bluuebunny/crossref_metadata_2025 huggingface dataset:
Diazepam Increases the Number of Punished Responses in a Conflict-Operant Paradigm during Late Proestrus and Estrus in the Wistar Rat
Authors: Molina-Hernández Miguel , Contreras Carlos M. , Téllez-Alcántara Patricia
Published: April 2003

Both anxiety-like behavior and the response to anxiolytic drugs vary according to the estrus cycle in the rat. Consequently, anxiety-like behavior and the sensitivity to anxiolytic drugs may be related to hormone level fluctuations occurring during the estrus cycle. In male rats tested in a conflict-operant paradigm, anxiolytic drugs increase immediate punished responding. However, it is unknown whether estrus phases impinge on the immediate punished responses in a conflict-operant paradigm. Therefore, in this study female rats were trained in a conflict-operant paradigm; after training all animals received vehicle or diazepam. Then the number of immediate punished reinforcers was evaluated during the estrus cycle. Results showed that vehicle-treated rats evaluated during late proestrus and estrus obtained a higher (p < 0.05) number of immediate punished reinforcers than rats evaluated during metestrus and diestrus. A low dose of diazepam (1.3 mg/kg; i.p) significantly increased (p < 0.05) the immediate punished responses only in late proestrus and estrus. The highest dose of diazepam tested (2.0 mg/kg; i.p.) significantly increased (p < 0.05) the immediate punished reinforcement in any estrus phase. These results suggest that a lower level of anxiety-like and an increased sensitivity to an anxiolytic drug occurred only in late proestrus and estrus in rats tested in a conflict-operant paradigm.
Insomnia and Alpha Sleep in Chronic Non-Organic Pain as Compared to Primary Insomnia
Authors: Schneider-Helmert D. , Whitehouse I. , Kumar A. , Lijzenga C.
Published: April 2003

A considerable proportion of chronic non-organic pain patients suffer from insomnia, and alpha sleep has been suggested to be specifically associated with fibromyalgia. However, the clinical significance of those symptoms is not clear. This study was carried out to investigate this question. Twenty-six middle-aged, non-organic pain patients complaining of persistent insomnia were compared with 25 chronic primary insomniacs in a polysomnographic investigation. Alpha sleep was measured by automatic EEG analysis. A postsleep inventory allowed a separation of those pain patients with actual pain in the recording night to examine its possible influence on sleep. Both groups of patients displayed severe disturbance of sleep maintenance. The pain group did not differ in any of the insomnia variables or in sleep stages from chronic primary insomniacs. The occurrence of alpha sleep was high in either group which suggests that this is not a phenomenon specifically related to pain syndromes. A comparison of the pain subgroups revealed no difference between those with or without actual pain in the recording night. It is concluded that insomnia in chronic pain is of the same type and degree as primary insomnia. Apparently, the chronic process made insomnia so persistent that there was no response to actual night-time pain. Our study suggests that the interpretation of insomnia as secondary to pain, as it is usually made by the pain patients themselves, is a misattribution. It is suggested that insomnia in chronic pain patients should be taken seriously and treated by its specific methods.
The Prolonged P300 Latency in Recently Detoxified Alcohol-Dependent Patients Is Related to Activation of the Inflammatory Response System
Authors: Maes Michael , van West Dirk , Nuyten Dirk , Neels Hugo , De Vos Nathalie , De Bruyne Stephan , Degroote Johan
Published: April 2003

The aims of this study were to examine the late components of the auditory event-related potentials (AERPs), i.e. N100, P200 and P300, in recently detoxified alcohol-dependent patients compared to normal controls and to investigate whether there is a relationship between alterations in these AERPs and signs of activation of the inflammatory response system (IRS). The study subjects consisted of 14 healthy volunteers and 14 recently detoxified alcohol-dependent patients. All subjects performed a two-tone auditory discrimination task, using a standard ‘oddball’ paradigm. The alcohol-dependent patients had their blood sampled to examine IRS markers, such as erythrocyte sedimentation rate (ESR), serum copper concentrations and the number of leukocytes. The P300 latency was significantly greater in recently detoxified alcohol-dependent patients than in normal controls. There were significant correlations between the P300 latency and the ESR (r = 0.84, p = 0.009), serum copper concentrations (r = 0.73, p = 0.01) and number of monocytes (r = 0.71, p = 0.006). It is concluded that the P300 latency is prolonged in detoxified, chronic alcohol-dependent patients and is positively related to indicators of IRS activation. It is hypothesized that activation of the IRS may play a role in the delayed P300 latency in recently detoxified, alcohol-dependent patients.
Effects of Systemic Injections of Dopaminergic Agents on the Habituation of Rats Submitted to an Open Field Test
Authors: Furlan S.M. , Brandão M.L.
Published: April 2003

