Can autologous myoblasts be used as a potential bulking agent?

OBJECTIVE: To investigate the behaviour of donor myoblasts at the vesico-ureteric junction (VUJ) and to evaluate their potential as an autologous bulking agent, as myoblast transplantation has been shown to regenerate damaged or degenerated tissue, and it was postulated that they could be used to treat vesico-ureteric reflux. MATERIALS AND METHODS: Muscle biopsies were obtained from the lower limb muscles of 10 pigs. The quality of the cells was evaluated by electrophysiological and immunohistochemical tests. The cell membranes of myoblasts were labelled with PKH26, a fluorescent dye. Six weeks after taking of the muscle biopsies all pigs underwent cell transplantation; 30 x 10(6) cells suspended in transplantation medium (in 1-mL syringes) were injected at the VUJ, into the proximal urethra and the rhabdosphincter. At the VUJ volumes of 1 mL were injected, whereas in the urethra and rhabdosphincter small cell depots (0.1 mL) were injected. All the pigs were killed 8 weeks later, and the myoblasts and newly formed myofibres were identified using fluorescence microscopy, with a histological evaluation and investigation of potential local inflammatory reaction. RESULTS: Two to three intact layers of autologous myoblasts were found in the outer aspects of the large cell depots in the VUJ. Immunohistochemistry further showed that the myoblasts were only viable at these outermost borders of the large bulking areas, whereas necrosis with red fluorescent cell detritus was visible in the remaining central aspects of the large bulk of cells. By contrast, cells survived and formed myotubes in the wall of the proximal urethra and the rhabdosphincter where the small cell depots had been injected. CONCLUSIONS: In small depots, transplanted autologous myoblasts can survive and differentiate into myofibres, while in a large bulk of cells the vast majority of cells become necrotic. The present results show that myoblasts cannot be used for augmentation of large volumes of tissue or as a bulking agent.

A comparison of the combination of epinephrine and vasopressin with lipid emulsion in a porcine model of asphyxial cardiac arrest after intravenous injection of bupivacaine.

BACKGROUND: In a porcine model, we compared the effect of the combination of vasopressin/epinephrine with that of a lipid emulsion on survival after bupivacaine-induced cardiac arrest. METHODS: After administration of 5 mg/kg of a 0.5% bupivacaine solution i.v., ventilation was interrupted for 2 +/- 0.5 (mean +/- SD) min until asystole occurred. Cardiopulmonary resuscitation (CPR) was initiated after 1 min of untreated cardiac arrest. After 2 min of CPR, 10 animals received, every 5 min, either vasopressin combined with epinephrine or 4 mL/kg of a 20% lipid emulsion. Three minutes after each drug administration, up to three countershocks (4, 4, and 6 J/kg) were administered; all subsequent shocks with 6 J/kg. Blood for determination of the plasma bupivacaine concentration was drawn throughout the experiment. RESULTS: In the vasopressor group, all five pigs survived, whereas none of five pigs in the lipid group had restoration of spontaneous circulation (P < 0.01). There was no significant difference between groups in the plasma concentration of total bupivacaine. CONCLUSION: In this model of a bupivacaine-induced cardiac arrest, the vasopressor combination of vasopressin and epinephrine compared with lipid emulsion resulted in higher coronary perfusion pressure during CPR and survival rates.

Arginine vasopressin during sinus rhythm: effects on haemodynamic variables, left anterior descending coronary artery cross sectional area and cardiac index, before and after inhibition of NO-synthase, in pigs.

UNLABELLED: We have shown previously that arginine vasopressin (AVP) given during sinus rhythm increases mean arterial blood pressure (MAP) and left anterior descending (LAD) coronary artery cross sectional area. AVP was assumed to result in vasodilatation via activation of the endothelial nitric oxide system. The purpose of the present study was to assess the effects of AVP before and after NO-inhibition. Nine domestic pigs were instrumented for measurement of haemodynamic variables using micromanometer-tipped catheters, and measurement of LAD coronary artery cross sectional area employing intravascular ultrasound (IVUS). Haemodynamic variables, LAD coronary artery cross sectional area and cardiac output were measured at baseline, 90 s and 5, 15, and 30 min after AVP (0.4 U kg (-1) IV) before and after blockade of nitric oxide synthase with N(G)-nitro L-arginine methyl ester (L-NAME). Compared with baseline, AVP significantly increased MAP after 90 s (89+/-4 versus 160+/-5 mm Hg), increased LAD coronary artery cross sectional area (11.3+/-1 versus 11.8+/-1 mm(2)) and decreased cardiac index (138+/-6 versus 53+/-6 mL/min kg(-1)). After blockade of nitric oxide synthase, AVP significantly increased MAP after 90 s (135+/-4 versus 151+/-3 mm Hg), increased LAD coronary artery cross sectional area (8.7+/-1 versus 8.9+/-1 mm(2)), and significantly decreased cardiac index (95+/-6 versus 29+/-4 mL/min kg (-1)). IMPLICATIONS: During sinus rhythm, AVP increased MAP and LAD coronary artery cross sectional area, but decreased cardiac index.

