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Biomedical subjects

D G Assimos

Publications and source records attributed to D G Assimos.

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

Dietary oxalate and its intestinal absorption.

Dietary oxalate is currently believed to make only a minor contribution (< 20%) to urinary oxalate excretion. A recent prospective study of stone disease suggested that dietary oxalate may be a significant risk factor. This observation led us to re-evaluate the contribution of dietary oxalate to urinary oxalate excretion. Previous studies have been hampered by inaccurate food composition tables for oxalate and inadequate methods for studying intestinal oxalate absorption. This evidence as well as factors that modify oxalate absorption are reviewed. New approaches to measure food oxalate and intestinal oxalate absorption have been examined. Capillary electrophoresis appears to be well suited for the analysis of the oxalate content of food. Two individuals consumed an oxalate-free formula diet for 7 days. This diet decreased urinary oxalate excretion by an average of 67% (18.6 mg per 24 hours) compared to oxalate excretion on self-selected diets. The absence of detectable oxalate in feces by day 6 of the diet suggested that the intestinal absorption was minimal. However, an effect of the formula diet on endogenous oxalate synthesis cannot be excluded. Restoring oxalate to the formula diet increased urinary oxalate excretion and illustrates that this experimental protocol may be well-suited for studying oxalate absorption and factors that modify it. Our results suggest that the intestinal absorption of dietary oxalate makes a substantial contribution to urinary oxalate excretion and that this absorption can be modified by decreasing oxalate intake or increasing the intakes of calcium, magnesium, and fiber.

Animals↗
PubMed1994

Pretransplant urologic evaluation.

OBJECTIVE: Although a number of pretransplant urologic evaluations have been recommended in the literature, their efficacy has not been validated. This study was undertaken to evaluate a standardized urologic diagnostic protocol for potential adult transplant recipients. METHODS: One hundred consecutive adult transplant candidates were prospectively evaluated with a complete history and physical examination, renal ultrasonography (US), voiding cystourethrography (VCUG), urinalysis, and urine culture. Other diagnostic studies including cystoscopy and retrograde pyelography were performed as indicated. RESULTS: Urologic malignancies were diagnosed in 3 patients that included Stage A2 prostate cancer, Stage TA transitional cell carcinoma of the bladder, and Stage II renal cell carcinoma. The only significant abnormality detected by renal US was renal cell carcinoma in 1 patient. Twenty-six individuals had VCUG abnormalities, but these could not be predicted based on patient characteristics. However, VCUG was normal in all nondiabetic patients without voiding symptoms or a history of urinary tract infections. Thirteen patients had hematuria and were evaluated with cystoscopy and retrograde pyelography. One individual (7.6%) had a significant abnormality (bladder tumor) detected during cystoscopy. Retrograde pyelography demonstrated no clinically significant abnormalities in this patient group. Eighteen patients had sterile pyuria and underwent similar endoscopic evaluation. Cystoscopic examination was normal in all these individuals, and retrograde pyelography showed either normal or clinically insignificant papillary necrosis. CONCLUSIONS: Although renal US has a low diagnostic yield, all adult transplant candidates should undergo this study because of the high prevalence of renal cell carcinoma in this cohort. VCUG also should be performed prior to transplantation, but it may be omitted in nondiabetic patients without voiding symptoms or a history of urinary tract infection. Transplant candidates with hematuria warrant an endoscopic evaluation, although this may not be necessary in individuals with sterile pyuria.

Adult↗
PubMed1994

Changing incidence and etiology of iatrogenic ureteral injuries.

In the last decade there have been major advances in endoscopic surgery including ureteroscopy and laparoscopy, both of which may cause ureteral injury. We sought to determine if increased use of these procedures affected the frequency and nature of major iatrogenic ureteral injuries managed at our medical center. From 1980 to 1984 we treated 8 patients with such injuries compared to 19 patients treated from 1985 to 1989. The most recent period corresponded to the institution of ureteroscopy and the use of more aggressive laparoscopic procedures. Of the patients 14 sustained injuries at our center while 13 were referred from other institutions. Between 1985 and 1989 the incidence of injuries per total hospital admissions at risk increased from 4 to 11 per 10,000 (p = 0.0067), the incidence of urological injuries increased from 4 to 23 per 10,000 (p = 0.0071) and the incidence of injuries occurring in gynecologic patients increased from 13 to 41 per 10,000 admissions (p = 0.0385). There was no difference in the incidence of injuries in the general surgical population. From 1980 to 1984 no laparoscopic or ureteroscopic injuries occurred. However, from 1985 to 1989, 25% of gynecologic injuries occurred during laparoscopy and 70% of urological injuries were sustained during ureteroscopic procedures. Depending on the extent of the injury, patients were initially treated with either endourological or open surgical procedures. Good results were obtained in the majority of cases. Contemporary therapeutic strategies for treating patients sustaining ureteral injuries are discussed.

