Study of Stress Level Among Medical School Students of Semnan University, Iran

Background:

The professional education can be stressful experience and medical students are exposed to high levels of stress in both theoretical and clinical components of their educational programme. The high level of stress often leads to disruptions in physiological and psychological health.

Objective:

The purpose of this study was to study stress in medical school students of Semnan university.

Methods:

This study was a descriptive and cross-sectional research. The sample were 211 students of general physicians (160) and paramedical (51). 206 students filled in a questionnaire.Data were collected using a stress questionnaire (R.S.Eliot). Then data were analyzed by SPSS and mean, frequency distributions. For this study were used chi-square, spearman and pearson correlation coefficient.

Results:

The findings showed 9.7% of students under study had high control degree, 82.5% of students had intact life but sometimes stressful situation caused anxiety for them, 6.8% of students feel depress and 1% in their life have mental crisis or conflict.

Conclusion:

Teaching to students in order to reduce stress level and provide educational improvement in medical students are recommended.

The Influence of Brass Compensator Thickness and Field Size on Neutron Contamination Spectrum in 18MV Elekta SL 75/25 Medical Linear Accelerator with and without Flattening Filter: A Monte Carlo Study

BACKGROUND

One of the most significant Intensity Modulated Radiation Therapy treatment benefits is a high target to normal tissue dose ratio. To improve this advantage, an additional accessory such as a compensator is used to deliver doses. Compensator-based IMRT treatment is usually operated with an energy higher than 10 MV. Photoneutrons, which have high linear energy transfer and radiobiological effectiveness, are produced by colliding high-energy photon beams with linear accelerator structures, then they deliver the unwanted doses to patients and staff. Therefore, the neutron energy spectra should be determined in order to calculate and reduce the photoneutron risk.

OBJECTIVE

We have conducted a comprehensive and precise study on the influence of brass compensator thickness and field size on neutron contamination spectrum in an Elekta SL 75/25 medical linear accelerator with and without the flattening filter by Monte Carlo method.

MATERIAL AND METHODS

MCNPX MC Code version 2.6.0 was utilized to simulate the detailed geometry of Elekta SL 75/25 head components based on Linac's manual. This code includes an important feature to simulate the photo-neutron interactions. Photoneutrons spectrum was calculated after the Linac output benchmarking based on tuning the primary electron beam.

RESULTS AND CONCLUSION

Based on the Friedman and Wilcoxon nonparametric tests results (P<0.05), photoneutron fluence directly depends on the field size and compensator thickness. Moreover, the unflattened beam provides lower photoneutron fluence than the flattened beam. Photoneutrons fluence is not negligible in compensator-based IMRT treatment. However, in order to optimize treatment plans, this additional and unwanted dose must be accounted for patientss.

The effects of garlic-supplemented diets on skin mucosal immune responses, stress resistance and growth performance of the Caspian roach (Rutilus rutilus) fry

This study was conducted to evaluate the effects of garlic supplementation on some skin mucus immune parameters, mucus antimicrobial activity and growth performance of the Caspian roach (Rutilus rutilus caspicus) fry. Fish (1 ± 0.07 g) were divided into four groups fed diets containing 0 (control), 5, 10 and 15 g kg(-1) garlic for 8 weeks. The results showed that there was a significant increase in weight gain and specific growth rate in those fish fed garlic diets compared with the control (P < 0.05). Condition factor was not significantly affected by garlic dosage. At the end of trial, the epidermal mucus protein level, alkaline phosphatase and antimicrobial activity against 2 g-negative bacteria (Escherichia coli and Serratia marcescens) and gram-positive bacteria (Streptococcus faecium and Micrococcus luteus) were measured. Skin mucus alkaline phosphatase, protein levels and antimicrobial activity were increased following garlic administration, and the bacterial growth inhibition zones were significantly elevated in garlic-fed fish (P < 0.05). In salinity stress experiment, no differences were observed for survival rate among the experimental diets. No mortality was recorded during the feeding trial. These results indicated that dietary garlic beneficially affects the skin mucus immune parameters and growth performance of the Caspian roach fry.

