Incidence of pathologic postobstructive diuresis after resolution of ureteropelvic junction obstruction with a normal contralateral kidney

INTRODUCTION

Postobstructive diuresis (POD) after unilateral pyeloplasty or percutaneous nephrostomy (PCN) tube insertion for ureteropelvic junction obstruction (UPJO) in patients with a normal contralateral kidney is not well described.

OBJECTIVE

The objective of this study was to determine the incidence and characteristics of POD after relief of unilateral UPJO in patients with a normal contralateral kidney.

STUDY DESIGN

Children who underwent a unilateral pyeloplasty or PCN for UPJO from 2010 to 2017 with a normal contralateral kidney were retrospectively reviewed. Postobstructive diuresis was defined as urine output (UO) of >300% of expected UO. Patients with a solitary kidney or those who underwent bilateral pyeloplasty or bilateral PCN tube placement were excluded.

RESULTS

Out of 396 children meeting inclusion criteria, seven (1.8%) developed POD (4 after pyeloplasty and 3 after PCN tube placement). Median age at intervention was 1.7 years (range 11 days-18 years); median weight was 11.4 kg (range 3.7-54.2 kg). Postobstructive diuresis was more likely to occur in patients with grade 4 hydronephrosis (3.0%) and larger kidneys and if a PCN tube was placed before pyeloplasty. There was no significant difference in age, gender, kidney laterality, or function between those who developed POD and those who did not. Postobstructive diuresis was managed with additional intravenous fluids and electrolyte monitoring. Median initial postprocedure UO was 5.9 mg/kg/hr (range 3.2-10.0 mg/kg/hr). In five children who underwent PCN in whom UO could be differentiated between kidneys, median initial postprocedure UO was 6.1 mg/kg/hr (range 2.5-9.1 mg/kg/hr) from the affected side and 0.8 mg/kg/hr (range 0.4-0.9 mg/kg/hr) from the unaffected side. The median length of time to resolution of POD was 3 days (range 2-4 days). One patient developed significant acidosis and lethargy that improved with intravenous fluid management. Mild hyponatremia developed in two, hypokalemia in one, hypophosphatemia in one, acidosis in one, and hypoglycemia in 1 patient.

DISCUSSION

A low but clinically significant risk of POD occurring after relief of unilateral UPJO in children with a normal contralateral kidney is described. Limitations include retrospective analysis and small sample size due to the rarity of the condition.

CONCLUSION

Postobstructive diuresis after decompression of UPJO in patients with a normal contralateral kidney is a rare event (1.8%). However, POD does occur, and patients should be carefully monitored after these procedures given the potential for significant dehydration and electrolyte disturbances.

Long-term follow-up of composite bladder augmentation incorporating stomach in a multi-institutional cohort of patients with cloacal exstrophy

INTRODUCTION

Composite bladder augmentation, incorporating gastric and bowel segments, has the theoretical advantage of metabolic neutrality while potentially avoiding the morbidities of gastrocystoplasty, such as hematuria-dysuria syndrome. The most common indication for this operation is a paucity of bowel, such as in cloacal exstrophy. Despite several early descriptive studies of this technique, there are no reports, to date, of long-term follow-up in this population.

OBJECTIVE

To describe the outcomes of composite bladder augmentation utilizing stomach in a cohort of cloacal exstrophy patients.

MATERIALS AND METHODS

A retrospective review of cloacal exstrophy patients who underwent composite bladder augmentation from 1984 to 2006 at two institutions was performed. The incidence of mortality and morbidities related to augmentation was evaluated.

RESULTS

Eleven patients with cloacal exstrophy underwent composite bladder augmentation. Median age at initial augmentation was 6.4 years (interquartile range (IQR) 4.4-9.1). Median follow-up was 13.2 years (IQR 11.2-24.6). The Summary table describes the types of composite bladder augmentations. Of the three patients with pre-operative metabolic acidosis, two improved with composite bladder augmentation and one developed metabolic alkalosis. Three developed hematuria-dysuria syndrome: one improved with staged ileocystoplasty, and two had persistent symptoms successfully treated with H2 receptor blockers. Two of 11 developed symptomatic bladder stones. There were no reported bladder perforations, bladder malignancies, conversions to incontinent urinary diversions, or deaths.

CONCLUSION

With long-term follow-up, very few patients developed metabolic acidosis/alkalosis after composite bladder augmentation. The composite bladder augmentation will continue to be used in patients with cloacal exstrophy, in order to minimize the impact on the pre-existing short gut in these patients.

