Although previous studies have shown that the lesions of multiple sclerosis may involve the cerebral cortex, there is little published research on the prevalence and distribution of such lesions. Using neuropathological techniques and MRI, a series of studies has been undertaken in order to assess this, in particular to identify their relationship to cortical veins. A serial MRI study showed that the use of gadolinium proffered an increase in cortical lesion detection of 140% and showed that 26% of active lesions arose within or adjacent to the cortex. In a post-mortem study, MRI under-reported lesions subsequently analysed neuropathologically, particularly those arising within the cortex. In a further 12 cases examined, 478 cortical lesions were identified, of which 372 also involved the subcortical white matter. Seven different lesion types were identified; the majority arose within the territory of the principal cortical veins, whilst the remaining quarter arose within the territory of the small branch or superficial veins. Small cortical lesions are common in multiple sclerosis and are under-reported by MRI. Investigation of the cortical venous supply shows how such lesions may arise, and why the majority also involve the underlying white matter. (+info)
The size and fibre composition of the corpus callosum with respect to gender and schizophrenia: a post-mortem study.
In this study the cross-sectional area (in n = 14 female controls, 15 male controls, 11 female patients with schizophrenia, 15 male patients with schizophrenia) and fibre composition (in n = 11 female controls, 10 male controls, 10 female patients with schizophrenia, 10 male patients with schizophrenia) of the corpus callosum in post-mortem control and schizophrenic brains was examined. A gender x diagnosis interaction (P = 0.005) was seen in the density of axons in all regions of the corpus callosum except the posterior midbody and splenium. Amongst controls, females had greater density than males; in patients with schizophrenia this difference was reversed. A reduction in the total number of fibres in all regions of the corpus callosum except the rostrum was observed in female schizophrenic patients (P = 0.006; when controlling for brain weight, P = 0.053). A trend towards a reduced cross-sectional area of the corpus callosum was seen in schizophrenia (P = 0.098); however, this is likely to be no more than a reflection of an overall reduction in brain size. With age, all subregions of the corpus callosum except the rostrum showed a significant reduction in cross-sectional area (P = 0.018) and total fibre number (P = 0.002). These findings suggest that in schizophrenia there is a subtle and gender-dependent alteration in the forebrain commissures that may relate to the deviations in asymmetry seen in other studies, but the precise anatomical explanation remains obscure. (+info)
Determination of Hounsfield value for CT-based design of custom femoral stems.
Ct and advanced computer-aided design techniques offer the means for designing customised femoral stems. Our aim was to determine the Hounsfield (HU) value of the bone at the corticocancellous interface, as part of the criteria for the design algorithm. We obtained transverse CT images from eight human cadaver femora. The proximal femoral canal was rasped until contact with dense cortical bone was achieved. The femora were cut into several sections corresponding to the slice positions of the CT images. After obtaining a computerised image of the anatomical sections using a scanner, the inner cortical contour was outlined and transferred to the corresponding CT image. The pixels beneath this contour represent the CT density of the bone remaining after surgical rasping. Contours were generated automatically at nine HU levels from 300 to 1100 and the mean distance between the transferred contour and each of the HU-generated contours was computed. The contour generated along the 600-HU pixels was closest to the inner cortical contour of the rasped femur and therefore 600 HU seem to be the CT density of the corticocancellous interface in the proximal part of cadaver femora. Generally, femoral bone with a CT density beyond 600 HU is not removable by conventional reamers. Thus, we recommend the 600 HU threshold as one of several criteria for the design of custom femoral implants from CT data. (+info)
The inadequacy of standard radiographs in detecting flaws in the cement mantle.
Radiological assessment of the cement mantle is used routinely to determine the outcome of total hip replacement. We performed a simulated replacement arthroplasty on cadaver femora and took standard postoperative radiographs. The femora were then sectioned into 7 mm slices starting at the calcar, and high-resolution faxitron radiographs were taken of these sections. Analysis of the faxitron images showed that defects in the cement mantle were observed up to 100 times more frequently than on the standard films. We therefore encourage the search for a better technique in assessing the cement mantle. (+info)
Extent and composition of coronary lesions in relation to fat distribution in women younger than 50 years of age.
To ascertain the relationship between the extent and composition of coronary arterial lesions and the regional distribution of fat in healthy women younger than 50 years of age, a series of 30 forensic autopsy cases were investigated. Body height and weight, waist and hip circumferences, and the thickness of the subscapular and abdominal subcutaneous fat were measured; the body mass index (BMI) and waist-to-hip ratio (WHR) were calculated, and omental and mesenteric fat deposits were weighed. The extent of coronary lesions was measured by planimetry, and the thickness of the intima-media was measured by computerized image analysis. Intimal macrophage foam cells and smooth muscle cells were detected by immunohistochemistry, and macrophages were quantified. The intima media thickness in the left anterior descending artery, circumflex artery, and right coronary artery varied significantly across the tertiles of WHR when age and BMI were adjusted, being highest when WHR exceeded 0.87. The thickest lesions also contained the largest numbers of macrophage foam cells. The intima-media thicknesses were highest with increased amounts of intraperitoneal fat. These results indicate that the severity of clinically silent coronary lesions in younger female individuals is associated with increased WHR and increased amounts of intraperitoneal fat. These results emphasize the importance of WHR as a coronary risk indicator in younger women. (+info)
Effect of dialyser biocompatibility on recovery from acute renal failure after cadaver renal transplantation.
