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Biomedical subjects

M Radwan

Publications and source records attributed to M Radwan.

At least 19 recordsLinked to original sources
PubMed2006

Comparison of reactive oxygen species concentration in seminal plasma and semen parameters in partners of pregnant and non-pregnant patients after IVF/ICSI.

The aims of this study were (i) to determine and compare the concentration of reactive oxygen species (ROS) and total antioxidant status (TAS) in seminal plasma and sperm parameters of the male partners of patients undergoing IVF or intracytoplasmic sperm injection (ICSI) treatment and (ii) to establish the relationship between ROS and TAS concentrations and sperm quality and their effect on fertilization and pregnancy rate of patients who achieved a pregnancy and those who were unsuccessful. Twenty-six IVF and 22 ICSI patients were included in this study. The ROS concentration in seminal plasma and sperm concentration, vitality (eosin test), motility, morphology, membrane integrity (HOS test), maturity (chromomycin, CMA3) and DNA fragmentation (TUNEL) results and their relationship to fertilization and pregnancy were analysed. ROS concentrations were similar regarding the seminal plasma of male partners of patients who achieved a pregnancy and those who were unsuccessful. The other semen parameters, concentration, motility, vitality, membrane and DNA integrity, were comparable in both groups. However, both groups demonstrated a negative correlation between ROS concentration and sperm vitality, membrane integrity and morphology. Moreover, an inverse correlation was found between TUNEL, vitality, and membrane integrity. In conclusion, ROS concentration in seminal plasma affects the quality of spermatozoa. A negative correlation between the ROS concentration in seminal plasma and fertilization rate in both IVF/ICSI programmes was shown.

Adult↗
PubMed2006

Novel growth of aluminium nitride nanowires.

This work describes novel growth of aluminium nitride (AIN) nanowires by nitridation of a mixture consists of aluminium and ammonium chloride powders (Al:NH4Cl = 1.5:1 weight ratio) at 1000 degrees C for 1 h in flowing nitrogen gas (1 l/min). XRD analysis of the product showed the formation of pure hexagonal AIN. SEM micrographs of as-synthesized product revealed the growth of homogeneous AIN nanowires (phi 40-150 nm). No droplets were observed at the tips of obtained nanowires which suggests that they were grown mainly by a vapor-phase reactions mechanism. Thermodynamic analysis of possible intermediate reactions in the operating temperatures range illustrates that these nanowires could be grown via spontaneous vapor-phase chlorination-nitridation sequences.

Aluminum Compounds↗
PubMed2001

Numerical analysis of the transport and fate of nitrate in the soil and nitrate leaching to drains.

In this study, the transport and fate of nitrate within the soil profile and nitrate leaching to drains were analyzed by comparing historic field data with the simulation results of the DRAINMOD model. The nitrogen version of DRAINMOD was used to simulate the performance of the nitrogen transport and transformation of the Hooibeekhoeve experiment, situated in the sandy region of the Kempen (Belgium) and conducted for a 30-year (1969-1998) period. In the analysis, a continuous cropping with maize was assumed. Comparisons between experimentally measured and simulated state variables indicate that the nitrate concentrations in the soil and nitrate leaching to drains are controlled by the fertilizer practice, the initial conditions, and the rainfall depth and distribution. Furthermore, the study reveals that the model used gives a fair description of the nitrogen dynamics in the soil and subsurface drainage at field scale. From the comparative analysis between experimental data and simulation results it can also be concluded that the model after calibration is a useful tool to optimize as a function of the combination "climate-crop-soil-bottom boundary condition" the nitrogen application strategy resulting in an acceptable level of nitrate leaching for the environment.

Agriculture↗
PubMed2001

Modeling of nitrogen in river water using a detailed and a simplified model.

To model catchment surface water quantity and quality, different model types are available. They vary from detailed physically based models to simplified conceptual and empirical models. The most appropriate model type for a certain application depends on the project objectives and the data availability. The detailed models are very useful for short-term simulations of representative events. They cannot be used for long-term statistical information or as a management tool. For those purposes, more simplified (conceptual or meta-) models must be used. In this study, nitrogen dynamics are modeled in a river in Flanders. Nitrogen sources from agricultural leaching and domestic point sources are considered. Based on this input, concentrations of ammonium (NH4-N) and nitrate (NO3-N) in the river water are modeled in MIKE 11 by taking into consideration advection and dispersion and the most important biological and chemical processes. Model calibration was done on the basis of available measured water quality data. To this detailed model, a more simplified model was calibrated with the objective to more easily yield long-term simulation results that can be used in a statistical analysis. The results show that the conceptual simplified model is 1800 times faster than the MIKE 11 model. Moreover the two models have almost the same accuracy. The detailed models are recommended for short-term simulations unless there are enough data for model input and model parameters. The conceptual simplified model is recommended for long-term simulations.

