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Biomedical subjects

A Kirsch

Publications and source records attributed to A Kirsch.

At least 37 records · Page 2Linked to original sources
PubMed1996

Horseshoe Le Fort I osteotomy in combination with endosteal implants--a median-term follow-up study.

Fourteen patients with Class VI resorption of the maxilla were treated with horseshoe Le Fort I osteotomy. In 11 cases, the procedure was followed by the placement of endosteal implants. In six patients, simultaneous placement of implants was carried out, while in five patients this was done in a second procedure. Ten patients wore their implant-supported dentures. In one patient, 5/8 implants were lost due to nonintegration. Three patients lost one implant each. The total number of implants placed was 76, and the survival rate of the implants was 88.1%. In the one-step procedure (n = 42), the survival rate was 84.8%; in the two-step procedure (n = 34), 92.3%. In comparison of the one-step to the two-step procedure, there was no statistically significant difference (P > 0.11) between the amount of marginal peri-implant bone loss and the condition of the peri-implant soft tissues as measured 2 years after implantation.

Adult↗
PubMed1996

Interference of blood leucocytes in the measurements of immature red cells (reticulocytes) by two different (semi-) automated flow-cytometry technologies.

Flow cytometrical methods have been introduced recently as an alternative to the enumeration of reticulocytes by microscopy. Two of these methods have gained widespread use in haematological practice; the multiparametric flow cytometer using thiazole orange staining (Retic-Count, FACScan) and the single-application reticulocyte counter using auramine-O staining (R-series, Sysmex). Several studies have emphasized the excellent correlations between microscopy and these techniques. The purpose of our study has been to examine the specificity of these automated devices with regard to cells classified as 'reticulocytes' and the effect that this may have on measures of reticulocyte maturity. Our results indicate that the specificity of reticulocyte measurements by both the Sysmex R-1000/-3000 and the Retic-Count system is relatively low. This is due to the presence of leucocytes amongst cells classified as reticulocytes. These leucocytes display intense staining with either dye, leading to an erroneous estimation of RMI (thiazole orange) and high fluorescence count (R-1000/-3000). This error is directly correlated with the leucocyte count. The basis for reticulocyte identification should be improved before automated estimation of reticulocyte maturation can be used in clinical practice.

Automation↗
PubMed1994

Characterization and measurement of CD34-expressing hematopoietic cells.

Because of availability of anti-CD34 monoclonal antibodies, multiparameter flow cytometry has become the tool of choice for determination of hematopoietic stem and progenitor cells. This report describes general techniques for quantitation and characterization of CD34-expressing cells by flow cytometry.

Adult↗
PubMed1993

Practical stress absorption by means of modified abutments. Case presentations.

To improve the success rates of implants, numerous clinicians suggest progressive bone loading. The effectiveness of progressive loading can be enhanced by the use of stress-absorbing components. This paper reviews a polyoxymethylene intramobile element, which provides a resilient connection between the implant and prosthesis and reduces the stress transmitted to the implant and supporting bone, resulting in an improved long-term performance. This paper also introduces a relatively new intramobile connector system, which provides stress absorption and distributes the masticatory load in physiologic manner to the bone surrounding the implants. Types of bone and their locations in the mandible and the maxilla are discussed. Four case reports are used to illustrate the clinical procedure. The learning objective of this article is to expand the knowledge of available enhancements in stress absorption.

Dental Abutments↗
PubMed1993

[Diffuse demineralization of the lumbar spine. Magnetic resonance tomography studies of osteoporosis and plasmacytoma].

On plain radiographs, diffuse infiltration of the spine in multiple myeloma may present as diffuse demineralization. Differentiation from osteoporotic changes is then difficult. 15 patients with multiple myeloma and 15 patients with osteoporosis were prospectively examined by MRI using plain and contrast enhanced gradient echo techniques. Examinations were evaluated for lesions and diagnosis was made by two independent observers. Contrast enhancement was visible in lesions detected in myeloma patients and in compression fractures. Fractures could be differentiated from malignant lesions by the fact that there was no multiplicity of enhancing lesions. Contrast enhanced opposed phase gradient echo sequences seem suited for the detection of vertebral involvement in myeloma.

Adult↗
PubMed1992

Mobilization of circulating haemopoietic cells (blood stem cells) by GM-CSF in patients with malignancies.

Autologous reinfusion of circulating haemopoietic progenitor and stem cells (blood stem cell transplantation) has emerged as an alternative to autologous bone marrow transplantation in a variety of malignant diseases. Major obstacles associated with harvest of blood stem cells by leukapheresis are: 1. relatively high costs, and 2. discomfort caused to the patient, as generally five to ten settings of leukapheresis are necessary to harvest a number of blood stem cells sufficient for haemopoietic restitution following myeloablative therapy. GM-CSF recently has been shown to effectively increase circulating haemopoietic cells, when given subsequent to even highly-toxic therapy. This report summarizes our data on mobilization of blood stem cells by GM-CSF cells in multiple myeloma patients.

