Hybrid procedures as a combined endovascular and open approach for pararenal and thoracoabdominal aortic pathologies

OBJECTIVES: to report our experience with hybrid vascular procedures in patients with pararenal and thoracoabdominal aortic pathologies. METHODS: 68 patients were treated for thoracoabdominal aortic pathologies between October 1999 and February 2004; 19 patients (16 men; mean age 68, range 40-79) with high risk for open thoracoabdominal repair were considered to be candidates for combined endovascular and open repair. Aortic pathologies included five thoracoabdominal Crawford I aneurysms, one postdissection expanding aneurysm, three symptomatic plaque ruptures (Crawford IV), five combined thoracic descending and infrarenal aneurysms with a healthy visceral segment, three juxtarenal or para-anastomotic aneurysms, and two patients with simultaneous open aortic arch replacement and a rendezvous maneuver for thoracic endografting. Commercially available endografts were implanted with standardized endovascular techniques after revascularization of visceral and renal arteries. RESULTS: Technical success was 95%. One patient developed a proximal type I endoleak after chronic expanding type B dissection and currently is waiting conversion. Nine patients underwent elective, five emergency and five urgent (within 24 h) repair. 17 operations were performed simultaneously, and 2 as a staged procedure. Postoperative complications include two retroperitoneal hemorrhages, and one patient required long-term ventilation with preexisting subglottic tracheal stenosis. Thirty-day mortality was 17% (one multiple organ failure, one secondary rupture after open aortic arch repair, one myocardial infarction). Paraplegia or acute renal failure were not observed. Total survival rate was to 83% with a mean follow-up of 30 months. CONCLUSIONS: Midterm results of combined endovascular and open procedures in the thoracoabdominal aorta are encouraging in selected high risk patients. Staged interventions may reduce morbidity.     

Medical Research Council leukaemia trial--UKALL V: an attempt to reduce the immunosuppressive effects of therapy in childhood acute lymphoblastic leukemia. Report to the Council by the Working Party on Leukaemia in Childhood

The Medical Research Council UKALL V trial for children with standard-risk acute lymphoblastic leukemia (ALL) (aged 1 to 14 years, leucocyte count less than 20 X 10(9)/L) was designed to determine whether the immunosuppressive effects of treatment could be reduced without sacrifice of antileukemic effect by alterations in the type of continuing therapy or in fractionation of cranial irradiation. Remission was achieved in 496 children on standard induction therapy, and 309 children received 24 Gy of cranial irradiation in ten to 16 fractions over 21 days, and 174 received 21 Gy in five to nine fractions over 21 days. The type of radiotherapy administered had no influence on relapse at any site or rate of death in remission. All 496 children were randomized to receive chemotherapy for 2 or 3 years with 6-mercaptopurine and methotrexate either as a continuous (group C) or a semicontinuous (group G) regimen or as a five-day pulse every 3 weeks (group I). All groups also received vincristine and prednisolone every 6 weeks. With a minimum follow-up of almost 7 years, patients in group I had significantly fewer remission deaths (P = .025) but a much higher rate of bone marrow relapse than those in group C or G (P = .002). There was an overall benefit for 3 years of chemotherapy compared with 2 years, which in contrast to previous studies, was more apparent in girls and in patients in groups C and G. Testicular relapse occurred in 37 boys, including 19 patients off therapy, with a previously negative biopsy. The overall results confirmed the prognostic significance of initial leucocyte count, even among these standard-risk patients, while girls had a superior rate of disease-free survival, but not of hematologic remission. It is concluded that, even among standard-risk patients, the prognosis is influenced by the height of the initial leukocyte count. While alterations in the fractionation of cranial irradiation do not appear to have influenced disease-free survival, intermittent continuing chemotherapy, although less immunosuppressive, is less effective than conventional continuous therapy in the treatment of ALL. In this study, 3 years of chemotherapy appeared superior to 2 years.     

Immunomodulation of vascular endothelium. 1. Ultrastructural changes following ultraviolet B irradiation of peripheral veins

Immunologic function of endothelial cells is especially important in consideration of vein allografting for arterial reconstruction and in organ allotransplantation. Ultraviolet B radiation (UVB) has previously been shown to modulate graft immunogenicity, and to alter cell surface receptor function. In this study, superficial epigastric veins were UVB irradiated with 10, 24, 40, 80, and 150 mJ/cm2 while control veins were not irradiated; all specimens were examined for endothelial ultrastructural changes. Veins were perfuse-fixed at 1, 3, 7, 14, and 28 days after irradiation, and were evaluated by transmission electron microscopy and scanning electron microscopy. Control veins had a normal appearing endothelial lining, composed of elongated, attenuated endothelial cells. Veins irradiated with more than 24 mJ/cm2 displayed injured endothelial cells characterized by altered microvilli, defects in the cell surface, and a change in cell shape. The degree of cell damage correlated closely with increasing UVB dose. At doses of 80 mJ/cm2 or greater there was moderate to severe endothelial cell separation from the underlying basement membrane and an increase in cellular lysosomes. The effects of UVB were maximal at 3 days with virtual recovery in resurfacing of all specimens with endothelium 28 days after irradiation. These data suggest that UVB has a dose-dependent effect on venous endothelium that is morphologically reversible with time. Cell membrane changes seen following exposure to UVB may contribute to altered cell surface receptor function.     

