Omental transfer to the brain: an experimental study in hydrocephalic rabbits

Hydrocephalus is a common and potentially lethal condition in children that results from an imbalance between absorption and production of cerebral spinal fluid (CSF). Silastic shunts are inserted to drain excess CSF, but they are prone to a number of problems, and at times may be unreliable and ineffective. This study examines the physiological basis of a pedicled omental transfer to the brain as a functional conduit for CSF in an experimentally induced hydrocephalic rabbit model. The ability of the omentum to transport CSF from the subarachnoid space was tested using radioactive tracer substances: radio-iodinated serum albumin (125I-RISA), chromium 51-ethylenediaminetetraacetate (51Cr-EDTA), and technetium 99m (99mTc) glucoheptonate. Immediate ability of exteriorized omentum to transport artificial CSF, as well as transposed omental transport of subarachnoid CSF at 1 month, were examined. Nuclear scan measurements were correlated with clinical observation and a double-blind histological analysis with trichrome and hematoxylin-eosin stain. Exteriorized omentum rapidly absorbed 99mTc glucoheptonate-labeled artificial CSF, with a rapid appearance in the systemic circulatory and urinary systems. Transposed omentum to the brain in animals with artificially created hydrocephalus showed evidence of CSF-labeled 125I-RISA and 51Cr-EDTA absorption in those animals demonstrating histologically viable omentum.     

Monoclonal antibodies reactive with epitopes restricted to glial fibrillary acidic proteins of several species

The highly reproducible histochemical localization of glial fibrillary acidic protein (GFAP)? qualifies it as an important marker of astrocytes in both research and clinical applications. The primary objective of this study was to produce monoclonal antibodies having the advantage of invariant specificity, affinity, and titer to GFAP-specific epitopes of wide species distribution. We report here the characterization of four monoclonal antibodies that recognize the same or spatially close epitopes specific to GFAP. The epitope(s) detected has been phylogenetically conserved; human, bovine, ovine, canine, porcine, rabbit, guinea pig, rat, murine, and chicken brain homogenates all specifically absorb monoclonal antibody activity. Of importance to the routine application of these new anti-GFAP monoclonal antibodies is the demonstration here of the stability of the antigen-antibody interaction in normal, reactive, and neoplastic astrocytes of both rat and human origing following various methods of fixation.     

Nasal symmetry: a 10-year comparison between the Pigott and McComb nasal correction.

The objective assessment of the symmetry of the cleft lip nose has not been properly evaluated. A simple technique using enlarged photographs and area assessment is described. Two different techniques were assessed, the Pigott "alar leapfrog" technique and the McComb alar lift technique. The children were assessed at 10 years of age. The results show no differences in the linear measurements or when the symmetry is assessed in the frontal view. In the worm's eye view, the Pigott correction was shown to produce a more asymmetric nose when compared with the McComb technique. Both corrections produce significant asymmetry when compared with a control group.     

Management of recurrent ventricular tachyarrhythmias associated with Q-T prolongation

Eleven patients with acquired prolongation of the Q-Tc interval and recurrent ventricular tachyarrhythmias were studied. Five patients required 5 to 44 direct current shocks to correct prolonged ventricular tachyarrhythmias, and five were given at least two antiarrhythmic agents in an attempt to control the arrhythmias. In 4 of the 11 patients, when thioridazine, diuretic drugs and antiarrhythmic agents were withdrawn and hypokalemia or hypocalcemia corrected, ventricular tachyarrhythmias did not recur. The Q-Tc interval normalized in 2 to 3 days. Ventricular tachyarrhythmias were recurrent in the remaining seven patients, despite withdrawal of the drugs that caused the Q-Tc prolongation, attempted correction of hypokalemia when present and the administration of antiarrhythmic agents to four of the seven. All antiarrhythmic agents were then withdrawn in this group.

Immediately on the establishment of overdrive ventricular or atrioventricular sequential pacing in these patients, ventricular tachyarrhythmias were abolished. No breakthrough ventricular tachyarrhythmias occurred during temporary pacing. Temporary pacing was required for an average of 10 days and the Q-Tc interval normalized an average of 5 days from the onset of pacing. Three patients required a permanent pacemaker, one because of chronic complete heart block, one because of the sick sinus syndrome, and one because of frequent ventricular ectopic complexes complicating ischemic heart disease. All 11 patients survived their period of hospitalization.     

