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Biomedical subjects

C A Peters

Publications and source records attributed to C A Peters.

At least 127 records · Page 7Linked to original sources
PubMed1989

The use of rectus fascia to manage urinary incontinence.

The surgical management of urinary incontinence in children is one of the most difficult challenges facing pediatric urologists today. We have critically looked at our experience using a rectus fascial sling to prevent incontinence. Eleven girls (6 to 22 years old) with urinary incontinence from neurogenic bladder dysfunction (9), surgical injury to the bladder (1) or urogenital sinus abnormality (1) comprise this study. All had failed regimens of pharmacological therapy and intermittent catheterization. Three patients had undergone prior bladder neck reconstruction and 2 an augmentation cystoplasty in an attempt to control the incontinence. Urodynamic studies revealed several reasons for the continued wetting in these individuals: a changing neurological lesion leading to a loss of innervation and concomitantly lowered urethral resistance in 2 patients, adequate urethral resistance at rest but decreasing resistance with bladder filling in 4, no increase in urethral resistance with increases in abdominal pressure in 4 and urethral instability (a decrease in resistance following a cough or Valsalva's maneuver) in 1 apparently neurologically normal girl. Eight patients are dry 3 to 24 months postoperatively on intermittent catheterization. All have demonstrated either an increase in urethral resistance at rest or an adequate level of resistance during filling of the bladder or a sudden increase in abdominal pressure. Of the remaining 3 patients 1 is dry for 2 to 3 hours but then leakage occurs, 1 is improved but damp and 1 patient is wet 3 months postoperatively. The use of rectus fascia to improve outlet resistance seems to be a viable alternative in the management of incontinence in selected female subjects.

Adolescent↗
PubMed1989

Splitting the pubis for exposure in difficult reconstructions for incontinence.

In the last 13 years splitting the pubic symphysis has been used in 46 patients 1 to 32 years old for wide access to the bladder neck and entire urethra in female, or the bladder neck and urethra down into the bulb in male patients. Each patient had a complex problem to reconstruct and most had undergone a prior operation. Underlying pathological conditions included exstrophy in 16 patients, epispadias in 11, cloacal exstrophy in 6, posterior urethral valves in 3, severe trauma in 2, bilateral single ectopic ureters in 2, radical surgery for sarcoma in 2, myelodysplasia in 2, cloacal anomaly in 1 and iatrogenic injury of the urethra in 1. The pubis, or interpubic ligament in exstrophy cases, was divided in the midline. The pubic rami were spread with a laminectomy spreader to create a gap sufficient to operate on that segment of the urethra, which is usually not accessible with an intact pubis. No patient had a problem of nonunion or pubic osteitis after using this approach. This series includes 2 patients undergoing simultaneous iliac osteotomies for a widened symphysis pubis. In no patient was a segment of pubis resected, as has been used in transpubic repair of certain traumatic urethral strictures.

Adolescent↗
PubMed1989

Congenital obstructed megaureters in early infancy: diagnosis and treatment.

Fetal screening during maternal ultrasonography has changed the mode and age of presentation of congenital uropathies, particularly congenital obstructed megaureter. We studied 47 infants less than 8 months old with primary obstructed megaureter. Surgical correction in 42 patients with moderate to severe obstruction was performed at a mean age of 1.8 months in those detected prenatally and 3.8 months in those presenting after birth. All infants showed functional and structural urographic improvement with a mean followup of 2.3 years. Reflux was seen postoperatively in 8 patients, which subsided spontaneously in 3, continues to be followed in 2 and resulted in repeat reimplantation in 3. Five infants had mild obstruction, which was managed nonoperatively and 2 showed progressive obstruction, which required repair at ages 20 and 28 months. Repair of obstructed megaureters in early infancy improves renal drainage and offers the potential for preventing renal damage before the development of symptoms or infection. With proper attention to detail, excellent results may be achieved.

Dilatation, Pathologic↗
PubMed1989

The influence of reversible androgen deprivation on serum prostate-specific antigen levels in men with benign prostatic hyperplasia.