Female↗
PubMed1994

Nephrolithiasis Clinical Guidelines Panel summary report on the management of staghorn calculi. The American Urological Association Nephrolithiasis Clinical Guidelines Panel.

The American Urological Association Nephrolithiasis Clinical Guidelines Panel recommendations for managing struvite staghorn calculi are based on a comprehensive review of the treatment literature and meta-analysis of outcome data from the 110 pertinent articles containing viable, unduplicated data. The panel concluded that the 3 most significant outcome probabilities are those of being stone-free, undergoing secondary unplanned procedures and having associated complications. Panel guideline recommendations for most standard patients are that neither shock wave lithotripsy monotherapy nor open surgery should be a first-line treatment choice but that a combination of percutaneous stone removal and shock wave lithotripsy should be used.

Humans↗
PubMed1994

Inguinal lymphadenectomy and primary groin reconstruction using rectus abdominis muscle flaps in patients with penile cancer.

OBJECTIVES: The use of deep inferior epigastric artery (DIEA) rectus abdominis muscle flaps in conjunction with inguinal lymphadenectomy to treat patients with squamous cell carcinoma (SCC) of the penis having high-volume inguinal lymph node metastases causing skin breakdown and secondary infection is described. METHODS: Three patients with invasive SCC of the penis who had extensive unilateral inguinal nodal metastases with skin breakdown and secondary infection underwent pelvic lymphadenectomy and attempted wide resection of the superficial and deep inguinal lymph nodes. One patient had unresectable deep inguinal metastases and received postoperative radiation therapy. A DIEA rectus abdominis muscle flap was utilized to close the resulting groin defect. RESULTS: Pathologic analysis demonstrated no pelvic lymph node metastases in any of the patients, superficial inguinal lymph node metastases in 1, and superficial and deep inguinal lymph node involvement in 2. All wounds healed well. The 2 patients with deep inguinal metastases experienced local disease progression. One patient died 7 months postoperatively of complications from chronic renal failure but had no evidence of tumor recurrence or wound problems. Another patient died of recurrent disease. CONCLUSIONS: A rectus abdominis muscle flap may be a useful adjunct for managing certain patients with penile cancer and extensive suppurative inguinal lymph node metastases.

Biopsy, Needle↗
PubMed1994

Hemorrhagic cystitis in bone marrow transplantation.

OBJECTIVES: Patients undergoing bone marrow transplantation are at risk for hemorrhagic cystitis despite appropriate preventive measures. This complication could have an impact on patient survival and other outcome variables. METHODS: A retrospective study of patients subjected to bone marrow transplantation was conducted to determine risk factors for hemorrhagic cystitis and evaluate the impact of hemorrhagic cystitis on certain outcome variables. Patients who experienced hemorrhagic cystitis received various forms of therapy, at the discretion of the treating physician. RESULTS: Hemorrhagic cystitis occurred more frequently in younger patients and those undergoing allogeneic transplantation. The occurrence of hemorrhagic cystitis was associated with increased hospital costs, length of hospitalization, and mortality. Gender, race, type of malignancy, other pretransplantation comorbidity, and the occurrence of other peritransplantation complications were not associated with occurrence of hemorrhagic cystitis. CONCLUSIONS: Hemorrhagic cystitis is a significant complication of bone marrow transplantation, which influences economic and survival outcome. Since the number of bone marrow transplants being performed is increasing, urologists should be prepared to play an active role in treating patients who experience this complication.

Adolescent↗
PubMed1994

Role of laparoscopic pelvic lymph node dissection in the management of patients with penile cancer and inguinal adenopathy.

