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Biomedical subjects

D M Bolton

Publications and source records attributed to D M Bolton.

At least 19 recordsLinked to original sources
PubMed2004

18F-fluorodeoxyglucose positron emission tomography in evaluation of germ cell tumor after chemotherapy.

OBJECTIVES: To evaluate the role of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) in the assessment of germ cell tumors after chemotherapy. METHODS: We reviewed patients' records for the histologic findings and clinical outcome. 18F-FDG PET results were correlated with tissue histologic features where available; and if not available, the correlation was with the clinical outcome. RESULTS: A total of 45 PET studies were performed on 38 patients (age range 19 to 64 years, median 31). All patients had received chemotherapy. In the nonseminomatous germ cell tumor (NSGCT) group, of the 31 patients with one scan, 18 PET scans were reported as positive, with only 2 not having active disease. Of the 12 negative scans, 6 showed teratoma, 1 tumor, and 5 did not show active disease. The equivocal scan revealed thyroid adenoma. In the seminoma group, the PET scans correlated well with the clinical and histologic outcomes. Four patients underwent salvage chemotherapy, and in this subgroup, the PET findings also correlated with the outcome. CONCLUSIONS: (18)F-FDG PET is a promising tool as an adjunct to current imaging techniques in detecting residual viable germ cell tumor after chemotherapy. In NSGCT, a positive PET scan was accurate in 16 of 18 patients, although negative PET studies did not exclude the presence of disease, mainly because of the presence of teratoma. In seminoma, a negative 18F-FDG PET study correlated with a favorable clinical outcome. PET was also predictive of the response to salvage chemotherapy and was highly specific for active tumor in both NSGCT and seminoma.

Adult↗
PubMed2001

Gastric patch pyeloplasty: development of an animal model to produce upper tract urinary acidification for treating struvite urinary calculi.

PURPOSE: Struvite calculi form in an alkaline environment created by urease producing uropathogens. We developed a viable upper tract urinary acidification model by performing gastric patch pyeloplasty in the rabbit. This model produces urinary acidification sufficient for the treatment and prevention of struvite renal calculi. We evaluated the physiological, metabolic and surgical outcomes. MATERIALS AND METHODS: gastric segment was harvested based on branches of the left gastro-epiploic artery. The flap was folded along the transverse axis and the adjacent edges were closed. The mouth of this reconfigured pouch provided optimal dimensions for anastomosis with the diminutive renal pelvis. Half of the rabbits were treated with internal stenting and H-2 blockade. Urinary pH was assessed by weekly cage collection and direct collection from the cannulated ureters. Urine culture was done, and serum gastrin and electrolytes were assessed at regular intervals. The rabbits were sacrificed at 3 to 26 weeks. Histological examination was routinely performed. RESULTS: A total of 15 rabbits were available for complete assessment. Sustained urinary acidification was produced in 7 animals (47%) with a mean pH decrease of 2.27. In another 2 rabbits (13%) the urine was initially acidic but subsequently became alkaline due to ureteral obstruction. Electrolytes and gastrin were unchanged in these rabbits and urine culture was positive in 2. Histological testing revealed nonspecific inflammatory changes of the renal pelvis. Anastomotic complications were the most common surgical complication and the most common cause of failed acidification. The cohort treated without stents and H-2 blockade was at significantly greater risk for anastomotic leakage. CONCLUSIONS: Gastric patch pyeloplasty may significantly increase urinary acidity in the rabbit model without altering the serum electrolyte balance or gastrin level. The procedure utilizes common techniques of reconstructive urology and may be possible with laparoscopy. Further study is required to assess the in vivo effect of this procedure for treating and preventing upper tract struvite calculi.

Animals↗
PubMed2001

Clinical role of F-18 fluorodeoxyglucose positron emission tomography for detection and management of renal cell carcinoma.

PURPOSE: We evaluate the accuracy of F-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET) for staging and management of renal cell carcinoma. MATERIALS AND METHODS: FDG-PET was performed in 25 patients with known or suspected primary renal tumors and/or metastatic disease and compared with conventional imaging techniques, including computerized tomography (CT). Histopathological confirmation was obtained in 18 patients and confirmation of the disease was by followup in the remainder. The impact of FDG-PET on disease management was also assessed. RESULTS: Of the 17 patients with known or suspected primary tumors FDG-PET was true positive in 15, true negative in 1 and false-negative in 1. Comparative CT was true positive in 16 patients and false-positive in 1. The accuracy of FDG-PET and CT was similar (94%). All patients would have undergone radical nephrectomy after conventional imaging findings but FDG-PET results altered treatment decisions for 6 (35%), of whom 3 underwent partial nephrectomy and 3 avoided surgery due to confirmation of benign pathology or detection of unsuspected metastatic disease. Of the 8 cases referred for evaluation of local recurrence and/or metastatic disease FDG-PET changed treatment decisions in 4 (50%), with disease up staged in 3 and recurrence excluded in 1. Compared with CT, FDG-PET was able to detect local recurrence and distant metastases more accurately and differentiated recurrence from radiation necrosis. CONCLUSIONS: FDG-PET accurately detected local disease spread and metastatic disease in patients with renal cell carcinoma and altered treatment in 40%. FDG-PET may have a role in the diagnostic evaluation of patients with renal cell carcinoma preoperatively and staging of metastatic disease.

