In vitro evaluation of aliphatic fatty alcohol metabolites of Perseaamericana seed as potential antimalarial and antimicrobial agents.

Perseaamericana Mill (Lauraceae) is a local medicinal plant used in Nigerian ethnomedicine as antimalarial. The aqueous decoction of the root part is a potent remedy against bacterial infections. Hence, the need to investigate the phytochemical and biological activities (antimicrobial and antiplasmodial) of the root back of Perseaamericana. Chromatographic and spectroscopic techniques were used in the identification and purification of metabolites, which were assayed for antimalarial and antimicrobial activities using Plasmodium falciparum and a panel of microorganisms. From the seeds of P. americana, five known 1, 2, 4-dihydroxy derivatives aliphatic alcohols, called avocadenols were isolated and identified by spectroscopic methods including 1D- and 2D NMR, and comparison with reported data in literature. Antifungal activity for 1, 2, 4-Trihydroxyheptadec-6-en-16-yne (5) (IC50< 8 µg/mL) against all the fungal strains and S. areus, and antimalarial activity for compounds 1, 2, 4-Trihydroxyheptadec-16-ene (1) and 1, 2, 4-tetrahydroxyheptadecane-6, 16-diene(2) (IC50 = 1.6 and 1.4 µg/mL for the D6 clone, respectively, and 2.1 and 1.4 µg/mL for the W2 clone, respectively) was observed. The fatty alcohols 1, 2, 4-tetrahydroxyheptadecane-6, 16-diene(2); 1, 2, 4-Trihydroxyheptadec-16-yne(3) and 1, 2, 4-Trihydroxyheptadecane(4) also exhibited promising in vitro antibacterial activity against a panel of pathogenic bacteria S. areus, methicillin resistant S. areus and E. coli at IC50 values of 21.1, 8, 200 µg/mL), (3.259, 86.32 µg/mL) and (17.18, 8.26 and 200 µg/mL), respectively. The results of this study provide evidence that the fatty alcohols are a promising class of antimalarial and antimicrobial agents.

Thyroid volume, iodine intake, autoimmune thyroid disorders, inborn factors, and endocrine disruptors: twenty-year studies of multiple effects puzzle in Slovakia.

OBJECTIVE: The aim of this study was to evaluate multiple interrelations between several endogenous and exogenous effects and the thyroid volume and function in large groups of children, adolescents, and adults with a sufficient whole life intake of the iodine. SUBJECTS AND METHODS: The data were obtained either by cross sectioned or longitudinal studies in a total of 4998 children and adolescents (aged 7 to 17 years) and 2501 adults (1071 males and 1430 females aged 20-75 years). Thyroid volume (ThV) was measured by ultrasound, antibodies, and hormones by electrochemiluminiscent immunoassay, and endocrine disruptors (EDs, polychlorinated biphenyls-PCB, dichlorodiethyl-ichloroethylene-DDE, and hexachlorobenzene-HCB) by high resolution gas chromatography/mass spectrometry. RESULTS: 1. In large groups of boys and girls of age 7, 10, 13 or 17 years, the ThV was significantly higher in the 10th decile than in pooled nine lower deciles. Moreover, in 17-year old subjects significantly higher prevalence of hypoechogenicity by ultrasound, positive thyroperoxidase antibodies (TPOab), and increased thyrotropin (TSH) levels were found in the 10th decile. 2. In a small group of children, some individuals revealed consistently higher ThV during the whole 7-year follow-up period irrespective of supplementation with iodine. 3. In 325 sibling pairs of age 10-19 years, born within three years, three groups with different ThV/m2 of body surface were distinguished: Group A (183 pairs having both ThVs small), Group B (103 pairs having both ThVs large); Group C (33 pairs having one ThV small and the other one large). Similar aggregation of ThVs in three groups was observed in 13 pairs of discordant twins and 19 sibling triads in which all the siblings were born within four years. 4. In 42 concordant twins, several pairs had ThV nearly twice as high (in terms of both plain ThV or ThV/m2 of the body surface) as several other pairs of the same age which is assumed to be a result of a genetic background. 5. In large cohorts of males and females, a highly significant positive correlation was found between the ThV and high level of TPOab on one side and EDs on the other side. However, in nearly the same numbers of subjects with low TPOab, negative correlation was seen between ThV and disruptors. These observations may apparently support the synergic effect of the autoimmunity and EDs on the thyroid function. CONCLUSIONS: Several cases of an excessive thyroid growth in the iodine replenished children, adolescents, and adults may apparently result from the autoimmune thyroiditis, probably induced by immunogenic action of iodine in presumably disposed individuals. However, in some cases even simultaneous participation of EDs can not be excluded. Some observations have also suggested that excessive thyroid growth in the iodine replenished adolescent and adult population which was equally exposed to disruptors may also result from other reasons as the unfavorable hereditary background.

