PubMed Health⌕ Search

Biomedical subjects

F Michelassi

Publications and source records attributed to F Michelassi.

84 records · Page 5Linked to original sources
PubMed1987

Pulmonary and systemic contribution to canine tracheobronchial blood flow.

To investigate the quantity and pathophysiological relationship of pulmonary and bronchial artery supply to the tracheobronchial tree in dogs in absence and in presence of increased tissue metabolic requirements, pulmonary and bronchial blood flow to the trachea and bronchi was determined by the radioactive microsphere method in nine adult mongrel dogs. Microspheres were injected into the right atrium of three dogs (pulmonary injection group) and into the left ventricle of four dogs (systemic injection group) just before and three, eight and fourteen days after resection and anastomosis of the right main bronchus. The remaining two dogs served as controls without surgery. After the fourth injection, the tracheobronchial tree was harvested, divided into segments, and the radioactivity counted in each segment. At baseline the systemic flow to the tracheobronchial tree expressed as percentage of cardiac output was 0.188% +/- 0.121 and the pulmonary blood flow was 0.007% +/- 0.004 (mean +/- S.D.). Three, eight and fourteen days after transection and anastomosis of the right main stem bronchus, the systemic blood flow to the bronchial segments proximal and distal to the anastomosis increased significantly whereas pulmonary blood flow did not change. Depending on the anatomical segment considered the systemic contribution was between 5 and 100 times larger than the pulmonary one, both at baseline and after transection and anastomosis of the right main stem bronchus, but the ratio diminished in more distal segments where pulmonary blood flow was larger. It is concluded that the systemic blood contribution to the canine tracheobronchial tree is larger than the pulmonary one and that, in the presence of increased metabolic needs, it responds more promptly with increased blood flow.

Animals↗
PubMed1986

Cyclooxygenase blockade elevates leukotriene E4 production during acute anaphylaxis in sheep.

We examined changes in the levels of eicosanoids in blood and pulmonary lymph of anesthetized sheep undergoing acute anaphylaxis. Within 1-3 min of intravenous antigenic challenge of previously sensitized sheep, there were approximately 7-30-fold elevations in mean arterial plasma levels of thromboxane B2 and 6-ketoprostaglandin F1 alpha, respectively, as measured by RIA. Negligible changes in levels of these cyclooxygenase products were found in both nonsensitized sheep and in sensitized sheep treated with indomethacin before antigenic challenge. In contrast, no changes in levels of sulfidopeptide leukotrienes (SPLT) in pulmonary lymph were detectable by RIA during anaphylaxis in sensitized or nonsensitized sheep, but levels of SPLT in indomethacin-treated sensitized sheep increased more than fivefold above levels in lymph from both other groups of animals. The immunoreactive SPLT in lymph from indomethacin-treated sheep was accounted for as LTE4, as demonstrated by mobility on HPLC and absorbance at 280 nm. These results support the possibility that certain undesirable effects of nonsteroidal antiinflammatory drugs, such as cardiopulmonary reactions in aspirin-sensitive individuals, and impaired renal and cardiac function during therapy with these drugs, may be related in part to augmented synthesis of the 5-lipoxygenase pathway products, especially those of the sulfidopeptide class. Increased LT production could also limit the antiinflammatory effectiveness of these drugs in many disease states.

6-Ketoprostaglandin F1 alpha↗
PubMed1986

Complications of tracheal reconstruction. Incidence, treatment, and prevention.

Between 1962 and 1982, 416 primary tracheal reconstructions and 21 staged reconstructions were performed. Since then 80 additional tracheal reconstructions have been accomplished (to April of 1985). The first 20 years of our experience (1962 to 1982) have been scrutinized to identify complications and describe their management in patients operated on for tumors or postintubation lesions only. Because the series includes all cases, commencing in 1962 when tracheal surgery was not well developed, many complications reflect a learning experience. The first and second halves of the series have therefore been compared. Measures to prevent complications are discussed.

Granulation Tissue↗
PubMed1985

Bile duct disruption by blunt trauma.

The rarity of bile duct injury secondary to blunt abdominal trauma leads to frequent delays in diagnosis and inappropriate management. An illustrative case is therefore described and 94 reported cases are reviewed. In 53% of patients, operation was delayed more than 24 hours. Early clinical findings of hypovolemia and acute abdomen are related to associated injuries. Late findings are abdominal distention and jaundice due to the biliary injury. Early diagnosis is facilitated by diagnostic paracentesis. Patients operated on during the first 24 hours after the injury had a statistically higher incidence of bile duct injury distal to the cystic duct (p less than 0.05) and of complete ductal severance (p less than 0.05). The association of location distal to the cystic duct and complete severance was highly significant (p less than 0.001). Management should include biliary exploration. Cholangiography using concentrated water-soluble contrast agents may help to find the anatomy of obscure injuries. The choice of surgical repair must be individualized according to the location and the magnitude of the injury.

