BACKGROUND & AIMS: :A 29-year-old man was admitted to our institution 10 days after he had undergone an urgent exploratory laparotomy at a local army hospital after a terrorist bombing attack. On admission, deep second-degree and third-degree burns involving 25% of the upper and lower extremities were present, together with a 25 x 10-cm abdominal full-thickness blast injury defect on the left side, an infected eviscerated midline incision, and a colostomy on the right side of the abdomen. The patient underwent a second laparotomy, at which time the intraabdominal abscess was drained, and the abdominal cavity was irrigated with saline. A jejunal perforation was found and sutured. The abdominal cavity was left open and covered with a Bogota bag for temporary closure. On postburn day 18, the patient underwent débridment and grafting of the third-degree burns to the left and right arm and right lower extremities. After several débridment sessions (postburn days 16, 18, 20, 22, and 24), an abdominal skin release and reapproximation were performed (postburn day 26). On postburn day 36, split-thickness skin grafts were placed directly on the granulated tissue of the intestines and on a defect in the left flank and iliac regions. Postoperatively, the patient did well. He was discharged on postburn day 78 with all wounds well healed. In our opinion, temporary closure followed by direct application of meshed split-thickness skin grafts to exposed abdominal viscera represents a simple method of reconstruction that can be safely performed, with minimal risk, on critically ill patients.

背景与目标： : 一名29岁的男子在恐怖爆炸袭击后在当地一家军队医院接受紧急剖腹探查术10天后被送入我们的机构。入院时，出现了涉及上下肢25% 的深二度和三度烧伤，左侧有25x10 cm的腹部全层爆炸伤缺损，感染的内脏中线切口，以及腹部右侧的结肠造口术。患者接受了第二次剖腹手术，此时引流了腹腔内脓肿，并用盐水冲洗了腹腔。发现空肠穿孔并缝合。腹腔保持开放状态，并用波哥大袋覆盖，以暂时关闭。在烧伤后第18天，患者接受了三度烧伤的移植，并将其移植到左，右臂和右下肢。经过几次缓解 (烧伤后第16、18、20、22和24天) 后，进行了腹部皮肤释放和重新逼近 (烧伤后第26天)。在烧伤后的第36天，将厚度分开的皮肤移植物直接放置在肠的颗粒状组织以及左侧和ili区的缺损处。术后，患者表现良好。他在烧伤后第78天出院，所有伤口均愈合良好。在我们看来，暂时封闭，然后直接将网状厚度的皮肤移植物应用到暴露的腹部内脏上，代表了一种简单的重建方法，可以对危重病人安全地进行，风险最小。

BACKGROUND & AIMS: OBJECTIVE:To investigate renal preservation by a novel method of perfusion using an oxygenated perfluorocarbon (PFC) emulsion via retrograde access to the kidney, as preserving renal function during urological surgery has been elusive, and the recognized technique of nephron-sparing surgery has increased its application and practice in modern urology. MATERIALS AND METHODS:After institutional review and approval, 30 New Zealand White rabbits were studied. In a solitary kidney model, each rabbit had the ureter catheterized before 40 min of renal artery occlusion. Each rabbit was randomized to one retrograde perfusion group, i.e. sham, normothermic PFC, chilled PFC, normothermic saline, and chilled saline. The rabbits were maintained for 2 weeks, during which renal function, urine output, systemic blood gases, weight and serum creatinine level were measured. After death, the kidneys were individually examined and graded by one renal pathologist unaware of the treatment. RESULTS:The rabbits treated with retrograde PFC perfusion (normothermic and chilled) had less change in their creatinine clearance, at 3.6 and 4.0 mL/min per kg, than the sham group, at 7.8 mL/min per kg, while also having significantly higher systemic venous oxygenation, at 26.3 and 10.0 mmHg, than the sham group, at 0.2 mmHg. Normothermic and chilled perfusion with PFC was also associated with less histological evidence of ischaemic damage, with mean (sd) scores of 13.0 (13.5) and 8.7 (4.5), respectively, than in the sham group, at 33.3 (16.8), while favourably matching the contralateral control kidney group, at 5.5 (2.3). The rabbits treated with saline retrograde perfusion also had better outcomes than the sham cohort. There were no adverse effects in any of the study arms or with the use of PFC. CONCLUSION:Retrograde oxygen delivery to the kidney through the urinary collecting system was successful in this pilot study. Renal function, laboratory and histological data indicate a trend towards renal preservation and even systemic oxygenation in the experimental groups compared with the sham rabbits, with no adverse effects attributed to this technique.

