甲乙型肝炎血清MAO同工酶活性变化研究

用荧光分光光度法检测了血清单胺氧化酶（ＭＡＯ）同工酶Ａ（ＭＡＯ－Ａ）和同工酶Ｂ（ＭＡＯ－Ｂ）活性，结果表明血清ＭＡＯ－Ｂ活性急性期甲肝组较正常对照组显著升高，慢性期乙肝极显著升高；二型肝炎组的ＭＡＯ－Ａ活性升高程度无统计学意义。二型肝炎ＭＡＯ同工酶活性改变与其它肝功生化指标无明显相关性，表现血清ＭＡＯ同工酶活性与肝功损害程度不相关。     

Perturbation of copper (Cu) homeostasis and expression of Cu-binding proteins in cadmium-resistant lung fibroblasts.

To probe mechanisms of cadmium (Cd) damage to the lung extracellular matrix (ECM), we developed Cd-resistant (CdR) rat lung fibroblasts (RFL6) by incubation with graded concentrations of Cd. CdR cells downregulated lysyl oxidase (LO), a copper (Cu)-dependent enzyme essential for crosslinking of collagen and elastin in the ECM, in conjunction with upregulation of other Cu-binding proteins including Cu,Zn-superoxide dismutase (SOD1), copper chaperone for SOD1 (CCS1), metallothionein (MT), and Menkes P-type ATPase (ATP7A), a Cu transporter in the membrane of the Golgi apparatus, as well as gamma-glutamylcysteine synthetase (gamma-GCS), an enzyme for glutathione biosynthesis. Reduction and loss of cytoplasmic distribution of LO in CdR cells were accompanied by its dislocation with the Menkes P-type ATPase and the endoplasmic reticulum marker. CdR cells displayed a defect in LO catalytic activity but an enhancement in Cu,Zn-SOD catalytic activity consistent with the protein expression levels of these enzymes. Although long-term Cd exposure of cells enhanced the Menkes P-type ATPase protein expression, actually, it reduced Cu-dependent catalytic activity of this enzyme in parallel with the deficiency of LO. The low level of 64Cu bound to the LO fraction and the high level of 64Cu bound to the MT fraction provide direct evidence for limitation of Cu bioavailability for LO existing in the CdR cells. These results suggest that downregulation of LO is linked with upregulation of other Cu-binding proteins and with alteration in Cu homeostasis in the CdR phenotype.     

ACUTE EFFECT OF ETHANOL ON RENAL ELECTROLYTE TRANSPORT IN THE RAT

1. Despite human and animal studies, the direct effect of ethanol on renal water and electrolyte transport is poorly understood. The acute effect of increasing plasma concentrations of ethanol was evaluated in a water diuretic anaesthetized rat model which inhibits endogenous arginine vaso-pressin (AVP) release. 2. Ethanol at a plasma concentration of 1.69 ±0.28 mmol/L produced an immediate increase in urine flow (174 ± 11 μL/min pre-ethanol and 189 ± 13 and then 206 ± 12 μL/min during the ethanol infusion; P<0.001) as well as an increase in fractional sodium excretion (0.17 ± 0.04 to 0.28 ± 0.05 and 0.27 ± 0.05%; P<0.001). There was also a brief phosphaturia. These increases in electrolyte excretion had returned to control values by 20 min despite a further increase in the plasma ethanol concentration. 3. The urinary excretion of potassium, calcium and magnesium was not altered nor was glomerular filtration rate or renal plasma flow. 4. Ethanol at a mean concentration of 1.60 mmol/L did not alter the action of a maximal concentration of AVP (75 ng/kg) on water or electrolyte transport. However, the antidiuretic effect of a submaximal concentration of AVP (7.5 ng/kg) was augmented by ethanol at concentrations of 1.63 and 0.98 mmol/L. 5. These studies suggest that the ethanol induced diuresis commonly ascribed to inhibition of AVP secretion may also be due to other intrarenal effects of ethanol, possibly acting within the proximal tubule. These results also confirm recent in vitro findings that while ethanol does not inhibit the action of a maximal concentration of AVP, it does modulate the effects of lower AVP concentrations.     