Adult↗
PubMed2000

Prostate cancer in Victoria in 1993: patterns of reported management.

OBJECTIVE: To describe the management of newly diagnosed prostate cancer in 1993 during the early prostate specific antigen (PSA) era. DESIGN: Survey of medical practitioners involved in the management of a total sample of incident prostate cancer cases selected from a population-based cancer registry. The survey was conducted in 1996, and the sample was followed up until 1998, to obtain five-year survival data on all patients. SETTING: The State of Victoria, including both public and private health sectors. PATIENTS: All men who were newly diagnosed with prostate cancer in the six months January-June 1993. MAIN OUTCOME MEASURES: Reported management by method of diagnosis; staging investigations; and treatment by observation, hormonal therapy, radical radiotherapy or radical prostatectomy. RESULTS: 1048 of 1117 (94%) cases diagnosed were surveyed. Most of the men (858 [82%]) were older than 65 years: 117 (11%) cancers were detected by screening asymptomatic men, and a further 269 (26%) were found by testing of men with symptoms ("case-found"). The 259 (25%) men treated with definitive local therapies (prostatectomy and curative radiotherapy) were younger (< 75 years), and their disease was clinically more localised (clinical stage, T1-2) and they were often found by screening or case-finding. Men given hormonal therapy (407; 39%) or managed without treatment (373; 36%) tended to be older and more likely to have been diagnosed by transurethral resection of the prostate (TURP). The overall relative survival at five years was 86% and was decreased in men with cancers of higher histological grade or more advanced clinical stage, or who had higher PSA levels. CONCLUSIONS: Although a third of patients were detected by screening or case-finding early in the PSA era, definitive local therapies were used infrequently (25% of the total sample). Most received appropriate treatment.

Age Factors↗
PubMed1999

The impact of contemporary bladder management techniques on struvite calculi associated with spinal cord injury.

OBJECTIVE: To evaluate the incidence, risk factors and complications of upper tract struvite calculi, often associated with spinal cord injury (SCI), as such patients have a high incidence of urinary infection complicating their neurogenic voiding dysfunction, by reviewing a large population of patients with SCI in whom modern techniques of bladder management were used. PATIENTS AND METHODS: Between 1982 and 1996, 1669 patients with SCI were admitted to our institution; 1359 of these patients sustained their injuries during the study period. During this time, their bladder management was based on urodynamic and imaging criteria, using techniques such as early intermittent catheterization, sphincterotomy and bladder augmentation where possible to create a catheter-free, low-pressure reservoir. All instances of upper tract struvite calculi in this population were documented. Risk factors for stone development, presentation and complications, management and recurrence rates were assessed. RESULTS: Over the 15 years, 58 patients (3.5% of the SCI population) were treated for a total of 144 episodes of struvite calculi. The incidence of stones in those injured since 1982 was 1. 5%; 67% of these patients had complete spinal cord lesions, 54% had lesions of the cervical cord and 53% developed their first stone >10 years after injury. Only 22% presented within 2 years of injury. The group of patients developing stones had a significantly higher incidence of indwelling catheters (49%), bladder stones (52%) and vesico-ureteric reflux (28%) than those who were stone-free. The development of recurrent urinary tract infections was the most common mode of presentation. The stone-free rate after treatment was 87%. Normal renal function was preserved in 72% of patients. CONCLUSIONS: In a large population of patients with SCI managed using contemporary bladder techniques the incidence of upper tract calculi was 3.5%; 30% of these stones were complete or partial staghorns. Those patients with complete cord lesions, permanent indwelling catheters and vesico-ureteric reflux were at the highest risk. Stone clearance was 87% and recurrent stones occurred in 69% of patients. Struvite renal calculi continue to be a significant problem in the spinal cord injury population.

Adolescent↗
PubMed1996

Voiding dysfunction in human immunodeficiency virus infections.

