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Biomedical subjects

R Gonzalez

Publications and source records attributed to R Gonzalez.

At least 109 records · Page 6Linked to original sources
PubMed1997

Results of the Mitrofanoff procedure in urinary tract reconstruction in children.

OBJECTIVES: To evaluate the success and long-term complications associated with the use of continent catheterizable conduits based on the Mitrofanoff principle in children. PATIENTS AND METHODS: The records of 43 patients (21 female and 22 male) who underwent the construction of a continent catheterizable stoma based on the Mitrofanoff principle between 1987 and 1996 were reviewed retrospectively. The mean age at surgery was 10 years (range 3-21) and the mean follow-up was 3 years (range 0.5-6.5). Twenty-eight of the 43 children underwent augmentation cystoplasty in conjunction with the Mitrofanoff procedure, using ileum in 17, sigmoid in seven, caecum in two and stomach in one; detrusormyectomy was performed in one child. Fifteen patients had only a continent catheterizable stoma formed. The most common type of conduit was appendicovesicostomy (36 of 43 children): other conduits were constructed with ureter (four), tapered ileum (two) and fallopian tube (one). RESULTS: Stomal continence was achieved in 42 of 43 patients (98%). The most common late complication was difficulty in catheterization, which occurred in 14 patients (32%). Stomal prolapse requiring revision occurred in one patient (2%). Conduit dilatation was initially attempted in all patients with difficult catheterization, although it failed in 11 who then required surgical revision. Therefore, the overall revision rate was 28% (12 of 43). The site of stomal placement (umbilical or abdominal) did not significantly influence the risk of difficulty with catheterization. CONCLUSION: The Mitrofanoff procedure can simplify catheterization in children who are dependent upon intermittent catheterization. The vermiform appendix appears to be the best source for constructing the conduit. While stomal continence is excellent, conduit stenosis remains a frequent complication regardless of stomal location.

Adolescent↗
PubMed1997

Intermittent self-catheterization by quadriplegic patients via a catheterizable Mitrofanoff channel.

PURPOSE: Neurogenic bladder due to cervical spinal cord injury is often best managed by clean intermittent catheterization. Limited upper extremity function makes patients with quadriplegia dependent on caregivers for clean intermittent catheterization. The Mitrofanoff umbilical appendicovesicostomy provides easy access to the bladder in patients with all types of access difficulty. We evaluated the Mitrofanoff umbilical appendicovesicostomy in 7 patients with quadriplegia. MATERIALS AND METHODS: Four men and 3 women with cervical spinal cord injury underwent the Mitrofanoff umbilical appendicovesicostomy with appendix (5) or ileum (2). RESULTS: All patients are continent and able to self-catheterize via the umbilical stoma. In 1 patient with an ileal Mitrofanoff umbilical appendicovesicostomy umbilical incontinence was repaired surgically and stomal stenosis developed in 1, which required stomal revision. All patients use the stoma regularly. Four patients have moved out of care facilities and are living more independently. CONCLUSIONS: The Mitrofanoff catheterizable channel is a valuable option for bladder management in patients with quadriplegia. Clean intermittent self-catheterization allows these patients independent function and facilitates their return to productive lives outside care facilities.

Adult↗
PubMed1996

Adrenergic activation of phospholipase D in primary rat astrocytes.

Phospholipase D (PLD) activity was investigated in astrocytes prepared from newborn rat cerebral cortex using the transphosphatidylation assay. Basal PLD activity was measurable and was found to be enhanced by ATP, carbachol and noradrenaline. The activation by noradrenaline (EC50, 0.68 microM) was mimicked by methoxamine (EC50, 65 microM), an alpha 1-specific adrenergic agonist, and was inhibited by prazosine, an alpha 1-specific adrenergic antagonist. Clonidin, an alpha 2-adrenergic agonist, slightly lowered PLD activity whereas beta-adrenergic drugs were without effect. Experiments with mitogens indicate that PLD activation in astrocytes may be involved in the control of astrocytic cell proliferation.

Animals↗
PubMed1996

Synchronous bilateral Wilms' tumor in a neonate.

