Effect of ondansetron for preventing of ovarian hyperstimulation syndrome: in an experimental rat model.

Objective: Ovarian hyperstimulation syndrome is an iatrogenic condition that occurs in the treatment of infertility. There is no specific treatment available for OHSS. Cabergoline is a dopamine receptor 2 agonist and VEGF-VEGF2 receptor antagonist . Recently, cabergoline has been widely used to prevent the development of OHSS and reduce its severity Serotonin is known as a neurotransmitter and thought to have a role in the mechanism of angiogenesis and in signaling in endothelial cells. Serotonin is said to have similar effects to VEGF . Ondansetron is Selective Serotonin (5-HT3) Receptor Antagonist . It works by blocking the action of serotonin, a natural substance that may cause nausea and vomiting. In the clinical practice today, there is no choice other than cabergoline, to prevent occurrence and reduce severity of OHSS, and sometimes its effects are limited. Methods: In our study, we compared the effect of cabergoline and ondansetron. 32 immature rats were used and the OHSS model was created. Parameters such as hematocrit value , ovarian size, the number of follicles in the ovary, endometrial capillary congestion and thickness values were evaluated and compared. Results: As a result, in our study, it was seen that ondansetron was effective on OHSS in many parameters. It is thought to be as effective as cabergoline. When we look at the literature, this is the first study in which ondansetron was evaluated for this purpose. It would be good to show this effect of ondansetron with other studies.

Effectivity of Pancreatic Enzyme Replacement Therapy in Malnourished Children.

OBJECTIVE: Malnutrition is commonly seen in children with exocrine pancreatic insufficiency (EPI). Pancreatic enzyme replacement therapy (PERT) is the mainstay treatment of acute malnutrition in children detected with a disease closely associated with EPI (eg, cystic fibrosis). The effectiveness of PERT in children with malnutrition without any chronic disease, however, remains unclear. The aim of this study was to investigate the effectiveness of PERT on weight gain and EPI in children classified as moderately and severely malnourished according to the World Health Organization (WHO) classification. MATERIALS AND METHODS: The study included a total of 40 children aged 2-16 years who were classified as moderately and severely malnourished according to the WHO classification. The patients were randomly divided into 2 groups: PERT group (n = 20) received 2000 U lipase/kg/day (in 4 doses) in addition to hypercaloric enteral supplements and control group received hypercaloric enteral supplements only. In both groups, anthropometric measurements and the assessment of fecal elastase-1 (FE-1) levels were performed both at first admission and at the end of the 8-week treatment period. RESULTS: On the basis of WHO classification, 10 (25%) children were classified as severely malnourished and 30 (75%) children as moderately malnourished. EPI was detected in all the patients, among whom 24 (60%) patients had severe EPI. At the end of the treatment, body weight, height, and body mass index (BMI) increased significantly in both groups compared to their pre-treatment values, whereas no significant difference was found with regard to waist circumference (WC) and FE-1 levels. Similarly, no significant difference was found between pre- and posttreatment measurements of PERT and control groups (P > 0.05) and between pre- and posttreatment measurements of patients with moderate and severe malnutrition (P > 0.05). CONCLUSIONS: Malnutrition remains a serious public health problem, and thus, the development of novel treatment methods is highly essential. PERT is one of the most commonly considered alternatives, although there is little documentation of PERT in the literature. In the present study, although PERT resulted in higher weight gain, it established no significant difference between the 2 groups.

Typhoid Fever Accompanied With Hematopoetic Lymphohistiocytosis and Rhabdomyolysis in a Refugee Child.

Typhoid fever is an acute and systemic infectious disease that is specific to humans and is caused by Salmonella typhi. Patients may present with different findings ranging from simple fever to multiple organ failure. Hemophagocytosis and rhabdomyolysis are rare complications of typhoid fever. In this study, we presented a case of hemophagocytic lymphohistiocytosis and rhabdomyolysis in a 14-year-old girl who migrated from Mosul, Iraq, 1 month ago.

Congenital Neutropenia Patient With Hypomorphic Biallelic CSF3R Mutation Responding to GCSF.

Congenital neutropenia (CN) is a rare disorder, and the most common gene responsible for CN is ELANE. Furthermore, the mutations of HAX1, G6PC3, and JAGN1 genes may cause CN. These patients generally find great benefit from subcutaneous administration of Granulocyte Colony Stimulating Factor (GCSF). In recent years, Biallelic Colony Stimulating Factor 3 Receptor (CSF3R) mutations have been described as an underlying defect of CN in several children. In contrast to the previous group, the patients who have a CSF3R mutation do not respond to GCSF treatment. Here, we present a CN patient with hypomorphic biallelic CSF3R mutation responding to GCSF.