PURPOSE: We prospectively evaluated the current spectrum of urodynamic pathology in patients infected with human immunodeficiency virus (HIV) who presented with voiding dysfunction. MATERIALS AND METHODS: We obtained a directed genitourinary and neurological history, and performed a physical examination and urodynamic testing in 18 patients. A 4-channel membrane urethral catheter was used to record intravesical and intraurethral pressures simultaneously. RESULTS: Detrusor hyperreflexia was present in 28% of our patients and detrusor-sphincter dyssynergia in 28%. Detrusor areflexia, previously described as the most frequent abnormality, was uncommon in our series (6% of patients). CONCLUSIONS: This changing proportion of urodynamic diagnoses may reflect a changing pattern of neurological manifestations of HIV infection due to more aggressive management. Urodynamic evaluation remains critical for precise diagnosis and treatment in patients with HIV who present with urinary symptoms.

Adult↗
PubMed1995

Current indications for open stone surgery in an endourology center.

OBJECTIVES: To evaluate the current indications and outcome of open stone surgery in a tertiary endourology unit. METHODS: A 3-year retrospective review (1990 to 1993) of all endoscopic and open stone surgery was undertaken. RESULTS: Twenty-five open procedures were performed on 20 patients of a total of 799 stone treatment procedures (3.13%). The most common indications for open stone surgery included large stone burdens in association with abnormal anatomy limiting endoscopic access (31%), concurrent open surgical procedures (24%), or previous failed endourologic procedures (17%). Anatomic factors contributing to the need for open surgery included renal transplantation, morbid obesity, and severe limb contractures. CONCLUSIONS: Open stone surgery has become more complex. Patients undergoing open surgery, who failed endourologic techniques, or for anatomic or medical reasons, currently are the cohorts who may still benefit from treatment for calculus disease using open surgical techniques.

Female↗
PubMed1995

Pseudo-crossed renal ectopia secondary to ureteropelvic junction obstruction.

To our knowledge we report the first case of pseudo-crossed renal ectopia without an apparent displacing retroperitoneal mass that was documented on sequential radiological studies. Ureteropelvic junction obstruction of the crossed kidney appeared to be the cause of pseudo-crossed renal ectopia. Our case is compared with previously described instances of pseudo-crossed renal ectopia and the pathophysiological basis of this condition is discussed.

Adult↗
PubMed1995

Endoscopic treatment of a giant ileal conduit calculus.

A giant ileal conduit calculus is an uncommon complication of urinary diversion, with few recent reports present in the English literature. To date all described instances have necessitated treatment by laparotomy. The first reported successful management of such a condition by purely endoscopic means is reported.

Adult↗
PubMed1995

The effect of newer generation lithotripsy upon renal function assessed by nuclear scintigraphy.

PURPOSE: We studied the effect of second generation lithotripsy on renal function. MATERIALS AND METHODS: We evaluated 42 patients with unilateral renal calculi by nuclear renography, serum creatinine levels, renal ultrasonography and plain radiographs. RESULTS: There was no significant change in glomerular filtration rate at 1 or 3 months. Split function of the treated kidneys was lower at 1 month (mean 47.2%, p = 0.01) and 3 months (47.3%, p = 0.01) than before treatment (49.1%). A greater than 5% decrease in split function of the treated kidney occurred at 1 month in 6 patients (16.2%) and at 3 months in 3. Of the patients 23 (62.2%) were stone-free and 11 had residual fragments less than 4 mm., with a 19% retreatment rate for an overall success rate of 91.9%. CONCLUSIONS: Newer generation lithotriptors may limit renal damage while permitting satisfactory treatment of renal calculi.

Adult↗
PubMed1995

Entrapped Malecot nephrostomy tube: etiology and management.

Nephrostomy tubes occasionally are resistant to extraction. During the last 7 years 3 such patients with entrapped Malecot nephrostomy tubes have been treated successfully at our university. The entrapped nephrostomy tubes were removed by endoscopically incising an anchoring tissue bridge that had grown over a flange. A small endoscope was easily advanced through the lumen of the entrapped catheter to allow for adequate visualization and electrocautery of the anchoring tissue bridge. With this method an entrapped Malecot nephrostomy tube may be removed intact without significant injury to the renal parenchyma. Malecot nephrostomy tubes should be used with caution for long-term drainage of small intrarenal pelves.

Child↗
PubMed1995

Endocervicosis of the bladder.

We report a case of endocervicosis of the bladder. The tumor was successfully resected transurethrally. Histopathology of this rare condition is discussed and the literature is reviewed. The natural course of this entity is poorly documented and close followup is mandatory. When endocervicosis is differentiated confidently from adenocarcinoma, local treatment may be satisfactory.

Adenocarcinoma↗
PubMed1994

CO2 laser subcapsular orchidectomy in the treatment of metastatic prostate cancer.

