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Biomedical subjects

A Krause

Publications and source records attributed to A Krause.

At least 145 records · Page 8Linked to original sources
PubMed1996

[2.7 mm (AO) or 2.0 mm miniplate osteosynthesis in mandibular fractures].

In a retrospective study on 302 patients, miniplate osteosynthesis (n = 236) and rigid internal fixation (n = 66) in patients with fractures of the mandible were investigated. The total complication rate following miniplate osteosynthesis was 6.5% compared to 12.7% following rigid internal fixation. Additional intermaxillary immobilisation did not avoid postoperative complications. In patients with multiple or comminuted fractures of the mandible, rigid internal fixation demonstrated a lower complication rate compared to miniplate osteosynthesis.

Adult↗
PubMed1996

Founder effect and prevalence of myotonic dystrophy in South Africans: molecular studies.

A high prevalence of myotonic dystrophy (DM) has been described in South African Caucasoid Afrikaans-speaking families in the northern Transvaal. Evidence is presented for a strong founder effect, with a single haplotype occurring on 68% of all Caucasoid DM chromosomes; among the Afrikaans speakers, the proportion was 83%. In addition to this major haplotype, five minor DM haplotypes in the Caucasoids and two minor haplotypes in DM individuals of mixed ancestry were found. All DM chromosomes, however, had a common haplotype core, namely, Alu (ins), HinfI-2 (intron 9), and TaqI-2 (D19S463). We have detected significant linkage disequilibrium between the DM mutation and particular alleles of the extragenic markers D19S112 and D19S207. Significant differences were found in allele and haplotype distributions in the Caucasoid DM and non-DM chromosomes and Negroid non-DM chromosomes. These findings together with the strong association of allele 3 at the D19S63 locus on 93% (14/15) of the South African DM chromosomes suggest that the majority of present-day DM mutations in South African Caucasoids may have originated from a common initial founder who introduced one of the European ancestral mutations.

Alleles↗
PubMed1995

Organization of the alpha-globin promoter and possible role of nuclear factor I in an alpha-globin-inducible and a noninducible cell line.

Nuclear factor I (NFI) was suggested to be involved in the expression of the human alpha-globin gene. Two established cell lines, which express alpha-globin differentially, were therefore compared for differences in binding of NFI at the alpha-globin promoter in vivo. HeLa cells, in which alpha-globin is repressed, show a high density promoter occupation with several proteins associated with structurally distorted DNA. Cell line K562, which is inducible for alpha-globin, surprisingly was found to be heterogeneous consisting mainly of cells (approximately 95%) unable to express alpha-globin. However, the promoter of the nonexpressing K562 cells was clearly different from that of HeLa cells, being occupied only at basal transcriptional elements. Therefore, the alpha-globin gene in these K562 cells may not be truly repressed, but in an intermediate state between repression and active transcription. The NFI site of the alpha-globin promoter appeared occupied in HeLa but free of proteins in K562 cells. All cells of both cell lines produce NFI, but the composition and DNA binding affinity of NFI species differ significantly between the two cell lines. Therefore, distinct forms of NFI may repress alpha-globin transcription in HeLa cells. However, NFI is apparently not involved in establishing the latent transcriptional state of the majority of K562 cells.

Base Sequence↗
PubMed1995

Influence of cytokines on the density of beta 2-adrenergic receptors on peripheral blood mononuclear cells in vitro.

Previous investigations have demonstrated a decrease of the number of beta 2-adrenergic receptors (beta 2R) on peripheral blood mononuclear cells (PBMC) in patients with rheumatic diseases that correlated with the systemic inflammatory activity. However, the main factor(s) modulating the beta 2R on lymphocytes in inflammatory diseases are still unidentified. The present study aimed at evaluating the influence of interleukin 1 beta (IL-1 beta) and interleukin 2 (IL-2) on the number and on the dissociation constant (KD) of beta 2R on PBMC in vitro. PBMC from healthy volunteers were incubated with different concentrations of IL-1 beta (10-100 U/ml) or IL-2 (10-50 U/ml) for 1,6,12,24 and 72 hours (h), respectively. Cultures with medium alone served as controls. beta 2R were determined using a radioligand binding assay with 125Iodo-cyanopindolol. The results showed a significant spontaneous decline of beta 2R after 72 h (mean +/- SEM = 2674 +/- 392 binding sites/cell (bs/c) vs. 1131 +/- 149 bs/c P < 0.02). IL-2 at a concentration of 50 U/ml diminished this spontaneous reduction of beta 2R numbers significantly (control: 1439 +/- 139 bs/c vs. IL-2: 1724 +/- 107 bs/c, P < 0.05). However, beta 2R densities did not hold baseline levels and were still significantly lower as compared to preculture values. Incubation with 100 U/ml IL-1 beta for 6 h induced a significant increase of beta 2R densities (control: 1760 +/- 214 bs/c vs. IL-1: 2233 +/- 424 bs/c, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Simulation of mechanical respiration using a multicompartment model for ventilation mechanics and gas exchange.

