Primary malignant melanoma: a rare cause of mediastinal mass

A case of primary malignant melanoma in the mediastinum presenting as recurrent laryngeal nerve palsy is reported. Tissue biopsy at mediastinotomy yielded a diagnosis of malignant melanoma. The mass was fixed to the left aspect of the trachea and to the upper border of the left main bronchus and could not be removed surgically. Further extensive clinical and radiological investigations revealed no evidence of tumor elsewhere in the body.     

Pterygium excision with free conjunctival autograft (FCG) versus postoperative strontium 90 (90Sr) beta-irradiation. A prospective study

In a prospective study the results of a pterygium excision in 54 patients (57 eyes) who underwent a superficial free conjunctival autograft (FCG) were compared to those of patients who were treated with postoperative90Sr-irradiation. In 51 cases the minimum follow-up was six months, the maximum follow-up seven years. We divided the study up into a randomized part and an open part. In the randomized part, surgery of a primary pterygium was performed in 25 eyes, of which 16 were treated with a FCG and compared with 9 eyes with primary pterygium surgery and postoperative90Sr beta-irradiation. In the same period 16eyes were treated because of a recurrent pterygium: 8 with FCG and 8 with90Sr-irradiation. In the open part of the study16 eyes with primary pterygium were successively treated with FCG alone. The results showed in the randomized, as well as in the open study on primary surgery with a minimum follow-up of six month, one recurrence in each of the FCG-groups (2 out of 31 eyes =6.4%), and no recurrences in the 90Sr-group(0%). In the randomized group of patients treated for a recurrent pterygium one recurrence developed in the FCG group (1 out of 8 eyes =12.5%) and one in the 90Sr-group (1 out of 7 =14.6%). Analysis of other clinical parameters showed that postoperative treatment with corticosteroids, nonsteroidal anti-inflammatory drugs, and artificial tears was necessary for a longer period in the FCG group than in the90Sr-group. This revised version was published online in August 2006 with corrections to the Cover Date.     

Non-invasive temperature imaging of muscles with magnetic resonance imaging using spin-echo sequences

The application of spin-echo magnetic resonance imaging sequences on non-invasive temperature imaging for temperature mapping of human limbs is investigated. In an in vitro expriment performed on a meat sample, the equilibrium magnetisation P and the spin-lattice relaxation time T₁ are calculated from the values for the repetition time TR and the signal intensities obtained by a spin-echo sequence at different tissue temperatures tures as measured by a fibre-optic probe. T₁ is linearly correlated to the tissue temperature, and P is linearly correlated to the reciprocal value of the absolute temperature. Both effects, taken together, lead to a non-linear dependency of the signal intensity on temperature. Therefore a TR leading to maximum temperature dependency of the signal intensity is calculated and used in the futher experiments. In the in vivo experiments, the lower legs of two volunteers are cooled from outside. Images are acquired with a spin-echo sequence (1.5T, TR=1200 ms, TE=10 ms). A rise in signal intensity in the muscle with falling skin temperature is observed, particularly in more peripheral muscle layers. This study shows that spin-echo sequences can be used to monitor temperature changes and temperature differences in living muscle tissue.     

Maximal and submaximal oxygen uptake during running: how should body mass be accounted for?

Oxygen uptake during running, i.e., the running economy, is an important factor in determining running performance in endurance events. The relation to performance is particularly strong when the aerobic running capacity is calculated, i.e., when running economy is related to the maximal oxygen uptake. There is considerable interindividual variation in running economy, and the reason for this is only partly understood. To some extent, this may be due to the way in which the oxygen uptake during running is usually expressed. This may expecially be true when subjects with different or changing body masses are compared. Several lines of evidence, including earlier animal studies as well as more recent human studies, favor the expression of submaximal and maximal oxygen uptake during running in terms of ml · kg^−0.75· min⁻¹ rather than as ml · kg⁻¹· min^−1.     