Prognostic role of Helicobacter pylori infection in acute coronary syndrome: a prospective cohort study

Abstract

In a prospective cohort study, we evaluated the effect of Helicobacter pylori seropositivity on the risk of future adverse cardiovascular outcomes among patients with acute coronary syndrome (ACS). In 433 patients, IgA and IgG antibodies to H pylori, along with classic risk factors, including hypertension, diabetes, hyperlipidaemia, smoking and family history of coronary artery disease (CAD) were determined. Short-and long-term follow-up information on adverse outcomes, defined as recurrence of unstable angina, myocardial infarction, coronary angioplasty, coronary artery bypass graft surgery, and sudden cardiac death was obtained. None of the classic CAD risk factors correlated with incidence of either short- or long-term outcomes. Seropositivity for H pylori was significantly associated with risk of short-term adverse outcomes, and independently predicted their incidence in multivariate regression (R = 3.05, p < 0.001). Results failed to show such an association between H pylori seropositivity and long-term adverse outcomes. H pylori infection may affect short-term prognosis in patients with ACS. Randomised trials are needed to evaluate the role of H pylori eradication in these patients.

Compensatory growth in juvenile roach Rutilus caspicus: effect of starvation and re-feeding on growth and digestive surface area

The aim of this study was to investigate compensatory growth in juvenile Rutilus caspicus during starvation and re-feeding periods. The results confirmed the existence of compensatory growth in R. caspicus which depended on the duration of food deprivation. Complete compensatory growth occurred in the fish that were food deprived for at least 3 weeks. Starvation and re-feeding had no significant effect on the digestive somatic index and intestinal surface areas in the fish that were food deprived for 1 week, while they showed a significant decrease and increase, during starvation and re-feeding in the fish that were food deprived for 2 and 3 weeks. This knowledge may have application in aquaculture, as appropriate exploitation of compensatory growth can give increased growth rate and feeding efficiency.

Relationship between disease activity and serum levels of vitamin D and parathyroid hormone in rheumatoid arthritis

OBJECTIVE

Measuring vitamin D and its regulating hormones in the serum might be an accurate method for assessment of rheumatoid arthritis (RA) activity. We tested the hypothesis that the serum levels of vitamin D and parathyroid hormone (PTH) are associated with the grade of disease activity in an unselected cohort of patients with RA.

METHODS

A total of 158 patients who met the American College of Rheumatology criteria for RA were examined and categorized as the patients with the active RA (n = 87) and silent RA (n = 71). Blood samples were obtained after at least eight-hour overnight fasting and the levels of 25-OH-vitamin D and PTH were measured.

RESULTS

The levels of the vitamin D in patients with active RA were significantly lower than in those with silent RA (49.38±38.21 versus 64.64±43.61 nmol/l; p = 0.022). The PTH serum level lower than the normal range (< 0.8 nmol/l) was statistically observed similar in the active RA group compared with another ones (10.3 % versus 4.2 %, p = 0.149). Serum levels of vitamin D and PTH were not influenced by patients' gender and age as well as the duration of disease.

CONCLUSION

Serum level of vitamin D was inversely related to RA activity and this relationship might be independent of PTH secretion or activity.

Effects of gradual salinity increase on osmoregulation in Caspian roach Rutilus caspicus

This study was carried out to determine the effects of gradual salinity increase on osmoregulatory ability of the Caspian roach Rutilus caspicus, under conditions which mimic stocking conditions of hatchery-raised fish. Initially, 30 juvenile fish (mean ± S.D. 3.20 ± 0.34 g) were transferred to 20 l circular tanks, in which salinities were changed in a stepwise fashion, from 0 to 5, 10 or 15 at 48 h intervals. The fish at salinity 15 were held for an additional 48 h at this salinity. Forty-eight hours after salinity transfer, survival rate, haematocrit, plasma Cl(-) , Na(+) and K(+) concentrations, osmolality and gill Na(+) /K(+) -ATPase (NKA) activity were measured. The only effect of exposure to 5 was a significant reduction in haematocrit compared to the freshwater control group. Exposure to salinity 10 raised haematocrit, Cl(-) and Na(+) concentrations and osmolality. At 48 h exposure to salinity 15, haematocrit, Cl(-) and Na(+) concentrations and osmolality were significantly higher than freshwater controls, and gill NKA activity was significantly lower, but the effect on NKA was no longer evident at 96 h exposure. There were no effects on survival. These results indicate that R. caspicus juveniles experience an initial non-lethal iono-osmotic perturbation following salinity increase but can adapt to brackish water at salinity 15.

