Astigmatism management: ablation patterns

Treatment of astigmatism is possible with the excimer laser. Results with this technology are more predictable and accurate than with incisional techniques. Ablation profiles differ for the various types of astigmatism, and the best approach is the one in which the least amount of tissue is removed from the cornea. Surgical success requires appropriate preoperative counseling, careful preoperative measurements, and meticulous intraoperative technique. Reported outcomes are excellent and future developments will lead to even better results.     

The relationship between GABA-containing cells and the cholinergic circuitry in the rabbit retina

As a part of ongoing efforts to understand the cholinergic circuitry in the mammalian retina, we studied the coexpression of nicotinic acetylcholine receptors (nAChRs) and gamma-aminobutyric acid (GABA), the GABA transporter 1 (GAT-1), or choline acetyltransferase (ChAT) immunoreactivity in the rabbit retina. Double-label experiments with monoclonal antibody 210 (mAb 210) against nAChRs and antibodies against GABA revealed that several populations of GABA-containing amacrine, displaced amacrine, and ganglion cells displayed nAChR immunoreactivity. Some of them also exhibited ChAT immunoreactivity and were identified as the cholinoceptive starburst cells. Other GABAergic amacrine cells positive for mAb 210 were not cholinergic. Simultaneous visualization of mAb 210 and GAT-1 immunoreactivity revealed that 10% of GAT-1 immunoreactive amacrine cells contained nAChRs. Ninety-nine percent of the GAT-1 labeled cells demonstrated GABA immunoreactivity, but only 75% of the GABAergic cells were outlined by GAT-1 staining. Neither population of starburst cells exhibited GAT-1 immunoreactivity. Thus, mAb 210 expressing, GAT-1 positive cells in the rabbit retina constitute a noncholinergic subset of GABAergic amacrine cells. Taken together, our results suggest that some GABAergic amacrine cells are cholinoceptive, raising the possibility that ACh, acting through nAChRs, can modulate the release of GABA in the rabbit retina.     

The coastal environment and human health: microbial indicators,pathogens, sentinels and reservoirs

Innovative research relating oceans and human health is advancing our understanding of disease-causing organisms in coastal ecosystems. Novel techniques are elucidating the loading, transport and fate of pathogens in coastal ecosystems, and identifying sources of contamination. This research is facilitating improved risk assessments for seafood consumers and those who use the oceans for recreation. A number of challenges still remain and define future directions of research and public policy. Sample processing and molecular detection techniques need to be advanced to allow rapid and specific identification of microbes of public health concern from complex environmental samples. Water quality standards need to be updated to more accurately reflect health risks and to provide managers with improved tools for decision-making. Greater discrimination of virulent versus harmless microbes is needed to identify environmental reservoirs of pathogens and factors leading to human infections. Investigations must include examination of microbial community dynamics that may be important from a human health perspective. Further research is needed to evaluate the ecology of non-enteric water-transmitted diseases. Sentinels should also be established and monitored, providing early warning of dangers to ecosystem health. Taken together, this effort will provide more reliable information about public health risks associated with beaches and seafood consumption, and how human activities can affect their exposure to disease-causing organisms from the oceans.     

Distinct clinical and laboratory activity of two recombinant interleukin-2 preparations.

Interleukin-2 (IL-2) is a potent lymphokine that activates natural killer cells, T cells, and other cells of the immune system. Several distinct recombinant human IL-2 preparations have shown antitumor activity, particularly for renal cell cancer and melanoma. Somewhat distinct immune and clinical effects have been noted when different IL-2 preparations have been tested clinically; however, the regimens and doses used were not identical. To compare these more directly, we have evaluated two clinical recombinant IL-2 preparations in vitro and in vivo using similar regimens and similar IUs of IL-2. We used the Food and Drug Administration-approved, commercially available Chiron IL-2 and the Hoffmann LaRoche (HLR) IL-2 supplied by the National Cancer Institute. Using equivalent IUs of IL-2, we noted quantitative differences in vitro and in vivo in the IL-2 activity of these two preparations. In patients receiving comparable IUs of the two preparations, HLR IL-2 induced the release of more soluble IL-2 receptor alpha into the serum than Chiron IL-2. In addition, more toxicities were noted in patients receiving 1.5 x 10(6) IU of HLR IL-2 than were seen in patients treated with 1.5 x 10(6) or even 4.5 x 10(6) IU of Chiron IL-2. These toxicities included fever, nausea and vomiting, and hepatic toxicity. In vitro proliferative assays using IL-2-dependent human and murine cell lines indicated that the IU of HLR IL-2 was more effective than Chiron IL-2 at inducing tritiated thymidine incorporation. Using flow cytometry, we also found quantitative differences in the ability of these two preparations to bind to IL-2 receptors. These findings indicate that approximately 3-6 IU of Chiron IL-2 are required to induce the same biological effect as 1 IU of HLR IL-2.     

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.     

磁共振胰胆管造影在阻塞性黄疸诊断中的应用

目的　评价磁共振胰胆管造影 (MRCP)技术在阻塞性黄疸诊断中的临床应用价值。方法　采用GE超导0 .5T ,Vectra 2磁共振成像仪 ,快速自旋回波 (FSE)重T2 加权扫描及最大强度投影 (MIP)重建图像 ,对 48例阻塞性黄疸患者作MRCP检查 ,所有患者均经手术证实。结果　各种病变的MRCP图像均有其特征性表达 ,MRCP对阻塞性黄疸的定位准确率为 10 0 % ,定性准确率为 93 .8%。结论　MRCP对阻塞性黄疸的诊断是一种有效、安全、可靠的方法。