Ultrasound-Guided Renal Mass Biopsy and Its Clinical Utility: A Single-Centre Experience.

INTRODUCTION: Renal mass biopsy (RMB) is still underutilized, partially because many urologists argue that it does not substantially influence the management of renal masses. We sought to evaluate the influence of RMB on the management of renal tumours in our institution. MATERIALS AND METHODS: A total of 387 RMBs performed at our institution from January 2016 to June 2020 were included. Patient demographics, mass size, biopsy result, and subsequent clinical management were retrospectively reviewed. RESULTS: The mean mass size was 47.8 mm. Fifty-six percentage of tumours ≤40 mm (247) and 8% of tumours >40 mm (64) were biopsied. Seventy-six RMBs of disseminated tumours were performed. 14.9% of RMBs were non-diagnostic, and 27.1% of RMBs of tumours ≤40 mm were benign. The majority of tumours with first non-diagnostic RMB followed by histopathological verification were found to be malignant. There was significantly more conservative management and no radical nephrectomies in the benign biopsy group. One case of Clavien-Dindo grade ≥2 complication occurred. CONCLUSIONS: RMB result affects treatment decisions. Ultrasound-guided RMB is a safe procedure, and performing biopsies of tumours ≤40 mm may reduce the number of unnecessary interventions. Non-diagnostic RMBs should be repeated or treated as malignant.

Rho-kinase inhibitor reduces hypersensitivity to ANG II in human mesenteric arteries retrieved and conserved under the same conditions as transplanted organs.

Rho-kinase and GTP-ase Rho are important regulators of vascular tone and blood pressure. The aim of this study was to investigate the role of Rho-kinase in artery reactions induced by angiotensin II (ANG II) and the effects of ischemia-reperfusion injury as well as the function of intra- and extracellular calcium in these reactions. Experiments were performed on mesenteric superior arteries procured from cadaveric organ donors and conserved under the same conditions as transplanted kidneys. The vascular contraction in reaction to ANG II was measured in the presence of Rho-kinase inhibitor Y-27632, after ischemia and reperfusion, in Ca2+ and Ca2+-free solution. The maximal response to ANG II was reduced after ischemia, while an increase was observed after reperfusion. Vascular contraction induced by ANG II was decreased by Y-27632. Y-27632 reduced vascular contraction after reperfusion, both in Ca2+ and Ca2+-free solution. Reperfusion augments vascular contraction in reaction to ANG II. The Rho-kinase inhibitor Y-27632 reduces the hypersensitivity to ANG II after reperfusion mediated by both intra- and extracellular calcium. These results confirm the role of Rho-kinase in receptor-independent function of ANG II and in reperfusion-induced hypersensitivity.

Perioperative and Oncological Outcomes of Percutaneous Radiofrequency Ablation versus Partial Nephrectomy for cT1a Renal Cancers: A Retrospective Study on Groups with Similar Clinical Characteristics.

Over the recent years, progress in imaging techniques has led to an increased detection of kidney tumours, including small renal masses. While surgery is still the standard of care, there is a growing interest in minimally invasive methods. Ultrasound (US)-guided percutaneous ablation is particularly attractive because it is a safe and relatively simple procedure. In this study, we investigated the results of US-guided percutaneous radiofrequency ablation (RFA) and partial nephrectomy (PN) in the treatment of cT1a renal cancers. Between August 2016 and February 2022, 271 patients with renal tumours underwent percutaneous RFA as initial treatment in our institution. In the same period, 396 patients with renal tumours underwent surgical tumour excision. For the purpose of this study, only patients with confirmed renal cancer with matched age and tumour characteristics (size, location) were selected for both groups. Thus, a group of 44 PN patients and 41 RFA patients were formed with the same qualification criteria for both groups. Parameters such as procedure length, blood loss, hospital stay, analgesics used, and pre- and post-procedural serum creatinine were compared between these groups. Patients followed up with contrast-enhanced CT. There was no significant difference in age, tumour size, tumour location, and creatinine levels between these groups. All procedures were generally well tolerated. During a median follow-up of 28 months, two cases of recurrence/residual disease were found in each group. The overall survival was 100% in both groups, and all patients were disease-free at the end of observation. Percutaneous RFA was associated with a significantly shorter procedure length and hospital stay, lower blood loss, and lower analgesics used than PN. In the selected group of renal cancer patients, US-guided percutaneous RFA was associated with a shorter hospital stay, less analgesics used, and a shorter procedure length than PN, without differences in the oncological results or kidney function.

