Next generation risk assessment for skin allergy: Decision making using new approach methodologies

Our aim is to develop and apply next generation approaches to skin allergy risk assessment (SARA) that do not require new animal test data and better quantify uncertainties. Significant progress has been made in the development of New Approach Methodologies (NAMs), non-animal test methods, for assessment of skin sensitisation and there is now focus on their application to derive potency information for use in Next Generation Risk Assessment (NGRA). The SARA model utilises a Bayesian statistical approach to infer a human-relevant metric of sensitiser potency and a measure of risk associated with a given consumer exposure based upon any combination of human repeat insult patch test, local lymph node, direct peptide reactivity assay, KeratinoSens™, h-CLAT or U-SENS™ data. Here we have applied the SARA model within our weight of evidence NGRA framework for skin allergy to three case study materials in four consumer products. Highlighting how to structure the risk assessment, apply NAMs to derive a point of departure and conclude on consumer safety risk. NGRA based upon NAMs were, for these exposures, at least as protective as the historical risk assessment approaches. Through such case studies we are building our confidence in using NAMs for skin allergy risk assessment.

Association between common cardiovascular risk factors and clinical phenotype in patients with hypertrophic cardiomyopathy from the European Society of Cardiology (ESC) EurObservational Research Programme (EORP) Cardiomyopathy/Myocarditis registry

AIMS

The interaction between common cardiovascular risk factors (CVRF) and hypertrophic cardiomyopathy (HCM) is poorly studied. We sought to explore the relation between CVRF and the clinical characteristics of patients with HCM enrolled in the EURObservational Research Programme (EORP) Cardiomyopathy registry.

METHODS AND RESULTS

1739 patients with HCM were studied. The relation between hypertension (HT), diabetes (DM), body mass index (BMI), and clinical traits was analysed. Analyses were stratified according to the presence or absence of a pathogenic variant in a sarcomere gene. The prevalence of HT, DM, and obesity (Ob) was 37, 10, and 21%, respectively. HT, DM, and Ob were associated with older age (P<0.001), less family history of HCM (HT and DM P<0.001), higher New York Heart Association (NYHA) class (P<0.001), atrial fibrillation (HT and DM P<0.001; Ob p = 0.03) and LV (left ventricular) diastolic dysfunction (HT and Ob P<0.001; DM P = 0.003). Stroke was more frequent in HT (P<0.001) and mutation-positive patients with DM (P = 0.02). HT and Ob were associated with higher provocable LV outflow tract gradients (HT P<0.001, Ob P = 0.036). LV hypertrophy was more severe in Ob (P = 0.018). HT and Ob were independently associated with NYHA class (OR 1.419, P = 0.017 and OR 1.584, P = 0.004, respectively). Other associations, including a higher proportion of females in HT and of systolic dysfunction in HT and Ob, were observed only in mutation-positive patients.

CONCLUSION

Common CVRF are associated with a more severe HCM phenotype, suggesting a proactive management of CVRF should be promoted. An interaction between genotype and CVRF was observed for some traits.

Determining the effects of training duration on the behavioral expression of habitual control in humans: a multilaboratory investigation

It has been suggested that there are two distinct and parallel mechanisms for controlling instrumental behavior in mammals: goal-directed actions and habits. To gain an understanding of how these two systems interact to control behavior, it is essential to characterize the mechanisms by which the balance between these systems is influenced by experience. Studies in rodents have shown that the amount of training governs the relative expression of these two systems: Behavior is goal-directed following moderate training, but the more extensively an instrumental action is trained, the more it becomes habitual. It is less clear whether humans exhibit similar training effects on the expression of goal-directed and habitual behavior, as human studies have reported contradictory findings. To tackle these contradictory findings, we formed a consortium, where four laboratories undertook a preregistered experimental induction of habits by manipulating the amount of training. There was no statistical evidence for a main effect of the amount of training on the formation and expression of habits. However, exploratory analyses suggest a moderating effect of the affective component of stress on the impact of training over habit expression. Participants who were lower in affective stress appeared to be initially goal-directed, but became habitual with increased training, whereas participants who were high in affective stress were already habitual even after moderate training, thereby manifesting insensitivity to overtraining effects. Our findings highlight the importance of the role of moderating variables such as individual differences in stress and anxiety when studying the experimental induction of habits in humans.

Novel chimney-graft technique for preserving hypogastric flow in complex aortoiliac aneurysms

We describe the feasibility and result of a novel approach to preserve pelvic perfusion during endovascular aortoiliac aneurysm repair (EVAR) in patients with aortoiliac aneurysms extending to the iliac bifurcation. The iliac chimney-graft technique consists of the deployment of a ViaBahn™ graft into the hypogastric artery in combination with standard abdominal aortic stent-grafts. The chimney graft was deployed using a transsubclavian access and placed parallel with the iliac limb into the standard aortic stent graft, which was deployed directly before. The technical procedure was successful. Postoperative control showed a sufficiently excluded aneurysm without evidence of endoleak and good distal perfusion of both iliac arteries. The CT-scan after 6 months confirmed the result. The chimney-graft stent grafts to maintain perfusion to hypogastric arteries are feasible and provide an alternative to hypogastric artery exclusion or branched grafts. Long-term follow-up is needed to evaluate stent-graft patency and failure rates.

Outcome of carotid endarterectomy under local anaesthesia with respect to the patients' risk profile

BACKGROUND

In the present study the perioperative complication rate is compared between high- and low-risk patients when carotid endarterectomy (CEA) is routinely performed under local anaesthesia (LA).

