Vesicoureteral reflux and ureteropelvic junction obstruction: association, treatment options and outcome

PURPOSE: We investigated the association, treatment options and outcomes of patients with ureteropelvic junction obstruction and concomitant vesicoureteral reflux. MATERIALS AND METHODS: We analyzed 6,790 consecutive pediatric urology records at our university. Treatment options included observation, and primary pyeloplasty, ureteroneocystostomy and nephroureterectomy. Hydronephrosis, reflux and obstruction were judged as resolved, improved, unchanged or worse. RESULTS: A total of 1,140 patients had vesicoureteral reflux, 224 had ureteropelvic junction obstruction and 41 had both conditions (39 ipsilateral and 6 contralateral kidneys). There was no increased risk of obstruction in patients with reflux when all grades of reflux were grouped (odds ratio 1.26, confidence interval 0.91 to 1.71). In contrast, subgroup analysis of patients with high grade reflux demonstrated a 5-fold increased risk of obstruction (odds ratio 5.0, confidence interval 2.4 to 10.8). One patient was lost to followup. Observation of 6 kidneys led to resolution of reflux in 3 (50%), resolution of obstruction in 3 (50%) and resolution or improvement of hydronephrosis in 4 (67%). Primary pyeloplasty was done on 29 kidneys with 10 (35%) requiring subsequent ureteroneocystostomy. At latest followup hydronephrosis resolved or improved in 24 patients (83%), vesicoureteral reflux resolved or improved in 19 (66%) and ureteropelvic junction obstruction resolved in all. Primary ureteroneocystostomy was performed on 5 kidneys, all of which required subsequent pyeloplasty. Hydronephrosis resolved in 3 patients (60%), and reflux and obstruction resolved in all. Two patients treated with primary nephroureterectomy, and 1 who underwent concomitant pyeloplasty and ureteroneocystostomy have had no subsequent urological problems. One patient awaits primary pyeloplasty. CONCLUSIONS: High grade vesicoureteral reflux is associated with ureteropelvic junction obstruction. No association with low or intermediate grade reflux was demonstrated. While some patients may be monitored expectantly, in our series pyeloplasty or nephrectomy was required in 81% and ureteroneocystostomy was required in 36%. In no case did primary ureteroneocystostomy protect against the subsequent need for pyeloplasty.     

Alternative measures of pesticide use

tRNA (m5U54)-methyltransferase (RUMT) catalyzes the S-adenosylmethionine-dependent methylation of uridine-54 in the T psi C-loop of all transfer RNAs in E. coli to form the 54-ribosylthymine residue. However, in all tRNA structures, residue 54 is completely buried and the question arises as to how RUMT gains access to the methylation site. A 17-mer RNA hairpin consisting of nucleotides 49-65 of the T psi-loop is a substrate for RUMT. Homonuclear NMR methods in conjunction with restrained molecular dynamics (MD) methods were used to determine the solution structure of the 17-mer T-arm fragment. The loop of the hairpin exhibits enhanced flexibility which renders the conventional NMR average structure less useful compared to the more commonly found situation where a molecule exists in predominantly one major conformation. However, when resorting to softer refinement methods such as MD with time-averaged restraints, the conflicting restraints in the loop can be satisfied much better. The dynamic structure of the T-arm is represented as an ensemble of 10 time-clusters. In all of these, U54 is completely exposed. The flexibility of the T psi-loop in solution in conjunction with extensive binding studies of RUMT with the T psi C-loop and tRNA suggest that the specificity of the RUMT/ tRNA recognition is associated with tRNA tertiary structure elements. For the methylation, RUMT would simply have to break the tertiary interactions between the D- and T-loops, leading to a melting of the T-arm structure and making U54 available for methylation.     

Elucidation of mitochondrial effects by tetrahydroaminoacridine (tacrine) in rat, dog, monkey and human hepatic parenchymal cells

Tetrahydroaminoacridine (tacrine) causes morphological and functional changes in the endoplasmic reticulum, ribosomes, and mitochondria in the liver of humans and animals. In order to investigate species differences as well as to understand the morphological changes, we examined the effects of tacrine on respiration and electron transport in mitochondria isolated from rat, dog, monkey, and human liver. Tacrine produced significantly decreased respiratory control ratios (RCR) in all species at concentrations ranging from 5 to 25 microg/ml. Human mitochondria were more sensitive to tacrine effects with RCR decreased 24% at 5 microg/ml while other species were unaffected at this concentration. The tacrine effects were characterized by increased hepatic mitochondrial State 4 respiration in rats and decreased State 3 respiration in humans. Mitochondria from aged rats were more sensitive to the effects of tacrine than mitochondria from young animals, with significantly decreased RCR at 10 microg/ml in aged rats while mitochondria from young rats were unaffected at this concentration. Concomitant with the respiratory changes, mitochondrial DNA synthesis was impaired. Since tacrine undergoes extensive biotransformation, we also explored the possibility that metabolites could exert detrimental effects. The ranking order of potency for decreasing RCR caused by monohydroxylated metabolites was: tacrine > 4-OH and 7-OH > 2-OH, 1-OH, and velnacrine with the latter group of metabolites having no effect on mitochondrial respiration at concentrations up to 50 microg/ml. In vivo administration of 20 mg/kg tacrine to rats for up to 20 days caused a paradoxical increase in RCR and P/O on Day 1 and decreased RCR on Days 9 and 20, the later findings being consistent with in vitro data. From these data we propose that tacrine does not necessarily have to be metabolized to exert effects on mitochondria at different sites in the electron transport chain that differ among species. These effects are exacerbated in mitochondria from older animals and humans appear to be more sensitive than the laboratory animals studied.     

Modeling flotation separation in a semi-batch process

A model for a semi-batch flotation separation process has been developed, based on available microprocess probabilities, and compared to experimental data obtained using a WEMCO laboratory flotation cell. In general, the model predicts the correct experimental trends. In many cases, the model also predicts removal efficiency very well. Parametric studies reveal that the model predictions are sensitive to a stability parameter, the turbulent energy density in the flotation cell, the contact angle between the solid particle and fluid, and the ratio of initial-to-critical film thickness.     

Lingual ischemia following tongue entrapment in a glass bottle

A 10-year-old, previously healthy female presented to the emergency department via emergency medical service transport, with her tongue tightly entrapped inside a glass bottle (9 oz, Yoohoo brand of chocolate drink). The tongue was massively edematous and ecchymotic due to impaired venous return from constriction by the neck of the bottle. After repeated attempts at mechanically reducing the tongue out of the bottle, a professional glazier was contacted, who was able to remove the bottle in the operating room with a steel glass cutter. Needle evacuation of a small hematoma was then performed to decrease the pressure ischemia to the tongue, which began to improve quickly.