Selection by parasites in spate conditions in wild Trinidadian guppies (Poecilia reticulata).

Gyrodactylids are ubiquitous fish parasites and yet, with the notable exception of Gyrodactylus salaris, few studies have reported the effect of these parasites on host survival in natural populations. Here, we assess the impact of the parasite load of gyrodactylids (G. turnbulli and G. bullatarudis) on the survival and migration of guppies (Poecilia reticulata) in their natural habitat of the Aripo River in Trinidad. The recapture rate of males declined by 19% with every additional parasite, a remarkably high figure given that the parasite load in this study ranged from zero to 20 worms. In addition, with an increased number of parasites, males were more prone to be recovered downstream. In contrast, no effect of parasitism was observed in females. The mean parasite load sharply declined after a series of flushing events during heavy seasonal downpours. The parasite load varied significantly between fish depending on their location in the river, and the size of the fish explained variation in parasite load between individuals. The present study indicates that tropical gyrodactylid parasites can play an important role in the ecology of natural fish populations, causing intense bouts of natural selection in guppies during heavy rains in the wet season.

Intravesical oxybutynin chloride: experience with 42 patients.

To evaluate the efficacy of intravesical oxybutynin chloride, 42 patients who were incontinent secondary to uninhibited detrusor contractions and had failed oral anticholinergic therapy were begun on intravesical oxybutynin chloride. Indications for intravesical therapy were detrusor hyperreflexia (N = 20), detrusor instability (N = 19), and bowel/bladder overactivity after augmentation cystoplasty (N = 3). A 5-mg tablet dissolved in 30 cc of sterile water was instilled into the bladder two to three times daily via clean self intermittent catheterization. With a mean follow-up of 18.4 months, no patient reported side effects as a result of the intravesical therapy. Nine patients (21%) dropped out of the study due to inability to tolerate the catheterization or difficulty retaining the solution in the bladder. Eighteen of the 33 patients (55%) who followed the protocol experienced elimination or significant improvement of their incontinence. The results of the current study confirm the safety and usefulness of intravesical oxybutynin in treating uninhibited detrusor contractions in a difficult patient population.

Chemoattractant agents and nerve growth factor stimulate human spermatozoal reactive oxygen species generation.

OBJECTIVE: To investigate the ability of N-formyl-methionyl-leucyl-phenylalanine (f-MLP), complement 5a (C5a), and nerve growth factor (NGF) to stimulate human spermatozoal reactive oxygen species generation in fertile and infertile patients. DESIGN: Prospective, controlled study measuring human spermatozoal reactive oxygen species generation after addition of f-MLP, C5a, or NGF. SETTING: A large health maintenance organization. PATIENTS, PARTICIPANTS: The fertile group consisted of 14 men with established fertility and normal bulk semen parameters. The infertile group was comprised of 8 men who were infertile after > 18 months of unprotected sexual intercourse. INTERVENTIONS: The sperm samples were subjected to four test conditions: f-MLP stimulation, C5a stimulation, NGF stimulation, and no stimulation (control). MAIN OUTCOME MEASURE: Reactive oxygen generation was measured over a 15-minute period using the method of chemiluminescence. RESULTS: In both the fertile and infertile groups, reactive oxygen species generation was significantly enhanced by f-MLP, C5a, and NGF compared with controls. No significant difference in f-MLP- and C5a-stimulated reactive oxygen production was demonstrated between the infertile and fertile groups; however, there was a significant difference in reactive oxygen generation between infertile and fertile subjects when stimulated with NGF. CONCLUSIONS: The current study represents the first report of f-MLP-, C5a-, and NGF-stimulated reactive oxygen species generation by human spermatozoa. Nerve growth factor enhanced reactive oxygen species production to a greater extent in infertile subjects compared with fertile subjects. This points to a possible NGF-mediated biochemical defect in the sperm of infertile patients.

Nd: YAG laser treatment of extramammary Paget's disease of the penis and scrotum.

Extramammary Paget's disease is a malignant skin condition which rarely affects the penis and scrotum. Standard treatment consists of wide surgical excision in order to avoid local recurrence. A case of extensive extramammary Paget's disease of the penis and scrotum treated with the Nd:YAG laser is described. Nd:YAG laser therapy, although widely used for penile lesions, has not been previously reported for extramammary Paget's disease. Laser surgery for extramammary Paget's disease may become a useful therapeutic modality in the future because it is relatively easy to perform and allows for extension of the surgical field without excessive loss of tissue.

Contrast media reactions during voiding cystourethrography or retrograde pyelography.

Contrast media can be absorbed across the urothelium in amounts sufficient to cause severe anaphylactoid reactions. We report 2 cases of anaphylactoid reactions during voiding cystourethrography (VCUG) or retrograde pyelography (RGP). A retrospective review of 783 consecutive VCUGs or RGPs performed at our institution over the last five years revealed no other systemic contrast media reactions. Although our findings and a review of the literature discloses that the incidence appears to be extremely low, urologists and radiologists need to be aware that an anaphylactoid or vagal contrast medium reaction may develop during VCUGs or RGPs. In addition, these physicians need to be prepared to treat a reaction should one occur.

Stimulated reactive oxygen species generation in the spermatozoa of infertile men.

