Microencapsulation of Lactobacillus plantarum in the alginate/chitosan improves immunity, disease resistance, and growth of Nile tilapia (Oreochromis niloticus)

This study evaluated the effects of microencapsulation of L. plantarum (as a probiotic) with chitosan/alginate biopolymers (MLCA) on innate immune response, disease resistance, and growth performance of Nile tilapia (Oreochromis niloticus). Four hundred and eighty fish were randomly distributed in glass tanks (150 L) and fed with diets including diet 1: control; diet 2: 10 g kg-1 microcapsules; diet 3: 108 CFU g-1 L. plantarum; and diet 4: 10 g kg-1 MLCA for 60 days. The hematology and biochemical indices, lysozyme activity, alternative complement activities, respiratory burst, serum bactericidal activity, as well as growth performance parameters (specific growth rate, feed conversion ratio) were analyzed. White blood cells, plasma protein and globulin concentration, serum lysozyme, and respiratory burst activities of fish were significantly increased (P < 0.05) in the MLCA diet. A challenge test against Streptococcus agalactiae, at the end of the experiment, showed the highest survival rate of the fish fed with MLCA. Moreover, the fish fed with MLCA showed a significant improvement in SGR (3.12 ± 0.18%) and FCR (1.23 ± 0.20) and had the highest growth performance. These results suggest longer stability of probiotics in the microcapsules, and their immunomodulatory effect can be considered a promising immunostimulant and growth enhancer in the Nile tilapia diet.

The hospitalization rate and clinical characteristics of mucormycosis prior and during COVID-19 pandemic: A single-center study

INTRODUCTION

There have been some reports of the association between SARS-CoV-2 infection and mucormycosis. This study aims to compare the hospitalization rates and clinical characteristics of mucormycosis before and during the COVID-19 pandemic.

METHODOLOGY

In this retrospective study, we compared the hospitalization rate of mucormycosis patients in Namazi hospital in Southern Iran for two periods of 40 months. We defined July 1st, 2018 to February 17th, 2020, as the pre-COVID-19 period and February 18th, 2020, to September 30th, 2021, as the COVID-19 period. In addition, a quadrupled group of hospitalized patients with age and sex-matched SARS-COV-2 infection without any sign of mucormycosis was selected as the control group for COVID-associated mucormycosis.

RESULT

In the total of 72 mucormycosis patients in the COVID period, 54 patients had a clinical history and a positive RT-PCR, which confirms the diagnosis of SARS-COV2 infection. The hospitalization rate of mucormycosis showed an increase of + 306% (95% CI: + 259%, + 353%) from a monthly average value of 0.26 (95% confidence interval (CI): 0.14, 0.38) in the pre-COVID period to 1.06 in the COVID period. The use of corticosteroids prior to the initiation of hospitalization (p ≤ 0.01), diabetes (DM) (p = 0.04), brain involvement (p = 0.03), orbit involvement (p = 0.04), and sphenoid sinus invasion (p ≤ 0.01) were more common in patients with mucormycosis during the COVID period.

CONCLUSIONS

In high-risk patients, especially diabetics, special care to avoid the development of mucormycosis must be taken into account in patients with SARS-COV-2 infection considered for treatment with corticosteroids.

Investigation of Job Fatigue, Quality of Life and Sleep of shift staff working in the electric distribution company of Ilam Province

Introduction: Shift work is one of the social phenomena that has its roots in the history of human origin and still exists today for economic and technological reasons. Due to the complications of shift work, the present study was conducted to investigate job fatigue, quality of life, and sleep of shift staff working in Ilam Electric Distribution Company. Materials and Methods: In this descriptive-analytical study, all shift workers of Ilam Electric Distribution Company were selected. Data collection tools included the Swedish Job Exhaustion Questionnaire, Quality of Life (SF-36), the Insomnia Assessment Questionnaire, and the Survey of shift workers (SOS). SPSS software version 26 was used to analyze data using independent sample T-Test, One-way ANOVA, and Chi-square tests.  Results: Pearson correlation test showed that there was a direct and positive correlation between age and physical function (r = 0.439; p = 0.022), smoking and sleep problems (r = 0.528; p = 0.006), and education and limitation of the role of emotional problems (r = 0.382; p = 0.049). Also, the was a significant indirect correlation was found between age and physical role limitation (r = - 0.501; p = 0.008), shift work with satisfaction with individual life (p <0.045), social life (p <0.038), family life (p <0.023) and family dissatisfaction. Conclusion: shift working has adverse effects on family satisfaction, circadian rhythms, digestive performance, and mental health. It is suggested that managers be more careful about working hours, work shifts, and rest times

