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Biomedical subjects

L R King

Publications and source records attributed to L R King.

At least 37 records · Page 2Linked to original sources
PubMed1995

Hydronephrosis. When is obstruction not obstruction?

It once was relatively simple for most urologists to diagnose ureteropelvic junction obstruction, and it was previously axiomatic that obstruction required repair to preserve and maximize renal function. Modern imaging studies have cast doubt on previously held concepts, leaving the clinician with an enigma. Prolonged follow-up of some non-operated cases has demonstrated late deterioration of function, further compounding the diagnostic uncertainty.

Child↗
PubMed1994

Kegel exercises and childhood incontinence: a new role for an old treatment.

Kegel exercises were used to treat urinary incontinence in 79 children. An average of less than 2 hours of professional time was required. Incontinence was eliminated in 60% of the patients; children who had both day and night wetting tended to show simultaneous improvements in both problems. Research is needed to test the hypothesis that Kegel exercises eliminate involuntary contractions of the detrusor muscle.

Adolescent↗
PubMed1994

Bladder mucosal grafts for severe hypospadias: a successful technique.

Free grafts of bladder mucosa may be used to bridge long urethral defects in the repair of hypospadias. Strictures, which occur commonly at the proximal anastomotic site with the native meatus and where the bladder mucosa is exposed on the glans, have limited the use of the procedure. We have found that draining the proximal anastomosis prevents most strictures. When the distal most portion of the neourethra is formed from the skin of the ventral penile shaft and glans, no bladder mucosa is exposed and meatal stricture is thereby avoided.

Follow-Up Studies↗
PubMed1994

Fertility after cryptorchidism: a comparative analysis of early orchidopexy with and without concomitant hormonal therapy in the young male rat.

Infertility is common in patients with a history of bilateral cryptorchidism, even after successful prepubertal orchidopexy. Recent data suggest that this defect may be partially due to the existence of hormonal abnormalities in some forms of cryptorchidism. To analyze any potential benefit of hormonal therapy, we have evaluated the immediate and long-term effects of chronic hormonal therapy administered following surgical correction of cryptorchidism. First, using young male rats, we examined the effects of chronic human chorionic gonadotropin (HCG) and a luteinizing hormone-releasing hormone agonist (LHRH-A), alone or combined, on acute pituitary-gonadal axis responsiveness to LHRH administration. High doses of HCG and/or LHRH-A induced deleterious effects on the pituitary-testicular axis in terms of suppression of response to LHRH. Therefore, treatment with a low dose of HCG (50 U/kg/day) for 14 days was used, since it produced a significant increase in intratesticular testosterone (ITT). Second, we tested this hormonal regimen in a cryptorchid rat model. Bilateral cryptorchidism was produced by gubernaculum resection at 14 days of age. Early orchidopexy was performed at age 30 days, and HCG therapy was given from 31 to 44 days of age. Follicle stimulating hormone (FSH), luteinizing hormone (LH) and testosterone (T) levels were determined before and immediately after hormonal therapy, and at sacrifice. Animals were sacrificed at 61 days of age for determination of serum and testicular hormone levels, accessory sex organ weights and testis histology. Five or six animals from each group were retained for breeding studies at the age of 90 days. Hormonal alterations noted immediately following treatment of cryptorchid animals with HCG are not lasting. The data reveal that the fertility defect in bilateral cryptorchidism is partially prevented by early orchidopexy and that adjunctive hormonal therapy is probably of little additional benefit.

Analysis of Variance↗
PubMed1994

Improved technique of laparoscopic nephrectomy for multicystic dysplastic kidney.

We report removal of a multicystic dysplastic kidney with a laparoscopic technique that uses only three trocar sites. Additionally, we have found placement of a ureteral catheter and full mechanical and antibacterial bowel cleansing unnecessary. The role of this surgery in the management of multicystic dysplastic kidney is discussed.

Child, Preschool↗
PubMed1993

Nonobstructive dilatation of upper urinary tract may later convert to obstruction.