OBJECTIVES: Wilms' tumor is the most common solid abdominal tumor of childhood. Wilms' tumor is extremely rare in the neonate, with less than 20 well-documented cases. No bilateral lesions in neonates have been described in the literature. METHODS: We report on a neonate who presented with synchronous bilateral Wilms' tumors. RESULTS: Child underwent bilateral partial nephrectomy, followed by standard chemotherapy, and is now well 2 years after completion of the therapy without any evidence for recurrent disease. CONCLUSIONS: Wilms' tumor should be included in the differential diagnosis of the solid renal mass in the neonate.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Measuring ordinal association in situations that contain tied scores.

The construal of ties is critical for assessing the association between two variables. Ties should be excluded when the investigator's data-collection procedure forces ties to occur (e.g., a J-place rating scale is used to rate K items, with J < K; a criterion variable contains fewer than K possible outcomes per item). Four measures arising from excluding or including ties on 2 ordinal variables are Goodman & Kruskal's G, Somer's dyx, Kim's dyx, and Wilson's e. In contrast to measures having variance-accounted-for interpretations, probabilistic interpretations developed here can be applied meaningfully both to ordinal-scaled variables and to stronger scales. Recommendations are offered for which measure to use in various situations.

Humans↗
PubMed1996

Is there a best alternative to treating the obstructed upper pole?

PURPOSE: We addressed whether salvage of upper pole renal units in comparison to partial nephrectomy affects differential renal function in patients with a duplicated obstructed upper pole. MATERIALS AND METHODS: We retrospectively reviewed the records of all children who underwent surgery for a unilateral obstructed duplicated kidney at our institution from 1988 to 1995. Patients were evaluated with respect to postoperative complications, reoperation rate and percent change in differential renal function of the obstructed duplicated kidney, as determined by nuclear renography. RESULTS: We identified 46 patients with a unilateral obstructed upper pole of a duplicated kidney who were divided into 2 groups. Group 1 (12 patients) underwent an upper pole salvage procedure, that is ureteropyelostomy or ureteroureterostomy, and group 2 (31 patients) underwent partial nephrectomy. Three reoperations (25%) were performed in group 1 and 1 (4%) was done in group 2. Postoperative symptomatic urinary tract infections were diagnosed in 3 group 1 patients (25%) and in 2 (8%) in group 2. Average change in ipsilateral renal function in the 8 patients who underwent upper pole salvage procedures was 2.25 +/- 2.34% (range -6 to 12). In the 8 patients who underwent upper pole nephrectomy and who also had postoperative renal scans average change in function was -1.25 +/- 4.51% (range -23 to +16). CONCLUSIONS: There was no statistically significant loss of relative renal function in patients treated with partial nephrectomy and no significant gain in relative renal function in those treated with an upper pole salvage procedure. The reoperation rate was higher in the upper pole salvage than in the partial nephrectomy group (25 versus 4%). While not statistically significant, we believe that this rate is clinically important. We think that partial nephrectomy should remain the preferred treatment for most patients with obstructed duplicated kidneys.

Adolescent↗
PubMed1996

Double onlay preputial flap for proximal hypospadias repair.

PURPOSE: We describe a new technique for primary repair of proximal hypospadias. The double onlay preputial flap combines the principles of onlay urethroplasty and the double face preputial flap, namely preservation of the urethral plate and use of a total preputial flap. MATERIALS AND METHODS: Common problems of classic onlay urethroplasty, including rotation and asymmetry of the penile shaft when the preputial flap is brought laterally around the shaft and the viability of the Byars flaps after dissecting the pedicle for the onlay flap, are avoided with this technique by passing the penis through a buttonhole incision in the pedicle of the total preputial flap. Onlay urethroplasty is performed using a secondary flap outlined from the total preputial flap. The remainder of the total preputial flap tissue is used to cover the ventral skin defect. RESULTS: Since June 1994, 18 patients 6 months to 9 years old (median age 10 months) underwent primary hypospadias repair with the double onlay preputial flap technique, representing 15% of all repairs performed. Complications included a urethrocutaneous fistula, persistent chordee, a recessed meatus and a urethral diverticulum in 1 patient each. In all cases complications were corrected surgically with minor procedures. No patient had urethral stricture. Functional and cosmetic results were satisfactory in all patients. CONCLUSIONS: This technique yields good functional and cosmetic results for proximal hypospadias repair.

