Human Prostate (human + prostate)

Distribution by Scientific Domains

Terms modified by Human Prostate

  • human prostate cancer
  • human prostate cancer cell
  • human prostate cancer cell line
  • human prostate cancers
  • human prostate carcinoma
  • human prostate tissue
  • human prostate tumor

  • Selected Abstracts


    Effects of steroids on oxytocin secretion by the human prostate in vitro

    INTERNATIONAL JOURNAL OF ANDROLOGY, Issue 1 2004
    S. J. Assinder
    Summary Oxytocin (OT) concentrations are elevated in prostate tissue of patients with benign prostatic hyperplasia (BPH). Oxytocin specifically increases growth, 5 , -reductase activity and contractility in the prostate. In the rat prostatic OT concentrations are regulated by gonadal steroids, with androgens reducing but oestrogens increasing OT concentrations. The regulation of prostatic oxytocin in man is not understood. This study investigates the effects of gonadal steroids on oxytocin production by the human prostate. Primary explants (approx. 1 mm3) of prostate tissue from patients with BPH were incubated in Dulbecco's modified Eagle's media in the absence or presence of 10 nmol/L testosterone (T), 10 nmol/L dihydrotestosterone (DHT), T or DHT plus 100 nmol/L of the anti-androgen cyproterone acetate (CPA), 55 pmol/L diethylstilbestrol (DES), or DES plus DHT. The amount of oxytocin secreted into the media after 3 days was measured by radioimmunoassay. Testosterone and DHT significantly increased oxytocin concentrations secreted into the media from 0.86 ± 0.11 ng/g of tissue (control) to 1.51 ± 0.14 ng/g (p < 0.01) and 1.54 ± 0.13 ng/g (p < 0.05), respectively. Incubation of tissue samples with CPA resulted in oxytocin concentrations similar to control levels. Treatment with DES caused a significant increase from 1.99 ± 0.71 to 3.98 ± 1.36 ng/g (p < 0.05). A similar increase was measured in media of tissue incubated in DES plus DHT (p < 0.001). The results demonstrate that, unlike the rat where androgens decrease oxytocin, in hyperplastic human prostate tissue both androgens and oestrogens increase oxytocin. This imbalance in the regulation of oxytocin may result in promoting prostatic overgrowth in the pathogenesis of BPH. [source]


    Are primary cultures realistic models of prostate cancer?

    JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 1 2004
    Donna M. Peehl
    Abstract Primary cultures fill a unique niche among the repertoire of in vitro model systems available to investigate the biology of the normal and malignant human prostate. This review summarizes some of the properties of primary cultures, with special emphasis on two questions: are primary cultures from adenocarcinomas really comprised of cancer rather than normal cells, and do primary cultures faithfully retain characteristics of cells of origin? © 2003 Wiley-Liss, Inc. [source]


    High-field MRSI of the prostate using a transmit/receive endorectal coil and gradient modulated adiabatic localization

    JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 2 2009
    Jamie Near PhD
    Abstract Purpose To demonstrate in vivo magnetic resonance spectroscopic imaging (MRSI) of the human prostate at 4.0T using a transmit/receive endorectal coil and a pulse sequence designed specifically for this application. Materials and Methods A solid, reusable endorectal probe was designed for both radiofrequency transmission and reception. Finite difference time domain (FDTD) simulations were performed to characterize the coil's electric field distribution, and temperature measurements were performed in a beef tissue phantom to determine the coil's safe operating limit. The localization by selective adiabatic refocusing (LASER) pulse sequence was implemented using six gradient modulated offset independent adiabatic (GOIA) pulses for very sharp, B1 -insensitive voxel localization. Results Based on the simulations and temperature measurements, the coil's safe operating limit was conservatively estimated to be 1.0W for 15 minutes. The transition width of the GOIA pulse selection profiles was only 6% of the bandwidth, compared with 22% for a specific absorption rate (SAR)-matched conventional adiabatic pulse. Using the coil and pulse sequence described here, MRSI data were successfully acquired from a patient with biopsy-proven prostate cancer, with a nominal voxel size of 0.34 cc in a scan time of 15 minutes. Conclusion This work demonstrates the safe and effective use of a transmit/receive endorectal coil for in vivo MRSI of the prostate. J. Magn. Reson. Imaging 2009;30:335,343. © 2009 Wiley-Liss, Inc. [source]


    Fast acquisition-weighted three-dimensional proton MR spectroscopic imaging of the human prostate,

