Stability of insulin lispro in insulin infusion systems.

Objective: To test stability of insulin lispro in two insulin infusion systems over 48 h.

Research Design And Methods: We used reverse-phase and size-exclusion high-performance liquid chromatography (HPLC) to determine the purity, potency, and degree of polymerization of U100 insulin lispro (Humalog) after 24- and 48-h pump cycles conducted at 37 degrees C in five Disetronic H-TRON V100 and five MiniMed 504 pumps. Pumps were set to deliver a basal rate of 0.

Carotid microendarterectomy.

The illumination and magnification provided by the operating microscope allow for the accurate and complete removal of atherosclerotic plaque from the carotid arterial wall, for precise arterial repair at the distal end of the internal carotid endarterectomy, and for a fine, nonstenosing arteriotomy closure. A high dissection of the internal carotid artery, allowing arterial exposure above the plaque, is particularly helpful in the performance of carotid microendarterectomy. The technique of carotid microendarterectomy has been used in a consecutive series of 60 patients with symptomatic carotid stenosis, all but 5 of whom had carotid stenoses of 70% or more.

Gauze-induced granuloma ("gauzoma"): an uncommon complication of gauze reinforcement of berry aneurysms.

Incompletely and even adequately clipped berry aneurysms are often reinforced with finely shredded gauze. In seven female patients this practice led to a series of events including headache, pyrexia, seizures, cranial nerve deficits, endocrinopathy, cerebrospinal fluid pleocytosis, and an enhancing mass demonstrated by computerized tomography at the aneurysm site. One patient with blindness, hydrocephalus, and panhypopituitarism died and was examined at autopsy.

In vivo bicarbonate deficiency and insulin dissolution.

Exogenous insulin exists primarily as the monomer in human plasma. However, in U100 regular insulin formulations, the concentrations of zinc and peptide are such that the insulin hexamer predominates. The biologic result is further disassociation to the monomer after subcutaneous or i.

A technique for rapid non-suture vascular anastomosis.

In an attempt to overcome some of the difficulties inherent in vascular anastomosis using standard suture methods, we have developed a technique that allows for rapid non-suture anastomosis of blood vessels. The technique has been used in over 400 anastomoses, including interposition vein grafts in rat, rabbit and dog vessels ranging in size from 0.7 mm to 3 mm in diameter.

Stabilizing blood glucose with a novel medical expert system.

In health, metabolism is elegantly coordinated. Failure of an underlying process (as occurs in diabetes) disrupts the coordination and impacts on the global status of the affected individual. It takes a medical expert to intervene and restore order.

Monitoring of sensory evoked potentials during surgery of skull base tumours.

Despite advances in instrumentation and the use of microsurgical techniques, neurosurgical procedures involving extensive areas of skull base or other critical areas of brain still carry significant risk for neurological injury. The use of intraoperative recording of sensory evoked potentials (SEP) has been advocated to monitor neurologic function during these major neurosurgical procedures to reduce the risk of injury to neural structures. This report summarizes our experience with intraoperative monitoring of SEP in over 200 patients, and details our findings in a group of 12 patients with skull base and posterior fossa tumours.

Effect of perioperative platelet inhibition on postcarotid endarterectomy mural thrombus formation. Results of a prospective randomized controlled trial using aspirin and dipyridamole in humans.

A prospective randomized double-blind trial was conducted to study the effect of platelet-inhibiting drugs on mural thrombus formation after carotid endarterectomy. Twenty-two patients undergoing carotid endarterectomy were randomly assigned to perioperative administration of an aspirin/dipyridamole combination or a placebo, and the postoperative results were compared. Autologous indium-111-labeled platelets were injected postoperatively, and platelet deposition was measured at the endarterectomy site.

Physical stability of insulin formulations.

Insulin aggregation remains a fundamental obstacle to the long-term application of many insulin infusion systems. We here report the effects of physiologic and nonphysiologic compounds on the aggregation behavior of crystalline zinc insulin (CZI) solutions. Under conditions chosen to simulate the most severe that would be encountered in delivery systems (presence of air, continuous motion, and elevated temperature), both highly purified and regular CZI at 5 U/ml formed turbid gels in 5 days.

A physiological solvent for crystalline insulin.

Insulin is insoluble in water at physiological pH, but dissolves relatively rapidly in plasma. To quantify the ability of various solutions to dissolve crystalline insulin, a simple assay measuring dissolution time was developed. At pH 7.

For insulin infusion: a miniature precision peristaltic pump and silicone rubber reservoir.

This paper describes a miniature precision peristaltic pump and a silicone rubber reservoir developed for the infusion of insulin in diabetic subjects. The ability of the 100-ml reservoir to maintain sterility of its contents over 26 refilling cycles (48 days) is demonstrated. Accelerated bench tests on 10 pumps over 30 days indicate an accuracy of +/- 1% on flow rate whether measured over 10 min or 24 h and with or without 1 atm of outlet back pressure.

Nonaggregating insulin solutions for long-term glucose control in experimental and human diabetes.

A physiologic additive for dissolving insulin crystals for parenteral application has been found. Insulin crystals are relatively insoluble in simple aqueous solutions. They will dissolve, however, in highly acidic solutions, but these are not suitable for parenteral use.

Insulin delivery and the artificial beta cell: luminal obstructions in capillary conduits.

Insulin delivery mechanisms in which the polypeptide is conducted through the fine bore tubes develope luminal occlusions after 2-6 weeks. Scanning electron micrographs of the ends of such capillaries reveal that the usual methods of sectioning these tubes produces barbed and distorted exits on which aggregates of insulin appear to be localized. This paper addresses a novel technique for sectioning teflon (PTFE) capillary bore tubing which avoids this problem.

Thromboendarterectomy for total occlusion of the internal carotid artery: a reappraisal of risks, success rate and potential benefits.

Forty consecutive patients undergoing thromboendarterectomy for total internal carotid artery occlusion were studied in an attempt to determine a) whether careful case selection could be expected to reduce future postoperative mortality and morbidity, b) whether the achieved patency rate justified early operation and c) whether patients in whom patency was restored and maintained had a better long-term prognosis. The results show that a group of patients can be selected that will have low postoperative mortality and morbidity. The success rate for restoration of blood flow is high, particularly if the operation is performed soon after occlusion.