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Biomedical subjects

P Palma

Publications and source records attributed to P Palma.

At least 37 records · Page 2Linked to original sources
PubMed2000

Anti-ICAM-1 blockade reduces postsinusoidal WBC adherence following cold ischemia and reperfusion, but does not improve early graft function in rat liver transplantation.

BACKGROUND/AIM: The present in vivo study investigated the impact of a monoclonal antibody directed against the intercellular adhesion molecule-1 (ICAM-1) on initial microvascular reperfusion injury after liver transplantation. METHODS: Orthotopic, syngeneic liver transplantation including arterial reconstruction was performed in male Lewis rats after 24 h graft storage in University of Wisconsin (UW) solution at 4 degrees C. Animals received either an anti-ICAM-1 antibody (n=7), an IgG1 control antibody (n=8) or saline only (n=7). Hepatic microvascular alterations during the initial 90 min of reperfusion were assessed using intravital fluorescence microscopy. Early graft dysfunction was determined by analysis of bile flow. RESULTS: After treatment with anti-ICAM-1 mAb, hepatic microvascular perfusion was found improved when compared with that of IgG1- and saline-treated controls. In addition, anti-ICAM-1 mAb effectively reduced the number of permanently adherent white blood cells in postsinusoidal venules (284.4+/-59.1 mm(-2) vs IgG1: 371.9+/-26.7 mm(-2) and saline: 431.8+/-46.4 mm(-2); p<0.05). In contrast, the number of stagnant white blood cells in sinusoids was higher (p<0.05) in liver grafts with blocked ICAM-1 (320.6+/-17.2 mm(-2)) compared with that of IgG1- (215.2+/-11.1 mm(-2)) and saline-treated controls (226.4+/-14.0 mm(-2)). Measurement of hepatic uptake of fluorescent-labeled latex particles did not reveal significant differences in phagocytic activity. Finally, bile flow also did not differ between the three groups studied. CONCLUSION: Together these results indicate that ICAM-1 is involved in the process that mediates white blood cells adherence in postsinusoidal venules, whereas in hepatic sinusoids other mechanisms apart from ICAM-1-mediated white blood cells adherence seem to be fundamental for posttransplant white blood cells accumulation. Our data further suggest that white blood cells adherence in postsinusoidal venules via ICAM-1 does not make a major contribution to the pathogenesis of early cold ischemia/reperfusion injury after liver transplantation.

Animals↗
PubMed1999

Pathology of the peripheral nervous system.

In this review, the first four papers deal with an important chapter in peripheral nerve surgery: cranial nerve reconstruction after injury occurring during skull base surgery. The last paper discusses the problem of peripheral nerves affected by a ganglion cyst. Damage to a cranial nerve is no longer considered to be an absolutely irreparable event. The first two studies are related to facial nerve management during the surgical treatment of vestibular schwannomas. The most common mechanisms responsible for facial nerve injury during tumor removal and the technical means to avoid them are cited. The importance of intraoperative neurophysiologic monitoring to save the facial nerve is stressed. A comparison between microsurgery and radiosurgery results in the conclusion that for vestibular schwannomas, the first choice of treatment is microsurgery. These two large and exceptional series show that by using a refined technique it is possible to obtain both total tumor removal and preservation of the facial nerve in most of the vestibular schwannomas. In the minority of patients in whom the facial nerve is severed, there are several therapeutic options to re-establish facial nerve function. After facial nerve reconstruction, performed immediately during the same tumor operation, a satisfactory reinnervation was obtained in 74% of the cases. After facial nerve reanimation, using as donor nerve the hypoglossus and performed 1 week after the tumor operation, a satisfactory reinnervation was obtained in 96% of the cases. The other two papers deal with the intraoperative transection of the trochlear and abducens nerve during surgery for skull base tumors. These two cranial nerves, owing to their simply organized motor nerve system (they are purely motor nerves and supply one muscle each), show quite a good expectation of functional recovery. The behavior of ganglion cysts involving peripheral nerves is the topic of the last paper reviewed. These cysts are benign lesions that can cause permanent neurologic deficits of the involved nerve. The etiology, clinical presentation, surgical techniques, and recurrence rate are reported. In the present series, the outcomes after ganglion cyst excision are not as favorable as those reported in other series. Before surgery, patients must be informed about the possibility of residual motor deficits and recurrences.