Comparing psychological disorders between two wards of internal medicine and A&E (2005 —2006)

Introduction

One of the important problems of patient in internal medicine is less attention to emotional and psychological issues. The method of treatment would change when the patients have psychological problem.

Objectives

The comparing of prevalence of mental disorders in internal medicine patients with parallel groups of A&E's patients.

Aims

The evaluation of prevalence of psychological problem in internal ward and A&E.

Methods

Three hundred patients have been checked in internal and emergency wards. They have chosen by a Purposive accessible sampling method. The psychopathological profile was assessed using the SCL-90 questionnaire by Iranian version. Data have been computed and analyzed by SPSS V.17 and Student t test for parametric variables and Mann-Whitney for the analysis of nonparametric variables and linear regression have been used to identify the impact of independent variables. The results have been considered significant when the two tailed p-value was less than 0.05.

Results

Physical disorder was the main complain of internal ward (76.7%) and A&E (53.3%) patients. The main important complain of women patients in A&E were paranoid (64.3%) and in the men were physical problem (53%).

In 50 or older, the main complain in internal ward was psychiatric problem (%80.6), and in the emergency units obsessive- compulsive were %50.

Conclusions

Prevalence of nine psychiatric disorders in internal ward patients was significantly higher more than A&E patients. Most of patient that accepted in internal ward had psychiatric problem. Therefore, it’s necessary to pay attention to this kind of disorders for early treatment of patients.

The role of religiosity, coping strategies, self-efficacy and personality dimensions in the prediction of Iranian undergraduate rehabilitation interns' satisfaction with their clinical experience

OBJECTIVE

to investigate the relationship between religiosity, coping styles, self-efficacy and personality dimensions as predictors of satisfaction with clinical experience in rehabilitation interns during transition from academic study to clinical internship.

DESIGN

a cross-sectional survey design.

SETTING

five rehabilitation faculties.

PARTICIPANTS

three hundred and eighteen undergraduate rehabilitation interns, including physical therapy, occupational therapy and speech and language pathology students.

MAIN OUTCOME MEASURES

Islamic Religiosity Scale, Ways of Coping Questionnaire, General Self-efficacy Scale, NEO Five Factor Inventory, and Satisfaction with Clinical Experiences Questionnaire.

RESULTS

religiosity, problem-focused coping and general self-efficacy had significant positive correlation with satisfaction with clinical internship in rehabilitation students. Among personality dimensions, openness, agreement and consciousness had significant positive correlation with satisfaction with clinical experience and neuroticism had significant negative correlation with satisfaction with clinical experience. The results of regression analysis demonstrated that religiosity and self-efficacy had important roles in the prediction of satisfaction with clinical experience in all the rehabilitation intern students of three disciplines (physical therapy, occupational therapy, and speech and language pathology).

CONCLUSION

religiosity, problem-focused coping and general self-efficacy seem to be good predictors of satisfaction with clinical internship in rehabilitation students.

Effect of metoclopramide on nosocomial pneumonia in patients with nasogastric feeding in the intensive care unit

This study in the Islamic Republic of Iran aimed to determine whether metoclopramide can prevent nosocomial pneumonia in the intensive care unit (ICU). Of 220 patients admitted to the surgical ICU who had a nasogastric tube for more than 24 hours, 68 case patients received oral metoclopramide (10 mg every 8 hours) and 152 control patients did not. Similar proportions of cases and controls developed nosocomial pneumonia (33.8% versus 33.6%). Endotracheal intubation was a risk factor for nosocomial pneumonia (odds ratio 7.70). There were no significant differences between groups in mortality rate or time of onset of nosocomial pneumonia. Metoclopramide appears to have no effect on the development of nosocomial pneumonia with nasogastric feeding.

