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Biomedical subjects

J H Ross

Publications and source records attributed to J H Ross.

At least 55 records · Page 3Linked to original sources
PubMed1995

Contralateral reflux after unilateral ureteral reimplantation in patients with a history of resolved contralateral reflux.

PURPOSE: We determined the risk of contralateral reflux after unilateral ureteral reimplantation in patients with a history of resolved contralateral reflux. MATERIALS AND METHODS: We reviewed our experience with 53 children who underwent unilateral ureteral reimplantation for primary vesicoureteral reflux. RESULTS: Postoperative contralateral reflux occurred in 5 of 11 children (45%) with a history of bilateral reflux that had resolved preoperatively on the contralateral side and 4 of 42 (10%) with no history of contralateral reflux. CONCLUSIONS: Strong consideration should be given to performing bilateral ureteral reimplantation in children with unilateral reflux and a history of resolved contralateral reflux.

Child, Preschool↗
PubMed1995

Patterns of metastatic spread in prepubertal yolk sac tumor of the testis.

Of the 212 patients with yolk sac tumors of the testis registered in the prepubertal testis tumor registry of the American Academy of Pediatrics, Section on Urology, we report on 33 who presented with metastatic disease. Metastases occurred to the retroperitoneum alone in 9 cases, sites consistent with hematogenous spread of disease alone in 13, sites consistent with lymphatic and hematogenous spread in 6, and sites not clearly documented in the registry in 5. These findings, which show a hematogenous predilection in the spread of metastases, suggest that retroperitoneal lymph node dissection has no routine role in the treatment of the child who presents with yolk sac tumor of the testis.

Child↗
PubMed1994

Long-term results of renal transplantation into the valve bladder.

Between 1970 and 1990 renal transplantation was performed in 16 patients with a history of posterior urethral valves. While 10 patients had undergone supravesical urinary diversion before the development of end stage renal disease, all but 1 transplant were drained to the unaugmented native bladder. The 2 and 5-year graft survival rates were 70% and 59%, respectively. Of the 15 surviving patients 11 have allografts that are functioning at a mean of 86 months after transplantation with a mean serum creatinine of 2.0 mg./dl. Urological complications occurred in 19% of the transplants. No detrimental effect of the valve bladder on long-term allograft survival or function was apparent. With appropriate treatment of vesical dysfunction, these patients can be expected to have graft function comparable to the general transplant population despite use of the unaugmented native bladder.

Adolescent↗
PubMed1993

Differential, temporal and spatial expression of genes involved in storage oil and oleosin accumulation in developing rapeseed embryos: implications for the role of oleosins and the mechanisms of oil-body formation.

The temporal and spatial expression of oleosin and delta 9-stearoyl-ACP desaturase genes and their products has been examined in developing embryos of rapeseed, Brassica napus L. var. Topas. Expression of oleosin and stearate desaturase genes was measured by in situ hybridisation at five different stages of development ranging from the torpedo stage to a mature-desiccating embryo. The temporal pattern of gene expression varied dramatically between the two classes of gene. Stearate desaturase gene expression was relatively high, even at the torpedo stage, whereas oleosin gene expression was barely detectable at this stage. By the stage of maximum embryo fresh weight, stearate desaturase gene expression had declined considerably while oleosin gene expression was at its height. In contrast to their differential temporal expression, the in situ labelling of both classes of embryo-specific gene showed similar, relatively uniform patterns of spatial expression throughout the embryo sections. Immunogold labelling of ultra-thin sections from radicle tissue with anti-oleosin antibodies showed similar patterns to sections from cotyledon tissue. However, whereas at least three oleosin isoforms were detectable on western blots of homogenates from cotyledons, only one isoform was found in radicles. This suggests that some of the oleosin isoforms may be expressed differentially in the various types of embryo tissue. The differential timing of stearate desaturase and oleosin gene expression was mirrored by similar differences in the timing of the accumulation of their ultimate products, i.e. storage oil and oleosin proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Brassica↗
PubMed1993

Testis sparing surgery for pediatric epidermoid cysts of the testis.

Epidermoid cyst of the testis is a rare, benign intratesticular tumor in children. Four patients 4 to 15 years old with epidermoid cysts were managed by tumor excision with salvage of the testis. Preoperative ultrasound, tumor marker status and intraoperative findings were suggestive of a benign neoplasm. Under these circumstances epidermoid cysts may be safely treated by excision in prepubertal patients.

Adolescent↗
PubMed1993

Risk assessments in the pesticide regulatory process.

The risk assessment process offers regulators, registrants, public interest groups and users a means of weighing apparent health effects of pesticides and other chemicals, and measuring their safety for use. This report contains the method for developing relative measures of safety for acute toxicity and expressions of risk for chronic toxicity and assesses-human exposure under a variety of extreme scenarios. Since workplace exposures usually exceed environmental exposures by two or more orders of magnitude, occupational experience with pesticides is critical to the regulatory process. Default assumptions, the adoption of conventional numbers in the absence of empirical data, for factors such as dermal absorption, metabolism, clearance and worker protective measures that seem conservative may weaken the reliability of the risk characterization process and may reduce the likelihood of recognizing significant risk. An exposure-based regulatory policy should feature measurements of absorbed dose validated using biomonitoring and margins of safety and estimates of risk that reflect human experience. This paper lists basic characteristics of unit processes of risk assessment and presents some strategies and pitfalls of the process as practiced in California in recent years.

Animals↗
PubMed1993

Characterization of a new class of oleosins suggests a male gametophyte-specific lipid storage pathway.

