Remote medulla ablongata ventral acute subarachnoid hemorrhage following cervical spinal surgery: A case report

IntroductionThe incidence of remote intracranial hemorrhage (RICH) in patients during spinal surgery is rare and the detailed mechanism remains unclear.Presentation of caseA 55-year-old man had undergone cervical discectomy and fusion at C5–6 and C6–7 due to herniated disc and secondary spinal canal stenosis. He had severe headache 20 h postoperatively and his drain output increased from 100 to 350 mL in the second 10 h after surgery. Computed tomography (CT) and magnetic resonance imaging (MRI) were performed and he was diagnosed with acute subarachnoid hemorrhage in the ventral medulla oblongata. The drainage tube was quickly removed. Infusion of hypertonic saline was used to reduce intracranial pressure and nimodipine prevented vasospasm around the brainstem. The patient made a gradual, satisfactory recovery with conservative treatment.DiscussionThe most likely pathomechanism leading to RICH is venous bleeding due to rapid leak of a large amount of cerebral spinal fluid (CSF) after spinal surgery. If the patient has a headache or neurological complaints after spinal surgery, immediate imaging is recommended to confirm the diagnosis. Treatment depends on the amount and location of intracranial hemorrhage.ConclusionRICH is a serious but rare complication of spinal surgery and cerebellar hemorrhage is the most common. The most important pathomechanism leading to RICH after spinal surgery is venous bleeding due to rapid leak of a large amount of CSF. Timely CT is necessary to exclude RICH. Treatment of RICH depends on the size of the intracranial hematoma and the patient’s symptoms.     

Interaction of immunoglobulin with actin

Actin can form specific, direct associations with immunoglobulin resulting in soluble complexes or cross-linked matrices. This interaction can be detected by four in vitro assays using purified components: (1) actin enhances the cytophilic activity of guinea pig IgG2; (2) in solutions of low ionic strength, actin and IgG2 co-precipitate: (3) soluble complexes exist in 0.1 M KCl as revealed by the displacement of actin from its expected sedimentation pattern in a gradient of sucrose when in the presence of IgG 1, IgG2, or IgM; (4) immunoglobulin (IgG1, IgG2, BGG)‡: increases the viscosity of F-actin solutions, presumably by crosslinking F-actin filaments. These data suggest that direct interaction of a cytoskeletal protein with a cell surface receptor is possible.     

Pharmacokinetics,cerebrospinal fluid penetration,and metabolism of piroxantrone in the Rhesus monkey

Summary Piroxantrone is an anthrapyrazole derivative with broad anti-tumor activityin vitro and less cardiac toxicity than the anthracyclines. The metabolic pathways and central nervous system penetration of piroxantrone have not been determined. In this study we examined the pharmacokinetic behavior of piroxantrone in plasma and cerebrospinal fluid in a non-human primate model. In addition, a urinary metabolite of piroxantrone was isolated and its cytotoxicity evaluatedin vitro. The disappearance of piroxantrone from plasma after an intravenous dose of 150 mg/m² given over 60 minutes was biexponential with mean t_1/2 alpha of 1.0 minutes and a mean t_1/2 beta of 180 minutes. The mean area under the curve was 220 M·min and the clearance was 1420 ml/min/m². Piroxantrone was not detectable in the cerebrospinal fluid.Piroxantrone and three other compounds not present in pre-treatment samples were detected in urine. The major urinary metabolite was isolated. Its cytotoxicity against MOLT-4 cellsin vitro was at least one log less than that of piroxantrone. In addition, one of the other compounds detected in urine was determined to be a glucuronide conjugation product of the major metabolite.The results of this study may be useful in the interpretation of the activity and toxicity of piroxantrone in clinical trials.     

胆必清对内毒素诱导的大鼠腹腔巨噬细胞内游离钙浓度的影响

目的：探讨中药胆必清对内毒素诱导的大鼠腹腔巨噬细胞游离钙浓度的影响。方法：制备大鼠腹腔巨噬细胞并在体外进行孵育,使用荧光探针用荧光法测定钙浓度。巨噬细胞随机分为正常对照组,内毒素LPS组,小、中和大剂量中药组。结果：LPS能诱导巨噬细胞[Ca2^ ]i的升高。加入胆必清后,[Ca2^ ]i可有不同程度的降低。结论：胆必清能抑制LPS诱导的大鼠腹腔巨噬细胞内的[Ca2^ ]i升高,提示该药具有抗炎和免疫调节作用。     

人工心脏圆盘泵的流动特性研究

人工心脏（血泵）一直存在泵体对血细胞剪切力过大和流速过快容易引起溶血的问题。为了研究人体正常血压情况下,血泵内部剪切力和速度场的分布情况,选择圆盘泵叶轮代替传统离心泵叶轮,对两种模型进行数值计算,分析不同叶轮内部剪切力和速度场的分布规律。研究表明传统离心泵内部流速高,叶片表面剪切力大,对血细胞的伤害大。圆盘泵相比传统离心泵,剪切力更小,流场速度分布均匀,流速更小。和传统离心泵相比,不同转速下圆盘泵能降低溶血的发生率。圆盘泵叶片数为6片时,抗溶血性能更好。研究结果为血泵的优化提供理论依据。     