The mechanical respiration of intubated patients is a process which is influenced by many parameters and, through its many interactions, is extremely complex. Taken by itself the logical analysis of this complexity is extraordinarily difficult and leads very often to false conclusions. For that reason computer simulation of complex systems by means of the computer is an important tool in the analysis of these processes. Required is a model which describes the actual behavior of the system. However, it should not be overlooked that a model always describes only a portion of reality. Models having exclusively to do with ventilation mechanics or with gas exchange cannot simulate the interactions between the two. To accomplish this purpose, an improved model is necessary, including both partial processes and thereby capturing the complexity of the system. Accordingly, both ventilation mechanics and gas exchange have been integrated equally into the newly developed model for the simulation program Simu Vent. The core of the program builds a functional multicompartment model of the lungs and considers the partial processes ventilation mechanics, gas transport, gas mixing and gas exchange. Further considered are the respirator, blood circulation and peripheral compartments. The program runs under a graphical user interface, allowing its easy use. Responsible for this ease is the user's ability to interact with the program while simulation is in progress and the specially designed graphic screen mask. Comparing measured with simulated values demonstrated that the measured curve can be simulated with minimal error. Furthermore, the multicompartment model describes disruptions in distribution. Simu Vent's application is especially well advised in the description and analysis of the theoretical fundamentals of mechanical respiration. This aspect is meaningful above all in education and research, rendering these two the model's main areas of use.

Computer Simulation↗
PubMed1995

[Responsibility for patient education and incidence of homologous blood transfusions in unilateral breast cancer operations].

According to a judgement by the German Federal Court of 17 December 1991 the surgeon is legally bound to inform the patient before hand of the risk of a possible homologous blood transfusion during surgery. If the transfusion probability exceeds 5%, this obligation is really relevant, 228 patients with primary breast cancer of stage pT1 - 3N0 - 2M0 had been treated either radically (n = 146) or by a breast-preserving operation (n = 82) from January 1989 to December 1993. 400 to 800 ml erythrocyte preparations had been placed at disposal in advance for each patient. The rate of blood transfusions, pre- and postoperative haemoglobin (Hb), age, tumour size, lymph node involvement, kind and duration of operation as well as postoperative course have been analysed 43 of 228 (18.9%) patients received a homologous blood transfusion within 24 hours after operation. Transfusion rate per year decreased from 39.4% (1989) to 44.8% (1990), 12.2% (1991), 16.6% (1992) and 3.1% in 1993. On the contrary mean pre-and postoperative haemoglobin levels did not differ significantly (p < 0.05) between the different years: 13.4 +/- 0.8 respectively 12.1 +/- 1.1 g/dl (1989) and 13.5 +/- 1.3 respectively 12.1 +/- 1.3 g/dl (1993). Patients who had transfusions were significantly (p < 0.05) more likely to suffer from preoperative anaemia and larger tumors, and they have been treated by mastectomy more frequently compared to patients without transfusion. There were no correlations between transfusions and age, tumour size, lymph node involvement, kind and duration of operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Putschkowaskaja corneal protection].

BACKGROUND: Excessive cornea defects after chemical, thermal and microbiological damages respectively trophic disturbances often demand measures for conservation of the bulbus. PATIENTS AND METHODS: In the time between 1969 and 1993 22 patients were provided with a "Keratoplasty according to Putschkowskaja": circular cut at the recipient eye 0.15 mm deep, trepan diameter 8.5 to 13 mm, without lamellar preparation, covering with a donor cornea of normal thickness by silk single sutures. RESULTS: In 19 eyes the primary aim, the conservation of the bulbus, could be achieved. The complete transplant was mostly rejected after several months, only in two patients it healed by vascularisation. In one patient an abscess arose between recipient--cornea and transplant, which made explantation necessary. The histological examination of the transplant showed a purulent inflammation, swelling of the parenchym, partly absence of keratocytes and endothel cells, and a defect in the Bowman membrane. CONCLUSION: The "Keratoplasty according to Putschkowskaja" can be useful as "living contact lens" besides other surgical measures for treatment (primary conservation of the bulbus) of excessive cornea defects. It seems that the existence of Bowman and Descemet membrane in the transplant prevents the decomposition of the donor cornea for a rather long time. By then the cornea defect has often healed leaving scars.

Adolescent↗
PubMed1995

Immunology of reactive arthritides.

