Inhibition of HIV-1 infection by a CCR5-binding cyclophilin from Toxoplasma gondii

The activation of murine dendritic cells by Toxoplasma gondii has recently been shown to depend on a parasite protein that signals through the chemokine receptor CCR5. Here we demonstrate that this molecule, cyclophilin-18 (C-18), is an inhibitor of HIV-1 cell fusion and infection with cell-free virus. T gondii C-18 efficiently blocked syncytium formation between human T cells and effector cells expressing R5 but not X4 envelopes. Neither human nor Plasmodium falciparum cyclophilins possess such inhibitory activity. Importantly, C-18 protected peripheral blood leukocytes from infection with multiple HIV-1 R5 primary isolates from several clades. C-18 bound directly to human CCR5, and this interaction was partially competed by the beta-chemokine macrophage inflammatory protein 1 beta (MIP-1 beta) and by HIV-1 R5 gp120. In contrast to several other antagonists of HIV coreceptor function, C-18 mediated inhibition did not induce beta-chemokines or cause CCR5 downmodulation, suggesting direct blocking of envelope binding to the receptor. These data support the further development of C-18 derivatives as HIV-1 inhibitors for preventing HIV-1 transmission and for postexposure prophylaxis.

Modeling a Safer Smallpox Vaccination Regimen, for Human Immunodeficiency Virus Type 1–Infected Patients, in Immunocompromised Macaques

We have modeled smallpox vaccination with Dryvax (Wyeth) in rhesus macaques that had depletion of CD4(+) T cells induced by infection with simian immunodeficiency virus or simian/human immunodeficiency virus. Smallpox vaccination induced significantly larger skin lesions in immunocompromised macaques than in healthy macaques. Unexpectedly, "progressive vaccinia" was infrequent. Vaccination of immunocompromised macaques with the genetically-engineered, replication-deficient poxvirus NYVAC, before or after retrovirus infection, was safe and lessened the severity of Dryvax-induced skin lesions. Neutralizing antibodies to vaccinia were induced by NYVAC, even in macaques with severe CD4(+) T cell depletion, and their titers inversely correlated with the time to complete resolution of the skin lesions. Together, these results provide the proof of concept, in macaque models that mirror human immunodeficiency virus type 1 infection, that a prime-boost approach with a highly attenuated poxvirus followed by Dryvax increases the safety of smallpox vaccination, and they highlight the importance of neutralizing antibodies in protection against virulent poxvirus.

Development of a novel vaccinia-neutralization assay based on reporter-gene expression

In anticipation of large-scale smallpox vaccination, clinical trials of new vaccine candidates with improved safety profiles, and new vaccinia immune globulin (VIG) products, there is an immediate need to develop new assays to measure vaccinia-specific immune responses. The classical assay to measure vaccinia neutralization, the plaque-reduction neutralization test (PRNT), is slow, labor intensive, and difficult to validate and transfer. Here we describe the development of a novel vaccinia-neutralization assay based on the expression of a reporter gene, beta-galactosidase (beta-Gal). Using a previously constructed vaccinia-beta-Gal recombinant virus, vSC56, we developed a neutralization assay that is rapid, sensitive, and reproducible. The readout is automated. We show that the neutralizing titers, ID(50), for several VIG products measured by our assay were similar to those obtained by PRNTs. A new Food and Drug Administration VIG standard was established for distribution to other laboratories. The new assay will serve as an important tool both for preclinical and clinical trials of new smallpox vaccines and for evaluation of therapeutic agents to treat vaccine-associated adverse reactions.

