Benjamin N. Breyer

Osteogenic activity of the fourteen types of human bone morphogenetic proteins (BMPs).

Background:Bone morphogenic proteins (BMPs) are known to promote osteogenesis, and clinical trials are currently underway to evaluate the ability of certain BMPs to promote fracture-healing and spinal fusion. The optimal BMPs to be used in different clinical applications have not been elucidated, an

Potential use of Sox9 gene therapy for intervertebral degenerative disc disease.

Study Design. A new recombinant adenoviral vector expressing Sox9, a chondrocyte-specific transcription factor, was tested in a chondroblastic cell line and primary human intervertebral disc cells in vitro. Direct infection of intervertebral disc cells then was assessed in a rabbit model. Objectives. To deliver a potentially therapeutic viral vector expressing Sox9 to degenerative human and rabbit intervertebral discs cells, and to assess the effect of Sox9 expression on Type 2 collagen production. Summary of the Background Data. The concentration of competent Type 2 collagen, an essential constituent of the healthy nucleus pulposus, declines with intervertebral disc degeneration. Recent studies suggest that Sox9 upregulates Type 2 collagen production. Interventions that augment Type 2 collagen production by intervertebral disc cells may represent a novel therapeutic method for patients with degenerative disc disease. Methods. Adenoviral delivery vectors expressing Sox9 and green fluorescent protein were constructed using the AdEasy system. The chondroblastic cell line, HTB-94, and cultured human degenerated intervertebral disc cells were infected with the vectors. Reverse transcriptase-polymerase chain reaction and immunohistochemical analyses were performed to document increased Type 2 collagen expression. The AdSox9 virus then was injected directly into the intervertebral discs of three rabbits. After 5 weeks, the injected discs were evaluated histologically. Results. The AdSox9 virus efficiently transduced HTB-94 cells and degenerated human disc cells. Western blot analysis confirmed increased Sox9 production. Increased Type 2 collagen production was demonstrated in infected HTB-94 and human disc cells using both reverse transcriptase-polymerase chain reaction and immunohistochemical staining. In the rabbit model, cells infected with AdSox9 maintained a chondrocytic phenotype, and the architecture of the nucleus pulposus was preserved over a 5-week study period compared to control discs. Conclusions. A novel adenoviral vector efficiently increased Sox9 and Type 2 collagen synthesis in cultured chondroblastic cells and human degenerated disc cells. In a rabbit model, sustained Sox9 production preserved the histologic appearance of the nucleus pulposus cells in vivo. These findings suggest a potential role for Sox9 gene therapy in the treatment of human degenerative disc disease.

Cytoplasmic and/or nuclear accumulation of the β‐catenin protein is a frequent event in human osteosarcoma

The molecular events that precede the development of osteosarcoma, the most common primary malignancy of bone, are unclear, and concurrent molecular and genetic alterations associated with its pathogenesis have yet to be identified. Recent studies suggest that activation of β‐catenin signaling may play an important role in human tumorigenesis. To investigate the potential role of β‐catenin deregulation in human osteosarcoma, we analyzed a panel of 47 osteosarcoma samples for β‐catenin accumulation using immunohistochemistry. Potential activating mutations were investigated by sequencing exon 3 of the β‐catenin gene in genomic DNA isolated from tumor samples. Our findings revealed cytoplasmic and/or nuclear accumulation of β‐catenin in 33 of 47 samples (70.2%); however, mutation analysis failed to detect any genetic alterations within exon 3, suggesting that other regulatory mechanisms may play an important role in activating β‐catenin signaling in osteosarcoma. In our survival analysis, β‐catenin deregulation conferred a hazard ratio of 1.05, indicating that β‐catenin accumulation does not appear to be of prognostic value for osteosarcoma patients. When analyzed against other clinicopathologic parameters, β‐catenin accumulation correlated only with younger age at presentation (26.4 vs. 39.8 years). Nevertheless, our results demonstrate that the deregulation of β‐catenin signaling is a common occurrence in osteosarcoma that is implicated in the pathogenesis of osteosarcoma.

