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Biomedical subjects

A D Smith

Publications and source records attributed to A D Smith.

At least 199 records · Page 11Linked to original sources
PubMed1995

Urolume endourethral prosthesis for the treatment of urethral stricture disease: long-term results of the North American Multicenter UroLume Trial.

OBJECTIVES: To evaluate the long-term results of the UroLume endourethral prosthesis for the treatment of recurrent bulbar urethral strictures. METHODS: In a multicenter, prospective study 175 patients with recurrent bulbar urethral strictures were enrolled in a Food and Drug Administration (FDA) trial of the UroLume endourethral prosthesis. One hundred thirty-nine patients were available for follow-up at 1 year, and 81 patients were available for follow-up at 2 years. RESULTS: Clinically and statistically significant results were seen at 1 year and sustained at 2 years. Re-treatment rate was down from 75.2% preinsertion to 14.3% 1 year postinsertion of the prosthesis. Explantation was required in only 3% of patients. CONCLUSIONS: Based on these and European data, the UroLume endourethral prosthesis offers a significant advantage over the currently available treatments for recurrent bulbar urethral strictures.

Adolescent↗
PubMed1995

Model of human transitional cell carcinoma: tumor xenografts in upper urinary tract of nude rat.

An in vivo model for the study of human transitional cell carcinoma (TCC) in the urinary tract is desirable. Orthotopic xenografts are useful in order to approximate better the behavior of human tumor cells in situ. Prior models have been described in the urinary bladder of the nude mouse and rat. We have developed the first model of implantation of human TCC in the upper urinary tract of an experimental animal. The kidneys of homozygous nude rats 4 weeks of age were inoculated with 1-5 x 10(6) cells of the RT4 well-differentiated papillary human TCC line through bilateral flank incisions, with transparenchymal injection of tumor cells into either the collecting system (renal pelvis) or the parenchyma. The overall implantation rate was 92% (54/59 kidneys). However, implantation into the collecting system occurred in only 45% (18/45) of the group. Ligation of the ureter prior to inoculation to produce urine stasis improved the mucosal implantation rate. Despite suspect urine cytology findings in the renal pelvis injection group, no distal seeding of the urinary tract was seen. Intraparenchymal tumor growth was less differentiated and had a higher fraction of mitotic cells than mucosal tumors. Vascular and lymphatic invasion were commonly seen; however, distant metastasis was not observed. This model will prove useful in determining the role of seeding in recurrent disease and in developing less invasive modalities for the treatment of upper tract TCC.

Animals↗
PubMed1995

Endoscope modifications for laser prostatectomy.

Prior to the development of the technique of laser prostatectomy, contemporary modifications to resectoscope design for transurethral prostatectomy had been scant. With the introduction of laser prostatectomy and the characterization of the "mini-TURP" technique, a new demand for improved continuous-flow cystoscopes and resectoscopes has developed. The ideal cystoscope design for laser prostatectomy would require the following: (1) continuous irrigant flow for optimum cooling of the laser element; (2) a large inflow port so that flow is not impaired by the presence of the fiber in the working channel; (3) a large outflow port to maximize irrigant flow; and (4) a fiber stabilizer to enable easy manipulation of the fiber in the center of the viewing field. The ideal resectoscope design for laser prostatectomy would require the following: (1) continuous flow of irrigant for cooling of the laser fiber; (2) stabilization of the laser fiber in the center of the field of view; (3) the ability to interchange electrocautery loops with laser fibers without changing the sheath; and (4) the ability to apply laser energy to tissue with the same Iglesias action used in transurethral resection of the prostate (TURP). This review analyzes the features of the new continuous-flow cystoscopes and resectoscopes manufactured specifically for use in laser prostatectomy. All manufacturers were requested to submit their most up-to-date literature and photographs of the specific instruments they manufacture. The technical specifications, advantages, and disadvantages of each instrument are discussed.

Cystoscopes↗
PubMed1995

Laparoscopic transperitoneal bladder diverticulectomy: surgical technique.

A large bladder diverticulum causing poor emptying in an 84-year-old man was removed laparoscopically in a 6.5-h operation. The patient was discharged from the hospital on the third postoperative day, having had minimal analgesic requirements. A Council catheter and stylet in the diverticulum greatly facilitated identification of the sac with the laparoscope. Difficulties with intracorporeal knot tying were avoided by using the Lapra-Ty system. Experienced laparoscopic surgeons may find this method of diverticulectomy valuable. With experience, the operating time should be reduced.

Adenocarcinoma↗
PubMed1995

Matrix modulates uptake of calcium oxalate crystals and cell growth of renal epithelial cells.