新型骨水泥粘接固定骨折的动物实验研究

目的：应用磷酸镁骨水泥(magnesium phosphate cement，MPC)粘接固定家兔胫骨平台骨折，探讨其治疗效果、粘接和降解机理。方法：20只家兔分为两组，第1组15只，第2组5只，通过开放截骨法建立家兔双侧胫骨平台骨折模型。第1组：实验组用MPC骨水泥固定，对照组用“L”形钢板固定。第2组：实验组也同样用MPC骨水泥固定，而对照组作空白对照。通过大体观察、影像学、组织学及电解质检查，探讨MPC骨水泥治疗骨折的效果、对体内电解质的影响、粘接和降解机理。结果：6周后实验组都获得稳定的骨折愈合，没有发现骨折错位及延迟愈合，MPC骨水泥逐渐被吸收，对体内电解质无明显影响，其对骨折的治疗和钢板固定组达到同样的治疗效果。而空白对照侧均出现骨折错位、畸形愈合。通过对标本的组织学检查发现其粘接机理为镶嵌固定，并通过溶解而逐步降解。结论：MPC骨水泥具有一定的粘接强度，能降解，对体内电解质干扰小，是一种较为理想的骨水泥，可以用于骨折的粘接固定。     

Distal radial fractures Injectable calcium phosphate bone cement versus conventional treatment

AMEDLINEsearchwasconductedtoidentifystudiespublishedfromJanuary1999toMarch2004thatcom-paredinjectablecalciumphosphatebone(NorianSRS)cementwithconventionaltreatmentindistalradialfrac-tures.Fromalistof13articlesidentifiedfromthesearchstrategy,fourarticleswe…     

Accelerating cardiac cine 3D imaging using k-t BLAST.

By exploiting spatiotemporal correlations in cardiac acquisitions using k-t BLAST, gated cine 3D acquisitions of the heart were accelerated by a net factor of 4.3, making single breathhold acquisitions possible. Sparse sampling of k-t space along a sheared grid pattern was implemented into a cine 3D SSFP sequence. The acquisition of low-resolution training data, which was required to resolve aliasing in the k-t BLAST method, was either interleaved into the sampling process or obtained in a separate prescan to allow for shorter breathhold durations in patients with heart disease. Volumetric datasets covering the heart with 20 slices at a spatial resolution of 2 x 2 x 5 mm3 were recorded with 20 cardiac phases in a total breathhold duration of 25-27 sec, or 18 sec if partial Fourier sampling was additionally employed. The feasibility of the method was demonstrated on healthy volunteers and on patients. The comparison of endocardial area derived from single slices of the 3D dataset with values extracted from separate single-slice acquisitions showed no significant differences. By shortening the acquisition substantially, k-t BLAST may greatly facilitate volumetric imaging of the heart for evaluation of regional wall motion and the assessment of ventricular volume and ejection fraction.     

Inhibition of the amorphous calcium phosphate phase transformation reaction by polyphosphates and metal ions

Summary The induction time for amorphous calcium phosphate (ACP) phase transformation was monitored at pH 7.4 and T=25°C with [Ca²⁺]₀=[PO₄]₀=4.0×10⁻³ M, as a function of added crystal growth inhibitors Mg²⁺, Sr²⁺, Zn²⁺, pyrophosphate (PP), and tripolyphosphate (TPP). Metal ions increase the induction time for the initiation of the phase change reaction in the order Zn²⁺<Sr²⁺<Mg²⁺. For polyphosphates it was observed that both PP and TPP are potent inhibitors with TPP more effective than PP as expected. The combination of Mg²⁺ or Sr²⁺ and PP or TPP leads to a synergistic delay in the onset of the phase conversion. The greatest inhibition was observed for Mg²⁺ and TPP. Reaction solutions containing 2.0×10⁻⁴ M Mg²⁺ and 4.0×10⁻⁵ M TPP resulted in a 90% increase in the induction time over what would be anticipated from an additive effect from these species.     