    MAGNETIC RESONANCE IN MEDICINE, Issue 1 2004
    Tom W.J. Scheenen
    Abstract The clinical application of 3D proton spectroscopic imaging (3D SI) of the human prostate requires a robust suppression of periprostatic lipid signal contamination, minimal intervoxel signal contamination, and the shortest possible measurement time. In this work, a weighted elliptical sampling of k -space, combined with k -space filtering and pulse repetition time (TR) reduction minimized lipid signals, intervoxel contamination, and measurement time. At 1.5 T, the MR-visible prostate metabolites citrate, creatine, and choline can now be mapped over the entire human prostate with uncontaminated spherical voxels, with a volume down to 0.37 cm3, in measurement times of 7,15 min. Magn Reson Med 52:80,88, 2004. © 2004 Wiley-Liss, Inc. [source]


    Androgen-independent expression of adrenomedullin and peptidylglycine ,-amidating monooxygenase in human prostatic carcinoma

    MOLECULAR CARCINOGENESIS, Issue 1 2003
    Nuria Jiménez
    Abstract Most of the locally advanced and metastatic prostate carcinomas (PCs) treated with antiandrogenic therapy eventually become refractory to this treatment. Locally produced factors may control prostate tumor biology after androgen withdrawal. Adrenomedullin (AM) is expressed in the prostate and could control cell growth in androgen-independent conditions. AM needs to be amidated by the enzyme peptidylglycine ,-amidating monooxygenase (PAM) to become fully active. The objective of the present study was to analyze whether the expression of preproadrenomedullin (preproAM) and PAM in PC is regulated by androgens. For this purpose, human in vitro and in vivo PC models were grown in the presence or absence of androgens, and the expression of AM and PAM was examined by immunohistochemistry, Western blotting, RT-PCR, and Northern blotting. Furthermore, immunohistochemical analysis of AM in clinical specimens was performed to test if its expression is related to Gleason score and antiandrogenic therapy. In PC cell lines and xenografts, mRNA and protein AM levels were similar in the presence or absence of androgens. PAM expression seemed to be induced by androgen-withdrawal. Our results in clinical samples showed no relationship between AM expression and Gleason score or antiandrogenic treatment. In conclusion, our results demonstrate that preproAM and PAM expression in the human prostate is androgen-independent. In addition, we also report for the first time the expression of a novel PAM transcript in PC, which has not been previously described in other tissues. © 2003 Wiley-Liss, Inc. [source]


    An evaluation of PCR primer sets used for detection of Propionibacterium acnes in prostate tissue samples

    THE PROSTATE, Issue 14 2008
    Karen S. Sfanos
    Abstract BACKGROUND Multiple studies have now shown that Propionibacterium acnes can be cultured from post-prostatectomy derived prostate tissue samples. In contrast, both universal eubacterial 16S rDNA PCR and P. acnes -specific 16S rDNA PCR have failed to detect this organism at a frequency similar to that of bacterial culture. A potential explanation for this discrepancy, proposed by Cohen et al., involves mismatches in 16S rDNA primer sets used for bacterial detection. METHODS The sensitivity of both a previously published P. acnes -specific primer set containing a potential mismatch and a new primer set with no mismatches was determined. Both primer sets were used to interrogate two sets of DNA samples derived from post-prostatectomy prostate tissues that differed in the level of sterile precautions maintained during tissue collection. RESULTS The number of P. acnes positive samples was associated with the sterility of the sample collection process. In all instances, positive samples were determined to reflect low cell numbers (<10 CFU). CONCLUSIONS Although the results of previous studies have shown that P. acnes is not the only organism potentially present in the prostates of prostate cancer patients, mismatches in PCR primer sets may have also influenced the sensitivity of P. acnes detection. When using PCR in determining the presence of P. acnes in the human prostate, care should be taken to establish the potential influence of exogenous contamination and, due to the sensitivity of the assay, samples exposed to the urethra during the collection process (prostatic secretions, TURP specimens) should not be used. Prostate 68: 1492,1495, 2008. © 2008 Wiley-Liss, Inc. [source]


    Androgen receptor or estrogen receptor-, blockade alters DHEA-, DHT-, and E2 -induced proliferation and PSA production in human prostate cancer cells