Multivariate Analysis of Risk Factors for Long-Term Urethroplasty Outcome

PURPOSE We studied the patient risk factors that promote urethroplasty failure. MATERIALS AND METHODS Records of patients who underwent urethroplasty at the University of California, San Francisco Medical Center between 1995 and 2004 were reviewed. Cox proportional hazards regression analysis was used to identify multivariate predictors of urethroplasty outcome. RESULTS Between 1995 and 2004, 443 patients of 495 who underwent urethroplasty had complete comorbidity data and were included in analysis. Median patient age was 41 years (range 18 to 90). Median followup was 5.8 years (range 1 month to 10 years). Stricture recurred in 93 patients (21%). Primary estimated stricture-free survival at 1, 3 and 5 years was 88%, 82% and 79%. After multivariate analysis smoking (HR 1.8, 95% CI 1.0-3.1, p = 0.05), prior direct vision internal urethrotomy (HR 1.7, 95% CI 1.0-3.0, p = 0.04) and prior urethroplasty (HR 1.8, 95% CI 1.1-3.1, p = 0.03) were predictive of treatment failure. On multivariate analysis diabetes mellitus showed a trend toward prediction of urethroplasty failure (HR 2.0, 95% CI 0.8-4.9, p = 0.14). CONCLUSIONS Length of urethral stricture (greater than 4 cm), prior urethroplasty and failed endoscopic therapy are predictive of failure after urethroplasty. Smoking and diabetes mellitus also may predict failure potentially secondary to microvascular damage.

Adenoviral Vector-Mediated Gene Transfer for Human Gene Therapy

Human gene therapy promises to change the practice of medicine by treating the causes of disease rather than the symptoms. Since the first clinical trial made its debut ten years ago, there are over 400 approved protocols in the United States alone, most of which have failed to show convincing data of clinical efficacy. This setback is largely due to the lack of efficient and adequate gene transfer vehicles. With the recent progress in elucidating the molecular mechanisms of human diseases and the imminent arrival of the post genomic era, there are increasing numbers of therapeutic genes or targets that are available for gene therapy. Therefore, the urgency and need for efficacious gene therapies are greater than ever. Clearly, the current fundamental obstacle is to develop delivery vectors that exhibit high efficacy and specificity of gene transfer. Recombinant adenoviruses have provided a versatile system for gene expression studies and therapeutic applications. Of late, there has been a remarkable increase in adenoviral vector-based clinical trials. Recent endeavors in the development of recombinant adenoviral vectors have focused on modification of virus tropism, accommodation of larger genes, increase in stability and control of transgene expression, and down-modulation of host immune responses. These modifications and continued improvements in adenoviral vectors will provide a great opportunity for human gene therapy to live up to its enormous potential in the second decade.

Tyrosine kinase inhibitor STI-571/gleevec down-regulates the β-catenin signaling activity

Beta-Catenin is a critical transducer of the Wnt signal pathway and plays an important role in many developmental and cellular processes. Deregulation of beta-catenin signaling has been observed in a broad range of human tumors. In this report, we investigated whether tyrosine kinase inhibitor STI-571 could inhibit the beta-catenin signaling activity and hence suppress cell proliferation. Our results demonstrated that STI-571 effectively inhibited the constitutive activity of beta-catenin signaling in human colon cancer cells as well as the Wnt1-induced activation of beta-catenin signaling in HOS, HTB-94, and HEK 293 cells. Furthermore, STI-571 was shown to effectively suppress the proliferation of human colon cancer cells. Finally, we demonstrated that the Wnt1-mediated activation of a GAL4-beta-catenin heterologous transcription system was effectively inhibited by STI-571. Thus, our findings suggest that tyrosine phosphorylation may play an important role in regulating beta-catenin signaling activity, and inhibition of this signaling pathway by STI-571 may be further explored as an important target for alternative/adjuvant treatments for a broader range of human cancer.

Minimally Invasive Endovascular Techniques to Treat Acute Renal Hemorrhage

PURPOSE We evaluated the effectiveness of endovascular therapy for severe renal hemorrhage. MATERIALS AND METHODS We retrospectively reviewed cases compiled from the trauma database, billing records and interventional radiology logs at our institution from 1990 to 2007. Technical success was defined as the cessation of bleeding after angiographic embolization. Clinical success was defined as the absence of recurrent hematuria without the need for additional embolization. RESULTS A total of 26 patients underwent angiography and endovascular treatment for renal hemorrhage. Mean patient age was 42 years (median 37, range 7 to 70). There were 20 males and 6 females. Mean clinical followup was 11.7 months. The mechanisms of injury were iatrogenic in 6 cases (renal biopsy in 5 and post-percutaneous nephrostomy placement in 1), trauma in 16 (blunt in 10 and penetrating in 6) and spontaneous rupture of a renal mass in 4. At presentation 16 patients (62%) were hemodynamically stable, while 10 (38%) were in shock. A total of 11 patients (42%) presented with gross hematuria, 7 (27%) had microscopic hematuria and 8 (31%) had no evidence of hematuria. A total of 16 patients (62%) had kidney injuries alone, while 10 (38%) also had significant concurrent injuries. Treatment failed in all 5 grade 5 acute renal injuries (100%) caused by external trauma. Technical and clinical success was achieved in 22 (85%) and 17 patients (65%), respectively. CONCLUSIONS Superselective embolization therapy for renal trauma provides an effective and minimally invasive means to stop bleeding. Overall our complication rate was minimal. Most renal traumas, including most grade 4 injuries, were effectively managed by conservative therapy. Embolization proved effective for grade 4 renal trauma for which conservative therapy failed. In our series embolization failed when applied to grade 5 injuries.

