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Biomedical subjects

R Gonzalez

Publications and source records attributed to R Gonzalez.

At least 253 records · Page 14Linked to original sources
PubMed1989

Compatibility of enterocystoplasty and the artificial urinary sphincter.

Placement of the artificial urinary sphincter during augmentation enterocystoplasty may lead to infection, erosion and eventual removal of the device. To assess compatibility of artificial urinary sphincter implantation and enterocystoplasty we reviewed the records of 30 patients who had undergone enterocystoplasty and artificial urinary sphincter placement simultaneously (11), enterocystoplasty before artificial urinary sphincter placement (12) and artificial urinary sphincter placement before enterocystoplasty (7). The 19 male and 11 female patients were between 4 and 42 years old (median age 13.5 years). Followup in 28 patients ranged from 6 months to 8 years (average 17 months). Incontinence resulted from myelodysplasia in 16 patients, sacral agenesis in 3, spinal cord injury in 6, posterior urethral valves in 1, bilateral ectopic ureters in 1 and epispadias-exstrophy in 3. Erosion occurred in 2 patients (7 per cent): 1 female patient who underwent simultaneous sphincter implantation and enterocystoplasty and who had undergone previously many bladder neck reconstructive procedures, including polytetrafluoroethylene (Teflon) injection, and 1 female patient in whom the augmented bladder was entered at artificial urinary sphincter implantation. Mechanical failure occurred 4 times in 3 patients and the artificial urinary sphincter was improperly placed in 1. Over-all continence rate was 87 per cent (26 of 30 patients). Simultaneous placement of the artificial urinary sphincter and enterocystoplasty did not seem to affect the outcome of sphincter implantation if good bowel preparation, intravenous antibiotics and sterility of urine were accomplished preoperatively. Entering the augmented bladder during sphincter implantation may predispose to infection and erosion.

Adolescent↗
PubMed1989

The artificial sphincter AS800 in congenital urinary incontinence.

The artificial urinary sphincter AS800 was implanted in 33 male and 13 female patients with congenital urinary tract incontinence. In 15 patients (32 per cent) previous operations to correct incontinence had failed. The sphincter was implanted around the bladder neck in 43 patients and around the bulbous urethra in 3. Mean patient age at the time of sphincter implantation was 13 years. In 40 patients (87 per cent) the sphincter functions well after a mean followup of 25 months and 39 patients (85 per cent) have satisfactory continence. In 6 patients the sphincter was removed because urethral, vulvar or scrotal erosions developed, all of whom had had previous surgical procedures in the area of the erosion. In 1 patient not operated upon previously erosion of the bulbous urethra developed. He did well after a new sphincter was implanted around the bladder neck. Five patients required an enterocystoplasty to achieve continence following the sphincter implantation. Nine patients required surgical revision of the sphincter for mechanical failure, technical errors, trauma and patient growth. We conclude that in patients with neurogenic sphincter failure implantation of an artificial sphincter around the bladder neck should be considered as the initial treatment of choice.

Adolescent↗
PubMed1989

Nonintubated Anderson-Hynes repair of ureteropelvic junction obstruction in 60 patients.

We reviewed our experience with 68 consecutive Anderson-Hynes ureteropyeloplasties. The 64 infants, children and young adults ranged from 2 days to 28 years old (median age 2 years), and 28 were less than 1 year old. Intubation was used in only 4 patients: 2 who also underwent ureteral reimplantation for vesicoureteral reflux, 1 with stones in the renal pelvis and 1 with pyonephrosis. We successfully repaired 60 of 64 nonintubated renal units (93.4 per cent). Temporary postoperative ureteral stenting was required for extravasation from 8 renal units (12.5 per cent). Two patients later underwent repeat ureteropyeloplasty for recurrent obstruction. Nephrectomy was performed for pyonephrosis in 1 patient and for a nonfunctioning kidney that had exhibited poor function preoperatively in 1. Prolonged ileus necessitated extended hospitalization in 3 patients (4.6 per cent). We conclude that nonintubated dismembered ureteropyeloplasty for uncomplicated, primary ureteropelvic junction obstruction can be performed safely and successfully, and should be considered the standard treatment. Positioning of the Penrose drain is critical to avoid urinoma formation. When persistent urinary leakage occurs temporary diversion is easy and well tolerated. Hospital stay averaged 12.1 days for patients with extravasation compared to 4.3 days when no extravasation occurred. Immediate preoperative retrograde pyelography did not seem to contribute to postoperative urinary extravasation by causing edema of the ureteral orifice.