Agriculture↗
PubMed2000

Different effects of nabilone and cannabidiol on binocular depth inversion in Man.

The physiological and pathophysiological roles of the central nervous endogenous cannabinoid system are not completely understood, but still represent a challenge in basic neurobiological, cognitive, and psychiatric research. The system has been implicated in the pathogenesis of schizophrenia. Binocular depth inversion, an illusion of visual perception, provides a model of impaired perception during psychotic states. Using this model the effects of nabilone, a psychoactive synthetic 9-trans-ketocannabinoid, and of cannabidiol, the main natural component of herbal cannabis, and a combined application of both substances on binocular depth inversion and behavioural states were investigated in nine healthy male volunteers. The time course of the effects of both substances on binocular depth inversion was analysed after oral administration using three different groups of natural stimuli. A significant impairment of binocular depth perception was found when nabilone was administered, but combined application with cannabidiol revealed somewhat reduced effects on binocular depth inversion. The influence of psychoactive cannabinoids on this perceptual model and the role of the endogenous cannabinoid system in visual information processing are discussed.

Adult↗
PubMed1999

Homicide by schizophrenic patients in Israel.

Thirty-three schizophrenic inpatients aged 45.3 +/- 13.5 years who had been found not guilty of homicide by reason of insanity were compared with 28 schizophrenic patients matched for age, sex and duration of disease who had not committed any crime. Statistical analysis revealed a high rate in the study group of individual factors associated with aggression, such as alcohol abuse, previous contact with the police, aggressive behavior and threats (P < 0.05). Significantly more of them were also immigrants (P < 0.05). There was no between-group difference in familial factors. These findings support earlier studies indicating that schizophrenic patients with the profile of alcoholism, aggressiveness and foreign country of origin are at high risk of homicidal behavior.

Adolescent↗
PubMed1998

The effects of tetrahydrocannabinol on the recognition of emotionally charged words: an analysis using event-related brain potentials.

The effects of synthetic tetrahydrocannabinol (THC) on event-related brain potentials (ERPs) were assessed in 19 healthy male volunteers while they performed a visual continuous word recognition task. The study used a double-blind cross-over design. Specifically, word lists were manipulated to contain an equal number of emotionally neutral, negative, and positive words. Most words were repeated after several intervening items with the subject's task to classify each word as old (previously seen) or new. Behaviorally, a decrease in recognition rate was observed under THC but no influence of the emotional charge of a word on recognition rate was seen. The ERPs showed a typical difference between old and new words taking the form of an enhanced positivity for old words beginning 250 ms poststimulus. The effects of THC were confined to the positive words, for which an enhancement of the positivity to the old words was seen. This effect was interpreted in terms of a congruity of the drug-induced mood state and the material to be recognized. The dissociation between ERPs and behavioral indices suggested that the former primarily reflect implicit memory processes.

Adult↗
PubMed1997

Sulpiride augmentation in people with schizophrenia partially responsive to clozapine. A double-blind, placebo-controlled study.

BACKGROUND: We hypothesised that a combined regimen of clozapine, a relatively weak D2-dopaminergic antagonist, and sulpiride, a selective D2 blocker, would demonstrate a greater antipsychotic efficacy by enhancing the D2 blockade of clozapine. METHOD: Twenty-eight people with schizophrenia, previously unresponsive to typical antipsychotics and only partially responsive to current treatment with clozapine, received, double-blind, 600 mg/day sulpiride or placebo, in addition to an ongoing clozapine treatment. The clinical status was evaluated before, during, and at the end of 10 weeks of sulpiride addition using the Brief Psychiatric Rating Scale (BPRS), Scale for the Assessment of Positive Symptoms (SAPS), Scale for the Assessment of Negative Symptoms, and Hamilton Rating Scale for Depression. RESULTS: The clozapine-sulpiride group exhibited substantially greater and significant improvements in positive and negative psychotic symptoms. About half of them, characterised by a younger age and lower baseline SAPS scores, had a mean reduction of 42.4 and 50.4% in their BPRS and SAPS scores, respectively. CONCLUSIONS: A subgroup of patients with chronic schizophrenia may substantially benefit from sulpiride addition to clozapine.