    THE PROSTATE, Issue 11 2007
    Julia T. Arnold
    Abstract BACKGROUND Dehydroepiandrosterone (DHEA) is an endogenous steroid that is metabolized to androgens and/or estrogens in the human prostate. DHEA levels decline with age, and use of DHEA supplements to retard the aging process is of unproved effectiveness and safety. LNCaP and LAPC-4 prostate cancer cells were used to determine whether DHEA-modulated proliferation and prostate specific antigen (PSA) production were mediated via the androgen receptor (AR) and/or ER,. METHODS Cells were treated with DHEA, DHT, or E2 and antagonists to AR (Casodex®-bicalutamide) or ER (ICI 182,780) or siRNA to the respective receptors. Proliferation was assessed by MTT assay and PSA mRNA and protein secretion were measured by quantitative real-time PCR and ELISA. Associations of AR and ER, were analyzed by co-immunoprecipitation studies and fluorescent confocal microscopy. RESULTS DHEA-, T-, and E2 -induced proliferation of LNCaP cells was blunted by Casodex but not by ICI treatment. In LNCaP cells, Casodex and ICI suppressed hormone-induced PSA production. In LAPC-4 cells, DHT-stimulated PSA mRNA was inhibited by Casodex and ICI, and the minimal stimulation by DHEA was inhibited by ICI. Use of siRNAs confirmed involvement of AR and ER, in hormone-induced PSA production while AR-ER, co-association was suggested by immunoprecipitation and nuclear co-localization. CONCLUSIONS These findings support involvement of both AR and ER, in mediating DHEA-, DHT-, and E2 -induced PSA expression in prostate cancer cells. Prostate 67: 1152,1162, 2007. © 2007 Wiley-Liss, Inc. [source]


    Secretagogin is a new neuroendocrine marker in the human prostate

    THE PROSTATE, Issue 5 2007
    Katja Adolf
    Abstract Background Neuroendocrine (NE) differentiation in prostate cancer (PCa), promoted by NE cell secreted products, appears to be associated with tumor progression, poor prognosis, and hormone-refractory disease. We recently reported secretagogin, a hexa-EF-hand Ca2+ binding protein, as a novel NE marker in carcinoid tumors of the lung and the gastrointestinal tract. The present study analyzes the expression of secretagogin in normal and malign prostate tissue. Methods We analyzed immunoreactivity for secretagogin, chromogranin A (CgA), neuron specific enolase (NSE), and synaptophysin (SYN) in consecutive sections from 87 formalin-fixed paraffin-embedded (FFPE) benign hyperplastic (n,=,10) and prostate adenocarcinoma (n,=,77) specimens. The intracellular distribution of secretagogin, CgA, and NSE was examined by confocal fluorescent microscopy, and we characterized secretagogin in eight samples by Western blotting. Results Secretagogin is cytoplasmic and nuclear expressed in NE and NE differentiated cells, and to a lesser extent in epithelial cells, in the benign prostate and prostate adenocarcinoma cells. Secretagogin stained 82% (46/56) of benign and 71% (48/68) of prostate adenocarcinomas and co-localized with the NE markers CgA and NSE. The expression of secretagogin is significantly correlated to CgA (P,<,0.001) and NSE (P,<,0.048) in prostate adenocarcinoma and to CgA in normal epithelium (P,<,0.028). Conclusions Secretagogin is a novel NE marker in the prostate with more extended immunoreactivity compared to the NE markers CgA, SYN, and NSE. Secretagogin is widely expressed in prostatic adenocarcinoma as opposed to adenocarcinomas in other organs. Prostate 67: 472,484, 2007. © 2007 Wiley-Liss, Inc. [source]


    Comparative study of PSMA expression in the prostate of mouse, dog, monkey, and human,

    THE PROSTATE, Issue 9 2006
    Saurabh Aggarwal
    Abstract BACKGROUND Intraprostatic PSMA targeted prodrugs/protoxins are under development in our laboratory. Future toxicologic studies of these therapies require identification of animal models that express PSMA within the prostate. METHOD PSMA enzymatic activity and protein expression was determined. PSMA expression in the prostates of mouse, dog, and monkey were compared to humans by real-time PCR analysis. RESULTS No substrate hydrolysis was observed in dog or monkey prostate homogenates. Monkey prostate was negative for PSMA protein expression. No significant PSMA mRNA levels were detected by real time PCR in mouse, dog, or monkey prostate tissue compared to PSMA negative tissues. CONCLUSIONS PSMA is not expressed in any significant amount in the prostates of mouse, beagle dog, or macaque monkeys in this study but is expressed in high levels by human prostate. These non-human species, therefore, are not suitable toxicologic models to assess prostate damage from PSMA-activated intraprostatic prodrug/protoxin therapies. Prostate 66: 903,910, 2006. © 2006 Wiley-Liss, Inc. [source]


