Biomedical subjects

B Klosterhalfen

Publications and source records attributed to B Klosterhalfen.

At least 37 records · Page 2Linked to original sources

PubMed2001

Bax expression in benign and malignant thyroid tumours: dysregulation of wild-type P53 is associated with a high Bax and P21 expression in thyroid carcinoma.

The purpose of our study was to determine the expression of the pro-apoptotic BAX protein in relation to the mutational status of BAX and p53 (as transcriptional activator of the BAX gene) in benign and malignant thyroid tissue. In 47 patients with thyroid tumours (14 follicular and 3 papillary carcinomas, 14 adenomas and 16 goitres), the DNA was screened for mutations of BAX (exon 1-6) and p53 (exon 5-8) by single-strand conformation polymorphism polymerase chain reaction (SSCP-PCR). Furthermore, the protein expression of BAX, p53 and p21 (which is also increased transcriptionally by p53) was investigated by immunohistochemistry. Surprisingly, we observed elevated BAX levels in patients with thyroid carcinomas compared with patients with adenomas (unpaired t-test: p<0.05) or with goitres (p<0.02). This is in clear contrast to other carcinomas where BAX is frequently inactivated which correlates to a poor prognosis (Sturm et al. J. Clin. Oncol. 1999;17:1364-74.). There were no significant differences of the BAX levels between goitres or the adenomas. In the SSCP-PCR analysis, no BAX mutations were detectable. P53 mutation analysis by SSCP-PCR did not reveal any functional p53 mutations in the patients with carcinomas, adenomas or goitres. Nevertheless, patients with carcinomas showed an overexpression (preferentially cytoplasmic) of p53 protein compared with patients with benign tumours (p<0.05). The absence of p53 mutations suggests that the overexpressed p53 is wild type. This is in line with the expression profile of BAX and p21, which showed a higher protein expression in these p53 positive tumours (p<0.05 in the carcinomas compared with the non-malignant lesions). Consequently, the overexpressed p53 might be a correlate for dysregulation without loss of function. This, in turn, might be a reason for the good outcome of some patients with thyroid cancer.

Adenocarcinoma, Follicular↗

PubMed2001

Increased distribution of collagen type III and reduced expression of matrix metalloproteinase 1 in patients with diverticular disease.

Diverticular disease is an increasingly common clinical problem especially in Western industrialized countries, but the mechanism by which the disease develops remains unclear. Based on studies showing a structural change in the colonic wall in these patients, we examined whether there are any disorders concerning the collagen metabolism in patients with diverticular disease. Samples of colonic tissue from 13 patients with diverticulitis were compared to 14 controls. We performed a Sirius red test for the overall collagen content and immunohistochemical studies facing differentiation between collagen type I and type III and the expression of matrix metalloproteinases 1 and 13. In the bowel sections of patients with diverticulitis there were decreased levels of mature collagen type I (1.37+/- 0.32 vs. 1.59 +/- 0.31) and increased levels of collagen type III (1.61+/- 0.32 vs. 1.42 +/- 0.42), with a resulting lower collagen ratio I/III. The expression of MMP-I was reduced significantly in the diverticulitis group (4.83 +/- 0.92 vs. 6.02 +/- 1.98) while expression of MMP-13 did not differ significantly between the two groups (1.03 +/- 0.11 vs. 1.04 +/- 0.12). Our findings support the theory of structural changes in the colonic wall as one of the major pathogenic factors in the development of diverticular disease. Further studies must focus on the complex interactions of several extracellular matrix components.

Adult↗

PubMed2001

Functional impairment and complaints following incisional hernia repair with different polypropylene meshes.