PATIENTS AND METHODS

From January 2000 through June 2008 1220 consecutive patients underwent CEA under LA. High-risk patients fulfilled at least one of the following characteristics: ASA 4 classification, "hostile neck", recurrent ICA stenosis, contralateral ICA occlusion, age > or = 80 years. The combined complication rate comprised any new neurological deficit (TIA or stroke), myocardial infarction or death within 30 days after CEA, which was compared between patient groups.

RESULTS

Overall 309 patients (25%) were attributed to the high-risk group, which differed significantly regarding sex distribution (more males: 70% vs. 63%, p = 0.011), neurological presentation (more asymptomatic: 72% vs. 62%, p = 0.001) and shunt necessity (33% vs. 14%, p < 0.001). In 32 patients 17 TIAs and 15 strokes were observed. In 3 patients a myocardial infarction occurred. Death occurred in one patient following a stroke and in another patient following myocardial infarction, leading to a combined complication rate of 2.9% (35/1220). In the multivariate analysis only previous neurological symptomatology (OR 2.85, 95% CI 1.38-5.91) and intraoperative shunting (OR 5.57, 95% CI 2.69-11.55) were identified as independent risk factors for an increased combined complication rate.

CONCLUSIONS

With the routine use of LA, CEA was not associated with worse outcome in high-risk patients. Considering the data reported in the literature, it does not appear justified to refer high-risk patients principally to carotid angioplasty and stenting (CAS) when LA can be chosen to perform CEA.

Signalling processes involved in C-peptide-induced chemotaxis of CD4-positive lymphocytes

Previous data from our group demonstrated that C-peptide induces chemotaxis of CD4-positive lymphocytes in-vitro, mediated by activation of G-protein and PI 3-kinase gamma, but additional signalling pathways involved in this process remained unexplored. In the present study we further analyze intracellular signalling pathways which lead to C-peptide-induced CD4-positive lymphocyte migration. We provide evidence that C-peptide-induced chemotaxis of CD4-positive lymphocytes is critically dependent on activation of Src-kinase and RhoA, Rac-1 and Cdc42 GTPases. Furthermore, C-peptide stimulates phosphorylation of PAK, LIMK and cofilin downstream of Rac-1 and Cdc42, leading to cofilin inactivation and actin filament stabilization. In addition, C-peptide induces ROCK kinase activity and MLC phosphorylation downstream of RhoA, thereby stimulating myosin mediated cell contraction. In contrast, C-peptide does not activate ERK1/2, p38 or Akt in CD4-positive lymphocytes. Our data support an active role of C-peptide in CD4-positive lymphocyte chemotaxis and elucidate molecular mechanisms in C-peptide-induced cell migration.

[The role of intra-operative Prostavasin application during crural bypass surgery]

INTRODUCTION

The aim of this study was to evaluate the role of intra-operative Prostavasin application during crural bypass surgery. 68 Patients, who underwent infrainguinal autologous vein bypass surgery, were prospectively analyzed.

RESULTS

Intra-operative flow measurements and Prostavasin administration were performed in all patients. The mean flow was 105 ml / min (minimal flow 18 ml / min, maximal flow 321 ml / min). The means of maximal and minimal flow were 329 und 30 ml / min, respectively. The mean of the calculated Pulsatility index was 3.1. The mean flow volume increased after administration of Prostavasin in all patients with a mean increase of 103 %. The Pulsatility index decreased by 39 %. Primary and secondary patency rates after 1 year were 70.3 % und 73.1 %, respectively. The differentiated analyses of the region of the distal anastomoses (popliteal / crural) showed a statistically significant bigger increase of Q after Prostavasin application for infrainguinal popliteal bypasses compared to patients with crural reconstructions (p = 0.05). In addition, the decrease of the Pulsatility index was significantly higher in popliteal grafts (p = 0.03). Patients with early bypass graft failure showed a significantly smaller decrease of PI after Prostavasin application compared to the other patients.

CONCLUSION

The profit of intra-operative arterial Prostavasin application is first of all an immediate one. The injection of Prostavasin leads to an instant vessel dilatation. This allows the surgeon to get an impression of the flow capacity of the bypass. The Pulsatility index as an indicator for resistance is an important factor for bypass patency.

Evaluation of Changes of Systemic Blood Pressure and Shunt Incidence in CEA

BACKGROUND

Induced hypertension is widely recommended as a protective measure in carotid endarterectomy (CEA) to prevent shunt insertion. In this study changes of systemic blood pressure were evaluated in relation to the shunt rate when CEA was performed under local anaesthesia.

MATERIALS AND METHODS

In 930 CEAs performed for a high-grade (>70%) ICA stenosis under local anaesthesia the mean systemic blood pressure was measured preoperatively (RR1) and directly before carotid cross-clamping (RR2). A ratio was calculated from these values (RRR=RR2/RR1). A shunt was only inserted for clinical signs of cerebral ischemia. If that became necessary later after cross-clamping had been tolerated primarily, the blood pressure during this period was also recorded (RR3). Also the presence of a contralateral ICA occlusion and baseline blood pressure levels were considered as factors with potential impact on shunt necessity.