Severe Hyperkalemia Masquerading as Acute Ischemic Stroke: A Case Report

Severe hyperkalemia usually presents as cardiac or neurologic manifestations. We report a case of a 63-year-old Caucasian woman, who was admitted to Namazi Hospital, affiliated with Shiraz University of Medical Sciences (Shiraz, Iran) in August 2019. The patient suffered from left-sided weakness and slurred speech for one hour prior to admission. Initially, the patient was treated for acute ischemic stroke, and an intravenous recombinant tissue plasminogen activator (IV-rTPA) was prescribed. However, further investigations showed severe hyperkalemia. Hemiparesis and slurred speech improved significantly with appropriate management of hyperkalemia. To the best of our knowledge, this is the first case of hyperkalemia masquerading as acute ischemic stroke without evidence of concomitant central nervous system malignancies, large vessel atherosclerosis, or recreational drug abuse. Stroke mimics due to hyperkalemia should be considered in any patient with simultaneous sudden onset of focal neurologic deficits and tall peaked T waves, particularly in the context of renal failure and a history of potassium-sparing drug use.

Role of adipokines in the ovarian function: Oogenesis and steroidogenesis

Adipokines are mainly produced by adipose tissue; however, their expression has been reported in other organs including female reproductive tissues. Therefore, adipokines have opened new avenues of research in female fertility. In this regard, studies reported different roles for certain adipokines in ovarian function, although the role of other recently identified adipokines is still controversial. It seems that adipokines are essential for normal ovarian function and their abnormal levels could be associated with ovarian-related disorders. The objective of this study is to review the available information regarding the role of adipokines in ovarian functions including follicular development, oogenesis and steroidogenesis and also their involvement in ovary-related disorders.

Clinical characteristics of psychogenic nonepileptic seizures across the lifespan: An international retrospective study

PURPOSE

Previous studies from a few countries have reported semiological differences in younger children compared with adolescents or adults with psychogenic nonepileptic seizures (PNESs). This study tested the hypothesis that semiological, demographic, and historical risk factors vary with different ages of PNES onset in a large cohort from different countries.

METHODS

In this retrospective study, we investigated patients consecutively referred for PNES, who were admitted to epilepsy monitoring units in Iran, Brazil, Venezuela, Canada, Argentina, and USA. Age, gender, age at seizure onset, seizure semiology, and factors predisposing to PNES (abuse, stressors) were documented according to routine diagnostic practices at each center. Participants were grouped according to their age at onset (i.e., childhood, adolescence, or adulthood).

RESULTS

A total of 448 patients were studied. Female predominance was associated with adolescent- (85/122, 70%) and adult-onset (190/270, 70%) but not in childhood-onset PNES (28/56, 50%) (p = 0.011). Event frequency in the month preceding the diagnosis was higher in the childhood- [x¯ = 50, standard deviation (sd) = 82, p = 0.025] versus adolescent- (x¯ = 24, sd = 36) or adult-onset groups (x¯ = 29, sd = 61). Significant between-group differences were observed for generalized body movements (p = 0.0001) and ictal injury (p = 0.027), suggesting more severe ictal presentations in adult-onset PNES compared with younger ages. Adult-onset patients were also more likely to be taking an unnecessary antiepileptic medication (p = 0.010).

CONCLUSION

While PNES may present at any age, there appear to be notable differences across the lifespan with respect to some of the clinical characteristics. Further international and cross-cultural studies may reveal other interesting characteristics of PNES.

Adult-onset psychogenic nonepileptic seizures: A multicenter international study

PURPOSE

The aim of this multicenter international cross-cultural study was to compare clinical variables in a large sample of people with adult-onset psychogenic nonepileptic seizures (PNES).

METHODS

In this retrospective study, we evaluated persons with documented PNES, who were older than 16 years of age at the onset, from four countries (i.e., Iran, Brazil, Venezuela, and Argentina) regarding their age, gender, PNES semiology, and possible predisposing factors.