    Small G-protein RhoE is underexpressed in prostate cancer and induces cell cycle arrest and apoptosis

    THE PROSTATE, Issue 4 2005
    Jasmin Bektic
    Abstract BACKGROUND RhoE/Rnd3, a recently described novel member of the Rho GTPases family, was discussed as a possible antagonist of the RhoA protein that stimulates cell cycle progression and is overexpressed and/or overactivated in prostate cancer. We investigated the expression of RhoE and its role in cell cycle regulation and apoptosis in the human prostate. METHODS RhoE expression in cell lines and tissue specimens was assessed by immunoblot analysis, real-time PCR (RT-PCR), and immunohistochemistry. To elucidate RhoE effects on the prostate, RhoE was cloned and overexpressed in DU-145 prostate cancer. Cell cycle modulation and apoptosis was investigated by immunoblot and FACS analysis. RESULTS Immunoblot analysis showed a strong RhoE signal in both, benign epithelial and stromal cells. In contrast, almost no protein was detected in various prostate cancer cells. On RT-PCR and microarray analysis, RhoE mRNA expression was significantly reduced in malignant tissue when compared to benign samples. RhoE immunostaining was strong in benign tissue, especially in prostate epithelial cells, whereas it was minimal or absent in malignant tissue. Forced RhoE overexpression in a prostate cancer cell line inhibits the expression of two proteins essential for G2/M transition, namely CDC2 and cyclin B1, and induces G2/M arrest. In addition, apoptotic cell death as measured by a cleavage product of caspase 3 is significantly increased in RhoE-overexpressing cells. CONCLUSION In conclusion, our findings suggest RhoE as a tumor suppressor gene that is downregulatated early in the development of prostate cancer. © 2005 Wiley-Liss, Inc. [source]


    Purification of the keratan sulfate proteoglycan expressed in prostatic secretory cells and its identification as lumican

    THE PROSTATE, Issue 3 2004
    John W. Holland
    Abstract BACKGROUND Secretory epithelial cells of human prostate contain a keratan sulfate proteoglycan (KSPG) associated with the prostatic secretory granules (PSGs). The proteoglycan has not been identified, but like the PSGs, it is lost in the early stages of malignant transformation. METHODS Anion exchange and affinity chromatography were used to purify KSPG from human prostate tissue. Enzymatic deglycosylation was used to remove keratan sulfate (KS). The core protein was isolated using 2D gel electrophoresis, digested in-gel with trypsin, and identified by peptide mass fingerprinting (PMF). RESULTS The purified proteoglycan was detected as a broad smear on Western blots with an apparent molecular weight of 65,95 kDa. The KS moiety was susceptible to digestion with keratanase II and peptide N -glycosidase F defining it as highly sulfated and N-linked to the core protein. The core protein was identified, following deglycosylation and PMF, as lumican and subsequently confirmed by Western blotting using an anti-lumican antibody. CONCLUSIONS The KSPG associated with PSGs in normal prostate epithelium is lumican. While the role of lumican in extracellular matrix is well established, its function in the prostate secretory process is not known. It's potential to facilitate packaging of polyamines in PSGs, to act as a tumor suppressor and to mark the early stages of malignant transformation warrant further investigation. © 2004 Wiley-Liss, Inc. [source]


    Interstitial cells in the human prostate: A new therapeutic target?

    THE PROSTATE, Issue 4 2003
    Frank Van der Aa
    Abstract BACKGROUND Interstitial cells have been described in different human organs, including gut and bladder. In the gut they function as pacemaker cells, generating slow wave potentials. Absence or defects in these cells result in motility disorders. In the bladder these cells express the vanilloid receptor and may contribute to the working mechanism of vanilloid therapy. Recently, slow wave potentials and interstitial cells were described in the guinea-pig prostate. In this study we describe the presence of interstitial cells in the human prostate gland. METHODS We performed immunohistochemical staining for c-kit, vanilloid receptor (VR1), cannabinoid receptor (CB1) connexin43, and neurofilament on fresh frozen tissue from 14 prostatectomy specimens. RESULTS A large number of cells with a stellate aspect were noticed under the basal layer of the prostatic duct system and in between the smooth muscle cells. They were immunoreactive for c-kit, VR1, and connexin43 but not to CB1 or neurofilament. CONCLUSIONS There is evidence for interstitial cells in the human prostate. Taken together their topography and immunohistochemical characterization, the discovery of slow wave potentials in guinea pig prostate and the knowledge of interstitial cells in other organs, interstitial cells are likely to be involved in normal prostate physiology. Prostate 56: 250,255, 2003. © 2003 Wiley-Liss, Inc. [source]


