayasaka Yoriko 
Published: April 2003

We evaluated the role of topical clonidine on experimental ocular inflammation. Transcorneal diffusion of prostaglandin (PG) E<sub>2</sub>, 7.09 × 10<sup>–2</sup> mmol/l, with the use of a glass cylinder was employed to produce aqueous flare elevation in pigmented rabbits. Clonidine was topically administered and yohimbine was injected intravenously. Aqueous flare was measured with a laser flare cell meter. Topical instillation of 0.25% clonidine inhibited 89% of PGE<sub>2</sub>-induced aqueous flare elevation. Instillation of clonidine at 60 or 30 min before and 10 min after PGE<sub>2</sub> inhibited flare significantly. Pretreatment with intravenous yohimbine decreased the clonidine-induced inhibition of the flare elevation in a dose-dependent manner. It is possible that the anti-inflammatory action of topical clonidine may be mediated partly by α<sub>2</sub>-receptors.
Distribution and Isoform Characterization of Type XII Collagen in Bovine Cornea
Authors: Kato T. , Nakayasu K. , Kanai A. , Nishiyama T. , Imamura Y. , Hayashi T. 
Published: April 2003

Streptavidin peroxidase immunohistochemistry and immunoelectron microscopy were used to determine the localization of type XII collagen in sections from bovine corneas. Type XII collagen extracted from bovine cornea and skin was assayed by Western blotting. Immunohistochemical experiments showed that type XII collagen was restricted to the corneal stroma; it was not present in corneal epithelium, epithelial basement membrane, Descemet’s membrane or endothelium. Type XII collagen was distributed throughout the corneal stroma, and it was prominently localized at the superficial stroma. Immunoelectron-microscopic examination demonstrated that type XII collagen was regularly found along the surface of banded collagen fibrils with a periodic distribution. By Western blot analysis, we observed that extracts from bovine cornea contained both the long and short isoforms of type XII collagen, whereas extracts from bovine skin contained only the short isoform. The homogeneous distribution and/or presence of the long isoform of type XII collagen may be related to the characteristically regular arrangement of collagen fibrils and thereby the transparency of corneal tissue.
Facilitatory and Neurotoxic Effects of Intravitreal Ornithine on the Electroretinographic Responses of Albino Rats
Authors: Mizota Atsushi , Sato Eiju , Adachi-Usami Emiko 
Published: April 2003

The effect of an intravitreal injection of ornithine on the retina of rats was studied electroretinographically. Rats were injected intravitreally with 5 µl of 0.02, 0.25 and 0.5 <i>M</i> ornithine. Electroretinograms (ERGs) were recorded before, and 1, 3 and 9 days after the injection. High doses of ornithine (0.5 <i>M</i>) reduced while low doses (0.02 <i>M</i>) enhanced the ERG amplitudes. The implicit time of the a-wave was delayed at all concentrations after ornithine injection, which suggests that implicit times may be a more sensitive parameter of the ornithine effect. There were significant changes in the stimulus intensity necessary to obtain the one half of the maximum amplitude of the b-wave that may have been caused by damage of the photoreceptors and retinal pigment epithelium cells by ornithine. We conclude that the effect of ornithine on retinal function is dose dependent and can either enhance or depress the ERG amplitudes.
Turnover and Migration of Meibomian Gland Cells in Rats’ Eyelids
Authors: Olami Yael , Zajicek Gershom , Cogan Michael , Gnessin Hadassah , Pe’er Jacob 
Published: April 2003

<i>Purpose: </i>The object of this study is to determine the velocity and migration course of meibomian gland cells. <i>Materials and Methods: </i>Twenty-seven adult rats weighing about 200 g were injected intraperitoneally with a single dose of 0.5 µCi [<sup>3</sup>H]-thymidine/g body weight. Three rats were sacrificed 1 h after injection and 3 rats each on days 3, 6, 9, 12, 15, 18, 21 and 28 after injection. The eyes and eyelids were removed in one piece, fixed in formalin, embedded in paraffin and cut into 5-µm-thick vertical sections along the pupillary-optic nerve axis. The sections were dipped in liquid autoradiographic emulsion, exposed for 3 weeks, and stained with HE. Meibomian glands were scanned in the lower eyelid of the left eye using an ocular micrometer grid. In each scan the basement membrane of each acinus served as a point of origin. Along the entire gland two parameters were noted for each nucleus with three grains or more: the distance from the basement membrane (Y) and grain count. <i>Results: </i>This study demonstrates for the first time the exact timing and direction of meibomian gland cell migration. We have shown that the cells migrate from the basement membrane to the center of the acinus at an average rate of 0.62 ± 0.11 µm/day. Cell generation time was an average of 4.1 days. <i>Conclusions: </i>The stem cells of meibomian glands lie at the circumference of each acinus. These cells migrate synchronously with a constant velocity towards the center of the acinus, and are secreted as sebaceous material.
Specific Labeling of Lens Aldehyde Dehydrogenase Class 1 from <sup>3</sup>H-Cholesterol or Its Derivatives
Authors: Cenedella Richard J. 
Published: April 2003

We investigated the possibility that sterols could covalently modify ocular lens cell proteins. Incubation of cultured bovine lens epithelial cells (BLEC) with <sup>3</sup>H-cholesterol led to the labeling of a cytosolic protein of about 52 kD. Two-dimensional electrophoresis of the BLEC soluble proteins and fluorography revealed one labeled protein of 52 kD, pI = 6.6, plus a weakly labeled, slightly more acidic protein of the same size. MALDI-MS analysis of both proteins recovered from duplicate gels indicated both to be aldehyde dehydrogenase class 1 (ALDH-1). The identity was confirmed by immunoprecipitation with antiserum to ALDH-1. Alkaline hydrolysis of <sup>3</sup>H-labeled ALDH-1 released most of the radiolabel as compounds much more polar than cholesterol. We speculate that lens ALDH-1 can participate in the oxidation of cholesterol or its derivatives to unidentified sterol carboxylic acids and that the labeled protein reflects capture of ALDH-1 with sterol intermediates covalently bound to the enzyme in ester linkage. Lens ALDH-1 might, therefore, participate in the detoxication of polar sterols.