What is the protective effect of krill oil on rat ovary against ischemia-reperfusion injury?

AIM: In this study, we aimed to investigate the protective effect of krill oil (KO) against ischemia-reperfusion (I/R) injury on rat ovary. METHODS: This study was conducted with 32 Wistar Albino rats. Rats were divided into four groups, with eight rats in each group-as follows: Sham group, I/R group, I/R + low dose KO group (50 mg) and I/R + high dose KO group (500 mg). The histopathological and follicle counts were performed on the right ovary. The total antioxidant status, total oxidant status and oxidative stress index were evaluated on the left ovary. And also serum N-thiol level, serum T-thiol level, serum disulfide (SDS) level, serum disulfide/N-thiol and serum disulfide/T-thiol ratios were evaluated too. RESULTS: A statistically significant difference was determined between the I/R group and all the other groups for all parameters. There was significant difference between KO groups and the Sham group for the parameters of serum N-thiol, serum T-thiol, SDS, serum disulfide/N-thiol and serum disulfide/T-thiol. SDS, total oxidant status and oxidative stress index were determined to be the highest in the I/R group and the lowest in the low dose KO group. The total antioxidant status values were found to be the highest in the high dose KO group and the lowest in the I/R group. Follicle counts and histological injury scores showed no significant difference between Sham and KO groups. CONCLUSION: This study demonstrated that KO has beneficial effects on decreasing the injury after I/R on rat ovary.

Ultrasonographic and histopathological investigation of the effect of N-acetylcysteine on doxorubicin-induced ovarian and uterine toxicity in rats.

BACKGROUND: This study aimed to investigate the mitigating effect of N-acetylcysteine (NAC) on doxorubicin (DOX)-induced ovarian and uterine toxicity in rats using laboratory tests, ultrasonographic (US) imaging, and histopathology analysis. METHODS: Forty-eight rats were divided into six groups (n = 8) as follows: Group A (control) (0.5 mL saline administered intraperitoneally [IP]), Group B (a single 10 mg/kg dose of DOX administered IP on day 1), Group C (a single 10 mg/kg dose of DOX administered IP 24 h before sacrifice), Group D (100 mg/kg of NAC administered IP for 21 days), Group E ( a single 10 mg/kg dose of DOX administered IP on day 1 and 100 mg/kg of NAC administered IP for 21 days), and Group F (100 mg/kg of NAC administered IP for 21 days and a single 10 mg/kg dose of DOX administered IP 24 h before sacrifice). The ovaries were examined using B-mode US on days 1, 14, and 21, and the histopathological examinations of the ovaries and the uterus were undertaken after sacrifice on day 22. RESULTS: Histomorphological analyses showed that ovarian weight decreased after DOX administration in Group B but not in Group E. US revealed a transient increase in ovarian size in Group B and E, reverting to baseline levels over time, as well as a progressive increase in peritoneal fluid in Groups B and E. Group B exhibited a significant decrease in the thickness of the endometrium and myometrium and uterine cornual length, which was not observed in Group E. Histopathological examination showed that DOX caused a decline in follicular count, especially in primordial, secondary, and Graafian follicles, and resulted in follicular atresia, predominantly in Group B. Destructive degeneration/necrosis and vascular changes were most prominently seen in the corpus luteum of Groups C and B. In NAC-treated rats (Groups E and F), although germ cell damage was present, atretic follicles and vascular changes, such as hyperemia and congestion, were reduced. The anti-müllerian hormone (AMH) level was the highest in Group F. CONCLUSIONS: NAC, an antioxidant, attenuated DOX-induced gonadotoxicity in rats.

Effects of edaravone on testicular torsion-detorsion injury in rats.

