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Biomedical subjects

S Post

Publications and source records attributed to S Post.

At least 37 records · Page 2Linked to original sources
PubMed1998

[New data on recurrence rate of Crohn disease].

Despite numerous studies on the recurrence rate and risk factors following operations for Crohn's disease, unequivocal evidence on how to prevent recurrence non-medically and on the specific risks is lacking. Just two recommendations are supported by sufficient data: Do not perform radical resections with wide margins of safety and try to prevent the patient from smoking. Further studies are needed to delineate high risk subgroups for specific pharmacological interventions postoperatively.

Anastomosis, Surgical↗
PubMed1998

[Ambulatory co-disciplinary risk-adjusted preoperative care].

Routine preoperative studies in asymptomatic patients are not helpful for perioperative risk evaluation, and the cost is considerable. The decision regarding the status of a patient for elective surgery can be accurately predicted in 95% of cases on the basis of a complete history and physical examination alone; selective testing should be preferred. Interdisciplinary outpatient premedication is suitable for an individual risk evaluation, and a significant reduction in cost and inpatient treatment.

Adult↗
PubMed1997

Extrahepatic biliary obstruction impairs microvascular perfusion and increases leukocyte adhesion in rat liver.

To determine if disturbances of the liver microcirculation may be of pathophysiological relevance for liver damage during acute biliary obstruction, we studied the effects of bile duct ligation (BDL) on hepatic microhemodynamics and leukocyte adhesion in rat liver in vivo. Male Wistar rats were subjected to BDL for 3 days and 7 days, respectively. Sham-operated controls underwent laparotomy without BDL. After 3 days, intravital fluorescence microscopy (IVM) and hydrogen gas (H2) clearance were performed to study hepatic microvascular perfusion. Furthermore, leukocyte-endothelial cell interactions were assessed by IVM. Intercellular adhesion molecule 1 (ICAM-1) protein expression was studied by Western blot analysis and tissue immunofluorescence after 3 and 7 days, respectively. Analysis of microvascular perfusion by IVM revealed a marked impairment of sinusoidal perfusion after 3 days. Assessment of H2 clearance confirmed that overall hepatic microvascular perfusion was decreased. In addition, increased leukocyte adhesion in sinusoids and venules could be observed. A concomitant increase of ICAM-1 expression in liver tissue was also noted within the first week after BDL. Our results show that BDL is followed by a marked depression of the hepatic microcirculation and increased leukocyte adhesion in vivo within 3 to 7 days. Together, these findings suggest that deficits in microvascular perfusion and increased neutrophil infiltration may represent a potential source of liver injury during acute biliary obstruction.

Animals↗
PubMed1997

[Against the principle surgical indications in inguinal hernia].

It is generally accepted that most inguinal hernias should be operated electively. This study presents a risk calculation challenging this view. Three strategies are presented: prophylactic indication on principle (A), elective operation in every second case (B), and operation in case of strangulation only (C). On the basis of available epidemiological data it is calculated that, for the male German population aged 65 years and over 69,954 (A), 36,292 (B), and 2630 (C) inguinal hernia repairs would be necessary annually; 167 (A), 145 (B) and 123 (C) perioperative deaths would occur, connected with 1702 (A), 1373 (B) and 1048 (C) years of life lost, respectively. Thus, operation of every inguinal hernia would result in a (small) reduction of life expectancy. These data provide evidence that in elderly patients the indication for operative treatment of inguinal hernias should depend upon symptoms and suffering. There is no reason to operate on asymptomatic patients because of a presumed risk of strangulation.

Aged↗
PubMed1997

Inhibition of nitric oxide synthesis in ischemia/reperfusion of the rat liver is followed by impairment of hepatic microvascular blood flow.

BACKGROUND: Recent studies provide evidence that nitric oxide (NO) has beneficial effects in hepatic ischemia/reperfusion injury. The purpose of this study was to evaluate whether nitric oxide is involved in the regulation of hepatic microvascular perfusion after warm hepatic ischemia. Therefore, we performed a study using in vivo fluorescence microscopy. METHODS: Clamping of the left liver lobe was performed in male Wistar rats for the duration of 70 min. One experimental group (n=8) received L-NAME (Nw-nitro-L-arginine methyl ester hydrochloride), an NO-synthase inhibitor, 1 min prior to reperfusion. A second experimental group (n=8) received L-arginine (NO-substrate) continuously infused throughout the observation period. Controls (n=8) received equivalent volumes of an isotonic solution and underwent the same procedures. Hepatic microvascular blood flow and leukocyte-endothelial cell interaction was studied between 20 and 90 min after reperfusion using in vivo fluorescence microscopy. RESULTS: Inhibition of NO-synthesis during reperfusion by application of L-NAME caused a marked decrease in sinusoidal blood flow velocity. Furthermore, we noted an increase of non-perfused sinusoids in this group. Treatment with L-arginine improved functional perfusion of hepatic acini and reduced significantly the number of adherent leukocytes in sinusoids and venules compared to control animals. CONCLUSIONS: Our results provide further evidence that NO maintains postischemic hepatic microvascular perfusion and that inhibition of NO synthesis has detrimental effects on hepatic microhemodynamics during reperfusion.

