Value of radiopaque markers in identifying partial small bowel obstruction

Confirming partial small bowel obstruction is often a diagnostic challenge. In this case report, 4-mm solid radiopaque markers were used in 4 patients to show partial small bowel obstruction. Results of enteroclysis were normal in 2 of the 4 patients, and the markers were used to challenge suspected partial obstruction. The markers coalesced in the region of the partial obstruction, which was confirmed at surgery. Enteroclysis is the examination of choice in the diagnosis of partial small bowel obstruction. However, examinations with false- negative results can occur, particularly with adhesive and/or intermittent obstructions. The use of radiopaque markers in these cases proved an effective and useful method of establishing the diagnosis of partial small bowel obstruction, particularly in the 2 cases in which enteroclysis results were normal. Prospective studies are needed to establish the feasibility of this novel technique. (Gastroenterology 1996 Jun;110(6):1958-63)     

alpha-Actinin and vinculin in normal and thrombasthenic platelets

Recently, the contractile protein alpha-actinin was identified in normal human platelets by its antigenic cross-reaction with a monospecific antibody to purified muscle alpha-actinin. In this study, we extend that preliminary identification of platelet alpha-actinin. Amino acid analysis, one-dimensional peptide maps, and silver stain analysis on polyacrylamide gels demonstrate that human platelet alpha- actinin shows a greater degree of similarity to smooth muscle alpha- actinin than to striated muscle alpha-actinin. There is no evidence to suggest that alpha-actinin is a glycoprotein. In addition, we find that thrombasthenic platelets, which are deficient in glycoproteins IIb and IIIa (GPIIb and GPIIIa) contain normal amounts of alpha-actinin, confirming the recent finding that alpha-actinin and GPIIIa are different proteins in human platelets. We demonstrate that both normal and thrombasthenic platelets also contain vinculin, a 130,000-dalton polypeptide found in many cell types at sites of end-on attachment of microfilaments to the plasma membrane. Thus, the thrombasthenic defect in GPIIb and GPIIIa does not diminish the content of either alpha- actinin or vinculin.     

Functional evaluation of cerebral cortex in dementia with Lewy bodies

Neurochemical investigations have demonstrated central cholinergic dysfunction in patients with dementia with Lewy bodies (DLB). Central cholinergic circuits of the human brain can be tested non-invasively by coupling peripheral nerve stimulation with transcranial magnetic stimulation of the contralateral motor cortex. This test, named short latency afferent inhibition has been shown in healthy subjects to be sensitive to the blockage of muscarinic acetylcholine receptors and it is impaired in patients with Alzheimer disease (AD), a cholinergic form of dementia, while it is normal in non-cholinergic forms of dementia such as fronto-temporal dementia. We evaluated short latency afferent inhibition in a group of patients with DLB and compared the data with that from a group of AD patients and a control group of age-matched healthy individuals. Short latency afferent inhibition was significantly reduced in DLB and AD patients. The findings suggest that this method can be used as a non-invasive test for the assessment of cholinergic pathways in patients with dementia and may represent a useful additional tool for discriminating between cholinergic and non-cholinergic forms of dementia.     

Screening potential blood donors at risk for human immunodeficiency virus

Even though all blood donated for transfusion is tested for the presence of human immunodeficiency virus (HIV) antibodies, there exists a period of time after infection by the virus before these antibodies can be detected. Blood donated during this window period is capable of transmitting the virus. Therefore, the blood of persons who are at risk for acquired immune deficiency syndrome (AIDS) should not enter the blood supply. Over a period of 4 months, 6573 potential blood donors who entered fixed and mobile blood collection sites in two cities were exposed to alternative interventions the aim of which was to exclude persons at risk for AIDS. We compared the interventions to one another and to existing materials in terms of the numbers of at-risk persons who did or did not donate for transfusion, the amount of attention paid to the materials, the scores on a comprehension test, and the self-reports by the subjects of attitudes towards the various interventions. At-risk donors who were asked direct AIDS risk behavior questions in addition to the current health history questions were more likely to be screened out than those who underwent alternative health history interviews (p less than 0.01). Potential donors paid more attention to the experimental brochures than to the experimental video or current materials (p less than 0.05). Comprehension scores were better for the new brochure and the video than for the current brochure (p less than 0.05). Donors were not offended by the experimental interventions.(ABSTRACT TRUNCATED AT 250 WORDS)     

Probable reasons that autologous blood was not donated by patients having surgery for which crossmatched blood was ordered

Preoperative autologous blood donation is used by only a small percentage of surgery patients for whom crossmatched blood is ordered. To document the reasons the patients failed to donate, the medical records of surgical patients at three university and three community hospitals were studied. All procedures for which crossmatched blood was ordered, but for which autologous blood was not available, were included (n = 8121). Probable reasons for nondonation were found in 72 percent of university hospital patients and 65 percent of community hospital patients (n = 6064 and n = 2057, respectively). The most frequent reasons for nondonation among university hospital patients were emergency surgery (27%) and age less than 12 years (17%), and those among community hospital patients were emergency surgery (42%) and American Society of Anesthesiologists physical status greater than or equal to 4 (20%). Surprisingly, anemia (hemoglobin less than 11 g/dL [less than 110 g/L]) as the only limitation to donation was rarely found: this was the sole reason in only 3.3 percent of university hospital and 4.5 percent of community hospital patients. Overall, of 8121 patients who failed to donate autologous blood, 5731 (71%) had legitimate medical reasons. The remaining 2390 (29%) had no identifiable reason for nondonation, and recruitment efforts should be focused on them and their surgeons.     