Handling of urinary crystals by renal epithelial and medullary interstitial cells may play an important role in the pathogenesis of renal stones and associated renal scarring. We examined the effects of calcium oxalate monohydrate (CaOM) crystals on the proliferative activity of renal tubular cells (opossum kidney) and renal medullary interstitial cells in culture. We also studied the impact of altered extracellular matrix on cell proliferation as well as on uptake of crystals by epithelial cells. Epithelial cells incubated with CaOM showed greater (p < 0.05) growth when compared with untreated cells (control, 10.5 +/- 1.1 versus CaOM, 16.6 +/- 1.6 x 10(6) cells per dish). the CaOM crystal-cell interaction also enhanced proliferation of interstitial cells (at 48 hours, control, 3.3 +/- 0.2 versus CaOM, 4.2 +/- 0.1 x 10(6) cells per dish, p < 0.02; at 72 hours, control, 3.6 +/- 0.3 versus 5.5 +/- 0.4 x 10(6) cells per dish, p < 0.01). Collagen, a constituent of extracellular matrix, inhibited (p < 0.01) proliferation of epithelial cells. Semiconfluent epithelial cells grown on collagen gels showed greater (p < 0.01) uptake of 45CaOM crystals when compared with uptake by cells grown on either uncoated (control) or albumin-coated plastic dishes (control, 979.9 +/- 51.1, albumin, 876.4 +/- 28.3, collagen gel, 1502.5 +/- 103.8 cpm per well). Epithelial cells grown to confluence on collagen gels also showed enhanced (p < 0.05) uptake of 45CaOM crystals. Reflectance microscopy as well as ultrastructural studies revealed intracellular localization of CaOM crystals. These results indicate that CaOM crystals stimulate the growth of both epithelial and interstitial cells. Enhanced growth of interstitial cells may also lead to increased synthesis of extracellular matrix. The latter may further modulate crystal uptake as well as cell growth of adjacent epithelial cells. These findings may be important in the development of nephrolithiasis and associated interstitial scarring.

Animals↗
PubMed1995

Chimeras from a human rhinovirus 14-human immunodeficiency virus type 1 (HIV-1) V3 loop seroprevalence library induce neutralizing responses against HIV-1.

A chimeric virus library was designed whereby sequences corresponding to the V3 loop of human immunodeficiency virus type 1 (HIV-1) were presented on the surface of human rhinovirus 14. The V3 loop sequences consisted of a relatively conserved segment of seven amino acids and five adjacent residues that were allowed to vary in proportion to their seroprevalence among HIV-1 isolates of North America and Europe. A technique called random systematic mutagenesis was used to incorporate the composite V3 loop sequences flanked by zero to two randomized amino acids. This library could contain 2.7 x 10(8) members having diverse sequences and conformations. Immunoselection of a portion of this library by using two neutralizing V3 loop-directed monoclonal antibodies followed by selection for desirable growth and purification characteristics yielded a set of chimeric rhinoviruses, five of which are described. The inserted sequences in the five chimeras do not match those of any known isolate of HIV-1. Nonetheless, all five chimeras were neutralized by antibodies directed against different strains of HIV-1 and were able to elicit the production of antibodies that bind V3 loop peptides from diverse HIV-1 isolates. Moreover, antisera derived from four of the five chimeras were capable of neutralizing one or more strains of HIV-1 in cell culture. This study demonstrates that random systematic mutagenesis in conjunction with antibody screening is a powerful and efficient means to obtain antigenic chimeras with relevant immunogenic properties.

Amino Acid Sequence↗
PubMed1995

Knee injuries in young athletes.

The differential diagnosis of children's knee injuries includes not only the typical adult injuries to bone, ligament, and cartilage, but also growth plate injuries. Bony contours are not as well defined in children due to incomplete ossification, and the practitioner must look for certain types of injuries based on the history and the physical findings because radiographic signs may be difficult or impossible to see.

Adolescent↗
PubMed1995

Percutaneous management of transitional cell carcinoma of the renal collecting system: 9-year experience.

PURPOSE: We establish the effectiveness of percutaneous resection of transitional cell carcinomas of the renal collecting system. MATERIALS AND METHODS: A retrospective analysis was done of 36 kidneys treated during a 9-year period. Adjunctive therapy with bacillus Calmette-Guerin was given in 19 cases. RESULTS: Of 36 kidneys 6 were treated by immediate nephroureterectomy for aggressive disease, leaving 30 units treated by a complete course. The recurrence rate was 33%, which varied with histology as specific recurrence rates for grades 1 to 3 tumors (18%, 33% and 50%, respectively). The only cancer related mortalities occurred with grade 3 tumors. These tumors also had a higher incidence of understanding and vascular complications. Bacillus Calmette-Guerin therapy showed no significant improvement in survival. CONCLUSIONS: With vigilant followup, percutaneous management of transitional cell carcinoma of the renal collecting system is an acceptable alternative to nephroureterectomy in patients with grade 1 disease, grade 2 disease who are at risk for renal insufficiency and medical contraindications to a major open operation.

BCG Vaccine↗
PubMed1995

Extensive dilation of distal ureter for endoscopic treatment of large volume ureteral disease.

Two patients with large volume disease in markedly dilated ureters were treated endoscopically by wide dilation of the ureteral orifice and passage of larger nonureteroscopic endoscopes. The larger instruments provided better vision and the ability to work with larger tools, which greatly facilitated treatment without complication in patients who otherwise would have undergone an open procedure.

Adult↗
PubMed1994

Rapidly progressing atrophy of medial temporal lobe in Alzheimer's disease.