Animals↗
PubMed1997

Degree of carotid artery stenosis. Comparison of selective and non-selective angiographic findings with surgical specimens.

OBJECTIVE: To compare the degree of vessel narrowing seen on selective and non-selective carotid artery catheter angiograms using criteria set by NASCET and ECST with the results obtained from corresponding surgical specimens. SUBJECTS: In 40 preoperative angiograms (20 non-selective, 20 selective) the 'distal' degree of internal carotid artery (ICA) stenosis according to NASCET criteria and the 'local' degree of stenosis according to ECST criteria was assessed. These data were compared with the 'distal' and 'local' degree of ICA stenosis obtained by measuring the specimens and the diameter of the distal ICA intraoperatively. RESULTS: The median 'local' degree of stenosis was 86.5% in the specimen and 83.5% in the selective angiograms (difference not significant). In non-selective angiography the median 'local' degree of stenosis was 77.5% compared to 84% in the corresponding specimens (P < 0.01). The median 'distal' degree of stenosis in selective angiography was 76.5 versus 75.5% in the specimens (n.s.). The median 'distal' degree of non-selective angiography was 67% compared to 77.5% in the corresponding specimens (P = 0.02). The trend to underestimate high grade stenosis (above 90%) was more pronounced in non-selective than in selective angiography. Medium grade stenosis (60-80%) was slightly overestimated in selective angiography. CONCLUSION: Selective angiography is more accurate in determining the 'true' degree of stenosis in internal carotid artery disease, taking into account a slight overestimation of medium grade stenosis. High grade stenosis is underestimated in both selective and non-selective angiography. These observations extend to both the ECST and NASCET criteria of measuring the degree of stenosis, which differ by about 10%.

Aged↗
PubMed1997

Effects of mixed ETA and ETB-receptor antagonist (Ro-47-0203) on hepatic microcirculation after warm ischemia.

There is evidence that endothelin (ET) is involved in disturbances of the hepatic microcirculation after warm ischemia. In this study we investigated the influence of a mixed ETA-, ETB-receptor antagonist (Bosentan) on ischemia-reperfusion damage of the liver by means of intravital fluorescence microscopy (IVM). Clamping of the left liver lobe (= warm ischemia) was performed in 16 male Wistar rats for 70 min. The treatment group (N = 8) received 15 mg/kg Bosentan (Ro-47-0203) 1 min prior to reperfusion. Controls (N = 8) received an equivalent amount of Ringer's solution. Between 20 and 90 min after reperfusion, leukocyte-endothelial cell interactions in sinusoids and postsinusoidal venules as well as perfusion of hepatic acini were studied. Application of Bosentan improved sinusoidal blood flow, attenuated manifestations of microvascular perfusion failure, and decreased the number of rolling leukocytes in postsinusoidal venules. Our results provide further evidence that ET is involved in postischemic impairment of hepatic microhemodynamics during reperfusion.

Animals↗
PubMed1997

Clostridial gas gangrene of the abdominal wall after laparoscopic cholecystectomy.

Laparoscopic cholecystectomy is associated with a considerable rate of infectious complications of up to 2.8%. Such infections are usually of minor clinical importance. However, we observed a case of life-threatening Clostridial gas gangrene centering around the right lateral port site and developing across all of the right-sided abdominal wall, causing septic shock and severe multi-organ failure. Considering the overall infection rate and the possibility of even severe morbidity, we advocate perioperative antibiotics in laparoscopic cholecystectomy.

Abdominal Muscles↗
PubMed1996

Impact of N-acetylcysteine on the hepatic microcirculation after orthotopic liver transplantation.