Effects of vasopressin on left anterior descending coronary artery blood flow during extremely low cardiac output.

UNLABELLED: Because of the possibility of vasopressin-mediated coronary vasospasm, this study was designed to assess effects of vasopressin compared to saline placebo on left anterior descending (LAD) coronary artery blood flow. Twelve anaesthetized domestic swine were prepared for LAD coronary artery blood flow measurement with ultrasonic flow probes, using cardiopulmonary by-pass adjusted to 10% of the prearrest cardiac output. This 10% value approximates that reported for cardiac output during conventional closed-chest CPR. After 4 min of untreated ventricular fibrillation, and 3 min of cardiopulmonary by-pass blood flow, 12 pigs were randomly assigned to receive intravenously, every 5 min, either vasopressin (0.4, 0.4, and 0.8 U/kg; n = 6) or saline placebo (n = 6). The mean +/- S.D. LAD coronary artery blood flow in the vasopressin and placebo pigs was comparable before cardiac arrest, and during cardiopulmonary by-pass low flow; but increased significantly (P < 0.05) 90 s after each of three vasopressin injections compared to placebo (78 +/- 1 versus 42 +/- 2 ml/min; 62 +/- 2 versus 36 +/- 1 ml/min; and 54 +/- 1 versus 27 +/- 1 ml/min), respectively. Coronary vascular resistance decreased significantly (P < 0.05 ) 90 s after each of three vasopressin and placebo injections. In this model, repeated bolus administration of vasopressin, given during simulated extremely low cardiac output improved LAD coronary artery blood flow to prearrest levels without affecting coronary vascular resistance. CONCLUSIONS: during extremely low blood flow using cardiopulmonary by-pass, vasopressin improves LAD coronary artery blood flow without affecting coronary vascular resistance.

Two cycles of cisplatin-based chemotherapy for low-volume retroperitoneal stage II nonseminomatous germ cell tumours.

OBJECTIVE: To evaluate the oncological efficacy of reducing cisplatin-based chemotherapy to two cycles in patients with low-volume retroperitoneal stage II nonseminomatous germ cell tumours (NSGCTs). PATIENTS AND METHODS: From October 1988 until January 2004, two cycles of cisplatin-based chemotherapy were administered in 59 patients with low-volume retroperitoneal clinical stage II NSGCT (retroperitoneal mass of <5 cm in diameter). Regardless of remission detected on computed tomography, 6 weeks after chemotherapy the patients had a retroperitoneal lymph node dissection (RPLND) to assess residual active tumour or mature teratoma (open modified bilateral RPLND until 1992, then laparoscopic unilateral template RPLND). RESULTS: The chemotherapy was effective, as no active tumour was found in any of RPLND specimens. Mature teratoma was present in lymphatic tissue in 23 of 59 patients (39%). In one patient there was a pulmonary recurrence, successfully treated with cisplatin-based salvage chemotherapy. One patient died from an accident but with no evidence of tumour, and 56 patients remained free of disease at a mean follow-up of 98.6 months. No patient died from disease. All patients had antegrade ejaculation after laparoscopic RPLND, as did 89% after open RPLND. CONCLUSION: In this pilot study, the oncological efficacy of two cycles of cisplatin-based chemotherapy was favourable, but this approach still cannot be recommended as a standard treatment for patients with low-volume retroperitoneal stage II disease. RPLND after chemotherapy has diagnostic (detecting active tumour) and therapeutic (removing mature teratoma) value and can be done laparoscopically. Based on the present results a prospective randomized trial seems reasonable.

Management of incidental impalpable intratesticular masses of < or = 5 mm in diameter.