Characteristics of antibody responses induced in mice by protein allergens

Whereas many foreign proteins are immunogenic, only a proportion is also allergenic, having the capacity to induce the quality of immune response necessary to support the production of IgE antibody. We have demonstrated previously that intraperitoneal administration to mice of proteins such as ovalbumin (OVA) or the industrial enzyme A. oryzae lipase, which possess significant allergenic potential, stimulates the production of both IgG and IgE antibody. Identical exposure to bovine serum albumin (BSA), a protein with limited potential to cause immediate respiratory or gastrointestinal hypersensitivity reactions, induced IgG responses only. In the current investigations, the quality of immune responses induced following exposure to these proteins via mucosal tissue (intranasal) has been compared with those provoked following administration via a non-mucosal (intraperitoneal) route of exposure. Intranasal or intraperitoneal administration of BSA, OVA or A. oryzae lipase elicited in each case vigorous IgG and IgG1 antibody responses. For all three proteins, at every concentration tested, and via both routes of exposure, IgG1 antibody titres paralleled closely IgG titres. However, the three materials displayed a differential potential to provoke IgE responses and this correlated with their known allergenic potential in humans. Thus, OVA and A. oryzae lipase stimulated strong IgE antibody responses, whereas BSA provoked low titre IgE only at the highest concentration tested (5% administered intraperitoneally). The quality of induced responses was not affected by the route of exposure. It would appear, therefore, that the stimulation of IgG and IgG1 antibody responses is a reflection of protein immunogenicity whereas protein allergenicity is associated with the induction of strong IgE responses.     

Evaluation of filling materials in membrane‐protected bone defects. A comparative histomorphometric study in the mandible of miniature pigs.

In recent years, bone grafts and bone substitutes have been increasingly utilized underneath barrier membranes to optimize the treatment outcome of bone reconstructive therapy for defects in the alveolar process. In the present study, 4 different filling materials were evaluated in bone defects of similar dimensions in the mandible of miniature pigs. Blood clots and autografts were used as controls. The defects were covered with barrier membranes and allowed to heal for 4, 12 or 24 weeks. Histologic examination demonstrated that bone repair progressed through a programmed sequence of maturation steps closely resembling the pattern of bone development and growth regardless of whether bone grafts or substitutes were present or not. Histomorphometric analysis showed that autologous bone grafts (autografts) had the best osteoconductive properties during the initial healing period, with 39% of newly formed bone inside the membrane-covered defects at 4 weeks of healing. In addition, 87% of the graft surfaces were already covered by bone at this time. Both values were significantly higher for autografts than for the 4 alternative bone fillers (P < or = 0.05). At 12 weeks, these differences were no longer apparent, with all 5 filling materials showing similar values. Among the tested bone substitutes, tricalcium phosphate (TCP) showed a significantly higher percentage of bone fill at 24 weeks of healing. It can be concluded that sites filled with autografts clearly demonstrated the best results underneath barrier membranes in the early phase of healing. As far as degradation and substitution are concerned, TCP showed the most promising results. This filler, however, needs to be tested further in a more demanding animal model. Less favorable results were obtained for coral-derived hydroxyapatite granules and for demineralized freeze-dried bone allografts.     

肉毒碱对实验性心肌损伤线粒体呼吸酶的影响

以大剂量维生素Ｄ造成心肌损伤模型，以肉毒碱作为影响因素，通过电镜细胞化学方法，观察了肉毒碱对心肌线粒体细胞色素Ｃ氧化酶和琥珀酸脱氢酶的作用。结果表明，肉毒碱具有提高线粒体呼吸酶活性及保护线粒体膜结构的应用，从而保护了呼吸链的完整性，改善了心肌氧化磷酸化功能。