Management of the impacted ureteral calculus

The management of 42 impacted ureteral calculi is reviewed. Impacted stones were defined by the inability to pass a guide wire or catheter on initial attempts. Stones were impacted in the upper ureter in 10 patients, mid ureter in 11 and lower ureter in 21. Upper ureteral stones were treated in 8 patients by extracorporeal shock wave lithotripsy after disimpaction by laser or other techniques. Mid ureteral stones were treated by laser alone in 7 patients and by extracorporeal shock wave lithotripsy after disimpaction in 4. Lower stones were treated by laser in 17 patients and ultrasound in 2. Complications included 3 major and 5 minor perforations, and 4 false passages. Treatment was successful without an open operation in 40 of 42 patients (95%). Our current approach to impacted ureteral calculi involves passing a rigid ureteroscope to the stone, with disimpaction performed by laser fragmentation or other dislodgement maneuvers. Proximal stones or large fragments then are treated by extracorporeal shock wave lithotripsy. Mid ureteral stones are treated similarly, unless they are so fragile that in situ fragmentation may be completed easily. Lower ureteral stones are fragmented in situ, with hard fragments extracted by basket. Alternative treatments for impacted calculi at all levels include unstented in situ extracorporeal shock wave lithotripsy, antegrade ureteroscopy and, finally, an operation.     

Pharmacokinetics of peptide T in patients with Acquired Immunodeficiency Syndrome (AIDS)

1. The pharmacokinetics of Dalal-peptide T-NH2 (peptide T) was determined during phase I clinical trials in patients with acquired immunodeficiecy disease (AIDS) and AIDS related complex (ARC). Drug levels were determined by specific RIA, and in some cases with HPLC analysis, after intraveneous (i.v.) or intranasal (i.n.), via metered sprayer, administration.

2. The plasma kinetics appeared to be bi-phasic with a first compartment half-life of 30 to 60 minutes and a second plasma clearence rate of 4 to 6 hours, observed for both routes of administration. Peptide T, in one individual was confirmed to be present at 6 hrs in plasma, determined after HPLC isolation followed by specific RIA.

3. Bioavailabilty, determined for a 2 mg test dose in six individuals was 9.3 ± 6.9 nmol/L. Peak plasma levels of 41 ± 30 nmol/L after 10 mg i.n., 2.8 ± 5.9 nmol/L after 2mg i.n., and 0.13 ± 0.07 nmol/L after 0.4 mg i.n. were observed. In two individuals tested, peptide T was detected in CSF at levels 20% of the corresponding plasma level 90 and 145 minutes post i.v. administration. Peptide T was not detected in urine. I.N. administration was well tolerated for times up to 21 months.     

Calciphylaxis – a topical overview

'Calciphylaxis', a calcification syndrome associated with ischaemic cutaneous necrosis, is acquired naturally in humans in disease states. It is a life and limb-threatening complication, usually observed in patients with renal disease and secondary hyperparathyroidism, but known to occur in the absence of renal or parathyroid disease. The reported mortality rate, which ranges from 60-80%, relates to wound infection, sepsis and organ failure. It is a small-vessel vasculopathy, which is estimated to occur in about 4% of haemodialysis patients. Clinically, violaceous, reticulate areas of cutaneous necrosis and eschar may be evident, particularly in the extremities. In addition to the clinical picture, a raised calcium phosphorous product, an elevated parathyroid hormone level, radiographic evidence of vessel and soft-tissue calcification and the finding of mural calcification affecting small arteries and arterioles on histopathology help to confirm the diagnosis of this entity which generally has a poor prognosis. A high index of suspicion and an active multidisciplinary management approach, with rigorous attention to wound care and prevention of sepsis, are vital in the management of these patients. In this overview, we discuss the pathophysiology, clinical features and associations, risk factors, diagnosis and management issues relating to calciphylaxis.     

The effects of various indwelling ureteral catheter materials on the normal canine ureter

In an attempt to objectively evaluate the biocompatibility of materials commonly used for ureteral stenting, stent-catheters made of four different materials were placed randomly in 31 ureters of 19 mongrel dogs. Animals underwent urography at four weeks and were sacrificed at six weeks. Mild hydronephrosis was noted in eight instances, essentially unrelated to specific material. Silicone, C-flex and polyurethane stents caused a similar, mild degree of ureteral edema, but ureters stented with Silitek demonstrated fairly marked edema. Epithelial ulceration and erosion, often severe, occurred with all polyurethane stents, and rarely with the three other materials. All materials differed statistically from controls, and C-flex caused less reaction overall than polyurethane, indicating differences in biocompatibility of the various materials which may be relevant to their use in patients undergoing long-term ureteral stenting. In practical terms, these suggest that certain materials, notably silicone and C-flex, are more suitable for ureteral stenting than others.     

