Larger urethral catheter size leads to fossa navicularis stricture formation in robotic radical prostatectomy

Fossa navicularis strictures following radical prostatectomy are reported infrequently. We recently experienced a series of fossa strictures following robotic-assisted laparoscopic prostatectomy (RLP). We describe herein our experience to prevent fossa strictures and to determine its etiologic factors. From June 2002 to May 2006, 424 patients underwent robotic-assisted laparoscopic prostatectomy with the da Vinci surgical system. Fossa strictures were diagnosed based on the acute onset of obstructive voiding symptoms and bougie calibration. During our series, we switched from the intra-operative use of an 18 French (F) catheter to that of a 22 F one to avoid inadvertent stapling of the urethra when dividing the dorsal venous complex. After we observed a high incidence of fossa strictures, we reverted back to 18 F catheters during surgery. All patients had an 18 F catheter indwelling for 1 week after surgery. Parameters were evaluated using Fisher’s exact test and Student’s t-test for means. The 18 F catheter group of patients (n = 293) developed one fossa stricture, whereas the 22 F catheter group (n = 131) developed nine fossa strictures (P < 0.01). The fossa stricture rate in the 18 F group was 0.3% versus 6.9% in the 22 F group. The two groups had no differences in age, body mass index, cardiovascular disease, American Urological Association symptom score, urinary bother score, preoperative prostate-specific antigen, operative time, estimated blood loss, cautery use, prostate size, or catheterization time. Based on these results, a larger urethral catheter size – 20 F versus 18 F – during the intra-operative dissection would appear to increase the risk for fossa stricture by more than 20-fold. Statement of disclosure Dr. Thomas Ahlering is a meeting participant and lecturer for Intuitive Surgical Corp. The other authors have no direct or indirect commercial financial incentives associated with publishing the article. No research or project support funding was received.     

Suppression of acute lymphoblastic leukemia by the human wild-type p53 gene.

Independent mutations in both alleles of the p53 tumor suppressor gene are a frequent finding in human T-cell acute lymphoblastic leukemia (T-ALL) cell lines and in the cells of some T-ALL patients in relapse. One major goal of studying the status of p53 (and other tumor suppressor genes) in human cancer is to facilitate the suppression of the tumorigenic phenotype through the restoration of the expression of the wild-type allele. While the efficient insertion of a suppressor into all cells of solid/metastatic human tumors may at present be impossible, insertion into leukemia cells may be feasible due to the accessibility of the leukemia cells in the body. To examine the feasibility of suppressing the tumorigenicity of human T-leukemia cells, the human T-ALL cell line Be-13, which lacks endogenous p53 protein, was infected with a recombinant retrovirus encoding the wild-type allele of human p53 (hwtp53). Expression of p53 reduced the growth rate of infected Be-13 cells in vitro, suppressed colony formation in methylcellulose cultures, and abrogated their tumorigenic phenotype in nude mice in vivo. These results suggest that suppression of the leukemic phenotype of relapse T-ALL-derived Be-13 cells is feasible. Acute leukemia cell suppression via high-efficiency infection with retroviruses encoding wtp53 may be feasible and beneficial in T-ALL cases as part of a bone marrow transplantation regimen in an effort to reduce the frequency of posttransplantation relapse.     

Parathyroid hormone regulation of proline uptake by cultured neonatal mouse osteoblastlike cells

Regulation of proline uptake by the synthetic amino-terminal fragment of bovine parathyroid hormone [bPTH-(1-34)] has been studied in confluent primary cultures of osteoblastlike cells isolated from neonatal mouse calvaria. The initial velocity of proline transport was increased by 85% in cultures treated with 24 nM bPTH-(1-34) for 6 h. Cycloheximide, at a concentration that inhibited protein synthesis by 97%, did not prevent this effect. However, adding the inhibitor during the first 1-2 h of hormone treatment did significantly reduce its magnitude. Exposure of cells to the inhibitor alone caused a time-dependent decrease in the basal rate of proline uptake. In the absence of protein synthesis, the maximal velocity (Vmax) of transport was 60% greater in cultures treated with 24 nM bPTH-(1-34) than in controls. The concentration of proline at which half-maximal transport occurred (Km) was unchanged. In cultures treated with cycloheximide alone, proline transport decreased as a first-order exponential with a half-life of 250-280 min. Parathyroid hormone significantly reduced this decline, increasing the half-life of proline transport activity about fourfold. These effects were duplicated by 1 mM DBcAMP. It is concluded that bPTH-(1-34) increases proline transport in osteoblastlike cells by decreasing the degradation of amino acid transport system A proteins. The hormone may also affect the synthesis of these molecules. These effects appear to be mediated by cAMP.     

A new immune-competent animal model of mucosally derived squamous cell carcinoma.

OBJECTIVES: To develop an immune-competent animal model for mucosally derived squamous cell carcinoma (SCCA). STUDY DESIGN: Fifteen Fischer 344 rats were inoculated with 1, 2, 5, 10, or 20 x 10(6) FAT7 cells in their flanks. The animals were observed for tumor growth and metastasis. RESULTS: All animals developed tumors that grew exponentially. Pulmonary metastases developed in all animals and 13% developed lymph node metastases. CONCLUSION: The FAT7 flank tumor in Fischer 344 rats is a new animal model that closely resembles the behavior of human mucosal head and neck cancer. SIGNIFICANCE: The existence of an immune-competent, mucosally derived, and reliable animal model of SCCA that somewhat resembles human head and neck SCCA gives the opportunity to perform immune-modulating experiments on head and neck cancer in these animals. EBM rating: B-3.     

Problems with a ‘target’ approach to access in primary care: a qualitative study

We report an analysis of the qualitative phase of a study of patients' and carers' views of primary care services, focusing on their experiences of access to face-to-face general practitioner (GP) consultations during the period when new access policies were being implemented. Practices interpreted the new policy in various ways; restricted interpretations, including restriction of access to telephone booking, could cause distress to patients. Patients and carers welcomed flexible interpretations of the policy that offered choice, such as a choice of GP, or of booking in advance.     

Electron bolus design for radiotherapy treatment planning: bolus design algorithms.

Computer algorithms to design bolus for electron beam radiotherapy treatment planning were investigated. Because of the significant electron multiple scatter, there is no unique solution to the problem of bolus design. However, using a sequence of operators, a bolus can be designed that attempts to meet three important criteria: adequate dose delivery to the target volume, avoidance of critical structures, and dose homogeneity within the target volume. Initial calculation of bolus shape was based upon creation operators forcing either the physical or the effective depths of the distal surface of the target volume to a specified value. Modification operators were then applied to the bolus to alter the shape to better meet the design criteria. Because the operators each address a single dosimetric issue, they can often adversely affect some other attribute of the dose distribution. In addition, an extension operator is used to design the bolus thickness outside the target volume. Application of these operators is therefore carried out in certain sequences and each may be used more than once in the design of a particular bolus. The effects of these operators on both the bolus and the resulting dose distribution are investigated for test geometries and patient geometries in the nose, parotid, and paraspinal region.