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Biomedical subjects

H W Johnson

Publications and source records attributed to H W Johnson.

At least 37 records · Page 2Linked to original sources
PubMed1989

Wilms tumorlet, nodular renal blastema and multicystic renal dysplasia.

We reviewed 60 cases of multicystic renal dysplasia collected during a 10-year period. Differentiated nonproliferative nodular renal blastema occurred in 6.7 per cent of the cases, which is similar to the incidence of nodular renal blastema in kidneys of other infants with congenital obstructive uropathy. A unique case of cystic dysplasia containing nodular renal blastema and Wilms tumorlet indicates the possibility that a persistently proliferative nephroblastomatous lesion may rarely occur.

Child↗
PubMed1989

Undiversion in patients with meningomyelocele.

Since 1981, 12 patients with neurogenic bladder due to meningomyelocele who had had previous ileal conduit urinary diversions underwent assessment for undiversion. Two important criteria for undiversion were motivation and a reconstructable bladder. Four patients either did not fulfil these criteria or refused surgery. Eight patients (six females and two males) underwent undiversions. Uretero-ureteral anastomosis was achieved in 13 ureters and ureteroneocystostomy in 2; transureteroureterostomy was necessary in 1 ureter. Augmentation cystoplasty and vesicourethropexy were important in establishing continence postoperatively; these procedures were not performed in two patients whose undiversion failed early in the series. The evolution of an investigation protocol, surgical technique and final approach to this complex problem are discussed.

Anastomosis, Surgical↗
PubMed1988

Testicular adhesion: a potential complication from wedge testicular biopsy in childhood leukemia.

Elective bilateral wedge testicular biopsy is frequently performed in childhood acute lymphoblastic leukemia. Acute and delayed complications of this procedure are rarely encountered. We report on two children with testicular adhesions 16 and 20 months postsurgery. In each instance there were resultant diagnostic and management difficulties. The possible cause and potential side effects of testicular adhesions are discussed.

Adhesiveness↗
PubMed1988

Dicentric Y chromosome and mixed dysgenesis.

We report 4 cases of mixed gonadal dysgenesis with a karyotype containing a dicentric Y chromosome. All cases were mosaic with 45X and 46X, dic(Y) cell lines. Of the patients 1 had ambiguous genitalia and some features of Turner's syndrome, 2 had classical features of Turner's syndrome with normal female external genitalia and 1 had no features of Turner's syndrome but he presented with penoscrotal hypospadias, inguinal hernia and cryptorchidism. Female gender assignment and early total gonadectomy should be considered when a dicentric Y chromosome is present in cases of mixed gonadal dysgenesis.

Child, Preschool↗
PubMed1988

Bladder-outlet reconstruction in neurogenic bladder due to myelomeningocele.

In a subgroup of children with myelomeningocele, urinary incontinence cannot be managed by clean intermittent catheterization and anticholinergic medication. The authors report on 24 such children who required bladder-outlet reconstruction. Twelve boys underwent the Young-Dees/Leadbetter procedure, 8 girls underwent the Burch procedure and the remaining 4 had a combination of the two. Augmentation cystoplasty was also carried out in seven girls and one boy. Results were most favourable in the girls, with improvement in 92%, in contrast to the boys in whom only 58% were improved. Artificial sphincter placement may be a more beneficial alternative for boys.

Adolescent↗
PubMed1987

Neonatal renomegaly.

A retrospective clinical review was done to study the value of ultrasound and renography in the investigation of 100 neonates with renomegaly. Abnormalities in 73 patients were detected antenatally with ultrasonography. Of the neonates 47 had lower urinary tract pathological conditions and ultrasound was more than 90 per cent accurate in identifying the accompanying ureteral dilatation. A total of 53 neonates had upper tract anomalies (ureteropelvic junction obstruction or cystic dysplasia). With ultrasonography the degree of pyelocaliectasis in patients with ureteropelvic junction obstruction was classified as mild (22 units), moderate (13) or severe (7). Initial treatment and followup were reviewed to study the clinical course of neonates with mild to moderate degrees of pyelocaliectasis followed nonoperatively, and to determine whether the diuretic renogram had a predictive role in identifying which kidneys were most likely to deteriorate.

Dilatation, Pathologic↗
PubMed1986

Stability of Liposyn II fat emulsion in total nutrient admixtures.

