Urinary aquaporin-2 excretion in preterm and full-term neonates

The study was undertaken to define the role of aquaporin-2 (AQP2) in renal concentrating performance by measuring urinary AQP2 excretion and urine osmolality in healthy preterm and full-term neonates during early postnatal life. Random urine samples were obtained from 9 full-term newborn infants (mean birth weight 3,218 g, mean gestational age 39.2 weeks) at postnatal ages of 1, 3 and 5 days. Five premature infants with a mean birth weight of 1,570 g and mean gestational age of 30.6 weeks were studied at the end of the 1st week and then weekly up to the 6th week. Urine osmolality (Knauer osmometer), creatinine (modified Jaffé's method) and AQP2 concentrations (radioimmunoassay) were measured. In full-term neonates, urinary AQP2 excretion showed no consistent changes over the age period studied, while urine osmolality decreased significantly with advancing age. In premature infants, urinary AQP2 excretion remained practically unchanged during the first 4 weeks followed by an abrupt increase thereafter. Urine osmolality did not follow the developmental pattern of AQP2 excretion; its mean values varied only from 78 +/- 39 to 174 +/- 146 mosm/l during the experimental period. It is concluded that during the early postnatal period, urinary AQP2 excretion does not serve as a direct marker of the renal action of AVP and the renal capacity to concentrate urine.     

Seromuscular gastrocystoplasty in dogs

INTRODUCTION: The aim of this study was to investigate the feasibility of seromuscular gastrocystoplasty (SGCP) in an animal model and to compare it to conventional gastrocystoplasty (CGCP). MATERIALS AND METHODS: CGCP and SGCP (using gastric segments without mucosa) were each performed in 6 dogs. In both procedures, two-thirds of the dome of the bladder were excised and the gastric segment anastomosed to the bladder remnant. Cystography, cystomanometry, measurements of urine pH, and gross and microscopic pathological studies were carried out preoperatively, and postoperatively, at 6 and 12 weeks. RESULTS: All seromuscular gastric segments proved viable, and 6 weeks after the operation they were covered by a thin layer of transitional epithelium, which had gradually thickened by the end of the 12-week follow-up. There was no difference in bladder capacity and compliance between the two groups, however, fasting urinary pH values were higher (less acidic) in the SGCP group. CONCLUSIONS: Stripping off the mucosa of the gastric segment appears to stop hydrochloric acid secretion, thereby lessening the possible risk of ulceration, perforation, dysuria-haematuria, metaplasia and malignancy. The uroepithelium overgrowth of the seromuscular gastric segments might provide a more physiological neo-bladder than when using full-thickness gastrocystoplasty.     

Intermediate results of surgical bladder augmentation in children

The most common origin of the urinary incontinence are the myelodysplasia and congenital urogenital malformations in childhood. Surgical augmentation of the urinary bladder with or without continent diversion, may be indicated in case of unsatisfactory result of all other conservative treatments. Between 1987-2000 bladder augmentation or substitution was carried out with large bowel or gastric segment in 37 patients. The age at surgery was between 6-21 yrs, (mean 12.3 yrs). The authors discuss the results of the 30 patients in whom follow up was at least 1 yr (12-113 months, mean 43 months). The urinary incontinence could be solved in 24/30 of the children, 6/30 remained in the same condition without worsening any of them. In 11/30 patients complication was not observed at all, but in 19/30 further surgeries were necessary in 30 times, mainly due to stone formation. The authors state that the augmentation cystoplasty is a useful method for the creation of a low pressure urinary reservoire which with or without a continent diversion may solve the urinary incontinence, however the patients need a lifelong follow-up due to the possible long-term risks.     