Patients with invasive squamous cell carcinoma of the penis and tumor involvement of the inguinal nodes are at risk for pelvic lymph node metastases. When this spread occurs, the chance for patient survival is limited. Because the sensitivity of CT in detecting pelvic lymph node metastases is low, open surgical pelvic lymphadenectomy is frequently performed. We have utilized laparoscopic pelvic lymphadenectomy as a minimally invasive alternative to this open approach in three patients with Stage T3 (UICC staging system) squamous cell carcinoma of the penis who had persistent inguinal adenopathy after a standard course of postpenectomy antiobiotic therapy. There were no intraoperative or postoperative complications, and all patients were discharged within 24 hours after surgery. The mean number of nodes removed was eight, and all specimens were free of tumor. Laparoscopic pelvic lymphadenectomy should be considered in patients with persistent inguinal adenopathy after antibiotic therapy before proceeding with inguinal lymph node dissection.

Carcinoma, Squamous Cell↗
PubMed1993

Effectiveness of laparoscopic varicocelectomy.

Laparoscopic varicocelectomy is a new technique which has been described in a limited number of clinical reports. We reviewed the results of 46 patients undergoing laparoscopic repair of 75 varicoceles over a two-year period to assess the effectiveness of this operative technique. The internal spermatic artery was preserved in 80 percent of the varicoceles and two arteries were present in 5 percent. Our ability to preserve the internal spermatic artery improved significantly with the use of the intraoperative Doppler probe after the first six months of performing this operation (p < 0.01). Nineteen infertile patients had a minimum follow-up of twelve months with seminal improvement in 68 percent and a pregnancy rate of 26 percent. Complications occurred in 2 patients (4%), inferior epigastric vessel bleeding in one, and genitofemoral nerve injury in the other. There was one persistent varicocele (1%). Our results with laparoscopic varicocelectomy are comparable with those reported with standard open surgical approaches.

Adolescent↗
PubMed1993

Effects of hemodialysis on prostate-specific antigen.

We undertook a prospective study to evaluate the effects of hemodialysis on serum prostate-specific antigen (PSA) in 26 male patients with end-stage renal disease as a clinical model for assessing the role of the kidney in PSA clearance. Patients ranging in age from fifty-one to eighty-three years (mean 64.8 years) underwent phlebotomy immediately before and after outpatient hemodialysis on a Monday/Wednesday/Friday or Tuesday/Thursday/Saturday schedule, with serum PSA values determined by the Abbott IMX Microparticle Enzyme Immunoassay. The mean +/- standard deviation for all post-dialysis PSA levels, 2.43 +/- 3.74, was significantly greater than that for pre-dialysis levels, 2.11 +/- 3.19 (p = 0.04). However, no statistically significant differences were found on comparing the combined pre- and post-dialysis PSA values over the course of the study (p = 0.2733) or when sequential pre-dialysis (p = 0.28) and post-dialysis (p = 0.92) levels were analyzed separately. We conclude that PSA is not eliminated by hemodialysis, and our results infer that it is not cleared by renal mechanisms.

Aged↗
PubMed1993

Obliterative pyeloureteritis: a complication of stone disease in patients with urinary conduit diversion.

In 4 patients with cutaneous urinary diversion who underwent percutaneous ureteral stone removal, similar ureteral complications developed as a result of severe ureteritis at the site of the stone. Ureteral narrowing occurred within days of percutaneous ureteral stone removal, progressing to complete occlusion in 2 cases. These complications led to prolonged hospitalization and additional procedures for each patient. One patient with an occluded ureter was lost to followup. Two patients responded satisfactorily to repeated ureteral dilations and prolonged stenting. One patient underwent excision of the affected ureteral segment. The average interval between tube placement and removal of tubes and stents was 15 weeks in 4 patients. The average inpatient period was 24 days. Patients with a cutaneous urinary conduit diversion may be at increased risk for complications following percutaneous treatment of ureteral stones. This risk may be secondary to an intense inflammatory response due to infection and other local factors.

Adult↗
PubMed1993

Relationship of protein intake to urinary oxalate and glycolate excretion.

The relationship of protein intake to urinary oxalate and glycolate excretion was examined in a large cohort (N = 101) of normal individuals on self-selected diets and in 11 individuals on controlled protein diets. On self-selected diets no correlation was detected between protein intake and urinary oxalate or glycolate excretion. A moderate but significant correlation (r = 0.45; P < 0.001) of oxalate with urea excretion was observed in males but not females, suggesting that there may be a link between urea and oxalate synthesis in males. On controlled protein diets mean oxalate excretion in females on days 7 to 10 of a high protein diet (1.8 g/kg body wt) was 20% higher than on a low protein diet (0.6 g/kg body wt; P = 0.02), but there was no difference in males. Glycolate excretion was significantly higher (P < 0.001) on the high protein diet than on the low protein diet in both sexes. Only a weak precursor-product relationship was observed between glycolate and oxalate. A gender effect was apparent on both self-selected and control diets with females excreting more oxalate and glycolate relative to creatinine than males. A pronounced inter- and intra-individual variability in the excretion of oxalate was observed, even on controlled diets. This suggests that genetic factors and physiological changes such as hormonal fluctuations may contribute more to the variability in oxalate excretion than the dietary intake of protein.