BACKGROUND AND OBJECTIVE: This study aimed to assess the protective ability of edaravone on testicular torsion-detorsion injury in rats. METHODS: Eighteen adult male Sprague-Dawley rats were randomly divided into three groups: Sham group (control, n = 6); testicular torsion/detorsion (T/D group, n = 6) and T/D+edaravone (T/D+E group, n = 6). The spermatic cords of rats of the T/D group and the T/D+E group were rotated 720° in a clockwise direction and maintained for 120 min in this torsion position. Around 90 min after the torsion, edaravone at a dose of 10 mg/kg dissolved in saline was administered IP to the T/D+E group. The testicle was counter-rotated to its normal position to allow reperfusion for 4 h. Left testes of each animal were excised 240 min after beginning of reperfusion. Oxidative stress markers (TAS, TOS, SOD, and MDA) and apoptotic pathways (Caspase 3, Caspase 8, Caspase 9, Bcl-2, and Bax,) were assessed by ELISA methods. Also, testicles were subjected to the histopathologic and ultrasound examinations. RESULTS: Ultrasound imaging showed that edaravone reduced the surface area and increased vascularization in testicles with T/D (p < 0.0001, p < 0.05, respectively). Edaravone pretreatment markedly decreased the levels of MDA, TOS, Bcl-2, Bax, Caspase 3, Caspase 8, and Caspase 9 (p < 0.0001). Also, it increased significantly TAS levels (p < 0.0001) and reduced insignificantly SOD activity. Histopathologic examinations demonstrated that edaravone significantly attenuated the histological damage caused by T/D in testicles. CONCLUSION: Taken together, the findings indicate that pretreatment of edaravone has protective effect against testicular T/D injury.

Perceived usefulness of data entry tools in medical encounters: a survey.

Electronic Health Records allows direct data entry and is an important factor for accurate diagnosis. However, two drawbacks of this system is the time needed to create them, which can reduce health care professional productivity, and the fact that it is error prone. It is important, therefore, to select the most appropriate methods and tools for data entry by the health care providers at the point of care in order to minimize a loss of productivity. The study aims to understand health care professionals' perceptions of the data entry process, and determine the appropriate methods, tools and functions that would facilitate the process, minimize loss of productivity and improve quality. A questionnaire which consisting of 18 basic questions (including demographic data) was posted on a web site which hosts questionnaires, on an established online community space and also mailed to health care professionals who are working in various hospitals for a duration of 10 months. Totally, 533 medical care professionals who are primarily from Turkey participated in the survey, of which 284 were medical doctors, 127 were nurses and the rest, other medical professionals. While the clear majority of participants involved in data entry use keyboard and mouse, most expressed a preference for more convenient methods, such as voice recognition or touch screen. Furthermore, physicians reported rarely spending more than 15 min for each consultation and conducting 21-30 examinations a day. The main motivation for creating an efficient direct data entry is to increase time allowed for patient examination, and to improve accuracy of diagnosis. Despite a heavy workload, health care professionals are very receptive to the idea of using a convenient data entry tool and keeping electronic patient records. Emergent data entry technologies in health sector can improve the quality of examinations, physicians' productivity and can decrease the percentage of medical misdiagnosis.

Mercury toxicity: a family case report.

BACKGROUND: Environmental pollution exposes humans to toxic substances. Herein we present 5 family members aged20-54 years that were poisoned by liquid mercury. CASE REPORTS: Case 1 presented to our clinic with cough, fever, and night sweats. The patient had neutropenia, anemia,and pneumonia, rapidly developed acute respiratory distress syndrome (ARDS), and died on day 4 of hospitalization.Her WBC count was 0.4 × 10³ mm-3 (normal range: 4.3-10.3 × 103 mm-3) and Hb was 10.8 g dL-1 (normal range: 11.5-16.0 g dL-1). Case 2 presented with bicytopenia; the leukocyte count was 1.3 × 103 mm-3 (normal range: 4.3-10.3 × 103mm-3) and the PLT count was 88 × 103 mm-3 (normal range: 150-400 × 103 mm-3). Cases 2 and 3 had toxic peripheralneuropathy. The PLT count in case 3 was 123 × 103 mm-3 (normal range: 150-400 × 103 mm-3). Cases 4 and 5 presentedwith fatigue and headache; these 2 patients did not have positive findings, apart from high levels of mercury in theblood. We have written informed consent. CONCLUSION: We think that heavy metal exposure-although rare-should be considered in patients that present withnumerous symptoms involving multiple systems, including the cardiovascular, respiratory, and neurological systems.The present report is unique in that in describes mercury poisoning in 5 members of the same family.

Comparison of the healing effects of mesazaline and Ganoderma lucidum in acetic acid-induced colitis in rats.