Compatibility and safety of a safflower oil-soybean oil lipid emulsion (Liposyn II, Abbott) with amino acids and dextrose in total nutrient admixtures (TNAs) were studied. Sixty-two admixtures representing 31 different combinations of fat emulsion, amino acid injection, and dextrose injection were tested. Both 10% and 20% concentrations of the fat emulsion and three concentrations each of amino acid injection and dextrose injection were used; the core admixture components were placed in empty flexible plastic bags in three different sequences: fat, amino acids, dextrose; fat, then dextrose and amino acids simultaneously; and amino acids and dextrose simultaneously, then fat. One of two mixtures of electrolytes and trace metals was added to each sample at the end of mixing. Six samples were tested after one day at 25 degrees C, 35 after two days at 5 degrees C plus one day at 30 degrees C, and 21 after nine days at 5 degrees C plus one day at 25 degrees C. Multivitamin injections were added to each TNA just before the 24-hour room-temperature storage. pH, emulsion particle size, and zeta potential (electrostatic surface charge of lipid particles) were measured after visual inspection of each sample. Amino acids were separated by high-performance liquid chromatography and measured. Dextrose was measured by size-exclusion chromatography. In a controlled study of 24 dogs, six-hour infusions of TNAs containing Liposyn II 20% were administered for 14 days, after which all major organs and tissues were studied microscopically. At all storage times in the compatibility study, all TNAs retained a uniform, milk-like appearance.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1985

Megalourethra.

We present 5 examples of megalourethra. All 5 cases were associated with the spectrum of the triad syndrome, ranging from minor hydronephrosis and undescended testis to gross hydronephrosis incompatible with survival. Initial management of this urethral defect is drainage followed later by reconstruction.

Child, Preschool↗
PubMed1984

Microdissection and radiographic studies of the arterial vasculature of the human testes.

Conflicting and sparsely detailed reports concerning the arterial vasculature of the testes prompted us to study 51 human cadaveric testicles radiographically in order to document any interarterial communications. Twelve specimens were harvested from the pediatric age group and 39 from adult cadavers. Vascular communication was demonstrated between the testicular, cremasteric, and vasal arteries in all specimens studied. Large-caliber anastomotic channels were demonstrated between the testicular and vasal arteries in 87% of specimens. No discernible differences in these vascular communications were documented among adult, pediatric, and undescended testes.

Adult↗
PubMed1983

Patch autografts in the treatment of urethral stricture.

Single-stage skin patch urethroplasty has become accepted therapy for urethral stricture. Review of the literature and the authors' experience indicated good short-term clinical results (80%), but the fate of the implanted tissue has not been well documented. Twenty-three skin and vein patch autograft repairs of defects created in the rabbit urethra were examined histologically after 4 weeks in situ. Two of 12 skin grafts remained intact while 9 of 11 vein patches were successful. The vein patch autograft appears to provide better support because of the survival of the elastic and smooth muscle tissues. Unlike skin grafts, which retain their squamous epithelium, the venous endothelium is entirely replaced by urothelium, thus decreasing potential neoplastic degeneration, and the incidence of fistula formation, fibrosis and chronic inflammation. Further investigation is required before introducing the vein patch urethroplasty into clinical practice.

Animals↗
PubMed1982

The development of microsurgical techniques in experimental and clinical repair of urethrocutaneous fistulas.

We reviewed 60 urethral fistulas in 50 patients seen between 1974 and 1979. After the results of this study were assessed technical aspects of the repair were incriminated to account for the 40 per cent failure rate for first-time closure of urethral fistulas in our area. To study this problem an animal model was created in the laboratory. A comparison was made between classically repaired fistulas and those repaired with microsurgical equipment and techniques. In the group repaired by a classical macrosurgical technique only 20 per cent of the repairs were successful, while 90 per cent of the repairs under the microscope succeeded. Techniques and material, as well as histology involved, are presented in detail. Some of the causes of fistula repair breakdown clarified in this study include tissue trauma "para fistula" fistulas due to needle trauma and nonrecognition of multiple small additional fistulas. Details of 25 fistulas in 19 patients in whom closures were done with microsurgical techniques are presented. Success rate for primary closure was 88 per cent.

Animals↗
PubMed1981

Comparison of microscopic and macroscopic repair in rabbit urethral fistulae.

Two fistulae were created in each of 26 adult male New Zealand rabbits. In six, no closure was carried out. In 20 rabbits subsequent closure was carried out using, alternately, a macroscopic and microscopic technique. We were then able to evaluate a total of 26 repaired fistulae using several parameters. Patency of the fistulae was present after 3 months in all six rabbits in which no closure was carried out. Comparison of the two techniques showed nine recurrences or persistent fistulae in the ten repaired by standard macroscopic techniques, and one fistulae still present after closure of 16 fistulae using microsurgical principles. This preliminary study emphasizes the potential improvement in urethral fistula repair using the operating microscope. Direct transfer into the clinical setting is underway with the use of techniques used in the Microsurgical Laboratory at the University of British Columbia.

Animals↗