CXCR4 heterogeneity in primary cells: possible role of ubiquitination

The chemokine receptor CXCR4 is a primary coreceptor for the HIV-1 virus. The predicted molecular weight (MW) of glycosylated CXCR4 is 45-47 kDa. However, immunoblots of whole cell lysates from human lymphocytes, monocytes, macrophages, and the Jurkat T-lymphocyte line revealed multiple MW isoforms of CXCR4. Three of the bands could be precipitated by anti-CXCR4 monoclonal antibodies (101 and 47 kDa) or coprecipitated with CD4 (62 kDa). Expression of these isoforms was enhanced by infection with a recombinant vaccinia virus encoding CXCR4. In immunoblots of two-dimensional gels, antiubiquitin antibodies reacted with the 62-kDa CXCR4 species from monocytes subsequent to coprecipitation with anti-CD4 antibodies. Culturing of monocytes and lymphocytes with lactacystin enhanced the amount of the 101-kDa CXCR4 isoform in immunoblots by three- to sevenfold. In lymphocytes, lactacystin also increased cell-surface expression of CXCR4, which correlated with enhanced fusion with HIV-1 envelope-expressing cells. Similar increases in the intensity of the 101-kDa isoform were seen after treatment with the lysosomal inhibitors monensin and ammonium chloride. Antiubiquitin antibodies reacted with multiple proteins above 62 kDa, which were precipitated with anti-CXCR4 antibodies. Our data indicate that ubiquitination may contribute to CXCR4 heterogeneity and suggest roles for proteasomes and lysosomes in the constitutive turnover of CXCR4 in primary human cells.

Dissection of human immunodeficiency virus type 1 entry with neutralizing antibodies to gp41 fusion intermediates

Human immunodeficiency virus type 1 (HIV-1) entry requires conformational changes in the transmembrane subunit (gp41) of the envelope glycoprotein (Env) involving transient fusion intermediates that contain exposed coiled-coil (prehairpin) and six-helix bundle structures. We investigated the HIV-1 entry mechanism and the potential of antibodies targeting fusion intermediates to block Env-mediated membrane fusion. Suboptimal temperature (31.5 degrees C) was used to prolong fusion intermediates as monitored by confocal microscopy. After transfer to 37 degrees C, these fusion intermediates progressed to syncytium formation with enhanced kinetics compared with effector-target (E/T) cell mixtures that were incubated only at 37 degrees C. gp41 peptides DP-178, DP-107, and IQN17 blocked fusion more efficiently (5- to 10-fold-lower 50% inhibitory dose values) when added to E/T cells at the suboptimal temperature prior to transfer to 37 degrees C. Rabbit antibodies against peptides modeling the N-heptad repeat or the six-helix bundle of gp41 blocked fusion and viral infection at 37 degrees C only if preincubated with E/T cells at the suboptimal temperature. Similar fusion inhibition was observed with human six-helix bundle-specific monoclonal antibodies. Our data demonstrate that antibodies targeting gp41 fusion intermediates are able to bind to gp41 and arrest fusion. They also indicate that six-helix bundles can form prior to fusion and that the lag time before fusion occurs may include the time needed to accumulate preformed six-helix bundles at the fusion site.

Immunoglobulin G3 from polyclonal human immunodeficiency virus (HIV) immune globulin is more potent than other subclasses in neutralizing HIV type 1

Passive antibody prophylaxis against human immunodeficiency virus type 1 (HIV-1) has been accomplished in primates, suggesting that this strategy may prove useful in humans. While antibody specificity is crucial for neutralization, other antibody characteristics, such as subclass, have not been explored. Our objective was to compare the efficiencies of immunoglobulin G (IgG) subclasses from polyclonal human HIV immune globulin (HIVIG) in the neutralization of HIV-1 strains differing in coreceptor tropism. IgG1, IgG2, and IgG3 were enriched from HIVIG by using protein A-Sepharose. All three subclasses bound major HIV-1 proteins, as shown by Western blot assay and enzyme-linked immunosorbent assay. In HIV-1 fusion assays using X4, R5, or X4R5 envelope-expressing effector cells, IgG3 more efficiently blocked fusion. In neutralization assays with cell-free viruses using X4 (LAI, IIIB), R5 (BaL), and X4R5 (DH123), a similar hierarchy of neutralization was found: IgG3 > IgG1 > IgG2. IgG3 has a longer, more flexible hinge region than the other subclasses. To test whether this is important, IgG1 and IgG3 were digested with pepsin to generate F(ab')(2) fragments or with papain to generate Fab fragments. IgG3 F(ab')(2) fragments were still more efficient in neutralization than F(ab')(2) of IgG1. However, Fab fragments of IgG3 and IgG1 demonstrated equivalent neutralization capacities and the IgG3 advantage was lost. These results suggest that the IgG3 hinge region confers enhanced HIV-neutralizing ability. Enrichment and stabilization of IgG3 may therefore lead to improved HIVIG preparations. The results of this study have implications for the improvement of passive immunization with polyclonal or monoclonal antibodies and suggest that HIV-1 vaccines which induce high-titer IgG3 responses could be advantageous.