[New aspects of the epidemiology of goitre]. / Nové pohl'ady na epidemiológiu tyreopatií.

Due to successful progress in monitored iodine prophylaxis of iodine deficiency during the last decades the prevalence of endemic goitre in several countries considerably decreased. Nevertheless, epidemiological studies have been also indicating a certain prevalence of small thyroids in the areas of iodine deficiency too, and, vice versa, that even after successful iodine prophylaxis the thyroid volume (ThV) is not equally decreasing in all subjects and goitre does still exist. This phenomenom has been called sporadic goitre and hereditary etiological factors were suspected. It is shown that after 40 years of successfully monitored and mandatory consumption of iodized salt in Slovakia the distribution of ThV in 2661 adults has considerably decreased as compared to that of 1380 adults from Germany and Denmark where median iodine deficiency was still present around 1990. However, in spite of that, in those 2661 adults from Slovakia the average ThV in the upper quartile was 22.5 ml which was 4-times higher than the value in the lower quartile (6.3 ml) or about twice as much as that in the second (9.4 ml) or third quartile (12.7 ml). Such differences possibly cannot be explained by considerable differences in life-long iodine intake any more and that is the reason why some factors different from iodine deficiency should be taken into account. Among them perhaps hereditary factors (including ethnical and autoimmune ones) and environmental factors (such as persistent chlorinated pollutants) should be considered first. It is postulated that sufficient iodine intake in Slovakia for last 40-50 years is a prerequisite for evaluating the role of such factors. Short overview of epidemiological studies from Slovakia published elsewhere is presented showing possible participation of hereditary factors. Thus, one study showed increased thyroid growth in a group of children followed for 7 years which was independent of iodine supplementation. Another study showed significantly different ThV in several pairs of siblings born within the interval of less than 24 months. Since such siblings took the same meals for the whole life in the same family and in the same school, they apparently had about the same life-long intake of iodine and thus the differences in ThV cannot result from iodine deficiency of one member of the pair. In addition, possible effect of environmental pollutants on ThV in a cohort of more than 2 000 adults with the same long-term iodine intake was observed. Finally, it is underlined that the upper limit of optimal iodine intake starts to be equally important as the lower limit and that such circumstance turns out to be of considerable importance. Japan is presented as a country with historically permanent very high iodine intake where any problem of endemic goitre from iodine deficiency never existed. However, possibly reversible goitre from megadoses of iodine exists, while the question of prevalence of autoimmune thyroid disorders does not seem to be definitely solved because of the lack of large epidemiological surveys in general population.

Recognition of a subgroup of adolescents with rapidly growing thyroids under iodine-replete conditions: seven year follow-up.

