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Biomedical subjects

R Gonzalez

Publications and source records attributed to R Gonzalez.

At least 289 records · Page 16Linked to original sources
PubMed1987

Upper urinary tract obstruction in children: current controversies in diagnosis.

Our approach to the evaluation and treatment of children with upper urinary tract obstruction is shown in Figure 10. The following guiding principles should be remembered: 1. Intravenous urography and renal ultrasonography are usually insufficient to establish the diagnosis of obstruction in an asymptomatic patient. 2. Diuresis-enhanced renography is diagnostic in nonobstructed systems (spontaneous excretion of the radioisotope before the injection of furosemide) or unequivocally obstructed systems (no excretion of the radioisotope after injection of furosemide). 3. If the results of diuresis-enhanced renography are equivocal, a patient should be evaluated by pressure flow studies before surgical correction is undertaken or a diagnosis of no obstruction. 4. Diuresis-enhanced renography is extremely useful in followup and in evaluating surgical results.

Child↗
PubMed1987

Pulmonary surfactant and its components inhibit secretion of phosphatidylcholine from cultured rat alveolar type II cells.

Pulmonary surfactant is synthesized and secreted by alveolar type II cells. Radioactive phosphatidylcholine has been used as a marker for surfactant secretion. We report findings that suggest that surfactant inhibits secretion of 3H-labeled phosphatidylcholine by cultured rat type II cells. The lipid components and the surfactant protein group of Mr 26,000-36,000 (SP 26-36) inhibit secretion to different extents. Surfactant lipids do not completely inhibit release; in concentrations of 100 micrograms/ml, lipids inhibit stimulated secretion by 40%. SP 26-36 inhibits release with an EC50 of 0.1 microgram/ml. At concentrations of 1.0 microgram/ml, SP 26-36 inhibits basal secretion and reduces to basal levels secretion stimulated by terbutaline, phorbol 12-myristate 13-acetate, and the ionophore A23187. The inhibitory effect of SP 26-36 can be blocked by washing type II cells after adding SP 26-36, by heating the proteins to 100 degrees C for 10 min, by adding antiserum specific to SP 26-36, or by incubating cells in the presence of 0.2 mM EGTA. SP 26-36 isolated from canine and human sources also inhibits phosphatidylcholine release from rat type II cells. Neither type I collagen nor serum apolipoprotein A-1 inhibits secretion. These findings are compatible with the hypothesis that surfactant secretion is under feedback regulatory control.

Animals↗
PubMed1987

Grading of reflux by radionuclide cystography.

Over a three-year period, radionuclide cystography (RC) was performed on 145 patients. Of these, 31 nephroureteral units in 25 patients demonstrated vesicoureteral reflux by RC and also by radiographic cystography (XC). The RC and XC studies were performed within three months of one another. The grading of reflux was determined by RC and then compared with that of XC using the criteria for grading as established by the International Reflux Study Committee (IRSC). Of 18 nephroureteral units in 14 patients with grade II reflux by XC, 14 were similarly graded by RC (78%). Of five nephroureteral units in five patients with grade III reflux by XC, the correlation by RC was 100%. However, when grades II and III were combined into a single category of low-grade reflux, the correlation achieved between the two cystographic techniques was 100%. Of five nephroureteral units in four patients with grade IV reflux by XC, the correlation was 60%, and in three units in two patients with grade V reflux the correlation was 100%. When grades IV and V are combined into a category of high-grade reflux, a correlation of 100% is achieved. When the reflux is graded into the five IRSC categories, the overall unequivocal correlation between the two studies is 80%. However, when only two categories are used (low grade = grades II and III, and high grade = grades IV and V), a correlation of 100% is obtained.

Adolescent↗
PubMed1987

Effect of hemodialysis on protein C levels.

The immunological functions of antithrombin III and protein C were studied in 8 patients before, during and after hemodialysis. After dialysis a significant decrease in protein C and antithrombin III levels was seen. The changes observed in both proteins after hemodialysis should be considered as a component in the genesis of the hypercoagulation state in these patients.

Adult↗
PubMed1987

[Blunt abdominal trauma caused by child abuse].