Mutations in the retinal guanylate cyclase (RETGC-1) gene in dominant cone-rod dystrophy

The dominant cone-rod dystrophy gene CORD6 has previously been mapped to within an 8 cM interval on chromosome 17p12-p13. The retinal- specific guanylate cyclase gene (RETGC-1), which maps to within this genetic interval and previously was implicated in Leber's congenital amaurosis, was screened for mutations within this family and in a panel of small families and individuals with various cone and cone- rod dystrophy phenotypes. A missense mutation (E837D) was identified in affected members of the CORD6 family, as well as a second missense mutation (R838C) in three other families with dominant cone-rod dystrophy. RETGC-1 is only the fourth gene to be implicated in cone-rod dystrophy and this is the first report of dominant mutations in this gene.      

Influence of environmental temperature on exercise-induced inspiratory muscle fatigue

Exercise in the heat has detrimental effects on circulation that might negatively influence endurance performance. If blood is diverted away from the inspiratory muscles to the skin during exercise in the heat, exercise-induced inspiratory muscle fatigue might be exacerbated. Thus, we hypothesised that prolonged heavy endurance exercise in the heat would impair exercise performance and exacerbate inspiratory muscle fatigue compared to exercise in a thermo-neutral environment. Using a crossover design, seven male endurance trained subjects [mean (SEM) maximum oxygen uptake = 62.2 (1.5) ml·kg^–1·min^–1] were assigned at random to either a group that exercised in the heat at an ambient temperature of 35°C (H) or a group that exercised in the cool at 15°C (C). Maximum inspiratory mouth pressure at zero flow (P ₀), pressure normalised maximum relaxation rate (MRR/P ₀), time constant for the pressure decay (), and maximum inspiratory flow at 30% P ₀ ( ₃₀) were assessed immediately before and reassessed within 2, 30, and 60 min of completing a pre-loaded time trial [40 min at 65% peak power, plus ~30 min time trial] on a cycle ergometer . Group H completed the time trial 432 (135) s slower than group C [2,285 (180) vs 1,852 (122) s, respectively; =24 (8)%, P=0.0094]. Repeat measurements within 2 min post-exercise revealed significant declines in P ₀, MRR/P ₀, , and ₃₀ from baseline values, but no between-group differences were observed. In conclusion, heavy sustained exercise in the heat impaired subsequent time-trial performance but did not exacerbate inspiratory muscle fatigue in endurance-trained subjects.     

Cognitive and family therapies for adolescent depression: treatment specificity, mediation, and moderation

The specificity of cognitive and family therapies, and potential treatment mediators and moderators, was examined in a randomized clinical trial for adolescent depression. After acute treatment, cognitive-behavioral therapy (CBT) exerted specific effects on cognitive distortions relative to either systemic-behavioral family therapy (SBFT) or nondirective supportive therapy (NST). At 2-year follow-up, SBFT was found to impact family conflict and parent-child relationship problems more than CBT; NST and CBT tended to show a greater reduction in anxiety symptoms than SBFT. Nonspecific therapist variables qualified few outcome analyses. No measures of cognitive distortion or family dysfunction mediated or moderated treatment outcome. As in adult studies, relatively few areas of treatment specificity or mediation were identified. The implications of these findings for clinical treatment and research in adolescent depression are discussed.     

Comparison between testosterone oenanthate-induced azoospermia and oligozoospermia in a male contraceptive study. IV. Suppression of endogenous testicular and adrenal androgens

Administration of supraphysiological doses of testosterone to normal men causes inhibition of spermatogenesis, but while most become azoospermic, 30-55% maintain a low rate of spermatogenesis. We have investigated whether there are differences in endogenous androgen production, of testicular and adrenal origin, which may be related to the degree of suppression of spermatogenesis. Thirty-three healthy Caucasian men were given weekly i.m. injections of 200 mg testosterone oenanthate (TE), 18 became azoospermic, while 15 remained oligozoospermic. Urinary excretion of epitestosterone, a specific testicular product, was reduced to <10% of pretreatment values, with no differences between the groups. Similar results were obtained for other markers of testicular steroidogenesis. Urinary and plasma adrenal androgens were also reduced during TE treatment: a statistically significant decrease in both (P < 0.001 and P < 0.05 respectively) was seen in the azoospermic but not oligozoospermic responders. These results suggest that testicular steroidogenesis is decreased to <10% by the administration of supraphysiological doses of exogenous testosterone. Differences in the degree of ongoing steroidogenesis in the testis do not appear to account for incomplete suppression of spermatogenesis, thus differences in androgen metabolism may underlie this heterogeneous response. A small but significant reduction in secretion of adrenal androgens was also detectable, the relevance of which is unclear.