Prenatal diagnosis of galactosemia

The experience from three different European centres with the prenatal diagnosis of galactose-1-phosphate-uridyltransferase (GALT) deficiency is presented and the question whether or not there is a need for prenatal diagnosis of this disorder is discussed. Most prenatal diagnoses (n=50) have been performed by assay of GALT activity in cultured amniotic fluid cells. The assay used is reliable and clearly distinguishes homozygous affected fetuses (n=11; 0%–2.3% of mean control enzyme activity) from non-(homozygous)-affected fetuses. The GALT assay for cultured amniocytes was adapted to assay the enzyme directly in chorionic villi. The experience with chorionic villi comprises 23 cases with 5 affected fetuses (0%–4.2% of mean control enzyme activity). In 36 cases galactitol was determined in amniotic fluid supernatant by gas chromatography-mass spectrometry. This method also differentiated affected (n=11; galactitol 5.9–10.6 mol/l) and unaffected pregnancies (galactitol 0.23–1.6 mol/l) clearly and has the advantage of providing a result within a day or two after amniocentesis. Prenatal diagnosis of galactosemia is undertaken rarely and sometimes for the wrong reasons, but it should perhaps be considered more seriously until better methods of treatment are established.     

Higher Kt/V is needed for adequate dialysis if the treatment time is reduced

The widely used Kt/V concept for quantitating haemodialysis(HD) and ensuring adequate dialysis is based on several assumptions.In order to simplify the urea kinetic modelling, the body isassumed to be a single well-mixed compartment. Previously, morephysiological two-compartment or blood flow distribution modelshave been used to explain the phenomenon of blood urea reboundafter dialysis. This study attempts to evaluate the effectsof a multi compartment model on the removal of urea, i.e. onthe adequacy of dialysis. Four different tissue compartmentsof similar size are used, with flow rates between 40 and 3600ml/min for a bodyweight around 70 kg, allowing for blood flowheterogeneity within and between skeletal muscles. Dialysisis simulated by removing blood containing urea and replacingit with blood free of urea, during isovolumetric conditionsand assuming no diffusion barriers for urea. Several importantconclusions can be drawn from the model. Firstly the removalof urea is dependent both on the time of dialysis and on thenumber of HD treatments per week despite constant Kt/V. Secondlythe blood urea concentration is increased after dialysis—‘urearebound’—in accordance with clinical data. Thirdlythe concept of blood flow distribution can fully explain thedifference between haemodialysis and peritoneal dialysis interms of Kt/V needed for adequate dialysis. Thus a weekly Kt/Vof 3.6 for HD 4 h 3 times per week removes the same amount ofurea as CAPD and a Kt/V of 2.1. Also, nightly intermittent PDrequires similar Kt/Vs (0.1 higher) as CAPD to obtain equivalentremoval of urea. Finally the crucial point is that the Kt/Vrequired for adequate dialysis must be increased if the dialysistreatment time is reduced. If not, the patient with renal insufficiencysuffers the risk of being under-dialysed.     

Imbalance between intraperitoneal coagulation and fibrinolysis during peritonitis of CAPD patients: the role of mesothelial cells

We compared peritoneal dialysis effluents from 18 CAPD patientswho had not suffered from peritonitis during the last 6 months(group 1) with the effluents from five patients with acute peritonitis(group 2), measuring activation markers of coagulation and fibrinolysis.These markers included prothrombin fragment F1+2 (F1+2), thrombin-antithrombinIII complex (TAT), fibrin monomer (FM), and fibrin degradationproducts (FbDP). In the dialysate of group 1 we found remarkablyhigh levels of F1+2, TAT and FM concomitant with a high concentrationof FbDP, indicating a high rate of intraperitoneal fibrin turnover.The balance between peritoneal generation and degradation offibrin was disturbed in untreated patients of group 2, who hadsignificantly higher levels of coagulation markers and a higherratio between FM and FbDP. Seven days after treatment with intraperitonealadministration of antibiotics and heparin, F1+2, TAT, FM andFbDP decreased significantly. To evaluate the role of mesothelial cells (MC) in the high peritonealfibrin turnover we investigated the expression of tissue-typeplasminogen activator (t-PA), urokinase-type plasminogen activator(u-PA), plasminogen activator inhibitor type-1 (PAI-1), andtissue factor in cultured human peritoneal MC under basal conditionsand after exposure to tumour necrosis factor (TNF) interleukin-1(IL-1), or bacterial lipopolysaccharide (LPS). The exposureof MC to TNF or to a lesser extent IL-1 or LPS reduced theirfibrinolytic activity by decreasing t-PA production and increasingPAI-1 synthesis. Furthermore the addition of TNF resulted inactivation of the coagulation cascade by the expression of tissuefactor. These in-vitro findings explain the imbalance betweenintraperitoneal coagulation and fibrinolysis during peritonitisof CAPD patients.