Acute cerebral infarction in monkeys: an experimental study using MR imaging

Magnetic resonance (MR) imaging was performed in five monkeys with experimentally induced acute cerebral infarction to define the MR imaging features and correlate these with computed tomographic (CT) findings, laboratory analysis, and histopathologic studies. Acute infarct (2-4 hours after embolization) was generally visible on MR images but not on CT scans. CT at 24 and 48 hours did show the infarcts. In all cases the infarct was more clearly depicted with MR imaging and was visualized as an area of high signal intensity on T2-weighted images. Spectrometric nuclear MR measurements of the postmortem cerebral tissue confirmed prolongation of both T1 and T2 values similar to that calculated from MR images. At postmortem laboratory testing, the area of infarction detected with MR imaging had decreased specific gravity and increased water content, reflecting edema.     

Maternal and infant outcomes at one year for a nurse-health advocate home visiting program serving African Americans and Mexican Americans

This article describes the outcomes at 1 year for a randomized clinical trial of Resources, Education and Care in the Home-Futures: a program to reduce infant mortality through home visits by a team of trained community residents led by a nurse. Low-income, inner-city pregnant women who self-identified as African American or Mexican American were recruited in two university prenatal clinics in Chicago. Because African Americans and Mexican Americans differed greatly at intake, we compared their outcomes at 12 months and then examined the effects of the intervention separately for these two groups. Participants were randomly assigned to the intervention or control group and were interviewed during the last trimester of pregnancy and at 2, 6, and 12 months after birth. The effects of the program varied by race/ethnicity. For African Americans, the program was associated with better maternal documentation of infant immunizations, more developmentally appropriate parenting expectations, and higher 12-month infant mental development scores. For Mexican Americans, the program had positive effects on maternal daily living skills and on the play materials subscale of the Home Observation for the Measurement of the Environment assessment. This study, along with previous research, suggests that home visits by a nurse-health advocate team can improve maternal and infant outcomes even for inner-city, low-income, minority families. Effective programs must be culturally sensitive, intensive, and adequately staffed and financed.     

Hemodilution and intravenous perflubron emulsion as an alternative to blood transfusion: effects on tissue oxygenation during profound hemodilution in anesthetized dogs

BACKGROUND: Intravenously administered perfluorocarbon (PFC) emulsions increase oxygen solubility in plasma. PFC might therefore temporarily replace red cells (RBCs) lost during intraoperative hemorrhage. In patients who have undergone hemodilution, the return of autologous blood may be delayed by the administration of PFC, and autologous RBCs may be saved for transfusion after surgical bleeding is stopped and PFC is cleared by the reticuloendothelial system. STUDY DESIGN AND METHODS: In 22 anesthetized, hemodiluted dogs (hemoglobin [Hb] 7 g/dL) breathing 100-percent O2, an intraoperative volume-compensated blood loss was simulated. The efficacy of three therapeutic regimens in maintaining tissue oxygenation was compared: 1) RBC group (n = 7): maintenance of a Hb > 7 g per dL by transfusion of autologous RBCs; 2) PFC group (n = 7): bolus application of a second-generation PFC emulsion (60% wt/vol perflubron) and further acute normovolemic hemodilution (ANH) to a Hb of 3 g per dL; and 3) control group (n = 7): further ANH alone to a Hb of 3 g per dL. Systemic and myocardial oxygenation status and tissue oxygenation were assessed. RESULTS: Autologous RBCs transfused to maintain a Hb of 7 g per dL preserved hemodynamics and tissue oxygenation during blood loss. In the PFC and control groups, heart rate and cardiac index increased significantly in response to further ANH. Tissue oxygenation was not different in the PFC and the RBC groups. Direct comparison of the PFC and control groups revealed better tissue oxygenation in the PFC group, as reflected by significantly higher mixed venous, coronary venous, and local tissue pO2 on liver and skeletal muscle. CONCLUSION: Bolus intravenous administration of 60- percent (wt/vol) perflubron emulsion and further hemodilution from a Hb of 7 g per dL to one of 3 g per dL were as effective as autologous RBC transfusion in maintaining tissue oxygenation during volume-compensated blood loss designed to mimic surgical bleeding.     