OBJECTIVE: To evaluate whether small iodine supplements decrease the incidence of adolescent thyroid hypertrophy in an iodine-sufficient population or whether such thyroid enlargement should be considered an inevitable physiological phenomenon. DESIGN: Beginning in September 1991 (after an initial examination in September 1990), 54 11-year-old children in Bardejov, Slovakia were given small iodine supplements (Thyrojod depot tablets containing 1530 microg iodide) every 2 weeks for 2 years followed by once weekly for 2 years. A second group of 63 children served as controls. In June 1995, there were still 52 treated and 60 control children in the study and these were examined; 44 treated and 48 control children remained in the study until June 1997. METHODS: In 1990, 1993, 1995, 1996 and 1997 the thyroid volume (ThV) was measured by ultrasound. Serum levels of TSH, thyroglobulin, total and free thyroxine and tri-iodothyronine and anti-thyroid peroxidase (anti-TPO), anti-thyroglobulin (anti-TG) and anti-TSH receptor (TSR) antibodies were estimated in 1990 and 1994, while only TSH, and anti-TPO and anti-TSR antibodies were measured in 1997. RESULTS: There was no difference between the groups at any interval in the serum levels of the hormones measured. Marginally increased TSH was found in two treated and two control children. Anti-TSR antibodies were negative in all children, while anti-TPO and anti-TG antibodies were found in one treated and four control children. At the age of 10 years (1990), 84% of all ThVs were less than 4 ml, indicating a previous life-long sufficient iodine intake. After the treatment was completed (June 1995), a significant difference in ThV (P < 0.04) was found between the whole treated (5.78 +/- 0.19 ml) and the whole control group (6.56 +/- 0.30 ml). However, there was already a marked difference in the 75th percentile (6.4 ml in treated vs 8.5 ml in controls) due to more rapid thyroid growth in certain children of the control group (ThV > 7.0 ml in 6/52 treated children vs 24/60 controls; P < 0.01). Since such differences were much higher in 1997, the children in each group whose ThV was in the range of the upper 25% in 1997 were retrospectively evaluated as arbitrary separate subgroups in all the time intervals and compared with the remaining 75% of children who showed moderate thyroid growth rate. Two years after the termination of treatment (June 1997), excessive thyroid growth continued in the upper quarter of 12 controls with the highest ThV (13.60 +/- 0.40 ml or 7.60 +/- 0.29 ml/m2; 12/12 with ThV > 11.0 ml), and a similar subgroup now also appeared in 11 previously treated children (10.79 +/- 0.51 ml or 6.19 +/- 0.30 ml/m2; 5/11 with ThV > 11.0 ml). At the same time, ThV in the remaining 75% of both control (8.12 +/- 0.38 ml or 4.82 +/- 0.17 ml/m2; 3/36 with ThV > 11.0 ml) and treated (7.20 +/- 0.30 ml or 4.39 +/- 0.17 ml/m2; 0/33 with ThV > 11.0 ml) children was significantly less (P < 0.01 to P < 0.001) than that in the appropriate rapidly growing subgroups. During the whole observation period (1990-1997), no difference was found between treated and control subgroups with moderate thyroid growth. CONCLUSIONS: Since iodine intake in Slovakia has been adequate for decades and sporadic iodine deficiency is highly unlikely, the observed excessive thyroid growth in certain adolescents may result from causes other than simple iodine deficiency (e.g. hereditary), which are nevertheless ameliorated by small iodine supplements. The question remains whether such a subgroup with rapidly growing thyroids should be included in the range of normal thyroid volumes in adolescents.

Fatty acid composition in fractions of structural and storage lipids in liver and skeletal muscle of hereditary hypertriglyceridemic rats.

The fatty acid (FA) compositions of liver and skeletal muscle structural lipids, overall phospholipids and phosphatidylcholine, and triglycerides (TG) were determined in the hereditary hypertriglyceridemic (HTG) rat, a nonobese animal model of the insulin resistance syndrome. Four groups of HTG rats and four groups of control animals were fed equal-energy diets for two weeks: basal (B), high-sucrose (HS), or fish oil-supplemented basal (BFO) or high-sucrose (HSFO) diets. In the liver of HTG rats, a decrease of n-6 long-chain polyunsaturated FA (PUFA), especially in 20:4n-6, in comparison with controls was found. Moreover, a concomitant accumulation of 18:2n-6 in structural lipids was observed. These differences were more pronounced in liver than in skeletal muscle. HS feeding raised the proportion of 18:1n-9 and decreased 18:2n-6 in lipid fractions. In both tissues and in both strains, the amounts of long-chain n-3 PUFA, as well as the level of total C20-22 PUFA, went up after fish oil feeding. However, the effects were somewhat less pronounced in the HTG rats. The increase in n-3 PUFA occurred mainly at the expense of reduced levels of 18:2n-6 in structural lipids and of 18:1n-9 in triglycerides. These changes were associated, in companion studies reported in this volume, with improved insulin action in HTG rats. In conclusion, the FA composition in lipid subclasses of HTG rats differs significantly from the controls mainly in liver structural lipids, suggesting the impairment of PUFA desaturation. Dietary change effected a similar modulation of FA profile across both strains, with fish oil increasing the levels of long-chain PUFA toward control values in the NTG rats. The HTG rat thus provides an interesting animal model for the study of impaired fatty acid metabolism.

Thyroid volume and urinary iodine in school children and adolescents in Slovakia after 40 years of iodine prophylaxis.

The thyroid volume (by ultrasonographic volumetry) was estimated in 4,254 schoolchildren and adolescents 6-18 years of age from 12 districts of Slovakia and urinary iodine (by dry alkaline ashing followed by spectrophotometry) in 1,174 spot urine samples. No differences in thyroid volume or in iodine excretion between individual districts were found. Similarly, no differences in thyroid volume between sexes were found up to the age of 14 years, however, thereafter, such volumes were considerably higher in boys. When comparing our cummulated data with those reported by others for a population with optimal iodine intake, it was found: 1. the medians for most of the examined age groups were slightly higher, 2. the percentage of values which were higher than 97 percentiles of normal population was 3.01 for the age of 6-14 years, while that for the age of 15-18 years was 9.04. Only 35.9% of all values of urinary iodine were in the optimal range (i.e. 10-20 mud/dl), while 56.1 were less than 10 micrograms/dl and 15.9% less than 5 micrograms/dl, the remaining 8.0% over 20 micrograms/dl. In spite of long-term iodine prophylaxis (since 1949), the intake of iodine apparently is still not satisfactory, since a considerable amount of individuals appeared to be iodine deficient on the day of examination. Iodine intake, however, may be marginally sufficient up to the age of about 13-14 years, while later a higher number of enlarged thyroids was found which may be classified as goitre endemy grade I.