背景与目标：

BACKGROUND & AIMS: BACKGROUND:Despite increasing numbers of morbidly obese patients admitted to acute care facilities for surgery or treatment of nonsurgical conditions, there is little evidence of the problems nurses face in providing care to these patients. Anecdotal evidence suggests that the care of these patients is more demanding than the care of nonobese patients. The objective of this study was to describe nurses' perceptions of the challenges that they face when caring for morbidly obese patients. METHODS:Focus groups of nurses from a tertiary care facility were convened. A trained facilitator posed questions to the group concerning various aspects of care for morbidly obese patients. Comments of respondents were categorized using NVIVO software. RESULTS:Nurses reported concerns about the increased staffing needs required for care of these patients and the particular challenges of the physical care. Concerns also included the availability, placement, and use of specialized equipment. Room size and the absence of some equipment were also problematic. Finally, nurses perceived safety issues, both for themselves and their patients. CONCLUSIONS:Morbidly obese patients in the acute care setting require specialized nursing care in terms of techniques, levels of staffing required, and the use of specialized equipment.

背景与目标：

BACKGROUND & AIMS: :Endomyocardial specimens were obtained from 7 patients with acute myocarditis. Immunohistochemical examination of the mononuclear infiltrate showed mainly cytotoxic T lymphocytes and natural killer cells. Perforin (a pore-forming protein found in cytotoxic lymphocytes) was identified in this myocardial lymphocytic infiltrate and electron microscopy showed myocardial cell damage that may have been associated with these perforin containing lymphocytes. The results indicate that in acute idiopathic and viral myocarditis, myocardial damage may be due to the action of perforin-secreting lymphocytes.

背景与目标： : 从7例急性心肌炎患者中获得心内膜心肌标本。对单核浸润的免疫组织化学检查显示主要是细胞毒性T淋巴细胞和自然杀伤细胞。在这种心肌淋巴细胞浸润中鉴定出穿孔素 (一种在细胞毒性淋巴细胞中发现的成孔蛋白)，电子显微镜显示心肌细胞损伤可能与这些含有穿孔素的淋巴细胞有关。结果表明，在急性特发性和病毒性心肌炎中，心肌损伤可能是由于穿孔素分泌淋巴细胞的作用所致。