Obesity in the Iranian population

There is an obesity epidemic worldwide, which has been increasing in recent years. An epidemiologic cross-sectional study was conducted among 3799 persons who were 30-70 years old in Semnan Province, Iran. Multistage cluster sampling was performed, and subjects were selected from urban and rural populations. Body weight, height and waist circumference (WC) were measured, and body mass index (BMI) and waist to hip ratio (WHR) were calculated. Overweight and obesity were defined as 25 < or = BMI < 30 and > or =30 respectively in men with WHR > or = 0.9 or WC > or = 102 cm, and women with WHR > or = 0.8 or WC > or = 88 cm were considered centrally obesite. Prevalence of obesity and overweight was 26.3% and 40.6% respectively. Prevalence of obesity was more among women (39.5%) than men (14.5%) with central obesity prevalence using WHR and WC cut-points of 72.2% and 26.6% respectively. There was a significant association between obesity and age, gender, residential area and educational level (P < 0.01). In conclusion, prevalence of obesity and overweight among 30-70 years old, especially among women, was higher than expected. A comprehensive educational programme on obesity risk factors and obesity-related diseases is necessary.

Endocrinopathies in patients with transfusion-dependent beta-thalassemia

Thalassemia is common in Iran. Appropriate therapy for this disease includes a regular blood transfusion and chelation therapy. However, in this approach patients will inevitably experience side effects, particularly iron overloads in critical organs, including heart, ductless glands, and liver. This study attempted to determine prevalence of adenoidal abnormality between Iranian thalassemia patients for prediagnosis and to offer necessary medical measures. This is a descriptive nonrandomized study and included all the patients suffering from thalassemia major referring to medical centers linked with the Iranian blood transfusion organization from January 2004 to January 2005. All patients were sampled for CBC, FBS, 2-h BS, HbAlC, liver function, renal function, and endocrine disease. Initially, reports of adenoidal experiments as well as other associated parameters were provided from medical records. A total of 437 patients enrolled in the study: 5.4% suffered from diabetes, 1% had hypothyroid, and 1 person showed hypoparathyroidism. The mean levels of ferritin in diabetic and nondiabetic groups and hypothyroid and nonhypothyroid groups were not significantly different. The mean levels of ferritin among various age groups also were not significantly different. Results of a comparison between present research and similar studies conducted throughout Iran and those performed abroad on adenoidal abnormalities in thalassemia patients show that subject patients of this study statistically suffered from fewer difficulties than diabetes patients in other studies.

Peripheral intravenous catheter-related phlebitis and related risk factors

INTRODUCTION

Peripheral intravenous catheter-related phlebitis is a common and significant problem in clinical practice. This study aims to investigate the incidence of phlebitis and to evaluate some important related factors.

METHODS

300 patients admitted to medical and surgical wards of hospitals in Semnan, Iran from April 2003 to February 2004 were prospectively studied. Variables evaluated were age, gender, site and size of catheter, type of insertion and underlying conditions (diabetes mellitus, trauma, infectious disease and burns). Phlebitis was defined when at least four criteria were fulfilled (erythema, pain, tenderness, warmth, induration, palpable cord and swelling). Any patient who was discharged or their catheter removed before three days were excluded.

RESULTS

Phlebitis occurred in 26 percent (95 percent confidence interval [CI] 21- 31 percent) of patients. There was no significant relationship between age, catheter bore size, trauma and phlebitis. Related risk factors were gender (odds-ratio [OR] 1.50, 95 percent CI 1.01-2.22), site (OR 3.25, 95 percent CI 2.26-4.67) and type of insertion (OR 2.04, 95 percent CI 1.36-3.05) of catheter, diabetes mellitus (OR 7.78, 95 percent CI 4.59-13.21), infectious disease (OR 6.21, 95 percent CI 4.27-9.03) and burns (OR 3.96, 95 percent CI 3.26-4.82).

CONCLUSION

Phlebitis is still an important and ongoing problem in medical practice. In patients with diabetes mellitus and infectious diseases, more attention is needed.