We report on 5 babies found to have pyelocaliectasis or hydroureteronephrosis antenatally who were evaluated soon after birth because of persistent mild or moderate upper urinary tract dilatation. In each instance, vesicoureteral reflux was absent and the technetium-99m diethylenetriaminepentaacetic acid renal scan revealed good function in the ipsilateral kidney. Renogram curves, after furosemide, did not show an obstructed pattern. Indeed, allowing for the dilatation, the drainage patterns were thought to be normal. In each instance the patient represented or was found on follow-up to have increased dilatation. Renograms were then repeated, using the same radiopharmaceutical and dose of diuretic. An obstructive pattern was seen in each instance. These significant observations demonstrate that nonobstructive hydronephrosis, diagnosed prenatally, may later convert to obstruction at the ureteropelvic junction (UPJ) or in the juxtavesical ureter (UVJ). Thus, careful follow-up, for a period yet to be determined, is desirable in patients in whom the initial postnatal evaluation does not demonstrate obstruction by current criteria.

Constriction, Pathologic↗
PubMed1993

Valve of Guerin as a cause of dysuria and hematuria in young boys: presentation and difficulties in diagnosis.

A valve of Guerin, or lacuna magna, is a common anatomical finding in young boys. It occasionally causes dysuria and/or bloody urethral discharge or spotting due to its location distal to the external urethral sphincter. We report on 10 patients who underwent transmeatal marsupialization of a valve of Guerin between 1984 and 1991, and review the embryology and clinical presentation. Despite evidence suggesting that a valve of Guerin is a frequent, normal anatomical variant, the incidence of clinical detection is extremely low. While many patients with this condition remain totally asymptomatic, a valve of Guerin should be suspected in boys presenting with bleeding distal to the urethral sphincter with or without voiding symptoms. In most cases physical examination is normal. A carefully performed voiding cystourethrogram visualizing the distal urethra, coupled with endoscopic examination and gentle probing of the fossa navicularis, optimizes the likelihood of correct diagnosis. Treatment is indicated solely to ameliorate symptoms, which are probably caused by distention of the lacuna magna during voiding. Transmeatal incision and marsupialization of the valve leaflet into the urethral lumen usually effectively relieve dysuria and stop the bleeding.

Adolescent↗
PubMed1993

An experimental model of neonatal testicular torsion: evidence against an exclusively extravaginal etiology.

The present study was designed to determine whether extravaginal torsion of the spermatic cord (EVT) can be distinguished from intravaginal torsion (IVT) on the basis of gross and histologic examination of the testis. It is traditionally believed that EVT, postulated to occur only in neonates, can be grossly distinguished from IVT, which occurs in older patients, on the basis of adherence between testis and tunica vaginalis. Such adherence is felt to be present in EVT but not IVT. This concept that the two types of torsion can be distinguished in the operating room has important clinical ramifications. In cases of EVT, contralateral orchidopexy theoretically need not be performed, since adhesions develop between tunica vaginalis and dartos by a few weeks of age. This is in contrast to IVT, in which contralateral orchidopexy is necessary due to the bilateral nature of the bell clapper deformity. Using a rat model, we first demonstrated that IVT could produce adherence of the tunica vaginalis to testis. Then, eight rats were operated on, producing right IVT and left EVT. Animals were then sacrificed at intervals of up to one month. Gross and histologic examination showed involvement of the tunica vaginalis in an ischemic and inflammatory response in a majority of testes, regardless of the type of torsion. Attempts to distinguish EVT from IVT on the basis of grossly evident adhesions between tunica vaginalis and testis are of questionable validity. Early contralateral orchidopexy is therefore recommended in all cases of neonatal torsion.

Animals↗
PubMed1993

Usefulness of ovarian volume and cysts in female isosexual precocious puberty.