PURPOSE: The etiology and pathogenesis of distal colitis (DC) are poorly understood. Activation of intestinal inflammatory response may lead to intestinal tissue necrosis. Antioxidant and anti-inflammatory agents are among the treatment options. Our study aimed to compare the protective effects of mesalazine and Ganoderma lucidum in acetic acid (AA)-induced colitis in rats. METHODS: Twenty-four rats were randomly grouped as colitis, mesalazine, G. lucidum, and combined (G. lucidum + mesalazine) groups. DC was induced by intrarectal administration of AA. Statistical comparisons were done by using parameters including colonic tissue IL-1, IL-6, TNF-α, and CRP levels. Histopathologic changes of the samples of colonic tissue were scored as mucosal damage score and inflammatory score. A P-value of <0.05 was considered significant. RESULTS: Intrarectal administration of AA leads to increased interleukin and CRP levels. High mucosal damage and inflammatory scores were noted in colitis group animals. Single mesalazine or G. lucidum treatment produced considerably decreased tissue interleukin and CRP levels. The lowest tissue interleukin and CRP levels were noted in the combined treatment group of animals. Mucosal damage and inflammatory scores were found to be significantly low in this group of animals. CONCLUSION: The intrarectal administration of AA results in an activation of intestinal inflammation and severe mucosal damage in colonic tissue. Single use of mesalazine and G. lucidum treatment decreases the severity of intestinal inflammatory response and mucosal damage. The healing effects of the combined treatment of mesalazine and G. lucidum seem to be more effective than that of separate use in the treatment of DC.

Investigation of Thiol/Disulfide Balance in Obese Rats with Non-Alcoholic Fatty Liver Disease.

PURPOSE: Due to the increasing prevalence of obesity worldwide, non-alcoholic fatty liver disease (NAFLD) has reached epidemic dimensions over time. NAFLD is the most common cause of childhood chronic liver disease. There is a relationship between NAFLD and oxidative stress. This study aims to investigate the changes in thiol/disulfide homeostasis parameters to determine the oxidant/antioxidant balance in obese rats with diet-induced NAFLD and healthy rats. METHODS: Twelve Wistar albino rats were used in this study. Experimentally produced NAFLD obese rats (n=6) and healthy rats were compared. Experimental NAFLD model was created with a special fatty liver diet (Altromin® C1063, Fatty Liver Diet, Exclusivet, Lage, Germany). The biochemical and histopathological features of the groups, as well as serum thiol/disulfide homeostasis parameters, were analyzed and compared. RESULTS: In the experimentally induced NAFLD rat model, they gained more weight than the control group. Steatosis (at least grade 2) occurred in all rats fed with special fatty liver diet for 12 weeks. Histopathologically, no high-grade inflammation was observed in rats with experimental NAFLD after feeding a diet for 12 weeks. Results revealed that aspartate transaminase and alanine transaminase levels were high, albumin levels were low, oxidant stress parameters increased, and antioxidant thiol groups decreased. CONCLUSION: Experimental NAFLD is characterized by increased oxidant stress accompanying fatty tissue in the liver. Analysis of thiol/disulfide homeostasis parameters in NAFLD can be used in further studies to develop effective treatment options.

Early forest fire detection using radio-acoustic sounding system.

Automated early fire detection systems have recently received a significant amount of attention due to their importance in protecting the global environment. Some emergent technologies such as ground-based, satellite-based remote sensing and distributed sensor networks systems have been used to detect forest fires in the early stages. In this study, a radio-acoustic sounding system with fine space and time resolution capabilities for continuous monitoring and early detection of forest fires is proposed. Simulations show that remote thermal mapping of a particular forest region by the proposed system could be a potential solution to the problem of early detection of forest fires.

Detection of Hidden Hostile/Terrorist Groups in Harsh Territories by Using Animals as Mobile Biological Sensors.

Terrorism is the greatest threat to national security and cannot be defeated by conventional military force alone. In critical areas such as Iraq, Afghanistan and Turkey, regular forces cannot reach these hostile/terrorist groups, the instigators of terrorism. These groups have a clear understanding of the relative ineffectiveness of counter-guerrilla operations and rely on guerrilla warfare to avoid major combat as their primary means of continuing the conflict with the governmental structures. In Internal Security Operations, detection of terrorist and hostile groups in their hiding places such as caves, lairs, etc. can only be achieved by professionally trained people such as Special Forces or intelligence units with the necessary experience and tools suitable for collecting accurate information in these often harsh, rugged and mountainous countries. To assist these forces, commercial micro-sensors with wireless interfaces could be utilized to study and monitor a variety of phenomena and environments from a certain distance for military purposes. In order to locate hidden terrorist groups and enable more effective use of conventional military resources, this paper proposes an active remote sensing model implanted into animals capable of living in these environments. By using these mobile sensor devices, improving communications for data transfer from the source, and developing better ways to monitor and detect threats, terrorist ability to carry out attacks can be severely disrupted.

