Periovulatory increase in temperature difference within the rabbit oviduct

BACKGROUND: Earlier studies demonstrated a small temperature difference between the sperm storage and fertilization sites within the oviducts of rabbits and pigs. Our aim was to reveal the time dependence of this temperature difference relative to ovulation, and to determine how this difference is generated-by temperature elevation at one of these sites or by temperature decrease at the other site. METHODS: The temperature at the sperm storage site (at the isthmus near the uterotubal junction) and at the fertilization site (the isthmic-ampullary junction) of rabbit oviducts were measured before, during, and after ovulation by two probes, connected to digital thermometers. Rectal temperature was constantly measured and served as a control for body temperature. RESULTS: The temperature difference between the fertilization site and the storage site was 0.8+/-0.2 degrees C before ovulation. This difference increased at ovulation, reaching 1.6+/-0.1 degrees C after ovulation (P<0.03). This increased difference was mainly due to temperature decrease in the sperm storage site. CONCLUSION: The temperature-difference increase within the rabbit oviduct is generated at ovulation by a reduced temperature at the sperm storage site. This temperature gradient may play a role in mammalian reproduction via sperm thermotaxis.     

Local thermal unpleasantness and discomfort prediction in the vicinity of thermoneutrality

This work emphasizes a better understanding of the origin of human thermal discomfort under heterogeneous but steady environments, in subjects in the vicinity of physiological and sensory thermoneutrality. The knowledge of skin temperatures allows a psychophysiological study aiming at linking the body thermal state (local and global) to thermal sensation (perceptive and affective judgements). By using two driving simulators, 345 subjects were exposed to different thermal environments, modulated by factors such as the air distribution in the automotive cockpit or the clothing insulation (winter or summer). This work shows that consideration of the local thermal state is essential for the evaluation of thermal comfort in the case of non-uniform environments. Our experimental conditions point out that the overall sensation of discomfort is quantitative, with local unpleasantness needing to be felt for a certain number of body surfaces. A local origin is suggested for cold discomfort, in opposition to the global characteristics of warm discomfort.     

智能化穴位温度检测仪的研制及实验研究

在经络穴位的生物物理属性中，由于皮肤温度比较灵敏，易于观察，又能及时反映该处血管的舒缩变化。作者利用铂电阻作为测温控头，用微机进行数据处理，并利用该系统进行人体皮肤温度的检测及分析。结果表明：皮肤温差点基本上是循经分布的。     

Relationship between frequency and amplitude of myocardial contractions in rats adapted to heat

After preliminary adaptation of rats to heat (for 3 h daily at 35°C for 1 month) the amplitude of contractions of the isolated papillary muscles from the left ventricle at 28°C at high frequency was higher than in control animals. This difference persisted at 36°C and disappeared at 25°C. It is postulated that adaptation to heat leaves a definite structural imprint in heart muscle cells.Laboratory of Pathophysiology of the Heart, Institute of General Pathology and Pathological Physiology, Academy of Medical Sciences of the USSR, Moscow. Institute of Physiology and Experimental Pathology of the Arid Zone, Academy of Sciences of the Turkmenian USSR, Ashkhabad. (Presented by Academician of the Academy of Medical Sciences of the USSR A. M. Chernukh.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 10, pp. 1168–1170, October, 1976.     

抗人卵巢癌×抗人CD3×抗CD28VH单链三特异抗体的胞内可溶表达、纯化及体外活性测定

目的　研究抗人卵巢癌 (ovariancarcinoma ,oc)×抗人CD3×抗CD2 8VH 单链三特异抗体(singlechaintrispecificantibody,scTsAb)在大肠杆菌中的可溶表达与纯化及纯化后产物的活性测定 ,从而为其应用于卵巢癌治疗的临床研究打下基础。方法　将已构建的scTsAb表达载体转化大肠杆菌BL2 1(DE3)Star菌株 ,采用低温 (30℃ )、低剂量IPTG(0 .2mmol L)诱导 ,进行胞内可溶表达。根据抗卵巢癌三特异抗体 (ocTsAb)等电点较高 (pI9.0 ) ,而菌体蛋白大多为酸性蛋白的特点 ,利用DEAE弱阴离子交换层析(pH8.0 )进行一步纯化 ,并利用ELISA及FACS的方法检测纯化后抗卵巢癌三特异抗体的活性。结果　(1)SDS PAGE鉴定低温诱导时可溶比例达到 5 6 %。 (2 )绝大多数菌体蛋白被DEAE层析柱吸附 ,而抗卵巢癌三特异抗体在穿透液中流出 ,SDS PAGE检测纯度达到 90 %。 (3)ELISA结果显示纯化后的抗卵巢癌三特异抗体与重组CD2 8纯抗原 ,Jurkat(CD3 )细胞膜提取抗原 ,SKOV3细胞膜提取抗原均有特异性结合。 (4 )FACS结果证明纯化后的抗卵巢癌三特异抗体与Jurkat(CD3 )活细胞、SKOV3活细胞有特异性结合。结论　低温诱导胞内可溶表达的抗人卵巢癌×抗人CD3×抗CD2 8VH 单链三特异抗体经弱阴离子交换层析一步纯化后仍保持原有免疫学活性 ,这     

Correlation-based decomposition of surface electromyograms at low contraction forces

The paper studies a surface electromyogram (SEMG) decomposition technique suitable for identification of complete motor unit (MU) firing patterns and their motor unit action potentials (MUAPs) during low-level isometric voluntary muscle contractions. The algorithm was based on a correlation matrix of measurements, assumed unsynchronised (uncorrelated) MU firings, exhibited a very low computational complexity and resolved the superimposition of MUAPs. A separation index was defined that identified the time instants of an MU's activation and was eventually used for reconstruction of a complete MU innervation pulse train. In contrast with other decomposition techniques, the proposed approach worked well also when the number of active MUs was slightly underestimated, if the MU firing patterns partly overlapped and if the measurements were noisy. The results on synthetic SEMG show 100% accuracy in the detection of innervation pulses down to a signal-to-noise ratio (SNR) of 10 dB, and 93±4.6% (mean± standard deviation) accuracy with 0 dB additive noise. In the case of real SEMG, recorded with an array of 61 electrodes from biceps brachii of five subjects at 10% maximum voluntary contraction, seven active MUs with a mean firing rate of 14.1 Hz were identified on average.     