The influence of mesh material on the clinical outcome of hernia repair has often been neglected, although recent studies have clearly demonstrated the importance of mesh properties for integration in the abdominal wall. Of particular significance are the amount of mesh material and the pore size. In the following study, patients received different mesh types with distinct amounts of polypropylene and of various pore sizes for incisional hernia repair. We investigated whether the type of material influenced the clinical and functional outcomes. Between 1991 and 1999, 235 patients received polypropylene meshes in a sublay position for incisional hernia repair: 115 patients were implanted with a Marlex heavy-weight mesh (Mhw mesh), 37 patients with an Atrium heavy-weight mesh (Ahw mesh) and 83 with a Vypro low-weight mesh (Vlw mesh). The study protocol included ultrasound examination and 3D-stereography in all patients, with a total follow-up of 24 +/- 13 months (Mhw-mesh), 11 +/- 8 months (Ahw-mesh) and 8 +/- 7 months (Vlw-mesh). Our findings demonstrate that the side effects of mesh implantation, comprising paraesthesia and restriction of abdominal wall mobility, were significantly affected by the type of material implanted. Three-dimensional stereographic examinations were well in accordance with our clinical findings. Our data support the hypothesis that the use of low-weight large-pore meshes is advantageous for abdominal wall function.

Abdominal Muscles↗

PubMed2001

Functional assessment and tissue response of short- and long-term absorbable surgical meshes.

Within the last few years meshes have become essential for the temporary closure of the abdominal cavity to avoid the development of an intra-abdominal compartment syndrome. The interposition of a mesh as an inlay reduces the intra-abdominal pressure and improves markedly the blood circulation, particularly for the intestines and kidneys. Whereas non-absorbable meshes usually tend to produce fistulas in direct contact to the bowels, the interposition of short-term absorbable meshes result in large incisional hernias in almost all cases. In the following study we investigated the functional and histological consequences of a short-term absorbable mesh (polyglactin 910, Vicryl, loss of 50% of its mechanical stability within 3 weeks) and a long-term absorbable mesh (polylactide, LTS, preserved >50% of its mechanical stability for over 1 year). The mesh-modifications were both tested with the aid of three-dimensional stereography, tensiometry, light- (LM) and transmission electron microscopy (TEM) as well as morphometry after implantation intervals of 3, 7, 14, 21, 45, 90, 135 and 180 days in a standardised rat model. The PG-mesh initially revealed a pronounced inflammatory reaction and a significantly increased formation of connective tissue. The extensive arrangement of connective tissue in the interface mesh/recipient tissues correlated to an increased stiffness of the abdominal wall compared to the sham-group. However, a loss of mechanical stability and an increase of elasticity could be detected after 3 weeks of implantation which may be explained by the rapid absorption of the mesh material. In contrast to PG, the LTS-mesh indicated a decreased but persisting inflammatory reaction in the interface mesh-fibres/recipient tissues and a significantly reduced induction of connective tissue. Although, the formation of scar-tissue was diminished compared to PG the LTS-mesh preserved its mechanical stability after 180 days. The results indicate that the frequent development of incisional hernias with short-term absorbable meshes (PG) might be due to the decreased mechanical stability and dilatation of the newly formed connective tissue after 2-3 weeks. Moreover, extensive scar tissue development may promote adhesion formation. The implantation of the long-term absorbable LTS-mesh seems to be favourable with respect to its long-term mechanical stability and the decreased connective tissue formation.

Animals↗

PubMed2001

Moderate hypothermia during cardiopulmonary bypass reduces myocardial cell damage and myocardial cell death related to cardiac surgery.

OBJECTIVES: The goal of this study was to test the hypothesis that moderate hypothermia during cardiopulmonary bypass (CPB) provides myocardial protection by enhancing intra-myocardial anti-inflammatory cytokine balance. BACKGROUND: Moderate hypothermia during experimental CPB stimulates production of interleukin-10 (IL10) and blunts release of tumor necrosis factor-alpha (TNFalpha). METHODS: Twelve young pigs were assigned to a temperature (T degrees ) regimen during CPB: moderate hypothermia (T degrees : 28 degrees C; n = 6) and normothermia (T degrees : 37 degrees C; n = 6). Intra-myocardial TNFalpha- and IL10-messenger RNA were detected by competitive reverse transcriptase polymerase chain reaction and quantification of cytokine synthesis by Western blot. Levels of cardiac troponin I (cTnI) in cardiac lymph and in arterial and coronary venous blood were examined during and after CPB. Myocardial cell damage was assessed by histologic and ultrastructural anomalies of tissue probes taken 6 h after CPB. RESULTS: Synthesis of IL10 was significantly higher, while that of TNFalpha was significantly lower, in pigs that were in moderate hypothermia during surgery than in the others. In contrast with normothermia, moderate hypothermia was also associated with significantly lower cumulative cardiac lymphatic flow during and after CPB, significantly lower lymphatic cTnI concentrations after CPB, significantly lower percentages of myocardial cell necrosis and a significantly lower score of ultrastructural anomalies of myocardial cells. While the percentage of apoptotic cells was not different between groups, the apoptosis/necrosis ratio tended to be higher in animals that were in moderate hypothermia during surgery. In all animals, TNFalpha synthesis correlated positively while IL10 production correlated negatively with necrosis and total cell death, respectively. CONCLUSIONS: Our results suggest that moderate hypothermia during CPB provides myocardial protection by enhancing intra-myocardial anti-inflammatory cytokine balance.