Animals as Mobile Biological Sensors for Forest Fire Detection.

This paper proposes a mobile biological sensor system that can assist in earlydetection of forest fires one of the most dreaded natural disasters on the earth. The main ideapresented in this paper is to utilize animals with sensors as Mobile Biological Sensors(MBS). The devices used in this system are animals which are native animals living inforests, sensors (thermo and radiation sensors with GPS features) that measure thetemperature and transmit the location of the MBS, access points for wireless communicationand a central computer system which classifies of animal actions. The system offers twodifferent methods, firstly: access points continuously receive data about animals' locationusing GPS at certain time intervals and the gathered data is then classified and checked tosee if there is a sudden movement (panic) of the animal groups: this method is called animalbehavior classification (ABC). The second method can be defined as thermal detection(TD): the access points get the temperature values from the MBS devices and send the datato a central computer to check for instant changes in the temperatures. This system may beused for many purposes other than fire detection, namely animal tracking, poachingprevention and detecting instantaneous animal death.

Erythrocyte membrane glycation and NA(+)-K(+) levels in NIDDM.

Although there are many investigations on protein glycation in diabetic patients, many detailed studies are needed on this subject. In this study, the correlation between red cell membrane and serum protein glycation was investigated in NIDDM. The relation of membrane glycation to intracellular Na(+) and K(+) levels was also considered. Forty patients with NIDDM and 22 healthy subjects were included in the study. The membrane proteins were isolated, and total protein (TP(m)) and fructosamine (FA(m)) levels were determined. Serum glucose, fructosamine (FA(s)) and total protein (TP(s)) levels were also measured. HbA(1C), red blood cell (RBC) and reticulocyte (RET) counts in whole blood were made in all samples. NA(+) and K(+) levels of both serum and RBC were determined. The patient group had lower levels of K(+)(RBC) (P<.001) and Na(+)(s) (P<.05) and RBC count (P<.05), and higher levels of FA(m) (P<.001), Na(+)(RBC) (P<.01), K(+)(s) (P<.01), glucose (P<.001) and HbA(1C) (P<.001) than those of controls. The ratios of FA(s)/TP(s) (P<.001) and FA(m)/TP(m) (P<.001) were higher in patients than in control. As a result, HbA(1C) levels and the ratio of FA(m)/TP(m) were high in NIDDM patients (P<.001) and these patients have slight negative correlations in FA(m)/TP(m) and FA(s)/TP(s) (P<.05). On the other hand, that there is no correlation between RBC membrane protein glycation and RBC Na(+) and K(+) levels may be caused by the fact that the membrane protein glycation is lower than that of other soluble proteins and that the membrane proteins are functional with respect to Na(+)-K(+) transport.

MEDWISE: an innovative public health information system infrastructure.

In this paper, we present MedWise, a high level design of a medical information infrastructure, and its architecture. The proposed system offers a comprehensive, modular, robust and extensible infrastructure to be used in public health care systems. The system gathers reliable and evidence based health data, which it then classifies, interprets and stores into a particular database. It creates a healthcare ecosystem that aids the medical community by providing for less error prone diagnoses and treatment of diseases. This system will be standards-compliant; therefore it would be complementary to the existing healthcare and clinical information systems. The key objective of the proposed system is to provide as much medical historical and miscellaneous data as possible about the patients with minimal consultation, thus allowing physicians to easily access Patients' Ancillary Data (PAD) such as hereditary, residential, travel, custom, meteorological, biographical and demographical data before the consultation. In addition, the system can help to diminish problems and misdiagnosis situations caused by language barriers-disorders and misinformation. MedWise can assist physicians to shorten time for diagnosis and consultations, therefore dramatically improving quality and quantity of the physical examinations of patients. Furthermore, since it intends to supply a significant amount of data, it may be used to improve skills of students in medical education.

Effects of valproate, carbamazepine, and levetiracetam on the antioxidant and oxidant systems in epileptic patients and their clinical importance.

