Dynamics of lysozyme and its hydration water under an electric field.

The effects of a static electric field on the dynamics of lysozyme and its hydration water are investigated by means of incoherent quasi-elastic neutron scattering (QENS). Measurements were performed on lysozyme samples, hydrated respectively with heavy water (D2O) to capture the protein dynamics and with light water (H2O), to probe the dynamics of the hydration shell, in the temperature range from 210 < T < 260 K. The hydration fraction in both cases was about ∼ 0.38 gram of water per gram of dry protein. The field strengths investigated were respectively 0 kV/mm and 2 kV/mm (~2 × 10(6) V/m) for the protein hydrated with D2O and 0 kV and 1 kV/mm for the H2O-hydrated counterpart. While the overall internal protons dynamics of the protein appears to be unaffected by the application of an electric field up to 2 kV/mm, likely due to the stronger intra-molecular interactions, there is also no appreciable quantitative enhancement of the diffusive dynamics of the hydration water, as would be anticipated based on our recent observations in water confined in silica pores under field values of 2.5 kV/mm. This may be due to the difference in surface interactions between water and the two adsorption hosts (silica and protein), or to the existence of a critical threshold field value Ec ~2-3 kV/mm for increased molecular diffusion, for which electrical breakdown is a limitation for our sample.

[A new conservative approach in the treatment of postoperative digestive-tract fistulas. Mechanical closure by a balloon-catheter]. / Nuova metodica conservativa nel trattamento delle fistole digestive postoperatorie. Chiusura meccanica con catetere con palloncino.

BACKGROUND: Digestive fistulas represent troublesome complication in patients operated in modern surgical wards where the improved surgical procedures and better intensive care enhance the surgeon to perform more aggressive approaches with a high surgical risk index. The management of a patient presenting a digestive-tract fistula is never easy, being its approach either conservative (TPN) or surgical. We applied an alternative surgical procedure consisting in a mechanical closure of the fistula using a balloon-catheter so as to improve outcome in those patients in whom medical tratment did not show satisfactory RESULTS. METHODS: We treated 7 patients presenting a postoperative fistula following several surgical procedures for neoplasms of the digestive system. These fistulas were closed using a Foley or Fogarthy balloon catheter preceeded by radiological and/or endoscopy controls. Once the catheter was placed, oral nutrition was started and some patients were discharged. A progressive deflation of the balloon was performed until complete removal of the catheter upon approx 10 days. RESULTS: We obtained a complete healing of the fistula in 6 patients, within 10 days since catheter placement. Only one patient required another operation. CONCLUSIONS: Our case-series may seem statistically not significant, but varied concerning location and type of fistulas. We observed an excellent outcome using this procedure which allows very short healing period thanks to an early oral nutrition uptake and a decrease in costs mainly due to a short hospital stay and a minor use of expensive drugs (TPN).

Simultaneous total aortic replacement from valve to bifurcation: experience with 21 cases.

From June 1985 to December 1991, 21 patients (12 men and 9 women; mean age, 60 years) underwent total simultaneous aortic replacement that extended from the valve to the bifurcation. The causes of the diseased aorta were: medial degeneration with total aortic dilatation or multiple aneurysms (n = 7) and either acute (n = 4) or chronic (n = 10) dissection. Clinical evaluation and investigation in all patients consisted of computed tomography and magnetic resonance imaging as well as angiography. Only patients with combined thoracic and abdominal emergencies were selected, and these comprised worsening of cardiac conditions resulting from aortic regurgitation, and rapid dilatation of the ascending aorta and arch with impending rupture in conjunction with ischemia of the abdominal viscera, kidney, or either leg. The surgical technique consisted of inducing deep hypothermia by means of femoral vein-femoral artery cardiopulmonary bypass. During the cooling time, the aortic root was replaced under cardioplegia. Once lowering of the body temperature attained electroencephalographic silence, circulation was stopped and the aorta was replaced from the arch to the bifurcation. Circulation and rewarming were resumed only after the operation was completed. In our most recent patient, the operating time was reduced by opening the thoracic and the abdominal incisions during cooling; the cardioplegic solution as not injected but, instead, the myocardium was cooled down along with the whole body. In these patients, the hypothermy at electroencephalographic silence ranged from 14 degrees to 19 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

[Extensive lymphadenectomy in the therapy of cancer of the left colon and rectum: an analysis of the anatomicopathological data]. / La linfectomia allargata nella terapia del cancro del colon sinistro e del retto: analisi dei dati anatomo-patologici.