Serum Paraoxonase-1 Activity in Prostate Cancer Patients Treated with Brachytherapy as a Measure of Irradiation Efficacy.

We investigated changes in the activity of antioxidant paraoxonase-1 (PON1) in patients with prostate cancer (PCa) undergoing radiotherapy (RT), as well as the relationship of the PON1 activity with the degree of PCa advancement. We included 84 men with PCa. Blood samples were obtained before irradiation and after the completion of RT. The control group was composed of 60 healthy men. There was no significant difference in the PON1 activity between the control group and patients pre-radiotherapy. Irradiation was associated with a significant decrease in the PON1 activity; thus, it could be a measure of the efficacy of RT. No significant correlations between the PON1 activity and Gleason score, prostate volume, BMI (body mass index), or adipose tissue thickness were found. However, there was a positive correlation between the PON1 activity and the PSA concentration in the group of PCa patients.

Ultrasound-Guided Percutaneous Thermal Ablation of Renal Cancers-In Search for the Ideal Tumour.

Over the recent years, the progress in imaging techniques has led to an increased detection of kidney tumours, including small renal masses. While surgery is still the standard of care, there is a growing interest in minimally invasive methods. Ultrasound (US)-guided percutaneous ablation is particularly attractive because it is a safe and relatively simple procedure. In this study, we investigated the success of percutaneous radiofrequency ablation (RFA) in relation to kidney tumour diameter and location. Between August 2016 and September 2021, 253 patients with 259 renal tumours underwent US-guided RFA as a primary treatment in our institution. A total of 67 patients were excluded from this study. Abdominal computed tomography (CT) and tumour biopsy were performed before the procedure. Patients were followed with contrast-enhanced CT, the average follow-up time was 28 months. The studied group was composed of 186 patients with 191 renal tumours-only biopsy-confirmed renal cancers were included. During the follow-up, 46 cases of residual disease and 4 cases of local progression were found. There was a significant correlation between tumour size and the ablation success rate. The success rate was 73.5% and 87.6% for lesions ≤25 mm, 94.6% for lesions ≤25 mm and exophytic, 79.1% for lesions 26-30 mm and 84.4% for lesions 26-30 mm and exophytic, respectively. Four Clavien-Dindo grade ≥2 complications were observed. US-guided percutaneous RFA of T1a renal cancers is safe and well-tolerated. Its effectiveness depends on tumour size, with best results for exophytic lesions smaller than 3 cm. Most of the recurrent or residual tumours can be successfully re-treated with US-guided percutaneous RFA.

Can we rely on PET in the follow-up of advanced seminoma patients?

The management of residuals after completion of chemotherapy in advanced seminoma is controversial. It has been proposed that fluorodeoxyglucose-positron emission tomography (FDG-PET) can be used as a follow-up. In this study we investigated FDG-PET as a follow-up tool in advanced seminoma patients treated previously with chemotherapy or radiotherapy. Thirty-seven patients assigned to an advanced seminoma group based on CT and/or FDG-PET/CT and then treated with chemotherapy were included in the study. All these patients underwent FDG-PET/CT examination as a part of the follow-up scheme. Patients underwent retroperitoneal lymph node dissection (RPLND), radiotherapy, or were followed clinically by CT and/or PET/CT every 6 months. In 8 cases FDG-PET was positive: 5 of them underwent RPLND and 3 radiotherapy. Two patients with negative FDG-PET but positive CT also underwent RPLND. The remaining patients with negative FDG-PET results were followed up. FDG-PET/CT was false positive in one case >3 cm and one <3 cm, in 6 cases >3 cm it was true negative. While FDG-PET can find a viable tumor, there also is an important question of false positive results. It was clinically proven that a negative FDG-PET was correlated with stable disease, but we were unable to examine specimens in these cases.

Serum Paraoxonase-1 Activity and the Risk of Prostate Cancer Recurrence in Patients Treated with Radiotherapy.