The symptoms of Alzheimer's disease are associated with pathological change and loss of neurons in the medial temporal lobe. By yearly temporal-lobe-oriented computed tomograms the average rate of atrophy of the medial temporal lobe was 15.1% per year (95% CI 10.0, 20.2) in 20 patients with histopathologically, confirmed Alzheimer's disease and 1.5% (0.2, 2.8) in 47 healthy ageing controls. Such excessive atrophy presumably reflects the vulnerability of the medial temporal lobe to a catastrophic event, probably a pathological cascade process. Thus, Alzheimer's disease may not be due simply to an acceleration of normal ageing but, rather, is the consequence of a true disease process.

Aged↗
PubMed1994

Design and construction of rhinovirus chimeras incorporating immunogens from polio, influenza, and human immunodeficiency viruses.

This paper describes the design and construction of chimeric human rhinoviruses that contain immunogenic regions from other pathogens as part of their surface coat proteins. Segments encoding the poliovirus 3 Sabin VP1 and VP2 proteins, the influenza hemagglutinin (HA) glycoprotein, and the human immunodeficiency virus gp120 surface and gp41 transmembrane glycoproteins were inserted into a full-length clone of human rhinovirus 14 (HRV14) at regions corresponding to neutralizing immunogenic sites IA (NIm-IA) and II (NIm-II). Of 12 chimeric constructs described, 3 produced viable virus. An HRV14 chimeric virus containing five amino acids of influenza HA (corresponding to 300 A2 of solvent-accessible surface area) had wild-type HRV14 growth characteristics and was neutralized by four of four anti-influenza HA antisera with reciprocal neutralizing titers ranging from 180 to 330. However, antisera raised in two guinea pigs against the HRV14:influenza HA chimera did not show significant neutralization of relevant strains of influenza. These results are the first to demonstrate the feasibility of making viable chimeras of human rhinoviruses displaying heterologous immunogens.

Amino Acid Sequence↗
PubMed1994

Monosynaptic innervation of facial motoneurones by neurones of the parvicellular reticular formation.

In order to determine whether neurones in the parvicellular reticular formation are in direct synaptic contact with motoneurones innervating facial muscles, a combined retrograde and anterograde transport study was carried out in the rat. Animals received injections of the retrograde tracer cholera toxin B conjugated to horseradish peroxidase into facial muscles and of the anterograde tracer biocytin into the parvicellular reticular formation. The facial motor nucleus was then examined for anterograde and retrograde labelling in the light and electron microscopes. Retrogradely labelled neurones were found in the facial motor nucleus with a distribution that was dependent on the muscles injected. Terminals anterogradely labelled with biocytin from the parvicellular reticular formation was observed in the motor nucleus amongst the retrogradely labelled neurones. At the electron microscope, the retrogradely labelled cells were found to receive input from unlabelled terminals and from terminals that were anterogradely labelled from the injections of biocytin in the parvicellular reticular formation. The labelled terminals were 1-2 microns in diameter at the active zone and packed with spherical vesicles. They formed both symmetrical and asymmetrical synapses with their labelled or unlabelled targets. It is concluded that neurones in the parvicellular reticular formation form direct synaptic contact with motoneurones of facial muscles. This may represent a pathway by which the basal ganglia can directly influence orofacial movement, as the substantia nigra is known to project to that part of the reticular formation.

Animals↗
PubMed1994

Endourologic management of obstructed hydrocalyx after blunt renal trauma.

Significant renal injuries caused by blunt trauma can produce early and delayed complications. We report a case of blunt trauma that resulted in what appeared to be a persistent encapsulated hematoma, but was in reality an obstructed hydrocalyx. Communication with the collecting system was re-established percutaneously by a method similar to that used in the management of caliceal diverticula.

Adolescent↗
PubMed1994

The effect of inhibition of synthesis, release, metabolism and uptake on the microdialysis extraction fraction of dopamine.

The present study was designed to determine the effects that synthesis, release, metabolism and uptake have on the in vivo extraction fraction (relative recovery) of dopamine (DA) in the nucleus accumbens of the rat. The extraction fraction and extracellular concentration of DA were established for rats that were perfused with artificial cerebrospinal fluid (aCSF) with or without substances inhibiting synthesis (100 microM alpha-methylparatyrosine (alpha-MPT)), release (1 microM tetrodotoxin (TTX)), uptake (1 microM, 20 microM cocaine or 1 microM GBR-12909) or metabolism (100 microM tropolone or 100 microM pargyline) with DA concentrations ranging from 0 to 200 nM. Inhibiting synthesis with alpha-MPT or release with TTX had no effect on the extraction fraction of DA. Inhibiting intracellular or extracellular metabolism with pargyline or tropolone, respectively, did not cause any changes in the extraction fraction. However, inhibiting uptake with 20 microM cocaine or 1 microM GBR-12909 decreased the extraction fraction by one-third and one-half, respectively. These results provide evidence that uptake is the primary neuronal process affecting the extraction fraction of DA in the nucleus accumbens and indicate that the extraction fraction may be useful as an index of DA uptake in vivo.

Animals↗