In the last 12 years in our surgical service, radical resection was performed in 142 patients with cancer of left colon and in 145 patients with rectal cancer. Extended lymphadenectomy was always realized: preaortocaval lymphadenectomy in colonic cancer; preartocaval and pelvic lymphadenectomy in rectal cancer. The incidence of C stage was 40.14% in cancer of left colon and 40.68% in rectal cancer. Neoplastic diffusion in preaortocaval lymph nodes was only in a patient with colonic cancer, never in patients with rectal cancer. The incidence of neoplastic diffusion in pelvic nodes was 3.12% (0 in superior rectum; 6.25% in medium rectum; 2.4% in inferior rectum). In 1 of 90 patients with tumour of medium or inferior rectum, we relieved tumoural involvement of pelvic nodes without neoplastic diffusion in regional nodes. These anatomo-pathological data subline: a) the low incidence of neoplastic diffusion in preaortocaval nodes in cancer of left colon and rectum; b) the importance of pelvic lymphadenectomy in cancer of medium and inferior rectum.

[Appendicitis: microbial interactions and new pathogens]. / Appendicite: interazioni microbiche e nuovi patogeni.

The Authors present an exhaustive review on microbial agents of appendicitis by means of literature and personal research data. Thus, a detailed analysis is made on common autochthonous agents and their pathogenetic interactions and on less common exogenous bacterial, viral, mycotic, protozoan and helminthic agents with emphasis to the role of Yersinia enterocolitica. In fact this bacterium seems responsible for 3% to 8% of cases in accordance with literature and personal research data (more detailed, Y. enterocolitica has been isolated in 3.8% of 208 inflamed appendices from both pediatric and adults surgical florentine patients). At the end, the pathogenetic role of "new" other bacteria, like Buttiauxella agrestis, Aeromonas hydrophila, Arizona, Streptococcus lactis, is debated on the basis of a personal study.

[Intrathoracic revascularization of the stomach in gastroplastic reconstruction of the esophagus]. / La revascularisation intrathoracique de l'estomac dans les reconstructions gastroplastiques de l'oesophage.

Reconstruction of the thoracic esophagus after esophagectomy is usually achieved using the stomach which, after gastrolysis through an abdominal approach, is pulled into the right thoracic cavity and anastomosed to the esophagus. After gastrolysis by conventional methods, the blood supply of the stomach exclusively depends on the right gastric and epiploic arteries. In some cases, these arteries cannot ensure sufficient blood supply to the fundus of the stomach, which is at higher risks from a vascular point of view, since it depends on the intraparietal capillary anastomoses between the gastric branches on the left inferior gastric artery, the intraparietal rami of the short gastric arteries, which have been cut, and the parietal rami of the anterior cardiotuberous artery. When macroscopic signs of ischemic disorders of this area are observed intraoperatively, resection of the fundus of the stomach would considerably reduce the length of the organ that could be used for gastric esophagoplasty. To avoid this, we have been implementing an intrathoracic revascularization technique consisting in anastomosing the left gastric artery, either directly with the right internal mammary artery, or through a shunt with the saphenous vein between the subclavian artery and the left gastric artery itself. Finally, the intensification of the venous circle is performed by anastomosing the left gastric vein and the azygos vein. Details of the surgical technique, as well as the results obtained, are illustrated.

Excision of the aortic wall in the surgical treatment of acute type-A aortic dissection.

Between March 1986 and September 1988, 38 patients underwent extended aortic resection (aortic valve, ascending aorta, and arch) for acute type-A aortic dissection with aortic valve insufficiency; deep hypothermia and circulatory arrest were used. All patients were operated on within 17 hours of the onset of symptoms. In the first 24 patients, operation was performed by the "inclusion technique." In the last 14 patients, the "excision technique" was used: the ascending aorta and arch was excised, and the aorta was transected at the beginning of the descending thoracic tract. Excision and transection were considered essential to prevent back flow from the false lumen, which is the main source of bleeding, and to allow all anastomoses to be constructed beyond the limits of dissection. The only anastomosis to the dissected aorta was at the distal end of the graft. One of the 14 patients died (7.1%). One patient was reopened for bleeding: blood was issuing from the attachment of the carotid trunks, and the defect was repaired by interposing a bifurcated Dacron graft between the arch graft and the carotid arteries. Extended aortic excision meets the principle of either eliminating as far as possible the diseased aorta or controlling intraoperative and postoperative bleeding. An operation of great magnitude can be considered a life-saving procedure when compared with the high risk of acute type-A aortic dissection.

Extended and total aortic resection in the surgical treatment of acute type A aortic dissection: experience with 54 patients.

Fifty-four patients with acute type A aortic dissection were surgically treated with extended aortic resection. The age of the patients ranged from 22 to 75 years, and all of them were in very critical condition. In 50 patients, the resection extended from the aortic valve (included in 33) to the beginning of the descending thoracic aorta and in 4, from the valve (included in 3) to the aortic bifurcation. Deep hypothermia and circulatory arrest were employed during the aortic arch resection; inclusion of the graft at the end of procedure was done in 44 patients; in the others, the diseased aortic wall was excised. Early mortality was 20 +/- 6% (11/54). Nine deaths were due to persistence of the distal dissection. Acute type A aortic dissection with aortic valve insufficiency should be treated as an emergency with extended aortic resection. As far as control of bleeding and closure of distal dissection are concerned, the best results have been achieved when the diseased aortic wall has been completely excised.