Human peripheral blood T cells, monocytes, and macrophages secrete macrophage inflammatory proteins 1alpha and 1beta following stimulation with heat-inactivated Brucella abortus

Heat-killed Brucella abortus (HBa) has been proposed as a carrier for therapeutic vaccines for individuals with immunodeficiency, due to its abilities to induce interleukin-2 (IL-2) and gamma interferon (IFN-gamma) in both CD4(+) and CD8(+) T cells and to upregulate antigen-presenting cell functions (including IL-12 production). In the current study, we investigated the ability of HBa or lipopolysaccharide isolated from HBa (LPS-Ba) to elicit beta-chemokines, known to bind to the human immunodeficiency virus type 1 (HIV-1) coreceptor CCR5 and to block viral cell entry. It was found that human peripheral blood mononuclear cells secreted beta-chemokines following stimulation with HBa, and this effect could not be blocked by anti-IFN-gamma neutralizing antibodies. Among purified T cells, macrophage inflammatory protein 1alpha and 1beta (MIP-1alpha and MIP-1beta, respectively) secretion was observed primarily in human CD8(+) T cells. The kinetics of beta-chemokine induction in T cells were slow (3 to 4 days). The majority of beta-chemokine-producing CD8(+) T cells also produced IFN-gamma following HBa stimulation, as determined by triple-color intracellular staining. A significant number of CD8(+) T cells contained stored MIP-1beta that was released after HBa stimulation. Both HBa and LPS-Ba stimulated high levels of MIP-1alpha and MIP-1beta production in elutriated monocytes and even higher levels in macrophages. In these cells, beta-chemokine mRNA was upregulated within 30 min and proteins were secreted within 4 h of stimulation. The monocyte- and macrophage-derived beta-chemokines were sufficient to block CCR5-dependent HIV-1 envelope-mediated cell fusion. These data suggest that, in addition to the ability of HBa to elicit antigen-specific humoral and cellular immune responses, HBa-conjugated HIV-1 proteins or peptides would also generate innate chemokines with antiviral activity that could limit local viral spread during vaccination in vivo.

Management of neonatal ureteropelvic junction obstruction

No topic in urology is more contentious than the management of neonatal ureteropelvic junction obstruction. Those favoring early diagnosis and correction of obstruction in early infancy cite excellent return of function and superior surgical results compared with delayed repair. Others believe that hydronephrosis improves or resolves with growth in many instances. In the most widely quoted series, almost all such patients improved. This article attempts to separate opinion from fact. The arguments for early surgery and for observation, even when obstruction has been diagnosed, are reviewed. Several experiences with long-term surveillance are summarized.

Long-term efficacy of simple behavioral therapy for daytime wetting in children

PURPOSE

Behavioral therapy has proved benefit for children with daytime wetting but most studies have used biofeedback techniques and provide no long-term assessment of results. We previously reported similar results using simple behavioral therapy without biofeedback. We report the long-term efficacy of behavioral therapy for daytime wetting.

MATERIALS AND METHODS

Our program of behavioral therapy included timed voiding, modification of fluid intake, positive reinforcement techniques and pelvic floor (Kegel) exercises to promote pelvic floor strengthening and relaxation. Questionnaires to assess therapeutic efficacy were mailed to patients who had completed therapy more than 1 year previously.