This study was designed to investigate the relationship of serum prostate-specific antigen to prostatic size and hormonal stimulation. Seven patients with benign prostatic hyperplasia were treated for six months with nafarelin acetate and then followed for an additional six months. Nafarelin acetate is a potent luteinizing-hormone-releasing hormone agonist which causes reversible testosterone deprivation resulting in involution of the prostate. During therapy and follow up, serum prostate-specific antigen correlated with: 1) serum testosterone (p less than 0.001); 2) quantity of prostatic epithelium (p less than 0.001); and 3) prostatic size (p less than 0.05). Before therapy, serum prostate-specific antigen (mean +/- SD) was 0.43 +/- 0.2 ng./ml. per gram of epithelium. This did not change significantly after six months of androgen deprivation (0.48 +/- 0.36), although the ratios of prostate-specific antigen to testosterone and to prostatic size each changed significantly. Despite testosterone levels in the castrate range at six months, five of seven patients had serum prostate-specific antigen concentrations above the female range and three of seven patients had prostatic biopsies containing columnar epithelium which stained positively for prostate-specific antigen. These results demonstrate that serum prostate-specific antigen is related to prostatic size, prostatic epithelial weight, and testosterone stimulation. However, prostatic size is not a good predictor of serum prostate-specific antigen because there is tremendous variation in the relative amount of epithelium in a prostate; in this study the ratio of prostatic size to epithelial weight varied threefold. Furthermore, although testosterone determines prostatic size and amount of prostatic epithelium, it may not totally control prostate-specific antigen production.

Aged↗
PubMed1989

Myths of antiemetic administration.

Chemotherapy as a treatment modality for cancer has dramatically improved outcomes for patients. However, to attain therapeutic benefit, side effects and toxicities must be endured. Among the most frequent and distressing side effects are nausea and vomiting. The experience of nausea and vomiting may become so devastating that patients will discontinue curative treatment modalities. The major responsibility of the nurse caring for a patient receiving chemotherapy treatment is to prevent or treat nausea and vomiting effectively. To accomplish this, the nurse needs to understand how nausea and vomiting occur, the action of antiemetics, and how to administer them. There are myths, beliefs, and/or practice behaviors that influence interventions for antiemetic administration. Successful nursing interventions to control nausea and vomiting may be less than optimal when myths instead of correct facts affect the interventions.

Antiemetics↗
PubMed1988

Epispadias and incontinence: the challenge of the small bladder.

The 12-year experience at our hospital with epispadias and incontinence is reviewed and attention is focused on the approach to patients with a small bladder capacity. Of 29 children 20 had incontinence associated with the epispadias (13 boys and 7 girls). A total of 15 patients underwent definitive management of the incontinence with a Young-Dees bladder neck reconstruction with or without ureteral reimplantation and they are evaluable. Nine patients (6 boys and 3 girls) had a bladder capacity that was believed to be inadequate for satisfactory bladder neck reconstruction (less than 60 ml.). To date, 7 of these children have undergone staged reconstruction with urethroplasty for epispadias as the initial operation. Bladder capacity increased 95 ml. on the average (range 60 to 140 ml.) after the urethroplasty. No child had hydronephrosis before or after bladder neck reconstruction. Review of the results of bladder neck reconstruction in all patients with a mean followup of 2.9 years (range 7 months to 13 years) demonstrates an 87 per cent satisfactory continence rate (9 of 9 boys and 4 of 6 girls). In the patients who underwent staged reconstruction the results were similar, with a 100 per cent continence rate in evaluable patients (5 of 5 boys and 2 of 2 girls). In conclusion, urethroplasty before bladder neck reconstruction in the epispadiac child with a small bladder allows an increase in capacity, thus, obviating for the most part the need for procedures such as bladder augmentation in the majority of these patients.

Child, Preschool↗
PubMed1988

Hearing impairment as a predictor of cognitive decline in dementia.

Thirty-eight patients with dementia of various etiologies were studied longitudinally to determine the change in cognition over time in subjects with and without hearing impairment. Hearing impaired subjects were older (P less than .0001), but subject groups were otherwise comparable with respect to living arrangements, medical illness, number of drugs taken, mood, years of education, and cognitive functioning at the beginning of the study period. Decline in cognitive functioning at follow-up was greater in hearing impaired subjects and this difference persisted after adjustment for the greater age of hearing impaired subjects (P less than .009). Further division of subject by diagnosis showed that only in the Alzheimer's group did hearing impairment predict more rapid cognitive decline at follow-up.

Aged↗
PubMed1988

Stimulation of neutrophil production in CSF-1-responsive clones.

