Dexamethasone decreases the transmesothelial electrical resistance of the parietal and visceral pleura

The effect of dexamethasone on the transmesothelial electrical resistance (R _TM) of sheep pleura was investigated by Ussing chamber experiments. Our results show that dexamethasone decreases the R _TM of sheep pleurae, in part by stimulation of glucocorticoid receptors. This finding may be of importance in regard to the faster resolution of corticosteroid-treated pleural effusions.     

Effect of amiloride in human and sheep parietal pleura

The fluid and solute transport properties of human parietal pleura were studied and compared with sheep parietal pleura in vitro. The pleura was mounted as a planar sheet between Ussing-type chambers. The results presented are the mean values of nine different experiments. The transepithelial electrical resistance (R(TE)) of both pleurae species was measured before and after the addition of amiloride in both sides of pleura. The R(TE) for human was 25.74 +/- 1.23 Ohm x cm(2), while for the sheep it was 38.18 +/- 0.83 Ohm x cm(2). The addition of amiloride to the serosal bathing solution increased the R(TE) of human pleura to 30.48 +/- 1.01 Ohm x cm(2) and sheep pleura to 40.32 +/- 0.82 Ohm x cm(2), while amiloride had no effect on the basolateral side. From the above, it is strongly suggested that the human pleura seems to be more leaky than sheep pleura. Although the R(TE) was increased in both pleurae, the elevation in human pleura was significantly higher, thus results from experiments in sheep pleura could only partly be extrapolated in human pleura.     

Effect of cadmium on thyroid function in sheep

The objective of this experiment was to determine the effect of long-term low-dose administration of cadmium on thyroid function in sheep. In this experiment, ten healthy Iranian male sheep, aged about 1 year old, were randomly allocated into two equal groups of control (n = 5) and experiment (n = 5). Both groups were kept under the same conditions of food and environment. Treatment group received cadmium chloride (1 mg/kg/day) orally for 8 weeks. Blood sampling of two groups was done on days 0, 14, 28, 42, 56, and 70 every morning (8 to 9 a.m.). The function of the thyroid was evaluated by measuring the levels of serum thyroid hormones T3, T4, FT3, FT4, and TSH. The hepatic function in both groups was evaluated by measuring hepatic enzyme activities including alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ glutamyl transferase (GGT), and total bilirubin (TBIL). Serum levels of T3, T4, FT3, FT4, and TSH significantly decreased in cadmium-treated sheep when compared to control group (p < 0.05). Serum enzyme activities of ALT, AST, GGT, and TBIL in Cd-treated sheep were significantly increased in comparison with control group (p < 0.05). Our findings suggest that Cd-exposed sheep can be at a risk of low thyroid function.     

Effect of manganese on thyroid function in sheep

Ten healthy adult male sheep aged about 1 year old were randomly allocated into two equal groups of control (no treatment group, n = 5) and experiment (n = 5). The two groups were kept under the same conditions of food and environment. Sheep of experimental group received MnSO₄, H₂O (5 mg/kg/day, SC) from day 0 for 8 weeks. Blood sampling of the two groups were done on days 0, 14, 28, 42, 56, and 70 at 11 a.m. Serum T4, T3, FT3, FT4, TSH, manganese, creatinine, and blood urea nitrogen concentrations were measured. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and serum alkaline phosphatase (ALP) activities were estimated by conventional methods. Serum and urine GGT activities were also measured. Urine samples were tested by urine dipstick analysis. Results indicated that serum manganese concentration was increased significantly on days 14, 28, 42, 56, and 70 of manganese administration (p < 0.05). The changes in serum enzyme activities ALP, GGT, AST, ALT, and urea and creatinine concentrations during these days were not significant. Changes of urine GGT activity were not significant. Serum TSH, FT3, FT4, T3, and T4 concentrations decreased differently on days 14, 28, 42, and 56 (p < 0.05). Urinalysis by urine dipstick analysis was normal.     

小白鼠胸膜间皮的扫描电镜观察

目的　观察小白鼠脏、壁胸膜间皮细胞在扫描电镜下的结构以及两者在结构上的异同。方法　用扫描电镜对比观察 5只小白鼠的脏胸膜及各部壁胸膜的结构。结果　脏、壁胸膜间皮细胞表面有大量粗、细微绒毛 ,较多的火山口样凹陷及一些细胞间孔 ;脏胸膜间皮表面粗微绒毛密集且分支多 ,分支内有大量串珠样颗粒 ,多见具有芽状或颗粒状微绒毛的幼稚间皮细胞 ;壁胸膜间皮表面粗微绒毛稀疏 ,细微绒毛密集 ,多见微绒毛退化消失且有即将与间皮分离的衰老细胞、火山口样凹陷及细胞间孔。结论　脏胸膜间皮可能具有较强分泌功能 ,而壁胸膜间皮吸收功能较强     

Effect of phentolamine on the relationship between O2 consumption and delivery in sheep

