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Stephen A. Koff

Bio: Stephen A. Koff is an academic researcher from Ohio State University. The author has contributed to research in topics: Hydronephrosis & Urethra. The author has an hindex of 29, co-authored 47 publications receiving 3088 citations. Previous affiliations of Stephen A. Koff include Nationwide Children's Hospital & American Urological Association.

Papers
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Journal ArticleDOI
TL;DR: Dysfunctional elimination syndromes are common and are often unrecognized in children with primary reflux and are associated with delayed reflux resolution and an increased rate of breakthrough urinary tract infection, which leads to reimplantation surgery.

453 citations

Journal ArticleDOI
TL;DR: Unilateral newborn hydronephrosis appears to be relatively benign and in most instances dilatation and renal function improve with time and close followup is necessary to identify the subgroup of less than 25% of infants with obstruction because prompt pyeloplasty will prevent permanent loss of renal function.

292 citations

Journal ArticleDOI
TL;DR: All traditional diagnostic tests for assessing obstruction, including diuretic renography washout pattern, were inaccurate in diagnosing obstruction and predicting which kidney would deteriorate, and it appears safe to follow neonatal unilateral hydronephrosis closely and nonoperatively.

258 citations

Journal ArticleDOI
TL;DR: It is suggested that many newborn kidneys with severe hydronephrosis are not obstructed despite even profound initial decreases in renal function and that traditional tests for diagnosing obstruction are inaccurate in this age group.

166 citations

Journal ArticleDOI
TL;DR: The preceding discussion has identified many of the frustrating difficulties in the definition, diagnosis, and determination of the significance of obstruction in hydronephrosis, and doubts have been raised about the indications for surgical intervention.

153 citations


Cited by
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Journal ArticleDOI
TL;DR: This paper aims to identify studies which were relevant to one or more key questions and which were primary analytic research, systematic review or meta-analysis and written in English.
Abstract: AND FULL-TEXT SCREENING To identify studies which were a) relevant to one or more key questions b) primary analytic research, systematic review or meta-analysis and c) written in English DATA EXTRACTION AND SYNTHESIS Data abstracted into evidence tables; study quality assessed DRAFT RECOMMENDATIONS Strength of evidence graded; summaries and recommendations drafted FINALIZE RECOMMENDATIONS Recommendations finalized; guideline published

1,109 citations

Journal Article
TL;DR: There is no evidence that using antiseptics or disinfectants selects for antibiotic-resistant organisms in nature or that such mutants survive in nature.
Abstract: The issue of whether low-level tolerance to germicides selects for antibiotic-resistant strains is unsettled but might depend on the mechanism by which tolerance is attained. For example, changes in the permeability barrier or efflux mechanisms might affect susceptibility to both antibiotics and germicides, but specific changes to a target site might not. Some researchers have suggested that use of disinfectants or antiseptics (e.g., triclosan) could facilitate development of antibiotic-resistant microorganisms 334, 335, . Although evidence in laboratory studies indicates low-level resistance to triclosan, the concentrations of triclosan in these studies were low (generally <1 μg/mL) and dissimilar from the higher levels used in antimicrobial products (2,000–20,000 μg/mL) 364, . Thus, researchers can create laboratory-derived mutants that demonstrate reduced susceptibility to antiseptics or disinfectants. In some experiments, such bacteria have demonstrated reduced susceptibility to certain antibiotics . There is no evidence that using antiseptics or disinfectants selects for antibiotic-resistant organisms in nature or that such mutants survive in nature. ). In addition, the action of antibiotics and the action of disinfectants differ fundamentally. Antibiotics are selectively toxic and generally have a single target site in bacteria, thereby inhibiting a specific biosynthetic process. Germicides generally are considered nonspecific antimicrobials because of a multiplicity of toxic-effect mechanisms or target sites and are broader spectrum in the types of microorganisms against which they are effective 344, .

914 citations

Journal ArticleDOI
TL;DR: A system to grade upper tract dilatation or hydronephrosis (HN) imaged by ultrasound has been developed and is being used by SFU members in 36 institutions and the appearance of the calices, renal pelvis and renal parenchyma are key in determining the grade of HN.
Abstract: The Society for Fetal Urology (SFU) was founded in 1988 to study the postnatal evolution of prenatally detected anomalies of the urinary tract by following those neonates whose prenatal studies have brought them to medical attention while asymptomatic. The SFU has attempted to standardize methods of performing and grading the ultrasound and radionuclide examinations in this population. A system to grade upper tract dilatation or hydronephrosis (HN) imaged by ultrasound has been developed and is being used by SFU members in 36 institutions. The appearance of the calices, renal pelvis and renal parenchyma are key in determining the grade of HN and are illustrated in this article.

877 citations

Book ChapterDOI
TL;DR: Data emerging from prospective surveillance studies suggest that most human leptospiral infections in endemic areas are mild or asymptomatic, and patients progressing to multisystem organ failure have widespread hematogenous dissemination of pathogens.
Abstract: Leptospirosis is a widespread and potentially fatal zoonosis that is endemic in many tropical regions and causes large epidemics after heavy rainfall and flooding. Infection results from direct or indirect exposure to infected reservoir host animals that carry the pathogen in their renal tubules and shed pathogenic leptospires in their urine. Although many wild and domestic animals can serve as reservoir hosts , the brown rat (Rattus norvegicus) is the most important source of human infections. Individuals living in urban slum environments characterized by inadequate sanitation and poor housing are at high risk of rat exposure and leptospirosis. The global burden of leptospirosis is expected to rise with demographic shifts that favor increases in the number of urban poor in tropical regions subject to worsening storms and urban flooding due to climate change. Data emerging from prospective surveillance studies suggest that most human leptospiral infections in endemic areas are mild or asymptomatic. Development of more severe outcomes likely depends on three factors: epidemiological conditions, host susceptibility, and pathogen virulence (Fig. 1). Mortality increases with age, particularly in patients older than 60 years of age. High levels of bacteremia are associated with poor clinical outcomes and, based on animal model and in vitro studies, are related in part to poor recognition of leptospiral LPS by human TLR4. Patients with severe leptospirosis experience a cytokine storm characterized by high levels of IL-6, TNF-alpha, and IL-10. Patients with the HLA DQ6 allele are at higher risk of disease, suggesting a role for lymphocyte stimulation by a leptospiral superantigen. Leptospirosis typically presents as a nonspecific, acute febrile illness characterized by fever, myalgia, and headache and may be confused with other entities such as influenza and dengue fever. Newer diagnostic methods facilitate early diagnosis and antibiotic treatment. Patients progressing to multisystem organ failure have widespread hematogenous dissemination of pathogens. Nonoliguric (high output) renal dysfunction should be supported with fluids and electrolytes. When oliguric renal failure occurs, prompt initiation of dialysis can be life saving. Elevated bilirubin levels are due to hepatocellular damage and disruption of intercellular junctions between hepatocytes, resulting in leaking of bilirubin out of bile caniliculi. Hemorrhagic complications are common and are associated with coagulation abnormalities. Severe pulmonary hemorrhage syndrome due to extensive alveolar hemorrhage has a fatality rate of >50 %. Readers are referred to earlier, excellent summaries related to this subject (Adler and de la Pena-Moctezuma 2010; Bharti et al. 2003; Hartskeerl et al. 2011; Ko et al. 2009; Levett 2001; McBride et al. 2005).

721 citations