Journal Article↗
PubMed1998

[Early postoperative complications after different methods of intestinal reconstruction in deep anterior rectum resection--a prospective study].

For the first period after low anterior resection and total mesorectal excision for rectal cancer, the colonic J-pouch is superior to the straight or lateroterminal anastomosis. Despite the simple technique and short stretch of sutures, the LTA is unsuitable due to the high postoperative morbidity and because the reconstruction functions poorly. If the expected anastomis is below 6 cm from the anal verge, i.e. 4 cm above the sphincter muscle, the colonic J-pouch is recommended.

Adult↗
PubMed1997

Video-assisted thoracoscopic truncal vagotomy.

Thoracoscopic truncal vagotomy was performed in three patients with recurrent ulcer after previous Billroth-II gastrectomy. The technique involved double-lumen endotracheal-endobronchial intubation and single-lung ventilation. No morbidity or mortality existed and the mean hospitalization was 7 days. To date, no recurrent ulceration has been detected in these patients. Thoracoscopic truncal vagotomy is considered to be a rapid, simple and safe approach and thus could play a preferential role in the management of patients with recurrent peptic ulcer after previous gastrectomy.

Aged↗
PubMed1996

Intravital studies on beneficial effects of warm Ringer's lactate rinse in liver transplantation.

This quantitative in vivo fluorescence microscopy study investigated the impact of warm versus cold Ringer's lactate (RL) graft rinse on various microvascular manifestations of ischemia-reperfusion injury after liver transplantation in the rat. Syngeneic orthotopic liver transplantation, including arterial revascularization, was performed in male Lewis rats following 24 h of cold storage in University of Wisconsin (UW) solution. In one group (n = 8) liver grafts were rinsed with 4 degrees C (cold) RL, whereas in the other group (n = 8) grafts were rinsed with 37 degrees C (warm) RL immediately prior to revascularization. Hepatic microvascular perfusion, leukocyteendothelium interaction, and Kupffer cell activation were quantified 30-90 min after graft reperfusion by direct visualization with intravital fluorescence microscopy. Moreover, biliary excretory graft function was analyzed by determination of bile flow and bile salt excretion during the first 90 min after reperfusion. Compared to grafts rinsed with cold RL, acinar and sinusoidal perfusion were found to be significantly increased after rinsing the grafts with warm RL. The amount of nonperfused acini declined from 18.1% +/- 4.0% to 7.4% +/- 1.6% (P < 0.05), and the total percentage of perfused sinusoids increased from 80.1 +/- 1.4 to 88.4 +/- 1.2 (P < 0.001) after cold and warm rinse, respectively. After rinsing the graft with warm RL, WBC adherence in sinusoids and especially in postsinusoidal venules decreased significantly by 28% (P < 0.001) and 33% (P < 0.001), respectively. Kupffer cell activation was markedly reduced after rinsing with RL at 37 degrees C, as indicated by a decelerated adherence of latex particles injected 80 min after reperfusion. Excretory graft function was dramatically increased following warm RL rinse during the 90-min observation period. Bile flow was enhanced from 1.04 +/- 0.5 to 3.9 +/- 0.8 ml/100 g liver per 90 min (P < 0.01), with a parallel rise in bile salt excretion from 24.3 +/- 5.8 to 128.0 +/- 19.8 mmol/ 100 g liver per 90 min (P < 0.05) when compared to cold RL. These data strongly suggest that rinsing liver grafts with warm RL prior to reperfusion represents a simple and inexpensive way to reduce the incidence of primary graft failure secondary to ischemia and reperfusion injury in liver transplantation.

