Urinary tract infections: 2000 update.
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Diagnosis, Differential↗
Biomedical subjects
J H Ross
Publications and source records attributed to J H Ross.
Conservatism in pesticide exposure assessment.
Three important factors are commonly encountered in exposure assessment that when combined could overestimate the exposure to pesticides by as much as two orders of magnitude. The three factors discussed are dermal absorption from laboratory animal studies, daily dose extrapolated from partial day monitoring, and nonbolus dose from dermal or inhalation exposure. Conservatism built into the process by each of these three factors is substantiated with available empirical data. The dose overestimation from these factors varies discriminatively by exposure scenarios and peculiarities of a given chemical. It is for this reason that a generic overestimation factor cannot be ascribed. Following the empirical illustrations, the authors conclude that the most effective approach for dealing with the problem is to generate the most appropriate data possible. This means producing human rather than laboratory animal dermal absorption data, conducting full-day exposure monitoring studies, and whenever feasible generating dermal rather than oral toxicology data (or alternatively data on both oral and dermal pharmacokinetics) in those cases where the dermal route predominates.
Animals↗
Pheochromocytoma. Special considerations in children.
Pheochromocytoma is a rare but important tumor in children. Appropriate evaluation and management are essential for a favorable outcome. Pheochromocytomas are more often multifocal and extra-adrenal in children when compared with adults. This pattern makes the diagnosis, localization, and surgical management more challenging. Nonetheless, the standard biochemical evaluation is usually diagnostic, and MR imaging is currently the best tool for tumor localization. The possibility of a familial syndrome must always be considered and should always be thoroughly evaluated when children present with a pheochromocytoma. Conversely, children with a familial syndrome should undergo annual screening for pheochromocytoma from a young age. Given the greater likelihood of a metachronous recurrence in children, consideration should be given to adrenal-sparing surgery in selected patients. When managed appropriately, the outlook for pheochromocytoma in children is excellent. Unfortunately, the uncommon malignant tumors are still difficult to treat. Perhaps the unique genetic characteristics of pheochromocytoma will ultimately be exploited in the management of the aggressive forms of this disease.
Adrenal Gland Neoplasms↗
Needlescopic surgery for cryptorchidism: the initial series.
PURPOSE: The aim of this study is to report the initial experience with needlescopic surgery (2-mm optics and instrumentation exclusively) for the cryptorchid testicle. METHODS: Ten patients (age 8 months to 37 years) underwent 12 needlescopic procedures: orchiopexy (n = 8), orchiectomy (n = 2), and diagnostic exploration with attempted excision of testicular remnant (n = 2). Two patients underwent bilateral needlescopic orchiopexy. Needlescopic (2 mm) optics and instrumentation were used exclusively in the pediatric patients. RESULTS: All procedures were completed successfully by needlescopic techniques. Mean surgical time was 110 minutes (range, 60 to 180 minutes), and blood loss was 6 mL (range, 0 to 20 mL). There were no intraoperative complications. All procedures were performed on an outpatient basis. In all 8 orchidopexies, the testis was successfully brought to a scrotal position. CONCLUSIONS: Needlescopic techniques allow safe performance of various procedures for a cryptorchid testicle. The cosmetic result is excellent.
Adult↗
Penile adhesions after neonatal circumcision.
PURPOSE: The appropriate management of penile adhesions in circumcised boys is unclear. An important consideration is whether adhesions resolve spontaneously. We studied the incidence of penile adhesions as a function of patient age to assess the natural history. MATERIALS AND METHODS: We evaluated all circumcised boys presenting to our pediatric urology clinic. A standard form was used to classify adhesions as grade 0-no adhesions, 1-fine adhesions to the corona, 2-adhesions covering less than 50% of the glans and 3-adhesions covering greater than 50% of the glans. All boys were evaluated by 1 of 2 pediatric urologists. Previous treatment of adhesions was assessed and skin bridges were also noted. RESULTS: We enrolled in our study 254 boys 1 month to 19 years 8 months old. Only 7 patients had a history of treatment of adhesion, of whom 3 had recurrent adhesions at evaluation. Patients were divided into groups based on age, including younger than 12 months (61), 13 to 60 (78), 61 to 108 (51) and 109 months old or older (64). In these groups we noted an adhesion rate of 71%, 28%, 8% and 2%, respectively. The rate of adhesions more severe than grade 1 was 30%, 10% and 0% in boys 12 months old or younger, 13 to 60 and 61 months old or older, respectively. The oldest patient with grade 3 adhesions was 31 months old. Skin bridges in 6 cases involved the circumcision line in 4. CONCLUSIONS: Penile adhesions develop after circumcision and the incidence decreases with patient age. Although there is debate on whether to lyse these adhesions manually, our findings suggest that adhesions resolve without treatment. Based on our results we do not recommend lysing penile adhesions, except perhaps those involving the circumcision line.