RESULTS

Among the 638 male (69%) and 292 female (31%) patients with a median age of 70 years (ranging from 52 to 91 years) 82 (9%) had a contralateral ICA occlusion. A shunt was used in 177 operations (19%) and significantly more frequent in patients with a contralateral ICA occlusion (39/82=48% vs. 138/848=16%, p<0,001). RRR was significantly reduced in patients who needed a shunt (0.95 (0.41-1.53) vs. 1.0 (0.54-1.9), p=0.002) which was only true for patients with a patent contralateral ICA. The shunt rate did not differ when contrasting RRR thresholds (<0.7 vs. >1.3) or preoperative blood pressure levels (<100 mmHg vs. >120 mmHg) were compared. RRR did not differ between directly or delayed shunted patients. RR3 did not differ significantly from RR2. A regression analysis identified the presence of a contralateral ICA occlusion as the only independent parameter influencing shunt insertion.

CONCLUSIONS

Changes in systemic blood pressure during CEA under local anaesthesia seem to influence shunting rather marginally. The value of induced hypertension to prevent cerebral ischemia should be newly discussed.

Meta-analysis of Randomized Trials Comparing Carotid Endarterectomy and Endovascular Treatment

OBJECTIVE AND DESIGN

In order to evaluate the comparative efficacy and safety of carotid angioplasty with or without stent placement (CAS) versus carotid endarterectomy (CEA) we performed a meta-analysis of the presently available randomized studies.

MATERIALS AND METHODS

A multiple electronic health database search on all randomized trials describing CAS compared with CEA in patients with symptomatic or asymptomatic carotid artery stenosis was performed.

RESULTS

Seven trials totalling 2972 patients (1480 randomized to CEA and 1492 randomized to CAS) were included in the meta-analysis. Results significantly favoured CEA over CAS in terms of death or any stroke at 30 days after procedure; the risk of death, any stroke, or myocardial infarction at 30 days; ipsilateral ischaemic stroke at 30 days; any stroke at 30 days; death or stroke at 6 months; and the risk of procedural failure. There was a significantly reduced risk of cranial neuropathy at 30 days after CAS. There was no significant difference between CAS and CEA groups in the odds of death or disabling stroke at 30 days, death or stroke at 1 year after the procedure, and ipsilateral intracerebral bleeding at 30 days.

CONCLUSIONS

The results of this meta-analysis suggest that CEA can be performed with more safety than CAS. As a result, CEA remains the "gold standard" treatment for suitable de novo carotid stenosis and CAS should only be performed within randomized trials of stenting versus surgery.

Endovascular treatment of a ruptured aneurysm of the inferior thyroid artery. Case report and literature review

Aneurysms of the inferior thyroid artery are rare. The natural course of these aneurysms seems to be unfavourable, why aneurysm exclusion is recommended in the literature. Open surgical repair is complex why endovascular exclusion seems to be an appealing alternative. We present a patient who developed dysphagia and respiratory distress caused by a ruptured aneurysm of the right inferior thyroid artery. Successful coil embolization of the aneurysm is described along with a review of the literature. Despite the very rare data of these aneurysms, all reported cases of endovascular treatment (n=3) showed favourable results, therefore aneurysm embolization seems to be a feasible and safe alternative to open surgery, especially in emergency cases.

Hybrid-procedures for the Treatment of Thoracoabdominal Aortic Aneurysms and Dissections

AIM

The conventional open repair of thoracoabdominal aneurysms and dissections remains complex and demanding and is associated with significant morbidity and mortality. We present our experience of hybrid open and endovascular treatment of thoracoabdominal aneurysms and dissections.

METHODS

Within an experience of 226 aortic stent-grafts between 1998 and April 2006, 6 of the patients (median age 60 years, range 35 to 68 years) with thoracoabdominal aneurysms (Crawford type I, II, III, and V) were treated with a combined endovascular and open surgical approach. Five men and one woman, with median aneurysm diameter of 75 mm (range 70-100 mm), received revascularization of the renal arteries, the superior mesenteric artery, and the coeliac trunk accomplished via transperitoneal bypass grafting. Aneurysmal exclusion was then performed by stent-graft deployment.

RESULTS

The entire procedure was technically successful in all patients. The patients were discharged a median of 9 days after the operation, while the postoperative studies revealed the patency of the vessels and no evidence of type I endoleak or secondary rupture of the aneurysm. During follow up (1 to 22 months) spiral-CT scanning revealed distinct shrinkage of the aneurysm, no graft migration or endoleak and patency of all revascularised vessels, except one renal artery in two patients. No patient experienced any temporary or permanent neurological deficit, and no dialysis was necessary.

CONCLUSION

The combined endovascular and open surgical approach is feasible, without cross clamping of the aorta and with minimized ischemia time for renal and visceral arteries, and seems to be an appropriate strategy for patients with a thoraco-abdominal aortic aneurysm or dissection.

Primary Stroke Unit Treatment Followed by Very Early Carotid Endarterectomy for Carotid Artery Stenosis after Acute Stroke

BACKGROUND

Although it is recognized that carotid endarterectomy (CEA) is the treatment of choice in symptomatic internal carotid artery (ICA) stenosis, in the past, very early CEA has been shown to carry substantial risks. We assessed an interdisciplinary concept of very early CEA in patients with high-grade (>70%) symptomatic ICA stenosis at a single center.

PATIENTS AND METHODS

The course of treatment and outcomes of patients who underwent CEA as early as possible after being referred to the stroke unit for symptoms of transient ischemic attack and stroke were prospectively evaluated, including the following parameters: age, severity of ischemia-related symptoms according to the modified Rankin scale, duration of symptoms until admission, multimodal imaging findings (color-coded duplex, cranial computed tomography, magnetic resonance imaging, positron emission tomography), duration until CEA, perioperative course and complications, as well as duration of in-hospital care.