Effects modification of iron hematoxylin on neuron staining

Iron weigert staining methods is used as nuclear staining. In present study we introduce a modification iron weigert hematoxylin for staining neuron without astrocytes. Whole brain of adult wistar rats (12-13 week old) were removed, immersed in formaldehyde fixative and embedded in paraffin. Sections, 5-7 microm (from brain cortex, hippocampus, cerebellum) divided to three groups: one for staining by Hematoxyllin and eosin, second for staining by cresyl fast violet (that specially performed for Nisl substances in neuron) and last for staining by modification iron hematoxyllin methods, but different in quantity and quality. In new method general and specific architecture of neuron, nucleus and nuclear envelope was clearly visible reactions of neuron were predominant. Astrocyte did not respond to staining methods. Also spines (axon) of purkinje cells clearly visible. Modification iron weigert hematoxylin can be replacement to cost and time consuming chemical staining method for staining neurons.

Conductometric simultaneous determination of acetic acid, monochloroacetic acid and trichloroacetic acid using orthogonal signal correction-partial least squares

A simultaneous conductometric titration method for determination of mixtures of acetic acid, monochloroacetic acid and trichloroacetic acid based on the multivariate calibration partial least squares is proposed. It is possible to obtain an adjustable model to relate squared concentration values of the mixtures used in the calibration range by conductance. The effect of orthogonal signal correction (OSC) as a preprocessing technique used to remove the information unrelated to the target variables is studied. The calibration model was build using conductometric titrations data of 16 mixtures of three acids. The concentration matrix was designed by a orthogonal design. The root mean squares error of prediction (RMSEP) for acetic acid, monochloroacetic acid and trichloroacetic acid with and without OSC were 0.08, 0.30 and 0.08, and 0.15, 0.40 and 0.18, respectively. The results obtained by OSC-PLS are better than the PLS and this indicate the successful application of the OSC filter as a good preprocessing method in multivariate calibration methods. The proposed procedure allows the simultaneous determination of these acids, in the synthetic mixtures.

Oral aspirin and ibuprofen increase cytokine-induced synthesis of IL-1 beta and of tumour necrosis factor-alpha ex vivo

We investigated the effect of oral aspirin and ibuprofen on the ex vivo synthesis of interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-2, IL-6, tumour necrosis factor-alpha (TNF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) by stimulated peripheral blood mononuclear cells (PBMC) from healthy volunteers. Seven volunteers took 325 mg of aspirin daily for 14 days. Three weeks after ending aspirin medication, ex vivo IL-1 beta and TNF synthesis induced by exogenous IL-1 alpha was elevated threefold compared to the pre-aspirin value (P = 0.01 and P = 0.005, respectively). Using lipopolysaccharide (LPS) as a stimulus, no influence of oral aspirin was observed. The increase in cytokine synthesis did not parallel decreased synthesis of prostaglandin E2 (PGE2). Seven weeks after discontinuation of aspirin, cytokine and PGE-2 production returned to pre-aspirin levels. Another seven volunteers took 200 mg of ibuprofen daily for 12 days. Again, there was no effect on LPS- or Staphylococcus epidermidis-induced cytokine synthesis. However, IL-1 alpha-induced synthesis of IL-1 beta was elevated to a mean individual increase of 538% (P < 0.001) and synthesis of TNF was elevated to 270% (P < 0.001) at the end of ibuprofen medication and 2 weeks after discontinuation of ibuprofen. There were parallel increases in PGE2 and both returned to their pre-ibuprofen levels 5 weeks after stopping. Although inhibitors of cyclo-oxygenase blunt PGE2-mediated symptoms such as fever and pain, we conclude that short term use of either aspirin or ibuprofen results in a 'rebound' increase in cytokine-induced cytokine synthesis that is not observed in LPS-induced cytokines.