Animals↗

PubMed2001

The chorioallantoic membrane of the chick embryo as a simple model for the study of the angiogenic and inflammatory response to biomaterials.

Angiogenesis is essential in wound healing and a common feature in chronic inflammation which is crucially involved in the biological response to biomaterials. A useful system to evaluate the angiogenic activity and the inflammatory potency of various agents is the chorioallantoic membrane (CAM) of the chick embryo. Here we examined its response to different biomaterials. Smooth materials such as PVC or the polyurethane Tecoflex either unmodified or modified by an OH- or N(CH(3))(3)(+)-end group (HEMA or MAPTAC) inhibited angiogenesis and did not induce the formation of granulation tissue. The anti-angiogenic effects of PVC, Tecoflex and its HEMA modification, however, were only seen at an early stage of development. In contrast, the MAPTAC modified Tecoflex inhibited angiogenesis over the whole time. Rough materials, e.g. filter paper or a collagen/elastin membrane, stimulated angiogenesis and induced the formation of inflammatory tissue. Histological analysis revealed that the filter material was homogeneously populated with cells consisiting mainly of macrophages, fibroblasts and endothelial cells. The collagen/elastin membrane was only partially infiltrated with cells. Among those also clusters of granulocytes were present pointing to an acute inflammatory process. These data show that the angiogenic activity and inflammatory response of biomaterials strongly depend on the chemical composition and the physical structure of the material. The CAM assay appears to be a useful tool for studying biocompatibility.

Journal Article↗

PubMed2001

Role of HSP70i in regulation of biomaterial-induced activation of human monocytes-derived macrophages in culture.

The functioning of an implant depends on the material properties and the wound-healing process. The latter is led by an inflammatory reaction guided mainly by monocyte/macrophage activity. This in vitro study investigated human monocytes/macrophages in culture from 2 h to 10 days on silicone, polyurethane, teflon and TCPS. Analysis of cytokine release by ELISA showed that maturing macrophages have different capacities to produce cytokines TNFalpha, IL10, IL8 and GM-CSF. The long culture-mature macrophages on all polymers produced comparable low levels of TNFalpha, IL10 and IL8. Monocytes/macrophages on polyurethane and teflon, and those on silicone only in long culture-time produced high GM-CSF amounts, where as those on TCPS exhibited low levels of GM-CSF. FACS analysis revealed that HSP70i was highly inducible after short time culture yet this high level was maintained in long culture-mature macrophages on TCPS only, whereas on other polymers the mature macrophages showed a high reduction in HSP70i level, which demonstrated a high stress-response by cells on TCPS. Accordingly, CLSM-analysis revealed low nuclear NF-kappaB in cells on TCPS and high nuclear NF-kappaB in mature macrophages on silicone and polyurethane, showing a high cellular activation on the latter two polymers. This corresponded also to the high mitochondrial activity by XTT metabolism displayed by the mature macrophages on polyurethane >/= silicone > teflon > TCPS. These data show a correlation of (1) cytokines (TNFalpha, GM-CSF) and HSP70i, (2) NF-kappaB and HSP70i by monocytes/macrophages after contact with polymers. Thus, HSP70i might be a useful molecular candidate for exploring biomaterial-induced inflammatory reaction.