RESULTS

We included 389 patients (244 from Iran, 66 from Brazil, 51 from Venezuela, and 28 from Argentina). Age at diagnosis was 32 ± 9 years (range: 17-64 years), and age at the onset of seizures was 27 ± 8 years (range: 17-49 years). There was a female predominance in all countries. The demographic characteristics and factors associated with PNES were similar among the countries. However, there were significant semiological differences among the countries.

CONCLUSION

This study corroborates the notion that PNES share more similarities than differences cross-culturally and across international borders. However, the background determined by cultural, ethnic, and religious differences may influence the semiology of PNES. Further cross-cultural studies involving more than two continents may advance our understanding of PNES.

Why is psychogenic nonepileptic seizure diagnosis missed? A retrospective study

PURPOSE

The aim of this retrospective study was to scrutinize factors that are associated with a delay in making the diagnosis of psychogenic nonepileptic seizures (PNES).

METHODS

In this study, patients with PNES, who were investigated at Shiraz Comprehensive Epilepsy Center, Iran, from 2008 to 2019, were studied. We categorized the patients into the following: 1. those with a definite diagnosis of PNES in less than a year since the onset of their attacks; 2. those with a definite diagnosis of PNES later than 10 years since the onset of their attacks.

RESULTS

During the study period, 330 patients were recorded. In 98 patients (30%), the diagnosis of PNES was made in less than a year since their seizure onset. In 67 patients (20%), the diagnosis of PNES was made later than 10 years since their seizure onset. Taking antiepileptic drugs (AEDs) (odds ratio (OR) = 6) and a history of ictal injury (OR = 3.6) had a positive association, and age at the onset (OR = 0.8) had an inverse association with a delay in receiving a definite diagnosis of PNES (p = 0.0001).

CONCLUSION

Some demographic variables (i.e., early age at the onset of seizures), patients' clinical variables (i.e., severe seizure manifestations such as ictal injury), and finally, some physician-related variables (i.e., prescribing AEDs) have significant associations with a delay in making a definite diagnosis of PNES.

Sex differences in demographic and clinical characteristics of psychogenic nonepileptic seizures: A retrospective multicenter international study

PURPOSE

Sex-related differences have been reported in patients with neurological and psychiatric disorders. It is also plausible to assume that there might be differences between females and males with psychogenic nonepileptic seizures (PNES).

METHODS

In this retrospective study, we investigated patients with PNES, who were admitted to the epilepsy monitoring units at centers in Iran, the USA, Canada, Brazil, Argentina, and Venezuela. Age, sex, age at seizure onset, seizure semiology, factors potentially predisposing to PNES, and video-electroencephalography recording of all patients were registered routinely.

RESULTS

Four hundred and fifty-one patients had PNES-only and were eligible for inclusion; 305 patients (67.6%) were females. We executed a logistic regression analysis, evaluating significant variables in univariate analyses (i.e., age, age at onset, aura, presence of historical sexual or physical abuse, and family dysfunction). The only variables retaining significance were historical sexual abuse (p = 0.005) and presence of aura (p = 0.01); physical abuse was borderline significant (p = 0.05) (all three were more prevalent among females).

CONCLUSION

Similarities between females and males outweigh the differences with regard to the demographic and clinical characteristics of PNES. However, notable differences are that females more often report lifetime adverse experiences (sexual and probably physical abuse) and auras. While social, psychological, and genetic factors may interact with lifetime adverse experiences in the inception of PNES, the link is not yet clear. This is an interesting avenue for future studies.

Parental consanguinity in patients with psychogenic nonepileptic seizures

PURPOSE

The aim of this study was to investigate the rate of consanguinity of parents of the patients with psychogenic nonepileptic seizures (PNES). This would provide important information for future studies on the potential genetic bases of PNES.

METHODS

In this retrospective study, all patients with PNES, who were studied at Shiraz Comprehensive Epilepsy Center at Shiraz University of Medical Sciences, from 2008 to 2018, were recruited. We categorized the patients as (1) no consanguineous marriage of the parents and (2) with consanguineous marriage of the parents.

RESULTS

Three-hundred and sixteen patients had the data on their parental consanguinity available and were studied. The sex ratio (female:male) of the patients was 1.92 (208:108). Parents of 110 (35%) patients had consanguineous marriage, and parents of 206 (65%) patients did not. Demographic variables, seizure-related variables, PNES-associated factors, and the use of antiepileptic drugs were not significantly associated with parental consanguinity in the patients.