BACKGROUND: It has been reported that patients with acute renal failure (ARF) requiring haemodialysis show an improved recovery of renal function when the dialysis treatment is performed using a biocompatible membrane rather than a bioincompatible membrane. However, most recent published human trials have not been able to confirm these findings. METHOD: Over a 2-year period, we prospectively studied 53 patients with ARF after cadaver renal transplantation who required haemodialysis and randomized them into two treatment groups. One group underwent dialysis with a cuprophane membrane and the other group underwent haemodialysis with a more biocompatible membrane, polysulfone. All patients received an immunosuppressive regimen which included azathioprine, prednisone and cyclosporine. RESULTS: There was no difference by patient characteristics or immunosuppressive regimen before acute tubular necrosis (ATN) recovery. In both groups the number of haemodialysis sessions required prior to the recovery of renal function (6.57+/-2.79 vs 6.05+/-2.40), the number of oliguric days (16.25+/-5.14 vs 14.40+/-4.67) and the number of hospital days (33.38+/-12.85 vs 30.10+/-11.00), were not statistically different. There was also no difference in long-term allograft outcome. CONCLUSION: Our data demonstrate that the use of a more biocompatible membrane had no influence on the recovery from acute renal failure after renal transplantation. (+info)
Laparoscopic aortofemoral bypass grafting: human cadaveric and initial clinical experiences.
PURPOSE: Postoperative complications are mainly related to the surgical trauma derived from the extensive abdominal incision and dissection after a conventional aortofemoral bypass grafting procedure. In an attempt to reduce postoperative complications, a concept of video-endoscopic vascular surgery on the infrarenal aortoiliac artery has been developed. On the basis of our experience with the practicability of video-endoscopic vascular surgery in the pelvic region in an animal study and in a pilot study of human cadavers, the purpose of this report was to describe three different methods that we evaluated on human cadavers and that we partly applied to patients. METHODS: In this experimental study, three different approaches were used to perform video-endoscopic aortofemoral bypass grafting. We performed an observational trial on human corpses (n = 24) with the transabdominal-retroperitoneal approach (TARA), the extraperitoneal approach (EPA), and the transabdominal left paracolic approach (TAPA). The EPA also was applied to patients with aortoiliac occlusive diseases. RESULTS: The TARA on cadavers (n = 4) soon was abandoned because it caused a burdensome sliding of the intestine into the operative field adjacent to the renal vessels, particularly in cases with obese subjects. In comparison, the TAPA (n = 6) with right-sided positioning of the patient retained the intestine in the right upper abdomen throughout the procedure. Until a surgeon actually is acquainted with the anatomic landmarks and the laparoscopic preparation technique, the EPA (n = 14) is a challenging procedure that necessitates thorough training. As with the TAPA, the EPA represents a procedure that reveals constant exposure of the operating field, even in cases with obese subjects. In the clinical observational study (n = 7), aortobifemoral bypass grafting was achieved totally laparoscopically with the EPA. The mean operating time was 6.5 hours and ranged from 3 to 10 hours. Blood transfusions were necessary after surgery in three patients (range, 1 to 3 red packed blood cells). One patient, who had had occlusion of the inferior mesenteric artery, died of ischemic colitis at postoperative day 10. The other patients had uneventful postoperative courses with minor wound discomfort. CONCLUSION: Laparoscopic vascular surgery seems to be a promising procedure to minimize postoperative complications. On the basis of our experience, we do not favor the TARA. Because it necessitates steep Trendelenburg positioning to displace intra-abdominal organs, the TARA is not an appropriate approach, particularly in obese and cardiopulmonary frail cases. Contrarily, the TAPA and the EPA deliver potentially better results in terms of exposing the operative field and thus reducing operating time and perioperative morbidity rates. A prospective cadaveric and clinical trial may be justified to further evaluate the use of these surgical techniques. (+info)
Local inhibition of tissue factor reduces the thrombogenicity of disrupted human atherosclerotic plaques: effects of tissue factor pathway inhibitor on plaque thrombogenicity under flow conditions.
BACKGROUND: Plaque disruption and subsequent thrombus formation lead to acute coronary syndromes and progression of atherosclerotic disease. Tissue factor (TF) appears to mediate plaque thrombogenicity. Tissue factor pathway inhibitor (TFPI) is the major physiological inhibitor of TF. This study analyzes the role of TF on thrombogenicity of disrupted human atherosclerotic plaques and the therapeutic possibilities of its specific inhibition. METHODS AND RESULTS: Human atherosclerotic and normal arterial segments were exposed to heparinized blood at flow conditions modeling medium-grade coronary stenosis in the Badimon perfusion chamber. The antithrombotic effects of the specific inhibition of plaque TF was assessed by reduction in the deposition of radiolabeled platelets and fibrin(ogen) and immunohistochemical analysis of perfused arteries. TF activity was inhibited by both recombinant TFPI and a polyclonal antibody against human TF. Human lipid-rich plaques were more thrombogenic than less advanced atherosclerotic plaques. Specific inhibition of TF activity reduced plaque thrombogenicity, inhibiting both platelet and fibrin(ogen) deposition (580 versus 194 plateletsx10(6)/cm2; P<0.01, and 652 versus 172x10(12) molecules of Fg/cm2; P<0.05, respectively) and thrombosis (immunohistochemistry). CONCLUSIONS: This study documents the key role of TF activity in acute arterial thrombosis after atherosclerotic plaque disruption and provides evidence of the benefit of blocking plaque TF activity. Therefore the inhibition of the TF pathway opens a new therapeutic strategy in the prevention of acute coronary thrombosis after plaque disruption. (+info)