Journal Article↗

PubMed2001

Inflammatory response to a porcine membrane composed of fibrous collagen and elastin as dermal substitute.

The inflammatory response to a collagen/elastin membrane was studied by measuring the expression of cytokines and function associated antigens in human macrophages. Additionally the angiogenic and inflammatory activity in the chorioallantoic membrane of the chick embryo (CAM-assay) was investigated. Macrophages cultured on the membrane expressed IL-1beta mRNA as early as after 4 hours. During prolonged culturing IL-1beta mRNA levels decreased. Messenger RNA for IL-8 was detectable over the whole culture period. The anti-inflammatory cytokine IL-10 was expressed up to one day only. Phenotypic analysis revealed a decrease in the number of chronic inflammatory 25F9 positive macrophages not migrating into the membrane but a presence of these cells together with the acute inflammatory 27E10 macrophages within the membrane whereas the anti-inflammatory subtype RM3/1 was absent. In the CAM-assay the membrane stimulated angiogenesis and induced the formation of granulation tissue. Histological analysis showed that the membrane was infiltrated with macrophages, fibroblasts and endothelial cells and locally with granulocytes. These data show that the collagen/elastin membrane causes activation of macrophages, angiogenesis and the formation of inflammatory tissue. Although these processes are essential for wound healing the type of inflammation points to a chronic process which might counteract an efficient scar formation.

Journal Article↗

PubMed2001

Effects of single and multiple doses of perfluorocarbon in comparison with continuous partial liquid ventilation on gas exchange and lung pathology in newborn surfactant-depleted pigs.

OBJECTIVE: To compare the efficacy of single, multiple, and continuous application of perfluorocarbon (PFC) FC-77 on gas exchange and lung pathology in a prolonged 24-hr study. DESIGN: Controlled animal trial. SETTING: Research laboratory in a university setting. SUBJECTS: Twenty-one newborn piglets (mean weight 1.94 kg). INTERVENTIONS: After intubation and instrumentation, the anesthetized animals were randomized in three groups: a) animals receiving one 1-hr session of partial liquid ventilation (PLV) followed by 23 hrs of conventional ventilation (CV), designated as the single PLV (S-PLV) group; b) animals receiving multiple 1-hr sessions of PLV with intermittent CV, designated as the multiple PLV (M-PLV) group; and c) animals receiving continuous PLV over 24 hrs, designated as the continuous PLV (C-PLV) group. After lung injury was induced with repeated saline lavage, specific ventilatory treatment was initiated. The oxygenation index, Pao2/Fio2 ratio, and ventilatory efficacy index were determined before and after lung injury and during the 24-hr course. After 24 hrs, the lungs were removed for histopathologic examination. MEASUREMENTS AND MAIN RESULTS: Gas exchange variables improved within 60 mins in all groups after the initiation of the specific ventilatory treatment (p < .01). The best outcome was observed in the C-PLV group, which provided a continuously stable gas exchange over the 24-hr period. S-PLV initially improved gas exchange, but after 6 hrs all variables were impaired when compared with C-PLV (p < .01). M-PLV transiently improved gas exchange variables after each PFC application; however, M-PLV was associated with a significant deterioration of all pulmonary variables during the 24-hr course. The lungs of the animals in the M-PLV group demonstrated an increased lung injury score (p < .01) and increased morphometric values (p < .05) when compared with C-PLV. CONCLUSIONS: In surfactant deficient lungs, single and multiple applications of PFC only transiently improved oxygenation. Multiple PFC fillings with intermittent gas ventilation led to a deterioration of gas exchange during the 24-hr study and severe lung damage. Continuous PLV provides the best gas exchange and the most favorable histopathologic outcome.

Animals↗

PubMed2001

Influence of temperature during cardiopulmonary bypass on leukocyte activation, cytokine balance, and post-operative organ damage.