RESULTS

Fifty consecutive patients (median age 68 years, range 44-90) with clinical and imaging signs of transient ischemic attack (n = 19) or stroke (n = 31) were included from January 2000 until December 2004. All except 1 patient showed a preoperative Rankin < 4. There was a median time period of 6 h between the onset of symptoms and admission (range 1 h to 15 days) and a median duration of 4 days after admission until operation (range 1-21 days). Seven patients underwent CEA of the contralateral, severely stenosed ICA after symptomatic ipsilateral ICA occlusion. Four out of 5 patients who primarily underwent systemic thrombolysis recovered almost completely. Three patients (6%) experienced a clinical deterioration before surgery. In the majority of patients (43/50), CEA was performed under local anesthesia with selective shunt use which became necessary in 26%. Three patients (6%) had postoperative worsening due to new infarcts. In 2 cases, an intracerebral hemorrhage occurred, of which 1 remained asymptomatic. In 1 case, surgical revision was necessary because of an ICA thrombosis without permanent neurological decline. Patients were discharged after a median time of 14.5 days (range 4-44).

CONCLUSIONS

After careful selection and preparation in a stroke unit, patients with acute stroke due to carotid stenosis can undergo very early CEA under local anesthesia with a perioperative risk comparable with the risk of later endarterectomy, therefore preventing very early stroke recurrences.

Cognitive Function Remains Unchanged After Endarterectomy of Unilateral Internal Carotid Artery Stenosis Under Local Anaesthesia

OBJECTIVE

To assess changes in cognitive function and affective state following carotid endarterectomy (CEA) for high-degree unilateral internal carotid artery stenosis.

METHODS

In 33 patients, a CEA was performed under local anaesthesia for a high-grade unilateral stenosis of the internal carotid artery (group A). Twenty-five patients underwent surgery for peripheral arterial occlusive disease under regional anaesthesia served as controls (group B). Patients with neurological deficits due to previous strokes or dementia were excluded. Intelligence level was assessed preoperatively. Cognitive tests were applied preoperatively and postoperatively (3-5 days after surgery) and after 4 months follow-up. Confounding factors, including anxiety and depression, were checked through questionnaires and interviews.

RESULTS

No perioperative neurological complication occurred following CEA. Patients in group A showed a significant postoperative deterioration only in one sub-test. There was no significant change in anxiety and depression during follow up. The control group B had no significant changes in cognitive test performance. Anxiety improved significantly postoperatively, but increased again at the end of the study. There was no significant difference between the groups over time.

CONCLUSION

Cognitive function does not change following CEA of a unilateral internal carotid stenosis.

Changes in internal carotid blood flow after CEA evaluated by transit-time flowmeter

AIM

The aim of this study was to investigate whether there was an association between the degree of the stenosis of the internal carotid artery (ICA) and post-operative increase of blood flow.

METHODS AND MATERIALS

In 200 out of 660 patients undergoing carotid endarteriectomy (CEA) for a high-degree ICA stenosis, pre-operatively a bilateral selective carotid and intracerebral angiography was performed. The degree of the ipsilateral and contralateral stenosis was digitally assessed by using computer software according to the CC-Index. Intraoperatively, the pressure ratio over the stenosis (ICA/CCA) was measured by direct arterial puncture. Blood flow in the ICA was measured before and after CEA with an ultrasound flowmeter using the transit-time principle. These findings were correlated to the degree of stenosis revealed by angiographic analysis and the pressure ratio.

RESULTS

Before CEA the median blood flow in the ICA was 171 ml/min (range 620 ml/min) with a significant (p<0.001) post-operative increase to 250 ml/min (range 875 ml/min). The median relative increase of flow (post-flow-pre-flow/pre-flow) was 42%. The pre-CEA flow volumes were dependent on the degree of stenosis and also the pressure ratio. The increase of flow following CEA correlated better with pressure ratio (r=-0.435, p<0.001), than the stenosis severity (r=0.319, p<0.001). Analysis of variance identified only the pressure gradient as an independent determinant of flow changes following CEA.

CONCLUSIONS

The blood flow increase following CEA is mainly determined by the pressure gradient across the stenosis.

Comparison of the Prevalence of APC-resistance in Vascular Patients and in a Normal Population Cohort in Western Germany

OBJECTIVE

To compare the prevalence of APC-resistance (APC-R) in patients with peripheral vascular disease and the general population.

DESIGN

Prospective cohort examination.

MATERIALS AND METHODS

Three hundred and eleven patients (group A) suffering from arterial occlusive disease or an abdominal aortic aneurysm were prospectively screened for APC-R. There were 228 men and 83 women with a mean age of 65 years (20-88 years). Two hundred and sixty patients underwent an open surgical or interventional procedure. A total of 306 patients were followed clinically for an average of 8 months (1-31 months). Two hundred and seven healthy volunteers (group B) served as a control group.

RESULTS

The prevalence of a functional APC-R was 11% (33/311) and 8% in groups A and B, respectively, (p = 0.272). APC-R did not occur more frequently among patients who were treated primarily for a bypass occlusion (3/21 vs 30/290) (p = 0.476). None of five patients who had a postinterventional graft or vessel occlusion (1.9%) had an APC-R. Sixteen patients (5%) experienced an arterial occlusion during follow-up of which two had APC-R.