Many studies have reported that systemic injections of dopaminergic drugs result in profound changes in the behavior of animals in the open field. At the same time, it is hypothesized that increased brain dopaminergic activity prevents animals from habituating to a novel environment, and this effect would be responsible for the conditioned hyperactivity observed when rats are tested later in a drug-free state. However, little is known on the concurrent effects of these drugs, on learning processes and motor activity. To examine this issue, in the present study we assessed the effects of injections of the dopamine (DA) agonists amphetamine and apomorphine, the receptor antagonist chlorpromazine and the atypical neuroleptic clozapine on exploratory activity and habituation in rats exposed to the open field test. The observer scored the occurrence of animal behavior during three postinjection observation periods (0–5, 5–10 and 10–15 min). The results confirmed that amphetamine and apomorphine lead to a dose-dependent behavioral activation, while chlorpromazine produces an opposite effect, extending previous accounts of behavior of systemic-injected rats with these drugs. Independent of the level of motor activity, higher or lower than the control groups, habituation still occurs following DA agonists (amphetamine and apomorphine) and antagonist (chlorpromazine) injections in rats submitted to the open field test. Furthermore, the reduction of the exploratory activity over time in the open field after clozapine was less pronounced than in controls, in contrast to classical DA agents. The present results suggest that activation of DA mechanisms is involved in species-typical behaviors associated with exploratory behavior, but does not seem to be involved in non-associative learning processes, such as habituation. These effects could not be attributed to the decline in brain levels of the drugs during the session, as the behavioral activation remained high in rats previously habituated and injected with dopaminergic agonists within the same protocol. On the other hand, the atypical DA blocker clozapine reduced the expression of habituation, opening the possibility of involvement of alternative mechanisms, such as 5-HT mechanisms, in this non-associative learning process.
The Glutamate Antagonist Riluzole and Its Effects upon Basal and Stress-Induced Activity of the Human Hypothalamus-Pituitary- Adrenocortical System in Elderly Subjects
Authors: Kniest Anja , Wiesenberg Cornelia , Weber Bettina , Colla Michael , Heuser Isabella , Deuschle Michael
Published: April 2003

There is preclinical evidence that CRH is released in response to a glutamatergic stimulation. However, it is not clear, whether glutamate plays a role in the physiological stress response. We tested whether the antiglutamatergic drug riluzole dampens the response of the hypothalamus-pituitary-adrenocortical (HPA) system to both a mental and a physical stressor. Nine male elderly healthy subjects received placebo and 150 mg riluzole for 2 days in a randomized balanced order. Blood was withdrawn every 15 min for estimation of cortisol and ACTH from 14.00 to 20.00 h. Between 16.00 and 16.45 h, the subjects were subjected to a cognitive challenge paradigm. Further, between 19.02 and 19.15 an individually adapted physical stress test was performed. After riluzole treatment, baseline ACTH and cortisol concentrations were unchanged when compared to placebo treatment. Also, after the mental stressor, there was no difference between both treatment conditions. In contrast, the cortisol (riluzole vs. placebo: 148 ± 60 vs. 183 ± 98 nmol/l) and ACTH response (20.2 ± 11.9 vs. 40.7 ± 61.9 pmol/l) to the physical stressor tended to be lower after riluzole pretreatment. In conclusion, the antiglutamatergic drug riluzole did not have any effects upon HPA system activity under baseline and cognitive-stress-induced conditions in elderly subjects. However, a trend for dampening the endocrine response to physical stress emerged.
Effects of Haloperidol Pretreatment on the Smoking-Induced EEG/Mood Activation Response Profile
Authors: Walker Darlene , Mahoney Colleen , Ilivitsky Vadim , Knott Verner J.
Published: April 2003

This study examined the role of dopamine in modulating the CNS response to cigarette smoking. In a randomized, double-blind, repeated-measures design, quantitative electroencephalographic (EEG) changes and self-reports induced by the smoking of a single cigarette were assessed in 16 smokers following pretreatment with placebo and a dopamine antagonist, haloperidol (2 mg). Following placebo pretreatment, absolute (µV) and relative (%) amplitudes in slow-frequency bands (δ, Θ, α1) were reduced and absolute and relative amplitudes in fast-frequency bands (α2, β) were increased following cigarette smoking as compared to sham smoking. Haloperidol pretreatment inhibited the smoking-induced increase in absolute β frequency. Self-ratings indicated that cigarette smoking induced increases in alertness, contentedness and calmness but not euphoria, and reduced cigarette cravings as compared to the sham smoking conditions. Smoking-induced, α2 increments were associated with increases in alertness and decreases in euphoria while β increments were associated with increased calmness. Smoking-related self-ratings of mood and cigarette acceptability were not altered by haloperidol, but subjects were less content overall in the haloperidol condition as compared to placebo. Discussion of these results focuses on transmitter systems and their relationship to neuro-electric and behavioural activities associated with the smoking habit.
Serotonin 6 Receptor Polymorphism in Schizophrenia: Frequency, Age at Onset and Cognitive Function
Authors: Chiu Hsien-Jane , Wang Ying-Chieh , Liou Jiang-Hwa , Chao Ching-Han , Lee Huan , Tsai Kuan-Yi , Liu Win-Chien
Published: April 2003

The relative abundance of serotonin 6 receptor (5HT6) in some limbic regions and the high affinity of some antipsychotics for 5HT6 suggest that the 5HT6 gene might play a role in the pathogenesis of schizophrenic disorders. A recent study reported an association between a C267T polymorphism of the 5HT6 gene and schizophrenia. In order to test whether the 5HT6 gene plays a role in the pathogenesis of schizophrenic disorders, patients (n = 148) and control subjects (n = 160) were genotyped for 5HT6. We also investigated the relationship between genotypes and patients’ age at onset and cognitive function in schizophrenic patients. Cognitive function in the patients was evaluated by the Mini-Mental State Examination (MMSE). The results demonstrated no significant differences in genotype or allele frequencies between controls and patients. In the patient group, age at onset and MMSE score did not differ significantly among the three 5HT6 genotpyes. The results of this study suggest that the 5HT6 C267T polymorphism plays no major role in susceptibility to the development of schizophrenia and is not related to cognitive impairment or age at onset in schizophrenic patients. Further studies of the relation between 5HT6 polymorphism and the symptoms and the therapeutic response in schizophrenic patients may help to elucidate the role of 5HT6 in the pathogenesis of schizophrenia.
Multimodal Electroneurophysiological Studies of Systemic Lupus erythematosus
Authors: Khedr Eman M. , Khedr Tayseer , Farweez Hassan M. , Abdella Gamal , El Beih Esam A.S.
Published: April 2003

