Is zinc the link between compromises of brain perfusion (excitotoxicity) and Alzheimer's disease?

Prior brain injury is a major risk factor in the development of Alzheimer's disease. This is true for traumatic brain injury, stroke or ischemic brain injury, and (more speculatively) for brain injury resulting from the hypo-perfusion-reperfusion in cardiac arrest or cardiac bypass surgery and even hypo- or hypertension. Here we propose that the release of excess, toxic, "floods" of free zinc into the brain that occurs during and after all excitotoxic brain injury is a key factor that sets the stage for the later development of Alzheimer's disease. Rapid and aggressive administration of zinc buffering compounds to patients suffering brain injury may therefore not only ameliorate the acute injury but might also reduce the risk of subsequent development of Alzheimer's disease.     

Apomorphine-induced alterations in striatal and substantia nigra pars reticulata glutamate following unilateral loss of striatal dopamine

We have reported time-dependent changes in extracellular glutamate within the striatum at 1 and 3 months following a unilateral lesion of the nigrostriatal pathway using the neurotoxin, 6-hydroxydopamine (6-OHDA) (Meshul, C.K., Emre, N., Nakamura, C.M., Allen, C., Donohue, M.K., Buckman, J.F., 1999. Time-dependent changes in striatal glutamate synapses following a 6-hydroxydopamine lesion. Neurosci. 88, 1-16.). The aim of the present study was to determine the effects of such a lesion on glutamate within the substantia nigra pars reticulata (SN-PR) and the effect of subchronic administration of the dopamine D-1/D-2 agonist, apomorphine, on extracellular glutamate within both the striatum and the SN-PR using in vivo microdialysis. One month after the lesion, there is an increase in extracellular glutamate within the striatum and apomorphine treatment leads to a further increase. Within the SN-PR, a loss of striatal dopamine leads to a decrease in extracellular glutamate, while apomorphine treatment leads to a further decrease in nigral glutamate. Three months after a 6-OHDA lesion, there is a decrease in extracellular striatal glutamate, with apomorphine administration leading to essentially no further change in glutamate. The loss of striatal dopamine increased extracellular glutamate within the SN-PR while apomorphine administration resulted in a decrease in extracellular glutamate back to the value observed in the control group. The data suggests that the increase in striatal glutamate 1 month following a 6-OHDA lesion alone or following subchronic apomorphine is consistent with the hypothesis that a decrease in glutamate within the SN-PR leads to activation of the thalamo-cortico-striatal pathway. The decrease in striatal glutamate 3 months after a nigrostriatal lesion is also consistent with the observed increase in extracellular glutamate within the SN-PR, thus leading to a decrease in output of the thalamo-cortico-striatal pathway.     

Using an eclectic model to educate students about cultural influences on the nurse-patient relationship

This article describes how the concepts of cultural awareness, cultural sensitivity, and cultural competence are integrated into the nursing curriculum at Lehman College, City University of New York. A culturally diverse student population engaged in lectures, classroom exercises, and clinical experiences in order to learn the ideas and imperatives of cultural diversity in nursing care. The exercises were problem-based learning experiences guided by a university-developed model for teaching students to understand cultural diversity. The model is derived from Leininger's comparative cultural caring model and Paterson and Zderad's humanistic nursing model. By observing differences and similarities among diverse cultures, students learned that the assignment of cultural attributes is an inexact process and should be organized as hints rather than as certainties. Students also learned the importance of integrating cultural awareness, cultural sensitivity, and cultural competence into their nursing care.     

Evaluation of the Sheffield system for identifying children at risk from unexpected death in infancy. Results from Birmingham and Newcastle upon Tyne

The "at birth" system which is used in Sheffield to identify children likely to die unexpectedly in infancy, was tested retrospectively in Birmingham (83 cases) and in Newcastle upon Tyne (56 cases). The discrimination between cases and age-matched controls was poor in both cities. Analysis of the 8 factors used in the system showed that only 2 maintained significant case/control differences in Birmingham and Newcastle. Further investigation showed that other factors from maternity records showed significant case/control differences in these cities. Although the system used in Sheffield would not be of use in a prospective prevention programme in either Newcastle or Birmingham, the possibility of evolving an "at risk" system which might apply more widely is discussed.     

脾切除对结直肠癌切除术后的影响：一项多中心、嵌入式、配对队列研究

目的探讨医源性脾脏损伤脾切除对结直肠癌切除患者术后长期生存的影响。方法对1990年1月1日至1999年12月31日10年间行结直肠癌手术切除并附带脾切除患者进行病例配对回顾研究。分析患者年龄、性别、依据美国麻醉学医师协会（ASA）标准评估的身体状况、疾病分期、手术类型及预后等资料。配对病例来自同一医疗中心，性别、年龄、疾病分期及手术类型完全相同。手术附带脾切除患者为试验组，未切脾者为对照组。结果55例患者行医源性脾切除术，对照组在年龄、性别、身体状况、疾病分期及手术类型上与之匹配。随访时间（从手术开始到患者死亡或者最后一次随访1为2～205个月（中位随访时间为43个月）。Cox比例危险度模型进行Kaplan-Meier法生存分析发现两组间差异有显著性意义，不切除脾脏对患者生存有利（危险度1．8，95％可信区间为1-3．3，P=0．0399），未切脾组与切脾组5年生存率分别为70％和47％，10年生存率分别为55％和38％。结论结直肠癌患者在行结肠或直肠切除时，因医源性脾脏损伤而切除脾脏者，预后较差。     

The mineralization of elastic fibers and alterations of extracellular matrix in pseudoxanthoma elasticum. Ultrastructure, immunocytochemistry, and X-ray analysis

Histologic paraffin sections of pseudoxanthoma elasticum (PXE)-involved skin of forearm and axilla were used for histochemistry and immunohistochemical and analytical electron microscopy to study the progressive mineralization in the dermis of patients with PXE. The von Kossa technique identified mineral deposits throughout the reticular PXE dermis. X-ray analysis revealed patterns of calcium and phosphorus deposition in the von Kossa-positive areas, and the immunohistochemical staining using monoclonal antibodies identified increased chondroitin-6-sulfate in these areas when compared with normal skin. Scanning transmission electron microscopy observation combined with X-ray dot mapping show calcium and phosphorus to be codistributed within the mineralized area. This study confirms by new methods the increase in chondroitin-6-sulfate, alterations in elastin and collagen, and a high calcium and phosphorus elemental distribution matching the mineralized area in the PXE dermis.     

Opossum adrenal medulla: I. Postnatal development and normal anatomy

The anatomy and histology of the adrenal gland in the adult opossum were found to be typical for mammals. The development of the adrenal medulla was also found to follow the typical mammalian pattern. Primitive sympathetic cells were found in both intra- and extra-adrenal locations in the newborn at a time when chromaffin precursor cells were migrating to the adrenal anlage. Pheochromoblasts first appeared within the forming medulla where at a later stage chromaffin cells could be observed forming columns of cells between adjacent sinusoids. Unlike in other mammals, much of this development takes place postnatally when the neonate is in the mother's marsupium. The value of the developing opossum adrenal medulla as an experimental model is stressed, since a significant amount of development takes place in an environment that is accessible to experimental manipulation.