Biomedical subjects

Jennifer Brainard

Publications and source records attributed to Jennifer Brainard.

7 recordsLinked to original sources

PubMed2003

Molecular pathway for cancer metastasis to bone.

The molecular mechanism leading to the cancer metastasis to bone is poorly understood but yet determines prognosis and therapy. Here, we define a new molecular pathway that may account for the extraordinarily high osteotropism of prostate cancer. By using SPARC (secreted protein, acidic and rich in cysteine)-deficient mice and recombinant SPARC, we demonstrated that SPARC selectively supports the migration of highly metastatic relative to less metastatic prostate cancer cell lines to bone. Increased migration to SPARC can be traced to the activation of integrins alphaVbeta3 and alphaVbeta5 on tumor cells. Such activation is induced by an autocrine vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR)-2 loop on the tumor cells, which also supports the growth and proliferation of prostate cancer cells. A consequence of SPARC recognition by alphaVbeta5 is enhanced VEGF production. Thus, prostate cancer cells expressing VEGF/VEGFR-2 will activate alphaVbeta3 and alphaVbeta5 on their surface and use these integrins to migrate toward SPARC in bone. Within the bone environment, SPARC engagement of these integrins will stimulate growth of the tumor and further production of VEGF to support neoangiogenesis, thereby favoring the development of the metastatic tumor. Supporting this model, activated integrins were found to colocalize with VEGFR-2 in tissue samples of metastatic prostate tumors from patients.

Agar↗

PubMed2003

Metastatic knee.

Explore the source record for details and available documents.

Adenocarcinoma↗

PubMed2003

Initial evaluation of Cyberknife technology for extracorporeal renal tissue ablation.

OBJECTIVES: To determine whether Cyberknife technology can be applied to renal tissue safely and effectively. The goal was to achieve the high efficacy of a surgical treatment, with the low morbidity of a noninvasive intervention. METHODS: The Cyberknife is a frameless, image-guided radiosurgical device. This innovative extracorporeal treatment combines a linear accelerator mounted on a highly maneuverable robotic arm. The Cyberknife is unique in that it divides the high-dose radiation necessary to ablate the lesion completely into up to 1200 beams. Each one of these beams of radiation has a significantly reduced dose. Therefore, the individual dose of each beam is essentially benign to the pathway and surrounding tissue. However, at the focal point of these beams, the dose is additive, and the desired ablative dose is attained. Predetermined "lesions" in 16 kidneys were treated in vivo in the porcine model. Complete treatment was accomplished in one session per animal, with no complications. Gross and histologic evaluations were completed at 4, 6, or 8 weeks. RESULTS: The degree of radiation changes correlated with longer treatment intervals. After 8 weeks, the lesions showed complete fibrosis. The zones of complete fibrosis were characterized by dense, paucicellular connective tissue completely devoid of all normal kidney elements, including tubules and glomeruli. CONCLUSIONS: This initial preclinical evaluation of the Cyberknife for extracorporeal renal tissue ablation appears to be very promising and demonstrated its ability to ablate a targeted area precisely and completely with relative sparing of the surrounding tissue. This innovative technology introduces an exciting approach as a potential treatment option of renal masses in the future.

Animals↗

PubMed2003

Ureteral tissue balloon expansion for laparoscopic bladder augmentation: survival study.