To investigate the possible similarities between the reactive oxygen generating systems of the leukocyte and the spermatozoa, and to identify possible biochemical differences between fertile and infertile patients, the effect of various stimulants on the production of reactive oxygen in fertile, fertile with varicocele and infertile patients was examined. Generation of reactive oxygen species by human spermatozoa was examined in 2 patient groups: a fertile group (14), which included 7 patients with a palpable varicocele, and an infertile group (16) composed of 7 patients with a palpable varicocele and 9 who remained infertile 6 months to 3 years (mean 20 months) after internal spermatic vein ligation. Various known stimulants of reactive oxygen generation in leukocytes were used to assess spermatozoal reactive oxygen production. Reactive oxygen species generation was measured by the technique of chemiluminescence. In the infertile group reactive oxygen generation was markedly increased by the calcium ionophore A23187 and the chemoattractants N-formyl-methionyl-leucyl-phenylalanine and complement 5a (p < 0.05). In addition, fertile patients with varicoceles showed significantly enhanced chemoattractant stimulated reactive oxygen generation compared to fertile donors without varicoceles. This finding of a biochemical alteration in the sperm of infertile patients and patients with varicoceles may lend support to the argument for early varicocele repair.

Stimulated release of urine histamine in interstitial cystitis.

The diagnosis of interstitial cystitis is primarily made based on clinical and cystoscopic findings with exclusion of other bladder diseases. Despite all of the efforts at definitive identification, interstitial cystitis lacks universal objective findings. Mast cell activation with associated histamine release has been postulated as an etiological factor leading to the symptom complex associated with interstitial cystitis. To investigate this hypothesis, a 3-step controlled prospective study was conducted. In step 1 reliability of urine histamine assay was critically examined, and the assay was established to be simple, reliable and valid. In step 2 random spot urine histamine levels (basal state) were measured in 25 noninterstitial cystitis and 15 interstitial cystitis patients (22.1 +/- 0.95 ng./ml. versus 19.2 +/- 1.19 ng./ml.). There was no significant difference in the random urine histamine levels between the 2 groups (p greater than 0.05). In step 3 urine histamine levels were measured before and after hydrodistention (acute stimulation) in 7 noninterstitial cystitis controls and 6 newly diagnosed interstitial cystitis patients under general anesthesia. The urine histamine-to-creatinine ratio was used to correct for the dilutional effect of normal saline used during hydrodistention. The urine histamine-to-creatinine ratios of the control group showed no significant difference before and after hydrodistention. However, the difference in the urine histamine-to-creatinine ratios of the interstitial cystitis group compared to the controls before and after hydrodistention was highly significant (p less than 0.001). Although measurement of random spot urine histamine alone (basal state) was not found useful to make the diagnosis of interstitial cystitis, measurement of urine histamine before and immediately after hydrodistention (acute stimulation) may become an important objective parameter to assist in the diagnosis of interstitial cystitis.

Mapping intravascular extension of Wilms' tumor with magnetic resonance imaging.

Accurate preoperative diagnosis of renal vein, vena caval, or intracardiac extension of Wilms' tumor allows the surgeon to better plan operative vascular control and assess the potential benefits of preoperative chemotherapy. Magnetic resonance imaging (MRI), computed tomography (CT), and ultrasound were used to study four consecutive patients presenting with Wilms' tumor. Three had vena caval involvement, with one of these having a massive right atrial tumor thrombus. A fourth patient had renal vein involvement only. We found MRI to be superior to both CT and ultrasound for mapping intravascular extension of Wilms' tumor and for delineating nonvascular disease. Because of its noninvasiveness, multiplane imaging capabilities, and image contrast and resolution, MRI is a valuable complimentary imaging modality for the diagnosis and follow-up of patients with Wilms' tumor.

Corporeal perforation or undersized prosthesis? The role of corpus cavernosum endoscopy.

At the time of revision for a unilaterally short penile prosthesis it sometimes is difficult to differentiate between an originally undersized implant and a proximal corporeal perforation. Intraoperative inspection of the corpus cavernosum with a cystoscope was performed in 2 instances and appears to be a simple diagnostic method to differentiate a proximal corporeal perforation from an undersizing of unequal corporeal bodies.

The necessity of contralateral surgical exploration in Wilms tumor with modern noninvasive imaging technique: a reassessment.

Surgical exploration of the contralateral kidney in unilateral Wilms tumor has been the standard of surgical practice. During the last decade advances in noninvasive imaging techniques (ultrasound, computerized tomography and magnetic resonance imaging) have led to more accurate definition of intrarenal pathological conditions. The intuitive question presently is whether contralateral exploration remains mandatory in Wilms tumor patients. We reviewed the records of 52 consecutive children at our institutions who underwent radiological and operative staging of the Wilms tumor from 1979 to 1988. All 48 evaluable patients underwent either preoperative computerized tomography, ultrasound and/or magnetic resonance imaging. Five bilateral Wilms tumors were diagnosed preoperatively and confirmed surgically, whereas extensive operative exploration of the contralateral kidney in the other 43 cases of radiologically diagnosed unilateral disease failed to reveal any contralateral abnormality. Thus, in all patients preoperative radiological investigation was accurate to stage the disease regarding bilaterality. With modern imaging techniques and effective chemotherapy, extensive contralateral renal exploration may no longer be mandatory to manage Wilms tumor.

The effect of inpatient psychiatric hospitalization on weight gain in children and adolescents.

Measures of weight were obtained both at admission and at discharge for children and adolescents receiving inpatient services at a private psychiatric hospital. The sample included 20 males and 20 females from each of three units: child psychiatric, adolescent psychiatric, and adolescent substance abuse. The difference between the actual weight change of the subjects and the weight change predicted from growth charts was obtained. Overall, subjects gained a significant amount of weight. The actual mean increase in weight was roughly 3.5 times greater than the predicted increase, and there were no significant differences in weight gain between males and females among patients from each of the three units. Potential explanations for this increase in weight are explored, and the implications are discussed.