This study examined the hypothesis that core temperature (T(o)) during cardiopulmonary bypass (CPB) influences the perioperative systemic inflammatory response and post-operative organ damage. Twenty-four pigs were assigned to a T(o) regimen during CPB: normothermia (T(o) 37 degrees C; n = 8), moderate hypothermia (T(o) 28 degrees C; n = 8), or deep hypothermia (T(o) 20 degrees C; n = 8). Perioperative leukocyte activation, endotoxin release, and production of tumor necrosis factor-alpha (TNFalpha) and interleukin-10 (IL10) were examined with regard to post-operative organ damage, which was scored at histological examination of tissue probes of heart, lungs, liver, kidney, and ileum, taken 6 h after CPB. Total blood leukocyte count and TNFalpha plasma levels during CPB were significantly lower and IL10 levels were significantly higher in the moderate hypothermic group than in both other groups. Elastase activity, leukotriene B4-, and endotoxin levels were not affected by T(o) regimen. Moderate hypothermia was associated with the lowest histological organ damage score and normothermia with the highest. In all animals organ damage score for heart, lungs, and kidneys correlated significantly with TNFalpha levels at the end of CPB. Our data demonstrate a clear relationship between TNFalpha production during cardiac operations and post-operative multiple-organ damage. Moderate hypothermia, by stimulating IL10 synthesis and suppressing TNFalpha production during CPB, might provide organ protection.

Animals↗

PubMed2001

Prototype percutaneous thrombolytic device: preclinical testing in subacute inferior vena caval thrombosis in a pig model.

PURPOSE: To develop an animal model of subacute inferior vena caval (IVC) thrombosis and apply this model in evaluating the safety and efficacy of a prototype percutaneous thrombolytic device for restoring patency. MATERIALS AND METHODS: In 11 pigs, a stent with a ligature in the middle was placed in the IVC. Thrombin was injected to induce thrombosis. Hemostasis was achieved by using an occlusion balloon. The stent was ligated to prevent thrombus migration. Five to 8 days after thrombus induction, the ligature was broken and the stent fully deployed. In 10 animals, thrombectomy was performed by using the percutaneous thrombolytic device. A vena caval filter was inserted at the beginning of each declotting procedure. Thrombus removal percentage was estimated and pulmonary angiograms obtained to detect embolism before and after thrombectomy. The IVC was analyzed histologically. To determine thrombus composition, one animal was sacrificed without thrombectomy. Concerning procedural safety, failure of the stent delivery system, stent migration, and venous perforation due to balloon inflation and the stent placement or thrombectomy procedure were evaluated. RESULTS: Thrombus creation was successful in all animals. Fragmentation led to 75%--100% thrombus removal with flow restoration in all cases. There were no episodes of stent delivery failure, stent migration, or venous perforation. No significant pulmonary embolism was observed. In one case, a vessel dissection was identified at histologic examination. CONCLUSION: In this animal model of IVC thrombosis, the percutaneous thrombolytic device is effective and safe for clot removal.

Animals↗

PubMed2001

The influence of hypoalbuminemia on maximal flow rates and transmembrane pressure during plasmapheresis--an in vitro study.

BACKGROUND: Plasmapheresis has been used for the treatment of acute liver failure (ALF). In these patients, hypoalbuminemia is often observed. Since albumin improves the disaggregability of erythrocytes, hypoalbuminemia might deteriorate rheology and thus influence the overall performance of plasmapheresis. METHODS: Hypoalbuminemia was mimicked by using porcine blood because of its physiologically low albumin/globulin ratio (AGR). Filters (n = 16) were integrated in a closed extracorporeal in vitro system. In the control group (n = 8), native porcine blood (AGR 0.8) was used. In the study group (n = 8), we used porcine blood supplemented with human albumin to obtain the human AGR value of 1.2. Two different heparinization protocols were compared in each group (2.5 IU/ml: n = 4 with albumin and n = 4 without albumin versus 5 IU/ml: n = 4 with and n = 4 without albumin). RESULTS: In both heparinization protocols the higher AGR led to lower transmembrane pressure (TMP) levels compared to the lower AGR. The reduced TMPs enabled higher blood flow and filtration rates. CONCLUSION: Maintenance of a physiological AGR in ALF patients might improve the performance of plasmapheresis and--as opposed to raised heparinization--contribute to a safer application.

Animals↗

PubMed2001

Enhancing filtration rates by the use of blood flow around the capillaries of plasmafilters: an in vitro study.

