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Biomedical subjects

F D Stephens

Publications and source records attributed to F D Stephens.

At least 55 records · Page 3Linked to original sources
PubMed1978

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↗
PubMed1977

"H-type" urethroanal fistula.

Stephens and Smith have recently described a urethroanal connection through which urine was passed preferentially into the otherwise normal rectum at the pectinate line. Other authors have reported similar deformities. The term "congenital 'H-type' anourethral fistula" was proposed for this rare anomaly by deVries and Friedland in 1974. In this communication, we describe two examples of the "H-type" urethroanal fistula (Fig. 1). Each patient also had tracheoesophageal fistula. One patient (R.P.), now 11 yr of age, has had successful correction of the anomaly. The other patient (T.McC.), a small premature baby whose uroanal deformity was investigated radiographically, died of sepsis and uremia. The anatomical relationships in this baby were investigated histologically in the autopsy specimen by means of serial sections. From this study, it has been possible to determine the sphincteric anatomy and to suggest a possible pathoembryology of the defect.

Child, Preschool↗
PubMed1977

Techniques and results of urodynamic evaluation of children.

Simultaneous recording of intravesical pressure, urine flow rate and anal sphincter electromyography was undertaken in 25 children with a variety of urological problems. Urethral pressure profile measurement was obtained in 3 of these patients and was used as an adjunct to cystometry alone in 5 others. The diagnostic patterns that emerged were useful in selecting specific pharmacologic and surgical therapeutic measures.

Adolescent↗
PubMed1977

Paraureteral diverticula. Associated renal morphology and embryogenesis.

A study was made of paraureteric diverticula, the associated ureteric orifices, and the accompanying kidneys. It was shown that the kidney was more abnormal as the ureteric orifice position lay more laterally and into the diverticulum. The fascial arrangements of the terminal ureter and the related diverticulum were examined. When the ureter opened totally within the diverticulum, both structures showed a single investment of fascia, suggesting a common embryologic orgin of the two structures. When the ureter opened either separately into the bladder or on the verge of the diverticulum, the urter and the adjacent diverticulum each had separate fascial investment, suggesting a different etiology for the formation of this type of diverticulum. A total of 25 single-system specimens were employed for the above study. In the series there were an additional three duplex systems associated with paraureteric diverticula in shich the kidney morphology followed the above pattern but the fascial arrangements were different. Based on the observations of this investigation, it is suggested that the renal morphology is governed by the position of the ureteric orifice in the diverticulum and that the term vesical hiatal diverticula be used to denote those diverticula occurring in the vicinity of the ureteric orifice. It is further suggested that the diverticulum which engulfs the ureteric orifice be called paraureteral, and those with separate orifices in the bladder be termed periureteral to differentiate the embryologic from the pulsion etiologies.

Autopsy↗
PubMed1977

Fused kidneys: morphologic study and theory of embryogenesis.

A study was made of 50 fused kidneys; 41 postmortem specimens and 9 living patients' records were reviewed. Three patterns of renal fusion were identified--midline fused horseshoe kidney [15], laterally fused horseshoe kidney [21], and crossed renal ectopia [14]. These morphologic renal patterns were correlated with coexisting abnormalities of the urinary tract and other organ systems. A high incidence of hydronephrosis of varied etiology, vertebral, and anorectal defects was found in the laterally fused horseshoe and crossed renal ectopic groups. A theory of embryogenesis was developed to explain the asymmetric patterns of renal fusion exemplified by laterally fused and crossed fused kidneys. It was based on the effects that the lateral flexion and rotation of the hind end in the 4- to 5-mm embryo exert on the relative positions of the nephrogenic cords and wolffian ducts.

Child↗
PubMed1977

Ureteral muscle tone in prevention of vesicoureteral reflux.

Three experiments were devised to examine three aspects of the mechanism of the ureterovesical valve in dogs: muscle defects, orientation of muscle in the submucosal segment of the ureter, and the support afforded by the firm bladder base. The ureterovesical valve mechanism of the dog was found to be inefficient when the roof of the submucosal segment was denuded in situ of its muscle. The valve remained efficient when the extravesical ureter, with its circular and oblique arrangement of muscle, was substituted for the normal submucosal ureter with its longitudinally disposed muscle. The efficiency of the ureterovescial junction was not impaired by substituting a floating bed of bladder muscle for the firm platform of the bladder base in which it is normally embedded. The bladder muscle of the hiatus was not effective in the prevention of vesicoureteral reflux if the submucosal segment was rendered inefficient as a sphincter by excision of the muscle in its roof or by excision of the segment. Muscle in the submucosal segment, arranged in either longitudinal or circular fashion, was an effective activator of the mechanical valve. Presumably, the tonic action of the smooth muscle is the activator that ensures the efficiency of the one-way flow flap-trap regulator of the ureterovesical junction.