RESULTS

A total of 48 patients responded. Mean ages at the time of the initial clinic visit and questionnaire were 8.2 and 12.9 years, respectively. Improvement in symptoms was noted in approximately 74% of the cases during the first year following therapy. At a mean of 4. 7 years after treatment 59.4% of the patients had improved daytime urinary control, 51.1% improved daytime urinary frequency and 45.6% improved daytime urinary urgency. The frequency of urinary tract infections decreased in 56.4% of the cases. Measures of psychological well-being were also noted to be improved in a majority of patients. A total of 77.3% of the patients stated that they would recommend the program to others.

CONCLUSIONS

Simple behavioral therapy without biofeedback techniques is an effective and durable first line therapy for children with daytime wetting.

Experience with transurethral incision of ureteroceles

OBJECTIVES

The value of primary transurethral ureterocele incision was investigated in the treatment of ureteroceles in infants and children.

METHODS

The charts and radiographic studies of 13 patients between the ages of 2 weeks and 8 years who underwent transurethral incision of 14 ureteroceles as primary surgical therapy at our institution were reviewed.

RESULTS

57% of the ureteroceles were intravesical and 43% extravesical. 64.3% were associated with the upper pole of a duplicated system. All 14 ureteroceles were associated with a functional renal moiety. Endoscopic incision achieved ureterocele decompression in 13 of 14 ureteroceles (93%). Preexisting hydronephrosis improved or resolved in 10 of 14 cases (71.4%). Renal function after decompression was not shown to be significantly altered or improved. 5 of 13 patients (38%) required definite surgical reconstruction for recurrent urinary tract infections, upper pole vesicoureteral reflux, hydronephrosis and lower pole vesicoureteral reflux within a mean follow-up period of 14 months.

CONCLUSION

Transurethral incision has a limited role in the treatment of ureteroceles in children. In many or even most cases it cannot be expected to constitute long-term definite treatment for ureteroceles. It is mainly indicated in patients with urosepsis, prolapsing ureteroceles with functional bladder neck obstruction or massive reflux into other renal segments. In these settings it reliably achieves decompression and allows effective treatment of infection. The function of the previously obstructed renal segment can be reevaluated at later point in time to assess whether it should be saved. The delay permits interim growth that is likely to make bladder reconstruction easier.

The incidence of nephrolithiasis in patients with spinal neural tube defects

PURPOSE

Bladder stones are common in patients with spinal neural tube defects but there are little data on the incidence of renal calculi in this population. We examined the incidence, nature and risk factors of nephrolithiasis in our clinic population of patients with neural tube defects.

MATERIALS AND METHODS

We retrospectively reviewed the charts and radiological studies of 327 patients followed at our neural tube defects clinic with routine radiological imaging of the urinary tract. Additional confirmatory studies were performed when stones were noted.

RESULTS

Renal calculi were identified in 20 patients with neural tube defects (6.1%). The incidence of nephrolithiasis increased with age. Renal stones were noted in 19 patients (10.7%) 12 years old or older. Management of the stones in these patients resulted in overall 53% stone-free and 87% recurrence rates after intervention. Major risk factors for new and/or recurrent renal stone formation were bacteriuria in 95% of the cases, lower urinary tract reconstruction in 80%, pelvicalicectasis in 70%, vesicoureteral reflux in 65%, a thoracic level spinal defect in 60% and renal scarring in 55%.

CONCLUSIONS

These data suggest that there is a higher incidence of nephrolithiasis in patients with neural tube defects than in the general population and the risk of stone recurrence is also elevated. Most patients with stones had undergone lower urinary tract reconstruction. Other risk factors were bacteriuria, pelvicalicectasis, vesicoureteral reflux and a thoracic level neural tube defect.

The incidence of nephrolithiasis in patients with spinal neural tube defects

PURPOSE

Bladder stones are common in patients with spinal neural tube defects but there are little data on the incidence of renal calculi in this population. We examined the incidence, nature and risk factors of nephrolithiasis in our clinic population of patients with neural tube defects.