Animals↗
PubMed1996

Tailored nasal surgery for normalization of nasal resistance.

The nose acts as a physiologic airway resistor, accounting for around 50% of total airway resistance. Adequate nasal resistance is essential not only for correct functioning of the nose but to ensure normal pulmonary physiology. Pathological nasal resistance is determined by alterations in the shape and volume of the nasal cavities that singly or in association disrupt nasal aerodynamics, a condition that will present mainly in the form of obstructive disorders. The authors advise against considering nasal cavity surgery simply as surgery of the nasal septum. Nasal surgery should be addressed to normalizing the geometry of the nasal cavities in order to restore physiologic nasal resistance. Surgical procedures may be classified as follows: (1) surgery of the medial wall; (2) surgery of the lateral wall; and (3) surgery of the valve area. Septal surgery is systematically performed by the authors using the maxilla-premaxilla approach (MPA). Functional correction of the septum combines mobilization and/or removal of any deranged portion of the bony and/or cartilaginous septum, followed by reconstruction of the septum support, preferably using autogenous septal grafts. When reconstructing the medial wall, great care must be taken with the most important portion of the septum, i.e., the dorso-caudal margin and the cartilaginous elements. We have called this procedure Functional Osteocartilaginous Reconstruction of the Nasal Septum (FORNS). Obstructive swelling of the turbinates is one of the most common causes of nasal obstruction as it alters the shape and reduces the volume of the nasal cavities causing an exponential increase in nasal resistance. With regard to surgery of the lateral wall, the authors firmly believe that mutilating procedures like total inferior turbinectomy can in no way be considered functional surgery of the turbinates. On the contrary, aim of lateral wall functional surgery is not simply to widen the airway, but rather to restore normal aerodynamic contours to the lateral wall in order to prevent turbulence, a phenomenon which will cause increased nasal resistance. To do this, the authors make systematic use of Conservative Submucosal Turbinoplasty (CST). The procedure is designed especially to treat the submucosa since this is the main focus of anatomo-pathological alterations. Nasal valve surgery is one of the most high-risk surgical procedures since scarring, stiffening, or loss of structural support may cause severe and even irreversible damage. Any surgery of the valve area should therefore carry minimum risk of respiratory complications and aesthetic defects. In the light of these principles, the authors propose a valve area correction technique carried out exclusively through the hemitransfixion incision. This approach affords wide access to the whole valve area, allowing the rhino-surgeon to perform a range of corrections on the anatomic sub-units constituting the nasal valve complex. This same approach can be used to place various grafts. The authors propose a "tailored surgery to normalize the nasal resistances," i.e., a systematic surgery to reshape the volume of the various segments of the nasal chambers by repositioning as close to normalcy as possible the disrupted skeletal framework and recontouring streamlined nasal walls.

Airway Resistance↗
PubMed1996

[Modern corrective nasoseptal surgery].

Inner nose surgery should be addressed to normalize the geometry of the nasal cavities in order to restore physiologic nasal resistance. As the nasal septum plays a key role in the form and the function of the nose, a successful rhinosurgeon must be able to deal with all septal problems ranging from localized spurs to severely traumatized or surgically damaged nasal septa. Nasal airway obstruction due to septal derangements cannot be successfully solved simply by submucous resections of septal window(s) but does often require a range of corrective maneuvers on the anatomic sub-units constituting the septum. Septal surgery is systematically performed by the Authors using the maxilla-premaxilla approach (MPA) which allows access to and manipulation of the entire nasal septum including the caudal and anterior septal margins, columella, upper lateral cartilages, inferior nasal spine as well as floor of the nasal cavities and maxillary crest areas. Correction of the septum combines mobilization and/or removal of any deranged portion of the bony and/or cartilaginous septum, followed by reconstruction of the septum support, preferably using autogenous septal grafts. Reconstruction procedures are designed to reconstitute a stable medial wall and at the same time minimize scar tissue formation. Reconstruction is indispensable to avoid septal flapping occurring when the medial wall consists of muco-periosteal tissue only without firm intermediary support. When reconstructing the medial wall, great care must be taken with the most important portion of the septum, i.e. the dorso-caudal margin and the cartilaginous elements. However, many common nasal problems require procedures to correct the inside of the nose and the external pyramid at the same time. To effectively and efficiently address the challenge posed by the combination of internal and external nasal problems, a thorough understanding of respiratory rhinology as well a familiarity with the many procedures involved in both extensive septal surgery and external nasal pyramid surgery are imperative for the modern-day rhinosurgeon.