Molecular characterization of quinine/quinidine drug-dependent antibody platelet interaction using monoclonal antibodies

Two murine monoclonal antibodies, FMC 25 and AN 51, directed against distinct epitopes on the glycoprotein Ib complex, have been used to further define the mechanism of quinine/quinidine drug-dependent antibody interaction with platelets. FMC 25, directed against an epitope on glycoprotein IX, had no effect on platelet aggregation induced by collagen or adenosine diphosphate and little, if any, effect on ristocetin-induced platelet agglutination. FMC 25 and its (Fab)2 fragment, however, were potent inhibitors of drug-dependent antibody- induced platelet aggregation and blocked binding of drug-dependent antibody to platelets as assessed by indirect platelet immunofluorescence. In contrast, AN 51, directed against an epitope on the alpha-subunit of glycoprotein Ib, blocked ristocetin-induced, factor VIII/von Willebrand factor (FVIII/vWF)-dependent platelet agglutination but not drug-dependent antibody-induced platelet aggregation or binding of drug-dependent antibody to platelets. Selective proteolytic removal of the majority of the alpha-subunit of glycoprotein Ib (glycocalicin) from platelets by treatment with calcium- dependent protease did not affect binding of drug-dependent antibody. In addition, a quinidine-dependent antiplatelet antibody immunoprecipitated glycoprotein Ib complex from normal platelets and the membrane-associated proteolytic remnant of the glycoprotein Ib complex from calcium-dependent protease-treated platelets. Preincubation of drug-dependent antibody with purified glycoprotein Ib complex inhibited subsequent binding of antibody to platelets, but the separated components, glycoprotein Ib and glycoprotein IX, were both ineffective, suggesting that the normal interaction between glycoprotein Ib and glycoprotein IX in the intact complex was necessary for drug-dependent antibody recognition. The functional response of platelets to drug-dependent antibody was not mediated by way of platelet Fc receptor, since aggregation of washed platelets by acetone- aggregated IgG was not inhibited by FMC 25 (Fab)2. FVIII/vWF was not required for drug-dependent antibody-induced platelet aggregation. The combined evidence is consistent with quinine/quinidine-dependent antibody-platelet interaction occurring by way of a FVIII/vWF- independent, Fc receptor-independent mechanism that probably involves binding of antibody to glycoprotein IX or the beta-subunit of glycoprotein Ib or both.     

等电聚焦法检测碱性磷酸酶同工酶在肝癌和肝癌骨转移鉴别诊断中的应用

目的探讨碱性磷酸酶(ALP)同工酶在肝癌和肝癌骨转移鉴别诊断中的应用。方法用等电聚焦法(IEF)分离测定80例健康体检者和153例肝脏疾病患者血清中的ALP同工酶。结果采用神经氨酸苷酶处理标本后,IEF能分辨出ALP同工酶pI6.0、pI6.1、pI6.4和pI6.5共4个亚型。ALP的pI6.0和pI6.4亚型的检出率在健康体检组、非肝癌组、肝癌组之间差异无统计学意义(P0.05);pI6.5亚型的检出率在肝癌患者组明显高于健康体检组和非肝癌组(P0.01);pI6.1检出率在肝癌骨转移组明显高于肝癌无骨转移组、健康体检组和非肝癌组(P0.01)。pI6.5用于肝癌诊断的灵敏度是60.7%,特异性是83.3%,阳性预测值是69.2%,阴性预测值是77.4%,符合率为74.7%。pI6.1用于肝癌骨转移的诊断灵敏度是70.0%,特异性是81.3%,阳性预测值是84.5%,阴性预测值是84.8%,符合率为77.6%。结论 IEF法能分离ALP同工酶不同亚型,pI6.5亚型可作为肝癌鉴别诊断指标,pI6.1亚型可作为肝癌骨转移鉴别诊断指标。     

Double-stranded RNA induces sickle erythrocyte adherence to endothelium: a potential role for viral infection in vaso-occlusive pain episodes in sickle cell anemia

Vaso-occlusive pain episodes in sickle cell anemia are hypothesized to be precipitated by adherence of sickle erythrocytes to vascular endothelium in the microcirculation. Febrile episodes, thought to be viral in etiology, are frequently associated with vaso-occlusion; however, a direct link between viral infection and vascular occlusion has not yet been established. Many pathogenic viruses contain double- stranded RNA or replicate through double-stranded RNA intermediates. Double-stranded RNA has been shown to induce vascular cell adhesion molecule-1 (VCAM-1) protein expression on endothelial cells. Recently, a new adhesion pathway has been described between VCAM-1 expressed on cytokine stimulated endothelium and the alpha 4 beta 1 integrin complex expressed on sickle reticulocytes. Based on these observations, the hypothesis was developed that viral infection, through double-stranded RNA intermediates, increases endothelial VCAM-1 expression leading to sickle erythrocyte adhesion to endothelium via an alpha 4 beta 1-VCAM-1- -dependent mechanism. In support of this hypothesis, endothelial cells exposed to the synthetic double-stranded RNA poly(I:C) or the RNA virus parainfluenza 1 (Sendai virus) express increased levels of VCAM-1 and support increased sickle erythrocyte adherence under continuous flow at 1.0 dyne/cm2 shear stress as compared with unstimulated endothelium. Blocking antibodies directed against either VCAM-1 on the endothelium or alpha 4 beta 1 on sickle erythrocytes inhibit nearly all of the increased sickle cell adherence caused by poly(I:C) or Sendai virus. These results support the hypothesis that viruses, through double- stranded RNA elements, can induce sickle erythrocyte adherence to endothelium through alpha 4 beta 1-VCAM-1--mediated adhesion and provide a potential link between viral infection and microvascular occlusion precipitating sickle cell pain episodes.