Adult↗
PubMed1996

[Anorexia nervosa beginning after the menopause].

Anorexia nervosa (AN) in older patients is not often described. We present a 70-year-old woman with AN which started at the age of 50 after her menopause. We suggest that AN starting after the menopause is a unique disturbance with characteristics different from those in younger age groups. The causes of anorexia in the older patient and its special dynamics should be recognized. It may be necessary to create a different diagnostic system and devise special treatment for AN in post-menopausal women.

Age of Onset↗
PubMed1995

First month of neuroleptic treatment in schizophrenia: only partial normalization of the late positive components of visual ERP.

In a previous study we recorded visual event-related potentials (ERP) in drug-naive schizophrenics during passive-attention and active-attention tasks. Patients, compared to normal controls, had much lower late positive components (LPC) in both sessions, but nearly normal LPC increase from passive to active task. The present sample consisted of drug-naive and drug-free patients who were tested before and during the first month of neuroleptic treatment. Neuroleptics initiated gradual amelioration of psychiatric symptoms expressed by reduced Brief Psychiatric Rating Scale (BPRS) scores. Schizophrenics compared to controls showed a session-related increase in LPC amplitude, but this process of LPC recovery was too minor to fully normalize the low LPC amplitudes in patients. Furthermore, the treatment either did not improve or even reduce the LPC reaction to the active-attention task. These findings indicate that normalization of low LPC in schizophrenia might require a long period of treatment, and that patients' reduced LPC reactivity to the task might be contributed, rather than treated, by neuroleptics.

Adult↗
PubMed1995

Antinuclear autoantibodies in chronic schizophrenia.

We determined the presence of antinuclear autoantibodies (ANA), antinative DNA and histone-reactive ANA in 3 groups of chronic schizophrenic patients (n=85): haloperidol-treated patients (for at least 3 months) (n=35), drug-free for at least 3 months (n=35) and neuroleptic-naive patients (n=15). The autoantibody titers were compared with those of healthy controls (n=37). A significantly higher frequency of positive ANA was found among chronic schizophrenic patients (approximately 20%) as compared with the controls (approximately 5%), irrespective of drug treatment, sex and age. No antinative ANA autoantibodies or histone reactive ANA were detected in either schizophrenic patients or controls. Further studies are needed to isolate and characterize in ANA-positive schizophrenic patients a putative specific ANA profile.

Adult↗
PubMed1995

Catatonia as an unusual presentation of posttraumatic stress disorder.

A patient with posttraumatic stress disorder (PTSD) had several episodes of catatonia in the past 44 years. These episodes were characterized by a sudden onset of intense excitement, mild pyrexia, often moderate elevation of serum creatinine phosphokinase and the development of a full catatonic state. We could not relate the symptomatology exhibited to any one of the accepted etiologies of catatonia. We assume, following careful evaluation of the clinical picture, and thorough biochemical and imaging work-up, that in this case the catatonic states represented an overwhelming psychic response to associated traumatic recollections, bringing to extreme the avoidance, numbness and motor responses usually encountered in PTSD.

Aged↗
PubMed1995

Cyproheptadine treatment in neuroleptic-induced akathisia.

BACKGROUND: Cyproheptadine, an antiserotonergic agent, was used to treat neuroleptic-induced akathisia. METHOD: In an open clinical trial 17 neuroleptic-treated patients with akathisia were administered cyproheptadine (16 mg/day) over 4 days. Assessment of akathisia, psychosis and depression were monitored by BAS, BPRS and HAM-D. RESULTS: All subjects showed improvement in the severity of akathisia, which in the majority (15/17) was of a marked degree. There was no aggravation of psychosis or depression. Symptoms of akathisia returned when cyproheptadine was discontinued. CONCLUSIONS: Cyproheptadine may be useful in neuroleptic-induced akathisia.

Akathisia, Drug-Induced↗
PubMed1995

Evaluation of expanded program on immunization during the first year of life in Abu Dhabi.