CONCLUSIONS

Previously published increased prevalence rates of APC-R in patients with arterial disorders could not be confirmed in this study. A firm association between the presence of APC-R and previous bypass occlusion or postoperative failure of the vascular reconstruction could not be demonstrated.

Radiation therapy induced modulation of wound healing at experimental vein graft anastomoses

OBJECTIVES

The aim of this study was to investigate if radiation therapy (RT) favorably modulates wound healing at vein graft anastomoses.

MATERIALS AND METHODS

Jugular vein grafts were sewn into carotid arteries in 32 rats which were randomly divided into two groups: RT (gamma source, 14 Gray, n=16) and control (C, sham irradiation, n=16). Grafts and adjacent arteries were analyzed at 2 (n=8) and 8 weeks (n=8) by histology, immunohistochemistry, and morphometry.

RESULTS

Although, RT did not reduce the overall occurrence of intimal hyperplasia, the distribution differed. RT led to a reduction of intimal hyperplasia in arterial segments (median: C: 41.873 microm2; RT: 6.452 microm2, p < 0.0007). In contrast, RT augmented intimal hyperplasia in vein grafts (median: C: 30.287 microm2; RT: 90.455 microm2, p < 0.014). Vein graft diameters after RT were enlarged (median: C: 2.098 microm; RT: 3.381, p < 0.031). Over 80% of the cells were of mesenchymal origin in both groups.

CONCLUSIONS

RT reduced intimal hyperplasia in arterial segments. However, RT led to graft dilatation and increased intimal hyperplasia in vein grafts. RT did not favorably modulate the vascular wound healing response in this model.

Differentiated treatment of aneurysms of the extracranial carotid artery

AIM

Aim of the study is to illustrate current therapeutic options for aneurysms of the extracranial carotid artery.

METHODS

From 1987 until 2003 14 patients (average age: 60 years) with an aneurysm of the extracranial internal carotid artery were treated. The aneurysm diameter ranged from 5 mm to 60 mm. Thirteen patients underwent elective surgery. One patient was operated upon because of acute severe cervical bleeding.

RESULTS

Most patients (10/14) presented with an asymptomatic pulsatile cervical mass. The aneurysm was diagnosed 3 times during carotid angiography. The underlying etiology was atherosclerosis in 10 patients. In 3 cases the aneurysm was considered mycotic. Ten aneurysms were localized at the carotid bifurcation whereas 2 each were found in the retrostyloideal region and at the base of the skull. Vascular continuity could be restored in 10 patients while in 3 the carotid artery had to be occluded (twice surgically and once radiologically). The final patient underwent stent insertion for post-traumatic distal aneurysm. In 5 patients perioperative neurological complications were noted which persisted in a single patient (dysphagia due to a lesion of the hypoglossus nerve). All hemispheric complications recovered completely. During follow-up (median 48 months ranging from 3 to 103 months), 1 patient died of unrelated cause. Another patient developed a contralateral ischemic insult.

CONCLUSIONS

When adjusting treatment to the various etiological conditions and localizations, aneurysms of the extracranial carotid artery can be managed with a low complication rate and satisfying long-term results. However, success mainly depends on the timely diagnosis and availability of a range of surgical and radiological therapeutical options.

Pulsatility Index Determination by Flowmeter Measurement: A New Indicator for Vascular Resistance?

BACKGROUND

Peripheral resistance (R) is measured by flow (Q) and a pressure difference (P1-P2), where R equals (P1-P2)/Q. The pulsatility index (PI) has been used to assess peripheral vascular resistance by measuring flow velocities. Alternatively, PI can be expressed by the ratio of the flow volume amplitude and mean flow volume which both are quantified by a flowmeter. While reflected flow due to a distally located stenosis will considerably influence PI, this parameter theoretically could provide a good estimation of resistance. The appropriateness of this presumption has not been evaluated in this setting though, why the correlation of PI in flow recordings was examined by comparing PI with the true R using the stenosis of the internal carotid artery (ICA) as a clinical model.

METHODS

The volume flow in the ICA was measured by a transit-time flowmeter in 400 patients undergoing carotid endarteriectomy. The pressure in the common carotid artery (CCA) proximal to and in the ICA distal to the stenosis was determined by direct puncture allowing the calculation of a pressure gradient (PG) and R in analogy to Ohm's law. R and PI were then correlated using Spearman's correlation.

RESULTS

The blood flow in the ICA ranged from 2 to 478 ml/min with a median value of 165. The median PG was 14 mm Hg (0 to 88). Median R was 0.08 mm Hg x min / ml (0-26.5). PI varied between 0.8 and 114.1 with a mean of 1.9. Since a concentration of R and PI values in the lower ranges was observed, a logarithmic transformation was performed. Log PI showed only weak correlation to log R (r = 0.426, p < 0.0001).

CONCLUSIONS

Log PI was intermediately correlated to log R in carotid artery stenosis, with a low discriminating power in the lower ranges due to the close distribution of measurements. Further studies are required to clarify the role of PI in hemodynamic questions and its general usefulness in other fields of vascular surgery like in peripheral bypass surgery.

Modulation of Human Adventitial Fibroblast Function by Photodynamic Therapy of Collagen Matrix

OBJECTIVES

Photodynamic therapy (PDT) is a promising strategy to limit restenosis. PDT depletes the resident cells from the vessel wall without adventitial cell ingrowth. This study was undertaken to further explore the mechanisms by which PDT of matrix acts on key mechanisms in the development of restenosis.