We report about 3 boys under 4 years of age with abdominal blunt trauma following child abuse admitted to our clinic with different diagnoses. Common were fresh or older haematomas, burn wounds, for which the parents had no plausible explanation. The children had no skeletal or intracranial lesions, but they developed abdominal pain, which became worse in the absence of the parents. X-ray and the clinical course lead us to laparatomy. In all cases we found lesions of the intestines, especially near the duodenojejunal flexure, hepatoduodenal ligament, root of the mesentery, mesocolon and retroperitoneum, in one case a pancrease rupture. All these lesions were caused by child abuse. We want to point out the problem in the diagnosis of battered child syndrome, especially of the abdominal blunt trauma.

Abdominal Injuries↗
PubMed1986

Urinary undiversion: indications, technique and results in 50 cases.

We present our experience with reconstruction of the diverted urinary tract in 50 patients divided into 3 groups according to the presence of neurogenic bladder dysfunction, severe renal failure or normally innervated bladders and sphincters with normal renal function. The over-all success rate of anatomical and functional reconstruction was 88 per cent and we expect it ultimately to increase to 94 per cent. However, because of a 2 per cent mortality rate and a 16 per cent major complication rate, we recommend that all other therapeutic options be considered carefully before undertaking urinary undiversion when the reconstruction involves use of intestinal segments.

Adolescent↗
PubMed1986

Pediatric urethral reconstruction without proximal diversion.

A new method of transurethral drainage was used in 36 consecutive patients who underwent urethral reconstruction for repair of hypospadias and epispadias. The surgical procedures included 16 island flap urethroplasties, 15 distal urethral repairs with Mathieu's technique, 3 epispadias repairs and 2 urethroplasties with a modified Thiersch-Duplay technique. To accomplish urinary drainage in all cases a 7 or 10F silicone tube with multiple perforations was inserted proximal to the bladder neck and through the repair, and cut 2 mm. distal to the urethral meatus. The tube was secured to the meatus with loosely tied 4-zero polypropylene sutures and allowed to drain into a diaper. Satisfactory results were obtained in all patients. Complications included a small urethrocutaneous fistula in 6 children, a distal urethral stricture in 1 and severe bladder spasms in 2. The incidence of fistula formation did not appear to increase with this method of urinary drainage. Advantages of the method included a decreased hospital stay and minimal discomfort.

Child, Preschool↗
PubMed1986

Vesicoureteral reflux in children with myelodysplasia: natural history and results of treatment.

A total of 58 children with myelodysplasia underwent radiographic and cystometric evaluation and were followed periodically for an average of 58 months. Of this group 30 (52 per cent) demonstrated vesicoureteral reflux, including 16 with low grade and 14 with high grade reflux. In 6 children low grade vesicoureteral reflux resolved with prophylactic antibacterials only, while decompressive treatment was required in 6, antireflux surgery was required in 2 and 2 were lost to followup. Despite adequate decompressive treatment 12 of the 14 children with high grade vesicoureteral reflux required an antireflux operation and 2 were lost to followup. Among those who underwent an operation there has been no recurrent reflux but 3 children have shown evidence of upper urinary tract deterioration. We describe our current approach to the treatment of vesicoureteral reflux in children with neurogenic bladder dysfunction and suggest a management protocol based on urodynamic findings.

Anti-Bacterial Agents↗
PubMed1986

Influence of intestinal segment and configuration on the outcome of augmentation enterocystoplasty.

The clinical and urodynamic results of enterocystoplasty were compared in 3 groups of patients in which the intact ileocecal segment (10 patients), tubular sigmoid segment (16) or sigmoid cup-patch segment (8) was used. In all 3 groups the upper urinary tract and renal function improved or remained stable, and the functional bladder capacity increased. All patients experienced involuntary, volume-dependent vesical contractions of comparable intensity 3 months postoperatively. After a mean followup of 19.4 +/- 8.9 months only 12 per cent of the patients with a cup-patch configuration demonstrated volume-dependent contractions, compared to all patients with ileocecal cystoplasty and 94 per cent with sigmoid tubular cystoplasty. The intensity of these contractions was significantly less in the cup-patch configuration group compared to the other groups. Patients with cup-patch cystoplasty achieved a significantly higher rate of urinary continence than those in the other 2 groups. It appears that the sigmoid cup-patch configuration may provide a lower pressure system and better continence compared to the intact ileocecal or tubular sigmoid segment, although the latter techniques have specific applications when confronted with a wide gap between the ureters and bladder or when dilated ureters require anastomosis to the bowel.

Adolescent↗
PubMed1986

The value of urodynamic testing in the management of neonates with myelodysplasia: a prospective study.

