三碘甲状腺原氨酸对缺血再灌注损伤后未成熟心肌细胞中Bax、Bcl-2的影响

目的通过三碘甲状腺原氨酸对缺血再灌注损伤后未成熟心肌细胞中Bax、Bcl-2表达的影响,探讨其作用机制。方法培养原代乳鼠未成熟心肌细胞,通过缺氧复氧建立乳鼠心肌细胞缺血再灌注模型。于缺氧复氧前期给予三碘甲状腺原氨酸处理,通过聚合酶链反应仪检测三碘甲状腺原氨酸干预后心肌细胞的Bax mRNA和Bcl-2 mRNA表达情况。结果缺氧复氧前短期给予三碘甲状腺原氨酸可下调乳鼠未成熟心肌细胞Bax的表达,上调Bcl-2的表达,减少心肌细胞凋亡。结论三碘甲状腺原氨酸可以提高未成熟心肌抗缺血再灌注损伤的能力,而对心肌细胞凋亡这种保护作用与心肌细胞Bcl-2和Bax的表达相关。     

江苏省某戒毒所男性吸毒人员甲状腺激素水平及影响因素研究

目的 了解吸毒人群促甲状腺激素（TSH）、三碘甲状腺原氨酸（T3）、甲状腺素（T4）、游离三碘甲状腺原氨酸（FT3）以及游离甲状腺素（FT4）的异常情况及影响因素。方法 2018年6－8月于江苏省某戒毒所招募788名男性吸毒人员进行一对一的问卷调查并采集静脉血进行甲状腺功能5项激素项目的检测。结果 调查结果显示,江苏省某戒毒所男性戒毒人员的血清T3、T4、FT3、FT4以及TSH的异常率分别为4.57%、1.27%、0.51%、0.38%和0.89%。HCV感染是该人群发生T3异常的影响因素（OR=8.52,95% CI：2.36～30.74,P=0.001）,且血清T3（P<0.001）和T4（P=0.048）水平随着HCV病毒载量的升高而升高。结论 HCV感染是男性吸毒人员发生血清T3水平异常的影响因素。因此,在对吸毒人群进行健康教育时应增加甲状腺相关的知识,对感染HCV的男性吸毒人员还应加强甲状腺功能的监测。     

长沙地区394例正常人血清γT_3值的测定

本文测定394例自20～81岁之健康人血清rT_3 值。血清rT_3 平均值为 40.63±4.45ng/dL。男性较女性高(p<0.05)。60岁以下的rT_3 值明显地高于老年组(p<0.01)。     

Ultrastructure changes associated with brain death in the human donor heart

Electromicroscopic examinations were carried out on 30 myocardial biopsies taken from 22 human donor hearts immediately after excision (prestorage) or immediately before transplantation (post-storage). All electron micrographs were independently examined by two morphologists. Eleven structures were examined in each micrograph, and each structure was scored according to the degree of injury. A good interobserver correlation was obtained in 84 % of the structures scored. In the prestorage left ventricular biopsies (n = 11), approximately 20 %–25 % showed moderate to severe ultrastructural injury. The ultrastructural injury observed in the poststorage left ventricular biopsies (n = 15) was no different from that in the prestorage group, particularly injury to the sarcomere and mitochondria. A similar degree and pattern of injury was seen in the right ventricle (n = 4). There was no evidence that an ischemic storage period of less than 6 h increased the degree of injury seen. However, there was a higher incidence of moderate to severe injury in those hearts excised from donors initially dependent on high inotropic support.     

Serum triiodothyronine,bone turnover,and bone mass changes in euthyroid pre- and postmenopausal women

Summary Hyperthyroidism and thyroid hormone substitutive therapy with serum iT₃ in the normal range of values are known to lead to increased bone remodeling and loss of bone mass. We looked for a relationship between serum iT₃ and bone metabolic or bone mass parameters in 402 euthyroid women aged 44–60. In a group of 93 premenopausal women, a group of 309 postmenopausal women, and a group of 118 untreated postmenopausal women, serum iT₃ was higher in the women classified as having “high” bone turnover according to both alkaline phosphatases and hydroxyprolinuria values. In postmenopausal women, serum iT₃ corrected for thyroid binding globulin (TBG) (T_3c) was higher in those receiving no estrogen replacement therapy. In a longitudinal study (n=131), the rate of changes in lumbar bone mineral content was associated with changes in T_3c. A less favorable bone mass evolution was associated with an increase in serum T_3c, and inversely. Data suggest that the relationship of iT₃/bone metabolism is direct and not merely the consequence of estrogen induced changes in both iT₃ and bone metabolism. iT₃ should be explored at the bone cellular level as a possible mediator in bone metabolic changes occurring in menopause and many other clinical situations.     

Follow-up of newborns with elevated screening T4 concentrations

OBJECTIVE: To determine the type and incidence of hyperthyroxinemic disorders detected by follow-up of infants with elevated screening total T4 (TT4) values. STUDY DESIGN: Infants born in Oregon with a screening TT4 measurement >3 SD above the mean were offered enrollment. Serum TT4, free T4, total T3, free T3, and thyroid-stimulating hormone concentrations were measured in study infants and their mothers. RESULTS: Over a 20-month period, 101 infants (51 boys) and their mothers enrolled in the study (of 241 eligible infants), from a total screening population of 80,884; 17 infants were identified with persistent hyperthyroxinemia (TT4 >16 microg/dL). Ten had thyroxine-binding globulin excess (1:8088), 5 had evidence for increased T4 binding but not thyroxine-binding globulin excess (1:16,177), and 2 had findings compatible with thyroid hormone resistance (1:40,442); the other 84 infants had transient hyperthyroxinemia. Sequence analysis revealed a point mutation in the thyroid hormone receptor-beta gene in one infant with thyroid hormone resistance; no mutation was identified in the other infant. CONCLUSIONS: Although neonatal Graves' disease occurs in approximately 1 in 25,000 newborn infants, we did not detect any case among 80,884 infants, most likely because their mothers were receiving antithyroid drugs. Although the other hyperthyroxinemic disorders in the aggregate occur frequently (1:4758) and may benefit from detection, in general they do not require treatment.     