CenteringPregnancy-Africa: A pilot of group antenatal care to address Millennium Development Goals

Background

severe health worker shortages and resource limitations negatively affect quality of antenatal care (ANC) throughout sub-Saharan Africa. Group ANC, specifically CenteringPregnancy (CP), may offer an innovative approach to enable midwives to offer higher quality ANC.

Objective

our overarching goal was to prepare to conduct a clinical trial of CenteringPregnancy-Africa (CP-Africa) in Malawi and Tanzania. In Phase 1, our goal was to determine the acceptability of CP as a model for ANC in both countries. In Phase 2, our objective was to develop CP-Africa session content consistent with the Essential Elements of CP model and with national standards in both Malawi and Tanzania. In Phase 3, our objective was to pilot CP-Africa in Malawi to determine whether sessions could be conducted with fidelity to the Centering process.

Setting

Phases 1 and 2 took place in Malawi and Tanzania. Phase 3, the piloting of two sessions of CP-Africa, occurred at two sites in Malawi: a district hospital and a small clinic.

Design

we used an Action Research approach to promote partnerships among university researchers, the Centering Healthcare Institute, health care administrators, health professionals and women attending ANC to develop CP-Africa session content and pilot this model of group ANC.

Participants

for Phases 1 and 2, members of the Ministries of Health, health professionals and pregnant women in Malawi and Tanzania were introduced to and interviewed about CP. In Phase 2, we finalised CP-Africa content and trained 13 health professionals in the Centering Healthcare model. In Phase 3, we conducted a small pilot with 24 pregnant women (12 at each site).

Measurements and findings

participants enthusiastically embraced CP-Africa as an acceptable model of ANC health care delivery. The CP-Africa content met both CP and national standards. The pilot established that the CP model could be implemented with process fidelity to the 13 Essential Elements. Several implementation challenges and strategies to address these challenges were identified.

Key conclusions

preliminary data suggest that CP-Africa is feasible in resource-constrained, low-literacy, high-HIV settings in sub-Saharan Africa. By improving the quality of ANC delivery, midwives have an opportunity to make a contribution towards Millennium Development Goals (MDG) targeting improvements in child, maternal and HIV-related health outcomes (MDGs 4, 5 and 6). A clinical trial is needed to establish efficacy.

Implications for practice

CP-Africa also has the potential to reduce job-related stress and enhance job satisfaction for midwives in low income countries. If CP can be transferred with fidelity to process in sub-Saharan Africa and retain similar results to those reported in clinical trials, it has the potential to benefit pregnant women and their infants and could make a positive contribution to MGDs 4, 5 and 6.     

Effectiveness of 7-valent pneumococcal conjugate vaccine against radiologically diagnosed pneumonia in indigenous infants in Australia

Objective

To evaluate the effectiveness of the 7-valent pneumococcal conjugate vaccine (PCV7) in preventing pneumonia, diagnosed radiologically according to World Health Organization (WHO) criteria, among indigenous infants in the Northern Territory of Australia.

Methods

We conducted a historical cohort study of consecutive indigenous birth cohorts between 1 April 1998 and 28 February 2005. Children were followed up to 18 months of age. The PCV7 programme commenced on 1 June 2001. All chest X-rays taken within 3 days of any hospitalization were assessed. The primary endpoint was a first episode of WHO-defined pneumonia requiring hospitalization. Cox proportional hazards models were used to compare disease incidence.

Findings

There were 526 pneumonia events among 10 600 children – an incidence of 3.3 per 1000 child-months; 183 episodes (34.8%) occurred before 5 months of age and 247 (47.0%) by 7 months. Of the children studied, 27% had received 3 doses of vaccine by 7 months of age. Hazard ratios for endpoint pneumonia were 1.01 for 1 versus 0 doses; 1.03 for 2 versus 0 doses; and 0.84 for 3 versus 0 doses.