Humans↗
PubMed1994

Timing of arterialization in liver transplantation.

OBJECTIVE: This study analyzed the pathophysiologic sequela of different modes of graft reperfusion in liver transplantation. SUMMARY BACKGROUND DATA: The grafted liver may be reperfused either immediately after completion of portal anastomosis followed by delayed arterial reconstruction or simultaneously by portal and arterial blood if all vascular anastomoses are completed during the anhepatic period. METHODS: Delayed arterialization, that is, arterial reperfusion 8 minutes after portal revascularization (n = 12), was compared with simultaneous arterialization (n = 8) using the model of syngeneic orthotopic liver transplantation in male Lewis rats. After cold storage for 24 hours in University of Wisconsin (UW) solution, intravital fluorescence microscopy was employed 30 to 90 minutes after reperfusion to assess hepatic microvascular perfusion, leukocyte accumulation, and phagocytic activity of Kupffer cells. RESULTS: Compared with delayed arterialization, the number of both nonperfused acini and nonperfused sinusoids was reduced after simultaneous reperfusion by 71% (p = 0.008) and 78% (p < 0.001), respectively. Leukocyte accumulation in sinusoids and postsinusoidal venules after simultaneous arterialization decreased by 17% (p = 0.01) and 64% (P < 0.001), respectively. In addition, simultaneous revascularization was able to attenuate Kupffer cell activation, indicated by significantly slower adherence of latex beads injected 80 minutes after reperfusion. Improved hepatocellular excretory function after simultaneous arterialization was demonstrated by increased bile flow during the observation period of 90 minutes after reperfusion (2.24 +/- 0.7 vs. 0.95 +/- 0.4 mL/100 g liver [mean +/- SEM], p < 0.05). CONCLUSIONS: Timing of arterial reperfusion in liver transplantation may be of critical importance in the prevention of various manifestations of reperfusion injury.

Animals↗
PubMed1994

Effects of warm Carolina rinse on microvascular reperfusion injury in rat liver transplantation.

Recently, it has been demonstrated that the use of both cold Carolina rinse (CR, 4 degrees C) as well as warm Ringer's lactate (RL, 37 degrees C) attenuates microvascular perfusion failure and leukocyte (WBC) accumulation in liver grafts. The aim of this study was to analyse in vivo whether warming of CR can also lead to a reduction in microvascular reperfusion injury in rat liver transplantation. Syngeneic orthotopic liver transplantation, including arterial reconstruction, was performed in male Lewis rats (180-300 g). Livers were stored in University of Wisconsin (UW) solution for 24 h and rinsed with 15 ml CR which was either cold 4 degrees C (n = 7) or warm 37 degrees C (n = 8) prior to reperfusion. Hepatic microcirculation and WBC accumulation were assessed by intravital fluorescence microscopy, and graft function was determined by analysis of bile flow during the 90-min reperfusion period. Warm CR yielded significantly (P < 0.01) improved sinusoidal perfusion when compared with cold CR; however, the extent of WBC adherence in both sinusoids and postsinusoidal venules did not vary between the groups. In addition, bile flow was slightly increased after warm CR. We conclude that after 24 h of cold storage in UW solution, warming of CR may offer additional benefit in the prevention of microcirculatory reperfusion injury without affecting WBC accumulation.