A probabilistic approach to measure the strength of bone cell adhesion to chemically modified surfaces

Patterned surfaces with alternating regions of amino silanes [N-(2-aminoethyl)-3-aminopropyl-trimethoxysilane (EDS)] and alkyl silanes [dimethyldichlorosilane (DMS)] have been used to alter the kinetics of spatial distribution of cellsin vitro. In particular, we have previously observed the preferential spatial distribution of bone cells on the EDS regions of EDS/DMS patterned surfaces (10). In this study, we examined whether the mechanism of spatial distribution of cells on the EDS regions was adhesion mediated. Homogeneous layers of EDS and DMS were immobilized on quartz substrates and characterized by contact angle, X-ray photoelectron spectroscopy, and spectroscopic ellipsometry. The strength of bone cell attachment to the modified substrates was examined using a radial flow apparatus, within either 20 min or 2 hr of cell incubation in the presence of serum. A Weibull distribution was chosen to characterize the strength of cell-substratum adhesion. Within 20 min of cell exposure, the strength of adhesion was significantly larger on EDS and clean surfaces, compared with DMS surfaces (p<0.0001). Within 2 hr of cell incubation, there was no statistical difference between the strength of cell adhesion to EDS, DMS, and clean surfaces. The results of this study suggest that the surface chemistry mediates adhesion-based spatial cell arrangement through a layer of adsorbed serum proteins.     

Prediction of the average skin temperature in warm and hot environments

The prediction of the mean skin temperature used for the Required Sweat Rate index was criticised for not being valid in conditions with high radiation and high humidity. Based on a large database provided by 9 institutes, 1999 data points obtained using steady-state conditions, from 1399 experiments and involving 377 male subjects, were used for the development of a new prediction model. The observed mean skin temperatures ranged from 30.7 °C to 38.6 °C. Experimental conditions included air temperatures (T _a) between 20 and 55 °C, mean radiant temperatures (T _r) up to 145 °C, partial vapour pressures (P _a) from 0.2 to 5.3 kPa, air velocities (v _a) between 0.1 and 2 m/s, and metabolic rates (M) from 102 to 620 W. Rectal temperature (T _re) was included in the models to increase the accuracy of prediction. Separate models were derived for nude (clothing insulation, I_cl, ≤0.2 clo, where 1 clo=0.155 m² · °C · W⁻¹, which is equivalent to the thermal insulation of clothing necessary to maintain a resting subject in comfort in a normally ventilated room, air movement=10 cm/s, at a temperature of 21 °C and a humidity of less than 50%) and clothed (0.6 ≤ I_cl ≤ 1.0 clo) subjects using a multiple linear regression technique with re-sampling (non-parametric bootstrap). The following expressions were obtained for nude and clothed subjects, respectively: T _sk=7.19 + 0.064T _a + 0.061T _r + 0.198P _a− 0.348v _a + 0.616T _re and T _sk=12.17 + 0.020T _a + 0.044T _r + 0.194P _a − 0.253v _a + 0.0029M + 0.513T _re. For the nude and clothed subjects, 83.3% and 81.8%, respectively, of the predicted skin temperatures were within the range of ±1 °C of the observed skin temperatures. It is concluded that the proposed models for the prediction of the mean skin temperature are valid for a wide range of warm and hot ambient conditions in steady-state conditions, including those of high radiation and high humidity. Accepted: 7 February 2000     

Physical dilatation of the nostrils lowers the thermal strain of exercising humans

Increased nasal air flow during exercise was examined as a possible heat loss avenue contributing to selective brain cooling in hyperthermic humans. On 2 separate days, eight subjects [mean (SE) age, 26.4 (1.2) years] exercised on a cycle ergometer in a warm room [28 (0.2)°C; 28 (5)% relative humidity] to induce a moderate level of hyperthermia. In one session the nostrils were physically dilatated [average dilatation 1.55 (0.17) times] and in the other they were not (control). Both sessions started with a 5-min resting period; then subjects pedaled at 60 W for 5 min, 100 W for 15 min, and 150 W for 20 min. During dilatation both tympanic temperature (T _ty) and forehead skin blood flow, estimated by laser doppler velocimetry, were significantly lower than during the control exercise of 150 W. Rates of increase of (T _ty) during the 100-W exercise were the same in both conditions; however, during the 150-W exercise with dilatated nostrils (T _ty) increased at a rate significantly lower than during control [1.1 (0.3)°C·h^–1 vs 1.5 (0.4)°C·h^–1]. The change in the rate of increase of T _ty between conditions was significantly correlated to the degree of nostril dilatation (r = –0.77, P = 0.02), suggesting that the lower (T _ty) observed was due to nostril dilatation. Facial skin temperature was not significantly different between sessions. The results suggest that the nasal cavity may act as a heat exchanger in selective brain cooling of exercising humans.