Incidence of bladder neck contracture after robot‐assisted laparoscopic and open radical prostatectomy

Study Type – Therapy (case series)
Level of Evidence 4

Erectogenic and Neurotrophic Effects of Icariin, a Purified Extract of Horny Goat Weed (Epimedium spp.) In Vitro and In Vivo

INTRODUCTION Epimedium species (aka horny goat weed) have been utilized for the treatment of erectile dysfunction in Traditional Chinese Medicine for many years. Icariin (ICA) is the active moiety of Epimedium species. AIM To evaluate the penile hemodynamic and tissue effects of ICA in cavernous nerve injured rats. We also studied the in vitro effects of ICA on cultured pelvic ganglia. METHODS Rats were subjected to cavernous nerve injury and subsequently treated for 4 weeks with daily gavage feedings of a placebo solution of normal saline and Dimethyl sulfoxide (DMSO) vs. ICA dissolved in DMSO at doses of 1, 5, and 10 mg/kg. A separate group underwent a single dose of ICA 10 mg/kg 2 hours prior to functional testing. Functional testing with cavernous nerve stimulation and real-time assessment of intracavernous pressure (ICP) was performed at 4 weeks. After functional testing, penile tissue was procured for immunohistochemistry and molecular studies. In separate experiments, pelvic ganglia were excised from healthy rats and cultured in the presence of ICA, sildenafil, or placebo culture media. MAIN OUTCOME MEASURE Ratio of ICP and area under the curve (AUC) to mean arterial pressure (MAP) during cavernous nerve stimulation of subject rodents. We also assayed tissue expression of neuronal nitric oxide synthase (nNOS), eNOS: endothelial nitric oxide synthase (eNOS), calponin, and apoptosis via immunohistochemistry and Western blot. Serum testosterone and luteinizing hormone (LH) were assayed using enzyme-linked immunosorbant assay (ELISA). Differential length of neurite outgrowth was assessed in cultured pelvic ganglia. RESULTS Rats treated with low-dose ICA demonstrated significantly higher ICP/MAP and AUC/MAP ratios compared with control and single-dose ICA animals. Immunohistochemistry and Western blot were revealing of significantly greater positivity for nNOS and calponin in penile tissues of all rats treated with ICA. ICA led to significantly greater neurite length in cultured specimens of pelvic ganglia. CONCLUSION ICA may have neurotrophic effects in addition to known phosphodiesterase type 5 inhibiting effects.

Sexual Function and Depressive Symptoms among Male North American Medical Students

INTRODUCTION The role of sexuality as an association of medical student well-being has not been extensively studied. AIM We explored the relationship between depressive symptoms, sexuality, and sexual dysfunction in male North American medical students. MAIN OUTCOME MEASURE North American medical students were invited to participate in an Internet-based survey. The Center for Epidemiological Studies Depression Scale (CES-D) was utilized to screen for depressive symptoms. METHODS Subjects completed an ethnodemographic survey, a sexuality survey, and instruments for the quantification of anxiety, sexuality, and psychosocial function. Descriptive statistics, odds ratios (ORs), and logistic regression were used to analyze our data. RESULTS There were 844 male subjects with complete data on the CES-D and the Spielberger State-Trait Anxiety Index. Depressive symptoms (CES-D ≥ 16) were present in 37% of respondents and were more common in subjects with greater levels of anxiety. Subjects who were in sexual relationships and/or had frequent sexual activity were less likely to be depressed compared to other subjects. Erectile dysfunction (ED) was associated with significantly greater likelihood of depressive symptoms (OR 2.90 and 9.27 for depressive symptoms in men with mild or moderate/severe ED relative to men without ED, P < 0.01). After adjusting for ethnodemographic and sexual history factors, ED remained significantly positively associated with depressive symptoms (OR 2.87 and 6.59 for depressive symptoms in men with mild or moderate/severe ED relative to men without ED after adjustment, P ≤ 0.01). Inclusion of data related to psychosocial/relationship factors in the multivariate model eliminated the significant association between ED and depressive symptoms (OR 1.59 and 2.29 for depressive symptoms in men with mild or moderate/severe ED relative to men without ED after adjustment with the Self-Esteem and Relationship quality instrument, P > 0.05), suggesting that psychosocial factors were more strongly associated with depressive symptoms than erectile function. CONCLUSION Healthy sexuality and relationships may be protective against depressive symptoms in medical students. Attention to these factors may enhance medical student well-being.