This study was intended to highlight the program of vaccination in the first year of life against the Expanded Program on Immunization (EPI)-target diseases and to determine the trend of these diseases in Abu Dhabi during 1984-1989. The data were collected from annual reports of Ministry of Health. This retrospective study pointed out to the following results: (1) The average vaccination coverage (percent) during the first year of life against EPI-Target diseases increased gradually during 1984, 1986, 1987, 1988, 1989. (2) The vaccination coverage (percent) during the first year of life using BCG and measles vaccines are increased significantly (p < 0.001) during 1985-1989 compared with 1984. (3) The vaccination coverage (percent) during the first year of life using OPV and DPT at the third dose are increased significantly (p < 0.05) during 1987-1989 compared with 1984. (4) The reported cases of measles and its incidence rate consequently decreased during 1988-1989 compared with 1987 and the differences are statistically significant (p < 0.001). The reported cases of diphtheria and its incidence rate show significant increase (p < 0.01) during 1988 compared with 1984. Other EPI target diseases do not show any statistically significant difference (p > 0.05) during 1985-1989 compared with 1984. Based on this study it can be concluded that with increase in average vaccination coverage (percent) from 58.5% in 1984 to 82.9% in 1989, the number of reported cases of EPI target diseases decreased.

Communicable Disease Control↗
PubMed1994

Psychiatric aspects of hyperemesis gravidarum.

Hyperemesis gravidarum is a potentially dangerous disorder of pregnancy characterized by severe and protracted vomiting. It is suggested that psychosocial factors may have a role in determining whether the pregnant woman experiences a transient spell of mild vomiting or progresses towards the much rarer but more significant pernicious vomiting. Psychotherapy, hypnotherapy and behavior therapy have been reported to contribute to the treatment of patients with hyperemesis gravidarum. A review of the etiological factors as well as of the therapeutic approaches is presented.

Behavior Therapy↗
PubMed1993

Apparent velocity of ultrasound (AVU) at the patella in comparison to bone mineral density at the lumbar spine in normal males and females.

It has been reported that apparent velocity of ultrasound (AVU) at the patella discriminates as well between osteoporotic and normal subjects as measurement of bone mineral density (BMD) using dual photon absorptiometry. To investigate the relationship between AVU and peak bone mass, we compared AVU (Signet, Osteo-Technology, Framingham, MA) at the patella and BMD (QDR 1000, Hologic, Waltham, MA) at the lumbar spine in a large sample of healthy males and females. The study population consisted of 153 males (aged 20-60 years) and 129 premenopausal females (aged 20-52 years). Vertebral BMD showed no significant difference between males and females (1.03 +/- 0.16 g/cm2 for males vs. 1.07 +/- 0.14 g/cm2 for females, NS), while AVU values were significantly higher in males compared with females (1967 +/- 64 m/s vs. 1938 +/- 76 m/s, P < 0.05). In men there was a significant decrease in BMD with aging (r = -0.27, P < 0.05), in premenopausal females we found no age-related change in BMD. Similarly in males AVU decreased significantly with age (r = -0.2, P < 0.05), whereas in females AVU values showed relative stability over the age range. There was a significant correlation between AVU and BMD (r = 0.36 for males, r = 0.34 for females, P < 0.05). Our study demonstrates only a weak correlation between AVU at that patella and BMD at the lumbar spine, supporting the view that AVU not only reflects bone quantity but possibly also qualitative properties of bone structure. The sex difference in AVU but not in BMD suggests that the trabecular bone at the patella differs significantly from axial trabecular bone. The identical peak BMD at the lumbar spine for young males and females underscores the importance of the menopause for later manifestation of vertebral fractures.

Absorptiometry, Photon↗
PubMed1993

Reduced total complement haemolytic activity in schizophrenic patients.

Serum concentrations of the third and fourth components of the complement system and total complement haemolytic activity were measured in 167 psychiatric patients. Total complement haemolytic activity was decreased in chronic schizophrenic patients as compared to healthy controls and bipolar patients. The relatively diminished total haemolytic activity was not attributable to drug treatment. It is not clear if the reduced total haemolytic activity is an epiphenomenon or related to the involvement of an autoimmune process in the pathophysiology of schizophrenia.

Autoimmune Diseases↗