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Biomedical subjects

D Heim

Publications and source records attributed to D Heim.

At least 55 records · Page 3Linked to original sources
PubMed1998

Quantitative immunophenotypic characterization, cryopreservation, and enrichment of second- and third-trimester human fetal cord blood hematopoietic stem cells (progenitor cells).

OBJECTIVE: The aims of this study were (1) to assess the hematopoietic stem cell (progenitor cell) contents of umbilical cord blood samples from second-trimester and early-third-trimester fetuses versus term fetuses and (2) to determine the feasibility of cryopreservation and enrichment of cord blood from fetuses of different gestational ages. STUDY DESIGN: Cord blood between 13 and 42 weeks' gestation (n = 31) was sampled after delivery or fetal expulsion. Fluorescence-activated cell sorting was used to measure CD34(+) and CD34(+)CD38(-) cell numbers. Samples were cryopreserved with 10% dimethylsulfoxide, and CD34(+) enrichment was performed by magnetically activated cell sorting with the MiniMACS system (Miltenyi Biotech, Bergisch Gladbach, Germany). Kruskal-Wallis analysis of variance and the Mann-Whitney U test were used for analysis of data. RESULTS: CD34(+) and CD34(+)CD38(-) cell contents were significantly higher in second- and early third-trimester fetuses than in term fetuses (CD34(+) 2.57% +/- 0.38%, 1.48% +/- 0. 31%, and 0.7% +/- 0.13%, respectively, P =.0067; CD34(+)CD38(-) 0. 72% +/- 0.26%, 0.18% +/- 0.05%, and 0.06% +/- 0.02%, respectively, P =.0132). Mononuclear cell recovery, viability, and CD34(+) cell purity after cryopreservation and enrichment were similar among different gestational ages. CONCLUSION: Cord blood stem cell content decreases significantly from the second trimester to term. Cryopreservation and enrichment of these cells from earlier gestational ages is feasible. This might be especially useful for allogeneic stem cell transplantation and for in utero gene therapy.

ADP-ribosyl Cyclase↗
PubMed1998

[182 offspring of cows with bovine spongiform encephalopathy (BSE) in Switzerland. 2. Epidemiology and pathological findings].

In order to detect lesions of a spongiform encephalopathy and/or accumulation of the protease resistant prion protein (PrPres), 182 offspring of cows affected with BSE were examined neuropathological and immunohistochemically. Neither spongiform encephalopathy nor PrPres accumulation were found. In seven animals other neuropathological lesions were seen, significant ones in three. Because of the small risk of exposure to contaminated feed in these animals, nearly all of which were born after the introduction of the protein feed ban for ruminants, the occurrence of spongiform encephalopathy in this series of BSE offspring would be suggestive of maternal transmission. However, the value of the study in this respect is quite limited. Only half of the animals were old enough to develop clinical and pathological evidence of the disease. If a maternal effect on the risk for the offspring is only to be expected during the last 6 months of the incubation of the dam as suggested by British investigations, only few animals in this study would fulfil the requirement of having been born during this critical period. Since it cannot be entirely excluded that the BSE agent transiently invades extraneural tissues in the early stages of infection, the above mentioned restriction to the final 6 months of the incubation time of the dam would not necessarily be applicable to all situations. We concluded that this study supports previous observations according to which maternal transmission of BSE is at best a rare event.

Animals↗
PubMed1997

[Frequency of neurologic diseases in cattle].

The cases of neurological diseases at the Institute of Animal Neurology, University of Berne, from 1985-1994 were assessed. During this period 532 cattle with neurological symptoms were examined. After 1980 differential diagnostic investigation of rabies negative brains were not pursued anymore and the number of examined cattle brains had declined to 25-30 per year. With the occurrence of bovine spongiform encephalopathy (BSE) in 1990 in Switzerland the number of cattle brains examined has increased to 75-80 yearly. The most frequently diagnosed neurological diseases found are BSE, followed by listeriosis and viral encephalitides.