烟叶硒蛋白对人红细胞的辐射溶血及自由基的作用

本文观察了烟叶硒蛋白对人红细胞６０Ｃｏγ照射溶血的影响，发现硒蛋白对红细胞γ照射溶血有极好的预防效果，同时采用电子自旋共振法（ＥＳＲ）发现硒蛋白对羟自由基有明显的清除作用，并具有明显的剂量－效应关系，在相同浓度下具有优于亚硒酸钠及不含硒的同类蛋白的作用，提示硒蛋白有更好的生物效应。     

大鼠气管上皮细胞体内—体外转化模型的研究

本研究建立了大鼠气管上皮细胞体内－体外转化模型，大鼠气管内滴注苯并芘，三天后处死大鼠，消化气管上皮细胞，接种于无血清完全培养基。细胞形成集落后，换为选择培养基继续培养五周，统计转化率。结果显示，２５ｍｇ／ｋｇ和５０ｍｇ／ｋｇ的苯并芘可诱导大鼠气管上皮细胞转化及微核增加，用同样方法研究了煤焦沥青提取物，结果表明，剂量为８ｍｇ／ｋｇ和２５ｍｇ／ｋｇ的煤焦沥青提取物能明显诱导大鼠气管上皮细胞转化。     

Effects of androgen treatment in impotent men with normal and low levels of free testosterone

The relation between sexual function and serum free testosterone (fT) levels, which represent the active fraction of circulating testosterone, was evaluated. Two groups of impotent male subjects with mild hypogonadism were treated with oral testosterone undecanoate (TU); these men presented with tT/luteinizing hormone (LH) ratio and tT levels at the lower limits of normal. The first group had serum fT below 6.6 ng/ml, considered the lower normal value, according to our laboratory method, whereas the second group had normal fT limits. Administration of TU improved sexual function only in impotent men with low fT levels, but not in subjects with normal fT levels, even though the tT levels and the tT/LH ratio of the two groups were not significantly different. The results of our study suggest the presence of a minimun serum fT threshold, lying near the lower normal range, which determines the male sexual function. Moreover, serum fT levels were a more sensitive index than tT for identifying impotent men who can be successfully treated with androgens.     

从自由基生物学角度评价鸡肉质量的实验研究

本文把外观健康和非健康的活鸡各20只分成两组,宰后测其肝、腿肌中超氧化物歧化酶(SOD)含量和脂质过氧化产物丙二醛(MDA)水平,发现两组中上述指标值差异显著(P<0.050 ;同时对两组实验鸡胴体在宰后4小时做了感官鉴别,也判断出其品质存在差异。提示体内SOD活性和MDA水平可以反映鸡肉质量,比感官鉴别更具敏感性,同时也可以反映宰前鸡的健康状况。     

Ethanol regulated preference in rats

A series of experiments evaluated the determinants of preference for mixtures of ethanol plus sucrose relative to sucrose in rats. One dipper served 10% ethanol mixed with 10% sucrose, and the second dipper served 10% sucrose. Lever presses operated each dipper according to a variable-interval 5-s schedule. In three experiments the subjects were given pre-session meals of sucrose (2.5–20 ml) or sucrose (20 ml) plus chow (5 or 10 g). Pre-session meals decreased responding maintained by sucrose but not responding maintained by ethanol mixture. In two experiments body weight was varied from 85% to 125% of the initial free-feeding values. Increases in body weight, like pre-session meals, decreased responding reinforced by sucrose, but typically did not decrease responding reinforced by ethanol mixture. Throughout most of the study, ethanol consumption remained at about 1.25 ml per half hour session (3–4 g/kg per 30 min). For example, pre-session access to ethanol mixture decreased within-session ethanol consumption, but total consumption, counting both sources, remained about 1.25 ml/session. The within-session patterns of responding also differed. Responding reinforced by ethanol mix decreased as a function of ethanol consumption, whereas responding reinforced by sucrose was relatively constant throughout the session. The simplest explanation of the results is that ethanol's pharmacological consequences regulated preference.     

High resolution electron paramagnetic resonance imaging of biological samples with a single line paramagnetic label

The application of electron paramagnetic resonance imaging (EPRI) to obtain information from biological samples has been limited by the lack of ideal single line radical labels. The commonly used nitroxides exhibit multiple lines causing either hyperfine-based limitations in the maximum obtainable image resolution or hyperfine-based artifacts in the reconstructed image. The use of a novel single-line triarylmethyl paramagnetic label that enables marked enhancement in image quality and resolution is reported. This label exhibits a single line EPR spectrum that is sharp (linewidth ～60 mG in the absence of oxygen) and relatively stable in tissues. The potential of this label in enabling high resolution EPR imaging of biological samples was demonstrated in a series of phantoms and isolated biological organs such as the rat kidney. The images demonstrate that resolutions better than 100 μm could be obtained at L-band on samples of up to 20 mm in size.