As the low clearance rate of plasmaseparation limits its use in the treatment of patients suffering from liver failure, sepsis or MOF, we intend to develop strategies for a plasmaseparation unit which increases plasmafiltration rates. Our first question focused on whether commercially available plasmaseparation filters, and in particular their membranes, are suitable for the inversion of blood and plasma compartments. This experimental study was performed using in vitro systems. Commercially available plasmafilters PF2000N (Gambro) and Plasmaflo (Asahi) were compared in both their normal operating mode with blood flow through the capillary lumen, and in the inverse mode. Inverse mode means that blood flows through the outer space of the capillaries while plasma was obtained from the lumen. Heparinised porcine blood (5 I.U./ml) was used in a heated, recirculating in vitro circuit. Our main results were that the normal use of both filter types Plasmaflo and PF2000N enabled maximal blood flows (Qb) of 200 ml/min and filtration rates (Qf) of 25-40 ml/min. Operating the filters in the inverse mode enabled Qb up to 500 ml/min and Qf up to 100 ml/min. Hemolysis, platelet counts and coagulation parameters did not differ significantly regardless of whether the normal or inverse mode was used. The tested plasmafiltration membranes appear to be suitable for use in inverse mode. Although in our experiments, hemocompatibility tests did not indicate severe problems induced by the module geometry, the development of a module specially constructed for blood flow outside of the hollow fibers appears to be necessary in order to minimise shunts and low perfusion areas.

Animals↗

PubMed2000

[Pathology of traditional surgical nets for hernia repair after long-term implantation in humans].

The widespread use of alloplastic materials as the standard procedure for hernia repair makes an evaluation of the long-term integration of these implants imperative. A total of 121 explanted meshes (mean implantation time 23.2 & 19.7 months) of polypropylene (Atrium((R)), n = 20; Marlex((R)), n = 50; Prolene((R)), n = 21), Polyester (Mersilene((R)), n = 19) and PTFE (Gore-Tex((R)), n = 11) were analyzed in regard to the tissue and cell response within the interface mesh-fiber/tissue. The mesh samples were investigated by light and electronmicroscopy, as well as immunohistochemistry. The morphometric results confirmed a persisting inflammatory proliferative foreign-body reaction with increased cell turnover in the recipient tissues. This reaction is mainly influenced by the selected mesh modification. The consequences of the arising "chronic wound" are discussed in detail, in particular with regard to possible malignant transformation.

Adult↗

PubMed2000

[Preserving autonomic nerves in rectal surgery. Results of surgical preparation on human cadavers with fixed pelvic sections].

INTRODUCTION: Preservation of sexual function and voiding capacity after rectal cancer surgery has increased after adopting the technique of nerve-sparing dissection and total mesorectal excision. Still the rate of sexual and urinary dysfunction ranges between 25 and 67%. The precise locations where nerve damage occurs have not been looked at systematically. MATERIAL AND METHODS: In ten human corpses and two formalin-fixed human pelvises the autonomous pelvic nerves were isolated. Their relation according to surgical mobilization of the rectum were photodocumented. RESULTS: Pelvic autonomous nerves are clearly defined structures with only minor interindividual variability. The inferior mesenteric plexus forms a dense network around the inferior mesenteric artery (AMI) to a distance of 5 cm from the aorta. The distance between the lateral rectum and the pelvic plexus is only 2-3 mm. The anterior rectum is almost directly adherent to the neurovascular bundle, separated only by Denonvillier's fascia. The parasympathetic branches of the sacral segments S2-S5 cannot be isolated using the standard surgical approach. CONCLUSION: (1) The nomenclature of fascias and the course of the autonomous pelvic nerves is not clearly defined in the literature; (2) a high tie of the AMI leads to damage of the sympathetic nerves; (3) the narrow space between the anterior and lateral rectum makes sharp dissection under direct vision necessary; (4) fascias and nerves can be used as guiding structures during mobilization; (5) a preservation of selected parasympathetic roots in the small pelvis is not feasible using the standard surgical approach.

Autonomic Nervous System↗

PubMed2000

Partial liquid ventilation with surfactant: effects on gas exchange and lung pathology in surfactant-depleted piglets.