Novel druggable hot spots in avian influenza neuraminidase H5N1 revealed by computational solvent mapping of a reduced and representative receptor ensemble

The influenza virus subtype H5N1 has raised concerns of a possible human pandemic threat because of its high virulence and mutation rate. Although several approved anti-influenza drugs effectively target the neuraminidase, some strains have already acquired resistance to the currently available anti-influenza drugs. In this study, we present the synergistic application of extended explicit solvent molecular dynamics (MD) and computational solvent mapping (CS-Map) to identify putative 'hot spots' within flexible binding regions of N1 neuraminidase. Using representative conformations of the N1 binding region extracted from a clustering analysis of four concatenated 40-ns MD simulations, CS-Map was utilized to assess the ability of small, solvent-sized molecules to bind within close proximity to the sialic acid binding region. Mapping analyses of the dominant MD conformations reveal the presence of additional hot spot regions in the 150- and 430-loop regions. Our hot spot analysis provides further support for the feasibility of developing high-affinity inhibitors capable of binding these regions, which appear to be unique to the N1 strain.     

Ectopic ureter in infancy and childhood

Two infants, 7 children and 1 young woman have been surgically treated for ureteral ectopy in the Departments of Paediatrics and of Urology of the Medical University of Pécs over the last 15 years (1974-1989). The girl/boy ratio was 8/2. In girls, who were otherwise toilet-trained with a normal voiding pattern, constant wetting and urinary infection were the leading clinical findings. The site of ureteral drainage was the vestibule in 4 patients, the urethra in 3, the vagina in 1, the prostatic utricle in 1, and it could not be determined in 1 girl. Diagnosis was based on intravenous urography, voiding cystourethrography, ultrasonography, isotope scan, endoscopy and filling up of the bladder with a methylene blue solution. The diagnosis was more obscure when the ectopic ureter drained a poorly functioning kidney. Considering that in ectopy with duplicated system the upper pole renal segment is almost always destroyed, upper pole nephrectomy and proximal ureterectomy are advocated. In 1 neonate with esophageal atresia and tracheo-esophageal fistula ultrasonography detected the ureteral malformation. In 1 girl bilateral single ureteral ectopy was found.     

Breast MRI: Early experience with a 3-D fat-suppressed Gradient Echo Sequence in the evaluation of breast lesions

The early clinical experience with a 3-Dimensional Fourier Transform Gradient Echo sequence with fat suppression in the evaluation of breast masses is reported. Ten female patients with breast malignancies were pre-operatively evaluated with this sequence and the results compared with the pathological specimens. The scanning protocol included a noncontrast sequence followed by an immediate post-contrast sequence (completed 4.5 min after intravenous contrast injection) and a delayed sequence. Images were assessed for maximum lesion and parenchymal enhancement, lesion size and additional enhancing abnormalities. In six patients, malignant masses enhanced maximally on the immediate post-contrast sequence with parenchyma enhancing maximally on delayed images. In three cases, there was preferential enhancement of malignant lesions over normal parenchyma but to a similar degree on both post-contrast sequences. In one case, both the lesion and parenchyma enhanced maximally on the delayed sequence. Magnetic resonance assessed lesion size accurately and also detected satellite malignancies in one case. However, lesion grade, associated in situ carcinoma and lymphovascular invasion did not impact on lesion enhancement. In this small series, a contrast-enhanced, fat-suppressed 3-D Gradient Echo Sequence detected breast carcinoma with high sensitivity. The technique holds promise but further evaluation is required.     

Inflammatory bowel disease and predisposition to osteopenia

The prevalence of osteopenia in children with inflammatory bowel disease (IBD) is unknown. The effect of nutritional state, disease activity, and steroid therapy on bone mineral content (BMC) of whole body, lumbar spine, and left femoral neck measured by dual energy x ray absorptiometry in 32 children with IBD was assessed by comparison with 58 healthy local school children. Using the control data, a predicted BMC was calculated taking into account bone area, age, height, weight, and pubertal stage. The measured BMC in children with IBD was expressed as a percentage of this predicted value (% BMC). Mean (SD) % BMC was significantly reduced for the whole body and left femoral neck in the children with IBD (97.0 (4.5)% and 93.1 (12.0)% respectively, p < 0.05). Of the children with IBD, 41% had a % BMC less than 1 SD below the mean for the whole body and 47% at the femoral neck. Reduction in % BMC was associated with steroid usage but not with the magnitude of steroid dose, disease activity, or biochemical markers of bone metabolism. In conclusion, osteopenia is relatively common in childhood IBD and may be partly related to the previous use of steroids.