Morphological engineering of Streptomyces hygroscopicus var. geldanus: regulation of pellet morphology through manipulation of broth viscosity

Actinomycetes, especially members of the genus Streptomyces, are responsible for producing the majority of known antibiotics. The production of antibiotics by filamentous organisms is often dependent on the morphology and size distribution of the pellet population within the culture. Particle interaction and subsequent pellet formation are primarily dependent on the rate of collision of particles in culture, which is in turn, a function of fluid turbulence. The microbial polysaccharide xanthan gum was used to artificially regulate the apparent viscosity (mu(a)) of S. hygroscopicus fermentation broths with the aim of controlling particle interaction, aggregation and hence pellet formation. An increase in both pellet count and biomass concentration from approximately 2,000 to 8,000 pellets ml(-1) and 0.9-2.1 g l(-1) dry weight of biomass, as well a decrease in the mean pellet volume from 0.014 to 0.004 mm(3) was observed in cultures supplemented with 3 g l(-1) xanthan gum. The addition of xanthan gum significantly alters fluid rheology by increasing the mu(a). Counter-intuitively, an increase in the mu(a) within the experimental range examined resulted in an increase in the rate of gas-liquid mass transfer. This was attributed to the predominantly diffusive nature of oxygen transfer in shake flask cultures.

Development of a robust microtiter plate-based assay method for assessment of bioactivity

A microtiter plate-based assay was developed for the quantitative monitoring of bioactive compound production in Streptomyces hygroscopicus fermentation samples. The method reported demonstrates the successful application of the theories of disk diffusion based methods of bioactivity assessment, to a microtiter assay for high throughput analysis. The assay method facilitates the generation of the dose-response curve of test organisms (Escherichia coli, Bacillus subtilis and Saccharomyces cerevisiae) to a bioactive compound. Using this dose-response curve, the method facilitates definition of three distinct Minimum Inhibitory Concentration (MIC) values for use in the characterisation of the bioactive attributes of a sample. The assay uses established standard procedures to facilitate adaptation of the assay for use with a wider range of test microorganisms. Errors due to the assumption of a linear relationship between turbidity and biomass concentration are also reduced, due to incorporation of a step to convert turbidity to biomass concentration, for use in the calculation of bioactivity.

Physical and functional interactions between the herpes simplex virus UL15 and UL28 DNA cleavage and packaging proteins

Herpes simplex virus (HSV) DNA is cleaved from concatemers and packaged into capsids in infected cell nuclei. This process requires seven viral proteins, including UL15 and UL28. UL15 expressed alone displays a nuclear localization, while UL28 remains cytoplasmic. Coexpression with UL15 enables UL28 to enter nuclei, suggesting an interaction between the two proteins. Additionally, UL28 copurified with UL15 from HSV-infected cells after ion-exchange and DNA affinity chromatography, and the complex sedimented as a 1:1 heterodimer upon sucrose gradient centrifugation. These findings are evidence of a physical interaction of UL15 and UL28 and a functional role for UL15 in directing UL28 to the nucleus.

Prothrombin Greenville, Arg517-->Gln, identified in an individual heterozygous for dysprothrombinemia

A 64-year-old white male was referred for evaluation of prolonged prothrombin time (PT) and activated partial thromboplastin time (aPTT) obtained before elective surgery with initial PT and PTT results of 14.9 and 38.4 seconds, respectively, which corrected to normal in 1:1 mixes with normal plasma. Functional prothrombin assay indicated a level of 51% with thromboplastin as an activator. The prothrombin antigen was 102%. This discordance in the functional and immunologic prothrombin levels was evidence for dysprothrombinemia. Western blotting showed that thrombin was formed at a normal rate in diluted plasma consistent with a mutation within the thrombin portion of prothrombin. DNA was isolated from leukocytes and the thrombin exons were amplified by polymerase chain reaction, cloned, and sequenced. For exon 13, eight clones were sequenced with four clones showing a point mutation in the codon for Arg517, which would result in substitution by Gln. Arg517 is part of the Arg-Gly-Asp(RGD) sequence in thrombin and contributes to an ion cluster with aspartic acid residues 552 and 554. Mutation at this residue most probably distorts the structure of the Na+ binding site in thrombin. This is the first report indicating the critical role of Arg517 in the normal physiological interaction of thrombin with fibrinogen. This dysprothrombin is designated Prothrombin Greenville.

The UL6 locus of pseudorabies virus and its homology to oncogenic herpesviruses

The UL6 locus of pseudorabies virus (PRV) was analyzed to reveal a gene cluster with homology to herpes simplex virus UL5, UL6, UL7 and UL8, Epstein-Barr virus BBRF1 and BBRF2, and Kaposi sarcoma-associated herpes virus ORF43 and ORF42. The noncoding region between PRV UL7 and UL8 contained 16 copies of a 14 bp T + C-rich repeat element. The mRNA start sites for UL6 and UL7 were mapped by primer extension and UL6 was expressed in vitro. The mobility of the in vitro-expressed UL6 protein correlated with the predicted mass of 66 kDa. The relationship and potential significance of the UL6 locus with the corresponding sequences in oncogenic herpesviruses is discussed.

1991 outlook: progress will require partnerships, improved productivity--roundtable discussion

To address the myriad problems and challenges in the next year, the operative word will be partnership. That's according to members of Modern Healthcare's editorial advisory board in their discussion of the healthcare industry in 1991. The experts see the need for hospitals, physicians and the business community to team up to control costs, solve staffing woes and take initial steps toward healthcare reform.