BACKGROUND & AIMS: BACKGROUND:Pulmonary surfactant dysfunction may contribute to the development of ventilator induced lung injury (VILI). Tracheal gas insufflation (TGI) is a technique in which fresh gas is introduced into the trachea and augment ventilation by reducing the dead space of ventilatory system, reducing ventilatory pressures and tidal volume (V(T)) while maintaining constant partial arterial CO2 pressure (PaCO(2)). We hypothesised that TGI limited peak inspiratory pressure (PIP) and V(T) and would minimize conventional mechanical ventilation (CMV) induced pulmonary surfactant dysfunction and thereby attenuate VILI in rabbits with acute lung injury (ALI). METHODS:ALI was induced by intratracheal administration of lipopolysaccharide in anaesthetized, ventilated healthy adult rabbits randomly assigned to continuous TGI at 0.5 L/min (TGI group) or CMV group (n = 8 for each group), and subsequently ventilated with limited PIP and V(T) to maintain PaCO(2) within 35 to 45 mmHg for 4 hours. Physiological dead space to V(T) ratio (V(D)/V(T)), dynamic respiratory compliance (Cdyn) and partial arterial O(2) pressure (PaO(2)) were monitored. After ventilation, lungs were analysed for total phospholipids (TPL), total proteins (TP), pulmonary surfactant small to large aggregates ratio (SA/LA) in bronchoalveolar lavage fluid (BALF) and for determination of alveolar volume density (V(V)), myeloperoxidase and interleukin (IL)-8. RESULTS:TGI resulted in significant (P < 0.05 or P < 0.01) decrease in PIP [(22.4 +/- 1.8) cmH2O vs (29.5 +/- 1.1) cmH2O], V(T) [(6.9 +/- 1.3) ml/kg vs (9.8 +/- 1.11) ml/kg], V(D)/V(T) [(32 +/- 5)% vs (46 +/- 2)%], TP [(109 +/- 22) mg/kg vs (187 +/- 25) mg/kg], SA/LA (2.5 +/- 0.4 vs 5.4 +/- 0.7), myeloperoxidase [(6.2 +/- 0.5) U/g tissue vs (12.3 +/- 0.8) U/g tissue] and IL-8 [(987 +/- 106) ng/g tissue vs (24 +/- 3) mN/m] of BALF, and significant (P < 0.05) increase in Cdyn [(0.47 +/- 0.02) ml.cmH2O(-1).kg(-1) vs (0.31 +/- 0.02) ml.cmH2O(-1).kg(-1)], PaO(2) [(175 +/- 24) mmHg vs (135 +/- 26) mmHg], TPL/TP (52 +/- 8 vs 33 +/- 11) and Vv (0.65 +/- 0.05 vs 0.44 +/- 0.07) as compared with CMV. CONCLUSIONS:In this animal model of ALI, TGI decreased ventilatory requirements (PIP, V(T) and V(D)/V(T)), resulted in more favourable alveolar pulmonary surfactant composition and function and less severity of lung injury than CMV. TGI in combination with pressure limited ventilation may be a lung protective strategy for ALI.

背景与目标：

BACKGROUND & AIMS: :Acute purulent meningitis as a manifestation of cerebral cysticercosis is uncommon. We report two children aged 12 months and 3 years who presented with clinical signs of acute meningitis and whose initial cerebrospinal fluid (CSF), except for negative culture, was typical of purulent meningitis. However, eosinophils were present in subsequent examinations of the CSF and the haemagglutination titre for cysticercus rose. Praziquantel was given to both children with dramatic improvement in clinical and CSF findings.

背景与目标： : 急性化脓性脑膜炎作为脑囊虫病的表现并不常见。我们报告了两名年龄分别为12个月和3岁的儿童，他们表现出急性脑膜炎的临床症状，除阴性培养外，其初始脑脊液 (CSF) 是化脓性脑膜炎的典型表现。然而，在随后的CSF检查中存在嗜酸性粒细胞，并且囊尾蚴的血凝滴度上升。对两名临床和CSF表现均显着改善的儿童均给予吡喹酮。

BACKGROUND & AIMS: :Acute kidney injury is followed by regeneration of damaged renal tubular epithelial cells. The purpose of this study was to test the hypothesis that renal stem cells exist in the adult kidney and participate in the repair process. A unique population of cells that behave in a manner that is consistent with a renal stem cell were isolated from rat kidneys and were termed multipotent renal progenitor cells (MRPC). Features of these cells include spindle-shaped morphology; self-renewal for >200 population doublings without evidence for senescence; normal karyotype and DNA analysis; and expression of vimentin, CD90 (thy1.1), Pax-2, and Oct4 but not cytokeratin, MHC class I or II, or other markers of more differentiated cells. MRPC exhibit plasticity that is demonstrated by the ability of the cells to be induced to express endothelial, hepatocyte, and neural markers by reverse transcriptase-PCR and immunohistochemistry. The cells can differentiate into renal tubules when injected under the capsule of an uninjured kidney or intra-arterially after renal ischemia-reperfusion injury. Oct4 expression was seen in some tubular cells in the adult kidney, suggesting these cells may be candidate renal stem cells. It is proposed that MRPC participate in the regenerative response of the kidney to acute injury.