Adolescent↗
Pediatric urinary tract infection and reflux.
Urinary tract infections in children are sometimes associated with vesicoureteral reflux, which can lead to renal scarring if it remains unrecognized. Since the risk of renal scarring is greatest in infants, any child who presents with a urinary tract infection prior to toilet training should be evaluated for the presence of reflux. Children who may be lost to follow-up and those who have recurrent urinary tract infections should also be evaluated. The preferred method for evaluation of urinary reflux is a voiding cystourethrogram. Documented reflux is initially treated with prophylactic antibiotics. Patients who have breakthrough infections on prophylaxis, develop new renal scarring, have high-grade reflux or cannot comply with long-term antibiotic prophylaxis should be considered for surgical correction. The preferred method of surgery is ureteral reimplantation. A newer method involves injection of the bladder trigone with collagen.
Child↗
Estimation of dermal absorption using the exponential saturation model.
Estimates of dermal absorption are used in exposure assessment to calculate the internal dose of persons contacting pesticides and are a critical part of risk assessments. An exponential saturation model with lag time was validated against a classic dermal absorption study of 12 pesticides administered to human volunteers. The model gave dermal absorption estimates consistent with reported values in the literature. Moreover, this model gave more realistic estimates of the percentage of dermal absorption for some pesticides, which have special properties. In most submitted dermal absorption studies in animals, especially rats, "bound" skin residues (BSR) at treated skin sites were generally high when animals were sacrificed more than 24 h after the dose was administered. The direct addition of the total BSR as an absorbed dose would likely overestimate actual dermal absorption. From a well-conducted dermal absorption study, this model can be utilized to estimate maximum excretion of the administered dermal dose as a result of further absorption of bioavailable BSR. Resulting dermal absorption estimates are appropriate for regulatory purposes in the risk assessment of pesticides because they take into account the bioavailability of BSR while at the same time the estimates are not overly conservative.
Animals↗
Composition and role of tapetal lipid bodies in the biogenesis of the pollen coat of Brassica napus.
The composition of the two major lipidic organelles of the tapetum of Brassica napus L. has been determined. Elaioplasts contained numerous small (0.2-0.6 micron) lipid bodies that were largely made up of sterol esters and triacylglycerols, with monogalactosyldiacylglycerol as the major polar lipid. This is the first report in any species of the presence of non-cytosolic, sterol ester-rich, lipid bodies. The elaioplast lipid bodies also contained 34- and 36-kDa proteins which were shown by N-terminal sequencing to be homologous to fibrillin and other plastid lipid-associated proteins. Tapetosomes contained mainly polyunsaturated triacylglycerols and associated phospholipids plus a diverse class of oleosin-like proteins. The pollen coat, which is derived from tapetosomes and elaioplasts, was largely made up of sterol esters and the C-terminal domains of the oleosin-like proteins, but contained virtually no galactolipids, triacylglycerols or plastid lipid-associated proteins. The sterol compositions of the elaioplast and pollen coat were almost identical, consisting of stigmasterol > campestdienol > campesterol > sitosterol >> cholesterol, which is consistent with the majority of the pollen coat lipids being derived from elaioplasts. These data demonstrate that there is substantial remodelling of both the lipid and protein components of elaioplasts and tapetosomes following their release into the anther locule from lysed tapetal cells, and that components of both organelles contribute to the formation of the lipidic coating of mature pollen grains.
Amino Acid Sequence↗
Sperm retrieval and intracytoplasmic sperm injection in patients with prune-belly syndrome.
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Adult↗
Risk of contralateral hydrocele or hernia after unilateral hydrocele repair in children.
PURPOSE: Recent laparoscopic studies indicate a high incidence of a contralateral open internal ring in children undergoing unilateral hydrocele or hernia repair, raising the question of whether routine contralateral exploration should be done. Data on the long-term risk of clinical contralateral hernia or hydrocele after unilateral hydrocele repair are limited. To address this question we performed long-term followup in patients who underwent unilateral hydrocele repair. MATERIALS AND METHODS: We followed patients who previously underwent unilateral hydrocele repair performed by one of us before 1997. Patients were interviewed by telephone and encouraged to return to one of us or their pediatrician for evaluation. RESULTS: Of the 101 patients who fulfilled study inclusion criteria 85 who were 5 to 107 months old (median age 37) at the original surgery were successfully contacted, including 45 examined by one of us or a pediatrician and 40 followed by telephone interview only. Contralateral hydrocele or hernia developed in 6 of the 89 patients (7%) 6 to 15 months (median 12) postoperatively. The remaining 79 patients have been recurrence-free for 6 to 153 months (mean 44, median 37). Of the patients 5 of 32 are (15%) and 1 of 53 (2%) who underwent left and right hydrocele repair, respectively, had contralateral recurrence. CONCLUSIONS: The risk of a clinically evident contralateral hydrocele or hernia after unilateral hydrocele repair is approximately 7%. We do not recommend routine contralateral exploration in children undergoing unilateral hydrocele repair.