Abdomen, Acute↗
PubMed1983

Transduodenal sphincteroplasty. 5-25 year follow-up of 89 patients.

Between 1957 and 1977, 95 patients underwent transduodenal pancreatic sphincteroplasty (TPS) for a diagnosis of recurrent pancreatitis. Five to twenty-five year follow-up was obtained for 89 patients (94%) and was analyzed by life-table method. Short-term successful outcome was defined as relief of symptoms (e.g., pain) for one to three years; long-term successful outcome was defined as those patients who remained symptom-free at time of last follow-up. Operative mortality was 4.2% (4 patients). Fifty-six patients (66%) had a successful short-term outcome. Of these, 13 patients had recurrence of symptoms: 7 occurred at 4 years, 5 at 5 years and 1 at 6 years. Preoperative factors associated with poor short-term outcome were previous upper abdominal surgery (X2 = 5.67, p less than 0.05) and frequent diarrhea (X2 = 6.18, p less than 0.05). Preoperative factors associated with poor long-term outcome were previous upper abdominal surgery (X2 = 7.82, p less than 0.01), heavy alcohol intake (X2 = 4.71, p less than 0.05), narcotic use (X2 = 5.68, p less than 0.05) and frequent diarrhea (X2 = 4.8, p less than 0.05). Morphine Prostigmin Test (MPT) was performed preoperatively in 78 patients (82%). A significantly greater proportion of patients with a rise in serum pancreatic enzymes secondary to MPT (MPT+) had a successful long-term outcome compared with those without such a rise (MPT-) (61% v 41%, X2 = 5.13, p less than 0.05). Furthermore, of the patients with a successful short-term outcome, 88% with MPT+ remained long-term symptom-free compared to 38.5% with MPT- (X2 = 8.36, p less than 0.01). We conclude that TPS can be a successful operation for acute recurrent pancreatitis. Previous upper abdominal operations, signs of more advanced pancreatic disease, preoperative narcotic use and alcohol abuse, were associated with a worse outcome and probably associated with chronic recurrent pancreatitis. Preoperative use of MPT, coupled with accurate clinical history, defined groups with different short- and long-term prognosis after TPS.

Abdomen↗
PubMed1983

Effects of leukotrienes B4 and C4 on coronary circulation and myocardial contractility.

Arachidonic acid is metabolized to prostaglandins and thromboxane via the cyclooxygenase pathway and to leukotrienes B4, C4, D4, and E4 via the lipooxygenase pathway. A possible role played by leukotrienes in cardiogenic shock resulting from anaphylaxis prompted us to investigate the action of these compounds on coronary vessels and myocardial contractility. In this study leukotriene B4 (LTB4) and C4 (LTC4) were injected directly into the left circumflex (LCx) coronary artery of nine anesthetized Suffolk sheep. LTB4 had no effect on coronary artery blood flow or myocardial contractility, but 3 X 10(-9) mole induced profound transient circulating neutropenia, reflecting the potent chemotactic and chemokinetic properties of this compound. Injecting as little as 1.6 X 10(-11) mole of LTC4 caused a 14.5 +/- 4.3% (mean +/- SE) reduction of LCx coronary artery flow while 1.6 X 10(-10) mole caused a 26.5 +/- 3.7% decrease of LCx coronary artery flow and an 18.1 +/- 3.2% decrease in systolic shortening of the myocardial region supplied by the LCx coronary artery. Since the decrease in systolic shortening was far greater than that expected on the basis of the reduction in coronary artery flow, we postulate that LTC4 has a direct negative inotropic effect. FPL 55712, a receptor antagonist of leukotrienes C4, D4, and E4, blocked the vasoconstriction induced by LTC4 but only partially blocked the negative inotropic effects of LTC4. LTC4 is a potent vasoconstrictor and negative inotropic agent and may play an important role in anaphylactic shock.

Animals↗
PubMed1982

Leukotriene D4: a potent coronary artery vasoconstrictor associated with impaired ventricular contraction.