OBJECTIVE: To evaluate the effects of 24 h partial liquid ventilation (PLV) with and without surfactant (S) treatment on gas exchange and lung injury in a newborn animal model of S deficiency. DESIGN: A prospective, controlled, in vivo animal laboratory study. SETTING: Research laboratory in a university setting. SUBJECTS: Twenty-four pathogen-free, male piglets (mean weight 1.9 kg, age 1-3 days). INTERVENTIONS: The animals were randomised in four groups: PLV with FC-77 combined with conventional ventilation (PLV/CV) versus S + PLV/CV and PLV combined with high frequency oscillatory ventilation (PLV/HFOV) versus S + PLV/HFOV. The piglets were anaesthetised, intubated and instrumented with vascular catheters. Thirty minutes after lung injury had been induced with repeated saline lavage, S animals received natural S. Thirty minutes after surfactant substitution PLV with FC-77 was started. The oxygenation index (OI), PaO(2)/FIO(2) ratio, PaCO(2) and the ventilatory efficacy index were determined before and during PLV. After 24 h the lungs were removed for histopathological examination. MEASUREMENTS AND MAIN RESULTS: Within 60 min after the initiation of PLV, all animals demonstrated improvements of the OI and PaO(2)/FIO(2) ratio compared to the values after lung injury. However, at 18 and 24 h of PLV, the OI and PaO(2)/FIO(2) ratio were significantly worse in the S + PLV/CV and S + PLV/HFOV groups compared to the groups without S. PaCO(2) was higher at 18 and 24 h when S was used in PLV/HFOV (p < 0.05). A semi-quantitative lung injury score revealed most severe lung damage in the S + PLV/HFOV group. CONCLUSIONS++: The combination of S and PLV with FC-77 led to an impaired gas exchange and did not further protect the animal from lung injury.

Animals↗

PubMed2000

Benign metastasizing leiomyoma: a cytogenetically balanced but clonal disease.

Benign metastasizing leiomyoma (BML) is a rare condition, characterized by the occurrence of multiple smooth-muscle nodules, most often located in the lung after previous hysterectomy because of histologically benign appearing leiomyoma. Although the condition resembles a metastatic process, case studies provided evidence that it may be the result of an intravenous leiomyomatosis or an independent and multifocal smooth-muscle proliferation. Comparative genomic hybridization and X-chromosome inactivation analysis were used in a case of BML to determine whether pulmonary and uterine tumors are related one to another. A balanced karyotype, previously reported in leiomyomas and an identical X-chromosome inactivation pattern found in all tumorlets, is most consistent with a monoclonal origin of both uterine and pulmonary tumors and the interpretation that pulmonary lesions are metastatic.

Adult↗

PubMed2000

Comparison of two stent-grafts with different porosity: in vivo studies in a sheep model.

PURPOSE: To compare two stent-grafts with a polyurethane-carbonate (PUC) polymer lining of different pore size and water permeability in the iliac arteries of sheep. MATERIALS AND METHODS: Two stent-grafts with an inner PUC-lining of normal and low water permeability (normal, 1,200 mL/min/cm2; low, 280 mL/min/cm2; pressure gradient, 20 mm Hg) were implanted in each of 16 sheep. Hoop strength was two times higher in low-permeable than in normal-permeable stent-grafts. Patency was monitored with use of angiography and intravascular ultrasound (IVUS) after 1, 3, and 6 months. The sheep were killed after 1 or 6 months. Specimens were studied histologically. IVUS and histologic data were analyzed statistically. RESULTS: IVUS measurements showed a wider patent lumen of the low- compared to the normal-permeable prostheses at all time points (P < .03). This is likely due to the greater hoop strength of the low-permeable stent-graft. After 1 month, both types of prostheses demonstrated complete transprosthetic tissue penetration and were covered with neointima and endothelium. The neointimal area was greater in low- than in normal-permeable stent-grafts (1 month, P < .005; 6 months, P < .03). CONCLUSIONS: Presumably, the higher permeability of the normal-permeable stent-grafts led to the reduced neointimal area by improving transprosthetic capillary ingrowth and endothelialization.

Angiography↗