Conclusion

There was limited evidence that PCV7 reduced the incidence of radiologically confirmed pneumonia among Northern Territory indigenous infants, although there was a non-significant trend towards an effect after receipt of the third dose. These findings might be explained by lack of timely vaccination and/or occurrence of disease at an early age. Additionally, the relative contribution of vaccine-type pneumococcus to severe pneumonia in a setting where multiple other pathogens are prevalent may differ with respect to other settings where vaccine efficacy has been clearly established.     

诺卡式菌性角膜炎表现为盘状角膜炎1例

目的:报告诺卡式菌属感染引起的盘状角膜炎病例1例。方法:病例报告。结果:患者,男,13岁,无角膜接触镜使用史,在小溪里游泳后,右眼疼痛伴视力下降2wk。最佳矫正视力:右眼6/30(0.2)。检查发现角膜基质存在形态规则的旁中心盘状浸润伴炎症反应。角膜敏感度下降。最初角膜刮片镜检行革兰氏染色阴性,棘阿米巴角膜刮片和培养阴性。诊断为病毒性盘状角膜炎,给予口服阿昔洛韦和局部使用激素眼药水。2wk后患者视力恶化伴角膜损伤加重,再次角膜取材刮片行革兰氏染色提示诺卡式菌属感染,按经验局部给予3g/L加替沙星眼药水后,临床效果明显。治疗6mo后,视力达到6/6仅在角膜中心留有少量角膜混浊。结论:诺卡式菌属感染延误诊断可以导致病情恶化。如果采用正确的治疗,诺卡式菌属感染引起的角膜炎可以恢复良好,仅留少量瘢痕,获得较好的视力。     

Hematopoietic cell activation in the subventricular zone after Theiler's virus infection

Background

The long latent stage seen in syphilis, followed by chronic central nervous system infection and inflammation, can be explained by the persistence of atypical cystic and granular forms of Treponema pallidum. We investigated whether a similar situation may occur in Lyme neuroborreliosis.

Method

Atypical forms of Borrelia burgdorferi spirochetes were induced exposing cultures of Borrelia burgdorferi (strains B31 and ADB1) to such unfavorable conditions as osmotic and heat shock, and exposure to the binding agents Thioflavin S and Congo red. We also analyzed whether these forms may be induced in vitro, following infection of primary chicken and rat neurons, as well as rat and human astrocytes. We further analyzed whether atypical forms similar to those induced in vitro may also occur in vivo, in brains of three patients with Lyme neuroborreliosis. We used immunohistochemical methods to detect evidence of neuroinflammation in the form of reactive microglia and astrocytes.

Results

Under these conditions we observed atypical cystic, rolled and granular forms of these spirochetes. We characterized these abnormal forms by histochemical, immunohistochemical, dark field and atomic force microscopy (AFM) methods. The atypical and cystic forms found in the brains of three patients with neuropathologically confirmed Lyme neuroborreliosis were identical to those induced in vitro. We also observed nuclear fragmentation of the infected astrocytes using the TUNEL method. Abundant HLA-DR positive microglia and GFAP positive reactive astrocytes were present in the cerebral cortex.

Conclusion

The results indicate that atypical extra- and intracellular pleomorphic and cystic forms of Borrelia burgdorferi and local neuroinflammation occur in the brain in chronic Lyme neuroborreliosis. The persistence of these more resistant spirochete forms, and their intracellular location in neurons and glial cells, may explain the long latent stage and persistence of Borrelia infection. The results also suggest that Borrelia burgdorferi may induce cellular dysfunction and apoptosis. The detection and recognition of atypical, cystic and granular forms in infected tissues is essential for the diagnosis and the treatment as they can occur in the absence of the typical spiral Borrelia form.