Leukotriene D4 (2 c 10(-9) mole), injected into the left circumflex coronary artery of anesthetized sheep, produced profound coronary vasoconstriction and impaired regional ventricular wall motion. This cardiac effect was neither inhibited by prior treatment of the sheep with a cyclooxygenase inhibitor nor associated with thromboxane B2 release into the coronary sinus. Intravenous FPL 55712 completely abolished the coronary vasoconstriction of leukotriene D4, but a significant reduction of regional wall shortening persisted.

Animals↗
PubMed1981

Regional lymph node dissection for malignant melanoma of the extremities.

Seven hundred thirty-nine patients with malignant melanoma of the extremities were treated with a uniform surgical approach that included wide and deep excision of the primary site and regional node dissection therapeutically and electively for invasive lesions (Clark's levels III, IV, and V). Of the 490 patients who underwent lymph node dissections, follow-up was available for 457 (93%). Life-table comparison of 362 patients with histologically negative nodes to 95 with histologically proved lymph node metastases yielded statistically significant differences in survival (P less than 0.001). Five-year cumulative survival rates were 91% in the group without and 48% in the group with nodal metastases. Among histologically positive patients, differences in life-table survival curves for the 60 clinically negative patients compared to the 35 clinically positive patients were also statistically significant (P = 0.004); 5-year cumulative survival rates were 57% for the former group and 33% for the latter. Although there appears to be an advantage to regional lymph node dissection for micrometastases as opposed to gross nodal involvement, for the majority of patients metastatic melanoma in these nodes is the major indicator of systemic disease.

Actuarial Analysis↗
PubMedDate not supplied

Long-term prospective assessment of functional results after proctectomy with coloanal anastomosis.

The objective of this study was to prospectively assess the long-term functional results after restorative proctectomy with coloanal anastomosis for rectal cancer. Thirty consecutive patients (18 males; mean age 59.6 +/- 9.8 years, range 40 to 75 years) underwent proctectomy with coloanal anastomosis for rectal cancer between January 1990 and March 1997. Cancers were located between 5 and 12 cm from the anal verge. Differences existed in the administration of adjuvant therapy and in the kind of anastomotic reconstruction. An 8 cm colonic J-pouch was fashioned in 11 patients. The coloanal anastomosis was protected by a diverting loop ileostomy in 22 patients. All patients were evaluated using a prospective patient-completed protocol to record daily bowel activity over a 1-week period at 3, 6, and 12 months, and yearly thereafter. Mean follow-up extends to 55.5 +/- 27 months (range 7 to 117 months). There were no perioperative deaths. Four patients (13.3%) developed a clinically evident anastomotic dehiscence. Overall, stool frequency decreased from 4.4 +/- 2.5 bowel movements per day at 3 months to 3.0 +/- 2.8 bowel movements per day at 5 years. Patients with a J-pouch had a lower stool frequency in comparison to patients with an end-to-end coloanal anastomosis during the entire study period (from 3.2 +/- 2.2 vs. 3.9 +/- 2.7 bowel movements per day at 6 months to 2.8 +/- 1.9 vs. 3.4 +/- 4.0 bowel movements per day at 5 years; no statistical significance). The percentage of continent patients increased from 50% at 6 months to 75% at 5 years; the percentage of patients with incontinence for solid stool and with frequent incontinence (&dollar;7 episodes per week) decreased from 35.7% at 6 months to 12.5% at 5 years. The influence of the type of anastomosis, dehiscence, protective stoma, J-pouch, radiation therapy, and gender was evaluated with univariate analysis. Although there was no statistically significant correlation between any of these variables and the development of incontinence, when incontinence occurred, a history of anastomotic dehiscence increased the number of episodes of incontinence per week and the percentage of episodes of incontinence for solid stools at 6 months, 2 years, and 5 years (P < 0.05 and P < 0.001, respectively); the use of preoperative radiation therapy increased the number of episodes of incontinence per week at 6 months, 1 year, 2 years, and 5 years (P < 0.01) and the percentage of episodes of incontinence for solid stools at 3 and 6 months and 1 and 2 years (P < 0.04); and the presence of a J-pouch increased the number of episodes of incontinence per week at 1 and 2 years (P < 0.03 and 0.005, respectively) and the percentage of episodes of incontinence for solid stools at 2, 3, and 4 years (P < 0.05). These data suggest that the functional results after proctectomy with coloanal anastomosis improve at least over the course of the first 5 postoperative years. Furthermore, when incontinence develops, its severity is made worse by the occurrence of an anastomotic dehiscence, the use of preoperative radiation therapy, and the presence of a J-pouch.

Adult↗