Ultrastructure changes associated with brain death in the human donor heart

Abstract Electromicroscopic examinations were carried out on 30 myocardial biopsies taken from 22 human donor hearts immediately after excision (prestorage) or immediately before transplantation (post-storage). All electron micrographs were independently examined by two morphologists. Eleven structures were examined in each micrograph, and each structure was scored according to the degree of injury. A good interobserver correlation was obtained in 84 % of the structures scored. In the prestorage left ventricular biopsies ( n = 11), approximately 20 %-25 % showed moderate to severe ultrastructural injury. The ultrastructural injury observed in the poststorage left ventricular biopsies ( n = 15) was no different from that in the prestorage group, particularly injury to the sarcomere and mitochondria. A similar degree and pattern of injury was seen in the right ventricle ( n = 4). There was no evidence that an ischemic storage period of less than 6 h increased the degree of injury seen. However, there was a higher incidence of moderate to severe injury in those hearts excised from donors initially dependent on high inotropic support.     

Effect of systemic zinc administration on delayed neuronal death in the gerbil hippocampus

The divalent cation zinc has been reported to possess several physiological properties such as blocking apoptotic cell death through an inhibitory effect on Ca²⁺-Mg²⁺ endonuclease activity, or modulating the neurotoxicity via glutamate receptor subtypes. In the present study, we investigated the effect of peripherally injected zinc on delayed neuronal death seen in the hippocampus after transient global ischemia, in order to elucidate a possible beneficial role on zinc in ischemic neuronal cell death. Forty-five adult Mongolian gerbils of both sexes underwent transient bilateral clipping of the common carotid arteries for 3 min. In the pretreated animals, ZnCl₂ (20 mg/kg) was injected subcutaneously once, 1 h before ischemia (superacute group; n=6) or twice at 24 and 48 h before ischemia (subacute group; n=14). Histological survey was carried out 3 days later by in situ DNA fragmentation method and 4 days later by hematoxylin-eosin staining by semiquantatively counting dead neurons in the CA1 sector. Subacute zinc pre-administration significantly reduced the nuclear damage and subsequent neuronal death; however, superacutely pre-administered zinc did not protect hippocampal neurons against ischemia but it did not aggravate the effect of ischemia, either. The present study suggested that transfer of exogenous zinc into the intracellular space is required for neuroprotection, presumably via the anti-endonuclease activity.     

Successful Liver and Kidney Transplantation From Cadaveric Donors With Left-Sided Bacterial Endocarditis

Bacterial infections are frequent in cadaveric organ donors and can be transmitted to the transplantation recipient, which could have devastating consequences for the recipients if adequate preventive measures are not adopted.
From the 355 consecutive brain dead cadaveric organ donors procured at our center in the last four years, 2000–2003, four of them (1.1%) had bacterial endocarditis as cause of death. The bacteria responsible for the endocarditis were Staphylococcus epidermidis, coagulase-negative Staphylococcus , Staphylococcus hominis and Streptococcus viridans , respectively. We performed five kidney and two liver transplantations on seven recipients. All donors and recipients received antibiotic treatment against the germ causing the respective endocarditis.
Infection by the bacteria responsible for the endocarditis in the respective donors was not transmitted to any of the recipients. Six of the seven recipients were alive with normal-functioning grafts after between 13 and 24 months' follow-up. Transplantectomy was performed on one kidney recipient due to thrombosis of the renal vein of the graft not related to the endocarditis.
Liver and kidney transplantation from donors dying from bacterial endocarditis can be performed without causing the transmission of infection to the recipient or the dysfunction of the graft.     

The Hemodynamic Mechanisms of Lung Injury and Systemic Inflammatory Response Following Brain Death in the Transplant Donor

Brain-dead donors are the major source of lungs for transplantation. Brain death is characterized by two hemodynamic phases. Initially, massive sympathetic discharge results in a hypertensive crisis. This is followed by neurogenic hypotension. Up-regulation of pro-inflammatory mediators occurs in all organs and lung injury develops; this can adversely affect graft function post-transplantation. The mechanisms of the systemic and lung inflammation are unknown. We hypothesized that the hemodynamic changes are responsible for these inflammatory phenomena. Brain death was induced by intra-cranial balloon inflation in rats. This resulted in hypertensive crisis, followed by hypotension. There was a significant increase in blood neutrophil CD11b/CD18 expression and pro-inflammatory cytokine levels in serum and bronchoalveolar lavage, compared with control animals. Rupture of the capillary-alveolar membrane was demonstrated by electron microscopy. Elimination of the hypertensive response by α-adrenergic antagonist pre-treatment prevented inflammatory lung injury, reduced the systemic inflammatory markers and preserved capillary-alveolar membrane integrity. Correction of the neurogenic hypotension with noradrenaline ameliorated the systemic inflammatory response and improved oxygenation. We conclude that the sympathetic discharge triggers systemic and lung inflammation, which can be further enhanced by neurogenic hypotension. Management of the brain-dead donor with early anti-inflammatory treatment and vasoconstrictors is warranted.     