The purpose of this study was to obtain electrophysiological documentation of possible involvement of central and peripheral nervous system (CNS and PNS) in systemic lupus erythematosus (SLE) patients even in the absence of neurological manifestations. The study included 30 consecutive patients with SLE and 25 age- and sex-matched volunteers as a control group. They were subjected to neurological and rheumatological tests and an extensive battery of neurophysiological tests, besides Wechsler adult intelligence scale. Overt neurological manifestations were observed in 14 patients (46.7%). Neurophysiological data revealed that 25 patients (83%) had at least 2 abnormal tests; 11 (68.8%) patients of the asymptomatic group and 14 patients (100%) of the symptomatic group with no significant differences between them. Seventeen patients (56.7%) had evidence of PNS dysfunction either in nerves (46.7%) or muscles (10%); 7 of them in the asymptomatic group. Twenty-four patients (80%) had evidence of CNS dysfunction. Twenty-two patients (73%) had abnormalities recorded on electroencephalography; 9 patients in the asymptomatic group and 13 patients in the symptomatic group. Eleven patients (37%) had abnormal values of P100 of visual evoked potential; 5 patients in the asymptomatic group and 6 in the symptomatic group. Eight patients (26.7%) had abnormal latency of wave I of brain stem response; 3 of them in the asymptomatic group. Abnormal prolongation of the P300 component of event-related potentials was recorded in 2 patients (12.5%) of the asymptomatic group, while low IQ was observed in 8 patients of each group. Neurophysiological abnormalities are fairly common in SLE patients whether symptomatic or asymptomatic. The use of such tests favors a true incidence of nervous system involvement, more accurate diagnosis, and may lead to better clinical care before the development of debilitating CNS and PNS changes.
Differential Effects of Age on Brain Gray Matter in Bipolar Patients and Healthy Individuals
Authors: Brambilla Paolo , Harenski Keith , Nicoletti Mark , Mallinger Alan G. , Frank Ellen , Kupfer David J. , Keshavan Matcheri S. , Soares Jair C.
Published: April 2003

This study examined possible differences in total gray and white matter brain content in bipolar patients and healthy individuals, and their relationship with age. 22 DSM-IV bipolar patients and 22 healthy controls underwent a 1.5-tesla Spoiled Gradient Recalled Acquisition (SPGR) MRI. Evaluators blind to patients’ identities measured total brain, gray and white matter volumes using a semi-automated software. No differences were found for total brain volume, gray matter or white matter volumes between bipolar patients and healthy controls (MANCOVA, age as covariate, p > 0.05). Age was inversely correlated with total gray matter volume in patients (r = –0.576, p = 0.005), but not in controls (r = –0.193, p = 0.388). Our findings suggest that any existing gray matter deficits in bipolar disorder are likely to be localized to specific brain regions, rather than generalized. The inverse correlation between age and brain gray matter volumes in bipolar patients, not present in healthy controls, in this sample of mostly middle-aged adults, could possibly indicate more pronounced age-related gray matter decline in bipolar patients, and may be of potential relevance for the pathophysiology of the disorder.
Time Course of Intranasally Administered Cholecystokinin-8 on Central Nervous Effects
Authors: Pietrowsky Reinhard , Claassen Lars , Frercks Hauke , Fehm Horst L. , Born Jan
Published: April 2003

The gut and brain peptide cholecystokinin (CCK) exerts a number of central nervous effects. Among them are effects on attention and stimulus processing as revealed by modulations of event-related potentials (ERPs). In the present study the time course of central nervous effects after an intranasal administration of CCK-8 was investigated by means of ERPs. ERPs were recorded in an oddball paradigm 15, 30, 60, 90, 120, and 240 min after administration. Following the double-blind intranasal administration of CCK-8 and placebo, the late positive complex (LPC) of the ERP was significantly increased following CCK-8 compared to placebo. This effect was more pronounced in women than in men. The enhancement of the LPC by intranasal CCK-8 was not restricted to a specific recording time but reached its maximum 120 min after administration in men and women. Moreover, results tentatively indicate that 30 min after administration of CCK-8 the LPC increased only in women but not in men. The early effect of intranasal CCK-8 on LPC in women is unlikely to be caused by changes in plasma CCK-8 levels and suggests a direct nose-brain pathway.
Regional Cerebral Blood Flow in Patients Suffering from Post-Traumatic Stress Disorder
Authors: Mirzaei S. , Knoll P. , Keck A. , Preitler B. , Gutierrez E. , Umek H. , Köhn H. , Pecherstorfer M.
Published: April 2003

Objective: The aim of the study was to determine whether regional cerebral blood flow in survivors of torture suffering from post-traumatic stress disorder (PTSD) differed significantly from that in healthy controls. Method: We examined the cerebral regional distribution of 99m-technetium-hexamethylpropyleneamineoxime (HMPAO) using single photon emission computed tomography (SPECT) in 8 patients and in 8 healthy controls. A semi-quantitative analysis was performed in which symmetrical regions of interest (ROI) were drawn in all subjects. Results: Regional blood flow was markedly more heterogeneous in patients suffering from PTSD than in healthy controls. The differences are significant. Conclusion: Severe psychological trauma induced by torture can cause neurobiologic alterations that may contribute, even years after the original trauma, to a number of complaints commonly expressed by patients suffering from PTSD.
Association Study of Angiotensin-Converting Enzyme Gene Polymorphism with Schizophrenia and Polydipsia
Authors: Ouyang Wen-Chen , Wang Ying-Chieh , Hong Chen-Jee , Cheng Chih-Ya , Tsai Shih-Jen
Published: April 2003