MATERIALS AND METHODS

Control and PDT-treated collagen type-I matrix gels were prepared. Thereafter, untreated human fibroblasts were seeded on matrix gels (n=12). Fibroblast proliferation and invasive migration were quantified by calibrated phase contrast microscopy. Fibroblast bFGF and TGF-beta1 mRNA expression were analyzed using a quantitative real-time reverse transcription polymerase chain reaction.

RESULTS

Fibroblast proliferation on PDT-treated matrix gels was reduced by 30 and 76% after 3 and 7 days, respectively (3 days: P</=0.01, 7 days: P< or =0.001). PDT of matrix gels led to a 47% reduction of migration after 3 days and 51% after 7 days (P< or =0.001). PDT led to a 77% reduction of fibroblast TGF-beta1 mRNA (P< or =0.02) and to a 79% reduction of bFGF mRNA (P< or =0.03).

CONCLUSIONS

PDT of matrix-induced reduction of bFGF and TGF-beta1 mRNA levels may be important mechanisms of reducing fibroblast proliferation and invasive migration and thus the development of restenosis. These newly identified mechanisms highlight PDT's pleiotropic effects on the vessel wall and its potential clinical value.

Prediction of Cerebral Ischemic Tolerance During Carotid Cross-clamping by Angiographic Criteria

OBJECTIVE

To evaluate the prognostic value of angiographic criteria and internal carotid artery (ICA) stump pressure for shunt placement in carotid surgery under local anaesthesia.

DESIGN

Prospective clinical trial at a university hospital.

MATERIALS AND METHODS

In 120 patients a cerebral angiography was initiated before undergoing carotid surgery. Seventy-five percent of the patients were neurologically asymptomatic, 13% had transient ischaemic attacks and 12% suffered from previous strokes. The operation was exclusively performed under local anaesthesia and prior to cross-clamping the ICA stump-pressure was measured. A shunt was inserted only if hemispheric symptoms or unconsciousness occurred independent of the angiographic findings or stump pressure.

RESULTS

In 23% (27/120) a shunt became necessary and significantly (p<0.001) more often when there was a cross-flow towards the contralateral hemisphere (12/20=60%) or if the contralateral ICA was occluded (9/13=69%). The sensitivity for not needing a shunt in case of cross-flow towards the side of operation was 91% (52/57) whereas the specificity was 35% (22/63). ICA stump-pressure was significantly reduced in patients requiring a shunt (31 mmHg) compared to those not needing a shunt (53 mmHg) (p<0.001), but no definitive threshold value was found determining the need for shunting. Intraoperatively, no persistent neurological complication developed.

CONCLUSIONS

Angiographic cross-flow was a good, but not perfect predictor for the need of an intraoperative shunt.

Surgical approach to kinking and coiling of the internal carotid artery

AIM

Whether kinking or coiling of the internal carotid artery (ICA) simply represents a morphological variation without clinical relevance still remains an object of debate. While most patients are incidentally diagnosed in an asymptomatic state due to the broad use of non-invasive investigations (like colour coded Doppler sonography), associated neurological deficits are often unspecific and might be related to coexisting proximal stenotic lesions. Its etiology is unclear. Beside artherosclerotic genesis, a persistent embryological condition or underlying fibromuscular dysplasia is discussed. Moreover, in contrast to precise recommendations concerning the indication for endarteriectomy in carotid artery stenosis, general guidelines for surgical intervention in case of kinking or coiling are not yet established.

METHODS

The characteristics of 16 patients who underwent a total of 21 reconstructive operations for isolated kinking or coiling of the ICA during 5 years of observation were retrospectively analyzed.

RESULTS

In 10 out of 14 kinkings and 5 out of 7 coilings central nervous symptoms were noted including unspecific vertigo, syncope, tinnitus synchronous to pulse, transient ischemic attacks and manifest cerebral infarction. All these individual complaints disappeared postoperatively. In 1 patient presenting with an ICA coiling histological examination revealed signs of fibromuscular dysplasia. The other specimens showed typical changes of artherosclerotic disease.

CONCLUSION

By precluding significant proximal stenosis and effective elimination of symptoms after surgical correction, a causal connection between cerebral dysfunction and severe ICA kinking or coiling can be supposed. An actual abnormality of the arterial wall structure only exists in exceptional cases. Rather, a sequential development from kinking to coiling was noticed.

HPLC assay of acetylsalicylic acid, paracetamol, caffeine and phenobarbital in tablets