Child↗
The effects of blood lactate concentration on perception of effort during graded and steady state treadmill exercise.
Studies have reported that ratings of perceived exertion (RPE) are a valid tool for exercise prescription when blood lactate concentration (BLC) is used as the intensity criterion. However, few have studied the relationship between RPE and BLC during commonly used graded exercise tests (GXTs) and simulated exercise training. The purpose of this study was to determine if the RPE: BLC relationship is transferable across GXTs and a steady state exercise trial (SST). Thirteen healthy males (25+/-5.3yrs) completed two maximal treadmill tests (Bruce and Balke protocols) followed by a SST which consisted of approximately 8 minutes of exercise at each of two intensities (approximately 40% and 70% maximal heart rate reserve). BLCs and other physiological measures were compared at matched RPEs across the GXTs and SST trial at each exercise intensity using a two-way repeated measures ANOVA. There were no significant differences in BLC at a matched RPE across the exercise trials at the lower exercise intensity with the BLCs being 1.5+/-0.3, 1.6+/-0.6 and 1.3+/-0.3 mM, respectively. However, at the higher exercise intensity BLCs were significantly lower during the Balke GXT compared to the Bruce GXT and SST (1.8+/-0.6, 2.8+/-1.8 and 3.0+/-0.8 mM, p < 0.05). These results suggest that the RPE: BLC relationship may be protocol dependent during graded exercise testing as it was only transferable from the Bruce GXT to the exercise training setting at intensities in the typical prescription range of 50-85% of VO2max.
Adult↗
Surgical considerations for patients with Wilms' tumor.
Despite the advances in multimodal treatment of Wilms' tumor, surgical staging and tumor resection remain a central component of therapy. Although standard approaches are available through multicenter studies, such as the NWTS and SIOP, controversy exists regarding several aspects of surgical management. Recent data call into question the need for contralateral exploration in the era of modern imaging. Various methods are available for managing caval tumor thrombus. Bilateral Wilms' tumor requires a special surgical strategy. The surgeon plays a key role in determining whether preoperative chemotherapy should be used to facilitate surgical resection. The role of partial nephrectomy is still being defined. And finally, surgery plays an important role in the management of tumor recurrence. Surgeons must be fully aware of the data and philosophical issues that pertain to these areas if they are to fulfill their role in the multidisciplinary team caring for children with Wilms' tumor.
Child↗
Ureteropelvic junction obstruction in children. Unique considerations for open operative intervention.
The treatment of UPJ obstruction in children should be approached in a fashion that recognizes the differences between children and adults. Radiographic definition of the urinary tract is different in children than in adults because of the size of the child and technical difficulties with instrumentation. Retrograde pyelography, in general, is not necessary in children, although this decision must be individualized. The surgical incision should be chosen based on the size of the child and the unique considerations of individual renal anatomy and pathology, as well as the surgeon's experience. In children, tubeless surgery may be performed with excellent results, however, diversion with nephrostomies and stents may be necessary in selected cases. With attention to technical details and the unique considerations in children, the results of repair of the UPJ should be excellent and reproducible.
Child↗
Ureteropelvic junction obstruction in anomalous kidneys.
UPJ obstructions occurring in anomalous kidneys require special consideration. Many anomalous kidneys are dysmorphic with extrarenal pelves, making the distinction between obstructed and nonobstructed hydronephrosis crucial. The radiographic evaluation must be thorough because there are often other associated anomalies of the ipsilateral or contralateral kidney. Operative intervention must be tailored to the specifics of the case. Although most UPJ obstructions in anomalous kidneys can be reconstructed successfully with dismembered pyeloplasty or treated with newer minimally invasive techniques, issues regarding access, operative detail, and adjunct procedures make these cases challenging for the urologic surgeon.
Adolescent↗
The absence of crossing vessels in association with ureteropelvic junction obstruction detected by prenatal ultrasonography.