Angiotensin-converting enzyme (ACE) is a key enzyme in the renin-angiotensin system and can modulate dopamine turnover in the midbrain. Previous studies have revealed changes in the central ACE levels for schizophrenic patients, possibly related to the polydipsia commonly demonstrated for chronic schizophrenia. An insertion (I)/deletion (D) polymorphism of the ACE gene has been associated with ACE levels. Therefore, we elected to investigate the ACE I/D polymorphism for 124 schizophrenic patients and 117 control subjects. No significant differences for the genotype distribution or the allele frequency were revealed comparing controls and schizophrenic patients. The ACE genotypes were not associated with onset age or psychiatric symptoms for the schizophrenic cases. A modest association was revealed for this ACE polymorphism and polydipsia diagnosis for these patients. Using bearers of the D allele as baseline, the ratio for I/I homozygote was 2.31 (95% CI 0.95–5.65). This association needs further replication as it may have implications for the pathogenesis and the treatment of polydipsia for schizophrenic patients.
Intraspinal Pressure Influences CSF Disposition of Tryptophan and 5-HIAA
Authors: Eklundh Thomas , Nordin Conny
Published: April 2003

Cerebrospinal fluid (CSF) concentrations of monoamine compounds are influenced by factors such as age, gender, height, body weight, tapping time, and atmospheric pressure. We have now examined the role of intraspinal pressure. Thirteen male volunteers underwent lumbar puncture in the right decubitus position without preceding strict bed rest. The intraspinal pressure was recorded, and monoamine precursors, transmitters, and metabolites were analyzed in two consecutively collected CSF fractions. Tryptophan in 12 ml of CSF and the 5-hydroxyindoleacetic acid concentration ratio [fraction II (7–12 ml CSF)/fraction I (0–6 ml CSF)] correlated with the intraspinal pressure. Hypothetically, the intraspinal pressure may be a confounding factor for a correct interpretation of CSF tryptophan and 5-hydroxyindoleacetic acid concentrations, and this is an issue that has to be addressed in future CSF studies.
Inhibition of K+-Evoked Release of Rat Striatal 5-Hydroxytryptamine by an Atypical Antidepressant: Trazodone
Authors: Hatsuda Satoshi , Sugita Sotaro , Suzuki Shigeru , Matsubara Momoyo , Ozaki Norio , Kayukawa Yuhei , Ohara Mitsugi
Published: April 2003

Using microdialysis, extracellular concentrations of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were determined in the striatum of rats. In rats given trazodone, m-chlorophenylpiperazine dihydrochloride, or imipramine, the concentrations of 5-HT were unchanged. 5-HIAA in trazodone- or imipramine-treated rats, however, was respectively, decreased to 80 or 65% of preinjections levels. When the potassium concentration (K+) was increased up to 150 mmol/l in the perfusate, the concentrations of 5-HT increased to about ten times the basal levels in the rats given saline. In rats treated with trazodone, K+-evoked elevations of 5-HT were less than five times the basal level. Multiple trazodone administrations prolonged the duration of inhibition of 5-HT release. In rats treated with other drugs, the K+-evoked 5-HT release was not affected. These observations suggest that trazodone itself might reduce 5-HT neural transmission.
Spatial Structure of Brain Electric Fields during Intermittent Photic Stimulation
Authors: Hirota Takuya , Yagyu Takami , Pascual-Marqui Roberto D. , Saito Naomi , Kinoshita Toshihiko
Published: April 2003

EEG changes in 27 young healthy male right-handed volunteers on intermittent photic stimulation (IPS) were estimated using global field power (GFP), EEG microstate modeling and analysis (EMMA), and low-resolution electromagnetic brain tomography (LORETA). The GFP significantly increased at flashing frequency and high harmonics. Three model maps were extracted with the EMMA procedure, from which high alternation rates of each microstate were observed. Moreover, two of the three model maps contributed very highly, occurring most frequently. LORETA imaging of the three model maps obtained from the EMMA procedure showed that both visual dominant cortical areas were activated, especially in the left hemisphere. These results suggest that IPS does not cause peculiar spatial configurations of the brain electric field, but does cause acceleration and deviation of the microstate alternation. Also, a functional laterality between hemispheres might be enhanced by symmetric IPS.
Morning and Evening Plasma Melatonin and Dexamethasone Suppression Test in Patients with Nonseasonal Major Depressive Disorder from Northern Greece (Latitude 40–41.5°)
Authors: Fountoulakis K.N. , Karamouzis M. , Iacovides A. , Nimatoudis J. , Diakogiannis J. , Kaprinis G. , Demitriadou A. , Bech P.
Published: April 2003