背景与目标： : 急性肾损伤后，受损的肾小管上皮细胞再生。目的检验肾干细胞存在于成人肾脏并参与修复过程的假说。从大鼠肾脏中分离出一种独特的细胞群，其行为方式与肾干细胞一致，被称为多能肾祖细胞 (MRPC)。这些细胞的特征包括梭形形态;> 200种群倍增的自我更新，没有衰老的证据; 正常的核型和DNA分析; 波形蛋白，CD90 (thy1.1)，Pax-2和10月4的表达，而不是细胞角蛋白，MHC I或II类，或更多分化细胞的其他标记。MRPC表现出可塑性，通过逆转录酶PCR和免疫组织化学诱导细胞表达内皮，肝细胞和神经标志物的能力证明了这种可塑性。当在未受伤的肾脏的胶囊下注射或在肾缺血再灌注损伤后动脉内注射时，细胞可以分化为肾小管。在成人肾脏的某些肾小管细胞中观察到10月4的表达，表明这些细胞可能是候选的肾干细胞。建议MRPC参与肾脏对急性损伤的再生反应。

BACKGROUND & AIMS: How an increase in blood pressure, in and of itself, induces hypertensive nephrosclerosis is unclear. In an earlier study we found that leukocyte infiltration, proximal tubular cell proliferation, matrix deposition and interstitial fibrosis occur in the unclipped kidney of 2 K 1 C Goldblatt hypertensive rats. In this study we tested the hypothesis that the cell surface adhesion molecule ICAM-1 is expressed on the vascular endothelium and tubular epithelium of unclipped kidneys at 4 weeks. As a positive control, we examined the clipped kidney as well. We found that systolic blood pressure was significantly elevated in renovascular hypertensive rats compared to sham-operated controls after 4 weeks (198 +/- 5 mmHg vs 121 +/- 2 mmHg, P < 0.001). Furthermore, quantitative (densitometry) measurements showed that ICAM-1 expression on vascular endothelium and on tubular cells was significantly increased in unclipped kidneys compared to controls (P < 0.05). The same was true for monocyte and granulocyte infiltration (P < 0.05). These same variables were even more prominent in the clipped kidneys, compared to unclipped and control kidneys (P < 0.05). Our data show that ICAM-1 is expressed in unclipped kidneys exposed to hypertension as well as in clipped kidneys exposed to ischemia. We suggest that mechanical injury induced by increased blood pressure is responsible for an inflammatory adhesion molecule-mediated response and concomitant renal injury.

背景与目标： 目前尚不清楚血压本身的升高如何引起高血压肾硬化。在较早的研究中，我们发现2 K 1 C Goldblatt高血压大鼠的未夹肾中发生白细胞浸润，近端肾小管细胞增殖，基质沉积和间质纤维化。在这项研究中，我们测试了以下假设: 细胞表面粘附分子ICAM-1在4周时在未夹住的肾脏的血管内皮和肾小管上皮上表达。作为阳性对照，我们也检查了截断的肾脏。我们发现，与假手术对照组相比，肾血管性高血压大鼠的收缩压在4周后显着升高 (198/- 5 mmHg vs 121/- 2 mmHg，P <0.001)。此外，定量 (密度测定法) 测量显示，与对照组相比，未夹住的肾脏在血管内皮和肾小管细胞上的ICAM-1表达显着增加 (P <0.05)。单核细胞和粒细胞浸润也是如此 (P <0.05)。与未夹肾和对照肾相比，这些相同的变量在夹肾中更为突出 (P <0.05)。我们的数据显示，ICAM-1在暴露于高血压的未夹肾以及暴露于缺血的夹肾中表达。我们建议由血压升高引起的机械损伤是炎症粘附分子介导的反应和伴随的肾损伤的原因。

BACKGROUND & AIMS: :This pilot study investigated adolescents with well-documented childhood lead burdens to determine the relationship between lead and unintentional injury. Adolescents completed a self-administered injury questionnaire. Results demonstrated that elevated childhood blood lead concentrations were significantly related to injury variables. Further study is necessary to understand adolescent health and safety implications.

