Cerebral microembolism in patients with retinal ischemia

BACKGROUND AND PURPOSE: We investigated the frequency of cerebral microembolism detected by transcranial Doppler ultrasonography in patients with clinical evidence of retinal ischemia, including transient monocular blindness, central and branch retinal artery infarction, and ischemic oculopathy, and assessed its correlation with carotid artery stenosis. METHODS: Records of 331 consecutive patients examined during a 47-month period at the Neurovascular Laboratory were reviewed. Of the original 453 intracranial arteries, 186 middle cerebral arteries (MCAs) satisfied qualifying criteria that excluded patients with cardiac embolic sources. Forty-five MCAs ipsilateral to the symptomatic eye constituted the study group. The control group consisted of 141 asymptomatic MCAs. Microembolus detection studies were performed on transcranial Doppler instruments equipped with special software, and the degree of carotid artery stenosis was measured by cerebral or MR angiography or by color duplex studies. RESULTS: Microembolism was detected in 40.0% of study MCAs and 9.2% of controls (P < 0.001). In the study group, microembolic signals were detected in 61.9% of MCAs tested within a week of symptom onset and 20.8% of those tested afterward (P < 0.001). Severe (> or = 70%) carotid stenosis or occlusion was more frequent in the study group (P < 0.001). Microembolic signals were detected in 25.3% and 11.2%, respectively, of MCAs distal to carotid arteries with 70% to 100% and 0% to 69% stenosis (P = 0.013). CONCLUSIONS: In patients without cardiac embolic sources, cerebral microembolism is frequently present on the side of retinal ischemia, particularly during the week after onset of symptoms. It is often associated with severe stenosis or occlusion of the ipsilateral carotid artery.     

Leadership and communication in nursing management

Considering communication and leadership, authors examine the role of the leader as a focus of reception and transmission of information, based on the classification of Mintzberg related to their informative roles, such as the leader acting as monitor, disseminator and spokesman. Contextualizing this approach in the scenery of nursing management, authors study the dimension of nurses-leaders role as an essential element of communication in the systems of organization of nursing care.     

The response of gamma delta T cells to Plasmodium falciparum is dependent on activated CD4+ T cells and the recognition of MHC class I molecules

Peripheral blood gamma delta T cells from non-exposed individuals respond to antigens of the malaria parasite, Plasmodium falciparum, in vitro. This response, largely caused by T cells bearing the V gamma 9+ chain of the T-cell receptor, is stimulated by components of the parasite expressed on the schizont stage and released at schizont rupture. The response of V gamma 9+ T cells to parasite components is inhibited by antibodies to major histocompatibility complex (MHC) class I and class II. However, the inhibition by anti-MHC class II antibodies can be overcome by the addition of interleukin-2 (IL-2) to the cultures, suggesting that gamma delta T cells themselves do not recognize MHC class II molecules but require an MHC class II-dependent response taking place in the culture. In contrast, the inhibition by anti-class I antibodies cannot be reversed by addition of IL-2. Since an accompanying CD4+ T-cell response occurred in peripheral blood mononuclear cells cultured with P falciparum antigens, it was considered that these cells provide the cytokines necessary for the subsequent activation and expansion of V gamma 9+ T cells recognizing components of the parasite and MHC class I molecules. This was confirmed by reconstituting the response of enriched gamma delta T cells to P falciparum schizont extract by addition of purified CD4+ T cells.     

Effects of aging, diet, and sex on plasma glucose, fructosamine, and lipid concentrations in barrier-raised Fischer 344 rats

We studied the relationships of plasma glucose, fructosamine, triglycerides, and cholesterol as a function of age, gender, and diet in barrier-raised Fischer 344 rats aged 5 to 26 months, fed a diet either ad libitum or restricted to 60% of the ad libitum caloric intake. The complex relationships of these plasma levels to age, gender, and diet led to the development of a model with age, diet, and sex as covariates. Overall, fasting plasma glucose concentrations were reduced by approximately 25% in rats on the restricted diet, compared to ad libitum-fed animals. There was a significant age-dependent decline in glucose levels in male animals, whereas in females there was an increase in plasma glucose with aging. Plasma fructosamine levels in calorie-restricted animals, overall, were reduced by 7% compared to levels in animals fed ad libitum. There was a significant positive correlation between plasma glucose and fructosamine levels. Mean plasma triglyceride content was decreased by 50% in calorie-restricted rats compared to ad libitum-fed animals. A significant decrease in triglyceride levels with increasing age was seen in male animals, and an increase with aging in females. There was a significant positive correlation between plasma glucose and triglyceride levels. Plasma cholesterol levels in calorie-restricted animals were reduced by 7% compared to levels in ad libitum-fed animals. An increase of cholesterol concentration with aging was significant in both males and females. Analysis of the data showed that there were significant differences between male and female Fischer 344 rats in the response of plasma glucose and fructosamine to aging and calorie restriction. Changes of plasma triglyceride and cholesterol with aging and dietary calorie restriction were also different in males and females. Studies of the effect of aging on glycemia and blood lipid content should take into account the contributions of animal sex.     

Pulmonary thrombo-endarterectomy]

Chronic pulmonary thromboembolism is an underdiagnosed condition with major morbidity and mortality. Over the past year and a half, we diagnosed 6 new cases of which 3 underwent successful, pulmonary thrombo-endarterectomy (2 in San Diego, 1 in Jerusalem). All recovered fully and returned to normal, active life. We conclude that pulmonary thrombo-endarterectomy is a viable option for patients with chronic pulmonary thromboembolism.     

Clinical documentation of end-stage renal disease due to hypertension

Hypertensive end-stage renal disease (ESRD) purportedly accounts for 25% of new ESRD patients each year in the United States, but remains poorly understood. Clinical features include normal renal function at diagnosis of hypertension, family history of hypertension, left ventricular hypertrophy, and minimal proteinuria. We evaluated clinical and historic data documenting the diagnosis of hypertensive ESRD in 43 patients with ESRD attributed to hypertension who were referred to our center for renal transplantation. Hypertensive ESRD patients were more likely to be black patients with left ventricular hypertrophy compared with our overall population. Few of the hypertensive ESRD patients had undergone kidney biopsy, none of whom had classic features of benign nephrosclerosis. Less than 5% of patients had hypertension documented at any time with normal renal function. Based on our review, it is clearly possible that the number of patients reaching dialysis and transplantation with renal failure attributed to hypertensive ESRD may be overestimated.     

Primary binding domain of bovine von Willebrand factor fragment expressed in E. coli

Bovine vWF cDNA has been cloned from a bovine endothelial cell library. A fragment of this cDNA, corresponding to amino acid sequence Leu 469-Ser 723, called primary adhesion domain (PAD-1), and containing the binding sites for platelet glycoprotein Ib (GPIb), heparin and collagen, has been expressed in E. coli. The reduced and alkylated form of fragment PAD-1 inhibited native vWF binding to GPIb. Fragment PAD-1 bound to heparin and botrocetin in a specific and dose dependent manner as did the native vWF. In a solid-phase assay, fragment PAD-1 bound to calf skin collagen in contrast to a human vWF recombinant fragment (Ser 445-Val 733) which was inactive in the same assay. The studies presented in this paper demonstrated that the A1 domain of bovine vWF contained the GPIb, heparin, botrocetin as well as collagen binding sites and that integrity of the disulfide bond (Cys 509-Cys 695), did not seem to be essential for binding of bovine vWF fragment to GPIb.