Child↗
PubMed1996

Effect sizes and p values: what should be reported and what should be replicated?

Despite publication of many well-argued critiques of null hypothesis testing (NHT), behavioral science researchers continue to rely heavily on this set of practices. Although we agree with most critics' catalogs of NHT's flaws, this article also takes the unusual stance of identifying virtues that may explain why NHT continues to be so extensively used. These virtues include providing results in the form of a dichotomous (yes/no) hypothesis evaluation and providing an index (p value) that has a justifiable mapping onto confidence in repeatability of a null hypothesis rejection. The most-criticized flaws of NHT can be avoided when the importance of a hypothesis, rather than the p value of its test, is used to determine that a finding is worthy of report, and when p approximately equal to .05 is treated as insufficient basis for confidence in the replicability of an isolated non-null finding. Together with many recent critics of NHT, we also urge reporting of important hypothesis tests in enough descriptive detail to permit secondary uses such as meta-analysis.

Psychophysiology↗
PubMed1996

Comparison of isoflurane, halothane and fentanyl in patients with decreased ejection fraction undergoing coronary surgery.

The aim of the study was to compare three anaesthetic agents in patients with ejection fraction below 0.40 subjected to coronary revascularization surgery. Twenty five elective coronary surgical patients with ejection fraction below 0.40 were prospectively studied. Premedication was pethidine 1 mg/kg and induction was fentanyl 0.03 mg/kg and pancuronium 0.1 mg/kg. The patients were randomized to one of three maintenance techniques (fentanyl, isoflurane or halothane). Radial arterial pressure, heart rate, right atrial pressure, pulmonary arterial and occluded pressures, and thermodilution cardiac output were measured, and cardiac index and resistance calculated, at the following times: before induction; 5 min after intubation; 2 min after sternotomy; immediately after discontinuation of bypass; 15 min afterwards; immediately after sternal closure; during suture of the skin; 5 min after arrival in the postoperative care unit; and 60 min postoperatively. Mean arterial pressure decreased significantly in the isoflurane group and nonsignificantly in the halothane group after induction. Cardiac index decreased significantly in the isoflurane group and nonsignificantly in the halothane group after induction and after sternotomy. Neither pressure nor flow decreased in patients receiving fentanyl. Following weaning from cardiopulmonary bypass, systemic vascular resistance decreased significantly in all groups. Cardiac index, however, did not increase above control values and arterial pressure consequently decreased; there was no significant difference between groups.

Adjuvants, Anesthesia↗
PubMed1996

Fetal therapy for obstructive uropathy: diagnosis specific outcomes [corrected].

PURPOSE: Attempts to evaluate prenatal vesico-amniotic shunt therapy have been hampered by inconsistencies in patient selection, treatment and termination criteria, and outcomes measurement. Outcomes have generally been measured against those of patients with postnatally detected posterior urethral valves. The purpose of this report was to evaluate the influence of the underlying diagnosis on the clinical outcomes of fetuses undergoing evaluation for prenatal intervention for suspected obstructive uropathy. Furthermore, specific outcomes diagnosis was compared to the published natural history of these disorders to begin to establish a basis for measuring the efficacy of prenatal intervention. MATERIALS AND METHODS: We retrospectively reviewed the outcomes of 55 consecutive patients undergoing prenatal evaluation using structured outcome measures stratified by specific diagnoses to provide a comparison to the reported natural history for each underlying disorder. RESULTS: All fetuses had early onset of oligohydramnios/anhydramnios representing the worst end of the spectrum. Compared to postnatally diagnosed patients, prenatally diagnosed patients with posterior urethral valves had lower survival (60 versus 93%) but similar postnatal renal failure rates (31 versus 33%). Cases of prenatally detected but untreated posterior urethral valves had a 44% renal failure rate. In fetuses with the prune-belly syndrome survival (86 versus 72%) and renal function rates (17 versus 27% renal failure) compared favorably with the postnatal experience, although 55% of the cases had significant urethral obstruction. All patients with urethral atresia died. CONCLUSIONS: The underlying etiology of obstruction appears to have a marked influence on clinical outcome independently of treatment. When evaluated by specific diagnosis, intervention appears to provide outcomes in these high risk fetuses that are comparable to those for disease detected postnatally. Interpretation of series that do not distinguish cases by onset, severity and specific pathological process is problematic. Greater standardization of patient selection, treatment and outcome measurement, including the use of specific diagnoses, is necessary to allow an accurate assessment of the efficacy and proper role of fetal therapy.