Summary The oxygen flux challenge test (OFT) has recently been used in critically ill patients as a dynamic test for assessment of the response in oxygen consumption VO₂ to an increase in O₂ delivery (QO₂). Such a test may indicate whether a patient demonstrates delivery-dependent VO₂. However, the increase in whole body VO₂ following an increase of QO₂ might be due to the agents used for the OFT. In this study, we examined the possibility of obtaining false positive OFT with an -adrenergic antagonist. Five normothermic thiopentone-anaesthetised and mechanically-ventilated (inspired O₂ fraction, 0.3; expired CO₂ fraction, 0.045–0.055) adult sheep (25–31 kg) were investigated. The QO₂ was increased in a stepwise fashion from 200 to 850 ml·min^–1 by vasodilatation with intravenous infusion of phentolamine. The VO₂ was calculated at each step from the product of arteriovenous O₂ content difference (CO_2,a-v) and cardiac output (Q_c), the latter being continuously measured with a transit-time ultrasonic flow probe placed around the main pulmonary artery. The VO₂ (y) was linearly related to QO₂ (x), y=0.034 (SD 0.024) x+29.3 (SD 3.9). The relationship between Q_c (y) and CO_2,a-v (x) was y=4.6x ^–1.12 (n=69; r ²=0.75; P=NS compared to the expected relationship for isoconsumption conditions, i.e. where Q_c=VO₂·(CO_2,a-v)^–1. Our data suggested that under stable conditions, an infusion of phentolamine did not sufficiently alter the relationship between Q_c and CO_2,a-v to invalidate its use for OFT in normal sheep.Preliminary reports of this work were presented at the annual meeting of the Federation of the American Societies for Experimental Biology, New Orleans, March 21–24, 1989     

Effect of three decellularisation protocols on the mechanical behaviour and structural properties of sheep aortic valve conduits

PurposeTo determine the best method for decellularisation of aortic valve conduits (AVCs) that efficiently removes the cells while preserving the extracellular matrix (ECM) by examining the valvular and conduit sections separately.Material/methodsSheep AVCs were decellularised by using three different protocols: detergent-based (1% SDS + 1% SDC), detergent and enzyme-based (Triton + EDTA + RNase and DNase), and enzyme-based (Trypsin + RNase and DNase) methods. The efficacy of the decellularisation methods to completely remove the cells while preserving the ECM was evaluated by histological evaluation, scanning electron microscopy (SEM), hydroxyproline analysis, tensile test, and DAPI staining.ResultsThe detergent-based method completely removed the cells and left the ECM and collagen content in the valve and conduit sections relatively well preserved. The detergent and enzyme-based protocol did not completely remove the cells, but left the collagen content in both sections well preserved. ECM deterioration was observed in the aortic valves (AVs), but the ultrastructure of the conduits was well preserved, with no media distortion. The enzyme-based protocol removed the cells relatively well; however, mild structural distortion and poor collagen content was observed in the AVs. Incomplete cell removal (better than that observed with the detergent and enzyme-based protocol), poor collagen preservation, and mild structural distortion were observed in conduits treated with the enzyme-based method.ConclusionsThe results suggested that the detergent-based methods are the most effective protocols for cell removal and ECM preservation of AVCs. The AVCs treated with this detergent-based method may be excellent scaffolds for recellularisation.     

Neurochemical properties of the middle cervical ganglion in the sheep

The neurochemical properties of the ovine middle cervical ganglion (MCG) were studied using antibodies raised against tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DbetaH), neuropeptide Y (NPY), substance P (SP), calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP) and galanin (GAL). Double-labelling immunocytochemistry revealed that the vast majority (95.5 +/- 0.8%) of postganglionic sympathetic MCG neurons expressed simultaneously both catecholamine-synthesizing enzymes (neurons were TH/DbetaH-positive). A large population of noradrenergic neurons exhibited immunoreactivity (IR) to NPY (62.2 +/- 2.2%), but single NPY-positive perikarya-lacking noradrenergic markers were also observed (2.0 +/- 0.3%). None of the examined MCG neuronal somata contained SP, CGRP, GAL or VIP. A moderate number of noradrenergic nerve fibres located amongst neuronal cell bodies was also found. In small number of these terminals the presence of NPYor GAL (but not CGRP or VIP) was detected. The ovine MCG was numerously innervated with SP-immunoreactive nerve fibres which sometimes formed basket-like formations around postganglionic neurons. The MCG exhibited a sparse CGRP-immunoreactive innervation and lacked VIP-positive nerve terminals. In many aspects the chemical coding of MCG postganglionic neurons and nerve terminals resembles that found in other mammalian cervico-thoracic paravertebral ganglia, but some important species-dependent differences exist. The functional implications of these differences remain to be elucidated.     

Effect of combat stress and capitulation stress on resistance of heart muscle to excess calcium

Research Institute of General Pathology and Pathological Physiology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR G. N. Kryzhanovskii.) Transiated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 109, No. 4, pp. 325–327, April, 1990.     

