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Biomedical subjects

F D Stephens

Publications and source records attributed to F D Stephens.

At least 37 records · Page 2Linked to original sources
PubMed1983

Supernumerary kidney.

We studied 58 case reports of patients with supernumerary kidneys to determine the morphology, vagaries and embryogenesis of this rare and poorly documented anomaly. The supernumerary kidney usually was located caudal to the ipsilateral kidney when subserved by a bifid ureter and cranially when the ureters were separate. The Weigert-Meyer law for duplex fused kidneys was obeyed by the supernumerary ureter in most fully documented cases of double ureters. Pathologic conditions of the upper urinary tract occurred in more than 50 per cent of the patients with a bifid system, who were prone to have hydronephrosis and calculous disease, and with a double system, who were prone to have complications resulting from supernumerary ureteral ectopia. Double tails to the nephrogenic cords, each induced by a branch of a bifid bud or by 1 of 2 separate buds as opposed to tandem inductions of a single metanephros, were regarded as the probable embryogenesis.

Abnormalities, Multiple↗
PubMed1983

Cowper's syringocele: a classification of dilatations of Cowper's gland duct based upon clinical characteristics of 8 boys.

Lesions of Cowper's gland duct assume various appearances. A system to classify each of these appearances is offered to diagnose these lesions more precisely. The urethrographic and endoscopic characteristics of dilated Cowper's gland ducts noted in 8 boys are grouped as a simple classification. The dilated Cowper's duct is referred to as a syringocele (Greek syringo--tube plus cele--swelling). There are 4 groups of Cowper's syringoceles: 1) simple syringocele--a minimally dilated duct, 2) perforate syringocele--a bulbous duct that drains into the urethra via a patulous ostium and appears as a diverticulum, 3) imperforate syringocele--a bulbous duct that resembles a submucosal cyst and appears as a radiolucent mass, and 4) ruptured syringocele--the fragile membrane that remains in the urethra after a dilated duct ruptures. Marsupialization of the syringoceles cured urine infection and hematuria but voiding symptoms may persist.

Adolescent↗
PubMed1983

Cecoureterocele: morphology and clinical correlations.

A unique necropsy specimen of a cecoureterocele, together with the bladder and urethra in a female newborn, was studied to determine the structure of the ureterocele and the accompanying vesicourethral sphincter. The ureterocele within the bladder base and the entire urethra were examined macroscopically and microscopically in serial sections. The ureterocele and its cecal extension were amuscular. The bladder neck, and the involuntary and voluntary sphincters were attenuated or devoid of muscle in the quadrant beneath the ureterocele and its cecal extension. These findings were correlated with the clinical features of 2 living patients with comparable ureteroceles who had urinary incontinence following surgical excision of the ureteroceles.

Child, Preschool↗
PubMed1982

Ureterovascular hydronephrosis and the "aberrant" renal vessels.

The pelvis, an angulated upper segment of the ureter and the lower anterior renal segmental vessels entangle to produce hydronephrosis. However, which of the 3 structures provokes obstruction is conjectural. The structural relations in this anomaly were compared to those of normal kidneys, hydronephroses from other causes and nonrotated kidneys. This anomaly was unique in that the pelvis and ureteropelvic junction bulged over the lower hilar segmental vessels instead of under as in other forms of hydronephrosis. Transient or permanent defects of medial rotation of the renal pelvis may account for the vulnerability of the ureteropelvic junction to obstruction by the lower anterior segmental branch of the renal artery, which was not aberrant in all the examples studied.

Aged↗
PubMed1981

Morphogenesis of nephropathy with partial ureteral obstruction and vesicoureteral reflux.

Hydronephrotic kidneys associated with partial ureteral obstruction and vesicoureteral reflux are similar and should exhibit similar morphology if the hydronephrosis was caused by abnormal urodynamic effects or back pressure. Kidneys with partial obstruction were compared quantitatively and statistically to kidneys with reflux to identify the macroscopic and microscopic structures that would indicate similar or dissimilar etiologies of the hydronephrosis. With partial ureteral obstruction the kidneys exhibited a generalized paucity of parenchyma, occurring in the cortex and medulla, and increasing with the degrees of hydronephrosis. Kidneys with reflux, and mild and similar grades of hydronephrosis compared to those of the obstructive forms were indistinguishable microscopically. Kidneys with reflux and more severe grades of hydronephrosis were different in that the cortex and medulla exhibited hypoplasia combined with dysplasia and, although the cortex was approximately equal in thickness, the glomerular counts were smaller. These features in kidneys with reflux were proportional to the degree of lateral ectopia of the corresponding ureteral orifice. Obstructive atrophy of renal parenchyma explains the morphology of the obstructive hydronephrosis, whereas the hypoplasia and dysplasia corresponding with orifice position in the kidneys with reflux are explained more readily by the bud theory, in which the ureteral bud, metanephric mesenchyme and induction capabilities of each are all at fault. In the absence of infection the kidneys may undergo progressive atrophy with partial obstruction of the ureter, whereas the kidneys with reflux exhibit performed grades of hydronephropathy, which are determined embryologically.

Humans↗
PubMed1981

The pathogenesis of renal dysplasia. I. Quantification of hypoplasia and dysplasia.

In order to assess the relative effects of abnormal ureteric orifice position and abnormal urodynamics on the morphogenesis of hypoplasia and dysplasia in kidneys obtained from infants, we devised a method of quantifying the renal structures. The method was based on radial glomerular counts which ranged from zero to normal (seven to nine), a score for dysplastic structures, and the ratio of normal to abnormal tissues present. These three values, when plotted against each other, correlated closely. The glomerular count, with occasional minor adjustment for inconsistencies, was the best parameter of hypodysplasia. Severe to moderate grades of hypodysplasias fell in the low and middle ranges and hypoplasia through to normal in the highest range. By grading kidneys in this way, we were able to compare the effects of ureteral ectopy and abnormal urinary dynamics on the developing kidney.