Segmental Liver Transplantation from Non-Heart Beating Donors—An Early Experience with Implications for the Future

We report our experience of pediatric liver transplantation with partial grafts from non-heart beating donors (NHBD). Controlled donors less than 40 years of age with a warm ischemia time (WI) of less than 30 min were considered for pediatric recipients. Death was declared 5 min after asystole. A super-rapid recovery technique with aortic and portal perfusion was utilized. Mean donor age was 29 years and WI 14.6 min (range 11–18). Seven children, mean age 4.9 years (0.7–11), median weight 20 kg (8.4–53) received NHBD segmental liver grafts. Diagnoses included seronegative hepatitis, neonatal sclerosing cholangitis, familial intrahepatic cholestasis, hepatoblastoma, primary hyperoxaluria and factor VII deficiency (n = 2).The grafts included four reduced and one split left lateral segments, one left lobe and one right auxiliary graft. Mean cold ischemia was 7.3 h (6.2–8.8). Complications included one pleural effusion and one biliary collection drained percutaneously. At 20 months (10–36) follow-up all children are alive and well with functioning grafts.
Donation after cardiac death is a significant source of liver grafts for adults and children with careful donor selection and short cold ischemic times.     

深低温冷冻肌腱细胞活性的研究

目的研究深低温冷冻方法对肌腱细胞活性的影响,比较程序性降温和普通深低温冷冻法对腱细胞活性的影响.方法纯种SD大鼠24只（出生21 d）,随机分为3组,取双侧跟腱.新鲜肌腱对照组（A）,常规深低温冷冻组（B）,程序性降温深低温冷冻组（C）.采用相同的方法对3组肌腱细胞进行细胞培养.相差显微镜观察原代和传代后细胞的生长,绘制细胞的生长曲线,考察细胞的活性;对细胞进行成纤维细胞染色、胶原染色和对细胞进行形态观察（扫描电镜）;水解法定量分析细胞培养基中羟脯氨酸浓度的变化,检测细胞合成胶原的能力.结果原代细胞培养时A组细胞的生长速度快于B组和C组（P＜0.01）,C组细胞的生长速度快于B组（P＜0.01）,这种生长速度的差异在细胞传代后消失.细胞的形态学和组织学符合成纤维细胞形态.3组细胞培养基中羟脯氨酸浓度变化的差异无统计意义（P＞0.05）.结论经深低温冷冻处理的肌腱中仍存在具有活性的腱细胞,但数量显著少于新鲜肌腱中活细胞的数量.应用计算机控制程序性慢速降温方法处理的肌腱其活细胞的数量有所提高,但仍低于新鲜肌腱中活细胞的数量.     

Cigarette smoke toxicants alter growth and survival of cultured mammalian cells.

Our purpose was to determine the effects of six cigarette toxicants (pyridine, nicotine, 2-ethylpyridine, 3-ethylpyridine, p-cresol, and pyrazine) on three types of cultured mammalian cells (human umbilical vein endothelial cells [HUVECs], human microvascular endothelial cells [HMVECs], and NIH 3T3 cells) using a cell proliferation/survival assay. Synchronized cells were cultured in proliferation or survival medium containing various doses (10(-18)M-10(-2)M) of the tested chemicals. After 48 h, cells were counted using a hemacytometer. The no observable adverse effect level (NOAEL), lowest observable adverse effect level (LOAEL), and the efficacy were determined for each compound in the cell proliferation and survival assays. Pyridine and p-cresol did not show significant effects with any cell types, except at high doses. Derivitization of the pyridine ring altered its potency, especially when an ethyl group or nitrogen was added. In survival medium, nicotine stimulated proliferation of all three cell types at doses found in smoker's serum (10(-8)M-10(-7)M). For HUVEC and HMVEC, 2-ethylpyridine, 3-ethylpyridine, and pyrazine inhibited proliferation in proliferation medium and induced cell death in survival medium at attomolar and femtomolar doses. All chemicals, except pyridine and pyrazine, stimulated NIH 3T3 cell proliferation at low doses and induced cell death at high doses. LOAELs and efficacies revealed that endothelial cells from a developing organ (umbilical cord) were more sensitive to these chemicals than endothelial cells from an adult organ (lung). 3-Ethylpyridine and pyrazine, which induced cell death at low doses, are added to consumer products and should be subjected to further toxicological testing.     

Fifteen-year follow-up of 92 hospitalized adults with Down's syndrome: incidence of cognitive decline, its relationship to age and neuropathology

Background The clinical and neuropathological features associated with dementia in Down’s syndrome (DS) are not well established. Aims To examine clinico‐pathological correlations and the incidence of cognitive decline in a cohort of adults with DS. Method A total of 92 hospitalized persons with DS were followed up from 1985 to December 2000. At outset, 87 participants were dementia‐free, with a median age of 38 years. Assessments included the Prudhoe Cognitive Function Test (PCFT) and the Adaptive Behavior Scale (ABS), to measure cognitive and behavioural deterioration. Dementia was diagnosed from case records and caregivers’ reports. Results Eighteen (21%) patients developed dementia during follow‐up, with a median age of onset 55.5 years (range 45–74). The PCFT demonstrated cognitive decline among those with a less severe intellectual disability (mild and moderate) but not among the profoundly disabled people (severe and profound). Clinical dementia was associated with neuropathological features of Alzheimer’s disease, and correlated with neocortical neurofibrillary tangle densities. At the age of 60 years and above, a little more than 50% of patients still alive had clinical evidence of dementia. Conclusions Clinical dementia associated with measurable cognitive and functional decline is frequent in people with DS after middle age, and can be readily diagnosed among less severely intellectually disabled persons using measures of cognitive function such as the PCFT and behavioural scales such as the ABS. In the more profoundly disabled people, the diagnosis of dementia is facilitated by the use of behavioural and neurological criteria. In this study, the largest prospective DS series including neuropathology on deceased patients, the density of neurofibrillary tangles related more closely to the dementia of DS than senile plaques. In people with DS surviving to middle and old age, the development of dementia of Alzheimer type is frequent but not inevitable, and some people with DS reach old age without clinical features of dementia.