The antioxidant paraoxonase-1 (PON1) may be involved in the response to radiation-induced oxidative stress and possibly prevent cell apoptosis. The correlation of PON1 with the risk of cancer recurrence after radiotherapy (RT) is not yet explored. We investigated changes in the activity of PON1 in patients with prostate cancer (PCa) undergoing RT, and the relation of PON1 activity to the risk of recurrence after RT. We included 56 men with PCa. Blood samples were obtained before irradiation and after the completion of RT. Patients were followed for an average of 51.2 months. Each case of biochemical recurrence was confirmed with biopsy. The control group was composed of 60 healthy men. There was no significant difference in PON1 activity between the control group and patients pre-radiotherapy. Irradiation was associated with a significant decrease in PON1 activity. Patients with PCa recurrence had significantly higher serum PON1 activity than those recurrence-free, both before and after RT. PON1 activity was a predictor of PCa recurrence, with sensitivity over 80% and specificity over 64%. Our results suggest that PON1 activity may be a predictor of PCa recurrence risk after RT. Studies with a larger number of patients and longer follow-up are needed to confirm this hypothesis.

Is botulinum toxin type a intraprostatic injections really effective in patients with urinary retention?

Botulinum toxin type A is used in treatment of bladder hyperactivity and sphincter dyssynergia and was reported to alleviate lower urinary tract symptoms in patients with BPH. Some authors, however, failed to observe in their study apoptosis after BoNTA administration. We conducted an open-label study of BoNTA in men with BPH-related LUTS who were unsuitable for surgery as well as investigation of the effect of the toxin on in vitro growth of fibroblasts. In the clinical part, 5 patients aged from 75 to 88, suffering from BPH and UR were treated. Patients were previously disqualified from surgery and had not passed trials without catheters (TWOC). Prostate volume ranged from 38 to 104 mL. Botulinum toxin injection were performed. Each lobe of adenoma was injected with 100 U Botox under sonographic guidance. Prostate volume and TWOC were performed after 6 months. In the in vitro part, 3T3 mouse fibroblasts and fibroblasts isolated from human prostate were cultured in the presence of Botox (10, 5 and 1 U/mL) for 24 and 72 h. Cells were detached and counted in Neubauer chamber using trypan blue assay. Cells cultured in medium without botulinum toxin were the control group. Results are presented as the means with standard deviations. The means were compared, p <0.05 was considered statistically significant.No early complications were observed. Prostate volume remained unchanged after six months and patients were unable to void. Number of 3T3 cells after 24 h incubation was 7.12 +/- 1.88, 7.12 +/- 0.64, 6.75 +/- 1.28 and 6.88 +/- 0.83 x 10(4), after 24 h, 24.00 +/- 3.46, 22.75 +/- 3.73, 23.12 +/- 3.46 and 23.88 +/- 2.42 x 10(4) after 72 h, for 0, 1, 5 and 10 U/mL botulinum toxin type A concentrations, respectively. Similarly, number of prostate fibroblasts was 7.50 +/- 1.20, 7.12 +/- 1.73, 6.50 +/-1.93, and 6.25 +/- 1.58 x 10(4) after 24 h and 9.62 +/- 2.00, 9.12 +/- 1.55, 9.12 +/- 1.73 and 9.75 +/- 2.82 x 10(4) after 72 h. In conclusion, Botox had no statistically significant, dose-dependent effect on neither 3T3 nor prostate fibroblasts proliferation. It caused no improvement in UR nor prostate volume reduction.

Long-term results of simultaneous and delayed liver resections of synchronous colorectal cancer liver metastases.

BACKGROUND: Complete resection is the only potential curative treatment of synchronous colorectal liver metastases. Although simultaneous liver and colon resections became an accepted procedure at specialized centres for selected patients, there is still little data about the long-term results of simultaneous operative procedures compared with those of delayed operations. In this retrospective study, the long-term survival rates of the patients who underwent simultaneous or delayed resections were presented. METHODS: A retrospective analysis of liver resections in our institution between 1997 and 2012 was performed. Among 131 patients presented with synchronous colorectal liver metastases, 52 underwent simultaneous and 79 delayed resection. Patients with extrahepatic metastases were excluded, except for 10 patients with metastases limited to liver and lungs that were qualified as resectable. RESULTS: Age, sex and localization of the primary tumour were similar in the two groups. In the delayed resection group, the majority of colon resections were performed in different hospitals. The frequency of complications did not differ between the groups. The 1, 5 and 10 years survival rates were 77%, 43% and 20% in simultaneous and 86%, 37% and 19% in delayed resection group, respectively. No cancer related deaths occurred after more than 10 years of observation. CONCLUSION: The long-term outcome of simultaneous resection of synchronous colorectal liver metastases is comparable to delayed resection.