Hormonal manipulation remains the main method of treatment in metastatic carcinoma of the prostate. Traditional techniques of surgical castration may result in complications due to bleeding within the scrotum. Because of its cutting and hemostatic properties, superior to that seen with traditional scalpel incisions in vessels < 1.5 mm diameter, the carbon dioxide laser has been used in performing subcapsular orchidectomy in an attempt to reduce such complications. Postoperative hormonal assays have demonstrated a response identical to orchidectomy, and no treatment complications were encountered in our series. Subcapsular orchidectomy using the carbon dioxide laser may offer an advantage over traditional methods of surgical castration by reducing the frequency of postoperative hematoma.

Humans↗
PubMed1994

Urologist directed percutaneous nephrostomy tube placement.

A retrospective analysis of 100 consecutive ultrasonically guided percutaneous nephrostomy tubes placed under the guidance of urologists was done. Complications related to tube insertion included sepsis in 3% of the cases, renal pelvic perforations in 2% and hemorrhage in 1%. There were no deaths and no need for open surgical intervention to manage these complications. An additional 21% of the tubes malfunctioned more than 24 hours after insertion, including dislodgement in 11%, occlusion in 6%, hemorrhage in 1%, peritubular leakage in 1%, puncture site infection in 1% and severe incrustation in 1%. These delayed complications were independent of tube type. Nephrostomy tubes may be placed safely by urologists. Urologists usually direct the need for percutaneous nephrostomy tube placement and use these ports for endourological manipulations and, therefore, they should have a greater role in catheter insertion.

Adult↗
PubMed1994

Histopathological changes in human prostatic adenoma following neodymium:YAG laser ablation therapy.

Transurethral laser ablation of the prostate is a procedure currently under evaluation as an alternative to transurethral resection of the prostate in the management of benign prostatic hyperplasia. Removal of prostatic tissue by endoscopic resection or open surgical techniques from 7 patients in whom prostatic laser ablation was previously attempted offered an opportunity to evaluate the sequential effects of such energy upon the human prostate at varying intervals after treatment. A progressive inflammatory and necrotic response, initially akin to that demonstrated after a thermal burn, together with evolving vascular changes within the residual viable prostatic tissue were demonstrated. Our study demonstrates the changes in the human prostate whereby neodymium:YAG laser energy causes a deep coagulative necrosis and arterial thrombosis in the prostatic adenoma. These changes differ significantly from those noted in canine studies. A slower cavitation effect is observed in the human compared with the canine, and this finding mirrors the continuing clinical improvement in voiding parameters with time.

Aged↗
PubMed1994

Improved renal function following aggressive treatment of urolithiasis and concurrent mild to moderate renal insufficiency.

To our knowledge the prevalence of urinary stone disease and concurrent mild to moderate renal insufficiency has never been reported. A review of our last 2,000 urinary stone patients identified 33 (1.65%) with serum creatinine levels of 2.0 mg./dl. or greater at presentation. Chemical composition, location and complexity of the calculi, types of procedures required to render the patient stone-free and the effect of surgical intervention (independent of relief of obstruction) on renal function were evaluated. Mean serum creatinine level before surgical intervention and after placement of a ureteral stent or percutaneous nephrostomy tube in patients with evidence of obstruction was 3.2 mg./dl. (range 2.0 to 7.5). Complete or partial staghorn calculi were found in 21 of the 33 patients (64%), including 8 with bilateral staghorn calculi. Seven patients required 1 procedure, 1 required urinary alkalization alone and the other 25 required an average of 3.5 procedures each. Stone analysis revealed struvite, mixed calcium and uric acid to be the most common types. Followup creatinine values (the latest available within 1 year) and corresponding creatinine clearances showed remarkable improvement. The mean decrease in serum creatinine level was 1.2 mg./dl. (p < 0.001). There was no statistically significant difference in the rate of decrease between patients with pretreatment serum creatinine levels of 2.0 to 2.9 mg./dl. and those with initial values of 3.0 or more. Renal calculi and concurrent mild to moderate renal insufficiency warrant aggressive treatment. Patients demonstrate significant improvement in renal function independent of relief of obstruction.

Adult↗
PubMed1994

Management of benign prostatic hyperplasia by transurethral laser ablation in patients treated with warfarin anticoagulation.

Transurethral laser ablation of the prostate gland was used to treat benign prostatic hyperplasia in 10 patients on warfarin anticoagulant therapy who had either significant clinical symptoms or who were in urinary retention. Anticoagulant therapy did not require alteration at any stage during treatment. All patients noticed improvements in symptom score assessments, flow rates and residual urine volumes following this procedure, and no significant complications were encountered. The hemostatic nature of neodymium:YAG laser energy as applied in this procedure appears to result in a technical improvement upon conventional transurethral resection for the treatment of symptomatic benign prostatic hyperplasia in patients taking warfarin anticoagulant therapy.

Aged↗