MATERIALS AND METHODS

We retrospectively reviewed the charts and radiological studies of 327 patients followed at our neural tube defects clinic with routine radiological imaging of the urinary tract. Additional confirmatory studies were performed when stones were noted.

RESULTS

Renal calculi were identified in 20 patients with neural tube defects (6.1%). The incidence of nephrolithiasis increased with age. Renal stones were noted in 19 patients (10.7%) 12 years old or older. Management of the stones in these patients resulted in overall 53% stone-free and 87% recurrence rates after intervention. Major risk factors for new and/or recurrent renal stone formation were bacteriuria in 95% of the cases, lower urinary tract reconstruction in 80%, pelvicalicectasis in 70%, vesicoureteral reflux in 65%, a thoracic level spinal defect in 60% and renal scarring in 55%.

CONCLUSIONS

These data suggest that there is a higher incidence of nephrolithiasis in patients with neural tube defects than in the general population and the risk of stone recurrence is also elevated. Most patients with stones had undergone lower urinary tract reconstruction. Other risk factors were bacteriuria, pelvicalicectasis, vesicoureteral reflux and a thoracic level neural tube defect.

Orchiopexy for impalpable testis: high spermatic vessel division is a safe maneuver

PURPOSE

This review was performed to assess the effect of protecting the collateral circulation between spermatic and vasal vessels by leaving a strip of peritoneum attached to the lower spermatic cord in patients in whom the spermatic vessels needed to be divided to bring the testis into good scrotal position.

MATERIALS AND METHODS

Between 1983 and 1994, 22 boys were encountered in whom 1 testis was always normal in size and position, and the other was intra-abdominal and would not be in normal scrotal position after complete cord straightening. A strip of peritoneum had been left attached to the spermatic cord before full mobilization. After high division of the spermatic vessels the testes were brought in the mid scrotum during the same operation.

RESULTS

All testes remained in scrotal position except 1 which retracted and was subsequently removed. None became atrophic.

CONCLUSIONS

Division of the spermatic vessels, the Fowler-Stephens maneuver, can safely be performed during an initial operation as long as its possible need is anticipated, and the collateral circulation between the vasal vessels and spermatics is not disrupted. Secondary orchiopexy for inadequate cord length is now rarely required. This type of open orchiopexy for high impalpable testis is safe, is easy to learn, has no increased morbidity and is generally less expensive than a laparoscopic approach.

Sonographic appearance of the bladder after endoscopic incision of ureteroceles

OBJECTIVE

Our intent was to describe the range of postoperative sonographic appearances of the bladder after endoscopic incision of ureteroceles.

CONCLUSION

Preoperative and postoperative sonographic examinations of the bladder were reviewed in 14 patients (15 ureteroceles) who underwent endoscopic ureterocele incision. Five different appearances of the ureterovesical junction after endoscopic incision were found: a pseudomass (5/15), focal mucosal thickening (3/15), residual ureterocele with decrease in size (3/15), persistent unchanged ureterocele (1/15), and no residual abnormality (3/15). The most common postoperative sonographic appearance associated with development of vesicoureteral reflux was a mucosal pseudomass (4/6). The other bladder sonographic appearances had no correlation with development of reflux, degree of hydronephrosis, or success of the surgery.

Renal ultrasound changes after pyeloplasty in children with ureteropelvic junction obstruction: long-term outcome in 47 renal units

PURPOSE

We evaluated the use of renal ultrasound for monitoring pyelocaliectasis after pyeloplasty in children.

MATERIALS AND METHODS

Changes in pyelocaliceal dilatation following pyeloplasty were assessed by serial ultrasound. Of 104 children 0 to 12 years old who underwent pyeloplasty between 1982 and 1992, 44 (47 renal units) were monitored with serial ultrasound for at least 2 years (range 2 to 9, mean 3.8). Patient ages at pyeloplasty were 0 to 3 months (17), 4 to 12 months (8), 1 to 6 years (13) and 7 to 12 years (6). Preoperative and postoperative ultrasound was reviewed by a single pediatric radiologist blinded to the date of surgery. The degree of pyelocaliectasis was graded as 0 to 4 according to the classification of the Society for Fetal Urology.