Combined Modality Therapy↗
PubMed1992

Effect of food restriction on the phosphocreatine energy shuttle components in rat heart.

Malnutrition has been associated with changes in cardiac metabolism and performance. We have previously reported a diabetic-type cardiomyopathy associated with chronic food restriction and weight loss. Because the creatine-phosphocreatine-creatine kinase system is important in the contractile process, we studied the components of this system in rats fed a food-restricted diet (33% of control animal intake). After 4 weeks of food restriction, total creatine kinase (CK) activities were reduced by 28% in ventricles and by 38% in atria. The CK isoenzymes in the heart were not equally affected. The BB isoenzyme was decreased by 77% and 78%, the MB isoenzyme by 45% and 43%, the MM isoenzyme by 22% and 19% and CKmito by 16% and 15% in ventricles and atria, respectively. In contrast, brain CK activity which is predominantly the BB isoenzyme, was slightly higher in the food-restricted than in control rats. Further studies on ventricular tissue from food-restricted rats revealed a 27% decline in myofibrillar CR activity and a 58% decline in myofibrillar ATPase activity. Phosphocreatine and creatine concentrations were not changed by food restriction, however, ATP was decreased by 23% in ventricles from rats on the restricted diet. Cardiac mitochondrial oxidative phosphorylation was also impaired. State 3 respiration with alpha-ketoglutarate was reduced 20% in the food-restricted heart. These changes are compared to those which we previously observed in the diabetic rat heart and the significance of these findings is discussed.

Adenosine Triphosphatases↗
PubMed1992

[Magnetic resonance tomographic screening studies of the bone marrow with gradient-echo sequences. II. Gadolinium-DTPA-supported studies of plasmocytoma patients].

MR imaging was performed in 19 patients with proven multiple myeloma. Both plain and Gd-DTPA enhanced in-phase and opposed-phase gradient-echo techniques were used (0.1 mmol Magnevist/kg body weight). Plain, opposed-phase imaging demonstrated more lesions than plain in-phase imaging (35 vs. 16); enhanced opposed-phase imaging demonstrated more lesions than plain opposed-phase and enhanced in-phase imaging (47 vs. 35 and 17 lesions). These results suggest that enhanced opposed-phase images which have a high contrast between normal and infiltrated bone marrow are especially suited for MR screening in multiple myeloma.

Bone Marrow↗
PubMed1992

Replication of parvovirus B19 in hematopoietic progenitor cells generated in vitro from normal human peripheral blood.

Erythroid progenitor cells generated in vitro from peripheral human blood in the presence of interleukin-3 and erythropoietin were infected with human parvovirus B19. B19 virus DNA replication was highest 48 to 72 h after infection, and maximum levels of B19 virus proteins were detected in culture supernatants at 72 to 96 h after infection. B19 virus propagated in vitro was infectious. This cell culture system with peripheral blood cells facilitates studies in vitro of B19 virus replication.

Blood↗
PubMed1992

Diabetic type of cardiomyopathy in food-restricted rats.

We have demonstrated that food restriction that is associated with weight loss can produce a type of cardiac dysfunction similar to that produced by diabetes. As in diabetic atria, the food-restricted atria had a 2-fold increase in contraction force, rate of force development, and rate of force decline compared with controls. Both food-restricted and diabetic atria could tolerate anoxia better than controls. The contractile function of the whole perfused heart from the food-restricted rat was reduced, as in the case of the diabetic heart. As the left ventricular volume was increased, the left ventricular developed pressure and the rate of rise and fall in pressure were significantly reduced in both food-restricted and diabetic hearts, compared with those of age- and weight-matched controls. The positive inotropic responses of atria and whole perfused heart to increasing concentrations of extracellular calcium were similarly altered in food-restricted and diabetic hearts. The possible molecular mechanisms of these findings and some of the differences observed between food-restricted and diabetic hearts are discussed.

Adenosine Triphosphate↗
PubMed1992

The journey to quality improvement in home care.

In a creative approach to establishing an agency quality improvement program, the journey to excellence in home care services was enhanced by a collaborative effort between a home care vice president and a quality assurance expert. The result was a methodology that has been incorporated into a five-year commitment to a plan for quality improvement through out the agency.

Consultants↗
PubMed1991

Alteration of the phosphocreatine energy shuttle components in diabetic rat heart.

