Cryosurgery in dermatology

The aim of this article is to provide current information on the clinical development of cutaneous cryoreaction and the indications, complications and contraindications of cutaneous cryosurgery. Successful cutaneous cryosurgery requires rapid freezing and slow thawing, minimum tissue temperatures of -25 degrees C to -60 degrees C and, in malignant lesions, repeated freeze-thaw cycles. Frozen tissue reacts with peripheral erythema immediately following thawing, and consequently with oedema, bulla formation, exudation, mummification, and usually heals with a fine atrophic scar within a 4-week period. Cryosurgery is now considered the treatment of choice in hypertrophic scars and keloids, granuloma annulare and capillary haemangioma of the newborn. It also represents a valuable alternative therapy for various skin diseases, including common warts, solar lentigo, actinic keratoses, superficial basal cell carcinoma and Kaposi's sarcoma. Cryosurgery is a safe regimen with only a few adverse effects and contraindications. Pain during and/or shortly after treatment, bulla formation and local oedema are the major, temporary adverse effects; lesional hypopigmentation and/or peripheral hyperpigmentation is the most common by occurring long-term complication.     

Cryosurgery in cutaneous leishmaniasis

Thirty patients with cutaneous leishmaniasis were treated with cryotherapy using a CO2 cryomachine and all were cured without noticeable scarring within 4-5 weeks, with no relapse. Histopathological examination showed that cryotherapy eradicated all parasites in less than 1 hour. Leishmania tropica, L. ethiopica and L. brasiliensis are all markedly thermosensitive and thus cryotherapy seems parasiticidal to all types. Adequate cryotreatment of cutaneous leishmaniasis will preclude the development of mucocutaneous extension, and its use in mucocutaneous disease is also recommended.     

Cryosurgery for hemangiomas

Children with the long QT syndrome (LQTS) are prone to life threatening ventricular arrhythmias. These arrhythmias may result in syncope and seizures that are often attributed incorrectly to a seizure disorder or to common fainting. The untreated mortality for symptomatic children with the LQTS is high but is improved significantly with therapy. Paediatricians should be aware of the presentations of the syndrome. Recommendations for screening for the syndrome are given.     

Cryosurgery of the ureter in dogs

The effect of cryosurgery on the ureter has been studied in dogs. A single 1- or 2-min cryosurgical exposure produced stricture in two of eight animals. A tumoricidal cryosrugical dose consisting of three, 2-min exposures caused stricture in six of eight dogs. Histopathologic examination of the ureter after repetitive cryosurgery showed progressive, persistent loss of smooth muscle, fibrosis of the lamina propria, and early loss with subsequent regeneration of the transitional epithelium. Although there was no loss of ureteral integrity, the possibility of permanent ureteral damage should be considered with the use of cryosurgery.     

Lasers in urology

Ever since Mulvany first described use of Ruby laser for lithotripsy, urologists have been exploiting every possible application of this technology. Laser lithotripsy in the 1980s and now laser prostatectomy in the 1990s have dominated laser usage in urology. Applications of lasers for superficial lesions (e.g., condylomata acuminata and carcinoma of penis) have found an established role. Interests in laser welding, photodynamic therapy and fluorescence continues to grow and evolve. The laser industry at the same time is striving to provide more efficient lasers. High power lasers (Holmium:YAG, KTP:YAG) and laser machines combining double wavelengths (Nd:YAG and KTP, Ho: YAG and Nd:YAG) are commercially available. Diode lasers with their portability and reliability qualities can now provide high output powers in various wavelengths. Here, we have reviewed different lasers, laser tissue interaction and clinical laser applications relevent to urology.     