Introduction: The present study aimed to search for correlations between melatonin (MT) levels and the dexamethasone suppression test (DST) and clinical variables. Methods: Fifty depressed patients aged 21–60 years took part in the study. The Schedules for Clinical Assessment in Neuropsychiatry, version 2.0, and the International Personality Disorders Examination were used for diagnosis. Psychometric assessment included the Hamilton Depression Rating Scale, the Hamilton Anxiety Scale, the General Assessment of Funtioning Scale, the Newcastle scales and the Diagnostic Melancholia Scale. The DST and 9.00 and 23.00 h MT values were assessed. Statistical analysis included Student’s t test, Pearson product moment correlation coefficient and forward stepwise multiple linear regression analysis. Results: Melancholic patients had lower 23.00 h MT values in comparison to the rest of the patients and the atypical and ‘undifferentiated’ patients. Conclusion: The current study shows that low MT values were closely related to melancholic depression. Distinct quality of mood, psychomotor agitation or retardation and anorexia or weight loss seemed to be responsible for this relationship.
Glucose and Glucoregulatory Modulation of Memory Scanning, Event-Related Potentials and EEG in Elderly Subjects
Authors: Knott V. , Messier C. , Mahoney C. , Gagnon M.
Published: April 2003

Endogenous P300b event-related potential (ERP) and behavioral performance measures, extracted during a visual memory scanning task, and spectral indices of resting electroencephalographic (EEG) activity, were assessed in 12 healthy elderly adults before and after double-blind oral administration of a placebo or glucose (50 mg) beverage. Glucoregulation was estimated by deriving a recovery index to categorize subjects as having better (BR) or poorer (PR) blood glucose recovery. Although glucoregulatory status did not impact on EEG or task performance, PR subjects exhibited reduced P300b areas relative to BR subjects prior to beverage administration. Glucose did not alter P300b or memory scanning performance but, regardless of glucoregulatory status, it increased the EEG power in the slow alpha frequency band. The study results suggest that peripheral glucoregulation can influence neuroelectric measures of cognition and that the acute ingestion of glucose can modulate central arousal processes.
Plasma Biopterin Levels and Depressive State in Pregnancy and the Early Puerperal Period
Authors: Omura Izumi , Mizutani Masako , Goto Setsuko , Hashimoto Ryo , Kitagami Tomitsune , Miura Hideki , Ohta Tatsuro
Published: April 2003

Plasma total biopterin and tetrahydrobiopterin levels of 14 normal pregnant and 15 normal puerperal women (within 1 week after delivery) were measured. In the first group, total biopterin levels were already increased (average: 18.2 pmol/ml) in the second trimester and remained high until the early puerperal period. In the second trimester, the ratio of tetrahydrobiopterin to total biopterin levels decreased to 72.3% and even further to 66.1% in the third trimester. This tendency continued until the puerperal period. Compared with the control group (12 healthy nonpregnant women), total biopterin levels increased during pregnancy and the puerperal period (p < 0.001), and the ratio in the third trimester and the early puerperal period decreased (p < 0.001). The depressive state according to Zung’s score appeared most markedly in the third trimester with a mean score of 48, and tended to recover to a mean score of 36.2 in the early puerperal period. In this period, a correlation was found between Zung’s score and the total biopterin levels (r = 0.80), and the ratio of tetrahydrobiopterin levels to the total biopterin levels (r = –0.92). In the early puerperal period, total biopterin levels were higher in subjects with Zung’s scores ≧36 (p < 0.001); the ratios of this group were lower than those of subjects with Zung’s scores <36 (p < 0.001). Plasma biopterin levels in pregnancy and the early puerperal period closely resembled those of patients with mood disorders who show depressive symptoms from a psychoneurological perspective. Therefore, it seems possible that a depressive state in pregnancy and the early puerperal period has the same pathology as depression.
Marker Gene Transfer and Oncolysis of Human Y79 Retinoblastoma Cells Mediated by Herpes simplex Virus Mutants
Authors: Nicolò Massimo , Chiocca E. Antonio
Published: April 2003

Three different herpes simplex virus (HSV) mutants, designated hrR3, MGH-1 and R3616, were used to infect Y79 retinoblastoma cells grown in suspension. Two parameters were assayed: (a) vector-mediated gene expression, measured by histochemical staining of a transferred LacZ transgene, and (b) virus-mediated oncolysis, determined by the inability of infected cells to exclude trypan blue dye. The tested HSV mutants were found to infect cells grown in suspension at a relatively low multiplicity of infection (MOI = 0.01) and were capable of transferring the LacZ gene as early as 2 days after infection. Furthermore, differences in oncolytic activity were observed amongst the tested viruses: MGH-1 and R3616 exhibited 50% cell kill at a MOI of 0.1 over a period of 6 days, whereas hrR3-mediated oncolysis appeared less efficient. These studies provide a rationale for further exploitation of oncolytic herpes viruses as a potential treatment of intraocular tumors.
Pharmacological Mechanism of Topical Lodoxamide Treatment in Vernal Keratoconjunctivitis: A Flow-Cytometric Study
Authors: Murat Avunduk Avni , Cihat Avunduk Mustafa , Dayanır Volkan , Tekelioglu Yavuz , Selim Dayioglu Yavuz
Published: April 2003

The aim of this study was to investigate the possible effect of lodoxamide 0.1% ophthalmic solution (LOS) on tear T lymphocytes, especially Th2 (T helper 2 subgroup of helper T lymphocytes), in the tear specimens of patients with vernal keratoconjunctivitis (VKC) and to explore the mechanism of the anti-allergic effect of this drug. Twenty-eight active VKC patients were randomly divided into two groups each containing 14 patients. We obtained tear samples from all patients at the beginning of the study. LOS was prescribed to the study group (group A), but the controls (group B) received placebo over the course of 6 weeks. Tear samples were also collected from all patients following a 6-week course of treatment with either LOS or placebo. The percentages of Th1, Th2 and Th cells in the tear samples were measured by using a flow-cytometric technique and the results were compared to each other by using Wilcoxon matched-pairs signed-rank and Mann-Whitney U tests. We found that LOS treatment decreased the percentages of Th2 and Th cells in the tears of group A patients, while placebo had no effect on these values. Th1 cell count in the tears of both groups of patients did not show any significant change between the pre- and posttreatment stages. Our data suggest that LOS exerts, at least, some part of its anti-allergic effect via decreasing the Th2 cell number in the tears of VKC patients.
Pattern Electroretinogram Elicited by a Dartboard Pattern
Authors: Yoshii Masaru , Yanashima Kenji , Nakata Yasuhiko , Nozawa Fukumi , Okisaka Shigekuni
Published: April 2003