Histological Techniques↗
PubMed1981

The pathogenesis of renal dysplasia. III. Complete and incomplete urinary obstruction.

We graded obstructed kidneys of infants on the hypodysplasia scale to assess the influence of complete and partial obstruction on the pathogenesis of hypodysplasia. Kidneys with complete obstruction exhibited severe grades; those with partial ureteral obstruction had near normal grades. Those kidneys subjected to partial urethral obstruction ranged from mild to severe grades which correlated with degrees of lateral ectopy of the urethral office. Renal parenchymal development was impaired by complete obstruction but was tolerant to incomplete obstruction. Abnormal orifice positions associated with urethral obstructions were considered to be manifestations of ectopic ureteric buds and the hypodysplasia to be evidence of abnormal induction of abnormal renal blastema.

Humans↗
PubMed1981

The pathogenesis of renal dysplasia. II. The significance of lateral and medial ectopy of the ureteric orifice.

Renal hypoplasia and dysplasia may be primary malformations linked to a panureteric bud deformity or result from damage to the developing nephrons caused by abnormal urodynamic pressures, Kidneys with misplaced ureteric orifices were graded, according to histologic criteria, on the hypodysplasia scale. With lateral ectopy of the ureteric orifices with and without congenital urethral obstruction, the grades correlated with specific orifice positions. The grades of kidneys with caudal ectopy of the ureters indicated a more general correlation. Dysgenesis of the bud and nephrogenic mesenchyme may account for the renal hypodysplasia when the ureteric orifice is found to be ectopic.

Female↗
PubMed1980

Dorsal urethral diverticulum of the fossa navicularis: symptoms, diagnosis and treatment.

Spotting of blood per urethram, hematuria and episodic painful voiding in boys are not uncommon symptoms, although often the causes are not known. The lacuna magna of the urethra on the glans penis can cause such symptoms, as is demonstrated in this report of 4 cases. Treatment was surgical, which resulted in the immediate cure and relief of symptoms. Our study indicates that radiography of the terminal urethra, probing and endoscopy of the fossa navicularis should be done regularly to determine whether the lacuna magna is the enigma of the symptom complex.

Child↗
PubMed1980

Valves of the ureter as a cause of primary obstruction of the ureter: anatomic, embryologic and clinical aspects.

The causes of obstruction of the ureter at the ureteropelvic and ureterovesical junctions are still controversial. In this study portions of obstructed ureters were excised at operation or autopsy and the suspected sites of obstruction were examined anatomically, radiographically and histologically. A valvular mechanism caused obstruction in 15 of 27 specimens. The valve lay at the junction of the dilated and undilated segments of the ureter. The internal anatomy of this site was hidden from external view by the fascia overlying the ureter and was demonstrated by contrast ureterograms. The axes of the lumina of the dilated and undilated segments were eccentric and the walls of the ureter overlapped at the site of obstruction to form a common wall, which created a valve effect. The valve flaps were visualized radiographically as a filling defect. The valve obstructed antegrade but not retrograde flow. Anatomic dissection or serial sections of blocks of the valve zone demonstrated that either a single or a double flap caused obstruction. The valve was coapted against the opposite wall of the distal segment by the pressure generated in the dilated ureter during antegrade flow. The muscle of the unobstructed segment of ureter distal to the valve appeared normal histologically, whereas the muscle of the obstructed proximal segment was hypertrophic.

Child↗
PubMed1979

The vesicoureteral hiatus and paraureteral diverticula.

Two ureteral sheaths and the vesical musculature combine to form a watertight ureterovesical junction but the precise anatomy and function of each component are still somewhat contentious. The morphology was studied in postmortem specimens of children with and without paraureteral diverticula and urethral obstruction, and function by deductive reasoning from radiographic and surgical observations in living children. Waldeyer's fascia (the superficial sheath) of the ureter was found to seal the potential space between the tunnel wall and the ureter, and deficiencies were associated with hiatal hernias. The deep sheath provided anchorage of the ureter to the trigone and through the attachments of the superficial sheath to the bladder wall. Both sheaths and the tunnel muscles could be identified clearly and dissected precisely at operations involving the ureterovesical junction to facilitate the surgical procedures.

Child↗
PubMed1979

The induction of urologic malformations. Understanding the relationship of renal ectopia and congenital scoliosis.

The normally straight caudal trunk of the 3-day-old chick embryo was surgically deflected, constricted, or pierced using fine steel instruments. The delayed effects of these injuries were evaluated anatomically by performing microdissections of the genitourinary systems of the chicks surviving these operations. Eighty-six of 181 survivors of 347 operations showed malformations. Renal ectopia appeared with scoliosis 10 times more often than it appeared by itself (P less than 0.01). Eighty-six chicks survived 102 control operations; only two had a urinary anomaly (P less than 0.01). The paring of renal ectopia with scoliosis may be attributable to an isolated spinal defect that precludes complete renal ascent, an injury to the anlages of both the spine and kidney, or a genetic abnormality that affects both anlages.

Abnormalities, Multiple↗
PubMed1978

The persisting mesonephric duct: high junction of vas deferens and ureter.

We describe 9 examples of a rare congenital anomaly in which the unduplicated ureter joined the vas and exhibited long persisting mesonephric ducts that resembled the ureter rather than the vas. Some of the kidneys were unexpectedly well developed. It is proposed that a cranial ectopic ureteral bud may have induced a metanephric kidney in the region of the mesonephros or the ectopic bud and the metanephric blastema were displaced cranially.

Abnormalities, Multiple↗