Adolescent↗
PubMed1989

Urethral false passage as a complication of intermittent catheterization.

Intermittent catheterization is used commonly to treat bladder dysfunction. We treated 10 patients who were experiencing difficulty with intermittent catheterization, 9 of whom had a false urethral passage. Of these patients 6 had previously undergone a bladder neck or urethral operation. Endoscopy was helpful to diagnose the condition. Treatment consisted of stenting in 3 patients, transurethral incision and stenting in 3, and fulguration and stenting in 4. An indwelling catheter was left in place for 2 to 3 weeks, after which intermittent catheterization was resumed with a softer catheter. Two patients again experienced severe difficulty with catheterization and they underwent a continent urinary diversion. When intermittent catheterization becomes difficult or impossible, the presence of a urethral false passage should be suspected as a possible cause.

Adolescent↗
PubMed1989

Modified Benchekroun technique for continent ileal stoma.

The Guzman continent ileal stoma is constructed by a modification of the Benchekroun technique, which is based on the principle of the inkwell and collapse of the inner tube through retrograde filling of the valve. We used this procedure in 7 patients, all of whom are continent. During a followup of 6 months to 2 years no major complications developed. The stoma is easy to construct, has a low risk of evagination because the inner tube is stabilized with sutures and is easy to catheterize. It does not require staples, which reduces the chance of stone or fistula formation. The terminal ileum in continuity with the cecum or an isolated ileal segment can be used.

Follow-Up Studies↗
PubMed1989

The outcome of renal transplantation in children with the prune belly syndrome.

Children with the prune belly syndrome are at high risk for renal failure. The effect of the prune belly syndrome on the outcome of renal transplantation was evaluated in a retrospective study in which 8 transplant recipients with this syndrome were randomly matched with 13 control, nondiabetic transplant patients. The parameters evaluated were patient and graft survival, renal function and interval until transplantation. The patients were matched by computer for age at transplantation, date of transplantation, immunosuppressive therapy used and type of donor. Data were analyzed by the Gehan test. There was no statistically significant difference in patient deaths (1 versus 3), graft survival (75 versus 69%) or graft function between patients with the prune belly syndrome and controls. Patients with the prune belly syndrome waited a shorter interval for transplantation than did controls (no statistically significant difference) because the distensible abdominal wall characteristic of the syndrome permits placement of an adult kidney in a young child. The prune belly syndrome did not adversely affect the outcome of renal transplantation in these patients.

Adolescent↗
PubMed1989

Strategies for optimizing growth in children with kidney transplants.

Children with a well-functioning graft continue to show growth retardation even with low-dose prednisone. We have attempted to utilize the steroid-sparing effect of cyclosporine by discontinuing prednisone after graft stabilization. Since 1983, 53 children have received cyclosporine as primary immunosuppressant for renal graft maintenance. The children, aged 6 months to 18 years, received 60 transplants. One-year and four-year patient survival for cadaveric transplants was 91% and 91%, compared with 96% and 96% for living related transplants. One-year and four-year graft survivals were 82% and 65% for cadaveric transplants (n = 25), compared with 91% and 63% for living related transplants (n = 35). Of 53 patients, 23 were able to discontinue prednisone and be maintained on monodrug cyclosporine therapy, and 21 of the 53 patients had growth hormone measured using L-dopa stimulation. In patients receiving more than 5 mg of prednisone daily, growth hormone levels were lower than normal (less than 10 ng/ml). Of 15 patients who had discontinued prednisone for more than 6 months, 13 showed accelerated growth by improvement in their standard deviation scores. In 4 pubescent children with growth retardation and need for maintenance prednisone, accelerated growth occurred following growth hormone administration for 3-6 months. Based on these data we suggest that (1) discontinuation of even very small doses of prednisone may be essential for normalizing growth hormone response to L-dopa and (2) further studies are needed to exploit the growth stimulation effect of recombinant growth hormone in transplanted children.

Adolescent↗
PubMed1989

Studies on active immunization with self antigens. II. Production of antibody related to hapten substitution.