Pyloromyotomy of Ramstedt: experience of a nonspecialized centre

In a general hospital over a period of 6 years 57 infants with congenital hypertrophic stenosis underwent a Ramstedt pylorotomy. In most cases a surgical resident-in-training performed the operation under the direct supervision of a general surgeon. There were no complications of anesthesia, no deaths and no substantial morbidity. The majority of infants left the hospital within 48 hours. The results in this series compared favourably with those reported from more specialized centres.     

VASOCONSTRICTOR RESPONSES TO COMPONENTS OF THE RENIN-ANGIOTENSIN SYSTEM IN CYCLOSPORIN-INDUCED HYPERTENSION IN THE RAT

1. Since plasma renin activity is increased in cyclosporin A (CsA)-induced hypertension in the rat, the role of the vascular renin-angiotensin system (RAS) in CsA-induced hypertension was investigated in rat mesenteric resistance vessels. 2. Female Wistar rats received CsA (10 mg/kg per day, s.c.) or vehicle for 30 days. CsA treatment increased tail-cuff systolic blood pressure (CsA treated 135 ± 3 mmHg vs control 125 ± 1 mmHg, P<0.0001). 3. Mesenteric resistance arteries (200–300 μm) were isolated and mounted in a microvessel myograph. Concentration-response curves to tetradecapeptide renin substrate (10-¹¹-10^?6 mol/L), angiotensin I (10-^l1-10^?6 mol/L) and angiotensin II (10-¹²-10^?6 mol/L) showed no differences between CsA-treated and control groups. 4. Mesenteric vascular angiotensin-converting enzyme (ACE) characteristics were determined by radioligand binding. There were no differences in the content or affinity of ACE between CsA-treated and control rats. 5. These results suggest that the mesenteric vascular RAS does not play a major role in CsA-induced hypertension in the rat.     

A juvenile animal model to study the growth potential of bowel segments in the urinary tract

A juvenile animal model has been developed to study the growth potential of ileum in the urinary tract. Patch ileocystoplasties of known surface area were constructed in dogs of Group 1. Nonrefluxing ileal nipple valves of known length were created to replace one ureter in dogs of Group 2. After the juvenile animals grew and at minimum doubled their weight, they were reoperated and augmentation surface areas were remeasured at various physiologic intravesical pressures. Nipple valve lengths were remeasured after cystograms ruled out reflux. Results show that the bowel augmentation and an identical control segment increased in surface area proportionate to animal growth and that hydrostatic dilation caused further surface area increase. Nipple valves did not grow and in fact shortened, but remained nonrefluxing. The conclusion is that in the pediatric population, consideration should be given to downscaling the size of bladder augmentations or diversions in anticipation of future bowel growth, but that one should not shorten the ileal nipple valves.     

Rapid 31P spectroscopy on a 4-T whole-body system

Initial 31P spectroscopy results from a 4-T whole-body system are reported. Localized spectra from the human head, liver, and calf were obtained using DRESS, slice-interleaved DRESS, and volume 3DFT spectroscopic imaging techniques. Substantial reductions in data acquisition times to 10 s-4 min were achieved relative to previous similar experiments at 1.5 T. Some gain in spectral resolution (as measured in ppm) was also realized in the head.     

Histamine-operated calcium channels in intestinal smooth muscle of the guinea-pig

The effects of Bay K 8644 and of nifedipine on histamine-induced mechanical and electrical responses were studied in the longitudinal smooth muscle of the ileum and in the taenia coli isolated from the guinea-pig. Nifedipine (10(-9)-10(-7) M) depressed the tonic and phasic components of histamine contraction. Phasic tension was less sensitive to nifedipine inhibition than was tonic tension (I50: 27 +/- 6 and 2.6 +/- 0.4 nM respectively). Bay K 8644 (10(-8)-10(-7) M) increased tension and rhythmic activity of intestinal smooth muscle and potentiated the histamine responses. The phasic tension evoked by histamine 10(-5) M and the phasic tension evoked by the KCl depolarizing solution showed the same sensitivity to nifedipine inhibition (I50: 28 +/- 5 nM) and were similarly potentiated by Bay K 8644. The tonic tension in response to the KCl-depolarizing solution was more sensitive to nifedipine inhibition than was the tonic tension in response to histamine and was not potentiated by Bay K 8644. These results indicate that different Ca entry pathways, dependent or not on modification of the membrane potential, are involved in the contractile response evoked by histamine in intestinal smooth muscle.