The hematopoietic growth factor CSF-1 has been considered relatively lineage specific for the production of macrophages, whereas GM-CSF elicits a predominance of neutrophils. It is likely that in vivo, individual clones are stimulated by the two CSFs, although the effect of dual stimulation on progenitors and their progeny has not been completely explored. We found that in cultures initiated with low concentrations of CSF-1 or GM-CSF, alone or in combination, production of macrophages predominated. Maximally stimulatory concentrations of CSF-1 elicited a predominance of macrophages, whereas maximal GM-CSF elicited many more neutrophil/macrophage colonies and pure neutrophil colonies. A combination of maximal CSF-1 and GM-CSF elicited the same differentiation as GM-CSF alone. Delayed addition of GM-CSF to cultures initiated with CSF-1 elicited colonies indistinguishable from GM-CSF alone, suggesting that neutrophil production had been switched on by GM-CSF. In mapping studies, colonies initiated by CSF-1 increased or switched on neutrophil production when GM-CSF was added as a second stimulus. These studies show that individual clones are responsive to both CSFs, and that the differentiating influence of GM-CSF predominates over that of CSF-1. In cultures to which only CSF-1 was added, a population of progenitors was sustained that produced neutrophils only after a GM-CSF stimulus. Thus, CSF-1 may participate in maintaining a reserve of progenitors for neutrophils during periods of increased neutrophil demand.

Animals↗
PubMed1987

The effect of nafarelin acetate, a luteinizing-hormone-releasing hormone agonist, on benign prostatic hyperplasia.

We examined the influence of androgens on benign prostatic hyperplasia, using nafarelin acetate, a potent luteinizing-hormone-releasing hormone agonist, to achieve reversible androgen deprivation in men with benign prostatic hyperplasia. Nine patients with bladder-outlet obstruction due to benign prostatic hyperplasia were treated with subcutaneous nafarelin acetate (400 micrograms per day) in an open trial for six months. In all patients, serum testosterone decreased to castrate levels. Objective observations included uroflowmetry, measurement of residual urine volume, determination of prostatic size by ultrasonography, and prostatic biopsy. In all patients, the prostate regressed to a mean (+/- SEM) of 75.8 +/- 3 percent of the initial size (range, 52 to 86; P less than 0.005); the regression reached a plateau after four months. Morphologic analysis of biopsy specimens showed regression of glandular epithelium. Three of nine patients had clinical improvement with treatment. Six months after the cessation of treatment, plasma testosterone levels had returned to normal and the size of the prostate had increased to 99 +/- 5.5 percent of the initial size. These findings suggest that androgens have an important supportive role in established benign prostatic hyperplasia and that testicular suppression will benefit some patients. However, this form of treatment could be applicable only in carefully selected patients who were not surgical candidates, and it would need to be maintained indefinitely.

Aged↗
PubMed1987

Androgen receptor localization in the human prostate: demonstration of heterogeneity using a new method of steroid receptor autoradiography.

We have used a novel receptor labeling and autoradiographic technique to identify the cell types in human benign prostatic hyperplasia (BPH) that contain androgen receptors, and we have found that androgen receptor localization is heterogeneous. Prostatic androgen receptors were labeled by incubating slide-mounted frozen tissue sections (10 micron thickness) with [3H]R1881 in vitro. Tissue sections labeled in this way were subjected to concurrent biochemical and autoradiographic analysis. Some of the sections were wiped from the slides for scintillation counting to validate that the procedure indeed measures total cellular androgen receptors of appropriate high affinity and androgen steroid specificity. Replicate labeled slide-mounted tissue sections were dried rapidly, apposed to dry emulsion-coated coverslips, and exposed in the dark for autoradiography. Autoradiograms were developed, fixed, and stained; silver grains were counted over nuclei or cytoplasm of epithelium or stroma to evaluate specific androgen receptor location. Autoradiographic analysis of human glandular BPH demonstrated androgen receptor localization almost exclusively in the epithelial nuclei, with little or none in the stroma. We anticipate that data obtained using this new method of steroid receptor autoradiography may provide fresh insight into the mechanism of hormonal regulation of the prostate.

Autoradiography↗
PubMed1987

A new method for labeling and autoradiographic localization of androgen receptors.