Reactive arthritis (ReA) and Lyme arthritis together comprise a pair of chronic inflammatory diseases of the joints. Although differing in detail, these relatively rare diseases are related in their immunopathology to the much commoner rheumatoid arthritis (RA), for which they serve as both model and control. The trigger for rheumatoid arthritis is unknown, but for these rarer diseases triggering occurs by certain well-defined bacterial infections. Arthritis is an uncommon outcome of these infections, for reasons unknown, and the development of chronic, as distinct from brief, arthritis is even rarer; again, the reasons are unknown. Not only does knowing the trigger greatly assist us in understanding these diseases, so also does knowing the contrasting pattern of Th1 versus Th2 cytokines observed in RA and ReA. ReA and Lyme arthritis are here considered in the wider setting of infections where chronic morbidity arises first from hypersensitivity, and perhaps finally from autoimmunity, such as occurs in some of the major tropical diseases. The immunology of ReA and Lyme disease is surveyed in detail, concentrating on T cells and including an update on the Lyme vaccine(s). Additional sections deal with the enigma of HLA B27, with epidemiological findings relevant to the chronicity of ReA and to the need for enlarged prospective studies of ReA in the setting of a developing country.

Arthritis, Reactive↗
PubMed1995

[Immunohistologic tumor cell detection in lymph nodes in node negative breast cancer: correlation with "established" and "recent" prognostic factors].

OBJECTIVES: The prognostic value of immunohistochemically detected micrometastases in lymph nodes as well as its association with newer prognostic factors is discussed controversially. PATIENTS AND METHODS: Using a monoclonal pancytoceratine antibody 1807 axillary lymph nodes of 122 pT1-2N0M0-patients were examined. Histological findings, established and newer prognostic factors were investigated additionally. The mean follow up time was 50 months. RESULTS: The detection of micrometastases in 16 of 122 (13.1%) patients were related with a prognostic disadvantage for recurrence free survival (p = .03). Tumour size, grading, vessel invasion and S-phase, but not the detection of micrometastases, were confirmed as independent prognostic factors in nodal negative patients by Cox-regression. CONCLUSION: Immunohistochemically detected micrometastases in axillary lymph nodes are of prognostic and therapeutic value but they are not independent prognostic factors.

Biomarkers, Tumor↗
PubMed1995

[The use of lymphocyte cultures for the investigation of drug biotransformation].

In the present paper the rat lymphocytes and mouse myeloma cell culture are developed as in vitro test systems and used for the investigation on the biotransformation of drugs. The rat lymphocyte culture was established as a suspension culture after the isolation of the cells from the spleen of male wistar rats by mechanical disaggregation and density gradient centrifugation with a yield of 10(7) cells per spleen and a viability of 80%. The addition of the mitogens PHA and Con A to the culture stimulated the proliferation of the lymphocytes leading to a doubling of the number of cells comparing with control cultures. Myeloma cells are a permanent cell line of B-lymphocytes. The cultivation was carried out as stationary suspension. The marked proliferation of the cells could be increased by addition of Con A. The biochemical properties of both kinds of cells are qualitatively comparable. Cytochrome P-450 mediated demethylase activities could be detected, which were 5-10 fold higher in myeloma cells. The pretreatment with the enzyme inductors phenobarbitone and 3-methylcholanthrene as well as the addition of the mitogens PHA and Con A increased these turnover rates. Reductive and conjugating activities were not present in the cultures. The established and characterized in vitro systems were applied for the investigation on the biotransformation of 4 potential drugs. The cardiac effective Trapidil (Rocornal) derivative AR 12463 (5-piperidino-7-[N-pentyl-N-(beta-hydroxyethyl)]- amino-s-triazolo[1,5-a]pyrimidine) is transformed in lymphocyte and myeloma cell cultures in two compounds. These substances revealed as the hydroxypentyl- and the hydroxypyrimidine derivative.(ABSTRACT TRUNCATED AT 250 WORDS)

Aminopyrine↗
PubMed1995

[Experiences with 2 different techniques of breast reduction-plasty].

About 58 patients with reduction mammoplasty is reported. 27 women were operated after the technique of Beller and Wagner, 31 women after the technique of Bostwick. The average weight of reduced breast tissue was about 800 g per side in both techniques. The results are reported and critically discussed. The authors prefer the method of Bostwick because of the possibility of more individuality and variability in breast surgery.

Adult↗
PubMed1995

[Transfusion incidence and indications for homologous blood sparing measures in single stage breast carcinoma operations].

