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Dive into the research topics where Thomas F. Kolon is active.

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Featured researches published by Thomas F. Kolon.


The Journal of Urology | 1996

THE IMPACT OF CO-MORBIDITY ON LIFE EXPECTANCY AMONG MEN WITH LOCALIZED PROSTATE CANCER

Peter C. Albertsen; Dennis G. Fryback; Barry E. Storer; Thomas F. Kolon; Judith Fine

PURPOSEnWe evaluated 3 indexes used to assess patient co-morbidities to determine whether they could predict mortality among men with clinically localized prostate cancer.nnnMATERIALS AND METHODSnWe measured the impact of co-morbidity classifications on all cause mortality using a parametric proportional hazards model based on a retrospective cohort analysis.nnnRESULTSnEach index tested is a highly significant predictor of mortality for patients dying of nonprostate cancer related causes after adjusting for age and Gleason score.nnnCONCLUSIONSnEach co-morbidity index provides significant, independent predictive information concerning patient mortality beyond that provided by age, Gleason score and clinical stage alone.


The Journal of Urology | 1999

A MULTICENTER OUTCOMES ANALYSIS OF PATIENTS WITH NEONATAL REFLUX PRESENTING WITH PRENATAL HYDRONEPHROSIS

C.D. Anthony Herndon; Patrick H. McKENNA; Thomas F. Kolon; Edmond T. Gonzales; Linda A. Barker; Steven G. Docimo

PURPOSEnApproximately 10 to 30% of prenatal cases of hydronephrosis result in the postnatal diagnosis of vesicoureteral reflux. Using a new generic prenatal-postnatal data sheet developed by the Society for Fetal Urology the characteristics, natural history and outcome of prenatal hydronephrosis confirmed postnatally to be vesicoureteral reflux were documented at 3 centers.nnnMATERIALS AND METHODSnWe performed a retrospective multicenter review of Society for Fetal Urology data sheets completed for each patient in whom prenatal hydronephrosis was proved to be postnatal vesicoureteral reflux from 1993 to 1998.nnnRESULTSnIn 56 male and 15 female patients with prenatal hydronephrosis a total of 116 refluxing renal units were confirmed postnatally. Of the 116 renal units 112 were hydronephrotic prenatally. During gestation increased hydronephrosis was noted with voiding in 4 cases. Of the 112 hydronephrotic renal units only 26 ureters in 15 patients were seen prenatally. The obstetrician considered the diagnosis of vesicoureteral reflux in only 24% of the cases. Postnatally 116 refluxing renal units were identified. Initial postnatal ultrasound was normal in 25% of the cases. Bilateral reflux was present in 36 male and 9 female patients. In 10 of the 19 uncircumcised patients (53%) urinary tract infection developed despite antibiotic prophylaxis. In 15 of the 74 renal units with grades III to V reflux the condition resolved at an average patient age of 0.9 and 2.1 years in boys and girls, respectively. A total of 27 refluxing renal units were reimplanted.nnnCONCLUSIONSnThe majority of prenatal reflux occurs in boys, and it is high grade and bilateral. The data sheets designed by the Society for Fetal Urology are useful data collection instruments. The presentation and natural history of vesicoureteral reflux are different in male and female individuals. In a significant number of renal units high grade reflux resolves spontaneously. Early circumcision may decrease the incidence of breakthrough urinary tract infection in this subpopulation. In addition, the effective management of prenatally detected reflux depends on multispecialty communication.


The Journal of Urology | 1999

Analysis of homeobox gene HOXA10 mutations in cryptorchidism.

Thomas F. Kolon; John S. Wiener; Michael Lewitton; David R. Roth; Edmond T. Gonzales; Dolores J. Lamb