CONCLUSIONS

In this study, we observed that more than one-third of the patients with PNES had parental consanguinity. This rate is very similar to the rate of consanguinity in the general population in Iran.

Psychogenic nonepileptic seizures in children and adolescents: An international cross-cultural study

PURPOSE

We compared various clinical characteristics of psychogenic nonepileptic seizures (PNES) between young patients from Iran, Saudi Arabia, and Canada, three nations with significantly different socioeconomic and demographic characteristics. This international cross-cultural comparative study may advance our knowledge and understanding of PNES in children and adolescents across the cultures and borders.

METHODS

In this retrospective study, we investigated all patients 16 years of age or younger, with PNES admitted to the epilepsy monitoring units at one center in Iran, one center in Saudi Arabia, and one center in Canada. Age, gender, age at seizure onset, seizure semiology, seizure frequency, factors potentially predisposing to PNES, and video-electroencephalography (EEG) recording of all patients were registered routinely and compared between the nations.

RESULTS

Fifty-one patients were studied (22 from Iran, 14 from Saudi Arabia, and 15 from Canada). Age at the diagnosis was 13.4 ± 2.2 years (range: 8-16 years), and age at the onset of seizures was 12.3 ± 2.7 years (range: 5-16 years). Demographic and clinical characteristics of and associated factors in the patients among the three nations were not significantly different. Twenty-six (51%) patients were taking antiepileptic drugs at the time of diagnosis; the difference was not statistically significant between the nations (13 patients in Iran, 6 in Saudi Arabia, and 7 patients in Canada; P = 0.5).

CONCLUSION

Young patients with PNES across borders and between cultures share more similarities than differences with regard to their demographic and clinical characteristics.

Fractal properties and morphological investigation of Nano hydrochlorothiazide is used to treat hypertension

PURPOSE

High blood pressure (hypertension) is a relatively common condition that increases blood pressure in the arteries abnormally, causing problems such as heart disease and stroke. Blood pressure is a force that is felt through the walls of the blood vessels and has a direct relationship to the power of pumping the heart and vascular resistance to the blood flow. One of the lowing of blood pressure medications is hydrochlorothiazide (Hctz) which is used to treat high blood pressure and swelling from heart failure, liver damage, and other minor actions.

PROCEDURES

This study explains the effectiveness of Hctz with the help of "fractal dimension". To perfect investigate the fractal dimension, we used the Hctz drug nanoparticle form then using MATLAB software, homogeneity levels or heterogeneity of Nano Hctz using SEM images were computed.

RESULTS

We calculated histogram plot with SEM image by MATLAB software which that its standard deviation was eclose to zero and it can explain that the scattering of data is low and their amount is in one suffering. Fractal dimensions obtained from Matlab and SPSS software for normal distribution, correlation, standard deviation, mean, cumulative frequency and variance analysis were analyzed.

CONCLUSIONS

In this research, the association between Hctz treatment effects with the point of view of the fractal dimension of the drug was demonstrated to prove the properties of the drug in the body. in the near future, drug fractal studies can improve the development of new drugs and treatments with minimal cost than clinical approaches by linking chemistry, mathematical sciences and pharmaceutical sciences.

The effect of minocycline on indolamine 2, 3 dioxygenase expression and the levels of kynurenic acid and quinolinic acid in LPS-activated primary rat microglia

Microglia are one of the most important neural cells in the central nervous system (CNS) which account for 10-15% of all cells found in the brain. A vast majority of studies indicate that microglia play a pivotal role in protection and damage of the CNS. It has been shown that microglia are mainly scavenger cells but also produce a barrage of factors that are involved in tissue repair and neural regeneration. Several lines of evidence indicate that unregulated activation of microglia in response to either endogenous or exogenous insults results in the production of toxic factors that propagate neuronal injury. Studies demonstrated that the activated microglia secret the excessive amounts of quinolinic acid (QA) and kynurenic acid (KYNA) which are highly toxic for the neuronal cells. In line with this, indolamine 2, 3 dioxygenase (IDO), an enzyme producing KYNA and QA has been shown to be elevated during the inflammation in microglia. In this study, we established primary microglial cell cultures obtained from cerebral cortices of 1-day neonatal Wistar rats. Minocycline (20-60 µM) or its vehicle was added to the culture media 60 min prior to 48 h incubation with lipopolysaccharide (LPS; 10 ng/mL). Using a specific process of adhesion and shaking of the cultured glial cells, a purified culture of approximately 94% enriched microglia was obtained and then, corroborated by immunocytochemistry (ICC). The cell viability after minocycline treatments was assessed using the MTT colorimetric assay. The expression of IDO was evaluated using qPCR. The levels of KYNA and QA were determined using enzyme-linked immunosorbent assay (ELISA). The results showed that minocycline significantly decreased the levels of both KYNA and QA in glia cells exposed to LPS. Moreover, minocycline decreased the expression of IDO in treated LPS-induced microglia. It seems that minocycline has a potent ability to oppress the inflammatory process via the decrease in production of IDO expression and the concentrations of KYNA and QA.