β-肾上腺素能刺激促进离体小鼠心脏缺氧/复氧诱导的细胞凋亡

目的：观察β-肾上腺素能刺激与缺氧/复氧损伤对离体小鼠心脏细胞凋亡的影响。 方法： 逆行灌注离体小鼠心脏，观察不同剂量异丙基肾上腺素（Iso）和不同时间缺氧/复氧心肌细胞凋亡率的变化，并观察β1-肾上腺素能受体阻滞剂、caspase-拮抗剂、Bcl-2对其凋亡率的影响，以TUNEL法检测心肌细胞凋亡率。 结果： 单独Iso未引起心肌细胞凋亡率的变化，但可增加缺氧/复氧所诱导的细胞凋亡率；Bcl-2转基因鼠细胞凋亡率明显低于正常小鼠；β1-受体拮抗剂（美托洛尔）及caspase -拮抗剂（zVAD.fmk）可明显抑制Iso和缺氧/复氧所致细胞凋亡。 结论： β-肾上腺素能受体激动剂可促使缺氧/复氧所诱导心肌细胞凋亡，其诱导凋亡的作用主要通过β1-受体介导，β1-受体拮抗剂可抑制二者共同作用所诱导心肌细胞凋亡。     

高原（3780米）和平原绵羊内毒素急性肺损伤的比较观察

本研究比较观察了高原和平原绵羊内毒素所致的急性肺损伤。用１２只绵羊（高原组５只，平原组７只），制备肺淋巴瘘２￣３天后，静脉内注射１．５μｇ／ｋｇ大肠杆菌内毒素致伤。结果：高原组肺动脉压（Ｐｐａ）升高幅度大于平原组，持续时间也较长；肺淋巴流量（ＱＬ）高原组增加了６．２倍，平原组增加了４．４倍（Ｐ〈０．０５）；肺淋巴蛋白清除率（ＰＣ）高原组增加了８．２倍，平原组增加了４．７倍（Ｐ〈０．０５）；肺血管通     

The hemagglutinin of Staphylococcus saprophyticus binds to a protein receptor on sheep erythrocytes

Staphylococcus saprophyticus, an important cause of urinary tract infections, produces two major surface proteins, the S. saprophyticus surface-associated protein (Ssp) and the hemagglutinin, which mediates fibronectin binding and also functions as the major adhesin of the organism. The hemagglutinating and fibronectin binding functions probably reside on different parts of the molecule. To identify a receptor on eukaryotic cells, binding and inhibition studies with acidic and neutral glycosphingolipids, carbohydrates, and proteins of sheep erythrocyte membranes were conducted. S. saprophyticus did not bind to any glycosphingolipid and no inhibition was observed when hemagglutination assays were done in the presence of carbohydrates or fibronectin. Neither treatment of erythrocytes with galactose oxidase or neuraminidase and galactose oxidase nor mild periodate oxidation of erythrocytes reduced hemagglutination. However, proteinase-treated erythrocytes were no longer agglutinated. Similarly, untreated erythrocyte membranes inhibited hemagglutination, whereas proteinase-treated membranes did not. In addition, only hemagglutinating strains bound to 60- and 21-kDa sheep erythrocyte membrane proteins on ligand blots, and these proteins inhibited hemagglutination. Our data indicate that, in contrast to many other hemagglutinins, the receptor on sheep erythrocytes for S. saprophyticus is a protein. Received: 27 March 1997     

Effect of geomagnetic activity on rat resistance to hypoxia

Resistance to acute hypoxia in rats was evaluated by the life span after elevation to an altitude of 11,500 m at 13.00-21.00 (local time) in different seasons of one year. Geomagnetic activity was evaluated using local K index for Moscow and planetary Kp index. Total 24-h geomagnetic activity had a great impact on the life span of rats. The effects of local and planetary geomagnetic activities coincided in about 70% cases. An increase in geomagnetic activity was responsible for prolongation, decrease (2-3 times more often than prolongation), and phase changes in the life span of rats, which were the most pronounced in the case of medium geomagnetic activity, during the second half of the year (in summer and particularly in autumn), in the middle and end of the day, in rats with low resistance to hypoxia.     

Effect of abolition of hybrid resistance on survival of radiation chimeras

The effect of abolition of hybrid resistance by injection of lymphocytes on survival of lethally irradiated mice protected by transplantation of semiallogeneic bone marrow was studied. Injection of C57BL lymphocytes into (C57BL×CBA)F₁ recipients 1 day before irradiation and transplantation of bone marrow of the same genotype (C57BL) increased the survival rate of the chimeras compared with untreated recipients, whereas the same treatment, given 7 days before irradiation, reduced the survival rate of the chimeras. Injection of lymphocytes of the parental line had a negligible action on the radioresistance both of the hematopoietic stem cells (as shown by the endocolonization test) and on the body as a whole (as shown by the 30-day survival test) of the F₁ hybrid; it is accordingly concluded that differences in the effectiveness of the splenocytes when injected at different times before irradiation cannot be explained by changes in radioresistance.Laboratory of Bone Marrow Culture and Transplantation, Central Institute of Hematology and Blood Transfusion, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR N. A. Fedorv.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 1, pp. 42–44, January, 1977.