Lesions of some central nervous structures result in altered pituitary-thyroid response to acute decrease of blood thyroid hormone level.

Eight groups (3--6 animals each) of rats weighing 350--400 g were subjected to electrolytic lesions of various parts of habenular, thalamic and hypothalamic areas of brain. On the 6th day after the lesion the level of blood thyroid hormone was acutely decreased with the aid of isovolemic exchange transfusion (IET) of thyroid hormone free blood suspension. The level of thyroxine (T4) in plasma was measured before and during 180 min after IET with the aid of specific radioimmunoassay and the changes of its post-transfusion level were evaluated. It was found that in three groups of animals bearing large bilateral lesions either in lateral ventral thalamus or in a central inferior thalamus the response of T4 level during the post-transfusion period is similar to that found in intact control groups from previous experiments. This consists in an increase of T4 level nearly to the initial value within about 120--150 min after IET. In contrast, there was only a slight post-transfusion increase of T4 level in one group with small central lesion in medial superior thalamus and no increase in two groups bilaterally lesioned in habenular area and in another two groups lesioned either in a central part of dorsal hypothalamus or in a central dorsal part of ventral basal hypothalamus. It was concluded that some parts of brain may be involved in managing the appropriate response of pituitary-thyroid axis to acute decrease of thyroid hormone level, no plausible explanation of the mechanism ofthe observed phenomena being offered.

Acute decrease of blood thyroid hormone by isovolemic exchange transfusion as a stimulus for pulse TSH release and its modifications by CNS Lesions.

The level of thyroid hormone in blood has been acutely decreased by about 20--30% within 20 min with the aid of isovolemic exchange transfusion (IET) of thyroid hormone free blood cell suspension (THFBCS) in three groups of rats: (1) intact control (C); (2) median eminence (ME)-lesioned; (3) thalamus (TH)-lesioned. The levels of thyroxine (T4) and TSH were measured by specific radioimmunoassay (RIA) before the transfusion and for 180 min after that. The level of T4 increased to the initial value at about 120 min after IET in C and ME-lesioned rats, while in TH it remained decreased until 180 min. Furthermore, at the end of IET the level of TSH in C and ME-lesioned rats was about 2--3 time higher than the initial value and its continuous decrease was observed until 180 min. In contrast, in TH-lesioned rats the increase of TSH level was delayed, being significant at 60 min only. It was concluded that IET of THFBCS acts as a stimulus of acute TSH release which was remarkably inhibited in TH-lesioned animals. In addition, the destruction of most of the ME did not apparently influence this response, as shown by essentially similar data obtained in C and ME-lesioned rats.

Altered response of blood thyroxine level after its acute depletion by isovolemic exchange transfusion in rats with lesions in hypothalamus and thalamus.

Bilateral electrolytic lesions were made in various areas of hypothalamus or thalamus on the 6th day of a period of daily radioiodide injections (1 or 5 muCi125I-daily per animal) in male rats weighing about 350 g. Such injections were continued for another 4 days and after 2 days of intermission the blood thyroid hormone was acutely depleted by isovolemic exchange transfusion of thyroid hormone free blood cell suspension. Relative changes of plasma thyroxine level were measured with the aid of paper chromatography in small aliquots of plasma frequently taken from the animals under maintaining isovolemia by replacing the removed plasma. It was found that in animals with various bilateral electrolytic lesions in hypothalamus (suprachiasmatic and paraventricular areas) the response of blood thyroxine level after the transfusion is similar as in sham-operated controls bearing unilateral subcortical lesion or in normal animals observed previously. On the other hand, the response in animals with thalamic lesions was repeatedly found to resemble that observed previously in thyroidectomized animals. Since the response of blood thyroxine level presumably results from changes of pituitary thyrotropic activity, it is concluded that in rats with thalamic lesions the normal response of hypothalamo-pituitary-thyroid axis was prevented. The mechanism of this action, however, remains to be elucidated.