Animals↗
PubMed1995

Intramedullary nailing and pulmonary embolism: does unreamed nailing prevent embolization? An in vivo study in rabbits.

Pulmonary embolism in reamed femoral nailing has been reported and discussed over recent years. Does an unreamed nailing technique with a solid nail prevent this rare but serious complication of intramedullary fixation? In an animal model in rabbits, we studied the pathophysiologic impact on pulmonary function and the impact on hemostasis of reamed and unreamed nailing of intact femora and tibiae, and of femoral fracture in relation to intramedullary pressure. No statistical difference of PaO2, PaCO2, and PCO2et was found in the femur whether a reamed or unreamed procedure was performed. Two of six animals with unreamed femoral nailing, one of six animal with reamed femoral nailing, and one of five animals with a femoral fracture fulfilled four of four or three of four criteria for embolization (increase of the difference of PaCO2 and PCO2et, decrease of PaO2, increase of blast cells in central-venous blood and bone marrow/fat in histologic section of the lungs and bone). Tibial nailing did not alter pulmonary function in either group. Intramedullary pressure was increased in all animals with perioperative impairment of pulmonary function (375 to 676 mbar). Analysis of the hemostatic results showed a significant difference of platelet activation in reamed versus unreamed nailing of the femur 1 hour after nailing (p < 0.01) and a significant decrease of fibrinogen and antithrombin III (p < 0.001/p < 0.01) in reamed femoral nailing. We conclude that unreamed nailing of the femur with a solid rod may also cause bone marrow embolization with alteration of pulmonary function as long as an important increase of the intramedullary pressure is generated during the nailing procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[Experimental results of intra-osseous pressure in various surgical procedures of the long bones].

The generation of intramedullary pressure in medullary nailing and total hip and knee replacement is now well-known. This pressure increase is generally recognized as an important factor in local and systemic bone marrow embolization. In various clinical and experimental studies methods for reducing the intramedullary pressure build-up have been tested. In prosthetic joint replacement a distal venting hole, a large insertion hole and a modified technique for cement insertion have been shown to be valuable methods for pressure reduction. In intramedullary nailing, a distal venting hole, an unreamed nailing technique using solid nails and slow nailing did not alter the pressure increase effectively. Measures such as redimensioning the flexible drive, possibly in combination with special reamer heads, reduction of the insertion force or use of irrigation suction drainage during reaming of the medullary canal represent potential ways preventing this undesirable side effect in this popular internal fixation technique.

Bone Marrow↗
PubMed1994

Pinless calcaneus traction: a preliminary report.

Calcaneus traction with a Steinmann-pin or K-wire inserted into the dorsal aspect of the calcaneus is a common temporary procedure in fractures of the lower leg when internal fixation has to be delayed. Infection due to this simple manoeuvre is rare, but is a very serious complication. In 1991, a so-called pinless external fixator was introduced in clinical trials, based on the idea of external fixation without transosseus pins, thus preserving local blood supply and lowering the risk of pin track infection. This pinless clamp also represents a handy tool for calcaneus traction. We have used this pinless clamp for calcaneus traction in 39 patients without any major problems or complications. Of these, 29 patients were scheduled for delayed internal fixation, and in 10 patients this clamp was used intraoperatively in closed tibial nailing for traction on the fracture table. Tips and tricks for the use of this pinless clamp, and its advantages and disadvantages are discussed.

Adolescent↗
PubMed1994

Expression of LDL receptor-related protein/alpha 2-macroglobulin receptor in human normal and atherosclerotic arteries.