Recent observations showed an improvement of hepatic macro- and microhemodynamics as well as survival rates after warm ischemia of the liver following treatment with N-acetylcysteine (NAC). In this study we assessed the influence of NAC on the hepatic microcirculation after orthotopic liver transplantation (OLT) using intravital fluorescence microscopy. OLT with simultaneous arterialization was performed in 16 male Lewis rats following cold storage in University of Wisconsin solution for 24 hr. Within the experimental group (n = 8) donors received NAC (400 mg/kg) 25 min before hepatectomy. In addition, high-dose treatment of recipients with NAC (400 mg/kg) was started with reperfusion. Control animals (n = 8) received an equivalent amount of Ringer's solution. Intravital fluorescence microscopy was performed 30-90 min after reperfusion assessing acinar and sinusoidal perfusion, leukocyte-endothelium interaction, and phagocytic activity. Treatment with NAC reduced the number of nonperfused sinusoid from 52.4 +/- 0.8% to 15.7 +/- 0.5% (p = 0.0001) (mean +/- SEM). Furthermore, we achieved a significant reduction of leukocytes adhering to sinusoidal endothelium (per mm2 liver surface) from 351.9 +/- 13.0 in controls to 83.6 +/- 4.2 in the experimental group (P = 0.0001). In postsinusoidal venules, treatment with NAC decreased the number of sticking leukocytes (per mm2 endothelium) from 1098.5 +/- 59.6 to 425.9 +/- 37.7 (P = 0.0001). Moreover, bile flow was significantly increased after therapy with NAC (4.3 +/- 1.2 vs. 2.2 +/- 0.7 ml/90 min x 100g liver) (P < 0.05). Phagocytic activity was not influenced by application of NAC. We conclude that high-dose therapy with NAC in OLT attenuates manifestations of microvascular perfusion failure early after reperfusion and should be considered as a means to reduce reperfusion injury.

Acetylcysteine↗
PubMed1996

Pedal bypass for limb-threatening ischaemia: an 11-year review.

Fifty-six patients with limb-threatening ischaemia had pedal revascularization with either autologous vein (n = 39) or sequential composite graft with a 6-mm polytetrafluoroethylene prosthesis and autologous vein (n = 17); 75 per cent had gangrene and skin necrosis and 25 per cent had ischaemic rest pain alone. Twelve grafts occluded within the first week, and resulted in major amputation in eight patients after unsuccessful revision. Two patients required amputation for persistent ischaemia despite a patent bypass. One patient died from bowel perforation (2 per cent). In 47 (84 per cent) of the 56 patients limb and life were preserved. The primary patency rate after 1, 2 and 4 years was 65, 55 and 55 per cent respectively, the secondary patency rate was 71, 62 and 62 per cent, and cumulative limb salvage rates were 77, 71 and 66 per cent. Life-table survival rates during follow-up (median 25 (range 0-112) months) were 89, 78 and 52 per cent respectively after 1, 2 and 4 years. Thirteen of 21 patients who died during follow-up did not require major amputation. Pedal reconstruction with autologous vein provides limb salvage until death in nearly two-thirds of patients with critical limb ischaemia resulting from crural arterial occlusive disease.

Adult↗
PubMed1996

Role of microcirculatory derangements in manifestation of portal triad cross-clamping-induced hepatic reperfusion injury.

Postischemic liver dysfunction following portal triad cross-clamping (PTC) predisposes patients for the development of multiple system organ failure (MSOF) and is associated with increased mortality of MSOF. The deterioration of the hepatic microcirculation may play a pivotal role in the pathophysiologic sequelae of PTC-induced reperfusion injury. We quantitatively analyzed in vivo the role of microcirculatory derangements in the manifestation of hepatic reperfusion injury following ischemia by PTC. Sprague-Dawley rats were subjected to 20 min PTC followed by 60 min reperfusion (PTC, n = 18). Sham-operated animals without ischemia served as controls (sham, n = 15). Within 45-60 min of reperfusion, hepatic microcirculation (sinusoidal perfusion, leukocyte-endothelial cell interaction) was analyzed by means of intravital fluorescence microscopy; tissue oxygenation was assessed using a platinum multiwire surface electrode. Liver enzymes and bile flow were determined as indicators of hepatocellular integrity and liver function. In vivo analysis of postischemic hepatic microcirculation revealed the induction of leukocyte-endothelial cell interaction within sinusoids and postsinusoidal venules and concomitant sinusoidal perfusion deficits associated with tissue hypoxia. In addition, PTC resulted in increased serum levels of liver enzymes and a marked reduction of bile flow. Regression analyses demonstrated significant correlations between hepatocellular desintegration/liver dysfunction and PTC-induced microcirculatory disorders. These results underline the predominant role of microcirculatory disturbances in the development of PTC-induced hepatic reperfusion injury and support the concept that normalization of postischemic microcirculation may be a most effective therapeutic regimen to prevent hepatocellular damage and liver dysfunction.

Animals↗
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

[Manually assisted laparoscopic surgery--realistic evolution of the minimally invasive therapy concept? Initial experiences with the "Endohand"].

The essential limitations of laparoscopic procedures--lack of palpation, problematic retrieval of specimen and anastomosis, etc.--are abolished by the hand of the surgeon, which is inserted into the peritoneal cavity through a mini-laparotomy. While holding the pneumoperitoneum, the hand acts as an intelligent instrument performing surgical exploration, exposition of the field of operation, blunt dissection or intracorporal knot-tying. The mini-laparotomy is used to insert conventional instruments and suture material, as well as for specimen retrieval and anastomosis. Our preliminary experience (3x splenectomy, 2x sigmoid colectomy, 1x anterior resection of rectum, 1x proctocolectomy with J-pouch) shows that even extensive laparoscopic operations are accomplished much more simply. The time spent for such procedures is markedly reduced.