PURPOSEnCryptorchidism is the most common congenital abnormality of the genitalia. However, its exact etiology remains to be defined. Homeobox (HOX) containing genes have a key role in the morphogenesis of segmental structures along the primary body axis, including the urogenital mesenchyma. In male mice with a targeted deletion of the HOXA10 gene cryptorchidism manifests in the absence of other major defects. Because to our knowledge this gene has never been examined for alterations in humans, we evaluated whether mutations of HOXA10 are associated with cryptorchidism in humans.nnnMATERIALS AND METHODSnGenomic deoxyribonucleic acid (DNA) was extracted from human blood or tissue samples from 16 noncryptorchid control subjects and 45 cryptorchid boys. To screen for mutations exons 1 and 2 of the HOXA10 gene were amplified individually by polymerase chain reaction using 6 overlapping oligonucleotide primer pairs. Single strand conformational polymorphism (SSCP) analysis of the amplified radiolabeled DNA fragments was performed. Variant band shifts were detected due to abnormal migration of the denatured DNA fragment compared to controls, suggesting an alteration in the DNA sequence. Sequence analysis of these variant bands was then done to define any mutations.nnnRESULTSnSSCP analysis revealed variants in 2 controls. Of the 45 samples from cryptorchid patients 30 had SSCP variants in exon 1. No variants were found in other regions of the gene. Sequence analysis revealed several DNA polymorphisms in exon 1 in controls and boys with cryptorchidism. Other nucleotide changes (point mutations) were noted only in exon 1 in the DNA of 5 cryptorchid patients, of whom 1 had a 24 nucleotide deletion.nnnCONCLUSIONSnOur initial analysis of the HOXA10 gene in humans demonstrates that genetic alterations of this gene may be present in some boys with cryptorchidism. HOXA10 polymorphisms exist in normal control subjects as well as in cryptorchid patients. Further analysis of the function of the mutated protein will elucidate the role of this gene as a potential causative factor of testicular descent.


The Journal of Urology | 2000

THE DORSAL INLAY GRAFT FOR HYPOSPADIAS REPAIR

Thomas F. Kolon; Edmond T. Gonzales

PURPOSEnHypospadias is a common genitourinary anomaly affecting every 1/300 male newborns. The goals of hypospadiac surgery include a straight penis with a urethral meatus at the tip of the glans, a well vascularized neourethra of adequate caliber with a solid, straight urinary stream and achievement of sexual function when mature. Current theory advocates preservation of the urethral plate with chordee correction. Hypospadias repair without an adequate urethral plate to roll into a tube requires longitudinal incision of the plate or a transverse preputial island flap. We describe a technique of 1-stage urethroplasty using an inner preputial based dorsal inlay graft.nnnMATERIALS AND METHODSnAfter the penis is degloved and chordee corrected incisions are made bilaterally along the urethral plate from the native urethral meatus to the glans tip. The urethral plate is incised longitudinally. A graft harvested from the inner prepuce is defatted and sutured onto the incised urethral plate. The neourethra is rolled into a tube in Thiersch-Duplay fashion.nnnRESULTSnThis technique was used in 32 patients. The original urethral meatus was coronal to penoscrotal and chordee release was performed concomitantly. At 21 months of followup no patient had a stricture, fistula or diverticulum at the inlay graft site.nnnCONCLUSIONSnThis technique successfully fulfills all traditional hypospadias repair criteria. We believe that the dorsal inlay graft after incision of the urethral plate is a rapid, easy and successful addition to the armamentarium of the hypospadiologist.


The Journal of Urology | 1998

Clinical and molecular analysis of XX sex reversed patients.

Thomas F. Kolon; Fernando Ferrer; Patrick H. McKENNA

PURPOSEnThe XX male syndrome presents with a spectrum of clinical appearances from phenotypic male individuals to true hermaphrodites. Previous reports established the sex determining region of the Y chromosome (SRY) gene as the testis determining factor. However, a subset of XX sex reversed male individuals exists without a translocation of SRY deoxyribonucleic acid (DNA) material to the X chromosome. In addition to clinical or endocrinological criteria, Y DNA probe studies, and radiological and surgical evaluation as indicated are necessary for an accurate diagnosis.nnnMATERIALS AND METHODSnWe evaluated 5 XX sex reversed patients (2 true hermaphrodites and 3 male individuals) by physical examination, pedigree analysis, endocrinological testing, molecular analysis of Y DNA, radiological studies and surgery (exploration and/or biopsy).nnnRESULTSnAll patients were SRY gene negative. Two patients were siblings. Complete endocrinological testing was negative in all cases. Two patients had a normal male phenotype. Radiological findings confirmed by cystoscopy or laparoscopy revealed a utricle, vesicoureteral reflux, and cervix and uterus in various patients. Gonadal biopsy showed ovotestes or ovary and testis in the 2 true hermaphrodites. The 3 XX male individuals had normal immature testes on biopsy.nnnCONCLUSIONSnCategories of XX sex reversal include classic XX male individuals with normal phenotypes, nonclassic XX male individuals with sexual ambiguity and XX true hermaphrodites. Simple translocation of the SRY gene to the X chromosome does not always account for testicular differentiation and a male phenotype. The masculinization of our patients in the absence of SRY suggests an alteration of 1 or more downstream Y, X or autosomal testis determining genes. We present another theory for male sex determination, including a downstream gene on the X chromosome in which expression is influenced by X inactivation. Y DNA genomic analysis, radiological studies and laparoscopic evaluation with gonadal biopsy as appropriate are recommended for complete assessment and treatment of these intersex patients.