Animals↗
PubMed1976

The natural history of reflux and long-term effects of reflux on the kidney.

Spontaneous cessation of vesicoureteral reflux occurred in 42 per cent of 102 patients. It ceased in 65 per cent of the patients with unilateral reflux, in 50 per cent of those with bilateral reflux in normal caliber ureters and in 9 per cent of those with bilateral dilated ureters. Renal parenchymal changes were seen most frequently in patients with urinary infection after diagnosis. The likelihood of such infections lessened if reflux ceased. Proportionately more male than female subjects were free of infection. Renal damage may follow even 1 episode of infection. Lesions appeared with equal frequency during the entire followup period, whereas urinary infection was more common in the 5-year period after diagnosis. Renal damage was more likely to occur in kidneys that were already abnormal. Reflux should be controlled surgically if urinary infections occur after diagnosis and during long-term chemotherapy and careful observation. In the absence of infection indications for operation are infrequent. Non-surgical management may apply to normal caliber ureters and in infancy, while antireflux operation may be considered at diagnosis in dilated ureters, bilateral reflux or in the presence of renal lesions.

Adolescent↗
PubMed1976

Correlation of ureteral orifice position with renal morphology.

Double ureters and kidneys have provided models for the comparison of radiographic appearances and the microstructure of each renal segment, as well as the correlation with the position of the corresponding ureteral orifice. An orifice located within the limits of the normal vesical trigone portends normal renal radiography and morphology. Orifices outside the normal limits of the trigone signify accompanying renal malformations in the corresponding kidneys, such as hypoplasia or aplasia of nephrons that are often difficult to determine histologically but that give rise to thin kidneys and clubbed calices, dysplasia of nephrons and abnormal interstitial tissue and blood vessels, all of which are detected more readily on microscopic examination. The more abnormal the orifice is in location and characteristics the more abnormal are the ureteral and renal segments. The correlation also applies to upper tracts when they are associated with lower tract anomalies, such as congenital urethral valves, neuropathic bladders of myelomeningocele patients and paraureteral diverticula.

Humans↗
PubMed1976

Primary rectal ectasia. A quantitative study of smooth muscle cells in normal and hypertrophied human bowel.

The quantitative study showed that, in the normal human colon, smooth muscle cells increased both in size and in number in the first three years of life. Then the cell size remained relatively constant, having an anverage value of 4,260 cubic microns, while the cell number increased further with age. In the secondary megacolon in children with Hirschsprung's disease, both hypertrophy and hyperplasia of smooth muscle cells were found as a response to the obstruction. Release of obstruction by a defunctioning colostomy was followed by a reduction in size of the hypertrophied smooth muscle cells, but the increased cell number persisted for more than three months. The specimens of megarectum and megasigmoid colon associated with congenital rectal fistulae were different in their muscle cell dimensions according to the age after birth when the quantitation was undertaken. When examined weeks or months after birth, the walls of the enlarged viscus were thick, the muscle cells were hypertrophic and the numbers were greater than normal. Faecal masses, when present in the defunctioned obstructed bowel, probably induce hypertrophy and hyperplasia of muscle cells. When, however, the specimens of the large rectosigmoid confluence were obtained for quantitation within a few hours after birth, they were found to exhibit localized expansions with abrupt change to nearly normal calibre, the dilated bowel being thin-walled and containing muscle cells in normal or smaller than normal size and numbers. It is probable that some of those obtained later were at birth similar in their muscle cell dimensions to those examined at birth, but that hypertrophy and hyperplasia had developed secondarily. The muscle cell dimensions of the viscus at birth indicates that the enlargement was not caused by the stimulus of increased work load prior to birth. Those enlargements present at birth are presumably developmental aberrations of expansion or overgrowth of the cloaca when the vesical component is also enlarged, or of its posterior component when the rectum alone is enlarged. When the rectum is abnormally large at birth and is subsequently used in reconstructive surgery of the associated anorectal deformities, it may lead to a large "terminal reservoir" with overflow incontinence which does not respond to aperient or bowel washout treatment. If recognized on the newborn pre and post colostomy radiography, reconstruction should include excision or perhaps trimming, of the dilated segment. The term primary rectal ectasia was recommended as the connotation for this special entity as distinct from megarectum developing to secondary obstruction.