Dietary supplementation with n-3 fatty acids suppresses interleukin-2 production and mononuclear cell proliferation

We studied the in vitro production of interleukin-2 in nine healthy volunteers who added 18 g/day of fish-oil concentrate rich in n-3 polyunsaturated fatty acids to their normal Western diet for a period of 6 weeks. Interleukin-2 synthesis from stimulated peripheral blood mononuclear cells was suppressed from 6.2 ng/ml at baseline to 2.2 ng/ml 10 weeks after the end of n-3 fatty acid supplementation (65% decrease; P = .04). At the same time phytohemagglutinin-induced proliferation of mononuclear cells was suppressed by 70% from the presupplement level. Interleukin-2 production returned to the premedication level at the end of the studies. The results suggest that the effect of dietary n-3 fatty acids in some diseases may be mediated in part by decreased production of interleukin-2 and decreased mononuclear cell proliferation.

Correlations and interactions in the production of interleukin-6 (IL-6), IL-1, and tumor necrosis factor (TNF) in human blood mononuclear cells: IL-6 suppresses IL-1 and TNF

Interleukin-6 (IL-6) shares several biologic properties with IL-1, including hematopoietin-1 activity and stimulation of T cells. Because many of their biologic activities overlap, we developed and used a specific radioimmunoassay (RIA) for IL-6 to compare production of this cytokine on a molar basis with that of IL-1 alpha, IL-1 beta, and tumor necrosis factor (TNF)alpha. The RIA correlated well with the hybridoma bioassay for IL-6 (r = .87, P less than .001). Freshly isolated human peripheral blood mononuclear cells (PBMC) cultured in the absence of stimuli did not produce IL-6 in most cases. Kinetics of secretion and cell-association of IL-6 were studied. In contrast to IL-1 alpha but similar to TNF, IL-6 was almost entirely secreted into the extracellular fluid. Incubation with different stimuli (lipopolysaccharide [LPS], phytohemagglutinin [PHA], Staphylococcus epidermidis, or IL-1 alpha) resulted in production of IL-6. However, on a molar basis PBMC produced approximately two to three times less IL-6 than IL-1 alpha, IL-1 beta, or TNF, regardless of the stimulus. The amount of IL-6 produced from PBMC was consistent when measured in the same subjects six time during a 12-week period. In a cohort of 38 donors, the coefficient of variation for IL-6 production was .32, compared with .92 for IL-1 beta and .96 for TNF. Comparing cytokine production by PBMC, there was a significant correlation between IL-6 and IL-1 beta (r = .72) and between IL-6 and TNF (r = .66). IL-6 did not stimulate IL-1 beta or TNF production, but suppressed IL-1 beta and TNF production induced by LPS or PHA by 30% (P less than .01). This suppression of IL-1 beta and TNF by IL-6 appears to be on the level of transcription.

In vitro production of IL 1 beta, IL 1 alpha, TNF and IL2 in healthy subjects: distribution, effect of cyclooxygenase inhibition and evidence of independent gene regulation

Numerous studies have reported altered in vitro cytokine production in various diseases. In the present study we used specific immunoassays to quantitate production of interleukin 1 beta (IL 1 beta), IL 1 alpha, tumor necrosis factor (TNF) and IL 2 from human peripheral blood mononuclear cells (PBMC). The distribution of cell-associated and secreted cytokines was studied in PBMC of 21 individuals; in response to lipopolysaccharide (LPS) the proportion of cell-associated IL 1 beta ranged from 13% to 56%, for IL 1 alpha 29% to 98%, and for TNF 2% to 17%. In a larger cohort of 32 subjects, the total amount of immunoreactive cytokines produced in response to LPS or phytohemagglutinin was normally distributed within the study group. Mean production of IL 1 alpha in response to LPS was 10.1 ng/ml and exceeded production of IL 1 beta (5.6 ng/ml) and TNF (2.2 ng/ml). The distribution pattern was characterized by high intersubject variability extending over two orders of magnitude and the presence of high and low "producers". Production of IL 1 alpha and IL 1 beta correlated (R = 0.69). In contrast, production of IL 1 beta did not correlate with production of TNF or IL 2. Indomethacin present during stimulation of PBMC increased the amount of IL 1 beta produced and showed a high correlation (R = 0.83) compared to cultures without indomethacin. Thus, low production of IL 1 beta in certain subjects appears not to be due to inhibitable levels of cyclooxygenase products. In a retrospective study, PBMC from 12 subjects who had taken oral cyclooxygenase inhibitors during the preceding 7 days produced 43% more IL 1 beta than subjects who did not take these drugs (p less than 0.05). These studies demonstrate that the amount of cytokine synthesized by PBMC (a) is regulated independently for IL 1, TNF and IL 2; (b) correlates for IL 1 beta and IL 1 alpha; (c) is intrinsic for low and high "producers", and (d) production of IL 1 beta increases with the use of oral cyclooxygenase inhibitors.