This paper present a HPLC method for simultaneous determination of acetylsalicylic acid, paracetamol, caffeine and phenobarbital in tablets, using chromatographic system consisting a Bio Rad 18 01 solvent pump, Rheodine 71 25 injector and Bio Rad 18 01 UV-Vis Detector. Separation was achieved using Bio SiL HL C18, 5 microm, 250 x 4.6 mm column. Mixture of acetonitrile-water (25:75 v/v) adjusted to pH 2.5 with phosphoric acid was used as a mobile phase at a flow rate of 2.0 ml min(-1). UV detection was at 207 nm range 0.01 AUFS. Under the same conditions it was possible to determine the level of salicylic acid. The chromatographic parameters such as retention times, capacity factor, peak asymmetry, selectivity factor and resolution factor was determined. The validation parameters: linearity (r > 0.998), intra-day precision (RSD: 0.36-1.89%) and inter-day precision (RSD: 0.58-2.18%), sensitivity (LOD: 9 x 10(-5)-1.7 x 10(-4) mg ml(-1) and LOQ: 2.5 x 10(-4)-5.6 x 10(-4) mg ml(-1)), accuracy (recoveries: 98.35-99.14%) and reproducibility (recovery values: 98.74-102.08% for acetylsalicylic acid, 99.93-102.11% for paracetamol, 98.25-102.12% for caffeine and 98.15-102.3% for phenobarbital) (RSD: 1.21-1.85%) were found to be satisfactory. The proposed HPLC method has been applied for the determination of acetylsalicylic acid, paracetamol, caffeine and phenobarbital in Malophenum tablets. The obtained RSD values were within 0.99-1.21%. The developed method is rapid and sensitive and therefore suitable for routine control of these drugs in dosage form.

Surgical treatment of non-ampullary duodenal cancer: good long term survival after radical tumour resection including lymphadenectomy

AIMS

The aim of this study is to evaluate the role of surgery in the treatment of duodenal cancer.

METHODS

From October 1987 to January 1999, 7 patients (3 female/4 male) with primary non-ampullary duodenal adenocarcinoma underwent surgical treatment in our department. Presenting signs and symptoms were abdominal pain, weight loss, anaemia and obstruction. Upper gastrointestinal contrast study, computed tomography (CT) and duodenoscopy were the primary diagnostic procedure modalities. All diagnoses were confirmed histologically. Five of 7 patients were resectable for cure at the time of their first surgical intervention.

RESULTS

In 5 patients, the tumour could be removed with tumour-free margins. One patient, where the histopathological workup revealed tumour cells in the resection margins, died 29 months after the surgical intervention. In another patient, complete tumour resection could not be achieved. Subsequently, postoperative survival was only 2 months. Operative mortality was 0%. Patients with R0-status showed a postoperative survival of at least 24 months.

CONCLUSION

In the management of resectable non-ampullary malignancies of the duodenum, surgical radicality including lymphadenectomy should be pursued. The radical operative treatment with lymphadenectomy offers a reasonable chance for cure in some patients.

Surgical treatment of locally advanced rectal cancer. Options and strategies

AIMS

The results of surgical treatment of locally advanced rectal cancer with special regard to multivisceral resections and preoperative radiotherapy should be analyzed.

METHODS

From 10/86 until 12/95, 40 patients with preoperatively assessed T4 stage rectal cancer were treated in our department whose data were evaluated retrospectively.

RESULTS

Apart from 10 nonresecting procedures we performed 30 resections in which the mortality rate was 7%. In 50% of these patients a multivisceral resection was conducted. A R0 situation could be achieved in 70%. But only in 53% the operation was carried out with curative approach due to distant metastasis. After extended resections more frequent urological complications resulted in prolonged hospitalization. Survival time was markedly longer in patients without tumor residuals or metastasis. Following preoperative radiotherapy a higher number in tumor free patients and better prognosis was noticed.

CONCLUSIONS

In accordance to the literature it is suggested to submit patients with T4-stage rectal cancer to preoperative radiation to improve the overall outcome.

Electrochemical study of cefetamet-Na and its polarographic determination

Polarographic behavior of cephalosporin cefetamet-Na (Cef-Na) in aqueous solutions of pH ranging from 1.7 to 12.5 was investigated by applying direct current (dc) polarography, differential pulse polarography (dpp), alternating current (ac) polarography, cyclic voltammetry and electrolysis at constant potential. The characteristics of the corresponding electrode reaction are presented and discussed. The electrode reaction was found to be affected by strong adsorption, strongly and slightly pronounced in acidic and alkaline media, respectively. The methoxyimino group electroreduction was carried out and the mechanistic scheme was suggested. In addition, a sensitive dpp method was proposed for analytical determination of a very low concentrations of Cef-Na.

Rectal cancer surgery in a district general hospital: controlled follow-up study

Local recurrence after curative surgery of rectal cancer indicates failure of the initial treatment. In recent years reported local recurrence rates have steadily decreased. In this study 364 patients treated for rectal cancer were analyzed retrospectively to determine if it is still justified to treat this disease in small nonspecialized hospitals. An overall local recurrence rate of 9.7% was found for all operation methods used. Local recurrence rates were 11.6% for patients treated by low anterior resection, 8.4% for the patients who sustained an amputation of the rectum, and 7.1% for the patients treated by transanal tumor resection. None of the patients in whom we performed a total mesorectal excision has developed local recurrent disease during the observation period. Careful surgical technique and close follow-up of the patients being prerequisites, the results of this study justify continuing to treat rectal cancer in nonspecialized centers.

[Urologic reconstruction within the scope of interdisciplinary pelvic exenteration for treatment of invasive tumors of the pelvis]

In radical surgical treatment of primary or recurrent locally advanced pelvic carcinoma involving the bladder, urinary diversion after cystectomy significantly increases the overall morbidity rate. Analyzing 20 patients retrospectively who underwent total pelvic exenteration from 1988-1997, we found that reconstruction by ileal conduit can be performed safely but leaves the patient with a (mostly second) stoma. The advantage of continence with pouch or neobladder reconstruction needs to be weighed up in view of the more demanding and complicating surgical technique, hence it should be reserved for younger, cooperative patients presenting with a favorable long term prognosis.