Adult↗
PubMed1996

[The accuracy of angiography and CT angiography of the carotid bifurcation compared to macro-morphological correlation].

PURPOSE: To compare the degree of carotid artery stenosis in angiography and CT angiography with the degree of stenosis measured in an intact eversion endarterectomy specimen. METHODS: Preoperative angiograms (intraarterial DSA, 512 x 512 matrix) and CT-angiograms (24 sec spiral scan, slice thickness 2 mm, pitch 1.5) were taken in 12 patients with symptomatic carotid stenosis. Evaluation of the degree of stenosis was performed according to the NASCET ("distal" degree) and ECST ("local" degree) methods. These data were compared with measurements of the surgical specimens. RESULTS: The median "local" degree of stenosis in angiograms was 81.5% (range: 70-99%), in CT angiograms 83% (59-94%) and in specimens 85.5% (65-96%). The "distal" degree of stenosis was 79% (50-99%) in angiograms, 85.5% (55-99%) in CT angiograms and 81% (52-95%) in specimens. CT angiography slightly overestimated the degree of stenosis compared with the specimen, whereas angiography slightly underestimated the true degree of stenosis. However, these differences were not statistically significant. CONCLUSION: CT angiography is able to predict the degree of internal carotid stenosis when compared with an intact surgical specimen. It is as accurate as the "gold standard" of invasive angiography.

Angiography, Digital Subtraction↗
PubMed1996

The impact of disease pattern, surgical management, and individual surgeons on the risk for relaparotomy for recurrent Crohn's disease.

OBJECTIVE: The authors provide a multivariate analysis of a large single-center experience with limited surgery for Crohn's disease. SUMMARY BACKGROUND DATA: During the past decade, the aim of surgery for Crohn's disease has shifted from radical operation, achieving inflammation-free margins of resection, to "minimal surgery," intended to remove just grossly inflamed tissue or performing strictureplasties. METHODS: Seven hundred ninety-three cases of resection and/or strictureplasty in 689 individuals with histologically verified Crohn's disease were followed for a mean period of 50 months (range, 5-166 months). Two different end points were analyzed: 1) any relaparotomy for recurrent (or persistent) Crohn's disease and 2) relaparotomy for site-specific recurrence. More than 30 variables of patient/disease characteristics and surgical management were included in a proportional hazard model. RESULTS: Five parameters were associated independently with the risk for relaparotomy: increased risk coincided with young age at onset of disease, involvement of jejunum, enterocutaneous fistula, or performed strictureplasty, and decreased risk followed ileocecal resection. Site-specific risks of reoperation were calculated on the basis of 1260 intestinal resections or anastomoses performed in these patients. Young age at onset, duodenal and jejunal involvement, presence of enterocutaneous or perianal fistula, and a single surgeon (of 23) were associated significantly with increased risk of regional recurrence but not strictureplasty or inflammation at margins of resection. CONCLUSIONS: Limited surgery for Crohn's disease is not associated with increased risk of regional recurrence requiring reoperation. However, patients with juvenile onset, proximal small bowel disease, and some types of fistulae are at a considerable risk of experiencing early surgical recurrence.

Adolescent↗
PubMed1996

[The role of reperfusion damage].

Following reperfusion of preserved organ grafts, various pathomechanisms are activated that may impair graft function and viability beyond ischemic damage. This so-called reperfusion injury includes generation of oxygen radicals, recruitment and activation of circulating inflammatory cells, and liberation of numerous mediators acting both locally and systemically. Alterations in microvascular perfusion are of central importance where further graft damage is concerned. The present review covers the current knowledge about the underlying mechanisms, the organ-specific application in the clinical setting, and the possible immunological consequences of reperfusion injury.

Animals↗
PubMed1996

[Laparoscopic diagnosis and therapy of closed traumatic diaphragmatic rupture].

Diagnosis of blunt diaphragmatic rupture is still a challenging problem. This injury is generally treated by direct closure of the defect via a laparotomy or a thoracotomy. As it occurs frequently in severely traumatized patients, we wondered whether those patients could benefit from the well-known advantages of minimally invasive surgery. We report the records of two patients who underwent laparoscopy for blunt diaphragmatic hernia. In both patients, the hernia was laparoscopically closed without opening the abdomen. We did not see any intra- or postoperative complications related to minimally invasive surgery; the postoperative recovery was impressively short. Taking into account the fact that diaphragmatic ruptures are frequently misdiagnosed, we recommend laparoscopy as a useful tool in cases where these injuries may be suspected. In selected patients, primary closure of the defect may be achieved within the same laparoscopy so that laparotomy can be avoided.

Adult↗