Under a ruling by the Bundesgerichtshof from December 17, 1991 (AZ VI ZR 40/91), the surgeon is obliged to inform a patient about the risks of a possible blood transfusion if the transfusion frequency is 5% or more. Between January 1989 and December 1994, 273 patients with primary breast cancer at the stages pT1-3, N1-2, M0 underwent one-time modified radical mastectomy (n = 164) or a breast conserving operation (n = 109) in our hospital. The number of blood transfusions, pre- and postoperative haemoglobin, age, tumour size, lymph node involvement, kind and duration of the operation and the postoperative course were analysed. In all, 44 of the 273 patients (16.1%) received an homologous blood transfusion perioperatively. The annual transfusion rates were 39.4% (1989), 44.8% (1990), 12.2% (1991), 16.6% (1992) and 3.1% (1993), falling to 2.2% in 1994. The mean pre- and postoperative haemoglobin concentrations did not differ significantly (p > 0.05) over the years: 13.4 +/- 1.0 g/dl and 12.0 +/- 1.1 g/dl in 1989 and 13.7 +/- 1.2 g/dl and 11.8 +/- 1.2 g/dl in 1994. Patients who received transfusions had preoperative anaemia (p < 0.021), bigger tumours (p < 0.0005) and mastectomy operations significantly more frequently than patients not given transfusions. There were no correlations between transfusions and age, lymph node involvement and kind and duration of operation. We conclude that, cognizant of a transfusion frequency of 2.2% in our hospital in one-time breast cancer operations, only patients with anaemia or large tumours require blood transfusions, for which autologous blood donations or normovolaemic haemodilution are the choices. The patients' attention is to be drawn to these. In cases of normal preoperative haemoglobin and small tumours, the physician should inform the patient that experience has shown that in all probability a blood transfusion will not be necessary and so a preoperative autologous blood donation or normovolaemic haemodilution can be dispensed with.

Adult↗
PubMed1994

Borrelia burgdorferi-induced ultrastructural alterations in human phagocytes: a clue to pathogenicity?

A chronic infection with the spirochaete Borrelia burgdorferi typically results in a multistage, multisystem illness. Thus, Lyme borreliosis may provide an interesting model to study the pathomechanisms of microbial persistence. In the present investigation, human peripheral blood monocytes, polymorphonuclear leukocytes, and synovial macrophages were incubated with B. burgdorferi and examined by light and electron microscopy. It was found that incubation with the spirochaetes induced distinct features in the phagocytes. Features which may be related to the pathogenesis of Lyme disease included the segmental uptake of spirochaetes with leaky lysosomes, the invagination of large membrane areas, the extra-lysosomal degradation of internalized B. burgdorferi cells and, finally, the formation of mononuclear syncytial cells and homotypic cell clusters. Features of unknown relevance were the occurrence of two types of cytoplasmic inclusion bodies and exocytic vesicles. These novel findings suggest that reactive alterations of the phagocytes may contribute to the pathogenesis of Lyme borreliosis, which could help to focus future histopathological studies. Moreover, these results may provide new insights into the pathogenesis of other infectious diseases characterized similarly by microbial persistence.

Borrelia burgdorferi Group↗
PubMed1994

The high frequency of the Hb B2 variant in the Herero population: a founder effect?

The beta-globin gene cluster haplotype associated with the delta-globin variant Hb B2 was determined in Herero individuals from six different families, in order to establish whether founder effect was responsible for the high frequency of this variant in the population. The electrophoretic detection of Hb B2 was confirmed at the molecular level by polymerase chain reaction, followed by Cfo I digestion. The haplotype associated with the Hb B2 chromosome was determined in two families, and was shown to be the same. In the remaining four families the haplotypes could not be established conclusively, but were consistent with the haplotype observed in the other two families. The high gene frequency of Hb B2 is thus likely to have resulted form founder effect.

Black People↗
PubMed1994

[Puerperal and non-puerperal mastitis].

Report about 82 women with inflammatory breast diseases, who were hospitalized during january 1988 and december 1993. 37 women had a puerperal mastitis, 39 women a non-puerperal mastitis and 6 had perimamillary abscesses. In 35 (42.7%) of the 82 patients abscesses occurred. The different etiology and bacteriology as well as resulting treatment guidelines are discussed. In the treatment of puerperal mastitis, staphylococcus effective penicillins keep the first place. The therapy of non-puerperal mastitis consists in prolactin inhibiting drugs and broad spectrum antibiotics. In abscesses and fistulas surgical treatment is necessary, the same in recurrences. If the process is suspicious for breast cancer diagnostic excision is to perform.

Abscess↗
PubMed1994

[Postmenopausal hemorrhage and endometrial cancer in tamoxifen therapy].

Report about 8 patients with endometrial pathology during tamoxifen therapy: 1 endometrial cancer, 1 adenomyosis uteri and 6 endometrial polyps. The knowledge about effects of tamoxifen on endometrium and possibilities of prevention are discussed. Sonographic screening of patients during tamoxifen therapy and if need by endometrial biopsy is necessary especially if tamoxifen is given longer than 2 years. No more than 30 mg should given in adjuvant therapy.

Aged↗