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Metal-injection-molded (MIM) 420 stainless steel is a commonly used material for high-value products such as fuel injector nozzles. However, the trade-offs involved in using different micro-drilling processes on this material are not well-documented in literature. This article presents a micro-drilling study of MIM 420 stainless steel using four candidate processes: micro-electrical discharge drilling (micro-EDD), ultrasonically assisted micro-EDD, micro-mechanical drilling (micro-MD), and ultrasonically assisted micro-MD. The micro-EDD results shows that the use of ultrasonic vibrations significantly improves the overall process time, spark erosion efficiency, and material removal rate of the process. However, this improvement comes at the expense of increased tool wear and surface roughness, especially while machining under high-discharge-energy conditions. The micro-MD results show that the use of ultrasonic vibrations is beneficial in lowering the thrust force, drilling torque, and tool wear a...

Objectives Radiofrequency (RF) energy has recently been employed to destroy human tissue in vivo. The purpose of this study was to investigate the safety of this approach in localized carcinoma of the prostate (CaP) and specifically, the predictability of lesions obtained with radiofrequency interstitial tumor ablation (RITA). Methods Using RITA, a total of 21 lesions were induced in 10 patients with localized CaP (mean age 70.4 years). RF was delivered transperineally under transrectal ultrasound (TRUS) guidance. All patients underwent endorectal magnetic resonance imaging (MRI) before and after treatment. Radical prostatectomy was performed in all patients 1 to 7 days after RITA. Three of the patients were treated with local anesthesia only. The predictability of the thermal lesion was assessed by correlating the findings of intraoperative TRUS, preand post-RITA endorectal MRI, and the histologic examination of the specimen. Results Postoperatively, patients were catheterized for an average of 1.8 days (1 to 3 days). Lesions of 2 × 2 × 2 cm were targeted. Average lesion diameters obtained on MRI were 2.08 ± 0.23 × 2.09 ± 0.36 × 2.28 ± 0.21 cm. Average lesion diameters defined by coagulative necrosis at histologic examination were 2.20 ± 0.23 × 2.10 ± 0.31 × 2.38 ± 0.14 cm. There were no statistically significant differences ( P = 0.377) between average lesion volume on MRI (5.37 ± 1.83 cm 3 ) and average lesion volume at histology (5.86 .63 cm 3 ). No complications or adverse events were noted. Conclusions In this Phase I study, RITA was shown to be safe and feasible, and to result in lesions that were predictable in size and location. MRI accurately visualized and verified the area of coagulative necrosis as documented at histology. The procedure is technically simple and can even be performed under local anesthesia.

A 70-year-old woman with previously asymptomatic pre-excitation presented with reduced level of consciousness and profound hypotension. Electrocardiography revealed pre-excited atrial fibrillation (panel A). The patient required urgent DC cardioversion, subsequently undergoing successful ablation of a left posteroseptal epicardial pathway. Three years previously, because of an incidental finding of pre-excitation on routine electrocardiography, exercise testing had been performed. This had demonstrated gradual diminution …

In summary, 46 renal lithotomies were performed in 40 patients for struvite infection stones. All patients had documented urinary tract infections at the time of surgery; all stones were cultured, demonstrated to contain bacteria and proved crystallographically to be composed primarily of struvite with smaller amounts of apatite. The recurrence rate in a mean followup period of 7 years was 2.5% (one patient). The negligible recurrence rate emphasizes that struvite stones are caused by urea-splitting bacteria, rather than metabolic disorders, and that a comprehensive approach that emphasizes biochemical, bacteriologic, and roentgenographic techniques is more important than the type of surgical procedure used to remove the stones. We believe that our routine of leaving a small polyethylene nephrostomy tube in every patient, combined with postoperative plain-film tomograms regardless of the results of intraoperative radiography, and the liberal use of hemiacidrin irrigation to dissolve any residual struvite particles with their entrapped bacteria, accounts for the virtual absence of stone recurrences in our series.

To the Editor.— The appearance of asymptomatic, bilateral parotid enlargement is widely recognized as a relatively frequent clinical occurrence. It has been noted in Mikulicz syndrome associated with sarcoidosis, in Reiter syndrome, and in several other disorders. However, it is not generally appreciated that this interesting physical finding can also be associated with diabetes mellitus. Report of a Case.— A 50-year-old woman's condition was first diagnosed as adult-onset diabetes mellitus at age 46. After evaluation at another hospital, she was placed on an American Diabetes Association diet and a daily dose of approximately 100 mg of tolbutamide. During the succeeding four years, the patient demonstrated poor diabetic control on numerous occasions and was eventually switched to tolazamide, 500 mg daily. On the day of admission to our hospital, the patient was complaining of dizziness, weakness, and faintness. She gave a history of diabetes, and a blood glucose level determined at