BACKGROUND AND PURPOSE: The search for the perfect urinary bladder substitute continues. Despite their inherent limitations, intestinal segments remain the commonest material for bladder reconstruction. The ureter, with its transitional epithelium, may be the ideal tissue to augment the bladder. Ikeguchi et al reported the feasibility of chronic ureteral balloon expansion by open surgery (J Urol 1998;159:1665). Herein, we propose a completely minimally invasive approach to balloon overdilate a segment of juxtavesical ureter incrementally and to use this in-line tissue-expanded ureteral patch to augment the bladder laparoscopically. MATERIALS AND METHODS: In five female pigs, a novel ureteral expansion balloon device (Microvasive, MA) was inserted percutaneously and advanced antegrade into the juxtavesical ureter. The device has two channels: one for balloon inflation and the other for draining the kidney. After progressive ureteral expansion over a 3- to 4-week period, laparoscopic augmentation ureterocystoplasty was performed. Animals were euthanized at 15 days (N = 1), 1 month (N = 1), 2 months (N = 1), and 3 months (N = 2). RESULTS: Percutaneous balloon device placement was technically successful in all five cases (mean operating room time 52 minutes). The mean volume of the tissue-expanded ureter at 1, 2, and 3 weeks was 12.9 cc, 60.3 cc, and 171.8 cc, respectively. Laparoscopic augmentation ureterocystoplasty with (N = 3) or without (N = 2) concomitant subtotal cystectomy was technically successful in all five cases without any open conversion. The mean operative time was 126.5 minutes, and the mean blood loss was 29 mL. Postoperative complications consisted of one case each of pyelonephritis and ureteral stricture. At autopsy, the mean capacity of the bladder was 574 mL, and the P(ves) at maximum capacity was 14 cm H(2)O. Histologic examination of the tissue-expanded ureter revealed regenerated transitional epithelium and muscle hypertrophy. CONCLUSIONS: Chronic ureteral tissue expansion can be carried out safely and efficaciously. The expanded tissue is thick, healthy, and vascular, with histologic features of normal transitional epithelium and muscle hypertrophy and hyperplasia. This expanded ureteral tissue can be used to augment the bladder with laparoscopic techniques. Such augmented bladders do not show significant shrinkage and possess urodynamic characteristic of normal capacity and normal compliance over a follow-up of 3 months.

Anastomosis, Surgical↗

PubMed2003

Spinal metastasis as the initial manifestation of a nonsecretory glucagonoma.

Glucagonomas are rare functional endocrine tumors of the pancreas that classically present with symptoms of glucagon excess, including rash, hyperglycemia, diarrhea, and weight loss. Metastatic disease at presentation is common but is often limited to the liver and regional lymph nodes. We describe an unusual case of a patient with glucagonoma who presented with a pathologic vertebral fracture. This tumor had no evidence of active hormone secretion but tested positive for glucagon by immunohistochemical staining.

Adult↗

PubMed2003

New advances transform the management of women with abnormal pap tests.

New advances in Papanicolaou test technology, human papillomavirus DNA testing, and revisions in the Bethesda terminology for cervical cytology have transformed the management of abnormal Pap tests. This approach has been validated by a recent randomized clinical trial, and in some instances can reduce the number of colposcopies by 50%.

Adult↗

PubMed2002

Preoperative combined nested reverse transcriptase polymerase chain reaction for prostate-specific antigen and prostate-specific membrane antigen does not correlate with pathologic stage or biochemical failure in patients with localized prostate cancer undergoing radical prostatectomy.

PURPOSE: We report a prospective study examining the ability of preoperative nested reverse transcriptase polymerase chain reaction (RT-PCR) for prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSM) to predict pathologic stage and biochemical recurrence in patients with clinically localized prostate cancer treated with radical prostatectomy. PATIENTS AND METHODS: One hundred forty-one patients were entered onto the study. Preoperative evaluation included clinical T stage, serum PSA, biopsy Gleason score, and serum RT-PCR for PSA/PSM. Univariate and multivariate logistic regression models, Kaplan-Meier estimates, and Cox proportional hazards modeling were used to identify predictors of pathologic stage and biochemical failure. RESULTS: Seventy-three patients (51.8%) were RT-PCR positive for PSA, PSM, or both. In the multivariate logistic regression model, only initial PSA was an independent predictor of pathologic stage as defined by organ-confined disease (odds ratio [OR], 1.06; 95% confidence interval [CI], 1.00 to 1.13; P =.026) or organ-/specimen-confined disease (OR, 1.09; 95% CI, 1.02 to 1.16; P =.009). Overall Kaplan-Meier biochemical relapse-free survival (bRFS) was 85% at 59 months. Multivariate analysis of predictors for bRFS with the Cox proportional hazards model indicated that only initial PSA (OR, 1.05; 95% CI, 1.02 to 1.09; P =.004) and biopsy Gleason score (OR, 3.57; 95% CI, 1.37 to 9.58; P =.009) were independent predictors of biochemical failure. RT-PCR status did not predict pathologic stage or biochemical failure. Repeat analysis excluding 27 patients who received preoperative androgen-deprivation therapy did not change the results. CONCLUSION: Combined nested RT-PCR for PSA and PSM is not an independent predictor of pathologic stage or biochemical failure in patients with localized prostate cancer undergoing radical prostatectomy. This assay has no clinical utility in this patient population.

Antigens, Surface↗