BALB/c mice were injected during neonatal life with conjugates in buffered physiological saline, prepared by coupling trinitrophenyl groups (TNP) at various densities to either syngeneic mouse serum albumin (TNP-MSA) or xenogeneic bovine serum albumin (TNP-BSA). Serum samples were obtained on days 30 and 60 after birth, on days 75 and 88 after two booster injections, and monoclonal antibodies were prepared from spleens of neonatally treated mice. The antibody titres, isotypes, and specificities were evaluated by enzyme-immunoassay. It was found that the extent of the anti-TNP immune response to TNP-MSA conjugates depends on the degree of hapten substitution, which is not the case for the anti-TNP-BSA. All the TNP-MSA conjugates induced mainly IgG and only a few IgM antibodies. These antibodies reacted essentially with the TNP group but seemed to have a higher avidity for the TNP-protein conjugate used in their induction. During the course of the immunization, decreasing quantities of TNP-MSA conjugates were needed to inhibit antibody binding. A large amount of monoclonal anti-TNP antibodies was found in hybridomas obtained after neonatal treatment either with TNP-MSA or TNP-BSA. Therefore, it appears that the anti-TNP immune response obtained after antigenic stimulation with sufficiently substituted TNP-MSA conjugates possesses all the characteristics of a normally occurring humoral immune response.

Animals↗
PubMed1989

Transformation of the dermatophyte Trichophyton mentagrophytes to hygromycin B resistance.

A transformation system for the ringworm-producing dermatophyte Trichophyton mentagrophytes has been developed. The system employs the plasmid pHIS, which contains a bacterial hygromycin B phosphotransferase gene linked to Cochliobolus heterostrophus regulatory sequences (B. G. Turgeon, R. C. Garber, and O. C. Yoder, Mol. Cell. Biol. 7:3297-3305, 1987). This plasmid confers hygromycin B resistance to T. mentagrophytes. The DNA was stably integrated into the fungal genome, and the number and sites of integrations varied among transformants. Transformant clones were capable of infecting guinea pigs. This system opens the way for the molecular genetic analysis of the interaction of T. mentagrophytes with epithelial animal tissues.

Animals↗
PubMed1989

Evidence for tissue diffusion limitation of VO2max in normal humans.

We recently found [at approximately 90% maximal O2 consumption (VO2max)] that as inspiratory PO2 (PIO2) was reduced, VO2 and mixed venous PO2 (PVO2) fell together along a straight line through the origin, suggesting tissue diffusion limitation of VO2max. To extend these observations to VO2max and directly examine effluent venous blood from muscle, six normal men cycled at VO2max while breathing air, 15% O2 and 12% O2 in random order on a single day. From femoral venous, mixed venous, and radial arterial samples, we measured PO2, PCO2, pH, and lactate and computed mean muscle capillary PO2 by Bohr integration between arterial (PaO2) and femoral venous PO2 (PfvO2). VO2 and CO2 production (VCO2) were measured by expired gas analysis, VO2max averaged 61.5 +/- 6.2 (air), 48.6 +/- 4.8 (15% O2), and 38.1 +/- 4.1 (12% O2) ml.kg-1.min-1. Corresponding values were 16.8 +/- 5.6, 14.4 +/- 5.0, and 12.0 +/- 5.0 Torr for PfVO2; 23.6 +/- 3.2, 19.1 +/- 4.2, and 16.2 +/- 3.5 Torr for PVO2; and 38.5 +/- 5.4, 30.3 +/- 4.1, and 24.5 +/- 3.6 Torr for muscle capillary PO2 (PmCO2). Each of the PO2 variables was linearly related to VO2max (r = 0.99 each), with an intercept not different from the origin. Similar results were obtained when the subjects were pushed to a work load 30 W higher to ensure that VO2max had been achieved. By extending our prior observations 1) to maximum VO2 and 2) by direct sampling of femoral venous blood, we conclude that tissue diffusion limitation of VO2max may be present in normal humans. In addition, since PVO2, PfVO2, and PmCO2 all linearly relate to VO2max, we suggest that whichever of these is most readily obtained is acceptable for further evaluation of the hypothesis.

Adult↗
PubMed1989

Prune belly syndrome: clinicopathologic study of 29 cases.