The effect of dietary supplementation with n-3 polyunsaturated fatty acids on the synthesis of interleukin-1 and tumor necrosis factor by mononuclear cells

We examined whether the synthesis of interleukin-1 or tumor necrosis factor, two cytokines with potent inflammatory activities, is influenced by dietary supplementation with n-3 fatty acids. Nine healthy volunteers added 18 g of fish-oil concentrate per day to their normal Western diet for six weeks. We used a radioimmunoassay to measure interleukin-1 (IL-1 beta and IL-1 alpha) and tumor necrosis factor produced in vitro by stimulated peripheral-blood mononuclear cells. With endotoxin as a stimulus, the synthesis of IL-1 beta was suppressed from 7.4 +/- 0.9 ng per milliliter at base line to 4.2 +/- 0.5 ng per milliliter after six weeks of supplementation (43 percent decrease; P = 0.048). Ten weeks after the end of n-3 supplementation, we observed a further decrease to 2.9 +/- 0.5 ng per milliliter (61 percent decrease; P = 0.005). The production of IL-1 alpha and tumor necrosis factor responded in a similar manner. Twenty weeks after the end of supplementation, the production of IL-1 beta, IL-1 alpha, and tumor necrosis factor had returned to the presupplement level. The decreased production of interleukin-1 and tumor necrosis factor was accompanied by a decreased ratio of arachidonic acid to eicosapentaenoic acid in the membrane phospholipids of mononuclear cells. We conclude that the synthesis of IL-1 beta, IL-1 alpha, and tumor necrosis factor can be suppressed by dietary supplementation with long-chain n-3 fatty acids. The reported antiinflammatory effect of these n-3 fatty acids may be mediated in part by their inhibitory effect on the production of interleukin-1 and tumor necrosis factor.

Measurement of immunoreactive interleukin-1 beta from human mononuclear cells: optimization of recovery, intrasubject consistency, and comparison with interleukin-1 alpha and tumor necrosis factor

Numerous studies have reported altered levels of in vitro production of the cytokines interleukin-1 (IL-1) and tumor necrosis factor (TNF) from blood leukocytes in various human disease states. Most of these studies have used bioassays which are vulnerable to inhibitors produced by these cells. Furthermore in vitro cytokine production is often assessed on a single occasion. The present study was designed to standardize stimulation conditions for in vitro IL-1 beta production and to employ a competitive radioimmunoassay (RIA) to demonstrate reproducibility and long-term variation of in vitro cytokine production in a cohort of healthy human subjects. We also examined relative amounts of immunoreactive IL-1 beta, IL-1 alpha, and TNF induced by the stimuli endotoxin, phytohemagglutinin, or Staphylococcus epidermidis. We show that the RIA can reliably detect IL-1 beta produced from mononuclear cells in concentrations as low as 115 pg/ml. Lysing cells by repeated freeze-thawing yields maximal recovery of total (i.e., secreted plus cell-associated) immunoreactive IL-1 beta, when compared to extraction with the detergent CHAPS or addition of protease inhibitors. Repeated measurement of in vitro cytokine production on different days within 1 week shows good reproducibility for a given individual and a given stimulus (variation coefficient 20 to 30%). Over a long time period (6 months) in vitro cytokine production is stable in some individuals but changes considerably in others. The soluble stimulus endotoxin induces twofold more IL-1 alpha than IL-1 beta or TNF; in contrast the phagocytic stimulus heat-killed S. epidermidis induces fourfold more IL-1 beta and TNF than IL-1 alpha. This distinct pattern of cytokine response indicates differential stimulation of the mononuclear cells by different stimuli. The results form the basis for studying in vitro cytokine production in different human disease states.