Low-density lipoprotein receptor-related protein/alpha 2-macroglobulin receptor (LRP/alpha 2-MR) is a multifunctional cell-surface receptor that is responsible for the clearance of lipoprotein remnants, proteases, or cytokines/growth factors in complex with alpha 2-macroglobulin as well as of plasminogen activators complexed with inhibitors. We investigated the expression of LRP/alpha 2-MR in healthy and atherosclerotic human arteries by in situ hybridization using an LRP/alpha 2-MR mRNA-specific riboprobe and immunocytochemistry using specific monoclonal antibodies. The cell types expressing LRP/alpha 2-MR were identified by immunolabeling of antigens specific for endothelial cells, smooth muscle cells, and macrophages. In normal arteries, LRP/alpha 2-MR mRNA and protein were found in smooth muscle cells of the media and vasa vasorum and in adventitial fibroblasts. Endothelial cells were negative for LRP/alpha 2-MR protein but positive for its mRNA. Atherosclerotic arteries exhibited a strong labeling for LRP/alpha 2-MR mRNA and protein that was observed in intimal smooth muscle cells exhibiting normal or foam cell characteristics and in lipid-laden cells positive for macrophage markers. A particularly high expression was detected in macrophages located in the cap of the lipid-rich necrotic core. These results suggest that cellular components of the atherosclerotic plaque express LRP/alpha 2-MR. This receptor may play an important local scavenger role for lipoprotein remnants, for growth factors/cytokines, and for extracellular protease-inhibitor complexes.

Arteries↗
PubMed1994

[Intramedullary pressure in intramedullary nailing of the femur and tibia].

Intramedullary nailing of shaft fractures of the femur and tibia is a recognized operative procedure and its use has even been enlarged by the introduction of the so-called interlocking technique. In recent years case reports have been published describing peroperative pulmonary embolism during reamed femoral nailing, suggesting either an unfavorable effect of the reaming or the pressure increase in the medullary cavity while reaming and nailing. In an in vitro study on explanted human femora and tibiae we investigated the intramedullary pressure increase in reamed and unreamed nailing procedures of both bones. A lower pressure increase was noted in unreamed nailing compared to reamed nailing in the femur (289/496 mm Hg) and in the tibia (128/>833 mm Hg). The unreamed tibial nailing displayed significantly less pressure increase than the unreamed femoral nailing (p = 0.01). Opening of the medullary cavity with the so-called cheese cutter (cannulated cutter over a centering pin) showed significantly greater pressure increase in the femur than in the tibia (p = 0.01). Pressure increase seems to be dependent of the mode of insertion of the unreamed nail (ram-blows versus manual insertion), although the difference in the tibial unreamed nailing is statistically not significant.

Biomechanical Phenomena↗
PubMed1994

[Ruptured cystadenoma of the pancreas].

There are many potential reasons for an acute abdomen. Very rare is a rupture of a cystadenoma of the pancreas. We describe such a case of an 85-year old woman, who was treated with an internal drainage of the cyst with a Roux-Y-loop, as at the time of the emergency operation the histological diagnosis was not known. As for the age of the patient and her general condition a secondary procedure with total resection of the mucinous cyst was not carried out. The post-operative course was uneventful up to three months, when the patient died in a geriatric home due to a antibiotic-resistant urosepsis. Literature is reviewed and our case is discussed in respect to recent publications.

Abdomen, Acute↗
PubMed1993

[Malleolar fractures with ankle joint instability--experience with the positioning screw].

UNLABELLED: Malleolar fractures with an unstable ankle joint require additional stabilization. Different implants exist: We present the results of 135/155 patients treated with the so-called positioning screw. In 123 patients the positioning screw showed a spontaneous loosening with functional treatment and was therefore removed with the rest of the implants after eight to twelve months. In twelve cases the screw was broken. In 3/21 patients with the old 3.5 mm cortical screw with a core diameter of 1.9 mm in a correct position and in 9/113 patients with the new 3.5 mm cortical screw with inner core of 2.4 mm in an incorrect position. CONCLUSION: Positioning screws require early removal only if they fail to loosen or if a persistent limitation of dorsiflexion is still present after three months.

Adult↗
PubMed1993

Intramedullary pressure in reamed and unreamed nailing of the femur and tibia--an in vitro study in intact, human bones.