Computer modeling in urology

A family of structurally related intrinsic membrane proteins (facilitative glucose transporters) catalyzes the movement of glucose across the plasma membrane of animal cells. Evidence indicates that these proteins show a common structural motif where approximately 50% of the mass is embedded in lipid bilayer (transmembrane domain) in 12 alpha-helices (transmembrane helices; TMHs) and accommodates a water-filled channel for substrate passage (glucose channel) whose tertiary structure is currently unknown. Using recent advances in protein structure prediction algorithms we proposed here two three-dimensional structural models for the transmembrane glucose channel of GLUT1 glucose transporter. Our models emphasize the physical dimension and water accessibility of the channel, loop lengths between TMHs, the macrodipole orientation in four-helix bundle motif, and helix packing energy. Our models predict that five TMHs, either TMHs 3, 4, 7, 8, 11 (Model 1) or TMHs 2, 5, 11, 8, 7 (Model 2), line the channel, and the remaining TMHs surround these channel-lining TMHs. We discuss how our models are compatible with the experimental data obtained with this protein, and how they can be used in designing new biochemical and molecular biological experiments in elucidation of the structural basis of this important protein function.     

Imaging in pediatric urology

A multitude of disorders of the genitourinary tract can occur in children. Although some entities may be diagnosed clinically, radiologic imaging is often necessary for diagnosis and management. The radiologic work-up has been discussed using a problem-oriented approach in five clinical situations: urinary tract infection, hydronephrosis or hydroureter, trauma, swollen scrotum, and hematuria. This discussion provides some general guidelines, although the evaluation of each child may need to be individualized depending on their specific clinical symptomatology.     

Antimicrobial prophylaxis in urology

Antimicrobial prophylaxis in surgery has proven to be effective in controlled randomized trials. Usage in Urology is known at least since the '30s although its effectiveness has only become known since 1979. METHODS: Review of literature related to surgical antibiotic prophylaxis, more specifically urological surgery, basically from 1991 to 1995, but without overlooking those papers that have become classics due to their impact. RESULTS AND CONCLUSIONS: Efficacy of antimicrobial prophylaxis in urological surgery is nowadays beyond all doubt. Usage is indicated in the presence of sterile urine and dosage must be short, in single dosis in the immediate pre-operative or within 24 hours after the procedure. However, there is a number of issues that deserve to be treated in more detail for better understanding. Those are the establishment of adequate prophylactic regimes in renal transplantation and the use of antimicrobials based on their pharmacokinetic characteristics to optimize the prophylactic purpose.     

Role of biofilm in urology

The particular organization of bacteria as a biofilm on surfaces plays an essential role in urology because of the increasing use of prosthetic materials. Although the biocompatibility of the various materials used is now more effectively controlled, colonization of surfaces by microorganisms is frequent and the formation of a biofilm is responsible for difficulties encountered during treatment of prosthetic infections. The problems concerning the detection and eradication of biofilm led the authors to propose a brief review of the growing understanding of biofilm in urology over the last five years.     

Legal problems in everyday urology

Docetaxel is a new taxoid antineoplastic agent with clinical efficacy especially in breast cancer. One of the most distressing side-effects induced by docetaxel is alopecia. We studied the prevention of alopecia by using a cold cap in 98 patients receiving 100 mg/m2 docetaxel by 1 h i.v. infusion every 3 weeks. One patient was lost to follow-up. 83 patients (86%) were evaluated as a success to the cold cap, as they presented WHO grade alopecia < or = 2 and no need to wear a wig. 14 patients (14%) had to wear a wig; among them; 7 patients withdrew before the evaluation at three cycles. The cold cap is a very effective technique with minimal side-effects for docetaxel-treated patients.     

Current clotting concepts in urology

A modern outline of the physiology of coagulation, a simple approach to the use of laboratory investigation for patients with possible clotting disorders in unexplained hematuria and several illustrative cases are presented. The diagnosis and management of localized fibrinolysis in the genitourinary tract and intravascular coagulation as possible causes of post-prostatectomy hemorrhage are discussed. A minimum of a platelet count, fibrinogen assay and, if possible, measurement of fibrinogen-related antigens should be obtained before administration of epsilon aminocaproic acid.