The Journal of Urology | 2000

Upper urinary tract manifestations of the VACTERL association

Thomas F. Kolon; Christine L. Gray; Richard W. Sutherland; David R. Roth; Edmond T. Gonzales

PURPOSEnIn patients suspected to have the vertebral, anal, tracheoesophageal, renal, radial, cardiac and limb abnormalities (VACTERL) association we studied the frequency of upper urinary tract anomalies, prevalence of these features, predictability of upper tract pathology and proper screening evaluation.nnnMATERIALS AND METHODSnFrom 1991 to 1998 we identified 55 patients with the VACTERL association. Upper urinary tract assessment, including initial renal ultrasound and voiding cystourethrography, and followup data were available for 29 boys and 15 girls. Patients were considered to have the VACTERL association when 3 or more organ systems were involved.nnnRESULTSnAverage followup was 5.4 years. Upper urinary tract involvement was noted in 41 of the 44 patients (93.2%) and vesicoureteral reflux in 17 (25 renal units). Of the kidneys 21 were hydronephrotic without reflux or obstruction, 10 were solitary, 3 were multicystic dysplastic, 8 were obstructed and only 17 were normal. A total of 27 patients (61%) underwent at least 1 genitourinary procedure, primarily ureteroneocystotomy. All children were alive at the last followup.nnnCONCLUSIONSnThe VACTERL association involves multiple serious anomalies. However, these infants generally have a good outcome. Since the upper urinary system is the most common organ system involved, patients should receive prophylactic antibiotics until an initial urological assessment with renal ultrasound and voiding cystourethrography is performed. It is essential for physicians to know that most children with the VACTERL association have urological involvement that requires treatment and long-term management.


The Journal of Urology | 1997

Malignant Sertoli Cell Tumor in a Prepubescent Boy

Thomas F. Kolon; Howard I. Hochman

Sertoli cell tumor, also termed androblastoma or gonadal stromal tumor, is a rare testicular neoplasm. While it is usually benign, 25 cases of malignant Sertoli cell tumors have been reported. These neoplasms vary greatly in microscopic appearance and unfortunately they have aggressive metastatic behavior. Despite various treatments, the prognosis remains poor. We report on the fourth prepubescent boy with a malignant Sertoli cell tumor. CASE REPORT An 8-year-old white boy with insulin-dependent diabetes mellitus was found to have a hard, painless right testicular mass on a routine physical examination. There was no evidence of gynecomastia or precocious puberty. Ultrasound revealed an inhomogeneous, hyperechoic intratesticular region involving almost the whole right testicle. No serum elevations of a-fetoprotein or &human chorionic gonadotropin were detected. Right radical orchiectomy was performed. Grossly the testis had a thin rim of residual testicular parenchyma surrounding a solid, tan-yellow, lobulated 1.8 x 1 cm. tumor. No gross hemorrhage or necrosis was identified. Microscopically the tumor was encapsulated and coniined to the testicle. There was no invasion of the tunica albuginea, epididymis or spermatic cord. The tumor was composed of lobules, trabeculae and tubules of ovoid and polygonal cells with eosinophilic cytoplasm and moderate nuclear atypia. Central necrosis was present in many lobules and tumor cell mitoses were easily identifiable (see figure). Vascular invasion was not present. The uninvolved surrounding testicular parenchyma did not have intratubular germ cell neoplasia. Histological findings were characteristic of a low grade, malignant gonadal stromal (Sertoli cell) tumor. This diagnosis was confirmed by consultation with external referee pa