The generation of intramedullary pressure during nailing of the femur and the tibia using reamed and unreamed nailing techniques was investigated and compared in an in vitro study in intact, cadaveric human bones. The pressure was assessed by distal supracondylar measurements via a small hole in the metaphyseal cortex. No significant difference in the intramedullary pressure increase was seen in the femur whether a reamed or unreamed nailing technique was used in contrast to the tibia (p = 0.01). A distal venting hole in the femur did not lower the increase in pressure during insertion of an unreamed nail. Using the cannulated cutter to open the medullary canal showed a significant increase in pressure compared to the use of the awl in the femur (p = 0.01), but not in the tibia.

Bone Nails↗
PubMed1993

[Epidemiology of winter sport injuries].

The region Davos/Klosters is a big wintersport area in Switzerland, where more than 5 million kilometers of vertical drop are skied per year. Over the last 20 years 28,777 patients with wintersport accidents have been treated in the 100-bed hospital of Davos, 85% of these patients have sustained their accident while skiing. An analysis of these datas show an increase of ski accidents as well as an increase of the distance skied. Especially an increase in snowboard accidents is noted over the last few years with a preponderance of lesions of the upper extremity. Injuries of the head, the trunk and simple skin lacerations remain stable over that period. Injuries of the upper extremity are increasing, whereas lower extremity lesions are slightly decreasing. There is a significant decrease of fractures of the leg, while at the same time an important increase of knee injuries is noted. Young patients below 20 years and those between 31 and 40 years of age sustained less accidents over the last 20 years, while the rest of the alpine skiers remain more or less stable in their accident incidence.

Adolescent↗
PubMed1993

[Calcaneus extension with the pinless external fixator].

Calcaneus traction is a common temporary procedure in fractures of the lower leg, when an internal fixation is not permitted for soft tissue reasons. Usually a Steinmann-pin or a K-wire is driven across the calcaneus, which is a simple manoeuvre performed in local anaesthesia. Infection due to this perforation of the calcaneus are rare, but signify for the patient a catastrophic complication. With the introduction of the pinless external fixateur in 1991 in clinical trials a very handy pinless-clamp exists, which can safely be anchored in the heel and thus permits safe calcaneus traction without any transosseous fixation. We have used this pinless clamp in 39 patients for various reasons and haven't stated any major complications. The clamp has proved to be very useful for temporary traction as well as for the fixation of the leg during closed intramedullary nailing using the fracture table.

Adolescent↗
PubMed1993

[Surgical technique in ski thumb injury].

The skier's-thumb, an instability of the ulnar collateral ligament (UCL) of the first metacarpo-phalangeal joint is one of the most common hand injuries in alpine skiing. In over 60% of our cases the ligament is ruptured, mostly near or at its distal insertion at the base of the first metaphalanx. Also a bony avulsion of the UCL at its distal insertion is not uncommon. A significant instability or a bony avulsion of the UCL with dislocation of the fragments is an indication for open reconstruction and stabilization. Good experience has been gained with a fish hook pull-out-wire technique. We describe the approach and the reconstruction technique.

Athletic Injuries↗
PubMed1993

Surgical treatment of humeral shaft fractures--the Basel experience.

One hundred twenty seven patients with fractures of the humeral shaft were treated by open reduction and internal fixation using 4.5-mm dynamic compression plates (DCP). Seventy one osteosyntheses were performed primarily, 36 following attempted closed reduction, and 20 secondarily after a failed conservative treatment of about 8 weeks. A primary radial nerve palsy was present in 19 patients, and appeared subsequently in four additional patients. One hundred two of the 127 patients could be clinically and radiologically examined 1 year after internal fixation: 89 patients (87.3%) had excellent or good results with full functional recovery. Thirteen patients (12.7%) showed a limited range of motion of either the shoulder or elbow or both. This was mostly because of other fractures of the same limb or persistent neurologic impairment. We observed two transitory postoperative nerve palsies, five early failures of internal fixation because of technical errors, two pseudarthroses and four postoperative infections, which healed with one exception by suction drainage and early removal of the plate. We conclude that a correct plate fixation of humeral shaft fractures in a selected group of patients represents an alternative to conservative treatment with the advantage of greater patient comfort.

Adolescent↗