Top-down causation by information control: from a philosophical problem to a scientific research programme.

It has been claimed that different types of causes must be considered in biological systems, including top-down as well as same-level and bottom-up causation, thus enabling the top levels to be causally efficacious in their own right. To clarify this issue, the important distinctions between information and signs are introduced here and the concepts of information control and functional equivalence classes in those systems are rigorously defined and used to characterize when top-down causation by feedback control happens, in a way that is testable. The causally significant elements we consider are equivalence classes of lower level processes, realized in biological systems through different operations having the same outcome within the context of information control and networks.

Combined cystourethropexy for the treatment of type 3 and complicated female urinary incontinence.

We treated 37 women with type 3 stress urinary incontinence or with an associated complicating factor, such as morbid obesity, a large or proximal diverticulum or a urethrovaginal fistula, via combined transvaginal cystourethropexy. All women with type 3 stress incontinence had failed a previous anti-incontinence operation. Patients in both groups underwent suprapubic needle suspension and an additional bladder neck support procedure. Among 33 patients who underwent preoperative urodynamic studies 30 had stable bladders (90%), while 3 had low pressure detrusor instability (10%). The success rate in achieving continence, including cured and improved patients, was 94.6% with a followup of 3 to 72 months. Four patients (10%) required temporary intermittent catheterization for 3 to 4 weeks but none presented with long-term voiding dysfunction. The added bladder neck support improved our results in these complicated female incontinence cases compared to the standard suprapubic needle suspension procedures alone. The combined procedure currently is our method of choice for treatment of type 3 and other complicated cases of female urinary incontinence.

Urologist's perspectives of single-stage hypospadias repair in the 1980s. Experience of 100 patients.

During the last two decades major advances have been made in techniques of hypospadias repair. Many areas warrant meticulous attention to achieve further satisfactory results. We present areas of technique that have improved our results in genital reconstruction and hypospadias repair in particular. In addition to surgical technique modifications, we present technical refinements of patient positioning, use of cold antibiotic mixed saline, subcutaneous epinephrine at judicious sites, and microsurgical instruments as well as optical magnification and suture material. In genital anomalies, use of plastic surgical techniques with skin grafts and knowledge of the intrinsic vascular supply of the foreskin have further improved the outcome. Since 1982, 100 patients have been followed. Immediate complications total less than 1 percent; late complications total 10 percent including 9 percent fistula rate and 5 percent stenosis rate (urethral or meatal). No loss of skin flap or of neourethra were recorded.

Treatment of vaginal dysplasia and carcinoma in situ with topical 5-fluorouracil.

Seventeen patients, after abnormal Papanicolaou smears, were found to have vaginal lesions ranging from moderate dysplasia to carcinoma in situ. They were evaluated by colposcopy and biopsy. They were treated with topical 5-fluorouracil (5-FU) in the vagina, administered by the patient twice a day for 10 to 14 days. The outlet of the vagina and the vulva were protected with zinc oxide ointment. The patients were followed up with Papanicolaou smears, colposcopy, and biopsy as indicated; all patients have remained free of further dysplasia for 2 to 5 years. The majority of the patients had undergone irradiation for some type of genital malignancy. Topical application of 5-FU in the vagina may prove to be a useful method of therapy for patients with vaginal dysplastic lesions, especially after radiation therapy.