The real-time pelvic sonograms of 32 girls under 8 years old with true isosexual precocity (23 cases), pseudosexual precocity (four cases), premature adrenarche (four cases), and an undetermined problem (one case) were evaluated retrospectively for ovarian volume and presence and size of cysts. Sonographic findings were compared to those of 181 age-matched controls to determine the best sonographic indicator of precocious puberty. Ovarian volume was 4.6 cm3 in girls with true isosexual precocity, 4.1 cm3 in girls with pseudosexual precocity, and less than 1 cm3 in the other patients as well as in the control population. Ovarian enlargement was bilateral in true precocity and unilateral in pseudosexual precocity. Of the 181 subjects in the control group, 96 (53%) had ovarian cysts, almost all of which were small (less than 9 mm in diameter). Ovarian cysts occurred in 22 of 32 patients (69%) with precocity. The cysts generally were smaller than 9 mm in true isosexual precocity and larger than 9 mm in pseudosexual precocity. In conclusion, small ovarian cysts are not specific to precocious puberty and its various subtypes. Bilateral ovarian enlargement appears to be a reliable indicator of true isosexual puberty, whereas unilateral ovarian enlargement in combination with macrocysts is suggestive of pseudosexual precocity.

Anthropometry↗
PubMed1992

Method for correcting meatal stenosis after hypospadias repair.

Meatal stenosis is uncommon after hypospadias surgery even when the meatus is placed at the tip of the glans. However, when it occurs, such stenosis can be quite troublesome. A conventional meatotomy done in the presence of inflammation is often attended by recurrent stenosis. In such situations we therefore advocate placing a tourniquet around the base of the penis and raising a V-shaped flap of glans with the point of the V at the dorsum of the meatus. The stenosis is then incised along the back wall of the urethra down into non-inflamed tissues. The tip of the flap is sutured to this point and additional absorbable sutures are used to anchor the flap in place so that healthy tissue crosses the stenotic area. Recurrent stenosis after this maneuver is unusual.

Humans↗
PubMed1992

Effectiveness of a handsewn nipple valve for reflux prevention in bladder reconstruction.

The intussuscepted nipple has proved to be a versatile mechanism to provide continence or prevent reflux in urological reconstructive surgery. Early in its use detussusception of the nipple was recognized as a common complication, which was usually prevented by using several rows of staples to stabilize the nipple. The use of staples has reduced the rate of reoperation for eversion or obstruction but it has led to a higher stone formation rate, ranging from 10 to 18% in recent series. Since 1983 we have used a handsewn intussuscepted ileal nipple stabilized without staples as our antireflux mechanism in bladder augmentations and continent diversions. This technique has been performed in 30 patients with an average followup of greater than 3 years. A small bladder stone developed in only 1 (3%) of the patients, who was completely dependent on intermittent catheterization, while 4 (13%) required reoperation due to eversion of the nipple. This incidence compares well with nipple reoperation rates in recent series, which range from 7 to 28%. We conclude that absorbable sutures are as effective as staples in stabilizing the antireflux nipple, and that they result in a lower incidence of subsequent stone formation.

Child↗
PubMed1990

Staging of renal carcinoma using magnetic resonance imaging at 1.5 Tesla.

The preoperative magnetic resonance imaging (MRI) studies of 31 patients with surgically proven renal cell carcinomas obtained with a 1.5 Tesla unit were retrospectively reviewed to assess the accuracy of MRI for staging of tumor. According to the Robson classification 12 patients were found at surgery to have Stage I renal carcinoma, three patients had Stage II, ten had Stage IIIA, one had Stage IIIB, two had Stage IIIC, one had Stage IVA, and two had Stage IVB disease. Twenty-five (81%) of 31 patients were staged correctly by MRI. Clearly MRI showed venous tumor extension without the need for intravenous contrast administration. Also, MRI had a negative predictive value of 95%, and a positive predictive value of 100% for the evaluation of inferior vena cava tumor thrombus. At 1.5 Tesla MRI is an excellent staging modality in the preoperative evaluation of renal carcinoma. It is especially recommended in patients with equivocal computed tomography findings and in all patients with contraindications to the intravenous use of iodinated contrast material.

Adolescent↗
PubMed1990

Ectopia of the vas deferens.

Ectopic location of the vas deferens is a rare congenital abnormality that has a spectrum of presentations. Such cases have been associated with anorectal anomalies. Knowledge of distal Wolffian duct embryology may help to explain the developmental steps involved in these anomalies, as well as provide theories for the variations that may be encountered. Vas deferens development is reviewed, and two cases of vas ectopia are presented to illustrate and lend support to current theories of normal and abnormal vasal embryology.

Child, Preschool↗