004 65岁以上收缩功能正常的心衰者的临床特点

众所周知,充血性心衰(CHF)为老年人较为常见的临床综合征之一.迄今关于左室收缩功能正常的CHF老人的相关临床特点远未清楚,本文特此进行了大样本分析. 对象与方法 4842例老年人,男1922例,女2920例,年龄66～103岁.尔后人均随访1年.旨在分析老年CHF年发病率,以及左室收缩功能正常的CHF老人相关临床特点. 结果随访期内,罹发1次或以上CHF者共425例次(8.8%/年).与未患发CHF老人相比,CHF老人平均年龄更大(79±6岁:77±5岁,P＜0.001),女性居多,尤以高龄女性更多,如85岁以上的高龄女性CHF年发病率约较65～69岁女性高2倍(14%∶6.6%,P＜0.001),AMI史、房颤、高血压、糖尿病、慢性阻塞型肺病、吸烟者均多,血脂及血肌酐亦高.多变量分析表明,罹患CHF与下列因素有关:老年尤其是高龄[年龄每增加5岁的患病奇数率(OR)女性1.2,男性1.1],AMI史(OR7.3),房颤者(OR3.0),糖尿病(OR2.1),肾功能不全(血肌酐≥1.5mg/dl的OR2.0),慢性阻塞肺病(仅老年女性的OR为1.8),以及左房、左室内径增大(内径每递增1cm的OR为2.0),和左室重量增加、左室收缩末期室壁张力增高、早期跨心房血流增多.超声心动图检测结果显示,CHF老人中,左室收缩功能正常者达55%,而仅有左室舒张功能不全,且左室收缩功能正常或轻度减退者高达80%.其中女性左室收缩功能正常者尤较男性多见(67%∶42%,P＜0.001),表现为单纯左室舒张功能不良.而在左室收缩功能正常的CHF老人,常伴有左室内径较小、左室收缩末期室壁张力较低、左室重量较轻、左室收缩末期室壁厚度增加,而左室射血分数正常或仅轻度降低. 讨论以上结果提示,在老年人群中,CHF年发病率相对较高,且随年龄而增加,多数左室收缩功能正常,仅有左室舒张功能障碍,尤其是在高龄女性,亦即高龄女性左室舒张功能不全性CHF更为常见.对此,临床上更应拟出合理的防范措施,来正确诊治老年CHF综合征. (袁志敏摘)     

A humanised tissue‐engineered bone model allows species‐specific breast cancer‐related bone metastasis in vivo

Bone metastases frequently occur in the advanced stages of breast cancer. At this stage, the disease is deemed incurable. To date, the mechanisms of breast cancer‐related metastasis to bone are poorly understood. This may be attributed to the lack of appropriate animal models to investigate the complex cancer cell–bone interactions. In this study, two established tissue‐engineered bone constructs (TEBCs) were applied to a breast cancer‐related metastasis model. A cylindrical medical‐grade polycaprolactone‐tricalcium phosphate scaffold produced by fused deposition modelling (scaffold 1) was compared with a tubular calcium phosphate‐coated polycaprolactone scaffold fabricated by solution electrospinning (scaffold 2) for their potential to generate ectopic humanised bone in NOD/SCID mice. While scaffold 1 was found not suitable to generate a sufficient amount of ectopic bone tissue due to poor ectopic integration, scaffold 2 showed excellent integration into the host tissue, leading to bone formation. To mimic breast cancer cell colonisation to the bone, MDA‐MB‐231, SUM1315, and MDA‐MB‐231BO breast cancer cells were cultured in polyethylene glycol‐based hydrogels and implanted adjacent to the TEBCs. Histological analysis indicated that the breast cancer cells induced an osteoclastic reaction in the TEBCs, demonstrating analogies to breast cancer‐related bone metastasis seen in patients.     

Permanent pacemaker use after cardiac transplantation: completing the audit cycle.

OBJECTIVE: To determine the effects of delaying permanent pacemaker implantation in cardiac transplant recipients from less than tree weeks to three weeks or more post transplantation-a change prompted by an earlier audit. DESIGN: Retrospective review of resting 12 lead electrocardiograms and prospective 24 hour ambulatory electrocardiograms. Comparison of pacemaker usage before (period 1) and after (period 2) the policy change in November 1990. SETTING: Outpatient department, supra-regional cardiopulmonary transplant unit. PATIENTS: All 30 consecutive orthotopic cardiac transplant recipients who received a permanent pacemaker within one month of transplantation between May 1985 and August 1995. MAIN OUTCOME MEASURES: Presence of pacing on the 12 lead electrocardiogram and during 24 hour ambulatory electro-cardiogram monitoring (pacemaker programmed to 50 beats per minute). RESULTS: 16/152 (10.5%) cardiac transplant recipients received permanent pacemakers in period 1 compared with 14/180 (7.8%) in period 2 (P = NS). Evidence of pacing was seen on 12 lead electrocardiograms at three months in 37.5% recipients in period 1 compared with 78.6% in period 2 (P = 0.03). At six months pacemaker usage had declined to 18.8% in period 1 and 35.7% in period 2 and at three years to 13.3% in period 1 and 40% in period 2 (P = NS for both). 21% patients in period 1 paced on ambulatory 24 hour monitoring compared with 38.5% in period 2 (P = NS). CONCLUSIONS: Delaying permanent pacemaker implantation to three weeks or more after cardiac transplantation reduced the proportion of permanent pacemaker implantations, slightly but not significantly. There was a significant increase in permanent pacemaker usage at three months post transplantation with trends towards increased usage at later times, suggesting more appropriate selection of patients for permanent pacing.