糖尿病大鼠视网膜微血管的重建及某些药物对其的影响

目的：研究糖尿病大鼠视网膜微血管的重建。方法：用链脲佐菌素（ＳＴＺ）诱导ＳＤ大鼠建立糖尿病动物模型,运用视网膜消化铺片和图像分析方法观测糖尿病大鼠视网膜微血管的重建,及非酶糖化抑制剂和活血化瘀中药对其重建的影响。结果：在８周时毛细血管宽度即有显著性变化（Ｐ〈０．０５）,非酶糖化抑制剂和活血化瘀中药治疗组在８～１２周后与糖尿病组有显著性差异（Ｐ〈０．０５）。结论：（１）糖尿病促进了视网膜微血管的形态     

Effect of prenatal tetrandrine therapy on pulmonary vascular structur al remodeling in the nitrofen-induced CDH rat model

Ｃｏｎｇｅｎｉｔａｌｄｉａｐｈｒａｇｍａｔｉｃｈｅｒｎｉａ (ＣＤＨ)ｒｅｓｕｌｔｓｆｒｏｍｉｎｃｏｍｐｌｅｔｅｄｅｖｅｌｏｐｍｅｎｔｏｆｔｈｅｄｉａｐｈｒａｇｍｉｎｕｔｅｒｏｗｉｔｈｈｅｒｎｉａｔｉｏｎｏｆａｂｄｏｍｉｎａｌｖｉｓｃｅｒａｉｎｔｏｔｈｅｔｈｏｒａｘ Ｓｕｒｇｉｃａｌｒｅｐａｉｒｏｆｔｈｅｈｅｒｎｉａ ,ａｌｔｈｏｕｇｈｎｏｔａｌｗａｙｓｒｏｕｔｉｎｅ ,ｉｓｒｅｌａｔｉｖｅｌｙｕｎｅｖｅｎｔｆｕｌ Ｈｏｗｅｖｅｒ,ｔｈｅｍｏｒｔａｌｉｔｙｒｅｐｏｒｔｅｄｆｏｒｇｒｏｕｐｓｏｆｔｈｏｓｅｈ…     

血管内放射抑制猪冠状动脉球囊损伤后血管重塑的机制

目的：探讨血管内放射对冠状动脉内介入治疗后血管重塑的抑制作用;方法：通过小型猪冠状动脉球囊扩张术后再狭窄动物模型,采用形态学,组织学方法和α－平滑肌肌动蛋白免疫组织化学染色方法,观察了％１９２Ｉｒ血管内放射治疗对血管重塑的影响。结果：血管内放射治疗后分别显著增加了球囊扩张术后３０ｄ血中长、血管腔周长的管腔面积,血管内放射显著减少了术后３０ｄ外膜α－ＳＭＡ阳性细胞及外膜纤维化。结论：血管内放射治疗可     

选择性PTCA逆转左室重构疗效观察

观察经皮冠脉腔内成形术能否逆转冠心病患的左室重,方法以二维超心动图测量１５例成功实施ＰＴＣＡ的左室收缩功能围术期演变,结果ＬＶＲＭ的ＣＨＤ患术后左室收缩末溶积首先缩小,随后ＬＶＥＳＶ及左室舒张末容积均缩小显;而无ＬＶＲＭ,术后ＬＶＥＳＶ及ＬＶＥＤＶ均无变化。     

Analysis of a tension/compression skeletal system: Possible strain-specific differences in the hierarchical organization of bone

Background: Examination of a simple skeletal cantilevered beam-like bone (artiodactyl calcaneus) suggests that regional differences in strain magnitude and mode (tension vs. compression) reflect regional adaptation in the structural/material organization of bone. The artiodactyl (e.g., sheep and deer) calcaneus has a predominant loading condition typified by the unambiguous presence of prevailing compressive and tensile strains on opposite cortices. Bone habitually loaded in bending may accommodate regional disparities in loading conditions through modifications of various aspects of its organization. These include overall bone build (gross size and shape), cross-sectional shape, cortical thickness, and mineral content. Methods & Results: Cross-sections taken along the calcaneal body exhibited cranial-caudal elongation with the compression (cranial) cortex thicker than the tension cortex (P < 0.01). Mineral content (ash fraction) was significantly greater in the compression cortex (P < 0.01), averaging 6.6% greater than in the tension cortex. Strong positive correlations were found between mineral content and section location in both the tension (r² = 0.955) and compression (r² = 0.812) cortices. These correlations may reflect functional adaptations to the linear increases in stress that are known to occur in the distal-to-proximal direction in simple, unidirectionally loaded cantilevered beams. According to engineering principles, the roughly triangular transverse cross-sectional geometries and thicker compression cortex are features consistent with a short cantilevered structure designed to resist unidirectional bending. Conclusions: Known differences in mechanical properties of bone in tension vs. compression suggest that these regional differences in cortical thickness and mineralization may be related to differences in strain mode. These structural/material dissimilarities, however, may be related to regional variations in strain magnitude, since bending and axially directed stresses in a simple cantilevered structure produce greater strain magnitudes in the compression domain. It is possible that the superimposed habitual strain magnitudes enhance strain-mode-specific adaptive responses. We hypothesize that these structural/material differences reflect the capacity of bone to process local information and produce a regionally heterogeneous organization that is appropriate for prevailing loading conditions. © 1994 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, is in the public dotmain in the United states of America