The receptive field size of retinal ganglion cells is closely related to their eccentricity from the fovea. To elicit larger pattern-reversal electroretinograms (P-ERGs), it may be useful to stimulate the retina with patterns having elements that parallel this change in receptive field size. We describe a dartboard pattern consisting of reversal elements that enlarge gradually from the central to the peripheral stimulus field. The utility of the dartboard pattern for eliciting P-ERG was investigated by comparing it with the conventional uniform checkerboard pattern, but with the other stimulus parameters remaining unchanged (96% contrast, 35.9 cd/m2 mean luminance, 3.3 rev/s temporal frequency, 15° circular field). The dartboard pattern produced a significantly larger P50 amplitude than did the checkerboard pattern, while no difference in peak latency was found when 54 min of arc was used as a standard check size for the checkerboard pattern. The dartboard pattern for eliciting P-ERG should prove clinically useful.
Cell Growth Inhibition and DNA Incorporation of Mitomycin C in Cell Culture
Authors: Takahashi Nobuo , Murayama Teiichirou , Oda Madoka , Miyakoshi Minoru
Published: April 2003

The present study was performed to clarify the effects of a 4-min exposure of mitomycin C (MMC) on cell growth, the cell cycle and MMC dose incorporated into DNA, using Chang’s cultured human conjunctival cells. A low dose of MMC ranging from 0.00025 to 0.004% showed dose-dependent cytotoxicity when cell growth was active. Fifty percent cell viability was found when cells were treated with 0.001% MMC. A flow cytometer showed that 0.001% MMC inhibited the DNA synthetic phase. After 0.04% MMC was exposed to 3 ×106 cells and immediately rinsed, DNA was isolated to measure the dose of MMC detected from DNA. The total amount of DNA was 7 µg from which 3 µg of MMC was detected by high performance liquid chromatography. The above results revealed that the lowest concentration of MMC which caused 50% cell viability and cell cycle inhibition was 0.001% and that MMC was rapidly incorporated into DNA.
Antiuveitis and Inhibition of Fibroblast-Like Corneal and Conjunctival Cell Cultures by Interleukin-1 Blockers, CK 125, CK 126 and CK 128
Authors: Xuan Bo , Chiou George C.Y. , Yamasaki Tetsuo , Okawara Tadashi
Published: April 2003

Three new interleukin-1 (IL-1) blockers, CK 125, CK 126 and CK 128, were studied for their effects on IL-1-induced uveitis in rat eyes. They were more potent (at 3–10 mg/kg t.i.d.) than prednisolone (20 mg/kg t.i.d.) in effectively inhibiting posterior uveitis. They were also found to inhibit fibroblast-like corneal cells at 10–300 µg/ml concentrations and conjunctival cells at 1–30 µg/ml levels. The incorporation of leucine into corneal and conjunctival cells was either stimulated or unaffected by CK 126, indicating that the inhibition of cell growth has nothing to do with the protein synthesis. However, the incorporation of uridine into corneal and conjunctival cells was markedly inhibited by CK 126 at 3–30 µg/ml concentrations whereas the incorporation of thymidine into the cells was inhibited at a lesser extent than that of uridine. These results indicate that cell inhibition by CK 126 could be related mainly to the synthesis of mRNA and, to a lesser extent, to DNA synthesis.
Effects of Pituitary Adenylate-Cyclase-Activating Polypeptide on the Direct-Current Electroretinogram of the Rabbit Eye
Authors: Jarkman Sven , Kato Masaru , Bragadóttir Ragnheiður
Published: April 2003

Pituitary adenylate-cyclase-activating polypeptide (PACAP) is a recently discovered neuropeptide present in two different forms, PACAP-27 and PACAP-38. Both peptides stimulate the catalytic enzyme adenylate cyclase in pituitary cells. This enzyme is important also regarding the function of the retinal pigment epithelium (RPE). The purpose of the study was to investigate possible influences of PACAP on the rabbit retina and the RPE as reflected in the direct-current (d.c.) electroretinogram (ERG) and the standing potential of the eye (SP). After unilateral sector vitrectomy, a continuous intraocular perfusion with a reference solution alternated with a test solution was established. The corneal d.c. ERG and the SP were recorded from both eyes with the contralateral eye as a control. Both PACAP-27 (0.1 and 1 µM) and PACAP-38 (1 µM) increased the c-wave amplitude significantly (p = 0.028, p = 0.013 and p = 0.024, respectively, n = 4) while neither PACAP-27 (0.1 and 1 µM, p > 0.05, n = 4) nor PACAP-38 (1 µM, p > 0.05, n = 4) produced any significant effects on the a- and b-wave amplitudes of the d.c. ERG. The SP response to the two substances differed with a significant elevation of the SP level with PACAP-27 (1 µM, p = 0.017, n = 4), while PACAP-38 induced a small, nonsignificant SP elevation (1 µM, p > 0.05, n = 4). Retinal penetrations during PACAP-27 (10 µM) perfusion showed an increase in transepithelial potential (TEP) c-wave (p = 0.003) as well as in slow PIII (p = 0.011, n = 3) amplitude level. The results support the presence of PACAP receptors both on the RPE and in the neural retina.
Scanning Electron Microscopy after Cryofracture of Normal and Ischemic Rat Retinas
Authors: Ménérath Jean Marc , Droy-Lefaix Marie-Thérèse , Doly Michel
Published: April 2003