Considering the important role of the phosphocreatine energy shuttle in contractile function of the heart we decided to study the different components of this shuttle in STZ-induced diabetic rat heart with a known diabetic related cardiomyopathy. Diabetes produced a gradual decline in total CK activity, reaching a maximum of 35-40% decrease after 4 weeks of diabetes, in both atria and ventricles. All of the CK isoenzymes including the mitochondrial CK (CKm) were reduced but to a different extent in these two tissues. The percentage reduction in diabetic ventricles was BB greater than MB greater than CKm greater than MM and in atria was CKm greater than BB greater than MB greater than MM. A major difference between atrium and ventricle was the greater loss of CKm in diabetic atria than diabetic ventricle (75% in atria vs 32% in ventricle). The B subunit seemed to be the one that was affected the most followed by CKm isoenzyme and then the M subunit. The bound myofibrillar CK isoenzyme, expressed as units of activity/mg of myofibrillar protein, was not affected by 4 weeks of diabetes. The high energy phosphates were also reduced in diabetic heart with a greater reduction in phosphocreatine (43-45%) and a smaller change in ATP (27%). Mitochondrial oxidative phosphorylation with alpha-ketoglutarate was reduced (55%) in diabetic heart, whereas, there was no difference when succinate was used as substrate. These changes were reversible by 4 weeks of insulin treatment. The loss of CKm, phosphocreatine and the reduction in mitochondrial oxidative phosphorylation, could result in an inefficient phosphocreatine energy shuttle which could contribute to the cardiac functional defects associated with diabetes.

Animals↗
PubMed1991

[A new implant system in head and neck surgery].

Defects in the head and neck region following extensive tumor removal are sometimes difficult to reconstruct by local or free flaps. An epithesis is a recommended alternative in defects of the ear, the nose or the orbital region. Nevertheless problems may arise in the appropriate fixation of the epithesis. With the intermobile-cylinder-implant-system (IMZ), the epithesis is firmly fixed by means of osseointegration of the implants and an abutment in the area of the defect. The various steps of the operation and clinical applications are presented.

Ear Deformities, Acquired↗
PubMed1991

Productive infection of in vitro generated haemopoietic progenitor cells from normal human adult peripheral blood with parvovirus B19: studies by morphology, immunocytochemistry, flow-cytometry and DNA-hybridization.

Parvovirus B19 exerts a highly selective cytopathic effect on erythroid progenitor cells. Studies so far on the pathogenesis of B19-infection have been performed using bone marrow samples providing large amounts of erythroid progenitor cells. Extensive study, however, has been hampered by the limited access to bone marrow samples. We have designed a liquid culture method allowing the generation of large numbers of erythroid progenitor cells, initiating cultures with CD3- and CD14-poor peripheral blood mononuclear cells. Following a 12 d preincubation in liquid cultures containing recombinant human interleukin 3 (rhIl-3) and recombinant human erythropoietin (rhEpo), cells harvested from the liquid cultures were exposed to B19-containing plasma, followed by a further cultivation in liquid culture for up to 96 h. Cells expressing the CD13 and the glycophorin A (GlyA) antigens, respectively, were monitored sequentially by flow-cytometry, demonstrating a selective inhibition of GlyA-positive cells following B19-inoculation. Typical morphological changes were observed on cytocentrifuge-spots, and typical giant-cells were identified as staining for GlyA. Productive infection by B19 was demonstrable, as B19-DNA increased by about x 100 after 72 h of culture. The liquid culture method generating erythroid target cells for effective infection by B19 virus promises to be a useful and easily accessible tool for further research on B19 infection of haemopoietic cells.

Cells, Cultured↗
PubMed1991

Phenotyping of peripheral blood hemopoietic progenitor cells--in vitro cultures using CD34-/CD33-immunomagnetic purging.

In contrast to many detailed studies on the antigenic profile of hemopoietic progenitor cells from human bone marrow, sparse information, so far, has been gathered with regard to the antigen expression of hemopoietic progenitors present in peripheral blood. Previous studies by multiparameter flow-cytometry have revealed substantial differences of the coexpression of the CD33-, CD19-, and CD74- antigens, respectively, on CD34-positive cells from blood versus those from bone marrow, respectively. Immunomagnetic purging with monoclonal antibodies detecting the CD34-, and the CD33- antigen, respectively, has been used to further characterize the expression of these antigens on day 8 and d-14 granulocyte/macrophage and erythroid colonies as grown from circulating progenitor cells. Purging with CD34 monoclonal antibody abrogated all colony formation, whereas purging with CD33 antibody led to differential inhibition of the various progenitors. Purging bone marrow cells with CD34 antibody, an inhibition of only about 25% was observed with regard to erythroid colonies, whereas an inhibition of about 85% was observed for CFU-GM. These findings reinforce the view that circulating progenitor cells represent relatively immature stages of differentiation, when compared to bone marrow progenitors. Particularly, d-8 erythroid colonies from blood do not represent the equivalent of the genuine CFU-E as described from bone marrow, but they seem to be early stages of BFU-E development.

Adult↗
PubMed1991

[Investigations on secondary emission of metallic implant materials Ti and Ta following radiation].

Two implant materials, titanium and tantalum, were investigated for their electron emission in response to therapeutic tumor irradiation and were compared, in this context, to a substance equivalent to bone. The reaction of titanium was found to be similar to that of bone, whereas substantive increase in radiation was caused by tantalum which, consequently, should be removed from the radiation field.

Bone and Bones↗