Anal Canal↗
PubMed1976

The association and embryogenesis of tracheo-oesophageal and anorectal anomalies.

Thirty-one patients with combined oesophageal and anorectal anomalies were studied. They comprised 10% of 328 consecutive foregut malformations and 246 anorectal deformities. Twenty-three of this series also exhibited at least 3 of the VATER defects. There was a very high incidence particularly of associated vertebral, urological and musculoskeletal anomalies. This high incidence of addditional lesions is presumably a reflection of generalized early damage to the mesenchymal tissues at the fourth week of gestation. Similar embryological mechanisms may take place and be affected similarly in both foregut and hindgut systems. The concept of a two-component septum dividing the foregut and hindgut is proposed to explain the formation and malformations in these regions. Disturbances of alignment, direction and extent of these component septa induced by hyperflexion of the foregut and hindgut, and intrinsic septal defects presumably account for most of the malformations. Hyperflexion may also account for malformations of other systems and for the high incidence of associated anomalies in the 31 patients with oesophagorectal deformities.

Abnormalities, Multiple↗
PubMed1975

Duplex kidneys: a correlation of renal dysplasia with position of the ureteral orifice.

A study was made of 51 duplex kidneys, ureters and bladders to assess the types of abnormalities seen in duplex kidneys. The abnormalities affected ectopic and orthotopic segments equally. The occurrence of renal abnormality was closely correlated to the abnormal locations of the segment's ureteral orifice. When the orifice was displaced either cranially (orifice positions B, C and D) or caudally (orifices G and H) the orthotopic and ectopic segments, respectively, showed more severe hypoplasia and dysplasia. Faulty embryogenesis is proposed to explain these findings and the importance of endoscopic positioning of the ureteral orifice is emphasized in determining whether heminephrectomy will be necessary.

Child↗
PubMed1975

The response of smooth muscle cells in the rabbit urinary bladder to outflow obstruction.

The morphologic response of smooth muscle cells in the urinary bladder to a standardized bladder neck obstruction and the cell changes subsequent to release of that obstruction were studied in both growing and adult rabbits. The bladder reacted first by gross dilation and then by concentric thickening of the wall at the expense of the lumen. Microscopically, thickening of the bladder wall was due to temporary submucosal edema, then to the increased fibrocollagenous connective tissue, and finally to the increased muscle mass which in part replaced the connective tissue. Hypertrophy of the smooth muscle cells and their nuclei was apparent and this preceded cellular hyperplasia, which did not occur until 30 days after the obstruction was induced in the adult rabbits. In contrast, there was early hyperplasia of smooth muscle cells in the growing rabbits, followed by hypertrophy of the cells and their nuclei. In no instance could mitosis of smooth muscle cells be found in either young or adult rabbits. Quantitation showed that the degree of cellular hypertrophy was proportional to the duration of the obstruction. In the adult animal, the muscular thickening was mainly due to an initial 5 fold increase of the muscle cell volume together with a later 3 fold increase of muscle cell number. In the growing rabbits, the muscle cells first doubled in number and then after 8 weeks a 6 fold enlargement of cell volume contributed to the total muscular thickening. Upon release of obstruction in the adult rabbits, both enlarged cell and nuclear sizes regressed to normal values and the cell numbers gradually decreased to near normal values over periods up to 4 months after release.

Animals↗
PubMed1975

A quantitative study of smooth muscle cells in reflux, obstructed, and triad bladders. A preliminary report;.

This quantitative study has shown that the average size of the vesical smooth muscle cells of humans increases with age, whereas the average nuclear size remains constant. In the bladders of six babies with proven outflow obstruction, the cell size was signigicantly increased. In 23 of 25 bladders of infants and children with vesicoureteral reflux there was no apparent hypertrophy, but in two the cells were larger than normal and the micturition cystourethrograms exhibited features which may signify impairment of outflow. In two autopsy bladder specimens of two newborn, triad syndrome babies, there was no hypertrophy of muscle cells, indicating absence of obstruction in fetal life. Three giant bladders associated with rectovesical fistula deformities (two newborn specimens) and dyskinesia of the small and large bowel showed no hypertrophy of muscle cells, indicating that the enlargement was unlikely to be obstructive and appeared to be developmental in origin. Hypertrophy of muscle cells of the bladder indicated obstruction to the outflow, even when the degree of obstruction was mild. Muscle cell size can be measured on full thickness small surgical biopsy specimens prepared as paraffin sections and hence the method can be useful in clinical practice.

Adolescent↗