The authors described the use of scanning electron microscopy after cryofracture to analyze rat retinas after experimental ischemia-reperfusion sequence. In Sprague-Dawley albino rats, intraocular hypertony by cannulation of anterior chamber was performed for 1 h on one eye. The other eye served as control. After 48 h of reperfusion, retinas were dissected. They were frozen and fractured before ultrastructural analysis by a scanning electron microscope. In the ischemic eyes the thickness of the photoreceptors layer was reduced, through internal disorganization resulting in misalignment of rods. There was swelling of the outer segments, a loss of adhesion between segments and superficial necrosis. Scanning electron microscopy after cryofracture permitted an analysis of the external morphology of retinal cells and intercellular components, especially the outer layers.
The Effect of Minoxidil on Keratocyte Proliferation in Cell Culture
Authors: McLeod Stephen D. , Alvi Nishat P. , Zhou Lili , Dave Yagnesh , Chandler John W. , Fiscella Richard
Published: April 2003

Purpose: To determine if minoxidil inhibits keratocyte proliferation in a nontoxic manner. Methods: Rabbit keratocytes were cultured in Eagle’s minimum essential medium supplemented with fetal bovine serum. Minoxidil varying in concentration from 10⁰ to 103 µg/ml was added to the culture medium and incubated for 7 days. The cultures were inspected for morphologic appearance and the cell number was determined at 1, 3 and 7 days after the addition of minoxidil. After 7 days of incubation, minoxidil was withdrawn from the cell culture medium and the cells were examined 3 and 7 days thereafter. In addition, a nonradioactive cytotoxic assay was performed to determine if toxicity is associated with the presence of minoxidil. Results: Minoxidil inhibited keratocyte proliferation in a dose-dependent fashion. 29% of control growth was achieved when keratocytes were cultured for 7 days in 103 µg/ml, whereas 82% control growth was achieved when keratocytes were cultured in 102 µg/ml of minoxidil. Intermediate concentrations between 102 and 103 µg/ml produced a linear decline in cell counts in a dose-dependent fashion. The concentration of minoxidil required for 50% control growth at 7 days extrapolated from the dose-response curve was 600 µg/ml. Upon withdrawal of minoxidil, cell counts returned to baseline for concentrations of 102 µg/ml or less. Phase contrast microscopy revealed that the presence of minoxidil was associated with intercellular separation, enlargement of cell bodies and elongated processes. After the withdrawal of minoxidil, the cells in all media reassumed the morphological features of normal keratocytes which included a regular fusiform shape and extensive intercellular contact. The nonradioactive cytotoxic assay revealed the lack of cytotoxicity at all concentrations of minoxidil based on a lack of lactate dehydrogenase release. Conclusions: Minoxidil inhibits keratocyte proliferation by a nontoxic mechanism. It might be particularly useful for modulating corneal wound healing following excimer laser photorefractive keratectomy.
Effect of Freezing on Lens Capsule Mechanical Behavior
Authors: Krag Susanne , Andreassen Troels T.
Published: April 2003

Postmortem storage of lens capsules by freezing was found to increase capsular thickness slightly (5%). The effect on mechanical properties was minor. Ultimate tensile strength and ultimate stiffness were not changed by freezing. Ultimate strain was slightly increased (2%) and the elastic modulus calculated at 40% strain was decreased (20%). Frozen capsules were found to relax to a slightly lower value than fresh ones (2%). The results show that freezing tends to soften the tissue, possibly due to an increased hydration. In spite of this effect, which has to be kept in mind, postmortem freezing seems to be an acceptable storage method when collecting tissue for biomechanical research.
Light Scattering in the Human Lens in Childhood and Adolescence
Authors: Wegener A. , Müller-Breitenkamp U. , Dragomirescu V. , Hockwin O.
Published: April 2003

The age-related increase in normal light scattering in the adult human lens has frequently been documented with Scheimpflug imaging techniques. There are only insufficient data on lens light scattering, however, from the first 2 decades of human life. After having obtained informed consent from their parents, the anterior eye segments of 26 children of both genders were documented with a Topcon SL-45 Scheimpflug camera on Kodak Tmax 400 ASA black-and-white film in 3 meridians. The age of the children, who had either a normal visual acuity or best corrected visual acuity, ranged from 4 to 18 years. Thirty minutes prior to photography, maximal mydriasis was induced by 3-fold instillation of Mydriaticum Roche®. Parallel to the Scheimpflug photographic documentation, all eyes were subjected to a basic ophthalmological examination. All images obtained were evaluated with microdensitometry as described earlier. The density data in young children demonstrate that there is very little light scattering in the central lens parts and only a faint zone of discontinuity apart from the 2 signals caused by the anterior and posterior capsules. Starting at the age of 14–15 years, the first separations occur in the zones of discontinuity, thus the first age-correlated increase in light scattering. The data obtained demonstrate that the development of light scattering in the young lens differs from that in the adult lens. Our results point to the assumption that the development of protein light scattering in the lens correlates with physical life-time of the individual and not with the period of life in different species with various life expectancies.
Transforming Growth Factor Beta Induces Urokinase Receptor Expression in Cultured Retinal Pigment Epithelial Cells
Authors: Sirén Vappu , Myöhänen Heli , Vaheri Antti , Immonen Ilkka
Published: April 2003

