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Biomedical subjects

D E Govan

Publications and source records attributed to D E Govan.

At least 19 recordsLinked to original sources
PubMed1985

Conservative management of testicular endodermal sinus tumor in childhood.

Endodermal sinus tumor is the most common testicular neoplasm in childhood. The management of children with this neoplasm remains controversial. We have treated prospectively 5 children with stage I endodermal sinus tumor with limited surgery and no adjuvant therapy. The median patient age at diagnosis was 21 months (range 5 to 24 months). All children underwent an inguinal orchiectomy with high ligation of the spermatic cord. Retroperitoneal node dissection was not performed in any case and no child received adjuvant chemotherapy or radiation therapy. All patients were well without evidence of recurrent disease at a median followup of 46 months (range 19 to 72 months). Because these tumors usually are localized at the time of diagnosis, rarely spread to the retroperitoneal nodes and have a biological marker in most cases, and because good salvage chemotherapy is available for patients with relapse, we believe that nonmetastatic testicular endodermal sinus tumors in children can be managed with radical orchiectomy alone. Retroperitoneal node dissection is not necessary and adjuvant therapy is not indicated if markers return to normal. Further treatment should be reserved for the rare child with relapse.

Castration↗
PubMed1984

Isometric detrusor pressure during bladder filling and its dependency on bladder volume and interruption to flow in control subjects.

We characterized the isometric pressures generated by the bladder during voluntary detrusor contraction and interruption of flow. Urodynamic studies were done in 34 healthy female volunteers, with a mean age of 29.6 plus or minus 9.3 years. Control urodynamics were done first to characterize bladder and urethral parameters to filling and voiding. Subsequently, isometric detrusor pressures were elicited during bladder filling at increments of 100 ml. by asking subjects to attempt to void against a urethral obstruction produced by an inflated Foley balloon. Isometric pressures also were obtained by interruption of flow through the lumen of the 22F Foley catheter. The results showed that the maximum isometric pressure increase generated remained relatively constant during bladder filling at 39.6 plus or minus 13.1 cm. water. This pressure is not significantly different from voiding pressures developed with a 10F urethral catheter. On the other hand, isometric pressure increases during voiding showed that the increase in bladder pressure following interruption of flow was volume sensitive. The possibility that this volume dependency may result in errors in the interpretation of bladder contractility is discussed.

Adult↗
PubMed1982

Spatial distribution and timing of transmitted and reflexly generated urethral pressures in healthy women.

We localized the temporal and spatial distribution of pressures in the urethra to identify their contribution to continence. With the data obtained we resolved the timing between the passively transmitted and actively generated urethral pressures. Data were obtained from 11 healthy female volunteers, with a mean age of 22 years. Simultaneous measurements of bladder and urethral pressures were taken from subjects during the Valsalva maneuver and coughing, and then holding with the subject in the supine, standing and sitting positions. The ratio of urethral to bladder pressure increase and the latency between these pressure increases were analyzed. A biphasic pressure distribution results from coughing with subjects in all positions. The first phase occurs at the normalized distance of 10 to 15 per cent from the bladder neck, where the ratio of urethral to bladder pressure increase is 0.8. The second phase occurs at 60 to 70 per cent of the urethral length and has a 1.5 to 1.7 ratio of urethral to bladder pressure increase, indicating the presence of pressure magnification. Simultaneous latency measurements indicate that the pressure increase in the urethra precedes that of the bladder by 240 plus or minus 30 msec. in the region that exhibits maximum pressure magnification. These results indicate that a fast-acting contraction occurs in the distal third of the urethra, which contributes reflexly to the compressive forces of the proximal urethra, thereby preventing urine loss during stress.

Adolescent↗
PubMed1980

Urodynamic analysis of urethral, vesical and perivesical pressure distribution in the healthy female.

The transmission of intra-abdominal pressures to the urethra of the healthy female is examined with respect to cough, Valsalva and holding stimuli. A new method of recording urethral pressures using a four-channel, perfused gap catheter specifically constructed for this investigation is used. The results show that the increase of urethral pressure to stimuli is magnified at the distal urethra to a significant degree. This magnification is significantly higher than that expected by direct intra-abdominal transmission. Anatomically, the focus of urethral magnification of pressures is located 2-3 mm distal to the external urethral sphincter. The data provided from this study indicate that the mechanism of action of urethral closure to stress is active and does not directly correspond to the transmission properties of the lower urinary tract to stresses. Evidence supporting this mechanism is drawn also from the differential behavior of the proximal and distal regions of the urethra to the initiation and cessation of voiding.

Adolescent↗
PubMed1979

The effect of sympathectomy on the urethral pressure profile in the experimental animal.

The effect of sympathectomy and various pharmacologic agents on the dog urethral pressure profile (UPP) was assessed. Succinylcholine was used to subtract the effect of the external urethral sphincter from the total UPP. In the presence of succinylcholine effect, sympathectomy caused a decrease in the UPP in 12 of 13 experiments. In addition, an attempt was made to elicit a denervation sensitivity response to phenylephrine after sympathectomy; none could be shown. Measurements were made of UPP's after administration of both succinylcholine and phenylephrine. Seven of the 13 dogs showed a significant decrease in UPP after succinylcholine administration. Nine of 12 dogs showed a marked increase in UPP after phenylephrine was given.