PURPOSE: The widespread use of prenatal ultrasonography has led to a marked increase in the incidence of ureteropelvic junction obstruction presenting in infancy. Which of these prenatally detected lesions requires repair has yet to be fully determined. Attempts to characterize prenatally detected ureteropelvic junction obstruction in regard to symptomatic obstruction detected later in life may provide useful insights into the management of these incidentally discovered lesions. We evaluated the presence of crossing vessels in ureteropelvic junction obstruction identified by prenatal ultrasonography. MATERIALS AND METHODS: We reviewed the records of patients who underwent dismembered pyeloplasty for primary ureteropelvic junction obstruction with specific attention to the mode of presentation and presence of crossing vessels associated with obstruction. RESULTS: In 30 patients with a mean age of 6 months ureteropelvic junction obstruction detected prenatally was not associated with a crossing vessel. Ureteropelvic junction obstruction was identified postnatally in 125 patients who underwent open pyeloplasty. It was detected incidentally in 8, of whom crossing vessels were present in 1 (12%). There were signs or symptoms related to ureteropelvic junction obstruction in 117 patients. In contrast to the group with prenatally detected ureteropelvic junction obstruction in which crossing vessels were never noted, crossing vessels were associated with 36 (30%) of the 120 kidneys operated on in this postnatally discovered group. CONCLUSIONS: No crossing vessels were present in patients with prenatally detected ureteropelvic junction obstruction compared with 30% in symptomatic patients. This finding may reflect the natural history of the disorder, or it may suggest that prenatally identified ureteropelvic junction obstruction is an entity largely different from obstruction presenting later in life.
Adolescent↗
Biosynthesis, targeting and processing of oleosin-like proteins, which are major pollen coat components in Brassica napus.
The purpose of this study is to characterise the biosynthesis, targeting and processing of some of the major protein components of the pollen coat, or tryphine, of Brassica napus. The authors have N-terminally sequenced 11 of the most abundant pollen coat polypeptides, and nine of these sequences correspond to proteolytically cleaved products of seven oleosin-like genes, i.e. Oln B;1 to Oln B;6 and Oln B;11. The Oln B;11 gene product is co- or post-translationally targeted in vitro to canine microsomal membranes. This implies that the oleosin-like protein is targeted to the endoplasmic reticulum in tapetal cells in vivo. Affinity-purified antibodies raised against a 20-residue domain of Oln B;3 and B;4 gene products cross-reacted with full-length proteins of 45-48 kDa in early developing (< 2 mm to 5 mm) buds and anthers, but recognised truncated proteins of 32-38 kDa at later (4 mm to 7 mm) stages of development. The 45-48 kDa immunoreactive proteins were associated with a floating lipid body fraction obtained from a tapetal/locular fluid extract from maturing anthers and a major 48 kDa polypeptide from this fraction was confirmed by N-terminal sequencing to be a full length product of the Oln B;3 gene. Quantitative immunocytochemical studies showed that the full length 45-48 kDa oleosin-like proteins were specifically localised in the interior of tapetal cytoplasmic lipid bodies where they were associated with a regular hexagonal-like fibrous reticulum. No significant labelling of elaioplasts was observed. The same antibodies specifically labelled 32-38 kDa oleosin-like proteins on the extracellular pollen coat of maturing pollen grains. These results demonstrate for the first time that many of the major pollen coat proteins are derived from an endoproteolytic cleavage of precursor oleosin-like proteins that originally accumulate within the large cytoplasmic lipid bodies of tapetal cells.
Amino Acid Sequence↗
Primary lymphedema of the genitalia in children and adolescents.
PURPOSE: Congenital lymphedema is a rare disorder that may result in disfiguring edema of the male genitalia. We reviewed our experience with 5 cases to advance our understanding of this challenging problem. MATERIALS AND METHODS: Four boys with significant lymphedema underwent excision of the involved subcutaneous genital tissue and coverage with local skin flaps. Two boys in whom this approach failed later underwent complete excision of the involved subcutaneous tissue and skin, and coverage with split thickness skin grafts. The boy with minimal edema was observed. RESULTS: Two of the 4 boys who underwent subcutaneous genital tissue resection and coverage with local skin flaps are markedly improved, although 1 requires further revision. In the other 2 boys treatment failed, necessitating repeat genital tissue excision and grafting. While there have been no recurrences in the grafted areas, each patient has required additional operations to manage recurrent edema in adjacent tissues of the perineum and inguinal region, and in 1 significant contraction of the grafted skin developed. Mild genital lymphedema in the remaining patient has remained stable during 10 years of followup. CONCLUSIONS: Congenital lymphedema of the genitalia is a challenging problem. Recurrences requiring multiple operations are common. We recommend expectant management of mild cases. In more severe cases excision without grafting should be attempted. While skin grafting may be the most definitive solution, it does not prevent recurrence in adjacent regions, and it carries the risk of skin contraction. Skin grafts should only be used when other techniques have failed.
Adolescent↗