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Initial experience with a new flexible and adjustable mitral annuloplasty ring is described. Used in conjunction with standard techniques of mitral valve repair, this ring was implanted in 21 consecutive patients undergoing elective operation for mitral regurgitation. Satisfactory valve repair was feasible in 20 of these patients. Once the ring was sewn in place, adjustment of the ring to reduce or eliminate residual regurgitation was beneficial in 9 patients. Excellent results were achieved as determined by intraoperative transesophageal echocardiography. Comparable late results were found in all but 1 patient up to 1 year after repair. This patient required mitral valve replacement 6 months after repair due to failure of papillary muscle reconstruction. The BiFlex ring has the merits of a flexible prosthesis with the advantage of easy adjustment once secured in place.

To assess the outcome of emergency coronary artery bypass grafting (CABG) after failed percutaneous transluminal coronary angioplasty (PTCA), 91 patients undergoing emergency CABG after failed PTCA over a 30-month period ending July 31, 1991, were studied. For reference, a cohort of patients (91) concurrently undergoing elective CABG equally matched for age, sex, number of grafts, ventricular function, and reoperative status was compared. Specific outcomes including death, hospital length of stay, use of blood products, and development of myocardial infarction were analyzed. More than half the patients undergoing emergency CABG for failed PTCA required three or more grafts. Operative mortality was 12.1% (11/99) for emergency CABG compared with 1% (1/91) for elective case-matched CABG patients (p = 0.007). Emergency CABG patients required frequent use of postoperative inotropes (p = 0.02) and intraaortic balloon counterpulsation (p = 0.001). Length of hospital stay (p = 0.005), administration of blood products (p = 0.009), postoperative myocardial infarction (p = 0.0005), and ventricular arrhythmias (p = 0.0004) were increased after emergency compared with elective CABG. The presence of multivessel disease or use of a reperfusion catheter had no influence on clinical outcome. Despite accumulated experience and improved operative management, patients requiring emergency CABG for failed PTCA remain at increased risk for postoperative complications and death.

The signal-dependent sampling process in an acoustic charge transport (ACT) device is demonstrated. Theoretical calculations and experimental measurements show the direct effect of gate voltage, wave amplitude, and transport depth on the sampling interval. A decrease in gate voltage and transport depth, and an increase in wave amplitude, are shown to reduce the increase in sampling time delay for a fixed transport current. An analysis of the distortion generated by this nonuniform sampling is performed, and a channel-current-intercept value is computed for a typical ACT device.

Equipping ureteral instruments with the guide-eye feature has expanded the instrumentation options available to urologists. The guide-eye facilitates repetitive instrument access, allows coordinated instrument combinations, and enhances sequential placement of a series of instruments. We believe this concept increases the safety and efficacy of our present instruments and clearly encourages innovative designs for the future.

The metabolism of [1-14C]arachidonic acid [( 1-14C]AA) by washed platelets from macaques and human subjects was investigated. The results were as follows: At substrate levels of 1 microM, similar amounts of prostaglandin E2 (PGE2), prostaglandin F2 alpha (PGF2 alpha), prostaglandin D2 (PGD2), and thromboxane A2 (TXA2), measured as thromboxane B2 (TXB2), were produced from [1-14C]AA by platelets from rhesus, Celebes black, and cynomolgus macaques and humans. An increase in the AA concentration from 1 microM to 20 microM decreased the TXB2: PGD2 ratio (aggregator: antiaggregator) from greater than 5 to less than 2 in all series. In the human series, the ratio decrease was due to an increase in PGD2 production; in the macaque series, PGD2 production increased and TXB2 production decreased. Under basal conditions and at 1 microM AA concentrations, the amounts of prostaglandins and thromboxanes produced by platelets from male and female rhesus macaques were the same. An increase in substrate concentration from 1 microM to 20 microM AA decreased TXB2 production and increased PGD2 production to the same extent in platelets from male and female rhesus macaques. Imidazole increased prostaglandin production and decreased TXB2 production by platelets from both male and female rhesus macaques. The TXB2: PGD2 ratios were reduced below 1.5; there was no difference between the ratios in the two series. In the presence of 1 mM imidazole, greater amounts of prostaglandins and thromboxanes were produced in the male than in the female series. These data indicate that macaque's platelets are a suitable model for the study of AA metabolism in human platelets.

The analgesic effect of self-administered nitrous oxide 50%/oxygen 50% ('Entonox" analgesic apparatus) was compared with air given by the same method in a double-blind trial in 81 patients with myocardial infarction. Self-administered nitrous oxide/oxygen, which was associated with a low frequency of side-effects, proved significantly more effective than air in the early relief of severe cardiac pain, but not in the relief of moderate or slight pain or when administration was continued after ten minutes.

The amino acid content of mozzarella (low moisture, part skim milk) and asadero cheeses was determined by the column chromatographic method. Data from the direct analyses of the mozzarella cheeses were compared with the calculated amino acid composition reported in tables in Agriculture Handbook No. 8-1. Phenylalanine and tyrosine contents were found to be higher in the direct analyses than in the calculated data in Handbook No. 8-1 (1.390 gm and 1.127 gm for phenylalanine, and 1.493 gm and 1.249 gm for tyrosine per 100 gm edible portion, respectively). That is of particular concern in the dietary management of phenylketonuria, in which accuracy in computing levels of phenylalanine and tyrosine is essential.