Outcomes of simultaneous and delayed resections of synchronous colorectal liver metastases.

BACKGROUND: The optimal strategy for the treatment of synchronous colorectal liver metastases has not been established yet. In this study, we present the outcomes and survival rates of the patients who underwent simultaneous or delayed resections. METHODS: We performed a retrospective analysis of liver resections in our institution between 1997 and 2006. RESULTS: Among the 89 patients presenting with synchronous colorectal liver metastases, 28 underwent simultaneous and 61 underwent delayed resection. Age, sex and localization of the primary tumour were similar in the 2 groups. Duration of surgery and hospital stay were longer in the simultaneous resection group, and blood loss was also greater in this group. However, these factors did not influence the frequency of complications, which did not differ between the groups. When we included data from initial colectomy, these differences were either not significant or in favour of synchronous resection. In the delayed resection group, colon resection was performed in different hospitals. The 1-, 3- and 5-year survival rates were 78%, 70% and 45%, respectively, in the simultaneous and 88%, 55% and 38%, respectively, in the delayed resection groups. CONCLUSION: In select patients, the risk of simultaneous resection of synchronous colorectal liver metastases is comparable to delayed resection, and increases in blood loss and operating time associated with simultaneous resections do not have a negative influence on long-term outcome. Positive outcomes of simultaneous liver resections in our study could be a result of good patient selection or experience with oncological liver surgery.

Comparison of 3T3 fibroblasts growth on alginate and polyasparagine (PAA) scaffolds in mouse model.

INTRODUCTION: The aim of this study was to evaluate polyasparagine (PAA), a new, promising scaffold. PAA was compared with alginate, which is used in cell transplantations and may be regarded as a standard. MATERIALS AND METHODS: In vitro cell viability on both scaffolds was assessed. C57B1 mice were injected s. c. alginate or PAA with or without 3T3 cells. After two months specimens from sites of injection were examined and blood samples were taken for enzymatic activity estimation. Cathepsin D activity and alpha1-antitrypsin levels were measured. RESULTS: In vitro cell viability was lowest on PAA and highest in control group. Increase in levels of enzymes measured was observed in response to PAA and alginate and was lower in case of polymer seeded with cells. Increase in alpha1-antitrypsin levels was lower in case of PAA in comparison to alginate. Scaffold degradation in histopathological specimens was visible. CONCLUSION: The results indicate that PAA implants undergo biodegradation and nonspecific inflammatory response is comparable to alginate.

Radiofrequency ablation of small renal masses in comorbid patients.

INTRODUCTION: Over the recent years, the progress in imaging techniques has led to increased detection of small renal masses (SRMs), including in elderly and high-risk patients. Partial nephrectomy (nephron-sparing surgery - NSS), the current standard of care in T1a kidney tumours, has some limitations in patients who are poor candidates for surgery, as it is associated with potential perioperative complications and possible renal function loss. Radiofrequency ablation (RFA), a minimally invasive method that can be performed percutaneously, is an option in such cases. AIM: To present our experience in treatment of SRMs using RFA in comorbid patients. MATERIAL AND METHODS: In the years 2006-2012, 103 percutaneous, ultrasound-guided RFA procedures were performed in the Oncology Centre in Bydgoszcz in patients with an ASA score ≥ 3. Abdominal computed tomography and tumour biopsy were performed before the procedure. The average follow-up time was 46 months. RESULTS: The 1, 3 and 5-year overall survival rates were respectively 97%, 90% and 75%, while cancer-specific survival was 100%. No Clavien-Dindo grade ≥ 3 complications were observed. CONCLUSIONS: Radiofrequency ablation performed percutaneously is a minimally invasive treatment and may be applied in patients who are, due to comorbidities, poor candidates for surgery. In comorbid patients, where other causes of death play an important role, the application of a minimally invasive treatment method with satisfactory oncological effectiveness is justified.

Inosine monophosphate dehydrogenase 2 as a marker of aggressive and advanced prostate cancer.