Kinetics of triiodothyronine action on Na−K-ATPase in single segments of rabbit nephron

This study was initiated to define the dose- and time-dependence of triiodothyronine (T₃) action on Na–K-ATPase in single microdissected nephron segments. For this purpose, the activity and the number of catalytic sites of Na–K-ATPase, as determined by the specific binding of³H-ouabain, were measured following a single injection of T₃ to rabbits thyroidectomized since 8–12 days. Triiodothyronine restored both the activity and the number of catalytic sites of Na–K-ATPase in a dose-dependent manner in all nephron segments were the enzyme was decreased following thyroidectomy, i.e., the proximal and the collecting tubule. At a dose of 50 g/kg bw, T₃ restored Na–K-ATPase activity and³H-ouabain binding with the same kinetics. However, the kinetics depended on the nephron segments: in the proximal tubule, Na–K-ATPase stimualtion occurred after a 12 h period of latency and was completed within 24 h whereas in the collecting tubule, the stimulation was biphasic with a first increase within the first 3 h and a second increase concomitantly to that observed in the proximal tubule. These results indicate that thyroid hormones regulate Na–K-ATPase activity by altering the number of catalytic sites of the enzyme. This control depends on two different mechanisms which differ by their timedependence.     

Hormonal changes in serum in young men during prolonged physical strain

Summary The endocrine response to severe physical strain including lack of sleep has been investigated in army personnel during a combat course of 5 days' duration. The thyroxine (T₄) concentration in serum increased during the first 24 h, and then declined at a rate corresponding to a halflife of 7.6 days and on day 6 reached the lowest level, 55 ng/ml. Triiodothyronine (T₃) displayed a similar pattern, although an increase during the first 24 h could not be demonstrated. Within 48 h after the course T₄ had returned to normal, whereas the serum level of T₃ was significantly below the level before the course (p<0.05). The serum level of TSH was suppressed during the course.The serum level of prolactin was significantly suppressed and growth hormone was markedly elevated during the course with a significant negative correlation (r=–0.6) between the two. In agreement with a previous report, there was a rapid and sustained suppression of the serum level of testosterone to a mean level of 1.1 ng/ml on day 5.Short periods of sleep (3–6 h) were shown to be effective in reversing the changes described in this paper, especially for growth hormone, prolactin, and testosterone.This study represents a part of a research programme by the Stress Research Group of the Norwegian Joint Medical Services     

Humoral and neurohormonal aspects of blood pressure regulation: Focus on angiotensin

Summary TSH, T₃ and T₄ response to stimulation with thyrotropin releasing hormone (TRH) has been investigated in 24 young healthy adults after intravenous injection and in 25 young healthy adults upon oral application of 40 mg of TRH. After intravenous injection the TSH concentration raises from a mean of 1.6 to a mean maximum of 11.7µU/ml. A statistically significant sex difference could not be found. T₃ shows a statistically significant increase which is however too small to be of diagnostic value in an individual test.After oral stimulation with 40 mg of TRH, TSH rises to a slightly higher maximum of 13.2 µU/ml after 3 h. The T₃ increase from 1.5 to 2.19 ng/ml is significant and considerably higher than after intravenous stimulation. The thyroxin increase is statistically significant.The present results compare well with previously published data for intravenous stimulation. The oral route of TRH application has not yet been widely used and the present series establishes the normal response in young healthy adults.Repetitive stimulation with three times 40 mg of TRH leads to a decrease in TSH stimulation which reaches 5.8 µU/ml 3 h after the third dose. This is in contrast to a comparable increase in plasma T₃.     

Effect of triiodothyronine on system A amino acid transport in cells of rat submandibular gland

The effect ofL-3,5,3-triiodothyronine (T₃) on -aminoisobutyric acid (AIB) transport in isolated cell suspensions of rat submandibular gland was investigated. The uptake of ATB by these cells appeared to require extracellular Na⁺ and was inhibited by ouabain (10^–3 M). Cell suspensions from thyroidectomized rats which have been given three successive doses of T₃ on alternate days (50 g/100 g BW) showed a significant increase in AIB uptake compared with cells isolated from thyroidectomized rats treated with diluent. Efflux of AIB from the cell suspension was not affected by T₃. There was no significant changes in AIB uptake 12 h after a single injection of T₃ (50 g/100 g BW). However, there was a significant 49% and 65% increase in AIB net uptake at 24 and 48 h, respectively, after T₃ treatment. Under similar conditions, the cell suspension showed a 48% increase in NaK-ATPase activity at 12 h and to a peak of 61% at 24 h. Therefore, changes in NaK-ATPase activity preceded the changes in AIB net uptake upon treatment with T₃, implying that AIB uptake is probably mediated, at least in part, by the activity of NaK-ATPase.Abbreviations AIB -Aminoisobutyric acid - HBBS Hank's buffer salt solution - T₃ triiodothyronine This study was supported by NIH grant (AM 28590) and USUHS grant CO 7623