RESULTS

Preoperative ultrasound revealed grade 4 pyelocaliectasis in 26 kidneys (55%) and grade 3 disease in 21 (45%). Grade was the same or worse 1 month after pyeloplasty in the majority of kidneys (92%) studied at this interval. Of the 47 renal units assessed 43 (91%) showed improvement in pyelocaliectasis during postoperative followup. Only 38% of the kidneys improved during the first 6 months of followup, while 81% were improved 2 years postoperatively. Improvement to grade 0 or 1 dilatation occurred in only 9 kidneys (19%). The rate of resolution of pyelocaliectasis was not related to preoperative grade or patient age at pyeloplasty.

CONCLUSIONS

Improvement on renal ultrasound after pyeloplasty appears to be gradual. Less than half of the patients had improvement in the initial 6 months after pyeloplasty and pyelocaliectasis rarely resolved completely. While renal ultrasound can provide an accurate and cost-effective means of monitoring children on a long-term basis after pyeloplasty, sonographic evaluation in the early postoperative period commonly shows increased or unchanged pyelocaliectasis.

A new approach to the closure of cloacal exstrophy

Cloacal exstrophy patients are often difficult to reconstruct. Urinary continence is usually achievable only with a catheterizable stoma of some type. Since cloacal exstrophy is usually associated with omphalocele or gastroschisis, one-stage closure of the abdominal wall defect is frequently impossible. We prefer to incorporate the exstrophic large bowel, which separates the hemibladders, into the closed bladder as a sort of "natural" augmentation to maximize its volume for use as a continent reservoir. If a silastic "silo" or synthetic mesh is required to close the abdominal wall, excessive scarring occurs and later creation of a continent stoma is usually difficult and time-consuming. In all but those with the smallest abdominal wall defects we recommend that the omphalocele and upper abdominal wall be repaired first, replacing the evicted gut into the peritoneal cavity. During nutritional stabilization a tissue expander is placed under the superficial musculature of the chest wall. The flap is enlarged by gradual inflation of the tissue expander until it fills the abdominal wall defect left by subsequent closure of the cloacal exstrophy. The flap is then rotated inferiorly with blood supply intact at the time of bladder closure to make good the remaining abdominal wall defect. This flap improves the appearance of the abdominal wall and reduces scarring. Thus, this approach has the possibility of making subsequent operations to provide continence shorter, simpler, and more successful in most infants with cloacal exstrophy.

Pediatric urology manpower report 1995. Ellen Shapiro on behalf of the American Association of Pediatric Urologists

PURPOSE

The quality and efficiency of any health care system depend on an appropriate level of manpower. The manpower issues of tomorrow will be influenced by the number of physicians and specialists trained today. The objectives of this manpower survey of pediatric urologists in the United States were to determine anticipated manpower requirements and provide caveats related to the practice of pediatric urology.

MATERIALS AND METHODS

A manpower questionnaire was distributed to pediatric urologists at the American Urological Association meeting in Las Vegas, Nevada in April 1995. Of the 234 distributed questionnaires 204 (87%) were completed and entered into a computer program.

RESULTS

Of responding pediatric urologists 70% were younger than 50 years, 81% practiced full-time pediatric urology and 45% were university based. The rates of respondents indicating that their present workload was too busy, appropriate or not busy enough were 10, 70 and 20%, respectively. A total of 71% of respondents indicated that they would discourage a newly trained individual from setting up a practice in their area. Of practicing pediatric urologists 26% intended to retire within the next 10 years. In April 1995, 80 respondents (39%) representing 67 practices were considering adding an associate within the next 10 years. By the end of 1995 only 56 practices will remain that will add an associate within the next 10 years. A total of 82% of respondents believed that there was an excess number of pediatric urology training programs.