INTRODUCTION: There is a need for a new biochemical marker of aggressive prostate cancer (PCa). Inosine monophosphate dehydrogenase 2 (IMPDH2) is a candidate for such a marker - its activity is increased in certain tumors and neoplastic cell lines, including PCa, and may correlate with cancer aggressiveness. MATERIAL AND METHODS: IMPDH2 levels were measured in blood samples from 34 PCa patients. The results were analyzed and correlated with prostate-specific antigen (PSA), digital rectal examination (DRE), Gleason score, risk groups according to d'Amico and metastatic disease. Twenty healthy (non-PCa) patients served as the control group. RESULTS: There was no significant difference in IMPDH2 level between the PCa and control group, and no significant correlation between PSA and IMPDH2. IMPDH2 levels were significantly higher in the DRE (+) patients (148.5 ±174.8 vs. 33.4 ±46.4, p <0.05), in patients with metastatic disease (100.1 ±139.0 vs. 25.3 ±25.9, p <0.05) and in the high-risk group according to d'Amico (93.4 ±129.2 vs. 18.8 ±10.4, p <0.05). There was a significant correlation between the Gleason score and IMPDH2. CONCLUSIONS: These results suggest that IMPDH2 is a promising candidate as a biomarker for those with advanced PCa and those at high risk of progression towards advanced PCa.

Unexpected response to systemic chemotherapy in case of primarily nonresectable advanced disseminated intrahepatic cholangiocarcinoma.

BACKGROUND: Cholangiocellular cancers account for about 10-15% of primary liver cancers. Prognosis is poor, with expected survival of less than 5% at five-year. CASE PRESENTATION: The case described shows remission of a disseminated cholangiocellular carcinoma (focal changes in liver, metastases to lungs) after neoadjuvant chemotherapy. The initial diagnosis was based on ultrasound examination and confirmed with computer tomography. Tumour biopsy and histopathological examination revealed cholangiocellular carcinoma. The patient underwent chemotherapy. After remission of lesions in lungs and reduction/regression of tumours in liver to one focal change, right lobe liver resection was performed. The histopathological examination did not reveal any viable carcinoma cells, only necrotic tissues in place of the primary tumour as well as in local portal vein branches was seen. Thirty months after the operation the patient is in a good overall condition and no recurrence has been observed. CONCLUSION: Appropriate neoadjuvant chemotherapy may allow radical resection in a previously unresectable cholangiocellular cancer.

Resveratrol in prostate diseases - a short review.

INTRODUCTION: Resveratrol is a plant-derived polyphenol suggested to have many beneficial health effects, including antioxidant, anti-inflammatory, anti-proliferative, proapoptotic, and anti-angiogenic. It is even specu- lated that uptake of resveratrol by red wine consumption could be behind the so-called French paradox the lower incidence of cardiovascular diseases in the French population. These properties, together with good absorption and tolerance, would make it an attractive agent in prostatic diseases, especially in cancer prevention and treatment. MATERIAL AND METHODS: MEDLINE search (keywords "prostate res- veratrol") resulted in 39 research papers published since 2007. It has been shown that resveratol down-regulate androgen receptor expression, inhibit proliferation, and promote apop- tosis in prostate cancer cell lines and enhance their sensitivity to ionizing radiation. Several studies on animal prostate cancer development also suggest that resveratrol is able do delay or prevent carcino- genesis in prostate. Despite these promising results, there is no proof of any therapeutic properties of resveratrol in prostate diseases from human clinical trials nor any information about ongoing trials in this field. CONCLUSIONS: Resveratrol is produced and sold as a nutritional supplement, there is not enough clinical evidence to justify a recommendation for the administration of resveratrol in humans at present.

A brain dead woman, giving birth in the 23rd week of pregnancy, used as an organ donor: a case report.

BACKGROUND: Maternal brain death during pregnancy is an exceptional case when somatic support might be continued despite diagnosed death. There are only a few cases of maternal brain death during pregnancy reported in the literature and detailed data regarding the frequency of such cases are lacking. CASE REPORT: The case of a 40-year-old woman, diagnosed brain dead due to a subarachnoid and intracranial hemorrhage in the 21st week of pregnancy is presented. The patient was admitted to the neurosurgery department and then to the intensive care unit, where brain death was diagnosed. The medical team decided to perform a caesarean section, and a living female infant was delivered. After delivery, maternal kidneys were recovered and successfully transplanted. CONCLUSIONS: This challenging case indicates that prompt diagnosis of maternal brain death is required to facilitate decision-making regarding somatic support prolongation to save the life of the fetus, as well as to allow procurement of the maternal organs.