背景与目标： : 这项初步研究调查了有充分记录的儿童铅负担的青少年，以确定铅与意外伤害之间的关系。青少年完成了一份自我管理的伤害问卷。结果表明，儿童血铅浓度升高与损伤变量显着相关。为了了解青少年健康和安全的影响，有必要进行进一步的研究。

BACKGROUND & AIMS: OBJECTIVE:Accumulating findings suggest that in acute myeloid leukemia (AML) patients, proinflammatory cytokines and growth factors play important roles in the proliferation and survival of AML cells in an autocrine and paracrine manner, leading to deterioration of AML. JTE-607 is a multiple cytokine inhibitor that potently suppresses production of proinflammatory cytokines. In the present study, we investigated the potency of JTE-607 as an antileukemic agent by exploiting a SCID mouse acute leukemia model. METHODS:SCID mice injected with anti-asialo-GM1 antibody were exposed to sublethal total-body irradiation at a dose of 3 Gy and then inoculated intravenously with AML cells. JTE-607 was administered using osmotic minipumps. The effects of JTE-607 on mouse survival time, human interleukin (IL)-8 levels in mouse plasma, and proportion of human CD45(+) cells in the bone marrow were studied. RESULTS:The survival time of the mice was strictly dependent on the number of U-937 cells proliferating in vivo. Administration of JTE-607 during the initial 7 days significantly prolonged survival of the mice, suggesting killing activity of JTE-607 against AML cells in vivo. Delayed administration of JTE-607 also prolonged the survival of mice bearing established leukemia with an effect comparable to the maximum tolerable dose of cytarabine. Flow cytometer analysis of bone marrow cells revealed decreased number of human CD45(+) cells. Human IL-8 level was also reduced by JTE-607. CONCLUSION:Our results indicate that JTE-607 has potential to be a new class of antileukemic drug that exerts inhibitory activities against both the proliferation and proinflammatory cytokine production of AML cells.

背景与目标：

BACKGROUND & AIMS: The CD56 antigen is normally expressed on natural-killer cells but has additionally been shown to be present on a variety of hematologic malignancies, including a subset of acute myelogenous leukemia (AML). There is disagreement, however, about its prognostic significance and its association with specific cytogenetic abnormalities. All clinical samples from June 1994, through September 1995, with increased myeloblasts were analyzed by multiparameter flow cytometry for anomalous expression of CD56. Patients with CD56+ blast cells were selected, and morphologic review was performed. Clinical information was obtained, and cytogenetic data were reviewed. Southern blot analysis to detect rearrangement of the mixed lineage leukemia (MLL) gene was performed when possible. The samples from 23 of 114 patients studied demonstrated anomalous expression of CD56 on myeloblasts, including patients with AML, myelodysplastic syndromes (MDS), and chronic myelogenous leukemia in blast crisis. The samples from 10 of 15 patients with CD56+ AML demonstrated at least partial monocytic differentiation. Dysplastic features were displayed in the samples of 12 patients. Correlation with specific cytogenetic abnormalities was not found. The MLL gene was rearranged in five of 18 patients. Seventeen patients have died, with a median survival of 4.6 months for patients with AML. Three have sustained a complete remission. One has findings of high-grade myelodysplastic syndrome. Two were unavailable for follow-up. Expression of CD56 was found in 20% of patients with increased myeloblasts, including patients with high-grade MDS, chronic myelogenous leukemia in blast crisis, and AML. This phenotype was associated with dysplasia, monocytic differentiation, and rearrangement of the MLL gene.

背景与目标： CD56抗原通常在自然杀伤细胞上表达，但另外已显示出存在于多种血液系统恶性肿瘤中，包括急性骨髓性白血病 (AML) 的一部分。然而，关于其预后意义及其与特定细胞遗传学异常的关联存在分歧。通过多参数流式细胞术分析了所有来自1995年9月的成髓细胞增加的1994年6月的临床样本中cd56的异常表达。选择CD56 + 原始细胞的患者，并进行形态学检查。获得临床信息，并回顾细胞遗传学数据。在可能的情况下，进行Southern印迹分析以检测混合谱系白血病 (MLL) 基因的重排。来自114例患者中的23例的样本显示出CD56在成髓细胞上的异常表达，包括患有AML，骨髓增生异常综合征 (MDS) 和处于爆炸危机中的慢性粒细胞性白血病的患者。来自15例CD56 AML患者中的10例的样本显示出至少部分单核细胞分化。在12例患者的样本中显示出发育异常的特征。未发现与特定细胞遗传学异常的相关性。18例患者中有5例重排了MLL基因。17名患者死亡，AML患者的中位生存期为4.6个月。三个已经完全缓解。有人发现了高度骨髓增生异常综合征。两个无法进行随访。在20% 的成髓细胞增加的患者中发现了CD56的表达，包括患有高级别MDS，处于爆炸危机中的慢性粒细胞性白血病和AML的患者。这种表型与发育异常，单核细胞分化和MLL基因的重排有关。