The Journal of Urology | 2001

COMPARISON OF SINGLE VERSUS MULTIPLE DOSE REGIMENS FOR THE HUMAN CHORIONIC GONADOTROPIN STIMULATORY TEST

Thomas F. Kolon; Oren F. Miller

PURPOSEnHuman chorionic gonadotropin (HCG) has a stimulatory effect on testicular steroidogenesis and has been widely used for evaluating male Leydig cell function. However, considerable variability exists in the protocols for HCG stimulation tests. In the most commonly used protocols HCG is administered daily for several days. We examine the circulating androgen response after 1 and 3-dose HCG regimens.nnnMATERIALS AND METHODSnWe evaluated 77 prepubertal boys diagnosed with hypospadias, cryptorchidism or micropenis. In 60 boys who underwent 1 dose of 100 IU/kg. or 5,000 IU/1.7 m.(2) HCG serum testosterone and dihydrotestosterone were sampled at 72 (28) and 96 (32) hours after injection, while in 17 who underwent 3 daily age adjusted doses hormone levels were determined on day 4. All blood specimens were obtained and injections were performed at 8:00 to 9:00 a.m. and all specimens were evaluated at the same endocrine reference laboratory.nnnRESULTSnNonstimulated testosterone levels were prepubertal in all groups. In the 1-dose groups post-stimulation testosterone was elevated 22 to 29-fold from baseline after a weight based and 34 to 35-fold after a body surface area based dose. Testosterone increased 20-fold baseline in the multi-dose group. No significant differences were observed in 72 versus 96-hour hormone levels.nnnCONCLUSIONSnEvaluating Leydig cell function by HCG stimulation is an important adjunct to the diagnosis of various urological conditions. A single weight or body surface area based HCG dose with androgen measurement after 3 or 4 days is a practical, reliable and cost saving change in testicular evaluation.


Fertility and Sterility | 1992

Custom cryopreservation of human semen

Thomas F. Kolon; Kimberley A. Philips; Jeffrey P. Buch

OBJECTIVEnTo design a protocol to evaluate individual variability in human semen cryoprotection by native seminal plasma.nnnDESIGNnPost-thaw motility from the frozen semen of pregnancy-proven donors (n = 10) and patients referred for infertility screening (n = 10) was examined in three equal aliquots (per original ejaculate) that comprised varying ratios of native seminal plasma to TES and Tris (TEST)-yolk buffer (Irvine Scientific, Irvine, CA) in a dose-titration curve format. All aliquots from the same ejaculate contained final vol/vol 6% glycerol, had equal sperm density, and had undergone centrifugation for 5 minutes at 600 x g before buffer:semen ratio adjustment and standard precooling protocol for submersion in liquid nitrogen. Post-thaw measurement of percent original motility preserved (post-thaw percent motility/original percent motility x 100) was used for standardization of results.nnnRESULTSnIn 14 of 20 specimens (70%), the maximal yield of original motility was obtained in 50% seminal plasma, with an average post-thaw motile yield of 50%. In 6 of 20 specimens (30%), the best preservation of original motility was noted at 100% seminal plasma, with an average post-thaw motile yield of 58%. No specimen had a greatest percent motility preserved at 0% seminal plasma. Donor specimens have equal preference for either 50% or 100% seminal plasma, whereas patient specimens have a preference for 50% seminal plasma (P < 0.05).nnnCONCLUSIONSnNative seminal plasma has variable cryoprotectant qualities for which custom cryopreservation can compensate. A simple two-point dose-titration test of cryopreservation buffer:seminal plasma ratio (i.e., 50:50 versus 0:100) can determine the optimal mixture for cryopreservation of a given individuals semen.


Urology | 2000

Hyperreninemia and congenital mesoblastic nephroma: case report and review of the literature

Oren F. Miller; Thomas F. Kolon

A 32-week estimated gestational age female infant had elevated systolic blood pressure at birth and a palpable left abdominal mass. Radiologic evaluation revealed a left upper pole renal mass. The renin level was significantly elevated. Left nephrectomy confirmed a diagnosis of congenital mesoblastic nephroma. The postoperative renin level normalized along with the blood pressure. Histologic analysis identified renin production from either the mesoblastic nephroma or secondarily from compression or ischemia. Mesoblastic nephroma should be considered as part of the differential diagnosis for hypertension in the young. The renin concentration and a renal ultrasound scan should be obtained as part of the evaluation.

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Barry E. Storer

Fred Hutchinson Cancer Research Center

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Christine L. Gray

Naval Medical Center San Diego

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David R. Roth

Baylor College of Medicine

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Dolores J. Lamb

Baylor College of Medicine

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Jeffrey P. Buch

University of Connecticut Health Center

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Peter C. Albertsen

University of Connecticut Health Center

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Dennis G. Fryback

University of Wisconsin-Madison

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