Radiofrequency ablation of small renal masses as an alternative to nephron-sparing surgery: preliminary results.

INTRODUCTION: Radical endoscopic minimal-invasive treatment methods, such as thermal ablation, are sought as an alternative to standard radical surgical treatment of kidney neoplasms. We analysed patients who could be qualified for radical treatment due to T1a renal tumour. MATERIAL AND METHODS: Twenty-three patients out of 129 who underwent radiofrequency thermal ablation of kidney tumours in the years 2003-2010 were analysed. The inclusion criteria were age below 70 years, lack of major comorbidities (ASA score 1, 2), and competent contralateral kidney. In all cases tumour size was below 4 cm. All patients were followed up with computed tomography (CT) and ultrasonography (USG) every 6 months for 3 years. RESULTS: In 20 patients kidney tumour was biopsied before radiofrequency ablation (RFA) and 10 of these biopsies were positive and revealed cancer. Six patients required additional treatment due to recurrence visible in CT - 3 with a positive biopsy result, 1 with negative and 2 without biopsy. Three of them were treated with a second session of RFA, 1 with radical nephrectomy and 2 with partial nephrectomy. No disease dissemination was observed and all patients who received additional treatment remain disease free. CONCLUSIONS: The RFA can be safely used in selected patients with T1a tumour as an alternative to partial nephrectomy. Careful follow-up is required after thermal ablation and allows early detection and successful treatment of recurrences.

Lymph node dissection during laparoscopic (LRC) and open (ORC) radical cystectomy due to muscle invasive bladder urothelial cancer (pT2-3, TCC).

AIM: The aim of the study was to compare the number of nodes dissected during laparoscopic and open radical cystoprostatectomy in men or anterior exenteration in women due to muscle invasive bladder urothelial cancer (IBC). MATERIAL AND METHODS: Fifty-one patients treated with laparoscopic radical cystectomy (LRC) and 63 with open radical cystectomy (ORC) were compared. The LRC group consisted of 47 pT2 tumours and 4 pT3, while the ORC group was composed of 27 pT2 tumours and 36 pT3. During ORC external, internal, common iliac and obturator lymph nodes were removed separately, but were added and analysed together for each side. Nodes dissected from one side during ORC were compared to en bloc dissected nodes in the LRC group. RESULTS: There were no complications associated with extended pelvic lymph node dissection during LRC or ORC. There were significant differences in the mean number of resected lymph nodes between LRC and ORC for pT2 tumours. The laparoscopic approach allowed about 8-9 more lymph nodes to be removed than open surgery in the pT2 group. In 15% of patients with pT2 disease treated with open radical cystectomy node metastases were observed. Active disease was detected in 18% of nodes resected laparoscopically due to pT2 disease. Fourty-seven percentage of patients with pT3 disease treated with open surgery were diagnosed as harbouring metastatic lymph nodes. The laparoscopic group with pT3 disease was too small to analyse. CONCLUSIONS: We have found that laparoscopic radical cystectomy can be performed without any compromise in lymph node dissection. The technique of lymph node dissection (LND) during laparoscopic cystectomy (LRC) resulted in sufficient resected lymphatic tissue, especially in patients with bladder-confined tumours with a low volume of lymph nodes.

The role of the endothelium in the regulation of vascular smooth muscle cell contractions induced by angiotensin II after ischemia and reperfusion.

In this study, we investigated smooth muscle cell contractions induced by angiotensin II (ANG II) in blood vessels with or without endothelium after ischemia/reperfusion. Experiments were done on tail arteries, with or without endothelium, of perfused male Wistar rats. We analyzed the influence of ANG II on vascular contractions in the presence of sodium nitroprusside or 8Br-cGMP and after ischemia/reperfusion using classical pharmacometric methods. Vascular contractions induced by ANG II were decreased by sodium nitroprusside and 8BrcGMP. Reductions in maximal response and increases in EC(50) values after ischemia were observed only in vessels with endothelium. After reperfusion, increases in maximal response and decreases in EC(50) values were observed. Decreases in ANG II induced vascular contractions on caused by ischemia involves the presence of endothelium, synthesis of nitric oxide and activation of cGMP. The increase in the reaction to ANG II that is induced by reperfusion is independent of the endothelium.