OBJECTIVE: To gain more insight into the histology of small incidental intratesticular lesions and evaluate the need for surgical management, as exploratory surgery is the only way to exclude malignancy in testicular tumours. PATIENTS AND METHODS: Between September 2000 and April 2005, incidental intratesticular masses of < or = 5 mm in diameter were found in 20 men undergoing scrotal ultrasonography for reasons other than suspected testicular tumour. After staging, an organ-sparing approach including frozen-section analysis was used to obtain histological data. RESULTS: The mean diameter of the detected tumour masses was 3.5 mm, and the mean (range) age of the patients was 36.4 (26-58) years. Four men (20%) had orchidectomy because the tumours were found to be malignant; the resected specimens yielded multifocal testicular intraepithelial neoplasia (TIN) in all patients and additional seminomatous tumour cells elsewhere in the testis in one. Frozen-section results were false-negative in one patient and he had orchidectomy after having established the definitive histological diagnosis. The 16 patients with benign lesions were correctly diagnosed and their testicles were not removed. CONCLUSIONS: Advanced and innovative ultrasonography technology allows the detection of increasingly small testicular masses. In the present series, most incidental intratesticular lesions were benign. In patients with malignant lesions, multifocal TIN and/or distant seminomatous foci were present despite the tumour being small. Therefore, it is essential to perform exploratory surgery as it is the only way to obtain accurate histological findings, thus providing oncological efficacy and precluding removal of a testicle bearing a benign lesion.

Tumor recurrence in the remnant urothelium of females undergoing radical cystectomy for transitional cell carcinoma of the bladder: long-term results from a single center.

PURPOSE: We analyzed the risk factors and incidence of secondary TCC of the remnant urothelium in women following radical cystectomy for TCC of the bladder. MATERIALS AND METHODS: A total of 85 women with a mean age of 64.5 years with clinically localized TCC of the bladder underwent radical cystectomy between 1992 and 2004. Orthotopic bladder substitution was performed in 46 females, while 39 underwent nonorthotopic urinary diversion. Of the entire cohort 22 (26%) patients underwent cystectomy for multifocal or recurrent TCC. Followup examinations were performed at 6-month intervals. RESULTS: Mean followup in the entire cohort was 49.8 months (median 42). Intraoperative frozen sections obtained from the urethra and distal ureters were negative for TCC and CIS in all patients. Four women (4.7%) had TCC in the remnant urothelium at a mean of 56 months postoperatively. These patients had undergone cystectomy for multifocal or recurrent TCC (4 of 22 or 18%). No secondary TCC was seen in the 63 patients with solitary invasive or nonrecurrent bladder cancer (p <0.05). Urethral recurrence was found in 2 patients (4.3%) 65 and 36 months after orthotopic neobladder surgery, respectively. In the orthotopic group 1 patient (2.1%) had an upper urinary tract tumor 76 months after surgery, while in the nonorthotopic group 1 (2.5%) was found to have an upper urinary tract tumor 48 months postoperatively. CONCLUSIONS: Recurrent or multifocal TCC may represent a risk factor for secondary TCC of the remnant urothelium after cystectomy. In our series all recurrent tumors were late recurrences (more than 36 months postoperatively). Because the rate of urethral recurrence in the current series corresponds to that reported in men (2% to 6%), urethra sparing cystectomy with orthotopic bladder replacement does not appear to compromise the oncological outcome in women.

A pilot study to evaluate the SMART BAG: a new pressure-responsive, gas-flow limiting bag-valve-mask device.

UNLABELLED: Reducing inspiratory flow rate and peak airway pressure may be important to minimize the risk of stomach inflation when ventilating an unprotected airway with positive pressure ventilation. In this study, we assessed the effects of a standard self-inflating bag compared with a new pressure-responsive, inspiratory gas flow-limiting device (SMART BAG) on respiratory mechanics in 60 adult patients undergoing routine induction of anesthesia. Respiratory variables were measured using a pulmonary monitor. The SMART BAG resulted in significantly decreased inspiratory flow rate and peak airway pressure while providing adequate tidal volume delivery. IMPLICATIONS: The SMART BAG, a new pressure-responsive, peak inspiratory gas flow-limiting bag-valve mask device, limits inspiratory gas flow from up to 120 L/min in a standard self-inflating bag to approximately 40 L/min. It is designed for use by all levels of health care professionals and has been proven in a clinical pilot study to effectively ventilate patients in respiratory arrest.