We have used a novel receptor labeling and autoradiographic technique to localize androgen receptors in the intact rat ventral prostate at the morphological level. Frozen slide-mounted prostate tissue sections (10 micron thick) were incubated with increasing concentrations of [3H]-R1881 in the absence and presence of excess unlabeled R1881. Tissue sections labeled in this way were subjected to concurrent biochemical and autoradiographic analysis. After incubation and washing to remove free [3H]-steroid, some of the sections were wiped from the slides for scintillation counting in order to characterize and quantitate [3H]-R1881 binding. Androgen receptors could indeed be labeled in slide-mounted tissue sections, and specific [3H]-R1881 binding to these receptors was high-affinity (Kd = 1 nM), saturable, and androgen-specific. All cellular androgen receptors appear to be retained, because receptor content in sections was comparable to the sum of receptors in subcellular fractions of homogenized tissue. Replicate labeled slide-mounted tissue sections were dried rapidly, apposed to dry emulsion-coated coverslips, and exposed in the dark for autoradiography. Silver grains were counted over nuclei or cytoplasm of epithelium or stroma to evaluate specific androgen receptor location. Autoradiographic analysis demonstrated androgen receptor localization almost exclusively in the epithelial nuclei, with little or none in the stroma. We discuss here the unique features and advantages of labeling androgen receptors in slide-mounted frozen tissue sections for autoradiographic localization.

Androgens↗
PubMed1985

Blood transfusion and anesthetic practices in radical retropubic prostatectomy.

We have attempted to lessen blood transfusion requirements during radical retropubic prostatectomy. The influence of temporary occlusion of the hypogastric arteries, anesthetic techniques and autologous blood transfusions were studied in 93 men undergoing radical retropubic prostatectomy with pelvic lymph node dissection. Operations performed with the patient under general or regional anesthesia with hypogastric artery clamping required significantly less blood replacement than those performed without hypogastric artery clamping (1.8 plus or minus 0.3 versus 3.5 plus or minus 0.3 units, respectively, mean plus or minus standard error). Preoperative autologous banking of blood eliminated the need for heterologous transfusions in 10 of 15 patients in whom any autologous blood was banked (2 to 4 units per person). We conclude that temporary hypogastric artery clamping can reduce significantly the need for blood product replacement in radical retropubic prostatectomies during the perioperative period. We also are encouraging the preoperative banking of autologous blood to lessen further exposure to heterologous blood products with their attendant risks.

Adenocarcinoma↗
PubMedDate not supplied

Impaired expression of hematopoietic growth factors: a candidate mechanism for the hematopoietic defect of aging.

Aged humans and aged experimental animals exhibit a diminished ability to upregulate hematopoiesis, but the mechanism responsible for this is unknown. The purpose of the studies was to test the hypothesis that this disregulation might be attributable to altered expression of hematopoietic growth factors. We studied the in vitro ability of cells from aged humans or mice to release bioactive colony stimulating activity (CSA) and to accumulate mRNA for defined growth factors. Human light density leukocytes from the aged released less CSA than cells from the young. GM-CSF accounted for 72-100% of the CSA released by young humans, as judged by antibody inhibition studies. In contrast, GM-CSF accounted for 0-42% of CSA from aged humans. The observation of diminished expression of GM-CSF by cells from aged humans was further accompanied by a reduced accumulation of mRNA for GM-CSF. In other in vitro studies, splenic cells from aged mice released less CSA than cells from young mice, and in vivo experiments showed that splenic cells from mice challenged with E. coli accumulated less mRNA for M-CSF than young mice. These data demonstrate a similar defect in the expression of hematopoietic growth factors in aged man and mice. We propose that this diminished production of bioactive and identifiable hematopoietic growth factors may be mechanistically important in explaining the disordered hematopoiesis of aging.

Adolescent↗
PubMedDate not supplied

Box stitch modification of Hasson technique for pediatric laparoscopy.

Laparoscopy has been recognized as the modality of choice for the treatment of many diseases in urology, gynecology, and general surgery. Although laparoscopy is minimally invasive, the most frequent complications are associated with entry through the abdominal wall. The Hasson (open) technique was developed to minimize the complications by entering the abdomen under direct vision. We have modified the Hasson technique with a stitch that is easy to perform, creates a tight fascial seal, allows easy exchange of trocars, and produces an effect that is cosmetically appealing.

Child, Preschool↗