Adult↗
PubMed1991

Intraoperative renal ultrasonography: a useful adjunct to partial nephrectomy.

Several evolutionary changes in ultrasonographic instrumentation, including miniaturization of transducers and marked improvement in resolution, have made intraoperative renal ultrasonography a valuable adjunct for intrarenal surgery. We investigated its use in 6 patients undergoing partial nephrectomy for treatment of renal cell carcinoma. In addition, 14 kidneys with renal tumors were scanned immediately after radical nephrectomy and the specimens were subjected to simulated partial nephrectomy. Transverse and longitudinal real-time sonographic images were obtained with a 5 MHz. sector scanner or a 7.5 MHz. convex array transducer. With ultrasonography to define tumor extent and location, negative surgical margins were obtained in all 6 individuals undergoing partial nephrectomy. A negative surgical margin was obtained in 13 of the 14 radical nephrectomy specimens subjected to simulated partial nephrectomy. A small satellite lesion was not identified and not resected in 1 of the radical nephrectomy specimens. We found that intraoperative renal ultrasonography helps to identify the location and extent of deep intraparenchymal lesions. It also provides a guide for a more accurate nephrotomy, which facilitates the attainment of negative resection margins during partial nephrectomy.

Carcinoma, Renal Cell↗
PubMed1991

Spontaneous perinephric hemorrhage: imaging and management.

We report on 10 patients with spontaneous perinephric hemorrhage associated with underlying disease, including renal cell carcinoma (5), angiomyolipoma (2), malignant melanoma (1), periarteritis nodosa (1) and severe portal hypertension (1). The etiology could not be identified with computerized tomography (CT) in 5 cases (50%), including 2 renal cell carcinomas, 1 angiomyolipoma, 1 periarteritis nodosa and 1 portal hypertension. Arteriography demonstrated underlying lesions in 4 of these 5 cases (80%) including the case of vasculitis. CT combined with magnetic resonance imaging is accurate for the diagnosis of spontaneous perinephric hemorrhage but the underlying pathological condition is often undetectable in the acute phase due to the perinephric blood. CT should be the first study performed if this diagnosis is suspected. Arteriography is recommended if a renal mass is not detected. If a mass is not identified with these 2 imaging studies and the patient is clinically stable, followup thin slice CT should be performed.

Adult↗
PubMed1991

A comparison of anatrophic nephrolithotomy and percutaneous nephrolithotomy with and without extracorporeal shock wave lithotripsy for management of patients with staghorn calculi.

A retrospective study was conducted comparing anatrophic nephrolithotomy (10 cases), percutaneous nephrolithotomy alone (4 cases) or percutaneous nephrolithotomy combined with extracorporeal shock wave lithotripsy (23 cases) for the treatment of large staghorn calculi. A comparison based on collecting system anatomy demonstrated that anatrophic nephrolithotomy resulted in a greater stone-free rate, shorter hospitalization and lower costs while complication rates were similar. Anatrophic nephrolithotomy should still be considered a viable treatment option, especially for patients with large branched calculi in complex collecting systems.

Adult↗
PubMed1990

Association of antisperm antibodies with chronic nonbacterial prostatitis.

Antisperm antibodies are significant in male factor infertility. The prevalence of antisperm antibodies in the infertile population is approximately 10 percent, and it is not cost-effective to test for these antibodies in every male partner of an infertile marriage. Earlier studies have demonstrated a higher prevalence of antisperm antibodies among men with a history of bacterial prostatitis or urethritis. Because of this established association, we measured the prevalence of serum antisperm antibodies, using a gel agglutination assay, in 28 men with chronic nonbacterial prostatitis and in age-matched control group of 69 men without a history of prostatitis. The prevalence was 25 percent (test subjects) and 7.2 percent (controls) (p less than 0.05). This finding indicates that nonbacterial prostatitis is a risk factor for the presence of serum antisperm antibodies and that subfertile men with a history of nonbacterial prostatitis should be tested for these antibodies.

Adult↗