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Biomedical subjects

P Choyke

Publications and source records attributed to P Choyke.

25 records · Page 2Linked to original sources
PubMed1992

The urological manifestations of chronic granulomatous disease.

Chronic granulomatous disease is a rare disorder of phagocytic cell oxidative metabolism. Patients have recurrent infections with catalase positive organisms and granulomatous lesions throughout the body. The genitourinary tract can be an occult site of involvement. We reviewed the prevalence of urological abnormalities in 60 patients with chronic granulomatous disease. Chart review revealed that 23 of the 60 patients (38%) had urological manifestations. Seven patients had 10 ureteral strictures. Treatment of the granulomatous strictures with steroids caused at least a temporary decrease in size or a resolution of the granulomas and strictures with steroids caused at least a temporary decrease in size or a resolution of the granulomas and relief of the obstruction. Three patients had bladder granulomas and 1 had a urethral stricture. A total of 12 patients had urinary tract infections and 7 had altered renal function. Ten patients had other manifestations of genitourinary disease. Abnormalities in the urinary tract are relatively frequent. Risk factors include X-linked disease and low percentile weight. Genitourinary manifestations can cause significant morbidity in chronic granulomatous disease patients. A variety of therapies, including judicious use of steroids and gamma-interferon, are proving to be useful in the treatment of this disorder and in some cases they may offer a nonoperative alternative for relief of chronic granulomatous obstructive disease in these patients.

Female↗
PubMed1992

Suramin: a novel growth factor antagonist with activity in hormone-refractory metastatic prostate cancer.

PURPOSE: Suramin is known to inhibit the growth of malignant prostate carcinoma cells in vitro. This led us to evaluate the effectiveness of suramin in the treatment of 38 patients with prostate carcinoma refractory to hormone therapy. PATIENTS AND METHODS: Suramin was administered by continuous infusion at a rate designed to reach a peak of 300 micrograms/mL at the end of 14 days. Patients were given 8 weeks to recover from any toxicity before beginning the second cycle. Subsequent cycles were administered in the same manner except the starting dose rate was 280 mg/m2. RESULTS: In 17 patients with measurable soft tissue disease, three had complete disappearance of soft tissue disease for 4, 5, and 11 months, whereas three patients had a greater than or equal to 50% decrease in the sum of the products of the diameters of all measurable disease for greater than or equal to 1 month. Of these 17 patients, pretreatment prostate-specific antigen (PSA) decreased by 75% or more in five (29%) and normalized in one (6%). The remaining 21 patients had disease limited to bone, and only one of these experienced resolution of more than 50% of all lesions on bone scan. Of these 21 patients, pretreatment PSA decreased by 75% or more in eight (38%) and normalized in five (25%). Median time to progression for all patients was 26.3 weeks, and median survival was 42.3 weeks. Patients with bone involvement alone exhibited a better survival than patients with soft tissue involvement (P2 = .02). Survival was strongly correlated (P2 = .0001) with a decline in the pretreatment PSA of greater than or equal to 75% by the eighth week on therapy, with nearly an 85% survival at 1 year compared with a 20% survival for those whose pretreatment PSA did not decline by that amount. CONCLUSION: We conclude that suramin is an active agent in hormone-refractory prostate carcinoma.

Aged↗
PubMed1991

Von Hippel-Lindau (VHL) disease: distinct phenotypes suggest more than one mutant allele at the VHL locus.

As part of an attempt to locate the von Hippel-Lindau locus (VHL) on chromosome 3, we evaluated 41 families with von Hippel-Lindau disease from the United States and Canada. One large family was identified whose disease phenotype was distinct from typical VHL. The most common disease manifestation was pheochromocytoma occurring in 57% (27/47) of affected family members. Few (4/47) affected family members had symptomatic spinal or cerebellar hemangioblastomas; no affected family member had renal cell carcinoma (0/47) or pancreatic cysts (0/24). Previously, genetic analysis demonstrated that the disease manifestations in this family were linked to RAF1 and D3S18, markers shown to be linked to typical VHL. These results suggest that there are mutant alleles at the VHL locus associated with distinct tissue specificities.

Adrenal Gland Neoplasms↗
PubMed1990

Localization of the von Hippel-Lindau disease gene to a small region of chromosome 3.

We studied 25 families with von Hippel-Lindau disease (VHL) to locate VHL more precisely on chromosome 3. We found that VHL was linked to RAF1, confirming previous observations, and to two polymorphic DNA markers, D3S18 and D3S191. Multipoint linkage analysis indicated that the most likely location for VHL was in the interval between RAF1 and D3S18. D3S18 was located at 3p26. Genetic heterogeneity was not detected in this panel of von Hippel-Lindau disease families. The polymorphic markers RAF1, D3S18, and D3S191 should be useful in identifying asymptomatic gene carriers in VHL families and in guiding efforts at gene isolation.

Chromosome Mapping↗
PubMed1989

Prospective evaluation of hepatic imaging studies in the detection of colorectal metastases: correlation with surgical findings.

Nineteen patients with isolated colorectal liver metastases were preoperatively evaluated with five hepatic imaging studies. The results of these studies were correlated with operative findings. One study involved the use of EOE-13, an intravenously administered lipid contrast agent that enhances liver parenchyma on computed tomography (CT) scans (EOE-CT). Another study, arterial portography (AP-CT), was performed with injection of a water-soluble contrast agent into the superior mesenteric artery during CT scanning. Delayed CT scanning (DS-CT) was completed 4 hours after AP-CT. In addition, T1- and T2-weighted magnetic resonance imaging (MRI) (T1-MRI, T2-MRI) scans were done. All patients subsequently underwent laparotomy with identification of 78 lesions. A lesion-by-lesion analysis revealed that the sensitivity of EOE-CT (83%), AP-CT (78%), DS-CT (82%), and T1-MRI (84%) was comparable. T2-MRI had a significantly lower sensitivity (64%) compared with EOE-CT, DS-CT, and T1-MRI. The false-positive rate for AP-CT was 31%, which was significantly higher than that of all other studies. The T1-MRI examination had the lowest false-positive rate and proved to be the best hepatic imaging study in the detection of colorectal metastases. EOE-CT and DS-CT were comparable, whereas AP-CT and T2-MRI proved to be inferior tests.

Colorectal Neoplasms↗
PubMedDate not supplied

Improving image contrast using principal component analysis for subsequent image segmentation.

This article presents a technique for improving MR image contrast by linearly combining multiple MR images with different tissue contrast. The weighting coefficients of the linear combination are derived using principal component analysis. The contrast-enhanced composite image is segmented subsequently using gray level-based 1D segmentation methods. The technique reduces a multispectral image set to composite eigenimages and allows application of appropriate 1D segmentation methods that do not have equivalent counterparts in multispectral methods.

Brain↗