The effect of transforming growth factor-β1 (TGF-β1) and interferon-γ (IFN-γ) was studied on urokinase receptor (uPAR) expression of cultured human retinal pigment epithelial (RPE) cells. Human RPE cells were incubated with 1, 5 or 10 ng/ml of TGF-β1 or with 10, 100 or 1,000 IU/ml of IFN-γ to measure total cellular uPAR protein and released uPAR by enzyme immunoassay. uPAR at cell surface was measured by flow cytometric analysis at 8, 12, 24 and 48 h. uPAR mRNA levels were assayed by Northern blotting at 2, 6, 12 and 24 h. The increase in uPAR gene expression in RPE cells exposed to TGF-β1 paralleled enhanced uPAR level at the cell surface and in conditioned medium. TGF-β appeared to induce also membrane-bound uPA activity and the release of active plasminogen activator inhibitor-1, indicating that TGF-β has the potential to regulate plasminogen activation at the RPE cell surface. The increase in uPAR gene expression by IFN-γ did not seem to translate into the protein level. We conclude that TGF-β regulates the pericellular proteolysis in RPE cells by increasing uPAR expression.
Investigation of Luminal Surface Structures of Rod Photoreceptor Outer Segments by Lectin Cytochemistry Combined with Freeze-Etching
Authors: Ishikawa Makoto , Tonosaki Akira , Abe Tohru , Sakuragi Shozo
Published: April 2003

The luminal surface of the rod photoreceptor disk membrane was exposed by means of osmotic shock and labeled with ferritin- conjugated concanavalin A. The structural changes of the luminal surface were examined by a freeze-etching procedure with cryoprotectant (methanol). On replicas from freeze-etched membranes with concanavalin A labeling, 6- to 10-nm particles were codistributed with ferritin particles on the luminal surface of the disk membrane. By contrast, there were few ferritin particles or less numerous 6- to 10-nm particles on the corresponding surface without concanavalin A labeling. If 6- to 10-nm particles corresponded to the carbohydrate moiety of rhodopsin, concanavalin A binding might tend to preserve this carbohydrate moiety. These results suggest that the two-dimensional analysis of lectin-induced structural changes of the membrane surface glycoconjugates may become available by lectin cytochemistry combined with freeze-etching.
Development of a Completely Encapsulated Intraocular Pressure Sensor
Authors: Walter Peter , Schnakenberg Uwe , vom Bögel Gerd , Ruokonen Peter , Krüger Clemens , Dinslage Sven , Lüdtke Handjery Hans Christian , Richter Horst , Mokwa Wilfried , Diestelhorst Michael , Krieglstein Günter K.
Published: April 2003

A completely encapsulated intraocular pressure (IOP) sensor equipped with telemetric signal and energy transfer is introduced integrated into a silicone disc for implantation into the eye. After implantation into enucleated pig eyes and into rabbit eyes in vivo, the IOP was recorded and compared to established techniques of IOP measurement. Pressure chamber tests showed that the sensor functioned correctly after biocompatible encapsulation in polydimethylsiloxane. In vivo and in vitro tests in rabbit and pig eyes demonstrated that the implanted system worked with the same precision as established techniques for IOP determination. The correlation between the measurements with the implanted device and pneumotonometry in several experiments was between 0.9 and 0.99. This device serves as a functioning model for the realization of a telemetric IOP sensor for integration into an artificial intraocular lens. Such a device will open new perspectives, not only in the management of glaucoma, but also in basic research for mechanisms of glaucoma.
Serum Methanol Levels in Subjects with or without Optic Nerve Head Disease
Authors: Hayasaka Yoriko , Hayasaka Seiji , Hiraki Shigeyoshi , Kadoi Chiharu , Nagaki Yasunori , Matsumoto Masayuki
Published: April 2003

We evaluated serum methanol levels in subjects with or without optic nerve head disease. Serum methanol levels were determined using gas chromatography in 71 patients with optic nerve head disease and in 127 subjects without optic nerve head disease. Their ages ranged from 17 to 89 years. Serum methanol levels in 127 subjects without optic nerve head disease ranged from 0.12 to 3.86 µg/ml (mean ± standard deviation, 1.72 ± 0.86 µg/ml). In the subjects without optic nerve head disease, the differences in the levels between those with cataract versus retinal detachment, men versus women, and between each age-group (50–80 years) were not significant. The methanol levels in patients with optic neuritis (n = 2), Wolfram syndrome (n = 1), Leber hereditary optic neuropathy at the late stage (n = 2), retinitis pigmentosa (n = 23), and primary open-angle glaucoma (n = 16) were less than 3.86 µg/ml. Methanol levels in 1 patient with Leber hereditary optic neuropathy at the acute stage was 5.28 µg/ml. Of 10 patients with primary angle-closure glaucoma, 1 had a slightly elevated level and 9 had levels less than 3.86 µg/ml. Of 17 patients with normal tension glaucoma, 5 had methanol levels higher than 3.86 µg/ml, and 12 patients had levels less than 3.86 µg/ml. The present study shows that serum methanol levels in subjects without optic nerve head disease ranged from 0.12 to 3.86 µg/ml and were much lower than the levels that produce acute ocular symptoms of methanol intoxication. It is possible that high serum methanol levels may play a part in the acute stage of Leber hereditary optic neuropathy and normal tension glaucoma in certain patients. It is unlikely that increased serum methanol levels participate in primary angle-closure glaucoma.