CONCLUSIONS

The pediatric urology community presently trains 10 to 15 pediatric fellows per year. Based on the 1995 manpower survey, if this trend continues an excess of 40 to 90 pediatric urologists will be trained in the next 10 years. The conclusion that there is an overabundance of pediatric urologists in training is supported by the general consensus of practicing pediatric urologists. Policies related to the training of pediatric urology fellows and urology residents should depend, not on the manpower needs at individual medical centers, but on the collective needs of our specialty and the patients whom we serve.

Use of the expanded thoracoepigastric myocutaneous flap in the closure of cloacal exstrophy

We describe the first reported use of an expanded thoracoepigastric myocutaneous flap in the closure of cloacal exstrophy. This approach offers several distinct advantages. The expander increases the available cutaneous surface area of the thoracoepigastric region, improves vascularity, induces a fibrous capsule that augments the abdominal wall, permits primary closure, and avoids prosthetic adjuncts that increase scarring and hinder delayed urinary tract reconstruction. Osteotomy and spica casting may be obviated by using this flap, but mesh may be required eventually. We anticipate its use in all future cases in which the abdomen cannot be closed safely at the primary procedure at this institution. This technique also should be considered for classic bladder exstrophy or any other large congenital or acquired defect of the lower abdomen.

Are modern imaging techniques over diagnosing ureteropelvic junction obstruction?

Since the widespread use of real-time ultrasonography in the early 1980s, ureteropelvic junction obstruction has been diagnosed at earlier ages and prenatally on a presumptive basis. However, substantial controversy exists over the diagnosis and treatment of ureteropelvic junction obstruction. We conducted an epidemiological study to determine if modern imaging techniques are leading to the over diagnosis of ureteropelvic junction obstruction. Records were collected retrospectively from 3 hospitals serving 2 adjacent counties to determine the number of pyeloplasties performed in 1970 to 1992. The 2 university hospitals and 1 large private hospital provide a wide variety of services and choice of urologists, and so it was assumed that most patients requiring pyeloplasty in the area would be captured. Of the 555 pyeloplasties 240 (43%) were performed on children 12 years old or younger. Logistic regression analysis revealed an overall increase of pyeloplasties per year of 56.8% in 23 years, which was not markedly different from the population growth in the area in the same period (49.3%). A statistically significant increase in the number of pyeloplasties performed in the first year of life was noted. This trend appeared to begin in 1981: 8 pyeloplasties were performed in the first year of life between 1970 and 1980 compared to 91 between 1981 and 1992. Pyeloplasties in children 1 to 6 years old increased with time at a much lower rate that was not statistically significant and the number of pyeloplasties decreased in those 7 to 12 years old. Therefore, it appears that modern imaging techniques are not leading to an over diagnosis of ureteropelvic junction obstruction but to detection of the disease at an earlier age.

Acute pancreatitis in children: CT findings of intra- and extrapancreatic fluid collections

PURPOSE

To determine the location and importance of fluid collections in children with acute pancreatitis.

MATERIALS AND METHODS

The authors retrospectively reviewed the abdominal computed tomographic (CT) scans of 28 children with acute pancreatitis. CT scans were evaluated for pancreatic size and distribution of intra- and extrapancreatic fluid collections. Extrapancreatic fluid was classified as (a) peritoneal, (b) retroperitoneal, (c) mesenteric, or (d) ligamentous.

RESULTS

Fourteen children (50%) had complicated pancreatitis associated with fluid collections. Intrapancreatic fluid was identified in only two patients (7%), whereas extrapancreatic fluid was seen in 14 (50%). Extrapancreatic fluid was most often seen in the anterior pararenal space, followed by the lesser sac, lesser omentum, and transverse mesocolon. The fluid collections diminished spontaneously in 11 patients (78%). Three patients with persistent fluid collections required surgical intervention for associated abnormalities.

CONCLUSION

Intrapancreatic fluid collections are rare in children with pancreatitis. Extrapancreatic fluid collections tend to be extensive, but most diminish spontaneously.