Biomedical subjects
J H Ross
Publications and source records attributed to J H Ross.
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.
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.
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.
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.
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.
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.
Management of bilateral Wilms' tumors in the daughter of Jehovah's Witnesses.
Surgical treatment of the children of Jehovah's Witnesses is a challenging problem both ethically and technically. The authors recently operated on such a child who had bilateral Wilms' tumors. Techniques used to minimize blood loss included erythropoietin, hemodilution, and the argon beam coagulator. A full understanding of the religious, legal, and ethical issues is essential when treating the children of Jehovah's Witnesses.
Use of a de-epithelialized local skin flap in hypospadias repairs accomplished by tubularization of the incised urethral plate.
OBJECTIVES: Snodgrass recently described a form of urethral tubularization with longitudinal incision of the urethral plate to create an elliptical meatus. To prevent fistulae, a transverse island of dorsal subcutaneous tissue was used to cover the repair. The generation of this flap may compromise blood supply to the skin that is used in the skin closure, and predispose to penile torsion. We have modified the technique to address these concerns, while accomplishing the major goal of functional success-particularly minimizing or eliminating fistulae. METHODS: Eighteen boys, aged 6 months to 6 years, with distal or midshaft hypospadias, underwent a one-stage repair using a modification of Snodgrass' technique. Rather than a transverse island flap of subcutaneous tissue, a local de-epithelialized skin flap was used to cover the urethroplasty. RESULTS: Sixteen patients have returned for follow-up, and all patients have an excellent cosmetic and functional result with an elliptical glanular meatus. There have been no cases of fistula or meatal stenosis. CONCLUSIONS: Distal hypospadias repair utilizing a de-epithelialized local skin flap to cover a tubularized incised urethral plate gives an excellent cosmetic and functional result. Optimal blood supply to the ultimate skin coverage is preserved, and penile torsion is avoided.
Promoter sequences from two different Brassica napus tapetal oleosin-like genes direct tapetal expression of beta-glucuronidase in transgenic Brassica plants.
To investigate the sequences responsible for the regulated expression of tapetal-specific oleosin-like genes, ca. 2 kb of the 5'-upstream regions from two divergent genes, OlnB;4 and OlnB;13, were isolated, sequenced and fused to the reporter gene beta-glucuronidase for study in transgenic Brassica napus plants. Although the proteins encoded by these two genes are highly divergent, except for the conserved oleosin-like domain, the first 250 bp of their 5'-upstream regions was 86% identical, including a region of 150 bp upstream from the TATA box. Analysis of 42 independent transformants by histochemical and fluorometric methods showed that both promoters directed tapetal-specific expression that peaked at the 4 mm flower bud stage.
Intra- and extracellular lipid composition and associated gene expression patterns during pollen development in Brassica napus.
Pollen development in angiosperms is regulated by the interaction of products contributed by both the gametophytic (haploid) and sporophytic (diploid) genomes. In entomophilous species, lipids are major products of both sporophytic and gametophytic metabolism during pollen development. Mature pollen grains of Brassica napus are shown to contain three major acyl lipid pools as follows: (i) the extracellular tryphine mainly consisting of medium-chain neutral esters; (ii) the intracellular membranes, particularly endoplasmic reticulum, mainly containing phospholipids; and (iii) the intracellular storage lipids, which are mostly triacylglycerols. This paper reports on the kinetics of accumulation of these lipid classes during pollen maturation and the expression patterns of several lipid biosynthetic genes and their protein products that are differentially regulated in developing microspores/ pollen grains (gametophyte) and tapetal cells (sporophyte) of B. napus. Detailed analysis of three members of the stearoyl-ACP desaturase (sad) gene family by Northern blotting, in situ hybridization and RT-PCR showed that the same individual genes were expressed both in gametophytic and sporophytic tissues, although under different temporal regulation. In the tapetum, maximal expression of two marker genes for lipid biosynthesis (sad and ear) occurred at a bud length of 2-3 mm, and the corresponding gene products SAD and EAR were detected by Western blotting in 3-4 mm buds, coinciding with the maximal rates of tapetal lipid accumulation. These lipids are released following tapetal cell disintegration and are relocated to form the major structural component of the extracellular tryphine layer that coats the mature pollen grain. In contrast, in developing microspores/pollen grains, maximal expression of the lipid marker genes sad, ear, acp and cyb5 was at the 3-5 mm bud stages, with the SAD and EAR gene products detected in 4-7 mm buds. This pattern of expression coincided with accumulation of the intracellular storage and membrane lipid components of pollen. These results suggest that, although the same genes may be expressed in the sporophytic tapetal cells and in gametophytic tissues, they are regulated differentially leading to the production of the various contrasting lipidic structures that are assembled together to give rise to a viable, fertile pollen grain.
Expression and subcellular targeting of a soybean oleosin in transgenic rapeseed. Implications for the mechanism of oil-body formation in seeds.