    Reduction of human prostate tumor vascularity by the ,1-adrenoceptor antagonist terazosin

    THE PROSTATE, Issue 2 2001
    Kaspar Keledjian
    Abstract BACKGROUND We previously demonstrated that the quinazoline-derived a1-adrenoceptor antagonists doxazosin and terazosin suppress prostate cancer growth via apoptosis induction. The aim of this study was to determine the potential effect of a1-adrenoceptor antagonists on tumor vascularity of the human prostate. METHODS A total of 34 men with benign prostatic hyperplasia (BPH) who have been on terazosin treatment (for the obstructive symptoms) were pathologically diagnosed with prostate cancer following surgery. These patients were stratified according to the length of treatment periods with terazosin into two groups, 1 week,6 months, and 6,17 months. The control group consisted of prostatectomy specimens from 25 untreated prostate cancer patients undergoing surgery for localized disease. Formalin-fixed, paraffin-embedded prostate specimens were analyzed for apoptosis (TUNEL assay), cell proliferation (Ki-67), microvessel density (MVD) (von Willebrand factor/Factor VIII), vascular endothelial growth factor (VEGF) expression, and prostate specific antigen (PSA) immunoreactivity. RESULTS A significant induction of apoptosis was observed among cancerous prostatic epithelial cells in the terazosin-treated, as compared to the untreated prostate cancer specimens, while there was no significant change in the proliferative index of the same tumor cell populations after treatment. Furthermore, terazosin resulted in a significant decrease in prostate tissue MVD compared with the untreated group (P,<,0.01), that correlated with the increased apoptotic index of the cancerous areas. Tissue PSA expression in the prostatic tumor foci was also markedly reduced after terazosin treatment, while no significant changes in VEGF expression were detected. CONCLUSIONS These findings provide the first evidence that terazosin, a quinazoline-based a1-blocker decreases prostate tumor vascularity. Our study has significant clinical implications in identifying selected ,1-adrenoceptor antagonists as potential anti-tumor agents with apoptotic and anti-angiogenic effects in the human prostate that can be exploited for the treatment of advanced prostate cancer. Prostate 48:71,78, 2001. © 2001 Wiley-Liss, Inc. [source]


    C-type natriuretic peptide in prostate cancer

    APMIS, Issue 1 2009
    SOEREN JUNGE NIELSEN
    C-type natriuretic peptide (CNP) is expressed in the male reproductive organs in pigs. To examine whether the human prostate also expresses the CNP gene, we measured CNP and N-terminal proCNP in prostate cancer tissue extracts and performed immunohistochemical biopsy staining. Additionally, proCNP-derived peptides were quantitated in plasma from patients with prostate cancer. Blood was collected from healthy controls and patients before surgery for localized prostate cancer. Tissue extracts were prepared from tissue biopsies obtained from radical prostatectomy surgery. N-terminal proCNP, proCNP (1,50) and CNP were measured in plasma and tissue extracts. Biopsies were stained for CNP-22 and N-terminal proCNP. Tissue extracts from human prostate cancer contained mostly N-terminal proCNP [median 5.3 pmol/g tissue (range 1.0,12.9)] and less CNP [0.14 pmol/g tissue (0.01,1.34)]. Immunohistochemistry demonstrated the presence of the peptides in prostatic epithelial cells. The N-terminal proCNP concentrations in plasma were marginally lower in patients with localized prostate cancer compared with control subjects [13.8 pmol/l (11.0,17.2) vs. 15.1 pmol/l (10.4,23.2), p=0.002] but not enough to justify the use of N-terminal proCNP as a cancer marker. Further research is needed to establish whether measurement of proCNP-derived peptides may offer clinical information. [source]