Animals↗
PubMed1977

Posterior urethral valves.

During the past decade some urologists and radiologists have doubted the existence of posterior urethral valves. It has been suggested that the primary lesion in patients thought to have urethral valves is bladder neck obstruction. During the past seven years we have seen an average of three new cases of posterior urethral valves per annum. In all cases the valves themselves, not the bladder neck, obstructed the urethra. The urologist may miss valves at urethroscopy, but use of the new fibreoptic endoscope has improved his chances of seeing them. Posterior urethral valves may not be demonstrated radiologically if the radiologist does not use a rapid recording device or if the patient does not micturate forcefully during micturating cystourethrography. Failure to detect the valves may lead to an erroneous diagnosis of bladder neck obstruction.

Adolescent↗
PubMed1976

Influence of vesico-ureteral reflux on the response to treatment of urinary tract infections in female children.

3 groups of female children, comprising a total of 169 patients, were followed through successive episodes of urinary tract infection with respect to recurrence of infection. Group A consisted of 66 patients with no evidence of vesico-ureteral reflux. Group B comprised 42 patients with demonstrated vesico-ureteral reflux. The infections in these patients were treated with medical therapy alone and the reflux was not corrected. Group C consisted of 61 children who had surgical correction of vesico-ureteral reflux. While Groups B and C were not strictly comparable, the data indicate that there was no demonstrable difference in the rate of urinary tract infection among the 3 groups. Following short-term specific antibacterial therapy of a new infection, about 20% of children in each group were "cured", i.e., had no further infections during the 12 months or more that they were subsequently followed by the authors. Patients with less severe grades of reflux treated by medication alone (Group B) experienced no greater rate of reinfection than those children presenting with infections in the absence of vesico-ureteral reflux. In those children whose infections could not be adequately controlled by antimicrobial therapy, and those patients with severe (Grade III) reflux, surgery was performed to eliminate the vesico-ureteral reflux. The data also reinforced the concept that correction of reflux does not eliminate the need for constant vigilance and proper treatment of recurrent infections even after successful surgery has been carried out.

Child↗
PubMed1975

Management of children with urinary tract infections: the Stanford experience.

Two hundred seventy-eight female children with urinary tract infections have been evaluated at Stanford division of urology. All children were followed up for a period of not less than twelve months. Age of onset of infection, clinical presentation, and nature of infecting organisms were observed. The group consisted of 144 children without ureteral reflux and 134 children with ureteral reflux. Sixty-one of the female children with ureteral reflux had ureteral reimplantation, while 73 received medical treatment alone. A study of infection rates in each of the three groups of children indicated a similar infection rate, although those children with reflux experienced a higher incidence of clinical pyelonephritis. Correction of ureteral reflux did not alter the infection rate; however, infections after surgical correction were generally of a type usually associated with children without reflux. Twenty-nine children had urethral dilatation, and the infection rate prior to and following urethral dilatation indicated a similar rate of infection pre- and posturethral dilatation. One hundred nonrefluxing kidneys were observed radiologically: 97 were normal and 3 showed clubbing and scarring. Of 110 refluxing renal units observed, 62 were clubbed and scarred and 48 were normal. Following surgical correction of reflux, renal clubbing and scarring were not observed in previously normal renal units. Of those renal units found to be abnormal at time of surgery, 66 per cent showed progression of clubbing and scarring after surgical correction of reflux. It was observed that the greater the degree of reflux present, the higher the incidence of renal damage. This study suggests that children who experience recurrent urinary tract infections who do not have ureteral reflux are seldom at renal risk; similar children who do have ureteral reflux are at risk unless the infections are controlled or the reflux either disappears or is corrected surgically.

Anti-Infective Agents, Urinary↗
PubMed1974

Urinary tract infections in children. Part II--Roentgenologic aspects.

Roentgen findings in 107 girls under the age of ten years who had proven recurrent urinary tract infections were analyzed. From the excretory urograms done on these children, renal and pelvocalyceal outlines were accurately traced. Subsequently, renal length and parenchymal thickness at multiple points were measured. The presence or absence and grade of reflux were determined by voiding cystourethrography. Finally, the clinical history was correlated with the roentgen findings. With three exceptions, scarring and clubbing in the presence of infection occurred only in refluxing renal units. Kidneys exposed to a higher grade of reflux more frequently showed scarring and clubbing (p<0.001). Seventeen out of 40 renal units either developed or had increase in clubbing and scarring while the patients were being followed. After surgical correction of reflux, 16 of 24 previously clubbed and scarred kidneys showed progression of the lesions, usually within 24 months after operation. All children whose kidneys showed progression after surgical operation had experienced an episode of acute urinary infection with chills and fever before operation. No significant difference existed in the age at clinical onset of infection in patients with ureteral reflux with or without roentgen evidence of clubbing and scarring. This study documents the close relationship between clubbing and scarring and reflux in the presence of urinary infection in infants and children.

Age Factors↗