Two genomic clones, encoding isoforms A and B of the 24 kDa soybean oleosin and containing 5 kbp and 1 kbp, respectively, of promoter sequence, were inserted separately into rapeseed plants. T2 seeds from five independent transgenic lines, three expressing isoform A and two expressing isoform B, each containing one or two copies of the transgene, were analysed in detail. In all five lines, the soybean transgenes exhibited the same patterns of mRNA and protein accumulation as the resident rapeseed oleosins, i.e. their expression was absolutely seed-specific and peaked at the mid-late stages of cotyledon development. The 24 kDa soybean oleosin was targeted to and stably integrated into oil bodies, despite the absence of a soybean partner isoform. The soybean protein accumulated in young embryos mainly as a 23 kDa polypeptide, whereas a 24 kDa protein predominated later in development. The ratio of rapeseed:soybean oleosin in the transgenic plants was about 5:1 to 6:1, as determined by SDS-PAGE and densitometry. Accumulation of these relatively high levels of soybean oleosin protein did not affect the amount of endogenous rapeseed oleosin. Immunoblotting studies showed that about 95% of the recombinant soybean 24 kDa oleosin (and the endogenous 19 kDa rapeseed oleosin) was targeted to oil bodies, with the remainder associated with the microsomal fraction. Sucrose density-gradient centrifugation showed that the oleosins were associated with a membrane fraction of buoyant density 1.10-1.14 g ml-1, which partially overlapped with several endoplasmic reticulum (ER) markers. Unlike oleosins associated with oil bodies, none of the membrane-associated oleosins could be immunoprecipitated in the presence of protein A-Sepharose, indicating a possible conformational difference between the two pools of oleosin. Complementary electron microscopy-immunocytochemical studies of transgenic rapeseed revealed that all oil bodies examined could be labelled with both the soybean or rapeseed anti-oleosin antibodies, indicating that each oil body contained a mixed population of soybean and rapeseed oleosins. A small but significant proportion of both soybean and rapeseed oleosins was located on ER membranes in the vicinity of oil bodies, but none were detected on the bulk ER cisternae. This is the first report of apparent targeting of oleosins via ER to oil bodies in vivo and of possible associated conformational/processing changes in the protein. Although oil-body formation per se can occur independently of oleosins, it is proposed that the relative net amounts of oleosin and oil accumulated during the course of seed development are a major determinant of oil-body size in desiccation-tolerant seeds.
Epidemiological features of testicular teratoma in a prepubertal population.
PURPOSE: Prepubertal teratomas of the testis are rare benign tumors. Knowledge of the epidemiology of testicular teratomas and associated alpha-fetoprotein (AFP) levels could assist in planning treatment for prepubertal patients suspected of having teratoma of the testis. MATERIALS AND METHODS: We evaluated data on testicular teratoma from the Prepubertal Testis Tumor Registry of the Section on Urology of the American Academy of Pediatrics. RESULTS: Median patient age at presentation was 13 months. Teratomas occurred equally in the right and left testes. Most patients presented with a scrotal mass. Preoperative AFP levels were elevated in 20 of the 34 patients and postoperative levels were elevated in 9 of 10. Most patients were treated with radical orchiectomy and no metastatic disease was reported. CONCLUSIONS: Data in the registry confirm the benign nature of this tumor. Normal AFP levels should not be expected in infants with teratoma.
Characterization of anther-expressed genes encoding a major class of extracellular oleosin-like proteins in the pollen coat of Brassicaceae.
A large, heterogeneous, highly expressed gene family encoding oleosin-like proteins is described in the Brassicaceae. Seven related cDNA sequences were isolated from Brassica napus anther mRNA using RACE-PCR and compared with other recently described anther-specific oleosin-like genes from B. napus. The expression patterns of four representative members of this diverse gene family were analyzed by Northern blotting and in situ hybridization. In all cases, the genes were expressed specifically in the tapetum of 3-5 mm B. napus buds, which contained microspores at the late-vacuolate and bicellular stages of development. The predicted protein products are ordered into subclasses, each of which has a characteristic C-terminal domain, containing different amino acid motifs or repeated residues. Tryphine (pollen coat) fractions from mature B. napus pollen were found to be particularly enriched in polypeptides of apparent molecular weights 32-38 kDa, plus numerous less abundant polypeptides of less than 15 kDa. The N-terminal 15-20 residues of three of these polypeptides (12, 32 and 38 kDa) were found by microsequencing to be identical to parts of the predicted amino acid sequences of three of the tapetal-expressed oleosin-like genes. This indicates the possibility of post-translational modification of these proteins resulting in a cleavage of the primary translation products in order to generate the mature tryphine polypeptides. These data imply that a large and diverse group of oleosin-like proteins is synthesized in the tapetum of B. napus anthers and that following tapetal degradation, these proteins, possibly in modified form, then relocate to the developing microspores where they eventually constitute some of the major components of the extracellular tryphine of mature pollen grains. These proteins share a conserved 70 amino acid residue hydrophobic domain and are related structurally to the seed-specific intracellular oleosins, although their biological function may be different.
Henry Graves Bull (1818-1885): a provincial polymath.
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An unusual pelvic pseudotumor: a case report.
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Surgical considerations to preserve renal function in children with chronic renal failure.
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Diagnostic tunica vaginoscopy in a rodent model of testicular torsion.
OBJECTIVES: To evaluate the effectiveness of percutaneous endoscopy of the tunica vaginalis for identifying testicular torsion in a rodent model. METHODS: One testis was randomly selected in 10 Wistar rats weighing 500 to 600 g. Following 2 hours of 720 degree torsion, bilateral percutaneous endoscopy of the tunica vaginalis was performed by a blinded investigator utilizing a 70 degree cystoscope lens through a single midline 3 to 4 mm scrotal cutdown incision. RESULTS: Using this technique, the blinded investigator was able to identify the torsed testis rapidly in every case, which was distinguished by its cyanotic color and by the size and color of the testicular surface vessels. CONCLUSIONS: Tunica vaginoscopy is a simple, accurate, rapidly performed, minimally invasive, diagnostic technique in this experimental model of testicular torsion.