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Acute airway obstruction following placement of a subclavian Hickman catheter

The purpose of this case report is to describe the events, intervention, and aetiology which led to acute airway obstruction in an adult patient after the placement of a Hickman catheter. Airway obstruction secondary to superior vena cava obstruction occurred after placement of a subclavian vein Hickman catheter. This was felt to occur, in part, to a narrowed superior vena cava as evident by subclavian venography. It resulted in emergency oral tracheal intubation to relieve airway obstruction. Shortly after removal of the Hickman catheter, the signs of superior vena cava obstruction syndrome resolved and the patient was extubated without incidence. It is concluded that, although rare, the serious complication of acute airway obstruction can occur after placement of a Hickman catheter.     

Nitric oxide synthase activity is inducible in rat,but not rabbit alveolar macrophages,with a concomitant reduction in arginase activity

Alveolar macrophages were obtained by broncho-alveolar lavage of isolated rat and rabbit lungs and cultured (2.5 × 10⁶ cells/dish) for 18 h in the absence or presence of bacterial lipopolysaccharides (LPS) alone or in combination with cytokines. Thereafter, accumulation of ³H-citrulline (NO synthase activity) and ³H-ornithine (arginase activity) were determined.During incubation of rat alveolar macrophages with ³H-arginine clear amounts of ³H-citrulline and ³H-ornithine (3.8 and 4.6% of the added ³H-arginine, respectively) were formed and most of these metabolites appeared in the incubation medium (ratios extra-/intracellular of 17 and 70 for ³H-citrulline and ³H-ornithine, respectively). When rat alveolar macrophages had been cultured with LPS the formation of ³H-citrulline was increased about 30-fold and this was accompanied by a reduction in ³H-ornithine formation of about 60%. The effects of LPS were largely attenuated by dexamethasone (10 mol/1). Inhibition of NO synthase by N^G-monomethyl-l,-arginine (l-NMMA, 100 mol/1) in LPS treated alveolar macrophages reduced the formation ³H-citrulline by more than 90% and restored the ³H-ornithine formation. After culturing in the presence of LPS the ratios extra/intracellular of ³H-citrulline and ³H-ornithine were markedly enhanced and this effect was not dexamethasone sensitive. During incubation of rabbit alveolar macrophages a marked formation of ³H-ornithine (about 5.3% of the added ³H-arginine), but no significant formation of ³H-citrulline could be detected. Pretreatment with LPS tended to enhance the formation of ³H-ornithine (by 50%) without effects on ³H-citrulline. Rabbit-interferon and/or tumor necrosis factor- present together with LPS during the culture period did not result in a significant ³H-citrulline formation. Under all conditions tested, culture media of rabbit alveolar macrophages did not contain significant amounts of nitrite (less than 0.5 nmol) whereas in culture media of untreated rat alveolar macrophages 22 nmol nitrite (per 18 h) were detected, and LPS induced a 3-fold nitrite accumulation, an effect prevented by dexamethasone.In conclusion, in rabbit alveolar macrophages NO synthase activity was not detectable and could also not be induced by LPS and different cytokines, whereas in rat alveolar macrophages NO synthase was readily inducible. Alveolar macrophages of both species showed marked arginase activity. After induction of marked NO synthase activity, ornithine formation was largely reduced possibly by concomitant inhibition of arginase and/or withdrawn of arginine from arginase.     

Intracapsular Hip Fracture: Increased Cortical Remodeling in the Thinned and Porous Anterior Region of the Femoral Neck