Anastomosis, Surgical↗
PubMed1996

Long-term intravesical oxybutynin chloride therapy in children with myelodysplasia.

PURPOSE: We evaluated the clinical use of long-term intravesical oxybutynin chloride in the treatment of neurogenic bladder dysfunction in children with myelodysplasia who could not tolerate oral anticholinergics. MATERIALS AND METHODS: We retrospectively reviewed the records of all patients recommended for intravesical oxybutynin chloride therapy. A total of 12 girls and 18 boys 1 to 17 years old was recruited for study. Oxybutynin chloride (5 mg.) was instilled 2 times daily and pretreatment cystograms were compared to followup urodynamic studies. Duration of therapy was 2 to 26 months (mean 13, median 12). RESULTS: Mean total capacity plus or minus standard deviation increased from 209 +/- 103 to 282 +/- 148 ml. (p < 0.01), mean safe capacity increased from 157 +/- 105 to 234 +/- 147 ml. (p < 0.01) and mean age adjusted safe capacity increased from 76 +/- 36 to 115 +/- 62%. Of the 29 patients who were incontinent 3 (10%) achieved continence and 19 (65%) reported a decreased use of sanitary pads. None of the patients had systemic side effects related to intravesical treatment. CONCLUSIONS: We believe that intravesical oxybutynin chloride is a viable treatment option for patients with myelodysplasia in whom oral therapy fails.

Administration, Intravesical↗
PubMed1996

Purification of a lipase from Acinetobacter calcoaceticus AAC323-1 by hydrophobic-interaction methods.

The performance of hydrophobic-interaction chromatography (HIC) for the purification of Acinetobacter calcoaceticus AAC323-1 lipase was compared with that of various aqueous two-phase systems. While a 42% lipase yield with a purification factor of 140 could be recovered by HIC, higher yields were achieved by using aqueous two-phase systems, either those formed by poly(ethylene glycol) and dextran or those based upon the use of a detergent. Triton X-114-based aqueous two-phase partition showed the best performance, with a yield of 81% and a purification factor of 68. Further detergent removal was easily achieved with an adsorbent, with no significant decrease in yields. Owing to its simplicity, the method should be easy to scale-up.

Acinetobacter calcoaceticus↗
PubMed1995

Differences between nuclear run-off and mRNA levels for multidrug resistance gene expression in the cephalocaudal axis of the mouse intestine.

P-glycoprotein is a multidrug transporter encoded by the mdr3 gene in the mouse intestinal epithelium. The aims of this study were to characterize the mdr3 gene expression in the cephalocaudal axis of the intestine in adult animals and during perinatal development, and to define the molecular mechanism responsible for the heterogeneous expression of the gene along the cephalocaudal axis. RNA extracted from stomach, duodenum, jejunum, ileum, cecum and colon was hybridized by slot blot and Northern blot using a mdr3 cDNA probe. The regulation of gene expression was investigated examining the rate of transcription by nuclear run-off analysis. Transport studies of rhodamine 123, a substrate of P-glycoprotein, were performed in everted jejunum and ileum. The level of mdr3 mRNA and P-glycoprotein found in ileum was 6-fold higher than the level found in duodenum. The regional pattern of mdr3 gene expression is established in the intestine of 10-day-old animals. Similar mdr3 hybridization signal in nuclear run-off assay was found in nuclei of enterocytes isolated from jejunum and ileum, suggesting that the heterogeneous expression of the mdr3 gene in the cephalocaudal axis of the small bowel may be predominantly regulated at the post-transcriptional level. Transport rate of rhodamine 123 from the serosal to mucosal side in everted ileum was higher than the rate of transport found in jejunum. These results indicate that enterocytes of the ileum may be more actively involved in the P-glycoprotein-mediated transport of xenobiotics into the intestinal lumen.

ATP Binding Cassette Transporter, Subfamily B, Mem↗