The expression and sequences of two related antherspecific cDNAs (I3 and C98) of Brassica napus (oilseed rape) were examined. These cDNAs were found to exhibit significant predicted amino acid sequence similarity with a group of seed-specific proteins, the oleosins, which are involved in oil body membrane structure. Pollen of B. napus also contains oil bodies, and the synthesis and accumulation of these organelles correlates with expression of the I3 and C98 transcripts. The protein content of purified pollen oil bodies was therefore examined in order to determine the presence or absence of possible oleosins. One major protein species of 14 kDa was identified and subjected to N-terminal amino acid sequence determination. The sequence of this pollen oil body associated protein is homologous to the predicted sequence of one of the anther-specific cDNs, I3, implying that this cDNA represents an anther-specific oleosin gene expressed in developing pollen. The expression of other genes active during seed oil body formation was also examined, and these were found to be specific to the sporophyte, inferring the existence of specific components of the pathway of lipid synthesis and storage in the male gametophyte. These possibilities and the relationship between different oleosin genes are discussed.

Amino Acid Sequence↗
PubMed1992

Assessing human exposures to pesticides.

Pesticide use is inevitably associated with chemical exposures that range from inferred nondetectable levels to easily measurable ones using sensitive, readily available analytical tools. Whether these exposures are of any biological significance is determined by duration, dose, and biological reactivity. The overwhelming majority of human exposures occur in a diverse chemical milieu of a nutritive substances and are of no known significance. Technologies that minimize human chemical exposures and maximize pesticide effectiveness are favored. The risk characterization process is ideally suited to assist decision makers concerning the protection of human health and evaluation of agricultural tools. It is the best means available to balance the review of pesticide impacts on health and agriculture. Regulators must be cautious to acknowledge the relative rather than absolute nature of the risk characterization process. Workplace biological monitoring must become more commonplace as a means to evaluate the chemical exposure potential of various work tasks and greater attention must be given to the biological validation of methods. Earlier needs for data to develop workplace hygiene strategies have been replaced in recent years by demands of the risk assessment process, which utilizes direct estimates of exposure and absorbed dose. Animal models, no matter how attractive, are not presently a substitute for human experience. Opportunities to gather more information on human experience associated with pesticide exposures must be more aggressively identified and pursued. Only a very small time lag should exist between identification of pesticide metabolites in rats and evaluation of metabolic similarities in humans. At the present levels of analytical sensitivity, most of our current uncertainty about the extent of worker exposure and patterns of metabolism between species can be at least clarified with the cooperation of persons who are exposed during normal day-to-day activities in the workplace. Only with better human data will the risk assessment process warrant greater reliance in decision making concerning our chemical exposures and human experience.

Environmental Exposure↗
PubMed1991

"Side table assembly"--an adjuvant to craniofacial reconstruction.

Plates and screws are used extensively in craniofacial surgery; they have increased the speed of this surgery, but this can be made even more efficient. Utilising an adjacent instrument table, the rearrangement and reassembly of bone segments resulting from osteotomy or fracture can be performed by a second surgical team using plates and screws. At the conclusion of the operation, the reassembled bony reconstruction can rapidly be placed in position with a minimum of additional screws. This technique has been found to be technically easier and to afford a considerable saving of operating time.

Bone Plates↗
PubMed1990

Influence of nephrectomy on the growth of a murine Wilms tumor: a study using parabiotic rats.

It has been reported that unilateral nephrectomy causes acceleration of the growth of a Wistar/Furth rat Wilms tumor. We studied this phenomenon in parabiotic rats by measuring tumor growth after either sham nephrectomy, or excision of 1, 2 or 3 kidneys. We observed no stimulation of tumor growth in the experimental groups. Renal function was significantly decreased after removal of 2 or 3 kidneys. Serum creatinine levels were significantly different between right and left members of parabiotic pairs in these 2 groups. The effect of unilateral and bilateral nephrectomy on tumor growth in single rats also was examined. In these rats progressive increases in tumor growth were observed after unilateral and bilateral nephrectomy. Our inability to demonstrate a tumor-stimulating factor in the parabiotic model may be due partly to incomplete sharing of humoral factors between parabionts. Serum transfer studies in vitro may prove more fruitful in demonstrating such a factor.

Animals↗
PubMed1990

Resection of nonrenal retroperitoneal tumors with large vena caval thrombi using cardiopulmonary bypass and hypothermic circulatory arrest.

Cardiopulmonary bypass with deep hypothermic circulatory arrest is a useful adjunct in the operative management of renal cell carcinoma associated with large vena caval thrombi. We present 2 patients with nonrenal retroperitoneal tumors and extensive vena caval thrombi who underwent successful surgical treatment with this method. The primary tumor was a leiomyosarcoma of the vena cava in 1 patient and a pheochromocytoma with hepatic invasion in 1. Cardiopulmonary bypass with deep hypothermic circulatory arrest is effective in decreasing the operative risk and improving the feasibility of resection in complex surgical cases. Consideration should be given to its use in a wider range of indicated procedures.

Adrenal Gland Neoplasms↗
PubMed1990

Ureterocalicostomy for reconstruction of complicated pelviureteric junction obstruction.

Seven patients with complicated pelviureteric junction (PUJ) obstruction underwent reconstruction by means of ureterocalicostomy; 5 had undergone previous surgery and 2 had primary obstruction. Radiographic studies showed resolution or improvement of the obstruction in 5 patients, who remain asymptomatic 15 to 47 months (mean 30) post-operatively. Obstruction persists in 1 patient and the other developed renal artery thrombosis with subsequent loss of the kidney. It was concluded that ureterocalicostomy can provide long-term, successful reconstruction of a complicated PUJ obstruction, but significant complications may be associated with the procedure.

Adult↗