It has been shown previously that the antero-inferior cortex is subjected to maximal tensile stress during a fall onto the greater trochanter. We have recently shown that in cases of femoral neck fracture, cortical thinning and porosity is greatest in the anterior and antero-inferior region of the femoral neck. To investigate whether this is due to increased remodeling, we have quantified surface-based parameters associated with Haversian remodeling in femoral neck biopsies from women with intracapsular hip fracture and post-mortem controls. Cryostat sections of chilled biopsies were reacted for either tartrate-resistant acid phosphatase (TRAP) or alkaline phosphatase (ALP) activity. Proportions of active canals were determined in each quadrant (inferior, anterior, superior, posterior) of the femoral neck. The biopsies were then embedded in methacrylate to permit histomorphometry using Goldner’s and Solochrome sections. In the cases there was no significant increase in the proportion of canals undergoing remodeling in the cortex as a whole (p = 0.846), but the regional distribution of remodeling was markedly different from that in the controls. In the anterior cortex, the proportion of canals undergoing remodeling was increased by 56% (p = 0.0087); in contrast there was a relative decrease of 35% in the superior region (p = 0.0047). In the anterior cortex of cases there were 76% and 42% increases in the proportions of eroded (p = 0.019) and osteoid-bearing (p = 0.041) canals, respectively. In the superior region, the decrease in the proportion of remodeling sites was due to a marked decrease in canals with an osteoid surface (51%; p = 0.0031). Covariance analysis with cortical porosity as the dependent variable showed that porosity was significantly dependent on the regional distribution of eroded (p = 0.033) but not on the distribution of forming (p = 0.153) canals (R ²adj = 0.51). Cellular levels of TRAP and ALP were significantly elevated in the anterior region of cases compared with the controls (TRAP 55%, p = 0.006; ALP 36%, p = 0.003). For the posterior and inferior regions there were no marked differences in cellular TRAP and ALP levels compared with control values. These data show that the increased cortical thinning and increased porosity we have previously observed in the anterior cortex in cases of hip fracture are associated with increased indices of Haversian remodeling. These findings are consistent with the hypothesis that, in cases of hip fracture, remodeling imbalance in the anterior cortex is a continuing process up to the time of fracture and is due to increased osteoclastic cellular activity associated with an osteoblastic response that is inadequate to prevent bone loss. Received: 16 November 1998 / Accepted: 17 February 1999     

Effects of selective phosphodiesterase inhibitors on platelet-activating factor- and antigen-induced airway hyperreactivity, eosinophil accumulation, and microvascular leakage in guinea pigs

There is currently interest in the potential use of selective inhibitors of cyclic nucleotide phosphodiesterases (PDE) in the treatment of asthma. In this study we examined the effects of three selective PDE inhibitors, milrinone (PDE III), rolipram (PDE IV) and zaprinast (PDE V), on the broncoconstriction produced by antigen and histamine, the airway hyperreactivity and microvascular leakage after aerosol exposure to platelet-activating factor (PAF) and antigen, and the antigen-induced eosinophil infiltration in guinea-pig lung. Inhaled rolipram (0.01–10 mg ml^–1) inhibited dose dependently the bronchospasm produced by aerosol antigen (5 mg ml^–1) an anaesthetised, ventilated guinea-pigs. Rolipram (10 mg ml^–1) produced maximal inhibition of antigen-induced bronchoconstriction but only partial inhibition of the response to aerosol histamine (1 mg ml^–1). Milrinone and zaprinast (each 10 mg ml^–1) showed weak, or no, inhibitory effects against bronchoconstriction produced by aerosol antigen or histamine. Pretreatment with rolipram (10 mg kg^–1, i.p.) prevented airway hyperreactivity to histamine which develops 24 h after exposure of conscious guinea-pigs to aerosol PAF (500 g ml^–1) or antigen (5 mg ml^–1). The pulmonary eosinophil infiltration obtained with 24 h of antigen-exposure was inhibited by rolipram. In contrast, milrinone and zaprinast (each 10 mg kg^–1, i.p.) failed to reduce either the airway hyperreactivity of the eosinophil accumulation in these animals. Rolipram (1–10 mg ml^–1) reduced the extravasation of Evans blue after aerosol PAF (500 g ml^–1) at all airway levels while a lower dose (0.1 mg ml^–1) was only effective at intrapulmonary airways. Rolipram (0.01–1 mg ml^–1) markedly reduced airway extravasation produced by inhaled antigen (5 mg ml^–1). Zaprinast (1–10 mg ml^–1) was also effective against airway microvascular leakage produced by aerosol PAF or antigen while milrinone (10 mg ml^–1) had no antiexudative effect. These data support previous suggestions that pharmacological inhibition of PDE IV results in anti-spasmogenic and anti-inflammatory effects in the airways and may be useful in the treatment of asthma.     

Emergency ventilation using the Combitube in cases of difficult intubation

Summary The esophageal-tracheal Combitube (Sheridan, Argyle, NY) is a new device for emergency intubation, which can be inserted blindly without the use of a laryngoscope. Ventilation is independent of the position of the Combitube in either the esophagus or the trachea, since ventilation is always provided by the tube's double channel. The tracheal channel acts as a conventional endotracheal airway and has an open distal end. The esophageal channel has a blocked distal end, so that together with the inflated distal cuff it acts as an esophageal obturator in cases of esophageal intubation. Perforations at the pharyngeal section direct the airflow to the trachea. At the oropharyngeal section a large elastic balloon is positioned in order to obturate the oral cavity and the nasopharynx. Two patients are described to exemplify the Combitube's clinical use. Both had rapidly enlarging cervical hematomas causing upper airway obstruction and thus requiring immediate intubation. Endotracheal intubation failed because the glottis could not be visualized with a laryngoscope. In both cases the Combitube was applied successfully and adequate ventilation was provided via the Combitube placed esophageally. To better secure each patient's airway, tracheotomy was performed during ventilation without any complications.