BACKGROUND & AIMS: :Immunohistochemical techniques were used to observe the localization of paraquat in the small intestine, liver and kidney, organs that absorb and eliminate chemicals. Paraquat-poisoned rats were killed 3 h, 12 h, 24 h, 3 days, 7 days and 10 days after intravenous administration of paraquat. Three hours after injection, paraquat was localized in hepatocytes and in the kidney in the epithelial cells of the distal tubule. The amount of paraquat in the liver and kidney increased by 24 h after the administration and thereafter decreased with time, suggesting that paraquat is secreted into bile and urine. In the intestine, 3 h after injection, paraquat was localized in the epithelial cells. The same finding was also made in rats with a cannulated bile duct. Therefore, it is likely that paraquat is secreted into the gut lumen from epithelial cells and that paraquat secreted from liver into the duodenum is reabsorbed into the epithelial cells of the intestine.

背景与目标： : 免疫组织化学技术用于观察百草枯在小肠，肝脏和肾脏，吸收和消除化学物质的器官中的定位。静脉注射百草枯后3 h，12 h，24 h，3天，7天和10天杀死百草枯中毒的大鼠。注射三小时后，百草枯位于肝细胞和远端小管上皮细胞的肾脏中。给药后24小时，肝脏和肾脏中的百草枯量增加，此后随时间减少，这表明百草枯分泌到胆汁和尿液中。在肠中，注射后3小时，百草枯位于上皮细胞中。在具有插管胆管的大鼠中也有相同的发现。因此，百草枯很可能从上皮细胞分泌到肠腔中，而百草枯从肝脏分泌到十二指肠被重新吸收到肠的上皮细胞中。

BACKGROUND & AIMS: Neurologic injury in infection with Borrelia burgdorferi can be due to the direct action of the spirochetes and spirochetal products on neural cells. There is in vitro evidence for the adherence of this organism to neurons, to glia, and to Schwann cells. Adhesion was found to be associated with galactocerebroside, a glycolipid component of myelin, and could act as a receptor for B. burgdorferi in oligodendroglia and in Schwann cells. Another pathway for neurologic injury could be through amplification of the inflammatory response by newly invading organisms (acute) and persisting (chronic) organisms. There is experimental evidence for production of IL-6, TNF-alpha, and nitric oxide by neural cells exposed to B. burgdorferi. Similar findings have been obtained from neuroborreliosis patients. Although less likely, there is the possibility that autoreactive mechanisms could have a role in the development of some manifestations of neuroborreliosis.

背景与目标： 伯氏疏螺旋体感染中的神经系统损伤可能是由于螺旋体和螺旋体产物对神经细胞的直接作用所致。有体外证据表明该生物粘附于神经元，神经胶质细胞和雪旺氏细胞。发现粘附与半乳糖脑苷 (一种髓磷脂的糖脂成分) 有关，并且可以作为少突胶质细胞和雪旺氏细胞中伯氏杆菌的受体。神经系统损伤的另一种途径可能是通过新入侵的生物体 (急性) 和持续存在的 (慢性) 生物体放大炎症反应。有实验证据表明暴露于伯氏杆菌的神经细胞产生IL-6，TNF-α 和一氧化氮。从神经疏螺旋症患者中也获得了类似的发现。尽管可能性较小，但自身反应性机制可能在神经疏螺旋症的某些表现的发展中发挥作用。