The clinical course and the pathologic features of 29 patients with the prune belly syndrome (PBS) are reviewed. There were 26 males and 3 females. In addition to the classical triad of deficient abdominal musculature, urinary tract abnormalities, and cryptorchidism, a broader spectrum of other defects was found including musculoskeletal (58%) and gastrointestinal (31%) abnormalities. Genital anomalies were present in all three female patients. Many of these defects may be inapparent at birth, but are the cause of morbidity and mortality later in life. Severe urinary tract maldevelopment and pulmonary hypoplasia as part of the oligohydramnios syndrome was the most common cause of perinatal deaths. In these patients, major portions of the renal parenchyma were dysplastic, but in survivors, renal dysplasia, when present, was minor by comparison, and affected less than 1/3 of the parenchyma. Although several questions remain unanswered, we believe that the PBS results from the effect of one or more teratogenic agents on the somatic mesoderm, producing inappropriate mesenchymal development and inadequate mesenchymal-epithelial interactions that lead to abnormal development and dilatation of some of its derivatives (abdominal muscles, ureter, bladder, prostate, urethra, and gubernaculum). Although abnormalities in derivatives of the intermediate mesoderm (kidney) may also be produced by the injurious agent(s), they are more likely a result of urinary obstruction. Abnormalities in other organs and systems are the consequence of oligohydramnios.

Abnormalities, Multiple↗
PubMed1989

The immunomodulatory effect of CCA (N-(2-carboxyphenyl)-4-chloroanthranilic acid disodium salt) on IgG antibody response in mice immunized with ovalbumin.

CCA(N-(2-carboxyphenyl)-4-chloroanthranilic acid disodium salt is a new synthetic compound which structurally resembles mefenamic acid. CCA induces inhibition of the adjuvant arthritis in rats and has been reported as activator of suppressor T lymphocytes. These findings stimulated to us to elucidate whether or not CCA possesses inhibitory effects on immunoglobulin E (IgE) production, an immunological system in which T suppressor cells play a cardinal role. Mice F1 (BALB/c x C57BL/6J) and C3H/A were immunized using the procedure of several s.c. injections with low dose of ovalbumin and aluminium hydroxide gel. CCA (5 mg/kg and 50 mg/kg) was administered to mice several weeks by oral route. The titers of IgE were compared in controls and treated animals using the method of passive cutaneous anaphylaxis (PCA) in rats. At a dose of 5 mg/kg CCA reduced partially the titers of IgE in treated animals with respect to controls and at a dose of 50 mg/kg this inhibition was more pronounced. These results support a potential usefulness of CCA in bronchial asthma and other immediate type allergic disorders.

Animals↗
PubMed1988

Monoclonal antibodies specific to apical surfaces of rat alveolar type I cells bind to surfaces of cultured, but not freshly isolated, type II cells.

The alveolar surface of the lung is lined by two classes of epithelial cells, type I and type II cells. Type I cells cover more than 97% of the alveolar surface. Although this cell type is felt to be essential for normal gas exchange, neither unique identifying characteristics nor functions have been described for the type I cell. We have produced monoclonal antibodies to (a) component(s) of molecular weight 40,000 and 42,000 of the apical surface of rat alveolar type I cells. The antibodies are specific to the lung in Western blots of organ homogenates. In immunocytochemical studies of frozen lung at the level of both light and electron microscopy, the monoclonal antibodies appear to react specifically with the apical plasma membrane of type I cells. Airway, vascular, interstitial cells, type II cells and macrophages are not immunoreactive. Western blots of isolated type I cells (approx. 70% pure) also demonstrate immunoreactivity at molecular weights of 40,000 and 42,000. When the lung is injured, type I cells may be damaged and sloughed from the alveolar surface. Alveolar repair occurs when the second type of alveolar cell, the type II cell, divides. Cell progeny may retain type II cell morphology or may differentiate into type I cells. Western blots of freshly isolated type II cells (approx. 85% pure) do not display immunoreactivity with our monoclonal antibodies. However, type II cells maintained in culture acquire immunoreactivity to monoclonal antibodies, demonstrating that type II cells in vitro have the capacity to develop a characteristic associated with type I cells in situ. The availability of markers for a specific membrane component of type I cells should facilitate the study of many questions on alveolar functions, development and response to injury.

Animals↗