The kallikrein-kinin system in diabetic retinopathy: lessons for the kidney.

Diabetic retinopathy and diabetic nephropathy are common microvascular complications of diabetes. The kallikrein-kinin system (KKS) has been implicated in the development of both conditions, and, in particular, bradykinin and its receptors have been shown to exert angiogenic and proinflammatory actions. Several of the key processes that underlie the development of diabetic retinopathy, such as increased vascular permeability, edema, neovascularization, and inflammatory changes, have been associated with the KKS, and recent work has shown that components of the KKS, including plasma kallikrein, factor XIIa, and high-molecular-weight kininogen, are present in the vitreous of people with diabetic retinopathy. The role of the KKS in the development of diabetic nephropathy is controversial, with both adverse and protective effects of bradykinin and its receptors reported. The review examines the role of the KKS in pathways central to the development of diabetic retinopathy and compares this with reported actions of this system in diabetic nephropathy. The possibility of therapeutic intervention targeting bradykinin and its receptors as treatment for diabetic microvascular conditions is considered.

Temporal sensitivity deficits in patients with high-risk drusen.

PURPOSE: Data is reported from an ongoing trial considering functional losses in patients with high-risk drusen. We evaluate the temporal processing in 12 subjects: four patients with high-risk drusen, four age-matched controls and four young observers aged 22-30. METHODS: Subjects were tested using frequency-doubling technology, macula static and flicker fields on a Medmont perimeter and foveal temporal contrast sensitivity at 2, 5, 10 and 24 Hz. RESULTS: Eyes with high-risk drusen had good visual acuity (6/9.5(-2) or better). All control eyes had normal fields for static, flicker and frequency-doubling perimetry. All high-risk drusen eyes had normal static perimetry in the presence of abnormal flicker and frequency-doubling perimetry. High-risk drusen eyes showed a generalized loss of temporal sensitivity across all frequencies. CONCLUSIONS: We conclude that eyes with high-risk drusen show losses to temporal stimuli in the presence of near-normal acuity and static thresholds. We suggest that flickering stimuli might be useful for detecting and monitoring such patients.

Electrocardiographical changes in the peri-operative period. A pilot study.

The value of continuous electrocardiogram recording in the peri-operative period has been examined. In a group of 15 patients, 14 developed changes two of which persisted into the postoperative period. Dysrhythmias, ST segment and T-wave changes occurred frequently. Continuous recording is of potential benefit in the study of cardiovascular disease and therapy in the peri-operative period.

Measurement of plasma fentanyl concentration: comparison of three methods.

The measurement of plasma fentanyl concentration by radioimmunoassay (RIA) and gas liquid chromatography (GLC) using either a flame ionization detector (FID) or nitrogen/phosphorus detector (NPD) has been compared. RIA is a satisfactory but expensive method of measuring plasma fentanyl concentration. GLC using an FID is not as satisfactory as RIA, but when an NPD is used the results are equal to those of RIA. In addition, other analgesics which are chemically similar to fentanyl, such as alfentanil, may also be measured by the GLC/NPD combination using the same set of operating conditions. By contrast, an RIA method is usually specific for only one compound, and measurement of additional drugs would almost certainly necessitate the development of new assay kits for each one.

Amphetamines in the treatment of Parkinson's disease.

Twenty-two patients with Parkinsonism were treated with levoamphetamine and 12 of these with dextroamphetamine. Levoamphetamine resulted in a significant improvement in disability from Parkinsonism, although the reduction in total disability, tremor, akinesia, and rigidity scores was slight (ca 20 percent). Dextroamphetamine in lower dosage also reduced disability by some 17 percent. The most disabled patients, including those also on levodopa, showed the greatest response to amphetamines. Previously, amphetamines have been reported to be a selective treatment for the oculogyric crises of post-encephalitic Parkinsonism. Amphetamines are thought to cause the release of catecholamines from central neurones. Their action in Parkinson's disease may be limited because of pre-existing striatal dopamine deficiency. Side-effects of amphetamines, anorexia, and CNS stimulation are different from those caused by levodopa in patients with Parkinson's disease.