[Significance of CT in the detection of regional lymph node metastases in colorectal carcinoma]

PURPOSE

For preoperative staging of colorectal cancer a CT scan is frequently performed. This report examines the sensitivity of CT for regional lymph node metastasis of colorectal cancer using different criteria.

MATERIALS AND METHODS

Preoperative CT scans of 153 patients with colorectal cancer were analyzed using different criteria for N1. The results were then compared to the postoperative histological findings.

RESULTS

For N1 = lymph nodes (LN) > 1 cm the sensitivity was 47%. For N1 = LN > 1 cm or an increased number of LN < 1 cm the sensitivity was 71%. In patients with a primary tumor seen on CT, sensitivity rose to 87%.

DISCUSSION

Evidence of regional nodal metastatic disease is only relevant for rectal cancer, colon polyps, and for locally excised tumors when considering present surgical concepts for the treatment of colorectal cancer. In these cases CT analysis using the broadened criteria for N1 proposes a valuable argument regarding possible preoperative radiotherapy or an operative revision.

[Indications and follow-up of total pelvic exenteration]

From 1988 to 1996 we performed 18 total pelvic exenterations in patients with an average age of 59.8 years who could be followed up for a mean 29.8 months. In 10 cases a recurrent tumor of the pelvic viscera and 7 times a primary carcinoma of the rectum, bladder or prostate were treated. In 1 patient a radiogenic fistula led to this operation. Intestinal continuity could be reconstructed in 7 cases. Following cystectomy, urinary diversion was accomplished in half of the cases by an ileal conduit. Due to septic multiorgan failure 2 patients died postoperatively (hospital mortality rate 11%). In 82% a complete resection (R0) was possible. Subsequently 5 patients (29%) developed tumor recurrence. Distant metastases were observed in 3 patients, 8-9 months after surgery. So far 10 further patients have died. Their mean survival time was 28.9 months (range 5-99 months). The remaining 6 patients are still alive between 22 and 36 months postoperatively. Despite the extent of this kind of major surgery, which also requires multidisciplinary cooperation, and the psychosocial problems resulting from two permanent stomas, total pelvic exenteration should be regarded as an adequate alternative in the treatment plan in selected patients with locally advanced or recurrent pelvic disease.

[Problems in diagnosis and surgical therapy of choledochus cysts. A case report]

We report a case of choledochal cyst accompanied by an adenoid gallbladder carcinoma, in an adult patient. Diagnosis was complicated by coexisting primary hyperparathyroidism. In view of the pathological laboratory tests, which suggested acute pancreatitis, the visualized cystic abdominal mass was regarded as a pancreatic pseudocyst. Neither ultrasound nor CT could clearly define the cyst's origin. Laparotomy, performed later because of deteriorating clinical condition, showed an extended carcinoma which was already invading the liver. Only palliative resection and choledochocystojejunostomy was technically feasible. To prevent the development of malignancies in dilated bile ducts, early treatment by cyst resection and reconstruction of the extrahepatic biliary system is recommended, especially in younger patients.

[Results of surgical therapy of esophageal carcinoma in a general hospital]

From January 1987 until December 1994 103 patients were treated for esophageal cancer in our department. Operability was 77.7%, 75.7% were resected. Postoperative lethality was 9.0% within 30 days and 16.7% for the whole hospital stay. Concerning the resected patients 37.5% adenocarcinoma and 60.0% squamous cell carcinoma were found. The most common localisation of the tumor was the lower third of the esophagus (62.5%). 35.9% underwent an abdominothoracic resection whereas in 64.1% a transhiatal esophagectomy was carried out. The UICC-stage distribution was as follows: I 11.3%, IIa 10.0%, IIb 12.5%, III 40.0%, IV 26.3%. In 79.2% of the cases lymph node metastasis were already recognizable. The median survival time was 10 (3-72) months with better outcome for adenocarcinoma, lymph node negative patients and early tumor stages. Even if only palliation was the aim of the surgical procedure esophagectomy followed by collar esophagogastrostomy provides satisfying results to regain the ability to swallow.

A comparison of cytology and cervicography in cervical screening

The sensitivity and specificity of cervical cytology and of cervicography in the detection of CIN and invasive cancer of the cervix were determined in a screening programme of an asymptomatic population of 418 women. Because all of the subjects were examined colposcopically and biopsies were taken from any suspicious areas, the presence or absence of disease was determined by the histology of directed cervical biopsies independently of the screening methods being tested. Cervicography correctly identified 24 of the 27 women with CIN or invasive cancer, whereas cytology detected only 14 (sensitivity of 0.89 vs. 0.52; P < 0.01). Cervicography detected CIN in 11 women with negative smears, six having CIN III. Only one case of CIN I was detected by cytology when cervicography was negative. Two cases of CIN II were not detected by either method. Inclusion in the analysis of the results from 23 women with technically defective cervigrams reduced the size of the difference in sensitivity, but it remained significant (0.74 vs. 0.48; P < 0.05). Cervicography was only slightly less specific than cytology (0.92 vs. 0.94; NS). Cervicography appears to be more effective than cytology in screening for cervical premalignancy but may be more demanding of those who perform the test.

[Occult splenic rupture difficult to diagnosis]

The recognition of an occult rupture of the spleen is very difficult if there is no anamnesis of a trauma. Computer-tomographically the diagnosis can be made quickly and convincingly. An own case demonstrates the superiority of computer-tomography to conventional radiologic and ultrasonic methods.