    Design and Synthesis of a Gossypol Derivative with Improved Antitumor Activities

    ARCHIV DER PHARMAZIE, Issue 4 2009
    Yonghua Zhan
    Abstract A novel chemical process has been devised for the synthesis of a new derivative of gossypol, 6,7,6,,7,-tetrahydroxy-5,5,-diisopropyl-3,3,-dimethyl-[2,2']binaphthalenyl-1,4,1,,4,-tetraone (Apogossypolone). This new process has only four steps, with a shorter synthesis span, a simple purification process, and improved yield and quality. The structure of apogossypolone was characterized by 1H-nuclear magnetic resonance, 13C-nuclear magnetic resonance, mass spectroscopy, infrared spectroscopy, and elemental analysis. Cell-cytotoxicity assay demonstrates that apogossypolone is three- to six-fold more potent than the parent compound, (,)-gossypol, in inhibiting the human prostate tumor cell lines PC-3 and DU-145 as well as the human breast cancer cell line MDA-MB-231. The colony-formation assay with DU-145 cells showed that apogossypolone inhibited more than 70% of colony formation at 1 ,M, whereas (,)-gossypol at 10 ,M only inhibited less than 50% of colony formation. The results indicate that apogossypolone exerts strong antitumor activities in human prostate and breast cancer cells, and thus represents a promising cancer therapeutic. [source]


    Characterization of an anandamide degradation system in prostate epithelial PC-3 cells: synthesis of new transporter inhibitors as tools for this study

    BRITISH JOURNAL OF PHARMACOLOGY, Issue 3 2004
    Lidia Ruiz-Llorente
    The response of anandamide is terminated by a carrier-mediated transport followed by degradation catalyzed by the cloned enzyme fatty acid amidohydrolase (FAAH). In this study, we provide biochemical data showing an anandamide uptake process and the expression of FAAH in human prostate. Anandamide was accumulated in PC-3 cells by a saturable and temperature-dependent process. Kinetic studies of anandamide uptake, determined in the presence of cannabinoid and vanilloid antagonists, revealed apparent parameters of KM=4.7±0.2 ,M and Vmax=3.3±0.3 pmol min,1 (106 cells),1. The accumulation of anandamide was moderately inhibited by previously characterized anandamide transporter inhibitors (AM404, UCM707 and VDM11) but was unaffected by inhibitors of other lipid transport systems (phloretin or verapamil) and moderately affected by the FAAH inhibitor methyl arachidonyl fluorophosphonate. The presence of FAAH in human prostate epithelial PC-3 cells was confirmed by analyzing its expression by Western blot and measuring FAAH activity. To further study the structural requirements of the putative carrier, we synthesized a series of structurally different compounds 1,8 and evaluated their capacity as uptake inhibitors. They showed different inhibitory capacity in PC-3 cells, with (9Z,12Z)- N -(fur-3-ylmethyl)octadeca-9,12-dienamide (4, UCM119) being the most efficacious, with maximal inhibition and IC50 values of 49% and 11.3±0.5 ,M, respectively. In conclusion, PC-3 cells possess a complete inactivation system for anandamide formed by an uptake process and the enzyme FAAH. These results suggest a possible physiological function of anandamide in the prostate, reinforcing the role of endocannabinoid system as a neuroendocrine modulator. British Journal of Pharmacology (2004) 141, 457,467. doi:10.1038/sj.bjp.0705628 [source]


    A preliminary analysis and model of prostate injection distributions

    THE PROSTATE, Issue 4 2006
    Scott L. Chowning
    Abstract PURPOSE Understanding the internal dynamics of prostate injections, particularly injection pattern distribution is a key step to developing new therapies for prostate disease that may be best served with a direct injection approach. Due to excellent properties involving liquid contrast agents, MRI can be used for targeting and monitoring of injections into organs and tissues. MATERIALS AND METHODS Eleven intraprostatic injections were performed in vivo with canines using a custom transrectal guiding and imaging system for use in a standard 1.5 T MR scanner. In addition, 25 injections were performed on excised cadaveric human prostates, using a MedRad SpectrisÔ injector system. MRI was used to guide the injections and monitor intraparenchymal injection distribution. RESULTS T1 and T2-weighted MR images were correlated with histology to produce three-dimensional data sets that can be used to analyze trends in injection patterns. This analysis was used to develop strategies for injection prediction such as gadolinium preinjections and diffusion-weighted imaging guidance. In addition, a rough model of prostate injections is described, and a preliminary injection guide is developed that takes into account the individual clinician's goals for therapy. CONCLUSIONS MR visualization of injected therapeutic agents allows for prediction and monitoring of drug distributions, possibly improving efficacy and reducing side effects. Injection analysis and modeling may be used to assist in optimizing clinical treatments that require or would benefit from focal parenchymal injections into the prostate. © 2005 Wiley-Liss, Inc. [source]