Adenosine↗
PubMed1993

Effects of Carolina rinse and adenosine rinse on microvascular perfusion and intrahepatic leukocyte-endothelium interaction after liver transplantation in the rat.

Flushing hepatic grafts immediately before revascularization with a specially designed rinse solution such as "Carolina rinse" has been reported to improve survival after liver transplantation in the rat. This study investigated the influence of Carolina rinse and adenosine rinse on early graft function, microcirculation, and leukocyte (WBC)-endothelial cell interaction of arterialized syngeneic orthotopic liver transplants in Lewis rats. Livers were preserved for 24 hr in University of Wisconsin solution and flushed immediately before reperfusion with either Ringer's lactate (group A: n = 7), Ringer's lactate + 0.2 mmol/liter adenosine (group B: n = 6), or Carolina rinse (group C: n = 7). Microvascular perfusion and WBC accumulation were assessed by intravital fluorescence microscopy. In group C, acinar perfusion was significantly improved, accompanied by a lower percentage of nonperfused sinusoids 1 hr after reperfusion (mean +/- SEM: 26 +/- 2% [group A], 21 +/- 2% [B], 11 +/- 1% [C], P < 0.01 for C vs. A or B). In addition, Carolina rinse and, to a lesser extent, adenosine rinse reduced the number of WBC sticking in sinusoids and postsinusoidal venules. Better graft function in group C was indicated by increased bile flow during the observation period of 90 min after reperfusion (0.5 +/- 0.3 ml/100 g liver [group A], 1.5 +/- 0.7 [B], 3.7 +/- 0.6 [C], P < 0.01 for C vs. A or B). We conclude that Carolina rinse is able to improve early excretory hepatocellular function, microvascular perfusion, and intrahepatic WBC accumulation after prolonged cold ischemia and reperfusion, but adenosine is unlikely to be the key component of this rinse solution.

Adenosine↗
PubMed1993

Differential impact of Carolina rinse and University of Wisconsin solutions on microcirculation, leukocyte adhesion, Kupffer cell activity and biliary excretion after liver transplantation.

This quantitative in vivo fluorescence microscopy study investigated the relative impact of an optimized rinse solution (warm Carolina rinse) and that of an established storage solution (University of Wisconsin solution) on various pathomechanisms of hepatic reperfusion injury after cold storage. Syngeneic orthotopic, arterialized liver transplantation was performed in male Lewis rats after 24 hr of cold ischemia (n = 24). The four experimental groups differed according to the type of preservation/rinse solution used: University of Wisconsin solution/albumin rinse (group 1), autologous blood (just external cooling)/albumin rinse (group 2), blood/Carolina rinse (group 3) and University of Wisconsin solution/Carolina rinse (group 4). Hepatic microvascular perfusion, leukocyte accumulation and phagocytic activity of Kupffer cells were assessed by means of intravital fluorescence microscopy 30 to 90 min after reperfusion. Disturbances of microvascular perfusion were most pronounced in group 2, markedly reduced by University of Wisconsin solution (group 1) and Carolina rinse (group 3) and minimized by combined use of University of Wisconsin solution and Carolina rinse in group 4. Intrahepatic leukocyte-endothelium interaction in sinusoids and postsinusoidal venules was found to depend on the application of Carolina rinse before reperfusion rather than the use of University of Wisconsin solution during cold storage. Activation of phagocytosis by Kupffer cells was most pronounced in group 1, intermediate in groups 2 and 3 and not noticeable in group 4. Hepatocellular excretory function as assessed on the basis of total bile flow and excretion of bile acids during the first 90 min after reperfusion was found to be improved by application of Carolina rinse, both after storage in blood or in University of Wisconsin solution.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