BACKGROUND & AIMS: OBJECTIVE:To identify reasons why rural general practitioners (GPs) treat a large proportion of patients with a primary psychiatric diagnosis in general beds of their local hospitals, and the barriers encountered when providing this treatment. DESIGN:A postal questionnaire was developed and distributed to a sample of rural GPs, asking about the treatment of patients with an acute mental illness in their local hospital. RESULTS:The majority of GPs agreed that they treat the acutely mentally ill in general beds of their local hospital due to lack of availability of, and inability to gain access to, mental health beds in the larger centres; and also to enable ongoing family involvement and continuity of care. Distance factors were identified as least significant. Barriers to providing care to this group of patients included a perceived lack of support by consultant psychiatrists, confidentiality issues, lack of community mental health workers to provide assistance, aggression levels of patients, inappropriate local hospital setting, and lack of confidence of GPs and general hospital nursing staff. CONCLUSION:Addressing these barriers is necessary if rural Australians are to receive a quality of care that is equal to that received by those located in metropolitan Australia. Continuing research in this area is crucial.

背景与目标：

BACKGROUND & AIMS: :Hypoxia changes the regional distribution of cerebral blood flow and stimulates the ventilatory chemoreflex, thereby reducing CO2 tension. We examined the effects of both hypoxia and isocapnic hypoxia on acute changes in internal carotid (ICA) and vertebral artery (VA) blood flow. Ten healthy male subjects underwent the following two randomly assigned respiratory interventions after a resting baseline period with room air: (i) hypoxia; and (ii) isocapnic hypoxia with a controlled gas mixture (12% O2; inspiratory mmHg). In the isocapnic hypoxia intervention, subjects were instructed to maintain the rate and depth of breathing to maintain the level of end-tidal partial pressure of CO2 ( ) during the resting baseline period. The ICA and VA blood flow (velocity × cross-sectional area) were measured using Doppler ultrasonography. The was decreased (-6.3 ± 0.9%, P < 0.001) during hypoxia by hyperventilation (minute ventilation +12.9 ± 2.2%, P < 0.001), while was unchanged during isocapnic hypoxia. The ICA blood flow was unchanged (P = 0.429), while VA blood flow increased (+10.3 ± 3.1%, P = 0.010) during hypoxia. In contrast, isocapnic hypoxia increased both ICA (+14.5 ± 1.4%, P < 0.001) and VA blood flows (+10.9 ± 2.4%, P < 0.001). Thus, hypoxic vasodilatation outweighed hypocapnic vasoconstriction in the VA, but not in the ICA. These findings suggest that acute hypoxia elicits an increase in posterior cerebral blood flow, possibly to maintain essential homeostatic functions of the brainstem.

背景与目标： : 缺氧改变脑血流的区域分布，刺激通气化学反射，从而降低CO2张力。我们检查了缺氧和异血管缺氧对颈内动脉 (ICA) 和椎动脉 (VA) 血流急性变化的影响。10名健康男性受试者在静息基线期后接受了以下两种随机分配的呼吸干预措施: (i) 缺氧; 和 (ii) 用受控气体混合物 (12% O2; 吸气mmHg) 进行等缺血缺氧。在等缺血缺氧干预中，指导受试者在静息基线期间维持呼吸速率和呼吸深度以维持CO2 () 的潮气末分压水平。使用多普勒超声检查测量ICA和VA血流 (速度 × 横截面积)。在过度通气 (分钟通气 + 12.9 ± 2.2%，P <0.001) 的缺氧期间降低 (-6.3 ± 0.9%，P <0.001)，而在等缺血缺氧期间保持不变。缺氧时ICA血流量不变 (P = 0.429)，VA血流量增加 (+ 10.3 ± 3.1%，P = 0.010)。相反，等缺血缺氧增加了ICA (14.5 ± 1.4%，P <0.001) 和VA血流 (10.9 ± 2.4%，P <0.001)。因此，在VA中，低氧的血管舒张作用超过了低碳酸的血管收缩，但在ICA中却没有。这些发现表明，急性缺氧会引起大脑后部血流量的增加，可能会维持脑干的基本稳态功能。