Coronary reconnection in emergency "conduit operation" for acute type-a aortic dissection with aortic insufficiency: experience with 24 cases.

Twenty-four cases of acute type-A aortic dissection with aortic valvular insufficiency were treated in our institution by means of an emergency operation in which the aortic valve, ascending aorta, and aortic arch were resected and replaced with a valved conduit that had been lengthened with a tubular Dacron graft. The procedure included the use of deep hypothermia for cerebral protection, as well as extracorporeal circulation. Aortic resection was performed from the aortic valve to the origin of the descending thoracic aorta; the aortic graft was anastomosed proximally to the valve annulus and distally to the descending aorta. The carotid orifices were connected to the side of the graft in a single tissue button. The coronary arteries were then reconnected by means of double venous bypass grafts to the innominate artery, to allow for inclusion of the graft. Within 1 month after operation, four patients died of the consequences of dissection. Six months postoperatively, one patient succumbed to an infarction. Six months to 5 years after operation, the remaining 19 patients are still alive. On the basis of this experience, we believe that acute type-A aortic dissection with aortic valvular insufficiency should be treated during the first hours after the onset of symptoms. The above-described procedure proved effective in the control of bleeding, which is the major risk in emergency operations of this type.

Simultaneous total aortic replacement from arch to bifurcation: experience with six cases.

Simultaneous total aortic replacement, including the arch and extending to bifurcation, has been performed in six cases at our institution. The cases presented were (1) acute dissection, including the intimal tear in the arch (one case); (2) chronic Type-I dissection, with both visceral and inferior limb ischemia (three cases); and (3) multiple aneurysms (two cases). The broad outline of the surgical technique employed consists of inducing general hypothermia with extracorporeal circulation. At core temperature of 20 degrees C, circulation is stopped and the aortic arch is replaced. Afterward, cerebral perfusion and total body perfusion are resumed at low flow, keeping body temperature between 20 and 24 degrees C. The intercostal orifices are attached to the side of the aortic graft, and the spinal cord is reperfused. Finally, during a period of hypothermic abdominal ischemia, the abdominal aorta is replaced, and subsequently, rewarming is started. This result is achieved by instituting extracorporeal circulation with two arterial return cannulae (in the ascending aorta and in a femoral artery), making it possible to continue the perfusion of both the upper and lower body during the stages of aortic occlusion. Two patients died from bleeding 3 to 6 hours after operation, and medullary injury was not ascertained; one patient died after 1 month without neurologic disturbances; three patients are alive and in good functional condition 6 to 27 months after operation. We believe that total simultaneous aortic replacement is feasible with the hypothermic technique.

[Emergency gastro-duodeno-cephalo-pancreatectomy for gastroduodenal necrosis caused by ingestion of caustics]. / Gastro-duodeno-cefalo-pancreasectomia d'urgenza per necrosi gastro-duodenale da ingestione di caustici.

Successful treatment of a case of gastroduodenal necrosis caused by the massive ingestion of muriatic acid is described. Total gastrectomy and resection of the duodenum and head of the pancreas were followed by oesophagocolonjejunoplasty. It is suggested that surgery should be as radical and as early as possible in cases where strong acids have been ingested.

Ascending aorta to femoral arteries bypass without opening the abdominal cavity. Choice treatment in cases of complete occlusion of the infrarenal aorta.

In two cases which needed a revascularization of the inferior limbs, it was possible to utilize the subrenal aorta (the first case was affected by an infrarenal aortic occlusion; the second by an infection of a previously inserted aortofemoral graft), the AA. elected to perform a bypass with a dacron graft between the ascending aorta and femoral arteries according to the technique already proposed by Kaplitt. Having accomplished the proximal anastomoses to the ascending aorta through a midsternal incision, the graft was placed into a properitoneal tunnel down to both inguinal regions. This tunnel was obtained in the anterior abdominal wall by a blind blunt dissection entering the properitoneal space at the inferior end of the sternal incision. In this way the opening of the abdomen is avoided. On account of its poor risk, this procedure is advisable not only in cases of infrarenal aortic occlusion but almost in all aged and poor risk patients who require a revascularization of the inferior limbs.

Aneurysm of the gastroduodenal artery.

A case of aneurysm of the gastroduodenal artery associated with obstruction of celiac axis, is presented. The patient underwent successful surgical correction. The clinical and surgical aspects of this patient are discussed.