Abstract PR05: Systematic forward genetic screens in haploid human cells reveal new players and regulatory mechanisms in Wnt signaling

Wnt signaling is at the core of animal development and regeneration. It controls cell proliferation, differentiation and survival. In humans, defective Wnt signaling leads to several forms of cancer, most notably colorectal cancer (CRC). A convergence of methodological advances enabled us to do a systematic forward genetic analysis of canonical Wnt signaling in human cells, revealing new players and regulatory mechanisms. Using HAP1 cells, a haploid human cell line, we conducted a set of genome-wide screens to interrogate the Wnt pathway under normal and pathological conditions. We constructed a HAP1 line harboring a Wnt-responsive GFP reporter, mutagenized the cells by insertion of a gene trap retrovirus throughout the haploid genome, and sorted for cells exhibiting phenotypes of interest using FACS. By setting appropriate gates we enriched for negative and positive regulators of the pathway. These screens yielded many known players as well as a new transcription factor, TFAP4, required for signaling downstream of β-catenin. Unexpectedly AXIN2, a scaffold in the β-catenin destruction complex, was a prominent hit in the screen for positive regulators. However, the distribution of gene trap insertions in AXIN2 suggested that truncation of the last one or two exons encompassing the DAX domain, as opposed to disruption of the entire AXIN2 gene, was responsible for the observed phenotype. Follow-up analysis of cells in which AXIN1 was eliminated and AXIN2 C-terminal truncations were generated at the single endogenous locus confirmed that this domain is dispensable for destruction complex function. Furthermore, in these cells responsiveness to Wnt was only partially diminished, suggesting that the DAX domain is not essential for transduction of the Wnt signal from the receptor. Instead we show that the C-terminus is involved in regulating Axin2 protein levels. Using CRISPR/CAS9 we then generated haploid cell lines lacking adenomatous polyposis coli (APC), a scaffold in the β-catenin destruction complex, or casein kinase α (CK1α), the priming kinase for β-catenin degradation. These lines have constitutive Wnt signaling activity, and the former recapitulates the APC mutations found in CRC patients. We conducted synthetic genome-wide screens looking for modifiers of these mutations in an otherwise isogenic background. We found that in APC-null cells, deletion of the RNA binding protein SERBP1 reduces β-catenin protein levels significantly, restoring normal levels of Wnt-stimulated signaling. In CK1α-null cells, deletion of the E3 ubiquitin ligase HUWE1 decreases Wnt signaling by over 85% with only a minor reduction of β-catenin protein level. This defect is specific to the CK1α genetic background, since deletion of HUWE1 in APC-null cells has no effect on signaling. These results suggest a destruction complex independent role of CK1α in Wnt signaling, mediated by HUWE1. Our findings are supported by experiments in model organisms. The experimental approaches used in this study are generally applicable to other signaling pathways and more broadly to any cellular process in which a phenotypic readout can be used to enrich for mutant cells. The combination of forward genetics in haploid cells and CRISPR/CAS9-based genome engineering brings to bear on cultured human cells the immense power of genetics traditionally limited to model organisms such as yeast.

This abstract is also presented as Poster B11.

Citation Format: Andres M. Lebensohn, Ramin Dubey, Leif R. Neitzel, Ofelia Tacchelly, Caleb D. Marceau, Zahra Bahrami, Amanda G. Hansen, Yashi Ahmed, Ethan Lee, Jan Carette, Rajat Rohatgi. Systematic forward genetic screens in haploid human cells reveal new players and regulatory mechanisms in Wnt signaling. [abstract]. In: Proceedings of the AACR Special Conference: Developmental Biology and Cancer; Nov 30-Dec 3, 2015; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(4_Suppl):Abstract nr PR05.

