sepharose and Prostatic-Hyperplasia

Tissue-mimicking gels provide a cost-effective medium to optimize histotripsy treatment parameters with immediate feedback. Agarose and polyacrylamide gels are often used to evaluate treatment outcomes as they mimic the acoustic properties and stiffness of a variety of soft tissues, but they do not exhibit high toughness, a characteristic of fibrous connective tissue. To mimic pathologic fibrous tissue found in benign prostate hyperplasia (BPH) and other diseases that are potentially treatable with histotripsy, an optically transparent hydrogel with high toughness was developed that is a hybrid of polyacrylamide and alginate. The stiffness was established using shear wave elastography (SWE) and indentometry techniques and was found to be representative of human BPH ex vivo prostate tissue. Different phantom compositions and excised ex vivo BPH tissue samples were treated with a 700-kHz histotripsy transducer at different pulse repetition frequencies. Post-treatment, the hybrid gels and the tissue samples exhibited differential reduction in stiffness as measured by SWE. On B-mode ultrasound, partially treated areas were present as hyperechoic zones and fully liquified areas as hypoechoic zones. Phase contrast microscopy of the gel samples revealed liquefaction in regions consistent with the target lesion dimensions and correlated to findings identified in tissue samples via histology. The dose required to achieve liquefaction in the hybrid gel was similar to what has been observed in ex vivo tissue and greater than that of agarose of comparable or higher Young's modulus by a factor >10. These results indicate that the developed hydrogels closely mimic elasticities found in BPH prostate ex vivo tissue and have a similar response to histotripsy treatment, thus making them a useful cost-effective alternative for developing and evaluating different treatment protocols.

Topics: High-Intensity Focused Ultrasound Ablation; Humans; Hydrogels; Male; Phantoms, Imaging; Prostatic Hyperplasia; Sepharose

Enzyme ablation of the hyperplastic prostate may be an ideal method of management of BPH. However, the unsatisfactory ablation affects in vivo contrast with successful in vitro results limiting the enthusiasm for further research. In this study, we make efforts to solve the problems in the use of enzyme ablation of BPH in vivo and to measure satisfactory effect.. A total of 18 hybrid dogs between the ages of 7 and 11 y underwent this experiment. Eight dogs were divided into four groups according to the injection formula: enzyme solution, hot D-Hanks' plus enzyme solution, hot agarose plus enzyme solution, and hot agarose solution alone. After selecting the agarose plus enzyme solution group in the first month, the remainder 10 dogs were treated with this two-stage method. Intravenous or oral antibiotics were administered perioperatively. All operations were performed directly by way of laparotomy. The prostates were observed and harvested with surrounding tissue at 24 hrs, 7 days, 14 days, 1 month and 3-5 months after treatment. Gross and microscopic examinations were performed.. Only agarose plus enzyme group shows obvious cavity formation with concomitant size reduction and softening of the prostate ablation effect in the four groups. At 24 h after injection, the prostates demonstrated cavity formation containing liquefied necrotic tissue. The liquefied tissue was absorbed in 7-14 days. At 1 month, the size of most prostates decreased with a corresponding decrease in the size of the cavities. The cavities nearly disappeared within 3-5 months, and the size of prostates decreased to between 1/2 and 1/4 of the pretreatment sizes. All prostates had intact urethral mucosa and capsule. No complications directly related to enzyme ablation were identified. In the control groups there were no significant cavities or decrease in prostate size.. This two-stage thermal and enzyme ablative method can significantly ablate prostate tissue without identifiable complications, and would be possibly applied to treating human BPH in the future.

Topics: Administration, Oral; Animals; Anti-Bacterial Agents; Collagenases; Combined Modality Therapy; Dogs; Hot Temperature; Injections, Intravenous; Laparotomy; Male; Pilot Projects; Prostate; Prostatic Hyperplasia; Sepharose; Trypsin

We determined the optimal conditions for the separation of N-glycosylation variants of prostate-specific antigen using concanavalin A. Concanavalin A is a lectin that binds to the terminal sugar residues of glycoproteins. We demonstrated that differences in the percentage of prostate-specific antigen bound to concanavalin A-Sepharose in patients with benign prostatic hyperplasia compared with patients with prostatic carcinoma, as described in the literature, arise when insufficient concanavalin A binding sites are added for complete binding of the glycosylation variants of prostate-specific antigen. We observed similar percentages of prostate-specific antigen bound to concanavalin A-Sepharose for benign prostatic hyperplasia (86.3% +/- 7.5, mean +/- SD) and carcinoma patients (81.8% +/- 12.0, mean +/- SD), when sufficient concanavalin A-Sepharose was added to allow optimal binding, and when samples with high prostate-specific antigen concentrations were not pre-diluted before incubation with concanavalin A-Sepharose. We conclude that differentiation of patients with benign prostatic hyperplasia or carcinoma of the prostate on the basis of differences in percentages of prostate-specific antigen bound to concanavalin A-Sepharose, i.e. separation of N-glycosylation variants, is not possible.

Topics: Binding Sites; Carcinoma; Chromatography, Affinity; Concanavalin A; Glycosylation; Humans; Male; Prostate-Specific Antigen; Prostatic Hyperplasia; Prostatic Neoplasms; Sepharose

Topics: Antigens, Neoplasm; Humans; Male; Prostate-Specific Antigen; Prostatic Hyperplasia; Prostatic Neoplasms; Sepharose