PURPOSE: This study was carried out to determine the effects of valproate (VPA), carbamazepine, and levetiracetam (LEV) on antioxidant and oxidant enzyme activities and the clinical importance of these effects. METHODS: We enrolled 32 patients receiving VPA, 17 receiving carbamazepine, 8 receiving LEV, 11 on multidrug therapy, and 30 sex- and age-matched healthy volunteers. We measured the serum activities of paraoxonase and arylesterase and the levels of 8-hydroxyguanine (8-OHG) and oxidized low-density lipoprotein in all the subjects. We also determined the clinical features of the patients. RESULTS: The serum paraoxonase and arylesterase activities were significantly lower (P = 0.003 and P = 0.0001, respectively), and the oxidized low-density lipoprotein and 8-OHG levels were higher (P = 0.029 and P = 0.0001, respectively) in the patients than in the controls. The serum antioxidant activity was low, and the oxidant activity was high in the monotherapy patients (P < 0.05). Comparing the monotherapy with the polytherapy, only the combination of VPA-LEV was associated with a high 8-OHG level (P = 0.04). The serum 8-OHG level was higher in the patients taking antiepileptic drugs (AEDs) for the first 2 months than in the controls (P = 0.0001) and positively correlated with the duration of epilepsy (r = 0.387, P < 0.01). CONCLUSIONS: Oxidative stress is seen in each of the AEDs after the first 2 months. There was no dominance of the monotherapy over the polytherapy, except for the VPA-LEV combination. None of the patients' characteristic features were related to oxidative damage, except for the duration of the epilepsy and the AED therapy.

The effect of adrenalectomy on leptin levels and some metabolic parameters in rats with diet-induced obesity.

Recently, there has been many investigations on the relationship between leptin and obesity, which is the main health problem in developed countries. In some reports, it has been claimed that the adrenalectomy has lead to weight loss and thus prevented obesity induced in rodents in various ways. It has also been accepted that diet-induced obesity in animals is very similar to obesity in humans beings. In this study, obesity has been developed with high-calorie diet given for 8 weeks in Sprague-Dawley rats. Then, it has been investigated how leptin and some metabolic parameters change in blood samples obtained from rats 15 d after adrenalectomy. Leptin levels was determined with Radio Immun Assay (RIA, Linco Research Co) method. Our study showed that, there were statistically significant increases in leptin (p<0.001), glucose (p<0.05), triglyceride (p<0.01) levels in diet-induced obese rats (n=19) when compared with the findings of control rats, lean ones (n=16), (Tables 3, 4). Adrenalectomy led to decreased serum leptin (p<0.001) and triglyceride (p<0.01) levels both in the obese and lean rats (Table 5). As a conclusion, it could be claimed that the decrease in leptin levels may be attributed to reduced adipose tissue due to adrenalectomy. On the other hand, the decreases in glucose and triglyceride levels might be the consequence of reduced lipogenesis and impaired gluconeogenesis with the effect of adrenalectomy. It was concluded that adrenalectomy might prevent obesity by affecting leptin and intermediate metabolism.

Melatonin reduces lipid peroxidation and nitric oxide during irradiation-induced oxidative injury in the rat liver.

Radiation therapy is a popular and useful tool in the treatment of cancer. Melatonin participates in the regulation of a number of important physiological and pathological processes. Melatonin, a powerful endogenous antioxidant, plays a role in the reduction of oxidative damage. Thirty adult rats were divided into five equal groups. On the day of the experiment, groups I and II were injected with 5 or 10 mg/kg melatonin, respectively, while group III received isotonic NaCl solution. Thirty minutes later, groups I, II and III were exposed to 6.0 Gy whole body ionizing radiation in a single fraction. Group IV was injected with 5 mg/kg melatonin but was not irradiated. The final group was reserved as sham treated. Liver malondialdehyde (MDA) and nitric oxide (NO*) levels were measured in all groups. Whole body irradiation caused a significant increase in liver MDA and NO* levels. Hepatic MDA and NO* levels in irradiated rats that were pretreated with melatonin (5 or 10 mg/kg) were significantly decreased. Malondialdehyde and NO* levels were reduced in a dose-related manner by melatonin. The data show that melatonin reduces liver damage inflicted by irradiation when given prior to the exposure to ionizing radiation. The radioprotective effect of melatonin is likely achieved by its ability to function as a scavenger for free radicals generated by ionizing radiation.