尼群的平对麻醉犬冠脉流量、心肌耗氧量、二氧化碳产生率的影响

尼群的平20μg/kg iv显著降低麻醉犬血压的过程,冠状窦流量明显增加。持续3h,冠状窦氧含量增加,氧摄取率、心肌耗氧量、二氧化碳产生率降低,持续了3h以上,说明该剂适用于高血压伴心肌缺血。     

Regional block and DVT prophylaxis

The last few years have seen increasing concerns among anaesthetistsabout the risks of pharmacological prophylaxis for thromboembolicdisease. Increased bleeding during or after surgery is one concern,but of greater significance is the possibility of an increasedpredisposition to haematoma formation when regional block isused. Most of the recent consideration of this problem has beenin relation to vertebral canal haematoma formation after centralnerve block. Some thought must be given also to the possibilityof haematoma formation after peripheral techniques when thetarget nerve is deeply placed so that pressure cannot be usedto control bleeding after needle insertion. However, this reviewwill be focused on vertebral canal haematoma.     

Neuroblastoma-derived gangliosides inhibit dendritic cell generation and function

Neuroblastoma (NB), a tumor of the sympathetic nervous system, is the most common extracranial solid tumor in children. NB-derived gangliosides inhibit the functional activity of T and natural killer cells, contribute to tumor-induced bone marrow suppression, and cause multiple alterations of hematopoiesis, resulting in pancytopenia. However, the role of gangliosides in the regulation of dendritic cell (DC) generation (dendropoiesis) has not been studied. Using murine and human NB cell lines, we demonstrated that coincubation of murine bone marrow progenitors or human CD34+ progenitor cells with NB cells resulted in a significant inhibition of dendropoiesis in vitro up to 90%. The number of DCs was assessed by FACScan determination of CD83+ or CD11c+ cells coexpressing MHC class II and CD86 molecules. In addition, inhibition of antigen-presenting properties of DCs cultured in the presence of NB cells was observed in allogeneic mixed leukocyte reaction (33,508 +/- 1,613 cpm for control DCs versus 17,428 +/- 152 cpm for NB-treated DCs; P < 0.05). Treatment of NB cells with 10 microM DL-threo-1-phenyl-2-decanolylamine-3-morpholino-1-propanol HCl, an inhibitor of glucosylceramide synthase, markedly abrogated ganglioside synthesis and was accompanied by blockade of NB ability to inhibit dendropoiesis. Furthermore, purified gangliosides added to DC cultures significantly inhibited DC generation. The percentage of CD83+ cells decreased from 51.8 +/- 6.1% in the control group to 12.9 +/- 2.7% in cultures treated with GD2 (P < 0.05). Thus, our results demonstrate that NB-derived gangliosides inhibit the generation of functionally active DCs and may play a role in tumor-induced immunosuppression and subsequent tumor escape from immune recognition and elimination.     

Prevalence of risk factors for cardiovascular disease in Canadians 55 to 74 years of age: results from the Canadian Heart Health Surveys, 1986-1992

BACKGROUND: By 2016, the proportion of Canadians older than 65 years of age will increase to 16%, and there will be an increase in the absolute number of cases of cardiovascular disease in older Canadians. The Canadian Heart Health Surveys database provides information about this population upon which health policy related to cardiovascular disease can be based. This paper presents for the first time population-based data on the risk factors for cardiovascular disease in older Canadians. METHODS: Canadians from all 10 provinces participated in surveys of cardiovascular risk factors; health insurance registries were used as sampling frames. In each province, probability samples of 2200 adults 18 to 74 years old not living in institutions, on reserves or in military camps were asked to participate in interviews and to undergo testing at clinics for major risk factors for cardiovascular disease. RESULTS: A total of 2739 men (response rate 70%) and 2617 women (response rate 66%) aged 55 to 74 years participated in the survey and also provided follow-up clinical measurements at the clinic. Overall, 52% of participants were hypertensive, 26% had isolated systolic hypertension, and 30% had a total blood cholesterol level of 6.2 mmol/L or greater. Rates of current smoking were lower in women than men (17% v. 22%). Overall, 87% of men and 78% of women who were current smokers smoked at least 10 cigarettes per day. Only slightly more than half of participants exercised at least once a week for at least 15 minutes, and almost half had a body mass index of 27 or greater. In only 4% was no major risk factor for cardiovascular disease detected. INTERPRETATION: Significant numbers of older Canadians have one or more major risk factors for cardiovascular disease. Many of these risk factors are amenable to modification.     

The role of recombination signal sequences in the preferential joining by deletion in DH-JH recombination and in the ordered rearrangement of the IgH locus

The bias favoring deletion over inversion in DH-JH rearrangement has been known for years, but the underlying mechanism has yet to be fully defined. It has been suggested that the ratio of deletion/inversion is determined by the combined effect of two factors: (i) the relative strengths of 5' and 3' recombination signal sequences (RSS) of a DH segment, and (ii) the efficiency with which the deletional product (one joint) forms relative to the inversional product (two joints). In this study, we analyzed for the first time the effect of factor 1 alone on the biased 3' RSS utilization in DH-JH joining by using deletional plasmids in an extrachromosomal substrate V(D)J recombination assay. It was found that the 3' RSS and associated coding end (12 bp) mediate recombination more efficiently than the 5' RSS/coding end DH-JH plasmids. These results demonstrate that the effect of the RSS/coding end alone can account, at least partially, for the predominant deletion in DH-JH recombination. The potential effect of the relative strength of RSS and associated coding end on the ordered rearrangement of DH-JH followed by VH to DH-JH was also assessed. When recombination frequencies of D-->J (3' DH to J3) were compared with frequencies of V-- >D (VHPJ14 to 3' DH or VHOX2 to 3' DH), it was found that V-->D joining was, if anything, more efficient than D-->J joining. Therefore, if all three segments were accessible, RSS/coding end effects would not contribute to the ordered rearrangement of the IgH locus.      

Precise intraoperative location of gastrointestinal bleeding with a hand-held counter. Work in progress

The nuclear medicine bleeding scan is frequently insufficient to locate sites of bleeding precisely, in spite of its great sensitivity. A small, hand-held Geiger-Müller counter, placed directly on exposed intestine in the operating room, enables precise location of the probable bleeding site. In three patients, the technique allowed a minimal amount of intestine to be resected, distinguished between large- and small-intestinal hemorrhage, and eliminated other foci as sites of bleeding.