We report the results of a prospective study conducted to identify neonates with myelomeningocele at risk for changes in the upper urinary tract. Thirty newborns underwent full urological evaluation and were followed for a mean period of 18.2 months. The initial studies included voiding cystourethrography, excretory urography and urodynamic tests. Followup consisted of periodic radiographic studies and repeat urodynamic testing if any changes were observed. According to urodynamic findings the patients were divided into 2 groups: group 1 consisted of 9 neonates (30 per cent) with detrusor-sphincter dyssynergia and high pressure, decreased-compliance bladders, and group 2 consisted of 21 children (70 per cent) with atonic bladders and low pressure, reduced-compliance bladders without dyssynergia. In group 1, 55 per cent of the patients had initially abnormal radiographic findings in contrast with 28.5 per cent in group 2. Anticholinergic drugs and clean intermittent catheterization or vesicostomy reversed the changes in 40 per cent of the children in group 1, 40 per cent remained stable and 20 per cent showed signs of deterioration. Four children in group 1 with normal neonatal radiographs were treated expectantly and at followup they all showed signs of deterioration. The neonates in group 2 with normal radiographic findings remained normal at followup. Of those who initially had changes 67 per cent reversed to normal without treatment, 17 per cent remained stable and 17 per cent had deterioration. Newborns with detrusor-sphincter dyssynergia or high pressure, reduced-compliance bladders are at high risk of having upper urinary tract changes and require preventive decompressive treatment. Children with atonic or low pressure, reduced-compliance bladders and those with a coordinated bladder and sphincter are at low risk and need only close followup.

Electromyography↗
PubMed1986

Carcinoma of the prostate with atypical immunohistological features. Clinical and histologic correlates.

In seven patients with undifferentiated carcinoma of the prostate, the immunohistochemical stain for prostate-specific antigen was negative. The stain for prostatic acid phosphatase done on the same tissue samples was diffusely positive in three, focally positive in three, and negative in one. Only the three with diffusely positive immunostaining had elevated serum acid phosphatase levels, although five had evidence of metastatic disease. All seven neoplasms were histologically similar, being composed of large cells with large nuclei, a moderate amount of cytoplasm, and indistinct cell borders. All tumors grew as broad sheets within the prostatic stroma as well as in the prostatic urethra; in six cases. Thus, prostatic carcinoma with this histologic pattern frequently loses prostate-specific antigen immunoreactivity. Awareness of this occurrence should prevent a misdiagnosis of urothelial carcinoma in such cases. The prostatic origin of these neoplasms can usually be verified by prostatic acid phosphatase immunostaining, which proves to be more sensitive in this particular setting.

Acid Phosphatase↗
PubMed1986

An improved method for isolating type II cells in high yield and purity.

A method has been developed for isolating alveolar type II cells by digesting lung tissue with elastase and "panning" the resultant cell suspension on plates coated with IgG. This method provides both high yield and purity of type II cells. In 50 experiments with rats, we obtained 35 +/- 11 X 10(6) cells/rat, 89 +/- 4% of which were type II cells (mean +/- SD). Type II cells isolated by "panning" adhered more rapidly and completely in tissue culture than did cells isolated by centrifugation over discontinuous density gradients of metrizamide. The "panning" method is superior to other methods for isolating type II cells in that it provides a population of type II cells of both high yield and high purity. The method is fast, reproducible, and easily adaptable to isolating type II cells from species other than rats.

Animals↗
PubMed1986

Prevention of basement membrane thickening in retinal capillaries by a novel inhibitor of aldose reductase, tolrestat.

A diabetic-like thickening of retinal capillary basement membranes induced in rats fed for 207 consecutive days a diet containing 50% galactose was prevented by the addition to the diet of tolrestat, a potent, structurally novel inhibitor of aldose reductase. Analysis of electron micrographs (X 25,000) of capillaries from the outer plexiform layer of the retina by computer planimetry showed that the basement membranes were approximately twofold thicker in rats fed galactose than in those fed either a standard diet or a diet containing galactose and tolrestat in doses of 43 or 57 mg/kg/day. The thickening of basement membranes in galactose-fed rats was accompanied by other ultrastructural alterations mimicking changes typical of diabetic microangiopathy, such as multilamination and the formation of vacuoles and dense inclusions. Therefore, the galactosemic rat represents a useful model for studying basement membrane-related complications of diabetes and their possible prevention by aldose reductase inhibitors.

Aldehyde Reductase↗