Correlation between follicular fluid 25-OH vitamin D and assisted reproductive outcomes

BACKGROUND

Vitamin D in complex with its receptor by regulating gene expression, endometrium immune response and stimulation of endometrium decidualization can be involved in implantation. So, it seems that the amount of vitamin D in follicular fluids (FF) may have an association with ART success.

OBJECTIVE

First, we intended to investigate the possible association between levels of follicular fluids 25-OH vitamin D with assisted reproductive outcomes. Second, we examined relationship between 25-OH vitamin D levels with number and quality of oocytes.

MATERIALS AND METHODS

In a prospective study, 80 infertile female candidates for IVF/ICSI were enrolled. Blood samples (on the day of human chorionic gonadotropin administration) and follicular fluids were taken, and then levels of serum estradiol and follicular fluids 25-OH vitamin D were measured. Also clinical characteristics of patients (duration of infertility, causes of infertility, menstrual status), number and quality of oocytes, number of fertilized oocytes, estradiol levels, and clinical pregnancy were evaluated.

RESULTS

Concentration of FF 25-OH vitamin D in pregnant women was significantly higher than non-pregnant women (p=0.007) but there were no significant differences in age, body mass index (BMI), duration of infertility, menstrual status, number of oocytes, oocytes quality, number of fertilized oocytes, and serum estradiol levels between the two groups. Statistically positive correlation was found between 25-OH vitamin D levels with patient age and implantation rate (r=0.264, p=0.018 and r=0.301, p=0.007 respectively).

CONCLUSION

The obtained results suggest that vitamin D without affecting the number and quality of oocytes can independently improve implantation rate and IVF outcome.

Application of the Information-Motivation and Behavioral Skills (IMB) model in risky sexual behaviors amongst male students

As AIDS is not merely a hygienic problem but a disease that creates a great deal of economic, cultural, and social problems, it is necessary for most of the state and nongovernmental organizations and individuals to participate in both controlling AIDS and preventing it. As no effective vaccine or therapy for this disease exists currently, the only method for avoiding being afflicted by this disease is prevention. The present study aims to examine the Information-Motivation and Behavioral Skills (IMB) model in risky sexual behaviors. For this purpose, a group of 151 male students was sampled using a multistage random sampling method to complete the quality of HIV information questionnaire, national AIDS questionnaire, international AIDS questionnaire and global positive attitude to AIDS questionnaire. The results show that there is a significant relationship between the perception of HIV infection risk and sexual behavior. Thus, the perception of risk is considered the first step toward modifying sexual behaviors from risk-taking behaviors to safer behaviors.

Effect of testosterone on thyroid weight and function in iodine deficient castrated rats

The prevalence of goiter, especially in iodine deficient regions, is higher in women than in men. This investigation was conducted to determine the effect of testosterone on thyroid weight and function in both normal iodine deficient and castrated rats. Male Wistar rats were divided into 6 groups of 7 animals each: castrated hormone treated (C+T); castrated nonhormone treated (C+NT); normal (N), iodine deficient diet, castrated hormone treated (ID+C+T); castrated iodine deficient diet, nonhormone treated (ID+C+NT); and normal iodine deficient diet (ID+N). Three weeks after castration, C+T and ID+C+T groups received daily intraperitoneal injections of 1 mg/kg testosterone enanthate, for 9 weeks. At the end, we measured thyroid weight and serum testosterone, T(4), free T(4), T3, and TSH, and urinary iodine concentrations. Serum testosterone level significantly decreased in the C+NT and ID+C+NT groups (p<0.001). In ID groups, serum TSH, T(3) and thyroid weight levels increased significantly and serum T4 and free T (4) levels decreased significantly as compared to iodine sufficient groups (p<0.001). ID+C+NT group, had higher serum TSH and thyroid weight and lower serum-free T4 than the ID+C+T and ID+N groups (p<0.01). The C+NT group had higher serum TSH and lower serum-free T(4) than the C+T and N groups (p<0.01). These results suggest that testosterone decreases thyroid enlargement and prevents the fall in free T(4) levels in ID castrated rats, which may explain the lower incidence of goiter in men than women in iodine deficient regions.